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Auswahl der wissenschaftlichen Literatur zum Thema „Apical area“
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Zeitschriftenartikel zum Thema "Apical area"
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Esposito, John V. „Apical Violation in Periapical "Area" Cases“. Dental Clinics of North America 34, Nr. 1 (Januar 1990): 171–78. http://dx.doi.org/10.1016/s0011-8532(22)01175-2.
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MORALES, EDUARDO A., MARIA HELENA NOVAIS, CARLOS E. WETZEL, LUC ECTOR und MARIA MANUELA MORAIS. „Fragilaria odeloucaensis sp. nov. (Bacillariophyta, Fragilariaceae) a diatom from temporary streams in southern Portugal“. Phytotaxa 555, Nr. 3 (26.07.2022): 217–30. http://dx.doi.org/10.11646/phytotaxa.555.3.1.
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A new species of araphid diatom is described from a temporary stream in southern Portugal, Fragilaria odeloucaensis sp. nov., which belongs to the group of Fragilaria with widely linear to lanceolate valve outline, spaced striae, lacking spines, and with well-developed apical pore fields. The new taxon can be distinguished based on five unique features within this group, the lanceolate valves with capitate apices, the zig-zagged axial area, the central area with squared fascia, the apical pore fields clearly sunken into the valve apices and the heterovalvar frustules (with respect to striae distancing). Ecological features of the type locality and an additional sampling point where the new species was found are given, together with a discussion of the taxonomic position of the new species within Fragilaria, and the approach used herein for the identification of diagnostic features. This approach includes a detailed analysis of the internal and external characteristics of the axial area-virgae-striae complex, central area, apical pore fields and differences among valves of the same frustule, in addition to the traditional valve shape and morphometric features.
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Xie, Shicong, Frank M. Mason und Adam C. Martin. „Loss of Gα12/13 exacerbates apical area dependence of actomyosin contractility“. Molecular Biology of the Cell 27, Nr. 22 (07.11.2016): 3526–36. http://dx.doi.org/10.1091/mbc.e16-05-0305.
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During development, coordinated cell shape changes alter tissue shape. In the Drosophila ventral furrow and other epithelia, apical constriction of hundreds of epithelial cells folds the tissue. Genes in the Gα12/13 pathway coordinate collective apical constriction, but the mechanism of coordination is poorly understood. Coupling live-cell imaging with a computational approach to identify contractile events, we discovered that differences in constriction behavior are biased by initial cell shape. Disrupting Gα12/13 exacerbates this relationship. Larger apical area is associated with delayed initiation of contractile pulses, lower apical E-cadherin and F-actin levels, and aberrantly mobile Rho-kinase structures. Our results suggest that loss of Gα12/13 disrupts apical actin cortex organization and pulse initiation in a size-dependent manner. We propose that Gα12/13 robustly organizes the apical cortex despite variation in apical area to ensure the timely initiation of contractile pulses in a tissue with heterogeneity in starting cell shape.
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Nugroho, Juni Jekti, und Aisyah Pertiwi Utami. „Apical patency as a way of preserving the apical third area of endodontic treatment“. Makassar Dental Journal 9, Nr. 3 (28.11.2020): 181–83. http://dx.doi.org/10.35856/mdj.v9i3.350.
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Introduction: The apical third of the root canal system is very complex portion and challenging during endodontic treatment. Blockage of the root canal in the apical region by remnants of hard tissue and soft tissue debris, may cause procedural errors such as apical transportations, ledge and perforation. These debris contain bacteria inducing periradicular disease. The apical patency technique is considered as a way for maintaining the apical part free of debris by recapitulation using a small K-file through the apical foramen to assure that the canal system is predictably negotiable. Aim: To review the significance of apical patency as one of clinical approaches to reduce treatment failure on endodontic therapy. Conclusion: Apical patency may im-prove the result of cleaning procedure, for both mechanically and biologically way, in apical third area of canal system.
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Campos, Marcio Jose da Silva, Helen Vidon Gomes, Paula Liparini Caetano, Marcelo Reis Fraga und Robert Willer Farinazzo Vitral. „Is relevant the underestimation of irregular apical root resorption by periapical radiographs?“ HU Revista 45, Nr. 3 (28.11.2019): 237–43. http://dx.doi.org/10.34019/1982-8047.2019.v45.28678.
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Introduction: Periodic control of root resorption during orthodontic treatment is frequently made by two-dimensional radiographic examinations, in which irregular resorptions are not detected buccolingually. Aim: Quantifying the resorbed root area of incisors with irregular apical root resorption underestimated by two-dimensional radiographic methods. Materials and Methods: Cone beam computed tomography images of 18 patients whose incisors presented irregular apical root resorption underestimated by two-dimensional radiographic methods and their contralateral correspondents without resorption were evaluated. In sound incisors, a regular apical root resorption was simulated at the same height as that of the irregularly resorbed incisors. The apical and total root surface areas of the incisors with irregular root resorption and simulated regular root resorption were measured and compared. The Student´s t test for paired samples was used at a level of significance of 0.05. Results: The apical area of the incisors with irregular root resorption was significantly smaller than that of the incisors with simulated regular resorption (p<0.001). There was no significant difference in the comparison between total root surface areas (p=0.435). Conclusion: Underestimation of the irregular root resorption shown on two-dimensional images was significant when analyzing the apical area of the tooth. However, when considering the total root surface area of the tooth, which is responsible for the most part of the periodontal support, such underestimation was not significant.
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Carvalho, Rafael Henrique de Oliveira, Marcelo Santos Coelho, Hugo Victor Dantas, Frederico Barbosa de Sousa, Aline Cristine Gomes Matta, Adriana de Jesus Soares und Marcos Roberto dos Santos Frozoni. „Influence of different working lengths on the shaping ability of Reciproc Blue in the apical third and apical foramen“. Brazilian Journal of Oral Sciences 22 (19.12.2023): e231400. http://dx.doi.org/10.20396/bjos.v22i00.8671400.
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Aim: This study aimed to assess the shaping ability of Reciproc Blue in the apical third and apical foramen of moderately curved canals at different working lengths (WLs), by micro-computed tomography. Methods: Thirty-six mesial roots (mesiobuccal and mesiolingual canals) were included, each with 2 separate root canals and independent apical foramina, according to type IV of Vertucci’s classification of first and second mandibular molars. The canals were instrumented at three different WLs: G-1, 1mm short of the major apical foramen; G0, at the major apical foramen; G+1, 1mm beyond the major apical foramen. The groups were assessed for changes in root canal volume and untouched wall area in the apical third. Groups G0 and G+1 were also compared for percentage of untouched walls at the apical foramen. One-way ANOVA (post hoc Tukey test) and Student’s t-test adopted a 5% level of significance. Results: Root canal volumes (mm3) in the apical third were 22.86±10.46, 44.48±24.91, and 55.71±21.32 in G-1, G0 and G+1, respectively. G-1 volume following instrumentation increased significantly less than that of G0 or G+1 (P>.05); G0 did not differ from G+1. The percentage of untouched wall area in the apical third did not differ among the three groups (P>.05). G0 and G+1 did not differ regarding untouched walls in the major apical foramem walls. Conclusion: Extending the WL from 1mm short of the apical foramen to a point at and beyond the WL increases the apical third volume without increasing the prepared area. Untouched surface areas of the apical foramen were not modified by instrumentation at or beyond the foramen.
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Kaur, H., S. Chaudhary und P. Tangde. „MTA : Boon to Apexification“. Journal of Oral Health and Community Dentistry 7, Nr. 2 (2013): 114–18. http://dx.doi.org/10.5005/johcd-7-2-114.
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ABSTRACT A significant problem associated with the endodontic treatment of necrotic teeth with open apices is achieving an acceptable seal in the apical area to allow compaction of root filling material. The procedure to create an apical barrier with a hard tissue at the root end is termed as Apexification. Calcium hydroxide is currently the most accepted material for the same. Because of the certain inadequacies associated with Calcium hydroxide Apexification, employing of an apical plug using MTA (Mineral Trioxide aggregate) has gained popularity in recent years. This article is thus an insight to the evolution and recent trends in Apexification.
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Hillary, Natasya, Citra Kusumasari und Ahmed Abdou. „Bioceramic cement as a reparative material in apexification of immature permanent tooth: a case report“. Jurnal Kedokteran Gigi Universitas Padjadjaran 36, Nr. 4 (31.01.2024): 111. http://dx.doi.org/10.24198/jkg.v36i4.49880.
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ABSTRACTIntroduction: Bioceramic cement is the latest material of choice that can be used in apexification, resorption case, perforation repair, and known as high-quality sealing material in regenerative endodontics. The treatment of apexification in immature teeth poses a considerable challenge due to the wide root canal, the absence of apical constriction, and thin dentin walls, thus requiring specialized techniques and materials for managing teeth with an open apex. The objective of this case report is to delineate the treatment of apexification in teeth with open apices using the latest bioceramic material (Bio-C® Repair). Case report: An 11-year-old female patient with chief complaints of swollen gums covering the cervical third of the crown after her front tooth was broken due to a fall two years ago. Radiographic examination showed a wide root canal with an open apex and radiolucency in the apical area. The apexification procedure with an apical plug was performed with Bio-C® Repair, followed by anatomical fiber post and direct composite restoration for the final restoration. In the 2-month and 4-month control, the periapical lesion showed signs of healing on radiographs. Bioceramic materials act as an artificial barrier in open apex management and provide various advantages, such as shortening treatment time, strengthening dentin structure, and possessing bioactive properties that can induce healing. The orthograde placement of bioceramic material is challenging in terms of length control. Using bioactive materials can reduce the risk of adverse impacts from material extrusion. Conclusion: A new bioceramic material (Bio-C® Repair) is recommended for the apexification procedure because it can overcome the limitations of MTA (e.g., tooth discoloration, handling difficulties, prolonged setting time, and the release of heavy metals.Keyword open apices, immature permanent tooth, apexification, bioceramic, apical barrier techniqueSemen biokeramik sebagai material apeksifikasi gigi permanen imatur: laporan kasusABSTRAKPendahuluan: Material biokeramik merupakan material pilihan yang digunakan untuk menangani prosedur apeksifikasi, resorpsi, perforasi, dan sebagai material regeneratif endodontik. Perawatan apeksifikasi pada gigi yang belum matang menimbulkan tantangan besar karena saluran akar yang lebar, tidak adanya konstriksi apikal, dan dinding dentin yang tipis, sehingga memerlukan teknik dan material khusus untuk merawat gigi dengan apeks terbuka. Tujuan laporan kasus ini adalah untuk menjelaskan perawatan apeksifikasi pada gigi dengan apeks terbuka menggunakan material biokeramik terbaru (Bio-C® Repair). Laporan kasus: Pasien perempuan 11 tahun datang dengan keluhan pembengkakan pada gusi yang menutupi sepertiga servikal mahkota gigi, setelah gigi tersebut patah karena terjatuh dua tahun yang lalu. Pemeriksaan radiografis menunjukkan saluran akar yang lebar dengan apeks terbuka serta radiolusensi pada area apikal. Prosedur apeksifikasi dilakukan dengan pembuatan penutupan apikal (apical plug) menggunakan material biokeramik Bio-C® Repair, yang diikuti pemasangan pasak fiber anatomis dan tumpatan resin komposit sebagai restorasi akhirnya. Pada kontrol 4 bulan, lesi periapikal menunjukkan tanda kesembuhan secara radiograf. Material biokeramik berperan sebagai penutupan apikal artifisial pada manajemen apeks terbuka dan memberikan berbagai keuntungan seperti mempersingkat waktu perawatan, menguatkan struktur dentin, dan memiliki sifat bioaktif sehingga dapat menginduksi penyembuhan. Penempatan material biokeramik pada ujung apeks secara orthograde merupakan prosedur yang cukup sulit terutama saat mengontrol panjang kerja. Penggunaan material bioaktif dapat menurunkan risiko dampak negatif dari ekstrusi material. Simpulan: Material biokeramik baru seperti Bio-C® Repair menjadi rekomendasi untuk tatalaksana prosedur apeksifikasi karena dapat mengatasi berbagai keterbatasan MTA seperti diskolorasi gigi, kesulitan handling, waktu pengerasan yang lama, dan pelepasan kandungan metal berat yang toksik.Kata Kunciapeks terbuka, gigi permanen imatur, apeksifikasi, biokeramik, teknik penutupan apikal
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Souza, Ronaldo Araújo, Yara T. Corrêa Silva Sousa, José Antônio Poli de Figueiredo, João Da Costa Pinto Dantas, Suely Colombo und Jesus Djalma Pécora. „Relationship between files that bind at the apical foramen and foramen openings in maxillary central incisors - a SEM study“. Brazilian Dental Journal 22, Nr. 6 (2011): 455–59. http://dx.doi.org/10.1590/s0103-64402011000600003.
