cssi/SciSciGPT-SciSciNet huggingface dataset:
Metabolism of diphenylhydantoin by rat liver microsomes. I. characteristics of the reaction.

Abstract Biotransformation of diphenylhydantoin (DPH) is an essential step preceding its elimination. The kinetic characteristics of this reaction by rat liver 9000 g supernatant are presented. The system in vitro produced 5-phenyl-5′ parahydroxy-phenylhydantoin (HPPH) as the reaction product. The optimal pH for this reaction was 7.4 and temperature 37†. The cofactors included NADP, NAD, ATP and oxygen; and the final reaction mixture had a protein content of 8–10 mg per ml. The K m of this system calculated from 16 Lineweaver-Burk plots ranged from 3 × 10 −5 M to 5 × 10 −5 M with a mean of 3.73 ± S.D. 0.18. The washed microsomes metabolized DPH only when NADPH generating systems were added. The 120,000 g supernatant centrifuged for 30 min retained a portion of its enzymatic activity which was 40 per cent of that of 9000 g supernatant. No DPH was metabolized by 120,000 g supernatant centrifuged for 3 hr or longer. The reaction was inhibited by methylene blue, sodium azide and SKF 525-A; and a number of commonly used drugs. The inhibition of SKF 525-A was noncompetitive, whereas phenobarbital caused competitive inhibition. Other drugs which inhibited strongly were prochlorperazine, chlordiazepoxide, diazepam, chlorpromazine, isoniazid, propoxyphene, diethylstilbestrol, disulfiram and dimenhydrinate. These findings help to elucidate the mechanism of the clinically observed DPH accumulation and intoxication in some patients using isoniazid, tranquilizers or other drugs in combination with DPH.
Antigenic structure of flavivirus proteins.

The increased activity of Dengue virus in the tropical regions of the world and the recent movement of West Nile virus from the eastern to the western hemisphere emphasize the fact that vector-borne flaviviruses are medically important emerging infectious diseases. These facts warrant continued efforts to decode all facets of flavivirus immunology. This chapter reviews current understanding of the antigenic fine structure of flaviviral structural and nonstructural (NS) proteins and their involvement in B- and T-cell host responses. The virion structural glycoprotein E elicits both virus-neutralizing antibodies and antiviral TH-cell responses. Consistent with the current hypothesis of the MHC class I pathway of protein processing, immunodominant flaviviral TC-cell epitopes mainly reside on the NS proteins. To prepare effective and inexpensive subunit vaccines, we will need to continue to better understand these structure–function relationships of flavivirus proteins.
Youth perceptions of how neighborhood physical environment and peers affect physical activity: a focus group study

There is need for a youth-informed conceptualization of how environmental and social neighborhood contexts influence physical activity. We assessed youths’ perceptions of their neighborhood physical and peer environments as affecting physical activity. Thirty-three students (20 girls; ages 12-14 years) participated in focus groups about the physical environment and peers within their neighborhoods, and their understanding of how they affect physical activity. Inductive analysis identified themes of access (e.g., to equipment); aesthetics; physical and social safety; peer proximity and behavior (e.g., bullying); adult support or interference; and adult boundary setting. Participants also identified interconnections among themes, such as traffic shaping parent boundary setting and, in turn, access to physical spaces and peers. Young adolescents view neighborhoods in ways similar to and different from adults. Examining physical and social environments in tandem, while mindful of how adults shape and youth perceive these environments, may enhance understanding of youth physical activity behavior.
Evaluating the Importance of Image-related Text for Ad-hoc and Case-based Biomedical Article Retrieval

Images and their associated text are an essential source of information in biomedical articles. However, their use in providing evidence for clinical case descriptions has yet to be evaluated in the context of information retrieval. Given the complexity of case-based document retrieval, understanding the importance of images and image-related text is critical for future research into text- and content-based approaches to this problem. In this study, we compare the extent to which image-related text is useful in facilitating document retrieval for both case-based information requests and ad-hoc clinical questions in the domain of family practice. We show that case-based document retrieval is significantly improved with the use of image-related text whereas retrieval for clinical questions is largely unaffected. This suggests that visual evidence is more relevant for the case descriptions used in our study than the clinical questions.
Focus on their promise : how Mexican American teachers address challenging classrooms

This study examined the culturally responsive teaching practices of two third generation Mexican American teachers from the South Texas borderlands region. The study presents the contextualized teaching practices that inform institutions of higher education prepare pre-service teachers entering the diverse classrooms in America. The implications of this study are to expand and substantiate how contextual teaching practices can help present and future teachers develop human agency that maximizes cultural wealth to positively impact the academic success of high needs-students. Central to this study is the generational and cultural variance that exists among Mexican American teachers in terms of their cultural awareness and teaching practices. In fact, the review of the literature revealed that institutions of higher education need to understand that teachers of color will not naturally assume culturally relevant practices in their classroom because they were not raised in a culturally diverse household but in an acculturated home.
New results from AGS heavy-ion experiments

