cssi/SciSciGPT-SciSciNet huggingface dataset:
Density induction times in very lean mixtures of D2, H2, C2H2 and C2H4, with O2

The induction time for shock-wave-induced exothermic reaction in lean O2-D2, O2-H2, O2−C2H2, and O2−C2H4 mixtures has been measured in the constant-area shock tube using optical interferometry. For fuel/oxygen ratios of a few per cent and for 1100
Multiple-Objective (Goal) Programming Model for Feed Formulation: An Example for Reducing Nutrient Variation

Abstract A multiple-objective programming (MOP) model was applied to the feed formulation process with the objectives of minimizing nutrient variance and minimizing ration cost. A MOP model was constructed for a broiler grower ration (3 to 6 wk) and formulated with a Microsoft Excel® solver. Twenty-one ingredients with 17 nutrients were included in the formulation. Amino acids were based on digestible values. The following objectives were considered as soft constraints: (1) meeting the nutrient requirements; (2) meeting the ingredient restrictions; and (3) meeting nutrient ratios, including calcium to phosphorus and the relationship of amino acids to lysine (ideal amino acid ratios). Hard constraints considered were (1) a least-cost ration and (2) minimal nutrient variances for protein, methionine, and lysine. It was found that (1) the MOP model was more flexible in providing a compromise solution than a traditional feed formulation with a linear program, (2) the MOP model was able to handle several conflicting objectives simultaneously as compared to the traditional linear programming approach that could handle only one objective, and (3) the MOP model gave the best compromise solution that would satisfy multiple decision makers when trade-offs were made between the ration cost and minimum variances of protein and methionine. The MOP model is an efficient tool to assist the decision-making process through solving a series of linear/nonlinear programs and by interacting with decision-makers.
Unifocal eosinophilic granuloma of the temporal lobe.

The clinical features, treatment, and two-year postoperative course of a 14-year-old boy with unifocal cosinophilie granuloma of the temporal lobe are presented. A literature review of unifocal cosinophilic granuloma of the brain revealed 11 additional cases, 9 of which involved the hypothalamus and 1 each the frontal and temporal lobes. Four of the 9 patients with involvement of the hypothalamus developed multifocal disease, whereas none of the 3 who had frontal or temporal lobe involvement developed multifocal lesions. Effective therapy for cosinophilic granuloma in a single resectable site in the brain appears to be total excision. Low-dose radiation has been used to eradicate locally recurrent disease.
Solute-solvent dynamics and interactions in glassy media: Photon echo and optical hole burning studies of cresyl violet in ethanol glass

Abstract Photon echo and non-photochemical hole burning experiments on cresyl violet in ethanol glass are reported. At 1.5 K the optical dephasing time measured by the picosecond echo is eight times longer than the time measured by hole burning because of the difference in the time scales associated with the measurements. The observed temperature dependence arises from the glass's two-level systems and from a pseudolocal phonon mode at higher temperatures. Comparing the ratios of the echo to hole burning dephasing times for cresyl violet and resornfin, suggests that their dephasing is influenced by the nature of their ethanol solvation shells in addition to the dynamics of the bulk ethanol.
Genetic analysis of cleft lip with or without cleft palate in Madras, India.

We performed a genetic analysis of 331 nonsyndromic cleft lip with or without cleft palate (CLk P) proband families ascertained in Madras, India. Predictions of the multifactorial threshold (MF/T) model are tested; goodness-of-fit tests of the MFlT model and complex segregation analysis are also utilized to clarify the genetic etiology of CL ? P in this study population. There was little evidence for the MF/T model. The most reasonable conclusion from mixed model analysis is that of a major locus with reduced transmission probability. This is not altogether surprising if manifestation of CLkP also depends on in utero exposure to harmful environmental agents during the critical period of facial development, as suggested by Melnick et al. [19801 and demonstrated in an animal model of CL?P [Melnick et al., 19811. Further the results in the Madras population are quite similar to those in other populations of Europe and Asia.
Restriction enzyme cleavage of ultraviolet-damaged simian virus 40 and pBR322 DNA

Cleavage of specific DNA sequences by the restriction enzymes EcoRI, HindIII and TaqI was prevented when the DNA was irradiated with ultraviolet light. Most of the effects were attributed to cyclobutane pyrimidine dimers in the recognition sequences; the effectiveness of irradiation was directly proportional to the number of potential dimer sites in the DNA. Combining EcoRI with dimer-specific endonuclease digestion revealed that pyrimidine dimers blocked cleavage within one base-pair on the strand opposite to the dimer but did not block cleavage three to four base-pairs away on the same strand. These are the probable limits for the range of influence of pyrimidine dimers along the DNA, at least for this enzyme. The effect of irradiation on cleavage by TaqI seemed far greater than expected for the cyclobutane dimer yield, possibly because of effects from photoproducts flanking the tetranucleotide recognition sequence and the effect of non-cyclobutane (6-4)pyrimidine photoproducts involving adjacent T and C bases.
History of Ground Wave Propagation Prediction Curves for AM Standard Broadcast

