cssi/SciSciGPT-SciSciNet huggingface dataset:
Reduction of manganese(III) protoporphyrin IX dimethyl ester studied by electrochemistry and surface-enhanced Raman scattering spectroscopy

The reductive electrochemistry of manganese(III) protoporphyrin IX dimethyl ester, Mn III (PPDME), in an aprotic solvent was studied using cyclic voltammetry, surface-enhanced Raman scattering spectroscopy (SERS), and thin layer potential dependent UV/vis absorption spectroscopy. Good quality SERS spectra are reported for an electrochemically roughened silver electrode in contact with Mn(PPDME) dissolved in acetonitrile. A reversible one-electron reduction was observed at ca. -0.44 V/SCE in the cyclic voltammetric scans on silver, gold, and platinum electrodes. In thin layer UV/vis spectroelectrochemistry, the Soret band at 473 nm at 0.0 V undergoes a 36 nm blue shift to 437 nm when the electrode potential was stepped to -0.5 V. Resonance Raman and SERS spectral frequencies of Mn(PPDME) are assigned and tabulated. The shift of the Soret band along with the downshift in the ν 4 oxidation state marker band from 1373 to 1360 cm -1 in the SERS spectra identify the process occurring at ca. -0.5 V to be the reduction of the porphyrin central metal ion from the Mn III to Mn state. Core sizes for Mn III (PPDME) and Mn II (PPDME) adsorbed on an anodized silver electrode surface were calculated to be 1.993 and 2.072 A, respectively. Both the Mn II and Mn III complexes are adsorbed as high spin, five-coordinate species. On the basis of relative intensities of the SERS bands, the orientation of Mn(PPDME) adsorbed onto the silver electrode surface is proposed to be face-on.
Discharge patterns of chicken cochlear ganglion neurons following kanamycin-induced hair cell loss and regeneration

Hair cells in the basal, high frequency region (>1100 Hz) of the chicken cochlea were destroyed with kanamycin (400 mg/kg/d × 10 d) and allowed to regenerate. Afterwards, single unit recordings were made from cochlear ganglion neurons at various times post-treatment. During the first few weeks post-treatment, only neurons with low characteristic frequencies (<1100 Hz) responded to sound. Despite the fact that the low frequency region of the cochlea was not destroyed, neurons with low characteristic frequencies had elevated thresholds, abnormally broad U-shaped or W-shaped tuning curves and low spontaneous discharge rates. At 2 days post-treatment, the spontaneous discharge rates of some acoustically unresponsive units fluctuated in a rhythmical manner. As recovery time increased, thresholds decreased, tuning curves narrowed and developed a symmetrical V-shape, spontaneous rate increased and neurons with higher characteristic frequencies began to respond to sound. In addition, the proportion of interspike interval histograms with regularly spaced peaks increased. These improvements progressed along a low-to-high characteristic frequency gradient. By 10–20 weeks post-treatment, the thresholds and tuning curves of neurons with characteristic frequencies below 2000 Hz were within normal limits; however, the spontaneous discharge rates of the neurons were still significantly lower than those from normal animals.
Republican campaign rhetoric: Reflections of a meaner, tougher America

This article examines some Republican communication behaviors that account, in part, for accusations that the use of negative strategies was unprecedented during the 1988 presidential campaign. It also explores some of the effects of those strategies on political communication behavior during the first year of the Bush administration. It is suggested that a kind of systemic demagoguery may have produced Campaign ‘88 and its legacy. Parts of that system include the process, the polls, the packagers, the press, and the public. The paper concludes with some suggestions for modifying the campaign system to discourage demagogic communication.
Scaling of the surface tension of phase-separated polymer solutions

The tension of the interface between the equilibrium phases of a phase-separated polymer solution is obtained in the simplest mean-field approximation from the functional equation for the composition profile of the interface. For temperatures T near the critical solution temperature T/sub c/, i.e., for Flory parameter X near X/sub c/, and for high degrees of polymerization N, the profile and tension scale with x = N/sup 1/2/(X-X/sub c/), just as do the compositions of the coexisting phases in mean-field approximation. The surface tension sigma in the asymptotic limit N ..-->.. infinity, X ..-->.. X/sub c/ at fixed x, is found to be given by a/sup 2/sigma/kT/sub c/ approx. (2c'/c)/sup 1/2/N/sup -5/4/ ..sigma.. (x), where a is the lattice spacing of an underlying lattice (or, roughly, the length of a monomer), c' and c are the vertical and total coordination numbers of the lattice, and ..sigma..(x) is a scaling function, known for all x, with the asymptotic behavior ..sigma..(x) approx. 4 root 2 x/sup 3/2/ as x ..-->.. 0 and ..sigma..(x) approx. (6 root 2/5) x/sup 5/2/ as x ..-->.. infinity. The latter implies that sigma becomes independent of N as N ..-->.. infinity at fixed T near T/sub c/; themore » former implies that sigma becomes proportional to N/sup -1/2/(1 - T/T/sub c/)/sup 3/2/ as T ..-->.. T/sub c/ at fixed N >> 1, as found previously.« less
Electrical inexcitability of the synaptic membrane in the frog skeletal muscle fibre.

