cssi/SciSciGPT-SciSciNet huggingface dataset:
Optimization of gas turbine combustor performance throughout the duty cycle

A gas turbine combustor must operate over a range of load conditions (duty cycle) in both stationary-power and propulsion applications. With a static geometry combustor, flow splits are fixed between the dome and wall jets, and the performance optimization is either a compromise over a range of loading or possible only at one operating condition. Future designs may be required to adopt variable geometry or alternate flow modification techniques to secure peak performance throughout the duty cycle. To accomodate this variation, a feedback controller will be required. In this paper, an active control methodology is introduced in conjunction with geometric articulation to establish optimal conditions for each load setting throughout a given duty cycle. The algorithm emplogyed is derived from the hill-climbing and downhill simplex methods. This controller successfully identifies the geometric configurations of optimal performance and rapidly selects the optimal operating configuration for all the loads investigated. This controller/combustor combination allows for rapid parametric optimization at each operating condition. In this study, both combustion efficiency and emissions of oxides of nitrogen are optimized. The combustor explored has two distinct response modes. Representative cases, one for each response mode, are illustrated. With the control algorithm used, regions of combustion instability are avoided for all the conditions explored.
Down-regulation of steroidogenic acute regulatory (StAR) protein in rat Leydig cells : implications for regulation of testosterone production during aging

Aging in rats is associated with reduced synthesis of steroid hormones. In the present study, response to gonadotropin and Bt2cAMP in vitro was significantly reduced in Leydig cells isolated from old versus young rats. StAR protein levels were similarly decreased in interstitial cells prepared from the testes of old rats.
A review of: “Electronic Materials: The Oligomer Approach, edited by K. Müllen and G. Wegner, Wiley-VCH, Weinheim, 1998; ISBN 3–527–29438–4; xxvii + 599 pages; DM 398.00; sFr 354.00”

(2000). A review of: “Electronic Materials: The Oligomer Approach”, edited by K. Mullen and G. Wegner, Wiley-VCH, Weinheim, 1998; ISBN 3-527-29438-4; xxvii +599 pages; DM 398.00; sFr 354.00. Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals: Vol. 338, No. 1, pp. 277-278.
Hibernation induction trigger reduces hypoxic damage of swine skeletal muscle

A link between the cardioprotective benefits of pharmacological preconditioning and natural mammalian hibernation is considered to involve the cellular activation of opioid receptors and subsequent opening of K(ATP) channels. In previous studies, we have demonstrated the protective effects of specific delta-opioid agonists against porcine cardiac ischemia/reperfusion injury. We hypothesize here that preincubation with hibernation induction trigger (HIT) should confer a similar protection in skeletal muscles. Therefore, muscle bundles from swine were pretreated with plasma from hibernating woodchucks (HWP) for 30 min, then exposed to hypoxia for 90 min and reoxygenation for 120 min. Stimulated twitch forces were assessed. The functional effects of pretreatment with nonhibernation (summer) woodchuck plasma, a K(ATP) blocker, or opioid antagonist were also studied. During the reoxygenation period, significantly greater force recoveries were observed only for bundles pretreated with HWP; this response was blocked by naloxone (P < 0.05). We conclude that HIT pretreatment could be used to confer protection against hypoxia/reperfusion injury of skeletal muscles of nonhibernators; it could potentially be utilized to prevent injury during surgical procedures requiring ischemia.
Mechanism of action of choleragen and E. coli heat-labile enterotoxin: activation of adenylate cyclase by ADP-ribosylation.

Choleragen exerts its effects on cells through the activation of adenylate cyclase. The initial event appears to be the binding of the B subunit of the toxin to ganglioside GM1 on the cell surface, following which there is a delay prior to activation of adenylate cyclase. Patching and capping of the toxin on the cell surface, perhaps involved in the internalization of the enzymatically active subunit, may be occuring during this time. The activation of adenylate cyclase, which is catalyzed by the A1 peptide of choleragen, does not require the B subunit or ganglioside GM1. The A1 peptide catalyzes the transfer of ADP-ribose from NAD to an amino acid, probably arginine, in a 42 000 dalton membrane protein. This protein appears to be the GTP-binding component (or G/F factor) of the adenylate cyclase system and is cruical to the regulation of cyclase activity by hormones such as epinephrine. ADP-ribosylation of the G/F factor is enhanced by GTP and, in some systems, by a cytosolic factor. GTP is also required for stabilization and optimal catalytic function of the choleragen-activated cyclase. Calmodulin, a calcium-binding protein, is necessary for expression of catalytic activity of the toxin-activated adenylate cyclase in brain and other tissues.
Determination of fault friction from reactivation of abyssal-hill faults in subduction zones