The history of the FCC curves is traced from the early 1930's, when the Federal Radio Commission and later the FCC faced an intensifying need for technical information concerning interference distances. A family of curves satisfactorily meeting this need was published in 1940 based on theory. Methods for calculating these curves were reexamined recently in connection with the planned expansion of the AM broadcast band, and the resulting ground wave curves are a more precise representation of the mathematical theory.
Distributed databases for SAA

This paper describes, in general terms, distributed database and its relationship to Systems Application Architecture (SAA). It shows the importance to effective distribution of IBM's Structured Query Language (SQL), the database element of the Systems Application Architecture Common Programming Interface (SAA CPI). The paper defines five levels of distribution, showing how each fits real-world application requirements. Finally, it outlines the magnitude of the task.
Numerical simulation of aggradation and downstream fining

divers typically exhibit a tendency for grain size to become finer in the downstream direction. Data for a set of large-scale experiments on the aggradation of heterogeneous gravel have recently become available. These experiments show substantial downstream fining over several tens of meters. Here a decoupled numerical Tiodel for bed aggradation and downstream fining is developed in an attempt to test an existing gravel ransport model against the experimental data. Generally good agreement is found between the predictions and he observations in the absence of all but trivial adjustments to the gravel transport model. The same transport elation does not perform as well for a corresponding case of uniform sediment. In all of the experiments the Froude number was close to unity, a condition which would suggest that a decoupled model might break iown. Coupled and decoupled models for uniform sediment are thus compared for a case with Froude number very close to unity. They are also compared for cases in whic...
Peptide purity and counter ion determination of bradykinin by high-performance liquid chromatography and capillary electrophoresis

Abstract Bradykinin is a nonapeptide hormone of physiological importance. This peptide can be synthesized in yields as high as 83% by solid-phase synthesis. The work presented in this paper describes peptide purity determination of synthetic bradykinin acetate by both reversed-phase HPLC and CE. For purity determination by HPLC, two types of reversed-phase columns were used with gradient elution. The solvent system consisted of trifluoroacetic acid as the ion-pairing reagent and acetonitrile as the organic modifier. An LPA coated capillary and phosphate–phosphoric acid electrolytes of varied pH values were employed to determine purity by CE. The results obtained from these experiments demonstrated the high resolving power of CE in comparison to HPLC for peptide analysis. In CE, resolution of bradykinin and its impurities was greatly improved by varying the electrolyte pH. CE was also used to determine the content of acetic acid in the bradykinin sample. This was performed using a fused-silica capillary and a buffer consisting of sodium phthalate as the UV-absorbing background electrolyte and cetyltrimethylammonium bromide as the electroosmotic flow modifier under an indirect UV detection mode.
Thermodynamic properties of dilute Cu Cr alloys

Exact theoretical results for the n-channel Kondo model are used to interpret experimental data for the specific heat, susceptibility, and resistivity of dilute CuCr alloys. Reasonable agreement is obtained for S=n/2=5/2, ${\mathit{T}}_{\mathit{K}}$=1.5 K, and g factor 2, except for the susceptibility at low temperature, where interactions between impurities appear to be relevant.
Static- and dynamic-circuit models of PWM buck-derived DC-DC convertors

Indexing terms: DC-DC convertors, Pulse-width modulation, Buck-derived convertors Abstract: A systematic derivation of DC-circuit and small-signal-circuit models and characteristics for pulse-width-modulated buck-derived conver- tors operating in the continuous conduction mode is presented. Starting from voltage- and current- transfer functions of an idealised switching part of the convertor and using the linearisation tech- nique, pure linear-circuit models of lossless con- vertors are derived. To obtain the models of lossy convertors, the principle of energy conservation is used to derive an equivalent averaged resistance of all parasitic resistances and an equivalent aver- aged voltage of offset voltage sources of switches. The advantage of the models is that they can be directly utilised in standard circuit simulators. The models are especially convenient in analysing complicated convertor topologies and for includ- ing parasitic components. The proposed models lead to the same characteristics as those obtained by means of the state-space-averaging method. As an example, a forward convertor is analysed, taking into account all parasitic resistances and threshold voltages of diodes. A complete set of small-signal characteristics is given for this con- vertor. Models and expressions for DC and small- signal characteristics that account for parasitic resistances are also given for other multiswitch and transformer buck-derived convertors such as push-pull, half-bridge, and full-bridge circuits.
Interspecific aggression and dominance in Gasterosteus

The threespine stickleback, Gasterosteus aculeatus, and the blackspotted stickleback, Gasterosteus wheatlandi, are often found in close association in brackish and marine waters of the Atlantic coast of North America. When the two species are placed together into a large seminatural community tank during the breeding season they interact aggressively. G. aculeatus males prevent G. wheatlandi males from establishing territories in such tanks when individuals of the two species are introduced simultaneously. If several G. wheatlandi males are introduced alone into the tank they establish territories and nests; however, G. aculeatus males subsequently added usually displace resident G. wheatlandi males and establish their own territories. The greater body size of G. aculeatus appears to be the major factor determining the displacement of G. wheatlandi by G. aculeatus. Furthermore, when attack frequencies of the two species are compared in a series of aggression tests, G. aculeatus attains higher levels, suggesting that it is also more aggressive than G. wheatlandi. G. wheatlandi males have a stronger tendency to build nests in close proximity to vegetation than do G. aculeatus males, which is consistent with the generally less conspicuous behavior and mating coloration of G. wheatlandi. The ability of G. aculeatus to interfere with territory establishment and nesting of G. wheatlandi suggest that the slightly later breeding peak of G. wheatlandi might result from interspecific interaction.
Vortex core timelines and ribbon summarizations: flow summarization over time and simulation ensembles

