cssi/SciSciGPT-SciSciNet huggingface dataset:
Frequency and outcomes of primary central sleep apnea in a population-based study.

Abstract Background Primary central sleep apnea (PCSA) is believed to be rare and data regarding its prevalence and long-term outcomes are sparse. We used the Rochester Epidemiology Project (REP) resources to identify all Olmsted County, Minnesota, residents with an incident diagnosis of PCSA and their clinical outcomes. Methods We searched the REP database for all residents with polysomnography (PSG)-confirmed diagnoses of central sleep apnea (CSA) between 2007 and 2015. From these, we reviewed the PSGs and medical records to find those who had PCSA based upon accepted diagnostic criteria. Data based on detailed review of the medical records, including all clinical notes and tests were recorded for analysis. Results Of 650 patients identified with CSA, 25 (3.8%; 23 male) had PCSA, which was severe in most patients (n = 16, 64%). Of those, 23 (92%) patients were prescribed and 18/23 (78.2%) adherent to positive airway pressure therapy. Median duration of follow-up was 4.4 years (IQR:4.2). Four (16%) patients were subsequently diagnosed with cardiac arrhythmias, one (4%) with unstable angina, two (8%) with heart failure, five (20%) with mild cognitive impairment (MCI)/dementia and two (8%) with depression. Six (25%) patients died (median time to death = 5 years; IQR:4.8), three of whom had Lewy body dementia. Conclusions In this population-based study, PCSA was rare and when present, was severe in a majority of patients. The mortality rate was high. Most frequently observed disorders during follow-up were mild cognitive impairment (MCI)/dementia followed by cardiac arrhythmias; it is possible that these entities were present and not recognized prior to the diagnosis of PCSA.
Tweeting Outside the Lines: Normalization and Fragmentation as Political Reporters Break from the Mainstream

The field of journalism is experiencing intense diversification in form and message while trying to overcome widespread public disaffection by reinforcing professional norms. This study focuses on ...
The Enhanced Finite State Projection algorithm, using conditional moment closure and time-scale separation

The Chemical Master Equation (CME) is commonly used to describe the stochastic behavior of biomolecular systems. However, in general, the CME’s dimension is very large or infinite, so analytical or even numerical solutions may be difficult to achieve. The truncation methods such as the Finite State Projection (FSP) algorithm alleviate this issue to some extent but not completely. To further resolve the computational issue, we propose the Enhanced Finite State Projection (EFSP) algorithm, in which the ubiquitous time-scale separation is utilized to reduce the dimension of the CME. Our approach combines the original FSP algorithm and the model reduction technique that we developed, to approximate an infinite dimensional CME with a finite dimensional CME that contains the slow species only. Unlike other time-scale separation methods, which rely on the fast-species counts’ stationary conditional probability distributions, our model reduction technique relies on only the first few conditional moments of the fast-species counts. In addition, each iteration of the EFSP algorithm relies on the solution of the approximated CME that contains the slow species only, unlike the original FSP algorithm relies on the solution of the full CME. These two properties provide a significant computation advantage. The benefit of our algorithm is illustrated through a protein binding reaction example.
Measuring cost inefficiency: A dual approach

Abstract Total cost inefficiency comprises technical inefficiency and allocative inefficiency. Measuring cost inefficiency with these two components has been challenging both theoretically and empirically. Current literature has provided some solutions. However, these solutions are restricted to specific functions and their empirical estimations are complicated to implement, which lead to limited applications. Using the duality between production and cost functions, this paper proposes a new approach that is simple for estimation and applicable to general cases. Firstly, we define two types of allocative inefficiency and derive their input cost share inequalities. Secondly, a three-stage procedure is developed to estimate total cost inefficiency and its two components. Finally, an empirical presentation based on the existing data supplements the theory. Our results show that this solution can identify the inefficiency for each input and derive robust estimates of economies of scale, which are important for both policy implications and managerial decisions.
Quality and Cost of Care by Hospital Teaching Status: What Are the Differences?

