cssi/SciSciGPT-SciSciNet huggingface dataset:
Survival and outcomes following bioprosthetic vs mechanical mitral valve replacement in patients aged 50 to 69 years.

Importance In nonelderly patients with mitral disease requiring valve replacement, deciding between bioprosthetic and mechanical prosthetic valves is challenging because long-term survival and morbidity are not well defined. Objective To quantify survival and major morbidity after mitral valve replacement in patients aged 50 to 69 years. Design, Setting, and Participants Retrospective cohort analysis of 3433 patients (aged 50-69 years) who underwent primary, isolated mitral valve replacement in New York State hospitals from 1997-2007. Follow-up ended November 30, 2013; median duration was 8.2 years (range, 0-16.8 years). Propensity score matching for 19 baseline characteristics yielded 664 patient pairs. Exposures Bioprosthetic vs mechanical prosthetic mitral valve replacement. Main Outcomes and Measures All-cause mortality, stroke, reoperation, and major bleeding events. Results No survival difference was observed between use of mechanical prosthetic and bioprosthetic mitral valves in patients aged 50 to 69 years matched by propensity score (209 and 221 deaths, respectively), or in a subgroup analysis of age by decade. Actuarial 15-year survival was 57.5% (95% CI, 50.5%-64.4%) after mechanical replacement vs 59.9% (95% CI, 54.8%-65.0%) after bioprosthetic valve replacement (hazard ratio [HR], 0.95 [95% CI, 0.79-1.15], P = .62). The 15-year cumulative incidence of stroke was higher after mechanical (65 strokes; 14.0% [95% CI, 9.5%-18.6%]) vs bioprosthetic valve replacement (41 strokes; 6.8% [95% CI, 4.5%-8.8%]) (HR, 1.62; 95% CI, 1.10-2.39). The 15-year cumulative incidence of reoperation was lower for mechanical (28 reoperations; 5.0% [95% CI, 3.1%-6.9%]) compared with bioprosthetic (47 reoperations; 11.1% [95% CI, 7.6%-14.6%]) valves (HR, 0.59; 95% CI, 0.37-0.94). The 15-year cumulative incidence of a bleeding event was higher for mechanical (72 events; 14.9% [95% CI, 11.0%-18.7%) vs bioprosthetic (49 events; 9.0% [95% CI, 6.4%-11.5%]) valves (HR, 1.50; 95% CI, 1.05-2.16). Conclusions and Relevance Among patients aged 50 to 69 years undergoing mitral valve replacement in New York State, there was no significant survival difference at 15 years in patients matched by propensity score who underwent mechanical prosthetic vs bioprosthetic mitral valve replacement. Mechanical prosthetic valves were associated with lower risk of reoperation but greater risk of bleeding and stroke. Even though these findings suggest bioprosthetic mitral valve replacement may be a reasonable alternative to mechanical prosthetic valve replacement in patients aged 50 to 69 years, the 15-year follow-up was insufficient to fully assess lifetime risks, particularly of reoperation.
Special Issue Editorial Introduction: Grids and Geospatial Information Systems

Grids and Geospatial Information Systems (GIS) are both based on distributed service architectures and have complementary capabilities. GIS systems provide a comprehensive set of services for managing maps, geospatial data sets, and geospatial information that can be applied to areas ranging from access to scientific data by researchers to disaster planning and emergency management. The data and information focus of GIS are being augmented with the computational and virtual organization capabilities of Grid computing by many projects, including the ones by the contributors to this special issue. This editorial introduction serves as an overview of the issues discussed at the GIS-Grid Workshop in the Open Grid Forum and the follow-on papers of this special issue. Copyright © 2008 John Wiley & Sons, Ltd.
Equilibrium theory of surface deposition from particle-laden dilute, saturated vapor containing laminar boundary layers

Abstract Mass deposition rates on cooled solid surfaces exposed to saturated mainstreams containing a dispersed condensate aerosol are influenced by both the thermophoretic capture of such particles and the inevitable scavenging of vapor that takes place during their transit through the thermal boundary layer (BL). A tractable asymptotic theory is presented which allows total mass deposition rates to be predicted from such coupled two-phase boundary layers on the realizable assumptions that the dispersed condensate: (i) is captured predominantly as a result of thermophoresis down the prevailing temperature gradient, and (ii) is able to maintain the condition of local vapor—condensate phase equilibrium (LVCE) throughout the thermal BL. It is shown that under such circumstances the total mass deposition rate can be conveniently split into three additive contributions, the simplest being the vapor contribution, which can be computed (based on LVCE) without a knowledge of the condensate contributions. The latter can themselves be split into two calculable portions—one associated with the deposition rate of the mainstream particles computed in the (hypothetical) absence of vapor scavenging, and one associated with the amount of condensate scavenged from the vapor during the process of particle thermophoresis across the thermal BL. The present formulation applies to carrier gas—vapor—condensate systems of any Prandtl number (Pr), vapor Schmidt number, dilute condensate mass fraction, dimensionless condensate particle thermophoretic diffusivity, and heat of vaporization. Illustrative numerical results are presented here for high Reynolds number, Pr = 0.7 (air-like) streams in forward stagnation-point flow (two-dimensional and axisymmetric) or flat-plate flow, for absolute surface temperatures in the range 0.5 ⩽ Tw/T∞ ⩽ 1.0, over the interesting ranges of dimensionless thermophoretic diffusivities (αTDc/v) and latent heats [Λ/(RT∞)].
Structural properties of the oxide superconductors: the critical role of defects

Structural data have contributed greatly to the understanding of the oxide superconductors. However, it is increasingly clear that a knowledge of the average structure is not sufficient. Structural defects, which are present in essentially all of these systems, have a profound effect on the superconducting properties.
Intermolecular protein interactions in solutions of calf lens alpha-crystallin. Results from 1/T1 nuclear magnetic relaxation dispersion profiles.

