Stallion sperm quality after combined ejaculate fractionation and colloidal centrifugation

This study investigated the possible additive benefit of ejaculate fractionation and colloidal centrifugation on stallion sperm quality. Using an open-end artificial vagina, the sperm-rich fraction (FRAC-1) was separated from the rest of the ejaculate (FRAC-2) and a third sperm sample representing the combined ejaculate was reconstituted post-ejaculation (RAW). Each semen sample was processed for colloidal centrifugation. The percentage of abnormal spermatozoa was 17.8 ± 7.0% in RAW and 14.6 ± 9.5% in FRAC-1 but decreased to 11.4 ± 4.7% and 9.6 ± 6.9% respectively, after colloidal centrifugation. A sperm DNA fragmentation index of 10.9 ± 5.1% was observed in RAW and 7.5 ± 2.4% in FRAC-1 semen collected with the AV but this decreased to 7.8 ± 2.8% and 5.2 ± 2.3% after colloidal centrifugation. The rate of increase in sperm DNA fragmentation during the first 6 h of incubation at 37 ºC was 1.8 ± 0.9% per hour in RAW semen and 2.0 ± 2.0% per hour in FRAC-1 but this significantly decreased to 1.3 ± 1.4% and 0.9 ± 0.8% respectively after colloidal centrifugation. While stallion seminal characteristics can be improved using colloidal centrifugation, further enhancement is possible if the ejaculate is initially fractionatedThis research was supported by the Spanish Ministry of Economy and Competitiveness, MINECO (BFU-2013-44290-R

Liver fat in adults with GH deficiency: comparison to matched controls and the effect of GH replacement

CONTEXT: Existing data regarding the association between growth hormone deficiency (GHD) and liver fat content are conflicting. OBJECTIVE: We aimed i) to assess intrahepatocellular lipid (IHCL) content in hypopituitary adults with GHD compared to matched controls and ii) to evaluate the effect of growth hormone (GH) replacement on IHCL content. DESIGN: Cross-sectional comparison and controlled intervention study. PATIENTS, PARTICIPANTS: Cross-sectional comparison: 22 hypopituitary adults with GHD and 44 healthy controls matched for age, BMI, gender and ethnicity. Intervention study: 9 GHD patients starting GH replacement (GH Rx group), 9 GHD patients not starting replacement therapy (non-GH Rx group). INTERVENTION: Intervention study:GH replacement for 6 months in the GH Rx group, dosage was titrated to achieve normal IGF-1 levels. MAIN OUTCOME MEASURES: IHCL content determined by proton magnetic resonance spectroscopy (1 H MRS). RESULTS: Cross-sectional comparison: There was no difference in IHCL content between GHD patients and healthy controls (1.89% (0.30, 4.03) vs. 1.14% (0.22, 2.32); p=0.2), the prevalence of patients with hepatic steatosis (IHCL of ≥ 5.56%) was similar in the two groups (22.7% vs. 15.9%; chi square probability = 0.4). Intervention study: The change in IHCL content over 6 months did not differ between the GH Rx group and the non-GH Rx group (-0.63 ± 4.53% vs. +0.11 ± 1.46%; p=0.6). CONCLUSIONS: In our study liver fat content and the prevalence of hepatic steatosis did not differ between hypopituitary adults with GHD and matched controls. In GHD patients GH replacement had no effect on liver fat content

“Don’t let the trial kill the intervention”: How can researchers and care home teams implement complex intervention trials in care homes?

There is a need for a context-specific sustainable model for conduct of high-quality research in care homes Implementation of research interventions in care homes needs co-design, good relationships, understanding the context and funding A framework can provide the basis to build trust between researchers, care home residents, families and staff

YMP Engineered Barrier Systems Scaled Ventilation Testing

Yucca Mountain, approximately 100 miles northwest of Las Vegas, Nevada, has been selected as the site for the nation's first geologic repository for high level nuclear waste. The Yucca Mountain Project (YMP) is currently developing the design for the underground facilities. Ventilation is a key component of the design as a way to maintain the desired thermal conditions in the emplacement drifts prior to closure. As a means of determining the effects of continuous ventilation on heat removal from the emplacement drifts two series of scaled ventilation tests have been performed. Both test series were performed in the DOE/North Las Vegas Atlas facility. The tests provided scaled (nominally 25% of the full scale emplacement drift design) thermal and flow process data that will be used to validate YMP heat and mass transport codes. The Phase I Ventilation Test series evaluated the ability of ambient ventilation air to remove energy under varying flow and input power conditions. The Phase II Ventilation Test series evaluated the ability of pre-conditioned ventilation air to remove energy under varying flow, input temperature and moisture content, and simulated waste package input power conditions. Twenty-two distinct ventilation tests were run

Evidence for chiral superconductivity on a silicon surface

Tin adatoms on a Si(111) substrate with a one-third monolayer coverage form a two-dimensional triangular lattice with one unpaired electron per site. These electrons order into an antiferromagnetic Mott-insulating state, but doping the Sn layer with holes creates a two-dimensional conductor that becomes superconducting at low temperatures. Although the pairing symmetry of the superconducting state is currently unknown, the combination of repulsive interactions and frustration inherent in the triangular adatom lattice opens up the possibility of a chiral order parameter. Here we study the superconducting state of Sn/Si(111) using scanning tunnelling microscopy, scanning tunnelling spectroscopy and quasiparticle interference imaging. We find evidence for a doping-dependent superconducting critical temperature with a fully gapped order parameter, the presence of time-reversal symmetry breaking and a strong enhancement in zero-bias conductance near the edges of the superconducting domains. Although each individual piece of evidence could have a more mundane interpretation, our combined results suggest the possibility that Sn/Si(111) is an unconventional chiral d-wave superconducto