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Considering that instrumentation of the apical foramen has been suggested for root canal infection control, this study analyzed the relationship between the files that bind at the apical foramen and the foraminal openings in 50 maxillary central incisors. After preparation of the pulp chamber, access to the canal was obtained with #1 and 2 LA Axxess and K-files with tip cut were inserted up to the apical foramen until binding was felt. The files were fixed with methyl cyanoacrylate and the tooth-file sets were cross-sectioned 10 mm short of the apex. Scanning electron microscopic analysis was carried out and files and foraminal areas were measured using Image Tool software. Statistically significant difference (p<0.0001) was found between files and the apical foraminal areas. The mean foraminal area was 3.8 times larger than the mean file area. The results of this study suggest that it would require 4 files of greater size beyond the one that bound to the foramen in order to allow a better relationship between files and apical openings of maxillary central incisors.
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Adamyan, K. G., A. L. Chilingaryan, N. G. Mkrtchyan und L. G. Tunyan. „Mechanisms and predictors of ischemic mitral regurgitation at rest and on exertion in patients at early stage of myocardial infarction“. Russian Journal of Cardiology 25, Nr. 2 (11.03.2020): 52–59. http://dx.doi.org/10.15829/1560-4071-2020-2-3098.
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Aim. Determination of the mechanisms and predictors of ischemic mitral regurgitation (IMR) at rest and on exertion in patients at early stage of myocardial infarction (MI).Material and methods. Seventy-seven patients with inferoposterior MI and 79 patients with anteroseptal apical MI were examined on the 7th day at rest and after exertion. We determined the degree of IMR (according to the PISA method), posteromedial and anterolateral papillary muscle (PM) displacement, closure height of the mitral valve (MV), systolic and diastolic mitral valve orifice area, volume of the left ventricle (LV), LV contractility index, deformation of the infarction regions, general LV deformation, deformation and systolic dyssinchrony of the PM.Results. IMR was more common in inferior MI (42% vs 28%). LV volumes in cases with anteroseptal apical MI and IMR were greater and LV deformation was less than in patients without IMR. In inferoposterior MI and IMR, differences were observed in the index of local contractility and function of the posteromedial PM. The differences in MI of both localizations and IMR compared with MI without IMR were the areas of the mitral orifice and dyssinchrony of the PM. The degree of IMR after exertion did not depend on the degree of IMR at rest. Predictors of IMR at rest in MI of both localizations were the apical displacement of MV closure and the area of the mitral orifice. In inferoposterior, posteromedial PM displacement, deformation of the infarcted areas, PM dyssinchrony were also predictors. In anteroseptal apical MI, the area of the mitral orifice was the predictor of IMR. Predictors of anteroseptal apical MI after physical exertion after inferior MI were mitral orifice areas, contractility index, displacement and deformation of the posteromedial PM. In anteroseptal apical MI, the IMR predictors were MV closure height and systolic area of mitral orifice.Conclusion. The study confirms the significance of changing the spatial orientation of the MV structures in MI of both localizations, impaired regional contractility in inferoposterior MI and LV volume in anteroseptal apical MI at early stage of the disease.
Dissertationen zum Thema "Apical area"
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Cachoux, Victoire. „Biophysical Regulation of Epithelial Apoptosis“. Electronic Thesis or Diss., Université Paris sciences et lettres, 2022. http://www.theses.fr/2022UPSLS023.
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L’apoptose est une forme de mort cellulaire programmée qui joue un rôle clé lors de la morphogenèse (acquisition de formes et structures pendant le développement), dans l’homéostasie des tissus adultes, ainsi que dans certaines maladies telles que les cancers. Alors que les signaux moléculaires responsables du déclenchement de l’apoptose ont été l’objet de multiples recherches, le rôle de facteurs biophysiques dans le contrôle de la mort cellulaire reste peu connu. Durant ma thèse qui avait pour modèle d’étude le thorax dorsal (ou notum) de la pupe de drosophile, j’ai développé des techniques d’analyse quantitative de données vidéo-microscopiques qui, combinées à l’utilisation d’outils génétiques de pointe, visaient à comprendre la régulation biophysique de l’apoptose. Tout d’abord, j’ai cherché à caractériser les caractéristiques précoces des futures cellules apoptotiques et ai découvert deux caractéristiques géométriques prédictives de ces cellules : des petites aires apicales absolue et relative. Ensuite, j’ai étudié en détail ces deux facteurs géométriques et ai montré que leurs actions dans le contrôle de la mort faisaient intervenir deux voies de signalisation génétiques différentes, voies que j’ai identifiées. Ce faisant, j’ai également découvert une connexion inédite entre prolifération et mort cellulaire dans le contrôle du développement tissulaire. En conclusion, mon travail apporte un éclairage nouveau à notre compréhension de l’apoptose épithéliale en identifiant des facteurs géométriques impliqués de façon très précoce dans la régulation de la mort cellulaireApoptosis is a form of programmed cell death which plays a key role in shaping multicellular organisms during development, in adult tissue homeostasis, as well as in pathological conditions such as cancer. While the molecular pathways triggering apoptosis have been extensively studied, the role of biophysical factors in driving cell death is far less understood. In particular, cell size and geometry impact a variety of cell processes, yet their possible interplay with apoptotic pathways remains unknown. Using the developing dorsal thorax (or notum) of the Drosophila as a model, I developed during my PhD advanced quantitative analyses of time-lapse microscopy data that, combined with the powerful genetic tools available in Drosophila, aimed at uncovering the biophysical mechanisms regulating apoptosis. First, I investigated the early characteristics of apoptotic cells and discovered two predictive geometrical features of these cells: small absolute and relative apical areas. Second, I studied in detail these two geometrical parameters and showed that their actions were linked to distinct genetic pathways, which I identified. By doing so, I also uncovered a novel coupling between cell proliferation and cell death in the control of tissue development. Overall, this work provides a new perspective to the understanding of epithelial apoptosis by identifying geometrical parameters that play an early role in the regulation of cell survival
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Melo, Marcello Ghetti de. „Quantificação da área ocupada pela guta-percha e pelo Resilon em canais achatados após termoplastificação“. Universidade do Estado do Rio de Janeiro, 2008. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=3062.
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O presente trabalho teve por objetivo quantificar, comparativamente, a área de preenchimento de dois materiais obturadores sólidos, cones de guta-percha (GP) e cones de Resilon (R), no terço apical de incisivos inferiores humanos, ex vivo, obturados pela técnica da onda contínua de condensação. Os espécimes foram submetidos a um protocolo, desde a cirurgia de acesso até o final do preparo químico-mecânico e divididos aleatoriamente em dois grupos, de 21 dentes cada, de acordo com o material utilizado. Não foi utilizado cimento endodôntico em nenhuma das amostras. Após a obturação, as amostras foram seccionadas transversalmente em dois níveis, a 3 e a 5mm do ápice, e subdivididas em grupos de acordo com a altura de corte e do material obturador, sendo estabelecido: GP3 (guta-percha com corte a 3mm), GP5 (guta-percha com corte a 5mm), R3 (Resilon com corte a 3mm) e R5 (Resilon com corte a 5mm). Posteriormente, as amostras foram submetidas a um processo de lixamento e polimento e examinadas em microscópio óptico por reflexão com aumento de 50x a 100x. Para a análise e processamento digital das imagens, foi utilizado o sistema de imagens Axio Vision 4.6 para Windows, sendo obtidas as medidas para cada área observada em micrômetros (μm); uma da área da cavidade, e outra da área de material obturador. Foi aferido o grau de circularidade de cada amostra, por uma fórmula matemática utilizada automaticamente pelo programa, onde 1 (um) é considerado o círculo perfeito e, quanto mais achatado o canal, mais tendente a 0 (zero) nesta escala. Obteve-se a área do canal, a circularidade de 0 a 1, a área preenchida pelo material obturador e, a porcentagem da área de preenchimento do material obturador em relação à área do canal. Foi realizado o cruzamento dos grupos dois a dois pelo teste t de Student, sendo verificada diferença estatisticamente significante entre os grupos GP3 e R3, tendo o grupo R3 apresentado maior porcentagem de área do canal radicular preenchida pelo material obturador em suas amostras (p<0,05). Na relação da circularidade com a quantidade de preenchimento, com o teste de Correlação de Pearson, não foi observada forte correlação entre a forma final do canal (relação de circularidade) e a quantidade de preenchimento do canal radicular pelos materiais obturadores testados. Conclui-se que houve grande variação de preenchimento mínimo e máximo em todos os grupos testados e o Resilon apresentou maior porcentagem de preenchimento de área do canal radicular em suas amostras.The aim of this study was to determine a quantitative comparison of gutta-percha and Resilon filled areas in the apical third of human mandibular incisors, ex vivo, after obturation by continuous wave condensation technique. The tooth samples were submitted to irrigation and instrumentation protocol and randomly divided in two groups of twenty-one each. No sealer was used. After obturation, a horizontal section was cut 3mm and 5mm from the apical foramen of each tooth. The two groups were subdivided according to cut height and obturation material as follows: GP3 (gutta-percha with 3mm section), GP5 (gutta-percha with 5mm section), R3 (Resilon with 3mm section) e R5 (Resilon with 5mm section). The samples were later prepared for microscopic analysis and photomicrographs of each apical surface were taken at magnifications from 50x to 100x. The cross-sections of the canal areas with the obturation materials were measured using an image analysis program, obtaining the measurement of each canal area and filled area in micrometers. The circular form of each sample was rated automatically by a mathematic formula used by the program, where 1 (one) is considered a perfect circle, and as it flattens, the value approaches 0 (zero). The digital imaging analysis obtained the canal area, the circular form from 0 to 1, the area filled by obturation material, and the percentage of material filled area relative to the canal area. The percentage difference of the filled canal area among the groups was analyzed using a Students t-test. Significant differences were found between GP3 and R3. The greatest percentage of filled canal area occurred in the R3 group (p<0,05). With respect to the relationship of the circular form with the quantity of filling material, by using the Pearson Correlation test, no significant correlation was found between the final form of the canal and the quantity of root canal filling by the obturation materials tested. In conclusion, a great variation in the minimum and maximum filled percentage occurred all groups tested and the Resilon group showed a higher percentage of filled root canal area in their samples.
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Garbuzov, Mihail. „Helping the honey bee and other flower-visiting insects in urban areas“. Thesis, University of Sussex, 2014. http://sro.sussex.ac.uk/id/eprint/51671/.
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As is much of the world's biodiversity, bees and other flower-visiting insects are in global decline, largely due to human activities. The impacts of humans on wildlife can be ameliorated, at least to an extent, by wildlife-friendly management practices in both rural and urban areas. This thesis comprises two introductory chapters (Part 1), followed by a series of ten research chapters (Parts 2 - 5) aimed at informing management practices that encourage bees and other flower-visiting insects in urban areas, and ends with a concluding chapter (Part 6). The projects are grouped in four parts making contributions to four broad areas of research. Part 2 is concerned with evaluating the attractiveness of ornamental garden plants to insect flower-visitors. Individual projects examine the advice currently available to gardeners via recommended plant lists, and describe surveys of plant varieties grown in a public garden (Southover Grange garden, Lewes), a Plant Heritage national collection of asters (Picton Garden, Malvern), and the experimental gardens planted on campus of the University of Sussex, Brighton, as well as in towns of Plumpton and Magham Down. Part 3 evaluates the attractiveness to insects of urban wild flowers, including those growing in amenity grass areas in parks, and the effects on their abundance and diversity of the various mowing regimes, as well as the attractiveness of the common autumn flowering ivy. Part 4 uses waggle dance decoding to investigate honey bee foraging in the urban landscape of Brighton, with an additional particular focus on foraging on spring-blooming oilseed rape in the surrounding agricultural land. Part 5 examines an aspect of good practice in urban apiary set up, the use of lattice fence or hedge barriers, which should facilitate beekeeping in urban areas, including in private gardens and allotments.