Abyssal-hill faults are reactivated on the outer slope of trenches when they strike within 25° from trench parallel; otherwise, new faults form parallel to the trench. We use the observed transition angle (25°) and a three-dimensional failure analysis to determine the coeffi cient of friction on reactivated abyssal-hill faults. The stress state in the outer slope is modeled as the superposition of the overburden stress and bending-induced plane strain deformation. If new trench-parallel faults fail according to a linear failure relationship with no cohesion, then determination of the coeffi cient of sliding friction (μs) on reactivated faults is independent of the absolute value of the principal stresses and depends only on the Poisson ratio of the crust and the slope of the failure law for new faults (μf). We fi nd that reactivated faults, dipping at 45°, are ~30% weaker than surrounding crust (e.g., μs = 0.6 for μf = 0.85). These results suggest that the variation in the strength of oceanic crust due to the seafl oor spreading fabric is small, and that the coeffi cient of sliding friction on oceanic faults is consistent with that observed in the laboratory.
Fluorometric scanning of polyacrylamide gels

Abstract A gel scanning technique that measures the quench of N-allyl-DANSA fluorescence by amido schwarz stained protein bands had the potential capability of about fifty times the sensitivity of absorption densitometric techniques. The preparation of the fluorescent polyacrylamide gels was straightforward and their electrophoretic resolving and storage properties compared favorably with standard gels. An inexpensive modification of a common commercial fluorometer was described for scanning these gels.
Belonging to the world: Cosmopolitanism in geographic contexts

Abstract The notion of cosmopolitanism is today gaining new relevance in attempts to understand how globalization in an increasingly interdependent world-society is affecting traditional identities, including that of the nation. We focus on a positive definition of cosmopolitanism as a sense of belonging to “the world as a whole”, expressed in responses to a question from the World Values Surveys (WVS) 1995–1997. In building a multilevel statistical model of the 21 national contexts of societal attitudes and values surrounding cosmopolitanism, we inject empirical analysis into what has, until now, been a largely rhetorical field of scholarship. Because the data are collected hierarchically, with individuals clustered into regions in turn grouped into countries, the model allows for the consideration of different concepts of cosmopolitanism across geographic contexts. A greater likelihood of cosmopolitan identification is found among individuals who are environmentalist, less patriotic, politically active, with higher levels of education, youthful, and a positive orientation to living among immigrants in places where relatively more immigrants reside. Respondents from countries in the former Soviet Union show a significantly higher sense of belonging to the world as a whole, a difference attributed to the lack of confidence in the post-Communist regimes of these states in the 1990s.
Syngap1 haploinsufficiency damages a postnatal critical period of pyramidal cell structural maturation linked to cortical circuit assembly

Abstract Background Genetic haploinsufficiency of SYNGAP1/Syngap1 commonly occurs in developmental brain disorders, such as intellectual disability, epilepsy, schizophrenia, and autism spectrum disorder. Thus, studying mouse models of Syngap1 haploinsufficiency may uncover pathologic developmental processes common among distinct brain disorders. Methods A Syngap1 haploinsufficiency model was used to explore the relationship between critical period dendritic spine abnormalities, cortical circuit assembly, and the window for genetic rescue to understand how damaging mutations disrupt key substrates of mouse brain development. Results Syngap1 mutations broadly disrupted a developmentally sensitive period that corresponded to the period of heightened postnatal cortical synaptogenesis. Pathogenic Syngap1 mutations caused a coordinated acceleration of dendrite elongation and spine morphogenesis and pruning of these structures in neonatal cortical pyramidal neurons. These mutations also prevented a form of developmental structural plasticity associated with experience-dependent reorganization of brain circuits. Consistent with these findings, Syngap1 mutant mice displayed an altered pattern of long-distance synaptic inputs into a cortical area important for cognition. Interestingly, the ability to genetically improve the behavioral endophenotype of Syngap1 mice decreased slowly over postnatal development and mapped onto the developmental period of coordinated dendritic insults. Conclusions Pathogenic Syngap1 mutations have a profound impact on the dynamics and structural integrity of pyramidal cell postsynaptic structures known to guide the de novo wiring of nascent cortical circuits. These findings support the idea that disrupted critical periods of dendritic growth and spine plasticity may be a common pathologic process in developmental brain disorders.
Heteroscedastic Global Tests that the Regression Parameters for Two or More Independent Groups are Identical

Simulation results are reported on methods that allow both within group and between group heteroscedasticity when testing the hypothesis that independent groups have identical regression parameters. The methods are based on a combination of extant techniques, but their finite-sample properties have not been studied. Included are results on the impact of removing all leverage points or just bad leverage points. The method used to identify leverage points can be important and can improve control over the Type I error probability. Results are illustrated using data from the Well Elderly II study.
STARCH GEL ELECTROPHORESIS OF ENZYMES FROM NINE SPECIES OF POLYPORUS

