cssi/SciSciGPT-SciSciNet huggingface dataset:
Regulation of testosterone hydroxylation by rat liver microsomal cytochrome P-450.

The pathways of testosterone oxidation catalyzed by purified and membrane-bound forms of rat liver microsomal cytochrome P-450 were examined with an HPLC system capable of resolving 14 potential hydroxylated metabolites of testosterone and androstenedione. Seven pathways of testosterone oxidation, namely the 2α-, 2β-, 6β-, 15β-, 16α-, and 18-hydroxylation of testosterone and 17-oxidation to androstenedione, were sexually differentiated in mature rats (male/female = 7–200 fold) but not in immature rats. Developmental changes in two cytochrome P-450 isozymes largely accounted for this sexual differentiation. The selective expression of cytochrome P-450h in mature male rats largely accounted for the male-specific, postpubertal increase in the rate of testosterone 2α-, 16α-, and 17-oxidation, whereas the selective repression of cytochrome P-450p in female rats accounted for the female-specific, postpubertal decline in testosterone 2β-, 6β-, 15β-, and 18-hydroxylase activity. A variety of cytochrome P-450p inducers, when administered to mature female rats, markedly increased (up to 130-fold) the rate of testosterone 2β-, 6β-, 15β-, and 18-hydroxylation. These four pathways of testosterone hydroxylation were catalyzed by partially purified cytochrome P-450p, and were selectively stimulated when liver microsomes from troleandomycin- or erythromycin estolate-induced rats were treated with potassium ferricyanide, which dissociates the complex between cytochrome P-450p and these macrolide antibiotics. Just as the testosterone 2β-, 6β-, 15β-, and 18-hydroxylase activity reflected the levels of cytochrome P-450p in rat liver microsomes, so testosterone 7α-hydroxylase activity reflected the levels of cytochrome P-450a; 16β-hydroxylase activity the levels of cytochrome P-450b; and 2α-hydroxylase activity the levels of cytochrome P-450h. It is concluded that the regio- and stereoselective hydroxylation of testosterone provides a functional basis to study simultaneously the regulation of several distinct isozymes of rat liver microsomal cytochrome P-450.
STM study of surface reconstructions of Si(111):B.

The scanning tunneling microscope is used to study the boron-doped Si(111) surface as a function of annealing times and temperatures. The surface structure is found to be determined by the concentration of B. When the substitutional B concentration is less than 1% of the top 1[times]1 bilayer atoms, the surface is largely 7[times]7 but surrounded by adatom-covered 1[times]1 regions (which have higher B concentration). When the B concentration is more than 3%, the whole surface will be adatom-covered 1[times]1 regions including ([radical]3 [times] [radical]3 )[ital R]30[degree] structures. The ([radical]3 [times] [radical]3 )[ital R]30[degree] domains will increase with the B concentration. Because 7[times]7 can only exist in the region with low B concentration, the growth of 7[times]7 is slowed down. Further annealing at 560 [degree]C can convert 2[times]2, [ital c](4[times]2) into 7[times]7 and 9[times]9. Sides of the 7[times]7 domain preferentially grow along the three equivalent [11[bar 2]] directions. The adatom-covered 1[times]1 regions are bounded by faulted halves of the 7[times]7 domains. The dark sites of 7[times]7 are observed and counted. They are further interpreted in terms of a B substitution model. The pattern of bright and dark atoms in ([radical]3 [times] [radical]3 )[ital R]30[degree] domains is analyzed and a criterion formore » a B stabilized Si-([radical]3 [times] [radical]3 )[ital R]30[degree] structure is obtained.« less
Regulation of Arabidopsis Early Anther Development by Putative Cell‐Cell Signaling Molecules and Transcriptional Regulators

Anther development in flowering plants involves the formation of several cell types, including the tapetal and pollen mother cells. The use of genetic and molecular tools has led to the identification and characterization of genes that are critical for normal cell division and differentiation in Arabidopsis early anther development. We review here several recent studies on these genes, including the demonstration that the putative receptor protein kinases BAM1 and BAM2 together play essential roles in the control of early cell division and differentiation. In addition, we discuss the hypothesis that BAM1/2 may form a positive-negative feedback regulatory loop with a previously identified key regulator, SPOROCYTELESS (also called NOZZLE), to control the balance between sporogenous and somatic cell types in the anther. Furthermore, we summarize the isolation and functional analysis of the DYSFUNCTIONAL TAPETUM1 (DYT1) gene in promoting proper tapetal cell differentiation. Our finding that DYT1 encodes a putative transcription factor of the bHLH family, as well as relevant expression analyses, strongly supports a model that DYT1 serves as a critical link between upstream factors and downstream target genes that are critical for normal tapetum development and function. These studies, together with other recently published works, indicate that cell-cell communication and transcriptional control are key processes essential for cell fate specification in anther development.
Action of drugs of abuse on brain reward systems: An update with specific attention to opiates

