Journal articles on the topic 'Regenerative Sampling'
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MÖHLE, MARTIN. "On a Class of Non-Regenerative Sampling Distributions." Combinatorics, Probability and Computing 16, no. 03 (November 3, 2006): 435. http://dx.doi.org/10.1017/s0963548306008212.
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Calvin, James M., and Marvin K. Nakayama. "Permuted derivative and importance-sampling estimators for regenerative simulations." European Journal of Operational Research 156, no. 2 (July 2004): 390–414. http://dx.doi.org/10.1016/s0377-2217(03)00070-5.
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Boikov, Konstantin A. "Regenerative system in passive radiosensory technical diagnostics of electronic devices." T-Comm 16, no. 2 (2022): 16–21. http://dx.doi.org/10.36724/2072-8735-2022-16-2-16-21.
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This work is devoted to the problem of processing signal radio profiles with a duration of less than 1 ns. These radio profiles are obtained by registering the electrical component of the near field of electromagnetic radiation induced by the electronic unit of the device using the method of passive radio engineering diagnostics. The reasons for the occurrence of significant errors in the processing of signal radio profiles by modern methods of direct analog-to-digital conversion and parallel conversion of real time are shown, associated with a decrease in the number of effective bits, an increase in sampling irregularity and signal rise time. A method is proposed for reducing the arising errors by switching to the method of stroboscopic scale-to-time transformation using multiple repro duction (regeneration) of a complex signal section by means of the previously presented regenerative system. Numerical modeling of the functioning of the regeneration system together with a stroboscopic time-scale converter was carried out in the study of the area of interest in the signal radio profile in the Simulink environment of the MatLab package. Using the correlation analysis of the reconstructed and the original signal radio profile, the validity of the use of the regenerative system in the processing and recovery of signal radio profiles of subnanosecond duration is shown. An experiment was prepared and carried out using modern high-speed equipment: a real-time oscilloscope and a stroboscopic oscilloscope with a subpicosecond sampling to study the correctness of the applicability of the regeneration method when combining the scale-time transformation and real-time transformation. The result of the stroboscopic scale-to-time transformation in the equivalent time mode with the transfer of the section to the general signal reconstructed in real time is presented. It is concluded that the accuracy of processing the original signal is increased by means of regeneration followed by restoration by methods of stroboscopic scale-time transformation, which allows further analysis of the signal radio profile with the smallest errors. Also, the regeneration system together with the strobe-frame-sampler can be used as a hardware method for conducting passive radiosensor technical diagnostics.
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Bhattacharya, Sourabh. "Consistent estimation of the accuracy of importance sampling using regenerative simulation." Statistics & Probability Letters 78, no. 15 (October 2008): 2522–27. http://dx.doi.org/10.1016/j.spl.2008.02.030.
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Stefanou, A., and G. Gielen. "Mitigation of sampling distortion in regenerative comparators by passive source degeneration." Electronics Letters 47, no. 11 (2011): 645. http://dx.doi.org/10.1049/el.2011.0906.
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Ghaleb, Hatem, Paolo Valerio Testa, Stefan Schumann, Corrado Carta, and Frank Ellinger. "A 160-GHz Switched Injection-Locked Oscillator for Phase and Amplitude Regenerative Sampling." IEEE Microwave and Wireless Components Letters 27, no. 9 (September 2017): 821–23. http://dx.doi.org/10.1109/lmwc.2017.2734741.
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Lu, Z. G., P. Campbell, and X. C. Zhang. "Free-space electro-optic sampling with a high-repetition-rate regenerative amplified laser." Applied Physics Letters 71, no. 5 (August 4, 1997): 593–95. http://dx.doi.org/10.1063/1.119803.
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Carlowitz, Christian, Thomas Girg, Hatem Ghaleb, and Xuan-Quang Du. "Efficient Ultra-High Speed Communication with Simultaneous Phase and Amplitude Regenerative Sampling (SPARS)." Frequenz 71, no. 9-10 (September 26, 2017): 449–61. http://dx.doi.org/10.1515/freq-2017-0163.
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Abstract For ultra-high speed communication systems at high center frequencies above 100 GHz, we propose a disruptive change in system architecture to address major issues regarding amplifier chains with a large number of amplifier stages. They cause a high noise figure and high power consumption when operating close to the frequency limits of the underlying semiconductor technologies. Instead of scaling a classic homodyne transceiver system, we employ repeated amplification in single-stage amplifiers through positive feedback as well as synthesizer-free self-mixing demodulation at the receiver to simplify the system architecture notably. Since the amplitude and phase information for the emerging oscillation is defined by the input signal and the oscillator is only turned on for a very short time, it can be left unstabilized and thus come without a PLL. As soon as gain is no longer the most prominent issue, relaxed requirements for all the other major components allow reconsidering their implementation concepts to achieve further improvements compared to classic systems. This paper provides the first comprehensive overview of all major design aspects that need to be addressed upon realizing a SPARS-based transceiver. At system level, we show how to achieve high data rates and a noise performance comparable to classic systems, backed by scaled demonstrator experiments. Regarding the transmitter, design considerations for efficient quadrature modulation are discussed. For the frontend components that replace PA and LNA amplifier chains, implementation techniques for regenerative sampling circuits based on super-regenerative oscillators are presented. Finally, an analog-to-digital converter with outstanding performance and complete interfaces both to the analog baseband as well as to the digital side completes the set of building blocks for efficient ultra-high speed communication.
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Xu, Zhao-bin, Xiao-jun Jin, Chao-jie Zhang, and Zhong-he Jin. "Analyses of noncommensurate sampling used in high-precision regenerative pseudo-noise ranging systems." Journal of Central South University 21, no. 3 (March 2014): 963–69. http://dx.doi.org/10.1007/s11771-014-2025-1.
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Sevchenko, S., M. Rublenko, and O. Bonkovsky. "Technologies for producing platelet masses for regenerative medicine." Naukovij vìsnik veterinarnoï medicini, no. 2(152) (December 17, 2019): 105–17. http://dx.doi.org/10.33245/2310-4902-2019-152-2-105-117.
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The development of regenerative medicine is to improve existing and to search for new tools for morphological and functional tissue repair, among which plasma or fi brin enriched with platelets (PRP and PRF) can be signifi cant. Autogenic platelet masses stimulate collagen synthesis, induce vascular growth, reduce pain, provide hemostasis, accelerate regeneration, reduce the risk of postoperative infectious and infl ammatory complications, and also have powerful osteoinductive properties. Due to the ability to produce the majority of growth factors, platelets can aff ect all stages of the infl ammatory-regenerative process, and therefore their biological products are of great importance in solving the problems of regenerative medicine. The technologies for obtaining PRP and PRF are based on centrifugation of blood, as a result of which its active components are concentrated in certain areas of the centrifuge. Blood sampling with or without an anticoagulant, as well as modifi cation of centrifugation protocols, allows to obtain various forms of platelet masses, such as a liquid, gel or clots. They are classifi ed, depending on the cellular content and architecture of fi brin, into several categories, namely: pure plasma enriched in platelets (P-PRP), plasma enriched in leukocytes and platelets (L-PRP); injectable fi brin enriched with platelets (i-PRF) and pure fi brin enriched with platelets (P-PRF), as well as fi brin enriched with white blood cells and platelets (L-PRF). The main diff erence in the manufacture of PRP compared to PRF is the use of anticoagulants and activators, as well as the possibility of using two-stage centrifugation. Platelet mass is used as an independent component mainly to stimulate the restoration of muscle tissue, to heal chronic wounds, to treat articular pathologies, and in combination with other materials, in particular to replace bone defects. The mechanisms of infl uence of each of the categories of platelet mass on tissue regeneration remains poorly understood. It is necessary to standardize the protocols for their preparation, taking into account the infl uence of additional substances, such as platelet activators or blood clotting and anticoagulants, as well as optimization of the methods for using each of the platelet mass forms. Key words: platelets, PRP, PRF, centrifuges, centrifugal force.
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Jin, Xiaojun, Wei Zhang, Shiming Mo, Zhaobin Xu, Chaojie Zhang, and Zhonghe Jin. "Optimal regenerative PN code tracking based on non‐commensurate sampling and double‐loop structure." Electronics Letters 55, no. 23 (November 2019): 1254–55. http://dx.doi.org/10.1049/el.2019.2397.
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Svolacchia, Fabiano, and Lorenzo Svolacchia. "Use of microfiltered vs only disaggregated mesenchymal stem cells from adipose tissue in regenerative medicine." Scripta Medica 51, no. 3 (2020): 152–57. http://dx.doi.org/10.5937/scriptamed51-24968.
