cssi/SciSciGPT-SciSciNet huggingface dataset:
Kinetic characterization of the ATPase cycle of the molecular chaperone Hsc66 from Escherichia coli.

Next Section Abstract Hsc66 from Escherichia coli is a constitutively expressed hsp70 class molecular chaperone whose activity is coupled to ATP binding and hydrolysis. To better understand the mechanism and regulation of Hsc66, we investigated the kinetics of ATP hydrolysis and the interactions of Hsc66 with nucleotides. Steady-state experiments revealed that Hsc66 has a low affinity for ATP (K m ATP = 12.7 μm) compared with other hsp70 chaperones. The kinetics of nucleotide binding were determined by analyzing changes in the Hsc66 absorbance spectrum using stopped-flow methods at 23 °C. ATP binding results in a rapid, biphasic increase of Hsc66 absorbance at 280 nm; this is interpreted as arising from a two-step process in which ATP binding (k a ATP = 4.2 × 104 m −1s−1, k d ATP= 1.1 s−1) is followed by a slow conformational change (k conf = 0.1 s−1). Under single turnover conditions, the ATP-induced transition decays exponentially with a rate (k decay = 0.0013 s−1) similar to that observed in both steady-state and single turnover ATP hydrolysis experiments (k hyd = 0.0014 s−1). ADP binding to Hsc66 results in a monophasic transition in the absence (k a ADP = 7 × 105 m −1 s−1,k d ADP = 60 s−1) and presence of physiological levels of inorganic phosphate (k a ADP(Pi)) = 0.28 × 105 m −1s−1,k d ADP(Pi)= 9.1 s−1). These results indicate that ATP hydrolysis is the rate-limiting step under steady-state conditions and is >103-fold slower than the rate of ADP/ATP exchange. Thus, in contrast to DnaK and eukaryotic forms of hsp70 that have been characterized to date, the R ⇔ T equilibrium balance for Hsc66 is shifted in favor of the low peptide affinity T state, and regulation of the reaction cycle is expected to occur at the ATP hydrolysis step rather than at nucleotide exchange.
Transforming growth factor β1 inhibits cytokine-induced CNS endothelial cell activation

Postcapillary endothelium at the sites of inflammation undergoes a series of changes collectively termed endothelial cell activation. Activated endothelium expresses immunologically relevant surface proteins that include MHC class II antigens (Ags) and adhesion proteins, as well as exhibits a number of functional changes. Endothelial activation has not been thoroughly studied in CNS endothelium. We have examined cytokine-mediated endothelial activation in isolated rat CNS microvessels. Freshly isolated rat CNS microvessels are viable in culture for at least 72 h. Untreated microvessels express no endothelial activation antigens, but do exhibit constitutive expression of the transferrin receptor (tfR). INFγ induces a dose-dependent increase in both MHC class II antigens and tfR measured by immunofluorescent staining and quantitated by laser cytometry. IFNγ-mediated endothelial cell activation could be inhibited with as little as 2 ng/mL TGF-β1, although 100% inhibition was seen with 10 ng/mL TGF-β1. Cytokinepreactivated endothelial expression of class II Ag and tfR could also be inhibited by TGF-β1. TGF-β1-treated microvessels become anergic to IFNγ stimulation. Results suggest that TGF-β1 may have a regulatory role in endothelial activation.
Vibrational-exciton couplings for the amide I, II, III, and A modes of peptides.

The couplings between all amide fundamentals and their overtones and combination vibrational states are calculated. Combined with the level energies reported previously (Hayashi, T.; Zhuang, W.; Mukamel, S. J. Phys. Chem. A 2005, 109, 9747), we obtain a complete effective vibrational Hamiltonian for the entire amide system. Couplings between neighboring peptide units are obtained using the anharmonic vibrational Hamiltonian of glycine dipeptide (GLDP) at the BPW91/6-31G(d,p) level. Electrostatic couplings between non-neighboring units are calculated by the fourth rank transition multipole coupling (TMC) expansion, including 1/R3 (dipole−dipole), 1/R4 (quadrupole−dipole), and 1/R5 (quadrupole−quadrupole and octapole−dipole) interactions. Exciton delocalization length and its variation with frequency in the various amide bands are calculated. The simulated infrared amide I and II absorptions and CD spectra of 24 residue α-helical motifs (SPE3) are in good agreement with experiment.
Planning of Directionally Drilled Wells in the Offshore Wilmington Field Using the Hand-Held Calculator

As of July 1982, 901 wells have been directionally drilled in the Long Beach Unit of the East Wilmington Field from 4 man-made islands and land based drilling sites. As more wells are added to each site the planning of new well courses has become more complex. The hand held calculator with Long Beach Unit developed programs has been an aid in laying out new wells which will avoid existing cased boreholes.
On the role of social interaction in social cognition: a mechanistic alternative to enactivism

