cssi/SciSciGPT-SciSciNet huggingface dataset:
Growing Cells Push Back under Pressure

In both plants and animals, the interplay between mechanical force generation and mechanical sensing plays a stabilizing role in many developmental processes. Uyttewaal et al. now demonstrate that cells in the Arabidopsis shoot apical meristem respond to local mechanical stresses by reorienting their growth, thereby guiding morphogenesis. Notably, the mechanism underlying such guidance is amplification—not suppression—of growth-rate heterogeneity.
Endogenous expression levels of autoantigens influence success or failure of DNA immunizations to prevent type 1 diabetes: addition of IL-4 increases safety.

Administration of autoantigens through DNA immunizations or via the oral route can prevent progression of islet destruction and lower the incidence of type 1 diabetes in animal models. This beneficial effect is mediated by autoreactive regulatory CD4 lymphocytes, and it is known that their induction depends on the precise dose and route of antigen administration. However, it is not clearwhich endogenous factors determine when such immunizations lead to activation of regulatory versus aggressive autoreactive lymphocytes and how a deleterious outcome can be avoided. Here we describenovel observations made in an animal model for virally induced type 1 diabetes, showing that the endogenous expression levels of the islet antigens and glutamic acid decarboxylase determine whetherimmunization with these antigens is beneficial or detrimental. Lower expression levels in β-cells support immune regulation resulting in induction of autoreactive, regulatory cells characterized by increased IL-4 production (Th2-like), whereas higher levels favor Th1-like autoaggressive responses characterized by augmented IFN-γ generation. Co-immunization with an IL-4-expessing plasmid reduces the risk of augmenting autoaggression and in this way increases the safety margin of this immune-based therapy. Our findings will be of importance for designing safe antigen-specific interventions for human type 1 diabetes.
Influence of subtracheal fat body depletion on thyroid function in the desert iguana.

Abstract 1. 1. Estrogen treatment caused subtracheal fat body depletion with dramatic increases in free fatty acid concentrations in the lizard, Dipsosaurus dorsalis . 2. 2. Thyroid activity increased when free fatty acids were intramuscularly injected into experimental animals. 3. 3. Circulating free fatty acids may competitively inhibit thyroxine binding to serum proteins thereby providing a mechanism for modulation of free thyroxine concentrations in response to variations in physiologic demand. 4. 4. Annual thyroid cycles in certain lizards may reflect the influence of both environmental and metabolic factors.
Differential sensitivity of the insulin receptor to proteolysis after β-adrenergic stimulation

The cellular mechanism by which the specific binding of [125I]insulin to intact rat adipocytes is inhibited by isoproterenol has been studied. By exposing control and isoproterenol-treated cells to trypsin (0-150 micrograms/ml for 20 min at 4 degrees C) and measuring the intact insulin receptor pool following detergent solubilization, a differential sensitivity to proteolysis of the cell membrane receptor was observed. At low trypsin concentration (less than 30 micrograms/ml), approximately 40% of the specific insulin binding in isoproterenol-treated cells was insensitive to proteolysis as compared to control cells. At higher levels of trypsin (50-150 micrograms/ml) both groups displayed similar levels of trypsin-insensitive receptors which, at the highest trypsin concentration, accounted for 10% of the total receptors in intact cells. Detergent-solubilized receptors from isoproterenol-treated cells, on the other hand, exhibited the same sensitivity to trypsin proteolysis as solubilized receptors from control cells. The time course of the onset and reversal of the isoproterenol-induced binding alteration in intact adipocytes has been analyzed by mild trypsinization (20 micrograms/ml). Results indicated that insulin receptors resistant to trypsin under these conditions mediated the decreased surface binding and were re-expressed on the cell surface upon removal of isoproterenol. Experiments in which adipocytes were fractionated into plasma membrane and Golgi-enriched fractions indicated that the loss of surface insulin binding was not accompanied by a decrease in the proportion of receptors in the adipocyte plasma membrane.(ABSTRACT TRUNCATED AT 250 WORDS)
A wolf in sheep's clothing: SV40 co-opts host genome maintenance proteins to replicate viral DNA.

Simian virus 40 (SV40) was discovered in 1960 as a contaminant in early polio vaccines. Its discovery coincided with an explosion of knowledge in the new field of molecular biology, and SV40 was quickly adopted as a model to study eukaryotic genome structure, expression, replication, and cell growth regulation in cultured cells [1]. With a genome of only 5.2 kbp, SV40 relies heavily on host cell machinery to propagate, affording investigators a powerful tool to discover key host proteins that the virus manipulates. Indeed, a single multifunctional viral protein, the large tumor (T) antigen (Tag) (Figure 1A), is sufficient to orchestrate the replication of the viral mini-chromosome in infected monkey cells [2], [3]. The origin DNA binding domain of Tag binds specifically to the viral origin of DNA replication, and the C-terminal helicase domain of Tag unwinds parental DNA at SV40 replication forks. The development of a cell-free reaction containing purified Tag and primate cell extract enabled the identification of ten evolutionarily conserved host proteins that are necessary and sufficient, together with Tag, to replicate SV40 DNA in vitro [3], [4]. Figure 1 Assembly and activation of the SV40 pre-replication complex in vitro.
Non-newtonian secondary flows in ducts of rectangular cross-section