Abstract We review the most recent data from Experiments 802, 810 and 814 of the heavy-ion program at the Brookhaven Alternating Gradient Synchrotron (AGS).
Mathematical and computational modelling of correlations in dislocation dynamics

This work focuses on the mathematical and computational modelling of dislocation correlation in the context of dislocation dynamics modelling of mesoscale plasticity. A hierarchical system of kinetic equations describing the evolution of dislocation densities of various orders is presented to illustrate the role of correlation in dislocation dynamics, which is followed by a mathematical description of the spatial and line-orientation statistics of dislocation systems within the framework of stochastic fiber processes. In this framework, the pair correlation is related to the second moment measure of the dislocation distribution in the crystal and dislocation line-tangent spaces. The stochastic fiber process description of correlation is used in conjunction with the method of dislocation dynamics simulation to compute the pair correlation in both face-centered cubic and body-centered cubic crystals undergoing small homogeneous plastic deformation at a constant rate. An edge correction scheme is employed as part of the overall methodology for computing the pair correlation. The main characteristics of correlations, including its oscillatory behavior, anisotropy and symmetry, are studied in detail. The self-correlation and cross correlation of dislocations of various species are compared. The implications of the present results for the development of kinetic theory of dislocations are discussed.
An active learning strategy for the classroom—“who wants to win … some mini chips ahoy?”

Abstract Skillfully presenting technical accounting material has been identified as an important dimension of effective teaching [Issues in Accounting Education (1993) 8(2), 436]. Faculty may more effectively present material by modifying the traditional lecture approach to incorporate visual-based instruction and increase student involvement through active learning exercises. One approach to presenting accounting material more effectively is described in this article. A “Who Wants to Win…?” game, similar to that seen on television, is constructed with the instructor in the role of master of ceremonies and one class member, a group, or the entire class in the role of contestants. The method described can be adapted and used to present a variety of accounting topics. Anecdotal evidence from two very different college classroom settings indicates a high level of student enjoyment, increased class participation, and an increased level of advance preparation on the part of the students. While a significant amount of material is presented in a concise, novel, and effective manner, the game provides a relaxed classroom atmosphere for the students and an enjoyable method of presentation for the instructor.
Fast co-test of linearity and spectral performance with non-coherent sampled and amplitude clipped data

Production test is a significant contributor to the manufacturing cost for high performance analog and mixed-signal products. Linearity test and spectral test are two main categories in ADC testing, and linearity test cost is usually the largest component in the test cost. For spectral testing, it is a very challenging task to precisely control the amplitude and frequency of input sinusoidal signal. Over-range amplitude results in clipping ADC output and non-coherent sampling results in spectral leakage. To reduce ADC test cost dramatically, a new algorithm is proposed in this paper. The new algorithm can simultaneously perform linearity test and spectral test with only one-time data acquisition. Targeted for realizing co-test of linearity and spectral performance under non-coherent sampling and amplitude clipping, a new accurate method for identifying the non-coherent and clipped fundamental is introduced. The residue after removing the identified fundamental from raw data is used to obtain the linearity and spectral characterizations. Simulation results and measurement results against the standard test methods collaborate to validate the accuracy and robustness of the new solution
The analysis of variation in cultivated plants with special reference to introgression

That introgressive hybridization played an important role in the origins and further development of cultivated plants is a likely hypothesis, yet at present we need to gather new kinds of evidence by analysis and experiment. Three likely directions are suggested. (1) The study of the origins of cultivated ornamentals. Some ornamental plants are among our oldest domesticates; others have been domesticated within the last century. These latter are valuable material on which to determine the steps in domestication and the resulting changes in the germplasms. As an example well worth further study, the Louisiana irises are now well established as a group of cultivated varieties. Introgression in disturbed habitats under the impact of man produced recombinants of more than local interest. This stimulated further collection and controlled breeding. (2) Analysis of variation. Analysis of variation complexes (by means of metroglyphs) in variable populations give critical data on domestication. This is illustrated in detail for a variable semi-wild population of coffee in Ethiopia, readily resolvable into two introgressing complexes. (3) Field variability studies in the small grains. Our present understanding of variation patterns in the small grains is based upon individual specimens collected here and there from varying populations. Particularly near their centers of variability, we need to have scrupulously careful studies of a few populations from which such samples were drawn. The durum wheat fields in Ethiopia, as an example, are shown to consist of mixtures of bread and durum wheats, frequently including barley and sometimes lesser millets. They are sown as mixtures, reaped as mixtures, brewed and baked as mixtures. In fields of such complexity, opportunities for introgression are greatly increased. We should perhaps be thinking about the origin of the small grains as a group.
Trimethyltin induced hippocampal neurodegeneration elevates cyclins A and B