We present two new vortex-summarization techniques designed to portray vortex motion over an entire simulation and over an ensemble of simulations in a single image. Linear “vortex core timelines” with cone glyphs summarize flow over all time steps of a single simulation, with color varying to indicate time. Simplified “ribbon summarizations” with hue nominally encoding ensemble membership and saturation encoding time enable direct visual comparison of the distribution of vortices in time and space for a set of simulations.
Environmental stress effects on fiber optic cable end faces

The PC and PC-NC termini studied here showed tolerable changes in optical transmittance under temperature cycling, vibration testing or mating/de-mating cycles with periodic cleaning. The flat-NC termini studied here showed much greater average change, and much greater variability, from all stimuli than the other types. We hypothesize that this is due to variation in fiber height, and was in contrast to expected variations fiber height for the PC-NC termini as well. There are substantial differences between the designs of the PC-NC and the flat-NC termini which could cause the discrepancy: 1) end face shape, 2) very short fiber attachment region inside the flat-NC terminus, 3) possible inconsistent fiber coating adhesion, or 4) stress caused from use of tight buffered cable with the flat-NC terminus. Failure analysis did not detect epoxy failure. The mate/demate test results highlight the importance of regular cleaning to prevent end face damage.
RURAL MIGRATION: WHAT ATTRACTS NEW RESIDENTS TO NON-METROPOLITAN AREAS

Understanding the reasons people move to rural communities is important if communities intend to use in-migration as away of revitalization. This study uses the experience of three non-metropolitan counties in Pennsylvania to explore which community characteristics have the greatest influence on people's decisions to move to rural areas. Personal characteristics affected how in-migrants evaluated prospective rural residential locations. Higher income in-migrants placed a high priority on job opportunities, housing quality, a short commute to work, quality of schools, and low local taxes. Lower income in-migrants were more likely to value a location near family and friends. Ability to own a home, housing costs, and local taxes also were important.
Modeling Emergency and Telemedicine Heath Support System: A Service Oriented Architecture Approach Using Cloud Computing

This paper examines the study of healthcare services provided through a telemedicine oriented Emergency Health Support System EHSS. This study caters to the needs of senior citizens, but can be extended to a larger population. The main goals are to model the support system in Service Oriented Architecture SOA using Cloud Computing and study its performance. The paper compares a system deployed in the cloud versus a co-located environment based on data gathered from the prototype. The emergency support system has a 24/7 remote healthcare monitoring of registered users and provides immediate support in case of a healthcare emergency. The telemedicine system empowers the physicians to prescribe medication based on the users' vitals, via email, instant messaging, or phone. The system can be based on the platform of Cloud Computing to not only improve performance, but also cut down on computing and networking resource requirements to a large extent. A prototype of Emergency Health Support System has been developed and the system has been modeled and tested to derive performance statistics of the system's capability.
Which elements are excited in electrical stimulation of mammalian central nervous system: a review

(1) There are data on the amount of current necessary to stimulate a myelinated fiber or cell body and/or its axon a given distance away from a monopolar electrode over the entire range of practical interest for intracranial stimulation. Data do not exist for other electrode configurations. (2) Currents from a monopolar cathode of more than 8 times threshold may block action potentials in axons. Therefore, only axons lying in a shell around the electrode are stimulated. Elements very close to the electrode may not be stimulated. Close to an electrode small diameter axons may be stimulated and larger ones may not be. (3) Most, and perhaps all, CNS myelinated fibers have chronaxies of 50-100 musec. When gray matter is stimulated, the chronaxie is often 200-700 musec. It is not clear what is being stimulated in this case. Current-duration relations should be determined for many more responses. (4) There are no current-distance or current-duration data for central finely myelinated or unmyelinated fibers. (5) It takes less cathodal current than anodal to stimulate a myelinated fiber passing by a monopolar electrode. When a monopolar electrode is near a cell body, on the opposite side from the axon, often the lowest threshold is anodal, but sometimes cathodal. Stimulation of a neuron near its cell body is not well understood, but in many cases the axon is probably stimulated. (6) Orientation of cell body and axons with respect to current flow is important. For an axon it is the component of the voltage gradient parallel to the fiber that is important. (7) The pia has a significant resistance and capacitance. Gray matter, white matter, and cerebrospinal fluid have different resistivities, which affect patterns of current flow. (8) More is known about stimulation of mammalian CNS than most workers are aware of. Much of what is unknown seems solvable with current methods.
Characterization of a Heparin Binding Site on the Heavy Chain of Factor XI