A B S T R A C T Taxonomic relationships among 22 isolates of nine species of the wood-rotting fungus, Polyporus, were examined by starch gel electrophoresis, coupled with histochemical staining procedures. Crude extracts of 21-day cultures grown on malt extract agar were subjected to electrophoresis for 3 hr at a constant current of 25 ma. Esterase, peroxidase, catechol oxidase, galactose dehydrogenase, acid phosphatase, and alkaline phosphatase banding patterns were analyzed. With each enzyme, the bands for each isolate were compared with those for other isolates of the same species and for isolates of other species. A closer relationship was found in the banding patterns for different isolates of a single species than among isolates of different species. This technique may prove valuable for the evaluation of taxonomic differences among these wood-rotting fungi. THE SYSTEMATICS OF wood-rotting fungi has been examined by mycologists for many years, and yet many of today's leading taxonomists are in disagreement as to the delimitations of the genera of Polyporaceae. In particular, taxonomic and phylogenetic relationships among the species of Polyporus have presented problems to taxonomists who use morphological, cytological, cultural, and physiological methods of classification. Most contemporary mycologists follow the system of classification by Overholts (1953), who divided the family into 13 genera. Based upon this classification system, he recognized 162 species in the genus Polyporus. Prominent European mycologists, such as M. A. Donk, follow the system of classification of Bessey (1950), or variations
Practical pathology perspectives for minimally invasive hyperthermic medical devices

Currently, hyperthermic-based minimally invasive medical devices are available for the treatment of dysfunctional and neoplastic tissues in a variety of organ systems. These therapies employ a spectrum of modalities for delivering heat energy to the targeted tissue, including radiofrequency/microwave, high intensity focused ultrasound, conductive/convective sources and others. While differences in energy transfer and organ systems exist, hyperthermic treatment sites show a spectrum of changes that intimately correlate with the thermal history generated in the tissue (temperature-time dependence). As a result, these hyperthermic medical technologies can be viewed using a "gradient" approach. First, the thermal applications themselves can be globally categorized along a high-dose ablation to low-dose ablation to lowdose non-ablative rejuvenating slope. Second, the resultant tissue changes can be viewed along a decreasing thermal dose gradient from thermally/heat-fixed tissue necrosis to coagulative tissue necrosis to partial tissue necrosis (transition zone) to subtle non-necrotizing tissue changes. Finally, a gradient of cellular and structural protein denaturation is present, especially within the transition zone and adjacent viable tissue region. A hyperthermic treatment's location along these gradients depends more on the overall thermal history it generates than the amount of energy it deposits into the tissue. The features of these gradients are highlighted to provide a better understanding of hyperthermic device associated tissue changes and their associated healing responses.
Anisotropy in surface ace diffusion: Oxygen, hydrogen, and deuterium on the (110) plane of tungsten

Abstract The field emission fluctuation method of measuring surface diffusion coefficients has been extended to a determination of anisotropy by using as probehole a long, thin, rectangular slit, which can be rotated in situ. For oxygen on W(110), D (110) D (100) = 2 (where the subscripts indicate directions in the plane) under almost all conditions of coverage and temperature. This is the expected result if actual jumps occur along (111) directions. For 1H and 2H very little anisotropy was found for θ > 0.25, and D (110) D (100) ⩽1.3 at θ ⩽ 0.25. This result is tentatively explained by symmetry breaking: It has recently been found by Estrup that H adsorption causes surface reconstruction consisting of a shifting of the top layer along the (110) direction. This Jahn-Teller effect leads to inequivalence of the two asymmetric bridge sites at the ends of the “hourglass” wells on (110) and this can be shown to favor diffusion along (100) over that along (110), relative to the unreconstructed plane, thus decreasing D (110) D (100) . Anisotropies in the mean square fluctuations were also seen in all cases. These can be explained by assuming that the correlation lengths of the fluctuations differ along the (110) and (100) directions and that the correlation length along the former is at least 40 A. A mean field theory calculation in terms of nearest, next nearest and next-next nearest neighbor interaction energies is carried out, and it is shown that values of these parameters in good agreement with those invoked to explain the O/W(110) phase diagram and the increase in activation energies of diffusion for that system give the required correlation lengths and anisotropies. In particular it is shown that the anisotropies in interactions along the (110) and (100) directions are largely responsible for the mean square fluctuation anisotropy for oxygen. For 1H and 2H similar but even larger mean square fluctuation anisotropies are found, and vary more strongly with coverage and temperature than for oxygen, suggesting even more complex interactions.
Some Coriolis slurry erosion test developments

Abstract The Coriolis test has developed into a useful way of evaluating the slurry erosion behaviour of materials. Wear mapping has revealed some sensitivity to test conditions so both the tester and test procedures continue to evolve. Experiments with very dilute model slurries comprising a ‘pinch’ of glass beads, or a single glass bead, gave information on bead contact depth and normal component of impingement velocities which confirmed previous theoretical predictions that erodent particles interact with the specimen in a series of low angle impacts. The superior discriminating ability of the Coriolis slurry erosion test is due to the lower interaction intensity of erodent particles with target surfaces compared to that in slurry jet testing.
Enhancing the Conversion Efficiency of Second Harmonic Generation Using Counterpropagating Light

We have observed modulation of the conversion efficiency of second harmonic generation by 1-2% of the spectral intensity using a single counterpropagating pulse to locally disrupt the phase of the nonlinear polarization wave.
Gas Condensate Well Test Analysis Using a Single-Phase Analogy

