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51.
Wheat seeds were grown in the presence and absence of some trace elements like Co, Cu, Fe, Mn, Mo and Zn in non-toxic limits. The level of enzyme activities involved in nucleic acid metabolism were measured by spectrophotometric methods. The level of certain RNA metabolising enzymes increased manyfold in trace element-treated seeds, while the level of AMP-deaminase was increased manyfold in Co-treated seeds. 相似文献
52.
Shaista Zeb A. Qayyum Mehboob Sadiq M. Shafiq A. Waheed M. Zakaullah 《Plasma Chemistry and Plasma Processing》2007,27(2):127-139
This paper reports the deposition of diamond-like carbon (DLC) films on Si <100>, using a low energy (1.45 kJ) dense plasma
focus assisted sputtering of graphite insert at the tip of the tapered anode. The substrates are placed in front of the anode
at different axial and angular positions and are exposed to multiple focus shots. The information regarding the DLC structure
is acquired by using Raman spectroscopy. The spectra are characterized by two broad bands known as “G-band” and “D-band”.
The results point towards the formation of DLC films with both sp3 (diamond like) and sp2 (graphite like) domains. In X-ray diffraction (XRD) pattern, no additional peak is observed except a peak at 2θ = 69° which corresponds to the silicon (Si) substrate. The intensity of Si peak is reduced after treatment indicating the
deposition of amorphous carbon. Scanning electron microscopy (SEM) results demonstrate that the smoothness of the film increases
with increasing the substrate angular positions with respect to the anode axis. Energy dispersive X-ray (EDX) analysis reveals
that the films deposited at lower axial and angular positions are thicker which is complemented by the cross-sectional views
of the films. 相似文献
53.
Farhat Ullah Abdul Sadiq Abid Hussain Sajjad Ahmad Muhammad Imran 《Natural product research》2016,30(12):1440-1444
This study was designed to investigate antioxidant and anticholinesterase potential of Iris germanica var; florentina. Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory potential of plant samples were investigated by Ellman’s assay. Antioxidant activity was performed using DPPH, H2O2 and ABTS free radical scavenging assays. Total phenolics and flavonoids contents were expressed in mg GAE/g dry weight and mg RTE/g, respectively. In AChE inhibition assay, Ig.Fl, Ig.Sp and Ig.Cf fractions exhibited highest activity with IC50 values of < 0.1, 5.64 and 19 μg/mL, respectively. In BChE inhibitory assay, Ig.Fl, Ig.Sp, Ig.Cf and Ig.Cr were most active with IC50 of < 0.1, < 0.1, 31 and 78 μg/mL, respectively. In DPPH assay, Ig.Fl and Ig.Cf exhibited highest inhibition of free radicals, 80.52% (IC50 = 9 μg/mL) and 78.30% (IC50 = 8 μg/mL), respectively. In ABTS assay Ig.Cr, Ig.Cf, Ig.Fl and Ig.Sp exhibited IC50 values of < 0.1, 2, 2 and 3 μg/mL, respectively. 相似文献
54.
Barnes NA Brisdon AK Brown FR Cross WI Herbert CJ Pritchard RG Sadiq G 《Dalton transactions (Cambridge, England : 2003)》2008,(1):101-114
The coordination chemistry of the perfluorovinyl phosphines PEt2(CF=CF2), P(i)Pr2(CF=CF2), PCy,(CF=CF2) and PPh(CF=CF2)2 to rhodium(I), palladium(II), and platinum(II) centres has been investigated. The electronic properties of the ligands are estimated based on v(CO) and 1J(Rh-P) values. X-Ray diffraction data for the square-planar Pd(II) and Pt(II) perfluorovinyl-phosphine containing complexes allow estimates of the steric demand for the series of ligands PPh2(CF=CF2), PEt2(CF=CF2), P(i)Pr2(CF=CF2), PCy2(CF=CF2) and PPh(CF=CF2)2 to be determined. The (CF=CF2) fragment is found to be more electron withdrawing than (C6F5) yet sterically less demanding. These ligands therefore provide a range of electron-neutral to phosphite-like electronic properties combined with a range of steric demands. This study also reveals that short intramolecular interactions from the metal centre to the beta-fluorine atom cis to phosphorus of the CF=CF2 groups are observed in all-trans square planar complexes of the ligands. Unusually, the complex [PtCl2{P(i)Pr2(CF=CF2)}2] crystallises with both cis- and trans-isomers present in the unit cell. It appears that co-crystallisation of both isomers occurs in order to maximise fluorous regions in the crystal packing, and the extended structure displays short fluorine-fluorine contacts. The generation of mixed geometries seems to be a phenomenon of crystallisation, as solution phase NMR studies reveal the presence of only the trans-isomer. 相似文献
55.
