cssi/SciSciGPT-SciSciNet huggingface dataset:
Development of the Finite Segment Method for Modeling Railroad Track Structures

In the finite segment method, the dynamics of a deformable body is described using a set of rigid bodies that are connected by elastic force elements. This approach can be used, as demonstrated in this investigation, in the simulation of some rail movement scenarios. The purpose of this investigation is to develop a new track model that combines the absolute nodal coordinate formulation (ANCF) geometry and the finite segment method. The ANCF finite elements define the track geometry in the reference configuration as well as the change in the geometry due to the movement of the finite segments of the track. Using ANCF geometry and the finite segment kinematics, the location of the wheel/rail contact point is predicted online and used to update the creepage expressions due to the finite segment displacements and rotations. The location of the wheel/rail contact point and the updated creepage expressions are used to evaluate the creep forces. A three-dimensional elastic contact formulation (ECF-A), that allows for wheel/rail separation, is used in this investigation. The rail displacement due to the applied loads is modeled by a set of rigid finite segments that are connected by set of spring-damper elements. Each rail finite segment is assumed to have six rigid body degrees of freedom. The equations of motion of the finite segments are integrated with the railroad vehicle system equations of motion in a sparse matrix formulation. The resulting dynamic equations are solved using a predictor-corrector numerical integration method that has a variable order and variable step size. As shown in this paper, the finite segments may be used to model specific phenomena that occur in railroad vehicle applications, including rail rotations and gage widening. The procedure used in this investigation to implement the finite segment method in a general purpose multibody system (MBS) computer program is described. Four simple models are presented in order to demonstrate the implementation of the finite segment method in MBS algorithms. The limitations of using the finite segments approach for modeling the track structure and rail flexibility are also discussed.Copyright © 2011 by ASME
Relaxation effects in glassy selenium

Abstract Thermal relaxation phenomena were measured in samples of both melt-quenched and evaporated selenium. On the basis of earlier studies, the two methods of preparation produced samples with polymeric chain concentrations of 30–50% and 0% respectively; the rest of the material was in the form of eight member rings. The relaxation peak occurred between 320 and 330 K, and had an activation energy of ≈22.5 kcal/mole for the melt-quenched sample. A decrease of 1 K in the glass relaxation temperature and 0.5 kcal (a at) −1 in the activation energy was observed in samples which had been initially evaporated. No change was observed as a result of melting and quenching these evaporated samples. It is postulated that there was no change when the evaporated sample was melt-quenched be because rings and chains can interconvert and equilibrate relatively readily at temperatures as low as T g (50° C), and consequently the samples all had the same structure after once being heated above T g . The differences observed are probably due to accidental impurities in the evaporated samples which help catalyze the interconversion of rings and chains. Further, since the equilibrium concentration of polymeric chains is temperature dependent, it is postulated that the large relaxation effects seen at T T g are due to the equilibration of these chains with the rings. The observed activation energy for the relaxation supports this view. It is about the same energy as has been previously measured for Se 8 ring breaking in liquid selenium. Two consequences of this postulate are that the selenium analog to the sulfur polymerization transition must occur well below room temperature if it exists, and therefore, that the equilibrium ring-chain ratio can be smoothly extrapolated down to room temperature from the published high-temperature data.
L12-type ternary titanium aluminides as electron concentration phases

The structural change from aluminium-rich titanium aluminides (TiAl2 or TiAl3) to L12 type ternary titanium aluminides is examined in terms of the two alloying variables; these are atomic radius ratio (R A/R B) and electron concentration (e/a). Similarity in the stoichiometry of the L12 alloys (generally Ti25X8Al66 where X=Cr, Mn, Fe, Co, Ni, Pd, Ag or Zn) and the differences in the atomic radii of ternary alloying elements makes it difficult to useR A/R B criterion as an alloy variable. It is also found that the structural change in these alloys cannot be explained by the classical definition ofe/a because it gives an increase in this ratio rather than a decrease upon the addition of the ternary alloying element to TiAl2 or TiAl3. On the other hand, if a definition given by the Engel-Brewer theory is used, a decrease ine/a is found to occur upon the addition of ternary alloying element to either TiAl2 or TiAl3 with the consequence of achieving L12-type ternary titanium aluminides at definitee/a values around 2.5.
Dermal uptake of chloroform and haloketones during bathing

Dermal contact with some organic disinfection by-products (DBPs) such as trihalomethanes in chlorinated drinking water has been established to be an important exposure route. We evaluated dermal absorption of two haloketones (1,1-dichloropropanone and 1,1,1-trichloropropanone) and chloroform while bathing, by collecting and analyzing time profiles of expired breath samples of six human subjects during and following a 30-min bath. The DBP concentrations in breath increased towards a maximum concentration during bathing. The maximum haloketone breath concentration during dermal exposure ranged from 0.1 to 0.9 microg / m(3), which was approximately two orders of magnitude lower than the maximum chloroform breath concentration during exposure. Based on a one-compartment model, the in vivo permeability of chloroform, 1,1-dichloropropanone, and 1,1,1-trichloropropanone were approximated to be 0.015, 7.5 x 10(- 4), and 4.5 x 10(- 4) cm / h, respectively. Thus, haloketones are much less permeable across human skin under normal bathing conditions than is chloroform. These findings will be useful for future assessment of total human exposure and consequent health risk of these DBPs.
The Moral Economy of Tobacco

