cssi/SciSciGPT-SciSciNet huggingface dataset:
Restricted rotation in amides. VII—methods of resonance assignment in tertiary amides—an evaluation†‡

Examination and evaluation of various methods for resonance assignments in amides reveals that only three of these are reliable: (a) the nuclear Overhauser effect, which leads to unequivocal results in tertiary amides; (b) the aromatic solvent induced shift, which is rapid and accurate for tertiary amides without polar substituents; (c) the lanthanide-induced shift, which although easy, can be applied only to tertiary amides with substituents that do not complex lanthanides.
Efficient optimal design space characterization methodologies

One of the primary advantages of a high-level synthesis system is its ability to explore the design space. This paper presents several methodologies for design space exploration that compute all optimal tradeoff points for the combined problem of scheduling, clock-length determination, and module selection. We discuss how each methodology takes advantage of the structure within the design space itself as well as the structure of, and interactions among, each of the three subproblems. (CAD)
Dynamics of the black–white gap in academic achievement

Abstract The black–white test score gap remains a measurable phenomenon in the United States. Up to this point the literature has primarily focused on the black–white achievement gap without taking into account the underlying mobility patterns of individual students as they progress from one grade to the next. However, the degree to which policy makers and educators should be concerned about the black–white test score gap should be tied to how mobile the two groups of students are through the distribution of test scores from one grade to the next. In this paper I apply two nonparametric estimators of distributional mobility to data on test scores and track black–white differences in mobility across the entire distribution of achievement. When compared to whites, blacks tend to be less upwardly mobile and more downwardly mobile for both math and reading. This pattern is particularly prominent for reading in the very early years of schooling.
Vitamin C requirement of the juvenile freshwater prawn, Macrobrachium rosenbergii

Abstract A quantitative dietary requirement of vitamin C has been determined for the juvenile freshwater prawn, Macrobrachium rosenbergii, using two water-stable sources of ascorbic acid, ascorbyl-2-monophosphate, calcium salt (AMP) and ascorbyl-6-palmitate (AP). Vitamin C was either not included or added to a semipurified diet at levels of vitamin C activity ranging from 10 to 200 mg/kg. A control diet contained 5000 mg of crystalline l -ascorbic acid/kg of diet. Mortality in vitamin-C-deficient diets (50 mg/kg) was observed within 21 days after initiation of two independent feeding trials conducted for 79 and 90 days and was generally associated with the lack of successful extrication from the old exoskeleton. Survival increased as the level of vitamin C activity increased from 0 to 100 mg/kg of diet. AMP and AP showed equimolar vitamin C activity. A quantitative requirement equivalent to 104 mg of vitamin C/kg of diet was estimated by a quadratic surface analysis, using survival as the measured response to the different dietary levels. This estimated requirement is one to two orders of magnitude lower than those determined for species of penaeid shrimp using dietary sources of ascorbic acid that are more water-soluble and less stable.
Estimation of heat sources in nuclear reactors

Knowledge of local heating rates is needed for estimation of operating temperatures, thermal stresses, and cooling requirements in nuclear reactor components. Heat is liberated by the dissipation of the energy of fission fragments, beta particles, fast neutrons, and gamma photons. Heating rates are formulated in terms of either neutron or gamma flux densities, the corresponding collision probabilities, and appropriate energy transfer coefficients, the forms of which are given. Special methods of estimating the flux densities are discussed. The data on the magnitudes of the various energy sources are reviewed.
Influence of plant growth substances and salicylic acid on flowering and growth in the Lemnaceae (duckweeds)

Abstract Results of both published and unpublished work are reviewed with respect to the influence of auxins, gibberellins, cytokinins, abscisic acid, ethylene, and salicylic acid on flowering and growth in the Lemnaceae. Most studies deal only with the effect of exogenously applied growth substances, and thus, the physiological significance of the observed effects is largely unknown.
Real-Time Scintigraphic Assessment of Intravenous Radium-223 Administration for Quality Control

Radium-223 (223Ra) dichloride is an approved intravenous radiotherapy for patients with osseous metastases from castration-resistant prostate cancer (CRPC). In addition to the therapeutic alpha radiation, there is additional 223Ra radiation generated which produces photons that can be imaged with conventional gamma cameras. No studies have evaluated real-time and quality imaging during intravenous 223Ra administration to verify systemic circulation and exclude 223Ra extravasation at the injection site. A retrospective review was performed for fifteen 223Ra administrations for CRPC patients which were imaged using a large field of view portable gamma camera (LFOVPGC) for the purposes of quality control and patient safety. Dynamic imaging of the chest was performed before, during, and after the 223Ra administration to verify systemic circulation, per institutional clinical protocol. Before and after 223Ra administration, a static image was obtained of the intravenous access site. Dynamic imaging of the chest confirmed systemic administration early during the 1-minute injection period for all patients. There were no cases of focal 223Ra extravasation at the site of intravenous access. These results verify that systemic 223Ra administrations can be quantified with real-time imaging using an LFOVPGC. This simple approach can confirm and quantify systemic circulation of 223Ra early during injection and exclude focal extravasation for the purposes of quality control.
Correlation between morphology and blood group-related antigen expression in pancreatic tumors induced in Syrian hamsters