A numerical study of the secondary flows which occur in the laminar pressure-driven motion of dilute polymer solutions in ducts of rectangular cross-section is presented. The full nonlinear equations of motion for a Maxwell fluid with shear thinning are solved by an explicit finite-difference technique. Results are presented in an inertial framing which indicate the existence of the previously observed eight-vortex secondary flow in ducts of various aspect ratios. In addition, the effect of spanwise rotations on the strength and the structure of the secondary flow is examined. The results indicate that even the mere presence of the diurnal rotation of the earth can give rise to a double-vortex secondary flow which is of a comparable order of magnitude to the viscoelastic secondary flows in dilute polymer solutions. Specific computations are presented which illustrate the distortional effect that the imposition of a spanwise rotation has on the viscoelastic secondary flow structure in square ducts. The implications that these results can have on laboratory experiments are discussed briefly along with other possible applications to rotating and curved flows.
A little language for rapidly constructing automated performance tests (abstracts only)

In order to effectively measure the performance of large scale data management solutions at NetApp, we use a fully automated infrastructure to execute end-to-end system performance tests. Both the software and user requirements of this infrastructure are complex: the system under test runs a multi-protocol, highly specialized operating system and the infrastructure serves a diverse audience of developers, analysts, and field engineers (including both sales and support). In this paper we describe our approach to rapidly constructing automated performance system tests by using a lightweight, little, or domain-specific language called SLSL in order to more effectively express test specifications.Using a real world example, we illustrate the efficacy of SLSL in terms of its expressiveness, flexibility, and ease of use by showing a complex test configuration expressed with just a few language constructs. We also demonstrate how SLSL can be used in conjunction with our performance measurement lab to quickly deploy performance tests that yield highly repeatable measurements..
Impact of Thermal Radiation on the Performance of Ultrasmall Microcoolers

On extremely small scales, traditional microcooler performance estimates must be corrected to include losses due to radiation. We present a method for analysis of microcoolers having a significant radiative contribution to their thermal conductance. We have fabricated ultrasmall microcoolers from sputtered Bi2Te3/Sb2Te3 thermoelectric junctions with cooling volumes of 200 μm × 200 μm × 65 nm, which we believe to be the smallest microcoolers ever made. The devices are highly thermally isolated with total thermal conductance under 5 × 10−7 W/K in vacuum at room temperature. By fitting the temperature response to input power of the devices in vacuum, we have quantified the nonlinearity of the response to calculate the radiative and film contributions to the total thermal conductance of the device. Three device geometries are presented, with radiative contributions to thermal conductance of 15%, 26%, and 100% depending on their emissive area and support structure. The cooling capabilities of these devices are also measured with maximum cooling of 3.1 K for the 15% radiation-limited device and 2.6 K for the 26% radiation-limited device, with power consumptions below 5 μW.
Effect of 2-deoxy-D-glucose on gonadotropins, prolactin and serum glucose concentrations in the mare.

Abstract In a variety of species, glucoprivation results in the suppression of the reproductive axis. Two experiments were performed to test the hypothesis that blockade of glucose metabolism via administration of the glucose inhibitor 2-deoxy- d -glucose (2DG) to mares would cause a modification in gonadotropin and prolactin secretion. Long-term ovariectomized mares (Experiment 1, n =4) or ovary-intact mares during the follicular phase of a synchronized estrous cycle (Experiment 2, n =4 per dose) were treated with 2DG. The dose of 2DG used in Experiment 1 was 100 mg 2DG/kg BW, but because severe behavioral responses occurred, lower doses (50, 25, and 12.5 mg 2DG/kg BW) were used for Experiment 2. In addition to the effects of 2DG, the pituitary responsiveness after glucoprivation was determined by an injection of gonadotropin-releasing hormone (100 μg) 6 h post-treatment. In both experiments, treatment with 2DG was unaccompanied by changes in gonadotropin secretion or pituitary responsiveness. Mares treated with 100 mg 2 DG/kg BW exhibited a significant increase in prolactin and mares treated with 100 mg 2DG or 50 mg 2DG/kg BW exhibited a significant increase in serum glucose concentrations, suggesting that glucoprivation was detected at these doses. Lower doses of 2DG did not cause significant alterations in prolactin or glucose levels. These results indicate that 2DG inhibits glucose utilization, but short-term glucoprivation via this metabolic inhibitor does not alter gonadotropin secretion in the mare. This lack of response to glucoprivation may reflect species differences in the response to glucoprivation or may be due to metabolic responses to the inhibition of glucose availability.
Temporal dynamics of particulate matter fluxes and sediment community response in Port Foster, Deception Island, Antarctica

