128 research outputs found
Dynamic growth effects during low-pressure deposition of diamond films
Diamond films were deposited in a modified electronâcyclotron-resonance plasma system operating at pressures between 1.0 and 2.0 Torr. This system provides the advantage of efficient plasma generation due to magnetic enhancement and high diffusion rates due to relatively low-pressure operation. Films were formed from preexisting seed layers providing high ânucleationâ densities to promote rapid coalescence. Raman analysis of grown films showed a quality dependence on both deposition pressure and nucleation density. We speculate that the increased presence of amorphous carbon and larger film stresses is the result of grain-boundary impurity effects in the seeded films. Oxygen addition improved film quality by reducing nondiamond carbon incorporation. © 1997 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69661/2/APPLAB-70-15-1974-1.pd
Second order Raman spectroscopy of the wurtzite form of GaN
We report on Raman scattering by phonon pairs in GaN films grown on sapphire substrates by plasmaâenhanced molecular beam epitaxy. The first order data are consistent with results obtained from GaN bulk crystals of the wurtzite structure. The A1 and the much weaker E2 symmetry components of the second order scattering have been identified. Twoâphonon spectra are dominated by contributions due to longitudinal optical phonons. © 1995 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70248/2/JAPIAU-77-11-6042-1.pd
Microwave dielectric relaxation & polarization study of binary mixture of methylethylketone with nitrobenzene
Present paper reveals detailed study of dielectric relaxation and dielectric polarization and physicochemical study of binary polar-polar liquid mixture i.e. dielectric constant, relaxation time, viscosity, density of methylethylketone (MEK) with nitrobenzene (NB) at 303 K. The measured dielectric and physicochemical parameters employed to acquire additional derived properties like Bruggeman factor, molar refraction and excess properties like static dielectric constant, excess inverse relaxation time, excess molar volume, excess viscosity, excess molar refraction, Gibbs free energy, and enthalpy of activation. The variation of this parameters with composition of these quantities has been used to explain the type, strength and nature of intermolecular interactions between MEK+NB binary mixture. Attained results authenticate that there are strong hydrogen-bond interactions between unlike molecules of different groups of MEK+NB mixtures and that 1:1 complexes are produced and strength of intermolecular interaction rises with rise in concentration of MEK.               KEY WORDS: Bruggeman factor, Excess inverse relaxation time, Dielectric polarization Bull. Chem. Soc. Ethiop. 2019, 33(2), 349-358.DOI: https://dx.doi.org/10.4314/bcse.v33i2.1
Experimental inoculation of a crow derived influenza A (H5N1) virus in chickens and its pathological and genetic characterization
We report the infectivity of a crow derived influenza A (H5N1) virus (A/crow/India/01TR01/2012) in chickens and its pathological and genetic characterization. Histopathological changes and immunohistochemistry staining of internal organs and skeletal muscle were consistent with influenza A virus infection. Real time RT-PCR and virus isolation results demonstrated the systemic spread of the virus in chickens with 100% mortality. Comparatively higher level of virus shedding was detected in oropharyngeal swab (7.63Ă106 viral RNA copy) than in cloacal swab (6.66 Ă 106 viral RNA copy). Concentrations of viral antigen in kidney, lungs, brain, spleen and large intestine were higher compared to pancreas and skeletal muscle. No genetic change was observed on interspecies transmission of the virus. The study revealed that the crow derived H5N1 virus is able to kill the poultry, underlining the need for close monitoring of presence of virus in poultry near crow roosting areas so that further transmission to other avian and mammalian hosts can be prevented
Dietary Supplementation with Soluble Plantain Non-Starch Polysaccharides Inhibits Intestinal Invasion of Salmonella Typhimurium in the Chicken
Soluble fibres (non-starch polysaccharides, NSP) from edible plants but particularly plantain banana (Musa spp.), have been shown in vitro and ex vivo to prevent various enteric pathogens from adhering to, or translocating across, the human intestinal epithelium, a property that we have termed contrabiotic. Here we report that dietary plantain fibre prevents invasion of the chicken intestinal mucosa by Salmonella. In vivo experiments were performed with chicks fed from hatch on a pellet diet containing soluble plantain NSP (0 to 200 mg/d) and orally infected with S.Typhimurium 4/74 at 8 d of age. Birds were sacrificed 3, 6 and 10 d post-infection. Bacteria were enumerated from liver, spleen and caecal contents. In vitro studies were performed using chicken caecal crypts and porcine intestinal epithelial cells infected with Salmonella enterica serovars following pre-treatment separately with soluble plantain NSP and acidic or neutral polysaccharide fractions of plantain NSP, each