From analyses of the magnetic field dependence of 1/T1 (NMRD profiles) of water protons in solutions of calf lens alpha-crystallin at several concentrations, we find two regimes of solute behavior in both cortical and nuclear preparations. Below approximately 15% vol/vol protein concentration, the solute molecules appear as compact globular proteins of approximately 1,350 (cortical) and approximately 1,700 (nuclear) kD. At higher concentrations, the effective solute particle size increases, reversibly, as evidenced by the appearance of spectra-like 14N peaks in the NMRD profiles and a change in the field and temperature dependence of 1/T1. At these higher concentrations, the profiles are very similar to those of calf gamma II-crystallin, a crystallin that undergoes an analogous transition near approximately 15% protein (Koenig, S. H., C.F. Beaulieu, R. D. Brown III, and M. Spiller, 1990. Biophys. J. 57:461–469). By comparison with recent analyses of NMRD results for solutions of immobilized proteins as models for the transition from protein solutions to tissue (Koenig, S. H., and R. D. Brown III. 1991. Prog. NMR Spectr. 22:487–567), we argue that alpha-crystallin solute behaves as aggregates approximately greater than 50,000 kD as protein concentration is progressively increased above 15%. Finally, the concentration dependence of the NMRD profiles of alpha- and gamma II-crystallin can readily explain recent osmotic pressure data, in particular the intersection of the respective pressure curves at approximately 23% vol/vol (Veretout, F., and A. Tardieu. 1989. Eur. Biophys. J. 17:61–68).
Social perception of the personality of the disabled

This paper examines the perception of disability in relation to the disability status of a hypothetical person and that of the experimenter. Meyer, Gouvier, Duke, and Advokat (2001) found that participants had positive attitudes towards disability if the experimenter was disabled. This experiment moves the study of perceptions about disability into the realm of personality. Participants ( N = 120) read a scenario in which the target person was either disabled or nondisabled while sessions were conducted by either a disabled or a nondisabled experimenter. They rated the target on the Big Five Personality Scale that involves a self-rating and an others-rating. The participants believed that others view disabled people less positively than they themselves do.
A METHOD FOR CUTTING GLASS TUBING.

do not extend south of North Carolina and do not represent true desert conditions. The more southerly of these areas indicate distinctly less arid climates than those farther north, and even contain appreciable quantities of coal, which Brooks interprets as a product of equatorial rain forests. It is perhaps too much to expect a meteorologist to be fully qualified to deal with purely geological questions, but when he ventures into a field in which geology plays almost as important a part as meteorology, the active collaboration of a geologist of recognized standing would appear to be a highly desirable safeguard. It would at least prevent such violence to terminology as the indiscriminate use of the word "period" to describe any and all intervals of geologic time, from "Mesozoic period" to "Pliocene period." Although marred by too frequent errors such as those mentioned, the book is nevertheless a remarkable and highly valuable work. A prodigious amount of labor has gone into its preparation. It is to be hoped that it will have a salutary effect on those who see in new and fantastic hypotheses the only solution to the problem of geologic climates. MALCOLm H. BiSSELL CLARK UNIVERSITY
Immunological Studies on Fertility and Sterility. III. Effect of Isoimmunization with Blood and Semen on Fertility in Cattle

Summary An attempt was made to determine the importance of antigen-antibody reactions as potential causes of lowered fertility in cattle. Seventeen heifers exhibited anaphylactic-like reactions after repeated intravenous injections of bull semen. Antibodies against bull sperm were not detectable by laboratory tests made on their sera. When the heifers were bred to the bull whose semen they had received, eight conceived on first service and three of the remaining nine on the second. Results from first service were not different from those obtained with the same bulls on nonimmunized cows. The conception rate on second service was low, but not significantly so. The hypothesis was then tested that local antibody production is a factor in lowered fertility. Twelve heifers received repeated intrauterine injections of a bull's blood. Antibodies were not demonstrable in the reproductive organs throughout the treatment period, but were produced in the sera of six of the heifers—probably in response to antigens which passed into the circulation. When the twelve heifers were bred to the bull used as the blood donor, eight conceived on first service and two on the second. There was no indication that this treatment had reduced fertility. The results would be considered more critical if it had been possible to demonstrate antibodies in the lumen of the reproductive organs of the heifers.
Use of inhibitory (anti-catalytic) antibodies to study extracellular proteolysis.

