cssi/SciSciGPT-SciSciNet huggingface dataset:
Rotational position of a 5-methylcytosine-containing cyclobutane pyrimidine dimer in a nucleosome greatly affects its deamination rate.

C to T mutation hotspots in skin cancers occur primarily at methylated CpG sites that coincide with sites of UV-induced cyclobutane pyrimidine dimer (CPD) formation. These mutations are proposed to arise from the insertion of A by DNA polymerase η opposite the T that results from deamination of the methylC (mC) within the CPD. Although the frequency of CPD formation and repair is modestly modulated by its rotational position within a nucleosome, the effect of position on the rate of mC deamination in a CPD has not been previously studied. We now report that deamination of a TmC CPD whose sugar phosphate backbone is positioned against the histone core surface decreases by a factor of 4.7, whereas that of a TmC CPD positioned away from the surface increases by a factor of 8.9 when compared with unbound DNA. Because the mCs undergoing deamination are in similar steric environments, the difference in rate appears to be a consequence of a difference in the flexibility and compression of the two sites due to DNA bending. Considering that formation of the CPD positioned away from the surface is also enhanced by a factor of two, a TmCG site in this position might be expected to have up to an 84-fold higher probability of resulting in a UV-induced mC to T mutation than one positioned against the surface. These results indicate that rotational position may play an important role in the formation of UV-induced C to T mutation hotspots, as well as in the mutagenic mechanism of other DNA lesions.
Molecular, metabolic and immune evidence suggests that systemic autoimmune disease is antigen-mediated

Patients with systemic lupus erythematosus generate a sustained immune response against self. The tools of modern molecular biology have been applied to cell activities and elements/signals of the immune system, but a structural or regulatory defect has not been found. When deoxyribonucleic acids for autoantibodies were cloned and sequenced, they were like other autoantibody DNA sequences; when genetic materials for autoantibodies were inserted into transgenic mice, cells secreting the antibodies were subject to normal control mechanisms and eliminated. A failure to clear self-reactive antibody producing thymocytes has not been demonstrated in human systemic lupus erythematosus. Molecular analyses of the efferent side of the immune response have been largely normal in systemic lupus erythematosus. The structure of autoantibodies suggests that they have been generated by selection pressures and the presence of endogenous antigens. If the immune system attack on self was secondary, structural changes and metabolic reactions capable of generating antigens should be found in systemic lupus erythematosus cells. Structural changes have been found in deoxyribonucleic acid from phytohaemagglutinin-stimulated systemic lupus erythematosus lymphocytes in the form of S1 nuclease-sensitive deoxyribonucleic acid breaks. Altered cellular macromolecules could result from endogenous metabolic processes, particularly oxygen free radicals and arachidonic acid metabolites. Excess free-radical species, generating positive nitroblue tetrazolium-reacting material and positive chemiluminescence, have been found in most but not all phytohaemagglutinin-stimulated lupus lymphocyte samples. If endogenous metabolic processes act on endogenous deoxyribonucleic acid, endogenous cell DNA breakdown may lead to low molecular weight deoxyribonucleic acids and deoxyribonucleic acid/immune complexes in systemic lupus erythematosus sera that are potentially immunogenic. These combined findings suggest that the exaggerated immune responses of systemic lupus erythematosus may be a normal response to protect the host from a perceived antigenic threat.
Opportunistic media access for multirate ad hoc networks

The IEEE 802.11 wireless media access standard supports multiple data rates at the physical layer. Moreover, various auto rate adaptation mechanisms at the medium access layer have been proposed to utilize this multi-rate capability by automatically adapting the transmission rate to best match the channel conditions. In this paper, we introduce the Opportunistic Auto Rate (OAR) protocol to better exploit durations of high-quality channels conditions. The key mechanism of the OAR protocol is to opportunistically send multiple back-to-back data packets whenever the channel quality is good. As channel coherence times typically exceed multiple packet transmission times for both mobile and non-mobile users, OAR achieves significant throughput gains as compared to state-of-the-art auto-rate adaptation mechanisms. Moreover, over longer time scales, OAR ensures that all nodes are granted channel access for the same time-shares as achieved by single-rate IEEE 802.11. We describe mechanisms to implement OAR on top of any existing auto-rate adaptation scheme in a nearly IEEE 802.11 compliant manner. We also analytically study OAR and characterize the gains in throughput as a function of the channel conditions. Finally, we perform an extensive set of ns-2 simulations to study the impact of such factors as node velocity, channel conditions, and topology on the throughput of OAR.
Rapid photo-oxidation of Mn(II) mediated by humic substances