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Background: Clinical use of adult mesenchymal stem cells (MSCa) in medicine and regenerative surgery is constantly evolving. Adipose tissue-derived stem cells (ADSc) are capable of inducing the production of new extracellular matrix (ECM), deposition of new collagen and early revascularisation. Methods: Flow cytometry was performed for 2 mL of cell colonies harvested from adipose tissue (AT). Comparation has been made of at disaggregated only and the same at disaggregated and microfiltered at 50 mm, 100 mm and 200 mm. Signs of inflammation after dermo-epidermal regeneration session through the mesotherapy method were observed and compared. Results: Even after filtration, significant number of ADSc was collected. An increase in the size of the filter did not always translate into an increase in the number of cells that were found in the microfiltrate. In the non-filtered at disaggregated in both cases, highest number of cells was found, as expected, but at the expense of more pronounced inflammation. Sampling with the 16 Gauge needle produces superior results compared to the cannula in all cases. Conclusion: With this method in medicine and regenerative surgery it will be easier to exploit the growth factors, mRNA, MicroRNA, lipids and bioactive peptides emitted in the MSCa signalling micro-vesicles as they are isolated from the inflammatory component.
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Graiet, Hajer, Anna Lokchine, Pauline Francois, Melanie Velier, Fanny Grimaud, Maxime Loyens, Yael Berda-Haddad, et al. "Use of platelet-rich plasma in regenerative medicine: technical tools for correct quality control." BMJ Open Sport & Exercise Medicine 4, no. 1 (November 13, 2018): e000442. http://dx.doi.org/10.1136/bmjsem-2018-000442.
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Background/aimsPlatelet-rich plasma (PRP) injections are used in sports medicine and have been the subject of increased clinical interest. However, there have been very few reports of the composition of initial whole blood and the final PRP product. The objective of this study was to provide technical tools to perform a correct characterisation of platelets, leucocytes and red blood cells (RBCs) from whole blood and PRP.MethodsBlood and PRP were obtained from 26 healthy volunteers and prepared according to the varying parameters encountered within PRP process preparation and quantification (harvesting method, anticoagulant used, sampling method, counting method). Concentrations were measured at t=0, t=1, t=6 and t=24 hours.ResultsSampling of blood in Eppendorf tubes significantly decreased platelet concentration over time, whereas sampling in Microvette EDTA-coated tube kept platelet concentration stable until 24 hours. A non-significant difference was observed in platelet counts in PRP with impedance (median (IQR): 521.8 G/L (505.3–524.7)) and fluorescence (591.5 G/L (581.5–595.8)) methods. Other studied parameters did not influence platelet concentrations in blood or PRP samples. Leucocytes and RBC counts were similar whatever the anticoagulant, sampling, harvesting and counting methods used for both blood and PRP samples.ConclusionsSystematic sampling of blood and PRP in EDTA-coated tubes for quality control is recommended. The use of a validated counter for PRP sample should also be taken into account.
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Spence, Stephanie, Takaaki Harada, Athanasios Margiolakis, Skylar Deckoff-Jones, Aaron N. Shugar, James F. Hamm, Keshav M. Dani, and Anya R. Dani. "Applicability of Femtosecond Lasers in the Cross-section Sampling of Works of Art." MRS Advances 2, no. 33-34 (2017): 1801–4. http://dx.doi.org/10.1557/adv.2017.242.
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ABSTRACTIssues in traditional cross-section sampling of paintings and other cultural artifacts with a scalpel, such as crumbling, delamination and paint compression, can deter conservators from sampling fragile paint layers. Often, such sampling carries the risk of causing further damage from a scalpel, which outweighs the benefits of scientific investigation. Here, we show that femtosecond lasers offer a viable alternative to obtaining cross-sections with minimal damage to the surrounding artwork. A Regenerative Ti:Sapphire amplifier system with a pulse duration of 70 femtoseconds, a few milliwatts of average power and a repetition rate of 1 kHz (1000 pulses/sec) was used for the study. Tests were performed on oil paintings ranging in age from the 19th century to late 20th century. Effective settings were determined to be 2 mW of power at a speed of 10mm/sec using an 800nm laser. Preliminary results suggest femtosecond lasers could be a viable alternative for obtaining paint cross-sections when traditional sampling methods cause unnecessary damage to fragile materials.
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Virda, Maryam, Muhammad Bader Munir, Nighat Shafi, Haroon Asghar Ginai, Mamoona Ali, and Mahrukh Anwar. "Regenerative Endodontics Procedure in Treatment of Permanent Immature Teeth with Necrotic Pulp." Pakistan Journal of Medical and Health Sciences 15, no. 8 (August 25, 2021): 1899–902. http://dx.doi.org/10.53350/pjmhs211581899.
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Aim: To evaluate the radiographical success of Regenerative endodontics procedure in permanent immature teeth with necrotic pulp. Methods: This Descriptive case series was conducted at the Department of Operative Dentistry, de’Montmorency College of Dentistry/ Punjab Dental Hospital, Lahore from November 2015 to November 2016. A total of 30 cases were included using non-probability consecutive sampling. Patients of both genders with age range from 9 to 14 years were considered. Performance of procedure and evaluation of success was done in terms of root development on periapical radiographs. . Data was entered and analysed with IBM SPSS 20. Level of significance was kept at p-value ≤ 0.05 Results: Out of 30 patients, 13 were females and 17 were males. Mean age of patients included in this study was 11.5±1.737. Follow up at 12 months showed 90% success, with 27 cases showed root development on periapical radiograph. There was no significant relation of success with age and gender of patient with p- value greater than 0.05. Conclusion: It is concluded from current study that Regenerative Endodontics procedure in permanent immature teeth is encouraging and can be recommended for the treatment of permanent immature teeth with necrotic pulp. Further research studies are required for evaluation of root development in regenerative endodontics procedure. Key words: Regenerative Endodontics, Permanent Immature teeth, Root development
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Iafrati, Steve. "The investment and regenerative value of addiction treatment." Drugs and Alcohol Today 15, no. 1 (March 2, 2015): 12–20. http://dx.doi.org/10.1108/dat-10-2014-0037.
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Purpose – The purpose of this paper is to show that despite welfare retrenchment and political rhetoric towards welfare, spending on residential addiction treatment should be protected. Design/methodology/approach – Examining benefits in context of costs, the research used social return on investment to monetise benefits and compare with costs. Based at a residential addiction centre, the research used questionnaires and focus groups with residents and former residents. Findings – The centre created almost £4 of benefit for every £1 of cost. Whilst the bulk of savings came from health, housing and criminal justice, there was also a regenerative impact for the local economy. Research limitations/implications – Sampling in sensitive themes is always problematic, however, the research had contact with many respondents, achieved data saturation and used the centre's success rate as a guide to weight the findings. Practical implications – The benefits of addiction treatment go beyond health outcomes and raise questions about how this should be reflected in cost distribution. Consequently, this has implications for the ways in which addiction services should be measuring their successes beyond solely health outcomes. Social implications – Existing research has largely overlooked the benefit of addiction treatment to the local economy and the fact that, as an investment, this benefit will continue to grow as more people enter the labour market over time. Originality/value – The research recognises the political context of funding and measures success beyond solely health outcomes. Furthermore, the research recognises the regenerative impact of addiction treatment, which is often overlooked in similar research.
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Gissi, Davide B., Achille Tarsitano, Andrea Gabusi, Roberto Rossi, Giuseppe Attardo, Jacopo Lenzi, Claudio Marchetti, Lucio Montebugnoli, Maria P. Foschini, and Luca Morandi. "13-gene DNA Methylation Analysis from Oral Brushing: A Promising Non Invasive Tool in the Follow-up of Oral Cancer Patients." Journal of Clinical Medicine 8, no. 12 (December 2, 2019): 2107. http://dx.doi.org/10.3390/jcm8122107.
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Background: This study aimed to evaluate the prognostic value of a non-invasive sampling procedure based on 13-gene DNA methylation analysis in the follow-up of patients previously treated for oral squamous cell carcinoma (OSCC). Methods: The study population included 49 consecutive patients treated for OSCC. Oral brushing sample collection was performed at two different times: before any cancer treatment in the tumor mass and during patient follow-up almost 6 months after OSCC treatment, within the regenerative area after OSCC resection. Each sample was considered positive or negative in relation to a predefined cut-off value. Results: Before any cancer treatment, 47/49 specimens exceeded the score and were considered as positive. Six months after OSCC resection, 16/49 specimens also had positive scores in the samples collected from the regenerative area. During the follow-up period, 7/49 patients developed locoregional relapse: 6/7 patients had a positive score in the regenerative area after OSCC resection. The presence of a positive score after oral cancer treatment was the most powerful variable related to the appearance of locoregional relapse. Conclusion: 13-gene DNA methylation analysis by oral brushing may have a clinical application as a prognostic non-invasive tool in the follow-up of patients surgically treated for OSCC.