ABSTRACT Even faced with overwhelming evidence that tobacco threatens human health, along with economic developments undermining their status as independent producers, North Carolina tobacco farmers view tobacco production in ways congruent with a moral economy. A shift from independent to contract production of tobacco and the dismantling of government price supports have challenged this moral economy, converting tobacco producers into a quasi–working class dependent on tobacco companies while leading to fewer tobacco farms and an increase in the average tobacco farm's size. These changes signal a shift away from a moral economy of tobacco, although moral-economic dimensions remain. Producers today emphasize different moral dimensions of economic behavior, such as producing quality human beings, than during earlier eras, when moral-economic actors pressed for state intervention in economic crises. Moral-economic principles are not restricted to either non-Western or historical peoples but, rather, influence economic production and ideology in advanced capitalist settings today.
KINETICS OF CONFORMATIONAL CHANGES ASSOCIATED WITH POTASSIUM BINDING TO AND RELEASE FROM NA+/K+-ATPASE

The Na+K+-ATPase functions in cells to couple energy from the hydrolysis of ATP to the transport Na+ out and K+ in. The fluorescent probe IAF (iodoacetamidofluorescin) covalently binds to this enzyme, reporting conformational changes without inhibiting enzyme activity. This paper describes experiments using dog kidney enzyme labeled with IAF to examine kinetics of conformational changes resulting from added Na+ and K+, measured in terms of steady-state and stopped-flow fluorescence changes. Kinetics of these fluorescence changes were examined as a junction of temperature from two initial conditions: (a) enzyme in the high-fluorescence form (Ehigh) was rapidly mixed with varying [K+]; and (b) enzyme in the low-fluorescence form (Elow) was rapidly mixed with varying [ATP]. These experiments showed: (1) The rate constant for the fluorescence change from Ehigh to Elow was much larger than that for the opposite transition, Elow to Ehigh; (2) the apparent free energy of activation (Eaapp) for the two transitions were different (as estimated from Arrhenius plots); (3) under steady-state conditions, IAF fluorescence did not change when ATP was added to Elow(K+) in the absence of Na+; (4) the apparent free energy of activation was independent of [K+] for the Ehigh to Elow transition (at 16.4 kcal/mol) but increased with [ATP] for the Elow to Ehigh transition: (5) Eaapp for the Elow to Ehigh transition with 1 mM ATP was approximately the same as that in the absence of ATP (34 kcal/mol). These results can be interpreted as: (i) in the transition from Elow to Ehigh. IAF reported a conformational change that occurred after K+ release to the intracellular side and which is involved in Na+ binding; (ii) Eaapp increased with [ATP], while increasing the entropy of the transition state. Thus, ATP appeared to destabilize the enzyme during the transition from Elow to Ehigh.
Arithmetic cohomology over finite fields and special values of ζ-functions

We construct cohomology groups with compact support Hci(Xar,Z(n)) for separated schemes of finite type over a finite field which generalize Lichtenbaum's Weil-etale cohomology groups for smooth and projective schemes (see [22]). In particular, if Tate's conjecture holds, and rational and numerical equivalence agree up to torsion, then the groups Hci(Xar,Z(n)) are finitely generated, form an integral model of l-adic cohomology with compact support, and admit a formula for the special values of the ζ-function of X
Effectiveness and economics of dryland conservation tillage systems in the southern Great Plains

Precipitation is limited in the Southern Great Plains, and farmers must minimize production costs and control erosion. The purpose of this research was to determine economic feasibility of dryland no- and reduced-tillage systems compared with sweep plowing on Pullman clay loam soil (fine, mixed, mesic Torrertic Paleustoll) in continuous winter wheat (Triticum aestivum L. emend. Thell) and in a winter wheat-sorghum [Sorghum bicolor (L.) Moench]-fallow rotation with two crops produced in 3 yr. Economic analyses considered 4-yr averages of income and treatment costs. In continuous winter wheat, sweep plowing yielded significantly less (425 kg ha −1 ) than the best no-tillage treatment in 2 of 4 yr. Because of low variable costs, sweeping was most profitable in the short-term, and when machinery depreciation was considered for the long-term, sweep tillage followed by glyphosate lost the least money [...]
MHD enhanced vortex containment concept for a gas core nuclear rocket

An idea originally conceived of back in 1957, the use of hydrodynamic vortices as a fuel containment mechanism for a gas core nuclear rocket is revisited. The modification entails the use of externally applied electromagnetic fields to increase the vortex strength and overcome the pitfalls of the original concept. Power to drive the MHD system is provided via a heat engine operating on a Brayton cycle, drawing power from the reactor waste heat and depositing it into a radiator. A system study is performed to determine what performance can be expected, and results show that specific impulses up to and beyond 3000 seconds are obtainable, as well as thrust to weight ratios of order 10 and higher. Containment of the fuel is better than 1 part in 10000 lost out the nozzle, and energy transfer is very efficient since the propellant and fuel are made to diffuse through one another. The start-up requirement has the consequences of allowing the system to operate in a dual-mode role as a propulsive device and/or a power reactor.
Stable Interaction between β-Arrestin 2 and Angiotensin Type 1A Receptor Is Required for β-Arrestin 2-mediated Activation of Extracellular Signal-regulated Kinases 1 and 2

