cssi/SciSciGPT-SciSciNet huggingface dataset:
Effect of a proton pump inhibitor on postprandial gastric volume, emptying and symptoms in healthy human subjects: a pilot study.

Summary Background In consensus guidelines, proton pump inhibitors (PPIs) are recommended for the treatment of functional dyspepsia. It is unclear whether PPIs change gastric volume or emptying. Aim To assess the effect of a PPI, rabeprazole, on gastric volume and emptying and postprandial symptoms. Methods In a double-blind, parallel-group placebo-controlled trial, 13 healthy participants were randomized to rabeprazole, 20 mg b.d., or placebo. On day 3, fasting gastric volume was measured using intravenous 99mTc-pertechnate and single photon emission computed tomography (SPECT). After the last dose of study medication, an 111In-chloride egg meal (300 kcal) was ingested, and postprandial gastric volume and emptying were measured by SPECT. Symptom ratings using a visual analogue scale (fullness, nausea, bloating, abdominal pain, aggregate score) were obtained at baseline and 15, 30, 45, 60 and 75 min postprandially. Group comparisons were performed using Mann–Whitney rank sum test. Results There were no statistically significant differences in gastric volume or emptying in the two groups. However, there was a borderline increase in gastric volume with rabeprazole compared with placebo. Rabeprazole treatment reduced aggregate postprandial symptoms, particularly fullness, 30 min after the meal (P = 0.01). Conclusions In healthy participants, rabeprazole, 20 mg b.d., did not significantly change gastric emptying, but reduced symptoms and had a borderline effect on gastric volume postprandially. The mechanism of reduced postprandial symptoms with a PPI requires further study.
Comparing the cross polar cap potentials measured by SuperDARN and AMIE during saturation intervals

[1] Assimilative Mapping of Ionospheric Electrodynamics (AMIE) and Super Dual Auroral Radar Network (SuperDARN) are two commonly used techniques to measure cross polar cap potential (ΦPC). In this study, I compare ΦPC inferred from AMIE with that inferred from SuperDARN during saturation intervals. Measurements from Defense Meteorological Satellite Program (DMSP) and polar cap (PC) index are also used to help estimate true ΦPC. Seven saturation events in 2000 were selected. For each event, I ran the AMIE software driven by magnetometer data only, by magnetometer data and SuperDARN data, and by SuperDARN data only. Then I compared ΦPC obtained from AMIE with that from SuperDARN. I found that: (1) ΦPC inferred from SuperDARN is significantly lower than that inferred from other techniques including AMIE when ΦPC is large (e.g., greater than 150 kV); (2) ΦPC inferred from AMIE with SuperDARN input is much higher than ΦPC inferred from SuperDARN; (3) ΦPC inferred from AMIE with magnetometer input tends to give the same results as that inferred from AMIE with magnetometer and SuperDARN input; (4) ΦPC inferred from AMIE with magnetometer input is, in general, in agreement with ΦPCinferred from AMIE with SuperDARN input. It is suggested that reason for the low values of SuperDARN-derived ΦPC during saturation intervals is that the SuperDARN algorithm to compute ΦPC from measurements is not applicable to such intervals.
A Novel Design Of Composite Water Turbine Using CFD

This paper presents computational investigation of a novel design of composite material axial water turbine using Computational Fluid Dynamics (CFD). Based on three-dimensional numerical flow analysis, the flow characteristics through the water turbine with nozzle, wheel and diffuser are predicted. The extract power and torque of a composite water turbine at different rotating speeds were calculated and analyzed for a specific flow speed. The simulation results show that using nozzle and diffuser can increase the pressure drop across the turbine and extract more power from available water energy. These results provide a fundamental understanding of the composite water turbine, and this design and analysis method is used in the design process.
Space is continuous—continuous-displacement treatment of phase-separating diagrams

The conventional crystal statistics treats permutation of species placed at lattice points of a fixed lattice. The present work removes the fixed lattice restriction and allows displacement of atoms from lattice points of a fixed reference lattice. This extension responds to the need of taking into account local lattice distortion caused by size differences of species in alloys. Because the continuous displacement concept had not been studied before in the cluster variation method formulation, the current series started with the two-dimensional lattices. This work is the first in the series to venture into the three-dimensional lattices. We use the pair approximation for fcc and work out phase diagrams of phase-separating systems. The step-by-step formulation of the theory is presented. Numerical computations on a number of model systems show asymmetrical phase diagrams. Various future applications are discussed.
Effect of Chemical and Microbial Amendments on Ammonia Volatilization from Composting Poultry Litter

