cssi/SciSciGPT-SciSciNet huggingface dataset:
Epidemiology of human immunodeficiency virus-associated pulmonary disease.

Abstract HIV/AIDS was initially characterized as a progressively worsening disorder of cellular immunosuppression. In 1996, HIV/AIDS was separated into 2 diagnostic, management, prognostic categories: high-income and low-income groups. High-income people with HIV have had access to antiretroviral therapeutic agents, which have transformed HIV from a lethal to an indolent disease, with life expectancy comparable with other chronic conditions. About 50% of low-income people with HIV who are candidates for antiretroviral therapy actually receive it. Since 1996, the principal HIV-associated pulmonary disease in high-income countries has changed from Pneumocystis pneumonia to community-acquired pneumonia; tuberculosis has predominated in low-income countries as long as HIV has prevailed.
Viscoelastic characterization of concentrated polyaniline solutions: New insights into conductive polymer processing

Abstract The processing of conductive polymers has been limited by insolubility and gelation. Concentrated polyaniline solutions have been prepared in DMPII facilitating processing into continuous fibers. However, the stability of these solutions is sensitive to concentration and time. Therefore, an understanding of the viscoelastic behavior of these solutions is critical for high quality fibers to be spun in large quantities. Characterization of dynamic rheological properties provides new insight into the processability of polyaniline.
Optimum Stirling engine geometry

This paper combines the author's work on mechanical efficiency of reciprocating engines with the classic Schmidt thermodynamic model for Stirling engines and revisits the problem of identifying optimal engine geometry. All previous optimizations using the Schmidt theory focused on obtaining a maximal specific indicated cyclic work. This does not necessarily produce the highest shaft output. Indeed, some optima based upon indicated work would yield engines that cannot run at all due to excessive intrinsic mechanical losses. The analysis presented in this paper shows how to optimize for shaft or brake work output. Specifically, it presents solutions to the problem of finding the piston-to-displacer swept volume ratio and phase angle which will give the maximum brake output for a given total swept volume, given temperature extremes, a given mean operating pressure, and a given engine mechanism effectiveness. The paper covers the split-cylinder or gamma-type Stirling in detail, serving as a model for similar analysis of the other Stirling engine configurations. Copyright © 2002 John Wiley & Sons, Ltd.
Synthesis and characterization of novel toughened thermosets derived from pendent amines on the backbone of poly(arylene ether sulphone)s

Random incorporation of pendent aryl amines on the backbone of poly(arylene ether sulphone)s was achieved by the copolymerization of a minor amount of bis(4-fluorophenyl)-3-aminophenylphosphine oxide with 4,4'-dichlorodiphenylsulphone and bisphenol A via aromatic nucleophilic substitution polymerization. The pendent amines were optionally chemically modified by conversion to maleimides and thermally cured to afford tough insoluble networks. Epoxy networks were also obtained by reacting the pendent amines with liquid epoxy resin and 4,4'-diaminodiphenysulphone. It was shown that selected compositions could significantly improve the fracture toughness of the epoxy networks
Nucleocytoplasmic RNA transport.

A number of closely related post-transcriptional facets of RNA metabolism show nuclear compartmentation, including capping, methylation, splicing reactions, and packaging in ribonucleoprotein particles (RNP). These nuclear ‘processing’ events are followed by the translocation of the finished product across the nuclear envelope. Due to the inherent complexity of these interrelated events,in vitro systems have been designed to examine the processes separately, particularly so with regard to translocation.
Using a genetic algorithm to predict evaluation of acute coronary syndromes.

Background: Because rapid therapy can improve the unfavorable prognosis of individuals with acute coronary syndromes (ACSs), it is critical that nurses accurately as)) sociate the cues of ACS and quickly and aggressively initiate interventional strategies that reduce mortality. Objectives: To determine if genetic algorithms (GAs) can be used to decipher the prediction rules that emergency department (ED) nurses use to triage persons suspected of having ACS and to determine whether these rules differ based on patient gender. Methods: A nonexperimental, descriptive study was conducted. Three thousand ED nurses were selected randomly to receive a mailed clinical vignette questionnaire, and 840 questionnaires were returned. Data analysis included binary logistic regression (BLR), development of GA, sensitivity, specificity, receiver-operator characteristic curves, and Monte Carlo simulations. Results: Nurses use different prediction rules for triaging male and female vignette patients with possible ACS. Accuracies were similar between BLR and GA. Both suffered a loss of predictive accuracy when algorithms or equations developed on one sex were tested on the other sex. Monte Carlo simulations showed that similar cues were used in triaging both men and women but they were combined differently in producing GA. Discussion: Using GA was as accurate as results found by BLR and can be used to predict nurses triage decisions for ACS. The GA presented as flow charts may be user-friendly.
Phospholipid changes in the bones of the hypophosphatemic mouse

