cssi/SciSciGPT-SciSciNet huggingface dataset:
Prediction of Transient and Steady-State Flexural Fatigue Crack Propagation in Concrete Using a Cyclic R-Curve

Fatigue damage in plain portland cement concrete is a nonlinear process that exhibits two distinct crack stages: a deceleration stage (transient crack growth) and an acceleration stage (steady-state crack growth). In the past, either the transient crack growth stage was completely neglected or was described using a power law that used crack extension as its argument. This works well for constant amplitude loading and for one geometry. However, to extend the fatigue prediction to variable amplitude loading, and also account for size effect, a fatigue crack resistance curve should be obtained so that the bridging stresses behind the crack tip can be calculated. In this paper, a new method has been developed to determine the fatigue crack resistance curve from crack rate and stress intensity data obtained from three point bending single edge notched specimens. The results of this study suggest that the fatigue crack resistance curve has a similar shape to the quasi-static crack resistance curve. Primarily, t...
The mechanism of nucleation and growth from CdGeAs2 glass

Abstract Distinctively different microstructures were obtained depending on the heating rate to which CdGeAs2 glasses were exposed during the devitrification process. Differential scanning calorimetry showed that under very slow heating rates, the single crystallization peak splits into three superimposed exotherms. Quenching from the temperature at which selected features appear on the DSC trace and using X-ray diffraction and transmission electron microscopy interactively, demonstrated the initial formation of a metastable doped precursor germanium crystalline phase. This crystalline structure continued to grow until it could no longer accommodate the impurities, and the transformation terminated. These regions then acted as heterogeneous nucleation sites for the growth of chalcopyrite structured CdGeAs2 with a spherulitic microstructure. The spherulites grew as stacked plates from the nucleation site. At higher temperatures, the metastable germanium structure converted, growing backwards toward the center of each precursor, into the stable chalcopyrite structure, permitted by appropriate ionic diffusion shifting composition toward stoichiometry. At faster heating rates, less of these germanium precursors formed, creating a visually bimodal grain size distribution in the microstructure, as compared to slower heating rates. Using the simplex algorithm, the mechanism and activation energy of each reaction are reported as well as the deconvoluted enthalpies of each transformation.
Congestive heart failure in a patient with systemic hypertension

A 70-year-old man developed hypertension many years previously and had a bout with severe congestive heart failure 4 to 5 years before his death. Autopsy showed congestion and edema characteristic of heart failure, and enlarged heart, and slight focal interstitial left ventricular fibrosis, but only slight to moderate coronary atherosclerosis.
The path of inquiry in mental illness and problem-centered self-description

College students listed the questions they would ask a job applicant after he had described the reasons for his psychiatric hospitalization in either problem-centered (PC) or mental illness (MI) terms. The initial questions asked in response to MI self-description were more past-oriented. MI self-description also induced a greater focus on the conditions of admission and discharge, with questions phrased to imply that the ex-patient was notautonomous in entering and leaving the hospital.
Random convex hulls in a product of balls

The convex hull of a set of points sampled independently and uniformly from the Cartesian product of balls of various dimensions is investigated. Bounds on the asymptotic behavior of the expected combinatorial complexity volume, and mean width are derived when the distribution is held fixed and the sample size approaches infinity. The expected combinational complexity and volume are found to depend (up to constant factors) only on the greatest dimension of any factor ball and the number of balls of that dimension. On the other hand, the expected mean width depends only on the number of balls and the dimensions of the product.
Effects of Two Different Catheter Ablation Techniques on Spectral Characteristics of Atrial Fibrillation

Objectives The aim of this study was to determine the effects of circumferential pulmonary vein ablation (CPVA) and electrogram-guided ablation (EGA) on the spectral characteristics of atrial fibrillation (AF) and the relationship between changes in dominant frequency (DF) and clinical outcome. Background Circumferential pulmonary vein ablation and EGA have been used to eliminate AF. Spectral analysis may identify high-frequency sources. Methods In 84 consecutive patients, CPVA (n = 42) or EGA (n = 42) was performed for paroxysmal (n = 49) or persistent (n = 35) AF. During EGA, complex electrograms were targeted. Lead V1and electrograms from the left atrium and coronary sinus were analyzed to determine the DF of AF before and after ablation. Results The left atrial DF was higher in persistent (5.83 ± 0.86 Hz) than paroxysmal AF (5.33 ± 0.76 Hz, p = 0.03). There was a frequency gradient from the left atrium to the coronary sinus (p = 0.02). Circumferential pulmonary vein ablation and EGA resulted in a similar decrease in DF (18 ± 17% vs. 17 ± 15%, p = 0.8). During a mean follow-up of 9 ± 6 months, the change in DF after CPVA was similar among patients with and without recurrent AF. An acute decrease in DF after EGA was associated with freedom from recurrent AF only in patients with persistent AF (19 ± 14% vs. 3 ± 6%, p = 0.02). Conclusions Both CPVA and EGA decrease the DF of AF, consistent with elimination of high-frequency sources. Whereas the efficacy of EGA is associated with a decrease in DF in patients with persistent AF, the efficacy of CPVA is independent of changes in DF. This suggests that CPVA and EGA eliminate different mechanisms in the genesis of persistent AF.
Cognitive control: preparation of task switching components.