Expression of blood group-related antigens (BGRAs) A, B, H, Le(b), Le(x) and Le(y) was examined immunohistochemically in neoplastic and hyperplastic lesions induced by N-nitrosobis(2-oxopropyl)amine in Syrian hamsters to determine a relationship between histological and biological patterns of the lesion and expression of BGRAs. With the exception of papillary ductal cell hyperplasia, A-antigen discriminated between the benign and malignant lesions far better than the other antigens, which showed heterogeneity in the expression of benign and malignant tumors. However, production of A-antigen decreased with the degree of tumor dedifferentiation and was absent in anaplastic regions of tumors. Marked differences were found in the expression of A- and B-antigen in tubular complexes, one of the earliest induced changes, in relation to the type of cells populating these lesions. Overall, B-antigen seemed to be associated more with benign cells than malignant cells. On the other hand, Le(x)-antigen was expressed primarily in the invasive portion of some cancers and seemed to reflect active proliferative processes.
Rapid calculations of vacuum wave numbers

In 1953 Edlen published a paper relating the refractivity of dry air to wavelengths in vacuum. His formula was recommended by the Joint Commission for Spectroscopy. In 1952 he published for the National Research Council of Canada Vacuum Corrections for Wavelengths from 2000 to 13500 A. The tables were useful in the calculations of vacuum wave numbers in ultraviolet and visible spectroscopy. However, in these days of programmable calculators the use of his tables is more cumbersome than need be and it is the purpose of this communication to show how the relationships he used can be adapted to the rapid calculations of vacuum wave numbers from wavelengths in air.
Accelerated Reliability Methodologies for Electronic Components: A Case Study

The procedures of estimating the time to failure from accelerated test data are reviewed in this study. An accelerated life test approach which provides the desired reliability results for a fiber optic sensor in shorter times than would be possible with a test performed under normal stress conditions is presented. Utilizing ReliaSoft ALTA software the statistical and life distribution that describe the time to failure of the sensor is determined and the desired reliability results are calculated using the level probability density function.Copyright © 2002 by ASME
Thermal tides in the atmosphere of Venus - Comparison of model results with observations

A linearized primitive equation (LPE) model is developed to study thermal tides in the atmosphere of Venus. The LPE model describes diurnal and semidiurnal oscillations of a cyclostrophically balanced atmosphere in which zonal velocity varies with altitude and latitude. The numerical algorithm follows Staniforth and Daley. The solar thermal forcing is increased algebraically in time to separate the forced tidal response from free atmospheric oscillations. Parameters of the basic state and forcing agree with Pioneer Venus observations. Results of the model are compared with the solar-fixed component of brightness temperature variations measured by Taylor et al. and Elson using data from the Pioneer Venus orbiter infrared radiometer (OIR). The comparison is made by convolving the computed model radiances with the weighting functions of the OIR channels. Agreement between LPE model results and OIR observations is excellent. Two interesting features of the OIR data are accounted for, namely, the slow variation of phase with altitude and the dominance of the semidiurnal oscillation over the diurnal oscillation. Success of the LPE model opens the way for calculating tidal transports of heat and momentum and assessing the role of tides in maintaining the Venus super-rotation.
A comparison of some spectrograms obtained with a Reticon and by coaddition of photographic plates

High-dispersion 2.4 A/mm spectra with signal-to-noise ratios of order 80 were obtained for three stars by using a Reticon detector and by coadding photographic spectrograms at the Dominion Astrophysical Observatory. Metal lines of equivalent widths 5 to 75 mA in Alpha Dra and Iota CrB show systematic differences of order 4 percent with an uncertainty of order 3 percent and an rms scatter of 2.0 to 3.7 mA about the mean equivalent-width differences.
Chemisorption of atomic hydrogen on Cu(111)

Abstract Angle resolved photoemission and thermal desorption studies of atomic hydrogen adsorbed onto the (111) surface of Cu show that the bonding of H to Cu is very similar to H bonding on transition metals. Saturated adsorption of atomic H at temperatures below 200K produces a two peak thermal desorption spectrum (peaks at ≈ 230K and ≈ 300K) and the photoemission spectra reveal a Hls derived bonding state ≈ 6.2 eV below the Fermi energy and quite dramatic charge redistributions within the Cu d-bands. Molecular H2 does not dissociate on the Cu(111) surface under the conditions of these experiments whereas atomic H chemisorbs even above room temperature. This confirms the existence of a large dissociation barrier on Cu.
The deep hot biosphere

