cssi/SciSciGPT-SciSciNet huggingface dataset:
Condom Use, Disclosure, and Risk for Unprotected Sex in HIV-Negative Midlife and Older Men Who Have Sex With Men

Sexual risk behaviors account for most HIV infections in men who have sex with men (MSM), and the risk of exposure from each sexual encounter increases with age. The focus of this study was to investigate which behaviors in midlife and older MSM influence their sexual risk/protection. Cross-sectional data were collected from a community-based sample of 802 MSM aged 40 years and older from community venues (e.g., bars) who completed an anonymous questionnaire. Data from a subset of 420 MSM who were HIV-negative (aged 40-81 years) were used to investigate which behaviors were associated with greater risk for unprotected anal sex. Regression analyses indicated that erection difficulties (odds ratio [OR] = 4.7; 95% confidence interval [CI] = 1.8-12.2), practicing safe sex with outside partners but not with one's primary partner (OR = 0.54; 95% CI = 0.3-0.94), and recreational drug use (OR = 2.6; 95% CI = 1.3-5.1) were associated with higher risk for unprotected receptive anal intercourse. Younger age (OR = 0.96; 95% CI = 0.9- 0.9), not telling partners about HIV status (OR = 3.2; 95% CI = 1.5-6.5), finding partners in backrooms/sex clubs (OR = 2.8; 95% CI = 1.1- 6.8), and erection difficulties (OR = 10.3; 95% CI = 2.8-37.8) were associated with higher risk for unprotected insertive anal intercourse. These data indicate there may be certain factors specific to older MSM that influence their sexual risk taking behaviors. Programs may be more effective if they are tailored for older cohorts of MSM and address interpersonal communication, erection problems, and substance use to reduce health risks and promote healthier lifestyles.
The Impact of Community Development Corporations on Neighborhood Housing Markets: Modeling Appreciation

Housing investment activities of community development corporations (CDCs) can be associated with a positive impact on the residential real estate market within their respective service area. Relying on a pseudo-experimental approach, the appreciation rate of single-family housing in CDC treatment and comparison areas is tested with a traditional hedonic model with pooled data. The results suggest that the area that is served by the 12 established CDCs operating in Center Township in the city of Indianapolis experienced a higher overall appreciation in the mean residential home value from 1987 to 2000 than did a comparison area in Center Township not served by CDCs.
Kinetics of Polymer Conformational Changes and Its Role in Flocculation

The kinetics of conformational changes of a series of partially hydrolyzed polyacrylamides (HPAM) adsorbed on alumina in aqueous solutions was studied along with the flocculation of alumina. After the polymer was adsorbed, the conformation of the adsorbed polymer was changed by shifting the suspension pH. It was found that the kinetics of the polymer conformational change was dependent upon the hydrolysis degree and the molecular weight. It was found that while under fixed pH conditions the flocculation continuously decreased apparently due to floc breakage; under shifted pH conditions (from low to high) it went through a maximum as a function of time. When the effects of floc breakage caused by agitation are isolated and accounted for the flocculation is found to correlate well with the conformational changes in the system. It is proposed that the unusual flocculation time dependence obtained under the shifted pH condition is caused by the combination of the beneficial effect of the predominant polymer conformational changes and the detrimental effect of floc breakage by agitation.
SYMPOSIUM ON MEAT FLAVOR FACTORS INFLUENCING THE FLAVOR OF MUSCLE FOODS

A review of the various genetic, environmental and processing factors which influence the expression of flavor in muscle foods, from animal, avain and aquatic sources, is presented. Special emphasis is given to such variables as species, breed, sex, age, nutrition, primary and further processing operations. Although a variety of factors is known to influence the flavor of muscle foods, no single one or group of factors can be assigned the role of principal influencer. In fresh muscle foods, genetic as well as environmental factors are probably most important. Of the genetic factors, there is little doubt that species exerts the most pronounced effect on flavor. Nutritional effects are the most important of the environmental factors influencing flavor. Primary processing operations (i.e., carcass washing techniques, freezing) can affect the flavor of fresh muscle foods. In further processed muscle foods, the flavor is most affected by those factors which influence product composition.
Diffusing capacity in bituminous coal miners.

Pulmonary diffusing capacity (DL) was measured in 133 underground bituminous coal miners at rest and during moderate exercise by the steady state end tidal sampling method. The average DL. among cigarette smoking miners was lower than among nonsmoking miners of comparable age and years of underground mining. In contrast to the smoking miners, a large majority of nonsmoking miners had normal DL. This difference in DL could not be explained by the presence of bronchitis, airway obstruction, or radiographic evidence of coal workers' pneumoconiosis (CWP), although bronchitis and CWP were more frequent among the smoking miners. It is doubtful that the measurement of DL would be a useful screening test for occupational disease among cigarette smoking coal miners, since it is significantly affected by smoking.
Ultrafast orientational dynamics of nanoconfined benzene.

