cssi/SciSciGPT-SciSciNet huggingface dataset:
Optimal Motor Location for the Reduction of Residual Vibrations in Mode-Coupled Ultra-Precision Manufacturing Machines

1 Contact Author ABSTRACT Ultra-precision manufacturing (UPM) machines are used to fabricate and measure complex parts having micrometer-level features and nanometer-level tolerances/surface finishes. Therefore, low-frequency residual vibrations that occur during the motion of the machines' axes must be minimized. Recent research by the authors has revealed that coupling the vibration modes of passively-isolated machines by properly selecting the location of the vibration isolators could lead to a drastic reduction in residual vibrations. However, the effect of motor location on the residual vibrations of mode-coupled UPM machines has not been rigorously analyzed. In this paper, an objective function which minimizes residual vibration energy with respect to motor location is defined and analyzed. It is shown to have a guaranteed global minimum irrespective of the parameters of the UPM machine. Conditions that ensure that the global minimum is located in a practically feasible design space are explored. Finally, the merits of optimal motor placement on residual vibration reduction are demonstrated using simulations conducted on a 5-axis ultra-precision machine tool.
GABAA receptors in the thalamus : α4 subunit expression and alcohol sensitivity

The inhibitory neurotransmitter gamma-aminobutyric acid (GABA) has long been implicated in the anxiolytic, amnesic, and sedative behavioral effects of alcohol. A large number of studies have investigated the interactions of alcohol with GABA receptors. Many investigators have reported effects of "high concentrations" (50-100 mM) of alcohol on GABA-mediated synaptic inhibition, but effects of the "low concentrations" (1-30 mM) of alcohol normally associated with mild intoxication have been elusive until recently. A novel form of "tonic inhibition" has been described in the central nervous system (CNS) that is generated by the persistent activation of extrasynaptic gamma-aminobutyric acid type A receptors (GABAA-Rs). These receptors are specific GABAA-R subtypes and distinct from the synaptic subtypes. Tonic inhibition regulates the excitability of individual neurons and the activity and rhythmicity of neural networks. Interestingly, several reports show that tonic inhibition is sensitive to low concentrations of alcohol. The thalamus is a structure that is critically important in the control of sleep and wakefulness. GABAergic inhibition in the thalamus plays a crucial role in the generation of sleep waves. Among the various GABAA-R subunits, the alpha1, alpha4, beta2, and delta subunits are heavily expressed in thalamic relay nuclei. Tonic inhibition has been demonstrated in thalamocortical relay neurons, where it is mediated by alpha4beta2delta GABAA-Rs. These extrasynaptic receptors are highly sensitive to gaboxadol, a novel hypnotic, but insensitive to benzodiazepines. Tonic inhibition is absent in thalamic relay neurons from alpha4 knockout mice, as are the sedative and analgesic effects of gaboxadol. The sedative effects of alcohol can promote sleep. However, alcohol also disrupts the normal sleep pattern and reduces sleep quality. As a result, sleep disturbance caused by alcohol can play a role in the progression of alcoholism. As an important regulator of sleep cycles, inhibition in the thalamus may therefore be involved in both the sedative effects of alcohol and the development of alcoholism. Investigating the effects of alcohol on both synaptic and extrasynaptic GABAA-Rs in the thalamus should help us to understand the mechanisms underlying the interaction between alcohol and sleep.
Animated icons: re-inventing visual cues for the visually impaired computer user

Universal access to information is critical for universal participation in society. The Graphical User Interface is a mainstream means for accessing the computing resources needed to access information. These interfaces have become challenging to the visually impaired.Many partially sighted individuals posses residual vision. While the enlargement of screen content is important, enlargement alone will not address all of issues involving the utilization of GUIs. While icons are generally useful, animation increases the usefulness of the icons. The sizes of static and animated icons are compared in order to ascertain the impact of animation on icon size.
Reducing HIV Transmission Risk by Increasing Serostatus Disclosure: A Mathematical Modeling Analysis

Persons living with HIV infection are encouraged to disclose their HIV-positive serostatus to prospective sex partners to decrease the likelihood of unsafe sex and HIV transmission. However, the effectiveness of serostatus disclosure as a preventive measure is not known. We developed a mathematical framework for assessing the HIV transmission risk reduction effectiveness of serostatus disclosure, examined how increasing the disclosure rate affects the transmission risk reduction effectiveness of disclosure, and explored the interaction between condom use and disclosure effectiveness. Under base-case assumptions, serostatus disclosure reduced the risk of HIV transmission by between 17.9% and 40.6% relative to no disclosure. Increasing the disclosure rate from the base-case value of 51.9–75.7% produced a 26.2–59.2% reduction in risk. The findings of this modeling study strongly support intervention efforts to increase both serostatus disclosure and condom use by persons living with HIV.
T-lymphocyte and B-lymphocyte dichotomy in anuran amphibians: I. T-lymphocyte proportions, distribution and ontogeny, as measured by E-rosetting, nylon wool adherence, postmetamorphic thymectomy, and non-specific esterase staining.

