In situ transmission electron microscopy observation of silver oxidation in ionized/atomic gas

The interaction between silver and ionized and atomic gas was observed directly by in situ transmission electron microscopy with an environmental cell for the first time. The electron beam provides dual functions as the source of both gas ionization and imaging. The concentration of ionized gas was tuned via adjusting the current density of the electron beam. Oxidation of the silver is observed in situ, indicating the presence of ionized and/or atomic oxygen. The evolution of microstructure and phase constituents was characterized. Then the oxidation rate was measured, and the relationships among grain size, mass transport rate, and electron flux were characterized. The role of the electron beam is discussed, and the results are rationalized with respect to ex situ results from the literature.     

Oxidative dehydrogenation of <Emphasis Type="Italic">n</Emphasis>-butenes to 1,3-butadiene over BiMoFe<Subscript>0.65</Subscript>P<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> catalysts: effect of phosphorous contents

A series of BiMoFe_0.65P _x oxide catalysts with varying phosphorous contents from 0.0 to 0.6 mol ratio were prepared by a co-precipitation method, and oxidative dehydrogenation (ODH) was carried out to produce 1,3-butadiene (BD) from n-butenes. The physico-chemical properties of the oxide catalysts were characterized by X-ray diffraction (XRD), Raman spectroscopy, N₂ sorption, and NH₃ and 1-butene temperature-programmed desorption (TPD). Among the catalysts studied here, BiMoFe_0.65P_0.1 oxide catalyst showed the highest conversion and selectivity to BD. From the result of 1-butene TPD, the higher catalytic activity is related to the amount of weakly bounded intermediate and the desorbing temperature of strongly bounded intermediates. Also, the higher catalytic activity likely originates from the acidity of the BiMoFe_0.65P_0.1 oxide catalyst; its acidity was higher than that of phosphorous-free oxide catalyst and further contained other oxide catalysts. BiMoFe_0.65P_0.1 oxide catalyst is stable and no significant deactivation for 100 h ODH reaction was shown.     

Hard X‐ray microbeam lithography using a Fresnel zone plate with a long focal length

Focused hard X‐ray microbeams for use in X‐ray nanolithography have been investigated. A 7.5 keV X‐ray beam generated at an undulator was focused to about 3 µm using a Fresnel zone plate fabricated on silicon. The focused X‐ray beam retains a high degree of collimation owing to the long focal length of the zone plate, which greatly facilitates hard X‐ray nanoscale lithography. The focused X‐ray microbeam was successfully utilized to fabricate patterns with features as small as 100 nm on a photoresist.     

Optical fiber-coupled InGaAs-based terahertz time-domain spectroscopy system

The successful demonstration of an optical fiber-coupled terahertz time-domain spectroscopy (THz-TDS) system is described in this study. The terahertz output power of the emitter with two optical band rejection filters was 132 nW, which is an improvement of 70% over the output power without any filters. This improvement is due to the suppression of an optical modulated signal that is reverse-generated when an alternating current bias exceeding a certain threshold is applied to the emitter. Under the optimal alignment conditions, the terahertz detector in a fiber-coupled THz-TDS system clearly measured water vapor dips in the free space.     

Direct measurement of active thiol metabolite levels of clopidogrel in human plasma using tris(2‐carboxyethyl)phosphine as a reducing agent by LC–MS/MS

A simple, robust, and rapid LC–MS/MS method has been developed and validated for the simultaneous quantitation of clopidogrel and its active metabolite (AM) in human plasma. Tris(2‐carboxyethyl)phosphine (TCEP) was used as a reducing agent to detect the AM as a disulfide‐bonded complex with plasma proteins. Mixtures of TCEP and human plasma were deproteinized with acetonitrile containing 10 ng/mL of clopidogrel‐d₄ as an internal standard (IS). The mixtures were separated on a C₁₈ RP column with an isocratic mobile phase consisting of 0.1% formic acid in acetonitrile and water (90:10, v/v) at a flow rate of 0.3 mL/min. Detection and quantification were performed using ESI‐MS. The detector was operated in selected reaction‐monitoring mode at m/z 322.0→211.9 for clopidogrel, m/z 356.1→155.2 for the AM, and m/z 326.0→216.0 for the IS. The linear dynamic range for clopidogrel and its AM were 0.05–20 and 0.5–200 ng/mL, respectively, with correlation coefficients (r) greater than 0.9976. Precision, both intra‐ and interday, was less than 8.26% with an accuracy of 87.6–106%. The validated method was successfully applied to simultaneously analyze clinical samples for clopidogrel and its AM.     

Supramolecular Cl⋅⋅⋅H and O⋅⋅⋅H Interactions in Self‐Assembled 1,5‐Dichloroanthraquinone Layers on Au(111)

The role of halogen bonds in self‐assembled networks for systems with Br and I ligands has recently been studied with scanning tunneling microscopy (STM), which provides physical insight at the atomic scale. Here, we study the supramolecular interactions of 1,5‐dichloroanthraquinone molecules on Au(111), including Cl ligands, by using STM. Two different molecular structures of chevron and square networks are observed, and their molecular models are proposed. Both molecular structures are stabilized by intermolecular Cl???H and O???H hydrogen bonds with marginal contributions from Cl‐related halogen bonds, as revealed by density functional theory calculations. Our study shows that, in contrast to Br‐ and I‐related halogen bonds, Cl‐related halogen bonds weakly contribute to the molecular structure due to a modest positive potential (σ hole) of the Cl ligands.     