Spin-polarized current amplification and spin injection in magnetic bipolar transistors

The magnetic bipolar transistor (MBT) is a bipolar junction transistor with an equilibrium and nonequilibrium spin (magnetization) in the emitter, base, or collector. The low-injection theory of spin-polarized transport through MBTs and of a more general case of an array of magnetic {\it p-n} junctions is developed and illustrated on several important cases. Two main physical phenomena are discussed: electrical spin injection and spin control of current amplification (magnetoamplification). It is shown that a source spin can be injected from the emitter to the collector. If the base of an MBT has an equilibrium magnetization, the spin can be injected from the base to the collector by intrinsic spin injection. The resulting spin accumulation in the collector is proportional to $\exp(qV_{be}/k_BT)$, where $q$ is the proton charge, $V_{be}$ is the bias in the emitter-base junction, and $k_B T$ is the thermal energy. To control the electrical current through MBTs both the equilibrium and the nonequilibrium spin can be employed. The equilibrium spin controls the magnitude of the equilibrium electron and hole densities, thereby controlling the currents. Increasing the equilibrium spin polarization of the base (emitter) increases (decreases) the current amplification. If there is a nonequilibrium spin in the emitter, and the base or the emitter has an equilibrium spin, a spin-valve effect can lead to a giant magnetoamplification effect, where the current amplifications for the parallel and antiparallel orientations of the the equilibrium and nonequilibrium spins differ significantly. The theory is elucidated using qualitative analyses and is illustrated on an MBT example with generic materials parameters.Comment: 14 PRB-style pages, 10 figure

Theory of spin-polarized bipolar transport in magnetic p-n junctions

The interplay between spin and charge transport in electrically and magnetically inhomogeneous semiconductor systems is investigated theoretically. In particular, the theory of spin-polarized bipolar transport in magnetic p-n junctions is formulated, generalizing the classic Shockley model. The theory assumes that in the depletion layer the nonequilibrium chemical potentials of spin up and spin down carriers are constant and carrier recombination and spin relaxation are inhibited. Under the general conditions of an applied bias and externally injected (source) spin, the model formulates analytically carrier and spin transport in magnetic p-n junctions at low bias. The evaluation of the carrier and spin densities at the depletion layer establishes the necessary boundary conditions for solving the diffusive transport equations in the bulk regions separately, thus greatly simplifying the problem. The carrier and spin density and current profiles in the bulk regions are calculated and the I-V characteristics of the junction are obtained. It is demonstrated that spin injection through the depletion layer of a magnetic p-n junction is not possible unless nonequilibrium spin accumulates in the bulk regions--either by external spin injection or by the application of a large bias. Implications of the theory for majority spin injection across the depletion layer, minority spin pumping and spin amplification, giant magnetoresistance, spin-voltaic effect, biasing electrode spin injection, and magnetic drift in the bulk regions are discussed in details, and illustrated using the example of a GaAs based magnetic p-n junction.Comment: 36 pages, 11 figures, 2 table

The G0 Experiment: Apparatus for Parity-Violating Electron Scattering Measurements at Forward and Backward Angles

In the G0 experiment, performed at Jefferson Lab, the parity-violating elastic scattering of electrons from protons and quasi-elastic scattering from deuterons is measured in order to determine the neutral weak currents of the nucleon. Asymmetries as small as 1 part per million in the scattering of a polarized electron beam are determined using a dedicated apparatus. It consists of specialized beam-monitoring and control systems, a cryogenic hydrogen (or deuterium) target, and a superconducting, toroidal magnetic spectrometer equipped with plastic scintillation and aerogel Cerenkov detectors, as well as fast readout electronics for the measurement of individual events. The overall design and performance of this experimental system is discussed.Comment: Submitted to Nuclear Instruments and Method

Interiorized Feminism and Gendered Nostalgia of The ‘Daughter Generation’ in Ning Ying's Perpetual Motion

This is the author's accepted manuscript. The original publication is available at http://dx.doi.org/10.1386/jcc.5.3.253_1Ning Ying’s 2006 film Wuqiong dong/Perpetual Motion can be regarded as her first attempt to explore the genre of ‘women’s film’. Deviating from her previous neo-realist style, this film seeks to cultivate an alternative cinematic practice through developing a heavy-handed negative aesthetics. Ning Ying interiorizes the filmic exploration of female subjectivity in an enclosed time and space, which is constantly haunted by a spectral aesthetics characterized by audio-visual allusions to loss, grave, ruins and ghosts. However, the film’s radical content and alternative aesthetics are, ironically, packaged in prevailing consumer aesthetics and commodity fetishism on and off the silver screen. All these competing drives and accounts render the film a contested narrative constantly oscillating between avant-garde feminism and domestic melodrama, and between a register of disintegrating sisterhood and a celebrity scandal of adultery. This article examines the discursive and aesthetic innovations, contradictions and limits of Ning Ying’s cinematic feminism