Researchers in the enactivist tradition have recently argued that social interaction can constitute social cognition, rather than simply serve as the context for social cognition. They contend that a focus on social interaction corrects the overemphasis on mechanisms inside the individual in the explanation of social cognition. I critically assess enactivism’s claims about the explanatory role of social interaction in social cognition. After sketching the enactivist approach to cognition in general and social cognition in particular, I identify problems with an enactivist taxonomy of roles for social interaction in the explanation of social cognition (contextual, enabling, and constitutive). In particular, I show that this enactivist taxonomy does not clearly distinguish between enabling conditions and constitutive elements, which would make them in danger of committing the coupling-constitution fallacy found in some attempts to extend cognition. I explore resources enactivism has to more clearly demarcate constitutive parts of a cognitive system, but identify problems in applying them to some of the main cases of social cognition enactivists characterize as being constituted by social interaction. I offer the mechanistic approach to explanation as an alternative that captures much of what enactivists want to say about the relations between social and individual levels, but views social interactions from the perspective of embedded cognition rather than as being constitutive of social cognition.
Dynamic kerr effect measurements on photoreceptor disk membrane vesicles.

Abstract Dynamic Kerr effect measurements were performed with dilute aqueous suspensions of monodisperse spherical vesicles (~1μm diameter), isolated from the rod outer segment of bovine retina. A large birefringence, amounting to the specific Kerr constant of 10 −3 esu, can be observed. When a sufficiently long duration pulse (1 s) is applied, the decay of birefringence can be represented by a single exponential profile, yielding a relaxation time of 100 ± 20 ms in 1 mM imidazole buffer. This is consistent with the rotatory relaxation time of these spherical membrane vesicles. When a short duration is applied, the birefringence increases more steeply and the decay profile contains several components. The slowest (terminal) relaxation time is 86 ± 15 ms and is due to the same process as the one observed in the slow pulse case.
Regulation of Cdc42 expression and signaling is critical for promoting corneal epithelial wound healing.

PURPOSE Cdc42, a member of Rho GTPases (guanosine triphosphatases), participates in cytokine- and growth factor-controlled biological functions in mammalian tissues. Here, we examined Cdc42 role in corneal epithelial wound healing and the influence of hepatocyte, keratinocyte, and epidermal growth factor (HGF, KGF, and EGF)-mediated signaling on Cdc42. METHODS Epithelial wounds were created on the corneas of live rabbits by complete debridement and in rabbit corneal epithelial primary cultures through scratch injury. Cdc42 expression in cultures was suppressed using Cdc42 siRNA. Cdc42 activation was determined by pull-down assays with PAK-agarose beads. Cdc42 expression was analyzed by immunoblotting and immunofluorescence. Association of Cdc42 with cell-cycle proteins was identified by immunoprecipitation. RESULTS In rabbit corneas, significant increase in Cdc42 expression that occurred 2 to 4 days after the injury coincided with wound closure, and by 8 days the expression reached near basal levels. Silencing of Cdc42 expression in cultures caused inhibition of wound closure as a result of 60% to 75% decrease in epithelial migration and growth. HGF, KGF, and EGF increased Cdc2 expression, activation, and its phosphorylation on ser71. Inhibition of growth factor-mediated PI-3K signaling resulted in the downregulation of Cdc42 expression and its phosphorylation. Increased association of cell-cycle proteins p27(kip) and cyclin-dependent kinase 4 (CDK4) with Cdc42; and phosphorylated Cdc42 with plasma membrane leading edges was also observed in the presence of growth factors. CONCLUSIONS Cdc42 is an important regulator of corneal epithelial wound repair. To promote healing, Cdc42 may interact with receptor tyrosine kinase-activated signaling cascades that participate in cell migration and cell-cycle progression.
A Model of Damage and Healing Coupling Halite Thermo-mechanical Behavior to Microstructure Evolution

Creep processes in halite (salt rock) include glide, cross-slip, diffusion and dynamic recrystallization. Diffusive mass transfer (DMT) can result in crack rebonding, and mechanical stiffness recovery. Crack rebonding driven by DMT occurs within a few days at room temperature and low pressure. DMT is enhanced at higher temperatures, which could be beneficial for the sustainabilty of geological storage facilities in salt mines. On the one hand, visco-plastic laws relating creep microscopic processes to microstructure changes are empirical. On the other hand, theoretical models of damage and healing disconnect thermodynamic variables from their physical meaning. The proposed model enriches the framework of continuum damage mechanics with fabric descriptors. In order to infer the form of fabric tensors from microstructure observation, creep tests were carried out on granular salt under constant stress and humidity conditions. The evolution of net damage is governed by a diffusion equation, in which the characteristic time scales with the typical size of halite crystals, and the diffusion coefficient is a function of temperature. A stress path comprising a tensile loading, a compressive unloading, a creep–healing stage and a reloading was simulated. Macroscopic and microscopic model predictions highlight the increased efficiency of healing with time and temperature. The model presented in this paper is expected to improve the fundamental understanding of damage and healing in rocks at both macroscopic and microscopic levels, and the long-term assessment of geological storage facilities.
Enzymatic enhancement of the catalytic rate of sulfhydryl oxidase.

