cssi/SciSciGPT-SciSciNet huggingface dataset:
Cyclooxygenase-2-derived Prostaglandin E2 Directs Oocyte Maturation by Differentially Influencing Multiple Signaling Pathways

The process of oocyte maturation, which impacts ovulation and fertilization, is complex and requires an integration of the endocrine, paracrine, juxtacrine, and autocrine signaling pathways. This process involves an intimate interaction between the oocyte and encircling cumulus cells within a follicle, a unique venue for somatic and germ cell communication. Cumulus cell expansion and resumption of meiosis with germinal vesicle breakdown are major events in oocyte maturation. Cyclooxygenase-2 (COX-2)-derived prostaglandin E2 (PGE2) is a known critical mediator of oocyte maturation, but the diverse function of this lipid mediator in oocyte maturation, ovulation, and fertilization has not been fully appreciated. We show here that gonadotropins in coordination with PGE2 signaling via its cell surface G-protein-coupled EP2 and EP4 receptor subtypes direct cumulus cell expansion and survival and oocyte meiotic maturation by differentially impacting cAMP-dependent protein kinase, MAPK, NF-κB, and phosphatidylinositol 3-kinase/Akt pathways. This study is unique in the sense that it provides evidence for new site- and event-specific involvement of these signaling pathways under the influence of COX-2-derived PGE2 during the critical stages of this somatic-germ cell interaction, an absolute requirement for oocyte maturation.
Normal embryonic stages for salmonid fishes, based on Salmo gairdneri Richardson and Salvelinus fontinalis (Mitchill)

As a byproduct of a re-examination of teleost morphogenetic movements, 23 stages in the normal development of salmonid fishes are presented, from fertilization to and beyond hatching, together with rates of their appearance at several constant temperatures. To aid in planning experiments, the period before closure of the germ ring is divided into 13 stages, with detailed discussion of internal structures and movements as well as external features, especially during gastrulation. The literature of salmonid development suggests that the stages are closely applicable to the embryos of any genera of Suborder Salmonoidei. except as to the rates of their appearance. Illustrations are designed for ready identification of stages. Tofacilitate their correlation with the older morphological literature, the principal events of organogenesis in the ectodermal, mesodermal, and endodermal categories are listed according to the stages at which they occur, as determined by dissections and serial sections.
Losartan was more effective than atenolol for isolated systolic hypertension and left ventricular hypertrophy.

Source Citation Kjeldsen SE, Dahlof B, Devereux RB, et al. Effects of losartan on cardiovascular morbidity and mortality in patients with isolated systolic hypertension and left ventricular hypertr...
What is the best strategy to combat low bone mineral density in functional hypothalamic amenorrhea

What is the best strategy to combat low bone mineral density in functional hypothalamic amenorrhea?
Proteolysis of tau by calpain

The calpain-induced proteolysis of tau associated with twice-cycled microtubules or from a total brain heat-stable fraction was studied. Twice-cycled microtubule tau was rapidly hydrolyzed by calpain. In contrast, tau purified from the total brain heat-stable fraction was very resistant to degradation by calpain. These results clearly demonstrate that there are at least 2 populations of tau in the brain based on calpain-sensitivity, a calpain-sensitive form that is associated with microtubules and a calpain-resistant form that may represent another population of tau in the brain.
Complications of Mechanical Ventilation — The CDC's New Surveillance Paradigm

New CDC surveillance definitions for ventilated patients aim both to broaden the focus of surveillance beyond pneumonia to include other common complications and to increase objectivity to facilitate automation, improve comparability, and minimize gaming.
Energy Decomposition Analyses for Many-Body Interaction and Applications to Water Complexes

Two algorithms for many-body interaction energy decomposition within the Hartree−Fock approximation are presented. These two schemes, which are extensions of the two-body Kitaura−Morokuma (KM) analysis and the reduced variational space self-consistent-field (RVS SCF) method, decompose the interaction energy into electrostatic, exchange, polarization, and charge transfer components. The Hartree-Fock interaction energies for the optimum water dimer, trimer, and tetramer were analyzed in terms of two-, three-, and four-body terms of these individual components. Counterpoise calculations of the exchange and charge transfer components proposed by Tomasi were performed to estimate the basis set superposition errors. The results show that the three-body nonadditive terms of water trimer and tetramer are dominated by the polarization and charge transfer components at their optimized structures with various basis sets and that the four-body term of water tetramer is very small. The RVS SCF energy components, whose...
A regression-based approach to scalability prediction

Many applied scientific domains are increasingly relying on large-scale parallel computation. Consequently, many large clusters now have thousands of processors. However, the ideal number of processors to use for these scientific applications varies with both the input variables and the machine under consideration, and predicting this processor count is rarely straightforward. Accurate prediction mechanisms would provide many benefits, including improving cluster efficiency and identifying system configuration or hardware issues that impede performance.We explore novel regression-based approaches to predict parallel program scalability. We use several program executions on a small subset of the processors to predict execution time on larger numbers of processors. We compare three different regression-based techniques: one based on execution time only; another that uses per-processor information only; and a third one based on the global critical path. These techniques provide accurate scaling predictions, with median prediction errors between 6.2% and 17.3% for seven applications.
Detection of deep vein thrombosis by 125I-labelled fibrinogen scanning technique--a methodological study.

