RG Data Research Articles

Evaluating the Drug Delivery Capacity of 3D Coordination Polymer for Anticancer Drugs.

We synthesized {[Cd2(dTMP)2(4,4'-azpy)2(H2O)2] ⋅ 3(O)}n a novel three-dimensional metal nucleotide coordination polymer (CP-1). An assessment of the CP-1 binding affinity for anticancer drugs was conducted using molecular dynamic simulations. The virtual screening results depict that CP-1 has a lot of potential for encapsulating the anthracycline anticancer drug doxorubicin (DOX). It hasn't yet been investigated how to accomplish high loading capacity, efficiency, and controlled release of DOX in dTMP-based 3D metal coordination polymers. Utilizing DOX as a drug model and our system as a drug-loading vehicle, we used UV-visible and circular dichroism titrations to examine the effects of its encapsulation and release. The mechanism of drug loading and release was investigated through pH-responsive behavior by adjusting the pH value to 8, 7, 6, and 5. The results indicate the CP-1 has a robust affinity for DOX at pH 7, which facilitates its loading on 3D porous coordination polymer. However, the maximum cumulative drug release of 87.11 % was observed at pH 5. The higher correlation coefficient (R2) was obtained at pH 5 with the Higuchi equation. It indicated that the drug released was primarily controlled with the diffusion mechanism. The CP-1 polymer's ability to encapsulate DOX while also permitting a possible controlled-release mechanism is confirmed by the combined insights from the experimental findings, energy graphs, RMSD analysis, and radius of gyration (Rg) data from MD simulations.

Design, thermodynamic, and neurodegenerative prediction of 2-pentadecanone-6,10,14-trimethyl and eicosanoic acid from gelidiella acerosa as the intermediates for the synthesis of heterocyclics of piperidone, pyrrole derivatives

Cognitive impairment occurring through the disintegration of acetylcholine causes neurodegenerative disorders. Seed weeds possess neuroprotective action due to the presence of several bioactive compounds which have nutritional and anti-oxidant properties. The research involves screening, docking molecules, simulating molecular dynamics (MD), and investigating the free energy of Gelidiella acerosa phytoconstituents from red algae habituating in south India. The genes of interest are acetylcholinesterase (ACHE) and butylcholinesterase (BCHE) which are responsible for the degradation of acetylcholine, resulting in cognitive decline. Proteins of the ACHE and BCHE genes with PDB IDs 1QTI and 1P0P have been chosen for the docking study, respectively. The binding energies of protein 1QTI, of the docking were compared with the standard of rivastigmine, with the test molecules of 2-pentadecanone, 6, 10, 14-trimethyl, eicosanoic acid, and linalyl acetate. MD Simulation for 1QTI has been performed for rivastigmine and 2-pentadecanone, 6, 10, and 14-trimethyl, and the root mean square deviation graphs demonstrate that the residual variations for the test compounds were comparable to those of rivastigmine. Furthermore, the residual compactness of the 2-pentadecanone, 6, 10, and 14-trimethyl docked complex with rivastigmine is demonstrated by the radius of gyration (Rg) data. The reported Π–Π interactions with TYR A 334 and active AchE inhibition observed for donepezil are present in the test of our compound of 2-pentadecanone, 6, 10, and 14-trimethyl as well. Thus, through the binding with AchE, 2-pentadecanone, 6, 10, and 14-trimethyl with ACHE target, it is envisaged that this compound could serve as a potential inhibitor of ACHE. Based on these findings, the present study shows that 2-pentadecanone, 6, 10, and 14-trimethyl-derived piperidone and pyrrole derivatives could be evaluated further for their potential use in Alzheimer and other neurodegenerative diseases.. KEYWORDS :2-Pentadecanone, 6, 10, 14-trimethyl and Eicosanoic acid derived Piperidone and Pyrrole, Gelidelia acerosa, Design, Thermodynamic studies, Neurodegenerative targets.

