cssi/SciSciGPT-SciSciNet huggingface dataset:
Coffee consumption and risk of endometrial cancer: Findings from a large up‐to‐date meta‐analysis

Several epidemiological studies have examined the association between coffee drinking and risk of endometrial cancer. To provide a quantitative assessment of this association, we conducted a meta-analysis of observational studies published up to October 2011 through a search of MEDLINE and EMBASE databases and the reference lists of retrieved article. Pooled relative risks (RRs) with 95% confidence intervals (CIs) were calculated using a random-effects model, and generalized least square trend estimation was used to assess dose-response relationships. A total of 16 studies (10 case-control and six cohort studies) on coffee intake with 6,628 endometrial cancer cases were included in the meta-analysis. The pooled RR of endometrial cancer for the highest versus lowest categories of coffee intake was 0.71 (95% CI: 0.62-0.81; p for heterogeneity = 0.13). By study design, the pooled RRs were 0.69 (95% CI: 0.55-0.87) for case-control studies and 0.70 (95% CI: 0.61-0.80) for cohort studies. By geographic region, the inverse association was stronger for three Japanese studies (pooled RR = 0.40; 95% CI: 0.25-0.63) than five studies from USA/Canada (pooled RR = 0.69; 95% CI: 0.60-0.79) or eight studies from Europe (pooled RR = 0.79; 95% CI: 0.63-0.99). An increment of one cup per day of coffee intake conferred a pooled RR of 0.92 (95% CI: 0.90-0.95). In conclusion, our findings suggest that increased coffee intake is associated with a reduced risk of endometrial cancer, consistently observed for cohort and case-control studies. More large studies are needed to determine subgroups to obtain more benefits from coffee drinking in relation to endometrial cancer risk.
On several types of convergence and divergence in Archimedean Riesz spaces

Abstract In the paper we define (and study the basic properties of) several concepts of convergence, divergence, and unboundedness in Archimedean Riesz spaces. The notions which we introduce will be used in order to obtain an extension of the Ornstein ratio ergodic theorem in a forthcoming paper.
Protected Designation of Origin as a Certified Quality System in the Andalusian olive oil industry: Adoption factors and management practices

Protected Designation of Origin (PDO) is a Certified Quality System (CQS) that guarantees that there is a link between the particular characteristics of the production process of certain foodstuffs and their geographical origin. However, there is room for manoeuvre with regard to the management practices implemented when it comes to PDO. This paper investigates the factors related to and explaining the adoption of PDO in the Andalusian olive industry, the main olive growing region in the world, including an analysis of the varying characteristics of mill enterprises, managerial and supervisory staff, and of the differences and similarities between the practices implemented by PDO enterprises compared with the rest. A structured personal interview was held with the managerial and supervisory staff of 101 olive mill enterprises in the main olive growing provinces of Andalusia. The results show that CQS are not in general very widespread but that PDO is relatively prevalent. However no clear adoption factors for PDO have been identified, since the structural characteristics of enterprises adopting PDO and the personal characteristics, attitudes and opinions of their managers and supervisory staff are very similar to those not adopting it. The adoption of PDO seems to be explained by a contagion effect among industries that are located within less favourable, steeply sloping areas. Moreover, the adoption of PDO is not generally linked to an implementation of better industrial practices, rather of better marketing practices, since in general optimal industrial practices are already widespread in Andalusian olive mills. The policy and management implications of enhancing economic viability by increasing the spread of PDO, and by improving the practices implemented by PDO enterprises, are also discussed.
Homotopy and critical morphological sampling

In pattern recognition tasks, it is often convenient to alter the sampling rate of the signal, either to convert to a more appropriate scale/resolution, or to produce an image pyramid and perform the task in an multiresolution fashion. In many of these applications, the mse criteria optimized by the Shannon Sampling Theorem is not appropriate, and other sampling strategies should be considered. In this paper we present a new Critical Sampling Theorem, and extends the results to the case where the connection between several parts of the signal (i.e., the homotopy of the set) is of primary interest. The results are presented for binary signals in an hexagonal grid. Extension for square grids with some specific cases of connectivity criteria is also presented. The results show that it is possible to preserve homotopy while using a sampling density 3 to 4 times smaller than required by previous results. This can be used to reduce the sample density or to improve the detail preservation, and has the potential of improving many multiresolution techniques.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Fusion rule estimation using vector space methods

In a system of N sensors, the sensor S{sub j}, j = 1, 2 .... N, outputs Y{sup (j)} {element_of} {Re}, according to an unknown probability distribution P{sub (Y(j) /X)}, corresponding to input X {element_of} [0, 1]. A training n-sample (X{sub 1}, Y{sub 1}), (X{sub 2}, Y{sub 2}), ..., (X{sub n}, Y{sub n}) is given where Y{sub i} = (Y{sub i}{sup (1)}, Y{sub i}{sup (2)}, . . . , Y{sub i}{sup N}) such that Y{sub i}{sup (j)} is the output of S{sub j} in response to input X{sub i}. The problem is to estimate a fusion rule f : {Re}{sup N} {r_arrow} [0, 1], based on the sample, such that the expected square error is minimized over a family of functions Y that constitute a vector space. The function f* that minimizes the expected error cannot be computed since the underlying densities are unknown, and only an approximation f to f* is feasible. We estimate the sample size sufficient to ensure that f provides a close approximation to f* with a high probability. The advantages of vector space methods are two-fold: (a) the sample size estimate is a simple function of the dimensionality of F, and (b) the estimate f can be easily computed by well-known least square methods in polynomial time. The results are applicable to the classical potential function methods and also (to a recently proposed) special class of sigmoidal feedforward neural networks.
A new unity plan proposal