The mineral and lipid composition of the bones of 35 day old hypophosphatemic (Hyp/Y) and control (+/Y) mice were compared in order to test the hypothesis that phosphate status has an effect on the complexed acidic phospholipid content of developing bones. The Hyp/Y bones were found to be rachitic and osteomalacic, having significantly reduced mineral content. That mineral was shown by X-ray diffraction to consist of larger/more perfect crystals than that in +/Y animals, indicating either a preference for crystal growth rather than new mineral deposition, or an increased mineral turnover. The increased crystal perfection was confirmed by chemical analyses which showed an increased calcium to phosphorus ratio in the Hyp/Y bones. The bones of Hyp/Y animals had significantly reduced complexed acidic phospholipid contents relative to those of control animals. Since these complexes are believed to play a role in vitro and in vivo mineral deposition, it is suggested that the deficiency of these complexes contributes to the mineralization defect. The magnitude of the complexed acidic phospholipid deficiency in the Hyp/Y animals indicates the importance of phosphate for the formation of these lipids. Although the proportion of phosphatidylserine and phosphatidylinositol and lysophospholipids tended to be reduced in the Hyp/Y bones, the absence of other statistically significant phospholipid abnormalities in the bones and brains of these animals suggests that the lipid defect is not systemic, but is associated with a decrease in phosphate at the site of bone formation.
Radiation induced ionic polymerisation and grafting of vinyl monomers

Some special aspects of the radiation induced ionic polymerisation and grafting of vinyl monomers will be described. In particular the effects of solvents on the cationic polymerisation of the vinyl ethers will be discussed in detail. The unequivocal free ion nature of the polymerisation makes such information of considerable general interest. Estimates of the propagation rate constants with free cation polymerisation in solvents of different dietectric constants and solvation powers will be presented. Finally, some observations on the radiation induced graft polymerisation of ethyl vinyl ether to poly (vinyl chloride) and to polypropylene will be presented.
Variational calculations of scattering

Abstract It has been found that the behavior of calculated results using variational principles for scattering problems is rather different from that previously known for bound-state problems. As more and more adjustable terms are added to the trial function, the “stationary” value for the phase shift does not converge smoothly, but may on occasion turn out to be grossly inaccurate. In this paper the phenomenon is displayed and partially analyzed, but not completely understood. We seem to be stuck with the conclusion that for a given amount of computational labor, a scattering phase shift may be determined only to an accuracy an order of magnitude worse than that of the analogous eigenvalue problem.
The role of air in oil agglomeration of coal at a moderate shear rate

Abstract The agglomeration of an aqueous suspension of highly hydrophobic coal particles with heptane or hexadecane was investigated with a laboratory mixing unit equipped with a flat-blade, turbine agitator which produced a moderate shear rate. The ground sample of coal from the No. 2 gas seam in West Virginia was subjected to agglomeration conditions both with and without air present in the closed mixing unit. Although compact, nearly spherical agglomerates were produced both in the presence and absence of air, the rate of agglomeration was much greater, and larger agglomerates were produced with a given amount of oil when air was present. Having air present also improved product quality and recovery. The effect of air was greater with smaller amounts of oil than with larger amounts.
Janus Scorpionates: Supramolecular Tectons for the Directed Assembly of Hard -Soft Alkali Metallopolymer Chains

A new scorpionate ligand [HB(mtda)3-] containing mercaptothiadiazolyl (mtda) heterocyclic rings with both hard nitrogen donors and soft sulfur donors has been prepared. This new ligand, the Janus scorpionate, is a hybrid of a tris(pyrazolyl)borate and a tris(mercaptoimidazolyl)borate. The differential hard/soft character of the dissimilar donor groups in this bridging ligand was exploited for the controlled solid-state organization of homometallic and heterometallic alkali metal coordination polymers. Remarkably, in the case of sodium, coordination polymers with both acentric (with NaS3N3H kernels) and centric (with alternating NaN6 and NaS6H2 kernels) chains are found in the same crystal (where the centricity is defined by the relative orientations of the B−H bonds of the ligands along the lattice). For the homometallic potassium congener, the larger cation size, compared to sodium, induced significant distortions and favored a polar arrangement of ligands in the resulting coordination polymer chain. An ...
The transition from stage I to stage II fatigue crack propagation in copper single crystals cycled at constant strain amplitudes

Abstract Stage I crack propagation has been studied in smooth specimens of copper single crystals cycled at strain amplitudes corresponding to the plateau of the cyclic stress-strain curve. The transition from stage I to stage II propagation received special attention with respect to crystal orientation. We have observed that the transition is accompanied by slip on the secondary slip system and the maximum stage I crack length decreases drastically for orientations in which the shear stress on the secondary system more closely approaches that on the primary system. A theory for the transition is offered, based on the postulate that stage II propagation occurs at a stage I crack when work hardening at the tip of the crack in the primary persistent slip band (PSB) raises the resolved shear stress locally acting on the secondary slip system to that required to initiate a PSB in that system. Reasonable agreement between calculated and measured values of the stage I crack length at transition to stage II encourages us that the approach used here is sound.
Latency and temporal overlap of visually elicited contralateral and ipsilateral firing in Xenopus tectum during and after the critical period.

