253 research outputs found

    Wrinkling and developable cones in centrally confined sheets

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    Thin sheets respond to confinement by smoothly wrinkling, or by focusing stress into small, sharp regions. From engineering to biology, geology, textiles, and art, thin sheets are packed and confined in a wide variety of ways, and yet fundamental questions remain about how stresses focus and patterns form in these structures. Using experiments and molecular dynamics (MD) simulations, we probe the confinement response of circular sheets, flattened in their central region and quasi-statically drawn through a ring. Wrinkles develop in the outer, free region, then are replaced by a truncated cone, which forms in an abrupt transition to stress focusing. We explore how the force associated with this event, and the number of wrinkles, depend on geometry. Additional cones sequentially pattern the sheet, until axisymmetry is recovered in most geometries. The cone size is sensitive to in-plane geometry. We uncover a coarse-grained description of this geometric dependence, which diverges depending on the proximity to the asymptotic d-cone limit, where the clamp size approaches zero. This work contributes to the characterization of general confinement of thin sheets, while broadening the understanding of the d-cone, a fundamental element of stress focusing, as it appears in realistic settings.Comment: 11 pages, 9 figure

    Anesthetic effect of tricaine methanesulfonate, clove oil and electroanesthesia on lysozyme activity of Oncorhynchus mykiss

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    There is a few available information about the effect of anesthetics, specially electroanesthesia on immune parameters in fish. In the present work, two anesthetics, MS222 (50 ppm), clove oil (25 ppm), and electroanesthesia were tested in rainbow trout (Oncorhynchus mykiss) in narcosis stage. The results showed, clove oil and electroanesthesia increase the lysozyme activity 24 h after anesthesia(p0.05). It seems use of MS222 during aquacultural practices may induce lesser effect in rainbow trout

    CSNL: A cost-sensitive non-linear decision tree algorithm

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    This article presents a new decision tree learning algorithm called CSNL that induces Cost-Sensitive Non-Linear decision trees. The algorithm is based on the hypothesis that nonlinear decision nodes provide a better basis than axis-parallel decision nodes and utilizes discriminant analysis to construct nonlinear decision trees that take account of costs of misclassification. The performance of the algorithm is evaluated by applying it to seventeen datasets and the results are compared with those obtained by two well known cost-sensitive algorithms, ICET and MetaCost, which generate multiple trees to obtain some of the best results to date. The results show that CSNL performs at least as well, if not better than these algorithms, in more than twelve of the datasets and is considerably faster. The use of bagging with CSNL further enhances its performance showing the significant benefits of using nonlinear decision nodes. The performance of the algorithm is evaluated by applying it to seventeen data sets and the results are compared with those obtained by two well known cost-sensitive algorithms, ICET and MetaCost, which generate multiple trees to obtain some of the best results to date. The results show that CSNL performs at least as well, if not better than these algorithms, in more than twelve of the data sets and is considerably faster. The use of bagging with CSNL further enhances its performance showing the significant benefits of using non-linear decision nodes

    Effect of different levels of sunflower meal and multi-enzyme complex on performance, biochemical parameters and antioxidant status of laying hens

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    This study was designed to evaluate the effects of different sunflower meal (Helianthus annus; SFM) levels and a multi-enzyme complex (Natuzyme P50) on performance, biochemical parameters and antioxidant status of laying hens. A total of 288 Hy-Line W-36 laying hens (39-wk-old) were divided into six groups with six replicates per group (eight birds per replicate) and fed one of the six experimental diets. A corn-soybean meal-based diet was formulated and used as control diet. The experimental treatments consisted of three levels of SFM (0, 10, and 20%) and two levels of multi-enzyme complex (0 and 250g/ton). The feeding trial lasted 10 weeks. The results showed that the egg production, egg weight and mass, egg specific gravity, shell strength and thickness, Haugh unit, shape index, triglyceride content, plasma glutathione peroxidase (GSH) activity, and malondialdehyde (MDA) were not influenced by dietary treatments; however, the feed consumption, yolk cholesterol, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol were significantly affected by feeding SFM compared to the control. In conclusion, the supplementation of SFM up to 20% in diet with multi-enzyme complex in laying hens did not appear to cause any adverse effects on egg production and quality as well on antioxidant status in laying hens.Keywords: Enzymes, laying hen, performance, sunflower meal, yolk cholestero

    Evaluation of mRNA expression levels of cyp51a and mdr1, candidate genes for voriconazole resistance in Aspergillus flavus

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    Background: Voriconazole Resistance (VRC-R) in Aspergillus flavus isolates impacts the management of aspergillosis, since azoles are the first choice for prophylaxis and therapy. However, to the best of our knowledge, the mechanisms underlying voriconazole resistance are poorly understood. Objectives: The present study was designed to evaluate mRNA expression levels of cyp51A and mdr1 genes in voriconazole resistant A. flavus by a Real-Time Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) technique. Materials and Methods: Five A. flavus isolates with resistance to VRC were examined by a RT-PCR approach. Results: Four out of five isolates revealed cyp51A and mdr1 mRNA overexpression. Interestingly, the isolate, which was negative for cyp51A and mdr1 mRNA expression showed a high voriconazole Minimum Inhibitory Concentration (MIC). Furthermore, a computational-based analysis predicted that voriconazole resistance could be mediated through cooperation with a network protein interaction. Conclusions: Our experimental and in silico findings may provide new insight in the complex molecular pathways of drug resistance and also could assist design an efficient therapeutic strategy for aspergillosis treatment. © 2015 Ahvaz Jundishapur University of Medical Sciences

