cssi/SciSciGPT-SciSciNet huggingface dataset:
Direct coupling of a carbon nanotube membrane to a mass spectrometer: Contrasting nanotube and capillary tube introduction systems

Abstract A carbon nanotube membrane was directly coupled to the inlet system of a mass spectrometer to evaluate its use as a novel potentially tunable membrane inlet system. Carbon nanotubes for the membrane were synthesized using the template method. Chemical vapor deposition of a hydrocarbon precursor produced nearly graphitic carbon nanotubes within the pores of an anodic aluminum oxide membrane. The selectivity of the carbon nanotube membrane was compared to that of a capillary tube. Relative to the capillary tube, the carbon nanotube membrane was preferentially transmissive to methane. Conductance of gas mixtures exhibited different dependencies on total pressure in carbon nanotube and capillary tube introduction systems. In carbon nanotubes, conductance decreased with increasing total pressure, and the extent of the decrease became progressively smaller between methane and carbon dioxide (CH 4 > N 2 > O 2 > Ar > CO 2 ). In the capillary tube introduction system, conductance decreased substantially only for nitrogen. The capillary tube conductance for methane was nearly independent of total pressure, and conductance increased progressively between O 2 , Ar and CO 2 .
Probing the interaction between KCNE2 and KCNQ1 in their transmembrane regions.

KCNE1-KCNE5 are single membrane-spanning proteins that associate with voltage-gated potassium channels to diversify their function. Other than the KCNQ1/KCNE1 complex, little is known about how KCNE proteins work. We focus on KCNE2, which associates with KCNQ1 to form K channels critical for gastric acid secretion in parietal cells. We use cysteine (Cys)-scanning mutagenesis to probe the functional role of residues along the KCNE2 transmembrane domain (TMD) in modulating KCNQ1 function. There is an α-helical periodicity in how Cys substitutions along the KCNE2 TMD perturb KCNQ1 pore conductance/ion selectivity. However, positions where Cys substitutions perturb KCNQ1 gating kinetics cluster to the extracellular end and cytoplasmic half of the KCNE2 TMD. This is the first systematic perturbation analysis of a KCNE TMD. We propose that the KCNE2 TMD adopts an α-helical secondary structure with one face making intimate contact with the KCNQ1 pore domain, while the contacts with the KCNQ1 voltage-sensing domain appear more dynamic.
System-level power estimation and optimization

Most work to date on power reduction has focused at the component level, not at the system level. In this paper, we propose a framework for describing the power behavior of system-level designs. The model consists of a set of resources, an environmental workload specification, and a power management policy, which serves as the heart of the system model. We map this model to a simulation-based framework to obtain an estimate of the system's power dissipation. Accompanying this, we propose an algorithm to optimize power management policies. The optimization algorithm can be used in a tight loop with the estimation engine to derive new power-management policy algorithms for a given system-level description. We tested our approach by applying it to a real-life low-power portable design, achieving a power estimation accuracy of /spl sim/10%, and a 23% reduction in power after policy optimization.
Back to the Street: When Media and Opinion Leave Home

To achieve “deliberative democracy,” Gabriel Tarde's formula not only demands the press hold a nation together, but also offers an agenda of issues that serves as a kind of menu for discussions in cafes and salons, which leads, in turn, to more considered opinions, and thus provides the consensual valuations that inform political, economic and aesthetic actions. The elements of the formula consist of press, conversation, opinion, and action. I argue that the long-run effect of the mainstream media—the newspaper, but even more the radio and television— moved politics off the street and into the home, hence the concern over “the narcotizing dysfunction” of the news media. In the era of the Internet, I argue that media—old or new, mass or social—are far from being the whole of the story. It is some combination of these media, plus word of mouth, plus some rather well-known elements of social-movement theory, plus the social psychology of collective behavior that help to explain. But let us not lose sight of ...
Dysphonia in performers: toward a clinical definition of laryngology of the performing voice.

Summary Objectives To identify causes of dysphonia in performers and compare causes and aspects of treatment of dysphonia in performers and nonperformers. Study Design Case-control study. Methods A chart review of all new patients presenting with a chief complaint of dysphonia over a 1-year period was performed. The prevalence of laryngeal disorders was reviewed and differences between performers and nonperformers were analyzed. The odds ratio of the prevalence of each disorder was computed against performer status as a risk factor. Results Four hundred seventy-six new patients complaining of dysphonia presented over 12 months; 74 were vocal performers. The median duration of symptoms in performers was 90 days. Phonotraumatic lesions were significantly more prevalent in performers (63.5% vs 28.6%, P Conclusions Phonotraumatic injury is responsible for the majority of dysphonia in vocal performers, to a significantly greater extent than in nonperformers and requires the implementation of standard therapeutic strategies. Awareness of the specific risks and management needs of the performer is of paramount importance to the practice of laryngology of the performing voice.
Comparisons between Museum and Mass-Produced Art

Mass-produced art is a popular and inexpensive form of art which imitates museum art of the realistic sort, e.g., landscapes. Previous research has indicated that this art is positively evaluated. ...
Phosphorylation of lens‐fiber connexins in lens organ cultures

