cssi/SciSciGPT-SciSciNet huggingface dataset:
Fabrication and characterization of nanopores with insulated transverse nanoelectrodes for DNA sensing in salt solution.

We report on the fabrication, simulation, and characterization of insulated nanoelectrodes aligned with nanopores in low-capacitance silicon nitride membrane chips. We are exploring these devices for the transverse sensing of DNA molecules as they are electrophoretically driven through the nanopore in a linear fashion. While we are currently working with relatively large nanopores (6–12 nm in diameter) to demonstrate the transverse detection of DNA, our ultimate goal is to reduce the size sufficiently to resolve individual nucleotide bases, thus sequencing DNA as it passes through the pore. We present simulations and experiments that study the impact of insulating these electrodes, which is important to localize the sensing region. We test whether the presence of nanoelectrodes or insulation affects the stability of the ionic current flowing through the nanopore, or the characteristics of DNA translocation. Finally, we summarize the common device failures and challenges encountered during fabrication and experiments, explore the causes of these failures, and make suggestions on how to overcome them in the future.
Patterns of Polydrug Use Among Ketamine Injectors in New York City

Polydrug use is an important public health issue since it has been linked to significant adverse health outcomes. Recently, club drugs, including ketamine and other drugs used in dance/rave scenes, have been identified as key substances in new types of polydrug using patterns. While seemingly a self-explanatory concept, “polydrug” use constitutes multiple drug using practices that may impact upon health risks. Ketamine, a club drug commonly administered intranasally among youth for its disassociative properties, has emerged as a drug increasingly prevalent among a new hidden population of injection drug users (IDUs). Using an ethno-epidemiological methodology, we interviewed 40 young (< 25 years old) ketamine injectors in New York during 2000–2002 to describe the potential health risks associated with ketamine and polydrug use. Findings indicate that ketamine was typically injected or sniffed in the context of a polydrug using event. Marijuana, alcohol, PCP, and speed were among the most commonly used dru...
The fracture behavior of an Al–Mg–Si alloy during cyclic fatigue

Abstract In this paper, is presented and discussed the cyclic fracture behavior of the Al–Mg–Si alloy 6063 that is a candidate used in luminaire light poles. The light poles were subject to fatigue deformation. Test sections were taken from the failed region of the light pole and carefully examined in a scanning electron microscope with the objective of rationalizing the macroscopic fracture mode and intrinsic micromechanisms governing fracture under cyclic loading. The fatigue fracture surface of the alloy revealed distinct regions of early microscopic crack growth, stable crack growth and unstable crack growth and overload. An array of fine striations was found covering the regions of early and stable crack growth. Both macroscopic and fine microscopic cracks were found in the region of unstable crack growth. Very few microscopic voids and shallow dimples were evident on the fatigue fracture surface indicative of the limited ductility of the alloy under cyclic loading conditions.
Measuring Faculty Reflection on Medical Grand Rounds at Mayo Clinic: Associations With Teaching Experience, Clinical Exposure, and Presenter Effectiveness

Abstract Objectives To develop and validate a new instrument for measuring participant reflection on continuing medical education (CME) and determine associations between the reflection instrument scores and CME presenter, participant, and presentation characteristics. Participants and Methods This was a prospective validation study of presenters and faculty at the weekly medical grand rounds at Mayo Clinic in Rochester, Minnesota, from January 1, 2011, through June 30, 2011. Eight items (5-point Likert scales) were developed on the basis of 4 reflection levels: habitual action, understanding, reflection, and critical reflection. Factor analysis was performed to account for clustered data. Interrater and internal consistency reliabilities were calculated. Associations between reflection scores and characteristics of presenters, participants, and presentations were determined. Results Participants completed a total of 1134 reflection forms. Factor analysis revealed a 2-dimensional model (eigenvalue; Cronbach α): minimal reflection (1.19; 0.77) and high reflection (2.51; 0.81). Item mean (SD) scores ranged from 2.97 (1.17) to 4.01 (0.83) on a 5-point scale. Interrater reliability (intraclass correlation coefficient) for individual items ranged from 0.58 (95% CI, 0.31-0.78) to 0.88 (95% CI, 0.80-0.94). Reflection scores were associated with presenters' speaking effectiveness ( P P =.02), participants' prior clinical experiences ( P P P Conclusion We report the first validated measure of reflection on CME at medical grand rounds. Reflection scores were associated with presenters' effectiveness and prior teaching experience, participants' clinical exposures, and presentations that were interactive and clinically relevant. Future research should determine whether reflection on CME leads to better patient outcomes.
Laser Scattering Phenomenology - Background Signature Characterization And Prediction

ABSTRACTLaser Scattering Phenomenology - Background SignatureCharacterization and PredictionDavid L. MeekerUS Army Engineer Waterways Experiment Station (WES)P.O. Box 631, Vicksburg, MS 39180 -0631 An important part of WES's remote sensing program is the develop-ment of electromagnetic energy signature maps that vary as environ-mental conditions change in an area. Such maps are useful forassessing electromagnetic sensor technology since the effectiveness ofelectro- optical sensors is dependent on weather and terrain backgroundconditions. A model has been developed to predict the laser signa-tures of various types of terrain backgrounds under selected weatherconditions. Experiments have been conducted to calibrate the laserscattering model. This model has been integrated with terrain eleva-tion data and land use maps to produce color displays that indicateterrain areas exhibiting high or low laser scattering. Displaysprovide researchers with a tool for developing the background signa-ture terrain maps needed to evaluate tactical sensor.technology anddelineate specific features of interest.
Mechanistic Studies on the Extraction of Copper by 5,8-Diethyl-7-hydroxy-dodecane-6-one Oxime (LIX 63)