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NADEAU, L. B., and W. H. VANDEN BORN. "THE ROOT SYSTEM OF CANADA THISTLE." Canadian Journal of Plant Science 69, no. 4 (October 1, 1989): 1199–206. http://dx.doi.org/10.4141/cjps89-142.
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The severity of infestations of Canada thistle (Cirsium arvense (L.) Scop.) can be predicted by determining the potential of its root system to expand and produce new shoots. The root systems of young and old plants of Canada thistle were observed under field conditions found in Alberta. Eighteen-week-old plants grown in 1985 and 1986 had an average of 26 aboveground shoots, 154 underground shoots, and 111 m of roots with a diameter larger than 0.5 mm. The number of root buds and the regenerative capacity of the roots varied between years. Four times as many nonemerged root buds per meter of root were present on plants grown in 1986 compared to 1985, and 50% more shoots per meter were produced from 10-cm-long root fragments collected from 18-wk-old plants in 1986 than in 1985. On average, an 18-wk-old plant had the potential of producing 930 shoots if its root system was cut into 10-cm-long pieces. The depth reached by roots in a 10-yr-old stand was about 2 m, with the major part of the root system being below the top 20 cm of soil. There was no correlation between the number of root buds present at sampling time and the number of shoots produced from root fragments planted in pots in the greenhouse. An average of eight shoots per meter of root was produced, irrespective of sampling depth.Key words: Canada thistle, Cirsium arvense, root buds, root system, regenerative capacity
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Lu, Bing, Hong Wen He, and Qun Ce Wang. "Control Strategy and Deterministic Optimization Research for Parallel Compound Braking System." Applied Mechanics and Materials 789-790 (September 2015): 878–82. http://dx.doi.org/10.4028/www.scientific.net/amm.789-790.878.
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Through the design way of reducing dimension, a control algorithm of the parallel compound braking is put forwarded. The flow of reducing dimension is designed, the sampling which is based on the Design of Experiment (DOE) and off-line deterministic optimization are accomplished. The reducing dimension of dual-motor coordinate coefficient is designed and the prediction model of parallel compound braking is constructed, which are based on the data of deterministic optimization. The analysis of reliability shows that the algorithm has a higher reliability and the energy recovery efficiency of the vehicle regenerative braking is improved under the condition of well braking stability.
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Eni, D. D., A. I. Iwara, and R. A. Offiong. "Analysis of Soil-Vegetation Interrelationships in a South-Southern Secondary Forest of Nigeria." International Journal of Forestry Research 2012 (2012): 1–8. http://dx.doi.org/10.1155/2012/469326.
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Soil-vegetation interrelationships in a secondary forest of South-Southern Nigeria were studied using principal component analysis (PCA) and canonical correlation analysis (CCA). The grid system of vegetation sampling was employed to randomly collect vegetation and soil data from fifteen quadrats of 10 m × 10 m. PCA result showed that exchangeable sodium, organic matter, cation exchange capacity, exchangeable calcium, and sand content were the major soil properties sustaining the regenerative capacity and luxuriant characteristics of the secondary forest, while tree size and tree density constituted the main vegetation parameters protecting and enriching the soil for its continuous support to the vegetation after decades of anthropogenic disturbance (food crop cultivation and illegal logging activities) before its acquisition and subsequent preservation by the Cross River State government in 2003. In addition, canonical correlation analysis showed result similar to PCA, as it indicated a pattern of relationship between soil and vegetation. The only retained canonical variate revealed a positive interrelationship between organic matter and tree size as well as an inverse relationship between organic matter and tree density. These extracted soil and vegetation variables are indeed significantly important in explaining soil-vegetation interrelationships in the highly regenerative secondary forest.
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Simmonds, J. A., and S. D. Nelson. "Improved Micropropagation of Begonia × hiemalis by Maintaining Donor Plants in Long-day Conditions." HortScience 24, no. 5 (October 1989): 831–32. http://dx.doi.org/10.21273/hortsci.24.5.831.
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Abstract The effect of donor plant photoperiod on subsequent in vitro adventitious bud production of Begonia × hiemalis (Fotsch) cv. Schwabenland Pink was monitored by sampling petiole explants from plants maintained in either short- (8 hr, SD) or long-day (16 hr, LD) photoperiods. Adventitious bud production on SD and LD explants was similar for the first 28 days of treatment. A subsequent loss of regenerative capacity occurred in SD explants and was associated with the changing physiological status of the donor plant. Maintaining donor plants in LD increased bud production and extended the time during which the donor plants could be used effectively in commercial micropropagation programs.
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Alanís-Rodríguez, E., E. A. Rubio-Camacho, J. M. Mata-Balderas, E. A. Lozano-Cavazos, M. A. González-Tagle, and M. F. Amarán-Ruiz. "Tamaulipan thornscrub after fire: an analysis of the composition of species." Brazilian Journal of Biology 80, no. 4 (December 2020): 814–22. http://dx.doi.org/10.1590/1519-6984.221325.
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Abstract Forest fires are a natural element in many terrestrial ecosystems, in Mexico one of the main causes of loss of vegetation coverage is related to them. Nevertheless, no research has been carried out in the Tamaulipan thornscrub communities regarding post-fire regenerative strategies of plant species, therefore, is important to generate knowledge about the ecological role of fire in them. The aim of this study is to characterize the arboreal and shrub vegetation of a Tamaulipan thornscrub community in the Northeast of Mexico after a fire. To determine the composition, diversity and structure of the floral community consisting of trees and shrubs, 6 square-shaped sampling sites of 1,600 m2 were established 3 years after the fire. Margalef (DMg), Shannon-Weiner (H’) and Pretzsch (A) indices were calculated to determine the richness, diversity and vertical stratification of species, respectively.23 species, 21 genera and 14 families of vascular plants were registered. The most species were Fabaceae (6) and Rhamnaceae (3) and Cordia boissieri was the specie with greater ecological weight (IVI = 20.3%). The indexes of richness and true diversity (DMg = 3.16; D = 16.44) showed high values, which suggests that the post-fire area has a good regeneration and a high species diversity. With these results we can conclude that the fire is an important agent of change in successional stages of Tamaulipan thornscrub with high values of regeneration after a surface fire.
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Mortensen, Kim Erlend, Lene Nagstrup Conley, Jakob Hedegaard, Trine Kalstad, Peter Sorensen, Christian Bendixen, and Arthur Revhaug. "Regenerative response in the pig liver remnant varies with the degree of resection and rise in portal pressure." American Journal of Physiology-Gastrointestinal and Liver Physiology 294, no. 3 (March 2008): G819—G830. http://dx.doi.org/10.1152/ajpgi.00179.2007.
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After parenchymal loss, the liver regenerates restoring normal mass and metabolic function. Prevailing theories on triggering events leading to regeneration include humoral, metabolic, and flow-mediated mechanisms, the latter emphasizing the importance of shear stress mediated nitric oxide regulation. We aimed to investigate whether the grade of resection and hence the portal venous pressure and sinusoidal shear stress increase would be reflected in the gene expression profiles in the liver remnant by using a global porcine cDNA microarray chip with ∼23,000 genes represented. Six pig livers were resected with 62% (low portal pressure resection) and 75% (high portal pressure resection), resulting in a portal venous pressure increase from a baseline of 6.1–8.2 and 12 mmHg, respectively. By sampling consecutive biopsies from the liver remnants, we found differentially expressed genes in the high portal pressure resection group to have functions related primarily to apoptosis, nitric oxide metabolism and oxidative stress, whereas differentially expressed genes in the low portal pressure resection group potentially regulate the cell cycle. Common to both groups was the upregulation of genes regulating inflammation, transport, cell proliferation, development, and protein metabolism. Also common to both groups was both up- and downregulation of genes regulating cell-cell signaling, signal transduction, cell adhesion, and translation. Genes regulating the metabolism of lipids, hormones, amines, and alcohol were downregulated in both groups. In conclusion, the genetic regenerative response in the liver remnant to varies according to the level of resection.
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Li, Hanluo, Federica Francesca Masieri, Marie Schneider, Tina Kottek, Sebastian Hahnel, Kensuke Yamauchi, Danilo Obradović, et al. "Autologous, Non-Invasively Available Mesenchymal Stem Cells from the Outer Root Sheath of Hair Follicle Are Obtainable by Migration from Plucked Hair Follicles and Expandable in Scalable Amounts." Cells 9, no. 9 (September 10, 2020): 2069. http://dx.doi.org/10.3390/cells9092069.