Lens gap junction proteins, connexins [1], are known to be phosphorylated in vivo. Phosphorylated states of connexins were examined in lens cultures to define in vitro models for the study of the functions of lens connexin phosphorylation in lens biology. In organ and differentiated cell primary cultures, chick lens-fiber connexins, connexin45.6 and connexin56, were labeled with [32P]orthophosphate. Pulse-chase experiments of lens organ cultures with [35S]methionine demonstrated that connexin45.6 and connexin56 were properly processed into the phosphorylated forms observed in vivo. However, in lens cell primary cultures, both connexins had short half-lives, and connexin56 was degraded before it was phosphorylated into the form which showed the largest mobility shift. The data suggested that the phosphorylation patterns of connexins in lens organ cultures were similar to in vivo connexin phosphorylation, while primary cultures revealed abnormal rates of protein turnover and incomplete phosphorylation. Treatment of lens organ cultures with protein kinase inhibitors indicated that protein kinase C was involved in the phosphorylation of connexin45.6 and connexin56. Comparison of the phosphopeptide patterns by two-dimensional mapping suggested that protein kinase C was involved in the phosphorylation of connexin45.6 and that it phosphorylated the C-terminus of connexin45.6 in vitro.
Buoyant convection resulting from dissolution and permeability growth in vertical limestone fractures

[1] Upward flow through vertical fractures in limestone formations under a geothermal gradient favors dissolution and permeability growth. We investigate the transition from conductive and forced convective regimes to instability and buoyant convection as a result of permeability growth. The onset time for instability and roll height at onset depend on the initial aperture and driving pressure. A modified Rayleigh number criterion is proposed, which provides a unified interpretation of the instability across a wide range of initial aperture and driving pressure. Interaction between buoyant convection and aperture alteration leads to narrow upward flow paths supporting dissolution and precipitation in surrounding downward flow regions.
Sensitive Thermal Analysis Establishing Formation of the Incongruently Melting Compound LiNaCO 3

Sensitive Thermal Analysis Establishing Formation of the Incongruently Melting Compound LiNaCO3
Self-Healing Technology for Compressor and Turbine Blades

The problem of cracking in steam turbines and compressor blades is one of the major problems associated with their design. Not only in these areas, but many other parts are suffering from the same problem of cracking due to excess stress, fatigue and high temperatures. One of the recent solutions to this is the use of specialized alloys, ceramics and metal matrix composites with improved high temperature strength and fatigue limits, but these materials will also suffer from cracking. Another potential method of improving the fatigue life of steam turbine and compressor blades is through the use of self-healing metals. There has been a recent interest in making self-healing metal composites that heal any cracks with little or no human interaction. One of the ways to achieve this is to send a healing agent (generally a low melting alloy or uncured resin) through hollow passages made in the matrix. When a crack appears, the healing agent flows into the crack, solidifies and closes the crack, effectively healing it. Recently, researchers at UW-Milwaukee have extended the concept of self-healing to metals, and have synthesized self-healing aluminum and solder alloys. This method may be used for the blades of steam turbines and compressors. The hollow passages can be made in a similar method that cooling passages of the gas turbine blades are made. Proper material choice will result in good bonding between the healing agent and the walls of a crack. This study deals with the advantages, ease of use and other considerations for this method to be used in practice. The main problems that need to be over come are materials selection, loss of strength due to addition of hollow channels, and the need to develop methods to initiate healing by flow of the healing agent into a crack. Plausible solutions to these are also discussed.Copyright © 2009 by ASME
Russell receives 2003 John Adam Fleming medal

Christopher T Russell was awarded the Fleming Medal at the AGU Fall Meeting Honors Ceremony, which was held on 10 December 2003, in San Francisco, California. The medal honors “original research and technical leadership in geomagnetism, atmospheric electricity, aeronomy, space physics, and related sciences.”
Combinatorial therapy using negative pressure and varying lithium dosage for accelerated wound healing.

Abstract In this work, we investigated the effects of negative pressure, applied using a pump designed for Negative Pressure Wound Therapy (NPWT), on the process of wound healing in vitro via initiation of the Wnt signaling pathway. Results indicate that negative pressure enhanced Wnt signaling and migration into a simulated wound in vitro in NIH-3T3 murine fibroblast cells. Increasing doses of lithium (upto 15 mM) increased basal Wnt signaling and enhanced cell migration into the simulated wound site. A combination of negative pressure and increased doses of lithium synergistically increased Wnt signaling and demonstrated further enhanced cell migration into simulated wound sites, with maximal filling of the simulated wound observed at lithium concentrations of at least 10 mM.
Anaerobic metabolism and nuclear binding of the carcinogen 2-amino-4-(5-nitro-2-furyl)thiazole (ANFT)

