cssi/SciSciGPT-SciSciNet huggingface dataset:
Production of Non-Equilibrium Atomic Populations by Tunable Laser Excitation

This paper describes the use of tunable lasers to produce distributions of atomic or molecular populations far from thermal equilibrium. The technique makes it possible to study either atomic or molecular spectra characterizing such distributions or relaxation rates between levels. The principle is simply to produce a flux of photons sufficient to ensure that the rate of production of atoms in excited levels by absorption of photons is comparable to the rate of decay out of the excited levels. Such a flux equalizes the populations of the ground and excited levels coupled by the light, and the coupling of levels yields a ratio of populations that is independent of the thermal properties of the gas.
Hybrid pharmacokinetic models to describe anti-HIV nucleoside brain disposition following parent and prodrug administration in mice

Brain delivery of active anti-HIV compounds is important for successful treatment of the AIDS patient. As an initial step in predicting human brain drug concentrations, hybrid pharmacokinetic models were developed to characterize the disposition of anti-HIV nucleosides following parent and prodrug administrations in mice. Mouse data were obtained following intravenous administration of 3′-azido-2′,3′-dideoxyuridine (AZddU or AZDU), 3′-azido-3′-deoxythymidine (AZT), and their dihydropyridine prodrugs (AZddU-DHP and AZT-DHP). Exponential equations were fitted to the serum concentration–time data for each species, including the pyridinium ion moieties, and subsequently used in differential mass balance equations describing the brain dynamics of each compound. Model parameters for the mass balance equations were estimated by various techniques, including the utilization of in vitro data. In general, model-predicted brain concentrations agreed with the observed data. Similar data in larger animals will permit scale-up of the current model to predict human brain drug concentrations.
Deterministic and stochastic nutrient-phytoplankton- zooplankton models with periodic toxin producing phytoplankton

Deterministic and stochastic nutrient-phytoplankton-zooplankton models with toxin producing phytoplankton are studied.The input nutrient concentration and the toxin liberation rate play critical roles in the plankton dynamics.Periodic toxin liberation by phytoplankton can complicate plankton interactions.Harmful algal blooms can be diminished if the maximal toxin liberation rate is large. Deterministic and stochastic models of nutrient-phytoplankton-zooplankton interaction are proposed to investigate the impact of toxin producing phytoplankton upon persistence of the populations. The toxin liberation by phytoplankton is modeled periodically in the deterministic system. We derive two thresholds in terms of the parameters for which both plankton populations can persist if these thresholds are positive. We construct stochastic models with Ito differential equations to model variability in the environment. It is concluded that the input nutrient concentration along with the toxin liberation rate play critical roles in the dynamics of the planktonic interaction. In particular, toxin producing phytoplankton can terminate harmful algal blooms and the planktonic interaction is more stable if either the input nutrient concentration is smaller or if the toxin production rate is larger.
Sequential reconstruction segment-wise feature track and structure updating based on parallax paths

This paper presents a novel method for multi-view sequential scene reconstruction scenarios such as in aerial video, that exploits the constraints imposed by the path of a moving camera to allow for a new way of detecting and correcting inaccuracies in the feature tracking and structure computation processes. The main contribution of this paper is to show that for short, planar segments of a continuous camera trajectory, parallax movement corresponding to a viewed scene point should ideally form a scaled and translated version of this trajectory when projected onto a parallel plane. This creates two constraints, which differ from those of standard factorization, that allow for the detection and correction of inaccurate feature tracks and to improve scene structure. Results are shown for real and synthetic aerial video and turntable sequences, where the proposed method was shown to correct outlier tracks, detect and correct tracking drift, and allow for a novel improvement of scene structure, additionally resulting in an improved convergence for bundle adjustment optimization.
Maximum torque-per-ampere control of a saturated surface-mounted permanent magnet motor

The surface-mounted permanent magnet (SMPM) synchronous motor has high torque density and good dynamic response. Consequently, these machines have found applications in electric/hybrid vehicles, where size and volume are at a premium and dynamic response is important for vehicle performance. In these applications, high torque output from the motor is required for short time duration. The high stator current associated with this mode of operation can induce saturation in portions of the motor magnetic circuit and thus introduce saliency into a normally symmetric machine. This phenomenon can be exploited in order to maximize the torque output of the motor for the same stator current. The case of a 75 kW SMPM machine for automotive application is presented. By taking advantage of the saturation induced reluctance torque, up to 4% extra torque output is produced for the same maximum stator current. The improved performance is predicted using FEM calculations and is verified through experimental results.
The legacy of initial conditions in landscape evolution