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Background: Regenerative therapies based on autologous mesenchymal stem cells (MSC) as well as stem cells in general are still facing an unmet need for non-invasive sampling, availability, and scalability. The only known adult source of autologous MSCs permanently available with no pain, discomfort, or infection risk is the outer root sheath of the hair follicle (ORS). Methods: This study presents a non-invasively-based method for isolating and expanding MSCs from the ORS (MSCORS) by means of cell migration and expansion in air–liquid culture. Results: The method yielded 5 million cells of pure MSCORS cultured in 35 days, thereby superseding prior art methods of culturing MSCs from hair follicles. MSCORS features corresponded to the International Society for Cell Therapy characterization panel for MSCs: adherence to plastic, proliferation, colony forming, expression of MSC-markers, and adipo-, osteo-, and chondro-differentiation capacity. Additionally, MSCORS displayed facilitated random-oriented migration and high proliferation, pronounced marker expression, extended endothelial and smooth muscle differentiation capacity, as well as a paracrine immunomodulatory effect on monocytes. MSCORS matched or even exceeded control adipose-derived MSCs in most of the assessed qualities. Conclusions: MSCORS qualify for a variety of autologous regenerative treatments of chronic disorders and prophylactic cryopreservation for purposes of acute treatments in personalized medicine.
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Dai, J. G., and Mark Gluzman. "Queueing Network Controls via Deep Reinforcement Learning." Stochastic Systems 12, no. 1 (March 2022): 30–67. http://dx.doi.org/10.1287/stsy.2021.0081.
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Novel advanced policy gradient (APG) methods, such as trust region policy optimization and proximal policy optimization (PPO), have become the dominant reinforcement learning algorithms because of their ease of implementation and good practical performance. A conventional setup for notoriously difficult queueing network control problems is a Markov decision problem (MDP) that has three features: infinite state space, unbounded costs, and long-run average cost objective. We extend the theoretical framework of these APG methods for such MDP problems. The resulting PPO algorithm is tested on a parallel-server system and large-size multiclass queueing networks. The algorithm consistently generates control policies that outperform state-of-art heuristics in literature in a variety of load conditions from light to heavy traffic. These policies are demonstrated to be near optimal when the optimal policy can be computed. A key to the successes of our PPO algorithm is the use of three variance reduction techniques in estimating the relative value function via sampling. First, we use a discounted relative value function as an approximation of the relative value function. Second, we propose regenerative simulation to estimate the discounted relative value function. Finally, we incorporate the approximating martingale-process method into the regenerative estimator.
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MCDONALD, DAVID, CHU CHENG, YUANYUAN CHEN, and DOUGLAS ZOCHODNE. "Early events of peripheral nerve regeneration." Neuron Glia Biology 2, no. 2 (December 1, 2005): 139–47. http://dx.doi.org/10.1017/s1740925x05000347.
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Early regeneration of injured peripheral nerves involves a series of events that are important in the success of eventual reconnection. In many nerve injuries, such as transections with gaps, axons and Schwann cells (SCs) penetrate into new microenvironments de novo, not involving zones of Wallerian degeneration. We studied unexplored axon–SC interactions by sampling of newly forming connections through a silicone conduit across transected rat sciatic peripheral nerve gaps. Axon and SC participation in bridge formation was addressed by light microscopy, electron microscopy and by double-labeling immunohistochemistry, including confocal imaging, and several, less appreciated aspects of early regrowth were identified. There are limitations to early and widespread regeneration of axons and SCs into bridges initially formed from connective tissue and blood vessels. Regrowth is ‘staggered’ such that only a small percentage of parent axons sampled the early bridge. There is an intimate, almost invariable relationship between SCs and extension of axons, which challenges the concept that axons lead and SCs follow. ‘Naked’ axons were infrequent and limited in scope. Axons did not seek out and adhere to vascular laminin but intimately followed laminin deposits associated with apposed SCs. Growth cones identified by labeling of β III tubulin, PGP 9.5 and GAP43/B50 were complex, implying a pause in their regrowth, and were most prominent at the proximal stump–regenerative bridge interface. There is surprising and substantial hostility to local regrowth of axons into newly forming peripheral nerve bridges. Early axon outgrowth, associated with apposed Schwann cell processes, is highly constrained even when not exposed to adjacent myelin and products of Wallerian degeneration.
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Ott, Jacqueline P., Jitka Klimešová, and David C. Hartnett. "The ecology and significance of below-ground bud banks in plants." Annals of Botany 123, no. 7 (May 31, 2019): 1099–118. http://dx.doi.org/10.1093/aob/mcz051.
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AbstractBackgroundBelow-ground bud banks have experienced much recent interest due to discoveries that they (1) account for the majority of seasonal population renewal in many communities, (2) are crucial to regeneration following disturbance, and (3) have important consequences for plant population dynamics and plant and ecosystem function across a number of habitats.ScopeThis review presents an overview of the role of bud banks in plant population renewal, examines bud bank life history, summarizes bud bank traits and their potential ecological implications, synthesizes the response of bud banks to disturbance, and highlights gaps to guide future research. The characteristics and life history of buds, including their natality, dormancy, protection and longevity, provide a useful framework for advancing our understanding of bud banks. The fate of buds depends on their age, size, type, location, and biotic and abiotic factors that collectively regulate bud bank dynamics. A bud bank can provide a demographic storage effect stabilizing population dynamics, and also confer resistance to disturbance and invasion. Regeneration capacity following disturbance is determined by interactions among the rates of bud natality, depletion and dormancy (meristem limitation), and the resources available to support the regeneration process. The resulting response of plants and their bud banks to disturbances such as fire, herbivory and anthropogenic sources determines the community’s regenerative capacity.ConclusionsVegetation responses to environmental change may be mediated through changes in bud bank dynamics and phenology. Environmental change that depletes the bud bank or prohibits its formation likely results in a loss of vegetation resilience and plant species diversity. Standardization of bud sampling, examination of bud banks in more ecosystems and their response to environmental variation and disturbance regimes, employment of stage-structured bud bank modelling and evaluation of the cost of bud bank construction and maintenance will benefit this expanding field of research.
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Slamet, Agus, Bayu Kanetro, and Agus Setiyoko. "The hypoglycemic and regenerative effect of the pancreas using instant porridge mix of pumpkin and brown rice flour on diabetic rats." Potravinarstvo Slovak Journal of Food Sciences 16 (March 10, 2022): 92–100. http://dx.doi.org/10.5219/1705.
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Diabetes is a congenital disease resulting from inefficiencies in insulin production and activities. Instant porridge mixed with pumpkin and brown rice (instant porridge mix) can be a functional food to lower blood sugar. This study aimed to determine the hypoglycemic activity and the ability of instant porridge mix to regenerate pancreatic beta cells in diabetic rats. Diabetes was induced by Streptozotocin (STZ). Instant porridge mix was used to substitute the standard feed AIN-93 at 0, 10, 20, and 30% levels. The hypoglycemic activity test used 30 Sprague Dawley rats assigned to five groups with six each. The groups were (1) normal rats fed with standard feed AIN-93, (2) DM/diabetes mellitus rats fed with AIN 93 feed, (3) DM rats fed with 10% instant porridge mix, (4) DM rats fed with 20% instant porridge mix, and (5) DM rats fed with 30% instant porridge mix. The treatment was carried out for twenty-eight days, and blood sampling was carried out at seven-day intervals for blood analysis to determine glucose levels. At the end of the study, the levels of MDA (malondialdehyde) and blood glucose in the liver of the rats were also analyzed. A histopathology test was also done on the pancreas. The results showed that feed substitution (20%) with instant porridge mix significantly (p <0.05) reduced the level of blood glucose from 271.81 to 99.66 mg.dL-1 in DM rats. In conclusion, DM rats fed with 20% instant porridge mix were the best treatment for hypoglycemic and regenerative effects of the pancreas.
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Koidou, V. P., G. S. Chatzopoulos, I. Tomas, L. Nibali, and N. Donos. "Expression of gingival crevicular fluid markers during early and late healing of intrabony defects after surgical treatment: a systematic review." Clinical Oral Investigations 24, no. 1 (November 7, 2019): 487–502. http://dx.doi.org/10.1007/s00784-019-03088-4.
