The chemoselective one-step alkylation and isolation of thiophosphorylated cdk2 substrates in the presence of native cysteine

The elucidation of signalling pathways relies heavily upon the identification of protein kinase substrates. Recent investigations have demonstrated the efficacy of chemical genetics using ATP analogues and modified protein kinases for specific substrate labelling. Here we combine N(6) -(cyclohexyl)ATPγS with an analogue-sensitive cdk2 variant to thiophosphorylate its substrates and demonstrate a pH-dependent, chemoselective, one-step alkylation to facilitate the detection or isolation of thiophosphorylated peptides.     

Preparation and properties of swellable thermoplastic elastomer alloys based on elastomeric powder,polypropylene, and superabsorbent polymer

This paper focuses on the development of swellable thermoplastic elastomer alloys based on elastomeric powder, polypropylene, and superabsorbent polymer. The mechanical and swelling properties of the resulting materials were investigated at varying concentrations of the components and by compatiblization between the rubber particles of the elastomeric powder and the polypropylene phase using the peroxide 2,5‐dimethyl‐2,5di(t‐buthylperoxy)hexane as compatibilizer. The materials obtained could be processed by injection molding in the same way as thermoplastics. The mechanical and swelling properties of the materials could be controlled by shifting the concentrations of the components. The swelling properties in different swelling media were investigated. A maximum of 120% of the relative increase of mass was obtained using KOH solution. The positions of the SAP particles within the material were detected by a combined method of SEM and EDX scan. Elastomeric powder and thermoplastic build the matrix material, in which the SAP particles are embedded mechanically. A schematic illustration of the material structure was developed, and the liquid was suspected to be transported by diffusion into the material matrix as well as along the interface between SAP and the matrix material. The results obtained can be used for the design of improved sealing concepts, as they evidence a good method of using recycled elastomers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Testing non‐parametric hypotheses for stationary processes by estimating minimal distances

In this article, new tests for non‐parametric hypotheses in stationary processes are proposed. Our approach is based on an estimate of the L²‐distance between the spectral density matrix and its best approximation under the null hypothesis. We explain the main idea in the problem of testing for a constant spectral density matrix and in the problem of comparing the spectral densities of several correlated stationary time series. The method is based on direct estimation of integrals of the spectral density matrix and does not require the specification of smoothing parameters. We show that the limit distribution of the proposed test statistic is normal and investigate the finite sample properties of the resulting tests by means of a small simulation study.     

Contention-based forwarding for mobile ad hoc networks

Existing position-based unicast routing algorithms which forward packets in the geographic direction of the destination require that the forwarding node knows the positions of all neighbors in its transmission range. This information on direct neighbors is gained by observing beacon messages each node sends out periodically.

Due to mobility, the information that a node receives about its neighbors becomes outdated, leading either to a significant decrease in the packet delivery rate or to a steep increase in load on the wireless channel as node mobility increases. In this paper, we propose a mechanism to perform position-based unicast forwarding without the help of beacons. In our contention-based forwarding scheme (CBF) the next hop is selected through a distributed contention process based on the actual positions of all current neighbors. For the contention process, CBF makes use of biased timers. To avoid packet duplication, the first node that is selected suppresses the selection of further nodes. We propose three suppression strategies which vary with respect to forwarding efficiency and suppression characteristics. We analyze the behavior of CBF with all three suppression strategies and compare it to an existing greedy position-based routing approach by means of simulation with ns-2. Our results show that CBF significantly reduces the load on the wireless channel required to achieve a specific delivery rate compared to the load a beacon-based greedy forwarding strategy generates.     

Pentacene-based nanorods on Au(111) single crystals: Charge transfer, diffusion, and step-edge barriers

We investigate nanorod assemblies of two δ ₄-substituted pentacenes, namely (2,3-X ₂-9,10-Y ₂)-substituted pentacenes with X = Y = OCH₃ (MOP) and with X = F, Y = OCH₃ (MOPF), grown on Au(111) single crystals. By using a multi-technique approach based on ultraviolet photoelectron spectroscopy, X-ray photoelectron spectroscopy, and X-ray absorption, we find evidence for charge transfer screening at the interface with gold. Furthermore, the MOP and MOPF nanorods show a rough surface morphology, which was investigated with atomic force microscopy. We use molecular simulation techniques to investigate the energetic barriers to diffusion and to traverse step-edges to estimate their influence on the nanorod roughness. We find that barriers to surface diffusion on a terrace are anisotropic and that their direction favors the formation of nanorods in these materials.      