In certain pathologic states, the response of microglia and associated cytokine production may become spatially and temporally dysregulated contributing to neurodegeneration. Often these responses have been contributed to proliferation of microglia cells. To examine cell cycle related genes and proteins in a model of acute neurodegeneration, the hippocampal toxicant, trimethyltin (TMT; 2.0 mg/kg), was administered to 21 day old CD-1 male mice and the level of cell cycle genes and cellular localization of proteins examined. Neurodegeneration was characterized by neuronal necrosis in the dentate followed by microglia reactivity and activation. mRNA levels for cyclins A2 and B1 were significantly elevated 72 h post-TMT. Western blot analysis indicated minimal increase in whole hippocampal protein levels for cyclin A or B however, immunohistochemical examination of cellular localization demonstrated increased staining for cyclin A primarily in neurons in both the dentate and pyramidal cell layers as early at 24 h post-TMT. Immunohistochemisttry for cyclin B1 showed a peak level of staining at 24 and 48 h in both the dentate and pyramidal cell layers with prominent staining both around the neuronal cell body and in fibrous processes. The staining pattern for each cyclin suggested the involvement of both neurons and microglia. BrdU positive cells were demonstrated predominately in the dentate region and appeared to be primarily neurons with minimal contribution from microglia cells suggesting that the alteration in cell cycle genes is not due to an injury-induced proliferative response of microglia cells in the hippocampus.
Determination of doubly labeled water by gas-phase Fourier transform infrared spectroscopy.

Both 2H (deuterium) and 18O (oxygen 18) in isotopically enriched water have been detected by gas-phase Fourier transform infrared (FTIR) spectroscopy at 2,720 and 3,661.8 cm−1, respectively. A linear relationship between varying concentrations of each of these isotopes and their absorbance at the above frequencies indicates that gas-phase FTIR may provide a rapid and potentially less expensive approach to measure doubly labeled water in biological fluids for the estimation of energy expenditure and total body water.
Atypical regulation of SRC-3

Overexpression of steroid receptor coactivator 3 (SRC-3) is associated with an increased incidence of breast cancer. A recent study shows that SRC-3 is protected from proteasomal degradation by atypical protein kinase C (aPKC)-mediated phosphorylation in an estrogen receptor α (ERα)-dependent manner. This finding provides a novel mechanism for coupling increased SRC-3 expression with enhanced estrogen-dependent cellular proliferation.
The Endangered Species Act and the National Research Council's Interim Judgment in Klamath Basin

Abstract The controversial 2001 U.S. Fish and Wildlife Service water allocation decision in the Klamath Basin has been portrayed as an example of scientific guesswork operating under a flawed Endangered Species Act. This conclusion has been based on an interim National Research Council report, quickly prepared in late fall 2001. We have reviewed several iterations of the NRC Interim Report as well as all Biological Opinions and management documents related to Klamath Basin suckers and provide an overview. The 2001 Biological Opinion and the Interim Report illustrate the lack of consensus typical of scientists in the early stages of exploring a complex system. Unfortunately, the Biological Opinion created hardship for a small group of people and the lack of scientific consensus has politicized the debate. Politicians have assumed that the Interim Report has primacy in the scientific debate when, in fact, its speedy construction contributed to multiple errors that detract from its scientific usefulness. The...
Relational messages associated with nonverbal involvement, pleasantness, and expressiveness in romantic couples

Previous research suggests that individual nonverbal cues and cue complexes communicate multiple relational messages simultaneously. This work examines the contention that nonverbal percepts may predict relational message interpretations in romantic relationships. Results provide support for the hypothesis that nonverbal cues indicative of greater involvement, pleasantness, and expressiveness connote messages of intimacy. Specifically, the current study reveals that perceptions of intimacy and composure are associated with greater vocalic involvement. Interpretations are provided in line with the social meanings model.
Association of normal serum protein antigens with chimpanzee hepatitis B surface antigen particles.

HBsAg/adw was purified from 2.6 liters of pooled plasma from a single chimpanzee carrier by polyethylene glycol (PEG) precipitation followed by isopycnic and rate zonal centrifugation. The different morphological populations of HBsAg separated in the final rate zonal centrifugation step were combined into seven pools: two fractions rich in filaments and Dane particles, two pools composed of filaments and 20–28-nm spheres, and three fractions containing mostly 20–28-nm spheres. The purified preparations of HBsAg analyzed for normal serum protein contaminants revealed albumin and traces of IgG. The same samples, analyzed after Tween-80 treatment, revealed enhanced quantities of the previous two contaminants, and in addition, transferrin, traces of α2-macroglobulin, IgM, and complement (C3/C3c). The residual contaminants were mostly removed by further purification and fractionation after detergent treatment using zone convection electrofocusing and rate zonal centrifugation. Our findings indicate that conventional purification techniques will not provide preparations of HBsAg free of traces of serum protein contaminants. Many of these are released only by detergent treatments and subsequent purification. It is not yet clear whether detergents release these contaminants from the interior of the particles or from firm association or incorporation within the membranes.
Sensitivity-bandwidth product for electro-optic modulators.

