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371.
Rasheed Tabish Siddiqui Shamoon Ahmad Kargeti Ankit Shukla Dharmesh Vikram Singh Vijay Pandey Anoop Kumar 《Structural chemistry》2021,32(6):2209-2221
Structural Chemistry - Unique superhalogen properties of Pt(CN)n complexes (n = 1–6) have been investigated under the quantum chemical formalism. The study involves theoretical calculations... 相似文献
372.
Naveen Mukhtar Abdul Malik Naheed Riaz Kiran Iqbal RasoolBakhsh Tareen ShamsunNahar Khan SarfrazAhmad Nawaz Juveria Siddiqui M.Iqbal Choudhary 《Helvetica chimica acta》2004,87(2):416-424
Pakistolides A and B, novel dimeric β‐(glucosyloxy)benzoates were isolated from Berchemia pakistanica and assigned structures 1 and 2 on the basis of extensive NMR studies. In addition, the known compounds 7,5′‐dimethoxy‐3,5,2′‐trihydroxyflavone (=3,5‐dihydroxy‐2‐(2‐hydroxy‐5‐methoxyphenyl)‐7‐methoxy‐4H‐1‐benzopyran‐4‐one), 4′,5‐dihydroxy‐3,6,7‐trimethoxyflavone (=5‐hydroxy‐2‐(4‐hydroxyphenyl)‐3,6,7‐trimethoxy‐4H‐1‐benzopyran‐4‐one), 5,6‐dihydroxy‐4,7‐dimethoxy‐2‐methylanthracene‐9,10‐dione, and 1,3,4‐trihydroxy‐6,7,8‐trimethoxy‐2‐methylanthracene‐9,10‐dione were reported for the first time from the genus Berchemia. Both 1 and 2 showed significant α‐glucosidase and lipoxygenase inhibitory activities, while 2 also showed antioxidant potential. 相似文献
373.
A. P. Quayle A. S. Siddiqui S. J.M. Jones 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,50(4):617-630
We propose a model of an underlying mechanism responsible for the formation of assortative mixing in networks between “similar”
nodes or vertices based on generic vertex properties. Existing models focus on a particular type of assortative mixing, such
as mixing by vertex degree, or present methods of generating a network with certain properties, rather than modeling a mechanism
driving assortative mixing during network growth. The motivation is to model assortative mixing by non-topological vertex
properties, and the influence of these non-topological properties on network topology. The model is studied in detail for
discrete and hierarchical vertex properties, and we use simulations to study the topology of resulting networks. We show that
assortative mixing by generic properties directly drives the formation of community structure beyond a threshold assortativity
of r ∼0.5, which in turn influences other topological properties. This direct relationship is demonstrated by introducing
a new measure to characterise the correlation between assortative mixing and community structure in a network. Additionally,
we introduce a novel type of assortative mixing in systems with hierarchical vertex properties, from which a hierarchical
community structure is found to result.
Electronic supplementary material Supplementary Online Material 相似文献
374.
M. A. Loureno M. S. A. Siddiqui R. M. Gwilliam G. Shao K. P. Homewood 《Physica E: Low-dimensional Systems and Nanostructures》2003,16(3-4):376
Efficient silicon-based light emitting diodes have been fabricated using the dislocation engineering method. Crucially this technique uses entirely conventional ULSI processes. The devices were fabricated by conventional low-energy boron implantation into silicon substrates followed by high-temperature annealing, and strong silicon band edge luminescence was observed. Dislocation engineering is also shown to reduce the thermal quenching for other material systems. Dislocation engineered β-FeSi2 and Er light emitting devices were fabricated and room temperature electroluminescence at 1.5 μm was observed in both cases. 相似文献
375.
Abdur Rauf Ghias Uddin Haroon Khan Mohammad Arfan Bina S. Siddiqui 《Natural product research》2016,30(4):426-428
The aim of this study was to explore the extract/fractions and compounds of Diospyros lotus against various Gram-positive and Gram-negative bacteria strain. The results showed marked susceptibility of extract and its fractions against test pathogens. Among them, chloroform fraction was most dominant and effective against all tested bacteria. The chloroform fraction was subjected to column chromatography which led to the isolation of lupeol (1), 7-methyljuglone (2), β-sitosterol (3), stigmasterol (4), betulinic acid (5), diospyrin (6) and 8-hydroxyisodiospyrin (7). Among the isolated compounds, betulinic acid (5) showed significant activity against most of the tested pathogen. In conclusion, our study validated the traditional uses of the plant in the treatment of infectious diseases which was also strongly supported by the isolated compound, betulinic acid (5). 相似文献
376.