In silico mutagenesis on active site residues of Acinetobacter haemolyticus lipase KV1 for improved binding to polyethylene terephthalate (PET)

Polyethylene terephthalate (PET) pollution is an emerging environmental hazard because of its recalcitrance to degradation. This study proposes an in silico mutagenesis of LipKV1 from Acinetobacter haemolyticus for improved lipase-PET interaction, using the PET-degrading Thermobifida cutinase (TfCut2) as the structural benchmark. Results revealed that lid deletion on LipKV1 (LipKV1_LE) facilitated the entry of PET into the active site. The mutation of several predicted amino acids into alanine expanded the LipKV1 active site for better PET binding. Docking results indicated that the LipKV1_LE mutants, Var9 (-6.2 kcal/mol), Var18 (-6.0 kcal/mol), and Var181 (-6.0 kcal/mol), produced higher binding affinities with PET than the wild-type LipKV1 (-2.5 kcal/mol) and TfCut2 (-4.6 kcal/mol), attesting that the selected mutation sites played prominent role in altering the abilities of LipKV1_LE mutants to bind to PET. Our molecular dynamics (MD) simulation results corroborated the variant-PET complexes’ improved binding, mirrored by their improved conformations (RMSD ∼0.35 nm). The RMSF results also showed acceptable fluctuation limits of the LipKV1_PET mutant complexes (RMSF < 0.5 nm). Rg data of the complexes showed that they are conformationally stable, with a maximum of three H-bonds in their interaction with PET. SASA results showed that the mutations did not profoundly alter the hydrophobicity of the amino acid residues. MM-PBSA calculations on the LipKV1_PET mutant complexes estimated binding free energies between −28.29 kcal/mol to −23.25 kcal/mol, comparable to the molecular docking data. Thus, the MD data conveyed the practicality of the above-said site mutations in rationally designing the LipKV1 active site for better PET degradation.

Distribution of the monthly global solar irradiation in the State of Tabasco, Mexico

Objective: To estimate the monthly average global solar irradiance (Rg), using observed cloudiness data (% of cloudy days), as well as its spatial distribution for the state of Tabasco, Mexico.Design/Methodology/Approximation: The proposed model by Tejeda-Martínez et al. (1999) was adjusted to estimate the Rg of 35 meteorological stations in the state of Tabasco. The adjustment was performed with daily observed Rg data fromeight automated weather stations and cloudiness data from eight ordinary weather stations. Results: The proposed model reports a good fit, given that its prediction was optimal according to Willmotts comparison parameter (c = 0.89), and excellent based on the Nash-Sutcliffe efficiency index (E = 0.99) and had a high corrected determination coefficient of Rc2 = 0.87.Study limitations/implications: It is necessary that in the state of Tabasco the number of automated stations increase, as well as technical maintenance to the existing stations.Findings/conclusions: The estimated Rg is statistically reliable. The highest Rg values occurred during the dry season, with a maximum of 22.99 MJ m -2 d -1 , distributed mainly in the northern part of the state. The lowest Rg values occurredduring the northeast season (12.52 MJ m -2 d -1 ), distributed in more than 80 % of the total state area.

An improved semantic similarity algorithm based on HowNet and CiLin

This paper explores an improved method for the semantic similarity calculation of words combined with HowNet and CiLin. Firstly, we designing the algorithm based on HowNet’s sememe similarity improvement calculation, comprehensively considering the influence of each part of sememe on the overall meaning, and improving the calculation of word similarity based on HowNet by changing the specific calculation method of each part of sememe. At the same time, we adopt different strategies for the different results obtained in the similarity calculation of CiLin. The experimental RG data set proves that the modified Pearson coefficient of the method reaches 0.87.

Conformation and dynamics of flexible polyelectrolytes in semidilute salt-free solutions.

