cssi/SciSciGPT-SciSciNet huggingface dataset:
Experimental Evidence for the Reorganization of β-Strands within Aggregates of the Aβ(16−22) Peptide

Amyloidogenic deposits that accumulate in brain tissue with the progression of Alzheimer's disease contain large amounts of the amyloid β-peptide. A small fragment of this peptide, comprising residues 16−22 (Aβ(16−22)), forms β-sheets in isolation, which then aggregate into amyloid fibrils. Here, using isotope edited infrared spectroscopy to probe the secondary structure of the peptide with residue level specificity, we are able to show conclusively that the β-sheets formed are antiparallel and, following an anneal cycle or prolonged incubation, are in register with the central residue (Phe19) in alignment across all strands. The alignment of strands proceeds via a rapid interchange from one sheet to another. This realignment of the peptide strands into a more favorable registry may have important implications for therapeutics since previous work has shown that well aligned β-sheets form more stable amyloid fibrils.
Supramolecular chemistry of cascade polymers: Construction, molecular inclusion, and inorganic connectivity

The construction of cascade polymers with novel properties is discussed. A flexible amide-based cascade architecture facilitates changes of the molecular hydrodynamic radius as a function of environmental pH, provided that the periphery is coated with ionizable functional groups (e.g., carboxylic acids or amines). Thus, it is possible to expand or contract the internal void domains within these cascades. By extension of the heteroatom connectivity, we have prepared a novel multifunctional molecule possessing a predetermined spherical morphology, that utilizes a ruthenium(II) metal center coordinated to two different orthogonal 2,2':6',2″-terpyridine moieties to build the arm(s) of the cascade polymer. This technology permits the placement of multiple metal complexes at predetermined internal sites within the hydrophilic-surfaced MicellaneTM framework. The combination of these two strategies to build cascade polymers allows the creation of an unsymmetrical bolaamphiphile constructed from two separate and distinct macromolecules. We are able to build cascade molecules either with a terpyridine unit inside or outside the polyamide sphere. The use of a connecting ruthenium(II) center allows the specific formation of a stable complex between the discrete cascade polymers.
Leukocyte-endothelial adhesion is impaired in the cremaster muscle microcirculation of the copper-deficient rat.

Abstract Dietary copper deficiency impairs the function of both the vascular endothelium and circulating leukocytes. In the current study, leukocyte–endothelium adhesion was observed in the in vivo cremaster muscle microcirculation of copper-adequate and copper-deficient rats. Male, weanling Sprague–Dawley rats were fed purified diets that were either adequate (5.6 μg/g) or deficient (0.3 μg/g) in copper. Adhesion was stimulated with the inflammatory mediators tumor necrosis factor-α and bradykinin, and the chemotactic peptide N -formyl-methionyl-leucyl-phenylalanine. Intravascular adhesion of leukocytes to the vascular endothelium was significantly attenuated in the copper-deficient group in response to all three agonists. These results occurred without any difference in intravascular wall shear rate between the dietary groups. Based on previous work, we propose that the attenuated response is caused by either decreased expression of adhesion molecules on leukocytes and endothelial cells or by inhibition of the endothelial cell calcium signaling associated with copper deficiency.
Thymus-Dependent Lymphocytes: Destruction by Lymphocytic Choriomeningitis Virus

Selective destruction of small lymphocytes in the thymusdependent areas of lymph nodes and thymocytes was observed in mice infected with lymphocytic choriomeningitis virus. These changes were clearly evident in lymphoid and splenic tissue 3 days after infection and in the thymus by day 7. The destructive changes paralleled growth of the virus in these organs. The findings show that infection with lymphocytic choriomeningitis virus can temporarily cause the equivalent effect of neonatal thymectomy, that is, a "viral thymectomy," which appears to be related to the ability of this virus to cause persistent infection.
Using biomarkers as objective standards in the diagnosis of cervical biopsies.

Histopathologic diagnosis of cervical biopsies determines clinical management of patients with an abnormal cervical cancer-screening test yet is prone to poor interobserver reproducibility. Immunohistochemical staining for biomarkers related to the different stages of cervical carcinogenesis may pro
Role of Molecular Architecture in Organic Photovoltaic Cells

What are the stumbling blocks for achieving high-efficiency organic photovoltaic devices? This question is examined from a molecular architecture and molecular packing perspective. The intermolecular interaction between the electron donor and electron acceptor influences the charge separation. The packing of electron donors and acceptors influences the charge transport. Therefore, there is a need to strike a balance between the charge-transfer interactions and packing interactions and obtain nanoscale segregated morphologies for efficient charge separation and charge transport. Molecular architecture is key toward striking this balance and, therefore, its impact on charge-transfer interactions and packing interactions; thus, the active-layer morphology and photovoltaic metrics are examined. A variety of molecular architectures for the packing of π-conjugated organic molecules to structures relevant for photovoltaic devices is also discussed.
Operative versus nonoperative management of ureteropelvic junction obstruction in children.

