cssi/SciSciGPT-SciSciNet huggingface dataset:
Characteristics of Passing and Meeting Maneuvers on Exclusive Bicycle Paths

The findings are presented of a comprehensive analysis of the characteristics of passing and meeting maneuvers of bicycles traveling on an exclusive bicycle path 3 m (10 ft) wide. The study is based on bicycle location data collected every 0.5 s from video images of bicycle traffic scenes recorded in Denver, Colorado. For passing maneuvers, the average speeds of passing and passed bicycles, the relationship between passing and passed bicycle speeds every 0.5 s, comfortable speed difference threshold, lateral spacing during passing, average passing lengths, and the shape of passing are reported. For meeting maneuvers, statistics about the average speed and lateral spacing are included; for paired riding, headway and lateral spacing statistics are included. The results also show that the average bicycle speeds estimated are significantly higher than the speeds reported from a study conducted in the Netherlands. These findings can be used to develop more accurate procedures for the analysis of the quality of...
Comments on normalizing the reduced strain rate for stress reduction analysis

The stress reduction behavior of a class M material can be analyzed on a semilogarithmic plot of reduced strain rate (kr) normalized by the strain rate prior to the stress reduction (ko) versus reduced stress (o) normalized by the stress prior to the stress reduction (Oo) [1]. The stress reduction behavior of class M materials on such a plot consists of two branches. A low stress sensitivity branch is observed at large stress reductions (small O/Oo) and a high stress sensitivity branch is observed at small stress reductions (large O/Oo) [2]. The slope of the high stress sensitivity branch can be used to determine the true activation area of the deformation mechanism [2,3]. Usually, stress reduction experiments are performed in the steady state strain rate region, i.e, region II on a semilogarithmic plot of strain rate versus strain, and therefore the reduced strain rate is normalized by a constant. However, for some materials a steady state strain rate region does not occur. The question that needs to he answered is whether the strain rate prior to the stress reduction should he used to normalize the reduced strain rate when a steady state strain rate does not occur? The objective of this paper is to determine what strain rate should he used to normalize the reduced strain rate for materials without a steady state strain rate region, and to determine what effect the choice of normalization factor has on the true activation area.
Differential effects of glucose and alcohol on reactive oxygen species generation and intranuclear nuclear factor-κB in mononuclear cells

It has previously been shown that oral intake of 300 calories of glucose (75 g), lipid, or protein increases reactive oxygen species (ROS) generation by polymorphonuclear cells (PMNL) and mononuclear cells (MNCs). We investigated the effects of 75 g glucose on proinflammatory transcription factor, nuclear factor-kappaB (NFkappaB), in mononuclear cells. To further investigate whether the effects of macronutrient-induced oxidative stress are due to consumption of calories or are nutrient specific, we investigated the effects of acute oral challenge of equicaloric amounts of alcohol (300 calories) on ROS generation and NF-kappaB activation in MNCs and PMNL and compared them with those of glucose and water (control). Sixteen normal healthy adult volunteers were given either vodka (10 subjects), glucose solution (10 subjects), or 300 mL water (7 subjects). Vodka and glucose drinks were equivalent to 300 calories. We measured ROS generation and intranuclear NF-kappaB activation by PMNL cells and MNCs at 1 hour, 2 hours, and 3 hours following ingestion. ROS generation by both MNC and PMNL increased significantly (P <.05 for MNC and P <.01 for PMNL) following intake of glucose solution, but did not change significantly following alcohol or water. NF-kappaB binding activity in MNC nuclear extracts also increased (P <.001) following ingestion of glucose solution, but did not change after the administration of alcohol or water. We conclude that (1) 75 g oral glucose increases NF-kappaB binding activity in MNCs. (2) While 75 g glucose (300 calories) induces an increase in ROS generation and intranuclear NF-kappaB, equicaloric amounts of alcohol did not produce these effects.
Development and verification of real-time controllers for the F/A-18 vertical fin buffet load alleviation

Twin-tail fighter aircraft such as the F/A-18 may experience intense buffet loads at high angles of attack flight conditions and the broadband buffet loads primarily excite the first bending and torsional modes of the vertical fin that results in severe vibration and dynamic stresses on the vertical fin structures. To reduce the premature fatigue failure of the structure and to increase mission availability, a novel hybrid actuation system was developed to actively alleviate the buffet response of a full-scale F/A-18 vertical fin. A hydraulic rudder actuator was used to control the bending mode of the fin by engaging the rudder inertial force. Multiple Macro Fiber Composites actuators were surface mounted to provide induced strain actuation authority to control the torsional mode. Experimental system identification approach was selected to obtain a state-space model of the system using open-loop test data. An LQG controller was developed to minimize the dynamic response of the vertical fin at critical locations. Extensive simulations were conducted to evaluate the control authority of the actuators and the performance of the controller under various buffet load cases and levels. Closed-loop tests were performed on a full-scale F/A-18 empennage and the results validated the effectiveness of the real-time controller as well as the development methodology. In addition, the ground vibration test demonstrated that the hybrid actuation system is a feasible solution to alleviate the vertical tail buffet loads in high performance fighter aircraft.
Murine CD5+, CD8+ Normal Fetal Liver Cells Enhance an Immune Response: Benzo(α) Pyrene-Exposed CD5+ Fetal Liver Cells are Inhibitors

