cssi/SciSciGPT-SciSciNet huggingface dataset:
Epidemiologic Approaches for the Identification of Asthma

Clinical, physiologic, and questionnaire approaches can be used to identify subjects with asthma in an epidemiologic investigation. Each method, however, may select differing subsets of the population. At present, a comprehensive asthma questionnaire is unavailable; the difficulty of defining asthma in operational terms has been a major obstacle in the development of such a questionnaire. This review describes the questionnaires prepared by the British Medical Research Council and the American Thoracic Society and suggests modifications.
A data systems intern program

We shall deliver a two-part paper this afternoon concerning a Data Systems Intern Program in the National Security Agency of the U. S. Department of Defense. Before we begin our discussion of the program, I should like to give you some background. Although there is comparatively little that we can say about the National Security Agency, we are at liberty to inform you that NSA is responsible for the security of U. S. communications. To ensure the greatest degree of security for U. S. communications, NSA uses specially-designed computers and high-speed data processing equipment to produce and to test the U. S. Government's cryptographic systems. As NSA, therefore, the computer is an important tool and the agency needs its share of competent professionals in the field.
Phase transitions for a continuous system of classical particles in a box

A continuous classical system involving an infinite number of distinguishable particles is analyzed along the same lines as its quantum analogue, considered in [1]. A commutativeC*-algebra is set up on the phase space of the system, and a representation-dependent definition of equilibrium involving the static KMS condition is given. For a special class of interactions the set of equilibrium states is realized as a convex Borel set whose extremal states are characterized by solutions to a system of integral equations. By analyzing these integral equations, we prove the absence of phase transitions for high temperature and construct a phase transition for low temperature. The construction also provides an example of a translation-invariant state whose decomposition at infinity yields states that are not translation-invariant. Thus we have an example in the classical situation of continuous symmetry breaking.
28 Lipid composition of members of the algal class chlorarachniophyceae

The algal class Chlorarachniophyceae is comprised of a small group of unicellular eukaryotic algae that are often characterized by an unusual amoeboid morphology. This morphology is hypothesized to be the result of a secondary endosymbiosis in which a green alga was engulfed as prey by a nonphotosynthetic amoeba or amoebaflagellate. Whereas much is known about the phylogenetic relationships of individual chlorarachniophytes to one another, and to possible ancestral host organisms in the genera Cercomonas and Heteromita, little is known about their physiology, particularly that of their lipids. In an initial effort to characterize the lipids of this algal class, seven organisms were examined for their fatty acid and sterol composition. These included Bigelowiella natans, Chlorarachnion globusum, Chlorarachnion reptans, Gymnochlora stellata, Lotharella amoeboformis, Lotharella globosa, and Lotharella sp. Fatty acids associated with chloroplast-associated glycolipids, cytoplasmic membrane-associated phospholipids, and storage triglycerides were characterized. Glycolipid fatty acids were found to be of limited composition, containing principally eicosapentaenoic acid [20:5(n-3)] and hexadecanoic acid (16:0), which ranged in relative percentage from 67–90% and 10–29%, respectively, in these seven organisms. Triglyceride-associated fatty acids were found to be similar. Phospholipid fatty acid composition was more variable. The principal phospholipid fatty acids, 16:0 (25–32%) and a compound tentatively identified as docosapentaenoic acid [22:5(n-3)] (26–35%), were found along with a number of C18 and C20 fatty acids. All organisms contained two sterols as free sterols. These were tentatively identified as 24-ethylcholesta-5,22E-dien-3b-ol (stigmasterol; 70–95%) and 24-methylcholesta-5,22E-dien-3b-ol (brassicasterol; 5–30%).
The influence of patella alta on patellofemoral joint stress during normal and fast walking.

Abstract Objective: To determine if persons with patella alta exhibit elevated patellofemoral joint stress compared to pain-free controls during normal and fast walking speeds. Subjects: Twenty-four subjects (13 patella alta, 11 pain-free controls) participated. Methods: Sagittal and axial magnetic resonance images of the knee were obtained to quantify subject specific knee extensor mechanics and patellofemoral joint contact area. Instrumented gait analysis was used to quantify knee joint kinematics and kinetics. MRI and gait data were used as input variables into a model of patellofemoral joint stress. Analysis of variance with repeated measures was used to compare group differences and group×gait speed interactions for each dependent variable during stance. Results: During normal speed gait there were no group differences in peak knee flexion angle, knee extensor moment, joint reaction force, or stress. However, the patella alta group had significantly less contact area. During fast speed gait there were no group differences in peak knee flexion angle, knee extensor moment, or joint reaction force. However, the patella alta group demonstrated significantly less contact area and significantly greater stress compared to controls. Conclusion: Persons with patella alta demonstrated greater calculated patellofemoral stress during fast walking. This was the result of reductions in contact area as joint reaction forces were similar between groups. Relevance Persons with patella alta may be predisposed to patellofemoral dysfunction through elevations in joint stress. Therefore, treatments aimed at increasing the load-bearing surface area between the patella and femur, such as bracing, may be beneficial in this patient population.
Retention and stability of the maxillary denture during function

