Modeling, Optimization, and Flow Visualization of Chemical Etching Process in Niobium Cavities

Niobium cavities are important component of the linear accelerators. Researchers have concluded that buffered chemical polishing on the inner surface of the cavity improves its performance. However the mechanism of chemical polishing is not well understood. A finite element computational fluid dynamics (CFD) model was developed to simulate the fluid flow characteristics of chemical etching process inside the cavity. The CFD model is then used to optimize the baffle design. The analysis confirmed the observation of other researchers that the iris section of the cavity received more etching than the equator regions. The baffle, which directs flow towards the walls of the cavity, was redesigned using optimization techniques. The redesigned baffle significantly improves the performance of the etching process. To verify these results an experimental setup for flow visualization was created. The setup consists of a high speed, high resolution CCD camera. The camera is positioned by a computer controlled traversing mechanism. A dye injecting arrangement is used for tracking the fluid path. The Experimental results are, in general, in agreement with the CFD and the optimization data

Genome-wide association study of Arabidopsis thaliana leaf microbial community

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An Adaptable Two-Color Flow Cytometric Assay to Quantitate the Invasion of Erythrocytes by Plasmodium falciparum Parasites

Plasmodium falciparum genotyping has recently undergone a revolution, and genome-wide genotype datasets are now being collected for large numbers of parasite isolates. By contrast, phenotyping technologies have lagged behind, with few high throughput phenotyping platforms available. Invasion of human erythrocytes by Plasmodium falciparum is a phenotype of particular interest because of its central role in parasite development. Invasion is a variable phenotype influenced by natural genetic variation in both the parasite and host and is governed by multiple overlapping and in some instances redundant parasite–erythrocyte interactions. To facilitate the scale-up of erythrocyte invasion phenotyping, we have developed a novel platform based on two-color flow cytometry that distinguishes parasite invasion from parasite growth. Target cells that had one or more receptors removed using enzymatic treatment were prelabeled with intracellular dyes CFDA-SE or DDAO-SE, incubated with P. falciparum parasites, and parasites that had invaded either labeled or unlabeled cells were detected with fluorescent DNA-intercalating dyes Hoechst 33342 or SYBR Green I. Neither cell label interfered with erythrocyte invasion, and the combination of cell and parasite dyes recapitulated known invasion phenotypes for three standard laboratory strains. Three different dye combinations with minimal overlap have been validated, meaning the same assay can be adapted to instruments harboring several different combinations of laser lines. The assay is sensitive, operates in a 96-well format, and can be used to quantitate the impact of natural or experimental genetic variation on erythrocyte invasion efficiency. © 2010 International Society for Advancement of Cytometr

Hypoglycemic Effect of Macrocyclic Binuclear Oxovanadium (IV) Complex on Streptozotocin-Induced Diabetic Rats

Though vanadium complexes mimic the action of insulin, owing to their toxicity, research is still in progress for a new vanadium complex with maximum efficacy at low concentration and without any side effects. A novel macrocyclic binuclear oxovanadium complex was synthesized, its composition and structure were confirmed by spectral studies and its efficacy was studied in streptozotocin-induced diabetic rats over a period of 30 days. The oral administration of the complex normalizes the blood glucose level in the diabetic rats and also maintains normoglycemia after a glucose load. The biochemical studies revealed that the complex is not toxic to the system. The nontoxic nature of this complex may be due to the presence of the vanadyl ions in an intact form. The study highlights the nontoxic and hypoglycemic effects of the new macrocyclic binuclear oxovanadium complex

Recombinant anticoccidial vaccines - a cup half full?

