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81.
We report on the fabrication of a surface‐enhanced Raman scattering (SERS) platform, comprised of a three‐dimensional (3D) porous eggshell membrane (ESM) scaffold decorated with Ag nanoparticles (NPs). Both native and treated ESM were used, where the treated ESM pore size and fiber crossing density was controlled by timed exposure to hydrogen peroxide (H2O2). Ag NPs were synthesized in situ by reduction of silver nitrate with ascorbic acid. Our results demonstrate that H2O2‐treated Ag‐ESM provides a more densely packed 3D network of active material, which leads to consistently higher SERS enhancement than untreated Ag‐ESM substrates. 相似文献
82.
83.
Chien-Tai Tsai Ricardo Morales-Rodriguez Gürkan Sin Anne S. Meyer 《Applied biochemistry and biotechnology》2014,172(6):2815-2837
The objective of this study is to perform a comprehensive enzyme kinetics analysis in view of validating and consolidating a semimechanistic kinetic model consisting of homogeneous and heterogeneous reactions for enzymatic hydrolysis of lignocellulosic biomass proposed by the U.S. National Renewable Energy Laboratory (Kadam et al., Biotechnol Prog 20(3):698–705, 2004) and its variations proposed in this work. A number of dedicated experiments were carried out under a range of initial conditions (Avicel® versus pretreated barley straw as substrate, different enzyme loadings and different product inhibitors such as glucose, cellobiose and xylose) to test the hydrolysis and product inhibition mechanisms of the model. A nonlinear least squares method was used to identify the model and estimate kinetic parameters based on the experimental data. The suitable mathematical model for industrial application was selected among the proposed models based on statistical information (weighted sum of square errors). The analysis showed that transglycosylation plays a key role at high glucose levels. It also showed that the values of parameters depend on the selected experimental data used for parameter estimation. Therefore, the parameter values are not universal and should be used with caution. The model proposed by Kadam et al. (Biotechnol Prog 20(3):698–705, 2004) failed to predict the hydrolysis phenomena at high glucose levels, but when combined with transglycosylation reaction(s), the prediction of cellulose hydrolysis behaviour over a broad range of substrate concentrations (50–150 g/L) and enzyme loadings (15.8–31.6 and 1–5.9 mg protein/g cellulose for Celluclast and Novozyme 188, respectively) was possible. This is the first study introducing transglycosylation into the semimechanistic model. As long as these type of models are used within the boundary of their validity (substrate type, enzyme source and substrate concentration), they can support process design and technology improvement efforts at pilot and full-scale studies. 相似文献
84.
Kang-Chieh Lo Chiao-Yin Sun Yu-Ju Ding Jen-Ning Tsai Kai-Ping Chang Yi-En Wen Wan-Ling Chang Shin C. Chang Ming-Fu Chang Yun-Hsin Wang Yau-Hung Chen 《Research on Chemical Intermediates》2014,40(6):2177-2185
Benzo(a)pyrene is a chemical produced during the process of making fried, roasted, and smoked foods. It remains unclear whether benzo(a)pyrene affects the early development of human organs. In this study, we used the transgenic zebrafish line Tg(wt1b:GFP) as a model to assess benzo(a)pyrene-induced kidney malformation. By soaking zebrafish embryos in benzo(a)pyrene at various doses (2, 20, and 200 ppb), only a minor effect on the survival rate was detected (0 ppb: 97.8 ± 1.9 %; 2–200 ppb: 89.1 ± 5.8–91.5 ± 8.3 %). However, benzo(a)pyrene significantly affected the development of the kidney (malformation rates ranges from 50.0 ± 3.5 to 77.4 ± 5.3 %). Various abnormalities, such as unusual curving of pronephric tubes, swollen glomerulus, and incomplete development of pronephric ducts, were observed. This study provides a rapid and effective protocol for the evaluation of the notable effects of benzo(a)pyrene on embryonic kidney development. 相似文献
85.
