cssi/SciSciGPT-SciSciNet huggingface dataset:
Kinetics of unfolding and refolding of proteins. 3. Results for lysozyme.

Abstract The kinetics of the reversible denaturation of lysozyme by guanidine hydrochloride have been studied over a wide range of pH and denaturant concentration. The results contrast sharply with those observed for cytochrome c . The interconversion of native (N) and denatured (D) states is strictly first-order in both directions under most conditions, showing that no intermediate forms of any kind accumulate to a significant extent during the reaction. At one pH (pH 2.6) experiments were extended to extreme denaturant concentrations, and under these conditions kinetic intermediates were observed. Analysis by the procedures of the first paper of this series Ikai & Tanford 1973 showed that the principal intermediate observed at low denaturant concentration must be different from that observed at high denaturant concentration, and that both must be on the direct pathway from N to D. This suggests that the over-all reaction mechanism is of the form and this mechanism is able to account for all of the observed results. The intermediate X 1 which accumulates transiently in the renaturation reaction at low concentrations of guanidine hydrochloride is spectrally very similar to the native state, i.e. it is probably a highly ordered state, but most of the interactions between surface acidic and basic groups, which are responsible for the anomalous titration behavior of native lysozyme, do not yet exist in this state. It is probable that the difference between the kinetics of refolding of lysozyme and cytochrome c may be ascribed to the existence of disulfide cross-links in lysozyme, which were intact in these experiments. These cross-links greatly limit the possible pathways for folding and thus make it much less likely that incorrectly folded states on dead-end pathways are readily accessible.
GraSS: Graph Structure Summarization.

Large graph databases are commonly collected and analyzed in numerous domains. For reasons related to either space efficiency or for privacy protection (e.g., in the case of social network graphs), it sometimes makes sense to replace the original graph with a summary, which removes certain details about the original graph topology. However, this summarization process leaves the database owner with the challenge of processing queries that are expressed in terms of the original graph, but are answered using the summary. In this paper, we propose a formal semantics for answering queries on summaries of graph structures. At its core, our formulation is based on a random worlds model. We show that important graph-structure queries (e.g., adjacency, degree, and eigenvector centrality) can be answered efficiently and in closed form using these semantics. Further, based on this approach to query answering, we formulate three novel graph partitioning/compression problems. We develop algorithms for finding a graph summary that least affects the accuracy of query results, and we evaluate our proposed algorithms using both real and synthetic data.
Impact of a Yearlong Placement in a PDS on Teacher Interns' Dispositions and Abilities to Teach Middle School

As students prepare to enter college and the workforce, there has been a demand for them to be more independent, critical thinkers, innovative designers, and thoughtful collaborators. This preliminary study describes how a Professional Development School (PDS) partnership, between a middle school and a university, provides a more authentic teaching opportunity for middle grades teacher interns compared to the traditional, middle grades internship route. An authentic teaching experience provides a successful transition from "student to teacher" through a collaborative work environment; observing and developing the dispositions of an effective teacher; and learning the culture and structure of a school. The traditional middle grades internship route has been found to undermine the time needed to build relationships with students, cooperating teachers, and schools. The PDS partnership has alleviated this by securing a yearlong placement in one middle school leading to more confident, effective teachers prepared to engage the 21 st century learner.
Discrete-time rigid body attitude state estimation based on the discrete Lagrange-d'Alembert principle

Discrete-time estimation of rigid body attitude and angular velocity without any knowledge of the attitude dynamics model, is treated using the discrete Lagrange-d'Alembert principle. Using body-fixed sensor measurements of direction vectors and angular velocity, a Lagrangian is obtained as the difference between a kinetic energy-like term that is quadratic in the angular velocity estimation error and an artificial potential obtained from Wahba's function. An additional dissipation term that depends on the angular velocity estimation error is introduced, and the discrete Lagrange-d'Alembert principle is applied to the Lagrangian with this dissipation. An explicit first order and a symmetric second-order version of this discrete-time filtering scheme are also presented, with a discussion of their advantages. A numerical simulation comparing the performances of the second-order estimator and the first-order estimator is carried out.
The role of autophagy in intracellular pathogen nutrient acquisition

Following entry into host cells intracellular pathogens must simultaneously evade innate host defense mechanisms and acquire energy and anabolic substrates from the nutrient-limited intracellular environment. Most of the potential intracellular nutrient sources are stored within complex macromolecules that are not immediately accessible by intracellular pathogens. To obtain nutrients for proliferation, intracellular pathogens must compete with the host cell for newly-imported simple nutrients or degrade host nutrient storage structures into their constituent components (fatty acids, carbohydrates, and amino acids). It is becoming increasingly evident that intracellular pathogens have evolved a wide variety of strategies to accomplish this task. One recurrent microbial strategy is to exploit host degradative processes that break down host macromolecules into simple nutrients that the microbe can use. Herein we focus on how a subset of bacterial, viral, and eukaryotic pathogens leverage the host process of autophagy to acquire nutrients that support their growth within infected cells.
Laparoscopic Stoma Formation

A laparoscopic technique should be considered for all patients who are undergoing stoma formation because it is usually a simple and straight-forward procedure. Laparoscopic techniques appear to be safe and effective. They allow a thorough evaluation of associated intraabdominal pathology without causing extensive surgical trauma.
Efficacy of a geriatric oral health CD as a learning tool.

