Boobalan G.,Annamalai University |
Imran P.K.M.,Islamia College |
Manoharan C.,Annamalai University |
Nagarajan S.,Central University of Tamil Nadu
Journal of Electronic Materials | Year: 2015
Perylene diimides with high photosensitivity and high electron mobility have attracted much attention for use in organic semiconductor devices. In this investigation, thin films of six new perylene tetracarboxylic diimides (PTCDI) were fabricated by spin coating, on glass as substrate, and their optical and electrical properties were studied. The absorption spectra of thin films of PTCDI furnished more informative bands than those of the compounds in solution. The morphology of the thin films was examined by scanning electron microscopy and x-ray diffraction. The absorption spectra and I–V characteristics of the compounds were affected by their molecular structures. HOMO–LUMO band gaps of the films were in the range 1.9–2.0 eV. Band gaps calculated by use of computational methods were comparable with experimental results. © 2015, The Minerals, Metals & Materials Society.
Nurul Haque Mollah Md.,The Institute of Statistical Mathematics of Tokyo |
Nurul Haque Mollah Md.,University of Rajshahi |
Sultana N.,Islamia College |
Minami M.,Keio University |
And 2 more authors.
Neural Networks | Year: 2010
This paper discusses a new highly robust learning algorithm for exploring local principal component analysis (PCA) structures in which an observed data follow one of several heterogeneous PCA models. The proposed method is formulated by minimizing β-divergence. It searches a local PCA structure based on an initial location of the shifting parameter and a value for the tuning parameter β. If the initial choice of the shifting parameter belongs to a data cluster, then the proposed method detects the local PCA structure of that data cluster, ignoring data in other clusters as outliers. We discuss the selection procedures for the tuning parameter β and the initial value of the shifting parameter μ in this article. We demonstrate the performance of the proposed method by simulation. Finally, we compare the proposed method with a method based on a finite mixture model. © 2009 Elsevier Ltd. All rights reserved.
Manan A.,University of Science & Technology Bannu |
Ullah I.,University of Science & Technology Bannu |
Ahmad A.S.,Islamia College |
Ullah A.,Wuhan University of Technology
Journal of Materials Science: Materials in Electronics | Year: 2016
Ca1-xBaxLa4Ti5O17 (0 ≤ x ≤ 0.2) compositions were fabricated via a solid-state mixed oxide route and their phase, microstructure and microwave dielectric properties were investigated. All the compositions formed single phase in the Ca1-xBaxLa4Ti5O17 (0 ≤ x ≤ 0.2) solid solutions within the detection limit of in-house X-ray diffraction. The sintered microstructure of these ceramics comprised densely packed elongated and plate-like grains. The dielectric properties varied linearly with increasing x content. Relative permittivity (εr) increased from 53.2 to 56.6, Qufo decreased from 14,600 to 12,630 GHz and τf was tuned through zero and increased from -33.6 to 1.4 ppm/ºC with increase in x value from 0 to 0.2. In the present study, εr≈ 56.6, Qufo≈ 12,630 GHz and a near zero τf ≈ 1.4 ppm/ºC was achieved for Ba0.2Ca0.80La4Ti5O17(x = 0.2) ceramics. © Springer Science+Business Media New York 2016.
PubMed | Islamia College, Hazara University and University of Malakand
Type: | Journal: BioMed research international | Year: 2015
The contamination of aquatic systems with heavy metals is affecting the fish population and hence results in a decline of productivity rate. River Kabul is a transcountry river originating at Paghman province in Afghanistan and inters in Khyber Pakhtunkhwa province of Pakistan and it is the major source of irrigation and more than 54 fish species have been reported in the river. Present study aimed at the estimation of heavy metals load in the fish living in River Kabul. Heavy metals including chromium, nickel, copper, zinc, cadmium, and lead were determined through atomic absorption spectrophotometer after tissue digestion by adopting standard procedures. Concentrations of these metals were recorded in muscles and liver of five native fish species, namely, Wallago attu, Aorichthys seenghala, Cyprinus carpio, Labeo dyocheilus, and Ompok bimaculatus. The concentrations of chromium, nickel, copper, zinc, and lead were higher in both of the tissues, whereas the concentration of cadmium was comparatively low. However, the concentration of metals was exceeding the RDA (Recommended Dietary Allowance of USA) limits. Hence, continuous fish consumption may create health problems for the consumers. The results of the present study are alarming and suggest implementing environmental laws and initiation of a biomonitoring program of the river.