Abstract The glycosaminoglycan heparin enhances several reactions involving coagulation factor XI (FXI) including activation of FXI by factor XIIa, thrombin, and autoactivation; and inactivation of activated FXI (FXIa) by serine protease inhibitors. We examined the effect of heparin on inhibition of FXIa by the inhibitors C1-inhibitor (C1-INH) and antithrombin III (ATIII). Second order rate constants for inhibition in the absence of heparin were 1.57 × 103 and 0.91 × 103 m −1 s−1 for C1-INH and ATIII, respectively. Therapeutic heparin concentrations (0.1–1.0 units/ml) enhanced inhibition by ATIII 20–55-fold compared with 0.1–7.0-fold for C1-INH. For both inhibitors, the effect of heparin over a wide range of concentrations (10−1 to 105 units/ml) produced bell-shaped curves, demonstrating that inhibition occurs by a template mechanism requiring both inhibitor and protease to bind to heparin. This implies that FXI/XIa contains structural elements that interact with heparin. Human FXI contains a sequence of amino acids (R250-I-K-K-S-K) in the apple 3 domain of the heavy chain that binds heparin (Ho, D., Badellino, K., Baglia, F., and Walsh, P. (1998) J. Biol. Chem. 273, 16382–16390). To determine the importance of this sequence to heparin-mediated reactions, recombinant FXI molecules with alanine substitutions for basic amino acids were expressed in 293 fibroblasts, and tested in heparin-dependent assays. Inhibition of FXIa by ATIII in the presence of heparin was decreased 4-fold by alanine substitution at Lys253 (A253), with smaller effects noted for mutants A255 and A252. FXI undergoes autoactivation to FXIa in the presence of heparin. The rate of autoactivation was decreased substantially for A253 with modest decreases for A255 and A252. Substituting all four charged residues in the sequence resulted in a profound decrease in autoactivation, significantly greater than for any single substitution. Relative affinity for heparin was tested by determining the concentration of NaCl required to elute FXIa from heparin-Sepharose. Wild type FXIa eluted from the column at 320 mm NaCl, whereas FXIa with multiple substitutions (A252–254 or A250–255) eluted at 230 mm NaCl. All proteins with single substitutions in charged amino acids eluted at intermediate NaCl concentrations. The data indicate that FXI/XIa must bind to heparin for optimal inhibition by ATIII and for autoactivation. Lys253 is the most important amino acid involved in binding, and Lys255 and Lys252 also have roles in interactions with heparin.
Behavioral and physiological effect of orally administered tryptophan on horses subjected to acute isolation stress

The effect of orally administered tryptophan on horses' reaction to acute isolation stress was studied in two groups of mature mares. Group 1 consisted of six Standardbred mares, Group 2 had two Standardbreds and two Arabians. Three oral doses of tryptophan (0.1, 0.05 and 0 mg kg−1) were administered in 14 g of confectioners sugar 2 h prior to testing in a 3×3 latin square design (two mares per treatment day−1 in Group 1, one mare per treatment day−1 in two treatments and two in the third in Group 2). The horses were isolated in a totally enclosed stall (5.3 m × 4.2 m) for 15 min (isolation environment). Behavior and heart rate were recorded continuously by video camera and a heart rate monitor, respectively. Blood samples were taken by venipuncture immediately before and after isolation. Four hours after dosing the horses were placed in the stall as before, but allowed visual contact with another mare (visual contact environment). In the isolation environment, heart rate and walking-sniffing were higher (P<0.05), when the tryptophan dose was 0.1 mg kg−1 than when no tryptophan was given. There were no treatment effects on the amount of time spent standing-alert, although the mares did this more in isolation than in the visual contact environment. When the horses were in visual contact, the majority of the time across all treatments was spent standing or walking in a relaxed position. Heart rate and walking-alert, however, were highest (P<0.05) and standing or walking-relaxed was lowest (P<0.05) with a tryptophan dose of 0.05 mg kg−1 in the visual contact environment. There were no differences in blood concentrations of serotonin, dopamine or tryptophan among treatments or environments. However, there was a difference between the two breeds; the two Arabian mares having lower (P<0.001) resting serotonin concentrations than the Standardbreds. In one horse there was a dose-related reduction (P<0.01) of a sterotypic behavior (head twisting) with tryptophan regardless of environment. None of the other horses exhibited this or similar stereotypic behaviors. Tryptophan at 0.05 and 0.1 mg kg−1 increased both heart rate and activity relative to zero dose under both isolation and visual contact environments, suggesting that oral tryptophan may stimulate horses 2–4 h after dosing rather than having a sedative effect. The effect on stereotypic behavior warrants further investigation.
Who Benefits from Tax Rate Transparency? Evidence from the Laboratory

ABSTRACT: This paper provides evidence on the effects of tax rate transparency on the decisions of individuals who transact in a competitive environment. In a series of experimental markets, participants were required to generate after-tax trading profit sufficiently large to generate a specific return on investment. The degree to which the relevant tax rate was transparent to participants varied across markets. The results indicate that a lack of tax rate transparency had a negative effect on profits earned in the markets. Greater transparency led to higher profits for those who had access to the information about the relevant tax rate. In addition, the effect of greater transparency spilled over to those who did not have access to the information about the relevant tax rate. It was those participants who benefitted the most over the course of the experiment—simply by participating in markets in which the tax rate was transparent to others.
Life and Death in the Ancient City of Teotihuacan: A Modern Paleodemographic Synthesis