Abstract The mechanisms underlying the development of proper topographic registration of binocular maps in the tectum of Xenopus laevis involve correlation of activity patterns of ipsilateral and contralateral inputs. Recent evidence implicates NMDA-type glutamate receptors in this process. In general, NMDA receptors are considered to function optimally when there are multiple, simultaneous excitatory inputs to a dendrite. In the binocular system of the frog, however, the ipsilateral eye's response to a visual stimulus reaches the tectum later than the contralateral eye's response. The reason for this delay is that the ipsilateral pathway to the tectum is indirect, involving a relay in the opposite tectum and nucleus isthmi. In this paper, we evaluate the duration of the delay between arrival of contralateral and ipsilateral input in response to cessation of light and we also gauge the extent of temporal overlap in responses of the two inputs. We find that the average delay is about 10 ms and that this delay is not significantly different during the critical period vs later in development. The temporal overlap is 40–60 ms in duration. We conclude that the intertectal delay does not prevent a substantial period of simultaneous firing of ipsilateral and contralateral inputs in response to sudden changes in illumination. Therefore, the firing patterns of these afferents are compatible with a mechanism of activity-dependent alignment of binocular maps in the tectum.
3-D flow visualization of axisymmetric jets at Reynolds number 6,700 and 10,200

A recently developed 3-D flow visualization system is used to capture instantaneous 3-D images in the near-field of an axisymmetric jet at Reynolds number 6,700 and 10,200. The 3-D images, which are acquired through the scanning of a pulsed MHz-rate laser sheet, have spatial resolution of up to 312 × 260 × 100 voxels and time resolution of 100 μs, producing effectively instantaneous, high-resolution 3-D images of the jet. These images represent the first truly volumetric flow visualization images to be captured in the near-field of a jet over this range of Reynolds numbers. The images show the formation of large-scale axisymmetric vortex rings along with the formation of counter-rotating streamwise vortex pairs that surround the periphery of the jet in a periodic manner and co-exist with the ring vortices. The azimuthal frequency of the streamwise vortices increases with Reynolds number from 10 to 14 structures around the circumference at Re = 6,700 to 18–22 structures at Re = 10,200. In some instances, the streamwise vortices are observed to maintain their phase and span across several vortex rings in the streamwise direction. In other instances, however, the streamwise vortices display abrupt changes in the downstream direction. The images also display a complex interaction between the vortex rings and streamwise structures in the transition region near the end of the potential core illustrating the importance of the streamwise vortices on the evolution of the jet flow.
A high gain photonic band gap gyrotron amplifier

A gyrotron amplifier that uses a novel photonic band gap (PBG) interaction circuit has achieved a peak small signal gain of 38 dB at 247.7 GHz, 32 kV and 0.35 A. The instantaneous -3 dB bandwidth of the amplifier at peak gain is 0.4 GHz. A peak output power of 45 W has been measured. The output power is not saturated but is limited by the 7.5 mW of available input power; the saturated output power is believed to be of order 500W. The PBG interaction circuit that confines the TE03-like mode for operation and provides stability from oscillations in lower order modes. The amplifier can be tuned for operation from 245-255 GHz. Experimental results taken over a wide range of parameters, 15-30 kV and 0.25-0.5 A, show good agreement with a theoretical model that incorporates cold test measurements for the transmission line, input coupler, PBG waveguide and mode converter.
Dynamic characterization of aortic annulus geometry and morphology with multimodality imaging: predictive value for aortic regurgitation after transcatheter aortic valve replacement.

Background Patients undergoing transcatheter aortic valve replacement (TAVR), as compared with those undergoing surgical aortic valve replacement (AVR), have higher postprocedural aortic regurgitation (AR), associated with higher mortality. We hypothesized that reduced annular deformation is associated with higher postprocedural AR and sought to assess incremental value of assessment of aortic annular deformation in prediction of post-TAVR AR. Methods We included 87 patients with high-risk severe aortic stenosis (AS) (81 ± 10 years, 54% men) who underwent preprocedural echocardiography and contrast-enhanced (4-dimensional) multidetector computed tomography (MDCT) of the aortic root, followed by TAVR (n = 55) or surgical AVR (n = 32). On MDCT, minimal/maximal annular circumference, circumferential deformation (maximum-minimum over cardiac cycle), and eccentricity (largest/smallest diameter during systole) were calculated. Degree of commissural/annular calcification was graded semiquantitatively (scale 1-3). Oversizing/undersizing of the prosthesis during TAVR was assessed. Results Pre-AVR aortic valve area (0.6 ± 0.1 vs 0.6 ± 0.1 cm 2 ), mean aortic valve gradient (46 ± 14 vs 45 ± 11 mm Hg), AR (1 ± 0.8 vs 0.9 ± 0.7), maximal annular circumference (8 ± 1 vs 7.9 ± 0.8 cm), annular deformation (0.3 ± 0.1 vs 0.3 ± 0.1 cm), eccentricity (1.2 ± 0.1 vs 1.2 ± 0.1), commissural (2.1 ± 0.6 vs 2 ± 0.7), and annular calcification scores (1.7 ± 0.8 vs 1.7 ± 0.8) were similar in TAVR and surgical AVR groups ( P = not significant). A higher proportion of patients had ≥ mild AR in the TAVR than in the surgical AVR group (58% vs 34%; P P = .01) predicted postprocedural AR, in addition to prosthesis undersizing ( P = .03) and higher annular calcification ( P = .03). Conclusions Residual post-TAVR AR is predicted by reduced aortic annular deformity, higher annular calcification, and prosthesis undersizing. Pre-TAVR 4-dimensional annular assessment aids in prediction of post-TAVR AR.
High performance YBCO films by the hybrid of non-fluorine yttrium and copper salts with Ba–TFA