The effects of 150 ug benzo(α)pyrene/gm body weight given intraperitoneally to the pregnant mouse at mid-gestation leads to long-lasting (> 18 months post-birth) immune deficiency in the progeny. Although the progeny are immunodeficient their T cell subsets induced marked enhancement and/or inhibition of cell proliferation in an immune response. Earlier we saw a striking increase (up to 7-fold) in CD8+ cells in the 18 day gestation liver of benzo(α)pyrene-exposed fetuses. We hypothesized that immune deficiency in carcinogen-exposed progeny could be attributed to an increase in classical CD8+ suppressor T-cells. Surprisingly, however, we found that CD8+ and CD5+ (Lyt 1+) cells of normal fetal liver enhance cell proliferation in an immune response. However, liver CD5+ cells from benzo(α)pyrene-exposed fetuses led to a dramatic reduction of the enhancing effect. Thus, as a novel finding, it appears that the profile of CD5+ cells, under the ontogenic influence of benzo(α)pyrene, transforms from cells that nor...
Pain measurement and experience.

Abstract Issues and developments in clinical pain assessment will be considered. The focus will be on measuring pain, rather than degree of relief. Three main response channels may be distinguished: subjective, behavioral and physiological, although the latter will not be elaborated upon here. The measurement of subjective report of pain, although an anathema to behaviorists, continues to be one og the most widely used measures. Recent developments in assessing verbal report, of the form of questionnaires and ratings derived from psychophysical scaling methods, will be reviewed. Although behavioral indices at first sight lend themselves to well-established methods of measurement, issues in establishing rather than assuming the reliability and validity of such measures will be considered. Parallel monitoring across response channels, as well as attending to questions concerning the psychometric adequacy of measures employed, will both further our understanding of pain mechanisms and provide sound indications as to treatment efficacy.
Attenuated reovirus type 3 strains generated by selection of haemagglutinin antigenic variants.

Infection of suckling mice with mammalian reovirus type 3 results in fatal encephalitis associated with marked destruction of neurones1–4. The viral tropism specific to neural cells is determined by the reovirus haemagglutinin3,4. This haemagglutinin (HA), the σ1 polypeptide, is encoded in the S1 dsRNA segment5,6. In addition to determining cell and tissue tropism, the viral haemagglutinin determines humoral and cellular immune specificity7–10, binding to cellular micro-tubules11 and inhibition of cellular DNA synthesis12. To elucidate the structural basis for the functions of the reovirus type 3 HA, we have recently isolated and characterized several anti-HA monoclonal antibodies, which we have used to show that there are distinct functional domains on the reovirus type 3 HA13. One group of monoclonal antibodies neutralizes viruses while a second inhibits haemagglutination. Thus there are distinct HA functional domains involving haemagglutination and neutralization. One of the neutralizing monoclonal antibodies was used to select reovirus antigenic variants that were no longer neutralized by the monoclonal antibodies. These ‘variant’ viruses were tested for their neurovirulence by determining their capacity to replicate in mouse brains, leading to fatal encephalitis. We report here that all variants are markedly less virulent then the parental type 3 virus from which they were selected. These findings demonstrate directly the critical role of the viral haemagglutinin in neurovirulence and show that variant viruses that are altered at a site recognized by neutralizing antibody cannot grow efficiently in neural tissue.
Concerning the anisotropy of the polarizability tensor of pairs of methane molecules

Abstract The depolarized Raman spectrum of collisional pairs of methane molecules is obtained over a range of intensities exceeding two orders of magnitude, and at densities low enough (1.8 amagat) to suppress all three-body contributions. Absolute intensities are determined relative to a nitrogen rotational Raman line of known intensity. The experimental spectrum is reproduced from theory in all detail if the dipole-induced dipole (DID) approximation of the anisotropy of the pair polarizability tensor is used. Other models of the anisotropy are inconsistent with experiment unless they differ by less than about 5% near 3.82Ainternuclear separation.
Preoperative pulmonary rehabilitation before lung cancer resection: Results from two randomized studies