Abstract Time-series particle flux and seasonal sediment community oxygen consumption (SCOC) were measured in Port Foster (160 m water depth), Deception Island, Antarctica, beginning in March 1999 and continuing through November 2000. Sediment traps were moored at 50 and 20 m above bottom and collected sedimenting material for contiguous periods of 10 to 18.3 days. Fluxes of material increased in mid-winter of 1999 and 2000 but were more notable in 1999. Fluxes were higher in the deeper sediment trap and there was an inverse relationship between mass flux and % organic carbon and particulate total nitrogen. A piston-operated grab respirometer was deployed at 160 m depth for 35–60 h in November 1999, and in February, May/June, and November 2000, to measure SCOC and recover the sediment for organic carbon, nitrogen and pigment composition. SCOC, as an estimate of sediment community carbon demand, exceeded the organic carbon flux to the seafloor (supply), and alternative sources of organic carbon input to the benthos are discussed. Highest SCOC occurred in the austral summer during a particle-flux sampling hiatus in the summer of 2000. Fluxes were positively correlated with local wind speed measured at a terrestrial station positioned on a hill overlooking Port Foster. There was also a positive correlation between the particulate matter fluxes and the ratio of chlorophyll a to phaeopigments, an indicator of the “freshness” of material entering the sediment trap at 20 mab.
THE PREPARATION AND CRYSTAL STRUCTURE OF CIS‐ AND TRANS‐POTASSIUM TETRACHLORODINITROPLATINATE(IV)

Abstract The complex cis -K 2 PtCl 4 (NO 2 ) 2 was prepared by reacting K 2 Pt(NO 2 ) 4 with 50% H 2 SO 4 at 100°C and passing the resulting solution through a column of anion-exchange resin in the chloride form. The product that resulted from the initial reaction with sulfuric acid was cis -K 2 Pt(NO 2 ) 2 (SO 4 ) 2 which is an intermediate in the formation of the platinum(III) dimer K 2 [Pt 2 (SO 4 ) 4 (H 2 O) 2 ]. Crystals of cis -K 2 PtCl 4 (NO 2 ) 2 were obtained by evaporation and crystallized in a unit cell with parameters a = 6.438(2) A, b = 7.458(2) A, c = 10.984(2) A, α = 89.66(2)°, β = 99.08(2)°, γ = 92.06(3)°, V = 520 A 3 , Z = 2, space group = P 1 . The previously reported preparation of this cis isomer produced the trans isomer which crystallized in the orthorhombic space group Fddd with unit cell constants a = 15.356(3) A, b = 18.431(4) A, c = 7.361(2) A, V = 2083 A 3 , Z = 8.
Saddle-Shape Annuloplasty Increases Mitral Leaflet Coaptation After Repair for Flail Posterior Leaflet

Background The primary goal of surgical mitral repair is the reestablishment of normal leaflet coaptation. Surgical techniques that maintain or restore leaflet geometry promote leaflet coaptation. Recent 3-dimensional (3D) echocardiographic studies have shown that saddle-shaped annuloplasty has a salutary influence on leaflet geometry. Therefore we hypothesized that saddle-shaped annuloplasty would improve leaflet coaptation in cases of repair for flail posterior leaflet segments. Methods Sixteen patients with flail posterior segment and severe mitral regurgitation had valve repair using standard techniques. Eight patients received saddle-shaped annuloplasty and 8 patients received flat annuloplasty. Real-time 3D transesophageal echocardiography was performed before and after repair. Images were analyzed using custom software to calculate mitral annular area (MAA), septolateral dimension (SLD), intercommissural width (CW), total leaflet area (TLA), and leaflet coaptation area (LCA). Results Postrepair MAA (flat, 588.6 ± 26.5 mm 2 ; saddle, 628.0 ± 35.3 mm 2 ; p = 0.12) and TLA (flat, 2198.5 ± 151.6 mm 2 ; saddle, 2303.9 ± 183.8 mm 2 ; p = 0.67) were similar in both groups. Postrepair LCA was significantly greater in the saddle group than in the flat group (226.8 ± 24.0 mm 2 and 154.0 ± 13.0 mm 2 , respectively; p = 0.02). Conclusions Real-time 3D echocardiography and novel imaging software provide a powerful tool for analyzing mitral leaflet coaptation. When compared with flat annuloplasty, saddle-shaped annuloplasty improves LCA after mitral valve repair for severe mitral regurgitation secondary to flail posterior leaflet segment. Use of saddle-shaped annuloplasty devices may increase repair durability.
Substantial cultures of Propionibacterium can be found in apparently aseptic shoulders revised three years or more after the index arthroplasty

Background Revisions of apparently "aseptic" shoulder arthroplasties are not infrequently culture positive for Propionibacterium , organisms that may be introduced at the time of the index surgery when the dermal sebaceous glands are transected. This report seeks to answer the question, Do surgeons performing revision shoulder arthroplasty years after the index procedure need to be concerned about the persistence of Propionibacterium ? Methods We reviewed the medical records of 148 revision arthroplasties performed between July 2008 and June 2013 to find those revisions performed at least 3 years after the index procedure and at which intraoperative cultures were strongly positive for Propionibacterium . Results We identified 14 cases of revision surgery performed 8 ± 4 years after the original arthroplasty for which deep cultures were strongly positive for Propionibacterium. A total of 109 specimens were obtained, 84 of which were positive. All 14 patients were male. Conclusion Shoulder arthroplasties revised for the mechanical problems of loosening or stiffness can be substantially culture positive for Propionibacterium , even if the revision is performed many years after the index procedure. Therefore, even in shoulder arthroplasties revised for mechanical problems years after the index procedures, surgeons should consider submitting multiple deep specimens for specific Propionibacterium culture. In the presence of persistent Propionibacterium , surgeons should consider the need for directed surgical and medical treatment in their management of a failed arthroplasty.
Myocardial Stunning: An Overview