To better prepare professionals to meet the needs of older patients, a self-instructional computer module on geriatric oral health was previously developed. A follow-up study reported here tested the efficacy of this educational tool for improving student knowledge of geriatric oral care. A convenience sampling procedure was used. Sample size calculation revealed that fifty-six subjects were required to meet clinical and statistical criteria. Paired t-test addressed our hypothesis that use of the educational tool is associated with improvement in knowledge. Fifty-eight first-year dental students and nine third-year medical students completed the pre-intervention test and were given the CD-based educational tool. After seven days, all participants completed the post-intervention test. Knowledge of geriatric oral health improved among the sixty-seven students included in this study (p=0.019). When stratified on the basis of viewing the CD-ROM, the subgroup of thirty-eight students who reported not actually reviewing the CD-ROM had no change in their knowledge scores, while the subgroup of twenty-nine students who reported reviewing the CD had a significant improvement in test scores (p
Breakdown of the slow manifold in the Shallow-Water equations

Abstract Numerical solutions are obtained by implicit multigrid solvers for initial-value problems in the rotating Shallow-Water Equations (SWE) with spatially complex initial conditions. Companion solutions are also obtained with the Shallow-Water Balance Equations (SWBE), both to determine the initial conditions for the SWE and to provide a comparison solution that lies entirely on the slow, advective manifold. We make use of a control parameter (here the Rossby number, R) to regulate the degree of slowness and balance. While there are measurable discrepancies between the evolving SWE and SWBE solutions for all R, there is a distinct, spatially local breakdown both of the slow manifold in the SWE solution and in the closeness of correspondence between the SWE and SWBE solutions. This critical value for breakdown is only slightly smaller than the R values at which, first, the SWE evolution becomes singular (i.e., the fluid depth vanishes), or second, a consistent initial condition for the SWBE cannot be ...
Implementation of a Phase Only Spatial Light Modulator as an Atmospheric Turbulence Simulator at 1550 nm

Modeling and simulating atmospheric turbulence in a controlled environment have been a focus of interest for scientists for decades. The development of new technologies allows scientists to perform this task in a more realistic and controlled environment and provides powerful tools for the study and better understanding of the propagation of light through a nonstatic medium such as the atmosphere. Free space laser communications (FSLC) and studies in light propagation through the atmosphere are areas which constantly benefit from breakthroughs in technology and in the development of realistic atmospheric turbulence simulators, in particular (Santiago et al. 2011). In this paper, we present the results from the implementation of a phase only spatial light modulator (SLM) as an atmospheric turbulence simulator for light propagation in the short-wave infrared (SWIR) regime. Specifically, we demonstrate its efficacy for its use in an FSLC system, at a wavelength of 1550 nm.
Relationships among maternal-fetal attachment, prenatal depression, and health practices in pregnancy.

The purpose of this study was to investigate a conceptual model in which depression was proposed to have direct negative effects on positive health practices as well as indirect negative effects through maternal–fetal attachment (MFA). Participants were 252 adult pregnant women, between 20 and 40 weeks postgestation, who were recruited from five prenatal care sites. Data were collected using mailed self-report instruments measuring MFA, depression, health practices, and demographic and pregnancy information. Hierarchical regression was used to examine direct and indirect effects of depression, person characteristics (maternal age, pregnancy risk status, parity, ethnicity, education, income, marital status), and MFA on health practices. Results of the study supported the conceptual model. Higher education, lower parity, and being partnered predicted more positive health practices (p <05). After controlling for person characteristics, depression was found to be a significant predictor of MFA. Both depression and MFA were significant predictors of positive health practices but in opposite directions. Depression had a negative relationship and MFA a positive relationship with positive health practices. © 2001 John Wiley & Sons, Inc. Res Nurs Health 24: 203–217, 2001
The Relationship between Herzberg's Two-Factor Theory and Quality Improvement Implementation

ABSTRACTA study was conducted in nine organizations to investigate the relationship between the use of Herzberg's two-factor theory of job satisfaction and the successful implementation of quality improvement management (that is, total quality management, reengineering, quality improvement, etc.). Company respondents rated quality management implementation in their company based on six attributes: organization culture, customer focus, teamwork, problem solving, continuous improvement, and quality measurement. These same respondents were asked to describe a job-related event that was extremely satisfying and one that was dissatisfying. A relationship was found between the presence and use of Herzberg's motivators and quality improvement implementation success. Due to the variety of organizations included in the study, the conclusions would be applicable to most technical organizations.
Ultimate instability of exponential back-off protocol for acknowledgment-based transmission control of random access communication channels

