Unconventional Metallic Magnetism in LaCrSb{3}

Neutron-diffraction measurements in LaCrSb{3} show a coexistence of ferromagnetic and antiferromagnetic sublattices below Tc=126 K, with ordered moments of 1.65(4) and 0.49(4) Bohr magnetons per formula unit, respectively (T=10 K), and a spin reorientation transition at ~95 K. No clear peak or step was observed in the specific heat at Tc. Coexisting localized and itinerant spins are suggested.Comment: PRL, in pres

Detection of Listeria monocytogenes in foods with a textile organic electrochemical transistor biosensor

Abstract: Foods contaminated by pathogens are responsible for foodborne diseases which have socioeconomic impacts. Many approaches have been extensively investigated to obtain specific and sensitive methods to detect pathogens in food, but they are often not easy to perform and require trained personnel. This work aims to propose a textile organic electrochemical transistor-based (OECT) biosensor to detect L. monocytogenes in food samples. The analyses were performed with culture-based methods, Listeria Precis™ method, PCR, and our textile OECT biosensor which used poly(3,4-ethylenedioxythiophene) (PEDOT):polystyrene sulfonate (PSS) (PEDOT:PSS) for doping the organic channel. Atomic force microscopy (AFM) was used to obtain topographic maps of the gold gate. The electrochemical activity on gate electrodes was measured and related to the concentration of DNA extracted from samples and hybridized to the specific capture probe immobilized onto the gold surface of the gate. This assay reached a limit of detection of 1.05 ng/μL, corresponding to 0.56 pM of L. monocytogenes ATCC 7644, and allowed the specific and rapid detection of L. monocytogenes in the analyzed samples. Keypoints: • Textile organic electrochemical transistors functionalized with a specific DNA probe • AFM topographic and surface potential maps of a functionalized gold gate surface • Comparison between the Listeria monocytogenes Precis™ method and an OECT biosenso

Barley beta-glucan promotes MnSOD expression and enhances angiogenesis under oxidative microenvironment

Manganese superoxide dismutase (MnSOD), a foremost antioxidant enzyme, plays a key role in angiogenesis. Barley-derived (1.3) β-d-glucan (β-d-glucan) is a natural water-soluble polysaccharide with antioxidant properties. To explore the effects of β-d-glucan on MnSOD-related angiogenesis under oxidative stress, we tested epigenetic mechanisms underlying modulation of MnSOD level in human umbilical vein endothelial cells (HUVECs) and angiogenesis in vitro and in vivo. Long-term treatment of HUVECs with 3% w/v β-d-glucan significantly increased the level of MnSOD by 200% ± 2% compared to control and by 50% ± 4% compared to untreated H2O2-stressed cells. β-d-glucan-treated HUVECs displayed greater angiogenic ability. In vivo, 24 hrs-treatment with 3% w/v β-d-glucan rescued vasculogenesis in Tg (kdrl: EGFP) s843Tg zebrafish embryos exposed to oxidative microenvironment. HUVECs overexpressing MnSOD demonstrated an increased activity of endothelial nitric oxide synthase (eNOS), reduced load of superoxide anion (O2-) and an increased survival under oxidative stress. In addition, β-d-glucan prevented the rise of hypoxia inducible factor (HIF)1-α under oxidative stress. The level of histone H4 acetylation was significantly increased by β-d-glucan. Increasing histone acetylation by sodium butyrate, an inhibitor of class I histone deacetylases (HDACs I), did not activate MnSOD-related angiogenesis and did not impair β-d-glucan effects. In conclusion, 3% w/v β-d-glucan activates endothelial expression of MnSOD independent of histone acetylation level, thereby leading to adequate removal of O2-, cell survival and angiogenic response to oxidative stress. The identification of dietary β-d-glucan as activator of MnSOD-related angiogenesis might lead to the development of nutritional approaches for the prevention of ischemic remodelling and heart failure

Optimal discretization of grounding systems applying Maxwell's subareas method

This paper presents a method for evaluating the optimal number n of equivalent sources needed for simulating grounding systems by the Maxwell's subareas method. It is well known that the number of elements in which electrodes are subdivided plays a role on the accuracy and reliability of results (as well as on computational time). Previous studies, accomplished through iterative calculations (performed with different segmentations), led mostly to some recommended practices for the identification of lower and upper bounds for n. The procedure proposed in this paper allows for predicting the optimal n in a single process. The method starts from the identification of a set of appropriate scalar functions, which heuristically express a relation between the number of subareas and the accuracy of the results (earth resistance and earth surface voltages) computed applying the Maxwell's subareas method. Then, a multi-objective optimization process evaluates the number n* that maximizes that accuracy

