cssi/SciSciGPT-SciSciNet huggingface dataset:
Thiol−Allyl Ether−Methacrylate Ternary Systems. Polymerization Mechanism

The polymerization mechanism of the ternary thiol−allyl ether−methacrylate monomer system has been investigated. The effects of various factors including the thiol concentration, functionality, and structure on the polymerization mechanism, the polymer network structure, and mechanical properties were examined. The thiol−allyl ether−methacrylate ternary system uniquely exhibits two different polymerization regimes: a methacrylate homopolymerization dominated regime coupled with chain transfer to thiol followed by a second thiol−ene polymerization dominated regime. This polymerization mechanism is primarily due to the chemical nature of the methacrylate and allyl ether double bonds. Because methacrylate homopolymerization with chain transfer reactions to thiols dominates the initial stage of polymerization (up to 60% of the methacrylate conversion), the concentration and structure of the thiol significantly affect the polymerization processes and polymer network structure. The methacrylate chain length si...
Lewis acidity as an explanation for oxide promotion of metals : implications of its importance and limits for catalytic reactions

Sub-monolayer quantities of metal oxides are found to influence CO hydrogenation, CO2 hydrogenation, acetone hydrogenation, ethylene hydroformylation, ethylene hydrogenation, and ethane hydrogenolysis over Rh foils. The metal oxides investigated include AlOx, TiOx, VOx, FeOx, ZrOx, NbOx, TaOx, and WOx. Only those reactions involving the hydrogenation of C-O bonds are enhanced by the oxide overlayers. The coverage at which maximum rate enhancement occurs is approximately 0.5 ML for each oxide promoter. Titanium, niobium, and tantalum oxides are the most effective promoters. XPS measurements after reaction show that of the oxides studied titanium, niobium, and tantalum oxide overlayers are stable in the highest oxidation states. The trend in promotion effectiveness is attributed to the direct relationship between oxidation state and Lewis acidity. For the oxide promoters, bonding at the metal oxide/metal interface between the O-end of adsorbed CO and the Lewis acidic oxide is postulated to facilitate C-O bond dissociation and subsequent hydrogenation.
Localization of Vagal Afferents Involved in the Maintenance of Normal Avian Respiration

Abstract INTRODUCTION THE study of neural control of respiration has proved to be a particularly intractable subject. Lambertsen (1961) has emphasized that even today only hypotheses exist concerning the control of respiration in some states, such as exercise. The genesis of cyclic respiratory activity lies within the medulla oblongata, as measured in goldfish (Adrian and Buytendijk, 1931) or carp and catfish (Hukuhara and Okada, 1956). The influence of afferent impulses carried by the vagus on the medullary respiratory pool of neurons is the controversial subject of many published works, particularly in mammals (Sharpey-Schafer, 1919; Hammouda and Wilson, 1932; and Huber, 1957). Bilateral, cervical vagotomy affects respiration in all tetrapods studied (see Nikolaides, 1910 for amphibian work; see Siefert, 1896 for reptilian work; see Zander, 1879; Couvreur, 1891; Nikolaides, 1914; and Sinha, 1958 for avian work). Vagotomy was once considered to have no effect on the respiration of Anurans since alteration in…
Recurrent Conjugal Neuralgia Caused by Herpesvirus Hominis Type 2

Leg neuralgia is usually caused by nerve root irritation, and is seldom considered of viral origin. Two married couples had recurrent leg pain in a dermatome distribution. In each episode, after one to three days of neuralgia, herpetic vesicles appear on or near the genitalia. Herpesvirus hominis (HVH) was isolated from vesicles or cervix in three patients and was serologically identified as herpesvirus hominis type 2. Prolonged follow-up has not shown progression of the syndrome or any permanent neurologic damage. Treatment with topical neutral red and photoinactivation has not only reduced local lesion healing time and frequency of attacks, but it has also given prompt relief of neuralgia. ( JAMA 236:587-588, 1976)
Surface Reconstruction From Triple Dexel Model for Virtual Sculpting

This paper presents a novel method for surface reconstruction from triple dexel data for virtual sculpting. A triple dexel based virtual sculpting system is developed to provide the capability of interactive solid modeling with haptic interface. A solid model is converted to triple dexel data, which depicts the intersections of the solid with rays cast in three orthogonal directions, and modified during the virtual sculpting process. The boundary of the tool swept volume is computed based on the Sweep Differential Equation method. Contour generation and combination algorithms convert the triple dexel data to three sets of orthogonal slices of contours. A tiling algorithm then generates the solid’s boundary surface in triangular facets from these contours. Examples are given to demonstrate the ability of the developed method and software to realistically simulate the physical sculpting process and to allow viewing the sculpted models in any directions.Copyright © 2007 by ASME
Souvenirs of death