Abstract Although 125I-labelled fibrinogen scanning technique for the detection of deep vein thrombosis has been validated by angiography, it is not known whether 20% (or 15%) of heart count indicates a fixed amount of fibrin deposition in all individuals. The range of variation in fibrin deposition compatible with a positive leg scan (Minimum Fibrin) has been examined in 26 patients who underwent abdominal operations. Minimum Fibrin was found to vary tenfold in these 26 patients. This wide variation in Minimum Fibrin arises from a similar variation in the concentration of fibrinogen in blood. In addition, Minimum Fibrin increases with time after operation, partly due to an increase in the concentration of fibrinogen and partly due to an accumulation of isotope in the extravascular space. As a consequence the 125I-labelled fibrinogen method favours detection of small thrombi in the immediate postoperative period and is biased against detection of similar sized thrombi later in the postoperative period.
Quantitative diagnosis of bladder cancer by morphometric analysis of HE images

In clinical practice, histopathological analysis of biopsied tissue is the main method for bladder cancer diagnosis and prognosis. The diagnosis is performed by a pathologist based on the morphological features in the image of a hematoxylin and eosin (HE) stained tissue sample. This manuscript proposes algorithms to perform morphometric analysis on the HE images, quantify the features in the images, and discriminate bladder cancers with different grades, i.e. high grade and low grade. The nuclei are separated from the background and other types of cells such as red blood cells (RBCs) and immune cells using manual outlining, color deconvolution and image segmentation. A mask of nuclei is generated for each image for quantitative morphometric analysis. The features of the nuclei in the mask image including size, shape, orientation, and their spatial distributions are measured. To quantify local clustering and alignment of nuclei, we propose a 1-nearest-neighbor (1-NN) algorithm which measures nearest neighbor distance and nearest neighbor parallelism. The global distributions of the features are measured using statistics of the proposed parameters. A linear support vector machine (SVM) algorithm is used to classify the high grade and low grade bladder cancers. The results show using a particular group of nuclei such as large ones, and combining multiple parameters can achieve better discrimination. This study shows the proposed approach can potentially help expedite pathological diagnosis by triaging potentially suspicious biopsies.
Corroborative Study on Maize Quality, Dry-Milling and Wet-Milling Properties of Selected Maize Hybrids

A corroborative study was conducted on the maize quality properties of test weight, pycnometer density, tangential abrasive dehulling device (TADD), time-to-grind on the Stenvert hardness tester (SHT), 100-kernel weight, kernel size distribution, and proximate composition as well as maize dry- and wet-millability by six participating laboratories. Suggested operating procedures were given to compare their measurements and provide the variance structure within and between laboratories and hybrids. Partial correlation coefficient among maize quality properties varied among laboratories. The repeatability and reproducibility precision values were acceptably low for the physical quality tests, except for TADD and SHT time-to-grind measurements. The yields of dry- and wet-milled products and their correlation with maize quality properties were dependent on the collaborating laboratory. This paper highlights the importance of laboratory variation when considering which maize hybrids are best suited for dry-milling and wet-milling.
THE NATURE OF THE UPPER 400 KM OF THE EARTH AND ITS POTENTIAL AS THE SOURCE FOR NON-BIOGENIC PETROLEUM

It has been reported that the upper 400 km of the Earth outgassed 1015 tons of petroleum-related fluid over the past 3 billion years. By assuming Fischer-Tropsch reactions and crustal entrapment, 0.1% of this quantity can account for the entire amount of petroleum estimated to be in the Earth's crust. In this paper, the authors attempt to define in some detail the past and present nature of this deep-source for non-biogenic petroleum. The principal data used are seismic, and the nature of the matter that is found totally enclosed in natural diamonds from world-wide continental sources. New data are presented on matter included in diamond cubes from Zaire, Africa, noteworthy among which are the identification of plagioclase, silicate glass, and solid hydrocarbon inclusions. The general conclusions on the upper 400 km of the Earth are: (1) Diamonds, the sample carriers from the inner Earth, formed over the depth range <= 70 <= 370 km in a partially molten silicate environment that contained C and H components. (2) From top to bottom, the growth environment varied from aqueous, carbonate-rich and felsic to aqueous, hydrogen-rich and ultramafic. (3) Petroleum and petroleum-forming constituents were present throughout. (4) The depth range of diamond formation is found to correlate with the present depth profile of the suboceanic asthenosphere. Because of this, it is concluded that the general nature of this region of the Earth has not changed much since the earliest known time of diamond formation (~3 b.y. ago) in spite of material transport to the surface and isostatic adjustment of the lithosphere-asthenosphere boundary. The discovery of significant solid hydrocarbon in a diamond cube suggests that the hydrocarbon content of the upper region of the asthenosphere may be twice that indicated by occluded fluid alone. This tends to support a suggestion based on the quantity of occluded fluid in kimberlite that 1016 rather that 1015 tons of petroleum and petroleum-forming material have outgassed from the Earth during the past 3 billion years. An outgassing of 1016 tons would have permitted crustal accumulation of up to 105 tons per km in a 10-million year span of Cenozoic time, consistent with the existence of Cenozoic petroleum fields. By analogy with N2 outgassing, it is estimated that about 1015 tons of non-biogenic petroleum remain to be outgassed from the Earth.
The Clostridium cellulovorans cellulosome