Binding of β-arrestins to seven-membrane-spanning receptors (7MSRs) not only leads to receptor desensitization and endocytosis but also elicits additional signaling processes. We recently proposed that stimulation of the angiotensin type 1A (AT1A) receptor results in independent β-arrestin 2- and G protein-mediated extracellular signal-regulated kinases 1 and 2 (ERK1/2) activation. Here we utilize two AT1A mutant receptors to study these independent pathways, one truncated at residue 324, thus removing all potential carboxyl-terminal phosphorylation sites, and the other bearing four mutations in the serine/threonine-rich clusters in the carboxyl terminus. As assessed by confocal microscopy, the two mutant receptors interacted with β-arrestin 2-green fluorescent protein with much lower affinity than did the wild-type receptor. In addition, the mutant receptors more robustly stimulated G protein-mediated inositol phosphate production. Approximately one-half of the wild-type AT1A receptor-stimulated ERK1/2 activation was via a β-arrestin 2-dependent pathway (suppressed by β-arrestin 2 small interfering RNA), whereas the rest was mediated by a G protein-dependent pathway (suppressed by protein kinase C inhibitor). ERK1/2 activation by the mutant receptors was insensitive to β-arrestin 2 small interfering RNA but was reduced more than 80% by a protein kinase C inhibitor. The biochemical consequences of ERK activation by the G protein and β-arrestin 2-dependent pathways were also distinct. G-protein-mediated ERK activation enhanced the transcription of early growth response 1, whereas β-arrestin 2-dependent ERK activation did not. In addition, stimulation of the truncated AT1A mutant receptor caused significantly greater early growth response 1 transcription than did the wild-type receptor. These findings demonstrate how the ability of receptors to interact with β-arrestins determines both the mechanism of ERK activation as well as the physiological consequences of this activation.
Competing for Liberty: The Republican Critique of Democracy

Freedom as non-domination has acquired a leading status in political science. As a consequence of its success, neo-roman republicanism also has achieved great prominence as the political tradition that delivered it. Yet despite the fact that liberty in the Roman mode was forged not only in direct confrontation with monarchy but against democracy as well, the relationship of republicanism to democracy is the great absentee in the contemporary debate on non-domination. This article brings that relationship back into view in both historical and conceptual terms. It illustrates the misrepresentations of democracy in the Roman tradition and shows how these undergirded the theory of liberty as non-domination as a counter to political equality as a claim to taking part in imperium. In so doing it brings to the fore the “liberty side” of democratic citizenship as the equal rights of all citizens to exercise their political rights, in direct or indirect form.
5.1.1 Overview of the EIA 632 Standard: Processes for Engineering a System

The EIA 632 standard has been developed that describes the “processes for engineering a system.” This standard evolved from EIA/IS 632—the interim standard that described a systems engineering process. This paper will describe the structure of the standard, elements of the process, and key concepts such as stakeholder requirements, enabling products, building blocks, and development layers.
s-d hybridization and evolution of the electronic and magnetic properties in small Co and Ni clusters

Photoelectron spectra of cold ${\mathrm{Ni}}_{n}^{\ensuremath{-}}$ and ${\mathrm{Co}}_{n}^{\ensuremath{-}}$ clusters revealed discrete electronic features for $nl10$ for Ni and 20 for Co. These features, mainly due to detachment of $4s$ electrons, merge with $3d$-derived features at larger cluster sizes, indicating the onset of significant s-d hybridization. The current results clearly revealed how the electronic structure of Ni and Co clusters evolves from molecular to bulklike in the early stage of cluster growth. They also provide insight into the origin of the enhanced magnetism in small Ni and Co clusters, due to the localized nature of the $3d$ electrons.
Comparison of Mg and Zn gate implants for GaAs n-channel junction field effect transistors

Zinc and magnesium implants into GaAs were profiled with secondary ion mass spectroscopy and etching capacitance-voltage to measure the as-implanted and annealed profiles for the eventual formation of shallow p+/n junction gates for junction field effect transistors (JFETs). The larger mass of the zinc ions results in shorter projected range with significantly less tailing than magnesium implants. High dose, shallow zinc implants annealed under tungsten gate metal showed good activation with negligible diffusion. The improved profile of the zinc implant, as compared to a similar magnesium implant, allowed a tighter JFET design with increased performance. Zn gated n-channel enhancement mode GaAs JFETs with 0.9 µm gate lengths showed transconductances up to 200 mS/ mm with a ft of 18 GHZ and a fmax of 37 GHz. The performance of these self-aligned fully implanted JFETs compare favorably with comparably sized implanted MESFETs.
Coronary computed tomography angiography for the detection of cardiac allograft vasculopathy: a meta-analysis of prospective trials.