Landscapes subject to constant forcing tend to evolve toward equilibrium states in which individual landforms have similar characteristics. Yet, even in landscapes at or near equilibrium, there can be significant variability among individual landforms. Furthermore, sites subject to similar processes and conditions can have different mean landform characteristics. This variability is often ascribed to on-going transient evolution, or to heterogeneity in processes, material properties, forcing, or boundary conditions. Three surprising outcomes of landform evolution models suggest, however, that such variability could arise in equilibrium landscapes without any heterogeneity in the physical processes shaping the topography. First, homogeneous systems subjected to constant forcing can generate a heterogeneous distribution of equilibrium landforms. Second, even simple non-linear systems can have multiple stable equilibrium states. Third, evolving landscapes can exhibit path dependence and hysteresis. We show how these three mechanisms can produce variability in landforms that arises from the characteristics of the initial topographic surface rather than from heterogeneity in geomorphic processes. Numerical experiments on the formation of low-order fluvial valleys and transportational cyclic steps in erodible streambeds illustrate why it is important to consider the influence of initial conditions when comparing models with natural topography, estimating the uncertainty of model predictions, and studying how landscapes respond to disturbances. Copyright © 2011 John Wiley & Sons, Ltd.
Coherent pairing of excitons in insulators and semiconductors

A microscopic theory is developed concerning the coherent pairing of Wannier-Mott type excitons in insulators and semiconductors. The coherent pairing of excitons occurs in the presence of a resonant electromagnetic field and the resulting energy gap is in competition with that induced by the electromagnetic field. Due to the electrical neutrality of the electron-hole pairs, the excitation spectrum is of the excitonic insulator type and the presence of the electromagnetic field results in the splitting of the energies of excitation. The expression for the coherent gap function depends on the exciton density, the effective exciton mass, the exciton-exciton interaction, and the effective energy band gap, which is equal to the difference between the transition frequency and the frequency of the field and the binding energy of the exciton. Under resonance conditions and at temperatures below some valueT c , the biexciton state can exist provided that the dielectric gap is less than that for the biexciton state. The ground-state energy resulting from the coherent pairing of excitons is calculated and is found to be lower in energy than the normal exciton state. This indicates the existence of a bound biexciton state as long as there is a net attractive exciton-exciton interaction.
Incorporating pelvic/vaginal reconstruction into radical pelvic surgery.

Abstract Objective The objective of this review is to discuss the more common surgical scenarios that often require pelvic/vaginal reconstruction with an emphasis on incorporating reconstructive options into the pelvic exenteration. Methods A review of the literature regarding pelvic/vaginal reconstruction in patients undergoing radical pelvic surgery was performed and supplemented with the authors' own experience. Results Reconstructive surgical procedures are often necessary with outcome goals that include any combination of enhanced wound healing, decrease in acute and chronic morbidity, and restoration of anatomic form and function. Many reconstruction techniques are available including, but not limited to, skin grafting, simple tissue transposition flaps, fasciocutaneous flaps, and myocutaneous flaps. It is extremely important that the gynecologic oncologist be proficient with more than one of the reconstructive options available to address the various pelvic/vaginal defects one may encounter. There is a wide range in the complexity of surgical situations requiring reconstruction. The pelvic exenteration in the previously radiated patient offers the highest level of challenge in terms of pre-operative planning, intra-operative decision-making and surgical skills. Vaginal reconstruction for sexual intercourse may be a priority for some patients, however pelvic/vaginal reconstruction plays a major role in facilitating wound healing, minimizing significant morbidity, and improving patient quality of life and functional outcomes. Conclusions The gynecologic oncologist is best suited to orchestrate this multifaceted surgical process. It is extremely important that the gynecologic oncologist be well versed in the reconstructive options available in order that it is optimally planned and effected at the primary surgical procedure.
Increased P diffusion as an explanation of increased p availability in flooded rice soils

Phosphorus supply factors (capacity, kinetic, intensity, and diffusivity) and plant growth were the approaches used to assess P supply of flooded rice soils. Increases in the capacity, intensity, and kinetic factors, as measured by E-value, solution P concentration, and soil P release rate to a distilled water ‘sink’ respectively, were unpronouced and infrequent upon water-saturation of ten soils. However, increases in the diffusitivity factor, as measured by 32P diffusion coefficients, were at least ten-fold as soil moisture increased. The greatest increases in P diffusion occurred as soil moisture increased beyond one-third bar.
Prolactin Receptor Gene Polymorphisms Are Associated with Gestational Diabetes

Aims: Human placental lactogen (hPL) acts via the prolactin receptor (PRLR) on maternal β-cells to mediate increases in β-cell mass and function during normal pregnancy. This interaction between hPL and PRLR is essential to maintain normal glucose homeostasis and to address the increased metabolic demands of pregnancy. Given the importance of the PRLR-hPL axis in pancreatic islet cell adaptation to pregnancy, we hypothesized that genetic variation in the PRLR gene could influence risk of development of gestational diabetes mellitus (GDM). DNA samples from 96 mothers affected by GDM and 96 unaffected cases were genotyped for 8 selected single nucleotide polymorphisms (SNPs) in PRLR. Results: Significant associations were identified in two SNPs analyzed. The minor alleles of PRLR SNPs rs10068521 and rs9292578 were more frequently observed in GDM cases than controls and were associated with a 2.36-fold increased risk for GDM in those carrying the minor allele. Conclusion: SNPs of the PRLR gene 5′ UTR and promoter region are associated with increased risk for GDM in a population of Chilean subjects.
Transformed School Counseling: The Impact of a Graduate Course on Trainees’ Perceived Readiness to Develop Comprehensive, Data-Driven Programs:

