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1.
Amphiphilic polymers consisting of a statistical distribution of octadecyl methacrylate (ODMA) and acrylic acid in respective molar ratios of 83-22 and 17-78 mol% and in a molecular-weight range of 2.35-4.70᎒4 gmol-1 have been synthesized. The series of polymers consisting of various mole fractions of ODMA and acrylic acid are expected to exhibit unique characteristics resembling ionomer to hydrophobically modified polyelectrolytes. The changes in the I3/I1 emission intensity ratios of pyrene, occurring in the presence of tetrahydrofuran (THF) solutions of the polymers have been taken as the main basis for inferring solution structures. The polymers are found to form random-coil to collapsed-coil/aggregated structures in THF solvent depending on the copolymer compositions. The polymer consisting of 83 mol% ODMA and 17 mol% acrylic acid behaves as an ionomer, capable of forming collapsed-coil structures at concentrations of 0.02 gml-1 and above as shown by a very high I3/I1 of 1.20 (I3/I1 of pyrene in THF is 0.85). In contrast, the poly(octadecyl methacrylate) homopolymer and the sets of copolymers consisting of a very high proportion of acrylic acid to an extent of 73 mol% and above contribute to almost negligible or very small changes in I3/I1 similar to the homopolymer, poly(octadecyl methacrylate), suggesting the formation of random-coil structures. 相似文献
2.
Rajakumar Govindasamy Vaishnavi Raja Sonalika Singh Mydhili Govindarasu Sulthana Sabura Kaliaperumal Rekha V. Devi Rajeswari Salman S. Alharthi Manju Vaiyapuri Rajagopal Sudarmani S. Jesurani Baskar Venkidasamy Muthu Thiruvengadam 《Molecules (Basel, Switzerland)》2022,27(17)
The advanced technology for synthesizing nanoparticles utilizes natural resources in an environmentally friendly manner. Additionally, green synthesis is preferred to chemical and physical synthesis because it takes less time and effort. The green synthesis of cobalt oxide nanoparticles has recently risen due to its physico-chemical properties. In this study, many functional groups present in Psidium guajava leaf extracts are used to stabilize the synthesis of cobalt oxide nanoparticles. The biosynthesized cobalt oxide nanoparticles were investigated using UV-visible spectroscopic analysis. Additionally, Fourier-transform infrared spectroscopy revealed the presence of carboxylic acids, hydroxyl groups, aromatic amines, alcohols and phenolic groups. The X-ray diffraction analysis showed various peaks ranging from 32.35 to 67.35°, and the highest intensity showed at 36.69°. The particle size ranged from 26 to 40 nm and confirmed the average particle size is 30.9 nm. The green synthesized P. guajava cobalt oxide nanoparticles contain cobalt as the major abundant element, with 42.26 wt% and 18.75 at% confirmed by the EDAX techniques. SEM images of green synthesized P. guajava cobalt oxide nanoparticles showed agglomerated and non-uniform spherical particles. The anti-bacterial activity of green synthesized P. guajava cobalt oxide nanoparticles was evaluated against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli with a 7 to 18 mm inhibitory zone. The photocatalytic activity was evaluated using green synthesized P. guajava cobalt oxide nanoparticles and observed 79% of dye degradation. The MTT assay of P. guajava cobalt oxide nanoparticles showed an excellent cytotoxic effect against MCF 7 and HCT 116 cells compared to normal cells. The percentage of cell viability of P. guajava cobalt oxide nanoparticles was observed as 90, 83, 77, 68, 61, 58 and 52% for MCF-7 cells and 82, 70, 63, 51, 43, 40, and 37% for HCT 116 cells at the concentration of 1.53, 3.06, 6.12, 12.24, 24.48, 50, and 100 μg/mL compared to control cells. These results confirmed that green synthesized P. guajava cobalt oxide nanoparticles have a potential photocatalytic and anti-bacterial activity and also reduced cell viability against MCF-7 breast cancer and HCT 116 colorectal cancer cells. 相似文献
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4.
