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131.
Perveen R Jamil Y Ashraf M Ali Q Iqbal M Ahmad MR 《Photochemistry and photobiology》2011,87(6):1453-1463
The water-soaked seeds of sunflower were exposed to low power continuous wave He-Ne laser irradiation of energies 0, 100, 300 and 500 mJ to evaluate the effect on various biochemical, physiological, growth and yield parameters of sunflower. The experiments which consisted of four replicates arranged in a completely randomized design (CRD) were carried out under the greenhouse conditions. The physiological attributes like, photosynthetic rate (A), transpiration rate (E), intrinsic CO(2) concentration (C(i) ), stomatal conductance (g(s)), chlorophyll a and b contents, relative membrane permeability and leaf water (ψ(w)), osmotic (ψ(s)) and turgor (ψ(p)) potentials, relative water contents and leaf area increased significantly as compared to control due to He-Ne treatment of seeds. The activities of superoxide dismutase, peroxidase and catalases and contents of total soluble proteins, malondialdehyde, proline and leaf total phenolic also increased due to laser treatment. Significant increase in growth parameters of sunflower like shoot fresh and dry masses, root fresh and dry masses, root and shoot lengths, number of leaves per plant and stem diameter has also been observed. The contents of K, Ca and Mg in shoot and root were also increased and an overall increase of up to 28.12% was observed due to laser treatment. 相似文献
132.
Iqbal M Black RJ Winn J Reeder AT Blake AJ Clarke PA 《Organic & biomolecular chemistry》2011,9(14):5062-5078
A series of diverse natural product-like structures have been synthesised by the use of a number of novel transannulation reactions across a cyclononene ring. Transannular cyclisations through oxygen functionality have generated a number of bicyclo[5.3.1]systems containing bridged cyclic ethers and bicyclo[5.2.2]lactones, as well as a tetrahydrofuran-containing bridged analogue of hexacyclinic acid. An unprecedented Br?nsted acid mediated transannular cyclisation between proximal carbons generated bicyclo[4.3.0]nonanes which form the core of the pinguisane and austrodorane families of sesquiterpenoids. In all cases the key factor that determined the mode of reactivity was the conformation of the nine-membered ring and the distance between the reacting centres. 相似文献
133.
El Sayed H. El Ashry Atta-ur-Rahman M. Iqbal Choudhary Sherif H. Kandil Ahmed El Nemr Tahsin Gulzar Aida H. Shobier 《Chemistry of Natural Compounds》2011,47(3):335-338
Phytochemical investigations on a marine green alga Ulva lactuca led to the isolation of two new compounds (E)-6-heptacosen-5-one (1) and (E)-6-octadecen-5-ol (2), along with four known compounds, (Z)-10-hexacosene (3), docosanoic acid (4), palmitic acid (5), and isofucosterol (6). Compounds 3 and 4 were isolated for the first time from this species. The structures of the compounds were deduced with the help of modern
spectroscopic techniques. 相似文献
134.
Fatima Bi Seema Iqbal Muhammad Arman Amanat Ali Mahmood-ul Hassan 《Journal of Saudi Chemical Society》2011,15(3):269-273
The effects of polysaccharide elicitor k-carrageenan obtained from Hypnea musciformis, red algae on the production of Induced Secondary Metabolites, ISMs (the disease resistance compounds) and on various growth characters of chickpea and maize plants were studied. Experiments were conducted in the field of PCSIR Laboratories Complex Karachi during December 2008–April 2009 in randomized complete block design with three replications. Three elicitor treatments were used, a solid preparation in which the elicitor was mixed with soil (T2 1 mg/g) and applied around the seeds in the soil. The two other preparations were liquid, T1 and T3 at a concentration of 100 μg glc eq ml−1 and were applied around the sowing seeds and as a foliar spray on the plants, respectively. Statistical analysis of the data revealed that these treatments significantly enhanced all the growth characters of chickpea except T2 that gave the nonsignificant difference in the plant height. Maximum plant height (80.3 cm), number of pods plant−1 (76.2), number of branches plant−1 (25.0), number of leaves plant−1 (125.6), earlier flowering and high ISMs contents in leaves, stem and grains of chickpea were recorded in T1 treated chickpea plants. In maize plants only T1 and T3 treatments (with minor exceptions) had significant effects on few characters like plant height, stem diameter, number of leaves plant−1 and on ISMs contents in leaves while number of cobs plant−1 and flowering time were nonsignificantly affected by these treatments. These results suggested that k-carrageenan elicitor can be used as a potent plant protectant as well as growth promoting agent especially for chickpea plants. 相似文献
135.
Akhtar J Mehmood RF Malik MA Iqbal N O'Brien P Raftery J 《Chemical communications (Cambridge, England)》2011,47(6):1899-1901
We describe for the first time the use of a single source precursor to deposit thin films and nanocrystals of palladium selenide. 相似文献
136.
