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21.
The synthesis and characterization of the resin Amberlite XAD-4 functionalized with 2,6-pyridinedicarboxaldehyde and its application in an on-line system for the preconcentration of cadmium, cobalt, copper, lead and manganese prior to determination using flame atomic absorption spectrometry (FAAS) is proposed. Metal ions retained on the modified resin were eluted using 1.0 mol L−1 HNO3 solution and aspirated directly to the nebulizer–burner system of a FAAS instrument using a flow injection system. Detection limits (3σ) were determined to be 0.13 μg L−1 for Cd, 0.29 μg L−1 for Cu, 0.23 μg L−1 for Mn, 0.58 μg L−1 for Co and 2.19 μg L−1 for Pb using a 10 mL of water sample loading volume. The limits of detection would be 100 times higher with units of μg kg−1 for the solid samples in which their dilution ratios as (volume/weight) were 100. Enrichment factors ranged from 23.6 to 28.9 (for Co and Mn, respectively). The proposed method was successfully applied to determination of the analytes in natural water samples and certified reference materials. 相似文献
22.
Daniele S. Wikoff Darin C. Bennett Gregory P. Brorby Kara S. Franke 《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2020,37(5):804-814
ABSTRACTRed Lake Diatomaceous Earth (DE) is a naturally occurring blend of diatomaceous earth and calcium bentonite that can be used as an anti-caking agent in animal feed and contains naturally occurring dioxins. A quantitative risk assessment was conducted to assess potential human health risk associated with consumption of edible tissues from livestock exposed to dioxins via feed containing Red Lake DE. Empirical data characterising the transfer of dioxins to eggs and other tissues in chickens demonstrate that resulting concentrations in eggs are lower than those found in the general food supply. These data also provided product-specific input for a risk assessment conducted both with default parameters and with media-specific input from the feed study. Results demonstrate that exposure to dioxins in edible tissue from livestock that consumed Red Lake DE in feed would not be associated with an increased risk to humans. Findings from this assessment highlight the utility and importance of accounting for bioavailability as part of health-based risk assessment and provide information critical to risk managers in determining the safe use of Red Lake DE as an anticaking agent in livestock and pet feed. 相似文献
23.
Min Tian Kara L. Kliewer Michelle L. Asp Michael B. Stout Martha A. Belury 《Molecular nutrition & food research》2011,55(2):268-277
Scope: Cancer cachexia is characterized by muscle and adipose tissue wasting caused partly by chronic, systemic inflammation. Conjugated linoleic acids (CLAs) are a group of fatty acids with various properties including anti‐inflammatory cis9, trans11 (c9t11)‐CLA and lipid‐mobilizing trans10, cis12 (t10c12)‐CLA. The purpose of this study was to test whether dietary supplementation of a c9t11‐CLA‐rich oil (6:1 c9t11:t10c12) could attenuate wasting of muscle and adipose tissue in colon‐26 adenocarcinoma‐induced cachexia in mice. Methods and results: Loss of body weight, muscle and adipose tissue mass caused by tumors were not rescued by supplementation with the c9t11‐CLA‐rich oil. In quadriceps muscle, c9t11‐CLA‐rich oil exacerbated tumor‐induced gene expression of inflammatory markers tumor necrosis factor‐α, IL‐6 receptor and the E3 ligase MuRF‐1 involved in muscle proteolysis. In epididymal adipose tissue, tumor‐driven delipidation and atrophy was aggravated by the c9,t11‐CLA‐rich oil, demonstrated by further reduced adipocyte size and lower adiponectin expression. However, expression of inflammatory cytokines and macrophage markers were not altered by tumors, or CLA supplementation. Conclusion: These data suggest that addition of c9t11‐CLA‐rich oil (0.6% c9t11, 0.1% t10c12) in diet did not ameliorate wasting in mice with cancer cachexia. Instead, it increased expression of inflammatory markers in the muscle and increased adipose delipidation. 相似文献
24.
