cssi/SciSciGPT-SciSciNet huggingface dataset:
Update on current models of HIV-related neuronal injury: platelet-activating factor, arachidonic acid and nitric oxide

This review aims to summarize recent work related to the pathogenesis and possible treatment of neuronal injury in the acquired immunodeficiency syndrome (AIDS), especially with reference to potential neurotoxic substances released by HIV-infected or gp120-stimulated macrophages/microglia. Approximately a third of adults and half of children with AIDS eventually suffer from neurological manifestations, including dysfunction of cognition, movement, and sensation. Among the various pathologies reported in brains of patients with AIDS is neuronal injury and loss. A paradox arises, however, because neurons themselves are for all intents and purposes not infected by human immunodeficiency virus type 1 (HIV-1). This paper reviews recent evidence suggesting that at least part of the neuronal injury observed in the brains of AIDS patients is related to excessive influx of Ca2+ after the release of potentially noxious substances from HIV-infected or gp120-stimulated macrophages/microglia. There is growing support for the existence of HIV- or immune-related toxins that lead indirectly to the injury or demise of neurons via a potentially complex web of interactions between macrophages (or microglia), astrocytes, and neurons. HIV-infected monocytoid cells (macrophages, microglia or monocytes), especially after interacting with astrocytes, secrete substances that potentially contribute to neurotoxicity. Not all of these substances are yet known, but they may include eicosanoids, i.e. arachidonic acid and its metabolites, as well as platelet-activating factor. Other candidate toxins include nitric oxide (NO.), superoxide anion (O2.-), and the N-methyl-D-aspartate (NMDA) agonist, cysteine. Similarly, macrophages activated by HIV-1 envelope protein gp120 also appear to release arachidonic acid and its metabolites, and cysteine.(ABSTRACT TRUNCATED AT 250 WORDS)
Nonparametric Hard Limiting and Sign Detection of Narrow-Band Deterministic and Random Signals

Hard limiting or sign detection schemes for low-pass known and random signals in additive noise are popular as very simple signal detectors maintaining constant values for their false-alarm probabilities under the rather weak assumption that the sampled noise observations have zero median values. For nonparametric detection of narrow-band signals the natural extension of the zero medians assumption is the zero marginal medians assumption on the in-phase and quadrature noise components. Nonparametric detectors operating under this assumption are developed here for narrow-baud signals; these can be taken to be the logical counterparts of the low-pass sign correlator and polarity coincidence correlator detectors of low-pass theory. The concept of conditional testing, which has been applied previously to obtain efficient multilevel versions of low-pass sign detection schemes, is shown to enter quite naturally in the definition of narrow-band counterparts of the sign correlator and the polarity coincidence correlator detectors. It is also shown that under the diagonal symmetry extension of the low-pass univariate symmetry condition on the noise probability density function, multilevel extensions of these conditional test narrow-hand detectors may also be defined as counterparts of the multilevel conditional test schemes for low-pass signals.
Yeast tRNAPhe expressed in human cells can be selected by HIV-1 for use as a reverse transcription primer

All naturally occurring human immune deficiency viruses (HIV-1) select and use tRNA(Lys,3) as the primer for reverse transcription. Studies to elucidate the mechanism of tRNA selection from the intracellular milieu have been hampered due to the difficulties in manipulating the endogenous levels of tRNA(Lys,3). We have previously described a mutant HIV-1 with a primer binding site (PBS) complementary to yeast tRNA(Phe) (psHIV-Phe) that relies on transfection of yeast tRNA(Phe) for infectivity. To more accurately recapitulate the selection process, a cDNA was designed for the intracellular expression of the yeast tRNA(Phe). Increasing amounts of the plasmid encoding tRNA(Phe) resulted in a corresponding increase in levels of yeast tRNA(Phe) in the cell. The yeast tRNA(Phe) isolated from cells transfected with the cDNA for yeast tRNA(Phe), or in the cell lines expressing yeast tRNA(Phe), were aminoacylated, indicating that the expressed yeast tRNA(Phe) was incorporated into tRNA biogenesis pathways and translation. Increasing the cytoplasmic levels of tRNA(Phe) resulted in increased encapsidation of tRNA(Phe) in viruses with a PBS complementary to tRNA(Phe) (psHIV-Phe) or tRNA(Lys,3) (wild-type HIV-1). Production of infectious psHIV-Phe was dependent on the amount of cotransfected tRNA(Phe) cDNA. Increasing amounts of plasmids encoding yeast tRNA(Phe) produced an increase of infectious psHIV-Phe that plateaued at a level lower than that from the transfection of the wild-type genome, which uses tRNA(Lys,3) as the primer for reverse transcription. Cell lines were generated that expressed yeast tRNA(Phe) at levels approximately 0.1% of that for tRNA(Lys,3). Even with this reduced level of yeast tRNA(Phe), the cell lines complemented psHIV-Phe over background levels. The results of these studies demonstrate that intracellular levels of primer tRNA can have a direct effect on HIV-1 infectivity and further support the role for PBS-tRNA complementarity in the primer selection process.
Conditions of Caregiving, Provider Nurturance and Quality Care