For lumped-element electro-optic modulators, the sensitivity ∂ϕ/∂V of the phase, ϕ, in response to an applied voltage V is related to the optical group delay, Tg, and the bandwidth, Δω. This relationship imposes a fundamental trade-off between the sensitivity and the bandwidth of electro-optic modulators: ∂ϕ/∂VΔω=dn/dVω/n, where n is the optical index. A similar relationship for traveling-wave modulators sets an upper limit on ∂ϕ/∂V that is proportional to Tg.
Length-Scale Dependence of Elasticity in Nanocrystalline Materials for MEMS Applications

Length-scale dependence of the elastic properties of thin film materials bears significance in the design of Microelectronic and Micro-electro-mechanical (MEMS) systems, which are usually desired to operate in the elastic range under different operational loading conditions. In this study, we investigate elastic properties of freestanding ultra-high purity Aluminum and Gold thin films with thickness varying from 30 to 350 nanometers. Uniaxial tension test results indicate that for truly polycrystalline films, Young’s modulus can be as low as 85% and 60% of the bulk value for Aluminum and Gold respectively with average grain size of 20 nanometers. We present, for the first time, the evidence of non-linear elasticity with total strain up to 1.0% in nanocrystalline thin films and attempt to provide fundamental understanding of the length-scale dependence of elasticity in thin films with a simple model based on inter-atomic force-distance relationships.Copyright © 2002 by ASME
How Bias Shapes the News: Challenging the New York Times' Status as a Newspaper of Record on the Middle East

This article addresses bias in the American press and shows how the inevitability of reporting from a point of view challenges the possibility of a newspaper of record on the Middle East. Examining 30 days of coverage of the Intifada, it both shows that coverage of events varied across three mainstream US newspapers – The New York Times, The Washington Post and Chicago Tribune – and demonstrates that in the case of the newspaper most often called a newspaper of record – The New York Times – coverage varied in distinct ways from other mainstream newspapers. The article thus considers how the Times' reputation and influence converge with its record in creating a broader impression about the perspective of the US press on the Middle East.
Stress-assisted and strain-induced martensite morphologies in an Fe--21Ni--0. 6C alloy

Abstract Morphologies resulting from the transformation of austenite to martensite during deformation of an Fe-21Ni-0.6C alloy are described. Samples were deformed either by conventional quasistatic tension loading, by high-strain-rate inertial tension loading, or by flyer-plate, compression shock loading. The various martensites observed are classified either as stress-assisted or strain-induced martensite. The stress-assisted martensite is characteristic of the plate martensite formed by lowering the temperature below the Ms of the alloy. The strain-induced martensite, which forms only during plastic deformation, appears as laths or platelets, but with different morphologies in the tension-loaded and shock-loaded samples. In the tension-loaded, deformed samples, the laths are clustered within the deformation bands. In the shock-loaded samples, arrays of relatively thin, long laths, where observed, aligned parallel to the {111}γ twin boundaries of the more homogeneously deformed parent austenite. Where both martensites are present, the strain-induced martensite appears to have formed prior to the stress-assisted martensite. Differences in morphology between the shock-loaded and nonshock-loaded samples are ascribed to differences in the extent of dislocation generation and movement.
Simple adjuncts which maintain septal temperature below 20° C during ischemic arrest for coronary artery bypass grafting

Abstract One of the key elements of intraoperative myocardial protection is maintaining myocardial temperature below 20° C during ischemic arrest; however, many diverse techniques have been advocated to achieve this goal. One hundred and thirteen patients undergoing myocardial revascularization with one period of ischemic arrest were randomized: group A (n = 52) received continuous (150 to 200 cc/min) profound (4° C) topical hypothermia and group B (n = 61) received identical topical hypothermia plus one initial 500 cc aortic root bolus of cold (4° C) hyperkalemic cardioplegic solution. Perfusion technique was identical for both groups. The two groups were statistically indistinguishable when 30 preoperative and intraoperative characteristics were compared, including the distribution and number of vessels diseased, degree of left ventricle dysfunction, average number of coronary artery bypass grafts, aortic crossclamp times, and cardiopulmonary bypass times. Myocardial septal temperature (° C ± SD) was measured following each distal anastomosis. For group A the values were 29.6 ± 2.7° C for the first anastomosis, 24.4 ± 2.7° C for the second anastomosis, 20.8 ± 2.57° C for the third anastomosis, and 21.5 ± 3.3° C for the fourth anastomosis (p
Underutilizers of mammography screening today: Characteristics of women planning, undecided about, and not planning a mammogram

Using concepts from the Precaution Adoption Process Model, we identified behavioral factors, sociodemographic and psychosocial variables, and beliefs about breast cancer that discriminated among women at different stages with regard to their intention to obtain mammography screening. An independent survey company conducted telephone interviews with 2,507 women aged 50 to 80 who were identified as underutilizers of mammography screening. Each underutilizer was assigned to one of three stages with regard to intention to get a mammogram: (a) definitely planning, (b) thinking about, and (c) not planning. Estimated actual risk of breast cancer, perceived risk to breast cancer, worry about breast cancer, and fear of learning from a mammogram that one has breast cancer were variables found to be significantly associated with intention to obtain a mammogram for several subgroups of underutilizing women. There are significant behavioral and psychosocial variables, beliefs and feelings about breast cancer, and demographic characteristics that distinguish underutilizing women at various stages with regard to intention to obtain mammography screening. Our findings provide new information that could help the health care professional motivate women who are not planning to utilize this preventive health measure to become regular utilizers.
On non-renormalization theorems for four-dimensional superstrings