This paper shows that a simple, single-phase analogy using a standard dry gas pseudopressure transformation in interpreting transient buildup pressure data from a gas condensate well gives a good estimation of permeability. Under certain conditions, this method gives good estimates of damage skin, too. These results are not affected by average reservoir pressure. We used a commercial fluid PVT package and an EOSbased compositional simulator to characterize the phase behavior of retrograde gases during reservoir depletion, to compare gas and condensate PVT properties in situ and at lab conditions, and to model a vertical well under varying conditions. Then we analyzed the simulated buildup transient pressure by using a single-phase analogy incorporating a radially composite model and compared the results with reservoir simulator inputs and outputs. The numerical experiments using three actual fluid samples show that, during reservoir depletion, the vapor properties in situ are a function of pressure only, and correlate very well with z factor, gas molar density and viscosity obtained in lab constant composition expansion (CCE). The condensate PVT properties in situ depend on pressure, production mode and reservoir properties. But the effects of variables other than pressure are usually small and are constrained within a certain pressure range. As a rule, the leaner the retrograde gas, the smaller the deviations. As a practical matter, the correlations between condensate oil PVT properties obtained from lab CCE and the values in situ are also quite acceptable. Our reservoir simulation showed that the pressure buildup responses can be classified into two types. In the first type, the shape of the pressure derivative suggests a well in a radially composite two-zone reservoir. In the second type, the pressure derivative suggests a well in a radial three-zone reservoir. Our interpretation of 30 simulated cases using a radially composite two-zone model shows that a single-phase analogy gives a good estimation of permeability but underestimates condensate bank size. We cannot estimate damage skin from the first type of pressure response, but the estimation from the second type is acceptable.
Sorbent Wicking Device for Sampling Hydrophobic Organic Compounds in Unsaturated Soil Pore Water. I: Design and Hydraulic Characteristics

The hydraulic characteristics of horizontally installed sorbent wick sampling devices were evaluated through wick tracer studies and laboratory soil column experiments to assess the influence of horizontal wick length and sampler interface design on sampling pore water in unsaturated soils. The nominal sampler design consisted of a cylindrical porous metal interface packed with granular-activated carbon encapsulating the end of a fiberglass wick that extended 100 cm horizontally from the interface before dropping 100 cm vertically to a collection vessel. The maximum sampling rate of horizontally installed wick systems declines exponentially with increasing horizontal wick length, while the vertical length influences the range of soil–water pressures that may be sampled. The nominal design sampled pore water from clay loam laboratory columns at 8 to 14 mL h−1 under steady-state infiltration conditions and 2 to 5 mL h−1 under draining conditions across a −10 to −45 cm H2 O soil–water pressure range. Samplin...
Brief report: Initial psychometric properties of the everyday discrimination scale in black adolescents ☆

This study explored select psychometric properties of the Everyday Discrimination Scale in 120 Black adolescents (65 males and 55 females). Youth completed the Everyday Discrimination Scale and the Child Behaviour Checklist-Youth Self-Report Form. A t-test analysis revealed that Everyday Discrimination Scale scores were not significantly different for males and females (p > 0.18). The alpha reliability coefficient was 0.87, with item-total correlations that ranged from 0.50 to 0.70 (mean=0.61). The split-half reliability was 0.83 (p < 0.0001). A principal component analysis yielded one factor, which accounted for approximately 49% of the standardized variance. Correlation analyses indicated that the Everyday Discrimination Scale score was significantly related to internalizing and externalizing symptoms (ps < 0.0002).
Parameters affecting the liposome-mediated insertion of RNA into eucaryotic cells in vitro.

Abstract The effect of various parameters on the liposome-mediated insertion of RNA into eucaryotic cells in vitro has been studied. Maximization of the insertion of liposome-encapsulated RNA into cells was approached at three levels: (1) alteration of liposome membrane composition, (2) alteration of the recipient cell membrane, and (3) manipulation of the conditions of liposome-cell cocultivation. (1) Changes in liposome membrane composition failed to affect the amount of RNA sequestered within liposomes but did alter the efficiency and mode of liposome uptake by human epithelial carcinoma cells, rabbit spleen lymphocytes, and carrot protoplasts. Addition of lysolecithin to the liposome membrane enhanced the cellular uptake of liposome-sequestered RNA by a “fusion” mechanism (uptake in the presence of cytochalasin B), while addition of cholesterol was inhibitory. (2) Uptake of liposome-sequestered RNA was enhanced when (a) cells were in the mitotic phase of the cell cycle; (b) cells were pretreated with cholesterol-free liposomes; and (c) cells were treated with Piracetam (2-oxo-1-pyrrolidine acetamide). The increased cellular uptake of liposomes appeared in most cases to be due to enhanced cell membrane fluidity. (3) Liposome uptake by cells was directly proportional to the time of liposome-cell cocultivation and to cell number. Increasing doses of liposomes resulted in a reduction of the percentage of RNA uptake, possibly due to a saturation phenomenon. When several of the investigated parameters were simultaneously maximized, as high as 20% of the liposome-sequestered RNA was inserted into human epithelial carcinoma cells.
The reaction of diphosphopyridine nucleotide and related pyridinium salts with alkali

Abstract Spectra and difference spectra are presented which result from the reaction of hydroxyl ions with diphosphopyridine nucleotide (DPN), nicotinamide mononucleotide, nicotinamide riboside, and N1-methylnicotinamide. The temporal relationships between the spectral changes, fluorescence, and chemical and enzymic reactivity of DPN are described. These data suggest that the initial association of DPN and hydroxyl ions is to form a charge transfer complex. Subsequently, the hydroxyl ion is added to the pyridinium ring forming a dihydropyridine, which is acid labile.
High-Pressure Polymorph of Thulium: An X-ray Diffraction Study.