Participants included 36 licensed family day care providers from six rural counties who had been providing care for a mean of 8.3 years (SO = 6.8 years). Fourteen of the providers had earned high school diplomas; twenty‐two had some post high school education. At least one child from an economically strained home (as measured by AFDC receipt) was present in 44.4% of the FDC homes. Dependent measures included: The Caregiver Interaction Scale (Arnett, 1989); Elaboration Scale from The Family Day Care Rating Scale (FDCRS, Harms and Clifford, 1989); FDCRS Total Score; and FDC program structure (e.g. frequency of enrichment activities, Kontos and Riessen, 1993). Professional self‐perceptions and perceptions of job significance were assessed by self‐report (adapted from Whitebook, Howes and Phillips, 1990). Provider nurturance was influenced by the presence of children from economically strained homes and by provider education levels. Positive provider self‐perceptions negatively influenced program structure. W...
980 CYTOMEGALOVIRUS (CMV) SPECIFIC CYTOTOXIC CELL-MEDIATED IMMUNITY (CMI) DURING PREGNANCY

Maternal cytotoxic CMI functions may modify vertical CMV transmission51 and/or disease manifestations but are ill defined. We performed Cr release cytotoxicity assays for CMV specific natural killer (NK), antibody dependent cell-mediated cy to toxicity (ADCC), and MHC-restricted CMV specific cytotoxic (MRCC) activities in uninfected and CMV infected inbred strain 2 guinea pigs during pregnancy. Animals were infected with 105 TCID50 tissue culture attenuated CMV during the first trimester (median gestation day 27). CMV infected nonpregnant controls had augmented NK activity at two weeks (49.2 ± 11.7%) returning to baseline (22.9 ± 2.3) at 8 weeks, and had peak MRCC at six weeks (14.4 ± 5.5%). In contrast, NK augmentation in CMV infected pregnant (CIP) was delayed until two weeks postpartem (37.0 ± 2.5%). Uninfected pregnant (UP) animals had depressed NK activity during the second trimester, third trimester and two weeks postpartem (11.1 ± 1.5, 7.0 ± 1.1 and 9.9 ± 3.1%) compared to CIP (24.5 ± 7.2, 23.6 ± 7.1 and 27.9 ± 5.3%) (P < .05) and uninfected nonpregnant animals (UNP) (20.9 ± 4.8) (P <.05). Neither UNP nor UP animals expressed CMV specific MRCC or ADCC. CIP acquired CMV specific MRCC (11.0 ± 2.3, 4.0 ± 1.5, and 10.9 ± 2.3%). ADCC was not detected in plasma of CIP animals until two weeks postpartem (10.3 ± 4.2%). Infection, pregnancy, and infection during pregnancy alter CMI to CMV. This model should allow investigation of the roles of each CMI function in the pathogenesis of congenital CMV infection.
Lattice expansion of LSCF-6428 cathodes measured by in situ XRD during SOFC operation

Abstract A new capability has been developed for analyzing solid oxide fuel cells (SOFCs). This paper describes the initial results of in situ X-ray diffraction (XRD) of the cathode on an operating anode-supported solid oxide fuel cell. It has been demonstrated that XRD measurements of the cathode can be performed simultaneously with electrochemical measurements of cell performance or electrochemical impedance spectroscopy (EIS). While improvements to the technique are still to be made, the XRD pattern of a lanthanum strontium cobalt ferrite (LSCF) cathode with the composition La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3− δ (LSCF-6428) was found to continually but gradually change over the course of more than 60 h of operation in air under typical SOFC operating conditions. It was determined that the most significant change was a gradual increase in the cubic lattice parameters of the LSCF from 3.92502 A (as determined from the integration of the first 20 h of XRD patterns) to 3.92650 A (from the integration of the last 20 h). This analysis also revealed that there were several peaks from unidentified minor phases that increased in intensity over this timeframe. After a temporary loss of airflow early in the test, the cell generated between 225 and 250 mW cm −2 for the remainder of the test. A large low frequency arc in the impedance spectra suggests the cell performance was gas diffusion limited and that there is room for improvement in air delivery to the cell.
In vitro comparison of embryonic myoblasts and myogenic cells isolated from regenerating adult rat skeletal muscle.

Abstract Myogenic cells from regenerating adult rat muscle were compared in culture with embryonic myoblasts. No differences were found in their growth rates or fusion characteristics. Embryonic and regenerating cells fused with one another to form mosaic myotubes. Both showed the same increase in creatine kinase activity and shift in isozyme profile following fusion. These results support the view that myogenic cells from regenerating muscle are essentially the same as embryonic myoblasts.
Enthalpy of combustion of acetylsalicylic acid

