cssi/SciSciGPT-SciSciNet huggingface dataset:
Design of analogues of parathyroid hormone: A conformational approach

An approach to the design of peptide-hormone analogues in which amino acid substitutions are based on predicted effects on secondary structure was investigated. The structural requirements for parathyroid-hormone (PTH) action are distinct from the determinants necessary for receptor binding alone without subsequent activation of adenylate cyclase. Two analogues of PTH containing substitutions in the principal binding domain of PTH, the region 25–34, were synthesized by the solid-phase method and evaluated for bioactivity. The sequence 25–34 was predicted to have nearly equal conformational potential for both α-helix and β-sheet using Chou and Fasman parameters. A previously studied analogue, [Tyr34]bPTH(1–34) amide, containing substitutions in this region, was more active than was bPTH-(1–34). The substitution of tyrosine for phenylalanine at position 34 in this analogue is predicted to promote β-sheet conformation. The analogues [Ile28, Tyr30, Tyr34]bPTH-(1–34) amide and [Arg32, Tyr34]bPTH-(1–34) amide each contain substitutions predicted to further enhance or stabilize β-sheet formation. The solution conformation of these analogues, determined by circular dichroism studies in an aqueous buffer and an organic solvent, indicated promotion of β-sheet secondary structural content in both analogues in a hydrophobic environment chosen to simulate that of the interaction of the peptide and the membrane receptor. In contrast, the native sequence lacks β-structure. Biological activity of these analogues in the rat renal adenylate cyclase assay in vitro and binding affinity in a radioreceptor assay were threefold those of unsubstituted PTH-(1–34). Peptide analogue design based on conformational prediction, rather than substitution of primary structure alone, offers an attractive alternative approach to the development of hormone analogues and antagonists.
Theoretical development of nursing interventions for sudden cardiac arrest survivors using social cognitive theory

This article discusses the theoretical development of a nursing intervention program to enhance recovery over the first year following sudden cardiac arrest. Concepts from social cognitive theory and domains of concern following sudden cardiac arrest underpin a tailored and standardized nursing intervention. The nursing intervention program is designed for delivery by means of telephone and through the mail. Testing of the nursing intervention program is underway using a clinical trial design.
Simulated annealing for the design of structures with time-varying constraints

The optimal design of structural systems with conventional members or systems with conventional as well as passive or active members is presented. The optimal sizes of the conventional members of structural systems are obtained for dynamic loads. A modified simulated annealing algorithm is presented which is used to solve the optimization problem with dynamic constraints. The present algorithm differs from existing simulated annealing algorithms in two respects; first, an automatic reduction of the search range is performed, and second, a sensitivity analysis of the design variables is utilized. The present method converges to the minimum in less iterations when compared to existing simulated annealing algorithms. The algorithm is advantageous over classical methods for optimization of structural systems with constraints arising from dynamic loads. For certain initial values of the design variables, classical optimization methods either fail to converge or produce designs which are local minima; the present algorithm seems to be successful in yielding the global minimum design.
Nuclear energy: Frontiers

Fission power could fulfil our needs without generating any greenhouse gases, but we will need to find novel ways to use it that will reduce its risks
Effect of constitutive behavior on scratch visibility resistance of polymers—A finite element method parametric study

Three-dimensional finite element method (FEM) parametric study was performed by simulating linearly progressive load scratch process on a polymer substrate with a spherical-tip indenter, following the established ASTM D7027-05 and ISO 19252:08 testing protocol. The scratch depth and shoulder height of the groove formed during scratch, which has been shown to be directly related to the scratch visibility resistance of polymers, is simulated by varying a set of material constitutive parameters, namely, yield stress, strain softening slope, strain hardening slope, strain at stress recovery, and strain before hardening. The simulation results indicate that yield stress and strain at stress recovery are two most important parameters that affect scratch depth and shoulder height, thus scratch visibility resistance, of a polymer. Implication of the present findings for designing scratch resistant polymers is discussed.
Targeted searches for gravitational waves from radio pulsars

An overview of the searches for gravitational waves from radio pulsars with LIGO and GEO is given. We give a brief description of the algorithm used in these targeted searches and provide end-to-end validation of the technique through hardware injections. We report on some aspects of the recent S3/S4 LIGO and GEO search for signals from several pulsars. The gaussianity of narrow frequency bands of S3/S4 LIGO data, where pulsar signals are expected, is assessed with Kolmogorov-Smirnov tests. Preliminary results from the S3 run with a network of four detectors are given for pulsar J1939+2134.
When Bad Departments Happen to Good People

This case study examines the lives of some very different educational leadership professors with a common problem: They are miserable in their work. But how could this be? They have secure jobs at a great university, considerable autonomy in their work schedules, an opportunity to study a subject they love, and a chance to work with great students. What is the problem? The problem is that they now find themselves among the ranks of the damned in the Leadership Department From Hell, or at least their local chapter of this ever-growing franchise. This hypothetical case study presents several archetypal characters known to inhabit the most troubled leadership departments in order to examine what can go wrong in a leadership department. This study also presents guiding discussion questions to explore what might be done to make it better—for everyone.
A gas convection model of heat transfer in large particle fluidized beds

A steady gas convection model of heat transfer to a horizontal cylinder immersed in a large particle gas fluidized bed has been developed. The model is based upon the hypothesis that the large particles will be isothermal and includes the effect of radiation as well as interstitial turbulence. Results of calculations based on the model, for a two-dimensional bubbling bed, indicate that a single bubble, having a diameter equal to the cylinder diameter, has a relatively small influence on the total heat transfer.
Aging behavior of PVA hydrogels for soft tissue applications after in vitro swelling using osmotic pressure solutions.