Although there is general agreement among engineers on the need for unification and a number of plans have been proposed, as yet no one of these has received the full support of the profession. The Unity Organization outlined in this article is suggested by the Pittsfield General Electric Engineers Association as a possible solution.
Woodpile photonic crystal nanocavity in GaAs

High-precision three-dimensional woodpile photonic crystal nanocavities with 40 × 55 × 2.25 unit cells are fabricated in GaAs wafer for 1.55 µm wavelength with the two-directional etching method in a simple two-patterning process.
Zinc adsorption by lime‐treated montmorillonite clay

Abstract In this research, lime‐treated montmorillonite clay is used to adsorb Zn(II) in a wide range of Zn(II) concentrations. Batch test results show that the adsorption of Zn(II) by montmorillonite appears to be dominated by different adsorption mechanisms. At low Zn(II) concentrations, chemisorption affects the amount of Zn(II) adsorbed by montmorillonite. When lime is added, physisorption becomes increasingly important. At high Zn(II) concentrations, physisorption is the dominant mechanism for Zn(II) adsorption. Lime also enhances the ability of montmorillonite to adsorb Zn(II) at low initial Zn(II) concentrations, and does not significantly affect the ability of montmorillonite to adsorb Zn(II) at high initial Zn(II) concentrations. In chemisorption, montmorillonite provides cation exchange sites for the adsorption of Zn(II). In physisorption, montmorillonite acts as not only nucleation center to adsorb zinc hydroxide‐oxides but also helps to coagulate the zinc hydroxide‐oxides. Lime‐treated clay ca...
Wide Ecological Amplitude of a Diversity-Reducing Invasive Grass

The goals of this study were to identify habitats occupied by the Eurasian grass Bothrio- chloa ischaemum (King Ranch bluestem) on the eastern Edwards Plateau of central Texas, USA, and to measure the effects of this invasive species on plant diversity. A set of descriptive field studies were conducted to determine the rela- tionships between habitat characteristics (woody cover, slope, presence of roads and trails, history of prescribed burning, and presence of grazing) and the presence and abundance of this species. Species richness and diversity of perennial her- baceous species were compared between plots in which B. ischaemum was absent and plots that it dominated.The only habitat in which B. ischae- mum was never found was under the canopies of woody plants. B. ischaemum grew in plots of all inclinations (flat sites to steep hillsides), with little evidence of habitat preference. B. ischaemum was more often, although not exclusively, found in plots near roads, probably because roads facilitate seed dispersal. There was no significant relation- ship between either grazing or fire history and the distribution of this species. B. ischaemum- dominated plots had lower species diversity and species richness than plots in which no B. ischaemum was found. The results of this study confirm that B. ischaemum is very common on the eastern Edwards Plateau and suggest that it will continue to spread throughout this region and to reduce native herbaceous plant diversity there.
Inference for spatial processes using subsampling : A simulation study

Many environmental studies involve the measurement of ecological indices that yield spatially dependent data. One quantity that captures the empirical distribution of ecological measurements is the spatial cumulative distribution function (SCDF). Methods for making inferential statements about SCDFs have only recently been developed, one being that of spatial subsampling. While spatial subsampling produces inferential quantities with known asymptotic properties, the performance of this methodology in a finite-sample setting has not previously been investigated. In this article, we review the subsampling method and its theoretical justification, and investigate the performance of this method for finite samples with a simulation study involving several subsampling designs and types of spatial dependence. The subsampling methodology appears to give quite good results over a range of realistic spatial processes. For application to a set of spatially dependent data, an appropriate subsampling procedure may be designed on the basis of quantities contained in the (estimated) variogram.
Enhanced ferrite nanoparticles as MRI contrast agents

Abstract Enhanced ferrite nanoparticles are a new class of contrast agents for magnetic resonance imaging (MRI). The enhanced ferrites are synthesized by reverse micelles technique to form iron core and oxide or ferrite shell preventing further oxidation of the nanoparticles. The nanoparticles are further functionalized using dopamine and PEG-600 to increase the solubility of the high magnetic moment nanoparticles. 1 H relaxation measurements of aqueous solutions of the nanoparticles were conducted at 2.4 T. The relaxivities r 1 and r 2 , representing the slopes of these curves, are 7.19 and 9.96 s −1 mM −1 , respectively. These values should be compared with relaxivities of 4–5 s −1 mM −1 corresponding to commonly used commercial contrast agents in human MR examinations.
Modeling residential development in California from 2000 to 2050: Integrating wildfire risk, wildland and agricultural encroachment

