cssi/SciSciGPT-SciSciNet huggingface dataset:
Further Observations on the Usefulness of the Sonographic Murphy Sign in the Evaluation of Suspected Acute Cholecystitis

A positive sonographic Murphy sign, the presence of maximal tenderness elicited over a sonographically localized gallbladder, has been reported to be a helpful adjunctive finding in patients with proven acute cholecystitis who are evaluated with ultrasonography. We evaluated 200 patients with right upper quadrant pain, thought to be acute cholecystitis. Results of ultrasound examinations and subsequent follow-up were tabulated. The sensitivity of the sonographic Murphy sign in acute cholecystitis was 86% with a specificity of 35%, positive predictive value of 43%, and negative predictive value of 82%. The sensitivity of the sonographic findings, including stones, gallbladder wall edema, and pericholecystic fluid collections, was 93%, a specificity of 53%. The combination of the Murphy sign accompanied by gallstones yielded a speci- ficity of 77%. The large number of false positives, and only moderate improvement in specificity when accompanied by gallstones, makes this sign unreliable in separating acute from chronic cholecystitis. 0 1995 John Wiley & Sons, Inc. Indexing Words: Gallbladder . Cholecystitis * Murphy sign There has been great debate in the literature about the diagnostic procedure of choice in acute cholecystitis. Sonography has been favored by some as the first choice in evaluating suspected acute chole~ystitis.'-~ In the proper clinical set- ting, the detection of gallstones is useful in diag- nosing acute cholecystitis, but can fail because many patients with clinically innocuous gall- stones may have right upper quadrant pain which is unrelated to the presence of the ~t0nes.l~~ It has been proposed that the presence of a pos- itive sonographic Murphy sign (SMS), defined as maximal tenderness elicited over a sonographi- cally localized gallbladder, is a useful adjunct in the evaluation of the patient with suspected acute chole~ystitis.~~ ~~~ It was hoped that this sign would help differentiate patients with acute cholecystitis from those with chronic cholecysti- tis.6 We have observed a large number of false- positive SMS in our practice. We therefore under-
Oxidative Stress and Redox-Active Iron in Alzheimer's Disease

Many lines of evidence indicate that oxidative stress is one of the earliest events in the genesis of Alzheimer's disease (AD). Iron is a transition metal capable of generating hydroxyl radicals, the most potent reactive oxygen species. Consequently, a disruption in the metabolism of iron has been postulated to have a role in the pathogenesis of AD. Indeed, both senile plaques and neurofibrillary tangles, the major pathological landmarks of AD, as well as neurons in the earliest stages of the disease, show elevated iron deposition. However, it is clear that the iron bound to lesion-associated proteins such as amyloid-beta and tau plays only a minor, late role in the disease, with the RNA-associated iron found in the neuronal cytoplasm occurring early and being of paramount importance. In this regard, it is probably not surprising that there is significant oxidation of cytoplasmic RNA among the populations of neurons vulnerable to AD. In this review, we consider the role of iron-induced oxidative stress as a key event in AD pathophysiology.
Kinetics of cell deposition under the action of an external field

The kinetics of cellular deposition from a stagnant solution to a surface are studied, taking into account the combined effect of an interaction field between the cells and the surface and of an external field. Since the forces involved in the adhesion of cells to a surface are short ranged, the cells are conveyed to the vicinity of the surface only by the external field. The equations developed are general, in the sense that they are independent of any particular form of the potential energy function, provided that it presents an appreciable potential barrier between the cells and the deposition surface. The characteristic shape of the curve representing the decay of the fraction of cells in solution with time is shown to be affected by the value of Pt*, consisting of the probability per unit time, P, for the escape over the potential barrier, and the sedimentation time, t*. A simple inspection procedure of this curve can disclose the relative significance of the external field and of the potential barrier in the overall kinetics of deposition. In addition, such an inspection can reveal the existence of alterations in the cellular adhesiveness with increasing coverage of the deposition surface. By matching the equation obtained to experimental results, the cellular adhesiveness, in terms of P, and the sedimentation rate (in the case of very slow sedimentation) can be evaluated.
Increased thermotolerance of Clostridium perfringens spores following sublethal heat shock

Abstract Beef gravy samples inoculated with Clostridium perfringens spores were heat shocked at 75 °C for 20 min, and then thermotolerance at 100 °C was assessed using a submerged-coil heating apparatus. Survivors were enumerated on Shahidi Ferguson Perfringens agar. An association of the heat resistance with the origin of the C. perfringens could not be established due to significant variations in the heat resistance among strains. Interestingly, deviations from classical logarithmic linear declines in the log numbers with time were not observed in both control and heat shocked samples. D -values at 100 °C for C. perfringens spores ranged from 15.5 to 21.4 min. Heat shocked spores of 9 out of 10 strains had significantly higher ( p D -values at 100 °C than unstressed spores. Proteins with epitopic and size similarity to Escherichia coli GroEL and Bacillus subtilis small acid-soluble protein, SspC, were present in spores. However, heat shock treated spores did not appear to significantly increase expression of these proteins. Acquired thermotolerance is of substantial practical importance to food processors and should provide useful information for designing thermal treatments to eliminate C. perfringens spores in ready-to-eat foods.
Future directions in cancer prevention.

