Articoli di riviste sul tema "Poudre en suspension"
Segui questo link per vedere altri tipi di pubblicazioni sul tema: Poudre en suspension.
Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili
Vedi i top-50 articoli di riviste per l'attività di ricerca sul tema "Poudre en suspension".
Accanto a ogni fonte nell'elenco di riferimenti c'è un pulsante "Aggiungi alla bibliografia". Premilo e genereremo automaticamente la citazione bibliografica dell'opera scelta nello stile citazionale di cui hai bisogno: APA, MLA, Harvard, Chicago, Vancouver ecc.
Puoi anche scaricare il testo completo della pubblicazione scientifica nel formato .pdf e leggere online l'abstract (il sommario) dell'opera se è presente nei metadati.
Vedi gli articoli di riviste di molte aree scientifiche e compila una bibliografia corretta.
1
Ayele, J., B. Fabre e M. Mazet. "Influence de l'origine et de la nature des substances humiques sur l'adsorption de l'atrazine sur charbon actif en poudre". Revue des sciences de l'eau 6, n. 4 (12 aprile 2005): 381–94. http://dx.doi.org/10.7202/705181ar.
Abstract (sommario):
Les essais d'adsorption sur charbon actif en poudre, de sept acides humiques (H) ou fulviques (F) et pour trois pH (5,6 ; 7,0 ; 8,8) marquent que ces acides ont un comportement différent suivant leur origine. Lorsque le pH de la suspension de charbon est basique, l'adsorption des différentes fractions humiques diminue, ce qui est en relation avec l'augmentation de leur solubilité. Pour un même pH de la suspension, les acides humiques et fulviques d'origine aqueuse s'adsorbent mieux que ceux d'origine commerciale ou que ceux extraits de sol. La capacité maximale d'adsorption de l'atrazine sur charbon actif en poudre : 260 mg.g-1 (Langmuir), est plus fortement diminuée en présence d'acides fulviques que d'acides humiques d'une part, et plus inhibée (jusqu'à 40 %) par les acides fulviques extraits d'eau (F1, F2) que par ceux extraits de sol (F3) d'autre part. Par contre, les acides humiques provenant de substances commerciales (H4, H5) influencent moins l'adsorption de l'atrazine. L'ensemble des essais montre que l'origine et la nature des substances humiques joue un rôle prépondérant sur l'adsorption de l'atrazine sur charbon actif, le pH ayant une influence limitée. Enfin l'étude de l'influence de l'atrazine sur l'adsorption des substances humiques sur charbon actif en poudre indique également une différence de comportement entre les acides fulviques, pour lesquels on note peu de variation, et les acides humiques, pour lesquels on note à la fois une promotion de l'adsorption et une meilleure affinité d'adsorption sur le charbon actif en poudre en présence d'atrazine. Ce travail met en évidence l'importance du choix des substances humiques pour des essais d'évaluation des interactions substances humiques - pesticides lors de l'adsorption sur charbon actif en poudre.
2
Ayele,, J., A. Mahi e M. Mazet. "Influence du dodécylsulfate de sodium sur l'adsorption des acides humiques sur charbon actif en poudre". Revue des sciences de l'eau 3, n. 4 (12 aprile 2005): 425–39. http://dx.doi.org/10.7202/705083ar.
Abstract (sommario):
L'objectif de ce travail est d'étudier l'influence d'un tensioactif anionique, le dodécylsulfate de sodium (DSS) sur l'adsorption d'acides humiques (AH), sur le charbon actif en poudre (CAP). L'adsorption sur CAP, en fonction du temps, des AH seuls, puis du DSS seul, a été effectuée en réacteur discontinu, à différents pH (7,0 et 10,5). Les mêmes expériences ont été réalisées avec le mélange des deux composés et l'on a pu constater une inhibition réciproque de leur adsorption, moins importante à pH basique (10,5). L'influence de l'ordre d'introduction des coadsorbats, sur l'adsorption de chacun d'eux, a permis de montrer que l'inhibition de l'adsorption des AH sur CAP par le DSS est encore plus importante lorsque les AH sont ajoutés sur une suspension DSS-CAP déjà en équilibre. Aucune désorption du DSS n'a pu être mise en évidence après 24 heures. Ces résultats pourraient permettre de conclure à une adsorption « compétitive » des AH et du DSS sur les mêmes sites superficiels du charbon actif. Ce travail permet de préciser les phénomènes d'adsorption pouvant intervenir entre divers micropolluants susceptibles de s'adsorber simultanément soit sur des sédiments naturels, soit sur charbon actif lors du traitement des eaux naturelles.
3
TOULLEC, R., J. F. GRONGNET, H. FLAGEUL, J. LAREYNIE e P. M. LUCAS. "Remplacement partiel des protéines du lait par celles du blé ou du maïs dans les aliments d’allaitement : influence sur l’utilisation digestive chez le veau de boucherie". INRAE Productions Animales 3, n. 3 (4 luglio 1990): 201–6. http://dx.doi.org/10.20870/productions-animales.1990.3.3.4376.
Abstract (sommario):
Le but de cet essai était d’étudier l’influence du remplacement d’une partie des protéines du lait par celles du blé ou du maïs, sur la digestibilité de l’aliment et la rétention azotée, chez le veau de boucherie. Pour cela, 4 laits de remplacement (T, BV, BD et M) ont été distribués à des lots de 6 veaux entre les âges d’environ 4 et 19 semaines. Dans l’aliment T, les protéines étaient apportées en totalité par de la poudre de lait écrémé. Dans les autres aliments, 19 % des protéines étaient fournies soit par du gluten de blé vital (BV) ou dévitalisé (BD), soit par un concentrat protéique de maïs (M). La digestibilité apparente et la rétention azotée, mesurées au cours des 8e et 14e semaines d’âge, n’ont pas été significativement affectées par la nature des protéines de l’aliment : en moyenne, la digestibilité de l’azote a été de 0,95, 0,95, 0,95 et 0,93 pour les aliments T, BV, BD et M, respectivement. Les valeurs calculées ont été de 0,94, 0,93 et 0,86 pour la digestibilité de l’azote des produits BV, BD et M. Les veaux des lots BV, BD et M ont développé des anticorps systémiques contre les protéines étudiées. Cependant, aucune de ces dernières ne semble avoir entraîné de réactions allergiques. La dévitalisation n’a pas eu d’influence notable sur l’utilisation du gluten de blé par les animaux, mais elle a permis d’améliorer son maintien en suspension.
4
Mechouk, C., A. Hauret, F. Khajehnouri e P. Burnet. "Traitement des micropolluants en station de potabilisation". Techniques Sciences Méthodes, n. 6 (giugno 2019): 51–70. http://dx.doi.org/10.1051/tsm/201906051.
Abstract (sommario):
Dans le cadre de la réhabilitation de l’usine de potabilisation de Saint-Sulpice (Lausanne, Suisse), le service de l’eau de la ville de Lausanne a conduit des essais pilotes afin de choisir la filière de traitement la plus adaptée. L’usine actuelle de 1971 est une filière de traitement simple consistant en une filtration sur sable suivie d’une chloration. Malgré la production d’une eau potable de qualité satisfaisante, la filière actuelle n’est pas capable de faire face aux nouveaux défis du domaine du traitement de l’eau (micropolluants). Les essais pilotes, réalisés entre 2014 et 2017, ont porté sur des technologies améliorant l’abattement des micro-organismes, des matières en suspension (MES) et des micropolluants. Il existe trois méthodes pour abattre les micropolluants : l’adsorption sur charbon actif (CA), la filtration membranaire fine (nanofiltration ou osmose inverse) ou l’oxydation. Trois mises en œuvre de charbon ont été testées : filtration sur CA en grain (CAG), suspension de CA micrograins (CAµG) ou mise en contact de CA poudre (CAP) (sur l’usine de Lutry). Un pilote de nanofiltration a également été testé, ainsi qu’un procédé d’oxydation avancée (AOP), avec de l’ozone et du peroxyde d’hydrogène, suivi d’un filtre CAG. Chaque procédé présente des spécificités qui lui permettent de mieux abattre certaines molécules par rapport à d’autres. L’étude s’est particulièrement focalisée sur l’abattement des trois principaux micropolluants retrouvés en permanence en concentrations les plus élevées dans l’eau du lac Léman : metformine (450 ng/L), 1H-benzotriazole (80 ng/L) et gabapentine (30 ng/L). Hormis une élimination faible du 1H-benzotriazole (35 % environ), la filtration membranaire par nanofiltration ou par osmose inverse basse pression permet des abattements supérieurs à 80 % pour la majorité des micropolluants. L’AOP, couplée avec une filtration sur CAG, permet d’atteindre de bons rendements d’élimination des micropolluants (70 %). L’ozonation des micropolluants engendre des sous-produits, aujourd’hui difficilement identifiables et quantifiables. Globalement, le charbon actif permet un abattement moyen des micropolluants de 20 à 40 % selon sa mise en œuvre. La future filière sera composée autour d’une unité d’ultrafiltration (MES et micro-organismes). Le traitement des micropolluants sera, lui, assuré soit par une étape d’adsorption sur charbon actif, soit par une étape de nanofiltration ou une combinaison des deux. Le traitement par charbon actif pourrait éventuellement être amélioré par le couplage avec un procédé AOP.
5
von Bronk, Tabea, Michael Haist e Ludger Lohaus. "The Influence of Bleeding of Cement Suspensions on Their Rheological Properties". Materials 13, n. 7 (1 aprile 2020): 1609. http://dx.doi.org/10.3390/ma13071609.
Abstract (sommario):
Flowable concretes tend to segregate. The risk of segregation is particularly high when the concrete is vibrated during the compaction process. A well-known segregation phenomenon is the so-called “bleeding”. This is a rise of water to the surface of the freshly poured concrete due to the difference in density between the mixing water and the concrete’s denser solid components (aggregates, cement and additives). This type of segregation occurs particularly within the paste. The focus of this paper is, therefore, on the sedimentation behavior at the microscale of concrete and especially on the influence of this process on rheological properties of the cement paste. In addition to common bleeding tests of cement suspensions using standing cylinders, rheometric measurements were performed on the suspensions during the bleeding process. A measuring procedure was developed for the rheometric measurements of the sedimenting cement suspensions. The rheological properties of the investigated cement suspensions were determined at four specific measuring times and at four specific measuring heights (i.e., positions) each. With this method it could be shown that the cement suspensions are not homogeneous over their height and that bleeding has a great influence on the rheological properties of cement suspension.
6
Nielsen, D. G., e M. J. Dunlap. "Taxus, Control of Black Vine Weevil Larvae, Wooster, Ohio, 1990". Insecticide and Acaricide Tests 17, n. 1 (1 gennaio 1992): 354–55. http://dx.doi.org/10.1093/iat/17.1.354a.
