Contrast at very low energies of the gold/carbon specimen for resolution testing

This paper concerns the problem of testing the image resolution in scanned electron micrographs, namely from the point of view of the image contrast for the standard gold/carbon test specimen within the full energy scale, down to eV units. Microscopes equipped with a cathode lens are considered and experimental results are presented for three devices differing in vacuum conditions and fields surrounding the specimen. At very low energies, the contrast is shown to either invert or disappear and this ambiguity is discussed and confronted with data simulated on the basis of measured electron yields from gold and carbon. It is concluded that the observations can be explained in terms of the surface cleanliness and strength of the surrounding fields.     

Exploiting Memristive BiFeO3 Bilayer Structures for Compact Sequential Logics

Resistive switching devices are considered as one of the most promising candidates for the next generation memories and nonvolatile logic applications. In this paper, BiFeO₃:Ti/BiFeO₃ (BFTO/BFO) bilayer structures with optimized BFTO/BFO thickness ratio which show symmetric, bipolar, and nonvolatile resistive switching with good retention and endurance performance, are presented. The resistive switching mechanism is understood by a model of flexible top and bottom Schottky‐like barrier heights in the BFTO/BFO bilayer structures. The resistive switching at both positive and negative bias make it possible to use both polarities of reading bias to simultaneously program and store all 16 Boolean logic functions into a single cell of a BFTO/BFO bilayer structure in three logic cycles.     

Running versus weight lifting in the treatment of depression.

We compared the effectiveness of an aerobic and nonaerobic exercise in the treatment of clinical depression in women. A total of 40 women, screened on the Research Diagnostic Criteria for major or minor depressive disorder, were randomly assigned to an 8-week running (aerobic), weight-lifting (nonaerobic), or wait-list control condition. Subjects were reassessed at mid- and posttreatment, and at 1-, 7-, and 12-month follow-ups. Depression was monitored by the Beck Depression Inventory, Lubin's Depression Adjective Check List, and the Hamilton Rating Scale for Depression; fitness level was assessed using submaximal treadmill testing. Results were remarkably consistent across measures, with both exercise conditions significantly reducing depression compared with the wait list control condition, and generally appearing indistinguishable from each other. No significant between-group fitness changes were noted. These findings indicate that both types of exercise conditions significantly reduce depression and that these results are not dependent on achieving an aerobic effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cartilage replacement by use of hybrid systems of autologous cells and polyethylene: an experimental study

This study used porous polyethylene (PE) as a scaffold in an animal model system. The surface of the scaffolds was either modified with collagen II coating or first functionalized by oxygen plasma treatment and then coated with collagen II. The specimens were inoculated with autologous chondrocytes and transplanted into the concha of guinea pigs. Bare scaffolds were used as controls. Periods of 1, 6, and 12 months after implantation, samples of cells containing specimens and control samples were evaluated microscopically. As a result, the pre-seeded specimens were better integrated into the surrounding tissue than cell-free PE-specimens. Also a weaker immune reaction and an improved cartilage generation could be detected in the pre-seeded specimen. Compared to the other surface modifications, no further improvement of cartilage development was observed in the long term in vivo animal experimental study.     

UHPLC-ESI-MS/MS Quantification of Relevant Substrates and Metabolites of the Kynurenine Pathway Present in Serum and Peritoneal Fluid from Gastric Cancer Patients—Method Development and Validation

Metabolites and enzymes involved in the kynurenine pathway (KP) are highly promising targets for cancer treatment, including gastrointestinal tract diseases. Thus, accurate quantification of these compounds in body fluids becomes increasingly important. The aim of this study was the development and validation of the UHPLC-ESI-MS/MS methods for targeted quantification of biologically important KP substrates (tryptophan and nicotinamide) and metabolites(kynurenines) in samples of serum and peritoneal fluid from gastric cancer patients. The serum samples were simply pretreated with trichloroacetic acid to precipitate proteins. The peritoneal fluid was purified by solid-phase extraction before analysis. Validation was carried out for both matrices independently. Analysis of the samples from gastric cancer patients showed different accumulations of tryptophan and its metabolites in different biofluids of the same patient. The protocols will be used for the evaluation of tryptophan and kynurenines in blood and peritoneal fluid to determine correlation with the clinicopathological status of gastric cancer or the disease’s prognosis.     

Inhibition of influenza virus activity by multivalent glycoarchitectures with matched sizes

We describe the synthesis of a series of sialic acid‐conjugated, polyglycerol‐based nanoparticles with diameters in the range of 1–100 nm. Particle sizes were varied along with the degree of functionalization to match the corresponding virus size and receptor multiplicity in order to achieve maximum efficiency. To build up these architectures, we used biocompatible, hyperbranched polyglycerols as scaffolds and recently developed polyglycerol‐based nanogels, the sizes of which can be varied between 2–4 nm and 40–100 nm, respectively. We demonstrate here that such multivalent nanoparticles inhibit influenza A virus cell binding and fusion and consequently infectivity. The potential of multivalency is evident from larger particles showing very efficient inhibition of viral infection up to 80 %. Indeed, both the size of the nanoparticle and the amount of ligand density are important determinants of inhibition efficiency. The inhibitory activity of the tested polymeric nanoparticles drastically increased with size. Particles with similar dimensions to the virus (50–100 nm) are exceedingly effective. We also observed a saturation point in degree of surface functionalization (i.e. ligand density), above which inhibition was not significantly improved. Our study emphasizes the importance of matching particle sizes and ligand densities to mimic biological surfaces and improve interactions; this is a vital concept underlying multivalent interactions.     

Deposition of Silicon Carbide and Nitride‐Based Coatings by Atmospheric Plasma Spraying

In this work atmospheric plasma spraying of SiC and Si₃N₄ was investigated. Plasma spraying of these ceramics raises several problems since they would tend to decompose instead of melting at elevated temperatures during the process. To circumvent this problem the nonoxide ceramics were deposited as a composite powder mixed with nonoxide ceramic particles resulting in a ceramic/ceramic composite structure. Our findings were that using such a composite feedstock powder both oxidation and decomposition of the nonoxide particles could be avoided. A vitrified phase was also developed in the coating.     

Promising perspectives towards regrowing a human arm

Despite the great enthusiasm about tissue engineering during the 1980s and the many significant basic observations made since then, the clinical application of tissue-engineered products has been limited. However, the prospect of creating new human tissues and organs is still exciting and continues to be a significant challenge for scientists and clinicians. A human arm is an extremely complicated biological construction. Considering regrowing a human arm requires asking about the current state-of-the-art of tissue engineering and the real capabilities that it may offer within a realistic time horizon. This work briefly addresses the state-of-the-art in the fields of cells and scaffolds that have high regenerative potential. Additional tools that are required to reconstruct more complex parts of the body, such as a human arm, seem achievable with the already available more sophisticated culture systems including three-dimensional organization, dynamic conditions and co-cultures. Finally, we present results on cell differentiation and cell and tissue maturation in culture when cells are exposed to mechanical forces. We postulate that in the foreseeable future even such complicated structures such as a human arm will be regrown in full in vitro under the conditions of a mechanically controlled co-culture system.