Abstract The massic energy of combustion of crystalline acetylsalicylic acid was determined in an NIST adiabatic-aneroid-rotation bomb calorimeter. The standard molar enthalpy of combustion at T = 298.15 K and po = 105Pa is ΔcHmo(C9H8O4, cr, 298.15K) = − (3926.71 ± 0.34)kJ · mol − 1. The derived standard molar enthalpy of formation is ΔfHmo(C9H8O4, cr, 298.15K) = − (758.19 ± 0.52)kJ · mol − 1. The molar enthalpy of fusion ΔfusHmo(C9H8O4, cr, 414.0K) = (29.80 ± 0.22)kJ · mol − 1was determined by differential scanning calorimetry. The molar Kirchhoff relationship, d(ΔH) = ΔCpdT, was used to convert this value to T = 298.15 K, ΔfusHmo(C9H8O4, cr, 298.15K) = (19.28 ± 0.22)kJ · mol − 1. The molar enthalpy of vaporization was estimated using the group contribution scheme of Lebedev and Miroshnichenko. The molar enthalpy of vaporization of acetylsalicyclic acid was estimated as ΔvapHmo(C9H8O4, cr, 298.15K) = (106.4 ± 2.0)kJ · mol − 1. The molar enthalpies of fusion and vaporization were used to calculate enthalpies of formation for the liquid and gaseous states of acetylsalicyclic acid, ΔfHmo(C9H8O4, l, 298.15K) = − (738.91 ± 0.56)kJ · mol − 1and ΔfHmo(C9H8O4, g,298.15K) = − (632.5 ± 2.1)kJ · mol − 1, respectively.
Commentary: Teaching Technical Writing in a Collaborative Computer Classroom

Twenty years ago I had no idea what a computer was. Ten years ago I knew what computers were, but I had never sat at a terminal. I just assumed that computers were machines used in those «other»disciplines, certainly not in English courses. Today, I teach my technical writing classes in a collaborative computer classroom. The classroom consists of twelve networked computers which my twenty-four students per class use in tandem. Despite my original ignorance of computers, I'm now happily ensconced in a computer classroom. In fact, computers are so important, I've concluded, that teaching writing without the aid of computers does our students a disservice. How did I make such a complete turn-around in attitude?
Most Caenorhabditis elegans microRNAs Are Individually Not Essential for Development or Viability

MicroRNAs (miRNAs), a large class of short noncoding RNAs found in many plants and animals, often act to post-transcriptionally inhibit gene expression. We report the generation of deletion mutations in 87 miRNA genes in Caenorhabditis elegans, expanding the number of mutated miRNA genes to 95, or 83% of known C. elegans miRNAs. We find that the majority of miRNAs are not essential for the viability or development of C. elegans, and mutations in most miRNA genes do not result in grossly abnormal phenotypes. These observations are consistent with the hypothesis that there is significant functional redundancy among miRNAs or among gene pathways regulated by miRNAs. This study represents the first comprehensive genetic analysis of miRNA function in any organism and provides a unique, permanent resource for the systematic study of miRNAs.
Significance of delay in the performance of monkeys with medial temporal lobe resections.

Five studies using 37 Rhesus monkeys were carried out to determine the significance of the length of delay interval in reported performance deficits following temporal rhinencephalic lesions. In five experiments monkeys were trained and tested on delayed alternation (DA) and delayed response (DR) at both conventional and long delay intervals, and at long delay intervals on delayed successive discrimination (DSD).
Attachment of Vibrio cholerae under various environmental conditions and to selected substrates

Attachment rates of Vibrio cholerae (three tox+ strains of serotype 01 and two non-01's) were examined using epifluorescent microscopy and TEM. The effects of temperature, pH, various ions and nutrient starvation on attachment were determined. Optimum attachment occurred at 35°C, pH 2, concentrations of 1.0–1.5% NaCl, 1.0–1.5% KCl, 0.5–0.1% MgCl2 (with 1.0% NaCl), and 1.0–0.5% CaCl2 (with 1.0% NaCl). After one day of starvation, attachment declined by 75% with little change during further starvation. Adhesion to a variety of non-living substrates, more than 25 species of algae, and three species of aquatic plants was examined using direct fluorescent staining, fluorescent monoclonal antibody and epifluorescent microscopy. Attachment was expressed numerically as an adhesion index. The highest rate of attachment to natural substrates occurred with (some forms of) chitin and diatomaceous earth. Highest rates on algae were noted on three species of green algae, one species of red and one species of yellow green. Since V. cholerae can readily attach to many substrates common in tropic and semi-tropical estuarine waters and under conditions typical of estuarine and marine waters, this is consistent with the hypothesis that the estuarine environment is an ideal reservoir for cholera-causing strains of V. cholerae.
Precaution for using nucleic acid-based methods to detect Aeromonas.

Aeromonas is ubiquitous in aquatic ecosystems but can cause various human infections, including gastrointestinal tract syndromes and soft tissue infections ([3][1]). Its role as a diarrheal agent remains controversial, but several studies show a substantial association ([1][2], [2][3], [4][4], [6][5
Structures associated with feeding in three broad-mouthed, benthic fish groups

The flatheads, toadfishes, and goosefishes discussed here hold certain features in common. All are bottom-living forms with depressed head areas and broad gapes, and all eat large food items: fishes and/or crabs. All have developed structural specializations in association with this diet. The three groups are at most distantly related, and their feeding specializations are different and have evolved from different bases. In flatheads the combination of large food items and depressed head regions seems to have led to the separation of the two halves of the pelvic girdle, a feature in which they differ from their scorpaenoid relatives. Toadfish peculiarities associated with feeding are various but most notable in those that pass crabs they eat through the gape and into the mouth. Goosefish feeding is centered around the use of a lure to attract prey to within striking distance. The three fish groups are discussed separately, but their feeding structures are compared to one another in the final section of the paper.
Two photon laser photo-ionisation of molecules in liquids