Javed Iqbal Feroza Hamid Wattoo Muhammad Hamid Sarwar Wattoo Rukhsana Malik Syed Ahmad Tirmizi Muhammad Imran Allah Bux Ghangro 《Arabian Journal of Chemistry》2011,4(4):389-395
Chitosan flakes, extracted from prawns and labeo rohita scales, with high adsorption capacity were prepared after chemical treatment and were used to remove acid yellow dye from water. The results showed that adsorption capacity is dependent on pH, initial concentration of dye, BET, Langmuir surface area and pore volume of the adsorbent. In acidic conditions, the polymer amino groups were protonated (positively charged polymer chain), which showed attraction with negative ions of anionic dye. Chitosan from prawns scales showed higher dye adsorption under the same experimental conditions. Adsorption isotherms were developed and equilibrium data fitted well to Langmuir and Freundlich isotherm models. 相似文献
137.
Shahid Hussain Arshad Muhammad Nawaz Naeem Nazra Sultana Zafar Iqbal Abdul Ghafar Shah 《Archive of Applied Mechanics (Ingenieur Archiv)》2011,81(8):999-1016
In the present work, vibration characteristics of thin functionally graded cylindrical shells are studied under the influence
of various boundary conditions. Fabrication of FGM cylindrical shell is carried out by using exponential volume fraction law.
Strain- and curvature-displacements relationships are taken from Love’s thin shell theory. The frequency equation in the form
of eigenvalue problem is obtained by adapting the Rayleigh-Ritz method. Characteristic beam functions are assumed to approximate
the axial modal dependence. Effects of exponential volume fraction law on the natural frequencies of the FGM cylindrical shells
for various boundary conditions are studied against circumferential wave number, length to radius ratio and thickness to radius
ratio for different values of power law exponents. Results evaluated show good agreement with those available in the literature. 相似文献
138.
Thin films of SnSb2S4 have been prepared on glass substrate by using thermal evaporation techniques. The films were annealed in argon gas at low pressure in sealed glass ampoules at 85 °C, 150 °C, 275 °C and 325 °C. XRD of the films reveal that the low temperature annealed films are poly crystalline while the as deposited films and high annealed films are in amorphous states. There is no adequate variation in the photoconductivity response of the amorphous and crystalline phases. The transmittance of the films is low and having no transmittance below 740 nm. The band gap calculated by ellipsometry technique is in the range of 1.82–3.1 eV. The films have n-type conductivity but the film annealed at 325 °C show p-type conductivity. 相似文献
139.
Muhammad Zaman Muhammad Hammad Butt Waqar Siddique Muhammad Omer Iqbal Naveed Nisar Asma Mumtaz Hafiza Yusra Nazeer Abdulrahman Alshammari Muhammad Shahid Riaz 《Molecules (Basel, Switzerland)》2022,27(23)
Tenofovir alafenamide (TAF) is an antiretroviral (ARV) drug that is used for the management and prevention of human immunodeficiency virus (HIV). The clinical availability of ARV delivery systems that provide long-lasting protection against HIV transmission is lacking. There is a dire need to formulate nanocarrier systems that can help in revolutionizing the way to fight against HIV/AIDS. Here, we aimed to synthesize a polymer using chitosan and polyethylene glycol (PEG) by the PEGylation of chitosan at the hydroxyl group. After successful modification and confirmation by FTIR, XRD, and SEM, TAF-loaded PEGylated chitosan nanoparticles were prepared and analyzed for their particle size, zeta potential, morphology, crystallinity, chemical interactions, entrapment efficacy, drug loading, in vitro drug release, and release kinetic modeling. The fabricated nanoparticles were found to be in a nanosized range (219.6 nm), with ~90% entrapment efficacy, ~14% drug loading, and a spherical uniform distribution. The FTIR analysis confirmed the successful synthesis of PEGylated chitosan and nanoparticles. The in vitro analysis showed ~60% of the drug was released from the PEGylated polymeric reservoir system within 48 h at pH 7.4. The drug release kinetics were depicted by the Korsmeyer–Peppas release model with thermodynamically nonspontaneous drug release. Conclusively, PEGylated chitosan has the potential to deliver TAF from a nanocarrier system, and in the future, cytotoxicity and in vivo studies can be performed to further authenticate the synthesized polymer. 相似文献
140.
Sarosh Iqbal Nimra Naveed Shaikh Khalid Mohammed Khan Shumaila Kiran Sehrish Naz Zaheer Ul-Haq Shahnaz Perveen M. Iqbal Choudhary 《Molecules (Basel, Switzerland)》2022,27(22)
Currently the discovery and development of potent β-glucuronidase inhibitors is an active area of research due to the observation that increased activity of this enzyme is associated with many pathological conditions, such as colon cancer, renal diseases, and infections of the urinary tract. In this study, twenty-seven 2-aminopyrimidine derivatives 1–27 were synthesized by fusion of 2-amino-4,6-dichloropyrimidine with a variety of amines in the presence of triethylamine without using any solvent and catalyst, in good to excellent yields. All synthesized compounds were characterized by EI-MS, HREI-MS and NMR spectroscopy. Compounds 1–27 were then evaluated for their β-glucuronidase inhibitory activity, and among them, compound 24 (IC50 = 2.8 ± 0.10 µM) showed an activity much superior to standard D-saccharic acid 1,4-lactone (IC50 = 45.75 ± 2.16 µM). To predict the binding mode of the substrate and β-glucuronidase, in silico study was performed. Conclusively, this study has identified a potent β-glucuronidase inhibitor that deserves to be further studied for the development of pharmaceutical products. 相似文献