cssi/SciSciGPT-SciSciNet huggingface dataset:
Exploring relationships between outdoor air particulate-associated polycyclic aromatic hydrocarbon and PM2.5: A case study of benzo(a)pyrene in California metropolitan regions

Polycyclic aromatic hydrocarbons (PAHs) and particulate matter (PM) are co-pollutants emitted as by-products of combustion processes. Convincing evidence exists for PAHs as a primary toxic component of fine PM (PM2.5). Because PM2.5 is listed by the US EPA as a “Criteria Pollutant”, it is monitored regularly at sites nationwide. In contrast, very limited data is available on measured ambient air concentrations of PAHs. However, between 1999 and 2001, ambient air concentrations of PM2.5 and benzo(a)pyrene (BaP) are available for California locations. We use multivariate linear regression models (MLRMs) to predict ambient air levels of BaP in four air basins based on reported PM2.5 concentrations and spatial, temporal and meteorological variables as variates. We obtain an R2 ranging from 0.57 to 0.72 among these basins. Significant variables (p<0.05) include the average daily PM2.5 concentration, wind speed, temperature and relative humidity, and the coastal distance as well as season, and holiday or weekend. Combining the data from all sites and using only these variables to estimate ambient BaP levels, we obtain an R2 of 0.55. These R2-values, combined with analysis of the residual error and cross validation using the PRESS-statistic, demonstrate the potential of our method to estimate reported outdoor air PAH exposure levels in metropolitan regions. These MLRMs provide a first step towards relating outdoor ambient PM2.5 and PAH concentrations for epidemiological studies when PAH measurements are unavailable, or limited in spatial coverage, based on publicly available meteorological and PM2.5 data.
EFFECTS OF LARGE VARIATIONS IN DIET ON FREE CATECHOLAMINES AND THEIR METABOLITES IN URINE

Abstract Urinary excretion of free catecholamines and their major metabolites was studied in seven normal young men while they were on three diets which were excessive, moderately restricted, or very low in catecholamine nad caffeine content. When results are expressed in relation to urinary creatinine, the most liberal diet increased normetanephrine ( NM ) and VMA excreation by about 30 per cent. Free epinerphrine ( E ) and metaphrine ( M ) excretion rates also increased by 40 per cent and 10 per cent, respectively, but the changes were not statistically significant. Changes in free norepinerphrine ( NE ) and free dopamine ( D ) excretion were small and did not approach statistical significance. When results are expressed as quantities excreted per day, the only statistically significant differene associated with diet was greater excretion of M during the moderately restricted diet. Intra-subject variation in estimated excretion and creatinine was arge, with a median coefficient of variation of 16 per cent. When amines and metabolites were expressed per unit of creatinine, intrasubject variance of metabolites was made smaller but variance of free amines was not. This “creatinine correction” tended to enhance the statistical significance of intersubject differences. The more liberal diets tended to increase intrasubject variance, particularly of E and NM . Variance of NE was least affected. Except for E and NM , where it was roughly equal to diet effects, intersubject variance was much greater than the diet effects. It is concluded that in studies of urinary NM and VMA , attention must be given to the NE content of the diet. In studies involving E and M , caffeine shoudl be proscribed or controlled. In the case of free NE , and probably of free D , no control appears to be necessary.
An empirical model of tropical ocean dynamics

To extend the linear stochastically forced paradigm of tropical sea surface temperature (SST) variability to the subsurface ocean, a linear inverse model (LIM) is constructed from the simultaneous and 3-month lag covariances of observed 3-month running mean anomalies of SST, thermocline depth, and zonal wind stress. This LIM is then used to identify the empirically-determined linear dynamics with physical processes to gauge their relative importance to ENSO evolution. Optimal growth of SST anomalies over several months is triggered by both an initial SST anomaly and a central equatorial Pacific thermocline anomaly that propagates slowly eastward while leading the amplifying SST anomaly. The initial SST and thermocline anomalies each produce roughly half the SST amplification. If interactions between the sea surface and the thermocline are removed in the linear dynamical operator, the SST anomaly undergoes less optimal growth but is also more persistent, and its location shifts from the eastern to central Pacific. Optimal growth is also found to be essentially the result of two stable eigenmodes with similar structure but differing 2- and 4-year periods evolving from initial destructive to constructive interference. Variations among ENSO events could then be a consequence not of changing stability characteristics but of random excitation of these two eigenmodes, which represent different balances between surface and subsurface coupled dynamics. As found in previous studies, the impact of the additional variables on LIM SST forecasts is relatively small for short time scales. Over time intervals greater than about 9 months, however, the additional variables both significantly enhance forecast skill and predict lag covariances and associated power spectra whose closer agreement with observations enhances the validation of the linear model. Moreover, a secondary type of optimal growth exists that is not present in a LIM constructed from SST alone, in which initial SST anomalies in the southwest tropical Pacific and Indian ocean play a larger role than on shorter time scales, apparently driving sustained off-equatorial wind stress anomalies in the eastern Pacific that result in a more persistent equatorial thermocline anomaly and a more protracted (and predictable) ENSO event.
Sub-units of Acid Phosphatase-1 in Drosophila melanogaster : Reversible Dissociation in vitro