Policy Points In two respects, quality of care tends to be higher at major teaching hospitals: process of care and long-term survival of cancer patients following initial diagnosis. There is also evidence that short-term (30-day) mortality is lower on average at such hospitals, although the quality of evidence is somewhat lower. Quality of care is mulitdimensional. Empirical evidence by teaching status on dimensions other than survival is mixed. Higher Medicare payments for care provided by major teaching hospitals are partially offset by lower payments to nonhospital providers. Nevertheless, the payment differences between major teaching and nonteaching hospitals for hospital stays, especially for complex cases, potentially increase prices other insurers pay for hospital care. CONTEXT The relative performance of teaching hospitals has been discussed for decades. For private and public insurers with provider networks, an issue is whether having a major teaching hospital in the network is a "must." For traditional fee-for-service Medicare, there is an issue of adequacy of payment of hospitals with various attributes, including graduate medical education (GME) provision. Much empirical evidence on relative quality and cost has been published. This paper aims to (1) evaluate empirical evidence on relative quality and cost of teaching hospitals and (2) assess what the findings indicate for public and private insurer policy. METHODS Complementary approaches were used to select studies for review. (1) Relevant studies highly cited in Web of Science were selected. (2) This search led to studies cited by these studies as well as studies that cited these studies. (3) Several literature reviews were helpful in locating pertinent studies. Some policy-oriented papers were found in Google under topics to which the policy applied. (4) Several papers were added based on suggestions of reviewers. FINDINGS Quality of care as measured in process of care studies and in longitudinal studies of long-term survival of cancer patients tends to be higher at major teaching hospitals. Evidence on survival at 30 days post admission for common conditions and procedures also tends to favor such hospitals. Findings on other dimensions of relative quality are mixed. Hospitals with a substantial commitment to graduate medical education, major teaching hospitals, are about 10% to 20% more costly than nonteaching hospitals. Private insurers pay a differential to major teaching hospitals at this range's lower end. Inclusive of subsidies, Medicare pays major teaching hospitals substantially more than 20% extra, especially for complex surgical procedures. CONCLUSIONS Based on the evidence on quality, there is reason for patients to be willing to pay more for inclusion of major teaching hospitals in private insurer networks at least for some services. Medicare payment for GME has long been a controversial policy issue. The actual indirect cost of GME is likely to be far less than the amount Medicare is currently paying hospitals.
Evaluating the Question: The Instructor’s Side of Adaptive Learning

Many people in the education sector are aware of the benefits students derive from adaptive learning systems. Unfortunately, what is not well known is that an adaptive learning system can also augment the instructor’s understanding of what learning has occurred. Valid and relevant questions used by the adaptive learning system can provide an instructor with real-time insight into the level of knowledge attained by each individual student. Similarly, the same sort of knowledge can also indicate learning deficits that might affect an entire class and allow for an instructor to accurately respond to the student’s learning needs in an informed way.
Features importance in seizure classification using scalp EEG reduced to single timeseries

Seizure detection and seizure-type classification are best performed using intra-cranial or full-scalp electroencephalogram (EEG). In embedded wearable systems however, recordings from only a few electrodes are available, reducing the spatial resolution of the signals to a handful of timeseries at most. Taking this constraint into account, we tested the performance of multiple classifiers using a subset of the EEG recordings by selecting a single trace from the montage or performing a dimensionality reduction over each hemispherical space. Our results support that Random Forest (RF) classifiers lead most ef-ficient and stable classification performances over Support Vector Machines (SVM). Interestingly, tracking the feature importances using permutation tests reveals that classical EEG spectrum power bands display different rankings across the classifiers: low frequencies (delta, theta) are most important for SVMs while higher frequencies (alpha, gamma) are more relevant for RF and Decision Trees. We reach up to 94.3% {mp} 5.3% accuracy in classifying absence from tonic-clonic seizures using state-of-art sampling methods for unbalanced datasets and leave-patients-out fold cross-validation policy.
NANOPARTICLES FOR BIOSENSORS

Publisher Summary This chapter outlines a few major classes of optical biosensors. Their applications for detection and diagnostic screening for biomolecules are discussed. Furthermore, it highlights some of the key fundamental properties of certain nanostructures that make them ideal for these types of specific biosensing applications. Nanoscience has led to a revolution in both traditional and still-developing areas of biotechnology, material sciences, chemistry, medicine, electronics, computation, and information technology. The development of new and better nanomaterials is at the leading edge of the rapidly developing field. The unique size-dependent physical and chemical properties of nanomaterials make them superior and indispensable in many areas of science and technology research and development. Nanomaterials have been developed at a tremendous speed over the past decade. Starting from original sphere-shaped nanoparticles, more materials broadly defined as nanomaterials such as nanotubes, nanowires, and quantum dots (QDs) have been prepared. These nanoparticles have diverse shapes and structures. Several applications have used the unique properties of these nanoparticles, such as next-generation computer chips, high-sensitivity sensors, and long-lasting medical implants. Among these applications, nanomaterials-based biosensors are one of the most significant. Different types of nanoparticles not only require specific methods of synthesis, characterization, and modification, but each type also needs optimized experimental conditions. Finally, this chapter lists the synthesis methods of three types of nanoparticles: dye-doped silica nanoparticles, QDs, and magnetic nanoparticles.
Structure of beta-lactam synthetase reveals how to synthesize antibiotics instead of asparagine.