VARIOUS types of evidence indicate that the end-plate potential of frog twitch muscle fibres is an electrically inexcitable synaptic activity1,2. Electrical inexcitability of the synaptic membrane has been demonstrated most clearly in cells in which electrically excitable activity is lacking, for example, the electro-plaques of marine electric fishes3 and slow muscle fibres of frog4. Electrical inexcitability of synaptic membranes in other cells has also been demonstrated1,2. Hitherto, however, it has not been shown that the chemically excitable5 synaptic membrane of twitch muscle fibres is also unresponsive to electrical stimuli. The junctional region is small, and there is intermingling of membrane of greater and lesser chemical sensitivity5.
Mechanical and electrical effects of high-frequency and high-intensity stimulation of muscle.

A unique tension response can be obtained by stimulating an isometrically held skeletal muscle or a single muscle fiber by a train of high-frequency pulses (2,000 pps) at higher-than-normal intensity, or by a long DC pulse. It is called the tetanoid response, and it is composed of three well-defined stages. Initially, tension develops rapidly, and mechanical output (P0) reaches about 0.35. Subsequently, this tension is maintained at a nearly steady level for the remainder of stimulation. After stimulation, a final increase of tension takes place. Intracellular electrical recordings show that the initial development of tension is elicited by two or three action potentials generated at the beginning of the stimulation, and that no additional action potentials are generated for the remainder of stimulation. During stimulation, part of the fiber membrane (regarded in cross-section) is depolarized, which generates tension, and part of the membrane is hyperpolarized. With termination of stimulation, a single action potential is elicited via anode-break excitation (ABE) on the hyperpolarized portion of the membrane, which gives rise to the final increase of tension.
Assessment of the Resistance to Uranium (VI) Exposure by Arthrobacter sp. Isolated from Hanford Site Soil

Production of nuclear fuel has resulted in hazardous waste streams that have contaminated the soil and groundwater. Arthrobacter strains, G975, G968, and G954 were used in the prescreening tests to evaluate their tolerance to UO2 2+ and investigate bacteria-U(VI) interactions under oxidizing pH-neutral conditions. Experiments have shown G975 is the fastest growing and the most uranium tolerant strain that removed about 90% of uranium from growth media. Atomic Force Microscopy images exhibited an irregular surface structure, which perhaps provided a larger surface area for uranium precipitation. The data indicate that aerobic heterotrophic bacteria may offer a solution to sequestering uranium in oxic conditions, which prevail in the vadose zone.
A simple method for immunoaffinity purification of nondenatured avian sarcoma and leukemia virus gag-containing proteins

We have developed a one-step purification procedure for proteins containing the N-terminal portion of the gag protein of avian sarcoma and leukemia viruses. In this procedure, a resin with a covalently attached monoclonal antibody to the gag protein p19 is used to bind gag-containing proteins from crude extracts. After washing of the resin, the bound proteins are eluted with 2 M MgCl2. For the transforming protein kinase encoded by Fujinami sarcoma virus p130gag-fps, this procedure gave an enrichment of several thousand-fold, a yield of over 10%, a final purity of over 20%, and no significant loss of protein kinase activity. Similar purifications were obtained with three other gag-containing proteins. The immunoaffinity purification described may be of general utility as a first step in purification of the several other avian retroviral transforming proteins that are synthesized from fusions of an oncogene with the viral gag gene.
Human Parathyroid Hormone (PTH)-Related Protein and Human PTH: Comparative Biological Activities on Human Bone Cells and Bone Resorption

Human PTH-related protein (hPTHrP) has been characterized as a product of tumor cells with sequence homology to the biologically active amino-terminal portion of human PTH (hPTH). We measured the relative activities of synthetic amino-terminal sequences of hPTH-(1-34) and hPTHrP-(1-34) to stimulate production of cAMP in intact human SaOS-2 osteosarcoma cells. Both peptides enhanced cAMP production at concentrations of 2.5-7.5 X 10(-10) M, had parallel dose-response curves, and were of essentially equal potency. Preincubation of SaOS-2 cells with hPTH-(1-34) or hPTHrP-(1-34) for 1 or 4 h induced homologous desensitization to a second challenge with the same peptide as well as heterologous desensitization to the other PTH peptide, but had little or no effect on the action of vasoactive intestinal peptide; the magnitudes of homologous and heterologous desensitization induced by the same doses of hPTHrP-(1-34) or hPTH-(1-34) were similar. Bone resorption-stimulating activity was measured using 40Ca2+ release from neonatal mouse calvariae in organ culture after 72 h of incubation. hPTHrP-(1-34) gave a dose-response between 0.2 and 5 ng/ml (5 X 10(-11) and 1.2 X 10(-9) M), was about 3 times more potent than Lilly bovine PTH standard (assuming a SA of 3000 U/mg; 100 U/ml), gave the same maximum response as hPTH-(1-34), and was 20-30% as potent as hPTH-(1-34). Neither hPTH-(1-34) nor hPTHrP-(1-34) enhanced prostaglandin production in mouse calvariae, and indomethacin did not inhibit the bone resorption-stimulating activities of either peptide. We conclude that hPTHrP-(1-34) and hPTH-(1-34) have similar high specific biological activities to stimulate production of cAMP in human osteoblast-like cells, but that hPTHrP-(1-34) is modestly less potent than hPTH-(1-34) to stimulate bone resorption in mouse calvariae.
Fluoride inhibition of sodium extrusion from swine erythrocytes and its metabolic correlates