Between 1940 and 2000, nearly 10 million housing units were constructed throughout California. This increased interaction between human and natural communities creates a number of significant socio-ecological challenges. Here we present a novel spatially explicit model that allows better characterization of the extent and intensity of future housing settlements using three development scenarios between 2000 and 2050. We estimate that California's exurban land classes will replace nearly 12 million acres of wild and agricultural lands. This will increase threats to ecosystems and those presented by wildfire, as the number of houses in ‘very high’ wildfire severity zones increases by nearly 1 million.
Improving teacher education, some directions

The central challenge to teacher education today is the establishment of an appropriate balance among the institutional forces which impinge upon it-schools, the practicing profession, and higher education. Without clarification of the roles appropriate to each and without effecting a balance among them which reflects their unique potential contributions, the future of teacher education is bleak. Teacher education, while dependent upon schools, colleges, and the profession, is not the principal business of anybody. The major segment of preservice teacher education continues to be provided within colleges and universities. Yet the responsibility has seldom been accepted with the kind of emphasis and enthusiasm that suggests that the institutions view teacher preparation as an important responsibility. "Although the financial survival of many small colleges is dependent upon their programs and enrollments in teacher education, budget allocations seldom reflect this, and priorities for staff and facilities point elsewhere."' James C. Stone has referred to teacher education as a "stepchild," unwanted by the colleges,2 and an increasing number of educators concerned with this neglect have urged a return of teacher education to the public schools, a plan reminiscent of the city teachers colleges
Simulating flash heating in a muffle tube furnace

— Very rapid heating is an important chondrule-formation process, and it has not been clear whether conventional equipment, such as a muffle tube furnace, is adequate for the simulation of heating on a timescale of seconds. We present a method for measuring the internal temperature reached by a charge during rapid heating when the thermocouple response lags. We have constrained charge temperatures by monitoring the time required to melt metal wires of various compositions and melting points placed inside charges with furnace temperature at 1400, 1500, and 1600 °C. The times required for melting of the metal wires define the temperature paths inside the charges. At 1400 °C, a charge takes 31 s to reach 1399 °C; at 1500 °C, a charge takes 10 s to reach 1495 °C; and at 1600 °C, a charge takes 6 s to reach 1538 °C. Heating rates in vertical muffle tube furnaces are adequate for studying flash melting processes (i.e., of «1 min duration) invoked, for example, in the formation of chondrules.
A nonlinear heat transfer problem: solution of nonlinear, weakly singular Volterra integral equations of the second kind

This paper revisits a classical nonlinear heat transfer problem using modern computational methods based on an equivalent integral formulation. Heat conduction in a semi-infinite medium having a nonlinear boundary condition is considered. This paper investigates the use of two numerical methods for solving the resulting nonlinear, singular Volterra integral equation of the second kind. The Volterra integral equation considered in this paper has a weakly singular kernel of the form k(t,t0) = (t−t0)−x where 0 < x < 1. Integral equations having this type of kernel appear in many facets of engineering and physics. The present paper investigates the global and local use of singularity subtraction and product integration. These methods effectively overcome the numerical difficulties associated with weakly singular kernels of this type. Next, a numerical procedure based on trapezoidal integration and a Newton-Raphson method is shown to produce accurate results rapidly.
Four-quark condensates at T≠0

Abstract Temperature dependence of four-quark condensates is calculated in the soft pion approach. Factorization hypothesis is shown to be invalid at T≠0.
Refinement of the crystal structure of the solid electrolyte α (Cs0.55Rb0.45)Cu4Cl3(I1.9Cl0.1)

Abstract The crystal structure of metastable α(Cs0.55Rb0.45)Cu4Cl3(I1.9Cl0.1) at room temperature has been refined from single crystal X-ray diffraction data. The crystal on which the structure analysis was done belongs to space group P4132, isostructural with RbAg4I5, and has a lattice constant of 10.100 ± 0.003 A. As predicted, the substitution of Cs+ for Rb+ does not have a significant effect on the conduction passageways in the α phase.
Aberrant LPL Expression, Driven by STAT3, Mediates Free Fatty Acid Metabolism in CLL Cells

While reviewing chronic lymphocytic leukemia (CLL) bone marrow slides, we identified cytoplasmic lipid vacuoles in CLL cells but not in normal B cells. Because lipoprotein lipase (LPL), which catalyzes hydrolysis of triglycerides into free fatty acids (FFA), is aberrantly expressed in CLL, we investigated whether LPL regulates the oxidative metabolic capacity of CLL cells. We found that unlike normal B cells, CLL cells metabolize FFAs. Because STAT3 is constitutively activated in CLL cells and because we identified putative STAT3 binding sites in the LPL promoter, we sought to determine whether STAT3 drives the aberrant expression of LPL. Transfection of luciferase reporter gene constructs driven by LPL promoter fragments into MM1 cells revealed that STAT3 activates the LPL promoter. In addition, chromatin immunoprecipitation confirmed that STAT3 binds to the LPL promoter. Furthermore, transfection of CLL cells with STAT3-shRNA downregulated LPL transcripts and protein levels, confirming that STAT3 activates the LPL gene. Finally, transfection of CLL cells with LPL-siRNAs decreased the capacity of CLL cells to oxidize FFAs and reduced cell viability. Implications: Our study suggests that CLL cells adopt their metabolism to oxidize FFA. Activated STAT3 induces LPL, which catalyzes the hydrolysis of triglycerides into FFA. Therefore, inhibition of STAT3 is likely to prevent the capacity of CLL cells to utilize FFA. Mol Cancer Res; 13(5); 944–53. ©2015 AACR .
Optimality principles in sensorimotor control

