cssi/SciSciGPT-SciSciNet huggingface dataset:
Solute and macromolecule diffusion in cellular aqueous compartments

Diffusion of solutes and macromolecules in aqueous cellular compartments is required for numerous cellular processes including metabolism, second messenger signaling and protein-protein interactions. The view of the cell interior has evolved from that of a viscous gel to that of a watery but crowded compartment. Recent measurements of fluorescent probe diffusion using photobleaching, correlation microscopy and time-resolved anisotropy methods, have indicated unexpectedly high mobilities of small solutes and macromolecules. This review evaluates experimental evidence defining the rates and barriers for molecular diffusion in cells. Possible implications of regulated molecular diffusion as a rate-limiting step in cell metabolism, and with respect to the delivery of therapeutic agents, are discussed.
Thermodynamic properties of ErFe2 AND DyFe2 hydrides

Abstract Hydrogen desorption isotherms were measured for ErFe 2 hydrides at 0, 20,40,60 and 80 °C and for DyFe 2 hydrides at 0 and 80 °C. Isopleths were measured from 0 to 95 °C for ErFe 2 H 0.60 , DyFe 2 H 0.61 and DyFe 2 H 3.1 . These data were used to calculate heats and entropies of absorption and formation. The heats of formation are much less negative than those obtained using the theory of Miedema, Buschow and van Mal. The entropies of the ErFe 2 hydrides exceed the entropy of ErFe 2 by much less than the calculated configurational entropy, except at the highest temperature.
Comparative lead emissions from conventional and jacketed ammunition

Because of the adverse health effects associated with excessive exposure to lead in firing ranges, attempts have been made to develop ammunition which could prevent such undesirable exposure. This study provides evidence that it is possible to reduce lead exposure significantly at the source of emission with the use of copper and nylon jacketed bullets.
Chemical Equations for Multireaction Systems

Algebraic equations were derived for plotting theoretical titration curves involving argentometric titration of binary halide mixtures. These generic equations are applied to three cases of binary halide mixtures in spreadsheet programs. The results are presented graphically as plots of half-cell potential versus volume of the titrant. This approach may serve as a more effective and logical method of showing students how to simulate a complex system involving multiple equilibria.
The ins and outs of viral RNA polymerase translocation.

Central to the replication of RNA viruses is the RNA-dependent RNA polymerase (RdRp) [1], an important antiviral drug target [2–4]. RdRps belong to a large superfamily of template-directed nucleic acid polymerases, including DNA polymerases and reverse transcriptases [1]. These polymerases have a similar structural fold, which has been described as a “cupped right hand” with fingers, thumb and palm subdomains [5] (Fig. 1), and a similar chemical mechanism, involving at least two metal ions [6]. Polymerase function can be divided into three phases, including nucleotide selection, phosphodiester bond formation and translocation to the next templating nucleobase to prepare for the next round of nucleotide addition. Structural biology has provided tremendous insight into the structural changes that accompany each stage of catalysis for multiple classes of polymerases [7–10]. Least understood is how conformational changes in the polymerases may couple to translocation. In A-family DNA polymerases, a partial opening of the active site involving the temporary displacement of the “O-helix” and other regions in the fingers subdomain is likely important for movement along the DNA [11– 15]. Such a mechanism is unlikely to aid translocation in RdRps; these polymerases contain an extension of the fingers through the “fingertips” that interacts with the thumb domain, likely precluding a similar “opening” of the active site [16] (Fig. 1). In this issue, Sholders and Peersen have provided tantalizing insight into an alternative mechanism for translocation in RdRps, involving a palm structural motif known as “motif-B” [17]. Steric clashes between the motif-B loop and the template RNA may promote movement along the RNA to the next catalytic register. These findings are especially intriguing considering that the motif-B loop is involved in multiple stages of RdRp catalysis and
Changes in dryness/wetness in China during the last 529 years

Historical written records of weather conditions that affect agriculture and living conditions in China can serve as a proxy for instrumental observations of the relative wetness and dryness, or precipitation amounts, for periods of time dating back to at least AD 1470. The dryness/wetness index (DW) data at 100 selected sites and at a subset of 25 sites with entirely continuous data indicate that during the growing season the number of sites with dryness increased rapidly in the 20th century, in contrast to a gradual increase and levelling off of wetness since the 18th century. Dry conditions existed mostly in northeastern China in the 16th and 17th centuries. In the 20th century, dryness prevailed in most areas in China, and the chance of occurrence at each site increased. Wet conditions have expanded from east coastal areas to inland since the 19th century. As a result of increased dryness and wetness, the number of sites experiencing normal precipitation conditions has dropped dramatically. The number of sites with extreme dryness/wetness has also increased during the 20th century, and the spatial distribution of the sites with a large chance of extreme dryness/wetness has also changed. The frequent occurrences in dryness/wetness as well as in extremes in the 20th century seem indicative of an abnormality in climate on a large scale. Spectral analyses of the DW data has revealed that cycles in dryness/wetness and their extremes have existed with periods on relatively short time scales as well as on the long time scales. The possible existence of a century-scale cycle suggests that caution should be used in relating variations in rainfall conditions to global warming. Copyright © 2000 Royal Meteorological Society
Anomalías físicas menores y vulnerabilidad en jóvenes con un síndrome prodrómico