Abstract Electrons are produced in several organic liquids by the two-photon laser photolysis of dissolved anthracene and pyrene. The rate constants for reaction of the electrons with biphenyl and O 2 are measured, and are in agreement with the known mobilities of the electrons in these liquids.
Towards the intrinsic error of the correlation consistent Composite Approach (ccCA)

The correlation consistent Composite Approach (ccCA) has been made more robust by (a) modifying the basis set used in computing B3LYP equilibrium geometries and harmonic vibrational frequencies so that the correlation consistent basis sets are used throughout ccCA; (b) separately extrapolating the MP2 and Hartree–Fock complete basis set limit energies; (c) uniformly treating unrestricted open shell wave functions; (d) utilizing newly recommended enthalpies of formation for C, B, Al, and Si atoms; and (e) using theoretically derived vibrational scale factors. This modified ccCA formulation has been used to compute the 454 energetic properties (enthalpies of formation, dissociation energies, ionization potentials, electron affinities, and proton affinities) in the G3/05 test set. This new formulation, which does not contain any optimized parameters, has a small systematic statistical bias (mean signed deviation of −0.20 kcal mol−1), and has a mean absolute deviation of 1.01 kcal mol−1 with the incorporation...
Group cinematherapy: Using metaphor to enhance adolescent self-esteem

Abstract This study examines the effectiveness of a cinematherapy intervention at enhancing the perceived self-esteem of 16 youth with a serious emotional disturbance. Participants completed the Rosenberg Self-Esteem Scale (RSE) at pre-, post-, and 1-week follow-up within a 6-week coping skills group in which a brief cinematherapy intervention is introduced to a treatment and delayed treatment group. A control group was used, which only received the coping skills training. Results of a split-plot analysis of variance (ANOVA) with one between-groups factor and one repeated-measures factor revealed no significant differences within or between groups, however, meaningful differences between the three groups were found. Implications for counselors and therapists are discussed.
Ulnar Lengthening and Radial Recession Procedures for Kienböck’s Disease Long-term clinical and radiographic follow-up

Twenty patients with Kienbock's disease who had undergone a joint levelling procedure, were reviewed at a mean of 11 years following surgery. Clinical and radiological evaluation revealed good long-term results with all patients complaining of less pain than before surgery and with statistically significant increases in range of motion and grip strength. Radiologically a significant number of patients were found still to have lunate fractures and fragmentation. In addition, 13 patients have developed new bone formation in the lunate fossa, and 12 show osteoarthritic changes, particularly at the radioscaphoid interface. Radial shortening was felt to be superior to ulnar lengthening in that there were fewer problems with bone union.
Lipids of frog retinal pigment epithelium: Comparison with rod outer segments, retina, plasma and red blood cells

The glycerolipid and fatty acid compositions of frog retinal pigment epithelium (RPE) were determined and compared with rod outer segments (ROS), retina, plasma, and red blood cells (RBC). The glycerolipid class composition of RPE was similar to RBC and ROS or retina, with phosphatidylcholine and phosphatidylethanolamine being the major components. The fatty acid composition of RPE differed substantially from that of plasma or RBC; the former contained much higher levels of C-20 and C-22 polyunsaturated fatty acids (PUFAs), such as 20:4n-6 and 22:6n-3, but less C-18 mono-, dienoic, and trienoic acids. The difference between RPE and ROS or retina with respect to fatty acid profile was also dramatic; RPE had relatively less 22:6n-3, but more 20:4n-6 and 18:2n-6, than ROS or retina. These results suggest that frog RPE cells may selectively take up C-20 and C-22 PUFAs from the circulation, but preferentially deliver 22:6n-3 to the ROS and retina. Fatty acid analyses show that 20:4n-6 and 22:6n-3 were unevenly distributed among RPE glycerolipids; phosphatidic acid, diglyceride, triglyceride, and phosphatidylserine are relatively more enriched in 22:6n-3 compared with 20:4n-6. This information might imply that these two PUFAs are metabolized differently inside the frog RPE cells.
Thermodynamic metrics for aggregation of natural resources in life cycle analysis: insight via application to some transportation fuels.

While methods for aggregating emissions are widely used and standardized in life cycle assessment (LCA), there is little agreement about methods for aggregating natural resources for obtaining interpretable metrics. Thermodynamic methods have been suggested including energy, exergy, and emergy analyses. This work provides insight into the nature of thermodynamic aggregation, including assumptions about substitutability between resources and loss of detailed information about the data being combined. Methods considered include calorific value or energy, industrial cumulative exergy consumption (ICEC) and its variations, and ecological cumulative exergy consumption (ECEC) or emergy. A hierarchy of metrics is proposed that spans the range from detailed data to aggregate metrics. At the fine scale, detailed data can help identify resources to whose depletion the selected product is most vulnerable. At the coarse scale, new insight is provided about thermodynamic aggregation methods. Among these, energy analys...
Corporate Strategy in the Tobacco Manufacturing Industry: The Case of Philip Morris