Over the past two decades, we have challenged the belief that transient ischemia is benign with little functional sequelae following resolution of ischemia. The phenomenon of prolonged postischemic contractile dysfunction, or of myocardial stunning, has been developed and is under investigation using multiple experimental and clinical models. Classifications of myocardial stunning have been suggested and include single and multiple reversible ischemic episodes, partially reversible episodes, and global ischemia. More challenging is the understanding of the mechanisms of myocardial stunning, including free radical protection, excitation-contraction uncoupling, altered calcium flux, microvascular dysfunction, and impaired energy production and use. Finally, advances have been made in the clinical arena, including development of new more sensitive technologies to detect dysfunction, and development of potentially important therapies, including free radical scavengers, adenosine-regulating agents, and calcium channel blockers. In this brief overview, we focus on myocardial stunning, including a historical perspective of coronary occlusion, and definition, classification, and clinical implications of myocardial stunning.
Strategies To Facilitate Organ Donation among African Americans

The greatest challenge for transplantation is the significant disparity in the number of organs available relative to the demand. African Americans in particular are disproportionately represented on the national transplant waiting list for a myriad of reasons. Although accounting for merely 13% of
Flight measurements of tile gap heating on the Space Shuttle

Data are presented from Space Shuttle flight measurements of the temperature distribution within the gaps of the reusable surface insulation tiles. This is the first of a series of flight measurements in which the gap width and tile surface edge radius will be systematically varied. The data show several interesting features including the time and effect of boundary-layer transition. The local heating rates into the gap surfaces are calculated from the measured temperature distribution down the gap at two locations.
Remote sensing of sea state using laser altimeters

The reflection of short laser pulses from the ocean surface is analyzed based on the specular point theory of scattering. The expressions for the averaged received signal, shot noise, and speckle-induced noise are derived for a direct detection receiver system. It is found that the reflected laser pulses have an average shape which is closely related to the probability density function associated with the ocean surface profile. The result is used to estimate the mean sea level and significant wave height from temporal moments of the reflected laser pulse.
The problem of branch-point trajectories in the complex angular momentum plane

It is shown that the interpolating partial wave amplitudeF(s, λ) hasλ-independent branch points in thes-plane corresponding to all physical thresholds, including those involving particles which are members of Eegge trajectories. On the basis of this fact an argument is given which indicates that there are no moving branch points associated with three-particle thresholds, and which makes it plausible that there may also be none connected with higher thresholds. Only those possible branch-point trajectories are considered explicitly which are directly related to two-particle correlations in many-particle states. It is shown briefly that possible moving branch points could not disappear from the physical sheet of the energy plane through two-particle thresholds or through left-hand cuts.
Ruthenium catalyzed synthesis of cross-conjugated polymers and related hyperbranched materials. Copoly(arylene/1,1-vinylene)s

Dihydridocarbonyltris(triphenylphosphine)ruthenium catalyzed copolymerization of acetophenone and 1,4-bis((trimethylsilyl)ethynyl)benzene yields a linear copolymer-copoly[2-acetyl-1,3-phenylene/α,α'-bis((trimethylsilyl)methylene)-1,4-xylenylene]. This reaction involves regioselective catalytic addition of the ortho C-H bonds of acetophenone across the C-C triple bonds of 1,4-bis-((trimethylsilyl)ethynyl)benzene such that the hydrogen becomes bonded to the carbon which bears the trimethylsilyl group. A similar ruthenium catalyzed reaction between 1,4-bis((trimethylsilyl)ethynyl)-benzene and 2-methylacetophenone has been used to prepare a,a'-1,4-bis-[β-(trimethylsilyl)-2-acetyl-3-methylstyrenyl]benzene, a monomeric compound which possesses the same type of chromophore as the linear polymer. Analogous ruthenium catalyzed reaction of 4-((trimethylsilyl)ethynyl)acetophenone yields a hyperbranched material. All three of these cross-conjugated unsaturated materials have regularly alternating arylene and 1,1-vinylene units. These materials have been characterized by 1 H, 13 C, and 29 Si NMR and by IR, UV, and fluorescence spectroscopy. Polymer properties have been measured by GPC, DSC, and TGA.
Rehydration Capacities and Rates for Various Porcine Tissues after Dehydration

The biphasic effects of liquid on tissue biomechanics are well known in cartilage and vocal folds, yet not extensively in other tissue types. Past studies have shown that tissue dehydration significantly impacts biomechanical properties and that rehydration can restore these properties in certain tissue types. However, these studies failed to consider how temporal exposure to dehydrating or rehydrating agents may alter tissue rehydration capacity, as overexposure to dehydration may permanently prevent rehydration to the initial liquid volume. Select porcine tissues were dehydrated until they reached between 100% and 40% of their initial mass. Each sample was allowed to rehydrate for 5 hours in a 0.9% saline solution, and the percent change between the initial and rehydrated mass values was calculated. Spearman correlation tests indicated a greater loss in mass despite rehydration when tissues were previously exposed to greater levels of dehydration. Additionally, Pearson correlation tests indicated the total liquid mass of samples after complete rehydration decreased when previously exposed to higher levels of dehydration. Rehydration rates were found by dehydrating tissues to 40% of their initial mass followed by rehydration in a 0.9% saline solution for 60 minutes, with mass measurements occurring in 15 minute intervals. All tissues rehydrated nonlinearly, most increasing significantly in mass up to 30 minutes after initial soaking. This study suggests the ability for tissues to rehydrate is dependent on the level of initial dehydration exposure. In vitro rehydration experiments therefore require controlled dosage and temporal exposure to dehydrating and rehydrating agents to avoid incomplete rehydration, and caution should be taken when combining different tissue types in models of hydration.
Normal photoelectron diffraction of c(2 x 2)O(1s)-Ni(001) and c(2 x 2)S(2p)-Ni(001),with Fourier-transform analysis

