cssi/SciSciGPT-SciSciNet huggingface dataset:
Dissection of the pH Dependence of Inhibitor Binding Energetics for an Aspartic Protease: Direct Measurement of the Protonation States of the Catalytic Aspartic Acid Residues†,‡

The catalytic activity and inhibitor binding energetics of enzymes are often pH-dependent properties. Aspartic proteases comprise an important class of enzyme targets for structure-based drug design. We have performed a complete thermodynamic study of pepstatin binding to plasmepsin II, an aspartic proteinase found in Plasmodium falciparum, using isothermal titration calorimetry and circular dichroism. Thermodynamic parameters (ΔG, ΔH, ΔCp, and ΔS) were measured as functions of both pH and temperature. In the pH range from 4.5 to 7.0, pepstatin binding is accompanied by proton transfer between the solvent and the complex. We used thermodynamic proton linkage theory to derive both the pH-independent binding energetics for pepstatin and the number and pKa values of ionizable residues whose pKa values change during ligand binding. These residues were identified as the two catalytic aspartates, with pKas of 6.5 and 3.0, and His 164, with a pKa of 7.5, based on the three-dimensional structure of the pepstatin−...
Thermally reversible cross-links in a healable polymer: Estimating the quantity, rate of formation, and effect on viscosity

Abstract The conversion behavior of 2MEP4FS, a polymer with thermally reversible Diels–Alder cross-links, is modeled. A processing method is developed to create small, homogeneous prepolymer samples. The glass transition temperature of the prepolymer is estimated using temperature modulated differential scanning calorimetry and equated with the conversion of the polymer. Comparing the measured energy with the literature and computational estimates, the fully cured polymer appears to have a large portion of its moieties unreacted. An autocatalytic model is considered to approximate the reaction rate of 2MEP4FS as a function of conversion and temperature. Outside of the fitted temperature range, the model underpredicts the reaction rates at room temperature and 100 °C. Manual mixing of the monomers is determined to be inadequate to obtain a maximum level of cross-linking. Viscosity measurements made at room temperature and elevated temperatures are correlated with the conversion of the prepolymer.
The sensitivity of Drosophila larvae to continuous-wave ultrasound.

Abstract The threshold for killing of freshly hatched Drosophila larvae exposed to continuous-wave (CW) ultrasound shows a minimum at approximately 0.3 MHz. This suggests that the stiffness of the material surrounding the gas bodies in the organism is comparable to water. From this, it is apparent that the gas bodies in three-day-old larvae that we have used in earlier studies are far larger than resonance size at the frequencies (1–5 MHz) used. Yet, these larvae were killed by short exposures to low-temporal-average-intensity pulsed ultrasound with peak intensities of the order of 10 W/cm2. Hence, it appears that “large” bubbles cannot be ignored in considerations of the biological effects of pulsed ultrasound and lithotripsy.
Postoperative Hemodynamic Evaluation of a New Fabric-Covered Ball-Valve Prosthesis

Previous in vitro and in vivo experimental studies have indicated that insertion of the Braun-wald-Cutter fabric-covered ball-valve prosthesis results in negligible thromboembolic complications and hemodynamic performance comparable to that of noncovered mitral and aortic ball-valve prostheses. To assess the clinical efficacy of this fabric-covered valve prosthesis, 35 patients have been followed for 4 to 26 months (540 patient-months) after mitral and/or aortic valve replacement, and 13 have had extensive hemodynamic re-evaluation. In eight patients with the mitral valve prosthesis, the mean diastolic gradient averaged 4.8 mm Hg (range 0 to 8) and the end-diastolic gradient 0.8 mm Hg (range 0 to 2) at a time when the mean heart rate was 75 beats/min (range 50 to 100) and the cardiac output averaged 5.1 L/min (range 3.4 to 8.0). The calculated effective mitral valve orifice size averaged 2.68 cm 2 (range 1.92 to 3.46). In six patients with the aortic valve prosthesis, the average peak systolic gradient was 13 mm Hg (range 0 to 22), and the mean systolic gradient averaged 14.5 mm Hg (range 0 to 24) when the mean heart rate was 82 beats/min (range 64 to 120) and the cardiac output averaged 6.2 L/min (range 3.2 to 9.3). The average effective aortic valve size in the five patients with a mean systolic transvalvular gradient was 1.41 cm 2 (range 1.26 to 1.62). Only one postoperative thromboembolic complication has been observed, and this occurred in a patient with atrial fibrillation and a large left atrium three weeks after discontinuing anticoagulant therapy because of gingival bleeding. These data indicate that use of the fabric-covered Braunwald-Cutter ball prosthesis produces few thromboembolic complications and a satisfactory hemodynamic result.
A note on the estimation of seemingly unrelated regression systems

Abstract In a system of simultaneous equations, one obtains the same results for the overidentified equations by applying three-stage least squares to those equations alone as one would obtain by applying three-stage least squares to the entire system. This paper obtains an analogous result for a system of seemingly unrelated regressions. In doing so it generalizes earlier results of several other authors.
422 IS HUMAN MILK THE BEST FOOD FOR LOW BIRTH WEIGHT BABIES