Ultrafast optical Kerr effect spectroscopy has been used to study the orientational dynamics of benzene and benzene-d6 confined in nanoporous sol−gel glass monoliths with a range of average pore sizes. All of the observed orientational diffusion of confined benzene is found to occur on a slower time scale than in the bulk, even in pores with diameters that are significantly larger than a benzene molecule. The orientational dynamics of benzene-d6 are found to be inhibited to a lesser extent than those of benzene, which is attributed to the differences in wetting properties of the two liquids on silica. The decays are fit well by a sum of two exponentials, the faster of which depends on pore size. Similar results are found in pores that have been modified with trimethylsilyl groups, although the relaxation is faster than in unmodified pores. Comparison to Raman line width data for confined benzene-d6 suggests that the liquid exhibits significant structuring at the pore walls, with the benzene molecules lyin...
Tensile and Fatigue Behavior of Aluminum Oxide Fiber Reinforced Magnesium Composites: Part II. Alloying Effects

The effect of matrix alloy additions on mechanical properties was examined by comparing the tensile and fatigue properties of commercially pure magnesium and ZE41A (Mg-4.25 Zn-0.5 Zr-1.25 RE) which were both reinforced with FP aluminum oxide fibers. The alloy additions were found to improve the off-axis properties but decrease the axial properties. This was brought about by an increase in the matrix and interfacial strengths and a decrease in the fiber strength. It was also determined that the reaction zone in both materials was MgO and that strengthening of the interface was due to an increased particle size and/or a thicker reaction zone and not to any segregation of alloying elements to the interface.
Topological insulator nanostructures

Topological insulators provide a gateway to investigate fundamental quantum behaviours of exotic quasi-particles as well as the promise to revolutionize modern technology. This is due to their unique surface states that are robust against time reversal perturbation and exhibit unique spin-momentum locking property. Enhancing the surface state signal in proportion to the bulk of the material is critical to study the surface states and for future electronics applications. This can be achieved by making topological insulators into nanostructures, which have large surface to volume ratios thus maximizing the topological surface state signal. This article reviews the recent progress made in topological insulator nanostructures including chemical and physical synthesis techniques to make topological insulator nanostructures, notable transport experiments, and current efforts to protect the surface states from degradation. Lastly, future transport studies using topological insulator nanostructures and various chemical methods to tune their materials properties for diverse electronic applications are suggested. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Absorption Equilibrium and Kinetics for Ethylene−Ethane Separation with a Novel Solvent

A novel solvent system consisting of CuCl/aniline/n-methyl pyrrolidone was evaluated for the reactive absorption of ethylene. Equilibrium olefin loadings significantly exceeded physical solubility values. The equilibrium ethylene−ethane selectivity was a strong function of the gas phase total pressure. Kinetic behavior was accurately described by an instantaneous reversible mechanism. The solvent exhibited acceptable chemical stability during the experimental tests.
The structure of monomial circulant matrices

Consider the generalized circulant matrices recently introduced by P. J. Davis and K. Wang, where row i is obtained from row 1 by permuting the entries and also multiplying by scaling factors. When such families are (like circulants) closed under multiplication, they can be reduced to certain standard forms that are in fact related to twisted group algebras and group cohomology. For real matrices or complex matrices, there are only finitely many such standard forms for each size. Similar results hold for the appropriate generalizations of g-circulants. In particular, in each case (for complex matrices) we can describe the determinant as a function of the first-row entries: it is a product of powers of various smaller determinants, and up to (explicit) scaling factors the list of entries in these determinants is a unitary transformation of the original first-row entries. Some of the ideas hold for even more generalized forms of circulants.
The DNA-binding Domain of the Yeast Spt10p Activator Includes a Zinc Finger That Is Homologous to Foamy Virus Integrase

Abstract The yeast SPT10 gene encodes a putative histone acetyltransferase that binds specifically to pairs of upstream activating sequence (UAS) elements found only in the histone gene promoters. Here, we demonstrate that the DNA-binding domain of Spt10p is located between residues 283 and 396 and includes a His2-Cys2 zinc finger. The binding of Spt10p to the histone UAS is zinc-dependent and is disabled by a zinc finger mutation (C388S). The isolated DNA-binding domain binds to single histone UAS elements with high affinity. In contrast, full-length Spt10p binds with high affinity only to pairs of UAS elements with very strong positive cooperativity and is unable to bind to a single UAS element. This implies the presence of a “blocking” domain in full-length Spt10p, which forces it to search for a pair of UAS elements. Chromatin immunoprecipitation experiments indicate that, unlike wild-type Spt10p, the C388S protein does not bind to the promoter of the gene encoding histone H2A (HTA1) in vivo. The C388S mutant has a phenotype similar to that of the spt10Δ mutant: poor growth and global aberrations in gene expression. Thus, the C388S mutation disables the DNA-binding function of Spt10p in vitro and in vivo. The zinc finger of Spt10p is homologous to that of foamy virus integrase, perhaps suggesting that this integrase is also a sequence-specific DNA-binding protein.
Geometric and electronic structures of hydrogenated transition metal (Sc, Ti, Zr) clusters

