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排序方式: 共有241条查询结果,搜索用时 15 毫秒
61.
Farzad Nikpour Sajjad Mohebbi Touraj Paibast Mahdi Beigvand 《Monatshefte für Chemie / Chemical Monthly》2008,139(6):663-667
A regio- and stereoselective synthesis of functionalized 4,5-disubstituted oxazolidin-2-ones is reported with moderate to
good yields from the reaction of α-epoxyketones with urea in the presence of p-toluenesulfonic acid as the catalyst.
Correspondence: Farzad Nikpour, Department of Chemistry, Faculty of Sciences, University of Kurdistan, P.O. Box 66315-416,
Sanandaj, Iran. 相似文献
62.
Slide-away discharges are achieved by decreasing the plasma density or ramping down the plasma current in runaway discharges in the HT-7 tokamak. In the case of plasma current ramp down, the ratio of the electron plasma frequency to the electron cyclotron frequency is higher than in the stationary pulses when the discharge goes into a slide-away regime. The instability regime is characterized by relaxations in the electron cyclotron emission due to relativistic anomalous Doppler effect which transfers energy from parallel to perpendicular motion. The triggering of relativistic anomalous Doppler effect at higher density by ramping down of plasma current may provide a alternative runaway energy control scenario. 相似文献
63.
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65.
Merve Kara Sajjad Dadashi‐Silab Yusuf Yagci 《Macromolecular rapid communications》2015,36(23):2070-2075
A new phenacyl‐type photoinitiator based on ethyl carbazole as a long wavelength photoinitiator is developed for free radical polymerization. Phenacyl ethyl carbazolium hexafluoroantimonate (PECH) photoinitiator is synthesized in a two‐step, one‐pot manner by quaternizing ethyl carbazole with phenacyl bromide and subsequent ion exchange reaction with potassium hexafluoroantimonate. Under irradiation, PECH tends to undergo homolytic bond cleavage bringing about initiating free radicals. However, as evidenced by cyclic voltammetry and real‐time photobleaching studies, formation of initiating cationic species is highly unlikely as the photochemically formed charged carbazole units tend to couple.
66.
Khalid M. Khan Nida Ambreen Muhammad Taha Sobia A. Halim Zaheer-ul-Haq Shagufta Naureen Saima Rasheed Shahnaz Perveen Sajjad Ali Mohammad Iqbal Choudhary 《Journal of computer-aided molecular design》2014,28(5):577-585
Using structure-based virtual screening approach, a coumarin derivative (1) was identified as β-glucuronidase inhibitor. A focused library of coumarin derivatives was synthesized by eco-benign version of chemical reaction, and all synthetic compounds were characterized by using spectroscopy. These compounds were found to be inhibitor of β-glucuronidase with IC50 values in a micromolar range. All synthetic compounds exhibited interesting inhibitory activity against β-glucuronidase, however, their potency varied substantially from IC50 = 9.9–352.6 µM. Of twenty-one compounds, four exhibited a better inhibitory profile than the initial hit 1. Interestingly, compounds 1e, 1k, 1n and 1p exhibited more potency than the standard inhibitor with IC50 values 34.2, 21.4, 11.7, and 9.9 µM, respectively. We further studied their dose responses and also checked our results by using detergent Triton ×-100. We found that our results are true and not affected by detergent. 相似文献
67.
Hassan Rakhshandeh Hamed Rajabi Khasevan Anella Saviano Mohammad Reza Mahdinezhad Vafa Baradaran Rahimi Sajjad Ehtiati Leila Etemad Alireza Ebrahimzadeh-bideskan Francesco Maione Vahid Reza Askari 《Molecules (Basel, Switzerland)》2022,27(18)
Background: Type-one diabetes (T1D), a chronic autoimmune disease with marked inflammatory responses, is associated with infertility complications and implications. Based on the anti-diabetic, antioxidant, and anti-hyperlipidemic potential of Portulaca oleracea (PO), this study aimed to evaluate the protective effect of this plant extract on streptozotocin-induced type-I-diabetes-associated reproductive system dysfunction and inflammation. Methods: Male rats were randomly divided into four experimental groups: control, diabetic, and treatment/s (PO extract at 100 or 300 mg/kg/daily). Then food and water consumption, body, testis and epididymis weights, histopathological evaluation, seminiferous tubules diameter, sperm count and motility, glucose levels, sex hormones, and inflammatory and oxidative stress markers were evaluated. Results: Our results showed that streptozotocin-induced diabetes significantly increased food and water consumption; increased glucose, MDA, TGF-β1, and TNF-α levels; and decreased the seminiferous tubules diameter, sperm count and motility, levels of LH, testosterone, total thiol, VEGF, and SOD activity. Interestingly, PO extract (phytochemically characterized by using liquid chromatography–mass spectrometry to detect bioactive molecules) significantly ameliorated these parameters and histopathological indexes’ damage in rats. Conclusion. Even if more preclinical assessments are needed to better characterize the mechanism/s of action, the results of this study will pave the way for the rational use of PO on diabetic-associated clinical complications and implications. 相似文献
68.
