cssi/SciSciGPT-SciSciNet huggingface dataset:
Chapter 6 Reperfusion injury after stroke: neurovascular proteases and the blood–brain barrier

Publisher Summary This chapter surveys the profiles of cerebral blood flow and tissue injury during reperfusion, examines the pathophysiology of free radicals and inflammation, and presents a case for the central involvement of neurovascular proteases in disrupting blood–brain barrier function. During acute reperfusion, these proteases may be deleterious, whereas in the delayed phases they may mediate potentially beneficial neurovascular remodeling. Emerging data supports this hypothesis because clinical biomarkers, such as matrix metalloproteinases, have been linked with stroke risk, severity, and responses to thrombolysis. After certain periods of ischemia, reopening the blood vessels may not always lead to patent blood flow. These pockets of persistent occlusion at the microvascular level may then result in further brain injury. Oxidative stress occurs very early after onset of ischemia/reperfusion injury via overproduction of reactive oxygen species, and oxidative damage to lipid-rich membranes in the blood–brain barrier leads to vascular leakage and rupture in ischemic brain tissue. The neurovascular unit provides a conceptual model that can potentially unify the multiple interactions between these elements. A careful delineation of these molecular triggers and mediators should provide new therapeutic targets for this extremely important problem. Proteomic screening of clinical samples may identify targets of therapeutic intervention for in-depth evaluation.
Interactive visual cluster detection in large geospatial datasets based on dynamic density volume visualization

The emerging spatial big data (e.g. detailed spatial trajectories, geo-referenced social media data) provide tremendous opportunities for GIScientists and geographers. However, their large volume also poses challenges to existing spatial data analytical techniques (including visual analytical techniques). This article presents an interactive visual approach to detect clusters from those emerging data sets based on dynamic density volume visualization in a three-dimensional space (two spatial dimensions plus a third temporal or thematic dimension of interest). Cluster can be visually discovered through dynamic adjustment of density to colour/opacity mapping and extracted through flexible selection tools. The approach was tested on a large simulated data-set and a spatial trajectory data-set. The results show that the approach can overcome the visual clotting problem in traditional visualization tools caused by large data volume and facilitate the involvement of domain knowledge in analysis. It can effectiv...
Effect of Persistent Fibroma Virus Infection on Susceptibility of Cells to Other Viruses

Shope fibroma virus establishes a persistent cytoplasmic infection in primary (RK) and serially cultivated (DRK3) rabbit kidney cells which is accompanied by a morphological alteration of the cells. The response of such cells to superinfection by other viruses was compared with that of control cells by determining plaque production and virus yield of superinfecting viruses. It was found that the growth of other poxviruses, myxoma and vaccinia, was greatly inhibited in the fibroma virus-infected cells, but that of pseudorabies and herpes simplex viruses, which are unrelated deoxyribonucleic acid viruses, was virtually unaffected. The ribonucleic acid (RNA) viruses, poliovirus 1 and coxsackievirus B1, did not produce plaques on either RK or fibroma virus-infected (F-RK) monolayers. However, the growth of several other RNA viruses, vesicular stomatitis virus, encephalomyocarditis virus, Sindbis virus, and Newcastle disease virus, was enhanced in F-RK cells. None of these latter RNA viruses produced any infectious progeny in DRK3 cells, but they all plaqued on and produced good yields in DRK3 cells persistently infected with fibroma virus. This phenomenon is termed facilitation. Facilitation results from the infection of DRK3 cells by fibroma virus. Neither interference nor facilitation were due to changes in the adsorption or eclipse of the superinfecting virus.
Plasma Carotenoids Are Biomarkers of Long-Term High Vegetable Intake in Women with Breast Cancer

We investigated predictors of change in plasma carotenoids from baseline to 3 y and examined plasma carotenoid concentrations at 1 and 3 y in response to a high vegetable diet. Participants were 56 women diagnosed with breast cancer and enrolled in a randomized feasibility study for a trial examining the effect of a diet high in vegetables and fruits on the risk of breast cancer recurrence. Independent t test analysis revealed that the intervention group had significantly higher vegetable and fruit servings and fiber at 12 mo and significantly higher vegetable servings at 36 mo compared with the control group (P < 0.05). Energy intake from fat was significantly lower in the intervention group at 12 and 36 mo. The intervention group had significantly higher consumption of beta-carotene, alpha-carotene, lutein and beta-cryptoxanthin at 12 mo (P < 0.05). beta-Carotene, alpha-carotene and lutein intakes also were significantly higher at 36 mo (P < 0.05). At 36 mo, the intervention group had significantly higher plasma concentrations of alpha-carotene and beta-carotene compared with the control group. Repeated-measures ANOVA revealed that the intervention group had significantly increased (P < 0.05 with Bonferroni correction) plasma beta-carotene, alpha-carotene, lutein and lycopene concentrations at 12 and 36 mo compared with baseline. Baseline carotenoid concentrations were significantly inversely predictive (P < 0.05) of plasma carotenoid change. In addition, change in body mass index (BMI) and plasma cholesterol concentrations were predictive of plasma carotenoid change from baseline to 3 y. Results of this study demonstrate that change in plasma carotenoid concentrations is associated with change in BMI, change in plasma cholesterol and baseline carotenoid concentrations. Plasma carotenoid response can be an indicator of long-term high vegetable intake for women at risk of breast cancer recurrence.
Multicenter Experience of Technetium Pyrophosphate Scanning for Diagnosing TTR Cardiac Amyloid: A Revival in Nuclear Cardiology