Carcass analysis data show that the body content of N and minerals throughout fetal life are linearly related to body weight when plotted on double log coordinates. Hence they conform to the allometric (heterogonic) equation Q = bWk, where Q is total body content and b and k are constants. When differentiated this becomes dQ = bkWk-1 dW, which says that N and mineral accretions (dQ) are directly proportional to weight gain (dW) at any given body weight; and since k differs from 1.0 the accretions corresponding to a given weight gain will also vary with body weight. Nomograms (to be presented) based on these equations allow one to read off the retention of N and minerals required to support normal body composition for a given weight and weight gain (maintenance needs are extra). Application of these data to low birth weight babies indicates that human milk fed in usual amounts cannot meet the growth needs for N, Ca, P, Na and Fe in the face of rapid growth. However, it does contain enough K, Cl, Cu, Mg and S. For example, the P content of 10gm of growth tissue in a 1000 gm baby can be calculated from the above formula as follows: dP = 1.45 × 10000.164 × 10(dW) = 45 mg 200 ml human milk (i.e., 200 ml/kg) will provide only 28 mg P, while most commercial formulas will provide about 90 mg P.
Fabrication of Ti-6Al-4V Scaffolds by Direct Metal Deposition

Direct metal deposition (DMD) is a rapid laser-aided deposition method that can be used to manufacture near-net-shape components from their computer aided design (CAD) files. The method can be used to produce fully dense or porous metallic parts. The Ti-6Al-4V alloy is widely used as an implantable material mainly in the application of orthopedic prostheses because of its high strength, low elastic modulus, excellent corrosion resistance, and good biocompatibility. In the present study, Ti-6Al-4V scaffold has been fabricated by DMD technology for patient specific bone tissue engineering. Good geometry control and surface finish have been achieved. The structure and properties of the scaffolds were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and tension test. The microstructures of laser-deposited Ti-6Al-4V scaffolds are fine Widmanstatten in nature. The tensile and yield strengths of the as-deposited Ti-6Al-4V were 1163 ± 22 and 1105 ± 19 MPa, respectively, which are quite higher than the ASTM limits (896 and 827 MPa) for Ti-6Al-4V implants. However, the ductility of the as-deposited sample was very low (∼4 pct), which is well below the ASTM limit (10 pct). After an additional heat treatment (sample annealed at 950 °C followed by furnace cooling), both strength (UTS ∼ 1045 ± 16, and YS ∼ 959 ± 12 MPa) and ductility (∼10.5 ± 1 pct) become higher than ASTM limits for medical implants.
Dynamics of confined methyl iodide studied by Raman spectroscopy

Raman spectroscopy was used to study the vibrational and reorientational dynamics of bulk and confined liquid methyl iodide. A set of five porous silica glasses with pore radii ranging from 15 to 38 A was employed as the confining material. With decreasing pore size a decrease in the ν3 (C– I) vibrational correlation time and an increase in the molecular reorientational correlation time were found. It is noted that the two-state fast-exchange model is not applicable in Raman studies owing to slow diffusion of pore molecules compared with the Raman spectroscopic time-scale. A phenomenological linear correlation between the correlation times and the reciprocal of the pore radius was found to be useful and employed for data analysis. A relatively low sensitivity of the reorientational dynamics of methyl iodide to confinement was explained by considering the shape and mass distribution of a methyl iodide molecule. Copyright © 2000 John Wiley & Sons, Ltd.
Use of pedicle skin grafts in anorectal surgery.

Abstract Occasionally the proctologist finds extensive disease which involves not only a large area of surrounding perianal skin but also the complete circumference and depth of the anal canal. In such a case it is necessary not only to remove all the pathologic condition but also to restore normal function. The creation of a pedicle graft fulfils this requirement. This operation is not recommended as routine, nor is it suggested as a replacement for the useful but simple sliding graft of Carmel. It is suggested, however, that at times it might be useful to an operating surgeon who finds himself with too little too late. It is recommended, therefore, that this surgical procedure be added to the armamentarium of the proctologist.
Chemical kinetic reaction mechanism for the combustion of propane

A detailed chemical kinetic reaction mechanism for the combustion of propane is presented and discussed. The mechanism consists of 27 chemical species and 83 elementary chemical reactions. Ignition and combustion data as determined in shock tube studies were used to evaluate the mechanism. Numerical simulation of the shock tube experiments showed that the kinetic behavior predicted by the mechanism for stoichiometric mixtures is in good agrement with the experimental results over the entire temperature range examined (1150-2600K). Sensitivity and theoretical studies carried out using the mechanism revealed that hydrocarbon reactions which are involved in the formation of the HO2 radical and the H2O2 molecule are very important in the mechanism and that the observed nonlinear behavior of ignition delay time with decreasing temperature can be interpreted in terms of the increased importance of the HO2 and H2O2 reactions at the lower temperatures.
Analysis of slow-wave phenomena in coplanar waveguide on a semiconductor substrate

Slow-wave characteristics of a coplanar waveguide with substrate resistivity are analysed using the mode-matching technique. This waveguide is suitable for microwave monolithic integrated circuits because of its coplanar configuration. Numerical results are presented and compared with an experimental measurement in the literature.
Insulin modulates circulating endothelin-1 levels in humans☆

