Highly Sensitive Dual-Core Photonic Metal Fiber

In this study, we propose an all-solid cladding dual-core metal fiber (DC-MF) filled with toluene and ethanol for temperature sensing applications. Instead of using air holes in the cladding region, we employ fluorine doped silica glass to form an all-solid cladding. By selectively filling toluene and ethanol into three air holes near the core region, we investigate the temperature sensing characteristics numerically. Simulation results demonstrate that the average sensitivity of the temperature sensing can reach -11.64 and -7.41 nm/C within the temperature ranges of 0 to 70 C and -80 to 0 C, respectively, even with a short DC-MF length of 1.6 mm. The maximum sensitivity in the considered temperature ranges can reach up to -15 and -9 nm/C, respectively. Furthermore, the proposed temperature sensor exhibits insensitivity to hydrostatic pressure

2169 steel waveform experiments.

In support of LLNL efforts to develop multiscale models of a variety of materials, we have performed a set of eight gas gun impact experiments on 2169 steel (21% Cr, 6% Ni, 9% Mn, balance predominantly Fe). These experiments provided carefully controlled shock, reshock and release velocimetry data, with initial shock stresses ranging from 10 to 50 GPa (particle velocities from 0.25 to 1.05 km/s). Both windowed and free-surface measurements were included in this experiment set to increase the utility of the data set, as were samples ranging in thickness from 1 to 5 mm. Target physical phenomena included the elastic/plastic transition (Hugoniot elastic limit), the Hugoniot, any phase transition phenomena, and the release path (windowed and free-surface). The Hugoniot was found to be nearly linear, with no indications of the Fe-phase transition. Releases were non-hysteretic, and relatively consistent between 3- and 5-mm-thick samples (the 3 mm samples giving slightly lower wavespeeds on release). Reshock tests with explosively welded impactors produced clean results; those with glue bonds showed transient releases prior to the arrival of the reshock, reducing their usefulness for deriving strength information. The free-surface samples, which were steps on a single piece of steel, showed lower wavespeeds for thin (1 mm) samples than for thicker (2 or 4 mm) samples. A configuration used for the last three shots allows release information to be determined from these free surface samples. The sample strength appears to increase with stress from ~1 GPa to ~ 3 GPa over this range, consistent with other recent work but about 40% above the Steinberg model

Quantification of Lansoprazole in Oral Suspension by Ultra-High-Performance Liquid Chromatography Hybrid Ion-Trap Time-of-Flight Mass Spectrometry

An LC-MS/MS method was developed and validated to be used as a stability indicating assay for the study of a 3 mg/mL lansoprazole oral suspension. The method utilizes a UPLC (ultra-performance liquid chromatography) column and unique mass spectrometric detection (ion-trap time-of-flight (IT-TOF)) to achieve a sensitive (LOD 2 ng/mL), accurate, and reproducible quantification of lansoprazole. This method reports an intraday and interday coefficient of variation of 2.98 ± 2.17% (n = 5 for each concentration for each day) and 3.07 ± 0.89% (n = 20 for each concentration), respectively. Calibration curves (5–25 μg/mL) were found to be linear with an R2 value ranging from 0.9972 to 0.9991 on 4 different days. Accuracy of the assay, expressed as % error, ranged from 0.30 to 5.22%. This method is useful for monitoring the stability of lansoprazole in oral suspension

Reconciling Epidemiology and Social Justice in the Public Health Discourse Around the Sexual Networks of Black Men Who Have Sex With Men

Several studies have implicated the sexual networks of Black men who have sex with men (MSM) as facilitating disproportionally high rates of new HIV infections within this community. Although structural disparities place these networks at heightened risk for infection, HIV prevention science continues to describe networks as the cause for HIV disparities, rather than an effect of structures that pattern infection. We explore the historical relationship between public health and Black MSM, arguing that the current articulation of Black MSM networks is too often incomplete and counterproductive. Public health can offer a counternarrative that reconciles epidemiology with the social justice that informs our discipline, and that is required for an effective response to the epidemic among Black MSM

Mapping the auxin-binding site of auxin-binding protein 1

Auxin-binding protein 1 (ABP1) is a putative receptor for the class of plant growth hormones designated auxins of which indole-3-acetic acid (IAA) is the predominant endogenous member. ABP1 is a homodimeric glycoprotein consisting of subunits of 163 amino acid residues. We have performed a structural study of ABP1 that has localized a region along its primary sequence that is involved in hormone binding. We have used the photoaffinity labeling agent, 5-[7-3H]azidoindole-3-acetic acid (5-[3H]N3 IAA), an active auxin analog, to covalently label residues that are within, or near, the auxin-binding site. Photolabeled ABP1 was digested to completion with trypsin, and the resulting peptides were purified by reverse phase high performance liquid chromatography. When 5-[3H]N3 IAA was used at a concentration of 0.5 micromolar (one order of magnitude below the Kd for 5-N3 IAA) only one peptide was labeled at a high specific activity. Labeling was blocked by the presence of 50 micromolar IAA, indicating that the interaction is specific. Sequence analysis determined that this tryptic fragment was derived from Ile130 to Leu145 of ABP1. We suggest that residue Asp134 is the specific target of the photolabeling and is within 1.48 angstroms of the postulated hydrophobic platform of the auxin-binding site. We propose that Trp136 may serve as this hydrophobic platform in the binding site for the aromatic rings of auxins

