cssi/SciSciGPT-SciSciNet huggingface dataset:
An improved minimum spanning tree stereo matching algorithm

The minimum spanning tree stereo matching algorithm only takes one channel of R, G, B channels into account, ignoring the effect of the other two channels on the final edge weight in color image. This paper proposes an improved minimum spanning tree stereo matching algorithm, which calculates the weighted euclidean distance using a three-channel approach, and combines three-channel edge weight. This algorithm has been tested on Tsukuba, Venus, Teddy, Cones image. Simulation results show that the improved algorithm enhances the robustness of edge weight function and the connectivity of minimum spanning tree. It not only improves stereo matching accuracy, but also increases computational speed.
Search for the violation of time-reversal invariance in K/sup 0//sub mu3/ decays

The transverse polarization of muons from the decay ${K}_{L}^{0}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\mu}}^{+}{\ensuremath{\nu}}_{\ensuremath{\mu}}$ has been recently measured at Brookhaven National Laboratory. A cylindrically symmetric detector was employed with scintillation-counter hodoscopes detecting the charged decay products of the in-flight kaon decay and determining the orientation of the decay plane in the laboratory. Muons were brought to rest in an aluminum polarimeter where they precessed in 60-G magnetic field. The muon polarization was determined from the asymmetric emission of the positron in the muon decay (${\ensuremath{\mu}}^{+}\ensuremath{\rightarrow}{e}^{+}{\ensuremath{\nu}}_{e}{\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}}$). With 12\ifmmode\times\else\texttimes\fi{}${10}^{6}$ events collected the mean values measured for the two components of transverse polarization are ${P}_{n}^{\mathrm{lab}}=0.0017\ifmmode\pm\else\textpm\fi{}0.0056$ for the component normal to the decay plane and ${P}_{t}^{\mathrm{lab}}=0.417\ifmmode\pm\else\textpm\fi{}0.063$ for the component in the decay plane. For $\mathrm{Im}\ensuremath{\xi}$, where $\ensuremath{\xi}$ is the ratio of form factors describing ${K}_{\ensuremath{\mu}3}$ decay, we have deduced a value of 0.009\ifmmode\pm\else\textpm\fi{}0.030 which is not significantly different from the value 0.008, expected if time-reversal invariance is valid. We deduce that the average value of the ratio of the normal to transverse components of muon polarization in the kaon rest frame is given by ${〈\frac{{P}_{n}}{{P}_{t}}〉}^{\mathrm{c}.\mathrm{m}.}=0.005\ifmmode\pm\else\textpm\fi{}0.015$.
The Central Role of Reconnection in Space Plasma Phenomena Targeted by the Magnetospheric Multiscale Mission

Abstract The Magnetospheric Multiscale Mission, which consists of four identically instrumented spacecraft flying in close formation, will allow the first extensive characterization of the 3D structure and dynamic variations of the magnetosphere on scales down to electron inertial length. By targeting the magnetopause and magnetotail, two regions already known to provide observations crucial to understanding the reconnection process, the mission will determine the spatial and temporal scales of basic plasma processes.
Alternative pre-mRNA splicing and neuronal function.

The protein output of a gene is often regulated by splicing the primary RNA transcript into multiple mRNAs that differ in their coding exon sequences. These alternative splicing patterns are found in all kinds of genes and tissues. However, in the nervous system, proteins involved in two processes show particularly high levels of molecular diversity created by alternative splicing. These are proteins that determine the formation of neuronal connections during development and proteins that mediate cell excitation. Although some systems of splicing are highly complex, work on simpler model systems has started to identify the molecular components that determine these splicing switches. This review describes how alternative splicing is central to the control of neuronal function, and what is currently known about its mechanisms of regulation. How errors in splicing might contribute to diseases of the nervous system is also discussed.
Intelligent internetted sensor management systems for tactical aircraft

The authors propose a design of an internetted sensor management system (ISMS) and discuss the advantages and disadvantages of using such a system. Quantifiable measures of performance for assessing the benefits of internetted sensor management are defined. The effects of internetted sensor management and cooperative tactics on the intraflight data link requirements are discussed. >
Mechanisms of vascular graft thrombosis: Role of altered canine platelet sensitivity to thromboxane

Abstract Using the standard turbidimetric method of platelet aggregation and quantitation of platelet secretion with 14 C-Serotonin, we have examined the responsiveness of the platelets of mongrel dogs to arachidonic acid (AA), and the thromboxane agonist U46619 in the presence and absence of a subthreshold concentration of epinephrine. In response to stimulation with 750 μM AA, the platelets of 18 dogs produced irreversible aggregation (Group I), the platelets of 22 dogs showed, at most, reversible aggregation (Group II), while the platelets of 8 dogs demonstrated no aggregatory response (Group III). In the presence of AA and a subthreshold concentration of epinephrine (0.5 μM), the platelets of all three groups demonstrated enhanced aggregatory and secretory responses although the extent of 14 C-Serotonin secretion differed significantly between all three groups. These in vitro differences in platelet aggregation correlate with the in vivo deposition of platelets onto synthetic vascular grafts and the maintenance of graft patency. When stimulated with 0.5 μM U46619 and a subthreshold concentration of epinephrine, the platelets of 97% Group I dogs and 75% of Group II dogs exhibited irreversible aggregation, while the platelets of all Group III dogs showed only reversible aggregation. In addition, significant differences in the extent of 14 C-Serotonin secretion to this combination of agonists were observed between groups. Further examination of the specific effects of U46619 on canine platelets revealed that although the aggregatory and secretory responses to U46619 vary between the different canine platelet populations, the threshold concentration of U46619 required to produce platelet shape change is identical among all groups. Quantitation of the stable metabolite of AA produced via the cyclooxygenase pathway, thromboxane B 2 (TxB 2 ), revealed no significant differences in the production of TxB 2 by the platelets of these different populations upon stimulation with AA. Our results suggest that the mechanisms underlying the differences in responsiveness of canine platelets to AA, are likely due to differences in sensitivity of canine platelets to TxA 2 , and may be localized to the mechanism responsible for mediating platelet aggregation and secretion in response to TxA 2 .
Distribution of 5-methylcytosine in the DNA of somatic and germline cells from bovine tissues

