cssi/SciSciGPT-SciSciNet huggingface dataset:
Determination of the Conformations of cAMP Receptor Protein and Its T127L,S128A Mutant with and without cAMP from Small Angle Neutron Scattering Measurements

Abstract Small angle neutron scattering (SANS) measurements were performed on solutions of cAMP receptor protein (CRP) and on solutions of the T127L,S128A double mutant of CRP (CRP*) in D2O K3PO4 buffer containing 0.5 m KCl, in the absence and presence of 3′,5′ cyclic adenosine monophosphate (cAMP). Energy-minimized structures of the CRP were calculated by minimization of the x-ray crystallographic structure of CRP in either the exclusively “closed” form where the α-helices of the carboxyl-terminal domain are folded close to the amino-terminal domain and in the exclusively “open” form where the α-helices of the carboxyl-terminal domain are folded away from the amino-terminal domain. Neutron scattering models show that the CRP SANS data follow closely the data curve predicted for unligated CRP in the open form, whereas the cAMP-ligated data are more in agreement with the data predicted for the minimized cAMP-ligated CRP structure in the closed form. Thus, it appears that CRP undergoes a conformational change from the open form to the closed form in solution upon ligation with cAMP. The SANS data from the CRP* and cAMP-ligated CRP* are coincidental, which implies that there is very little structural difference between the two species of CRP*. This is in agreement within vivo results, which show that whereas CRP activates transcription in the cell only in the presence of cAMP, CRP* activates transcription in the absence of cAMP, implying that CRP* is already in the correct conformation for the activation of transcription.
Endothelial Expression of Bone Morphogenetic Protein Receptor Type 1a is Required for Atrioventricular Valve Formation

Background Atrioventricular canal defects account for 4% of all congenital heart anomalies. They arise from failure of endocardial cushion formation, a process dependent on transition of endothelial cells into clustered mesenchymal cells in the mid–atrioventricular septum. To date, the genetic signals necessary for atrioventricular canal defects are poorly understood. We hypothesized that bone morphogenetic protein signaling in cardiac endothelial cells may be crucial to this process. Methods To study the role of bone morphogenetic protein receptors (Bmpr) in the developing heart, we created knockout mice with inactivation of Bmpr1a selectively in endocardium. Two strains of null mice were created: one with constitutive endothelial-specific knockout of Bmpr1a and one with time-inducible, endothelial-specific knockout of Bmpr1a. Embryos and animals were analyzed by microscopy, RNA in situ hybridization, and microangiography. Results Animals with null mutation of Bmpr1a in endothelium were embryonic lethal at E11.5 to 12.0 and demonstrated absence of endocardial cushion formation. Embryos failed to form atrioventricular valves and adjacent septa. Endocardial knockout of Bmpr1a did not affect development of the outflow tract or aortic arches. Using time-inducible, cell-specific knockout mice, we show that Bmpr1a has two functions in the developing atrioventricular canal: to induce endocardial endothelial-mesenchymal transition, and to pattern the septal mesenchyme into endocardial cushions. We demonstrate that these processes are temporally linked to expression of the transcription factors Id1 and Id3. Conclusions Endocardial cushion formation is dependent on cell-specific expression of Bmpr1a. Our results suggest that Bmpr1a-mediated signaling is a crucial pathway involved in pathogenesis of atrioventricular septal and valve malformations, which are among the most common congenital heart defects in humans.
Systematic Study of Transparent Conductors in the (Zinc, Gallium)-Indium-Tin Oxide Systems

Bulk samples of transparent conducting oxides (TCOs) in the Zn-In-Sn and Ga-In-Sn oxide systems were prepared by solid state processing. Phase relations and physical properties were determined and the results compared to similar measurements on thin film materials.
How to manage conflicts of interest with industry

The use of medications has risen steadily in psychiatry. Perhaps in response, during the past few years there has been increasing scrutiny of alleged unethical behaviours by medical researchers, educators, and practitioners secondary to influence by the pharmaceutical industry. Research is quite consistent that gifts and generous financial arrangements can dampen skepticism, sometimes unconsciously, and thereby persuade recipients to advocate for or prescribe medications that are more expensive, but no more effective, than alternatives. Interestingly, this research-backed premise that physicians can be lured by gifts remains often disbelieved by recipients. Adding to such inducements to prescribe new, expensive medications are pressures from patients due to the increasing ubiquity of direct-to-consumer advertising.Criticism from patient advocate groups, government agencies, and the press has sparked debate within the profession. Many medical journals, academic medical centre research and educational endea...
The retest reliability of nicotine dependence measures

Aim: As reliable instruments are needed for longitudinal research on the development of nicotine addiction, we evaluated the test–retest reliability of eight survey measures (three scales and five individual item measures).Methods: A paper survey was administered to convenience samples of adolescents in two schools and adults in five workplaces in Argentina and re-administered 1–2 weeks later. Test–retest reliability was assessed with Pearson correlations for continuous measures and kappa statistics for dichotomous measures.Results: Both surveys were completed by 95 adolescent and 88 adult smokers. The modified Fagerstrom Tolerance Questionnaire (r = 0.88–0.91), the Hooked on Nicotine Checklist (r = 0.85–0.91), the Autonomy Over Smoking Scale (0.91–0.96) and items assessing latency to needing a cigarette (r = 0.85–0.94), the pleasure obtained from smoking (r = 0.84–0.94), and relaxation obtained from the first cigarette (κ = 0.63–0.67), all showed very good to excellent reliability in both populations. It...
Regulation of HIV-1 protease activity through cysteine modification.