DETECTION AND CHARACTERIZATION OF RISK FACTORS It is generally acknowledged that environmental factors play a significant role in the causation of cancer (4-9, 19). In principle, therefore, cancer should be preventable to the extent that its causal factors can be identified and either removed from the environment or counteracted (1,4,5,7-9,11,13,14,16-18,20). Recognition of this possibility, in the face of the rising incidence of cancer, challenges us to intensify our efforts to identify the causal factors, to clarify their mechanisms of action, and to formulate appropriate countermeasures. Growing public demand for such efforts is reflected in the recent legislation reauthorizing the U.S. National Cancer Program, which increased the priority given to activities for cancer prevention. Strategies for the detection of carcinogenic risk factors comprise a spectrum of epidemiological and experimental approaches (5,9,12,16,20). Altogether these approaches have thus far implicated some dozens of exogenous agents or exposure conditions as being carcinogenic for humans and some hundreds as carcinogenic for experimental animals (12,15). included are various lifestyle factors (such as ultraviolet radiation, tobacco, and alcohol), dietary factors (such as aflatoxin, safrole, and bracken fern), drugs (such as diethylstibestrol and chlornaphazine), and occupational factors (such as ionizing radiation, vinyl chloride, and asbestos). Also relevant are various preneoplastic conditions predisposing to the development of cancer, such as familial polyposis of the colon, xeroderma pigmentosum, Down’s disease, Fanconi’s anemia, atrophic gastritis, and leukoplakia (Table 1). While proof that a given agent causes cancer in man rests on epidemiologic evidence demonstrating carcinogenic effects in humans themselves, extrapolation from effects in animals can serve to prevent new carcinogens from entering the environment and to prevent continued exposure of humans to otherwise unsuspected risks. Hence, it is the combined use of epidemiologic and laboratory studies, complementing and reinforcing each other, that provides the best foundation for a successful cancer prevention program. Since human beings are exposed throughout life to myriad substances in small amounts and in complex and changing combinations, it is likely that the cancer incidence patterns characteristic for different cultures reflect the interactive effects of prolonged low-level exposure to a multiplicity of carcinogens, cocarcino-
Identification of a model for predicting elastic buckling

Abstract By means of stochastic and deterministic models, we present a system-identification theory for predicting buckling loads of conservative elastic systems from vibration data, thus creating a procedure for non-destructive testing. By means of some illustrative examples (vibrating columns under axial loading) we discuss the problems of existence, uniqueness and sensitivity of the data obtained. We also present a non-linear problem which is associated with the Tsien analogy for the buckling of thin shells.
The strain-controlled creep damage law and its application to the rupture analysis of thick-walled tubes

Abstract A simplified uniaxial strain-controlled creep damage law is deduced with the use of experimental observation from a more complex strain-dependent law. This postulated creep damage law correlates the creep damage, which is interpreted as the density variation in the material, directly with the accumulated creep strain. Continuum mechanical creep rupture analyses are carried out in detail for a plane strain tube problem with temperature gradients present. As rupture propagates from an initial point or surface, a rather complex non-linear moving (free) boundary problem is encountered. A numerical technique is developed to solve the governing differential equations, and the computed results are presented and discussed in detail.
3,3′,5′-Triiodothyronine (Reverse T3) and 3,3′,5-Triiodothyronine)(T3) in Fetal and Adult Sheep: Studies of Metabolic Clearance) Rates, Production Rates, Serum Binding, and Thyroidal Content Relative to Thyroxine

To examine the mechanism(s) responsible for high serum concentration of 3,3',5'-triiodothyronine (reverse T3, rT3) and low serum concentration of 3,3',5-triiodothyronine (T3) in the fetus, we studied metabolic clearance rates (MCR) and production rates (PR) of rT3, T3, and thyroxine (T4) in adult nonpregnant sheep and sheep fetuses in utero. The mean fetal MCR-rT3 was significantly lower than that in adult sheep, and the mean fetal PR-rT3 significantly higher. The mean fetal MCR-T3 was higher than, and the mean fetal PR-T3 similar to that in adult sheep. The mean fetal MCR-T4 and PR-T4 were both significantly higher than the corresponding values in adult sheep. The ratios of mean PR-rT3 to PR-T4 (rT3/T4) were similar in fetal and adult sheep. However, the ratio of mean PR-T3 to PR-T4 (T3/T4) in the fetal sheep was much lower than that in the adult sheep. The low fetal MCR-rT3 was not attributable to high serum binding of rT3. On the basis of the thyroidal content and kinetics of iodothyronines, it was estimated that whereas thyroidal secretion may account for nearly all of serum T3 (or PR-T3) in the fetus and about 50% of serum T3 in adults, it accounts for only about 3% of the serum rT3 (or PR-rT3) in both fetal and adult sheep. The results suggest a) that elevated serum rT3 in the fetus is due to its decreased clearance and increased production by mono-deiodination of T4, and b) that low serum T3 in the fetus is due to its increased clearance and decreased production by mono-deiodination of T4. In addition, on the basis of discordant changes in the production of T3 and rT3 from T4, it appears that there may exist two separate, apparently specific, iodothyronine deiodinating activities--one cleaving the iodine atom at the 5'-position and the other acting in the iodine atom at the 5-position of the T4 molecule; 5'-iodothyronine deiodinating activity is apparently reduced in the fetus.
Effects of solvent on the relative stability of mono and di-aluminium aryloxide complexes of bipyridines: anomalous behavior of [(tBu)2Al(OPh)]2(μ-4,4-bipy)

