cssi/SciSciGPT-SciSciNet huggingface dataset:
An extracellular MRI polymeric contrast agent that degrades at physiological pH.

Macromolecular contrast agents have the potential to assist magnetic resonance imaging (MRI) due to their high relaxivity, but are not clinically useful because of toxicity due to poor clearance. We have prepared a biodegradable ketal-based polymer contrast agent which is designed to degrade rapidly at physiological pH by hydrolysis, facilitating renal clearance. In vitro, the agent degraded more rapidly at lower pH, with complete fragmentation after 24 h at pH 7.4. In vitro relaxivity measurements showed a direct correlation between molecular weight and relaxivity. We compared our polymer contrast agent with commercially available Magnevist in vivo by MRI imaging, as well as measuring the Gd concentration in blood. Our results show that our polymer contrast agent gives a higher contrast and intensity in the same organs and areas as Magnevist and is cleared from the blood at a similar rate. We aim to improve our polymer contrast agent design to develop it for use as a MRI contrast agent, and explore its u...
Low-let alternatives to particle irradiation

Abstract Two putative advantages are described for high-LET irradiation as compared to electron and photon therapy: biological and physical. The latter relates to the better dose distribution to be obtahwd by high-LET irradiation. Basic to this, however, are more precise tumor localization, definition of tissue inhomogeneities and precision target-volume definition far beyond the current state of the art. Such improved target-volume definition will indubitably allow precision therapy with low-LET irradiation to be developed also. Low-LET irradiation, especially utilizing high-energy photon and electron beams, can achieve acceptably good physical dose distributions tailored to the target volume as it can be defined at present. Typical examples are dose distributions for treatment of pelvic, abdominal, and head and neck tumors. The authors conclude that the biologic, rather than the physical, advantage of high-LET irradiation must justify its clinical use.
Quantum Monte Carlo for Ab Initio calculations of energy-relevant materials

Humanity faces one of its greatest challenges in the move from fossil-fuel based energy sources to alternative sources that do not produce greenhouse gases. New materials design is an important facet of the overall solution, since designed materials have the potential to increase efficiency in areas ranging from solar electricity generation to energy storage and distribution technologies. In that context, it is vital to be able to predict the properties of materials from basic physical principles. While traditional electronic structure techniques such as the ubiquitous density functional theory (DFT) are very important in this goal, there are many cases where current implementations of DFT fail in a design-important way. Among other solutions, quantum Monte Carlo techniques have emerged as a practical way to obtain predictive power for challenging materials. This perspective highlights some recent advances in this field, concentrating in particular on the effect that quantum Monte Carlo methods have and will have on our energy challenge. © 2013 Wiley Periodicals, Inc.
Behavioral effects of introducing pied tamarin (Saguinus bicolor) to black howler monkey (Alouatta caraya) and white-faced saki (Pithecia pithecia) in a zoological park.

Mixed-species primate exhibits are becoming more common in zoological parks as a means to display a diverse array of animals both more naturalistically and with more economy of space. Here, we describe behavioral changes during the introduction process of a pair of pied tamarins (Saguinus bicolor) to an established group of black howler monkeys (Allouatta caraya) and white-faced saki monkeys (Pithecia pithecia). Data were collected during six phases, representing introductions among the various species and to exhibit space and off-exhibit holding. The pied tamarins were consistently the most active of the three species. Although activity levels of the howler and saki monkeys remained constant throughout, that of the tamarins declined as the introduction progressed. Several episodes of aggression between the tamarins and the sakis were observed, but did not coincide with patterns predicted by previous intra-specific introductions. The three-species mix remained stable for several months; however, escalating aggression ultimately led to the removal of the sakis from the mixed-species exhibit. Despite our mixed results, we contend that only through continued trials, coupled with careful and systematic monitoring, can we ultimately identify stable mixes of species. Am. J. Primatol. 70:505–509, 2008. © 2008 Wiley-Liss, Inc.
Tool or Science? GIS, Technoscience, and the Theoretical Turn

(1997). Tool or Science?GIS, Technoscience, and the Theoretical Turn. Annals of the Association of American Geographers: Vol. 87, No. 2, pp. 363-372.
Restriction fragment length polymorphism analysis in ankylosing spondylitis.

Abstract We utilized the technique of restriction fragment length polymorphism (RFLP) analysis in order to examine class I major, histocompatibility complex genes in 52 Alabama ankylosing spondylitis patients and 107 local control subjects. A 9.2-kilobase Pvu II RFLP was identified using the class I-specific B7 cDNA probe pDP001 that was closely associated with ankylosing spondylitis, most specifically with peripheral joint (including shoulder and hip) involvement. This fragment is associated with human leukocyte antigen A3 and A9 alleles, and segregation analysis in 11 multiplex families showed the RFLP to frequently segregate independently of B27 haplotypes. Two more recent studies have not confirmed the association of the 9.2-kilobase Pvu II RFLP with ankylosing spondylitis per se , believed to be due to clinical and possibly genetic differences between the patient groups studied. These data strongly suggest at least one other major histocompatibility complex class I gene to be operative in predisposition to or modification of ankylosing spondylitis.
PLATELET ASSOCIATED PROTEINS AFTER RUBELLA RE-VACCINATION