When several users simultaneously transmit over a shared communication channel, the messages are lost and must be retransmitted later. Various protocols specifying when to retransmit have been proposed and studied in recent years. One protocol is "binary exponential back-off," used in the local area network Ethernet. A mathematical model with several idealizations (discrete time slots, infinite users, no deletions) is shown to be unstable in that the asymptotic rate of successful transmissions is zero, however small the arrival rate.
Reliability-Based Sensitivity Design of Gear Pairs with Non-Gaussian Random Parameters

Based on reliability design theory, by using the Edgeworth series method, and the sensitivity analysis method, the reliability sensitivity of the cylindrical gear pairs with non-Gaussian random parameters are extensively discussed and a numerical method for reliability sensitivity design is presented. The variation regularities of reliability sensitivity are obtained and the effects of design parameters on reliability of the cylindrical gear pairs are studied. The presented method provides the theoretic basis for reliability design of cylindrical gear pairs.
Nonexistence for the Kassoy problem

We prove that the Kassoy problem \[ (1)\qquad y'' - \frac{x}{2}y' + e^y - 1 = 0,\quad y(0) = \alpha ,\quad y'(0) = 0,\quad \alpha \in \mathbb{R}\] has no solution which has the asymptotic property \[ (2)\qquad y(x) \sim - 2\ln x + K\quad {\text{ as }} x \to \infty .\]
Feeding Dairy Cows in Drylot

Dairy cattle in southern California are fed almost exclusively in drylot. Proximity to the Los Angeles metropolitan area. and subsequent high land prices and taxes have been a major reason for this. Dairymen cannot afford to grow dairy feeds on land which can be used either for higher-value crops or, in some cases, for subdivision purposes. Consequently, ahnost all feeds, both forages and concentrates, used for dairy cattle in southern California are produced elsewhere and shipped into the area for feeding in drylot. Even in more rural areas of California drylot feeding predominates, and for many reasons. Land prices and taxes, although not so high as in the Los Angeles area, are still high for agricultural purposes. When land has been suitable, many former pastures have been converted to alfalfa hay, corn, cotton, or other higher-value crops because of the economic necessity to obtain higher returns per acre.
Feedback control strategies for a nonholonomic mobile robot using a nonlinear oscillator

Among control problems for mobile robots, point-to-point stabilization is the most challenging since it does not admit designs with smooth static state feedback laws. Stabilization strategies for mobile robots, and nonholonomic systems generally, are smooth, time-varying or nonsmooth, time-invariant. Time-varying control strategies are designed with umdamped linear oscillators but their fixed structure offer limited flexibility in control design. The central theme of this paper lies in use of nonlinear oscillators for mobile robot control. Large numbers of qualitatively different control strategies can be designed using nonlinear oscillators since stiffness and damping can be functions of robot states. We demonstrate by designing two fundamentally different controllers for two-wheeled mobile robot using two variants of a particular nonlinear oscillator. First controller is dynamic and generates smooth control action.
The Warburg effect in maize bundle sheath photosynthesis

Abstract Bundle sheath strands isolated from maize are capable of photosynthesizing glycolate in the presence of an inhibitor of glycolate oxidase. Glycolate synthesis is stimulated by high oxygen concentrations and suppressed by high levels of CO2. This data, together with the reversible oxygen inhibition of bundle sheath photosynthesis reported earlier [Ref. 6], demonstrates the occurrence of the Warburg effect in maize bundle sheath photosynthesis. These results also suggest a mechanism to account for the inhibition of photo-respiration in intact maize leaves.
Colonization with vancomycin-resistant enterococci in chronic hemodialysis patients

Abstract Vancomycin-resistant enterococcus (VRE) has been identified with increased frequency in dialysis populations, but the risk factors for VRE colonization are not well defined in hemodialysis patients. Patients from a university-affiliated outpatient dialysis center had surveillance stool or rectal cultures for VRE during April 1994 and January 1996. The combined cohort of 168 patients was followed-up for all-cause mortality, subsequent hospitalization, and VRE infection. Demographic and risk factor information, including age, gender, race, diabetes, coronary artery disease (CAD), and human immunodeficiency virus (HIV) infection, were collected on all patients. Sixteen patients had surveillance cultures grow vancomycin-resistant Enterococcus faecium or E faecalis (VREF), and nine additional patients had clinical cultures positive for VREF. The median follow-up time for patients with positive surveillance or clinical cultures for VREF was 421 days versus 423 days for those without VREF. Patients with positive surveillance cultures for VREF had less time on hemodialysis before screening (median = 207 days v 822 days; P
Transdermal bioavailability and first-pass skin metabolism: A preliminary evaluation with nitroglycerin

