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51.
Fazal-ur Rehman Shahid Adeel Summia Qaiser Ijaz Ahmad Bhatti Muhammad Shahid Mohammad Zuber 《Radiation Physics and Chemistry》2012,81(11):1752-1756
Dyeing behavior of gamma irradiated cotton fabric using Lawson dye extracted from henna leaves has been investigated. Cotton and dye powder are irradiated to different absorbed doses of 2, 4, 6, 8 and 10 kGy using Cs-137 gamma irradiator. The dyeing parameters such as dyeing time, electrolyte (salt) concentration and mordant concentrations using copper and iron as mordants are optimized. Dyeing is performed using un-irradiated and irradiated cotton with dye solutions and their color strength values are evaluated in CIE Lab system using Spectraflash –SF650. Methods suggested by International Standard Organization (ISO) have been employed to investigate the colourfastness properties such as colourfastness to light, washing and rubbing of irradiated dyed fabric. It is found that gamma ray treatment of cotton dyed with extracts of henna leaves has significantly improved the color strength as well as enhanced the rating of fastness properties. 相似文献
52.
Previously unknown boron-containing four-membered unsaturated heterocycle boretane was obtained via novel thermal rearrangement of cyclopropylborane and investigated by NMR and IR spectroscopy. Formation of boretane was also confirmed through its chemical transformation into more stable derivatives. 相似文献
53.
54.
Anderson AW Heptulla RA Driesen N Flanagan D Goldberg PA Jones TW Rife F Sarofin H Tamborlane W Sherwin R Gore JC 《Magnetic resonance imaging》2006,24(6):693-697
Functional magnetic resonance imaging (fMRI) was used to measure the effects of acute hypoglycemia caused by passive sensory stimulation on brain activation. Visual stimulation was used to generate blood-oxygen-level-dependent (BOLD) contrast, which was monitored during hyperinsulinemic hypoglycemic and euglycemic clamp studies. Hypoglycemia (50 +/- 1 mg glucose/dl) decreased the fMRI signal relative to euglycemia in 10 healthy human subjects: the fractional signal change was reduced by 28 +/- 12% (P < .05). These changes were reversed when euglycemia was restored. These data provide a basis of comparison for studies that quantify hypoglycemia-related changes in fMRI activity during cognitive tasks based on visual stimuli and demonstrate that variations in blood glucose levels may modulate BOLD signals in the healthy brain. 相似文献
55.
Sumera Zaib Rubina Munir Muhammad Tayyab Younas Naghmana Kausar Aliya Ibrar Sehar Aqsa Noorma Shahid Tahira Tasneem Asif Hashem O. Alsaab Imtiaz Khan 《Molecules (Basel, Switzerland)》2021,26(21)
Alzheimer’s disease (AD) is a progressive neurodegenerative disorder and the leading cause of dementia worldwide. The limited pharmacological approaches based on cholinesterase inhibitors only provide symptomatic relief to AD patients. Moreover, the adverse side effects such as nausea, vomiting, loss of appetite, muscle cramps, and headaches associated with these drugs and numerous clinical trial failures present substantial limitations on the use of medications and call for a detailed insight of disease heterogeneity and development of preventive and multifactorial therapeutic strategies on urgent basis. In this context, we herein report a series of quinoline-thiosemicarbazone hybrid therapeutics as selective and potent inhibitors of cholinesterases. A facile multistep synthetic approach was utilized to generate target structures bearing multiple sites for chemical modifications and establishing drug-receptor interactions. The structures of all the synthesized compounds were fully established using readily available spectroscopic techniques (FTIR, 1H- and 13C-NMR). In vitro inhibitory results revealed compound 5b as a promising and lead inhibitor with an IC50 value of 0.12 ± 0.02 μM, a 5-fold higher potency than standard drug (galantamine; IC50 = 0.62 ± 0.01 μM). The synergistic effect of electron-rich (methoxy) group and ethylmorpholine moiety in quinoline-thiosemicarbazone conjugates contributes significantly in improving the inhibition level. Molecular docking analysis revealed various vital interactions of potent compounds with amino acid residues and reinforced the in vitro results. Kinetics experiments revealed the competitive mode of inhibition while ADME properties favored the translation of identified inhibitors into safe and promising drug candidates for pre-clinical testing. Collectively, inhibitory activity data and results from key physicochemical properties merit further research to ensure the design and development of safe and high-quality drug candidates for Alzheimer’s disease. 相似文献
56.