Recent data indicate that insulin stimulates synthesis of the vasoconstrictor peptide endothelin-1 (ET-1) by cultured vascular endothelial cells in vitro. To determine whether insulin modulates ET levels in vivo and whether this effect is important in the pathogenesis of obesity-associated hypertension, we measured circulating immunoreactive ET-1 levels during euglycemic hyperinsulinemic clamps (20 mU/m2.min-1 for 120 minutes) in eight obese women (body mass index, 36 +/- 1 kg/m2) before and after 10 weeks on an 800-kcal/d protein-sparing liquid diet. During the clamp that preceded weight loss, insulin levels were increased from 17 +/- 2 to 51 +/- 3 mU/L and this was associated with an increment in ET-1 level from 28 +/- 3 to 33 +/- 3 pg/mL (P < .05). After weight loss, insulin levels were increased from 10 +/- 2 to 47 +/- 3 mU/L during the clamp, and there was a corresponding increase in ET-1 levels from 24 +/- 3 to 30 +/- 3 pg/mL (P < .025). The reduction in basal ET-1 level (from 28 +/- 3 to 24 +/- 3 pg/mL) with weight loss correlated strongly with the reduction in fasting immunoreactive insulin level (from 17 +/- 2 to 10 +/- 2 mU/L; r = .92, P < .01). The decrease in blood pressure with weight loss (from 130 +/- 6/73 +/- 3 to 118 +/- 4/72 +/- 3 mm Hg) did not correlate with the corresponding reduction in circulating ET-1 levels. These results indicate that insulin modulates ET-1 levels in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)
The Quanta Image Sensor (QIS): Concepts and Challenges

The Quanta Image Sensor (QIS) concept is presented and its novel properties discussed. Approaches and challenges to counting photoelectrons and Tbit/s readout are discussed. (Invited).
Insulin Degradation in Serum of a Patient with Apparent Insulin Resistance

A case is presented of a thin diabetic male who was resistant to large doses of sc and im insulin but responded to small doses of insulin given iv. His serum contained an enzyme that degraded [l25I]insulin in vitro. We postulate that his apparent insulin resistance was due to inactivation of insulin at the injection site. We propose that the sera of patients with insulin resistance be tested for [125I]insulin-degradingactivity as a possible means of identifying patients with this syndrome.
Juicing the Juice: A Laboratory-Based Case Study for an Instrumental Analytical Chemistry Course

A young, inexperienced Food and Drug Administration (FDA) chemist is asked to distinguish between authentic fresh orange juice and suspected reconstituted orange juice falsely labeled as fresh. In an advanced instrumental analytical chemistry application of this case, inductively coupled plasma (ICP) spectroscopy is used to distinguish between the fresh and reconstituted samples based on their calcium and magnesium concentrations. Students working in teams are given the challenge posed in the case to the FDA chemist. They are charged with designing an experimental procedure, obtaining and analyzing the needed data, and writing a formal report. This case study requires students to conduct themselves in the same manner chemists would in the “real world” when faced with a new and challenging problem. Experimental procedures developed by student teams lead to the correct identification of unknowns a majority of the time. Assessment data indicate this case study elicited positive interest and interactions.
BASELINE ESTIMATED RIGHT ATRIAL PRESSURE BY ECHOCARDIOGRAPHY PREDICTS MORTALITY IN IDIOPATHIC AND ASSOCIATED PULMONARY ARTERIAL HYPERTENSION

Elevated mean right atrial pressure (RAP) measured by cardiac catheterization is an independent risk factor for mortality in the REVEAL (Registry to Evaluate Early and Long-term Pulmonary Arterial Hypertension Disease Management) registry. This study was designed to assess the predictive value of
Causal Diagrams and Multivariate Analysis III: Confound It!

This commentary concludes my series concerning inclusion of variables in multivariate analyses. We take up the issues of confounding and effect modification and summarize the work we have thus far done. Finally, we provide a rough algorithm to help guide us through the maze of possibilities that we have outlined.
Improving Problem-Solving Skills of Family Caregivers Through Group Education

Summary Family caregivers of people with cancer have been asked to assume markedly increased duties and responsibilities as key members of the health care team. To succeed in their new role, they need information that is organized to guide problem-solving and education as well as support in how to apply an orderly problem-solving process the same way that health care professionals do. This article describes an education program designed to teach the principles of problem-solving to caregivers through the use of case studies, and it summarizes the data obtained during a preliminary evaluation of the program.
Radiationless decay in substituted alkylbenzenes in solution

Abstract The singlet state photophysical properties of two sets of substituted alkylbenzenes have been determined in solution. The compounds studied are Ar(CH 2 ) n X where X = H, CH 3 , OH, CN, NH 2 , and CO 2 CH 3 , and n = 1 or 2. For n = 1, both k f and k ic (but not k isc ) show modest trends which may be related to substituent electronegativity; none of these rates are affected in a systematic fashion when n = 2. An amino group increases k ic in both series, presumably through intramolecular exciplex formation. An ester group enhances both ki ic and k isc when n = 1, due to the introduction of n,π ★ character into the first excited singlet state.
Bridging physical and virtual reference with virtual research consultations