The sensorimotor system is a product of evolution, development, learning and adaptation-which work on different time scales to improve behavioral performance. Consequently, many theories of motor function are based on 'optimal performance': they quantify task goals as cost functions, and apply the sophisticated tools of optimal control theory to obtain detailed behavioral predictions. The resulting models, although not without limitations, have explained more empirical phenomena than any other class. Traditional emphasis has been on optimizing desired movement trajectories while ignoring sensory feedback. Recent work has redefined optimality in terms of feedback control laws, and focused on the mechanisms that generate behavior online. This approach has allowed researchers to fit previously unrelated concepts and observations into what may become a unified theoretical framework for interpreting motor function. At the heart of the framework is the relationship between high-level goals, and the real-time sensorimotor control strategies most suitable for accomplishing those goals.
THE FREQUENCY OF OCCURRENCE OF DUST EXPLOSIONS

ABSTRACT A constitutive model to predict the frequency of occurrence of a dust explosion in a specified system is presented. This model has been adopted to examine the effect of dust concentration on the frequency of occurrence of dust explosions. The model incorporates one fitting constant as well as the activation energy of the dust used. Explosion experiments were carried out to establish the effect of dust concentration on the frequency of occurrence of explosions. One hundred explosion tests were carried out for each concentration, under the same set of conditions. The validity of the proposed model is demonstrated in view of the experimental data.
Clinical evaluation of liquid placebos for an herbal supplement, STW5, in healthy volunteers

Summary Background Although clinical trials are needed to evaluate the efficacy of liquid herbal medicinal products, design of feasible placebos that mimic the appearance, taste, and smell of such products is particularly challenging. Objective The design and feasibility of a liquid placebo for STW5, an herbal medicinal product used for various gastrointestinal problems, was explored in this study. Design Four sample products—STW5, a fresh and aged version of a placebo made from a seasoning mix (Maggi™), and a placebo with aged artificial flavor and food coloring—were compared in two organoleptic (sensory), single-blind trials with a total of 60 ( N =60) healthy volunteers ( n 1 =30, n 2 =30). Measurements The appearance, smell, and taste of each solution were evaluated using a Likert scale questionnaire. Results The liquid placebos evaluated were similar in regard to appearance, smell, and taste. However, participants indicated that for a clinical trial with STW5, the aged Maggi™ placebo would be more viable compared to the fresh Maggi placebo or the aged artificial food coloring placebo with licorice flavor. Participants also noted that the mint flavor and smell of STW5 was distinctly different from the placebo solutions. Limitations The trials were conducted in healthy volunteers, not in actual patients. Conclusions The aged Maggi™ liquid mix may be more favorable as a placebo than the artificially created one. However, further adjustment will need to be made to the Maggi™ placebo to simulate the complex aromatic composition of STW5 for clinical studies in the future.
Mutagenesis of a Proton Linkage Pathway in Escherichia coli Manganese Superoxide Dismutase

Mutagenesis of Escherichia coli manganese superoxide dismutase (MnSD) demonstrates involvement of the strictly conserved gateway tyrosine (Y34) in exogenous ligand interactions. Conservative replacement of this residue by phenylalanine (Y34F) affects the pH sensitivity of the active-site metal ion and perturbs ligand binding, stabilizing a temperature-independent six-coordinate azide complex. Mutant complexes characterized by optical and electron paramagnetic resonance (EPR) spectroscopy are distinct from the corresponding wild-type forms and the anion affinities are altered, consistent with modified basicity of the metal ligands. However, dismutase activity is only slightly reduced by mutagenesis, implying that tyrosine-34 is not essential for catalysis and may function indirectly as a proton donor for turnover, coupled to a protonation cycle of the metal ligands. In vivo substitution of Fe for Mn in the MnSD wild-type and mutant proteins leads to increased affinity for azide and altered active-site properties, shifting the pH-dependent transition of the active site from 9.7 (Mn) to 6.4 (Fe) for wt enzyme. This pH-coupled transition shifts once more to a higher effective pKa for Y34F Fe2-MnSD, allowing the mutant to be catalytically active well into the physiological pH range and decreasing the metal selectivity of the enzyme. Peroxide sensitivities of the Fe complexes are distinct for the wild-type and mutant proteins, indicating a role for Y34 in peroxide interactions. These results provide evidence for a conserved peroxide-protonation linkage pathway in superoxide dismutases, analogous to the proton relay chains of peroxidases, and suggests that the selectivity of Mn and Fe superoxide dismutases is determined by proton coupling with metal ligands.
Melting of an ice surface in porous medium

The buoyancy-driven flow of cold water is seriously affected by the existence of a density extremum in the vicinity of 4°C at atmospheric pressure. In this study we examine the effect of such flow on the melting of a flat ice surface inside a porous matrix. Two basic configurations are considered: a vertical flat surface and a horizontal flat surface. Interesting results document the flowfield in the liquid region. For the vertical plate configuration, depending on the water temperature far from the surface, this flow may be directed upward or downward. A regime that features local flow reversals was also identified. The effect of the flow in the melt region on the melting phenomenon (melting rate and local heat transfer) was also studied. It was found that both the flow reversals and the melting phenomenon itself reduce the local heat transfer at the melting surface. /
Ten-year analysis of the Björk-Shiley standard aortic valve.