In addressing the role that the substrate of brain stimulation reward might play in drug abuse, Wise [47] reviewed evidence relating brain stimulation and psychomotor stimulant reward to dopaminergic but not noradrenergic elements identified with brain reward circuitry. He then speculated that one possible mechanism of opiate, ethanol, barbiturate or benzodiazepine reward might involve a specified disinhibition of the dopaminergic element. He suggested that these drugs might have inhibitory actions on locus coeruleus, which in turn might send an inhibitory projection to the dopaminergic link in reward circuitry. This speculation is challenged with respect to ethanol in the companion article [1] and with respect to opiates in the present article. Recent evidence indicates that the rewarding action of opiates is mediated in the region of the dopaminergic cells of the ventral tegmentum and not in the region of the noradrenergic cells of locus coeruleus. Rewarding opiate injections appear to activate the same or a similar dopaminergic link in brain reward circuitry as that thought to be activated through its afferent inputs in the case of brain stimulation reward and activated at its synaptic terminals in the case of psychomotor stimulant reward. Whether other drugs of abuse activate links in brain reward circuitry which function in parallel or in series with the dopaminergic link identified with opiates and stimulants remains an open question.
Generation cycle of rat megakaryocytes

Abstract The generation (endoreduplication) cycle of megakaryocytes of rat bone marrow was measured by the method of determining the labeling index of mitotic figures after a single injection of tritiated thymidine. A measure of the relative rates of DNA synthesis per cell during the course of the S driod was also obtained from counts over the labeled mitotic figures. The total generation cycle time was about 9.3 h and synthesis time about 7.6 h. Approximately one-third of the most immature stage of megakaryocytes belongs to the endoreduplicating population. The DNA synthesis rate per cell changed with time, attaining peak activity between the 4th and 5th hour after the beginning of S, and dropping rapidly again to the end of S.
Biosynthesis of Cholesterol in an Insect, Silverfish ( Ctenolepisma sp.)

MUCH nutritional1–4 and biochemical5,6 evidence suggests that the insects, as a phylum, are incapable of synthesizing sterols. This biosynthetic deficiency results, in general, in a dietary requirement of insects for some sterol without which they cannot grow to maturity. The apparent capacity of two species to thrive on a sterol-free diet has been shown to reflect the sterol-synthesizing activity of their intestinal micro-organisms which supply sterols (as well as vitamins of the B group) in quantities sufficient to satisfy the insects' growth requirements7. Similarly, in the cockroach, Blattella germanica, incorporation of dietary [1-14C] acetate into sterol, which occurs under non-aseptic conditions, has been shown to be almost entirely abolished in insects reared aseptically6. It has been shown that the sterol synthesis observed in this insect under non-aseptic conditions is due to initial synthesis of ergosterol by the intestinal flora, followed by the conversion of this compound to 22-dehydrocholesterol in the tissues of the insect. The rate of formation of 22-dehydrocholesterol by this process is, however, not sufficient to render the cockroach independent of a supply of sterol in its food8.
A rapid in vitro assay for carcinogenicity of chemical substances in mammalian cells utilizing an attachment-independence endpoint

Rauscher leukemia virus (RLV)-infected rat embryo cells have been shown to be sensitive to neoplastic transformation by a variety of chemical carcinogens. The mass assay technique normally used requires 6 to 15 weeks before morphologically altered foci of cells are observed. While growth in soft agar is considered to be one of the best in vitromeans for confirming neoplastic transformation, this assay requires 4 additional weeks beyond focus formation. We have devised a rapid new assay for determining carcinogenicity of chemicals. The method takes advantage of the range of chemical sensitivity of RLV-infected rat embryo cells, but provides, in 10 days, for a readout based on the ability of transformed cells to survive under conditions which select for attachment independence. The target cells, 2FR450, were treated for 72 h with chemical and then plated into Petri dishes containing a solid bottom layer of agar/medium. Viable cell counts were made 3 and 6 days later and compared to parallel data from solvent-treated control cells. 2FR450 cells treated with any of 10 chemical carcinogens, including such diverse compounds as benzo(a)pyrene, 3-methylcholanthrene, 2-acetylaminofluorene, NiSO4and urethane, showed an average increase of 225% in survival over controls. Phenanthrene, a non-carcinogen, induced no increase in survival of 2FR450 cells. This assay appears to permit detection of carcinogens of various chemical types with a simple test readout within 10 days.
Out in the Country: Rural Sexual Minority Mothers

Rural and urban sexual minority mothers' parenting experiences related to sexual orientation were compared. Participants were 414 mothers in same-sex relationships with at least one child under the age of 18 years living in their home who was planned with their current partner. Rural mothers were more likely to be biological parents and not adoptive parents. Rural mothers reported higher rates of discrimination from strangers and people in service or helping professions. Although outness for rural and urban mothers did not differ, for children, classmates' parents and neighbors were less likely to know the family's status in rural areas. Rural and urban mothers did not differ on internalized homophobia, social support, or stigma consciousness. Clinical and policy implications are discussed.
Analyzing and Designing Serial Flexure Elements