AbstractThe Clostridium cellulovorans cellulosome is comprised of a large, nonenzymatic scaffolding protein called the cellulose binding protein A (CbpA) and a number of endoglucanases/xylanases. The CbpA contains several functional domains, including a signal peptide, a cellulose binding domain (CBD), a hydrophilic domain (HBD) present four times, and a hydrophobic domain (HBD) present nine times. The functions of the domains were studied by the construction of minigenes containing the putative functional domains and by expression of the minigenes in Escherichia coli. The purified product of the CBD was able to bind to various crystalline forms of cellulose and chitin with a Kd. of 1 μM The binding capacity for CBD was a function of the crystallinity of the cellulose sample. Furthermore, the binding of CBD to Avicel was not inhibited by cellobiose or carboxymethylcellulose, suggesting that the CBD binding target was a three-dimensional structure found only in crystalline forms of cellulose. The HBD was t...
Scientists Track Sulfate Emissions Across Time

Scientists have a precise record of sulfate deposition from volcanoes stretching back 2000 years, a finding that will better inform future climate models and policy decisions. The new reconstruction was detailed in a paper published online on 6 July in Nature Climate Change (doi:10.1038/nclimate2293).
Estimating betas from nonsynchronous data

Abstract Nonsynchronous trading of securities introduces into the market model a potentially serious econometric problem of errors in variables. In this paper properties of the observed market model and associated ordinary least squares estimators are developed in detail. In addition, computationally convenient, consistent estimators for parameters of the market model are calculated and then applied to daily returns of securities listed in the NYSE and ASE.
Evidence for a central substructure in a Lumbricus terrestris hemoglobin obtained with STEM low-dose and digital processing techniques.

Applications of scanning transmission electron microscope (STEM) low-dose and digital image processing techniques to the annelid extracellular hemoglobin of Lumbricus terrestris have shown the existence of a central substructure. The techniques involve low-dose STEM images of less than 2 e / 2 irradiation. Many such low-dose images were then aligned in their symmetry, N -fold averaged, and summed. The central substructure appears to be supported by spokes which are connected to a surrounding hexagonal bilayer of 12 subunits. In comparison to the summed image of Nephtys hombergii hemoglobin which is known to possess a central substructure, the morphology of both central mass and spokes were very similar. This finding of a central substructure is consistent with the report of a small angle X-ray scattering study (Pilz et al. , 1980, Int. J. Biol. Macromol. 2 , 279–283) which predicted the possible existence of substructure in the center of the molecule.
Update on Adjuvant Chemotherapy for Early Breast Cancer

Breast cancer is the second most common cancer in women worldwide. Although most women are diagnosed with early breast cancer, a substantial number recur due to persistent micro-metastatic disease. Systemic adjuvant chemotherapy improves outcomes and has advanced from first-generation regimens to modern dose-dense combinations. Although chemotherapy is the cornerstone of adjuvant therapy, new biomarkers are identifying patients who can forego such treatment. Neo-adjuvant therapy is a promising platform for drug development, but investigators should recognize the limitations of surrogate endpoints and clinical trials. Previous decades have focused on discovering, developing, and intensifying adjuvant chemotherapy. Future efforts should focus on customizing therapy and reducing chemotherapy for patients unlikely to benefit. In some cases, it may be possible to replace chemotherapy with treatments directed at specific genetic or molecular breast cancer subtypes. Yet, we anticipate that chemotherapy will remain a critical component of adjuvant therapy for years to come.
Ischaemic preconditioning preferentially increases protein S-nitrosylation in subsarcolemmal mitochondria

Nitric oxide (NO) and protein S-nitrosylation (SNO) have been shown to play important roles in ischaemic preconditioning (IPC)-induced acute cardioprotection. The majority of proteins that show increased SNO following IPC are localized to the mitochondria, and our recent studies suggest that caveolae transduce acute NO/SNO cardioprotective signalling in IPC hearts. Due to the close association between subsarcolemmal mitochondria (SSM) and the sarcolemma/caveolae, we tested the hypothesis that SSM, rather than the interfibrillar mitochondria (IFM), are major targets for NO/SNO signalling derived from caveolae-associated eNOS. Following either control perfusion or IPC, SSM and IFM were isolated from Langendorff perfused mouse hearts, and SNO was analysed using a modified biotin switch method with fluorescent maleimide fluors. In perfusion control hearts, the SNO content was higher in SSM compared with IFM (1.33 ± 0.19, ratio of SNO content Perf-SSM vs. Perf-IFM), and following IPC SNO content significantly increased preferentially in SSM, but not in IFM (1.72 ± 0.17 and 1.07 ± 0.04, ratio of SNO content IPC-SSM vs. Perf-IFM, and IPC-IFM vs. Perf-IFM, respectively). Consistent with these findings, eNOS, caveolin-3, and connexin-43 were detected in SSM, but not in IFM, and IPC resulted in a further significant increase in eNOS/caveolin-3 levels in SSM. Interestingly, we did not observe an IPC-induced increase in SNO or eNOS/caveolin-3 in SSM isolated from caveolin-3(-/-) mouse hearts, which could not be protected with IPC. In conclusion, these results suggest that SSM may be the preferential target of sarcolemmal signalling-derived post-translational protein modification (caveolae-derived eNOS/NO/SNO), thus providing an important role in IPC-induced cardioprotection.
An approximate algorithm for the reanalysis of structures by the finite element method

