Spatial correlation in grain misorientation distribution

Grain misorientation was studied in relation to the nearest neighbor's mutual distance using electron back-scattered diffraction measurements. The misorientation correlation function was defined as the probability density for the occurrence of a certain misorientation between pairs of grains separated by a certain distance. Scale-invariant spatial correlation between neighbor grains was manifested by a power law dependence of the preferred misorientation vs. inter-granular distance in various materials after diverse strain paths. The obtained negative scaling exponents were in the range of -2 +/- 0.3 for high-angle grain boundaries. The exponent decreased in the presence of low-angle grain boundaries or dynamic recrystallization, indicating faster decay of correlations. The correlations vanished in annealed materials. The results were interpreted in terms of lattice incompatibility and continuity conditions at the interface between neighboring grains. Grain-size effects on texture development, as well as the implications of such spatial correlations on texture modeling, were discussed.

Entire Solutions of Hydrodynamical Equations with Exponential Dissipation

We consider a modification of the three-dimensional Navier-Stokes equations and other hydrodynamical evolution equations with space-periodic initial conditions in which the usual Laplacian of the dissipation operator is replaced by an operator whose Fourier symbol grows exponentially as e(vertical bar k vertical bar/kd) at high wavenumbers vertical bar k vertical bar. Using estimates in suitable classes of analytic functions, we show that the solutions with initially finite energy become immediately entire in the space variables and that the Fourier coefficients decay faster than e-(C(k/kd) ln(vertical bar k vertical bar/kd)) for any C < 1/(2 ln 2). The same result holds for the one-dimensional Burgers equation with exponential dissipation but can be improved: heuristic arguments and very precise simulations, analyzed by the method of asymptotic extrapolation of van der Hoeven, indicate that the leading-order asymptotics is precisely of the above form with C = C-* = 1/ ln 2. The same behavior with a universal constant C-* is conjectured for the Navier-Stokes equations with exponential dissipation in any space dimension. This universality prevents the strong growth of intermittency in the far dissipation range which is obtained for ordinary Navier-Stokes turbulence. Possible applications to improved spectral simulations are briefly discussed.

Dimethyl formamide complexes of rare-earth nitrates

Dimethyl formamide complexes of five rare-earth nitrates, M(DMF)4(NO3)3 where M = La, Pr, Nd, Sm or Y have been prepared and their infra-red spectra and conductivities in nitromethane and DMF studied. It is suggested that the co-ordination number of the metal ion in these complexes is nine.

The subsidence rates of suspensions of lithium stearate in n-heptane with n-alcohols as additives

Suspensions of lithium stearate in n-heptane are highly unstable, undergoing gelation even at concentrations as low as 1 g./1. The rate of subsidence of these weakly gelled suspensions is decreased at first by the addition of n-alcohols, but passes through a minimum in some cases. The minimum subsidence rate occurs while the adsorption of the alcohol is still below its saturation value. One possible explanation of the effect is that the solvent layer between particles at the junction points in the gel becomes simultaneously more polar, tending toward an increased gel strength, and also thicker, tending toward a decreased gel strength.

Differential transcription of multiple copies of a silk worm gene encoding tRNA

Ten different tRNAGly1 genes from the silk worm, Bombyx mori, have been cloned and characterized. These genes were transcribed in vitro in homologous nuclear extracts from the posterior silk gland (PSG) or nuclear extracts derived from the middle silk gland or ovarian tissues. Although the transcription levels were much higher in the PSG nuclear extracts, the transcriptional efficiency of the individual genes followed a similar pattern in all the extracts. Based on the levels of in vitro transcription, the ten tRNAGly1 genes could be divided into three groups, viz., those which were transcribed at very high levels (e.g., clone pR8), high to medium levels (e.g., pBmil, pBmpl, pBmhl, pBmtl) and low to barely detectable levels (e.g., pBmsl, pBmjl and pBmkl). The coding sequences of all these tRNA genes being identical, the differential transcription suggested that the flanking sequences modulate their transcriptional efficiency. The presence of positive and negative regulatory elements in the 5' flanking regions of these genes was confirmed by transcription competition experiments. A positive element was present in the immediate upstream A + T-rich sequences in all the genes, but no consensus sequences correlating to the transcriptional status could be generated. The presence of negative elements on the other hand was indicated only in some of the genes and therefore may have a role in the differential transcription of these tRNAGly genes in vivo.