The specific role of proteolytic enzymes in the degradation by live cells of fibrillar model matrices (fibrin, collagen) was studied using monoclonal and polyclonal inhibitory (anti-catalytic) antibodies. Dissolution of fibrin by plasminogen-supplemented human HT-1080 cells was blocked by (1) omission of plasminogen, (2) inhibitory anti-plasmin antibody, and (3) inhibitory anti-u-PA antibody but not by non-inhibitory control antibodies. Using a similar approach, it was shown that the dissolution of reconstituted type I collagen fibrils by trypsin-supplemented live human skin fibroblasts was blocked by inhibitory antibodies to fibroblast-type procollagenase but not by non-inhibitory control antibodies. These findings permit us to deduce that, at least in culture, the dissolution of fibrin by plasminogen-supplemented HT-1080 cells was mediated by plasminogen-assisted proteolysis which entailed the extracellular conversion of plasminogen to plasmin by cell-derived u-PA, and that the dissolution of collagen f...
Inflammation, Metalloproteinases, and Increased Proteolysis An Emerging Pathophysiological Paradigm in Aortic Aneurysm

Abdominal aortic aneurysm is a common and potentially lethal disease with an estimated incidence of 20 to 40 cases per 100 000 persons per year.1 In the United States, nearly 45 000 operations are performed annually for AAA.2 Most aneurysms are clinically silent until the time of rupture. Elective surgical mortality for unruptured aneurysms varies from 2% to 7%, but mortality jumps to 50% to 70% when rupture occurs before surgery.2 Risk factors for the development of AAA include advancing age, male sex, chronic obstructive lung disease, cigarette smoking, hypertension, and genetic factors.2 One of the most important determinants of risk for rupture is the size of the aneurysm.2 The overall risk of rupture is 3% to 8% for aneurysms 5 cm.2 Aneurysms between 4 and 4.5 cm in diameter carry a 10% to 12% risk of rupture.2 Although there is a considerable variability in the rate of expansion, on average, expansion occurs in an exponential fashion with an ≈10% diameter increase per year (0.3 to 0.6 cm/y for aneurysms 3 to 6 cm in size).2 Expansion rate is reduced by β-blockers and enhanced in patients with uncontrolled diastolic hypertension, smoking, and chronic obstructive lung disease.3 Recent clinical and experimental studies have challenged the long-held notion that AAA results primarily from a complication of atherosclerosis.4 Although intimal pathological lesions characterize occlusive atherosclerotic aortic disease, one of the striking hallmarks of AAA is the extensive degeneration of the media, with evidence for extensive loss of elastin in the media and adventitia, apoptosis and decrease in the number of matrix-synthesizing medial smooth muscle cells, and an adventitial and transmural inflammatory infiltrate consisting of macrophages, lymphocytes, …
Impact of Arabian Sea pollution on the Bay of Bengal winter monsoon rains

[1] Accumulation of pollution over the southern Arabian Sea has been documented in numerous studies that followed the INDOEX field project of 1992. In this paper, we show several examples of this feature from the MODIS/CALIPSO data sets. We identify this feature as the Bombay Plume that makes its way into the Arabian Sea from the west coast of India. A second part of this work is on modeling the impacts of pollution. We use a NASA Goddard Earth Observing System (GEOS) model to carry out many comparative forecast simulation experiments that include the pollution based on MODIS and control runs that utilize climatological estimates of pollutions. The model invokes both the direct and indirect effects of aerosols. Our observations are as follows: (1) The Arabian Sea experienced above normal rain during these periods for the MODIS experiments as compared to the control. (2) The most interesting feature is the divergent outflow center, in the upper troposphere, over polluted regions of the atmosphere over the Arabian Sea as a consequence of tropospheric aerosol heating. (3) An important related feature is a compensating downward lobe with a divergent inflow in the upper troposphere center over the Bay of Bengal. (4) The presence of this downward lobe over the Bay of Bengal relates to a reduction of winter monsoon rains over the southeast coast of India. (5) We also show evidence of similarly reduced winter monsoon rains in raingauge data over the southeast coast of India during high-pollution events ascertained from MODIS data.
The nature of L8 and L8S8 forms of ribulose bisphosphate carboxylase/oxygenase from Chromatium vinosum.

Abstract L8 and L8S8 forms of ribulose bisphosphate carboxylase/oxygenase (RubisCO) have been prepared from Chromatium vinosum by the extremely mild method of centrifugal fractionation. Only the L8S8 form is detectable in crude extracts of this organism. Both forms show immunological identity in double diffusion studies using antibody to L subunits of the L8S8 form. L subunits from both L8 and L8S8 enzymes are identical by the criteria of peptides observed after limited proteolysis and N-terminal sequence analysis. In addition, these subunits show regions of homology with L subunits from Rhodospirillum rubrum, Anacystis nidulans, and spinach. S subunits of the C. vinosum enzyme are completely homologous to those from A. nidulans and higher plants from the 18th through 25th residue, a stretch preceded in all cases by two basic amino acids.
Ephrin signaling establishes asymmetric cell fates in an endomesoderm lineage of the Ciona embryo