AbstractWar souvenirs collected from 1914 to 1918 by soldiers and civilians, men and women, offered a symbolic route of communication with the realm of death. Through the culture of war objects, collectors consciously staked claims about historical authenticity and about military power. For the soldier, a souvenir could serve as an aide-mmoire to actualize the past and to trigger narrative. For a grieving widow, a souvenir might memorialize the dead. Just as collections of objects build series, war narratives build on lists that collect objects, vignettes about individual soldiers, and a succession of losses. When narrative breaks down, such lists foreground the problem of connection and the difficulty of constructing meaning out of calamity. The importance of these uncanny objects springs from the collective experience of trauma.
SURVIVORSHIP AND FECUNDITY OF THE POLYCARPIC PERENNIAL MENTZELIA NUDA (LOASACEAE) IN NEBRASKA SANDHILLS PRAIRIE

Survivorship and fecundity of the polycarpic perennial Mentzelia nuda were investigated to help understand its population dynamics. Between 1978 and 1984, all 685 individuals found in a Nebraska sandhills prairie plot were marked and their fate followed. Three plants lived seven years, but the average lifespan was less than two years. Most plants spent their first year as nonflowering rosettes: only 9% flowered the first summer after germination. Overall, firstyear survivorship ranged from 0.20 to 0.50 between 1978 and 1984. Fifty-two percent of rosettes survived to flower. Survivorship of flowering individuals was about the same as the survivorship of rosettes, although actual survivorships varied significantly between years. Both rainfall and age affected survivorship and fecundity.
Analysis of gamete and zygote motility in Allomyces.

Abstract To study the mechanisms of chemotaxis in eukaryotes, the motility patterns of the gametes and zygotes and the chemotactic responses of the male gametes of the lower eukaryote Allomyces macrogynus were examined. Dark-field microscopy of the male gametes showed a smooth swimming pattern interrupted by very brief ‘jerks’ of the cell body that caused a change in swimming direction. Female gametes had a slower swimming velocity than the males and underwent more jerks or turns which accounted for their sluggish motility. The zygotes swam with the fastest velocity and were observed to have a helical swimming pattern involving a continuous turning of the cell body, a behavior absent from the gametes. Introduction of female gametes that produce the chemoattractant sirenin brought about an immediate change in the behavior of the male gametes. They moved in spirals (or helices) towards the source of the chemoattractant (the female gametes), undergoing only a few jerks to reorient the male cells. When very near the female cells, or in high concentrations of added sirenin, many very short motility tracks were observed that finally resulted in contact between the two gamete types. The results indicate that the poor swimming ability of the female gametes facilitates gamete contact, resulting in as many as 30–40 male gametes clustered on a single female cell. Further, male gamete orientation to the sirenin gradient is caused by the chemoattractant suppressing the jerk motion.
Preliminary design calculations for an ionization spectrometer for use in colliding beam experiments

Abstract The calculated response of an ionization spectrometer containing NaI, Fe, and Ar to charged pions and kaons in the 0.1–1.0 GeV / c momentum range is presented.
Poor Families in America's Health Care Crisis

1. The unrealized hope of welfare reform: implications for health care 2. The health care welfare state in America 3. The tattered health care safety net for poor Americans 4. State differences in health care policies and coverage 5. Work and health insurance: a tenuous tie for the working poor 6. Confronting the system: minority group identity and powerlessness 7. The nonexistent safety net for parents 8. Health care for all Americans.
Electroless deposition of Au around electrochemically evolved hydrogen bubbles

Abstract In this report, we use stripe-patterned substrates and TEM grids as working electrodes to demonstrate that electrochemically evolved hydrogen bubbles can serve as templates and reducing agents for electroless deposition of Au from a Na 3 Au(SO 3 ) 2 electrolyte to form hollow particles. This new hollow nanoparticle formation mechanism, which is termed as bubble template synthesis, has the potential to become a general route to the fabrication of various metallic hollow nanoparticles. We have also found that the addition of Ni 2+ ions in the electrolyte has an effect on the particle formation process. Electrodeposited metallic Ni enhances the hydrogen evolution and therefore the hollow particle formation. It also leads to an improved size distribution of the hollow particles.
Dependence flow graphs: an algebraic approach to program dependencies

The topic of intermediate languages for optimizing and parallelizing compilers has received much attention lately. In this paper, we argue that any good representation must have two crucial properties: first, the representation of a program must be a data structure that can be rapidly traversed to determine dependence information; second, the representation must be a program in its own right, with a parallel, local, model of execution. In this paper, we illustrate the importance of these points by examining algorithms for standard optimization-global constant propagation. We discuss the problems in working with current representations. Then, we propose a novel representation called the dependence flow graph which has each of the properties mentioned above. In this representation, dependencies are part of the computational mode, in that there is an algebra of operators over dependencies. We show that this representation leads to a simple algorithm, based on abstract interpretation, for solving the constant propagation problem. Our algorithm is simpler than, and as fast as, the best known algorithms for the problem. An interesting feature of our representation is that it naturally incorporates the best aspects of many other representations, including continuation-passing style, data and program dependence graphs, static single assignment form and dataflow program graphs.
Experimental characterization of the tensile behaviour of Nicalon fibre-reinforced calcium aluminosilicate composites