Research has shown that aluminum sulfate (alum) and phosphoric acid greatly reduce ammonia (NH3) volatilization from poultry litter; however, no studies have yet reported the effects of these amendments on field-scale composting of poultry litter. The objectives of this study were to (i) evaluate NH3 volatilization from composting litter by measuring both NH3 volatilization and changes in total nitrogen (N) in the litter and (ii) evaluate potential methods of reducing NH3 losses from composting poultry litter. Poultry litter was composted for 68 d the first year and 92 d the second year. Eleven treatments were screened in Year 1, which included an unamended control, a microbial mixture, a microbial mixture with 5% alum incorporated into the litter, 5 and 10% alum rates either surface-applied or incorporated, and 1 and 2% phosphoric acid rates either surface-applied or incorporated. Treatments in Year 2 included an unamended control, a microbial mixture, alum (7% by fresh wt.), and phosphoric acid (1.5% by fresh wt.). Alum and phosphoric acid reduced NH3 volatilization from composting poultry litter by as much as 76 and 54%, respectively. The highest NH3 emission rates were from microbial treatments each year. Compost treated with chemical amendments retained more initial N than all other treatments. Due to the cost and N loss associated with composting poultry litter, composting is not economical from an agronomic perspective compared with the use of fresh poultry litter.
ISDN implementation for a point-to-multipoint subscriber radio system

Abstract This paper will discuss the use of a point-to-multipoint subscriber radio system in both a line/loop extension and intelligent network node configuration to support basic rate ISDN subscribers' terminal equipment. Considerations involved in each type of implementation are included in the discussion as well as the concept of an open structure which will enable the line/loop configuration to be used as a basis for an intelligent node implementation.
Absorption of Disodium Cromoglycate from the Rat Lung: Evidence of Carrier Transport

1. Pulmonary absorption studies in the rat with 0–01–100 mM solutions of disodium cromoglycate (DSCG) indicated that absorption occurred in part by a saturable, carrier-type transport process and in part by diffusion.2. Carrier transport became saturated at DSCG concentrations greater than 50 mM, and the transport maximum was estimated to be 92 μg/h under the conditions of these experiments.3. Transport was inhibited by certain other organic anions including phenol red, chlorphenol red, benzylpenicillin and cephalothin. Moreover, DSCG inhibited the carrier transport of phenol red.4. The results suggested that DSCG and phenol red share a common transport process for their absorption from the lung.
A 24-hour comparison of serum growth hormone concentrations in patients with heart failure versus healthy controls.

Study Objective. To compare endogenous serum growth hormone concentrations over a 24-hour period in patients with chronic heart failure (CHF) and matched controls. Design. Prospective, 24-hour, endogenous concentration comparison. Setting. Hospital research center. Patients. Eight evaluable patients with nonischemic dilated cardiomyopathy and 10 healthy control subjects, matched for age and sex. Intervention. Over a 24-hour period, blood was drawn from the study participants every 20 minutes for determination of growth hormone. Measurements and Main Results. For each patient, the area under the concentration-time curve from time 0–24 hours (AUC0–24), maximum concentration (Cmax), and minimum concentration (Cnadir) of growth hormone were determined. The AUC0–24 and Cmax were 74% (p<0.05) and 62% (p<0.05) lower in patients with CHF than in controls, respectively. The Cnadir for all participants was 0 μg/L. Variability in growth hormone concentrations over the 24 hours was considerable for all study participants. Conclusions. Growth hormone concentrations are suppressed over a 24-hour period in patients with CHF versus healthy controls. Variability in levels throughout the day suggests that a single point evaluation cannot be used to determine deficiency or abundance of growth hormone.
A correlation between the sedimentation coefficient of deoxyribonucleic acid and its paper chromatographic migration

Abstract A method for the paper chromatographic examination of DNA is described. The rate of migration of DNA on paper has been found to be related to the sedimentation coefficient. Accordingly, a rough estimate of the sedimentation coefficient of DNA may be obtained without recourse to ultracentrifugation.
FLUID AND CALORIC INTAKE IN INFANTS WITH ACUTE RENAL FAILURE

Despite lack of any quantitative fluid and dietary data, it is widely claimed that patients with oliguric acute renal failure (ARF) are in a catabolic state because they receive inadequate calories, given the fluid constraints imposed by therapy of this condition. We studied this problem by carefully analyzing fluid and calorie balance in 10 consecutive infants with ARF (urine output <20 cc/kg/day) secondary to major surgical procedures. Each patient received parenteral hyperalimentation from the onset of oliguria. A specially constructed fluid balance sheet was used to aid in the fluid calculation, and the caloric content of wound and chest tube drainage was estimated by analysis of protein content. The caloric value of blood given or lost, and of various protein infusates was also estimated. Serum and urinary albumin, transferrin, and IgG levels were serially measured during the first 3 days of oliguria. The mean net volume of fluid received was 45 ± 14 cc/kg/day. The mean weight gain during the period of oliguria (median time 7 days) was 13% above preoperative weight. There was a large variation in the net number of calories received with the mean value being 34 ± 17 cal/kg/day. Significant reductions in serum levels of albumin occurred in 7, transferrin in 6, and IgG in 2 patients despite minimal absolute urinary protein loss. These data suggest that a catabolic state is present in ARF that can be largely explained by inadequate calorie intake.
THE NUMERICAL SIMULATION OF VARIABLE-PROPERTY REACTING-GAS DYNAMICS: NEW INSIGHTS AND VALIDATION