Objectives This study aimed to evaluate the diagnostic accuracy of coronary computed tomography angiography (CCTA) for detecting cardiac allograft vasculopathy (CAV) in comparison with conventional coronary angiography (CCAG) alone or with intravascular ultrasound (IVUS). Background CAV limits long-term survival after heart transplantation, and screening for CAV is performed on annual basis. CCTA is currently not recommended for CAV screening due to the limited accuracy reported by early studies. Technological advances, however, might have resulted in improved test performance and might justify re-evaluation of this recommendation. Methods A systematic review of Medline, Cochrane, and Embase for all prospective trials assessing CAV using CCTA was performed using a standard approach for meta-analysis for diagnostic test and a bivariate analysis. Results Thirteen studies evaluating 615 patients (mean age 52 years, 83% male) and 9,481 segments fulfilled inclusion criteria. Patient-based analyses comparing CCTA versus CCAG for the detection of any CAV (> luminal irregularities) and significant CAV (stenosis ≥50%), showed mean weighted sensitivities of 97% and 94%, specificities of 81% and 92%, a negative predictive value (NPV) of 97% and 99%, a positive predictive value (PPV) of 78% and 67%, and diagnostic accuracies of 88% and 94%, respectively. There was a strong trend toward improved sensitivity (97% vs. 91%, p = 0.06) and NPV (99% vs. 97%, p = 0.06) to detect significant CAV with 64-slice compared with 16-slice CCTA. A patient-based analysis of 64-slice CCTA versus IVUS showed a mean weighted sensitivity and specificity of 81% and 75% to detect CAV (intimal thickening >0.5 mm), whereas the PPV and NPV were 93% and 50%, respectively. Conclusions CCTA using currently available technology is a reliable noninvasive imaging alternative to coronary angiography with an excellent sensitivity, specificity, and NPV for the detection of CAV.
Application of the Positive Reality Principle to Metal Electrode Linear Polarization Phenomena

The linear electrode-electrolyte polarization immittance (impedance or admittance) can be analyzed by the fractional power pole (FPP) model [38] based on the modification of Bode's [4] method to include functions with poles and/or zeros of fractional power. This is, in essence, an extension of the Davidson-Cole model [12] to the entire frequency spectrum. In this paper, the minimum phase property of the FPP model is verified and the positive reality principle [5] is used to identify the specific type of immittance function for which the FPP model is applicable. This condition is an extension of the "universal" law of dielectric response as advanced by Jonscher [26].
WISPAC: a parallel array computer for large-scale system simulation

This paper discusses the multiple-instruction stream/ multiple-data stream (MIMD) Wisconsin parallel array computer (WISPAC). The design of the computer makes use of current, low-cost microprocessor technology and is intended to meet future needs in large-scale simulation. A modular approach is taken where smaller configurations are meant as direct competi tive replacements of current hybrid systems. Larger configurations will allow high-speed solution of large-scale simulation problems using a one-to-one correspondence of each microprocessor to each node of the system being modeled. A three-dimensional configuration is used to allow a high degree of iso morphism between the computer setup and the model to be investigated. These schemes simplify programming requirements and overall machine conceptualization. New techniques of high-speed internode communication utilizing a serial "pass-through" scheme are des cribed. The scheme allows general cross-array com munication that is competitive with cross-point ...
Sickle cell disease and hydroxyurea: the good, the bad, and the future

Comment on Bakanay et al, page [545][1] Even treated with hydroxyurea, severe sickle cell anemia has higher mortality than milder disease. Understanding how early in the disease process this treatment can be safely started is now paramount. The outlook for patients with sickle cell disease has
Ballistocardiography. I. Physical considerations.

A physical analysis is presented of the Starr, Nickerson, and Dock methods for registering the ballistocardiogram. It is shown that many forms of distortion are present. Some of the distortion may be present in the instrumentation which may be controlled, and other forms of distortion are inherent in the subject under test which are most difficult to control or evaluate. The effects which some of the uncontrollable variables have upon the amplitudes and temporal positioning of the registered ballistocardiographic waves is analyzed. The status of static and dynamic standardization procedures is discussed. A "Glossary of Technical Terms" is appended.
A model incorporating energy utilization for the dynamics of single species populations

Abstract A model for the population dynamics of a single species of animals is developed. The model consists of three ordinary differential equations expressing the rates of change of the state variables: density of animals, mean biomass per animal and food density; and several algebraic equations. The model differs from previous models in that mean biomass is used as an index of the size-age structure of the population, energy utilization by the population is considered, and a dimensionless form is developed. Terms are included for food supply rates and harvest rates. The results of computer simulations are presented and the properties of the model, including its stability and sensitivity to varying the parameters and initial conditions are discussed.
Wear resistance of isosit and polymethyl methacrylate occlusal splint material

Abstract Simulated occlusal wear utilizing the artifical mouth included natural enamel against isosit and polymethyl methacrylate splint materials. The results reported in volume loss (mm 3 ) demonstrated the isosit material to be 55–67% more resistant to wear than polymethyl methacrylate. No wear occurred on the enamel surface opposing either splint material.
Why data sharing should be the expected norm