Abstract Task performance often improves when tasks can be prepared in advance. However, the mechanisms that support advance preparation are highly debated. Proceeding under the hypothesis that switch-specific neural activation during advance preparation is the hallmark of controlled processing, this study investigates the behavioral and neural effects of component preparation during task-switching. Toward this end, fMRI was used to observe neural activity during preparation of response rules (RULE task) compared to preparation of stimulus set (PERCEPTUAL task). We predicted that switch-specific activation would be observed for RULE and PERCEPTUAL switching when component preparation was isolated from target-related activation. The results indicated that preparation for both tasks was supported by common regions of activation; however preparation for switches of response rule was supported by switch-specific activation of the anterior cingulate (ACC) and left lateral prefrontal cortex (LPFC). Shift-cost was also eradicated in this condition with enough preparation time, and was associated with an increase in ACC activation. Switches of stimulus set were not marked by specific neural activity during the preparation interval. While the amount of preparation time affected overall performance, PERCEPTUAL task switches did not benefit more from preparation time than task repeats. It was concluded that response rules can be reconfigured pre-target due to the support of ACC–LPFC activation, where preparation of stimulus sets is supported by a general type of configuration common to both components.
Evolutionary drift of the argF and argI genes. Coding for isoenzyme forms of ornithine transcarbamylase in E. coli K12

Considerable genetic drift has occurred during the evolution of the two genes, argF and argl, which individually code for isoenzyme forms of ornithine transcarbamylase in E. coli K12. The use of the experimental protocol described in this work established that between 25-40% of the base pairs in the genes argF and argl have changed since they diverged from a hypothetical ancestral gene. The extent of divergence of the genes was determined by mRNA-DNA hybridization utilizing arginine transducing DNA as a hybridization probe and mRNA prepared in vivo from appropriate bacterial strains and with mRNA synthesized in vitro using template DNA isolated from the specialized transducing phages gammacI857dargl and phi80dargF.
On the use of internal variable constitutive equations in transient forming processes

Abstract Constitutive relations which utilize internal variables to characterize the changing state of a material during a deformation process have been proposed by several investigators in recent years. The internal variable models offer the advantage of extending the range of conditions over which a single material description is applicable at the computational cost of integrating the evolution equations for the internal variables. A method is presented for including a constitutive equation utilizing a single scalar internal variable in a model for transient thermomechanical phenomena. Galerkin's method is used to obtain the finite-element formulation for the time integration of the evolution equation. As an illustration of the technique Hart's model is implemented in a simplified form where the anelastic strain has been neglected leaving only the scalar internal variable. A method for determining material parameters is outlined in the context of a particular material (304 Stainless Steel). The material parameters are determined entirely from data independent of the application. As an application, the process of upset welding is simulated and comparisons of the results are made to experiments and to simulations performed with a viscoplastic material model which neglects strain hardening. Qualitative and quantitative improvements over the strain independent model are noted with only a modest penalty in computational effort for the process modeled.
Resumption of ovarian follicular activity and uterine involution in the postpartum llama

Resumption of ovarian follicle activity and uterine involution was studied in the post partum llama. Thirty-nine adult multiparous llamas were monitored by ultrasonography and analysis of urinary estrone sulfate for 30 d post partum at the La Raya Research Station in Peru. Uterine involution was measured in terms of reduction of length and diameter of both uterine horns. Correlation analysis was used to relate follicle size and concentration of estrone sulfate. Analysis of variance was used to determine rate of uterine involution relative to days post partum. The left ovary was palpated and scanned by Day 3 post partum in contrast to Day 1 post partum for the right ovary. Ovulatory size follicles, 7 mm, were present by Day 7.4 post partum (range 4 to 14 d). Follicle growth was detected as early as Day 4 post partum with follicle size being less during the first follicle wave (7.4 mm) compared to the second and third waves (9 to 10 mm). Concentrations of urinary estrone sulfate were positively related (P<0.05) to follicular size, but to a lesser degree during the first follicle wave (19.4 ng/mg Cr), than to the second wave (25.4 ng/mg Cr). Uterine involution, as measured by diameter, was different between the left (gravid) and right (nongravid) uterine horn (P<0.05) for the 17 d post partum, and was also different from that of control females for the 21 d post partum. Uterine involution was complete in 63% of females by Day 21 post partum.
A Social-Cognitive-Ecological Framework for Understanding the Impact of Exposure to Persistent Ethnic-Political Violence on Children’s Psychosocial Adjustment