Polymorphism in Opto-Electronic Materials with a Benzothiazole-fluorene Core: A Consequence of High Conformational Flexibility of pi-Conjugated Backbone and Alkyl Side Chains

Fluorene and its derivatives are well-known organic semiconducting materials in the field of opto-electronic devices because of their charge transport properties. Three new organic semiconducting materials, namely, 2,2'-((9,9-butyl-9H-fluorene-2,7-diyl)bis(4,1 phenylene))bisbenzod]thiazole, C4; 2,2'-((octyl-9H-fluorene-2,7-diyl)bis(4,1 phenylene))bisbenzod]thiazole, C8; and 2,2'-((9,9-dodecayl-9H-fluorene-2,7-diyl)bis(4,1 phenylene))bisbenzod]thiazole, C12 with a benzothiazole-fluorene backbone, were synthesized and characterized for their photophysical properties. A phenomenon of concomitant polymorphism has been investigated in the first two derivatives (C4 and C8) and has been analyzed systematically in terms of the packing characteristics involving pi ... pi interactions. The conformational flexibility of the pi-conjugated 2,2'-(fluorene-2,7-diyl)bis(4,1 phenylene)bisbenzod]thiazole backbone coupled with orientational freedom of the terminal alkyl chains were found to be the key factors responsible for these polymorphic modifications. Attempts to grow suitable crystals for single crystal X-ray diffraction of compound C12 were unsuccessful.

Denaturant mediated unfolding of both native and molten globule states of maltose binding protein are accompanied by large [Delta]Cp's

Maltose binding protein (MBP) is a large, monomeric two domain protein containing 370 amino acids. In the absence of denaturant at neutral pH, the protein is in the native state, while at pH 3.0 it forms a molten globule. The molten globule lacks a tertiary circular dichroism signal but has secondary structure similar to that of the native state. The molten globule binds 8-anilino-1-naphthalene sulfonate (ANS). The unfolding thermodynamics of MBP at both pHs were measured by carrying out a series of isothermal urea melts at temperatures ranging from 274–329 K. At 298 K, values of [Delta]G°, [Delta]Cp, and Cm were 3.1 ± 0.2 kcal mol−1, 5.9 ± 0.8 kcal mol−1 K−1 (15.9 cal (mol-residue)−1 K−1), and 0.8 M, respectively, at pH 3.0 and 14.5 ± 0.4 kcal mol−1, 8.3 ± 0.7 kcal mol−1 K−1 (22.4 kcal (mol-residue)−1 K−1), and 3.3 M, respectively, at pH 7.1. Guanidine hydrochloride denaturation at pH 7.1 gave values of [Delta]G° and [Delta]Cp similar to those obtained with urea. The m values for denaturation are strongly temperature dependent, in contrast to what has been previously observed for small globular proteins. The value of [Delta]Cp per mol-residue for the molten globule is comparable to corresponding values of [Delta]Cp for the unfolding of typical globular proteins and suggests that it is a highly ordered structure, unlike molten globules of many small proteins. The value of [Delta]Cp per mol-residue for the unfolding of the native state is among the highest currently known for any protein.

Multilayer assemblies of polyelectrolyte-gold nanoparticles for the electrocatalytic oxidation and detection of arsenic(III)