Top of pageAbstract Rubella revaccination (RA 27/3-Behringwerke, FRG) was given to 20 women (mean age 20 y) in order to study the effect of recurrent infection on the platelet associated (PA-) IgG, IgM, and C3. An antiglobulin consumption assay in a micro-ELISA technique was used at day 0,5,10,20, and 30. We observed neither thrombocytopenia nor adverse reactions on the vaccination. The rubella Ab titer rose from 1:24 to 1:28 (HHT, geometric mean). The starting/highest levels (mean ± SD) were: PAIgG 6.5±4.3/12.2±9.0 (day 20 p.v.), PAIgM 4.7±2.6/13.3±9.7 (day 10 p.v.), PAC3, 2.0± .7/5.0±3.4 (day 20 p.v.). Using the paired t-test the differences were significant (p < 0.005). The increase of platelet associated proteins did not reach levels found in acute ITP, but those seen in acute paediatric infection. Some of these proteins may represent Rubella specific immune complexes which have been demonstrated by others in sera of revaccinees at the appropriate times. In turn our data present another hint on a physiological role of the thrombocyte in removing immune complexes from the circulation. Supported by DFG grant Fo 116/2-1
Investigation of the electronic distribution in the octahedral sites of solid C60 through the 260 K orientational phase transition

Abstract We have investigated the electronic distribution in the octahedral sites of solid C 60 through the 260 K orientational phase transition using temperature-dependent positron lifetime measurements on single crystals. In addition to a gradual temperature-dependent change in positron lifetime, we observe a sharp discontinuity at 260 K, whose size is consistent with that expected from the volume change at the transition. We also examined bulk atmospheric contamination effects on solid C 60 . Samples exposed only to air show no detectable positron lifetime change, but a slight change is observed in samples exposed to both air and light.
MuSA.RT: music on the spiral array. real-time

We present MuSA.RT, Opus 1, a multimodal interactive system for music analysis and visualization using the Spiral Array model. Real-time MIDI input from a live performance is processed, analyzed and mapped to the 3D model, revealing tonal structures such as pitches, chords and keys. A user can concurrently navigate through the Spiral Array space using a gamepad or set the camera control to automatic pilot. The interaction among and concurrent processing of the different data streams is made possible through the Modular Flow Scheduling Middleware.
Concurrent quantification of tissue metabolism and blood flow via 2H/31P NMR in vivo. I. Assessment of absolute metabolite quantification.

In a series of three papers, we demonstrate and validate an approach for concurrent absolute quantification in situ of blood flow and energy metabolism with a modification of the NMR method for absolute concentration determination put forth by Thulborn and Ackerman [J. Magn. Reson. 55, 357 (1983)] and later expanded upon by Tofts and Wray. In this first paper of the series, we briefly review the theoretical basis for the concentration measurement and present, for the first time, a successful paired validation of metabolite quantification via 31P surface-coil NMR through corroborative in vitro enzymatic assays. The paired radiolabeled microsphere validation of blood flow measurement via 2H surface-coil NMR employing D2O as a freely diffusible tracer and the concurrent determination of blood flow and energy metabolism in a septic rat model are presented in the accompanying second and third paper to complete the series. In this article a classical RF tank circuit is employed to describe the effect of conductive sample loading on the NMR receiver by considering its apparent series resistance. It is shown in an easily visualized generalizable manner that the effect of sample loading on the observed NMR signal intensity can be accounted for quantitatively by monitoring changes in 90 degrees pulse width at constant power at a fixed reference point, i.e., Ssample = Sphantom (PW90phantom/PW90sample). In a series of paired experiments the absolute concentrations of high energy phosphates obtained from resting rat leg muscle (n = 4) in situ (NMR) and in vitro (enzymatic) were determined as follows: [PCr]NMR = 17.2 +/- 0.8 SD, [PCr]enzymatic = 17.3 +/- 2 SD, [ATP]NMR = 5.1 +/- 0.8 SD, [ATP]enzymatic = 5.0 +/- 0.2 SD mmol/kg tissue wet wt. Results of these two independent methods of concentration determination were not statistically different (P = 0.94 and P = 0.74 respectively) and serve to rigorously validate the Thulborn approach for absolute quantification of phosphorous metabolites in situ via NMR. Furthermore, these results strongly suggest that ATP and PCr in resting rat leg muscle under normal physiologic conditions are 100% NMR visible. The free cytosolic [ADP]NMR was estimated from the creatine kinase reaction equilibrium expression to be 0.022 +/- 0.003 SD mmol/kg tissue wet wt.
A83543A-D, unique fermentation-derived tetracyclic macrolides

Abstract A multi-factored complex of structurally-unique macrolides was isolated from culture broths of a new species of Saccharopolyspora. The core structure consists of a 5,6,5-cis-anti-trans-tricyclic ring system fused to a 12-membered macrocyclic lactone, which is further substituted by an amino- and a neutral sugar.
Estimation of treatment effects in randomized trials with non‐compliance and a dichotomous outcome