THE genetic control of an acid phosphatase in the sibling species Drosophila melanogaster and D. simulans has been reported by one of us1. “Slow” and “fast” electrophoretic variants of this enzyme, called acid phosphatase-1 or Acph-1, are specified by codominant alleles, Acph-1A and Acph-1B, of a gene located very near the right end of chromosome 3 in each species. Zymograms of the heterozygotes (and interspecific hybrids) show three bands or zones of acid phosphataso activity: the “slow” and “fast” or Acph-1AA and Acph-1BB forms of the enzyme which are characteristic of the homozygous parents, and a third, more heavily staining zone which occupies a position between the parental enzymes.
The binding of contaminants to humin: A mass balance

Abstract A mass balance is presented for the distribution of bound contaminant residues of 3 PAHs and 2 PCBs between the organic matter fractions of 3 different soil types. The PAHs and PCBs show rapid binding to soil with maximum binding happening within the first 30 days of contamination. In all soils and contaminants studied humin contains more than 50% of the bound residue and typically between 70 and 80%. The humin is further fractionated by the methyl isobutyl ketone partitioning method into three additional fractions: 1) lipid, 2) bound-humic acid, and 3) the insoluble residue. This further fractionation shows that the bound-lipidfraction has an extremely high affinity for the contaminants.
Evaluation of techniques for sulfuric acid and particulate strong acidity measurements in ambient air

Abstract A laboratory and field study was conducted to evaluate measurement methods for sulfuric acid and strong acids in atmospheric aerosols. Selective extraction of H 2 SO 4 with benzaldehyde and titrimetry for strong acids were evaluated and compared using laboratory-generated mixtures of ≤ 0.3 μm diameter H 2 SO 4 , (NH 4 ) 2 SO 4 and NH 4 HSO 4 aerosols on clean and atmospheric particulate-loaded filters. Filter media were selected based on filtration efficiency and acid recovery with ≤ 0.3 μm H 2 SO 4 aerosols. An ammonia denuder was employed in field sampling together with removal of non-respirable particles, to increase the stability of H 2 SO 4 following collection. Simultaneous gas phase ammonia measurements were made to assist in interpreting the particulate sample results. The presence of atmospheric particulate matter was shown to reduce recoveries of laboratory-generated H 2 SO 4 sharply, but recoveries of total strong acid usually remained ≥ 60%. Anhydrous benzaldehyde was found to extract NH 4 HSO 4 to a substantial degree in the absence of atmospheric particulate matter. Samples collected in Pittsburg, California showed correlation between sulfuric acid and particulate strong acid measurements. As much as 0.6 μg m −3 H 2 SO 4 and 1.6 μg m −3 acidity, expressed as H 2 SO 4 , was found. However, on the basis of recovery studies we believe these represent lower limit values.
Nuclear protein import: specificity for transport across the nuclear pore.

Transport of proteins into the cell nucleus is thought to require specific localization sequences and may be mediated by nuclear pores. Following microinjection into fused cultured cells, nuclear protein import was directly monitored by fluorescence microscopy using B-phycoerythrin (PE; Mr 240,000) coupled to synthetic peptides corresponding to the simian virus 40 (SV-40) large T antigen nuclear localization signal. Peptides with a single amino acid replacement found in a cytoplasmic mutant of T antigen (cT) failed to promote uptake. Further studies with deletion peptides revealed the minimum sequence requirements for efficient nuclear import of PE conjugates to be similar to those previously defined genetically for large T antigen itself. No competitive inhibition of uptake was observed in cells expressing nuclear or cytoplasmic T antigen. Nuclear import was time- and temperature-dependent. The lectin wheat germ agglutinin (WGA) binds to glycoproteins bearing O-linked GlcNAc on the cytoplasmic face of the nuclear pore in vitro [J.A. Hanover et al. (1987) J. Biol. Chem. 262, 9887-9894] and in vivo. Microinjection of WGA into the cytoplasm of living cells did not alter the diffusion of dextran (Mr 10,000) into the nucleus, but blocked the uptake of PE conjugates. This inhibition was reversed when a competing saccharide was introduced into the cytoplasm.
Risk Decision Making and Seismic Risk Preparedness at North American Seaports: Analysis of a System-Wide Survey

Seaports are important drivers of regional economies, and many face seismic risks. This study examines whether and how North American seaports consider, have engaged in, or have the capacity to eff...
Enhancement of electrical conductivity in MgO due to lithium impurities

Abstract The electrical conductivity of lithium-doped MgO crystals at room temperature is shown to be enhanced by the thermal creation of stable [Li] 0 defects by oxidation at elevated temperatures. The current-voltage curves are found to be nonlinear at low voltages. The enhancement in conductivity is attributed to localized regions of high [Li] 0 concentration in which the holes at the [Li] 0 sites are thermally ionized into the valence band, causing these regions to be semiconducting.
Shivering and its cost during reproductive behaviour in Neotropical owl butterflies, Caligo and Opsiphanes (Nymphalidae: Brassolinae)

