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排序方式: 共有328条查询结果,搜索用时 15 毫秒
321.
Majid M. Heravi Samaheh Sadjadi Hossein A. Oskooie Rahim Hekmatshoar Fatemeh F. Bamoharram 《中国化学会会志》2008,55(4):842-845
3H‐1,5‐benzodiazepines were synthesized by the condensation of o‐phenylendiamine and various 1,3‐diketones in the presence of various heteropolyacid (HPA) catalysts under mild conditions in very good yields and with high selectivity. 相似文献
322.
323.
Dr. Ceri Hammond Dr. Robert L. Jenkins Dr. Nikolaos Dimitratos Dr. Jose Antonio Lopez‐Sanchez Dr. Mohd Hasbi ab Rahim Dr. Michael M. Forde Adam Thetford Dr. Damien M. Murphy Dr. Henk Hagen Dr. Eric E. Stangland Prof. Jacob M. Moulijn Dr. Stuart H. Taylor Dr. David J. Willock Prof. Graham J. Hutchings 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(49):15557-15557
324.
A sensitive hydrogen peroxide (H2O2) biosensor was developed based on a reduced graphene oxide|carbon ceramic electrode (RGO|CCE) modified with cadmium sulfide‐hemoglobin (CdS‐Hb). The electron transfer kinetics of Hb were promoted due to the synergetic function of RGO and CdS nanoparticles. The transfer coefficient (α) and the heterogeneous electron transfer rate constant (ks) were calculated to be 0.54 and 2.6 s?1, respectively, indicating a great facilitation achieved in the electron transfer between Hb and the electrode surface. The biosensor showed a good linear response to the reduction of H2O2 over the concentration range of 2–240 µM with a detection limit of 0.24 µM (S/N=3) and a sensitivity of 1.056 µA µM?1 cm?2. The high surface coverage of the CdS‐Hb modified RGO|CCE (1.04×10?8 mol cm?2) and a smaller value of the apparent Michaelis? Menten constant (0.24 mM) confirmed excellent loading of Hb and high affinity of the biosensor for hydrogen peroxide. 相似文献
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326.
Rahim GhadariFatemeh Hajishaabanha Mojtaba MahyariAhmad Shaabani Hamid Reza Khavasi 《Tetrahedron letters》2012,53(31):4018-4021
A facile and straightforward procedure for the synthesis of spiro-benzo[b]acridine-6,2′-furan derivatives via the reaction between benzo[b]acridine-6,11-dione, electron-deficient acetylenic compounds, and an isocyanide is described. The benzo[b]acridine-6,11-dione is obtained from the reaction between 2-(aminomethyl)aniline and 2-hydroxynaphthalene-1,4-dione via an unexpected reaction pathway. The products are synthesized in medium to high yields and no complicated purification is required. 相似文献
327.
M. Fill F. Felder M. Rahim A. Khiar H. Zogg 《Applied physics. B, Lasers and optics》2012,109(3):403-406
We present continuously tunable Vertical External Cavity Surface Emitting Lasers (VECSEL) in the mid-infrared. The structure based on IV?CVI semiconductors is epitaxially grown on a Si-substrates. The VECSEL emit one single mode, which is mode hop-free tunable over 50?C100?nm around the center wavelength. In this work, two different devices are presented, emitting at 3.4???m and 3.9???m, respectively. The lasers operate near room temperature with thermoelectric stabilization. They are optically pumped, yielding an output power >10?mWp. The axial symmetric emission beam has a half divergence angle of <3.3°. 相似文献
328.
Muhammad Arif Rahim Ullah Maaz Ahmad Ahmad Ali Zahid Ullah Mohammad Ali Fakhria A. Al-Joufi Muhammad Zahoor Hassan Sher 《Molecules (Basel, Switzerland)》2022,27(11)
Biologically synthesized silver nanoparticles are emerging as attractive alternatives to chemical pesticides due to the ease of their synthesis, safety and antimicrobial activities in lower possible concentrations. In the present study, we have synthesized silver nanoparticles (AgNPs) using the aqueous extract of the medicinal plant Euphorbia wallichii and tested them against the plant pathogenic bacterium Xanthomonas axonopodis, the causative agent of citrus canker, via an in vitro experiment. The synthesized silver nanoparticles were characterized by techniques such as UV-Vis spectroscopy, Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction analysis and transmission electron microscopy. Moreover, the plant species were investigated for phenolics, flavonoids and antioxidant activity. The antioxidant potential of the extract was determined against a DPPH radical. The extract was also evaluated for phenolic compounds using the HPLC technique. The results confirmed the synthesis of centered cubic, spherical-shaped and crystalline nanoparticles by employing standard characterization techniques. A qualitative and quantitative phytochemical analysis revealed the presence of phenolics (41.52 mg GAE/g), flavonoids (14.2 mg QE/g) and other metabolites of medicinal importance. Different concentrations (1000 µg/mL to 15.62 µg/mL—2 fold dilutions) of AgNPs and plant extract (PE) alone, and both in combination (AgNPs-PE), exhibited a differential inhibition of X. axanopodis in a high throughput antibacterial assay. Overall, AgNPs-PE was superior in terms of displaying significant antibacterial activity, followed by AgNPs alone. An appreciable antioxidant potential was recorded as well. The observed antibacterial and antioxidant potential may be attributed to eight phenolic compounds identified in the extract. The Euphorbia wallichii leaf-extract-induced synthesized AgNPs exhibited strong antibacterial activity against X. axanopodis, which could be exploited as effective alternative preparations against citrus canker in planta in a controlled environment. In addition, as a good source of phenolic compounds, the plant could be further exploited for potent antioxidants. 相似文献