Mechanical properties and bioactivity of β-Ca2SiO4 ceramics synthesized by spark plasma sintering

Bioactive beta-dicalcium silicate ceramics (β-Ca₂SiO₄) were fabricated by spark plasma sintering (SPS). The relative density of as-prepared β-Ca₂SiO₄ ceramics reached 98.1% when sintered at 1150 °C, leading to great improvement in bending strength (293 MPa), almost 10 times higher than that of the specimen prepared by conventional pressureless sintering (PLS). High fracture toughness (3.0 MPa m^1/2) and Vickers hardness (5.8 GPa) of β-Ca₂SiO₄ ceramics were also achieved by SPS at 1150 °C. The simulated body fluid (SBF) results showed that β-Ca₂SiO₄ ceramics had a good in vitro bioactivity to induce hydraxyapatite (HAp) formation on their surface, which suggests that β-Ca₂SiO₄ ceramics are promising candidates for load-bearing bone implant materials.     

Mycobacterium tuberculosis Acetyltransferase Suppresses Oxidative Stress by Inducing Peroxisome Formation in Macrophages

Mycobacterium tuberculosis (Mtb) inhibits host oxidative stress responses facilitating its survival in macrophages; however, the underlying molecular mechanisms are poorly understood. Here, we identified a Mtb acetyltransferase (Rv3034c) as a novel counter actor of macrophage oxidative stress responses by inducing peroxisome formation. An inducible Rv3034c deletion mutant of Mtb failed to induce peroxisome biogenesis, expression of the peroxisomal β-oxidation pathway intermediates (ACOX1, ACAA1, MFP2) in macrophages, resulting in reduced intracellular survival compared to the parental strain. This reduced virulence phenotype was rescued by repletion of Rv3034c. Peroxisome induction depended on the interaction between Rv3034c and the macrophage mannose receptor (MR). Interaction between Rv3034c and MR induced expression of the peroxisomal biogenesis proteins PEX5p, PEX13p, PEX14p, PEX11β, PEX19p, the peroxisomal membrane lipid transporter ABCD3, and catalase. Expression of PEX14p and ABCD3 was also enhanced in lungs from Mtb aerosol-infected mice. This is the first report that peroxisome-mediated control of ROS balance is essential for innate immune responses to Mtb but can be counteracted by the mycobacterial acetyltransferase Rv3034c. Thus, peroxisomes represent interesting targets for host-directed therapeutics to tuberculosis.     

Imbalanced Classification in Diabetics Using Ensembled Machine Learning

Diabetics is one of the world’s most common diseases which are caused by continued high levels of blood sugar. The risk of diabetics can be lowered if the diabetic is found at the early stage. In recent days, several machine learning models were developed to predict the diabetic presence at an early stage. In this paper, we propose an embedded-based machine learning model that combines the split-vote method and instance duplication to leverage an imbalanced dataset called PIMA Indian to increase the prediction of diabetics. The proposed method uses both the concept of over-sampling and under-sampling along with model weighting to increase the performance of classification. Different measures such as Accuracy, Precision, Recall, and F1-Score are used to evaluate the model. The results we obtained using K-Nearest Neighbor (kNN), Naïve Bayes (NB), Support Vector Machines (SVM), Random Forest (RF), Logistic Regression (LR), and Decision Trees (DT) were 89.32%, 91.44%, 95.78%, 89.3%, 81.76%, and 80.38% respectively. The SVM model is more efficient than other models which are 21.38% more than exiting machine learning-based works.     

Irradiation-induced modifications and PEC response - A case study of SrTiO3 thin films irradiated by 120 MeV Ag ions

This paper deals with a study on the effect of 120 MeV Ag⁹⁺ ion irradiation on photoelectrochemical properties of SrTiO₃ thin films deposited on Indium doped Tin Oxide (ITO) coated glass by sol-gel spin-coating technique. The structural evolution in the pristine and irradiated films was determined by X-ray diffraction and X-ray photoelectron spectroscopy. Surface morphology was studied by Atomic Force Microscopy (AFM) and optical measurements were done by UV-visible absorption spectroscopy. Irradiation of SrTiO₃ thin films was found to be effective in improving its photoelectrochemical properties. A noticeable decrease in the average grain diameter from 36 to 26 nm, reduction in bandgap from 3.55 to 3.43 eV and increase in roughness after irradiation contributed in enhancing photoelectrochemical activity of SrTiO₃ thin films. Thin films irradiated at fluence 3 × 10¹² ions cm⁻², when used in PEC cell exhibited enhanced photocurrent of 0.16 mA cm⁻² at zero bias conditions, which was four times higher than that of the unirradiated sample.     