Abstract (sommario):
Abstract Taxus plants, growing in 1 pt (0.47 liter) containers obtained from a nursery in NE OH, were used to evaluate conventional insecticides and entomogenous nematodes against black vine weevil larave. Plants were repotted 12 Jul in 1-gal (3.8 liter) containers using two different media mixes. Medium # 1 contained three parts pine bark and one part peat moss (3:1). Dolomitic lime was added to the mix at 6 lb/cuyd. Medium #2 contained three parts pine bark, one part hardwood bark, and one part peat moss (3:1:1). The Dolomitic lime was added to the hardwood bark by the supplier prior to the mixing of the three components. Plants were fertigated with 100 ppm N, P, K (Peter’s 20-20-20) every Mon, Wed, and Fri. Beginning 1 Aug, water alone was applied via over-head irrigation. Black vine weevil eggs were collected from adults held at 22°C and 80%+ RH and a 16:8 LD. On 3 Aug, all containers received 60 brown eggs, placed 2.54 cm beneath the surface of the potting medium. An additional 69 brown eggs were added to each container 10 Aug, as before. Hatchability was 73 and 81 percent, respectively. Nematode treatments were applied 29 Oct when larval head-capsule width avg 1.7 mm and 20 Nov when head-capsule width avg 1.8 mm. A nematode stock suspension was made by placing 1 unit of BIOSYS (10,000,000 nemas) in 10 gal of water. Nemas were applied volumetrically in 473 ml of water to deliver pre-determined no. of nemas per pot. Nema stock suspensions were thoroughly stirred, and 1 liter of the solution was placed in a capped bottle. The bottle was shaken, a pre-determined vol containing a target no. of nematodes was poured into a graduated cylinder. These measured amt of suspension were placed in pt jars, and water was added to bring the vol to 473 ml. This finished suspension was added to each 1 gal pot. All finished suspensions were poured over the potting medium to achieve even distribution. Other insecticide treatments were applied 10 Sep or 29 Oct by mixing the pre-determined pot rate in 473 ml of water which was poured over the pot medium, as before. All plants were watered prior to and after application. Plants received 2.0 cm of over-head irrigation every Mon, Wed, and Fri. Effects of the first nematode treatment were evaluated 11 Dec. The second nematode treatments, along with the insecticide treatments, were evaluated 17 Dec, by removing the plant and medium from each container, counting the no. of larvae, and recording their condition. Some pupation was occurring when evaluations were made.
7
Nielsen, D. G., e M. J. Dunlap. "Taxus, Control of Black Vine Weevil (BVW) Larvae, Wooster, Ohio, 1989". Insecticide and Acaricide Tests 16, n. 1 (1 gennaio 1991): 260. http://dx.doi.org/10.1093/iat/16.1.260.
Abstract (sommario):
Abstract Taxus plants, growing in 1 pint (0.47 liter) containers obtained from a nursery in NE Ohio, were used to evaluate conventional insecticides and entomogenous nematodes against BVW larvae. Plants were repotted 27 Jun in 1 gal (3.9 liter) containers with a 3:1 (pine barkipeat) medium mix. Dolomitic lime was added to the mix at 6 lb/cuyd. Plants were fertigated with 200 ppm N, P, K (Peter’s 20-20-20) every Mon, Wed, and Fri. Beginning 7 Aug, water alone was applied via over-head irrigation. BVW eggs were collected from adults held at 22°C and 80%+ RH and a 16 h photoperiod. On 7 Aug, all containers received 75 brown eggs, placed 2.54 cm beneath the surface of the potting medium. An additional 58 brown eggs were placed 16 Aug, as before. Hatchability was 89 and 77 percent, respectively. Treatments were applied 8 Nov when larval head-capsule width averaged 1.63 mm. A nematode stock suspension was made by placing 1 unit of Otinem (50,000,000 nemas) in 10 gallons of water. Nemas were applied volumetrically in 473 ml of water to deliver predetermined numbers of nemas per pot. AgSorb flake (2.4 grams) was added to the finished suspension for each pot of selected treatments. All finished suspensions were mixed thoroughly in a pint jar and poured over the potting medium to achieve even distribution. Other insecticide treatments were applied by mixing the predetermined pot rate in 473 ml of water which was poured over the pot medium, as before. All plants were watered prior to and after application. Plants were then hand watered every Mon, Wed, and Fri. Treatment effects were evaluated 28-29 Nov, when larvae were nearing maturity, by removing the plant and medium from each container and counting the number of larvae and recording their condition. Some pupation was occurring when evaluations were made.
8
Letord-Quemere, M. M., F. Coeuret e J. Legrand. "Traitement anodique de suspensions de poudre de graphite sur des �lectrodes de m�tal d�ploy�". Journal of Applied Electrochemistry 17, n. 5 (settembre 1987): 965–76. http://dx.doi.org/10.1007/bf01024363.
9
Mashkour, Mahdi, Mehdi Tajvidi, Tsunehisa Kimura, Fumiko Kimura e Ghanbar Ebrahimi. "Fabricating unidirectional magnetic papers using permanent magnets to align magnetic nanoparticle covered natural cellulose fibers". BioResources 6, n. 4 (28 settembre 2011): 4731–38. http://dx.doi.org/10.15376/biores.6.4.4731-4738.
Abstract (sommario):
This paper reports a simple innovative method to align magnetic cellulose fibers by using a simple permanent magnet to fabricate unidirectional magnetic papers. Magnetic cellulose fibers were made by in situ synthesis of magnetite nanoparticles on alpha cellulose pulp extracted from American southern pine. Scanning electron microscope micrographs and energy dispersive X-ray spectroscopy maps indicated that magnetite nanoparticles completely covered the cellulose fibers. Suspensions of magnetic cellulose fibers were prepared at three levels of concentration (0.02, 0.04, and 0.08 g/L) and poured into the designed magnetic forming machine. Flow rate of suspension into the forming column was adjusted at 0, 0.3, 0.5, and 1 cm/s. The strength of the applied external magnetic field was the same in all cases and lower than 0.18 T. Orientation analysis indicated that the designed magnetic forming machine has a high performance to be used for aligning magnetic cellulose fibers and fabricating unidirectional magnetic cellulose papers. Observed anisotropic magnetic and mechanical properties confirmed the unidirectional structure.
10
Pezda, J. "Heat Treatment of a Casting Element of a Through Clamp to Suspension of Electric Cables on Line Post Insulators". Archives of Foundry Engineering 16, n. 3 (1 settembre 2016): 89–94. http://dx.doi.org/10.1515/afe-2016-0056.
Abstract (sommario):
Abstract Heat treatment of a casting elements poured from silumins belongs to technological processes aimed mainly at change of their mechanical properties in solid state, inducing predetermined structural changes, which are based on precipitation processes (structural strengthening of the material), being a derivative of temperature and duration of solutioning and ageing operations. The subject-matter of this paper is the issue concerning implementation of a heat treatment process, basing on selection of dispersion hardening parameters to assure improvement of technological quality in terms of mechanical properties of a clamping element of energy network suspension, poured from hypoeutectic silumin of the LM25 brand; performed on the basis of experimental research program with use of the ATD method, serving to determination of temperature range of solutioning and ageing treatments. The heat treatment performed in laboratory conditions on a component of energy network suspension has enabled increase of the tensile strength Rm and the hardness HB with about 60-70% comparing to the casting without the heat treatment, when the casting was solutioned at temperature 520 °C for 1 hour and aged at temperature 165 °C during 3 hours.
11
Yamamoto, Kota, e Shigehiro Hashimoto. "Cell Sorting Using Diagonal Bottom Grooves in a Microchannel". Journal of Systemics, Cybernetics and Informatics 22, n. 2 (aprile 2024): 48–53. http://dx.doi.org/10.54808/jsci.22.02.48.
Abstract (sommario):
Cell shape is related to cell function. For the purpose of cell sorting based on shape, a channel with diagonal grooves on the bottom was designed. A cell suspension was poured into a channel created by micromachining, and cell sorting according to shape was confirmed. Experimental results shows that smaller and more elongated cells undergo a larger shift perpendicular to the mainstream direction during passing over the groove. Diagonal bottom grooves in a microchannel are effective for cell sorting.
12
Golak, Slawomir. "Manufacture of Locally Reinforced Composite Discs by Casting in the Alternating Electromagnetic Field". Advances in Materials Science and Engineering 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/681939.
Abstract (sommario):
The paper discusses a new method of obtaining local particle reinforcement in the composite discs. In this method, the liquid composite suspension is poured into a mould and then exposed to the alternating electromagnetic field. The Lorentz force acting on the liquid metal causes the reinforcement to move towards one or both surfaces of the manufactured disc. The paper presents the process theory, the methodology for the casting system design, and the results of an experimental manufacture of one-side and two-side reinforced composite discs made of aluminium alloy.
13
Aburaya, Kazuaki, Chiaki Tsuboi, Fumiko Kimura, Kenji Matsumoto, Masataka Maeyama e Tsunehisa Kimura. "X-Ray Diffraction from Magnetically Oriented Microcrystal Suspension". Acta Crystallographica Section A Foundations and Advances 70, a1 (5 agosto 2014): C1136. http://dx.doi.org/10.1107/s2053273314088639.
Abstract (sommario):
A three dimensionally magnetically oriented microcrystal array (3D-MOMA) is attractive to determination of a crystal structure as well as a molecular structure because it does not require a single crystal with sufficient size and quality for diffraction studies. We have developed a novel method to fabricate 3D-MOMA and determined several crystal structures using the 3D-MOMAs[1],[2]. However, the structure determination through MOMA requires a solidification treatment with UV curable monomer prior to X-ray diffraction experiment. We have developed a new X-ray diffractometer equipped with a magnetic field generator, which makes it possible to collect diffraction data without the solidification treatment. In this poster, we describe X-ray diffraction analyses of a magnetically oriented microcrystal suspension (MOMS) of L-alanine without the solidification treatment. A suspension of L-alanine microcrystals was poured in a glass capillary and rotated at a constant speed in a magnetic circuit attached in the X-ray diffractometer. Then, diffraction images were collected every 60 seconds. In the initial phase, the diffraction pattern showed a broad shape similar to that from a powder sample. As time goes on, diffraction patterns have gradually changed to single-crystal like patterns. After 2 hours, the shape of diffraction spots became as sharp as that of a single crystal. This observation shows that the microcrystals are oriented in the same direction. Owing to the improvement of the magnetic circuit and X-ray diffractometer, the quality of the diffraction has been greatly improved compared to that reported previously[3]. Further details of the analyses will be shown in the poster.
14
SHIMAKITA, TOMONORI, YOSHIKAZU TASHIRO, AKIRA KATSUYA, MIKAKO SAITO e HIDEAKI MATSUOKA. "Rapid Separation and Counting of Viable Microbial Cells in Food by Nonculture Method with Bioplorer, a Focusing-Free Microscopic Apparatus with a Novel Cell Separation Unit". Journal of Food Protection 69, n. 1 (1 gennaio 2006): 170–76. http://dx.doi.org/10.4315/0362-028x-69.1.170.
Abstract (sommario):
A nonculture method utilizing a novel apparatus, the bioplorer, was developed. The bioplorer is composed of an efficient cell separation unit, a focusing-free microscopic device, and an image analysis program. A meat or vegetable suspension is poured into the cell separation funnel, and insoluble matter in the sample suspension is trapped by prefilters. Microbial cells passing through the two prefilters are then trapped by the membrane filter (pore size, 0.4 μm). Trapped cells are double-stained with 4′,6′-diamidino-2-phenylindole and propidium iodide, and the membrane filter is removed and set on the focusing-free microscope. A fluorescent image is then recorded. Total numbers of viable and dead cells on the membrane filter can thus be determined automatically. One assay can be performed within 10 min, which is much faster than the culture method. The results obtained with both the nonculture method and the culture method for meat and vegetable samples were highly correlated (r = 0.953 to 0.998). This method is feasible for the practical purpose of food safety control.
