Mapping the isoprenoid binding pocket of PDEdelta by a semisynthetic, photoactivatable N-Ras lipoprotein

Biologically functional Ras isoforms undergo post-translational modifications starting with farnesylation of the most C-terminal cysteine. Combined with further processing steps, this isoprenylation allows for the anchoring of these proteins in endomembranes, where signal transduction events take place. The specific localization is subject to dynamic regulation and assumed to modulate the activity of Ras proteins by governing their spatiotemporal distribution. The delta subunit of phosphodiesterase (PDEdelta) has attracted attention as a solubilization factor of isoprenylated Ras. In this study, we demonstrate that critical residues in the putative isoprenoid pocket of PDEdelta can be mapped by coupling with a semisynthetic N-Ras lipoprotein in which the native farnesyl group of the processed protein was replaced by a photoactivatable geranyl benzophenone moiety. The crosslinked product included parts of beta-sheet 9 of PDEdelta, which contains the highly conserved amino acids V145 and L147. Modeling of the PDEdelta-geranyl benzophenone (GerBP) complex supports the conclusion that the photolabeled sequence is embedded in the putative isoprenoid pocket of PDEdelta.     

Nido-Hydroborate-Based Electrolytes for All-Solid-State Lithium Batteries

Hydroborate-based solid electrolytes have recently been successfully employed in high voltage, room temperature all-solid-state sodium batteries. The transfer to analogous lithium systems has failed up to now due to the lower conductivity of the corresponding lithium compounds and their high cost. Here LiB₁₁H₁₄ nido-hydroborate as a cost-effective building block and its high-purity synthesis is introduced. The crystal structures of anhydrous LiB₁₁H₁₄ as well as of LiB₁₁H₁₄-based mixed-anion solid electrolytes are solved and high ionic conductivities of 1.1 × 10⁻⁴ S cm⁻¹ for Li₂(B₁₁H₁₄)(CB₁₁H₁₂) and 1.1 × 10⁻³ S cm⁻¹ for Li₃(B₁₁H₁₄)(CB₉H₁₀)₂ are obtained, respectively. LiB₁₁H₁₄ exhibits an oxidative stability limit of 2.6 V versus Li⁺/Li and the proposed decomposition products are discussed based on density functional theory calculations. Strategies are discussed to improve the stability of these compounds by modifying the chemical structure of the nido-hydroborate cage. Galvanostatic cycling in symmetric cells with two lithium metal electrodes shows a small overpotential increase from 22.5 to 30 mV after 620 h (up to 0.5 mAh cm⁻²), demonstrating that the electrolyte is compatible with metallic anodes. Finally, the Li₂(B₁₁H₁₄)(CB₁₁H₁₂)  electrolyte is employed in a proof-of-concept half cell with a TiS₂ cathode with a capacity retention of 82% after 150 cycles at C/5.     

Inhomogeneity of CoCrW powder products manufactured by SLM technology

Journal of Mechanical Science and Technology - The article deals with selective laser melting process using CoCrW powder. Our aim was to identify the influence of product position on the building...     

The involvement of oxidative stress in ochratoxin A and fumonisin B1 toxicity in rats

The aim of this study was to find out whether very low doses of nephrotoxic and hepatotoxic mycotoxins ochratoxin A (OTA) and fumonisin B1 (FB1) induce oxidative stress in rat kidney and liver and whether their effect is synergistic. Rats were treated orally with OTA (5 ng/kg b.w. and 50 microg/kg b.w.) and FB1 (200 ng/kg b.w. and 50 microg/kg b.w.), or their combinations. Malondialdehyde (MDA) and protein carbonyls (PCs) concentration in kidney was affected with lower dose of OTA than in liver (p<0.05). FB1 did not affect MDA and PCs concentrations in the liver, while in the kidney both FB1 doses increased MDA concentration (p<0.05). The combination of the lower doses of OTA+FB1 increased the MDA and PCs concentration both in the liver and the kidney, compared to controls and animals treated with respective doses of mycotoxins (p<0.05). The combinations of mycotoxins reduced the catalase activity only in the kidney when compared to controls (p<0.05). In contrast to the increased kidney concentrations of MDA and PCs even with very low doses of OTA and FB1, the activity of catalase and SOD does not change. Combinations of OTA+FB1 affected almost all parameters, which indicates their potential to produce oxidative damage.     