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Forero-Ortega, Anny Julieth. „Tectonic compartimentation of an area in the Ribeira belt, between Itapeva and Ribeirão Branco (SP): Itaiacoca Group and Bairro dos Prestes Formation“. Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/44/44141/tde-18072018-081845/.
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A partir de mapeamento geológico, análises petrográficas, geoquímicas, geocronológicas e microestruturais em rochas metavulcânicas e metassedimentares, foi possível reconhecer duas sucessões de rochas metassedimentares - metavulcânicas de fácies xisto verde no sudoeste do Terreno Apiaí no cinturão Ribeira (entre Itapeva e Ribeirão Branco, SP): o Grupo Itaiacoca e a Formação Bairro dos Prestes. O Grupo Itaiacoca, datado pelo método U-Pb em zircão, apresentou idades neoproterozoicas entre 602,7 ± 24 (metabasito) e 613,4 ± 9,6 Ma (metatufo). É constituído por uma sucessão de metargilitos, filitos e quartzitos de granulação fina (Formação Água Nova), intercalados com metacalcários calcíticos e dolomíticos com estruturas estromatolíticas e pequenas camadas de tufo metavulcânico (Formação Bairro dos Campos) em contato transicional com rochas metabásicas, metadolomitos, e talco xisto e clorita xisto (Suíte Metabásica da Fazenda Velha) com quartzitos maciços (Formação Serra dos Macacos) sobrepondo todas as unidades. Com base na caracterização geoquímica, as metabásicas com assinaturas toleíticas e calci-alcalinas possuem padrões de manto tipo MORB com contribuição de componentes de subdução típicos de basaltos de bacias de retroarco. A Formação Bairro dos Prestes foi depositada entre 1761 ± 14 e ~ 1800 Ma (datada pelo metodo U-Pb SHRIMP em zircão de metariodacito e metavulcanossedimentar, respectivamente). A formação é composta por filitos, localmente com estruturas amigdaloides, em contato transicional com quartzitos de granulação fina a média, com camadas subordinadas de metaconglomerados e rohas metavulcânicas félsicas com assinatura calci-alcalina de alto K. Na área de estudo também estão presentes as rochas sedimentares paleozoicas do Grupo Itararé, os metarenitos quartzo-feldspáticos ediacaranos de granulação grossa da margem direita do rio Apiaí-Guaçu, a suite granítica ediacarana Três Córregos e o Complexo paleoproterozoico Apiaí Mirim. O Complexo Apiaí Miriam compreende paragnaisses e quartzitos micáceos de granulação média a grossa afetados por metamorfismo de fácies anfibolito, enquanto a Suite Granítica Três Córregos é constituída por monzogranitos porfiríticos e sienogranitos subordinados. A idade máxima de deposição obtida pelo método U-Pb LA-ICP-MS em zircões detríticos do Metarenito Apiaí-Guaçu foi de 588,4 ± 1,8 Ma, o que permite correlacioná-la com as bacias da fase de transição do ciclo Brasiliano. O arranjo estrutural compreende acamamento sedimentar (So) e três foliações tectônicas (Sn, Sn+1 e Sn+2). A foliação principal (Sn) é caracterizada por xistosidade ou clivagem ardosiana, geralmente paralelas a So, apresentando direções NE-SW e mergulhos elevados. Os planos Sn são deformados pelas clivagens de crenulação Sn+1 e Sn+2. A foliação Sn+1 está associada a dobras apertadas com planos axiais com direção NW desenvolvidas nos quartzitos, nas sequências metavulcanossedimentares e rochas pelíticas, enquanto a folição Sn+2 associa-se como dobras abertas com planos axiais com direção NE nos quartzitos e filitos. A área de estudo também é afetada por falhas NNW-SSE e NNE-SSW. A análise microestrutural realizada em amostras da Formação Bairro dos Prestes e do Complexo Apiaí Mirim através de técnicas de Orientação Preferencial de Forma (OPF) e Orientação Cristalográfica Preferencial (OCP), indica uma forma oblata para o elipsoide de deformação finita com planos XY na direção NE-SW e X-direções com alta obliquidade, correlacionadas com os dados estruturais medidos em campo. As temperaturas de deformação calculadas a partir do ângulo de abertura das estruturas dos eixos-c variam de 531 ° C - 593 ° C a 613 ° C -703 ° C. Foram influenciadas pela presençia de água e pelos processos de dissolução, sendo por vezes maior que as temperaturas indicadas pelas associações minerais metamórficas (fácies xisto verde). As temperaturas de deformação também exibem um gradiente regional, com as temperaturas mais altas a sul e mais baixas a norte. Um regime transpressivo com predominância de cisalhamento puro é sugerido com base na forma oblata e nas altas obliquidades dos eixos X do elipsoide de deformação finita. O contexto geológico, os dados geocronológicos e geoquímicos sugerem que o Grupo Itaiacoca e a Formação Bairro dos Prestes podem ser correlacionados às formações Pirapora do Bom Jesus e Boturuna do Grupo São Roque. O Grupo Itaiacoca é interpretado como depositado em uma bacia de retroarco associada ao oceano Adamastor, provavelmente representando uma sutura ediacarana entre o Terreno Apiaí e o Craton Paranapanema.Field geological mapping, petrographic, geochemical, geochronological and microestrutural analysis obtained from metavolcanic and metasedimentary rocks led to the recognition of two greenschist facies metasedimentary-metavolcanic rock successions in Southwest of Apiaí Terrane in Ribeira belt (between Itapeva and Ribeirão Branco, SP): the Itaiacoca Group and Bairro dos Prestes Formation. The Itaiacoca Group dated by U-Pb method in zircon yield Neoproterozoic ages of 602.7 ± 24 (metabasite) and 613.5 ± 9.6 Ma (metatuff), it is constitute by a succession of metamudstone, phyllites and fine-grained quartzites (Água Nova Formation), intercalated with calcitic and dolomitic metalimestone with stromatolite structures and small beds of metatuff (Bairro dos Campos Formation) in transition contact with metabasites, metadolomites, talc schists and chlorite schists (Fazenda Velha Metabasic Suite), and massive quartzites (Serra dos Macacos Formation) overlapping all the units. Based on geochemistry characterization, the metabasites with tholeiitic and calc-alkaline signatures have patterns of MORB-type mantle with contribution of subduction components typically of back-arc basin basalts. The Bairro dos Prestes Formation was deposited between 1761 ± 14 and ~1800 Ma (Zircon SHRIMP U-Pb data of metarhyodacite and metavolcanosedimentary rock, respectively), it is composed of phyllites sometimes with amygdaloid structures in transitional contact with fine to medium grained-quartzites and restricted metaconglomerate and felsic metavolcanic rocks with high-K calc-alkaline signature. In the study area is also present the flat-lying sedimentary rocks of the Paleozoic Itararé Group, the Ediacaran fine to coarse-grained feldspathic quartz metasandstones of the Apiaí-Guaçu metasandstone, the Três Córregos Granitic Suite and the Paleoproterozoic Apiaí Mirim Complex. The Apiaí Miriam Complex comprises paragneiss and medium to coarse grained micaceous quartzite affected by amphibolite facies metamorphism, while the Três Córregos Granitic Suite consists of porphyritic monzogranite and subordinate sienogranite. The maximum depositional age calculated by U-Pb ICPMS- LA of detrital zircons of the Apiaí-Guaçu metasandstone was 588.4±1.8 Ma which allows to correlate it with the transition stage basins of the Brasiliano Cycle. The structural arrangement comprises relict bedding (So), and three tectonic foliations (Sn, Sn+1 and Sn+2). The main foliation (Sn) is characterized as a schistosity or slaty cleavage, generally parallel to So, presenting NE-SW strikes and steep dips, and it is deformed by Sn+1 and Sn+2 crenulation cleavages. The Sn+1 is associated with tight folds with NW axial-planes in quartzite metavolcanosedimentary and pelitic sequence, and the Sn+2 with open folds with NE axial-planes in quartzite and phyllite rocks. The study area is also affected by NNW-SSE and NNE-SSW faults. The microstructural analysis was performed in samples of Bairro dos Prestes Formation and Apiaí Mirim Complex through Shape Preferential Orientation (SPO) and Lattice Preferred Orientation (LPO) techniques, determinate an oblate shape for the finite strain ellipsoid with XY planes with NE-SW strike and X-directions with high rake, correlated with the structural data measured in field. The deformation temperatures calculated from opening-angle of c-axis structures vary from 531°C-593°C to 613°C-703°C, they were influenced by water weakling and solution-transfer process, being sometimes higher that the temperatures indicated by the metamorphic mineral assemblages (facies greenschists). The deformation temperatures also display a spatial gradient, in the south the highest temperatures are present, while in the north, the lowest temperatures were calculated. A transpressive regime with predominance of pure shear is suggested based on the oblate shape and high rake X axis of the finite strain ellipsoid. The geological context, geochronological and geochemical data suggest that the Itaiacoca Group and Bairro dos Prestes Formation can be correlated with Pirapora do Bom Jesus and Boturuna formations of São Roque Group. The Itaiacoca Group is interpreted as arc-back-arc basin system is associated with the large Adamastor Ocean, and probably represents an Ediacaran suture zone between the Apiaí Terrane and the Paranapanema Craton.
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Schaffer, M. J. „Spatial aspects of bumble bee (Bombus spp. Apidae) foraging in farm landscapes“. Lincoln University, 1997. http://hdl.handle.net/10182/2243.
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Bumble bees (Bombus spp.: Apidae) are valuable pollinators of many crop and wildflower species. However, in some situations their potential is limited. Evaluation of, and management to improve bumble bee efficacy should include spatial information which is currently limited. Distance and direction determine the success of gene flow via pollen cross-over within and between plant populations at several scales. Studies of movement by bumble bees at large scales in semi-natural and intensively managed habitats are scarce. Few studies of bumble bee dispersal from the nest exist, particularly in relation to crops. At a small scale, directional rather than random movement between flowers has benefits for pollen flow. Results to date of directionality studies at small scales and their interpretation are inconsistent. The purpose of this thesis was to assess distances and directions moved by foraging bumble bees at a range of scales in two contrasting farm habitats in order to predict their pollination potential. A novel method was developed to mark automatically all the occupants of nests of bumble bees B. terrestris (L.) placed around a Lucerne seed crop Medicago sativa L. in New Zealand. Reobservation data from eight nests showed that of bumble bees which foraged within the crop, 81 % travelled ≤ 50 m and 56% ≤ 20 m from their nest. Results should be interpreted with extreme caution because fewer than 1 % of bumble bees marked at nests were reobserved in the crop. Because it was not established where the other 99% of the bumble bees went, foraging areas for nests could not be calculated as anticipated. Theories to explain the non-specificity of bumble bees to the crop include; resource depletion near nests, competition with honey bees in the crop, or an evolved strategy to disperse in order to minimise nest predation. Lucerne flowers contained a significantly lower concentration of sugar in nectar, and significantly fewer pollen grains than did those of purple loosestrife Lythrum salicaria L., a species on which bumble bees appeared to forage in preference Lucerne. The higher rewards offered by L. salicaria may have diverted bumble bees from the less-rewarding Lucerne crop. In a Norwegian meadow system, all foraging bouts by bumble bees B. lucorum (L.) within a patch of wood cranesbill flowers Geranium sylvaticum L. were random with respect to direction. This result is not consistent with predictions, based on optimal foraging theory, that movement should be directional to enable optimal pollen flow, and to avoid revisitation of just-emptied flowers by the pollinator. A medium-scale study of several bumble bee species moving between patches of northern wolfsbane Aconitum septentrionale Koelle in Norway revealed considerable loyalty by bumble bees to patches in which they were marked. In a different landscape-scale study (over 5 ha), several bumble bees exhibited a high degree of loyalty to areas in which they were marked (87% were reobserved ≤ 50 m from marking points). These restricted movement patterns are discussed in terms of potential pollen flow. Of 260 bumble bees marked, only five were recorded crossing between meadows, which could be a result of innate loyalty to small forage areas, an artefact of the sampling technique used, or forest boundaries acting as physical impediments to movement. In the future, spatial data of the type collected in this thesis will aid in the management of bumble bee populations to achieve both commercial and conservation goals. Spatial data can be applied to predict the optimal placement of artificially-reared nests, predict suitable isolation distances for pure seed crops, and aid in the positioning of supplementary forage sources and nest-site refuges.