Genomic DNA of calf thymus contains 1.5 times as much 5-methylcytosine as similar sperm DNA, but the major EcoRI repeat fragment from satellite I of thymus contains ten times as much 5-methylcytosine as the corresponding fragment from sperm DNA. Restriction enzyme analyses of the total DNA and the satellite I fragment show that three HpaII sites in the fragment are completely unmethylated in sperm but fully methylated in thymus DNA. Under-methylation of many sites in the satellite DNAs can probably account for the lower level of methylation of sperm DNA rather than hemimethylation as previously suggested. These results are also discussed in relation to maintenance and de novo (initiation-type) methylases.
The Teaching of Ethics in the American Undergraduate Curriculum, 1876–1976

This article is an attempt to look at main developments and issues in the teaching of ethics to undergraduates during the past century. Although I had suspected as much, it was not until I was well under way in working on the piece that I began to realize the extent to which a look at the teaching of ethics provides, as it were, a central window on the whole of American higher education. The teaching of ethics has been uniquely and inseparably connected with the most important issues of modern higher education, issues involving the curriculum, institutionalization, professionalization, epistemology, the “two cultures” split, the community—indeed, the very purposes of higher education. It is with this larger perspective in view that I have sought to understand the place and problems of the teaching of ethics, not only with respect to ethics courses as such, but also in the larger curriculum. Even as concern with the teaching of ethics has time and again flagged or even disappeared at one point in American higher education, it has without fail, and almost immediately, reappeared at another; for the issues with which it deals have been those integral to the entire enterprise.
Emergency UHF Radio for Gemini Astronauts

This paper describes a UHF Beacon/ Transceiver which will be part of the Gemini astronauts' survival kit. The all solid-state transmitter provides a minimum of 2 watts average power for 24 hours in the beacon mode and 1.2 watts of average power in the voice mode. The dynamic range of the double conversion superheterodyne receiver permits the radio to communicate with search aircraft at ranges from 50 feet to 25 miles.
Inhibition of human immunodeficiency virus type 1 replication and cytopathicity by synthetic soluble catecholamine melanins in vitro

Synthetic soluble melanins were synthesized by spontaneous oxidation of L-dopamine, norepinephrine or 5-hydroxytryptamine (serotonin) in weak alkaline solution. These three melanins inhibited infection of human CD4+ lymphoblastoid cells (MT-2) by cell-free human immunodeficiency virus type 1 (HIV-1), without cell toxicity, at concentrations of 0.15-10 micrograms/ml. Also, syncytium formation and resulting cytopathic effects when uninfected cells were mixed with chronic HIV-1-infected cells were blocked by these melanins. Antisyncytial activity was greater when infected cells were preincubated with melanin than when uninfected cells were preincubated with melanin, thus suggesting that interaction of melanin with viral proteins is an important aspect of the antiviral mechanism. These results make synthetic soluble melanins interesting candidates for further study as possible anti-HIV-1 therapeutics.
6-Oxodendrolasin, 6-hydroxydendrolasin, 9-oxofarnesol and 9-hydroxyfarnesol, stress metabolites of the sweet potato

Abstract Four sesquiterpene stress metabolites, 6-oxodendrolasin, 6-hydroxydendrolasin, 9-oxofarnesol, and 9-hydroxyfarnesol have been isolated from mercuric chloride-treated sweet potatoes. The metabolites have been synthesized and feeding studies have been carried out to determine the extent of incorporation of 14 C-labelled 6-oxodendrolasin and 9-hydroxyfarnesol into ipomeamarone.
Early Moravian Settlements in America

In Pennsylvania, foremost of the primitive commonwealths of the United States in presenting conditions favorable to many kinds of undertakings, Moravians effected their first permanent settlements in America. William Perm had contemplated as his “holy experiment” a Quaker colony within which all religions should be tolerated. The scheme of peace with freedom, however, very soon produced a condition of turmoil. At the outset, co-religionists of the founder came to Pennsylvania in such numbers as to give them preponderance in the affairs of the colony. Then, in response to the generous offers of Penn, that Teutonic immigration began which threatened, at one time, to make Perm's colony alien from his countrymen. These emigrants to the colony did not come from those parts of Europe where the Christians were all of one way of worshipping. They were persecuted refugees of all sorts. For the most part, they held the idea that religious liberty was the greatest boon to be sought. But they were not capable of using it peaceably. Accustomed to look upon all authority in state or church as tyranny, they fell readily under the influence of agitators and adventurers who could not be kept out of the Province and whose presence caused Pennsylvania to be somewhat intemperately called “the greatest refuge for pirates and rogues in Ameri-ca.” Confusion and strife resulted and prevailed most conspicuously in the domain of religion.
Bilateral non-familial renal cell carcinoma