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Abstract Background Surgical treatments such as guided tissue regeneration (GTR) and access flap surgery are widely employed for the treatment of intrabony defects. However, little is known regarding the postoperative expression of gingival crevicular fluid (GCF) markers. Objective The aim of this systematic review was to compare the expression of GCF markers following treatment of periodontal intrabony defects with guided tissue regeneration or access surgery. The association of the markers’ expression with the clinical outcome was also assessed. Methods An electronic literature search was conducted in MEDLINE, EMBASE, OpenGrey, LILACS and Cochrane Library up to December 2018 complemented by a manual search. Human, prospective clinical studies were identified. The changes from baseline up to 30 days (early healing) and 3 months (late healing) were assessed. Results A total of 164 publications were identified and reviewed for eligibility. Of these, 10 publications fulfilled the inclusion criteria. The included studies evaluated 15 different GCF markers with a follow-up time between 21 and 360 days postoperatively. PDGF, VEGF and TIMP-1 changes were often investigated in the included studies; however, contrasting results were reported. Two studies agreed that both GTR and OFD lead to similar OPG level changes. TGF-β1 is increased early postoperatively, irrespective of the surgical technique employed. Conclusion There is limited evidence available on the expression of GCF markers after surgical interventions of intrabony periodontal defects. However, OPG and TGF-β1 tend to increase early post-operatively, irrespective of the surgical technique employed, irrespective of the surgical technique employed. Clinical relevance More well-designed, powered studies with sampling periods reflecting the regenerative process are needed, and future research should focus on employing standardised protocols for collecting, storing and analysing GCF markers.
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Grigoryeva, YuV V., GN N. Suvorova, NA A. Renz, and AV V. Bormotov. "COMPARATIVE ASPECTS OF REGENERATIVE POTENCY OF SPHINCTER CERVICAL TISSUES IN RATS WITH CANALIS CERVICIS UTERI TRACTION UNDER EXPERIMENTAL CONDITIONS." Science and Innovations in Medicine 1, no. 1 (March 15, 2016): 31–35. http://dx.doi.org/10.35693/2500-1388-2016-0-1-31-35.
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Aim - to study the reparative regeneration processes after experimental gradual traction of cervix uteri in rats. Materials and methods. The object of the study is the cervix at the sphincter. We performed gradual traction of cervix uteri in 25 rats under aether anesthesia and gathered the samples.We analyzed the course of reparative regeneration and performed sampling after 1, 3, 5, 7, 10, 15, 21 and 30 days. We carried out complex morphological examination with optical and transmission electron microscopy, and immunohistochemistry. The immunohistochemical examination of cervical tissues was performed using a set of monoclonal antibodies to а-smooth muscle actin. Results. It was determined that cervical traction formed three distinguishable zones: the zone of damage, the periwound zone and the zone of morphological integrity. The zone of damage corresponds to the actual sphincter and the periwound zone - to pre- and postsphincteral compartments. Several myocytes undergo necrosis in the damage zone. There is no necrosis in the periwound area, but we found some abnormality of intercellular contacts due to the change of the morphology of intercellular substance. The experimental traction causes the development of local septic inflammation, affecting all the layers. The synthesis of fibrous connective tissue components starts in the proliferative phase. It leads to restructuring of histoarchitecture and disruption of the functional syncytium structure. Conclusion. Post-traumatic regeneration is performed by changing the phenotype of survived myocytes from mantle to mantle-synthetic myocytes with synthesis of the fiber component of the intercellular substance. Also, there is an incomplete mitosis in several myocytes, which leads to the formation of binuclear or polyploid cells.
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Maughan, J. R., K. M. Elward, S. M. De Pietro, and P. J. Bautista. "Field Test Results of a Dry Low NOx Combustion System for the MS3002J Regenerative Cycle Gas Turbine." Journal of Engineering for Gas Turbines and Power 119, no. 1 (January 1, 1997): 50–57. http://dx.doi.org/10.1115/1.2815561.
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A dry low NOx combustion system for the MS3002J regenerative cycle gas turbine has been developed and successfully installed at two pipeline compressor stations. Preparation for the DLN retrofits began with initial field testing of the conventional system intended to characterize some of the unique features of the two-shaft, regenerative cycle machine that might affect the proposed premixed combustor design. Combustor transition pieces were instrumented with gas sampling probes for CO2 analysis. Fuel flow to each combustor was measured and controlled. Consequently, the fuel/air ratio, exit temperature, and air flow for each combustor could be determined over the operating range. The dry low NOx combustion system for the MS3002J R/C is based on an existing system for the MS6001B gas turbine. A description of the hardware and system operation is given, Because of the relatively high inlet temperature of the MS3002J R/C (950°F), some portions of the liner required highly efficient effusion cooling. A new transition piece seal was developed to reduce leakage and ensure uniform air flow throughout the machine. A control strategy was developed to guide the machine through diffusion modes of operation at low load to premixed combustion at higher loads. Results showed acceptable component temperatures throughout. Emissions measurements were consistent with previous laboratory measurements and met design targets of 33 ppm NOx and 25ppm CO (at 15 percent O2) over the required range. The fuel split between the two premixed flame zones was controlled over the load range of the turbine to optimize CO, NOx, and liner temperatures. Because of the high inlet temperature and low overall temperature rise, dynamic pressure activity was low. Following a successful inspection after 6000 hours of operation, the hardware inspection interval has been set at 12,000 h.
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Sari, Desi Sandra, Ernie Maduratna, Fourier Dzar Eljabbar Latief, Alexander Patera Nugraha, Ketut Sudiana, and Fedik Abdul Rantam. "Osteogenic Differentiation and Biocompatibility of Bovine Teeth Scaffold with Rat Adipose-derived Mesenchymal Stem Cells." European Journal of Dentistry 13, no. 02 (May 2019): 206–12. http://dx.doi.org/10.1055/s-0039-1694305.
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Abstract Objective Adipose-derived mesenchymal stem cells (ADMSCs) have great potential for regenerative medicine. These have been combined with biomaterials such as Bovine teeth that are preferred as a periodontal regeneration material. The main purpose of this study is to evaluate and analyze a biocompatibility test and osteogenic differentiation of bovine teeth scaffold seeded with ADMSCs in vitro. Materials and Methods A true experimental study with post-test only group design was conducted. Random sampling and Lameshow's formula were used to determine the sample. The scaffold, obtained from bovine teeth as the bone graft material, was analyzed using 3- (4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and its attachment was evaluated by scanning electron microcopy (SEM) and micro-computed tomography with ADMSCs. ADMDSCs attachment present in the bovine teeth scaffold was assessed using SEM at 1-hour, 12-hour, and 24-hour intervals. Statistical Analysis Analysis of variance was used to analyze the MTT assay results (p < 0.05) based on normality and homogeneity test (p > 0.05). Results The highest viability of cells (97.08%) was found at a concentration of 10% by means of an MTT test (p < 0.05). The results of three-dimensional bovine teeth scaffold showed the average particle size to be 500 µm. ADMSCs cell attachment to the scaffold bovine teeth showed a significant increase in the number of cells attached after 24 hours compared with those at 1 and 12 hours. Alizarin red staining showed an increase in ADMSC osteogenic differentiation after it was combined with bovine teeth scaffold. Conclusion The scaffold from bovine teeth is biocompatible and accelerates osteogenic differentiation of ADMSC.
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Sasaki, Kazuya, Motonobu Endo, and Ikuko Inada. "Effects of Sampling Season of Explants and Growth Stage of Mother Plants on the Regenerative Capacity in Cultured Shoot Apices of Chrysanthemum (Dendranthema*grandiflorum (Ramat.) Kitam.)." Engei Gakkai zasshi 73, no. 1 (2004): 36–41. http://dx.doi.org/10.2503/jjshs.73.36.
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Gonsrang, S., and R. Kasper. "Optimisation-Based Power Management System for an Electric Vehicle with a Hybrid Energy Storage System." International Journal of Automotive and Mechanical Engineering 15, no. 4 (December 24, 2018): 5729–47. http://dx.doi.org/10.15282/ijame.15.4.2018.2.0439.
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Hybridisation of energy storage sources is necessary for extending mileage of electric vehicles. However, coordination of multiple devices with different characteristics is challenging. This paper presents a power management system (PMS) for an electric car equipped with a battery pack, supercapacitor bank, and range extender. The proposed PMS deals with vehicular load distribution by solving a power management problem, formulated as a constrained quadratic program (CQP). Then, the optimised variables, such as the desired speed and optimised operation points of the car’s components, are implemented by controllers at a component level. Complete knowledge about the trip is unwanted because the proposed PMS considers a power management problem only over a controlled horizon of one sampling period. Furthermore, this work varies weight factors to tackle various difficulties, for instance, regenerative power management. The simulation results revealed that the proposed system optimally allocated an electric power load to the car components, without violating any physical constraints. Also, the comparative study showed that the performance of the CQP in power management was comparable to that of the benchmark, based on a nonlinear model predictive control.