Abstract We used sheep erythrocyte (SRBC) E-rosetting, nylon wool fractionation thymectomy and nonspecific esterase staining to assess T-lymphocyte characteristics in Rana pipiens during various developmental stages. T-lymphocytes appear in the spleens of premetamorphic tadpoles. We found significant levels of lymphocytes classifiable as T-cells in the peripheral blood of adults, but fewer numbers of T-cells in the thymus, jugular bodies, spleen, pronephros, mesonephros, liver and bone marrow. In addition, thymectomized Xenopus laevis showed a sharp decrease in T-cells as evidenced by E-rosetting, ANAE stain and nylon wool fractionation. The presence of T-lymphocytes in anuran amphibians and the existence of a receptor for SRBC on a population of these cells, suggest conservation of T-cells during evolution.
An Environmental Chamber for FT-IR Measurements of Thin Films on Smooth Metals

A design of a cell to record IR spectra of monolayers on low area metals at elevated or reduced temperature and/or pressure is described. Its utility is illustrated with spectra of Langmuir-Blodgett monolayers of cadmium arachidate under nonambient conditions.
Complications and untoward effects of the tension-free vaginal tape procedure.

Abstract Objective To report our experience with our first 350 cases of tension-free vaginal tape (TVT), specifically assessing intraoperative complications, postoperative morbidity, and untoward effects of the procedure. Methods Although increased numbers of reports have documented the efficacy of the TVT procedure, there are minimal data about the incidence of complications and how they are managed. We performed a retrospective review of all patients undergoing the TVT procedure over a 4-year period to report intraoperative complications (bladder perforation and excessive bleeding), postoperative complications (de novo urge incontinence, voiding dysfunction, erosion, nerve injury, urinary retention, hematoma formation), and incidence of reoperation either for voiding dysfunction or for recurrent incontinence. Results A total of 350 patients were included in the study. Fifty-five percent (194) of women underwent the TVT procedure in conjunction with other vaginal surgery, and 45% (156) underwent the TVT alone. Seventy women (20%) had previous antiincontinence surgery. Intraoperative complications included 19 bladder perforations in 17 patients (4.9%) and three cases of significant bleeding (0.9%). Postoperatively, 17 women (4.9%) had voiding dysfunction and 42 (12%) required anticholinergic therapy beyond 6 weeks. Recurrent urinary tract infections developed in 38 (10.9%), erosion or poor healing in three (0.9%), hematoma in six (1.7%), and nerve injury in three (0.9%). Twenty-eight (8%) underwent urethral dilation in the postoperative period for varied amounts of voiding dysfunction. Of these, 82% were either improved or were cured. Six women (1.7%) underwent a takedown of the TVT procedure for continued voiding dysfunction, and two of these (33%) developed recurrent stress incontinence. To date, two patients (0.5%) have undergone another procedure for recurrent or persistent stress incontinence. Conclusion The TVT procedure is efficacious for the correction of stress incontinence. Our data show that it is a safe procedure with an acceptable complication rate when performed by surgeons who have experience with retropubic and transvaginal antiincontinence procedures.
Diverse aging rates in metazoans: targets for functional genomics

Aging, or senescence, has typically been measured by demographic analysis, which has its merits but is blind to key aspects of functional development and deterioration. If one uses demographic analyses, however, the approach providing most insight is the analysis of age-specific mortality. The continuing increase in DNA sequencing power combined with emerging computational techniques will allow in the near future detailed investigation of mechanisms of aging in diverse species beyond the typical laboratory bestiary. A comparative approach of this sort needs to consider, in addition to simple longevity, the effects of phylogeny and body size on the species in question. Insight may be gained from the study of species exhibiting accelerated aging relative to more "typical" species. These naturally short-lived species, such as several small shrews and marsupials, avoid the worry inherent in "accelerated aging" genotypes of common models, which is that they are only short-lived because of some idiosyncratic pathology unrelated to general aging. A case of special interest that has yet to be seriously investigated is the domestic dog, in which selective breeding has produced phenotypes within the same species that age at two-fold different rates. Exceptionally long-lived species offer exceptional opportunities to discover whether there are few or many ways to create long-lived organisms. Slow-aging species with the most to offer include bats and naked mole-rats. Perhaps no fundamental question in biology is more intriguing that why and how nature has produced such a dazzling array of aging rates. The development of functional genetics over the next several decades promises to lead us toward an answer.
Hemodynamic monitoring made easy