We report first-principles electronic structure calculations of hydrogen adsorption and saturation on ${M}_{13}$ $(M=\text{Sc},\text{Ti},\text{Zr})$ clusters of icosahedral $({I}_{h})$ and cuboctahedral $({O}_{h})$ symmetries. Hydrogen saturation of the ${I}_{h}$ metal clusters yields energetically stable ${M}_{13}{\text{H}}_{20}$ and ${M}_{13}{\text{H}}_{30}$ systems compared to ${M}_{13}{\text{H}}_{14}$ and ${M}_{13}{\text{H}}_{24}$ systems for ${O}_{h}$ clusters. In all these clusters, the hydrogen adsorption involves dissociative chemisorption of ${\text{H}}_{2}$ molecules. Upon initial hydrogenation, the dissociated hydrogen atoms lie above either the triangular or quadrangular face of the metal cluster. A further increase in hydrogen saturation leads to the formation of bridged hydrogen bond between adjacent metal atoms. The role of the unfilled $d$ orbitals in imparting stability to the hydrogenated clusters is explored by examining their density of states (DOS) near the Fermi level. It has been found that the inverse correlation between the $d$-band center and the chemisorption energies is valid only at low hydrogen concentrations. At higher hydrogen coverages, the trend is reversed. The results illustrate that at high adsorbate concentrations or surface coverage, the correlation of the chemisorption energies with the $d$-band center of the pure metal cluster or nanoparticle may not be realistic but one has to take into account the changes in the $d$-orbital DOS due to the presence of coadsorbed molecules. To obtain further insights into the initial steps involved in hydrogen adsorption and dissociation, the transition states and activation energies of the ${M}_{13}{\text{H}}_{2}$ system have been determined and found to conform with the empirical Br\o{}nsted-Evans-Polanyi relationship. A highly intense infrared band in the $1000\char21{}1500\text{ }{\text{cm}}^{\ensuremath{-}1}$ region, associated with the adsorbed hydrogens in these hydrogenated metal clusters, may be used to experimentally monitor hydrogen coverage.
Changes in organ perfusion and weight ratios in post-simulated microgravity recovery.

Abstract Head-down tilt models have been used as ground-based simulations of microgravity. Our previous animal research has demonstrated that there are significant changes in fluid distribution within 2 h after placement in a 45° head-down tilt (45HDT) position and these changes in fluid distribution were still present after 14 days of 45HDT. Consequently, we investigated changes in fluid distribution during recovery from 16 days of 45HDT. Changes in radioactive tracer distribution and organ/body weight ratio were examined in rats randomly assigned to a 45HDT or prone control group. The 45HDT rats were suspended for 16 days and then allowed to recover at the prone position 0, 77, 101, or 125 h post-suspension. Animals were injected with technetium-labeled diethylenetriamine pentaacetate (99mTcDTPA, MW =492 amu , physical half-life of 6.02 h ) and then killed 30 min post-injection. Lungs, heart, liver, spleen, kidneys, and brain were harvested, weighed, and measured for radioactive counts. Statistical analyses included two-way analysis of variance (ANOVA) that compared 45HDT versus controls at the four experimental time points. The organ weight divided by the body weight ratio for the brain, heart, kidneys and liver in the 45HDT rats was significantly different than the control rats, regardless of time (treatment). There was no difference between the different time points (time). The average 99mTcDTPA count divided by the organ weight ratio values for the heart, liver, and spleen were significantly higher in the 45HDT group than the control group. The average counts for the heart and spleen were significantly higher at 77, 101, and 125 h than at time zero. We conclude that the major organs have different recovery patterns after 45HDT for 16 days in the rat.
Improving the Quality of Higher Education: The Scholarship of Teaching and Learning

A discussion on the importance of shifting our ideas about the nature of academic research.
Shame and guilt: characterological vs. behavioral self-blame and their relationship to fear of intimacy

The present study investigated the distinct affective experiences of shame and guilt and their relationship to self-blame (characterological vs. behavioral), blame of others, self-derogation, and fear of intimacy. As predicted, shame-proneness was associated with fear of intimacy, suggesting that shame may be an important component in intimacy fears. Moreover, shame-proneness was positively correlated with behavioral, and characterological self-blame, blame of others and self-derogation. This may indicate that shame-prone individuals are more likely to engage in self-derogating thoughts, blame their behavior and their character, as well as others, perhaps making intimacy something to be feared. In contrast, guilt-proneness was not associated with intimacy fears or blaming others for one's actions. These findings highlight the effect that shame-proneness vs. guilt-proneness can have on one's sense of self, with debilitating interpersonal consequences such as fear of intimate connections.
The Zeal of the Civil Advocate

This article is concerned with the accountability of the civil advocate for results obtained for a client. It distinguishes the criminal trial by arguing that for effective implementation the adversary system, as it is commonly understood, requires that the professional advocates be equally competent and equally adversary and that because it does not meet these criteria, the criminal trial cannot be looked to as a model either of the adversary system or of the behavior of advocates in the civil trial. Rules of behavior for the civil litigator should be drawn with the primary objective of ascertaining truth. Moreover, the civil litigator cannot claim immunity from moral accountability by reference to the lawyer's role; he or she is personally accountable for an immoral result obtained for a client. Seeking to avoid this accountability all lawyers might reject an immoral but lawful cause, so that persons with such causes would be deprived of professional representation. The conflict between the lawyer's personal morality and the social value of professional assistance is resolved by reference to a formula for assigning counsel similar to those in Mathews v. Eldridge and Lassiter v. Department of Social Services. The author analyzes the moral dilemma of a lawyer who is so assigned and proposes a solution.
Supercontinuum Generation at Mid-IR Wavelengths in Chalcogenide Photonic Crystal Fibers

Obtaining a broadband radiation spectrum in the wavelength range from 3 μm to 10 μm is a challenge. Supercontinuum generation in photonic crystal fibers appears to be a promising approach.
Continuing contamination of north Atlantic and Arctic waters by Sellafield radionuclides.