In this paper we introduce the principles necessary to analyze and design serial flexure elements, which may be used to synthesize advanced compliant mechanisms (CMs). The most commonly used flexure elements (e.g., wire, blade, or living hinge flexures) are often parallel and thus impose constraining forces directly through all parts of their geometry to the rigid bodies that they join within the CM. Serial flexure elements, on the other hand, constrain rigid bodies with a larger variety of forces and moments and thus enable CMs to achieve (i) more degrees of freedom (DOFs), (ii) larger dynamic and elastomechanic versatility, and (iii) greater ranges of motion than parallel elements. In this paper, we extend the principles of the Freedom and Constraint Topologies (FACT) synthesis approach such that it enables the synthesis of CMs that are not only constrained by parallel flexure elements, but also by serial elements. FACT utilizes geometric shapes to intuitively guide designers in visualizing compliant element geometries that achieve any desired set of DOFs. In this way, designers can rapidly generate a host of new serial flexure elements for various CM applications. Such elements are provided here as case studies.Copyright © 2013 by ASME
Accelerated late gadolinium enhancement cardiac MR imaging with isotropic spatial resolution using compressed sensing: initial experience.

Low-dimensional-structure self-learning and thresholding reconstruction accelerates data acquisition in three-dimensional late gadolinium enhancement MR imaging by a factor of three with use of a clinically available five-channel phased-array cardiac coil system, where the reduced imaging time was traded for improved isotropic resolution.
Artificial intelligence approaches in space power systems automation at Marshall space flight center

Advancements in the field of artificial intelligence (AI) made during this decade have forever changed the way we look at automating spacecraft subsystems including the electrical power system. This paper will discuss various applications of AI to spacecraft electrical power systems. Such discussion will include an overview of various completed, on-going, and planned knowledge-based system activities. These applications include NICBES (Nickel-Cadmium Battery Expert System which is interfaced with the Hubble Space Telescope electrical power system test bed); the SSES (power system loads scheduler); the three cooperating AI systems in the Space Station Module Power Management and Distribution system test bed; and I-DARE, the intelligent data reduction expert. The progress, as well as the issues raised by, of each of these projects will be addressed.
Is this holistic ecology or just muddling through? The theory and practice of marine policy

Abstract An evolution in American values is bringing ever greater attention to concepts of ecosystem management and environmental protection. Changing values have also led to broad new thinking in marine policy; yet curiously, the regime for managing offshore oil and gas development remains fundamentally at odds with this trend. Two principles at the heart of the offshore oil and gas regime are (1) a three‐mile state limit and (2) strict division of state from federal authority. While this divided structure was adequate for limited purposes such as defining neutrality zones of warships, when used for more intrusive purposes such as managing natural resource development in the marine environment, it then becomes much harder to justify. Historic short‐term considerations that led to this structure are reassessed, and assorted classical models of public policymaking are applied to the origins of this regime. Shared state and federal governance is suggested as a preferable regime for offshore oil and gas and ...
The Integration of the European Union and the Changing Cultural Space of Europe: Xenophobia and Webs of Significance

The dialogic relationship between individuals and the cultural space of Europe embodies cultural definitions, political definitions and individual definitions. As individuals draw from Europe as a cultural space and strive to identify and define themselves, definitions are created against an “other,” leading to Europe being defined against the “other.” Identity is established through difference, and in this, the relationship between the EU—a force of integration—and Europe as a cultural space is strained. As boundaries change through the European Union, transforming the cultural space of Europe, the “other” against whom individuals have traditionally defined themselves is also transforming. This article asks if the integration of Europe through the European Union is resulting in the political mobilization of xenophobia and thereby transforming the cultural space of Europe into a xenophobic space. As many academics and professionals have argued that xenophobia in Europe has been on the rise since the 1990s, this paper will question how the relationship between the European Union—as a force of European integration—and Europe—as a cultural space—is contributing to the construction of xenophobia.
Percutaneous core biopsy of the breast: correlates of anxiety.

Abstract Rationale and Objectives The authors performed this study to investigate the level of patient anxiety immediately preceding breast biopsy and examined potential clinical and demographic correlates of anxiety. Materials and Methods The authors evaluated 102 women who were referred to a radiology breast clinic to undergo breast biopsy. The women were assessed with a self-report of demographic and medical items and the State Trait Anxiety Inventory (STAI) immediately before their biopsy. The STAI also was administered at 1 and 5 days after biopsy. Results The participants' mean state anxiety T score as measured with the State Trait Anxiety Inventory was 71.1 (standard deviation, 7.2). Multiple regression analysis was performed to determine the correlates of state anxiety. The variables that showed the strongest correlation with state anxiety were trait anxiety, being concerned about the results of biopsy, education (less education was associated with more anxiety), age (an older age was associated with more anxiety), and number of relatives with breast cancer. Given the expected overlap (r = 0.55) between state and trait anxiety, a second regression analysis was performed that controlled for trait anxiety. The results of this analysis also identified age, being concerned about the results of the biopsy, and number of relatives with breast cancer as relevant correlates of state anxiety. Conclusion Overall, the results give some indication of the characteristics of women likely to be most anxious before biopsy. Future research should assess the effectiveness of different strategies for addressing situational anxiety.
Rebate usage: A motivational perspective