The objectives of this study were to provide a quantitative account of the extent to which the maxillary complete denture moves during function (chewing, swallowing, and speech production) and to determine whether differences in movement occur as a function of denture fit. A total of 24 patients were studied, 12 with poorly fitting dentures and 12 with well-fitting dentures. Denture movements were measured with a Myotronics kinesiograph that tracked the movements of a small magnet attached to the inferior surface of the denture. Results indicated that denture movement was greatest for the two chewing activities; varied extensively from individual to individual; and that there were no statistically significant overall movement effects as a function of fit. It was concluded that all maxillary dentures are subject to movements in all directions, but that the degree of movement is related more to the individual denture wearer than it is to the fit of the denture.
Stopping cancer before it colonizes

Controlling the growth of cancer cells at metastatic sites is one goal of cancer drug development. Studies of metastasis suppressor function bring this long-sought goal closer ( pages 933 – 938 ).
Modulation of AD neuropathology and memory impairments by the isoprostane F2α is mediated by the thromboxane receptor

Beside amyloid-β plaques and neurofibrillary tangles, brain oxidative damage has been constantly implicated in Alzheimer's disease (AD) pathogenesis. Numerous studies demonstrated that F2-isoprostanes, markers of in vivo lipid peroxidation, are elevated in AD patients and mouse models of the disease. Previously, we showed that the 8-isoprostaneF2α, (8ISO) increases brain amyloid-β levels and deposition in the Tg2576 mice. However, no data are available on its effects on behavior and tau metabolism. To this end, we characterize the behavioral, biochemical, and neuropathologic effects of 8ISO in the triple transgenic mouse model. Compared with controls, mice receiving 8ISO showed significant memory deficits, increase in tau phosphorylation, activation of the cyclin kinase 5 pathway, and neuroinflammation. All these effects were blocked by pharmacologic blockade of the thromboxane receptor. Our findings establish the novel functional role that oxidative stress via the formation of this isoprostane plays in the development of cognitive impairments and AD-related tau neuropathology. It provides important preclinical support to the neurobiological importance of the thromboxane receptor as an active player in the pathogenesis of AD.
Kinetic analysis of metal binding to the amino-terminal domain of ZntA by monitoring metal-thiolate charge-transfer complexes.

ZntA, a P1B-ATPase transporter from Escherichia coli, mediates resistance specifically to Pb2+, Zn2+, and Cd2+ by active efflux. ZntA has a hydrophilic N-terminal domain that binds one metal ion. This domain, ∼120 residues long, contains the GXXCXXC motif that has been shown to be the binding site for metal ions such as Cu+ and Zn2+ in P1B-type ATPases, and an additional cysteine-rich motif, CCCDGAC. We report here that binding of Pb2+ and Cd2+ to this domain produces changes in the absorbance spectrum in the 250−400 nm range indicative of metal−thiolate charge-transfer complexes. The spectral changes indicate that only two cysteines are ligands to Cd2+, but three or more cysteines are involved in binding Pb2+; this confirms earlier results that the GXXCXXC sequence is not sufficient to bind Pb2+, which likely involves residues from the CCCDGAC motif. The absorbance changes were used to measure metal binding kinetics of the N-terminal domain using stopped-flow techniques. Binding was described by simple s...
The human drug metabolizing cytochromes P450

The superfamily of heme-thiolate proteins known as the cytochromes P450 is responsible for the oxidative metabolism of the majority of drugs. Thus, the phenotypes of individuals with respect to their levels of catalytically active cytochromes P450 determines to a large part the substantial interindividual variation observed in the metabolic clearance of drugs. Over the past 10 years 15 different human cytochromes P450 involved in drug metabolism have been isolated and characterized to varying degrees. This brief review discusses the characterization of these cytochromes P450 and how this knowledge has been used by the pharmaceutical industry to aid in the development of new drugs.
Enzymatic oxidation of water-soluble cyclodextrin-polynuclear aromatic hydrocarbon inclusion complexes, using lignin peroxidase

Abstract α-, β-, γ-, and 2-hydroxypropyl-β-cyclodextrins were capable of forming water-soluble inclusion complexes with several polynuclear aromatic hydrocarbons (PAHs). The highest solubilities were noted for β-cyclodextrin and 2-hydroxypropyl-β-cyclodextrin (hpβCD). The solubility of PAHs in hpβCD was enhanced 224-fold and 7,500-fold for naphthalene and benzo[a]pyrene, respectively, with other PAHs yielding values between these limits. The ability of lignin peroxidase (LiP) to oxidize these cyclodextrin-included substrates was similar to that previously reported for mixed solvent systems. The enzyme oxidized anthracene, pyrene, and benzo[a]pyrene but not naphthalene, phenanthrene, chrysene, and benzo[e]pyrene. The lignin peroxidase exhibited a preference for oxidizing either anthracene or benzo[a]pyrene when mixed with pyrene. On the basis of fluorescence measurement, anthracene and benzo[a]pyrene were easily distinguished by exciting at 250 nm for anthracene and 295 nm for benzo[a]pyrene. Veratryl alcohol severely inhibited the pyrene assay, with 50% inhibition noted at 0.3 m m while veratryl alcohol activated the reactions between LiP and either anthracene or benzo[a]pyrene. Maximal activation was obtained at 1.5 m m veratryl alcohol and no inhibitory effect was detected up to 4.0 m m . Under identical conditions, the rate of reaction with veratryl alcohol (4.0 m m ) was 11- and 14-fold faster for benzo[a]pyrene and anthracene, respectively, when compared to the assays in the absence of veratryl alcohol.
Aging and the Brown Norway Rat Leydig Cell Antioxidant Defense System