    Prevalence and risk factor's analysis of bovine brucellosis in peri-urban areas under intensive system of production in Gujarat, India

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    Aim: A study on surveillance of bovine brucellosis in dairy herds of peri-urban areas under intensive system of production was carried out by milk-ELISA. Various risk factors were identified having significant association with occurrence of bovine brucellosis in dairy herds of peri-urban areas. Materials and Methods: Five randomly selected peri-uban areas of six cities of Gujarat were included in the present study. Five randomly selected dairy herds under intensive system of production from each selected peri-urban area were included for further investigation. In total, 199 bulk and 582 individual milk samples were screened by milk-ELISA. Forty three different risk factors were identified and grouped into four major categories as general characteristics of farms, introduction of infection to farms, management systems of farms and exposure of disease. Further, their distribution and association with prevalence of bovine brucellosis was studied. Results: The overall herd and animal prevalence in peri-urban areas was 33.70 and 11.90%, respectively. Out of 11 risk factors on general characteristics of dairy farms, only five (herd size, type of animals, type of breed, age of owner and knowledge gained by owners) showed significant (p<0.05) association with occurrence of bovine brucellosis. None of risk factors on introduction of infection to farms (n=6) and management systems of farms (n=11) was found significantly associated with occurrence of brucellosis. Among risk factors on exposure of disease (n=15), history of abortion, retention of placenta, still birth and metritis/endometritis showed significant (p<0.05) association with prevalence of bovine brucellosis. Conclusion: It was concluded that prevalence of bovine brucellosis in dairy herds under intensive system of production in peri-urban areas of Gujarat was comparatively higher than reported overall prevalence of brucellosis. Risk factors like larger herd in close confinement without adequate sheds, type of animal, type of breed and knowledge/awareness of dairyman, unrestricted animal market, replacement without prior testing, reproductive disorders with absence of their testing are the important risk factors under the intensive production system of peri-urban areas of Gujarat, India

    Tissue-engineered tracheal replacement in a child: a 4-year follow-up study

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    In 2010, a tissue-engineered trachea was transplanted into a 10-year-old child using a decellularized deceased donor trachea repopulated with the recipient's respiratory epithelium and mesenchymal stromal cells. We report the child's clinical progress, tracheal epithelialization and costs over the 4 years. A chronology of events was derived from clinical notes and costs determined using reference costs per procedure. Serial tracheoscopy images, lung function tests and anti-HLA blood samples were compared. Epithelial morphology and T cell, Ki67 and cleaved caspase 3 activity were examined. Computational fluid dynamic simulations determined flow, velocity and airway pressure drops. After the first year following transplantation, the number of interventions fell and the child is currently clinically well and continues in education. Endoscopy demonstrated a complete mucosal lining at 15 months, despite retention of a stent. Histocytology indicates a differentiated respiratory layer and no abnormal immune activity. Computational fluid dynamic analysis demonstrated increased velocity and pressure drops around a distal tracheal narrowing. Cross-sectional area analysis showed restriction of growth within an area of in-stent stenosis. This report demonstrates the long-term viability of a decellularized tissue-engineered trachea within a child. Further research is needed to develop bioengineered pediatric tracheal replacements with lower morbidity, better biomechanics and lower costs

    Identification of Azole Resistance Markers in Clinical Isolates of Candida tropicalis Using cDNA-AFLP Method

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    Background: Global reports have highlighted the increasing prevalence of Candida tropicalis infections as well as organism's drug resistance. This study aimed at identifying azole resistance markers in clinical isolates of C. tropicalis, which will be a great resource for developing new drugs. Methods: Two susceptible and resistant isolates of C. tropicalis were recovered from an epidemiological investigation of candidiasis in immunocompromised patients. C. tropicalis ATCC 750 was used as reference strain. Antifungal susceptibility to fluconazole and itraconazole was determined using Clinical and Laboratory Standards Institute (CLSI) method. Complementary DNA-amplified fragment length polymorphism (cDNA-AFLP) technology and real-time reverse-transcriptase (RT) PCR were used for identification of potential genes involved in azole resistance of C. tropicalis clinical isolates. Results: Five genes encoding the following enzymes were identified as superoxide dismutase (SOD) implicated in antioxidant defense, ornithine aminotransferase (OAT), acetyl ornithine aminotransferase (ACOAT), adenosylmethionine-8-amino-7-oxononanoate aminotransferase (DAPA AT), and 4-aminobutyrate aminotransferase (ABAT)-belonging to pyridoxal phosphate (PLP) dependent enzymes and acting in an important physiological role in many fungal-cell cycles. Real-time RT-PCR confirmed mRNA level of the aforementioned genes. Conclusion: Our findings showed that factors such as PLP-dependent enzymes and SOD might be implicated in drug resistance in C. tropicalis clinical isolate. Therefore, further studies are required to explore the accurate biological functions of the mentioned genes that would be helpful for effective drug development. © 2016 Wiley Periodicals, Inc
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