Background: Bilateral renal cell carcinoma (RCC) exists in hereditary forms (von Hippel-Lindau disease, hereditary papillary renal cell carcinoma, and hereditary clear cell renal carcinoma) associated with various chromosomal abnormalities, and non-hereditary, apparently sporadic forms. The focus of this study is the clinical description of the latter entity.
The p53 gene and protein in human brain tumors.

Because p53 gene alterations are commonplace in human tumors and because p53 protein is involved in a number of important cellular pathways, p53 has become a topic of intensive investigation, both by basic scientists and clinicians. p53 was initially identified by two independent laboratories in 1979 as a 53 kilodalton (kD) protein that complexes with the large T antigen of SV40 virus. Shortly thereafter, it was shown that the E1B oncoprotein of adenovirus also binds p53. The binding of two different oncogenic viral tumor proteins to the same cellular protein suggested that p53 might be integral to tumorigenesis. The human p53 cDNA and gene were subsequently cloned in the mid-1980s, and analysis of p53 gene alterations in human tumors followed a few year later. During these 10 years, researchers grappling with the vagaries of p53 first characterized the gene as an oncogene, then as a tumor suppressor gene, and most recently as both a tumor suppressor gene and a so-called [open quotes]dominant negative[close quotes] oncogene. The last few years have seen an explosion in work on this single gene and its protein product. A review of a computerized medical database revealed approximately 650 articles on p53 in 1992 alone. p53more » has assumed importance in neuro-oncology because p53 mutations and protein alterations are frequent in the common diffuse, fibrillary astrocytic tumors of adults. p53 mutations in astrocytomas were first described in 1989 and were followed by more extensive analyses of gene mutations and protein alterations in adult astrocytomas. The gene has also been studied in less common brain tumors. Elucidating the role of p53 in brain tumorigenesis will not only enhance understanding of brain tumor biology but may also contribute to improved diagnosis and therapy. This discussion reviews key aspects of the p53 gene and protein, and describe their emerging roles in central nervous system neoplasia. 102 refs., 6 figs., 1 tab.« less
Promoting health among perimenopausal women through diet and exercise.

Purpose To review the literature related to health promotion during the perimenopausal years and suggest methods for integrating those changes into the lifestyles of women in primary care. Data Sources Selected scientific literature and guidelines for exercise programs. Conclusions The transition into perimenopause presents an opportunity for addressing health promotion issues, such as diet and exercise. As a woman senses perimenopausal changes, health awareness emerges. Such personal insight motivates the woman to implement lifestyle changes. Implications for Practice Considering the average women will spend approximately one third of her life past menopause, a concerted effort is needed to ensure her well-being. Diet and exercise represent two modifiable areas of concern for perimenopausal women. Dietary selections of phytoestrogens, calcium, fiber and fat along with exercises plans are relatively simple interventions to begin the process of change.
How should we interpret and value the pursuit of blood-based biomarkers for autism spectrum disorders?

WHAT IS THE CLINICAL VALUE OF AUTISM BIOMARKERS? n increasingly common theme of research published in the Journal is the pursuit A of “biomarkers” for neurodevelopmental disorders that are costly, time consuming, or otherwise difficult to diagnose. Autism spectrum disorders (ASDs), for example, can be diagnosed reliably by a comprehensive behavioral evaluation by an experienced clinician based on the expression of characteristic behaviors for a protracted period. Obstacles on the path toward an accurate and efficient diagnosis in a given community are manifold, potentially including limited availability of trained professionals, uncertainty introduced by a spectrum of related but heterogeneous disorders and by comorbid conditions, parents’ reservations regarding the potential for denial of insurance coverage, parents’ fears of stigmatization of their children, and/or parents’ denial of a problem (despite having a sense that something is amiss). Because of these hurdles, the typical age at ASD diagnosis still lags far behind the typical age of first behavioral signs. This gap represents a critical missed opportunity for treatment. Biomarker research is fundamentally oriented toward decreasing this gap so that potentially affected children can receive appropriate intervention at the youngest possible age (perhaps even before behavioral signs), which in turn can improve prognoses and outcomes.
Polymer chain dimensions in mixed‐solvent media

The equilibrium between a linear polymer molecule and a binary solvent mixture in which it is immersed has been treated. An equation has been derived relating the resulting molecular expansion to the thermodynamic parameters for the ternary system and to the solvent composition. Intrinsic viscosity measurements are reported for polystyrene fractions in three mixed-solvent systems: methyl ethyl ketone-methanol, carbon tetrachloride-cyclohexane, and benzene-cyclohexane. Intrinsic viscosities measured for polystyrene fractions in critical consolute mixtures agree with those found in single poor solvents at the analogous Theta points. Intrinsic viscosities have been measured over ranges of mixed-solvent composition for the second and third solvent mixtures mentioned. Poor agreement with theory is observed for the former, but the more extensive measurements in benzene-cyclohexane mixtures agree very well with theoretically calculated intrinsic viscosities.
L2-lower bounds for a special class of random walks