Previous studies have shown that testosterone production by the Leydig cells of aged Brown Norway rats is reduced from the relatively high levels produced by Leydig cells of young rats and that this reduction is not secondary to decreased serum luteinizing hormone concentration. The free radical theory of aging proposes that imbalance between pro-oxidants and the antioxidant defense system ultimately results in oxidative damage to cellular processes. With this in mind, we hypothesized herein that age-related reductions in steroidogenesis by Brown Norway rat Leydig cells may be associated with the impairment of the antioxidant defense system of these cells. To begin to test this hypothesis, we compared the activities and steady-state mRNA and protein levels of the antioxidant enzymes copper zinc (CuZn) superoxide dismutase (CuZnSOD, SOD1), manganese (Mn) superoxide dismutase (MnSOD, SOD2), and glutathione peroxidase (GPx) and the levels of reduced and oxidized glutathione in Leydig cells isolated from the testes of young (4-month-old) and aged (20-month-old) Brown Norway rats. For some studies, Leydig cells were isolated separately from aged testes that either had regressed because of age-related losses of germ cells or that were nonregressed. SOD (total) and GPx activities were found to decrease significantly with age whether or not the testes were regressed. CuZnSOD and MnSOD mRNA levels decreased with aging, though the magnitude of the decreases were considerably lower than the respective decreases in enzyme activities. GPx mRNA levels also decreased, which is consistent with the decreases seen in enzyme activity. MnSOD protein expression declined with age, and to a lesser extent, CuZnSOD did as well. Reduced and oxidized glutathione also exhibited age-related reductions in cells from both normal and regressed aged testes. The age-related decreases in Leydig cell antioxidant enzyme activities, gene expression, and protein levels and in glutathione were consistent with the hypothesis that the loss of steroidogenic function that accompanies Leydig cell aging may result in part from a decrease in the fidelity of the cellular antioxidant defense system.
Human iPS cell-derived hematopoietic progenitor cells induce T-cell anergy in in vitro generated alloreactive CD8+ T-cells

Human induced pluripotent stem cells (iPSCs) have emerged as an alternative source of pluripotent stem cells that can be used for tissue regeneration in place of the controversial human embryonic stem cells. However, immunologic knowledge about iPSC derivatives remains enigmatic. Here, we characterized human iPS-derived CD34(+) hematopoietic progenitor cells (HPCs). These HPCs poorly express major histocompatibility complex (MHC) I antigens and are MHC-II negative. Interestingly, they moderately express nonclassical HLA-G and HLA-E molecules. Consequently, alloreactive HLA-A2-specific cytotoxic T cells failed to recognize HLA-A2-expressing HPCs but became anergic. Subsequent upregulation of MHC-I using interferon-γ stimulation and provision of CD28 cosignaling led to T-cell activation, confirming that poor delivery of signals 1 and 2 by the HPCs mediated T-cell anergy. These data indicate for the first time that HPCs induce T-cell anergy, a unique characteristic of iPSC-derived cells that confers immunologic advantage for allogenic transplantation. Although iPSCs are ideal for patient-tailored treatments with the anticipation that no immunosuppression will be required, in cases of gene defects, their derivatives could be used to treat diseases in nonhistocompatible recipients.
Exposure to Δ9-Tetrahydrocannabinol Impairs the Differentiation of Human Monocyte-derived Dendritic Cells and their Capacity for T cell Activation

The capacity for human monocytes to differentiate into antigen-presenting dendritic cells (DC) can be influenced by a number of immune modulating signals. Monocytes express intracellular cannabinoid type 1 (CB1) and 2 (CB2) receptors and we demonstrate that exposure to Δ9-tetrahydrocannabinol (THC) inhibits the forskolin-induced generation of cyclic adenosine monophosphate in a CB2-specific manner. In order to examine the potential impact of cannabinoids on the generation of monocyte-derived DC, monocytes were cultured in vitro with differentiation medium alone [containing granulocyte/macrophage-colony stimulating factor (GM-CSF) and Interleukin-4 (IL-4)] or in combination with THC. The presence of THC (0.25–1.0 μg/ml) altered key features of DC differentiation, producing a concentration-dependent decrease in surface expression of CD11c, HLA-DR and costimulatory molecules (CD40 and CD86), less effective antigen uptake, and signs of functional skewing with decreased production of IL-12 but normal levels of IL-10. When examined in a mixed leukocyte reaction, DC that had been generated in the presence of THC were poor T cell activators as evidenced by their inability to generate effector/memory T cells or to stimulate robust IFN-γ responses. Some of these effects were partially restored by exposure to exogenous IL-7 and bacterial superantigen (S. aureus Cowans strain). These studies demonstrate that human monocytes express functional cannabinoid receptors and suggest that exposure to THC can alter their differentiation into functional antigen presenting cells; an effect that may be counter-balanced by the presence of other immunoregulatory factors. The impact of cannabinoids on adaptive immune responses in individuals with frequent drug exposure remains to be determined.
System Identification for a Miniature Helicopter at Hover Using Fuzzy Models