compared with saline vehicle. Bacterial adherence and invasion were assessed by gentamicin protection assay. In vivo dietary supplementation with plantain NSP 50 mg/d reduced invasion by S.Typhimurium, as reflected by viable bacterial counts from splenic tissue, by 98.9% (95% CI, 98.1â99.7; P<0.0001). In vitro studies confirmed that plantain NSP (5â10 mg/ml) inhibited adhesion of S.Typhimurium 4/74 to a porcine epithelial cell-line (73% mean inhibition (95% CI, 64â81); P<0.001) and to primary chick caecal crypts (82% mean inhibition (95% CI, 75â90); P<0.001). Adherence inhibition was shown to be mediated via an effect on the epithelial cells and Ussing chamber experiments with ex-vivo human ileal mucosa showed that this effect was associated with increased short circuit current but no change in electrical resistance. The inhibitory activity of plantain NSP lay mainly within the acidic/pectic (homogalacturonan-rich) component. Supplementation of chick feed with plantain NSP was well tolerated and shows promise as a simple approach for reducing invasive salmonellosis
Physicochemical and textural quality attributes of gluten-free bread formulated with guar gum
The objective of this study was to assess the combined effect of guar gum (GG) and water content (WC) on the rheological properties of batter, and the physicochemical and textural properties of bread. Batches of gluten-free bread used a base formulation of rice (50%), maize (30%) and quinoa flour (20%), with different levels of GG (2.5, 3.0 or 3.5%) and water (90, 100 or 110%) in a full factorial design. Higher GG doses (p<0.001) tended to produce batters of lower stickiness, work of adhesion and cohesive strength; yet, of higher firmness, consistency, cohesiveness and viscosity index. These batters yielded loaves of lower (p<0.001) specific volume and baking loss; and crumbs of lower (p<0.001) aw, pH, mean cell area, void fraction, mean cell aspect ratio; and higher (p<0.001) hardness, adhesiveness, springiness, cohesiveness, chewiness, resilience, mean cell density, cell size uniformity and mean cell compactness. The sticker and less consistent batters produced with higher WC rendered larger bread loaves of softer and more cohesive and springy/resilient crumbs with greater mean cell size and void fraction. Gluten-free loaves of good appearance in terms of higher specific volume, lower crumb hardness, higher crumb springiness, and open grain visual texture were obtained in formulations with 110% WC and GG doses between 2.5 and 3.0%.Eng. Encina-Zelada acknowledges the financial aid provided by the Peruvian National Programme of Scholarships and Student Loans (PRONABEC) in the mode of PhD grants (Presidente de la RepĂșblica-183308). The authors are grateful to Eng. Andrea Oliveira from Prodipani, Portugal, for her kind advice and providing breadmaking ingredients.info:eu-repo/semantics/publishedVersio
Phenolic, polysaccharidic and lipidic fractions of mushrooms from northeast Portugal: chemical compounds with antioxidant properties
Mushrooms do not constitute a significant portion of the human diet, but their consumption continues to increase due to their functional benefits and presence of bioactive compounds. Some of those compounds can be found in the phenolic, polysaccharidic and lipidic fractions of edible and inedible species. Herein, those fractions of five wild mushrooms (Coprinopsis atramentaria, Lactarius bertillonii, Lactarius vellereus, Rhodotus palmatus and Xerocomus chrysenteron) from Northeast Portugal were studied for their chemical composition and antioxidant properties. Protocatechuic, p-hydroxybenzoic, p-coumaric and cinnamic acids were found in the phenolic fraction, ramnose, xylose, fucose, arabinose, fructose, glucose, manose, mannitol, sucrose, maltose and trehalose were quantified in polysaccharidic fraction, linoleic and stearic (only in Lactarius sp.) acids, and ÎČ- and Îł-tocopherols were the main compounds in the lipidic fraction. C. atramentaria and X. chrysenteron phenolic fractions gave the highest free radical scavenging activity, reducing properties and lipid peroxidation inhibition in brain homogenates, which is in agreement with its highest content in total phenolics. Furthermore, among the polysaccharidic fractions C. atramentaria also gave the highest antioxidant activity, which is accordingly with its highest total polysaccharides content and sugars obtained after hydrolysis.The authors are grateful to Fundação para a CiĂȘncia e a Tecnologia (FCT, Portugal) and COMPETE/QREN/EU (research project PTDC/AGR-ALI/110062/2009) for financial support. L. Barros (BPD/4609/2008) and S.A. Heleno (BD/70304/2010) also thank FCT, POPH-QREN and FSE. The GIP-USAL is financially supported by the Spanish Ministerio de Ciencia e InnovaciĂłn through the Consolider-Ingenio 2010 Programme (FUN-C-FOOD, CSD2007-00063), and Junta de Castilla y LeĂłn (Grupo de InvestigaciĂłn de Excelencia, GR133)
Not Available
Not AvailableThe purpose of the study was to discover whether incorporating flours with high nutritive value
along with pre-treatment of cereals with nixtamalization and sprouting of legumes would result in a highquality
healthy alternative for corn-based snacks.