Abstract The osmotic pressure of the medium used for in vitro swelling evaluation has been shown to have a significant effect on the swelling behavior of a material. In this study, the effect of osmotic pressure during swelling on poly(vinyl alcohol) hydrogel material properties was evaluated in vitro . Osmotic pressure solutions are necessary in order to mimic the swelling pressure observed in vivo for soft tissues present in load-bearing joints. Hydrogels were characterized after swelling by mechanical testing, X-ray diffraction and optical microscopy in the hydrated state. Results indicated that hydrogel mechanical properties remained tailorable with respect to initial processing parameters; however, significant aging occurred in osmotic solution. This was observed when evaluating the mechanical properties of the hydrogels, which, before swelling, ranged from 0.04 to 0.78 MPa but, after swelling in vitro using osmotic pressure solution, ranged from 0.32 to 0.93 MPa. Significant aging was also noted when evaluating crystallinity, with the relative crystallinity ranging between 0.4 and 5.0% before swelling and between 6.5 nd 8.0% after swelling. When compared to swelling in a non-osmotic pressure solution or in phosphate-buffered saline solution, the mechanical properties were more dependent upon the final swelling content. Furthermore, increases in crystallinity were not as significant after swelling. These results highlight the importance of choosing the appropriate swelling medium for in vitro characterization based on the desired application.
Gait alterations in dogs after transection of the anterior cruciate ligament

We calculated mean peak vertical forces (MFz) of each limb of 9 adult mongrel dogs before and 2 weeks, 6 weeks, and 12 weeks after left anterior cruciate ligament transection (ACLT). Five additional dogs were studied before and 2 weeks and 6 weeks after sham ACLT. The gaits of 3 dogs that had undergone ACLT 2.5 years previously were also analyzed. Preoperatively, there were no differences in the MFz of the right and left hind limbs of the 9 dogs; we found that each limb exerted approximately 70% of the dog's static body weight on the force plate. Two weeks following ACLT, the MFz of the operated limbs decreased to 25% of the static body weight, while at 6 weeks and 12 weeks after surgery, the MFz generated by the operated limbs rose to about 32% and 37% of static body weight, respectively. No change was noted in the MFz of the contralateral hind limbs. In the 3 dogs that had undergone ACLT 2.5 years earlier, the MFz in the unstable stifle joint was 50% of static body weight. At both 2 weeks and 6 weeks after surgery, the MFz values for all 4 limbs of the animals subjected to sham ACLT were comparable with baseline values. These observations indicate that the osteoarthritic changes seen in the unstable limb are associated with decreased loading of that limb, without increased (compensatory) loading of the contralateral hind limb.
Inactivation of wild-type and rad mutant Caenorhabditis elegans by 8-methoxypsoralen and near ultraviolet radiation.

— Survival of wild-type and four radiation-sensitive (rad) mutants of the nematode Caenorhubditis eleguns was determined after near-UV irradiation in the presence of 8-methoxypsoralen (8-MOP). Three sets of inactivation profiles were generated for each strain by irradiating synchronous populations of either early embryos, late embryos or first-stage larvae (L1s). Late embryos were consistently the most sensitive. Curiously, none of the four rad mutants were even moderately hypersensitive. Split-dose experiments indicated that DNA-DNA crosslinks were primarily responsible for lethality. Crosslink induction and repair were determined using two different assays. In both cases, little if any repair was observed in wild-type. This lack of repair thus explains why the rad mutants were not hypersensitive to 8-MOP photoinactivation. Since early embryos undergo extensive cell cycling, their resistance to 8-MOP photoinactivation suggests that replication is highly refractory to both monoadducts and crosslinks, as has been demonstrated previously for UV radiation-induced photoproducts (Hartman et al., 1991, Mutat. Rex, 255, pp. 163–173).
Conversion of p,p-DDT to p,p-DDD by Intestinal Flora of the Rat

p,p-DDD [1,1-dichloro- 2,2-bis(p-chlorophenyl)-ethane] occurs in the feces and livers of rats, that are given p, p-DDT [1,1,1-trichloro-2,2-bis-(p-chlorophenyl)-ethane] by stomach tube, but not of rats injected intraperitoneally with p,p-DDT. Coliform bacteria, isolated from feces of control animals, can effect reductive dechlorination of p,p-DDT to p,p-DDD. These findings indicate that the normal flora of the gastrointestinal tract, rather than the liver, as others have suggested, is the major source of the p,p-DDD that is found in animals fed p,p-DDT.
Assessing the relative accuracies of two screening tests in the presence of verification bias.