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Aleixo, Kátia Paula. „Sazonalidade na disponibilidade de alimento e dinâmica de forrageamento em Scaptotrigona aff. depilis (Hymenoptera, Apidae, Meliponini)“. Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/59/59131/tde-08072013-103620/.
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Estudos sobre a influência da variação sazonal na disponibilidade de recursos florais na coleta de pólen e néctar pelas abelhas sem ferrão são escassos na literatura devido à ausência de métodos viáveis de se quantificar o alimento armazenado nas colônias por longos períodos. O objetivo desse estudo foi avaliar o armazenamento de alimento em colônias de Scaptotrigona aff. depilis em relação a distribuição espaçotemporal dos recursos florais em uma área urbanizada na região tropical, bem como estratégias utilizadas pelas colônias no período de menor disponibilidade alimentar. De abril de 2011 a março de 2012, a estrutura da comunidade vegetal do campus da Universidade de São Paulo, cidade de Ribeirão Preto, foi avaliada sob os aspectos da composição florística e fenologia de floração para avaliar a ocorrência de sazonalidade na distribuição dos recursos florais disponibilizados para as abelhas. Concomitantemente, foi analisado qualitativamente e quantitativamente o armazenamento mensal de pólen e néctar em colônias experimentais (CEs) de S. aff. depilis, formadas a partir da remoção de colônias mães (CMs) de seus lugares originais e substituídas por caixas de madeira vazias, as CEs, em cujas as forrageiras armazenaram o alimento durante sete dias. No mesmo período de um ano, foi avaliada a produção mensal de cria nas CMs de S. aff. depilis por meio de fotografias tomadas na região da cria em intervalos de 24h durante quatro dias consecutivos. Espécies melitófilas floresceram durante o ano todo e, consequentemente, a disponibilidade de alimento para as abelhas foi contínua. A distribuição dos recursos foi sazonal, com abundância de disponibilidade na transição da estação seca com a chuvosa e na estação chuvosa. O armazenamento de alimento foi afetado pela associação entre a sazonalidade na disponibilidade de pólen e a temperatura ambiente. O pólen foi armazenado ao longo de todo o ano, ao passo que o néctar começou a ser armazenado no final da estação seca e permaneceu durante toda a estação chuvosa. Nas CEs, a maior quantidade de alimento foi armazenada na estação chuvosa, com pico no bimestre de fevereiro-março. Mesmo apresentando um hábito generalista, as forrageiras de S. aff. depilis intensificaram, espacial e temporalmente, a coleta de recursos em poucas fontes florais. As espécies Eucalyptus moluccana, E. grandis e Myracrodruon urundeuva foram preferencialmente utilizadas no armazenamento de pólen durante a estação seca, ao passo que durante a estação chuvosa apenas Schinus terebinthifolius foi a fonte preferencialmente utilizada. A sazonalidade na disponibilidade de pólen influenciou inclusive a produção de cria, a qual diminuiu na estação seca. A disponibilidade de pólen parece ser um fator central influenciando no crescimento e no desenvolvimento das colônias de S. aff. depilis.Studies on the influence of seasonal variation in the availability of floral resources on the collection of pollen and nectar by stingless bees are scarce due to lack of methods to quantify the stored food in the colonies for long periods of time. The aim of this study was to evaluate the storage of food in colonies of Scaptotrigona aff. depilis in relation to the spatiotemporal distribution of floral resources in an urbanized area in the tropical region, as well as assess the strategies used by the colonies during periods of food scarcity. From April 2011 to March 2012, the plant community structure in the campus of Universidade de São Paulo, located in the city of Ribeirão Preto, was studied under the aspect of floristic composition and flowering phenology to evaluate the occurrence of seasonality in the distribution of floral resources available to bees. Concurrently, it was analyzed the monthly storage of pollen and nectar in experimental colonies (ECs) of S. aff. depilis formed from removal of colonies (MCs) from their original places and replaced by empty wooden boxes, the ECs, whose foragers stored food for seven days. In the same period of an year, it was evaluated the monthly brood production in MCs of S. aff. depilis through photographs taken in the brood region at intervals of 24h for four consecutive days. Melittophilous were in bloom year-round, and therefore the availability of food resources was continuous for bees. The resource distribution was seasonal, with plenty of available resources in the transition from the dry to the rainy season and in the rainy season. The storage of food was affected by the association between the seasonal availability of pollen and ambient temperature. Pollen was stored throughout the year, while the nectar started to be stored in the dry season and remained throughout the rainy season. In ECs, the largest amount of food was stored during the rainy season, peaking in February-March. Even though foragers display a generalist habit, food collection was intensified at few sources in spatiotemporal scale. The species Eucalyptus moluccana, E. grandis and Myracrodruon urundeuva were preferentially used in the storage of pollen during the dry season, while Schinus terebinthifolius was the most frequently used species during the rainy season. Seasonality in pollen availability also influenced brood production, which decreased in the dry season. The availability of pollen seems to be a central parameter influencing the growth and development of S. aff. depilis colonies.
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Carantón, Omar Arvey Martínez. „Dinâmica Reprodutiva e Influência das Áreas de Congregação de Zangões na Africanização de Apis mellifera (Apidae: Apini) no Brasil“. Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/17/17135/tde-13062013-113316/.
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A introdução de 33 rainhas africanas (Apis mellifera scutellata) em 1956, com o objetivo de iniciar um programa de seleção e melhoramento genético no Brasil, e a posterior enxameação de algumas destas rainhas, deu inicio ao processo de Africanização, originando o poli-híbrido, denominado, Abelha africanizada. Este processo envolveu uma série de fatores biológicos e ambientais, cujas interações não são suficientemente claras. Os acasalamentos em abelhas melíferas ocorrem em sítios denominados como Áreas de Congregação de Zangões (ACZ), estes locais têm sido bem estudados em abelhas européias, porém, pouco pesquisados em abelhas africanizadas. Assim, é mister a necessidade de desenvolver novos estudos sobre o comportamento reprodutivo destas subespécies, que contribuíram para a rápida expansão das abelhas africanizadas nas Américas. Foram observados os comportamentos de vôos de 10 rainhas (Apis mellifera carnica e Apis mellifera africanizada) e de 126 e 146 zangões de cada raça, respectivamente. Observou-se 6 pontos, localizados no campus da USP de Ribeirão Preto, os quais poderiam ter uma maior concentração de zangões em vôo. Estes pontos foram analisados por meio de uma rainha fecundada presa a um balão preenchido com gás Helio e determinadas características ambientais. Todas as rainhas retornnaram ao núcleo com a marca de acasalamento e iniciaram o processo de postura. Os dados revelaram que não existem diferenças significativas (? = 0,05%) ao compararmos: A idade da rainha no seu primeiro vôo (T=123: P=0,185); a idade da rainha no vôo do acasalamento (t=1,721; P=0,104); o numero de vôos que cada rainha realizou (T=79,5; P=0,789); a duração do vôo de acasalamento (t=1,065; P=0,303); a temperatura no dia do vôo de acasalamento (t=0,263; P=0,796) e o horário do dia no qual ocorrem os vôos de acasalamento (t = 0,0; P=1,0). A atividade de vôo dos zangões carnicos nunca precedeu o horário as 14:15 e 14:30h para zangões carnicos e africanizados, respectivamente, confirmando que não existem diferenças significativas no período do dia em que estes realizam seus vôos (t = -3,11E-015; P = 1,000). Dos 6 pontos observados, somente um ponto não atraiu zangões à isca. Não foram encontrados diferenças significativas entre as diferentes ACZ (P = 0,109). Ao analisar a velocidade do vento (m/s), a analise de variância encontrou diferenças significativas entre as diferentes ACZ (P=<0,001), porém não influenciando a presença de zangões na isca. Dados coletados neste experimento revelaram que os zangões freqüentam estas áreas durante condições de vento superiores a 4 m/s, e em algumas ocasiões com ventos de 8.1 m/s. Também foi observado que os zangões realizam seus vôos de acasalamento em dias nublados e com pouca luminosidade. Não existiu uma preferência, pelos zangões, por determinadas ACZ, constatando-se que o ambiente oferece muitos espaços abertos típicos de ACZ, garantindo e facilitando o acasalamento destas abelhas.The introduction of 33 African queens ( Apis mellifera scutellata ) in 1956 , aiming to start a program of selection and breeding in Brazil , and later some of these swarming queens , began the process of Africanization , yielding poly - hybrid called , \" Africanized Bee \" . This process involved a number of biological and environmental factors whose interactions are unclear. Mating in honeybees occur at sites referred to as Areas of Congregation Hornets ( ACZ ) , these sites have been well studied in European bees , but little researched in Africanized bees . Thus , it is essential the need to develop new studies on the reproductive behavior of these subspecies, which contributed to the rapid expansion of Africanized bees in the Americas . Behaviors Flight 10 queens ( Apis mellifera and Apis mellifera Africanized carnica ) and 126 and 146 Hornets each race respectively were observed . There was 6 points , located in the USP , Ribeirão Preto , which could have a higher concentration of drones in flight campus . These points were analyzed by means of a fertilized queen attached to a balloon filled with helium and certain environmental characteristics. All queens retornnaram the core branded mating and begun the process of laying. The data revealed no significant differences when comparing : The age of the queen on her first flight (T = 123 : P = 0.185 ) ( = 0.05 % ? ) ; the age of the queen in flight mating ( t = 1.721 , P = 0.104 ) ; the number of flights that each queen performed (T = 79.5 , P = 0.789 ) ; the flight duration of mating ( t = 1.065 , P = 0.303 ) ; the temperature on the mating flight ( t = 0.263 , P = 0.796 ) and time of day in which mating flights occur ( t = 0.0, P = 1.0 ) . Flight activity of CARNICOS Hornets never preceded the hours 14:15 and 14:30 for CARNICOS and Africanized drones, respectively , confirming that there are no significant differences in time of day in which they perform their flights ( t = -3.11 and -015 , P = 1.000) . 6 of the observed points , only one point not attracted to the bait Hornets . No significant differences were found between the different ACZ (P = 0.109 ) . By analyzing the wind speed ( m / s ) , analysis of variance found significant differences between the different ACZ ( P = < 0.001), but not influencing the presence of drones at the bait . Data collected in this experiment revealed that the Hornets frequent these areas during windy conditions exceeding 4 m / s , and on some occasions with winds of 8.1 m / s . It was also observed that the Hornets perform their mating flights on cloudy days and low light . There was a preference by the Hornets , by certain ACZ , noting that if the environment offers many open spaces typical of ACZ , ensuring and facilitating mating these bees.
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Juhel, Jean-Baptiste. „Base de référence, impacts anthropiques et mesure s de protection pour les requins récifaux de Nouvelle - Calédonie“. Thesis, Nouvelle Calédonie, 2016. http://www.theses.fr/2016NCAL0002/document.