PubMed | Islamia College, Sudan University of Science and Technology, Shaheed Benazir Bhuto University Sheringal and Kohat University of Science and Technology
Type: Journal Article | Journal: Journal of ethnobiology and ethnomedicine | Year: 2016
Medicinal flora plays a vital role in treating various types of ailments in living beings. The present study was planned to investigate and document systematically the indigenous knowledge in a scientifically little explored area of Ladha sub-division, South Waziristan agency, Pakistan. Hence, this study would contribute positively to the field of ethnopharmacology.Prior to ethnomedicinal data collection, regular field visits were conducted during the month of May and June 2015 to locate the sites and respondents from where the traditional knowledge was to be recorded. Ethno-medicinal data was collected during the month July and August 2015 through rapid appraisal approach (RAA) based on direct interaction with the indigenous communities by making group discussions, corner meetings and semi-structured interviews. Data was evaluated statistically by using the index of Use value (UV) and Frequency of citations (FC).A total of 82 medicinal plants belonging to 42 families were reported in the study. Leaves were the most frequently used plant parts. Highest use values were recorded for Peganum harmala (0.93), Punica granatum (0.91), Thymus mongolicus (0.90), Chenopodium album (0.89), Coriandrum sativum (0.87), Mentha longifolia (0.87), Lactuca serriola (0.87) and Portulaca oleracea (0.87). Medicinal plants used for the gastro intestinal complexities and respiratory diseases were more than 9% followed by skin and diarrhea (7% each), liver disorders (5%) cough and cold fever (5%).People of the area mostly still rely on traditional herbal therapies. Keeping in mind the dependence of the indigenous community for their primary health care on such herbal remedies, pharmacological and critical toxicological investigation of certain flora is necessary. Moreover, projects should be designed to analyze the existing issues and problems related with medicinal plants conservation.
Ellison A.M.,Harvard University |
Barker Plotkin A.A.,Harvard University |
Khalid S.,Harvard University |
Khalid S.,Islamia College
Forests | Year: 2016
Eastern hemlock (Tsuga canadensis) is a foundation species in eastern North American forests. Because eastern hemlock is a foundation species, it often is assumed that the diversity of associated species is high. However, the herbaceous layer of eastern hemlock stands generally is sparse, species-poor, and lacks unique species or floristic assemblages. The rapidly spreading, nonnative hemlock woolly adelgid (Adelges tusgae) is causing widespread death of eastern hemlock. Loss of individual hemlock trees or whole stands rapidly leads to increases in species richness and cover of shrubs, herbs, graminoids, ferns, and fern-allies. Naively, one could conclude that the loss of eastern hemlock has a net positive effect on biodiversity. What is lost besides hemlock, however, is landscape-scale variability in the structure and composition of the herbaceous layer. In the Harvard Forest Hemlock Removal Experiment, removal of hemlock by either girdling (simulating adelgid infestation) or logging led to a proliferation of early-successional and disturbance-dependent understory species. In other declining hemlock stands, nonnative plant species expand and homogenize the flora. While local richness increases in former eastern hemlock stands, between-site and regional species diversity will be further diminished as this iconic foundation species of eastern North America succumbs to hemlock woolly adelgid. © 2016 by the authors.
Rehman M.-U.,Islamia College |
Imran M.,Quaid-i-Azam University |
Zia-Ur-Rehman,Quaid-i-Azam University |
Hassan A.,Quaid-i-Azam University |
And 4 more authors.
Journal of Coordination Chemistry | Year: 2015
Bis(4-benzylpiperazine-1-carbodithioato-k2 S,S′)nickel(II), 1, was prepared by metathesis of sodium salt of 4-benzylpiperazine-1-carbodithioate with nickel(II) chloride in 2: 1 ratio. Complex 1 was characterized by analytical techniques including elemental analysis, FT-IR, UV-visible spectroscopy, and X-ray single-crystal analysis. The latter technique confirmed square-planar geometry around Ni with the formation of NiS4 core with two shorter and two longer Ni-S bonds. The packing diagram revealed a supramolecular chain structure mediated by unconventional HH dihydrogen bonds that resulted in a chair and a ladder-like structure when viewed along the a-axis and c-axis, respectively. The thin-film coating resulted in a microporous film with a band gap of 1.69 eV. Complex 1-based sensor was fabricated to check the humidity-sensing properties of the material. Resistance of the device decreased by two orders of magnitude and capacitance was enhanced with the increase of relative humidity. The DNA binding study proved 1 to be a good DNA binder with binding constant value of 1.4 × 104 M-1. © 2014 Taylor & Francis.