Trends indicate that the school counseling profession continues to undergo ignificant transformation. Training modules developed by the Education Trust and a case study approach were utilized to teach graduate students (n = 39) how to implement the ASCA National Model®. Pretests and posttests were administered to evaluate students' perceptions about the effectiveness of the course. Analysis indicates significant improvement in students' perceived competence (p < .003) across all dimensions except one. Results and implications for the profession are discussed.
The “Green” and “Gold” Roads to Open Access: The Case for Mixing and Matching

AbstractRecent discussions on Open Access (OA) have tended to treat OA journals and self-archiving as two distinct routes. Some supporters of self-archiving even suggest that it alone can bring about full Open Access to the world's scientific literature. In this paper, it is argued that each route actually corresponds to a phase in the movement toward Open Access; that the mere fact of self-archiving is not enough; that providing some branding ability to the repositories is needed. However, doing so will eventually bring about the creation of overlay (or database) journals. The two roads, therefore, will merge to create a mature OA landscape.
Early post-contrast T1 mapping yields maximal discriminatory capacity for detection of cardiac amyloid - influence of temporal T1 differences on MOLLI imaging

Methods Myocardial T1 mapping was performed in two cohorts (1) “amyloid +” subjects, defined by biopsy-proven systemic amyloid with associated remodeling suggestive of cardiac involvement (left ventricular [LV] hypertrophy and/or atrial dilation); (2) normative controls without risk factors for amyloid or cardiovascular disease. CMR (1.5T) included 2 components cine-CMR (SSFP) for cardiac structure/function, and T1 mapping for myocardial tissue characterization. T1 mapping was performed using a conventional modified look locker inversion recovery (MOLLI) sequence (flip angle = 30°; matrix 256 × 128; parallel imaging reduction factor =1.5; linear view ordering; 6 Kaiser-Bessel ramp preparation; 17 heart beat acquisition), with T1 calculated using an established formula (T1 = T1* (B/A-1), T1*, A, and B obtained via three-parameter exponential fit). To test time dependent differences in myocardial T1, MOLLI was acquired at sequential time points (3,5,10,14, 20 minutes) following intravenous administration of gadolinium (0.2 mmol/kg). Results 10 subjects (5 amyloid, 5 controls) were studied (44 ± 21 years, 40% male); all amyloid affected subjects had biopsyconfirmed disease (4 light chain type, 1 transthyretin). Amyloid subjects had higher LV mass (200 ± 34 vs. 101 ± 34 gm, p = 0.004), lower myocardial contraction fraction (32 ± 8 vs. 88 ± 27, p = 0.002), and larger left atrial area (26 ± 5 vs. 18 ± 5 cm2, p = 0.03) than controls, but similar LV end-diastolic volume (120 ± 24 vs. 133 ± 45 ml, p = 0.61), stroke volume (66 ± 10 vs. 86 ± 30 ml, p = 0.20), and LVEF (56 ± 10 vs. 65 ± 4%, p = 0.11). MOLLI was successfully acquired in all subjects at each time point: T1 differed significantly (all p ≤ 0.05) between amyloid and control groups at all times (Figure 1). However, magnitude of difference temporally decreased following gadolinium administration (Figure 2): T1 differences between patients and controls were maximal at 3 minutes post-contrast (135 ± 15 vs. 310 ± 61 msec, p = 0.004) with progressive decrements thereafter, as evidenced by 57% relative difference between groups at 3 minutes and only a 36% difference at 20 minutes following gadolinium infusion.
Inflammatory Cytokine Gene Expression in Blood During the Development of Oligofructose-Induced Laminitis in Horses

Abstract Systemic inflammation is a risk factor for laminitis in horses and precedes the onset of lameness in experimental models. We therefore hypothesized that whole-blood inflammatory cytokine expression would increase during the development of laminitis in a carbohydrate overload model. Blood samples were obtained from 14 horses undergoing laminitis induction with 10 g/kg oligofructose as part of another study. Samples were collected at 0, 8, 12, 16, 20, and 24 hours, and lameness evaluations were performed every 4 hours. Expression levels of interleukin-1β (IL-1β), IL-6, IL-8, IL-10, and tumor necrosis factor-α were measured in whole blood by using real-time PCR. IL-1β, IL-8, and IL-10 expression increased above baseline from 8 to 24 hours ( P P = .005). Expression of tumor necrosis factor-α did not change over time. All horses developed clinical laminitis between 12 and 24 hours. Increased mean IL-1β, IL-8, and IL-10 expression detected at 8 hours therefore preceded the onset of lameness. We conclude that peripheral leukocyte cytokine expression increases as systemic inflammation develops in an alimentary carbohydrate overload model of laminitis, and this precedes detection of lameness. Results support current recommendations to control the systemic inflammatory response in order to lower the risk of laminitis in horses.
Comparison of Flow Cytometry and Western Blotting To Measure Hsp70