A model comprising six compartments, a systemic and presystemic compartment for nitroglycerin and each of its two dinitrate metabolites is presented to describe the interrelationships between plasma concentrations of the two metabolites and metabolism in skin after intravenous and transdermal ointment administration of nitroglycerin. Using a perfusion-limited pharmacokinetic model, the equation for the calculation of the fraction (F)of the dose of nitroglycerin systemically available from skin was derived independent of nitroglycerin plasma concentrations. Estimated Fvalues (0.68–0.76) are comparable to values reported in Rhesus monkeys (0.80–0.84). Simulated plasma concentration-time profiles were reasonably fitted to the observed concentrations of nitroglycerin and its two metabolites after transdermal administration. This preliminary model suggests that transdermal bioavailability for a drug metabolized in the skin can be reasonably estimated.
Calcium reconstitutes high rates of oxygen evolution in polypeptide depleted Photosystem II preparations

Abstract Exposure of highly resolved Photosystem II preparations to 2 M NaCl produces an 80% inhibition of oxygen-evolution activity concomitant with extensive loss of two water-soluble polypeptides (23 and 17 kDa). Addition of Ca2+ to salt-washed PS II membranes causes an acceleration in the decay of Z⨥, the primary donor to P-680+, and we show here that this acceleration is due to reconstitution of oxygen-evolution activity by Ca2+. Other cations (Mg2+, Mn2+, Sr2+) are much less effective in restoring oxygen evolution. On the basis of these observations we propose that Ca2+, perhaps in concert with the 23 kDa polypeptide, is an essential cofactor for electron transfer from the ‘S’-states to Z on the oxidizing side of PS II.
Insomnia in the geriatric patient

Insomnia in the geriatric patient is unique and complex, requiring a comprehensive and careful evaluation. Insomnia is the most common sleep complaint reported by persons > 60 years. It is defined as the inability to initiate or maintain sleep, and the etiology can be multifactorial. Insomnia in the geriatric patient may be due to a primary sleep disorder, such as obstructive sleep apnea, periodic limb movements in sleep, circadian rhythm disorders, or restless legs syndrome, or it may be secondary to underlying medical or psychiatric conditions, medication effects, or psychosocial factors. When insomnia becomes chronic, it may exacerbate medical and psychiatric illnesses. Insomnia can lead to excessive daytime sleepiness, which may result in disturbed intellect, impaired cognition, confusion, psychomotor retardation, or increased risk of injury, any of which can compromise the patient's quality of life and create social and economic burdens for caregivers. This article discusses the recommended diagnostic and treatment approaches that may be used by the clinician in treating the geriatric patient. Case studies are presented to illustrate diagnoses of insomnia and therapeutic interventions.
Pharmacological treatments that facilitate extinction of fear: relevance to psychotherapy.

A great deal is now known about the mechanisms of conditioned fear acquisition and expression. More recently, the mechanisms of inhibition of conditioned fear have become the subject of intensive study. The major model system for the study of fear inhibition in the laboratory is extinction, in which a previously fear conditioned organism is exposed repeatedly to the fear-eliciting cue in the absence of any aversive event and the fear conditioned response declines. It is well established that extinction is a form of new learning as opposed to forgetting or “unlearning” of conditioned fear, and it is hypothesized that extinction develops when sensory pathways conveying sensory information to the amygdala come to engage GABAergic interneurons through forms of experience-dependent plasticity such as long-term potentiation. Several laboratories currently are investigating methods of facilitating fear extinction in animals with the hope that such treatments might ultimately prove to be useful in facilitating exposure-based therapy for anxiety disorders in clinical populations. This review discusses the advances that have been made in this field and presents the findings of the first major clinical study to examine the therapeutic utility of a drug that facilitates extinction in animals. It is concluded that extinction is an excellent model system for the study of fear inhibition and an indispensable tool for the screening of putative pharmacotherapies for clinical use.
Intraductal Papillary Mucinous Adenocarcinoma of the Pancreas: Clinical Outcomes, Prognostic Factors, and the Role of Adjuvant Therapy.

Background: Intraductal papillary mucinous adenocarcinoma (IPMCs) occur more frequently in main-duct intraductal papillary mucinous neoplasms. Methods: Review of the literature. Results: The prognosis of IPMCs depends on its histopathological subtype: colloid IPMCs have superior survival rates mainly secondary to more favorable pathological features, whereas tubular IPMCs have survival outcomes similar to that of conventional pancreatic adenocarcinomas. The epithelial background plays an equally important role in defining the biology of IPMCs: gastric IPMC subtypes demonstrate an overall worse survival outcome when compared to intestinal, pancreatobiliary, and oncocytic subtypes. Lymph node involvement is one of the strongest predictors of survival in IPMC, with a decreasing overall survival as the lymph node ratio increases. There is little evidence to support adjuvant chemoradiation in patients with IPMC. Conclusion: Our current understanding of IPMC biology based on histopathological and epithelial background subtypes as well as clinicopathological predictors should influence patient counseling and selection for adjuvant therapy.
Experience with the reinforcer and the preference for earned rather than free reinforcers in rats