Akhtar N.,Islamia College |
Akhtar N.,University of Gottingen |
Bergmeier E.,University of Gottingen
Pakistan Journal of Botany | Year: 2015
The variation in species richness and diversity of trees, shrubs and herbs in the mountains of Miandam, Swat, North Pakistan, along an elevation gradient between 1600 m and 3400 m was explored. Field data were collected in 18 altitudinal intervals of 100 m each. Polynomial regression was used to find relations of the different growth forms with elevation. The Shannon index was used for calculating α -diversity and the Simpson index for β-diversity. Species richness and α-diversity of herbs were unrelated to elevation. Herbaceous species turnover was high, ranging between 0.46 and 0.89, with its maximum between 2700 and 3000 m. Hump-shaped relationship was observed for shrubs with maximum richness between 2000 and 2200 m; and α -diversity decreased monotonically. Turnover of shrub species was highest between 2000 and 2500 m. Tree species richness was highest at low elevations, and α -diversity was relatively low along the entire gradient. Tree species turnover was also high in the lower zone and again at 2600-2800 m. Species richness of all vascular plants was highest at 2200-2500 m, and α - diversity was highest in the lower part of the gradient. Beta diversity of all growth forms was quite high ranging between 0.53 and 0.87along the entire gradient reflecting high species and structural turnover. © 2015, Pakistan Botanical Society. All rights reserved.
Ahmad S.,Islamia College |
Ahmad S.,University of Peshawar |
Iqbal Y.,University of Peshawar
Journal of Ceramic Processing Research | Year: 2016
Clay brick is one of the oldest and commonly used clay products in construction industry in Khyber Pakhtunkhwa (KP) Pakistan. In spite of its widespread use, studies regarding the manufacturing standards and quality of locally made bricks are much less in comparison to those of technologically advanced countries. The aim of the present study was to investigate the chemistry and phase constitution of the raw materials used in local brick kilns. Phase and microstructural analyses of fired bricks from local kilns were performed and compared with those of the laboratory made bricks. X-ray diffraction of raw materials revealed the presence of illite, quartz, clinochlore and albite while calcite was identified as a minor phase in all the investigated samples. Diopside, anorthite and quartz were observed as major phases in the kiln-fired samples, and only diopside and quartz in the laboratory-fired samples. The presence of albite and clinochlore, although in small concentrations, in the kiln-fired samples indicated that the employed temperature was too low to completely dissolve the initial ingredients. Consistent with X-ray diffraction results, semi-quantitative energy dispersive spectroscopy revealed the presence of silicon, aluminum, calcium, magnesium, iron and potassium along with a small amount of sodium in these samples. An increase in firing temperature decreased porosity which resulted in substantial increase in compressive strength and decrease in water absorption. The optimum mechanical properties were achieved at 1000 °C. © 2016, Hanyang University. All rights reserved.
Rahman M.-U.,Islamia College |
Nabi J.-U.,Ghulam Ishaq Khan Institute of Engineering Sciences and Technology
Astrophysics and Space Science | Year: 2014
Charge-changing transitions, commonly referred to as Gamow-Teller (GT) transitions, and electron capture/β+-decay strengths for pf-shell nuclei with Tz=−2 at proton drip-line have been calculated using the proton-neutron quasi-particle random phase approximation (pn-QRPA) model. The total GT+ strength values and electron capture/β+-decay rates are needed for the study of the late stages of the stellar evolution. The pn-QRPA theory is used for a microscopic calculation of GT strength distribution functions and associated stellar electron capture/β+-decay rates of proton-rich pf-shell nuclei with Tz=−2 in the mass range 46≤A≤56 at proton drip-line. Standard quenching factor of 0.74, usually implemented in the shell model calculation, has been incorporated for the comparison with experimental data (wherever available). The calculated GT strength of the two proton-rich nuclei, 52Ni and 56Zn are compared with experimental data of corresponding mirror nuclei. It has been found that the pn-QRPA results are in good agreement with the experimental data as well as shell model result. It is noted that the total GT strength increases linearly with the increase of mass number. The electron capture/β+-decay rates for proton-rich nuclei are calculated on a temperature and density scale relevant to presupernova evolution of massive stars. The β+ decay half-lives are compared with measured and other theoretical calculations. © 2014, Springer Science+Business Media Dordrecht.