The levels of constitutive and inducible forms of heat shock protein 70 (hsp73 and hsp72, respectively) through the cell cycle were measured in CHO cells by flow cytometry and Western blotting at various times after heating. Cells were labeled with antibody C92 (hsp72) or N27 (hsp73) and propidium iodide prior to analysis by flow cytometry. Cells were heated for 15 min at 45 degrees C, then analyzed from 3 to 36 h later. There was about a tenfold increase in hsp72 in early S phase cells beginning within 6 h after heating and these cells gradually cycled though S phase so by 36 h most of them had divided. When CHO cells were exposed to 10 microM sodium vanadate, an inhibitor of tyrosine phosphatase, for 24 h prior to heating, the induction of hsp72 in early S phase cells was almost completely inhibited. Heated cells did not express hsp73 in a cell-cycle-dependent manner. Hsp73 increased uniformly in all cells by 10 h after heating and sodium vanadate did not affect the expression. Quantitative comparisons of the relative levels of hsp72 and hsp73 measured by flow cytometry and Western blotting were in excellent agreement. Control and heated cells were labeled with Hoechst 33342 and sorted from G1, S, and G2/M phases and processed by Western blotting to verify the cell cycle dependent increase in hsp72 as measured by flow cytometry. Again there was excellent agreement between the Western blotting and flow cytometry results.
Characterization of a (BALB/c × C57BL/6)F1 T cell hybridoma with double specificity: recognition of antigen in context of I‐Ad and autoreactivity to I‐Ab

An antigen-specific, IL-2-producing, Lyt-1+2-, T cell hybridoma has been derived by the fusion of keyhole limpet hemocyanin (KLH)-primed (BALB/c x C57BL/6)F1 lymph node with BW5147 thymoma cells. The hybridoma FN13-21 recognizes KLH in association with I-Ad of BALB/c parental antigen-presenting cells, and also responds to I-Ab of the other parent C57BL/6 spleen cells in the absence of antigen. The KLH-specific response of FN13-21 is blocked by monoclonal anti-I-Ad antibody, while the response to C57BL/6 spleen cells is blocked by anti-I-Ab antibody. The specificity of the autoreactivity is to an antigen encoded for in the I-Ab region, as shown by the pattern of stimulation obtained with spleen cells from H-2-recombinant mice.
Response to the American Academy of Pediatrics, Committee on the Fetus and Newborn statement, "management of neonates with suspected or proven early-onset bacterial sepsis".

I am writing in response to the American Academy of Pediatrics Committee on the Fetus and Newborn (COFN) statement, “Management of Neonates With Suspected or Proven Early-Onset Bacterial Sepsis,” published in the May 2012 issue of Pediatrics .1 I am glad that Dr Polin and COFN have given emphasis to the current issues of concern in the evaluation of both preterm and term infants for early-onset sepsis (EOS). However, several of the recommendations continue traditional approaches to this problem, without acknowledging recent data on this subject that both raises concern about prolonged antibiotic administration and offers alternative approaches to risk assessment. My specific concerns are as follows. The statement continues to refer to the risk presented by maternal chorioamnionitis without offering a standard definition of this clinical diagnosis. From a practical standpoint, many obstetricians and neonatologists use this term almost interchangeably with intrapartum maternal fever. Our obstetrical colleagues often express reluctance to definitively make, or rule out, a diagnosis that they know will influence neonatal care. Both the COFN statement and the Centers for Disease Control and Prevention revised guidelines for the prevention of perinatal group …
Analysis of a few numerical integration methods for the Langevin equation

We study the position recurrence relation of several existing numerical integrators for the Langevin equation and use the modified equation approach to analyse their accuracy. We show that for the harmonic oscillator, the BBK integrator converges weakly with order 1 while the vGB82 and Langevin impulse (LI)‡ integrator converge weakly with order 2. We also study a restricted class of velocity definitions—those that lead to explicit starting procedures. We show that some recurrence relations exact for constant force, can achieve the exact virial relation by a proper definition of velocity, extending the result of Pastor et al. on the analysis of BBK integrators in 1988.
Spectropolarimetric properties of vegetation

Optical properties of vegetation materials are described. Spectral measurements of reflectance and Mueller matrices in the near infrared are given. The measurement method is discussed, and results are presented for a variety of plant material. Samples include both green leaves and bark. Measured results are compared to published results were possible.
Correlations between visual biomass scores and forage yield in space planted red clover (Trifolium pratense L.) breeding nurseries

Red clover (Trifolium pratense L.) forage yield remains a prime breeding target for improved variety development. In a world of decreasing forage legume breeding resources, rapidly and cheaply phenotyping plants for the highly quantitative trait of forage yield is vital. Many red clover selection programs are based on space planted nurseries. The objectives of this study were to determine: (1) the accuracy of visual forage yield scores in predicting actual forage yield; (2) the nature of the relationship between visual scores and actual measurements; and (3) The repeatability of visual scores between different evaluators. Twenty-seven halfsib families were transplanted at two locations in three replicates of six plant plots. Individual plant fresh weights and visual scores, by two evaluators, for forage yield were taken. On an individual plant basis visual forage yield scores showed an exponential relationship with actual fresh weights. Individual plant visual scores were very accurate with a pseudo-R2 of 0.79 observed for the exponential model. On an entry mean basis using a linear model, visual scores could explain 90% of the variation of actual fresh weights. Agreement among evaluators scoring the same plants was very high with coefficients of determination at 0.84 for individual plants and as high as 0.96 on an entry mean basis. This study suggests that visual scores of plants in space planted red clover breeding nurseries are basically as accurate as measuring actual yields and that plants can be consistently scored the same by different evaluators.
Cobalamin status in sickle cell disease