Abstract A detailed study of equilibrium and kinetic aspects of the extraction of Cu(II) from solutions containing nitriloacetic acid (NTA) or iminodiacetic acid (IDA) (H n Y) into chloroform solutions of LIX 63 (HL) (found to be monomeric) established the following equilibrium: with-K'ex values of 10−7.23 and 10−5.26 at 25°C and 0.1 M Na2SO4 when H3Y or H2Y represented NTA and IDA, respectively. From these data the extraction constant applicable in the absence of masking agents was calculated as K ex = 10−3.82·0.10. The experimental expression for the rate of extraction of Cu(II) by LIX 63 was found to be -d[Cu]/dt = k'[Cu2+][HL]/[HY2−]x. The fractional order dependence on NTA (x = 0.51) or IDA (x = 0.34) is consistent with a mechanism in which concurrent reaction paths for CuOH+ and CuY− with neutral LIX 63 molecules in the aqueous phase to form CuL+ represent the rate-limiting steps.
Electron spin resonance investigations on ion beam irradiated single-wall carbon nanotubes

Abstract ESR investigations on single-wall carbon nanotubes irradiated with accelerated protons, helium ions, and neon ions are reported. All spectra were accurately simulated assuming that the resonance line is a convolution of up to 4 lines originating from catalyst residues, amorphous carbon, and electrons delocalized over the conducting domains of nanotubes. The faint line observed in irradiated nanotubes at g > 2.25 was assigned to magnetic impurities. However, there are no sufficient data to confirm that this line is connected to radiation-induced magnetism in carbon nanotubes. The generation of paramagnetic defects due to the bombardment of single-wall carbon nanotubes by accelerated ions is reported. These data correlate with previous Raman and thermal investigations on the same single-wall carbon nanotubes and reveals their sensitivity to ionizing radiation. The temperature dependence of ESR spectra in the range 25–250 K was used to identify the components of the ESR spectra.
The Applicability of the Immersion Approach to College Foreign Language Instruction

The immersion approach to second language teaching differs from conventional skills-based instruction in that in immersion the target language is used primarily as a vehicle for teaching other subjects in the school curriculum. Extensive evaluation has shown that immersion students, when compared to students in traditional language courses, develop higher levels of language skills and more positive attitudes towards language study. While the results of the Canadian immersion program have already led to the creation of similar programs in over a dozen school districts in the United States, its impact on the design of college foreign language instruction has yet to be felt. This paper argues that the research on immersion and subject-matter teaching indicates this approach to be both a feasible and desirable alternative to traditional skills-based instruction for college foreign language programs.
Comparison of Pulsed and Continuous-Wave Deposition of Thin Films from Saturated Fluorocarbon/H2 Inductively Coupled rf Plasmas

Thin films are prepared by plasma polymerization using inductively coupled continuous-wave (CW) and variable duty cycle pulsed rf plasmas. The effects of hydrogen addition (0−97.5%) on thin films deposited from CW saturated fluorocarbon (CF_4 and C_2F_6) plasmas are examined. Variable duty cycle, pulsed C_2F_6 rf plasmas are employed for comparison to the CW results. Film properties are determined using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). Deposition rates and contact angles are also measured for all films. Analysis using these techniques indicates a strong dependence of the bulk and surface structure on the hydrogen content of the feed in the CW systems. Significantly different film chemistry and deposition rates are observed in the pulsed systems. For the pulsed systems, film composition is dependent on duty cycle and relative pulse on and off times. Using an optimum duty cycle of 3% results in a less cross-linked fluorocarbon polymer, with primarily CF_2 species in the bulk film and CF_3 surface termination.
A Replication of “Dividend Taxes and Implied Cost of Equity Capital” (Journal of Accounting Research 2005)

Three major measures of implied cost of equity are sensitive to a summary measure on macroeconomic conditions (the Chicago Fed National Activity Index, or CF3) while changes in the tax rates on inv...
Mouse translation elongation factor eEF1A‐2 interacts with Prdx‐I to protect cells against apoptotic death induced by oxidative stress