An x-ray diffractiotn study of thulium at room temperature and high pressure by means of a diamond-anvil press has shown that thulium transforms from a hexagonal close-packed structure to the samarium type, as other rareearth elements (gadolinium, terbium, dysprosium, and holmium) do. Unlike the other rare-earth elements, thulium (hexagonal close-packed) has an axial ratio (c/a) that is independent of pressure within experimental error and the transition is reversible. The transition occurs with increasing pressure in the range of 60 to 116 kilobars. The lattice paralieters of the samarium-type phase of thulium at about 116 kilobars are a = 3.327 ± 0.005 angstroms and c = 23.48 ± 0.04 angstroms, and the volume change at the transition is estimated to be - 0.5 percent of the volume of the hexagonal close-packed phase at the transition.
“We Are Like Prey” How People Negotiate a Violent Community in Trinidad and Tobago

Urban communities in the Republic of Trinidad and Tobago have transformed into war zones; citizens report that crime and violence are the primary problems incapacitating their communities . Researc...
Descending propriospinal neurons in normal and spinal cord-transected lamprey.

The organization and distribution of propriospinal neurons with descending axons were determined via retrograde HRP labeling in normal lamprey and in animals that had behaviorally recovered for various times (4, 8, 16, and 32 weeks) following transection of the rostral spinal cord. In normal animals, descending propriospinal neurons were found in the rostral, middle, and caudal spinal cord. Theoretical analysis indicated that the majority of these neurons had relatively short axons ( 30 mm). In spinal cord-transected animals, with increasing recovery times there was a gradual increase in the numbers of labeled propriospinal neurons below the lesion with short- to moderate-length descending axons. The distribution of descending propriospinal neurons and the possible plasticity in this system following spinal cord transection are discussed with regard to activation of spinal motor networks and initiation of locomotor behavior.
Determination of arsenic in food and dietary supplement standard reference materials by neutron activation analysis

Arsenic was measured in food and dietary supplement standard reference materials by neutron activation analysis for the purpose of assigning certified or reference As mass fractions and to assess material homogeneity. Instrumental neutron activation analysis was used to value assign As in candidate SRM 3532 Calcium Dietary Supplement and candidate SRM 3262 Hypericum perforatum (St. John’s Wort) Aerial Parts down to about 100 μg/kg. Values were also determined for two additional candidate St. John’s Wort SRMs with As mass fractions <100 μg/kg. The presence of significant amounts of 24Na and 82Br limited the reproducibility of the method below 100 μg/kg. For measurement of lower As mass fractions, a radiochemical neutron activation analysis method with extraction of As3+ into diethyl-dithiocarbamate in chloroform and detection limits down to 0.1 μg/kg. As was used to value-assign As mass fractions for SRM 3280 Multivitamin/Multielement Tablets and for candidate SRM 3233 Fortified Breakfast Cereal, and at <10 μg/kg in candidate SRM 1845a Whole Egg Powder.
The stochastic duel with time‐dependent hit probabilities

The fundamental stochastic duel considers two opponents who fire at each other at either random continuous or fixed-time intervals with a constant hit probability on each round fired. Each starts with an unloaded weapon, unlimited ammunition, and unlimited time. The first to hit wins. In this article we extend the theory to the case where hit probabilities are functions of the time since the duel began. First, the marksman firing at a passive target is considered and the characteristic function of the time to a hit is developed. Then, the probability of a given side winning the duel is derived. General solutions for a wide class of hit probability functions are derived. Specific examples of both the marksman and the duel problem are given.
Eigenvectors of the inertia tensor and perceiving the orientation of a hand-held object by dynamic touch.

Subjects wielded an object, hidden from view, and reported the orientation in which the object was positioned in the hand. The object consisted of a stem with two branches forming a V attached perpendicularly to the stem’s distal end. The branches were differentially weighted so that the same spatial orientation of the object was associated with different orientations of its principal (symmetry) axes or eigenvectors. Perceived orientation was found to be dependent on the eigenvectors of the object’s inertia tensor, computed about the point of rotation in the wrist, rather than on its spatial orientation. The results underscore the significance of the inertia tensor to understanding the perception of spatial properties by dynamic touch.
Determination of the concentration of SF6 in an accelerator gas mixture by measuring the velocity of sound

Abstract A simple and reliable method for determining the concentration of SF 6 in an accelerator gas mixture with N 2 and CO 2 is described. The technique makes use of the low velocity of sound in SF 6 (approximately 1 3 that of air). The sound velocity of the mixture is determined by measuring the spacing of acoustic resonances in a tube filled with the gas. Data from standard gas mixtures containing 0–10% SF 6 are presented, showing that the technique is accurate to approximately 0.5% absolute.
EFFECT OF MONOVALENT CATIONS ON THE ADENOSINETRIPHOSPHATASE OF A SKELETAL MUSCLE MICROSOMAL PREPARATION.