Abstract For d =4, N =1 supersymmetric string theories we compute the quantum corrections to the superpotential to two-loop order. The vanishing of the amplitudes relies crucially on generalized Riemann identities. Beyond genus one, these map to non-trivial zeroes of theta functions implied by the Riemann vanishing theorem.
The Effect of Graded Strength on Damage Propagation in Continuously Nonhomogeneous Materials

A damage model developed by Johnson and Holmquist is implemented into a dynamic finite element code. This is then used to study the effect of grading of the phenomenological damage parameters on the propagation of damage through the material. The numerical results for two one-dimensional example problems with different boundary conditions are presented, wherein the effect of a gradient in the intact strength of the material on damage propagation is studied. The results show that introducing different strength gradients can alter the location of the site of maximum damage. This may have important implications in the design of impact resistant materials and structures.
Metabolic Clearance Rate and Urinary Clearance of Purified β-Core

We injected a highly purified preparation of the β-core molecule, a fragment of hCGβ excreted in pregnancy urine, into five men and three women to determine its kinetic parameters, MCR, and urinary clearance. The β-core molecule was distributed in an initial volume [1950+−156 (mean+−SEM) mL/m2 body surface area] approximately equal to the estimated plasma volume. Its disappearance was multiexponential on a semilogarithmic plot, with a rapid phase t½ of 3.5+−0.7 min and a slow phase t½ of 22.4+−4.2 min. The transit time (the mean time spent by a molecule of β-core in transit) was 20.6+−2.1 min. The MCR was 192.0+−8.0 mL/min-m2 body surface area. About 5%of the injected dose of β-core was excreted into the urine in the first 30 min after injection, and low levels of excretion persisted for up to 7 days. The urinary clearance rate of β-core was 13.7+−1.4 mL/min-m2, accounting for about 8%of the elimination of β-core from the plasma. The β-core immunoreactivity in serum and urine was characterized by gel filt...
Quantum efficiency simulations from on-line compatible mapping of thin-film solar cells

Through-the-glass and film side spectroscopic ellipsometry (SE) are being developed as in situ, on-line, and off-line mapping tools for large area thin film photovoltaics. Given that such instrumentation allows one to extract thicknesses, as well as parameterized optical functions versus wavelength, there exists the possibility to utilize this information further to predict the optical quantum efficiency (QE) and optical losses, the latter including the reflectance and inactive layer absorbances. By spatially resolving this information, one can gain a better understanding of the origin of performance differences between small area cells and large area modules. We have demonstrated these techniques for thin film hydrogenated amorphous silicon (a-Si:H) and Cu(In 1−x Ga x )Se 2 solar cell structures. For solar cells on glass superstrates, film-side SE can be supplemented with through-the-glass SE, which helps to increase the sensitivity of the analysis to the critical transparent conducting oxide and window layer properties. A comparison of predicted and experimental QE can reveal optical and electronic losses and light trapping gains.
Fractionation of oils in hydraulic pressing

The foregoing results may be taken to indicate that in so far as cottonseed oil is concerned the fractions of oil obtained from the hydraulic press at different periods during the operation show some definite variations in some of their physical characteristics but nothing conclusive is shown by the chemical constants The salient facts brought out may be summarized as follows: (1) The color of the crude oil increases as the press operation nears completion. The index of refraction also increases slightly but consistently. (2) Considerable variations occur in the pereentage of free fatty acids, saponification and iodine values but the variations occur without any definite relationship to the various fractions. (3) The refining losses by the cup method were lowest in the case of the first two fractions but the absolute refining-loss method showed a higher percentage of neutral oil in the last fraction than in any of the others. (4) The color of the oil from the several fractions shows only moderate differences after refining with caustic; the last fractions from the press showed very nearly the same amount of red as the first fraction. Fuller’s earth, however, did not bleach the last fractions of oil quite so much as those obtained earlier in the operation.
Previous ectopic pregnancy as a predictor of failure of systemic methotrexate therapy.

Abstract Objective To investigate whether a history of previous ectopic pregnancy is an independent risk factor for failure of methotrexate therapy in subsequent ectopic pregnancies and whether the previous treatment method influenced failure. Setting Inner-city teaching hospital. Design Retrospective case review. Patient(s) Five hundred four consecutive patients treated with "single-dose" methotrexate for ectopic pregnancy. Nine patients electing surgery after beginning medical therapy were excluded from analysis. Intervention(s) Systemic methotrexate 50 mg/m 2 . Main outcome measure(s) Failure of methotrexate therapy. Result(s) Twenty-one (18.6%) of 113 of previous ectopic patients and 26 (6.8%) of 382 first-time ectopic patients failed methotrexate therapy (odds ratio, 3.12). The overall success rate was 90.5% (448/495 patients). Univariant analysis showed that treatment hCG and progesterone (P) levels and ectopic cardiac activity were significantly different between successful and failed therapy. Logistic regression analysis for these four variables showed that only hCG and history of previous methotrexate remained significant risk factors for failure of methotrexate therapy. The likelihood of failure in patients with a previous ectopic was not influenced by previous treatment with salpingostomy, salpingectomy, or medical treatment. Conclusion(s) A history of previous ectopic pregnancy appears to be an independent risk factor for failure of systemic methotrexate treatment, but failure is not affected by previous treatment method.
Numerical modeling of water quality and sediment related processes