Mesodermal tissues arise from diverse cell lineages and molecular strategies in the Ciona embryo. For example, the notochord and mesenchyme are induced by FGF/MAPK signaling, whereas the tail muscles are specified autonomously by the localized determinant, Macho-1. A unique mesoderm lineage, the trunk lateral cells, develop from a single pair of endomesoderm cells, the A6.3 blastomeres, which form part of the anterior endoderm, hematopoietic mesoderm and muscle derivatives. MAPK signaling is active in the endoderm descendants of A6.3, but is absent from the mesoderm lineage. Inhibition of MAPK signaling results in expanded expression of mesoderm marker genes and loss of endoderm markers, whereas ectopic MAPK activation produces the opposite phenotype: the transformation of mesoderm into endoderm. Evidence is presented that a specific Ephrin signaling molecule, Ci-ephrin-Ad , is required to establish asymmetric MAPK signaling in the endomesoderm. Reducing Ci-ephrin-Ad activity via morpholino injection results in ectopic MAPK signaling and conversion of the mesoderm lineage into endoderm. Conversely, misexpression of Ci-ephrin-Ad in the endoderm induces ectopic activation of mesodermal marker genes. These results extend recent observations regarding the role of Ephrin signaling in the establishment of asymmetric cell fates in the Ciona notochord and neural tube.
Naloxone does not impair conditioned inhibition of the rabbit’s nictitating membrane response

The possibility that the endogenous opiates are involved in conditioned inhibition of the nictitating membrane response was investigated by administering the opiate antagonist naloxone to albino rabbits. It was hypothesized that naloxone administration would increase responding to the inhibitory conditioned stimulus. However, no such increase was observed. These findings suggest that an alternate mechanism, possibly the brain-stem reward system, may be involved in conditioned inhibition.
Glutamate Transport and Production in Brevibacterium flavum

l-Glutamate was taken up and concentrated into washed cells of Brevibacterium flavum, a glutamate-producing bacterium. Potassium ions specifically promoted the uptake rate. The uptake activity in the presence of K+ was inhibited by carbonyl cyanide-m-chlorophenyl hydrazone but not by N,N′-dicyclohexylcarbodiimide, NaN3, ouabain, valinomycin or gramicidin. The activity was specifically and competitively inhibited by l-aspartate among l-amino acids but not so strongly by other structural analogues including d-glutamate. l-Aspartate uptake was also competitively inhibited by l-glutamate. Michaelis constants for glutamate and aspartate were 19 and 25 μM, respectively. The glutamate uptake activity of the cells increased when NH4+ in the culture medium was reduced. Five out of six mutants which were unable to grow on glutamate and produced more glutamate than the parent showed a lower maximum rate of uptake than the parent.
ViewpointProgram committee overload in systems

Conference program committees must adapt their review and selection process dynamics in response to evolving research cultural changes and challenges.
Shear stress-conditioned, endothelial cell-seeded vascular grafts: improved cell adherence in response to in vitro shear stress.

Background . Prosthetic vascular grafts with adherent endothelial cell monolayers may prove useful for small-caliber vessel bypass. However, endothelial cells adhere poorly to prosthetic graft material, and they are stripped when exposed to in vivo shear stress. This study sought to determine whether in vitro shear stress conditioning improves endothelial cell adhesion and decreases thrombogenicity of endothelial cell-seeded grafts. Methods . The lumens of 1.5 mm (inside diameter) spun polyurethane polymer vascular grafts were seeded with bovine aortic endothelial cells and cultured in vitro for 6 days with or without continuous laminar shear stress, first at 1 to 2 dynes/cm 2 for 3 days, then at approximately 25 dynes/cm 2 for 3 days. Grafts preconditioned by shear stress and the static control grafts were then exposed to arterial shear stress at 25 dynes/cm 2 for 25 seconds. The number of dislodged cells was counted, and the grafts were examined by light and scanning electron microscopy. Whole blood clotting time in the grafts was also determined. Results . Exposure of grafts to acute shear stress dislodged 1.35×10 6 ±0.44×10 6 cells from static grafts compared with 1.05×10 4 ±0.16×10 4 cells from grafts preconditioned by shear stress. By light and electron microscopy an intact endothelial monolayer was observed to cover the lumen of shear stress-conditioned grafts, whereas few cells remained on the luminal surface of grafts not previously exposed to shear stress. The clotting time in shear stress-conditioned grafts was significantly prolonged in relation to grafts not exposed to shear stress. Conclusions . These findings show that endothelial cell adhesion and retention on vascular grafts in vitro is markedly enhanced by preconditioning the seeded endothelial cell monolayer with long-term shear stress. Consequently, vascular grafts containing shear stress-conditioned endothelial monolayers are less thrombogenic in vitro than small-caliber vascular grafts without intact endothelial cell monolayers.
Combined heart and lung transplantation for unresectable primary cardiac sarcoma

Abstract Objective: The prognosis for patients with primary cardiac sarcoma is poor. Median survival is less than 10 months, especially when complete surgical excision is not feasible. Removal of all cardiopulmonary structures involved by tumor followed by orthotopic allotransplantation has been proposed to improve long-term survival. Methods: From 1996 through 1999, we performed combined heart and lung resection followed by en bloc heart and bilateral lung transplantation in 4 patients (2 men and 2 women): 2 with inoperable pulmonary arterial sarcoma and 2 with left atrial sarcoma extending into the pulmonary vein. Results: Median age at diagnosis was 39 years (range 37-45 years). All 4 patients were given chemotherapy before transplantation: doxorubicin and ifosfamide in 2 cases, and doxorubicin, ifosfamide, mesna, and dacarbazine in 2 cases. There were no operative deaths. Median survival after transplantation was 31 months (range 5-49 months). All patients had tumor recurrence: local recurrence in the chest (n = 1) and distant metastases in the brain (n = 2) and abdomen (n = 1). One patient remains alive 49 months after disease progression with cerebral metastasis as the only site of recurrence treated with whole-brain irradiation, resection, and stereotactic radiosurgery. Conclusions: Combined heart and lung transplantation is a technically feasible treatment for highly selected patients with localized advanced primary cardiac sarcomas. The high incidence of metastatic disease, however, limits its utility. J Thorac Cardiovasc Surg 2002;124:1145-8
Psychogenic polydipsia and water intoxication—Concepts that have failed