Background: Cardiac dysfunction is a factor that influences candidate selection for kidney transplantation.There is a paucity ofdata regardingpredictors ofmyocardial recovery following kidney transplantation as well as long-term outcomes. Objectives: The purpose of this study was to identify the extent of reverse remodeling as well as predictors of such changes, and assess outcomes in our kidney transplant population. Methods: We reviewed 232 consecutive patients who underwent kidney transplantation at the Cleveland Clinic from 2003 to 2013 and had baseline and post-transplant echocardiogram, excluding those with simultaneous heart transplantation. Results: Post-transplant left ventricular ejection fraction (LVEF) improved in those with mild LV dysfunction (from 41 to 50%, p !0.0001, n 5 66) in addition to those with moderate LV dysfunction (from 32 to 47%, p!0.0001, n5 28). There was significant improvement in other parameters including diastolic function, LV diastolic dimension, LV mass, and right ventricular systolic pressure. After adjusting for multiple clinical variables, increased hemoglobin following transplantation was associated with improved LVEF (OR 1.50, 95% CI 1.07-2.14, p 5 0.016), and reduced mortality (HR 0.67, 95% CI 0.500.88, p 5 0.004). Pre-transplant LVEF was not associated with worse survival when adjusted for post-transplant LVEF (HR 0.82, 95% CI 0.65-1.05, p 5 0.118). Conclusions: Kidney transplantation is associated with improved cardiac structure and function. A rise in post-transplant hemoglobin was a significant factor associated with such changes, in addition to conferring a survival advantage. When adjusted for post-transplant LVEF, baseline cardiac dysfunction was not associated with excess mortality. These factors should be taken into account when assessing candidacy for kidney transplantation, and studies should further attempt to determine the role of anemia and other variables in the reverse remodeling observed in this population.
A Study of the Structural Elements of the French Language

Arthur's Summary— A scientific investigation of the relation between pronunciation and spelling in modern French as evidenced by detailed comparison of the elements of letter and sound frequency counts, supplementing recent studies leading to word, verb and idiom counts.)
Cognitive Pathways: Analysis of students' written texts for science understanding

The purpose of this study was to reconstruct writers' reasoning process as reflected in their written texts. The codes resulting from the text analysis were related to cognitive operations, ranging from simple to more sophisticated ones. The sequence of the cognitive operations as the text unfolded represents the writer's cognitive pathway at the time the text was produced. This type of analysis was used to study the impact that three different types of inquiries had on the reasoning process of low‐achieving and high‐achieving students when performing their laboratory activity using the Science Writing Heuristic. The researchers found that the reasoning pathways for both low‐achieving and high‐achieving students were similar for each type of inquiry, characterized as being decision‐making, descriptive/speculative, and application. The reasoning pathways for the decision‐making and application inquiries appear to be more structured than the pathways for the descriptive/speculative activity. The dependence ...
Normalization Method for Transcriptional Studies of Heterogeneous Samples - Simultaneous Array Normalization and Identification of Equivalent Expression

Normalization is an important step in the analysis of microarray data of transcription profiles as systematic non-biological variations often arise from the multiple steps involved in any transcription profiling experiment. Existing methods for data normalization often assume that there are few or symmetric differential expression, but this assumption does not always hold. Alternatively, non-differentially expressed genes may be used for array normalization. However, it is unknown at the outset which genes are non-differentially expressed. In this paper we propose a hierarchical mixture model framework to simultaneously identify non-differentially expressed genes and normalize arrays using these genes. The Fisher"s information matrix corresponding to array effects is derived, which provides useful intuition for guiding the choice of array normalization method. The operating characteristics of the proposed method are evaluated using simulated data. The simulations conducted under a wide range of parametric configurations suggest that the proposed method provides a useful alternative for array normalization. For example, the proposed method has better sensitivity than median normalization under modest prevalence of differentially expressed genes and when the magnitudes of over-expression and under-expression are not the same. Further, the proposed method has properties similar to median normalization when the prevalence of differentially expressed genes is very small. Empirical illustration of the proposed method is provided using a liposarcoma study from MSKCC to identify genes differentially expressed between normal fat tissue versus liposarcoma tissue samples.
Ion-induced phase formation in metal-metal and metal-silicon thin film structures

