Main chain and segmental dynamics of semi interpenetrating based on polyisoprene and poly(methyl methacrylate)

Main chain and segmental dynamics of polyisoprene (PI) and poly(methyl methacrylate)(PMMA) chains in semi IPNs were systematically studied over a wide range of temperatures (above and below T-g of both polymers) as a function of composition, crosslink density, and molecular weight. The immiscible polymers retained most of its characteristic molecular motion; however, the semi IPN synthesis resulted in dramatic changes in the motional behavior of both polymers due to the molecular level interpenetration between two polymer chains. ESR spin probe method was found to be sensitive to the concentration changes of PMMA in semi IPNs. Low temperature spectra showed the characteristics of rigid limit spectra, and in the range of 293-373 K.complex spectra were obtained with the slow component mostly arisingout of the PMMA rich regions and fast component from the PI phase. We found that the rigid PMMA chains closely interpenetrated into thehighly mobile PI network imparts motional restriction in nearby PI chains, and the highly mobile PI chains induce some degree of flexibility in highly rigid PMMA chains. Molecular level interchain mixing was found to be more efficient at a PMMA concentration of 35 wt.%. Moreover, the strong interphase formed in the above mentionedsemi IPN contributed to the large slow component in the ESR spectra at higher temperature. The shape of the spectra along with the data obtained from the simulations of spectra was correlated to the morphology of the semi IPNs. The correlation time measurement detected the motional region associated with the glass transition of PI and PMMA, and these regions were found to follow the same pattern of shifts in a-relaxation of PI and PMMA observed in DMA analysis. Activation energies associated with the T-g regions were also calculated. T-50G was found to correlate with the T-g of PMMA, and the volume of polymer segments undergoing glass transitional motion was calculated to be 1.7 nm(3).C-13 T-1 rho measurements of PMMA carbons indicate that the molecular level interactions were strong in semi IPN irrespective of the immiscible nature of polymers. The motional characteristics of H atoms attached to carbon atoms in both polymers were analyzed using 2D WISE NMR. Main relaxations of both components shifted inward, and both SEM and TEM analysis showed the development of a nanometer sized morphology in the case of highly crosslinked semi IPN. (C) 2010 Elsevier Ltd. All rights reserved.

Synthetic investigations in the sesamin group - Part I. Synthesis of samin, a degradation product of sesamolin

Ethylα-bromovinylacetate (VII) was condensed with the sodio derivative of ethyl piperonoylacetate (VIII) to give diethylα-vinyl-α′-piperonoylsuccinate (IX). The latter on reduction with lithium aluminium hydride furnished the triol (X), which underwent smooth cyclisation with 1% ethanolic hydrogen chloride to 2-(3′, -methylenedioxyphenyl)-hydroxymethyl-4-vinyltetrahydrofuran (XIa). The structure of XIa was established by Oppenauer oxidation to an aldehyde. Ozonolysis of XIa afforded samin (I).

Direct Measurement of the W Production Charge Asymmetry in pp̅ Collisions at √s=1.96 TeV

We present the first direct measurement of the $W$ production charge asymmetry as a function of the $W$ boson rapidity $\yW$ in $\ppbar$ collisions at $\sqrt{s} = 1.96$ $\TeV$. We use a sample of $\wenu$ events in data from 1 $\ifb$ of integrated luminosity collected using the CDF II detector. In the region $|\yW|

The interaction of glycoxylate with cysteine and its application to the assay of isocitritase and of transaminases involving glyoxylate

An interesting interaction between glyoxylate and cystein takes place in phosphate buffer (pH 7.0) to form a product which is resistant to hydrolysis at ordinary temperatures. The reaction product is broken up by acid hydrolysis at elevated temperatures under controlled conditions, giving a quantitive yield of glyoxylate. Other keto acids, such as α-ketoglutarate, pyruvate and oxaloacetate, do not interact with cysteine under similar conditions. Methods based on these findings are described for(a) direct estimation of other keto acids in the presence of glyoxylate, and (b) assay of isocitritase and glyoxylate transaminase.

Synthesis of 1,3-dimethyl-1,3-dicarboxycyclohexane-2-acetic acid. An isomer of the degradation product of abietic acid

A synthesis of 1,3-dimethyl-1,3-dicarboxycyclohexane-2-acetic acid has been described, and proved to be an isomer of the C12-acid-an oxidative degradation product of abietic acid.

Reaction of dialkyl 2-butynoate with aniline and formaldehyde: revision of the structure of the product

Dimethyl 3-(aryl)-3,6-dihydro-2H-1,3-oxazine4,5-dicarboxylate structure assigned for the products obtained in the Bronsted acid catalyzed reaction of dimethyl but-2-ynoates with anilines and an excess of formaldehyde in methanol has been revised to methyl 1-(aryl)-3-(methoxymethyl)-4,5-dioxopyrrolidine-3-carboxylate. (C) 2010 Elsevier Ltd. All rights reserved.