Abstract The rate of oxidation of glutathione by solubilized sulfhydryl oxidase was significantly enhanced in the presence of horseradish peroxidase (donor:hydrogen-peroxide oxidoreductase, EC 1.11.1.7). This enhancement was proportional to the amount of active peroxidase in the assay, but could not be attributed solely to the oxidation of glutathione catalyzed by the peroxidase. A change in the Soret region of the horseradish peroxidase spectrum was observed when both glutathione and peroxidase were present. Morever, addition of glutathione to a sulfhydryl oxidase/horseradish peroxidase mixture resulted in a rapid shift of the absorbance maximum from 403 nm to 417 nm. This shift indicates the oxidation of horseradish peroxidase. Spectra for three isozyme preparations of horseradish peroxidase, two acidic and one basic, all underwent this red-shift in the presence of sulfhydryl oxidase and glutathione. Cysteine and N -acetylcystein could replace glutathione. Addition of catalase had no effect on the oxidation of peroxidase, indicating that the peroxide involved in the reaction was not derived from that released into the bulk solution by sulfhydryl oxidase-catalyzed thiol oxidation. Further evidence for a direct transfer of the hydrogen peroxide moiety was obtained by addition of glutaraldehyde to a sulfhydryl oxidase/horseradish peroxidase/ N -acetylecysteine mixture. Size exclusion chromatography revealed the formation of a high-molecular-weight species with peroxidase activity, which was completely resolved from native horseradish peroxidase. Formation of this species was absolutely dependent on the presence of both the cysteine-containing substrate and sulfhydryl oxidase. The observed enhancement of sulfhydryl oxidase catalytic activity by the addition of horseradish peroxidase supports a bi uni uni ping-pong mechanism proposed previously for sulfhydryl oxidase.
Using Analogies to Improve the Teaching Performance of Preservice Teachers.

Prior research in both education and cognitive science has identified analogy making as a powerful tool for explanation as well as a fundamental mechanism for facilitating an individual's construction of knowledge. While a considerable body of research exists focusing on the role analogy plays in learning science concepts, relatively little is known about how instruction in the use of analogies might influence the teaching performance of preservice teachers. The primary objective of this study was to investigate the relationship between pedagogical analogy use and pedagogical reasoning ability in a sample of preservice elementary teachers (PTs), a group that has been identified for their particular difficulties in teaching science. The study utilized a treatment/contrast group design in which the treatment group was provided instruction that guided them in the generation of analogies to aid in the explanation phase of learning cycle lessons. A relationship between analogy use and positive indicants of teaching performance was observed and a case study of a low performing preservice teacher who drastically improved teaching performance using analogy-based pedagogy is presented. A notable effect on conceptual understanding of Newton's Third Law as a result of two brief analogy-based demonstration lessons was also observed. © 2007 Wiley Periodicals, Inc. J Res Sci Teach 44: 565–585, 2007.
Comparing Two Approaches for Assessing Observation Impact

Langland and Baker introduced an approach to assess the impact of observations on the forecasts. In that approach, a state-space aspect of the forecast is defined and a procedure is derived ultimately relating changes in the aspect with changes in the observing system. Some features of the state-space approach are to be noted: the typical choice of forecast aspect is rather subjective and leads to incomplete assessment of the observing system, it requires availability of a verification state that is in practice correlated with the forecast, and it involves the adjoint operator of the entire data assimilation system and is thus constrained by the validity of this operator. This article revisits the topic of observation impacts from the perspective of estimation theory. An observation-space metric is used to allow inferring observation impact on the forecasts without the limitations just mentioned. Using differences of observation-minus-forecast residuals obtained from consecutive forecasts leads to the following advantages: (i) it suggests a rather natural choice of forecast aspect that directly links to the data assimilation procedure, (ii) it avoids introducing undesirable correlations in the forecast aspect since verification is done against the observations, and (iii) it does not involve linearization and use of adjoints. The observation-space approach has the additional advantage of being nearly cost free and very simple to implement. In its simplest form it reduces to evaluating the statistics of observationminus- background and observation-minus-analysis residuals with traditional methods. Illustrations comparing the approaches are given using the NASA Goddard Earth Observing System.
Method for Evaluation of Thermochemical and Hybrid Water-Splitting Cycles

This paper presents a methodology for the preliminary evaluation of thermochemical and hybrid water-splitting cycles based on efficiency. Because the method does not incorporate sufficient flowsheet details, the efficiencies are upper bounds of the real efficiencies. Nonetheless, they provide sufficient information to warrant comparison with existing well-studied cycles, supporting the decision to disregard them when the bound is too low or continuing their study. In addition, we add features not present in previous works: equilibrium conversions as well as excess reactants are considered. The degrees of freedom of each cycle (temperatures, pressures, and excess reactants) were also considered, and these values were varied to optimize the cycle efficiency. Ten cycles are used to illustrate the method.
Regulation of particulate guanylatecy cylase by Escherichia coli heat-stable enterotoxin: Receptor binding and enzyme kinetics