There are strong indications that microbial life is widespread at depth in the crust of the Earth, just as such life has been identified in numerous ocean vents. This life is not dependent on solar energy and photosynthesis for its primary energy supply, and it is essentially independent of the surface circumstances. Its energy supply comes from chemical sources, due to fluids that migrate upward from deeper levels in the Earth. In mass and volume it may be comparable with all surface life. Such microbial life may account for the presence of biological molecules in all carbonaceous materials in the outer crust, and the inference that these materials must have derived from biological deposits accumulated at the surface is therefore not necessarily valid. Subsurface life may be widespread among the planetary bodies of our solar system, since many of them have equally suitable conditions below, while having totally inhospitable surfaces. One may even speculate that such life may be widely disseminated in the universe, since planetary type bodies with similar subsurface conditions may be common as solitary objects in space, as well as in other solar-type systems.
Two-dimensional fin with non-constant root temperature

Etude de l'influence de la temperature non constante de la base d'une ailette sur la perte de chaleur de l'ailette quand les coefficients de convection de toutes les surfaces ne sont pas egaux et quand le rayonnement thermique est neglige
Effects of preoptic – suprachiasmatic lesions on renal excretion of electrolytes

Abstract Rats sustaining lesions of the posteroventral portion of the medial preoptic nucleus and the anterior portion of the suprachiasmatic nucleus exhibited decreased cumulative urine volumes, as well as lower sodium and potassium excretion following hypertonic saline injections. Circadian rhythms and mean levels of these variables during the steady state were unchanged. The lesioned area may participate in central regulation of water and electrolyte balance.
The association between pain and depression and some determinants of depression for the general population of the United States.

ABSTRACTPain and depression are major reasons for pharmacotherapy, making the relationship between these two complaints important in defining optimal pharmacotherapy for both. Although the association between the two has been documented in the literature, most of the available work only focused on specific disease group or patients with certain type of pain. Whether the association exists for the general population is still an unsettled issue. The goal of this study was to examine the association between pain and depression and explore the some determinants of depression using national representative survey data for the general population in the United States. This work employed data from Medical Expenditure Panel Survey (MEPS) 2009, with people older than 18 were included in the study. Ordered logistic regression and generalized ordered logistic regression were performed while incorporating complex survey features. Estimation results suggested that depression and physical pain were positively associated....
Growth morphology of vicinal hillocks on the {101} face of KH2PO4: From step-flow to layer-by-layer growth.

The growth morphologies of vicinal hillocks on KH[sub 2]PO[sub 4][l brace]101[r brace] surfaces have been investigated using atomic force microscopy. Growth occurs on monomolecular steps both by step-flow and through layer-by-layer growth on both dislocation induced steps and 2D nuclei. Dislocation induced hillocks exhibit hollow cores. The circular cross sections of these cores are consistent with an isotropic step edge energy and the core radii are in good agreement with theoretical predictions. From the interisland spacing we estimate the surface diffusion length to be 200 to 300 nm at 300 K.
The effect of contextualized conversational feedback in a complex open-ended learning environment

Betty’s Brain is an open-ended learning environment in which students learn about science topics by teaching a virtual agent named Betty through the construction of a visual causal map that represents the relevant science phenomena. The task is complex, and success requires the use of metacognitive strategies that support knowledge acquisition, causal map construction, and progress monitoring. Previous research has established that middle school students struggle at such tasks without proper scaffolding and feedback. In Betty’s Brain, this feedback is provided by Betty and Mr. Davis, another virtual agent designed to provide guidance and suggestions as students work. This paper discusses our implementation of contextualized conversational (CC) feedback, and then presents the results of an experimental study exploring the effects of this feedback in two 8th-grade science classrooms. The results illustrate some advantages of the CC feedback in comparison with a baseline dialogue mechanism that presents similar strategies in a non-conversational, non-contextualized form. While both groups showed significant pre-to-post test learning gains, the difference in learning gains between the groups was not statistically significant. However, students who received CC feedback more often performed actions in accordance with the advised strategies, and they created higher quality causal maps.
Rationality and risk-taking in Russia’s first Chechen War: toward a theory of cognitive realism

This article seeks to establish a better scholarly understanding of former Russian President Boris Yeltsin’s decision to launch an ill-planned, risky, and ultimately disastrous invasion of the breakaway republic of Chechnya in 1994. Examining the decision-making environment that led up to the invasion, I conclude that while neorealism provides an adequate explanation for Yeltsin’s motives in this case, the decisions that he made in pursuit of these goals do not reflect the logic of rational utility maximization commonly associated with neorealist theory. Instead, I suggest that prospect theory – based on the idea that decision-makers tend to be risk averse when confronted with choices between gains while risk acceptant when confronted with losses – offers significantly more explanatory insight in this case. Thus, the article offers further support for an alternative theoretical approach to international relations that some scholars have termed ‘cognitive realism’, incorporating neorealist motives with a more empirically accurate perspective on the decision-making processes undertaken in pursuit of these motives.
Differential Adsorption of Phenol Derivatives onto a Polymeric Sorbent: A Combined Molecular Modeling and Experimental Study