The purpose of this case study is to identify corporate strategy options at Philip Morris in an uncertain business and legal environment. Because it controls approximately one-half of the domestic market for tobacco products, efforts by antismoking advocates directed toward getting Philip Morris to change its corporate policies are a major step toward getting policy changes accomplished within the entire tobacco manufacturing industry. The company has been the largest player in a structurally oligopolistic industry with only a small number of important competitors. In October 1999, on a web site position paper, Philip Morris admitted that smoking is a contributing factor to the development of a variety of diseases and that cigarette smoking was addictive. The paper examines legal issues pertaining to lawsuits directed toward claims on behalf of smokers and their families. A jury verdict in the Florida class action lawsuit on behalf of smokers, now under appeal, would require payments approximately equal to the entire market capitalization of Philip Morris on the day the verdict was announced. The paper outlines three possible organizational strategies in the face of continuing legal issues which threaten the future of the company: (1) Continue as they are now operating as a single company; (2) Spin off nontobacco components to shareholders as a separate company; and (3) Discontinue domestic manufacture and sale of tobacco products while maintaining an international tobacco business.
Hydrodynamics of bolus flow—An analytical approach to blood flow in capillaries

A model which was used by Prothero and Burton to simulate a particular configuration in capillary blood vessels is investigated from a hydrodynamic point of view. In this model, the erythrocytes are approximated by rigid pistons, and plasma is assumed to be an incompressible Newtonian fluid. An order of magnitude analysis using the physiologically realistic values for various parameters reduces the exact equations of motion to an equation describing the creeping motion of the fluid. An analytical approach to the solution of the equation is proposed and some results are reported here. The solution of the flow field is given in terms of a stream function which is represented by two infinite series composed of known functions. Two coupled infinite systems of algebraic equations determining the coefficients of the two series have been derived. This method of solution is proposed as an alternative to the entirely numerical procedure of solving the similar problem proposed by Bugliarelloet al. A limiting case of large aspect ratio (the ratio of the axial spacing of the two successive erythrocytes to the capillary diameter) is studied and the solution, valid away from the erythrocyte surface, has been obtained in simple form. It resembles the classical Poisenille flow, but the pressure gradient is related to the erythrocyte speed.
The cerebral basis of lateral asymmetries in attention

Abstract Asymmetries in the processing of input to either side of the midline are related to hemispheric specialization in man. These asymmetries arise when preponderant activation of one hemisphere biases attention to the contralateral side. This unbalanced cerebral activation is a function of the nature of the subject's task or expectancy. A model of hemispheric integration is proposed.
Estimates of auditory risk from outdoor impulse noise II: Civilian firearms

Firearm impulses are common noise exposures in the United States. This study records, describes and analyzes impulses produced outdoors by civilian firearms with respect to the amount of auditory risk they pose to the unprotected listener under various listening conditions. Risk estimates were obtained using three contemporary damage risk criteria (DRC) including a waveform parameter-based approach (peak SPL and B-duration), an energy-based criterion (A-weighted SEL and equivalent continuous level) and a physiological model (AHAAH). Results from these DRC were converted into a number of maximum permissible unprotected exposures to facilitate interpretation. Acoustic characteristics of firearm impulses differed substantially across guns, ammunition, and microphone location. The type of gun, ammunition and the microphone location all significantly affected estimates of auditory risk from firearms. Vast differences in maximum permissible exposures were observed; the rank order of the differences varied with the source of the impulse. Unprotected exposure to firearm noise is not recommended, but people electing to fire a gun without hearing protection should be advised to minimize auditory risk through careful selection of ammunition and shooting environment. Small-caliber guns with long barrels and guns loaded with the least powerful ammunition tend to be associated with the least auditory risk.
Adsorption of benzene and toluene from aqueous solutions onto activated carbon and its acid and heat treated forms: Influence of surface chemistry on adsorption

The influence of surface chemistry and solution pH on the adsorption of benzene and toluene on activated carbon and its acid and heat treated forms were studied. A commercial coal-based activated carbon F-400 was chosen as carbon parent. The carbon samples were obtained by modification of F-400 by means of chemical treatment with HNO3 and thermal treatment under nitrogen flow. The treatment with nitric acid caused the introduction of a significant number of oxygenated acidic surface groups onto the carbon surface, while the heat treatment increases the basicity of carbon. The pore characteristics were not significantly changed after these modifications. The dispersive interactions are the most important factor in this adsorption process. Activated carbon with low oxygenated acidic surface groups (F-400Tox) has the best adsorption capacity.
Understanding the Link Between Gender Role Conflict, Resilience, and Propensity for Suicide in Adolescent and Emerging Adult Males

This study examined the relationship between gender role conflict and propensity for suicidality in adolescent and emerging adult males using a resilience perspective. Multiple regression modeling revealed a complex relationship, namely that competition and motivation for success in males served as protective against suicidality while associating emotional disclosure with anxiety or negativity served as a risk factor. Identifying risk through assessment of the loss of protective factors in male youth can help to identify threats to positive youth development before the onset of suicidal ideation. This may be useful in studying the earlier processes in the development of suicidality.
The relaxation behavior of poly(L-proline)

