Catalytic Activities of Alcohol Transformations Over 8-Ring Zeolites

Aluminosilicate H/CHA and H/MTF zeolites show remarkably different catalytic activities in the methanol and ethanol transformations although they have similar pore size of 8-membered ring structures. Moreover, the produced ethylene is further converted on H/CHA, but H/MTF is not active for the ethylene transformation. The correlations between the distinct catalytic differences and their intrinsic structural properties, including topology and acidity, are discussed.     

激光诱发光致发光光谱分析在宝石学中的应用——以钻石为例

确定钻石的颜色成因如今已变得越来越重要. 事实上相似颜色的钻石有不同的颜色成因, 如天然的、辐照的、 HPHT处理的或合成的. 借助拉曼显微镜Renishaw Ramanscope System 100B和用514 nm的Ar激光作激发源, 用液氮在-150℃条件下对钻石进行测定, 来研究激光诱发光致发光分析用于确定钻石颜色成因的可靠性.     

Oxidative Dehydrogenation of Propane with CO2 Over Cr/H[B]MFI Catalysts

Abstract  

Cr/silicalite-1 and Cr/H[B]MFI catalysts were prepared by the impregnation method, and Cr/H[B]MFI were further treated by steaming. The catalysts were employed for the oxidative dehydrogenation of propane to propylene with CO₂ as the oxidant. Cr/H[B]MFI showed significantly higher catalytic activity than Cr/silicalite-1, and steamed Cr/H[B]MFI was superior in the reaction stability to Cr/H[B]MFI. The nature of the supported chromium species have been characterized by a number of physicochemical techniques, such as Raman, UV–vis and NMR. It is concluded that the steaming led to the auto-reduction of some Cr⁶⁺ to Cr³⁺, and resultant Cr³⁺ species might be located near the boron center in the borosilicate framework to counterbalance the negative charge of the framework. The transformation of Cr⁶⁺ species to Cr³⁺ species, facilitated by the steaming process and the presence of boron in the catalyst, is responsible for the enhanced stability of oxidative dehydrogenation of propane to propylene with carbon dioxide as the oxidant.     

Reliabilities and concurrent validities of popular self-report measures of depression, anxiety, and social desirability.

135 male and 256 female undergraduates completed the Self-Rating Depression Scale, Beck Depression Inventory, Depression Adjective Check Lists, State-Trait Anxiety Inventory, Taylor Manifest Anxiety Scale, S-R Inventory of Anxiousness, Marlowe-Crowne Social Desirability Scale, and Edwards Social Desirability Scale. Pearson correlation coefficients indicated strong relationships between measures of depression and between measures of anxiety. However, pairs of anxiety and depression measures correlated almost as strongly. All depression and anxiety measures were significantly associated with the Edwards Social Desirability Scale. Findings question the use of a self-report measure of depression to select "depressed" Ss among college students. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

One-Dimensional Phonon State of 4He Films Adsorbed in Straight Nanopores

We have studied heat capacities of ⁴He adsorbed in straight nanopores 1.8, 2.2, and 2.8 nm in diameter. Heat capacities of the ⁴He fluid film on the solid layer at 0.08–0.4 K show power laws close to T in 1.8 nm pores, close to T ² in 2.8 nm pores, and a crossover from T to T ² with increasing temperature in 2.2 nm pores. These heat capacities are explained by a model assuming a phonon dispersion with continuous one-dimensional (1D) states in the axial direction and discrete energy levels in the azimuthal direction. By fitting experimental data to the model, the phonon velocity along the pore axis and the energy gap for propagation in the cross section are derived. At temperatures sufficiently lower than the energy gap, where the thermal wave length of phonons is much longer than the effective pore diameter, the ⁴He fluid films show a T-linear heat capacity of 1D phonons propagating only along the pore axis. At higher temperatures, a 1D-2D crossover of phonons occurs.      

Indoor and outdoor concentrations of Japanese cedar pollens and total suspended particulates: A case study at a kindergarten in Japan

Japanese cedar pollinosis (JCP) caused by allergenic cedar and cypress pollens is one of major economic and health issues in Japan. The present study reported here aimed to provide basic data to understand the status of early life exposures to airborne cedar and cypress pollens in school settings. In particular, the study investigated relationships between indoor and outdoor concentrations of airborne cedar and cypress pollens and total suspended particulates (TSP) in a kindergarten in Japan. Overall, outdoor concentrations of the airborne pollens and TSP were higher than the indoor concentrations, i.e., indoor to outdoor (I/O) ratios of 0.043–0.055 and 0.545 for the airborne pollens and TSP, respectively. The smaller I/O ratios for the pollens were expected because the larger pollen grains (20–30 μm in diameter) were less likely penetrated to indoor environment than for smaller airborne particulates. The present study also found increased TSP concentrations during the pollen season was likely attributed to increased airborne pollen concentrations. By understanding the status of indoor and outdoor concentrations of airborne cedar and cypress pollens in school settings, early life exposures to these allergenic pollens should be effectively minimized to prevent subsequent progression to JCP symptoms.     

Relative reactivity of phenylboronic acid to phenylboronate ion toward L-lactate and mandelate at physiological pH

Kinetic studies were performed on the reactions of phenylboronic acid with L-lactic acid and mandelic acid in acidic aqueous and alkaline solutions in order to specify reactive species in these reactions. It was confirmed that the diprotonated ligand (H₂L: L-lactic acid or mandelic acid) is less reactive than the monoprotonated ligand (HL^?: L-lactate ion or mandelate ion), which made possible direct determination of the rate constants of phenylboronic acid (PhB(OH)₂) and its conjugate base, phenylboronate ion (PhB(OH)₃^?). It was found that PhB(OH)₂ is more reactive than PhB(OH)₃^?. On the basis of kinetic results, it was concluded that the most reactive species are PhB(OH)₂ and HL^? at physiological pH 7.4, so the reaction in the boronic acid-based sensor for L-lactate mainly would occur between these species.     

Ultra Low-Dose Radiation: Stress Responses and Impacts Using Rice as a Grass Model

We report molecular changes in leaves of rice plants (Oryza sativa L. - reference crop plant and grass model) exposed to ultra low-dose ionizing radiation, first using contaminated soil from the exclusion zone around Chernobyl reactor site. Results revealed induction of stress-related marker genes (Northern blot) and secondary metabolites (LC-MS/MS) in irradiated leaf segments over appropriate control. Second, employing the same in vitro model system, we replicated results of the first experiment using in-house fabricated sources of ultra low-dose gamma (γ) rays and selected marker genes by RT-PCR. Results suggest the usefulness of the rice model in studying ultra low-dose radiation response/s.