Abstract The oxidation of Mn(II) by O2 to Mn(III) or Mn(IV) is thermodynamically favored under the pH and pO2 conditions present in most near surface waters, but the kinetics of this reaction are extremely slow. This work investigated whether reactive oxygen species, produced through illumination of humic substances, could oxidize Mn at an environmentally relavent rate. The simulated sunlight illumination of a solution containing 200 μM Mn(II) and 5 mg/L Aldrich humic acid buffered at pH 8.1 produced ∼19 μM of oxidized Mn (MnOx where x is between one and two) after 45 minutes. The major oxidants reponsible for this reaction appear to be photoproduced superoxide radical anion, O2−, and singlet molecular oxygen, 1O2. The dependencies of MnOx formation on Mn(II), humic acid, and H+ concentration were characterized. A kinetic model based largely on published rate constants was established and fit to the experimental data. As expected, analysis of the model indicates that the key reaction rate controlling MnOx production is the rate of decomposition of a MnO2+ complex formed from the reaction of Mn(II) with O2−. This rate is strongly dependent on the Mn(II) complexing ligands in solution. The MnOx production in the seawater sample taken from Bodega Bay, USA and spiked with 200 μM Mn(II) was well reproduced by the model. Extrapolations from the model imply that Mn photo-oxidation should be a significant reaction in typical surface seawaters. Calculated rates, 5.8 to 55 pM h−1, are comparable to reported rates of biological Mn oxidation, 0.07 to 89 pM h−1. Four fresh water samples that were spiked with 200 μM Mn(II) also showed significant MnOx production. Based on these results, it appears that Mn photo-oxidation could constitute a significant, and apparently unrecognized geochemical pathway in natural waters.
Ion induced promotion of activity enhancement of mesoporous manganese oxides for aerobic oxidation reactions

Abstract Inverse micelle templated mesoporous manganese oxide (University of Connecticut mesoporous material, UCT-1) and ion promoted mesoporous manganese oxides (UCT-18-X, X = Mg2+, Ca2+, K+, Na+ and Cs+) having trace amount of alkali metal ions as promoters with tunable porosity and crystallinity were synthesized. The synthesis was based on the use of inverse micelles as soft templates and unique NOx chemistry as established for recently discovered UCT materials. The materials were tested for selective aerobic alcohol oxidation and the catalytic activity followed the order of UCT-1 90% conversion and 90% selectivity for the acid and 9% selectivity for the ester.
Am phases in the matrix of a U–Pu–Zr alloy with Np, Am, and rare-earth elements ☆

Phases and microstructures in the matrix of an as-cast U-Pu-Zr alloy with 3 wt% Am, 2% Np, and 8% rare-earth elements were characterized by scanning and transmission electron microscopy. The matrix consists primarily of two phases, both of which contain Am: ζ-(U, Np, Pu, Am) (~70 at% U, 5% Np, 14% Pu, 1% Am, and 10% Zr) and δ-(U, Np, Pu, Am)Zr2 (~25% U, 2% Np, 10-15% Pu, 1-2% Am, and 55-60 at% Zr). These phases are similar to those in U-Pu-Zr alloys, although the Zr content in ζ-(U, Np, Pu, Am) is higher than that in ζ-(U, Pu) and the Zr content in δ-(U, Np, Pu, Am)Zr2 is lower than that in δ-UZr2. Nanocrystalline actinide oxides with structures similar to UO2 occurred in some areas, but may have formed by reactions with the atmosphere during sample handling. Planar features consisting of a central zone of ζ-(U, Np, Pu, Am) bracketed by zones of δ-(U, Np, Pu, Am)Zr2 bound irregular polygons ranging in size from a few micrometers to a few tens of micrometers across. The rest of the matrix consists of elongated domains of ζ-(U, Np, Pu, Am) and δ-(U, Np, Pu, Am)Zr2. Each of these domains is amore » few tens of nanometers across and a few hundred nanometers long. The domains display strong preferred orientations involving areas a few hundred nanometers to a few micrometers across.« less
Effects of 8-Gy radiation on the microcirculation of muscle flaps in the rat

Combination of radical excision and radiation has been used as a treatment modality for cancer patients. As a result, in reconstructive surgery there is often a need to harvest flaps in the vicinity of previously irradiated tissues. Radiation has been shown to cause progressive injury to the macrocirculation and microcirculation, often jeopardizing flap survival. The purpose of this study was to examine whether radiation significantly affects the sequence of leukocyte-endothelial interactions or the hemodynamics of the muscle flap in both acute and chronic situations. Male Sprague-Dawley rats (n = 42) were divided into seven groups of six rats each. Rats in group I were not irradiated. Groups II through VII received 8-Gy radiation to the right groin and scrotum. Groups II, III, and IV were examined at 4, 24 and 72 hours, respectively, and groups V, VI, and VII were examined at 1, 2 and 12 weeks. For intravital microscopy, the cremaster muscle was dissected on its neurovascular pedicle. Vessel diameters and red blood cell velocities were measured in the central cremasteric branches and branch arterioles. Capillary perfusion was evaluated in 27 visual fields of each flap. Leukocyteendothelial interactions were evaluated by numbers of rolling, adhering, and transmigrating leukocytes in postcapillary venules. In the same postcapillary venule, we measured the endothelial edema index (constriction index). The hemodynamics of irradiated flaps did not differ significantly from those of controls. Diameter and red blood cell velocity were increased in the first- and secondorder arterioles and were highest at 72 hours and 1 week. After irradiation, third-order arterioles were constricted. Radiation reduced capillary perfusion by 4.3 percent. None of the differences were statistically significant. Neither leukocyte behavior nor the constriction indices differed among the groups. In conclusion, low-dose radiation of 8 Gy does not affect hemodynamics or leukocyteendothelial interactions of muscle flaps in the rat. Muscle tissue with intact microvasculature can be harvested for reconstructive procedures after low-dose radiation. (Plast. Reconstr. Surg. 104: 1372, 1999.)
The Social Context of Commemoration: A Study in Collective Memory

