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101.
Srnová-Sloufová I Vlcková B Snoeck TL Stufkens DJ Matĕjka P 《Inorganic chemistry》2000,39(16):3551-3559
Excitation profiles of SERS (surface-enhanced Raman scattering) and/or SERRS (surface-enhanced resonance Raman scattering) spectral bands of two forms of a Ag-bpy (bpy = 2,2'-bipyridine) surface complex and of [Ru(bpy)3]2+ on Ag nanoparticle (hydrosol) surfaces were determined from the spectra excited in the 458-600 nm region and are reported together with the FT-SERS spectra of the Ag-bpy surface complex and FT Raman spectra of [Ru(bpy)3] Cl2. Seven of the observed 11 fundamentals as well as their first overtones and combination bands are selectively enhanced in SERS of the Ag-bpy surface complex formed in the Ag colloid/HCl/bpy system. The profiles of these bands show a common maximum at approximately 540 nm. The selectively enhanced bands of the Ag-bpy surface complex have nearly the same wavenumbers as those enhanced in the SERRS and resonance Raman spectra of [Ru(bpy)3]2+ upon excitation close to the 453 nm maximum of its MLCT absorption band. Moreover, the intensity patterns of the bpy vibrations of the two species match both in resonance (541 nm excitation for Ag-bpy, 458 nm for [Ru(bpy)3]2+) and in off-resonance (458 and 1064 nm for Ag-bpy, 1064 nm for [Ru(bpy)3]2+). The distinct band shapes of the excitation profiles of the selectively enhanced vibrational modes of the Ag-bpy surface complex, as well as the observation of overtones and combination bands in the SERS spectra upon excitation into this "band", are interpreted in terms of a charge-transfer resonance contribution to the overall SERS enhancement. In view of the near-coincidence of the vibrational modes coupled to the resonant electronic transition of Ag-bpy with those coupled to the MLCT transition of [Ru(bpy)3]2+, the resonant electronic transition is tentatively assigned to a Ag metal to bpy (pi*) CT transition. 相似文献
102.
Farrah Syazana Khattulanuar Mahendran Sekar Shivkanya Fuloria Siew Hua Gan Nur Najihah Izzati Mat Rani Subban Ravi Kumarappan Chidambaram M. Yasmin Begum Abul Kalam Azad Srikanth Jeyabalan Arulmozhi Dhiravidamani Lakshmi Thangavelu Pei Teng Lum Vetriselvan Subramaniyan Yuan Seng Wu Kathiresan V. Sathasivam Neeraj Kumar Fuloria 《Molecules (Basel, Switzerland)》2022,27(3)
Cardiovascular disorders (CVDs) are the leading risk factor for death worldwide, and research into the processes and treatment regimens has received a lot of attention. Tilianin is a flavonoid glycoside that can be found in a wide range of medicinal plants and is most commonly obtained from Dracocephalum moldavica. Due to its extensive range of biological actions, it has become a well-known molecule in recent years. In particular, numerous studies have shown that tilianin has cardioprotective properties against CVDs. Hence, this review summarises tilianin’s preclinical research in CVDs, as well as its mechanism of action and opportunities in future drug development. The physicochemical and drug-likeness properties, as well as the toxicity profile, were also highlighted. Tilianin can be a natural lead molecule in the therapy of CVDs such as coronary heart disease, angina pectoris, hypertension, and myocardial ischemia, according to scientific evidence. Free radical scavenging, inflammation control, mitochondrial function regulation, and related signalling pathways are all thought to play a role in tilianin’s cardioprotective actions. Finally, we discuss tilianin-derived compounds, as well as the limitations and opportunities of using tilianin as a lead molecule in drug development for CVDs. Overall, the scientific evidence presented in this review supports that tilianin and its derivatives could be used as a lead molecule in CVD drug development initiatives. 相似文献
103.
