Microrheological Characterisation of Anisotropic Materials

We describe the measurement of anisotropic viscoelastic moduli in complex soft materials, such as biopolymer gels, via video particle tracking microrheology of colloid tracer particles. The use of a correlation tensor to find the axes of maximum anisotropy, and hence the mechanical director, is described. The moduli of an aligned DNA gel are reported, as a test of the technique; this may have implications for high DNA concentrations in vivo. We also discuss the errors in microrheological measurement, and describe the use of frequency space filtering to improve displacement resolution, and hence probe these typically high modulus materials.Comment: 5 pages, 5 figures. Replaced after refereeing/ improvement. Main results are the same. The final, published version of the paper is here http://link.aps.org/abstract/PRE/v73/e03190

Experimental investigations on alkali activated foam concrete with impure kaolin

Abstract. The main goal of this thesis was to produce foam concrete by using impure kaolinite coming from the mining industry of Finland. The purpose of making foam concrete was to use as light weight concrete in engineering applications such as thermal/ acoustical insulations and building blocks. The experimental part consists of two different sets of experiments. The first set of experiments involve fresh properties to determine fresh density, viscosity, yield stress and aeration rate and to find the behavior of sample in the fresh state before curing. The second set of experiments was the harden properties including the compressive strength and water absorption. The purpose for testing was to find the effect of H2O2, molarity of NaOH and the effect of surfactants. The purpose of our study was to check the application of impure kaolinite in the production of light weight foam concrete. Furthermore, XRD and FTIR analysis were carried out to determine the crystalline structure and the chemical properties of the Alkali activated kaolinite. Polarized microscope was used to get insight about the pore structure and the effect of different parameters on the pores structure and size. The main findings from the study is the possibility to use kaolinite without any processing and production of low temperature (400 ˚C) ceramic like concrete foam. The dosage of H2O2 was varied from 0.5 to 2%, it effected the hardened properties such as compressive strength as it goes from 20 MPa to 15 MPa. Furthermore, it effected the fresh properties of the material, especially the aeration rate. The aeration rate was increasing for all samples when the percentage of H2O2 was increased. The molarity of NaOH was an important factor that affected the water absorption. Microscopic studies showed that the pore structure varied between samples made without surfactants and those with surfactants, that explains the hardened properties of the aerated foam with impure kaolinite

Structural Evidence for a Copper-Bound Carbonate Intermediate in the Peroxidase and Dismutase Activities of Superoxide Dismutase

Copper-zinc superoxide dismutase (SOD) is of fundamental importance to our understanding of oxidative damage. Its primary function is catalysing the dismutation of superoxide to O2 and H2O2. SOD also reacts with H2O2, leading to the formation of a strong copper-bound oxidant species that can either inactivate the enzyme or oxidise other substrates. In the presence of bicarbonate (or CO2) and H2O2, this peroxidase activity is enhanced and produces the carbonate radical. This freely diffusible reactive oxygen species is proposed as the agent for oxidation of large substrates that are too bulky to enter the active site. Here, we provide direct structural evidence, from a 2.15 Å resolution crystal structure, of (bi)carbonate captured at the active site of reduced SOD, consistent with the view that a bound carbonate intermediate could be formed, producing a diffusible carbonate radical upon reoxidation of copper. The bound carbonate blocks direct access of substrates to Cu(I), suggesting that an adjunct to the accepted mechanism of SOD catalysed dismutation of superoxide operates, with Cu(I) oxidation by superoxide being driven via a proton-coupled electron transfer mechanism involving the bound carbonate rather than the solvent. Carbonate is captured in a different site when SOD is oxidised, being located in the active site channel adjacent to the catalytically important Arg143. This is the probable route of diffusion from the active site following reoxidation of the copper. In this position, the carbonate is poised for re-entry into the active site and binding to the reduced copper. © 2012 Strange et al

Isolation and characterization of arsenite oxidizing Pseudomonas lubricans and its potential use in bioremediation of wastewater

A bacterium, Pseudomonas lubricans, isolated from heavy metal laden industrial wastewater, has been shown to tolerate multiple heavy metals suggesting its importance in bioremediation of industrial effluents. P. lubricans tolerated As(III) up to 3 mg ml-1, Cu2+ up to 0.7 mg ml-1, Hg2+ up to 0.4 mg ml-1, Ni2+ up to 0.4 mg ml-1 and Cr6+ up to 0.5 mg ml-1. P. lubricans showed optimum growth at pH 7 while optimum temperature for growth was 30°C. P. lubricans could oxidize As(III) 42% (42 μg mg-1 of protein), 78% (78 μg mg-1 of protein) and 95% (95 μg mg-1 of protein) from the medium after 24, 48 and 72 h of incubation at optimal conditions, respectively. The arsenite oxidizing ability shown by P. lubricans indicates its potential application in biological treatment of wastewaters contaminated with arsenic

Functional properties of enzymatically modified protein from fish waste

Fish flour from dried waste consisting of head, tail, fins and entrails was enzimatically hydrolysed using various proteases and the hydrolysate was spray dried. The functional properties such as water-fat absorption ratio, foaming and solubility index of the hydrolysates and fish flour revealed that some of the products might find significant uses in the food and/or cosmetics industry. Electrophoretic separation of the proteins from the fish flour and of the hydrolysates indicated that almost all the flour proteins are susceptible to proteolytic cleavage with the exception of one or two. The extent of degree of hydrolysis from 43-70.3% with a simultaneous decrease in unpleasant smell suggest an economical tool for minimizing odour pollution due to fish industry waste deterioration

Collecting Race, Ethnicity, and Language Data to Identify and Reduce Health Disparities: Perceptions of Health Plan Enrollees

