Thermal decomposition study of bismuth (III) trichloride complex with 1,10-phenanthroline as the ligand

The complex BiCl₃·L (L = 1,10-phenanthroline) was synthesized and characterized by elemental analysis and infrared spectroscopy (IR). Infrared spectroscopy data suggested that the nitrogen atom of the aromatic ring is bonded to the bismuth atom. The kinetic study of thermal degradation was determined by non-isothermal thermogravimetry. Two methods based on integral equation of Coats-Redfern, were necessary for determining the kinetic trip: the fitting method, known as the checking model and an iso-conversional method. The latter gives the activation energy for each degree of conversion and the first, the kinetic model gives activation energy and the pre-exponential factor for thermal decomposition processes that occur through a single simple mechanism. The kinetic parameters, E _a and log A for the heating rates of 5, 10, and 15 min K⁻¹, were determined considering the decomposition model denoted by F0/R1 in the range of degree of conversion between 0.065 and 0.71.     

Lossless single-photon shaping via heralding

Using spontaneous optical parametric downconversion, we experimentally demonstrate heralded generation of shaped single photons, whose modes are tailored indirectly by applying amplitude modulation on the pump field that drives the downconversion process. Our experiment opens a door to creating high-quality, mode-shaped single photons at a substantially higher efficiency than is possible with the existing method of direct single-photon shaping.     

Small-angle X-ray scattering and structural modeling of full-length: cellobiohydrolase I from Trichoderma harzianum

Cellobiohydrolases hydrolyze cellulose releasing cellobiose units. They are very important for a number of biotechnological applications, such as, for example, production of cellulosic ethanol and cotton fiber processing. The Trichoderma cellobiohydrolase I (CBH1 or Cel7A) is an industrially important exocellulase. It exhibits a typical two domain architecture, with a small C-terminal cellulose-binding domain and a large N-terminal catalytic core domain, connected by an O-glycosylated linker peptide. The mechanism by which the linker mediates the concerted action of the two domains remains a conundrum. Here, we probe the protein shape and domain organization of the CBH1 of Trichoderma harzianum (ThCel7A) by small angle X-ray scattering (SAXS) and structural modeling. Our SAXS data shows that ThCel7A linker is partially-extended in solution. Structural modeling suggests that this linker conformation is stabilized by inter- and intra-molecular interactions involving the linker peptide and its O-glycosylations.     

Deep investigation on inorganic fraction of atmospheric PM in Mediterranean area by neutron and photon activation analysis

Background

Anthropogenic activities introduce materials increasing levels of many dangerous substances for the environmental quality and being hazardous to human health. Major attention has been given to those elements able to alter the environment and endanger human health.The airborne particulate matter pollutant is considered one of the most difficult task in environmental chemistry for its complex composition and implications complicating notably the behavior comprehension. So, for investigating deeply the elemental composition we used two nuclear techniques, Neutron Activation Analysis and Photon Activation Analysis, characterized by high sensitivity, precision and accuracy. An important task has been devoted to the investigation of Quality Control (QC) and Quality Assurance (QA) of the methodology used in this study.This study was therefore extended as far back as possible in time (from 1965 until 2000) in order to analyze the trend of airborne concentration of pollutant elements in connection with the industrial and lifestyle growth during the entire period.

Results

Almost all the elements may be attributed to long-range transport phenomena from other natural and/or anthropogenic sources: this behavior is common to all the periods studied even if a very light decreasing trend can be evidenced from 1970 to 2002. Finally, in order to investigate a retrospective study of elements in PM10 and their evolution in relationship with the natural or anthropogenic origins, we have investigated the Enrichment Factors. The study shows the EF trends for some elements in PM10 during four decades.

Conclusions

The two nuclear techniques have allowed to reach elevated sensibility/accuracy levels for determining elements at very low concentrations (trace and ultra-trace levels). The element concentrations determined in this study do not basically show a significant level of attention from a toxicological point of view.

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A multistage linear stochastic programming model for optimal corporate debt management

Large corporations fund their capital and operational expenses by issuing bonds with a variety of indexations, denominations, maturities and amortization schedules. We propose a multistage linear stochastic programming model that optimizes bond issuance by minimizing the mean funding cost while keeping leverage under control and insolvency risk at an acceptable level. The funding requirements are determined by a fixed investment schedule with uncertain cash flows. Candidate bonds are described in a detailed and realistic manner. A specific scenario tree structure guarantees computational tractability even for long horizon problems. Based on a simplified example, we present a sensitivity analysis of the first stage solution and the stochastic efficient frontier of the mean-risk trade-off. A realistic exercise stresses the importance of controlling leverage. Based on the proposed model, a financial planning tool has been implemented and deployed for Brazilian oil company Petrobras.     

On compact extensions of multilinear operators

In this paper we prove that, under certain conditions, Nicodemi extensions of compact multilinear operators between Banach spaces are compact as well. An application of this result to the isometric/isomorphic theory of spaces of compact multilinear operators is provided.     

利用一个通用的方法全合成Fuscinarin和Fuscins

通过一个共同的中间体6,首次全合成了fuscinarin (1)和全合成了fuscins,它们都是戊烯酮(pentaketide)的代谢物,在亲近闪烁检测(scintillation proximity assay)中显示具有抗CCR5的活性。这一合成主要是利用微波辅助的 ortho-Claisen/Cope 重排的串联反应更合成中间体10。     

VO2热致变色薄膜的结构和光电特性研究

用磁控溅射方法制备了VO₂热致变色薄膜.用X射线衍射、X射线光电子谱和原子力显微镜对薄膜的宏观及微观结构进行了分析，表明VO₂薄膜纯度高、相结构单一、结晶度好.薄膜的光透过率在2000nm处相变前后改变了42%，高/低温电阻率变化达到三个数量级以上.薄膜的光透过谱和相变过程中电学性质变化的研究与结构分析结果相一致. 关键词：     

The H + Li2 bimolecular exchange reaction: dynamical and kinetical properties at J = 0

For the first time in the literature, rigorous time-independent quantum scattering formalism was applied, by means of the ABC program, to the H + Li(2) → LiH + Li reaction. The state-to-state probabilities as a function of the total energy have been computed at zero total angular momentum (J = 0) allowing us to evaluate the effect of vibrational/rotational excitation on the reaction promotion/inhibition, the energetic distribution of products, and the temperature dependence of the J-shifting thermal rate coefficients.     

Effects of solvent polarity on mutual styrene grafting onto polypropylene by electron beam irradiation

Radiation induced mutual grafting of styrene onto polypropylene has been carried using several grafting solutions with different organic solvents and polarity levels. In the mixture of styrene and protic polar solvents high grafting yields were obtained. This behavior suggests that grafting process does not have dependence on swelling of the substrate, something that is expected when a non-polar substrate and a non-polar media are in contact. In this case, the grafting yield may be related to the free radical generation at protic polar solvent; these reactive specimens start the reaction on substrate surface to allow the accessibility of monomer species to active sites. Some reaction mechanisms are proposed.