Complete surgical resection is the most effective curative treatment for lung cancer. However, many patients with lung cancer also have severe COPD which increases their risk of postoperative complications and their likelihood of being considered "inoperable." Preoperative pulmonary rehabilitation (PR) has been proposed as an intervention to decrease surgical morbidity but there is no established protocol and no randomized study has been published to date. We tested two preoperative PR interventions in patients undergoing lung cancer resection and with moderate-severe COPD in a randomized single blinded design. Outcomes were length of hospital stay and postoperative complications. The first study tested 4 weeks of guideline-based PR vs. usual care: that study proved to be very difficult to recruit as patients and providers were reluctant to delay surgery. Nine patients were randomized and no differences were found between arms. The second study tested ten preoperative PR sessions using a customized protocol with nonstandard components (exercise prescription based on self efficacy, inspiratory muscle training, and the practice of slow breathing) (n=10) vs. usual care (n=9). The PR arm had shorter length of hospital stay by 3 days (p=0.058), fewer prolonged chest tubes (11% vs. 63%, p=0.03) and fewer days needing a chest tube (8.8 vs. 4.3 days p=0.04) compared to the controlled arm. A ten-session preoperative PR intervention may improve post operative lung reexpansion evidenced by shorter chest tube times and decrease the length of hospital stay, a crude estimator of post operative morbidity and costs. Our results suggest the potential for short term preoperative pulmonary rehabilitation interventions in patients with moderate-severe COPD undergoing curative lung resection. 4 weeks of conventional preoperative PR seems non feasible.
9.3.1 Path Dependence and Network Effects and How they Affect the Engineering and Integration of Systems

Path dependence is discussed in terms of how it relates to the engineering of systems. A related phenomenon is network externalities. These two concepts will be described with respect to standards, requirements, architecture, intellectual property, time to market, and the spiral development approach. There will also be a discussion of how path dependence and network externalities influence systems integration at the level of product, process, and policy.
HYPERAHMONEMIA IN PREMATURE INFANTS

Plasma levels of ammonium, glutamine, glutamate, alanine, α-ketoglutarate and urinary excretion of orotate were measured in full-term, n=41, premature small for gestational age (SGA), n=9, and premature appropriate for gestation age (AGA), n=27, infants. At 0-3 days of Hfe there was a significant difference (p<.001) in plasma ammonium concentrations in the premature SGA and AGA infants (mean±SEM) 45±3. 47±2 μM as compared to the full-term infants, 27±1 μM (adult normal <30 μM). When the two premature groups reacned term by weight or gestational age they were still hyperammonemic (39±3, 47±3 μM). It was not until 6-8 weeks of postnatal age that plasma ammonium levels became normal in all the prematures (29±1 μM). Associated with the hyperammonemia was a significant (p<.01) decrease of plasma α-keto-glutarate concentration, 12±1 μM, in premature AGA (n=13), compared to 22±1 μM in full-term (n=17) infants and an increase (p<.05) in urinary orotate excretion, 9±2 as compared to 4±1 μg/mg creatinine. There was a significant, p<.001, relationship between birth weight and plasma ammonium concentration (r=-0.65) and between α-keto-glutarate and plasma ammonium levels (r=-0.86). There were no differences in the plasma concentrations of glutamine, glutamate or alanine. Both premature groups were α-symptomatic. Possible mechanisms responsible for these abnormalities include development delay of one or more of the enzymes related to the urea cycle or urea cycle substrate deficiency.
Exploratory Study of the Occupational Health and Health-Seeking of Migrant and Seasonal Farmworkers on the U.S.–Mexico Border

The U.S. migrant and seasonal farmworker (MSFW) workforce is aging. Aging causes functional changes that can affect work performance and increase injury/accident risk. It also has been linked with deferred health-seeking. The exploratory study was conducted to investigate occupational injuries and health-seeking in Hispanic MSFW on the U.S.–Mexico border. Data were collected using an abbreviated Spanish-version of the California Agricultural Worker Health Survey. Nearly 60% of the 141 participants were middle-aged or older. Musculoskeletal injuries and those consistent with agrochemical and environmental exposures were common. Farmworkers aged >40 years were 2.5–5 times more likely than younger MSFW to report persistent single and multiple injuries involving the knees, shoulder, feet, and hands. Except for neck and back injuries, few received any medical treatment. Although many self-treated with traditional home remedies, few used CAM practitioners. The study findings highlight the multiple workplace health and health-seeking challenges faced by aging immigrant MSFW.
An experimental and modelling study of polybutadiene functionalization to polyaldehydes using a homogeneous rhodium catalyst

Abstract Results are presented on a novel application of catalysis and reaction engineering to the chemical modification of commercially available polybutadiene polymers. The functionalized polyaldehyde products are key intermediates in the development of various polymer derivatives which form the basis for various novel material and component applications, such as the manufacture of automobile body components by reaction injection molding processing. The particular polyaldehydes examined here are formed through the liquid-phase hydroformylation of a low molecular weight polybutadiene consisting of 12 wt% 1,2 and 88 wt% 1,4 cis/trans isomers using Wilkinson's homogeneous rhodium catalyst precursor with excess triphenylphosphine. Characterization of the reaction products using 13 C and 1 H NMR shows that the olefin units in the polybutadiene are selectively hydroformylated to the 1,2 terminal branched and 1,4 internally branched aldehyde products. Additional characterization using gel permeation chromatography with total mass and aldehyde group specific detectors shows that the aldehyde addition is reasonably uniform over the entire range of polymer molecular weight. Interpretation of intrinsic kinetic data shows that the global reaction rate can be described by a power-law type relationship with fractional order dependence on olefin unit and catalyst concentration. Use of this rate equation to predict the performance of a mechanically agitated reactor for use in preliminary process design and development of process economics is also described.
Modulation of Small-Scale Turbulence by Ducted Gravity Waves in the Nocturnal Boundary Layer