Hydrogen diffusion in potassium intercalated graphite studied by quasielastic neutron scattering

The graphite intercalation compound KC24 adsorbs hydrogen gas at low temperatures up to a maximum stoichiometry of KC_(24)(H_2)_2, with a differential enthalpy of adsorption of approximately −9 kJ mol^(−1). The hydrogen molecules and potassium atoms form a two-dimensional condensed phase between the graphite layers. Steric barriers and strong adsorption potentials are expected to strongly hinder hydrogen diffusion within the host KC_24 structure. In this study, self-diffusion in a KC_(24)(H_2)_0.5 sample is measured experimentally by quasielastic neutron scattering and compared to values from molecular dynamics simulations. Self-diffusion coefficients are determined by fits of the experimental spectra to a honeycomb net diffusion model and found to agree well with the simulated values. The experimental H2 diffusion coefficients in KC_24 vary from 3.6 × 10^(−9) m^2 s^(−1) at 80 K to 8.5 × 10^(−9) m^2 s^(−1) at 110 K. The measured diffusivities are roughly an order of magnitude lower that those observed on carbon adsorbents, but compare well with the rate of hydrogen self-diffusion in molecular sieve zeolites

Integral Relaxation Time of Single-Domain Ferromagnetic Particles

The integral relaxation time \tau_{int} of thermoactivating noninteracting single-domain ferromagnetic particles is calculated analytically in the geometry with a magnetic field H applied parallel to the easy axis. It is shown that the drastic deviation of \tau_{int}^{-1} from the lowest eigenvalue of the Fokker-Planck equation \Lambda_1 at low temperatures, starting from some critical value of H, is the consequence of the depletion of the upper potential well. In these conditions the integral relaxation time consists of two competing contributions corresponding to the overbarrier and intrawell relaxation processes.Comment: 8 pages, 3 figure

Whole family-based physical activity promotion intervention: the Families Reporting Every Step to Health pilot randomised controlled trial protocol

Introduction Family-based physical activity (PA) interventions present a promising avenue to promote children’s activity; however, high-quality experimental research is lacking. This paper describes the protocol for the FRESH (Families Reporting Every Step to Health) pilot trial, a child-led family-based PA intervention delivered online. Methods and analysis FRESH is a three-armed, parallel-group, randomised controlled pilot trial using a 1:1:1 allocation ratio with follow-up assessments at 8 and 52 weeks postbaseline. Families will be eligible if a minimum of one child in school Years 3–6 (aged 7–11 years) and at least one adult responsible for that child are willing to participate. Family members can take part in the intervention irrespective of their participation in the accompanying evaluation and vice versa. Following baseline assessment, families will be randomly allocated to one of three arms: (1) FRESH; (2) pedometer-only or (3) no-intervention control. All family members in the pedometer-only and FRESH arms receive pedometers and generic PA promotion information. FRESH families additionally receive access to the intervention website; allowing participants to select step challenges to ‘travel’ to target cities around the world, log steps and track progress as they virtually globetrot. Control families will receive no treatment. All family members will be eligible to participate in the evaluation with two follow-ups (8 and 52 weeks). Physical (eg, fitness and blood pressure), psychosocial (eg, social support) and behavioural (eg, objectively measured family PA) measures will be collected at each time point. At 8-week follow-up, a mixed methods process evaluation will be conducted (questionnaires and family focus groups) assessing acceptability of the intervention and evaluation. FRESH families’ website engagement will also be explored. Ethics and dissemination This study received ethical approval from the Ethics Committee for the School of the Humanities and Social Sciences at the University of Cambridge. Findings will be disseminated via peer-reviewed publications, conferences and to participating families.This work was supported by the National Institute for Health Research Public Health Research Programme (project number 15/01/19). Intervention costs for the current study were supported by Active Norfolk and Suffolk County Council. Funding was also received from the Medical Research Council (project number MC_UU_12015/7)

Neurophysiology of epidurally evoked spinal cord reflexes in clinically motor-complete posttraumatic spinal cord injury

Increased use of epidural Spinal Cord Stimulation (eSCS) for the rehabilitation of spinal cord injury (SCI) has highlighted the need for a greater understanding of the properties of reflex circuits in the isolated spinal cord, particularly in response to repetitive stimulation. Here, we investigate the frequency-dependence of modulation of short- and long-latency EMG responses of lower limb muscles in patients with SCI at rest. Single stimuli could evoke short-latency responses as well as long-latency (likely polysynaptic) responses. The short-latency component was enhanced at low frequencies and declined at higher rates. In all muscles, the effects of eSCS were more complex if polysynaptic activity was elicited, making the motor output become an active process expressed either as suppression, tonic or rhythmical activity. The polysynaptic activity threshold is not constant and might vary with different stimulation frequencies, which speaks for its temporal dependency. Polysynaptic components can be observed as direct responses, neuromodulation of monosynaptic responses or driving the muscle activity by themselves, depending on the frequency level. We suggest that the presence of polysynaptic activity could be a potential predictor for appropriate stimulation conditions. This work studies the complex behaviour of spinal circuits deprived of voluntary motor control from the brain and in the absence of any other inputs. This is done by describing the monosynaptic responses, polysynaptic activity, and its interaction through its input–output interaction with sustain stimulation that, unlike single stimuli used to study the reflex pathway, can strongly influence the interneuron circuitry and reveal a broader spectrum of connectivity