This study investigates the motivational factors in consumer rebate usage. Three motivational factors were identified and tested: price consciousness, perceived time and efforts associated with rebate redemption, and perceived satisfactions from using rebates to obtain the savings. The variables were operationalized by Likert-type statements. Validity and reliability were assessed and found to be acceptable. Moreover, the three factors were found to be useful in predicting consumers' decisions to redeem rebates. Managerial implications and recommendations for future research are offered. © 1994 John Wiley & Sons, Inc.
Study of the human body radar signature variability based on computer models

This paper investigates the variability of the human body radar signature, for both stationary targets (where we are interested in the radar cross section) and moving targets (where we are interested in the Doppler response). The approach in this paper introduces both mesh distortions and variable walking patterns, in order to predict changes in the radar signature induced by morphological changes in the human meshes. The study is based entirely on computer simulations. We start with a basic human mesh and use the Maya software package to articulate or distort the model. Realistic human motion animation is obtained by using spatial coordinates from real motion capture data. The radar signature is obtained by running a Finite Difference Time Domain-based electromagnetic solver. Results are presented as radar cross section for stationary targets or Doppler spectrograms for moving targets.
Aerobic bacterial contamination in dental materials

Current concern about disease transmission points out the need for better infection control in dentistry. The purpose of this study was to test samples of dental materials in factory-sealed containers for aerobic bacterial contamination. Multiple unopened containers of 12 different dental materials were obtained from the dental school dispensary. Samples were removed from each container and incubated at 38 degrees C in standard broth medium for 1 week. Those that exhibited visual signs of possible bacterial growth were subjected to a Gram stain for verification. The results of that test indicated that 20% to 30% of the samples of alginate, glass ionomer cement and base powders, and retraction cord contained bacterial contamination. The remaining eight dental materials exhibited no apparent bacterial growth. Thus viable aerobic organisms were found in samples from 4 of 12 dental material products.
Rv0802C from Mycobacterium Tuberculosis: The First Structure of a Succinyltransferase with the Gnat Fold.

Gene rv0802c from Mycobacterium tuberculosis encodes a 218-amino-acid protein and is annotated as a hypothetical protein with homology to GCN5-related N-acetyltransferases. The structure of Rv0802c was determined in an unliganded form to 2.0 A resolution utilizing single-wavelength anomalous dispersion from a samarium soak that resulted in a single bound Sm3+:citrate2 complex. The structure confirms that Rv0802c exhibits the GCN5-related N-­acetyltransferase fold and revealed a tetramer composed of a dimer of dimers with approximate 222 symmetry. In addition, a bound acetate ion indicated that Rv0802c may utilize a unique acyl donor for the family. The subsequent determination of the structure of Rv0802c in complex with succinyl-CoA to 2.3 A resolution suggests that Rv0802c is the first known GCN5-related N-­acetyltransferase family member to utilize succinyl-CoA as a substrate.
Time-Frequency Analysis for Transfer Function Estimation and Application to Flutter Clearance

Atransferfunction estimationprocedurethatrelies on thetime-frequency analysis of input and output signalsis described. This method was developed in an attempt to better identify the aeroelastic behavior of NASA Dryden’ s F-18 systems research aircraft and to predict its e utter boundaries using in-e ight experimental data. Numerical experimentson e eld data show thatexploiting thetime-frequency characteristics of the excitation inputscan bring enhanced accuracy and cone dence when identifying multi-input/multi-output transfer functions. In particular, the proposed approach complements many well-established black-box identie cation procedures by providing an independent way to obtain transfer function estimates. A computational tool implementing this approach is now being evaluated for practical use at NASA Dryden Flight Research Center.
Diurnal Activity Patterns of Broilers in a Controlled Environment

Abstract THE objective of this study was to determine the patterning of diurnal activity of broilers in a controlled environment. Previous studies (Moore, 1957; Centa et al., 1969; Gore et al., 1969) have indicated that manipulation of background illumination and alternating periods of light and dark may effectively alter activity patterns and growth rates. Indications are that (1) relatively low levels of light are superior and (2) that activity may be synchronized by the use of a “change” cue. Centa et al. (1969) restricted both light and access to feed and found that light control alone was the significant variable. This was interpreted as the result of a direct effect upon activity of the birds. Cumulative sound level recordings of activity (and by inference feeding) patterns demonstrated that behavior was minimal during the no-light periods and maximal during light periods. Weaver and Siegel (1968) had previously reported findings similar to Centa…
Identification and localization of integrin subunits in oocytes and eggs of the mouse