Abstract available at publisher's website

Bacteria from contaminated urban and hilly areas as a source of polyhydroxyalkanoates production

Polyhydroxyalkanoates (PHA) production and extraction of different bacterial strains isolated from contaminated urban and hilly areas was conducted. The 30 bacterial isolates were Gram negative andbelonged to Pseudomonas, Citrobacter, Klebsiella, Escherichia and Enterobacter genera. Bacterial level of resistance against antibiotics (Penicillin) and heavy metals (zinc, cadmium and copper) was determined. Bacterial isolates from contaminated urban areas were found to be more resistant. The screening for PHA production was done by the Sudan black staining. Among the urban area isolates, U17, U8 and U9 produced highest concentration of PHA (50.4, 40.6 and 37.9%) while in hilly areaisolates H8, H6 and H9 showed highest production (45.8, 42.4 and 37.6%) by SDS digestion method. The percentage production was lowered when the extraction was done by sodium hypochlorite digestion method. Selected bacterial strains were optimized for PHA production at different growth conditions that is, pH, temperature and carbon sources. Bacterial isolates U8, U17 and H8 produced maximum amount of PHA 74, 69 and 59%, respectively, at pH 7, 37°C and using cooking oil as carbon source after 72 h. PHA polymerase phaC1/C2 genes were successfully amplified from genomic DNA of three bacterial isolates showing 540 bp DNA fragment which confirmed the presence of phaC1/C2 gene presence. It showed that the corresponding bacterial isolates would have been able to synthesizemedium chain length PHA

An audit of head trauma care and mortality

Objective: To analyze the factors contributing to deaths from head trauma by using standardized assessment parameters and to provide a peer-review of head injury deaths with focus on identifying deficiencies and analyzing contributory factors.Design: Descriptive study.Place and duration of study: The study was carried out at the Emergency, Aga Khan University Hospital during January 1998 to December 1999.Subjects and method: One hundred and three patients above the age of 15 years presenting alive to the Aga Khan University Hospital (AKUH) emergency with head injury were included in this study. Identified deaths data was reviewed by the Hospital Trauma Peer Review Committee and consensus arrived at for categorization of deaths. The potential deficiencies in care were identified and final recommendations made. The data was computed on CDC Trauma Registry (V 3.0) and SPSS (V 8.0).Results: Mean age was 31.9 years (n=103) with predominant male population (4:1). Severe head injury (GCS\u3c8) accounted for 21.3 % (n=22) of all cases with a total number of deaths being 12.6 % (n=13). Deaths were categorized preventable in 3 cases with non-preventable and potentially preventable in 4 and 6 cases respectively. Road traffic accidents were the predominant mechanism (n=8) in all deaths (n=13). The time interval in relation to mortality was biphasic, most deaths occurring either within 24 hours or between 3-7 days of injury. Inappropriate pre-hospital treatment, pre-hospital delays and inappropriate mode of transportation without inter-hospital communication were the process-related defects in pre-hospital care with major determinant of deaths outside AKUH (n=5). Prolonged emergency stay, delayed intensive care availability were the process-related deficiencies whereas inappropriate initial resuscitation, inappropriate initial head injury management were provider-related deficiencies in in-hospital care.Conclusion: Transfer of inappropriately managed patients, lapses in inter-hospital communications, delayed transfers were identified as the major pre-hospital factors whereas lack of ICU beds, portable ventilators in emergency room, delays in CT scan facilities were the deficiencies in the hospital services. Opportunities for improvement in head trauma care are needed to focus on initial resuscitation and appropriate surgical management

Fiscal Policy and Its Role in Reducing Income Inequality: A CGE Analysis for Pakistan

Income inequality is one of the critical barriers to growth and development in most of the developing countries including Pakistan. Every third man in Pakistan falls below the poverty line1. Moreover, the budget deficit has also been a serious issue throughout the history of Pakistan‟s economy. The persistent budget deficit is the constant source of increasing poverty and deterioration of income distribution. Since deficit is financed by increasing indirect taxes and money supply, it causes the reduction in purchasing power and leads the masses towards poverty [Arif and Farooq (2011)]. Therefore, it is a dire need of the economy to have a good public policy such that it could reduce budget deficit, alleviate poverty and redistribute income. Malik and Saqib (1985) suggest that the resources of the economy can be distributed equally only through appropriate changes in the tax system. Fiscal policy can have a significant influence on removing the gap between haves and havenots both directly and indirectly. It directly affects the disposable income of individuals, whereas affecting their future earning capacities indirectl

Characterization of Diazotrophs associated with roots of Leptochloa fusca (L) Kunth

A group of nine diazotrophs were isolated from the rhizosphere of kallar grass and cultured on nitrogent-jree medium. K 5 , Ks' K9' KlD' Kl2, K13 showed high nitrogenase activity (> 18 n mol C#4 h-I viatl) whereas in K7 and K14 it was comparatively low « 5n mol C#4 h l viatl ). Maximum nitrogenase activity was found in young cultures (after 24 hours of incubation) except for K9 and Kl3 where it was maximum after 36 and 48 h, respectively. All strains were Gram-negat, produced smooth colonies and pellicles on semi-solid media. Cells of K5, K7' KID' KlI, Kl2 and K14 were pleiomorphic: Ks formed long fine rods; K9 was small, round or oval shaped; while KI4 formed beaded rods. Only Ks' K 13 and KI4were found to be motile. All isolates were able to reduce nitrate, and were positive for oxidase an catalese. None of them could denitrify or had urease activity except for K14 which was urease positive. Ks' Kl3 and KI4 were fermentative and produced red pigments. The isolates K5, KIO and KI2 are assigned to the genus Azotobacter while others remained unidentified