Alpha-cyano-4-hydroxycinnamic acid affinity sample preparation. A protocol for MALDI-MS peptide analysis in proteomics

We present a new MALD1 sample preparation technique for peptide analysis using the matrix alpha-cyano-4-hydroxy-cinnamic acid (CHCA) and prestructured sample supports. The preparation integrates sample purification, based on the affinity of microcrystalline CHCA for peptides, thereby simplifying the analysis of crude peptide mixtures. Enzymatic digests can thus be prepared directly, without preceding purification. Prepared samples are homogeneous, facilitating automatic spectra acquisition. This method allows preparation of large numbers of samples with little effort and without the need for automation. These features make the described preparation suitable for cost-efficient high-throughput protein identification. Performance of the sample preparation is demonstrated with in situ proteolytic digests of human brain proteins separated by two-dimensional gel electrophoresis.     

Tailoring the crystal structure of individual silicon nanowires by polarized laser annealing

We study the effect of polarized laser annealing on the crystalline structure of individual crystalline-amorphous core-shell silicon nanowires (NWs) using Raman spectroscopy. The crystalline fraction of the annealed spot increases dramatically from 0 to 0.93 with increasing incident laser power. We observe Raman lineshape narrowing and frequency hardening upon laser annealing due to the growth of the crystalline core, which is confirmed by high resolution transmission electron microscopy (HRTEM). The anti-Stokes:Stokes Raman intensity ratio is used to determine the local heating temperature caused by the intense focused laser, which exhibits a strong polarization dependence in Si NWs. The most efficient annealing occurs when the laser polarization is aligned along the axis of the NWs, which results in an amorphous-crystalline interface less than 0.5 μm in length. This paper demonstrates a new approach to control the crystal structure of NWs on the sub-micron length scale.     

Nano structured physical vapor deposited coatings by means of picosecond laser radiation

Molding of nano structures by injection molding leads to special requirements for the tools e.g., wear resistance and as low as possible release forces of the molded components. On the other hand it is not allowed to affect the replication precision. Physical vapor deposition is one of the promising technologies for applying coatings with adapted properties like high hardness, low roughness, low Young's modulus and less adhesion to the plastics melt. Although physical vapor deposition technology allows the deposition of films on micro structures without changing the structure significantly, film deposition on nano structures and small micro structures leads to a relevant change in surface topography. For this reason direct structuring of physical vapor deposition coatings might be beneficial. In this paper structuring was done using a picoseconds ultraviolet laser, Lumera Laser "Rapid," with a master oscillator power amplifier system at 355 nm. Two different coatings were deposited by magnetron sputter ion plating physical vapor deposition technology for laser structuring tests ((Cr, Al)N, (Cr, Al,Si)N). After deposition, the coatings were analyzed by common techniques regarding hardness, Young's modulus and morphology. The structures were analyzed by scanning electron microscopy. The results show a high potential for laser structuring of coatings deposited via physical vapor deposition. Linear structures with sizes between 400 nm and 10microm were realized.     

Hydrogen content variation for enhancing the lubricated tribological performance of DLC coatings with ester

There are many types of DLC (diamond-like carbon) coatings, which mainly differ from each other according to their hydrogen content, sp² and sp³-bonded carbon atoms and alloying elements (such as Ti, Cr, W or Zr). The lubricated tribological performance of these coatings depends on the lubricant. Controversially, the same lubricant delivers different tribological performances with differently produced DLC coatings. It has been observed that the presence of hydrogen has a remarkable effect on the tribological performance of DLC coatings in inert and vacuum environments. In this paper, the hydrogen content of two different types of DLC coatings, a-C:H:Me (metal containing hydrogenated amorphous carbon) and a-C:H, was varied, in order to obtain an optimized tribological behavior with a synthetic ester (TMP ester). The tribological performance of the coatings with TMP ester is examined in a pin-on-disk tribometer. It could be shown that increasing the hydrogen content in a DLC coating improves their tribological performance with TMP ester. Besides, a-C:H type of coatings is found to be more suitable for TMP ester regarding low friction coefficients.     

Filled temperature‐sensitive poly(vinyl methyl ether) hydrogels

Temperature‐sensitive hydrogels based on poly(vinyl methyl ether) (PVME) with ferroelectric or ferromagnetic properties were synthesized by high‐energy irradiation. Barium titanate and poly(vinylidene fluoride) (PVDF) were used as ferroelectric filler and Ni as ferromagnetic filler. The filled PVME hydrogels were synthesized by electron beam or γ‐ray irradiation (of a suspension with 5–50 wt % of filler (with respect to polymer mass) in a 20 wt % aqueous PVME solution). Filling of the gel reduces the absolute swelling degree at low temperatures, but do not influence the phase‐transition temperature of the gel. The particle distribution of the fillers inside the gel was visualized by field emission scanning electron microscopy. The fillers were incorporated in the PVME network and fixed because of their size (inorganic particles), as well as by chemical bonds (PVDF). The ferroelectric or ferromagnetic properties of the filled gels were proved. Measurements in a corresponding alternating field provide the hysteresis loop, for both the ferromagnetic and ferroelectric gel. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2253–2265, 2005     

A Relational Turbulence Model of Military Service Members' Relational Communication During Reintegration

This study employed the relational turbulence model to examine features of relational communication and dimensions of relational inferences during the postdeployment transition for military service members. We surveyed 220 military personnel who had recently returned home from deployment about their romantic relationship. Results of a structural equation model indicated that relational uncertainty and interference from partners predicted openness and aggressiveness, which in turn predicted appraisals of affiliation and dominance in the relationship. The results imply that the transition from deployment to reunion corresponds with upheaval in how service members communicate with a romantic partner and make judgments about their relationship.     