Abstract Fluoride, like iodoacetamide, inhibits active sodium extrusion from swine erythrocytes. The latter acts by inhibiting metabolism of adenosine (provided as a substrate) with the result that cellular ATP disappears within 2 hours. However, fluoridetreated cells contain 85% as much ATP as control cells, and P 32 incorporation into ATP is only slightly depressed. Lactic acid production is decreased by fluoride only during the early part of an experiment. Fluoride, in concentrations capable of blocking ion transport, inhibits an ATPase known to be required for this process. The data suggest that inhibition of sodium extrusion is the result of failure of this enzyme, not because ATP synthesis stops. Human erythrocytes provided with adenosine also have near normal ATP levels. Lactic production is decreased only moderately by fluoride in concentrations known to block glycolysis completely.
Restating the Case: The Benefits of Diverse Samples for Theory Development

Although I ultimately agree with Henry's (this issue) call for prejudice researchers to study more diverse samples, some of his justifications are more convincing than others. In particular, framin...
Performance Achievement and Analysis of Teaching during Choral Rehearsals

Eighty-three rehearsals and four final performances of two high schools' beginning and advanced choruses were videotaped to identify rehearsal behaviors and to evaluate performance achievement in r...
Health care utilization and receipt of cholesterol testing by veterans with and those without mental illness.

Abstract Objective We examined the relationship between mental illness, health care utilization and rates of cholesterol testing. Methods We conducted a retrospective cohort study using Veterans Affairs (VA) administrative data on 64,490 United States veterans who used VA New England Health Care System outpatient services between January 1998 and June 2001. A total of 10,100 veterans (15.7%) had a mental illness treated with medication. We examined the interaction between mental illness and outpatient service utilization with respect to the likelihood of receiving a cholesterol test, adjusting for major demographic and clinical covariates. Results Among veterans using VA outpatient services infrequently, those with mental illness were less likely than non-mentally ill control subjects to receive a cholesterol test during the study period (first quartile adjusted OR=0.45, 95% CI=0.37–0.54; second quartile adjusted OR=0.50, 95% CI=0.45–0.57). Mentally ill subjects with more frequent utilization of VA services were as likely as (third quartile adjusted OR=1.01, 95% CI=0.91–1.13) or more likely than (fourth quartile adjusted OR=2.73, 95% CI=2.46–3.03) non-mentally ill subjects to receive cholesterol testing. Conclusions Mental illness was associated with a lower likelihood of cholesterol testing in subjects who used fewer VA outpatient services. The observed disparity attenuated at higher levels of service utilization.
Lines and dipoles are efficiently detected

11/28/06) Watson, Barlow, & Robson (1983) rated patterns by contrast energy threshold and found a 7 cpd Gabor to be best. Watson (2000) plotted the contrast energy thresholds for the 43 Modelfest stimuli and found a Gaussian spot with a standard deviation (SD) of 2.1 arc min was best. When he compensated for contrast sensitivity, the best spot was the smallest one (SD = 1.05 min) and the overall best stimulus was the “one octave” (window SD = 2.1 min) 16 cpd Gabor. When he accounted for spatial summation in addition to contrast sensitivity, the spots and the Gabors were similar in performance and the best stimulus (but not significantly different) was the long (window SD = 30 min), narrow (1 pixel = 0.5 min) line. Using Modelfest-like methods, we have measured the detectability of lines as a function of length (2, 6, 18, 54 min) and width (0.5, 1, 2 min) and also have compared the detectability of lines (8 x 0.5 min) with that of dipoles (2 adjacent 8 x 0.5 min lines of equal and opposite contrast). We found that short lines can have contrast energy thresholds as low as those of spots, and that when contrast sensitivity is taken into account, dipole thresholds can be as low as those of lines. We also found that the introduction of fixation marks close to the small patterns could lower the thresholds as much as 3 dB, suggesting that spatial uncertainty may have played an important role in the detection of small patterns in the Modelfest experiments. Introduction (9/08/08) “What does the eye see best?” is the title of the 1983 Nature article by Watson, Barlow, & Robson. “Best” meant detected most efficiently relative to the ideal observer limited only by quantum noise. They showed that the best pattern is then the one with the lowest contrast energy threshold. The contrast energy of a discrete space-time contrast signal c(x, y, t) is E = dx dy dt Σ c(x, y, t) 2 where dx is the pixel width, dy is the pixel height, and dt is the pixel duration. We use a decibel scale for contrast energy using the lowest threshold from the Watson, Barlow, and Robson study as the zero point. dBB = 10 log 10 (E/E 0 ) E 0 = 10 -6 deg 2 sec Watson, Barlow, & Robson measured contrast energy thresholds for Gabors varying in spatial and temporal frequency, fX and fT, and horizontal and vertical and temporal standard deviations, sX, sY, and sT, and squares varying in size. The best stimulus was a Gabor whose contrast over space (x, y) and time (t) was sin[ 2 pi ( fX x + fT t)] exp[ – 0.5 ((x/sX) 2 + (y/sY) 2 +(t/sT) 2 ) ]
How do we measure a residual tumor size in histopathology (the gold standard) after neoadjuvant chemotherapy