Multilayers of poly(diallyldimethylammonium chloride) (PDDA) and citrate capped Au nanoparticles (AuNPs) anchored on sodium 3-mercapto-1-propanesulfonate modified gold electrode by electrostatic layer-by-layer assembly (LbL) technique are shown to be an excellent architecture for the direct electrochemical oxidation of As(III) species. The growth of successive layers in the proposed LbL architecture is followed by atomic force microscopy, UV-vis spectroscopy, quartz crystal microbalance with energy dissipation, and electrochemistry. The first bilayer is found to show rather different physico-chemical characteristics as compared to the subsequent bilayers, and this is attributed to the difference in the adsorption environments. The analytical utility of the architecture with five bilayers is exploited for arsenic sensing via the direct electrocatalytic oxidation of As(III), and the detection limit is found to be well below the WHO guidelines of 10 ppb. When the non-redox active PDDA is replaced by the redoxactive Os(2,2'-bipyridine)(2)Cl-poly(4-vinylpyridine) polyelectrolyte (PVPOs) in the LbL assembly, the performance is found to be inferior, demonstrating that the redox activity of the polyelectrolyte is futile as far as the direct electro-oxidation of As(III) is concerned. (C) 2012 Elsevier Inc. All rights reserved.

Antimony-resistant but not antimony-sensitive Leishmania donovani up-regulates host IL-10 to overexpress multidrug-resistant protein 1

The molecular mechanism of antimony-resistant Leishmania donovani ((SbLD)-L-R)-driven up-regulation of IL-10 and multidrug-resistant protein 1 (MDR1) in infected macrophages (M phi s) has been investigated. This study showed that both promastigote and amastigote forms of (SbLD)-L-R, but not the antimony-sensitive form of LD, express a unique glycan with N-acetylgalactosamine as a terminal sugar. Removal of it either by enzyme treatment or by knocking down the relevant enzyme, galactosyltransferase in (SbLD)-L-R (KD (SbLD)-L-R), compromises the ability to induce the above effects. Infection of M phi s with KD (SbLD)-L-R enhanced the sensitivity toward antimonials compared with infection with (SbLD)-L-R, and infection of BALB/c mice with KD (SbLD)-L-R caused significantly less organ parasite burden compared with infection induced by (SbLD)-L-R. The innate immune receptor, Toll-like receptor 2/6 heterodimer, is exploited by (SbLD)-L-R to activate ERK and nuclear translocation of NF-kappa B involving p50/c-Rel leading to IL-10 induction, whereas MDR1 up-regulation is mediated by PI3K/Akt and the JNK pathway. Interestingly both recombinant IL-10 and (SbLD)-L-R up-regulate MDR1 in M. with different time kinetics, where phosphorylation of PI3K was noted at 12 h and 48 h, respectively, but M phi s derived from IL-10(-/-) mice are unable to show MDR1 up-regulation on infection with (SbLD)-L-R. Thus, it is very likely that an IL-10 surge is a prerequisite for MDR1 up-regulation. The transcription factor important for IL-10-driven MDR1 up-regulation is c-Fos/c-Jun and not NF-kappa B, as evident from studies with pharmacological inhibitors and promoter mapping with deletion constructs.

Analysis of the Genome and Transcriptome of Cryptococcus neoformans var. grubii Reveals Complex RNA Expression and Microevolution Leading to Virulence Attenuation

Cryptococcus neoformans is a pathogenic basidiomycetous yeast responsible for more than 600,000 deaths each year. It occurs as two serotypes (A and D) representing two varieties (i.e. grubii and neoformans, respectively). Here, we sequenced the genome and performed an RNA-Seq-based analysis of the C. neoformans var. grubii transcriptome structure. We determined the chromosomal locations, analyzed the sequence/structural features of the centromeres, and identified origins of replication. The genome was annotated based on automated and manual curation. More than 40,000 introns populating more than 99% of the expressed genes were identified. Although most of these introns are located in the coding DNA sequences (CDS), over 2,000 introns in the untranslated regions (UTRs) were also identified. Poly(A)-containing reads were employed to locate the polyadenylation sites of more than 80% of the genes. Examination of the sequences around these sites revealed a new poly(A)-site-associated motif (AUGHAH). In addition, 1,197 miscRNAs were identified. These miscRNAs can be spliced and/or polyadenylated, but do not appear to have obvious coding capacities. Finally, this genome sequence enabled a comparative analysis of strain H99 variants obtained after laboratory passage. The spectrum of mutations identified provides insights into the genetics underlying the micro-evolution of a laboratory strain, and identifies mutations involved in stress responses, mating efficiency, and virulence.