In this article, we describe a theoretical framework for understanding how persistent and extreme exposure to ethnic-political conflict and violence interacts with cognitive, emotional, and self processes to influence children's psychosocial adjustment. Three recent strands of theorizing guide our approach. First, we focus on how observational and social learning processes combine to influence the development of social-cognitive structures and processes that affect behavior. Second, we focus on the role of developing self and identity processes in shaping the child's interactions with the world and the consequences of those interactions. Third, we build on the complex systems perspective on development and assume that human development can only be understood accurately by examining how the multiple contexts affecting children and the adults in their lives interact to moderate biosocial factors which predispose individuals to develop in certain directions. We review the recent empirical literature on children's exposure to ethnic-political violence and we apply the social-cognitive-ecological framework to the empirical findings in this literature. Finally, we propose future directions for research and clinical implications derived from this framework.
Monte Carlo simulations of the crystallization of isotactic polypropylene

We model the temperature dependent conformational changes and orientational and translational ordering of isotactic polypropylene melt in the vicinity of its melting temperature. We use the coarse grained second nearest neighbor lattice model, which has previously been shown to properly model the liquid state thermodynamics of this material. Equilibrium Monte Carlo (MC) simulations show the existence of two characteristic temperatures. Above T = 450 K the chains assume standard Gaussian statistics, but below this temperature we find that helix formation is thermodynamically favored even though the melt is still disordered. Both the helix length and fraction of chain monomers involved in helices increase monotonically with decreasing temperature, and below T = 385 K this material undergoes crystallization. Our results are consistent with recent simulations, which suggest that isothermal crystallization is temporally preceded by the formation of a smectic phase: we argue that the helices are long enough under these conditions to support liquid crystallinity. The crystallinity then evolves in these liquid crystalline “droplets”. Further, we can understand the recent results of de Jeu et al. who had found that isotactic polypropylene chains formed a smectic-like phase under the action of a planar shear even at temperatures above the equilibrium melting point. In summary, these findings support the following physical picture: the unusual spinodal decomposition phenomena seen in the early stages of isothermal crystallization, which have been assigned to the formation of small liquid crystal droplets, have equilibrium signatures above the melting point where locally rigid chain sequences become thermodynamically stable. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3453–3460, 2006
Vocal Fold Injection Augmentation with Novielle Voice Gel

Results: 31 patients were prospectively evaluated. The mean age of the cohort was 68 years. Sixtyone percent was male. The diagnoses were 18 unilateral vocal fold paralyses, 4 vocal fold pareses, 9 presbylarynx. The mean VHI at entry was 27 (+/7.4). This improved to a mean VHI of 18 (+/9) at one month postoperatively (p < 0.00) and 19 (+/11) at three months (p=0.00). The mean follow-up time was 93 days. There was no evidence of adverse reaction to the implant or procedurerelated complications.
Continental liquid water cloud variability and its parameterization using Atmospheric Radiation Measurement data

[1] Liquid water path (LWP) variability at scales ranging from roughly 200 m to 20 km in continental boundary layer clouds is investigated using ground-based remote sensing at the Oklahoma site of the Atmospheric Radiation Measurement (ARM) program. Twelve episodes from the years of 1999 to 2001 are selected corresponding to conditions of overcast, liquid water single-layered cloud. In contrast to previous studies of marine boundary layer clouds, variability in cloud-top height in these clouds is comparable to that of cloud base, and most continental clouds appear to be subadiabatic. In agreement with previous studies of marine boundary layer clouds, variations in LWP are well related to the variations in cloud thickness. LWP variability exhibits significantly negative correlation with the static stability of the inversion near cloud top; larger cloud variability is associated with less stable inversions. A previously developed parameterization of LWP variability is extended to account for the differing conditions of continental clouds. The relationship between fluctuations in LWP and cloud thickness suggests that cloud parameterizations treating variations in LWP at these scales should include the effects of subgrid-scale fluctuations in cloud thickness. One such treatment is proposed within the context of a statistical cloud scheme.
Providing time- and space- efficient procedure calls for asynchronous software thread integration

Asynchronous Software Thread Integration (ASTI) provides fine-grain concurrency in real-time threads by statically scheduling (integrating) code from primary threads into secondary threads, reducing the context switching needed and allowing recovery of fine-grain idle time. Unlike STI, ASTI allows asynchronous thread progress.Current ASTI techniques do not support procedure calls in the secondary thread because they lead to timing conflicts during static scheduling. ASTI requires knowing the secondary thread's instruction execution schedule to guide placement of real-time instructions from the primary thread. A secondary thread procedure called from multiple sites will have ambiguous timing at compile time.In this paper we remove this constraint using both procedure inlining and cloning. We present a formal approach to choosing a subset of calls to inline and to remove the timing conflicts in the remaining call sites in an efficient fashion. Excessive inlining and cloning both lead to code size explosion, while poor choices in timing conflict elimination slow program execution. The cloned threads show a significant speedup when compared to non-cloned versions yet have low code expansion. The techniques presented here have been implemented in our post-pass compiler Thrint and demonstrated on a benchmark suite of secondary threads representative of low-end embedded systems.
General retail patronage loyalty as a determinant of consumer outshopping behavior