15
Chakraborty, Ayan, Mohini Sain, Mark Kortschot e Sean Cutler. "Dispersion of Wood Microfibers in a Matrix of Thermoplastic Starch and Starch–Polylactic Acid Blend". Journal of Biobased Materials and Bioenergy 1, n. 1 (1 aprile 2007): 71–77. http://dx.doi.org/10.1166/jbmb.2007.1980.
Abstract (sommario):
The successful dispersion of cellulose fibers of submicrometer diameter in polymers has been restricted to solution-cast films so far. In this work, the dispersion of microfibers in biopolymers was investigated by melt-mixing using conventional processing equipment. Thermoplastic starch and a blend of starch and polylactic acid (PLA) were used as matrix materials. A suspension of cellulose microfibers less than 1 μm in diameter was prepared in water. This microfiber suspension was poured into molten thermoplastic starch to obtain fiber loadings up to 2%. The composites were compression molded into thin films roughly 0.25 mm thick. there was a 10% increase in tensile strength and a 50% increase in stiffness with each percentage increase in microfiber loading in the starch polymer. Similar improvement in tensile properties was also noted for a polymer system prepared by blending starch and PLA. Laser confocal microscopy images were analyzed to quantify microfiber dispersion at different composite processing parameters. This was the first work where successful dispersion of cellulose fibers of submicrometer was achieved in a composite prepared solely by the melt-mixing process.
16
Franks, George V., France Chabert e Enric Santanach Carreras. "Development of Near Net Shape Forming Processes of Ceramic Parts by Colloidal Processing". Advances in Science and Technology 45 (ottobre 2006): 374–81. http://dx.doi.org/10.4028/www.scientific.net/ast.45.374.
Abstract (sommario):
Techniques for producing near net shape ceramic components using aqueous forming processes are reviewed. Particular focus is on three dimensional, complex shape forming by gel casting and thin film forming by tape casting. Recent progress has been made in formulations that rely on dispersion of submicron ceramic particles in aqueous solutions containing polymers such as chitosan or poly vinyl alcohol and a temperature activated crosslinking agent (DHF, 2,5-dimethoxy- 2,5-dihydrofuran). These formulations can be produced to have low viscosity so that they can either be poured or injected into complex shape molds or cast into tapes. After casting, the suspension is heated to about 70 oC to activate the crosslinking agent. During crosslinking of the polymer, the rheological and mechanical behavior of the suspension is changed from liquid-like to solid-like. This allows the complex shaped bodies to be removed from the mold, dried and sintered. The strengthening of the cast tape due to crosslinking the polymer allows it to be dried without cracking. Rheological and mechanical behaviour, green and fired densities as well as examples of formed components will be presented. The green bodies can be readily machined with common high speed tool steel tools.
17
Nielsen, D. G., e M. J. Dunlap. "Scotch Pine, Control of Northern Pine Weevil, Carrol Co., Ohio, 1989". Insecticide and Acaricide Tests 16, n. 1 (1 gennaio 1991): 276. http://dx.doi.org/10.1093/iat/16.1.276.
Abstract (sommario):
Abstract Scotch pine stumps, cut during the 1988 Christmas tree season at a plantation in Carroll Co., were used to evaluate an entomogenous nematode and an insecticide against northern pine weevil. Applications were made 28 Apr under cloudy skies, 10°C, and no wind. Slight rainfall occurred during application of treatments. A stock suspension of nematodes was prepared by placing 1 unit of Otinem (50,000,000 nemas) in 10 gal of water. Nemas were applied volumetrically in 4 pt of water to deliver predetermined numbers of nemas/stump. AgSorb flake was added (7.6 g) to half of the nematode treatments. Stock suspension was stirred thoroughly prior to removing measured amounts. Finished material was also stirred thoroughly in a sprinkling can and poured over and around each stump to achieve thorough coverage. Lindane was added to kerosene in a Hudson sprayer, and 100 ml of finished spray were applied to each stump. Each treatment was replicated 3 times with each replicate consisting of 5 stumps. Treatments were evaluated 24 Oct by counting the number of chip cocoons exposed by removing the bark from each stump to the first lateral root.
18
Blazutti Marçal, Rubens Lincoln Santana, Daniel Navarro da Rocha e Marcelo Henrique Prado da Silva. "Slip Casting Used as a Forming Technique for Hydroxyapatite Processing". Key Engineering Materials 720 (novembre 2016): 219–22. http://dx.doi.org/10.4028/www.scientific.net/kem.720.219.
Abstract (sommario):
Ceramic materials have particular properties when compared to other classes of materials, exhibiting poor ductility as an example. Slip casting is a widely used ceramic forming technique, and already established in the literature and in the ceramic industry. This study aims to present slip casting as a processing route for producing hydroxyapatite (HA) struts, and show the thermal phase stability. The ceramic suspension was produced and stabilized with hydroxyapatite powder, deionized water and polyethylene glycol 400. The slip was poured into gypsum mold. The green bodies were heat treated at 900 and 1100°C. Hydroxyapatite was the only phase present in all samples, before and after heat treatments. Density measurements showed that the densification was higher for the ceramic bodies sintered at 1100°C, when compared to the ones calcined at 900°C.
19
Codou, Amandine, Nathanaël Guigo, Jesper Gabriël van Berkel, Ed de Jong e Nicolas Sbirrazzuoli. "Preparation and characterization of poly(ethylene 2,5-furandicarboxylate/nanocrystalline cellulose composites via solvent casting". Journal of Polymer Engineering 37, n. 9 (27 novembre 2017): 869–78. http://dx.doi.org/10.1515/polyeng-2017-0042.
Abstract (sommario):
AbstractThe effect of nanocrystalline cellulose dispersion on the nonisothermal crystallization of poly(ethylene 2,5-furandicarboxylate) (PEF) has been investigated by means of solvent casting. The cellulose dispersion plays a significant role on the crystallization temperature, thus dispersive equipments of increasing energies were employed to improve the cellulose particles disaggregation. Therefore, ultra-sonic bath, ultra-sonication, and ultra-turrax were used to disperse cellulose nanocrystals in 1,1,1,3,3,3-hexafluoro-2-propanol. Dissolved separately in the same solvent, PEF was then poured into the cellulose suspension before casting. The cellulose whiskers were inspected by transmission electron microscopy. Differential scanning calorimetry was used to measure the crystallization temperature, while scanning electron microscopy visualized the cellulose dispersion at the fracture surface. After investigation on the interaction of cellulose/PEF via Fourier transform infrared spectroscopy, the thermal stability of the blends was measured by means of thermogravimetric analysis.
20
Shahshojaei, Mona, Hossein Behniafar e Masoud Shaabanzadeh. "Preparation and Characterization of Polystyrene/TiO2 Core-Shell Nanospheres via Suspension Technique". Advanced Materials Research 829 (novembre 2013): 120–25. http://dx.doi.org/10.4028/www.scientific.net/amr.829.120.
Abstract (sommario):
In the present work, at first, nanoTiO2particles in anatase form were effectively surface modified via reacting with NCO groups of 4,4-methylenediphenyl disocyanate (MDI). Secondly, a solution of azobisisobutyronitrile (AIBN) (0.1 g) in inhibitor-free styrene (10 g) was poured into a 150 mL flask containing poly (vinyl alcohol) (PVA) suspending agent (0.1 g) in deionized water (60 mL) under N2flow, while stirring. The reaction mixture was then heated to 80 °C, and stirred for another 1 h. Next, it was divided to two portions; one for the synthesis of pure PS, and the other for the synthesis of PS/TiO2nanocomposites. Each aqueous portion was individually mixed with dichloromethane in a separating funnel. For PS/TiO2nanocomposites, the organic phase was charged with nanoTiO2particles (MDI-treated and/or untreated) (0.05 g), and then fully homogenized using ultrasonic homogenizer. Methanol non solvent was eventually used to precipitate the products. All samples involving pure PS, PS/surface modified TiO2nanocomposite, and PS/surface unmodified TiO2nanocomposite were thoroughly washed, filtered, and dried in vacuum at 50 °C for 12 h. From SEM images a core-shell relation could be clearly detected between the nanoTiO2particles and PS matrix. Meanwhile, the surface modified TiO2was dispersed into the PS matrix with better homogeneity compared to that of unmodified one. Undoubtedly, beside the surface modification factor, PVA suspending agent as an effective nanosized particle stabilizer, too, played a basic role in this high homogeneity. Also, FT-IR and XRD analyses led to promising results.
21
Tragazikis, Ilias K., Theodoti Z. Kordatou, Dimitrios A. Exarchos, Panagiota T. Dalla e Theodore E. Matikas. "Monitoring the Hydration Process in Carbon Nanotube Reinforced Cement-Based Composites Using Nonlinear Elastic Waves". Applied Sciences 11, n. 4 (15 febbraio 2021): 1720. http://dx.doi.org/10.3390/app11041720.
Abstract (sommario):
There is currently an increased need for associating construction material properties and behavior with the nature of their microstructure. One of the major issues in this context is the need for understanding the curing process in freshly poured cement-based materials. This is particularly important when nanoreinforcement materials, such as carbon nanotubes, are used to enhance the mechanical behavior and multifunctionality of the final structure. The solidification point, at which the state of liquid suspension transmutes to the solid state, is of particular interest since it greatly influences the load-bearing capacity of the cement-based material and its structural behavior at the long term. The main purpose of the present work is to develop a reliable method for monitoring the hydration process during the early stages of freshly poured cementitious composites enhanced with carbon nanotubes. This methodology is based on the use of nonlinear elastic waves. To achieve this goal, a combination of contact ultrasonics with noncontact optical detection was used. The detection method for evaluating the setting process is based on the assessment of higher-harmonic amplitudes of an ultrasonic wave, with a given frequency, propagating through the cementitious material. It was observed that the material nonlinearity changes significantly during the hardening process, compared to velocity or attenuation measurements which are based on linear acoustics. These changes were more noticeable as the concentration of carbon nanotubes in the cement matrix increases, indicating that higher harmonics are more susceptible to minute microstructural changes.
22
Dokuchaeva, Anna A., Sergey V. Vladimirov, Vsevolod P. Borodin, Elena V. Karpova, Andrey A. Vaver, Gleb E. Shiliaev, Dmitry S. Chebochakov et al. "Influence of Single-Wall Carbon Nanotube Suspension on the Mechanical Properties of Polymeric Films and Electrospun Scaffolds". International Journal of Molecular Sciences 24, n. 13 (4 luglio 2023): 11092. http://dx.doi.org/10.3390/ijms241311092.
Abstract (sommario):
Carbon nanotubes (CNTs) are used in applications ranging from electrical engineering to medical device manufacturing. It is well known that the addition of nanotubes can influence the mechanical properties of various industrial materials, including plastics. Electrospinning is a popular method for fabricating nanomaterials, widely suggested for polymer scaffold manufacturing. In this study, we aimed to describe the influence of single-walled carbon nanotube (SWCNT) suspensions on polymeric poured films and electrospun scaffolds and to investigate their structural and mechanical properties obtained from various compositions. To obtain films and electrospun scaffolds of 8 mm diameter, we used poly-ε-caprolactone (PCL) and poly(cyclohexene carbonate) (PCHC) solutions containing several mass fractions of SWCNT. The samples were characterized using tensile tests, atomic force and scanning electronic microscopy (AFM and SEM). All the studied SWCNT concentrations were shown to decrease the extensibility and strength of electrospun scaffolds, so SWCNT use was considered unsuitable for this technique. The 0.01% mass fraction of SWCNT in PCL films increased the polymer strength, while fractions of 0.03% and more significantly decreased the polymer strength and extensibility compared to the undoped polymer. The PHCH polymeric films showed a similar behavior with an extremum at 0.02% concentration for strength at break.