Mechanical behaviour studies were conducted on Nicalon SiC/calcium aluminosilicate (CAS) composites. Tensile tests were carried out to study the stress-strain behaviour, as well as to identify the failure mechanisms, of unidirectional and cross-ply SiC/CAS composites. The evolution of the various damage modes and the synergistic effects among them were investigated. The effect of the 90° ply thickness on the damage modes was also determined. The composite stiffness reduction during damage evolution was evaluated. A tensile test specimen was designed for glass and glass-ceramic composites to avoid end-tab shear failure and expensive machining as well as to reduce the effect of bending due to misalignment. The results of this work provide insight into the stress-strain behaviour and damage mechanisms of continuous fibre-reinforced ceramic composites which can be very valuable in design with these materials.
Electrothermal modeling of a microbridge gas sensor

Fully CMOS-compatible, surface-micromachined polysilicon microbridges have been designed, fabricated, and tested for use in catalytic, calorimetric gas sensing. To improve sensor behavior, extensive electro-thermal modeling efforts were undertaken using SPICE. The validity of the SPICE model was verified comparing its simulated behavior with experiment. Temperature distribution of an electrically heated microbridges was measured using an infrared microscope. Comparisons among the measured distribution, the SPICE simulation, and distributions obtained by analytical methods show that heating at the ends of a microbridges has important implications for device response. Additional comparisons between measured and simulated current-voltage characteristics, as well as transient response, further support the accuracy of the model. A major benefit of electro- thermal modeling with SPICE is the ability to simultaneously simulate the behavior of a device and its control/sensing electronics. Results for the combination of a unique constant-resistance control circuit and microbridges gas sensor are given. Models of in situ techniques for monitoring catalyst deposition are shown to be in agreement with experiment. Finally, simulated chemical response of the detector is compared with the data, and methods of improving response through modifications in bridge geometry are predicted.
PRACTICAL PROBLEMS WITH VETERINARY ANAESTHESIA MACHINES

SUMMARY Many types of anaesthetic machines are available to practicing veterinary surgeons, ranging from the obsolescent to the most modern. To practice anaesthesia safely, veterinary surgeons should understand the functions of the machines, vaporizers, and breathing systems with which they work. In addition, veterinary surgeons should employ procedures for evaluation of their anaesthetic equipment to assure, as much as possible, safety for their patients and the personnel who use the apparatus.
Linkage isomerization of [Co(NH3)5ONO]2+ in poly(vinyl alcohol)

Abstract The rate of linkage isomerization of nitritopentaamminecobalt (III) to the nitro form was measured spectrophotometrically in poly(vinyl alcohol) sheets at three temperatures. The nitrito complex was generated photochemically.
A Deep Infrared Photometric Survey for Very Low Mass Brown Dwarfs in the Pleiades

This paper presents the results of a deep infrared survey for low-mass brown dwarfs in the Pleiades cluster. By comparing J-band (1.25 μm) and I-band (0.83 μm) photometry of an ~450 arcmin2 area with the latest theoretical models of pre-main-sequence substellar evolution, a number of candidates were identified with J-band magnitudes and I - J color limits consistent with Pleiades membership. The mean 10 σ completeness limits of J = 19.25 and I = 23.25 mag correspond to an age-dependent (80–125 Myr) effective depth of (23–28)MJ at which Pleiades members of late L spectral types and temperatures near ~1650 K (I - J color ~4 mag) are predicted to begin making a transition to methane-dominated spectra. Of the preliminary candidates, three are more likely field stars, one is a previously known Pleiades brown dwarf (BPL 81), and the remaining are new substellar candidates, all ranging in membership-dependent mass (again for 80–125 Myr ages) from (22–26)MJ to (46–57)MJ. Follow-up infrared photometry and higher resolution image profile analysis with the Keck telescopes have eliminated all except about five new substellar Pleiades candidates as likely cluster members. Additional follow-up observations including proper-motion and spectral analysis, as well as more comprehensive multiband imaging, will be required to clarify membership likelihood for these Pleiades candidates. Any of the remaining new substellar candidates presented herein, if confirmed as cluster members, would be the lowest mass brown dwarfs discovered in the Pleiades by any survey to date.
Reactivity of CFn (n=1–3) species with a silica surface

Abstract The trends in reactivity of CF n neutrals with a silica surface are studied using two different cluster models. CF appears to be the most reactive species. The energetics, the activation energies, and the forward reaction rates are computed for two reactions involving the SiO bond breaking.
Differential Geometries of Function Space.

In a previous paper (1) the author initiated the study of a species of functional differential geometries. These geometries are the function space analogues of the n-dimensional theories of affinely connected manifolds. An attempt to develop a projective theory in function space was instrumental in showing that the functional geometries which were developed in the cited paper (1) were a truncated form of a much more general situation.
The transformation of southern California's residential photovoltaics market through third-party ownership