Abstract Broad-line NMR measurements in the 160 to 350°K range have been carried out on poly(L-proline) Form I and Form II. Dynamic shear measurements, using a torsion pendulum, were made on poly(L-proline) Form II in the 130 to 250°K. region. Both Form I and Form II show decreases in the NMR line width in the 190 to 280°K. range, and Form II has a mechanical loss peak at 175°K (0.4 cps). The motion responsible for these processes is discussed.
Paramagnetic Relaxation in Metals

The paramagnetic relaxation time of electron spins in a metal is calculated. Relaxation processes due to interaction with lattice vibrations, nuclear spins, other electrons, and impurity atoms are treated. It is found that the most important process of those considered is due to the interaction between electron magnetic moments and the fields caused by the translational motion of other electrons. A relaxation time of about one microsecond is calculated for this interaction at room temperature, and is approximately inversely proportional to the absolute temperature.
A multi-institutional Phase III study of nabilone vs. placebo in chemotherapy-induced nausea and vomiting

Summary A prospective, randomized, double-blind, crossover study of nabilone versus placebo was undertaken in three university cancer centers to determine the antiemetic efficacy and toxicity of nabilone in patients experiencing nausea and vomiting due to cancer chemotherapy. Identical study drug (2 mg of nabilone or placebo) was given the evening before and the morning of chemotherapy and for at least 24 h afterwards on a b.i.d. schedule. Careful assessment of nausea, vomiting and finally patient preference for study drug was carried out on each of two identical courses of combination chemotherapy. Fifty-four patients were entered. Of the 24 patients fully evaluable for efficacy, nabilone significantly reduced the mean number of vomiting episodes (7 vs. 19, P P P = 0.001). Side effects were common with nabilone but acceptable and in 49 patients who were evaluable for toxicity consisted primarily of dizziness (65%), drowsiness (51%), dry mouth (31%), sleep disturbance (14%), ataxia (8%), nausea (8%) and euphoria (6%). Nabilone is an effective antiemetic agent for chemotherapy-induced nausea and vomiting.
Modifications of concretes with polymers

Abstract As society's needs for transportation, housing, and industry increase, so does the long-term demand for concrete products. At the same time, we are placing increasing functional demands on concrete, and becoming concerned as well with the conservation of energy and material resources. Optimization of the cost-performance relationship is imperative. Within the past few years, many investigators have developed new composites based on various combinations of polymers with concrete, from polymer-impregnated materials to concretes in which polymers are used to bind an aggregate together. While many developments have occurred, technology has tended to outstrip basic scientific and engineering understanding. For sophisticated design much knowledge about these composites, which have seldom been treated as such, is required. Areas of uncertainty are therefore reviewed and discussed.
Change over 70 years in a southern California chaparral community related to fire history

Abstract Question: What changes in species composition and cover have occurred in chaparral as a function of fire history across an ecoregion? Location: San Diego County, California, USA. Methods: Stands in which 40 mid-elevation chaparral vegetation plots (each 400 m2 in area) were located in the 1930s were resurveyed in 2001. We stratified the stands into Infrequently versus Frequently burned (0–1 versus 2 or more fires recorded in the 91-yr period), and Immature versus Mature (­31 yr versus >31 yr since last fire), resulting in four groups. Ten stands were randomly selected from each of these groups for survey. Results: There were no major shifts in life form composition, e.g., live oak trees were not invading chaparral that had experienced little or no fire, nor were subshrubs or herbaceous species replacing shrubs in areas that had experienced more frequent fires. However, there was a notable increase in the frequency of the subshrub Eriogonum fasciculatum across all fire history groups. In the matur...
Absorption spectra of metal atoms in solid xenon

Abstract The absorption spectra of lithium, sodium, cadmium, and mercury in solid xenon were obtained at temperatures between 4.5 and 30.0°K. The absorption spectra of the trapped atoms exhibit multiplets. These multiplets can be explained by assuming that one component is caused by isolated metal atoms in the xenon and that the remaining components are due to interacting pairs of metal atoms trapped at nonnearest-neighbor substitutional sites. The energies of the interacting pairs of atoms were obtained from the diatomic potential curves. The assignments of the isolated components were confirmed by concentration studies or by selective bleaching of the components.
On the Security of Key-Based Interval Splitting Arithmetic Coding With Respect to Message Indistinguishability

Key-based interval splitting arithmetic coding (KSAC) has been proposed to improve the security of traditional arithmetic coding (AC). Chosen-plaintext attacks have been proposed for KSAC when the same key is used to encrypt different messages. In this paper, we consider a stronger version of KSAC, where different keys are used to encrypt different messages. We then use message indistinguishability to prove that this version of KSAC is insecure under ciphertext-only attacks, a weaker form of attack than chosen-plaintext attacks. Indistinguishability in the presence of an eavesdropper is a security definition equivalent to semantic security. We prove the insecurity over the alphabet {A,B} with pB=(1/2(1+2s)) and pA=1-pB where pA and pB are the probabilities of the source generating A and B, respectively, and s is the number of bits in each splitting key.
Cognitive control functioning in hyperactive and nonhyperactive learning disabled children.

