cssi/SciSciGPT-SciSciNet huggingface dataset:
Growth, morphology, and optical and electrical properties of semicontinuous metallic films

The growth and optical properties of semicontinuous silver films on insulator substrates were studied experimentally and theoretically. In the experimental studies, films were synthesized by the pulsed-laser deposition technique, characterized by electron microscopy and in situ optical and dc electrical resistance measurements and studied using near-field optical microscopy. The percolation threshold of the films was found to be at \ensuremath{\sim}65% metal filling fraction, higher than the 50%--60% range of values predicted for two-dimensional (2D) bond or site percolation films and suggesting the importance of grain coalescence and 3D growth in our system. Local optical properties measured by near-field optical microscopy were compared with theoretical results obtained using the block-elimination method, with good agreement. Local-field distributions were found to depend strongly on the metal concentration and wavelength of illumination. The degree of localization was found to increase at metal concentrations both above and below the percolation threshold. At a very high metal coverage, very strong local fields were observed in submicron voids of a metal dielectric film. These fields are likely due to localized surface plasmon polaritons.
Inorganic particle toughening I: micro-mechanical deformations in the fracture of glass bead filled epoxies

General characteristics of micro-mechanical deformations found in the fracture of various glass bead filled epoxies are investigated. Among the various types of step features on fracture surfaces, the basic longitudinal texture is not influenced by the existence of glass beads, but most other steps formed are significantly affected. Various microscopic investigations show that microcracking does not extensively occur in the fracture of glass bead filled epoxies. Microcracking other than debonding of glass beads is seldom observed, and furthermore, debonding is found to occur only on and near the fracture surface. Micro-shear bands are clearly identified and distinguished from microcracks found in unnotched tensile specimens. Based on examination of micro-mechanical deformations, three types of fracture processes are proposed for glass bead filled epoxies having different glass bead contents and interfacial strengths.
Implications of Glucose Transporter Protein Type 1 (GLUT1)-Haplodeficiency in Embryonic Stem Cells for Their Survival in Response to Hypoxic Stress

Glucose transporter protein type 1 (GLUT1) is a major glucose transporter of the fertilized egg and preimplantation embryo. Haploinsufficiency for GLUT1 causes the GLUT1 deficiency syndrome in humans, however the embryo appears unaffected. Therefore, here we produced heterozygous GLUT1 knockout murine embryonic stem cells (GT1+/−) to study the role of GLUT1 deficiency in their growth, glucose metabolism, and survival in response to hypoxic stress. GT1(−/−) cells were determined to be nonviable. Both the GLUT1 and GLUT3 high-affinity, facilitative glucose transporters were expressed in GT1(+/+) and GT1(+/−) embryonic stem cells. GT1(+/−) demonstrated 49 ± 4% reduction of GLUT1 mRNA. This induced a posttranscriptional, GLUT1 compensatory response resulting in 24 ± 4% reduction of GLUT1 protein. GLUT3 was unchanged. GLUT8 and GLUT12 were also expressed and unchanged in GT1(+/−). Stimulation of glycolysis by azide inhibition of oxidative phosphorylation was impaired by 44% in GT1(+/−), with impaired up-regulation of GLUT1 protein. Hypoxia for up to 4 hours led to 201% more apoptosis in GT1(+/−) than in GT1(+/+) controls. Caspase-3 activity was 76% higher in GT1(+/−) versus GT1(+/+) at 2 hours. Heterozygous knockout of GLUT1 led to a partial GLUT1 compensatory response protecting nonstressed cells. However, inhibition of oxidative phosphorylation and hypoxia both exposed their increased susceptibility to these stresses.
Terrestrial effects associated with bright chromospheric eruptions

Over half a century ago Professor C. A. Young called attention to simultaneous occurrence of brightening of H-alpha light in regions of sunspots and certain disturbances of terrestrial magnetism. He surmised that the terrestrial effects were caused by the solar activity and that the active agent connecting the two phenomena was propagated from the Sun to the Earth with the velocity of light. This important observation and suggestion were not taken up by other investigators for many years. Students of the Earth's magnetism found that the great perturbations of terrestrial magnetism—called magnetic storms—were related to solar activity in a statistical sense only. Attempts to associate magnetic storms with central-meridian passages of sunspots indicated a lag of a whole day and more between the solar and terrestrial phenomena.
Management of three toxic Delphinium species based on alkaloid concentrations