In vivo examination of the local inflammatory response after implantation of Ti6Al4V samples with a combined low-temperature plasma treatment using pulsed magnetron sputtering of copper and plasma-polymerized ethylenediamine

Copper (Cu) could serve as antibacterial coating for Ti6Al4V implants. An additional cell-adhesive layer might compensate Cu cytotoxicity. This study aimed at in vitro and in vivo evaluation of low-temperature plasma treatment of Ti6Al4V plates with Ti/Cu magnetron sputtering (Ti6Al4V–Ti/Cu), plasma-polymerized ethylenediamine (Ti6Al4V–PPEDA), or both (Ti6Al4V–Ti/Cu–PPEDA). Ti6Al4V–Ti/Cu and Ti6Al4V–Ti/Cu–PPEDA had comparable in vitro Cu release and antibacterial effectiveness. Following intramuscular implantation of Ti6Al4V–Ti/Cu, Ti6Al4V–PPEDA, Ti6Al4V–Ti/Cu–PPEDA and Ti6Al4V controls for 7, 14 and 56 days with 8 rats/day, peri-implant tissue was immunohistochemically examined for different inflammatory cells. Ti6Al4V–PPEDA had more mast cells and NK cells than Ti6Al4V, and more tissue macrophages, T lymphocytes, mast cells and NK cells than Ti6Al4V–Ti/Cu–PPEDA. Ti6Al4V–Ti/Cu had more mast cells than Ti6Al4V and Ti6Al4V–Ti/Cu–PPEDA. Results indicate that PPEDA-mediated cell adhesion counteracted Cu cytotoxicity. Ti6Al4V–Ti/Cu–PPEDA differed from Ti6Al4V only for mast cells on day 56. Altogether, implants with both plasma treatments had antibacterial properties and did not increase inflammatory reactions.     

Objectives in developing the European pressurized water reactor (EPR)

In 1991, major German utilities and Electricité de France agreed to develop, together with Siemens and Framatome, the nuclear island for the next generation of nuclear power plants. This nuclear island design is based on German and French experience in the construction and operation of pressurized water reactors. The major step in the evolutionary European pressurized water reactor (EPR) design is the systematic inclusion of events beyond classic design events. The mitigation of core melt accidents by special means, such as reinforcement of the containment function, primary loop depressurization, hydrogen reduction and ultimate heat removal, is part of the design, in addition to a number of features which increase the reliability of plant operation and accident control. Nevertheless, utilities and designers are aware of the economic challenge facing the EPR by the need to compete with other nuclear power plant designs and fossil plants for electricity generation.     

Nonlinear vector error tolerant interpolation of intermediate video images by weighted medians

The conversion of one video standard into another with different field and scan rates is a key feature for modern TV receivers and multimedia video equipment. Therefore, a new vector-based nonlinear conversion algorithm has been developed which applies nonlinear center weighted median (CWM) filters and yields a very good interpolation quality. One of the main properties of this algorithm is vector error tolerance. This property will be derived in this paper and its advantages will be shown. Assuming a 2-channel model of the human visual system with different spatio-temporal characteristics, there are contrary demands for the CWM filters. One can meet these demands by a vertical band separation and an application of the so-called temporally and spatially dominated CWMs. Hereby interpolation errors of the separated channels can be compensated by an adequate splitting of the spectrum. By this means, a very robust vector error tolerant upconversion method can be achieved which significantly improves the interpolation quality. By an appropriate choice of the CWM filter root structures main picture elements are interpolated correctly also if faulty vector fields occur. To demonstrate the correctness of the deduced interpolation scheme picture content is classified. These classes are distinguished by correct or incorrect vector assignment and correlated or noncorrelated picture content. The mode of operation of the new algorithm is portrayed for each class. Whereas for correlated picture content the mode of operation can be shown by object models the operation mode is shown for noncorrelated picture content by the output probability distribution function of the applied CWM filters. The new algorithm has been verified for a 100 Hz upconversion by objective evaluation methods and by comprehensive subjective test series. Within these tests for critical test sequences a gain of about 2 dB PSNR in the objective tests and about 0.4 evaluation grades in the subjective test series could be achieved.