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排序方式: 共有262条查询结果,搜索用时 15 毫秒
1.
Reducing oxygen from 20% to 2.5% increases EGF-induced DNA synthesis and cell proliferation in cultures of human diploid fibroblasts. Reducing oxygen also changes the pattern of EGF binding to the cell surface. The loss of surface binding that follows EGF attachment to cells in 20% oxygen does not occur in 2.5% oxygen.  相似文献   
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An Ustilago maydis ergosterol biosynthesis mutant (A14) which is partially blocked in sterol 14alpha-demethylase (P45014DM) activity is described. This mutant accumulated the abnormal 14alpha-methyl sterols, eburicol, 14alpha-methylfecosterol, and obtusifoliol, along with significant amounts of ergosterol. Although the A14 mutant grew nearly as well as the wild type, it was impaired in cell extension growth, which indicated a dysfunction in apical cell wall synthesis. The mutant was also found to be hypersensitive to the azole fungicides penconazole and tebuconazole.  相似文献   
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Noden  Bruce H.  Cote  Noel M.  Reiskind  Michael H.  Talley  Justin L. 《EcoHealth》2021,18(4):475-486
EcoHealth - West Nile virus (WNV) is the most significant mosquito-borne disease affecting humans in the United States. Eastern redcedar (ERC) is a native encroaching plant in the southern Great...  相似文献   
7.
We describe here a computational morphology-based approach to the investigation of possible causes of chromatin alterations in sperm. A comprehensive set of state-of-the-art and geometric measures are computationally extracted from toluidine blue stained images and analyzed to infer the possible processes leading to normal and abnormal chromatin formation while seeking a possible taxonomy of chromatin alterations and their influence on sperm head morphology. Using this methodology, we have identified higher chromatin fragility at some specific points of the sperm head. Despite the lack of correlation between morphologies of sperm head and chromatin structure, four main morphological types of chromatin alterations in bull spermatozoa have been identified and their possible causes discussed.  相似文献   
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Hexazonium pararosaniline is a valuable reagent that has been used in enzyme activity histochemistry for 50 years. It is an aqueous solution containing the tris-diazonium ion derived from pararosaniline, an aminotriarylmethane dye, and it contains an excess of nitrous acid that was not consumed in the diazotization reaction. Other investigators have found that immersion for 2 min in an acidic (pH 3.5) 0.0015 M hexazonium pararosaniline solution can protect cryostat sections of unfixed animal tissues from the deleterious effects of aqueous reagents such as buffered solutions used in immunohistochemistry, while preserving specific affinities for antibodies. In the present investigation hexazonium pararosaniline protected lymphoid tissue and striated muscle against the damaging effects of water or saline. The same protection was conferred on unfixed sections treated with dilute nitrous or hydrochloric acid in concentrations similar to those in hexazonium pararosaniline solutions. Model tissues (solutions, gels or films containing gelatin and/or bovine albumin) responded predictably to well known cross-linking (formaldehyde) or coagulant (mercuric chloride) fixatives. Hexazonium pararosaniline solutions prevented the dissolution of protein gels in water only after 9 or more days of contact, during which time considerable swelling occurred. It is concluded that there is no evidence for a “fixative” action of hexazonium pararosaniline. The protective effect on frozen sections of unfixed tissue is attributable probably to the low pH of the solution.  相似文献   
9.

Background and Objectives

Following the 2010 earthquake in Haiti, infant and young child feeding was identified as a priority nutrition intervention. A new approach to support breastfeeding mothers and distribute ready-to-use infant formula (RUIF) to infants unable to breastfeed was established. The objective of the evaluation was to assess the implementation of infant feeding programs using RUIF in displaced persons camps in Port-au-Prince, Haiti during the humanitarian response.

Methods

A retrospective record review was conducted from April–July, 2010 to obtain data on infants receiving RUIF in 30 baby tents. A standardized data collection form was created based on data collected across baby tents and included: basic demographics, admission criteria, primary caretaker, feeding practices, and admission and follow-up anthropometrics.

Main Findings

Orphans and abandoned infants were the most frequent enrollees (41%) in the program. While the program targeted these groups, it is unlikely that this is a true reflection of population demographics. Despite programmatic guidance, admission criteria were not consistently applied across programs. Thirty-four percent of infants were undernourished (weight for age Z score <−2) at the time of admission. Defaulting accounted for 50% of all program exits and there was no follow-up of these children. Low data quality was a significant barrier.

Conclusions

The design, implementation and magnitude of the ‘baby tents’ using RUIF was novel in response to infant and young child feeding (IYCF) in emergencies and presented multiple challenges that should not be overlooked, including adherence to protocols and the adaption of emergency programs to existing programs. The implementation of IYCF programs should be closely monitored to ensure that they achieve the objectives set by the humanitarian community and national government. IYCF is an often overlooked component of emergency preparedness; however to improve response, generic protocols and pre-emergency training and preparedness should be established for humanitarian agencies.  相似文献   
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