Accurate reporting of the residual tumor size by pathologists after neoadjuvant chemotherapy is an important component of a breast cancer. Recent literature reported comparisons regarding the accuracy of clinical and radiological residual tumor size findings using the histopathology as a "gold standard". However, the histopathological methods of measuring the residual tumor size are not standardized. Most pathologists use the tumor size measured by the gross examination. We collected 32 patient samples and compared the residual tumor size by gross and microscopic pathologic examinations. Using microscopic tumor size as the gold standard, our study showed gross tumor size is overestimated in 25%, underestimated in 56% and correlated to the final microscopic tumor size in 19% of the cases after neoadjuvant chemotherapy. Determining accurate residual tumor size to estimate pathologic response to chemotherapy is essential. We attempted to provide guidelines for pathology reporting post-neoadjuvant chemotherapy on breast cancers.
Caroline Bond Day (1889–1948): A Black Woman Outsider Within Physical Anthropology

This article examines the significance of Caroline Bond Day's vindicationist anthropological work on mixed-race families early in the 20th century. Day used the techniques of physical anthropology to demonstrate that mixed-race African Americans were in no way inherently deformed or inferior. Using Day's published work and unpublished correspondence, I show that her study was noteworthy for two reasons. First, unlike most other anthropologists of her time, but presaging later scholars, she studied her own family and social world, a perspective that both gave her unique data unavailable to others and removed barriers between herself and her subjects. Second, as a mixed-race African American woman, she found herself not only fighting preconceptions about the racial inferiority of African Americans but also serving as a liaison between her research subjects and mainstream, White-dominated physical anthropology. This article argues that Day's importance as a scholar lies not only in her argument against racial inferiority but also in the outsider-within status that allowed her to make her case within academic anthropology in the early 20th century.
Features to consider in a data warehousing system

Evaluating and assessing the important distinctions between data processing capability and data currency.
Sexual Prejudice Among Heterosexual College Men as a Predictor of Condom Attitudes

Heterosexual male college students (N = 100) (average age = 19.7; 43% European American; 39% Christian) from the southwestern U.S. completed surveys in order to test a model predicting condom attitudes from religiosity, gender role attitudes, sexual prejudice, and the belief that “AIDS is a gay disease.” In the final model, those who reported more religiosity, more traditional gender role attitudes, and greater anxiety about interacting with gay men also reported feeling their core values and beliefs were threatened by gay men. In turn, men who felt strongly threatened in this way more strongly endorsed the belief that “AIDS is a gay disease,” and stronger endorsement of this belief was associated with more negative attitudes about condoms and condom use.
Lupeol and 30-norlupan-3β-ol-20-one from the coating of the castor bean (Ricinus communi L.)

Abstract Lupeol has been isolated and identified as the major constituent of the white crystalline coating of the Ricinus communi L. The isolation and identification of 30-Norlupan-3β-ol-20-one is also described.
Nitrogen and Oxygen Abundance Variations in the Outer Ejecta of η Carinae: Evidence for Recent Chemical Enrichment

We present optical spectra of the ionized "outer ejecta" of η Car that reveal differences in chemical composition at various positions. In particular, young condensations just outside the dusty Homunculus nebula show strong nitrogen lines and little or no oxygen, but farther away, nitrogen lines weaken and oxygen lines become stronger. The observed variations in the apparent N/O ratio may signify either that the various blobs were ejected with different abundances or, more likely, that the more distant condensations are interacting with normal composition material. The second hypothesis is supported by various other clues involving kinematics and X-ray emission and would suggest that η Car is enveloped in a "cocoon" deposited by previous stellar wind mass loss. In particular, all emission features in which we detect strong oxygen lines are coincident with or outside the soft X-ray shell. In either case, the observed abundance variations suggest that η Car's ejection of nitrogen-rich material is a recent phenomenon, taking place in just the last few thousand years. Thus, η Car may be at a critical stage of evolution when ashes of the CNO cycle have just appeared at its surface. Finally, these spectra reveal some extremely fast nitrogen-rich material, with Doppler velocities up to 3200 km s-1 and actual space velocities that may be much higher. This is the fastest material yet seen in η Car's nebula, but with unknown projection angles its age is uncertain.
Deaminocanavanine formation from canavanine

Abstract The rate of spontaneous canavanine breakdown to deaminocanavanine and NH 3 is affected by temperature, substrate concentration, solvent system, time, and various divalent cations. Ammonium ions may accelerate canavanine decomposition. Canavanine is most stable as a dilute aqueous solution at 4° or in the presence of 0·1 N HCl. When HCl is omitted, deaminocanavanine formation increases as the temperature is elevated from 4 to 37°. In aqueous ethanol or on adding NH 4 OH to 100 mM, deaminocanavanine formation is increased. Deaminocanavanine does not appear to play a significant role in the nitrogen metabolism of jack bean.
Fourth-order elastic constants of β-brass

Combinations of the fourth-order elastic constants of β-brass were calculated using the measured second-order and third-order elastic constants and the expressions for the effective elastic constants of a cubic crystal obtained from finite-strain theory. The present calculations show that the Cauchy relations for the fourth-order elastic constants in β-brass are not satisfied. This implies that noncentral or many-body forces occur in this material. We consider two alloys. The higher-Zn alloy shows lower magnitudes of the fourth-order elastic constants and a larger Cauchy discrepancy.
SEC enforcement activities: A survey and critical perspective