This volume was written primarily for nurses in the intensive care unit. It was written by one of the more knowledgeable and successful nurses in critical care academia today. Ms Fawcett has the necessary breadth of physiological insight and years of technical experience, and an easy writing style to describe complex ideas and applications related to bedside hemodynamic monitoring to an exceptional degree. The book is an ambitious undertaking to place critical care nurses at the center of protocolized resuscitation from the perspective of active participation. I recommend this volume to junior nurses starting out in critical care medicine as well as more senior nursing staff who wish to take an active role in understanding bedside monitoring-driven resuscitation protocols and their protocol development. The book is divided into three sections. Section one is the obligatory description of cardiovascular physiology and the ability to use monitoring devices accurately to collect the measures of pressure, flow, and oxygen saturation necessary to treat the critically ill. I like the fact that all chapters are salted with short quizzes so that the reader can test their retention of specific details before proceeding. This approach in a non-threatening fashion is a wonderful and non-confrontational teaching aid and brings the student to the table to sample the foundations of why monitoring is done. Section two is the meat of the book. It takes the understanding of physiology to the practical bedside application with fundamentals of hemodynamic monitoring and the effect of ventilation on measured hemodynamic variables. These chapters show insight and understanding as to what the novice needs to know and why. The final section takes hemodynamic monitoring into the realm of future monitoring techniques and protocolized care. These two final chapters are the dessert. They describe novel and evolving bedside monitoring as it may be in the future and then ends with the very relevant chapter on hemodynamic monitoring-directed therapy. Recent studies cited by Ms Fawcett underscore the leadership role of bedside nursing in the resuscitation of hemodynamically unstable patients. The references cited in the book are recent, relevant and reflect some of the best studies in the field. The figures, although slightly small because of the size of the book itself, are clear and appropriate. I especially like the fact that Ms Fawcett does not overpower the reader while providing a powerful and relevant amount of material for the practical and effective practice of bedside hemodynamic monitoring. It is a pleasure to read and is an important reference to keep once completed.
Computational analysis of biomechanical contributors to possible endovascular graft failure.

This paper evaluates numerically coupled blood flow and wall structure interactions in a representative stented abdominal aortic aneurysm (AAA) model, leading potentially to endovascular graft (EVG) failure. A total of 12 biomechanical contributors to possible EVG migration were considered. The results show that after EVG insertion for the given model, the peak AAA sac-pressure was reduced to 14.2 mmHg (11.8% of plumen), and hence the maximum von Mises wall stress and wall deformation dropped by factors of 20 and 10, respectively. Thus, an EVG can significantly reduce sac pressure, mechanical stress, pulsatile wall motion, and the maximum diameter in AAAs and hence prevent AAA rupture effectively. In the absence of endoleaks, elevated sac-pressure can still be caused by fluid-structure interactions between the EVG, stagnant blood, and AAA wall. EVG migration forces vary from 1.4 to 7 N for different EVG geometries, material properties, and hemodynamic conditions. AAA-neck angle, iliac bifurcation angle, neck aorta-to-iliac diameter ratio, EVG size, aorto-uni-iliac EVG, and hypertension play important roles in generating forces potentially leading to EVG migration.
Feature-based terrain classification for LittleDog

Recent work in terrain classification has relied largely on 3D sensing methods and color based classification. We present an approach that works with a single, compact camera and maintains high classification rates that are robust to changes in illumination. Terrain is classified using a bag of visual words (BOVW) created from speeded up robust features (SURF) with a support vector machine (SVM) classifier. We present several novel techniques to augment this approach. A gradient descent inspired algorithm is used to adjust the SURF Hessian threshold to reach a nominal feature density. A sliding window technique is also used to classify mixed terrain images with high resolution. We demonstrate that our approach is suitable for small legged robots by performing real-time terrain classification on LittleDog. The classifier is used to select between predetermined gaits to traverse terrain of varying difficulty. Results indicate that real-time classification in-the-loop is faster than using a single all-terrain gait.
Structure and mechanical properties of artificial protein hydrogels assembled through aggregation of leucine zipper peptide domains

Artificial protein hydrogels made from a triblock protein (designated AC10A, where A is an acidic zipper domain and C10 comprises 10 repeats of the nonapeptide sequence exhibit normalized plateau storage moduli (G′∞/nkT) less than 0.13 at all concentrations, pH values, and ionic strengths examined. These gels are surprisingly soft due to loop formation at the expense of bridges between physical junctions. Molecular-level evidence of loop formation is provided by strong fluorescence energy transfer (FRET) between distinct chromophores placed at the C- and N-termini of labelled chains diluted in an excess of unlabelled chains. The tendency to form loops originates from the compact size of the random coil midblock (mean RH(C10) ≈ 20 A, determined from quasi-elastic light scattering of C10), and is facilitated by the ability of the leucine zipper domains to form antiparallel aggregates. Although the aggregation number of the leucine zipper domains is small (tetrameric, determined from multi-angle static light scattering of AC10 diblock), the average center-to-center distance between aggregates is roughly 1.5 times the average end-to-end distance of the C10 domain in a 7% w/v network. To avoid stretching the C10 domain, the chains tend to form loops. Changes in pH or ionic strength that expand the polyelectrolyte midblock favor bridging, leading to greater G′∞ as long as leucine zipper endblocks do not dissociate. Understanding of the network structure provided successful design strategies to increase the rigidity of these hydrogels. In contrast to intuitive design concepts for rubber and gel materials, it was shown that increasing either the length or the charge density of the midblock increases rigidity, because fewer chains are wasted in loop formation.
Loss of striatal mu1 opiate binding by substantia nigra lesions in the rat.