Consumer outshopping research has shown there are significant, but weak, relationships between consumers' attitudes toward local retailers and the degree to which they shop in local versus outlying areas. An alternative attitude measurement, retail patronage loyalty, is proposed and empirically evaluated. The loyalty scale was shown to be a stronger and more generalizable predictor of consumer outshopping behavior.
In vivo induction of rat hepatic ornithine decarboxylase and plasminogen activator by 12-O-tetradecanoypphorbol 13-acetate

Rapid and substantial elevations in ornithine decarboxylase and plasminogen activator have been linked to tumor promotion in mouse epidermis and in vitro. Systemic administration of 12-O-tetradecanoylphorbol 13-acetate (TPA) rapidly increased both enzymic activities in rat liver. Pretreatment with either cycloheximide or actinomycin D attenuated both enzyme inductions. It is concluded that: (1) systemic TPA rapidly induces plasminogen activator and ornithine decarboxylase activities in rat liver; and (2) both inductions reflect de novo enzyme synthesis.
Calculation of maximum velocity decay in wall jets

Maximum velocity decay in wall jets calculated for comparison with experimental velocity profile
Adapting Triandis's Model of Subjective Culture and Social Behavior Relations to Consumer Behavior

This article develops and tests a framework for the investigation of cultural influences on consumer purchasing behavior by examining the psychological processes that intervene. The model is empirically tested with a camera purchase decision survey in Singapore, Korea, Hong Kong, Australia, and the United States. The data analyzed at the pooled, cultural, and individual difference (i.e., idiocentrism and allocentrism) levels supports the etic nature of the model. In addition, the theory of individualism (idiocentrism) and collectivism (allocentrism) was applied to the model to derive and test specific cross-cultural hypotheses, including the impact of referent past experience and referent expectations and affordability on purchase intentions. At the individual level, it was found that both referent influences and affordability had a stronger influence for the allocentric subsample than for the idiocentric subsample.
Soft- and hard-templated organic salt nanoparticles with the Midas touch: gold-shelled nanoGUMBOS

An emerging thrust in the design of advanced materials is nanoscale functional materials possessing multiple capabilities, such as those possessing a core–shell architecture. Nanoparticles comprising a dielectric core (e.g., silica, polystyrene) and a gold shell are particularly attractive due to the desirable optical (plasmonic) and biocompatibility characteristics of gold. While these materials are bio-inert, they generally present limited tunability. In this regard, a core composed of a solid-state ionic liquid represents an interesting and unexplored alternative for generating unique core–shell architectures. In recent years, we have developed an emergent class of morphology-controlled tailored organic salt particles, so-called GUMBOS (group of materials based on organic salts). GUMBOS are reminiscent of traditional ionic liquids with the important distinction that they possess elevated melting points (generally, from 100 to 250 °C), making possible the fabrication of ambient-stable nanoscale salts of various sizes, compositions, and morphologies by means of a variety of thermal, sonochemical, colloidal, or hard-template synthetic routes. In this work, we advance our recent examination of GUMBOS to demonstrate proof of concept for their use in elaborating novel plasmonic nanostructures by using a seed-mediated growth to generate gold shells atop nanoscale quasi-spherical GUMBOS as well as uni-dimensional GUMBOS nanorods. We present here our general strategy for preparing gold-shelled nanoGUMBOS, alongside systematic monitoring of the evolution of the gold-coating process. We also report on a preliminary investigation of the catalytic properties of the near-infrared absorbing gold-shelled nanorod GUMBOS in the reduction of 4-nitrophenol to 4-aminophenol using sodium borohydride.
Extinction of cocaine-induced place approach in rats: a validation of the "biased" conditioning procedure.

Abstract It has often been demonstrated that when a rat is conditioned in a cue-specific environment that has been repeatedly paired with cocaine injections, it will spend more time in that environment than it does in a saline-paired environment. This behavioral procedure is commonly known as the conditioned place preference (CPP)-test. At present, a firm theoretical understanding of the mechanisms underlying the production of a CPP are unknown. It is insufficient merely to know that a CPP can result after repeated drug pairings. Rather, it is necessary that the procedure is validated within a learning theory framework. The objective of the present study was, therefore, to establish that what is observed in place preference studies was, indeed, conditioning. This was accomplished by determining whether a cocaine-induced increase in time spent in a drug-paired environment was subject to attenuation following extinction trials. Rats were tested for their initial bias in spending more time in one of two stimulus-specific chambers of a place-conditioning apparatus. On four occasions, rats were injected with 2.5 mg/kg cocaine and confined to their less-preferred chamber whereas, on four alternating sessions, they were conditioned with saline (vehicle) in their preferred chamber. Subsequent testing in the nondrugged state revealed that these rats displayed a significant increase in the time spent in their initially least-preferred environment compared to baseline measurements. Following establishment of this cocaine-induced CPP, the rats were injected only with saline and conditioned for an equal number of sessions (i.e., four). The cocaine-induced increase in the time spent was subsequently found to be significantly attenuated in comparison to nonextinction-treated control rats. These results are discussed in terms of operant and Pavlovian models of conditioning.
Hallmark of excellence: research and evidence-based practice as the foundation for quality pediatric nursing.