The enzyme β-lactam synthetase (β-LS) catalyzes the formation of the β-lactam ring in clavulanic acid, a clinically important β-lactamase inhibitor. Whereas the penicillin β-lactam ring is generated by isopenicillin N synthase (IPNS) in the presence of ferrous ion and dioxygen, β-LS uses ATP and Mg2+ as cofactors. According to sequence alignments, β-LS is homologous to class B asparagine synthetases (AS-Bs), ATP/Mg2+-dependent enzymes that convert aspartic acid to asparagine. Here we report the first crystal structure of a β-LS. The 1.95 A resolution structure of Streptomyces clavuligerus β-LS provides a fully resolved view of the active site in which substrate, closely related ATP analog α,β-methyleneadenosine 5′-triphosphate (AMP-CPP) and a single Mg2+ ion are present. A high degree of substrate preorganization is observed. Comparison to Escherichia coli AS-B reveals the evolutionary changes that have taken place in β-LS that impede interdomain reaction, which is essential in AS-B, and that accommodate β-lactam formation. The structural data provide the opportunity to alter the synthetic potential of β-LS, perhaps leading to the creation of new β-lactamase inhibitors and β-lactam antibiotics.
Characterization of Automotive Catalysts Exposed to the Fuel Additive MMT

A series of in-use catalysts having mileage of 22,000 to 43,000 miles was characterized to determine the effect of the fuel additive MMT. The analytical techniques included visual examination, x-ray fluorescence, x-ray diffraction, optical microscopy, scanning electron microscopy, and electron microprobe. In addition, catalyst activity was measured and compared to the catalyst activity from a pulsator aged catalyst without the MMT additive in the feed gas composition. Characterization results show a significantly thick layer (5-20 microns) covering the surface of the catalysts which results in the increase of mass transfer resistance. Steady state R and light-off measurements indicated catalyst efficiency is also significantly reduced as exposure to MMT is increased.
Familial hypertrophic cardiomyopathy: a genetic model of cardiac hypertrophy

Familial hypertrophic cardiomyopathy is an autosomal dominant disorder manifesting as cardiac hypertrophy in the absence of increased cardiac work load, which has been studied as a model of myocardial hypertrophy in humans. Hypertrophic cardiomyopathy is genetically heterogeneous with three known disease-genes and two further mapped loci. The disease-genes encode contractile proteins of the thick and thin filaments of the sarcomere: the beta cardiac myosin heavy chain gene on chromosome 14q11, the alpha tropomyosin gene on chromosome 15q2 and the cardiac troponin T gene on chromosome 1q3. Other disease loci have been mapped to chromosome 11p13-q13 and 7q3. In each known disease-gene a number of different mutations have been identified; these are missense mutations, or mutations leading to modest alterations of peptide structure, but not null alleles. Specific mutations are associated with different disease severity and may provide diagnostic and prognostic information not available from clinical assessment. Genetic and functional data suggest that mutations which cause hypertrophic cardiomyopathy act as dominant negative alleles that impair cross-bridge cycling and contractile function and interfere with sarcomere assembly.
The effects of video self-evaluation on skill acquisition with Yoga postures

This study evaluated the use of video self-evaluation and video feedback to increase the accuracy of yoga poses. The interventions were assessed in a multiple baseline design across behaviors with 2 adults. Results showed that video self-evaluation increased the accuracy of all poses, and video feedback further increased the accuracy of 1 pose for 1 participant.
Motivations for Voluntary Environmental Management

This article examines the motivations for firms to participate in voluntary environmental programs and to adopt environmental management practices using data gathered from a survey conducted in 2005 of facilities located in Oregon operating in six industrial sectors. It is one of the first studies of voluntary environmental management to include small-, medium-, and large-sized facilities as well as to include both privately and publicly owned facilities. In particular, we examine the effects of both external factors such as regulatory, consumer, and investor pressures, and internal factors such as technical and resource capacity, in influencing voluntary environmental behavior. The intent is to describe potential influences that have implications for designing and implementing private and public policies that foster effective voluntary environmental management by firms. We find that larger facilities are more likely to participate in more voluntary environmental programs, but are likely to adopt more environmental management practices only if environmental issues are of significant concern to them. Presence of an R&D department stimulates the adoption of more environmental management practices, particularly if environmental issues are of significant concern to the facility, but does not have a statistically significant impact on participation in voluntary programs. We also find that while regulatory pressures are significant in motivating participation in voluntary programs and adoption of environmental management practices, competitive pressures are only important in motivating the former. Pressure from final good consumers or from investors in publicly traded facilities is not found to have a significant influence on voluntary environmental behavior of facilities in this study.
Naming in conditional discrimination and stimulus equivalence.

