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Open access

M. Arshad Javid, M. Rafi, Ihsan Ali, Fayyaz Hussain, M. Imran and Ali Nasir

Abstract

Pure and Sn-doped ZnO nanostructures were synthesized by simple chemical solution method. In this method we used zinc nitrate and NaOH as precursors. Sn doping content in ZnO was taken with the ratio 0, 5, 10, 15 and 20 percent by weight. Physical properties of Sn-doped ZnO powder were studied by XRD analysis which revealed that Sn doping had a significant effect on crystalline quality, grain size, intensity, dislocation density and strain. The calculated average grain size of pure ZnO was 21 nm. The best crystalline structure was found for 0 wt.%, 5 wt.% and 10 wt.% Sn doping as observed by FESEM and XRD. However, higher Sn-doping (> 10 wt.%) degraded the crystallinity and the grain size of 27.67 nm to 17.76 nm. The structures observed in FESEM images of the samples surfaces were irregular and non-homogeneous. EDX depicted no extra peak of impurity and confirmed good quality of the samples.

Open access

A. Hussain, M. Arshad, Z. Ahmad, H.T. Ahmad, M. Afzal and M. Ahmad

Abstract

A pot experiment in wire house was conducted to investigate the effect of potassium fertilization on physiology, growth and nutrient uptake of maize. Surface soil samples were collected and analyzed for soil physico-chemical properties and NPK contents. Pots were saturated with water and filled with soil (5 kg soil/pot). Potassium fertilizer was applied in five different treatments as T1, T2, T3, T4 and T5 with 0, 70, 100, 130, and 160 kg ha-1, respectively. Nitrogen and phosphorus were applied @ 250 and 100 kg ha-1 (recommended), respectively, in all the pots, including control. Experiment was planned in completely randomized design (CRD), with three repeats. Plant growth, nutrient uptake and concentration in roots and shoots, net photosynthesis, rate of transpiration, stomatal conductance and substomatal CO2 concentration were significantly improved with increasing K application rate. It also increased water use efficiency (WUE) and decreased root: shoot dry weight ratio of maize. Treatment T3 resulted in maximum growth, physiological characteristics and nutrient uptake. It was concluded that K fertilization improves physiological characteristics resulting in enhanced WUE and nutrient uptake eventually producing more yield. It is recommended to apply K fertilization in drought stress conditions.

Open access

M.R. Ahsan, M.T. Islam, M. Habib Ullah, H. Arshad and M.T. Ali

Abstract

In this article, a simple design of rectangular microstrip feed planar antenna with wide arcs and square shape slot is proposed for Radio Frequency Identification (RFID),Worldwide Interoperability for Microwave Access (WiMAX) and C/X-band wireless communications. The prototype of the antenna has been fabricated 1.0 mm thick ceramic filled bioplastic substrate by using optimal dimension obtained from design/simulations and antenna performances are experimentally tested. The experimental results confirm the impedance bandwidths for S11 ≤ −10 dB are of 712 MHz (0.355-1.067 GHz), 1.38 GHz (2.92-4.3 GHz) and 2.46 GHz (6.55-9.01 GHz) for 0.788, 3.34 and 8.01 GHz band respectively. The proposed antenna shows almost steady and symmetrical radiation patterns for all three bands with the maximum gains of 1.37, 2.8 and 3.56 dBi respectively. Based on the antenna performances, it can successfully cover the frequency band requirement for RFID, WiMAX and C/X-band applications.

Open access

Nadeem Siddiqui, Arpana Rana, Suroor Khan, S. Haque, M. Arshad, Sharique Ahmed and Waquar Ahsan

Synthesis and preliminary screening of benzothiazol-2-yl thiadiazole derivatives for anticonvulsant activity

Various N-(5-chloro-6-substituted-benzothiazol-2-yl)-N'-(substituted phenyl)-[1,3,4]thiadiazole-2,5-diamines (5a-t) were designed and synthesized starting from substituted acetophenones. Structures of all the compounds were confirmed on the basis of spectral and elemental analyses. All the newly synthesized compounds were screened for their anticonvulsant activity and were compared with the standard drug phenytoin sodium. Interestingly, all the compounds showed protections against seizures in the range 50-100% indicative of the promising nature of the compounds against seizure spread. Compounds 5b and 5c showed complete protection against MES induced seizures.

