cssi/SciSciGPT-SciSciNet huggingface dataset:
Stimulation strategies for selective activation of retinal ganglion cell soma and threshold reduction.

Objective Retinal prosthetic implants restore partial vision to patients blinded due to outer retinal degeneration, using a camera-guided multielectrode array (MEA) that electrically stimulates surviving retinal neurons. Commercial epi-retinal prostheses use millisecond-scale charge-balanced, symmetric, cathodic-first biphasic pulses to depolarize retinal ganglion cells (RGCs) and bipolar cells (BCs), frequently creating oblong perceptions of light related to axonal activation of RGCs. Stimulation strategies that avoid axonal stimulation and decrease the threshold of targeted neurons may significantly improve prosthetic vision in terms of spatial resolution and power efficiency. Approach We developed a virus-transduced genetically encoded calcium indicator (GECI) GCaMP6f and microscopy platform for calcium imaging to record the neural activity from RGCs at single-cell resolution in wholemount retinas. Multiple stimulation paradigms were applied through a microelectrode array (MEA) with transparent indium tin oxide electrodes. The evoked neuronal activities were converted to corresponding 2D calcium imaging transient pattern and spatial threshold map to identify the ideal focal response which corresponds to optimal percept in patient. Main results The proposed optical system with GCaMP6f is capable of recording from population of mouse RGCs in real time during electrical stimulation with precise location information relative to the stimulation sites. Optimal duration and phase order of pulse were identified to avoid axonal stimulation and selectively activate targeted RGC somas, without requiring a significant increase in stimulation charge. Additionally, we show that reduced stimulus threshold can be achieved with the special design of asymmetric anodic-first pulse. Significance Our findings support the possibility of manipulating the responses of RGCs through varying the stimulation waveform. Focal response can be achieved with relative short duration (⩽120 μs) pulses, and can be improved by reversing the standard phase order. The RGCs threshold can be significantly reduced by 33.3%-50% in terms of charge through applying hyperpolarizing pre-pulses with a 20:1 ratio (pre-pulse:stimulus pulse). The results support the future retinal prosthesis design that potentially forms more ideal shape perception with higher spatial resolution and power efficiency.
Kernel-Based Human-Dynamics Inversion for Precision Robot Motion-Primitives

Learning motion primitives from demonstration requires the human demonstrator to effectively relay the task intent to the robot controller. When the task intent is not reflected sufficiently by the demonstration, multiple iterations are required to recover the underlying intent of the demonstrations. However, a large number of iterations can be expensive and might not be practical for each new task. A challenge is that human-in-the-loop demonstrations can be affected by the human motor dynamics (e.g., from visual observation to hand motion), which can lead to differences between the demonstration and intent. The main contribution of this article is to correct for the human motor dynamics and infer the intended action (motion primitive) from the human demonstrations. The proposed approach uses a kernel-based regression approach to learn the inverse human-dynamics response. These models are then used to correct for human-motor-dynamics and infer the intent of the human-in-the-loop demonstrator. Experimental validation is performed with an assisted teleoperation setup where the underlying intent is specified using an augmented reality display. Results indicate that the proposed approach leads to more precise intent estimation as compared to the actual human demonstrations.
Geologic variability underlying stream catchment areas correlates with fish otolith microchemistry across disparate glacial till depths

Abstract A primary application of otolith microchemistry is distinguishing natal origins of individual fish within a mixed-stock fishery. Stocks must be distinguishable according to stock-specific microchemistry patterns, with accurate stock assignment contingent upon microchemistry assessment of all sources contributing to the mixed-stock fishery. However, otolith microchemistry signatures of individual fish, upon which classification models are built, likely represent only a portion of the variability that exists for the stocks corresponding to each natal source. To statistically infer expected otolith microchemistry patterns among unsampled catchment areas proximal to sampled areas, we tested the hypothesis that variation in catchment geology among 35 stream sites across the Lake Michigan basin is correlated with the variation in otolith microchemistry signatures of age-0 steelhead collected at those sites. Matrices of Mahalanobis distances between all pairs of individual fish were calculated for each of the following: (1) assignment scores from discriminant function analysis of the variation among sites based on otolith microchemistry, and (2) the geology underlying the catchments upstream of each of the sites where fish were sampled. Based on Mantel tests, these matrices were found to be significantly correlated, indicating that age-0 steelhead that exhibit greater differences in otolith microchemistry signatures tended to come from sites exhibiting greater differences in catchment geology. Surficial geology alone was more correlated with otolith microchemistry than bedrock age, bedrock lithology, or any combinations of the three geological datasets. The significant relationship between geology and otolith microchemistry, although weak, supports tenuous hydrologic and geologic bases for delineating natal source geographic boundaries.
Photothermal Control over the Mechanical and Physical Properties of Polydimethylsiloxane