We investigate theL 2-speed of convergence to stationarity for a certain class of random walks on a compact connected Lie group. We give a lower bound on the number of stepsk necessary such that thek-fold convolution power of the original step distribution has anL 2-density. Our method uses work by Heckman on the asymptotics of multiplicities along a ray of representations. Several examples are presented.
Statistics of fragmentation in a single-fiber composite under matrix yielding and debonding with application to the strength of multi-fiber composites

We study the statistics of fiber fragmentation in a single-fiber composite (SFC) when matrix yielding followed by interface debonding and fiber slip occur near fiber breaks as the applied strain is increased. Fiber strength is governed by flaws that follow Weibull/Poisson statistics. The model assumes that, under increasing applied strain on the SFC, fiber breaks occur randomly along the fiber from which matrix yield zones grow. At a critical strain, debond zones also initiate and grow from these breaks, resulting in fiber sliding with friction at the interface. This results in a two-step, shear traction profile producing bi-linear fiber stress recovery from breaks up to a plateau stress. These zones of yielding and debonding form growing exclusion zones around breaks within which further fiber fractures cannot occur. Eventually such zones cover the fiber, a condition called saturation. We model the fragmentation process by using a newly developed statistical theory that embodies the exclusion zone concept. Key parameters are the debond stress and the friction-yield stress ratio. These parameters are varied to determine the effects of debonding on the average fiber fragmentation length versus applied strain. We also obtain accurate estimates of the mean and variance in the stress along a fiber versus applied strain, and mention complications involved in obtaining the true values. These quantities are used to study the strength distribution and toughness of a long multi-fiber composite undergoing global load-sharing among fibers. Finally, we suggest how to estimate the model parameters from SFC test data.
B2(BO)22- Diboronyl Diborene: A Linear Molecule with a Triple Boron−Boron Bond

We have produced and investigated an unique boron oxide cluster, B4O2-, using photoelectron spectroscopy and ab initio calculations. Relatively simple and highly vibrationally resolved PES spectra were obtained at two photon energies (355 and 193 nm). The electron affinity of neutral B4O2 was measured to be 3.160 ± 0.015 eV. Two excited states were observed for B4O2 at excitation energies of 0.48 and 0.83 eV above the ground state. Three vibrational modes were resolved in the 355 nm spectrum for the ground state of B4O2 with frequencies of 350 ± 40, 1530 ± 30, and 2040 ± 30 cm-1. Ab initio calculations showed that neutral B4O2 (D∞h, 3Σg-) and anionic B4O2- (D∞h, 2Πu) both possess highly stable linear structures (O⋮BBBB⋮O), which can be viewed as a B2 dimer bonded to two terminal boronyl groups. The lowest nonlinear structures are at least 1.5 eV higher in energy. The calculated electron detachment energies from the linear B4O2- and the vibrational frequencies agree well with the experimental results. The ...
Indomethacin prevents the L-NAME-induced increase in plasma levels of oxytocin in dehydrated rats.

Abstract Inhibiting NO synthase (NOS) with N G -nitro- l -arginine methyl ester ( l -NAME, 250 μg/5 μl of artificial cerebrospinal fluid (aCSF)) injected intracerebroventricularly (i.c.v.) increased already enhanced levels of oxytocin, but not vasopressin, in conscious adult male Sprague–Dawley rats dehydrated for 24 h. Intracerebroventricular pretreatment with indomethacin (200 μg/5 μl aCSF), an inhibitor of cyclo-oxygenase, but not with losartan (25 μg/5 μl aCSF), an antagonist of angiotensin II (ANG II) AT 1 -receptor subtype, nearly prevented the elevation in oxytocin levels after l -NAME. Thus, NO inhibits prostaglandin (but not ANG II) mediated the modulatory actions of NO on oxytocin secretion from the hypothalamo-neurohypophysial system (HNS) during water deprivation.
Spring and summertime diurnal surface ozone fluxes over the polar snow at Summit, Greenland

were consistently � 0.01 cm s � 1 . During summer, ozone fluxes displayed distinct diurnal cycles, and evidence for regular occurrences of bi-directional behavior. Summer, daytime vd ranged between � 0.01 to 0.07 cm s � 1 . Maximum summertime downward fluxes (ozone deposition) coincided with the hours of maximum solar radiation, i.e., noon– afternoon. During summer nighttime hours upward ozone fluxes were observed. These upward fluxes were interpreted as ozone production in a shallow layer near and above the snow surface with resulting upward ozone fluxes out of the shallow surface layer. Comparisons with published observations from temperate, midlatitude sites suggest different controls and behavior of ozone fluxes, and that ozone fluxes over snow depend on a myriad of parameters, including solar irradiance, snow chemical and physical properties, snowpack depth, and the type of substrate underneath the snow. Citation: Helmig, D., L. D. Cohen, F. Bocquet, S. Oltmans, A. Grachev, and W. Neff (2009), Spring and summertime diurnal surface ozone fluxes over the polar snow at Summit, Greenland, Geophys. Res. Lett., 36, L08809,
Crystal and molecular structure of bis(8-phenylmenthyl) 2-(2-methyl-5-oxo-3-cyclohexen-1-yl)propandioate, C 42 H 54 O 5 · CH 3 CN