Consumption in Rural Bangladesh : Households, Lifestyles, and Identities

Bangladesh, often better known to the outside world as a country of natural calamities, is one of the most densely populated countries in the world. Despite rapid urbanization, more than 75% of the people still live in rural areas. The density of the rural population is also one of the highest in the world. Being a poor and low-income country, its main challenge is to eradicate poverty through increasing equitable income. Since its independence in 1971, Bangladesh has experienced many ups and downs, but over the past three decades, its gross domestic product (GDP) has grown at an impressive rate. Consequently, the country s economy is developing and the country has outperformed many low-income countries in terms of several social indicators. Bangladesh has achieved the Millennium Development Goal (MDG) of eliminating gender disparity in primary and secondary school enrollment. A sharp decline in child and infant mortality rates, increased per capita income, and improved food security have placed Bangladesh on the track to achieving in the near future the status of a middle-income country. All these developments have influenced the consumption pattern of the country. This study explores the consumption scenario of rural Bangladesh, its changing consumption patterns, the relationship between technology and consumption in rural Bangladesh, cultural consumption in rural Bangladesh, and the myriad reasons why consumers nevertheless feel compelled to consume chemically treated foods. Data were collected in two phases in the summers of 2006 and 2008. In 2006, the empirical data were collected from the following three sources: interviews with consumers, producers/sellers, and doctors and pharmacists; observations of sellers/producers; and reviews of articles published in the national English and Bengali (the national language of Bangladesh) daily newspapers. A total of 110 consumers, 25 sellers/producers, 7 doctors, and 7 pharmacists were interviewed and observed. In 2008, data were collected through semi-structured in-depth qualitative interviews, ethnography, and unstructured conversations substantiated by secondary sources and photographs; the total number of persons interviewed was 22. -- Data were also collected on the consumption of food, clothing, housing, education, medical facilities, marriage and dowry, the division of labor, household decision making, different festivals such as Eid (for Muslims), the Bengali New Year, and Durga puja (for Hindus), and leisure. Qualitative methods were applied to the data analysis and were supported by secondary quantitative data. The findings of this study suggest that the consumption patterns of rural Bangladeshis are changing over time along with economic and social development, and that technology has rendered aspects of daily life more convenient. This study identified the perceptions and experiences of rural people regarding technologies in use and explored how culture is associated with consumption. This study identified the reasons behind the use of hazardous chemicals (e.g. calcium carbide, sodium cyclamate, cyanide and formalin, etc.) in foods as well as the extent to which food producers/sellers used such chemicals. In addition, this study assessed consumer perceptions of and attitudes toward these contaminated food items and explored how adulterated foods and food stuffs affect consumer health. This study also showed that consumers were aware that various foods and food stuffs contained hazardous chemicals, and that these adulterated foods and food stuffs were harmful to their health.

ISO 13567 - The Proposed International Standard for Structuring Layers in Computer Aided Building Design

Layering is a widely used method for structuring data in CAD-models. During the last few years national standardisation organisations, professional associations, user groups for particular CAD-systems, individual companies etc. have issued numerous standards and guidelines for the naming and structuring of layers in building design. In order to increase the integration of CAD data in the industry as a whole ISO recently decided to define an international standard for layer usage. The resulting standard proposal, ISO 13567, is a rather complex framework standard which strives to be more of a union than the least common denominator of the capabilities of existing guidelines. A number of principles have been followed in the design of the proposal. The first one is the separation of the conceptual organisation of information (semantics) from the way this information is coded (syntax). The second one is orthogonality - the fact that many ways of classifying information are independent of each other and can be applied in combinations. The third overriding principle is the reuse of existing national or international standards whenever appropriate. The fourth principle allows users to apply well-defined subsets of the overall superset of possible layernames. This article describes the semantic organisation of the standard proposal as well as its default syntax. Important information categories deal with the party responsible for the information, the type of building element shown, whether a layer contains the direct graphical description of a building part or additional information needed in an output drawing etc. Non-mandatory information categories facilitate the structuring of information in rebuilding projects, use of layers for spatial grouping in large multi-storey projects, and storing multiple representations intended for different drawing scales in the same model. Pilot testing of ISO 13567 is currently being carried out in a number of countries which have been involved in the definition of the standard. In the article two implementations, which have been carried out independently in Sweden and Finland, are described. The article concludes with a discussion of the benefits and possible drawbacks of the standard. Incremental development within the industry, (where ”best practice” can become ”common practice” via a standard such as ISO 13567), is contrasted with the more idealistic scenario of building product models. The relationship between CAD-layering, document management product modelling and building element classification is also discussed.