Manipulating experience with the reinforcer, through either home cage presentations of Noyes pellets or availability of the free reinforcer immediately prior to testing, attenuated the preference for earned as opposed to free reinforcers. Similarly, changing the reinforcer to one of a different flavor at testing increased the preference for the noncontingent reinforcer. These results are consistent with an interpretation of earned reinforcer preference which emphasizes the role of the reinforcer as a discriminative signal for further instrumental responding. It is suggested that the tendency to perform instrumental responses for reinforcers when free reinforcers are available can be explained in terms of traditional learning processes.
Fine‐structure superplasticity in materials

Abstract Superplastic forming is a viable net‐shape forming technology. It is an attractive manufacturing technique because it bypasses machining, joining and riveting, and reduces material waste. This paper reviews the history and progress in the field of superplasticity. Fundamental understandings, such as microstructural prerequisites and deformation mechanisms, and technological applications for superplasticity are discussed. A wide range of structural materials, including metals, intermetallics, and ceramics are presented. Some of the most recent advances, for example, high strain rate superplasticity, low temperature superplasticity, and the development of ultrafine‐grained materials for superplasticity are also described.
Race and acute abdominal pain in a pediatric emergency department.

OBJECTIVE: To investigate the demographic and clinical factors of children who present to the pediatric emergency department (ED) with abdominal pain and their outcomes. METHODS: A review of the electronic medical record of patients 1 to 18 years old, who presented to the Children’s Hospital of Pittsburgh ED with a complaint of abdominal pain over the course of 2 years, was conducted. Demographic and clinical characteristics, as well as visit outcomes, were reviewed. Subjects were grouped by age, race, and gender. Results of evaluation, treatment, and clinical outcomes were compared between groups by using multivariate analysis and recursive partitioning. RESULTS: There were 9424 patient visits during the study period that met inclusion and exclusion criteria. Female gender comprised 61% of African American children compared with 52% of white children. Insurance was characterized as private for 75% of white and 37% of African American children. A diagnosis of appendicitis was present in 1.9% of African American children and 5.1% of white children. Older children were more likely to be admitted and have an operation associated with their ED visit. Appendicitis was uncommon in younger children. Constipation was commonly diagnosed. Multivariate analysis by diagnosis as well as recursive partitioning analysis did not reflect any racial differences in evaluation, treatment, or outcome. CONCLUSIONS: Constipation is the most common diagnosis in children presenting with abdominal pain. Our data demonstrate that no racial differences exist in the evaluation, treatment, and disposition of children with abdominal pain.
Binding to retinoblastoma pocket domain does not alter the inter-domain flexibility of the J domain of SV40 large T antigen.

Abstract Simian Virus 40 uses the large T antigen (Tag) to bind and inactivate retinoblastoma tumor suppressor proteins (Rb), which can result in cellular transformation. Tag is a modular protein with four domains connected by flexible linkers. The N-terminal J domain of Tag is necessary for Rb inactivation. Binding of Rb is mediated by an LXCXE consensus motif immediately C-terminal to the J domain. Nuclear magnetic resonance (NMR) and small angle X-ray scattering (SAXS) were used to study the structural dynamics and interaction of Rb with the LXCXE motif, the J domain and a construct (N260) extending from the J domain through the origin binding domain (OBD). NMR and SAXS data revealed substantial flexibility between the domains in N260. Binding of pRb to a construct containing the LXCXE motif and the J domain revealed weak interactions between pRb and the J domain. Analysis of the complex of pRb and N260 indicated that the OBD is not involved and retains its dynamic independence from the remainder of Tag. These results support a ‘chaperone’ model in which the J domain of Tag changes its orientation as it acts upon different protein complexes.
Existence and a method for constructing canonical forms of linear time-varying control systems with scalar input

We suggest a method for constructing Frobenius canonical forms of linear time-varying systems of ordinary differential equations with scalar input. The method is based on the quasidifferentiability of the coefficients with respect to a specially constructed lower-triangular matrix. The use of quasidifferentiation rules permits substantially weakening the existence conditions for such forms.
The kinetics of glycerol and dimethyl sulfoxide in cultured leukemic and Burkitt lymphoma cells.

This experiment was designed to study the kinetics of glycerol and dimethyl sulfoxide (DMSO) in cultured cells of human leukemia and lymphoma at 0°C and 37°C. Quantitative photographic measurement of changes of cell diameter was used as assay of relative permeability. Movement of DMSO was generally found to be more rapid than that of glycerol. Movement of both agents was found to be more rapid at 37°C than at 0°C. Changes in cell diameter was marked with glycerol than with DMSO. Equilibration time of DMSO, as assayed by change in cell diameter at 0°C was approximately 15 to 20 minutes as contrasted with 20-25 minutes for glycerol.
Acute postnatal regulation of pyruvate carboxylase activity by compartmentation of mitochondrial adenine nucleotides