Ten patients (8 men, 2 women; mean age 38.7 +/- 8.1 years), 7 of whom had schizophrenic disorders and 3 of whom had bipolar disorder (manic-depressive illness), manifested psychosis, intermittent hyponatremia, and polydipsia (PIP syndrome). The relationship between serum sodium and urinary water excretion among the 10 PIP patients is described in detail. The success of lithium in improving serum sodium levels and in decreasing urinary water excretion among the three PIP patients with bipolar disorder and the failure of changes in urinary water excretion to explain changes in serum sodium levels among the 10 PIP patients argue against "psychogenesis" as the explanation for the polydipsia and excessive water intake as the sole explanation for hyponatremia or complications ascribed to water intoxication.
Economic impact of kidney stones in white male adults

A large survey of patients hospitalized for kidney stones in the Carolinas and the Rocky Mountain states yielded information that can be translated into conservative estimates of cost of this disease. Hospital costs were estimated by considering number of surgeries, the approximate cost of various types of surgery, number of days hospitalized, and room rates. Work force costs were estimated from information on work days lost and income categories. Estimated recurrence rates for this disease are used to approximate the total cost, due to stones, for the next year for a current stone case. Each incident of stone disease costs, on the average, approximately $2,000, exclusive of recurrences. Hospital stays average four to five days. The average annual cost of recurrence for a current stone case is conservatively estimated to be in the $300 to $400 range. A conservative projection of these costs to the entire national population of white males in the age range of eighteen to sixty years yields an annual cost due to kidney stones approaching $315,000,000.
Fingerprint reference verification method using a phase-encoding-based watermarking technique

We propose a phase-encoding-based digital watermark- ing technique for fingerprint template protection and verification. We extract a signature from the one-dimensional Fourier phase of the original fingerprint image (template) and then embed it back into the image using a variation of phase-shift keying modulation and the spread-spectrum method. To minimize the degradation to important minutiae features of fingerprint data, we segment the template into a region of interest (ROI) and a region of background (ROB) and em- bed the watermark adaptively in these two regions using an adap- tive phase quantization method. We give experimental results with fingerprint biometric data that demonstrate the protection of finger- print templates as well as the verification of fingerprint recognition. © 2008 SPIE and IS&T. DOI: 10.1117/1.2891312
Nuclear sample management using a plutonium dissolution robotic system

At Los Alamos National Laboratory, a unique sample management robotic system has been developed that automates plutonium metal acid dissolutions, the aliquoting of resulting solutions to be analyzed using several analytical chemistry methods, and automates the barcode labeling of the solution containment vial providing positive solution identification. This system is based upon a commercial laboratory robot from Zymark, Inc. that has been enhanced by the addition of custom robotic workstations engineered and fabricated at our facility. This system will significantly reduce personnel radiation exposure and eliminate the redundancy of each analytical area producing separate dissolved plutonium solutions, which are used in chemical analyses.
Performance analysis using Petri nets

The purpose of this paper is to focus on the implementation issues associated with using Petri nets for the performance analysis of discrete event dynamic systems while demonstrating several applications in manufacturing systems. Practical modeling issues will be discussed and several applications will be presented that illustrate the advantages and limitations of this methodology. These issues lead to the definition of several research problems in Petri nets for performance analysis.
Determination of Sex from the Tibia

Determination of sex from the tibial shaft as well as the entire bone itself has not been generally investigated by osteologists . This paper is an attempt to fulfill this need. The purpose is to determine sex from both the complete tibia and the shaft at the nutrient foramen level. The sample was obtained from the Terry Collection and included 159 specimens of whites and blacks. The tibial length, and circumference, anteroposterior, and transverse measurements at the nutrient foramen level were analyzed by means of step-wise discriminant function analysis. It was found that the circumference alone could give, on the average, 80% accuracy in determining sex. The addition of other dimensions to the function increased the accuracy by about 4%. Comparisons of this study with those on the femur indicated that sexual dimorphism in the tibia was a result not only of the general growth and musculo-skeletal activity, but also of the genetic structure of the population, i.e., racial variation.
Visualization and Characterization of Small-Scale Spanwise Vortices in Turbulent Channel Flow

High-resolution particle-image velocimetry (PIV) measurements are made in the streamwise - wall-normal plane of turbulent channel flow at Re$_{τ}$=566, 1184 and 1759, facilitating documentation of the population trends and core diameters of small-scale spanwise vortices. Swirling strength, an unambiguous vortex-identification criterion and hence a local marker of rotation, is used to extract small-scale spanwise vortex cores from the instantaneous velocity fields. Once the small-scale vortices are properly extracted from the PIV realizations, their characteristics are studied in detail. The present results indicate that the very-near-wall region (y < 0.1 h) is densely populated by spanwise vortices with clockwise (negative) rotation. This behavior supports the notion that hairpin-like vortices are generated very close to the wall and grow into the outer layer as they advect downstream. In contrast, counterclockwise (positive) spanwise vortices are scarce in the very-near-wall region, but their presence steadily increases within the logarithmic layer presumably due to a localized generation mechanism. The average core diameter of negative spanwise vortices is found to be larger than the average diameter of positive vortices, with few positive vortices having core diameters exceeding 80 y$_*$.
Distinction between degenerative and isthmic spondylolisthesis on sagittal MR images: importance of increased anteroposterior diameter of the spinal canal ("wide canal sign").