Objectives To describe and validate our strategy for treating patients with ureteropelvic junction obstruction operatively or nonoperatively according to ultrasonography and nuclear renal scan findings. Methods A retrospective analysis of 243 patients from 1999 to 2006 with grade 3-4 hydronephrosis was performed. Depending on the grade of hydronephrosis with parenchymal thinning on ultrasonography and renal function on the nuclear renal scan, patients were treated with immediate pyeloplasty, pyeloplasty after a period of observation, or observation only. Results Of 243 patients, 116 were found to have UPJO as determined by a half-life >20 minutes. The mean follow-up was 24.0 months (range 3-69). Immediate pyeloplasty was performed in 32 children, and 84 were treated conservatively. Crossover from observation to surgery occurred in 47 children. In the immediate pyeloplasty group, the mean pre- and postoperative differential function was 30.4% and 38.8%, respectively ( P P = .2764). In the delayed pyeloplasty group (n = 47), the initial mean renal function was 35.9% and increased to a mean of 41.6% after intervention ( P = .0003). The median improvement of hydronephrosis on ultrasonography for those who underwent immediate surgery from before to after the intervention was from grade 4 to grade 3 ( P P = .0026) and for those who underwent delayed surgery, from grade 4 to 3 ( P = .0003). Conclusions According to our findings, the serial ultrasonography findings and initial renal function on nuclear renal scan are better indicators than the half-life alone for determining whether pyeloplasty is indicated.
The Navajo SMF Type Subsynchronous Resonance Relay

A Subsynchronous Resonance (SSR) Protective relay first applied at the Navajo Plant, in conjunction with other primary SSR protective means, is described.
Sizes of test sets for path delay faults using strong and weak non-robust tests

The trade-off between strong and weak non-robust tests for path delay faults considering test quality, test set size and fault coverage is discussed. It is noted that strong non-robust tests detect more combinations of delay defects. However, weak non-robust tests result in smaller test sets, and more path delay faults are detectable by weak non-robust tests. A test generation strategy that mixes strong and weak non-robust tests based on this trade-off is described. Under the proposed strategy, test generation starts by generating strong non-robust tests. When the number of faults detected by each additional test drops below a certain level, indicating that low levels of compaction are achieved, test generation switches to weak non-robust tests. The authors study appropriate switching points experimentally by using a test selection procedure to construct mixed test sets. They also consider the effects of adding power constraints on the mix of strong and weak non-robust tests.
Collagen Shield Delivery of Amphotericin B

By using a high-pressure liquid chromatography assay, we investigated the ability of collagen shield therapeutic contact lenses to release amphotericin B and deliver it to the anterior segment of rabbit eyes. In vitro studies showed that presoaked collagen shields released most of the amphotericin B within the first hour of elution. We compared the corneal and aqueous humor amphotericin B levels produced by collagen shields soaked in amphotericin B and frequent-drop therapy at four time points over a six-hour period. The collagen shields soaked in amphotericin B produced corneal levels that were higher than those produced by frequent-drop therapy at one hour, equivalent to drop therapy at two and three hours, and lower than drop therapy at six hours. There were no differences in amphotericin B levels in aqueous humor at any time point between rabbits treated with collagen shield delivery and rabbits treated with frequent-drop delivery. The results of this study suggest that amphotericin B delivery to the cornea by collagen shields is comparable to frequent-drop delivery but has the potential benefit of added convenience and compliance.
Model Independent Analysis of Proton Structure for Hydrogenic Bound States

Proton structure effects in hydrogenic bound states are analyzed using nonrelativistic QED effective field theory. Implications for the Lamb shift in muonic hydrogen are discussed. Model-dependent assumptions in previous analyses are isolated, and sensitivity to poorly constrained hadronic structure in the two-photon exchange contribution is identified.
Recent results in nonlinear viscoelastic wave propagation

Abstract In this article we present a review of some recent theoretical and experimental developments in the field of nonlinear viscoelastic wave propagation. Confining our attention to the case of one-dimensional strain, we review the theories of shock and acceleration wave propagation in general materials with memory and discuss the correlation of these theoretical predictions with some recent experimental results obtained for a particular polymeric solid. Fundamental to this work is the existence of steady shock waves and the fact that they can be generated in a one-dimensional experimental configuration. Using such experimental steady wave observations, a procedure is outlined for determining the material response functions necessary for predicting the growth or decay of shock and acceleration waves in viscoelastic materials. It is further shown that by using a particular constitutive assumption (either purely mechanical or thermomechanical) the complete one dimensional constitutive equation governing the material response can be evaluated from steady shock wave measurements.
Improving the efficiency of multipath traffic via opportunistic traffic scheduling

