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排序方式: 共有342条查询结果,搜索用时 15 毫秒
321.
Gnül YENLMEZ FT Sergen YILMAZ Nagihan BAYIK Elif ENKUYTU Esra Nur KAYA Mahmut DURMU Mustafa BULUT 《Turkish Journal of Chemistry》2020,44(1):64
The newly synthesized cyclotriphosphazene cored coumarin chemosensors 5, 6, and 7 were successfully characterized by 1 H NMR, 31 P NMR, and MALDI-TOF mass spectrometry. Additionally, the photophysical and metal sensing properties of the targeted compounds were determined by fluorescence spectroscopy in the presence of various metals (Li + , Na + , K + , Cs + , Mg 2+ , Ca 2+ , Ba 2+ , Cr 3+ , Mn 2+ , Fe 3+ , Co 2+ , Al 3+ , Hg + , Cu 2+ , Zn 2+ , Ag + , and Cd 2+ ) . The fluorescence titration results showed that compounds 5, 6, and 7 could be employed as fluorescent chemosensors for Fe 3+ ions with high sensitivity. The complex stoichiometry between final cyclotriphosphazene chemosensors and Fe 3+ ions was also determined by Job’s plots. 相似文献
322.
Nik Nur Hakimah Nik Salleh Farah Amna Othman Nur Alisa Kamarudin Suat Cheng Tan 《Molecules (Basel, Switzerland)》2020,25(23)
In Southeast Asia, traditional medicine has a longestablished history and plays an important role in the health care system. Various traditional medicinal plants have been used to treat diseases since ancient times and much of this traditional knowledge remains preserved today. Oroxylum indicum (beko plant) is one of the medicinal herb plants that is widely distributed throughout Asia. It is a versatile plant and almost every part of the plant is reported to possess a wide range of pharmacological activities. Many of the important bioactivities of this medicinal plant is related to the most abundant bioactive constituent found in this plant—the baicalein. Nonetheless, there is still no systematic review to report and vindicate the biological activities and therapeutic potential of baicalein extracted from O. indicum to treat human diseases. In this review, we aimed to systematically present in vivo and in vitro studies searched from PubMed, ScienceDirect, Scopus and Google Scholar database up to 31 March 2020 based on keywords “Oroxylum indicum” and “baicalein”. After an initial screening of titles and abstracts, followed by a full-text analysis and validation, 20 articles that fulfilled all the inclusion and exclusion criteria were included in this systematic review. The searched data comprehensively reported the biological activities and therapeutic potential of baicalein originating from the O. indicum plant for anti-cancer, antibacterial, anti-hyperglycemia, neurogenesis, cardioprotective, anti-adipogenesis, anti-inflammatory and wound healing effects. Nonetheless, we noticed that there was a scarcity of evidence on the efficacy of this natural active compound in human clinical studies. In conclusion, this systematic review article provides new insight into O. indicum and its active constituent baicalein as a prospective complementary therapy from the perspective of modern and scientific aspect. We indicate the potential of this natural product to be developed into more conscientious and judicious evidencebased medicine in the future. However, we also recommend more clinical research to confirm the efficacy and safety of baicalein as therapeutic medicine for patients. 相似文献
323.
Nur Ezwan Anis Muhd Subuhi Salwani Md Saad Nur Nadhirah Mohamad Zain Vuanghao Lim Mazidatulakmam Miskam Sazlinda Kamaruzaman Muggundha Raoov Noorfatimah Yahaya 《Journal of separation science》2020,43(16):3294-3303
In this work, a simple, fast, sensitive, and environmentally friendly method was developed for preconcentration and quantitative measurement of bisphenol A in water samples using gas chromatography with mass spectrometry. The preconcentration approach, namely biosorption‐based dispersive liquid‐liquid microextraction with extractant removal by magnetic nanoparticles was performed based on the formation of microdroplet of rhamnolipid biosurfactant throughout the aqueous samples, which accelerates the mass transfer process between the extraction solvent and sample solution. The process is then followed by the application of magnetic nanoparticles for easy retrieval of the analyte‐containing extraction solvent. Several important variables were optimized comprehensively including type of disperser solvent and desorption solvent, rhamnolipid concentration, volume of disperser solvent, amount of magnetic nanoparticles, extraction time, desorption time, ionic strength, and sample pH. Under the optimized microextraction and gas chromatography with mass spectrometry conditions, the method demonstrated good linearity over the range of 0.5–500 µg/L with a coefficient of determination of R2 = 0.9904, low limit of detection (0.15 µg/L) and limit of quantification (0.50 µg/L) of bisphenol A, good analyte recoveries (84–120%) and acceptable relative standard deviation (1.8–14.9%, n = 6). The proposed method was successfully applied to three environmental water samples, and bisphenol A was detected in all samples. 相似文献
324.