Eimeria species parasites can cause the disease coccidiosis, most notably in chickens. The occurrence of coccidiosis is currently controlled through a combination of good husbandry, chemoprophylaxis and/or live parasite vaccination; however, scalable, cost-effective subunit or recombinant vaccines are required. Many antigens have been proposed for use in novel anticoccidial vaccines, supported by the capacity to reduce disease severity or parasite replication, increase body weight gain in the face of challenge or improve feed conversion under experimental conditions, but none has reached commercial development. Nonetheless, the protection against challenge induced by some antigens has been within the lower range described for the ionophores against susceptible isolates or current live vaccines prior to oocyst recycling. With such levels of efficacy it may be that combinations of anticoccidial antigens already described are sufficient for development as novel multi-valent vaccines, pending identification of optimal delivery systems. Selection of the best antigens to be included in such vaccines can be informed by knowledge defining the natural occurrence of specific antigenic diversity, with relevance to the risk of immediate vaccine breakthrough, and the rate at which parasite genomes can evolve new diversity. For Eimeria, such data are now becoming available for antigens such as apical membrane antigen 1 (AMA1) and immune mapped protein 1 (IMP1) and more are anticipated as high-capacity, high-throughput sequencing technologies become increasingly accessible

Herpetofaunal mortality due to vehicular traffic in the Western Ghats, India: a case study

We monitored the mortality of herpetofauna on a fortnightly basis along National Highway 220, which cuts across the Western Ghats, India, during December 2006- November 2007. In all, 101 amphibians (3.5 amphibians/ 10km) belonging to six taxa and 78 reptiles (2.7 reptiles/ 10 km) of 23 taxa were found dead in 48 surveys. The mortality of amphibians during day and night was significantly different (Z= 3.12, n1= 24, n2= 24, P < 0.01), whereas this was not so with respect to reptiles. The difference in the mortality of amphibians between seasons was not significant, but it was significant with respect to reptiles (Z= -1.188, n1= 24, n2= 24, p< 0.05). Overall, the road kills of amphibians were significantly correlated with that occurring in nearby forests (r = 0.67, n= 12, P< 0.01), but reptiles had no such relationship. The number of road kills of amphibians and reptiles on a monthly basis was not correlated with the intensity of vehicle plying on the road. Key Words: Biodiversity hotspot, Asia, amphibians, reptiles, road kills. Resumen: Mortalidad de herpetofauna debido a tráfico vehicular en los Western Ghats, India: un caso de estudio Monitoreamos la mortalidad de herpetofauna sobre una base bi-semanal a lo largo de la Autopista Nacional 220 que atraviesa los Western Ghats, India, durante diciembre 2006- noviembre 2007. En total, 101 anfibios (3.5 anfibios/ 10km) pertenecientes a seis taxones, y 78 reptiles (2.7 reptiles/ 10 km) de 23 taxones fueron encontrados muertos en 48 muestreos. La mortalidad de los anfibios durante el día y la noche fue significativamente diferente (Z= 3.12, n1= 24, n2= 24,

A sparse covarying unit that describes healthy and impaired human gut microbiota development

Characterizing the organization of the human gut microbiota is a formidable challenge given the number of possible interactions between its components. Using a statistical approach initially applied to financial markets, we measured temporally conserved covariance among bacterial taxa in the microbiota of healthy members of a Bangladeshi birth cohort sampled from 1 to 60 months of age. The results revealed an ecogroup of 15 covarying bacterial taxa that provide a concise description of microbiota development in healthy children from this and other low-income countries, and a means for monitoring community repair in undernourished children treated with therapeutic foods. Features of ecogroup population dynamics were recapitulated in gnotobiotic piglets as they transitioned from exclusive milk feeding to a fully weaned state consuming a representative Bangladeshi diet

Effects of microbiota-directed foods in gnotobiotic animals and undernourished children

To examine the contributions of impaired gut microbial community development to childhood undernutrition, we combined metabolomic and proteomic analyses of plasma samples with metagenomic analyses of fecal samples to characterize the biological state of Bangladeshi children with severe acute malnutrition (SAM) as they transitioned, after standard treatment, to moderate acute malnutrition (MAM) with persistent microbiota immaturity. Host and microbial effects of microbiota-directed complementary food (MDCF) prototypes targeting weaning-phase bacterial taxa underrepresented in SAM and MAM microbiota were characterized in gnotobiotic mice and gnotobiotic piglets colonized with age- and growth-discriminatory bacteria. A randomized, double-blind controlled feeding study identified a lead MDCF that changes the abundances of targeted bacteria and increases plasma biomarkers and mediators of growth, bone formation, neurodevelopment, and immune function in children with MAM