Abstract Discharges of 99 Tc and 129 I from the reprocessing plant at Sellafield have increased significantly since the mid-1990s, against the overall trend of most other radionuclides. The ‘pulsed’ release of 99 Tc has provided an opportunity to study transport pathways and transit times in UK waters, the North Sea and beyond. Transit times estimated from the 99 Tc data are significantly shorter than rates reported previously using other radiotracers. The possible reasons for this are discussed. A comparison is made between the response of seawater concentrations and those in the brown seaweed Fucus vesiculosus to variations in the release rates. Current discharges of plutonium are very low compared with the 1970s and 1980s. However, the seabed sediments of the Irish Sea represent a substantial source and remobilisation into the water column results in the continuing export of plutonium from the Irish Sea and its transport to Arctic waters.
Markov transition models for binary repeated measures with ignorable and nonignorable missing values.

Motivated by problems encountered in studying treatments for drug dependence, where repeated binary outcomes arise from monitoring biomarkers for recent drug use, this article discusses a statistical strategy using Markov transition model for analyzing incomplete binary longitudinal data. When the mechanism giving rise to missing data can be assumed to be `ignorable', standard Markov transition models can be applied to observed data to draw likelihood-based inference on transition probabilities between outcome events. Illustration of this approach is provided using binary results from urine drug screening in a clinical trial of baclofen for cocaine dependence. When longitudinal data have `nonignorable' missingness mechanisms, random-effects Markov transition models can be used to model the joint distribution of the binary data matrix and the matrix of missingness indicators. Categorizing missingness patterns into those for occasional or `intermittent' missingness and those for monotonic missingness or `mi...
Latent class analysis of substance use among adolescents presenting to urban primary care clinics

AbstractBackground: Polysubstance use during adolescence is a significant public health concern. However, few studies have investigated patterns of substance use during this developmental window within the primary care setting. Objectives: This study used an empirical method to classify adolescents into substance use groups, and examines correlates of the empirically defined groups. Methods: Data came from patients, ages 12–18 years, presenting to an urban, primary care community health clinics (Federally Qualified Health Centers) in two cities in the Midwestern United States (n = 1664). Latent class analysis (LCA) was used to identify classes of substance users. Multinomial logistic regression was used to examine variables associated with class membership. Results: LCA identified three classes: class 1 (64.5%) exhibited low probabilities of all types of substance use; class 2 (24.6%) was characterized by high probabilities of cannabis use and consequences; and class 3 (10.9%) had the highest probabilitie...
Thromboxane mediates renal hemodynamic response to infused angiotensin II

Thromboxane mediates renal hemodynamic response to infused angiotensin II. Since we had found that angiotensin II (Ang II), but not phenylephrine (PE), increased the excretion of thromboxane (Tx) and raised mean arterial pressure (MAP) by a Tx-dependent mechanism, we tested the role of TxA 2 in mediating Ang II-induced changes in renal hemodynamics. For series 1, groups of anesthetized rats received an i.v. infusion of Ang II (50 ng . kg -1 · min -1 ). When infused with a vehicle, Ang II increased MAP, renal vascular resistance (RVR) and the excretion of TxB 2 factored by GFR. A PGH 2 -TxA 2 receptor antagonist, SQ-29,548, or three days of pretreatment with a TxA 2 synthase inhibitor UK-38,485, which reduced excretion of TxB 2 by 80%, blunted the rise in MAP and RVR induced by Ang II. In contrast, three days of pretreatment with indomethacin did not alter the renal Vascular response to Ang II. For series 2, groups of rats received Ang II at a higher rate (500 ng · kg -1 · min -1 ) while the RPP was stabilized at +11 to +15 mm Hg with a suprarenal aortic clamp. SQ-29,548 and UK-38,485 both prevented Ang II-induced reductions in GFR and blocked 80% of the increase in RVR. For series 3, infusions of phenylephrine at an equipressor dose to series 2 of 30 µg · kg -1 min -1 with control of RPP at +14 mm Hg also increased RVR but this was not blunted by SQ-29,548. In conclusion: 1.) infusion of Ang II increases excretion of filtered TxB 2 , causes dose-dependent increases in RVR and, at high doses, reduces GFR. 2.) Inhibition of TxA 2 synthesis or blockade of PGH 2 -TxA 2 receptors prevents the fall in GFR and blunts 70 to 90% of the increase in RVR. 3.) These effects are independent of RPP, appear to be specific for Ang II, and are counteracted by release of vasodilator cyclooxygenase products.
Lump-sum Payments and Profit-sharing Plans in the Union Sector of the United States Economy