Results of a recent study have implicated egg integrins in sperm binding to the egg plasma membrane (Blobel et al., 1991: Nature 356:248-252). In this report, immunoprecipitation was used to identify, and confocal immunofluorescence microscopy was used to localize, several different integrin subunits in mouse eggs. Antibodies to alpha 2, alpha 5, alpha v, and beta 1 subunits, as well as antibodies to the fibronectin receptor (FNR; alpha 5 beta 1 and/or alpha 3 beta 1) and vitronectin receptor (VNR; alpha v beta 3 and/or alpha v beta 5), detect polypeptides of the appropriate molecular weights following immunoprecipitation. beta 1 is localized preferentially to either the microvillar or amicrovillar membrane/cortical regions of eggs, and these asymmetric localizations depend on the antibody used. Proteins recognized by anti-FNR antibodies are localized preferentially to the amicrovillar membrane/cortical region. Germinal vesicle-intact oocytes display a symmetric plasma membrane distribution using beta 1 and FNR antibodies, and the asymmetric distribution develops as a consequence of oocyte maturation and is clearly observed by metaphase I. In contrast to the membrane localization of these integrin subunits, alpha 2, alpha 5, and VNR are predominantly localized in the cytoplasm of both oocytes and eggs. In the oocyte, each of these integrin subunits is uniformly distributed throughout the cytoplasm. Oocyte maturation is associated with a redistribution of alpha 5 and VNR, leading to an asymmetric cytoplasmic distribution with an increased localization towards the spindle. alpha v, which is localized in the plasma membrane/cortex of both oocytes and eggs, does not show such a change during oocyte maturation. Results of these experiments are discussed in the context of a role for integrins in mediating sperm plasma membrane-egg plasma membrane interactions leading to egg activation.
Evaluation of Six Family-Support Programs: Are They Effective?

Family-support programs employ multiple strategies in an effort to strengthen families and promote the well-being of children. The multidimensionality of these programs—viewed by many experts as a ...
Electron propagator calculations with nondiagonal partial fourth-order self-energies and unrestricted hartree-fock reference states

The capabilities of a new electron propagator program, adapted for use with Gaussian 88, are described. Partial fourth-order self-energies in the diagonal (quasiparticle) approximation for closed-shell Hartree–Fock reference states are extended as follows. First, diagonal and nondiagonal self-energy matrices can now be calculated. Second, unrestricted as well as closed-shell Hartree–Fock reference states can be employed. Full second-order and third-order self-energies are also possible. Computational procedures are described and estimates are given for the number of operations required for the most difficult steps. One-electron pictures and quasiparticle models for open shell systems are tested in calculations on the ionization energies of Cr− and CrH−2.
Differential Control of STIM1 Expression and Function by EGR Family Members in T Cells

Antigen presentation to T cells results in their activation through T Cell Receptor (TCR) stimulation, resulting in an intricate signaling web involving multiple steps and contributors. Elevation in cytosolic Ca2+ concentration is critical for T cell activation and requires Store Operated Ca2+ entry (SOCe). A key mediator of SOCe is the type 1A transmembrane protein Stromal Interaction Molecule 1 (STIM1) that stimulates Orai-mediated Ca2+ entry upon sensing ER Ca2+ store depletion. We have recently shown that STIM1 expression is regulated by a member of the Early Growth Response (EGR) family of zinc finger transcription factors, EGR1. However, examination of T cells collected from EGR1 knockout mice revealed a paradoxical increase in basal level STIM1 expression coinciding with increased expression of EGR4, another EGR family member. We further show that control of STIM1 expression, possibly by multiple EGRs, allows for a compensatory increase of SOCe in EGR1 knockout T cells that is not observed in other cell types such as fibroblasts. This data suggests that STIM1 expression and subsequently T cell function are dynamically regulated through interplay of EGR family members. Given the critical contribution of these Ca2+ signals to both T cell expansion and cytokine production, we anticipate that these findings have significant implications on the T cell activation process itself. We further predict that our findings have important implications towards the general understanding of transcriptional control of Ca2+ signaling.
Seismic effects of the MILROW and CANNIKIN nuclear explosions