The X-ray crystal structure of the title compound, as crystallized from acetonitrile-water was determined. The relative stereochemistry of the cyclohexenone ring with respect to the 8-phenylmenthyl esters was determined. The title compound crystallizes in the noncentrosymmetric space group P21, with a=8.9850(10) A, b=15.575(3) A, c=14.478(2) A, β=94.61(2)°, and D calc=1.118 g cm−3 for Z=2.
The role of structural context in perception: Syntax in the recognition of algebraic expressions

Two character-identification experiments investigated the function of structural context during the processing of briefly exposed algebraic strings. Neither experiment prodded evidence to support the notion of an algebra-superiority effect, a contextually driven enhancement of the recognition of specific algebraic characters. However, the results of Experiment 2 indicate that the structure of algebra does provide information at the level of a character’s categorical denomination. These findings suggest that the parsing of an algebraic string includes a level of processing in which its structural context places restrictions on the denominations of its symbols. A processing model of algebraic perception is proposed that incorporates these syntactic constraints—constraints that appear to be independent of feature-based character identification processes.
Emergency Management Students' Perceptions of the Use of WebEOC[R] to Support Authentic Learning

This study investigates the use of software technology that is used by emergency management professionals to create an authentic learning environment in emergency and disaster management courses in the classroom. Participants were 235 upper-level students enrolled in residential and online emergency and disaster management courses at a mid-sized public university in the southeastern USA. Students participated in simulated disaster exercises that were presented through the software; further, as part of the exercise, students used the software to respond to the simulated disaster. Students then completed a survey to assess their perceptions of whether the exercises and software created an authentic learning environment and enhanced learning.
Metformin and vascular protection: a cardiologist's view

The predicted global epidemic of type 2 diabetes highlights the importance of identifying the most effective ways to reduce the risk of long-term diabetic complications. Although hyperglycaemia is undoubtedly a risk factor for microvascular complications, intensive glycaemic management has delivered only modest improvements in macrovascular endpoints thus far. A multidisciplinary approach addressing the components of the dysmetabolic syndrome, including insulin resistance, dyslipidaemia, hypertension, obesity and impaired fibrinolysis, will be required to protect the cardiovascular system more effectively. The potential vascular protective effects of metformin, demonstrated by the UK Prospective Diabetes Study, may complement other strategies within such a framework.
The Alzheimer’s Peptides Aβ40 and 42 Adopt Distinct Conformations in Water: A Combined MD / NMR Study

The role of peptides Aβ40 and Aβ42 in the early pathogenesis of Alzheimer's disease (AD) is frequently emphasized in the literature. It is known that Aβ42 is more prone to aggregation than Aβ40, even though they differ in only two (IA) amino acid residues at the C-terminal end. A direct comparison of the ensembles of conformations adopted by the monomers in solution has been limited by the inherent flexibility of the unfolded peptides. Here, we characterize the conformations of Aβ40 and Aβ42 in water by using a combination of molecular dynamics (MD) and measured scalar 3JHNHα data from NMR experiments. We perform replica exchange MD (REMD) simulations and find that classical forcefields reproduce the NMR data quantitatively when the sampling is extended to the microseconds time-scale. Using the quantitative agreement of the NMR data as a validation of the model, we proceed to compare the conformational ensembles of the Aβ40 and Aβ42 peptide monomers. Our analysis confirms the existence of structured regions within the otherwise flexible Aβ peptides. We find that the C terminus of Aβ42 is more structured than that of Aβ40. The formation of a β-hairpin in the sequence 31IIGLMVGGVVIA involving short strands at residues 31–34 and 38–41 (in bold) reduces the C-terminal flexibility of the Aβ42 peptide and may be responsible for the higher propensity of this peptide to form amyloids.
Mucosal abnormalities of the colon in patients with portal hypertension: An endoscopic study ☆ ☆☆

Abstract Background: Controversy still exists regarding colonic mucosal abnormalities in patients with portal hypertension (portal colopathy). The aims of this study were to better define portal colopathy and to identify risk factors for these colonic mucosal abnormalities. Methods: We reviewed the medical records of 437 patients with cirrhosis and portal hypertension and 224 with irritable bowel syndrome (control patients) who underwent colonoscopy over a 6-year period. Results: Individuals with portal hypertension were significantly more likely than control patients to have colitis-like abnormalities (38% vs. 3%, p p p p p = 0.003) were independently associated with an increased risk of having portal colopathy, whereas the use of β-blockers independently decreased the risk of having these findings (odds ratio 0.23: 95% CI [0.13, 0.40]; p Conclusions: Mucosal abnormalities in portal colopathy include edema, erythema, granularity, friability, and vascular lesions, findings that may be confused with colitis. A standardized grading system to classify the endoscopic appearance and severity of portal colopathy should be adopted. (Gastrointest Endosc 2000;52:511-6.)
Elusive reform : the French universities, 1968-1978

(1980). Elusive Reform: The French Universities, 1968–1978. The Journal of Higher Education: Vol. 51, No. 1, pp. 106-108.
Early versus delayed imaginal exposure for the treatment of posttraumatic stress disorder following accidental upper extremity injury