Third-party photovoltaics (PV) ownership is a rapidly growing market trend, where commercial companies own and operate customer-sited PV systems and lease PV equipment or sell PV electricity to the building occupant. Third-party PV companies can reduce or eliminate up-front adoption costs, reduce technology risk and complexity by monitoring system performance, and can repackage the PV value proposition by showing cost savings in the first month of ownership rather than payback times on the order of a decade. We find that the entrance of third-party business models in southern California residential PV markets has enticed a new demographic to adopt PV systems that is more highly correlated to younger, less affluent, and less educated populations than the demographics correlated to purchasing PV systems. By enticing new demographics to adopt PV, we find that third-party PV products are likely increasing total PV demand rather than gaining market share entirely at the expense of existing customer owned PV demand. We also find that mean population demographics are good predictors of third-party and customer owned PV adoption, and mean voting trends on California carbon policy (Proposition 23) are poor predictors of PV adoption.
Storage stability of poultry fat and diesel fuel mixtures: Part II – Chemical properties

This publication continues previously published work from the authors which evaluates the storage potential of poultry fat for its use as an unmodified biofuel in heat and steam generating systems [1]. The previous work examined the physical properties of these fats while this study is concerned with chemical properties. In this study poultry fat (biofuel) and its 20%, 40%, 60% and 80% mixtures with #2 pump diesel fuel were stored for 1 year at bench scale (1L) under controlled laboratory conditions at 4, 38, 54.4 °C and at 22 °C. One hundred percent of poultry fat was studied under these same conditions with and without an antioxidant additive. Twenty and eighty percent of poultry fat mixtures were also stored at pilot scale (250 gallons) under outdoor, ambient conditions. Chemical properties relevant to the use of these mixtures as a biofuel for industrial boilers were studied and tracked. These properties include Energy Values (BTU), Ultimate Analysis (carbon, hydrogen, oxygen, ash, nitrogen, and sulfur), moisture, impurities, unsaponafiables (MIU), and Free Fatty Acid Content. Energy content of the biofuel samples dropped over the course of the study with untreated biofuel losing 18.9% of its BTU value over the course of a year. Ultimate analyses showed an overall increase in carbon composition and a decrease in oxygen content. Hydrogen levels increased in most treatments as did overall ash and sulfur percent composition. MIU values increased, this overall increase was attributable to variable increases in insolubles and unsaponifiables. Free fatty acid levels increased in all treatments. Most of the chemical changes observed in this study were reduced by the addition of antioxidant to 100% biofuel.
High-frequency fiber-optic phase modulator

Extensive research has been directed toward development of fiber-optic sensors mainly based on phase modulation. For applications such as phase sensors, phase modulators are useful for optimizing sensor performance. We have made an integrated phase modulator by coating single-mode fibers with a vinylidene fluoride-tetrafluoroethylene (PVF2-TFE) copolymer radially poled. The phase sensitivity of the fiber has been studied both analytically and experimentally in the wide range from 1 kHz to 350 MHz.
Active Na+ uptake in the isolated midgut of larval Sarcophaga bullata

Abstract The isolated midgut of larval Sarcophaga bullata actively accumulates Na+ from the gut lumen into the haemolymph. The active transport of Na+ out of the gut lumen is responsible for the transepithelial potential difference measured across the midgut epithelium, such that the midgut lumen is negative in respect to the haemolymph side. Both the net movement of Na+ out of the midgut lumen and the transepithelial potential are inhibited by CN− and, in addition, the potential in blocked by ouabain.
Conformational Gating of Long Distance Electron Transfer through Wire-like Bridges in Donor−Bridge−Acceptor Molecules

A series of five donor−bridge−acceptor (DBA) molecules in which the donor is tetracene, the acceptor is pyromellitimide, and the bridge molecules are oligo-p-phenylenevinylenes (OPV) of increasing length has been shown to undergo electron transfer (ET) by means of two mechanisms. When the bridge is short, strongly distance dependent superexchange dynamics dominates, whereas when the bridge is longer, bridge-assisted hopping dynamics prevails. The latter mechanism results in relatively soft distance dependence for ET in which the OPV oligomers act effectively as molecular wires. We now report studies on the critical influence that bridge dynamics have on electron transfer through these oligomers. The temperature dependence of the charge separation (CS) rates in all five molecules does not appear to obey the predictions of standard ET theories based upon the Condon approximation. All five molecules show behavior consistent with CS being “gated” by torsional motion between the tetracene donor and the first b...
Epidemic Tuberculosis in a Nursing Home: A Retrospective Cohort Study

In a retrospective study, the results of tuberculin skin tests done in a nursing home were examined, where most residents admitted during 1972-1981 were tested using purified protein derivative of tuberculin administered intradermally. Of 514 residents who were tested at least once during the study period, results of the admission skin test were available for 254 and follow-up skin test results were available for 226. On admission, 13 per cent (35/254) were skin-test positive (greater than or equal to 10 mm induration at 48 hours). Skin test positivity for males was 16 per cent, females, 11 per cent, nonwhites, 19 per cent, and whites, 12 per cent. Highest skin test positivity was for persons received as transfers from other nursing homes (24 per cent) and lowest was for those entering from individual homes (8 per cent, P = 0.016, Fisher's Exact Test). On follow-up, 38/226 (17 per cent) residents who had been tuberculin-negative on at least two previous occasions were found to be positive; 24 (63 per cent) of these conversions occurred in a single year (1975) following detection of an infectious patient. The infection rate for persons residing in the nursing home during that year was 28 per cent (28/99) compared with 7.9 per cent (10/127) for persons either discharged before or admitted after 1975 (relative risk = 3.6, P less than 0.001). Ten to 15 per cent of new residents are tuberculin-positive (harbour a dormant tuberculous infection), leaving 85-90 per cent of newly admitted persons who are tuberculin-negative and thus susceptible to infection if exposed. The study shows that tuberculosis must be considered as a potential nosocomial infection in nursing homes.(ABSTRACT TRUNCATED AT 250 WORDS)
Availability of cigarettes to underage youth in three communities.