Epidemiological studies of dementia often use two-stage designs because of the relatively low prevalence of the disease and the high cost of ascertaining a diagnosis. The first stage of a two-stage design assesses a large sample with a screening instrument. Then, the subjects are grouped according to their performance on the screening instrument, such as poor, intermediate and good performers. The second stage involves a more extensive diagnostic procedure, such as a clinical assessment, for a particular subset of the study sample selected from each of these groups. However, not all selected subjects have the clinical diagnosis because some subjects may refuse and others are unable to be clinically assessed. Thus, some subjects screened do not have a clinical diagnosis. Furthermore, whether a subject has a clinical diagnosis depends not only on the screening test result but also on other factors, and the sampling fractions for the diagnosis are unknown and have to be estimated. One of the goals in these studies is to assess the relative accuracies of two screening tests. Any analysis using only verified cases may result in verification bias. In this paper, we propose the use of two bootstrap methods to construct confidence intervals for the difference in the accuracies of two screening tests in the presence of verification bias. We illustrate the application of the proposed methods to a simulated data set from a real two-stage study of dementia that has motivated this research.
Blocking in two-level non-regular fractional factorial designs

In this paper we consider screening experiments where a two-level fractional factorial design is to be used to identify significant factors in an experimental process and where the runs in the experiment are to occur in blocks of equal size. A simple method based on the foldover technique is given for constructing resolution IV orthogonal and non-orthogonal blocked designs and examples are given to illustrate the process.
MOLECULAR DYNAMICS SIMULATIONS OF LIQUID CRYSTAL ANCHORING AT AN AMORPHOUS POLYMER SURFACE

Atomistic molecular dynamics simulations have been used, apparently for the first time, to investigate the anchoring behavior of a liquid crystal at the interface with an amorphous polymer. The simulations studied a system consisting of the nematogen 5CB at the surface of amorphous polyethylene, and used the simple Dreiding II force field. The simulations indicate a preference for nonplanar anchoring. Two distinct microscopic paths have been identified by which the liquid crystal changes orientation at the surface. In one case, only one or a few of the 5CB molecules are rotating at any particular time. In the other case, a substantial fraction of the molecules rotate simultaneously.
Existence in the large of periodic solutions of hyperbolic partial differential equations

where u = (u 1 . . . . , u.), and f = (fl . . . . . f . ) is periodic in x and y of period T, presents a number of difficulties when no damping of any sort is assumed. In this paper we analyze this difficult problem in the line of our previous work on ordinary and partial differential equations. We conclude with criteria of existence for solutions to the problem above. These criteria can then be used for the analogous problem for the equation uxx-u,y=g(x, y, u, ux, u~,). (2)
Identifying Motifs for Phosphatidylcholine Activation of Bacterial Phosphatidylinositol-Specific Phospholipase C Enzymes

Phosphatidylinositol-specific phospholipase Cs (PI-PLCs) secreted by pathogenic bacteria are often virulence factors. For one well-studied example, Bacillus thuringiensis PI-PLC (BtPI-PLC), the presence of the non-substrate lipid phosphatidylcholine (PC) in membranes enhances both membrane binding and enzymatic activity towards phosphatidylinositol (PI). A strip of four surface-exposed Tyr residues near the rim of the α/β-barrel are involved in this enhancement, and it has been proposed that this strip contributes to a specific PC binding site. The related PI-PLC from Staphylococcus aureus (SaPI-PLC), has similar kinetic characteristics to BtPI-PLC, but has only two Tyr residues in the same region. While SaPI-PLC can also be specifically activated towards PI cleavage by incorporation of PC into assay systems, SaPI-PLC membrane binding as a function of PC content is considerably weaker than that of BtPI-PLC. Mutagenesis of the two SaPI-PLC Tyr residues (Y253S/Y255S) reduces interfacial activity of SaPI-PLC. Adding the two ‘missing’ Tyr residues (N254Y/H258Y) did not further enhance SaPI-PLC specific activity but it dramatically enhanced binding of the protein to PC-rich vesicles. This suggests that PC activation is more complicated than simply binding the protein to membranes. Comparing enzyme kinetics and the effects of mutations on BtPI-PLC, SaPI-PLC and the PI-PLC from an intracellular pathogen (Listeria monocytogenes) suggests a rationale for the acquisition of a discrete PC binding site in some, but not all, PI-PLC enzymes.
Allosteric Transitions of Supramolecular Systems Explored by Network Models: Application to Chaperonin GroEL

Identification of pathways involved in the structural transitions of biomolecular systems is often complicated by the transient nature of the conformations visited across energy barriers and the multiplicity of paths accessible in the multidimensional energy landscape. This task becomes even more challenging in exploring molecular systems on the order of megadaltons. Coarse-grained models that lend themselves to analytical solutions appear to be the only possible means of approaching such cases. Motivated by the utility of elastic network models for describing the collective dynamics of biomolecular systems and by the growing theoretical and experimental evidence in support of the intrinsic accessibility of functional substates, we introduce a new method, adaptive anisotropic network model (aANM), for exploring functional transitions. Application to bacterial chaperonin GroEL and comparisons with experimental data, results from action minimization algorithm, and previous simulations support the utility of aANM as a computationally efficient, yet physically plausible, tool for unraveling potential transition pathways sampled by large complexes/assemblies. An important outcome is the assessment of the critical inter-residue interactions formed/broken near the transition state(s), most of which involve conserved residues.
Leak Detection—Transient Flow Simulation Approaches