Purification of a recombinant histidine-tagged lactate dehydrogenase from the malaria parasite, Plasmodium vivax, and characterization of its properties

Lactate dehydrogenase (LDH) of the malaria parasite, Plasmodium vivax (Pv), serves as a drug target and immunodiagnostic marker. The LDH cDNA generated from total RNA of a clinical isolate of the parasite was cloned into pRSETA plasmid. Recombinant his-tagged PvLDH was over-expressed in E. coli Rosetta2DE3pLysS and purified using Ni2+-NTA resin giving a yield of 25-30 mg/litre bacterial culture. The recombinant protein was enzymatically active and its catalytic efficiency for pyruvate was 5.4 x 10(8) min(-1) M-1, 14.5 fold higher than a low yield preparation reported earlier to obtain PvLDH crystal structure. The enzyme activity was inhibited by gossypol and sodium oxamate. The recombinant PvLDH was reactive in lateral flow immunochromatographic assays detecting pan- and vivax-specific LDH. The soluble recombinant PvLDH purified using heterologous expression system can facilitate the generation of vivax LDH-specific monoclonals and the screening of chemical compound libraries for PvLDH inhibitors.

Cocrystals of Hydrochlorothiazide: Solubility and Diffusion/Permeability Enhancements through Drug-Coformer Interactions

Hydrochlorothiazide (HCT) is a diuretic and a BCS class IV drug with low solubility and low permeability, exhibiting poor oral absorption. The present study attempts to improve the physicochemical properties of the drug using a crystal engineering approach with cocrystals. Such multicomponent crystals of HCT with nicotinic acid (NIC), nicotinamide (NCT), 4-aminobenzoic acid (PABA), succinamide (SAM), and resorcinol (RES) were prepared using liquid-assisted grinding, and their solubilities in pH 7.4 buffer were evaluated. Diffusion and membrane permeability were studied using a Franz diffusion cell. Except for the SAM and NIC cocrystals, all other binary systems exhibited improved solubility. All of the cocrystals showed improved diffusion/membrane permeability compared to that of HCT with the exception of the SAM cocrystal. When the solubility was high, as in the case of PABA, NCT, and RES cocrystals, the flux/permeability dropped slightly. This is in agreement with the expected interplay between solubility and permeability. Improved solubility/permeability is attributed to new drug-coformer interactions. Cocrystals of SAM, however, showed poor solubility and flux This cocrystal contains a primary sulfonamide dimer synthon similar to that of HCT polymorphs, which may be a reason for its unusual behavior. Hirshfeld surface analysis was carried out in all cases to determine whether a correlation exists between cocrystal permeability and drug-coformer interactions.

An estimate of the number of tropical tree species

The high species richness of tropical forests has long been recognized, yet there remains substantial uncertainty regarding the actual number of tropical tree species. Using a pantropical tree inventory database from closed canopy forests, consisting of 657,630 trees belonging to 11,371 species, we use a fitted value of Fisher's alpha and an approximate pantropical stem total to estimate the minimum number of tropical forest tree species to fall between similar to 40,000 and similar to 53,000, i.e., at the high end of previous estimates. Contrary to common assumption, the Indo-Pacific region was found to be as species-rich as the Neotropics, with both regions having a minimum of similar to 19,000-25,000 tree species. Continental Africa is relatively depauperate with a minimum of similar to 4,500-6,000 tree species. Very few species are shared among the African, American, and the Indo-Pacific regions. We provide a methodological framework for estimating species richness in trees that may help refine species richness estimates of tree-dependent taxa.

Design for sustainability: case of designing an urban household organic waste management system

Beyond product design, if the notion of product `lifecycle design' enforces the consideration of requirements from all the lifecycle phases of products, design for sustainability enforces the consideration of lifecycle design in the context of the lifecycles of other products, processes, institutions and their design. Consequently, sustainability requirements that need to be met by design are very diverse. In this article, we portray the nature of design process to address sustainability requirements. This is done taking an example of designing a urban household organic waste management system that requires less water and reclaims the nutrients.