Abstract An approximate computational algorithm is derived which permits a refined element analysis to be altered on a small capacity computer. The intent of the algorithm is to permit frequent design changes on any small computing machine where the computer cost is low and the machine-designer interaction is essentially instantaneous. The method is based upon the dynamic normal mode method and upon an accompanying solution technique known as ·dynamic relaxation”. Geometric and material alterations, including the effects of material nonlinearities, are permissible design changes within the normal mode approach. The design alteration leads to a system of uncoupled nonlinear equations whose numerical solution is economical in terms of both computing time and core storage.
Some comments on majority rule equilibria in local public good economies

Abstract This paper examines some of the main assumptions and results of the literature on majority rule equilibrium in local public good economies. It is shown that the usual assumption that the ordering of agents' MRSs between the private and public good is a continuous, monotone function of income and independent of the other economic variables is not necessary for an MRE to exist. In addition, it is shown that in economies with “home ownership”, stratification of agents by income or preferences need not occur in equilibrium.
A discrepancy measure for improved clustering

A discrepancy measure is proposed to improve the clustering of patterns which experience non-linear distortions. The discrepancy measure is an outcome of a non-linear alignment procedure which optimally aligns the elements of patterns in order to minimize the dissimilarity between the patterns. The K-means clustering algorithm is modified to use the discrepancy measure to compute the similarity between patterns and the cluster centers. A series of clustering experiments were conducted on identical data using the modified and standard K-means algorithm. The results obtained show that clustering performance of the modified algorithm is significantly superior to that of the standard algorithm.
Selective HIFU Foaming to Fabricate Porous Polymer for Tissue Engineering Scaffolds

A novel technique is presented in this paper for the fabrication of tissue engineering scaffolds using the High Intensity Focused Ultrasound (HIFU). This acoustic method is a solvent-free, highly efficient and low cost process that has the potential in scaffold-based tissue engineering. HIFU fabrication technique is capable of creating hierarchically-structured porous polymeric materials, which have various topographical features at different length scales. This will in turn affect the cellular response and behavior of certain type of cells, such as the integration and growth of smooth muscle cells (SMCs). In this study, the effect of HIFU porous polymer fabrication was investigated. Scanning-mode HIFU insonation was performed in the HIFU polymer foaming experiments. The acoustic power and the scanning speed were chosen as the parameters and varied in different groups of experiments. The created microstructures were characterized using the scanning electron microscopy (SEM). The fabricated samples were used for cell culture studies with human aortic SMCs (Passage 4). It was found that the selective HIFU foaming process could be used to create hierarchical structures by choosing appropriate ultrasound parameters. The SMCs were viable on the HIFU-created porous PMMA specimens, and the topographical nature of a HIFU-created porous structure affected the cellular response of SMCs.Copyright © 2006 by ASME
Characterization and formation of submicron particles in coal-fired plants

Abstract Submicron particles resulting from pulverized coal combustion in coal-fired steam plants have been chemically characterized and the results interpreted in terms of various mechanisms for their formation. Elemental analyses using XRF, AA, and INAA techniques are reported for approximately 60 elements for flyash from two large coal-fired plants. The concentrations of elements volatilized during combustion are independent of particle size in the submicron size range, in contrast to the larger particle sizes where an inverse relationship with particle size applies. Scanning electron micrographs show the submicron particles are also much more homogeneous than larger flyash particles, while still showing evidence of some surface enrichment in ESCA studies. Various mechanisms for formation of submicron particles have been considered. The present results are most consistent with formation of submicron particles by the bursting of larger particles due to gas release during rapid heating, followed by coagulation and condensation of volatilized elements to form particles in the 0.1–1.0 μm size range. The importance of this mechanism in other coal-fired plants is probably dependent on both temperature and ash composition.
Cardiopulmonary responses to experimental venous carbon dioxide embolism

Background: Although the low-flow CO2 insufflation rate used to initiate pneumoperitoneum may reduce the severity of potential venous embolism, its safety is not established.
toward a science of politics

In the first half of the essay we summarise the main contributions in the essays in this issue by Coleman, Colomer, and Taagepera, and identify key commonalities in their suggestions for making political science more ‘scientific’. We argue that most of their concerns are well taken, but that the remedies they propose may not be applicable in all domains within political science. In particular, it is largely in the area of voting and elections, where clearly demarcated input and output variables can be identified, that their suggestions seem the most applicable. In the second half of the essay we trace the rise and fall, over the past 100 years, of movements in the US to make political science more scientific. We conclude by identifying similarities between these essays and the recent EITM movement in US political science.
Structure and Composition of the Mantle