Abstract Abstract. Male owl butterflies Caligo and Opsiphanes were gathered during crepuscular hours along an edge habitat, where they engaged either other males of the same species in aerial encounters, or females in courtship and copulation. Shivering elevated thoracic temperature during crepuscular hours approximately 10°C above ambient temperature for Caligo and 15°C for Opsiphanes in phase with reproductive activities for both males and females. Male displays endured on average 30 min, and the estimated cost of maintaining an elevated body temperature during this time was 3 mg of fat for each bout. Owl butterflies are generally lethargic during daylight hours and rarely shivered and never basked in sunlight during these times. Owl butterflies shivered in ambient temperatures (24-26°C) that were well above the lower critical temperature for flight (19-20°C). Shivering did not elevate abdominal temperature, and hence the butterflies did not raise their temperature to make pheromones volatile from abdominal scent glands. By elimination of these alternative hypotheses, it was concluded that shivering to elevate thoracic temperature prepares owl butterflies for reproductive encounters.
The Radiopaque Surface Layer of Enamel and Caries

In 1934 Thewlis (1) made a radiographic study of ground sections of human teeth and described what he regarded as a hypercalcified outer layer. Hollander and Saper (2) considered this apparent radiopaque surface layer of the enamel as an artifact. In 1937 Thewlis (3) described microphotometer experiments indicating that the surface layer of the enamel is in fact hypercalcified. He found that there is "a steady increase in calcification from the amelodentinal junction outwards and the outer enamel layer is in many cases markedly hypercalcified. " Hollander and Saper (2) also noted that the radiopaque white line usually persisted on the surface of enamel over an area of decalcification corresponding to an early caries lesion. They concluded that this is also an artifact. Following this view the writer attached no significance to this line in grenz-ray studies of incipient caries lesions (4, 5, 6, 7). If the line is not an artifact, however, its significance needs investigation. Pincus pointed out the paradox of decalcification occurring in enamel under an apparently intact outer layer. He suggested that the radiographic effect is due to bacterial invasion of the organic matrix of enamel rather than to acid attack (8). To check up on the nature of the white line which persists on the surface of incipient caries lesions, the writer sent several grenz-ray negatives to Thewlis in England. He replied as follows:
Reproducibility of the French-American-British classification of acute leukemia: the southwest oncology group experience

After initial French-American-British (FAB) diagnosis by a multiinstitutional Southwest Oncology Group panel, slides of acute leukemia cases were recirculated to panel members for second review. The reproducibility of the FAB classification is analyzed. The classification is reproducible in the 70% range in panel reviewer hands and allows remarkable reproducibility in the morphologic and cytochemical distinction of acute lymphoid leukemia (ALL) from acute myeloid leukemia (AML). The limitations of a morphologic and cytochemical classification of acute leukemia are discussed. A simplification of the FAB system, merging M1, M2, and M4 as M7, is proposed; this simplification improves the system's reproducibility.
CONGESTED FREEWAY MICROSIMULATION MODEL USING VISSIM

A procedure for constructing and calibrating a detailed model of a freeway by using VISSIM is presented and applied to a 15-mi stretch of I-210 West in Pasadena, California. This test site provides several challenges for microscopic modeling: a high-occupancy vehicle (HOV) lane with an intermittent barrier, a heavy freeway connector, 20 metered on-ramps with and without HOV bypass lanes, and three interacting bottlenecks. Field data used as input to the model were compiled from two separate sources: loop detectors on the on-ramps and main line (PeMS) and a manual survey of on-ramps and off-ramps. Gaps in both sources made it necessary to use a composite data set, constructed from several typical days. FREQ was used as an intermediate tool to generate a set of origin-destination matrices from the assembled boundary flows. The model construction procedure consists of (1) identification of important geometric features, (2) collection and processing of traffic data, (3) analysis of the main-line data to ident...
Novel NOTCH1 mutations in patients with bicuspid aortic valve disease and thoracic aortic aneurysms.