23
Khan, S., SMA Feroz e A. Bhoyar. "Comparative Evaluation of Antibacterial Effect of Dental Luting Cements on Streptococcus mutans and Lactobacillus acidophilus: An in vitro Study". Journal of Contemporary Dental Practice 17, n. 12 (2016): 973–77. http://dx.doi.org/10.5005/jp-journals-10024-1966.
Abstract (sommario):
ABSTRACT Introduction This study aimed at evaluating and comparing the antibacterial activity of six types of dental luting cements on Streptococcus mutans and Lactobacillus acidophilus using the agar diffusion test (ADT) and the direct-contact test (DCT). The antibacterial activity in ADT was measured based on the diameter of the zone of inhibition formed, whereas in DCT the density of the bacterial suspension was measured. The lower the density of the suspension, the more antibacterial activity the cement possesses. Materials and methods Agar diffusion test was carried out on the bacteria. After an incubation period of 24 hours, the plates were checked for the presence of zone of inhibition. In DCT the cement was mixed and applied. Once the cement was set, bacterial suspension and brain–heart infusion medium was poured and incubated for 24 hours. After 24 hours, the plate was placed in the enzyme-linked immunosorbent assay plate reader, which measured the optical density of the fluid. The first set of data was recorded approximately 1 hour after incubation. Overall, three sets of data were recorded. Additional experiments were performed on set test materials that were allowed to age for 24 hours, 1 week, 1, 3, and 6 months. Results When using ADT only two cements zinc oxide eugenol (ZOE) and zinc polycarboxylate (ZPC) cement showed antibacterial activity against the test organisms. When using DCT, all cements showed some amount of antibacterial activity. Zinc oxide eugenol and ZPC cement showed highest amount of antibacterial activity against S. mutans and L. acidophilus respectively. Conclusion Within the limitations of study, ZOE cement and ZPC cement were most effective against the tested microorganisms followed by the newer resin cement. The glass ionomer cement was the weakest of all. Clinical significance Patients with high caries index can be treated more effectively using the abovementioned cements. How to cite this article Feroz SMA, Bhoyar A, Khan S. Comparative Evaluation of Antibacterial Effect of Dental Luting Cements on Streptococcus mutans and Lactobacillus acidophilus: An in vitro Study. J Contemp Dent Pract 2016;17(12):973-977.
24
Tsuboi, Chiaki, Kazuki Aburaya, Shingo Higuchi, Fumiko Kimura, Masataka Maeyama e Tsunehisa Kimura. "X-Ray Single Crystal Structural Analysis of Magnetically Oriented Microcrystals". Acta Crystallographica Section A Foundations and Advances 70, a1 (5 agosto 2014): C1138. http://dx.doi.org/10.1107/s2053273314088615.
Abstract (sommario):
We have developed magnetically oriented microcrystal array (MOMA) technique that enables single crystal X-ray diffraction analyses from microcrystalline powder. In this method, microcrystals suspended in a UV-curable monomer matrix are there-dimensionally aligned by special rotating magnetic field, followed by consolidation of the matrix by photopolymerization. From thus achieved MOMAs, we have been succeeded in crystal structure analysis for some substances [1, 2]. Though MOMA method is an effective technique, it has some problems as follows: in a MOMA, the alignment is deteriorated during the consolidation process. In addition, the sample microcrystals cannot be recovered from a MOMA. To overcome these problems, we performed an in-situ X-ray diffraction measurement using a three-dimensional magnetically oriented microcrystal suspension (3D MOMS) of L-alanine. An experimental setting of the in-situ X-ray measurement of MOMS is schematically shown in the figure. L-alanine microcrystal suspension was poured into a glass capillary and placed on the rotating unit equipped with a pair of neodymium magnets. Rotating X-ray chopper with 10°-slits was placed between the collimator and the suspension. By using this chopper, it was possible to expose the X-ray only when the rotating MOMS makes a specific direction with respect to the impinging X-ray. This has the same effect as the omega oscillation in conventional single crystal measurement. A total of 22 XRD images of 10° increments from 0° to 220° were obtained. The data set was processed by using conventional software to obtain three-dimensional molecular structure of L-alanine. The structure is in good agreement with that reported for the single crystal. R1 and wR2 were 6.53 and 17.4 %, respectively. RMSD value between the determined molecular structure and the reported one was 0.0045 Å. From this result, we conclude that this method can be effective and practical to be used widely for crystal structure analyses.
25
Anwar ul Haq, Muhammad Shahid, Muhammad Zeeshan Niaz, Kamra Mahmood, Ussama Yaseen e Muhammad Tariq Adnan Khan. "Evaluation of Nematicidal Potential of Plant Growth Promoting Rhizobacteria against Meloidogyne incognita". Plant Bulletin 1, n. 2 (30 dicembre 2022): 83–90. http://dx.doi.org/10.55627/pbulletin.001.02.0222.
Abstract (sommario):
Root-knot nematodes have a wide host range, causing damage to many annual and perennial crops. More than 100 species of Meloidogyne are known in which M. incognita (Kofoid and White) Chitwood is one of the most common and important plant parasitic nematode in tropical and subtropical regions of the world including Pakistan. Therefore, the present study was planned to check the effect of PGPRs on juvenile mortality and egg hatching inhibition of M. incognita under lab conditions. Eggs were isolated from egg masses by using NaOCl solution. Rhizobacteria (Bacillus subtilis, Pseudomonas fluorescens, Azotobacter chroococcum, Azospirillum sp., Rhizobium leguminosarum) were multiplied on nutrient broth and kept overnight at 28 ± 2 °C in shaking incubator. Cell free culture filtrates were obtained in falcon tubes by centrifuging PGPRs @ 4000 RPM twice for 30 minutes. Two ml of toxins of each PGPR was poured into each 5cm-dia. petri plate and 100 microliters of egg suspension containing approximately 100 eggs were put in each petri plate. Similar experimental conditions and protocols were used for juveniles’ mortality. In this experiment, instead of eggs, 100 J2s contained in 100 microliters of juvenile suspension were put in each petri plate. The petri plates were placed in completely randomized design in incubator at 28 ± 2 °C with ten replicates. Petri dishes containing distilled water were kept under control. All the PGPRs caused larval mortality and inhibition in egg hatching with varying degrees. The maximum egg hatching was inhibited by Bacillus subtilis while Rhizobium leguminosarum was found the least effective. The other PGPRs i.e. Pseudomonas fluorescens, Azotobacter chroococcum, and Azospirillum sp. showed intermediate results.
26
Ortega, Fernando dos Santos, R. L. S. Oliveira, M. C. Plínio e Bernardo N. Nobrega. "Gelcasting of Stainless Steel Powder: An Alternative to Injection Molding". Materials Science Forum 660-661 (ottobre 2010): 194–99. http://dx.doi.org/10.4028/www.scientific.net/msf.660-661.194.
Abstract (sommario):
The gelcasting process is a forming technique originally developed for the shaping of advanced ceramics into final products in attempts to overcome some of the limitations of conventional forming techniques used in powder metallurgy. It is based on preparing a high solids loading suspension of powder dispersed in an aqueous organic monomers solution, which is poured into a mold and gelled through a chemically initiated polymerization. This work describes the gelcasting of HK-30 stainless steel, a type of powder commonly processed by injection molding. Large (70 x 30 mm) and geometrically complex green compacts with outstanding form retention and stability were obtained. Sintered parts showed good surface finishing and reached 96% of theoretical density, yield strength of 418.5 MPa, and ultimate strength of 701.5 MPa. These results compare favorably with those typically obtained through conventional powder injection molding of HK-30 feedstocks. They support the growing view that gelcasting may soon become an industrial, low cost alternative for near net shaping metallic powders into small or large parts with complex geometries
27
Suherman, Hendra, Jaafar Sahari e Abu Bakar Sulong. "Electrical Conductivity and Micro Hardness of Synthetic and Natural Graphite Epoxy Composite". Key Engineering Materials 447-448 (settembre 2010): 614–18. http://dx.doi.org/10.4028/www.scientific.net/kem.447-448.614.
Abstract (sommario):
This study investigates the electrical conductivity and micro hardness of synthetic and natural graphite epoxy composite. Graphite used on this study is synthetic graphite (SG) and natural graphite (NG) with particle size 44m and 30m, respectively. Different graphite concentrations (50 ~ 80 wt.%) were added into the epoxy resin. The dispersion of graphite in epoxy resin was conducted by high speed mixer through mechanical shearing mechanism, its graphite epoxy suspension was poured into the mold and compression molding was conducted for fabrication of graphite epoxy composites. Electrical conductivity was measured by the four point probe. Microscopic analyses conducted on fracture surface use scanning electron microscopic. Results reveal that non conductive epoxy polymer becomes conductor as addition of graphite. Electrical conductivity of NG higher than SG at the same weight percentage (Wt. %) of conducting filler loading. The highest loading concentration, it exhibited values 12.6 S/cm and 7 S/cm at (80 Wt. %). Hardness property of epoxy composites of both type of graphite increase continuously and reached peak at 60 wt% for NG and 70 wt % for SG, while more addition decreased it.
28
Medeiros, Jeane E. de, Rosa de LR Mariano, Elvira MR Pedrosa e Elineide B. da Silveira. "Inconsistency of the biological control of Meloidogyne incognita race 2 in melon by endophytic bacteria". Horticultura Brasileira 27, n. 3 (settembre 2009): 319–24. http://dx.doi.org/10.1590/s0102-05362009000300010.
Abstract (sommario):
We obtained 61 rhizobacterium isolates from rhizosphere soil samples collected in melon commercial fields located in Mossoró, Rio Grande do Norte State, Brazil. These isolates, along with 56 endophytic bacteria from the Collection of Cultures of the Plant Bacteriology Laboratory of the Universidade Federal Rural de Pernambuco, were tested for controlling Meloidogyne incognita race 2 in melon. To infest the soil with nematodes, 1000 eggs of Meloidogyne incognita race 2 per plant were placed in pots where seedlings of the yellow-type melon, cultivar AF 682, were growing for 10 days. Two days before, 20 mL of bacterial suspension (0.7 OD570nm) were poured into each pot. After 60 days, fresh root biomass, gall index, egg mass, and the nematode reproduction factor were assessed. Among the 117 isolates screened, the endophytic Bacillus ENM7, ENM10, and ENM51 were selected because they significantly reduced egg mass and/or gall index. However, when tested again, separately and in mixtures, these isolates nor confirmed their efficiency in vivo, neither affected juvenile emergence in vitro. These results give evidence on the inconsistency of using endophytic-bacteria in the control of M. incognita race 2 in melon.
29
Hýsek, J., J. Kreuzman e J. Brožová. "Reaction of pea selections to Fusarium oxysporum f.sp. pisi (races 1, 2, 5, 6) and Fusarium solani". Plant Protection Science 38, SI 2 - 6th Conf EFPP 2002 (31 dicembre 2017): 561–64. http://dx.doi.org/10.17221/10555-pps.