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L'impact anthropique sur les écosystèmes coralliens est aujourd'hui largement documenté, que ce soit sur la biodiversité qu'ils hébergent, leur diversité fonctionnelle, les services écosystémiques qu'ils procurent ou leur capacité de résilience. Parmi les groupes trophiques, les prédateurs apicaux en général et les requins en particulier, sont particulièrement sensibles aux perturbations d’origine humaine du fait de leurs traits d'histoire de vie conservateurs (e.g. croissance lente, maturité sexuelle tardive, faible fécondité). D'après certaines estimations, les populations de requins ont décliné de plus de 90% à l'échelle globale. Afin d'assurer le maintien de leurs populations et de leur rôle fonctionnel dans la communauté, il est nécessaire de mettre en place des mesures de gestion adaptées. Les objectifs de cette thèse sont de 1) faire le bilan des populations de requins de Nouvelle-Calédonie ; 2) déterminer l'efficacité des vidéos stéréoscopiques appâtées (S-BRUVS) pour recenser les requins en les comparant aux comptages en plongées (UVC) et évaluer leur possible amélioration ; 3) évaluer l'impact de la proximité humaine sur la diversité, l'abondance et le comportement des requins récifaux et 4) déterminer l'efficacité des mesures de gestion en place pour protéger ces espèces emblématiques. Les résultats des deux méthodes de recensement montrent un important déclin d'environ 90% des abondances de requins récifaux le long d'un gradient anthropique complet en Nouvelle-Calédonie alors que la pêche des requins est historiquement absente dans cet archipel. Une importante altération comportementale du requin gris de récif (Carcharhinus amblyrhynchos) face à la nouveauté d'un appât a été mise en évidence. Les individus se tiennent plus éloigné du dispositif, interagissent moins avec l'appât et mettent plus de temps pour le mordre avec l'augmentation de la proximité humaine. Cette dernière est le principal moteur de ce déclin d’abondance (46 à 71%) et de l'altération comportementale vers des individus plus craintifs (50 à 80%). Globalement, les aires marines protégées de Nouvelle-Calédonie ne sont pas efficaces pour la protection des requins. Néanmoins, la réserve intégrale Merlet héberge des populations de requins proche du niveau de récifs isolés de l’archipel et protège une partie du comportement. Les résultats de ce travail révèlent 1) l'importance et le caractère unique des récifs coralliens isolés ; 2) qu'en absence de pêche la proximité humaine conditionne l'abondance et le comportement des requins de récifs avec des conséquences écologiques potentielles sur l'ensemble du réseau trophique ; 3) que l'efficacité des AMPs réside dans leur capacité à exclure la présence humaine sur une surface suffisamment grandeAnthropogenic impacts on coral reefs are largely documented through changes in functional diversity, ecosystem services or resilience. Among trophic groups, apex predators in general and sharks in particular are the most sensitive to disturbance due to conservative life history traits (e.g. slow growth, late sexual maturity, low fecundity). By some estimates, shark populations have declined by >90% worldwide. To ensure the sustainability of their populations and their functional role in the reef community, appropriate management measures must be implemented. The aims of this thesis are 1) to assess reef shark populations in New Caledonia; 2) to evaluate the efficiency of stereo baited remote underwater video systems (S-BRUVS) in surveying shark distribution comparing them to underwater visual censuses (UVC) and to evaluate their potential improvements ; 3) to evaluate the impact of human proximity on diversity, abundance and behaviour of reef sharks and 4) to determine the efficiency of management measures currently in place in New Caledonia to protect reef shark populations. The results of S-BRUVS and UVC were congruent and revealed a dramatic decline of shark abundance of ~90% along the anthropogenic gradient in a country where shark fishing is historically absent. An important behavioural alteration of the grey reef shark (Carcharhinus amblyrhynchos) towards bait was highlighted. Individuals remained farther from the device, exhibited more cautious approaches, interacted less with the bait and took longer to bite it as human proximity increased. Human proximity was the main driver of the abundance decline (46 to 71%) and the behavioural alteration towards shier individuals (50 to 80%). Globally, MPAs in New Caledonia are not effective in protecting reef sharks. However, the oldest and most restrictive MPA (Merlet) hosts shark abundance close to that of some remote reefs of the archipelago and partially protect the behaviour of individuals. These results 1) emphasize the unique role of remote coral reefs as the last refuges for sharks ; 2) reveal that in absence of shark fishing, human proximity condition shark abundance and behaviour with potential ecological consequences and 3) indicate that the MPAs efficiency to ensure the protection of reef sharks is effected by their ability to exclude human presence over a sufficiently large area
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Burgess, JoColl Alexis. „3D analysis of apical dendritic organization in the prefrontal cortex of young and old monkey“. Thesis, 2018. https://hdl.handle.net/2144/31219.
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Its known that the age-related decline in cognitive facilities is not due to the loss of neurons but more subtle changes in specific areas of the brain. Structural and morphological changes in cellular alignment in the minicolumns correlate with increased prevalence of neurological diseases and in aging. In the rhesus monkey, cognitive decline is similar to what humans experience in aging. In the monkey prefrontal cortex, Brodmann area 46, an important region for executive functioning, cognitive decline correlates with changes in cellular alignment or “columnar strength” as studies by Cruz et al., (2009). Using the density maps method in Area 46, the ventral bank was identified to be the most susceptible to structural changes. Minicolumns, are defined by the cellular alignment of neurons in the cortex and some believe that the dendritic bundles of neurons in the cortex is also considered an integral part of the columns. The functional role of apical dendrites, is not well understood, however, given the that repeated organized bundles transverse through the laminae could be further support for their inclusion in minicolumns with possible functional importance. If structural changes such as loss of columnar strength (neuronal displacement) that correlates with cognitive aging, it is possible that the dendritic organization may also be affected in this area. In this thesis, it is hypothesized that the dendritic bundles in this area could also be related to the cognitive deficits associated with normal aging. Using double- fluorescence labeling for dendrites (MAP-2) and neurons (Neu-N), 3D confocal reconstructions of the dorsal and ventral banks of Area 46 were used to investigate structural/morphological changes in the dendritic bundles in young and old rhesus monkeys. While cortical thickness and apical dendritic length between both banks did not change, we found a significant increase in inter-bundle spacing at layer 6A in the older monkeys in the ventral bank. Inter-bundle spacing for bundles in layer 5 was measured and showed that the young consistently have smaller inter-bundle spacing. Future studies with larger sample size will also investigate whether changes in dendritic bundles and their organization also correlate with age-related cognitive deficits.
Bücher zum Thema "Apical area"
1
Participatory, Monitoring and Evaluation in SPBCP Conservation Areas Workshop (1996 Apia Western Samoa). Participatory Monitoring and Evaluation in SPBCP Conservation Areas Workshop report, 2-5 December 1996 Apia, Western Samoa. Apia, Western Samoa: South Pacific Regional Environment Programme, 1998.
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2
Secretariat of the Pacific Community. Conference. Report of the 5th meeting of the Conference of the Pacific Community, Apia, Samoa, 12-13 November 2007. Noumea, New Caledonia]: Secretariat of the Pacific Community, 2007.
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3
Murer, Heini, Jürg Biber und Carsten A. Wagner. Phosphate homeostasis. Herausgegeben von Robert Unwin. Oxford University Press, 2015. http://dx.doi.org/10.1093/med/9780199592548.003.0025.
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Inorganic phosphate ions (H2PO4−/ HPO42−) (abbreviated as Pi) are involved in formation of bone and generation of high-energy bonds (e.g. ATP), metabolic pathways, and regulation of cellular functions. In addition, Pi is a component of biological membranes and nucleic acids. Only about 1% of total body Pi content is present in extracellular fluids, at a plasma concentration in adults within the range 0.8–1.4 mMol/L (at pH 7.4 mostly as HPO42−), with diurnal variations of approximately 0.2 mM. A small amount of plasma Pi is bound to proteins or forms complexes with calcium. Under normal, balanced conditions, absorption of dietary Pi along the small intestine equals the output of Pi via kidney and faeces. Renal excretion of Pi represents the key determinant for the adjustment of normal Pi plasma concentrations. Renal reabsorption of Pi occurs along the proximal tubules by sodium-dependent Pi cotransporters that are strictly localized at the apical brush border membrane. Parathyroid hormone (PTH) and FGF23 are key regulators amongst a myriad of factors controlling excretion of Pi in urine, mostly by changes of the apical abundance of Na/Pi cotransporters. Hypophosphataemia may result in osteomalacia, rickets, muscle weakness, and haemolysis. Hyperphosphataemia can lead to hyperparathyroidism and severe calcifications in different tissues.
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Llarich, Kyle W. Cardiac Examination, Valvular Heart Disease, and Congenital Heart Disease. Oxford University Press, 2012. http://dx.doi.org/10.1093/med/9780199755691.003.0042.
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Despite tremendous technologic advances in medical testing and imaging, physicians must be able to assess patients accurately at the bedside; this assessment allows appropriate, cost-effective, and efficient ordering of tests. Part I of this chapter outlines the salient features of a thorough physical examination, cardiac imaging techniques, and valvular and congenital heart disease. A thorough physical examination includes assessment of jugular venous pressure, arterial pulses, apical impulses, additional cardiac palpitations, and appropriate imaging techniques. Cardiac imaging techniques include contrast angiography, echocardiography, radionuclide imaging, magnetic resonance imaging, electron beam computed tomography and positron emission tomography. Different types of valvular and congenital heart disease are examined.
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Action strategy for protected areas in the South Pacific region: Prepared during the Third South Pacific National Parks and Reserves Conference, Apia, Western Samoa, 24 June-3 July, 1985. Noumea, New Caledonia: South Pacific Commission, 1985.
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6
Beattie, R. Mark, Anil Dhawan und John W.L. Puntis. Cystic fibrosis-associated liver disease. Oxford University Press, 2011. http://dx.doi.org/10.1093/med/9780198569862.003.0022.
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Pathophysiology 162Clinical features 162Diagnosis 163Management 164Cystic fibrosis (CF) is an autosomal recessive disease resulting from mutations in the gene coding for the cystic fibrosis transmembrane conductance regulator (CFTR) (see Chapter 21). CFTR functions as a transmembrane chloride channel in the apical membrane of most secretory epithelia and the disease thus affects lungs, pancreas, exocrine glands, gut, and liver. In CF-associated liver disease the biliary tract is most commonly involved in a spectrum from asymptomatic to biliary cirrhosis. The liver disease runs from mild and subclinical to severe cirrhosis and portal hypertension. Clinical disease is seen in 4–6% of cases, but there are biochemical abnormalities in 20–50%. At autopsy, fibrosis is present in 20% and steatosis in 50%....
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Cortes, Eduardo, Mohammed Belal, Arun Sahai und Roland Morley. Pelvic organ prolapse. Herausgegeben von Christopher R. Chapple. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780199659579.003.0039.
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Pelvic organ prolapse (POP) is a common condition in women. It is defined as a downward descent of pelvic organs through or at the introitus. Symptoms relate to the prolapse itself and its potential effects on the bowel and urinary systems. Careful assessment is required and all compartments of the vagina need to be examined to assess for multicompartment POP. Several classification systems exist but the Baden Walker and POP-Q systems are commonly employed today. Several patient and surgical factors will influence the management. Conservative management involves pelvic floor exercises and the use of pessaries. Goals of surgery are to reconstruct and restore the pelvic anatomy, maintain, or restore normal bowel and bladder function, and maintain vaginal capacity for sexual intercourse, if desired. Surgery can be transvaginal or abdominal. This chapter will outline the anatomy, aetiology, presentation, and management of anterior, posterior, and apical compartment prolapse.
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Marlow, Heather, Hrsg. Evolutionary Development of Marine Larvae. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198786962.003.0002.
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Access to a growing number of marine invertebrates with genetic and genomic tools has broadened our understanding of the diversity of developmental mechanisms, informing our understanding of larval evolution by allowing the identification of shared or divergent programs for the formation of body plan patterning and organ formation. Two such genetic programs are the apical plate patterning network and the hox/parahox trunk and gut patterning network common to larval and adult forms, respectively. While mounting evidence supports an ancient origin at the base of the Bilateria for both adult and larval forms, it is clear that many distinct organs and structures have appeared independently and can be shifted between the larval and adult phase frequently. Future advances in our understanding of larval evolution are likely to emerge from exhaustive studies of marine invertebrate cell types by single-cell sequencing technologies and through the study of the genetic basis of the metamorphic transition.
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Bockenhauer, Detlef, und Robert Kleta. Approach to the patient with renal Fanconi syndrome, glycosuria, or aminoaciduria. Herausgegeben von Robert Unwin. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780199592548.003.0041_update_001.
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Up to 80% of filtered salt and water is returned back into the circulation in the proximal tubule. Several solutes, such as phosphate, glucose, low-molecular weight proteins, and amino acids are exclusively reabsorbed in this segment, so their appearance in urine is a sign of proximal tubular dysfunction. An entire orchestra of specialized apical and basolateral transporters, as well as paracellular molecules, mediate this reabsorption. Defects in proximal tubular function can be isolated (e.g. isolated renal glycosuria, aminoacidurias, or hypophosphataemic rickets) or generalized. In the latter case it is called the Fanconi–Debre–de Toni syndrome, based on the initial clinical descriptions. However, in clinical practice it is usually referred to as just the ‘renal Fanconi syndrome’. Severity of proximal tubular dysfunction can vary, and may coexist with some degree of loss of glomerular filtration capacity. Causes include a wide range of insults to proximal tubular cells, including a number of genetic conditions, drugs and poisons.
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Servais, Aude, und Bertrand Knebelmann. Cystinuria. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199972135.003.0024.