Opiate receptors have been identified within the striatum and some have been localized presynaptically to nigrostriatal neurons. Using unilateral ablative lesion of the substantia nigra, the authors examined binding in the ipsilateral and contralateral striata. Lesions significantly lowered both /sup 3/H(D-Ala/sup 2/, MePhe/sup 4/, Gly(ol)/sup 5/) enkephalin (DAGO) and /sup 3/H(D-Ala/sup 2/,Leu/sup 5/) enkephalin (DADL) binding. The inclusion of competitors in these assays revealed a decrease in both mu/sub 1/ and mu/sub 2/ receptors. Mu/sub 1/ binding was slightly more sensitive to the lesioning than mu/sub 2/ binding. Selective mu/sub 1/ and mu/sub 2/ binding assays supported these observations. No change in delta binding was observed in the lesioned striata. These studies raise the possibility that both mu/sub 1/ and mu/sub 2/, but not delta, receptors are localized presynaptically on nigrostriatal neurons.
Molecular epidemiology of rabies in the United States

Abstract Changes in demographics, land use, recreation and hunting practices in the last 50 years dramatically increased the public health importance of reservoirs for rabies in wild species in the United States. This article focuses on attributes of host natural history to interpret the molecular phylogenies of the rabies variant transmitted within a particular animal population and the threat to human health presented by this reservoir.
A Case of Pseudocholinesterase Deficiency in the PACU

A 39-year-old patient with unrecognized atypical pseudocholinesterase was given succinylcholine during the rapid-sequence induction process and subsequently had a prolonged neuromuscular blockade. The patient was reassured, sedated, and ventilated in the postanesthesia care unit (PACU). The primary nursing interventions included airway clearance, communication, comfort, and patient education. Several important learning experiences occurred for the nurses in the PACU related to identifying possible causes, ordering the pseudocholinesterase and dibucaine inhibition test, interpreting the results, and developing and delivering patient education. This article will provide the perianesthesia nurse with the fundamental understanding of the physiology, laboratory diagnostic interpretation, and nursing interventions needed to deliver evidence-based, high-quality care to patients diagnosed with pseudocholinesterase deficiency.
An electron microscopic and autoradiographic study of mesogleal organization and collagen synthesis in the sea anemone Aiptasia diaphana.

Electron microscopy and autoradiography (H3-proline) were used to determine the cell(s) responsible for collagen synthesis and lamination in the mesoglea of the sea anemone, Aiptasia diaphana. Mesogleal collagen is synthesized by the epidermal epitheliomuscular cells which contain much rough endoplasmic reticulum, and secretory vesicles attached to microtubules which cross the basal plasmalemma and anchor in the basement membrane; these cells incorporate large amounts of H3-proline. The mesogleal collagen fibers are non-striated, have clear centers, and a diameter of 200–260 A; their walls are composed of 65 A diameter subunit fibrils which appear to be helically oriented. Epitheliomuscular cells rest upon a subepidermal basement membrane which is composed of mesogleal collagen fibers, 65 A subunit fibrils, and dense granules. This subepidermal basement membrane labels definitively with H3-proline, and is the region where soluble collagen precursors apparently form subunit fibrils which associate to yield mesogleal fibers. The columnar mesogleal collagen fibers are arranged to form layers: the fibers of each layer have the same longitudinal orientation, while those of adjacent layers display an approximate orthogonal arrangement. It is felt that the subepidermal basement membrane is responsible for this organization of mesogleal fibers. Mesogleal amoebocytes do not label with H3-proline and show no ultrastructural evidence of collagen secretion.
Controlling Adhesion of Orthodontic Adhesives Through Adjustment of the Interphase Mechanical Properties

Abstract Adhesives for ceramic orthodontic brackets are so strong that instances of enamel fracture and bracket fracture have occurred during removal. Our approach to minimize the potential enamel damage was to modify the mechanical properties of the adhesive, a BIS GMA-silica composite, by use of diethyl phthalate which is a common plasticizer. The plasticizer, used in amounts up to 20% of the adhesive weight, significantly decreases the adhesive modulus and tensile strength. One objective of this research is to evaluate plasticizer stability in the adhesive via functional testing in a simulated oral environment. A second objective was to simulate, by use of finite element analysis, clinical loading conditions during orthodontic treatment and removal. The finite element analysis determined the changes in computed stresses due to plasticization. After 25 days in an artificial saliva solution held at 60°C, the bracket removal torque was lower for the 10% plasticized adhesive group than that for the non-pla...
Consumer protection laws: violator detection and enforcement strategy

A methodology is proposed for both the assessment and enforcement of consumer protection laws and regulations. An assessment model is presented to determine the effect of a law e.g., violation rate, characteristics and/or profile of violators and then a cost efficient law enforcement strategy is described that is aimed at the violator population identified by the assessment model. This methodology consists of a short enforcement campaign, directed mainly against the violators, and is then followed by an inexpensive maintenance program. Data for the assessment model are collected based upon an interrupted stratified time series design where the stratification scheme is selected by satisfying a minimum variance criterion. The stratification rule may vary so that a dynamic representation of the changing characteristics of the violator population is obtained.
Limited distortion in LSB steganography