Abstract A three-dimensional water quality model (CCHE3D_WQ) was developed for simulating temporal and spatial variations of water quality with respect to phytoplankton, nutrients, and dissolved oxygen. Four major interacting systems were simulated, including phytoplankton dynamics, nitrogen cycle, phosphorus cycle, and dissolved oxygen balance. The effects of suspended and bed sediment on the water quality processes were also considered. The model was verified using analytical solutions for the transport of non-conservative substances in open channel flow, and then calibrated and validated by applying it to the study of the water quality of a natural shallow oxbow lake. The simulated time serial concentration of phytoplankton (as chlorophyll) and nutrients were generally in good agreement with field observations. Sensitivity studies were then conducted to demonstrate the impacts on water quality due to varying nutrients and suspended sediment loads to the chlorophyll concentration.
Origin of room-temperature ferromagnetism in cobalt-doped ZnO

Thin films of ZnO doped with cobalt have been grown by the pulsed laser deposition (PLD) technique in different temperatures ranging from 500°C to 650°C. The films grown on sapphire c-plane single crystal were found to be highly epitaxial. Magnetic properties of these films were studied, and the films exhibited ferromagnetic characteristics at room temperature. Detailed structural and microstructural characterization was performed to correlate the fate of the magnetic impurities, i.e., cobalt, and the cause of magnetic properties. It is established from this work that the magnetic properties of these films are inherent to the system, and any presence of second phase/nanoclusters/precipitates are ruled out as the cause of magnetic properties. The techniques used to establish these were conventional and high-resolution transmission electron microscopy (HRTEM) along with electron-energy loss spectroscopy (EELS) and scanning transmission electron microscopy-atomic number (STEM-Z) contrast studies.
Characterizing gamma fields using isomeric activation ratios

Abstract Isomeric activities were induced in indium by gamma irradiation in three different gamma fields, through the reactions 115 In(γ, γ′) 115m In and 113 In(γ, γ′) 113m In. The irradiation fields were (i) the 15 kCi 60 Co source available in the University, (ii) the spent fuel gamma irradiator in the pool of the University's Ford Nuclear Reactor (FNR) and (iii) south face of the core of the FNR during routine shut downs. Isomeric activation ratios can serve to characterize gamma fields, provided the response functions of the two (γ, γ′) reactions sample different energy regimes of the gamma spectrum present in the irradiation fields. The response of an isomeric activation detector, in turn, depends on the number of activation energy levels of the nuclide and the probabilities with which the activation levels de-populate to the isomeric level. The reaction rate ratio R In115m / R In113m was measured in the three gamma fields. The measured ratios were (i) 1.210 ± 0.011 in the 60 Co source, (ii) 1.314 ± 0.060 in the spent fuel gamma irradiator and (iii) 1.298 ± 0.039 in a location alongside the FNR core during routine shut downs. The measured reaction rate ratios are not only close to each other, but close to unity as well. This indicates that the excitation functions for the reactions 115 In(γ, γ′) 115m In and 113 In(γ, γ′) 113m In have similar shapes and that for the nuclides 115 In and 113 In, the number of activation energy levels and the probabilities with which they populate the isomeric levels are very similar to each other. Thus, the ratio R In115m / R In113m will not yield any information regarding the shape of gamma spectrum in the field of measurement. However by choosing (γ, γ′) reactions with different shapes for the excitation functions one can measure a set of isomeric activation ratios that characterize a given gamma field.
Proton conduction in acceptor doped SnP2O7

Abstract Undoped and acceptor doped tin pyrophosphate with composition D 0.1 Sn 0.9 P 2 O 7 − δ (D = In, Ga, Zn, Sc, and Mg) were synthesized by the conventional solid state reaction method and sintered to obtain well densified pellets (> 90% relative density). The conductivity of all the synthesized materials was measured in unhumidified atmosphere in the temperature range 300 °C–600 °C using electrochemical impedance spectroscopy (EIS). The conductivity of acceptor doped SnP 2 O 7 was found to be significantly higher than undoped SnP 2 O 7 for all the dopants. Proton transference number measurements indicated that the charge transport in acceptor doped SnP 2 O 7 was mostly protonic. Within the dopants analyzed, Zn 0.1 Sn 0.9 P 2 O 7 − δ showed the highest conductivity of 2.84 × 10 −6 S/cm at 600 °C. This value is several orders of magnitude lower than previously reported for doped tin pyrophosphate compounds but it is consistent with a recent publication. The reason for the discrepancy was investigated and a possible explanation has been proposed based on results obtained from 31 P MAS–NMR spectroscopy as follows. It was observed that the as-calcined powder of doped SnP 2 O 7 contained a significant fraction of leftover phosphoric acid from synthesis procedure. This phosphoric acid is likely to be responsible for the high conductivity values for acceptor doped SnP 2 O 7 previously reported by other research groups.
Letter to the Editor---High-Level Operations Research Activity in the U.A.R.-Egyptian Region