Abstract SEC enforcement activities against registrant firms and their auditors are codified in a series of accounting and auditing enforcement releases (AAERs). This paper reviews and analyses all of the AAERs and provides summary information about the registrant, their auditors, the types of violations made, and the sanctions required by the SEC. In addition, sanctions directed at larger firms for whom we could obtain additional financial statement information are analysed. Our analysis indicated that, among large registrants, those firms receiving sanctions were significantly larger and had a higher proportion of opinion qualifications than their industry counterparts while their auditors received SEC sanctions only a small portion of the time. Practice suspensions, CPE hours, peer review and censures or injunctions were the most common SEC penalties against auditors. Future SEC enforcement powers under the newly-enacted Securities Enforcement Remedies and Penny Stock Reform Act of 1990 are also discussed.
Effect of cortisol on [3H] 1,25-dihydroxyvitamin D3 uptake and 1,25-dihydroxyvitamin D3-induced DNA-dependent RNA polymerase activity in chick intestinal cells

The influence of cortisol on intestinal DNA-dependent RNA polymerase activity was studied in purified nuclei of vitamin D-deficient or 1,25-dihydroxyvitamin D3-treated chicks. Six- to 7-week-old vitamin D-deficient cockerels were given 5 mg of cortisol or vehicle intraperitoneally 24 and 48 hours before sacrifice. Three hours before sacrifice, 200 ng of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) was administered intracardially. Cortisol did not alter the uptake or metabolism of 1,25(OH)2D3 in the intestinal mucosa. After a 200 ng dose of 1,25(OH)2D3 thein situ intestinal ligated loop technique revealed a 39% increase in calcium absorption compared to control birds (P<0.001). The administration of cortisol (5 mg) to chickens given 1,25(OH)2D3, however, resulted in a significant decrease in intestinal calcium transportin vivo (P<0.0025). When intestinal nuclei were prepared from birds treated in a manner identical with that described above, 1,25(OH)2D3-treated and 1,25(OH)2D3 plus cortisol-treated chicks had intestinal RNA polymerase II transcriptional activities that were significantly greater than those of vitamin D-deficient controls (P≤0.02,P≤0.005). There was no difference between RNA polymerase II and I+III activities of the 1,25(OH)2D3-treated birds and that of the cortisol plus 1,25(OH)2D3-treated birds. Vitamin D-deficient chicks treated with cortisol alone showed RNA polymerase I+III activity that was significantly higher (P≤0.01) than that of birds treated with vehicle alone. As transcription is not altered by cortisol following 1,25(OH)2D3 treatment, we suggest that cortisol may inhibit intestinal calcium transport by altering posttranscriptional or other events such as basolateral membrane calcium transport.
Transport of Gamma rays through an infinite homogeneousore medium

Abstract A discrete-ordinates transport code has been used to transport gamma rays from the decay of the naturally occurring radioactive isotopes of potassium, uranium, and thorium through an infinite homogeneous medium. Parametric studies varying the medium type (i.e., shale and sandstone), porosity, and saturation were made to determine their effects on the calculated gamma-ray spectra. In addition, the effect on the gamma-ray spectra of trace quantities of heavy elements was studied by varying the uranium concentration in the formation from 0% to 6% by weight.
Citation “snapshot” of three leading international auditing journals

Purpose – This paper aims to examine the “impact” of three leading international auditing journals via citation analysis.Design/methodology/approach – A Google Scholar citation analysis was conducted for the period 2001‐2006 for Auditing: A Journal of Practice & Theory, Managerial Auditing Journal, and International Journal of Auditing. The top ten citations from each of these journals were used to analyze relative journal citation frequency, publication topics, and leading authors.Findings – Auditing: A Journal of Practice & Theory has a statistically significant higher level of average number of citations than the other two journals in this paper. Nine topics accounted for 80 percent of the articles examined. Four individuals are author/co‐author of two papers and three of these individuals published in two of the three journals.Originality/value – This is the first paper to examine recent citations from these three journals. The research provides a basis for an author to evaluate potential “impact” fro...
The diffuse reflectance spectra of some titanium oxides

Diffuse reflectance spectra in the visible and near ultraviolet are reported for TiO, Ti2O3, and the anatase, rutile and natural brookite crystalline modifications of TiO2. Results are interpreted qualitatively in the light of crystal field theory.
Mechano-chemistry of the enzyme Guanylate Kinase

We address the coupling of mechanics and chemistry in an enzyme through equilibrium experiments where we mechanically deform the enzyme and measure the effect on the chemical reaction it catalyzes. We use the DNA molecular spring method to exert stresses at three different specific locations on the enzyme Guanylate Kinase, and for each case determine the changes in substrates binding affinities and catalytic rate. We find that the enzyme kinetics parameters can be affected separately, depending on where the mechanical stress is applied. For one configuration the applied stress mainly affects the catalytic rate kcat, for another it mainly affects the binding affinity of the substrate GMP. These experiments show that a stress applied by pulling two residues on the surface of the protein generally results in a strain propagating into the structure.
Ultrasound-induced cavitation: applications in drug and gene delivery.