Though it is known that the photothermal effect of nanoparticles can be used to greatly increase the rate of polymer curing, at present, little is known about how the parameters of photothermal curing affect the desirable chemical and physical properties of the cured polymer. We report the swelling, gel fraction, and Young’s modulus for the thermoset polydimethylsiloxane cured under a variety of photothermal and traditional conditions. We find that all of these properties can be tuned via the intensity of light and propose that the crosslink density within the thermoset decreases with increasing intensity of light during curing.
Hydroxamate formation by anthranilate synthetase of Escherichia coli K12

HO' H /H2 0 \ I dOOH chorismic acid anthranilic acid (Gibson and Gibson, 1964; Somerville, unpublished results). In Escherichia coli the catalytically active species is a protein complex formed by aggregation of the products of the E and D genes of the tryptophan operon (Ito and Yanofsky, 1966). Anthranilate synthetase is one of a class of amidotransferase enzymes where L-glutamine serves as the physiological nitrogen donor (Meister, 1962). Ammonia, added at relatively high concentrations, will serve as the nitrogen source for anthranilate formation in vitro (Srinivasan and Rivera, 1963; Edwards et al., -1964). Ammonia is also active in vivo (Gibson et al., 1967). -Although the overall reaction leading from chorismate to anthranilate has been studied (Baker and Crawford, 19671, neither the structures of possible intermediates between chorismate and
ICME Approach to Determining Critical Pore Size of IN718 Produced by Selective Laser Melting

A degree of porosity is expected in additively manufactured (AM) materials. To aid in the qualification of AM materials, the smallest pore size that results in a debit in the fatigue performance is quantified. In the work presented herein, crystal plasticity simulations are used to identify the stress concentration around pores of various sizes, revealing that a single 20-μm pore or two 10-μm pores (with centers spaced 15 μm apart) localize stress at the pore, as opposed to elsewhere in the microstructure. In situ microtomography and far-field high-energy x-ray diffraction microscopy were used to identify crack formation and the evolution of the grain-level micromechanical fields during cyclic loading. Eighteen cracks were observed (15 at pores, 3 at the surface) at highly stressed grains in a sample, although most did not propagate. The dominant crack was seen to originate from the free surface, which is rationalized by fracture mechanics.
Comfort positioning during procedures in pediatric dermatology

Procedures performed in pediatric dermatology can often be painful or distressing for patients and their families. Comfort positioning, which involves sitting the child upright, immobilized and held by a caretaker, is one strategy that may be employed in this setting; this measure has been shown to reduce patient distress, improve cooperation and give caretakers a more active role in the procedure. We demonstrate several positions of comfort for dermatologic procedures involving the arm, cheek, back and leg of a young child.
Effects of Processing Methods on fNIRS Signals Assessed During Active Walking Tasks in Older Adults

Functional near infrared spectroscopy (fNIRS) is a noninvasive optics-based neuroimaging modality successfully applied to real-life settings. The technology uses light in the near infrared range (650-950nm) to track changes in oxygenated (HbO2) and deoxygenated hemoglobin (Hb) obtained from measured light intensity using light-tissue interaction principles. fNIRS data processing involves artifact removal and hemodynamic signal conversion using modified Beer-Lambert law (MBLL) to obtain Hb and HbO2, reliably. fNIRS signals can get contaminated by various noise sources of physiological and non-physiological origins. Various algorithms have been proposed for the elimination of artifacts from frequency selective filters to blind source separation methods. Hemodynamic signal extraction using raw intensity measurements at multiple wavelengths based on MBLL usually involves apriori knowledge of certain conversion parameters such as molar extinction coefficients ( $\varepsilon$ ) and differential path length factor (DPF). Different sets of conversion parameters dependent upon wavelength, chromophores, and age have been reported. Variation in processing algorithms and parameters can cause differences in Hb and HbO2 extraction which can in turn change study outcomes. Using fNIRS, we have previously shown significant increases in oxygenation in the prefrontal cortex from Single-Task-Walking (STW) to Dual-task-Walking (DTW) conditions in older adults due to greater cognitive demands inherent in the latter condition. In the current study, we re-analyzed our data and determined that although using different conversion parameters i.e. $\varepsilon $ and age dependent DPF and filter cut-off frequencies at 0.14 and 0.08Hz including those designed to remove confounding effects of Mayer waves had caused some linear increases or decreases on the extracted Hb and HbO2 signals, those effects were minimal in task related comparisons and hence, the overall study outcomes.
Clinical analysis of invasive fungal infection in 24 cases of newborn infants

Objective To analyze the clinical features,risk factors,treatment and prognosis of invasive fungal infection.Methods The clinical data of 24 infants with invasive fungal infection during January 2010and December 2011 from Zhengzhou children's hospital were retrospectively concluded.Results The high risk factors of invasive fungal infection in newborn infants include preterm,low birthweight,mechanical ventilation,inserting catheter,broad-spectrum antibiotic.The common clinical presentations were fever,lethargy,tachypnea or apnea more than before,abdominal distension,feeding intolerance and thrombocytopenia.The candia albicans was the major pathogen.Early-started the treatment of fluconazole can improved the prognosis.Conclusions The clinical presentations of invasive fungal infection are always nonspecific.Fluconazole appears to be effective.Early-started antifungal therapy can improve the prognosis. Key words: Newborn infants; Invasive fungal infection; High risk factor
Cross-sectional analysis of US scope of practice laws and employed physician assistants.