Hweiyan Tsai Hsiao-Ching Hu Chih-Chung Hsieh Yi-Hsuan Lu Chien-Hong Chen Chwan-Bor Fuh 《中国化学会会志》2020,67(1):152-159
Chloramphenicol (CAP) is a veterinary antibiotic that has been banned due to its severe side effects in humans. Through the application of manure, veterinary antibiotics can enter the soil, where they can be taken up by crops and vegetables and pose a potential health hazard to humans. Thus, it is highly desirable to develop a rapid and sensitive tool for on-site detection of CAP to ensure food safety and to control the abuse of antibiotics. To this end, nitrogen-doped graphene quantum dots (N-GQDs) were successfully prepared via microwave-assisted synthesis using citric acid and urea as carbon and nitrogen sources, respectively. Analytical results suggested that the interaction between N-GQDs and CAP could occurs via π-π stacking, which quenched N-GQD fluorescence. CAP spiked into chicken feed could be rapidly extracted with ethanol and quantified based on N-GQD fluorescence quenching without further separation. This method showed good recovery (97–102.6%), a low detection limit (1.8 ppm), and was not affected by interference from florfenicol, and thiamphenicol, legal substitute antibiotics. This method has excellent potential for determination of CAP in livestock feed and soil. 相似文献
86.
Jae Won Chang Mohammed Bhuiyan Hsiu‐Ming Tsai Hannah J. Zhang Gang Li Shaghayegh Fathi David C. McCutcheon Lara Leoni Richard Freifelder Chin‐Tu Chen Raymond E. Moellering 《Angewandte Chemie (International ed. in English)》2020,59(35):15161-15165
Herein, we report the development of an 18F‐labeled, activity‐based small‐molecule probe targeting the cancer‐associated serine hydrolase NCEH1. We undertook a focused medicinal chemistry campaign to simultaneously preserve potent and specific NCEH1 labeling in live cells and animals, while permitting facile 18F radionuclide incorporation required for PET imaging. The resulting molecule, [18F]JW199, labels active NCEH1 in live cells at nanomolar concentrations and greater than 1000‐fold selectivity relative to other serine hydrolases. [18F]JW199 displays rapid, NCEH1‐dependent accumulation in mouse tissues. Finally, we demonstrate that [18F]JW199 labels aggressive cancer tumor cells in vivo, which uncovered localized NCEH1 activity at the leading edge of triple‐negative breast cancer tumors, suggesting roles for NCEH1 in tumor aggressiveness and metastasis. 相似文献
87.
Chia-Yu Hung Chih-Han Chang Tzu-Jung Lin Hsin-Hui Yi Nian-Zhen Tsai Yu-Ru Chen Yng-Tay Chen 《Molecules (Basel, Switzerland)》2022,27(3)
Acrylamide (ACR) is present in high-temperature-processed high-carbohydrate foods, cigarette smoke, and industrial pollution. Chronic exposure to ACR may induce neurotoxicity from reactive oxygen species (ROS); however, the mechanisms underlying ACR-induced neurotoxicity remain unclear. We studied 28-day subacute ACR toxicity by repeatedly feeding ACR (0, 15, or 30 mg/kg) to rats. We conducted RNA sequencing and Western blot analyses to identify differences in mRNA expression in the blood and in protein expression in the brain tissues, respectively, of the rats. AQP4 transient transfection was performed to identify potential associations with protein regulation. The rats treated with 30 mg/kg ACR exhibited hind-limb muscle weakness. Matrix metalloproteinase (MMP9) expression was higher in the ACR-treated group than in the control group. ACR induced MMP-9 and AQP4 protein expression in the brain tissues of the rats, which subsequently presented with neurotoxicity. In the in vitro study, Neuro-2a cells were transiently transfected with AQP4, which inhibited MMP-9 and TNF receptor-associated factor 6 (TRAF6) expression, and inhibited ACR induced expression of TRAF6, IκBα, and nuclear factor κB (NFκB). Using a combination of in vivo and in vitro experiments, this study revealed that depressive symptoms associated with ACR-induced neurotoxicity are associated with downregulation of AQP4 and induction of the TRAF6 pathway. 相似文献
88.