ABSTRACT A large number of numerical algorithms have been reported to solve the Euler equations of motion for a variety of mechanical and aerospace engineering applications. Based on a review of the past and current history of these solvers, a MUSCL-based solver that uses Hancock's predictor-corrector method incorporating Roe's approximate Riemann solver was found to be the most efficient second-order-accurate numerical method to solve the Euler equations. This method was subsequently extended to account for variable properties and then extensively validated for the effects of friction, heat transfer, variable area, and chemical kinetics.
Research on Divorce: Continuing Trends and New Developments

Research on divorce during the past decade has focused on a range of topics, including the predictors of divorce, associations between divorce and the well-being of children and former spouses, and interventions for divorcing couples. Methodological advances during the past decade include a greater reliance on nationally representative longitudinal samples, genetically informed designs, and statistical models that control for time-invariant sources of unobserved heterogeneity. Emerging perspectives, such as a focus on the number of family transitions rather than on divorce as a single event, are promising. Nevertheless, gaps remain in the research literature, and the review concludes with suggestions for new studies.
Postoperative inotrope and vasopressor use following CABG: outcome data from the CAPS-care study.

Outcomes following coronary artery bypass grafting (CABG) continue to improve, despite the fact that the recipient patient population is older and has more comorbidities, compared to previous years. Advances in perioperative processes of care continue to play an important role in these improvements.1, 2 However, while many perioperative processes of care have been defined and linked to improvements in outcomes, data is lacking with regards to inotrope and vasopressor use for treatment of low cardiac output syndrome (LCOS) in the early postoperative period following CABG. Several clinical studies have examined the factors associated with the development of LCOS and the subsequent need for inotropic support.3–5 Commonly defined as low cardiac output (confidence interval [CI] <2.5) with evidence of end-organ dysfunction such as low urine output (<0.5mL/kg/hr), LCOS is associated with increased morbidity and mortality following CABG6 and is known to increase length of stay, resource use, and overall costs.5 The multitude of positive vasoactive agents enlisted alone or in combination for the management of LCOS include phosphodiesterase inhibitors (amrinone, milrinone), antidiuretic hormone analogues (vasopressin), pure alpha adrenergic agonists (phenylephrine), and both natural (epinephrine, dopamine) and synthetic (dobutamine, dopexamine) catecholamines.7 While individual physiological effects have been outlined, insufficient clinical data exist to guide general practice patterns for use of these agents following CABG. Clinicians generally balance perceived physiologic benefits against perceived risks, including induced arrhythmias or decreased peripheral, renal, and bypass graft perfusion.8 While some clinicians/institutions routinely administer inotropic agents to all patients undergoing CABG, others administer these agents selectively to patients with either authentic or anticipated LCOS. Without evidence-based guidance, variation by clinician and institution is not only expected, but has been demonstrated in large multicenter registries.7, 9, 10 This study seeks to address the present gap in knowledge regarding optimal pattern of application of inotropic agents during the critical recovery period following CABG.
Primary Sjogren syndrome: clinical and immunopathologic features

Primary Sjogren syndrome is an autoimmune condition in which dry eyes (keratoconjunctivitis sicca) and dry mouth (xerostomia) result from lymphocytic infiltration of lacrimal and salivary glands. Clinical and laboratory features of 60 primary Sjogren syndrome patients seen at our clinic during the past three years are presented. These patients illustrate the wide spectrum of extraglandular features that may occur as a result of lymphoid infiltration of lung, kidney, skin, stomach, liver, and muscle. They further emphasize the difficulty in classifying a patient as primary or secondary Sjogren syndrome (ie, sicca symptoms associated with systemic lupus erythematosus, rheumatoid arthritis, or scleroderma), particularly early in the disease course. As an initial step in understanding the pathogenesis, the lymphocytes that infiltrate the salivary glands and lymph nodes were characterized by using monoclonal antibodies that recognize distinct lymphocyte subsets and by using in vitro functional assays. These studies have demonstrated that affected tissues have infiltrates of T cells with helper/inducer activity and with a high frequency of "activation antigens." The immunohistologic techniques are useful in differentiating "benign" and "pseudolymphoma" lesions (both due predominantly to T cells) from non-Hodgkin lymphoma (usually due to B-cell infiltrates). Although there is no "cure" for primary Sjogren syndrome patient's symptoms may be significantly improved by measures aimed at prevention of ocular and dental complications and by the recognition of extraglandular features that may be amenable to specific treatment.
The enthalpies of solution and formation of ammonia

Abstract The standard enthalpy of solution of gaseous ammonia in water to form the non-ionized solute was found to be ΔHsolno(298.15 K) = − (8448 ± 15) calth mol−1 by direct solution calorimetry. The results were compared with values from other sources, and the value So(NH4+, aq, 298.15 K) = (26.45 ± 0.13) calth K−1 mol−1 was calculated from adjuvant data on the solution and ionization processes. The enthalpy of formation of NH3(g) was recalculated from a third-law analysis of measurements on the equilibrium: 2 3 H 2 (g) + 1 2 N 2 (g) = NH 3 (g) . A set of best values for some of the thermodynamic properties of the ammonia species is suggested.
Anti-inflammatory effect of albuterol enantiomers during respiratory syncytial virus infection in rats