Purpose – The purpose of this paper is to discuss merging the virtual learning environment of online students with the traditionally face‐to‐face, physical service of research consultations in the form of virtual research consultations (VRCs).Design/methodology/approach – A literature review discusses the importance of instruction in virtual reference, how to combat inherit challenges and foster an instructional experience during virtual reference interactions, and the value of research consultations. The case study then examines how the Distance Learning Librarian at Norwich University implemented a VRC service.Findings – Based on the ease of maintenance, number of appointments made and verbal feedback from students, VRCs are a valuable addition to virtual reference services for online students. They facilitate instruction in reference, foster relationship building, and also prove a considerable tool for outreach.Practical implications – The case study provides an example of a service that can be impleme...
Online batch/fed-batch process performance monitoring, quality prediction, and variable-contribution analysis for diagnosis

An integrated online multivariate statistical process monitoring (MSPM), quality prediction, and fault diagnosis framework is developed for batch processes. Batch data from I batches, with J process variables measured at K time points generate a three-way array of size I × K × J. Unfolding this three-way array into a two-way matrix of size IK × J by preserving the variable direction is advantageous for developing online MSPM methods because it does not require estimation of future portions of new batches. Two different multiway partial least squares (MPLS) models are developed. The first model (MPLSV) is developed between the data matrix (IK × J) and the local batch time (or an indicator variable) for online MSPM. The second model (MPLSB) is developed between the rearranged data matrix in the batch direction (I × KJ) and the final quality matrix for online prediction of end-of-batch quality. The problem of discontinuity in process variable measurements due to operation switching (or moving to a different ...
Numerical evaluation of exponential integral: Theis well function approximation

This paper reviews various approximation methods for evaluating one form of the exponential integral known as the Theis well function W(u) and presents an algorithm that can be easily implemented to one's desired accuracy for 0 < u < ∞. The algorithm is based on a combination of a fast-converging series representation for small u and an easy-implementing Gauss-Laguerre quadrature formula when u becomes large. The partition point for u varies with the desired program accuracy and efficiency. The error analyses suggested that a partition point in the interval of 1 ≤ u ≤ 4 can yield sufficiently accurate results for practical applications of groundwater problems with minimum computational effort. A comparison of the results revealed that the popular Stehfest inverse Laplace transform technique generally yielded a relative error several orders of magnitude greater than that obtained by the proposed algorithm. For large u, the approximation accuracy increased rapidly using the quadrature formula while the results of the Laplace inversion technique showed numerical oscillation between some positive and negative values.
Behavioral genetic variation, adaptation and maladaptation: an evolutionary perspective

Evolutionary psychology seeks to understand the adaptive, evolved nature of humans by considering the forces of natural selection that gave rise to it. Individual humans also exhibit maladaptation, however, and some of the variation in maladaptive conditions is heritable. An evolutionary perspective can shed light on these phenomena too. Recent work suggests that developmental imprecision importantly affects the fitness of organisms and some of the genetic influences have been identified. Both theory and evidence that developmental imprecision underlies human cognitive maladaptation has begun to accumulate, although the manner in which the developing brain is affected remains largely unknown.
Environmental modeling and exposure assessment of sediment-associated fluoranthene in a small, urbanized, non-riverine estuary☆

Abstract Risks posed by fluoranthene (a four-ring polycyclic aromatic hydrocarbon) in urban runoff were estimated by modeling and exposure assessment of a portion of Murrells Inlet, South Carolina, United States. Kinetic rate constants for sediment-associated fluoranthene and fluoranthene runoff concentrations that were determined in earlier studies were used in these assessments. Computer modeling was used to simultaneously integrate environmental conditions and loading in the estuary with the physico-chemical characteristics of fluoranthene. The Exposure Analysis Modeling System (EXAMS-II) quantitatively characterized relationships between land uses and fluoranthene distribution and fate. Factors predicted to affect oyster exposure were: Non-point source runoff loading > base (background) loading > non-point source hydrologic flows. Simulated pulse loads were predicted to cause only nearby, short-term increases. These results suggest that bioconcentration of fluoranthene by oysters is related to adjacent land uses and can be predicted by understanding the major factors affecting its transport and fate. An approach is described that can be used to test alternate landscape modifications for minimizing impacts on both resident fauna and seafood consumers.
Solidification and Melting of Materials Subject to Convection and Radiation

One-dimensional heat transfer in a finite region of solid or liquid with phase change associated with radiative and convective boundary conditions at the fixed boundary surface is solved using both Blot's variational and Goodman's integral methods. The total solidification time and the rates of solidification obtained based on the present approximate analyses agree very well with the numerical solutions of an earlier work.
Siegfried the Dragonslayer Meets the Web: Using Digital Media for Developing Historical Awareness and Advanced Language and Critical Thinking Skills.