The last four years have been a period of increased emphasis on the problems of discontinuities, lateral variations, and shear velocities in the mantle. The presence of discontinuities near 400 km and 600 km has been verified by travel time, apparent velocity, and reflection and amplitude studies; it has been shown by refraction and reflection amplitudes that these discontinuities are extremely sharp, 4 km or less. Other discontinuities, or abrupt changes in velocity gradient, have been found in the upper and lower mantle. It now appears that there are relatively few large radial stretches of the mantle that are truly homogeneous. A summary of the locations of discontinuities in the mantle is given in Johnson [1967] and Whitcomb and Anderson [1970]. A second-order discontinuity has been found near 500 km by Helmberger and Wiggins [1971].
Prenatal exposure to medroxyprogesterone acetate (MPA) in girls.

Abstract (1) Studies on the long-term effects of progesterone administration during gestation have suggested that it has a mild influence on postnatal female behavior causing even greater femininity than expected in normal controls. (2) However, it has been difficult to distinguish the effects of the prenatal hormone from those of the maternal disease state (toxemia). (3) In a new study, girls (n= 15) with prenatal exogenous hormonal exposure due to maternal intake of medroxyprogesterone acetate (MPA) were compared with a closely matched control group. (4) The results suggested that MPA was not associated with genital abnormalities in genetic females. (5) Behavior effects of prenatal MPA appeared to be subtle and included a lower incidence of being labeled a tomboy during childhood and a more constant preference for feminine clothing styles. (6) We conclude that prenatal MPA may have an enhancing effect on female sexually dimorphic behavior.
Dynamics of the PKA C-Subunit Major Conformational States Using REXAMD

Molecular dynamics simulations can yield insight into the role of protein dynamics in allostery and binding cooperativity. Recent work by Masterson et al. (reference 1) on protein kinase A (PKA) has shown that the binding of ATP and the substrate-like inhibitor PKI to the catalytic sub-unit is highly cooperative. Various biochemical techniques identified specific residues important to the allosteric network. We present replica exchange accelerated molecular dynamics (REXAMD) simulations of the different states of the PKA catalytic sub-unit, linking the protein dynamics with the known cooperativity.References:1) Masterson, L. R.; Mascioni, A.; Traaseth, N. J.; Taylor, S. S.; Veglia, G. Proceedings of the National Academy of Sciences 2008, 105, 506-511.
Surface morphology studies of Y-Ba-Cu-oxide thin films prepared by pulsed organometallic beam epitaxy

Abstract Pulsed organometallic beam epitaxy is a new technique for the deposition of complex metal oxide films. With this technique each metal precursor species is sequentially pulsed onto the substrate. The flux of the precursor is monitored and computer feedback control is used to adjust the size of each precursor pulse, allowing precise control of the metal stoichiometry. Smooth films of YBa 2 Cu 3 O 7−δ , as examined by SEM, can be made with this technique in a temperature range that includes 640–680 °C using the β-diketonate precursors, Y(dipivalolymethanate) 3 , Ba(hexafluoroacetylacetonate) 2 -tetraglyme, and Cu(acetylacetonate) 2 . The morphology of the films is dependent on the ratio of the three precursors delivered to the substrate. The ratio of the three precursors must be held to better than +-10% in order to produce smooth films. The ratio between the three precursors needed to produce a smooth film changes with the deposition temperature. The relative amount of yttrium precursor delivered to the substrate must be decreased as the temperature is increased in order to maintain a smooth film. The metal composition of the smooth films is Y 1 Ba 2 Cu 3 (±4%).
Desmogleins 1 and 3 in the Companion Layer Anchor Mouse Anagen Hair to the Follicle

Anchorage of the hair to its follicle is of paramount importance for survival of rodents in the wild, and is aberrant in some human alopecias. Little is understood about the mechanisms responsible for hair shaft anchorage. Desmoglein (Dsg)3-/- (knockout) mice lose hair during telogen, but their anagen hairs remain anchored to the follicle. We hypothesized that Dsg1 compensates for the loss of Dsg3 in the anagen hair follicles of these Dsg3-/- mice. Consistent with this hypothesis, we found Dsg1 and Dsg3 expression overlapping in the companion layer. To functionally address this hypothesis, we used exfoliative toxin A (ETA) to inactivate Dsg1 in Dsg3-/- mice. Four hours after injection of ETA, Dsg3-/- mice, but not Dsg3+/+ or Dsg3+/- mice, showed striking loss of anagen hair, which was confirmed and quantitated by gentle tape stripping. Histology of the skin of these mice as well as of the tape-stripped hair showed separation between the outer root sheath and inner root sheath of the hair follicle, at the plane of the companion layer. Immunostaining for trichohyalin and K6, which highlights the companion layer, in skin and stripped hair confirmed the plane of separation. Labeling of proliferating cells with bromodeoxyuridine demonstrated that the matrix keratinocytes responsible for producing the hair shaft were below the split and remained in the follicle after loss of the anagen hair. These findings demonstrate the importance of the companion layer, and particularly the Dsg1 and Dsg3 in this layer, in anchoring the anagen hair to the follicle.
Effects of Quantization of Time-of-Flight (TOF) Measurements on Image Signal-to-Noise Ratio in TOF Emission Tomography