The basis for and field trials of two leak detection algorithms by transient flow simulations are presented. Data noise in pressure and flow measurements are considered. Noise is found to limit leak detectability. The ability of the two algorithms to reliably detect small to moderate size leaks under steady and transient flow conditions is demonstrated.
An improved temperature-jump apparatus

Abstract A temperature-jump device of the type devised by M. Eigen (1954, Discuss, Faraday Soc.17, 194–210) was built using an 8000- to 40,000-V capacitor discharge to raise the temperature of a conductive sample as much as 25°C within 5 μs. The temperature-jump cell design, which differs from that of previously built cells, consists of cylindrical electrodes fitted into a quartz cylindrical observation cell. This allowed for variable electrode spacing and eliminated high-voltage arcing as well as the need to degas samples to prevent solution cavitation. The temperature of a 0.3- to 3.0-ml sample volume could be adjusted over a −20 to 60°C temperature range by circulating 20% glycerol in water through the hollow, stainless-steel electrodes. Absorption, fluorescence, and scattering measurements could be made over the wavelength range 220 to 750 nm with signal to noise ratios generally exceeding 1000:1. A battery-driven, high-intensity mercury arc lamp provided stable, ripple-free light. The optical signal was amplified, digitized by a waveform recorder, transferred to a computer, and analyzed numerically to resolve multiple-exponential decay processes. The performance of this apparatus is illustrated by several membrane-substrate interactions.
Intake of a QHCI-sucrose solution by carbohydrate-deprived rats

Carbohydrate-deprived rats were given an ad-lib choice between an aversively masked sucrose solution and water. Without an opportunity to associate the aversive taste with a beneficial post-ingestion effect, peripheral palatability inhibited selection in accordance with need. With this experience, however, aversive taste was bypassed in favor of selection according to dietary need.
SOME EFFECTS OF THE ADMINISTRATION OF THIOURACIL TO MONKEYS1

THE GOITROGENIC effects of thiourea, the sulfonamides and related compounds such as thiouracil have been well known since the reports by the Mackenzies (1941, 1943) and the extensive investigations of Astwood and associates (1943 et seq.). The action of thiouracil in the rat and other lower forms has been discussed by many investigators. The potential therapeutic value of the drug has led to numerous and careful investigations of its action in man (Astwood 1943, 1944 et al.). For further experimental study the adult rhesus monkey (Macaca mulatta) was chosen. Other studies on the effect of hypothyroidism in these animals have been reported from this laboratory (Jailer, Sperry, Engle and Smelser 1944;Engle 1944) and afford several measurements of thyroid function which were useful in this investigation.
Single-element simulations of partial-drainage effects under monotonic and cyclic loading

Abstract Liquefaction-induced seepage and pore-water pressure redistribution can locally change a sands' void ratio, such that in-situ strength and deformation behavior following an earthquake depend on the coupled diffusion process and not only on pre-earthquake soil properties. The effects of partial drainage on the monotonic, cyclic, and post-cyclic behavior of liquefied sand are explored at the element scale in this study, using the constitutive model PM4Sand [1] and the finite-difference code FLAC [2] . The ability of a critical state-based constitutive model to approximate partially drained loading responses is evaluated by comparing single-element simulations to available lab data and trends. The calibrated model is then used to examine the potential effects of partial drainage on the cyclic stress–strain behavior and accumulation of shear strains for dense-of-critical sand. The importance of liquefaction-induced seepage and void redistribution to the in-situ strength and deformation behavior of liquefied sands is discussed in view of the results of these partially drained laboratory element tests and simulations.
A Highly Conserved Residue in the C-Terminal Helix of HIV-1 Matrix is Required for Envelope Incorporation into Virus Particles

The incorporation of viral envelope (Env) glycoproteins into nascent particles is an essential step in the production of infectious human immunodeficiency virus type 1 (HIV-1). This process has been shown to require interactions between Env and the matrix (MA) domain of the Gag polyprotein. Previous studies indicate that several residues in the N-terminal region of MA are required for Env incorporation. However, the precise mechanism by which Env proteins are acquired during virus assembly has yet to be fully defined. Here, we examine whether a highly conserved glutamate at position 99 in the C-terminal helix is required for MA function and HIV-1 replication. We analyze a panel of mutant viruses that contain different amino acid substitutions at this position using viral infectivity studies, virus-cell fusion assays, and immunoblotting. We find that E99V mutant viruses are defective for fusion with cell membranes and thus are noninfectious. We show that E99V mutant particles of HIV-1 strains LAI and NL4.3 lack wild-type levels of Env proteins. We identify a compensatory substitution in MA residue 84 and show that it can reverse the E99V-associated defects. Taken together, these results indicate that the C-terminal hydrophobic pocket of MA, which encompasses both residues 84 and 99, has a previously unsuspected and key role in HIV-1 Env incorporation.
Amplification of Specific Cyclodiene Insecticide Resistance Alleles by the Polymerase Chain Reaction