This article describes an undergraduate, German-language course that aimed to improve students' language skills, critical thinking, and declarative knowledge of German history and culture by studying multiple manifestations of the legend of Siegfried the Dragonslayer. The course used web-based e-learning tools to address two major learning challenges. Because learning to think and work with chronological data was required, a web-based timeline building tool, Google Docs Simile, was used to put students in charge of navigating the enormous historical range of the material. The second, related challenge emerged from the geographic, linguistic, and evidentiary diversity of the surviving material, which challenged students to acquire a degree of cultural literacy for an entire region and to apply appropriate interpretive tools to different kinds of evidence. To support this learning outcome, students used blog tool to write a final, collaborative project, in which they designed a simulated alumni tour. The course enhanced students' language skills and built critical historical knowledge essential for understanding German-speaking lands.
An LCAO-MO treatment of the vacancy in diamond

Abstract A simple molecular orbital treatment which has previously been applied successfully to the substitutional nitrogen donor and boron acceptor in diamond is here applied to the vacancy in diamond. Localized levels associated with the vacancy are found in the gap and an outward relaxation of the four neighbors surrounding the vacancy is predicted. Jahn-Teller effects are found to give stabilization energies of ∼0.5 eV. A critical comparison to the ‘defect molecule’ approach of Coulson and Kearsley and Yamaguchi is included.
Assessing the Efficacy of Treatments for the Deficit Syndrome of Schizophrenia

The primary, enduring negative symptoms found in some patients with schizophrenia have become the focus of clinical treatment trials, but there has been no consensus on the best methods for approaching this area. In future trials, a number of issues need to be considered, including analytic strategies, the limitations in instruments used to measure negative symptoms, and study design. An appropriate design for establishing the efficacy of treatments for the deficit syndrome is proposed.
Hospital Surgical Volume and Cost of Inpatient Surgery in the Elderly

Background Strong relationships between hospital volume and quality with inpatient surgery have prompted calls for volume-based referral. However, many are concerned that such policies would steer patients toward higher-cost hospitals. Study Design Using 2005–2007 national Medicare claims, we identified all US hospitals performing elective colectomy for cancer, coronary artery bypass surgery, and abdominal aortic aneurysm repair. Patients were sorted into quintiles based on procedure volumes of the hospital in which they had surgery. For each quintile, we assessed overall 30-day Medicare episode payments adjusted for hospital case mix, including the index hospitalization, readmissions, physician services, and post-discharge ancillary care. Results Hospitals in the lowest-volume quintile had considerably higher case-mix−adjusted episode payments than those in the highest-volume quintile for coronary artery bypass surgery ($960; 2.2% higher) and abdominal aortic aneurysm ($2,796; 8.5% higher), but differences were small for colectomy ($350; 1.3% higher). For coronary artery bypass surgery and abdominal aortic aneurysm repair, the index hospitalization was the largest source of higher overall payments at very low-volume hospitals. For all 3 procedures, very low-volume hospitals had higher payments for both 30-day readmissions and post-discharge ancillary care. Conclusions Volume-based referral policies would not steer patients toward hospitals with high mean costs around episodes of inpatient surgery in the elderly. Minimizing the use of very low-volume hospitals has the potential to reduce costs as well as improve outcomes, particularly for operations with strong volume−outcomes associations.
Abnormal Coronary Flow Velocity Reserve After Coronary Artery Stenting in Patients Role of Relative Coronary Reserve to Assess Potential Mechanisms

Background—Absolute coronary flow velocity reserve (CVR) after stenting may remain abnormal as a result of several different mechanisms. Relative CVR (rCVR=CVRtarget/CVRreference) theoretically normalizes for global microcirculatory disturbances and facilitates interpretation of abnormal CVR. Methods and Results—To characterize potential mechanisms of poststent physiology, CVR was measured using a Doppler-tipped angioplasty guidewire in 55 patients before and after angioplasty, after stenting, and in an angiographically normal reference vessel. For the group, the percent diameter stenosis decreased from 75±13% to 40±18% after angioplasty and to 10±9% (all P<0.05) after stent placement. After angioplasty, CVR increased from 1.63±0.71 to 1.89±0.55 (P<0.05) and after stent placement, to 2.48±0.75 (P<0.05 versus pre- and postangioplasty). After angioplasty, rCVR increased from 0.64±0.26 to 0.75±0.23 and after stent placement to 1.00±0.34. In 17 patients with CVRstent ≤2.0, increased basal coronary flow, rathe...
Rb/Sr-87Sr/86Sr Variations in Bombay Trachytes and Rhyolites (Deccan Traps): Rb-Sr Isochron, or AFC Process?

A petrologically diverse suite of Deccan Trap rocks, comprising basalts, trachytes, rhyolites, and various alkaline rocks, was studied in the Bombay area along the western Indian rifted continental margin. A previous petrogenetic study of these trachytes and rhyolites suggested derivation through fractional crystallization of basaltic magmas, or partial melting of basaltic material at depth, without involvement of continental crust. A Rb-Sr isochron age for the rhyolites was also calculated, but this isochron in our view is fictitious and represents a mixing line instead. Although some of the evolved liquids may have formed by fractional crystallization of basaltic magmas or partial melting of earlyformed basalts, we show that Rb/Sr-87Sr/86Sr variations in the Bombay trachyte-rhyolite suite are consistent with a combined assimilation-fractional crystallization (AFC) process involving a parental trachyte magma (Sr 225 ppm, 87Sr/86Sr = 0.7040) and an Archaean basement gneiss (Sr 145 ppm, 87Sr/86Sr = 0.7690)...
Acceleration of Convergence to the Thermodynamic Equilibrium by Introducing Shuffling Operations to the Metropolis Algorithm of Monte Carlo Simulations