Resumen Dado que tanto el cerebro como las caracteristicas craneofaciales/de extremidades tienen su origen en la misma capa germinal durante la fase inicial de la gestacion, la presencia posnatal de anomalias fisicas menores (AFM) que afectan a estas caracteristicas fisicas puede ser indicativa de la existencia de defectos de la migracion neural prenatal y, por consiguiente, de anomalias cerebrales en los individuos con psicosis. Sin embargo, hasta la fecha no se sabe que sintomas y caracteristicas de AFM pueden estar asociados, y de que modo pueden reflejar esos marcadores la vulnerabilidad para desarrollar una psicosis en los adolescentes de alto riesgo. Esta informacion es especialmente crucial para comprender la susceptibilidad e informar las conceptualizaciones etiologicas, como el modelo de diatesis-estres neural. En este estudio, se evaluo en 50 adolescentes con un sindrome prodromico la presencia de AFM, el cortisol salivar, la funcion de memoria auditiva y visual, y los sintomas atenuados positivos, negativos y de desorganizacion. Los resultados indicaron que los participantes que presentaban unas AFM elevadas (n = 25) se diferenciaban por un cortisol elevado, deficit de la memoria visual inmediata y tardia, y niveles mas altos de sintomas prodromicos de desorganizacion, en comparacion con los participantes en los que habia una menor incidencia de AFM. Esto fue respaldado por los analisis de correlacion adicionales en los que se examino a la totalidad de la muestra. Estas observaciones aportan un respaldo preliminar a la teoria de que las AFM pueden reflejar la vulnerabilidad del sistema del hipocampo en los pacientes prodromicos.
An analytical solution for percutaneous drug absorption: application and removal of the vehicle

The methods of Laplace transform were used to solve a mathematical model developed for percutaneous drug absorption. This model includes application and removal of the vehicle from the skin. A system of two linear partial differential equations was solved for the application period. The concentration of the medicinal agent in the skin at the end of the application period was used as the initial condition to determine the distribution of the drug in the skin following instantaneous removal of the vehicle. The influences of the diffusion and partition coefficients, clearance factor and vehicle layer thickness on the amount of drug in the vehicle and the skin were discussed.
Experimental observations of isolated surface steady-state branches

Abstract In this paper we report infrared spectroscopic observations of isolated surface steady-state branches during CO oxidation over Pt γ-Al 2 O 3 catalysts. These are branches that cannot be reached by continuous smooth changes of the experimentally controlled variables, but only through global perturbations of the catalytic reaction system.
Metaphors we teach by

In this paper we present an initial study of how metaphors are used by university-level Computer Science instructors. The goal of this research is to gain a better understanding of the role that metaphors play in Computer Science education, to catalog the kinds of metaphors that are used, and to assess their effectiveness in supporting learning. We interviewed 10 educators in Computer Science about the metaphors they have used in the classroom, with a focus on introductory "CS1" programming courses. We analyze these interviews with an existing theory of metaphors, which provides a framework for describing their structure and features. The theory predicts that most metaphors have limitations, and eventually fall apart. Therefore, we also asked educators to assess how far they could push their metaphors with and to describe what happens at the breaking point. Our preliminary findings provide a foundation to inform and guide more in-depth analyses in the future.
Effect of non-aqueous solvents on the chemisorption and orientation of aromatic compounds at smooth polycrystalline platinum electrodes: naphthohydroquinone and tetrahydroxybiphenyl in water + acetonitrile solutions

Abstract The chemisorption of 1,4-naphthohydroquinone (NHQ) and 2,2′,5,5′,-tetrahydroxybiphenyl (THBP) at smooth polycrystalline Pt electrodes has been studied in aqueous solutions containing preselected amounts of acetonitrile (ACN), a widely-used non-aqueous solvent. Chemisorption measurements were made with thin-layer electrodes. The presence of ACN in solution led to a mixed organic layer whose composition showed a dependence on the ACN-to-aromatic concentration ratio. The comparatively weak adsorbability of ACN was manifested by the fact that, at an ACN-to-aromatic ratio of 100:1, the amount of THBP chemisorbed was still about 60% of the value measured in the absence of ACN. THBP chemisorption was still present at much higher ACN/THBP ratios, but the adsorption data for reversibly-electroactive THBP indicated that under these severe conditions THBP was chemisorbed only in the edgewise orientation. That is, the adsorbability of ACN was such that, when present at high bulk concentrations, ACN completely suppressed THBP chemisorption in the flat (but not in the edgewise) orientation. Extrapolation from these results of adsorption from weak ACN solutions suggests that adsorption of aromatic would be limited to small amounts of edgewise-oriented adsorbate.
Evidence against γ-crystallin DNA or RNA sequences in the chicken