Abstract Background . Underage youth report that they primarily obtain cigarettes from commercial sources. Thus policies that effectively prevent purchase by minors could have an effect on the prevalence of young people's cigarette use. Methods . In this study, 12- to 15-year-old male and female confederates attempted to purchase cigarettes from all cigarette outlets in three communities. Results . A success rate of 53% over the counter and 79% from vending machines was achieved. These results show that minors can purchase cigarettes in all types of businesses, even those characterized as “adult” locations. Boys in this study had more difficulty than girls in purchasing cigarettes over the counter, and younger individuals had more difficulty than 15-year-olds. However, these differences were not found in vending machine sales. Similarly, over-the-counter sales of cigarettes were significantly reduced following a statewide increase in the penalty for tobacco sales to minors, but vending machine sales were not affected. Conclusions . These results support stringent and universal controls over the sale of cigarettes as an essential part of any tobacco use prevention strategy.
Alternative theories of concept identification among older adults.

Summary.-The purpose of the present experiment was to investigate some predictions of hypothesis testing and S-R association (frequency) theories regarding memory for intratrial events on a conjunctive concept-identification task. They have received extensive study with young adults but not with older subjects. The individual, events under investigation were feedback, responses, hypotheses, and stimuli. Hypothesis-testing theory requires subjects to retain information concerning the correct hypothesis from one trial to the next whereas frequency does not. 75 subjects (60-70 yr. old) participated in the study. Subjects had difficulty in recalling the correct hypothesis stated on previous trials. These errors occurred on problems with negative response trials, not with incorrect feedback. The results contradict predictions based on hypothesis-testing models but are consistent with frequency theory. Unlike in the studies based on younger adults, present subjects did not recall the hypothesis very well under the conditions in which hypothesis testing was made part of the primary task. The major purpose of this experiment was to test some predictions of hypothesis and S-R association (frequency) theories of concept formation. Unlike most other studles of this nature, older adults served as subjects rather than young adults. Over the past two decades various hypothesistesting models have emerged as a dominant class of theories to explain how concepts are acquired. Based on findings of the 1960s and early 70s, they appeared to provide the best explanation of how subjects identify relevant features from various stimuli which constitute a concept (Kellogg, Robbins, & Bourne, 1778) as opposed to alternative associative theories. However, recent studies discussed below yield data which demonstrate the inability of hypothesis theory to explain all of the relevant aspects of concept learning. Troublesome for hypothesis theory are the recent findings about the selectivity of memory for intratrial events in concept formation such as feedback, responses, stimuli, and hypothesis. Although differences exist between the various models of hypothesis-testing, concerning how we1 subjects should remember the various intratrial events, they all require that subjects must maintain information about the current hypothesis or concept from one trial to the next, whereas S-R theory does not. As a consequence, all of the hypothesis-testing models predict that subjects wlll recall the hypothesis tested on that immediately preceding trial which leads to a correct response. For example, Restle's (1762) version of hypothesis-testing theory, Levine's (1969) "focusing" theory, Trabasso and Bower's (1966) "consistency
Fast aggregation of colloidal silica

The aggregation kinetics of colloidal silica is highly dependent on conditions such as the {ital p}H and salt concentration. In this paper we investigate the aggregation of colloidal silica under conditions that promote rapid growth, contrasting our findings with earlier investigations of the slow growth of silica. A number of interesting effects are observed, including power-law growth of the mean aggregate radius, dependence of the aggregation rate on concentration and the chemical nature of the salt used, a reduced aggregate fractal dimension, fragmentation of the fast aggregates under changing solution conditions, and shear-induced restructuring of aggregates. Finally, we present evidence that the fractal dimension of aggregates is not strongly universal, but depends weakly on such factors as the solution concentration. We conclude that although the diffusion-limited cluster-cluster aggregation model gives a good first-order description of rapid aggregation, real systems exhibit richer behavior that is not given to such a facile interpretation.
On the interactions between atmospheric radicals and cloud droplets: A molecular picture of the interface

How gas-phase materials become incorporated with cloud droplets has been an intriguing subject for decades, and considerable work has been done to understand the interactions between closed-shell molecules and liquid water. The interactions between open-shell radical species and liquid-phase cloud droplets, however, are not well understood. To probe these interactions we used quantum chemistry calculations to predict the energetics of the hydroperoxy radical (HO2) in the presence of an (H2O)20 spherical water cage. Our calculations show that it is energetically favorable for the radical to bind to the outside of the cage. This configuration has the hydrogen and the terminal oxygen of the radical as its primary bonding sites. Free-energy calculations suggest that, at atmospheric conditions, there will be a partitioning between HO2 radicals that are surface-bound and HO2 radicals that dissolve into the bulk. This may have important ramifications for our understanding of radical chemistry and may lend insight into the role that clouds and aerosols play in atmospheric chemical processes.
Presence of Intact vpu and nef Genes in Nonpathogenic SHIV Is Essential for Acquisition of Pathogenicity of This Virus by Serial Passage in Macaques