Every year in the United States, respiratory syncytial virus (RSV) infections in infants and young children cause more than 120,000 hospitalizations, often complicated by the need for mechanical ventilation; yet no effective therapy is currently available for this disease. We showed previously that RSV infection is associated with neurogenic inflammation in the lower respiratory tract. In the present study, we sought to determine whether aerosolized β2-receptor agonists inhibit neurogenic-mediated albumin extravasation in the airways of RSV-infected, mechanically ventilated rats, and to compare the anti-inflammatory effects of racemic albuterol ((RS)-albuterol) to its individual enantiomeric components (R)-albuterol and (S)-albuterol. Albumin extravasation evoked by sensorineural stimulation with capsaicin was inhibited only partially by 0.63 mg (RS)-albuterol, and higher doses had minimal incremental effects. In contrast, the anti-inflammatory effect of (R)-albuterol was already larger at the lowest dose of 0.31 mg, and complete inhibition of neurogenic exudation was observed at higher doses. (S)-albuterol had no significant inhibitory effect up to 1.25 mg, and had only partial inhibitory effect at higher doses. The anti-inflammatory effect of (R)-albuterol was independent from the expression of substance P neurokinin 1 receptors, suggesting a direct vascular effect. Our data show that (R)-albuterol has a much stronger inhibitory effect on neurogenic inflammation in RSV-infected airways when aerosolized in enantiomerically pure form, rather than in a racemic mixture with (S)-albuterol. Based on these data, we speculate that (R)-albuterol may be more effective than other adrenergic agents in the management of bronchiolitis. Pediatr Pulmonol. © 2005 Wiley-Liss, Inc.
Development of molecularly targeted therapies in biliary tract cancers: Reassessing the challenges and opportunities

Biliary tract cancers (BTCs), which encompass intra- and extrahepatic cholangiocarcinomas as well as gallbladder carcinomas, are a genetically diverse collection of cancers. Most patients with BTC will present with unresectable or metastatic disease. Although the standard systemic chemotherapy approaches are emerging, the prognosis remains poor. Development of molecularly targeted therapies in advanced BTC remains challenging. Recent early-stage clinical trials with targeted therapies appear promising, although the relationships between subsets of patients with positive responses to therapy and tumor genetics remain unexplored. Here we summarize the relevant molecular pathogenesis, recent and ongoing clinical trials with targeted agents, and the key issues in clinical trial design in BTC.
Formal information support systems for domestic violence victims

Survivors of domestic violence (DV) seek information on many issues under stressful and even dangerous circumstances. Numerous agencies use multiple information formats to structure segments of formal information systems in support of these crime victims. The effort of e-government to make full use of the Internet's potential for interactive, substantive information provision is a key feature of this system. Many users rely on this formal system in times of crisis as well as during the often lengthy, incremental movement toward safety. Nevertheless, no post-Internet examination of the nature or efficacy of the system has been conducted in the United States. This study examines the information needs and concerns of DV survivors and those who seek to assist them, as well as the nature of this formal system. Using a two-stage combination of interviews and questionnaires, the study involves survivors, safe-house directors, police officers, health care workers, public library reference staff, and social service directors in several demographically diverse Texas cities. A web-site analysis of the relevant e-government and safe-house sites in each city extends the work. This study constitutes the first regional analysis in the U.S. of post-Internet formal information systems for the support of DV victims.
Topologically reliable approximation of composite Bézier curves

We present an efficient method of approximating a set of mutually nonintersecting simple composite planar and space Bezier curves within a prescribed tolerance using piecewise linear segments and ensuring the existence of a homeomorphism between the piecewise linear approximating segments and the actual nonlinear curves. Equations and a robust solution method relying on the interval projected polyhedron algorithm to determine significant points of planar and space curves are described. Preliminary approximation is obtained by computing those significant points on the input curves. This preliminary approximation, providing the most significant geometric information of input curves, is especially valuable when a coarse approximation of good quality is required such as in finite element meshing applications. The main approximation, which ensures that the approximation error is within a user specified tolerance, is next performed using adaptive subdivision. A convex hull method is effectively employed to compute the approximation error. We prove the existence of a homeomorphism between a set of mutually non-intersecting simple composite curves and the corresponding heap of linear approximating segments which do not have inappropriate intersections. For each pair of linear approximating segments, an intersection check is performed to identify possible inappropriate intersections. If these inappropriate intersections exist, further local refinement of the approximation is performed. A bucketing technique is used to identify the inappropriate intersections, which runs in O(n) time on the average where n is the number of linear approximating segments. Our approximation scheme is also applied to interval composite Bezier curves.
Tyrosine phosphorylation of G protein alpha subunits by pp60c-src