Seismic effects of the underground nuclear explosions MILROW (October 1969, about 1 megaton) and CANNIKIN (November 1971, under 5 megatons) were monitored by a network of continuously recording, high-frequency, high-gain seismographs located on Amchitka and nearby islands. Each explosion was immediately followed by hundreds of small, discrete events ( mB < 4), of similar focal mechanism and with a characteristic low-frequency signature, which were apparently related to the deterioration of the explosion cavity. This activity intensified, then terminated within minutes of a large, complex multiple event and concurrent formation of a surface subsided area that signaled complete collapse of the explosion cavity (MILROW, 37 hr; CANNIKIN, 38 hr). A number of small explosion-stimulated tectonic events, apparently unrelated to the collapse phenomenon, occurred intermittently for several weeks following each explosion—near the explosion cavity and up to 13 km southeast of CANNIKIN ground zero along the Island. These events were confined to the upper crust of the Island, had characteristic high-frequency signatures, and, near the Rifle Range Fault, had focal mechanisms which could be correlated with pre-existing faulting. The evidence points to a short-term interaction of the explosions with local ambient tectonic stresses. Because these stresses are of relatively low level on Amchitka, the observed seismic effects were significantly less extensive and smaller than similar effects reported from high-yield explosions at the Nevada Test Site. Continuous monitoring of the natural seismicity of the Amchitka region since 1969 has not revealed other evidence for an interaction between either MILROW or CANNIKIN and natural tectonic processes. The structural stability and apparent low level of stress in the upper crust of Amchitka suggest that the Island effectively is seismically decoupled from the active subduction zone below.
Chemical Mass Shifts in Ion Trap Mass Spectrometry: Experiments and Simulations

Experimental data and simulations of trapped-ion motion are used to characterize the phenomenon of compound-dependent mass shifts in a quadrupole ion trap mass spectrometer. The ratio of axial to radial dimensions of the ion trap and the nature and pressure of the bath gas are identified as experimental variables which influence the chemical mass shift. Systematic changes in chemical shifts occur with changes in the chemical structure of the ion, for example between members of a homologous series of alkylbenzene molecular ions. Simulations, performed using a new version of the program ITSIM, indicate that the mass shift is the result of two interacting factors: (i) delayed ion ejection from the trap during the mass analysis scan due to field imperfections associated with the end-cap electrode apertures and (ii) the compound-dependent modification of this delay by collisions with the bath gas. Both elastic collisions and inelastic collisions, including those which lead to dissociation, appear to contribut...
Barriers to Preventive Health Care for Young Children

Purpose To review the literature on barriers to availability, access, and utilization of preventive health care for young children three to five years of age and their families and to discuss the role of nurse practitioners (NPs) in future research, education, and practice in this area. Data Sources A comprehensive literature search was conducted of online material and CINAHL and Medline (CD-ROM 1990 to present). In addition, experts in this area were asked to recommend extra reading materials. Additional references in textbooks and articles were examined. Conclusions The literature review supports that there are major barriers to be addressed in the areas of availability, access, and utilization of preventive health care services for young children and their families. Major concerns include mandatory system for preventative health care, lack of health insurance coverage, cultural issues, and parental effects. Implications for Practice Health professionals in the community will need to work together to reevaluate current preventive health care practices for young children. Alternative methods for approaching and providing preventive health care services may become increasingly important if these services for young children are to be provided at current or increased levels.
In utero Therapy of Fetal Obstructive Uropathy

The sites of obstruction found during development are reviewed: high (ureteropelvic junction), mid (ureterovesical junction) and low (posterior urethral valves). Diagnostic evaluation of the fetal uri
Communication Network Availability Predictions Based on Measurement Data

Published data describing the probability distributions of data communication system reliability parameters such as availability are very sparse. This paper describes a set of data collected in order to model communication line availability by monitoring operational communication systems. Probability distribution functions for single line availabilities and for the durations of failures are given. A heuristic model for estimating availabilities for more complex systems is presented along with computer simulation data validating the accuracy of the model. The results presented make possible more realistic availability predictions for common types of networks than have previously been computable.
Enhancing Spelling Performance in Students with Learning Disabilities

The present study, using a single subject adapted alternating treatments design, compared the effects of two spelling strategies (cover, copy, compare, and copy-only) used to enhance spelling performance in 2, third-grade students with learning disabilities. The cover, copy compare (CCC) method required the students to say the word, point to the word, repeat the word, cover the word, print the word, compare the word to the correct model, and correct errors if necessary. The copy-only method required the students to say the word, point to the word, repeat the word, and print the word. Overall, the CCC strategy was more effective in words learned and words retained. Results are discussed in light of CCC requiring a self-evaluation/self-correction component not required in the more traditional method of instruction. By incorporating a simple, self-management component to spelling instruction, teachers may improve spelling performance in the classroom.
Effects of isoeugenol on oxidative stress pathways in normal and streptozotocin-induced diabetic rats.

