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排序方式: 共有175条查询结果,搜索用时 46 毫秒
31.
Madhu Santosh Ku Mutyala Deepika Bandhanadham Vijaya Rohini Pendyala 《Acta Mechanica Sinica》2009,25(1):1-12
Advances in the field of micro electro mechanical systems and their uses now offer unique opportunities in the design of ultrasensitive analytical tools. The analytical community continues to search for cost-effective, reliable, and even portable analytical techniques that can give reliable and fast response results for a variety of chemicals and biomolecules. Microcantilevers (MCLs) have emerged as a unique platform for label-free chem-sensor or bioassay. Several electronic designs, including piezoresistive, piezoelectric, and capacitive approaches, have been applied to measure the bending or frequency change of the MCLs upon exposure to chemicals. This review summarizes mechanical, fabrication, and electronics approaches to increase the sensitivity of MCL sensors. 相似文献
32.
Abdel Nasser B. Singab Nada M. Mostafa Iten M. Fawzy Deepika Bhatia Pooja Tanaji Suryawanshi Atul Kabra 《Molecules (Basel, Switzerland)》2022,27(19)
Maintaining healthy skin is important for a healthy body. At present, skin diseases are numerous, representing a major health problem affecting all ages from neonates to the elderly worldwide. Many people may develop diseases that affect the skin, including cancer, herpes, and cellulitis. Long-term conventional treatment creates complicated disorders in vital organs of the body. It also imposes socioeconomic burdens on patients. Natural treatment is cheap and claimed to be safe. The use of plants is as old as mankind. Many medicinal plants and their parts are frequently used to treat these diseases, and they are also suitable raw materials for the production of new synthetic agents. A review of some plant families, viz., Fabaceae, Asteraceae, Lamiaceae, etc., used in the treatment of skin diseases is provided with their most common compounds and in silico studies that summarize the recent data that have been collected in this area. 相似文献
33.
Kanchan Verma Yogesh Kumar Tailor Sarita Khandelwal Monu Agarwal Esha Rushell Sakshi Pathak Yogita Kumari Kamlendra Awasthi Mahendra Kumar 《应用有机金属化学》2020,34(10):e5836
An efficient and environmentally sustainable domino protocol has been presented for the synthesis of structurally diverse spiroannulated indolo[3,2-c]quinolines involving three component sequential reaction of phenylhydrazine, o-aminoacetophenone and cyclic ketones using nanostructured terbium doped TiO2 as recyclable and reusable heterogeneous catalyst. The nanostructured catalyst was synthesized successfully and characterized by X-ray Diffraction (XRD), transmission electron microscopy (TEM), EDX and Fourier transform infra-red spectroscopy (FTIR). The substitution of Ti+4 with Tb+3 and the formation of Ti-O-Tb bonds as a result of doping of Terbium with TiO2 NPs increases the catalytic efficiency and facilitates the reaction to provide the products in excellent yields. The present protocol with special features; operational simplicity, atom-economy, mild reaction conditions, environmental sustainability and high synthetic efficiency with recyclability and reusability of catalyst has been reported for the first time to synthesize spiroannulated indoloquinolines and expecting to provide the library of promising new leads in drug discovery research. 相似文献
34.
Deepika Geedkar Ashok Kumar Gagandeep Kour Reen Pratibha Sharma 《Journal of heterocyclic chemistry》2020,57(4):1963-1973
Present paper elicits the multicomponent reaction (MCR) strategy assisted by titania nanoparticles hosted on silica (TiO2.SiO2 NPs) as heterogeneous catalyst to synthesize a series of pharmacologically significant 2,3-diaryl-3,4-dihydroimidazo[4,5-b]indole derivatives. To the best of our information, the use of isatin as one of the precursors was hitherto unreported. The decrease in reaction time, low catalyst loading, high product yield (up to 92%), and excellent reusability of the catalyst (up to 7 cycles) put this protocol under the umbrella of green chemistry tenets. Characterization of catalysts was achieved through a number of techniques viz., energy-dispersive X-ray (EDX) spectroscopy, field emission scanning electron microscopy (FESEM), powder X-ray diffraction (XRD), fourier transform infrared (FTIR) spectra of adsorbed pyridine, temperature-programmed desorption of ammonia, and porosity measurements by nitrogen adsorption (Brunauer–Emmett–Teller [BET] method). Also, the structures of synthesized compounds were corroborated on the basis of FTIR, nuclear magnetic resonance (NMR), mass, and elemental analyses data. 相似文献
35.
Deepika Kathuria Sumit S. Chourasiya Sanjay K. Mandal Asit K. Chakraborti Uwe Beifuss Prasad V. Bharatam 《Tetrahedron》2018,74(23):2857-2864
Treatment of 1,3-diaryl-propene-2-one with aminoguanidine under acidic conditions for a short reaction period (1?h) delivers - in accordance with a literature report - the corresponding guanylhydrazones. However, when the reaction time was increased to 12?h, formation of the ring annulated product 4,5-dihydro-1H-pyrazole-1-carboximidamide was observed. This is the first case of ring-chain isomerism in conjugated guanylhydrazones. The acyclic conjugated guanylhydrazone and the corresponding annulated product (4,5-dihydro-1H-pyrazole-1-carboximidamide) could be clearly distinguished by means of UV and NMR spectroscopy. The formation of the ring isomer was further confirmed by single crystal XRD analysis. The time-dependent 1H NMR study indicated the gradual transformation of the open-chain compound into the cyclic one. The mechanistic insights into the formation of these two products were explored using quantum chemical methods which revealed that the ring isomer is thermodynamically more stable than the open-chain isomer by 6–11?kcal/mol and the barrier for cyclization was found to be 31.37?kcal/mol. 相似文献
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38.
Cellulose - In situ modification of bacterial cellulose (BC) allows structural and morphological tuning which determines the crucial properties such as water absorption/retention and rheological... 相似文献
39.
A complete mass spectral fragmentation pattern of naturally abundant pentagermane is presented together with the parent mass spectrum of hexagermane. The mass spectrum of pentagermane shows a fragmentation pattern of the five different types of ions with the following relative order of intensities: M3 > M4 > M2 > M5 > M1. The base peak of pentagermane lies at m/e 222 in the Ge3Hx=0→8 + region and not in the parent region. The base peak of hexagermane in the parent region lies at m/e 440. The precise centers of the three metastable regions of pentagermane lie at m/e 95.51, m/e 165.55 and m/e 237.47 respectively. 相似文献