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101.
Ka Ming Ma Cheok Man Chan Stephen Wai Cheung Chung Yuk Yin Ho 《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2013,30(1):12-16
This study evaluated the dietary exposure of secondary school students in Hong Kong to benzoic acid from pre-packaged non-alcoholic beverages. Exposure was estimated using local food consumption data of secondary school students obtained by a semi-quantitative food frequency questionnaire in 2000 and the benzoic acid level detected in pre-packaged beverages, including soft drink (both diet/light and regular types), fruit juice, soy milk, Chinese tea and coffee/tea) available locally in late 2006. The estimated dietary exposure to benzoic acid from pre-packaged beverages of average and high consumers (95th percentile) was 0.31 and 0.97 mg kg?1 bw day?1, respectively. These exposures accounted for 6.1 and 19.3% of the acceptable daily intake (ADI: 0–5 mg kg?1 bw) of benzoic acid for average and high consumers, respectively. As in other countries, soft drinks contributed most to dietary exposure to benzoic acid from pre-packaged beverages in Hong Kong. 相似文献
102.
慢性累积γ照射诱发小鼠体细胞和生殖细胞染色体畸变的比较研究 总被引:1,自引:0,他引:1
慢性累积γ照射0~2.1Gy,生殖细胞染色体畸变率随照射剂量增大而增加,拟合成直线回归方程y=-0.1133+1.162D(r=0.9962,P<0.05)。体细胞与照射剂量之间无相关性。各剂量点畸变率,体细胞大于生殖细胞畸变值。照后40d检查两类细胞染色体易位率,则生殖细胞又大于体细胞2.6倍,与急性照射规律相似。 相似文献
103.
Organic Solar Cells: A Tetraphenylethylene Core‐Based 3D Structure Small Molecular Acceptor Enabling Efficient Non‐Fullerene Organic Solar Cells (Adv. Mater. 6/2015) 下载免费PDF全文
104.
Je Young Yoo Joon Hyun Shin Gilson Khang Hyung Sik Shin Soon Hong Yuk Yong Sik Kim Moon Suk Kim John M. Rhee Hai Bang Lee 《应用聚合物科学杂志》2007,104(2):1019-1025
For the treatment of osteomyelitis and the prevention of infections after orthopedic surgery, topically implantable gentamicin sulfate (GS)‐loaded poly(D ,L ‐lactide‐co‐glycolide) microparticles (GSMP) containing glycolide monomer (GM), as a biodegradable and nontoxic material, were prepared by melt‐extrusion method without organic solvent for controlled release. After preparation of polymer blend, the powders of different size (90–1200 μm) were obtained by means of freezer‐mill. The influences of GM and particle size were investigated on the GS release patterns. GSMP containing GM (in case of 10% loaded) showed a near‐zero order release from 2 to 7 days with the initial burst. GM affected to increase of GS release rate during the in vitro release test. The pH variations of the media were investigated to determine effect of GM on pH drop of media. The morphological evaluations, change of molecular weight, and thermal property of microparticles were characterized by scanning electron microscope, gel permeation chromatography, and differential scanning calorimeter, respectively. Bacterial inhibition zone test was established to identify antibiosis of GS. It showed antibiotic areas except control sample. From these results, the authors expected that GSMP containing GM would be a good dosage form as a topically implantable device that can get rid of lag period of GSMP. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1019–1025, 2007 相似文献
105.
Eunmi Cho Jung Geon Son Chan Beom Park In Kim Dohun Yuk Jin-Seong Park Jin Young Kim Sang-Jin Lee 《Advanced functional materials》2023,33(25):2370155
Increase in incident light and surface modification of the charge transport layer are powerful routes to achieve high-performance efficiency of perovskite solar cells (PSCs) by improving the short-circuit current density (JSC) and charge transport characteristics, respectively. However, few techniques are studied to reduce reflection loss and simultaneously improve the electrical performance of the electron transport layer (ETL). Herein, an inclined fluorine (F) sputtering process to fabricate high-performance PSCs is proposed. The proposed process simultaneously implements the antireflection effect of F coating and the effect of F doping on a TiO2 ETL, which increases the amount of light transmitted into the PSC due to the extremely low refractive index (≈1.39) and drastically improves the electrical properties of TiO2. Consequently, the JSC of the F coating and doping perovskite solar cell (F-PSC) increased from 25.05 to 26.01 mA cm−2, and the power conversion efficiency increased from 24.17% to 25.30%. The unencapsulated F-PSC exhibits enhanced air stability after 900 h of exposure to ambient environment atmosphere (30% relative humidity, 25 °C under dark condition). The inclined F sputtering process in this study can become a universal method for PSCs from the development stage to commercialization in the future. 相似文献
106.