The temperature dependence of the solution equilibrium constants for [(tBu)2Al(OPh)]2(μ-4,4′-bipy) (1a), [(tBu)2Al(OPh)]2(μ-bipetha) (2a, bipetha = 1,2-bis(4-pyridyl)ethane), and [(tBu)2Al(OPh)]2(μ-bipethe) (3a, bipethe = trans-1,2-bis(4-pyridyl)ethylene) in C6D6 and CDCl3 allow for the determination of ΔH and ΔS for the dissociation of one Al(tBu)2OPh moiety from the bridging ligand, i.e., . For compounds 2a and 3a the ΔH values in C6D6 [99(2) kJ mol−1 (2a) and 109(5) kJ mol−1 (3a)] and CDCl3 [115(5) kJ mol−1 (2a) and 139(7) kJ mol−1 (3a)] were found to be inversely proportional with the dielectric constant of the solvent. In contrast, the ΔH value for 1a in CDCl3 is surprisingly small [14.9(7) kJ mol−1] and does not fit with the trends adopted by the bipetha and bipethe derivatives or the value obtained in C6D6 [110(2) kJ mol−1]. Unlike the other compounds and the C6D6 solutions, the CDCl3 solution of 1a allows for the observation of a second equilibrium , for which the ΔH has been determined [4.5(3) kJ mol−1]. This result suggests that in CDCl3 bonding of the second Al(tBu)2OPh moiety to Al(OPh)(tBu)2(4,4′-bipy) (1b) is stabilized by the presence of the first aluminium, which is counter to ab initio calculations that predicts the aluminium in Al(OPh)(tBu)2(L) should destabilize the Al–N interaction with a second Al(tBu)2OPh group. The BDE for dissociation of both Al(tBu)2OPh moieties from 1a–3a, and the energy of formation of hydrogen bond interactions with CHCl3, has been calculated by ab initio methods, and no unusual effects are inherent in 1a.
Information flows, management styles, and technological innovation

Recent changes in both government and corporate attitudes towards RD (2) a description of the types, sources and channels of stimulus information; (3) a discussion of the role and importance of RD (4) a new model for the idea generation stage which incorporates information flows and a variety of possible managerial and policy actions.
EVALUATION OF ROAD PROJECTS AND PROGRAMS IN DEVELOPING COUNTRIES

Abstract The paper discusses the economic evaluation of road projects in developing countries as currently practiced in World Bank-supported projects. Evaluation of road decisions is necessary whenever there is a budget constraint. A basic principle of equity—but not the only one—is that those who receive the benefit also pay for it, thus designating the budget constraint. This is illustrated with two examples. It is also argued that a well-organized road sector, good road management, customer input, and private sector participation in finance and service delivery affect benefits and costs, and can increase the efficiency and level of service to customers.
A procedure to estimate worst-case air quality in complex terrain☆

Abstract Using a straightforward synoptic climatological analysis scheme, it is shown that the potential for an area to experience air quality degradation due to local sources is highest under polar subtropical highs. With respect to polar highs, the problem is most severe when the sun angle is low and snow covers the ground, and the polar high persists for a long period of time. A simple algorithm is introduced which is designed to estimate worst-case impact in a trapping valley. The potential for the accumulation of air pollution in such valleys due to the persistence of a polar high in a region, is ignored in current regulatory air quality assessments. Trapping valleys and synoptic flow stagnation often occur in wilderness areas. Refined air quality assessments are shown to be possible using a mesoscale meteorological model and a pollution dispersion model. These tools permit quantitative assessments of pollution build-up from local sources as a result of the recirculation of the local air. This tool, along with the synoptic climatological classification scheme, also permits an evaluation of the fractional contribution of long range versus local sources in the air quality degradation in a region. Areas near the center of a polar or subtropical surface high pressure system, for instance, appear to be dominated by local sources, if they exist, whereas in the vicinity of extratropical cyclones, long-range transport is usually much more important.
Path assignment for call routing: an application of tabu search

We describe an implementation of tabu search that solves the path assignment problem, which is the problem of routing video data through an undercapacitated telecommunications network. Two versions of the tabu search were studied. Our results compare very favourably with those from other methods.
Enhanced defect detection capability using combined brightfield/darkfield imaging

Engineering analysis and in-line monitoring common employ either a brightfield TDI imaging or a laser-based darkfield optical approach to defect detection on patterned wafers. Brightfield imaging techniques are commonly used for engineering analysis because of their sensitivity and ability to capture pattern defects, especially in high contrast areas. Laser-based darkfield detection is used because of capture capability on rough deposited layers requiring a good signal to noise ratio. The WF-73X is a laser-based detection system that utilizes a combination of brightfield and darkfield optical configurations. The system offers 0.1 micrometers sensitivity for engineering analysis and 30+ wafer per hour throughput for line monitoring. It combines two propriety technologies employing a five PMT detector configuration.
Low-temperature behavior of potassium and sodium silicate glasses