Abstract A number of lines of evidence suggest that cross-talk exists between the cellular signal transduction pathways involving tyrosine phosphorylation catalyzed by members of the pp60c-src kinase family and those mediated by guanine nucleotide regulatory proteins (G proteins). In this study, we explore the possibility that direct interactions between pp60c-src and G proteins may occur with functional consequences. Preparations of pp60c-src isolated by immunoprecipitation phosphorylate on tyrosine residues the purified G-protein alpha subunits (G alpha) of several heterotrimeric G proteins. Phosphorylation is highly dependent on G-protein conformation, and G alpha(GDP) uncomplexed by beta gamma subunits appears to be the preferred substrate. In functional studies, phosphorylation of stimulatory G alpha (G alpha s) modestly increases the rate of binding of guanosine 5'-[gamma-[35S]thio]triphosphate to Gs as well as the receptor-stimulated steady-state rate of GTP hydrolysis by Gs. Heterotrimeric G proteins may represent a previously unappreciated class of potential substrates for pp60c-src.
Term premia and the maturity composition of the Federal debt: new evidence from the term structure of interest rates

This paper models bond term premia empirically in terms of the maturity composition of the federal debt and other observable economic variables in a time-varying framework with potential regime shifts. We present regression and out-of sample forecasting results demonstrating that information on the age composition of the Federal debt is useful for forecasting term premia. We show that the multiprocess mixture model, a multi-state time-varying parameter model, outperforms the commonly used GARCH model in out-of-sample forecasts of term premia. The results underscore the importance of modelling term premia, as a function of economic variables rather than just as a function of asset covariances as in the conditional heteroscedasticity models. Copyright © 2001 John Wiley & Sons, Ltd.
Laue crystal structure of Shewanella oneidensis cytochrome c nitrite reductase from a high-yield expression system.

The high-yield expression and purification of Shewanella oneidensis cytochrome c nitrite reductase (ccNiR) and its characterization by a variety of methods, notably Laue crystallography, are reported. A key component of the expression system is an artificial ccNiR gene in which the N-terminal signal peptide from the highly expressed S. oneidensis protein "small tetraheme c" replaces the wild-type signal peptide. This gene, inserted into the plasmid pHSG298 and expressed in S. oneidensis TSP-1 strain, generated approximately 20 mg crude ccNiR per liter of culture, compared with 0.5-1 mg/L for untransformed cells. Purified ccNiR has nitrite and hydroxylamine reductase activities comparable to those previously reported for Escherichia coli ccNiR, and is stable for over 2 weeks in pH 7 solution at 4 °C. UV/vis spectropotentiometric titrations and protein film voltammetry identified five independent one-electron reduction processes. Global analysis of the spectropotentiometric data also allowed determination of the extinction coefficient spectra for the five reduced ccNiR species. The characteristics of the individual extinction coefficient spectra suggest that, within each reduced species, the electrons are distributed among the various hemes, rather than being localized on specific heme centers. The purified ccNiR yielded good-quality crystals, with which the 2.59-A-resolution structure was solved at room temperature using the Laue diffraction method. The structure is similar to that of E. coli ccNiR, except in the region where the enzyme interacts with its physiological electron donor (CymA in the case of S. oneidensis ccNiR, NrfB in the case of the E. coli protein).
Formation Damage by Fines Migration Including Effects of Filter Cake, Pore Compressibility, and Non-Darcy Flow - A Modeling Approach to Scaling From Core to Field

The transport of fine particles in formations has been recognized as the major cause of formation damage. In this study, a two-phase, multi-species formation damage model was developed. The model allows for filter cake formation on the sand face, particle mobilization and retention in pore spaces, particle transfer at fluid-fluid interface, and porosity and permeability alteration. The effects of non-Darcy flow, relative premeabilities, capillary pressure, and wettability of fine particles and pore surfaces on two-phase flow formation damage were considered. A one-dimensional numerical simulator was constructed based on the model. The model was validated using published laboratory data. Parameters involving the formation damage model were also determined using the laboratory data. With respect to field applications, the extent and degree of formation damage around the wellbore and the associated skin factor were predicted by implementing the model in radial flow. This study serves to enhance the understanding of formation damage due to particulate processes. This model is a useful tool for analyzing formation damage in laboratory core tests and simulate and predict formation damage in field operations.
The ethical standard of care.

I find a good deal to support in the position put forward by Dr. Edmund Pellegrino in his 1987 paper, “Toward a Reconstruction of Medical Morality,” which has been republished in this issue (Pelleg...
Synchrotron Studies of Phase Transformations

Material properties are dependent upon atomic arrangement. The structure provides a basis for calculation and for the interpretation of experiment. In the Earth context, mineral structure is composition, pressure and temperature sensitive, and changes in the phases present cause profound changes in properties. Examples include the relationship between sound velocities (elasticity) and structure as a function of depth in the Earth (Chen et al. 1999, Li et al. 1998, Liebermann and Li 1998, Parise et al. 1998). The selective sorption of ions and isotopes on mineral surfaces, and on particular faces on one growing surface, are excellent examples of how sorption is controlled by atomic arrangement (Reeder 1991, 1996). It is desirable therefore that material properties and structure be studied together, and if possible under the conditions of operation for that material. For the geosciences, this means studies of crystal structure and physical properties at elevated temperatures and pressures. For the solid state physics, chemistry and planetary science communities, it might also include high pressure/low temperature investigations of magnetic structures. Access to synchrotron radiation has made these types of studies routine. To address topical concepts and issues, beamlines have become more versatile and more easily reconfigured. This has decreased the cycle time between blue-sky concept and reality, and it will radically alter the mineral chemistry and mineral physics cultures, as national facilities are now firmly established at the cutting edge of solid state research (Hemley 1999). The science enabled by these facilities is impossible to reproduce in the home laboratory, as is the culture of interdisciplinary activity, interdependence between groups of collaborators, and speedy application of basic X-ray and neutron physics to applied problems. This mode of science is strange to many. The change however, is inevitable and will continue to gather momentum. The advent of …
Surface tiling with differential topology