Summary. We propose a class of estimators of the treatment effect on a dichotomous outcome among the treated subjects within covariate and treatment arm strata in randomized trials with non-compliance. Recent papers by Vansteelandt and Goetghebeur, and Robins and Rotnitzky have presented consistent and asymptotically linear estimators of a causal odds ratio, which rely, beyond correct specification of a model for the causal odds ratio, on a correctly specified model for a potentially high dimensional nuisance parameter. In this paper we propose consistent, asymptotically linear and locally efficient estimators of a causal relative risk and a new parameter--called a switch causal relative risk-which relies only on the correct specification of a model for the parameter of interest. Our estimators are always consistent and asymptotically linear at the null hypothesis of no-treatment effect, thereby providing valid testing procedures. We examine the finite sample properties of these instrumental-variable-based estimators and the associated testing procedures in simulations and a data analysis of decaffeinated coffee consumption and miscarriage.
The Origin of Fibroblasts and Mechanism of Cardiac Fibrosis

Fibroblasts are at the heart of cardiac function and are the principal determinants of cardiac fibrosis. Nevertheless, cardiac fibroblasts remain poorly characterized in molecular terms. Evidence is evolving that the cardiac fibroblast is a highly heterogenic cell population, and that such heterogeneity is caused by the distinct origins of fibroblasts in the heart. Cardiac fibroblasts can derive either from resident fibroblasts, from endothelial cells via an endothelial-mesenchynmal transition or from bone marrow-derived circulating progenitor cells, monocytes and fibrocytes. Here, we review the function and origin of fibroblasts in cardiac fibrosis.
Excision of thymine and 5-hydroxymethyluracil by the MBD4 DNA glycosylase domain: structural basis and implications for active DNA demethylation

The mammalian DNA glycosylase--methyl-CpG binding domain protein 4 (MBD4)--is involved in active DNA demethylation via the base excision repair pathway. MBD4 contains an N-terminal MBD and a C-terminal DNA glycosylase domain. MBD4 can excise the mismatched base paired with a guanine (G:X), where X is uracil, thymine or 5-hydroxymethyluracil (5hmU). These are, respectively, the deamination products of cytosine, 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC). Here, we present three structures of the MBD4 C-terminal glycosylase domain (wild-type and its catalytic mutant D534N), in complex with DNA containing a G:T or G:5hmU mismatch. MBD4 flips the target nucleotide from the double-stranded DNA. The catalytic mutant D534N captures the intact target nucleotide in the active site binding pocket. MBD4 specifically recognizes the Watson-Crick polar edge of thymine or 5hmU via the O2, N3 and O4 atoms, thus restricting its activity to thymine/uracil-based modifications while excluding cytosine and its derivatives. The wild-type enzyme cleaves the N-glycosidic bond, leaving the ribose ring in the flipped state, while the cleaved base is released. Unexpectedly, the C1' of the sugar has yet to be hydrolyzed and appears to form a stable intermediate with one of the side chain carboxyl oxygen atoms of D534, via either electrostatic or covalent interaction, suggesting a different catalytic mechanism from those of other DNA glycosylases.
Water interaction differences determine the relative energetic stability of the polyproline II conformation of the alanine dipeptide in aqueous environments.

Although subsequent studies have provided extensive support for the 1968 Tiffany and Krimm proposal (Biopolymers 6, 1379) that the polyproline II (PPII) conformation is a significant component of the structure of unordered polypeptide chains, two issues are still not fully resolved: the PPII persistence length in a chain and the source of its relative stability with respect to the β-conformation. We examine the latter question by studying the B97-D/6-31++G** energy, in the absence and presence of a reaction field, of the alanine dipeptide hydrated by various amounts of explicit waters and resolving this into its three components: the energies of the individual solvated peptides and water structures plus the interaction energy involving them. We find that the relative stability of the PPII conformation is determined mainly by the difference in the interaction energies of the water structures in the near-peptide layers. © 2012 Wiley Periodicals, Inc. Biopolymers 97: 789–794, 2012.
A unique requirement for the leukotriene B4 receptor BLT1 for neutrophil recruitment in inflammatory arthritis.

Neutrophil recruitment into tissue plays an important role in host defense and disease pathogenesis, including the inflammatory arthritides. A multitude of diverse chemoattractants have been implicated in neutrophil recruitment, suggesting that they have overlapping functions in mediating this critical biological response. However, here we demonstrate a unique, non-redundant role for the leukotriene B4 receptor BLT1 in mediating neutrophil recruitment into the joint in the K/BxN mouse model of inflammatory arthritis. We demonstrate that neutrophil expression of BLT1 was absolutely required for arthritis generation and chemokine production in this model, and that specific BLT1 inhibition reversed established disease. Adoptive transfer of wild-type (WT) neutrophils restored arthritis and chemokine production in BLT1−/− mice. Surprisingly, the primary effect of the transferred WT neutrophils into BLT1−/− mice was to promote the entry of endogenous BLT1−/− neutrophils into the joints of these mice. However, continued joint inflammation was dependent on the presence of WT neutrophils, indicating an ongoing specific requirement for BLT1-activated neutrophils in mediating BLT1−/− neutrophil recruitment by other chemoattractants. These experiments demonstrate that neutrophil BLT1 functions in a novel and essential non–cell-autonomous manner to enable the recruitment of additional neutrophils not expressing this receptor, thereby amplifying the inflammatory response in autoantibody-induced arthritis.
An evaluation of the historical exposures of mechanics to asbestos in brake dust.