eEF1A-1 and eEF1A-2 are two isoforms of translation elongation factor eEF1A. In adult mammalian tissues, isoform eEF1A-1 is present in all tissues except neurons, cardiomyocytes, and myotubes, where its isoform, eEF1A-2, is the only form expressed. Both forms of eEF1A have been characterized to function in the protein elongation step of translation, and eEF1A-1 is shown to possess additional non-canonical roles in actin binding/bundling, microtubule bundling/severing, and cellular transformation processes. To study whether eEF1A-2 has similar non-canonical functions, we carried out a yeast two-hybrid screening using a full sequence of mouse eEF1A-2 as bait. A total of 78 hits, representing 23 proteins, were identified and validated to be true positives. We have focused on the protein with the highest frequency of hits, peroxiredoxin I (Prdx-I), for in-depth study of its functional implication for eEF1A-2. Here we show that Prdx-I coimmunoprecipitates with eEF1A-2 from extracts of both cultured cells and mouse tissues expressing this protein, but it does not do so with its isoform, eEF1A-1, even though the latter is abundantly present. We also report that an eEF1A-2 and Prdx-I double transfectant increases resistance to peroxide-induced cell death as high as 1 mM peroxide treatment, significantly higher than do single transfectants with either gene alone; this protection is correlated with reduced activation of caspases 3 and 8, and with increased expression of pro-survival factor Akt. Thus, our results suggest that eEF1A-2 interacts with Prdx-I to functionally provide cells with extraordinary resistance to oxidative stress-induced cell death. J. Cell. Biochem. 100: 267–278, 2007. © 2006 Wiley-Liss, Inc.
Broad bandwidth, efficient, metamaterial-inspired, electrically small antennas augmented with internal non-Foster elements

Broad bandwidth metamaterial-inspired electric and magnetic antennas have been designed and characterized numerically. By augmenting their narrow bandwidth counterparts with internal non-Foster elements, active metamaterial unit cells are introduced as near-field resonant parasitic (NFRP) elements. Nearly complete matching of the entire system to a 50 Ω source without any matching network and high radiation efficiencies over their FBW 10dB bandwidths that are more than 75 times their original values have been achieved.
Effect of Sugars on Headgroup Mobility in Freeze-Dried Dipalmitoylphosphatidylcholine Bilayers: Solid-State 31P NMR and FTIR Studies

The effect of the carbohydrates trehalose, glucose, and hydroxyethyl starch (HES) on the motional properties of the phosphate headgroup of freeze-dried dipalmitoylphosphatidylcholine (DPPC) liposomes was studied by means of 31P NMR, Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). The results show that trehalose, which is a strong glass former (Tg = 115 degreesC), elevates the onset of the lipid headgroup rotations and preserves some rotational mobility of the phosphate headgroups after cooling from the liquid-crystalline state. Glucose (Tg = 30 degreesC), a very effective depressant of the phase transition temperature of freeze-dried DPPC, markedly elevates the initiation of the temperature of headgroup rotations. On the other hand, the monosaccharide does not preserve the headgroup disordering when cooled from the liquid-crystalline state. These effects are consistent with formation of hydrogen bonds between the OH groups of the sugar and the polar headgroups of DPPC. They show, however, that hydrogen bonding is not sufficient for preservation of the dynamic properties of freeze-dried DPPC. HES, although a very good glass former (Tg > 110 degreesC), does not depress the phase transition temperature and affects only slightly the rotational properties of freeze-dried DPPC. This lack of effect of HES is associated with the absence of direct interactions with the lipid phosphates, as evidenced by the FTIR results. These data show that vitrification of the additive is not sufficient to affect the dynamic properties of dried DPPC.
On the Behavior of Pt(111)−Bi in Acid and Alkaline Electrolytes

We studied the base voltammetry of Pt(111) modified by irreversibly adsorbed Bi in both 0.1 M HClO4 and 0.1 M NaOH. By comparing the cyclic voltammograms in both electrolytes for the same Biir cove...
Three-level atoms inside a degenerate optical parametric oscillator: Steady-state behaviors

We study a composite system consisting of N three-level \ensuremath{\Lambda}-type atoms and a degenerate optical parametric oscillator (DOPO). The standard DOPO threshold is modified by the presence of the three-level atoms. Bistability (in the intracavity field intensity versus pumping intensity for the DOPO) appears for certain atomic detunings and coupling field strengths between the intracavity field and one of the atomic transitions. The effects of the coupling field (for the auxiliary transition in the three-level atomic system) are discussed. The susceptibility of the three-level atoms is calculated for the lower and upper branches of the bistable curve. Both analytical (for certain special cases) and numerical (for more general cases) results are presented.
Plasma growth hormone, insulin, glucocorticoids and thyroid hormones in large, medium and small breeds of steers with and without an estradiol implant

Abstract Growth hormone secretory patterns and plasma concentrations of insulin, adrenal corticosteroids, thyroxine and triiodothyronine were measured in three types of steers with and without estradiol implants. The three types of cattle were large (Simmental), medium (Limousin) and small (Angus) frame size with medium, low and high propensity to deposit fat. Simmental steers had higher (P
Validity Issues in Assessing English Language Learners' Language Proficiency

The No Child Left Behind Act has made a great impact on states' policies in assessing English language learner (ELL) students. The legislation requires states to develop or adopt sound assessments to validly measure the ELL students' English language proficiency (ELP). Although states have moved rapidly to meet these requirements, they face challenges to validate their current assessment and accountability systems for ELL students, partly because of the lack of resources. Considering the significant role of assessments in guiding decisions about organizations and individuals, it is of paramount importance to establish a valid assessment system. With the purpose of providing an overview to critical issues in validating the use of ELP assessments, this article reviews validity framework, key issues to consider in validating the ELP assessment system, and the current status of practice relative to validating ELP assessment.
Indirect photodegradation of dissolved free amino acids: the contribution of singlet oxygen and the differential reactivity of DOM from various sources.

