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Abstract: Perovskite type catalysts with LaCoO3 and La0.9Ba0.1CoO3 compositions have been prepared by sol–gel method and their catalytic activity was studied for CO oxidation in presence of CO2, water and also for particulate matter (PM)/carbon oxidation. The catalysts were characterized using XRD, BET-SA, SEM, TPD, XPS and their catalytic activity was evaluated using a steady state gas evaluation assembly, as well as thermo gravimetric analysis. La0.8Ba0.1CoO3 catalyst shows enhanced catalytic activity as compared to LaCoO3 for CO and PM oxidation. Barium substitution appears to be responsible for low temperature activity of the catalyst by influencing redox and oxygen desorption properties as also suggested by TPD studies. [Copyright &y& Elsevier]

Analyzes the characteristics of gibberellin (GA) 20-oxidase homologous gene in apple using its isolated genomic and circular DNA clone. Identification of genes involved in GA biosynthesis; Examination of the tissue distribution of GA 20-oxidase; Changes in messenger RNA accumulation in immature seeds; Correlation between fruit growth rate and seed number.

Despite the remarkable developments of the Ugi reaction and its variants, the use of ammonia in the Ugi reaction has long been recognized as impractical and unsuccessful. Indeed, the ammonia-Ugi reaction often requires harsh reaction conditions, such as heating and microwave irradiation, and competes with the Passerini reaction, thereby resulting in low yields. This study describes a robust and practical ammonia-Ugi reaction protocol. Using originally prepared ammonium carboxylates in trifluoroethanol, the ammonia-Ugi reaction proceeded at room temperature in high yields and showed a broad substrate scope, thus synthesizing a variety of α,α-disubstituted amino acid derivatives, including unnatural dipeptides. The reaction required no condensing agents and proceeded without racemization of the chiral stereocenter of α-amino acids. Furthermore, using this protocol, we quickly synthesized a novel dipeptide, D-Leu-Aic-NH-CH 2 Ph( p -F), which exhibited a potent inhibitory activity against α-chymotrypsin with a K i value of 0.091 μM.

Electron-electron scattering on the order of a few to tens of femtoseconds plays a crucial role in the ultrafast electron dynamics of conventional metals. When mid-infrared light is used for driving and the period of light field is comparable to the scattering time in metals, unique light-driven states and nonlinear optical responses associated with the scattering process are expected to occur. Here, we use high-harmonics spectroscopy to investigate the effect of electron-electron scattering on the electron dynamics in thin film 2H-NbSe_{2} driven by a mid-infrared field. We observed odd-order high harmonics up to 9th order as well as a broadband emission from hot electrons in the energy range from 1.5 to 4.0 eV. The electron-electron scattering time in 2H-NbSe_{2} was estimated from the broadband emission to be almost the same as the period of the mid-infrared light field. A comparison between experimental results and a numerical calculation reveals that competition and cooperation between the driving and scattering enhances the nonperturbative behavior of high harmonics in metals, causing a highly nonequilibrium electronic state corresponding to several thousand Kelvin.

In this study, ultrafast transient signals were detected on a single-shot basis using chirped-pulse up-conversion spectroscopy with dispersion compensation. Unlike in the conventional time-encoding technique using chirped pulses, distortion of the ultrafast waveform was reduced by applying dispersion compensation to the chirped probe pulses and using sum-frequency generation with the chirped readout pulses. The method was applied to terahertz time-domain spectroscopy and near-infrared pump-probe spectroscopy, providing ultrafast observations with an improved temporal resolution comparable to the transform-limited pulse durations. Terahertz waveforms, Kerr rotation signals, and phonon-polariton oscillations were measured accurately with no significant waveform distortion, thereby showing the proposed scheme to be promising for single-shot pump-probe spectroscopy in a wide range of spectroscopic applications.

Floquet engineering is a promising way of controlling quantum system with photon-dressed states on an ultrafast time scale. So far, the energy structure of Floquet states in solids has been intensively investigated. However, the dynamical aspects of the photon-dressed states under ultrashort pulse have not been explored yet. Their dynamics become highly sensitive to the driving field transients, and thus, understanding them is crucial for ultrafast manipulation of a quantum state. Here, we observed the coherent exciton emission in monolayer WSe 2 at room temperature at the appropriate photon energy and the field strength of the driving light pulse using high-harmonic spectroscopy. Together with numerical calculations, our measurements revealed that the coherent exciton emission spectrum reflects the diabatic and adiabatic dynamics of Floquet states of excitons. Our results provide a previosuly unexplored approach to Floquet engineering and lead to control of quantum materials through pulse shaping of the driving field.