K.B. Ibrahim W.-N. Su M.-C. Tsai A.W. Kahsay S.A. Chala M.K. Birhanu J.-F. Lee B.J. Hwang 《Materials Today Chemistry》2022
Developing oxygen evolution reaction (OER) electrocatalyst based on earth-abundant materials holds great promise for ascertaining water-splitting to surmount its deprived kinetics. In this regard, NiFe-LDH (layered double hydroxide) receives considerable attention owing to their layered structure. However, they still suffer from poor electronic conductivity and structural stability. We combined NiFe-LDH nanosheets with Magnéli phase Ti4O7 into a heterostructured composite. A series of analyses reveal that decorating Ti4O7 facilitates charge transfer to enhance the conductivity of NiFe-LDH-Ti4O7. During electrochemical measurement, Ni2+ is transformed to metastable Ni3+ (Ni (OH)→ NiOOH) before the OER onset potential. Thus, the presence of Ni3+ as the main active sites could improve the chemisorption of OH? to facilitate OER. As a result, the NiFe-LDH-Ti4O7 catalyst delivers as low as onset potential (1.43 V). Combining the holey structure (NiFe-LDH and Ti4O7) and the defect engineering generated on NiFe-LDH-Ti4O7 as a synergistic effect improves the OER performance. The inclusion of Ti4O7 in the composite leads to more vacancy sites, as evidenced by the extended X-ray absorption fine structure (EXAFS) analysis. The obtained defective structure with a low coordination environment would improve the electronic conductivity and facilitate the adsorption process of H2O onto metal cations, thereby increasing the intrinsic catalytic activity of NiOOH. The strong coupling of NiFe-LDH and Ti4O7 also increases the stability, and the heterostructured composite helps maintain the structural robustness of the LDH. 相似文献
89.
Wen-Shing Tsai Shah-Jye Tzeng Shih-Hung Chen Tzu-Shen Chien 《Optics Communications》2006,263(2):201-206
A bidirectional hybrid dense-wavelength-division-multiplexing (DWDM)-passive optical network (PON) employing optical injection locking technique on vertical-cavity surface-emitting lasers (VCSELs) and data comparator, as well as optical injection locking technique on distributed feedback laser diodes (DFB LDs) and amplitude/phase compensator is proposed and demonstrated. Improved performances of bit error rate (BER) and carrier-to-noise ratio/composite second order/composite triple beat (CNR/CSO/CTB) were observed in our proposed bidirectional hybrid DWDM-PON. Bidirectional transmission in bidirectional hybrid DWDM-PON architecture is a very attractive option, the capacity of the optical network can be expanded relatively easily by bidirectional transmission technology. 相似文献
90.
臧宏亮 叶沿林 李智焕 王建松 楼建玲 李奇特 葛愉成 杨晓菲 李晶 蒋伟 冯俊 刘强 杨彪 陈志强 刘洋 吴鸿毅 牛晨阳 李晨光 王春光 王翔 刘威 高见 余翰舟 马军兵 马朋 白真 杨彦云 金仕纶 卢飞 《中国物理C(英文版)》2018,42(7):074003-074003
An experiment for p(~(14)C,~(14)C~*→~(10)Be+α)p inelastic excitation and decay was performed in inverse kinematics at a beam energy of 25.3 Me V/u.A series of~(14)C excited states,including a new one at 18.3(1)Me V,were observed which decay to various states of the final nucleus of~(10)Be.A specially designed telescope system,installed around zero degrees,played an essential role in detecting the resonant states near theα-separation threshold.A state at 14.1(1)Me V is clearly identified,being consistent with the predicted band-head of the molecular rotational band characterized by theπ-bond linear chain configuration.Further clarification of the properties of this exotic state is suggested by using appropriate reaction tools. 相似文献