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Cystinuria (OMIM #220100) is an autosomal recessive disorder of a dibasic amino acid transport in the apical membrane of epithelial cells of the renal proximal tubule and small intestine. It leads to increased urinary cystine excretion and recurrent urolithiasis. The cystine transporter is an heterodimeric transporter which is composed of a heavy subunit, rBAT, linked to a light subunit, b0,+AT. Two genes, SLC3A1 (solute carrier family 3 member 1) and SLC7A9, coding for rBAT and b0,+AT, account for the genetic basis of cystinuria. Cystinuria may lead to obstruction, infections, and ultimately to renal insufficiency. The diagnosis of cystinuria mainly relies on stone analysis, urinary cystine measurement, or urinary cystine crystal identification. Medical treatment is based upon a stepwise strategy using hydration and alkalinization as basic measures, with the addition of thiol derivatives in refractory cases. Urological interventions are often indicated for the management of cystine stones >5 mm in diameter.
Buchteile zum Thema "Apical area"
1
Simon, Deepti. „Endodontic Surgery“. In Oral and Maxillofacial Surgery for the Clinician, 349–60. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-15-1346-6_16.
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AbstractEndodontic surgery straddles the specialties of endodontics and dento alveolar surgery. With the advent of the operating microscope, newer endodontic filling materials and stem cell therapy, humungous strides have been taken in this area, thus enabling transmutation of peri apical surgery into an avant-garde treatment modality, this chapter is a modest attempt to expound the various aspects of the subject from the surgeons frame of reference. Hence greater import is laid on incisions, flaps,surgical techniques, rather than restorative materials and retro cavity preparation.
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Gomez, Alberto, Mihaela Porumb, Angela Mumith, Thierry Judge, Shan Gao, Woo-Jin Cho Kim, Jorge Oliveira und Agis Chartsias. „Left Ventricle Contouring of Apical Three-Chamber Views on 2D Echocardiography“. In Simplifying Medical Ultrasound, 96–105. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-16902-1_10.
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AbstractWe propose a new method to automatically contour the left ventricle on 2D echocardiographic images. Unlike most existing segmentation methods, which are based on predicting segmentation masks, we focus at predicting the endocardial contour and the key landmark points within this contour (basal points and apex). This provides a representation that is closer to how experts perform manual annotations and hence produce results that are physiologically more plausible. Our proposed method uses a two-headed network based on the U-Net architecture. One head predicts the 7 contour points, and the other head predicts a distance map to the contour. This approach was compared to the U-Net and to a point based approach, achieving performance gains of up to 22% in terms of landmark localisation ($${<}4.5$$ < 4.5 mm) and distance to the ground truth contour ($${<}3.0$$ < 3.0 mm).
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DeJong, T. M. „The structure of trees.“ In Concepts for understanding fruit trees, 22–26. Wallingford: CABI, 2022. http://dx.doi.org/10.1079/9781800620865.0004.
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Abstract Trees are, by definition, the tallest land plants. To grow tall over multiple years they must solve several problems: structural strength; carbohydrate and nutrient storage capacity to survive and regrow after periods of stress; and conductive capacity for water, carbohydrates and nutrients must be increased/renewed over time to keep pace with increases in canopy size. Additionally, apical meristems must be capable of surviving through periods of stress (especially over winter or during drought). Structural strength, storage capacity and water, carbohydrate and nutrient conductive capacity are provided by cells derived from a sheath of meristematic cells (vascular cambium) that surround the body of trees (shoots, stems, branches, trunk, perennial roots). This chapter describes the structure of fruit trees.
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van der Linden, Frans P. G. M. „Autotransplantatie bij een klasse-II/1-afwijking met agenesie van een onderpremolaar en een terugliggende apicale area in de bovenkaak“. In Tandheelkundige casuïstiek, 431–39. Houten: Bohn Stafleu van Loghum, 2002. http://dx.doi.org/10.1007/978-90-313-8811-0_83.
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5
Jankowicz-Cieslak, Joanna, Florian Goessnitzer, Sneha Datta, Altus Viljoen, Ivan Ingelbrecht und Bradley J. Till. „Induced mutations for generating bananas resistant to Fusarium wilt tropical race 4.“ In Mutation breeding, genetic diversity and crop adaptation to climate change, 366–78. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789249095.0038.
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Abstract Bananas are a staple for more than 400 million people. Additionally, more than 16.5 million tonnes are exported, making it both an important food security and a cash crop. Productivity of Cavendish-type bananas is threatened by both abiotic and biotic stresses. The fact that triploid bananas are sterile, parthenocarpic and obligate vegetatively propagated makes them particularly susceptible to diseases, including Fusarium wilt caused by Fusarium oxysporum f. sp. cubense (Foc) tropical race 4 (Foc TR4). This is because continual clonal propagation has led to loss of genetic diversity. Additionally, lack of meiosis limits methods for breeding. Foc TR4 has been devastating Cavendish bananas in South-east Asia but has recently also been reported from Queensland in Australia, the Middle East and Mozambique, thus threatening global banana production. To address this, we are performing mutagenesis of in vitro propagated bananas to broaden the genetic diversity in order to find new alleles conferring disease resistance. We have developed methods for efficient induction of mutations in isolated apical meristems from shoot tips using chemical mutagens and ionizing radiation. Mutation discovery methods have been adapted to recover mutations including single point mutations and large deletions spanning millions of base pairs. We have created approximately 5000 mutated lines for forward-genetic screens to identify TR4 resistance in greenhouse- evaluated material. A subset of ca. 500 in vitro plantlets was subjected to glasshouse-based screening using a virulent F. oxysporum isolate. To date, 23 lines showing altered resistance responses to Foc TR4 have been identified.
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Spada, Stefania. „The Capability of ‘Models’ to Withstand Change The Bologna Area in the Wake of Law 132/2018“. In Stuck and Exploited Refugees and Asylum Seekers in Italy Between Exclusion, Discrimination and Struggles. Venice: Fondazione Università Ca’ Foscari, 2021. http://dx.doi.org/10.30687/978-88-6969-532-2/005.
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This essay aims to reflect about the impact of the recent Italian Law 132/2018 and its effects on the reception policies for asylum seekers in the area of the Metropolitan City of Bologna. Starting to the fact that the system of developed in Bologna is considered a model of excellence, this contribution aims to examine its ability to deal the erosion of rights for asylum seekers provided by recent legislation. Will the integrated territorial system of reception and services react to the restrictions in access and protection imposed by Law 132/2018? The contribution is intended to give back the evolutions of the territorial system, trying to bring out the ambiguities and the founding causes of the criticalities that have become structural. Is it appropriate to speak of a model? If so, with what risks arising from the bureaucratic action that characterises the system at the apical level? A last paragraph will also be dedicated to the effects of the COVID-19 pandemic on the territorial reception system, having affected the dynamics exposed in the essay.
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Martins, Adriana Vieira, Rodrigo de Castro Albuquerque, Lucas Moreira Maia, Hans Hatner Araujo Oliveira, Rodrigo Keigo Nakagawa, Luis Fernando dos Santos Alves Morgan, Nelson Renato França Alves Silva und Rodrigo Richard da Silveira. „Successful outcome of surgical reintervention for implant placement in borderline aesthetic area related to agenesis: a case report“. In DEVELOPMENT AND ITS APPLICATIONS IN SCIENTIFIC KNOWLEDGE. Seven Editora, 2023. http://dx.doi.org/10.56238/devopinterscie-071.
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The aim of this study is to illustrate and discuss the fundamentals of a well-succeeded and minimally invasive technique of surgical reintervention for installing implant in the reduced area of the alveolus, affected by agenesis, and traumatized by an unsuccessful intervention. Materials and methods: A 27-year-old patient sought dental care and her main cause was the great dissatisfaction with the aesthetic sequelae in the region of the right upper lateral incisor, in addition to the uncertainty regarding the predictability of a new unitary implant. Imaging exams showed trauma in the middle and apical region of the canine root surface. The dimensions of the edentulous area varied between 4.6 and 5.52 mm. A small diameter implant (BLT 2.9mm SC, Loxim SLActive® 12 mm, TiZr - Straumann Dental Implant System) was planned and installed, in addition to a subepithelial connective graft. Results: The results achieved allowed to restore the desired function and aesthetics, with excellence, low morbidity, in addition to a predictability favored by the benefits related to small diameter implants. Conclusions: The concept of minimally invasive dentistry is becoming an effective surgical approach and, although these implants present a higher risk for fracture than do large-diameter implants, implant fractures are rarely observed.
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Whitworth, John. „Prevention of pulpal and periapical disease“. In The Prevention of Oral Disease, 97–112. Oxford University PressNew York, NY, 2003. http://dx.doi.org/10.1093/oso/9780192632791.003.0006.
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Abstract Apical periodontitis is a term to describe inflammatory conditions of the periodontal tissues that are caused by irritants in the pulp canal system. While the majority of these lesions develop around root apices, apical periodontitis can occur laterally or in furcal regions, associated with any natural or pathological communication between the pulp space and the periodontium.
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Marmion, Doug. „Wajarri“. In The Oxford Guide to Australian Languages, 933–49. Oxford University PressOxford, 2023. http://dx.doi.org/10.1093/oso/9780198824978.003.0077.
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Abstract This chapter presents an introduction to Wajarri, a Pama-Nyungan language from the Murchison-Gascoyne region of Western Australia. Wajarri is a typical Western Australian Pama-Nyungan language, having a fairly free word order and a suffixing, agglutinative structure. It has a split-ergative case marking system and an incomplete set of bound pronouns which encliticise to the first clausal constituent. Wajarri has two open verb conjugation classes and a small set of irregular verbs, which inflect for tense, aspect and mood. Additionally it shows a switch-reference system that applies to certain subordinate clause types. The phonemic inventory has six places of articulation for consonants, with both a laminal and apical contrast, and three vowels. Wajarri traditional country extends across a large area and has a number of named varieties, which vary primarily in lexicon.
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Hinton, Barry T., und Terry T. Turner. „The Seminiferous Tubular Microenvironment“. In Cell And Molecular Biology Of The Testis, 238–65. Oxford University PressNew York, NY, 1993. http://dx.doi.org/10.1093/oso/9780195062694.003.0011.
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Abstract Although we often speak of the seminiferous tubular microenvironment as if it were a singular thing, in reality the tubules are surrounded by and contain a series of microenvironments, each playing a necessary role in the development of spermatozoa. The developing germ cell is faced with several different microenvironments within the seminiferous epithelium and another that bathes the luminal spermatozoa and apical membranes of Sertoli cells. Even this latter microenvironment may change from one area of the tubular lumen to another and may exert different influences on germ cells or Sertoli cells along the way. Knowledge of seminiferous tubule physiology is now much more extensive than it was 20 years ago when specific studies of the intratubular microenvironment began (Tuck et al., 1970; Levine and Marsh, 1971); nevertheless, much of what is presently known about the seminiferous microenvironment is still limited to the microenvironment in the seminiferous tubule lumen. For example, we know much less about the microenvironment surrounding the developing germ cells within the seminiferous epithelium. The knowledge that is developing within this latter area comes primarily from cell biological studies, and this discussion attempts to integrate these developments with what is known about the physiology of the testicular parenchyma.
Konferenzberichte zum Thema "Apical area"
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Manikovskaya, N. S., und L. V. Nacheva. „ON THE SEVERTSOV-PLATE FUNCTION INTENSIFICATION PRINCIPLE BY THE EXAMPLE OF THE INTESTINES OF HEPATIC TREMATODE PARAFASCIOLOPSIS FASCIOLAEMORPHA EJSMONT, 1932 (PLATHELMINTHES, TREMATODA)“. In THEORY AND PRACTICE OF PARASITIC DISEASE CONTROL. All-Russian Scientific Research Institute for Fundamental and Applied Parasitology of Animals and Plant – a branch of the Federal State Budget Scientific Institution “Federal Scientific Centre VIEV”, 2023. http://dx.doi.org/10.31016/978-5-6048555-6-0.2023.24.285-289.