Oxygenated aromatic compounds (OACs) are used for the synthesis of a variety of commercial products. Lignin from wood and other plant products are potential sources of OACs, but it is difficult to separate the mixtures of OACs found in digests of these raw materials. One promising separation approach involves the use of selective adsorption resins, such as the acrylic ester sorbent XAD-7. It has been shown previously that this sorbent binds the para isomer of one OAC, methoxyphenol, more favorably that the ortho isomer when hexane is used as the solvent. The present study uses a combination of molecular modeling and experiment to elucidate the mechanism of this selectivity. The calculations yield good agreement with experimental binding affinities and indicate that hydrogen bonding is the dominant mode of adsorption of para-methoxyphenol onto XAD-7 from hexane. In contrast, ortho-methoxyphenol appears to form an intramolecular hydrogen bond that weakens the intermolecular hydrogen bond to the sorbent. As ...
Inclusion: Considerations from social validity and Functional Outcome Analysis

Inclusion and particularly “full inclusion” has become a hotly debated topic. While proponents of inclusion believe that social, behavioral, academic, and developmental benefits occur for children with disabilities as well as for other, nondisabled, children in the classroom, research into inclusion provides equivocal results. This paper (a) describes inclusion, highlighting the inconsistencies in definitions and research; (b) discusses the importance of social validity in making inclusion decisions; and (c) presents an approach to inclusion using Functional Outcome Analysis (Noell & Gresham, 1993). While inclusion may be philosophically desirable, the research does not support its application as an all-inclusive approach. Inclusion decisions must be made on a case-by-case basis after a functional analysis of the student's behavior has been conducted.
Dependence of Moloney murine leukemia virus production on cell growth.

Abstract Production of Moloney murine leukemia virus (MuLV) ceases in cultures of infected mouse fibroblasts made stationary by growth in limiting medium. Stimulation of the cells to reenter the growth cycle synchronously was followed by two waves of virus release. The first wave, occurring within 4 hr after the cells were released from G 0 , was unaffected by 0.1 μg/ml of actinomycin D. The second wave, coinciding roughly with the mitotic period of the following cell cycle, was prevented by actinomycin D. Both waves of virus release were inhibited by 10 μg/ml of cycloheximide. The first wave of released virus appears to contain viral RNA already present in the resting cells, while the second wave of released virus particles carry newly formed viral RNA.
Coronary artery disease and prevention of heart failure

Coronary artery disease is a major contributor to the progression of left ventricular systolic dysfunction and heart failure (HF). Recognizing that coronary artery disease is a leading cause of HF in the United States is critical to reducing mortality resulting from this condition. Although some patients may be candidates for mechanical revascularization to improve left ventricular function, all patients are candidates for aggressive secondary prevention strategies. This review discusses the prevalence of coronary artery disease, prognostic significance and pathophysiology, risk factor modifications, pharmacologic treatments, and the role of revascularization.
An operator Newton method for the Stefan problem based on smoothing: a local perspective

Abstract The initial/Neumann boundary-value enthalpy formulation for the two-phase Stefan problem is regularized by smoothing. Known estimates predict a convergence rate of e 1 2 , and this result is extended in this paper to include the case of a (nonzero) residual in the regularized problem. A modified Newton Kantorovich framework is established, whereby the exact solution of the regularized problem is replaced by one Newton iteration. It is shown that a consistent theory requires measure-theoretic hypotheses on the starting guess and the Newton iterate, otherwise residual decrease is not expected. The circle closes in one spatial dimension, where it is shown that the residual decrease of Newton's method correlates precisely with the e 1 2 convergence theory.
Net tow and surface sediment distributions of pteropods in the South China Sea region: Comparison and oceanographic implications

Abstract The purpose of this work is to compare the sediment distributions of pteropod species and species groups with their known distributions in the plankton of the Southeast Asian region. Generally, the limits of net tow and sediment distributions of pteropod species on the Sunda Shelf and in the Java Sea are very similar, but there are several significant exceptions. Diacria quadridentata extends much farther into shallow water in Gulf of Thailand and Java Sea sediments than predicted from net tows. Although they were nearly absent from the Gulf of Thailand plankton, Creseis virgula virgula and C. virgula conica are present in upper-Gulf sediments. The occurrence of several oceanic pteropod species (and one oceanic planktonic foraminifer) in shallow-water sediments south of Singapore provides evidence that oceanic waters are at least occasionally transported through the Malacca Strait from the Andaman Sea toward Singapore. Hydrographic data and transport directions suggest that the occurrences of Clio convexa (a pteropod) and Euphausia sibogae (a euphausiid) only in the eastern South China Sea represent “spill over” from the Sulu Sea at the eastern end of their Indian Ocean distribution rather than preference for the eastern South China Sea environment. Karimata Strait between the southern South China Sea and the Java Sea seems to act as a filter for zooplankton species and apparently only the most tolerant shallow-water species communicate through the Strait.
Dynamical LEED study of C2H2 and C2H4 chemisorption on Pt(111): evidence for the ethylidyne group

Abstract We propose ethylidyne as the stable formed from C2H2 and C2H4 chemisorption on the Pt(111) surface (T ≈ 300–350 K). Consistent evidence to support this proposal is given by LEED intensity analysis and high resolution ELS studies of this species.
Further evidence for a time-independent shift of the focus of attention.