The total adenine nucleotide content of the mitochondrial matrix increases 3--4-fold within a few hours of birth in rat liver. This provides a mechanism for the acute postnatal regulation of pyruvate carboxylase, which is located in the matrix compartment and which requires ATP as a substrate. The sudden increase in pyruvate carboxylase activity is proposed to account for a rapid 4--5-fold increase in the gluconeogenic rate of the newborn rat.
Aging and the Segregation of Auditory Stimulus Sequences

This study aimed to clarify whether the age-related decline in selective attention widely reported in the literature can be attributed to a selective deficit in the segregation of relevant streams of sounds from irrelevant ones. Young and older individuals responded to infrequent deviant stimuli (targets) mixed with distractors in situations that facilitated perception of one or two streams of sounds. Both young and older adults showed the same degree of improvement in performance under conditions that promoted auditory streaming. However, in both listening conditions young subjects were faster and more accurate than older subjects in responding to target tones. Thus, it appears that agerelated declines in auditory selective attention cannot be attributed to a selective deficit in the segregation of auditory sequences, but occur in a subsequent stage of processing such as response selection and/or execution.
Fixed-dose combination of sitagliptin and metformin for the treatment of type 2 diabetes

Janumet(TM,) a fixed dose combination of sitagliptin/metformin HCL manufactured by Merck Pharmaceuticals, has received US Food and Drug Administration approval for treatment of patients with type 2 diabetes, that are inadequately controlled, either by sitagliptin or metformin alone or together in free-dose combination form. Sitagliptin, an inhibitor of the enzyme DDP-4, assists patients with type 2 diabetes mellitus to achieve glycemic control. It has been shown to be safe and effective at 100 mg daily doses. The effect of giving sitagliptin in combination with metformin is thought to have a complimentary and possibly additive effect on glycemic control.
Anti-tobacco socialization in homes of African-American and white parents, and smoking and nonsmoking parents

Abstract Purpose: To examine parental perceptions and behaviors with regard to teen smoking, comparing African-American and white parents, and those who did and did not smoke. Methods: Focus groups consisting of African-American and white parents who smoked provided initial in-depth information. A computer-assisted telephone survey of a biracial sample of 311 parents of children ages 8 to 17 years provided more generalizable information regarding parental beliefs and behaviors. Results: Nearly 50% of households either allowed teen smoking, had no ground rules, or had set restrictive rules but never communicated them to the children. Compared to white parents, African-American parents felt more empowered to affect their children's behaviors and were more likely to actively participate in anti-tobacco socialization within the home (all p values p p = 0.02), but were more likely to believe that childhood tobacco use is inevitable ( p = 0.01). Conclusions: Many parents are not engaged in anti-tobacco socialization in the home. Differences in the degree of parental participation may contribute to the variance in smoking prevalence between African-American and white children.
R1: a rule-based configurer of computer systems

R1 is a program that configures VAX-11/780 computer systems. Given a customer's order, it determines what, if any, modifications have to be made to the order for reasons of system functionality and produces a number of diagrams showing how the various components on the order are to be associated. The program is currently being used on a regular basis by Digital Equipment Corporation's manufacturing organization. R1 is implemented as a production system. It uses Match as its principal problem solving method; it has sufficient knowledge of the configuration domain and of the peculiarities of the various configuration constraints that at each step in the configuration process, it simply recognizes what to do. Consequently, little search is required in order for it to configure a computer system.
Synthesis of a molecular Mo2Fe6S9 cluster with the topology of the PN cluster of nitrogenase by rearrangement of an edge-bridged Mo2Fe6S8 double cubane.

The structures of the P cluster and cofactor cluster of nitrogenase are well-defined crystallographically. They have been obtained only by biosynthesis; their chemical synthesis remains a challenge. Synthetic routes are sought to the P cluster in the PN state in which two cuboidal Fe3S3 units are connected by a μ6-S atom and two Fe−(μ2-SCys)−Fe bridges. A reaction scheme affording a Mo2Fe6S9 cluster in molecular form having the topology of the PN cluster has been devised. Reaction of the single cubane [(Tp)MoFe3S4Cl3]1- with PEt3 gives [(Tp)MoFe3S4(PEt3)3]1+ (2), which upon reduction with BH4- affords the edge-bridged all-ferrous double cubane [(Tp)2Mo2Fe6S8(PEt3)4] (4) (Tp = tris(pyrazolylhydroborate(1−)). Treatment of 4 with 3 equiv of HS- produces [(Tp)2Mo2Fe6S9(SH)2]3- (7) as the Et4N+ salt in 86% yield. The structure of 7 is built of two (Tp)MoFe3(μ3-S)3 cuboidal fragments bridged by two μ2-S atoms and one μ6-S atom in an arrangement of idealized C2 symmetry. The cluster undergoes three one-electron ...
HIV-tat induces formation of an LRP–PSD-95– NMDAR–nNOS complex that promotes apoptosis in neurons and astrocytes

