排序方式： 共有105条查询结果，搜索用时 15 毫秒
71.
Elnaz Yaghini Katharina F. Pirker Christopher W. M. Kay Alexander M. Seifalian Alexander J. MacRobert 《Small (Weinheim an der Bergstrasse, Germany)》2014,10(24):5106-5115
Photocatalytic generation of reactive oxygen species (ROS) from quantum dots (QDs) has been widely reported yet quantitative studies of ROS formation and their quantum yields are lacking. This study investigates the generation of ROS by water soluble PEGylated CdSe/ZnS QDs with red emission. PEGylation of QDs is commonly used to confer water solubility and minimise uptake by organs of the reticuloendothelial system; therefore studies of ROS formation are of biomedical relevance. Using non‐photolytic visible wavelength excitation, the superoxide anion radical is shown to be the primary ROS species generated with a quantum efficiency of 0.35%. The yield can be significantly enhanced in the presence of the electron donor, nicotinamide adenine dinucleotide (NADH), as demonstrated by oxygen consumption measurements and electron paramagnetic resonance spectroscopy with in situ illumination. Direct production of singlet oxygen is not detectable from the QDs alone. A comparison is made with ROS generation by the same QDs complexed with a sulfonated phthalocyanine which can generate singlet oxygen via Förster resonance energy transfer between the QDs and the phthalocyanine. 相似文献
72.
Gianguido Ramis Elnaz Bahadori Ilenia Rossetti 《International Journal of Hydrogen Energy》2021,46(22):12105-12116
The photoreforming of glucose has been studied over TiO2 photocatalyst with different photoreactors, focusing on the effect of the reaction conditions: temperature, pressure, catalyst and substrate concentration. The effect of pressure was particularly significant, decreasing hydrogen evolution rate, but improving the conversion of the substrate. Furthermore, pressure moderately higher than ambient allowed to operate at high temperature (80 °C), boosting hydrogen productivity. Most experiments were carried out on glucose photoreforming, but, for the first time, the photoconversion of levulinic acid was investigated, as an interesting product of biomass hydrolysis under harsh conditions. Levulinic acid led to the production of ethane and ethylene in gas phase, interpreted according to a preliminary hypothesis of the photoconversion mechanism. High hydrogen productivity was achieved, in most cases higher than the literature benchmark. 相似文献
73.
Moosavifar Maryam Zarrini Gholamreza Mashmool-barjasteh Elnaz 《Journal of Inorganic and Organometallic Polymers and Materials》2022,32(3):781-790
Journal of Inorganic and Organometallic Polymers and Materials - This study aims at the preparation of antimicrobial nanoparticles hybrid based on silver (Ag) doped Zn1?xCuxO. Zn1?xCuxO... 相似文献
74.
75.
New compounds of rare earth complex oxides with perovskite structure in a combination of La with Eu ions and Mn with Zn ions,
La1−x
Eu
x
Mn0·9Zn0·1O3+d
(LEMZ) (0·0 ≤ x ≤ 0·32) in A and B sites, respectively were synthesized. X-ray powder diffraction (XRD), fourier transform infrared spectroscopy
(FT-IR) and photoluminescence spectra (PL) were used to characterize the resulting nanoparticles. The powder X-ray diffraction
peaks could be indexed as a rhombohedral cell. The results of FT-IR spectra were in agreement with those of XRD. High-quality
nanopowders with controlled stoichiometry and microstructure were prepared at a temperature range of 700–800°C for 6 h, with
mean particle sizes of ∼ 17·5 nm. Photoluminescence measurements showed Eu3+ ions characteristic red emission in crystalline LEMZ powders due to the 5
D
0 → 7
F
J (J = 0–6) transitions of the 4f electrons of Eu3+ ions. The structure, homogeneity and particle size of the obtained compounds during different stages were investigated by
scanning electron microscopy (SEM). 相似文献
76.
Seyed Mohammad Bagher Hashemi Fakhri Shahidi Seyed Ali Mortazavi Elnaz Milani Zarrin Eshaghi 《International Journal of Dairy Technology》2016,69(4):550-558
The oxidative stability and lipid modifications of Doogh prepared with Lactobacillus plantarum LS5 and control Doogh were compared during storage for 22 days. In vitro scavenging activity against 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) free radicals showed that L. plantarum LS5 had radical scavenging activities (49.6%). Peroxide value, conjugated diene value and anisidine value measurements in Doogh lipid samples in combination with Fourier transform infrared spectroscopy demonstrated that Doogh prepared with L. plantarum LS5 was more stable than the control against formation of primary and secondary oxidation products. Furthermore, higher concentrations of short‐chain fatty acids (butyric and caproic) and unsaturated fatty acids were found in Doogh treated with L. plantarum LS5. Changes in the thermograms of all samples were also observed. Results of differential scanning calorimetry indicated that melting points of lipids from treated Doogh were lower than for the control. It was concluded that L. plantarum LS5 could be used as a natural preservative in functional dairy products and could beneficially affect the consumer by providing dietary sources of antioxidants. 相似文献
77.