The role of photochemically generated singlet oxygen (1O2) in the DOM-sensitized degradation of eighteen dissolved free amino acids was investigated. The fraction of total sensitized degradation due to reaction with 1O2 was determined through a kinetic analysis based on a measured reaction rate constant for each amino acid coupled with measured 1O2 concentrations and was confirmed through quenching experiments. Only four of the eighteen free amino acid residues examined were found to be photolabile under environmentally relevant conditions: histidine, methionine, tyrosine, and tryptophan. The fraction of Suwannee River Humic Acid (SRHA)-sensitized degradation due to reaction with 1O2 ranged from an upper value of 110 ± 10% for histidine to 8 ± 1% for tryptophan, with 26 ± 3% contribution for methionine and 33 ± 4% for tyrosine. In addition to degradation through reaction with 1O2, other reactive intermediates involved in the SRHA-photosensitized degradation of these amino acids were identified. Methionine...
Pulsed electron paramagnetic resonance spectroscopy powered by a free-electron laser

Electron paramagnetic resonance (EPR) spectroscopy interrogates unpaired electron spins in solids and liquids to reveal local structure and dynamics; for example, EPR has elucidated parts of the structure of protein complexes that other techniques in structural biology have not been able to reveal. EPR can also probe the interplay of light and electricity in organic solar cells and light-emitting diodes, and the origin of decoherence in condensed matter, which is of fundamental importance to the development of quantum information processors. Like nuclear magnetic resonance, EPR spectroscopy becomes more powerful at high magnetic fields and frequencies, and with excitation by coherent pulses rather than continuous waves. However, the difficulty of generating sequences of powerful pulses at frequencies above 100 gigahertz has, until now, confined high-power pulsed EPR to magnetic fields of 3.5 teslas and below. Here we demonstrate that one-kilowatt pulses from a free-electron laser can power a pulsed EPR spectrometer at 240 gigahertz (8.5 teslas), providing transformative enhancements over the alternative, a state-of-the-art ∼30-milliwatt solid-state source. Our spectrometer can rotate spin-1/2 electrons through π/2 in only 6 nanoseconds (compared to 300 nanoseconds with the solid-state source). Fourier-transform EPR on nitrogen impurities in diamond demonstrates excitation and detection of EPR lines separated by about 200 megahertz. We measured decoherence times as short as 63 nanoseconds, in a frozen solution of nitroxide free-radicals at temperatures as high as 190 kelvin. Both free-electron lasers and the quasi-optical technology developed for the spectrometer are scalable to frequencies well in excess of one terahertz, opening the way to high-power pulsed EPR spectroscopy up to the highest static magnetic fields currently available.
Conceptual Design For Active Structural Control Of A Large Optical System

A design for the active structural control of a two-element laser beam expander is described. The lengths of selected struts of a trussed, quadrapod graphite/epoxy structure are monitored and controlled by sensor/actuators using a modal control technique with rate-damping enhancement. The details of structural design, optical arrangement, strut sensors and actuators, and control algorithms are discussed.
Possible processes in the immune surveillance of the intracellular space

Abstract Many potentially antigenic substances in stable cells lie intracellularly and are generally thought to lie outside the purview of immunologic surveillance. Arguments countering this notion are presented herein. It is further suggested that intracellular spaces are monitored by lymphocytes migrating through other cells in the process of “emperipolesis”.
Untethering the TIR1 auxin receptor from the SCF complex increases its stability and inhibits auxin response

Plant genomes encode large numbers of F-box proteins (FBPs), the substrate recognition subunit of SKP1-CULLIN-F-box (SCF) ubiquitin ligases. There are ~700 FBPs in Arabidopsis, most of which are uncharacterized. TIR1 is among the best-studied plant FBPs and functions as a receptor for the plant hormone auxin. Here we use a yeast two-hybrid system to identify novel TIR1 mutants with altered properties. The analysis of these mutants reveals that TIR1 associates with the CULLIN1 (CUL1) subunit of the SCF through the N-terminal H1 helix of the F-box domain. Mutations that untether TIR1 from CUL1 stabilize the FBP and cause auxin resistance and associated growth defects, probably by protecting TIR1 substrates from degradation. Based on these results we propose that TIR1 is subject to autocatalytic degradation when assembled into an SCF. Further, our results suggest a general method for determining the physiological function of uncharacterized FBPs. Finally, we show that a key amino acid variation in the F-box domain of auxin signalling F-box (AFB1), a closely related FBP, reduces its ability to form an SCF, resulting in an increase in AFB1 levels.
Smoking Policy in Peidatric Wards and Hospitals