Normal photoelectron diffraction was used to study the structure of the $c(2\ifmmode\times\else\texttimes\fi{}2)\mathrm{O}$ and $c(2\ifmmode\times\else\texttimes\fi{}2)\mathrm{S}$ overlayers on Ni(001). The oxygen and sulfur atoms were found to lie above the fourfold hollow sites in the Ni(001) surface with ${d}_{1}$ spacings of 0.90\ifmmode\pm\else\textpm\fi{}0.04 and 1.30\ifmmode\pm\else\textpm\fi{}0.04 \AA{}, respectively, where ${d}_{1}$ is the perpendicular interplanar spacing between the adsorbate and surface layers. A Fourier-transform analysis was carried out on the experimental data. In both cases, the modulus of the Fourier transforms gave two large peaks in the real-space distribution function. The maxima of these peaks closely corresponded to ${d}_{1}+b$ and ${d}_{1}+2b$, where $b$ is the interlayer spacing in Ni(001). The range of experimental data in $k$ space was not large enough to yield the value of ${d}_{1}$ directly.
Characterizing fluorine and chlorine atom flow rates using iodine atom spectrometry

The production of F and Cl atoms in an electrical discharge of F 2 or Cl 2 has been examined in a flow reactor. A tunable diode laser was used to probe the concentration and translational temperature of I atoms produced by F and Cl atom reactions with HI. Kinetic modeling codes were used to determine the discharge efficiencies from the titration plots and the observed trends for atom concentration as a function of F 2 or Cl 2 and pressure. These calculations indicate that the de discharge used in these experiments is 100% efficient for F 2 flow rates ≤0.5 mmol s -1 and reactor pressure ≤20 torr. The highest F 2 -free F atom flow rate that we can generate is 1.0 mmol s -1 . Preliminary data for the Cl 2 discharge indicate that this is a much less efficient source of Cl atoms with yields of less than 50%.
An appraisal of RECQ1 expression in cancer progression

RECQ1 is the most abundant member of the human RecQ family of DNA helicases genetically linked with cancer predisposition syndromes and well known for their functions in genome stability maintenance through DNA repair. Despite being the first discovered RecQ homolog in humans, biological functions of RECQ1 have remained largely underappreciated and its relevance to cellular transformation is yet unclear. RECQ1 is overexpressed and amplified in many clinical cancer samples. In silico evaluation of RECQ1 mRNA expression across the NCI-60 cancer cell lines predicts an association of RECQ1 with cancer cell migration, invasion, and metastasis. Consistent with this, latest work implicates RECQ1 in regulation of gene expression, especially of those associated with cancer progression. Functionally, silencing RECQ1 expression significantly reduces cell proliferation, migration, and invasion. Collectively, these results propose that discerning the role of RECQ1 in conferring proliferative and invasive phenotype to cancer cells could be useful in developing therapeutic strategies to block primary tumor progression and metastasis.
Pharmacokinetics and Bioavailability of the Flavonoid 7,8-Benzoflavone in Rats

The flavonoid 7,8-benzoflavone was recently identified as one of the most potent inhibitors of breast cancer resistance protein (BCRP); however, little is known of the in vivo disposition of 7,8-benzoflavone. The objective of this study was to investigate the pharmacokinetics and bioavailability of 7,8-benzoflavone in rats. Three intravenous (5, 10, and 25 mg/kg) and three oral (12.5, 25, and 50 mg/kg) doses were administered to female Sprague-Dawley rats. Plasma samples were analyzed by high-performance liquid chromatography. Pharmacokinetic analysis was conducted by WinNonlin and ADAPT II. The dose-normalized plasma concentration versus time curves did not superimpose with each other, indicating the nonlinear pharmacokinetics of 7,8-benzoflavone. 7,8-benzoflavone exhibited a large volume of distribution (V(ss) approximately 1.5 L/kg) and rapid oral absorption (t(max) < 30 min). The bioavailability of 7,8-benzoflavone was low (0.61-13.2%) and dose-dependent. A pharmacokinetic model with dose-dependent bioavailability, linear absorption and nonlinear elimination best described the pharmacokinetic profiles of 7,8-benzoflavone. Using a 50 mg/kg oral dose of 7,8-benzoflavone, we could significantly increase the AUC for the BCRP substrate nitrofurantoin, demonstrating the potential for BCRP-mediated drug interactions.
The effect of reversible lesions in the posterior hypothalamus on conditioned suppression