Marzieh Jamalabadi Elnaz Firouzmand Iman Sharifi Mahyar Naraghi 《Asian journal of control》2024,26(3):1346-1363
This paper studies the trajectory tracking of a constrained mobile robot under slippery conditions. The goal is to propose a controller for real-time operations of time-varying dynamics with insignificant execution time. Therefore, a Laguerre-based model predictive control (LMPC) is designed, and robustness is provided with an linear matrix inequality (LMI)-feedback controller. Moreover, a recursive least square (RLS) algorithm with a forgetting factor is utilized to identify the required parameters of the LMI-based controller. LMPC and LMI-based controller stability is achieved with suboptimal theory and Lyapunov function, respectively. This algorithm separates the nominal system and introduces new dynamics containing uncertainties. Furthermore, LMPC is removed from the online calculation, which dramatically reduces computation burden and time; consequently, online computation is dedicated to determining the LMI feedback. Simulations are provided to compare the proposed robust controller to its not robust counterpart. Finally, it is demonstrated that this controller diminishes the execution time considerably, making it incomparable to previous robust MPC strategies. 相似文献
78.
Nishir Mehta Shahensha Shaik Alisha Prasad Ardalan Chaichi Sushant P. Sahu Qianglin Liu Syed Mohammad Abid Hasan Elnaz Sheikh Fabrizio Donnarumma Kermit K. Murray Xing Fu Ram Devireddy Manas Ranjan Gartia 《Advanced functional materials》2021,31(43):2103955
Stem cell-based therapies carry significant promise for treating human diseases. However, clinical translation of stem cell transplants for effective treatment requires precise non-destructive evaluation of the purity of stem cells with high sensitivity (<0.001% of the number of cells). Here, a novel methodology using hyperspectral imaging (HSI) combined with spectral angle mapping-based machine learning analysis is reported to distinguish differentiating human adipose-derived stem cells (hASCs) from control stem cells. The spectral signature of adipogenesis generated by the HSI method enables identifying differentiated cells at single-cell resolution. The label-free HSI method is compared with the standard techniques such as Oil Red O staining, fluorescence microscopy, and qPCR that are routinely used to evaluate adipogenic differentiation of hASCs. HSI is successfully used to assess the abundance of adipocytes derived from transplanted cells in a transgenic mice model. Further, Raman microscopy and multiphoton-based metabolic imaging is performed to provide complementary information for the functional imaging of the hASCs. Finally, the HSI method is validated using matrix-assisted laser desorption/ionization-mass spectrometry imaging of the stem cells. The study presented here demonstrates that multimodal imaging methods enable label-free identification of stem cell differentiation with high spatial and chemical resolution. 相似文献
79.
80.
Ali Vahidifar Elnaz Esmizadeh Ehsan Rostami Saied Nouri Khorasani Denis Rodrigue 《Polymer Composites》2019,40(11):4289-4299
In this study, compression molding was used to produce elastomeric nanocomposite foams based on natural rubber (NR) with a hybrid reinforcing system containing organo‐modified nanoscale (NC) and nanocarbon black (NCB). The effect of NC content (0‐10 part per hundred rubber, phr) on the curing behavior, as well as the morphological and mechanical properties of elastomeric foams containing 10 phr of NCB was determined. Transmission electron microscopy and X‐ray diffraction results showed that NC exfoliation occurred at low NC concentration (less than 5 phr), while increasing NC content up to 5 phr led to aggregation. Rheological data revealed that increasing the NC content up to 10 phr gradually changed the curing parameters such as 50% shorter scorch and curing time, two times faster curing rate, as well as higher initial (35%) and final (35%) torque. Scanning electron microscopy analysis also showed that increasing NC content from 0 to 5 phr produced foams with more uniform small cells, while 7 phr of NC changed the foam structure into two areas composed of different cell sizes and different cell densities. Higher NC content (10 phr) led to broken cell walls. With nanoparticles, higher foam modulus (83%) and hardness (104%) were observed. Finally, NC addition was found to improve the NR's thermal and thermo‐oxidative resistance while the sound absorption coefficient was constant. 相似文献