Abstract A cloned cDNA (pMγ1Crl) encoding about two-thirds of a γ-crystallin polypeptide from the murine lens was used as a hybridization probe to search for the presence of γ-crystallin-like RNA or DNA sequences in the chicken. The 15-day-old chicken lens did not contain any RNA sequences homologous to the murine γ-crystallin cDNA, as judged by Northern blot hybridization. An approximate 2·3 Kbp (kilobase pair) Bam HI fragment from the chicken genome hybridized to the murine γ-crystallin cDNA in Southern blots. Cloning and sequencing of this genomic fragment, however, did not reveal any homology with γ- or β-crystallin sequences. A stretch of 22 dG:dC nucleotides was present in the cloned DNA fragment and possibly this hybridized to the cloned γ-crystallin cDNA via its dG:dC nucleotide tails introduced during the cloning procedure. These data support those of McDevitt and Croft (1977) indicating that the chicken lens lacks γ-crystallin and provide evidence against γ-crystallin mRNA or a γ-crystallin gene or pseudogene in the chicken. The absence of γ-crystallin mRNA in the embryonic chicken lens cells makes them potentially useful recipients for investigating the expression of cloned γ-crystallin genes.
Dynamic loads on transmission line structures due to galloping conductors

During ice storms, transmission line systems can be extensively damaged due to galloping conductors. The design of support structures and components requires a means to determine the dynamic forces during galloping. This paper presents a procedure for determining the forces on insulators and crossarms due to the large amplitude vibration of ice-loaded conductors. Wind tunnel experiments were conducted to verify the design procedure and to increase understanding of the galloping phenomenon. >
Vibrotactile pattern isolation/integration.

Temporal integration has been cited as a major factor in temporal masking. Two experiments were designed to examine the conditions under which temporal integration may aid or hinder the perception of vibrotactile spatial patterns. In Experiment 1, the subject’s task was to discriminate between pairs of patterns. Each pattern was composed of two temporally separated pattern elements. When the task required the subjects to perceive the individual pattern elements, performance improved with temporal isolation—that is, performance improved as the temporal separation between the elements increased. In a second task, when the discrimination could be based on either the overall pattern shape or the pattern elements, temporal integration appeared to improve performance—that is, performance improved as the temporal separation decreased. In Experiment 2, an identification task was used. Several factors appeared to determine whether temporal integration aided or hindered pattern identification. When pattern elements similar to those in Experiment 1 were tested, performance improved with increasing temporal separation (isolation). A single function was fit to the discrimination (isolation) and identification (isolation) results. Whether temporal integration aids or hinders pattern perception appears to depend on pattern shape, the pattern elements, and the nature of the task.
AOCS Collaborative Study on Sensory and Volatile Compound Analyses of Vegetable Oils

An AOCS collaborative study was conducted to determine the effectiveness of sensory analysis and gas chromatographic analyses of volatile compounds in measuring vegetable oils for levels of oxidation that ranged from none to high. Sixteen laboratories from industry, government, and academia in Canada and the United States participated in the study to evaluate the flavor quality and oxidative stability of aged soybean, corn, sunflower, and canola (low-erucic acid rapeseed) oils. Analytical methods included sensory analyses with both flavor intensity and flavor quality scales and gas-chromatographic volatiles by direct injection, static headspace, and dynamic headspace (purge and trap) techniques. Sensory and volatile compound data were used to rank each of the oils at four levels of oxidation—none, low, moderate, and high. For soybean, canola, and sunflower oils, 85–90% of laboratories correctly ranked the oils by either analysis. For corn oil, only 60% of the laboratories ranked the samples according to the correct levels of oxidation by either analysis. Variance component estimates for flavor scores showed that the variation between sensory panelists within laboratories was lowest for the unaged oils. As storage time increased, the variance also increased, indicating that differences among panelists were greater for more highly oxidized oils. Between-laboratory variance of sensory panel scores was significantly lower than within-laboratory variance.
The Politics and Experience of Active Love in The Brothers Karamazov

Abstract Contrary to the claims that The Brothers Karamazov is a polyphonic novel, in which the author's own views are irrelevant to its interpretation, and that Dostoevsky himself was unable to furnish an adequate defense of Christianity after Book V, the author shows how Zossima's doctrines of active love and responsibility for all are the interpretive keys to the novel. This so-called “unity in diversity” in Bakhtin's literary criticism thereby provide a compelling alternative vision of community from the Grand Inquisitor's.
Modelling of I-CASE platform

Abstract The two most widely discussed concepts in solving problems of implementation of disassociated computer-aided software engineering (CASE) toolsets are I-CASE (integrated CASE) and C-CASE (component CASE). Although C-CASE is a technologically more advanced concept, its practical realisation is far away yet. Meanwhile, the I-CASE concept offers immediate results to the organizations investing in implementation of CASE toolsets. The article examines an experimental implementation of the I-CASE concept for forward and reverse engineering in the form of the I-CASE Platform, with emphasis on interfaces between toolsets through the central repository. The I-CASE information model is used to analyse the role of the central repository, the global and toolsets' views, dependencies, and connections on the levels of subject areas and meta-data objects.
γ-Aminobutyric Acid Increases the Water Accessibility of M3 Membrane-Spanning Segment Residues in γ-Aminobutyric Acid Type A Receptors

