基于标准单元库的多级函数分解

本文提出在ASIC综合技术中基于标准单元库的多级逻辑函数分解技术。分解过程利用单元库函数真值矩阵及各分解部分用标准单元实现的难易程度、逻辑级数来评价、引导分解得到的多级逻辑易于用标准单元组合实现。使用的标准单元类型具有较大程度的相似性,有利于基于标准单元布局布线软件进一步减少芯片面积。     

Brain abscess and brain tumor: discrimination with in vivo H-1 MR spectroscopy

An experiment is reported examining the relation of implicit grammar learning and series completion tasks to a standard measure of psychometric intelligence, the Wechsler Adult Intelligence Scale-Revised (WAIS-R; D. Wechsler, 1981). The results replicate and extend an earlier study by A. S. Reber, F. F. Walkenfeld, and R. Hernstadt (1991) and provide the following support for the differences between explicit and implicit tasks: (a) The implicit task was less strongly related to Full Scale IQ, and (b) the implicit task appeared to be independent of age. The implicit and explicit tasks exhibited a quite different pattern of relations to the factors known to underlie WAIS-R performance. Although both tasks showed significant links with a Perceptual Organization factor, only the series completion task showed a significant link with the Attention factor.     

Electromyographic activity in a distant muscle during simple voluntary movements: an unexpected hand-eye linkage

PURPOSE: Supraspinal sensorimotor maps contain adjacent representations of the hand and face. These experiments were designed to determine whether interactions between the representations could be detected at the periphery. METHODS: Simultaneous EMG recordings were made from orbicularis oculi and wrist flexor during three conditions, with 50 repetitions each: during exposure to an auditory cue; responding to the auditory cue by wrist flexion; and performing a self-paced wrist flexion in the absence of an auditory cue. RESULTS: In 8 of 10 healthy volunteers, the rectified, averaged EMGs showed small but consistent increases in orbicularis oculi activity during wrist flexion in the two tasks involving that movement, but not in the auditory task alone. CONCLUSION: In one or more of the central sensorimotor maps, voluntary activation of the wrist flexor representation is accompanied by liminal activation of a nearby facial representation which projects to the motoneurons of orbicularis oculi.     

Effects of ethanol on glucose transporter expression in cultured hippocampal neurons

Glucose transport was studied in primary hippocampal neuron cultures exposed to ethanol. Immunofluorescent staining with antibodies against neuron-specific enolase and glial fibrillary acidic protein identified approximately 95% of the cultured cells as neurons. Western blot analysis was conducted with polyclonal antisera to glucose transporter isoforms GLUT1 and GLUT3. As previously seen in astrocytes, GLUT1 protein was regulated by the culture medium glucose content. Exposure to 50 and 100 mM of ethanol for 5 hr induced dose-dependent reductions in GLUT1 and GLUT3 protein. In contrast, GLUT1 mRNA abundance was increased relative to controls under the same conditions. Glucose uptake, measured with the nonmetabolized analog, 2-deoxy-D-glucose, was reduced by 50 and 100 mM of ethanol in four experiments. These results indicate a direct effect of ethanol on neuronal glucose transporter expression, which may play a role in the neurotoxic effects of alcohol.     

Stretched and overwound DNA forms a Pauling-like structure with exposed bases

We investigate structural transitions within a single stretched and supercoiled DNA molecule. With negative supercoiling, for a stretching force >0.3 pN, we observe the coexistence of B-DNA and denatured DNA from sigma approximately -0.015 down to sigma = -1. Surprisingly, for positively supercoiled DNA (sigma > +0.037) stretched by 3 pN, we observe a similar coexistence of B-DNA and a new, highly twisted structure. Experimental data and molecular modeling suggest that this structure has approximately 2.62 bases per turn and an extension 75% larger than B-DNA. This structure has tightly interwound phosphate backbones and exposed bases in common with Pauling's early DNA structure [Pauling, L. & Corey, R. B. (1953), Proc. Natl. Acad. Sci. USA 39, 84-97] and an unusual structure proposed for the Pf1 bacteriophage [Liu, D. J. & Day, L. A. (1994) Science 265, 671-674].     