V. N. Vijayakumar T. R. Rajasekaran K. Baskar 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2017,91(13):2578-2584
A novel supramolecular liquid crystal (LC) is synthesized from the binary complex of 4-decyloxy benzoic acid and cholesteryl acetate. Fourier transform infrared (FTIR) spectroscopic study confirms the formation of intermolecular hydrogen bond between the mesogens. Various mesophases and corresponding textural changes in the complex are observed by comparing with its constituents through polarizing optical microscopic (POM) studies. The thermal stability factor of smectic phase for present complex is calculated. An interesting observation of present work is that investigation of extended thermal span of mesomorphic phases, decreased enthalpy, a nematic phase with a high clearing point and a low melting point. This is due to an arrangement of molecular reorientations and the development of new associations by hydrogen bonding. Optical tilt angle for smectic C phase is determined and the same is fitted to a power law. 相似文献
5.
Durairaj Gopalakrishnan Santhanam Srinath Baburaj Baskar Nattamai S.P. Bhuvanesh Mani Ganeshpandian 《应用有机金属化学》2019,33(3)
Two organometallic Ru(II)‐p‐cymene complexes of the type [Ru(η6‐p‐cymene)(L)Cl]PF6 1 and 2 , where L is N,N‐bis(4‐isopropylbenzylidene)ethane‐1,2‐diamine (bien, L1 ) or N,N‐bis (pyren‐2‐ylmethylene)ethane‐1,2‐diamine (bpen, L2 ) have been prepared and characterized well. Because of appended pyrenyl groups in coordinated bpen ligand, the complex 2 exhibits higher DNA and protein binding than complex 1 in which isopropylbenzyl groups are incorporated. Interestingly, the luminescent characteristic complex 2 is unique in displaying DNA cleavage after light activation by UVA light at 365 nm through oxygen dependent mechanism. AFM analysis attests the photo‐induced DNA fragmentation ability of complex 2 . Also, the complex 2 cleaves the protein after light exposure in a non‐specific manner suggesting that it can act as a protein photo cleaving agent. In contrast to the trend of DNA and protein interaction of complexes, the complex 1 exhibits cytotoxic activity against human breast carcinoma ( MCF‐7 ) and liver carcinoma ( HepG2 ) with potency higher than that of complex 2 due to enhanced hydrophobicity of isopropyl groups present in p‐cymene and bien ligands. Indeed, complex 2 is inactive against MCF‐7 and HepG2 cancer cell lines even up to 200 μM concentration. The AO/EB staining assay reveals that the complex 1 is able to induce late apoptotic mode of cell death in breast cancer cells, which is further confirmed by inter‐nucleosomal DNA cleavage. Furthermore, the complexes 1 and 2 are evaluated for their catalytic activities and found to be working well for the β‐carboline directed C–H arylation to afford the desired products in good yield (40–47%). 相似文献
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Vadapalli Chandrasekhar Viswanathan Baskar Ramamoorthy Boomishankar Selvarajan Nagendran 《Phosphorus, sulfur, and silicon and the related elements》2013,188(4-5):699-701
The reactions of n-butyl stannonic acid with(PhO) 2 P(O)H leads to the formation of a hexameric tin cage [{(n-BuSn) 3 (PhO) 3 O} 2 {HPO 3 } 4 ].This reaction involves an in situ P─O bond cleavage and the generation of a [HPO 3 ] 2? ion. A direct reaction of six equivalents of n-BuSnO(OH) acid with six equivalents of C 6 H 5 OH and four equivalents of H 3 PO 3 also leads to the formation of same cage structure. A tetranuclear organooxotin cage[(PhCH 2 ) 2 Sn 2 O(O 2 P(OH)-t-Bu) 4 ] 2 has been assembled by debenzylation involving the reaction of (PhCH 2 ) 2 SnCl 2 ,(PhCH 2 ) 2 SnO·H 2 O or (PhCH 2 ) 3 SnCl with two equivalents of t-BuP(O)OH 2 . A half-cage intermediate [(PhCH 2 ) 2 Sn 2 O(O 2 P(OH)-t-Bu) 4 ] has been detected. New organotin cations of the type [n-Bu 2 Sn(H 2 O) 4 ] 2+[2,5-Me 2 -C 6 H 3 SO 3 ]? 2 and {[n-Bu 2 Sn(H 2 O) 3 LSn(H 2 O) 3 (n-Bu) 2 ] 2+[1,5-(SO 3 ) 2 -C 10 H 6 ] 2?} have been obtained in the reactions of n-Bu 2 SnO or (n-Bu 3 Sn) 3 O with 2,5-dimethyl sulfonic acid and 1,5-naphthalene disulfonic acid respectively. These organotin cations form interesting supramolecular structures in the solid state as a result of O─H─···O hydrogen bonding. 相似文献
7.