Objectives Bicuspid aortic valve is a common condition and is associated with a significantly increased risk of developing thoracic aortic aneurysms and acute aortic dissection. Patient-specific prediction of the risk of developing thoracic aortic aneurysm, however, is imprecise. We hypothesize that genotypic variations in patients with bicuspid aortic valves contribute to this observed variability in aortic phenotype. We, therefore, investigated the potential relationship between mutations in regions of NOTCH1 recently reported to be associated with bicuspid aortic valve and the phenotype of bicuspid aortic valve and thoracic aortic aneurysms in unrelated patients undergoing surgical repair. Methods We performed a targeted mutational analysis of NOTCH1 using genomic DNA from 48 unrelated subjects with concomitant bicuspid aortic valve and thoracic aortic aneurysm using denaturing high-performance liquid chromatography and DNA sequencing. We focused on exons in which mutations associated with bicuspid aortic valve have been reported previously. Results were compared with control subjects with trileaflet aortic valves (n = 94), bicuspid aortic valves, and normal aortas (n = 22) and in subjects with tricuspid aortic valves and thoracic aortic aneurysms (n = 28). Results Four unique, nonsynonymous (3 novel) variants were identified in 5 (10.4%) of 48 patients with concomitant bicuspid aortic valves and thoracic aortic aneurysms compared with only 3 (2.1%) of 144 control subjects ( P = .02). Of these, 2 novel missense mutations, A1343V and P1390T, were observed only in patients with bicuspid aortic valves and tricuspid aortic aneurysms. Conclusions This targeted analysis involving NOTCH1 exons previously implicated in familial and sporadic bicuspid aortic valve demonstrates overrepresentation of NOTCH1 missense variants among patients with bicuspid aortic valves and thoracic aortic aneurysms. Identification of aneurysm-predisposing susceptibility genes may lead to gene-directed surgical therapy of the ascending aorta for patients with bicuspid aortic valves.
The effect of secretory leukocyte proteinase inhibitor (SLPI) in a murine model of asthma

Abstract Rationale Serine Leukocyte Proteinase Inhibitor (SLPI) is a naturally occurring protease that protects the epithelial surface of the lung against several serine proteases. There is little data available on the effect of recombinant SLPI on the markers of inflammation and airway hyperresponsiveness (AHR). Hypothesis SLPI therapy will reduce inflammation and AHR in ovalbumin-sensitized C57/Black 6 mice. Objective To assess the effect of SLPI therapy on markers of inflammation and AHR. Methods C57/Black 6 mice were sensitized with ovalbumin (OVA) and divided into two groups and received 1) 30 μg recombinant SLPI 2) no treatment. Normal mice were also maintained as additional controls. SLPI was administered once weekly for three weeks, via nebulization to sensitized mice, three days after an OVA challenge was given. The mice were sacrificed 24 hours after SLPI was given, and measurements of eosinophil peroxidase activity (EPO), peripheral blood eosinophils (EOS), lung histology, serum IgE, and AHR to methacholine (Mch) challenge were performed. Control groups were also sacrificed at the same time points. Data were analyzed to compare sensitized untreated group with the normal or sensitized treated group using the student t test. Results SLPI therapy significantly decreased AHR to Mch challenge. There were no significant decreases in EPO, EOS, and serum IgE or lung inflammation on histopathological examination. Conclusions Our results show that recombinant SLPI therapy may decrease AHR in a murine model of asthma. The results from our study indicate that serine proteinases may play a role in AHR in asthma.
Glutathione deficiency produced by inhibition of its synthesis, and its reversal; applications in research and therapy.

Glutathione, which is synthesized within cells, is a component of a pathway that uses NADPH to provide cells with their reducing milieu. This is essential for (a) maintenance of the thiols of proteins (and other compounds) and of antioxidants (e.g. ascorbate, α-tocopherol), (b) reduction of ribonucleotides to form the deoxyribonucleic precursors of DNA, and (c) protection against oxidative damage, free radical damage, and other types of toxicity. Glutathione interacts with a wide variety of drugs. Despite its many and varied cellular functions, it is possible to achieve therapeutically useful modulations of glutathione metabolism. This article emphasizes an approach in which the synthesis of glutathione is selectively inhibited in vivo leading to glutathione deficiency. This is achieved through use of transition-state inactivators of γ-glutamylcysteine synthetase, the enzyme that catalyzes the first and rate-limiting step of glutathione synthesis. The effects of marked glutathione deficiency, thus produced in the absence of applied stress, include cellular damage associated with severe mitochondrial degeneration in a number of tissues. Such glutathione deficiency is not prevented or reversed by giving glutathione. The cellular utilization of GSH involves its extracellular degradation, uptake of products, and intracellular synthesis of GSH. This is a normal pathway by which cysteine moieties are taken up by cells. Glutathione deficiency induced by inhibition of its synthesis may be prevented or reversed by administration of glutathione esters which, in contrast to glutathione, are readily transported into cells and hydrolyzed to form glutathione intracellularly. Research derived from this model has led to several potentially useful therapeutic approaches, one of which is currently in clinical trial. Thus, certain tumors, including those that exhibit resistance to several drugs and to radiation, are sensitized to these modalities by selective inhibition of glutathione synthesis. An alternative interpretation is suggested which is based on the concept that some resistant tumors have high capacity for glutathione synthesis and that such increased capacity may be as significant or more significant in promoting the resistance of some tumors than the cellular levels of glutathione. Therapeutic approaches are proposed in which normal cells may be selectively protected against toxic antitumor agents and radiation by cysteine- and glutathione-delivery compounds. Current studies suggest that research on other modulations of glutathione metabolism and transport would be of interest.
An Origami Inspired Reconfigurable Spiral Antenna

