八记：设计，帮助客户建立价值感

Q：能谈谈你对国内手机设计这方面的认识吗？ A——现在手机设计这方面．早期延伸的是日本的路子．现在基本上是韩国的路子。中国人本身对日本的东西有些抵触心理．严格意义上讲中国有手机设计外观是近三到四年左右出现的。三四年前．中国国产手机品牌几乎80％以上都是从韩国或台湾拿的方案．有些从日本拿的，但很少。现在基本上国内都已经发展起来了．再从外面拿方案的已经很少了．现在占的系数应该是200左右。     

Plasma clearance of cholyl-lysyl-fluorescein: a pilot study in humans

BACKGROUND/AIMS: Cholyl-lysyl-fluorescein is a fluorescent analogue of the natural bile acid, cholyl glycine. In vivo and in vitro studies showed that this analogue has many biological characteristics similar to cholyl glycine. In this study we analysed cholyl-lysyl-fluorescein plasma clearance in six healthy volunteers as a potential quantitative liver function test. METHODS: The compound in water for injection was administered as an i.v. bolus in the dose of 0.02 mg/kg b.w. RESULTS: The plasma elimination curve showed rapid, intermediate and slow phases of clearance. Half-life (T1/2 time) for the first (t1/2 1st phase), second (t1/2 2nd phase) and third (t1/2 3rd phase) phases of elimination was 1.7+/-0.9 min, 6.7+/-1.6 min and 68+/-17 min, respectively. Ninety-minute plasma retention (% dose/l plasma) was 2.2%. Cholyl-lysyl-fluorescein volume of distribution and residual fluorescence after 60 min were similar to the data obtained by others for natural or radiolabelled bile acids. In five out of six healthy volunteers a 25-fold higher dose of cholyl-lysyl-fluorescein (0.5 mg/kg b.w.) was injected to estimate the safety margins of the compound. This dose was eliminated at a disappearance rate similar to that of the dose of 0.02 mg/kg b.w. and did not cause any adverse reactions. Serum liver tests measured before and after injection did not change significantly. CONCLUSIONS: This study showed that cholyl-lysyl-fluorescein clearance is similar to the clearance of endogenous natural bile acids and may potentially offer a new, dynamic test of liver function.     

Effects of extensive crossfostering on performance of pigs on a farm

OBJECTIVE: To compare mortality and growth rates of pigs subjected to continuous or limited crossfostering. DESIGN: Prospective study. ANIMALS: 80 liters containing 879 pigs. PROCEDURE: In half of the litters, crossfostering was limited to the first 2 days of life. In the other litters, pigs were crossfostered throughout the lactation period to maintain uniform body weights within litters. RESULTS: Restricting crossfostering to the first 2 days of life resulted in a 20% increase in body weight at weaning, compared with crossfostering throughout the nursing period. Mortality rates did not differ between the limited and continuous crossfostering groups. CLINICAL IMPLICATIONS: The emphasis placed on reducing variation of body weights within litters is unwarranted and veterinarians should advise limiting crossfostering to the first 2 days of life. Excessive crossfostering late in the nursing period may be identified by low within-litter SD of mean body weight.     

Identification of functional domains in murine granulocyte-macrophage colony-stimulating factor using monoclonal antibodies to synthetic peptides

Granulocyte-macrophage (GM)-CSF is an important hematopoietic cytokine that regulates proliferation and differentiation of macrophages, neutrophils, and eosinophils. In this study, we generated mAb to five synthetic peptides that correspond to regions along the murine GM-CSF molecule. The ability of anti-peptide mAb to bind to and inhibit biologic activity of murine (m) GM-CSF was determined. mAb with the highest neutralization titers were derived from mice immunized with peptide II, which correspond to amino acids 27 to 38 of mGM-CSF. Immunochemical studies showed that peptide II specifically blocked binding of anti-peptide II mAb to GM-CSF. mAb to two other peptides in the N-terminal half corresponding to residues 7 to 17 and 47 to 58, respectively, of mGM-CSF also inhibited GM-CSF-dependent proliferation and differentiation of murine bone marrow precursors for macrophages and granulocytes. Anti-peptide mAb also inhibited growth of a murine hematopoietic cell line FDCP1 and a murine T cell line HT-2, which was shown to be dependent on GM-CSF for growth in vitro. Biologic activity of both natural and recombinant mGM-CSF was neutralized by anti-peptide mAb. These findings indicate that epitopes in the N-terminal region of mGM-CSF are important for biologic activity, and the epitope defined by peptide II (residues 27 to 38) lies within a particularly important functional domain of the mGM-CSF molecule.     