Background The consequences following work-related injuries are far reaching, which are in part due to unrecognized and untreated posttraumatic stress disorder (PTSD). Imaginal exposure is a frequently used cognitive behavioral approach for the treatment of PTSD. This study examined the impact of early versus delayed treatment with imaginal exposure on amelioration of PTSD symptomatology in individuals who suffered upper extremity injuries.
Living ring opening metathesis polymerization of mesogenic norbornene derivatives

A new class of SCLCPs was prepared by polymerizing mesogenic norbornene derivatives using Mo(CHCMe2R)(N-2,6-C6H3-i-Pr2)(O-t-Bu)2 (R = CH3 or Ph). Monomers based on norbornene ring systems were chosen because the rings are highly strained and therefore yield irreversible polymerizations. The Mo-alkylidene initiators were chosen because they initiate norbornene derivatives relatively fast and quantitatively, and provide stable chain ends which have low reactivity to both the internal double bonds of the polymer backbone and the functional groups present in the monomers. The apparent absence of termination and transfer reactions in ROMP results in polymerizations which appear to be living, and the fast initiation and irreversible chain growth leads to polymers with narrow molecular weight distributions in which the degree of polymerization is controlled by the ratio of monomer to initiator used. The resulting well-defined polymers were used to determine the most basic structure-property relationships of this new class of SCLCPs. The thermotropic behavior of both terminally attached and laterally attached SCLCPs based on polynorbornene backbones becomes independent of molecular weight at approximately 25 repeat units. In addition, polydispersity was found to have no effect on the breadth of nematic phase transitions in the terminally attached polymers, with the transition temperature determined simply by the number average degree of polymerization.
Chemometric categorization of octadecylsilyl bonded-phase silica columns using test mixtures and confirmation of results with pharmaceutical compound separations

Abstract The chromatographic properties of seventeen commercial octadecylsilyl phases were characterized in order to determine column similarities and differences that would aid in column selection for method development, choice of an alternate column and method ruggedness testing. Chromatographic test mixtures from the literature were used to probe the hydrophobicity, free silanol interactions, trace metal activity, and shape selectivity of these columns. Principal components and cluster analysis methods were used to categorize the columns into groups that tended to display similar chromatographic properties. The validity of the groups was tested with mixtures of pharmaceutical compounds under a variety of mobile phase conditions. In general, columns that were categorized together from the test mixture analysis showed similar behavior for the analysis of the pharmaceutical compound mixtures.
Evaluation of the Webler-Brown model for estimating tetrachloroethylene exposure from vinyl-lined asbestos-cement pipes.

From May 1968 through March 1980, vinyl-lined asbestos-cement (VL/AC) water distribution pipes were installed in New England to avoid taste and odor problems associated with asbestos-cement pipes. The vinyl resin was applied to the inner pipe surface in a solution of tetrachloroethylene (perchloroethylene, PCE). Substantial amounts of PCE remained in the liner and subsequently leached into public drinking water supplies. Once aware of the leaching problem and prior to remediation (April-November 1980), Massachusetts regulators collected drinking water samples from VL/AC pipes to determine the extent and severity of the PCE contamination. This study compares newly obtained historical records of PCE concentrations in water samples (n = 88) with concentrations estimated using an exposure model employed in epidemiologic studies on the cancer risk associated with PCE-contaminated drinking water. The exposure model was developed by Webler and Brown to estimate the mass of PCE delivered to subjects' residences. The mean and median measured PCE concentrations in the water samples were 66 and 0.5 μg/L, respectively, and the range extended from non-detectable to 2432 μg/L. The model-generated concentration estimates and water sample concentrations were moderately correlated (Spearman rank correlation coefficient = 0.48, p < 0.0001). Correlations were higher in samples taken at taps and spigots vs. hydrants (ρ = 0.84 vs. 0.34), in areas with simple vs. complex geometry (ρ = 0.51 vs. 0.38), and near pipes installed in 1973–1976 vs. other years (ρ = 0.56 vs. 0.42 for 1968–1972 and 0.37 for 1977–1980). Overall, 24% of the variance in measured PCE concentrations was explained by the model-generated concentration estimates (p < 0.0001). Almost half of the water samples had undetectable concentrations of PCE. Undetectable levels were more common in areas with the earliest installed VL/AC pipes, at the beginning and middle of VL/AC pipes, at hydrants, and in complex pipe configurations. PCE concentration estimates generated using the Webler-Brown model were moderately correlated with measured water concentrations. The present analysis suggests that the exposure assessment process used in prior epidemiological studies could be improved with more accurate characterization of water flow. This study illustrates one method of validating an exposure model in an epidemiological study when historical measurements are not available.
Synaptic activity and excitability modulates information transfer in Purkinje cells: a modeling study.