Abstract (sommario):
Forma specialis (f.sp.) pisi of Fusarium oxysporum infestates pea but on other crop does not cause. Physiological races of this fungus (races 1, 2, 3 and 6) are tested on differentiation selections of pea. In the mixture with Fusarium solani there was better differentiated the reaction of single races. Own method is based on the artificial infection of the pea with the mixture of conidia and mycelial fragments of the race of Fusarium oxysporum f.sp. pisi and Fusarium solani. The roots of germinating pea are partially shortened on the top and poured with the suspension of fungi. After the germinating the infected pea is placed into Perlit (the substance for the cultivation). The pea was watered after that. During 3 years of our work we tested namely many new selections from the breeding station in Lužany. It seems that some of them should be used for new selection of realy resistant varieties. In the year 1999 there were new selection relatively resistant: 595/32, 682/37, 238/847, in the year 2000 no resistant selections were gained and in the year 2001 there were like resistant evaluated these selections: 633/1409 and 1456/1919.
30
Kwon, J. H., O. Choi e J. Kim. "Fusarium oxysporum Causing Wilt and Stem Rot in Chrysanthemum × morifolium in Korea". Plant Disease 97, n. 8 (agosto 2013): 1118. http://dx.doi.org/10.1094/pdis-01-13-0067-pdn.
Abstract (sommario):
The hardy garden mum Chrysanthemum, or “mum” (Chrysanthemum × morifolium Ram.), is a popular flowering herbaceous perennial that is commonly grown for fall sales. In October 2011, suspected wilt disease was observed in potted hardy garden mums (cv. Guiin) grown in greenhouses in Jinju, South Korea. Symptoms included unilateral chlorosis of leaves at the stem apex. Wilted leaves occurred initially on the most severely affected side of the plant, but as the disease progressed, the entire plant wilted and died. Black necrosis and vascular discoloration at the base of stems always developed. Five fungal isolates, successfully isolated from 10 infected stems on potato dextrose agar (PDA), yielded rapidly growing floccose to felt-like colonies, initially white, but turning peach colored. The microconidia were ellipsoid, ovoid, and cylindrical, and measured 3 to 12 × 1 to 3 μm. The macroconidia were falcate, lunate, and measured 8 to 30 × 2 to 4 μm, and had 1 to 5 septa. Pathogenicity was studied in inoculated, potted plants in a greenhouse. A representative isolate of the fungus was grown on PDA at 20°C for about 10 days before inoculation. To obtain conidial suspensions, 10 ml of sterile distilled water (SDW) was added to the culture plates and scraped with a paintbrush to dislodge conidia. The suspension from the culture plates was filtered through cheesecloth and diluted to 2 × 104 micro- and macroconidia/ml with SDW. Nine 3-month-old hardy garden mums were planted in 20-cm-diameter plastic pots containing fine sand. After 10 days, the roots were cut to a depth of 5 cm on two sides of each plant at a distance of 2 cm from the stems. Then, 10 ml of conidial suspension were poured into each pot above the cuts roots, followed by 20 ml 12 days later. Three mums treated with SDW served as controls. Plants were fertilized twice weekly with 100 ml/pot of a nutrient solution (1) that lowered the soil pH and enhanced wilt development. Thirty days after inoculation, all of the artificially inoculated plants had wilted. The control mums remained healthy. The fungus was successfully reisolated to complete Koch's postulates. On the basis of the morphological characters, the fungus was identified as Fusarium oxysporum (3). To identify the isolated fungus, the complete internal transcribe spacer (ITS) rDNA and translation elongation factor 1-alpha (EF1-α) sequences were amplified using the primers ITS1/ITS4 and EF1/EF2, respectively, and sequenced. The resulting sequences were deposited in GenBank (Accession Nos. KC491873 and KC491875). A BLAST search of ITS rDNA (544 bp) and EF1-α (712 bp) sequences against a database of fungal isolates found 100% and 99% similarity to those of F. oxysporum, respectively. Fusarium wilt caused by F. oxysporim on C. morifolium has been previously recorded in North America and India but, to our knowledge, this is the first report of F. oxysporum causing wilt in hardy garden mum in Korea (2). F. oxysporum isolates causing wilts are specific to certain hosts and even to host varieties or cultivars. Further work is required to determine to which forma specialis and race the pathogen belongs. References: (1) A. W. Engelhard and S. S. Woltz. Proc. Fla. State Hort. Soc. 84:351, 1971. (2) H. C. Huang et al. Plant Pathol. Bull. 1:57, 1992. (3) C. V. Subramanian. CMI Descriptions of Pathogenic Fungi and Bacteria. No. 217, 1970.
31
Koike, S. T. "Fusarium Crown and Root Rot of Tarragon in California Caused by Fusarium solani". Plant Disease 95, n. 6 (giugno 2011): 768. http://dx.doi.org/10.1094/pdis-01-11-0058.
Abstract (sommario):
Tarragon, also known as estragon or dragon's-wort (Artemisia dracunculus), is a perennial plant in the Asteraceae. Tarragon is grown for use in cooking as a fresh and dried herb. In May 2010, commercial tarragon grown in a field on California's central coast was affected by a previously undescribed disease. Initial symptoms consisted of chlorosis of leaves and wilting of shoot tips. As the disease progressed, entire shoots and branches turned brown and died. The plant crown epidermis and cortex and the upper cortex of the main roots turned brown with occasional black streaking. Diseased plants died several weeks after the onset of wilting. A Fusarium species was consistently isolated from symptomatic crown and root tissues. On carnation leaf agar (CLA) incubated under lights, the isolates produced stout, slightly curved macroconidia having blunt apical cells. One- and two-celled oval to cylindrical microconidia were abundant and born in false heads on extremely long monophialides. Chlamydospores were present in 1-month-old cultures. On potato dextrose agar incubated under lights, the isolates produced abundant white aerial mycelium with bluish coloration of the culture surface. The isolates were identified as Fusarium solani (2). Pathogenicity tests were conducted using six isolates, with inoculum produced on CLA. For each isolate, 250 ml of a spore suspension (1 × 106 conidia/ml) were poured onto the roots of 10-cm potted tarragon plants. Ten plants were inoculated for each of the six isolates. A control set of tarragon was treated with 250 ml of water. All plants were maintained in a greenhouse set at 24 to 25°C. After 8 weeks, plants inoculated with the spore suspensions began to show wilting and browning of leaves. Crown epidermis and cortex and root cortex tissues were brown; Fusarium solani was reisolated from the crowns and roots. The experiment was repeated and the results were the same. To my knowledge, this is the first report of F. solani causing a crown and root rot disease of tarragon. The disease caused significant damage with approximately 50% of the commercial field affected. The other Fusarium species previously reported on tarragon is an uncharacterized F. oxysporum isolated from roots of plants grown in California (1). References: (1) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ , March 8, 2011, (2) P. E. Nelson et al. Fusarium Species: An Illustrated Manual for Identification. Pennsylvania State University Press, University Park, PA, 1983.
32
Lusiastuti, Angela Mariana, Tuti Sumiati e Adin Priadi. "THE EFFECTS OF STORAGE TEMPERATURE AND TYPES OF MEDIA ON THE SURVIVAL RATE OF S. agalactiae BACTERIOPHAGE". Indonesian Aquaculture Journal 3, n. 2 (31 dicembre 2008): 147. http://dx.doi.org/10.15578/iaj.3.2.2008.147-149.
Abstract (sommario):
The successful effect of phages in phage therapy has been proven by an increase of the presence of phages in survivors. Seven previously isolated phages were used to examine the effects of storage temperature and types of media on their survival rate. Phages PSaT-18, PSaT-19, PSaT-20 and PSaT-21 isolated from a Streptococcosis-infected Tilapia (Oreochromis niloticus) were used in this study. Phages PSaG-1, PSaG-2 and PSaG-3 were isolated from a diseased Gouramy (Osphronemus gouramy). All of the phages were stored in refrigerator at temperature of 8oC and kept in two types of media, Brain Heart Infusion Broth (BHIB) and BHIB enriched with glycerol. To determine the lytic activity of the phages, 20 μL of each phage suspension was poured onto BHIA plate and incubated at 25oC for 24 to 48 hours. The result showed that phages PSaT-18, PSaT-19, PSaT-20 and PSaT-21 have lytic activity against S. agalactiae and S. iniae than phages PSaG-1, PSaG-2, and PSaG-3. Phages PSaT-18, PSaT-19, PSaT-20, and PSaT-21 always survived up to three weeks and phage PSaT-18 in BHIB have the highest potential as a candidate of phage therapy for Streptococcosis.
33
Tragazikis, Ilias K., Alexia N. Koutrakou, Theodoti Z. Kordatou, Panagiota T. Dalla e Theodore E. Matikas. "Monitoring the Nonlinear Acoustic Behavior of Fresh Cementitious Materials during the Hardening Process Using Laser Doppler Vibrometry". Acoustics 2, n. 4 (30 novembre 2020): 833–46. http://dx.doi.org/10.3390/acoustics2040047.
Abstract (sommario):
A challenge in the field of material science and concrete technology is to associate material properties and behavior with changes in internal microstructure. A fundamental issue for planning, implementation, and quality control of construction projects is the fundamental understanding of the hardening process in freshly poured cement-based materials. Shortly after the mixing process, cementitious materials exhibit a substantial damping effect on ultrasonic wave propagation along with low-pulse velocity. The way a wave reflects and diffuses in the volume of a solid material can provide important information about internal heterogeneities. An important application of the wave propagation technique is the determination of layers within the material distinguished by unlike elastic properties. During the hardening process, the ultrasonic wave propagation exhibits a noticeable sensitivity at the point of phase change of the material, that is, the critical point at which the state of the suspension transforms from liquid to solid state. After that point, there is a continuous increase of pulse velocity and ultrasonic signal amplitude. The solidification point is of practical importance since at this point the load-bearing capacity of the composite material and its long-term behavior are based on the connectivity of the solid phase. This study aims to develop a nondestructive tool to monitor freshly poured cement-paste composites at early stages, during the hydration process, by means of nonlinear elastic waves. The measurement setup combined a contact ultrasonic transducer with a noncontact optical detection system, in which the principle of operation is based on the Doppler effect. This methodology enabled us to assess the amplitudes of harmonic vibrations of an acoustic wave propagating through the material with a specific fundamental frequency. This enabled the evaluation of important material properties, such as minute changes in the internal microstructure of fresh concrete during hardening, the evolution of nonlinearity parameters that relate to higher-order elastic constants of the material, as well as the ultrasonic wave velocity.
34
Nakamura, Shingo, Masayuki Ishihara, Yoko Sato, Tomohiro Takayama, Sumiyo Hiruma, Naoko Ando, Koichi Fukuda, Kaoru Murakami e Hidetaka Yokoe. "Concentrated Bioshell Calcium Oxide (BiSCaO) Water Kills Pathogenic Microbes: Characterization and Activity". Molecules 25, n. 13 (30 giugno 2020): 3001. http://dx.doi.org/10.3390/molecules25133001.