Using as data the events and persons commemorated in the United States Capitol, this inquiry demonstrates how the significance of historical events changes from one generation to the next according to a changing infrastructure of societal problems and needs. Before the Civil War, two historical periods, colonization and revolution, produced the only events and heroes on whose commemoration a deeply divided Congress could agree. Once the unity of the nation was brought about by force of arms, the pattern of commemoration changed. Belated recognition was given to the events and heroes of the postrevolutionary period and to outstanding regional, as opposed to national, figures. The commemoration of office incumbency was superimposed on that of extraordinary military and political achievement, thus celebrating the stable institutional structures into which the charisma of the nation's founders finally became routinized. These and other changes in the Capitol's commemorative symbolism reflect the Civil War's solution to the antebellum problems of integration and pattern maintenance. The bearing of these findings on different theories of collective memory is discussed.
Methods for mapping of interaction networks involving membrane proteins

Nearly one-third of all genes in various organisms encode membrane-associated proteins that participate in numerous protein-protein interactions important to the processes of life. However, membrane protein interactions pose significant challenges due to the need to solubilize membranes without disrupting protein-protein interactions. Traditionally, analysis of isolated protein complexes by high-resolution 2D gel electrophoresis has been the main method used to obtain an overall picture of proteome constituents and interactions. However, this method is time consuming, labor intensive, detects only abundant proteins and is limited with respect to the coverage required to elucidate large interaction networks. In this review, we discuss the application of various methods to elucidate interactions involving membrane proteins. These techniques include methods for the direct isolation of single complexes or interactors as well as methods for characterization of entire subcellular and cellular interactomes.
An Assessment of Nurses’ Knowledge of Botulism

Objective To assess nurses’ knowledge of botulism, a Centers for Disease Control Category A bioterrorism agent, one case of which constitutes an emergency. Design The study utilized survey research. Sample The cluster sample included 1,414 registered nurses. Measure The survey gathered demographic data and nurses’ knowledge of the background, manifestation and management of botulism. Results The mean percentage of correct answers for the sample was 25.95%, with a standard deviation (SD) of ±19.89%. Only 90 (6.3%) achieved 60% or more correct. Educational preparation, experience, specialty/area of practice and whether nurses had a class in disaster medicine were also examined and although differences were noted, none of these factors accounted for a score of 60% or above. Conclusions The results of this study indicate the need for an assessment of the current education nurses receive about botulism.
Starch grain morphology of the seagrasses Halodule wrightii, Ruppia maritima, Syringodium filiforme, and Thalassia testudinum

Abstract Starch grains are a ubiquitous component of plants that have been used in tandem with phytoliths, pollen, and macrofossils to reconstruct past floral diversity. This tool has yet to be fully explored for aquatic plants, specifically seagrasses, which lack phytoliths and are rarely preserved as macrofossils or pollen. If starch grains in seagrasses are morphologically distinct, this method has the potential to improve seagrass identification in the fossil record in such cases where its starch is preserved (e.g. scratches and occlusal surfaces of tooth enamel from seagrass consumers). The goals of this study were twofold: (1) to determine if starch is present in seagrass material and (2) to assess how starch grain morphology differs between different seagrasses. This study focused on four abundant and ecologically distinct seagrasses from the Caribbean: Halodule wrightii , Ruppia maritima , Syringodium filiforme , and Thalassia testudinum . Starch grains were observed in all species except S. filiforme . Grains from H. wrightii are typically observed in side-on orientation, are sub-round to angular, and are fairly small (3-19 μm, end-on). Grains of R. maritima are small spherical grains (4–8 μm) that have a centric hilum and a straight extinction cross with a median angle between the arms of 90°. Grains from T. testudinum are large (9–31 μm, end-on), conical in side-on and round/sub-round in end-on orientation, have a slightly eccentric hilum with an obvious particle, and prominent lamellae. Visual assessment and comparative statistics demonstrate that the morphology of starch grains from T. testudinum , R. maritima , and H. wrightii are significantly different. With more extensive research, there is potential for the positive identification of starch grains from an unknown seagrass. The ability to identify seagrass from starch grains could facilitate the identification of seagrasses in the fossil record and supply information on seagrass evolution and distribution, climate effects on seagrass distribution, and the diets of seagrass consumers.
Balancing of battery networks via constrained optimal control

This paper defines two control problems: the capacity maximization and the battery balancing problems. In the first part, we compare the two problems by analyzing properties of their solutions. In the second part, two algorithms are presented for solving the capacity maximization and battery balancing problems respectively. These algorithms are based on constrained optimization techniques. We prove asymptotic convergence of both algorithms and present a numerical example.
Effect of Cu–Al2O3 nanocomposite coating on flow boiling performance of a microchannel