Abstract The phase formation in metals by using ion mixing techniques has been studied and compared with silicide formation. Upon irradiation of AlPt, AlNi and AlPd thin films, only the simplest intennetallic compounds of NiAl and PdAl were formed in crystalline structure, while the amorphous phase has been observed over a large range of composition. Ion mixing of AuCu bilayers resulted in the formation of substitutional solid solutions with no trace of ordered compounds. The formation of the ordered compound CuAu was achieved either by irradiation of bilayers with Ar ions at elevated substrate temperature or by irradiation of the mixed layers with He ions at relatively low temperature. In the AuAl system several crystal compounds existed in the as-deposited samples. These phases remained crystalline or transformed into other equilibrium compounds upon ion irradiation. The results suggest that the phase formation by ion mixing is dependent on the high quench rate in the collision cascade region and the atomic mobility at the irradiation temperature. The argument can be applied to silicide forming systems. With near-noble metals, the mixed atoms are mobile and form metallurgically distinct phases. With refractory metals, no equilibrium compounds are formed due to the lack of atomic mobility.
Cropping systems for clay soil : irrigated and nonirrigated soybean rotated with corn and sorghum

In the Mississippi River alluvial plain, soybean [Glycine max (L.) Merr.] is the primary crop. Seed yields of soybean grown under monocultured, dryland conditions in this region are usually lower than needed for profitable production. Experiments were conducted from 1985 through 1990 on Tunica clay (clayey over loamy, montmorillonitic, nonacid, thermic Vertic Haplaquept) near Stoneville, Mississippi, to determine the response of soybean to rotation with corn (Zea Mays L.) and sorghum [Sorghum bicolor (L.) Moench] under irrigated (I) and nonirrigated (NI) conditions
AROMATICITY AS A QUANTITATIVE CONCEPT. 7. AROMATICITY REAFFIRMED AS A MULTIDIMENSIONAL CHARACTERISTIC

Recent claims that linear relationships exist between energetic, geometric, and magnetic criteria of aromaticity are shown to be invalid for any representative set of heteroaromatics in which the number of heteroatoms varies.
On use of Bayesian statistics to make the Guide to the Expression of Uncertainty in Measurement consistent

The International Organization for Standardization (ISO) Guide to the Expression of Uncertainty in Measurement is being increasingly recognized as a de facto international standard. The ISO Guide recommends a standardized way of expressing uncertainty in all kinds of measurements and provides a comprehensive approach for combining information to evaluate that uncertainty. The ISO Guide supports uncertainties evaluated from statistical methods, Type A, and uncertainties determined by other means, Type B. The ISO Guide recommends classical (frequentist) statistics for evaluating the Type A components of uncertainty; but it interprets the combined uncertainty from a Bayesian viewpoint. This is inconsistent. In order to overcome this inconsistency, we suggest that all Type A uncertainties should be evaluated through a Bayesian approach. It turns out that the estimates from a classical statistical analysis are either equal or approximately equal to the corresponding estimates from a Bayesian analysis with non-informative prior probability distributions. So the classical (frequentist) estimates may be used provided they are interpreted from the Bayesian viewpoint. The procedure of the ISO Guide for evaluating the combined uncertainty is to propagate the uncertainties associated with the input quantities. This procedure does not yield a complete specification of the distribution represented by the result of measurement and its associated combined standard uncertainty. So the correct coverage factor for a desired coverage probability of an expanded uncertainty interval cannot always be determined. Nonetheless, the ISO Guide suggests that the coverage factor may be computed by assuming that the distribution represented by the result of measurement and its associated standard uncertainty is a normal distribution or a scaled-and-shifted t-distribution with degrees of freedom determined from the Welch–Satterthwaite formula. This assumption may be unjustified and the coverage factor so determined may be incorrect. A popular convention is to set the coverage factor as 2. When the distribution represented by the result of measurement and its associated standard uncertainty is not completely determined, the 2-standard-uncertainty interval may be interpreted in terms of its minimum coverage probability for an applicable class of probability distributions.
Encoding of novel figures for communication and memory

Abstract Descriptive names (encodings) were given to novel, graphic figures by S s under one of three instructions: social-communicative, self-memorial, or associative. Two weeks later these same S s plus a group of naive S s attempted to match their own encodings and those of another S from each of the groups with the correct figure. The memorial and social S s performed better on their own encodings than did the associative S s, and there was some indication that the memorial S s also performed better than the social S s. The social and memorial encodings were better communicators to others than the associative ones, but there was no difference between social and memorial encodings. The results were interpreted in terms of a communication model involving the criteria used for editing encodings and the availability of conventional labels for the stimuli.
Analytical models of GaAs FET's

We consider two analytical models for the calculation of the current-voltage characteristics of GaAs FET's. The first model which we call a "square law model" provides an accurate description of GaAs FETs with low pinchoff voltages (less than 2 V or so for GaAs devices with a 1-µm gate) and an approximate description of GaAs FETs with higher pinchoff voltages, The second model which we call a "complete velocity saturation" model accurately describes high pinchoff voltage devices (higher than 3 V or so for GaAs FETs with a 1-µm gate), but cosiderably overestimates the drain-to-source current in low pinchoff voltage FET's.
Photofrin-mediated photodynamic therapy for treatment of early stage laryngeal malignancies