Ultrasound, which has been conventionally used for diagnostics until recently, is now being extensively used for drug and gene delivery. This transformation has come about primarily due to ultrasound-mediated acoustic cavitation – particularly transient cavitation. Acoustic cavitation has been used to facilitate the delivery of small molecules, as well as macromolecules, including proteins and DNA. Controlled generation of cavitation has also been used for targeting drugs to diseased tissues, including skin, brain, eyes and endothelium. Ultrasound has also been employed for the treatment of several diseases, including thromboembolism, arteriosclerosis and cancer. This review provides a detailed account of mechanisms, current status and future prospects of ultrasonic cavitation in drug and gene delivery applications.
Chemical binding effects in the thermalization of neutrons

In an earlier paper we extracted an asymptotic series solution in half-integral powers of (kTE) from the Boltzmann transport equation for neutrons coming into thermal equilibrium with a moderating material. In this paper we consider the series in detail for moderators having simple crystalline structure, or in which vibrational modes predominate, and give the coefficients of the series explicitly in terms of moments of the frequency spectrum of crystal vibrations. Our calculations indicate that the neutron density in the asymptotic region increases as one hardens the spectrum of crystal vibrations, whence the “hardness” of the neutron spectrum increases, too. We also discuss some aspects of the mass-expansion for these systems, and compare our calculations with those of other workers, and with typical experimental data for thermalization in water. Finally, we discuss the asymptotic expansion for moments of the scattering kernel and for ξσ_s, the slowing down power.
Dynamics of Conformational Transitions during KcsA Gating from EPR and Solution NMR Experiments

Despite its apparent simplicity, the potassium channel KcsA possesses a relatively complex gating cycle. Previous studies show conformational changes at the inner gate with an increase in distance from the central axis of symmetry when activated. These changes, coupled to rearrangements at the selectivity filter, are hypothesized to underlie activation, inactivation and modal gating. Defining the dynamic properties of the conformational wave linking the inner gate and selectivity filter is a critical step in understanding the mechanism of gating and permeation in K+ channels.Here, we have used CW and DEER Electron Paramagnetic Resonance to measure the opening of the inner gate and NMR to investigate the dynamics of the backbone of KcsA in a pH dependent manner. KcsA G116C was spin-labeled and reconstituted into liposomes or DDM micelles for EPR studies. NMR studies used wild type KcsA Δ125 in micelles (from pH7 to pH3 in 0.5 unit increments) with 2H/15N labeling and a TROSY pulse sequence. Pilot experiments investigating dynamics used a CPMG pulse sequence at pH7 and pH3.The extent of conformational dynamics from the inner gate ranged from 10.0 A (closed, pH7) to 23.7 A (open, pH3) with pH activation. Distance changes were abrupt near the pKa of activation (pH 3.9). Importantly, an observed increase in the width of the population distribution, and hence dynamics, was also observed at this point. Preliminary NMR experiments confirm that this region possesses distinct chemical shifts from a closed versus an open, inactivated state.Ongoing experiments target the process of backbone dynamics at different regions of KcsA. New pulse sequence schemes and kinetic gating mutants of KcsA are being studied to isolate the multiple dynamics components that define KcsA modal gating.
Sodium and Potassium Triisopropylbenzenethiolates: Influence on Solid-State Structure by Metal and Donor

The synthesis and characterization of a family of sodium and potassium thiolates [A(donor)S(Trip)]n (A = Na, K; Trip = 2,4,6-i-Pr3C6H2, n = 1−∞) is described. [Na(PMDTA)S(Trip)]2, 1 (PMDTA = N,N,N‘,N‘‘,N‘‘-pentamethyldiethylenetriamine), [(NaS(Trip))2(Na(Et2O)S(Trip))4]·0.5 solvent, 2, [Na(TMEDA)S(Trip)]∞, 3 (TMEDA = N,N,N‘,N‘-tetramethylethylenediamine), [Na(THF)S(Trip)]n, 4 (n = 6 or ∞), [K(dibenzo-18-crown-6)(THF)S(Trip)]·THF, 5, [(KS(Trip))2(K(THF)S(Trip))2(K(THF)2S(Trip))2], 6, [K(THF)S(Trip)]∞, 7, [(K(THF)S(Trip))2(K(TMEDA)S(Trip))2(KS(Trip))2]·THF, 8, and [K(PMDTA)S(Trip)]∞, 9, were synthesized by treatment of HS(Trip) with NaH or KH along with the addition of various donors. The target molecules were characterized by IR, 1H NMR, and depending on solubility, 13C NMR spectroscopy and melting point. Compounds 1−3 and 5−9 were also characterized by single-crystal X-ray crystallography. Analysis of structural data clearly indicates that the structural chemistry of the target molecules can be influenced...
Fractional Regression Hot Deck Imputation Weight Adjustment

Fractional regression hot deck imputation (FRHDI) imputes multiple values for each instance of a missing dependent variable. The imputed values are equal to the predicted value plus multiple random residuals. Fractional weights enable variance estimation and preserve correlations. In some circumstances with some starting weight values, existing procedures for computing FRHDI weights can produce negative values. We discuss procedures for constructing non-negative adjusted fractional weights for FRHDI and study performance of the algorithm using simulation. The algorithm can be used effectively with FRDHI procedures for handling missing data in the context of a complex sample survey.
Reentry and the (Unmet) Needs of Women.