Using a matching-to-sample procedure, McIntire, Cleary, and Thompson (1987) taught monkeys the conditional relations A1-R1-A1-R1, A2-R2-A2-R2, A1-R1-B1-R1, A2-R2-B2-R2, B1-R1-C1-R1, and B2-R2-C2-R2, where the first and third terms in each relation refer to the sample and comparison stimuli, respectively, and the second and last terms refer to the emission of a distinctive pattern of responding. The subjects were then tested for the emergent relations A-C, C-A, B-A, C-B, and B-B, with the differential response produced by a given stimulus during training also emitted on test trials (e.g., A1-R1-C1-R1). The performances of both subjects were as accurate on the tested relations as they had been on the trained relations. The new relations were characterized as demonstrations of stimulus equivalence. However, the conditional discrimination literature shows that such training procedures generate control of comparison selection by the differential response patterns. Therefore, no emergent relations were demonstrated because all of the trained response-stimulus relations were preserved on test trials. This paper suggests that these procedures do not provide an appropriate analogy for the kind of emergent stimulus-stimulus relations exhibited by human subjects in equivalence studies and outlines a paradigm for assessing the relative influence of stimulus-stimulus and response-stimulus relations.
Microsatellite instability in breast cancer

Background: Microsatellites are short repetitive nucleotide sequences that, through mutation, can undergo either expansion or contraction. This novel mutational mechanism known as microsatellite instability may play a role in carcinogenesis. We investigated the incidence of microsatellite instability in a series of primary breast carcinoma surgical specimens.
Effects of mycotoxins in cultured kidney cells: Cytotoxicity of aflatoxin B1 in Madin-Darby and primary fetal bovine kidney cells

The cytotoxicity of aflatoxin B1, a fungal metabolite and an important food contaminant, was evaluated in an established cell line, Madin-Darby bovine kidney (MDBK) cells, and in primary fetal bovine kidney (PFBK) cells. Cells were grown in monolayers and treated with media containing AFB1 for 24 hr. Both culture systems were sensitive to the chemical; the PFBK cultures were approximately four times more susceptible to the cytotoxic effect. Cell multiplication decreased in both systems in long-term cultures. Adherence of MDBK cells was only slightly reduced at the toxic concentrations of the chemical. Electron microscopy revealed condensation of chromatin, separation of nuclei from the cytoplasm, cytoplasmic vacuolization, and loss of surface microvilli. Results indicated differential sensitivity of the two culture systems.
Critical Temperatures in Plasma Membrane Vesicles are Dependent on the Cell Cycle

Giant plasma membrane vesicles (GPMVs) isolated from RBL-2H3 cells appear uniform at physiological temperatures, contain coexisting liquid-ordered and liquid-disordered phases at low temperatures, and experience micron-sized critical fluctuations close to their critical temperature. We observe a broad distribution of critical temperatures in GPMVs isolated from a dish of seemingly identical cells even though each individual vesicle has a well defined critical temperature. In addition, we observe that the average transition temperature of GPMVs isolated from a population of cells is inversely proportional to the surface density of cells growing in the culture dish. Since it is known that cellular doubling times are reduced in more densely plated cells due to contact inhibition, we hypothesized that critical temperatures are linked to the cell cycle. To test this hypothesis, we isolated GPMVs from populations of cells synchronized using a double Thymidine block that arrests cells at the border between G1 and S phases. After Thymidine is removed from the culture media, cells proceed synchronously through one cell cycle and GPMVs are isolated at time-points corresponding to S, G2, M, and G1 phases. We find that critical temperatures are significantly elevated in the cell cycle phases that immediately preceding cell division (G2 and M) compared to the remainder of the cell cycle phases (G1 and S), consistent with our observations of higher overall transition temperatures in more rapidly dividing cells. We speculate that membrane heterogeneity arising from this critical point may play a role in cytokinesis or other processes vital for cell division. If this hypothesis is correct, it may suggest that biochemical perturbations that lower critical temperatures in GPMVs can be used to inhibit cellular proliferation, possibly providing a novel treatment strategy for some cancers.
Pattern-Based Composition and Analysis of Virtually Synchronized Real-Time Distributed Systems

Designing and verifying distributed protocols in a multi-rate asynchronous system is, in general, extremely difficult when the distributed computations require consistent input views, consistent actions and synchronized state transitions. In this paper, we address this problem and introduce a formal, complexity-reducing architectural pattern, called Multi-Rate PALS system, to support virtual synchronization in multi-rate distributed computations. The pattern supports a component to be virtually synchronized with other components in different instantiations of this pattern. We present an application of a hierarchical control system to show that the composition of these instantiations can be used to achieve desired system-level properties, such as distributed consistency and distributed coordination. We verify the logical synchronization guarantee of this pattern, which holds as long as the pattern assumptions are satisfied. We also discuss the correctness analysis necessary to validate these assumptions and provide a tool support to perform this analysis automatically on the AADL models.
Short-Term Thermal Resistance of Hexagrammid Eggs and Planktonic Larvae from Puget Sound