The homodimeric protease of the human immunodeficiency virus 1 contains two cysteine residues per monomer which are highly conserved among viral isolates. However, these cysteine residues are not essential for catalytic activity which raises the question of why they are conserved. We have found previously that these cysteine residues are unusually susceptible to oxidation by metal ions, and this results in inhibition of protease activity. Recombinant protease mutants (C67A, C95A, and the double mutant C67A,C95A) were prepared to assess the possible role of these cysteines in redox regulation of the enzyme. Mixed disulfides were formed between the cysteine residues of the enzymes and low molecular weight thiols. Enzyme activity was lost when a mixed disulfide was formed between 5,5‘-dithiobis(2-nitrobenzoic acid) and cysteine 95, while the same mixed disulfide at cysteine 67 reduced activity by 50%. This effect was reversible as normal activity could be restored when the enzyme was treated with dithiothrei...
Finite-element-based computationally-efficient electric machine model suitable for use in electrified vehicle powertrain design optimization

Electric machines and their corresponding power electronic drives are key components of electric/hybrid electric vehicle (EV/HEV) powertrains. Thus, computationally-efficient models for electric machines and drives are essential for powertrain-level design, simulation, and optimization. In this paper, a finite-element-based method for quickly generating torque-speed curves and efficiency maps for electric machines and drives is presented. First, magneto-static finite element analysis (FEA) is conducted on a “base” machine design. This analysis produces normalized torque, flux linkage, current, and losses for the operating points of interest. These values are then adjusted based upon changing the size of the machine and the effective number of turns of the machine windings to quickly generate a variety of new machine designs and their corresponding efficiency maps. Results suggest that the proposed techniques can be useful for EV/HEV powertrain design and optimization.
Creating the Standard Desktop Environment in a Non-Standard World

The purpose of this paper is to give user services staff an overview of issues to consider when trying to standardize desktop environments and deliver software upgrades to faculty, staff and students, as well as to provide some tried and true solutions to these problems.
An Office-based Orthotic System in Treatment of the Arthritic Foot

Patients with inflammatory arthritic disease of the feet invariably require conservative office management. The simplest method of obtaining relief has been to use commercially available extra-depth shoes combined with custommade, removable, closed-celled polyethylene foam arch supports. These supports are soft, light, and can be accurately adjusted to each patient's pathology. The technique and modifications used for relieving the commonest problems, such as anterior metatarsalgia and plantar heel pain, are discussed.
Strain gradients and size effects in nonhomogeneous plastic deformation

Phenomenological constitutive equation for plastic deformation in metallic alloys are usually developed with the basic assumption of uniformity of the deformation field, or by the homogenization of the field over a macroscopic representative element. This, in turn, coupled with simple nondimensional analysis within the classical continuum theory of plasticity, leads to the development of homogeneous constitutive equations that relate the flow stress to some internal variables, such as strain hardening, strain rate, and volume fraction of second phase particles in metal matrix composites. However, there are circumstances where the size of the microstructure significantly influences the overall mechanical properties of the material. This becomes even more crucial when the size of the plastic deformation zone and the magnitude of the strain gradient within it become comparable to the size of the underlying dislocation structure. For example, predicting the width of the shear band in metallic alloys and its scaling with the size of the microstructure is an important issue from a fundamental point of view. A constitutive model that can capture this phenomenon can also provide an explanation of other observed phenomena such as the size of the plastic zone near a crack tip, the dependence of flow stress onmore » particle size in metal matrix composite, the effect of specimen size on the stress-strain curve in pure copper, and the significant increase in flow stress observed in indentation tests when the size of the indenter is in the nanometer range. The objective of this paper is to provide a possible explanation of how a local microscopic strain inhomogeneity resulting from a heterogeneous microstructure can generate a strain gradient effect when the deformation field is averaged over a macroscopic representative element, leading to a specific predictive relation for the strain gradient coefficient c in terms of the materials elastic-plastic moduli and grain size.« less
Purine metabolism in Trypanosoma cruzi.

