Geological and hydrogeological investigations in west Malaysia

The author has identified the following significant results. Large structures along the east coast of the peninsula were discovered. Of particular significance were the circular structures which were believed to be associated with mineralization and whose existence was unknown. The distribution of the younger sediments along the east coast appeared to be more widespread than previously indicated. Along the Pahang coast on the southern end, small traces of raised beach lines were noted up to six miles inland. The existence of these beach lines was unknown due to their isolation in large coastal swamps

Ab-initio study of the bandgap engineering of Al(1-x)Ga(x)N for optoelectronic applications

A theoretical study of Al(1-x)Ga(x)N, based on full-potential linearized augmented plane wave method, is used to investigate the variations in the bandgap, optical properties and non-linear behavior of the compound with the variation of Ga concentration. It is found that the bandgap decreases with the increase of Ga in Al(1-x)Ga(x)N. A maximum value of 5.5 eV is determined for the bandgap of pure AlN which reaches to minimum value of 3.0 eV when Al is completely replaced by Ga. The static index of refraction and dielectric constant decreases with the increase in bandgap of the material, assigning a high index of refraction to pure GaN when compared to pure AlN. The refractive index drops below 1 for photon energies larger than 14 eV results group velocity of the incident radiation higher than the vacuum velocity of light. This astonishing result shows that at higher energies the optical properties of the material shifts from linear to non-linear. Furthermore, frequency dependent reflectivity and absorption coefficients show that peak value of the absorption coefficient and reflectivity shifts towards lower energy in the UV spectrum with the increase in Ga concentration. This comprehensive theoretical study of the optoelectronic properties of the alloys is presented for the first time which predicts that the material can be effectively used in the optical devices working in the visible and UV spectrum.Comment: 18 pages, 7 figure

Annealing-induced Fe oxide nanostructures on GaAs

We report the evolution of Fe oxide nanostructures on GaAs(100) upon pre- and post-growth annealing conditions. GaAs nanoscale pyramids were formed on the GaAs surface due to wet etching and thermal annealing. An 8.0-nm epitaxial Fe film was grown, oxidized, and annealed using a gradient temperature method. During the process the nanostripes were formed, and the evolution has been demonstrated using transmission and reflection high energy electron diffraction, and scanning electron microscopy. These nanostripes; exhibited uniaxial magnetic anisotropy. The formation of these nanostructures is attributed to surface anisotropy, which in addition could explain the observed uniaxial magnetic anisotropy

Antigenotoxic and anticlastogenic potential of Agaricus bisporus against MMS induced toxicity in human lymphocyte cultures and in bone marrow cells of mice

The aim of the present study is to evaluate, for the first time, antigenotoxic potential of Agaricus bisporus against methyl methanesulphonate induced toxicity in human lymphocyte culture in vitro and in bone marrow cells of albino mice in vivo. The parameters studied included total aberrant cells and the frequencies of aberrations in the bone marrow cells at three exposure durations viz., 16, 24 and 32 h, and for the in vitro method using chromosomal aberrations, sister chromatid exchanges and replication indices as markers. The alcoholic extract of A. bisporus was taken in five increasing concentrations of 200, 250, 300, 350 and 400 mg/kg body weight for three in vivo exposure durations viz., 16, 24 and 32 h. Similarly, four doses of extracts viz., 150, 200, 250 and 300 lg/ ml of culture were taken for in vitro durations of 24, 48 and 72 h in the presence as well as the absence of S9-mix. The treatment reduced the total number of aberrant cells ranging from 10.0% to 46.15% and it reduced the total frequencies of aberrations ranging from 198 to 96 against very high aberrations i.e., 227 caused due to methyl methanesulphonate in vivo. The same trends were observed in the in vitro experiments i.e., it reduced chromosomal aberrations from (42.00%, 71.25%, and 83.00% to 20.00%, 39.50%, and 43.00%) at 24, 48, and 72 h of exposure respectively. However when experiments were carried out in the presence of liver S9 fraction, these values were respectively 52.38, 44.56, and 48.34% significant at <0.05 level, likewise it also reduced sister chromatid exchanges from 14.86 ± 1.44 down to 8.84 ±0.75 per cell, whereas the replication index got enhanced from 1.45 to 1.64

Transverse Momentum Distribution and Elliptic Flow of Charged Hadrons in UU+UU collisions at sNN=193\sqrt{s_{NN}}=193 GeV using HYDJET++