Three rats with cannulae implanted in the posterior hypothalamic area and one nonimplant rat were tested in a conditioned suppression paradigm. During the acquisition phase of conditioned suppression, xylocaine hydrochloride was administered bilaterally via cannulae to two of the implant animals and an equal volume of normal saline was administered to the third animal. The xylocaine-injected animals required approximately twice the number of CS-UCS pairings as the saline-injected animal and five times the number of CS-UCS pairings as the normal control animal to acquire conditioned suppression. The maintenance of conditioned suppression was generally unaffected by xylocaine lesions.
The bacterial ribonuclease P holoenzyme requires specific, conserved residues for efficient catalysis and substrate positioning

RNase P is an RNA-based enzyme primarily responsible for 5′-end pre-tRNA processing. A structure of the bacterial RNase P holoenzyme in complex with tRNAPhe revealed the structural basis for substrate recognition, identified the active site location, and showed how the protein component increases functionality. The active site includes at least two metal ions, a universal uridine (U52), and P RNA backbone moieties, but it is unclear whether an adjacent, bacterially conserved protein loop (residues 52–57) participates in catalysis. Here, mutagenesis combined with single-turnover reaction kinetics demonstrate that point mutations in this loop have either no or modest effects on catalytic efficiency. Similarly, amino acid changes in the ‘RNR’ region, which represent the most conserved region of bacterial RNase P proteins, exhibit negligible changes in catalytic efficiency. However, U52 and two bacterially conserved protein residues (F17 and R89) are essential for efficient Thermotoga maritima RNase P activity. The U52 nucleotide binds a metal ion at the active site, whereas F17 and R89 are positioned >20 A from the cleavage site, probably making contacts with N−4 and N−5 nucleotides of the pre-tRNA 5′-leader. This suggests a synergistic coupling between transition state formation and substrate positioning via interactions with the leader.
Plate Fin Regenerators for Industrial Gas Turbines

This paper reviews Harrison Radiator’s various designs and improvements in the Industrial Gas Turbine Regenerator that it has been supplying over the past 20 years, and describes a new design regenerator intended for high cyclic and/or high temperature operation. Design improvements and surface changes have occurred to keep pace with the changing consumer’s requirements and application. These changes have been effective in improving the cyclic ability of the regenerator and in reducing the field maintenance required on the earlier models due to the changing mode of operation. The new regenerator design has been created to meet the changing requirements of the applications.
The dynamics of cytosolic calcium in photoreceptor cells.

Analysis of the light-induced changes of cytosolic Ca2+ ([Ca2+]i) in photoreceptor cells has been taken a step further with two recently published studies(1,2). In one, changes in [Ca2+]i were measured in single detached rod outer segments from Gecko in response to various light intensities. The advances of the other(2) are embodied in its employment of transgenic Drosophila, whose photoreceptors express a visual pigment that is insensitive to the wavelength of light used in the fluorescence imaging of [Ca2+]i. These studies provide a better basis for understanding the regulation of Ca2+-mediated events in photoreceptor cells.
Crystallization and preliminary structural studies of a chorismate mutase catalytic antibody complexed with a transition state analog.

The Fab′ fragment of a catalytic antibody with chorismate mutase activity has been crystallized as a complex with the transition-state analog hapten. The complex was crystallized by the vapor diffusion method using ammonium sulfate as the precipitant. The crystals belong to the orthorhombic space group P212121 with unit cell dimensions a = 37.1 A, b = 63.3 A, c = 178.5 A, and there is one Fab' molecule per asymmetric unit. The crystals diffract X-rays to at least 3.0 A and are suitable for X-ray crystallographic studies. © 1994 John Wiley & Sons, Inc.
Kinetics of phosphoglucose ester hydrolysis by rat intestinal mucosa.

SummaryThe enzymatic hydrolysis of glucose 1-phosphate (G1P) and glucose 6-phosphate (G6P) by homogenates of rat intestinal mucosa was quantitated. These substrates were not utilized by enzymes other than phosphatases to any appreciable extent. The mean Km value for the hydrolysis of G6P was higher (4.3 mM) than that for G1P (1.69 mM). A variability was observed in Km values in each substrate group. However, the Km/Vmax ratio was constant for each of the two substrates. Such proportional changes in Km and Vmax values allow the approximation of the rate constant (K1) related to the formation of the enzyme-substrate complex. The K1 value thus estimated for G1P was approximately 1.68 times that for G6P.This work was supported by U. S. Army Research and Development Command, Department of the Army, under Research Contract No. DA-49-193-MD-2415, and by Research Grant AM 11945 from the National Institutes of Health, U. S. Public Health Service.
Attribution of Projected Changes in Atmospheric Moisture Transport in the Arctic: A Self-Organizing Map Perspective

Abstract Meridonal moisture transport into the Arctic derived from one simulation of the National Center for Atmospheric Research Community Climate System Model (CCSM3), spanning the periods of 1960–99, 2010–30, and 2070–89, is analyzed. The twenty-first-century simulation incorporates the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emission Scenarios (SRES) A2 scenario for CO2 and sulfate emissions. Modeled and observed [from the 40-yr ECMWF Re-Analysis (ERA-40)] sea level pressure (SLP) fields are classified using a neural network technique called self-organizing maps to distill a set of characteristic atmospheric circulation patterns over the region north of 60°N. Model performance is validated for the twentieth century by comparing the frequencies of occurrence of particular circulation regimes in the model to those from the ERA-40. The model successfully captures dominant SLP patterns, but differs from observations in the frequency with which certain patterns occur. The model’s...
Six Key Principles for Music Assessment.