This paper introduces a broad class of operations, called “shuffling trials”, used to design nonphysical pathways. It is shown that in general the equilibrium distribution of a system can be attained when physically possible pathways are interrupted regularly by nonphysical shuffling trials. Including properly chosen shuffling trials in the commonly applied Metropolis algorithm often considerably accelerates the convergence to the equilibrium distribution. Shuffling trials are usually global changes in the system, sampling efficiently every set of the metastable configurations of the system. Shuffling trials are generated by symmetric stochastic matrices. Since ergodicity is not a required property, it is particularly easy to construct these matrices in accordance with the specificity of the system. The design, application, and efficiency of the shuffling trials in Monte Carlo simulations are demonstrated on an Ising model of two-dimensional spin lattices.
A matrix-algebraic solution to two Km servers in a loop

An explicit steady-state solution is given for any queuing loop made up of two general servers, whose distribution functions have rational Laplace transforms. The solution is in matrix geometric form over a vector space that is itself a direct or Kronecker product of the internal state spaces of the two servers. The algebraic properties of relevant entities in this space are given in an appendix. The closed-form solution yields simple recursive relations that in turn lead to an efficient algorithm for calculating various performance measures such as queue length and throughput. A computational-complexity analysis shows that the algorithm requires at least an order of magnitude less computational effort than any previously reported algorithm.
Bone mineralization in children and adolescents with a milk allergy

To evaluate the correlation between dietary calcium intake and mineralization of the immature skeleton 55 children and adolescents aged 5-14 years (mean, 9.5 years) with a positive radioallergosorbent test (RAST) for serum antibodies to cow's milk protein were evaluated. Bone mineral density (BMD) in the lumbar spine and proximal femurs were measured by dual energy X-ray absorptiometry. BMD at each site for each subject was converted to an age-adjusted Z score based on our own series of 95 normal pediatric controls. Calcium intake was determined using a detailed food frequency questionnaire administered by a nutritionist during a 30-40-min interview. Dietary adjustments to the condition varied and resulted in a wide range of calcium intakes. Calcium supplements were taken by 22% of the subjects and were included in the determination of daily calcium intake. The group of 55 subjects was divided into quartiles based on calcium intake (mean +/- S.E mg calcium/day): Group 1, 409 +/- 21, Group 2, 663 +/- 16, Group 3, 950 +/- 32, Group 4, 1437 +/- 124. Bone density Z scores in the proximal femur serially increased across the calcium intake groups (mean +/- S.E.): Group 1, -0.16 +/- 0.31; Group 2, 0.05 +/- 0.33; Group 3, 0.44 +/- 0.24; Group 4, 0.79 +/- 0.41 (P = 0.03). A similar pattern was found with lumbar spine BMD Z scores: Group 1, -0.16 +/- 0.27; Group 2, 0.10 +/- 0.21; Group 3, 0.18 +/- 0.20; Group 4, 0.30 +/- 0.25 (P = 0.05). These data add further to the evidence that dietary calcium intake is important for optimal mineralization of the growing skeleton.
Nontuberculous Mycobacteria in Pleural Fluid: Assessment of Clinical Significance

We reviewed the case records of 22 patients from whose pleural fluid a nontuberculous Mycobacterium (NTM) was isolated. Three patients had pleural effusions definitely due to NTM infection, with evidence of NTM infection in other tissues; 16 had pleural effusions of known etiology unrelated to the isolated NTM and no other evidence of NTM infection; and three had pleural effusions of undetermined etiology and no other evidence of NTM infection. The case histories of the three patients with pleural effusions due to NTM are presented and the significance of the isolation of NTM from the remaining 19 patients is discussed. Criteria are proposed for evaluating the significance of NTM isolated from pleural fluid.
Mesoscale Convective Systems

According to Zipser (1982), a mesoscale convective system (MCS) is a weather feature that exhibits moist convective overturning contiguous with or embedded within a mesoscale circulation that is at least partially driven by the convective processes. Such a broad definition includes a wide variety of mesoscale phenomena ranging from short-lived indiscriminate aggregates of a few thunderstorms to well-organized squall lines to long-lived tropical storms and even hurricanes.
ACTION SPECTRA FOR PHOTOREACTIONS I AND II OF PHOTOSYNTHESIS IN THE BLUE-GREEN ALGA ANACYSTIS NIDULANS

— Action spectra for photoreactions I and II of photosynthesis were obtained for Anacystis nidulans and three of its variants which had altered chlorophyll/phycocyanin ratios. The spectra are properly scaled to each other. They provide information on contributions of phycocyanin and chlorophyll to initial absorption and final distribution of excitation energy to reaction centers I and II. In normally pigmented cells the light harvesting pigments for photoreaction I include about 40% of the phycocyanin and 84% of the chlorophyll. Both in normal cells and in cells with altered pigmentation excitation energy from phycocyanin is delivered to photoreaction II via a small number of chlorophylls. In response to alterations in chlorophyll/phycocyanin ratio Action I spectra showed large variations whereas Action II spectra were essentially invariant. The result is taken to mean that alteration in chlorophyll components in Anacystis is attended by a special restriction: there are only small changes in amount of chlorophyll accessible to photoreaction II in the face of large changes in amount committed to photoreaction I.
After After Many a Summer: A Modern Analysis of Ancient Lifetime Data