Important parameters of hydroxybutyl 4-aroyloxybenzoate ligands were calculated and correlations were made between theoretical and experimental results. In addition, supramolecular side-chain liquid crystalline polymers of the ligands with poly(4-vinylpyridine) were synthesized. Hydrogen bond formation was ascertained by Fourier tranform infra-red spectroscopy. The stabilities of the complexes were determined by thermogravimetric analysis. The mesomorphic behavior was investigated using differential scanning calorimetry, polarizing optical microscopy and X-ray diffraction analysis. Semiempirical study revealed that a ratio of ~1.2 in the lengths of flexible and rigid parts of the molecules is the most favorable for a wider liquid crystal (LC) temperature range. 相似文献
57.
K. Rubina E. Abele S. Belyakov I. Shestakova Yu. Popelis 《Russian Journal of Organic Chemistry》2006,42(5):735-738
A two-stage method was developed for the conversion of phenyl-and pyridylaldoximes and ketoximes into the corresponding O-[3-(5-tetrazolyl)propyl]oximes. The structure of the sodium salt of 2-acetylpyridine O-[3-(5-tetrazolyl)propyl]oxime was established X-ray diffraction analysis. This compound was shown to possess a high cytotoxic activity in vitro. 相似文献
58.
M. A. Mikhaleva G. A. Kolesnichenko K. I. Rubina Yu. Sh. Gol'dberg V. A. Savel'ev L. Ya. Leitis M. V. Shimanskaya V. P. Mamaev 《Chemistry of Heterocyclic Compounds》1986,22(3):310-318
5-Arylpyrimidine-2-carboxylic acids were synthesized by the hydrolysis of 5-aryl-2-cyanopyrimidines and the oxidation of 5-aryl-2-styrylpyrimidines under the conditions of phase-transfer catalysis. The aryl esters of the acids were obtained, and their liquid-crystal characteristics were studied. The p-substituted aryl esters of 5-phenylpyrimidine-2-carboxylic acid do not exhibit mesomorphism, but the introduction of a butyloxy group at the p position of the phenyl residue leads to the appearance of nematic characteristics. Aryl 5-phenylpyrimidinylcarbonyloxy-benzoates are nematic liquid crystals with a thermally stable meso phase and an existence range of 50–80 °C.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 380–388 March, 1986.The authors express their gratitude to M. F. Grebenkin and V. T. Lazareva for useful discussion of the results. 相似文献
59.
Dudnik AS Sromek AW Rubina M Kim JT Kel'in AV Gevorgyan V 《Journal of the American Chemical Society》2008,130(4):1440-1452
A general, mild, and efficient 1,2-migration/cycloisomerization methodology toward multisubstituted 3-thio-, seleno-, halo-, aryl-, and alkyl-furans and pyrroles, as well as fused heterocycles, valuable building blocks for synthetic chemistry, has been developed. Moreover, regiodivergent conditions have been identified for C-4 bromo- and thio-substituted allenones and alkynones for the assembly of regioisomeric 2-hetero substituted furans selectively. It was demonstrated that, depending on reaction conditions, ambident substrates can be selectively transformed into furan products, as well as undergo selective 6-exo-dig or Nazarov cyclizations. Our mechanistic investigations have revealed that the transformation proceeds via allenylcarbonyl or allenylimine intermediates followed by 1,2-group migration to the allenyl sp carbon during cycloisomerization. It was found that 1,2-migration of chalcogens and halogens predominantly proceeds via formation of irenium intermediates. Analogous intermediate can also be proposed for 1,2-aryl shift. Furthermore, it was shown that the cycloisomerization cascade can be catalyzed by Br?nsted acids, albeit less efficiently, and commonly observed reactivity of Lewis acid catalysts cannot be attributed to the eventual formation of proton. Undoubtedly, thermally induced or Lewis acid-catalyzed transformations proceed via intramolecular Michael addition or activation of the enone moiety pathways, whereas certain carbophilic metals trigger carbenoid/oxonium type pathway. However, a facile cycloisomerization in the presence of cationic complexes, as well as observed migratory aptitude in the cycloisomerization of unsymmetrically disubstituted aryl- and alkylallenes, strongly supports electrophilic nature for this transformation. Full mechanistic details, as well as the scope of this transformation, are discussed. 相似文献
60.
Rizi Ai M. Qaiser Fatmi Chia-en A. Chang 《Journal of computer-aided molecular design》2010,24(10):819-827
T-Analyst is a user-friendly computer program for analyzing trajectories from molecular modeling. Instead of using Cartesian
coordinates for protein conformational analysis, T-Analyst is based on internal bond-angle-torsion coordinates in which internal
torsion angle movements, such as side-chain rotations, can be easily detected. The program computes entropy and automatically
detects and corrects angle periodicity to produce accurate rotameric states of dihedrals. It also clusters multiple conformations
and detects dihedral rotations that contribute hinge-like motions. Correlated motions between selected dihedrals can also
be observed from the correlation map. T-Analyst focuses on showing changes in protein flexibility between different states
and selecting representative protein conformations for molecular docking studies. The program is provided with instructions
and full source code in Perl. 相似文献