Open access

Kamran Saleem, Hafiz M. Imran Arshad, Sajid Shokat and Babar Manzoor Atta

Abstract

The resurgence of wheat stripe rust is of great concern for world food security. Owing to resistance breakdown and the appearance of new virulent high-temperature adapted races of Puccinia striiformis f. sp. tritici (Pst), many high yielding commercial varieties in the country lost their yield potential. Searching for new sources of resistance is the best approach to mitigate the problem. Quantitative resistance (partial or adult plant) or durable resistance is reported to be more stable than race specific resistance. In the current perusal, a repertoire of 57 promising wheat lines along with the KLcheck line Morocco, developed through hybridisation and selection of local and international lines with International Maize and Wheat Improvement Center (CIMMYT) origin, were evaluated under natural field conditions at Nuclear Institute for Agriculture and Biology (NIAB) during the 2012−2013 and 2013−2014 time periods. Final rust severity (FRS), the area under the rust progress curve (AURPC), the relative area under the rust progress curve (rAURPC), and the coefficient of infection (CI) were unraveled to infer the level of quantitative resistance. Final rust severity was recorded when the susceptible check exhibited 100% severity. There were 21 lines which were immune (no disease), 16 which were resistant, five moderately resistant, two resistant-to-moderately resistant, one moderately resistant-to-moderately susceptible, 5 moderately susceptible-to-susceptible, one moderately susceptible, and six exhibited a susceptible response. Nevertheless, 51 lines exhibited a high level of partial resistance while the three lines, NW-5-1212-1, NW-7-30-1, and NW-7-5 all showed a moderate level of partial resistance based on FRS, while 54 lines, on the basis of AURPC and rAURPC, were identified as conferring a high level of partial resistance. Moreover, adult plant resistance was conferred by 47 wheat lines, based on CI value. It was striking that, 13 immune lines among 21 were derived from parents of CIMMYT origin. Cluster analysis was executed to determine the diversity among the wheat genotypes based on stripe rust resistance and yield parameters. All genotypes were grouped into nine clusters exhibiting a high level of diversity at a 25% linkage distance. There were 29 wheat lines resistant to stripe rust that were grouped into the first three clusters, while 4 high-yielding lines were in Cluster VIII. The susceptible check, Morocco, was separated from rest of lines and fell in the last cluster i.e. Cluster IX. Based on the results, inter-crossing immune/ resistant lines is recommended, and with high yielding lines − it is also recommended that cultivars with improved disease resistance and yield potential be developed.

Open access

Ijaz Ali, Amjid Iqbal, Arshad Mahmood, A. Shah, M. Zakria and Asad Ali

Abstract

Cd1−xZnxSe (x = 0, 0.40 and 1) thin films were deposited on a glass substrate at room temperature by closed space sublimation method. Optical investigation has been performed using spectrophotometry and ellipsometry. It has been found that for as deposited films the optical band gap increased and the optical constants decreased with increasing Zn content. To improve the optical properties of Cd1−xZnxSe thin films annealing effect at 400 °C was taken into consideration for various Zn contents. It was observed that the optical transmittance and band gap decreased while optical constants increased with increasing Zn content after annealing. The effects of composition and annealing on the optical dispersion parameters Eo and Ed were investigated using a single effective oscillator model. The calculated value of the average excitation energy Eo obeys the empirical relation (Eo = Eg/2) obtained from the single oscillator model.