We present steady shear rheology data for sodium polystyrene sulfonate (NaPSS) in semidilute unentangled salt-free aqueous solution as a function of polymer concentration (c) and degree of polymerisation (N). The measured terminal modulus (G) agrees with the scaling prediction of G ≃ kBTc/N. The specific viscosity varies with the degree of polymerisation as ηsp ∝ N1.24±0.08. The observed dependence differs with the linear relation expected from the Rouse model for ideal chains as predicted by de Gennes' scaling model and subsequent theories. Together with the diffusion data of Oostwal et al., our results suggest that chains may follow non-Gaussian statistics beyond the correlation length (ξ). Small angle neutron scattering data on salt-free semidilute solutions at low polymer concentrations partially support this hypothesis but do not confirm it. The electrostatic Kuhn length of NaPSS salt-free solutions is found to be proportional and slightly larger than the correlation length (LK,e ≃ 1.3ξ). This result agrees well with the scaling model of Dobrynin et al. Radii of gyration (Rg) data as a function of polymer concentration reveal that a concentrated regime (Rg ∝ c0) does not occur for NaPSS in the concentration range considered (c ≲ 4M). We conclude by comparing the predictions of the scaling model of Dobrynin et al. and Muthukumar's double screening theory with viscosity data for different polyelectrolyte-solvent systems. Dobrynin's model provides a better description of experimental observations. Our findings confirm several aspects of current models for polyelectrolyte solutions but some deviations from theory remain.

Simplified Robust Triple Detection Methods for High Temperature GPC Analysis of Polyolefins

Very powerful triple detector high‐temperature gel permeation chromatography (HT‐GPC) systems equipped with concentration, viscosity, and multiple angle light scattering detectors can be found in many polyolefin characterization laboratories. However, the complexity and sometimes lack of robustness of some detection methods often result in failure to achieve the required precision and long‐term reliability to properly support the industrial needs. Two methods for data processing in triple detector HT‐GPC of polyolefins are here described aiming at overcoming those difficulties, specifically those related to the application of multiple angle light scattering. In the first place, we propose here a data processing method using light scattering data collected at only one angle, with application of a dissymmetry correction based on an estimate of the molecular size from the hydrodynamic volume given by the universal calibration. This method (SALSDC: single‐angle light scattering with dissymmetry correction) is simple and robust for molar mass distribution and averages. Long chain branching detection and quantification is another field plagued with lack of precision and inconsistency problems, due to the difficulty in collecting reliable radius of gyration (Rg) data using MALS, for calculation of the g‐index. A novel approach to estimate the g‐index, based on point‐by‐point calculation of the gpcBR index is here described and evaluated.

Functional perturbative RG and CFT data in the epsilon -expansion

We show how the use of standard perturbative RG in dimensional regularization allows for a renormalization group-based computation of both the spectrum and a family of coefficients of the operator product expansion (OPE) for a given universality class. The task is greatly simplified by a straightforward generalization of perturbation theory to a functional perturbative RG approach. We illustrate our procedure in the epsilon -expansion by obtaining the next-to-leading corrections for the spectrum and the leading corrections for the OPE coefficients of Ising and Lee-Yang universality classes and then give several results for the whole family of renormalizable multi-critical models phi ^{2n}. Whenever comparison is possible our RG results explicitly match the ones recently derived in CFT frameworks.

Experimentally Calibrated Random Walk of Branched Polymers: A Pragmatic Approach

In order to control the branching behavior of polymers, the comparison of experimental and simulated data is important. The utilization of a nonlattice, self‐avoiding necklace‐bead random walk simulator is reported, which allows for the calculation of radii of gyration r g of polymer molecules with branched structures. The focus is on sensitivity toward short‐chain branches, long‐chain branches (LCBs), and the copolymer composition. Using only two parameters—the size of monomer beads and the minimum angle between three subsequent beads—a fast and reliable parameter fit procedure based on experimental data is described. The procedure is exemplarily shown for copolymers of vinylidene fluoride and hexafluoropropene (HFP) with HFP contents in the copolymer of at most 0.3 and is easily transferable to other polymers that may be analyzed by size‐exclusion chromatography/multiangle laser light scattering close to θ conditions. Applying the Zimm–Stockmayer equation to simulated r g data allows for comparing the “effective” number of LCBs with the number of LCBs given by kinetic simulations. A tool for better estimation of rate coefficients associated with the formation of short‐ and long‐chain branches is provided.image

Structural effect of glyme-Li(+) salt solvate ionic liquids on the conformation of poly(ethylene oxide).