Abstract Constant altitude measurements of temperature and velocity in the residual layer of the nocturnal boundary layer, collected by the Cooperative Institute for Research in Environmental Sciences (CIRES) Tethered Lifting System (TLS), exhibit fluctuations identified by previous work (Fritts et al.) as the signature of ducted gravity waves. The concurrent high-resolution TLS turbulence measurements (temperature structure constant C2T and turbulent kinetic energy dissipation rate e) reveal the presence of patches of enhanced turbulence activity that are roughly synchronized with the troughs of the temperature and velocity fluctuations. To investigate the potentially dominant role ducted gravity waves might play on the modulation of atmospheric stability and therefore, on turbulence, time series of the wave-modulated gradient Richardson number (Ri) and of the vertical gradient of potential temperature ∂θ/∂z(t) are computed numerically and compared to the TLS small-scale turbulence measurements. The resu...
A mathematical magnetospheric field model with independent physical parameters

Abstract A quantitative magnetospheric magnetic field model has been calculated in three dimensions. The model is based on an analytical solution of the Chapman-Ferraro problem. For this solution, the magnetopause was assumed to be an infinitesimally thin discontinuity with given geometry. The shape of the dayside magnetopause is in agreement with measurements derived from spacecraft boundary crossings. The magnetic field of the magnetopause currents can be derived from scalar potentials. The scalar potentials result from solutions of Laplace's equation with Neumann's boundary conditions. The boundary values and the magnetic flux through the magnetopause are determined by all magnetic sources which are located inside and outside the magnetospheric cavity. They include the Earth's dipole field, the fields of the equatorial ring current and tail current systems, and the homogeneous interplanetary magnetic field. In addition, the flux through the magnetopause depends on two constants of interconnection which provide the possibility of calculating static interconnection between magnetospheric and interplanetary field lines. Realistic numerical values for both constants have been derived empirically from observed displacements of the polar cusps which are due to changes in the orientation of the interplanetary field. The transition from a closed to an open magnetosphere and vice versa can be computed in terms of a change of the magnetic boundary conditions on the magnetopause. The magnetic field configuration of the closed magnetosphere is independent of the amount and orientation of the interplanetary field. In contrast, the configuration of the open magnetosphere confirms the observational finding that field line interconnection occurs primarily in the polar cusp and high latitude tail regions. The tail current system reflects explicitly the effect of dayside magnetospheric compression which is caused by the solar wind. In addition, the position of the plasma sheet relative to the ecliptic plane depends explicitly on the tilt angle of the Earth's dipole. Near the tail axis, the tail field is approximately in a self-consistent equilibrium with the tail currents and the isotropic thermal plasma. The models for the equatorial ring current depend on the Dst-parameter. They are self-consistent with respect to measured energy distributions of ring current protons and the axially symmetric part of the magnetospheric field.
Magnetic Field Confinement in the Solar Corona. II. Field-Plasma Interaction

The numerical study of axisymmetric force-free magnetic fields in the unbounded space outside a unit sphere, presented in the first paper of this series, is extended to treat twisted fields in static equilibrium with plasma pressure and weight in a polytropic atmosphere. The study considers dipolar magnetic fields all sharing the same boundary flux distribution on the unit sphere and characterized with (1) a nonlinear distribution of its azimuthal field component expressed as a power of the poloidal flux function and (2) a plasma distribution varying linearly with the poloidal flux function. Nonlinear boundary value problems are solved numerically to generate a continuum of solutions with two parameters to control the total azimuthal flux and the strength of field-plasma interaction. The study includes the force-free fields of the first paper as a special case. Models with polytropic indices ? = 7/6, 14/11 are treated to show the interplay between the degree of magnetic twist and hydrostatic stratification in determining atmospheric structures, with particular interests in magnetic flux ropes and their storage of magnetic energy and azimuthal flux at levels above those bounds applicable to force-free fields. The concluding discussion relates physical insights from the study to the solar corona and the energetics of coronal mass ejections and flares.
Spatial and temporal receptive-field analysis of the cats geniculocortical pathway