Objective This study examined if the variation in physician assistant (PA) state scope of practice (SOP) laws across states are associated with number of employed PAs, PA demographics and PA/population ratio per state. The hypothesis was that less restrictive SOP laws will increase the demand for PAs and the number of PAs in a state. Design Retrospective cross-sectional analysis at three time points: 1998, 2008, 2017. Setting Fifty states and the District of Columbia. Participants Employed PAs in 1998, 2008, 2017. Methods SOP laws were categorised as permissive, average and restrictive. Three national datasets were combined to allow for descriptive analysis of employed PAs by year and SOP categories. We used linear predictive models to generate and compare PA/population ratio least square means by SOP categories for each year. Models were adjusted for percent female PA and PAs mean age. Results There was a median PA/population ratio of 23 per 100 000 population in 1998 and 33 in 2017. A heterogeneous expansion of SOP laws was seen with 17 states defined as super expanders while 15 were never adopters. In 2017, comparing restrictive to permissive states showed that in adjusted models permissive SOP laws were associated with 11.7 (p .03) increase in ratio of employed PAs per 100 000 population, demonstrating that states with permissive SOP laws have an increased PA density. Conclusions There has been steady growth in the mean PA/population ratio since the turn of the century. At the same time, PA SOP laws in the USA have expanded, with just 10 states remaining in the restrictive category. Permissive SOP laws are associated with an increase in the ratio of employed PAs per state population. As states work to meet the projected physician need, SOP expansion may be an important policy consideration to increase the PA workforce.
The role of fuel cells in port microgrids to support sustainable goods movement

Abstract Facilities such as ports that are associated with goods movement face challenges in managing energy requirements including growing demands, maintaining economic competitiveness, increasing efficiencies of operation, and improving the resiliency, reliability, and security of the energy supply. Furthermore, ports face pressure to meet environmental goals including reducing the emissions of both pollutants and greenhouse gases and increasing the levels of renewable sources. Within this framework, many port operators are pursuing the development of microgrids supported by self-generation including fuel cell systems. Given the breadth of energy requirements of ports, the range of fuel cell applications is an attractive resource for stationary power generation, motive power and fuel generation, and backup/auxiliary power in concert with base load power. This work involves a review of the literature, from a technical perspective, to assess microgrids and fuel cell systems at ports including comparison with combustion-based power distributed generation sources. Additionally, novel simulations are presented to provide insight into economic and emission considerations associated with fuel cell deployment in critical facilities. Important distinctions of fuel cells for ports include flexibility of size and fuel, low to negligible emissions, capability to operate in grid-forming mode, and high electric-only efficiencies. While combined cooling, heating, and power improves performance and should be pursued, the mismatch in port electrical and thermal loads is a potential barrier and increases the importance of high electric-only efficiencies of fuel cells. Tri-generation systems have the potential to maximize benefits with the production of hydrogen along with electricity and, if needed, heat.
Early Events in Herpes Simplex Virus Infection: a Radioautographic Study

The early events in herpes simplex virus infection were studied by means of radio-autography. The virus was rapidly taken up by the host cells and uncoated. Viral deoxyribonucleic acid (DNA) reached the nuclear sites of replication in 15 to 30 min after infection. The viral DNA occasionally associated with chromosomes or condensed chromatin but was more frequently found to be randomly distributed. Viral progeny appeared 3 hr after infection. These particles did not show any particular spatial relationship to the parental DNA. The morphological latent period lasted 2.5 hr. Images
Spitzer’s View of Galaxies in the High-Redshift Universe

One of the most important observations made by the Spitzer Space Telescope has been the detection of luminous galaxies back to the era of reionization (z ~ 8), when the universe was less than 700 million years old. The key advance made by Spitzer imaging isthe ability, for the first time, to sample the redshifted rest-frame visible light of these galaxies. When combined with broadband multi-wavelength data, Spitzer observations can be fit to stellar population synthesis models to determine the spectral energy distribution of these galaxies and to constrain their stellar masses and ages and their star formation histories. As a result, there is evidence that most of the stellar mass of these galaxies formed at even higher redshifts (z > 10 to 12) and that asignificant number of galaxies should exist in this region.Searches for galaxies at z ~ 9 to 10 continue. Spitzer observations of massive lensing clusters have also played a pivotal role in this study. The first IRAC detection of a z >6 galaxy came from such observations. Since most of these results were obtained with Spitzer/IRAC 3.6/4.5 μm bands, the Spitzer Warm Mission, when combined with future HST/WFC3 observations, will provide a unique opportunity to obtain the first complete census of the assembly of stellar mass as a function of cosmic time back to the era of reionization, yielding unique information on galaxy formation in the early universe.
169 How insulin binds: structure of a micro-receptor complex and implications for analog design