The conformation of 36 kDa polyethylene oxide (PEO) dissolved in three glyme-Li(+) solvate ionic liquids (SILs) has been investigated by small angle neutron scattering (SANS) and rheology as a function of concentration and compared to a previously studied SIL. The solvent quality of a SIL for PEO can be tuned by changing the glyme length and anion type. Thermogravimetric analysis (TGA) reveals that PEO is dissolved in the SILs through Li(+)-PEO coordinate bonds. All SILs (lithium triglyme bis(trifluoromethanesulfonyl)imide ([Li(G3)]TFSI), lithium tetraglyme bis(pentafluoroethanesulfonyl)imide ([Li(G4)]BETI), lithium tetraglyme perchlorate ([Li(G4)]ClO4) and the recently published [Li(G4)]TFSI) are found to be moderately good solvents for PEO but solvent quality decreases in the order [Li(G4)]TFSI ∼ [Li(G4)]BETI > [Li(G4)]ClO4 > [Li(G3)]TFSI due to decreased availability of Li(+) for PEO coordination. For the same glyme length, the solvent qualities of SILs with TFSI(-) and BETI(-) anions ([Li(G4)]TFSI and [Li(G4)]BETI) are very similar because they weakly coordinate with Li(+), which facilitates Li(+)-PEO interactions. [Li(G4)]ClO4 presents a poorer solvent environment for PEO than [Li(G4)]BETI because ClO4(-) binds more strongly to Li(+) and thereby hinders interactions with PEO. [Li(G3)]TFSI is the poorest PEO solvent of these SILs because G3 binds more strongly to Li(+) than G4. Rheological and radius of gyration (Rg) data as a function of PEO concentration show that the PEO overlap concentrations, c* and c**, are similar in the three SILs.

Využití denních teplotních extrémů a úhrnu srážek k odhadu globálního slunečního záření

Two methods for estimating daily global solar radiation (RG) based on the daily temperature extremes and precipitation sum are compared in the study. All parameters necessary for application of both methods were derived either from literature or from climatic characteristics easily available at the given meteorological stations excluding need for measured RG data. The performance of both methods was assessed with a help of meteorological database including 4 stations in the Czech Republic (data were provided by the Czech Hydrometeorological Institute) and 6 in Austria (data provided by the Austrian Weather Service) containing in total 41 640 observational day. For each day in the database observed daily sum of RG, daily maximum and minimum temperatures and precipitation sum were available. Coefficient of determination, slope of regression line forced through origin, mean bias error (MBE) and root mean square error (RMSE) were used as performance indicators. The first method proposed by Winslow et al. (2001) – Eq. (1) is capable to explain 86% of daily RG variability, with systematic error represented by MBE equaling to 0.19 MJ.m–2.day-1 and random error indicated by RMSE reaching up to 3.09. The second method published by Thornton and Running (1999)-Eq. (2) was found to be in almost all parameters inferior to the Eq. (1) and thus the Eq. (1) is recommended to be used in the Central European region (up to 600 m above the sea level). This method might be recommended for stations where neither measured RG or sunshine duration hours exist. However, one should take into consideration that relative MBE and RMSE are in some months higher than 10% and 30% respectively, which may compromise results of subsequent calculations made with use of estimated solar radiation data and alter the order of the method suitability.