A systematic approach to the taxonomic classification of the tall larkspur complex (Delphinium spp.) has been developed and implemented using molecular genetics, plant morphology, and alkaloid profiles, as shown in other papers in this series. This approach supports the classification of three distinct species ( D. glaucum, D. barbeyi and D. occidentale), as the species differ in genetics and toxicity. Toxic alkaloid concentrations over the growing season were integrated with data on diet selection to make management recommendations on a species-specific basis to reduce the risk of poisoning cattle. Alkaloid concentrations in tall larkspurs in excess of 3 mg/g impart moderate or high risk to grazing cattle if sufficient quantities are consumed. D. glaucum is most toxic, with toxic alkaloid concentrations that exceed 3 mg/g throughout the grazing season until late maturity. Cattle should be denied access to dense patches of this species throughout the grazing season until after seed shatter. Concentration of toxic alkaloids in D. barbeyi is highest in vegetative plants, but D. barbeyi is unpalatable to cattle until flowering racemes begin to elongate. We recommend grazing D. barbeyi ranges early in the season when it is not palatable, then removing cattle from early flowering stage through mid-pod stage when cattle are most likely to be poisoned. Cattle can again safely graze D. barbeyi late in the season when the toxic alkaloid concentration typically declines below 3 mg/g. Some populations of D. occidentale and the D. barbeyi× D. occidentale hybrids do not contain toxic alkaloids, and pose little risk of poisoning throughout the year. Toxicity of northern populations of D. occidentale varies from year-to-year for unknown reasons. Cattle
Direct formation of excited singlet states in the electrogenerated chemiluminescence of mixed systems involving N-aryl-2-pyrazolines

Abstract The direct formation of the excited singlet states 1 P * in the electron transfer reaction between the cation radicals of certain N-aryl-2-pyrazolines and the anion radicals of some polycyclic aromatic hydrocarbons, and aryl-substituted oxazoles and oxadiazoles is observed in electrogenerated chemiluminescence studies using measurements of the relative emission intensities and investigations in a magnetic field.
Conditioning the auditory system with continuous vs. interrupted noise of equal acoustic energy: Is either exposure more protective?

Abstract The purpose of this study was to test the hypothesis that differences exist in the amount of protection provided by prior sound conditioning with continuous vs. interrupted, moderate-level noise. Differences were determined by monitoring the changes that occurred in cubic (2 f 1 - f 2 ) distortion product otoacoustic emission (DPOAE) amplitude growth functions subsequent to a traumatizing noise exposure (105 dB SPL, 1.0–2.0 kHz octave band noise presented 24 h per day for 3 days) in guinea pigs which had been conditioned with either continuous (89 dB SPL, 1.0–2.0 kHz octave band noise presented 24 h per day for 11 days) or interrupted noise (95 dB SPL, 1.0–2.0 kHz octave band noise presented on a 6-h `on'/18-h `off' schedule for 11 days) of equal acoustic energy. Results suggest that there are significant differences in the degree of protection provided by prior sound conditioning with the continuous and interrupted schedules of moderate-level noise used in this study. Specifically, the interrupted conditioning protocol afforded some degree of protection against the damaging effects of the traumatizing noise exposure, limited to frequencies above the noise exposure band. Conversely, there was a lack of any consistent and sizable protective effect found across the entire test frequency range for the continuous sound conditioning protocol.
Actin as an energy transducer

When active muscle is stretched, the energy-yielding process for contraction is reversed. In this “reversed contraction”, work is expanded to resynthesize ATP and thus in this process muscle may be classed with mitochondria and chloroplasts. It is argued that actin, the main constituent of the thin filaments, is analogous to the coupling factors of mitochondria and chloroplasts where ATP resynthesis takes place.
Generic features of late-stage crystal growth.

A cell dynamical system model, which realistically incorporates diffusion, is developed to study various aspects of late-stage crystal growth. The algorithm is computationally efficient, allowing the development of complex spatial structures to be studied, and is motivated by renormalization group considerations. We establish the existence of an asymptotic dense branching morphology and relate it to diffusion-limited aggregation. Our findings indicate that the radius of a dense-branching structure grows linearly with time, despite being diffusion controlled, in agreement with experimental observations of the growth of spherulites. A clear morphological transition from kinetic-effect-dominated growth to surface-tension-dominated growth is observed, marked by a difference in the way growth velocity scales with undercooling. We also study the evolution of interfacial instability and find scaling behavior for the interface power spectra, indicating the nonlinear selection of a unique length scale, insensitive to short length-scale fluctuations.
Mitochondrial tolerance to stress impaired in failing heart

Mitochondrial integrity is critical in the maintenance of bioenergetic homeostasis of the myocardium, with oxidative or metabolic challenge to mitochondria precipitating cell injury. In heart failure, where cardiac cells are exposed to elevated stress, mitochondrial vulnerability could contribute to the disease state. However, the mitochondrial response to stress is yet to be established in heart failure. Here, mitochondrial function and structure was evaluated prior and following stress using a transgenic (TG) model of heart failure, generated by cardiac overexpression of the cytokine TNFα. Compared to the wild type, mitochondria from TG failing hearts demonstrated impaired oxidative phosphorylation, mitochondrial DNA damage, reduced mitochondrial creatine kinase activity, abnormal calcium handling, and altered ultrastructure. Under anoxia/reoxygenation or calcium stress, mitochondria from failing hearts suffered exacerbated energetic failure with pronounced cytochrome c release. Thus, mitochondria from TNFα-TG failing hearts demonstrate structural and functional abnormalities, with reduced tolerance to stress manifested by impaired bioenergetics and increased susceptibility to injury. This abnormal vulnerability to stress underscores the impact of mitochondrial dysfunction in the pathobiology of heart failure.
Trypanosoma brucei U insertion and U deletion activities co-purify with an enzymatic editing complex but are differentially optimized