Background Some studies comparing serum cobalamin in individuals with and without sickle cell disease (SCD) have suggested a higher prevalence of cobalamin deficiency in SCD but others have not. Our aim was to prospectively compare cobalamin status in African-Americans with and without SCD.
Application Programming for MIDAS, a Multiprocessor System

All programs currently running on serial computers require some degree of modification when moved to parallel processors. This is true whether the architectural parallelism is manifested at the instruction level, such as in array processors or the CRAY, or achieved via multiple processors, as is the case in the MIDAS system. In either case the degree to which the program exploits the architecture can significantly affect the processing speed. Some guidelines for application programming for the MIDAS system are discussed. Important programming considerations include the separation of serial and parallel elements of a program (such as program initialization), data input mechanisms (including hardware preprocessing), and output mechanisms. Comparisons of code written for standard serial machines to the same code modified for MIDAS will be examined and performance results discussed.
A field theoretic formalism for the entanglements of a polymer network

Abstract Polymer networks can be made by cross linking chains, or by end linking, or both. Whereas cross linking is elegantly described by the methods of path integrals, end linking is better described by field theoretic methods. However, entanglements, at the level of the Gauss winding number integral, fit easily into path integrals, it is not obvious how to create a formalism for them in field theory. This is accomplished in this paper.
Neutron Resonance Spectroscopy. VII. Ti, Fe, and Ni

High-resolution neutron total cross-section measurements were performed on natural samples of titanium, iron, and nickel from 200 eV to a few MeV using the Nevis synchrocyclotron neutron velocity spectrometer with a 200-m flight path. The energy resolution was adequate only up to 200 keV to perform a detailed R-matrix multilevel analysis of the data. The resonance energies, isotopic and l-value assignment, neutron widths, etc., up to this energy have been determined. From these the mean level spacings 〈D〉 and the s-wave strength functions (S0) have been calculated. Information about the resonance parameters of the bound level in iron and nickel has been also obtained. Values of Γγ=8.2 eV for the Ti48 (17.8 keV) resonance, Γγ=0.64 for the bound level at -2 keV in Fe56, and Γγ=9.0 eV for the bound level at -28.5 keV in Ni58 have been determined by requiring an agreement with the measured thermal-neutron-capture cross section in these nuclei.
Gold-IgG complexes improve the detection and identification of viruses in leaf dip preparations☆

An immunoelectron microscopic method is described for rapid detection and identification of plant viruses in leaf-dip preparations by specific labelling with gold-IgG complexes. The process takes only 10 min and markedly improves the identification of viruses, particularly spherical ones including luteoviruses in leaf dips over simple antibody decoration.
A Case Study of Pediatric Pneumonia With Empyema

This case study provides a discussion of the diagnosis, management and comprehensive plan of care for empyema in children for the advanced practice registered nurse (APRN) working in primary care. The incidence of complicated pneumonias including those progressing to empyema is on the rise among pediatric patients. The ambiguous signs and symptoms of complicated pneumonias create a challenge for the provider when developing an accurate diagnosis and plan of care. Pediatric nurse practitioners must be cognizant of the increased incidence of complicated pneumonias and manage their patients accordingly. If left untreated, empyema may result in severe pulmonary complications.
Sperm chromatin-induced ectopic polar body extrusion in mouse eggs after ICSI and delayed egg activation

Meiotic chromosomes in an oocyte are not only a maternal genome carrier but also provide a positional signal to induce cortical polarization and define asymmetric meiotic division of the oocyte, resulting in polar body extrusion and haploidization of the maternal genome. The meiotic chromosomes play dual function in determination of meiosis: 1) organizing a bipolar spindle formation and 2) inducing cortical polarization and assembly of a distinct cortical cytoskeleton structure in the overlying cortex for polar body extrusion. At fertilization, a sperm brings exogenous paternal chromatin into the egg, which induces ectopic cortical polarization at the sperm entry site and leads to a cone formation, known as fertilization cone. Here we show that the sperm chromatin-induced fertilization cone formation is an abortive polar body extrusion due to lack of spindle induction by the sperm chromatin during fertilization. If experimentally manipulating the fertilization process to allow sperm chromatin to induce both cortical polarization and spindle formation, the fertilization cone can be converted into polar body extrusion. This suggests that sperm chromatin is also able to induce polar body extrusion, like its maternal counterpart. The usually observed cone formation instead of ectopic polar body extrusion induced by sperm chromatin during fertilization is due to special sperm chromatin compaction which restrains it from rapid spindle induction and therefore provides a protective mechanism to prevent a possible paternal genome loss during ectopic polar body extrusion.
Enhanced mobility in inverted AlxGa1-xAs/GaAs heterojunctions: binary on top of ternary

Single-period modulation doped inverted Al0.18Ga0.82As/GaAs heterostructures having the binary on top of the ternary were grown by molecular beam epitaxy. Despite the early reports of no mobility enhancement, considerable mobility enhancement, particularly at cryogenic temperatures, were obtained in the present structures. Mobilities of about 27 600 cm2/Vs with associated sheet carrier concentrations of about 6×1011 cm−2 were obtained at 10 K. The results represent the first enhanced mobilities obtained by molecular beam epitaxy and compare with 25 600 cm2/Vs deduced from Shubnikov de Haas measurements in LPE-grown structures at 4 K.
1H, 13C and 15N assignments and chemical shift-derived secondary structure of intestinal fatty acid-binding protein.