Abstract Convective heat transfer performance of Cu–Al2O3 nanocomposite coated surface has been investigated experimentally for its potential use in heat transfer equipment operating in corrosive environment. Experimental studies were carried out in a bottom surface heated single microchannel of 672 μm hydraulic diameter using de-ionized (DI) water as the coolant. Thin nanocomposite coating was developed on the bottom surface of the microchannel using electrocodeposition technique. Both single-phase and two-phase convective heat transfer experiments were performed at different mass flux. The results from microchannel with bare Cu surface are used as the baseline data. Cu–Al2O3 nanocomposite coating has been found to enhance single-phase heat transfer rate marginally, whereas in the two-phase regime, the enhancement was ∼30% to ∼120% depending on the flow rate and surface temperature with an additional pressure drop penalty of less than ∼15%. CHF also improves for the coated surface by ∼35% to ∼55%.
Expression and stability of soybean resistance to agromyzid beanflies

Plants express evolutionary adaptations in response to overall environmental stresses (selection pressures), of which insect infestation usually represents only a minor component. The majority of insect-host plant relationships involves adaptations of insect species to existing plants. Over time, plants have evolved a variety of physical and chemical defence mechanisms against environmental stresses. Only some of these are active against insects, and then not against all species. Plants rarely seem to evolve defences specifically against insects. Parameters of plant resistance to parasites are classified as constitutive or inducible. Soybean resistance to agromyzid stem-miners involves both constitutive and inducible components. Expression of such resistance parameters involves controls ranging from single genes (e.g. for trichome traits) to various combinations of genes (e.g. for the metabolic pathway for phenyl-propanoids). Environmental stresses (e.g. high illumination) especially affect the expression of resistance parameters which involve dynamic metabolic pathways. Soybean (Glycine soja) resistance to beanflies is an example of ‘horizontal’ resistance. Thus, the expected stability is long-term. Such stability is attributable to its major parameters being fundamental components of the soybean's primary and secondary growth and differentiation. These kinds of parameters are major products of the soybean's successful evolutionary experience at survival.
Computer bulletin boards: The computerized version of the old-fashioned neighborhood corkboard

The author explains what bulletin boards are and describes what's available on them and how to use them profitably.
Self-assembly of amphiphilic block copolymers in ternary solvent mixtures: Lyotropic liquid crystalline phase behavior and structure

The effects of the simultaneous addition of two organic solvents (glycerol and ethanol) on the lyotropic liquid crystalline (LLC) phase behavior and structure formed by PEO–PPO–PEO amphiphilic block copolymers in water are examined. Glycerol and ethanol have been selected because of their opposite effect: structure promoting and structure dissolving, respectively. Lattice parameters of Pluronic P105 (EO 37 PO 58 EO 37 ) and F127 (EO 100 PO 70 EO 100 ) LLC samples in the presence of any type and amount of E + G solvents decrease with increasing volume fraction of the PPO-rich domains. Lattice parameters for the two block copolymers fall on the same line when normalized with the square root of polymer molecular weight, suggesting weak block segregation.
Some notes on the distribution of alkaloids in the plant kingdom.

In the search for a natural system of classification, various secondary plant constituents have been considered to have taxonomic significance. Among such substances are the alkaloids. I would like to offer some brief comments and observations on their distribution in the plant kingdom based on a recent review of the literature through mid-1968. No simple, universally accepted definition of thbe word "alkaloid" exists. Traditionally these compounds have been considered as nitrogenous bases (some are not basic at all) found in plants (some are found in animals), of complex chemical structure (some are quite simple), usually (but certainly not always) producing a marked physiological response in animal systems. Thus they are often associated with the toxicity or the medicinal usefulness of the plants or animals from which they are obtained. Following the isolation of morphine from opium in the early 19th Century, the chemical nature of many of the alkaloids was established and several of them, either as pure compounds or as somewhat standardized mixtures, replaced the plants and extracts from which they were derived and found their places in medicine as useful drugs. About the time of World War I, interest in these substances waned in favor of synthetic medicinals, which a growing chemical industry seemed able to produce at will. Nonetheless, research on these interesting plant substances continued and, in part because natural materials served as models for new and possibly improved synthetic drugs, many novel alkaloids were isolated and charactertized. This is particularly true for the past decade, the "post-reserpine era,"
Flame guncreting of converter linings

At the Zhdanov Metallurgical Factory for fusing sections of local burnouts in the linings of 130 ton oxygen converters use is now being made of flame guncreting. The guncreting extends the converter campaign by 20–135 heats with a guncrete body consumption of 0.5–1.5 kg/ton of steel.
The effect of clouds on air showers observation from space

Abstract Issues relating to extensive air showers observation by a space-borne fluorescence detector and the effects of clouds on the observations are investigated using Monte Carlo simulation. The simulations assume the presence of clouds with varying altitudes and optical depths. Simulated events are reconstructed assuming a cloud-free atmosphere. While it is anticipated that auxiliary instruments, such as LIDAR (light detection and ranging), will be employed to measure the atmospheric conditions during actual observation, it is still possible that these instruments may fail to recognize the presence of a cloud in a particular shower observation. The purpose of this study is to investigate the effects on the reconstructed shower parameters in such cases. Reconstruction results are shown for both monocular and stereo detectors and for the two limiting cases of optically thin, and optically thick clouds.
Time-resolved X-ray study of poly(aryl ether ether ketone) crystallization and melting behaviour: 1. Crystallization