To evaluate the efficacy of PHOTOFRINmediated photodynamic therapy (PDT) for the treatment of Tis-T1N0M0 squamous cell carcinoma (SqCCa) of the larynx in patients not amenable to or who failed conventional head and neck treatment. This is a retrospective study of 26 patients with early stage Tis-T1 SqCCa of the larynx treated with PHOTOFRIN-mediated PDT. Intravenous PHOTOFRIN (porfimer-sodium) (dose 2.0 mg/kg) was administered outpatient, followed by intraoperative photoactivation at 630 nm via fiberoptic microlens surface delivery (surgical light dose 50–100 J/cm2) 48–60 h later. As much as 16 out of 26 patients (62%) have demonstrated complete remission (average follow-up 40 months). There were 10 patients who were noted to have partial remission with recurrence observed 2–33 months subsequently retreated with either repeated PDT therapy or conventional therapy. PHOTOFRIN-mediated photodynamic therapy can be used as a primary modality to treat Tis-T1N0M0 tumors of the larynx or for treatment for those who have failed prior surgery and/or radiation therapy. PDT allows for preservation of function and structure to maintain or improve voice with absence of systemic toxicity. Patients may have multiple drug administrations and laser light retreatment for local disease control.
Phospholipid bicelles that align with their normals parallel to the magnetic field.

We have recently reported phospholipid bicelles (bilayered micelles) that have positive anisotropy of the magnetic susceptibility and align with their normals parallel to an external magnetic field [J. Am. Chem. Soc. 2001, 123, 1537]. Improvements have been made via the synthesis of a new phospholipid, 1-dodecanoyl-2-(4-(4-biphenyl)butanoyl)-sn-glycero-3-phosphocholine (DBBPC). Bicelles can be formed by mixing DBBPC with a short-chain phospholipid, 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC) in a ratio between 5.1:1 and 6.5:1 in an aqueous medium. The 31P NMR spectra clearly show that these bicelles align with their principal axes parallel to the magnetic field within a wide temperature range. The 31P chemical shifts indicate that the conformation of the polar headgroup in these bicelles may be different from that in common bicelles. The phase behavior of a mixture of DBBPC/DHPC with 6:1 mole ratio was investigated in the temperature range of 10−75 °C using 31P, 2H, and 23Na NMR. At lower temperatur...
Unit‐level time trends and seasonality in the rate of hospital‐acquired pressure ulcers in US acute care hospitals

This is a longitudinal study of the trend and seasonality in unit-level hospital-acquired pressure ulcer (HAPU) rates from 2004 to 2011, for 5447 acute care nursing units in 733 US hospitals. Unit-level HAPU rates decreased significantly during 2004�2007 (OR ¼ 0.91, 95% CI [0.90, 0.91]) and the decreasing trend was much stronger during 2008�2011 (OR ¼ 0.84 [0.83, 0.85]). Seasonal variations in HAPU rates were strong and consistent during 2004�2008, with the highest HAPU rate in Quarter 1 (Jan�Mar) and the lowest rate in Quarter 3 (Jul�Sep). During 2009�2011, the magnitude of this seasonality was greatly reduced, and only HAPU rate in Quarter 1 remained significantly higher than HAPU rates in other quarters.
Electromagnetic Field and Conduction Current Equivalence in the Lorentz and Coulomb Gauges

ABSTRACT Coulomb and Lorentz gauge equivalence of the electric and magnetic fields and the conduction current in the time and spectral domains is demonstrated. The analysis relies entirely on the Green's functions for both scalar and vector potentials in the two gauges, It is shown that the non-causal portion of the Coulomb gauge electric field expression is removed by the Coulomb gauge vector potential Green's function. The fact that the current is gauge invarient has important implications in the verification of electromagnetic field numerical codes based on integral equation methods.
Molecular imaging strategies for drug discovery and development

Recent advances in non-invasive molecular imaging provide exciting opportunities for discovery, validation and development of novel therapeutics. As the arsenal of detection devices and strategies, injectable probes, genetically encoded reporters and animal models rapidly expands, molecular imaging is becoming indispensable for drug discovery and development. Not only do such strategies reduce the time, cost and workload associated with conventional destructive end-point assays, but they also enable spatial and temporal monitoring of in vivo gene expression, signaling pathways, biochemical reactions and targets as they relate to the pharmacokinetics and pharmacodynamics of novel drugs.
In vivo Breast Cancer Characterization and Therapy Monitoring Using Diffuse Optical Methods Based on Endogenous Optical/Exogenous Fluorescence Contrast

Characterization of tumor-to-normal endogenous optical contrast from 3-D diffuse optical tomography, neoadjuvant chemotherapy monitoring with additional blood flow information, and 3-D fluorescence DOT with exogenous contrast agent injection are presented.
Quality-of-life outcomes of treatments for cutaneous basal cell carcinoma and squamous cell carcinoma.