Abstract Receptive field (RF) properties of lateral geniculate (LGN) and cortical visual neurons were studied in cats using computer-controlled bar and edge stimuli. Responses to stationary presentations of an optimally oriented bright bar in an array of closely spaced RF positions provided detailed spatial and temporal information about RFs. Moving edge stimuli represent a more nearly normal viewing situation, and responses provide additional information for classifying RFs. Our results allow inferences about the nature of input connections to conical units. Responses of simple striate cells and X cells of LGN were similar to each other and quite different from those of complex and Y-LGN cells. Simple and X cells exhibited spatially segregated regions of excitation and inhibition and large shifts in response latency as a function of stimulus position. Both cell types showed spatially nonoverlapping regions of response (discharge zones) to moving bright and dark edges. These results provide correlational evidence that simple cells of striate cortex receive input predominantly from X-LGN cells. X-LGN cells respond to increases or decreases in local stimulus flux, depending on stimulus position, and via separate (from segregated RF areas) projections to the cortex determine contrast polarity of the cortical response. Complex cells, on the other hand, exhibited transient responses to both stimulus onset and removal. with a constant response latency across the entire RF. Results from the same test on Y-LGN cells were strikingly similar to those for complex cortical cells. However, complex cells show far more overlap in edge discharge zones than either on- or off-center Y-LGN cells. This comparison suggests spatially overlapping input to complex cells from both on-and off-center Y-LGN cells. A third type of cortical cell (in area 18) demonstrated edge and static-bar responses that strongly resembled those of either on-or off-center Y-LGN cells. Input to these parastriate cortical cells apparently derives from either on-or off-center Y-LGN cells. We believe that these units represent the parastnate equivalent of striate simple units in that they seem to receive inputs from spatially segregated RF areas, in this case of Y-LGN units.
Factors Controlling Rates of Bluff Recession at Two Sites on Lake Michigan

Abstract Empirical relationships between recession rate of bluffs and precipitation, storm frequency, lake level, deep water wave power, and wave impact height are derived for two Lake Michigan shoreline reaches in Wisconsin. Recession rates are determined from digital orthophotos constructed using historical aerial photographs at least once every decade from the 1940s to present. The recession measurements represent spatial averages of rates measured at increments of 10-20 m along the shoreline over a distance of about 500–700 m. The temporal variations in recession rates over intervals ranging between 6 and 17 years were determined for the toe and crest at the sites with high (30–45 m) bluffs and for the crest, but not the toe at the site with low (9–11 m) bluffs. Trends in precipitation, storm frequency, and deep water wave power show weak relationships with changes in bluff recession rate. Both the toe of the high bluffs and the crest of the low bluffs show temporal recession-rate patterns that closely match the changes in the average lake-water level. The crest of the high bluffs recedes at a rate that is relatively insensitive to lake level changes. The annual average of the peak monthly wave-impact height appears to be the best predictor of bluff recession rate over the intervals studied.
Clinical observations on a contracting amalgam alloy.

RESEARCH has clearly indicated that the cause of amalgam failures, other X than those due to improper cavity preparation, can no longer be attributed to the use of an inferior alloy, but rather to the improper use of a good alloy.' Specifications established by the American Dental Association have assured the dentist alloys of good physical properties, but all of the properties are seriously altered by certain manipulative variables. The dimensional change, in particular, fluctuates greatly with trituration time, moisture contamination, and packing pressure. A slight undertrituration produces a setting expansion above the upper limit of 13 microns per centimeter, which is allowed by the specification, while a slightly overtriturated amalgam will not expand up to the lower limit of 3 microns. The use of mechanical amalgamators and pneumatic or automatic condensers also reduces the expansion and generally produces an actual contraction of several microns.2 Undoubtedly, many amalgam restorations are being placed daily which do not expand between 3 and 13 microns per centimeter. Some investigators, however, have felt that slight contraction in the amalgam restoration might not be clinically significant and that the increased strength and better handling characteristics associated with a slightly overtriturated amalgam would actually be advantageous.3 In a previous investigation, 34 amalgam restorations were placed in the permanent teeth of child patients by a technic which produced a setting contraction of 2 to 4 microns.4 After a 3-year observation period, there was no definite clinical evidence of contraction and the fillings handled in this manner proved to be slightly superior in terms of roughness and tarnish. The results of this study indicated that a slight contraction or expansion is not clinically significant. Naturally, the tremendous expansion of several hundred microns caused from moisture contamination is quite readily evidenced in amalgam fillings, but the slight deviation induced by a modification of the mixing time might not be clinically important. It should be pointed out that although the dimensional change is generally expressed in terms of microns per centimeter, the actual change across a typical restoration is much less since the width is generally less than 0.5 cm. It was felt that these previous results4 should be exaggerated by the use of a special composition alloy. Since most present popular alloys will not contract more than 10 microns, even with prolonged trituration, a 32 per cent tin alloy was compounded by Baker and Company for use in this study.* The technic for mixing and condensing this alloy was standardized in the laboratory
Probing the molecular basis of factor Xa specificity by mutagenesis of the serpin, antithrombin.