Time-resolved simultaneous small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD) experiments using synchrotron radiation were made in order to study the isothermal crystallization behaviour of poly(aryl ether ether ketone) (PEEK). Two types of long period (LB and LMC), the scattering invariant Q, and the linear degree of crystallinity within the lamellar stacks xCL were estimated from the Lorentz-corrected plot and the correlation function. As a result, the average lamellar thickness lC was calculated as the product of LMC and xCL during crystallization at temperatures of 230–310°C. The bulk degree of crystallinity (by weight), ψC, was determined by WAXD. It was found that both long periods decreased, Q increased and lC remained approximately constant with time. The decrease in the long period was explained by the lamellar insertion within the lamellar stacks, whereas the increase in Q was attributed to the increase in the bulk-volume degree of crystallinity xC, rather than xCL. In addition, the values of the long period and of Q were found to increase with temperature as a result of the thicker lamellae. Finally, our results support the model of two populations in lamellar thickness, namely the primary lamellae which are developed first in bundle-like stacks, and the narrower, secondary lamellae (as a small fraction) that are inserted later between the primary lamellae under various spatial restrictions.
Alcohol-Induced Stimulation and Sedation: Relation to Physical Aggression

The relation between the stimulating and the sedating effects of acute alcohol consumption on human physical aggression was examined. Sixty male social drinkers were assigned to either an alcohol or a sober group. Aggression was measured using a modified version of S. Taylor's (1967) aggression paradigm, in which electric shocks are received from and administered to a fictitious opponent during a competitive task. Aggression was operationalized as the intensity and the duration of the shocks selected. Stimulation and sedation were measured using a self-report inventory. Results demonstrated that stimulation was positively related to aggression, but only in the intoxicated state. Sedation was not related to aggression in either the intoxicated or the sober state.
The effects of hypoxia on pulmonary function and maximal rates of oxygen consumption in two anuran amphibians

1. The effects of ambient\(P_{O_2 } \) on the maximal rate of oxygen consumption, alveolar\(P_{O_2 } \) and alveolar ventilation rate were measured for two species of anuran amphibians during forced activity. The maximal rates of oxygen consumption were independent of ambient\(P_{O_2 } \) values as low as 80 Torr for bothBufo cognatus (1.5 ml O2 g−1 h−1) andRana pipiens (0.64 ml g−1 h−1), and were linearly proportional to ambient\(P_{O_2 } \) at less than 80 Torr. 2. The alveolar\(P_{O_2 } \) ofB. cognatus andR. pipiens during forced activity at a normal ambient\(P_{O_2 } \) was 125–135 Torr. Alveolar\(P_{O_2 } \) declined linearly for both species under hypoxic conditions. 3. The alveolar ventilation rate was calculated from maximal oxygen consumption rate and alveolar\(P_{O_2 } \) at various ambient\(P_{O_2 } \) values. The alveolar ventilation rate at 153 Torr was 32 ml min−1atpd forB. cognatus and 19 forR. pipiens during forced activity. Theatpd alveolar ventilation increased substantially at lowered ambient\(P_{O_2 } \), although thestpd alveolar ventilation declined markedly. The interspecific differences in maximal rates of oxygen consumption were correlated with the interspecific differences in alveolar ventilation rates. 4. The relationship between maximal rate of oxygen consumption and ambient\(P_{O_2 } \) forB. cognatus andR. pipiens indicates that ambient\(P_{O_2 } \) and pulmonary ventilation rates do not normally limit the maximal rates of respiratory gas exchange in anuran amphibians. The critical\(P_{O_2 } \) (80 Torr), below which the maximal rate of oxygen consumption declines, corresponds to an altitude of about 4500 m, and is less than the ambient\(P_{O_2 } \) encountered by terrestrial anuran amphibians in their natural environments.
Mechanisms of B-Cell Synapse Formation Predicted by Monte Carlo Simulation

The clustering of B-cell receptor (BCR) molecules and the formation of the protein segregation structure known as the “immunological synapse” at the contact region between B cells and antigen presenting cells appears to precede antigen (Ag) uptake by B cells. The mature B-cell synapse is characterized by a central cluster of BCR/Ag molecular complexes surrounded by a ring of LFA-1/ICAM-1 complexes. In this study, we investigate the biophysical mechanisms that drive immunological synapse formation in B cells by means of Monte Carlo simulation. Our approach simulates individual reaction and diffusion events on cell surfaces in a probabilistic manner with a clearly defined mapping between our model's probabilistic parameters and their physical equivalents. Our model incorporates the bivalent nature of the BCR as well as changes in membrane shape due to receptor-ligand binding. We find that differences in affinity and bond stiffness between BCR/Ag and LFA-1/ICAM-1 are sufficient to drive synapse formation in the absence of membrane deformation. When significant membrane deformation occurs as a result of receptor-ligand binding, our model predicts the affinity-dependent mechanism needs to be complemented by a BCR signaling-driven shift in LFA-1 affinity from low to high in order for synapses to form.
Fuel Optimality of Cruise

IN the paper by Schultz and Zagalsky, the solution characteristics for the minimum fuel-fixed range problem are determined for a number of different mathematical models of aircraft dynamics. Different results are obtained for different sets of equations. The energy state equations are shown to not allow a partial throttle, constant velocity, cruise solution; but because the velocity set is not convex, to have a "chattering" solution which provides the best performance but which may not be realizable with plecewise continuous maximum values of the controls. The equation set with throttle and flight path angle as controls was shown to allow a partial throttle cruise solution. This conclusion was shown to be invalid by Speyer by application of the Generalized Legendre-Clebsch condition. The following analysis shows that for a higher order set of equations which has lift and thrust as controls, the necessary condition for optimization including the Generalized Legendre-Clebsch condition are satisfied at the cruise point so that the partial throttle cruise condition is a candidate solution for the minimum fuel-fixed range problem.
International cooperation in science and technology with Japan, China and Chile

