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Background: Our previous study have demonstrated chronic intermittent hypoxia (CIH) induced cardiomyocyte apoptosis and cardiac dysfunction. However, the molecular mechanisms are complicated and varied. In this study, we first investigated the CaMKIIγ expression and signaling pathway in the pathogenesis of cardiomyocyte apoptosis after CIH. Methods: Rats were separated into CIH and Normoxia groups, and H9c2 cells were divided into Control and CIH + 8 h groups. Rat body weight (BW) was markedly gained from two to six weeks. Furthermore, CIH decreased cardiac dysfunction, damaged cellular structure, induced myocardial fibrosis, and promoted cardiomyocyte apoptosis by HE, masson, sirius-red, and TUNEL staining. Western blot, immunohistochemical, immunofluorescence, double immunofluorescence staining were performed to investigate CaMKIIγ, Bcl-2, Bax, Caspase 3, HIF-1 protein expression. Results: Heart weight (HW) and HW/BW ratio in CIH group was markedly gained compared with the Normoxia group. CaMKIIγ expression was notably increased after CIH, and mainly expressed in the cytoplasm in vivo and vitro. The results of HIF-1 expression have the same trend of CaMKIIγ expression and cardiomyocyte apoptosis. In addition, the co-localizations of CaMKIIγ with Caspase 3, and CaMKIIγ with HIF-1 were observed by double immunofluorescence staining. Conclusions: These results indicated increased CaMKIIγ expression advances CIH-induced cardiomyocyte apoptosis via HIF-1 signaling pathway, which afford a new insight and provide a potential therapy for OSA patients. [ABSTRACT FROM AUTHOR]

Although high-applied electric field can usually generate high energy storage performance (ESP) for most dielectric materials, the presence of high risk at high electric field and large cost of insulation technology are the main obstacles that critically restrict the actual applications of dielectric ceramics in the energy storage area. Herein, simultaneously realizing high energy storage density (Wrec)/efficiency (η) and charge–discharge performance under low working electric fields is proposed in relaxor ferroelectrics via combining the non-ergodic and ergodic relaxor state (NR-ER) and dominated ER features. Based on this idea, a high Wrec (2.03 J/cm3) and favorable η (72%), together with excellent frequency dependence (0.5–100 Hz), moderate temperature stability (20–140 °C, and satisfactory fatigue endurance (100–105 cycles), can be simultaneously achieved in 0.3[0.955(Bi0.5Na0.5)TiO3–0.045Ba(Al0.5Ta0.5)O3]–0.7Sr0.3(Bi0.7Na0.67Li0.03)0.5TiO3 (BNT–BAT–0.7SBNLT) ceramic at a low electric field of 200 kV/cm. Moreover, the indicated ceramics also possess great charge–discharge performance at 140 kV/cm, featured by a large power density PD of 46.2 MW/cm3, discharge energy density Wd of 0.62 J/cm3, fast charge-discharge rate t0.9 of 210 ns, and excellent cycling reliability. Thus, the designed BNT–BAT–0.7SBNLT ceramic possesses superior comprehensive ESP under low electric field, which has broad prospects in practical high-power ceramic capacitors applications. [ABSTRACT FROM AUTHOR]