The objective of this paper is to present a system identification method suitable for miniature rotorcrafts under hovering. The proposed model to be identified is a Takagi-Sugeno fuzzy system, representing translational and rotational velocity dynamics. For parameter estimation of the Takagi-Sugeno system a classical Recursive Least Squares (RLS) algorithm is used, which allows identification to take place on-line since parameter updates are produced whenever a new measurement becomes available. The validity of this approach is tested using the X-Plane © flight simulator. Data obtained offer justification for the applicability of the approach in real-time applications.
Type D personality : the heart, stress, and cortisol

Many studies have demonstrated the role of psychosocial and behavioural risk factors in the aetiology and pathogenesis of cardiovascular disorders. Recently, a new personality construct, the type D or 'distressed' personality, has been proposed. Type D behaviour is characterized by the joint tendency to experience negative emotions and to inhibit these emotions while avoiding social contacts with others. The observation that cardiac patients with type D personality are at increased risk for cardiovascular morbidity and mortality underlines the importance of examining both acute (e.g. major depression) and chronic (e.g. certain personality features) factors in patients at risk for coronary events. Both type D dimensions (negative affectivity and social inhibition) are associated with greater cortisol reactivity to stress. Elevated cortisol may be a mediating factor in the association between type D personality and the increased risk for coronary heart disease and, possibly, other medical disorders. Studies of the effect of age on hypothalamic-pituitary-adrenal (HPA) function in healthy humans have produced inconsistent results. This may relate to a different prevalence of type D individuals in study samples (i.e. some type D individuals may have alterations within the HPA axis that are similar to HPA axis changes in depressed patients). Further studies of the psychological and biological features of type D individuals may help develop treatment approaches to improve the psychological and physical health of individuals with type D personality.
Chlorophenol Reactions on Fly Ash. 1. Adsorption/Desorption Equilibria and Conversion to Polychlorinated Dibenzo-p-dioxins

Tetrachlorophenol (T 4 CP) reactions to PCDD products in the presence of MSWI fly ash were measured as a function of gas-phase precursor concentration, reaction time, and reaction temperature. Tetrachlorophenol concentrations ranged from 150 to 700 ng/mL in 10% O 2 , and temperatures ranged from 250 to 400 °C, which resulted in PCDD formation rates from about 0 to 35 μg of PCDD (g-fly ash) -1 min -1 . Reaction conditions were found such that the reactor approached differential behavior, which led to the breakthrough of the T4CP and the desorption of adsorbed PCDD products into the gas-phase. At constant temperature, the surface coverage of chlorophenols on fly ash was found to be constant for reaction times between 2 and 120 min, suggesting that the system had quickly reached adsorption/desorption equilibrium. Yields of PCDD were observed to increase with increasing precursor concentration but either peaked, leveled off, or increased as the temperature was raised. Studies of T4CP reactions on different fly ashes showed a correlation between total conversion of T 4 CP-to unknown products-and total yield of the trace reaction forming PCDD.
Analysis of Deformation Kinetics in Seven Body-Centered-Cubic Pure Metals Using a Two-Obstacle Model

Published temperature and strain-rate-dependent yield stress data in seven nominally pure bcc metals are analyzed according to a two-obstacle model. A strong intrinsic lattice resistance such as a Peierls barrier and a weaker obstacle representing the collective effects of impurity constituents are combined in a single expression and fit to the individual data sets. Sensitivity of the model fits to selected model parameters is assessed. The activation volume for each obstacle is evaluated and examined to validate the underlying model assumptions. Application of the model demonstrates a consistent Peierls barrier in all seven metals and a reasonable carbon-content dependence in iron of the strength of the impurity obstacle.
Linear programs in topological vector spaces

Versions of linear programming in abstract spaces have been formulated by Duffin [5], Hurewicz [8], Kretschmer [IO], Fan [6], and Ben-Israel, Charnes, and Kortanek (BCK) [2, 31. In this paper, yet another, rather geometric, formulation of linear programming is presented in which the duality theorem of classical linear programming holds almost verbatim (Theorem 1). A sufficient condition for the existence of optimal solutions is also given (Theorem 2). The duality and existence theorems of Duffin’s formulation of linear programming [5] are shown to follow from these two theorems. The formulation of linear programming presented here may be viewed as a special case of that of BCK [2]; in fact, Kortanek and Soyster have shown [7] that the classification scheme of [2] gives a refinement of Theorem 1 of this paper. Going the other way, Theorem 1 of this paper provides a short proof of the Ben-Isreal and Charnes solvability theorem [l] which is an essential tool in proving the classification theorem of [2]. Finally, the formulation of linear programming presented here has been used in proving a duality and existence theorem in continuous linear programming [ 1 I].
E‐readers in an academic library setting