The U.S.-Japan Cooperative Program in Natural Resources (UJNR) has a general objective of promoting development and conservation of natural resources through cooperative activities. Forms of cooperation include joint research projects, such as deep-sea diving, and the reciprocal exchange of scientific information, technical data, specialists, study tours and research equipment. Technical documents are continually generated by various UJNR panel activities. The U.S.-People's Republic of China (PRC) Cooperation in the Field of Marine and Fishery Science and Technology has completed a joint Changjiang (Yangtze River) Estuary study and is beginning a joint study of interannual variability of tropical oceans and global atmosphere (TOGA) in the western Tropical Pacific Ocean. U.S.-Chile Cooperation is beginning. In addition to Chile's participation in TOGA, a notable 3-year project entitled Tsunami Hazard Reduction Utilizing System Technology (THRUST) is to establish a real-time tsunami warning system served by satellite communication. Hopefully a THRUST system will monitor the entire Pacific Rim when a Japanese stellite joins in to cover the western Pacific.
Phase I imaging study of Hodgkin's disease and non-Hodgkin's lymphomas with radiolabeled antibody to eosinophil peroxidase.

Hodgkin's disease and non-Hodgkin's lymphomas are both primary malignancies of the immune system. One of the unusual features of Hodgkin's disease tumors is the presence of numerous benign inflammatory cells, such as histiocytes, lymphocytes, plasma cells, and eosinophils (1). In many patients with Hodgkin's disease, the reactive inflammatory cells far outnumber the Reed-Sternberg cells and Hodgkin's cell variants, which are considered to be the neoplastic components of Hodgkin's disease. Certain non-Hodgkin's lymphomas (particularly those of T-cell derivation) also sometimes contain numerous benign reactive inflammatory cells.
Nitric Oxide Synthase (NOS3)–Mediated Cholinergic Modulation of Ca2+ Current in Adult Rabbit Atrioventricular Nodal Cells

We examined the role of endogenous NO in the autonomic regulation of atrioventricular (AV) nodal function by studying spontaneous action potentials (SAPs) and L-type Ca2+ current (ICa-L) in isolated single AV nodal cells from adult rabbit hearts. Both the perforated and the membrane-ruptured patch-clamp techniques in the whole-cell configuration were used under conditions known to alter NO production. Three NO donors, 3-morpholinosydnonimine (SIN-1, 0.1 mmol/L), S-nitroso-acetylcysteine (0.1 mmol/L), and sodium nitroprusside (0.1 mmol/L), suppressed the beta-adrenergic agonist isoproterenol (ISO, 1 mumol/L)-stimulated increase in ICa-L. SIN-1 also decreased the frequency and amplitude of SAPs. In cells in which ICa-L had been previously attenuated by the muscarinic agonist carbamylcholine (CCh, 1 mumol/L), SIN-1 had no additive effect. CCh activated an acetylcholine-sensitive outward K+ current (IK(ACh)) in AV nodal cells, in addition to the ICa-L inhibition. Intracellular dialysis with the NO synthase inhibitor N-monomethyl-L-arginine (L-NMMA, 0.5 mmol/L) blocked CCh-induced, but not SIN-1-induced, ICa.L attenuation. However, intracellular dialysis with methylene blue (20 mumol/L), which inhibits NO-mediated activation of guanylyl cyclase and cGMP production, blocked the effects of both CCh and SIN-1 on ICa-L. In these cells, neither L-NMMA nor methylene blue affected the CCh-activated IK(ACh). Direct application of cGMP (10 mumol/L) via internal dialysis significantly inhibited ISO-stimulated ICa-L. In AV nodal cells internally perfused with either a nonhydrolyzable cAMP analogue, 8-Br-cAMP (0.5 mmol/L), or a high concentration of cAMP (0.5 mmol/L), CCh did not inhibit, ICa-L but still activated IK(ACh). CCh-induced ICa-L attenuation could be abolished or quickly reversed by the nonselective phosphodiesterase (PDE) inhibitor 3-isobutyl-1-methylxanthine (20 mumol/L). However, CCh still significantly suppressed ISO-stimulated ICa-L after the cGMP-inhibited PDE isozyme (PDE3) had been selectively inhibited by milrinone (5 mumol/L). Immunohistochemical staining identified the presence of the endothelial constitutive NO synthase (ecNOS or NOS3) in both single AV nodal cells in vitro and in cryostat sections of AV nodal tissue in situ. These results demonstrate that endogenous NO is involved in the muscarinic cholinergic attenuation of ICa-L in AV nodal cell; the mechanism likely involves the cGMP-stimulated PDE.
Hair Dye Use and Risk of Adult Acute Leukemia