Abstract (sommario):
Bioshell calcium oxide (BiSCaO) exhibits deodorizing properties and broad microbicidal activity. In this study, we examined possible utility of BiSCaO Water for that purpose. BiSCaO Water was prepared by adding 10 wt% BiSCaO to clean water and gently collecting the supernatant in a bottle. The same volume of clean water was gently poured onto the BiSCaO precipitate and the supernatant was gently collected in a bottle; this process was repeated fifty times. The produced BiSCaO Water contained nanoparticles (about 400–800 nm) composed of smaller nanoparticles (100–200 nm), and was colorless and transparent, with a pH > 12.7. In vitro assays demonstrated that BiSCaO Water eliminated more than 99.9% of influenza A (H1N1) and Feline calicivirus, Escherichia coli such as NBRC 3972 and O-157:H7, Pseudomonas aeruginosa, Salmonella, and Staphylococcus aureus within 15 min. We compared BiSCaO Water with the other microbicidal reagents such as ethanol, BiSCaO, BiSCa(OH)2 suspensions, povidone iodine, NaClO, BiSCaO dispersion and colloidal dispersion with respect to deodorization activity and microbicidal efficacy. The results showed that BiSCaO Water was a potent reagent with excellent deodorization and disinfection activities against pathogenic bacteria and viruses (including both enveloped and nonenveloped viruses).
35
Papiez, Adriana, Klara Odehnalova, Vladimir Sramek e Pavel Suk. "Comparison of Active Substance Losses and Total Weight Losses of Tablets Administered Via Feeding Tube". Pharmacology 103, n. 5-6 (2019): 246–49. http://dx.doi.org/10.1159/000496423.
Abstract (sommario):
Background/Aims: Administration of tablets via feeding tube (FT) is often associated with significant drug losses, as was confirmed by weighing. The aim of this study was to measure the proportion of active substance losses (ASLs) in an in vitro model. Methods: A film-coated tablet (FilmCT) containing clopidogrel (Trombex®) and a tablet with enteric coating (EntericCT) containing pantoprazole (Controloc®) were crushed in a mortar and transferred by method A (tablet powder was transferred into the beaker, poured into the syringe and water added) and method B (water was added into the mortar, suspension drawn into the syringe) and administered via FT in an in vitro model. Total losses were measured with analytical balance and, simultaneously, ASL were analyzed with high-performance liquid chromatography UV-detection (HPLC-UV). Results: ASL was different to weighing only in the case of EntericCT prepared by method B (2.0 ± 4.2 and 10.7 ± 0.8% for HPLC-UV and weighing, respectively; p = 0.004). HPLC-UV confirmed significantly lower ASL when method B was used for either EntericCT (34.3 ± 7.2 vs. 2.0 ± 4.2%; p < 0.001) or FilmCT (14.1 ± 2.2 vs. 7.7 ± 4.1%; p < 0.01). Conclusion: Drug loss analysis with analytical balance may overestimate ASL, as was proved for EntericCT in this study. ASL were significantly lower when method B was used.
36
Matsunaga, H., T. Sato e S. Monma. "Evaluation of Resistance to Bacterial Wilt and Phytophthora Blight in Peppers (Capsicum spp.) Collected in Ghana and Sri Lanka". HortScience 32, n. 3 (giugno 1997): 450E—451. http://dx.doi.org/10.21273/hortsci.32.3.450e.
Abstract (sommario):
Thirty-one Capsicum accessions collected in Ghana and 20 Capsicum accessions introduced from Sri Lanka were evaluated for resistance to bacterial wilt and to Phytophthora blight. In the evaluation of resistance to bacterial wilt, 12 seedlings per accessions were transplanted to the infected field with Pseudomonas solanacearum. Subsequently, an inoculum suspension was poured into the soil at the base of each plant with root wounding. Disease severity of each plant was evaluated using a symptom index of 0 (no symptoms) to 4 (death) scale at 10 weeks after inoculation. In the evaluation of resistance to Phytophthora blight, 20 seedlings per accession were transplanted into a bed, the soil temperature of which was maintained at 28°C after root-dipping inoculation. Disease severity of each plant was evaluated using a symptom index of 0 (no symptoms) to 2 (death) scale at 2 weeks after inoculation. To bacterial wilt, two Ghanaian accessions and 10 Sri Lankan accessions had no symptoms and nine Ghanaian accessions and six Sri Lankan accessions showed some wilted plants, but their disease indices were less than 1. The accessions were regarded as resistant. To Phytophthora blight, two Ghanaian accessions and four Sri Lankan accessions were regarded as weakly resistant. Remaining accessions were regarded as susceptible. `GJ93/287' collected in Ghana and `Nil miris', `MI 1', `KA 11', introduced from Sri Lanka, were resistant to bacterial wilt and weakly resistant to Phytophthora blight.
37
Royan, R. Nishata, Abu Bakar Sulong e Jaafar Sahari. "Effect of Loading Concentration on the Electrical and Hardness Properties of MWCNT/Epoxy Nanocomposites". Key Engineering Materials 471-472 (febbraio 2011): 157–61. http://dx.doi.org/10.4028/www.scientific.net/kem.471-472.157.
Abstract (sommario):
Carbon nanotubes have excellent mechanical and electrical properties, and are also a good reinforcement material for composites than conventional materials. The matrix used in this study was epoxy and reinforcement filler in multi-walled carbon nanotubes (MWCNTs). The different MWCNTs loading concentrations (0 ~ 10 wt. %) were added into the epoxy resin. The dispersion of MWCNTs in epoxy resin was conducted using high speed mixer through mechanical shearing mechanism. The mixture of epoxy/MWNTs suspension was poured into the mold and compression molding was conducted for fabrication of MWCNTs/epoxy nanocomposites. The electrical conductivity of nanocomposite by variation of CNTs concentration was measured by the four point probe. Dispersion state of CNTs in epoxy matrix was observed on fractured surface by scanning electron microscopic. Hardness of the composite was tested using the Dinamic Ultra Micro Hardness machine. Non conductive epoxy polymer becomes conductor as addition of CNTs.. Electrical conductivity of nanocomposite plates increased with increasing CNTs concentration. Agglomerations of CNTs were observed on fractured surfaces. This phenomenon due to CNTs which used in this study was at as produced state where no modification is being done on it. Long and entanglement of individual CNTs easily lead to agglomerations. Van de Wall’s force interactions between CNTs also contribute to the agglomerations of CNTs. Hardness of the composite increases with the CNTs loading concentrations until it reaches a maximum peak at the composition of 5wt% of CNTs but the hardness decreases rapidly with loading greater than 5wt% of CNTs.
38
Raza, Ali, Umair Khan, Aurang Zaib, Wajaree Weera e Ahmed M. Galal. "A comparative study for fractional simulations of Casson nanofluid flow with sinusoidal and slipping boundary conditions via a fractional approach". AIMS Mathematics 7, n. 11 (2022): 19954–74. http://dx.doi.org/10.3934/math.20221092.
Abstract (sommario):
<abstract> <p>This paper addresses a mixed and free convective Casson nanofluid flowing on an oscillating inclined poured plate with sinusoidal heat transfers and slip boundaries. As base fluid water is supposed and the suspension of nanofluid is formulated with the combination of individual copper $ \left(Cu\right) $, titanium dioxide $ \left(Ti{O}_{2}\right) $ and aluminum oxide $ \left(A{l}_{2}{O}_{3}\right) $ as nanoparticles, the dimensionless governing equations are generalized based on Atangana-Baleanu (AB) and Caputo-Fabrizio (CF) fractional operators for developing a fractional form. Then, for the semi-analytical solution of the momentum and thermal profiles, the Laplace transformation is utilized. To discuss the influences of various pertinent parameters on governing equations, graphical tablecomparison of the Nusselt number and skin friction is also inspected at different times and numerical schemes. As a result, it has been concluded that both the momentum and energy profiles represent the more significant results for the AB-fractional model as related to the CF-fractional model solution. Furthermore, water-based titanium dioxide $ \left(Ti{O}_{2}\right) $ has a more progressive impact on the momentum as well as the thermal fields as compared to copper $ \left(Cu\right) $ and aluminum oxide $ \left(A{l}_{2}{O}_{3}\right) $ nanoparticles. The Casson fluid parameter represents the dual behavior for the momentum profile, initially momentum field decreases due to the Casson parameter but it then reverses its impact and the fluid flow moves more progressively.</p> </abstract>
39
Eriani, Kartini, Irma Suryani, Al Azhar, Risa Nursanti, Ichsan Ichsan e Arief Boediono. "Neurogenic Differentiation of Bone Marrow Mesenchymal-Like Stem Cell Induced by Delonix regia Flowers Extract". Biosaintifika: Journal of Biology & Biology Education 10, n. 2 (29 agosto 2018): 417–23. http://dx.doi.org/10.15294/biosaintifika.v10i2.15051.
Abstract (sommario):
Stem cell technology has great potential in the effort to cure degenerative diseases. This study was done to determine optimum dose of flamboyant (Delonix regia) flower extract to induce proliferation and differentiation of mice (Mus musculus) bone marrow mesenchymal-like stem cell. Bone marrow cells were collected from mice by aspiration. Cells suspension (1 x 106) were poured into petri dishes containing 2 ml of modified Dulbecco's Modified Eagle's Media (mDMEM) and incubated overnight at 37 °C in a 5% CO2 incubator and microscopically observed. In quadriplicate, MSC were cultured in mDMEM containing D. regia flower extract of 0.0 (control), 0.4, 0.6, 0.8, and 1.0 mg/ml and incubated at 37 °C for 9 days. Population doubling time (PDT) and differentiated cell type were microscopically observed using HE staining on day 1 and 10. Data obtained were analyzed by ANOVA and Tukey test. The results showed that the addition of D regia flowers extracts 0.8 and 1.0 mg/ml significantly reduced PDT compared to that of 0.4, 0.6 and control. The extract, at 0.4 and 0.6 mg/ml, were able to induce MSC differentiation into fibroblast-like and nerve-like cells. In conclusion, D. regia flower extracts of 0.6, 0.8 and 1.0 mg/ml were able to stimulate MSC proliferation, but optimum dose for neurogenic differentiation was 0.6 mg/ml. This is the first to show potential of D. regia flower extract as neurogenic differentiatian inducer on mice MSC. These findings can be used as preliminary information for using the extract as cellular differentian inducer in basic and applicative reseach using stem cells.
40
Awlachew, Zewdu Teshome, e Gebeyehu Yibeltie Mengistie. "Growth Promotion of Rice (Oryza sativa L.) Seedlings Using Plant Growth-Promoting Rhizobacteria (PGPR) Isolated from Northwest Ethiopia". Advances in Agriculture 2022 (26 ottobre 2022): 1–8. http://dx.doi.org/10.1155/2022/1710737.
Abstract (sommario):
Plant growth-promoting rhizobacteria (PGPR) are beneficial soil microorganisms that colonize plant roots and enhance plant growth by a wide variety of mechanisms. In this work, five Bacillus and two Cyanobacteria isolates were successfully isolated and characterized. A pot experiment was conducted to evaluate the effect of PGPR on the growth of three cultivars of rice seedlings. Pots were laid down in a complete random design and 100 ml of spore and Cyanobacteria suspension were poured on the soil surface surrounding each seedling. After 45 days, the seedlings were uprooted and shoot and root parameters were recorded. All the Bacillus and Cyanobacteria isolates showed positive effects on the growth of rice seedlings as compared to control; however, their effectiveness varies from isolate to isolate and also from cultivar to cultivar. Bacterial isolates B3 and B5 showed the highest mean value and statistically significant difference ( P < 0.05 ) in most of the root and shoot parameters of cultivars Jegna and Getachew, respectively, as compared to other bacterial isolates. Both cyanobacterial isolates showed the highest and statistically significant difference ( P < 0.01 ) in almost all the above ground and underground growth parameters compared to other bacterial isolates in all the three cultivars of rice. Similarly, C2 and C1 recorded the highest growth promotion efficacy of shoot and root length (50.07% and 78.27%) on Edget and Getachew cultivars, respectively. Hence, the present study suggests that the use of PGPR isolates such as B3, B5, C1, and C2 as inoculant biofertilizers might be beneficial for rice cultivation as they enhanced the growth of rice seedlings.