The number of women under community-based criminal justice supervision in the U.S. has reached an all-time high. Because of this, there is an increased need for programs meant to address the unique needs of reentry women. In this article we examine a sample of 155 such programs to determine whether currently available reentry programs in the 10 largest metropolitan areas of the U.S. are able to meet the needs of reentry women. We find that currently available reentry programs do not sufficiently meet the needs of postincarceration women.
Vivisectionists strike back

The complex issue of animal experimentation should not be dumbed down in the face of violent opposition, argues Andrew Read, reviewing a new polemic on the US experience.
Release of corrosion products by F‐75 cobalt base alloy in the rat. III: Effects of a carbon surface coating

A pyrolytic carbon coating was applied to F-75 chromium-cobalt-molybdenum alloy in an effort to reduce the release of corrosion products in vivo. After intramuscular implantation in the rat, a complex pattern of serum and urine concentration elevations of chromium, cobalt, and nickel was seen. The carbon-coated implants released more chromium and cobalt than uncoated controls, as seen by significantly elevated metal concentrations in serum and urine. Animals receiving carbon-coated implants showed a high rate of recurrent implant site inflammation. Neoplastic infiltration of the implant site occurred in 3 out of 24 animals with coated implants, but not in any of the 16 animals which received either uncoated F-75 microsphere or poly(ethylene) particulate implants.
Mechanism of elongation of primed DNA by DNA polymerase delta, proliferating cell nuclear antigen, and activator 1.

Abstract In the presence of a single-stranded-DNA-binding protein (SSB), the elongation of primed DNA templates by DNA polymerase delta (pol delta) is dependent on ATP and two protein factors, activator 1 (A1) and proliferating cell nuclear antigen (PCNA). We have examined the interaction of these proteins with (dA)4500.(dT)12-18 by measuring their ability to form stable complexes with this DNA. In the presence of ATP, A1, PCNA, and pol delta formed a stable complex with DNA that could be isolated by gel filtration. Incubation of the isolated complex with dTTP resulted in the synthesis of poly(dT). While ATP was required for the formation of this complex, it was not required for the subsequent elongation of DNA. The temporal requirements for complex formation were determined. A1 was found to bind first, followed by the ATP-dependent addition of PCNA to the A1.DNA complex, while pol delta was added last. Each of these complexes could be isolated by gel filtration, indicating that they possessed a high degree of stability. The binding of PCNA to the A1-SSB-coated primed DNA occurred with adenosine 5'-[gamma-thio]triphosphate as well as ATP. However, the binding of pol delta to the PCNA.A1-DNA complex was observed only when the latter complex was formed in the presence of ATP. The complete complex was formed after incubation at 37 degrees C for 2 min, whereas no complex was detected after incubation at 0 degree C. These results indicate that these proteins act in a manner analogous to the accessory proteins that play critical roles in the elongation reaction catalyzed by T4 phage DNA polymerase and Escherichia coli DNA polymerase III.
Initial Damage in Human Interphase Chromosomes from Alpha Particles with Linear Energy Transfers Relevant to Radon Exposure

To determine the efficiency at which {alpha} particles at LETs chosen to simulate exposure to radon progeny break chromosomes, the premature chromosome condensation technique was used to measure breaks soon after irradiation. Noncycling human fibroblasts were irradiated with graded doses of monoenergetic {alpha} particles accelerated to produce LETs of 90, 120, 150, 180 and 200 keV/pm at the midpoint of the cell nuclei. Premature chromosome condensation was initiated immediately after irradiation and cells were scored for the total number of prematurely condensed chromosomes and fragments per cell. Similar experiments were conducted with 250 kVp X rays for comparison. Irradiation with {alpha} particles produced 8.6 to 13.1 excess fragments per gray, while X rays produced 5.8 excess fragments, resulting in RBEs around 2. Calculations of the number of breaks produced on average by a single particle traversal of a cell nucleus indicated that at the LETs tested more than one break was produced by each traversal, the maximum being that produced by 180 keV/{mu}m {alpha} particles. When chromosome aberrations are scored at metaphase after high-LET irradiation, RBEs considerably greater than those recorded here have been reported. These results showing relatively small differences in initial break levels for {alpha} particles in themore » LET range of the radon progeny relative to X rays indicate that the great aberration frequencies are not due principally to an increase in breakage efficiency, but interactions between breaks along the same particle track are important. 16 refs., 4 figs.« less
Applied regression analysis bibliography update 1994-97

The 25-page Bibliography in Applied Regression Analysis, 2nd edition, by N.R Draper and H. Smith, published by Wiley in 1981, was previously extended by a list of selected references available during 1988-89,1990-91 and 1992-93, plus a few older references. See Communications in Statistics-Theory and Methods,19(4), 1205-1229 (1990), 21(9), 2415-2437 (1992) and 23(9), 2701-2731 (1994). Here is a further update covering the years 1994-97. As before, items were chosen on the basis of their perceived relevance to practical applications (sometimes rather widely interpreted). The classification system used here is that of the 3rd edition of the book, published in 1998
Observations on emerging patterns of asthma in our society

Epidemiologic studies of temporal and geographic variation in asthma morbidity have identified asthma as an important public health concern. Knowledge gained from these studies has resulted in intense focus on this condition by agencies such as the National Institutes of Health and the World Health Organization. In this report, studies of recent asthma trends and patterns are explored. These studies show increases in US prevalence through 1994. Data on measures of morbidity show complex longitudinal patterns but are notable for large differences in emergency department services and hospitalizations by age and race. Very recent trends for US asthma mortality suggest widening of an existing racial gap. Limited comparisons are possible between these US trends and international trends but do suggest that US increases in prevalence and mortality rates may reflect world-wide patterns. Also, within the US, it is clear that geographic variation exists in asthma prevalence, morbidity, and mortality rates. Changes in certain environmental risk factors and exposures may contribute to recent trends, but little information is available relating specific risk factors to either longitudinal asthma trends, geographic variability, or high-risk populations.
Electrical-hydraulic relationships observed for unconsolidated sediments