Abstract Culture forms of Trypanosoma cruzi are incapable of synthesizing purines de novo from formate, glycine, or serine and require an exogenous purine for growth. Adenine, hypoxanthine, guanine, xanthine and their respective ribonucleosides are equal in their abilities to support growth. Radiolabeled purine bases, with the exception of guanine, are stable and are converted to their respective ribonucleotides directly by phosphoribosyltransferase activity. Guanine is both converted to its ribonucleotide and deaminated to xanthine. Purine nucleosides are not hydrolysed to any extent but are converted to their respective ribonucleotides. This conversion may involve a rate-limiting ribonucleoside cleaving activity or a purine nucleoside kinase or phosphotransferase activity. The apparent order of salvage efficiency for the bases and their respective ribonucleosides is adenine > hypoxanthine > guanine > xanthine.
Gaussian beam depth migration for anisotropic media

Gaussian beam migration (GBM), as it is implemented today, efficiently handles isotropic inhomogeneous media. The approach is based on the solution of the wave equation in ray‐centered coordinates. Here, I extend the method to work for 2-D migration in generally anisotropic inhomogeneous media. Extension of the Gaussian‐beam method from isotropic to anisotropic media involves modification of the kinematics and dynamics in the required ray tracing. While the accuracy of the paraxial expansion for anisotropic media is comparable to that for isotropic media, ray tracing in anisotropic media is much slower than that in isotropic media. However, because ray tracing is just a small portion of the computation in GBM, the increased computational effort in general anisotropic GBM is typically only about 40%. Application of this method to synthetic examples shows successful migration in inhomogeneous, transversely isotropic media for reflector dips up to and beyond 90°. Further applications to synthetic data of lay...
Compressive mica seals for solid oxide fuel cells

Sealing technology is currently considered a top-priority task for planar solid oxide fuel-cell stack development. Compressive mica seals are among the major candidates for sealing materials due to their thermal, chemical, and electrical properties. In this paper, a comprehensive study of mica seals is presented. Two natural micas, muscovite and phlogopite, were investigated in either a monolithic single-crystal sheet form or a paper form composed of discrete mica flakes. A “hybrid” mica seal, developed after identification of the major leak paths in compressive mica seals, demonstrated leak rates that were hundreds to thousands times lower than leak rates for conventional mica seals. The hybrid mica seals were further modified by infiltration with wetting materials; these “infiltrated” micas showed excellent thermal cycle stability with very low leak rates (10−3 sccm/cm). The micas were also subjected to studies to evaluate thermal stability in a reducing environment as well as the effect of compressive stresses on leak rates. In addition, long-term open circuit voltage measurements versus thermal cycling showed constant voltages over 1,000 cycles. The comprehensive study clearly demonstrated the potential of compressive mica seals as sealing candidates for solid oxide fuel cells.
Interaction of Charge Carriers with Lattice Vibrations in Organic Molecular Semiconductors: Naphthalene as a Case Study

Recent theoretical studies suggest that the modulation of the electronic couplings (transfer integrals) between adjacent molecules by lattice vibrations, i.e., the so-called nonlocal electron−phonon coupling, plays a key role in the charge-transport properties of molecular organic semiconductors. However, a detailed understanding of this mechanism is still missing. Here, we combine density functional theory calculations and molecular mechanics simulations and use a chemistry-based insight to derive the nonlocal electron−phonon coupling constants due to the interaction of charge carriers with the optical lattice vibrations in the naphthalene crystal. The results point to a very strong coupling to both translational and librational intermolecular vibrational modes as well as to intramolecular modes. Along some crystal directions, the nonlocal interactions are found to be dominated by nontotally symmetric vibrational modes which lead to an alternation (Peierls-type dimerization) pattern. Importantly, we intr...
Horizontal gene transfer, genome innovation and evolution

To what extent is the tree of life the best representation of the evolutionary history of microorganisms? Recent work has shown that, among sets of prokaryotic genomes in which most homologous genes show extremely low sequence divergence, gene content can vary enormously, implying that those genes that are variably present or absent are frequently horizontally transferred. Traditionally, successful horizontal gene transfer was assumed to provide a selective advantage to either the host or the gene itself, but could horizontally transferred genes be neutral or nearly neutral? We suggest that for many prokaryotes, the boundaries between species are fuzzy, and therefore the principles of population genetics must be broadened so that they can be applied to higher taxonomic categories.
Propagation in tissue cultures of a cytopathogenic virus from human salivary gland virus (SGV) disease.

ConclusionsA cytopathogenic virus inducing large intranuclear inclusions like those occurring in salivary gland virus disease has been isolated from the tissues of each of 2 infants. In both cases ...
Engineering 3D metal nanoantenna for fluorescence enhancement

We examine the fluorescence enhancements from various 3D metallic nanoantenna/molecules structures with different antenna shapes, metal types and spacer-molecule lengths. The results allow us to engineer optimal metallic structures for the fluorescence enhancement.
Virtuality and Team Performance: Understanding the Impact of Variety of Practices

AbstractIn many corporations today, it is common to have teams with members located in different geographic locations, different time zones, and even different countries. These virtual teams are strategically important to organizations as they adapt to constantly changing market and political conditions such as global outsourcing. Despite the research and investment in technologies supporting virtual work, it remains unclear how virtuality, or the conditions under which virtual teams work, affects performance. Prior research suggests performance of virtual teams runs the gamete from failure to success. A global understanding of the specific impacts of virtual work on performance, positive or negative, remains elusive because researchers have not yet ascertained which aspects of virtuality are especially relevant in a given setting.In this study conducted at Intel Corporation, we examine how different components of virtuality influence specific aspects of performance of virtual teams. We use both quantitat...
Quantifying the activity of anti-HIV treatment in silico.

