Anisotropic magnetoresistance of single-crystal HoNi2B2C and the interplay of magnetic and superconducting order

Journals published by the American Physical Society can be found at http://journals.aps.org/The in-plane resistivity and magnetization measurements as a function of the magnitude and direction of the magnetic field and the temperature are reported for single-crystal samples of the HoNi2B2C magnetic superconductor. Features corresponding to several distinct magnetic phases and the coexistence of superconductivity with two of the magnetic phases are observed. Contrary to previous measurements for polycrystalline samples, reentrant superconductivity is not observed in the absence of a field for these samples. The measurements indicate an extremely rich interplay between superconductivity and different magnetic structures that can be influenced by field, temperature, and current. The results correlate quantitatively with and complement previous determinations of the magnetic phase diagram and qualitatively with determinations of the superconducting phases by measurements of the single-crystal magnetization and heat capacity. HoNi2B2C is highly anisotropic, and phase diagrams for the field along the (100) and (001) directions are presented

Angular dependence of metamagnetic transitions in HoNi2B2C

Journals published by the American Physical Society can be found at http://journals.aps.org/Detailed measurements of M(2 K, H, theta) of HoNi2B2C, where theta is the angle that the applied field H makes with the [110] axis while remaining perpendicular to the crystallographic c axis, reveal three metamagnetic transitions with angular dependences H-c1 = (4.1 +/- 0.1 kG)/cos(theta), H-c2 = 8.4 +/- 0.2 kG/cos(phi), and H-c3 = (6.6 +/- 0.2 kG)/sin(phi), where phi = theta-45 is the angle from the [100] axis. The high-field saturated moment, M(sat) approximate to 10 mu(B)cos theta is consistent with the local moments being confined to the [110] direction. The locally saturated moments for fields between H-ci (i = 1, 2, 3) also manifest angular dependences that are consistent with combinations of local moments along [110] axes. Analysis of these data lead us to infer that the net distribution of moments is (up arrow down arrow up arrow down arrow up arrow down arrow) for H up arrow up arrow-->) for H-c2 up arrow up arrow-->) for H-c2 H-c3

Compared to conventional, ecological intensive management promotes beneficial proteolytic soil microbial communities for agro-ecosystem functioning under climate change-induced rain regimes

Projected climate change and rainfall variability will affect soil microbial communities, biogeochemical cycling and agriculture. Nitrogen (N) is the most limiting nutrient in agroecosystems and its cycling and availability is highly dependent on microbial driven processes. In agroecosystems, hydrolysis of organic nitrogen (N) is an important step in controlling soil N availability. We analyzed the effect of management (ecological intensive vs. conventional intensive) on N-cycling processes and involved microbial communities under climate change-induced rain regimes. Terrestrial model ecosystems originating from agroecosystems across Europe were subjected to four different rain regimes for 263 days. Using structural equation modelling we identified direct impacts of rain regimes on N-cycling processes, whereas N-related microbial communities were more resistant. In addition to rain regimes, management indirectly affected N-cycling processes via modifications of N-related microbial community composition. Ecological intensive management promoted a beneficial N-related microbial community composition involved in N-cycling processes under climate change-induced rain regimes. Exploratory analyses identified phosphorus-associated litter properties as possible drivers for the observed management effects on N-related microbial community composition. This work provides novel insights into mechanisms controlling agro-ecosystem functioning under climate change

A cluster randomized trial of standard quality improvement versus patient-centered interventions to enhance depression care for African Americans in the primary care setting: study protocol NCT00243425

<p>Abstract</p> <p>Background</p> <p>Several studies document disparities in access to care and quality of care for depression for African Americans. Research suggests that patient attitudes and clinician communication behaviors may contribute to these disparities. Evidence links patient-centered care to improvements in mental health outcomes; therefore, quality improvement interventions that enhance this dimension of care are promising strategies to improve treatment and outcomes of depression among African Americans. This paper describes the design of the BRIDGE (Blacks Receiving Interventions for Depression and Gaining Empowerment) Study. The goal of the study is to compare the effectiveness of two interventions for African-American patients with depression--a standard quality improvement program and a patient-centered quality improvement program. The main hypothesis is that patients in the patient-centered group will have a greater reduction in their depression symptoms, higher rates of depression remission, and greater improvements in mental health functioning at six, twelve, and eighteen months than patients in the standard group. The study also examines patient ratings of care and receipt of guideline-concordant treatment for depression.</p> <p>Methods/Design</p> <p>A total of 36 primary care clinicians and 132 of their African-American patients with major depressive disorder were recruited into a cluster randomized trial. The study uses intent-to-treat analyses to compare the effectiveness of standard quality improvement interventions (academic detailing about depression guidelines for clinicians and disease-oriented care management for their patients) and patient-centered quality improvement interventions (communication skills training to enhance participatory decision-making for clinicians and care management focused on explanatory models, socio-cultural barriers, and treatment preferences for their patients) for improving outcomes over 12 months of follow-up.</p> <p>Discussion</p> <p>The BRIDGE Study includes clinicians and African-American patients in under-resourced community-based practices who have not been well-represented in clinical trials to improve depression care. The patient-centered and culturally targeted approach to depression care is a relatively new one that has not been tested in most previous studies. The study will provide evidence about whether patient-centered accommodations improve quality of care and outcomes to a greater extent than standard quality improvement strategies for African Americans with depression.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov NCT00243425</p