Multipath routing, as defined by OSPF extensions and other protocols, enables a network's traffic to be split among two, or more, possibly disjoint paths. Advantages of multipath vs. unipath routing include load balancing, reduced latency, and improved throughput. However, once the control plane establishes multiple routes, a policy is needed for efficiently splitting traffic among the selected paths. In this paper, we introduce opportunistic multipath scheduling (OMS), a technique for exploiting short-term variations in path quality to minimize delay, while simultaneously ensuring that the splitting rules dictated by the routing protocol are satisfied. We develop a performance model of OMS and derive an asymptotic lower bound on the performance of OMS as a function of path conditions (mean, variance, and Hurst parameter) for self-similar traffic. Finally, we use an extensive simulation-based performance study to evaluate the accuracy of the analytical model, explore the impact of OMS on TCP throughput and performance of real-time traffic, and study the impact of factors such as delayed measurements.
Cadmium content of shellfish of the South Carolina fishery

Abstract A survey of cadmium residues in shellfish from the Atlantic Coast of South Carolina was undertaken to see the magnitude of cadmium contamination in the South Carolina Fishery. The shellfish collected were oysters, clams, crabs, shrimps, and scallops. Shellfish samples were dissected and pieces of edible muscle tissue were incubated in reagent grade nitric acid, at a constant temperature shaking-water bath at 58°C. Cadmium levels were determined by flame atomic absorption. The distribution pattern of the element Cd in shellfish is different in various species. It seems that shellfish contained more Cd content levels than other saltwater boney fish. It was found that Cd levels were relatively higher in oysters, shrimps, and clams than crabs and scallops. Larger shellfish had higher Cd content than the smaller shellfish of the same species. Elevated levels of Cd found in these shellfish species of edible fish were not high enough to render them dangerous for human consumption.
Preconditioning, randomization, solving linear systems, eigen-solving, and root-finding

We propose novel randomized preprocessing techniques for solving linear systems of equations and eigen-solving with extensions to the solution of polynomial and secular equations. According to our formal study and extensive experiments, the approach turns out to be effective, particularly in the case of structured input matrices.
Structure and function of methanogens along a short-term restoration chronosequence in the florida everglades

The removal of plants and soil to bedrock to eradicate exotic invasive plants within the Hole-in-the-Donut (HID) region, part of the Everglades National Park (Florida), presented a unique opportunity to study the redevelopment of soil and the associated microbial communities in the context of short-term primary succession and ecosystem restoration. The goal of this study was to identify relationships between soil redevelopment and activity and composition of methanogenic assemblages in HID soils. Methane production potentials indicated a general decline in methanogenic activity with restoration age. Microcosm incubations strongly suggested hydrogenotrophic methanogenesis as the most favorable pathway for methane formation in HID soils from all sites. Culture-independent techniques targeting methyl coenzyme M reductase genes (mcrA) were used to assess the dynamics of methanogenic assemblages. Clone libraries were dominated by sequences related to hydrogenotrophic methanogens of the orders Methanobacteriales and Methanococcales and suggested a general decline in the relative abundance of Methanobacteriales mcrA with time since restoration. Terminal restriction fragment length polymorphism analysis indicated methanogenic assemblages remain relatively stable between wet and dry seasons. Interestingly, analysis of soils across the restoration chronosequence indicated a shift in Methanobacteriales populations with restoration age, suggesting genotypic shifts due to site-specific factors.
Onconephrology: the need and the emergence of a subspecialty in nephrology

Onconephrology is a new and evolving field of subspecialization in nephrology that deals with the study of kidney diseases in cancer patients, and, by extension, a nephrologist who further specializes in onconephrology can be considered as an onconephrologist. Remarkable advances in cancer medicine have required many cancer programs to become subspecialized, for example, into lymphoma/myeloma, leukemia, stem-cell transplantation (SCT), and various solid-tumor programs. Onconephrology, however, is a broad term that currently encompasses kidney diseases in any cancer setting, whether the tumor is liquid or solid, although further specialization—for example, onconephrology in hematological cancer—remains a possibility.
A Serendipity cubic‐displacement hybrid‐stress element for thin and moderately thick plates

A hybrid-stress element is developed for the analysis of thin and moderately thick plates. The independent transverse displacement and rotations are interpolated by the 12-node cubic Serendipity shape functions. All components of stress are included and 36β stress assumption is used. The element stiffness possesses correct rank and numerical results indicate that the element does not lock in the thin-plate limit. Results obtained using the present element are compared with those obtained using a 12-node assumed-displacement based Mindlin plate element with reduced integration; the present hybrid-stress element is shown to yield superior accuracy for all cases considered. In addition, the accuracy of the present element is compared against that of analogous 4-node and 8-node hybrid-stress Mindlin plate elements.
A Statewide Evaluation of a Communication and Parenting Skills Program.