41
Dutra, Mateus José. "Analysis of the Antimicrobial Efficacy, In Vitro, of Oral Antiseptics on Fungi and Bacteria". Open Access Journal of Dental and Oral Surgery (OAJDOS) 2, n. 2 (22 luglio 2021): 1–6. http://dx.doi.org/10.54026/oajdos/1019.
Abstract (sommario):
Objectives: The study aimed to evaluate the action, in vitro, of hydrogen peroxide in the concentrations of 1%, 1.5% and 3%, of cetylpyridinium chloride, of benzalkonium chloride of 1.3% and of chlorhexidine 0.12% associated with 1.5% hydrogen peroxide over standardized strains of microorganisms Enterococcus faecalis; Staphylococcus aureus; Candida albicans and Escherichia coli, aspiring to determine which is the best product. Chlorhexidine 0.12% was used as a positive control and sterile distilled water as a negative control. Methodology: Standardized suspensions of the microorganisms were prepared, poured and spread over the culture media. Sterile 4 mm paper discs were placed on the seeded agar and soaked with 15 microliters (uL) of each of the antiseptics. The plates were incubated in a bacteriological oven at 37º Celsius for 48 hours. The results were obtained through the growth inhibition halo. Results: The antiseptic that obtained the greatest antimicrobial action was the association of hydrogen peroxide at 1.5% with chlorhexidine at 0.12%, followed by benzalkonium chloride 1.3%. Hydrogen peroxide at 1% did not show any antimicrobial activity. Conclusions: The 0.12% chlorhexidine associated with 1.5% hydrogen peroxide demonstrated the best antimicrobial action, indicating a possible synergistic action between the products, increasing the efficiency when compared to the isolated use of each active ingredient. Benzalkonium chloride 1.3%, also showed an effective antimicrobial action, indicating that these products or combinations have a great potential to be used as an active ingredient in mouthwashes.
42
Bhat, Fasil Ahmad. "To Study the Partial Replacement of Cement with Bamboo Leaf Ash and Addition of Glass Fiber". International Journal for Research in Applied Science and Engineering Technology 11, n. 12 (31 dicembre 2023): 2080–87. http://dx.doi.org/10.22214/ijraset.2023.57733.
Abstract (sommario):
Abstract: Concrete could be a material which is a mixture of coarse and fine mixture bonded along with a fluid cement (cement paste) that hardens or cures over time. Once aggregate is mixed with cement & water, the mixture forms a fluid suspension that's simply poured and formed into shape. The cement reacts with the water and different constituents to create a tough matrix that binds all the materials along into a stone-like material that has several uses. Reinforcement material used should have excellent bonding characteristic, high tensile strength and good thermal compatibility. Reinforcement requires that there shall be smooth transmission of load from the concrete to the interface between concrete and reinforcement material and then on to reinforcement material. . Glass fiber-reinforced concrete premix is a mixture of AR glass fiber, sand, cement, water, chemical and mineral admixtures, and aggregate. These fibers reduce crack width and spacing between cracks. They are very high temperature resistant as they absorb high energy thereby providing the property of ductility the content of bamboo ash is constituted of inorganic minerals, which consists mainly silica, potassium and calcium. Magnesium and manganese are other two common minerals. The result shows that concrete workability is fine and within limits after replacing cement with BLA with adding glass fibers. However, workability gets reduced at higher replacement of materials. The strength parameters such as compressive strength, flexural strength, and split tensile strength also increase and show an optimum value at 12% cement replacement and 1.5% Addition of glass fibers respectively. Test results are satisfactory up to 12% and 1.5% replacement. After this, there is a decrease in the strength of concrete.
43
Thaweboon, Sroisiri, Passiri Nisalak, Boonyanit Thaweboon, Pornrachanee Sawaengkit, Plang Ngern Saksit e Rattiporn Kaypetch. "Antimicrobial Activity of Type III Dental Gypsum Incorporated with 3-iodo-2-propynyl-butylcarbamate and its Physical Properties". Advanced Materials Research 1052 (ottobre 2014): 322–26. http://dx.doi.org/10.4028/www.scientific.net/amr.1052.322.
Abstract (sommario):
Dental impressions have been considered to be potential sources of microbial contamination from patients’ blood and saliva to dental personnel and prostheses fabricated on gypsum casts. Thus, the development of dental gypsum with antimicrobial activity to reduce cross-contamination between patients and laboratory personnel is needed. This study aims to evaluate the influence of incorporation of 3-iodo-2-propynyl-butylcarbamate (IPBC) into type III dental gypsum on its antimicrobial activities and physical properties such as dry compressive strength and setting time. Type III dental gypsum (The Siam Moulding Plaster Co., Ltd, Thailand) incorporated with 3 concentrations of IPBC (0.01%, 0.005% and 0.001% w/w) was tested compared with the control, gypsum without disinfectant. Microorganisms tested were Staphylococcus aureus ATCC 6538, Pseudomonas aeruginosa ATCC 27853 and Candida albicans ATCC 1023. One hundred μL of each microbial suspension (108 CFU/mL) was dropped on hydrocolloid impression (Jeltrate; Caulk/Dentsply, Milford, DE) and left dry. All types of gypsum mixes were prepared and poured into the impressions and allowed to set for 60 min. Then the gypsum samples were removed and the microbial contact surfaces were imprinted on Brain Heart Infusion agar plates. After incubation, colonies appeared on agar were gram-stained and counted. The dry compressive strength and setting time were tested in accordance with International Standard (ISO) 6873: 1998 (E). Dental gypsum containing IPBC showed antimicrobial activity against all tested microorganisms with the percentage of microbial reduction ranging from 19.4% to 70.6%. Among all types of dental gypsum, no significant differences in dry compressive strength and setting time were observed. The newly developed type III dental gypsum incorporated with IPBC had antimicrobial effects against all tested microorganisms. The physical properties of the modified dental gypsum were within the ISO standards. However, further investigation on other properties such as dimensional stability, detail reproduction and clinical usage are still needed.
44
Ushida, Takashi, Katsuko Furukawa, Kenshi Toita e Tetsuya Tateishi. "Three-Dimensional Seeding of Chondrocytes Encapsulated in Collagen Gel into PLLA Scaffolds". Cell Transplantation 11, n. 5 (luglio 2002): 489–94. http://dx.doi.org/10.3727/000000002783985611.
Abstract (sommario):
Tissue engineering approaches have been clinically tried to repair damaged articular cartilages. It is an essential step to uniformly seed chondrocytes into 3D scaffolds in order to reconstruct tissue-engineered cartilages in vitro, but the tissue engineering could not have been provided with efficient cell seeding methods. Type I collagen is clinically used and known as a cytocompatible material, having recognition sites for integrins. Collagen gel encapsulating chondrocytes has been tried for making regenerated cartilages, but it is found difficult to have the gel keep its original shape after long-term culture, because of shrinking. On the other hand, 3D scaffolds, either of a nonwoven structure or a sponge-like structure, involve difficulty in that chondrocytes could not be uniformly seeded, although they have adequate initial mechanical properties. In this study, by combining collagen gelation with a nonwoven PLLA scaffold, we achieved uniform cell seeding into the 3D scaffold. Bovine articular chondrocytes were mixed with type I collagen solution, and the solution was poured into the nonwoven PLLA scaffold (1.5 mm thick, f 15 mm). The collagen–chondrocyte mixture was made into gel at 37°C for 1 h. The 0.39% collagen mixture was viscous enough to prevent cells from precipitating during gelation. Almost all chondrocytes were able to be incorporated into the PLLA scaffolds by mixing with collagen solution and subsequently making into gel, while 30–40% of the chondrocytes seeded as a cell suspension were not trapped into the PLLA scaffolds. The method presented, where chondrocytes were mixed with collagen solution, and the mixture was incorporated into a 3D scaffold, then made into gel in the scaffold, could serve as an alternative for in vitro cartilage regeneration, also simultaneously having the advantages of both materials.
45
Stepanov, M. S., A. P. Godovalov, E. E. Kobzarenko, M. V. Fadeeva e E. A. Gyr. "A new approach for the study of the morphological structure of microbal biofilms". Russian Clinical Laboratory Diagnostics 65, n. 10 (17 settembre 2020): 649–51. http://dx.doi.org/10.18821/0869-2084-2020-65-10-649-651.
Abstract (sommario):
Microbial biofilms are heterogeneous, moving and constantly changing communities of microorganisms, often of various taxons. Approaches to study and assessment anti-biofilm drugs widely available today do not adequately assess their effects, while the results of studying the interaction of drugs with components of the film composition can provide them the right choice. The aim of investigation was to test a new method of morphological evaluation of biofilms. To form biofilms, we used an approach when the slide was placed at an angle of 30o-45o relatively to the Petri dish, and a suspension of test strains S. epidermidis in peptone broth was poured into the space between the Petri dish and the slide. A sterile cotton swab moistened with distilled water was placed next to the glass slide to create optimal humidity. The system was placed in a thermostat for 24 hours. The formed films were examined under a microscope using the DCM 310 video eyepiece and the Scope photo x86,3.1.312 program that allowed to conduct a complete morphometric study of the film: select layers, channels, cavities and make measurements, and then save the results on electronic media in jpg file format. Microscopy of the stained slides revealed that the biofilm has a layered structure. In each image obtained using a video eyepiece, it was possible to differentiate 4 layers. From the border of the two media to the inside: the fragmentation layer, the dense layer, the matrix substance layer, and the last one - the persistence layer. Channels of different diameters (from 10 to 24 microns) are observed across the entire thickness of the biofilm. Thus, used approach allows us to visualize and evaluate the structure of microbial biofilm, measure the thickness of layers and channel diameters. In addition, this method can be used to study the effect of antimicrobial drugs on bacterial films.
46
Mansoor, Afsheen, Zohaib Khurshid, Emaan Mansoor, Muhammad Talal Khan, Jithendra Ratnayake e Asif Jamal. "Effect of Currently Available Nanoparticle Synthesis Routes on Their Biocompatibility with Fibroblast Cell Lines". Molecules 27, n. 20 (17 ottobre 2022): 6972. http://dx.doi.org/10.3390/molecules27206972.