The Institute of Medicine takes a step in the right direction but we should move even faster
Magmatic evolution of Hekla, Iceland

The extrusive rocks of Hekla are predominantly flows of basaltic andesite and andesite (icelandite) but each eruptive cycle is initiated by production of tephra of andesitic, dacitic, and even rhyolitic composition. The evolution of basaltic andesites to dacites and rhyolites can be explained by crystallization and (presumably gravitative) separation of olivine, titaniferous magnetite, plagioclase, and probably augite. No contamination by sialic crustal material is required.
Changes in the ventilation of the southern oceans

Changes in the ventilation of the southern oceans over the past few decades are examined using ocean measurements of CFC-12 and model simulations. Analysis of CFC-12 measurements made between the late 1980s and late 2000s reveal large-scale coherent changes in the ventilation, with a decrease in the age of subtropical Subantarctic Mode Waters (SAMW) and an increase in the age of Circumpolar Deep Waters. The decrease in SAMW age is consistent with the observed increase in wind stress curl and strength of the subtropical gyres over the same period. A decrease in the age of SAMW is also found in Community Climate System Model version 4 perturbation experiments where the zonal wind stress is increased. This decrease is due to both more rapid transport along isopycnals and the movement of the isopycnals. These results indicate that the intensification of surface winds in the Southern Hemisphere has caused large-scale coherent changes in the ventilation of the southern oceans.
The Meanings and Messages of Las Vegas: The Present of our Future

Las Vegas is studied as an arguably prototype postmodern space to develop some understanding of (post)modern consumption. Analyses indicate that while Las Vegas has several characteristics that may help a deeper understanding of the modern and of conditions that signal transformations toward the postmodern, it is far from being a postmodern space. The hegemony of the market and the insistence of the commercial hinder the development of the postmodern. However, insights into the nature of Las Vegas as excess, the change in the status of motion and speed (which are now ends in themselves rather than means to arrive at a destination), and the consumer inclinations for immersion into themes observed in Las Vegas provide explanations that will help a better understanding of contemporary cultural trends.
Inter-regional endogenous growth under the impacts of demographic changes

This article attempts to project the economic paths for the individual Midwest states (Illinois, Indiana, Michigan, Ohio and Wisconsin, as well as the rest of the US) in the near future when the population ageing becomes more pronounced. To accomplish this task, a dynamic general equilibrium model is developed so that it could incorporate the inter-regional transactions and endogenous growth mechanisms within the framework of an Overlapping Generations (OLG) model. Key parameter values associated with the regional interconnections were assigned using a multi-regional Social Accounting Matrix (SAM) of the Midwest states. Two different steady-state results were presented with two different age-cohort population structures corresponding to year 2007 and 2030. These steady-state results imply that the rate of declining of per-capita output is projected to be heterogeneous across the regions due to different developments of age-cohort population structures and consequently different levels of endogenously dete...
Transcription initiation and temporal expression of thymidine kinase mRNA in Chinese hamster cells.

Abstract The induction of thymidine kinase mRNA has proved to be a valuable model for understanding regulatory events at the G1 S boundary of the cell cycle (1, 2, 3). As an initial step toward characterizing the regulation of this gene in Chinese hamster cells, I have mapped the transcription start sites for TK mRNA in CHEF 18 cells. Two closely spaced sites of transcription initiation were detected downstream of a nonconsensus TATAA element in the promoter region. Using primer extension analyses, I demonstrated that the transcription initiation sites remained constant while the absolute levels of TK mRNA varied during the cell cycle in synchronized populations of Chinese hamster cells.
The binding of exogenous juvenile hormone by the haemolymph of Oncopeltus fasciatus

Constituents of the haemolymph of the milkweed bug, Oncopeltus fasciatus, bind exogenously applied juvenile hormone. Data from Sephadex gel filtration, preparative isoelectric focusing and charcoal assay suggest that juvenile hormone is bound to at least two large molecular weight lipoproteins. In vitro and in vivo studies confirm the binding of the labeled hormone to these proteins. Developmental studies indicate that similar proteins are present in the fourth and fifth instars. It is demonstrated that binding artifacts may be generated when gel filtration is used as the only means of analysis.
A preliminary study of sonographic grading of fetal intracardiac echogenic foci: feasibility, reliability and association with aneuploidy.