Abstract Use of the macaque model of human immunodeficiency virus (HIV) pathogenesis has shown that the accessory genes nef and vpu are important in the pathogenicity of simian immunodeficiency virus (SIV) and simian–human immunodeficiency virus (SHIV). We examined the ability of two nonpathogenic SHIVs, SHIV PPC and Δ vpuΔnef SHIV PPC , to gain pathogenicity by rapid serial passage in macaques. In this study, each virus was passaged by blood intravenously four times at 4-week intervals in macaques. Animals were monitored for 40 weeks for levels of CD4 T cells and quantitative measures of virus infection. Δ vpuΔnef SHIV PPC maintained a limited phase of productive replication in the four animals, with no loss of CD4 + T cells, whereas SHIV PPC became more pathogenic in later passages, judging by plasma viral load and viral mRNA in lymph nodes, infectious peripheral blood mononuclear cells and CD4 + T cell loss. The nef, LTR, and env of the SHIV PPC viruses underwent numerous mutations, compared to Δ vpuΔnef SHIV PPC . This study confirms the seminal role that nef, LTR, and vpu could play in regulation of pathogenesis of HIV infection.
Electronic structure and ground states of transition metals encapsulated in a Si 12 hexagonal prism cage

We report on a computational study of the electronic structure of recently discovered clusters with an encapsulated transition metal (TM) atom in a ${\mathrm{Si}}_{12}$ hexagonal prism cage. The cage geometry is remarkably stable regardless of the type of doping TM atom from $3d,4d,$ and $5d$ series. We predict and quantify the stability for several other TM dopings besides the experimentally observed ones. The multiplicity of the ground states can be ``tuned'' between singlets and triplets by varying the type of TM atom (even number of electrons), while they are doublets for odd number of electrons. We also explore the possibility of forming solids with hexagonal structure from selected clusters.
Synthesis of α-Gal epitope derivatives with a galactosyltransferase–epimerase fusion enzyme

Alpha-Gal epitopes are carbohydrate structures bearing an alpha-D-Galp-(1-->3)-beta-D-Galp terminus and are the main cause of antibody-mediated hyperacute rejection in xenotransplantation. Nine monosaccharides and ten disaccharides were evaluated as substrates for a fusion protein, which contains both alpha-(1-->3)-galactosyltransferase and uridine-5'-diphosphogalactose 4-epimerase. Four disaccharide and six trisaccharide alpha-Gal epitope derivatives were synthesized utilizing this novel fusion enzyme.
Generalized running discrete transforms

This paper introduces a generalized running discrete transform with respect to arbitrary transform bases, and relates the generalized transform to the running discrete Fourier z and short-time discrete Fourier transforms. Concepts associated with the running and short-time discrete Fourier transforms such as 1) filter bank implementation, 2) synthesis of the original sequence by summation of the filter bank outputs, 3) frequency sampling, and 4) recursive implementations are all extended to the generalized transform case. A formula is obtained for computing the transform coefficients of a segment of data at time n recursively from the transform coefficients of the segment of data at time n - 1. The computational efficiency of this formula is studied, and the class of transforms requiring the minimum possible number of arithmetic operations per coefficient is described.
Phase I study of liposomal annamycin

Annamycin is a highly lipophilic anthracycline with the ability to bypass the MDR-1 mechanism of cellular drug resistance. In this phase I study, annamycin entrapped in liposomes was administered by a 1- to 2-h intravenous infusion at 3-week intervals. Thirty-six patients with relapsed solid tumors were treated and 109 courses were administered at doses ranging from 3 to 240 mg/m2. The dose-limiting toxicity was thrombocytopenia. Five patients had a probable allergic reaction, requiring discontinuation of treatment in one. Treatment was well tolerated otherwise. No cardiac toxicity was seen on endomyocardial biopsy of four patients studied. There was limited gastrointestinal toxicity and no alopecia. No objective tumor responses were observed. Pharmacokinetic studies at 24, 120 and 240 mg/m2 showed a biexponential plasma concentration-versus-time profile. There was a linear relationship between the dose and the maximal plasma concentration with relatively constant plasma clearance values. The maximum tolerated dose (MTD) for liposomal annamycin defined in this study is 210 mg/m2. Because of a subsequent change in the formulation of the drug, future studies will use 190 mg/m2 as the MTD.
Variations of the Flexor Digitorum Superficialis Tendon of the Little Finger

Seventy cadaveric hands were dissected to study variations of the flexor digitorum superficialis tendon (FDS) to the little finger. Anatomical variations were present in 13% of hands and 10% of the hands showed an anatomical variation that would preclude independent FDS function in the little finger. The distance of the decussation from the metacarpophalangeal joint was measured. A ratio of this distance to proximal phalangeal length was calculated. The ratio indicated that decussation position was independent of phalangeal size.
Field desorption mass spectrometry of complex anions containing rhenium and technetium

