Phosphinated polydiacetylene. Its preparation and use for support of rhodium complex catalyst

The reaction of poly(1,6-bis(p-toluene sulfonate)-2,4-hexadiyne) with lithiodiphenylphosphine gives a phosphinated polymer of a stiff chain. Complexation of the polymer with [RhCl(C₈H₁₄)₂]₂ (C₈H₁₄=cyclooctene) affords an active catalyst for the hydrogenation of conjugated olefins. Some properties of the polymer-bound rhodium complexes are described.     

Higher order operator splitting methods via Zassenhaus product formula: Theory and applications

In this paper, we contribute higher order operator splitting methods improved by Zassenhaus product. We apply the contribution to classical and iterative splitting methods. The underlying analysis to obtain higher order operator splitting methods is presented. While applying the methods to partial differential equations, the benefits of balancing time and spatial scales are discussed to accelerate the methods.The verification of the improved splitting methods are done with numerical examples. An individual handling of each operator with adapted standard higher order time-integrators is discussed. Finally, we conclude the higher order operator splitting methods.     

Letter to the Editor

Social policy is concerned with the integration of values, the principles by which these values are translated into policies and programs, assessments of the outcomes of implementing these principles in terms of the values asserted, and the search for strategies of feasible change which promise a better fit between values, principles, and outcomes. One aspect without the others is not policy analysis. Yet, current efforts have failed to integrate effectively these tasks, thus raising questions about whether social policy is a legitimate discipline. Rather than prematurely forcing a grand synthesis, this article tries to extend our understanding of the often partisan nature of policy analysis. Specifically, it illustrates how beliefs intrude at each level of analysis—in definitions of the purposes of policy, in the priorities assigned, in the institutional forms which translate beliefs to programs, in the evaluation of outcomes, and in assessments of what changes are politically feasible. The conclusion that there is no one true policy analysis frustrates the development of an independent discipline, but suggests a stance that analysts of policy might follow.     

Proteomics and Leishmaniasis: Potential Clinical Applications

Leishmaniases are diseases caused by protozoan parasites of the genus Leishmania. They are endemic in 98 countries, affect around 12 million people worldwide and may present several distinct clinical forms. Unfortunately, there are only a few drugs available for treatment of leishmaniasis, which are toxic and not always effective. Different parasite species and different clinical forms require optimization of the treatment or more specific therapies, which are not available. The emergence of resistance is also a matter of concern. Besides, diagnosis can sometimes be complicated due to atypical manifestations and associations with other pathologies. In this review, proteomic data are presented and discussed in terms of their application in important issues in leishmaniasis such as parasite resistance to chemotherapy, diagnosis of active disease in patients and dogs, markers for different clinical forms, identification of virulence factors, and their potential use in vaccination. It is shown that proteomics has contributed to the discovery of potential biomarkers for prognosis, diagnosis, therapeutics, monitoring of disease progression, treatment follow‐up and identification of vaccine candidates for specific diseases. However, the authors believe its capabilities have not yet been fully explored for routine clinical analysis for several reasons, which will be presented in this review.     

Evaluation of a Method for Measurement of the Concentration and Size Distribution of Black Carbon Particles Suspended in Rainwater

We make detailed evaluations of a method of measuring the mass concentration and size distribution of black carbon (BC) particles suspended in water for the purpose of application to rainwater samples. Water samples were aerosolized with an ultrasonic nebulizer. Generated water droplets were dried in order to extract airborne BC particles. The mass of each BC particle was then measured by a Single Particle Soot Photometer (SP2), based on the laser-induced incandescence technique. Under the optimized operating conditions of our measurement system, the overall efficiency of the extraction of BC particles from rainwater was determined to be 11.4% ± 0.83% by mass, resulting in a total uncertainty of about ±20% for the measurement of the BC concentration in rainwater. The change in efficiency due to water-soluble species was found to be negligibly small for rainwater samples analyzed in this study. The determination of the efficiency by using standard BC solutions was necessary at an appropriate frequency because changes in the overall conditions of the system lead to changes in the efficiency in the long term. The size of BC particles in rainwater can be overestimated because of the coagulation of BC particles in the process of extraction by the nebulizer. This effect increased with the increase in BC concentration in rainwater. The effect can be minimized by dilution of rainwater samples by pure water. The volume of a rainwater sample required for BC measurement was less than 5 mL, enabling measurement for weak rain or highly time-resolved measurements during each rain event.     