Modern day systems often require reconfigurability in the operating parameters of the transmit and receive antennas, such as the resonant frequency, radiation pattern, impedance, or polarization. In this work a novel approach to antenna reconfigurability is presented by integrating antennas with the ancient art of origami. The proposed antenna consists of an inkjet printed center-fed spiral antenna, which is designed to resonate at 1.0GHz and have a reconfigurable radiation pattern while maintaining the 1.0GHz resonance with little variation in input impedance. When flat, the antenna is a planar spiral exhibiting a bidirectional radiation pattern. By a telescoping action, the antenna can be reconfigured into a conical spiral with a directional pattern and higher gain, which gives the antenna a large front-to-back ratio. Construction of the antenna in this manner allows for a simple, lightweight, transportable antenna that can expand to specifications in the field.Copyright © 2014 by ASME
A molecular mechanism for the production of muscular work

Motility in biological systems is widely thought to result from the transduction of chemical free energy. In muscle a difficulty has been encountered in finding a precise mechanism whereby this conversion is accomplished. We suggest that this difficulty resides in the macroscopic character of free energy which, as a thermodynamic quantity, deals only with large assemblages of molecules. However, the fundamental site of active movement has recently been found to be localized in a single molecule (a myosin head) and is therefore not open to thermodynamic treatment. It is suggested instead that the energetic source of work produced at the myosin head is to be found in the heat (in the form of kinetic energy) evolved during an actomyosin ATPase cycle. This heat equivalent kinetic energy is then converted into useful work by means of a vibrational mode of a single water molecule which is attached to the ADP formed in the myosin head during a portion of the actomyosin ATPase cycle. It is the resonance mode of this water molecule which enables the extremely short durations (∼10-15s) of the chemical reactions taking place in one actomyosin ATPase cycle to result in the much longer duration (∼10-2s) of the resulting movement. This mechanism may also be fundamental to other types of motility in living systems.
Assessing Risk-taking in a Driving Simulator Study: Modeling Longitudinal Semi-continuous Driving Data Using a Two-part Regression Model with Correlated Random Effects

Signalized intersection management is a common measure of risky driving in simulator studies. In a recent randomized trial, investigators were interested in whether teenage males exposed to a risk-accepting passenger took more intersection risks in a driving simulator compared with those exposed to a risk-averse peer passenger. Analyses in this trial are complicated by the longitudinal or repeated measures that are semi-continuous with clumping at zero. Specifically, the dependent variable in a randomized trial looking at the effect of risk-accepting versus risk-averse peer passengers on teenage simulator driving is comprised of two components. The discrete component measures whether the teen driver stops for a yellow light, and the continuous component measures the time the teen driver, who does not stop, spends in the intersection during a red light. To convey both components of this measure, we apply a two-part regression with correlated random effects model (CREM), consisting of a logistic regression to model whether the driver stops for a yellow light and a linear regression to model the time spent in the intersection during a red light. These two components are related through the correlation of their random effects. Using this novel analysis, we found that those exposed to a risk-averse passenger have a higher proportion of stopping at yellow lights and a longer mean time in the intersection during a red light when they did not stop at the light compared to those exposed to a risk-accepting passenger, consistent with the study hypotheses and previous analyses. Examining the statistical properties of the CREM approach through simulations, we found that in most situations, the CREM achieves greater power than competing approaches. We also examined whether the treatment effect changes across the length of the drive and provided a sample size recommendation for detecting such phenomenon in subsequent trials. Our findings suggest that CREM provides an efficient method for analyzing the complex longitudinal data encountered in driving simulation studies.
A Telemedicine-Based Intervention Reduces the Frequency and Severity of COPD Exacerbation Symptoms: A Randomized, Controlled Trial

Abstract Background: Patients with chronic obstructive pulmonary disease (COPD) may not recognize worsening symptoms that require intensification of therapy. They may also be reluctant to contact a healthcare provider for minor worsening of symptoms. A telemedicine application for daily symptom reporting may reduce these barriers and improve patient outcomes. Materials and Methods: Patients hospitalized for a COPD exacerbation within the past year or using supplemental O2 were approached for participation. Patients received optimal COPD care and were given a telecommunication device for symptom reporting. Initial symptom scores were obtained while patients were in their usual state of health. Patients were randomly assigned to an intervention group or a control group (usual medical care). The control group patients were instructed to seek medical care if their condition worsened. The intervention group symptom scores were assessed by a computer algorithm and compared with initial values. Scores 1 or more ...
Numerical Instability at the Edge of a Dynamic Fracture