Objectives To prospectively and quantitatively grade intracardiac echogenic focus/foci (ICEF) using sonographic gain reduction and to determine the association of ICEF by grade with fetal aneuploidy. Methods Women referred for raised maternal age (≥ 35 years), or > 18 years of age and with a Down syndrome risk ≥1/270, increased trisomy 18 risk by second trimester serum screen or a prior aneuploid offspring were included in this institutionally approved protocol. Only pregnancies of gestational age between 14 and 24 weeks were included. All women had a targeted ultrasound and were offered fetal chromosome analysis. The classification of ICEF was made from a four-chamber view of the fetal heart. The echo amplitude of the ICEF was compared to that of the thoracic spine and categorized according to the comparative gain setting at which the image of the relevant structure disappeared: Grade O = no ICEF present, Grade 1 = ICEF image lost before thoracic spine when gain was reduced, Grade 2 = ICEF image lost at same gain setting as thoracic spine, Grade 3 = thoracic spine image lost before ICEF. The primary outcome was a prenatally or post-natally detected chromosomal abnormality. Results A total of 885 eligible women were examined during the 21-month study period. ICEF were seen in 29 (3.3%) fetuses: 24(83%) in the left ventricle and five (17%) in the right ventricle. A chromosome abnormality was identified in 13/671 (1.9%) fetuses without ICEF (Grade 0) and 0/21 (0%) fetuses with Grade 1 ICEF. In contrast, two of five (40%) fetuses with Grade 2 ICEF were aneuploid (P = 0.005). No Grade 3 ICEF were observed. Additional sonographic abnormalities were seen in both aneuploid fetuses with Grade 2 ICEF. Interobserver agreement on ICEF grading was noted in 50/50 (100%) examinations (kappa = 1.0). Conclusions Sonographic grading of ICEF is feasible and highly reliable. Grade 2 ICEF, especially when accompanied by additional sonographic markers of a chromosomal abnormality, are associated with aneuploidy significantly more frequently than Grade 1 ICEF. Copyright © 2000 International Society of Ultrasound in Obstetrics and Gynecology
Activity of new receptors after transection of the primary olfactory nerve in pigeons.

Abstract Recent findings indicate that surgical interruption of an animal's olfactory nerve causes the receptor cells to degenerate and that subsequently a population of new receptor neurons is derived from basal cells of the olfactory epithelium. The return of function was studied electrophysiologically after the primary olfactory nerves of 26 pigeons were transected bilaterally. No sign of neural life was found 6–15 days after neural resection in 6. No response to amyl acetate but spontaneous neural activity was recorded 8–15 days after surgery in 4. Detectable responsiveness to 10 −1.0 vapor saturation of amyl acetate was seen 17–28 days postoperatively in 7. Responses, diminishing rapidly during successive inspirations, to all concentrations except 10 −3.0 amyl acetate were recorded 19, 25 and 30 days postoperatively in 3. Normal sensitivity and responsiveness to the initial inhalation of amyl acetate were found 29, 31, 58, 89, 123 and 185 days postoperatively in 6. These results delineate a temporal course of functional recovery and suggest that a normal population of functioning receptors can be re-established by about 30 days.
A second form of actin: platelet microfilaments depolymerized by ATP and divalent cations.

Abstract A 45,000-dalton protein has been isolated from platelet actomyosin by sucrose gradient centrifugation or Sepharose 6-B column chromatography in the presence of Ca-ATP. It has been characterized as actin on the basis of (i) comigration with actin during gel electrophoresis in sodium dodecyl sulfate or in urea at pH 9.5 and 2.4, (ii) its amino acid composition, which includes about 1 mole of 3-methylhistidine per 45,000 g, and (iii) its ability to form 7-nm-thick microfilaments that bind rabbit muscle heavy meromyosin to produce characteristic arrowhead structures. This protein can be distinguished from other actins by the conditions for polymerization-depolymerization; it depolymerizes under conditions used to polymerize other actins and it polymerizes in the absence of ATP and divalent cations. On the basis of polymerization properties we propose that conventional actin, also present in platelets, has a direct contractile function while the second form of actin is primarily structural.
Initiation of surface cracks in multilayer ceramic thermal barrier coatings under thermal loads

Abstract The initiation of surface cracks in thick ceramic thermal barrier coatings systems was studied by using controlled experiments and the corresponding analysis. The experimental boundary conditions consisted of a concentrated heat flux at the surface of the coating and water cooling at the bottom of the substrate. The results showed that tensile stresses were formed at the surface during cooling following stress relaxation during steady state heating. A parametric study showing that a low Young's modulus and a low coefficient of thermal expansion for the coating would reduce these tensile stresses and increase its durability.
Measuring corticotropin‐releasing hormone in pregnant women – comparing blood collection protocols for epidemiological studies

We describe a pilot study to determine the effect of delays in blood sample processing under simulated field conditions on measurement of corticotropin-releasing hormone (CRH) levels in pregnant women. CRH, a peptide secreted by the placenta into the maternal blood, is of interest in epidemiological studies of gestational duration. Many investigators suspected that CRH might break down quickly after collection, and believed the optimal treatment of blood samples for CRH must include immediate processing under chilled conditions and quick freezing of plasma. Epidemiological studies often have logistical constraints that make such rapid processing unfeasible. To examine how delays in the processing of blood samples might affect the level of measured CRH, we collected whole blood samples from 33 pregnant women attending a prenatal clinic in Boston. We compared CRH levels measured following three different processing delays with the levels of samples that were processed immediately after blood collection, the 'gold standard'. The delayed strategies involved placing the freshly collected whole blood in a cooler or refrigerator for up to 22 h prior to processing. Correlation coefficients comparing delayed with gold standard processing exceeded 0.96. These results suggest that CRH may be measured in blood samples that were spun and frozen up to 22 h after blood collection.
Comparative efficacies of amphotericin B, triazoles, and combination of both as experimental therapy for murine trichosporonosis