A challenging problem in computer-aided geometric design is the decomposition of a surface into four-sided regions that are then represented by NURBS patches. There are various approaches published in the literature and implemented as commercially available software, but all fall short in either automation or quality of the result. At Raindrop Geomagic, we have recently taken a fresh approach based on concepts from Morse theory. This by itself is not a new idea, but we have some novel ingredients that make this work, one being a rational notion of hierarchy that guides the construction of a simplified decomposition sensitive to only the major critical points.
The binding of hemoglobin to membranes of normal and sickle erythrocytes

Abstract The binding of hemoglobins A, S, and A 2 to red cell membranes prepared by hypotonic lysis from normal blood and blood from persons with sickle cell anemia was quantified under a variety of conditions using hemoglobin labelled by alkylation with 14 C-labelled Nitrogen Mustard. Membrane morphology was examined by electron microscopy. Normal membranes were found capable of binding native hemoglobin A and hemoglobin S in similar amounts when incubated at low hemoglobin: membrane ratios, but at high ratios hemoglobin saturation levels of the membranes increased progressively for hemoglobin A, hemoglobin S and hemoglobin A 2 , respectively, in order of increasing electropositivity. Binding was unaffected by variations in temperature (4–22 °C) and altered little by the presence of sulfhydryl reagents, but was inhibited at pH levels above 7.35; disrupted at high ionic strength; and dependent on the ionic composition of the media. These findings suggest that electrostatic, but not hydrophobic or sulfhydryl bonds are important in membrane binding of the hemoglobin under the conditions studied. An increased retention of hemoglobin in preparations of membranes from red cells of patients with sickle cell anemia (homozygote S) was attributable to the dense fraction of homozygote S red cells rich in irreversibly sickled cells, and the latter membranes had a smaller residual binding capacity for new hemoglobin. This suggests that in homozygote S cells which have become irreversibly sickled cells in vivo, there are membrane changes which involve alteration and/or blockade of hemoglobin binding sites. These findings support the notion that hemoglobin participates in the dynamic structure of the red cell membrane in a manner which differs in normal and pathological states.
Oncogenes in neural tumors

Abstract Tumors result in part from somatic mutations that convert normal cellular genes (proto-oncogenes) to oncogenes. A powerful approach to understanding tumorigenesis is first to identify oncogenes, and then to determine how the products of these genes differ functionally from their counterparts in normal cells. In this article we will focus on the possible role of such genes in tumors of the nervous system and in normal neural development.
Langmuir-Blodgett assembly of graphite oxide single layers.

Single-layer graphite oxide can be viewed as an unconventional type of soft material and has recently been recognized as a promising material for composite and electronics applications. It is of both scientific curiosity and technical importance to know how these atomically thin sheets assemble. There are two fundamental geometries of interacting single layers: edge-to-edge and face-to-face. Such interactions were studied at the air−water interface by Langmuir−Blodgett assembly. Stable monolayers of graphite oxide single layers were obtained without the need for any surfactant or stabilizing agent, due to the strong electrostatic repulsion between the 2D confined layers. Such repulsion also prevented the single layers from overlapping during compression, leading to excellent reversibility of the monolayers. In contrast to molecular and hard colloidal particle monolayers, the single layers tend to fold and wrinkle at edges to resist collapsing into multilayers. The monolayers can be transferred to a substr...
Determination of the gas-phase acidities of halogen-substituted aromatic compounds using the silane-cleavage method

The gas-phase acidities of halogen-substituted aromatic compounds have been determined in a flowing afterglow-triple quadrupole apparatus with use of the silane cleavage method developed by DePuy and co-workers [C. H. DePuy, S. Gronert, S. E. Barlow, V. M. Bierbaum and R. Damrauer, J. Am. Chem. Soc., 111, 1968 (1989)]. In this method the relative fields of siloxide ion products produced in reactions of OH - with trimethylsilyl- or phenyldimethylsilyl-substituted aromatic compounds are correlated with the difference in gas-phase acidity of the accompanying neutral products. Acidities are reported for different ring-positions in fluoro-, chloro- and bromobenzene, chloro- and bromonaphthalene and benzyl chloride. Excellent precision is achieved in most cases, with assigned uncertainties less than 2-3 kcal/mol. Good agreement is obtained between the acidities determined with use of two different types of silane precursor. Halogen-substitution increases the gas-phase acidities of benzene and naphthalene by similar amounts (13-14 kcal/mol). The effects on different ring-positions in benzene and naphthalene are shown to be primarily inductive in nature, falling-off by a consistent 2.5-3.5 kcal/mol per bond separating the acidic site from the halogen-bearing carbon in the chlorine and bromine-substituted systems. Larger effects are evident in the positional acidities of fluorobenzene. The meta and para position acidities of halobenzenes are shown to be linearly correlated with the acidities of the corresponding meta and para halophenols, haloanilines and halotoluenes
Retention of lead in the rat

