Switching the conductance of Dy nanocontacts by magnetostriction

The electrical conductance G of mechanical break-junctions fabricated from the rare-earth metal dysprosium has been investigated at 4.2 K where Dy is in the ferromagnetic state. In addition to the usual variation of the conductance while breaking the wire mechanically, the conductance can be changed reproducibly by variation of the magnetic field H, due to the large magnetostriction of Dy. For a number of contacts, we observe discrete changes in G(H) in the range of several G(0) = 2e(2)/h. The behavior of G(H) and its angular dependence can be quantitatively understood by taking into account the magnetostrictive properties of Dy. This realization of a magnetostrictive few-atom switch demonstrates the possibility of reproducibly tuning the conductance of magnetic nanocontacts by a magnetic field.     

Dark roast coffee is more effective than light roast coffee in reducing body weight, and in restoring red blood cell vitamin E and glutathione concentrations in healthy volunteers

Recent results from prospective cohort studies have shown that moderate coffee consumption is associated with a reduced risk for diabetes mellitus type II or Alzheimer's disease. Since reactive oxygen species (ROS) are believed to be involved in the pathogenesis of these diseases, antioxidants in coffee might contribute to this risk reduction. We aimed at elucidating whether a dark roast coffee beverage (CB) rich in N‐methylpyridinium ions (NMP: 785 μmol/L) and low in chlorogenic acids (CGA: 523 μmol/L) has stronger antioxidant effects on human erythrocytes than a CB prepared from a light roast with opposite proportions (CGA: 4538 μmol/L; NMP: 56 μmol/L). Following a 2‐wk wash out period, 500 mL of the respective CB was administered to 30 subjects daily for 4‐wk. Blood and spot urine samples were collected at the beginning and at the end of each intervention. Intake of the dark roast CB most effectively improved the antioxidant status of erythrocytes: superoxide dismutase and glutathione peroxidase activity decreased by 5.8 and 15%, respectively, whereas tocopherol and total glutathione concentrations increased by 41 and 14%, respectively. Furthermore, administration of the NMP‐rich CB led to a significant body weight reduction in pre‐obese subjects, whereas the CGA‐rich CB did not.     

Preparation of monolayers of [MnIII6CrIII]3+ single-molecule magnets on HOPG,mica and silicon surfaces and characterization by means of non-contact AFM

We report on the characterization of various salts of [Mn^III₆Cr^III]³⁺ complexes prepared on substrates such as highly oriented pyrolytic graphite (HOPG), mica, SiO₂, and Si₃N₄. [Mn^III₆Cr^III]³⁺ is a single-molecule magnet, i.e., a superparamagnetic molecule, with a blocking temperature around 2 K. The three positive charges of [Mn^III₆Cr^III]³⁺ were electrically neutralized by use of various anions such as tetraphenylborate (BPh₄^-), lactate (C₃H₅O₃^-), or perchlorate (ClO₄^-). The molecule was prepared on the substrates out of solution using the droplet technique. The main subject of investigation was how the anions and substrates influence the emerging surface topology during and after the preparation. Regarding HOPG and SiO₂, flat island-like and hemispheric-shaped structures were created. We observed a strong correlation between the electronic properties of the substrate and the analyzed structures, especially in the case of mica where we observed a gradient in the analyzed structures across the surface.     

Developing and evaluating strategies to increase the material utilisation rate of hardwoods: a hybrid policy Delphi-SWOT analysis

European Journal of Wood and Wood Products - The indigenous hardwoods in German forests have a substantial ability to store carbon, and forestry reconstruction measures are anticipated to result in...     

Using a sparse promoting method in linear programming approximations to schedule parallel jobs

In this paper, we tackle the well‐known problem of scheduling a collection of parallel jobs on a set of processors either in a cluster or in a multiprocessor computer. For the makespan objective, that is, the completion time of the last job, this problem has been shown to be NP‐hard, and several heuristics have already been proposed to minimize the execution time. In this paper, we consider both rigid and moldable jobs. Our main contribution is the introduction of a new approach to the scheduling problem, based on the recent discoveries in the field of compressed sensing. In the proposed approach, all possible positions and shapes of the jobs are encoded into a matrix, and the scheduling is performed by selecting the best columns under natural constraints. Thus, the solution to the new scheduling formulation is naturally sparse, and we may use appropriate relaxations to achieve the optimization task in the quickest possible way. Among many possible relaxation strategies, we choose to minimize the ℓ_p‐quasi‐norm for p∈(0,1). Minimization of the ℓ_p‐quasi‐norm is implemented via a successive linear programming approximation heuristic. We propose several new algorithms based on this approach, and we assess their efficiency through simulations. The experiments show that the scheme outperforms the classic Largest Task First list based algorithm for scheduling small to medium instances but needs improvements to compete on larger numbers of jobs. Copyright © 2014 John Wiley & Sons, Ltd.     

Two-dimensional coordination polymer with tellurium nodes

Bis(diphenylphosphino)hexane disulfide and TeCl₄ afforded layered network coordination polymer with Te(II) nodes. The two-dimensional nets are positively charged, the anions and form layers alternating the polymeric networks.     

Ultrathin Polymeric Coatings Based on Hydrogen‐Bonded Polyphenol for Protection of Pancreatic Islet Cells

Though transplantation of pancreatic islet cells has emerged as a promising treatment for Type 1 diabetes its clinical application remains limited due to a number of limitations including both pathogenic innate and adaptive immune responses. This paper reports on a novel type of multifunctional cytoprotective material applied to coat living pancreatic islets. The coating utilizes hydrogen‐bonded interactions of a natural polyphenol (tannic acid) with poly(N‐vinylpyrrolidone) deposited on the islet surface via non‐ionic layer‐by‐layer assembly. It is demonstrated that the coating is conformal over the surface of mammalian islets including those derived from rat, non‐human primate (NHP), and human. In contrast to unmodified controls, the coated islets maintain their viability and β‐cell functionality for at least 96 hours in vitro. It is also determined that the coating demonstrates immunomodulatory cytoprotective properties suppressing pro‐inflammatory cytokine synthesis in stimulated bone marrow‐derived macrophages and diabetogenic BDC‐2.5 T cells. The coating material combines high chemical stability under physiologically relevant conditions with capability of suppressing cytokine synthesis, crucial parameters for prolonged islet integrity, viability, and function in vivo. This study offers new opportunities in the area of advanced multifunctional materials to be used for a cell‐based transplantation therapy     

Capillary isoelectric focusing and fluorometric detection of proteins and microorganisms dynamically modified by poly(ethylene glycol) pyrenebutanoate

The nonionogenic pyrene-based tenside, poly(ethylene glycol) pyrenebutanoate, was prepared and applied in capillary isoelectric focusing with fluorometric detection. This dye was used here as a buffer additive in capillary isoelectric focusing for a dynamic modification of the sample of proteins and microorganisms. The values of the isoelectric points of the labeled bioanalytes were calculated with use of the fluorescent pI markers and were found comparable with pI of the native compounds. The mixed cultures of proteins and microorganisms, Escherichia coli CCM 3954, Staphylococcus epidermidis CCM 4418, Proteus vulgaris, Enterococcus faecalis CCM 4224, and Stenotrophomonas maltophilia, the strains of the yeast cells, Candida albicans CCM 8180, Candida krusei, Candida parapsilosis, Candida glabrata, Candida tropicalis, and Saccharomyces cerevisiae were reproducibly focused and separated by the suggested technique. Using UV excitation for the on-column fluorometric detection, the minimum detectable amount was down to 10 cells injected on the separation capillary.