Abstract Field desorption mass spectra of Technetium and Rhenium anionic coordinate complexes have been obtained. lonization was principally by electron extraction from the anion, cation or neutral anion-cation pair, or by cation attachment to the intact molecule. The spectra were generally simple and allowed confirmation of known of proposed coordinate complex structures.
The immunocompromised adult patient and surgery

The perioperative management of immunosuppressed patients remains relatively unsophisticated. Rational management involves understanding the normal immune response to injury as modified by the preexisting or imposed abnormalities that immunosuppressed patients manifest on the basis of their disease and/or treatment. Patients with cancer, infected with human immunodeficiency virus, and having had an organ transplant are extreme examples of disordered immunity and it is important to understand the effects of their diseases and treatments. In the future, however, more appropriate management will require anticipation and appreciation of frequent preoperative immunotherapy, a more complete understanding of the immunological response to anesthesia and surgery, the ability to assess immune reserve and stratify risk within the context of that profile, and a better knowledge of the immunological effect of anesthetic agents.
Ascending caudal medullary catecholamine pathways drive sickness-induced deficits in exploratory behavior: Brain substrates for fatigue?

Immune challenges can lead to marked behavioral changes, including fatigue, reduced social interest, anorexia, and somnolence, but the precise neuronal mechanisms that underlie sickness behavior remain elusive. Part of the neurocircuitry influencing behavior associated with illness likely includes viscerosensory nuclei located in the caudal brainstem, based on findings that inactivation of the dorsal vagal complex (DVC) can prevent social withdrawal. These brainstem nuclei contribute multiple neuronal projections that target different components of autonomic and stress-related neurocircuitry. In particular, catecholaminergic neurons in the ventrolateral medulla (VLM) and DVC target the hypothalamus and drive neuroendocrine responses to immune challenge, but their particular role in sickness behavior is not known. To test whether this catecholamine pathway also mediates sickness behavior, we compared effects of DVC inactivation with targeted lesion of the catecholamine pathway on exploratory behavior, which provides an index of motivation and fatigue, and associated patterns of brain activation assessed by immunohistochemical detection of c-Fos protein. LPS treatment dramatically reduced exploratory behavior, and produced a pattern of increased c-Fos expression in brain regions associated with stress and autonomic adjustments paraventricular hypothalamus (PVN), bed nucleus of the stria terminalis (BST), central amygdala (CEA), whereas activation was reduced in regions involved in exploratory behavior (hippocampus, dorsal striatum, ventral tuberomammillary nucleus, and ventral tegmental area). Both DVC inactivation and catecholamine lesion prevented reductions in exploratory behavior and completely blocked the inhibitory LPS effects on c-Fos expression in the behavior-associated regions. In contrast, LPS-induced activation in the CEA and BST was inhibited by DVC inactivation but not by catecholamine lesion. The findings support the idea that parallel pathways from immune-sensory caudal brainstem sources target distinct populations of forebrain neurons that likely mediate different aspects of sickness. The caudal medullary catecholaminergic projections to the hypothalamus may significantly contribute to brain mechanisms that induce behavioral "fatigue" in the context of physiological stressors.
Repetitive thought and emotional distress: Rumination and worry as prospective predictors of depressive and anxious symptomatology.

Repetitive thought processes have been implicated in vulnerability to both anxiety and depression. The present study used a prospective design to examine the ability of worry and rumination to predict these two forms of emotional distress over time. Participants were 451 college students (273 females) who completed self-report measures of rumination, worry, depression, and anxiety at two time points separated by 6–8 weeks. Results indicated that both worry and rumination prospectively predicted anxiety, whereas neither thought process prospectively predicted depressive symptomatology. Although females reported elevated levels of worry and rumination compared to males, gender did not moderate any of these effects. Based on these findings, it appears that repetitive thought in the form of both worry and rumination contributes to anxiety, whereas neither thought process contributed to the development of depressive symptomatology in the present sample. Post-hoc analyses raise the possibility that previously documented associations between rumination and depression may have been partially driven by criterion contamination between measures of these constructs (see J. E. Roberts, E. Gilboa, & I. H. Gotlib, 1998).
Polycrystalline thin-film transistors on plastic substrates

Flat panel displays made on plastic substrates are envisioned for use in certain commercial and military systems because they are more rugged and lightweight than displays made on glass substrates. High information content can be attained for such displays using an active matrix array of thin film transistors (TFTs) for the pixels and high current TFTs for the drivers. In this work the fabrication of high performance polysilicon TFTs on flexible plastic substrates is presented along with corresponding electrical characteristics. Plastic substrates pose severe temperature constraints on the fabrication process. To overcome electrical characteristics. Plastic substrates pose sever temperature constraints on the fabrication process. To overcome these constraints, our group at LLNL has used low temperature silicon, oxide, and aluminum thin film deposition steps and pulsed excimer laser processing to perform the TFT channel crystallization and the source/drain doping. Sheet resistance values below 1k(Omega) /$DAL are obtained using our laser doping technique for 900 angstrom thick polysilicon films. Our n-channel polysilicon TFT electrical performance on plastic shows mobilities up to 50 cm2/V-sec and ON current to OFF current ratios of up to 1 X 106 for gate voltages from -1 to +35 V.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Land-cover classification in a moist tropical region of Brazil with Landsat Thematic Mapper imagery