SUMMARY Numerical solutions by finite-difference techniques to problems of dynamical fracture growth exhibit oscillations with large amplitudes near the edges of the fractures that are caused by the stepwise advance of the edge of the crack across the computational lattice. In their turn, the oscillations cause anomalously large velocities of crack growth and slightly larger than expected velocities of slip in the interior of the crack. These undesirable consequences of computation of dynamical fractures on a discrete lattice can be minimized by the insertion of dissipation in the elastic properties of the system having about 1/3 of the value for critical damping at the lattice cutoff frequency. Numerical solutions of problems of dynamical fracture growth frequently exhibit large oscillations, especially near the edge of the fracture. We show that the wavelength is twice the lattice spacing. Examples can be seen in one-dimensional simulations of Carlson & Langer (1989), in two-dimensional simulations by Campillo & Ionescu (1997), in three-dimensional simulations of Fukuyama & Madariaga (1995), and others. It has been uncertain whether these oscillations are due to approximations in the numerical procedures,which are usually reduced by increasing the density of lattice sites in the numerical analysis, or whether the instability is inherent in the discretization in all finite difference schemes of integration (Fukuyama & Madariaga, 1995). We show that the oscillatory instabilities due to the discretization can be very large. These oscillations may cause significant errors in the calculation of the rate of crack growth. In this paper we show that discretization of the Laplacian operator on a finite grid in a finite-difference procedure has inherent, significant instabilities at any lattice spacing at and near the edge of a dynamically growing crack. These instabilities have three undesirable properties; the numerical solutions display oscillations with very large amplitudes, the velocity of crack growth may be seriously overestimated and the average slip velocity behind the advancing edge may also be slightly greater than expected from the solutions for the corresponding continuum crack. We derive a correction that leads to a satisfactory reduction of the sizes of all three of these errors.
Modeling and control of multi-contact centers of pressure and internal forces in humanoid robots

This paper presents a methodology for the modeling and control of internal forces and moments produced during multi-contact interactions between humanoid robots and the environment. The approach is based on the virtual linkage model which provides a physical representation of the internal forces and moments acting between the various contacts. The forces acting at the contacts are decomposed into internal and resulting forces and the latter are represented at the robot's center of mass. A grasp/contact matrix describing the complex interactions between contact forces and center of mass behavior is developed. Based on this model, a new torque-based approach for the control of internal forces is suggested and illustrated on the Asimo humanoid robot. The new controller is integrated into the framework for whole-body prioritized multitasking enabling the unified control of operational tasks, postures, and internal forces.
Agent-based modelling of software market share evolution: the factors and simulations

In the software industry, 'market share' refers to the percentage of the total available market that is being serviced by a software product. Market share analysis and prediction are important components of managing the marketing of a software business. In this paper, we study the software market share from an ecosystem point of view. We hypothesise that the evolution of the market share of a software product is dependent on two types of factors: internal and external. We build an agent-based model to represent the evolution of the software market share and compare the market share observations with the market share simulations of various operating systems, web servers and web browsers. The results show that the agent-based model effectively incorporates various factors of software products' market share and successfully simulates their evolution.
Technology development: focus on manufacturability

The authors discuss the integration of manufacturability from the early stages of technology development based on the experiences of the leading-edge semiconductor development program at IBM's facility in Essex Junction, Vermont. An overview is presented of the methods used, the resultant line and information architectures developed, and experience and results to date. Major changes in the technology development cycle are required. The traditional laboratory role of design and process development has expanded to include a parallel responsibility for manufacturability. Design for manufacturability (DFM) and early manufacturing involvement (EMI) concepts are now major components of the development effort designed to maintain and enhance the rate of technology advancement and significantly improve the development-to-manufacturing transition. >
An accurate multirate sampling technique and its application to time-scale analysis

An accurate multirate sampling technique is presented, which constructs a sequence x(ns/spl Delta/t) from a sampled signal x(n/spl Delta/t) for any positive s, where x(n/spl Delta/t) is assumed to be sampled with the sampling theorem being satisfied. It is proven that both x(n/spl Delta/t) and x(ns/spl Delta/t) can be characterized by a sequence {c/sub m/} which can be calculated from the DFT of x(n/spl Delta/t). The theory behind the accurate sampling rate conversion is then used to develop a parallel and recursive structure for time-scale analysis. It is indicated that the new approach not only accurately realizes the time-scale analysis, but also possesses a parallel and recursive structure appropriate for efficient hardware implementation. >
The intersection between self-concepts and values: Links between beliefs and choices in high school

This chapter addresses how critical choices in the math and science pipeline can be traced back to adolescents' self-concepts of abilities and values at the beginning of high school.
Antiangiogenic and Antitumor Activity of a Selective PDGFR Tyrosine Kinase Inhibitor, CP-673,451