gamma-Aminobutyric acid type A (GABA(A)) receptors are members of the ligand-gated ion channel gene superfamily. Using the substituted cysteine accessibility method, we investigated whether residues in the alpha(1)M3 membrane-spanning segment are water-accessible. Cysteine was substituted, one at a time, for each M3 residue from alpha(1)Ala(291) to alpha(1)Val(307). The ability of these mutants to react with the water-soluble, sulfhydryl-specific reagent pCMBS(-) was assayed electrophysiologically. Cysteines substituted for alpha(1)Ala(291) and alpha(1)Tyr(294) reacted with pCMBS(-) applied both in the presence and in the absence of GABA. Cysteines substituted for alpha(1)Phe(298), alpha(1)Ala(300), alpha(1)Leu(301), and alpha(1)Glu(303) only reacted with pCMBS(-) applied in the presence of GABA. We infer that the pCMBS(-) reactive residues are on the water-accessible surface of the protein and that GABA induces a conformational change that increases the water accessibility of the four M3 residues, possibly by inducing the formation of water-filled crevices that extend into the interior of the protein. Others have shown that mutations of alpha(1)Ala(291), a water-accessible residue, alter volatile anesthetic and ethanol potentiation of GABA-induced currents. Water-filled crevices penetrating into the interior of the membrane-spanning domain may allow anesthetics and alcohol to reach their binding sites and thus may have implications for the mechanisms of action of these agents.
Krogh constants for diffusion of nitrogen and carbon monoxide in bladder tissue.

Abstract We have measured diffusion of N 2 and CO through the walls of urinary bladders of cats. The excised bladders were inflated with various gas mixtures and suspended in air. Values of the Krogh diffusion constants at 37 °C are 1.14 × 10 −5 for N 2 and 1.79 × 10 −5 for CO (units are cm 2 · min −1 · atm −1 and standard errors are less than 10% of the values).
Adrenal Steroid Metabolism in Birds: Anatomy, Physiology, and Clinical Considerations

The hypothalamo-pituitary-adrenal system in birds is anatomically and functionally different from that in mammals. The adrenal gland structure and corticosteroid hormone physiology of birds will be reviewed. The anatomy and physiology sections of this article will be important for better understanding the pathogenesis, diagnosis, and possible treatment of primary or secondary adrenal gland disease. Causes of hyper- and hypoadrenocorticism in birds also will be reviewed. The article will conclude with current indications and complications to the clinical use of glucocorticoids in birds.
Specificity of Memapsin 1 and Its Implications on the Design of Memapsin 2 (β-Secretase) Inhibitor Selectivity†

Memapsin 1 is closely homologous to memapsin 2 (BACE), or β-secretase, whose action on β-amyloid precursor protein (APP) leads to the production of β-amyloid (Aβ) peptide and the progression of Alzheimer's disease. Memapsin 2 is a current target for the development of inhibitor drugs to treat Alzheimer's disease. Although memapsin 1 hydrolyzes the β-secretase site of APP, it is not significantly present in the brain, and no direct evidence links it to Alzheimer's disease. We report here the residue specificity of eight memapsin 1 subsites. In substrate positions P4, P3, P2, P1, P1‘, P2‘, P3‘, and P4‘, the most preferred residues are Glu, Leu, Asn, Phe, Met, Ile, Phe, and Trp, respectively, while the second preferred residues are Gln, Ile, Asp, Leu, Leu, Val, Trp, and Phe, respectively. Other less preferred residues can also be accommodated in these subsites of memapsin 1. Despite the broad specificity, these residue preferences are strikingly similar to those of human memapsin 2 [Turner et al. (2001) Bioc...
Support for hybrid models of the age of acquisition of English nouns

Age of acquisition (AoA) is a psycholinguistic construct that refers to the chronological age at which a given word is acquired. Contemporary theories of AoA have focused on lexical acquisition with respect to either the developing phonological or semantic systems. One way of testing the relative dominance of phonological or semantic contributions is through open-source psycholinguistic databases, whereby AoA may be correlated with other variables (e.g., morphology, semantics, phonology). We report two multiple regression analyses conducted on a corpus of English nouns with, respectively, subjective and objective AoA measures as the dependent variables and a combination of 10 predictors, including 2 semantic, 4 phonological, 2 morphological, and 2 lexical. This multivariate combination of predictors accounted for significant proportions of the variance of AoA in both analyses. We argue that this evidence supports hybrid models of language development that integrate multiple levels of processing—from sound to meaning.
A two-dimensional finite element method for simulating the constitutive response and microstructure of polycrystals during high temperature plastic deformation

We describe a finite element method designed to model the mechanisms that cause superplastic deformation. Our computations account for grain boundary sliding, grain boundary diffusion, grain boundary migration, and surface diffusion, as well as thermally activated dislocation creep within the grains themselves. Front tracking and adaptive mesh generation are used to follow changes in the grain structure. The method is used to solve representative boundary value problems to illustrate its capabilities.
Spectrum Sensing Using Cyclostationary Spectrum Density for Cognitive Radios

