Effect of Processing Temperature on the Texture and Shear Mechanical Properties of Diffusion Bonded Ti-6Al-4V Multilayer Laminates

Two multilayer materials based on Ti-6Al-4V alloy have been processed by diffusion bonding at two different temperatures [1023 K and 1173 K (750 °C and 900 °C)]. The influence of the processing temperature on microstructure, texture, and mechanical properties of the two multilayer materials has been analyzed. Scanning electron microscopy, X-ray diffraction, electron backscatter diffraction, and shear tests have been used as experimental techniques. The multilayer laminate processed at the lowest temperature of 1023 K (750 °C) exhibits mainly transversal texture in the longitudinal plane, which provides an anisotropic mechanical behavior, showing higher shear modulus and maximum shear strength under one of the shear test directions considered. In contrast, diffusion bonding at 1173 K (900 °C) leads to basal/transversal texture because of the partial α → β → α transformation, which provides more isotropic mechanical properties. Accordingly, this laminate shows similar shear modulus and maximum shear strength in different shear test orientations.     

Inhibition of AKT-Signaling Sensitizes Soft Tissue Sarcomas (STS) and Gastrointestinal Stromal Tumors (GIST) to Doxorubicin via Targeting of Homology-Mediated DNA Repair

Activation of the phosphoinositide 3-kinase (PI3K)/Akt/mTOR pathway is well documented for a broad spectrum of human malignancies supporting their growth and progression. Accumulating evidence has also implicated AKT as a potent modulator of anti-cancer therapies via regulation of DNA damage response and repair (DDR) induced by certain chemotherapeutic agents and ionizing radiation (IR). In the present study, we examined the role of AKT signaling in regulating of Rad51 turnover and cytotoxic effects of topoisomerase II inhibitor, doxorubicin (Dox) in soft tissue sarcomas (STS) and gastrointestinal stromal tumors (GIST) in vitro. Blocking of AKT signaling (MK-2206) enhanced cytotoxic and pro-apoptotic effects of Dox in vast majority of STS and GIST cell lines. The phosphorylated form of Akt co-immunoprecipitates with Rad51 after Dox-induced DNA damage, whereas Akt inhibition interrupts this interaction and decreases Rad51 protein level by enhancing protein instability via proteasome-dependent degradation. Inhibition of Akt signaling in Dox-treated cells was associated with the increased number of γ-H2AX-positive cells, decrease of Rad51 foci formation and its colocalization with γ-H2AX foci, thereby revealing unsuccessful DDR events. This was also in consistency with an increase of tail moment (TM) and olive tail moment (OTM) in Dox-treated GIST and STS cells cultured in presence of Akt inhibitor after Dox washout. Altogether, our data illustrates that inhibition of AKT signaling is STS and GIST might potentiate the cytotoxic effect of topoisomerase II inhibitors via attenuating the homology-mediated DNA repair.     

Aggregation Processes Modeling in Physical-Chemical Systems

In article, the methodology of mathematical modeling of periodic reactors with agitating in the conditions of formation and sedimentation of insoluble solid phase in a working zone on the basis of diffusive model is suggested. Also equations for calculation of the general concentration and average order of clusters of insoluble phase in the periodic reactor are offered. The methodology of calculation of processes of insoluble solid phase aggregation in systems with chemical reactions of the first and pseudo-first orders is developed, namely： equation for calculation of evolution of total clusters＇ number and average order of globules in system are developed, by taking into account kinetic constants of chemical reaction and elements of aggregation matrix.     

Geographic Variability of Rainfall Erosivity Estimation and Impact on Construction Site Erosion Control Design

The Revised Universal Soil Loss Equation (RUSLE) is used often by erosion control planners to estimate the soil loss from urban construction sites when sizing sediment ponds and determining the soil loss under vegetative mats. This project used the existing, complete-year rainfall record for 27 sites in the state of Pennsylvania to compare the USDA isoerodent maps to the annual rainfall erosivity, R, values calculated using the USEPA equations for the National Resource Conservation Service Type II rainfall. The USDA and USEPA maps showed a general trend of increasing median annual R from west-to-east and north-to-south. A trend analysis relating the median R values calculated during this project to geographic location had similar, large-scale geographic trends as the USDA and USEPA maps. However, the R values more closely followed a combination of the annual rainfall pattern and topography (the Appalachian mountains bisect the state). Two case studies of the impacts of these calculations were developed to show the impact of using different values of R on the design of sediment ponds and predicting vegetation establishment. The results of these scenarios indicate that the source of data to predict R can affect the frequency and cost of sediment pond maintenance and may under-predict the protection level required of a vegetated erosion control mat.     

Synthesis method of nanomaterials by pulsed plasma in liquid

A new synthesis method of nanomaterials using pulsed plasma in liquid by the low voltage spark discharge is presented. The fullerene C60 and TiO nanopowder were for the first time synthesized by electric discharge method in liquid. The purity of C60 was >99%, which is much higher than those by the conventional arc plasma in inert gas methods (less than 80% C60 and 20% C70 and other fullerenes). Copper nanoparticles prepared by this method were smaller than those by arc method by a factor of >5. The pulsed plasma in liquid enables us to quench from plasma state, by which we can synthesize nanomaterials, metastable materials, etc. In addition, the applied power is 100 times smaller than those of arc discharge.