An investigation on the level of some minor and trace elements in some varieties of meat (beef, mutton and chicken) consumed in Bangladesh is reported. In this study, protoninduced X-ray emission (PIXE) and radioisotope-induced X-ray fluorescence (XRF) techniques were used for analytical measurements. In PIXE measurements, the samples were exposed to the proton beam in air as 1 mm thick pellets and irradiated with 2.0 MeV protons having the beam intensity of 30 nA for characteristic X-ray excitation, whereas in XRF, the samples were excited for 5000 seconds with a 10 mCi109Cd annular X-ray source. The elemental concentrations of Ca, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Rb and Sr were determined in the samples by comparison with X-ray yield curves constructed from IAEA and NBS standard reference materials. The significance of the results is dicussed in relation to human health and diseases.
Authors:M. Ali, A. Khan, A. Wahiduzzaman and M. Malek
The trace element concentrations of eight elements (Ca, Cr, Mn, Fe, Ni, Cu, Zn and Pb) in the scalp hair of 49 normal and 55 malnourished children of the Bangladesh population, in the age group of 1 to 5 years were analyzed by the external beam PIXE method to establish their baseline values in normal children for pre-diagnostic screening of deficiency and excess in malnutrition. The results of this investigation show that the ranges of trace elements in hair are somewhat wide. For example, the normal Zn level has the range of 63–377 g·g–1 for 49 subjects. The reasons for these large individual deviations are unknown till now. The average of the elemental concentrations between normal and malnourished groups are compared (t-test,p<0.05). A correlation study has been done on each pair of original data by a non-parametric Speaman's rank test. The frequency distributions of the elements are presented and the results are compared with the data reported in the literature. A substantive correspondence between the present data in hair of both the study groups and the literature values from different countries have been observed but they did not show any regular dependence on the nutritional status of the subjects. Only the low Cu content in the hair of malnourished group can possibly be linked with nutritional disorders as evidenced from this study.
Authors:Victor Sebastian, Saif A. Khan and Amol A. Kulkarni
Continuous-flow synthesis of specific functional materials is now seen as a reliable synthesis approach that gives consistent product properties. This perspective article aims to survey recent work in some of the relevant areas and to identify new domains where flow synthesis of functional materials can be better than the conventional synthesis methods. It also emphasizes the need for developing high-throughput integrated synthesis and screening systems for almost all functional materials so that laboratory-scale recipes can be transformed into reliable manufacturing processes. New areas relevant to functional materials which have remained unexplored in flow synthesis are also highlighted.
Authors:A. Rahman, K. Khan, G. Al-Khaledi, I. Khan and Sreeja Attur
Cognitive impairment is a common feature of both lead exposure and hyperphosphorylation of tau. We, therefore, investigated whether lead exposure would induce tau hyperphosphorylation. Wistar rat pups were exposed to 0.2% lead acetate via their dams’ drinking water from postnatal day 1 to 21. Lead in blood and brain were measured by atomic absorption spectrophotometry and the expression of tau, phosphorylated tau and various serine/threonine protein phosphatases (PP1, PP2A, PP2B and PP5) in the brain was analyzed by Western blot. Lead exposure significantly impaired learning and resulted in a significant reduction in the expression of tau but increased the phosphorylation of tau at Ser199/202, Thr212/Ser214 and Thr231. PP2A expression decreased, whereas, PP1 and PP5 expression increased in lead-exposed rats. These results demonstrate that early postnatal exposure to lead decrease PP2A expression and induce tau hyperphosphorylation at several serine and threonine residues. Hyperphosphorylation of tau may be a mechanism of Pb-induced deficits in learning and memory.
Authors:A. Rehman, M. Sajjad, S.H. Khan, R.J. Peña and N.I. Khan
The allelic variation for Glu-1, Glu-3 loci and presence of IBL-1RS translocation was determined in 126 spring wheat accessions. The most common alleles at Glu-1 loci were Glu-A1b (59.52%), Glu-B1c (41.26%), and Glu-D1d (57.14%) and at Glu-3 loci were Glu-A3c (56.45%), Glu-B3j (29.36%), and Glu-D3b (76.98%). Modern Pakistani wheat varieties carried superior alleles at Glu-1 and Glu-3 loci for bread-making quality and had no negative influence of secalin protein-synthesized by 1BL-1RS translocation. For LMW-GS, the most common combination was Glu-A3c, Glu-B3j and Glu-D3b. The loci Glu-B1 and Glu-B3 had the highest allelic diversity of Glu-1 and Glu-3 loci, respectively.
