Nature of band-gap states in V-doped TiO2 revealed by resonant photoemission

Band-gap states in V-doped TiO2 have been studied by photoemission spectroscopy over a range of photon energies encompassing the Ti 3p and V 3p core thresholds. The states show resonant enhancement at photon energies significantly higher than found for Ti 3d states introduced into TiO2 by oxygen deficiency or alkalimetal adsorbates. This demonstrates that the gap states relate to electrons trapped on dopant V cations rather than host Ti cations

Butyrylcholinesterase activity in Nigerian type 2 diabetics with and without metabolic syndrome

Type 2 diabetes mellitus is a chronic progressive disease typified by a loss of glycaemic control over time as the insulin secreting pancreatic -cells lose their ability to compensate for the prevailing levels of insulin sensitivity. Several abnormalities are associated with diabetes and metabolic syndrome. Butyrylcholinesterase activity in diabetes and metabolic syndrome is generally under reported. Blood samples and demographic data were obtained from one hundred and five patients presenting atSpecialist Hospital Sokoto, Nigeria. These were screened for type 2 diabetes according to the guidelines of the American Diabetes Association. Based on anthropometric indices and clinical data, patients were stratified into to 4 groups: Control (n = 44), type 2 diabetics with metabolic syndrome (n = 14), obese type 2 diabetics without metabolic syndrome (n = 21) and non-obese type 2 diabetics without metabolic syndrome (n = 26). Butyrylcholinesterase was assayed by kinetic and colorimetric method,other biochemical and clinical parameters were according to standard methods. Type 2 diabetics with or without metabolic syndrome have significantly higher activity of butyrylcholinesterase than controlgroup. The higher activity of the enzyme may have been influenced by hyperglycemia, obesity and metabolic syndrome through enhanced transcription or catalytic mechanism of the enzyme or both.Butyrylcholinesterase activity may serve as marker to predict the development of type 2 diabetes and or metabolic syndrome

Preliminary Investigation on In Vivo Trypanocidal Activity of Hydroethanolic Extracts of Calotropis procera and Parkinsonia aculeata

Effect of extracts of Calotropis procera and Parkinsonia aculeata in the treatment of Trypanosoma brucei brucei infected rats was studied. The albino rats were treated for 7 days with 200mg of the plant extracts intraperitoneally (ip) after establishment of parasitaemia. No significant(p>0.05) changes in weights were observed in all the groups. The results showed that Calotropis procera (root) was 96.43% as effective as Diminazene aceturate (berenil) in clearing parasitaemia. Significant(p<0.05) improvements in parked cell volume (PCV) were observed in the rats treated with Calotropis procera (root) and berenil. However, Calotropis procera (leaf) and Parkinsonia aculeata (leaf and stem bark) depressed red blood cell production. Total white blood cells (WBC) and differential count did not change significantly (p>0.05) in Calotropis procera (root) and berenil (positive control drug) treated groups. These observations were reversed in leaf and stem bark and leaf extracts of Calotropis proceraand Parkinsonia aculeata, respectively. In conclusion only the root extracts of Calotropis procera has demonstrated effective treatment of  trypanosomiasis, possibly due to its phytochemical contents.Key words: <i>Parkinsonia aculeata, Calotropis procera, Trypanosoma brucei brucei</i>, Haematological parameter

Study on the conformation of insulin by solvent perturbation and ultraviolet spectroscopy

This study attempted to gain an insight of the conformation of insulin using solvent perturbation and ultraviolet spectroscopy. The effects of two solvents, mercaptoethanol and sucrose on the absorption spectrum of Insulin were studied; changes in ionic strength and pH were used to  identify the position of amino acid chromophores. The effect on the absorption spectrum of movement from a non-polar to a polar  environment indicates that tyrosine and phenylalanine reside on the surface of insulin protein. The results show that pH resolved spectral behavior of Insulin in the neighborhood of 290 nm is determined  predominantly by the ionization of imidazole – NH+ of histidine. The results, however, do not rule out the possible contribution of the phenol hydroxyl of tyrosine in the spectral behavior. © 2013 International Formulae Group. All rights reserved.Keywords: Insulin conformation, solvent perturbation, ultraviolet spectroscopy

Effect of Guanidium Hydrochloride on the Stability of Horse Skeletal Muscle Myoglobin

The stability of the three dimensional structure of horse skeletal muscle myoglobin was investigated using visible spectroscopy. Guanidium hydrochloride (GuHCl) of concentrations 0.4 – 0.8M have no observable effect on the three dimensional structure as indicated by monitoring the absorbance at 420nm. However, higher concentrations (1.0-3.0M) resulted in unfolding of the protein as indicated by the dip in absorption from 0.535 to 0.350.The requirement for high denaturant concentration to perturb the structure of myoglobin indicates the high stability of the protein. We conclude that high concentrations of the denaturant GuHCl, disrupts the 3-dimensional structure of myoglobin causing its unfolding, in a two- state process, due to weak binding to the protein, which can be studied spectrophotometricall