The discovery of insulin in 1921 represented a landmark in molecular medicine and led to extensive investigation of the structure and function of this globular protein hormone with application to t...
The accuracy of matrix population model projections for coniferous trees in the Sierra Nevada, California

Summary 1 We assess the use of simple, size-based matrix population models for projecting population trends for six coniferous tree species in the Sierra Nevada, California. We used demographic data from 16 673 trees in 15 permanent plots to create 17 separate time-invariant, density-independent population projection models, and determined differences between trends projected from initial surveys with a 5-year interval and observed data during two subsequent 5-year time steps. 2 We detected departures from the assumptions of the matrix modelling approach in terms of strong growth autocorrelations. We also found evidence of observation errors for measurements of tree growth and, to a more limited degree, recruitment. Loglinear analysis provided evidence of significant temporal variation in demographic rates for only two of the 17 populations. 3 Total population sizes were strongly predicted by model projections, although population dynamics were dominated by carryover from the previous 5-year time step (i.e. there were few cases of recruitment or death). Fractional changes to overall population sizes were less well predicted. Compared with a null model and a simple demographic model lacking size structure, matrix model projections were better able to predict total population sizes, although the differences were not statistically significant. Matrix model projections were also able to predict short-term rates of survival, growth and recruitment. Mortality frequencies were not well predicted. 4 Our results suggest that simple size-structured models can accurately project future short-term changes for some tree populations. However, not all populations were well predicted and these simple models would probably become more inaccurate over longer projection intervals. The predictive ability of these models would also be limited by disturbance or other events that destabilize demographic rates.
Ricci solitons on compact Kähler surfaces

We classify the Kaihler metrics on compact manifolds of complex dimension two that are solitons for the constant-volume Ricci flow, assuming that the curvature is slightly more positive than that of the single known example of a soliton in this dimension. INTRODUCTION The Ricci flow &g/8t = -2Ric(g) is an evolution equation for Riemannian metrics. In several cases [H1], [H2], [H3] the flow converges, up to re-scaling, to a metric of constant curvature. However, 4"soliton" solutions to the flow give examples where the Ricci flow does not uniformize the metric, but only changes it by diffeomorphisms. In this paper we are concerned with soliton solutions for the constant-volume Ricci flow 9gat = -2Ric(g) + 2rg on a compact manifold. (Here, r is the average of the scalar curvature.) Soliton solutions will be generated by initial data satisfying (1) ?Lxg = -2Ric(g) + 2-9 n for some vector field X. We will refer to these as compact solitons. In dimensions two [H3] and three [I2] the only compact solitons are constant curvature metrics, which are fixed under the constant volume flow. Nontrivial examples of compact solitons were constructed by Koiso [K], in the form of Kahler metrics of cohomogeneity one on certain JPl bundles on CPI. (For an elegant presentation of this construction, see [C].) These examples start in dimension four, with a metric on P(L E C), where L is the hyperplane bundle on CP1. We will discuss this particular example in more detail below. In this paper we show that a nontrivial soliton that is a Kaihler metric on a compact complex surface has curvature at least as negative as Koiso's example. (It is easy to see from applying the maximum principle to the evolution equation for the scalar curvature under the Ricci flow that any compact soliton must at least have strictly positive scalar curvature, or else it is an Einstein metric [I2].) Received by the editors July 26, 1995 and, in revised form, October 24, 1995. 1991 Mathematics Subject Classification. Primary 53C20, 53C21.
Assessing Broadband in America: OECD and ITIF Broadband Rankings

The United States continues to fall behind in broadband adoption, ranking 15th among 30 OECD nations according to the latest installment of the organization's semiannual survey of broadband subscribership. The number of U.S. broadband subscribers per 100 people grew to 19.6 in December 2006, up 0.4 percentage points from 19.2 in June 2006, a growth rate far below the 2.0 percentage point OECD average. Many of the leading European countries - including Denmark, Netherlands, Iceland, Switzerland, and Norway - continue to pull away from the pack with faster adoption rates. When the OECD first collected this data in 2001, the United States ranked 4th among the 30 nations surveyed. After several years of steady decline in the rankings, we now rank 15th (see Figure 1). While adoption rate is an important measure, it is not sufficient to accurately assess a nation's relative position in broadband technology. A more complete measure would also consider speed and price. Increasingly, in the digital economy it is the speed and capacity of the network that matters. Therefore, ITIF has expanded upon the OECD rankings, developing a model that measures broadband penetration, price and speed in OECD countries. The findings show that America, which ranks 12th overall, faces a multifaceted broadband challenge. There are several steps that policymakers should take to ensure faster progress toward ubiquitous high-speed broadband, including: - Congress should exempt broadband services from federal, state and local taxation and from requirements to pay into the Universal Service Fund. - All states should enact video franchise laws. - Congress should enact tax incentives for the deployment of new high-speed broadband networks. - The FCC should move to a two-tiered definition of high-speed Internet by developing a more robust 3 megabit per second (mbps) asymmetrical "broadband" standard. - The FCC should collect county-level subscriber data for both speed tiers. - If Congress fails to mandate changes to FCC local broadband data collection, states should work through non-governmental entities to collect and report local data. - The National Telecommunications and Information Administration (NTIA) should help facilitate the development of a bottom-up database of local broadband speeds and prices.
Ultralow Thermal Conductivity in Disordered, Layered WSe2 Crystals