Sequence-specific 1H, 13C and 15N resonance assignments have been established for rat intestinal fatty acid-binding protein complexed with palmitate (15.4 kDa) at pH 7.2 and 37°C. The resonance assignment strategy involved the concerted use of seven 3D triple-resonance expriments (CC-TOCSY, HCCH-TOCSY, HNCO, HNCA, 15N-TOCSY-HMQC, HCACO and HCA(CO)N). A central feature of this strategy was the concurrent assignment of both backbone and side-chain aliphatic atoms, which was critical for overcoming ambiguities in the assignment process. The CC-TOCSY experiment provided the unambiguous links between the side-chain spin systems observed in HCCH-TOCSY and the backbone correlations observed in the other experiments. Assignments were established for 124 of the 131 residues, although 6 of the 124 had missing amide 1H resonances, presumably due to rapid exchange with solvent under these experimental conditions. The assignment database was used to determine the solution secondary structure of the complex, based on chemical shift indices for the 1Hα, 13Cα, 13Cβ and 13CO atoms. Overall, the secondary structure agreed well with that determined by X-ray crystallography [Sacchettini et al. (1989) J. Mol. Biol., 208, 327–339], although minor differences were observed at the edges of secondary structure elements.
Electrochemical Comparison and Deposition of Lithium and Potassium from Phosphonium- and Ammonium-TFSI Ionic Liquids

Two room-temperature ionic liquids, Bu 3 HexP + TFSI - [TFSI = bis(trifluoromethanesulfonyl)imide] and Bu 3 HexN + TFSI - , were synthesized and their electrochemical behavior was investigated using CV. The phosphonium-based ionic liquid (IL) showed improved stability and physical properties compared to the analogous ammonium-based IL. The phosphonium-based IL had higher conductivity (0.43 mS/cm) than the ammonium-based IL (0.28 mS/cm). The lower viscosity and higher stability of the phosphonium-based IL led to higher current density and stability for electrodeposited lithium metal. The addition of LiTFSI to both ILs led to a decrease in conductivity and increase in viscosity. An optimum deposition potential was found that was bounded by the electrochemical stability of each IL. The stability of lithium in the ILs increased at lower temperature due to slower reactivity with the IL. The electrodeposition and reoxidation of potassium was also demonstrated. It was found that a lithium-potassium alloy could be deposited at high current for long times without the occurrence of dendrites.
Protein phosphorylation in the brain

Protein phosphorylation represents an approach, sometimes the only approach available, to study the molecular basis for a wide variety of neurophysiological phenomena. The injection of protein kinases or protein kinase inhibitors into neurones has provided direct evidence that activation of protein kinases has an obligatory role in the mechanisms by which numerous extracellular signals produce specific physiological responses in neurones. A diversity of substrate proteins for the kinases have already been found. In several instances, the identity and functional role of these substrate proteins have been established.
Temperature dependent nanomechanics of Si–C–N nanocomposites with an account of particle clustering and grain boundaries

Experimentally obtained Silicon Carbide (SiC)-Silicon Nitride (Si 3 N 4 ) nanocomposites have SiC particles with nearly circular cross-section placed in Si 3 N 4 matrix either along grain boundaries (GBs) or in inter-granular locations. In the present investigation, 3-D molecular dynamics (MD) analyses of SiC-Si 3 N 4 nanocomposite deformation are performed at 300 K, 900 K, and 1500 K to understand the effect of SiC particle position with respect to the Si 3 N 4 GBs on the nanocomposite mechanical strength. A range of SiC-Si 3 N 4 nanocomposite phase morphologies having cylindrical SiC particles with diameter of 4 nm distributed in different manners in three different types of Si 3 N 4 phase matrices (single crystalline, bicrystalline, and nanocrystalline) are generated. Analyses reveal that the second phase particles act as significant stress raisers in the case of single crystalline Si 3 N 4 phase matrix. However, the particle's presence does not have a significant effect on the mechanical strength of bicrystalline or nanocrystalline Si 3 N 4 phase matrices. In order to understand the effect of grain boundary (GB) contamination on mechanical strength of the nanocomposites, structures having GBs with two different configurations: (1) sharp and (2) diffused; are analyzed. The strength of structures with diffused GBs decreased with increase in temperature with one exception for structures where due to the particle clustering the strength improved with increase in temperature. The findings indicate that the SiC-Si 3 N 4 interface plays an important role in strengthening the nanocomposite microstructure with increase in temperature through stronger Si-C-N bonding with increasing temperature. GBs on the other hand soften the structures by facilitating GB sliding based deformation mechanism. Overall, analyses confirm that the temperature dependent strengthening of the nanocomposite owing to SiC second phase particles is a strong function of particle placement along GBs, particle clustering, relative volume fractions of atoms in the interfaces and GBs, and GB thickness.
Oxygen diffusion in UO2−x