The temperature and entropy of CFT on time-dependent backgrounds

We express the AdS-Schwarzschild black-hole configuration in coordinates such that the boundary metric is of the FLRW type. We review how this construction can be used in order to calculate the stress-energy tensor of the dual CFT on the FLRW background. We deduce the temperature and entropy of the CFT, which are related to the temperature and entropy of the black hole. We find that the entropy is proportional to the area of an apparent horizon, different from the black-hole event horizon. For a dS boundary we reproduce correctly the intrinsic temperature of dS space.Comment: 19 pages, major revision, several comments added, version to appear in JHE

A nuclear magnetic resonance study of water in aggrecan solutions

Aggrecan, a highly-charged macromolecule found in articular cartilage, was investigated in aqueous salt solutions with proton Nuclear Magnetic Resonance. The longitudinal and transverse relaxation rates were determined at two different field strengths, 9.4 T and 0.5 T, for a range of temperatures and aggrecan concentrations. The diffusion coefficients of the water molecules were also measured as a function of temperature and aggrecan concentration, using a pulsed field gradient technique at 9.4 T. Assuming an Arrhenius relationship, the activation energies for the various relaxation processes and the translational motion of the water molecules were determined from temperature dependencies as a function of aggrecan concentration in the range 0 – 5.3 % w/w. The longitudinal relaxation rate and inverse diffusion coefficient were approximately equally dependent on concentration and only increased by ≤ 20% from that of the salt solution. The transverse relaxation rate at high field demonstrated greatest concentration dependence, changing by an order of magnitude across the concentration range examined. We attribute this primarily to chemical exchange. Activation energies appeared to be approximately independent of aggrecan concentration, except for that of the low-field transverse relaxation rate, which decreased with concentration

Interdisciplinary approaches to metastasis

Interdisciplinary research is making a significant contribution to understanding metastasis - one of the grand challenges in cancer research. Examples drawn from apparently unconnected areas of physics, and described at a recent workshop on metastasis, illustrate the value of interdiscplinary thinking

Qunatification of Metabolites in MR Spectroscopic Imaging using Machine Learning

Magnetic Resonance Spectroscopic Imaging (MRSI) is a clinical imaging modality for measuring tissue metabolite levels in-vivo. An accurate estimation of spectral parameters allows for better assessment of spectral quality and metabolite concentration levels. The current gold standard quantification method is the LCModel - a commercial fitting tool. However, this fails for spectra having poor signal-to-noise ratio (SNR) or a large number of artifacts. This paper introduces a framework based on random forest regression for accurate estimation of the output parameters of a model based analysis of MR spectroscopy data. The goal of our proposed framework is to learn the spectral features from a training set comprising of different variations of both simulated and in-vivo brain spectra and then use this learning for the subsequent metabolite quantification. Experiments involve training and testing on simulated and in-vivo human brain spectra. We estimate parameters such as concentration of metabolites and compare our results with that from the LCModel

Emplacement of inflated Pāhoehoe flows in the Naude’s Nek Pass, Lesotho remnant, Karoo continental flood basalt province: use of flow-lobe tumuli in understanding flood basalt emplacement

Physical volcanological features are presented for a 710-m-thick section, of the Naude’s Nek Pass, within the lower part of the Lesotho remnant of the Karoo Large Igneous Province. The section consists of inflated pāhoehoe lava with thin, impersistent sedimentary interbeds towards the base. There are seven discreet packages of compound and hummocky pāhoehoe lobes containing flow-lobe tumuli, making up approximately 50% of the section. Approximately 45% of the sequence consists of 14 sheet lobes, between 10 and 52-m-thick. The majority of the sheet lobes are in two packages indicating prolonged periods of lava supply capable of producing thick sheet lobes. The other sheet lobes are as individual lobes or pairs, within compound flows, suggesting brief increases in lava supply rate. We suggest, contrary to current belief, that there is no evidence that compound flows are proximal to source and sheet lobes (simple flows) are distal to source and we propose that the presence of flow-lobe tumuli in compound flows could be an indicator that a flow is distal to source. We use detailed, previously published, studies of the Thakurvadi Formation (Deccan Traps) as an example. We show that the length of a lobe and therefore the sections that are ‘medial or distal to source’ are specific to each individual lobe and are dependent on the lava supply of each eruptive event, and as such flow lobe tumuli can be used as an indicator of relative distance from source