The anaerobic reductive metabolism of the urinary tract carcinogen 2-amino-4-(5-nitro-2-furyl)-[2-14C]-thiazole ([14C]ANFT) was examined in vitro using rabbit liver and kidney microsomes. The intermediate(s) produced during the reduction binds to tRNA, DNA, and protein. ANFT reduction was inhibited by oxygen, required NADPH and was not inhibited by SKF-525A or allopurinol. No binding to tRNA or DNA was observed if the nucleic acids were added at the end of the incubation. The covalent binding of an ANFT metabolite(s) to nucleic acids and protein was inhibited by the antioxidants vitamin E and butylated hydroxytoluene. The stoichiometry of microsomal reduction shows 3 mol of NADPH were used/mol of ANFT reduced. In inner medullary microsomes, the apparent Km and Vmax were 0.05 mM and 0.92 nmol/mg/min, respectively. Two metabolites from the anaerobic incubation of ANFT were isolated. The metabolites were tentatively identified as 1-(2-amino-4-thiazolyl)-3-cyano-1-propanone and 2-amino-4-(5-hydroxyl-amino-2-furyl)thiazole.
Evaluating performance benefits of head tracking in modern video games

We present a study that investigates user performance benefits of using head tracking in modern video games. We explored four different carefully chosen commercial games with tasks which can potentially benefit from head tracking. For each game, quantitative and qualitative measures were taken to determine if users performed better and learned faster in the experimental group (with head tracking) than in the control group (without head tracking). A game expertise pre-questionnaire was used to classify participants into casual and expert categories to analyze a possible impact on performance differences. Our results indicate that head tracking provided a significant performance benefit for experts in two of the games tested. In addition, our results indicate that head tracking is more enjoyable for slow paced video games and it potentially hurts performance in fast paced modern video games. Reasoning behind our results is discussed and is the basis for our recommendations to game developers who want to make use of head tracking to enhance game experiences.
The Visual Looming Navigation Cue

Visual looming is related to an increasing projected size of an object on a viewer's retina as the relative distance between the viewer and the object decreases. It is an indication for threat that may be used along with visual fixation to accomplish navigation tasks. This paper defines visual looming as the time derivative of the relative distance (range) between the observer and the object divided by the relative distance itself. It introduces a unified approach to visual looming by showing how visual looming can be calculated from the relative temporal change in the following attributes of a 2D image sequence: (i) image area, (ii) image brightness, (iii) texture density in the image, and (iv) image blur. It is shown that a closed-form unified expression can be adopted in all these methods. Experimental results illustrate how the measured values of looming are related to the actual values. Finally, looming is used in the sense of a threat of collision, along with visual fixation, to navigate in an unknown environment.
The development of three-dimensional current system during a magnetospheric substorm

Abstract It is suggested that the pattern of three-dimensional substorm current circuit varies significantly even during the lifetime of a single substorm. This gives rise to quite complex time variations of the magnetic field at low latitude stations even for relatively isolated substorms. To verify this, three-dimensional current models with time dependent spatial variations are used to simulate one type of complex low-latitude “substorm signature”. It is shown that the utmost care should be exercised in determining different substorm phases on the basis of such a signature. The results indicate also that, in certain longitudes in the evening sector, one should expect distinct differences in characteristics between positive bays observed on the ground and at the synchronous distance.
Unit root and cointegration tests: timeseries versus panel estimates for international health expenditure models

Classical regression estimates of the determinants of the OECD health expenditures are useful for policy formulation and evaluation. However, if the underlying timeseries data are not collectively stationary in levels, the estimated parameters are faulty and can misguide health policy. Until very recently, the crucial stationarity tests were ignored in a large number of studies on international comparisons. Stationarity (ADF, Phillips-Perron, IPS heterogeneous panel) and cointegration (Engle-Granger bivariate, Johansen's multivariate) tests are conducted here using 1960–1997 health expenditures data (1998 CD ROM) of 19 OECD countries. It is found that extending the time series data length affects the order of integration and number of cointegrating vectors. However, it is arguable whether the order of integration decreases or increases as more observations are added for testing. The failure of the Johansen and Engle-Granger cointegration tests for most of the OECD countries cautions policy makers against ...
Sm-Nd systematics of a tonalitic augen gneiss and its constituent minerals from northern Michigan

Abstract The Sm-Nd isotopic system of a tonalitic augen gneiss and its constituent minerals from northern Michigan was disturbed during metamorphism. Sm-Nd zircon ages are lower than the wholerock Sm-Nd model age. However, closely associated pairs of minerals (for example, sphene and biotite or apatite and plagioclase) retain their apparent metamorphic ages. The Sm-Nd model age for the tonalitic augen gneiss of 3919 ± 30 myr , appears to reflect open system behavior during metamorphism. A mineralogically different gneiss from the same location has a Sm-Nd model age of 3520 ± 70 myr . The two whole rocks differ in their Sm-Nd and Rb-Sr systematics and in their chondrite-normalized rare earth element (REE) patterns. The whole-rock-normalized mineral REE patterns show the contribution of the major and trace minerals to the REE content of the whole rock. The trace minerals contain a significant amount of the total REE.
Thrombin paradox redux