valuating students' performance and measuring growth are ongoing foundational activities in the educational process. This article evolved from conversations between the authors about essential information that preservice teachers need to be able to assess their students fairly and effectively. Although our expertise is in different fields-educational psychology and music education-we both have experience working with future music educators. In our discussions, critical themes emerged that are basic for evaluating musical skills and knowledge. Using our experience and current research, we created six principles for developing effective measurement tools. These principles can remind experienced teachers and provide guidance for novice educators about core issues in music assessment.
Sociopsychological factors affecting the human response to noise exposure

Community noise is reported to be the most often mentioned undesirable neighborhood condition in a recent U.S. Census survey. Understanding community response to noise involves the measurement of a number of complex acoustic and nonacoustic variables and establishing the chain of relationships between physical exposure, perception, annoyance, and acceptability responses and finally complaint behavior. The perceived loudness of a noise is the most important acoustic parameter influencing annoyance and complaints, and the simple dBA unit can be used to integrate spectral characteristics of complex sounds in community studies. Although energy averaging such as Leq or Ldn can be used to describe multiple noise exposures over time, the variable trade-off relationships between number and level of exposures are somewhat obscured by such summary measures. However, they are still the best available descriptors and, until more accurate ones are developed, can be used to measure community noise environments. Perception of an identical noise exposure can vary according to the physiological noise sensitivity of a person and the activity context in which the noise is heard. Although the acoustic quality of the noise itself usually explains about 10 to 25 per cent of the variability in annoyance responses, sociopsychological variables measured in field studies account for 35 to 50 per cent of the variations in human annoyance responses. Three of the most important nonacoustic factors are the connotative fear effects of the noise signal, the feeling that those responsible for the noise are misfeasant in not reducing the noise, and the feeling that harmful health effects are produced by the noise. When residents report great fear, a high misfeasance, and marked health effects, about 90 per cent report a high annoyance level whether their noise exposure level is above 90 Ldn or 65 to 70 Ldn. In contrast, if the feelings are a low fear level, a low degree of misfeasance, and minimal health effects, only 3 to 10 per cent give high annoyance responses. Complaint behavior, although based on intensity of annoyance, is modified by a number of other sociopsychological factors and often is an unreliable indicator of an environmental problem.
The dielectric strength of glass-an engineering viewpoint

The purpose of this paper is to provide the engineer with co-ordinated information and data regarding the dielectric breakdown of glass which will permit him to apply this insulating material more effectively for high dielectric strength. In the discussion of the subject, particular attention has been paid to “edge effects” and other factors which cause wide variations in breakdown voltages — variations which are responsible for many of the seeming inconsistencies found in published results on the dielectric failure of glass and other materials. The author has concluded that it is possible to make a reasonable approximation of the breakdown voltage of glass, if the conditions of the test or of the application can be sufficiently well determined. The characteristic breakdown curves of this paper do not represent the results of any one series of tests, but are rationalized from data selected from many sources, including unpublished tests. The data curves included refer mainly to Pyrex∗ glass, but corresponding data have also been included on electrical porcelain because of the interesting comparisons shown.
Talk about change

Purpose – The purpose of this paper is to discuss the importance of having conversations with staff regarding organizational change and financial futures. Design/methodology/approach – This article refers to several relevant works already published. Findings – The book and articles discussed provide guidelines for preparing for and having staff discussions. Originality/value – This point of view is based on the author's experiences and actions on related matters.
Hybrid Fourier finite difference 3D depth migration for anisotropic media

When a subsurface is anisotropic, migration based on the assumption of isotropy will not produce accurate migration images. We develop a hybrid wave-equation migration algorithm for vertical transversely isotropic (VTI) media based on a one-way acoustic wave equation, using a combination of Fourier finite-difference (FFD) and finite-difference (FD) approaches. The hybrid method can suppress an additional solution that exists in the VTI acoustic wave equation, and it offers speed and other advantages over conventional FFD or FD methods alone. The algorithm is tested on a synthetic model involving log data from onshore eastern Saudi Arabia, including estimates of both intrinsic and layer-induced VTI parameters. Results indicate that VTI imaging in this region offers some improvement over isotropic imaging, primarily with respect to subtle structure and stratigraphy and to image continuity. These benefits probably will be overshadowed by perennial land seismic data issues such as near-surface distortions and multiples.
Comparison of Subtyping Methods for Differentiating Salmonella enterica Serovar Typhimurium Isolates Obtained from Food Animal Sources