It is well known that all information hiding methods that modify the least significant bits introduce distortions into the cover objects. Those distortions have been utilized by steganalysis algorithms to detect that the objects had been modified. It has been proposed that only coefficients whose modification does not introduce large distortions should be used for embedding. In this paper we propose an effcient algorithm for information hiding in the LSBs of JPEG coefficients. Our algorithm uses parity coding to choose the coefficients whose modifications introduce minimal additional distortion. We derive the expected value of the additional distortion as a function of the message length and the probability distribution of the JPEG quantization errors of cover images. Our experiments show close agreement between the theoretical prediction and the actual additional distortion.
Surface and interfacial fourier transform infrared spectroscopic studies of latexes. XVI. Quantitative analysis of surfactant in multilayered films

Migration and concentration levels of sodium dioctylsulfosuccinate (SDOSS) surfactant molecules in 50%/50% styrene/butyl acrylate latex were detected at the film-substrate (F-S) and film-air (F-A) interfaces in mono- and double-layered films. For the purpose of quantitative analysis, absorption coefficients of the 1,056 and 1,046 cm -1 bands attributed to the SO 3 - Na + ... HOOC and SO 3 - Na + ... H 2 O associations, respectively, were determined. Using group theory formalism, local geometries of the SO 3 - Na + hydrophilic groups of SDOSS can be predicted. The analysis is extended to the 1,261 and 1,209 cm -1 bands resulting from the S - O asymmetric stretching vibrations, due to the same SO 3 - Na + ... HOOC and SO 3 - Na + ... H 2 O associations, and to the 1,290 and 1,236 cm -1 bands, due to asymmetric stretching modes of hydrophobic tails of the SDOSS. By the use of polarization attenuated total reflectance Fourier transform infrared (ATR FT-IR) experiments, these studies show that hydrophilic SO 3 - Na + ends on SDOSS are preferentially parallel to the film surface. At the same time, hydrophobic tails are perpendicular to the surface. The assessment of the amounts of SDOSS at the F-S and F-A interfaces was obtained by quantitative ATR FTIR analysis, which was extended to the silicone-modified double-layer latex films. In this case, the concentration of SDOSS molecules decreases as the depth of penetration increases. The highest concentrations of SDOSS molecules are detected at the shallowest depths near the surface of the top layer and the interfacial regions between the latex layers.
Analysis and estimation of soil moisture at the catchment scale using EOFs

Soil moisture patterns and dynamics are important for numerous applications such as flood forecasting, climate modeling, and management of agricultural lands. Unfortunately, widespread observations of soil moisture are not currently available at the spatial scale of most of these applications. Given these data limitations and the complexity of soil moisture dynamics, there is a need to gain a better understanding of soil moisture patterns and to develop methods that can efficiently estimate these patterns from limited observations. In this paper, we use Empirical Orthogonal Function (EOF) analysis to study the Tarrawarra soil moisture dataset from Australia. EOF analysis partitions the observed variation into a series of time-invariant spatial patterns (EOFs) that can be multiplied by temporal varying (but spatially constant) coefficients and summed to reconstruct observed soil moisture patterns. Using this approach, we identify two spatial patterns underlying soil moisture variability at Tarrawarra, which supports previous contentions that the spatial patterns are controlled by local soil properties in wet and dry conditions and topographic characteristics during intermediate conditions. We also use the EOF analysis to identify points whose variability is most representative of each of the underlying spatial patterns and thus can be used to monitor these distinct modes of variability. Finally, we show that the EOF approach can be used to estimate soil moisture patterns for unobserved times if a field campaign has collected detailed soil moisture observations for a limited time period in the past.
Retrograde transport of [3H]proline: a widespread phenomenon in the central nervous system

[3H]Proline was injected into spinal cord, pons, inferior colliculus, superior colliculus, lateral geniculate nucleus, pulvinar-LP complex and visual cortex of cats or rats. After 1–3 days' survival the animals were perfused with formalin or mixed aldehydes. Autoradiography showed labeling of cell bodies in most regions known to project to the injection sites. The ability to take up and retrogradely transport [3H]proline appears to be a common property of central neurons. We infer that the transport of this compound is unrelated to its possible status as a neurotransmitter.
Redox signaling regulates commensal-mediated mucosal homeostasis and restitution and requires formyl peptide receptor 1

The mammalian gut microbiota is essential for normal intestinal development, renewal, and repair. Injury to the intestinal mucosa can occur with infection, surgical trauma, and in idiopathic inflammatory bowel disease. Repair of mucosal injury, termed restitution, as well as restoration of intestinal homeostasis involves induced and coordinated proliferation and migration of intestinal epithelial cells. N-formyl peptide receptors (FPRs) are widely expressed pattern recognition receptors that can specifically bind and induce responses to host-derived and bacterial peptides and small molecules. Here we report that specific members of the gut microbiota stimulate FPR1 on intestinal epithelial cells to generate reactive oxygen species via enterocyte NADPH oxidase 1 (NOX1), causing rapid phosphorylation of focal adhesion kinase (FAK) and extracellular signal-regulated kinase mitogen-activated protein kinase. These events stimulate migration and proliferation of enterocytes adjacent to colonic wounds. Taken together, these findings identify a novel role of FPR1 as pattern recognition receptors for perceiving the enteric microbiota that promotes repair of mucosal wounds via generation of reactive oxygen species from the enterocyte NOX1.
Phonons and Free Carriers in a Strained Hexagonal GaN-AlN Superlattice Measured by Infrared Ellipsometry and Raman Spectroscopy