Abstract Long-term performance characteristics of the Bjork-Shiley standard aortic valve were determined by analyzing the follow-up of 514 patients undergoing operation between 1971 and 1981. Cumulative follow-up was 2,601 patient-years (average, 5.3 ± 3.8 years); 53% (238/452) of hospital survivors have been followed more than 5 years. Valve-related complications expressed as both actuarial event-free percents (± standard error at 10 years) and first-event linearized determinations (percent per patient-year) occurred at the following rates: thromboembolism, 82 ± 3 and 2.3 ± 0.3, respectively; anticoagulant-related hemorrhage, 60 ± 4 and 5.6 ± 0.5; prosthetic valve endocarditis, 94 ± 2 and 0.8 ± 0.2; valve thrombosis, 97 ± 1 and 0.4 ± 0.1; reoperation, 94 ± 2 and 0.6 ± 0.2; valve failure, 82 ± 4 and 1.6 ± 0.2; and composite valve-related morbidity and mortality, 46 ± 4 and 8.8 ± 0.2. Overall survival was 72 ± 2% at 5 years and 55 ± 3% at 10 years; valve-related complications accounted for 22% of the late deaths. Although no instance of structural valve failure could be identified, 25% of valve-related complications resulted from valve failure, of which 67% were fatal. By 10 years, 54% of patients had experienced at least one form of major valve-related complication, 16% of which proved fatal. The Bjork-Shiley standard aortic valve has late valve-related complications similar to other existing mechanical prostheses that have been subjected to long-term analysis.
Neurotensin protects pancreatic beta cells from serum deprivation.

In a recent article entitled “Neurotensin protects pancreatic beta cells from apoptosis” Coppola et al. (2008) show that neurotensin (NT) protects insulin-producing cells (β-TC3, INS-1E) against IL...
Modeling geminate pair dissociation in organic solar cells: high power conversion efficiencies achieved with moderate optical bandgaps

We propose a model for geminate electron–hole dissociation in organic photovoltaic (OPV) cells and show how power conversion efficiencies greater than those currently achieved might be realized via design strategies employing moderate optical bandgaps and enhanced charge delocalization near the donor–acceptor interface. Applying this model to describing geminate electron–hole dissociation via charge transfer (CT) states, we find good agreement with recently published high-efficiency experimental data. The optimal bandgap for current-generation organic active layer materials is argued to be ∼1.7 eV – significantly greater than in previous analyses, including the Shockley–Queisser approach based upon non-excitonic solar cell dynamics. For future higher efficiency OPVs, the present results show that the optimal bandgap should be slightly lower, ∼1.6 eV. Finally, these results support design strategies aimed at enhancing mobility near the donor–acceptor interface and reducing the electron–hole binding energy, rather than striving to further reduce the bandgap.
Empirical strengths of spin operators in nuclei

Abstract New shell-model wave functions, derived from a single parametrization of the effective Hamiltonian, have been calculated for all sd-shell nuclei. The energies and matrix elements for single-nucleon transfer and electric-multipole operators predicted from these calculations are briefly surveyed in comparison with experimental values. The matrix elements predicted from these wave functions for Gamow-Teller, magnetic-dipole and other related spin-type operators are then compared in detail with the magnitudes of the corresponding experimentally determined matrix elements from A = 17–39 nuclei. From these comparisons, the empirical corrections to the free-nucleon normalizations of these spin operators are extracted. These empirical values of the corrections are compared with theoretical estimates of the effects of many-ω-configuration mixing and of mesonic-exchange currents and isobar excitations. Finally, the predicted distributions of matrix-element magnitudes with excitation energy are studied and compared with experiment, the difference between Gamow-Teller and M1 probes examined and the predicted momentum-transfer-dependence of the matrix elements compared with the results of electron scattering experiments.
Distinct folding pathways of two homologous disulfide proteins: bovine pancreatic trypsin inhibitor and tick anticoagulant peptide.

