Serum HIV-1 RNA levels and time to development of AIDS in the Multicenter Hemophilia Cohort Study

Normal women produce small amounts of active androgens. When androgen levels are elevated, such as for example in the polycystic ovary syndrome, this is followed by the development of male physical characteristics and muscle mass, structure and function as well as android adipose tissue distribution and function. Psychological features and stress reactions also seem similar to those of men. Such women have an increased risk of developing hypertension, non-insulin-dependent diabetes mellitus and cardiovascular disease. Recent data have shown that these physical, and psychological characteristics, as well as risk of ill health, are also found in the population of women selected at random. Women in the lowest quintiles of levels of sex-hormone-binding globulin--an indicator inversely related to active androgens--are at risk of developing hypertension, non-insulin-dependent diabetes mellitus and cardiovascular mortality. The mechanism probably includes muscular insulin resistance, following a relative androgen excess. It is thus apparent that androgens, even within the highest levels of the nonselected population of women, are powerful predictors of serious disease development. The population at risk might be as large as about 20% of middle-aged women. This is an area of female disease risk which requires more attention in screening and intervention procedures.     

Oxidation of SiCf/SiC‐HfB2 Composites under Laser Heating

Ceramic matrix composites with Sylramic^TM and CG Nicalon^TM SiC fibers and SiC‐HfB₂ matrices derived from a combination of polymer‐derived SiC ceramic and HfB₂ particulate slurries were prepared. The composites were tested for oxidation resistance by laser heating at 2 MW/m² to achieve temperatures near 1600°C. The oxidation resistance was compared between uncoated CG Nicalon^TM and BN‐coated Sylramic^TM fiber‐based composites. Oxidation resulted in precipitated nano‐sized HfO₂ independent of the fibers and fiber coatings.     

External and internal electrostatic potentials of cholinesterase models

The electrostatic potentials for the three-dimensional structures of cholinesterases from various species were calculated, using the Delphi algorithm, on the basis of the Poisson–Boltzmann equation. We used structures for Torpedo californica and mouse acetylcholinesterase, and built homology models of the human, Bungarus fasciatus, and Drosophila melanogaster acetylcholinesterases and human butyrylcholinesterase. All these structures reveal a negative external surface potential, in the area around the entrance to the active-site gorge, that becomes more negative as the rim of the gorge is approached. Moreover, in all cases, the potential becomes increasingly more negative along the central axis running down the gorge, and is largest at the base of the gorge, near the active site. Ten key acidic residues conserved in the sequence alignments of AChE from various species, both in the surface area near the entrance of the active-site gorge and at its base, appear to be primarily responsible for these potentials. The potentials are highly correlated among the structures examined, down to sequence identities as low as 35%. This indicates that they are a conserved property of the cholinesterase family, could serve to attract the positively charged substrate into and down the gorge to the active site, and may play other roles important for cholinesterase function.     

Personalized identification of abdominal wall hernia meshes on computed tomography

An abdominal wall hernia is a protrusion of the intestine through an opening or area of weakness in the abdominal wall. Correct pre-operative identification of abdominal wall hernia meshes could help surgeons adjust the surgical plan to meet the expected difficulty and morbidity of operating through or removing the previous mesh. First, we present herein for the first time the application of image analysis for automated identification of hernia meshes. Second, we discuss the novel development of a new entropy-based image texture feature using geostatistics and indicator kriging. Third, we seek to enhance the hernia mesh identification by combining the new texture feature with the gray-level co-occurrence matrix feature of the image. The two features can characterize complementary information of anatomic details of the abdominal hernia wall and its mesh on computed tomography. Experimental results have demonstrated the effectiveness of the proposed study. The new computational tool has potential for personalized mesh identification which can assist surgeons in the diagnosis and repair of complex abdominal wall hernias.     

Support for the discharge model of emotion: A reply to Zuckerman.