Dendritic excitability is the consequence of the different concentration and distribution of active conductances. The excitability of the cell could be a mechanism for storing memories and is affected by development and experience. Information in Purkinje cells (PCs) flows from dendrites to soma without the influence of backpropagating action potentials. Thus, PCs are ideal to quantify the incremental contribution of dendritic channels to information processing. We used a previously published PC model [1,2]. The model was stimulated with several combinations of excitatory and inhibitory rates of synaptic activity (EIr). Since our objective was to quantify information processing in dendrites we chose EIr to evoke the same firing rate at the soma. The simulations were run for 400 s; the total current of all the synaptic and dendritic channels was recorded every 0.1 ms; and were implemented in a pre-release version of GENESIS 3 (http://www.genesis-sim.org/; http://www.cbi.utsa.edu). We quantified the effects of several EIr on the histogram of each dendritic current. We found that only the histograms of the CaP (ICaP) and Kc currents (IKc) varied, while all others remained constant. The source of this variability comes from the synaptic activity and from interactions among channels. We used mutual information (MI) to quantify the information from the total excitatory synaptic current (IGlu) encoded in each dendritic current. In this context, each active current was considered an information channel. MI(ICaP, IGlu) and MI(IKc, IGlu) was sensitive to different EIr that resulted in the same firing rate at the soma. We quantified the changes in MI(ICaP, IGlu) and MI(IKc, IGlu) as a function of the density of dendritic conductances (gCaP and gKc). This analysis showed that MI(ICaP, IGlu) was less sensitive to changes in gCaP than to variations in gKc. Thus, the interactions between IKc and ICaP are important to regulate information transfer in the dendrite. We extended our analysis to determine MI(ICaP(t) or IKc(t), IGlu(t-Δt)), for Δt from 0 to 1 s and as a function of channel density and EIr. We found that MI decayed in about 100 ms as a function of the combination of gCaP and gKc with the level of synaptic activity, reducing this window to a few milliseconds with high rates of EIr. Overall, our results show that different dendritic conductances differentially encode synaptic activity and that dendritic excitability and the level of synaptic activity regulate the flow of information in dendrites.
On measures of logic performance: logic quantum, factor, and figure of merit

A basic logic operation is considered of transferring a logic decision from one point to another point. A certain energy level, WL, corresponding to decision threshold and a time delay, TL, are encountered in the transfer process. The product, WLTL, is a logic quantum, HL. If the logic transfer takes place through an intermediate device, a logic factor, FL, can be introduced to describe the reduction in logic quanta that the device can produce under optimum conditions. Optimization is carried out, as for instance with ideal transformers, to "match" the logic source to the device and the device to the logic detector. The condition FL = 1 marks a boundary between a useful and a uselessd evice, and a logicf igure of merit, TPH,in units of time corresponds to the fastest source-detector combination such that FL = 1. Logic performance is considered in some detail for a particular linear model of a device. Nonlinear devices and relay devices are considered in less detail, although some numerical calculations are given for a current-switch, two-transistor computer device. The logic figure of merit represents a unique measure of high-speed logic performance and is therefore valuable in comparing devices including associated circuitry on a common basis.
Penetration of semliki forest virus from acidic prelysosomal vacuoles

To identify and characterize the intracellular site from which the penetration of Semliki Forest virus (SFV) to the cytosolic compartment of the host cell occurs, we determined the time course and temperature dependence of nucleocapsid uncoating and infection in BHK-21 cells. At 37 degrees C the genome release to the cytosol was detected within 5-7 min after virus endocytosis, whereas delivery of the virus particles to secondary lysosomes occurred within 15-20 min. At temperatures of 15 degrees -20 degrees C virus particles were internalized by endocytosis, but they were not delivered to the secondary lysosomes. Nevertheless, at 20 degrees C nucleocapsid uncoating and infection occurred, indicating that secondary lysosomes are not required for SFV penetration. We conclude that the penetration reaction occurs in prelysosomal endocytic vacuoles (endosomes). As SFV penetration by membrane fusion requires a pH less than 6 and the presence of cholesterol in the target membrane, the data indicate that endosomes are acidic and contain cholesterol.
The Single Ligand-binding Repeat of Tva, a Low Density Lipoprotein Receptor-related Protein, Contains Two Ligand-binding Surfaces

Abstract The receptor for avian sarcoma/leukosis virus subtype A (ASLV-A), Tva, is the simplest member of the low density lipoprotein receptor family containing a single ligand-binding repeat (LBR). Most LBRs contain a central Trp (Trp33 in Tva) that is important for ligand binding and, for the low density lipoprotein receptor, is associated with familial hypercholesterolemia. The Tva ligand-binding module contains a second Trp (Trp48) that is part of a DEW motif present in a subset of LBRs. Trp48 is important for ASLV-A infectivity. A soluble Tva (sTva) ligand-binding module is sufficient for ASLV-A infectivity. Tva interacts with the viral glycoprotein, and a soluble receptor-binding domain (SUA) binds sTva with picomolar affinity. We investigated whether Tva, a retroviral receptor, could behave as a classic LBR by assessing sTva interactions with the universal receptor-associated protein (RAP) and comparing these interactions with those between sTva and its viral ligand (SUA). To address the role of the two Trp residues in Tva function, we prepared sTva harboring mutations of Trp33, Trp48, or both and determined the binding kinetics with RAP and SUA. We found that sTva behaved as a “normal” receptor toward RAP, requiring both calcium and Trp33 for binding. However, sTva binding to SUA required neither calcium nor Trp33. Furthermore, sTva could bind both RAP and SUA simultaneously. These results show that the single LBR of Tva has two ligand-binding sites, raising the possibility that other LBRs may also.
Intentional weight loss and incidence of obesity-related cancers: the Iowa Women's Health Study.