Combination-based antiretroviral therapy has been very successful in preventing disease progression in HIV-infected individuals. However, a rational method for predicting the effect of a particular drug combination on clinical outcome is needed. A new study takes us closer to this goal by computationally predicting the inhibitory effects of combinations of three antiretroviral drugs (pages 446–451).
Extension of Multiprotocol Label Switching for long-range dependent traffic: QoS routing and performance in IP networks

Abstract This paper presents an extension to the Multiprotocol Label Switching (MPLS) traffic engineering in IP networks with long-range dependent traffic. The extension provides the ability to diverge traffic flows away from the shortest path calculated by the traditional IP routing protocols into a less congested area of the network. When the traffic burstiness of a packet flow exceeds a predefined threshold, the extension calculates the cost of the traffic distribution and the effectiveness of Label Switching Routers (LSPs) to minimize the number of discarded packets. The simulation results demonstrate that the extension significantly improves the overall network performance in link utilization, port processor utilization, message delay, number of dropped packets, and buffer usage level.
Modeling surf zone tracer plumes: 1. Waves, mean currents, and low‐frequency eddies

[1] A model that accurately simulates surf zone waves, mean currents, and low‐frequency eddies is required to diagnose the mechanisms of surf zone tracer transport and dispersion. In this paper, a wave‐resolving time‐dependent Boussinesq model is compared with waves and currents observed during five surf zone dye release experiments. In a companion paper, Clark et al. (2011) compare a coupled tracer model to the dye plume observations. The Boussinesq model uses observed bathymetry and incident random, directionally spread waves. For all five releases, the model generally reproduces the observed cross‐shore evolution of significant wave height, mean wave angle, bulk directional spread, mean alongshore current, and the frequency‐dependent sea surface elevation spectra and directional moments. The largest errors are near the shoreline where the bathymetry is most uncertain. The model also reproduces the observed cross‐shore structure of rotational velocities in the infragravity (0.004 < f < 0.03 Hz) and very low frequency (VLF) (0.001 < f < 0.004 Hz) bands, although the modeled VLF energy is 2–3 times too large. Similar to the observations, the dominant contributions to the modeled eddy‐induced momentum flux are in the VLF band. These eddies are elliptical near the shoreline and circular in the mid surf zone. The model‐data agreement for sea swell waves, low‐frequency eddies, and mean currents suggests that the model is appropriate for simulating surf zone tracer transport and dispersion.
Trusting the Internet: Cues Affecting Perceived Credibility

Positive beliefs about the validity and reliability of website information are important for users and the success of a site. Users may use these beliefs in making judgments about the veracity of the informational content that they encounter on the Internet. This research examined several components associated with Web sites that could affect credibility beliefs about Web site information: domain suffixes (e.g., .com, .edu), quality seals, and organizations/domain names. Two studies were carried out involving a total of 433 participants. One had 247 participants (171 undergraduates and 76 non-student adults) and the other had 186 participants (89 undergraduates and 97 non-students). Results indicated that participants who reported spending greater time on the Internet showed significantly higher trust ratings on several components than those who reported spending less time on the Internet. Participants had difficulty discriminating between actual and fictitious quality seals and organization/domain names, with several fictitious ones judged as or more trustworthy than actual ones.
Histone deacetylase inhibitors and cell proliferation in pea root meristems

The histone deacetylase (HDA) inhibitors, trichostatin A (TSA) and HC toxin halt mitosis in cultured root meristems of Pisnum sativum, while the anti-protozoan HDA inhibitor apicidin is ineffective. Two-dimensional PAGE of proteins from root meristems exposed to TSA and HC toxin did not show significant differences compared to controls, although a previously tested HDA inhibitor, butyrate, exhibited dramatic variations in its protein profile. Northern analysis of butyrate- and TSA-treated root meristems indicated that non-proliferating cells are expressing significant amounts of transcripts of the known cell proliferation associated genes: histone H2A, MAP kinase, cycA2:1 and cdc2. Western analysis reveals the presence of hyperacetylated nuclear proteins in HDA-inhibitor treated cells. These results suggest that the HDA inhibitors, butyrate and TSA, halt mitosis without down-regulating genes that typically have low or nonexistent expression levels in non-dividing cells.
The Evolution of Plug-In Electric Vehicle-Grid Interactions