The purpose of this study was to determine whether a visually apparent increase in the anteroposterior diameter of the spinal canal ("wide canal sign") can be used reliably to differentiate degenerative from isthmic spondylolisthesis on midline sagittal MR images. We hypothesized that the wide canal sign would be present only in isthmic spondylolisthesis, where the vertebral ring is disrupted by defects in the pars interarticularis.The midline sagittal MR images of 100 control subjects without spondylolysis or spondylolisthesis were analyzed to establish the normal range of sagittal canal diameters at the various lumbar levels. Midline sagittal MR images of the lumbar spine were reviewed in 53 patients in whom either isthmic (n = 35) or degenerative (n = 18) spondylolisthesis was confirmed with conventional radiography and/or CT. For each spinal level, the sagittal canal ratio, defined as the maximum anteroposterior diameter of the canal at that level divided by the diameter of the canal at L1, was calcul...
K2(NbO)2Si4O12: a new ferroelectric

The atomic coordinates of K2(NbO)2Si4O12 reported in space group P4bm satisfy the structural criteria for ferroelectricity. The estimated phase-transition temperature, Tc = 2230 (250) K, is substantially in excess of Tmelting = 1476 (5) K; the hypothetical paraelectric phase in space group P4/mbm is hence experimentally inaccessible. A strong indication that the phase transition does not occur at T < Tmelting is provided by the absence of both calorimetric and dielectric permittivity anomalies below Tmelting, the linear thermal dependence of unit-cell parameters with expansion coefficients α11 = –0.53 (12) × 10–6 and α33 = 24.66 (11) × 10–6 K–1 between 5 and 843 K, and the generation of second harmonics between 300 and 1353 K. Demonstration of dielectric hysteresis under both direct and alternating current, with spontaneous polarization Ps ≃ 0.2 C m–2, provides unambiguous verification of the ferroelectric property.
Empathy in schizophrenics, neurotics, and normals.

No significant differences were found between the group mean scores of 7 schizophrenics, 7 neurotics, and 7 normals on the Literature Empathy Test. However, there was support for the hypothesis that normals respond in terms of a generalized conventional other, while schizophrenics respond in a more idiographic manner.
Effect of in vitro incorporation of prostanoid precursors, superoxide radical and hydrogen peroxide on platelet function

Abstract The level of cyclic adenosine monophosphate (cAMP) in human platelets is known to be an important regulator of platelet function. The polyunsaturated fatty acids (PUFA) dihomo-gamma-linolenic acid (DHLA), and eicosapentaenoic acid (EPA), precursors of the prostaglandin (PG) 1 and 3 series respectively, were studied for their ability to stimulate platelet cAMP and/or PGE 1 levels, and to inhibit platelet aggregation (PAg). Incubation of washed platelets (1 × 10 8 /ml) with 125 μM DHLA increased intraplatelet levels of PGE 1 from 197±7 to 1622±9.7 picograms/10 8 , cAMP from 3±0.8 to 31±1.9 picomoles/10 8 , and inhibited collagen-induced PAg. Addition of 1 μmole of xanthine per unit of xanthine oxidase (a superoxide radical generating system) to the incubating medium potentiated the effects of both fatty acids, whereas 240 μM Hydrogen Peroxide (H 2 O 2 ) inhibited these effects. These results suggest that: (1) DHLA may be more effective in inhibiting PAg than EPA, which has been reported to reduce the incidence of coronary diseases in some human populations; (2) That superoxide radical may activate the platelet cyclooxygenase system to increase lipid peroxidation of these PUFA prostanoid precursors and may result in the inhibition of PAg, whereas H 2 O 2 may have an opposite effect.
Unique biosynthesis of dehydroquinic acid

A search of the genomic sequences of the thermophilic microorganisms Aquifex aeolicus, Archaeoglobus fulgidus, Methanobacterium thermoautotrophicum, and Methanococcus jannaschii for the first seven enzymes (aroG, B, D, E, K, A, and C ) involved in the shikimic acid biosynthetic pathway reveal two key enzymes are missing. The first enzyme in the pathway, 3-deoxy-d-arabino-heptulosonic acid 7-phosphate synthase (aroG) and the second enzyme in the pathway, 5-dehydroquinic acid synthase (aroB) are "missing." The remaining five genes for the shikimate pathway in these organism are present and are similar to the corresponding Escherichia coli genes. The genomic sequences of the thermophiles Pyrococcus abyssi and Thermotoga maritima contain the aroG and aroB genes. Several fungi such as Aspergillus fumigatus, Aspergillus nidulans, Saccharomyces cerevisiae, Schizosaccharomyces pombe, Pneumocystis carinii f. sp. carinii, and Neurospora crassa contain the gene aroM, a pentafunctional enzyme whose overall activity is equivalent to the combined catalytic activities of proteins expressed by aroB, D, E, K, and A genes. Two of these fungi also lack an aroG gene. A discussion of potential reasons for these missing enzymes is presented.
Computational comparisons of dual conjugate gradient algorithms for strictly convex networks

