Engineering de novo disulfide bond in bacterial alpha-type carbonic anhydrase for thermostable carbon sequestration

Exploiting carbonic anhydrase (CA), an enzyme that rapidly catalyzes carbon dioxide hydration, is an attractive biomimetic route for carbon sequestration due to its environmental compatibility and potential economic viability. However, the industrial applications of CA are strongly hampered by the unstable nature of enzymes. In this work, we introduced in silico designed, de novo disulfide bond in a bacterial alpha-type CA to enhance thermostability. Three variants were selected and expressed in Escherichia coli with an additional disulfide bridge. One of the variants showed great enhancement in terms of both kinetic and thermodynamic stabilities. This improvement could be attributed to the loss of conformational entropy of the unfolded state, showing increased rigidity. The variant showed an upward-shifted optimal temperature and appeared to be thermoactivated, which compensated for the lowered activity at 25 degrees C. Collectively, the variant constructed by the rapid and effective de novo disulfide engineering can be used as an efficient biocatalyst for carbon sequestration under high temperature conditions.1194Ysciescopu

Cholesteryl isobutylcarbonate

Cholesteryl isobutylcarbonate, C 32H 54O 3, contains two molecules (A and B) in the asymmetric unit. The isobutylcarbonate chain of molecule A and the isoprenoid tail of molecule B are each conformationally disordered over two positions. The two distinct molecules form separate stacks along the screw axes so that they are arranged in an antiparallel array, forming monolayers with a thickness of d 001 = 19.412 A. The central regions of the monolayers are characterized by efficient molecular packing and are separated by interface regions, which are more loosely packed.open4

Complete gate control of supercurrent in graphene p-n junctions

In a conventional Josephson junction of graphene, the supercurrent is not turned off even at the charge neutrality point, impeding further development of superconducting quantum information devices based on graphene. Here we fabricate bipolar Josephson junctions of graphene, in which a p-n potential barrier is formed in graphene with two closely spaced superconducting contacts, and realize supercurrent ON/OFF states using electrostatic gating only. The bipolar Josephson junctions of graphene also show fully gate-driven macroscopic quantum tunnelling behaviour of Josephson phase particles in a potential well, where the confinement energy is gate tuneable. We suggest that the supercurrent OFF state is mainly caused by a supercurrent dephasing mechanism due to a random pseudomagnetic field generated by ripples in graphene, in sharp contrast to other nanohybrid Josephson junctions. Our study may pave the way for the development of new gate-tuneable superconducting quantum information devices.open114344sciescopu

A Mechanistic Understanding of a Binary Additive System to Synergistically Boost Efficiency in All-Polymer Solar Cells

All-polymer solar cells are herein presented utilizing the PBDTTT-CT donor and the P(NDI2OD-T2) acceptor with 1,8-diiodooctane (DIO) and 1-chloronaphthalene (CN) binary solvent additives. A systematic study of the polymer/polymer bulk heterojunction photovoltaic cells processed from the binary additives revealed that the microstructures and photophysics were quite different from those of a pristine system. The combination of DIO and CN with a DIO/CN ratio of 3:1 (3 vol% DIO, 1 vol% CN and 96 vol% o-DCB) led to suitable penetrating polymer networks, efficient charge generation and balanced charge transport, which were all beneficial to improving the efficiency. This improvement is attributed to increase in power conversion efficiency from 2.81% for a device without additives to 4.39% for a device with the binary processing additives. A detailed investigation indicates that the changes in the polymer: polymer interactions resulted in the formation of a percolating nasnoscale morphology upon processing with the binary additives. Depth profile measurements with a two-dimensional grazing incidence wide-angle X-ray scattering confirm this optimum phase feature. Furthermore impedance spectroscopy also finds evidence for synergistically boosting the device performance.112218Ysciescopu

Dimerization-Induced Fermi-Surface Reconstruction in IrTe2

We report a de Haas-van Alphen (dHvA) oscillation study on IrTe2 single crystals showing complex dimer formations. By comparing the angle dependence of dHvA oscillations with band structure calculations, we show distinct Fermi surface reconstruction induced by a 1/5-type and a 1/8-type dimerizations. This verifies that an intriguing quasi-two-dimensional conducting plane across the layers is induced by dimerization in both cases. A phase transition to the 1/8 phase with higher dimer density reveals that local instabilities associated with intra-and interdimer couplings are the main driving force for complex dimer formations in IrTe2.X11149sciescopu

Prostate-specific extracellular vesicles as a novel biomarker in human prostate cancer

Extracellular vesicles (EVs) may play an important role in cancer development and progression. We aimed to investigate the prognostic potential of prostate-specific EVs in prostate cancer (PCa) patients. Plasma and prostate tissue were collected from patients who underwent surgery for PCa (n = 82) or benign prostatic hyperplasia (BPH, n = 28). To analyze the quantity of EVs in prostate, we performed transmission electron microscopy (TEM), immuno-TEM with CD63 and prostate-specific membrane antigen (PSMA), and immunofluorescence staining. After EV isolation from plasma, CD63 and PSMA concentration was measured using ELISA kits. PSMA-positive areas in prostate differed in patients with BPH, and low-, intermediate-, and high-risk PCa (2.4, 8.2, 17.5, 26.5%, p < 0.001). Plasma PSMA-positive EV concentration differed in patients with BPH, and low-, intermediate-, and high-risk PCa (21.9, 43.4, 49.2, 59.9 ng/mL, p < 0.001), and ROC curve analysis indicated that plasma PSMA-positive EV concentration differentiated PCa from BPH (AUC 0.943). Patients with lower plasma PSMA-positive EV concentration had greater prostate volume (50.2 vs. 33.4 cc, p < 0.001) and lower pathologic Gleason score (p = 0.025). During the median follow-up of 18 months, patients with lower plasma PSMA-positive EV concentration tended to have a lower risk of biochemical failure than those with higher levels of prostate-specific EVs (p = 0.085).11910Ysciescopu

Successive spin-flop transitions of a Neel-type antiferromagnet Li2MnO3 single crystal with a honeycomb lattice

We have carried out high magnetic field studies of single-crystalline Li2MnO3, a honeycomb lattice antiferromagnet. Its magnetic phase diagram was mapped out using magnetization measurements at applied fields up to 35 T. Our results show that it undergoes two successive meta-magnetic transitions around 9 T fields applied perpendicular to the ab plane (along the c* axis). These phase transitions are completely absent in the magnetization measured with the field applied along the ab plane. In order to understand this magnetic phase diagram, we developed a mean-field model starting from the correct Neel-type magnetic structure, consistent with our single crystal neutron diffraction data at zero field. Our model calculations succeeded in explaining the two meta-magnetic transitions that arise when Li2MnO3 enters two different spin-flop phases from the zero field Neel phase.open1187Nsciescopu

Surface Modification of TiO2 Nanoparticles with Phenyltrimethoxysilane in Dye-sensitized Solar Cells

Phenyltrimethoxysilane (PTMS) was anchored onto the sensitized TiO2 nanoparticles. This insulating molecular layer effectively inhibited the charge recombination at the interface of TiO2/electrolyte in the dye sensitized solar cells (DSCs) without sacrificing the dye-loading capacity of the nanocrystalline TiO2. DSCs using PTMS-modified TiO2 exhibited a short-circuit current (J(SC)) of 15.9 mA/cm(2), an open-circuit voltage (V-OC) of 789 mV, and a fill factor (FE) of 68.2%, yielding an overall conversion efficiency (eta) of 8.55% under 100 mW/cm(2) illumination. The resulting cell efficiency was improved by similar to 10% as compared with the reference cell.X1133Ysciescopu