Because some complications of diabetes mellitus may result from oxidative damage, we investigated the effects of subacute treatment (10mg/kg/day, intraperitoneal [ip], for 14 days) with the antioxidant isoeugenol on the oxidant defense system in normal and 30-day streptozotocin-induced diabetic Sprague-Dawley rats. Liver, kidney, brain, and heart were assayed for degree of lipid peroxidation, reduced and oxidized glutathione content, and activities of the free radical–detoxifying enzymes catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase. All tissues from diabetic animals exhibited disturbances in antioxidant defense when compared with normal controls. Treatment with isoeugenol reversed diabetic effects on hepatic glutathione peroxidase activity and on oxidized glutathione concentration in brain. Treatment with the lipophilic compound isoeugenol also decreased lipid peroxidation in both liver and heart of normal animals and decreased hepatic oxidized glutathione content in both normal and diabetic rats. Some effects of isoeugenol treatment, such as decreased activity of hepatic superoxide dismutase and glutathione reductase in diabetic rats, were unrelated to the oxidative effects of diabetes. In heart of diabetic animals, isoeugenol treatment resulted in an exacerbation of already elevated activities of catalase. These results indicate that isoeugenol therapy may not reverse diabetic oxidative stress in an overall sense. © 2001 John Wiley & Sons, Inc. J Biochem Mol Toxicol 15:159–164, 2001
Identification of kainate-preferring glutamate receptor subunit GluR7 mRNA and protein in the rat median eminence

In situ hybridization and immunohistochemistry were used to determine the presence of kainate-preferring glutamate receptor subunits GluR6 and GluR7 mRNA and protein in the median eminence of the rat. The results show that most tanycytes lining the ventral third ventricle and many astrocytes within the median eminence contain the GluR7 receptor subunit mRNA but not the GluR5 and GluR6 receptor subunit mRNA. Immunohistochemical stainings show that the GluR6/7 receptor protein was localized to tanycytic cell bodies, their basal processes and to many other astrocytes in different layers of the median eminence. The results suggest that glutamate can act directly on the glial cells in the median eminence by binding to the GluR7 subunit which may be important for the control of the secretion of releasing and inhibiting hormones from axon terminals in the external layer. In order to determine if these receptor subunits are functional, kainic acid was injected and c-fos expression monitored. Results show that kainic acid induced c-fos synthesis in most of these glial cells.
Simulation of melt pond evolution on level ice

[1] A melt pond model is presented that predicts pond size and depth changes, given an initial ice thickness field and representative surface fluxes. The model is based on the assumption that as sea ice melts, fresh water builds up in the ice pore space and eventually saturates the ice. Under these conditions, a water table is defined equal to the draft of the ice or sea level, and ponds are produced in ice surface depressions, much like lakes in a watershed. Pond evolution is forced by applying fluxes of heat at the pond surface and a radiative transfer model for solar radiation that penetrates the pond. Results from the model using forcing data from the Surface Heat Budget of the Arctic Ocean (SHEBA) experiment and representative pond parameters indicate that the model accurately simulates pond depth and fractional area over the summer melt season, with fractional area increasing linearly. Overall, ice albedo is affected primarily by the increase in pond coverage. Decrease in pond albedo from pond deepening has a much lower influence on the total albedo. Cases with predominately sunny conditions are shown to produce more rapid pond expansion than overcast cases. In both sunny and cloudy cases the fractional area increases linearly.
Fluidization of fine powders with air in the particulate and the bubbling regions

Several fractions of a silica—alumina catalyst and an impregnated catalyst were fluidized with air to check published bubble point correlations and to determine the expansion of the dense phase in the bubbling region. The minimum bubbling velocities were fairly close to those reported by Geldart and others, but Umb varied with only the 0.6 power of the particle size. The dense phase expansion was significant even at velocities much above Umb and corresponded to relative velocities up to 2 – 3 times Umf.
Precise and Scalable Static Program Analysis of NASA Flight Software

Recent NASA mission failures (e.g., Mars Polar Lander and Mars Orbiter) illustrate the importance of having an efficient verification and validation process for such systems. One software error, as simple as it may be, can cause the loss of an expensive mission, or lead to budget overruns and crunched schedules. Unfortunately, traditional verification methods cannot guarantee the absence of errors in software systems. Therefore, we have developed the CGS static program analysis tool, which can exhaustively analyze large C programs. CGS analyzes the source code and identifies statements in which arrays are accessed out of bounds, or, pointers are used outside the memory region they should address. This paper gives a high-level description of CGS and its theoretical foundations. It also reports on the use of CGS on real NASA software systems used in Mars missions (from Mars PathFinder to Mars Exploration Rover) and on the International Space Station
Optimal path planning for an unmanned aerial vehicle

This paper presents an extended approach of local optimization strategy (ELOS) for generation of a collision free shortest distance path for the unmanned aerial vehicle (UAV). Autonomous vehicles are being used to perform missions in hazardous environments. The real task lies in generating an optimal path in these adversarial environments. Since the UAV operates in a dynamic environment, the ELOS aims at an optimal collision free path, with emphasis on the varying positions of the obstacle. The ELOS generates the path, depending on two factors: onboard sensory measurements of the position of the obstacle at each instant of time and the distance to destination. Simulation results show that ELOS can be effectively used as an optimal path generation strategy for UAVs functioning in dynamic environments.
Archipelago: an Island-based file system for highly available and scalable internet services