Cognitive radios (CR) are proposed to alleviate the spectrum scarcity problems facing wireless service providers. In US, the FCC is considering spectrum regulation changes by allowing unlicensed operation in the TV broadcast bands provided that no harmful interference is caused. In this paper, we discuss the spectrum sensing aspects of cognitive radios. We particularly focus on the detection method based on cyclostationary spectrum density (CSD) estimation. The advantage of CSD is its relative robustness against noise uncertainty compared with energy detection methods. CSD estimation is a two dimensional transformation; therefore it is computationally complex. We transform the algorithm from the two dimensional space to a one dimensional case, therefore making the real time implementation more feasible. Through analysis and simulation, we identify the features with highest SNR to be used for CSD based detection. Based on the simulation results, we further propose dedicated hardware implementation architecture for CSD estimation using field programmable logic array (FPGA). Our implementation can achieve greater than 90% detection probability on BPSK signals with SNR of -18 dB, when the probability of false alarm is less than 10%.
A novel Ccb and Rb reduction technique for high-speed SiGe HBTs

In this paper, we discuss a novel technique to reduce base resistance (R b ) and collector-base capacitance (C cb ) for higher F max in high-speed SiGe HBTs. In order to reduce C cb , we first located the origins of the different components of C cb through AC extraction. Then we utilized scanning capacitance measurements (SCM) to examine the shape of the collector-base depletion. We then propose a method to reduce the extrinsic C cb , namely by using reticle enhancement techniques to print a blocking oxide layer to inhibit boron outdiffusion. An additional benefit was the reduction of R b by reducing the base link resistance.
Estimation of oceanic surface velocity fields using wavelets

This paper presents a new method for the estimation of oceanic surface velocity fields using wavelet decomposition of Sea Surface Temperature images (SST). This method requires the use of two SST images of the same region taken within a known time interval. Wavelet decompositions are performed on both images to obtain approximations that will be compared for local displacements. These local displacements are smoothed to eliminate noise and to generate a rough initial estimate of the velocity field. Then this estimate is iteratively refined by a similar analysis over more detailed images produced by inverse wavelet transforms. A description of the method and its assumptions are presented with initial results.
Military Training and Road Effects on Imperata cylindrica (L.) Beauv. (Cogongrass)

Type, level, and intensity of human activities may facilitate establishment and spread of invasive plant species. A better understanding of how human activities infl uence invasion can assist land managers in developing strategies for control and monitoring of invasive plants. Spread of the invasive species Imperata cylindrica (Cogongrass) has been attributed to human activities. During 2002I 2004, on Camp Shelby Training Site, MS, we investigated relationships between military activity and establishment and growth of Cogongrass. In areas of soil disturbance from mili- tary equipment, vegetative linear growth rates of 7I 10 m yr -1 were recorded on fi ring points. There was a positive relationship between military troop use and Cogongrass establishment on fi ring points for one of the 2 years of the study (P = 0.023). Thus, steps to minimize soil disturbance in and near Cogongrass may reduce spread. We examined frequency of Cogongrass infestation and vegetative growth rates for road- side areas along gravel roads subject to at least annual mowing and grading, and dirt tracks receiving infrequent maintenance. Cogongrass spread and establishment on roadsides did not differ for the two road types (Pi 0.116). These results may refl ect activities already in place to reduce disturbance of Cogongrass patches.
Preparation of the group VI pentacarbonyl nitrates

Abstract Pentacarbonyl nitrate anions of Cr and W have been prepared by reaction of tetraethylammonium nitrate with the photochemically generated M(CO) 5 THF intermediates.
Continuing education for health professionals as part of a broader experiment in health education--Health Care Expo '85: a case report.

Health Care Expo ′85s was an experiment in health education, combining education for the public, physicians and nurses in one site (a convention center) over 1 week. The educational formats were primarily lectures, seminars and educational exhibits. The attendance by each type of participant was disappointing. Overall, the education for the physicians and nurses was rated highly, although there was little interest on the part of health professionals in the exhibits or the parts of the program addressed to the public. The lack of success in terms of money and attendance was probably related to the timing, possibly the location, the tuition, the concept of combining education for several groups in one location, and insufficient advertising. Anyone considering such a combined endeavor will need to address these issues to improve the chances of success.
Improving MapReduce energy efficiency for computation intensive workloads

MapReduce is a programming model for data intensive computing on large-scale distributed systems. With its wide acceptance and deployment, improving the energy efficiency of MapReduce will lead to significant energy savings for data centers and computational grids. In this paper, we study the performance and energy efficiency of the Hadoop implementation of MapReduce under the context of energy-proportional computing. We consider how MapReduce efficiency varies with two runtime configurations: resource allocation that changes the number of available concurrent workers, and DVFS (Dynamic Voltage and Frequency Scaling) that adjusts the processor frequency based on the workloads' computational needs. Our experimental results indicate significant energy savings can be achieved from judicious resource allocation and intelligent DVFS scheduling for computation intensive applications, though the level of improvements depends on both workload characteristic of the MapReduce application and the policy of resource and DVFS scheduling.
Hyperoxic brain effects are normalized by addition of CO2.