[1] We use complex conductivity measurements to predict the hydraulic conductivity (K) of unconsolidated materials. The samples include natural sediments and artificial sand/clay mixtures. We apply the Borner et al. [1996] model, which is based on the Kozeny-Carman equation and incorporates electrical estimates of formation factor (F) and specific surface area per unit volume-to-porosity ratio (Spor), from the real (σ′) and imaginary (σ″) conductivity components respectively. We find that K correlates with σ″ but shows no correlation with F, which we attribute to the wide range in grain size for these materials. The Borner model appears primarily dependent on the K - σ″ relation. The relationship between σ″ and Spor is nonlinear and appears to depend upon material type. Further examination shows that σ″ is well correlated with effective grain size (d10) and is relatively independent of the material type. We propose a simple Hazen-type equation in which the effective grain size is estimated from σ″. This simple model provides order of magnitude estimates of K for a range of unconsolidated sediments.
Dietary Green Tea Extract Lowers Plasma and Hepatic Triglycerides and Decreases the Expression of Sterol Regulatory Element-Binding Protein-1c mRNA and Its Responsive Genes in Fructose-Fed, Ovariectomized Rats

The objective of this study was to determine whether green tea (GT) inhibits the expression of genes regulating hepatic lipogenesis and intestinal lipid transport in fructose-fed ovariectomized (OX) rats. OX rats were assigned to: 1) a control group (S) fed the AIN-93G diet with corn starch as the major carbohydrate source; 2) another control group (F) fed the same diet but containing fructose at 60% as the major carbohydrate source; 3) a group fed the F diet but containing 0.5% GT; and 4) a group fed the F diet containing 1% GT. At 6 wk, plasma and liver triglyceride (TG) and cholesterol and expression of liver sterol regulatory element-binding protein-1c (SREBP-1c) and selected genes involved in lipogenesis and lipid transport were measured. Fructose elevated plasma TG and cholesterol compared with the S group. GT at 0.5 and 1.0% markedly lowered plasma and liver TG. Fructose increased the expression of SREBP-1c, fatty acid synthase, and stearoyl-CoA desaturase 1 mRNA in the liver, whereas GT decreased the expression of these lipogenic genes. Similarly, fructose increased the abundance of hepatic 3-hydroxy-3-methyl-glutaryl-CoA reductase mRNA, whereas GT significantly decreased its expression. GT did not alter the expression of scavenger receptor class B, type 1, microsomal TG transfer protein, and apobec 1 in the liver and intestine. The results suggest that the lipid-lowering effect of GT is mediated partly by its inhibition of hepatic lipogenesis involving SREBP-1c and its responsive genes without affecting lipoprotein assembly.
Room-temperature direct bandgap electroluminesence from Ge-on-Si light-emitting diodes

We report what we believe to be the first demonstration of direct bandgap electroluminescence (EL) from Ge/Si heterojunction light-emitting diodes (LEDs) at room temperature. In-plane biaxial tensile strain is used to engineer the band structure of Ge to enhance the direct gap luminescence efficiency by increasing the injected electron population in the direct Γ valley. Room-temperature EL is observed at the direct gap energy from a Ge/Si p-i-n diode exhibiting the same characteristics of the direct gap photoluminescence of Ge. The integral direct gap EL intensity increases superlinearly with electrical current owing to an indirect valley filling effect. These results indicate a promising future of tensile-strained Ge-on-Si for electrically pumped, monolithically integrated light emitters on Si.
The Political Economy of Social Organization Registration in China

The Chinese government uses legal registration to manage and control the rise of social organizations. To avoid negative government attention, organizations might be expected to actively pursue such registration. However, in-depth field research of Chinese NGOs in three issue areas (environmental protection, HIV/AIDS prevention, and gay and lesbian rights) reveals that this is not always the case. There are many conflicting political and economic incentives for both NGOs and government, complicating understandings of social organization registration in China. By shedding light on the process of registration, this article reveals the complexities of state–society relations and demonstrates the difficulties for social organizations to avoid significant government interference.
A modified comorbidity index for hematopoietic cell transplantation

A recent validation analysis at our center among allogeneic hematopoietic cell transplant (HCT) recipients did not find the HCT-specific comorbidity index (HCT-CI) to clearly segregate patient's transplant-related risk. We hypothesized that the discriminating and predictive power of the HCT-CI for mortality could be improved by eliminating the assignment of categorical weights to comorbidities and instead replacing them with hazard ratios (HR) from a Fine and Gray adjusted regression model. This approach allowed us to look carefully at each component of the comorbidity index. We developed the modified comorbidity index (MCI) using a cohort of 444 adult allogeneic HCT recipients using a pure multiplicative model. Compared with low-risk patients, the HR for non-relapse mortality (NRM) using the HCT-CI was 1.3 (95% confidence intervals, 0.7–2.4) for intermediate risk and 1.6 (0.9–2.8) for high-risk patients, and with the MCI was 1.6 (0.9–2.8) and 2.7 (1.5–5.0), respectively. In conclusion, we are introducing the MCI which may have higher discriminating and predictive power for overall survival and NRM. Validation of the HCT-CI and the MCI in larger and separate cohorts of HCT recipients is still needed.