Lump-sum payments and profit-sharing plans became increasingly prevalent in union contracts in the U.S. economy in the 1980s. This paper analyzes the relationship between lump-sums, profit sharing, labor costs and employment, in firm-level panel data for the union sector of the U.S. economy. In general, the firm-level data suggest that profit sharing has a statistically significant effect of lowering labor cost growth. Profit sharing also appears to increase employment growth and reduce employment variability, but these results are not statistically significant. This evidence is generally consistent with hypotheses regarding the introduction of performance-related pay (Weitzman, 1984 and 1985). The effects of lump-sums, on the other hand, are not consistent with hypotheses regarding performance-related pay. Lump-sums do not appear to lower labor cost growth or increase employment growth, and increase rather than decrease employment variability. Copyright 1993 by Royal Economic Society.
Effects of phosphogypsum or calcium sulfate on aluminon reactive aluminum in solutions at varying pH

Abstract Growing evidence of positive crop responses to gypsum or phosphogypsum (PG) application in acid soils strongly support the use of these amendments as an ameliorant of subsoil acidity. Although gypsum improves Ca availability in subsoils, its role in alleviation of Al toxicity needs careful attention. In the current study, either PG, CaSO4.2H2O or CaCl2.2H2O was added (to supply 12 mM Ca) to solutions containing 40 μM Al at pH 4.1 + 0.1. Solution pH was gradually raised to 4.5, 4.8 and then to 5.3 at various time intervals during 25 d aging of the solutions at 25 + 1OC. Concentration of Al measured by aluminon method without preacidification and preheating, referred to as “reactive Al”; in this paper, was 16 μM in 2 g L‐1PG solution without added Al. This accounted 38% of total soluble Al in PG solution. Addition of 2 g L‐1PG to solution containing 40 μM Al, resulted in only 42% of total Al in solution present in forms reactive with aluminon. According to MINTEQ speciation model, Al in solution wa...
A novel in vitro model for microvasculature reveals regulation of circumferential ECM organization by curvature.

In microvascular vessels, endothelial cells are aligned longitudinally whereas several components of the extracellular matrix (ECM) are organized circumferentially. While current three-dimensional (3D) in vitro models for microvasculature have allowed the study of ECM-regulated tubulogenesis, they have limited control over topographical cues presented by the ECM and impart a barrier for the high-resolution and dynamic study of multicellular and extracellular organization. Here we exploit a 3D fibrin microfiber scaffold to develop a novel in vitro model of the microvasculature that recapitulates endothelial alignment and ECM deposition in a setting that also allows the sequential co-culture of mural cells. We show that the microfibers' nanotopography induces longitudinal adhesion and alignment of endothelial colony-forming cells (ECFCs), and that these deposit circumferentially organized ECM. We found that ECM wrapping on the microfibers is independent of ECFCs' actin and microtubule organization, but it is dependent on the curvature of the microfiber. Microfibers with smaller diameters (100–400 µm) guided circumferential ECM deposition, whereas microfibers with larger diameters (450 µm) failed to support wrapping ECM. Finally, we demonstrate that vascular smooth muscle cells attached on ECFC-seeded microfibers, depositing collagen I and elastin. Collectively, we establish a novel in vitro model for the sequential control and study of microvasculature development and reveal the unprecedented role of the endothelium in organized ECM deposition regulated by the microfiber curvature.
Management of hypertension in patients with diabetes: the place of angiotensin‐II receptor blockers

Hypertension is an important cardiovascular (CV) risk factor in patients with diabetes mellitus. In this setting, tight control of blood pressure (BP) significantly reduces CV morbidity and mortality. In the UK Prospective Diabetes Study, a 10 mmHg reduction in systolic blood pressure (SBP) was superior to a 0.7% decrease in glycosylated haemoglobin A1c (HbA1c) as far as reducing morbidity and mortality was concerned. In the Hypertension Optimal Treatment study, the risk of CV events decreased by 51% among patients with type 2 diabetes randomized to the lower BP level. Based on these findings, contemporary treatment guidelines recommend a target SBP/diastolic blood pressure of <130/ 80 mmHg for patients with diabetes.
α- versus β-hydrogen elimination in the formation of propene from an osmacyclobutane

Abstract Os(CO) 4 (CH 2 CD 2 CH 2 ) has been prepared from TsOCH 2 CD 2 CH 2 OTs and Na 2 [Os(CO) 4 ] and used to investigate the mechanism of propylene extrusion from this osmacyclobutane. Propylene is the principal product whether the thermolysis of the osmacyclobutane is carried out in solution or in a gas phase flow system. Control experiments confirm that the osmacyclobutane does not rearrange prior to thermal decomposition, and that no secondary reactions affect the position of the deuterium labels in the propylene after it is formed in the gas phase. Both CH 3 CDCHD and CH 2 DCDCH 2 are formed, indicating that both α- and β-hydrogen elimination mechanisms are operative. The insertion of CO into the osmacyclobutane ring is facile and may be a step in the propylene extrusion mechanism.
The hardness, stiffness and toughness of diphasic abrasive materials prepared by sol-gel techniques