Quality of life is an important treatment outcome for conditions that are rarely fatal, such as cutaneous basal cell carcinoma and squamous cell carcinoma (typically called nonmelanoma skin cancer (NMSC)). The purpose of this study was to compare quality-of-life outcomes of treatments for NMSC. We performed a prospective cohort study of 633 consecutive patients with NMSC diagnosed in 1999 and 2000 and followed for 2 years after treatment at a university-based private practice or a Veterans Affairs clinic. The main outcome was tumor-related quality of life 1 to 2 years after therapy, measured with the 16-item version of Skindex, a validated measure. Skindex scores vary from 0 (best) to 100 (worst) in three domains: Symptoms, Emotions, and Function. Treatments were electrodessication and curettage (ED&C) in 21%, surgical excision in 40%, and Mohs surgery in 39%. Five hundred and eight patients (80%) responded after treatment. Patients treated with excision or Mohs surgery improved in all quality-of-life domains, but quality of life did not improve after ED&C. There was no difference in the amount of improvement after excision or Mohs surgery. For example, mean Skindex Symptom scores improved 9.7 (95% CI: 6.9, 12.5) after excision, 10.2 (7.4, 12.9) after Mohs surgery, and 3.4 (−0.9, 7.6) after ED&C. We conclude that, for NMSC, quality-of-life outcomes were similar after excision and Mohs surgery, and both therapies had better outcomes than ED&C.
Wideband Cylindrical and Rectangular Dielectric Resonator Antennas

An investigation is conducted on increasing the bandwidth of dielectric resonator antennas by changing the radius-to-height and length-to-height ratios for cylindrical and rectangular geometries, respectively. A bandwidth of 30% is experimentally verified
Crisis and the Emergence of Charismatic Leadership in Groups: An Experimental Investigation1

Existing models of transformational change often highlight the charismatic attributes of leaders. Few approaches focus on the social preconditions which allow charismatic leadership processes to unfold. This research explores the notion that crisis is important to the emergence of charismatic leadership. The findings of a laboratory study indicate that crises foster the emergence of charismatic leaders who are then rated as more effective than group leaders who emerge in noncrisis situations. The implications for current conceptualizations of charismatic leadership processes and their role in frame-breaking organizational changes are discussed.
High-Resolution Electronic Spectra of 2-Hydroxy and 2-Aminopyridine. Perturbing Effects of the Nitrogen Atom in the Aromatic Ring

High resolution, rotationally resolved electronic spectra of 2-hydroxypridine (2HP) and 2-aminopyridine (2AP; at ∼277 and ∼299 nm, respectively) have been observed and fit using rigid-rotor Hamiltonians to within lifetime-limited resolutions of 170 and 120 MHz, respectively. The derived values of the rotational constants are very similar to those of phenol and aniline. However, 2HP and 2AP each exhibit inertial axis tilting, large rotations of their S 1 -S 0 electronic transition moments, and intramolecular hydrogen bonds, making them very different from their hydrocarbon analogues. Possible reasons for this behavior are discussed.
A new electrophoretic-autoradiographic method for the visual detection of phosphotransferases

Abstract In this paper we present the details of a slab acrylamide, lanthanum precipitation, autoradiographic technique and show it to be useful for the visualization of at least four different enzymes. We believe that with appropriate separation conditions and reaction mixtures this technique could be extended to a larger number of enzymes, theoretically all those whose isotopically labeled product could be specifically precipitated within the matrix of a polyacrylamide gel. It will be interesting to use this technique with other gel buffer systems, particularly those with a lower pH that have recently been reported (21). In addition, it might be useful to combine it with isoelectric focusing in slab gels (10). The technique would appear to be particularly useful for phosphotransferases and, to date, it has been applied to thymidine kinase and adenosine kinase with encouraging results. Work with other enzymes, and adapting the technique to starch gels, is also in progress.
Perspectives in the treatment of vascular dementia.

Abstract The diagnosis and treatment of vascular dementia (VaD) are particularly challenging because of its multiple causal lesions and the variety of its clinical presentations. Even poststroke dementia cases may be due to preexisting Alzheimer's disease. Diagnostic criteria for clinical trials have been implemented quite recently. Of the vasodilator agents, only the ergoloid mesylates have shown mild benefit. The calcium channel blocker nimodipine appears to be useful in subcortical VaD. Of the nootropic agents, memantine appears to be promising. Pentoxifylline produced significant improvement in multi-infarct VaD. Aspirin, triflusal and Ginkgo biloba extract were associated with some stabilization of dementia progression, perhaps due to their antiplatelet effects. Acetyl-cholinesterase inhibitors appear to be useful in improving memory and activities of daily living in VaD. Results of a large trial of donepezil in VaD should be available soon. Hyperbaric oxygen has been reported to be effective in Binswanger's disease. From the public health perspective, stroke prevention, particularly in atrial fibrillation, and the early and adequate treatment of arterial hypertension clearly decrease the incidence of VaD.
Successful Community College Transfer Students Speak Out

The community college as the entranceway into the baccalaureate degree is becoming a prevalent choice for students. This study was a qualitative approach to understanding attitudes, behaviors, and knowledge acquisition by successful community college transfer students. University students who transferred from a community college and were making successful progress toward completing the baccalaureate degree participated in focus groups to answer questions about the transfer process. Successful transfer students are highly motivated, persistent, engaged, believe they were well prepared by the community colleges for university junior level studies, and have recommendations for community colleges and universities in improving the transfer process.
CSMA/CD with network partitioning