Purpose – The purpose of this paper is to show how e‐book readers are used in an academic library setting.Design/methodology/approach – The approach takes the form of a literature review and e‐mail survey to academic library administrators.Findings – Although the survey sample responding was not large, it was felt that it represented a microcosm of intelligent academic library administrators that might be involved in the eventual decision‐making process to acquire these devices for their libraries.Research limitations/implications – It would have been better if the sampling were larger. It would also have been beneficial to get a sample involving students and faculty.Practical implications – This is an interesting technology that has great potential for the future of book publishing and has great academic library possibilities.Social implications – This is a possible paradigm shifting event.Originality/value – This paper shows only the tip of the iceberg. There are much more data shortly yet to come about...
Radon transforms, laplacaians, and flows for directed graphs

We prove that Radon transforms associated to directed graphs determine a representation of the ring of isomorphism classes of directed graphs sharing a fixed set X of vertices in the complex vector space . We also express Laplacians in terms of Radon transforms, determine the Laplacians associated to the sum and product of directed graphs, and describe a relation between Laplacians and flows in directed graphs.
Sensor and actuator considerations for precision, small machines

Abstract This article reviews some design considerations for the scaling down in size of instruments and machines with a primary aim to identify technologies that may provide more optimal performance solutions than those, often established, technologies used at macroscopic, or conventional, scales. Dimensional metrology within emerging applications will be considered for meso- through micro-down to nanometer level systems with particular emphasis on systems for which precision is directly related to function. In this paper, attention is limited to some of the more fundamental issues associated with scaling. For example, actuator work or power densities or the effect of noise on the sensor signals can be readily evaluated and provide some guidance in the selection for any given size of device. However, with reductions in scale these parameters and/or phenomena that limit performance may change. Within this review, the authors have tried to assess these complex inter-relationships between performance and scale, again from a fundamental perspective. In practice, it is likely that the nuances of implementation and integration of sensor, actuator and/or mechanism designs will determine functionality and commercial viability of any particular system development.
Primary mineral weathering in the central Appalachians: a mass balance approach

Abstract We use a mass balance approach to calculate long-term weathering rates for three forested watersheds in the southeastern USA. One watershed (Shaver Hollow) is underlain by Precambrian granodiorite, and two (White Oak Run, Deep Run) are underlain by Cambrian metasedimentary units. Each of the study areas receives high levels of acidic precipitation, and each watershed was almost completely defoliated by gypsy moth larvae for at least two consecutive years during the study period. Our analysis uses stream and precipitation chemistry obtained weekly from 1987 to 1993 for Shaver Hollow and from 1980 to 1993 for White Oak Run and Deep Run. Mass balance calculations for the granodiorite watershed indicate that plagioclase feldspar is the dominant reactant and that basalt dikes which comprise a small fraction of the catchment make a significant contribution to the base cation budget. Corresponding calculations for the metasedimentary bedrock watersheds indicate contributions from plagioclase feldspar, muscovite, and biotite. At best, the mass balance models provide an approximation of weathering processes because the soils are immature and contain few stoichiometric clay minerals such as kaolinite. Annual cation release rates from Shaver Hollow suggest soil profile ages of ∼4 ka, consistent with the observed surficial geology and the geological history of the area. Base cation efflux patterns during the period of severe defoliation differ markedly between the three watersheds and reflect a continuum of ecosystem sensitivities. The Pedlar granodiorite system is relatively robust to the effects of disturbance: calculated weathering rates and proportions change by
Evidence for Decreased Secretion of Gonadotropin-Releasing Hormone in Pubertal Boys during Short-Term Testosterone Treatment

Information about the site(s) of action as well as the age-dependent effects of sex steroids on gonadotropin-releasing hormone and gonadotropin secretion during human puberty is limited. To begin to address these questions, we evaluated the effects of a depot preparation of testosterone (testosterone enanthate) on gonadotropin secretion and pituitary responses to synthetic GnRH in 10, early to mid-pubertal boys who had either isolated GH deficiency (n-2) or delayed adolescent maturation (n-8). Chronological and bone age ranges were 13 1/12-16 1/12 and 11-14 yr, respectively. Frequent blood withdrawal studies (every 20 min for 20 consecutive h) were performed in the Clinical Research Center over two consecutive weekends. Following each study, gonadotropin responses to GnRH (0.25 microgram/kg iv bolus) were determined. During the initial study, all boys showed a sleep-entrained increase in luteinizing hormone (LH) and testosterone (T) secretion; mean nocturnal concentrations of LH and T were 2.3-fold greater than daytime values. At the end of the first study, testosterone enanthate was given im (0, 25, 50, or 75 mg/m2). Six days later, mean plasma T concentrations were in the pubertal to mid adult male range and were constant throughout the day: 25 mg/m2, 3.7 +/- 0.4 (SE) ng/ml; 50 mg/m2, 4.6 +/- 0.2 ng/ml; and 75 mg/m2, 6.7 +/- 0.4 ng/ml. T treatment had no effect on pituitary responses to GnRH: mean LH increment was 8.5 mIU/ml before and 10.0 mIU/ml after T treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
The impact of playground design on the play behaviors of children with differing levels of physical competence