Abstract This paper presents a Lagrangian dual conjugate gradient algorithm for solving a variety of nonlinear network problems with strictly convex, differentiable, and separable objective functions. The proposed algorithm belongs to an iterative dual scheme, which converges to a point within a given tolerance-relative residual error. By exploiting the special structure of the network constraints, this approach is able to solve large problems with minimal computer memory requirements because no matrix operations are necessary. An extensive computational study has been carried out using different direction generators, line search procedures, and restart schemes. Two conjugate gradient direction formulas, the Polak-Ribiere and the memoryless BFGS, have been compared. In addition, two restart methods—the Beale's restart and the gradient restart—are tested for their effectiveness. A Newton method line search was tested against a bisection line search. Computational comparisons using statistical analysis have also been reported to illustrate the effectiveness of each combination of these procedures. The proposed method works well for network problems with quadratics, entropy, cubic, polynomial, and logarithm types of objective functions. Our computational experiments indicate that the most effective Lagrangian dual algorithm should include the combination of the Polak-Ribiere conjugate gradient formula, the Newton line search, and the gradient restart.
Validation of a Macroscopic Lane-Changing Model

Systematic lane changes inside a weaving area could lead to accidents and disrupt the entire traffic flow. Recently, a simple macroscopic lane-changing model that determines the number of lane changes from on-ramp flows and the number of lanes was proposed to describe traffic dynamics inside the lane-changing area at a merging section. However, this macroscopic lane-changing model had not been validated with vehicle trajectory data. This study attempted to fill that validation gap. First, lane changes were categorized into two types: left-lane changes and right-lane changes. Then the following two hypotheses derived from the macroscopic lane-changing model were validated: (a) the number of left-lane changes within two adjacent lanes linearly increases from the leftmost lane to the shoulder lane and (b) the number of left-lane changes linearly increases with the flow rate of on-ramp vehicles inside the lane-changing area. Traffic balance among lanes was analyzed, and the two proposed hypotheses were valida...
Positron Annihilation Spectroscopy for Chemical Analysis

Abstract The prediction and discovery of the existence of positron (e+)1-4 and positronium atom (Ps)5,6 led rapidly to the development of a new spectroscopic technique for the study of the structure and composition of matter. The technique quickly expanded across interdisciplinary from physics to chemistry, metallurgy, biochemistry and recently to superconductors. As an early non-destructive and in situ testing tool, positron annihilation spectroscopy (PAS) has been utilized extensively to measure crystal defects.7-9
Controlling acid deposition by seasonal gas substitution in coal- and oil-fired power plants

Based on evidence that the rate of wet sulfate deposition in eastern North America is higher in the summer half of the year than in the winter half, seasonal control of emissions is proposed as a means of minimizing acid deposition control costs. This paper evaluates the proposal that natural gas be substituted for coal and oil in electric power plants during April through September. A model is presented that simulates the substitution of natural gas for coal and oil in power plants in the eastern 31 state region, so as to minimize total costs with respect to deposition reductions at an Adirondack receptor. The results of the model show: 1) the increased effectiveness of seasonal versus year-round controls; 2) changes in fuel consumption levels as a result of substitution; and 3) the costs of achieving various levels of deposition reduction at an Adirondack receptor. The costs of seasonal gas substitution are compared to cost estimates for other proposed control methods. The conclusion is that seasonal gas substitution is cost-competitive with other control methods, at least in some plants and states.
S-nitrosylation of tissue-type plasminogen activator confers vasodilatory and antiplatelet properties on the enzyme

Abstract Tissue-type plasminogen activator (t-PA) reacts upon exposure to endothelium-derived relaxing factor (EDRF) by way of the enzyme's single free sulfhydryl (Cys-83) to form a stable S-nitrosothiol protein adduct. S-nitrosylation endows t-PA with potent vasodilatory and antiplatelet properties that are accompanied by elevations in intracellular cyclic GMP analogous to those induced by low molecular weight (e.g., S-nitroso amino acid) S-nitrosothiols. Moreover, this chemical modification does not adversely affect the catalytic efficiency of t-PA, the fibrin stimulation of this activity, the binding of t-PA to fibrinogen, or the interaction of the enzyme with its physiologic serine protease inhibitor, plasminogen-activator inhibitor type I. The coupling of vasodilatory, antiplatelet, and fibrinolytic properties in one molecule makes the S-nitrosylated t-PA a unique molecular species and may provide insight into the mechanisms by which the endothelium maintains vessel patency. These data also suggest a pharmacologic approach to treatment of thromboocclusive disorders.
Role of gap junctions and nitric oxide in control of myometrial contractility