Daytime Net Radiation on Cowpea and Castor Bean in the County of Areia-PB and Garanhuns-PE

O saldo de radiacao (Rn) e a energia utilizada em diversos processos que ocorrem no sistema solo-planta-atmosfera, a exemplo da evapotranspiracao; no entanto, sua medicao direta nao esta disponivel para a maioria das estacoes meteorologicas do Brasil. Dessa forma, o presente trabalho objetivou determinar a relacao entre o Rn e a radiacao solar global incidente (Rg) sobre dosseis de caupi e mamona. Os dados de Rn e Rg foram coletados de experimentos realizados durante os anos de 2002 e 2003 (caupi), de 2004 e 2005 (mamona) em Areia-PB (6 o 58 ’ S, 35 o 41 ’ W e 620 m), e de 2009 (mamona) em Garanhuns-PE (8 o 53’ S, 36 o 29’ W e 842 m). Os dados foram integrados durante o periodo diurno, das 6 as 18h, e depois foi obtida a relacao Rn/Rg para cada dia. Obtiveram-se equacoes com elevado R 2 (acima de 0,93), indices d e c (acima de 0,90), e baixo RQME (abaixo de 0,83), indicando boa precisao da estimativa do Rn em funcao do Rg nas culturas do caupi e da mamona. A equacao geral para mamona foi Rn = 0,5965 Rg (R 2 = 0,943) e para caupi foi Rn = 0,7822 Rg (R 2 = 0,976). O Rn, em dosseis de caupi e mamona, pode ser estimado satisfatoriamente a partir da Rg. 800x600 Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:Table Normal; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:Calibri,sans-serif;} A B S T R A C T Net radiation (Rn) is the quantity of radiant energy used in many process occurring in the soil-plant-atmosphere continuum, such as evapotranspiration, however, its direct measurement is not available for most weather stations in Brazil. Thus, the objective of this work was to determine the relationship between Rn and incident solar radiation (Rg) in cowpea and castor bean canopies. The Rn and Rg data were collected from experiments conducted during in the years 2002 and 2003 (cowpea), 2004 and 2005 (castor bean) in Areia, PB (6 o 58’ S, 35 o 41’ W e 620 m), and 2009 (castor bean) in Garanhuns-PE (8 o 53’ S, 36 o 29’ W e 842 m). Were performed daily sums of Rn and Rg, from 6 to 18h, and then it was calculated the Rn/Rg ratio for each day. Models with high R 2 (above 0.93), d and c indices (above 0.90) and low RMSE (below 0.83) were obtained in test between measured and estimated values, indicating precision to estimate Rn in cowpea and castor bean canopies as a function of Rg. The general linear function for castor bean and cowpea were Rn = 0.5965 Rg (R 2 = 0.943) and Rn = 0.7822 Rg (R 2 = 0.976), respectively. Net radiation can be satisfactorily estimated from incoming solar radiation for both crops. Key words: Evapotranspiration, Solar Radiation, Vigna unguiculata, Ricinus communis

Prevalence, trends and district differentials in teenage pregnancies

Introduction Teenage pregnancies with their negative obstetric and foetal outcomes are a maternal and child health concern of the country. Objectives To study the prevalence, trends and district differentials in teenage pregnancies in Sri Lanka Methods Three main sources of available national level data were used in this study. They were : vital event registration data from the Registrar General's (RG) Department, data collected routinely by the Family Health Bureau (FHB), Ministry of Health through the Reproductive Health Information Management System (RHMIS) and data from the Demographic and Health Survey (DHS) 2006/07. Other than utilizing reported information of all three sources, primary data of DHS 2006/07 was accessed with permission and further analysis were performed. Results Routinely available data from the Registrar General's (RG) Department are based on the registrations of live births throughout the island, hence could be considered as a proxy for information on pregnancies. A consistent declining trend in pregnancies among women less than 19 years of age was observed from the year 2000 (8.1%) to 2006 (5.4%). Marked inter district variations were noted. The highest percentage of teenage pregnancy was among the Sri Lankan Tamils. The rural sector showed the highest percentages while the estate sector showed the lowest. High percentage of illegitimate births in the estate sector was noteworthy. Data from the routine RHMIS of the Family Health Bureau also showed a declining trend of teenage pregnant females registered by Public Health Midwives as a percentage of all registered pregnant mothers, during the period 2007 (7.7%) to 2010 (6.5%). The marked inter district variation was observed with the variations consistent to what was observed in the RG's data. Further analysis of DHS data showed that the percentage of teenage pregnancies among ever married women aged between 15 – 49 years to be 6.3% (95% CI 5.4-7.2). Teenage pregnancy rates declined significantly with increasing levels of education (p Conclusions and recommendations Analysis of national level information related to teenage pregnancies from three different sources of available data showed that there is a declining trend in the prevalence of teenage pregnancies. All three sources identified that there is a marked inter-district variation in the teenage pregnancy rates and the districts identified to have high rates of teenage pregnancy by the three different sources were mostly consistent. This indicates the need for district specific interventions. Journal of the College of Community Physicians of Sri Lanka Volume 16, No. 02, December 2011 21-30 DOI: http://dx.doi.org/10.4038/jccpsl.v16i2.4577