Reverse transcription of the HIV-1 viral RNA genome (vRNA) is an integral step in virus replication. Upon viral entry, HIV-1 reverse transcriptase (RT) initiates from a host tRNALys3 primer bound to the vRNA genome and is the target of key antivirals, such as non-nucleoside reverse transcriptase inhibitors (NNRTIs). Initiation proceeds slowly with discrete pausing events along the vRNA template. Despite prior medium-resolution structural characterization of reverse transcriptase initiation complexes (RTICs), higher-resolution structures of the RTIC are needed to understand the molecular mechanisms that underlie initiation. Here we report cryo-EM structures of the core RTIC, RTIC–nevirapine, and RTIC–efavirenz complexes at 2.8, 3.1, and 2.9 Å, respectively. In combination with biochemical studies, these data suggest a basis for rapid dissociation kinetics of RT from the vRNA–tRNALys3 initiation complex and reveal a specific structural mechanism of nucleic acid conformational stabilization during initiation. Finally, our results show that NNRTIs inhibit the RTIC and exacerbate discrete pausing during early reverse transcription. Initiation of HIV-1 reverse transcription occurs at the host tRNALys3, which forms a complex with the 5' end of the HIV-1 viral RNA and reverse transcriptase (RT). Here, the authors present the 2.8 Å cryo-EM structure of a minimal HIV-1 RT–vRNA–tRNALys3 initiation complex (miniRTIC), and miniRTIC structures with the bound non-nucleoside reverse transcriptase inhibitors nevirapine and efavirenz at 3.1 and 2.9 Å resolution, respectively. [ABSTRACT FROM AUTHOR]

The applied electric field to drive intended large strain response in BiNaTiO-based piezoelectric ceramics is usually high (mostly with E ≥ 60 kV/cm) and remains a long-standing drawback for actual actuator applications. In this work, we report 〈001〉 oriented (1− x) (0.83BiNaTiO-0.17BiKTiO)- xBaTiO (BNT-BKT-BT) lead-free piezoelectric ceramics using BT as the template particles to tailor the strain behavior under a low driving field. The strain response exhibited an increasing trend with the increasing grain orientation, and remarkably giant S / E of 800 pm/V was acquired under a relatively low electric field of 45 kV/cm in the optimized microstructure for textured BNT-BKT-1BT ceramics compared with the reported lead-free Bi-based perovskite ceramics. Furthermore, the achieved textured ceramics showed prominent electric field- and temperature-dependent strain characteristic featured by both a high room-temperature S / E of 621 pm/V under a very low driving field of 35 kV/cm and an achievable large S / E of 531 pm/V with almost vanished hysteretic behavior at high temperature. Our work may be helpful for designing BNT-based lead-free materials with promising strain response and thus provides a new approach to resolve this drawback of BNT-based lead-free piezoelectric ceramics. [ABSTRACT FROM AUTHOR]

Sulfonated mesoporous ZrO was prepared by a facile one-pot hydrothermal process, using a mixture of ZrOCl·8HO and sodium dodecyl sulfonate in a NaOH solution, and subsequent calcination of the inorganic/organic intermediate. The influence of NaOH concentration, hydrothermal and calcination temperature on the structural and textural properties of the final products was investigated. Increasing the NaOH concentration gave rise to the transformation from tetragonal to monoclinic and then to tetragonal phase, whereas the increase of hydrothermal temperature led to the tetragonal-to-monoclinic phase transformation. As the NaOH concentration and hydrothermal temperature were increased, a narrow pore size distribution was turned into a multi-modal pore size distribution resulting from regular mesopores and interparticle voids. Accordingly, the incorporated sulfonate anions were oxidized into sulphate anions. After the calcination of 550 °C, the sulfonated products possessed tetragonal crystalline phase with average pore diameter of 4.2 nm and surface area of 108 mg. [ABSTRACT FROM AUTHOR]

Glomeruli are functional units in the olfactory system. The mouse olfactory bulb contains roughly 2,000 glomeruli, each receiving inputs from olfactory sensory neurons (OSNs) that express a specific odorant receptor gene. Odors typically activate many glomeruli in complex combinatorial patterns and it is unknown which features of neuronal activity in individual glomeruli contribute to odor perception. To address this, we used optogenetics to selectively activate single, genetically identified glomeruli in behaving mice. We found that mice could perceive the stimulation of a single glomerulus. Single-glomerulus stimulation was also detected on an intense odor background. In addition, different input intensities and the timing of input relative to sniffing were discriminated through one glomerulus. Our data suggest that each glomerulus can transmit odor information using identity, intensity and temporal coding cues. These multiple modes of information transmission may enable the olfactory system to efficiently identify and localize odor sources. [ABSTRACT FROM AUTHOR]