The separation between stimuli was manipulated in asame-different matching task. In Experiment 1, stimuli were upright Ts and/or Ls, whereas in Experiment 2, they were rotated Ts and/or Ls. In both experiments, mean reaction time (RT) for thesame-different judgment did not increase as a function of interletter separation, suggesting either that the time needed to relocate attention was independent of distance, or that the stimuli were processed in parallel. These alternatives were tested in a third experiment, with a diagnostic for parallel processing proposed by Egeth and Dagenbach (1991). The diagnostic indicated that the rotated Ts and Ls in Experiment 2 were processed serially. If serial processing implies the utilization of attention, then the results of Experiment 2 suggest that relocation of attention is time-invariant with respect to distance.
Photodetachment of molecular negative ions

Abstract In recent years, molecules with high electron affinities (≳ 3 eV) have drawn interest because of their potential applications in controlling electron densities in ionized gases. Previous experiments to determine the electron affinities of such molecules have been restricted to thermodynamic methods whose uncertainties are not easily established, and the results are often widespread. We have measured the electron affinity of WO 3 by determining the photodetachment threshold of WO − 3 . A fast beam (0.5–5 keV) of mass selected negative ions is merged with a coaxial laser beam, the laser frequency is varied and the photodetachment cross section near threshold is measured. The electron affinity of WO 3 was determined to be 3.33 +0.08 −0.15 eV. In addition, a lower limit of 3.7 eV was obtained for the electron affinity of HWO 4 . These results are compared with previous indirect measurements.
Empathic concern and helping behavior: Egoism or altruism?

Abstract The present experiment investigated whether empathic concern produces an egoistic motivation to reduce one's own distress or an altruistic motivation to reduce another person's distress. Subjects ( N = 120) were exposed to a person in distress and instructed either to observe the victim's reaction (personal distress) or to imagine the victim's feelings (empathic concern). In addition, half of the subjects were led to believe that their mood was temporarily fixed (i.e., unalterable), whereas the other half were led to believe that their moods were labile and, therefore, manageable. Ease of escape without helping (easy or difficult) was also manipulated. Consistent with previous work supporting the empathy-altruism model, subjects in easy escape/personal distress conditions (based on assignment to conditions and on an internal analysis) helped less than did subjects in the easy escape/empathic concern, difficult escape/personal distress, and difficult escape/empathic concern conditions. Beliefs about the lability of one's own mood did not significantly mediate the relationship between empathic concern and helping. These results suggest that, at least when helping is not personally costly, concern about another person's distress rather than about one's own emotional state, can be the primary motivation for helping.
Understanding the Role of Social Capital and School Structure on Latino Academic Success

This paper investigates the role of social capital and school structure on the academic success of Latino students. A review of the literature on previous explanations of Latino failure, research on academically successful Latinos, and the role of social capital and school structure on Latino academic success are investigated. The research shows that the way students are tracked in school plays an important role in gaining access to school agents and other academically successful peers. These relationships give access to social capital and increase college access. Implications for policy and practice are discussed. Many American schools in urban areas are made up largely of students who are defined by a variety of risk factors (Mehan et al., 1996). Yet despite the presence of multiple risk factors, not all students at urban public high schools do fail. There are thousands of students throughout these schools who despite their risk factors are able to achieve success similar to that of the most privileged. Are these students successful simply because they work harder than their peers? Are their peers failing because they chose not to study? Or is there something else contributing to these successes and failures that we are failing to notice? Recent research on academically successful minority youth has found that relationships with school personnel and college-bound peers can play an important role in the lives of students (Stanton-Salazar, 2001). In particular these relationships can serve as sources of information and support that provide the resources necessary for minority youth to achieve levels of academic success that are on par with the some of the most privileged members of society. Yet in order for these relationships to develop, minority youth must be in close contact with these individuals. Throughout the country, schools create structures that either allow or deny access to these individuals. It is through the structuring of programs and classes that youth are given the access to these institutional agents and high achieving peers who are so critical to college access for minority youth. Purpose The purpose of this paper is to provide a review of the literature on previous explanations for the academic failure of Latinos and why these explanations are unable to explain the academic success of some Latino students. In order to better understand Latino academic success, this paper will explore the role of social capital on the achievement of Latino students. 1 Gonzalez: The Role of Social Capital and School Structure on Latino Academic Success
Non-uniqueness in the one-dimensional inverse scattering problem

The Schrodinger equation in one dimension is considered for the case when at least one reflection amplitude at zero energy is unity. It is shown that if there exists a corresponding potential that causes no negative-energy bound states then there is a one-parameter family of potentials that causes the same scattering at all energies. Two explicit examples are given.
Electricity sector analysis in the clean energy futures study