Severe sepsis is both common and deadly. The pathophysiology of sepsis is complex and includes a nonlinear interplay between multiple cell types and soluble mediators.[1][1],[2][2] Over the past decade, enormous resources have been expended on sepsis trials, with more than 10 000 patients enrolled
N(+)-N long-range interaction energies and resonance charge exchange

The aerothermodynamic studies of proposed space missions require atmospheric charge-transfer data. N2(+) eigenstate energies are calculated with use of the complete-active-space self-consistent-field method with an extended Gaussian basis set. The N(+)-N charge-exchange cross section, determined from these energies, agrees with merged-beam measurements. This contradicts the previous theoretical conclusion. A simple physical description of the long-range interaction is presented and should expedite future charge-transfer studies.
Carbon tether rigidity as a stereochemical tool directing intramolecular radical cyclizations

Abstract The phenyl group incorporated into a carbon tether provides for the synthesis of 1,5-cyclodecadiynes with 95–100% d,l-diastereoselectivity due to intrinsic conformational constraints and preorganization of the Co2(CO)6-complexed propargyl intermediates.
Maximum partial area rule for phase equilibrium calculations

Eubank and Hall have shown recently that the tangent-line criterion reduces to an equal area construction for the derivative of the total Gibbs energy plotted against composition. This paper presents another criterion along with a thermodynamic proof, the maximum partial area rule (MPAR), which establishes an area on the plot of the derivative of the Gibbs energy with respect to composition which is always a maximum at equilibrium. The method based upon this criterion is especially powerful for complex phase equilibria involving multiple components and phases.
AN EMPIRICAL NOTE ON THE COMPARATIVE MACROECONOMIC EFFECTS OF THE GST IN AUSTRALIA, CANADA AND NEW ZEALAND

Australia, Canada and New Zealand have a multitude of cultural and economic characteristics in common that facilitates interesting comparisons between them. This short note takes advantage of this shared heritage by providing a brief empirical comparison of the macroeconomic effects of the introduction of the goods and services tax in the three countries. We consider summary data on some selected macroeconomic variables, including various neutrality measures, aggregate consumer price changes, economic growth effects, tax yield effects, and current account balance effects. It is concluded that not only was the GST highly successful in raising tax revenues, but it was also significant in terms of growth effects, price effects, current account effects, and the effect on the budget balance.
Cardiac output, at rest and during exercise, before and during myocardial ischemia, reperfusion, and infarction in conscious mice

Multiple systems and regulatory strategies interact to control cardiac homeostasis. In fact, regulated systems, feedback controls, and redundant control mechanisms dominate in whole animals. Accordingly, molecular and cellular tools and techniques must be utilized in complex models with multiple systems and regulatory strategies to fully appreciate the physiological context. Currently, these techniques are mainly performed under conditions remote from the normal in vivo condition; thus, the extrapolation of molecular changes to the in vivo situation and the facilitation of translational aspect of the findings are limited. A major obstacle has been the reliance on preparations that do not mimic the clinical or physiological situation. This is particularly true regarding measurements of cardiac function in mice. To address these concerns, we used a permanently implanted Doppler ultrasonic flow probe on the ascending aorta and coronary artery occluder for repeated measurements of ascending aortic blood flow (cardiac output) in conscious mice, at rest and during exercise, before and during coronary artery occlusion/reperfusion and infarction. The conscious mouse model permits detailed monitoring of within-animal changes in cardiac function during myocardial ischemia, reperfusion, and infarction in an intact, complex model free of the confounding influences of anesthetics, surgical trauma, and restraint stress. Results from this study suggest that previous protocols may have overestimated resting baseline values and underestimated cardiac output reserve. Using these procedures in currently available spontaneous or engineered mouse mutants has the potential to be of major importance for advancing the concepts and methods that drive cardiovascular research.
QoS provisioning and queue management in mobile ad hoc networks

An analytical traffic model and three queue management schemes are developed for a heterogeneous multihop mobile ad hoc network (MANET). The traffic model is built by a two-dimensional Markov process and some important performance metrics are developed. Based on the obtained metrics, three queue management schemes with QoS (quality of service) provisioning are developed for dynamic traffic conditions. Performance comparisons among the three schemes are presented
Interactive image fusion in distributed visualization environments

This paper presents an immediate-mode, integrated approach to image fusion and visualization of multi-band satellite data, drawing from the computational resources of networked, high-resolution, tiled display environments. The presented workflow enables researchers to intuitively and interactively experiment with all tunable parameters, exposed through external devices such as MIDI controllers, to rapidly modify the image processing pipeline and resulting visuals. This presented approach demonstrates significant savings across a set of case studies, with respect to overall data footprint, processing and analysis time complexity.
M-ary hyper phase-shift keying over non-linear satellite channels

