为什么显示器也需要通过Vista认证

最近有些读者朋友问：现在微软为什么这么霸道,连显示器都要通过它的认证,没有通过Windows Vista认证的液晶显示器会有什么不同吗？液晶显示器和Windows Vista操作系统之间到底有什么必要的联系呢？通过Windows Vista认证的显示器又有什么好处呢？针对上述种种疑问,今天我们将为大家一一解答。     

Contribution of h-bonding to the preference of platinum anti-tumour drugs for particular bases and particular cross-links

The stereochemical factors that influence the tendencies for sequence specific binding of platinum antitumour drugs to DNA are examined. The NHs of the platinum-amine moiety can form hydrogen bonds to the O6 of guanine or to a phosphate oxygen of DNA. Modelling the stereochemistry of the NH atoms can lead to compounds with a strong preference for forming one type of adduct with DNA.     

Consumer demands: Major problems facing industry in a consumer-driven society

Demand is driven by conventional market forces over much of the world among consumers with strong positive attitudes to meat as a nutritious, tasty and premium food; price in relation to income, availability, quality (including leanness) and relevance to life-style remain the dominant forces operating. But in the developed world, there are emerging concerns about how meat is produced, which are likely to have negative effects on demand, particularly that of the current younger generation, and which may well begin to affect Government policies towards the meat industry. The industry needs to establish strong information and education programmes, but also to examine its procedures to provide greater consumer assurance about practises and controls. Also the scientists and technologists serving the industry need to help it move towards sustainable lower input, less environmentally damaging systems, less reliance on drugs, stimulants and additives, sensitive exploitation of the new genetics and with more consideration for the animals involved.     

Calcium chloride in vitro effects on isolated myofibrillar proteins

The objective of this study was to determine the effect of 30 mM CaCl(2) on the solubilization of those structural proteins that contribute to myofibril stability. Ovine M. longissimus dorsi (longissimus) samples were obtained immediately post-exsanguination, myofibrils were isolated, glycerated, and frozen until needed. Myofibrils were washed, diluted and incubated in 0·1 m KCl, 10 mm Tris, pH 7·0 buffer for 24, 48 and 72 h. Treatments consisted of: (1) control, (2) 1 mm E(64), (3) 30 mm CaCl(2), and (4) 1 mm E(64) + 30 mm CaCl(2). Results (SDS-PAGE) indicated that myosin heavy chain (though not to a great extent), M-protein, C-protein, α-actinin, actin, troponin-T, tropomyosin isoforms, troponin-I and 72, 70, 62, 33, 32, 30, and 22 kDa unidentified bands were solubilized from myofibrils incubated in KCl buffer for 72 h. The addition of CaCl(2) hastened the appearance of some of the proteins in the supernatant fractions, but no differences were observed at 72 h among the treatments. The addition of E(64) had no effect on which proteins were released. Thus, in the absence of proteolysis it appears that a general solubilization of thick-and-thin filament ancillary proteins occurs in the presence of 30 mm CaCl(2). However, the contribution to tenderness should be minimal, because solubilized proteins are not part of the cytoskeletal elements that are responsible for maintaining structural integrity of the tissue.     

The countrate performance of the volume imaging PENN-PET scanner

The UGM PENN-PET camera uses large position sensitive detectors and operates without septa. This design results in high sensitivity and 3-D imaging capability, but poses problems in high countrate situations. The maximum true countrates and random countrates have been measured, as a function of object size in the field-of-view. The countrate performance is understood in terms of the limiting process rates and event rejection in the camera. In addition, the camera is calibrated to generate absolute activity concentrations to within 5% by correcting for system deadtime with up to 3 mCi in the field of view in brain studies (50% deadtime at 3 muCi/mL). This allows the performance of a variety of brain and body studies, and accurate quantitation of the data over a wide range of imaging countrates, from (18)F-FDG brain studies to (15)O-water dynamic brain studies.     

Design method of an astronomical telescope with reduced sensitivity to misalignment

Approximate formulas are derived for the axial coma resulting from tilt and decenter of a surface and for the spherical aberration resulting from a change in its axial position. These expressions include terms that represent aberrations induced by the subsystem preceding the surface in addition to other terms that are intrinsic contributions from the misaligned surface itself. This separation of the terms gives a simple method of designing a system that is insensitive to a misalignment at a given surface. The method is illustrated by applying it to a two-mirror astronomical telescope with corrector. Two examples are given-one for tilt and the other for despace. In both examples an appreciable reduction in the sensitivity is obtained. The limitations of these solutions and the problem of simultaneous correction for two types of misalignment are examined.     

Electro-optic high-resolution Fabry-Perot spectrometer

A single-crystal lithium niobate dtalon suitable for high-spectral-resolution studies has been operated successfully. This étalon with a 5-cm clear diameter and a gap equivalent to 2 cm in air has been found to have very linear response in wave number as a function of voltage. The combined advantages of adjustment-free operation, linearity in operation, and high luminosity in a small size (as a result of the μ(2) gain in the instrumental throughput caused by the large index of refraction of the lithium niobate substrate) make for a rugged instrument that is ideal for long-term unattended field operation.