Abstract 1. 1. Escherichia coli heat-stable enterotoxin (ST) induces a secretory diarrhea by binding to receptors on brush borders of intestinal villus cells, activating particulate guanylate cyclase and increasing intracellular concentrations of guanosine 3',5'-cyclic monophosphate (cyclic GMP). 2. 2. However, little is known concerning coupling of receptor-ligand interaction to enzyme activation. 3. 3. This study compares the kinetics of toxin-receptor binding and enzyme activation to better understand this transmembrane signal cascade. 4. 4. Toxin receptor binding was linear and saturable with 50% of maximum displacement off[ 125 I]ST by unlabeled toxin observed at 1.1 × 10 −7 M. ST increased the maximum velocity ( V max ) of guanylate cyclase with magnesium or manganese as the cation substrate without altering the affinity of the enzyme for its substrate or its positive cooperativity. 5. 5. The concentration of toxin yielding half-maximum stimulation of guanylate cyclase was 1.2 × 10 −6 M, 10-fold higher than the affinity of the ligand for its receptor. 6. 6. These data are consistent with the suggestion that ST-receptor interaction is coupled to activation of particulate guanylate cyclase. 7. 7. However, the discrepancy between the affinity of ST for its receptor and its efficacy in activating the enzyme suggests that this coupling is complex. 8. 8. Possible mechanisms underlying this coupling are discussed.
Environmental effects on antifreeze levels in larvae of the darkling beetle, Meracantha contracta

Acclimation of Meracantha contracta larvae collected in late summer to low temperatures, short photoperiods or low relative humidities induces production of a macromolecular antifreeze which functions to depress the freezing and supercooling points of the larvae. Overwintering larvae must be exposed to a combination of high temperature and long photoperiod before the antifreeze is lost.
Utility of AIRS retrievals for climate studies

Satellites provide an ideal platform to study the Earth-atmosphere system on practically all spatial and temporal scales. Thus, one may expect that their rapidly growing datasets could provide crucial insights not only for short-term weather processes/predictions but into ongoing and future climate change processes as well. Though Earth-observing satellites have been around for decades, extracting climatically reliable information from their widely varying datasets faces rather formidable challenges. AIRS/AMSU is a state of the art infrared/microwave sounding system that was launched on the EOS Aqua platform on May 4, 2002, and has been providing operational quality measurements since September 2002. In addition to temperature and atmospheric constituent profiles, outgoing longwave radiation and basic cloud parameters are also derived from the AIRS/AMSU observations. However, so far the AIRS products have not been rigorously evaluated and/or validated on a large scale. Here we present preliminary assessments of monthly and 8-day mean AIRS "Version 4.0" retrieved products (available to the public through the DAAC at NASA/GSFC) to assess their utility for climate studies. First we present "consistency checks" by evaluating the time series of means, and "anomalies" (relative to the first 4 full years' worth of AIRS "climate statistics") of several climatically important retrieved parameters. Finally, we also present preliminary results regarding interrelationships of some of these geophysical variables, to assess to what extent they are consistent with the known physics of climate variability/change. In particular, we find at least one observed relationship which contradicts current general circulation climate (GCM) model results: the global water vapor climate feedback which is expected to be strongly positive is deduced to be slightly negative (shades of the "Lindzen effect"?). Though the current AIRS climatology covers only -4.5 years, it will hopefully extend much further into the future.
The Frizzled-1/β2-adrenergic receptor chimera: pharmacological properties of a unique G protein-linked receptor

The frizzled gene family of Wnt receptors encodes proteins that have a seven-transmembrane-spanning motif characteristic of G-protein-coupled receptors. Using a chimeric receptor composed of the exofacial and the transmembrane, ligand-binding domain of the β2-adrenergic receptor (β2AR) fused with the corresponding cytoplasmic domains of the rat Frizzled-1 receptor (Rfz1), we created a unique chimera between distant members of the superfamily of G protein-coupled receptors. Herein, we describe the pharmacological properties of the chimera, which represents a receptor in which the exofacial and cytoplasmic domains are minimized in length. This unique chimera retains much of the pharmacological character of the native β2AR, whereas the coupling can be ascribed to Rfz1 domains which operate via Gαq and not Gαs. The Rfz1 chimera demonstrates a robust agonist (isoproterenol)-induced sequestration. Since the Rfz1 cytoplasmic domains possess canonical sites for several protein kinases, we were able to investigate the effects of kinase inhibitors on Rfz1 chimera sequestration. Only the protein kinase A inhibitor KT5720, but not inhibitors of protein kinase C, calcium/calmodulin-sensitive kinase-2, casein kinase-2, and Src, inhibited agonist-induced sequestration. Expression of a dominant-negative form of β-arrestin blocked sequestration of the β2AR, but only reduced modestly that of the Rfz1 chimera. These data demonstrate that the Frizzled-1 chimera displays cardinal features of a G protein-coupled receptor, including agonist-induced sequestration, but appears to do so largely even in the presence of dominant-negative β-arrestins.
Physical and mental health-related quality of life among older people with schizophrenia

Objective Since the time of Kraeplin, schizophrenia has been thought of as a disorder with progressive deterioration in functioning. An important aspect of functioning is both physical and mental health-related quality of life (HRQoL). The objective of this study was to examine the relationship of age to both mental and physical aspects of HRQoL in individuals with schizophrenia as compared to normal comparison subjects (NCs).
4-TW, 10-Hz or 6-W, 2-kHz pulses from a versatile, compact CPA laser

Summary form only given. High intensity physics and time resolved chemistry benefit from powerful university-scale laser systems. We have developed an efficient, two-stage laser that can produce high average power kilohertz repetition rate pulses, such as needed by high harmonic generation, or multi-terawatt peak power pluses, for applications like pulsed X-ray diffraction. Stage 2 is a 6-mJ regenerative amplifier that can operate at repetition rates from 1-kHz. The regenerative amplifier has a 30% pump energy conversion efficiency and requires only one pump laser (Quantronix 527DQ). Stage 2 of the laser system is a 0.26 J, 4-pass amplifier designed in collaboration with ALTOS/ESKMA.
Imported fenproporex-based diet pills from Brazil: a report of two cases.