We demonstrate that broadband sum frequency generation (SFG) spectroscopy based on a partially incoherent supercontinuum light source can elucidate dark p-series excitons in monolayer WSe 2 encapsulated between hexagonal boron nitride (hBN) slabs. The observed 2p exciton peak energy is a few meV higher than that predicted by the Rytova-Keldysh potential model, which is originated from the Berry phase effect. Interestingly, although the radiative relaxation of the 2p exciton is weaker, the 2p exciton peak is broader than the 1s and 2s peaks, which indicates its faster dephasing than the 1s and 2s excitons. Measuring the excitation intensity and temperature dependence, we clarified that this broader linewidth is not caused by excitation- or phonon-induced dephasing, but rather by exciton-electron scattering.

Objective: This study aimed to determine if contrast medium volume (CMV) is a risk factor for acute kidney injury (AKI) during transcatheter aortic valve implantation (TAVI) via a transfemoral approach performed without major complications. All TAVI procedures performed at our institution between March 2014 and March 2018 were retrospectively reviewed. AKI was diagnosed using the Acute Kidney Injury Network classification based on the Valve Academic Research Consortium-2 definition. Procedures performed via a transapical approach and those in which circulatory dynamics failed intraoperatively were excluded., Results: Eighty-one (96.4%) of 100 patients scheduled for TAVI were enrolled; seven (8.6%) developed AKI and 74 (91.4%) did not. The serum creatinine (SCr) level was significantly higher (p < 0.05) and the estimated glomerular filtration rate was significantly lower in the AKI group (p < 0.05). The CMV was significantly higher in the AKI group (103 ml vs 84 ml, p < 0.05), as was the CMV × SCr/BW value (3.34 vs 1.49, p < 0.01). The area under the curve for CMV × SCr/BW was 0.9228 and the cut-off value was 2.99. The CMV, SCr, and estimated glomerular filtration rate affect the likelihood of AKI after transfemoral TAVI and a CMV × SCr/BW value > 2.99 accurately predicts AKI.

Synthesis of molecular containers capable of incorporating multiple fullerenes remains challenging. Reported here is that room-temperature mixing of metal ions with W-shaped bispyridine ligands featuring polyaromatic panels results in the quantitative formation of a peanut-shaped M 2 L 4 capsule. The capsule reversibly converts into two molecules of an ML 2 double tube in response to changes in the solvent. Notably, the capsule allows the incorporation of two fullerene molecules into the connected two spherical cavities at room temperature. The close proximity yet non-contact of the encapsulated C 60 molecules, with a separation of 6.4 Å, was revealed by X-ray crystallographic analysis. The resultant, unusual fullerene dimer undergoes sequential reduction within the capsule to generate (C 60 .- ) 2 , C 60 .- ⋅C 60 2- , and (C 60 2- ) 2 species. Furthermore, temperature-controlled stepwise incorporation of two C 60 molecules into the capsule is demonstrated., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Host functions of polyaromatic nanocavities were revealed by using an M 2 L 4 molecular cage and capsule. On the basis of the previously reported M 2 L 4 capsule with a closed polyaromatic cavity, a new M 2 L 4 cage (as a mixture of the isomers) was prepared by the quantitative assembly of two metal ions and four desymmetrized bispyridine ligands with a single polyaromatic panel. The obtained, open nanocavity of the cage exhibited enhanced binding abilities toward large dyes and pigments in water. For example, two molecules of coumarin dyes were bound in the nanocavity and showed strong whitish emission (up to Φ F =34 %). Furthermore, metallopigments, the sizes of which are larger than the inner cavities of the cage and capsule, were bound only in the open polyaromatic nanocavity of the cage to give water-soluble 1:1 host-guest complexes., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Oligo(ethylene oxide)s are known as widely useable yet not very interactive amphiphilic compounds. Here we report that the long amphiphilic oligomers are bound by a polyaromatic capsule in two different manners, depending on the chain length. For instance, the shorter pentamer is crammed into the isolated cavity of the capsule, whereas the longer decamer is threaded into the capsule to form a 1:1 host-guest complex in a pseudo-rotaxane fashion. These unusual bindings occur instantly, spontaneously, and quantitatively even in water at room temperature, with relatively high binding constants (K a  > 10 6  M -1 ). Isothermal titration calorimetry (ITC) studies reveal that enthalpic stabilization is a dominant driving force for both of the complexations through multiple host-guest CH-π and hydrogen-bonding interactions. Furthermore, long oligomers with an average molecular weight of 1000 Da (e.g., 22-mer) are also threaded into the capsules to give pseudo-rotaxane-shaped 2:1 host-guest complexes in water, selectively.