Abstract This paper examines the impact of policies to reduce carbon and other air emissions in the electric sector. The analysis is from a recent scenario development effort, Scenarios for a Clean Energy Future (CEF), by five National Laboratories. The CEF assesses how policies can be used to promote energy-efficient and clean energy technologies to address key energy and environmental challenges facing the United States. The impact of policies in the electric sector is evaluated using the CEF-NEMS model, which is derived from the National Energy Modeling System (NEMS) model developed by the DOE Energy Information Administration. The analysis shows that by 2020 under the policies analyzed, CO2 and other emissions can be substantially reduced by moving from coal to advanced gas combined cycle systems and renewable energy. Prices show little change and may drop due to decreased end-use demands.
Performance of NEG getter materialin a sealed reflex-triode vircator at 225 A/cm 2

Summary form only given. This study focuses on the use of non-evaporable getter (NEG) materials in a high power microwave (HPM) virtual-cathode oscillator (vircator). The vircator has a background pressure in the low 10-9 torr range with a vacuum volume of 5 L backed by a small 20 L/s ion pump. Presently, the source is driven by an 80 J, 300 kV Marx generator with a current density of 225 A/cm2 and pulse width of 100 ns. Initial current pulses increases the chamber pressure to the low 10-6 torr range desorbing approximately 1014 particles1,2. Reduction in the number of particles desorbed decreases an order of magnitude after approximately 2,000 current pulses, with no further noticeable decrease after 10,000 pulses3. The HPM system will eventually be modified to operate at 500 Hz with a pulse width between 10-20 ns. In first order approximations, a pumping speed of 2500 L/s will be needed to pump 1014 particles within 2 ms from a 5 L volume. This corresponds to a surface area of approximately 2400 cm2 for a zirconium-vanadium-iron (ZrVFe) getter material. An introduction of NEG materials into the vacuum chamber will aid in achieving repetitive operation; and preliminary results on the use of the NEG material in the vacuum environment will be presented. A residual gas analyzer (RGA) and an inverted-magnetron cold cathode vacuum sensor are used for the gas diagnostics and are rated to survive the 300°C, 72 hour vircator bake out process.
Some determinants of drug responsiveness in bovine leukemia cells.

Abstract Buffy coat cells derived from a cow with lymphosarcoma and grown in culture were studied and levels of enzymes involved in metabolism of selected antitumor agents measured. The data are in general agreement with other results obtained using freshly isolated bovine leukemic cells of diverse origin. These data suggest that the bovine leukemias, unlike leukemia in man, have a marked biochemical uniformity. Our results suggest that bovine leukemic cells are considerably more sensitive to fluorouracil, and considerably less to cytosine arabinoside than the 35 similarly derived human leukemic cell types. The bovine leukemic cells contain high levels of a pyrimidine-5' phosphoribosyltransferase involved in fluorouracil anabolism, and low levels of deoxycytidine kinase, the first enzyme on the pathway of conversion of cytosine arabinoside to the pharmacologically active form.
Applied numerical methods and graphical visualization

In this article, we describe an interactive, MATLAB-based, platform-independent, educational tool which integrates numerical methods for solving problems ranging from linear algebraic systems to partial differential systems with a graphical user interface. For modularity, the tool is divided into three blocks: 1 a collection of numerical methods, which constitutes the core of the package; 2 a series of examples, problems, and figures, which contributes to the understanding of the applicability of the numerical techniques implemented in the package; and 3 a graphics user interface, which integrates the methods and examples into MATLAB's graphical environment. The numerical methods range in complexity from elementary applications to more complex examples representative of engineering problems of interest. A help facility assists the user with the program features. Sample problems are presented to demonstrate the utility of the program as an educational tool and as a vehicle for introducing students to new numerical concepts and their graphical visualization. © 1996 John Wiley & Sons, Inc.
Optical system properties of a reconfigurable MEMS interconnect

The optical system properties of a reconfigurable surface micromachined micro-electro-mechanical system (MEMS) interconnect are presented. An array of optical signals from a singlemode MT connector is first collimated by a refractive lenslet array. Each beam may be individually redirected by a rotatable, 45 degree flip-up MEMS mirror. The second, complimentary MEMS mirror folds the optical beam back through the lenslet array and couples it into a second fiber row on the MT connector. Much work has been presented promoting the utility of MEMS configurations to manipulate optical signals. This work examines, with ray tracing simulations, the proposed configuration from the detailed optical system perspective.
Investigation of the elastic properties of the particle network in gelled solutions of hydrocolloids. I. Carboxymethyl cellulose

In order to obtain information on the structure of the particle network existing in gelled solutions of carboxymethyl cellulose, the elastic modulus was determined of series of dilutions of three samples of different molecular weight. It was found that these results could be accounted for reasonably well with the assumptions (1) that the crosslinking of molecules can be described as a reversible bimolecular aggregation between surface sites, (2) that the network formed may be described by Flory's theory of gelation and (3) that the network is deformed according to the theory of rubber elasticity.
Maternal nutrition and hydrocephalus in newborn rats.