Abstract One of the local area network medium access control standards created by the Institute of Electrical and Electronic Engineers in IEEE Project 802 is the carrier sense multiple access with collision detection (CSMA/CD. These studies show that control. Numerous studies have been reported in the literature on the performance of CSMA/CD. These studies show that CSMA/CD performs well under light network load but not well at heavy load. To improve the performance of CSMA/CD under heavy load, a new concept called network partitioning is presented. Network partitioning allows the network to be partitioned into segments when under heavy load. Partition stations then act as bridges between the segments. The impact of network partitioning on network performance was tested using a simulation model of an Ethernet local area network (an implementation of the CSMA/CD medium access control). The simulation results show that network partitioning can significantly improve the performance of CSMA/CD under heavy load.
Observation by spin-resolved resonant magnetotunneling of oscillatory Landé factor in two-dimensional electron systems

Abstract We have shown by magnetotunneling spectroscopy that at certain magnetic fields the Lande factor g of two-dimensional electrons is significantly enhanced relative to its three-dimensional value. The experiments were done using GaSbAlSbInAsAlSbGaSb heterostructures, in which a two-dimensional electron gas in the InAs layer is probed by holes from the GaSb electrodes tunneling in and out of it. The field dependence of the g factor is accounted for by the exchange interaction between electrons of the same spin.
Cardiac valvular chondroma.

Abstract The case of a 36-year-old woman with a tricuspid valvular tumor is presented. The lesion was successfully resected through the right atrium. Histologic examination showed a chondroma arising in a card ac valve.
A NEW PERSPECTIVE FOR SEMI-AUTOMATED STRUCTURAL VIBRATION CONTROL

The development of an innovative approach for optimum vibration suppression of flexible structures is presented. Utilizing concurrent use of semi-active and active subsections, an intelligent semi-automated alternative is suggested. By altering the adjustable structural properties (in semi-active unit) and control parameters (in active unit), a search is conducted to minimize an objective function subject to constraints, which may reflect performance characteristics. In practice, a user-in-the-loop interprets the resulting performance. A number of options may then be initiated: altering the parameters of the semi-active unit, or re-tuning the control parameters in the active unit, or concurrently adjusting the two. An essential component of this strategy is handling the parametric variations within the system. In order to increase the absorber efficiency against such variations an identification process is utilized in sequence with an optimization for re-tuning the absorber. The feasibility of the re-tuning procedure and performance improvement is demonstrated via simulations for a single-degree-of-freedom (s.d.o.f.) system. It is shown that concurrent adjustment of structural properties and control re-tuning significantly improves the vibration suppression quality.
Prostaglandin E2 inhibits B lymphocyte activation by a cAMP-dependent mechanism : PGE-inducible regulatory proteins

Abstract We have previously shown that macrophage-secreted prostaglandins of the E series (PGE) and other agents which increase cAMP inhibit IgM production and proliferation of murine B lymphocytes. In this study, we show that PGE2 inhibits B cell activation events including enlargement, class II MHC hyperexpression, and the expression of the low-affinity receptor for IgE, FcϵRII/CD23 (35-50%) in a cAMP-dependent manner. PGE action is mimicked by other cAMP-inducing agents and is inhibited by RpcAMP (a nonhydrolyzable cAMP analog which is a competitive inhibitor of cAMP-dependent protein kinase A). PGE2 could inhibit enlargement and upregulation of activation Ag even if preincubated with cells and then washed out prior to B cell stimulation. This change in B cell phenotype was abrogated if the reversible protein synthesis inhibitor cycloheximide was included during B cell incubation with PGE2. To identify the newly synthesized cAMP- and PGE-inducible regulatory proteins (PIRP), two-dimensional gel electrophoresis of lysates of B lymphocytes treated ± PGE2 was performed. This report is the first to identify putative PIRP proteins. The roles of PIRP in PGE regulation of B cell activation and class switching are discussed.
Coronary calcium: the case for helical computed tomography.

Summary:This article provides the rationale for using helical (aka spiral, conventional, and mechanical) computed tomography (CT) systems from measuring coronary calcium. The current state and active research concerning measuring coronary calcium with single-and multi-slice systems is reviewed. The
Effect of Infrared Transparency on the Heat Transfer Through Windows: A Clarification of the Greenhouse Effect

The various radiative, convective, and conductive components of the net heat transfer are calculated and illustrated for various infrared transparencies of covers such as would be used in architectural, greenhouse, or solar collector windows. It is shown that in the limiting cases of infrared opacity and infrared transparency the relative contributions of the three modes of heat transfer are altered, but all contribute significantly. The radiation shielding arguments pertain to the analogous green-house effect in the atmosphere.
The zebrafish as a novel animal model to study the molecular mechanisms of mechano-electrical feedback in the heart.