CP-673,451 is a potent inhibitor of platelet-derived growth factor beta-receptor (PDGFR-beta) kinase- and PDGF-BB-stimulated autophosphorylation of PDGFR-beta in cells (IC(50) = 1 nmol/L) being more than 450-fold selective for PDGFR-beta versus other angiogenic receptors (e.g., vascular endothelial growth factor receptor 2, TIE-2, and fibroblast growth factor receptor 2). Multiple models have been used to evaluate in vivo activity of CP-673,451 and to understand the pharmacology of PDGFR-beta inhibition and the effect on tumor growth. These models include an ex vivo measure of PDGFR-beta phosphorylation in glioblastoma tumors, a sponge model to measure inhibition of angiogenesis, and multiple models of tumor growth inhibition. Inhibition of PDGFR-beta phosphorylation in tumors correlates with plasma and tumor levels of CP-673,451. A dose of 33 mg/kg was adequate to provide >50% inhibition of receptor for 4 hours corresponding to an EC(50) of 120 ng/mL in plasma at C(max). In a sponge angiogenesis model, CP-673,451 inhibited 70% of PDGF-BB-stimulated angiogenesis at a dose of 3 mg/kg (q.d. x 5, p.o., corresponding to 5.5 ng/mL at C(max)). The compound did not inhibit vascular endothelial growth factor- or basic fibroblast growth factor-induced angiogenesis at concentrations which inhibited tumor growth. The antitumor efficacy of CP-673,451 was evaluated in a number of human tumor xenografts grown s.c. in athymic mice, including H460 human lung carcinoma, Colo205 and LS174T human colon carcinomas, and U87MG human glioblastoma multiforme. Once-daily p.o. x 10 days dosing routinely inhibited tumor growth (ED(50) < or = 33 mg/kg). These data show that CP-673,451 is a pharmacologically selective PDGFR inhibitor, inhibits tumor PDGFR-beta phosphorylation, selectively inhibits PDGF-BB-stimulated angiogenesis in vivo, and causes significant tumor growth inhibition in multiple human xenograft models.
Single-Nucleotide Polymorphisms for High-Throughput Genotyping of Anopheles arabiensis in East and Southern Africa

ABSTRACT Anopheles arabiensis Patton is one of the principal vectors of malaria in sub-Saharan Africa, occupying a wide variety of ecological zones. This species is increasingly responsible for malaria transmission in Africa and is becoming the dominant vector species in some localities. Despite its growing importance, little is known about genetic polymorphisms in this species. Multiple sequences of various gene fragments from An. arabiensis isolates from Cameroon were obtained from GenBank. In total, 20 gene fragments containing single-nucleotide polymorphisms (SNPs) at moderate density were selected for direct sequencing from field collected specimens from Tanzania and Zambia. We obtained 301 SNPs in total from the 20 gene fragments, 60 of which were suitable for Illumina GoldenGate SNP genotyping. A greater number of SNPs (n = 185) was suitable for analysis using Sequenom iPLEX, an alternative high-throughput genotyping technology using mass spectrometry. An SNP was present every 59 (± 44.5) bases on ...
Effect of initiators, lewis acids, deactivators, additives and medium on controlled/“living” carbocationic systems

Effect of nucleofugacity of leaving group, X, nucleophilicity/basicity of the formed counteranion, X− or MtXn+1−, and groups stabilizing positive charge in the carbocation, R+, generated from initiator, RX, as well as metal and ligands in the Lewis acids, MtXn, strength of protonic acids, HA, added salts, NR4+X−, nucleophiles, Nu, some other additives and also reaction conditions on controlled/“living” carbocationic polymerization is discussed. The role of all of the components is explained and their rational design for various monomers which can be polymerized cationically to well defined polymers and copolymers is provided.
Multisensor Dynamic Waveform Fusion

Speech communication is significantly more difficult in severe acoustic background noise environments, especially when low-rate speech coders are used. Non-acoustic sensors, such as radar sensors, vibrometers, and bone-conduction microphones, offer significant potential in these situations. We extend previous work on fixed waveform fusion from multiple sensors to an optimal dynamic waveform fusion algorithm that minimizes both additive noise and signal distortion in the estimated speech signal. We show that a minimum mean squared error (MMSE) waveform matching criterion results in a generalized multichannel Wiener filter, and that this filter will simultaneously perform waveform fusion, noise suppression, and crosschannel noise cancellation. Formal intelligibility and quality testing demonstrate significant improvement from this approach.
Enacted Support during Stressful Life Events in Middle and Older Adulthood: An Examination of the Interpersonal Context

Individuals often turn to their close social ties for support during stressful life events. Although a great deal of work examines perceived support (i.e., support believed to be available should an event occur), less is known about enacted support (i.e., support actually provided during stressful events), especially among middle-aged and older people. The present study investigated whether enacted support (emotional or instrumental) varies by relationship quality and stress appraisals. Participants included 152 adults (principal respondents; aged 50 to 69 years, 63% women) who had experienced three or more stressful life events in the last year and 180 of their identified supportive ties (core network members). Multilevel models revealed that higher quality relationships enact high levels of support irrespective of high or low stress appraisals. In contrast, lower quality relationships enact greater support under conditions of higher stress but less support under conditions of lower stress, suggesting that lower quality relationships are mobilized only under higher levels of stress. Findings are consistent with the support provision process model and highlight the importance of considering relationship context and the stress continuum in studies of enacted support among older adults.
Two-color, cytokeratin-labeled dna flow cytometric analysis of 332 breast cancers: lack of prognostic value with 12-year follow-up.