Abstract High performance YBCO films have been fabricated using a metallorganic deposition (MOD) approach consisting of a hybrid of Ba–trifluoroacetate (Ba–TFA) with non-fluorine containing Cu and Y solution precursors on rolling-assisted-biaxially-textured substrates (RABiTS). A high J c of 2.4 MA/cm 2 at 77 K for 0.6 μm YBCO films on RABiTS corresponding to an I c over 140 A/cm-w was obtained. T c measurements showed sharp transitions with zero resistance above 90 K. Extrapolation of the normal state resistivity results in an intercept below zero at 0 K, indicating the absence of second phases at grain boundaries. This first report on obtaining high J c with significantly reduced fluorine in the precursor is important for scale-up to manufacturing since the volume of corrosive hydrofluoric gas (HF), which is a by-product of the conversion, is greatly reduced.
Analyzing locality of memory references in GPU architectures

In this paper we advocate formal locality analysis on memory references of GPGPU kernels. We investigate the locality of reference at different cache levels in the memory hierarchy. At the L1 cache level, we look into the locality behavior at the warp-, the thread block- and the streaming multiprocessor-level. Using matrix multiplication as a case study, we show that our locality analysis accurately captures some interesting and counter-intuitive behavior of the memory accesses. We believe that such analysis will provide very useful insights in understanding the memory accessing behavior and optimizing the memory hierarchy in GPU architectures.
Ohio Hopewell Depictions of Composite Creatures: Part II–Archaeological Context and a Journey to an Afterlife

Archaeological contextual analyses of four artifacts that depicted composite creatures and that were recovered from the Turner earthwork in southwestern Ohio are integrated here with a biological identification of the creatures' component animals and a survey of historic Woodland–Plains Indian knowledge about their roles in Woodland–Plains life (previously reported in this journal). Together, the three studies reveal that the creatures were likely employed in a ritual drama concerned with the welfare of recently deceased persons on their journey to an afterlife through underwater–underground realm(s), where they encountered the creatures. The location of the journey to an afterlife through Below realm(s) differs from that of nearly all historic Woodland–Plains Indians, who knew the journey to take place on the earth-disk or to occur by ascension. Implications of the ritual drama at Turner for some recent interpretive trends in Woodland archaeology are explored, including an overemphasis on “world renewal”...
Scalable, fault-tolerant management in a service oriented architecture

The service-oriented architecture has come a long way in solving the problem of reusability of existing software resources. Grid applications today are composed of a large number of loosely coupled services. While this has opened up new avenues for building large, complex applications, it has made the management of the application components a non-trivial task. Management is further complicated when services exist on different platforms, are written in different languages, present in varying administrative domains restricted by firewalls and are susceptible to failure. This paper investigates problems that emerge when there is a need to uniformly manage a set of distributed services. We present a scalable, fault-tolerant management framework. Our empirical evaluation shows that the architecture adds an acceptable number of additional resources making the approach feasible.
An NCME Instructional Module on: Setting Passing Scores

This module describes standard setting for achievement measures used i n education, licensure, and certification. On completing the module, readers will be able to: describe what standard setting is, why it is necessary, what some of the purposes of standard setting are, and what professional guidelines apply to the design and conduct of a standard-setting procedure; differentiate among different models of standard setting; calculate a cutting score using various methods; identify appropriate sources of validity evidence and threats to the validity of a standard-setting procedure; and list some elements to be considered when evaluating the success of a standard-setting procedure. A self-test and annotated bibliography are provided at the end of the module. Teaching aids to accompany the module are available through NCME.
Relative Opsonic and Protective Activities of Antibodies against K1, O and Lipid A Antigens of Escherichia Coli

AbstractThe K1 Escherichia coli capsular antigen has been implicated as a virulence factor because of the frequency of isolation of K1 containing strains from certain invasive human infections. In the study of the interaction between K1 strains, normal human polymorphonuclear cells (PMNs) and fresh human serum, we have found varying susceptibility to phagocytosis and killing; thus, the in vitro opsonophagocytic and in vivo protective role of K1, somatic O and core glycolipid antibodies remain unclear. We have therefore examined strains of E. coli with defined susceptibility to phagocytosis by normal PMNs and sera and compared the effect of K1, somatic O and lipid A antibodies in opsonophagocytic tests and mouse protection experiments. K1 E. coli strains demonstrating relative resistance to phagocytosis and killing were effectively opsonized only with specific K1 capsular antisera. Similarly, K1 capsular antisera, but not anti-O or lipid A antisera, also provided protection in mice challenged with a LD100 ...
Validation of a General Fatigue Life Prediction Methodology for Sn–Ag–Cu Lead-Free Solder Alloy Interconnects