The cross-plane thermal conductivity of thin films of WSe2 grown from alternating W and Se layers is as small as 0.05 watts per meter per degree kelvin at room temperature, 30 times smaller than the c-axis thermal conductivity of single-crystal WSe2 and a factor of 6 smaller than the predicted minimum thermal conductivity for this material. We attribute the ultralow thermal conductivity of these disordered, layered crystals to the localization of lattice vibrations induced by the random stacking of two-dimensional crystalline WSe2 sheets. Disordering of the layered structure by ion bombardment increases the thermal conductivity.
Swelling and mechanical behaviors of chemically cross-linked hydrogels of elastin-like polypeptides.

Genetically engineered elastin-like polypeptides consisting of Val-Pro-Gly-X-Gly repeats, where X was chosen to be Lys every 7 or 17 pentapeptides (otherwise X was Val), were synthesized and expressed in E. coli, purified, and chemically cross-linked using tris-succinimidyl aminotriacetate to produce hydrogels. Swelling experiments indicate hydrogel mass decreases by 80−90% gradually over an approximate 50 °C temperature range. Gels ranged in stiffness from 0.24 to 3.7 kPa at 7 °C and from 1.6 to 15 kPa at 37 °C depending on protein concentration, lysine content, and molecular weight. Changes in gel stiffness and loss angle with cross-linking formulation suggest a low-temperature gel structure that is nearly completely elastic, where force is transmitted almost exclusively through fully extended polypeptide chains and chemical cross-links, and a high-temperature gel structure, where ELP chains are contracted and force is transmitted through chemical cross-links as well as frictional contact between polype...
Nongyroresonant Pitch Angle Scattering

The spatial transport of charged particles, in a turbulence of slab Alfven waves and isotropic fast magnetosonic waves, is determined by the pitch angle scattering of these particles. For pitch angle cosines μ larger than the Alfven speed over the particle speed, this pitch angle scattering is provided by either gyroresonance with the Alfven waves or transit-time damping (TTD) with the fast-mode component of the spectrum. For smaller pitch angle cosines, however, there is no TTD, and if the particle rigidity is less than 1 GV, in the solar wind there is no gyroresonance possible either. A new nonresonant process is presented here that very efficiently scatters the particles through μ=0 and is due to waves that cannot be in gyroresonance with the particles. The contributions to the particles' mean free path, of this nonresonant scattering process as well as of the TTD and gyroresonant ones, are calculated. The application to low-energy cosmic rays in the solar wind leads to the following conclusions. Below 102-103 MV, the nonresonant process dominates the gyroresonant one at large pitch angles. Below 0.1-1 MV, the slowest scattering does not occur any longer at large pitch angles but at small ones, via TTD, with a relatively high and flat curve of mean free path versus rigidity. The resulting mean free path, between 10-2 and 105 MV, gives very reasonable fits for the observational data, which diversity could be explained by slight modifications of the turbulence parameters.
Structural analysis of poly(2-hydroxyethyl methacrylate) microparticles

Abstract Microparticles of crosslinked poly(2-hydroxyethyl methacrylate) were prepared by suspension polymerization. Their crosslinked structure was determined by equilibrium and dynamic swelling experiments in water. The number-average molecular weight between crosslinks, M c , was a function of the crosslinking ratio and the particle size, and it varied between 2030 and 6760. The water front velocity was constant throughout the swelling experiment and was a strong function of the crosslinking ratio. The results indicate that suspension polymerization of hydrophilic monomers may produce microparticles of progressively increasing degree of crosslinking from centre to surface.
ATP content of rat kidney cortex slices: Relation to α-aminoisobutyric acid uptake