The hallmark of excellence in pediatric nursing is the use of research and evidence-based practice as the foundation for quality care for children and their families. Creating a culture and an organizational environment focused on quality and safety outcomes leads to improved accountability and excellence in nursing practice.
Optimal policies in a dynamic oligopoly model of international trade

Abstract The paper generalises the static Cournot oligopoly model of international trade to a dynamic context and derives optimal trade policies. It is found that an export subsidy is the optimal instrument for intervention by the domestic country when the domestic and foreign firms compete only in a third market. When domestic consumption is allowed for the optimal policy is a production subsidy. It is found that unlike the static Cournot case, in the dynamic version the reaction curves of both firms shift when a tax/subsidy is imposed.
Batch variance estimators for the median of simulation output

Batching is a well-known technique for estimating the variance of point estimators computed from simulation experiments. The batch statistic variance estimator is simply the (appropriately scaled) sample variance of the original point estimator computed on subsets of data. The sample mean is the most common statistic used to estimate the steady-state mean of a simulation. In this note we show that the sample median has some attractive properties beyond those it has in the independent data setting (e.g., guarding against heavy-tail distributions). Specifically, we show that the sample median loses very little in efficiency for positively correlated output, and that the batch variance estimator of the sample median has comparable bias to that of the sample mean in estimating its asymptotic variance. For the rare case of negatively correlated data, however, the sample median is very inefficient relative to the sample mean. For ''heavy-tail'' distributions the sample median retains its superiority over the sample mean.
Small angle neutron and X-ray scattering from magnetite crystals in magnetotactic bacteria

Abstract Small angel neutron and X-ray scattering were used to study the magnetic and structural properties, respectively, of intracellular magnetite crystals (magnetosomes) in the bacterium, Aquaspirillum magnetotacticum, grown in pure culture. An average of twenty magnetite particles of diameter 400–500 A are arranged in a chain that longitudinally traverses each cell. Behaving like magnetic dipoles, the bacteria orient in the geomagnetic field. Small angle X-ray scattering measurements revealed that bacteria grown in the presence of large amounts of iron contained magnetosomes with diameters averaging approximately 400 A. Those grown under iron-starved conditions contained particles with slightly smaller diameters. The contrast variation technique was used for the small angle neutron scattering measurements in order to establish that a 30% D2O/H2O ratio in the solvent resulted in the maximization of the scattering from the bacterium itself, thus enhancing that from the magnetosomes. Measurements in 30% D2O and an applied field of 25 G confirmed that the scattering from the larger magnetic particles is of ferromagnetic character whereas that from the smaller particles is consistent with super-paramagnetic particles. The static spin correlations were found to be of relatively long range, with dynamical fluctuations corresponding to a distance scale of approximately 50 A.
Ecological dimensions of Appalachian agricultural diversity, 1880–1910

This research uses aggregate statistical sources to describe agricultural diversity in a 31 county area of Appalachian Kentucky over the period 1880–1910. In particular, it considers the distribution and duration of forest farming in this region. It examines the causes of agricultural diversity by testing a series of hypotheses conceptually based in ecological theory. For 1880, counties differed in the degree to which they had the characteristics expected for forest farming. This variation was geographically patterned. While there was still geographical variation in county agricultural characteristics in 1910, sufficient change had occurred so that none of the counties continued to closely conform to the pattern expected for forest farming. Variation and change in county agricultural characteristics were found to be related to population density and growth, soil quality, the presence of railroads, and the development of commercial coal mining.
ISOMORPHISM OF COMPLETE LOCAL NOETHERIAN RINGS AND STRONG APPROXIMATION

About a year ago Angus Macintyre raised the following question. Let A and B be complete local noetherian rings with maximal ideals m and n such that A/m" is isomorphic to B/n n for every n. Does it follow that A and B are isomorphic? We show that the answer is yes if the residue field is algebraic over its prime field. The proof uses a strong approximation theorem of Pfister and Popescu, or rather a variant of it, which we obtain by a method due to Denef and Lipshitz. Examples by Gabber show that the answer is no in general.
Orbit computation with the Vinti potential and universal variables

When the Vinti potential and spheroidal coordinates are used in the solution of the equations of motion of an Earth satellite, the Hamilton-Jacobi differential equation is separable, permitting computation of the free flight path in closed form. If the parameters are chosen to include the effect of the Jz and Js terms of the Earth's gravitational potential, the Vinti potential also allows for a major part of the effect of the term in J4. The model can serve as an improved reference orbit in perturbation theory, or it can be used to compute moderately accurate trajectories (extremely accurate over short time intervals) with a considerable saving of machine time over numerical integration. The development in universal variables is valid for orbits of eccentricity greater than unity as well as for periodic orbits. The main purpose of this paper is to generalize the results of Vinti and others to include the nonperiodic cases. Included is a description of a tested method for practical calculation of trajectories and a numerical example for illustration.
The Political Science of E. H. Carr