Forward error correction (FEC) coding in conjunction with M-ary hyper phase-shift keying (MHPSK) is considered in order to improve the robustness of a high spectral efficiency, non-linear satellite communications link. MHPSK is a spectrally efficient modulation technique that uses four orthonormal basis functions to increase the Euclidean distance between different symbols in the signal space. The use of four orthonormal basis functions provides an advantage over traditional spectrally efficient modulation techniques such as M-ary phase-shift keying (MPSK) and M-ary quadrature amplitude modulation (MQAM) that only possess two degrees of freedom. MHPSK offers an improvement in probability of bit error performance over other spectrally efficient modulation techniques for the same average energy per bit-to-noise power spectral density ratio and the same spectral efficiency. As a result, MHPSK offers a novel way to improve both throughput and reduce power requirements using easy to generate waveforms. MHPSK and two-subcarrier orthogonal frequency division multiplexing (OFDM) with 8-PSK or 8-QAM on each subcarrier are compared in terms of the effect of peak-to-average power ratio and required amplifier backoff on the probability of bit error. In this paper, long block length Reed Solomon (RS) codes are used to encode information symbols which are then transmitted with MHPSK. Additionally, a comparison is made with two-subcarrier OFDM that uses 8-PSK or 8-QAM on each subcarrier and utilizing the Digital Video Broadcast (DVB) standard rate 0.9 low density parity check (LDPC) code commonly employed in non-linear satellite communications. As such, MHPSK and two-subcarrier OFDM with 8-QAM or 8-PSK on each subcarrier are compared in terms of probability of bit error, peak-to-average power ratio, amplifier backoff, and bandwidth efficiency using long forward error correction code block lengths.
Food and drug reward: overlapping circuits in human obesity and addiction.

Both drug addiction and obesity can be defined as disorders in which the saliency value of one type of reward (drugs and food, respectively) becomes abnormally enhanced relative to, and at the expense of others. This model is consistent with the fact that both drugs and food have powerful reinforcing effects—partly mediated by dopamine increases in the limbic system—that, under certain circumstances or in vulnerable individuals, could overwhelm the brain’s homeostatic control mechanisms. Such parallels have generated significant interest in understanding the shared vulnerabilities and trajectories between addiction and obesity. Now, brain imaging discoveries have started to uncover common features between these two conditions and to delineate some of the overlapping brain circuits whose dysfunctions may explain stereotypic and related behavioral deficits in human subjects. These results suggest that both obese and drug-addicted individuals suffer from impairments in dopaminergic pathways that regulate neuronal systems associated not only with reward sensitivity and incentive motivation, but also with conditioning (memory/learning), impulse control (behavioural inhibition), stress reactivity, and interoceptive awareness. Here, we integrate findings predominantly derived from positron emission tomography that shed light on the role of dopamine in drug addiction and in obesity, and propose an updated working model to help identify treatment strategies that may benefit both of these conditions.
Unruptured intracranial aneurysms conservatively followed with serial CT angiography: could morphology and growth predict rupture?

Background and purpose Despite several landmark studies, the natural history of unruptured intracranial aneurysms (UIA) remains uncertain. Our aim was to identify or confirm factors predictive of rupture of UIA being observed conservatively with serial CT angiography (CTA) in a North American patient population. Methods We performed a retrospective review of patients with UIA being followed with serial CTA studies from 1999 to 2010. The following features for each aneurysm were cataloged from the official radiologic reports and CTA images: maximum diameter, growth between follow-up studies, location, multiplicity, wall calcification, intraluminal thrombus and morphology. Univariate logistic regression analysis of the potential independent risk factors for aneurysm rupture was performed. Statistically significant risk factors from the univariate analysis were then entered into a multivariate logistic regression analysis. Results 152 patients with a total of 180 UIA had at least two CTA studies. Six aneurysms in six different patients ruptured during the CTA follow-up period for an overall rupture rate of 3.3% and an annual rupture rate of 0.97%. All ruptured aneurysms were ≥9 mm. In the univariate analysis, the statistically significant predictors of aneurysm rupture were aneurysm size (p=0.003), aneurysm growth (p Conclusions Aneurysm morphology and interval growth are characteristics predictive of a higher risk of subsequent rupture during conservative CTA follow-up.
Low complexity optimal joint detection for oversaturated multiple access communications

Optimal joint detection for interfering (nonorthogonal) users in a multiple access communication system has, in general, a computational complexity that is exponential in the number of users. For this reason, optimal joint detection has been thought to be impractical for large numbers of users. A number of suboptimal low-complexity joint detectors have been proposed for direct sequence spread spectrum user waveforms that have properties suitable for mobile cellular and other systems. There are, however, other systems, such as satellite systems, for which other waveforms may be considered. This paper shows that there are user signature set selections that enable optimal joint detection that is extremely low in complexity. When a hierarchical cross-correlation structure is imposed on the user waveforms, optimal detection can be achieved with a tree-structured receiver having complexity that is, in typical cases, a low-order-polynomial in the number of users. This is a huge savings over the exponential complexity needed for the optimal detection of general signals. Previous work has shown that a hierarchically structured signal set can achieve oversaturation (more users than dimensions) with no growth in the required signal-to-noise ratio. The proposed tree detector achieves low-complexity optimal joint detection even in this oversaturated case.
Nanoimaging: Methods and Protocols