Abstract Resistance to cyclodiene insecticides in Drosophila is caused by single-base-pair mutations within the same codon of a γ-aminobutyric acid receptor gene Rdl. These changes cause the deletion of a specific restriction endonuclease site whose presence or absence can be detected in genomic DNA amplified by the polymerase chain reaction in a simple resistance-monitoring technique previously described. However, this method is not capable of distinguishing which resistance allele is present and is not applicable to other species or resistance mechanisms where such a restriction enzyme polymorphism may be absent. Here we describe the use of allele-specific oligonucleotides in the polymerase chain reaction to detect different resistance alleles in Drosophila melanogaster (Meigen) and D. simulans. This technique is capable of genotyping individual insects and of identifying specific resistance alleles and is applicable to other resistance mechanisms associated with point mutations. The implications for insecticide resistance monitoring are discussed.
Real‐space analysis of the exchange‐correlation energy

The exchange-correlation energy of a many-electron system may be written as the electrostatic interaction between the electron density at position r and the density of the exchange-correlation hole at position r + u. If we average the hole over the entire system, we find that the energy is uniquely decomposed into contributions from various electronic separations u. We may also decompose the hole into contributions from parallel and antiparallel spins. We give several exact conditions which this system-averaged, spindecomposed exchange-correlation hole satisfies. Local spin density (LSD) and generalized gradient approximations (GGAS), are more appropriate for u 0 than for large u and more trustworthy for antiparallel spins than for parallel spins. We illustrate how good LSD is as u = 0 with explicit examples, but also note that, contrary to expectation, LSD is not exact for u=0, except in certain limiting cases. We show that the dramatic failure of the second-order gradient expansion for large u can be cured by a real-space cutoff procedure which generates a nonempirical GGA, the Pw91 functional. We conclude with some thoughts about the search for greater accuracy in the next 30 years of density functional theory. © 1995 John Wiley & Sons, Inc.
Concentration of Isotopes by Thermal Diffusion: Rate of Approach to Equilibrium

The time-dependent partial differential equation involved in the theory of the operation of a Clusius thermal diffusion column is discussed. Solutions presented give the concentration of a given isotope at any point in the column as a function of time. Some are compared with experimental results of Nier, and good agreement is obtained.
Surface-sensitive characterization of diamond by ionization electron energy loss spectroscopy

Abstract Ionization loss spectroscopy has been performed on diamond deposited by chemical vapor deposition and on graphite by use of conventional Auger equipment (backscattering geometry). The results are compared with reported data on natural diamond and on graphite. Polycrystalline chemical-vapor-deposited diamond exhibits a spectrum similar to that of natural, single-crystal diamond. Reference is also made to ionization loss spectroscopy in the transmission electron microscope and to near-edge, X-ray absorption fine structure measurements. The prominent features of the measured spectra are correlated with π and σ bonding. The applied method is sensitive to π bonding as well as being surface sensitive and, therefore, is particularly suited to check the deviation from perfect diamond bonding at the surface.
Adult Attachment, Perceived Discrimination Based on Sexual Orientation, and Depression in Gay Males: Examining the Mediation and Moderation Effects

This study examined perceived discrimination as both a mediator and moderator between adult attachment (anxiety and avoidance) and levels of depression in a gay male sample. Survey data were collected from 234 self-identified gay males through the Internet and in person through community resources across several states. Results from structural equation modeling analyses indicated that perceived discrimination partially mediated the relationship between attachment anxiety (but not attachment avoidance) and depression. Moderation of attachment (anxiety and avoidance) by perceived discrimination on levels of depression was not supported. Additionally, about 23% of the variance in perceived discrimination was explained by attachment, and 47% of the variance in depression was accounted for by attachment and perceived discrimination. Clinical implications, limitations, and areas for future research are also discussed.
Myocardial Hypertrophy Overrides the Angiogenic Response to Hypoxia

Background: Cyanosis and myocardial hypertrophy frequently occur in combination. Hypoxia or cyanosis can be potent inducers of angiogenesis, regulating the expression of hypoxia-inducible factors (HIF), vascular endothelial growth factors (VEGF), and VEGF receptors (VEGFR-1 and 2); in contrast, pressure overload hypertrophy is often associated with impaired proangiogenic signaling and decreased myocardial capillary density. We hypothesized that the physiological pro-angiogenic response to cyanosis in the hypertrophied myocardium is blunted through differential HIF and VEGF-associated signaling. Methods and Results: Newborn rabbits underwent aortic banding and, together with sham-operated littermates, were transferred into a hypoxic chamber (FiO2=0.12) at 3 weeks of age. Control banded or sham-operated rabbits were housed in normoxia. Systemic cyanosis was confirmed (hematocrit, arterial oxygen saturation, and serum erythropoietin). Myocardial tissue was assayed for low oxygen concentrations using a pimonidazole adduct. At 4 weeks of age, HIF-1a and HIF-2a protein levels, HIF-1a DNA-binding activity, and expression of VEGFR-1, VEGFR-2, and VEGF were determined in hypoxic and normoxic rabbits. At 6 weeks of age, left-ventricular capillary density was assessed by immunohistochemistry. Under normoxia, capillary density was decreased in the banded rabbits compared to non-banded littermates. As expected, non-hypertrophied hearts responded to hypoxia with increased capillary density; however, banded hypoxic rabbits demonstrated no increase in angiogenesis. This blunted pro-angiogenic response to hypoxia in the hypertrophied myocardium was associated with lower HIF-2a and VEGFR-2 levels and increased HIF-1a activity and VEGFR-1 expression. In contrast, non-hypertrophied hearts responded to hypoxia with increased HIF-2a and VEGFR-2 expression with lower VEGFR-1 expression. Conclusion: The participation of HIF-2a and VEGFR-2 appear to be required for hypoxia-stimulated myocardial angiogenesis. In infant rabbit hearts with pressure overload hypertrophy, this pro-angiogenic response to hypoxia is effectively uncoupled, apparently in part due to altered HIF-mediated signaling and VEGFR subtype expression.
Management heterogeneity, competitive interaction groups, and firm performance