This study evaluated, through a state training network the Communication and Parenting Skills (CAPS) substance abuse education program. The program includes: 1) parental modeling of positive attitudes and behaviors and 2) effective communication. Ten instructors, located throughout the Commonwealth of Pennsylvania, each conducted two CAPS courses — one serving as an experimental course, the other as a control.The procedure followed for this project was a post-test only design. Comparative data revealed that the marital status and years in present residence for the two groups were very similar. The control group averaged one-half year more of education and one-half child less per family. Results from the Sensitivity to Children Index indicated a significant acquisition and utilization of constructive responses by participants in the experimental condition.
Mere Exposure and the Endowment Effect on Consumer Decision Making

Previous researchers (e.g., J. A. Bargh, 1992, 2002) demonstrated the importance of nonconscious processes on consumer choice behavior. Using an advertisement, the authors determined the effect of two nonconscious processes—the mere exposure effect, which increases object preference by increasing consumer exposure to an object, and the endowment effect, which increases object valuation by providing consumer possession of an object—on consumer behavior. Although the mere exposure effect and endowment effect did not produce an interaction, they produced independent effects. The endowment effect increased object valuation but not object preference. The mere exposure effect increased object preference but not object valuation. Thus, at the unconscious level, an increase in object preference does not lead to an increase in object valuation, nor does an increase in object valuation lead to an increase in object preference. The authors discuss the importance of developing measures of unconscious process in adver...
Analytical solution methods for the fuzzy weighted average

For the fuzzy weighted average (FWA), despite various discrete solution algorithms and their improvements, attempts at analytical solutions are very rare. This paper provides an analytical solution method for the FWA based on the conclusions of the Karnik-Mendel (KM) algorithm. Compared with the two current popular kinds of @a-cut based computational methods for the FWA (mathematical programming transformations and direct iterate computations), our method is precise, and, has a concise structure, efficient computation process, and sound theoretical proofs. We propose two algorithms for computing the analytical solution of the FWA. Two numerical examples illustrate our proposed approach.
Hierarchy of quantized Hall states in double-layer electron systems

Abstract The hierarchy of fractionally quantized Hall states of Haldane and Halperin is extended to the case of double-layer electron systems. Recursion relations for the filling fractions and flux shifts in the spherical geometry are derived and used to elaborate simple cases, including quasiparticle condensates with opposite charges in different layers. Extensive numerical studies are presented, which provide evidence for many of our predictions.
Environmental noise and human prenatal growth

To determine whether chronic exposure to relatively loud noise has demonstrable biological effects in humans, a study was conducted on the effect of mother's exposure to airport noise while pregnant, and of social and biological characteristics of the family upon birthweight and gestation length. The sample of births was drawn from a community located adjacent to an international airport in the U.S., where noise levels had been measured previously. Mother's noise exposure was based upon noise levels near her residence in the community while she was pregnant. Data from 115 births were used, these being from mothers whose noise exposure history was most complete throughout the pregnancy. Using multivariate analysis to correct for family characteristics, the partial correlation coefficient for noise exposure and gestation length was negative, large, and significant in girls (r = -0.49, p less than 0.001). In boys the partial correlation coefficient was also negative but was smaller and did not quite reach statistical significance. Partial correlations with birthweight were smaller in both boys and girls and not significant. These results agree best with previous studies that suggest that noise may reduce prenatal growth. The size of the observed effects may be related to a conservative research design biased towards underestimation, as well as to the real effects of noise upon human prenatal growth.
Relationship of winter concealment habitat quality on pool use by juvenile spring Chinook salmon (Oncorhynchus tshawytscha) in the Grande Ronde River Basin, Oregon USA

Winter concealment habitat quality was assessed and its use by juvenile spring Chinook salmon (Oncorhynchus tshawytscha) quantified in three hatch- ing areas of the Grande Ronde River Basin, Oregon USA. Fish densities were significantly higher in pools with a higher winter concealment habitat index than pools with a lower index. The mean fork length and mean growth rate of fish did not differ between pools with a higher or lower winter concealment habitat index, even though residual fish were significantly larger than fish that emigrated. Biomass-density was significantly higher in pools with a higher winter concealment habitat index than pools with a lower index in all three hatching areas. Biomass-density was positively associated with the amount of cobble substrate (10-24.9 cm/m 2 ) in all three hatching areas, and inversely associated with embeddedness in two of the hatching areas. Results of this study indicate that enhancing winter concealment habitat could improve habitat quality resulting in increased carrying capacity and winter usage by juvenile spring Chinook salmon.
MetNetAPI: A flexible method to access and manipulate biological network data from MetNet