Abstract Altered mechanical loading of the heart leads to hypertrophy, decompensated heart failure and fatal arrhythmias. However, the molecular mechanisms that link mechanical and electrical dysfunction remain poorly understood. Growing evidence suggest that ventricular electrical remodeling (VER) is a process that can be induced by altered mechanical stress, creating persistent electrophysiological changes that predispose the heart to life-threatening arrhythmias. While VER is clearly a physiological property of the human heart, as evidenced by “T wave memory”, it is also thought to occur in a variety of pathological states associated with altered ventricular activation such as bundle branch block, myocardial infarction, and cardiac pacing. Animal models that are currently being used for investigating stretch-induced VER have significant limitations. The zebrafish has recently emerged as an attractive animal model for studying cardiovascular disease and could overcome some of these limitations. Owing to its extensively sequenced genome, high conservation of gene function, and the comprehensive genetic resources that are available in this model, the zebrafish may provide new insights into the molecular mechanisms that drive detrimental electrical remodeling in response to stretch. Here, we have established a zebrafish model to study mechano-electrical feedback in the heart, which combines efficient genetic manipulation with high-precision stretch and high-resolution electrophysiology. In this model, only 90 min of ventricular stretch caused VER and recapitulated key features of VER found previously in the mammalian heart. Our data suggest that the zebrafish model is a powerful platform for investigating the molecular mechanisms underlying mechano-electrical feedback and VER in the heart.
Studies of lysosomal sialic acid metabolism: retention of sialic acid by Salla disease lysosomes.

Abstract Purified rat liver lysosomes were incubated in 0.2 M sialic acid resulting in an increase in lysosomal free sialic acid of 3.8 ± 1.5 nmol /unit β hexosaminidase. Sialic acid loss by these lysosomes was stimulated 2–3 fold by 25 mM sodium phosphate. Loss of sialic acid by lysosomes from cultured human diploid fibroblasts was similar to that observed in rat liver lysosomes while loss of sialic acid by lysosomes from cultured fibroblasts from a patient with infantile Salla disease occurred much more slowly. Salla disease appears to be the consequence of defective lysosomal transport of sialic acid and is analagous to cystinosis, a disorder of lysosomal amino acid transport.
Cheap concurrency in C

This paper describes the implementation of a simple kernel providing concurrency for the C programming language1. The kernel provides services for process creation and termination, process synchronization, handling of interrupts, and mutual exclusion. It runs under UNIX2 (bsd 4.2) and is almost entirely implemented in C([2]).
Symmetry, Scale Types, and Generalizations of Classical Physical Measurement

A review is presented of a number of recent results concerning fundamental measurement structures with a particular emphasis on generalizations of physical measurement. Relational structures are classified in terms of richness and redundancy of their automorphism groups (i.e., in terms of their symmetries). By means of this classification, the possible types of measurement scales are described, and the possibilities for structures with concatenation operations (either associative or nonassociative and either positive or intensive) and for conjoint structures whose automorphisms factor into component automorphisms are explicitly spelled out. Certain conjoint structures with concatenation operations on components are viewed as generalizations of classical physical measurement and some of their most important algebraic and representational properties are explored.
Conductivity and Hall Effect of ZnO at Low Temperatures

The Hall effect and conductivity of zinc oxide have been measured in dense polycrystalline samples and two single crystals.It has been found that the usual simple Wilson semiconductor model is inadequate for the proper interpretation of results. Several modifications and additions have been suggested for the usual single-level impurity semiconductor. Allowance has been made for the polycrystalline nature of the sintered specimens in deducing the bulk properties.Three models are successful in giving the correct interpretation for the experimental results of the Hall curves. These are: (1) orbital degeneracy of electrons attached to an interstitial zinc atom; (2) additional energy levels at traps at the impurity level, where the number of traps is much greater than the number of donors; (3) traps far below the donor level that greatly outnumber the donors [this is mathematically the same as (2) but necessitates other lattice imperfections for physical realization].Physical realization of these energy level schemes is considered in the light of the other physical properties of ZnO, such as luminescence and photoconductivity. These physical models are examined with the aid of present-day knowledge of the alkali halides and other ionic crystals. It is found that pairs of positive (zinc) plus negative (oxygen) ion vacancies with excess oxygen ion vacancies are capable of reproducing the diversified electrical and optical properties of zinc oxide semiconductor. The previous scheme of frozen-in interstitial zinc atoms is shown to be incompatible with our experimental results. Experiments are proposed for further verification of the proposed model.
Psychology's search for unity

Abstract Arguments for unifying psychology's disparate elements are examined in relation to the actualities of scientific practice. These arguments are often based on such implicit unexamined assumptions as: (1) psychology resembles physics conceptually and historically; (2) there is an underlying rational order to knowledge which will define and justify the direction unification will take; (3) there is a knowable reality independent of our perceptions; (4) the outcome of unification will resemble a harmonious family working for the common good of “knowledge” and “truth.” While these assumptions have plausibility, it is argued that alternative views have equally legitimate claims and if we accept them, the possibility of unifying psychology becomes more problematic. Psychology's desire for unification appears parallel to a similar yearning within society that seeks to counteract the fragmentation of social life and consciousness that characterizes modernity.
Floating-zone crystal growth with a heated ring covering the melt surface

Abstract Although free from gravity-induced natural convection, the melt zone in microgravity floating-zone crystal growth can still be subjected to strong, oscillatory thermocapillary convection. In order to help reduce thermocapillary convection, and meanwhile improve the cross-sectional control and surface quality of resultant crystals, the convectional floating-zone process has been modified. In this modified process a heated ring covers most of the surface of the melt zone. This process was studied using NaNo 3 as a test material. Single crystals were grown from 6 mm diameter cast rods of NaNO 3 using two different types of heated rings. It was observed that with one type of ring, wetting of the ring outer surface by the melt caused significant variations in the crystal cross-section. With the other type, however, this wetting problem did not occur and the resultant crystals exhibited a very uniform cross-section and smooth surface. Thermocapillary convection, instead of prevailing in the bulk melt zone as in conventional floating-zone crystal growth, was limited to near the free surface.
Interactions of Meaning and Syntax: Implications for Models of Sentence Comprehension.