Abstract (sommario):
Nanotechnology has acquired significance in dental applications, but its safety regarding human health is still questionable due to the chemicals utilized during various synthesis procedures. Titanium nanoparticles were produced by three novel routes, including Bacillus subtilis, Cassia fistula and hydrothermal heating, and then characterized for shape, phase state, size, surface roughness, elemental composition, texture and morphology by SEM, TEM, XRD, AFM, DRS, DLS and FTIR. These novel titanium nanoparticles were tested for cytotoxicity through the MTT assay. L929 mouse fibroblast cells were used to test the cytotoxicity of the prepared titanium nanoparticles. Cell suspension of 10% DMEM with 1 × 104 cells was seeded in a 96-well plate and incubated. Titanium nanoparticles were used in a 1 mg/mL concentration. Control (water) and titanium nanoparticles stock solutions were prepared with 28 microliters of MTT dye and poured into each well, incubated at 37 °C for 2 h. Readings were recorded on day 1, day 15, day 31, day 41 and day 51. The results concluded that titanium nanoparticles produced by Bacillus subtilis remained non-cytotoxic because cell viability was >90%. Titanium nanoparticles produced by Cassia fistula revealed mild cytotoxicity on day 1, day 15 and day 31 because cell viability was 60–90%, while moderate cytotoxicity was found at day 41 and day 51, as cell viability was 30–60%. Titanium nanoparticles produced by hydrothermal heating depicted mild cytotoxicity on day 1 and day 15; moderate cytotoxicity on day 31; and severe cytotoxicity on day 41 and day 51 because cell viability was less than 30% (p < 0.001). The current study concluded that novel titanium nanoparticles prepared by Bacillus subtilis were the safest, more sustainable and most biocompatible for future restorative nano-dentistry purposes.
47
YOUSEF, AHMED E., e ELMER H. MARTH. "Quantitation of Growth of Mold on Cheese". Journal of Food Protection 50, n. 4 (1 aprile 1987): 337–41. http://dx.doi.org/10.4315/0362-028x-50.4.337.
Abstract (sommario):
Earlier work by others indicated that a mold colony grows radially at a constant rate on solid media. This concept was used in our study to develop a method for quantifying growth of mold on cheese. The ability of molds to grow on cheeses or pasteurized process cheese made with or without addition of sorbate was compared. Cheeses tested were mild Cheddar, aged Cheddar, aged-smoked Cheddar, brick and pasteurized process cheese. Pasteurized process cheeses were made from the natural cheeses by addition of water and a phosphate salt, then the mixture was heated. Some pasteurized process cheese from mild Cheddar was made to contain 0–500 ppm sorbic acid. Natural cheeses were sliced under aseptic conditions and were placed in sterile petri-plates. The hot and molten pasteurized process cheeses were poured into petri-plates. A spore suspension of Aspergillus parasiticus or Penicillium camemberti was inoculated onto the center of the cheese slice or pasteurized process cheese, and plates were covered and incubated at 22°C. The radius of mold colonies was measured at 24-h intervals. Data were analyzed by linear regression and lag period and rate of radial growth were calculated. Mold colonies grew radially at constant rates on cheeses and pasteurized process cheese. Lag in growth of each mold was longest on aged Cheddar cheese and pasteurized process cheese made from it, whereas it was shortest on mild Cheddar, brick and pasteurized process cheeses made therefrom. A. parasiticus grew faster on all cheeses and pasteurized process cheeses than did P. camemberti. Aged Cheddar cheese and pasteurized process cheese made from it effectively slowed the growth of both molds that were studied. Pasteurized process cheese containing sorbic acid inhibited growth of both molds. Generally, the higher the concentration of sorbic acid in the pasteurized process cheese, the slower was mold growth and the longer was the lag period.
48
Khetagurov, Valery, Evgeny Kamenetsky, Mikhail Gegelashvili e Azamat Marzoev. "Granulometric composition study of fine product obtained by dolomite grinding in a centrifugal mill of vertical type". Sustainable Development of Mountain Territories 16, n. 1 (30 marzo 2024): 197–204. http://dx.doi.org/10.21177/1998-4502-2024-16-1-197-204.
Abstract (sommario):
Introduction. Modern medium (10–200 microns) and fine (0.1–10.0 microns) powders have a high cost, which limits the scale of their production and use. This assumes the implementation the latest achievements in the field of creating new equipment that is not inferior in its technical characteristics to the best foreign models into industry. The use centrifugal mills of vertical type for grinding various raw materials has shown their high efficiency in obtaining materials in the range – 0.2–0.01 mm. Studies of these mills operation under various operating conditions made it possible to create a large data set on the dependence of the crushed material granulo-metric composition on the design features of the mills and technological parameters of the grinding process. The results of a previously study of the granulo-metric composition a finely dispersed crushed product integral distribution according to particle size classes less than 80 microns were presented. They were obtained in a Brookhaven BI-XDC X-ray analytical centrifuge by measuring particle sizes in natural sedimentation mode, when the centrifuge disk was stationary during the experiment. The studies of the particle size differential distribution of a finely dispersed crushed product according to particle size classes less than 80 microns, which have not been carried out to date are of particular interest. Purpose of the study. The differential distribution study of the finely dispersed granulo-metric product composition obtained by grinding lump dolomite in a centrifugal mills of vertical type under different operating modes. Materials and methods. To solve this problem, samples of crushed material were taken from grinding dolomite from the Bosninsky deposit (RNO-Alania) in a centrifugal mill of the vertical type MV-0.3 with a 300 mm rotor diameter with following technological modes of the grinding process: mill rotor speed n = 310; 360 min–1, height of the material column above the rotating rotor H = 180; 270 mm, test time – 6 hours. Selected samples with a size class of –0.08 mm were analyzed in an X-ray analytical centrifuge Brookhaven BI-XDC, designed to determine the particle size distribution in the range from 0.01 to 100 microns. The measurements were performed on a suspension prepared from a mixture of 0.5 g of the selected sample with a 20% solution of sucrose and distilled water. Samples with a size class of 0.08 mm were weighed on laboratory scales LV SP.005.048 RE. The resulting suspension was dispersed in an ultrasonic bath for 3–5 minutes. After dispersion, the suspension was poured into the analyzer disk. While stirring, the lower absorption baseline line of a homogeneous particle suspension was measured. The obtained data from the analysis of the fine fractions size of were processed by the centrifuge computer software and graphs of the differential distribution of particles were constructed for various technological modes of grinding dolomite in a centrifugal mill. During the processing of the experiments, minor bursts in the concentration of the crushed product were not taken into account. The results and discussion. For the first time, a differential analysis of the granulo-metric composition of finely dispersed material with a particle size of –0.08 mm, obtained by grinding lump dolomite in a centrifugal mill of the vertical type under different mill operating modes, was carried out. Under all investigated operating modes of the centrifugal mill, the main part of the fine fraction in the mill outlet was in the range from 1.197 to 4.643 μm, and in steady-state operation it varied from 1.310 to 4.601 μm. The range of fine particle sizes has maximum values when the height of the column of crushed material above the rotating mill rotor and the rotation speed of the mill rotor decrease, and minimum values are observed when the height of the column of crushed material above the rotating mill rotor increases and the rotation speed of the mill rotor increases. Resume. 1. The article presents the results of the granulo-metric composition differential distribution study of a finely dispersed product obtained by grinding lump dolomite in a centrifugal mill of the vertical type. 2. The conducted studies have shown that, despite the positive results in obtaining fine particles with a size of 0.001 microns (nanoparticles) by mechanical means, the industrial production of nano-materials when grinding lump mineral raw materials in a vertical centrifugal mill is not economically profitable due to the low specific productivity and high energy intensity of the grinding process. 3. The obtained research results can be useful in the design of centrifugal mills.
49
Thaweboon, Sroisiri, Boonyanit Thaweboon, Plang Ngern Saksit, Passiri Nisalak e Rattiporn Kaypetch. "Type IV Dental Stone Incorporated with Antimicrobial Agents and its Physical Properties". Advanced Materials Research 898 (febbraio 2014): 292–95. http://dx.doi.org/10.4028/www.scientific.net/amr.898.292.
Abstract (sommario):
Contamination of dental casts can occur via direct contact with impression materials that are contaminated by patients fluids. Thus, the development of dental stone with antimicrobial activity to reduce cross-contamination between patients and laboratory personnel is needed. This study aims to evaluate the influence of incorporation of disinfectants into type IV dental stone on its antimicrobial activities and physical properties such as setting time and dry compressive strength. Type IV dental stone incorporated with 4 types of disinfectants; Diamond Rock D (3-iodo-2-propynylbutylcarbamate), Diamond Rock B (zeolite), Diamond Rock Z (thiabendazole) and Diamond Rock T (2-benzimidazole carbamic acid), were tested in this study compared with the control, Diamond Rock O (type IV dental stone without disinfectant). Microorganisms tested wereStaphylococcus aureusATCC 6538,Pseudomonas aeruginosaATCC 27853 andCandida albicansATCC 1023. One hundred μL of each microbial suspension (108CFU/mL) was dropped on hydrocolloid impression (Jeltrate; Caulk/Dentsply, Milford, DE) and left dry. All types of stone mixes were prepared and poured into the impressions and allowed to set for 60 min. Then the stone samples were removed and the microbial contact surfaces were imprinted on Brain Heart Infusion agar plates. After incubation, colonies appeared on agar were gram-stained and counted. The setting time and dry compressive strength were tested in accordance with International Standard (ISO) 6873: 1998 (E). Dental stone incorporated with 4 types of disinfectants showed antimicrobial activity against all tested microorganisms with the percentage of microbial reduction ranging from 83% to 100%. Among all types of dental stone, no significant difference in setting time was observed. In dry compressive strength testing, the disinfectant-containing dental stone had significant higher strength than that without the disinfectant. The newly developed type IV dental stone incorporated with disinfectants had antimicrobial effects against all tested microorganisms. The physical properties of the modified dental stones were within the ISO standards. However, further investigation on other properties such as dimensional stability, detail reproduction and clinical usage are still needed.
50
Tymoszuk, Alicja, e Jacek Wojnarowicz. "Zinc Oxide and Zinc Oxide Nanoparticles Impact on In Vitro Germination and Seedling Growth in Allium cepa L." Materials 13, n. 12 (19 giugno 2020): 2784. http://dx.doi.org/10.3390/ma13122784.
Abstract (sommario):
Zinc oxide nanoparticles (ZnO NPs) are ones of the most commonly manufactured nanomaterials worldwide. They can be used as a zinc fertilizer in agriculture to enhance yielding and to control the occurrence of diseases thanks to its broad antifungal and antibacterial action. The aim of this study was to investigate and compare the effects of ZnO submicron particles (ZnO SMPs) and ZnO NPs on the process of in vitro seed germination and seedling growth in onion (Allium cepa L. ‘Sochaczewska’), and to indicate the potential use of these compounds in onion production. In the experiment, disinfected seeds were inoculated on the modified Murashige and Skoog (MS) medium and poured with ZnO SMP or ZnO NP water suspension, at the concentrations of 50, 100, 200, 400, 800, 1600, and 3200 mg∙L−1. During three successive weeks, the germinating seeds were counted. Germination started most often on the second or third day of in vitro culture. The highest share of germination was recorded for seeds treated with 800 mg∙L−1 ZnO SMPs and ZnO NPs (52% and 56%, respectively). After the application of ZnO SMPs and ZnO NPs at the highest tested concentration (3200 mg∙L−1), the share of germinating seeds was only 19% and 11%, respectively. Interestingly, seedlings obtained from control seeds and seeds treated with ZnO SMPs and ZnO NPs did not differ statistically in terms of length, fresh weight, and dry weight of leaves, and roots. Both ZnO SMPs and ZnO NPs, in the concentration range from 50 to 1600 mg∙L−1, can be used to stimulate the germination process of onion seeds, without negative effects on the further growth and development of seedlings. There were no differences found between the action of ZnO NPs and ZnO SMPs, which suggested that the most important factor influencing seed germination was in fact the concentration of zinc ions, not the particle size.