Background: Convenient programmatic access to different biological databases allows automated integration of scientific knowledge. Many databases support a function to download files or data snapshots, or a webservice that offers “live” data. However, the functionality that a database offers cannot be represented in a static data download file, and webservices may consume considerable computational resources from the host server. Results: MetNetAPI is a versatile Application Programming Interface (API) to the MetNetDB database. It abstracts, captures and retains operations away from a biological network repository and website. A range of database functions, previously only available online, can be immediately (and independently from the website) applied to a dataset of interest. Data is available in four layers: molecular entities, localized entities (linked to a specific organelle), interactions, and pathways. Navigation between these layers is intuitive (e.g. one can request the molecular entities in a pathway, as well as request in what pathways a specific entity participates). Data retrieval can be customized: Network objects allow the construction of new and integration of existing pathways and interactions, which can be uploaded back to our server. In contrast to webservices, the computational demand on the host server is limited to processing data-related queries only. Conclusions: An API provides several advantages to a systems biology software platform. MetNetAPI illustrates an interface with a central repository of data that represents the complex interrelationships of a metabolic and regulatory network. As an alternative to data-dumps and webservices, it allows access to a current and “live” database and exposes analytical functions to application developers. Yet it only requires limited resources on the server-side (thin server/fat client setup). The API is available for Java, Microsoft.NET and R programming environments and offers flexible query and broad data- retrieval methods. Data retrieval can be customized to client needs and the API offers a framework to construct and manipulate user-defined networks. The design principles can be used as a template to build programmable interfaces for other biological databases. The API software and tutorials are available at http://www.metnetonline.org/api.
The influence of the ternary interaction parameter ε -Bi Fe on the activity of bismuth in molten copper

The first order ternary interaction parameter, e -Bi Fe , for bismuth in molten copper has been evaluated using a pseudo equilibrium process. The results indicate that the interaction parameter can be represented by the following equation: $$\varepsilon _{Bi}^{Fe} = \frac{{1.1 \cdot 10^6 }}{T}--750 (1398< T< 1469 K$$ The large positive value of e -Bi Fe near the melting point temperature of copper is consistent with the three binary phase diagrams that bound the Cu-Fe-Bi ternary. The experimental results are used to calculate the isoactivity curves for each constituent in the copper-rich corner of the ternary system. The experimental results also indicate that the ternary interaction parameter strongly affects the activity curves as temperature is decreased.
Sensitivity of the circadian rhythm of kainic acid-induced convulsion susceptibility to manipulations of corticosterone levels and mineralocorticoid receptor binding

Abstract Increases in Corticosterone levels have been associated with enhanced susceptibility and decreases in Corticosterone levels have been associated with decreased susceptibility to convulsions in mice. The proconvulsant effects of Corticosterone are believed to be mediated by central mineralocorticoid receptors (MR). Both convulsion susceptibility and plasma corticosteroid levels display circadian rhythmicity. When Corticosterone levels are at their lowest, hippocampal MR binding is submaximal, whereas when corticosterone levels are at their circadian peak, hippocampal MR binding is maximal. In the present experiments the relationship between circadian rhythms of susceptibility to kainic acid-induced convulsions and plasma Corticosterone levels was investigated. In addition, the effects of exogenously administered Corticosterone and the MR antagonist spironolactone were examined at times of different convulsion susceptibility. In general, lower plasma Corticosterone levels were associated with decreased convulsion susceptibility and higher plasma Corticosterone levels were associated with greater convulsion susceptibility. Corticosterone, administered when endogenous levels were low, had a proconvulsant effect. Spironolactone, administered when Corticosterone levels were higher and hippocampal MR were presumably maximally occupied, had an anticonvulsant effect. These results indicate that the circadian rhythm in susceptibility to kainic acid-induced convulsions is sensitive to manipulations of Corticosterone levels and MR binding. Degree of central MR occupancy may, in part, mediate convulsion susceptibility in humans as well as laboratory animals.
Modeling of the Saturation Characteristics of High Voltage Transistors

The conventional Ebers-Moll model does not provide an accurate representation of the saturation region characteristics for transistors with a high resistivity collector region. Accurate one-dimensional calculations of device characteristics indicate that the size of the effective collector resistance is modulated at high currents by the extension of the neutral base into the collector region. Based on this analysis, a non-linear collector resistance is added to the Ebers-Moll equivalent circuit model to provide a more accurate representation of the characteristics in the saturation region.
Editorial: Functional intracellular renin-angiotensin systems: potential for pathophysiology of disease

the renin-angiotensin system (RAS) is a coordinated hormonal cascade playing a major role in cardiovascular, renal, and adrenal homeostasis ([4][1]). Derangements in the RAS have been implicated in the pathogenesis of many disease states, including hypertension and of target organ damage related to
Long-term medical complications after traumatic spinal cord injury: A regional model systems analysis