ATP content of rat kidney cortex slices: Relation to α-aminoisobutyric acid uptake. ATP was measured in rat kidney cortex slices incubated in Krebs-Ringer bicarbonate buffer at 37° C and found to be 0.94 µmoles/g wet weight. The additions of various metabolic substrates were associated with both elevation and depression of this level. Octanoate produced the biggest decrease of ATP to 0.38 µmoles/g. Glucose, malate and succinate did not alter the level; acetate increased the level slightly. However, the greatest increase was produced by the addition of ATP to the medium (1.37 µ moles/g). Anaerobiosis and amytal, dinitrophenol, oligomycin and maleic acid additions were all associated with markedly lowered tissue ATP. The ATP content of tissue slices stored at 4° C for 24 to 72 hr was about half the value of fresh tissue slices. The relationship of ATP level to steady state α-aminoisobutyric acid uptake was examined. Normal amino acid uptake was seen over a wide range of ATP levels (0.38 to 1.37 µmoles/g). There was no direct correlation of ATP concentration with amino acid accumulation. The same decreased ATP level might be associated with normal uptake or depressed uptake depending on the means of lowering ATP. Depletion of ATP by anaerobiosis or metabolic inhibitors was, however, consistently associated with decreased amino acid uptake. Contenu en ATP des tranches de cortex renal de rat: Relation avec le prelevement d'acide α-aminoisobutyrique. L'ATP a ete mesuree dans des tranches de cortex renal de rat incubees dans du tampon Krebs-Ringer bicarbonate a 37° C, la valeur obtenue est de 0.94 µmoles/g de poids humide. Les additions de divers substrats metaboliques ont augmente ou diminue ces valeurs. L'octanoate a produit la baisse la plus importante de l'ATP a 0.38 µmoles/g. Le glucose, le malate et le succinate n'ont pas entraine de modification. L'acetate l'a augmente legerement et l'augmentation la plus importante a ete produite par l'addition d'ATP elle-meme au milieu (1.37 µmoles/g). L'anaerobiose et l'addition d'amytal, de dinitrophenol, d'oligomycine et d'acide maleique ont ete associes avec une reduction nette de l'ATP tissulaire. Le contenu en ATP de tranches de tissu conservees a 4° C pendant 24 a 72 heures etait d'environ la moitie de celui des tranches de tissu frais. La relation entre le contenu en ATP et le prelevement d'acide α-aminoisobutyrique a ete etudiee. Le prelevement normal de l'amino acide a ete observe dans un large eventail de valeurs de l'ATP (0.38 a 1.37 µmoles/g). II n'a pas ete constate de correlation directe entre la concentration d'ATP et l'accumulation d'aminoacide. La meme concentration basse d'ATP peut etre associee a un prelevement normal ou diminue en fonction du moyen utilise pour abaisser l'ATP. La depletion de l'ATP par l'anaerobiose ou les inhibiteurs metaboliques a ete, cependant, uniformement associee avec une diminution du prelevement deamino acide.
Quantifying the place of karst aquifers in the groundwater to surface water continuum: A time series analysis study of storm behavior in Pennsylvania water resources

Summary Though karst aquifers have commonly been identified, with respect to their behavior, as intermediate between ground and surface water, their putative location between these end members is generally descriptive rather than quantitative. Autocorrelation and spectral analysis of data from four karst springs, three wells, and eight stream gauges in Pennsylvania illustrate that specific karst water resources exhibit widely varying inertia with lag times that overlap those of groundwater and surface water. When analyzed in the frequency domain, the same data reveal distinctive patterns for each type of water resource. The four springs display characteristic lag times ranging from 5 to 25 days, compared to 1–10 days for streams and 11–46 days for wells. Physically, karst waters may behave as a mix of porous media, fracture, and open-channel flow, but in temporal terms the balance of this mix results in a range of system behaviors with characteristic periodicities evident in the karst aquifers. In the frequency domain, karst aquifers manifested slow flow paths as a gradual fall-off at lower frequency and quick flow paths as a flattening at high-frequency. Our comparison of water resources across different time periods revealed that the period considered can have strong effects on results. One spring displayed characteristic lag times of 12 and 25 days for two different time spans. To directly compare water resources over relatively short time scales, precipitation inputs must be similar and data sets must cover the same period; otherwise, substantial differences in lag times can be due to data collection and input differences rather than system characteristics. This limitation is less when the same data are analyzed in the frequency domain.
A Parent Evaluation of a Public Preschool Gifted Program.

The following article examines the definition of preschool gifted education in one state, briefly describes a publicly funded preschool gifted program that has operated for 10 years, and discusses parent responses to an evaluation instrument that examined six issues pertaining to a preschool gifted program. The responses were used as a basis for understanding a number of important issues associated with preschool gifted programming.
EDUCATIONAL ACHIEVEMENT PRIOR TO AND DURING HIGH SCHOOL1