Estimation of solar radiation and its application to crop simulation models in Greece

Lack of data on site-specific daily solar radiation (Rg) is a significant impediment for most crop modeling applications. For this reason, 5 methods for estimating Rg were tested: the Angstrom-Prescott equation (AP), the Supit - van Kappel formula (SK) and 3 temperature-based methods: Campbell-Donatelli model, Hargreaves equation, and piecewise multiple linear regres- sions with a breakpoint (PLR). To overcome the lack of long and continuous time series of Rg mea- surements at multiple sites, satellite-derived Rg from the HelioClim-1 database were tested against observations from 2 stations, and then interpolated for 12 additional stations. When sunshine duration data were available, the AP equation was best, because it (1) produced intercepts and slopes closest to zero and unity, respectively and (2) had the lowest relative RMSE (9 to 18.6%). When cloud cover observations and data on maximum and minimum temperatures were available, the SK equation was equally effective as AP in most assessment metrics. When the only data for a site were daily maxi- mum and minimum temperatures, the PLR approach with a breakpoint, which reflects the value at which the response of daily Rg changes as a function of the extraterrestrial solar radiation RA and the diurnal temperature range, performed best. The mean relative RMSE of the PLR approach was <3.7% higher than that of AP. The SK equation provided the most suitable simulation of measured Rg for the CERES-Wheat crop model, while among the temperature-based methods PLR produced the smallest yield errors. Future validation efforts should explore the validity of the PLR model in other regions and under regimes with greater availability of Rg data

Effect of Estimated Daily Global Solar Radiation Data on the Results of Crop Growth Models.

The results of previous studies have suggested that estimated daily globalradiation (RG) values contain an error that could compromise the precision of subsequentcrop model applications. The following study presents a detailed site and spatial analysis ofthe RG error propagation in CERES and WOFOST crop growth models in Central Europeanclimate conditions. The research was conducted i) at the eight individual sites in Austria andthe Czech Republic where measured daily RG values were available as a reference, withseven methods for RG estimation being tested, and ii) for the agricultural areas of the CzechRepublic using daily data from 52 weather stations, with five RG estimation methods. In thelatter case the RG values estimated from the hours of sunshine using the ångström-Prescottformula were used as the standard method because of the lack of measured RG data. At thesite level we found that even the use of methods based on hours of sunshine, which showedthe lowest bias in RG estimates, led to a significant distortion of the key crop model outputs.When the ångström-Prescott method was used to estimate RG, for example, deviationsgreater than ±10 per cent in winter wheat and spring barley yields were noted in 5 to 6 percent of cases. The precision of the yield estimates and other crop model outputs was lowerwhen RG estimates based on the diurnal temperature range and cloud cover were used (mean bias error 2.0 to 4.1 per cent). The methods for estimating RG from the diurnal temperature range produced a wheat yield bias of more than 25 per cent in 12 to 16 per cent of the seasons. Such uncertainty in the crop model outputs makes the reliability of any seasonal yield forecasts or climate change impact assessments questionable if they are based on this type of data. The spatial assessment of the RG data uncertainty propagation over the winter wheat yields also revealed significant differences within the study area. We found that RG estimates based on diurnal temperature range or its combination with daily total precipitation produced a bias of to 30 per cent in the mean winter wheat grain yields in some regions compared with simulations in which RG values had been estimated using the ångström-Prescott formula. In contrast to the results at the individual sites, the methods based on the diurnal temperature range in combination with daily precipitation totals showed significantly poorer performance than the methods based on the diurnal temperature range only. This was due to the marked increase in the bias in RG estimates with altitude, longitude or latitude of given region. These findings in our view should act as an incentive for further research to develop more precise and generally applicable methods for estimating daily RG based more on the underlying physical principles and/or the remote sensing approach.