One of the fundamental problems in strategic management is to map a heterogeneous set of firms in an industry into subsets of firms within which firms are homogeneous in their conduct and performance. The strategic group concept provides an answer to this intriguing question. Researchers in strategic group theory argue that firms within the same strategic group are behaviorally similar and thus tend to compete more fiercely within the group than across groups. In this paper, we focus on the question whether firms within the same group show similar decision-making characteristics. Strategic-choice theorists argue that top management teams in firms have substantial discretion in determining the future strategic contour of firms. Upper-echelon theorists also argue that top managers are the strategists who set the direction of firms and the pace of competition in the industry. Further, they argue that top management team characteristics are an important element that determines the market niche in which a firm competes and the strategic direction a firm follows. Based on these arguments, we expect that there will be a significant link between grouping of firms by the patterns of competitive interactions and grouping of firms by top management team heterogeneity. Moreover, we argue that the closer the TMT heterogeneity of a firm is to the dominant heterogeneity in the competitive interaction group, the better it performs. Copyright © 2000 John Wiley & Sons, Ltd.
Application of Pseudorandom Noise to DPCM

The conventional DPCM compression algorithm has been substantially improved by the substitution of a tapered, noisy quantizer for the usual tapered quantizer. This markedly reduces the visibility of defects caused by granular noise and leak. The quantizer characteristic can then be modified to achieve less slope overload, thus significantly improving image quality.
Partial gastrectomy with gastrojejunal anastomosis including Roux-en-Y reconstruction

In 1881 Billroth performed the first successful partial gastrectomy for cancer. It was Shoemaker in 1911, however, who extended the indication for partial gastrectomy to include benign ulcer disease. For over 30 years thereafter subtotal gastrectomy became an important operation for peptic ulcer. Truncal vagotomy for peptic ulcer was reintroduced by Dragstedt in 1942, and truncal vagotomy with drainage or with partial gastrectomy became the most important ulcer operation in the 1950s and 1960s. In the subsequent three decades gastrectomy has been replaced by increasingly more selective types of vagotomy as the cornerstone in the treatment of duodenal ulcer. Gastric resection is now seldom employed as the sole operation for duodenal ulcer. Antrectomy combined with vagotomy is still a common procedure for duodenal ulcer in the USA. Gastric resection, however, is the standard procedure for benign gastric ulcers and gastric malignancies.
Improved Method for Sectioning Pectoral Spines of Catfish for Age Determination

ABSTRACT A modified low-speed saw provided fast and precise sectioning of catfish pectoral spines for use in aging studies. In one hour, 10–15 spines can be sectioned, the sections mounted, and the annuli counted. Two methods commonly used to section ictalurid pectoral spines are (1) acid decalcification, followed by the use of a razor blade or microtome to slice the softened spines, and (2) cutting hard spines with electric saws. Decalcifying methods are time-consuming, and we had difficulty attaining the proper spine consistency for sectioning when we used decalcification techniques. Electric saws with toothed blades tended to obliterate the first-year annulus at the periphery of the central lumen on spines of channel catfish (Scholl 1968). A low speed saw equipped with two, thin parallel diamond blades was used to section fish fin rays and spines (Shepard and Nichy 1984), but drawbacks are that the preparation is time-consuming and the blades tend to warp. We used a low speed saw with a thick (0.3 mm),...
An analytical study of separated flow about circular cylinders.

Lift and drag coefficients for circular cylinder immersed in time dependent flow analyzed using potential flow model
Quantitative microdialysis of serotonin and norepinephrine: Pharmacological influences on in vivo extraction fraction

The present study was designed to investigate the potential influence of various neuronal processes including uptake, release and metabolism, on the in vivo microdialysis extraction fraction (Ed) of serotonin (5HT) and norepinephrine (NE). Paroxetine administration decreased the Ed of 5HT in the nucleus accumbens from 24 +/- 3 to 18 +/- 0.2% (p < 0.05). Similarly, desipramine infusion reduced the NE Ed from 35 +/- 2 to 26 +/- 1% (p < 0.05). However, perfusion with pargyline or tetrodotoxin had no effect on the Ed of either 5HT or NE. Perfusion with agonists for the 5HT, alpha-adrenergic, D2 and histamine receptors had no effect on the Ed of 5HT. In the same manner, perfusion with the alpha-adrenergic agonists, methoxamine or clonidine, did not affect the Ed of NE. These data are in agreement with experimental results obtained for dopamine in the nucleus accumbens and the theory of quantitative microdialysis which predicts that only changes in the rate of clearance will change Ed of monoamines. These results suggest that, like DA, changes in the Ed for 5HT or NE are indicative of changes in the reuptake of these neurotransmitters. The results also indicate that pharmacological agents which do not affect uptake have no effect on the extraction fraction.
The Environmental Protection Agency Regulates Greenhouse Gas Emissions: Is Anyone Paying Attention?