This article presents a historical analysis of published data regarding the exposure of brake mechanics to asbestos as a result of doing brake work. Concerns about this possible hazard were first raised in the late 1960s. This analysis focuses on 30 years of data collected during the brake repair event (e.g., a brake job) and 8-hour time-weighted average (TWA) personal samples. A brake job TWA represents the average concentration a mechanic experienced during brake servicing, rather than throughout the workday, and an 8-hour TWA represents the average airborne concentration of asbestos for the entire workday (which would involve brake work and other activities). Nearly 200 brake job and 8-hour TWA airborne asbestos samples were analyzed to assess how asbestos concentrations varied by type of vehicle serviced, country in which mechanics worked, time period, and brake-cleaning method. To facilitate comparisons, brake job TWAs were converted to estimated 8-hour TWAs using the durations and number of brake jo...
Carcinogenesis, apoptosis and cell proliferation

Biological agents, especially viruses, have been linked to the carcinogenesis process in major human cancers, especially lymphomas (retroviruses), hepatocarcinomas (hepatitis viruses) and carcinomas of the female genital organs (papilloma viruses). Chronic infection and inflammation have long been suspected to play a role in human carcinogenesis. Helicobacter pylori is the first bacterial infection recognized as a human carcinogen, essentially on the basis of epidemiologic al evidence of causality1. Contrary to most other recognized human carcinogens, experimental evidence of carcinogenesis is lacking. As a consequence, mechanistic explanations of H. pylori carcinogenesis at this point in time are hypothetical.
Parity space methods for autonomous fault detection and exclusion using GPS carrier phase

Kinematic carrier phase positioning provides navigation integrity. The sub-centimeter precision of carrier phase measurements can be used to leverage receiver autonomous integrity monitoring (RAIM) in the sense that extremely tight fault detection thresholds can be set on the least-squares residual (ensuring navigation integrity) without incurring high false alarm rates. In addition, the high precision of carrier phase, when compared with code phase, lowers the integrity risk associated with the fault identification process. This is true because carrier phase provides a much cleaner observation of the effect of a given failure on the residual. Thus, for the same improvement in navigation continuity (obtained from fault isolation), misidentification will be less likely. This paper is focused on the use of parity space methods to investigate the limits of high-integrity and high-continuity GPS performance. In this regard, prototype algorithms for receiver autonomous fault detection and exclusion were developed with the goal of maximizing navigation continuity subject to the constraint of maintaining high integrity (by repressing mis-identifications). Fault detection and exclusion performance was demonstrated through analysis and extensive simulation. In addition, the prototype algorithms were implemented in a real-time airborne kinematic positioning architecture and tested by deliberately inducing failures in the post-processing of raw flight data.
Depression following a spinal cord injury

Object:Depression is a common problem following a spinal cord injury (SCI) and can greatly interfere with the rehabilitation process because of reduced energy, negative expectations, and social withdrawal. Understanding various factors which influence a vulnerability to depression may improve the diagnosis and treatment of depressive disorders and can improve rehabilitation outcome.Method:A thorough literature search was conducted using Medline, PsychLit, PyschInfo, and Social Science Citation Index to identify relevant articles published between 1967 and 1995.Results:A diathesis-stress model is proposed to explain the increased risk of depressive symptoms after a SCI. Biological changes associated with SCI and pre-existing cognitive biases may influence the individual's vulnerability to stressful life events following the injury. The nature and frequency of stressful life events following the injury can tax the individual's coping resources. Furthermore, the perceived quality of social support and the se...
Boussinesq and Anelastic Approximations Revisited: Potential Energy Release during Thermobaric Instability

Expressions are derived for the potential energy of a fluid whose density depends on three variables: temperature, pressure, and salinity. The thermal expansion coefficient is a function of depth, and the application is to thermobaric convection in the oceans. Energy conservation, with conversion between kinetic and potential energies during adiabatic, inviscid motion, exists for the Boussinesq and anelastic approximations but not for all approximate systems of equations. In the Boussinesq/anelastic system, which is a linearization of the thermodynamic variables, the expressions for potential energy involve thermodynamic potentials for salinity and potential temperature. Thermobaric instability can occur with warm salty water either above or below cold freshwater. In both cases the fluid may be unstable to large perturbations even though it is stable to small perturbations. The energy per mass of this finite-amplitude instability varies as the square of the layer thickness. With a 4-K temperature difference and a 0.6-psu salinity difference across a layer that is 4000 m thick, the stored potential energy is 0.3 m^2 s^−2, which is comparable to the kinetic energy of the major ocean currents. This potential could be released as kinetic energy in a single large event. Thermobaric effects cause parcels moving adiabatically to follow different neutral trajectories. A cold fresh parcel that is less dense than a warm salty parcel near the surface may be more dense at depth. Examples are given in which two isopycnal trajectories cross at one place and differ in depth by 1000 m or more at another.
Reversal of short photoperiod-induced sterility in male hamsters by ectopic pituitary homografts