The AAP has recommended that pediatricians take the lead in banning cigarette smoking in all pediatric health care facilities. This study investigated the use of “nonsmoking” policies and their planned revisions, problems in enforcement and challenges to restrictive or lenient policies. Mail surveys were sent to all 320 hospitals affiliated with pediatric training programs as the institutions most likely to attempt to comply with the AAP recommendations. Based on data from the first 1/3 of the sample, the hospitals had a range of 12-265 pediatric beds in children's hospitals 26% or defined areas of larger hospitals 71%. All but 3 had formal smoking policies, in place for a median of 6 mos-2 yrs. 72% had revised or were planning revision within the next year. 57% of policies were governed by city, state, university or other regulating bodies. Smoking was entirely banned from all public and private areas in 8%. All programs restricted smoking to designated areas only. Most policies applied to all patients, visitors and employees and to all in- and outpatient facilities. The most common designated areas for smoking were: cafeteria 66%, private offices 62%, outside courtyards 48%, staff lounges 41%, smoking waiting rooms 40%; 78% allowed patient smoking. Policies were made public by signs 93% or brochures 55%. Penalties were usually “leave nonsmoking area” 79% or disciplinary measures for employees 47%. Responsibility of enforcement lay with all employees 88%, security 41% or supervisors 41%. Only 19% reported strict enforcement with stringent penalties. 48% of policies had been challenged by employees, patients or physicians; all but one were dealt with by the hospital administration. Although nearly all policies have been recently or are being revised, pediatric hospitals and wards remain sadly remiss in controlling smoking.
Detection of the direction and speed of motion of forces on the surface of a compliant tactile sensor

A compliant tactile sensor (CTS) has been developed with two orthogonal layers of multi-walled carbon nanotubes (MWNTs) and polymer strips. This has enabled the detection of sliding motion along the surface of the sensor. This information is used to detect the motions of forces applied on the surface of the CTS. The speed of sliding motion in each direction can be updated with a resolution of 3mm in both of two perpendicular directions.
Oscillations of η3-allyl groups in pseudooctahedral molybdenum and tungsten complexes

Abstract The allyl groups in cationic pseudooctahedral complexes of molybdenum and tungsten complexes containing bidentate phosphine ligands undergo oscillations between two potential minima. The fluxional behavior in these [(η 3 -C 3 H 5 )M(CO) 3 (LL)] + complexes, where LL = diphos, dppe or dppm, differs from that in neutral analogs, for which pseudorotation of the ligands is observed.
Intravenous antiplatelet efficacy and safety of the platelet GPIIb/IIIa antagonist, DMP 728 in anesthetized dogs

Abstract DMP 728, cyclo (D-2-aminobutyrate - N-Methyl -L-Arginyl - Glycyl -L-Aspartyl-3-amino-methyl -benzoic acid) methanesulfonate salt, is a novel antiplatelet agent with high affinity and specificity for human and canine platelet GPIIb/IIIa (α2/β3) receptors. DMP 728 demonstrated a potent antiplatelet efficacy in inhibiting ADP-induced platelet aggregation in either human or canine PRP with an IC50 of 0.046 and 0.015 μM, respectively. The IC50 of DMP 728 in inhibiting human platelet aggregation in PRP ranged from 0.02 - 0.05 μM regardless of the agonist used or even their combinations. Additionally, DMP 728 displayed a much greater affinity in inhibiting 125I-fibrinogen binding to stimulated human platelets as compared to the linear peptide RGDS or fibrinogen. The present study was undertaken to examine the IV antiplatelet efficacy and safety of DMP 728 in anesthetized dogs. In anesthetized mongrel dogs, DMP 728 (0.001-1.0 mg/kg, IV bolus) produced a dose-dependent inhibition of ex vivo platelet aggregation induced by ADP. The onset of inhibition was immediate, and the duration of antiplatelet effects was dose-dependent. A maximal inhibition of platelet aggregation and a reversible prolongation of bleeding time at 0.01 mg/kg were shown. Additionally, the antiplatelet efficacy/safety of DMP 728 was examined after IV administration at different infusion rates ranging from 0.008 to 0.833 μg/kg/min for 2 hours. A minimal antiplatelet effect was observed at the 0.008 μg/kg/min for 2 hours, while a maximal inhibition of platelet aggregation along with a reversible prolongation of bleeding time was achieved at 45–60 min post-infusion of 0.08 μg/kg/min × 2 hours. Prolongation of bleeding time was significantly reduced upon the cessation of the infusion while maximal inhibition of platelet aggregation was maintained longer. At all of the above regimens, DMP 728 did not result in any significant effects on platelet counts. Furthermore, DMP 728 did not elicit any other platelet unrelated adverse effects over wide range of doses. These data suggest that DMP 728, a low molecular weight platelet GPIIb/IIIa receptor antagonist, is a potent and systemically active antiplatelet agent with reversible effects on bleeding time.
Highly conserved glycine 86 and arginine 87 residues contribute differently to the structure and activity of the mature HIV-1 protease.

The structural and functional role of conserved residue G86 in HIV-1 protease (PR) was investigated by NMR and crystallographic analyses of substitution mutations of glycine to alanine and serine (PR{sub G86A} and PR{sub G86S}). While PR{sub G86S} had undetectable catalytic activity, PR{sub G86A} exhibited {approx}6000-fold lower catalytic activity than PR. {sup 1}H-{sup 15}N NMR correlation spectra revealed that PR{sub G86A} and PR{sub G86S} are dimeric, exhibiting dimer dissociation constants (K{sub d}) of {approx}0.5 and {approx}3.2 {micro}M, respectively, which are significantly lower than that seen for PR with R87K mutation (K{sub d} > 1 mM). Thus, the G86 mutants, despite being partially dimeric under the assay conditions, are defective in catalyzing substrate hydrolysis. NMR spectra revealed no changes in the chemical shifts even in the presence of excess substrate, indicating very poor binding of the substrate. Both NMR chemical shift data and crystal structures of PR{sub G86A} and PR{sub G86S} in the presence of active-site inhibitors indicated high structural similarity to previously described PR/inhibitor complexes, except for specific perturbations within the active site loop and around the mutation site. The crystal structures in the presence of the inhibitor showed that the region around residue 86 was connected to the active sitemore » by a conserved network of hydrogen bonds, and the two regions moved further apart in the mutants. Overall, in contrast to the role of R87 in contributing significantly to the dimer stability of PR, G86 is likely to play an important role in maintaining the correct geometry of the active site loop in the PR dimer for substrate binding and hydrolysis.« less
Developing stimulus presentation on mobile devices for a truly portable SSVEP-based BCI