Abstract Eggs of the kelp greenling, Hexagrammos decagrammus; painted greenling, Oxylebius pictus; whitespotted greenling, H. stelleri; and larvae of these species and of lingcod, Ophiodon elongatus, were subjected to tests that simulated thermal stress associated with steam-powered electric stations using seawater for cooling in a once-through system. Ambient temperatures for holding the eggs and larvae were 8 C for the lingcod, 9 C for the kelp and whitespotted greenlings, and 13 C for the painted greenling. Embryos subjected to daily 4-hour exposures where temperature changes were gradual, as could occur with thermal plumes passing over egg nests, survived a maximum temperature of 22 C but not 24 C. Unfed larvae were subjected to conditions simulating passage through heat exchangers (held at elevated test temperatures for 10 or 20 minutes with an abrupt increase and decrease from ambient) or mixing with thermal plumes (held at test temperature 1–8 hours with temperatures gradually rising and decreasing...
Line Emission Sources for Concentration Measurements and Photochemistry

Abstract When a resonance line is absorbed in its own gas, measurements of this absorption can be used to derive a value of the product, n ƒ, of concentration of the absorber and ƒ-value of the transition. This line absorption process is also important in the study of fluorescence and photochemistry, where it is possible to produce atoms or molecules in a single quantum state without otherwise disturbing the system. The interpretation and success of these applications of line absorption depend critically on the shape of the line emitted by the light source. This is strongly influenced by the optical depth in the emitting region, and by the inevitable presence of a reversing layer through which the light must travel on its way out of the lamp. This paper presents a simple model which can be used to estimate the effects of these properties of the light source on the threshold and sensitivity of measurements of n ƒ, and on the power which can be delivered to absorbing atoms outside the lamp. Emphasis is on the general principles of lamp design and diagnosis, rather than on accurate description of a particular lamp.
Self-shielded Downflows in Core-Collapse Supernovae: Prospects for Laser Experiments

The core-collapse supernova mechanism pushes the frontiers of many aspects of physics and numerical modeling: equations of state for dense matter, neutrino cross sections and mixing, general relativity, and convection. The conditions in the convective layer driving the supernova explosion lead to both optically thin and optically thick regions. Thus, the convection is more complicated than the standard entropy-driven convection seen in a pot of boiling water. In this case, the convection is bathed in a radiation flow which heats the material and affects the convection. Radiation hydrodynamics, especially in the regime for which the optical depth is not extreme (τ ≈ 1), is not well understood. Fortunately, it may be possible to construct laboratory tests of this convection using laser experiments. In this paper, we summarize the neutrino-driven core-collapse supernova mechanism, describing its sensitivity to a range of physical parameters through a series of simulations. In particular, we notice that the varying results of the simulations may not be a difference in the neutrino heating rates alone, but rather a difference in the coupling of radiation with convection. This problem could be solved with an appropriately designed laser experiment.
Mechanism for nonequilibrium symmetry breaking and pattern formation in magnetic films

Magnetic thin films exhibit a strong variation in properties depending on their degree of disorder. Recent coherent x-ray speckle experiments on magnetic films have measured the loss of correlation between configurations at opposite fields and at the same field, upon repeated field cycling. We perform finite temperature numerical simulations on these systems that provide a comprehensive explanation for the experimental results. The simulations demonstrate, in accordance with experiments, that the memory of configurations increases with film disorder. We find that nontrivial microscopic differences exist between the zero field spin configuration obtained by starting from a large positive field and the zero field configuration starting at a large negative field. This seemingly paradoxical behavior is due to the nature of the vector spin dynamics and is also seen in the experiments. For low disorder, there is an instability which causes the spontaneous growth of linelike domains at a critical field, also in accord with experiments. It is this unstable growth, which is highly sensitive to thermal noise, that is responsible for the small correlation between patterns under repeated cycling. The domain patterns, hysteresis loops, and memory properties of our simulated systems match remarkably well with the real experimental systems.
Assisted reproductive technologies on the Web.

The rapid advance of the World Wide Web presents significant challenges for ensuring quality of health care information presented to a global audience. Using American Medical Association guidelines, Huang and co-authors have issued a report card for Society for Assisted Reproductive Technology–affiliated websites, indicating much room for improvement.
The electron-cyclotron maser instability as the source of solar type V continuum