Abstract A reduced relative—main clause ambiguity occurs in sentences that begin with reduced relative clauses, as in The hangman executed by the government was convicted of treason . This ambiguity has often been the focus of research designed to investigate the processes by which syntactic structures are built during sentence comprehension. Reading time differences between more difficult and less difficult reduced relative sentences (e.g., The hangman executed by the government was convicted of treason vs. The martyr executed by the government was convicted of treason ) have been interpreted as reflecting syntactic disambiguation processes. In this article, we point out that there exists a possible alternative interpretation of the differences, namely, that reading times are longer for the more difficult sentences because the information in their relative clauses mismatches a reader’s general knowledge of how events typically occur in the world or how they are typically referenced in discourse. Under this interpretation, the differences in reading times do not have their bases in disambiguation processing.
A Mastery Rubric: guiding curriculum design, admissions and development of course objectives

This article describes a ‘Mastery Rubric’ (MR) used to design both the curriculum and the assessments in a new two‐year certificate programme intended to train physicians in clinical research skills. The MR for clinical research skills is built around a set of core research skills: critical review of literature; articulation of research objective; development of research design; development of analysis plan; implementation of the study; implementation of the analysis plan and presentation of results. Four distinct levels of performance are described for each skill: beginning, novice, competent and proficient. This rubric outlines and provides a path to mastery of the clinical research skills the certificate programme was designed and funded to target. Using the rubric to design the curriculum ensures that courses will provide instruction in key domains, promotes assessment that demonstrates development in the target skills and knowledge, and encourages reflection and cognitive self‐monitoring in the stude...
Progress to-date - Vision for the future

DARPA's Advanced Space Technology Program (ASTP) encompasses the development and operation of the Pegasus (air-launched) and Taurus (standard small) launch vehicles and the 'lightsats' Microsat, Macsat, and Darpasat, as well as satellite subsystems, communications, optical-components, and submarine laser communication technology development programs. An assessment is made of the benefits derivable from these technologies by both the defense and civilian space communities.
Limiting behavior of ac conductivity in ionically conducting crystals and glasses: A new universality.

The ac conductivity \ensuremath{\sigma}(\ensuremath{\omega}) of three ionically conducting crystalline materials (${\mathrm{NaClZn}}^{2+}$, ${\mathrm{KTaO}}_{3}$:${\mathrm{Co}}^{3+}$,${\mathrm{H}}^{+}$, and ${\mathrm{CeO}}_{2}$:${\mathrm{Gd}}^{3+}$) and two glasses have been studied over an unusually wide temperature range. In all cases, limiting power-law behavior [exponent s=1 in \ensuremath{\sigma}(\ensuremath{\omega})=${\mathrm{\ensuremath{\sigma}}}_{0}$+A${\mathrm{\ensuremath{\omega}}}^{\mathit{s}}$] is observed at relatively low temperatures. It is concluded that this limiting behavior is a universal phenomenon. Available theoretical explanations have been examined and found to be unsatisfactory.
Transcriptional changes associated with reduced spontaneous liver tumor incidence in mice chronically exposed to high dose arsenic

Exposure of male C3H mice in utero (from gestational days 8-18) to 85ppm sodium arsenite via the dams' drinking water has previously been shown to increase liver tumor incidence by 2 years of age. However, in our companion study (Ahlborn et al., 2009), continuous exposure to 85ppm sodium arsenic (from gestational day 8 to postnatal day 365) did not result in increased tumor incidence, but rather in a significant reduction (0% tumor incidence). The purpose of the present study was to examine the gene expression responses that may lead to the apparent protective effect of continuous arsenic exposure. Genes in many functional categories including cellular growth and proliferation, gene expression, cell death, oxidative stress, protein ubiquitination, and mitochondrial dysfunction were altered by continuous arsenic treatment. Many of these genes are known to be involved in liver cancer. One such gene associated with rodent hepatocarcinogenesis, Scd1, encodes stearoyl-CoA desaturase and was down-regulated by continuous arsenic treatment. An overlap between the genes in our study affected by continuous arsenic exposure and those from the literature affected by long-term caloric restriction suggests that reduction in the spontaneous tumor incidence under both conditions may involve similar gene pathways such as fatty acid metabolism, apoptosis, and stress response.
Policy: NIH plans to enhance reproducibility

Francis S. Collins and Lawrence A. Tabak discuss initiatives that the US National Institutes of Health is exploring to restore the self-correcting nature of preclinical research.