RNA editing, the processing that generates functional mRNAs in trypanosome mitochondria, involves cycles of protein catalyzed reactions that specifically insert or delete U residues. We recently reported purification from Trypanosoma brucei mitochondria of a complex showing seven major polypeptides which exhibits the enzymatic activities inferred in editing and that a pool of fractions of the complex catalyzed U deletion, the minor form of RNA editing in vivo . We now show that U insertion activity, the major form of RNA editing in vivo , chromatographically co-purifies with both U deletion activity and the protein complex. Furthermore, these editing activities co-sediment at approximately 20 S. U insertion does not require a larger, less characterized complex, as has been suggested and could have implied that the editing machinery would not function in a processive manner. We also show that U insertion is optimized at rather different and more exacting reaction conditions than U deletion. By markedly reducing ATP and carrier RNA and increasing UTP and carrier protein relative to standard editing conditions, U insertion activity of the purified fraction is enhanced approximately 100-fold.
A study of catalytic hydrolysis of concentrated ammonia borane solutions

Abstract Ruthenium catalyzed ammonia borane (AB) hydrolysis using aqueous solutions in the range of 5–25 wt% were experimentally studied. The experimental apparatus also included a means for gaseous ammonia sequestration. In addition, the effects of aging on reaction rates and total H2 conversion were investigated using AB solutions that were stored in a limited-air environment for a maximum of 67 days. The present work provides data on total H2 conversion, chemical kinetics, solution density, pH value, byproduct solubility, ammonia generation, and long-term storage stability of concentrated aqueous AB solutions.
E-Books and Ethical Dilemmas for the Academic Reference Librarian

When dealing with e-books, several ethical dilemmas exist as a result of competing professional values. Dilemmas identified and discussed here include challenges related to serving nonaffiliated users, providing high-quality service while respecting intellectual property rights, and balancing the needs of current users with the needs of future generations. Readers would like to have access to all e-books all of the time, with as few restrictions as possible. Librarians would like all of their users (affiliated or nonaffiliated, current or future) to be able to easily use e-books. Librarians also want to recognize the valuable contributions of authors, publishers, and content distributors while safeguarding patron privacy.
Leptin in the Liver: A Toxic or Beneficial Mix?

Although obesity is associated with nonalcoholic fatty liver disease (NAFLD), the causal mechanisms are unclear. In this issue, Imajo et al. (2012) show that, in mice, leptin enhances the effects of bacterial endotoxin, promoting the development of NAFLD.
Synthesis of fluorine-18 labeled rhodamine B: A potential PET myocardial perfusion imaging agent

There is considerable interest in developing an (18)F-labeled PET myocardial perfusion agent. Rhodamine dyes share several properties with (99m)Tc-MIBI, the most commonly used single-photon myocardial perfusion agent, suggesting that an (18)F-labeled rhodamine dye might prove useful for this application. In addition to being lipophilic cations, like (99m)Tc-MIBI, rhodamine dyes are known to accumulate in the myocardium and are substrates for Pgp, the protein implicated in MDR1 multidrug resistance. As the first step in determining whether (18)F-labeled rhodamines might be useful as myocardial perfusion agents for PET, our objective was to develop synthetic methods for preparing the (18)F-labeled compounds so that they could be evaluated in vivo. Rhodamine B was chosen as the prototype compound for development of the synthesis because the ethyl substituents on the amine moieties of rhodamine B protect them from side reactions, thus eliminating the need to include (and subsequently remove) protecting groups. The 2'-[(18)F]fluoroethyl ester of rhodamine B was synthesized by heating rhodamine B lactone with [(18)F]fluoroethyltosylate in acetonitrile at 165 degrees C for 30min using [(18)F]fluoroethyl tosylate, which was prepared by the reaction of ethyleneglycol ditosylate with Kryptofix 2.2.2, K(2)CO(3), and [(18)F]NaF in acetonitrile for 10min at 90 degrees C. The product was purified by semi-preparative HPLC to produce the 2'-[(18)F]fluoroethylester in >97% radiochemical purity with a specific activity of 1.3GBq/mumol, an isolated decay corrected yield of 35%, and a total synthesis time of 90min.
Prion Variants and Species Barriers Among Saccharomyces Ure2 Proteins

As hamster scrapie cannot infect mice, due to sequence differences in their PrP proteins, we find "species barriers" to transmission of the [URE3] prion in Saccharomyces cerevisiae among Ure2 proteins of S. cerevisiae, paradoxus, bayanus, cariocanus, and mikatae on the basis of differences among their Ure2p prion domain sequences. The rapid variation of the N-terminal Ure2p prion domains results in protection against the detrimental effects of infection by a prion, just as the PrP residue 129 Met/Val polymorphism may have arisen to protect humans from the effects of cannibalism. Just as spread of bovine spongiform encephalopathy prion variant is less impaired by species barriers than is sheep scrapie, we find that some [URE3] prion variants are infectious to another yeast species while other variants (with the identical amino acid sequence) are not. The species barrier is thus prion variant dependent as in mammals. [URE3] prion variant characteristics are maintained even on passage through the Ure2p of another species. Ure2p of Saccharomyces castelli has an N-terminal Q/N-rich "prion domain" but does not form prions (in S. cerevisiae) and is not infected with [URE3] from Ure2p of other Saccharomyces. This implies that conservation of its prion domain is not for the purpose of forming prions. Indeed the Ure2p prion domain has been shown to be important, though not essential, for the nitrogen catabolism regulatory role of the protein.
Analysis of Cells