Sol-gel techniques have been used to make single-phase alumina and diphasic Ni, NiO and NiAl2O4-alumina and AgCl-silica abrasive grains. The hardness, stiffness and toughness of these grains have been measured by indentation methods. The results have been compared with the results of similar measurements on soda-lime glass and on such current generation abrasives as α-Al2O3, α-SiO2, Cubitron® and Norzon®. The new composite NiAl2O4-alumina grain has properties that compare well with those of current abrasives.
Comparison of methods for solving nonlinear finite-element equations in heat transfer

Abstract We have developed two new methods for solving the finite-element heat-transfer equations with highly nonlinear boundary conditions and material properties. When compared with the more commonly employed successive substitution and Newton-Raphson procedures, the new methods speed convergence rates, increase the radius of convergence, or reduce user interaction. The first method accelerates the standard Newton-Raphson technique when the degree of the nonlinearity is known (for example, radiation boundary conditions or a prescribed temperature dependence in the thermal conductivity). The accelerated Newton-Raphson can reduce the computational time by more than 80% when compared with the standard Newton-Raphson technique. The second method employs feedback to regulate the solution algorithm during execution. Comparisons of these methods are given for several practical examples.
Phylogeny of Lymphocyte Structure and Function

Data from mammalian systems on the molecular basis of immune recognition, on the structural and functional heterogeneity of lymphocytes, and on the interactions between lymphocytes have provided guidelines for examining the lymphocyte from a phylogenetic perspective. Current information indicates that regardless of the variability of organized lymphoid tissues and the sometimes subtle diversity of immune responses in evolutionarily distant forms, the small lymphocyte has been maintained both morphologically and as an effector of immune reactivities throughout vertebrate phylogeny. Moreover, the basic properties of the mammalian lymphocytes—the discriminatory recognition of nonself plus the amplification steps that follow such a recognition event appear to be common to lymphocytes from all vertebrates. Although examples of lymphocyte heterogeneity and cellular cooperation have been reported for representative elasmobranchs, teleosts, and amphibians, the extent and nature of lymphocyte diversity remain as major unsolved problems currently being investigated by immunologists.
Blood levels of diazepam after endotracheal administration in dogs.

A pilot study was performed to evaluate the endotracheal administration of diazepam. Five mongrel dogs were anesthetized and orotracheally intubated. Diazepam in a dose of 0.5 mg/kg was delivered through a red rubber catheter placed through the endotracheal tube. Diazepam levels were then measured at 0, 30, and 60 seconds, and at 2, 5, 15, 30, and 60 minutes. Arterial blood gas determinations were performed at 0, 10, 30, 60, and 90 minutes. In all dogs peak serum levels averaged 1,500 ng/ml ± 541 ng/ml, which is well above therapeutic anticonvulsant levels (150 ng/ml to 600 ng/ml). Arterial pH and PCO 2 did not change dramatically from control values during the period of study. Arterial PO 2 showed a transient drop of approximately 10 to 30 mm Hg within the first 60 minutes, but returned nearer the control values by the end of 90 minutes. The endotracheal administration of diazepam has been shown to be effective in achieving rapid therapeutic serum levels of the drug. Further study is needed to determine any deleterious effects on the lungs before this method of administration can be recommended for use in humans.
A review of self modeling and related interventions.

Abstract About 150 studies exist in print, examining the use of self modeling (mostly in the video medium) in a variety of training and therapeutic applications. Evidently, two lines of thoughts have driven the development of these applications: (a) an extension of peer modeling or (b) a description of personal success. Studies report self-modeling interventions for physical skills (rehabilitation, sports), academic and vocational issues, communication, and personal and social adjustment. A wide range of ages (toddler to grandparent) and diverse developmental conditions have been addressed. The most fruitful applications may be those that emphasize the image of future success —skills not previously attained and adaptive responses to a challenging context. Rather than examine efficacy related to target “problems,” this review identifies categories of application made possible by current knowledge and technology (e.g., use of hidden supports, selectively editing low-frequency behaviors). Seven such categories are identified and illustrated with descriptions of interventions. The evidence is used to argue for the recognition of learning from the observation of one's own successful or adaptive behavior (or images of it) as a mechanism in its own right.
Dynamics of oscillating drops with thermocapillary effects

The dynamics of oscillating drops warming up in a hot gas environment is investigated via numerical simulation. The formation of surface and internal flows, due to variation of surface tension with temperature, and their impact on the oscillations are discussed. Both surface and ambient temperature disturbances are considered in terms of spherical harmonics. The effects of various parameters including modes of surface and temperature disturbances on period and amplitude of oscillations, kinetic and surface energies, and temperature field are studied. The most obvious feature of thermocapillary flows is demonstrated by vortices whose number and strength varies with the mode of temperature disturbance. These vortices tend to modify the amplitude of oscillations and enhance the kinetic energy. It is also shown that the decrease of the surface tension with increasing temperatures results in the increase of the period of oscillations while decreasing the surface energy. Due to the presence of thermocapillary flows, at long times, the equilibrium shape of the drop is not spherical and the kinetic energy approaches nonzero asymptotic values. The average temperature shows a nearly linear increase in time while the root mean square temperature, used to indicate the spatial variation, levels off after a fast initial growth.
Resolution of initially excited and relaxed states of tryptophan fluorescence by differential-wavelength deconvolution of time-resolved fluorescence decays.

