The mouse embryo culture system: improving the sensitivity for use as a quality control assay for human in vitro fertilization

Endurance training leads to an increase in the content of individual mitochondrial hemeproteins in skeletal muscle. To deduce the control mechanisms involved, cytochrome oxidase (COX) activity was compared with 1) the content of COX subunits III and IV and 2) 5-aminolevulinate synthase (ALAS) activity and mRNA content. In the plantaris muscle of female rats run daily for up to 28 days, ALAS activity was elevated 100% (P < 0.01) after 3 days and remained 150 and 125% higher (P < 0.001) after 7 and 28 days of running, respectively, than control. COX activity was also increased, but not until day 7 (40%; P < 0.05), and reached a maximal value 80% higher than control (P < 0.001) in the 28-day group. Compared with control, the content of COX subunit III and IV and ALAS mRNAs was not significantly changed by the training. The increased activities of COX and ALAS appear to be regulated by translational or posttranslational steps in the protein expression pathway. The induction of ALAS before COX suggests that the increased activity of COX may require increased synthesis of heme.     

Accurate solid modeling using polyhedral approximations

Although curved-surface solid modeling systems achieve a higher level of accuracy than faceted systems, they also introduce a host of topological, geometric, and numerical complications. A method for calculating accurate boundary representations of solid models is introduced that reduces the impact of these complications. The method uses a pair of bounding polyhedral approximations to enclose the boundary of each object. A structural analysis automatically determines where to make adaptive refinements to the polyhedrons to assure the topological validity of the results. Potential singularities are localized. The implementation is an experimental extension to the Geometric Design Processor (GDP) solid modeling system     

Advances in ALCHEMI analysis

The ALCHEMI method for locating the sites of foreign atoms within crystals is known to be sensitive to the delocalized emission of X-rays. This can result in large errors in some cases through differences in delocalization for different excitations or by error amplification in the ratio method of analysis. An alternative approach to the analysis of ALCHEMI data, using multivariate statistical analysis, is extended to the case of multiple impurities. Initial results from zone-axis channelling experiments for a Yb-doped zirconolite (CaZrTi₂O₇) are shown to confirm the improved accuracy of this method, especially for axial orientations. Data were collected using a 400-keV analytical electron microscope fitted with an intrinsic Ge X-ray detector. The potential advantages for ALCHEMI analysis of Ge detectors are considered.     

项目成功标准(上)

导言 对于项目经理而言,项目成功是一个非常重要的问题.John Wateridge先生在其出版的一本著作(1995)[1]中谈到(我在其他地方也阐述过Turner,1999[2],Turner,2000[3]),有一个最为重要的因素决定着项目的成功.如果你不这样做,注定会走向失败;如果按照要求做,成功机会便会大大增加(尽管一些其他不利因素也可能会导致失败).     

Non-peptidic HIV protease inhibitors: C2-symmetry-based design of bis-sulfonamide dihydropyrones

Potent, non-peptidic, dihydropyrone sulfonamide HIV protease inhibitors have been previously described. Crystallographic analysis of dihydropyrone sulfonamide inhibitor/HIV protease complexes suggested incorporation of a second, C2 symmetry-related sulfonamide group. Selected bis-sulfonamide dihydropyrone analogues display high HIV protease inhibitory activity.     

Acute arthritis of cats associated with feline calicivirus infection

Twelve specific pathogen-free cats were infected either by intra-articular inoculation or by contact exposure to one of two strains of feline calicivirus (FCV), either F65, a field strain originating from an outbreak of lameness in a group of cats, or a vaccine strain. Following either route of exposure, both strains induced signs typical of FCV infection including oral and nasal ulceration, conjunctivitis and ocular discharge. These signs were of equal severity for both virus strains, but overall, following either route of infection, F65 induced more severe disease than the vaccine strain, with marked pyrexia, lethargy and lameness. Vaccine virus only induced a relatively mild lameness following intra-articular inoculation. Gross pathological and histopathological lesions were seen in some of the joints, but again changes were more severe in the F65-exposed cats. Virus was isolated from both normal and affected joints from both groups of F65-exposed cats, and from a joint from each cat inoculated intra-articularly with vaccine virus. Mild transient lameness was also seen in one of two control cats inoculated intra-articularly, but no pathological changes were seen or virus isolated from joints. A cDNA probe used in RNA dot blot hybridisation experiments was found to be specific and more sensitive than virus isolation in detecting FCV in selected tissues. This may be useful in future studies on the pathogenesis of FCV disease and in studies on viral persistence in FCV carriers.