SummaryFemale rats were supplied with an experimental diet that contained soybean oil meal as a source of protein, and a vitamin mixture that included all recognized vitamins except ascorbic acid, niacin, folic acid and B12. The incidence of hydrocephalus in the young was less than 1%. When folic acid antagonist was added to this diet the incidence of hydrocephalus rose to 20%. The type of diet consumed during the pre-experi-mental period determined the amount of time that elapsed, during the experimental period, before hydrocephalus appeared in the young.
DMSO Complexes of Trivalent Metal Ions: First Microsolvated Trications Outside of Group 3

The advent of electrospray ionization source opened the door to generation of multiply charged metal ions complexed with organic molecules. A significant amount of work on ligated dications has appeared over the past decade. In contrast, only several microsolvated tripositive ions have been reported, involving solely the few rare earths with the lowest third ionization energies (IEs) of all elements (<23 eV). Here trications of numerous trivalent metals outside of group 3 are shown to coordinate dimethyl sulfoxide (DMSO), an eminent aprotic solvent. These include both main group elements (Al, Ga, In, Bi) and transition metals (V, Fe, Cr) with the third IE up to 31 eV, which is 22 eV above the IE of DMSO. Fragmentation of M3+(DMSO)n for these metals (plus La, Yb, and Sc) has been characterized in detail using collision-induced dissociation (CID). A rich, highly element specific dissociation chemistry is observed, including the homolytic C−S cleavage in (+3) charge state and various charge-reduction process...
The relation between the caliber of the axon and the trophic activity of nerves in limb regeneration.

Previous work from this laboratory demonstrated a relation between ability to regenerate a limb and number of nerve fibers available per unit area of amputation wound. Animals with fewer fibers than the newt, Triturus, (for example, Rana, Anolis, and Mus) do not regrow the limb. An exception appeared in Xenopus whose limb is sparsely innervated and yet which regenerates. The present work demonstrates that the nerve fibers of Xenopus make up in individual size what they lack in number. When the average cross-sectional area of the axons was multiplied by the number of fibers per unit area, the results showed that the Xenopus limb is about as well supplied with axoplasm as that of Triturus. This was not true for Rana. The results also demonstrate for the first time a direct relation between caliber and trophic effectiveness of the axon, the evolutionary significance of which is discussed.
Safety and potential cost savings of same-setting electrophysiologic testing and placement of transvenous implantable cardioverter-defibrillators.

Background: Separately, electrophysiologic study (EPS) and placement of a transvenous implantable cardioverter-defibrillator (ICD) can be performed safely in the majority of patients. The safety and potential cost savings of same-setting procedures have not been evaluated. Hypothesis: Electrophysiologic study and placement of transvenous ICDs can be performed safely in the same setting at reduced cost. Methods: in all, 160 (mean age 65 ± 10 years, 75% men) and 41 (mean age 66 ± 11 years, 73% men) consecutive patients who underwent same- versus separate-setting procedures, respectively, were prospectively evaluated. Results: The two groups had similar clinical characteristics and indications for EPS and ICD therapy. Complications occurred in eight patients (5.0%, 95% confidence interval [CI] 2.3–10.3) who had same-setting procedures (one hypotension during ICD testing, one pocket hematoma, two lead dislodgments, two pneumothoraces, one stroke, and one infection) and in two (4.9%, CI 0.60–16.5) who had separate-setting procedures (one pocket hematoma and one infection). There were no procedure-related deaths or long-term ICD-related complications in either group. The mean time from ICD implantation to hospital discharge was similar in the two groups (2.5 ± 2.4 vs. 2.7 ± 2.2 days, p = NS). The combined procedure cost was higher in patients who had separate-setting procedures ($12,403 ± 1,386 vs. $10,242 ± 2,256, p = < 0.001), who incurred an additional hospital cost of $2,121 ± $2,125 for the waiting period (1.7 ± 1.6 days) between EPS and ICD implantation. Conclusions: in patients deemed candidates for ICD therapy based on EPS results, placement of transvenous defibrillators in the same setting as EPS is as safe as separate-setting procedures and, if adopted, could further reduce the cost of providing ICD therapy.
Relationships between duration and temporal variability in children's speech.

