Monitoring surface resonances on Co2MnSi(100) by spin-resolved photoelectron spectroscopy

The magnitude of the spin polarization at the Fermi level of ferromagnetic materials at room temperature is a key property for spintronics. Investigating the Heusler compound Co$_2$MnSi a value of 93$\%$ for the spin polarization has been observed at room temperature, where the high spin polarization is related to a stable surface resonance in the majority band extending deep into the bulk. In particular, we identified in our spectroscopical analysis that this surface resonance is embedded in the bulk continuum with a strong coupling to the majority bulk states. The resonance behaves very bulk-like, as it extends over the first six atomic layers of the corresponding (001)-surface. Our study includes experimental investigations, where the bulk electronic structure as well as surface-related features have been investigated using spin-resolved photoelectron spectroscopy (SR-UPS) and for a larger probing depth spin-integrated high energy x-ray photoemission spectroscopy (HAXPES). The results are interpreted in comparison with first-principles band structure and photoemission calculations which consider all relativistic, surface and high-energy effects properly.Comment: 9 pages, 8 figures, Heusler alloy, electronic structure and photoemissio

Role of the Netrin-like Domain of Procollagen C-Proteinase Enhancer-1 in the Control of Metalloproteinase Activity

The netrin-like (NTR) domain is a feature of several extracellular proteins, most notably the N-terminal domain of tissue inhibitors of metalloproteinases (TIMPs), where it functions as a strong inhibitor of matrix metalloproteinases and some other members of the metzincin superfamily. The presence of a C-terminal NTR domain in procollagen C-proteinase enhancers (PCPEs), proteins that stimulate the activity of astacin-like tolloid proteinases, raises the possibility that this might also have inhibitory activity. Here we show that both long and short forms of the PCPE-1 NTR domain, the latter beginning at the N-terminal cysteine known to be critical for TIMP activity, show no inhibition, at micromolar concentrations, of several members of the metzincin superfamily, including matrix metalloproteinase-2, bone morphogenetic protein-1 (a tolloid proteinase), and different ADAMTS (a disintegrin and a metalloproteinase with thrombospondin motifs) proteinases from the adamalysin family. In contrast, we report that the NTR domain within PCPE-1 leads to superstimulation of bone morphogenetic protein-1 activity in the presence of heparin and heparan sulfate. These observations point to a new mechanism whereby binding to cell surface-associated or extracellular heparin-like sulfated glycosaminoglycans might provide a means to accelerate procollagen processing in specific cellular and extracellular microenvironments

Re-establishing glacier monitoring in Kyrgyzstan and Uzbekistan, Central Asia

Glacier mass loss is among the clearest indicators of atmospheric warming. The observation of these changes is one of the major objectives of the international climate monitoring strategy developed by the Global Climate Observing System (GCOS). Long-term glacier mass balance measurements are furthermore the basis for calibrating and validating models simulating future runoff of glacierised catchments. This is essential for Central Asia, which is one of the driest continental regions of the Northern Hemisphere. In the highly populated regions, water shortage due to decreased glacierisation potentially leads to pronounced political instability, drastic ecological changes and endangered food security. As a consequence of the collapse of the former Soviet Union, however, many valuable glacier monitoring sites in the Tien Shan and Pamir Mountains were abandoned. In recent years, multinational actors have re-established a set of important in situ measuring sites to continue the invaluable long-term data series. This paper introduces the applied monitoring strategy for selected glaciers in the Kyrgyz and Uzbek Tien Shan and Pamir, highlights the existing and the new measurements on these glaciers, and presents an example for how the old and new data can be combined to establish multi-decadal mass balance time series. This is crucial for understanding the impact of climate change on glaciers in this region

Direct observation of half-metallicity in the Heusler compound Co2MnSi

Ferromagnetic thin films of Heusler compounds are highly relevant for spintronic applications owing to their predicted half-metallicity, that is, 100% spin polarization at the Fermi energy. However, experimental evidence for this property is scarce. Here we investigate epitaxial thin films of the compound Co2MnSi in situ by ultraviolet-photoemission spectroscopy, taking advantage of a novel multi-channel spin filter. By this surface sensitive method, an exceptionally large spin polarization of (93(-11)(+7)) % at room temperature is observed directly. As a more bulk sensitive method, additional ex situ spin-integrated high energy X-ray photoemission spectroscopy experiments are performed. All experimental results are compared with advanced band structure and photoemission calculations which include surface effects. Excellent agreement is obtained with calculations, which show a highly spin polarized bulk-like surface resonance ingrained in a half metallic bulk band structure