Rasheed K Tariq MI Munir C Hussain I Siddiqui HL 《Chemical & pharmaceutical bulletin》2008,56(2):168-172
A series of group 12 elements for Zn(II), Cd(II), Hg(II) complexes of glibenclamide were synthesized and characterized using various spectroscopic techniques and magnetic moments. The complexes exhibited significant activity against gram-negative and gram-positive bacteria species. Zn(II) complex showed remarkable hypoglycemic activity whereas Cd(II) and Hg(II) complexes exhibited antibacterial activity. 相似文献
377.
Two new pentacyclic triterpenoids, namely lantanoic acid (1) and camaranoic acid (2), and six known compounds such as lantic acid, camarinic acid, camangeloyl acid, camarinin, oleanonic acid, and ursonic acid were isolated from the aerial parts of Lantana camara LINN. Structures of the new constituents were elucidated by chemical transformation and spectral studies including 1D ((1)H- and (13)C-NMR) and 2D ((1)H-(1)H correlation spectroscopy (COSY), nuclear Overhauser effect spectroscopy (NOESY), (1)H-(1)H total correlation spectroscopy (TOCSY), J-resolved, (1)H-detected heteronuclear multiple quantum coherence (HMQC), and heteronuclear multiple bond connectivity (HMBC)) NMR spectroscopy. 相似文献
378.
Jamila Javid Aziz-ur-Rehman Muhammad A. Abbasi Sabahat Z. Siddiqui Javed Iqbal Naeem A. Virk Shahid Rasool Hira A. Ali Muhammad Ashraf Wardah Shahid Safdar Hussain Syed A. Ali Shah 《Journal of heterocyclic chemistry》2021,58(1):93-110
A comparative microwave assisted and conventional synthetic strategies were applied to synthesize heterocyclic 1,3,4-oxadiazole analogues as active anti-enzymatic agents. Green synthesis of compound 1 was achieved by stirring 4-methoxybenzenesulfonyl chloride ( a ) and ethyl piperidine-4-carboxylate ( b ). Compound 1 was converted into respective hydrazide ( 2 ) by hydrazine and then into 1,3,4-oxadiazole ( 3 ) by CS2 on reflux. The electrophiles, N-alkyl/aralkyl/aryl-2-bromopropanamides ( 6a–p ) were synthesized and converted to N-alkyl/aralkyl/aryl-2-propanamide derivatives ( 7a–p ) by reaction with 3 under green chemistry. Microwave assisted method was found to be effective relative to conventional method. 13C-NMR, 1H-NMR and IR techniques were availed to corroborate structures of synthesized compounds and then subjected to screening against lipoxygenase (LOX), α-glucosidase, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. A number of compounds presented better potential against these enzymes. The most active compounds against LOX and α-glucosidase enzymes were subjected to molecular docking study to explore their interactions with the active sites of the enzymes. 相似文献
379.
Shivani T. Gajusingh Nasiruddin Shaikh Kamran Siddiqui 《Experimental Thermal and Fluid Science》2010,34(5):590-602
An experimental study was conducted to investigate the impact of a rectangular baffle inside a square channel. PIV was used to measure the two-dimensional velocity fields. The measurements were conducted for two Reynolds numbers in the fully turbulent regime. The changes to the flow structure due to the insertion of a baffle were quantified by a direct comparison with the flow structure in the absence of a baffle, under similar conditions. Results show that the turbulent velocities are enhanced by a factor of two to three and the rates of energy production and dissipation are enhanced by more than an order of magnitude when a baffle is inserted in the channel. Significant enhancement of turbulence was observed in a region up to two times the baffle height immediately downstream of the baffle and the thickness of this layer increased to three times the baffle height further downstream of the baffle. 相似文献
380.
The objective of the present work was to investigate the effects of pH, ions, and excipients on the in vitro lipolysis of self-emulsifying drug delivery systems (SEDDS). Studies were performed in bio-relevant media using a pH stat autotitrator for analysis. The results demonstrated that alkaline media were essential for lipolysis, which was enhanced by divalent CaCl2 ions and medium chain glycerides. Monovalent NaCl and the hydrophile-lipophile balance (HLB) of the surfactant had insignificant effect on lipolysis. Consequently, it was concluded that the activity of lipase, at an optimum pH of 6.5, is the predominant factors for digestion of SEDDS. 相似文献