Chemometric approach to evaluate trace metal concentrations in some spices and herbs 总被引:1,自引:0,他引:1
Herbs (mint, thyme and rosemary) and spices (black pepper, chili pepper, cinnamon, cumin, sweet red pepper and turmeric) were analysed using atomic spectrometry and then subjected to chemometric evaluation in an attempt to classify them using their trace metallic analyte concentrations (As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Sr and Zn). Trace metals in acid digests of these materials were determined using both inductively coupled plasma-atomic emission spectrometry and inductively coupled plasma-mass spectrometry. The chemometric techniques of principal component analysis (PCA), linear discriminant analysis (LDA) and cluster analysis (CA) were used for the classification studies. These herbs and spices were classified into five groups by PCA and CA. When the results of these techniques were compared with those from LDA, it was found that all group members determined by PCA and CA are in the predicted group that 100.0% of original grouped cases correctly classified by LDA. 相似文献
25.
Ali Can Zaman Cem B. Üstündağ Ali Çelik Alpagut Kara Figen Kaya Cengiz Kaya 《Journal of the European Ceramic Society》2010,30(16):3351-3356
Preparation, structure and properties of hydrothermally treated carbon nanotube/boehmite (CNT/γ-AlOOH) and densification with spark plasma sintering of Al2O3 and CNT/Al2O3 nanocomposites were investigated. Hydrothermal synthesis was employed to produce CNT/boehmite from an aluminum acetate (Al(OH)(C2H3O2)2) and multiwall-CNTs mixture (200 °C/2 h.). TEM observations revealed that the size of the cubic shape boehmite particles lies around 40 nm and the presence of the interaction between surface functionalized CNTs and boehmite particles acts to form ‘nanocomposite particles’. Al2O3 and CNT/Al2O3 compact bodies were formed by means of spark plasma sintering (SPS) at 1600 °C for 5 min using an applied pressure of 50MPa resulting in the formation of stable α-Al2O3 phase and CNT–alumina compacts with nearly full density. It was also found that CNTs tend to locate along the alumina grain boundaries and therefore inhibit the grain coarsening and cause inter-granular fracture mode. The DC conductivity measurements reveal that the DC conductivity of CNT/Al2O3 is 10?4 S/m which indicate that there is a 4 orders of magnitude increase in conductivity compared to monolithic Al2O3. The results of the microhardness tests indicate a slight increase in hardness for CNT/Al2O3 (28.35 GPa for Al2O3 and 28.57 GPa for CNT/Al2O3). 相似文献
26.
Seed oils of Origanum onites L. from the Antalya and Mugla regions and O. vulgare L. from the Kirklareli region of Turkey were extracted with hexane in a Soxhlet apparatus. The oil yields were 14.1–20.0
and 18.5%, respectively. FA compositions of the seed oils were determined by GC and GC/MS. Twenty FA were identified in both
O. onites and O. vulgare seeds. The major FA of both species were linolenic (56.3–57.0%; 61.8%), linoleic (21.5–21.7%; 18.8%), oleic (8.7–8.9%; 5.9%),
palmitic (5.9–6.5%; 5.5%), stearic (2.1–2.4%; 2.1%), and (Z)-11-octadecenoic (0.6–0.8%; 0.5%), respectively. 相似文献
27.
Ibrahim Gunes Adem Cicek Kubilay Aslantas Fuat Kara 《Transactions of the Indian Institute of Metals》2014,67(6):909-917
In this study, the effects of deep cryogenic treatment (DCT) on the wear resistance of AISI 52100 bearing steel were investigated. For this purpose, a number of bearing steel samples were held for different times (12, 24, 36, 48, 60 h) at deep cryogenic temperatures (?145 °C). The wear experiments were carried out in a ball–disk arrangement, by applying loads of 10 and 20 N and a sliding velocity of 0.15 m/s. After conducting the experimental studies, 36 h was found to be the optimal holding time. At this holding time, the wear rate and friction coefficient were decreased, while the hardness reached to maximum values. It was observed that DCT led to significant microstructural changes, which resulted in improved tribological properties. 相似文献
28.
Hirokazu Ozaki Atsushi Kara Zixue Cheng 《Quality and Reliability Engineering International》2011,27(7):895-903
In this paper, we investigate service‐level assurance in high‐availability multi‐unit systems using the M‐for‐N backup scheme. M‐for‐N shared protection (backup) systems with priority control (i.e. prioritized protection switching and prioritized re‐housing of repaired units) can be applied to actual telecommunication devices that are subject to service‐level agreement (SLA) involving reliability measures. A priority level is assigned to each end user in such a system and the switching and unit re‐housing process is subject to the priority. The main contribution of this paper is to give a practical computation method of the user‐perceived availability under the priority control. Our case studies for real telecommunication systems reveal the effect of priority control on the user‐perceived availability. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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