If peace and security are the earmarks of a successful foreign policy, the foreign policies pursued since the end of the first World War by the great Western powers were certainly less successful than any pursued by these powers since the end of the Napoleonic Wars. To say this, of course, is only to state the obvious. That the succession of failures is rooted in a marked decline in the political intelligence of the Western world is less obvious. Yet the recognition of that relationship is decisive for the understanding of the disease which holds the modern state system in its grip.
Ubiquitin C-terminal Hydrolase-L1 Protects Cystic Fibrosis Transmembrane Conductance Regulator from Early Stages of Proteasomal Degradation

ΔF508 cystic fibrosis transmembrane conductance regulator (CFTR) degradation involves ubiquitin modification and efficient proteasomal targeting of the nascent misfolded protein. We show that a deubiquitinating enzyme, ubiquitin C-terminal hydrolase-L1 (UCH-L1), is highly expressed in cystic fibrosis (CF) airway epithelial cells in vitro and in vivo. We hypothesized that the elevation in UCH-L1 in CF cells represents a cellular adaptation to counterbalance excessive proteasomal degradation. The bronchial epithelial cell lines IB3-1 (CF, high UCH-L1 expression) and S9 (non-CF, low UCH-L1 expression) were transiently transfected with wild type (WT) or ΔF508 CFTR, WT UCH-L1 or small interfering RNA-UCH-L1, and a variety of ubiquitin mutants. We observed a positive correlation between UCH-L1 expression and steady state levels of WT- or ΔF508-CFTR, and this stabilizing effect was confined to the early stages of CFTR synthesis. Immunolocalization of UCH-L1 by confocal microscopy revealed a partial co-localization with a ribosomal subunit and the endoplasmic reticulum. The UCH-L1-associated increase in CFTR levels was correlated with an increase in ubiquitinated CFTR (CFTR-Ub). Co-transfection with mutant ubiquitins and treatment with proteasome inhibitors suggested that UCH-L1 was reducing the proteasomal targeting of CFTR during synthesis by shortening conjugated polyubiquitin chains. Although not sufficient by itself to rescue mutant CFTR therapeutically, the elevation of UCH-L1 and its effect on CFTR processing provides insight into its potential roles in CF and other diseases.
Probing the Two-Exciton Manifold of Light-Harvesting Antenna Complexes Using Femtosecond Four-Wave Mixing

Two femtosecond four-wave-mixing techniques carried out using the photon echo pulse sequence with positive or negative time delays are shown to provide a direct probe for two-exciton dynamics in light-harvesting antennae of photosynthetic bacteria and green plants. The spectroscopic signatures of intramolecular and interaction-induced (intermolecular) two-exciton states are analyzed using a collective excitonic oscillator representation of the nonlinear optical response.
APLA: Indexing Arbitrary Probability Distributions

The ability to store and query uncertain information is of great benefit to databases that infer values from a set of observations, including databases of moving objects, sensor readings, historical business transactions, and biomedical images. These observations are often inexact to begin with, and even if they are exact, a set of observations of an attribute of an object is better represented by a probability distribution than by a single number, such as a mean. In this paper, we present adaptive, piecewise-linear approximations (APLAs), which represent arbitrary probability distributions compactly with guaranteed quality. We also present the APLA-tree, an index structure for APLAs. Because APLA is more precise than existing approximation techniques, the APLA-tree can answer probabilistic range queries twice as fast. APLA generalizes to multiple dimensions, and the APLA-tree can index multivariate distributions using either one-dimensional or multidimensional APLAs. Finally, we propose a new definition of k-NN queries on uncertain data. The new definition allows APLA and the APLA-tree to answer k-NN queries quickly, even on arbitrary probability distributions. No efficient k-NN search was previously possible on such distributions.
Arabidopsis AtGPAT1 , a Member of the Membrane-Bound Glycerol-3-Phosphate Acyltransferase Gene Family, Is Essential for Tapetum Differentiation and Male Fertility

Membrane-bound glycerol-3-phosphate acyltransferase (GPAT; EC 2.3.1.15) mediates the initial step of glycerolipid biosynthesis in the extraplastidic compartments of plant cells. Here, we report the molecular characterization of a novel GPAT gene family from Arabidopsis, designated AtGPAT. The corresponding polypeptides possess transmembrane domains and GPAT activity when expressed heterologously in a yeast lipid mutant. The functional significance of one isoform, AtGPAT1, is the focus of the present study. Disruption of the AtGPAT1 gene causes a massive pollen development arrest, and subsequent introduction of the gene into the mutant plant rescues the phenotype, illustrating a pivotal role for AtGPAT1 in pollen development. Microscopic examinations revealed that the gene lesion results in a perturbed degeneration of the tapetum, which is associated with altered endoplasmic reticulum profiles and reduced secretion. In addition to the sporophytic effect, AtGPAT1 also exerts a gametophytic effect on pollen performance, as the competitive ability of a pollen grain to pollinate is dependent on the presence of an AtGPAT1 gene. Deficiency in AtGPAT1 correlates with several fatty acid composition changes in flower tissues and seeds. Unexpectedly, however, a loss of AtGPAT1 causes no significant change in seed oil content.
Potentiation of Adrenergic Venomotor Responses in Dogs by Cardiac Glycosides