A.A. Sousa and M.J. Kruhlak, eds. New York, NY: Humana Press-Springer, 2013, 510 pages, $159 A common goal in biology is to dissect the astonishing complexity of the cellular molecular machinery, seeking to understand how individual components of this machinery assemble to form higher-order
Greek Mythology: Poetics, Pragmatics and Fiction

Reviewed Medium: book Authors: Claude Calame Year: 2009 Pages: 288 Publisher: Cambridge University Press ISBN: 9780521888585 (hard cover).
Understanding the characteristics of US meat and poultry recalls: 1994-2002

The characteristics of US meat and poultry recalls between 1994 and 2002 are examined and the public health implications of these trends highlighted. Most recalls involve the most serious health consequences, including Class I and biological hazards. Numbers of recalls as well as the total amount in pounds have continually increased since 1997. This may be explained by improving inspection methods for detecting microbial pathogens, greater consumer awareness, and/or better surveillance of foodborne illnesses. To guarantee public health, it is important that problems are discovered as early as possible and all affected products are removed from the market.
Essential role of grim-led programmed cell death for the establishment of corazonin-producing peptidergic nervous system during embryogenesis and metamorphosis in Drosophila melanogaster

In Drosophila melanogaster, combinatorial activities of four death genes, head involution defective (hid), reaper (rpr), grim, and sickle (skl), have been known to play crucial roles in the developmentally regulated programmed cell death (PCD) of various tissues. However, different expression patterns of the death genes also suggest distinct functions played by each. During early metamorphosis, a great number of larval neurons unfit for adult life style are removed by PCD. Among them are eight pairs of corazonin-expressing larval peptidergic neurons in the ventral nerve cord (vCrz). To reveal death genes responsible for the PCD of vCrz neurons, we examined extant and recently available mutations as well as RNA interference that disrupt functions of single or multiple death genes. We found grim as a chief proapoptotic gene and skl and rpr as minor ones. The function of grim is also required for PCD of the mitotic sibling cells of the vCrz neuronal precursors (EW3-sib) during embryonic neurogenesis. An intergenic region between grim and rpr, which, it has been suggested, may enhance expression of three death genes in embryonic neuroblasts, appears to play a role for the vCrz PCD, but not for the EW3-sib cell death. The death of vCrz neurons and EW3-sib is triggered by ecdysone and the Notch signaling pathway, respectively, suggesting distinct regulatory mechanisms of grim expression in a cell- and developmental stage-specific manner.
Searches for invisible axions

The axion, a hypothetical elementary particle, emerged from a compelling solution to the Strong-CP problem in QCD. Subsequently, the axion was recognized to be a good Cold Dark Matter candidate. Although dark matter axions have only feeble couplings to matter and radiation, extremely sensitive searches are underway around the world. We review the state of experiments searching for the axion through its coupling to photons. Besides answering an outstanding question in particle physics, the discovery of dark matter axions may provide a detailed history of the formation of our Milky Way galaxy through the structure of the axion signal. ( 2000 Elsevier Science B.V. All rights reserved.
On the sign of refraction in anisotropic non-magnetic media

The main message of this paper is that refraction of a narrow collimated beam at a negative angle into strongly anisotropic non-magnetic crystals—a phenomenon which was observed in a number of experiments—should not be confused with negative refraction and lacks important physical characteristics of the latter. In particular, it is shown that there is no contradiction between the theory previously developed by one of the authors (in Markel 2008 Opt. Express 16 19152), where it is claimed that negative refraction is impossible, and the experiments mentioned above.
Jugular Vein Rupture Caused by Invasive Squamous Cell Carcinoma

Sonography is a quick, noninvasive way to evaluate superficial masses. Although the information provided can answer important questions about the nature of these masses, the sonographer must have as much clinical information as possible and make sure that each piece of the puzzle fits and makes sense in relation to the known facts. The value of the information contained in the images will not be maximized if sonographers do not have complete clinical information and the ability to integrate the various components to arrive at an appropriate diagnosis. This case illustrates the need to consider all the possibilities, even when, at first glance, the diagnosis seems obvious. (When you hear hoof beats, it is probably a horse...but it may be a zebra!)
Structure/Function Analysis of Xenopus Cryptochromes 1 and 2 Reveals Differential Nuclear Localization Mechanisms and Functional Domains Important for Interaction with and Repression of CLOCK-BMAL1

Circadian rhythms control the temporal arrangement of molecular, physiological, and behavioral processes within an organism and also synchronize these processes with the external environment. A cell autonomous molecular oscillator, consisting of interlocking transcriptional/translational feedback loops, drives the approximately 24-hour duration of these rhythms. The cryptochrome protein (CRY) plays a central part in the negative feedback loop of the molecular clock by translocating to the nucleus and repressing CLOCK and BMAL1, two transcription factors that comprise the positive elements in this cycle. In order to gain insight into the inner workings of this feedback loop, we investigated the structure/function relationships of Xenopus laevis CRY1 (xCRY1) and xCRY2 in cultured cells. The C-terminal tails of both xCRY1 and xCRY2 are sufficient for their nuclear localization but achieve it by different mechanisms. Through the generation and characterization of xCRY/photolyase chimeras, we found that the second half of the photolyase homology region (PHR) of CRY is important for repression through facilitating interaction with BMAL1. Characterization of these functional domains in CRYs will help us to better understand the mechanism of the known roles of CRYs and to elucidate new intricacies of the molecular clock.
Meandering Spiral Waves in the 1,4-Cyclohexanedione Belousov−Zhabotinsky System Catalyzed by Fe[batho(SO3)2]34-/3-