OBJECTIVE: To examine the association of voluntary vs involuntary weight loss with incidence of cancer in older women. DESIGN: Prospective cohort study from 1993 to 2000, with cancer incidence identified through record linkage to a cancer registry. SUBJECTS: A total of 21 707 postmenopausal women initially free of cancer. MESUREMENTS: Women completed a questionnaire about intentional and unintentional weight loss episodes of ≥20 pounds during adulthood. RESULTS: Compared with women who never had any ≥20 pounds weight loss episode, women who ever experienced intentional weight loss ≥20 pounds but no unintentional weight loss had incidence rates lower by 11% for any cancer (RR=0.89, 95% CI 0.79–1.00), by 19% for breast cancer (RR=0.81, 95% CI 0.66–1.00), by 9% for colon cancer (RR=0.91, 95% CI 0.66–1.24), by 4% for endometrial cancer (RR=0.96, 95% CI 0.61–1.52), and by 14% for all obesity-related cancer (RR=0.86, 95% CI 0.74–1.01) after adjusting for age, body mass index, waist-to-hip ratio, physical activity, education, marital status, smoking status, pack-years of cigarettes, current estrogen use, alcohol use, parity, and multivitamin use. Furthermore, although overweight women were at increased risk of several cancers, women who experienced intentional weight loss episodes of 20 or more pounds and were not currently overweight were observed to have an incidence of cancer similar to nonoverweight women who never lost weight. Unintentional weight loss episodes were not associated with decreased cancer risk. CONCLUSIONS: These findings suggest that intentional weight loss might reduce risk of obesity-related cancers.
Reduced functional connectivity between V1 and inferior frontal cortex associated with visuomotor performance in autism

Some recent evidence has suggested abnormalities of the dorsal stream and possibly the mirror neuron system in autism, which may be responsible for impairments of joint attention, imitation, and secondarily for language delays. The current study investigates functional connectivity along the dorsal stream in autism, examining interregional blood oxygenation level dependent (BOLD) signal cross-correlation during visuomotor coordination. Eight high-functioning autistic men and eight handedness and age-matched controls were included. Visually prompted button presses were performed with the preferred hand. For each subject, functional connectivity was computed in terms of BOLD signal correlation with the mean time series in bilateral visual area 17. Our hypothesis of reduced dorsal stream connectivity in autism was only in part confirmed. Functional connectivity with superior parietal areas was not significantly reduced. However, the autism group showed significantly reduced connectivity with bilateral inferior frontal area 44, which is compatible with the hypothesis of mirror neuron defects in autism. More generally, our findings suggest that dorsal stream connectivity in autism may not be fully functional.
A Prospective Assessment of Carpal Tunnel Surgery with Respect to Age

Six hundred and thirty five carpal tunnel decompressions in 490 patients were studied prospectively in two hand surgery centres to assess the effect of increasing age on the outcome after surgery. The outcome was assessed using the Levine-Katz carpal tunnel questionnaire, Tinel's sign, Phalen's test, Semmes-Weinstein monofilaments and pinch and grip strengths. Assessments were made pre-operatively, at 2 weeks and 6 months postoperatively. Information was also sought concerning co-morbid conditions. Cases were divided into four groups (less than 40 years of age, 40 to 60, 61 to 80, and over 80 years of age). Patients improved significantly in all age groups after carpal tunnel surgery. Despite a relatively high number of co-morbidities, older patients had an acceptable complication rate and their improvement was comparable to all other age groups.
Anxiety in healthy humans is associated with orbital frontal chemistry

The present study examines relationships between regional brain chemistry (as identified by localized in vivo three-dimensional single-voxel proton magnetic resonance spectroscopy (1H-MRS) and anxiety (as measured by the State-Trait Anxiety Inventory) in 16 healthy subjects. The relative concentrations of N-Acetyl aspartate, choline, glutamate, glutamine, γ-aminobutyric acid, inositol, glucose and lactate were measured relative to creatine within six 8-cm3 brain voxels localized to: thalamus, cingulate, insula, sensorimotor, dorsolateral prefrontal, and orbital frontal cortices (OFC) in the left hemisphere. Analysis of variance, across brain regions, chemicals, and high and low anxiety groups, showed a relationship between anxiety and chemical composition of OFC, with high anxiety subjects demonstrating 32% increase in overall chemical concentrations within OFC, as compared to the lower anxiety group (F = 60.8, P < 10−7). Other brain regions, including cingulate, showed no detectable anxiety dependence. The combination of the state and trait anxiety was highly correlated with the concentration of OFC chemicals (r2 = 0.98), and N-Acetyl aspartate in OFC was identified as the strongest chemical marker for anxiety (changed by 43.2% between the two anxiety groups, F = 21.5, P = 0.000005). The results provide direct evidence that the OFC chemistry is associated with anxiety in healthy humans. The method can be used as a neuroimaging/behavioral tool for documentation of OFC chemistry changes in relation to anxiety per se and anxiety disorders. The presented relationship between regional brain chemistry and anxiety reflects the functional/behavioral state of the brain, pointing to possible mechanisms of the neurobiology of anxiety.