An effort to predict the signal-to-noise ratio performance in positron-emission tomography as a function of the number of levels used in quantizing the time-of-flight measurement has been undertaken. Conditions are identified under which the time-of-flight measurement and the error due to quantization are virtually uncorrelated. A simulation of time-of-flight tomography is undertaken to check the mathematical approximations of the analytical approach.
The angular diameters, effective temperatures, radii, and luminosities of 10 Wolf-Rayet stars

The effective temperature of a normal star with an absorption-line spectrum is a parameter which represents the total amount of radiative energy emerging from each square centimeter of surface of the star. Effective temperatures have been obtained for 10 Wolf-Rayet stars by means of ultraviolet energies determined from high-resolution International Ultraviolet Explorer (IUE) spectra and energies determined from observations made in the visible range. It is essential to use high-resolution IUE spectra in order to resolve the continuum from many emission lines which are present, particularly shortward of 1900 A. The results confirm what was found earlier, namely that the effective temperatures of Wolf-Rayet stars are similar to those of early B stars. The effective temperature of the central star of the planetary nebula BD 30 deg 3639, HD 184738, is found to be 18,000 K.
Cardiovascular and respiratory effects of tiletamine-zolazepam.

Abstract The combination of tiletamine and zolazepam is an important dissociative anesthetic-tranquilizer. However, little is known about the effects of this combination on the heart and respiration in rats. Adult, male rats anesthetized with tiletamine-zolazepam alone or tiletamine-zolazepam combined with xylazine or butorphanol were evaluated for changes in heart rate, mean arterial blood pressure, arterial blood pH, and blood gases during a 75-min period of anesthesia. Rats anesthetized with tiletamine-zolazepam had increased mean arterial blood pressure and less respiratory depression than did rats anesthetized with sodium pentobarbital. Tiletamine-zolazepam combined with xylazine at either dose produced bradycardia and a marked hypotension that persisted throughout the 75-min period. This combination produced respiratory depression comparable to tiletamine-zolazepam alone. The addition of butorphanol to tiletamine-zolazepam caused a transient hypotension and bradycardia. Tiletamine-zolazepam plus butorphanol produced a mild to severe respiratory depression that was dose and time dependent. These results demonstrate that: a) Tiletamine-zolazepam is cardiostimulatory, a property consistent with the known cardiovascular effects of other dissociative anesthetics; b) xylaxine plus tiletamine-zolazepam is a potent cardiovascular depressant combination; and c) tiletamine-zolazepam plus butorphanol at specific doses is an anesthetic-analgesic combination with minimal effects on cardiovascular and respiratory function.
Critical current characteristics of composite thin films of Au and YBa2Cu3O7

Abstract Thin film composites of YBa 2 Cu 3 O 7 (YBCO) with gold were deposited by inverted cylindrical magnetron sputtering on SrTiO 3 (STO), MgO, and yttrium stabilized zirconium (YSZ) substrates using a bilayer deposition process. The material and electrical properties of crystal structure, surface morphology, resistivity, transition temperature ( T c ), resistance ratio, and critical current ( I c ) as a function of temperature and small magnetic fields were investigated. Films deposited on STO showed little degradation in superconducting properties up to 500 A of gold with 1 kA of YBCO; for YSZ and MgO, the films showed a rapid fall-off in T c with gold thickness. For YSZ, 3–10 A of gold caused the films to become insulating; however, for gold greater than 25 A, the films were superconducting but T c rapidly fell to zero by 500 A of gold. Composites on MgO showed the most rapid fall-off in T c going to zero by 200 A of gold. The temperature dependence of I c was predominately quadratic. However, some films showed a crossover between quadratic and linear temperature dependence in I c . The I c of all the composites showed a response to small magnetic fields with the films on STO being the least sensitive and those on MgO the most. There was a trade-off between T c and field response with the film having the greatest response having the lowest T c . These composite films show potential for vortex flow device development.
Cluster simulation of itinerant magnetism

Abstract This paper discusses the reasons for undertaking exact calculations for model Hamiltonians defined on a cluster of atoms, and surveys the results obtained in some such studies (described in more detail elsewhere) for a simple Hubbard model. Principal emphasis is placed on an octahedral cluster. The ground state is characterized as a function of band filling and interaction strength, and the results obtained are discussed from the point of view of occupancy of single particle states.
Biochemical characterization of programmed cell death in NGF-deprived sympathetic neurons.