The low-frequency noise in GaN-based Metal-Oxide-Semiconductor Heterostructure Field Effect Transistors (MOS-HFETs) and HFETs on sapphire and n-SiC substrates were studied. Hooge parameter at zero gate bias was calculated about 8 × 10−4 for both types of the devices. The AlGaN/GaN MOS-HFETs exhibited extremely low gate leakage current and much lower noise at both positive and negative gate biases. These features demonstrate the high quality of the SiO2/AlGaN heterointerface and feasibility of this technology for high-power microwave transmitter and high-power, high-temperature switches. Phonon and free-carrier effects in a strained hexagonal (α) {GaN}l -{AlN} m superlattice (SL) heterostructure (l = 8 nm, m = 3 nm) are studied by infrared spectroscopic ellipsometry (IRSE) and micro (µ)-Raman scattering. Growth of the heterostructures was performed by metal-organic vapor phase epitaxy (MOVPE) on (0001) sapphire. An unstrained 1 µm-thick α-GaN layer was deposited prior to the SL. SL phonon modes are identified combining results from both IRSE and µ-Raman techniques. The shift of the GaN-sublayer phonon modes is used to estimate an average compressive SL stress of σ xx ∼ - 4.3 GPa. The IRSE data reveal a free-carrier concentration of ne ∼ 5×1018 cm−3 within the undoped SL GaN-sublayers. According to the vertical carrier confinement, the free-carrier mobility is anisotropic, and the lateral mobility (µ⊥ ∼ 400 cm2/Vs, polarization E⊥c-axis) exceeds the vertical mobility (µ||| ∼ 24 cm2/Vs, E||c) by one order of magnitude.
THE PSYCHOPATHOLOGY OF DEVELOPMENT: INVESTIGATING THE ETIOLOGY OF SCHIZOPHRENIA

Emerging trends of research on schizophrenia support the view that the systematic investigation of developmental processes of human behavior holds the greatest promise for understanding the etiology of the disorder. A developmental model, to be useful in suggesting new empirical research, must delineate the type of mechanism through which family interactions exert their effect on the developing resources of the child.
Xenotransplantation and xenogeneic infections

The ongoing shortage of human organs and tissues for transplantation, coupled with scientific and biotechnological advances, has catalyzed new attempts to use animal tissues in humans — a field kno...
Acquired immune and inflammatory myopathies: pathologic classification.

Purpose of reviewWe discuss pathology-based characterization and classification of acquired immune and inflammatory myopathies (IIMs).Recent findingsSeveral types of IIMs do not fit well into the typical IIM subclassifications: dermatomyositis, polymyositis and inclusion body myositis (IBM). Myopath
Heterotrophic and autotrophic assimilation of fatty acids by two scleractinian corals, Montastraea faveolata and Porites astreoides

We determined the source of fatty acids in scleractinian corals by separately measuring and comparing the δ13C values of fatty acids in zooxanthellae and coral hosts from two scleractinian coral species (Montastraea faveolata and Porites astreoides) from reefs of the Florida Reef Tract. Using an isotopic mass balance approach, we show that zooxanthellae are the dominant source of fatty acids and that in many colonies heterotrophic feeding can be an important and significant source of essential ω3 fatty acids for corals. There is considerable variability in feeding behavior within species, between species, and within single reef sites. In individual colonies, essential ω3 fatty acids and energy resources such as triglycerides can be acquired from separate dietary sources, showing the importance of resource partitioning within the coral animal. Consistently, individual coral colonies acquire most of their energy-rich saturated fatty acids from their symbiotic zooxanthellae. The particular feeding mode by which corals acquire their fatty acids appears to be specific to each coral colony. The ability of corals to modulate their feeding modes under different environments may provide an adaptive mechanism to sustain growth under stressful conditions.
Uncertainties in CO2 Capture and Sequestration Costs

Publisher Summary The cost of CO2 avoidance depends on a wide variety of factors and assumptions whose impacts have not been fully considered in past assessments of carbon capture and sequestration technologies. Development of improved technology to capture and sequester the CO2 emitted by power plants using fossil fuels—especially coal—is the subject of major research efforts worldwide. The attraction of this option is that it would allow abundant world resources of fossil fuels to be used for power generation and other applications without contributing significantly to atmospheric emissions of greenhouse gases. The two key barriers to carbon capture and sequestration (CCS), however, are the high cost of current CO2 capture technologies, and uncertainties regarding the technical, economic and political feasibility of CO2 storage options. As part of the U.S. Department of Energy's (USDOE's) Carbon Sequestration Program, an integrated modeling framework has been developed to evaluate the performance and costs of alternative CO2 capture and sequestration technologies for fossil-fueled power plants, in the context of multi-pollutant control requirements. This model (called the IECM-CS) allows for explicit characterization of the uncertainty or variability in any or all model input parameters. This chapter reviews the major sources of uncertainty or variability in CO2 cost estimates, and then uses the IECM-CS to analyze uncertainties in CO2 mitigation costs for currently available (amine-based) COR capture technologies applicable to coal-fired power plants.
Monitoring the remineralization of early simulated lesions using a pH cycling model with CP-OCT