Acetylstrophanthidin, 0.3 to 10 µg/ml, caused contraction of helical strips of the dog cutaneous vein in an organ bath at 37°C. A latent period of 12 to 60 minutes preceded the contraction. During this time, the vein exhibited a progressive increase in response to transmural electric stimulation and added norepinephrine. As the dose of acetylstrophanthidin was increased, the latent period shortened and the increased response during the latent period was potentiated. When the contraction caused by 10 µg/ml was maximal, no additional contraction occurred with electric stimulation; the response to electric stimulation was only partially restored by the repeated washing out of the drug, despite relaxation of the strip to almost base-line tension. Since transmural electric stimulation causes contraction by release of tissue catecholamines, these experiments demonstrate that digitalis glycosides sensitize the cutaneous veins of the dog to adrenergic stimulation. This was confirmed in dogs anesthetized with pentobarbital. Intravenous injections of acetylstrophanthidin and digoxin, in doses too small (12.5 to 15.5 µ/kg) to cause direct constriction of the lateral saphenous vein, potentiated the constriction of this vein caused by electric stimulation of the lumbar sympathetic chain.
PARTIAL RESULT ON HADWIGER'S CONJECTURE

Let D = (d1, d2, …, dn) be a graphic sequence with 0 ≤ d1 ≤ d2 ≤ ⋯ ≤ dn. Any simple graph G with D its degree sequence is called a realization of D. Let R[D] denote the set of all realizations of D. We say that D is H-free if no graph in R[D] contains H as an induced subgraph. In this paper, we prove that Hadwiger's Conjecture is true for graphs whose degree sequences are claw-free or -free.
Median filtering as a sudden onset criterion to separate sinus tachycardia from ventricular tachycardia

Because the use of absolute rate alone to distinguish sinus tachycardia (ST) from ventricular tachycardia (VT) lacks precision, rate variation algorithms including sudden onset have been proposed to improve the detection of pathological tachycardias by implantable antitachycardia devices. In this study, a median filtering algorithm was designed, tested, and compared to these established algorithms using identical data. Onset of ST during exercise and during VT was analyzed for 50 cases each. Fixed-interval change and percent change of cardiac cycles were compared as criteria for sudden onset. Optimal performance of the five-cycle median filter was achieved using a threshold of 25% change in median ventricular rate. It successfully differentiated ST from paroxysmal VT with a sensitivity of 92% and specificity of 96%. Median filtering appears to yield better performance when compared to previously proposed onset algorithms for VT identification. >
Regulation of c-Jun N-Terminal Kinase by MEKK-2 and Mitogen-Activated Protein Kinase Kinase Kinases in Rheumatoid Arthritis

The mitogen-activated protein kinase (MAPK) c-Jun N-terminal kinase (JNK) is a critical regulator of collagenase-1 production in rheumatoid arthritis (RA). The MAPKs are regulated by upstream kinases, including MAPK kinases (MAPKKs) and MAPK kinase kinases (MAP3Ks). The present study was designed to evaluate the expression and regulation of the JNK pathway by MAP3K in arthritis. RT-PCR studies of MAP3K gene expression in RA and osteoarthritis synovial tissue demonstrated mitogen-activated protein kinase/ERK kinase kinase (MEKK) 1, MEKK2, apoptosis-signal regulating kinase-1, TGF-β activated kinase 1 (TAK1) gene expression while only trace amounts of MEKK3, MEKK4, and MLK3 mRNA were detected. Western blot analysis demonstrated immunoreactive MEKK2, TAK1, and trace amounts of MEKK3 but not MEKK1 or apoptosis-signal regulating kinase-1. Analysis of MAP3K mRNA in cultured fibroblast-like synoviocytes (FLS) showed that all of the MAP3Ks examined were expressed. Western blot analysis of FLS demonstrated that MEKK1, MEKK2, and TAK1 were readily detectable and were subsequently the focus of functional studies. In vitro kinase assays using MEKK2 immunoprecipitates demonstrated that IL-1 increased MEKK2-mediated phosphorylation of the key MAPKKs that activate JNK (MAPK kinase (MKK)4 and MKK7). Furthermore, MEKK2 immunoprecipitates activated c-Jun in an IL-1 dependent manner and this activity was inhibited by the selective JNK inhibitor SP600125. Of interest, MEKK1 immunoprecipitates from IL-1-stimulated FLS appeared to activate c-Jun through the JNK pathway and TAK1 activation of c-Jun was dependent on JNK, ERK, and p38. These data indicate that MEKK2 is a potent activator of the JNK pathway in FLS and that signal complexes including MEKK2, MKK4, MKK7, and/or JNK are potential therapeutic targets in RA.
Off-Chip Control Flow Checking of On-Chip Processor-Cache Instruction Stream