The impact of the outdoor learning environment on the play behaviors and peer relationships of 8 second-grade children with differing levels of physical competence was investigated using a qualitative case study approach. Subject selection was based on performance on the Bruininks-Oseretsky Test of Motor Proficiency. Settings for the study were playgrounds of contrasting design: one emphasizing exercise play, the other providing various play options in addition to exercise. Grounded theory procedures were used to analyze observation and interview data. Results indicated that playground design influenced subjects' social as well as physical skill development by facilitating or constraining the strategies they used to manage their play with peers. A theoretical model was developed to describe interrelationships among playground design, physical competence and peer relationships. Features of each playground are discussed relative to the opportunities they provided for the physical and social development of subjects with high or with low physical competence.
User-friendly, ultra-fast simulation of detector DQE(f)

Development of the indirect scintillating detector is hindered not only by the cost and lead-time of manufacturing but also the computational resources required for numerical modeling. The simulation is bogged down by the number of x-ray photons (gammas) required to duplicate the experimental flood image ensemble necessary to characterize the noise power spectrum (NPS), a key input into the detective quantum efficiency (DQE). The simulation approach presented in this work exploits our previously reported procedure named Fujita-Lubberts- Swank (FLS)6 . This novel technique computes the Lubberts NPS from an ensemble of single gamma point spread functions (PSF) and, as a result, allows for a significant reduction in the number of simulated particles, enabling full DQE(f) simulations with optical transport in less than one CPU-hour. For a given detector and spectrum, the FLS execution time is determined primarily by the number of gamma and optical photons initiated. The optimal number of each varies with the detector specifics. In this work, we present a different simulation paradigm in which Geant4 was customized to allow for the user to specify the quantities of detected gammas, and detected opticals per gamma. These quantities were empirically shown to be constant over a small selection of different detector types. While work still needs to be done to explore the range of detectors for which this technique will work, we demonstrate a concept which brings added convenience and efficiency to FLS detector simulations.
Strategies for Addressing the Executive Function Impairments of Students Prenatally Exposed to Alcohol and Other Drugs.

Students who have been exposed prenatally to alcohol or other drugs are susceptible to a range of developmental problems— from mild to severe. In this article, the authors review critical learning and behavioral problems of children exposed prenatally to alcohol and other drugs, with a specific focus on executive function deficits. They discuss various risk factors associated with prenatal drug exposure so that educators may better understand the nature of the problem and choose more effective classroom interventions that address the executive function deficits of these students. Many of the suggested interventions are also appropriate for developing executive functioning in students with attention-deficit disorders, traumatic brain injury, autism, and other disorders associated with deficits in executive functions.
The Developmental Cycle of the Andros Household: A Diachronic Analysis1

This study focuses on the changes in house-hold composition that have occurred during the past decade in four villages located on southern Andros, Bahamas. A diachronic analysis of the changes that have occurred in the Andros household is presented, using as its methodology a statistical comparison of two censuses taken seven years apart. The statistical data fail to confirm the “typical” Andros developmental cycle, which had been derived from adult life histories (the historical method) and from frequency distributions of household types at one point in time (the cross-sectional method). The existence of many different possible household cycles probably explains this failure.
Anomalous fading of thermoluminescence in meteorites

Abstract Anomalous fading in meteorites of diverse origin and history has been studied. The meteorites included the four known members of the shergottite class, Shergotty, Allan Hills A77005, Zagami and Elephant Moraine A79001, the type 3 ordinary chondrite Dhajala and the howardite Kapoeta. After irradiation and 15 days storage at room temperature, considerable fading of the TL of the Kapoeta meteorite and two of the shergottites (Shergotty and 77005) was observed, while the TL of the other shergottites and Dhajala remained constant. Mineral separation experiments and energy-dispersive X-ray analyses indicate that the phosphor responsible for the TL is located in the low-density feldspar rich fraction in the Dhajala meteorite and the shergottites and this is probably also true of Kapoeta. Despite the diverse history of the samples and major differences in composition, it is only the samples in which feldspar is thought to be present in the low-temperature form which display anomalous fading. It is argued that the present data are most consistent with the mechanism for anomalous fading involving overlap between the wavefunctions for the excited and ground state electrons. Fortunately, most meteorites contain feldspar in the high-temperature form and large scale studies of their natural TL should not be hampered by anomalous fading.
Direct evidence for the origin of low-18O silicic magmas: quenched samples of a magma chamber's partially-fused granitoid walls, Crater Lake, Oregon

Abstract Partially fused granitoid blocks were ejected in the climactic eruption of Mount Mazama, which was accompanied by collapse of Crater Lake caldera. Quartz, plagioclase, and glass in the granitoids have much lower δ 18 O values (−3.4 to +4.9‰) than any fresh lavas of Mount Mazama and the surrounding region (+5.8 to +7.0‰). Oxygen isotope fractionation between phases in granitoids is consistent with equilibrium at T ⩾ 900°C following subsolidus exchange with hydrothermal fluids of meteoric origin. Assimilation of ∼ 10–20% of material similar to these granitoids can account for the O and Sr isotopic compositions of lavas and juvenile pyroclasts derived from the climactic magma chamber, many of which have δ 18 O values ∼ 0.5‰ or more lower than comparable lavas of Mount Mazama. The O isotope data provide the only clear evidence for such assimilation because the mineralogy and chemical and radiogenic isotopic compositions of the granitoids (dominantly granodiorite) are similar to those of erupted juvenile magmas. The granitoid blocks from Crater Lake serve as direct evidence for the origin of 18 O depletion in large, shallow silicic magma bodies.
The role of unstirred layers for water exchange across the blood-brain barrier.