If caries lesions are detected early enough they can be arrested by chemical intervention and dietary changes without the need for chemical intervention. Optical coherence tomography is ideally suited to monitor the changes that occur in caries lesions as a result of nonsurgical intervention, since OCT can nondestructively image the internal structure of the lesion. One of the most important changes that occurs in a lesion is preferential deposition of mineral in the outer surface zone. The deposition creates a highly mineralized and weakly scattering surface zone that is clearly visible in OCT images. Since this zone is near the highly reflective surface it is necessary to use cross-polarization OCT imaging to resolve this zone. Several CP-OCT studies have been conducted employing different remineralization models that produce lesions with varying mineral gradients. Previous studies have also demonstrated that automated algorithms can be used to assess the lesion depth and severity even with the presence of the weakly reflective surface zone. In this study we investigated the remineralization of lesions of varying severity using a pH cycling remineralization model and the change of the lesion was monitored using CP-OCT. Although the lesion depth and severity decreased after remineralization, there was still incomplete remineralization of the body of the lesion.
Comment on “Fractional crystallization of iron meteorites: Constant versus changing partition coefficients” by J. H. Jones

— Jones (1994) demonstrated that fractional crystallization of IIIAB iron meteorites may result in a log Au vs. log Ni plot of constant slope even though kAu and kNi change. Jones' example is a special case, however, and does not necessarily describe behavior by other elements or in other metallic magmas.
Sudden cardiac arrest in intercollegiate athletes: detailed analysis and outcomes of resuscitation in nine cases

Background Public access defibrillation programs have demonstrated a survival benefit in persons with out-of-hospital cardiac arrest. However, little is known about the effectiveness of early defibrillation in young competitive athletes with sudden cardiac arrest (SCA). Objectives The purpose of this study was to investigate the details and outcomes of resuscitation in a cohort of intercollegiate athletes with SCA. Methods Nine cases of SCA in intercollegiate athletes occurring between 1999 and 2005 were identified through prior research and public media. A detailed questionnaire was completed by the certified athletic trainer involved in the resuscitation, and direct phone follow-up was achieved in every case. Results Nine intercollegiate athletes with SCA (4 basketball, 2 football, 2 lacrosse, and 1 swimming) had an average age of 21 years (range 18–30 years). All 9 athletes had a witnessed collapse, 7 occurred during practice, 1 during competition, and 1 during organized weight training. Cardiopulmonary resuscitation (CPR) was initiated within 30 seconds after cardiac arrest in 6 cases and by 1 minute in 2 additional cases. An automated external defibrillator (AED) was provided by an athletic trainer in 5 cases and by arriving emergency medical services (EMS) in 4 cases. The initial cardiac rhythm was confirmed or suspected ventricular fibrillation in 7 athletes, pulseless idioventricular rhythm in 1 case, and unknown in 1 case. In 7 cases a shock was deployed, with an average time from cardiac arrest to defibrillation of 3.1 minutes (range 1–7.5 minutes). The average time from arrest to defibrillation decreased significantly if an AED was provided by an athletic trainer as compared with the responding EMS (1.6 vs 5.2 minutes; P = .046). Eight of the 9 athletes died. The underlying cause of sudden cardiac death was hypertrophic cardiomyopathy in 5, commotio cordis in 2, and myocardial infarction in 1. Diagnostic studies in the survivor demonstrated no structural heart disease or precise cause of SCA. Conclusion Despite witnessed collapse, immediate CPR, and prompt AED use in most cases, early defibrillation showed limited success, and survival was less than expected in this small cohort of intercollegiate athletes. More research is needed to determine the effectiveness of early defibrillation and factors that affect survival in young athletes with SCA.
Key Role of Non Equilibrium Spin Density in Determining Spin Torque

In summary, starting from the NEGF formalism, we have showed that the current induced torque is proportional to the spin density at the ferromagnetic surface. This automatically gives the well known Slonczewski and field terms in the current torque thus showing the relation between their relative amplitudes without the phenomenology commonly used in literature. We obtain a reasonable quantitative agreement with experimental data that validates our model. From the same simulation, we show that when the spin injection efficiency is 100%, the torque transfer efficiency saturates at 50%. This result is significant considering that the existing devices are not far from this limit and hence novel device designs [S. Salahuddin and S. Datta, 2006] going beyond the conventional three layer structure may be necessary to reduce the switching current to technologically viable levels (~105 A/cm2).
Chloride efflux inhibits single calcium channel open probability in vertebrate photoreceptors: chloride imaging and cell-attached patch-clamp recordings.