Summary 1. The possible involvement of Mg2+-dependent adenosinetriphosphatase (EC 3.6.1.4) of skeletal muscle microsomes in the process of active transport of monovalent cations was studied. 2. The adenosinetriphosphatase activity of a light microsomal preparation of rabbit skeletal muscle was stimulated by either Na+, K+, NH4+ or Rb+. Cs+ and Li+ inhibited the enzymic activity both in the presence and absenpe of stimulating cations. 3. The simultaneous presence of Na+ and K+ did not cause any additional activation beyond that obtained by either ion alone. Also, ouabain had no effect on the enzymic activity. It was, therefore, concluded that a correlation between the adenosinetriphosphatase and active transport of Na+ and K+ was not apparent. 4. Na+ and K+ were found to inhibit the adenosinetriphosphate-dependent Ca2+-binding by the light microsomes. A possible relation of Na+, K+-activated adenosinetriphosphatase to Na+, K+-inhibited Ca2+-binding was suggested.
Reconstructing the surface of arthropod immunocytes from serial sections

There has been little work in developing comprehensive research tools which would allow the researcher to study the complete interval and external structure of the cell as well as automatically classifying the cell structure. The authors describe an effort to combine these three functions into one computer-based imaging system. A description is given of the first part of this system, which is used to display and rotate three-dimensional reconstructions of the exterior of arthropod immunocytes from serial sections. >
Interacting Virus Abundance and Transmission Intensity Underlie Tomato Spotted Wilt Virus Incidence: An Example Weather-Based Model for Cultivated Tobacco

Through a modeling approach, we investigated weather factors that affect the summer incidence of Tomato spotted wilt virus (TSWV), a virus vectored exclusively by thrips, in cultivated tobacco. Aspects of thrips and plant biology that affect disease spread were treated as functions of weather, leading to a model of disease incidence informed by thrips and plant biology, and dependent on weather input variables. We found that disease incidence during the summer was influenced by weather affecting thrips activity during the preceding year, especially during a time when thrips transmit TSWV to and from the plant hosts that constitute the virus’ natural reservoir. We identified an interaction between spring precipitation and earlier weather affecting thrips, relating this to virus abundance and transmission intensity as interacting factors affecting disease incidence. Throughout, weather is the basic driver of epidemiology in the system, and our findings allowed us to detect associations between atypically high- or low-incidence years and the local climatic deviations from normal weather patterns, brought about by El Nino Southern Oscillation transitions.
Anti-idiotypic antibody identifies the cellular receptor of reovirus type 3

The binding and subsequent infectivity of reovirus to target cells are mediated by interaction with specific cell surface viral receptors. To gain a more detailed understanding of the biochemistry of the reovirus receptor and the cellular consequences of viral attachment, we have studied the binding of type 3 reovirus (Dearing strain) in a quantitative manner utilizing an antiidiotypic antibody probe. A syngeneic monoclonal antiidiotypic antibody (87.92.6) was prepared by immunization with hybridoma cells which secrete an antireovirus hemagglutinin-specific antibody. This antiidiotypic antibody was previously shown to specifically recognize the cell surface receptor for reovirus type 3. In this report, we demonstrate that antiidiotype mimicked reovirus tropism in binding to murine thymomas; antiidiotype inhibited the binding of reovirus to specific targets, but not the binding of anti-H-2; and cross linking of receptor-bound antiidiotype by antiimmunoglobulin induced patching, but not capping of reovirus receptors. Utilizing radiolabeled antiidiotype, we next quantitate the number of reovirus receptors on R1.1 and YAC thymoma cells and, finally, report on the preliminary identification of the reovirus receptor as a 67,000-Da membrane glycoprotein.
A Possible Role for the High Mobility Group Box Transcription Factor Tcf-4 in Vertebrate Gut Epithelial Cell Differentiation

The Wingless (Wg)/Wnt signaling pathway activates High Mobility Group (HMG)-box transcription factors of the T-cell Factor (Tcf)/Lymphoid Enhancer Factor (LEF) subfamily and mediates diverse functions in development, possibly including endoderm and gut differentiation. Determinants of tissue specificity in the response to Wg/Wnt signaling remain unknown. We have identified Tcf-4 as the predominant Tcf/LEF factor in the developing mouse gut. During fetal development, Tcf-4 mRNA expression is restricted to gut epithelium and specific regions of the brain, the thalamus and roof of the midbrain. In adults, expression is widespread, with highest levels observed in the liver, an endodermally derived organ, and persists in the gastrointestinal tract. Murine Tcf-4 has multiple RNA splice variants with consequently significant heterogeneity in sequences 3′ to the HMG box. Microinjection of mRNA or plasmid DNA encoding Tcf-4 into Xenopus embryos results in ectopic expression of molecular markers of endoderm and differentiated gut epithelium in isolated animal cap explants. Taken together, these findings point to a potentially important function for Tcf-4 in development of the vertebrate gastrointestinal tract.
NIAM-Deficient Mice Are Predisposed to the Development of Proliferative Lesions including B-Cell Lymphomas