The heat-driven solid-state transformations of K salts of the Na-encapsulated Preyssler-type phosphotungstates, K14[P5W30O110Na(side)(H2O)] and K14[P5W30O110Na(center)], are reported herein. K14[P5W30O110Na(side)(H2O)] contains one Na+ in one of the side cavities and a coordinating H2O molecule while K14[P5W30O110Na(center)] contains one Na+ in the central cavity. The heating of K14[P5W30O110Na(side)(H2O)] produces [P5W30O110Na(center)]14–, [P5W30O110K(center)]14–, and [P5W30O110K(side)2]13–. [P5W30O110K(center)]14– and [P5W30O110K(side)2]13– contain mono-K+ in the central cavity and di-K+ in both side cavities, respectively. The heating of potassium salt of [P5W30O110Na(center)]14– produces [P5W30O110K(center)]14– and [P5W30O110K(side)2]13–. These results indicate that heating, at 200–500 °C, causes the migrations of Na+ and K+, without the collapse of the molecule. K14[P5W30O110Na(side)(H2O)] was successfully converted to K12Na[P5W30O110K(side)2] by repeated solid-state heating, which was periodically interrupted by dissolution, in H2O, and drying. 相似文献
325.
Nasir NM Rahmani M Shaari K Ee GC Go R Kassim NK Muhamad SN Iskandar MJ 《Molecules (Basel, Switzerland)》2011,16(11):8973-8980
The air-dried powdered stem bark of Calophyllum nodusum (Guttiferea) collected from Sandakan (Sabah, Malaysia), was extracted sequentially with hexane, chloroform and methanol. The solvents were removed by rotary evaporator to give dark viscous extracts. Detailed and repeated chromatographic separation of the extracts lead to isolation of two new xanthones, identified as nodusuxanthone and trapezifolixanthone A. Other common terpenoids such as betulinic acid, lupeol, stigmasterol and friedelin were also isolated from the extracts and identified. The structures of the compounds were established by detailed spectral analysis and comparison with previously reported data. 相似文献
326.
Zaman S. Zainelabdin A. Amin G. Nur O. Willander M. 《Applied Physics A: Materials Science & Processing》2011,104(4):1203-1209
Hybrid light emitting diodes (LEDs) based on zinc oxide (ZnO) nanorods and polymers (single and blended) were fabricated and
characterized. The ZnO nanorods were grown by the chemical bath deposition method at 50°C. Three different LEDs, with blue
emitting, orange-red emitting or their blended polymer together with ZnO nanorods, were fabricated and studied. The current–voltage
characteristics show good diode behavior with an ideality factor in the range of 2.1 to 2.27 for all three devices. The electroluminescence
spectrum (EL) of the blended device has an emission range from 450 nm to 750 nm, due to the intermixing of the blue emission
generated by poly(9,9-dioctylfluorene) denoted as PFO with orange-red emission produced by poly(2-methoxy-5(20-ethyl-hexyloxy)-1,4-phenylenevinylene)
1,4-phenylenevinylene) symbolized as MEH PPV combined with the deep-band emission (DBE) of the ZnO nanorods, i.e. it covers
the whole visible region and is manifested as white light. The CIE color coordinates showed bluish, orange-red and white emission
from the PFO, MEH PPV and blended LEDs with ZnO nanorods, respectively. These results indicate that the choice of the polymer
with proper concentration is critical to the emitted color in ZnO nanorods/p-organic polymer LEDs and careful design should
be considered to obtain intrinsic white light sources. 相似文献
327.
In this article, a novel (G'/G)-expansion method is proposed to search for the traveling wave solutions of nonlinear evolution equations. We construct abundant traveling wave solutions involving parameters to the Boussinesq equation by means of the suggested method. The performance of the method is reliable and useful, and gives more general exact solutions than the existing methods. The new (G'/G)-expansion method provides not only more general forms of solutions but also cuspon, peakon, soliton, and periodic waves. 相似文献
328.