To the Editor.— In the fifth chapter of the Book of Genesis, the direct male lineage from Adam to Noah is reported: Adam, Seth, Enosh, Kenan, Mahalalel, Jared, Hanoch, Methuselah, Lamech, and Noah. For nine of these individuals, we are told the age of the individual at which his succeeding son was born, the number of years from this date to the death of the individual, the total number of years that the individual survived, and the fact that the death of the individual was observed. However, for Hanoch no mention is made that his death was observed1: "And Hanoch lived sixty and five years, and begot Methuselah. And Hanoch walked with God after he begot Methuselah three hundred years, and begot sons and daughters. And all the days of Hanoch were three hundred sixty and five years. And Hanoch walked with God,and he was not;for God
Induction immunosuppression with thymoglobulin and rituximab in intestinal and multivisceral transplantation.

Background Induction immunosuppression is now a common practice after intestinal and multivisceral transplantation. We report our experience in 27 adult recipients who received rituximab and rabbit antithymocyte globulin (rATG) in combination as induction agents. Material and methods Twenty-seven adult patients received 29 intestinal transplants between July 2004 and March 2007. All patients received induction immunosuppression therapy with rATG, rituximab, and steroids. Tacrolimums and a steroid taper were used for maintenance therapy. Patient and graft survival, episodes of rejection as well as posttransplant lymphoproliferative disease (PTLD) and graft-versus-host disease were analyzed. Results One-year patient and graft survival was 81% and 76%, respectively. Thirteen patients (48%) experienced 19 episodes of acute rejection (9 mild episodes, 2 moderate, and 8 severe). Patients with a multivisceral graft experienced less episodes of severe acute rejection (1 of 19, 5%) when compared with isolated intestinal transplants and modified multivisceral transplants (7 of 10, 70%). Two patients had episodes of skin graft-versus-host disease that responded to steroid boluses. PTLD was not seen in our series. Two patients developed cytomegalovirus enteritis. Conclusions The combination of rATG and rituximab was an effective induction therapy in our preliminary data. The number and severity of rejection episodes increased when the liver was not included as part of the graft. An immunosuppression regimen including rATG, rituximab, and steroids may have a protective effect against PTLD and chronic rejection.
Hybrid Simulations of the Effects of Energetic Particles on Low-Frequency MHD Waves

A hybrid MHD-gyrokinetic simulation model is presented which is suitable for self-consistent study of the interaction of energetic particles with low-frequency MHD waves. Fully electromagnetic gyrokinetic equations are used to describe the energetic particles, while the cold background plasma is treated as a fluid, using nonlinear one-fluid MHD equations. Based on this model a hybrid MHD-gyrokinetic particle code has been developed. A ?falgorithm has been implemented in the code for s ~ 1 electromagnetic perturbations. The gyrokinetic description enables us to remove the restriction on the particle time step dictated by the gyromotion, while the ?falgorithm strongly reduces the simulation numerical noise level. Therefore, considerably larger time steps and a smaller number of particles can be used in the simulations as compared to conventional methods. The conservation properties of the model and corresponding ?fscheme have been investigated. Representative two-dimensional simulations of the mirror instability and the temperature gradient driven instability of the compressional mode were performed, and the simulation results are in very good agreement with linear theory.
Conceptualizing the Economic Role of the State: Laissez-Faire, Technocracy, and the Democratic Alternative

This article contrasts three visions of political economy that appear in the writings of Keynes, Hayek, and Polanyi, and discusses their relevance to current debates over economic policy in the United States. Keynes proposed optimizing market practices through technocratic governance. In recent decades, this influential approach has proven vulnerable to the revival of Hayek's laissez-faire arguments. Polanyi, by contrast, introduced a framework that criticizes both laissez-faire conceptions and the technocratic approach pioneered by Keynes. Because of its emphasis on democratic participation, Polanyi's reasoning provides the building blocks for a new type of contemporary progressive politics.
Substrate topography shapes cell function

Influencing cell behavior from proliferation to differentiation using substrate or implant topography is an attractive strategy for regenerative medicine applications. Substrate topography at the submicron range is of particular interest because the size range is comparable to extracellular matrix structures. Emerging literature presents many interesting findings on how nanotopography enhances cell adhesion, alters cell morphology, affects proliferation, initiates intracellular signaling, provides contact guidance and mediates stem cell differentiation. Incorporating topographical consideration into the design of a biomimetic microenvironment for cell culture will become increasingly important in light of these studies and practical with advances in nanofabrication technologies. This Highlight underscores the promise of and the unknown information about topographical effects in manipulating cell-substrate interaction and advancing tissue engineering.
Simultaneous quantitative flow measurement using PIV on both sides of the air–water interface for breaking waves