Life and Death in the Ancient City of Teotihuacan: A Modern Paleodemographic Synthesis. Rebecca Storey. Tuscaloosa: University of Alabama Press, 1992. xvii + 308 pp., 34 tables, 35 figures, appendix, references cited, index. $29.95 (paper). ISBN 0–8173–0559–9.
Microhabitat conditions influence mesohabitat associations and distribution of larval salamanders in headwater streams

Distribution patterns of stream biota are the result of complex interactions between individuals and their surrounding environment. Determining the spatial scale by which an organism is most influenced is paramount to understanding distribution patterns. Using a multi-scale approach, we investigated factors influencing habitat associations of larval Ambystoma barbouri (streamside salamander) and Eurycea cirrigera (southern two-lined salamander) in three Kentucky headwater streams. We used likelihood ratio G tests to identify associations between species and mesohabitat (i.e., runs, riffles, and pools), and we used microhabitat variables to predict the presence and abundance of salamanders via a priori multiple regression modeling. Ambystoma barbouri presence and abundance were influenced by conditions at micro-scales, which in turn dictated mesohabitat associations. Eurycea cirrigera were also influenced by microhabitat variables, but displayed associations to A. barbouri presence in late spring. Associations of larval salamanders to mesohabitat and microhabitat parameters shifted from early to late spring, likely in response to changes in developmental stage. The multi-scale approach of our study improved our understanding of complex relationships between larval salamanders and their surrounding environment in headwaters, and underscored the importance of (1) research investigating multiple spatial and temporal scales and (2) heterogeneous in-stream habitat to headwater biota.
Bank capital regulation and the valuation effects of Latin American debt moratoriums

Abstract We examine effects of the Mexican and Bolivian debt moratoriums on bank share prices and analyze whether bank capital regulation influences these returns. We hypothesize that investors perceived that capital deficient banks with exposure to this debt would sustain greater regulatory costs due to increased pressure from regulators to strengthen their capital bases or to reduce leverage. Consistent with this hypothesis, we find that the impact of these debt moratoriums on bank stock returns is more unfavorable for capital deficient banks than for banks that met regulatory standards of capital adequacy.
Splicing Regulation in Neurologic Disease

The importance of alternative splicing in the regulation of diverse biological processes is reflected in the growing list of human diseases associated with known or suspected splicing defects. It is becoming evident that alternative splicing plays a particularly important role in neurologic disease, which is perhaps not surprising given the important role splicing plays in generating complexity and function in the brain. This review considers the evidence that defects in regulation of splicing may underlie many types of human neurologic diseases.
Competitive Advantage and Internal Organization: Nucor Revisited

Why does the cost of organizing particular activities differ across competitors? This article explores in detail the organization of Nucor, a steel minimill that has sustained a significant cost advantage over its competitors. Nucor's past success highlights the complementarities among organizational policies and competitive advantage as well as barriers to the imitation of apparently superior organizational arrangements. The case study also suggests avenues for additional empirical and theoretical research.
Effect of prenatal hypoxia on heat stress-mediated cardioprotection in adult rat heart.

Fetal programming has profound effects on cardiovascular function in later adult life. We tested the hypothesis that chronic hypoxic exposure during fetal development downregulates endogenous cardi...
An in vivo study of the effects of x-radiation on the chromosomes of chick allantoic membranes.

The allantoic sacs of chick embryos, x-irradiated in ovo early on the fifth day of incubation, were examined for the presence of induced chromosomal abnormalities. Detection of breaks and gaps was possible for chromosome pairs 1 to 5 representing about 50% of the nuclear DNA per cell. Four of the many factors known or suspected of influencing the occurrence or detection of such cytogenetic changes were considered. They included the total radiation exposure, the length of post-irradiation incubation, the method of tissue fixation, and the staining procedure. The yield of aberrations was found to be dependent in part on radiation exposure and time. With an increase in total exposure, a proportional increase in the frequency of one-hit aberrations (gaps and breaks) was observed. The total exposure has little effect on the type of aberration produced, with similar proportions of gaps and breaks recorded at each level. Abnormalities occurred at random along the length of the chromosome in frequencies proportional to the size of the chromosome being considered. The Z chromosome was affected less often than was dictated by its size, and provided the exception to this general result. The relatively high incidence of chromosomal abnormaltties present 1 h after x-raymore » exposure decayed with time, and nearly vanished after 8 h of post-irradiation incubation. The two fixatives tested (1: 1 ethanol--acetic acid and 3: 1 ethanol-- acetic acid) seemed to be of equal value in their selective preservation of the chromosomes. Neither demonstrated any particular advantage for the detection of chromosome aberrations in spite of the enhanced despiralization produced with the 1: 1 fixative. The Giemsa and crystal violet dyes were observed to stain C-metaphase chromosomes equally well. However, the crystal violet method was simpler, faster, less sensitive to pH, and more reliable than was the Giemsa procedure. Although the stained slides offered the advantages of permanent preparations, the metaphase plates were sometimes distorted by certain antifacts resulting from freezing and air-drying. The unstained squash preparations showed relatively few antifacts and thus provided a valuable means for the observation of chromosome abnormalities. (auth)« less
Visual adaptation: retinal transduction, brightness and sensitivity.