Phonological dyslexia without phonological impairment?

RG, a patient with probable Alzheimer's disease, showed a severe impairment in nonword reading. RG's word reading was intact, for example, as demonstrated by her scores in standardised reading tasks, which were comparable to those of normal controls. No phonological impairment was apparent in speech production and comprehension. Moreover, RG performed well in a series of phonological tasks (e.g., production of a rhyming word, phoneme identification) on which patients with a reading deficit selective for nonwords have been reported to encounter problems. RG's data severely constrain reading models proposing that nonword reading deficits are caused by phonological deficits. However, RG's data are compatible with dual-route reading models, which do not propose a link between nonword reading deficits and phonological impairment.

Age of granitic activity associated with copper?molybdenum mineralization at Malanjkhand, Central India

The Malanjkhand copper–molybdenum deposit in the Bhandara Craton, Central India, is hosted by a granite complex which consists of regionally dominant “grey granitoid” and “pink granitoid” confined to the mineralized zone. New SHRIMP RG data on zircons from both granite types are inferred to have crystallized during the same magmatic pulse at ca 2.48 Ga. The discrepancy between zircon age and earlier obtained Rb–Sr whole-rock age is attributed to modification of the Rb–Sr system by hydrothermal overprint. Similarity in petrographic features and chemical affinity in combination with identical age strongly indicate that the pink granite is the hydrothermally altered variety (microclinization and silicification) of the grey granite. The spatially associated, main Cu–Mo mineralization event at Malankhand appears to be broadly contemporaneous with and genetically related to the emplacement of the host granitoids at about 2.48 Ga.

Oligomerization of the amide sensor protein AmiC by x-ray and neutron scattering and molecular modeling.

AmiC is the negative regulator of the amidase operon which is involved in amide metabolism in the cytosol of Pseudomonas aeruginosa. Crystal structures show that AmiC contains two large domains that are very similar to the periplasmic leucine-isoleucine-valine binding protein (LivJ) of Escherichia coli. Synchrotron X-ray and neutron (in 100% 2H2O buffer) scattering data were obtained for AmiC in the presence of its substrate acetamide and its anti-inducer butyramide which binds more weakly to AmiC than acetamide. Guinier analyses to obtain radius of gyration RG and molecular weight Mr values showed that AmiC formed trimers whose formation was favored in the presence of acetamide and which exhibited concentration-dependent properties at concentrations between 0.4 and 2 mg/mL. Above 2 mg/mL, where trimers predominated, the RG data were identical within 0.05 nm for AmiC-acetamide and AmiC-butyramide with mean X-ray and neutron RG values of 3.35 and 3. 28 nm, respectively. Scattering curve fits constrained by the crystal structure of AmiC-acetamide were evaluated in order to describe a model for trimeric AmiC. A translational search of parallel alignments of three monomers to form a symmetric AmiC homotrimer gave a good X-ray curve fit. Combinations of calculated curves for monomeric, dimeric, trimeric, and tetrameric AmiC as seen in the crystal structure of AmiC gave reasonable but weaker X-ray curve fits which did not favor the existence of tetrameric AmiC. It is concluded that AmiC exhibits novel ligand-dependent oligomerization properties in solution when these are compared to other members of the periplasmic binding protein superfamily, where AmiC exists in monomeric and trimeric forms, the proportions of which depend on the presence of acetamide or butyramide.