A general fatigue life prediction methodology, based on a unified creep plasticity damage (UCPD) model, was developed for predicting fatigue cracks in 95.5Sn-3.9Ag-0.6Cu (wt %) solder interconnects. The methodology was developed from isothermal fatigue tests using a double-lap-shear specimen. Finite element analysis model geometries, mesh densities, and assumptions were detailed for both a full model (an octant-symmetry slice of the entire ball grid array (BGA) assembly) and a submodel (the solder joint deemed most likely to fail and the surrounding package layers) to facilitate fatigue prediction. Model validation was based on the thermal mechanical fatigue of plastic BGA solder joints (250-4000 thermal cycles, -55°C to 125°C, and 10°C/min). Metallographic cross sections were used to quantitatively measure crack development. The methodology generally underpredicted the crack lengths but, nonetheless, captured the measured crack lengths within a ±2X error band. Possible shortcomings in the methodology, including inaccurate materials properties and part geometries, as well as computational techniques, are discussed in terms of improving both the UCPD constitutive model and the fatigue life prediction methodology fidelity and decreasing the solution time.
Effect of an Inert Gas on Heat and Mass Transfer in a Vertical Channel With Falling Films

The effect of inert (noncondensable) gases on the heat and mass transfer (absorption) for channel flow of water vapor in conjunction with falling aqueous LiBr films is investigated. The hydrodynamic flow of the gas in the channel is approximated as fully developed. This is a fair assumption because of the low Reynolds numbers resulting from the low prevailing absorber pressures. The film flow is also assumed to be hydrodynamically developed. This greatly simplifies the problem, as the momentum equation need not be considered. Otherwise the continuity, species, and thermal energy equations govern the problem. Numerical results for a nominal case are presented for the velocity, temperature, and species distributions in the gas and liquid phase regions, and for the interface absorption rate. The effects of varying several parameters (including inerts concentration) on the above variables are also presented. Comparisons are also made with limited data in the literature.
Optical Mellin transforms using computer generated holograms

Abstract The scale invariant correlation possible with Mellin transforms has made this operation extremely important in pattern recognition for image and signal processing. This operation is realized by a geometrical transformation ƒ(x, y) → ƒ( exp ξ, exp η) followed by an optical Fourier transform. The use of computer generated hologram masks to effect the ξ = ln x , η = ln y transformation are discussed.
The voltage and current transfer ratios of RLC operator networks

Abstract The subject of this work is the voltage and current transfer ratios of three-terminal networks having no mutual coupling and whose impedances are analytic functions taking their values in an abelian self-adjoint algebra of bounded linear operators on a Hilbert space. Each such value is also assumed to be invertible. It is shown that these ratios have the form [I + A(ζ)]−1, where, for each ζ in a sufficiently small open cone in the right-half complex plane with apex at the origin and the real axis as its bisector, the numerical range of A(ζ) is contained in a compact subset of the open right-half plane. This implies that the ratios are strictly contractive for each ζ in the cone. The angle of the cone is π (2k + 2) , where k is the number of internal nodes of a certain “surrogate” network; this result is best possible. For two-terminal-pair networks the ratios are shown to be strictly contractive for each ζ in a similar cone with angle π (2k + 4) .
Joint impairment and hand function in the elderly.

Objective To test the contribution of joint impairment to observed hand function (grip strength and Williams Test) in the elderly, using a multivariate model. Design Cross-sectional observational data (baseline data from an ongoing longitudinal study). Subjects Five hundred forty-one persons over age 60, including continuing care retirement community (n = 222), homebound (n = 72), and ambulatory (n = 247) respondents. Mean age at assessment 76.7, (SD = 9.0). Measurement Independent variables included sociodemographics, physician measures of upper joint impairment, an index of comorbidities derived from physical examination or chart abstract, self-assessed arthritis pain, depression, and anxiety. The dependent variables included grip strength and a modified Williams Test [Williams Test (M)]. Main Results The multiple regression explained 59% (Adjusted R2 = .59) of the variance in grip strength, with joint impairment accounting for a change in R2 of .07. Upper joint impairment and grip strength accounted for 3% and 5%, respectively, of the variance in the Williams Test (M) (total amount of explained variance = 45%). Conclusions Demographics explain most of the variance in grip strength and performance on the Williams Test (M). Controlling for demographics, musculoskeletal disease represented by joint impairment is associated with diminished grip strength. Reduced grip strength is associated with poorer performance on the Williams Test (M).
The problem of sequence determination in transfer RNA.