Abstract Two types of experiments tested and confirmed the hypothesis that light-adaptation at scotopic and mesopic levels is produced by nonlinearities in the mechanisms of retinal transduction. In the brightness experiments, observers judged the terminal portion of a flash of white light composed of a test flash superimposed upon a preceding adapting field of the same size. For flashes on the order of several sec and retinal illuminances about 2 log units above absolute threshold, brightness varied as a power function of total intensity with an exponent of 1/3 independent of the level of the adapting field. The increment in brightness produced by a given test intensity at different adapting levels varied in accord with equations describing brightness in a steady-state. In the threshold experiments, increment thresholds were obtained at several levels of adaptation covering the same range of intensities used in the brightness experiments. Except near absolute threshold, increment threshold increased as a power function of adapting level with an exponent of 2/3 in accord with a prediction based upon a fixed threshold criterion of brightness. The findings are consistent with previous studies and can be used to suggest a theoretical basis for the Weber-Fechner relation.
Tolerability and effects of oral Δ9-tetrahydrocannabinol in older adolescents with marijuana use disorders

Objective The tolerability and effects of oral Δ9-tetrahydrocannabinol (THC) have been previously investigated in adult marijuana abusers. However, no studies have included adolescent participants. This double-blind laboratory study investigated the tolerability and effects of oral THC in a group of older adolescents with marijuana use disorders.
Molecular dynamics simulation of mass and charge transport in superionic conductors, and structural correlations in chalcogenide glasses

Structural properties, single-particle dynamics, and the charge transport are studied in superionic conductor Ag/sub 2/Se using the molecular dynamics (MD) technique. The calculations are based on a model of interionic potentials in which ions interact through Coulomb interaction, steric repulsion and charge-dipole interaction due to the large electronic polarizability of the selenium ions. Structural and dynamics correlations are studied at five temperatures in the superionic phase. Among the structural correlations the results are presented for partial pair correlation function, coordination numbers, bond angle distributions and wave-vector dependence of the Bragg intensities. Detailed comparison with neutron and x-ray single crystal diffraction experiments. The calculated temperature dependence of the self-diffusion constant of silver is in good agreement with the tracer diffusion measurements. The spectra of velocity autocorrelation functions and the frequency dependent ionic conductivity are calculated. The Haven's ratio is also in good agreement with experiments. 21 refs., 9 figs., 2 tabs.
Sharpening of directional responses along the auditory pathway of the oyster toadfish, Opsanus tau

Our previous studies have shown that the peripheral auditory system of the toadfish encodes the direction of a sound source. Here, we compare directional responses of peripheral saccular afferents, cells in the descending octaval nucleus (DON) of the medulla, and the torus semicircularis (TS) of the midbrain. Recording locations in the brain were labeled with neurobiotin to confirm the site. To compare directional responses among cells, we calculated an index [sharpening ratio (SR)] that weights the relative strength of responses to the best direction for that cell and to the adjacent stimulus angles tested. Unsharpened saccular afferents tend to have a cosinusoidal directional response pattern (DRP) with an expected SR of 0.87. In DON, more than 60% of the cells exhibited directional sharpening (defined as SR <0.8). In TS, more than 80% of the cells exhibited directional sharpening. We conclude that directional auditory sharpening first occurs in DON and some additional sharpening occurs in the ascending pathway to the midbrain, particularly in azimuth. The sharpening of directional selectivity is likely to be an important component of the neural computations underlying directional hearing.
Depression in Older Adults: A Meta-Synthesis

Depression in older adults is often overlooked and dismissed as a part of aging. A body of knowledge-both quantitative and qualitative-has developed on the topic of depression in older adults. Meta-analyses and systematic reviews have been used to synthesize the quantitative findings of studies, and our research seeks to synthesize the qualitative studies that have been conducted on elders' experience with depression. Thirteen studies met inclusion criteria, and 4 major themes were extracted: experiences, causes, recovery, and barriers to treatment. These themes are detailed and their implications for practice are explored.
Regulation of canine renal vesicle Pi transport by growth hormone and parathyroid hormone