Meandering spiral waves are observed in the 1,4-cyclohexanedione Belousov-Zhabotinsky (CHD-BZ) reaction at very low concentrations (3-35 mM) of the organic substrate. The spiral tips describe hypocycle-like trajectories indicating the presence of two main rotation periods and radii. The ratio of these periods approaches 1 for decreasing concentrations of CHD. In this limit, we find Z-shaped trajectories with approximately two lobes. The use of Fe[batho(SO 3 ) 2 ] 3 4-/3- as the BZ catalyst gives rise to extremely long rotation periods (1000-4000 s), and the tip trajectories span large areas of up to 40 mm 2 . As a result of the absence of gaseous products and the high absorption of the catalyst, this particular system is ideally suited for the investigation of spiral waves in closed, thin-layer systems, such as nonuniformly curved and micropatterned media.
Effect of antimicrobial preservatives on partial protein unfolding and aggregation

One-third of protein formulations are multi-dose. These require antimicrobial preservatives (APs); however, some APs have been shown to cause protein aggregation. Our previous work on a model protein cytochrome c indicated that partial protein unfolding, rather than complete unfolding, triggers aggregation. Here, we examined the relative strength of five commonly used APs on such unfolding and aggregation, and explored whether stabilizing the aggregation ‘hot-spot’ reduces such aggregation. All APs induced protein aggregation in the order m-cresol > phenol > benzyl alcohol > phenoxyethanol > chlorobutanol. All these enhanced the partial protein unfolding that includes a local region which was predicted to be the aggregation ‘hot-spot’. The extent of destabilization correlated with the extent of aggregation. Further, we show that stabilizing the ‘hot-spot’ reduces aggregation induced by all five APs. These results indicate that m-cresol causes the most protein aggregation, whereas chlorobutanol causes the least protein aggregation. The same protein region acts as the ‘hot-spot’ for aggregation induced by different APs, implying that developing strategies to prevent protein aggregation induced by one AP will also work for others. © 2012 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 102:365–376, 2013
Dystonic reaction after ketamine abuse

A 20-year-old man developed an acute dystonic reaction following the self-administration of ketamine. The episode resolved upon treatment with diphenhydramine. Dystonia is an unusual toxic effect of ketamine abuse; potential mechanisms for its occurrence in this instance are discussed.
Moisture-Induced TBC Spallation on Turbine Blade Samples

Delayed failure of TBCs is a widely observed laboratory phenomenon, although many of the early observations went unreported. "The weekend effect" or "DeskTop Spallation" (DTS) is characterized by initial survival of a TBC after accelerated laboratory thermal cycling, then failure by exposure to ambient humidity or water. Once initiated, failure can occur quite dramatically in less than a second. To this end, the water drop test and digital video recordings have become useful techniques in studies at NASA (Smialek, Zhu, Cuy), DECHMA (Rudolphi, Renusch, Schuetze), and CNRS Toulouse/SNECMA (Deneux, Cadoret, Hervier, Monceau). In the present study the results for a commercial turbine blade, with a standard EB-PVD 7YSZ TBC top coat and Pt-aluminide diffusion bond monitored by weight change and visual appearance. Failures were distributed widely over a 5-100 hr time range, depending on temperature. At some opportune times, failure was captured by video recording, documenting the appearance and speed of the moisture-induced spallation process. Failure interfaces exhibited alumina scale grains, decorated with Ta-rich oxide particles, and alumina inclusions as islands and streamers. The phenomenon is thus rooted in moisture-induced delayed spallation (MIDS) of the alumina scale formed on the bond coat. In that regard, many studies show the susceptibility of alumina scales to moisture, as long as high strain energy and a partially exposed interface exist. The latter conditions result from severe cyclic oxidation conditions, which produce a highly stressed and partially damaged scale. In one model, it has been proposed that moisture reacts with aluminum in the bond coat to release hydrogen atoms that 'embrittle' the interface. A negative synergistic effect with interfacial sulfur is also invoked.
Human Hypervirulent Clostridium difficile Strains Exhibit Increased Sporulation as Well as Robust Toxin Production