NiMn2−xMgxO4 (0 ≤ x ≤ 0.4) ceramics have been studied by powder x-ray diffraction (XRD), infrared (IR) spectroscopy, and thermogravimetric analysis. NiMn2−xMgxO4 ceramics are all single-phase with spinel structure. XRD and IR spectroscopy results indicate that Mg2+ ions occupy A- and B-site of spinel lattice, which inhibits the formation of cation vacancies. Moreover, Mg2+ substitution enhances the tolerance of the oxidation in air. As a result, Mg substitution leads to a significant increase in ρ25, temperature coefficient of resistivity B25/85, and activation energy, which improves the aging property of NiMn2−xMgxO4 negative temperature coefficient thermistors. [ABSTRACT FROM PUBLISHER]

The structure-property relationships in BaSrTiSiO with y=0.00, 0.01, 0.02, 0.05, 0.10 and 0.20 ceramics have been studied by using X-ray diffraction, electron microscopy and dielectric spectroscopy. An increase of Si concentration is not favorable for the stability of the perovskite structure, which results in the formation of BaTiSiO5 secondary phase. The dielectric peaks of samples are suppressed, broadened and shifted to low temperature with increasing Si concentration. Permittivity and Q value are reduced gradually with increasing Si concentration, due to growing of second BaTiSiO phase. The tunability ( T) still remains ∼18.0% under 60 kV/cm biasing for the samples with y⩽0.10. The best combination of microwave dielectric properties are obtained for the composition of y=0.10: ɛ=531, Q=391 (at 1.610 GHz) and T=17.7%. [ABSTRACT FROM AUTHOR]

BaTi4O9-doped Ba0.6Sr0.4TiO3 (BST) composite ceramics were prepared by the conventional solid-state reaction and their structure, dielectric nonlinear characteristics and microwave dielectric properties were investigated. The secondary phase of the orthorhombic structure Ba4Ti13O30 is formed among BST composite ceramics with the increase of BaTi4O9. At the same time, a duplex or bimodal grains size distribution shows fine grains in a coarse grain matrix. The degree of frequency dispersion of dielectric permittivity below T m is increased initially and then decreased with respect to BaTi4O9. As the BaTi4O9 content increases, the tunability of composite ceramics decreases, while the Q value increases. Interestingly, 70 wt% BaTi4O9-doped BST has a tunability ∼4.0% (under 30 kV/cm biasing) versus a permittivity ∼68 and quality factor ∼134.1 (at ∼3.2 GHz). [ABSTRACT FROM AUTHOR]

In many species, survival depends on olfaction, yet the mechanisms that underlie olfactory sensitivity are not well understood. Here we examine how a conserved subset of olfactory receptors, the trace amine-associated receptors (TAARs), determine odor detection thresholds of mice to amines. We find that deleting all TAARs, or even single TAARs, results in significant odor detection deficits. This finding is not limited to TAARs, as the deletion of a canonical odorant receptor reduced behavioral sensitivity to its preferred ligand. Remarkably, behavioral threshold is set solely by the most sensitive receptor, with no contribution from other highly sensitive receptors. In addition, increasing the number of sensory neurons (and glomeruli) expressing a threshold-determining TAAR does not improve detection, indicating that sensitivity is not limited by the typical complement of sensory neurons. Our findings demonstrate that olfactory thresholds are set by the single highest affinity receptor and suggest that TAARs are evolutionarily conserved because they determine the sensitivity to a class of biologically relevant chemicals. Odorous chemicals broadly activate subsets of olfactory receptors in the nose, but how individual receptors contribute to behavioral sensitivity is not clear. Here, the authors demonstrate that detection thresholds in mice are set solely by the highest affinity receptor for a given odorant. [ABSTRACT FROM AUTHOR]