Single-channel blind estimation of arterial input function and tissue impulse response in DCE-MRI

Multipass dynamic MRI and pharmacokinetic modeling are used to estimate perfusion parameters of leaky capillaries. Curve fitting and nonblind deconvolution are the established methods to derive the perfusion estimates from the observed arterial input function (AIF) and tissue tracer concentration function. These nonblind methods are sensitive to errors in the AIF, measured in some nearby artery or estimated by multichannel blind deconvolution. Here, a single-channel blind deconvolution algorithm is presented, which only uses a single tissue tracer concentration function to estimate the corresponding AIF and tissue impulse response function. That way, many errors affecting these functions are reduced. The validity of the algorithm is supported by simulations and tests on real data from mouse. The corresponding nonblind and multichannel methods are also presented.     

离子表面活性剂和胶原间的相互作用

研究了二十烷基苯磺酸钠（SDBS）和溴化十六烷基吡啶翁（CPB）表面活性剂同胶原纤维（BAT）的反应。在酸性环境（pH＝3）和等电点条件（CrBATpH=6.5,SBAT PH=4)决定了吸附作用等温线。同时，研究了底物的膨胀变化（用αm表示膨胀度）。已经证实了离子表面活性剂对铬鞣和植物鞣胶原的吸收。发现SDBS对CrBAT的吸收与反应的pH值无关而取决于铬进一步吸收的活性位置的含量。在酸性区域，结合SDBS不使CrBAT纤维膨胀，而CrBAT在等电点条件下存在较轻微的膨胀。CPB与CrBAT的结合量较小，在同样的反应条件下，CPB在pH=6.5时的吸收实际与其对未鞣 的BAT的吸收相同。靠SBAT在高pH值下的稳定性，离子表面活性剂对SBAT的吸收要在pH=4时有效。预测SBDS的吸收更低，但等温线是S形相对于c.m.c.SDBS有一个滞后的段。CPB－SBAT和SDBS－BAT反应，当CPB对BAT吸收时纤维会发生轻微的膨胀。     

Accelerated High Speed Water Erosion Test for Concrete Wear Debris Analysis

This paper contains investigations of wear particles generated during the erosive wear of four different concrete, mixtures by high velocity water flow at velocities of about 700 m/s.ⁱ The wear particles were collected, dried and analyzed by sieve experiments. Based on the sieve analysis, specific surface and average grain diameter of the particle samples were estimated. 'Using simple, comminution relations, the specific crack length of every' sample is calculated. It is shown that all estimated parameters exhibit a strong relationship to characteristic material properties, such as compressive strength, Young's modulus, and absorbed fracture energy. It was found by regression analysis that the average debris wear size can be effectively characterized by the absorbed fracture energy of the concrete sample. It is concluded that these relations are the result of different paths of fracture propagation through the materials during the generation of a microcrack network.     

Numerical modeling and experimental study of thermally induced residual stress in the direct diode laser heat treatment of dual-phase 980 steel

The direct diode laser application has been found useful in the localized heat treatment of metal parts because of its wider beam and more uniform energy distribution with respect to other lasers with Gaussian-like energy distribution. In this study, an uncoupled thermomechanical finite element model is developed to study the temperature field and thermally induced stress evolution in high-strength dual phase (DP) 980 steel during its direct diode laser heat treatment. Thermal analysis results are experimentally validated through thermocouples and then input into a mechanical model as transient temperature loading in order to acquire the thermally induced stresses and strains. The effect of martensite phase transformation on residual stress distribution in heat-treated DP980 steel is considered. An X-ray diffraction technique is used to measure the residual stress distribution at the top surface of the heat-treated coupons of DP980 steel. The numerical results show that compressive stresses are located at the laser–material interaction zone. After heat treatment, tensile stresses are retained at the heat-treated DP980 steel coupons. There is qualitative agreement between the numerically predicted and experimentally measured residual stresses. The effect of the overlapping ratio on the residual stress and hardness of the heat-treated DP980 steel is also experimentally and numerically investigated.     

The design and production of Ti-6Al-4V ELI customized dental implants

This paper addresses the production of customized Ti-6Al-4V ELI dental implants via electron beam melting (EBM). The melting of Ti-6Al-4V ELI powder produces implants with great biocompatibility, fi ne mechanical performance, and a high bone ingrowth potential. The EBM technology is used to produce one-component dental implants that mimic the exact shape of the patient’s tooth, replacing the traditional, three-component, “screw-like” standardized dental implants currently used. The new generation of implants provides the possibility of simplifying pre-insertion procedures leading to faster healing time, and the potential of better and stronger osseointegration, specifi cally through incorporating lattice structure design.