A semi-classical model of the electron containing tachyonic matter

It is shown that the mass of the electron could be conceived as the energy associated with its spinning motion and the angular velocity is such that the linear velocities at the surface exceed the velocity of light; this in fact accounts for its stability against the centrifugal forces in the core region.

A new ELISA plate based microtiter well assay for mycobacterial topoisomerase I for the direct screening of enzyme inhibitory monoclonal antibody supernatants

Antigen specific monoclonal antibodies present in crude hybridoma supernatants are normally screened by ELISA on plates coated with the relevant antigen. Screening for inhibitory monoclonals to enzymes would require the evaluation of purified antibodies or antibody containing supernatants for their inhibition of enzyme activity in a separate assay. However, screening for inhibitory antibodies against DNA transacting enzymes such as topoisomerase I (topo I) cannot be done using hybridoma supernatants due to the presence of nucleases in tissue culture media containing foetal calf serum which degrade the DNA substrates upon addition. We have developed a simple and rapid screening procedure for the identification of clones that secrete inhibitory antibodies against mycobacterial topo I using 96 well ELISA microtiter plates. The principle of the method is the selective capture of monoclonal antibodies from crude hybridoma supernatants by topo I that is tethered to the plate through the use of plate-bound polyclonal anti-topo I antibodies. This step allows the nucleases present in the medium to be washed off leaving the inhibitor bound to the tethered enzyme. The inhibitory activity of the captured antibody is assessed by performing an in situ DNA relaxation assay by the addition of supercoiled DNA substrate directly to the microtiter well followed by the analysis of the reaction products by agarose gel electrophoresis. The validity of this method was confirmed by purification of the identified inhibitory antibody and its evaluation in a DNA relaxation assay. Elimination of all enzyme-inhibitory constituents of the culture medium from the well in which the inhibitory antibody is bound to the tethered enzyme may make this method broadly applicable to enzymes such as DNA gyrases, restriction enzymes and other DNA transaction enzymes. Further, the method is simple and avoids the need of prior antibody purification for testing its inhibitory activity. (C) 2010 Elsevier B.V. All rights reserved.

Electro-Oxidation of Borohydride on Rhodium, Iridium, and Rhodium-Iridium Bimetallic Nanoparticles with Implications to Direct Borohydride Fuel Cells

Electrochemical oxidation of borohydride is studied on nanosized rhodium, iridium, and bimetallic rhodium-iridium catalysts supported onto Vulcan XC72R carbon. The catalysts are characterized by X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy in conjunction with cyclic voltammetry and polarization studies. The studies reveal that a 20 wt % bimetallic Rh-Ir catalyst supported onto carbon (Rh-Ir/C) is quite effective for the oxidation of borohydride. Direct borohydride fuel cell with Rh-Ir/C as the anode catalyst and Pt/C as the cathode catalyst exhibits a peak power density of 270 mW/cm(2) at a load current density of 290 mA/cm(2) as against 200 mW/cm(2) at 225 mA/cm(2) for Rh/C and 140 mW/cm(2) at 165 mA/cm(2) for Ir/C while operating at 80 degrees C. The synergistic catalytic activity for the bimetallic Rh-Ir nanoparticles toward borohydride oxidation is corroborated by density-functional theory calculations using electron-localization function. (C) 2010 The Electrochemical Society. [DOI:10.1149/1.3442372] All rights reserved.

Direct Synthesis of Terminally ``Clickable'' Linear and Hyperbranched Polyesters

1,3-Dipolar cycloaddition of an organic azide and an acetylenic unit,often referred to as the ``click reaction'', has become an important ligation tool both in the context of materials chemistry and biology. Thus, development of simple approaches to directly generate polymers that bear either an azide or an alkyne unit has gained considerable importance. We describe here a straightforward approach to directly prepare linear and hyperbranched polyesters that carry terminal propargyl groups. To achieve the former, we designed an AB-type monomer that carries a hydroxyl group and a propargyl ester, which upon self-condensation under standard transesterification conditions yielded a polyester that carries a single propargyl group at one of its chain-ends. Similarly, an AB(2) type monomer that carries one hydroxyl group and two propargyl ester groups, when polymerized under the same conditions yielded a hyperbranched polymer with numerous clickable'' propargyl groups at its molecular periphery. These propargyl groups can be readily clicked with different organic azides, such as benzyl azide, omega-azido heptaethyleneglycol monomethylether or 9-azidomethyl anthracene. When an anthracene chromophore is clicked, the molecular weight of the linear polyester could be readily estimated using both UV-visible and fluorescence spectroscopic measurements. Furthermore, the reactive propargyl end group could also provide an opportunity to prepare block copolymers in the case of linear polyesters and to generate nanodimensional scaffolds to anchor variety of functional units, in the case of the hyperbranched polymer. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3200-3208, 2010.