Over the past decade key technologies have progressed so that mass-market viable plug-in electric vehicles (PEVs) are now set to reach the first of many major vehicle markets by 2011. PEV-grid interactions comprise a mix of industries that have not interacted closely in the past. A number of these commercial participants have utilized the same basic business model for nearly a century. The various participants include vehicle manufacturers, utilities, and supplier firms who have radically different business models, regulatory and legal environments, geographical scope, and technical capabilities. This paper will provide a survey of PEV technology trends and other factors. From an analysis of these factors this paper synthesizes and provides a likely scenario for PEV-grid interaction over the next decade.
Potential Well Escape of an Eccentric Disk

This paper investigates the dynamic behavior of an eccentric disk rolling on a curve of arbitrary shape and then on a curve defined as a cubic function. Comparisons are made to a disk with no eccentricity and the related point mass approximation. The curve is subject to base excitation, and the system is considered from the perspective of a potential well problem where escape is possible on one side. The equations of motion are derived using a roll-without-slip constraint, and the behavior is investigated by means of simulated frequency and amplitude parameter sweeps and by considering the basins of attraction when initial conditions or forcing parameters are varied.Copyright © 2012 by ASME
General Principles of Transport Law and the Rotterdam Rules

Now that the United Nations has adopted the Convention on Contracts for the International Carriage of Goods Wholly or Partly by Sea, popularly known as the Rotterdam Rules, and over twenty nations have signed the Convention, the ratification process is well underway.
The Influence of a Model's Reinforcement Contingency and Affective Response on Children's Perceptions of the Model.

Abstract Following their observation of a videotaped model, boys and girls were asked to rate various characteristics of that model. In each of two experiments, the subjects were 90 primary grade children. The model's reinforcement (reward, punishment, or no consequences) and affective response (positive, neutral, or negative) constituted the independent variables. In both experiments, children who observed an affectively neutral model receive punishment, perceived his affective state as more negative than children who observed this model receive reward or no consequences. The converse attribution (i.e., inferring consequences based on depicted model affect) did not obtain. Also, data from both experiments supported the conclusions that (a) the punished model was less attractive than no-consequences and rewarded models, and (b) the model was perceived as less competent when he demonstrated negative affect or received punishment.
Bone Health and Associated Metabolic Complications in Neuromuscular Diseases

This article reviews the recent literature regarding bone health as it relates to the patient living with neuromuscular disease (NMD). Studies defining the scope of bone-related disease in NMD are scant. The available evidence is discussed, focusing on abnormal calcium metabolism, increased fracture risk, and the prevalence of both scoliosis and hypovitaminosis D in Duchenne muscular dystrophy, amyotrophic lateral sclerosis, and spinal muscular atrophy. Future directions are discussed, including the urgent need for studies both to determine the nature and extent of poor bone health, and to evaluate the therapeutic effect of available osteoporosis treatments in patients with NMD.
Using Sociocultural Theory to Understand the Relationship between Teacher Change and a Science-based Professional Education Program

This paper focuses on a model of teacher change based on a study of a science discipline-based professional education program and on an understanding of teacher change in terms of an agency| structure dialectic. Professional education programs should expand teachers' capacity to act in a range of fields. Conducted over one year, this study used socio-cultural theory to examine the role of cultural schema and resources in the enactment of new pedagogical structures by two teachers who demonstrated widely variable responses to their experience of a professional chemistry education program. Hermeneutic and phenomenological methods of study supported the examination of teacher actions and narratives as sources of data. The analyses of these data sources resulted in greater understanding of the relationship between schema, resources and structure and the relationship between structure and teacher agency. Structures are dynamic and if a teacher uses a resource such as an inquiry-based instruction protocol without the attendant cultural schema such as the value of questioning then the structure that is implemented will be different from that the teacher experienced in the professional education program. This understanding supported an explanation of teacher change in terms of teacher agency that constituted our learning from the study and resulted in changes to aspects of the professional education program.
Tunable Dielectric Properties of BST Thin Films for RF/MW Passive Components

Heteroepitaxial Ba 0.6 Sr 0.4 TiO 3 films were deposited on (100) LaAlO 3 and (100) MgO substrates via pulsed laser deposition. Film thickness varied from 22 nm to 1.15 w m. All films were examined with x-ray diffraction and cross-section FESEM to determine both epitaxy and thickness, and stoichiometry was confirmed with RBS measurements. Microwave dielectric measurements were carried out in the range of 1-20 GHz, using an interdigitated electrode array. The state of strain in the films as a function of thickness and substrate type was correlated with the observed capacitive tunability. The tunability for both film series was shown to exhibit markedly different behavior depending on the type of strain, compressive or tensile. Maximum dielectric tunabilities of ∼ 65% were achieved for the thickest films in both film sets, however the tunability of the thinnest films were much higher for the films grown on MgO.
Studies of peptide conformation: backbone folding of tetrapeptide derivatives in methanol and water.