Abstract The folding pathways of disulfide proteins vary substantially (Arolas et al., Trends Biochem Sci 31: 292–301, 2006). The diversity is mainly manifested by (a) the extent of heterogeneity of folding intermediates, (b) the extent of presence of native-like intermediates, and (c) the variation of folding kinetics. Even among structurally similar proteins, the difference can be enormous. This is demonstrated in this concise review with two structurally homologous kunitz-type protease inhibitors, bovine pancreatic trypsin inhibitor and tick anticoagulant peptide, as well as a group of cystine knot proteins. The diversity of their folding mechanisms is illustrated with two different folding techniques: (a) the conventional method of disulfide oxidation (oxidative folding), and (b) the novel method of disulfide scrambling (Chang, J Biol Chem 277: 120–126, 2002). This review also highlights the convergence of folding models concluded form the conventional conformational folding and those obtained by oxid...
SU-GG-T-430: Normalized Bragg Peak Curves for Various Proton Energies in a Cylindrical Water Phantom: A Simulation with MCNPX and GEANT4 Monte Carlo Codes

Purpose: To simulate protoninteraction(energy from 60 to 250 MeV) in water using MCNPX version 2.7B Monte Carlo code to determine accurately proton ranges from Bragg peak. Method and Materials: A cylindrical water phantom (100cm length, 30cm radius), composed of 1000 packed circular sensitive detector discs (2cm radius, 1 mm thick) was used. A pencil beam source was incident on the surface of the cylinder in z direction. Tabular nuclear data from LA150N and LA150H libraries were used for neutrons and protons with 150 MeV, the LAHET physics code was used and the hadronic interactions were handled using the Bertini cascade model. The Vavilov model was used to account for charged‐particle straggling. Normal transport was performed for neutron,proton,photon, electron, deuteron, triton, helium‐3, alpha, and heavy ions. Light ion recoil was accounted for in the simulations and the cutoff energy for these particles was set to zero to prevent early termination of their transport. A 5cm × 5cm field size beam was also simulated. A total of 80,000 source histories were run for each simulation. Eleven sourceenergies were tested for the pencil beam and three sourceenergies were studied for the 5cm × 5cm field size beam. Results: Our MCNPX results were compared with GEANT4 results as well as the Continuing Slowing Down Approximation (CSDA) data from the United States National Institute of Standards and Technologies (NIST). The deviation in Bragg peak range was <1% of that calculated with the GEANT4 and <0.6% of the CSDA data. The entrance to peak dose ratios between the different codes were comparable for 150 and 200 MeV though larger difference was noted for 250 MeV beam. Conclusions: Our proton Bragg peak simulation results using MCNPX are in excellent agreement with GEANT4 as well as NIST data.
The Decline and Fall of Deregulation

Hopes for a price-competitive, deregulated health economy are fading as the end of Ronald Reagan's second term approaches. The current output of professional health care journals includes a declini...
PHOSPHATE (Pi) UPTAKE IN FETAL LAMB (FL) RENAL BRUSH BORDER MEMBRANES (BBMV)

We investigated Pi uptake (PiU) in BBMV in 9 FL and 6 ewes (E) at 100-165 days' gestation. BBMV were prepared by differential centrifugation, and PiU was measured by Millipore filtration. PiU after lh incubation in extravesicular media (EM) with [sucrose] from 0.3-1.0 osm varied inversely with [1/osm] (r-0.94, p [Na+]i); 2-Na+-dependent [(Na+-G)-(O-Na+)]. In FL, Na+-G PiU varied directly with EM pH from 6.5-8.5 (r-.79, p<.01) and was 1.6-fold greater at pH 6.5 than at pH 8.5. Na+-G PiU at 15s in FL remained linear with EM [substrate] 0.1-3.0 mMol (r-.99, p<.001); however, O-Na+ PiU was saturated at 0.8 mMol with an apparent Km of 0.39 mMol and Vmax of 48.4 nMol/15s·mg protein. The results suggest significant differences between mechanisms of renal Pi handling in FL compared to E with non-Na+-Dep active PiU also present in FL. This may explain in part low renal Pi excretion in early life.
Determination of δ-aminolevulinate dehydratase activity by a specific fluorometric coupled-enzyme assay

Abstract A coupled-enzyme assay for the specific and sensitive determination of δ-aminolevulinate dehydratase activity has been developed. The assay specifically measured picomole quantities of the product, porphobilinogen, by its enzymatic conversion to uroporphyrinogen I and the fluorometric detection of oxidized uroporphyrin I. The coupled-enzyme assay was linear with time and protein concentration and required less than 3 h for 20 individual determinations. Under the standard assay conditions, 10 to 100 pmol of uroporphyrin I was reliably measured, representing 0.085 to 0.850 nmol/h of δ-aminolevulinate dehydratase activity per assay. In addition, the fluorometric assay was more sensitive than either the standard or the semimicro colorimetric methods. The specificity, rapidity, and sensitivity of this new fluorometric method facilitates the reliable determination of low levels of aminolevulinate dehydratase activity in small amounts of crude tissue homogenates or in cultured cells.
Influence of Extrinsic Plantar Flexors on Forefoot Loading During Heel Rise