Abstract The nucleotide sequences in certain hectonucleotides can be deduced if, following cleavage with four monobase-specific enzymes, the larger fragments can be separated and their internal sequences determined. Unique sequence determinations do not appear possible if only three monobase specific enzymes or only less specific enzymes are available, but certain combinations of three nucleases are nearly adequate. Adequate experimental procedures now appear to have been developed. The principal obstacle to determining sequences in transfer RNA is that the set of four monobase specific nucleases is not yet complete. The determination of sequence in transfer RNA may in practice be less demanding than the theory here implies. If there are on the average five unusual bases per molecule (Cantoni et al. , 1962) and if the position of these bases is specific,' this will aid sequence determination. If, as recent studies imply (Spencer et al. , 1962), most of the transfer RNA nucleotides occur in Watson-Crick base pairs, then the determination of part of the sequence will aid in choosing appropriate order for the rest of the sequence.
Base adduct interactions with nickel(II) and copper(II) β-ketoenolates

Abstract The interactions of organic bases with several nickel(II) and copper(II) β-ketoenolates are described. The dipivaloylmethane complexes of copper(II) with bases are mono adducts, presumably five coordinate, while the adducts with nickel(II) dipivaloylmethane are psuedo-octahedral bis adducts. The nucleophilicity of the organic base toward the copper(II) atoms is shown to be influenced by steric as well as electronic considerations.
Positive Organizational Change

For 50 years, JABS has played a significant role in making available new knowledge about organizational change. In the last decade, JABS has once again been at the forefront of introducing a new ap...
Stochastic Stability of Coupled Oscillators With One Asymptotically Stable and One Critical Mode

An analytic explanation is given for the experimental results reported by Popp and Romberg (2001, "Influence of Stochastic Effects on Flow Induced Vibrations in Tube Bundles, " IUTAM Symposium on Nonlinearity and Stochastic Structural Dynamics (Solid Mechanics and Its Applications), S. Narayanan and R. N. Iyengar, eds., Kluwer Academic, Dordrecht, Vol. 85, pp. 197-208) on fluid flow over tube bundles by using the concept of the maximal Lyapunov exponent. The motion of one tube in the bundle is modeled as a two-degree-of-freedom (four dimensional) system with one critical mode and one asymptotically stable mode driven by a small intensity stochastic process. We obtain a general asymptotic approximation for the maximal Lyapunov exponent for this four dimensional system and explain how the stochastic components that couple the critical and stable modes play an important role in determining whether a noisy excitation can stabilize or destabilize the oscillatory critical mode.
Multicellular Regulation of Tensional Homeostasis

Vascular endothelial cells are exposed to routine and directed mechanical forces due to the pulsatile nature of blood flow. As a result, these cells undergo cytoskeletal remodeling and elicit adaptive changes in cell signaling that protect them against atherosclerosis. A main purpose of this remodeling is to minimize alterations in intracellular mechanical tension caused by external forces and to maintain it at a preferred (homeostatic) level. It has been purported that normal physiological functions of the endothelium requires tensional homeostasis across a broad range of length scales, from the subcellular level to the tissue level. Our recent study challenged this view, however. We measured reorientation of cellular traction forces in isolated endothelial cells in response to periodic uniaxial stretch. We found that within ∼40-50 min from the onset of stretch the traction field reorients in the direction perpendicular to the stretch axis, but exhibits a highly dynamic and erratic behavior long after reorientation is completed. Moreover, even in the absence of external stretch the traction field remains dynamic and erratic while the cell spreading area changes very little and cells do not migrate. Here, we hypothesized that tensional homeostasis of the endothelium requires intercellular cooperation. We measured cellular traction forces in two-dimensional endothelial cell clusters of different sizes and at different length scales over an extended time period and analyzed traction dynamics. Our analysis revealed that dynamic fluctuation of traction forces diminished with increasing cluster size and with increasing strength of the traction field, suggesting that cell-cell cooperation might promote tensional homeostasis in the endothelium. Using a mathematical model, we showed that the cell clusters might regulate the homeostatic state of stress through mechanical interdependence between adjacent cells.
Direct simulation Monte Carlo-based expressions for the gas mass flow rate and pressure profile in a microscale tube

The direct simulation Monte Carlo (DSMC) method of Bird is used to develop simple closed-form expressions for the mass flow rate and the pressure profile for the steady isothermal flow of an ideal gas through a microscale tube connecting two infinite reservoirs at different pressures but at the temperature of the tube wall. Gas molecules reflect from the tube wall according to the Maxwell model (a linear combination of specular and diffuse reflections at the wall temperature) with a unity or sub-unity value of the accommodation coefficient (the probability that molecules reflect diffusely from the wall). The DSMC-based expressions have four parameters. Two parameters are specified so that the mass flow rate reduces to the known expression in the free-molecular regime. One parameter was previously determined by comparison to DSMC simulations in the slip regime. The remaining parameter is determined by comparison to DSMC simulations for pressures spanning the transition regime with several values of the accommodation coefficient. The expressions for the mass flow rate and the pressure profile agree well with the DSMC simulations (rms and maximum differences of 2% and 5% for all cases examined), with other more complicated expressions and with recent experiments involving microscale tubes and channels for all flow regimes.
Lubricant behavior in high vacuum.