Banned amphetamine-based anorectics are illicitly imported into the United States (US), but little is known regarding the harm these diet pills pose to US residents. A 26-year-old woman using imported diet pills presented with a two-year history of intermittent chest pains, palpitations, headaches and insomnia. Urine toxicology screen detected amphetamines and benzodiazepines. Fenproporex and chlordiazepoxide were detected in her pills. Her symptoms resolved after she stopped using diet pills. A 38-year-old man using imported diet pills presented after his occupational urine screen was significantly positive for amphetamine. Fenproporex and fluoxetine were detected in his pills. These cases illustrate the potential harm from imported prescription diet pills that combine fenproporex with benzodiazepines, antidepressants, diuretics, laxatives and other substances. Increasing physicians’ awareness of imported diet pill use may improve care of patients suffering from the pills’ many adverse effects.
Solution of the Chandler-Gibson equations for a three-body test problem.

The Chandler-Gibson (CG) {ital N}-body equations are tested by considering the problem of three nonrelativistic particles moving on a line and interacting through attractive delta-function potentials. In particular, the input Born and overlap matrix-valued functions are evaluated analytically, and the CG equations are solved using a {ital B}-spline collocation method. The computed scattering matrix elements are within 0.5% of the known exact solutions, and the corresponding scattering probabilities are within 0.001% of the exact probabilities, both below and above the 3-body breakup threshold. These results establish that the CG method is practical, as well as theoretically correct, and may be a valuable approach for solving certain more complicated {ital N}-body scattering problems.
Theory of a Class of Locally Convex Vector Lattices Which Include the Lebesgue Spaces

Abstract In this paper is presented the theory of a class of locally convex lattices (L-lattices) of real functions which generalize the classical Lebesgue spaces. The monotone and dominated convergence theorems for convergence almost everywhere and sequential and order completeness of such lattices are established. These results are obtained through characterization of linear lattices of functions closed under pointwise or dominated convergence everywhere and closed under Stone's operation f → f[unk]1. Such lattices are characterized in terms of measurability with respect to sigma or delta rings. Application to the theory of Lebesgue integrals is given, permitting one to obtain the classical theory of the integral and of the Lp spaces directly from the axioms of the integral. Representations of L-lattices in terms of Lebesgue integrals and extensions of L-lattices through addition of null functions are given.
The price of seizure control: Dynorphins in interictal and postictal psychosis

Postictal and interictal psychoses are relatively common complicating factors in the clinical course of epilepsy, yet their neurobiological substrates are poorly understood. Recent evidence shows that kappa opioid receptor (KOR) activation elicits anticonvulsant and psychotomimetic effects. In view of this background, here we introduce the hypothesis that epilepsy-related psychoses may partially result from excessive hippocampal dynorphin release and kappa opioid receptor overstimulation aimed at seizure control.
An Adaptive Nonlinear Least-Squares Algorithm

NL2SOL is a modular program for solving nonlinear least-squares problems that incorporate a number of novel features. It maintains a secant approximation S to the second-order part of the least-squares Hessian and adaptively decides when to use this approximation. S is "sized" before updating, something which is similar to Oren-Luenberger scaling. The step choice algorithm is based on minimizing a local quadratic model of the sum of squares function constrained to an elliptical trust region centered at the current approximate minimizer. This is accomplished using ideas discussed by More'', together with a special module for assessing the quality of the step thus computed. These and other ideas behind NL2SOL are discussed and its evolution and current implemetation are also described briefly.
ARARMA models for time series analysis and forecasting

Methods of time series forecasting are proposed which can be applied automatically. However, they are not rote formulae, since they are based on a flexible philosophy which can provide several models for consideration. In addition it provides diverse diagnostics for qualitatively and quantitatively estimating how well one can forecast a series. The models considered are called ARARMA models (or ARAR models) because the model fitted to a long memory time series (t) is based on sophisticated time series analysis of AR (or ARMA) schemes (short memory models) fitted to residuals Y(t) obtained by parsimonious‘best lag’non-stationary autoregression. Both long range and short range forecasts are provided by an ARARMA model Section 1 explains the philosophy of our approach to time series model identification. Sections 2 and 3 attempt to relate our approach to some standard approaches to forecasting; exponential smoothing methods are developed from the point of view of prediction theory (section 2) and extended (section 3). ARARMA models are introduced (section 4). Methods of ARARMA model fitting are outlined (sections 5,6). Since‘the proof of the pudding is in the eating’, the methods proposed are illustrated (section 7) using the classic example of international airline passengers.
Albuminuria Associates With Calcified Atherosclerotic Plaque in African Americans With Diabetes