Transactivation of bad by vorinostat-induced acetylated p53 enhances doxorubicin-induced cytotoxicity in cervical cancer cells

Vorinostat (VOR) has been reported to enhance the cytotoxic effects of doxorubicin (DOX) with fewer side effects because of the lower DOX dosage in breast cancer cells. In this study, we investigated the novel mechanism underlying the synergistic cytotoxic effects of VOR and DOX co-treatment in cervical cancer cells HeLa, CaSki and SiHa cells. Co-treatment with VOR and DOX at marginal doses led to the induction of apoptosis through caspase-3 activation, poly (ADP-ribose) polymerase cleavage and DNA micronuclei. Notably, the synergistic growth inhibition induced by the co-treatment was attributed to the upregulation of the pro-apoptotic protein Bad, as the silencing of Bad expression using small interfering RNA (siRNA) abolished the phenomenon. As siRNA against p53 did not result in an increase in acetylated p53 and the consequent upregulation of Bad, the observed Bad upregulation was mediated by acetylated p53. Moreover, a chromatin immunoprecipitation analysis showed that the co-treatment of HeLa cells with VOR and DOX increased the recruitment of acetylated p53 to the bad promoter, with consequent bad transactivation. Conversely, C33A cervical cancer cells containing mutant p53 co-treated with VOR and DOX did not exhibit Bad upregulation, acetylated p53 induction or consequent synergistic growth inhibition. Together, the synergistic growth inhibition of cervical cancer cell lines induced by co-treatment with VOR and DOX can be attributed to the upregulation of Bad, which is induced by acetylated p53. These results show for the first time that the acetylation of p53, rather than histones, is a mechanism for the synergistic growth inhibition induced by VOR and DOX co-treatments.     

Presence of multiple peripheral circadian oscillators in the tissues controlling voiding function in mice

Circadian clocks are the endogenous oscillators that harmonize a variety of physiological processes within the body. Although many urinary functions exhibit clear daily or circadian variation in diurnal humans and nocturnal rodents, the precise mechanisms of these variations are as yet unclear. In the present study, we demonstrate that Per2 promoter activity clearly oscillates in neonate and adult bladders cultured ex vivo from Per2::Luc knock-in mice. In subsequent experiments, we show that multiple local oscillators are operating in all the bladder tissues (detrusor, sphincter and urothelim) and the lumbar spinal cord (L4–5) but not in the pontine micturition center or the ventrolateral periaqueductal gray of the brain. Accordingly, the water intake and urine volume exhibited daily and circadian variations in young adult wild-type mice but not in Per1^−/−Per2^−/− mice, suggesting a functional clock-dependent nature of the micturition rhythm. Particularly in PDK mice, the water intake and urinary excretion displayed an arrhythmic pattern under constant darkness, and the amount of water consumed and excreted significantly increased compared with those of WT mice. These results suggest that local circadian clocks reside in three types of bladder tissue and the lumbar spinal cord and may have important roles in the circadian control of micturition function.     

Doubling the Capacity of Lithium Manganese Oxide Spinel by a Flexible Skinny Graphitic Layer

By coating nanoparticular lithium manganese oxide (LMO) spinel with a few layers of graphitic basal planes, the capacity of the material reached up to 220 mA h g^?1 at a cutoff voltage of 2.5 V. The graphitic layers 1) provided a facile electron‐transfer highway without hindering ion access and, more interestingly, 2) stabilized the structural distortion at the 3 V region reaction. The gain was won by a simple method in which microsized LMO was ball‐milled in the presence of graphite with high energy. Vibratory ball milling pulverized the LMO into the nanoscale, exfoliated graphite of less than 10 layers and combined them together with an extremely intimate contact. Ab initio calculations show that the intrinsically very low electrical conductivity of the tetragonal phase of the LMO is responsible for the poor electrochemical performance in the 3 V region and could be overcome by the graphitic skin strategy proposed.     

Unravelling the Complex LiOH-Based Cathode Chemistry in Lithium–Oxygen Batteries**

The LiOH-based cathode chemistry has demonstrated potential for high-energy Li−O₂ batteries. However, the understanding of such complex chemistry remains incomplete. Herein, we use the combined experimental methods with ab initio calculations to study LiOH chemistry. We provide a unified reaction mechanism for LiOH formation during discharge via net 4 e⁻ oxygen reduction, in which Li₂O₂ acts as intermediate in low water-content electrolyte but LiHO₂ as intermediate in high water-content electrolyte. Besides, LiOH decomposes via 1 e⁻ oxidation during charge, generating surface-reactive hydroxyl species that degrade organic electrolytes and generate protons. These protons lead to early removal of LiOH, followed by a new high-potential charge plateau (1 e⁻ water oxidation). At following cycles, these accumulated protons lead to a new high-potential discharge plateau, corresponding to water formation. Our findings shed light on understanding of 4 e⁻ cathode chemistries in metal–air batteries.