Author(s): Macey, Paul M; Woo, Mary A; Harper, Ronald M | Abstract: BackgroundHyperoxic ventilation (g21% O2) is widely used in medical practice for resuscitation, stroke intervention, and chronic supplementation. However, despite the objective of improving tissue oxygen delivery, hyperoxic ventilation can accentuate ischemia and impair that outcome. Hyperoxia results in, paradoxically, increased ventilation, which leads to hypocapnia, diminishing cerebral blood flow and hindering oxygen delivery. Hyperoxic delivery induces other systemic changes, including increased plasma insulin and glucagon levels and reduced myocardial contractility and relaxation, which may derive partially from neurally mediated hormonal and sympathetic outflow. Several cortical, limbic, and cerebellar brain areas regulate these autonomic processes. The aim of this study was to assess recruitment of these regions in response to hyperoxia and to determine whether any response would be countered by addition of CO2 to the hyperoxic gas mixture.Methods and findingsWe studied 14 children (mean age 11 y, range 8-15 y). We found, using functional magnetic resonance imaging, that 2 min of hyperoxic ventilation (100% O2) following a room air baseline elicited pronounced responses in autonomic and hormonal control areas, including the hypothalamus, insula, and hippocampus, throughout the challenge. The addition of 5% CO2 to 95% O2 abolished responses in the hypothalamus and lingual gyrus, substantially reduced insular, hippocampal, thalamic, and cerebellar patterns in the first 48 s, and abolished signals in those sites thereafter. Only the dorsal midbrain responded to hypercapnia, but not hyperoxia.ConclusionsIn this group of children, hyperoxic ventilation led to responses in brain areas that modify hypothalamus-mediated sympathetic and hormonal outflow; these responses were diminished by addition of CO2 to the gas mixture. This study in healthy children suggests that supplementing hyperoxic administration with CO2 may mitigate central and peripheral consequences of hyperoxia.
Essential role of the cAMP-cAMP response-element binding protein pathway in opiate-induced homeostatic adaptations of locus coeruleus neurons

Excessive inhibition of brain neurons in primary or slice cultures can induce homeostatic intrinsic plasticity, but the functional role and underlying molecular mechanisms of such plasticity are poorly understood. Here, we developed an ex vivo locus coeruleus (LC) slice culture system and successfully recapitulated the opiate-induced homeostatic adaptation in electrical activity of LC neurons seen in vivo. We investigated the mechanisms underlying this adaptation in LC slice cultures by use of viral-mediated gene transfer and genetic mutant mice. We found that short-term morphine treatment of slice cultures almost completely abolished the firing of LC neurons, whereas chronic morphine treatment increased LC neuronal excitability as revealed during withdrawal. This increased excitability was mediated by direct activation of opioid receptors and up-regulation of the cAMP pathway and accompanied by increased cAMP response-element binding protein (CREB) activity. Overexpression of a dominant negative CREB mutant blocked the increase in LC excitability induced by morphine- or cAMP-pathway activation. Knockdown of CREB in slice cultures from floxed CREB mice similarly decreased LC excitability. Furthermore, the ability of morphine or CREB overexpression to up-regulate LC firing was blocked by knockout of the CREB target adenylyl cyclase 8. Together, these findings provide direct evidence that prolonged exposure to morphine induces homeostatic plasticity intrinsic to LC neurons, involving up-regulation of the cAMP-CREB signaling pathway, which then enhances LC neuronal excitability.
Multiple FadD acyl-CoA synthetases contribute to differential fatty acid degradation and virulence in Pseudomonas aeruginosa.

A close interconnection between nutrient metabolism and virulence factor expression contributes to the pathophysiology of Pseudomonas aeruginosa as a successful pathogen. P. aeruginosa fatty acid (FA) degradation is complicated with multiple acyl-CoA synthetase homologs (FadDs) expressed in vivo in lung tissue during cystic fibrosis infections. The promoters of two genetically linked P. aeruginosa fadD genes (fadD1 and fadD2) were mapped and northern blot analysis indicated they could exist on two different transcripts. These FadDs contain ATP/AMP signature and FA-binding motifs highly homologous to those of the Escherichia coli FadD. Upon introduction into an E. coli fadD-/fadR- double mutant, both P. aeruginosa fadDs functionally complemented the E. coli fadD-/fadR- mutant, allowing degradation of different chain-length FAs. Chromosomal mutagenesis, growth analysis, induction studies, and determination of kinetic parameters suggested that FadD1 has a substrate preference for long-chain FAs while FadD2 prefers shorter-chain FAs. When compared to the wild type strain, the fadD2 mutant exhibited decreased production of lipase, protease, rhamnolipid and phospholipase, and retardation of both swimming and swarming motilities. Interestingly, fadD1 mutant showed only increased swarming motility. Growth analysis of the fadD mutants showed noticeable deficiencies in utilizing FAs and phosphatidylcholine (major components of lung surfactant) as the sole carbon source. This defect translated into decreased in vivo fitness of P. aeruginosa in a BALB/c mouse lung infection model, supporting the role of lipids as a significant nutrient source for this bacterium in vivo.
Temporal changes in the incidence of malignant melanoma: Explanation from action spectra