Abstract The tracer oxygen diffusivity in UO 2− x has been measured along the lower two-phase boundary. The diffusion couple consisted of two matched hypostoichiometric uranium dioxide wafers, one enriched with 18 O and the other normal, pressed together with a bond of liquid uranium in between. Oxygen-18 concentration profiles were determined by ion microprobe mass analysis, from which diffusion coefficients were obtained. Activation energy of anion vacancy migration was found to be (11.7±3.0) kcal / mole . A diffusion model for UO 2± x showed that both interstitials and vacancies contribute significantly to oxygen diffusion in stoichiometric UO 2 . The Frenkel defect energy and entropy of (85.6±9.2) kcal / mole and (18.2±7.2) e . u ., respectively, were deduced from the model. Using these values, the contribution of Frenkel disorder to the excess of UO 2 was evaluated. A simple two-band model for electronic excitation, with a band gap of 2.0 eV and effective electron mass of 7.6 m c , accounted for the remainder of the excess enthalpy.
ENHANCEMENT OF NUCLEATE POOL BOILING WITH POLYMERIC ADDITIVES

Abstract Heat transfer in the nucleate pool boiling of dilute aqueous polymer solutions was measured and compared with results for pure water. Solutes were hydroxyethyl cellulose (HEC) of three molecular weights, polyacrylamide (PA) of two molecular weights, and acrylamide; solute concentrations ranged from 62 ppm to 500 ppm. Liquids were boiled at atmospheric pressure on a horizontal steam-heated chrome-plated surface. Photographs showed distinct differences in bubble size and dynamics, between polymeric and nonpolymeric liquids. Heat flux in each polymer solution exceeded that for water, although the monomer acrylamide caused a reduction in heat transfer. Increases were as much as 250 per cent at ΔT ≈ 15°F and 100 per cent at ΔT ≈ 60°F. Results produced by variations of concentration and molecular weight appeared to be correlatable with the solution viscosity. The HEC is a surfactant but PA is not, so surface tension is believed to be only a minor variable. Explanations based on limited polymer solubility and solution viscoelasticity are proposed.
Doubly-Selective Multiuser Channel Estimation using Superimposed Training and Discrete Prolate Spheroidal Basis Expansion Models

Channel estimation for multiuser doubly-selective channels is considered using superimposed training. The time-varying channel is assumed to be described by a discrete prolate spheroidal basis expansion model (DPS-BEM). A user-specific periodic training sequence is arithmetically added (superimposed) at a low power to each user's information sequence at the transmitter before modulation and transmission. A two step approach is adopted where in the first step we estimate the channel using only the first-order statistics of the observations. Using the estimated channel from the first step, a Viterbi detector is used to estimate the information sequence. In the second step a deterministic maximum likelihood (DML) approach is used to iteratively estimate the multiuser channel and the information sequences sequentially.
A chemiluminescent probe specific for singlet oxygen

We have synthesized a methoxyvinylpyrene (MVP) in order to model the mechanism for the observed microsomal chemiluminescence of benzo[a]pyrene 7,8-dihydrodiol, the proximate carcinogenic metabolite of benzo[a]pyrene. This MVP analog has been found to be a highly efficient and specific chemiluminescent probe for picomole quantities of singlet oxygen and singlet oxygen equivalents, and it produces significant chemiluminescence when reacted with cytochrome P-450 enzymes.
Inactivation of human plasma α1-proteinase inhibitor by a metalloproteinase from serratia marcescens

Abstract The interaction of a Serratia marcescens metalloproteinase with human plasma α1-proteinase inhibitor has been investigated. The enzyme was not inactivated by this inhibitor but, instead, converted the native plasma protein into an inactive form of decreased molecular weight. Amino terminal sequence analysis indicated that the interaction of the inhibitor and enzyme was at the reactive site of the inhibitor, with peptide-bond cleavage resulting in the inactivation. This process may be important in necrotic processes occurring during bacterial infiltration of host tissues.
Nicotinic acetylcholine receptor-mediated calcium signaling in the nervous system

Based on the composition of the five subunits forming functional neuronal nicotinic acetylcholine receptors (nAChRs), they are grouped into either heteromeric (comprising both α and β subunits) or homomeric (comprising only α subunits) receptors. The nAChRs are known to be differentially permeable to calcium ions, with the α7 nAChR subtype having one of the highest permeabilities to calcium. Calcium influx through nAChRs, particularly through the α-bungarotoxin-sensitive α7-containing nAChRs, is a very efficient way to raise cytoplasmic calcium levels. The activation of nAChRs can mediate three types of cytoplasmic calcium signals: (1) direct calcium influx through the nAChRs, (2) indirect calcium influx through voltage-dependent calcium channels (VDCCs) which are activated by the nAChR-mediated depolarization, and (3) calcium-induced calcium release (CICR) (triggered by the first two sources) from the endoplasmic reticulum (ER) through the ryanodine receptors and inositol (1,4,5)-triphosphate receptors (IP3Rs). Downstream signaling events mediated by nAChR-mediated calcium responses can be grouped into instantaneous effects (such as neurotransmitter release, which can occur in milliseconds after nAChR activation), short-term effects (such as the recovery of nAChR desensitization through cellular signaling cascades), and long-term effects (such as neuroprotection via gene expression). In addition, nAChR activity can be regulated by cytoplasmic calcium levels, suggesting a complex reciprocal relationship. Further advances in imaging techniques, animal models, and more potent and subtype-selective ligands for neuronal nAChRs would help in understanding the neuronal nAChR-mediated calcium signaling, and lead to the development of improved therapeutic treatments.
RATES OF PRESENTATION, DISPLACED REHEARSAL, AND VERBAL DISCRIMINATION LEARNING