In a study of the low-temperature anomalies which appear in disordered solids we have measured the specific heat, thermal conductivity, thermal expansion, and dielectric dispersion for a carefully prepared series of (${\mathrm{SiO}}_{2}$${)}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$(${\mathrm{K}}_{2}$O${)}_{\mathrm{x}}$ and (${\mathrm{SiO}}_{2}$${)}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$(${\mathrm{Na}}_{2}$O${)}_{\mathrm{x}}$ glasses. Each sample had a known glass transition temperature ${T}_{g}$, mass density, phonon velocities, covalency, and density and concentration fluctuations. The only significant correlation occurred between the phonon mean free path and the glass-transition temperature. No explicit support was found for any model developed to explain the specific heat and/or thermal conductivity of glasses.
The use of chemical markers in the evaluation of crude oil bioconversion products, technology, and economic analysis

Abstract Experimental data gathered over the past several years show that the interactions of microorganisms with crude oils are variable and depend on the microbial species and the chemical composition of crude oils. Systematic studies of chemical mechanisms by which selected microorganisms react with crude oils have led to the identification of biochemical markers characteristic of the interactions of microbes with oils. These biomarkers belong to several groups of natural products ranging from saturate and polyaromatic hydrocarbons containing heterocyclics to organometallic compounds. Chemical marker analyses indicate that the interaction of microbes with crude oils involves multiple chemical reactions resulting from the biochemical interactions between microbes and oils. Different interactions may influence the efficiency of processes in which single or mixed microbial species are used for the oil treatment and may also suggest possible combinations of biological and chemical technologies. Further, the biochemical conversions of oils can be monitored by these chemical markers, which is particularly useful in the optimization of biochemical processing, cost efficiency, and engineering studies. Recent results from these studies will be discussed.
The interaction of quaternary ammonium compounds with chondroitin sulfate.

Abstract The interaction of a series of mono- and di-quaternary ammonium compounds with chondroitin sulfate A has been studied. Quantitative precipitation of the polysaccharide occurs with cetyl pyridinium chloride and d-tubocurarine. The ratio, moles quaternary bound/mole repeating unit of polysaccharide, is 2 for CPC and 1 for curare. Evidence is presented to show that the rigid curare molecule precipitates by combining simultaneously with both the carboxyl and sulfate groups of the repeating unit of ChSA, rather than causing inter-molecular aggregation. Di-quaternary compounds which do not have a rigid structure fail to precipitate chondroitin sulfate and show only weak interactions in solution.
Calcium-mediated inactivation of calcium current in Paramecium

1. The Ca current seen in response to depolarization was investigated in Paramecium caudatum under voltage clamp. Inactivation of the current was measured with the double pulse method; a fixed test pulse of an amplitude sufficient to evoke maximal inward current was preceded by a conditioning pulse of variable amplitude (0-120 mV).2. The amplitude of the current recorded during the test pulse was related to the potential of the conditioning pulse. Reduction of test pulse current was taken as an index of Ca current inactivation. The current recorded during a test pulse showed a progressive decrease to a minimum as the potential of the conditioning pulse approached +10 to +30 mV. Further increase in conditioning pulse amplitude was accompanied by a progressive restoration of the test pulse current. Conditioning pulses near the calcium equilibrium potential had only a slight inactivating effect on the test pulse current.3. Injection of a mixture of Cs and TEA which blocked late outward current had essentially no effect on the inward current or its inactivation.4. Elevation of external Ca from 0.5 to 5 mM was accompanied by increased inactivation of the test pulse current. The enhanced inactivation of the test pulse current was approximately proportional to the increase in current recorded during the conditioning pulse.5. Following injection of the Ca chelating agent, EGTA, the inactivation of the test pulse current was diminished; in addition, the transient inward current relaxed slightly more slowly, and the transient was followed by a steady net inward current.6. The time course of recovery from inactivation in the double pulse experiment approximated a single exponential having a time constant of 80-110 msec. Injection of EGTA shortened the time constant by as much as 50%.7. It is concluded that interference with the entry of Ca or enhanced removal of intracellular free Ca(2+) interferes with the process of Ca current inactivation, while enhanced entry of Ca promotes the process of inactivation. While the mechanism of inactivation is unknown, arguments are presented that the accumulation of intracellular Ca influences the Ca channel conductance.
Age-related alterations in retinal function.

Age-related visual deficits that occur in the absence of recognized visual disease are frequently observed. Many of the optical factors contributing to these deficits have been delineated, but the contributing neurophysiological alterations have not been clearly defined. This investigation examined age-related variations in the retinal and cortical processing of visual information. Pattern-specific retinal potentials (pattern electroretinogram or PERG in this series) and cortical potentials (VECPs) were recorded from nine young visual normals (20–30 years) and nine healthy elderly individuals (70–80 years). All subjects had best corrected visual acuity of 20/30 or better. Checkerboard patterns (7.5–60 min. checks) were modulated in a counterphase mode (2.0 and 7.5 rps). PERGs and VECPs were simultaneously recorded. Significant age-related alterations in waveform amplitude and latency were observed for both biopotentials. The VECP alterations were largely the result of the reduction in retinal illumination associated with senile miosis, but this factor could not account for most of the observed PERG alterations. These results suggest that neurophysiological changes in the retina may underlie some of the visual deficits observed in healthy elderly adults.
Lagrangian averages, averaged Lagrangians, and the mean effects of fluctuations in fluid dynamics