Gizem Gülsoy Toplan Turgut Takn Gkalp can Fatih Gger Mine Kürküolu Aye Civa Gülay Ecevit-Gen Afife Mat Kemal Hüsnü Can Baer 《Molecules (Basel, Switzerland)》2022,27(6)
The potential applications of Achillea species in various industries have encouraged the examination of their phytochemical components along with their biological potential. In the present study, phenolic contents and essential oil compositions together with the in vitro biological activities of the aerial parts from Achillea biebersteinii Afan. and Achillea millefolium subsp. millefolium Afan. collected from Turkey were evaluated. Different solvent extracts (n-hexane, chloroform, methanol, water) were prepared and their antimicrobial, anticholinesterase, and antioxidant activities were studied. The LC-MS/MS results revealed the presence of 16 different phenolic compounds, including chlorogenic acid, rutin, quercetin, and luteolin glycosides, in methanolic extracts. According to GC-FID and GC/MS results, the primary components of the oils were identified as 1,8-cineole (32.5%), piperitone (14.4%), and camphor (13.7%) in A. biebersteinii and 1,8-cineole (12.3%) and β-eudesmol (8.9%) in A. millefolium subsp. millefolium. The infusion and methanolic extracts of both species were found to be rich in their total phenolic content as well as their antioxidant and anticholinesterase activity. In contrast, the n-hexane and chloroform extracts of both species showed strong antimicrobial activity with MIC values ranging from 15 to 2000 μg/mL. Our findings suggest that the investigated Achillea species could be evaluated as potent natural agents, and further studies into the promising extracts are needed. 相似文献
104.
105.
In several previous papers we have argued for a global and non-entropic approach to the problem of the arrow of time, according
to which the “arrow” is only a metaphorical way of expressing the geometrical time-asymmetry of the universe. We have also
shown that, under definite conditions, this global time-asymmetry can be transferred to local contexts as an energy flow that
points to the same temporal direction all over the spacetime. The aim of this paper is to complete the global and non-entropic
program by showing that our approach is able to account for irreversible local phenomena, which have been traditionally considered
as the physical origin of the arrow of time. 相似文献
106.
E. Drechsel O. Kallauner J. Matějka J. H. Chesters 《Analytical and bioanalytical chemistry》1939,117(9-10):379-379
107.
随机利率下的连续型生存年金 总被引:3,自引:0,他引:3
本文首次以连续型生存年金为对象,采用Wiener过程对利息力累积函数建模,得到了该利率模型下的连续型生存年金现值的各阶矩,并在一些特殊条件下得到了矩的简单表达式. 相似文献
108.
Wan Azelee Wan Abu Bakar Rusmidah Ali Abdul Aziz Abdul Kadir Salmiah Jamal Mat Rosid Nurul Shafeeqa Mohammad 《燃料化学学报》2012,40(7):822-830
A series of alumina supported cobalt oxide based catalysts doped with noble metals such as ruthenium and platinum were prepared by wet impregnation method.The variables studied were difference ratio and calcination temperatures.Pt/Co(10∶90)/Al2O3 catalyst calcined at 700 ℃ was found to be the best catalyst which able to convert 70.10% of CO2 into methane with 47% of CH4 formation at maximum temperature studied of 400 ℃.X-ray diffraction analysis showed that this catalyst possessed the active site Co3O4 in face-centered cubic and PtO2 in the orthorhombic phase with Al2O3 existed in the cubic phase.According to the FESEM micrographs,both fresh and spent Pt/Co(10∶90)/Al2O3 catalysts displayed small particle size with undefined shape.Nitrogen Adsorption analysis showed that 5.50% reduction of the total surface area for the spent Pt/Co(10∶90)/Al2O3 catalyst.Meanwhile,Energy Dispersive X-ray analysis(EDX) indicated that Co and Pt were reduced by 0.74% and 0.14% respectively on the spent Pt/Co(10∶90)/Al2O3catalyst.Characterization using FT-IR and TGA-DTA analysis revealed the existence of residual nitrate and hydroxyl compounds on the Pt/Co(10∶90)/Al2O3 catalyst. 相似文献
109.
Mat Mohamad Nur Hidayat Asmuin Nor Zelawati Md Basir Md Faisal Abbas Tehseen Mohd Kasihmuddin Mohd Shareduwan Goodarzi Marjan 《Journal of Thermal Analysis and Calorimetry》2021,143(3):2343-2354
Journal of Thermal Analysis and Calorimetry - In this paper, a numerical study was performed to examine the effect of divergent nozzle length of single-hose dry ice blasting on the development of... 相似文献
110.
Mat Mohamad Nur Hidayat Asmuin Nor Zelawati Md Basir Md Faisal Safaei Mohammad Reza Mohd Kasihmuddin Mohd Shareduwan Ahmad Khairuddin Taufiq Khairi Godarzi Marjan 《Journal of Thermal Analysis and Calorimetry》2021,144(6):2159-2173
Journal of Thermal Analysis and Calorimetry - One of the important parameters in developing dry ice blasting nozzle is the high-speed dry ice pellets. However, many studies focus primarily only on... 相似文献