Three methods approaching the analysis of cells are described, with applications. The methods presuppose that the picture of the cells has already been digitized and resides in the memory of a computer. The first method is an ad hoc approach in which intercommunicating programmable cursors are utilized for the detection of boundary and area features. The second method is concerned with an evaluation of the curvatures of boundary segments in relation to the overall shape of the boundary. The third method imbeds the picture in a non-Euclidean coordinate system, preserving as invariants salient features while negating the effect of nonsignificant distortions.
Geometric Mechanics and Aquatic Locomotion through Vortex Shedding

The controlled shedding of vorticity and the resulting development of liftlike forces on control surfaces are fundamental to the hydrodynamics of macroscopic marine animals and underwater vehicles alike. Computational models can reproduce these phenomena with high fidelity, but such models are largely incompatible with analytical methods of model-based feedback control design. Problems in aquatic locomotion have recently attracted attention within the analytical mechanics community, leading to the framing of such problems in the context of Lagrangian systems and geometric nonlinear control, but efforts in this area have been limited to idealized problems in which vortex shedding is conspicuously absent. This paper describes preliminary work to extend the language of geometric mechanics to address the effects of vortex shedding implicitly by modeling the development of liftlike forces on self-propelling bodies.
The effects of dopamine blockade on the human flash electroretinogram

Single-cell electrophysiologic studies have shown that dopamine modulates retinal activity, but its role in human retinal processing is unclear. We investigated the effects of short-term oral administration of dopaminergic receptor blocking agents on the flash electroretinogram in humans. Both chlorpromazine (25 and 50 mg) and fluphenazine (1 and 2 mg) significantly reduced electroretinogram b-wave amplitudes and also selectively reduced the amplitude of the first oscillatory potential. Implicit times were not altered. Metoclopramide (10 and 20 mg) had no effect on any electroretinographic variable. Our study indicates that dopamine receptor blocking agents with both D-1 and D-2 receptor affinities reduce the amplitude of the electroretinogram in humans.
The versatile steroid nucleus: Design and synthesis of a peptidomimetic employing this novel scaffold.

Abstract The design and synthesis of peptidomimetic 1 employing the novel cyclopentanoperhydrophenanthrene skeleton is described. The large body of steroid literature allows for the introduction of diverse peptidal side chains with precise regio- and stereoselective control. Compound 1 binds to the fibrinogen receptor on blood platelets (GP IIb/IIIa), for which it was designed, with an IC50 of ca. 100 μM.
Context-sensitive ranking for document retrieval

We study the problem of context-sensitive ranking for document retrieval, where a context is defined as a sub-collection of documents, and is specified by queries provided by domain-interested users. The motivation of context-sensitive search is that the ranking of the same keyword query generally depends on the context. The reason is that the underlying keyword statistics differ significantly from one context to another. The query evaluation challenge is the computation of keyword statistics at runtime, which involves expensive online aggregations. We appropriately leverage and extend materialized view research in order to deliver algorithms and data structures that evaluate context-sensitive queries efficiently. Specifically, a number of views are selected and materialized, each corresponding to one or more large contexts. Materialized views are used at query time to compute statistics which are used to compute ranking scores. Experimental results show that the context-sensitive ranking generally improves the ranking quality, while our materialized view-based technique improves the query efficiency.
Substrate specificities in class A β-lactamases: Preference for penams vs. cephams. The role of residues 237

Site saturation mutagenesis has been carried out at Ala-237 in RTEM-1 β-lactamase to assess the role of this site in modulating differences in specificity of β-lactamases for penams vs. cephams as substrates. (An Ala-237 Thr mutation had previously been shown to increase activity on cephems by about 30–80%.^(1,2)) Screening of all 19 possibles mutants on penams and cephems revealed the even more active Ala-237 Asn mutant. Detailed kinnetic analysis showns that this mutant has about four times the activity toward cephalothin and cephalosporin C as the wild-type enzyme. Both mutations reduce the activity toward penams to about 10% that of RETM-1 β-lactamase and lower by about 5°C the tempreature at which the enzyme denatures. Functional properties of the other mutants have also been surveyed. The most intresting aspect of these results is that two quite disparate amino acids, theronine and asparagine, when intorduced for Ala-237, cause such similar changes in enzyme specificity while more similar residues do not alter the catalytic properties of the enzyme to such a significant degree.
Landau levels in graphite intercalation compounds

Abstract The first calculation of the magnetic energy level structure of a graphite intercalation compound is presented. The calculational technique exploits the staging symmetry through the k z -axis zone folding of the magnetic energy levels of the graphite π-bands. The results are applicable to the interpretation of the magnetoreflection and de Haas-van Alphen type experiments in intercalated graphite.
Deep inelastic processes with hadronic initial states