Abstract The molecular basis of the substrate and inhibitor specificity of factor Xa, the serine proteinase of the prothrombinase complex, was investigated by constructing two mutants of human antithrombin (HAT) in which the reactive site loop of the serpin from the P4–P4′ site was replaced with the corresponding residues of the two factor Xa cleavage sites in prothrombin (HAT/Proth-1 and HAT/Proth-2). These mutants together with prethrombin-2, the smallest zymogen form of thrombin containing only the second factor Xa cleavage site, were expressed in mammalian cells, purified to homogeneity and characterized in kinetic reactions with factor Xa in both the absence and presence of cofactors; factor Va, high affinity heparin and pentasaccharide fragment of heparin. HAT/Proth-1 inactivated factor Xa ∼3–4-fold better than HAT/Proth-2 in either the absence or presence of heparin cofactors. In the absence of a cofactor, factor Xa reacted with the HAT/Proth-2 and prethrombin-2 with similar second-order rate constants (∼2–3×102 M−1 s−1). Pentasaccharide catalyzed the inactivation rate of factor Xa by the HAT mutants 300–500-fold. A similar 104–105-fold enhancement in the reactivity of factor Xa with prethrombin-2 and the HAT mutants was observed in the presence of the cofactors Va and heparin, respectively. Factor Va did not influence the reactivity of factor Xa with either one of the HAT mutants. These results suggest that (1) in the absence of a cofactor, the P4–P4′ residues of HAT and prethrombin-2 primarily determine the specificity reactions with factor Xa, (2) factor Va binding to factor Xa is not associated with allosteric changes in the catalytic pocket of enzyme that would involve interactions with the P4–P4′ binding sites, and (3) similar to allosteric activation of HAT by heparin, a role for factor Va in the prothrombinase complex may involve rearrangement of the residues surrounding the scissile bond of the substrate to facilitate its optimal docking into the catalytic pocket of factor Xa.
Desorption rate isotherms in flash desorption analysis

Abstract In most flash desorption and temperature programmed desorption experiments only a small fraction of the data obtained is used in the kinetic analysis. A technique which utilizes more of the desorption data from a series of desorption curves obtained at different initial surface coverages is discussed. A number of desorption rate isotherms can be obtained by measuring desorption rates and coverages at selected temperatures in the desorption range. Each isotherm is a plot of ln (rate) versus ln (coverage) measured at a given temperature and its slope corresponds to the order of the desorption. From a series of desorption rate isotherms, plots of ln (rate) against 1 T can be obtained; the activation energy as a function of coverage can be obtained from the slopes of these plots. The success of the method for assisting in distinguishing between simple first-order desorption, first-order desorption with a coverage dependent activation energy and second-order desorption is illustrated. Theoretical calculations show the technique is very sensitive for distinguishing desorptions with coverage dependent activation energy. Analysis by desorption rate isotherms requires few assumptions, is easy to apply and can be used to determine kinetic parameters for both unsupported and supported catalysis.
Comparison Of Imaging Characteristics Of Digital Subtraction Angiography Utilizing Geometrical Magnification And Electro-Optical Magnification Techniques

The resolution characteristics of a digital subtraction angiography (DSA) system have been evaluated under two different magnification techniques, namely, the geometrical magnification technique and the electro-optical magnification technique. It has been found that the DSA system resolution is less dependent on the focal spot size [or modulation transfer function (MTF)] than that of routine radiographic angiographic studies. The evaluation results have been utilized to reestablish the DSA examination procedure.
Responses of cats to stimulation of the pulvinar complex: a behavioral and anatomical study.

Abstract In 14 cats there was a total of 23 bipolar stimulating electrodes successfully implanted in the pulvinar (Pul) complex. An aversive response to ipsilateral intracranial stimulation (ICS) beginning with 0.25 mA occurred in all cases and the majority of cats learned to escape the painful stimulus delivered on at least one side by crossing a shuttle box barrier. After this behavior was well established, lesions were made ipsilaterally through the same electrodes. In the postlesion trials the animals no longer responded to the ICS at currents less than 100% above the prelesion intensities. Upon completion of the postlesion trials, the nonlesion side was subjected to ICS, and never showed a nociceptive block due to the contralateral lesion. Then the animal received a second similar lesion through the electrode and was again subjected to a postlesion trial series. In eight cases an auditory negative reinforcer was introduced prior to the noxious ICS, and when associated with avoidance this preferential response was retained after the lesions. Not infrequently the primary pain responses were expressed as, or associated with, affective (savage) behavior, ocular, or other extrapyramidal motor responses. Histological evaluation showed an essentially equal distribution of the electrode tips in the medial, lateral, and inferior pulvinar nuclei, suprageniculate nucleus, and two in the magnocellular part of the medial geniculate body. In brains where the deOlmos-Ingram silver stain was used to trace axonal degeneration, there were always heavy axonal and terminal projections to the reticular nucleus. The fibers then continued through the internal capsule to spread and end in the medial suprasylvian and ectosylvian gyri. Other significant subcortical projections to the pretectal region, central gray, nucleus centromedianus, and the zona incerta were observed.
Evaluating the Influence of Environment on Virus Capsid Assembly Pathways through Stochastic Simulation