In this paper, it is proposed that the electron-cyclotron (EC) maser instability can be the source of solar type V bursts. The propagation of electrons up an open field line is examined, and it is shown that the resultant distribution can be subject to the bump-in-tail (BIT) or the EC maser instabilities, or both. The characteristics of the emission from the BIT and EC maser instabilities when they are driven by such distributions are compared. It is proposed that type V bursts are produced by the coalescence of the upper hybrid waves produced by the maser instability, while type IIIs are produced by the BIT instability.
A Concentric Method for Mini-Micrografting Extensively Bald Patients

background A concentric method for mini-micrografting extensively bald patients is described. objective To demonstrate a method that effectively treats those extensively bald patients who wish to forgo any type of alopecia-reducing procedure posteriorly. method Initially the hairline is developed. Then the remaining posterior area of alopecia is gradually infringed upon in a concentric fashion. results Excellent results are accomplished with this method and, most importantly, the patient looks normal at any point during the treatments. If donor hair becomes depleted or the patient wishes no further treatments, he/she is left with a normal appearance. conclusion The method of performing mini-micrografts, starting from the front and moving posteriorly in a progressively concentric fashion, creates a very natural result at almost all phases of the surgical hair restoration.
Effects of long-term fenofibrate therapy on cardiovascular events in people with type 2 diabetes mellitus

The authors of the FIELD study conclude that the result of this large and scientifically rigorous study provides information to help guide clinicians on the future use of fenofibrate in patients with type 2 diabetes. They state the “results are likely to be of particular importance among patients without previous cardiovascular disease where both the prevention of non-fatal macrovascular events and microvascular complications are judged important.” I do not believe the results of the FIELD trial support an expanded role of fenofibrate therapy for patients with diabetes. To suggest we use fenofibrate as primary prevention in diabetic patients because a post hoc analysis of the FIELD study demonstrated no benefit in patients with known heart disease and modest benefit in patients without known heart disease is scientifically invalid and biologically implausible. To suggest we use fenofibrate to reduce microvascular disease will require a clinical trial designed to look at those specific endpoints. At present, there is no evidence to suggest that therapy with fenofibrate is superior to generic gemfibrozil. The clinical utility of fenofibrate in patients with more severe hypertriglyceridemia or in combination with statin therapy will remain to be demonstrated in a well-designed clinical trial.
Potency of authentic nitric oxide in inducing aortic relaxation.

Abstract The reported EC 50 of vasorelaxation for authentic nitric oxide (NO) is from the nM to μM range. The cause of this large difference is undetermined. In this study, NO electrodes were used to monitor the actual NO concentration in the organ chamber during the recording of the relaxation of rat aortic rings. It was demonstrated that both the O 2 concentration in the solution and the rate of stirring the solution markedly affected the actual NO concentration, while the vasorelaxation response to NO was also changed with the composition of the buffer solution. It was observed that the apparent EC 50 of aortic relaxation for authentic NO is 340 ± 40 nM and 81 ± 4 nM in the conventional organ chamber containing Krebs–Ringer buffer bubbled with a high content (95% O 2 + 5% CO 2 ) and a low content (20% O 2 + 5% CO 2 + 75% N 2 ) of O 2 gas mixture, respectively. The apparent EC 50 was further reduced to 45 ± 2 nM after the Krebs–Ringer buffer, a bicarbonate buffer, was replaced by a phosphate buffer solution bubbled with a low content of O 2 gas mixture (20% O 2 + 80% N 2 ) or with air. By using an organ chamber, which makes low concentrations of NO more stable in the solution, it was determined that the apparent EC 50 was 9.7 ± 0.4 nM and the threshold of NO concentration in dilating the aortas was ∼0.3 nM. This modified organ chamber will be useful for quantitatively measuring EC 50 of vasorelaxation for authentic NO under physiological and pathological conditions.
Molecular weight distribution effects on craze micromechanics

Abstract Quantitative transmission electron microscopy has been used to investigate the micromechanics of crazes in monodisperse and polydisperse polystyrene (PS). In the monodisperse PS, a large stress is observed at the craze tip, but this stress falls rapidly with distance behind the tip. In the polydisperse PS (or in blends in which a small percentage of monodisperse low molecular weight PS has been added to monodisperse high molecular weight PS) the stress at the craze tip is lower and falls much less rapidly with distance behind the craze tip. These changes are attributed to the effects of diluting the network of entangled high molecular weight chains with molecules that are too short to entangle. This dilution increases the molecular stress on the load bearing chains of the network, thus increasing the ease of craze fibrillation.
The suppressor-cell network in cancer (first of two parts).

IN the near future, new insights into the cellular control of immune reactivity may become important to physicians who manage patients with cancer. The objectives of this article are to provide an ...
Well singularities in reservoir simulation

In this study, the authors examine the problem of relating the computed solution at a well in reservoir simulation to the actual bottomhole pressure (BHP) and the related questions concerning determination of an effective radius for the computed pressured. They provide a mathematical analysis of this problem from a slightly different standpoint than that used elsewhere. Their approach provides further insight into the nature of the singularity, the extension to multisingularities, nonuniform grids, and the development of related approximation techniques for radially symmetric nonhomogenous problems. The authors present some fundamental new results based on the analysis.
TH‐C‐103‐07: Iterative Cone Beam CT Reconstruction On a Multi‐GPU Platform