An investigation of the intra-generic structure of Rothia by pyrolysis mass spectrometry

Some women with benign breast disease eventually develop breast cancer. The mammary gland undergoes tissue remodelling according to hormonal influences, involving a balance between quiescence, proliferation, and mechanisms of cell death. Proliferation and/or apoptotic events could therefore be investigated to help understand the mechanisms of benign lesion formation and identify mastopathies with a poor prognosis. bcl-2 expression was analysed by immunohistochemistry in 75 benign mastopathies. Protein levels were quantitated with an image analyser in various epithelial structures on frozen sections, including adenoses, fibroadenomas, ductal epithelial hyperplasias, cysts, and apparently normal surrounding lobules and ducts. bcl-2 levels were equivalent in apparently normal lobules and ducts, as well as in cysts and ductal hyperplasias. bcl-2 staining was significantly higher in fibroadenomas, known to be of lobular origin [mean = 10.1, quantitative immunochemistry score (QIC) arbitrary units (AU), n = 19], than in normal lobules (mean = 5.1 AU, n = 43, P = 7 x 10(-5). bcl-2 levels in normal lobules and ducts varied according to the menstrual cycle, being higher during the follicular than the luteal phase (P = 1.8 x 10(-2) and P = 1.7 x 10(-2), respectively). This was further supported by a statistical link (P = 5 x 10(-3) between high levels of circulating progesterone and weak bcl-2 staining in lobules and ducts. This progesterone-dependent variation was absent in fibroadenomas. No statistical correlation was found between bcl-2 expression and circulating levels of oestradiol, and follicle-stimulating or luteotrophic hormones. Although these are only preliminary results, they suggest an influence of progesterone on bcl-2 expression which might be lost in fibroadenomas. A hypothesis is proposed concerning the potential involvement of altered regulation of the apoptotic process in the formation of such benign lesions.     

Reconstruction of filtering blebs with free conjunctival autografts

BACKGROUND: Situations arise in which the surgical repair or revision of filtering blebs is either technically impossible or inadequate, and total reconstruction becomes necessary. This is most frequently encountered in eyes that have undergone multiple procedures, resulting in significant bulbar conjunctival scarring and episcleral fibrosis. METHODS: To preserve the pre-existing filtration site, the authors successfully treated five such patients in whom conjunctival scarring adjacent to and surrounding the blebs precluded local revision, by transplanting free conjunctival autografts. Two patients required grafting from the fellow eye. Specific modifications from previously reported conjunctival flap techniques were used to enhance graft healing and continued filtration. RESULTS: Satisfactory intraocular pressure control was maintained in all patients receiving minimal to no anti-glaucomatous medications with an average follow-up of 42.6 months (range, 7-90 months). No patient had a significant decrease in visual acuity or surgical complications. CONCLUSION: Free conjunctival autografting techniques are a useful adjunct in the surgical revision of leaking, failed, or migrating filtration blebs.     

In vivo accuracy of two radiographic systems in the detection of Bj?rk-Shiley convexo-concave heart valve outlet strut single leg separations

OBJECTIVE: Modified cineradiographic systems have been used clinically to detect partially broken outlet struts in normally functioning Bj?rk-Shiley convexo-concave heart valves. Almost all such valves were explanted, presuming that full failure would likely follow. Inasmuch as the clinical setting only rarely permits examination of normally rated valves, the accuracy of radiographic detection cannot be clinically defined. This study uses the clinical radiographic technique in sheep implanted with known-status convexo-concave valves, comparing its accuracy and that of a newly developed, geometric image magnification radiography system. METHODS: Twenty-one sheep with mitral convexo-concave valves were studied on both systems. Five were used for extensive training. When operators were expert with both systems, images of four intact valves and 12 valves with outlet strut single leg separations, along with a seventeenth single leg separation valve used for calibration, were integrated into 112 image sets organized into a balanced incomplete block design for evaluation by eight trained, blinded reviewers. RESULTS: Cineradiography sensitivity was 24% versus 31% for direct image magnification. The odds ratio for detection of single leg separation by direct image magnification versus cineradiography was 2.0 (95% confidence interval, 0.76 to 5.9; p = 0.13). Cineradiography specificity was 93% versus 90% for direct image magnification. Sensitivity and specificity varied markedly by reviewer, with sensitivity ranging from 8% to 55% and specificity from 51% to 100% for the combined technologies. CONCLUSIONS: The data support the need for more intensive training for convexo-concave valve imaging and further investigation of unconventional radiographic technologies. Clinical cineradiography of convexo-concave valves may detect as little as 25% of valves having a single leg separation, underestimating the prevalence of single leg separations and thereby implying more rapid progression to full fracture than is actually the case.