Understanding the unique biochemical and physical differences between typical in vitro experimental systems and the in vivo environment of a living cell is a question of great importance in building and interpreting reliable models of complex reaction systems. Virus capsids make an excellent model system for such questions because they tend to have few components, making them amenable to in vitro and modeling studies, yet their assembly can be described by enormously complex networks of possible reactions that cannot be resolved by any current experimental technology. We have previously attempted to bridge the gap between the complexity of the system and the limitations of data for tracking detailed assembly pathways using simulation-based model inference, learning kinetic parameters of coarse-grained rule models by fitting simulations to light scattering data from in vitro capsid assembly systems. Here, we describe extensions of that work to attempt to understand the influence of specific features of the cellular environment, individually or in concert, on assembly pathway selection. We specifically focus on the effects of macromolecular crowding and nucleic acid on capsid assembly, using coarse-grained biophysical models to adjust rate parameters learned from the in vitro system and suggest how these adjustments to fine-scale interactions may alter high-level pathway selection. Results from a series of virus capsid models suggest surprisingly complex and often counterintuitive mechanisms by which crowding or nucleic acids can alternately promote or inhibit assembly for different virus and assembly conditions.
The Effect of Many-Body Interactions on the Sedimentation of Monodisperse Particle Dispersions

Abstract An experimental investigation was made of the sedimentation rate of low-charged monodisperse silica and polystyrene latex particle dispersions as a function of the particle volume fraction. It was found that the normalized sedimentation velocityU/U0, corrected for the effect of the two-body hydrodynamic interaction, increases with the particle volume fraction, which indicates that the degree of particle aggregation inside the dispersions increases with the particle volume fraction. This phenomenon results from attractive many-body hydrodynamic interactions between colloidal particles. It is reported for the first time that the many-body hydrodynamic interaction becomes important at the particle concentration of 6.5 vol% in monodisperse dispersions, and the many-body thermodynamic interaction is negligible at a low particle concentration, i.e., less than 15 vol%. The effect of many-body hydrodynamic interaction on the particle microstructure was also experimentally examined by using a nondestructive Kossel diffraction technique based on the principle of back-light scattering. It was found that the particle packing structure inside the dispersion initially becomes more ordered with the increase of the particle volume fraction. However, there is less increase in the particle ordering structure after 6 vol%. Furthermore, after the particle concentration reaches 10 vol%, the particle packing structure decreases to a value lower than that of 6 vol% due to the increased particle aggregation, as found in the sedimentation experiments. Predictions of a statistical thermodynamic model were compared with the experimental data on structure factors. It is found that particle dimerization occurs around 10 vol%, which agrees with the sedimentation results.
Interference not mediated by Interferon

AUTOINTERFERENCE or autoinhibition is the phenomenon in which reduced multiplication of a virus results when a host is inoculated with a high concentration of virus. It has often been encountered in tissue culture cells with animal viruses. Members of the myxoviruses and arboviruses groups provide many examples1–4. These viruses can also induce interferon in the cells they infect. Interferon can be demonstrated in undiluted or low dilutions of culture fluids infected with virus used as inocula. Autointerference, therefore, has usually been attributed to the presence of interferon carried along with the inoculum. The present communication deals with an example of autointerference which results from the infection of chick embryo (CE) cells by Western equine encephalomyelitis (WEE) virus. The results showed that interferon was not involved in this instance.
Reduced viability, fertility and fecundity in mice lacking the cajal body marker protein, coilin.

Background Coilin is the signature protein of the Cajal body, a conserved nuclear organelle involved in multiple aspects of small ribonucleoprotein (RNP) biogenesis. Coilin is required for Cajal body homeostasis in both plants and animals. Mice lacking coilin are viable when the mutation is crossed to an outbred strain but only partially viable when crossed to inbred lines. Methodology/Principal Findings In order to clarify this issue, we backcrossed the coilin deletion onto the C57BL6/J background for ten generations and then investigated the consequences of coilin removal on overall viability and reproductive success. We conclude that semi-lethal phenotype observed in mixed-background crosses is due to loss of the Coilin gene (or a very tightly-linked locus). Interestingly, coilin knockout embryos die relatively late in gestation, between E13.5 and birth. We show that the maternal contribution of coilin is not important for organismal viability. Importantly, coilin knockout mice display significant fertility and fecundity defects. Mutant males that escape the embryonic lethality display reduced testis size, however, both males and females contribute to the observed reduction in reproductive fitness. Conclusions/Significance The evolutionary conservation of coilin from plants to animals suggests that the protein plays an important role, perhaps coordinating the activities of various RNA-processing machineries. Our observations are consistent with the idea that coilin functions to ensure robust organismal development, especially during periods of rapid growth.
Binding of benzo(a)pyrene to hepatic cytosolic protein enhances its microsomal oxidation

Abstract Sephadex G-100 gel permeation chromatography of rat liver cytosol saturated with 14 C-benzo(a)pyrene (BP) resulted in two peaks of protein bound radioactivity. Glutathione-S-transferase (GST) activity (towards 1-chloro 2,4-dinitrobenzene as substrate) was eluted as a single major peak which coincided with one peak of protein bound BP. Oxidation of protein bound BP (GST rich fractions) by microsomes from control or 3-methylcholanthrene treated rats was significantly enhanced as compared to ethanol suspended BP. The formation of oxidized products from the protein-bound BP was dependent on incubation time and microsomal protein concentration, required NADPH and was inhibited by monooxygenase inhibitors α-napthoflavone, 1-benzylimidazole, metyrapone and SKF 525A. Coemergence of BP binding-protein with GST suggests that the soluble protein could be one of the glutathione-S-transferases.
Growth hormone-releasing hexapeptide elevates intracellular calcium in rat somatotropes by two mechanisms.