In the hamster testicular atrophy can be reversed by ectopic pituitary grafts but effects of this treatment on fertility have not been examined. Adult male hamsters were transferred from a long (14 h of light: 10 h of darkness) to a short photoperiod (5 h of light: 19 h of darkness) to induce atrophy of the testes. Two months later, the animals were given transplants of one or two pituitaries from adult females under the kidney capsule, were sham-operated, or left untreated. After an additional 2 months, all of 7 animals given one graft and 2 of 5 animals given two grafts were fertile while none of 10 control males sired litters. At autopsy, the concentration of testosterone in the plasma and the weights of the testes and the seminal vesicles were significantly higher in grafted than in control animals. Plasma FSH levels were increased only in animals given two transplants, while plasma LH levels were not affected by either of the treatments. Restoration of fertility by pituitary transplants was most likely due to increase in peripheral PRL concentration and in testicular LH receptor levels.
C4d Staining of Pulmonary Allograft Biopsies: An Immunoperoxidase Study

Background The role of antibody-mediated/humoral rejection in lung allografts is not fully elucidated. In other organ systems, deposition of a specific complement product, C4d, is a sensitive and specific marker for humoral rejection. C4d can be evaluated in tissue biopsies by immunofluorescence or light microscopic immunohistochemical staining techniques. Using immunohistochemical staining techniques we sought to determine whether there was any specific staining pattern for C4d in lung allograft biopsies with or without the diagnosis of acute or chronic cellular or humoral rejection. Methods A total of 68 lung transplant biopsies, performed at UCLA Medical Center from January 2002 to August 2004, were collected and the paraffin blocks were re-cut and stained for C4d by an immunoperoxidase technique. The cases were separated by the presence or absence of features of acute and/or chronic rejection based on the International Society for Heart and Lung Transplantation working formulation for the classification of pulmonary allograft rejection, revised 1995. The pattern of staining for C4d was then systematically examined. Results Positive staining in a variable, focal non-specific pattern was observed. There was no consistent staining pattern within the different diagnostic groups. Conclusions C4d staining of paraffin-embedded lung allograft biopsies, using currently available techniques, does not identify acute or chronic cellular or humoral rejection in lung allograft tissue.
Graphical strategies to convey functional relationships in the human brain: a case study

Brain imaging methods used in experimental brain research such as Positron Emission Tomography (PET) and Functional Magnetic Resonance (fMRI) require the analysis of large amounts of data. Exploratory statistical methods can be used to generate new hypotheses and to provide a reliable measure of a given effect. Typically, researchers report their findings by listing those regions which show significant statistical activity in a group of subjects under some experimental condition or task. A number of methods create statistical parametric maps (SPMs) of the brain on a voxelbasis. In our approach statistics are computed not on individual voxels but on predefined anatomical regions-of-interest (ROIs). A correlation coefficient is used to quantify similarity in response for various regions during an experimental setting. Since the functional inter-relationships can become rather complex and spatially widespread, they are best understood in the context of the underlying 3-D brain anatomy. However, despite the power of the 3-D model, the relative location of ROIs in 3-D can be obscured due the inherent problem of presenting 3-D spatial information on a 2-D screen. In order to address this problem, we have explored a number of visualization techniques to aid the brain researcher in exploring the spatial relationships of brain activity. In this paper, we present a novel 3-D interface that allows the interactive exploration of correlation datasets.
Frequency response of resonant converters

The general theory of the discrete small-signal analyses of resonant converters has been formulated in a closed form. For simplicity and verification, the state-plane diagram technique is used for the analysis. This theory is applicable to converters in half-bridge or full-bridge configurations when operated in the continuous conduction mode. Using a series resonant converter (SRC) as an example, the analytic approach based on the state-plane diagram is demonstrated. >
Effect of pH and energy spilling on bacterial protein synthesis by carbohydrate-limited cultures of mixed rumen bacteria.

Abstract Rumen contents were obtained from a cow fed 2.5kg concentrates and 2.5kg timothy hay twice daily, and the mixed rumen bacterial inoculum (pH 6.3) was separated from large feed particles and protozoa by centrifugation. Bacteria were incubated in artificial media at pH 6.7 and 6.0. When starch, sucrose, cellobiose, xylan, pectin, or a mix of carbohydrates were provided to pH 6.7 incubations at 1m M /h for 10h, fermentation was carbohydrate-limited, less than 20% of the carbohydrate was converted to lactate, molar ratio of methane to hexose fermented was as great as 49%, and pH remained constant. When initial pH was lowered to 6.0, methane production was nearly eliminated, volatile fatty acid production was reduced, and there was a small decrease (less than .5) in final pH. At pH 6.0, lactate production was increased in all incubations except xylan and pectin, and pH had a greater effect on acid production than the type of carbohydrate provided. Bacterial protein synthesis was reduced 34 to 69% when initial pH was 6.0, but these reductions were greater than decreases in carbohydrate utilization, increases in lactate, and associated decreases in adenosine 5′-triphosphate production. Because less adenosine 5′-triphosphate was used for protein synthesis, it appeared that low pH diverted energy to nongrowth functions.
Ovarian matrix metalloproteinases are differentially regulated during the estrous cycle but not during short photoperiod induced regression in Siberian hamsters (Phodopus sungorus).