Lang Nan Man Yuk Alison Lai Matthew Yuk Heng Tang Yau Kei Chan Leo Lit Man Poon Ho Cheung Shum 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(9)
Droplet‐based microfluidic techniques are extensively used in efficient manipulation and genome‐wide analysis of individual cells, probing the heterogeneity among populations of individuals. However, the extraction and isolation of single cells from individual droplets remains difficult due to the inevitable sample loss during processing. Herein, an automated system for accurate collection of defined numbers of droplets containing single cells is presented. Based on alternate sorting and dispensing in three branch channels, the droplet number can be precisely controlled down to single‐droplet resolution. While encapsulating single cells and reserving one branch as a waste channel, sorting can be seamlessly integrated to enable on‐demand collection of single cells. Combined with a lossless recovery strategy, this technique achieves capture and culture of individual cells with a harvest rate of over 95%. The on‐demand droplet collection technique has great potential to realize quantitative processing and analysis of single cells for elucidating the role of cell‐to‐cell variations. 相似文献
107.
Kwon Gyoo Taik Yuk Hyun-Gyun Lee Su Jung Chung Yi Hyung Jang Han Su Yoo Jong-Sang Cho Kyung-Hoon Kong Hyunseok Shin Daekeun 《Food science and biotechnology》2020,29(4):531-537
Food Science and Biotechnology - The objective of this study was to evaluate the effect of yellow mealworm (Tenebrio molitor L.) exuviae (ME) given as a prebiotic in 20% of the diet fed to BALB/c... 相似文献
108.
Lee Hae-Sook Choi Hee-Eun Choi Ung-Kyu Yuk Hyun-Gyun 《Food science and biotechnology》2020,29(10):1439-1445
Food Science and Biotechnology - This study aimed to evaluate three standard enrichment broth preparations for the recovery of healthy and chlorine-injured E. coli O157:H7 cells in kimchi. The... 相似文献
109.
Carlos A. Ramirez-Mondragon Megin E. Nguyen Jozafina Milicaj Bakar A. Hassan Frank J. Tucci Ramaiah Muthyala Jiali Gao Erika A. Taylor Yuk Y. Sham 《International journal of molecular sciences》2021,22(9)
It has long been understood that some proteins undergo conformational transitions en route to the Michaelis Complex to allow chemistry. Examination of crystal structures of glycosyltransferase enzymes in the GT-B structural class reveals that the presence of ligand in the active site triggers an open-to-closed conformation transition, necessary for their catalytic functions. Herein, we describe microsecond molecular dynamics simulations of two distantly related glycosyltransferases that are part of the GT-B structural superfamily, HepI and GtfA. Simulations were performed using the open and closed conformations of these unbound proteins, respectively, and we sought to identify the major dynamical modes and communication networks that interconnect the open and closed structures. We provide the first reported evidence within the scope of our simulation parameters that the interconversion between open and closed conformations is a hierarchical multistep process which can be a conserved feature of enzymes of the same structural superfamily. Each of these motions involves of a collection of smaller molecular reorientations distributed across both domains, highlighting the complexities of protein dynamic involved in the interconversion process. Additionally, dynamic cross-correlation analysis was employed to explore the potential effect of distal residues on the catalytic efficiency of HepI. Multiple distal nonionizable residues of the C-terminal domain exhibit motions anticorrelated to positively charged residues in the active site in the N-terminal domain involved in substrate binding. Mutations of these residues resulted in a reduction in negatively correlated motions and an altered enzymatic efficiency that is dominated by lower Km values with kcat effectively unchanged. The findings suggest that residues with opposing conformational motions involved in the opening and closing of the bidomain HepI protein can allosterically alter the population and conformation of the “closed” state, essential to the formation of the Michaelis complex. The stabilization effects of these mutations likely equally influence the energetics of both the ground state and the transition state of the catalytic reaction, leading to the unaltered kcat. Our study provides new insights into the role of conformational dynamics in glycosyltransferase’s function and new modality to modulate enzymatic efficiency. 相似文献
110.
Min-Jeong Kim Min Da Jeong Qianwang Zheng Hyun-Gyun Yuk 《Food science and biotechnology》2021,30(4):609
This study investigated the antimicrobial activity of 405 nm light-emitting diode (LED) with and without riboflavin against Listeria monocytogenes in phosphate buffered saline (PBS) and on smoked salmon at different storage temperatures and evaluated its impact on food quality. The results show that riboflavin-mediated LED illumination in PBS 25 °C significantly inactivated L. monocytogenes cells by 6.2 log CFU/mL at 19.2 J/cm2, while illumination alone reduced 1.9 log CFU/mL of L. monocytogenes populations at 57.6 J/cm2. L. monocytogenes populations on illuminated smoked salmon decreased by 1.0–2.2 log CFU/cm2 at 1.27–2.76 kJ/cm2 at 4, 12, and 25 °C, regardless of the presence of riboflavin. Although illumination with and without riboflavin caused the lipid peroxidation and color change in smoked salmon, this study demonstrates the potential of a 405 nm LED to preserve the smoked salmon products, reducing the risk of listeriosis. 相似文献