The opportunities of networks of research-practice partnerships and why CSCL should not give up on large-scale educational change

This squib continues the ongoing conversation put forward by Wise and Schwarz around the direction and future of CSCL. We focus here on the question of whether or not CSCL should seek to make educational change. Here, we take the affirmative position by conceptualizing the network of design-centric research practice partnerships. We illustrate how this could work through an ongoing instantiation called Taking Citizen Science to School, a multi-year research center with joint funding from research and practice-based governmental institutions.     

Effectiveness of Biomaterial Coating on Bone Density Diagnosis Using Modulated Thermal Wave Imaging: A Numerical Study

Russian Journal of Nondestructive Testing - Active thermography is one of the promising painless techniques for bone density detection. It can defeat constraints of conventional diagnostic...     

Adolescents' implicit theories predict desire for vengeance after peer conflicts: Correlational and experimental evidence.

Why do some adolescents respond to interpersonal conflicts vengefully, whereas others seek more positive solutions? Three studies investigated the role of implicit theories of personality in predicting violent or vengeful responses to peer conflicts among adolescents in Grades 9 and 10. They showed that a greater belief that traits are fixed (an entity theory) predicted a stronger desire for revenge after a variety of recalled peer conflicts (Study 1) and after a hypothetical conflict that specifically involved bullying (Study 2). Study 3 experimentally induced a belief in the potential for change (an incremental theory), which resulted in a reduced desire to seek revenge. This effect was mediated by changes in bad-person attributions about the perpetrators, feelings of shame and hatred, and the belief that vengeful ideation is an effective emotion-regulation strategy. Together, the findings illuminate the social–cognitive processes underlying reactions to conflict and suggest potential avenues for reducing violent retaliation in adolescents. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Experimental and first-principles theoretical studies on Ag-doped cuprous oxide as photocathode in photoelectrochemical splitting of water

Nanostructured thin films of undoped and Ag-doped cuprous oxide were deposited on indium tin oxide-coated glass substrate using simple spray pyrolysis method for their use as photocathode in photoelectrochemical (PEC) cell for solar energy based water splitting. Combination of experiments and first-principles density functional theory based calculations was used to determine and understand the effect of Ag substitution on electronic structure and PEC performance. Thin films were characterized using XRD, FE-SEM, UV–Vis spectroscopy and PEC measurements. The results of DFT calculations show that the top of valence band and bottom of conduction band of undoped Cu₂O lie at Г point of brillouin zone, respectively, suggesting that pure Cu₂O is a direct band gap material. Minimal changes appear in the band gap and band gap energies in the Ag-doped Cu₂O system, keeping it still a direct band gap material. A defect band appearance can be seen between ?4 and ?5 eV in the valence band consisting mainly of Ag 4d states and can be explained by a stronger interaction between the Ag 4d and O 2p, due to the larger Ag size. Ag-doped samples exhibit improved conductivity and fourfold increase in photocurrent density with respect to undoped samples.     

Nanostructured SrTiO3 thin films sensitized by Cu2O for photoelectrochemical hydrogen generation

We prepared nanostructured thin films of pristine SrTiO₃, Cu₂O and SrTiO₃/Cu₂O heterojunction with varying the thickness of Cu₂O. SrTiO₃ and Cu₂O thin films were deposited on ITO (Sn:In₂O₃) glass substrate using sol–gel spin-coating technique and spray pyrolysis method respectively. Samples were characterized using XRD (X-ray diffractometry), SEM (Scanning electron microscopy), and UV–Visible absorption spectroscopy. Nanostructured thin films of pristine SrTiO₃, Cu₂O and SrTiO₃/Cu₂O heterojunction systems were used as photoelectrode in the Photoelectrochemical (PEC) cell for water splitting reaction. Maximum photocurrent density value of 2.44 mA cm⁻² at 0.95 V/SCE were observed for SrTiO₃/Cu₂O heterojunction photoelectrode with 454 nm thickness, which was approximately 34 times higher than pristine SrTiO₃ thin film. Increased photocurrent density observed for the heterojunction can be attributed to the improved conductivity and better separation of the photogenerated charge carriers at the SrTiO₃/Cu₂O interface.     

Design and simulation of RF MEMS shunt capacitive switch with non-uniform meanders for C-band applications

Microsystem Technologies - This paper presents, the design and simulation of RF MEMS shunt capacitive switch. The electromechanical and electromagnetic analysis of the switch has been done using...