设计坚固、容错的运动控制反馈系统

本文讨论了一个坚固、容错的运动控制系统的设计，它的反馈通道采用了正交编码器。     

A conserved histidine is essential for glycerolipid acyltransferase catalysis

Sequence analysis of membrane-bound glycerolipid acyltransferases revealed that proteins from the bacterial, plant, and animal kingdoms share a highly conserved domain containing invariant histidine and aspartic acid residues separated by four less conserved residues in an HX4D configuration. We investigated the role of the invariant histidine residue in acyltransferase catalysis by site-directed mutagenesis of two representative members of this family, the sn-glycerol-3-phosphate acyltransferase (PlsB) and the bifunctional 2-acyl-glycerophosphoethanolamine acyltransferase/acyl-acyl carrier protein synthetase (Aas) of Escherichia coli. Both the PlsB[H306A] and Aas[H36A] mutants lacked acyltransferase activity. However, the Aas[H36A] mutant retained significant acyl-acyl carrier protein synthetase activity, illustrating that the lack of acyltransferase activity was specifically associated with the H36A substitution. The invariant aspartic acid residue in the HX4D pattern was also important. The substitution of aspartic acid 311 with glutamic acid in PlsB resulted in an enzyme with significantly reduced catalytic activity. Substitution of an alanine at this position eliminated acyltransferase activity; however, the PlsB[D311A] mutant protein did not assemble into the membrane, indicating that aspartic acid 311 is also important for the proper folding and membrane insertion of the acyltransferases. These data are consistent with a mechanism for glycerolipid acyltransferase catalysis where the invariant histidine functions as a general base to deprotonate the hydroxyl moiety of the acyl acceptor.     

栈溢出的动态检测技术

缓冲区溢出是计算机界的一个古老话题，计算机界和学术界为检测和预防缓冲区溢出投入了很多的精力。但根据CERT（www．cert．org）的数据显示，最近几年中，缓冲区溢出大约占程序错误的50％。另外，根据CERT Ad—visory数据显示，目前仍然有50％左右的安全威胁系来自缓冲区溢出。因此可以说，缓冲区溢出的问题并没有得到根本的解决，而栈溢出是一种最基本的缓冲区溢出。和堆溢出相比，栈溢出更难于监控和危害性更大，因此研究栈溢出具有实际意义。本文对各种栈溢出的检测技术进行了分类和总结，希望能够对栈设计溢出的检测工具提供一些思路。同时，本文介绍了实现栈溢出的动态检测技术中涉及到的各种插装技术，并对各种各样的插装技术进行了总结。     

在频率域中求取薄地层的厚度

在表层地震地质条件单一和激发、接收条件稳定时,利用地震振幅信息可定量地计算薄地层的厚度。但是,实际上地震波很难满足这些条件。因此,本文根据地层模型研究结果,提出了利用频率信息计算薄地层厚度的方法。该方法是采用地震波频谱低频部分的振幅谱值来度量地层厚度,对地震波振幅并没有严格要求。文中还详细讨论了薄互层及不同子波对薄地层厚度计算可能引起的误差问题,讨论结果证明,该方法是可行的。     

Digital Control of a Front-End Loader Linkage

A control system for a front-end loader linkage is specified and developed. Using a microcomputer, the controller is capable of positioning the linkage in either Cartesian or angular motion with the ability to store and recall trajectories. The hardware and software used in a scale model, and the typical response of the linkage are shown.