Toxigenic Clostridium difficile strains produce two toxins (TcdA and TcdB) during the stationary phase of growth and are the leading cause of antibiotic-associated diarrhea. C. difficile isolates of the molecular type NAP1/027/BI have been associated with severe disease and hospital outbreaks worldwide. It has been suggested that these “hypervirulent” strains produce larger amounts of toxin and that a mutation in a putative negative regulator (TcdC) allows toxin production at all growth phases. To rigorously explore this possibility, we conducted a quantitative examination of the toxin production of multiple hypervirulent and nonhypervirulent C. difficile strains. Toxin gene (tcdA and tcdB) and toxin gene regulator (tcdR and tcdC) expression was also monitored. To obtain additional correlates for the hypervirulence phenotype, sporulation kinetics and efficiency were measured. In the exponential phase, low basal levels of tcdA, tcdB, and tcdR expression were evident in both hypervirulent and nonhypervirulent strains, but contrary to previous assumptions, toxin levels were below the detectable thresholds. While hypervirulent strains displayed robust toxin production during the stationary phase of growth, the amounts were not significantly different from those of the nonhypervirulent strains tested; further, total toxin amounts were directly proportional to tcdA, tcdB, and tcdR gene expression. Interestingly, tcdC expression did not diminish in stationary phase, suggesting that TcdC may have a modulatory rather than a strictly repressive role. Comparative genomic analyses of the closely related nonhypervirulent strains VPI 10463 (the highest toxin producer) and 630 (the lowest toxin producer) revealed polymorphisms in the tcdR ribosome binding site and the tcdR-tcdB intergenic region, suggesting that a mechanistic basis for increased toxin production in VPI 10463 could be increased TcdR translation and read-through transcription of the tcdA and tcdB genes. Hypervirulent isolates produced significantly more spores, and did so earlier, than all other isolates. Increased sporulation, potentially in synergy with robust toxin production, may therefore contribute to the widespread disease now associated with hypervirulent C. difficile strains.
Effect of graphic cigarette warnings on smoking intentions in young adults.

Introduction Graphic warnings (GWs) on cigarette packs are widely used internationally and perhaps will be in the US but their impact is not well understood. This study tested support for competing hypotheses in different subgroups of young adults defined by their history of cigarette smoking and individual difference variables (e.g., psychological reactance). One hypothesis predicted adaptive responding (GWs would lower smoking-related intentions) and another predicted defensive responding (GWs would raise smoking-related intentions). Methods Participants were an online sample of 1,169 Americans ages 18–24, who were randomly assigned either to view nine GWs designed by the FDA or to a no-label control. Both the intention to smoke in the future and the intention to quit smoking (among smokers) were assessed before and after message exposure. Results GWs lowered intention to smoke in the future among those with a moderate lifetime smoking history (between 1 and 100 cigarettes), and they increased intention to quit smoking among those with a heavy lifetime smoking history (more than 100 cigarettes). Both effects were limited to individuals who had smoked in some but not all of the prior 30 days (i.e., occasional smokers). No evidence of defensive “boomerang effects” on intention was observed in any subgroup. Conclusion Graphic warnings can reduce interest in smoking among occasional smokers, a finding that supports the adaptive-change hypothesis. GWs that target occasional smokers might be more effective at reducing cigarette smoking in young adults.
Force-dependent mechanical unfolding pathways of GFP

Abstract We characterize the force-dependent unfolding pathways and intermediate configurations of the green fluorescence protein (GFP) using novel atomistic simulations based on potential energy surface exploration. By using this approach, we are able to unfold GFP to significantly longer end-to-end distances, i.e. 40 nm, as compared to that seen in previous atomistic simulation studies. We find that there are four intermediate states between 5 and 40 nm end-to-end distance, where the intermediate configurations and unfolding pathways are strongly force-dependent. We additionally calculate the force-dependent lifetime of the 14 nm α β 1 intermediate, and demonstrate that it obeys Bell’s formula.
Assessing density functionals for the prediction of thermochemistry of Ti–O–Cl species

Titanium dioxide (TiO2) nanoparticles are widely used in contaminant remediation, photocatalysis and solar cell manufacturing. The low-cost production of TiO2 nanoparticles via the combustion of titanium tetrachloride (TiCl4) in oxygen is thus an important industrial process. To accurately model the °ame synthesis of TiO2 nanoparticles, reliable thermodynamic data of Ti–O–Cl species are indispensable but often unavailable. We therefore carried out benchmark calculations, using the left-eigenstate completely renormalized singles, doubles and perturbative triples(CR-CC(2,3),akaCR-CCL)methodwiththecc-pVTZbasisset,toobtaintheequilibrium structures and vibrational frequencies of selected Ti–O–Cl species; we then performed singlepoint CCSD(T)/aug-cc-pVL Z( L ¼ 3–5) calculations to extrapolate the CCSD(T)/CBS energies. After analyzing the experimental and calculated enthalpy of selected Ti–O–Cl species, the standard enthalpy of formation of the TiOCl2 molecule is determined to be � 600.5kJ/mol at 298K. The standard enthalpy of all other Ti–O–Cl species are determined accordingly. Finally, we assessed the accuracy of 42 popular density functionals for the Ti–O–Cl species. Among these assessed functionals, the B98 functional, tightly followed by B97-1 and B3LYP, exhibits the best overall performance in the prediction of the thermochemistry of the Ti–O–Cl species.