This study compares the relative effectiveness of different diets, therapeutic agents, and chelation in reducing the elevated tissue concentrations of lead in rats. Young male rats were given lead by exposure to drinking water containing 350 ppm of lead as lead acetate. After four weeks of exposure, the source of lead was removed, surviving rats randomized among eight groups, and subjected to one of the following: (1) terminated (positive control-1); (2) returned to the previous exposure to lead (positive control-2); (3) given the control diet (positive control-3); (4) increased minerals (diet); (5) increased ascorbic acid (diet) and thiamine (injection); (6) increased cellulose (diet); (7) ethylenediaminetetraacetic acid (EDTA) (injection); and (8) dimercaptosuccinic acid (DMSA) (injection). After six weeks, the experiment was terminated, the following tissues were harvested, and the lead concentrations determined: blood, brain, calvaria (flat bone), femur (long bone), kidney, and liver. Histopathological examinations of kidneys were provided, and the hematocrit and hemoglobin were measured. The highest lead concentrations were found in the femurs of rats following ten weeks exposure. All groups receiving lead had significantly higher lead concentrations than the controls. None of the diets produced a significant reduction in the concentration of lead in the tissues when compared with the positive control-3 (the leaded rats not receiving treatment). A reduction in the lead concentration in the brain and liver was obtained by chelation.
Bisimulation relations for dynamical, control, and hybrid systems

The fundamental notion of bisimulation equivalence for concurrent processes, has escaped the world of continuous, and subsequently, hybrid systems. Inspired by the categorical framework of Joyal, Nielsen and Winskel, we develop novel notions of bisimulation equivalence for dynamical systems as well as control systems. We prove that these notions can be captured by the abstract notion of bisimulation as developed by Joyal, Nielsen and Winskel. This is the first unified notion of system equivalence that transcends discrete and continuous systems. Furthermore, this enables the development of a novel and natural notion of bisimulation for hybrid systems, which is the final goal of this paper.
The Information Capacity of the Human Fingertip

An order-of-magnitude upper bound is placed on the information channel capacity for vibrotactile stimulation of human fingertips. Results are presented which suggest an order-of-magnitude limit of 100 bit/s. This limit is compared to previously published figures for similar limits in the human ear and eye, showing a progression of 102: 104: 106, respectively.
The Mechanics of Ground Deformation Precursory to Dome‐Building Extrusions at Mount St. Helens 1981–1982

Detailed monitoring at Mount St. Helens since 1980 has enabled prediction of the intermittent eruptive activity (mostly dome growth) with unprecedented success. During 1981 and 1982, accelerating deformation of the crater floor around the vent (including radial cracks, thrust faults, and ground tilt) was the earliest indicator of impending activity. Numerical experiments using the finite element method to model the mechanics of the crater floor show that all deformation features can be explained by a uniform shear-stress boundary condition along the conduit wall. The magnitude of the shear stress required to match observed displacements (1–7 MPa) is inversely proportional to the conduit diameter (estimated to be 25–100 m). The most probable source of this shear stress is the flow of viscous magma up the conduit and into the lava dome. We propose a model in which the accelerating deformation, beginning as much as 4 weeks before extrusions, is caused by the increasing velocity of ascending magma in the conduit. This model is examined by using deformation data of the dome before four extrusions in 1981 and 1982 to estimate the volumetric flow rate through the conduit. This flow rate and an estimate of the effective viscosity of the magma enable calculation of an ascent velocity and an applied shear stress that, again, depend on the conduit diameter. The results of these calculations are consistent with the finite element experiments and show that the proposed model is feasible. In light of this model, events observed just before or near the time extrusions began, such as reversals of ground tilt direction from outward to inward and the sudden decrease in the number of shallow earthquakes, may indicate an abrupt decrease of shear stress in the conduit. This could be explained by a decrease in either the ascent velocity, or the effective viscosity of the magma ascending through the shallow conduit, or both, near the time of extrusion. Precursory deformation like that measured at Mount St. Helens should be observable at similar volcanoes elsewhere because it is caused by the fundamental process of magma ascent.
The Effect of Collective Bargaining on Teacher Pay: A Review of the Evidence

This analysis examines the effect of collective bargaining on teacher pay in the light of an early theory of teacher bargaining power. Trends in the salaries of teachers are discussed, and the methodology and results of major studies are critically analyzed. The problems with existing research are noted and suggestions for researchers and all partisans are presented.
Fuzzy Sets and Their Operations