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Zhang, Ming, Kai Wang, and Yan-ting Zhou. "Online State of Charge Estimation of Lithium-Ion Cells Using Particle Filter-Based Hybrid Filtering Approach." Complexity 2020 (January 10, 2020): 1–10. http://dx.doi.org/10.1155/2020/8231243.
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Filtering based state of charge (SOC) estimation with an equivalent circuit model is commonly extended to Lithium-ion (Li-ion) batteries for electric vehicle (EV) or similar energy storage applications. During the last several decades, different implementations of online parameter identification such as Kalman filters have been presented in literature. However, if the system is a moving EV during rapid acceleration or regenerative braking or when using heating or air conditioning, most of the existing works suffer from poor prediction of state and state estimation error covariance, leading to the problem of accuracy degeneracy of the algorithm. On this account, this paper presents a particle filter-based hybrid filtering method particularly for SOC estimation of Li-ion cells in EVs. A sampling importance resampling particle filter is used in combination with a standard Kalman filter and an unscented Kalman filter as a proposal distribution for the particle filter to be made much faster and more accurate. Test results show that the error on the state estimate is less than 0.8% despite additive current measurement noise with 0.05 A deviation.
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Nuijten, Rik J. G., Nicholas C. Coops, Catherine Watson, and Dustin Theberge. "Monitoring the Structure of Regenerating Vegetation Using Drone-Based Digital Aerial Photogrammetry." Remote Sensing 13, no. 10 (May 16, 2021): 1942. http://dx.doi.org/10.3390/rs13101942.
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Measures of vegetation structure are often key within ecological restoration monitoring programs because a change in structure is rapidly identifiable, measurements are straightforward, and structure is often a good surrogate for species composition. This paper investigates the use of drone-based digital aerial photogrammetry (DAP) for the characterization of the structure of regenerating vegetation as well as the ability to inform restoration programs through spatial arrangement assessment. We used cluster analysis on five DAP-derived metrics to classify vegetation structure into seven classes across three sites of ongoing restoration since linear disturbances in 2005, 2009, and 2014 in temperate and boreal coniferous forests in Alberta, Canada. The spatial arrangement of structure classes was assessed using land cover maps, mean patch size, and measures of local spatial association. We observed DAP heights of short-stature vegetation were consistently underestimated, but strong correlations (rs > 0.75) with field height were found for juvenile trees, shrubs, and perennials. Metrics of height and canopy complexity allowed for the extraction of relatively tall and complex vegetation structures, whereas canopy cover and height variability metrics enabled the classification of the shortest vegetation structures. We found that the boreal site disturbed in 2009 had the highest cover of classes associated with complex vegetation structures. This included early regenerative (22%) and taller (13.2%) wood-like structures as well as structures representative of tall graminoid and perennial vegetation (15.3%), which also showed the highest patchiness. The developed tools provide large-scale maps of the structure, enabling the identification and assessment of vegetational patterns, which is challenging based on traditional field sampling that requires pre-defined location-based hypotheses. The approach can serve as a basis for the evaluation of specialized restoration objectives as well as objectives tailored towards processes of ecological succession, and support prioritization of future inspections and mitigation measures.
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Kong, Lingming, Xiaoli Zhu, and Liyi Zhang. "CORRELATION OF PSYCHOLOGICAL MALADJUSTMENT, SOCIAL SUPPORT AND PSYCHOSOMATIC HEALTH IN FRESHMAN AMONG COLLEGE STUDENTS." International Journal of Research -GRANTHAALAYAH 10, no. 8 (September 16, 2022): 156–63. http://dx.doi.org/10.29121/granthaalayah.v10.i8.2022.4760.
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To investigate the relationship between psychosomatic health and psychological maladjustment, social support in freshman. By random cluster sampling, 2790 freshmen garrisoned on islands (study group) and 2790 sophomore and junior college students as control group were recruited in Changzhou and administered by Chinese Psychosomatic Health Scale (CPHS), Maladjustment Self-Assessment Scale (MSAS) and Chinese Social Support Scale (CSSS). The results were analyzed with t test analysis, Pearson correlation and stepwise regression analysis by SPSS statistic 17.0. Compared with the controls, freshmen had higher scores of psychological disorder(anxiety depression, psychoticism) and of somatic disorder(respiratory apparatus, cardiovascular system, alimentary system, skeletal and musculature, integument, regenerative and endocrine, nervous system) except the factor of eye and ear; all factors of CPHS had positive correlation with most factors of MSAS, CSSS; regression analysis showed that behavioral problem, interpersonal relationship, environmental adaptation, subjective support, support degree of use entered into the regression equation. In conclusion, the psychosomatic health in freshman among college students is generally worse than those of the controls. Behavioral problem, interpersonal relationship, environmental adaptation, subjective support, support degree of use are associative factors predictive factors.
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Ekdal, Elçin, Arzu Ege, Turgay Karali, and Zafer Derin. "Luminescence dating studies of Yeşilova Hoyuk." Geochronometria 39, no. 4 (December 1, 2012): 268–75. http://dx.doi.org/10.2478/s13386-012-0013-5.
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Abstract Ceramic findings collected from Yeşilova Hoyuk located in Izmir were dated using the thermoluminescence dating technique. The area is of significant archaeological importance since it is the first prehistoric settlement in Izmir. Recent archeological observations suggest that human occupation of the region took place about 8500 years ago comparing to previously determined dates of 5000 years. Three samples collected from the same archaeological layer (Neolithic period) in Yeşilova Hoyuk were dated using the thermoluminescence method. Archaeological doses (AD) were obtained by single aliquot regenerative dose method (SAR) for thermoluminescence (TL) using coarse grain quartz minerals extracted from samples. Thick and thin Al2O3:C thermoluminescence dosimeters (TLD) were used to determine the annual dose rate. The archaeological doses were found to vary from 25.91±0.78 to 26.82±0.68 Gy, and the annual doses were found to be between 3.34±0.24 and 3.47±0.24 mGy/a. The ages obtained for the samples were determined to be 6000±830 BC, 5740±670 BC and 5460±740 years for samples ND1, ND2 and ND3, respectively, which supports the prediction of archeologist that the sampling layer dates from the Neolithic period.
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Przegiętka, Krzysztof, Paweł Molewski, Włodzimierz Juśkiewicz, Piotr Palczewski, and Marek Chabowski. "Characterisation and OSL dating of modern fluvial sediments in the lower Vistula River: testing the zeroing assumption." Bulletin of Geography. Physical Geography Series 10, no. 1 (June 1, 2016): 107–21. http://dx.doi.org/10.1515/bgeo-2016-0008.
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Abstract In this study modern sediments of the lower Vistula River were investigated to determine the relationship between the structure and texture (grain size, rounding and frosting) of the deposits and the possibility of their zeroing. The samples of modern fluvial deposits were collected from the lower Vistula River at two sites in Toruń and Ciechocinek. Sand bars newly emerged from the river were selected for testing. The coarse quartz grains were separated for OSL measurements. The single-aliquot regenerative (SAR) technique was applied for measuring equivalent doses from multigrain aliquots. The obtained dose estimates were found to be very low, proving the reliability of the OSL zeroing assumption. The dose rates were estimated by gamma-ray spectrometry, demonstrating homogeneity of the radiation field. Analysis did not show significant relationships between the examined sediments’ capacity to zeroing and their structural and textural characteristics, or the sampling site. The obtained OSL ages of the studied sediments date back hundreds of years and are probably overestimated. The results related to fossil sediments of bars of the age of thousands of years confirm their suitability for the OSL dating method.
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Sershen, Charmaine C. Drury, Clinton Carbutt, and Syd Ramdhani. "Seed banks of subtropical grassland patches within an urban matrix in South Africa: reflecting the past and foretelling the future." Botany 97, no. 4 (April 2019): 231–44. http://dx.doi.org/10.1139/cjb-2018-0155.
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Urban grasslands often exist as fragmented patches with varying threat levels. These patches are generally inappropriately managed due to limited data on their responses to disturbance and seed bank regenerative potential. This study compared seed banks between non-naturally disturbed and undisturbed patches of South African subtropical grasslands in an urban environment. Standing vegetation was characterised via year-round quadrat and monthly transect sampling. The seed banks were sampled after the two main dispersal periods and assessed for species composition and density. The seed bank species (24) represented a subset (9%) of the standing vegetation, with forbs being the most speciose life form and grasses the most abundant. Disturbance had a moderate impact on seed bank density but significantly affected species composition and ordering. Clustering and ordination analyses separated seed banks based on disturbance history. However, seed banks in disturbed patches maintained the general character of the grassland type. Diagnostic, rare and threatened taxa were absent from seed banks, irrespective of disturbance history. Consequently, restoration will possibly require seed enrichment and species reintroduction rather than exploitation of natural seed banks. Identifying disturbance-sensitive species through seed bank surveys can inform grassland conservation and restoration strategies.