High vacuum effects on dry friction coefficient, lubricated friction coefficient and load carrying capacity of lubricants
Failure mechanisms in silicon transistors deduced from step stress tests

Abstract Step stress testing is presented as a useful tool for determining potential failure mechanisms in silicon transistors, but it has serious limitations when attempting to predict reliability. The mechanisms of mechanical failure have been studied intensively and many examples from pmp and npn designs are presented and analysed.
Specific chromosome anomalies and predisposition to human breast, renal cell, and colorectal carcinoma

Specific chromosome abnormalities in three human solid tumors of adulthood--renal cell carcinoma, breast tumor, and colon carcinoma--are described. Two of the neoplasms are associated with a reciprocal translocation involving chromosome #3 (breakpoint at band p13-14 with 6, 8, 11, and 16) in renal cell carcinomas and chromosome #1 (breakpoint at band q21 with chromosomes #3, #5, #10, #11, and #12) in breast carcinomas. Most of these chromosomal rearrangements have been seen as tumor-specific acquired changes in tumor cells, as well as some constitutionally present in normal tissues of patients. In a limited number of colorectal carcinoma samples a deletion in the short arm of a chromosome #12 is implicated as a specific abnormality. The expression of fragile sites in these specific chromosomal regions in the normal peripheral blood cultures might identify an individual predisposed to develop a particular type of neoplasm.
A fluidic microenergy generator enabled by hybrid nanomaterial nanofluids

Nanofluid, a type of fluid with dispersed nanoparticles, has been studied and used as a direct absorber of solar or thermal energy for the past years. Herein, a fluidic energy generator enabled by a new type of nanofluid is developed, which has also been used to power a thermistor successfully. This type of nanofluid contains single-walled carbon nanotube-CuS nanoparticles (SWNT-CuS NPs) hybrid nanomaterial. Experiments found it has a significantly enhanced capability for the absorption and storage of the solar thermal energy compared to water. The fluidic energy generator enabled by 50 μL nanofluid can generate output voltage up to 100 μV, and thus can operate small electronic devices or sensors by directly converting the solar thermal energy into electricity.
THE RELATIONSHIP OF PRIOR TRAINING AND PREVIOUS TEACHING EXPERIENCE TO SELF-EFFICACY AMONG GRADUATE TEACHING ASSISTANTS

This study, based on the theoretical model of Teacher Self-Efficacy proposed by Denham and Michael (1981), explored the effects of prior training, previous teaching experience, and certain demographic variables on the teaching self-efficacy of graduate teaching assistants. An adapted version of the Self-Efficacy Toward Teaching Inventory (Tollerud, 1990) was administered to a sample of graduate teaching assistants. Graduate teaching assistants with prior training endorsed a significantly higher level of self-efficacy than those with no training. Correlational analyses demonstrated significant positive relationships between prior training and previous teaching experience with level of self-efficacy. Multiple regression analysis indicated that previous teaching experience explained a significant amount of variance in self-efficacy. Results are discussed in light of the current training and utilization of graduate teaching assistants, and suggestions for future research are offered.
Development of a novel bioassay system to assess the effectiveness of entomopathogenic fungi against imported fire ants

Abstract A novel spray tower was developed for bioassay of biopesticide formulations. The virulence of Metarhizium brunneum and Metarhizium anisopliae ATCC 62176 was evaluated against imported fire ants. Both isolates were virulent but M. brunneum was more effective against imported fire ants. Results proved this apparatus was reliable, sensitive and accurate.
Global optimization of structural systems using two new methods

Two new methods for finding global minimum points are applied to several truss and frame structural design problems. Basic ideas and procedures of the methods are explained. One of the methods finds many local minimum solutions while the second method is concerned mainly with finding only the global solution (however, it may find other local minima as well). A set of twenty-eight structural design test problems is devised by using two materials (steel and aluminium) and three cross-sectional shapes. The problems are solved with the two methods, and the results are analysed. Comparisons are made for the results with the truss and frame model for the same structure, use of steel or aluminium as the construction material, and use of different cross-sectional shapes. It is shown that many structural optimization problems possess several local minima, and so the global optimization methods can be useful for their solution. However, the computational effort to find a global solution can be substantial because many local minimizations must be performed. It is concluded that both the methods are useful for finding global minimum solutions for structural optimization problems.
Dynamics of scroll rings in a parameter gradient

Experimental observations of scroll rings in excitable media have shown that an externally applied parameter gradient can significantly alter the dynamics of the ring, leading to rotation of the plane of the ring, variations in its rate of collapse, and distortions in its shape. Here we propose a theory to account for these effects by extending the theory of local filament dynamics to include the influence of the parameter gradient. Numerical simulations using the FitzHugh-Nagumo equations show that the proposed theory works well when the differences in rotation periods at different parts of the filament are sufficiently small. When this condition does not hold, the theory must be modified to take into account nonlocal interactions.
Oxidation As A Major Cause Of Defects In Electron-Beam And Optical Resists