Abstract Objective: To analyze the incidence, risk factors, and trends of long-term secondary medical complications in individuals with traumatic spinal cord injury. Design: Data were reviewed from the National SCI Statistical Center on annual evaluations performed at 1, 2, 5, 10, 15, and 20 years after injury on patients injured between 1973 and 1998. Setting: Multicenter Regional SCI Model Systems. Main Outcome Measures: Secondary medical complications at annual follow-up years, including pneumonia/atelectasis, autonomic dysreflexia, deep venous thrombosis, pulmonary embolism, pressure ulcers, fractures, and renal calculi. Results: Pressure ulcers were the most frequent secondary medical complications in all years, and individuals at significant ( p p Conclusions: Pressure ulcers, autonomic dysreflexia, and pneumonia/atelectasis were the most common long-term secondary medical complications found at annual follow-ups. Risk factors included complete injury, tetraplegia, older age, concomitant illness, and violent injury.
Boiling thermal hydraulic analysis of multichannel low flow

Abstract Internal circulation occurs in a multi-channel system when the flow is heated non-uniformly causing natural convection currents. This paper describes a quasi-steady state approach for obtaining the flow distribution among the various channels over a wide range of transients. A unique solution is sought in the stable regime for single or two-phase coolant. The two sample cases discussed are: (1) bulk heating and boiling in an isolated reactor core, and (2) flow reversal in a reactor core.
Selectors: High-Level Resource Schedulers

Resource sharing problems can be described in three basically independent modular components. ? The constraints the resource places upon sharing because of physcal limitations and consistency requirements. ? The desired ordering of resource requests to achieve efficiency-either efficiency of resource utilization or efficiency of processes making the requests. ? Modifications to the ordering to prevent starvation of processes waiting for requests which might otherwise never receive service. A high-level nonprocedural language to specify these components of resource sharing problems is described. General deadlock and starvation properties of selectors are proven. Solutions to several classic resource sharing problems are shown to illustrate the expressiveness of this language. Proof techniques for this high-level language are introduced to show how to prove particular selectors are or are not deadlock and starvation free.
Academically Talented Students' Achievement in a Flexibly Paced Mathematics Program.

Thirdthrough sixth-grade mathematically talented students (n = 306) enrolled in a flexibly paced mathematics course made achievement gains far beyond the normative gains expected over a one-year period. When compared to students several grade levels higher, these highly able students gained as much as 46 percentile points from preto posttesting. Above-grade-level testing revealed that the students possessed a wide range of mathematics knowledge prior to entering the course with some students scoring at exceptionally high levels. With an individualized learning pace, some students as young as fourth grade completed the arithmetic/prealgebra sequence in their first year and returned the second year to successfully complete the beginning algebra sequence. Restricting such students to a rigid instructional pace and a "grade-appropriate" curriculum may place them at risk for declines in motivation and achievement.
The role of protein kinase C α and ε isozymes in DNA synthesis induced by muscarinic receptors in a glial cell line

Acetylcholine has been shown to induce proliferation of human astrocytoma cells by activating muscarinic receptors, particularly the m3 subtype. In the present study the role of protein kinase C in DNA synthesis induced by carbachol has been investigated. Carbachol-induced [methyl-3H]thymidine incorporation was inhibited by the protein kinase C inhibitors GF 109203X and staurosporine. However, carbachol-induced DNA synthesis was only partially reduced by protein kinase C down-regulation by phorbol 12-myristate 13-acetate (PMA), and maximal concentrations of carbachol and PMA had an additive effect on [methyl-3H]thymidine incorporation. Exposure for 24 h to maximally effective concentrations of carbachol did not induce down-regulation of protein kinase C alpha, and caused a small but significant down-regulation of protein kinase C epsilon; cells exposed for 24 h to carbachol were still able to respond with protein kinase C translocation to PMA stimulation. Carbachol caused a significant increase of phorbol ester binding, but did not stimulate protein kinase C alpha translocation, while it caused a short-lasting translocation of protein kinase C epsilon; however, protein kinase C epsilon translocation was not correlated with the time-course of carbachol-induced increase in [methyl-3H]thymidine incorporation. On the other hand, the time-course of translocation/down-regulation of protein kinase C alpha and protein kinase C epsilon induced by PMA was in good correlation with the time-course of PMA-induced [methyl-3H]thymidine incorporation. These results suggest that protein kinase C alpha may not be involved in DNA synthesis induced by muscarinic receptors stimulation in 132-1N1 astrocytoma cells, while protein kinase C epsilon appears to play a role in the initial exit from G0/G1 phase, though it cannot be considered the major determinant for sustained proliferation.
Electromechanical potentials in cortical bone—II. Experimental analysis

Abstract The electrokinetic model developed in Part I of this paper is used to characterize the electromechanical effect in cortical bone. Low frequency characteristics of stress-generated potentials are measured to provide insight into the origin and generation of these potentials induced in fluid-filled cortical bone. The results support the proposed model and indicate that fluid movement within the microporosity of bone is responsible for observed potentials whose origin is electrokinetic. The microporosity in bone, composed of the fluid spaces in and around mineral crystals encrusting collagen fibrils, constitutes an enormous surface area and appears to dominate surface-related phenomena at low frequencies. Previous experimental results, reported by many researchers, are also supported by this mechanism.
Geographical segregation and IL-6: a marker of chronic inflammation in older adults