Renal phosphate (Pi) reabsorption is increased by growth hormone (GH) and decreased by parathyroid hormone (PTH). Na+-stimulated Pi transport across the brush border membrane of the proximal tubule is the initial step in the process of Pi reabsorption. To determine whether changes in Pi reabsorption induced by GH or PTH are accompanied by changes in brush border membrane Na+-gradient-stimulated Pi transport, we examined the effect of in vivo GH and PTH administration and thyroparathyroidectomy on Pi transport by isolated brush border membrane vesicles prepared from canine kidney. In experiments in which the effect of PTH administration was examined, the same animal provided the control kidney (before PTH administration) and the experimental kidney (after PTH administration). The Na+-gradient Pi overshoot in vesicles isolated from normal, GH-treated and thyroparathyroidectomized dogs was increased after in vivo PTH administration. GH administration and thyroparathyroidectomy increased the height of the overshoot compared to normal. PTH administration decreased the apparent V value by 44% in vesicles from normal animals. The apparent V value was increased, compared to normal, by GH (34%) and thyroparathyroidectomy (57%). PTH administration decreased the apparent V in both the latter groups. GH administration to thyroparathyroidectomized dogs further increased the apparent V. Changes in the apparent V paralleled changes in Pi reabsorption in vivo induced by experimental manipulations. We conclude that changes in renal Pi reabsorption induced by GH were like those induced by PTH, accompanied by changes in the Na+-stimulated Pi transport system in the renal brush border membrane, and that the effect of PTH on vesicular Pi transport in GH-treated dogs did not differ from the effect on vesicles from normal animals.
Hepatotoxicity studies with primary cultures of rat liver cells.

A method for preparing primary monolayer cultures of postnatal rat hepatocytes has been developed in our laboratory. Growing cultures in arginine-deficient medium inhibits fibroblast overgrowth, and relatively pure cultures of parenchymal hepatocytes are obtained. This cell culture system has been used to study the cytotoxicity of two hepatotoxic agents, tetracycline and norethindrone. Caffeine was evaluated as an agent thought to be relatively nontoxic to liver. Cytotoxicity was evaluated by phase-contrast microscopy of cellular morphology and by measurement of leakage of intracellular enzymes [arginosuccinate lyase (ASAL), lactate dehydrogenase (LDH), glutamate oxaloacetate transaminase (GOT), glutamate pyruvate transaminase (GPT), and acid phosphatase (AP)] into the culture medium. Hepatic cultures were treated with each of the agents in concentrations ranging from 5×10−6 to 1×10−3 m and for durations from 1 to 24 hr. ASAL was found to be the most sensitive in predicting early cell injury and AP the least sensitive; the other three enzymes tested were intermittent in value and equally sensitive in evaluating cytotoxicity. Treatment of the cultures with tetracycline (5×10−4 m) for 6 hr resulted in ASAL leakage that was 400% of control values; and norethindrone (5×10−4 m) for 6 hr caused a 250% increase relative to controls. The hepatotoxic agents demonstrated a dose- and timedependence of cytotoxicity in the cultures. In contrast, caffeine was relatively nontoxic to the cultures.
Co-oxidation of the Sulfur-Containing Amino Acids in an Autoxidizing Lipid System

SUMMARYM Oxidation of the sulfur amino acids by autoxidizing lipids was studied in a model system consisting of an amino acid dispersed in cold-pressed, molecularly distilled menhaden oil (20–80% w/w). Under all conditions investigated, cysteine was oxidized completely to cystine. Preliminary results suggest that at 110°C the oxidation follows first-order kinetics for at least the first 8 hr. A specific reaction rate constant of 0.25 per hour was calculated. When fatty acids were added to the system, cystine was oxidized to its thiosulfinate ester. When the fatty acid-cystine ratio was 1:2, oxidation of cystine was a maximum. No oxidation of cystine occurred unless either a fatty acid, volatile organic acid, or ethanol was added. Under the conditions investigated, methionine was not oxidized to either its sulfoxide or its sulfone.
Determination of levoglucosan in atmospheric fine particulate matter.

Abstract A microanalytical method suitable for the quantitative determination of the sugar anhydride levoglucosan in low-volume samples of atmospheric fine particulate matter (PM) has been developed and validated. The method incorporates two sugar anhydrides as quality control standards. The recovery standard sedoheptulosan (2,7-anhydro-β-D-altro-heptulopyranose) in 20 μL solvent is added onto samples of the atmospheric fine PM and aged for 1 hr before ultrasonic extraction with ethylacetate/ triethylamine. The extract is reduced in volume, an internal standard is added (1,5-anhydro-D-mannitol), and a portion of the extract is derivatized with 10% by volume N-trimethylsilylimidazole. The derivatized extract is analyzed by gas chromatography/mass spectrometry (GC/MS). The recovery of levoglucosan using this procedure was 69 ± 6% from five filters amended with 2 μg levoglu-cosan, and the reproducibility of the assay is 9%. The limit of detection is ∼0.1 μg/mL, which is equivalent to ∼3.5 ng/m3 for a 10 L/mi...
Quartz Enhanced Photoacoustic Spectroscopy: Today and Beyond

Current theoretical understanding and practical applications of the trace gas sensing technique called quartz enhanced photoacoustic spectroscopy (QEPAS) will be presented. Work in progress and planned QEPAS developments will be discussed.
The synthesis of branched-chain, deoxy sugars by sugar epoxide-grignard reagent reactions

Abstract Alkylmagnesium chlorides react with methyl 2,3-anhydro-4,6- O -benzylidene-α- d -mannopyranoside ( 1 ) and -α- d -allopyranoside ( 2 ) to give, preponderantly, 3-alkyl and 2-alkyl, branched-chain, deoxy sugars. In contrast, alkylmagnesium iodides and bromides do not give branched-chain, deoxy sugars with 1 and 2 but give, initially, halohydrins which undergo elimination and reduction with excess of Grignard reagent. Preliminary investigations of the reaction of 2 with a complex derived from alkyl-magnesium iodides and tetrahydropyran indicate the formation of methyl 4,6- o -benzylidene-3-deoxy-3-iodo-α- d -glucopyranoside ( 13b ) by trans -diequatorial opening of epoxide 2 , whereas normal Grignard reagents (alkylmagnesium iodides) react with 2 in tetrahydropyran to give the usual trans -diaxial product ( 14b ).
Electrophysiological correlates of visual detection in the cat.