The application to hadron-hadron collisions of what is presumed to have been learned from elastic and inelastic electron scattering is discussed. Two subjects which perhaps typify the applications of deep inelastic physics to hadronic reactions: pp ..-->.. ..mu../sup +/..mu../sup -/(Q/sup 2/) + anything at high energy and large Q/sup 2/--from both the parton model and light cone viewpoint and Parton models of large angle elastic scattering, especially the interchange model of Blankenbecler, Brodsky, and Gunion are emphasized. Also covered briefly is inclusive production of hadrons at high momenta transverse to the beams at ISR. (JFP)
Complexes of oxovanadium(IV)

Abstract The preparation and partial characterization of a number of new complexes of the oxovanadium(IV) ion are reported. Cationic, neutral and anionic complexes in which the vanadium(IV) is either five- or six-co-ordinated are included. Conductivity studies have generally allowed the assignment of groups to the first co-ordination sphere and the presence of the vanadium-oxygen multiple bond in each compound has been established by infrared spectra.
Gender and agricultural productivity: implications of the Farm Input Subsidy Program in Malawi

Alleviating gender differences in agricultural productivity is vital for poverty reduction. While numerous studies suggest that gender differences in agricultural productivity are a result of female farmers having limited access to resources, few studies investigate the role of agricultural interventions in alleviating the constraints to input use and subsequently the gender gap in productivity. This study investigates whether there are gendered gains in agricultural productivity from participating in an input subsidy program and if these gains help reduce the gender gap. Using nationally representative data that is disaggregated at the plot level, this study analyzes the large-scale voucher-based Farm Input Subsidy Program in Malawi. Focusing on the total value of output per hectare, relationships are identified using weighted estimators, where the weights are constructed from propensity scores, and spatial fixed effects, to address the unobservable factors that may confound the relationship between program participation and productivity. The findings suggest that participation in the program improves agricultural productivity for both male and female farmers but it does not provide disproportionate help to female famers to overcome gender disparities in agricultural productivity. This suggests that female farmers face additional constraints to productivity apart from nonlabor input use.
Estimation of accessibility of DNA in chromatin from fluorescence measurements of electronic excitation energy transfer.

EUKARYOTIC DNA is complexed with proteins which influence its conformation, stability and function1,2. Attempts to correlate the chemical and biological properties of chromatin have focused on the coverage of DNA by chromosomal proteins3–8. As much as 50% of the DNA in chromatin is accessible to precipitants (such as basic dyes or polylysine)3–6 or to limiting nucleolytic digestion3,4,6–8, suggesting a model of segmental DNA accessibility in chromatin resembling a frayed telephone wire. Digestion extensively alters chromatin structure, however, and the results of experiments involving precipitation or digestion may be influenced by processes associated with the aggregation phenomena serving as experimental endpoints. We have used an alternative approach to characterise DNA accessibility in chromatin using the transfer of electronic excitation energy between pairs of fluorescent dyes bound to chromatin at low ratios of dye to phosphate. The results suggest that at least one-third of the DNA in chromatin retains a high affinity for basic dyes. The exclusion of dyes or other molecules9 from portions of chromatin may, however, depend on the conformation of chromatin as well as on the protein–DNA stoichiometry.
The treatment of failed laparoscopy using open laparoscopy

Abstract There are over 300,000 laparoscopies done each year in the United States, and about 60,000 in England. “Failed laparoscopies” in which the procedure cannot be accomplished, has variously been reported in 0.043–4.3/1000 cases. A reasonable estimate of failed laparoscopy of 0.75% suggest that up to 2250 cases of “failed laparoscopy” occurs each year in the USA and 450 in UK. The translation of such failures into the personal experience of patients and the overall cost is staggering despite the fact that failures are not common. Three cases of “failed laparoscopy” in which the procedure was easily completed by open laparoscopy are reported and discussed. Familiarity with the techniques of open laparoscopy could virtually eliminate the incidence of failed laparoscopies.
Low-Noise Cooled GASFET Amplifiers

Measurements of the noise characteristics of a variety of gallium-arsenide field-effect transistors at a frequency of 5 GHz and temperatures of 300 K to 20 K are presented. For one transistor type detailed measurements of dc parameters, small-signal parameters, and all noise parameters (T/sub min/, R/sub opt/, X/sub opt/ g/sub n/) are made over this temperature range. The results are compared with the theory of Pucel, Haus and Statz modified to include the temperature variation. Several low-noise ampifiers are described including one with a noise temperature of 20 K over a 500-MHz bandwidth. A theoretical analysis of the thermal conduction at cryogenic temperatures in a typical packaged transistor is included.
Are feelings of responsibility to limit the sexual transmission of HIV associated with safer sex among HIV-positive injection drug users?