Certain chemicals in hair dyes are known animal carcinogens. Darker, more permanent, and earlier dye formulations may be more carcinogenic than other dye types. For 769 adult acute leukemia cases and 623 population-based controls in a US and Canadian case-control study in 1986-1989, the authors asked separately about use of permanent and nonpermanent (semipermanent and temporary) hair dye use. Use was reported by 45% of women and 6% of men. There was a modest positive association for ever use of permanent dyes (odds ratio = 1.5, 95% confidence interval: 1.0, 2.1), which was stronger for long duration (15 or more years) of use (odds ratio = 1.8, 95% confidence interval: 1.0, 3.1). The greatest odds ratio was for 15 or more years of using hair dyes up to six times per year (odds ratio = 2.4, 95% confidence interval: 1.0, 5.8); the corresponding odds ratio for use six or more times a year was lower, suggesting the possibility of misclassification of dye type among frequent users, since nonpermanent dyes tend to be used more frequently than permanent dyes. Nonpermanent dyes were not associated with risk. Long duration of permanent dye use may have a larger impact on the risk of adult acute leukemia and other hematopoietic cancers than prior epidemiologic data suggest.
The approximate oral toxicity in rats of selected household products

Abstract The acute, “screening,” oral toxicities of about 40 common household products purchased in neighborhood stores were determined in adult albino female rats. All products fell in toxicity classes 1, 2, or 3 as defined in Gleason et al. (1957), i.e., had lethal doses greater than 500 mg/kg. From the standpoint of acute oral toxicity, appropriate labeling is suggested for substances lethal in amounts of 500 mg/kg or less unless experience has demonstrated a negligible hazard; substances of lesser toxicity would remain unlabeled unless hazard was demonstrated.
A comparison of teacher immediacy in African‐American and Euro‐American college classrooms

Matched‐race perceptions of teacher immediacy of African‐American and Euro‐American college teachers were compared. African‐American (N = 77) and Euro‐American (N = 113) college students at matched‐race colleges completed versions of the teacher immediacy scale and indices of cognitive, affective, and behavioral learning. Consistent with the general hypothesis guiding the study, teacher immediacy scores were higher for the African‐American teachers than the Euro‐American teachers. Significant positive correlations between immediacy and measures of cognitive, affective, and behavioral learning were observed for both groups, but the correlations were significantly greater for the Euro‐Americans.
Long phase coherence time and number squeezing of two Bose-Einstein condensates on an atom chip.

We measure the relative phase of two Bose-Einstein condensates confined in a radio frequency induced double-well potential on an atom chip. We observe phase coherence between the separated condensates for times up to $\ensuremath{\sim}200\text{ }\text{ }\mathrm{ms}$ after splitting, a factor of 10 longer than the phase diffusion time expected for a coherent state for our experimental conditions. The enhanced coherence time is attributed to number squeezing of the initial state by a factor of 10. In addition, we demonstrate a rotationally sensitive (Sagnac) geometry for a guided atom interferometer by propagating the split condensates.
Dynamic effects on ignitability limits of solidpropellants subjected to radiative heating

The dynamic response of a solid propellant to a rapidly varying radiation flux comprises a problem representative of the general class of transient responses of heterogeneous flames to rapid disturbances. In the present study, the response of double-base propellants to roughly square-wave radiation pulses is examined. It is found that, when such pulses are used to ignite propellants, they may in some cases produce a flame which persists for whatever duration the pulse persists, but which extinguishes as soon as the pulse stops. This tendency to extinction upon deradiation is found to be lessened by increased pressure or increased time interval for reducing the flux to zero. This extinction response upon deradiation is not limited to the ignition situation; it is shown experimentally that a steadily burning propellant can be extinguished by a radiation pulse of appropriate magnitude, duration, and speed of cut-off. It is proposed that this dynamic extinction behavior results from an imbalance in the heat fluxes to and from the burning surface during deradiation. A mathematical model of this phenomenon, deriving from the nonsteady burning approach of Zeldovich, is solved and shown to predict quite well the same type of behavior as that found experimentally.
Use of a keystroke log file to evaluate an interactive computer system in a museum setting

Abstract Multimedia evaluation and evaluation of public space learning environments are complex processes. The typical challenges of public space design and implementation, such as the inability to really know the user as well as the lack of access to the setting for long term evaluation require the evaluator to use a series of tools and techniques. This paper discusses the results of using a keystroke log file to identify the use and visitor usage patterns of the sophisticated interactive multimedia system installed at the Wexner Learning Center of the United States Holocaust Memorial Museum. The findings of the evaluation include the identification of four typical sessions, a series of engagements with the technology and with the content and the need for other evaluation techniques to determine the cause of some of the exhibited behaviors.
Clinical Pharmacokinetics of the Prodrug Oseltamivir and its Active Metabolite Ro 64-0802