In response to a study conducted at Perkin-Elmer ALO, which showed that surface anomalies present on PBS-coated masks prior to exposure were responsible for more than 50 percent of the chrome spot defects observed on the finished masks, Perkin-Elmer EBT initiated a study focusing on the causes of the defects found in the original materials. This study found that chemical oxidation, not foreign particulate contamination, was the major cause of the discrete defects found on PBS films. Elemental analysis of the small defects on fresh PBS-coated quartz masks with a scanning electron microscope, energy-dispersive x-ray analysis, and Auger spectroscopy showed that 66 percent of the defects contained little or no elemental contamination other than excess oxygen. X-ray photoelectron spectroscopy and small-spot refective infrared analysis of larger oxidized defects on older plates and of defects induced by known initiators of oxidation in polymers yielded information on chemical functional groups in the defects. This information confirmed the finding that oxidation was responsible for the changes observed in discrete areas. Oxidation changes the physical and chemical properties of the reacting area and produces an embedded particle or pinhole that causes a chrome spot or pinhole defect in the finished mask. Perkin-Elmer EBT has matched chrome spot defects that are images of known oxidized areas on PBS films with chrome spot defects detected by a KLA on finished production masks at Perkin-Elmer ALO. That similar defects have been observed on PMMA, EBR-9, and several kinds of AZ optical resists allows us to predict that oxidation of resists increases defect densities in all types of microlithography. The mechanisms of oxidation that result in discrete defects are described, and ways of reducing or eliminating such defects are discussed.© (1987) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Deep mRNA Sequencing of the Tritonia diomedea Brain Transcriptome Provides Access to Gene Homologues for Neuronal Excitability, Synaptic Transmission and Peptidergic Signalling

Background The sea slug Tritonia diomedea (Mollusca, Gastropoda, Nudibranchia), has a simple and highly accessible nervous system, making it useful for studying neuronal and synaptic mechanisms underlying behavior. Although many important contributions have been made using Tritonia, until now, a lack of genetic information has impeded exploration at the molecular level.
Administration of GM1 ganglioside eliminates neuroleptic-induced sensorimotor deficits in MPTP-treated mice

Injection of a low dose of haloperidol, that has no obvious behavioral effects in normal mice, produces akinesia, catalepsy, and sensory neglect in MPTP-treated mice. GM1 ganglioside treatment eliminates all of these behavioral impairments and also partially restores striatal dopamine content. These observations suggest that the MPTP-treated mouse may be a valuable model for studying mechanisms underlying parkinsonism and that administration of GM1 ganglioside may be an effective therapy.
DEVELOPING A DEFENSIVE PRODUCT MANAGEMENT PHILOSOPHY FOR THIRD WORLD MARKETS

The article suggests that product management techniques commonly employed for markets in developed countries are inappropriate for markets in less‐developed countries (LDCs). To market successfully in LDCs, a firm must re‐examine both its product offerings and its product management philosophy.
The 1.3 A crystal structure of a biotin-binding pseudoknot and the basis for RNA molecular recognition.

A pseudoknot-containing aptamer isolated from a pool of random sequence molecules has been shown previously to represent an optimal RNA solution to the problem of binding biotin. The affinity of this RNA molecule is nonetheless orders of magnitude weaker than that of its highly evolved protein analogs, avidin and streptavidin. To understand the structural basis for biotin binding and to compare directly strategies for ligand recognition available to proteins and RNA molecules, we have determined the 1.3 A crystal structure of the aptamer complexed with its ligand. Biotin is bound at the interface between the pseudoknot's stacked helices in a pocket defined almost entirely by base-paired nucleotides. In comparison to the protein avidin, the aptamer packs more tightly around the biotin headgroup and makes fewer contacts with its fatty acid tail. Whereas biotin is deeply buried within the hydrophobic core in the avidin complex, the aptamer relies on a combination of hydrated magnesium ions and immobilized water molecules to surround its ligand. In addition to demonstrating fundamentally different approaches to molecular recognition by proteins and RNA, the structure provides general insight into the mechanisms by which RNA function is mediated by divalent metals.
Plasma Skimming in Vascular Trees: Numerical Estimates of Symmetry Recovery Lengths

A new model of plasma skimming in vascular trees that includes the history of disturbances at previous bifurcations is developed. The model calculates the shift in the red blood cell concentration profile by mapping streamlines through the junction; it then computes the dissipation of that disturbance through random collisions among the cells. A numerical solution of this model is compared to experimental data on plasma skimming in serial bifurcations. Numerical values of symmetry recovery lengths downstream of the bifurcation are calculated using the model. Comparison of the computed symmetry recovery lengths with anatomical measurements in hamster cremaster muscle indicate that asymmetries in red blood cell concentration profiles are important in vessels with diameters below 55 μm.