Biologically relevant hydrophilic molecules rarely interact with hydrophobic compounds and surfaces in water owing to effective hydration. Nevertheless, herein we report that the hydrophobic cavity of a polyaromatic capsule, formed through coordination-driven self-assembly, can encapsulate hydrophilic oligo(lactic acid)s in water with relatively high binding constants (up to K a =3×10 5  m -1 ). X-ray crystallographic and ITC analyses revealed that the unusual host-guest behavior is caused by enthalpic stabilization through multiple CH-π and hydrogen-bonding interactions. The polyaromatic cavity stabilizes hydrolyzable cyclic di(lactic acid) and captures tetra(lactic acid) preferentially from a mixture of oligo(lactic acid)s even in water., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

We found the utilization of porphyrin-based metal-organic network films composed of tetra(catechol-substituted)porphyrin (cPor) and Fe ions for robust wrapping materials of graphene oxide (GO), which can keep the dispersion state under the chemical reduction of GO to reduced graphene oxide (rGO) in water. The tetra(catechol-substituted)porphyrin (cPor) was designed for soft-wrapping methods because the aromatic porphyrin moieties can be strongly adsorbed onto the surface of GO or rGO via both π-π interactions and the catechol-Fe coordination network formation. The GO sheets covered with the cPor-Fe films were reduced chemically in water under retention of the wrapped nanostructure of the cPor-Fe/GO sheets. The obtained rGO composites after chemical reduction are characterized by using UV-vis absorption, Raman, and X-ray photoelectron spectroscopy (XPS) spectra, as well as thermogravimetric analysis and energy-dispersive X-ray spectroscopy (EDX). XPS and EDX spectra showed the presence of Fe species, which originates from the coordinated Fe-catechol nodes in the wrapped cPor-Fe films. The wrapped rGO sheets could be easily handled in water because of their high solubility therein and exhibits electric conductivity. In dynamic light scattering analysis, the average diameter of rGO composites before and after reduction changed slightly from 419 ± 309 to 663 ± 697 nm, indicating that the chemical reduction is not significantly influenced by the size of the rGO composite or the solubility. It is expected that the soft wrapping cPor-Fe/rGO should employ the applications to prepare functional materials such as modified electrodes, catalysts, energy-storage materials, and electronic devices.

A method for the protecting group free synthesis of β-urea-linked glycoconjugates has been developed. The one step process, involving reactions between urea and D-glucose, N-acetyl-D-glucosamine or D-xylose in acidic aqueous solution, furnishes the corresponding β-urea glycosides in modest yields. This simple and efficient procedure is applicable to the synthesis of β-urea tethered amino acid-carbohydrate conjugates.

Solar flares are caused by the sudden release of magnetic energy stored near sunspots. They release 10(29) to 10(32) ergs of energy on a timescale of hours. Similar flares have been observed on many stars, with larger 'superflares' seen on a variety of stars, some of which are rapidly rotating and some of which are of ordinary solar type. The small number of superflares observed on solar-type stars has hitherto precluded a detailed study of them. Here we report observations of 365 superflares, including some from slowly rotating solar-type stars, from about 83,000 stars observed over 120 days. Quasi-periodic brightness modulations observed in the solar-type stars suggest that they have much larger starspots than does the Sun. The maximum energy of the flare is not correlated with the stellar rotation period, but the data suggest that superflares occur more frequently on rapidly rotating stars. It has been proposed that hot Jupiters may be important in the generation of superflares on solar-type stars, but none have been discovered around the stars that we have studied, indicating that hot Jupiters associated with superflares are rare.

The first total synthesis of amino sugar antibiotic glycocinnasperimicin D (1) has been achieved by a convergent, three-component coupling strategy. The key steps involve the Heck-Mizoroki reaction by using the iodophenyl glycoside 50 and acryl amide 32 to furnish the right core structure of 1, and the construction of the urea glycoside employing the reaction of glycosyl isocyanate 8 with amino sugar 9. Glycosyl isocyanate 8 was prepared by the oxidation of isonitrile 10, which displayed excellent reactivity in the coupling event. Synthetic roadblocks, encountered during this synthetic effort, have led to the development of the alpha-selective, Lewis acid catalyzed phenyl glycosylation process with 2-amino-hexopyranose and a procedure for acetonide deprotection without affecting the silyl ethers.

Lettuce big-vein virus (LBVV) is the type species of the genus Varicosavirus and is a two-segmented negative-sense single-stranded RNA virus. The larger LBVV genome segment (RNA1) consists of 6797 nt and encodes an L polymerase that resembles that of rhabdoviruses. Here, the nucleotide sequence of the second LBVV genome segment (RNA2) is reported. LBVV RNA2 consisted of 6081 nt and contained antisense information for five major ORFs: ORF1 (nt 210-1403 on the viral RNA), ORF2 (nt 1493-2494), ORF3 (nt 2617-3489), ORF4 (nt 3843-4337) and ORF5 (nt 4530-5636), which had coding capacities of 44, 36, 32, 19 and 41 kDa, respectively. The gene at the 3' end of the viral RNA encoded a coat protein, while the other four genes encoded proteins of unknown functions. The 3'-terminal 11 nt of LBVV RNA2 were identical to those of LBVV RNA1, and the 5'-terminal regions of LBVV RNA1 and RNA2 contained a long common nucleotide stretch of about 100 nt. Northern blot analysis using probes specific to the individual ORFs revealed that LBVV transcribes monocistronic RNAs. Analysis of the terminal sequences, and primer extension and RNase H digestion analysis of LBVV mRNAs, suggested that LBVV utilizes a transcription termination/initiation strategy comparable with that of rhabdoviruses.