Derivatives of tetrapeptide sequences considered likely to form β-turns were investigated by the study of their proton magnetic resonances in methanol and in water. Differential broadening of N—H resonances by an added nitroxyl was used to indicate the presence of the sequestered N—H proton expected in β-turn conformations. Transfer of magnetic saturation from solvent water protons to N—H protons was also examined. The evidence is consistent with significant contributions by β-turn-like backbones to the conformational averages in methanol of the sequences Gly-L-Pro-D-Val-Gly, D(or L)-Val-L-Pro-Gly-Gly, and Gly-L-Pro-L-Asn-Gly, but not the sequence Gly-D-Ala-L-Val-Gly. It is suggested that a Type I turn, Likely in Gly-L-Pro-L-Asn-Gly derivatives, is characterized by sequestered N—H protons of both the third and fourth residues. For all of the peptide derivatives, save possibly Ac-L-Val-L-Pro-Gly-Gly-NHNH2, contributions from folded structures in water are not detectable by line-broadening experiments. However, the transfer of saturation experiments may be interpreted as indicating some degree of chain folding in water.
Response characteristics of single units in the inferior colliculus of mustache bats to sinusoidally frequency modulated signals

1. The discharge properties of single units in the inferior colliculus of the mustache bat,Pteronotus parnellii, were evaluated with tone bursts and sinusoidal frequency modulated (SFM) stimuli. The SFM signals were designed to mimic the modulation patterns imposed upon the echoes reflected from the beating wings of flying insects. 2. Two groups of neurons were distinguished on the basis of their best frequencies (BFs). The first group was called the filter neurons and had BFs between 60–64 kHz. These neurons are involved in processing the constant frequency component of the bat's echolocation calls. The second group, or non-filter, neurons, had BFs below 60 kHz, or above 64 kHz. 3. Ninety percent of the filter neurons and 80% of the non-filter neurons responded to SFM signals with discharges that were phase locked to the modulation waveform. However, the two groups of neurons differed markedly in their sensitivity to very low modulation depths. The majority of filter neurons displayed locked discharges to SFM depths as low as ±50 Hz, and some even locked to depths of ±10 Hz, while only two non-filter units (out of 71 tested) locked to depths of ±50 Hz, and none locked to ±10 Hz. 4. Most filter units displayed a marked selectivity, or tuning, for particular modulation depths, rates, and signal intensities. In these tuned or selective units, locking could be evoked only over a fairly narrow range of depths, rates, and/or intensities. When SFM parameters outside of the neuron's tuned range were presented, only phasic-on or on-off discharges could be evoked. 5. The influence of the SFM carrier frequency was also evaluated in filter units. In some units, the particular carrier frequency used was not critical for evoking locked discharges so long as the signal encroached upon the unit's tuning curve. In the majority of filter units, however, there was a marked asymmetry in that some carrier frequencies were much more effective in evoking locked discharges than were other frequencies. In some asymmetric units, frequencies below the BF were most effective and in other units carrier frequencies above the BF were most effective. 6. We examined the inhibitory surround patterns in 15 filter units under the assumption that a predominant inhibitory flank on one or another side of the BF might account for the asymmetry in the effective SFM carrier frequencies. Detailed analyses in eight filter neurons yielded no relationship between the position of the inhibitory side bands and the asymmetry of SFM frequencies evoking locked discharges.
Recognition memory as influenced by differential attention to semantic and acoustic properties of words

Lists of 264 words were studied by 75 Ss. The Ss were divided into three groups instructed to remember either meaning or sound or both meaning and sound of the study words. During recognition, S was required to indicate which word of each test pair had been presented earlier. The incorrect alternative for each test pair was a homophone, synonym, or a word unrelated to the correct choice. Recognition increased as instructional emphasis on remembering word meaning increased. Overall recognition was best when the incorrect choice was unrelated to the study word, and worst when the incorrect choice was a synonym of the study word. The high performance levels obtained under some conditions suggest that word features other than semantic and plume tic information are important for word recognition.
Potentiation of TRPM7 Inward Currents by Protons

TRPM7 is unique in being both an ion channel and a protein kinase. It conducts a large outward current at +100 mV but a small inward current at voltages ranging from −100 to −40 mV under physiological ionic conditions. Here we show that the small inward current of TRPM7 was dramatically enhanced by a decrease in extracellular pH, with an ∼10-fold increase at pH 4.0 and 1–2-fold increase at pH 6.0. Several lines of evidence suggest that protons enhance TRPM7 inward currents by competing with Ca2+ and Mg2+ for binding sites, thereby releasing blockade of divalent cations on inward monovalent currents. First, extracellular protons significantly increased monovalent cation permeability. Second, higher proton concentrations were required to induce 50% of maximal increase in TRPM7 currents when the external Ca2+ and Mg2+ concentrations were increased. Third, the apparent affinity for Ca2+ and Mg2+ was significantly diminished at elevated external H+ concentrations. Fourth, the anomalous-mole fraction behavior of H+ permeation further suggests that protons compete with divalent cations for binding sites in the TRPM7 pore. Taken together, it appears that at physiological pH (7.4), Ca2+ and Mg2+ bind to TRPM7 and inhibit the monovalent cationic currents; whereas at high H+ concentrations, the affinity of TRPM7 for Ca2+ and Mg2+ is decreased, thereby allowing monovalent cations to pass through TRPM7. Furthermore, we showed that the endogenous TRPM7-like current, which is known as Mg2+-inhibitable cation current (MIC) or Mg nucleotide–regulated metal ion current (MagNuM) in rat basophilic leukemia (RBL) cells was also significantly potentiated by acidic pH, suggesting that MIC/MagNuM is encoded by TRPM7. The pH sensitivity represents a novel feature of TRPM7 and implies that TRPM7 may play a role under acidic pathological conditions.
Pseudomonas syringae as a microbial antagonist of Ceratocystis ulmi in the apoplast of American elm