Aim: To examine environmental sociodemographic risks of high IL-6, a marker of chronic inflammation in older adults. Methods: We spatially linked 1990 USA Census tract demographic and economic measures to a prospective cohort study of representative community residents aged 71 years and older, from over 1700 of whom a cytokine protein and biological marker of chronic inflammation, IL-6, was collected. Using generalized interactive mixed models, we modeled 1989–1990 individual and census level risk factors for the dependent variable high IL-6 between 1992–1993 (high IL-6 = upper quartile: >2.96 pg/ml). Results: After individual health risk adjustment, IL-6 remained elevated in communities with greater densities of poor older adults (odd ratio [OR]: 1.25 per 10% increase in exposure, 95% confidence interval [CI]: 1.05, 1.48) and in racially segregated communities (OR: 1.14 per 10% increase in exposure, 95% CI: 1.04, 1.25). Conclusions: Socially disadvantaged environments may influence IL-6, a biomarker of a...
grp (chk1) replication-checkpoint mutations and DNA damage trigger a Chk2-dependent block at the Drosophila midblastula transition.

The 13 syncytial cleavage divisions that initiate Drosophila embryogenesis are under maternal genetic control. The switch to zygotic regulation of development at the midblastula transition (MBT) follows mitosis 13, when the cleavage divisions terminate, transcription increases and the blastoderm cellularizes. Embryos mutant for grp , which encodes Checkpoint kinase 1 (Chk1), are DNA-replication-checkpoint defective and fail to cellularize, gastrulate or to initiate high-level zygotic transcription at the MBT. The mnk (also known as loki ) gene encodes Checkpoint kinase 2 (Chk2), which functions in DNA-damage signal transduction. We show that mnk grp double-mutant embryos are replication-checkpoint defective but cellularize, gastrulate and activate high levels of zygotic gene expression. We also show that grp mutant embryos accumulate DNA double-strand breaks and that DNA-damaging agents induce a mnk- dependent block to cellularization and zygotic gene expression. We conclude that the DNA-replication checkpoint maintains genome integrity during the cleavage divisions, and that checkpoint mutations lead to DNA damage that induces a novel Chk2-dependent block at the MBT.
Effect of the Active Site D25N Mutation on the Structure, Stability, and Ligand Binding of the Mature HIV-1 Protease

All aspartic proteases, including retroviral proteases, share the triplet DTG critical for the active site geometry and catalytic function. These residues interact closely in the active, dimeric structure of HIV-1 protease (PR). We have systematically assessed the effect of the D25N mutation on the structure and stability of the mature PR monomer and dimer. The D25N mutation (PRD25N) increases the equilibrium dimer dissociation constant by a factor >100-fold (1.3 ± 0.09 μm) relative to PR. In the absence of inhibitor, NMR studies reveal clear structural differences between PR and PRD25N in the relatively mobile P1 loop (residues 79-83) and flap regions, and differential scanning calorimetric analyses show that the mutation lowers the stabilities of both the monomer and dimer folds by 5 and 7.3 °C, respectively. Only minimal differences are observed in high resolution crystal structures of PRD25N complexed to darunavir (DRV), a potent clinical inhibitor, or a non-hydrolyzable substrate analogue, Ac-Thr-Ile-Nle-r-Nle-Gln-Arg-NH2 (RPB), as compared with PR·DRV and PR·RPB complexes. Although complexation with RPB stabilizes both dimers, the effect on their Tm is smaller for PRD25N (6.2 °C) than for PR (8.7 °C). The Tm of PRD25N·DRV increases by only 3 °C relative to free PRD25N, as compared with a 22 °C increase for PR·DRV, and the mutation increases the ligand dissociation constant of PRD25N·DRV by a factor of ∼106 relative to PR·DRV. These results suggest that interactions mediated by the catalytic Asp residues make a major contribution to the tight binding of DRV to PR.
Control of cytoskeletal mechanics by extracellular matrix, cell shape, and mechanical tension