This paper employs the Lagrangian-averaged Euler- Poincaretheorem to provide a bridge between the gener- alized Lagrangian mean NGLMO equations and the Euler- alpha closure equations. The former NGLMO equations result from an exact theory of nonlinear waves on a La- grangian mean flow and are not closed, while the latter NEuler-alphaO equations are closed via linearization that introduces a length scale a, which Taylor's hypothesis renders constant if it is initially so. The Euler-alpha clo- sure equations with an additional Navier-Stokes viscous dissipation are of interest from the point of view of large eddy simulation and the object of the present work is to show how they relate to a more general theory. To clarify this, we derive them from a small amplitude approxima- tion to the GLM equations, the glm equations, by apply- ing Taylor's hypothesis of frozen-in fluctuations. This derivation from first principles is general enough to in- clude more physics, as we shall illustrate by deriving an alpha model for Lagrangian-averaged ideal magnetohy- drodynamics.
Challenging the Tritope Model of T cell receptor structure-function relationships with classical data on 'super' and 'allo-MHC' antigens.

The response of the immune system to allo-MHC-encoded antigens and Mls ‘superantigens’ has been experimentally analysed in detail, but the data have not been coupled to a theoretical framework. It should therefore be instructive to see how well the newly proposed Tritope Model of TCR structure–function relationships deals with the signalling interactions between the TCR and the above antigens. We will pay heed to William Bateson's admonition, ‘treasure the exceptions’, by showing how a meaningful theory interrogates the data with the same validity that the data interrogate the theory. The concordances, as well as the contradictions, with the Tritope Model are a test of its heuristic value.
Implementing the recommended curriculum in biochemistry & molecular biology at a Large State University: THE TEXAS A&M EXPERIENCE

This article discusses how the biochemistry curriculum at Texas A&M University, a large, state-assisted research university, fulfills the American Society for Biochemistry and Molecular Biology-recommended guidelines. In addition, the research requirement for our degree, changes we are making to the curriculum, and the effect our large service teaching function has on implementing the guidelines are discussed.
Stemflow acid neutralization capacity in a broadleaved deciduous forest: the role of edge effects.

Atmospheric deposition is an important pathway for moisture, nutrient, and pollutant exchange among the atmosphere, forest, and soils. Previous work has shown the importance of proximity to the forest edge to chemical fluxes in throughfall, but far less research has considered stemflow. This study examined the difference in acid neutralization capacity (ANC) of stemflow of nineteen Liriodendron tulipifera L. (yellow poplar) trees between the forest edge and interior in a rural area of northeastern Maryland. We measured ANC directly via potentiometric titration. Stemflow from trees at the forest edge was found to have significantly higher and more variable pH and ANC than in the forest interior (p < 0.01). No mathematical trend between ANC and distance to the forest edge was observed, indicating the importance of individual tree characteristics in stemflow production and chemistry. These results reaffirm the importance of stemflow for acid neutralization by deciduous tree species.
Discovering Web Workload Characteristics through Cluster Analysis

In this paper we present clustering analysis of session-based Web workloads of eight Web servers using the intrasession characteristics (i.e., number of requests per session, session length in time, and bytes transferred per session) as variables. We use K-means algorithm and the Mahalanobis distance, and analyze the heavy-tailed behavior of intra-session characteristics and their correlations for each cluster. Our results show that clustering provides an efficient way to classify tens or hundreds thousands of sessions into several coherent classes that efficiently describe Web workloads. These classes reveal phenomena that cannot be observed when studying the workload as a whole.
A 3, 5-Diaminohexanoate-Decomposing Brevibacterium

An obligately aerobic bacterium that grows on dl-erythro-3, 5-diaminohexanoate as a sole carbon, nitrogen, and energy source was isolated by the enrichment culture method. The organism utilizes only the l isomer by means of an inducible enzyme system. The organism has been tentatively identified as a member of the genus Brevibacterium.
The structure of the products when α-bromoacetoarenones react with 3-(N,N-dimethylamino)propan-1-ol.

Abstract 3-(N,N-Dimethylamino)propan-1-ol readily reacts at room temperature with aryl α-bromoacetophenones to form N-(3-hydroxypropyl)-N,N-dimethyl-N-[2-oxo-2-arylethyl]ammonium bromides in yields up to 89%. Contrary to a previous report (J. Med. Chem. 1966, 9, 211–213), the seven-membered ring hemiketal is not formed. An X-ray structure of the 4-phenylphenyl compound shows the open form. The title reaction yields the hydroxy ketone and not the seven-membered ring hemiketal.
Perioperative β-blocker withdrawal and mortality in vascular surgical patients

Results A total of 140 patients received β-blockers preoperatively. Mortality in the 8 patients who had β-blockers discontinued postoperatively (50%) was significantly greater than in 132 patients who had β-blockers continued (1.5%, odds ratio 65.0, P < .001). The effect of β-blocker discontinuation was unaffected by adjustment by stratification for risk factors (all P ≤ .01), for contraindications to restarting β-blockers (P = .006), and by multivariable analyses adjusting for potential confounders (adjusted odds ratio 17.0, P = .01). β-Blocker discontinuation also was associated with increased cardiovascular mortality (0% vs 29%, P = .005) and postoperative myocardial infarction (odds ratio 17.7, P = .003). Conclusion Discontinuing β-blockers immediately after vascular surgery may increase the risk of postoperative cardiovascular morbidity and mortality. (Am Heart J 2001;141:148-53.)
Microbial Biofilms in the Gut: Visualization by Electron Microscopy and by Acridine Orange Staining