The present study uses cell-attached patch-recording techniques to study the single-channel properties of Ca 2+ channels in isolated salamander photoreceptors and investigate their sensitivity to reductions in intracellular Cl - . The results show that photoreceptor Ca 2+ channels possess properties similar to L-type Ca 2+ channels in other preparations, including (1) enhancement of openings by the dihydropyridine agonist, (-)BayK8644; (2) suppression by a dihydropyridine antagonist, nisoldipine; (3) single-channel conductance of 22 pS with 82 mM Ba 2+ as the charge carrier; (4) mean open probability of 0.1; (5) open-time distribution fit with a single exponential (τ 0 = 1.1 ms) consistent with a single open state; and (6) closed time distribution fit with two exponentials (τ c1 = 0.7 ms, τ c2 = 25.4 ms) consistent with at least two closed states. Using a Cl - -sensitive dye to measure intracellular [Cl-], it was found that perfusion with gluconate-containing, low Cl - medium depleted intracellular [Cl - ]. It was therefore possible to reduce intracellular [Cl-] by perfusion with a low Cl - solution while maintaining the extracellular channel surface in high Cl - pipette solution. Under these conditions, the single-channel conductance was unchanged, but the mean open probability fell to 0.03. This reduction can account for the 66% reduction in whole-cell Ca 2+ currents produced by perfusion with low Cl- solutions. Examination of the open and closed time distributions suggests that the reduction in open probability arises from increases in closed-state dwell times. Changes in intracellular [Cl-] may thus modulate photoreceptor Ca 2+ channels.
Inhibition of Salmonella by Sodium Nitrite and Potassium Sorbate in Frankfurters

All beef frankfurters and beef-pork frankfurters containing various levels of sodium nitrite (0, 50, or 156 ppm) or potassium sorbate (0, 0.26, or 0.39%) alone or in combination (50 ppm nitrite + 0.26% sorbate) were prepared. Frankfurters were inoculated with nalidixic acid resistant Salmonella and incubated at 15°C and 27°C for up to 21 days. Frankfurters formulated with 50 or 156 ppm nitrite and incubated at 27°C, or 50 ppm nitrite and incubated at 15°C failed to inhibit the growth of Salmonella. Sorbate alone and sorbate in combination with 50 ppm nitrite were equally effective in inhibiting Salmonella at either temperature and were equivalent to 156 ppm nitrite in inhibiting Salmonella at 15°C.
The recognition and treatment of lyme disease

Abstract Lyme disease is the most-common tick-borne disease in the United States, and its incidence is increasing, especially after the damp winter of 1993–1994 in the Northeast. In 1982, investigators discovered that Lyme disease was caused by the spirochete, Borrelia burgdorferi. Since then, several strains of that organism have been described, possibly explaining differing clinical presentations in Europe and the United States. It is crucial to diagnose Lyme disease in its earliest phases, as treatment with antibiotics usually results in a complete cure. Failure to make an early diagnosis and certain genetic factors contribute to a pattern of chronic disease in some patients. Diagnosis is made difficult by lack of a history or finding of a tick bite and by the fact that the pathognomonic finding, the rash of erythema chronicum migrans, is seen in only a minority of cases. Serologic diagnosis depends on the enzyme-linked immunosorbent assay, which is neither specific nor reliable, and the Western blot, which is not yet standardized. Particularly vexing is the confusion of Lyme disease with fibromyalgia, a common rheumatic disease of uncertain etiology with many overlapping symptoms. This confusion often leads to prolonged, unnecessary, and expensive treatments with dubious results. In general, Lyme disease responds well to a variety of oral and parenteral antibiotics. Special problems arise in the treatment of Lyme disease in pregnancy and in the choice of antibiotics in growing children. A vaccine for Lyme prophylaxis is expected for high-risk individuals.
Role of nitric oxide in the vasodilator response to mental stress in normal subjects

Vascular production of nitric oxide (NO) plays an important role in a variety of physiologic processes. This study examines the contribution of NO to the vasodilator response to mental stress. The effects of mental arithmetic testing on forearm vascular dynamics were analyzed in 15 normal subjects (9 men; age 45 +/- 12 years) during intraarterial infusion of either saline or N(G)-monomethyl-L-arginine (L-NMMA; 4 micromol/min for 15 minutes), an inhibitor of NO synthesis. The effect of L-NMMA on endothelium-independent vasodilation induced by intraarterial infusion of sodium nitroprusside was also studied in 11 of the 15 subjects. Forearm blood flow was measured by plethysmography. Mental stress increased forearm blood flow from 2.35 +/- 0.84 to 5.06 +/- 2.66 ml/min/dl (115%) during saline and from 1.72 +/- 0.59 to 2.81 +/- 0.99 ml/min/dl (63%) during L-NMMA infusion. The vasodilator effect of mental stress was significantly lower during L-NMMA infusion than during saline (1.1 +/- 0.65 vs 2.71 +/- 2.15 ml/min/dl; p = 0.01). L-NMMA administration did not significantly change mean arterial pressure and heart rate responses to mental stress. In contrast, the vasodilator effect of sodium nitroprusside (1.6 microg/min) was similar during infusion of L-NMMA and during saline (3.75 +/- 1.55 vs 2.85 +/- 1.38 ml/min/dl; p = 0.16). These findings indicate that local release of NO is involved in the forearm vasodilator response to mental stress.