In March of this year I visited the United Arab Republic-Egyptian Region, to look into mathematical and operations-research progress for the Office of Naval Research. I met several people in research, learned about their activity and gave lectures in operations research and mathematics both at the University of Cairo and at the National Planning Committee, which is in the ideal position of being able to examine problems arising on a national scale in Egypt.
Divergent GW182 functional domains in the regulation of translational silencing

MicroRNA (miRNA)-mediated gene regulation has become a major focus in many biological processes. GW182 and its long isoform TNGW1 are marker proteins of GW/P bodies and bind to Argonaute proteins of the RNA induced silencing complex. The goal of this study is to further define and distinguish the repression domain(s) in human GW182/TNGW1. Two non-overlapping regions, Δ12 (amino acids 896-1219) containing the Ago hook and Δ5 (amino acids 1670-1962) containing the RRM, both induced comparable silencing in a tethering assay. Mapping data showed that the RRM and its flanking sequences in Δ5, but not the Ago hook in Δ12, were important for silencing. Repression mediated by Δ5 or Δ12 was not differentially affected when known endogenous repressors RCK/p54, GW182/TNGW1, TNRC6B were depleted. Transfected Δ5, but not Δ12, enhanced Ago2-mediated repression in a tethering assay. Transfected Δ12, but not Δ5, released endogenous miRNA reporter silencing without affecting siRNA function. Alanine substitution showed that GW/WG motifs in Δ12 (Δ12a, amino acids 896-1045) were important for silencing activity. Although Δ12 appeared to bind PABPC1 more efficiently than Δ5, neither Δ5 nor Δ12 significantly enhanced reporter mRNA degradation. These different functional characteristics of Δ5 and Δ12 suggest that their roles are distinct, and possibly dynamic, in human GW182-mediated silencing.
Surface waves on a rotating fluid

Small-amplitude waves on the free surface of a liquid rotating at constant angular velocity about a vertical axis are studied analytically and experimentally In the experiments, surface waves are produced by mounting a rotating cylinder partially filled with water on a vibration table and oscillating the entire assembly vertically Subharmonic waves are found to occur as in the nonrotating case, but in the presence of rotation a larger forcing amplitude is required to produce instability A synchronous response, i e , at the forcing frequency, not present in the nonrotating case is also predicted and observed Depending on whether the surface wave frequency is greater or less than twice the rotational speed, the governing field equation is either elliptic or hyperbolic The elliptic case is similar to the nonrotating case, and the disturbance decays rapidly with depth In the hyperbolic case there is no decay of the motion with depth The results may be of interest in connection with sloshing in missile fuel tanks
Construction and characterization of Pichia pastoris strains for labeling aromatic amino acids in recombinant proteins.

Abstract Strains of the methylotrophic yeast Pichia pastoris auxotrophic for the aromatic amino acids (tyrosine, phenylalanine, and tryptophan) have been constructed by targeted gene disruption for protein labeling applications. Three strains, with defects in ARO1 (coding for a homolog of the arom pentafunctional enzyme), ARO7 (coding for chorismate mutase), and TYR1 (coding for prephenate dehydrogenase), have been engineered in a P. pastoris ura 3Δ1 parent strain using standard methods. The nutritional requirements of these auxotrophic strains have been characterized and their utility as expression hosts for labeling recombinant proteins has been demonstrated. All three strains show a surprising sensitivity to rich culture medium and must be grown in supplemented minimal medium. The tyr1 :: URA3 strain in particular is strongly inhibited by tryptophan, and to a lesser extent by phenylalanine, leucine, and isoleucine. Highly efficient incorporation of exogenously supplied amino acids by these three auxotroph strains has been demonstrated using recombinant galactose oxidase. Stereochemically pure l -amino acids and racemic d,l -mixtures serve nearly equally well to support protein expression and labeling. These strains allow efficient labeling of aromatic amino acids in recombinant proteins, supporting NMR structural biology and a wide range of other biophysical studies.
The ongoing challenge of retroperitoneal vascular injuries.