Isolates of Pseudomonas syringae are antagonistic to Ceratocystis ulmi, the causal agent of Dutch elm disease. P. syringae grows and produces antimycotics on expressed elm sap and on an extract of elm wood. When specific isolates of P. syringae, designated M27m and M323m, were introduced into the apoplast of greenhouse-grown elm seedlings, they established themselves without significant phytotoxicity and suppressed the development of vascular discolouration due to Dutch elm disease.
Imaging of the aging brain. Part II. Pathologic conditions.

The most common pathologic disorders in the elderly result in dementia, movement disorders, and/or focal neurologic deficit. Neuroimaging, particularly magnetic resonance (MR), provides a unique window into the diagnosis and understanding of such diseases. The most common cause of dementing illness is Alzheimer disease (enlarged cerebrospinal fluid spaces, focal medial temporal lobe abnormal signal intensity, cortical iron). Since the initiation of MR imaging, important questions are being asked about the role of white matter disease (signal hyperintensities) in primary degenerative dementia and the nosology of vascular dementia. Parkinsonian disorders are characterized by generalized brain atrophy and dopaminergic site (e.g., putamen, pars compacta of the substantia nigra) iron or pigmentary accumulation best visualized in disease that responds poorly to dopamine replacement therapy. A key role of imaging in the elderly is the noninvasive exclusion of mass lesion (e.g., hematoma, neoplasm). MR imaging is...
A Coupled Transport and Solid Mechanics Formulation for Modeling Oxidation and Decomposition in a Uranium Hydride Bed

Modeling of reacting flows in porous media has become particularly important with the increased interest in hydrogen solid-storage beds. It is important for design applications to have an accurate, but relatively simple model for system analysis. We are interested in simulating the reaction of uranium hydride and oxygen gas in a hydrogen storage bed using multiphysics finite element modeling. Our model considers chemical reactions, heat transport, and mass transport within a hydride bed. Previously, the time-varying permeability and porosity were considered uniform. This led to discrepancies between the simulated results and experimental measurements. In this work, we account for the effects of non-uniform changes in permeability and porosity due to phase and thermal expansion. These expansions result in mechanical stresses which lead to bed deformation. To describe this, we develop a simplified solid mechanics model for the local variation of permeability and porosity as a function of the local bed deformation. We find that, by using this solid mechanics model, we improve the agreement between our reacting bed model and the experimental data.Copyright © 2012 by ASME
In Situ FT-IR Studies of Langmuir-Blodgett Monolayers

The liquid-expanded (LE) to liquid condensed (LC) phase transition of monomolecular films of 1,2-dipalmitpol-5-sn-glycero-3-phosphocholine (DPPC) on water substrates was examined via single reflectance FT-IR Spectroscopy in the CH2 stretching region. A continuous decrease in frequency observed in these bands as a function of decreasing molecular area indicates that the DPPC monolayer transition involves a conformational change in the hydrocarbon chains and is biphasic in nature.
The contribution of dynamic changes in photosynthesis to shade tolerance of two conifer species

a range of canopy openness up to 30%. We measured variation in photosynthetic capacity over the growing season and within days and estimated photosynthesis induction in relation to ambient light. Three components of shade tolerance are associated with variation in light climate: (i) Total light on the floor of an 88-year stand of naturally regenerated T. heterophylla was greater on overcast than clear days. Light on overcast days varied throughout the day sometimes with a cyclical pattern. (ii) Photosynthetic capacity, Amax, varied both through the growing season and within days. Amax was generally greater in the latter part of the growing season, being limited by temperature and stomatal conductance, gs, at times during the early part. Saplings in more shaded areas had lower Amax and in the latter part of the growing season Amax was found to decline from mid-afternoon. (iii) Two patterns of photosynthesis induction to increased light were found. In a mean ambient light of 139 µmol m −2 s −1 , induction had a curvilinear response to a step increase in light with a mean time constant, τ, of 112.3 s. In a mean ambient light of 74 µmol m −2 s −1 , induction had a two-part increase: one with τ1 of 11.3 s and the other with τ2 of 184.0 s. These are the smallest published values of τ to date. (iv) Both variation in photosynthetic capacity and induction are components of shade tolerance where light varies over time. Amax acclimates to seasonal and diurnal changes in light and varies between microenvironments. The rapid induction processes can cause a rapid response of photosynthesis to changes in diffuse or direct light.
Tricuspid valve magnetic resonance imaging phase contrast velocity-encoded flow quantification for follow up of tetralogy of Fallot

