Home About us Contact
|
Home About us Contact | ||
|
|
||
Common Defects (common + defect)
Selected AbstractsHOXA13 directly regulates EphA6 and EphA7 expression in the genital tubercle vascular endotheliaDEVELOPMENTAL DYNAMICS, Issue 4 2007Carley A. Shaut Abstract Hypospadias, a common defect affecting the growth and closure of the external genitalia, is often accompanied by gross enlargements of the genital tubercle (GT) vasculature. Because Hoxa13 homozygous mutant mice also exhibit hypospadias and GT vessel expansion, we examined whether genes playing a role in angiogenesis exhibit reduced expression in the GT. From this analysis, reductions in EphA6 and EphA7 were detected. Characterization of EphA6 and EphA7 expression in the GT confirmed colocalization with HOXA13 in the GT vascular endothelia. Analysis of the EphA6 and EphA7 promoter regions revealed a series of highly conserved cis -regulatory elements bound by HOXA13 with high affinity. GT chromatin immunoprecipitation confirmed that HOXA13 binds these gene-regulatory elements in vivo. In vitro, HOXA13 activates gene expression through the EphA6 and EphA7 gene-regulatory elements. Together these findings indicate that HOXA13 directly regulates EphA6 and EphA7 in the developing GT and identifies the GT vascular endothelia as a novel site for HOXA13-dependent expression of EphA6 and EphA7. Developmental Dynamics 236:951,960, 2007. © 2007 Wiley-Liss, Inc. [source] Factors affecting the formation of misoriented domains in 6H-SiC single crystals grown by PVT methodCRYSTAL RESEARCH AND TECHNOLOGY, Issue 4 2009T. H. Peng Abstract Misoriented domains (MDs) are common defects in 6H-SiC single crystals. We performed an experimental study on the formation of MDs in 2-inch 6H-SiC single crystals. Micro-Raman spectroscopy revealed that the polytype of MDs was mainly 4H-SiC. By changing growth conditions, it was found that the MDs' formation was closely related to growth rate and the position of highest temperature relative to growth interface. When the growth rate of ingots was relatively high the MDs were more likely to form. Furthermore, the nearer growth interface the position of highest temperature was, the larger the size of the MDs. Based on our experimental findings we suggested that the MDs' formation and the polytype switching from 6H- to 4H-SiC were due to too large axial and/or radial temperature gradients. The results would be helpful to improve the quality of SiC single crystals grown by PVT technique. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] CONSUMER PERCEPTION OF SANDINESS IN DULCE DE LECHEJOURNAL OF SENSORY STUDIES, Issue 2 2008ANA GIMÉNEZ ABSTRACT Sandiness, one of the most common defects of dulce de leche, is caused by lactose crystallization. In order to study consumer reaction to the presence of different levels of this defect, survival analysis statistics was applied to the consumer acceptance/rejection data of the samples. Limits for this defect were estimated by working with 10% and 25% consumer rejection probabilities. The consumers were also asked to score the sample sandiness according to their perception, using a 9-point scale. Cluster analysis and correspondence analysis performed showed the heterogeneity of the consumer responses toward sandiness in dulce de leche. Significant correlations were established between consumer sandiness and the number of crystals and sandiness as measured by a panel of trained assessors, the latter being the best indicator of sandiness as perceived by the consumers. It could be established that the consumers' and assessors' sandiness perception is clearly influenced by the presence of agglomerates, their size distribution and number. PRACTICAL APPLICATIONS Sandiness is an important defect for a segment of consumers who rejected samples with high levels of sandiness, suggesting the importance of avoiding the occurrence of this defect. Survival analysis methodology was used to estimate the maximum level of sandiness in dulce de leche before consumers reject it. As sandiness is a sensory defect that often limits the shelf life of dulce de leche, the calculated sensory limits could be used in future studies to estimate the sensory shelf life of dulce de leche. [source] Congenital Cardiac Defects in Neonatal Foals: 18 Cases (1992,2007)JOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 1 2010T.L. Hall Background: Literature available regarding congenital cardiac defects in foals is limited to reports of individual cases or small case series. Objective: To describe the clinical, echocardiographic, and necropsy findings and breed predilection of congenital cardiac defects in neonatal foals. Animals: Eighteen foals <15 days of age with 1 or more congenital cardiac defects. Methods: Medical records of foals diagnosed with congenital cardiac defects at the William R. Pritchard Veterinary Medical Teaching Hospital were reviewed. Data collected included history, signalment, clinical signs, laboratory data, diagnostic and necropsy results, and outcome. Results: Arabian foals represented 39% of cases with congenital cardiac defects and were significantly (P= .004) overrepresented (OR = 4.7 [CI: 1.8,12.4]) compared with the general hospital population. Ventricular septal defect (VSD) (14/18), tetralogy of Fallot (5/18), and tricuspid valve atresia (4/18) were the most common defects identified. A ,3/6 heart murmur (14/14) accompanied by tachycardia (14/17), tachypnea (17/17), and cyanosis of mucous membranes (7/16) were the most common clinical signs. Concurrent congenital defects were common (9/18). Two foals, both with VSD, survived for , 8 years after diagnosis and 1 was a successful performance horse. Conclusions and Clinical Relevance: Arabian horses appear to have a predisposition for cardiac defects. The presence of a loud murmur (, 3/6), cyanotic membranes, and tachycardia or tachypnea in a neonatal foal should warrant thorough evaluation of the heart for congenital defects. Foals with cardiac defects should be closely evaluated for concurrent congenital defects in other body systems. [source] Assessing teratogenicity of antiretroviral drugs: monitoring and analysis plan of the Antiretroviral Pregnancy Registry,,PHARMACOEPIDEMIOLOGY AND DRUG SAFETY, Issue 8 2004Deborah L. Covington DrPH Abstract This paper describes the Antiretroviral Pregnancy Registry's (APR) monitoring and analysis plan. APR is overseen by a committee of experts in obstetrics, pediatrics, teratology, infectious diseases, epidemiology and biostatistics from academia, government and the pharmaceutical industry. APR uses a prospective exposure-registration cohort design. Clinicians voluntarily register pregnant women with prenatal exposures to any antiretroviral therapy and provide fetal/neonatal outcomes. A birth defect is any birth outcome ,20 weeks gestation with a structural or chromosomal abnormality as determined by a geneticist. The prevalence is calculated by dividing the number of defects by the total number of live births and is compared to the prevalence in the CDC's population-based surveillance system. Additionally, first trimester exposures, in which organogenesis occurs, are compared with second/third trimester exposures. Statistical inference is based on exact methods for binomial proportions. Overall, a cohort of 200 exposed newborns is required to detect a doubling of risk, with 80% power and a Type I error rate of 5%. APR uses the Rule of Three: immediate review occurs once three specific defects are reported for a specific exposure. The likelihood of finding three specific defects in a cohort of ,600 by chance alone is less than 5% for all but the most common defects. To enhance the assurance of prompt, responsible, and appropriate action in the event of a potential signal, APR employs the strategy of ,threshold'. The threshold for action is determined by the extent of certainty about the cases, driven by statistical considerations and tempered by the specifics of the cases. Copyright © 2004 John Wiley & Sons, Ltd. [source] | ||||||||||