A multivariate analysis of variance (MANOVA) was performed on the STEP, SCAT and socioeconomic (SES) scores of 2,952 “Growth Study” subjects at grades 7, 9 and 11. The Ss were grouped using grade 11 information according to 5 curricula, 2 sexes and 18 high schools so that the MANOVA of grade 7, 9 and 11 data was accomplished using these factors as design parameters. The findings indicate that at each grade the school, curriculum and sex factors were each associated with significant multivariate F ratios. As early as grade 7, meaningful differences in the performance and background of these Ss were apparent. For example, at grade 7 the performance of students who later enrolled in an academic curriculum was seen to be considerably higher than that of all nonacademic groups and was characterized primarily by a general achievement discriminant function. Among the nonacademic groups, the vocational curriculum students were distinguished from their other nonacademic peers in terms of performance on STEP Science and low SES, a trend that continued through grade 11. In general, it was found that the academic curricular group exhibited evenly distributed achievement across the areas covered by the STEP and SCAT tests from grades 7 to 11. The on-going achievement of the nonacademic groups appeared less uniform with higher achievement noted on STEP Science and Social Studies. The school factor was observed to distinguish significantly among the school groups at grade 7 in seven different ways. The first function was, however, a general achievement–SES dimension. The first discriminant function at grade 9 was interpreted as a STEP Listening–SES–STEP Science dimension where schools with high SES scores were ranked at the high positive end of the first discriminant score distribution. A more specific performance dimension characterized the first discriminant function at grade 9 and was given tentative interpretation as STEP Listening–SES–STEP Science. At grade 11 a positive SES, negative STEP Science dimension was the first discriminant function. The attributes which appeared to best describe the sample of students at each grade were, until grade 11, those on which higher SES groups did better. However, some lower SES groups made greater achievement gains over time than did higher SES groups. The differences that were found to remain among school groups at grade 11 are of practical educational importance, especially in the achievement areas covered by STEP Listening, Social Studies, Science and Math.
Fine structure of mononucleosomes derived by bright- and dark-field electron microscopy.

Abstract Images of intact and disrupted mononucleosomes, obtained by both bright-field (BF) and dark-field (DF) microscopy, were compared and analysed to determine the degree of continuity of morphological structures from the two visualization modes. DF images were about 10–13 % larger than BF images. Unless fixed with glutaraldehyde or stained with uranyl acetate, mononucleosomes may be partly unfolded. The 10.3 ± 1.1 nm diameter glutamate dehydrogenase hexamer, aggregates of histones H2 a , H2 b , H3 and H4 and naked DNA were used to estimate the contribution of protein and DNA to the images of mononucleosomes. The major contribution to the electron-dense regions of mononucleosomes viewed by the DF process is from histones and not DNA alone. Image analogs and autocorrelation methods were used to solve the three-dimensional organization of the nucleosome images in relation to the eight histones and the DNA. The structure of the mononucleosome which is most consistent with the data is that of a supercoiled nucleoprotein of 1.5 gyrs or greater with 8 roughly evenly spaced globular histone domains, each about 4.2 ± 0.7 nm in diameter, arranged as a pseudo-penta or hexamer as viewed along the central axis of symmetry. The structure is in essential agreement with models specified by Finch & Klug [12], and Trifonov [50].
Pete: an Extension Phenology Modeling System for Management of Multi-Species Pest Complex

A multi-species, phenology (or timing) modeling system described under the acronym of PETE (Predictive Extension Timing Estimator) has been developed for use by extension personnel to schedule integrated pest management (IPM) activities for a tree-fruit pest complex and selected vegetable pests in the state of Michigan. This computer-based system contains a library of pest models in a generalized format with appropriate software programs for constructing models with limited computer programming. It allows automatic operation, spot checking of pest status in the field, model testing, and model validation. When used with an earlier developed Pest Management Executive system (PMEX), it enables IPM extension personnel to monitor key events in the field and make appropriate recommendations to growers. The value of this program for summarizing phenological research and its practical value for implementing IPM methods are discussed.
Changing α with time: Implications for fifth-force-type experiments and quintessence

If the recent observations suggesting a time variation of the fine structure constant are correct, they imply the existence of an ultralight scalar particle. This particle inevitably couples to nucleons through the alpha dependence of their masses and thus mediates an isotope-dependent long-range force. The strength of the coupling is within a couple of orders of magnitude of the existing experimental bounds for such forces. The new force can be potentially measured in precision experimental tests of the equivalence principle. Because of a coincidence of the required time scales, the scalar field can at the same time play the role of a quintessence field.
Determination of surface-exposed, functional domains of gonococcal transferrin-binding protein A.

The gonococcal transferrin receptor is composed of two distinct proteins, TbpA and TbpB. TbpA is a member of the TonB-dependent family of integral outer membrane transporters, while TbpB is lipid modified and thought to be peripherally surface exposed. We previously proposed a hypothetical topology model for gonococcal TbpA that was based upon computer predictions and similarity with other TonB-dependent transporters for which crystal structures have been determined. In the present study, the hemagglutinin epitope was inserted into TbpA to probe the surface topology of this protein and secondarily to test the functional impacts of site-specific mutagenesis. Twelve epitope insertion mutants were constructed, five of which allowed us to confirm the surface exposure of loops 2, 3, 5, 7, and 10. In contrast to the predictions set forth by the hypothetical model, insertion into the plug region resulted in an epitope that was surface accessible, while epitope insertions into two putative loops (9 and 11) were not surface accessible. Insertions into putative loop 3 and β strand 9 abolished transferrin binding and utilization, and the plug insertion mutant exhibited decreased transferrin-binding affinity concomitant with an inability to utilize it. Insertion into putative β strand 16 generated a mutant that was able to bind transferrin normally but that was unable to mediate utilization. Mutants with insertions into putative loops 2, 9, and 11 maintained wild-type binding affinity but could utilize only transferrin in the presence of TbpB. This is the first demonstration of the ability of TbpB to compensate for a mutation in TbpA.
Correlates of Partner‐Specific Condom Use Intentions Among Incarcerated Women in Rhode Island