ImmunoFET feasibility in physiological salt environments

Field-effect transistors (FETs) are solid-state electrical devices featuring current sources, current drains and semiconductor channels through which charge carriers migrate. FETs can be inexpensive, detect analyte without label, exhibit exponential responses to surface potential changes mediated by analyte binding, require limited sample preparation and operate in real time. ImmunoFETs for protein sensing deploy bioaffinity elements on their channels (antibodies), analyte binding to which modulates immunoFET electrical properties. Historically, immunoFETs were assessed infeasible owing to ion shielding in physiological environments. We demonstrate reliable immunoFET sensing of chemokines by relatively ion-impermeable III-nitride immunoHFETs (heterojunction FETs) in physiological buffers. Data show that the specificity of detection follows the specificity of the antibodies used as receptors, allowing us to discriminate between individual highly related protein species (human and murine CXCL9) as well as mixed samples of analytes (native and biotinylated CXCL9). These capabilities demonstrate that immunoHFETs can be feasible, contrary to classical FET-sensing assessment. FET protein sensors may lead to point-of-care diagnostics that are faster and cheaper than immunoassay in clinical, biotechnological and environmental applications.     

Experimental Investigation of a Novel Circuit for Millimeter-Wave TWTs

A novel folded waveguide circuit that features thick iron pole pieces with hollow centers was built as part of a periodic-permanent-magnet-focused W-band single-stage test-vehicle traveling-wave tube (TWT). These hollow centers, which comprise part of the slow wave circuit, increase the rms axial field and significantly reduce the unwanted transverse field imbalance. For this TWT, a tetrode gun that creates an ultralaminar 20-kV 0.25-A nominal electron beam was used. It was demonstrated that this gun and magnetic structure can provide greater than 97% beam transmission for peak beam power levels as high as 9.25 kW (25 kV, 0.37 A). The unplated circuit, operating around 91 GHz on the edge of a passband, exhibits between 10 dB and 12 dB gain that compares favorably with results of device modeling utilizing the 3D particle-in-cell code Magic3D. Using a feedback approach to characterize large-signal operation, the tube generated 40 W of regenerative oscillator power. Design-optimized versions of this circuit show promise of enabling W-band TWT amplifiers that provide up to 300 W of peak RF output power     

Depressive symptoms and mechanisms of relational turbulence as predictors of relationship satisfaction among returning service members.

In contrast to romanticized portrayals of reunion after deployment, U.S. military personnel may contend with the harsh reality of both depressive symptoms and upheaval in their romantic relationships during the postdeployment transition. This study employed the relational turbulence model to evaluate mechanisms linking depressive symptoms with relationship satisfaction. Cross-sectional, self-report data were collected from 220 service members living in 27 states who had returned home from deployment within the past six months. As hypothesized, the negative association between depressive symptoms and relationship satisfaction was mediated by relational uncertainty and interference from partners. These findings advance scholarship on depressive symptoms and relational turbulence, and they also suggest guidelines for helping service members with depressive symptoms maintain satisfying romantic relationships upon reentry. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Cytotoxicity study of tacrine, structurally and pharmacologically related compounds using rat hepatocytes

Tacrine is the first drug approved for the treatment of Alzheimer's disease. Approximately 50% of patients treated with tacrine develop elevated serum aminotransferase levels, as an indication of potential hepatotoxicity. However, acute and chronic studies with a limited number of animal models have not demonstrated hepatotoxicity. The present study compared the cytotoxicity in hepatocyte cultures of tacrine with structurally (proflavine and 9-aminoacridine) or pharmacologically similar compounds (physostigmine), as well as structurally modified tacrine to determine if there was a structure activity relationship with regards to toxicity. Cytotoxicity was assessed by determination of extra- and intracellular amounts of lactate dehydrogenase. Cytotoxicity was assessed after a four-hour exposure over a test compound concentration range of 0 to 3 mM. Concentration-dependent cytotoxicity occurred with tacrine and all structurally related compounds. Physostigmine which is pharmacologically similar, but structurally different, did not induce cytotoxicity. Cytotoxic potency did not appear to be related to acetylcholinesterase inhibitory activity, while compounds with acridine structures induced cytotoxicity. Thus, in this in vitro model, cytotoxicity appears to be related to structure and not pharmacological action. Results of this study indicate that compounds structurally related to tacrine are cytotoxic because of the heterocyclic ring structure. Neither unsaturation of an aromatic ring of the heterocyclic compound, amino substitution of the heterocyclic rings, N-hydroxylation of the amino group, nor ring hydroxylation dramatically alter cytotoxicity.