Electron correlation in C_(4N+2) carbon rings: aromatic vs. dimerized structures

The electronic structure of C_(4N+2) carbon rings exhibits competing many-body effects of Huckel aromaticity, second-order Jahn-Teller and Peierls instability at large sizes. This leads to possible ground state structures with aromatic, bond angle or bond length alternated geometry. Highly accurate quantum Monte Carlo results indicate the existence of a crossover between C_10 and C_14 from bond angle to bond length alternation. The aromatic isomer is always a transition state. The driving mechanism is the second-order Jahn-Teller effect which keeps the gap open at all sizes.Comment: Submitted for publication: 4 pages, 3 figures. Corrected figure

A-PHOT: a new, versatile code for precision aperture photometry

We present A-PHOT, a new publicly available code for performing aperture photometry on astronomical images, that is particularly well suited for multi-band extragalactic surveys. A-PHOT estimates the fluxes emitted by astronomical objects within a chosen set of circular or elliptical apertures. Unlike other widely used codes, it runs on predefined lists of positions, allowing for repeated measurements on the same list of objects on different images. This can be very useful when forced photometric measurement on a given position is needed. A-PHOT can also estimate morphological parameters and a local background flux, and compute on-the-fly individual optimized elliptical apertures, in which the signal-to-noise ratio is maximized. We check the performance of A-PHOT on both synthetic and real test datasets: we explore a simulated case of a space-based high-resolution imaging dataset, investigating the input parameter space to optimize the accuracy of the performance, and we exploit the CANDELS GOODS-South data to compare the A-PHOT measurements with those from the survey legacy catalogs, finding good agreement overall. A-PHOT proves to a useful and versatile tool for quickly extracting robust and accurate photometric measurements and basic morphological information of galaxies and stars, with the advantage of allowing for various measurements of fluxes at any chosen position without the need of a full detection run, and for determining the basic morphological features of the sources.Comment: 10 pages, 9 figure

Phase Inhomogeneity of the Itinerant Ferromagnet MnSi at High Pressures

The pressure induced quantum phase transition of the weakly itinerant ferromagnet MnSi is studied using zero-field $^{29}Si$ NMR spectroscopy and relaxation. Below $P^*\approx 1.2GPa$, the intensity of the signal and the nuclear spin-lattice relaxation is independent of pressure, even though the amplitude of the magnetization drops by 20% from the ambient pressure amplitude. For $P>P^*$, the decreasing intensity within the experimentally detectable bandwidth signals the onset of an inhomogeneous phase that persists to the highest pressure measured, $P\ge 1.75GPa$, which is well beyond the known critical pressure $P_c=1.46GPa$. Implications for the non-Fermi Liquid behavior observed for $P>P_c$ are discussed.Comment: 4 pages, 4 figure

Fatal herpesvirus-6 encephalitis in a recipient of a T-cell-depleted peripheral blood stem cell transplant from a 3-loci mismatched related donor

Human herpesvirus-6 (HHV-6), like all the other herpes viruses, remains latent in host cells after primary infection but can be reactivated In immuno-compromised patients causing fever, skin rash, bone marrow (BM) suppression, pneumonitis, Sinusitis and meningoencephalitis. We describe the case of a man with chronic myelogenous leukemia who developed encephalitis associated with acute graft-versus-host disease two months after a T-cell-depleted mismatched peripheral blood stem cell transplant. Magnetic resonance images of the brain revealed multiple bilateral foci of signal abnormality. HHV-6 was the only pathogen detected in cerebrospinal fluid by PCR. treatment with both ganciclovir and foscarnet was unsuccessful and the patient gradually deteriorated and died. Other cases of HHV-6 encephalitis after bone marrow transplantation are reviewed

Enhanced Optical 13C Hyperpolarization in Diamond Treated by High-Temperature Rapid Thermal Annealing

Methods of optical dynamic nuclear polarization open the door to the replenishable hyperpolarization of nuclear spins, boosting their nuclear magnetic resonance/imaging signatures by orders of magnitude. Nanodiamond powder rich in negatively charged nitrogen vacancy defect centers has recently emerged as one such promising platform, wherein 13C nuclei can be hyperpolarized through the optically pumped defects completely at room temperature. Given the compelling possibility of relaying this 13C polarization to nuclei in external liquids, there is an urgent need for the engineered production of highly “hyperpolarizable” diamond particles. Here, a systematic study of various material dimensions affecting optical 13C hyperpolarization in diamond particles is reported on. It is discovered surprisingly that diamond annealing at elevated temperatures ∼1720 °C has remarkable effects on the hyperpolarization levels enhancing them by above an order of magnitude over materials annealed through conventional means. It is demonstrated these gains arise from a simultaneous improvement in NV− electron relaxation/coherence times, as well as the reduction of paramagnetic content, and an increase in 13C relaxation lifetimes. This work suggests methods for the guided materials production of fluorescent, 13C hyperpolarized, nanodiamonds and pathways for their use as multimodal (optical and magnetic resonance) imaging and hyperpolarization agents