This study compared the performance of children designated as hyperactive learning disabled (HLD) and nonhyperactive learning disabled (NHLD) with a controlgroup of nonlearning disabled (nonLD) children. Results indicated that both HLD and NHLD children process information significantly less efficiently than nonLD children. However, HLD children can be differentiated further from NHLD children on several cognitive control variables viewed as critical to learning. The results are discussed in terms of differences in cognitive functioning between groups.
Higher order Godunov schemes for isothermal hydrodynamics

In this paper we construct higher order Godunov schemes for isothermal flow. Isothermal hydrodynamics serves as a good representation for several systems of astrophysical interest. The schemes designed here have second-order accuracy in space and time and some are third-order accurate for advection. Moreover, several ingredients of these schemes are essential components of even higher order. The methods designed here have excellent ability to represent smooth flow yet capture shocks with high resolution. Several test problems are presented. The algorithms presented here are compared with other algorithms having a comparable formal order of accuracy.
Prolactin differentially affects bacterial toxin-induced ADP-ribosylation of Nb2 lymphoma cell membrane proteins

Summary Exposure of lactogen-dependent Nb 2 lymphoma cells to prolactin for up to 72 hr caused time- and dose-dependent changes in the ability of specific 38 kDa and 41.5 kDa membrane proteins from these cells to be subsequently ADP-ribosylated by pertussis and cholera toxins, respectively. Whereas the sensitivity of the 41.5 kDa substrate to cholera toxin was already reduced after 1 hour, that of the 38 kDa substrate for cholera toxin was increased for up to 72 hours. These findings suggest that membrane G-proteins may mediate the effects of prolactin binding to its receptor, leading to the proliferation of Nb 2 lymphoma cells.
Identity hydride-ion transfer from C-H donors to C acceptor sites. Enthalpies of hydride addition and enthalpies of activation. Comparison with C...H...C proton transfer. An ab initio study.

Enthalpies of addition of hydride ion to eleven carbonyl acceptors (XCHO), two conjugate addition sites (XCHCH2; X = CHO, NO2), eight carbenium ion acceptors, fulvene, borane, and SiH3+ were calculated at the MP2/6-311+G** level. Correlation between calculated and experimental enthalpies of addition of hydride ion is excellent. Transition states (ts) for the identity hydride transfers between the acceptors and their corresponding hydride adducts (hydride donors) were also calculated. The carbonyl and fulvene reactions have transition states with one imaginary frequency: the hydrogen transfer coordinate. The carbenium ions, borane, and SiH3+ gave not transition states but stable compounds upon addition of the hydride donor. Computational differences between these hydride transfers and previously reported proton transfers include shorter partial C···H bonds and a tendency toward bent C···H···C angles for the hydride transfer ts and addition compound structures, particularly when a bent geometry improves in...
The clinical course of acute disseminated encephalomyelitis

The objective of this review is to describe recent advances in understanding the clinical course of pediatric and adult acute disseminated encephalomyelitis (ADEM), especially the risk of relapse and conversion to multiple sclerosis (MS). The diagnosis of ADEM is reached on clinical grounds, typically in the setting of a post-infectious meningoencephalitic syndrome associated with multifocal neurological symptoms and signs, magnetic resonance imaging (MRI) evidence of white matter lesions and exclusion of other causes. Although typically monophasic, several case series demonstrate 'multiphasic' or 'recurrent' forms of ADEM with clinical relapses occurring within a short interval of disease onset. Furthermore, the estimated risk of developing MS is substantial for both children (0-33%) and adults (approximately 35%). Advances in neuroimaging have identified some MRI features that have predictive value for a relapsing course but they are not accurate enough for therapeutic decision-making; a diagnosis of monophasic ADEM should be made with caution in all cases, especially those presenting in adulthood. Research in ADEM and related disorders remains hampered by lack of prospective studies, specific and reproducible clinical case definitions and variable follow-up methods. Standardization of these variables would facilitate identification of more accurate diagnostic and prognostic variables, discovery and testing of potential objective biomarkers that would, in turn, allow early prediction of a relapsing course and appropriate therapeutic interventions.
INTERRELATIONS OF TRAIT PERSONALITY AND SLEEP STRUCTURE VARIABLES: FURTHER NEGATIVE RESULTS

The EEG sleep characteristics of a large, healthy, aged sample (36 men and 39 women, aged 50 to 60 yr. and 19 men and 25 women, aged 60 to 70 yr.) were intercorrelated with scores from several trait personality instruments. The number of significant correlations did not exceed chance expectations. Taken together with past evidence, this finding was interpreted as reflecting the existence of only extremely limited relationships between sleep structure and trait personality variables in normal subjects.
Non-biogenic fixed nitrogen in Antarctica and some ecological implications

TOTAL fluxes of nutrients in ecosystems and the biosphere have been estimated1–3, especially for tropical and midlatitude regions, but no study has attempted to estimate the contribution of fixed nitrogen from the Antarctic ice sheet. Using data from analyses of South Pole ice, we estimate here that the mean annual accumulation of fixed nitrogen in the Antarctic ice sheet is 2.73×104 tonnes of nitrate (as N) and 1.88×104 tonnes of ammonium (as N). If annual snow accumulation approximates annual losses through calving of icebergs, blowing snow and melting of the bottom of ice shelves, then Antarctic Ocean surface waters will be enriched by 4.61×104 tonnes of NO3−N+NH4−N during the austral summer. This contribution of fixed N to circumpolar surface waters may significantly influence productivity.
Cathode drop in arcs and glow discharges