Golam Kabir Solomon Tesfamariam Alex Francisque Rehan Sadiq 《European Journal of Operational Research》2015
It has been reported that since year 2000, there have been an average 700 water main breaks per day only in Canada and the USA costing more than CAD 10 billions/year. Moreover, water main leaks affect other neighboring infrastructure that may lead to catastrophic failures. For this, municipality authorities or stakeholders are more concerned about preventive actions rather reacting to failure events. This paper presents a Bayesian Belief Network (BBN) model to evaluate the risk of failure of metallic water mains using structural integrity, hydraulic capacity, water quality, and consequence factors. BBN is a probabilistic graphical model that represents a set of variables and their probabilistic relationships, which also captures historical information about these dependencies. The proposed model is capable of ranking water mains within distribution network that can identify vulnerable and sensitive pipes to justify proper decision action for maintenance/rehabilitation/replacement (M/R/R). To demonstrate the application of proposed model, water distribution network of City of Kelowna has been studied. Result indicates that almost 9% of the total 259 metallic pipes are at high risk in both summer and winter. 相似文献
56.
57.
Nugent TC Sadiq A Bibi A Heine T Zeonjuk LL Vankova N Bassil BS 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(13):4088-4098
Relying on the assembly of commercially available catalyst building blocks, highly stereocontrolled quaternary carbon (all carbon substituted) formation has been achieved with unmatched substrate diversity. For example, the in situ assembly of a tricomponent catalyst system allows α-branched aldehyde addition to nitroalkene or maleimide electrophiles (Michael products), while addition to an α-iminoester affords Mannich reaction products. Very good yields are observed and for fifteen of the eighteen examples 96-99?% ee is observed. Using racemic α-branched aldehydes, two contiguous (quaternary-tertiary) stereogenic centers can be formed in high diastereo- and enantiomeric excess (eight examples) via an efficient in situ dynamic kinetic resolution, solving a known shortcoming for maleimide electrophiles in particular. The method is of practical value, requiring only 1.2?equiv of the aldehyde, a 5.0?mol?% loading of each catalyst component, for example, O-tBu-L-threonine (O-tBu-L-Thr), sulfamide, DMAP or O-tBu-L-Thr, KOH, and room temperature reactions. As a highlight, the first demonstration of ethylisovaleraldehyde (7) addition is disclosed, providing the most congested quaternary stereogenic carbon containing succinimide product (8) known to date. Finally, mechanistic insight, via DFT calculations, support a noncovalent assembly of the catalyst components into a bifunctional catalyst, correctly predict two levels of product stereoselectivity, and suggest the origin of the tricomponent catalyst system's exceptionality: an alternative hydrogen bond motif for the donor-acceptor pair than currently suggested for non-assembled catalysts. 相似文献
58.
This paper explores the application of ordered weighted averaging (OWA) operators to develop water quality index, which incorporates an attitudinal dimension in the aggregation process. The major thrust behind selecting the OWA operator for aggregation of multi-criteria is its capability to encompass a range of operators bounded between minimum and maximum. A new approach for generating OWA weight distributions using probability density functions (PDFs) is proposed in this paper. The basic parameters (mean and standard deviation) of the probability density functions can be determined using the number of criteria (e.g., water quality indicators) in the aggregation process. 相似文献
59.
Muhammad Kaleem Khosa Masood Parvez Muhammad Mazhar Saqib Ali Sadiq‐ur‐Rehman 《应用有机金属化学》2005,19(1):202-202
The germanium atom in [(C6H5)3GeCH(4‐ClC6H4)CH2C(C6H5)2OH] is in a distorted tetrahedral geometry. Steric hindrance precludes O? H···O intra‐ or inter‐molecular bonding. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
60.
Nazish Khan Akhtar Nadhman Sadiq Azam Inam Ullah Farhan Ahmad 《Green Chemistry Letters and Reviews》2020,13(2):69-82
ABSTRACT The current study aims to assess the aqueous extract of Pinus wallichiana stem for the synthesis of small spherical-shaped (10–30?nm) silver nanoparticles (AgNPs) and their in-vitro and in-vivo biomedical applications. The biosynthesized AgNPs were nonmutagenic and safe at all test doses as per Ames and acute toxicity assay (20, 40, 60, and 80?mg/kg). The percent writhing inhibitory effect generated by AgNPs was 42.51, 50.84, and 59.06 at test doses of 10, 20, and 30?mg/kg, respectively. The percent decreased in gastrointestinal tract motility observed was 41.34%, 32.69%, and 28.48% at 10, 20, and 30?mg/kg, respectively. They also showed a significant antipyretic effect after 1, 2, and 3?h in comparison to normal saline. The AgNPs of P. wallichiana showed good antibacterial activity against Acinetobacter baumannii (60% with MIC50?=?2.36?mg/ml and MBC?=?5.0?mg/ml). These nanoparticles also possessed good antioxidant activity of 61.77?±?0.828% and 70.25?±?0.56% at 400 and 500?µg/ml, respectively and lack phytoagglutinin potential. Because of their high potency as biomedical agents, these nanoparticles can be a good alternative to the currently available drugs and approaches. 相似文献