We assessed the activities of amphotericin B deoxycholate, liposomal amphotericin B, fluconazole, and SCH 39304 against 10 strains of Trichosporon beigelii in mice with hematogenous infections. Cyclophosphamide-immunosuppressed CF1 male mice were challenged intravenously with a lethal inoculum of T. beigelii (5 x 10(6) conidia per mouse) and were assigned to different treatment groups or were left untreated. Amphotericin B deoxycholate (1 mg/kg of body weight and liposomal amphotericin B (1, 5, and 10 mg/kg) were given parenterally once daily. Escalating doses (5, 10, and 20 mg/kg/day) of fluconazole and SCH 39304 were tested. We also compared the activity of amphotericin B deoxycholate plus fluconazole (1 and 10 mg/kg/day, respectively) with that of each agent alone. Fluconazole significantly prolonged the survival of mice infected with each of the 10 strains tested. Amphotericin B deoxycholate achieved various responses, improving the outcomes in mice infected with seven of the strains. Liposomal amphotericin B was not more effective than amphotericin B deoxycholate against the two strains tested. Both fluconazole and SCH 39304 reduced the kidney fungal counts in a dose-dependent pattern, with SCH 39304 being more active than fluconazole against one of the two strains tested. The activity of the combination of amphotericin B deoxycholate plus fluconazole appeared to be superior to that of either agent alone, especially in reducing the kidney fungal burden. Fluconazole is more active than amphotericin B deoxycholate against experimental murine trichosporonosis.
THE IMPACT OF ENHANCED INCENTIVES ON VOCATIONAL REHABILITATION OUTCOMES FOR DUALLY DIAGNOSED VETERANS

This study evaluated the efficacy of adding contingency management techniques to vocational rehabilitation (VR) to improve treatment outcome as measured by entry into competitive employment. Nineteen dually diagnosed veterans who entered VR in the Veterans' Administration's compensated work therapy (CWT) program were randomly assigned to CWT (n = 8) or to CWT with enhanced incentives (n = 11). Over the first 16 weeks of rehabilitation, those in the incentives condition could earn up to $1,006 in cash for meeting two sets of clinical goals: (a) remaining abstinent from drugs and alcohol and (b) taking steps to obtain and maintain a competitive job. Results indicate that relative to participants in the CWT-only group, those in the incentives condition engaged in more job-search activities, were more likely to remain abstinent from drugs and alcohol, were more likely to obtain competitive employment, and earned an average of 68% more in wages. These results suggest that rehabilitation outcomes may be enhanced by restructuring traditional work-for-pay contingencies to include direct financial rewards for meeting clinical goals.
Renal failure associated with the use of celecoxib and rofecoxib.

Objective: Celecoxib and rofecoxib are two relatively new nonsteroidal anti-inflammatory drugs (NSAIDs) that selectively inhibit the cyclo-oxygenase-2 (COX-2) isoenzyme at therapeutic concentrations. The nephrotoxic potential of selective COX-2 inhibitors has not been clearly established. This study was conducted in order to understand the association between acute renal failure and the two COX-2 inhibitors celecoxib and rofecoxib. Methods: A search was performed in the US Food and Drug Administration’s (FDA) Adverse Event Reporting System (AERS) to identify cases of renal failure submitted to the FDA. A MEDLINE search of the English language literature was also performed to identify published cases of renal failure associated with celecoxib and rofecoxib. Results: One hundred twenty-two and 142 domestic US cases of celecoxib and rofecoxib-associated renal failure, respectively, were identified in the AERS database. The literature search identified 19 cases of acute renal impairment in association with celecoxib and rofecoxib. In addition, drug regulatory authorities in the UK, Canada, and Australia have received about 50 reports of renal failure with celecoxib and rofecoxib. Descriptive statistics of the AERS cases have been summarised in this report. Conclusions: Data from AERS and published case reports suggest that use of both these drugs is associated with renal effects similar to that of conventional nonselective NSAIDs. Physicians should be aware that serious or life-threatening renal failure has been reported in patients with normal or impaired renal function after short-term therapy with celecoxib and rofecoxib. Patients at greatest risk for renal injury are those with pre-existing renal impairment, heart failure, liver dysfunction, those taking diuretics and/or ACE inhibitors, and the elderly. Kidney function should be monitored closely for any signs of potential renal injuries soon after initiating treatment with these agents, especially in high-risk populations. In addition, healthcare practitioners should adequately warn patients of the signs and symptoms of serious renal toxicity, and of the need for them to see their physician promptly if they occur. Celecoxib and rofecoxib are not recommended for use in patients with advanced renal disease.
Ca2+ Inhibition of Cation Conductance through TRPV1 Receptors