This investigation studied the effects of simulated plantar flexor muscle activity on forefoot loading using a static cadaver model. Nine cadaver feet were mounted in an apparatus in the heel rise position. Using computer-controlled and pneumatic actuators, forces were simultaneously applied to the tendons of the triceps surae, flexor hallucis longus, flexor digitorum longus, peroneus brevis and longus, and tibialis posterior until 750 N of ground reaction force was achieved, at which time forefoot plantar pressure patterns were captured immediately with a pedobarograph. Second metatarsal bending moments were calculated from strain gauge data collected concurrently. Consecutive loading cycles were performed with sequential elimination of simulated muscle force from each tendon except the Achilles. Loss of simulated flexor hallucis longus activity significantly decreased great toe contact forces and significantly increased forces under the forefoot. Simulated loss of both the flexor hallucis longus and flexor digitorum longus caused significant decreases in contact area, pressure, and force beneath the toes and significant increases in contact area and force under the forefoot. Bending moments in the second metatarsal were shown to vary directly with peak pressure under the second metatarsal head (r = 0.801). These findings demonstrate the load distributing function of the extrinsic plantar flexors during heel rise.
3β-Hydroxysteroid dehydrogenase/Δ5→4-isomerase expression in rat and characterization of the testis isoform

Abstract The isolation, cloning and expression of a DNA insert complementary to mRNA encoding rat testis 3β-hydroxysteroid dehydrogenase/Δ5→4-isomerase (3β-HSD) is reported. The insert contains an open reading frame encoding a protein of 373 amino acids, which exhibits 73% and 78% identity to the cDNA encoding the human placental form at the amino acid and nucleotide levels respectively. Northern blot analysis of total RNA of rat tissues using as probe a specific radiolabeled cDNA insert encoding rat testis 3β-HSD demonstrated high levels of 1.6 kb mRNA species in ovary, adrenal and Leydig tumor, with lower but detectable message in testis and adult male liver, while the probe also hybridized to a 2.1 kb mRNA species in liver. The cDNA was inserted into a modified pCMV vector and expressed in COS-1 monkey kidney tumor cells. The expressed protein was similar in size to 3β-HSD present in H540 Leydig tumor cell homogenate and human placental microsomal 3β-HSD, as detected by immunoblot analysis, and catalyzed the conversion of pregnenolone to progesterone, 17α-hydroxypregnenolone to 17α-hydroxyprogesterone, and dehydroepiandrosterone to androstenedione. Transfected COS cell homogenates, supplemented with NAD+, but not NADP+, converted pregnenolone to progesterone and dehydroepiandrosterone to androstenedione with apparent Km values of 0.13 and 0.09 μM, respectively. Immunoblot analysis of various rat tissues using a polyclonal antibody directed against human placental 3β-HSD, in addition to immunoreactivity in the adrenal and testis, demonstrated immunoreactive 3β-HSD protein in adult male liver, but not in adult female or fetal liver. We conclude that while one gene product is highly expressed in testicular Leydig cells, and probably adrenal and ovary, accounting for their 3β-HSD content, a 3β-HSD is also expressed in liver in a sex-specific manner.
Effects of gonadal hormones on pacing of sexual contacts by female rats

The role of exogenous hormones in mediating pacing of reproductive encounters by ovariectomized female rats was investigated. Five estradiol benzoate (EB) treatment groups (3.3, 10, 30, 60, or 90 μg/kg) were each given five weekly tests in a two-compartment escape-reentry mating arena in the presence of three sexually vigorous males. Prior to testing, each subject received one of four dosages of progesterone (P) (1, 2, 4, or 8 mg/kg) or oil. The mean time subjects spent in the escape compartment following an intromission or ejaculation decreased for all EB treatment groups as P levels increased. The percentage of intromissions followed by retreats to the escape compartment decreased similarly for all EB treatment groups as P increased. Lordosis response increased as a function of increasing levels of EB alone or in combination with increasing levels of P.
Effects of Computer Use on High School Students' Sense of Community

ABSTRACT The author used a mixed-method design to determine whether and how use of computers in the classroom affects sense of learning in a community among high school students (N = 181). The results indicate that using computers in the classroom positively affects students' sense of learning in a community. Analyses revealed that students believed that connectedness with their peers is the most important variable in developing a sense of community. Results suggest the following policy implications for urban education: (a) use of computers in teaching may add to the sense of classroom community and (b) sense of community is important and may be linked to academic success.
A comparison of usage data among types of aircraft

It has long been an accepted proposition that base level usage df technical repair items for aircraft is related to program elements. The program element most often cited in this connection is flying hours. Evidence of this relationship on a line item basis, however, has been sparse. This study suggests that although the supposed relation is intuitively plausible, for most line items it cannot be effectively utilized in projecting base level requirements. The basis of this conclusion is an analysis of demand characteristics for technical repair items for a variety of naval aircraft.
An evolutionary analysis of psychological pain following rape. III: Effects of force and violence

Mental pain has been hypothesized to reflect psychological adaptation designed by selection to detect and cope with the occurrence of social problems that reduced individuals inclusive fitness in human evolutionary history. According to the hypothesis, mental pain is brought about by social tragedies in the lives of individuals and focuses an individual's attention on the events surrounding the pain, promoting correction of the pain-causing events and their avoidance in the future. The hypothesis applied to rape victims argues that in human evolutionary history raped females had increased fitness as a result of mental pain, because the pain forced them to focus their attention on the fitness-reducing circumstances surrounding rape, which are discussed. Some of the hypothesis' predictions about the psychological pain of rape victims are examined using a data set of 790 rape victims who were interviewed about their psychological traumatization within five days after the assault. Earlier analyses of these data have indicated that, as predicted, both a victim's age and marital status are proximate causes of the magnitude of psychological pain following rape: Reproductive-aged women appear to have been more severely traumatized by rape than older women or girls and married women more than unmarried women. The analyses herein indicate that, as predicted, reproductive-aged women are more likely to be victims of force and/or violence during rape than are older women or young girls. When force and/or violence was controlled, reproductive-aged women were still more psychologically traumatized by rape than were either older women or young girls. The results suggest that the psychology that regulates mental pain processes information about age and mateship status in the event of a woman's rape. The analyses reported here indicate that stranger rapes are more forceful and violent than either friend or family-member rapes.
Dynamic light scattering investigations of RecA self-assembly and interactions with single strand DNA.