Our purpose was to identify E- and A-wave flow patterns across the tricuspid valve in tetralogy of Fallot (TOF) patients following repair using magnetic resonance imaging phase contrast velocity-encoded flow quantification and to correlate them with measurements of right ventricle enlargement. The study included 33 children following TOF repair who had MRI examinations that included cine imaging to quantify ventricle size and function and flow analysis across the atria-ventricular valves to evaluate ventricle in-flow patterns. The E:A ratio was calculated for each patient and the population separated into α (E:A ratio ≥ 1.4) and β (E:A ratio < 1.4) groups. Significant association was present between the β group and right ventricle end diastolic volume index ≥140 ml/m2 (P = 0.046), right ventricle end systolic volume index ≥70 ml/m2 (P = 0.02), and end diastolic volume right ventricle to left ventricle ≥ 2.0 (P = 0.003). A reduction in the E:A wave ratio across the tricuspid valve is associated with right ventricle diastolic dysfunction and correlated well in our study with right ventricle enlargement. This may be a useful criterion for determining the timing of valved pulmonary conduit surgery in children following TOF repair.
Dynamics of bubbles near a rigid surface subjected to a lithotripter shock wave. Part 2. Reflected shock intensifies non-spherical cavitation collapse

In this paper we use the boundary integral method to model the non-spherical collapse of bubbles excited by lithotripter shock waves near a rigid boundary. The waves we consider are representative of those developed by shock wave lithotripsy or shock wave therapy devices, and the rigid boundaries we consider are representative of kidney stones and reflective bony tissue. This study differs from previous studies in that we account for the reflection of the incident wave and also the asymmetry of the collapse caused by the presence of the rigid surface. The presence of the boundary causes interference between reflected and incident waves. Quantities such as kinetic energy, Kelvin impulse and centroid translation are calculated in order to illuminate the physics of the collapse process. The main finding is that the dynamics of the bubble collapse depend strongly on the distance of the bubble relative to the wall when reflection is taken into account, but much less so when reflection is omitted from the model. The reflection enhances the expansion and subsequent collapse of bubbles located near the boundary owing to constructive interference between incident and reflected waves; however, further from the boundary, the dynamics of collapse are suppressed owing to destructive interference of these two waves. This result holds regardless of the initial radius of the bubble or its initial state at the time of impact with the lithotripter shock wave. Also, the work done by the lithotripter shock wave on the bubble is shown to predict strongly the maximum bubble volume regardless of the standoff distance and the presence or absence of reflection; furthermore, allowing for non-sphericity, these predictions match almost exactly those of a previously developed spherical model.
John Robert Borchert, 1918–2001

During a Geography Department faculty meeting in the 1980s, we were discussing the perennial question of whether a course on the development of geographic thought and practice should be required of...
A comparison of coverage-based and distribution-based techniques for filtering and prioritizing test cases

This paper presents an empirical comparison of four different techniques for filtering large test suites: test suite minimization, prioritization by additional coverage, cluster filtering with one-per-cluster sampling, and failure pursuit sampling. The first two techniques are based on selecting subsets that maximize code coverage as quickly as possible, while the latter two are based on analyzing the distribution of the tests' execution profiles. These techniques were compared with data sets obtained from three large subject programs: the GCC, Jikes, and javac compilers. The results indicate that distribution-based techniques can be as efficient or more efficient for revealing defects than coverage-based techniques, but that the two kinds of techniques are also complementary in the sense that they find different defects. Accordingly, some simple combinations of these techniques were evaluated for use in test case prioritization. The results indicate that these techniques can create more efficient prioritizations than those generated using prioritization by additional coverage.
A decision-tree-based symbolic rule induction system for text categorization

We present a decision-tree-based symbolic rule induction system for categorizing text documents automatically. Our method for rule induction involves the novel combination of (1) a fast decision tree induction algorithm especially suited to text data and (2) a new method for converting a decision tree to a rule set that is simplified, but still logically equivalent to, the original tree. We report experimental results on the use of this system on some practical problems.
Slew-rate controlled 800Mbps transmitter in 65nm CMOS

A slew-rate controlled, 800Mbps voltage mode differential transmitter is presented here. An add-on, capacitive charge transfer based scheme is used to control output rise/fall times. The transmitter, designed and fabricated in a 65nm CMOS technology, occupies an active area of 0.02mm2 and consumes 2.7mW. Of this, the add-on slew-rate control occupies an area of 0.0027mm2, and consumes 0.5mW.
Brazilians Working with Americans: Cultural Case Studies by KELM, ORLANDO R., & MARY E. RISNER.

The article reviews the book "Brazilians Working With Americans: Cultural Case Studies," by Orlando R. Kelm and Mary E. Risner.