The promulgation of the Mandatory Reporting of Greenhouse Gases Rule stands as the first step to developing a comprehensive national approach to climate change. However, what role, if any, did interest groups play in the development of this rule? This paper applies Kingdon's multiple streams model as a descriptive framework to analyze interview data for this rule to better understand interest group involvement across all the stages of the rule-making process (rule development, notice and comment phase, and rule finalization). Our research suggests that interest groups were indeed influential throughout the process, but those involved during rule development were clearly at an advantage.
A Note on the Flux-Variance Similarity Relationships for Heat and Water Vapour in the Unstable Atmospheric Surface Layer

Atmospheric surface layer (ASL) experiments over the past 10 years demonstrate that the flux-variance similarity functions for water vapour are consistently larger in magnitude than their temperature counterpart. In addition, latent heat flux calculations using the flux-variance method do not compare as favorably to eddy- correlation measurements when compared to their sensible heat counterpart. These two findings, in concert with measured heat to water vapour transport efficiencies in excess of unity, are commonly used as evidence of dissimilarity between heat and water vapour transport in the unstable atmospheric surface layer. In this note, it is demonstrated that even if near equality in flux-profile similarity functions for heat and water vapour is satisfied, the flux-variance similarity functions for water vapour are larger in magnitude than temperature for a planar, homogeneous, unstably-stratified turbulent boundary-layer flow.
How Undergraduate Students Identify and Utilize Informal Mentors.

After receiving a broad definition of mentoring, students were asked to indicate whether they had mentors and the types of assistance the mentor provided. In the absence of a formal mentoring program and with a decentralized and loosely structured academic advising program, one half of the undergraduate business majors sampled identified faculty members, administrators, parents, friends, relatives, and members of the business community as mentors. We examined the role and identity of informal mentors from an undergraduate perspective and explored the composition and needs of the unmentored student population as well. Implications for practice are discussed.
Future learning environment and impact of ISE

Relevant technologies that can significantly impact education and training are described. The technologies are grouped into four categories: information technology and infrastructure, collaboration technology, modeling and simulation technology, and instructional technology. The synergistic combination of these technologies can dramatically increase the effectiveness of learning. Future learning environment is described in terms of learning objectives, instructional models and technologies. A proposed learning model is presented for preparing engineers to handle the complexities and uncertainties of future high-tech systems. The role of the intelligent synthesis environment (ISE), being developed by NASA, University of Virginia and JPL, in the future learning environment is described.
The Human Bitterness Detection Threshold of Iso-α-acids and Tetrahydro-iso-α-acids in Lager Beer

The human taste thresholds of iso-α-acids (iso) and tetrahydro-iso-α-acids (tetra) were measured in an unhopped lager beer matrix using the ASTM method 1432 protocol. For each compound, 14 volunteers participated in 3 training sessions and 6―13 testing sessions, during which each panelist was presented with a series of six 3-alternative forced-choice tests. Each series was presented in increasing concentration by a factor of 1.5 or 1.3 over the previous dosed sample for iso and tetra, respectively. The individual panelist threshold concentrations were determined as the point on a sigmoidal curve fitted to their percent correct response data where the panelist correctly chose the dosed sample 66% of the time. The group-wise detection threshold was determined as the point on a rank probability plot where 50% of the panelists correctly identified the dosed sample. The group-wise detection thresholds and standard deviations of thresholds for iso and tetra were 7.1 mg/L (4.5―11.2 mg/L) and 2.7 mg/L (0.7―10.0 mg/L), respectively. Threshold data obtained in this experiment were also analyzed using ASTM method 679. Group and individual threshold results were compared across both methods and were not statistically different on all but one testing day.
The pharmacokinetics of maropitant, a novel neurokinin type‐1 receptor antagonist, in dogs