Background Matrix metalloproteinases (MMPs) are implicated as mediators for ovarian remodeling events, and are involved with ovarian recrudescence during seasonal breeding cycles in Siberian hamsters. However, involvement of these proteases as the photoinhibited ovary undergoes atrophy and regression had not been assessed. We hypothesized that 1) MMPs and their tissue inhibitors, the TIMPs would be present and differentially regulated during the normal estrous cycle in Siberian hamsters, and that 2) MMP/TIMP mRNA and protein levels would increase as inhibitory photoperiod induced ovarian degeneration.
A reptation-based model to the dynamics and rheology of linear entangled polymers reinforced with nanoscale rigid particles

Abstract A reptation-based model, that incorporates transient polymer–nanoparticle surface interactions, is proposed to describe the dynamics and rheological behaviors of linear entangled polymers filled with isotropic rigid nanoscale particles. Dispersed nanoparticles are sufficiently small such that even at low volume fractions, the average particle wall-to-wall distance is on the order of the chain size. The model predicts a scaling law in the form, τ d , e f f ∼ τ d ( ϕ a d N + 1 ) 2 , where τd,eff is the effective reptation time of a chain in the presence of attractive nanoparticles, τd is its reptation time in the neat polymer, ϕad is the fraction of attached monomers per chain, and N is the number of monomers per chain. Hence, the overall relaxation is extremely retarded by attractive nanoparticles in the limit of strongly adsorbed chains. Also, it is found that the effective reptation time, τd,eff, can be controlled through five main parameters, i.e., the molecular weight of the polymer chain, N, the size of the nanoparticles, df, the density of attractive site on the nanoparticle surface, nas, the monomer–nanoparticle energetic interaction, ɛ, and the nanoparticle volume fraction, ϕf. The nonequilibrium dynamics of detachment/re-attachment of monomers from/to nanoparticle surfaces under flow conditions is incorporated in the model to elucidate the effect of monomer–surface interactions on the nonlinear viscoelastic behavior. The resulting model correctly captures the linear dynamical properties and shear rheological behaviors of nanocomposite systems studied. Under very slow shear flow conditions, these filled systems exhibit a strong non-Newtonian behavior and a large enhancement in the viscosity as a certain number of monomers in the chain are attached to nanoparticle surfaces, while at very high shear rates, the neat polymer dominates the shear thinning behavior, suggesting that addition of nanoparticles contributes negligible to the viscosity in strong flows. A picture that is based on transient polymer–particle surface interactions, i.e., the detachment/re-attachment dynamics of monomers from/to nanoparticle surfaces is proposed to interpret the observed huge alteration in rheological properties.
Redox properties of electron-transferring flavoprotein from Megasphaera elsdenii

Abstract Electron-transferring flavoprotein (ETF) from the anaerobic bacterium Megasphaera elsdenii catalyzes electron transfer from NADH or d -lactate dehydrogenase to butyryl-CoA dehydrogenase. As a basis for understanding the interactions of ETF with its substrates, we report here on the redox properties of ETF alone. ETF exhibited reversible, two-electron transfer during electrochemical reduction in the presence of mediator dyes. The midpoint redox potentials of the FAD cofactor were −0.185 V at pH 5.5, −0.259 V at pH 7.1 and −0.269±0.013 V at pH 8.4, all versus the standard hydrogen electrode. In the presence of the indicator dye 1-deazariboflavin, the Nernst slopes were 0.029 V and 0.026 V at pH 5.5 and pH 7.1, respectively, compared with an expected value of 0.028 V at 10°C. At pH 8.4, in the presence of 2-hydroxy-1,4-naphthouqinone or phenosafranine, the Nernst slope varied from 0.021 V to 0.041 V. In the experiments at pH 8.4, equilibration was very low slow in the reductive direction and a diffference of as much as 30 mV was observed between reductive and oxidative midpoints. ETF exhibited no thermodynamic stabilization of the radical form of the FAD cofactor during electrochemical reduction at pH 5.5, 7.1 or 8.4. However, up to 93% of kinetically stable, anionic radical was produced by dithionite titration at pH 8.5. Molar absorptivities of ETF radical were 17 000 M −1 · cm −1 at 365 nm and 5100 M −1 · cm −1 at 450 nm. The four ETF preparations used here contained less than 7% 6-OH-FAD. However, two of the preparations contained significant amounts (up to 30%) of flavin which stabilized radical and reduced at potentials 0.2 V more positive than those required for reduction of the major form of ETF. This is referred to as the B form of ETF. The proportion of ETF-FAD in the B form was increased by incubation with free FAD or by a cycle of reduction and reoxidation. These treatments caused marked changes in the absorption spectrum of oxidized ETF and decreases of 20–25% in ETF units/ A 450 .
Comments on «Some evidence against the existence of the liquid-liquid transition. III: The evaluation of the TLL event by differential scanning calorimetry»