Nuclear Interactor of ARF and Mdm2 (NIAM, gene designation Tbrg1) is a largely unstudied inhibitor of cell proliferation that helps maintain chromosomal stability. It is a novel activator of the ARF-Mdm2-Tip60-p53 tumor suppressor pathway as well as other undefined pathways important for genome maintenance. To examine its predicted role as a tumor suppressor, we generated NIAM mutant (NIAM(m/m)) mice homozygous for a β-galactosidase expressing gene-trap cassette in the endogenous gene. The mutant mice expressed significantly lower levels of NIAM protein in tissues compared to wild-type animals. Fifty percent of aged NIAM deficient mice (14 to 21 months) developed proliferative lesions, including a uterine hemangioma, pulmonary papillary adenoma, and a Harderian gland adenoma. No age-matched wild-type or NIAM(+/m) heterozygous animals developed lesions. In the spleen, NIAM(m/m) mice had prominent white pulp expansion which correlated with enhanced increased reactive lymphoid hyperplasia and evidence of systemic inflammation. Notably, 17% of NIAM mutant mice had splenic white pulp features indicating early B-cell lymphoma. This correlated with selective expansion of marginal zone B cells in the spleens of younger, tumor-free NIAM-deficient mice. Unexpectedly, basal p53 expression and activity was largely unaffected by NIAM loss in isolated splenic B cells. In sum, NIAM down-regulation in vivo results in a significant predisposition to developing benign tumors or early stage cancers. These mice represent an outstanding platform for dissecting NIAM's role in tumorigenesis and various anti-cancer pathways, including p53 signaling.
Population response patterns of distinct neuronal subsets in hindlimb sensorimotor cerebral cortex of the domestic cat

Abstract Distinct neuronal subsets were identified by microelectrode recordings taken from the hindpaw focus of sensorimotor cerebral cortex of cats anesthetized with chloralose. The hindpaw focus was located squarely within cytoarchitectonic field 3b of primary somatosensory (SmI) cortex. The population of neurons within this region was similar to that found in the primary motor (MsI) cortex forepaw focus of field 4γ, but different from that in the forepaw focus of field 3b. The vast majority of the neurons isolated (98.5%) were identified either as small-field (sa) neurons or widefield (m) neurons; the others were either sb or sc neurons. The population response patterns of the sa and m neurons were studied, and found to be very similar to those of sa and m neurons in forelimb sensorimotor cortex. For each neuronal subset, spike density distributions were constructed as a joint function of time, following 1/sec electrical shocks to the central footpads, and depth within the cortex. The population response patterns of the two subsets were strikingly different. Following stimulation of the contralateral hindpaw, the sa neuron activity reached a maximum 16.0 msec after the stimulus, at a depth of 0.6 mm below the pial surface; the m neuron activity peaked 4 msec later and 0.4 mm deeper. The response profiles of the m neurons produced by stimulation of the other three (off-focus) paws were all similar to one another, but were shifted relative to each other in time; these patterns showed much greater temporal dispersion than the pattern produced by contralateral hindpaw stimulation. All the off-focus m neuron profiles showed a small, early peak of activity deep within the cortex, and a larger, later peak at intermediate depths. The population response patterns of both neuronal subsets are discussed as possible substrates for encoding information about various stimulus properties; it is argued that the sa neurons are much better suited to encode stimulus location than the m neurons. The temporal relationship between the time courses of activity of the sa and m neurons and the concomitant surface primary response was similar to that obtained for sa and m neurons within forepaw tissue. The interconnections between thalamus and cortex and among the different subsets of cerebral neurons, as deduced from study of the postcruciate forepaw focus (field 4γ), were found to be applicable to the hindpaw focus (field 3b) as well. It is argued that cytoarchitectonic field 3b is probably not devoted to a single function that might be characterized as sensory or motor.
Sleep in children with cancer: case review of 70 children evaluated in a comprehensive pediatric sleep center