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Laghezza, Francesco, Fabrizio Berizzi, Amerigo Capria, Andrea Cacciamano, Giovanni Serafino, Paolo Ghelfi, and Antonella Bogoni. "Reconfigurable radar transmitter based on photonic microwave signal generation." International Journal of Microwave and Wireless Technologies 3, no. 3 (March 25, 2011): 383–89. http://dx.doi.org/10.1017/s1759078711000262.
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In this paper we propose a photonic technique for a reconfigurable microwave signal generation based on the beating of two laser modes coming from a regenerative fiber mode-locked laser (FMLL) into a photodiode. The excellent performance of this kind of pulsed laser guarantees high stability on the directly generated microwave signal even at ultrahigh frequencies (up to W band). Therefore, by using the proposed architecture, the performance of a reconfigurable full digital coherent radar system can be enhanced for example in terms of moving target indicator (MTI) improvement factor and analog to digital converter maximum signal to noise ratio. Differently from the conventional radar oscillators, whose performance strongly deteriorate with increasing frequencies, the photonic radio frequency (RF) generation always shows an excellent spectral purity. Moreover, thanks to the achievable high repetition rates and the coherence properties of the FMLL, this laser scheme has also been proposed for digitizing, directly at RF, the received signal by electro-optical sampling. Thus the advantage of using just one device for signal generation in both the transmitter and receiver chain, makes the proposed solution a cost-effective architecture for microwave signal generation.
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Murray, Andrew, Ellen Wohl, and Jon East. "Thermoluminescence and Excess 226Ra Decay Dating of Late Quaternary Fluvial Sands, East Alligator River, Australia." Quaternary Research 37, no. 1 (January 1992): 29–41. http://dx.doi.org/10.1016/0033-5894(92)90004-3.
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AbstractThermoluminescence (TL) dating was applied to seven samples of siliceous fluvial sands from the East Alligator River of Northern Australia, giving ages ranging from modern to 6000 yr B.P. Two methods of estimating the equivalent dose (ED), total bleach and regenerative, were applied to the 90- to 125-μm quartz fraction of the samples in order to determine the reliability and internal consistency of the technique. High-resolution γ and α spectroscopy were used to measure radionuclide contents; these measurements revealed an excess 226Ra activity compared with 230Th. This excess decreased with depth, and was used directly to derive mean sedimentation rates, and thus sediment ages. Both this method and one 14C date confirmed the validity of the TL values, which increased systematically with depth and were consistent with site stratigraphy. TL was of limited use in the dating of these late Holocene deposits because of age uncertainties of 500 to 1600 yr, resulting from a significant residual ED. This residual probably resulted from incomplete bleaching during reworking upstream of the sampling site. For Pleistocene deposits, the residual ED will be less significant because of higher total EDs, and TL dates will be correspondingly more accurate.
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Bilodeau-Gauthier, Simon, Steve Bédard, and François Guillemette. "Assessing Post-Harvest Regeneration in Northern Hardwood and Mixedwood Stands: Evolution of Species Composition and Dominance within 15-Year-Old Group Selection and Patch Cutting." Forests 11, no. 7 (July 8, 2020): 742. http://dx.doi.org/10.3390/f11070742.
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Multi-cohort forest management in northern hardwood stands may well be the best way to successfully regenerate tree species of intermediate shade tolerance, such as yellow birch (Betula alleghaniensis Britt.). The creation of large enough gaps in the canopy favors increased light availability within the opening, while soil scarification provides suitable germination seedbeds. Evidence of these methods’ success nonetheless remains mostly the purview of experimental studies rather than operational tests. In Quebec, Canada, the multi-cohort methods promoted include group selection cutting and patch cutting. The present study tested their implementation at an operational scale and over a large territory in both hardwood-dominated and mixedwood stands. We assessed their efficacy in promoting natural regeneration of commercial hardwood trees, notably yellow birch and sugar maple (Acer saccharum Marsh.). We conducted regeneration surveys at 2, 5, 10, and 15 years after harvest. Overall, group selection and patch cuttings were successful in regenerating the target species. Yellow birch, for instance, showed a mean stocking around 60% and a mean sapling density around 3400 stems ha−1 after 15 years. We compared several variables for measuring regeneration in early years, and found that the relative abundance, the stocking based on one stem per sampling unit, and the mean maximum height were good predictors of the relative presence of yellow birch and sugar maple in 15-year-old canopy openings. Using smaller sampling units (6.25 m2 rather than 25 m2) and waiting until year 5 may be more useful for making such predictions. In addition, there was an important turnover in vertical dominance in these openings. Non-commercial woody competitors were frequently dominant in early years but were often replaced by commercial hardwoods, notably yellow birch. We propose certain thresholds for assessing the success of post-harvest regeneration and for evaluating the need for a cleaning treatment.
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Elgamal, Sara Gamal, Jealan M. El-Shafei, Hassan Mohamed El-Said Azzazy, Reham Ali Dwedar, and Sherif Adel El-Khodary. "Evaluation of the Antimicrobial Effect of Pre-Synthesized Novel Antibiotic Electrospun Nanofibers as an Intracanal Delivery Strategy for Regenerative Endodontics: A Randomized Clinical Trial." Open Access Macedonian Journal of Medical Sciences 10, no. D (June 2, 2022): 303–10. http://dx.doi.org/10.3889/oamjms.2022.9750.
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AIM: The aim of this study is to evaluate the antimicrobial effect of pre-synthesized novel antibiotic loaded electrospun nanofibers and compare it with conventional triple antibiotic paste when used in patients with immature necrotic teeth. METHODS: Antibiotic loaded nanofibers were fabricated by electrospinning. Thirty-four patients with immature necrotic teeth were included in the study. In the first visit, access cavity preparation was performed to obtain the first bacteriological sample (S1). The canals were thoroughly irrigated using sodium hypochlorite 1.5% and a second sampling was performed (S2). Patients were randomly divided into two groups according to the intracanal medicament used: Modified triple antibiotic paste (MTAP) loaded electrospun nanofibers or MTAP paste. At the second appointment, the third samples (S3) were taken. The intracanal bacterial count was determined using the spread plate culture technique. Scanning electron microscopy (SEM) was used to examine the morphology of the fabricated MTAP loaded electrospun nanofibers. RESULTS: Both MTAP nanofibers and MTAP paste resulted in significant reduction of bacterial count after the irrigation step. MTAP nanofibers resulted in significantly higher percent reduction of bacterial count (p < 0.05). CONCLUSIONS: It was concluded that electrospinning technology can be used to fabricate antibiotic containing nanofibers which can results in enhanced disinfection in regenerative endodontic procedures.
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Bentancor Araujo, Ana Claudia, Helio Junior Bentancor Araujo, Edenir Luis Grimm, and Solon Jonas Longhi. "RELATIONSHIP BETWEEN ARBOREAL, TOPOGRAPHIC, AND EDAPHIC STRUCTURES IN A STRETCH OF A RIPARIAN FOREST IN THE PAMPA BIOME, RIO GRANDE DO SUL, BRAZIL." FLORESTA 49, no. 4 (September 19, 2019): 773. http://dx.doi.org/10.5380/rf.v49i4.59167.
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Despite the considerable loss of natural area in the Pampa biome, the number of scientific studies carried out here is low; it is lower in terms of natural regeneration. Therefore, the present study analyzed arboreal shrub and natural regeneration as well as the influence of environmental variables on the distribution of a riverine forest of the Espinilho stream in the Pampa biome, Rio Grande do Sul. A hundred plots were systematically set for arboreal shrub sampling. To evaluate the regenerating component, two classes were established: Class I and Class II. The main species in the arboreal shrub were Ocotea acutifolia (Nees) Mez and Pouteria salicifolia (Spreng.) Radlk., while those in natural regeneration were Eugenia uniflora L. and Blepharocalyx salicifolius (Kunth) O.Berg. The characteristics of the relief, soil, and canopy conditioned the species of the arboreal shrub and regenerating strata.
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Jannat, Morgubatul, Md Kamruzzaman, and Mohammed Kamal Hossain. "Assessment of Natural Regeneration Potential of Native Tree Species in a Community Managed Forest of Bangladesh." International Journal of Environment 9, no. 1 (February 9, 2020): 100–114. http://dx.doi.org/10.3126/ije.v9i1.27598.