Design/methodology/approach â Flours of nixtamalized cereals-corn, wheat, rice and sorghum and
sprouted legumes-soybean and green gram are made into dough and baked instead of fried to form multigrain
chips. The particle size and physical properties of flour and nutritional, functional and textural
properties of dough and chips are tested to study the effect of combination of nixtamalization of cereals and
sprouting of legumes in the development of chips.
Findings â Baked multi-grain chips made of nixtamalized cereals and sprouted legumes had a significantly
(p < 0.05) smaller particle size of 24.6 mm compared to T1 24.8 mm, C1 29.3 mm and C2 31.7 mm. T2 and C2
had significantly (p = 0.05) lower OAC value than C1 and T1 due to nixtamalization as nixtamalized flour
needed half the amount of oil during dough formation. T1 showed highest calcium (mg/100 g) of 466 which
was significantly (p < 0.05) higher than all other groups. The overall acceptability of T2 (8.6) was
significantly (p< 0.05) higher than T1 (7.8), C2 (7.4) and C1 (6.8) on the nine-point Hedonic scale.
Originality/value â The developed chips are superior in terms of higher protein and minerals with better
organoleptic acceptability and lower fat content in comparison to both corn chips and nixtamalized corn
chips. The multi-grain chip therefore offers a new option for the consumer in high-quality healthy alternative
to corn-based fried snacks.Not Availabl
Not Available
Not AvailableThe aim of the study was to develop gluten free
eggless cake using gluten free composite flour made of
finger millet, sprouted soy and amaranth, for patients with
celiac disease. Gluten free eggless cake prepared (T2),
were analyzed for physical, textural, rheological and
nutritional properties and compared with control cake
(C) made using refined wheat flour and eggs and eggless
composite flour cake made using whole wheat flour, malted
finger millet, sprouted soy flour and amaranth (T1). There
was no significant difference between T2 and C batter in
terms of textural properties, flow behaviour index and
consistency index. T2 had higher volume (454.4 cm3) as
compared to T1 (437.1 cm3) cake. No significant differences
in textural analysis were observed between cakes in
terms of springiness, resilience and cohesiveness. The
nutritional quality of T2 cake was significantly (p \ 0.05)
higher in case of phosphorous (224.0 mg / 100 g) and iron
content (7.39 mg / 100 g). Therefore, gluten free eggless
cake of high nutritional composition with good quality
characteristics is a good substitute for refined flour egg and
composite flour eggless cake. Higher mineral content due
to germinated ingredients also made it a nutritious and
palatable naturally gluten free food option for the people
with celiac disease.Not Availabl
Overview of second- and third-order nonlinear optical processes for deep imaging
The field of optical microscopic imaging has rapidly evolved because of tremendous advances made in laser and detection technology. Various types of linear and nonlinear light-matter interactions have been harnessed for providing contrast in the microscopic images. Simple microscopy techniques such as bright-field and differential-interference-contrast reveal structural information at the cellular level owing to the refractive index contrast of the sample medium. Fluorescence microscopy offers higher chemical specificity and is the most popular contrast mechanism used in biological studies. The contrast is achieved by means of targeted labeling of molecules using exogenous or endogenous fluorophores. However, external fluorophores are often perturbative since they may disrupt the native state of the sample, especially for small molecules whose size may be smaller than the fluorescent label itself. Besides, many molecular species are intrinsically nonfluorescent or only weakly fluorescent. It is also better to avoid external contrast agents for in vivo imaging applications since such contrast agents need concurrent development of appropriate delivery strategies and are often limited by problems of label specificity and induced toxicity. Vibrational microscopy techniques, on the other hand, are inherently label-free. They involve the excitation of molecular vibrations and offer intrinsic chemical specificity. Two such techniques include infrared absorption and Raman microscopy. Out of these, infrared microscopy has low spatial resolution owing to the long infrared wavelengths employed. In addition, water absorption of the infrared light is a major limitation for investigating live biological samples. Raman scattering, on the other hand, is based on the inelastic scattering of light by vibrating molecules and provides a molecular fingerprint of the chemical composition of a living cell or tissue. It offers a powerful label-free contrast mechanism and has been applied in various biological investigations. Linear contrast mechanisms based on fluorescence and Raman scattering typically employ continuous-wave visible light for excitation and sample scanning or laser scanning to generate an image. A confocal pinhole inserted at the detector facilitates a three-dimensionally sectioned image but unfortunately limits the sensitivity of detection
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