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The study considers morphological and functional features of the intestine of
the trematode Parafasciolopsis fasciolaemorpha in the context of its endostation,
namely, the bile ducts in the liver of the moose Alces alces (1st order environment),
which reveal mechanisms that ensure the parasite adaptation. The intestine of P.
fasciolaemorpha is covered with epithelium, while its apical part is represented by thin
microvilli, and the basal part contains nuclei and reticular cytoplasm. The epithelium
is delimited from parenchyma by a basal membrane of a collagenous nature. Intense
bromphenolophilia and toluidinophilia manifested at the apical end of the microvilli
indicate the accumulated glycoproteins and involvement in the breakdown of food, as
well as in the increase in the enterocyte resistance to antigenic effects of the host and
the manifestation of anticoagulant properties. Enterocytes function in analogy with
microapocrine secretion, and digestion is mainly parietal (and partially abdominal). The microvilli in the apical part of the intestinal epithelium increase the working
surface area and accelerate the processes of parietal digestion with enhancing the
trophic processes of the helminth P. fasciolaemorpha to survive in the host organism,
which helps small parasites to adapt in the endostation. The study results serve as a
clear illustration of the Severtsov-Plate function intensification principle.
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Gao, Ling, Max Mandelbaum, Nicholas Liaw, Sabareesh K. Natarajan, J. Mocco, Adnan H. Siddiqui, Hui Meng und John Kolega. „Early Cellular and Molecular Changes During Hemodynamic Initiation of Intracranial Aneurysms in a Rabbit Model“. In ASME 2010 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2010. http://dx.doi.org/10.1115/sbc2010-19598.
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Hemodynamics constitutes a critical factor in the formation of intracranial aneurysms. However, little is known about how an intracranial arterial wall responds to a hemodynamic insult, and how that response contributes to aneurysm formation. Unlike straight arterial segments (which respond to increased flow by expansive remodeling) and sinuses opposing bifurcation apices (which harbor recirculation flows and are prone to atherosclerotic development), aneurysmal degeneration occurs on the apical side of the bifurcation in the immediate peri-apical region, where flow creates very high wall shear stress (WSS) and wall shear stress gradient (WSSG)1. This results in destructive aneurysmal remodeling, characterized by loss of the internal elastic lamina (IEL) and thinning of the media. It is unknown how the unique hemodynamic conditions of combined high WSS and positive WSSG elicit these morphological changes, how the vascular wall responds to such insult at the molecular level, and what molecular mechanisms are involved.
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Janes, Gregory, Tikran Kocharian und Sanjivan Manoharan. „Numerical Investigation of Irrigant Flow Characteristics for Manual Endodontic Debridement“. In ASME 2022 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/imece2022-95982.
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Abstract Root canal therapy or endodontic treatment is a nonsurgical approach used to remove the infected pulp, disinfect, and reshape the canal. Despite more than a century of technological improvements in root canal procedures, clinical studies indicate that microbial flora remain in the canal following standardized cleaning and shaping procedures using antimicrobial irrigants. Unfortunately, accessing this ‘dead zone’ in the apical third has been challenging given the large number of parameters that govern the flow pattern. Computational fluid dynamics (CFD) presents a powerful tool to investigate flow behavior in areas where experimental measurements are difficult to perform. This paper is divided into two sections. First, the influence of irrigant flow rate and needle insertion depth on velocity characteristics are computationally investigated for a simplified root geometry. The needle type considered is a 30 gage KerrHawe with a side vent for fluid discharge. The simplified root canal was modeled as a frustum with a length of 18 mm, diameter of 1.59 mm at the orifice, and a diameter of 0.45 mm at the apical constriction (6.5% taper). Following this, a more realistic root geometry is used to investigate how the results from part 1 scale with root geometry.
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Guo, Peng, Stanley D. Hillyard und Bingmei M. Fu. „Water Flux Coupled to Active Solute Transport Across Amphibian Epidermis“. In ASME 2003 Heat Transfer Summer Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/ht2003-47207.
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We examine the water flux across amphibian skin driven by both the osmotic gradient and the active transport. Amphibian skin is modeled as a well-stirred compartment bounded by a mucosal barrier and a serosal barrier. The compartment represents the lateral intercellular space between cells in the stratum granulosum. The mucosal barrier is comprised of a cell barrier and a tight junctional barrier. The cell barrier is hypothesized to have the ability to actively transport solute (Na-K-ATPase) and the solute flux is assumed to satisfy the Machaelis-Menton relationship. Our model shows that: 1) there is a substantial water flux coupled to the active solute flux and this coupled water flux is nearly constant when the osmolality of the apical bathing solution is greater than 100 mOsm despite its variation; 2) the predicted rehydration rates from apical bathing solutions are in good agreement with the experiment results in Hillyard and Larsen [2]; 3) the molar ratio of the actively transported solute flux to the coupled water flux is 1:165, which is almost the same as that reported in Nielsen [5].
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Tabara, Maria, Nina Ciorchina und Mariana Trofim. „Perspectivele microclonării și micropropagării speciei Rosa canina L.“ In VIIth International Scientific Conference “Genetics, Physiology and Plant Breeding”. Institute of Genetics, Physiology and Plant Protection, Republic of Moldova, 2021. http://dx.doi.org/10.53040/gppb7.2021.46.
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Rosehip fruits are characterized by high concentrations of vitamin C and antioxidants, which we can say that rosehip is a reservoir of vitamins for the human body. The aim of this study is to improve the in vitro propagation efficiency of this valuable plant species. In this study, apical buds were inoculated on 100% MS medium supplemented with BAP of 0.5-1.0 mg/l and FeNaEDDHA 50 mg/l - Sequestrene 138, to avoid the phenomenon of leaf chlorosis. Due to the multiple characteristics, Rosa canina is of practical interest for our country, which leads to the need to produce propagating material through in vitro culture.
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Pedrigi, Ryan M., Ritika Gupta, Sietse T. Braakman, W. Daniel Stamer, C. Ross Ethier und Darryl R. Overby. „Pore Formation in Schlemm’s Canal Endothelial Cells Is Mechano-Sensitive and Impaired in Glaucoma“. In ASME 2012 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/sbc2012-80713.
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Increased intraocular pressure (IOP) is the leading risk factor for glaucoma, but the mechanisms of IOP regulation during normalcy and disease are poorly understood. Considerable evidence suggests that Schlemm’s canal (SC) endothelial cells may influence IOP by regulating aqueous humor outflow via the formation of trans-endothelial pores. This study employs a biomimetic perfusion system to explore pore formation in SC cells in vitro. Our results show that pore formation increases with increasing pressure drop, occurs only when flow is directed basal-to-apical across the cell layer, and it is reduced in glaucomatous versus normal SC cell lines. These results suggest that pore formation is a biomechanically regulated process and they establish our system as the first in vitro model that captures a specific pathology associated with glaucoma.
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Menon, Prahlad G., und Srilakshmi M. Adhyapak. „Shape Analysis for Automatic and Objective Visualization of Pathological Cardiovascular Remodeling From Cine Cardiac MRI“. In ASME 2013 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/sbc2013-14078.
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Normal cardiovascular tissue structure and therefore shape is governed by an equilibrium existing between stimulator and inhibitor signals that regulate growth and remodeling [1]. Characterization of left ventricular (LV) remodeling following an insult or major adverse cardiac event that disturbs this balance (eg: transmural myocardial infarction) can provide crucial information to guide non-transplant therapeutic options for improving cardiac function or surgical restoration of ventricular shape. In this study, analysis of endocardial morphology and function in remodeled LV territories is presented in the context of front-line quantitative 4D (3D + time) assessment of an antero-apical LV aneurysm in a 42 year old male patient from cine cardiac MRI data. In this regard, two promising shape analysis techniques are discussed: a) Hausdorff distance; and b) weighted spherical harmonics (SPHARM).
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Inoue, Masato, und Yoshiyuki Matsuoka. „Form-Generation System for Obtaining Diverse Design Solutions Supporting Early Process of Design in Structural Design“. In ASME 2003 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/detc2003/dtm-48670.
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Conventional structural optimization methods are difficult to apply to the early process of design referred to as conceptual design, in which diverse design solutions are to be obtained. This paper described a design method that obtains diverse design solutions. As a first step, a form-generation system that generates diverse forms is proposed. In this case, the diversity of organism was noted, and the form-generation method was referred to ‘induction’ and ‘apical dominance’ in the developmental process of organism. The proposed system, consisting of a generation process and an optimization process, was applied to the structural design of chairs, and the diversity of solutions was analyzed. As a result, it is shown that, as compared with conventional structural optimization methods, the proposed method obtains design solutions of adequate diversity. The results indicate the effectiveness of the proposed system for obtaining diverse design solutions.
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Chang, Shyy Woei, Tong-Minn Liou, Shyr Fuu Chiou und Shuen Fei Chang. „High Rotation Number Heat Transfer of Rotating Trapezoidal Duct With 45-deg Staggered Ribs and Bleeds From Apical Side Wall“. In ASME Turbo Expo 2007: Power for Land, Sea, and Air. ASMEDC, 2007. http://dx.doi.org/10.1115/gt2007-28174.
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An experimental study of heat transfer in a radially rotating trapezoidal duct with two opposite walls roughened by 45° staggered ribs and mid-rib bleeds from the apical side wall is performed. Centerline heat transfer variations on two rib-roughened surfaces are measured for radially outward flows with and without bleeds at test conditions of Reynolds number (Re), rotation number (Ro) and density ratio (Δρ/ρ) in the ranges of 15000–30000, 0–0.8 and 0.04–0.31, respectively. Geometrical configurations and rotation numbers tested have considerably extended the previous experiences that offer practical applications to the trail edge cooling of a gas turbine rotor blade. A selection of experimental data illustrates the individual and interactive influences of Re, Ro and buoyancy number (Bu) on local heat transfer with and without bleeds. Local heat transfer results are generated with the influences of sidewall bleeds examined to establish heat transfer correlations with Re, Ro and Bu as the controlling flow parameters for design applications.
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Yang, Jui-Ming, und Philip R. LeDuc. „Three-Dimensional Laminar Flow for Localized Cellular Stimulation“. In ASME 2004 International Mechanical Engineering Congress and Exposition. ASMEDC, 2004. http://dx.doi.org/10.1115/imece2004-61643.
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Stimulation of living mammalian cells is primarily accomplished by the delivery of chemical agents to single cells or cell populations. Due to the fast response time of diffusion for these agents over the small size scale of individual cells, localized stimulation is limited. Currently, there are alternate techniques that can produce localized gradients of chemical stimulants over single cells, but they lack the ability for long time scale events that are requisite for many cellular processes because of this diffusion limitation. We have developed a device that is able to create chemical agent separation in three dimensions along distinct boundaries that can be applied to cells. As many techniques are two-dimensionally constrained, this provides us with a more physiologically relevant system for investigating cellular signal transduction and can allow basal to apical activation separations. To accomplish this, multiple flow paths were introduced to manipulate spatiotemporally distinct regions inside a single capillary channel. Solutions that flow laminarly inside these fluidic channels deliver predefined chemicals to specific locations without turbulent mixing. Separation using this system under laminar flows created not only side by side domains in this capillary but also vertical as well. This device has multiple potential applications both in cell and molecular biology as well as in fluid dynamics and fabrication processes.
Berichte der Organisationen zum Thema "Apical area"
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Eshed-Williams, Leor, und Daniel Zilberman. Genetic and cellular networks regulating cell fate at the shoot apical meristem. United States Department of Agriculture, Januar 2014. http://dx.doi.org/10.32747/2014.7699862.bard.
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The shoot apical meristem establishes plant architecture by continuously producing new lateral organs such as leaves, axillary meristems and flowers throughout the plant life cycle. This unique capacity is achieved by a group of self-renewing pluripotent stem cells that give rise to founder cells, which can differentiate into multiple cell and tissue types in response to environmental and developmental cues. Cell fate specification at the shoot apical meristem is programmed primarily by transcription factors acting in a complex gene regulatory network. In this project we proposed to provide significant understanding of meristem maintenance and cell fate specification by studying four transcription factors acting at the meristem. Our original aim was to identify the direct target genes of WUS, STM, KNAT6 and CNA transcription factor in a genome wide scale and the manner by which they regulate their targets. Our goal was to integrate this data into a regulatory model of cell fate specification in the SAM and to identify key genes within the model for further study. We have generated transgenic plants carrying the four TF with two different tags and preformed chromatin Immunoprecipitation (ChIP) assay to identify the TF direct target genes. Due to unforeseen obstacles we have been delayed in achieving this aim but hope to accomplish it soon. Using the GR inducible system, genetic approach and transcriptome analysis [mRNA-seq] we provided a new look at meristem activity and its regulation of morphogenesis and phyllotaxy and propose a coherent framework for the role of many factors acting in meristem development and maintenance. We provided evidence for 3 different mechanisms for the regulation of WUS expression, DNA methylation, a second receptor pathway - the ERECTA receptor and the CNA TF that negatively regulates WUS expression in its own domain, the Organizing Center. We found that once the WUS expression level surpasses a certain threshold it alters cell identity at the periphery of the inflorescence meristem from floral meristem to carpel fate [FM]. When WUS expression highly elevated in the FM, the meristem turn into indeterminate. We showed that WUS activate cytokinine, inhibit auxin response and represses the genes required for root identity fate and that gradual increase in WUCHEL activity leads to gradual meristem enlargement that affect phyllotaxis. We also propose a model in which the direction of WUS domain expansion laterally or upward affects meristem structure differently. We preformed mRNA-seq on meristems with different size and structure followed by k-means clustering and identified groups of genes that are expressed in specific domains at the meristem. We will integrate this data with the ChIP-seq of the 4 TF to add another layer to the genetic network regulating meristem activity.