The incidence of malignant cutaneous melanoma has been increasing for more than 50 years, and is now rising more rapidly than that of any other cancer. This increase is not explicable by changes in the physical environment, particularly by any observed increase in UVB radiation (290–320 nm). The distribution of melanomas on the body differs from the site distribution of nonmelanoma skin cancer (relatively many more melanomas occur on areas of the body not chronically exposed to sunlight, such as the back of the trunk in males, and the legs in females.) This localization of melanoma, together with its epidemiology, suggest that a change in lifestyle has contributed to the fast-rising incidence in many countries. There is no convenient mammalian animal model for malignant melanoma. However, certain inter- and intra-specific hybrids of fish of the genus Xiphophorus are very sensitive to light-induced melanomas; we have used them to determine the wavelengths effective in melanoma induction. The action spectrum has a relatively very large component in the UVA region (320–400 nm) compared to human erythema. Hence, if the human and fish spectra were similar, the use of sunscreens that minimize erythema would have little effect in preventing the induction of melanoma, and if people using sunscreens expose themselves to sunlight for longer periods, they will be increasing dramatically their exposure to these melanoma-inducing wavelengths. Such considerations are sufficient to explain the rising incidence of malignant melanoma and its distribution on the body.
Double-layer porcelain veneers: effect of layering on resulting veneer color.

Abstract Statement of problem. Densely sintered aluminum oxide veneered with feldspathic porcelain seems to be a promising technology for the fabrication of porcelain laminate veneers, which provide both strength and esthetics. To effectively use this approach for porcelain veneers, practitioners should know how the resulting color is affected by adding a layer of veneering porcelain onto the aluminum oxide. Purpose. This study compared changes in CIE L*a*b* color coordinates of simulated stained teeth when covered with the aluminum oxide core disks alone and after the disks had been veneered with 3 different shades of porcelain. Material and methods. Fifteen aluminum oxide disks were divided into 3 groups. Each of 5 disks was veneered with porcelain of the Vita shades A1, A2, and B4, respectively. The colors of the substrate covered with the nonveneered disks and the veneered disks were measured separately, and the color differences were calculated. Measurements of the disks on a white background were also performed and used as controls. The extracted data were compared with Vita shade values available from the literature. Results. Statistically significant differences in color coordinates of dark substrates were recorded between the substrate covered by an aluminum oxide disk and the addition of veneering porcelain to the aluminum oxide disks. Veneering the aluminum oxide disks with A1, A2, and B4 porcelain produced significant differences in the resulting color when placed on a dark substrate. The direction of the color modifications correlated with values obtained from the literature. The resulting color was also affected by the color of the underlying structures. Conclusion. Although aluminum oxide alone does have a degree of masking capability, the resulting color of porcelain veneers with the use of this material can successfully be modified with the veneering porcelain. (J Prosthet Dent 2000;84:425-31.)
The Combination of Protriptyline and Oxazepam in Depressed Neurotic General Practice Patients

• Although depression or anxiety may be the predominant symptom, patients frequently suffer from a combination of the two, regardless of which is the basic diagnosis. This fact reflects the need for treatment agents which combine anti-depressant and anti-anxiety effects. Protriptyline is a recognized anti-depressant without tranquilizing properties. It was considered worthwhile to test the efficacy of protriptyline in combination with oxazepam, an anti-anxiety agent, in the treatment of non-psychotic, primarily neurotic, depressed outpatients suffering also to varying degrees from concomitant symptoms of anxiety. In a study previously conducted by this research group, meprobamate in combination with protriptyline counteracted the stimulatory effects of protriptyline and contributed to a swifter response'. In the present study, the question was raised whether oxazepam, a diazepine derivative, combined with protriptyline in two fixed ratios, might act similarly and be differentiated significantly from placebo without excessive side effects. If this study should demonstrate significantly better effects for one or both of the drug ratios over placebo, then a larger controlled study may be planned to compare the combination against its constituents.
SU-E-J-193: Feasibility of MRI-Only Based IMRT Planning for Pancreatic Cancer

Purpose: With the increasing use of MRI simulation and the advent of MRI-guided delivery, it is desirable to use MRI only for treatment planning. In this study, we assess the dosimetric difference between MRI- and CTbased IMRT planning for pancreatic cancer. Methods: Planning CTs and MRIs acquired for a representative pancreatic cancer patient were used. MRI-based planning utilized forced relative electron density (rED) assignment of organ specific values from IRCU report 46, where rED = 1.029 for PTV and a rED = 1.036 for non-specified tissue (NST). Six IMRT plans were generated with clinical dose-volume (DV) constraints using a research Monaco planning system employing Monte Carlo dose calculation with optional perpendicular magnetic field (MF) of 1.5T. The following five plans were generated and compared with the planning CT: 1.) CT plan with MF and dose recalculation without optimization; 2.) MRI (T2) plan with target and OARs redrawn based on MRI, forced rED, no MF, and recalculation without optimization; 3.) Similar as in 2 but with MF; 4.) MRI plan with MF but without optimization; and 5.) Similar as in 4 but with optimization. Results: Generally, noticeable differences in PTV point doses and DV parameters (DVPs) between the CT-and MRI-based plans with and without the MF were observed. These differences between the optimized plans were generally small, mostly within 2%. Larger differences were observed in point doses and mean doses for certain OARs between the CT and MRI plan, mostly due to differences between image acquisition times. Conclusion: MRI only based IMRT planning for pancreatic cancer is feasible. The differences observed between the optimized CT and MRI plans with or without the MF were practically negligible if excluding the differences between MRI and CT defined structures.
Plastic eternities and the mosaic of landscape