An experimental method for simultaneously measuring the velocity fields on the air and water side of unsteady breaking waves is presented. The method includes a novel technique for seeding the air flow such that the air velocity can be resolved in the absence of wind. Low density particles that have large Stokes drag and ability to respond to high-frequency flow fluctuations are used to seed the air flow. Multi-camera, multi-laser particle image velocimetry setups are applied to small-scale unsteady breaking waves, yielding fully time-resolved velocity fields. The surface tension of the fluid is altered and controlled to form spilling breaking waves. Results for the velocity and vorticity fields of representative spilling breakers, which show shedding of an air-side vortex and well-documented generation of water-side vorticity, are presented and discussed.
The Pediatric Subspecialty Workforce: Time to Test Our Assumptions

Over 20 years ago, my experiences as a rural National Health Service Corps physician challenged my assumptions that nearby pediatric care was of primary importance to parents. About halfway through my first year of practice, I was surprised to realize that many families continued to drive as long as 90 minutes to be seen by a family practitioner or an exceedingly busy pediatrician—this despite my Johns Hopkins training and wide-open practice. At the time, I ignored the contradiction that my family and I would routinely bypass our small town's grocery store and travel the extra hour to a slightly larger emporium that sold Pepperidge Farm cookies and Thomas' English Muffins, which were considered luxury foods in the northern tip of New Hampshire. Geography may be important in rural areas, but it is not destiny. In this issue of Pediatrics , Mayer1 provides a vivid and detailed description of the geographic availability of pediatric subspecialists. The limited supply of these physicians can vex families, primary care physicians, children's hospitals, and medical schools. This is a long-standing problem,2 with a recent heightened level of concern.3 Despite efforts over 4 decades to address the overall shortage and geographic disparities, the goal of reducing supply barriers to children's subspecialty care remains a mirage on the horizon; we keep on walking but never seem to get closer. Perhaps this is because of the assumptions that we hold close to our professional hearts. For example, my experience as a rural pediatrician revealed that the “cost” and perception of travel and quality vary by parents. Assuming that closer medical care is always better can bind us to policy goals that are difficult, perhaps impossible, to achieve. What other assumptions do we make about the pediatric subspecialty workforce? I will review some of the assumptions … Address correspondence to David C. Goodman, MD, MS, Dartmouth Medical School, Department of Pediatrics, Center for Evaluative Clinical Sciences, 7251 Strasenburgh Hall, Hanover, NH 03755. E-mail: david.goodman{at}dartmouth.edu
A Sequential procedure for studies comparing multiple doses

An attractive method of dealing with the multiplicity inherent in studies comparing multiple doses is to use a testing strategy in which hypotheses (or sets of hypotheses) are tested in a prespecified order, with rejection at each step a necessary condition for continuation to the next step. Such a strategy naturally lends itself to interim monitoring. We demonstrate how this may be achieved. Copyright © 2002 John Wiley & Sons, Ltd.
Future execution: a hardware prefetching technique for chip multiprocessors

This paper proposes a new hardware technique for using one core of a CMP to prefetch data for a thread running on another core. Our approach simply executes a copy of all non-control instructions in the prefetching core after they have executed in the primary core. On the way to the second core, each instruction's output is replaced by a prediction of the likely output that the nth future instance of this instruction will produce. Speculatively executing the resulting instruction stream on the second core issues load requests that the main program will probably a reference in the future. Unlike previously proposed thread-based prefetching approaches, our technique does not need any thread spawning points, features an adjustable lookahead distance, does not require complicated analyzers to extract prefetching threads, is recovery-free, and necessitates no storage for the prefetching threads. We demonstrate that for the SPECcpu2000 benchmark suite, our mechanism significantly increases the prefetching coverage and improves the primary core's performance by 10% on average over a baseline that already includes an aggressive hardware stream prefetcher. We further show that our approach works well in combination with runahead execution.
Compositions of Mercury's earliest crust from magma ocean models

article i nfo Article history: The size of the Mercurian core and the low ferrous iron bearing silicate content of its crust offer constraints on formation models for the planet. Here we consider a bulk composition that allows endogenous formation of the planet's large core, and by processing the mantle through a magma ocean, would produce a low-iron oxide crust consistent with observations. More Earth-like bulk compositions require silicate removal, perhaps by a giant impact, to create the planet's large core fraction. We find that the endogenous model can produce a large core with either a plagioclase flotation crust or a low-iron oxide magmatic crust. Because a magma ocean creates a gradient in iron oxide content in the resulting planetary mantle, the parts of the mantle removed by a putative giant impact could result in either a high-iron oxide mantle in contradiction to current crustal measurements, or a low-iron oxide mantle consistent with the current understanding of Mercury. If a giant impact cannot preferentially remove shallow mantle material then the proto-Mercury must have had a bulk low iron-oxide composition. Thus a specific bulk composition is required to make Mercury endogenously, and either a specific process or a specific composition is required to make it exogenously through giant impact. Measurements taken by the MESSENGER mission, when compared to predictions given here, may help resolve Mercury's formation process.
Control system design by multiobjective optimization

We consider posing control system design as a multiobjective optimization problem and survey some of the tools for solving this problem.