Glioblastoma-induced attraction of endogenous neural precursor cells is associated with improved survival

Neural precursor cells contribute to adult neurogenesis and to limited attempts of brain repair after injury. Here we report that in a murine experimental glioblastoma model, endogenous neural precursors migrate from the subventricular zone toward the tumor and surround it. The association of endogenous precursors with syngenic tumor grafts was observed, after injecting red fluorescent protein-labeled G261 cells into the caudate-putamen of transgenic mice, which express green fluorescent protein under a promoter for nestin (nestin-GFP). Fourteen days after inoculation, the nestin-GFP cells surrounded the tumors in several cell layers and expressed markers of early noncommitted and committed precursors. Nestin-GFP cells were further identified by a characteristic membrane current pattern as recorded in acute brain slices. 5-bromo-2-deoxyuridine labeling and dye tracing experiments revealed that the tumor-associated precursors originated from the subventricular zone. Moreover, in cultured explants from the subventricular zone, the neural precursors showed extensive tropism for glioblastomas. Tumor-induced endogenous precursor cell accumulation decreased with age of the recipient; this correlated with increased tumor size and shorter survival times in aged mice. Coinjection of glioblastoma cells with neural precursors improved the survival time of old mice to a level similar to that in young mice. Coculture experiments showed that neural precursors suppressed the rapid increase in tumor cell number, which is characteristic of glioblastoma, and induced glioblastoma cell apoptosis. Our results indicate that tumor cells attract endogenous precursor cells; the presence of precursor cells is antitumorigenic; and this cellular interaction decreases with aging

Bone CLARITY: Clearing, imaging, and computational analysis of osteoprogenitors within intact bone marrow

Bone tissue harbors unique and essential physiological processes, such as hematopoiesis, bone growth, and bone remodeling. To enable visualization of these processes at the cellular level in an intact environment, we developed “Bone CLARITY,” a bone tissue clearing method. We used Bone CLARITY and a custom-built light-sheet fluorescence microscope to detect the endogenous fluorescence of Sox9-tdTomato+ osteoprogenitor cells in the tibia, femur, and vertebral column of adult transgenic mice. To obtain a complete distribution map of these osteoprogenitor cells, we developed a computational pipeline that semiautomatically detects individual Sox9-tdTomato+ cells in their native three-dimensional environment. Our computational method counted all labeled osteoprogenitor cells without relying on sampling techniques and displayed increased precision when compared with traditional stereology techniques for estimating the total number of these rare cells. We demonstrate the value of the clearing-imaging pipeline by quantifying changes in the population of Sox9-tdTomato–labeled osteoprogenitor cells after sclerostin antibody treatment. Bone tissue clearing is able to provide fast and comprehensive visualization of biological processes in intact bone tissue

Inflammatory proteins in plasma are associated with severity of Alzheimer's disease.

Published onlineComparative StudyResearch Support, Non-U.S. Gov'tThis is a freely-available open access publication. Please cite the published version which is available via the DOI link in this record.Markers of Alzheimer's disease (AD) are being widely sought with a number of studies suggesting blood measures of inflammatory proteins as putative biomarkers. Here we report findings from a panel of 27 cytokines and related proteins in over 350 subjects with AD, subjects with Mild Cognitive Impairment (MCI) and elderly normal controls where we also have measures of longitudinal change in cognition and baseline neuroimaging measures of atrophy. In this study, we identify five inflammatory proteins associated with evidence of atrophy on MR imaging data particularly in whole brain, ventricular and entorhinal cortex measures. In addition, we observed six analytes that showed significant change (over a period of one year) in people with fast cognitive decline compared to those with intermediate and slow decline. One of these (IL-10) was also associated with brain atrophy in AD. In conclusion, IL-10 was associated with both clinical and imaging evidence of severity of disease and might therefore have potential to act as biomarker of disease progression.National Institute for Health Research (NIHR) Mental Health Biomedical Research Centre and Dementia Biomedical Research Unit at South London and Maudsley NHS Foundation Trust and King’s College LondonEuropean Union of the Sixth Framework progra