Purpose: Compressed sensing‐based iterative cone beam CT (CBCT) reconstruction techniques can reconstruct CBCT from under‐sampled noisy projection data, allowing for imaging dose reduction. The long computation time prevents them from clinical applications. Although GPU dramatically improves computational efficiency, the computation time is still too long. The purpose of this project is to develop a reconstruction algorithm on a multi‐GPU platform. Methods: We have developed tight‐frame(TF) based CBCT reconstruction system on a workstation with 4 NVIDIA GTX590 GPUs. The algorithm iterates two steps: a conjugate gradient least square step (CGLS) enforcing projection condition and a regularization step improving image quality through TF domain. The first step involves frequent forward and backward x‐ray projections, which is accelerated by distributing tasks corresponding to different projection angles among GPUs. A parallel‐reduction algorithm is employed to accumulate data at all GPUs. The regularization step is achieved by having each GPU processing a sub‐volume. Boundary‐layer data between sub‐volumes are kept to maintain correct boundary conditions. A half‐fan reweighting technique is also invented to mitigate ring artifacts caused by imperfect scanning geometry. Results: Under the quad‐GPU system, the CGLS step, the regularization step are accelerated by 3.2∼3.6 times and 1.6∼2.6times compared to single‐GPU version, respectively. The overall speed‐up factor is 3.06∼3.51 times. As for the absolute time, it takes 0.41∼3.90 sec per iteration step depending on the image resolution and number of projections. Considering it usually takes about 10 iteration steps for the algorithm to achieve satisfactory image quality, the total reconstruction time ranges from a few seconds to up to 40 seconds. High quality CBCT images have been obtained in our system. The reweighing strategy also removes the ring artifacts in half‐fan cases. Conclusion: A TF‐based CBCT reconstruction on a multi‐GPU platform has been successfully developed. The achieved efficiency and image quality facilitates clinical implementations. This work is supported in part by NIH (1R01CA154747‐01), Varian Medical Systems through a Master Research Agreement, the Early Career Award from Thrasher Research Fund, and the University of California Lab Fees Research Program.
Voltage-insensitive Gating after Charge-neutralizing Mutations in the S4 Segment of Shaker Channels

Shaker channel mutants, in which the first (R362), second (R365), and fourth (R371) basic residues in the S4 segment have been neutralized, are found to pass potassium currents with voltage-insensitive kinetics when expressed in Xenopus oocytes. Single channel recordings clarify that these channels continue to open and close from −160 to +80 mV with a constant opening probability ( P o ). Although P o is low (∼0.15) in these mutants, mean open time is voltage independent and similar to that of control Shaker channels. Additionally, these mutant channels retain characteristic Shaker channel selectivity, sensitivity to block by 4-aminopyridine, and are partially blocked by external Ca 2+ ions at very negative potentials. Furthermore, mean open time is approximately doubled, in both mutant channels and control Shaker channels, when Rb + is substituted for K + as the permeant ion species. Such strong similarities between mutant channels and control Shaker channels suggests that the pore region has not been substantially altered by the S4 charge neutralizations. We conclude that single channel kinetics in these mutants may indicate how Shaker channels would behave in the absence of voltage sensor input. Thus, mean open times appear primarily determined by voltage-insensitive transitions close to the open state rather than by voltage sensor movement, even in control, voltage-sensitive Shaker channels. By contrast, the low and voltage-insensitive P o seen in these mutant channels suggests that important determinants of normal channel opening derive from electrostatic coupling between S4 charges and the pore domain.
School Discipline and Home Background

This study investigated the relationship between type of home and the frequency and severity of discipline cases reported to the principal's office in a selected secondary school. All discipline cases over a 6-year period were recorded by home type, frequency, and severity, and comparisons were then made. In only one home type (united home, mother not employed) was there found a smaller proportion of discipline cases than proportion of homes. Frequency and degree of severity of cases increased with home disruption.
A generalization of an integral of Ramanujan

This paper considers a generalization of an integral introduced by S. Ramanujan in his third notebook. Ramanujan’s integral is itself a version of the dilogarithm, $$Li_2(z) =-\int_{0}^{z}\frac{\log(1-x)}{x} \,\,dx.$$ We prove various functional equations and properties of the generalized integral.
Emergence of ‘Candidatus Liberibacter solanacearum’-Infected Seed Potato in Relation to the Time of Infection