The expression of colonization factors by gut bacteria, the growth rate of gut bacteria, and the rate of plasmid exchange by gut bacteria indicate that biofilms are a normal component of bacterial growth in the large bowel. Further, in vitro experiments demonstrate that growth of normal enteric bacteria in biofilms can be facilitated by secretory IgA (SIgA) and by mucins, 2 major components of the gut milieu. However, biofilms have not been previously observed in the normal gut. In this study, bacterial colonies characteristic of biofilms were observed by electron microscopy in normal rat, baboon, and human gut by electron microscopy. Confirming these results, acridine orange staining of flash-frozen tissues revealed biofilms in the mucus lining along normal gut epithelium. Immunofluorescenct microscopy supported this finding and demonstrated an association between IgA and the biofilms. These findings provide direct evidence that biofilms are present and may play an important role in the commensal relationship between enteric bacteria and their hosts. Hematoxylin and eosin staining of formalin-fixed tissues resulted in dissociation of the luminal contents from the epithelium, suggesting that the association between biofilms and the gut epithelium is sensitive to some conditions used to preserve tissue for histologic evaluation.
Herpesvirus quiescence (QIF) in neuronal cells VI: Correlative analysis demonstrates usefulness of QIF-PC12 cells to examine HSV-1 latency, reactivation and genes implicated in its regulation.

Purpose. To compare the usefulness of the in vitro quiescently infected (QIF)-PC12 cell model with the in vivo rabbit eye model of latency for the study of herpes simplex virus (HSV) genes implicated in reactivation from latency. Methods. HSV-1 strains 17+/pR20.5/5 and 17+/pR20.5/ 5/LAT, that were previously constructed by insertion of genes encoding beta-galactosidase, green fluorescent protein (GFP) or the latency associated transcript (LAT) open reading frame in the U S 5 region, were used to examine viral growth and inducible reactivation in the two models. Results. 17+/pR20.5/5 exhibited diminished reactivation phenotype when compared with wild type 17+ in neuronal cells (i.e., QIF-PC12 cell model) and the rabbit eye model of latency. 17+/pR20.5/5/LAT, which contains the deregulated LAT gene, reactivated at wild type levels. Analysis of growth in neurally differentiated (ND)-PC12 cells demonstrated a low proportion of QIF cells expressed virus-encoded signals during the quiescent infection and a dire...
Transitive closure on the cell broadband engine: A study on self-scheduling in a multicore processor

In this paper, we present a mappingmethodology and optimizations for solving transitive closure on the Cell multicore processor. Using our approach, it is possible to achieve near peak performance for transitive closure on the Cell processor. We first parallelize the Standard Floyd Warshall algorithm and show through analysis and experimental results that data communication is a bottleneck for performance and scalability. We parallelize a cache optimized version of Floyd Warshall algorithm to remove the memory bottleneck. As is the case with several scientific computing and industrial applications on a multicore processor, synchronization and scheduling of the cores plays a crucial role in determining the performance of this algorithm. We define a self-scheduling mechanism for the cores of a multicore processor and design a self-scheduler for Blocked Floyd Warshall algorithm on the Cell multicore processor to remove the scheduling bottleneck. We also present optimizations in scheduling order to remove synchronization points. Our implementations achieved up to 78GFLOPS.
Intestinal anastomotic injury alters spatially defined microbiome composition and function

When diseased intestine (i.e., from colon cancer, diverticulitis) requires resection, its reconnection (termed anastomosis) can be complicated by non-healing of the newly joined intestine resulting in spillage of intestinal contents into the abdominal cavity (termed anastomotic leakage). While it is suspected that the intestinal microbiota have the capacity to both accelerate and complicate anastomotic healing, the associated genotypes and functions have not been characterized. Using 16S rRNA amplicon sequencing of samples collected on the day of surgery (postoperative day 0 (POD0)) and the 6th day following surgery (postoperative day 0 (POD6)), we analyzed the changes in luminal versus tissue-associated microbiota at anastomotic sites created in the colon of rats. Results indicated that anastomotic injury induced significant changes in the anastomotic tissue-associated microbiota with minimal differences in the luminal microbiota. The most striking difference was a 500-fold and 200-fold increase in the relative abundance of Enterococcus and Escherichia/Shigella, respectively. Functional profiling predicted the predominance of bacterial virulence-associated pathways in post-anastomotic tissues, including production of hemolysin, cytolethal toxins, fimbriae, invasins, cytotoxic necrotizing factors, and coccolysin. Taken together, our results suggest that compositional and functional changes accompany anastomotic tissues and may potentially accelerate or complicate anastomotic healing.
Web-based tutoring in power engineering

This paper deals with the application of web-based technologies to power engineering education in an interactive student/mentor environment. The modern teaching/learning concepts and new technologies to support these concepts have been developed. This project incorporates web-based tools, including Internet, videoconferencing, and educational intelligent system modules for power engineering education. Different student learning styles are adapted for power engineering applications. The proposed interactive learning environment allows the mentor and students to best utilize the facilities for effective teaching and learning.
Stress sensing in plants by an ER stress sensor/transducer, bZIP28