Abstract We describe a new procedure for the analysis of time-resolved decays of fluorescence intensity. This procedure was used to resolve the emission spectra of the initially excited and solvent relaxed states of a tryptophan derivative in viscous solution. Specifically, we examined N -acetyl- l -tryptophanamide (AcTrpNH 2 ) in viscous and nonviscous solutions of propylene glycol. Time-resolved decays of fluorescence intensity were collected at wavelengths across the emission spectra. Instead of the usual procedure of deconvolving these data with the time profile of the exciting pulse, we deconvolved these data using the response observed on the short-wavelength side of the emission. If one assumes that this emission results only from the initially excited state (F), then the nonzero decay time calculated using deconvolution is that of the solvent relaxed state (R). For our specific case of AcTrpNH 2 the emission spectra of the F and R states overlap at most wavelengths longer than the short-wavelength side of the emission (310 nm). As a result, differential-wavelength deconvolution yields two lifetimes and amplitudes, one pair representing the relaxed state and the other the initially excited state. The latter appears as a zero-decay-time component whose amplitude can be readily quantified. The wavelength-dependent amplitude of this zero-lifetime component can be used to calculate the emission spectrum of the F state and. by difference, the emission spectrum of the relaxed state. For AcTrpNH 2 in propylene glycol at −20°C the emission maxima of the F and R states are near 320 and 350 nm, respectively, and the relative proportion of the emission from each state was near 50%. At lower temperatures the emission from the F state becomes dominant and at high temperatures the emission from the R state dominates. We note that this resolution of states is somewhat arbitrary because we assumed a two-state model and the absence of solvent relaxed emission at 310 nm. Nonetheless, differential-wavelength deconvolution simplifies and facilitates the analysis of time-resolved fluorescence data from samples which undergo excited state reactions. Moreover, this deconvolution procedure considerably simplifies the determination of the kinetic constants for reversible excited state reactions. The application of differential-wavelength deconvolution does not increase the time reqaired for data acquisition. This differential analysis procedure should enhance the usefulness and precision of pulse fluorometric methods in studies of nanosecond time scale processes in proteins and membranes.
Circadian Rhythms: Variation in Sensitivity of Isolated Rat Atria to Acetylcholine

Experiments were performed at two time points in the 24hour cycle to determine whether isolated right atria of rats would vary in sensitivity, with a circadian rhythm, to two concentrations of acetylcholine. The beating rate of the atria decreased more in response to the drug if the atria were isolated at 1100 than if isolated at 2300 hours.
Preliminary results using ultrasound transmission for image-guided thermal therapy.

Abstract The feasibility of using an acoustic camera as a real-time imaging device for thermal surgery was investigated. The study compares camera images of tissue samples taken before, during and after a volume of tissue was thermally coagulated using focused ultrasound (US). This apparatus has analogous acoustic counterparts to an optical charge couple device (CCD) camera. The setup was operated in transmission mode, with a tissue sample placed between the camera and a 10-MHz illuminating transducer. A high-intensity continuous-wave US signal from a therapeutic transducer was focused inside the sample tissue. A reversible, time-dependent variation in image intensity was observed in the region of the therapeutic sonications in all tissues tested: bovine fat and porcine and rabbit livers. Correlations between image intensities and temperatures were shown; rabbit liver resulted in a correlation coefficient (R 2 ) of 0.6694 and bovine fat resulted in an R 2 of 0.9455. When temperatures high enough to coagulate tissue were reached, permanent changes in the images were observed. Lesion locations and dimensions from the images were found to be comparable to the sectioned tissue samples. An R 2 of 0.919 resulted when lesion size detected from the camera was compared to the actual lesion size. Preliminary results may indicate that the camera has an application for monitoring thermal surgery. (E-mail: rlking@bwh.harvard.edu)
Probabilistic analysis of strong hypergraph coloring algorithms and the strong chromatic number

Abstract We present coloring algorithms for several strong coloring problems and analyze their performance in spaces of random hypergraphs. In these spaces the number of colors used by our algorithms is almost surely within a small constant factor (less than 4) of the strong chromatic number of the hypergraph.
In vitro induction of E-rosette formation in human bone marrow cells by the thymic proteins LSHr and LSHh.

Abstract Two thymic factors, LSHh and LSHr, were found to be active in the induction of E-rosette formation. In vitro incubation of human bone marrow cells, isolated by Ficoll gradient centrifugation, with subnanogram quantities of either of these LSH proteins increased the number of E-rosette-forming cells in the bone marrow cultures by a factor of two. Kidney extract and bovine serum albumin did not show significant activity when tested as controls. Commercial thymopoietin II peptide was found to be active in this assay at comparable concentrations. The data allow a comparison of LSH proteins with other preparations tested in this manner.
Overview of emergency radiological management of the pregnant patient, especially the traumatized pregnant patient