Young sympathetic neurons die when deprived of nerve growth factor (NGF). Under such circumstances, cell death is appropriate to the developing nervous system and requires RNA and protein synthesis. We have hypothesized the existence of an endogenous death program within neurons that is suppressed by trophic factors. The extent and timing of required changes in the synthetic events that comprise the death program are unknown. In an effort to characterize the biochemical events that mediate the death program further, we performed several experiments on embryonic rat sympathetic neurons in vitro. The death program was blocked with cycloheximide when total protein synthesis was inhibited ≥80%. When protein synthesis was inhibited within 22 ± 4 h of NGF deprivation, death was prevented in half the neurons. Hence, we define the commitment point for protein synthesis to be 22 ± 4 h. Analogously, the commitment point for RNA synthesis was 26 ± 4 h and that for NGF rescue, 24 ± 4 h. We tested the ability of a wide variety of chemicals to interfere with the death program. Most compounds tested were unable to prevent neuronal death. Some treatments, however, did save NGF-deprived neurons and were subsequently characterized. These included ultraviolet light and agents that raise intracellular concentrations of cAMP. Finally, we looked for the neuronal expression in vitro and in vivo of genes that have been associated with programmed death in other cell types, including TRPM-2/SGP-2, polyubiquitin, TGFβ-1, c-fos, and c-myc. None of these genes showed significant activation associated with neuronal death. © 1992 John Wiley & Sons, Inc.
Partial purification and characterization of nitrous oxide reductase from Paracoccus denitrificans

We report the first partial purification of nitrous oxide reductase, a unique and labile enzyme of denitrifying bacteria. The procedure, which required anaerobic conditions throughout, resulted in a 60-fold purification relative to crude lysate in the case ofParococcus denitrificans. The molecular weight was estimated by gel exclusion chromatography to be about 85,000. The partially purified enzyme is inactivated rapidly by O2, dithionite, and mercaptoethanol and is reversibly inhibited by moderate concentrations of common salts. Up to 80% of the original activity can be reconstituted following O2 inactivation by incubating the enzyme with reduced benzyl viologen for 2 to 3 h. TheV max pH profile shows a broad maximum at pH 8. The enzyme is irreversibly retained by common anion exchangers in the range pH 7 to 8 but can be eluted in acceptable yield as one of the last components from an imidazole-based anion exchange material by means of a pH gradient. This behavior implies that nitrous oxide reductase is very acidic. Among the several peptides observed by sodium dodecyl sulfate slab electrophoresis, only two, with apparent molecular weights of 58,000 and 25,000, correlated closely with the activity of fractions eluted from the imidazole column. These two peptides together comprised about 30% of the total protein in the fractions with highest specific activity.
A suite of Google services for daily course evaluation

In almost all institutions, students are asked to evaluate the quality of instruction on end-of-semester surveys. Unfortunately, these come too late to affect the quality of instruction in the current semester. They are essentially summative-evaluating what has already happened, mostly for the benefit of third parties, rather than formative-providing information that an instructor can use to improve teaching in the current class. Now, with the advent of freely accessible tools for taking Web surveys, it is easy to obtain formative feedback. This paper reports on a suite of Google forms and Google spreadsheets, along with a Google app for visualizing the results. These Google tools can be used to solicit feedback daily from a set of students in the class. This helps the instructor to keep tabs on how the students react to each class session, and compare the results with the feedback from previous class sessions.
Trends in post–liver transplant survival in patients with hepatitis C between 1991 and 2001 in the united states

It has been suggested that the post-liver transplantation (LT) survival rate of patients with hepatitis C virus infection (HCV) has declined in recent years. To compare the outcome of LT in patients with HCV at various time intervals between 1991 and 2001, we used United Network for Organ Sharing data to compare the post-LT survival of adult patients (age >18 years) with HCV with those without HCV. Of the 37,101 patients who underwent LT during the study period, 28,193 patients (HCV 7,459 and 20,734 non-HCV) were eligible for the study. On the basis of the time of transplantation, patients were divided into 3 groups: 1991-1993 (period 1), 1994-1997 (period 2), and 1998-2001 (period 3). The patient and graft survival rates were adjusted for other known confounding variables that influenced outcomes. The 3-year patient survival rate was lower in HCV patients compared with non-HCV recipients (78.5% vs. 81.4%, hazard ratio 1.14, 95% confidence interval 1.05-1.23, P = 0.001). The graft (72.8%, 71.0%, and 69.8%) and patient (77.4%, 79.6%, and 78.5%) survival of HCV patients remained unchanged during study periods 1-3, respectively. However, the graft and patient survival rates of non-HCV recipients improved markedly during study periods 2 and 3 compared with period 1. The graft and patient survival has remained unchanged between 1991 and 2001 in HCV recipients, but during the same period, there was a great improvement in survival among non-HCV recipients.
Synthesis and electrochemistry of 1,1′-bis(phosphino)cobaltocenium compounds