Maropitant is the first NK1 receptor antagonist developed to treat and prevent emesis in dogs; it is administered by subcutaneous (s.c.) injection at 1 mg/kg, or orally (p.o.), in tablet form, at either 2 or 8 mg/kg depending on indication. The absolute bioavailability of maropitant was markedly higher (90.7%) following s.c. injection than after oral administration (23.7% at the 2 mg/kg dose and 37.0% at the 8 mg/kg dose). First-pass metabolism contributes to the low bioavailability of maropitant following oral administration. The difference in bioavailability between the two oral doses reflects the nonlinear kinetics characterizing the disposition of maropitant within the 2-8 mg/kg dose range. Systemic clearance of maropitant following intravenous (i.v.) administration was 970, 995 and 533 mL/h.kg at doses of 1, 2 and 8 mg/kg, respectively. Nonproportional kinetics were observed for p.o. administered maropitant at doses ranging from 2 to 16 mg/kg but dose proportionality was demonstrated at higher doses (20-50 mg/kg). Linearity was also demonstrated following s.c. administration at 0.5, 1 and 2 mg/kg. Maximum plasma drug concentration (Cmax) occurred 0.75 h (tmax) after s.c. administration at 1 mg/kg, and at 1.7 and 1.9 h after oral administration of 8 and 2 mg/kg doses, respectively. The apparent terminal half-life of maropitant was 7.75, 4.03 and 5.46 h after dosing at 1 mg/kg (s.c.), 2 mg/kg (p.o.) and 8 mg/kg (p.o.), respectively. Feeding status had no effect on oral bioavailability. Limited accumulation occurred following once-daily administration of maropitant for five consecutive days at 1 mg/kg (s.c.) or 2 mg/kg (p.o.). At the dose of 8 mg/kg (p.o.) once daily for two consecutive days, the mean AUC(0-24h) (second dose) was 218% that of the first dose value. Urinary recovery of maropitant and its main metabolite was minimal (<1%), thus supporting the evidence that maropitant clearance is primarily hepatic.
Feeding practices of low-income mothers: how do they compare to current recommendations?

Despite a growing consensus on the feeding practices associated with healthy eating patterns, few observational studies of maternal feeding practices with young children have been conducted, especially in low-income populations. The aim of this study was to provide such data on a low income sample to determine the degree to which observed maternal feeding practices compare with current recommendations. Eighty low-income mothers and their preschool children were videotaped at dinner in their homes. Mothers were chosen from a larger study to create a 2 X 2 X 2 design: maternal ethnicity (African American vs. Latina) by child gender by child weight status (healthy weight vs. overweight/obese). Observers coded videotapes for a range of maternal feeding strategies and other behaviors. Many mothers spent considerable time encouraging eating—often in spite of the child’s insistence that he or she was finished. Mothers talked little about food characteristics, rarely referred to feelings of hunger and fullness, and made more attempts to enforce table manners than to teach eating skills. Latina mothers showed higher levels of teaching eating skills and encouraging their children to eat; African American mothers showed higher levels of enforcing table manners and getting children to clear their plates. Mothers of boys used more unelaborated commands and less questions/suggestions than mothers of girls. Finally, compared to mothers of overweight/obese children, mothers of healthy weight children showed higher levels of encouraging eating and lower levels of discouraging eating. Most of the mothers in this study did not engage in feeding practices that are consistent with current recommendations. They did this, despite the fact that they knew they were being observed. These results should be used to inform future research about the motivations behind mothers’ feeding practices and the development of interventions by helping identify areas in greatest need of change.
Pax-3 is necessary for migration but not differentiation of limb muscle precursors in the mouse

The limb muscles of vertebrates are derived from precursor cells that migrate from the lateral edge of the dermomyotome into the limb bud. Previous studies have shown that the paired domain-containing transcription factor Pax-3 is expressed in the limb in cells that are precursors for limb muscles (Williams, B. and Ordahl, C.P. (1994) Development 120, 785-796). In splotch (Pax-3-) embryos, the limb muscles fail to develop and cells expressing Pax-3 are no longer found in the limb. In this paper we have analyzed the role of Pax-3 in the migration and subsequent differentiation of limb muscle precursors. By labeling somites adjacent to the prospective forelimb with the lipophilic dye DiI, we have shown that cells derived from these somites do not migrate into the limbs of splotch mice. The failure of limb muscle precursors to invade the limb in splotch mice is associated with the absence of c-met expression in premigratory cells, together with a change in the morphology of the ventral dermomyotome. In addition, we have shown the lateral half of somites derived from day E9.25 splotch embryos can undergo muscle differentiation when grafted into the limb bud stage 20 chick host embryos. Our results indicate that Pax-3 regulates the migration of limb muscle precursors into the limb and is not required for cells in the lateral somite to differentiate into muscle.
Effects of low speed wind on the recognition/identification and pass-through communication tasks of auditory situation awareness afforded by military hearing protection/enhancement devices and tactical communication and protective systems

AbstractObjective: To investigate the effect of controlled low-speed wind-noise on the auditory situation awareness performance afforded by military hearing protection/enhancement devices (HPED) and tactical communication and protective systems (TCAPS). Design: Recognition/identification and pass-through communications tasks were separately conducted under three wind conditions (0, 5, and 10 mph). Subjects wore two in-ear-type TCAPS, one earmuff-type TCAPS, a Combat Arms Earplug in its ‘open’ or pass-through setting, and an EB-15LE™ electronic earplug. Devices with electronic gain systems were tested under two gain settings: ‘unity’ and ‘max’. Testing without any device (open ear) was conducted as a control. Study sample: Ten subjects were recruited from the student population at Virginia Tech. Audiometric requirements were 25 dBHL or better at 500, 1000, 2000, 4000, and 8000 Hz in both ears. Results: Performance on the interaction of communication task-by-device was significantly different only in 0 mph ...