Maintaining availability in the face of failures is a critical requirement for Internet services. Existing approaches in cluster-based data storage rely on redundancy to survive a small number of failures, but the system becomes entirely unavailable if more failures occur. We describe an approach that allows a cluster file server to isolate failures so that the system can continue to serve most clients. Our approach is complementary to existing redundancy-based methods: redundancy can mask the first few failures, and failure isolation can take over and maintain availability for the majority of clients if more failures occur. The building blocks of our design are self-contained and load-balanced file servers called islands. The main idea underlying island-based design is the one-island principle: as many operations as possible should involve exactly one island. The one-island principle provides failure isolation because each island can function independently of other islands' failures. It also helps the file system scale with the system and workload sizes because communication and synchronization across islands are reduced. We implemented a prototype island-based file system called Archipelago on a cluster of PCs running Windows NT 4.0 connected by Ethernet. The measurement of micro benchmark shows that Archipelago adds little overhead to NTFS and Win32 RPC performance; while the measurement of operation mixes based on NTFS traces shows a speedup of 15.7 on 16 islands
Seasonal relationships between leaf nitrogen content (photosynthetic capacity) and leaf canopy light exposure in peach (Prunus persica)

Abstract Field gas exchange measurements on intact peach (Prunus persica (L.) Batsch) leaves indicate that leaf nitrogen content (NL) and leaf weight per unit leaf area (Wa) are highly correlated with CO2 assimilation rate (A) and mesophyll conductance (gm). Therefore, NL and Wa were used to study seasonal relationships between leaf carboxylation capacity and natural light exposure in tree canopies. From mid-season onwards, NL and Wa were linearly correlated with light exposure expressed as the amount of time during a clear day that a leaf was exposed to a photosynthetic photon flux density (Q) of ≥ 100 μmol m−2 s−1. The data support the hypothesis that whole-tree photosynthesis is optimized by partitioning of photosynthetic capacity among leaves in deciduous tree canopies with respect to natural light exposure.
At the crossroads: AMP-activated kinase and the LKB1 tumor suppressor link cell proliferation to metabolic regulation

The tumor suppressor kinase LKB1 has been identified as a physiologic activator of the key metabolic regulator 5'-AMP-activated protein kinase, establishing a possible molecular link between the regulation of metabolism and cell proliferation.
Lipid Droplets and Cellular Lipid Metabolism

Among organelles, lipid droplets (LDs) uniquely constitute a hydrophobic phase in the aqueous environment of the cytosol. Their hydrophobic core of neutral lipids stores metabolic energy and membrane components, making LDs hubs for lipid metabolism. In addition, LDs are implicated in a number of other cellular functions, ranging from protein storage and degradation to viral replication. These processes are functionally linked to many physiological and pathological conditions, including obesity and related metabolic diseases. Despite their important functions and nearly ubiquitous presence in cells, many aspects of LD biology are unknown. In the past few years, the pace of LD investigation has increased, providing new insights. Here, we review the current knowledge of LD cell biology and its translation to physiology.
Light reduction and the electroretinogram of preterm infants

AIMS To examine the effects of light on retinal development and function in preterm infants as measured by the electroretinogram (ERG). Secondary outcomes included visual acuity testing, the incidence of retinopathy of prematurity, and general wellbeing, reflected in feeding tolerance, rate of weight gain, and length of hospital stay. METHODS Eligibility criteria for enrolment were birthweight ⩽ 1250 g and gestational age ⩽ 31 weeks. Sixty one infants were randomly allocated by 6 hours after birth to a control or treatment group which wore 97% light filtering goggles for a minimum of four weeks or until the infant reached 31 weeks postmenstrual age. RESULTS There were no significant differences between the two groups in the numbers of electroretinograms performed at 36 weeks of postmenstrual age. Although the sample size was not large enough to exclude clinically important differences in secondary outcomes, no significant differences were observed between the groups in visual acuity testing at 4-6 months corrected age, incidence of retinopathy of prematurity, weight gain, or length of stay. CONCLUSION These data support the safety and feasibility of this intervention. A much larger study will be needed to determine whether light reduction to the eyes of very low birthweight infants will reduce the incidence of retinopathy of prematurity or enhance general wellbeing.
FI-based file access predictor

An algorithm is proposed for the purpose of optimizing the availability of files to an operating system prior to their being required during execution by a running system. This algorithm is a first step in optimizing speed using a prefetching scheme based upon previous history of access. The technique described utilizes a mathematically based approach considering the actual occurrence of file application patterns. This technique was defined for pattern matching, and prefetching of files is indeed a pattern matching problem. We utilize the technique of Finite Inductive Sequences which is defined within the body of this paper. We also note that the formulation for the approach is defined and included, actual data for comparisons are still not completed as of the writing of this paper. However, we believe that the richness of this approach will be useful in considering how to prefetch multiple files for multiple applications under one system.
The experimental treatment exclusion clause. A tool for silent rationing of health care

(1991). The experimental treatment exclusion clause. Journal of Legal Medicine: Vol. 12, No. 3, pp. 359-418.