Recent experimental observations of the charged hadron properties in $U+U$ collisions at $193$ GeV contradict many of the theoretical models of particle production including two-component Monte Carlo Glauber model. The experimental results show a small correlation between the charged hadron properties and the initial geometrical configurations (e.g. body-body, tip-tip etc.) of $U+U$ collisions. In this article, we have modified the Monte Carlo HYDJET++ model to study the charged hadron production in $U+U$ collisions at $193$ GeV center-of-mass energy in tip-tip and body-body initial configurations. We have modified the hard as well as soft production processes to make this model suitable for $U+U$ collisions. We have calculated the pseudorapidity distribution, transverse momentum distribution and elliptic flow distribution of charged hadrons with different control parameters in various geometrical configurations possible for $U+U$ collision. We find that HYDJET++ model supports a small correlation between the various properties of charged hadrons and the initial geometrical configurations of $U+U$ collision. Further, the results obtained in modified HYDJET++ model regarding $dn_{ch}/d\eta$ and elliptic flow ($v_{2}$) suitably matches with the experimental data of $U+U$ collisions in minimum bias configuration.Comment: 29 pages, 25 figures. Accepted for Publication in EPJ

Event by Event Analysis of High Multiplicity Events Produced in 158 A GeV/c 208 Pb- 208 Pb Collisions

An extensive analysis of individual high multiplicity events produced in 158 A GeV /c 208Pb- 208Pb collisions is carried by adopting different methods to examine the anomalous behavior of these rare events. A method of selecting the events with densely populated narrow regions or spikes out of a given sample of collision events is discussed.Employing this approach two events with large spikes in their eta- and phi- distributions are selected for further analysis. For the sake of comparison, another two events which do not exhibit such spikes are simultaneously analyzed. The findings suggest that the systematic studies of particle density fluctuations in one- and two-dimensional phase-spaces and comparison with those obtained from the studies of correlation free Monte Carlo events, would be useful for identifying the events with large dynamical fluctuations. Formation of clusters or jet like phenomena in multihadronic final states in individual events is also discussed and the experimental findings are compared with the independent particle emission hypothesis by carrying out Monte Carlo simulations

Correlation of Atrial Fibrillation with Left Atrial Volume in Patients with Mitral Stenosis. a Single Centre Study From Pakistan

Background: Rheumatic heart disease has a strong association with mitral valve stenosis. Atrial fibrillation is one of the most common complications of this condition and is a poor prognostic factor. Early detection and prompt management of atrial fibrillation can help to improve the quality of life and increase the life expectancy of the patients. We carried out this study to investigate the significance of left atrial volumetric changes in mitral stenosis and its correlation with atrial fibrillation. Methodology: We audited the data of 60 patients of rheumatic heart disease who had mitral valve stenosis. The patients were randomized into atrial fibrillation (Group A) and normal sinus rhythm (Group B). We conducted this cross-sectional analytical study at Cardiology Department, Mayo Hospital, Lahore, from 1st February 2017 to 31st January 2018. We only included those patients who consented to be a part of this study and fulfilled our predefined inclusion criteria. Left atrial volume was measured by prolate ellipse method and biplane methods on echocardiography. The Data was analyzed on SPSS v20. Results: Sixty patients were included in the study. Among the subjects, thirty-six (60%) were males, and twenty-four (40%) were females. Atrial fibrillation was noted in 43.33% of the patients of mitral valve stenosis. There was a marked difference in the mean volume of the left atrium among the two groups. We observed that the mean area of the mitral valve for Group A patients was larger than that of patients in Group B. Our study showed an inverse correlation between left atrial volume and mitral valve area among Group A patients. Conclusion: Patients of mitral stenosis are at an increased risk of developing atrial fibrillation if the left atrial volume is increasing. All patients with mitral stenosis should have routine echocardiography & measurement of left atrial volumes, so that proper treatment can be started if the left atrial volume is increasing, to prevent atrial fibrillation

High Performance Anticorrosive Polyester Coatings on Mild Steel In Mixed Acid Mixtures Environments

Anticorrosive polyester based composite coatings on mild steel applied to mixed acid storage tank containing varying compositions of Sulfuric Acid, Nitric acid provide anticorrosive solutions. These coatings are capable to inhibit the redox reactions. In consideration of above, the purpose of present work is to prevent corrosion on mixed acid storage tank through application of appropriate polyester coatings on their surface and structures that will be used in chemical industries where these acids are being stored. In this project, the surface of mild steel was coated by protective polymer coatings. Lab scale storage tanks of mild steel were coated with anticorrosive (fiber reinforced laminate-vinyl and fiber reinforced laminate palatal p-4). Various coatings compositions were explored based on esters. Electrochemical Impedance Spectroscopy (EIS), Gamry Potentiostat Tafel Scan analyses tools were used and Scanning Electron Microscopy (SEM) was conducted to investigate the surface morphology of these coatings. The applied polymer based composite coatings provided excellent corrosion resistance in both Laminate palatal fiber reinforced (LAM-P/FR) and laminate vinyl fiber reinforced (LAM-V/FR) coatings condition and reduction in corrosion rate. These bespoke coatings can be widely used to protect mild steel structures which are usually acid storage tanks and are used in various chemical industries with acidic environment. The study estimated that 25 to 30% of annual corrosion costs could be saved as well as production increases if these corrosion protection coatings were employed