Two classes of ER stress sensors are known in plants, membrane associated bZIP transcription factors and RNA splicing factors. ER stress occurs under adverse environmental conditions and results from the accumulation of misfolded or unfolded proteins in the ER lumen. One of the membrane-associated transcription factors activated by heat and ER stress agents is bZIP28. In its inactive form, bZIP28 is a type II protein with a single pass transmembrane domain, residing in the ER. bZIP28’s N-terminus, containing a transcriptional activation domain, is oriented towards the cytoplasm and its C-terminal tail is inserted into the ER lumen. In response to stress, bZIP28 exits the ER and moves to the Golgi where it is proteolytically processed, liberating its cytosolic component which relocates to the nucleus to upregulate stress-response genes. bZIP28 is thought to sense stress through its interaction with the major ER chaperone, BIP. BiP binds to bZIP28’s lumenal domain under unstressed conditions and retains it in the ER. BIP binds to the intrinsically disordered regions on bZIP28’s lumen-facing tail. A truncated form of bZIP28, without its C-terminal tail is not retained in the ER but migrates constitutively to the nucleus. Upon stress, BiP releases bZIP28 allowing it to exit the ER. One model to account for the release of bZIP28 by BiP is that BiP is competed away from bZIP28 by the accumulation of misfolded proteins in the ER. However, other forces such as changes in energy charge levels, redox conditions or interaction with DNAJ proteins may also promote release of bZIP28 from BiP. Movement of bZIP28 from the ER to the Golgi is assisted by the interaction of elements of the COPII machinery with the cytoplasmic domain of bZIP28. Thus, the mobilization of bZIP28 in response to stress involves the dissociation of factors that retain it in the ER and the association of factors that mediate its further organelle-to-organelle movement.
Inflammatory pathogenesis of prostate cancer and celecoxib.

proliferative inflammatory atrophy (PIA), a putative preneoplastic lesion, and described the immunophenotype of the inflammatory stroma that invariably accompanied PIA as largely consisting of CD3 T cells, but also CD20 B lymphocytes and CD-68 macrophages. Luo et al 2 have reported that RANKL-expressing T lymphocytes and macrophages in the inflammatory microenvironment may activate IKK in prostate cancer cells, repressing maspin expression and thereby promoting metastatic behavior of prostate cancer cells, largelyunlinkedfromproliferativebehavior.Inthisimportantpreoperative study of the anti-inflammatory agent celecoxib in low and intermediate-gradeadenocarcinomaoftheprostatebyAntonarakiset al, 3 tissueeffectsofcelecoxibcouldnotbedetectedwithbiomarkersof oxidative damage, prostaglandin concentrations, COX-1 and 2, and Ki-67 expression. Given that peripheral blood lymphocytes and monocyteslikelytrafficcontinuallythroughtheinflammatorymicroenvironment of the preneoplastic and neoplastic prostate, one questions whether biomarkers of celecoxib effect 4 could be detected in the
Microstructure and Elevated Temperature Properties of a Refractory TaNbHfZrTi Alloy

Compression properties of a refractory multi-component alloy, Ta20Nb20Hf20Zr20Ti20, were determined in the temperature range of 296–1473 K and strain rate range of 10−1–10−5 s−1. The properties were correlated with the microstructure developed during compression testing. The alloy was produced by vacuum arc melting, and it was hot isostatically pressed (HIPd) and homogenized at 1473 K for 24 h prior to testing. It had a single-phase body-centered cubic structure with the lattice parameter a = 340.4 pm. The grain size was in the range of 100–200 μm. During compression at a strain rate of έ = 10−3 s−1, the alloy had the yield strength of 929 MPa at 296 K, 790 MPa at 673 K, 675 MPa at 873 K, 535 MPa at 1073 K, 295 MPa at 1273 K and 92 MPa at 1473 K. Continuous strain hardening and good ductility (e ≥ 50%) were observed in the temperature range from 296 to 873 K. Deformation at T = 1073 K and έ ≥ 10−3 s−1 was accompanied by intergranular cracking and cavitation, which was explained by insufficient dislocation and diffusion mobility to accommodate grain boundary sliding activated at this temperature. The intergranular cracking and cavitation disappeared with an increase in the deformation temperature to 1273 and 1473 K or a decrease in the strain rate to ~10−5 s−1. At these high temperatures and/or low-strain rates the alloy deformed homogeneously and showed steady-state flow at a nearly constant flow stress. Partial dynamic recrystallization, leading to formation of fine equiaxed grains near grain boundaries, was observed in the specimens deformed at 1073 and 1273 K and completed dynamic recrystallization was observed at 1473 K.
Insertional mutagenesis and illegitimate recombination in mycobacteria