Both traumatic and nontraumatic acute emergencies are seen in hospitals in women of childbearing age. The effects of radiation are theoretically most deleterious from 10 days after conception until roughly the end of the first trimester. However, there should be no hesitation about performing appropriate emergency imaging studies at any time during pregnancy. If time permits, the presence and age of the fetus should be determined through physical examination, appropriate laboratory studies, and the obtaining of adequate medical historical information. Imaging studies can be roughly classified into two main categories, those with minimal radiation effect and those that may expose the fetus to significant potential ionizing energy. The radiologist must be responsible for the determination of the most appropriate studies needed and in what sequence. Traumatized pregnant patients especially require maternal and fetal monitoring prior to arrival at the hospital and throughout the hospital stay. Fetal demise is a significant risk in case of both minor and major trauma. Maternal survival is the most significant factor in fetal well-being, with a fetal death approaching 80 % in cases of maternal shock and almost 100 % where there is partial or complete abruptio placentae. Properly performed imaging of the pregnant female, where the uterus is not likely to be exposed to ionizing radiation, should be cause little concern. Depending on the clinical presentation, appropriate first images might include a cervical spine, a portable chest film, an abdominal film, and a lateral decubitus view to check for suspected bowel perforation. This should be rapidly followed by fetal and then maternal ultrasonography. Overall, CT may be the best single abdominal study for severe abdominal problems where multiple organ damage is suspected. MRI for neurological disease and carefully monitored of selective vascular embolization for life-threatening abdominal bleeding are other important legitimate imaging studies.
Early regional variations in motoneuron numbers arise by differential proliferation in the chick embryo spinal cord

Regional differences in the number of motoneurons in the spinal cord of the chick are thought to arise developmentally by region-specific cell death and cell migration. In this way, a numerically homogeneous motor column throughout the spinal cord is believed to be molded into the adult pattern. Region-specific differences in proliferation are not thought to play a significant role in this process. By counting motoneurons in serial sections throughout the rostral-caudal extent of the spinal cord on Embryonic Day 4 in the chick, we have found that the numerical variations in motoneurons in different spinal cord regions are already foreshadowed by this stage, which is before the onset of both cell death and the secondary migration of neurons out of the motor column. These results indicate that although nonproliferative events may contribute to the later regional variations in motoneuron numbers, the initial differences themselves are created early on by regionally specific proliferative events.
The Lake Michigan meteotsunamis of 1954 revisited

Two large meteotsunami wave events on Lake Michigan impacted the Chicago coastline within 10 days of each other in 1954. Initial data analysis suggested that the fatal first event (June 26) was caused by a Proudman resonant non-trapped wave, while the second event (July 6) was caused by Greenspan resonant trapped edge waves. In this study, a numerical hydrodynamic model was used to reveal the detailed behavior of these events. For both events, the atmospheric pressure and wind perturbations were found to be essential to explain the magnitude of the wave activity, in contrast to the initial conclusions that the waves were primarily pressure-driven. In the June 26 meteotsunami, Proudman resonance wave was the primary cause of the destructive wave, though the storm also generated edge waves which persisted for many hours, hindering rescue efforts. The maximum wave heights for the July 6 event were found to be the product of a superposition of edge waves and non-trapped waves rather than purely edge waves as originally thought. The results from these events demonstrate the enclosed Lake Michigan basin retained and focused wave energy, leading to their large magnitude, long duration, and destructive nature.
Power sums over subspaces of finite fields

Abstract Let K be the finite field of order q m + 1 , which is regarded as an ( m + 1 ) -dimensional vector space over F q . For each h-dimensional F q -subspace V of K, α ∈ K and 0 ⩽ t ⩽ q m + 1 − 1 , we define S t ( V , α ) = ∑ v ∈ V ( α + v ) t . For each 1 ⩽ h ⩽ m , we obtain sufficient conditions on t for the vanishing of S t ( V , α ) ; when h = m , combining this result with some p-rank results from coding theory, we obtain necessary and sufficient conditions on t for the vanishing of S t ( V , α ) .
Lysis of Escherichia coli with a neutral detergent

1. When Escherichia coli cells are treated with lysozyme and versene for 30–45 sec in an ice-bath, they become susceptible to lysis by the neutral detergent Brij-58. 2. The rate of lysis is dependent upon the concentration of the detergent. Brij-58 is approx. 1000-fold less active in lysis of the lysozyme-versene-treated cells than is deoxycholic acid or sodium docecylsulphate. 3. The extent of cell disruption is dependent upon the Mg^(2+) concentration and the ionic strength at the time of lysis. In 70 mM Mg^(2+), only the low molecular weight soluble RNA and soluble protein are released from the cell. In 40 mM Mg^(2+), the 70-S monosomes and the ribosome subunits are released together with the soluble material. At still lower Mg^(2+) concentrations, the polyribosomes are released. 4. Unless the Mg^(2+) concentration is reduced below 5 mM, the cellular DNA, after lysis, may be almost completely sedimented by centrifugation at 3000 × g for 5 min. 5. All strains of E. coli tested were susceptible to lysis by this method.
Issues facing organizations when implementing formal mentoring programmes

Formal mentoring programmes are a recent innovation in organizations. Describes interviews with managers of five organizations who were involved in the development and implementation of their company’s mentoring programme. Provides examples of the types of issues that arose and how they were resolved.