Pre-ceramic polymers have previously been shown to be polymeric precursors to silicon carbide, diamond and diamond-like carbon. Here, we report the synthesis of a pre-ceramic polymer, poly(silyne-co-hydridocarbyne), which was electrochemically synthesized from one monomer containing both silicon and carbon in its structure. The polymer is soluble in common solvents such as CHCl3, CH2Cl2 and THF. Since the polymer contains both silyne and carbyne on its backbone, it can be easily converted to silicon carbide upon heating under an ambient inert atmosphere, or to SiO2 under ambient air atmosphere. Poly(silyne-co-hydridocarbyne) was characterized with UV/Vis spectroscopy, FTIR, 1H-NMR, GPC and Raman spectroscopy. Conversion of the polymer to SiC ceramic was accomplished by heating at 1000 and 750°C under an argon atmosphere and characterized with optical microscopy, SEM, X-Ray and Raman spectroscopies. 相似文献
329.
Pratama Jujur Wibawa Muhammad Nur Mukhammad Asyari Wijanarka Wijanarka Heru Susanto Heri Sutanto Hadi Nur 《Molecules (Basel, Switzerland)》2021,26(13)
This research aimed to enhance the antibacterial activity of silver nanoparticles (AgNPs) synthesized from silver nitrate (AgNO3) using aloe vera extract. It was performed by means of incorporating AgNPs on an activated carbon nanoparticle (ACNPs) under ultrasonic agitation (40 kHz, 2 × 50 watt) for 30 min in an aqueous colloidal medium. The successful AgNPs synthesis was clarified with both Ultraviolet-Visible (UV-Vis) and Fourier Transform Infrared (FTIR) spectrophotometers. The successful AgNPs–ACNPs incorporation and its particle size analysis was performed using Transmission Electron Microscope (TEM). The brown color suspension generation and UV-Vis’s spectra maximum wavelength at around 480 nm confirmed the existence of AgNPs. The particle sizes of the produced AgNPs were about 5 to 10 nm in the majority number, which collectively surrounded the aloe vera extract secondary metabolites formed core-shell like nanostructure of 8.20 ± 2.05 nm in average size, while ACNPs themselves were about 20.10 ± 1.52 nm in average size formed particles cluster, and 48.00 ± 8.37 nm in average size as stacking of other particles. The antibacterial activity of the synthesized AgNPs and AgNPs-immobilized ACNPs was 57.58% and 63.64%, respectively (for E. coli); 61.25%, and 93.49%, respectively (for S. aureus). In addition, when the AgNPs-immobilized ACNPs material was coated on the cotton and polyester fabrics, the antibacterial activity of the materials changed, becoming 19.23% (cotton; E. coli), 31.73% (polyester; E. coli), 13.36% (cotton; S. aureus), 21.15% (polyester; S. aureus). 相似文献
330.
Aisyah Nur Hanis Azhar Nurul Aini Amran Suzana Yusup Mohd Hizami Mohd Yusoff 《Molecules (Basel, Switzerland)》2022,27(15)
2-acetyl-1-pyrroline (2AP) is the compound that gives out the typical aroma and flavour of pandan leaves (Pandanus amaryllifolius Roxb.). This research incorporates ultrasonic extraction to extract the aromatic compound in pandan leaves. The parameters varied in this study are the extraction time, sonicator amplitude, concentration of solvent and the mass of pandan leaves. The experiment was conducted using a central composite design (CCD) model generated by the response surface methodology (RSM). From the extraction process, it can be deduced that the effect of leaves’ mass is comparably higher than other parameters, while sonicator amplitude gives the most negligible impact on the process. The obtained p-value was 0.0014, which was less than 0.05. The high R-squared 0.9603 and adjusted R-squared 0.8809 indicate the model is well agreed with the actual data. The optimal control variables of ultrasonic extraction of 2AP are at an extraction time of 20 min, 60% of solvent concentration, amplitude of 25% and 12.5 g of pandan leaves, which produced 60.51% of yield of the extract and 1.43 ppm of 2AP. It is found that the mass of pandan leaves and the concentration of solvent have a significant impact on the extraction process of 2AP. 相似文献