T here are many mechanisms involved in the regulation of uterine contractility. The conversion of myometrial contractility during pregnancy f rom quiescence to an active and reactive state during labor, a condition dominated by rhythmic, synchronous and forceful contractility, is the result of a complex interaction of an array of systems and events. Normal labor, as well as abnormal, is thought to be preceded by a series of hormonal changes including deviations in levels of steroid hormones, prostaglandins, and cytokines. These episodes activate a number o f processes in the muscle cells that t ransform it to a higher level o f excitability and thereby modify it for contractions during labor. At the same time, there are decreases in mechanisms that depress contractility. In this article, we will briefly outline two systems thought to,be of great importance in regulating uterine contractility during pregnancy. One system consists of cell-to-cell conduction pathways termed "gap junct ions" which, when present, increase excitation of the myometrium. Many studies have shown that the formation and presence of gap junct ions between myometrial cells are necessary for labor, and the absence or closure of these specialized contacts favors inactivity. The other system is newly described and composed of an L-arginine-nitric oxide-cGMP pathway that suppresses contractility during pregnancy, but not during labor.
Using group-based trajectory modeling to examine heterogeneity of symptom burden in patients with head and neck cancer undergoing aggressive non-surgical therapy

Treatment-related symptom burden varies significantly among patients undergoing radiotherapy or chemoradiotherapy, yet such variation is typically not reflected in the results from single-group studies. We applied group-based trajectory modeling (GBTM) to describe the heterogeneity of symptom burden among patients with head and neck cancer and to identify subgroups with distinct symptom-development trajectories. Patients (n = 130) were recruited pretherapy and rated multiple symptoms weekly for 10 weeks via the M. D. Anderson Symptom Inventory. With the mean of five most severe symptoms over time as an outcome measure, GBTM was used to identify patient subgroups with distinct symptom trajectories. Linear mixed-effects modeling (LMM) was applied to compare with GBTM’s ability to describe the longitudinal symptom data. The five most severe symptoms were problems with taste, difficulty swallowing or chewing, problems with mucus, fatigue, and dry mouth. A two-group GBTM model identified 68 % of patients as having high symptom burden, associated with older age, worse baseline performance status, and chemoradiotherapy treatment. A four-group GBTM model generated one stable group (4 % of patients) and three groups varying in symptom severity with both linear and quadratic functions over time. LMM revealed symptom-change patterns similar to that produced by GBTM but was inferior in identifying risk factors for high symptom burden. For cancer patients undergoing aggressive therapy, GBTM is capable of identifying various symptom-burden trajectories and provides severity groupings that will aid research and may be of clinical utility. These results may be generalizable to other cancer types and treatments.
On the interpretation of the field theoretical potential in terms of phase shifts

Abstract The type of potential introduced by Schwinger in connection with quantum electrodynamics and adopted by Gupta for nucleon-nucleon interactions is being distinguished from the more usual type which is used in a Schrodinger equation involving the coordinates of interacting particles. The application of the Dyson S matrix expansion in terms of plane waves to the calculation of the collision matrix is justified by the consideration of wave packets. Explicit relationships between expressions occurring in Dyson's S in the usual notation and the collision matrix are listed and it is shown that a non-Hermitean potential can be written down which has the property of reproducing the scattering amplitude in first Born approximation. Explicit relations to the reactance matrix of nuclear reaction theory are listed and alternative procedures of calculating phase shifts and coupling parameters by means of the non-Hermitean potential are discussed. Relativistic correction factors are analyzed in a form distinguishing between factors occurring in general and those peculiar to pseudoscalar coupling for the second order potential. Attention is called in the concluding remarks to a formal similarity between the success of Dyson's S -operator expansion in quantum electrodynamics and the qualitative reproduction of phenomenological phase parameter fits by the S -operator in the nucleon-nucleon case.
Angiography and the pediatric trauma patient: a 10-year review.

Abstract Background/Purpose Although interventional radiology has played an increasing role in the management of adult trauma patients, little has been written regarding its application in the care of the injured child. This study analyzed the indications, results, and complications for angiography in pediatric trauma patients. Methods A retrospective review of pediatric patients (14 years or younger) admitted to Los Angeles County-University of Southern California Medical Center, Los Angeles, Calif (an urban level I trauma center), over a 10-year period (1993-2003) was performed. Patients who underwent angiography were identified using hospital angiography records, and further information was recorded from the trauma registry and medical records. Variables collected included age, sex, mechanism of injury, and injury severity score (ISS). Angiographic data analyzed included indications, results, therapeutic interventions, and procedure-related complications. Results Twenty-five pediatric trauma patients who underwent angiography were identified (18 boys, 7 girls). The average age was 11 years (range, 1-14 years), with an ISS of 16 ± 10. Indications for angiography included suspected limb ischemia (n = 9), suspected pelvic (n = 8) or solid organ bleeding (n = 8), suspected aortic injury (n = 6), and expanding hematoma (n = 1). Eleven patients (44%) had an abnormal finding, and 10 of 11 underwent a subsequent therapeutic intervention. There was 1 minor procedure-related complication and no procedure-related mortality. Conclusions Though used infrequently in pediatric trauma patients, the result of the angiography was abnormal in almost half of the children in this series. An abnormal finding prompted further therapeutic intervention in most cases. Angiography was associated with minimal morbidity and should be considered as a useful and safe adjunct when caring for injured children.