Open access

M. Zakria, Taj Muhammad Khan, Abbas Nasir and Arshad Mahmood

Abstract

Cd1−xZnxS thin films of variable compositions (x = 0.2, 0.4, 0.6, 0.8) were deposited on glass at room temperature by thermal evaporation process. The prepared samples were annealed at two different temperatures (300 °C, 400 °C) for 1 hour in ambient air. The effects of post-annealing on the structural and optical characteristics were investigated using X-ray diffraction (XRD), spectrophotometry, and Raman spectroscopy (RS) methods. XRD studies suggested that the annealed and as-deposited samples belong to wurtzite structure for all Zn concentrations with a preferential orientation along (002) plane. Spectrophotometry analysis of the samples revealed that the energy band gap decreased with annealing temperature. RS investigated different phonon bands and crystalline phases. Two longitudinal optical phonon modes (1-LO, 2-LO) corresponding to monophase hexagonal structure were observed for all Cd1−xZnxS samples. The observed red-shift and anti-symmetrical nature of the 1-LO phonon mode can be associated with annealing, while the overall blue-shift, except for x ⩽ 0.6, was caused by the structural disorders in periodic Cd atomic sub-lattices and broken translational symmetry. The spectroscopic results were strengthened by the XRD studies and their results are consistent.

Open access

Nisar Ahmed, Azeem Nabi, Jawad Nisar, Muhammad Tariq, Muhammad Arshad Javid and M. H. Nasim

Abstract

The electronic structure and magnetic properties of Mn doped zinc blende cadmium sulfide Cd1-xMnxS (x = 6.25 %) have been studied using spin-polarized density functional theory within the framework of Generalized Gradient Approximation (GGA), its further corrections including Hubbard U interactions (GGA + U) and a model for exchange and correlation potential Tran Blaha modified Becke-Johnson (TB-mBJ). Ferromagnetic interactions have been observed between Mn atoms via S atom due to strong p-d hybridization. The magnetic moments on Mn and its neighboring atoms have also been studied in detail using different charge analysis techniques. It has been observed that p-d hybridization reduced the value of local magnetic moment of Mn in comparison to its free space charge value and produced small local magnetic moments on the nonmagnetic S and Cd host sites. The magnetocrystalline anisotropy in [1 0 0] and [1 1 1] directions as well as exchange splitting parameters Noα and Noβ have been analyzed to confirm that ferromagnetism exists. We conclude that the ferromagnetic phase in Mn-doped CdS is not stable in “near” configuration but it is stable for “far” configuration. Mn doped CdS is a p-type semiconductor and the d-states at the top of the valence band edge give a very useful material for photoluminescence and magneto-optical devices.

Open access

S.M. Kahar, C.H. Voon, C.C. Lee, U. Hashim, M.K. Md Arshad, B.Y. Lim, S.C.B. Gopinath and W. Rahman

Abstract

Silicon carbide (SiC) is an important ceramics for engineering and industrial applications due to its advantage to withstand in high temperatures. In this article, a demonstration of SiC nanowhiskers synthesis by using microwave heating has been shown. The mixtures of raw materials in the form of pellets were heated, using a laboratory microwave furnace, to 1400 °C for 40 minutes at a heating rate of 20 °C/min. The characterization process proved that the mixture of graphite and silica in the ratio of 1:3 is an ideal composition for synthesizing single phase β-SiC nanowhiskers. Vapor-solid mechanism was suggested to explain the formation of SiC nanowhiskers by the proposed microwave heating.

Open access

Mahmood Ahmed, Muhammad Abdul Qadir, Muhammad Imtiaz Shafiq, Muhammad Muddassar, Abdul Hameed, Muhammad Nadeem Arshad and Abdullah M. Asiri

Abstract

Curcumin is a natural product with enormous biological potential. In this study, curcumin synthesis was revisited using different reaction solvents, a catalyst (n-butylamine) and a water scavenger [(n-BuO)3B], to develop the optimal procedure for its rapid acquisition. During synthesis, solvent choice was found to be an important parameter for better curcumin yield and high purity. In a typical reaction, acetyl acetone was treated with boron trioxide, followed by condensation with vanillin in the presence of tri-n-butyl borate as water scavenger and n-butylamine as catalyst at 80 °C in ethyl acetate to afford curcumin. Moreover, curcumin was also extracted from turmeric powder and spectroscopic properties such as IR, MS, 1H NMR and 13C NMR with synthetic curcumin were established to identify any impurity. The purity of synthetic and extracted curcumin was also checked by TLC and HPLC-DAD. To computationally assess its therapeutic potential against cyclin dependent kinases (CDKs), curcumin was docked in different isoforms of CDKs. It was observed that it did not dock at the active sites of CDK2 and CDK6. However, it could enter into weak interactions with CDK4 protein.