Mycobacteria, particularly Mycobacterium tuberculosis, Mycobacterium leprae, and Mycobacterium avium, are major pathogens of man. Although insertional mutagenesis has been an invaluable genetic tool for analyzing the mechanisms of microbial pathogenesis, it has not yet been possible to apply it to the mycobacteria. To overcome intrinsic difficulties in directly manipulating the genetics of slow-growing mycobacteria, including M. tuberculosis and bacille Calmette-Guerin (BCG) vaccine strains, we developed a system for random shuttle mutagenesis. A genomic library of Mycobacterium smegmatis was subjected to transposon mutagenesis with Tn5 seq1, a derivative of Tn5, in Escherichia coli and these transposon-containing recombinant plasmids were reintroduced into mycobacterial chromosomes by homologous recombination. This system has allowed us to isolate several random auxotrophic mutants of M. smegmatis. To extend this strategy to M. tuberculosis and BCG, targeted mutagenesis was performed using a cloned BCG methionine gene that was subjected to Tn5 seq1 mutagenesis in E. coli and reintroduced into the mycobacteria. Surprisingly for prokaryotes, both BCG and M. tuberculosis were found to incorporate linear DNA fragments into illegitimate sites throughout the mycobacterial genomes at a frequency of 10(-5) to 10(-4) relative to the number of transformants obtained with autonomously replicating vectors. Thus the efficient illegitimate recombination of linear DNA fragments provides the basis for an insertional mutagenesis system for M. tuberculosis and BCG.
Juvenile granulosa cell ovarian tumor: a case report and review of literature.

Abstract Background Juvenile granulosa cell tumors (JGCT) are rare ovarian tumors that frequently present with precocious puberty. Presentation in infants less than a year of age is also rare. Case We describe a 10-month-old infant who presented with both premature thelarche and adrenarche due to JGCT. Laboratory evaluation revealed classic elevation of estradiol and inhibin B, and less classic elevation of total and free testosterone. Oophorectomy and staging resulted in a diagnosis of Stage IA JGCT. Summary and Conclusion Survival rates are >95% among patients diagnosed under 10 years of age. Tumor recurrence is rare but can occur as late as 48 months. Therefore, tumor surveillance is warranted for patients with even a Stage IA JGCT and involves monitoring serial inhibin B levels along with intermittent imaging.
Risk-adapted strategies for the treatment of Hodgkin lymphoma.

Introduction: Over the past several decades, Hodgkin lymphoma (HL) has become a highly treatable lymphoid malignancy with excellent response rates and long-term disease-free survival. Late-toxicities, however, continue to be an area of significant concern. Recent studies have evaluated novel approaches to limit long-term toxicity without adversely impacting short-term survival. While early or interim PET scan has been correlated with PFS and OS in HL, the modification of therapy based on interim PET (response-adapted therapy) has been evaluated in retrospective and prospective cohorts. This paper will review evidence for the role of response-adapted therapy in HL.Areas covered: Data from completed and ongoing retrospective and prospective cohorts of HL patients were reviewed utilizing pubmed and clinicaltrials.org and pertinent studies culled to compile this review article.Expert opinion: While response-adapted therapy represents a promising area of research which may ultimately become standard-of-care, c...
RNA recognition by the DNA end-binding Ku heterodimer

Most nucleic acid-binding proteins selectively bind either DNA or RNA, but not both nucleic acids. The Saccharomyces cerevisiae Ku heterodimer is unusual in that it has two very different biologically relevant binding modes: (1) Ku is a sequence-nonspecific double-stranded DNA end-binding protein with prominent roles in nonhomologous end-joining and telomeric capping, and (2) Ku associates with a specific stem-loop of TLC1, the RNA subunit of budding yeast telomerase, and is necessary for proper nuclear localization of this ribonucleoprotein enzyme. TLC1 RNA-binding and dsDNA-binding are mutually exclusive, so they may be mediated by the same site on Ku. Although dsDNA binding by Ku is well studied, much less is known about what features of an RNA hairpin enable specific recognition by Ku. To address this question, we localized the Ku-binding site of the TLC1 hairpin with single-nucleotide resolution using phosphorothioate footprinting, used chemical modification to identify an unpredicted motif within the hairpin secondary structure, and carried out mutagenesis of the stem-loop to ascertain the critical elements within the RNA that permit Ku binding. Finally, we provide evidence that the Ku-binding site is present in additional budding yeast telomerase RNAs and discuss the possibility that RNA binding is a conserved function of the Ku heterodimer.
Vpr Cytopathicity Independent of G2/M Cell Cycle Arrest in Human Immunodeficiency Virus Type 1-Infected CD4+ T Cells

The mechanism of CD4 + T-cell depletion in human immunodeficiency virus type 1 (HIV-1)-infected individuals remains unknown, although mounting evidence suggests that direct viral cytopathicity contributes to this loss. The HIV-1 Vpr accessory protein causes cell death and arrests cells in the G 2 /M phase; however, the molecular mechanism underlying these properties is not clear. Mutation of hydrophobic residues on the surface of its third alpha-helix disrupted Vpr toxicity, G 2 /M arrest induction, nuclear localization, and self-association, implicating this region in multiple Vpr functions. Cytopathicity by virion-delivered mutant Vpr protein correlated with G 2 /M arrest induction but not nuclear localization or self-association. However, infection with whole virus encoding these Vpr mutants did not abrogate HIV-1-induced cell killing. Rather, mutant Vpr proteins that are impaired for G 2 /M block still prevented infected cell proliferation, and this property correlated with the death of infected cells. Chemical agents that inhibit infected cells from entering G 2 /M also did not reduce HIV-1 cytopathicity. Combined, these data implicate Vpr in HIV-1 killing through a mechanism involving inhibiting cell division but not necessarily in G 2 /M. Thus, the hydrophobic region of the third alpha-helix of Vpr is crucial for mediating G 2 /M arrest, nuclear localization, and self-association but dispensable for HIV-1 cytopathicity due to residual cell proliferation blockade mediated by a separate region of the protein.