Responds to criticisms by M. Zuckerman (see record 1984-11616-001) of a study by the present author et al (see record 1983-05644-001) which reported evidence in support of the discharge model of the relation between facial expressivity and physiological reactivity. It is argued that Zuckerman's challenge to the Notarius et al study and conclusions is unfounded for 2 reasons: (a) Zuckerman's critique contains several interpretative errors of the Notarius et al study, and (b) subsequent data analysis, recommended by Zuckerman, overwhelmingly supports the original interpretation of the study. (2 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The breakdown into nitric oxide of compounds potentially derived from nitrite in a biological matrix

Summary N-Nitroso compounds can be determined using a chemiluminescence analyzer by means of the nitric oxide liberated as a volatile product of their denitrosation using hydrogen bromide [1, 2]. Much of the nitrite present in or added to a food matrix can be lost even during storage in a refrigerated condition and thus the possibility arises of its conversion into compounds other than nitrosamines and nitrosamides which could also give rise to nitric oxide under, for instance, thermal degradation. Among compounds potentially formed from nitrite that have been studied in relation to their breakdown to nitric oxide have been included an alkyl nitrate, an alkyl nitrite, an amine oxide, an azoxy compound, a nitramine, a nitro guanidine, a nitrolic acid, a nitrone, an oxime, a pseudonitrole, a pseudonitrosite, a thionitrite, a thionitrate as well as C-nitro and C-nitroso compounds. Only in the case of the nitrolic acid and the thionitrate was it likely that interference with the determination of N-nitroso compounds could occur to any considerable extent.

---

Abspaltung von NO aus möglichen Folgeprodukten von Nitrit in einer biologischen Matrix

Zusammenfassung N-Nitrosoverbindungen können durch die Chemiluminiscenz-Methode über das Stickoxid bestimmt werden, das durch Denitrosierung mit HBr als flüchtiges Produkt entsteht. Ein großer Teil des Nitrits, das in Lebensmitteln enthalten ist oder zugesetzt wurde kann auch bei Kühllagerung bereits verloren gehen und in andere Produkte als Nitrosamine oder Nitrosamide umgewandelt werden, die bei der thermischen Zersetzung zur Bildung von NO Anlaß geben. Unter den mit Nitrit entstehenden Verbindungen, die zu einer Abspaltung von NO führen könnten, wurden näher untersucht ein Alkylnitrat, ein Alkylnitrit, ein Aminoxyd, eine Azoxy-Verbindung, ein Nitramin, ein Nitroguanidin, eine Nitrolsäure, ein Nitron, ein Oxim, ein Pseudonitrol, ein Pseudonitrosit, ein Thionitrit, sowie C-Nitro- und C-Nitroso-Verbindungen. Nur bei der Nitrolsäure und bei Thionitrat könnte eine Störung der Bestimmung von N-Nitrosoverbindungen über die NO-Abspaltung in beachtlichem Umfang eintreten.

     

Distributed Job Scheduling in Rings

We give a distributed approximation algorithm for job scheduling in a ring architecture. In contrast to many other parallel scheduling models, the model we consider captures the influence of the underlying communications network by specifying that task migration from one processor to another takes time proportional to the distance between those two processors in the network. As a result, our algorithm must balance computational load and communication time. The algorithm is simple, requires no global control, and yields schedules of length at most 4.22 times optimal. We also give a lower bound on the performance of any distributed algorithm and the results of simulation experiments which suggest better performance than does our worst-case analysis.     

Development of a Weather Forecasting Code: A Case Study

Computational science is increasingly supporting advances in scientific and engineering knowledge. The unique constraints of these types of projects result in a development process that differs from the process more traditional information technology projects use. This article reports the results of the sixth case study conducted under the support of the Darpa High Productivity Computing Systems Program. The case study aimed to investigate the technical challenges of code development in this environment, understand the use of development tools, and document the findings as concrete lessons learned for other developers' benefit. The project studied here is a major component of a weather forecasting system of systems. It includes complex behavior and interaction of several individual physical systems (such as the atmosphere and the ocean). This article describes the development of the code and presents important lessons learned.