Relative to individuals with European ancestry, presence and severity of calcified atherosclerotic plaque (CP) are markedly lower in individuals with African ancestry (1,2). Factors potentially contributing to the ethnic variation in susceptibility to atherosclerosis include different relationships between CP and serum 25 hydroxyvitamin D concentrations and pericardial adipose tissue volumes in African Americans (AAs) relative to European Americans (EAs) (3,4). In addition, significant positive associations have been observed between CP and albuminuria in EAs with type 2 diabetes (5) but not AAs (419 subjects from 297 African American Diabetes Heart Study [AA-DHS] families) (6). Therefore, it remains unclear whether ethnic differences exist in the effect of albuminuria on risk for development and progression of CP. To improve power for detecting associations between …
Fluid Mechanics of Distillation Trays (II): Prediction of Flow Fields on Some Practically Important Sieve Trays

Abstract Separation processes account for 6% of the annual US energy expenditure, 50% of which is consumed by distillation alone. Therefore, it is not too surprising that distillation, the work horse of the chemical process industry, is under attack by emerging technologies based on membranes and adsorption, whose proponents claim enormous potential savings in energy expenditure. Moreover, the massive scale of use plus the energy intensiveness implies that even small improvements in the efficiency of distillation processes can result in large gains in energy savings. Such improvements can come from developing a fundamental understanding of the fluid mechanics of tray columns, which has heretofore been lacking and is the subject of this paper. The flow on a distillation tray is governed by the equations of mass and momentum conservation in three-dimensions. These equations are reduced here to a set of two-dimensional equations by averaging them across the depth of the fluid film flowing across the tray. Th...
Kinetic studies of 18O exchange of inorganic phosphate using mass spectral measurements on the tris-(trimethylsilyl) derivative.

Abstract The kinetics of 16 O exchange into 18 O-enriched inorganic phosphate catalyzed by Escherichia coli alkaline phosphatase have been followed by generating the tris-(trimethylsilyl) derivative of the phosphate samples and subjecting this volatile derivative to mass spectral analysis. The series of sequential reactions involved in the 18 O exchange have been analyzed mathematically, and theoretical plots of the time courses of the exchange processes have been generated assuming various fractional initial 18 O distributions. Using this mathematical model, a rate constant was obtained which gives the best fit to the experimental kinetic data. This approach is much less time-consuming than the traditional method of thermal conversion of the 18 O-enriched phosphate samples to carbon dioxide using vacuum line techniques. Morcover, the data analysis, alboit more complex than that using the traditional method, enables five independent determinations of the exchange rate to be made from each phosphate sample. Although this new approach requires much more highly 18 O-enriched water than does the traditional method, such highly enriched water is now readily available at reasonable cost.
External Forced Convection Enhancement Using a Corona Discharge

An ionic wind is formed when air ions generated by a corona discharge are accelerated by an electric field and exchange momentum with neutral air molecules, causing air flow. Because ionic winds can generate flow with no moving parts, they offer an attractive method for enhancing the heat transfer from a surface that would otherwise only be cooled by natural convection and/or radiation. In the presence of an external, flat plate flow, ionic winds distort the boundary layer such that local heat transfer is enhanced at the wall, and recent work has suggested that integrating such devices can be useful for cooling electronic components locally. In this work, corona discharges are generated between a steel wire and copper tape electrode pair on a flat plate, perpendicular to the bulk flow direction such that the discharge is in the direction of the bulk flow. The corona discharge current is characterized, and a corona glow and spark discharge are visualized. Experimental studies of the heat transfer from a heated flat plate are conducted using an infrared camera which indicated both upstream and downstream cooling along the entire length of the wire. Heat transfer coefficients are increased by more than 200% above those obtained from bulk flow alone and are correlated to the fourth root of the corona current. Preliminary parametric studies demonstrate the influence of the electrode-pair configuration on the cooling enhancement and suggest improved geometric designs.Copyright © 2007 by ASME
Purification of bovine heart glycogen synthase.

Abstract Glycogen synthase was purified to apparent homogeneity from bovine heart muscle by a procedure involving precipitation of the enzyme in the presence of added glycogen by polyethylene glycol, chromatography on DEAE-Sephacel, and high-speed centrifugation through a sucrose-containing buffer. The enzyme was maintained in the presence of glycogen during the isolation procedure. Glycogen synthase I and D preparations were obtained having specific activities of 21–25 and 30–35 units/mg protein at pH 7.8 and 30°C and having activity ratios of 0.5–0.6 and 0.05–0.10, respectively, when assayed in the absence and in the presence of glucose 6-P.
Nuclear magnetic resonance of the base-pairing structure of the native and denatured conformers of Escherichia coli transfer RNATrp