The goal of this study was to characterize the sleep problems of children with cancer who were referred for a comprehensive sleep evaluation. A retrospective case series review was conducted of all children with cancer referred to the pediatric sleep clinic from 1994 to 2009 for evaluation of a sleep problem. Seventy children were seen and evaluated during this interval; all had a complete sleep history taken, and further objective sleep evaluations were performed as part of their evaluation only when clinically indicated. An overnight polysomnogram was performed in 53 children. In 36 children with a history of excessive daytime sleepiness (EDS), a multiple sleep latency study was performed the following day. Seven children had a 3–4-week actigraphic study. Children with neoplasms of central nervous system (CNS) involving the hypothalamus, thalamus, and brainstem were the most commonly referred children and had the most frequent and severe sleep problems. Excessive daytime sleepiness was the most common sleep problem, seen in 60% of children with cancer and in 80% of children with CNS neoplasms involving the hypothalamus, thalamus, and brainstem. Sleep disordered breathing (SDB) was present in 40% of the entire group of children with cancer and 46% of children with neoplasms involving the hypothalamus, thalamus, and brainstem. Children with CNS neoplasms often had more than one sleep problem, most commonly EDS and SDB. In these children, correction of the SDB often did not eliminate the EDS. In children with leukemia, insomnia was the most common sleep problem identified, present in 39%. The causes of the sleep problems were varied and included neurologic injury caused by the neoplasm and/or the CNS-directed treatments; seizures, adenotonsillar hypertrophy, medication side effects, obesity, pain, anxiety, and drug abuse. Some of the sleep problems were present before the diagnosis of cancer, though most developed after treatment was begun. A wide range of intervention strategies were utilized to address the sleep problems and included sleep hygiene/sleep restriction, behavioral counseling, continuous positive airway pressure, bilevel positive airway pressure, tracheotomy with and without a ventilator, diaphragmatic pacers, sedative hypnotics, stimulants, anticonvulsants, and antidepressants. When the sleep problems and their causes were correctly identified and treatments were directed to the specific cause of the problem, the treatments were generally successful. The sleep problems of children with cancer span the full spectrum of clinical sleep disorders (hypersomnia, sleep disordered breathing, insomnia, parasomnias, and circadian rhythm disorders) and are often present in combinations. Children with neoplasms involving the brainstem, thalamus, and hypothalamus were the most frequently referred for a sleep evaluation, and their sleep problems were most commonly EDS or SDB. Expertise in pediatric sleep disorders can be a valuable resource in the ongoing care of children with cancer.
Women With Disabilities in the Developing World Arenas for Policy Revision and Programmatic Change

It has become standard practice to call attention to the double discrimination against both gender and disability under which women with disability labor. If women with disabilities universally find themselves at greater disadvantage because of these prejudices, their lives are often even more severely curtailed in much of the developing world, where poverty and traditionally negative attitudes toward women and disability are widely, although by no means universally, found. This paper is not intended to catalog every known variation in beliefs confronted by women with disabilities, but rather to provide an overview of some of the most prominent issues faced by women with disabilities in the developing world. It is written in the hopes that researchers from a variety of fields may become interested in some of the many areas about women with disabilities in developing nations about which we currently know so little.
Measurement of mechanical properties of alkaline-earth metal hexaboride one-dimensional nanostructures by nanoindentation

The divalent alkaline-earth metal hexaboride MB6 (M = Ca, Sr, Ba) one-dimensional (1D) nanostructures are promising n-type thermoelectric materials for high temperature power generation. Understanding fundamental physical and mechanical properties of these new nanostructures is critical for their future applications. Current work focuses on reliable study of mechanical properties of MB6 1D nanostructures by nanoindentation. Factors affecting the measured nanostructure-on-substrate system modulus, such as the stiffness of a supporting substrate, the width and cross section of a nanostructure, the interaction between a nanostructure and a substrate, were systematically studied by both experimental investigation and numerical simulation. The intrinsic modulus of a nanostructure, extracted from the measured system modulus, was determined between two bounds set by the receding contact and the perfect bond interaction between a nanostructure and a substrate, respectively. The extracted modulus increases as the width-to-thickness ratio of a nanostructure increases from 1 to 2.
Regression Modeling Strategies

Regression models are frequently used to develop diagnostic, prognostic, and health resource utilization models in clinical, health services, outcomes, pharmacoeconomic, and epidemiologic research, and in a multitude of non-health-related areas. Regression models are also used to adjust for patient heterogeneity in randomized clinical trials, to obtain tests that are more powerful and valid than unadjusted treatment comparisons.
Glucagon: Its Enhancement of Atrioventricular Nodal Pacemaker Activity and Failure to Increase Ventricular Automaticity in Dogs

The effects of glucagon on atrioventricular nodal automaticity and ventricular automaticity were studied in anesthetized open-chest dogs. After the sinoatrial node was crushed, glucagon, 4 µg/kg, produced a marked and sustained increase in the rate of A-V nodal discharge (27.6 ± 10.1 vs. 117.4 ± 6.5 beats/min) that persisted for an average of 20 minutes. The effect of glucagon was not modified by previous administration of propranolol, 2 mg/kg. Repeated administrations of glucagon, 1 µg/kg every 15 min, for a period of 2 hours, sustained A-V nodal rhythm. The effects of glucagon on ventricular automaticity were studied in unanesthetized dogs 48 and 72 hours after surgical ligation of the anterior descending coronary artery and were compared to the effects of epinephrine. Unlike the catecholamine, glucagon did not enhance ventricular automaticity in the infarcted myocardium. The results suggest that glucagon might be of therapeutic value in the management of heart block and in cardiogenic shock after acute myocardial infarction. The inability to augment ventricular ectopic activity suggests that glucagon possesses an advantage over the catecholamines as an inotropic agent.