Crystal structure and methane oxidation on perovskite-type (La<Subscript>1−<Emphasis Type="Italic">x</Emphasis></Subscript>Nd<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>)CoO<Subscript>3</Subscript> synthesized using citric acid

Perovskite-type (La_1−x Nd _x )CoO₃ was synthesized using citric acid at 700 °C. The Rietveld method indicated that the crystal structure changed from a rhombohedral to an orthorhombic system at x = 0.4. The Co–O distance of the rhombohedral structure connected continuously with the average Co–O(2) distance of the orthorhombic structure, and the Co–O–Co angle of the rhombohedral structure and the Co–O(2)–Co angle of the orthorhombic structure were continuous. The average particle size of the samples was approximately 55 nm. CH₄ oxidation started above 300 °C, and the temperature corresponding to the 50% conversion (T _1/2) of CH₄ increased linearly with increases in x. It is considered that the amount of adsorbed oxygen decreased in response to the steric hindrance, and that T _1/2 increased as a result.     

Near-band-edge photoluminescnce in Cu(In,Ga)Se2 solar cells

Photoluminescence (PL) and PL decay characteristics of the near-band-edge (NBE) PL at room temperature have been studied on the Cu(In,Ga)Se₂ (CIGS) solar cells. The carrier recombination process has been discussed with emphasis on the photovoltaic properties of the solar cell. It has been found that: (i) PL intensity of the CIGS solar cells is much stronger than that in the corresponding CIGS thin films, (ii) the PL decay time of the cell is longer than that of the CIGS film, and (iii) the PL decay time of the CIGS solar cell exhibits strong dependence on the PL excitation intensity. In the CIGS solar cell, intense PL is obtained under the open circuit condition (oc), in contrast to the very low PL yield under the short circuit (sc) condition. The PL decay time under the sc condition is much shorter than that under the oc condition. Excitation intensity dependence of PL intensity and the PL decay time have been studied, and they are discussed with relation to the photo-voltage due to the PL excitation light. PL and injection EL under the external DC bias have been studied. The mapping image of NBE-PL intensity has been compared with that of the laser beam induced current (LBIC), and the PL intensity image reflects the photovoltaic properties of the CIGS solar cells. We demonstrated that NBE-PL of the CIGS solar cell reflects the photovoltaic effect, and it can be utilized as a powerful characterization method.     

Toward Precision Measurement and Manipulation of Single‐Molecule Reactions by a Confined Space

All chemical reactions can be divided into a series of single molecule reactions (SMRs), the elementary steps that involve only isomerization of, dissociation from, and addition to an individual molecule. Analyzing SMRs is of paramount importance to identify the intrinsic molecular mechanism of a complex chemical reaction, which is otherwise implausible to reveal in an ensemble fashion, owing to the significant static and dynamic heterogeneity of real‐world chemical systems. The single‐molecule measurement and manipulation methods developed recently are playing an increasingly irreplaceable role to detect and recognize short‐lived intermediates, visualize their transient existence, and determinate the kinetics and dynamics of single bond breaking and formation. Notably, none of the above SMRs characterizations can be realized without the aid of a confined space. Therefore, this Review aims to highlight the recent progress in the development of confined space enabled single‐molecule sensing, imaging, and tuning methods to study chemical reactions. Future prospects of SMRs research are also included, including a push toward the physical limit on transduction of information to signals and vice versa, transmission and recording of signals, computational modeling and simulation, and rational design of a confined space for precise SMRs.