Abstract Theoretical considerations of the influence of unstirred layers around cerebral capillaries and of the effect of cerebral capillary endothelial cells on filtration and diffusion of water across the blood-brain barrier are presented. The theoretical analyses are applied to a previously published clinical investigation in which the filtration and diffusion permeability coefficient ( P f and P d ) were measured. In that study the P f P d ratio was found to be slightly above unity, have a value of 4.3. The analyses in the present study demonstrate that the unstirred layer, in the classic sense, in the extracellular fluid around the capillaries will not have any significant influence on either the measured P f or the P d value. The unstirred layer inside the cerebral endothelial cells will also be without significance on the measured P d values. However, for reasonable values of the parameters of the system, this unstirred layer may have a significant influence on the measured P f value and may cause it to appear to be larger than the true steady-state value. This is especially true for the case where the luminal endothelial cell membrane is more permeable to water than the abluminal. Thus, the fact that the measured P f might be too high can explain the observation of the P f P d ratio of 4.3 although a minimal amount of water might still be filtered through pores in the blood-brain barrier. Quantitatively these amounts are, however, negligible compared to the filtration in other organs.
Advanced Pancreatic Cancer: A Phase I–II Trial of Cisplatin, High-Dose Cytarabine, and Caffeine

In a phase I-II study, 28 patients with advanced pancreatic adenocarcinoma were treated with cisplatin, high-dose cytarabine (ARA-C), and caffeine. This clinical trial was based on a nude mouse-human tumor xenograft model, which demonstrated synergism of these agents by inhibiting the growth of human pancreatic tumors. Toxic effects noted in the clinical study included myelosuppression, moderate nausea and vomiting, and mild renal insufficiency. No toxic effects were directly attributable to caffeine. Eighteen of the 28 patients had measurable or assessable disease; seven (39%) had partial responses (95% confidence intervals, 18%-63%). The median response duration was 6.2 months. Median survival for responders was 9.5 months with two patients surviving for more than 18 months. Median survival for all patients was 6.1 months. The combination of cisplatin, ARA-C, and caffeine is an active and tolerable regimen in the treatment of advanced pancreatic cancer. A phase III trial in which this regimen is being compared with standard therapy is in progress.
Mini review: Mode of action of mosquito repellents

The mode of action of mosquito repellents remains a controversial topic. However, electrophysiological studies and molecular approaches have provided a better understanding of how repellents exert their effects. Here, we briefly discuss various theories of repellent action and present the current status of knowledge of the effects of repellents on olfactory and gustatory processes. These findings provide a framework for further development of existing repellents and the discovery of new compounds with novel modes of action.
Ordinal latent variable models and their application in the study of newly licensed teenage drivers

In a unique longitudinal study of teen driving, risky driving behavior and the occurrence of crashes or near crashes are measured prospectively over the first 18 months of licensure. Of scientific interest is relating the two processes and developing a predictor of crashes from previous risky driving behavior. In this work, we propose two latent class models for relating risky driving behavior to the occurrence of a crash or near crash event. The first approach models the binary longitudinal crash/near crash outcome using a binary latent variable which depends on risky driving covariates and previous outcomes. A random effects model introduces heterogeneity among subjects in modeling the mean value of the latent state. The second approach extends the first model to the ordinal case where the latent state is composed of K ordinal classes. Additionally, we discuss an alternate hidden Markov model formulation. Estimation is performed using the expectation-maximization (EM) algorithm and Monte Carlo EM. We illustrate the importance of using these latent class modeling approaches through the analysis of the teen driving behavior. Language: en
The neural crest epithelial-mesenchymal transition in 4D: a `tail' of multiple non-obligatory cellular mechanisms

An epithelial-mesenchymal transition (EMT) is the process whereby epithelial cells become mesenchymal cells, and is typified by the generation of neural crest cells from the neuroepithelium of the dorsal neural tube. To investigate the neural crest EMT, we performed live cell confocal time-lapse imaging to determine the sequence of cellular events and the role of cell division in the EMT. It was observed that in most EMTs, the apical cell tail is retracted cleanly from the lumen of the neuroepithelium, followed by movement of the cell body out of the neural tube. However, exceptions to this sequence include the rupture of the neural crest cell tail during retraction (junctional complexes not completely downregulated), or translocation of the cell body away from the apical surface while morphologically rounded up in M phase (no cell tail retraction event). We also noted that cell tail retraction can occur either before or after the redistribution of apical-basolateral epithelial polarity markers. Surprisingly, we discovered that when an EMT was preceded by a mitotic event, the plane of cytokinesis does not predict neural crest cell fate. Moreover, when daughter cells are separated from the adherens junctions by a parallel mitotic cleavage furrow, most re-establish contact with the apical surface. The diversity of cellular mechanisms by which neural crest cells can separate from the neural tube suggests that the EMT program is a complex network of non-linear mechanisms that can occur in multiple orders and combinations to allow neural crest cells to escape from the neuroepithelium.
Trellis codes for transition jitter noise