Sajjad Ahmad Momin Khan Najeeb Ur Rehman Muhammad Ikram Sadia Rehman Mahboob Ali Jalal Uddin Ajmal Khan Aftab Alam Ahmed Al-Harrasi 《Molecules (Basel, Switzerland)》2022,27(20)
Background: Hydrazides play a vital role in making biologically active compounds in various fields of chemistry. These determine antioxidant, antidepressant, antimalarial, anti-inflammatory, antiglycating, and antimicrobial activity. In the present study, twenty-three new N′ benzylidene-4-(tert-butyl)benzohydrazide derivatives (4–26) were synthesized by the condensation of aromatic aldehydes and commercially available 4-(tert-butyl)benzoic acid. All the target compounds were successfully synthesized from good to excellent yield; all synthesized derivatives were characterized via spectroscopic techniques such as HREI-MS and 1H-NMR. Synthesized compounds were evaluated for in vitro urease inhibition. All synthesized derivatives demonstrated good inhibitory activities in the range of IC50 = 13.33 ± 0.58–251.74 ± 6.82 µM as compared with standard thiourea having IC50 = 21.14 ± 0.425 µM. Two compounds, 6 and 25, were found to be more active than standard. SAR revealed that electron donating groups in phenyl ring have more influence on enzyme inhibition. However, to gain insight into the participation of different substituents in synthesized derivatives on the binding interactions with urease enzyme, in silico (computer simulation) molecular modeling analysis was carried out. 相似文献
69.
Abdul Majid Amber Batool Salah Ud-Din Khan Sajjad Haider 《International journal of quantum chemistry》2019,119(14):e25924
First-principles calculations were performed to investigate the vibrational properties of monomers and dimers of titania, silica, and titania-silica hybrid clusters. Density functional theory-based formulism was employed to optimize the geometry at the B3LYP level and calculate the infrared and Raman spectra of the clusters by using the GGA-PBE exchange-correlation functional. It was found that the vibrational spectra of Ti2O4, Si2O4, and TiSiO4 hybrid clusters provide fingerprint information about structures and structural transitions during the formation of cluster structures. In the case of Si2O4 the mode at 410 cm−1 exhibited the largest vibration of Si atoms, whereas in the case of Ti2O4 the mode at 442 cm−1 exhibited the largest vibration of Ti atoms. The hybrid cluster TiSiO4 was structured using two different methods to explore the effects of starting geometry on the structures and vibrational modes of the clusters. The structural properties of the clusters remained unchanged but vibrational modes were found to be different. It is found that Si shows notable vibrations, but the metal atom Ti merely shows any vibration in the case of TiSiO4 hybrid clusters. The low and intermediate frequency modes were stiffened, whereas the three highest frequency modes were softened when the starting geometry of the hybrid clusters was changed from Si2O4 to Ti2O4. 相似文献
70.
Palladium and Fe3O4 nanoparticles were deposited on N‐(2‐aminoethyl)acetamide‐functionalized cellulose for use in a catalytic reaction. The catalyst was characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, X‐ray diffraction, energy‐dispersive X‐ray analysis and transmission electron microscopy, and applied in the oxidation reaction of ethylbenzene at 100 °C using H2O2. Styrene oxide was obtained as the sole product of the oxidation reaction during 24 h. This reaction has some advantages such as one‐pot transformation of ethylbenzene to styrene oxide, high yield, excellent selectivity and magnetically recoverable catalyst. Also, the recovered catalyst could be used in the oxidation reaction four times without decrease in yield. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献