In recent years nonrepresentational theory has been applied with increasing frequency to landscape studies. This paper responds to this trend in two ways. First, through a close reading of John Wylie and Mitch Rose's writings, I critique the application of nonrepresentational theory to landscape interpretation. While nonrepresentational theory has, crucially, highlighted the importance of performativity, affect, excess, and relationality, it has been imperfectly translated to landscape studies. Landscape studies grounded in nonrepresentational theory overburden the landscape with philosophical and theoretical propositions, which has the effect of exonerating landscapes from their temporal, spatial, and visual circumstances. Second, drawing mainly on the work of Catherine Malabou and Bruno Latour, I suggest that different metaphors and concepts are needed to improve land- scape studies: plasticity and a revamped, historical account of relationality. The aim of this paper is to establish a means of visualizing the dynamics of landscape and their historical mutability, with the intention of producing readings that are more ecumenical, and avoid the theoretical reductionism found in current nonrepresentational accounts of landscape.
Performance and emission characteristics of butanol/Jet A blends in a gas turbine engine

Abstract Butanol, which can be derived from biomass, is an attractive alternative energy resource to petroleum fuels. Recently, butanol seems to be preferred over other alcohols, particularly for blending with petroleum fuels such as gasoline/Jet A, because its properties are closer to those of the latter. The focus of this study was the effect of butanol/Jet A blends on the performance and emission characteristics of a gas turbine engine. Pure Jet A, butanol and their blends with varying concentrations of butanol, ranging from 25% to 75% by volume, were used as fuels. The performance characteristics, the thrust, thrust-specific fuel consumption, turbine inlet temperature and exhaust gas temperature, and the emission characteristics, such as thrust-specific emission indices of CO and NOx, were measured over a range of throttle settings. The operational thrust range of the engine for butanol-containing fuels was reduced when compared to that of Jet A fuel. The NOx and CO emission indices were lower for butanol and butanol blends compared to those with Jet A.
Current Treatment of Blow-out Fractures

Blow-out fracture repair and its timing have been controversial. Originally all x-ray proven fractures were repaired regardless of size or symptoms. Later a controversial report of a large series of cases indicated repair to be unnecessary. Today, x-ray proven fractures with enophthalmos justify surgery, but double vision alone is insufficient. Observation of improving diplopia for several days is suggested. Evaluation of x-rays, enophthalmos, diplopia with restriction, and facial anesthesia are recommended before surgery. Recognition of diagnostic signs and symptoms, as well as potential severe cosmetic and functional complications, have aided the approach to the decision for or against fracture repair.
Why is life stress ignored in studies of 'stress' and athletic performance?

Investigations of relationships between stress and athletic performance and stress and outcomes outside of sport psychology have a parallel evolution. Each area has advanced from early attempts to ...
Antibiotic Binding to Dizinc β-Lactamase L1 from Stenotrophomonas maltophilia: SCC-DFTB/CHARMM and DFT Studies†

A dizinc β-lactamase (L1 from Stenotrophomonas maltophilia) complexed with an antibiotic compound (moxalactam) has been studied using a hybrid quantum mechanical/molecular mechanical (QM/MM) approach. The QM region is described by the self-consistent charge-density functional tight binding (SCC-DFTB) model while the MM by CHARMM. The Michaelis complex, which is constructed from a recent X-ray structure of the L1 enzyme with the hydrolyzed moxalactam, is simulated by molecular dynamics. The simulation yields valuable insights into substrate-enzyme interaction, whose implications in the enzyme catalysis are discussed. Finally, the QM/MM results are compared with a high-level density functional theory study of a truncated active-site model and the agreement provides strong support for the SCC-DFTB treatment of the QM region.
Integrating active shape models into ultrasound elastography to diagnose musculoskeletal injuries: A 2D simulation study

We build on ultrasound elastography (UE) by offering a new method for diagnosing musculoskeletal injuries from estimated tissue displacements. Our strategy is to isolate the portion of tissue displacements that arise due to injury. Active shape models are constructed capturing displacement variation among normal tissue. New tissue is then evaluated by estimating displacements with (1) the active shape models and (2) a traditional UE tracking algorithm. The difference between the two estimates defined virtual axial displacement and used to identify injured tissue. Our method was tested by simulating planar tissue examined with ultrasound elastography. Images are presented of axial displacement and virtual axial displacement as well as axial strain and virtual axial strain, i.e. partial derivative of the respective displacements with respect to the axial coordinate. Injured tissue and uninjured tissue were not statistically different when comparing mean absolute value of axial strain covarying with the loading conditions. In contrast, uninjured tissue and injured tissue were statistically different when comparing absolute value of virtual axial strain covarying with loading conditions (p < 0.0001). Statistical significance was considered p < 0.05.