This study integrates visual stimulus presentation and near real-time data processing on a mobile device (e.g. a Tablet or a cell-phone) to implement a steady-state visual evoked potentials (SSVEP)-based brain-computer interface (BCI). The goal of this study is to increase the practicability, portability and ubiquity of an SSVEP-based BCI for daily use. The accuracy of flickering frequencies on the mobile SSVEP BCI system was tested against that on a laptop/desktop used in our previous studies. This study then analyzed the power spectrum density of the electroencephalogram signals elicited by the visual stimuli rendered on the mobile BCIs. Finally, this study performed an online test with the Tablet-based BCI system and obtained an averaged information transfer rate of 33.87 bits/min in three subjects. The current integration leads to a truly practical and ubiquitous SSVEP BCI on mobile devices for real-life applications.
Fluorescence quenching studies with proteins.

Abstract A review is presented on the use of the technique of solute fluorescence quenching to study the structure and dynamics of proteins. A number of factors are discussed that must be considered in analyzing such data. Among these factors are the efficiency of the quenching process, the relative importance of static quenching, the heterogeneity of the emission, and the tendency of the quencher to interact with the protein.
Sulfonate-Containing Thiiranes as Selective Gelatinase Inhibitors

Matrix metalloproteinases (MMPs) are important zinc-dependent endopeptidases. Two members of this family of enzymes called gelatinases (MMP-2 and MMP-9) have been implicated in a number of human diseases, including cancer, neurological and cardiovascular diseases, and inflammation, to name a few. We describe in this report the preparation and evaluation of two structural types of thiirane inhibitors that show selectivity toward gelatinases. The biphenyl series targets both gelatinases, whereas the monophenyl analogues exhibit potent inhibition of only MMP-2. The latter structural type also exhibits improved water solubility and metabolic stability, both traits desirable for progress of these molecules forward in gelatinase-dependent animal models of disease.
Computer versus manual measurement of ST-segment deviation.

Abstract Total ST scores (sum of absolute deviations in all 12 electrocardiographic [ECG] leads) have been used for research purposes to estimate total ischemic burden and to predict reperfusion after thrombolytic therapy. Computerized monitoring systems are capable of measuring ST deviation to the 10-μV level, whereas humans are incapable of such precise resolution. The purpose of this study was to compare computer versus manual ST scores in 12-lead ECGs exhibiting ischemia and to compare interrater reliability of manual measurements between two experts. A total of 58 subjects with 100 μV or more ST deviation in one or more leads during percutaneous transluminal coronary angioplasty balloon inflation were selected for analysis. ST measurements were made at J + 80 ms, using the isoelectric line as a reference, and summed across all 12 leads. Manual measurements were made to a minimum of 50 μV by two independent reviewers blinded to the computer scores. Total ST scores were compared using paired t -tests, and Pearson coefficients were used to test the correlations. A high correlation was observed between the manual and computer measurements ( r = .96, P r = .96, P
Frequency of 12 mutations in 114 children with phenylketonuria in the Midwest region of the USA

Phenylalanine hydroxylase (PAH) is a liver-specific enzyme involved in the hydroxylation of phenylalanine (phe) to tyrosine. The deficiency of PAH results in excessive accumulation of phe in body fluids that leads to phenylketonuria (PKT). Among Caucasians, PKT affects 1 in 10000 live births and the carrier frequency of this inherited metabolic disorder is 1 in 50 (Scriver et al 1989). Clinically, this disorder is accompanied by neurological impairment and mental retardation of varying degree that seem to bear a relationship to the residual PAH activity in these patients (Okano et al 1991; Ramus et al 1993)
The feasibility of axiomatically-based expert systems.

Abstract We distinguish axiomatically-based expert systems, whose design and implementation are guided by one or more axiomatically-based theories of decision-making (e.g., decision theory, Bayesian probability theory, maximum entropy theory), from traditional expert systems. An analysis of the knowledge acquisition and computational needs of axiomatically-based expert systems is presented. An explicit quantitative comparison is made between the actual knowledge acquisition effort required to build an existing expert system, and the effort that would be required to build an anologous axiomatically-based advice system. The costs and benefits of the axiomatic approach are discussed. The analysis suggests that the small additional cost of knowledge acquisition for the axiomatic approach are outweighed by the long-term benefits this approach provides.
Dickens on disk