Background Retroperitoneal vascular injury remains one of the most frequent causes of death following abdominal trauma. A risk analysis of the association between potential outcome predictors and mortality following abdominal aorta and inferior vena cava injuries was performed. Methods Eighty-nine patients sustaining abdominal naortic or inferior vena cava injury were concurrently evaluated for a 10-year period and retrospectively reviewed. A multiple logistic regression model evaluated the following variables:presence of shock on admission, base def-icit ( Results Overall mortality for all injuries was 57%. Excluding all death on arrival (DOA) patients, the mortality rate decreased to 45.7%. Death following abdominal aortic injuries was significantly associated with free bleeding in the peritoneal cavity, acidosis, and an injury in the suprarenal location (OIS >4). For inferior vena cava injuries and combined abdominal aortic and inferior vena cava injuries, death was associated with free bleeding, the suprarenal location (OIS = 4), and the presence of shock on admission as well. Conclusions Despite advances in transport and resuscitation, mortality of aortic and vena cava injuries remains unchanged. Shock on admission, bleeding without retroperitoneal tamponade, acidosis, and the suprarenal location each play a significant role in mortality. Immediate identification associated with a rapid surgical approach are the only factors that may improve survival of such devastating injuries.
Characterization of neuronal regeneration in the abdominal ganglion of Aplysia californica

The ability of neurons in the abdominal ganglion of Aplysia to regenerate their axons following branchial nerve crush was studied using retrograde staining and intracellular dye injection. The duration of the gill withdrawal reflex (GWR) was measured prior to and following nerve crush. Three days after crushing the nerve, the duration of the gill withdrawal reflex was reduced to 20% of control levels. There was rapid recovery 19 days after crushing the branchial nerve. The GWR duration returned to control levels by postlesion days 25–27. Some of the behavioral recovery can be attributed to axonal regeneration. Regeneration, as evidenced by retrograde staining, was first observed by postlesion day 15. The number of stained neurons in ganglia with crushes increased until postlesion day 33. The number of stained neurons in experimental animals was always less than that of controls (67 ± 9% at postlesion day 56). More axonal regeneration was seen in the hemiganglion ipsilateral to the branchial nerve. Regeneration after 32 days postlesion was 60 ± 5% of controls in the ipsilateral hemiganglion, as opposed to 29 ± 6% in the contralateral hemiganglion. Regeneration of individual neurons was also demonstrated. Identified neuron R2 was shown by intracellular dye injection and electrical stimulation of antidromic action potentials to have an axon in the branchial nerve in all ganglia allowed to regenerate for longer than 32 days. These results indicate that in Aplysia, despite behavioral recovery, complete axonal regeneration does not occur in a large segment of the neurons in the adult central nervous system. © 1998 John Wiley & Sons, Inc. J Neurobiol 35: 160–172, 1998
Chromium in San Francisco Bay: superposition of geochemical processes causes complex spatial distributions of redox species

Abstract Processes controlling the geochemical cycle of Cr in San Francisco Bay were characterized with analyses of water samples taken from 25 stations distributed throughout the estuary. Mixing of water masses, localized inputs, in-situ reduction, and sediment resuspension contributed to complex spatial distributions of dissolved ( 3 days) for a particle reactive trace metal, suggesting either localized inputs or complexation by colloidal/organic matter. There was also a relative excess (2.6 nM) of Cr(VI) in another section of the Delta. Mass balance calculations showed that excess was the same order of magnitude as reported point source loadings of Cr in that area. The subsequent depletion of Cr(VI), along with a concurrent increase in Cr(III) concentration in a shallow region of the Delta, was tentatively attributed to in-situ reduction.
Dihydropteridine reductase in the rat brain

Abstract Dihydropteridine reductase has been detected in the rat brain. The enzyme is precipitated with a 45–70% ammonium sulfate saturation. The enzyme requires TPNH, a quinonoid form of dihydropterine and is not inhibited by 10 −5 M methotrexate. These properties are similar to those described for sheep liver and beef adrenal dihydropteridine reductase.
Effect of 6-mercaptopurine (6-MP) on the serum level of vitamin B12 in leukemia.

Abstract Vitamin B 12 determinations have been made on serum from patients suffering from leukemia or polycythemia vera. In chronic myelocytic leukemia, the B 12 content of the serum is approximately 16 times the normal. The results of serum vitamin B 12 determinations before and after 6-MP therapy in these patients indicate that a reduction in the total leucocyte count is gradually followed by a lowering of serum vitamin B 12 .
In Vitro Studies of DNA Damage Caused by Tricyclic Antidepressants: A Role of Peroxidase in the Side Effects of the Drugs

Studies show that tricyclic antidepressants prescribed for migraines, anxiety, and child enuresis have numerous adverse effects in living cells. One of the undesired outcomes observed under treatment with these drugs is DNA damage. However, the mechanisms underlying damage have yet to be elucidated. We performed in vitro studies of the DNA damage caused by four tricyclic antidepressants: imipramine, amitriptyline, opipramol, and protriptyline. We focused particularly on the DNA damage aided by peroxidases. As a model of a peroxidase, we used horseradish peroxidase (HRP). At pH 7, reactions of HRP with excess hydrogen peroxide and imipramine yielded an intense purple color and a broad absorption spectrum with the maximum intensity at 522 nm. Reactions performed between DNA and imipramine in the presence of H(2)O(2) and HRP resulted in the disappearance of the DNA band. In the case of the other three drugs, this effect was not observed. Extraction of the DNA from the reaction mixture indicated that DNA is degraded in the reaction between imipramine and H(2)O(2) catalyzed by HRP. The final product of imipramine oxidation was identified as iminodibenzyl. We hypothesize that the damage to DNA was caused by an imipramine reactive intermediate.