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The study was conducted to explore natural regeneration potential of a community managed forest. Village Common Forest (VCF) has been managed as a commo n property resource under the leadership of Mouza Headmen based on traditional resource management pattern. Stratified random sampling method was carried out for the inventory of the regeneration status. The sampling plot size for regeneration was 5m × 5m. About 47 regenerating tree species belonging to 22 families were recorded from the studied village common forest where Grewia nervosa was the dominant regenerated seedlings. Euphorbiaceae was the dominant family with 7 species followed by Moraceae (5 species), Rubiaceae (4 species), Anacardiaceae (3 species), Combretaceae (3 species) and Mimosaceae (3 species). Maximum Importance Value Index (IVI) was found for Grewia nervosa (27.97) followed by Brownlowia elata (21.52), Artocarpus chama (14.74) and Leea macrophylla (12.53). A total of 78% of the regenerating tree species were regenerated from seeds and 22% from coppices. Shannon-Wiener’s Diversity Index was found 3.37 where Simpson’s Diversity Index was 0.055, Moreover, Margalef’s Richness Index was calculated as 8.57 and Species Evenness Index was 0.88. The results depict that the regeneration status of studied VCF has been satisfactory and Village Common Forest still contains dense forests that represents rich biodiversity including rare species. The study might be helpful for increasing conservation importance of this forest. This study suggests further study on vegetation structure and carbon pool assessment to understand more about of this forest for future sustainability.
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Vasconcelos, Weuler Alves, Sabrina do Couto de Miranda, Carlos de Melo Silva-Neto, and Priscila Bezerra de Souza. "CARACTERIZAÇÃO FLORÍSTICO-ESTRUTURAL E SÍNDROMES DE DISPERSÃO DE ESPÉCIES LENHOSAS DE REMANESCENTE DE CERRADÃO." Nativa 8, no. 4 (July 31, 2020): 514–22. http://dx.doi.org/10.31413/nativa.v8i4.10048.
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Entender a composição florístico-estrutural e as síndromes de dispersão de um remanescente fornecem subsídios para futuros planos de recuperação e conservação. Desta forma, objetivou-se analisar a composição florística, a estrutura da vegetação lenhosa e as síndromes de dispersão de um remanescente de cerradão localizado em Palmeiras de Goiás, GO. Para tal, foram alocadas 10 parcelas de 20 x 50 m onde todos indivíduos com diâmetro da base (Db) ≥ 5 cm ingressaram na amostragem, sendo medido ainda seu diâmetro à altura do peito (DAP) e altura. Foram amostrados 2.070 indivíduos distribuídos em 109 espécies, 86 gêneros e 49 famílias, sendo Fabaceae a família mais abundante. As espécies Tapirira guianensis e Xylopia aromatica se destacaram em Valor de Importância na área. A distribuição diamétrica apresentou-se no formato de “J”-invertido e a distribuição de altura com tendência normal, mostrando uma comunidade auto regenerativa. A síndrome de dispersão predominante foi a zoocoria, com 55,5% das espécies. Os resultados encontrados corroboram a importância das áreas de reserva legal e a necessidade de sua manutenção como estratégia de conservação/preservação ambiental.Palavras-chave: fitofisionomia florestal; zoocoria; anemocoria; comunidade. FLORISTIC-STRUCTURAL CHARACTERIZATION AND DISPERSION SYNDROMES OF WOODY SPECIES OF CERRADÃO REMANESCENT ABSTRACT:Understanding the floristic-structural composition and the dispersion syndromes of a remnant provides subsidies for future recovery and conservation plans. Thus, the aim was to analyze the floristic composition, woody vegetation structure and dispersion syndromes of a cerradão remnant located in Palmeiras de Goiás, GO. For this, 10 plots of 20 x 50 m were allocated where all individuals with base diameter (Db) ≥ 5 cm entered the sampling, and their diameter at breast height (DAP) and height were also measured. We sampled 2,070 individuals distributed in 109 species, 86 genera and 49 families, Fabaceae being the most abundant family. The species Tapirira guianensis and Xylopia aromatica stood out in Valor de Importância in the area. The diametric distribution was presented as “J”-inverted and the height distribution with normal tendency, showing a self-regenerative community. The predominant dispersion syndrome was zoocoria, with 55.5% of the species. The results found corroborate the importance of the legal reserve areas and the need for their maintenance as a conservation/environmental preservation strategy.Keywords: forest phytophysiognomy; zoochory; anemocory; assembly.
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Myrkassimova, A. S., S. N. Demeuov, and K. Kulanbay. "Phenology of elm seed bug (Arocatus melanocephalus) in Almaty City of Southeastern Kazakhstan." SABRAO Journal of Breeding and Genetics 54, no. 1 (March 31, 2022): 193–200. http://dx.doi.org/10.54910/sabrao2022.54.1.18.
Full textAbstract:
The phenology of the elm seed bug (Arocatus melanocephalus) and the effects of environmental factors on its population dynamics were studied during the months of May and June from 2016 to 2019 in the Almaty region, Kazakhstan. The study comprised the sampling of 15 elm trees at 10 different selected sites. The insects were caught using entomological nets for population dynamics studies. The extent of leaf damage was determined by measuring the damaged square area using Blunk’s formula. In the Almaty region, the elm seed bug laid eggs in mid-April, and the imago appeared in mid-June. The insect laid eggs on the regenerative organs of the elm trees and caused significant damage to the leaves, ranging from 60%–95%. However, the significant leaf damage was not caused by the said elm trees insect as what is common in other regions of the world. In the Almaty region, the elm tree foliar damage is notably made by bugs. A negative correlation was recorded between the insect population and rainfall during May. The elm seed bug reproduction and growth occurred, and population size grew during May and June, but, no correlation was found on temperature for these two months. The present results would help in understanding the phenology and population dynamics of the elm seed bug and design the strategies for its control.
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Buggert, Marcus, Son Nguyen, Samuel Darko, Amy Ransier, Daniel Douek, Niklas K. Björkström, Yoav Dori, Max G. Itkin, and Michael R. Betts. "Identity of recirculating T cells i humans." Journal of Immunology 202, no. 1_Supplement (May 1, 2019): 189.7. http://dx.doi.org/10.4049/jimmunol.202.supp.189.7.
Full textAbstract:
Abstract Memory T cells are widely considered to continually recirculate between tissues and blood via lymph to maintain immunosurveillance. While much effort has been dedicated to understand which memory T cells that are present in tissues, less is known about peripheral blood memory T cell subsets that recirculate through and egress from tissues during steady-state. Here we directly identify the tissue egressing (recirculating) immune system by sampling thoracic duct lymph (TDL), blood and peripheral tissues in humans and primates. We find that 70% of all immune cells egressing from tissues are T cells. Through transcriptional, functional, clonotypic, and epigenetic profiling, we find that cytolytic memory CD8+ T cell subsets are almost entirely confined to blood, while their phenotypic counterparts in TDL and many tissues represent non-cytolytic cells with higher regenerative capacity. Cytolytic T cells in blood possess a distinct clonotype distribution compared to TDL CCR7- T cells and are retained in blood after treatment with the tissue egress inhibitor fingolimod. We additionally find that HIV-specific CD8+ T cells can be readily found in TDL but again lack a cytolytic phenotype. We propose that cytolytic molecule expression is confined to a blood-resident memory T cell population in steady-state and that the intermediate differentiation status of HIV-specific CD8+ T cells is a fingerprint of their systemic recirculation capacity, rather than dysfunction, in humans.
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Bhuiyan, Md Khayrul Alam, Md Akhter Hossain, Abdul Kadir Ibne Kamal, Mohammed Kamal Hossain, Mohammed Jashimuddin, and Md Khabir Uddin. "Climate resilience through natural regeneration in degraded natural forests of south-eastern hilly region of Bangladesh." Bangladesh Journal of Botany 48, no. 3 (September 30, 2019): 417–25. http://dx.doi.org/10.3329/bjb.v48i3.47720.
Full textAbstract:
A study was conducted by using 5m × 5m sized 179 quadrates following multistage random sampling method for comparative regenerating tree species, quantitative structure, diversity, similarity and climate resilience in the degraded natural forests and plantations of Cox's Bazar North and South Forest Divisions. A total of 70 regenerating tree species were recorded representing maximum (47 species) from degraded natural forests followed by 43 species from 0.5 year 39 species from 1.5 year and 29 species from 2.5 year old plantations. Quantitative structure relating to ecological dominance indicated dominance of Acacia auriculiformis, Grewia nervosa and Lithocarpus elegans seedlings in the plantations whereas seedlings of Aporosa wallichii, Suregada multiflora and Grewia nervosa in degraded natural forests. The degraded natural forests possess higher natural regeneration potential as showed by different diversity indices. The dominance-based cluster analysis showed 2 major cluster of species under one of which multiple sub-clusters of species exists. Poor plant diversity and presence of regenerating exotic species in the plantations indicated poor climate resilience of forest ecosystem in terms of natural regeneration.