The volatile-component evaporation mechanism proposed by Chen et al. to explain molecular-weight-dependent endothermic peaks found at temperatures above Tg in anionically prepared polystyrenes (PSs) on first heating in open DSC pans is inconsistent with several bodies of literature data which were overlooked, including similar data with closed DSC pans. Moreover, this mechanism appears deficient in explaining details of the dependence of the endothermic peak temperature on Mn both below and above the entanglement molecular weight Mc, with a sharp increase in slope at Mc. The original fusion–flow mechanism of Stadnicki et al. is compatible with all other known literature data including results on thermal PS and PMMA fractions. Hot-stage microscope examination of powdered anionic PSs supports the Stadnicki mechanism from Mn = 1900 to at least Mn = 350,000. Addition of small amounts (ca. 1 wt %) of benzene or ethylbenzene to PS results in open-pan DSC traces without endothermic peaks but with an endothermic slope change indicating gradual loss of diluent at decreasing rate as the temperature is increased from below Tg up through the TLL region.
Vitamin K supplementation does not prevent bone loss in ovariectomized Norway rats

Background Despite plausible biological mechanisms, the differential abilities of phylloquinone (PK) and menaquinones (MKn) to prevent bone loss remain controversial. The objective of the current study was to compare the effects of PK, menaquinone-4 (MK-4) and menaquinone-7 (MK-7) on the rate of bone loss in ovariectomized (OVX) Norway rats. A secondary aim was to compare the effects of vitamin K with those of bisphosphonates (BP) on bone loss.
Role of inositol 1,4,5‐triphosphate signalling in gravitropic and phototropic gene expression

Plants sense light and gravity to orient their direction of growth. One common component in the early events of both phototropic and gravitropic signal transduction is activation of phospholipase C (PLC), which leads to an increase in inositol 1,4,5-triphosphate (InsP 3 ) levels. The InsP 3 signal is terminated by hydrolysis of InsP 3 through inositolpolyphosphate-5-phosphatases (InsP 5-ptases). Arabidopsis plants expressing a heterologous InsP 5-ptase have low basal InsP 3 levels and exhibit reduced gravitropic and phototropic bending. Downstream effects of InsP 3 -mediated signalling are not understood. We used comparative transcript profiling to characterize gene expression changes in gravity- or light-stimulated Arabidopsis root apices that were manipulated in their InsP 3 metabolism either through inhibition of PLC activity or expression of InsP 5-ptase. We identified InsP 3 -dependent and InsP 3 -independent co-regulated gene sets in response to gravity or light stimulation. Inhibition of PLC activity in wild-type plants caused similar changes in transcript abundance in response to gravitropic and phototropic stimulation as in the transgenic lines. Therefore, we conclude that changes in gene expression in response to gravitropic and phototropic stimulation are mediated by two signal transduction pathways that vary in their dependence on changes in InsP 3 .
Home Literacy Environment and Its Role in the Achievement of Preschoolers With Disabilities

The purpose of this study was to examine the relationship between the home literacy environment of a nationally representative sample of preschoolers with disabilities and their subsequent receptive vocabulary and reading comprehension skills using data from the Pre-Elementary Education Longitudinal Study. Results from linear regressions indicated that only a small amount of the total variance in children’s receptive language and passage comprehension skills was explained by the home literacy environment. However, the home literacy environment of 3- to 5-year-olds with less severe disabilities was a significant predictor of scores on a test of receptive vocabulary and reading comprehension in later years. The home literacy environment was not a significant predictor of receptive vocabulary or reading comprehension for children with moderate to severe disabilities.
Rethinking Thought Experiments

An examination of two thought experiments in contemporary physics reveals that the same thought experiment can be reanalyzed from the perspective of different and incompatible theories. This fact undermines those accounts of thought experiments that claim their justificatory power comes from their ability to reveal the laws of nature. While thought experiments do play a genuine evaluative role in science, they do so by testing the nonempirical virtues of a theory, such as consistency and explanatory power. I conclude that, while their interpretation presupposes a whole set of background theories and putative laws, thought experiments nonetheless can evolve and be retooled for different theories and ends.
Observing long cosmic strings through gravitational lensing

We consider the gravitational lensing produced by long cosmic strings formed in a grand-unified theory scale phase transition. We derive a formula for the deflection of photons which pass near the strings that reduces to an integral over the light cone projection of the string configuration plus constant terms which are not important for lensing. Our strings are produced by performing numerical simulations of cosmic string networks in flat, Minkowski space ignoring the effects of cosmological expansion. These strings have more small scale structure than those from an expanding universe simulation{emdash}fractal dimension 1.3 for Minkowski versus 1.1 for expanding{emdash}but share the same qualitative features. Lensing simulations show that for both pointlike and extended objects strings produce patterns unlike more traditional lenses, and, in particluar, the kinks in strings tend to generate demagnified images which reside close to the string. Thus lensing acts as a probe of the small scale structure of a string. Estimates of lensing probablity suggest that for string energy densities consistent with string seeded structure formation, on the order of tens of string lenses should be observed in the Sloan Digital Sky Survey (SDSS) quasar catalog. We propose a search strategy in which string lenses would bemore » identified in the SDSS quasar survey, and the string nature of the lens can be confirmed by the observation of nearby high redshift galaxies which are also be lensed by the string. {copyright} {ital 1997} {ital The American Physical Society}« less
Measurement of birefringence of low-loss, high-reflectance coating of m-axis sapphire