Abstract The electrochemistry of 1,1′-bis(diphenylphosphino)cobaltocenium hexafluorophosphate ([dppc][PF6]), 1,1′-bis(dicyclohexylphosphino)cobaltocenium hexafluorophosphate ([dcpc][PF6]), 1,1′-bis(di-iso-propylphosphino)cobaltocenium hexafluorophosphate ([dippc][PF6]), and 1-(di-tert-butylphosphino)cobaltocenium hexafluorophosphate ([1-dtbpc][PF6]) was examined in methylene chloride with tetrabutylammonium hexafluorophosphate as the supporting electrolyte. A reversible reductive wave followed by an irreversible wave at more negative potentials was observed. Ten new phosphinothioyl ([dppcS2][PF6], [dcpcS2][PF6], [dippcS2][PF6], [1-dtbpcS][PF6], and 1,1′-bis(dicyclohexylphosphinothioyl)ferrocene) and phosphinoselenoyl derivatives ([dppcSe2][PF6], [dcpcSe2][PF6], [dippcSe2][PF6], [1-dtbpcSe][PF6], and 1,1′-bis(dicyclohexylphosphinoselenoyl)ferrocene) were prepared and characterized, and the structures of eight of these compounds were determined. The electrochemistry of these phosphinochalcogenyl cobaltocenium compounds, as well as the previously prepared [dppcO2][PF6], displayed two reversible reductive waves at potentials less negative than that of the free phosphines. A correlation was found to exist between the Hammett substituent constant σp and the reduction potentials of these compounds. In addition, the phosphinoselenoyl [dppcSe2][PF6], [dcpcSe2][PF6], and [dippcSe2][PF6] displayed an electrochemically irreversible oxidative wave, potentially indicating an intramolecular Se–Se bonded trication. The electrochemistry of three new and five previously reported transition metal complexes of the general formula [MnCl2(P∩P)][PF6] (M = Pd or Pt, n = 1, P∩P = dppc, dcpc or dippc; M = Au, n = 2, P∩P = dppc or dcpc)) was also examined displaying at least two reductive waves at potentials less negative than that of the free phosphines. Comparison of the electrochemical data with that previously obtained for analogous ferrocenes indicates that a correlation exists between the reduction potentials of the cobaltocenium phosphines and the potentials at which oxidation of the ferrocene phosphines occurs. In addition, the structure of [Au2Cl2(dppc)][PF6] was determined.
Peer Assessment in Small Groups: A Comparison of Methods

This article describes and evaluates several peer evaluation tools used to assess student behavior in small groups. The two most common methods of peer assessment found in the literature are rating scales and single score methods. Three peer evaluation instruments, two using a rating scale and one using a single score method, are tested in several management courses to examine their effectiveness. All three instruments demonstrate acceptable levels of reliability and are found to be correlated with individual performance measures. The article concludes with a discussion of the advantages and disadvantages of each instrument.
Measuring learning gain during a one-day introductory bronchoscopy course.

Background Rigorous assessment of medical knowledge and technical skill inspires learning, reinforces confidence, and reassures the public. Identifying curricular effectiveness using objective measures of learning is therefore crucial for competency-oriented program development in a learner-centric educational environment. The aim of this study was to determine whether various measures of learning, including class-average normalized gain, can be used to assess the effectiveness of a one-day introductory bronchoscopy course curriculum. Methods We conducted a quasi-experimental one-group pre-test/post-test study at the University of California, Irvine. The group comprised 24 first-year pulmonary and critical care trainees from eight training institutions in southern California. Class-average normalized gain, singlestudent normalized gain, absolute gain, and relative gain were used as objective measures of cognitive knowledge and bronchoscopy technical skill learning. A class-average normalized gain of 30% was used to determine curricular effectiveness. Perceived educational value using Likertscale surveys and post-course questionnaires was determined during and 3 months after course participation. Results Mean test scores of cognitive knowledge improved significantly from 48 to 66% (p = 0.043). Absolute gain for the class was 18%, relative gain was 37%, class average normalized gain hgi was 34%, and the average of the single-student normalized gains g(ave) was 29%. Mean test scores of technical skill improved significantly from 43 to 77% (p = 0.017). Absolute gain was 34%, relative gain was 78%, class average normalized gain hgi was 60%, and the average of the single-student normalized gains g(ave) was 59%. Statistically significant improvements in absolute gain were noted in all five elements of technical skill (p \ 0.05). Likert-scale surveys, questionnaires, and surveys demonstrated strong perceived educational value. Conclusion The effectiveness of a one-day introductory bronchoscopy curriculum was demonstrated using a pretest/post-test model with calculation of normalized gain and related metrics.
Microglial Activation Resulting from CD40-CD40L Interaction After β-Amyloid Stimulation

Alzheimer's disease (AD) has a substantial inflammatory component, and activated microglia may play a central role in neuronal degeneration. CD40 expression was increased on cultured microglia treated with freshly solublized amyloid-beta (Abeta, 500 nanomolar) and on microglia from a transgenic murine model of AD (Tg APPsw). Increased tumor necrosis factor alpha production and induction of neuronal injury occurred when Abeta-stimulated microglia were treated with CD40 ligand (CD40L). Microglia from Tg APPsw mice deficient for CD40L demonstrated reduction in activation, suggesting that the CD40-CD40L interaction is necessary for Abeta-induced microglial activation. Finally, abnormal tau phosphorylation was reduced in Tg APPsw animals deficient for CD40L, suggesting that the CD40-CD40L interaction is an early event in AD pathogenesis.