HIV infection of the central nervous system can result in neurologic dysfunction with devastating consequences in AIDS patients. NeuroAIDS is characterized by neuronal injury and loss, yet there is no evidence that HIV can infect neurons. Here we show that the HIV-encoded protein tat triggers formation of a macromolecular complex involving the low-density lipoprotein receptor-related protein (LRP), postsynaptic density protein-95 (PSD-95), N-methyl-d-aspartic acid (NMDA) receptors, and neuronal nitric oxide synthase (nNOS) at the neuronal plasma membrane, and that this complex leads to apoptosis in neurons negative as well as positive for NMDA receptors and also in astrocytes. Blockade of LRP-mediated tat uptake, NMDA receptor activation, or neuronal nitric oxide synthase significantly reduces ensuing neuronal apoptosis, suggesting that formation of this complex is an early step in tat toxicity. We also show that the inflammatory chemokine, CCL2, protects against tat toxicity and inhibits formation of the complex. These findings implicate the complex in HIV-induced neuronal apoptosis and suggest therapeutic targets for intervention in the pathogenesis of NeuroAIDS.
Relative azimuth inversion by way of damped maximum correlation estimates

Horizontal seismic data are utilized in a large number of Earth studies. Such work depends on the published orientations of the sensitive axes of seismic sensors relative to true North. These orientations can be estimated using a number of different techniques: SensOrLoc (Sensitivity, Orientation and Location), comparison to synthetics (Ekstrom and Busby, 2008), or by way of magnetic compass. Current methods for finding relative station azimuths are unable to do so with arbitrary precision quickly because of limitations in the algorithms (e.g. grid search methods). Furthermore, in order to determine instrument orientations during station visits, it is critical that any analysis software be easily run on a large number of different computer platforms and the results be obtained quickly while on site. We developed a new technique for estimating relative sensor azimuths by inverting for the orientation with the maximum correlation to a reference instrument, using a non-linear parameter estimation routine. By making use of overlapping windows, we are able to make multiple azimuth estimates, which helps to identify the confidence of our azimuth estimate, even when the signal-to-noise ratio (SNR) is low. Finally, our algorithm has been written as a stand-alone, platform independent, Java software package with a graphical user interface for reading and selecting data segments to be analyzed.
Sublimation enthalpies at 298.15 K using correlation gas chromatography and differential scanning calorimetry measurements

The sublimation enthalpies of 17 hydrocarbons are obtained by combining the technique of correlation gas chromatography (CGC), to evaluate vaporization enthalpies at 298.15 K, and differential scanning calorimetry (DSC) to measure fusion enthalpies. Vaporization enthalpies at 298.15 K obtained by CGC are compared to values measured directly from vapor pressure measurements at temperatures above the melting point by adjusting the experimental vaporization enthalpy for the effects of temperature. Vaporization enthalpies obtained by these two methods agree within3877 J mol ˇ1 . Fusion enthalpies are similarly adjusted for temperature. Sublimation enthalpies, obtained by combining temperature adjusted fusion, and vaporization enthalpies agree within2580 J mol ˇ1 . The sublimation enthalpies of azulene and 1,8-cyclotetradecadiyne are also measured by head-space analysis resulting in values of 76880 and 94348 J mol ˇ1 at 298.15 K, respectively. # 1998 Elsevier Science B.V.
Discovery of Cushing’s Syndrome After Bariatric Surgery: Multicenter Series of 16 Patients

The aim of this study is to demonstrate the importance of considering Cushing’s syndrome (CS) as a potential etiology for weight gain and metabolic complications in patients undergoing bariatric surgery (BS). This is a retrospective chart review case series of patients (n = 16) with CS from five tertiary care centers in the USA who had BS. Median age at BS surgery was 35.5 years (median 2.5 years between BS and CS surgery). CS was not identified in 12 patients prior to BS. Four patients had CS surgery prior to BS, without recognition of recurrent or persistent CS until after BS. Median body mass index (BMI) values before BS, nadir after BS, prior to surgery for CS, and after surgery for CS were 47, 31, 38, and 35 kg/m2, respectively. Prior to BS, 55 % of patients had hypertension and 55 % had diabetes mellitus. Only 17 % had resolution of hypertension or diabetes mellitus after BS. CS may be under-recognized in patients undergoing BS. Testing for CS should be performed prior to BS in patients with features of CS and in post-operative BS patients with persistent hypertension, diabetes mellitus, or excessive weight regain. Studies should be conducted to determine the role of prospective testing for CS in subjects considering BS.
Identification of the peptide-binding motif recognized by the pigtail macaque class I MHC molecule Mane-A1*082:01 (Mane A*0301)