We developed a scale among HIV-positive injection drug users (IDUs) to measure self-perceived responsibility to limit HIV transmission during sex. We describe the characteristics of HIV-positive IDUs (n = 1114, 62% male, HIV-positive for 9 years on average) who felt responsible for protecting their sexual partners from HIV and evaluated whether such feelings were associated with safer sexual practices. Using this scale (Cronbach a = 0.83) and audio computer-assisted self-interviewing technology, 75% of this sample felt responsible for protecting their sexual partners from HIV In cross-sectional multivariate analysis, HIV-positive IDUs who felt responsible were those with greater HIV knowledge (adjusted odds ratio [95% confidence interval]: 1.74 [1.26 to 2.40]), perceived social support (1.77 [1.28 to 2.44]), self-efficacy for safely injecting (1.41 [1.02 to 1.94]), and self-efficacy for using condoms (1.92 [1.38 to 2.68]). Feeling responsible was associated with having relatively fewer sex partners (<10 vs.≥10, 0.57 [0.34 to 0.96]) and a lower odds of unprotected sex (0.63 [0.45 to 0.89]) but was not associated with safer injection practices. Feelings of responsibility did not vary by demographic characteristics, suggesting that prevention messages that encourage HIV-positive people to play a role in curbing HIV transmission may be acceptable to many HIV-positive IDUs. Working with HIV-positive IDUs to increase or reinforce feelings of responsibility may reduce the sexual transmission of HIV.
Shape of hexagonal hydrostatic menisci

A numerical method is implemented for computing the shape of an infinite, hexagonal, doubly periodic, hydrostatic meniscus originating from contact lines whose projections in the horizontal plane are circles. The contact lines themselves may lie on vertical cylinders or spherical objects. The Laplace–Young equation determining the meniscus shape is solved by a finite-difference method in orthogonal curvilinear coordinates generated by conformal mapping. The elevation of the contact lines is either prescribed or computed as part of the solution to ensure a specified contact angle. The results illustrate that the contact line spacing has an important effect on the contact angle or contact line distribution. Meniscus shapes exist only for a limited range of pressure differences between the upper and lower fluid that depend on the capillary length. Copyright © 2009 John Wiley & Sons, Ltd.
The evolution of load/unload technology

Load/unload (L/UL) has recently replaced contact start-stop (CSS) technology in major segments of the hard disk-drive (HDD) industry. Although L/UL has existed since the earliest HDDs, recent implementations use fixed ramp L/UL systems, which are considerably simpler than earlier versions. L/UL offers multiple advantages over CSS, including practically unlimited start-stop cycles and improved shock robustness. However, disk damage can occur in L/UL drives due to head-disk contacts, and a variety of parameters including vertical L/UL speed and slider corner radius should be optimized to minimize damage. Tight control of key tolerances is essential to maximize available disk real estate and minimize the required disk spacing to accommodate L/UL. Power-off retract systems for L/UL must produce higher retract torque than those for CSS designs, leading to new retract circuit designs.
Polycrystalline secondary ferroics

Abstract Domain walls in secondary ferroics can be displaced by electric fields, magnetic fields, mechanical stresses, or by some combination of the three. The expected physical properties of fully “poled” secondary ferroics are calculated and compared with those of the unpoled polycrystalline material, and with available experimental evidence. The effects of poling are most obvious for null properties such as piezoelectricity and magnetoelectricity, which depend entirely on domain alignment. Experiments on NH4Cl provide the first demonstration of ferroelastoelectric “poling” in a polycrystalline material; piezoelectricity appears after annealing at −30°C in parallel electric fields and mechanical stress. Other examples of “poled” polycrystalline secondary ferroics include ferromagnetoelectric Cr2O3, ferrobielastic SiO2, and ferrobimagnetic MnO.
Induction of G2 arrest and binding to cyclophilin A are independent phenotypes of human immunodeficiency virus type 1 Vpr.

Cyclophilin A (CypA) is a member of a family of cellular proteins that share a peptidyl prolyl cis-trans isomerase (PPIase) activity. CypA was previously reported to be required for the biochemical stability and function (specifically, induction of G2 arrest) of the human immunodeficiency virus type 1 (HIV-1) protein R (Vpr). In the present study, we examine the role of the Vpr-CypA interaction on Vpr-induced G2 arrest. We find that Vpr coimmunoprecipitates with CypA and that this interaction is disrupted by substitution of proline-35 of Vpr as well as incubation with the CypA inhibitor cyclosporine A (CsA). Surprisingly, the presence of CypA or its binding to Vpr is dispensable for the ability of Vpr to induce G2 arrest. Vpr expression in CypA−/− cells leads to induction of G2 arrest in a manner that is indistinguishable from that in CypA+ cells. CsA abolished CypA-Vpr binding but had no effect on induction of G2 arrest or Vpr steady-state levels. In view of these results, we propose that the interaction with CypA is independent of the ability of Vpr to induce cell cycle arrest. The interaction between Vpr and CypA is intriguing, and further studies should examine its potential effects on other functions of Vpr.
Systematics of the spider genera Mallos and Mexitlia (Araneae, Dictynidae)