This research aims to improve land-cover classification accuracy in a moist tropical region in Brazil by examining the use of different remote-sensing-derived variables and classification algorithms. Different scenarios based on Landsat Thematic Mapper TM spectral data and derived vegetation indices and textural images and different classification algorithms, maximum likelihood classification MLC, artificial neural network ANN, classification tree analysis CTA and object-based classification OBC, were explored. The results indicate that a combination of vegetation indices as extra bands into Landsat TM multi-spectral bands did not improve the overall classification performance, but the combination of textural images was valuable for improving vegetation classification accuracy. In particular, the combination of both vegetation indices and textural images into TM multi-spectral bands improved the overall classification accuracy OCA by 5.6% and the overall kappa coefficient OKC by 6.25%. Comparison of the different classification algorithms indicated that CTA and ANN have poor classification performance in this research, but OBC improved primary forest and pasture classification accuracies. This research indicates that use of textural images or use of OBC are especially valuable for improving the vegetation classes such as upland and liana forest classes that have complex stand structures and large patch sizes.
Lagrangian subvarieties of the moduli space of stable vector bundles on a regular algebraic surface with pg > 0.

Mukai [M1] showed that there is a nondegenerate symplectic structures on the moduli space of stable vector bundles on a K3 surface. Later Tyurin [T2] studied (generalized) symplectic structures on the moduli space of stable vector bundles on any smooth regular surface X with P9 > 0. In the work of Tyurin, a symplectic structure means a nonzero regular two form on the moduli spaces, in particular it may degenerate. In this paper, we define a Lagrangian subvariety of the moduli space to be a subvariety on the Zariski tangent space (at any point) of which the given symplectic two form is identically zero. Note that we do not impose any restriction on the dimension of a Lagrangian subvariety. This is because symplectic structures considered here may degenerate. The purpose of this paper is to use Bril l-Noether theory for curves to construct explicit ly a family of Lagrangian subvarieties of the moduli space of stable vector bundles on a regular surface with pg > 0 . Le t . P/~ be a generically smooth and irreducible component of the moduli space of Gieseker-stable bundles of rank r + 1 with respect to a fixed polarization D on a regular algebraic surface X with p~ > 0. By the boundedness of ..Jf/~ (see [Ma]), after possibly twisted by the same negative line bundle . ~ on X, we can assume that for any point [E] C ,//J~, (i) E * is generated by global sections. (ii) hl(E *) = hZ(E *) : hi(E) : O. (iii) h l (de t E *) = hZ(det E *) = 0. For any point [E] c .//Z. Choose a (r + 1) dimensional subspace V C H~ and consider an evaluation map e v : V | P x --~ E* . For a general V, we can make e v degenerate exactly along a smooth curve C C X and coker e v is a line bundle
Intrinsic bending in GGCC tracts as probed by fluorescence resonance energy transfer.

Abstract Double-stranded oligonucleotides containing the sequence 5′-GGCC-3′ can be intrinsically bent, according to X-ray crystallography and gel electrophoresis mobility studies. We have performed fluorescence resonance energy transfer (FRET) experiments with dye-labeled oligonucleotides to further investigate the solution structure of this sequence. We find that 5′-GGCC-3′-containing oligonucleotides bring 5′-attached donor and acceptor dyes much closer together than a comparable “straight” sequence that contains 5′-GCGC-3′. The bend angle for the 5′-GGCC-3′ sequence is estimated to be ∼70°, much larger than the crystallographically observed 23° kink but in agreement with other FRET work. In contrast to gel electrophoresis studies, divalent metal ions do not promote increased kinking in 5′-GGCC-3′ above background as judged by FRET. Thus, sequence-dependent structural effects in DNA may be a complicating feature of FRET experiments.
Avoidance of Multiple Obstacles for a Mobile Robot With Nonholonomic Constraints

In this study, a decoupled controller, consisting of a force controller and a torque controller, is designed to achieve a smooth translational and rotational motion control of a group of nonholonomic mobile robots. The proposed controller also solves the problem of obstacle avoidance, where obstacles with arbitrary boundary shapes are taken into account. Since the tangential direction of obstacle boundary is adopted as the guiding direction of a robot, the proposed controller allows a mobile robot to escape from a concave obstacle, while the robot could be trapped with most of the conventional obstacle avoidance algorithms.Copyright © 2005 by ASME
Recent progress towards understanding the synaptic ribbon

Neurons of the visual, auditory and vestibular systems that signal through graded changes in membrane potential rely upon synaptic ribbons for the exquisite control of neurotransmitter release. Although clearly important for tonic neurotransmission, the precise role of synaptic ribbons remains elusive. In recent years, several genetic, biochemical, electrophysiological and optical approaches have begun to shed light on the functions of these enigmatic organelles.