Molecular characterization (e.g., DNA-based typing methods) of Salmonella isolates is frequently employed to compare and distinguish clinical isolates recovered from animals and from patients with food-borne disease and nosocomial infections. In this study, we compared the abilities of different phenotyping and genotyping methods to distinguish isolates of Salmonella enterica serovar Typhimurium from different food animal sources. One hundred twenty-eight S. enterica serovar Typhimurium strains isolated from cattle, pigs, chickens, and turkeys or derived food products were characterized using pulsed-field gel electrophoresis (PFGE), repetitive element PCR (Rep-PCR), multilocus sequence typing (MLST), plasmid profiling, and antimicrobial susceptibility testing. Among the 128 Salmonella isolates tested, we observed 84 Rep-PCR profiles, 86 PFGE patterns, 89 MLST patterns, 36 plasmid profiles, and 38 susceptibility profiles. The molecular typing methods, i.e., PFGE, MLST, and Rep-PCR, demonstrated the best discriminatory power among Salmonella isolates. However, no apparent correlation was evident between the results of one molecular typing method and those of the others, suggesting that a combination of multiple methods is needed to differentiate S. enterica serovar Typhimurium isolates that genetically cluster according to one particular typing method.
Targeting Radioresistant Osteosarcoma Cells With Parthenolide

Osteosarcoma is a devastating tumor of bone, primarily affecting adolescents. Osteosarcoma tumors are notoriously radioresistant. Radioresistant cancers, including osteosarcoma, typically exhibit a considerable potential for relapse and development of metastases following treatment. Relapse and metastatic potential can, in part, be due to a specific radioresistant subpopulation of cells with stem-like characteristics, cancer stem cells, which maintain the capacity to regenerate entire tumors. In the current study, we have investigated whether in vitro treatments with parthenolide, a naturally occurring small molecule that interferes with NF-κB signaling and has various other effects, will re-sensitize cancer stem cells and the entire cell population to radiotherapy in osteosarcoma. Our results indicate that parthenolide and ionizing radiation synergistically induce cell death in LM7 osteosarcoma cells. Importantly, the combination treatment results in a significant reduction in the viability of both the overall population of osteosarcoma cells and the cancer stem cell subpopulation. This effect is dependent on the ability of parthenolide to induce oxidative stress. Therefore, as a supplement to current multimodal therapy, parthenolide may sensitize osteosarcoma tumors to radiation and greatly reduce the prevalence of relapse and metastatic progression.
Comparative evaluation of immunization with live attenuated and inactivated poliovirus vaccines

The development of serum and nasopharyngeal antibody response, as well as the magnitude and temporal pattern of fecal shedding of vaccine and revertant polio-viruses, have been examined in infants previously immunized with one or more doses of orally administered live attenuated poliovaccine, enhanced potency inactivated polio-vaccine, or both. The nature of serum immune response appears to be similar after either immunization schedule, although the antibody titers are quantitatively higher after two doses of EP-IPV than those observed after a similar schedule with OPV. Highest antibody activity is generally detected in subjects immunized with a combination of EP-IPV followed by OPV. ELISA antibody activity in the nasopharynx was regularly detected after either form of immunization. However, neutralizing and VP3 poliovirus virion protein-specific antibody responses in the nasopharynx were consistently observed in subjects immunized with OPV or EP-IPV followed by OPV. Subjects immunized with EP-IPV alone exhibit significantly lower or absent neutralizing or VP3-specific responses. The nucleic acid sequences of the purified RNA obtained from all virus isolates have also been examined in the 5' noncoding region by dideoxy-sequencing to determine whether the viruses shed represent revertants (vaccine), non-revertants, or both. The frequency and duration of vaccine virus shedding appears to be similar in both immunization schedules. Revertant virus shedding was not demonstrated 30 days after immunization with OPV alone. However, shedding of revertants was detected for as long as 60 days in some subjects previously immunized with EP-IPV. The duration of shedding of revertant virus differed with different serotypes and different immunization regimens. Prior immunization with one or more doses of OPV reduced the length of shedding of revertant virus. Significantly, however, prior immunization with one or more doses of EP-IPV was not associated with reduced shedding of revertant virus types. Based on these observations and a number of other epidemiologic data summarized in this review, it is clear that both OPV and EP-IPV when used alone are highly effective and safe in inducing effective immunity to polio-virus and in the eradication of poliomyelitis. While the combination schedule employing EP-IPV followed by OPV should result in a decline of vaccine-associated paralytic (VAP) disease in OPV recipients, such immunization schedules may have little or no impact on the development of VAP in susceptible contacts. Furthermore, the logistics and the cost of combination schedules must be considered before current recommendations based on the use of OPV or EP-IPV alone are revised.
Microenvironment analysis and identification of magnesium binding sites in RNA

Interactions with magnesium (Mg2+) ions are essential for RNA folding and function. The locations and function of bound Mg2+ ions are difficult to characterize both experimentally and computationally. In particular, the P456 domain of the Tetrahymena thermophila group I intron, and a 58 nt 23s rRNA from Escherichia coli have been important systems for studying the role of Mg2+ binding in RNA, but characteristics of all the binding sites remain unclear. We therefore investigated the Mg2+ binding capabilities of these RNA systems using a computational approach to identify and further characterize their Mg2+ binding sites. The approach is based on the FEATURE algorithm, reported previously for microenvironment analysis of protein functional sites. We have determined novel physicochemical descriptions of site-bound and diffusely bound Mg2+ ions in RNA that are useful for prediction. Electrostatic calculations using the Non-Linear Poisson Boltzmann (NLPB) equation provided further evidence for the locations of site-bound ions. We confirmed the locations of experimentally determined sites and further differentiated between classes of ion binding. We also identified potentially important, high scoring sites in the group I intron that are not currently annotated as Mg2+ binding sites. We note their potential function and believe they deserve experimental follow-up.