This systematic study recognizes and describes 14 species of the genus Mallos O. Pickard-Cambridge, 1902 and three species of the genus Mexitlia Lehtinen, 1967. Three species of Mallos—Mallos gertschi, Mallos chamberlini and Mallos macrolirus—and one species of Mexitlia—Mexitlia altima—are newly described. Mallos ghiggi (Caporiacco, 1938) is considered a synonym of Mexitlia grandis (O. PickardCambridge, 1896). Mexitlia grandis is considered the senior synonym of Mexitlia avara (Banks, 1898). Two species, Mallos flavovittatus (Keyserling, 1880) and Mallos nigrescens (Caporiacco, 1955) are removed from Mallos. The males of Mallos kraussi Gertsch, 1946 and Mallos blandus Chamberlin and Gertsch 1958, are described for the first time. A cladistic analysis based on 26 morphological characters produced a cladogram that supports the monophyly of Mallos and the validity of Mexitlia. This cladogram presents a phylogenetic framework for considering the evolution of social behaviour in Mallos.
Scheduling parity checks for increased throughput in early-termination, layered decoding of QC-LDPC codes on a stream processor

A stream processor is a power-efficient, high-level-language programmable option for embedded applications that are computation intensive and admit high levels of data parallelism. Many signal-processing algorithms for communications are well matched to stream-processor architectures, including partially parallel implementations of layered decoding algorithms such as the turbo-decoding message-passing (TDMP) algorithm. Communication among clusters of functional units in the stream processor impose a latency cost during both the message-passing phase and the parity-check phase of the TDMP algorithm with early termination; the inter-cluster communications latency is a significant factor in limiting the throughput of the decoder. We consider two modifications of the schedule for the TDMP algorithm with early termination; each halves the communication required between functional-unit clusters of the stream processor in each iteration. We show that these can provide a substantial increase in the information throughput of the decoder without increasing the probability of error.
Amount but Not Pattern of Protective Sensory Stimulation Alters Recovery After Permanent Middle Cerebral Artery Occlusion

Background and Purpose—Using a rodent model of ischemia (permanent middle cerebral artery occlusion), our laboratory previously demonstrated that 4.27 minutes of patterned single-whisker stimulation delivered over 120 minutes can fully protect from impending damage when initiated within 2 hours of permanent middle cerebral artery occlusion (“early”). When initiated 3 hours postpermanent middle cerebral artery occlusion (“late”), stimulation resulted in irreversible damage. Here we investigate the effect of altering pattern, distribution, or amount of stimulation in this model. Methods—We assessed the cortex using functional imaging and histological analysis with altered stimulation treatment protocols. In 2 groups of animals we administered the same number of whisker deflections but in a random rather than patterned fashion distributed either over 120 minutes or condensed into 10 minutes postpermanent middle cerebral artery occlusion. We also tested increased (full-whisker array versus single-whisker) sti...
Reduction of the secondary neutron dose in passively scattered proton radiotherapy, using an optimized pre-collimator/collimator

Proton radiotherapy represents a potential major advance in cancer therapy. Most current proton beams are spread out to cover the tumor using passive scattering and collimation, resulting in an extra whole-body high-energy neutron dose, primarily from proton interactions with the final collimator. There is considerable uncertainty as to the carcinogenic potential of low doses of high-energy neutrons, and thus we investigate whether this neutron dose can be significantly reduced without major modifications to passively scattered proton beam lines. Our goal is to optimize the design features of a patient-specific collimator or pre-collimator/collimator assembly. There are a number of often contradictory design features, in terms of geometry and material, involved in an optimal design. For example, plastic or hybrid plastic/metal collimators have a number of advantages. We quantify these design issues, and investigate the practical balances that can be achieved to significantly reduce the neutron dose without major alterations to the beamline design or function. Given that the majority of proton therapy treatments, at least for the next few years, will use passive scattering techniques, reducing the associated neutron-related risks by simple modifications of the collimator assembly design is a desirable goal.
Autoregressive Models for Capture‐Recapture Data: A Bayesian Approach

In this article, we incorporate an autoregressive time-series framework into models for animal survival using capture-recapture data. Researchers modeling animal survival probabilities as the realization of a random process have typically considered survival to be independent from one time period to the next. This may not be realistic for some populations. Using a Gibbs sampling approach, we can estimate covariate coefficients and autoregressive parameters for survival models. The procedure is illustrated with a waterfowl band recovery dataset for northern pintails (Anas acuta). The analysis shows that the second lag autoregressive coefficient is significantly less than 0, suggesting that there is a triennial relationship between survival probabilities and emphasizing that modeling survival rates as independent random variables may be unrealistic in some cases. Software to implement the methodology is available at no charge on the Internet.
Snf1 Promotes Phosphorylation of the α Subunit of Eukaryotic Translation Initiation Factor 2 by Activating Gcn2 and Inhibiting Phosphatases Glc7 and Sit4