Abstract Average evoked responses to near-threshold visual stimuli were recorded from 9 cats as they performed a stimulus detection task. The amplitude of response components in the optic tract and striate cortex was a logarithmic function of stimulus intensity. The amplitude of early response components in the lateral geniculate nucleus (LGN) and mesencephalic reticular formation (MRF) was predominantly a function of probability-of-seeing. Day to day variations in stimulus detectability were accompanied by corresponding changes in early response components at the LGN and MRF but not in responses in the optic tract and striate cortex. This indicates that a cat performing a stimulus detection task uses an early subcortical detecting system.
The Early History of Greed: The Sin of Avarice in Early Medieval Thought and Literature

List of abbreviations Preface 1. Alms and ascetes, round stones and masons: avarice in the early church 2. Ascetic transformations I: monks and the laity in eastern Christendom 3. Ascetic transformations II: soaring eagles or safety in the herd - from anchoritic to cenobitic monasticism 4. Ascetic transformations III: the Latin west in the fourth and fifth centuries 5. Secularizing avarice and cupidity Epilogue: Future perspectives Appendix Notes Bibliography Indexes.
Toll Receptors Instruct Axon and Dendrite Targeting and Participate in Synaptic Partner Matching in a Drosophila Olfactory Circuit

Our understanding of the mechanisms that establish wiring specificity of complex neural circuits is far from complete. During Drosophila olfactory circuit assembly, axons of 50 olfactory receptor neuron (ORN) classes and dendrites of 50 projection neuron (PN) classes precisely target to 50 discrete glomeruli, forming parallel information-processing pathways. Here we show that Toll-6 and Toll-7, members of the Toll receptor family best known for functions in innate immunity and embryonic patterning, cell autonomously instruct the targeting of specific classes of PN dendrites and ORN axons, respectively. The canonical ligands and downstream partners of Toll receptors in embryonic patterning and innate immunity are not required for the function of Toll-6/Toll-7 in wiring specificity, nor are their cytoplasmic domains. Interestingly, both Toll-6 and Toll-7 participate in synaptic partner matching between ORN axons and PN dendrites. Our investigations reveal that olfactory circuit assembly involves dynamic and long-range interactions between PN dendrites and ORN axons.
A comparison of tablets with oral suspension formulation of dipyridamole in thallium myocardial imaging.

Dipyridamole stress thallium imaging has been widely employed to diagnose and assess the extent of coronary heart disease in patients who cannot exercise. When oral dipyridamole administration was used, a wide range of results for sensitivity, specificity, hemodynamic response and side effect profile has been reported. The authors hypothesized that the formulation used for oral administration of dipyridamole plays a major factor in this variability, and that the pulverized form of dipyridamole will achieve faster and more consistent response than the standard tablet form. The authors studied 13 consecutive patients who underwent thallium scintigraphy. Eight patients received dipyridamole pulverized and dissolved in a glycol/aqueous base diluent (group A), and jive patients received the standard form of dipyridamole (group B). In group A, mean peak systolic blood pressure decreased from 142 ± 31 (mean ± standard deviation) to 109 ± 30 (P = .05), and mean diastolic blood pressure decreased from 76 ± 14 to 51 ± 5. The mean heart rate changed from 78 ± 26 to 80 ± 10. In group B, baseline systolic blood pressure was 165 ± 12 and decreased to 156 ± 7 at 45 minutes and to 155 ± 14 at 90 minutes. Heart rate increased from baseline of 69 ±9 to 75 ±8 at 45 minutes and to 76 ± 11 at 90 minutes. At 45 minutes, the systolic blood pressure of the 8 group A patients dropped by 33 ± 19 mm Hg, whereas group B's changed by 9 ± 6 mm Hg (P < .005). The total dipyridamole dose used was significantly lower for group A as compared with group B (425 ± 66 mg and 800 mg, respectively; P < .0001). The time from start until thallium injection was shorter for group A (33 ± 7 minutes) as compared with 90 minutes for group B (P < .001). Sixty-three percent of the patients who received the pulverized dipyridamole had a reversible perfusion defect on thallium imaging, but no patient had a positive study in group B. Side effects were observed in one patient receiving pulverized dipyridamole (13%), whereas 2 of 5 patients (40%) receiving tablets had side effects at 90 minutes and 4 of 5 patients (80%) had side effects between 90 and 180 minutes. The authors conclude that yield at thallium imaging with dipyridamole tablets is low, and late side effects appear high. Pulverized dipyridamole appears to be a sensitive provocative agent for thallium imaging with mild side effects over a shorter period.