We present a trellis code which reduces the probability that transition jitter will cause one allowed sequence to be decoded as another allowed sequence. This code requires that transition times mod 4 be in the code of a 4-state convolutional encoder. We also exclude adjacent transitions (d=1). Sequences satisfying this constraint have capacity of approx. 4/9. This code can be implemented using a finite state encoder, Viterbi detector and sliding-block decoder. In the presence of pure jitter noise this code realizes a gain of approximately 3 dB over uncoded recording at the same user density.
Superoxide Anions and Endothelial Cell Proliferation in Normoglycemia and Hyperglycemia

-Oxygen free radicals are believed to play a key role in cellular proliferation, and increased concentrations of these molecules have been implicated in the pathogenesis of endothelial dysfunction in diabetes mellitus. Our aim was to study the role of superoxide anions in endothelial cell proliferation under conditions of normoglycemia and hyperglycemia. Human aortic endothelial cells (HAECs) and human umbilical vein endothelial cells (HUVECs) exposed to adenoviral vectors encoding CuZnSOD (AdCuZnSOD), ss-galactosidase (Adssgal), or diluent (control) were cultured in normal glucose (NG, 5.5 mmol/L) or high glucose (HG, 28 mmol/L) medium. Cell proliferation was compared by use of [(3)H]thymidine incorporation and cell count in transduced and control cells in the setting of NG and HG. Transgene expression was detected in transduced cells by X-gal staining and by Western analysis and SOD activity assay in AdCuZnSOD-transduced cells. Superoxide production was significantly (P:<0.05) decreased in AdCuZnSOD-transduced cells cultured in both NG and HG medium. In NG, AdCuZnSOD-transduced endothelial cells had decreased proliferation compared with control cells. After 48 hours in HG, superoxide levels were increased and DNA synthesis was decreased (P:<0.05) in control and Adssgal-transduced but were not affected in AdCuZnSOD-transduced cells. In addition, after 7 days in HG, cell counts were reduced (P:<0.05) in control (73+/-2.5%) and Adssgal-transduced (75+/-3.4%) but not in AdCuZnSOD-transduced cells (89+/-3.4%). These results suggest that either a deficiency or an excess of superoxide anions inhibits endothelial cell proliferation, and the inhibitory effect of increased superoxide due to hyperglycemia can be reversed by CuZnSOD overexpression.
Femtosecond laser ablation particle introduction to a liquid sampling-atmospheric pressure glow discharge ionization source

This work describes the use of a compact, liquid sampling–atmospheric pressure glow discharge (LS-APGD) ionization source to ionize metal particles within a laser ablation aerosol. Mass analysis was performed with a Thermo Scientific Exactive Mass Spectrometer which utilizes an orbitrap mass analyzer capable of producing mass resolution exceeding m/Δm > 160,000. The LS-APGD source generates a low-power plasma between the surface of an electrolytic solution flowing at several μl min−1 through a fused silica capillary and a counter electrode consisting of a stainless steel capillary employed to deliver the laser ablation particles into the plasma. Sample particles of approximately 100 nm were generated with an Applied Spectra femtosecond laser located remotely and transported through 25 meters of polyurethane tubing by means of argon carrier gas. Samples consisted of an oxygen free copper shard, a disk of solder, and a one-cent U.S. coin. Analyte signal onset was readily detectable relative to the background signal produced by the carrier gas alone. The high mass resolution capability of the orbitrap mass spectrometer was demonstrated on the solder sample with resolution exceeding 90,000 for Pb and 160,000 for Cu. In addition, results from a laser ablation depth-profiling experiment of a one cent coin revealed retention of the relative locations of the ∼10 μm copper cladding and zinc rich bulk layers.
The temperature of a vibrated granular gas

The temperature of a granular medium is defined, in a manner analogous to that of a molecular gas, as the root mean squared kinetic energy of the grains. Using a novel two-layer granular experiment, we have made a systematic study of the granular temperature as a function of driving parameters in order to determine whether the behavior of the granular temperature is truly analogous to the temperature of a molecular gas. By examining the behavior of this particular system in detail, where two fluctuating granular media are in thermal contact, we also suggest general conditions under which such analogies can be extended to other driven systems.
Oncogenic Ras and its role in tumor cell invasion and metastasis

The processes by which cancer cells leave the tumor and enter adjacent tissue is known as invasion, whereas metastasis refers to secondary tumor colonization of tissue at a distance from the primary lesion. These two events are the most lethal of cancer phenomena and the signaling mechanisms that govern them are complex. The Ras signaling pathways are well represented in their involvement in tumor initiation, but considerably less is known about their contribution to invasion and metastasis. In this review, we discuss the current evidence for mutant Ras proteins as significant players in these aspects of cancer progression.