The native and denatured forms of transfer RNATrp from Escherichia coli have been studied by high-resolution (300 MHz) proton nuclear magnetic resonance spectroscopy. The low-field nuclear magnetic resonance spectrum indicates that there are 22 ± 2 base-pairs present in the native form, and the observed resonance positions can be accounted for in terms of 19 base-pairs from the cloverleaf secondary structure, one protected U, and two tertiary structure base-pairs including A14-s4U8. The denatured conformer contains one or two less base-pairs than the native conformer, and the low-field spectrum of the denatured conformer can be accounted for in terms of a model which retains the amino acid acceptor stem, T ΨC stem, and the anticodon stem of the cloverleaf model, but which pairs some bases of the dihydrouridine stem with bases from the minor loop. The proposed model is consistent with the ease of interconversion of the native and denatured conformers, the pattern of kethoxalation of the native and denatured conformera, and the retention of a tertiary structure A14-s4U8 base-pair in the denatured conformer. Alternative models of the denatured form are considered, but they do not adequately explain the observed nuclear magnetic resonance spectrum. The binding of chloroquine to the native conformer has also been studied. A comparison of the binding of ethidium bromide and chloroquine to E. coli tRNAGlu indicates that the two drugs have very similar binding properties and this suggests a possible mechanism for the chloroquine-induced renaturation of tRNATrp.
Microcanonical quantum field theory

Abstract Euclidean quantum field theory is equivalent to the equilibrium statistical mechanics of classical fields in 4 + 1 dimensions at temperature ħ. It is well known in statistical mechanics that the theory of systems at fixed temperature is embedded within the more general and fundamental theory of systems at fixed energy. We therefore develop, in precise analogy, a fixed action (microcanonical) formulation of quantum field theory. For the case of ordinary renormalizable field theories, we show (with one exception) that the microcanonical is entirely equivalent to the canonical formulation. That is, for some particular fixed value of the total action, the Green's functions of the microcanonical theory are equal, in the bulk limit, to those of the canonical theory. The microcanonical perturbation expansion is developed in some detail for λφ 4 . The particular value of the action for which the two formulations are equivalent can be calculated to all orders in perturbation theory. We prove, using Lehmann's Theorem, that this value is one-half Planck unit per degree of freedom, if fermionic degrees of freedom are counted negatively. This is the 4 + 1 dimensional analog of the equipartition theorem. The one exception to this is supersymmetric theories. A microcanonical formulation exists if and only if supersymmetry is broken. In statistical mechanics and in field theory there are systems for which the canonical description is pathological, but the microcanonical is not. An example of such a field theory is found in one dimension. A semiclassical expansion of the microcanonical theory is well defined, while an expansion of the canonical theory is hopelessly divergent. Finally, it is argued that a microcanonical formulation of quantum gravity may similarly be less pathological than the usual canonical formulation. The relation between the total action and the temperature ħ is calculated to all orders using the gravitational Schwinger-Dyson equations.
Effects of parathyroid hormone (PTH)-related protein and PTH on osteoclasts and osteoclast precursors in vivo

Increased production of PTH-related protein (PTHrP) and PTH is frequently responsible for hypercalcemia and its associated morbidity. However, it is unclear whether these peptides produce identical effects on cells in the osteoclast lineage in vivo. To examine the effects of continuous in vivo exposure to these factors on both the osteoclast precursors and mature osteoclasts, we inoculated Chinese hamster ovarian cells expressing PTH-(1-84), PTHrP-(1-141), or nontransfected Chinese hamster ovarian cells into nude mice. The effects of these tumors on blood ionized calcium, plasma PTH and PTHrP concentrations, and osteoclast formation were then determined. PTH and PTHrP tumor-bearing mice became hypercalcemic (1.90 +/- 0.04 and 1.97 +/- 0.16 mmol/liter, respectively) compared with control mice (1.29 +/- 0.015 mmol/liter). After 4 days of hypercalcemia, mice were killed, and bone marrow cells were harvested to examine cells at three discrete stages of osteoclast development: multipotent osteoclast precursors, the granulocyte/macrophage colony-forming unit; more committed marrow mononuclear osteoclast precursors; and mature osteoclasts. Neither PTH nor PTHrP had an effect on granulocyte/macrophage colony-forming unit, but similarly increased the number of more committed mononuclear osteoclast progenitors as well as mature osteoclasts in the calvaria. No differences were detected between the effects of PTH and PTHrP on cells in the osteoclast lineage in vivo. Thus, PTH and PTHrP appear to affect only more differentiated cells in the osteoclast lineage, and the differences in osteoclastic bone resorption between primary hyperparathyroidism and humoral hypercalcemia of malignancy are probably due to mechanisms other than effects on osteoclast precursor cells in vivo.
Vortex-induced vibrations of an elastically mounted sphere with three degrees of freedom at Re = 300: hysteresis and vortex shedding modes