We have investigated how extracellular matrix (ECM) alters the mechanical properties of the cytoskeleton (CSK). Mechanical stresses were applied to integrin receptors on the apical surfaces of adherent endothelial cells using RGD-coated ferromagnetic microbeads (5.5-microns diameter) in conjunction with a magnetic twisting device. Increasing the number of basal cell-ECM contacts by raising the fibronectin (FN) coating density from 10 to 500 ng/cm2 promoted cell spreading by fivefold and increased CSK stiffness, apparent viscosity, and permanent deformation all by more than twofold, as measured in response to maximal stress (40 dyne/cm2). When the applied stress was increased from 7 to 40 dyne/cm2, the stiffness and apparent viscosity of the CSK increased in parallel, although cell shape, ECM contacts, nor permanent deformation was altered. Application of the same stresses over a lower number ECM contacts using smaller beads (1.4-microns diameter) resulted in decreased CSK stiffness and apparent viscosity, confirming that this technique probes into the depth of the CSK and not just the cortical membrane. When magnetic measurements were carried out using cells whose membranes were disrupted and ATP stores depleted using saponin, CSK stiffness and apparent viscosity were found to rise by approximately 20%, whereas permanent deformation decreased by more than half. Addition of ATP (250 microM) under conditions that promote CSK tension generation in membrane-permeabilized cells resulted in decreases in CSK stiffness and apparent viscosity that could be detected within 2 min after ATP addition, before any measurable change in cell size. Permanent deformation only decreased after 20 min, once the CSK lattice had physically contracted. Importantly, regardless of cell shape or membrane continuity, CSK stiffness increased in direct proportion to the applied stress, as predicted by tensegrity (tensional integrity) cell models. These results suggest that the effects of ECM on CSK mechanics are not due to changes in osmotic or hydrostatic pressures. Rather, ECM alters CSKstiffness and apparent viscosity by binding integrins, promoting formation of molecular links with the CSK, transmitting mechanical stresses across these linkages, and inducing structural rearrangements within a continuous, tensionally integrated CSK lattice. In contrast, permanent deformation in the CSK appears to be more tightly coupled to cell extension and depends on both passive plasticity and dynamic remodeling events.
Acinetobacter infections – Epidemiology and pathogenesis of a significant healthcare-associated pathogen

The genus Acinetobacter contains a heterogeneous array of environmental and commensal organisms. The majority of these strains are non-pathogenic; however, A. baumannii has emerged as a common nosocomial pathogen. Groups with the highest risk of A. baumannii infection include immunocompromised and critically ill patients, and those undergoing long-term care following severe burns or traumatic injury. In these patients A. baumannii can cause wound infections, pneumonia, and sepsis resulting in prolonged recovery time, longer hospital stays, and in some cases can be a contributing factor in mortality. The rise to prominence of A. baumannii in the healthcare setting can be attributed to intrinsic resistance to desiccation and chemical disinfectants, which allow the organism to persist on surfaces. This persistence provides a constant reservoir for transmission and can result in recurrent outbreaks within hospital units. Additionally, numerous native antibiotic resistance mechanisms along with the evolution of novel resistance through mutation or horizontal gene transfer has resulted in multi-drug resistant (MDR) strains which demonstrate resistance to nearly every available class of antibiotic. While the development of new antibiotics such as tigecycline holds some promise for treating these resistant strains, the best interventional strategy is to prevent nosocomial spread through the use of screening, contact isolation and good hand hygiene practices.
The Effects of the 1980, 1981, and 1982 Tax Laws on Texas Rice Farmers

A whole farm Monte Carlo simulation model was used to simulate a typical rice farm on the Texas Gulf Coast for 10 years under the 1980, 1981, and 1982 income tax provisions. Results for this analysis indicate that the 1981 tax provisions clearly were more beneficial to farm operators than the 1980 or 1982 income tax provisions. While the 1981 and 1982 tax law changes clearly improved the cash flow of farm operators, they did not greatly improve the wealth positions of farm operators in the Texas Gulf Coast.
Towing dynamics of a liferaft and fast rescue craft in a surface wave

Abstract The equations of motion for the coupled dynamics of a small liferaft and fast rescue craft in a surface wave are formulated in two dimensions using the methods of Kane and Levinson [1985. Dynamics: Theory and Applications. McGraw-Hill Inc., New York]. It is assumed that the motion normal to the wave surface is small and can be neglected, i.e. the bodies move along the propagating wave profile. The bodies are small so that wave diffraction and reflection are negligible. A Stokes second order wave is used and the wave forces are applied using Morison's equation for a body in accelerated flow. Wind loads are similarly modelled using drag coefficients. The equations are solved numerically using the Runge–Kutta routine “ode45” of MATLAB ® . The numerical model provides guidelines for predicting the tow loads and motions of small craft in severe sea states.
The effects of a caffeine-containing beverage on neuromuscular performance during a multi-joint, lower body power exercise

Background Current research has shown varied results when comparing the effects of caffeinated beverages on explosive exercise movements. We hypothesized that lower body muscular explosiveness would be significantly increased (p < 0.05) after Redline ® energy drink ingestion versus a similar placebo (PLB) drink in recreationally active subjects (n=16). Methods After a day of dietary control and caffeine abstinence, otherwise-fasted participants performed four separate, strict squat jumps (SJ) under both conditions 48 – 96 hours apart. The variables measured included peak power (POW), peak force (FOR), peak velocity (VEL), maximal displacement (DSP), and maximal rate of force development (RFD) in the SJ for both Redline ® energy drink and