Microstructural evolution and trace element mobility in Witwatersrand pyrite

Microstructural analysis of pyrite from a single sample of Witwatersrand conglomerate indicates a complex deformation history involving components of both plastic and brittle deformation. Internal deformation associated with dislocation creep is heterogeneously developed within grains, shows no systematic relationship to bulk rock strain or the location of grain boundaries and is interpreted to represent an episode of pyrite deformation that predates the incorporation of detrital pyrite grains into the Central Rand conglomerates. In contrast, brittle deformation, manifest by grain fragmentation that transects dislocation-related microstructures, is spatially related to grain contacts and is interpreted to represent post-depositional deformation of the Central Rand conglomerates. Analysis of the low-angle boundaries associated with the early dislocation creep phase of deformation indicates the operation of {100} slip systems. However, some orientation boundaries have geometrical characteristics that are not consistent with simple {100} deformation.These boundaries may represent the combination of multiple slip systems or the operation of the previously unrecognized {120} slip system. These boundaries are associated with order of magnitude enrichments in As, Ni and Co that indicate a deformation control on the remobilization of trace elements within pyrite and a potential slip system control on the effectiveness of fast-diffusion pathways. The results confirm the importance of grain-scale elemental remobilization within pyrite prior to their incorporation into the Witwatersrand gold-bearing conglomerates. Since the relationship between gold and pyrite is intimately related to the trace element geochemistry of pyrite, the results have implications for the application of minor element geochemistry to ore deposit formation, suggest a reason for heterogeneous conductivity and localized gold precipitation in natural pyrite and provide a framework for improving mineral processing

Two approaches to the study of the origin of life.

This paper compares two approaches that attempt to explain the origin of life, or biogenesis. The more established approach is one based on chemical principles, whereas a new, yet not widely known approach begins from a physical perspective. According to the first approach, life would have begun with - often organic - compounds. After having developed to a certain level of complexity and mutual dependence within a non-compartmentalised organic soup, they would have assembled into a functioning cell. In contrast, the second, physical type of approach has life developing within tiny compartments from the beginning. It emphasises the importance of redox reactions between inorganic elements and compounds found on two sides of a compartmental boundary. Without this boundary, ¿life¿ would not have begun, nor have been maintained; this boundary - and the complex cell membrane that evolved from it - forms the essence of life

Ultrafast laser micro-nano structuring of transparent materials with high aspect ratio

Ultrafast lasers are ideal tools to process transparent materials because they spatially confine the deposition of laser energy within the material's bulk via nonlinear photoionization processes. Nonlinear propagation and filamentation were initially regarded as deleterious effects. But in the last decade, they turned out to be benefits to control energy deposition over long distances. These effects create very high aspect ratio structures which have found a number of important applications, particularly for glass separation with non-ablative techniques. This chapter reviews the developments of in-volume ultrafast laser processing of transparent materials. We discuss the basic physics of the processes, characterization means, filamentation of Gaussian and Bessel beams and provide an overview of present applications

High-Anxious Individuals Show Increased Chronic Stress Burden, Decreased Protective Immunity, and Increased Cancer Progression in a Mouse Model of Squamous Cell Carcinoma

In spite of widespread anecdotal and scientific evidence much remains to be understood about the long-suspected connection between psychological factors and susceptibility to cancer. The skin is the most common site of cancer, accounting for nearly half of all cancers in the US, with approximately 2–3 million cases of non-melanoma cancers occurring each year worldwide. We hypothesized that a high-anxious, stress-prone behavioral phenotype would result in a higher chronic stress burden, lower protective-immunity, and increased progression of the immuno-responsive skin cancer, squamous cell carcinoma. SKH1 mice were phenotyped as high- or low-anxious at baseline, and subsequently exposed to ultraviolet-B light (1 minimal erythemal dose (MED), 3 times/week, 10-weeks). The significant strengths of this cancer model are that it uses a normal, immunocompetent, outbred strain, without surgery/injection of exogenous tumor cells/cell lines, and produces lesions that resemble human tumors. Tumors were counted weekly (primary outcome), and tissues collected during early and late phases of tumor development. Chemokine/cytokine gene-expression was quantified by PCR, tumor-infiltrating helper (Th), cytolytic (CTL), and regulatory (Treg) T cells by immunohistochemistry, lymph node T and B cells by flow cytometry, adrenal and plasma corticosterone and tissue vascular-endothelial-growth-factor (VEGF) by ELISA. High-anxious mice showed a higher tumor burden during all phases of tumor development. They also showed: higher corticosterone levels (indicating greater chronic stress burden), increased CCL22 expression and Treg infiltration (increased tumor-recruited immuno-suppression), lower CTACK/CCL27, IL-12, and IFN-γ gene-expression and lower numbers of tumor infiltrating Th and CTLs (suppressed protective immunity), and higher VEGF concentrations (increased tumor angiogenesis/invasion/metastasis). These results suggest that the deleterious effects of high trait anxiety could be: exacerbated by life-stressors, accentuated by the stress of cancer diagnosis/treatment, and mediate increased tumor progression and/or metastasis. Therefore, it may be beneficial to investigate the use of chemotherapy-compatible anxiolytic treatments immediately following cancer diagnosis, and during cancer treatment/survivorship

Protein quality control: the who’s who, the where’s and therapeutic escapes

In cells the quality of newly synthesized proteins is monitored in regard to proper folding and correct assembly in the early secretory pathway, the cytosol and the nucleoplasm. Proteins recognized as non-native in the ER will be removed and degraded by a process termed ERAD. ERAD of aberrant proteins is accompanied by various changes of cellular organelles and results in protein folding diseases. This review focuses on how the immunocytochemical labeling and electron microscopic analyses have helped to disclose the in situ subcellular distribution pattern of some of the key machinery proteins of the cellular protein quality control, the organelle changes due to the presence of misfolded proteins, and the efficiency of synthetic chaperones to rescue disease-causing trafficking defects of aberrant proteins