THE ARC is defined as an electrical discharge in a gas or a vapor in which the cathode drop is of the order of 10 or 20 volts and the current density to the cathode spot is of the order of hundreds or thousands of amperes per square centimeter. For an arc to exist it is necessary that there be some mechanism for producing electrons at or near the cathode. Unfortunately, there is no general agreement among physicists as to the mechanism which produces this low cathode drop with the correspondingly high current density which is characteristic of an electric arc. In this paper the author reviews briefly the different prevalent theories regarding the low cathode drop in an arc, offering discussions and interpretations based upon extensive research work carried out at the California Institute of Technology.
Verapamil for unstable angina at rest: A short-term randomized, double-blind study

To assess the efficacy of verapamil in individuals with unstable angina at rest, 11 patients (five men and six women, average age 55 years) with recurrent chest pain at rest and transient ST segment deviation (elevation or depression greater than or equal to 0.1 mV) on continuous ECG monitoring were enrolled in a 3-day double-blind, randomized study. The day before randomization (day 1), all received single-blind placebo. On day 2 they were randomized to placebo (n = 6) or verapamil, 320 mg per day (n = 5). On placebo, the number of chest pains (day 1, 2.8 +/- 2.1; day 2, 2.2 +/- 2.5; NS), nitroglycerin used (day 1, 2.7 +/- 4.4 tablets; day 2, 2.2 +/- 3.5 tablets; NS), and ST segment deviations (day 1, 8.5 +/- 5.9; day 2, 5.3 +/- 7.1; NS) did not change. On verapamil, the number of chest pains (day 1, 5.4 +/- 2.2; day 2, 1.6 +/- 2.1; p less than 0.01), nitroglycerin used (day 1, 5.0 +/- 4.5 tablets; day 2, 1.6 +/- 2.6 tablets; p = 0.057), and ST segment deviations (day 1, 12.6 +/- 4.7; day 2, 6.2 +/- 6.2; p less than 0.05) fell. Since five of six placebo patients had frequent chest pain and ST segment deviations on day 2, they were changed blindly to verapamil, 320 mg per day. Of the five verapamil patients, three had no chest pain or ST segment deviations on day 2, but two had continued chest pain and ST segment deviations and were increased blindly to 480 mg verapamil per day. Of the eight patients given verapamil (320 mg per day) on day 3, five had chest pain or ST segment deviations and were increased blindly to 480 mg verapamil per day on day 4. Of the seven who received 480 mg verapamil per day on day 4, three had chest pain and ST segment deviations similar in frequency to that occurring on day 1. Thus in patients with unstable angina at rest, verapamil exerts an initial beneficial effect, but in some individuals this salutary influence is not sustained.
Transcriptional regulation of lysophosphatidic acid-induced interleukin-8 expression and secretion by p38 MAPK and JNK in human bronchial epithelial cells

HBEpCs (human bronchial epithelial cells) contribute to airway inflammation by secreting a variety of cytokines and chemokines in response to allergens, pathogens, viruses and environmental toxins and pollutants. The potent neutrophil chemoattractant, IL-8 (interleukin-8), is a major cytokine secreted by HBEpCs. We have recently demonstrated that LPA (lysophosphatidic acid) stimulated IL-8 production in HBEpCs via protein kinase C δ dependent signal transduction. However, mechanisms of IL-8 expression and secretion are complex and involve multiple protein kinases and transcriptional factors. The present study was undertaken to investigate MAPK (mitogen-activated protein kinase) signalling in the transcriptional regulation of IL-8 expression and secretion in HBEpCs. Exposure of HBEpCs to LPA (1 μM) enhanced expression and secretion of IL-8 by 5–8-fold and stimulated threonine/tyrosine phosphorylation of ERK (extracellular-signal-regulated kinase), p38 MAPK and JNK (c-Jun N-terminal kinase). The LPA-induced secretion of IL-8 was blocked by the p38 MAPK inhibitor SB203580, by p38 MAPK siRNA (small interfering RNA), and by the JNK inhibitor JNKi II, but not by the MEK (MAPK/ERK kinase) inhibitor, PD98059. LPA enhanced the transcriptional activity of the IL-8 gene; that effect relied on activation of the transcriptional factors NF-κB (nuclear factor κB) and AP-1 (activator protein-1). Furthermore, SB203580 attenuated LPA-dependent phosphorylation of IκB (inhibitory κB), NF-κB and phospho-p38 translocation to the nucleus, NF-κB transcription and IL-8 promoter-mediated luciferase reporter activity, without affecting the JNK pathway and AP-1 transcription. Similarly, JNKi II only blocked LPA-mediated phosphorylation of JNK and c-Jun, AP-1 transcription and IL-8 promoter-mediated luciferase reporter activity, without blocking p38 MAPK-dependent NF-κB transcription. Additionally, siRNA for LPA1–3 receptors partially blocked LPA-induced IL-8 production and activation of MAPKs. The LPA1 and LPA3 receptors, as compared with LPA2, were most efficient in transducing LPA-mediated IL-8 production. These results show an independent role for p38 MAPK and JNK in LPA-induced IL-8 expression and secretion via NF-κB and AP-1 transcription respectively in HBEpCs.