Unintended pregnancies and sexually transmitted diseases (STDs) are important and costly public health problems in the United States and are highly prevalent among incarcerated women. Nationally, 6–10% of incarcerated women are pregnant; 1,400 U.S. women gave birth while incarcerated in 1998.1 Pregnancies in this population usually are unplanned and high-risk, and they typically result in poor outcomes.2 Rates of STDs are substantially higher in the prison population than in the general population;3 for example, compared with the general female population, incarcerated women had a significantly higher prevalence of chlamydia (27% vs. 0.5%) and gonorrhea (8% vs. 0.1%) in 2001.4 In addition, many STDs increase the risk of HIV transmission at least threefold to fivefold.5 Most incarcerated women have had multiple sexual risk exposures. Hogben and colleagues found that incarcerated women had a relatively high lifetime number of sexual partners, and a large proportion had not used a condom at last sex; more than half reported a history of coerced sex.6 A history of physical or sexual abuse, in childhood or adulthood, is also common among incarcerated women,7 and such abuse may be linked to sexual and drug use behaviors that increase HIV risk.8 Additional sexual risk behaviors reported by incarcerated women are having exchanged sex for drugs or money, having engaged in sexual intercourse with injection drug users or HIV-positive partners, and having used alcohol or drugs before or during sex.9 Like many sexually active populations, incarcerated women typically have had sexual intercourse in relationships involving various levels of commitment, familiarity with partners and duration. Adults’ and adolescents’ use of condoms is more likely with casual partners than with main or steady partners.10 To date, few studies of incarcerated women’s sexual risk behaviors have considered these relationship context factors, and few have measured behavioral outcomes with reference to partner type to identify targets for risk reduction messages. A study that applied the theory of planned behavior to incarcerated women’s intentions to use condoms with main partners demonstrated that beliefs and attitudes about condoms, as well as social norms and perceived self-efficacy, all influence (directly or indirectly) behavioral intentions.11 However, that study focused on women with long prison sentences (three years or more) and did not assess behavioral intentions regarding nonprimary sexual partners. Further information on factors that influence incarcerated women’s decision-making regarding condom use with future primary and casual partners could help improve interventions to reduce these women’s risks of STD exposure and unplanned pregnancy after they are released. We report results of a study that we undertook to examine the following research question: What demographic, psychosocial, personal risk and behavioral variables are associated with incarcerated women’s intentions of future condom use with main and casual partners?
Functional polymers and sequential copolymers by phase transfer catalysis. XXII. Vinylidene fluoride–trifluoroethylene copolymers by surface modification of polyvinylidene fluoride

Synthese de ces copolymeres par deflorhydratation heterogene catalysee par transfert de phase de PVF 2 suivie de chloration ou bromation electrophile
SIMS depth-profiling studies: The effect of laser annealing on the distribution of ion-implanted boron in silicon☆

Abstract Secondary ion mass spectrometry (SIMS) was used to investigate the effect of pulsed laser annealing on the distribution of ion implanted boron in the surface region of silicon crystals. Above a laser pulse threshold energy of ∼1 J cm −2 , substantial redistribution of the implanted boron occurred which was both pulse energy density and pulse number dependent. A plausible explanation for the redistribution of B involves melting of the near surface region during laser irradiation and subsequent diffusion of the dopant in the liquid silicon.
Microstructural changes as a result of temperature gradients in the Al-Al 3 Ni eutectic

The microstructural changes accompanying exposure of the Al-Al3Ni eutectic to temperature gradients have been studied. It is observed that at high temperatures microstructural coarsening, as measured by transverse fiber density, is less during gradient as opposed to isothermal exposure. The converse holds to a much less degree at lower temperatures. The differences between the fiber densities during gradient and isothermal exposure are directly related to the temperature, the temperature gradient, and the time of exposure. Microchemical analysis was performed in an attempt to determine if there was redistribution of Al3Ni along the temperature gradient during such exposure. Experimental results were not entirely conclusive, but do suggest that the Al3Ni content is higher at the hot and cold ends in comparison to that in the center of the specimen. Numerical analysis was employed to test several theories relating to particle migration during elevated temperature exposure. It was found that a model of fiber migration controlled by diffusion along the fiber-matrix interfaces could account well for the observed values of fiber density and apparent redistribution of Al3Ni along the specimen length. Moreover, if reasonable values of the heat of transport of Ni in aluminum are assumed, the diffusion coefficient necessary to predict observed results agrees well with recently determined interfacial diffusion coefficients in a comparable (Al-CuAl2) system.