Fluid–structure interaction (FSI) simulations are carried out to investigate vortex-induced vibrations of a sphere, mounted on elastic supports in all three spatial directions. The reduced velocity () is systematically varied in the range , while the Reynolds number and reduced mass are held fixed at and , respectively. In the lock-in regime, two distinct branches are observed in the response curve, each corresponding to a distinct type of vortex shedding, namely, hairpin and spiral vortices. While shedding of hairpin vortices has been observed in several previous investigations of stationary and vibrating spheres, the shedding of intertwined, longitudinal spiral vortices in the wake of a vibrating sphere is reported herein for the first time. When the wake is in the hairpin shedding mode, the sphere moves along a linear path in the transverse plane, while when spiral vortices are shed, the sphere vibrates along a circular orbit. In the spiral mode branch, the simulations reveal hysteresis in the response amplitude at the beginning of the lock-in regime. Lower-amplitude vibrations are found as the sphere sheds hairpin vortices for increasing up until the beginning of the synchronization regime. On the other hand, higher-amplitude oscillations persist for the spiral mode as is decreased from the point of the start of the synchronization. The hairpin mode is found to be unstable for the value of reduced velocity where the spiral and hairpin solution branches merge together. When this point is approached along the hairpin solution branch, the sphere naturally transitions from shedding hairpin vortices and moving along a linear path to shedding spiral vortices and moving along a circular path in the transverse plane. The spiral mode was not observed in the work of Horowitz & Williamson (J. Fluid Mech., vol. 651, 2010, pp. 251–294), who studied experimentally the vibration modes of a freely rising or falling sphere and only reported zigzag vibrations. Our results suggest that this apparent discrepancy between experiments and simulations should be attributed to the fact that, for the range of governing parameters considered in the simulations, the elastic supports act to suppress streamwise vibrations, thus subjecting the sphere to a nearly axisymmetric elasticity constraint and enabling it to vibrate transversely along a circular path.
Collateral circulation in coronary artery disease.

Abstract The coronary arteriograms and left ventriculograms of 202 consecutive patients were reviewed. All had at least 75% diameter reduction of 1 or more major coronary arteries. In 127 patients (63%), at least 1 major branch was totally occluded. Collateral circulation was seen in 125 of these 127 patients (190 of 102 totally occluded arteries). Of the 75 patients without total occlusion, only 2 with 99% (or near-total) occlusion had demonstrable collateral circulation (2 of 208 arteries). In no patient with 75 to 98% diameter narrowing was collateral circulation demonstrated (0 of 164 arteries). An analysis was made of the relation between left ventricular (LV) segmental wall motion and the quality of collateral circulation in 190 totally occluded arteries among 125 patients. Of 126 arteries with good collateral circulation, LV contraction was normal in 21%, hypokinetic in 48% and akinetic/dyskinetic in 29%. Of 64 arteries with poor collateral circulation, LV contraction was normal in 23%, hypokinetic in 55% and akinetic/dyskinetic in 20%. There was no statistically significant difference between the effect of good or poor collateral circulation on LV function. These data indicate that collateral circulation cannot be seen angiographically unless there is total or near-total occlusion, and that the presence of collateral circulation does not correlate with LV wall motion abnormalties, i.e., akinetic area, despite good collateral flow or normal wall motion despite absent or poor collateral flow.
The role of three-dimensional shapes in the break-up of charged drops

The nonlinear dynamics of nonaxisymmetric inviscid charged conducting drops near the Rayleigh charge limit (R = 4) is investigated analytically. It is shown that only axisymmetric spheroid drops bifurcate from the sphere family when the charge is increased, that oblate spheroids at R greater than 4 are unstable to nonaxisymmetric disturbances governing drop breakup, and that prolate spheroids at R less than 4 are unstable only to axisymmetric disturbances tending to increase the length of the drop along its symmetry axis. The effects of external electric fields and rigid-body rotation are also analyzed, and the solutions for the amplitude equations at R just less than 4 (equivalent to the dynamical equations of the Henon-Heiles Hamiltonian) are explored.
Library involvement in the implementation of a course management system.

Abstract Course management system software has much to offer the faculty and students in universities that adopt this technology. Libraries have used this technology to provide links to library resources, but they can also have a role in implementing the adoption of the course management software. The Penn State College of Medicine successfully implemented the ANGEL course management system under the guidance of a medical librarian. Tasks specific to the librarian included communication and promotion of ANGEL, in addition to providing training and technical support
Development of a Cytomic Force Transducer for Experimental Mechanobiology

In this work electrostatic actuation in ionic liquid environments was achieved through a unique atmospheric pressure packaging scheme in conjunction with Trichloro(1H, 1H, 2H, 2H-Perfluorooctyl)Silane surface modification. This technique avoids common problems of electrolysis, charge blocking, and current leakage without the need for any drive signal considerations. When combined with cellular self-assembly onto sacrificial polymers, this breakthrough opens the possibility of creating a cytomic force transduction system through which mechanobiological experiments can be conducted on a multitude of cell phenotypes in vitro. Testing of the device in liquid demonstrated actuation with as little as 15V and continuous operation in liquid was successful for over two weeks.
Assessing culture via the Internet: methods and techniques for psychological research.

This study examines the acculturation experiences of Arabic immigrants and assesses the utility of the Internet as a data collection tool. Based on in-depth pilot interview data from 10 male Arabic immigrants and items selected from pre-existing measures, the Male Arabic Ethnic Identity Measure (MAEIM) was developed. Male Arab immigrants (115 males) were solicited through traditional methods in addition to the Internet. Satisfactory reliability and validity were reported for the MAEIM. No significant differences emerged between the Internet and Midwestern samples. The Internet proved to be an effective method for soliciting a relatively large, geographically dispersed sample of Arabic immigrants. The use of the Internet as a research tool is examined in the context of anonymity, networking, low-cost, perceived interactive control, methodological rigor, and external validity. The Internet was an effective vehicle for addressing concerns raised by prospective participants. It is suggested that the Internet ...