Authors:Nadeem Musahwar, Wasi Khan, M. Husain, M. Zulfequar and M. A. Majeed Khan
In the present study samples of Se100 − xSx has been prepared by conventional melt-quenching technique in the composition range 5 ≤ x ≤ 20 (at.%). The crystallization process in glassy system was investigated under non-isothermal condition using differential scanning calorimetry (DSC) at 5, 10, 15, and 20 °C/min heating rates (φ). The DSC traces have been analyzed in terms of activation energy (ΔEc) and Avrami exponent (n) using different models viz. the Starink, Flynn–Wall–Ozawa, the Friedman–Ozawa, Kissinger–Akahira–Sunose equations. The composition dependence on the glass transition temperature (Tg), the crystallization temperature (Tc), and the peak temperatures (Tp) of the samples were also determined. The analysis shows that the incorporation of sulfur content has a strong influence on the crystallization mechanism for the Se–S glassy system.
Authors:Z. Chaudhry, H. Khan, K. Khan, M. Aslam, A. Jabbar and S. Orfi
Specific activity of natural radionuclides; 226Ra, 232Th and 40K were measured in the agricultural soil of eastern salt range of Pakistan using gamma ray spectrometry. The soil samples were collected within the ploughing region (up to 12 cm depth) and processed before analysis. The average specific activities of different radionuclides in the dry mass of soil samples were: 40K, (666 Bq/kg), 226Ra (51 Bq/kg), and 232Th (59 Bq/kg). The average outdoor terrestrial absorbed dose rate in air from gamma radiation one meter above ground surface was found to be 93 nGy/h.
Authors:A. Khan, H.H. Liu, A. Ahmad, L. Xiang, W. Ali, A. Khan, M. Kamran, S. Ahmad and J.C. Li
Higher plant population and nitrogen management is an adopted approach for improving crop productivity from limited land resources. Moreover, higher plant density and nitrogen regimes may increase the risk of stalk lodging, which is a consequence of complex interplant competition of individual organs. Here, we aimed to investigate the dynamic change in morphology, chemical compositions and lignin promoting enzymes of the second basal inter-nodes altering lodging risk controlled by planting density and nitrogen levels. A field trial was conducted at the Mengcheng research station (33°9′44″N, 116°32′56″E), Huaibei plain, Anhui province, China. A randomized complete block design was adopted, in which four plant densities, i.e., 180, 240, 300, and 360 × 104 ha−1 and four N levels, i.e., 0, 180, 240, and 300 kg ha−1 were studied. The two popular wheat varieties AnNong0711 and YanNong19 were cultivated. Results revealed that the culm lodging resistance (CLRI) index of the second basal internodes was positively and significantly correlated with light interception, lignin and cellulose content. The lignin and cellulose contents were significantly and positive correlated to light interception. The increased planting density and nitrogen levels declined the lignin and its related enzymes activities. The variety AnNong0711 showed more resistive response to lodging compared to YanNong19. Overall our study found that increased planting densities and nitrogen regimes resulted in poor physical strength and enzymatic activity which enhanced lodging risk in wheat varieties. The current study demonstrated that stem bending strength of the basal internode was significantly positive correlated to grains per spike. The thousand grain weight and grain yield had a positive and significant relationship with stem bending strength of the basal internode. The results suggested that the variety YanNong19 produces higher grain yield (9298 kg ha−1) at density 240 × 104 plants ha−1, and 180 kg ha−1 nitrogen, while AnNong0711 produced higher grain yield (10178.86 kg ha−1) at density 240 × 104 plants ha−1 and with 240 kg ha−1 nitrogen. Moreover, this combination of nitrogen and planting density enhanced the grain yield with better lodging resistance.
Most agronomic soils contain large reserves of total phosphorus [P], but the fixation and precipitation of P cause P deficiency, and in turn, restrict the growth of crops severely. Phosphorus replenishment, especially in sustainable production systems, remains a major challenge as it is mainly fertilizer-dependent. Though the use of chemical P fertilizers is obviously the best means to circumvent P deficiency in different agro-ecosystems, their use is always limited due to its spiralling cost. A greater interest has, therefore, been generated to find an alternative yet inexpensive technology that could provide sufficient P to plants while reducing the dependence on expensive chemical P fertilizers. Among the heterogeneous and naturally abundant microbes inhabiting the rhizosphere, the phosphate solubilizing microorganisms (PSM) including bacteria have provided an alternative biotechnological solution in sustainable agriculture to meet the P demands of plants. These organisms in addition to providing P to plants also facilitate plant growth by other mechanisms. Despite their different ecological niches and multiple functional properties, P-solubilizing bacteria have yet to fulfil their promise as commercial bio-inoculants. Current developments in our understanding of the functional diversity, rhizosphere colonizing ability, mode of actions and judicious application are likely to facilitate their use as reliable components in the management of sustainable agricultural systems.
Authors:S. Ahmad, A. Mannan, I. Qureshi, S. Khan and I. Ahmad
A rapid and simple method for the determination of iodine from water has been described which is based on preconcentration of iodine with 0.1M solution of 4-(5-nonylpyridine) in benzene or carbon tetrachloride from 1–2M HNO3 followed by neutron irradiation and gamma-ray activity measurements. A clinical survey of endemic goitrous area has also been made to find a possible correlation between the endemic goiter and iodine deficiency in water.