M. V. Ramana Reddy A. B. Manjubhashini S. Reddy P. V. Ramana Reddy D. Baskar Reddy 《合成通讯》2013,43(15-16):1589-1596
The condensation of 2-phenylethanesulfonylacetic acid (4) with araldehydes (5) in presence of a base gave E-styryl-2-phenylethyl sulfones (6) which on dehydrogenation with DDQ (7) yielded E,E-bis-(styrl)sulfones (8). The 8 on treatment with dichlorotris(triphenyl-phosphine)ruthenium(II) catalyst resulted 1,4-diaryl-1,3-butadienes (9). The configurations of 6, 8 and 9 have been determined based on IR and 1H NMR spectral data. 相似文献
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A pair of kinematical conservation laws (KCL) in a ray coordinatesystem (,t) are the basic equations governing the evolutionof a moving curve in two space dimensions. We first study elementarywave solutions and then the Riemann problem for KCL when themetric g, associated with the coordinate designating differentrays, is an arbitrary function of the velocity of propagationm of the moving curve. We assume that m>1 (m is appropriatelynormalized), for which the system of KCL becomes hyperbolic.We interpret the images of the elementary wave solutions inthe (,t)-plane to the (x,y)-plane as elementary shapes of themoving curve (or a nonlinear wavefront when interpreted in aphysical system) and then describe their geometrical properties.Solutions of the Riemann problem with different initial datagive the shapes of the nonlinear wavefront with different combinationsof elementary shapes. Finally, we study all possible interactionsof elementary shapes. 相似文献
9.
纤维素酶是一种有效的纤维质类物质水解催化剂,工业应用时可通过固定化纤维素酶来降低其成本。本文将烟曲霉原变种JCF产生的纤维素酶固定在MnO2纳米颗粒上。 MnO2可提高纤维素酶的活性,并充当一个更好的载体。采用扫描电镜表征了所制MnO2纳米粒子及其负载纤维素酶的表面性质,以傅里叶变换红外光谱分析了固定在MnO2纳米粒子上纤维素酶的官能团性质。纤维素酶在MnO2纳米粒子上最大的固定化效率为75%。考察了固定化纤维素酶的活性、操作pH值、温度、热稳定性和重复使用性等性质。结果表明,所制固定化酶的稳定性比游离酶更高。固定于MnO2纳米粒子上的纤维素酶可用于纤维质类物质的水解反应,且能在较宽的温度和pH值范围内使用。表征结果证实了该催化剂具有非常高的催化纤维素类物质水解的活性。 相似文献
10.
A three-level central composite design of the Response Surface Methodology and the Artificial Neural Network-linked Genetic
Algorithm were applied to find the optimum operating conditions for enhanced production of l-asparaginase by the submerged fermentation of Aspergillus terreus MTCC 1782. The various effects of the operating conditions, including temperature, pH, inoculum concentration, agitation
rate, and fermentation time on the experimental production of l-asparaginase, were fitted to a second-order polynomial model and non-linear models using Response Surface Methodology and
the Artificial Neural Network, respectively. The Artificial Neural Network model fitted well, achieving a higher coefficient
of determination (R
2 = 0.999) than the second-order polynomial model (R
2 = 0.962). The l-asparaginase activity (38.57 IU s mL−1) predicted under the optimum conditions of 32.08°C, pH of 5.85, inoculum concentration of 1 vol. %, agitation rate of 123.5
min−1, and fermentation time of 55.1 h was obtained using the Artificial Neural Networklinked Genetic Algorithm in very close agreement
with the activity of 37.84 IU mL−1 achieved in confirmation experiments. 相似文献