Control flow checking (CFC) is a well known concurrent checking technique for ensuring that a program's instruction execution sequence follows permissible paths. Almost all CFC techniques require direct access to the CPU-cache bus, meaning that the checking hardware (generally called a watchdog processor (WP)) has to be on-chip. However, an on-chip WP directly accessing the CPU-cache bus has a few disadvantages chief among them being that it will use up appreciable chip real estate of a commodity processor, but may be unnecessary in most environments that do not have significant transient error rates. On the other hand, if an off-chip CFC technique can be developed that imposes minor hardware overheads on the processor chip, then such a WP can be plugged onto the external system bus when needed for concurrent checking, and will have very little of the disadvantages of on-chip WPs. Such an off-chip WP, however, is not generally be able to monitor all instructions due to the bandwidth difference between the CPU bus and the system or memory bus. The authors present techniques that allow generally effective off-chip CFC using partial access to the instruction execution stream that respects the CPU/system bus bandwidth factor (ratio) K, and still achieve reasonable block-level instruction error coverage ranging from 70-80% for K = 5 to about 94% for a K = 2. Furthermore, our experimental results show that the program-level error coverage is almost 100% even for K = 5 (i.e., the authors almost always detect the presence of an instruction error in a program sooner or later before it completes execution, which is useful for fail-safe operation), underscoring the efficacy of our methods
Constituencies and Preferences in International Bargaining

>> Previous formal models of two-level games, which try to determine whether a domestic ratification constraint provides an executive with bargaining leverage in international negotiations, pay little attention to the exact nature of the executive’s constituency and the source of the constraint. The author uses a gametheoretic model to show that an executive with a national constituency such as a nationally elected president benefits by being constrained. An executive with a constituency distinct from that of the ratifying legislators, however, is worse off under greater constraints, when the constraints come from constituencies other than his or her own. This can occur, for instance, in a minority or coalition parliamentary government consisting of parties with different and in fact opposing constituencies. Testable hypotheses are derived on the effect of the party composition of the legislature on the executive’s constraint.
Diversity of the P2 protein among nontypeable Haemophilus influenzae isolates.

Abstract The genes for outer membrane protein P2 of four nontypeable Haemophilus influenzae strains were cloned and sequenced. The derived amino acid sequences were compared with the outer membrane protein P2 sequence from H. influenzae type b MinnA and the sequences of P2 from three additional nontypeable H. influenzae strains. The sequences were 76 to 94% identical. The sequences had regions with considerable variability separated by regions which were highly conserved. The variable regions mapped to putative surface-exposed loops of the protein.
Retinoid-Induced Modulation of Immunoglobulin M Secretion by Bovine Mononuclear Leukocytes In Vitro

Effects of trans and cis isomers of retinol and retinoic acid on IgM secretion by bovine peripheral blood mononuclear leukocytes were evaluated in vitro. Mononuclear leukocyte cultures that were unstimulated or stimulated by pokeweed mitogen were supplemented with isomers of retinol and retinoic acid at 10(-10) to 10(-6) M. Concentrations of polyclonal IgM in supernatants from 14-d cultures were measured by an ELISA. Cultures stimulated by pokeweed mitogen consistently secreted more IgM than parallel, unstimulated cultures. Retinoid supplementation did not affect basal IgM secretion by unstimulated cultures. However, each retinoid affected IgM secretion by cultures stimulated by mitogen. The nature of the effect was dependent on the concentration of the specific retinoid. All-trans-retinoic acid enhanced secretion at 10(-10) M and inhibited secretion at 10(-6) M. The other retinoids, however, did not inhibit IgM secretion at any concentration. Each retinoid enhanced IgM secretion at one or more concentrations, although enhancement was produced by much lower concentrations of retinoic acid isomers than retinol isomers. These results indicate that retinol and retinoic acid modulate polyclonal IgM secretion by cultures of bovine mononuclear leukocytes stimulated by mitogen. Future research will determine which subsets of the mononuclear leukocyte population are affected and whether trans-retinoic acid is the metabolite that produces these effects.
A Brassinosteroid-Insensitive Mutant in Arabidopsis thaliana Exhibits Multiple Defects in Growth and Development

Brassinosteroids are widely distributed plant compounds that modulate cell elongation and division, but little is known about the mechanism of action of these plant growth regulators. To investigate brassinosteroids as signals influencing plant growth and development, we identified a brassinosteroid-insensitive mutant in Arabidopsis thaliana (L.) Henyh. ecotype Columbia. The mutant, termed bri1, did not respond to brassinosteroids in hypocotyl elongation and primary root inhibition assays, but it did retain sensitivity to auxins, cytokinins, ethylene, abscisic acid, and gibberellins. The bri1 mutant showed multiple deficiencies in developmental pathways that could not be rescued by brassinosteroid treatment including a severely dwarfed stature; dark green, thickened leaves; males sterility; reduced apical dominance; and de-etiolation of dark-grown seedlings. Genetic analysis suggests that the Bri1 phenotype is caused by a recessive mutation in a single gene with pleiotropic effects that maps 1.6 centimorgans from the cleaved, amplified, polymorphic sequence marker DHS1 on the bottom of chromosome IV. The multiple and dramatic effects of mutation of the BRI1 locus on development suggests that the BRI1 gene may play a critical role in brassinosteroid perception or signal transduction.