Use of polyethylene glycol coatings for optical fibre humidity sensing

Humidity induced change in the refractive index and thickness of the polyethylene glycol (PEG) coatings are in situ investigated for a range from 10 to 95%, using an optical waveguide spectroscopic technique. It is experimentally demonstrated that, upon humidity change, the optical and swelling characteristics of the PEG coatings can be employed to build a plastic fibre optic humidity sensor. The sensing mechanism is based on the humidity induced change in the refractive index of the PEG film, which is directly coated onto a polished segment of a plastic optical fibre with dip-coating method. It is observed that PEG, which is a highly hydrophilic material, shows no monotonic linear response to humidity but gives different characteristics for various ranges of humidity levels both in index of refraction and in thickness. It undergoes a physical phase change from a semi-crystal line structure to a gel one at around 80% relative humidity. At this phase change point, a drastic decrease occurs in the index of refraction as well as a drastic increase in the swelling of the PEG film. In addition, PEG coatings are hydrogenated in a vacuum chamber. It is observed that the hydrogen has a preventing effect on the humidity induced phase change in PEG coatings. Finally, the possibility of using PEG coatings in construction of a real plastic fibre optic humidity sensor is discussed. (C) 2008 The Optical Society of Japan

A Prospective Multicenter SPOG 2003 FN Study of Microbiologically Defined Infections in Pediatric Cancer Patients with Fever and Neutropenia.

BACKGROUND: Fever and neutropenia (FN) often complicate anticancer treatment and can be caused by potentially fatal infections. Knowledge of pathogen distribution is paramount for optimal patient management. METHODS: Microbiologically defined infections (MDI) in pediatric cancer patients presenting with FN by nonmyeloablative chemotherapy enrolled in a prospective multi-center study were analyzed. Effectiveness of empiric antibiotic therapy in FN episodes with bacteremia was assessed taking into consideration recently published treatment guidelines for pediatric patients with FN. RESULTS: MDI were identified in a minority (22%) of pediatric cancer patients with FN. In patients with, compared to without MDI, fever (median, 5 [IQR 3-8] vs. 2 [IQR1-3] days, p < 0.001) and hospitalization (10 [6-14] vs. 5 [3-8] days, p < 0.001) lasted longer, transfer to the intensive care unit was more likely (13 of 95 [14%] vs. 7 of 346 [2.0%], p < 0.001), and antibiotics were given longer (10 [7-14] vs. 5 [4-7], p < 0.001). Empiric antibiotic therapy in FN episodes with bacteremia was highly effective if not only intrinsic and reported antimicrobial susceptibilities were considered but the purposeful omission of coverage for coagulase negative staphylococci and enterococci was also taken into account (81% [95%CI 68 - 90] vs. 96.6% [95%CI 87 - 99.4], p = 0.004) CONCLUSIONS: MDI were identified in a minority of FN episodes but they significantly affected management and the clinical course of pediatric cancer patients. Compliance with published guidelines was associated with effectiveness of empiric antibiotic therapy in FN episodes with bacteremia

Folate deficiency induces neurodegeneration and brain dysfunction in mice lacking uracil DNA glycosylase

Folate deficiency and resultant increased homocysteine levels have been linked experimentally and epidemiologically with neurodegenerative conditions like stroke and dementia. Moreover, folate deficiency has been implicated in the pathogenesis of psychiatric disorders, most notably depression. We hypothesized that the pathogenic mechanisms include uracil misincorporation and, therefore, analyzed the effects of folate deficiency in mice lacking uracil DNA glycosylase (Ung-/-) versus wild-type controls. Folate depletion increased nuclear mutation rates in Ung-/- embryonic fibroblasts, and conferred death of cultured Ung-/- hippocampal neurons. Feeding animals a folate-deficient diet (FD) for 3 months induced degeneration of CA3 pyramidal neurons in Ung-/- but not Ung+/+ mice along with decreased hippocampal expression of brain-derived neurotrophic factor protein and decreased brain levels of antioxidant glutathione. Furthermore, FD induced cognitive deficits and mood alterations such as anxious and despair-like behaviors that were aggravated in Ung-/- mice. Independent of Ung genotype, FD increased plasma homocysteine levels, altered brain monoamine metabolism, and inhibited adult hippocampal neurogenesis. These results indicate that impaired uracil repair is involved in neurodegeneration and neuropsychiatric dysfunction induced by experimental folate deficiency