Summary.-Four experiments were conducted to test the notion that rehearsal in a verbal discrimination learning task is not confined to the feedbck interval, i.e., displaced rehearsal. Specifically, it was hypothesized that during early learning trials rehearsal would be restricted to the feedback interval. However, during later trials, once the subject was beyond the point of guessing the correct item, rehearsal could also occur during the anticipation interval. In all four experiments the opportunity for rehearsal was manipulated by presenting factorial combinations of either short or long anticipation and feedback intervals. Contrary to the hypothesis, no consistent differences were noted across trial blocks. However, the evidence did indicate thac a long anticipation interval combined with a short feedback interval facilitated learning relative to a short anticipation interval combined with a long feedback interval. A modified version of displaced rehearsal provides a reasonable explanation for this finding if it is assumed that correct recognition is not a prerequisite for displaced rehearsal.
Health Journalists and Three Levels of Public Information: Issue and Agenda Disparities?

This is a 2-phase study of the sources of information health journalists use and rely upon for writing health news stories. The 1st phase of the study includes both depth interviews and an online survey with 188 health journalists. Phase 2 of the study extends the findings from Phase 1, with particular attention paid to the roles of public health information officers at 3 government levels: local, state, and federal. Results from this study suggest that a monolithic, “1-size-fits-all” media relations model for public information officers is not adequate in the current health news environment. Findings explore differences in perceptions of the value of public information sources at 3 levels and suggest that some bureaucratic inefficiencies may interfere with more effective source/subsidy–provider relationships.
Laser photolysis of ND4. and trimethylamine formed by collisional neutralization of their cations in the gas phase

Abstract An experimental method is presented which utilizes 488 and 514.5 nm photons from an argon-ion laser to probe excited electronic states of neutral species formed by femtosecond collisional neutralization of cations and cation-radicals. Only a minor fraction of metastable ND 4 . from neutralization of ND 4 + is formed in ionizable electronic states. The dominant fraction is formed in the ground 2 A 1 (3s) state which is photodissociated to ND 3 and ND 2 . . Trimethylamine from neutralization of its cation radical is stable towards photoionixation and photolysis and is likely to be formed in its 1 A 1 ground electronic state.
Structure and Mutagenesis of Neural Cell Adhesion Molecule Domains EVIDENCE FOR FLEXIBILITY IN THE PLACEMENT OF POLYSIALIC ACID ATTACHMENT SITES

The addition of α2,8-polysialic acid to the N-glycans of the neural cell adhesion molecule, NCAM, is critical for brain development and plays roles in synaptic plasticity, learning and memory, neuronal regeneration, and the growth and invasiveness of cancer cells. Our previous work indicates that the polysialylation of two N-glycans located on the fifth immunoglobulin domain (Ig5) of NCAM requires the presence of specific sequences in the adjacent fibronectin type III repeat (FN1). To understand the relationship of these two domains, we have solved the crystal structure of the NCAM Ig5-FN1 tandem. Unexpectedly, the structure reveals that the sites of Ig5 polysialylation are on the opposite face from the FN1 residues previously found to be critical for N-glycan polysialylation, suggesting that the Ig5-FN1 domain relationship may be flexible and/or that there is flexibility in the placement of Ig5 glycosylation sites for polysialylation. To test the latter possibility, new Ig5 glycosylation sites were engineered and their polysialylation tested. We observed some flexibility in glycosylation site location for polysialylation and demonstrate that the lack of polysialylation of a glycan attached to Asn-423 may be in part related to a lack of terminal processing. The data also suggest that, although the polysialyltransferases do not require the Ig5 domain for NCAM recognition, their ability to engage with this domain is necessary for polysialylation to occur on Ig5 N-glycans.
Voicing and devoicing assimilation of French /s/ and /z/.

The present acoustic-phonetic study explores whether voicing and devoicing assimilations of French fricatives are equivalent in magnitude and whether they operate similarly (i.e., complete vs. gradient, obligatory vs. optional, regressive vs. progressive). It concurrently assesses the contribution of speakers’ articulation rate to the proportion of voicing (i.e., voicing ratios) in /s/ and /z/ embedded in fricative#stop sequences. Data analyses show that voicing and devoicing assimilation are similar in many regards: the absolute amounts of voicing change are equivalent in magnitude (0.77, 0.78) for the two processes: changes in voicing ratios are accompanied by changes in fricative and preceding vowel durations. These concomitant alterations result in the increased acoustic-phonetic similarity between the assimilated and the non-assimilated forms, suggesting that the two processes might be complete. In addition, the two processes operate regressively and across word-boundary. However, data show that the voicing assimilation of /s/ is not rate dependent, which suggest that it might be obligatory, while the devoicing assimilation of /z/ is rate dependent, which suggest that it might be optional.