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McElwain, Terry F., Eugene Pipano, Guy H. Palmer, Varda Shkap, Stephn A. Hines und Wendy C. Brown. Protection of Cattle against Babesiosis: Immunization against Babesia bovis with an Optimized RAP-1/Apical Complex Construct. United States Department of Agriculture, September 1999. http://dx.doi.org/10.32747/1999.7573063.bard.
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Previous research and current efforts at control of babesiosis fall short of meeting the needs of countries where the disease is endemic, such as Israel, as well as the needs of exporting countries and countries bordering on endemic areas, such as the U.S. Our long-term goal is to develop improved methods of immunization against bovine babesiosis based on an understanding of the molecular mechanisms of immune protection and parasite targets of a protective immune response. In our previous BARD project, we established the basis for focusing on rhoptry antigens as components of a subunit vaccine against bovine babesiosis, and for additional research to better characterize rhoptry associated protein-1 (RAP-1) as a target of protective immunity. In this continuation BARD project, our objectives were to [1] optimize the immune response against RAP-1, and [2] identify additional rhoptry candidate vaccine antigens. The entire locus encoding B. bovis RAP-1 was sequenced, and the rap-1 open reading frame compared among several strains. Unlike B. bigemina, in which multiple gene copies with variant domains encode RAP-1, the B. bovis RAP-1 locus contains only two identical genes which are conserved among strains. Through testing of multiple truncated constructs of rRAP-1, one or more immunodominant T cell epitopes were mapped to the amino terminal half of RAP-1. At least one linear and one conformational B cell epitope have been demonstrated in the same amino terminal construct, which in B. bigemina RAP-1 also contains an epitope recognized by neutralizing antibody. The amine terminal half of the molecule represents the most highly conserved part of the gene family and contains motifs conserved broadly among the apicomplexa. In contrast, the carboxy terminal half of B. bovis RAP-1 is less well conserved and contains multiple repeats encoding a linear B cell epitope potentially capable of inducing an ineffective, T cell independent, type 2 immune response. Therefore, we are testing an amino terminal fragment of RAP-1 (RAP-1N) in an immunization trial in cattle. Cattle have beer immunized with RAP-1N or control antigen, and IL-12 with Ribi adjuvant. Evaluation of the immune response is ongoing, and challenge with virulent B. bovis will occur in the near future. While no new rhoptry antigens were identified, our studies did identify and characterize a new spherical body antigen (SBP3), and several heat shock proteins (HSP's). The SBP3 and HSP21 antigens stimulate T cells from immune cattle and are considered new vaccine candidates worthy of further testing. Overall, we conclude that a single RAP-1 vaccine construct representing the conserved amino terminal region of the molecule should be sufficient for immunization against all strains of B. bovis. While results of the ongoing immunization trial will direct our next research steps, results at this time are consistent with our long term goal of designing a subunit vaccine which contains only the epitopes relevant to induction of protective immunity. Parallel studies are defining the mechanisms of protective immunity. Apicomplexan protozoa, including babesiosis and malaria, cause persistent diseases for which control is inadequate. The apical organelles are defining features of these complex protozoa, and have been conserved through the evolutionary process, Past and current BARD projects on babesiosis have established the validity and potential of exploiting these conserved organelles in developing improved control methods applicable to all apicomplexan diseases.
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McElwain, Terry, Eugene Pipano, Guy Palmer, Varda Shkap, Stephen Hines und Douglas Jasmer. Protection of Cattle Against Babesiosis: Immunization with Recombinant DNA Derived Apical Complex Antigens of Babesia bovis. United States Department of Agriculture, Juni 1995. http://dx.doi.org/10.32747/1995.7612835.bard.
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Bovine babesiosis caused by Babesia bovis continues to be a significant deterrent to global livestock production. Current control methods have both biological and technical drawbacks that have stimulated research on improved methods of vaccination. This BARD project has focused on characterization of candidate Babesia bovis vaccine antigens located in the apical complex, a unique group of subcellular organelles - including rhoptries, micronemes, and spherical bodies - involved in the invation of erythrocytes. Spherical bodies and rhoptries were partially purified and their contents characterized using monoclonal antibodies. Existing and newly developed monoclonal antibodies bound to antigens in the spherical body, rhoptry, merozoite membrane, and infected erythrocyte membrane. In an initial immunization study using biologically cloned strains, it was demonstrated that strain-common epitopes are important for inducing immune protection against heterologous challenge. Rhoptry-associated antigen 1 (RAP-1) had been demonstrated previously to induce partial immune protection, fulfilled criteria of broad interstrain B and T cell epitope conservation, and thus was further characterized. The RAP-1 gene family consists of at least two gene copies, is homologous to the RAP-1 gene family in B. bigemina, and contains significant sequence similarity to other erythroparasitic protozoan candidate vaccine antigens, including the apical membrane antigen of Plasmodium falciparum. A new RAP-1 monoclonal antibody was developed that inhibits merozoite growth in vitro, demonstrating the presence of a RAP-1 neutralization sensitive domain. Based on these observations, cattle were immunized with Mo7 (Mexico) strain recombinant RAP-1 representing one of the two gene copies. All cattle responded with variable levels of serum antibodies inhibitory to heterologous Israel strain merozoite growth in vitro, and RAP-1 specific T lymphocytes that proliferated when stimulated with either homologous or heterologous native parasite antigen. Minimal protection from clinical disease was present after virulent Israel (heterologous) strain B. bovis challenge. In total, the results support the continued development of RAP-1 as a vaccine antigen, but indicate that additional information about the native structure and function of both RAP-1 gene copies, including the relationship of conserved and polymorphic sequences to B and T cell lepitopes relevant for protection, is necessary for optimization of RAP-1 as a vaccine component.
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Eshed, Yuval, und Sarah Hake. Shaping plant architecture by age dependent programs: implications for food, feed and biofuel. United States Department of Agriculture, Dezember 2012. http://dx.doi.org/10.32747/2012.7597922.bard.
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Age dependent programs are responsible for the physiological and developmental differences of young and mature plants. These include a range of morphological characters such as leaf shape and leaf composition (waxes, lignin etc..) but also different in developmental potentials. Apical buds of juvenile plants are vegetative, while those of mature plants can be reproductive. Likewise, basal buds form in the axills of juvenile leaves have different fates than distal buds formed in the axils of mature leaves. The goal of our joint project is to understand and exploit theses age related programs for specific improvement of crop plants. To that end both the WIS group and the PGEC group are using mutants with age related defects as well as modified expression of miR156 to modify age related programs in crop plants- Tomato and potato in Israel and Maize, switchgrass and Brchipodium in the US. In the US, major effort were made to: Characterize the contribution of selected miR156 target genes to yield component traits of maize. Functional analysis of microRNAs and their targets in new crop plants. In Israel, the research progressed in several directions: Understanding the interplay between age dependent programs and the potential of tomato and potato meristems to produce tubers. Evaluation of the agronomic value of mutants that alter flowering regime in side shoots in general, and in the sympodial buds in particular Characterization of wild type axillary buds, comparing shoot ontogeny of gradually maturing apices from basal and distal positions along the main shoot of tomato.
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Dimitrova, Violeta S., Vanyo I. Mitev und Antonia R. Isaeva. The α and β Subunits of CK2 Are Individually and Phenotypespecifically Involved in Autocrine and BMP4‑Triggered Regulation of Proliferation of STRO‑1+, STRO‑1-, CD105+ and CD105- Cells within Human Apical Papilla. "Prof. Marin Drinov" Publishing House of Bulgarian Academy of Sciences, Dezember 2020. http://dx.doi.org/10.7546/crabs.2020.12.07.
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Venton, Philip, und Gianluca Mannucci. JTM16-VM The APIA Method of Designing Against Prenetration. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), April 2007. http://dx.doi.org/10.55274/r0011797.
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The 1997 revision of the Australian Standard for design and construction of gas and liquid petroleum pipelines required each pipeline to be designed to control external interference through a combination of physical and procedural methods. However it did not provide guidance on how to judge when control by resistance to penetration was effective in controlling an identified external interference threat. In developing a revision to the Standard, the responsible committee focussed on developing a soundly research based set of rules that would ensure that the industry adopted a common approach to penetration resistance when applied as a physical control of external interference. This was intended to ensure that a minimum standard for external interference can be relied on for each pipeline. Notwithstanding considerable research effort both in Australia and overseas, the conclusion drawn, (and reported to this JTM in 2005) was so conservative that it was unreasonable and unacceptable, particularly when its application was mandatory. Analysis of data from "real" excavators has provided a rational basis for the committee to revise the approach and incorporated requirements for resistance to penetration which, when used with a combination of multiple and independent physical and procedural controls are considered to be sufficient to reduce the risk of pipeline failure to an acceptable level.
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Marlow, Thomas. PR-000-18COMP-R03 Damage Prevention Compendium. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), Januar 2019. http://dx.doi.org/10.55274/r0011548.
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The PRCI Technical Committees have carried many research projects related to the subject of Damage Prevention. This report; therefore, presents a summary of past PRCI-funded studies in the area of Damage Prevention. Since studies sponsored by other industry groups (e.g., INGAA, EPRG, APIA, CEPA, etc.) or by individual pipeline companies are not included, this report does not represent a review of the topic in the broader industry-wide sense. Instead, it is designed to provide a guide to past work so that current TC members can identify and locate project reports that might be of use in addressing their current day-to-day damage prevention issues.
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Choquette, Gary. PR-000-21COMP-R09 Weld Seam Corrosion Compendium. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), September 2021. http://dx.doi.org/10.55274/r0012150.
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The PRCI Technical Committees have carried multiple research projects related to the subject of weld seam corrosion. This report, therefore, presents a summary of past PRCI funded studies in the area of weld seam corrosion. Since not all studies sponsored by other industry groups (e.g., INGAA, EPRG, APIA, CEPA, etc.) or by individual pipeline companies are not included, this report does not represent a review of the topic in the broader industry-wide sense. Instead, it is designed to provide a guide to past work so that current TC members can identify and locate project reports that might be of use in addressing weld seam corrosion issues.
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Greaney, Carrie. PR-000-18COMP-R04 Geohazards Compendium. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), Januar 2019. http://dx.doi.org/10.55274/r0011549.
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The PRCI Technical Committees have carried many research projects related to the subject of Geohazards. This report; therefore, presents a summary of past PRCI-funded studies in the area of Geohazards. Since studies sponsored by other industry groups (e.g., INGAA, EPRG, APIA, CEPA, etc.) or by individual pipeline companies are not included, this report does not represent a review of the topic in the broader industry-wide sense. Instead, it is designed to provide a guide to past work so that current TC members can identify and locate project reports that might be of use in addressing their current day-to-day Geohazard issues.
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Marlow, Thomas, Laurie Perry (Archived) und Carrie Greaney. PR-000-18COMP-R05 Horizontal Directional Drilling Compendium. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), Januar 2019. http://dx.doi.org/10.55274/r0011550.
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The PRCI Technical Committees have carried many research projects related to the subject of horizontal directional drilling (HDD). This report; therefore, presents a summary of past PRCI-funded studies in the area of HDD. Since studies sponsored by other industry groups (e.g., INGAA, EPRG, APIA, CEPA, etc.) or by individual pipeline companies are not included, this report does not represent a review of the topic in the broader industry-wide sense. Instead, it is designed to provide a guide to past work so that current TC members can identify and locate project reports that might be of use in addressing their current day-to-day HDD issues.