The actions of GH-releasing hexapeptide (His-D-Trp-Ala-Trp-D-Phe-Lys-NH2 or GHRP-6) on single rat somatotropes were studied using whole cell patch clamp electrophysiology and indo-1 Ca2+ photometry. GHRP-6 elevated intracellular free Ca2+ ([Ca2+]i) in two phases: a rapid transient phase, followed by a persistent phase. Based on its insensitivity to treatments that block Ca2+ entry [removal of external Ca2+, addition of the dihydropyridine Ca2+ channel blocker nitrendipine (1 microM), and the hyperpolarizing action of zero external Na+ or 100 nM somatostatin], the transient elevation is the result of release of Ca2+ from intracellular stores. The half-maximal concentration for the peak [Ca2+]i rise during Ca2+ release was 49 nM GHRP-6. Prior treatment of cells with caffeine (10 mM) or ryanodine (50 microM) abolished or partially occluded GHRP-6-induced Ca2+ release. Simultaneous measurement of [Ca2+]i and membrane current or potential revealed that the transient release of Ca2+ by GHRP-6 activates a voltag...
Author's addendum to “some involutory similarities”

After submitting that paper {Linear and Multilinear Algebra 3 (1975), 19–23), the author noticed that two earlier proofs, substantially different from his, had appeared for (essentially) Theorem 2:
Digital calculation of network impedances

THE OPERATION of an electrical network may be defined by means of driving-point and transfer impedances. According to the American Standard Definitions of Electrical Terms, the driving-point impedance at any pair of terminals of a network is the ratio of an applied potential difference to the resultant current at these terminals, all terminals being terminated in any specified manner. Similarly, the transfer impedance between any two pairs of terminals of a network is the ratio of a potential difference applied at one pair of terminals to the resultant current at the other pair of terminals, all terminals being terminated in any specified manner.
Statistics of multiple particle breakage

A method for generating theoretical breakage distribution functions for multiple particle breakage is presented. It starts with the joint probability function that accounts for all the child particles; it is then reduced to the marginal probability function commonly used in the breakage equation. This method is flexible enough to allow the user to choose the number of child particles and the functional form to be used. The method is demonstrated with both product and summation functions with a power-law form. To facilitate the use of these theoretical functions for statistical analyses, a companion discretized breakage equation is developed. The new equation guarantees the conservation of mass and correct prediction of the total number of particles despite discretization. It is easy to use because it is a set of ordinary differential equations and applicable to both equal-size and geometric-size intervals. Simulation results show that different breakage distribution functions coupled with different breakage rates can produce almost indistinguishable particle-size distributions, signifying the need for further work in this area.
A defence of liberal democracy for Africa

The article counters criticism of liberal democracy in Africa, and proposes that liberal democracy is the best way to address Africa's political and economic problems. It contends that recent democratisation efforts have failed due to the conceptual confusion between majoritarianism and constitutional democracy, where only the latter can ensure freedom and security on the continent. The article goes on to argue for the primacy of individual rights over collective or group rights as the latter increase government control over people's lives. Despotic leaders often misuse group rights and repress the groups that empowered them. Finally, the article rejects as empirically and morally false the view that economic development should be a precondition for democratisation, and that African culture is in some way inimical to liberal democracy.
Status of HgCdTe MBE technology for IRFPA

HgCdTe MBE technology is becoming a mature growth technology for focal plane array applications. Device quality materials have been growth with alloy compositions required for SWIR to VLWIR applications. X-ray characterization results indicate that the epilayers exhibit FWHM of about 25 arc-sec, which is indicative of high quality materials. In addition to x-ray data, the observation of low defect density (EPD < 2 X 105/cm2), long minority carrier lifetime (t equals 1 micro-second for x equals 0.23, n equals 2 X 1015/cm3), and efficient IR photoluminescence, all attest to the device quality of HgCdTe epilayers grown by MBE. The breakthroughs to achieve In(n-type) and As(p-type) doping in-situ provide greater flexibility for fabricating advanced heterojunction devices. High-performance IR devices that use HgCdTe MBE materials are demonstrated. The additional development of drying etching and passivation in an ultrahigh vacuum environment coupled with an MBE growth system should lead to cost-effective and flexible manufacturing of devices for military and commercial applications.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.