Oseltamivir is an ethyl ester prodrug of Ro 64-0802, a selective inhibitor of influenza virus neuraminidase. Oral administration of oseltamivir delivers the active antiviral Ro 64-0802 to the bloodstream, and thus all sites of influenza infection (lung, nasal mucosa, middle ear) are accessible. The pharmacokinetic profile of oseltamivir is simple and predictable, and twice daily treatment results in effective antiviral plasma concentrations over the entire administration interval. After oral administration, oseltamivir is readily absorbed from the gastrointestinal tract and extensively converted to the active metabolite. The absolute bioavailability of the active metabolite from orally administered oseltamivir is 80%. The active metabolite is detectable in plasma within 30 minutes and reaches maximal concentrations after 3 to 4 hours. After peak plasma concentrations are attained, the concentration of the active metabolite declines with an apparent half-life of 6 to 10 hours. Oseltamivir is eliminated primarily by conversion to and renal excretion of the active metabolite. Renal clearance of both compounds exceeds glomerular filtration rate, indicating that renal tubular secretion contributes to their elimination via the anionic pathway. Neither compound interacts with cytochrome P450 mixed-function oxidases or glucuronosyltransferases. The pharmacokinetic profile of the active metabolite is linear and dose-proportional, with less than 2-fold accumulation over a dosage range of oseltamivir 50 to 500mg twice daily. Steady-state plasma concentrations are achieved within 3 days of twice daily administration, and at a dosage of 75mg twice daily the steady-state plasma trough concentrations of active metabolite remain above the minimum inhibitory concentration for all influenza strains tested. Exposure to the active metabolite at steady state is approximately 25% higher in elderly compared with young individuals; however, no dosage adjustment is necessary. In patients with renal impairment, metabolite clearance decreases linearly with creatinine clearance. A dosage reduction to 75mg once daily is recommended for patients with creatinine clearance <30 ml/min (1.8 L/h). The pharmacokinetics in patients with influenza are qualitatively similar to those in healthy young adults. In vitro and in vivo studies indicate no clinically significant drug interactions. Neither paracetamol (acetaminophen) nor cimetidine altered the pharmacokinetics of Ro 64-0802. Coadministration of probenecid resulted in a 2.5-fold increase in exposure to Ro 64-0802; however, this competition is unlikely to result in clinically relevant effects. These properties make oseltamivir a suitable candidate for use in the prevention and treatment of influenza.
Effect of 7,12-dimethylbenz(a)anthracene on the integument of the hibernating and nonhibernating 13-lined ground squirrel

1. DMBA, a chemical carcinogen, was topically applied to skin patches of hibernating and nonhibernating ground squirrels (Spermophilus tridecemlineatus). 2. Macroscopically, hyperpigmentation, hair loss and excessive skin sloughing were evident in all treated nonhibernator skin patches. 3. Histological sections of skin revealed hyperkeratosis, epidermal vesicles, acanthosis, an indistinct basal layer and increased vascularization in nonhibernators. 4. Skin patches on hibernators were unaffected by treatment showing hibernation confers protection from the pathological effects of DMBA.
Neurogenesis in adolescent brain is potently inhibited by ethanol

Adolescence is a period of progressive changes in brain that likely contribute to the maturation of behavior. Human adolescents consume large amounts of ethanol. To investigate the effects of ethanol on adolescent neural progenitor cells, male rats (35-40 days old) were treated with an acute dose of ethanol (1.0, 2.5 or 5.0 g/kg, i.g.) or vehicle that resulted in peak blood levels of 33, 72, and 131 mg/dl, respectively. Bromodeoxyuridine (300 mg/kg i.p.) was administered to label dividing cells and rats were killed at 5 h to assess proliferation or at 28 days to assess cell survival and differentiation. After 5 h, bromodeoxyuridine-immunoreactivity was reduced by 63, 97 and 99% in the rostral migratory stream and 34, 71 and 99% in the subventricular zone by 1.0, 2.5 and 5.0 g/kg of ethanol respectively. In the dentate gyrus, ethanol reduced bromodeoxyuridine-immunoreactivity by 29, 40, and 78% at the three doses respectively. The density of doublecortin immunoreactivity was decreased after 3 days and the number of bromodeoxyuridine+ cells remained decreased at 28 days when most hippocampal bromodeoxyuridine+ cells coexpressed neuronal nuclei, a neuronal marker. These studies indicate that the adolescent brain is very sensitive to acute ethanol inhibition of neurogenesis.
A choice of approach: Second language learning

Abstract This article considers a number of approaches to second language learning and teaching. It discusses the different approaches within the context of the motivation students bring to second language learning. The author proposes a synthesis of different linguistic theories to be considered in designing second language teaching systems. The synthesis emanated from her personal experiences in teaching young Mexican American adolescents in the south-western United States.
Sky writer: sketch-based collaboration for UAV pilots and mission specialists

Sky Writer is a collaborative communication medium that augments the traditional display of a UAV pilot and allows other stakeholders to communicate their needs and intentions to the pilot. UAV pilots engaging in time-critical missions, such as urban disaster responses, often must allocate most of their cognitive capacity towards flight tasks, making communication and collaboration with other stakeholders difficult or dangerous. Sky Writer addresses the needs of stakeholders while requiring minimal cognitive effort from the UAV pilot. The application presents stakeholders with an interface that provides contextual flight information and a live video stream of the flight. Stakeholders are able to sketch directly on the video stream or use a spotlight indicator that is mirrored across all displays in the system, including the pilot's display. The application can be used in any modern web browser and works with traditional and touch devices. Concept experimentation performed at Disaster City with two pilots indicated that the spotlight feature was particularly useful while the UAV was in motion, and the sketching features were most useful while the UAV was stationary. The system will be tested with professional responders soon to determine its efficacy in a simulated response, and to inform the ongoing design process.