Snf1 is the ortholog of mammalian AMP-activated kinase and is responsible for activation of glucose-repressed genes at low glucose levels in budding yeast. We show that Snf1 promotes the formation of phosphorylated alpha subunit of eukaryotic translation initiation factor 2 (eIF2alpha-P), a regulator of general and gene-specific translation, by stimulating the function of eIF2alpha kinase Gcn2 during histidine starvation of glucose-grown cells. Thus, eliminating Snf1 or mutating its activation loop lowers Gcn2 kinase activity, reducing the autophosphorylation of Thr-882 in the Gcn2 activation loop, and decreases eIF2alpha-P levels in starved cells. Consistently, eliminating Reg1, a negative regulator of Snf1, provokes Snf1-dependent hyperphosphorylation of both Thr-882 and eIF2alpha. Interestingly, Snf1 also promotes eIF2alpha phosphorylation in the nonpreferred carbon source galactose, but this occurs by inhibition of protein phosphatase 1alpha (PP1alpha; Glc7) and the PP2A-like enzyme Sit4, rather than activation of Gcn2. Both Glc7 and Sit4 physically interact with eIF2alpha in cell extracts, supporting their direct roles as eIF2alpha phosphatases. Our results show that Snf1 modulates the level of eIF2alpha phosphorylation by different mechanisms, depending on the kind of nutrient deprivation existing in cells.
Nemitsky's operators and lower closure theorems

This paper focuses on certain analytic criteria given by the authors in earlier works, for the geometric property of upper semicontinuity of set-valued functions, used in the proofs of lower closure theorems, and hence in existence theory. In particular, it is observed that, under Filippov-type condition (namely, when the set of controls is bounded in measure or in norm), mere Caratheodory-type continuity of the relevant functionsf is sufficient to guarantee a weak form of property (Q), and in turn the lower closure theorems.
Early Growth Response-1 Promotes Atherogenesis: Mice Deficient in Early Growth Response-1 and Apolipoprotein E Display Decreased Atherosclerosis and Vascular Inflammation

Early growth response-1 (Egr-1) regulates expression of proinflammatory and procoagulant genes in acute cell stress. Experimental evidence suggested that Egr-1 transcripts were upregulated in human atherosclerotic plaques versus adjacent unaffected tissue. To test the impact of Egr-1 in chronic vascular stress, we examined its role in a murine model of atherosclerosis. Real-time PCR analysis of aortae retrieved from apoE-/- mice demonstrated increased Egr-1 transcripts in an age-dependent manner, compared with aortae retrieved from C57BL/6 control animals. Therefore, homozygous Egr-1-/- mice were bred into the apoE-/- background. Homozygous double-knockout mice (Egr-1-/-/apoE-/-) in the C57BL/6 background were maintained on normal chow diet. At age 14 and 24 weeks, atherosclerotic lesion area and complexity at the aortic root were strikingly decreased in mice deficient in both Egr-1 and apoE compared with mice deficient in apoE alone. In parallel, transcripts for genes regulating the inflammatory/prothrombotic response were diminished in Egr-1-/-/apoE-/- aortae versus apoE-/-. In vitro, oxidized low-density lipoprotein (OxLDL), a key factor inciting atherogenic mechanisms in the vasculature, upregulated Egr-1 expression in monocytes via the MEK-ERK1/2 pathway. We conclude that Egr-1 broadly regulates expression of molecules critically linked to atherogenesis and lesion progression.
C-ARM DISTORTION CORRECTION USING PATIENT CT AS A FIDUCIAL

X-ray imaging is an extensively used intra-operative imaging modality because of its low cost and portability. These images have to be corrected for geometric distortion in order to use them for quantitative analysis. Current distortion correction techniques, which use a grid pattern phantom, are not user friendly, for example the phantom interferes with the patient anatomy being imaged. We present a novel method to estimate the c-arm distortion parameters along with the patient pose using patient CT as a fiducial. This method could be very useful in applications such as 3D reconstruction and surgical navigation. In this method, we characterize the c-arm distortion patterns statistically using principal component analysis. The distortion correction method optimizes the distortion parameters by comparing the fluoroscopic images and the projections of the registered patient CT. Our simulation experiments show that the distortion parameters can be recovered up to an average accuracy of 0.5117 mm with a pose error of about 0.1692 mm in translation, 0.2112 deg in rotation
Automata-theoretic techniques for image generation and compression

In this paper, the representation, generation and inference of images using automata theoretic techniques is investigated. It is shown that highly complex images, including “fractal” (self-similar) images, can be manipulated by the application of these techniques. Languages and relations over some alphabet are interpreted as images by treating strings as rational coordinates. In particular, the rational relations, specified by rational expressions, are considered. It is shown how texture of an image can be defined by probabilistic finite generators. Iterative generators are also considered.
Early Language Learning and Literacy: Neuroscience Implications for Education.

The last decade has produced an explosion in neuroscience research examining young children’s early processing of language that has implications for education. Noninvasive, safe functional brain measurements have now been proven feasible for use with children starting at birth. In the arena of language, the neural signatures of learning can be documented at a remarkably early point in development, and these early measures predict performance in children’s language and pre-reading abilities in the second, third, and fifth year of life, a finding with theoretical and educational import. There is evidence that children’s early mastery of language requires learning in a social context, and this finding also has important implications for education. Evidence relating socio-economic status (SES) to brain function for language suggests that SES should be considered a proxy for the opportunity to learn and that the complexity of language input is a significant factor in developing brain areas related to language. The data indicate that the opportunity to learn from complex stimuli and events are vital early in life, and that success in school begins in infancy.