Abstract Context.—DNA flow cytometry of breast cancer is a proposed tumor marker of prognostic significance that is of controversial clinical utility because of lack of standardization and confirmatory studies. Objective.—To evaluate the prognostic significance of the more informative technique of multiparametric 2-color DNA flow cytometry as recommended by the 1992 DNA Cytometry Consensus Conference. Design.—Three hundred thirty-two breast carcinomas with 7 to 12 years of follow-up were prospectively analyzed as fresh tumors that were mechanically dissociated into whole cell suspensions. These suspensions were dual fluorescence–labeled with propidium iodide (DNA) and antibodies to cytokeratin (epithelium) and leukocyte common antigen (internal leukocyte control) for gated analysis of subpopulations. Multicycle software with histogram-dependent algorithms employing background, aggregate, and debris correction were used in DNA and cell-cycle quantitation. Data were analyzed according to the DNA Flow Cytome...
Analysis of the Sensory Profile in Children with Smith–Magenis Syndrome

This study systematically assessed sensory processing in 34 children, aged 3-14 years, with Smith-Magenis syndrome (SMS) using the Sensory Profile Caregiver Questionnaire. Scores for the SMS cohort were significantly different from scores of the national sample of children with and without disabilities in all Sensory Profile categories and quadrants (p < .001). No main effects of age or gender were found, but an interaction effect of age by gender was found in Modulation of Sensory Input Affecting Emotional Responses, in which older females presented with the lowest scores. A significant decline over time was found in the Seeking pattern, reflecting increased vulnerability (p < .05). Nonsignificant trends suggest more vulnerabilities for older versus younger children, especially older females. The neurobehavioral phenotype in children with SMS is expanded by this description of sensory processing. How children with SMS experience and respond to everyday sensations informs multidisciplinary team decisions.
Refining our criteria: a critical challenge.

An article in the December 2008 issue of the Journal 1 raises a variety of issues that are key to the implementation of the universal definition of myocardial infarction (AMI).2–4 The group from Catalonia, Spain, evaluated a strategy using a contemporary, not an ultrasensitive, cardiac troponin (cTn) assay from Siemens Healthcare Diagnostics (Tarrytown, NY) in 284 consecutive patients. They applied criteria for AMI using the old iteration of the Bayer assay (Bayer, Tarrytown, NY) and a set of criteria using values above the 99th percentile with the newer, more sensitive TnI-Ultra assay in association with a 20% change. They reported an ability to diagnose 66 additional episodes of acute myocardial injury with this approach. This is slightly more than half of the 109 times that they observed values above the 99th percentile. They suggest that this approach increased their specificity for diagnosing acute cardiac injury. Furthermore, they thought clinically that more than half of the patients who might have been diagnosed as meeting criteria for acute cardiac injury had some other serious medical complications such as heart failure and nonanginal chest pain to explain the elevations rather than AMI. Irrespective, apparently, of the diagnosis, these patients were at increased risk during follow-up. How these diagnoses were quality assured is unclear, and a receiver operating characteristic curve analysis would also have helped to more clearly characterize the phenomena reported. One of the benefits of this sort of an analysis is that it helps to refine how we use cTn assays. It amplifies certain critical issues that are important and leaves open several issues that are worthy of discussion. The first issue has to do with the designation of the assay used as an “ultrasensitive” cTn assay. The Siemens cTnI-Ultra assay is, in our view, a contemporary assay with …
A general approach for the stability analysis of the time-domain finite-element method for electromagnetic simulations

This paper presents a general approach for the stability analysis of the time-domain finite-element method (TDFEM) for electromagnetic simulations. Derived from the discrete system analysis, the approach determines the stability by analyzing the root-locus map of a characteristic equation and evaluating the spectral radius of the finite element system matrix. The approach is applicable to the TDFEM simulation involving dispersive media and to various temporal discretization schemes such as the central difference, forward difference, backward difference, and Newmark methods. It is shown that the stability of the TDFEM is determined by the material property and by the temporal and spatial discretization schemes. The proposed approach is applied to a variety of TDFEM schemes, which include: (1) time-domain finite-element modeling of dispersive media; (2) time-domain finite element-boundary integral method; (3) higher order TDFEM; and (4) orthogonal TDFEM. Numerical results demonstrate the validity of the proposed approach for stability analysis.
Weight gain associated with chronic exposure to chlorpyrifos in rats.

Objective This work exposed rats to low levels of the organophosphate insecticide chlorpyrifos and monitored for toxic effects, including weight gain.
Automated instrument for measuring biological transport kinetics over intervals of a few seconds.

Automated sampling device was designed to permit determination of rates of biological transport of metabolites into cells. The substrate was automatically introduced into a stirred cell suspension at 37°C. The first sample was automatically taken after a mixing interval of 1 sec and nine subsequent samples were taken at programmable intervals (1 to 100 sec). The samples were forced by pressure differential (vacuum) through 0.4 μ pore size membranes and approximately 50 μl were collected in disposable cups. The duration of the sampling interval was controllable down to 0.1 sec. The samples preserved records of the substrate concentrations in solution at the time of filtration. With the use of suitable radioactive labeled isotopes, the changes in substrate concentrations may be conveniently measured by liquid scintillation spectrometry, but other analytical procedures of suitable sensitivity may be used. Initial and steady-state transport rates of succinate and glucose in Escherichia coli were obtained using the device.