Abstract Dynamic light scattering (DLS) measurements were performed on self-assembled solutions of RecA as a function of assembly time under strand exchange ionic strength conditions (10 mM MgCl 2 , 65 mM NaCl, 10 mM Tris-HCl, pH = 7.5, 1 mM DTT, 3–4 μM RecA) in the absence of ATP. These measurements yield distributions of the translational diffusion coefficients of the changing populatios of assembling protein species. Interpretations of results of DLS measurements are made in terms of model hydrodynamic calculations that indicate, under the solution conditions employed, the smallest fundamental quaternary subunit of RecA is a hexamer in a toroidal or lock-washer configuration. Interactions of M13mp19 circular single strand DNA (ssDNA) with RecA assembled to different stages were also investigated. Additions of ssDNA to self-assembled solutions of RecA acts to dissociate the associated structures into hexamer subunits. However, the effect of ssDNA on assembled RecA is highly dependent on the RecA self-assembly state. The longer the assembly time, the less reversible the self-assembled structures of RecA become. Binding isotherms of titrated mixtures of ssDNA with RecA self-assembled to various stages were also determined. Evaluated dissociation constants of RecA/ssDNA complexes were found to increase with increases of the associated state of RecA. These results strongly suggest that, under the solvent conditions employed, the active ssDNA binding form of RecA is a hexamer.
Stationary and nonstationary correlation-frequency analysis of heterodyne mode laser light scattering: magnitude and periodicity of canine tracheal ciliary beat frequency in vivo

Stationary and nonstationary correlation-frequency analysis of heterodyne laser light scattering were utilized to make automated, on-line, objective measurements of tracheal ciliary beat frequency (CBF) in intact, anesthetized canines. The stationary correlation-frequency analysis laser light-scattering technique was used to assess the magnitude of the CBF stimulatory responses induced by aerosolized 10(-5) M fenoterol (sympathomimetic), and 10(-8) M and 10(-6) M methacholine (parasympathomimetic) delivered to the whole lungs of eight barbiturate-anesthetized beagles. The nonstationary correlation-frequency analysis laser light-scattering technique was used to measure the effect on tracheal CBF of increasing the cytosolic calcium ion concentration with a calcium ionophore, A23187. Aerosolized A23187 was delivered to the isolated tracheal lumens of eight beagle dogs in cumulative doses ranging from 10(-9)M to 10(-6) M. Administration of the ionophore synchronized the CBF with a period of 5.3min. Dose dependencies were observed in both the time to the peak CBF stimulation and the magnitude of the stimulatory response. The magnitude of CBF stimulation was inhibited by prior administration of aerosolized nifedipine (2 mg/ml), a voltage-operated calcium channel blocker. The A23187-induced modulation period of tracheal CBF, was unchanged by nifedipine. These are the first data to demonstrate that the magnitude and periodicity of CBF are two independent coupled processes. The cooperativity of these two processes could be determined in the effectiveness of mucociliary transport.
Composition of clay-fraction organic matter in Holocene paleosols revealed by advanced solid-state NMR spectroscopy

Abstract Identifying which components of organic matter are preserved over millennia in paleosols is important for understanding the stabilization mechanisms of soil organic matter (SOM) and in evaluating the portion of the terrestrial carbon stock that might be attributed to paleosols. Using advanced solid-state nuclear magnetic resonance (NMR) techniques, we examined the chemical composition of clay-associated SOM in a chronosequence of four paleosols and one modern soil collected from a site in the eastern Great Plains in Kansas, USA. The NMR spectra of clay SOM of the paleosols indicated the presence of OCH and CH 2 moieties, which represent polysaccharides and lipids, respectively. The paleosol SOM also showed an appreciable peptide component, as indicated by signals of NCH and N C O. As in the modern soil, lignin residues in the paleosols contributed little to the SOM, and condensed aromatics contributed modestly to the clay SOM. The Roberts Creek paleosol samples were exceptions. Their NMR spectra included a considerable nonprotonated aromatic carbon component, reflecting fused aromatic rings and suggesting the presence of clay-fraction charcoal residues, probably originating from paleofires. In the clay SOM of both the paleosols and the modern soil, the polysaccharides and peptides indicated by the NMR spectra are consistent with the presence of microbially derived peptidoglycan and perhaps chitin residues. We conclude that lipids, charcoal, and polysaccharides, probably in the form of microbial residues, are likely to be the dominant SOM components in the paleosol clay fractions.