Rhesus and pigtail macaques have proven to be valuable animal models for several important human diseases, including HIV, where they exhibit similar pathology and disease progression. Because rhesus macaques have been extensively characterized in terms of their major histocompatibility complex (MHC) class I alleles, their demand has soared, making them increasingly difficult to obtain for research purposes. This problem has been exacerbated by a continued export ban in place since 1978. Pigtail macaques represent a potential alternative animal model. However, because their MHC class I alleles have not been characterized in detail, their use has been hindered. To address this, in the present study, we have characterized the peptide binding specificity of the pigtail macaque class I allele Mane-A1*082:01 (formerly known as Mane A*0301), representative of the second most common MHC class I antigen detected across several cohorts. The motif was defined on the basis of binding studies utilizing purified MHC protein and panels of single amino acid substitution analog peptides, as well as sequences of peptide ligands eluted from Mane-A1*082:01. Based on these analyses, Mane-A1*082:01 was found to recognize a motif with H in position 2 and the aromatic residues F and Y, or the hydrophobic/aliphatic residue M, at the C-terminus. Finally, analysis of the binding of a combinatorial peptide library allowed the generation of a detailed quantitative motif that proved effective in the prediction of a set of high-affinity binders derived from chimeric SIV/HIV, an important model virus for studying HIV infection in humans.
Why do expectations models of the term structure fail

Abstract This paper provides evidence that the apparent rejection of the expectations theory for data on nominal Treasury bill yields is primarily due to the failure of market participants to forecast inflation in a consistent manner over horizons of different length.
Gas Turbine Retrofit With Modern Control Systems

The rapid advances in technology of control systems precipitated by the development of microprocessors has made retrofit of older type controls an attractive alternative for many gas turbine owners. High reliability, enhanced operator interface, and optimized maintenance planning are some of the tangible benefits that can accrue from these retrofits. The design and features of the new equipment are discussed, and some of the complexities of changing out control systems and their associated instrumentation in field units are reviewed.Copyright © 1985 by ASME
Effect of time of dosing on the disposition of oral cibenzoline.

Single oral doses of cibenzoline were administered to eight healthy volunteers on two different occasions, once at 8.00 am and once at 10.00 pm, in a randomized crossover design with at least one week separating treatments. A fast was maintained for 12 hours prior to and for 2 hours after the morning dose and the subjects did not lie down for at least 12 hours after dosing. A standard dinner was eaten 3 hours prior to the evening dose, and a fast was maintained for 10 hours after dosing; the subjects laid down 2 hours after dosing for at least 6 hours. Blood was collected at specific times for 72 hours and the total volume of urine voided was collected through 72 hours. Cibenzoline concentrations in plasma and urine were measured by HPLC. Cibenzoline absorption was slower in 7 of the 8 volunteers following the evening dose relative to the morning dose. Mean +/- S.D. tmax for the evening dose was 2.6 +/- 0.5 hours compared to 1.7 +/- 0.8 for the morning dose. The corresponding mean +/- S.D. Cmax following the morning dose was 446 +/- 124 ng ml-1 compared to 402 +/- 114 ng ml-1 after the evening dose. The mean +/- S.D. AUC was 3328 +/- 1101 ng . h . ml-1 after the morning dose and 3561 +/- 1430 ng . h . ml-1 after the evening dose. The harmonic mean half-life was 7.4 hours after both treatments. These data indicated that the total amount of drug absorbed and the elimination rate constant of the drug had not varied between treatments.(ABSTRACT TRUNCATED AT 250 WORDS)
Field strength and temperature studies of electroluminescent powders in dielectric media

Electroluminescent cells are constructed by dispersing a copper-activated zinc sulfo-selenide phosphor powder in a thermoplastic dielectric matrix. The resulting sheet material is observed to glow when an alternating electric field is applied. The light produced is not continuous, but flickers with twice the applied frequency, dropping to zero between flashes.The electric field in the phosphor particles can be calculated if the particles are assumed to be spheres; however, it is first necessary to determine their dielectric constant. This is done by comparing the dielectric constant of the phosphor-plastic aggregate with that of the clear plastic. The results of these calculations show that, for a variety of plastic matrix materials having different dielectric constants, the brightness of electroluminescence depends only on the electric field in the phosphor particles.A cell having a matrix of polystyrene was used in studying the brightness of electroluminescence versus temperature. This material has a relatively small temperature coefficient of dielectric constant. Only a small change of brightness was observed in a temperature range from −100°C to +50°C. This fact suggests that the mechanism responsible for electroluminescence does not depend on thermal activation.
Robots as Weapons in Just Wars

This essay analyzes the use of military robots in terms of the jus in bello concepts of discrimination and proportionality. It argues that while robots may make mistakes, they do not suffer from most of the impairments that interfere with human judgment on the battlefield. Although robots are imperfect weapons, they can exercise as much restraint as human soldiers, if not more. Robots can be used in a way that is consistent with just war theory when they are programmed to avoid using force against all but the most clearly hostile targets. However, the essay also cautions against using robots for counterinsurgency because they may alienate people in the contested area and lead to an escalation of hostilities.
Representational difference analysis: finding the differences between genomes

Representational difference analysis (RDA) is an efficient method for finding the differences between complex genomes. The numerous applications of RDA include the cloning of probes for the detection of genetic lesions in cancer, the identification of sequences from the genomes of unknown pathogens and the rapid isolation of polymorphic markers linked to a trait without the use of pre-existing genetic maps.