Various studies of speech production development have observed that duration and temporal variability tend to decrease as children get older. Because both of these factors are commonly viewed as general indicators of neuromotor maturation of children’s speech skills, it would seem reasonable to assume that they should be rather closely correlated with one another. However, an examination of a variety of temporal data from children ranging between approximately 2 (1)/(2) and 9 (1)/(2) years of age indicates that there is not necessarily as close a correspondence between these two variables as might be expected. It also appears that children’s duration measures tend to be more adultlike than measures of their intrasubject variability.
Some new results on Unsymmetric Successive Overrelaxation method

The Unsymmetric Successive Overrelaxation (USSOR) iterative method is applied to the solution of the system of linear equationsA x=b, whereA is annxn nonsingular matrix. We find the values of the relaxation parameters ? and $$\bar \omega $$ for which the USSOR iterative method converges. Then we characterize those matrices which are equimodular toA and for which the USSOR iterative method converges.
Sum-rule moment bounds on long-range van der waals potentials

Abstract Quantum-mechanical sum rules and results from the theory of moments are employed in the construction of rigorous bounds on the long range van der Waals interactions of atoms and molecules.
Dry-matter partitioning in loblolly and slash pine: Effects of fertilization and irrigation

Abstract The effects of fertilization and irrigation, singly and in combination, on growth and dry-matter allocation in seedlings of Pinus taeda and P. elliottii were investigated under field conditions. Trickle irrigation was regulated to maintain soil water potential above −10 kPa and 111 g of fertilizer (N:P:K 10:10:10 plus micronutrients) were banded around each seedling on three occasions. Treatments were initiated at the beginning of the second growing-season in the field, the same year sampling was conducted. Sampling consisted of complete excavation of 15 seedlings per treatment per species beginning in early April and continued every 6 weeks through mid-November, 1986. Each seedling was measured for height, root-collar diameter, foliage, stem and root dry-matter, and total needle surface-area. Allometric growth-analysis was used to determine dry-matter partitioning among the various tree components. The cultural treatments affected the two species differently. Loblolly pine responded to treatments by shifting dry-matter allocation from roots to shoots, with the greatest increase observed in the fertilization treatment. Slash pine showed a similar response to irrigation and to irrigation plus fertilization, but increased allocation to roots under the fertilization treatment. Allocation to stems was greater than to foliage in both species and treatments except the control loblolly pine.
Early indications of monocrotaline pyrrole-induced lung injury in rats

Monocrotaline pyrrole (MCTP), a putative metabolite of the naturally occurring plant toxin, monocrotaline (MCT), causes lung injury, pulmonary hypertension, and right cardioventricular hypertrophy when administered intravenously to rats. The lesions caused by MCTP administration are similar to those caused by MCT but appear to occur on a slightly accelerated time course. To explore the onset and development of lung lesions, male Sprague-Dawley rats were treated with a single, intravenous injection of MCTP, and several markers of lung injury were evaluated at early times after administration. Rats received 3.5 mg MCTP/kg or an equal volume of the vehicle, N,N-dimethylformamide (DMF), via the tail vein at time 0 and were killed at 4, 12, 24, 48, 72, or 120 hr after treatment. Beginning at 4 hr, MCTP-treated rats had increased wet lung-to-body-weight ratios (LW/BW). The LW/BW remained elevated at 12 hr, returned to baseline at 24 hr, then increased steadily over the next few days. At 24 hr, the protein concentration of cell-free bronchoalveolar lavage fluid (BALF) was slightly elevated. Lactate dehydrogenase activity in cell-free BALF samples was moderately increased 48 hr after MCTP. Changes in these markers were modest initially but became much more pronounced by 120 hr. Total nucleated cell counts in BALF were variable but were moderately elevated at 120 hr. Cytologic examination of the BALF samples revealed small but significant infiltrates of segmented neutrophils at 4 hr and relatively large infiltrates of segmented neutrophils and small lymphocytes at 120 hr post-treatment. Mature neutrophils had degenerate cytomorphologic characteristics at both 4 and 120 hr. These results confirm that pronounced lung injury is delayed for several days after a single, intravenous administration of MCTP, but they also indicate that subtle lung injury can be detected using quantitative markers quite early after MCTP administration.
Correlation of characteristics of gel extrusion module (GEM) tablet formulation and drug dissolution rate

The purpose of the study was to characterize the swelling properties of controlled release tablet formulations with compositional and processing differences. A correlation was also established between the drug dissolution rate from the controlled release gel extrusion module (GEM) tablet and the swelling properties of the core tablet. The GEM tablet consisted of a core tablet of water swellable Carbopol polymer, a neutralizing agent, drug, and excipients. The tablet was subsequently coated with a rigid, water impermeable membrane. A number of holes were then drilled by laser through the impermeable membrane. Dynamic mechanical analysis (DMA), Perkin Elmer DMA7, was used to characterize the swelling properties. During the swelling measurements, the measuring probe and sample were completely submerged in the surrounding medium. The results showed that the formulation containing potassium phosphate dibasic as a neutralizing agent had the highest swelling rate. Correspondingly, this formulation had the highest drug dissolution rate over the same time period. The processing difference included wet granulation and dry roller compaction. The compositional differences included different neutralizing agents, binders or Carbopol polymers. The results showed a linear relationship (r(2)=0.954) between the swelling rates of the core tablets and the drug dissolution rates of GEM tablets. No correlation was found between the drug dissolution rates and either the maximum extent of tablet swelling or the time needed to reach the maximum extent of swelling. The results demonstrated that DMA could be used to support both formulation and process development to determine the effects of different compositions and manufacturing processes on drug dissolution rates for swelling controlled release devices.