TRPV1 receptors are polymodal cation channels that show a marked permeability to Ca2+. In the present study, we used single channel electrophysiology and whole cell patch clamp photometry to further study the interaction of extracellular Ca2+ ([Ca2+]o) with the recombinant TRPV1 receptor expressed in HEK293 cells. In the presence of and 140 mM [NaCl]o, we observed that [Ca2+]o attenuates the amplitude of capsaicin (0.5 microM)-evoked single channel currents through TRPV1 receptors within a physiologically relevant concentration range (Kd = 2 mM, Hill slope = 1.1). The inhibition was observed at a range of positive and negative membrane potentials, being more pronounced at negative potentials. Use of patch clamp photometry revealed that at −60 mV in the presence of 10 mM [Ca2+]o, which is almost maximally effective for inhibiting single channel current amplitudes (56%), the fractional of the current carried by Ca2+ current was only 40%. Thus, Na+ still carries most of the cation current through the TRPV1 receptor even when Ca2+ is likely occupying the site responsible for its inhibiting cation conductance. Finally, we observed that neutralizing the charge on single amino acids located in the mouth of the putative pore and known to contribute to Ca2+ selection by TRPV1 receptors, Asp646, Glu648 and Glu651, did not alter the inhibitory effect of 2 mM [Ca2+]o. To summarize, although Ca2+ has been reported to increase the open probability of TRPV1 receptors, this divalent cation also attenuates conductance through the channel pore via an unknown mechanism seemingly discreet from that contributing to the high Ca2+ permeability of these receptors.
Does health predict the reporting of racial discrimination or do reports of discrimination predict health? Findings from the National Longitudinal Study of Youth.

Racial discrimination may contribute to diminished well-being, possibly through stress and restricted economic advancement. Our study examines whether reports of racial discrimination predict health problems, and whether health problems predict the reporting of racial discrimination. Data come from years 1979 to 1983 of the US National Longitudinal Study of Youth, focusing on respondents of Black (n = 1851), Hispanic (n = 1170), White (n = 3450) and other (n = 1387) descent. Our analyses indicate that reports of racial discrimination in seeking employment predict health-related work limitations, although these limitations develop over time, and not immediately. We also find that reports of discrimination at two time-points appear more strongly related to health-related work limitations than reports at one time-point. A key finding is that these limitations do not predict the subsequent reporting of racial discrimination in seeking employment. These findings inform our knowledge of the temporal ordering of racial discrimination in seeking employment and health-related work conditions among young adults. The findings also indicate that future research should carefully attend to the patterns and timing of discrimination.
Linear and Nonlinear Relationships between Neuronal Activity, Oxygen Metabolism, and Hemodynamic Responses

We investigated the relationship between neuronal activity, oxygen metabolism, and hemodynamic responses in rat somatosensory cortex with simultaneous optical intrinsic signal imaging and spectroscopy, laser Doppler flowmetry, and local field potential recordings. Changes in cerebral oxygen consumption increased linearly with synaptic activity but with a threshold effect consistent with the existence of a tissue oxygen buffer. Modeling analysis demonstrated that the coupling between neuronal activity and hemodynamic response magnitude may appear linear over a narrow range but incorporates nonlinear effects that are better described by a threshold or power law relationship. These results indicate that caution is required in the interpretation of perfusion-based indicators of brain activity, such as functional magnetic resonance imaging (fMRI), and may help to refine quantitative models of neurovascular coupling.
Quality Improvement and Efficiency of Care: Are Acronyms Really the Way of the Future?

Quality improvement has become an increasingly important focus of health care over the last decade. In an effort to systematically improve quality, several organizations and programs have been developed, each known by a different acronym. This article describes the origins, mission, and methodology of the organizations and programs that have been established to standardize performance and improve quality. The role of these programs in health care, and the way they affect individual surgeons in practice, is then discussed.
Jaltomata II: new combinations for five South American species (Solanaceae)

The following species, originally described in the genusSaracha Ruiz & Pav., are transferred toJaltomata, in accordance with contemporary generic boundaries.Jaltomata auriculata (Miers) Mione is distributed from Venezuela to Peru;J. contorta (Ruiz & Pav.) Mione andJ. diversa (J. F. Macbr.) Mione both occur in Peru;J. herrerae (C. V. Morton) Mione is distributed in Peru and Bolivia;J. nitida (Bitter) Mione occurs in Venezuela.
Studies of the Commitment Step in the Germination of Spores of Bacillus Species

Spores of Bacillus species are said to be committed when they continue through nutrient germination even when germinants are removed or their binding to spores' nutrient germinant receptors (GRs) is both reversed and inhibited. Measurement of commitment and the subsequent release of dipicolinic acid (DPA) during nutrient germination of spores of Bacillus cereus and Bacillus subtilis showed that heat activation, increased nutrient germinant concentrations, and higher average levels of GRs/spore significantly decreased the times needed for commitment, as well as lag times between commitment and DPA release. These lag times were also decreased dramatically by the action of one of the spores' two redundant cortex lytic enzymes (CLEs), CwlJ, but not by the other CLE, SleB, and CwlJ action did not affect the timing of commitment. The timing of commitment and the lag time between commitment and DPA release were also dependent on the specific GR activated to cause spore germination. For spore populations, the lag times between commitment and DPA release were increased significantly in spores that germinated late compared to those that germinated early, and individual spores that germinated late may have had lower appropriate GR levels/spore than spores that germinated early. These findings together provide new insight into the commitment step in spore germination and suggest several factors that may contribute to the large heterogeneity among the timings of various events in the germination of individual spores in spore populations.