Malgre des erreurs l'edition electronique des romans de Charles Dickens permet certaines recherches jusqu'alors difficiles voire impossible
Linear Dichroism and the Transition Dipole Moment Orientation of the Carotenoid in the LH2 Antenna Complex in Membranes of Rhodopseudomonas acidophila Strain 10050

Linear dichroism (LD) of the carotenoid, rhodopin glucoside, and the 800 and 850 nm absorbing bacteriochlorophylls in the LH2 antenna complex from membranes of Rhodopseudomonas acidophilastrain 10050 squeezed in polyacrylamide gels is reported. A model is presented for computing the ratio of the LD-to-isotropic absorption (LD/A) for the pigments based on the crystal structure of the LH2 complex solved by X-ray diffraction methods. Semiempirical molecular orbital (MO) calculations have refined the structure of the protein-bound rhodopin glucoside and show that the transition moment of the carotenoid is not collinear with the long axis of the molecule. Rather, it is 9.1° off axis from the extended ﷿-electron conjugated chain. This rotation of the transition moment vector away from the structural long axis emerges as a result of the single/double bond alternation naturally present in all polyenes and carotenoids and is not due to environmental perturbations induced by binding of the molecule to the pigment-protein complex. Calculations of the intensity of polarized absorption for the rhodopin glucoside molecule predict a significant effect of the magnitude of the off-axis angle on the value of the observed LD/A. This paper employs semiempirical MO calculations and seeks to correlate the experimentally observed LD, which gives the orientation of the transition moment of the rhodopin glucoside in the membranes, with the X-ray diffraction results, which reveals the molecular structure of the carotenoid to atomic resolution.
Optimization of micellar liquid chromatographic separation of polycyclic aromatic hydrocarbons with the addition of second organic additive

The micellar liquid chromatographic (MLC) separations of polycyclic aromatic hydrocarbons (PAHs) were optimized for three micellar systems, cetyltrimethylammonium chloride (CTAC), dodecyltrimethylammonium chloride (DTAC), and sodium dodecylsulfate (SDS), with 1-pentanol as the only organic additive. A difference in the separation was observed between CTAC and SDS/DTAC. Under each optimized separation conditions, CTAC-modified mobile phase provides the least desirable separation, which is attributed to its longer carbon tail (C16 vs. C12). In addition to 1-pentanol, the main organic additive, a second organic additive (3% 1-propanol) in the micelle-modified mobile phase was found to enhance the resolution of PAH chromatographic peaks. However, the extent of the enhancement varies for the different micellar systems, with the greatest resolution improvement seen for CTAC, and little effect for shorter-tail SDS and DTAC. This study shows the potential use of second organic additive (1-propanol), to the main nonpolar additive (1-pentanol), in facilitating the MLC separation of larger nonpolar compounds.
DESIGN OF DIRECTIONAL RESIDUALS FOR OPTIMAL TESTABILITY

Abstract Abstract. Residuals in fault detection and diagnosis are usually designed with directional or structured properties to facilitate fault isolation. With directional residuals, best isolation is achieved if the residual directions are orthogonal. In the presence of noise, the residuals are subjected to statistical testing. Testing conditions are ideal if the Fisher information matrix of the residuals is diagonal. In this paper, we introduce a design technique which, subject to certain restrictions, provides orthogonal directions and diagonal information matrix simultaneously.
Revisiting the complexity of the ovarian cancer microenvironment--clinical implications for treatment strategies

Epithelial ovarian cancer (EOC) is the leading cause of death among gynecological malignancies in North American women. Given that EOC encompasses a broad class of tumors consisting of a variety of different histologic and molecular subtypes, which generates genetically and etiologically distinct tumors, several challenges arise during treatment of patients with this disease. Overlaying this complexity is the contribution of supporting cells, particularly stromal components such as fibroblasts and immune infiltrates that collectively create a microenvironment that promotes and enhances cancer progression. A notable example is the induction of angiogenesis, which occurs through the secretion of pro-angiogenic factors by both tumor and tumor-associated cells. The recent development of angiogenic inhibitors targeting tumor vasculature, which have been shown to improve patient outcome when combined with standard therapy, has launched a paradigm shift on how cancer patients should be treated. It is evident that future clinical practices will focus on the incorporation of therapies that antagonize the protumoral effects of such microenvironment contributors. Herein, an overview of the varying tumor-host interactions that influence tumor behavior will be discussed, in addition to the recent efforts undertaken to target these interactions and their potential to revolutionize EOC patient care.
Weighted Centroid Localization Algorithm: Theoretical Analysis and Distributed Implementation

Information about primary transmitter location is crucial in enabling several key capabilities in cognitive radio networks, including improved spatio-temporal sensing, intelligent location-aware routing, as well as aiding spectrum policy enforcement. Compared to other proposed non-interactive localization algorithms, the weighted centroid localization (WCL) scheme uses only the received signal strength information, which makes it simple to implement and robust to variations in the propagation environment. In this paper we present the first theoretical framework for WCL performance analysis in terms of its localization error distribution parameterized by node density, node placement, shadowing variance, correlation distance and inaccuracy of sensor node positioning. Using this analysis, we quantify the robustness of WCL to various physical conditions and provide design guidelines, such as node placement and spacing, for the practical deployment of WCL. We also propose a power-efficient method for implementing WCL through a distributed cluster-based algorithm, that achieves comparable accuracy with its centralized counterpart.
The Rule Against Perpetuities and the Law Commission’s Flawed Philosophy