For a long time it has been recognized that an exact description of many real life physical situations may be virtually impossible. This is due to the high degree of imprecision involved in real world situations. Zadeh, in his seminal papers [Zadeh, 1965; and 1968], proposed fuzzy set theory as the means for quantifying the inherent fuzziness that is present in ill-posed problems (which by many accounts are the majority of the real life problems in decision making). Fuzziness is a type of imprecision which may be associated with sets in which there is no sharp transition from membership to nonmembership [Bellman and Zadeh, 1970]. Examples of fuzzy sets are classes of objects (entities) characterized by such adjectives as large, small, serious, simple, approximate, etc. [Bellman and Zadeh, 1970].
The pineapple eye Gene Is Required for Survival of Drosophila Imaginal Disc Cells

Each ommatidium of the Drosophila eye is constructed by precisely 19 specified precursor cells, generated in part during a second mitotic wave of cell divisions that overlaps early stages of ommatidial cell specification. Homozygotes for the pineapple eye mutation lack sufficient precursor cells due to apoptosis during the period of fate specification. In addition development is delayed by apoptosis during earlier imaginal disc growth. Null alleles are recessive lethal and allelic to l(2)31Ek; heteroallelic combinations can show developmental delay, abnormal eye development, and reduced fertility. Mosaic clones autonomously show extensive cell death. The pineapple eye gene was identified and predicted to encode a novel 582-amino-acid protein. The protein contains a novel, cysteine-rich domain of 270 amino acids also found in predicted proteins of unknown function from other animals.
Phylogenetic evidence for an ancient rapid radiation of Caribbean sponge-dwelling snapping shrimps (Synalpheus).

Abstract A common challenge in reconstructing phylogenies involves a high frequency of short internal branches, which makes basal relationships difficult to resolve. Often it is not clear whether this pattern results from insufficient or inappropriate data, versus from a rapid evolutionary radiation. The snapping shrimp genus Synalpheus, which contains in excess of 100 species and is a prominent component of coral-reef faunas worldwide, provides an example. Its taxonomy has long been problematic due to the subtlety of diagnostic characters and apparently widespread variability within species. Here we use partial mt COI and 16S rRNA sequences and morphological characters to reconstruct relationships among 31 species in the morphologically well-defined gambarelloides species group, a putative clade of obligate sponge associates that is mostly endemic to the Caribbean and contains the only known eusocial marine animals. Analysis of the combined data produced a single tree with good support for many terminal clades and for relationships with outgroups, but poor support for branches near the base of the gambarelloides group. Most basal branches are extremely short and terminal branches are long, suggesting a relatively ancient, but rapid radiation of the gambarelloides group. This hypothesis is supported by significant departure from a null model of temporally random cladogenesis. Calibration of divergence times among gambarelloides-group species using data from three geminate pairs of Synalpheus species separated by the isthmus of Panama suggests a major radiation between ∼5 and 7 Mya, a few My before final closure of the Panamanian seaway during a period of spreading carbonate environments in the Caribbean; a second, smaller radiation occurred ∼4 Mya. This molecular evidence for a rapid radiation among Caribbean marine organisms in the late Miocene/early Pliocene is strikingly similar to patterns documented from fossil data for several other Caribbean reef-associated invertebrate taxa. The similar patterns and timing of cladogenesis evidenced by molecular and fossil data for different Caribbean and East Pacific taxa suggests that the radiation involved a wide range of organisms, and strengthens the case that poor basal resolution in the gambarelloides group of Synalpheus reflects a real evolutionary phenomenon. The rapid radiation also helps explain the historical difficulty of diagnosing species in Synalpheus.
Growth phase-dependent invasion of Pseudomonas aeruginosa and its survival within HeLa cells

Clinical isolates of Pseudomonas aeruginosa are classified into invasive and noninvasive (cytolytic) strains. In a noninvasive PA103 background, ExoS and ExoT have recently been shown to function as anti-internalization factors. However, these two factors seemed not to have such a function in an invasive strain PAK background. In this study, using HeLa tissue culture cells, we observed that the internalization of invasive strain PAK is dependent on its growth phases, with the stationary-phase cells internalized about 100-fold more efficiently than the exponential-phase cells. This growth phase-dependent internalization was not observed in the noninvasive PA103 strain. Further analysis of various mutant derivatives of the invasive PAK and the noninvasive PA103 strains demonstrated that ExoS or ExoT that is injected into host cells by a type III secretion machinery functions as an anti-internalization factor in both types of strains. In correlation with the growth phase-dependent internalization, the invasive strain PAK translocates much higher amount of ExoS and ExoT into HeLa cells when it is in an exponential-growth phase than when it is in a stationary-growth phase, whereas the translocation of ExoT by the noninvasive strain PA103 is consistently high regardless of the growth phases, suggesting a difference in the regulatory mechanism of type III secretion between the two types of strains. Consistent with the invasive phenotype of the parent strain, an internalized PAK derivative survived well within the HeLa cells, whereas the viability of internalized PA103 derivative was dramatically decreased and completely cleared within 48 h. These results indicate that the invasive strains of P. aeruginosa have evolved the mechanism of intracellular survival, whereas the noninvasive P. aeruginosa strains have lost or not acquired the ability to survive within the epithelial cells.