The birefringence of a low-loss, high-reflectance coating applied to an 8-cm-diameter sapphire crystal grown in the m-axis direction has been mapped. By monitoring the transmission of a high-finesse Fabry-Perot cavity as a function of the polarization of the input light, we find an upper limit for the magnitude of the birefringence of 2.5 x 10^-4 rad and an upper limit in the variation in direction of the birefringence of 10 deg. These values are sufficiently small to allow consideration of m-axis sapphire as a substrate material for the optics of the advanced detector at the Laser Interferometer Gravitational Wave Observatory.
Solidification and microstructure modelling of welds in aluminium alloys 5754 and 6111

Abstract A solidification and microstructure modelling approach has been developed to predict weld metal and heat affected zone (HAZ) characteristics. The freezing range and phase evolution in the weld metal region were predicted using thermodynamic and diffusion controlled growth calculations. The calculated freezing range was correlated with the weld solidification cracking tendency. A simplified analytical model was suggested to describe thermal cycles that are experienced by the HAZ. This analytical model was coupled with a published microstructure model for age hardenable alloys to predict the hardness variations across the HAZ. The above integrated approach was evaluated using experimental welds made on non­age hardenable 5754 (Al–Mg) and age hardenable 6111 (Al–Mg–Si) alloys using gas tungsten arc, electron beam, and gas metal arc welding processes.
Interference of Barbiturates with Pyrimidine Incorporation: I. Amobarbital Inhibition of Orotate Uptake into Bacillus cereus

Amobarbital, 10-3M, inhibited the conversion of orotate-2-14C into RNA pyrimidines of exponentially growing Bacillus cereus. The drug produced no effect on the growth rate or oxygen uptake of time cells. Furthermore, the incorporation of adenine or uracil into polynucleotides, of amino acids into protein, and of diaminopimelate into cell wall was unaltered by amobarbital. The effect on orotate incorporation was detectable at 10-4 M amobarbital, increased with higher concentrations of the barbiturate, amid decreased as the concentration of orotate in the medium was raised. Studies to localize the effect eliminated the conversion to DNA, the interconversion of RNA pyrimidines, the decarboxylation of orotate, the de novo biosynthesis of pyrimidines, and the flavin-mediated interconversion of orotate and dihydroorotate as the drug-sensitive step. It is concluded that amobarbital, probably as the undissociated compound, markedly depressed the uptake of orotate into the cells. Time otherwise unaffected conversion of this pyrimidine precursor into nucleic acid pyrimidines was therefore limited. This amobarbital-orotate effect had properties of competitive inhibition.
Population Dynamics of Amblyseius fallacies (Acari: Phytoseiidae) and European Red Mite (Acari: Tetranychidae) in Apple Trees Treated with Selected Acaricides

Experiments were conducted to evaluate the effects of early-scason ovicides, selective acaricides, horticultural oil, and potassium salts of fatty acids on the population dynamics of the phytoseiid predator Amblyseius fallacis (Garman) and its prey, the European red mite, Panonychus ulmi (Koch). Both ovicides prevented early-season European red mite outbreaks but only clofentezine-treated trees, with the help of A. fallacis, had low densities of European red mites throughout the entire season. However, treatment with clofentezine kcpt mites at subeconomic levels only if insecticide sprays did not disrupt predator mite populations. Two applications of permethrin drastically reduced natural enemies, and allowed European red mite outbreaks to occur. Selective acaricides varied in their effects on A. fallacies and European red mites. Although not significantly different from each other, all selective acaricides resulted in significantly fewer A. fallacis and European red mites than the untreated trees. Repeated applications of horticultural oils and M-Pede were required to reduce the European red mite populations and were no more effective in conserving predator mites than some of the selective acaricides.
Effect of an antacid on gastrointestinal absorption of theophylline

The effect of a magnesium-aluminum hydroxide antacid (Maalox) on the oral absorption of aminophylline tablets was studied. Twelve healthy adults were administered 200 mg of aminophylline alone or with 30 ml of antacid in a complete crossover study. Blood samples were drawn at 0.33, 0.67, 1, 2, 4, 8, 12, and 24 hours following theophylline (as aminophylline) administration. Theophylline plasma levels were measured by high-performance liquid chromatography. The plasma theophylline concentrations of the group receiving theophylline only were significantly greater than those of the group receiving theophylline plus antacid at the 0.67- and 1-hour sample times only (p less than 0.05). The extent of theophylline absorption and the eliminated rate constant were not significantly affected by the antacid. Antacid significantly decreased theophylline's absorption rate constant (p less than 0.05), indicating a slower absorption of theophylline with antacid. Concurrent administration of the antacid Maalox should not significantly change theophylline's clinical effect.
BLASTING DESIGN AND OPERATION FOR DEMOLITION OF A BRICK-STRUCTURAL BUILDING

In this paper, the design and operation of the demolition blasting of a three storey brick structural building are introduced with inclusion of the size of blasting cuts, the selection of blasting parameters, the design of priming circuit, and safeguard measures.