The author considers the proposal of the Law Commission that the Rule against Perpetuities should be amended rather than abolished and emphasises the need for a balance between the freedom of the current generation and the freedom of future generations to control property. The article draws attention to the experience of Canada and the United States and suggests that experience undermines the Rule's economic rationale and that the Law Commission should consider recommending the Rule's abolition.
Constitutive Knockout of Kalirin-7 Leads to Increased Rates of Cocaine Self-Administration

Kalirin-7 (Kal7) is a Rho-guanine nucleotide exchange factor that is localized in neuronal postsynaptic densities. Kal7 interacts with the NR2B subunit of the NMDA receptor and regulates aspects of dendritic spine dynamics both in vitro and in vivo. Chronic treatment with cocaine increases dendritic spine density in the nucleus accumbens (NAc) of rodents and primates. Kal7 mRNA and protein are upregulated in the NAc following cocaine treatment, and the presence of Kal7 is necessary for the normal proliferation of dendritic spines following cocaine use. Mice that constitutively lack Kal7 [Kalirin-7 knockout mice (Kal7KO)] demonstrate increased locomotor sensitization to cocaine and a decreased place preference for cocaine. Here, using an intravenous cocaine self-administration paradigm, Kal7KO mice exhibit increased administration of cocaine at lower doses as compared with wild-type (Wt) mice. Analyses of mRNA transcript levels from the NAc of mice that self-administered saline or cocaine reveal that larger splice variants of the Kalrn gene are increased by cocaine more dramatically in Kal7KO mice than in Wt mice. Additionally, transcripts encoding the NR2B subunit of the NMDA receptor increased in Wt mice that self-administered cocaine but were unchanged in similarly experienced Kal7KO mice. These findings suggest that Kal7 participates in the reinforcing effects of cocaine, and that Kal7 and cocaine interact to alter the expression of genes related to critical glutamatergic signaling pathways in the NAc.
Coupling Factor Between the Magnetic and Mechanical Energy Domains in Electromagnetic Power Harvesting Applications

Micro-power generation is an area developing to support autonomous and battery-free wireless sensor networks and miniature electronic devices. Electromagnetic power harvesting is one of the main techniques for micro-power generation and it uses the relative motion between wire coils and miniature magnets to convert mechanical energy to electricity according to Faraday's law of induction. Crucial for the design and analysis of these power systems is the electromechanical coupling factor K , which describes the coupling between the mechanical and electromagnetic energy domains. In current literature K is defined as NBl : the product between the number of turns in the coil (N), the average magnetic induction field (B), and the length of a single coil turn (l) . This paper examines the validity of the current K definition and presents two case studies involving cylindrical permanent magnets and circular coil geometries to demonstrate its limitations. The case studies employ a numerical method for calculating K which uses the toroidal harmonics technique to determine the magnetic induction field in the vicinity of the cylindrical magnet.
Intact Survival in Extremely Low Birth Weight Infants After Delivery Room Resuscitation

Objective. None of the 20 previously reported infants weighing Study Design. We retrospectively reviewed the outcomes of all inborn infants with birth weights Results. Of the infants with birth weight Conclusions. Our results indicate that intact survival is possible for infants weighing
A three-dimensional linear model for breast tomosynthesis

Breast tomosynthesis alleviates the obscuring effects of overlapping breast tissue overlap in the diagnosis of breast cancer in screening mammography. In breast tomosynthesis, multiple projection images are acquired when the X-ray tube travels within a limited angular range, typically < 50deg. The projection images are reconstructed into tomographic slices that are parallel to the detector surface. Factors affecting the image quality of breast tomosynthesis include detector performance, acquisition geometry and reconstruction method. To investigate the impact of each factor, we built a three dimensional linear system model for breast tomsynthesis, validated it using experimental measurements of linear system parameters including noise power spectrum (NPS) and presampling modulation transfer function (MTF). Experiments were performed on a prototype breast tomosynthesis system equipped with an amorphous selenium (a-Se) digital mammography detector. Filtered backprojection (FBP) method was used for image reconstruction. Due to the limited angular range, the reconstructed 3D volume (512x512x40) had an anisotropic voxel size (0.085x0.085x1mm3). Scatter free uniform images were acquired for NPS analysis and an edge phantom was imaged for MTF measurements. It was found that the model agreed well with measurement, hence can be used to predict the imaging performance with different parameters and lead to optimization of breast tomosynthesis.
Gender-Specific Trends in the Value of Education and the Emerging Gender Gap in College Completion

Analysis of March Current Population Survey data from 1964 through 2002 shows that white women overtook white men in their rates of college completion and that this phenomenon occurred during a period in which women's standard-of-living gains from college completion grew at a faster rate than those for men. We assess whether these trends are related to changes in the value of education for men and women in terms of earnings returns to higher education, the probability of getting and staying married, education-related differences in family standard of living, and insurance against living in poverty. Although returns to a college education in the form of earnings remained higher for women than for men over the entire period, trends in these returns do not provide a plausible explanation for gender-specific trends in college completion. But when broader measures of material well-being are taken into account, women's returns to higher education appear to have risen faster than those of men.