Zebra chip (ZC) is a disease of potato, putatively caused by the vectorborne bacterium 'Candidatus Liberibacter solanacearum'. Although ZC has been a major concern due its significant negative impact on both potato yield and quality, its effect on seed potato sprouting has been the subject of recent evaluations. The present study was conducted to determine whether variation in emergence is affected by the infection duration of 'Ca. L. solanacearum'-infected seed potato prior to harvest. Furthermore, changes in pathogen detectability and titer levels in late-season-infected plants also were evaluated during and after cold storage. The rate of ZC-affected seed potato emergence following cold storage was not affected by the time of infection in the field, and the majority of ZC-infected tubers failed to sprout. Time to "seedling" emergence also was significantly longer in seed potato from plants infected ≥2 weeks before harvest. The small percentage of plants that emerged from ZC-affected seed potato produced stunted, nonvigorous plants that often died after a few weeks. The rate of successful 'Ca. L. solanacearum' detection increased during cold storage, suggesting a continued 'Ca. L. solanacearum'-tuber interaction postharvest. After tubers were removed from cold storage and held at room temperature, 'Ca. L. solanacearum' titer started to increase. Although none of the tubers from plants infected 1 week before harvest exhibited any disease symptoms or tested positive for 'Ca. L. solanacearum' at harvest, up to 38% of these tubers tested positive following placement at room temperature after cold storage. Results of this study suggest that the role of seedborne ZC in disease epidemiology is likely to be insignificant. Furthermore, the findings of this study emphasized the importance of continued control measures until at least a week before harvest, and highlighted the need for improved methods of 'Ca. L. solanacearum' detection at harvest, especially in tubers infected late in the season.
The flow downstream of a bifurcation of a flow channel for uniform flow distribution via cascade flow channel bifurcations

Abstract Uniform flow distribution is an important and fundamental issue to miscellaneous devices. The present work studied the details of flow in a channel with a fundamental structure—a symmetric bifurcation of one flow channel into two sub-channels. The structure is designated to split one flow into two streams of even flow rate. Key geometric design factors of the flow channel are investigated regarding the effect to the development of a symmetric velocity profile after the flow channel bifurcation, as the symmetric velocity profile is critical to the even split of the flow into two streams in the next stage of flow channel bifurcation. The study is based on both two-dimensional and three-dimensional CFD analyses. Both laminar and turbulent flows are investigated. Commercial CFD software ANSYS FLUENT® was used. The numerical treatment of convection terms in governing equations was based on the QUICK scheme, and the SIMPLE algorithm was used to treat the coupling of pressure and velocity fields. The obtained results are of great significance to the design of flow distributors using cascade flow channel bifurcations.
Investigation of vinyl phosphonic acid/hydroxylated α-Al2O3(0001) reaction enthalpies

Abstract The eleven ion vinyl phosphonic acid (VPA) molecule consists of a phosphorus ion that serves as a cationic anchor for two electron-rich functional groups, viz., a tripodal oxygen-rich base and vinyl hydrocarbon tail. Recent inelastic tunneling experiments have implied that VPA binds in a tridentate coordination though its base leaving the vinyl tail free to react with a resin in adhesive bonding applications. Using first-principles total energy calculations, the reaction enthalpies for bonding of a single VPA molecule to selected threefold sites on hydroxylated α-Al2O3(0 0 0 1) are investigated. Tridentate, bidentate and unidentate coordinations, both with and without liberated water molecules, are examined to determine if the tridentate coordination is favored over the others and the extent to which the VPA molecule is sensitive to surface site geometry. The electron localization function is used to examine the extent of covalent character between the P–O bonds that anchor the VPA fragment to the oxide surface. Some comments on the entropic contributions of the VPA and H2O molecules to the binding energetics are offered, along with a discussion of the effects of H2O placement on the oxide surface and aluminum alloying agents.
Cholesterol Crystal Embolization-Associated Renal Failure After Therapy With Recombinant Tissue-Type Plasminogen Activator

Abstract We report the occurrence of renal failure due to cholesterol crystal embolization following thrombolytic therapy with intravenous recombinant tissue-type plasminogen activator (t-PA). No invasive vascular procedure had been performed. Although there is one case report of cholesterol crystal embolization following t-PA therapy with only extrarenal manifestations (N Engl J Med 321:1270,1989), this is the first reported case of atheroembolic acute renal failure following t-PA therapy.
Changes in glycerolphosphate dehydrogenase activity during development of the grasshopper Schistocerca vaga

Abstract 1. 1. Extramitochondrial glycerolphosphate dehydrogenase ( l -glycerol-3-phosphate:DPN+ oxidoreductase, EC 1.1.1.8) was assayed in various tissues of the grasshopper Schistocerca vaga during the period from 3 days before to 8 days after the last molt. 2. 2. The specific activity, on protein basis, increase 8-fold in longitudinal dorsal flight muscles and 6-fold in the remaining pterothoracic flight muscles. 3. 3. The specific activity increases about 2-fold in two leg muscles (the flexor and extensor) and in fat body. 4. 4. The specific activity increases 6-fold in both mono- and bifunctional thoracic muscles. The former, the tergosternal muscles, are essentially only flight muscles. The latter, the thoracic coxal muscles, are active not only during adult flight but also during walking of the nymphs and adults. 5. 5. The relationship between tissue function and enzymitic development is discussed.