Use of cues by grazing animals to locate food patches: an example with sheep

The ability of sheep to form spatial associations between two cues and two food rewards and to distinguish between the two cues prior to grazing them was examined. At 12 locations within a long, thin field, individual sheep chose between a pair of patches (plastic bowls) containing either preferred (cereal pellets) or non-preferred (lucerne, Medicago sativa pellets) food. Each patch had either a turf of perennial ryegrass ( Lolium perenne) or white clover ( Trifolium repens) associated with it as a cue. The cues were placed in wire mesh cages immediately in front of each patch. The cage meant the cue could be seen and smelled, but not eaten. Each sheep received a series of trials in one of three cue-patch associations: (i) ‘WC’, preferred patch always behind white clover and non-preferred patch always behind ryegrass; (ii) ‘RG’, preferred patch always behind ryegrass and non-preferred patch always behind white clover; (iii) ‘R’, preferred and non-preferred patches associated with cues at random. Five sheep were tested with each association. The spatial location of the food patches and cues was randomised within trials and rerandomised between successive trials to preclude animals from using spatial memory to locate patches. In the first trial, the proportion of times that the preferred food patch was chosen first at each pair of patches was similar in the WC (0.42), RG (0.46) and R (0.48) associations. In the sixth trial, the proportion of times that the preferred food patch was chosen first at each pair of patches was greater in the WC (0.81) and RG (0.82) associations than in the R association (0.46). The WC and RG data indicate that sheep formed associations between cues and rewards and distinguished between the two cues by sight or smell. The ability to form flexible associations between cues and food would be an important mechanism, acting independently of memory of spatial locations, that would help sheep select diets that are better than the average in spatially and temporally complex food environments. The ability to discriminate between white clover and ryegrass prior to grazing them indicates that the mixed diets (partial preference) exhibited by sheep given a choice between these two species do not simply arise because of a need for the sheep to sample the two species to know what each species is.

Molecular modeling of the domain structure of C9 of human complement by neutron and x-ray solution scattering

C9 is the most abundant component of the membrane attack complex of the complement system of immune defense. This is a typical mosaic protein with thrombospondin (TSR) and low density lipoprotein receptor (LDLr) domains at its N-terminus and an epidermal growth factor-like (EGF) domain at its C-terminus. Between these lies a perforin-like sequence. In order to define the arrangement in solution of these four moieties in C9, high-flux neutron and synchrotron X-ray solution scattering studies were carried out. The neutron radius of gyration RG at infinite contrast is 3.33 nm, and its cross-sectional RG (RXS) is 1.66 nm. Similar values were obtained by synchrotron X-ray scattering after allowance for radiation effects. Stuhrmann analyses showed that the neutron radial inhomogeneity of scattering density alpha is 35 X 10(-5) from the RG data and 16 X 10(-5) from the RXS data. These values are typical for soluble glycoproteins and show no evidence for the existence of any large hydrophobic surface patches on free C9 that might form contacts with lipids. Indirect transformation of the neutron and X-ray scattering curves into real space showed that C9 had a maximum dimension estimated at 12 +/- 2 nm, and this suggests that the lengths of 7-8 nm deduced from previous electron microscopy studies in vacuo are underestimated. Molecular modeling of the C9 scattering curves utilized small spheres in the Debye equation, in which the analyses were constrained by the known volumes of the four moieties of C9 and the known sizes of the TSR and EGF-like domains. The most likely models for C9 suggest that these four regions of C9 are arranged in a V-shaped structure, with an angle of 10 degrees between the two arms, each of length 11.1 nm. This structure has a more hydrophobic character between the two arms. The scattering model is fully consistent with hydrodynamic sedimentation data on C9. Similar V-shaped hydrodynamic models could be developed for C6, C7, C8, and C9 of complement. Such a compact structure is atypical of other multidomain complement proteins so far studied by solution scattering and is fully compatible with mechanisms in which C9 is postulated, on activation, to undergo a drastic unfolding of its domain structure and to expose a more hydrophobic surface which can be embedded into lipid bilayers.