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To clarify the influence of various molar concentrations of vinylidene fluoride (VDF) on the piezoelectric and acoustic emission (AE) reception performances of poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] sensors, we systematically investigated the crystal structures and the dielectric and ferroelectric properties of P(VDF-TrFE) films with different compositions of VDF and TrFE monomers and found that low proportion (<30 mol%) TrFE as a wedge inserted into molecular chains of P(VDF-TrFE) will not only improve the fraction of regular β-phase crystal grains but also decrease the dielectric constant (εr) of these copolymers, which favors the piezoelectric voltage coefficient (g33) of this P(VDF-TrFE) film. As such, a considerable remanent electric polarization (Pr ~ 11.4 μC cm2) under 200 MV/m and a large piezoelectric coefficient (d33 ~ -25 pC/N) are obtained in P(VDF-TrFE) 80/20-mol% films. It is worth noting that a sensor made from P(VDF-TrFE) 80/20 mol% shows an attractive AE reception property of approximately 84 dB, a high signal voltage of above 10 mV from time-domain analysis, and a large signal voltage of above 4 mV from frequency-domain analysis, which are close to standard lead zirconate titanate (PZT) sensors. Considering its unique characters of flexibility, no required stretching, easily shaped, having high thermal Faille temperatures (Tc ~ 135.7 ∘C), etc., P(VDF-TrFE) piezoelectric film is considered a promising material for sensors, actuators, and energy transfer units. [ABSTRACT FROM AUTHOR]

High quality epitaxial indium oxide (In 2 O 3) films were prepared on the a-plane sapphire [Al 2 O 3 (110)] substrates at 570–690 °C by the metal-organic chemical vapor deposition (MOCVD) technique. The properties of structure, morphology and photoelectricity for the obtained films were studied at length. The film deposited at 650 °C showed the best crystalline quality with an out-of-plane epitaxial relationship of In 2 O 3 (111)∥Al 2 O 3 (110). This film also had the highest Hall mobility of 42 cm2V−1s−1 with a lowest resistivity of 5 × 10−3 Ω cm and a lowest carrier concentration of 3 × 1019 cm−3. All the samples possessed high average transparencies (over 83%) in the visible region and wide optical band gaps (∼3.70 eV). The In 2 O 3 films with high crystalline quality as well as satisfactory photoelectrical characteristics can be extensively used in the manufacture of various semiconductor devices. • Epitaxial In 2 O 3 films were deposited on a-plane sapphire substrates by MOCVD. • The sample prepared at 650 °C presents the best crystalline quality. • The highest Hall mobility of the films is 42 cm2V−1s−1. • The average transmittance of the films in the visible range exceeds 83%. [ABSTRACT FROM AUTHOR]

Human PRS1, which is indispensable for the biosynthesis of nucleotides, deoxynucleotides and their derivatives, is associated directly with multiple human diseases because of single base mutation. However, a molecular understanding of the effect of these mutations is hampered by the lack of understanding of its catalytic mechanism. Here, we reconstruct the 3D EM structure of the PRS1 apo state. Together with the native stain EM structures of AMPNPP, AMPNPP and R5P, ADP and the apo states with distinct conformations, we suggest the hexamer is the enzymatically active form. Based on crystal structures, sequence analysis, mutagenesis, enzyme kinetics assays, and MD simulations, we reveal the conserved substrates binding motifs and make further analysis of all pathogenic mutants. [ABSTRACT FROM AUTHOR]

Gas vesicles are gas-filled proteinaceous organelles that provide buoyancy for bacteria and archaea. A gene cluster that is highly conserved in various species encodes about 8-14 proteins (Gvp proteins) that are involved in the formation of gas vesicles. Here, the first crystal structure of the gas vesicle protein GvpF from Microcystis aeruginosa PCC 7806 is reported at 2.7 Å resolution. GvpF is composed of two structurally distinct domains (the N-domain and C-domain), both of which display an α+β class overall structure. The N-domain adopts a novel fold, whereas the C-domain has a modified ferredoxin fold with an apparent variation owing to an extension region consisting of three sequential helices. The two domains pack against each other via interactions with a C-terminal tail that is conserved among cyanobacteria. Taken together, it is concluded that the overall architecture of GvpF presents a novel fold. Moreover, it is shown that GvpF is most likely to be a structural protein that is localized at the gas-facing surface of the gas vesicle by immunoblotting and immunogold labelling-based tomography. [ABSTRACT FROM AUTHOR]

Human endocannabinoid systems modulate multiple physiological processes mainly through the activation of cannabinoid receptors CB1 and CB2. Their high sequence similarity, low agonist selectivity, and lack of activation and G protein-coupling knowledge have hindered the development of therapeutic applications. Importantly, missing structural information has significantly held back the development of promising CB2-selective agonist drugs for treating inflammatory and neuropathic pain without the psychoactivity of CB1. Here, we report the cryoelectron microscopy structures of synthetic cannabinoid-bound CB2 and CB1 in complex with G i , as well as agonist-bound CB2 crystal structure. Of important scientific and therapeutic benefit, our results reveal a diverse activation and signaling mechanism, the structural basis of CB2-selective agonists design, and the unexpected interaction of cholesterol with CB1, suggestive of its endogenous allosteric modulating role. • 3D structures of CB2-AM12033-G i , CB1-AM841-G i , and CB2-AM12033 are determined • Structural evidence of G protein selectivity by CB1 and CB2 is identified • MD simulations reveal the distinct binding behavior of HU308 in CB2 and CB1 • Cholesterol molecule as an endogenous allosteric modulator of CB1 is uncovered Structure and simulations of cannabinoid receptors CB2 and CB1 in their inactive, active-like, and activated signaling states reveal residue differences that may provide G protein selectivity, the distinct binding behavior of CB2 agonists in CB2 and CB1, as well as evidence for modulation of CB1 by cholesterol binding. [ABSTRACT FROM AUTHOR]