Matrix solid-phase dispersion (MSPD) isolation and liquid chromatographic determination of oxytetracycline, tetracycline, and chlortetracycline in milk   总被引：3，自引：0，他引：3  

A R Long  L C Hsieh  M S Malbrough  C R Short  S A Barker 《Journal of the Association of Official Analytical Chemists》1990,73(3):379-384

A multiresidue method for the isolation and liquid chromatographic determination of oxytetracycline (OTC), tetracycline (TC), and chlortetracycline (CTC) antibiotics in milk is presented. Blank and tetracycline (OTC, TC, and CTC) fortified milk samples (0.5 mL) were blended with octadecylsilyl (C18, 40 microns, 18% load, endcapped, 2 g) derivatized silica packing material containing 0.05 g each of oxalic acid and disodium ethylenediaminetetraacetic. A column made from the C18/milk matrix was first washed with hexane (8 mL), following which the tetracyclines were eluted with ethyl acetate-acetonitrile (1 + 3; v/v). The eluate contained tetracycline analytes that were free from interfering compounds when analyzed by liquid chromatography with UV detection (photodiode array, 365 nm). Correlation coefficients of standards curves for individual tetracycline isolated from fortified samples were linear (from 0.982 +/- 0.009 to 0.996 +/- 0.004) with average percentage recoveries from 63.5 to 93.3 for the concentration range (100, 200, 400, 800, 1600, and 3200 ng/mL) examined. The inter-assay variability ranged from 8.5 +/- 2.4% to 20.7 +/- 13.0% with an intra-assay variability of 1.0-9.3%.  相似文献   

Multiresidue method for isolation and liquid chromatographic determination of seven benzimidazole anthelmintics in milk     

A R Long  L C Hsieh  M S Malbrough  C R Short  S A Barker 《Journal of the Association of Official Analytical Chemists》1989,72(5):739-741

A multiresidue method for the isolation and liquid chromatographic determination of 7 benzimidazole anthelmintics (thiabendazole, oxfendazole, para-hydroxyfenbendazole, fenbendazole sulfone, mebendazole, albendazole, and fenbendazole) in milk is presented. Blank or benzimidazole-spiked milk samples (0.5 mL) were blended with octadecylsilyl (C-18, 18% load, end-capped) derivatized silica packing material. A column made from the C-18/milk matrix was first washed with hexane (8 mL), and then the benzimidazoles were eluted with methylene chloride-ethyl acetate (1 + 2, v/v; 8 mL). The eluate contained benzimidazole analytes which were free from interfering compounds as determined by UV detection (photodiode array, 290 nm). Correlation coefficients of standard curves for individual benzimidazoles isolated from spiked samples were linear (0.989 +/- 0.003 to 0.998 +/- 0.001) with recoveries ranging from 70 +/- 9% to 107 +/- 2% for the concentration range (62.5-2000 ng/mL) examined. The inter-assay variabilities ranged from 4 +/- 1% to 9 +/- 7% with intra-assay variabilities of 3-6%.  相似文献   

Topographic and biotic regulation of aboveground carbon storage in subtropical broad-leaved forests of Taiwan   总被引：2，自引：0，他引：2  

Ryan W. McEwanYi-Ching Lin  I-Fang SunChang-Fu Hsieh  Sheng-Hsin SuLi-Wan Chang  Guo-Zhang Michael SongHsiang-Hua Wang  Jeen-Lian HwongKuo-Chuan Lin  Kuoh-Cheng YangJyh-Min Chiang 《Forest Ecology and Management》2011,262(9):1817-1825

There is a growing need to understand, and ultimately manage, carbon storage by forest ecosystems. Broad-leaved evergreen forests of Taiwan provide an outstanding opportunity to examine factors that regulate ecosystem carbon storage. We utilized data from three Taiwan Forest Dynamics Plots (FS, LHC, and PTY) in which every tree is identified, measured, tagged and mapped, to examine factors regulating carbon storage as estimated from aboveground biomass. Allometric equations were used to estimate the aboveground biomass of each tree, and a model building procedure was used to examine relationships between plot-level aboveground biomass (AGB; Mg/ha) and a suite of topographic and biotic factors. We found that our study sites have AGB values comparable to some of the most carbon dense forests in the world. Across all three sites, maximum biomass was contained in the taxonomic families Fagaceae, Lauraceae and Theaceae. In the FS site, we identified slope convexity (P = 0.03) and elevation (P < 0.001) as topographic predictors of AGB and found that maximum AGB was found in topographically flat areas. In FS, stem density (P < 0.001) was a significant biotic predictor of AGB and the maxima occurred at intermediate densities. In LHC, we found that convexity (P < 0.001) and slope (P < 0.001) were significantly related to AGB which was maximized along a topographic ridge in the plot. Species richness (P < 0.001) was a significant biotic predictor of AGB in LHC, and the relationship indicated slightly higher AGB at higher levels of species richness. The only significant factor related to AGB in PTY was species richness (P = 0.02). Further work is needed to seek a mechanistic understanding of topographic factors and species richness as drivers of carbon storage in forests.  相似文献   

Response: HIV-2 and Natural Protection Against HIV-1 Infection     

Kanki PJ  Eisen G  Travers KU  Marlink RG  Essex ME  Hsieh CC  Mboup S 《Science (New York, N.Y.)》1996,272(5270):1961-1962

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Using nonwoven fabrics as culture mediums for extensive green roofs: physical properties and cooling effect     

Jia-Hsun Li  Jing-Chzi Hsieh  Ching-Wen Lou  Chien-Teng Hsieh  Yi-Jun Pan  Wen-Hao Hsing  Jia-Horng Lin

《Fibers and Polymers》2016,17(7):1111-1114

Based on the requirements of extensive green roofs, ploylactide (PLA) fibers, cotton fibers, polyester (PET), and low-melting-point LMPET fibers are combined and produced culture mediums for Crassulaceae plants. The resulting mediums are tested for their physical properties and found to be light weight, which is a required condition for plant growth. These features contribute to efficient construction and maintenance. In addition, the optimal cooling effect of the culture mediums is 9.6 °C, which significantly reduces the amount of heat that invades indoor spaces. The decrease in the amount of heat indoors results in a lower demand for air conditioning so as to achieve energy conservation. The results derived from this study help in the promotion of green roofs, thereby slowing down the urban heat island effect and global warming.  相似文献   

Correcting quantum errors with entanglement     

Brun T  Devetak I  Hsieh MH 《Science (New York, N.Y.)》2006,314(5798):436-439

We show how entanglement shared between encoder and decoder can simplify the theory of quantum error correction. The entanglement-assisted quantum codes we describe do not require the dual-containing constraint necessary for standard quantum error-correcting codes, thus allowing us to "quantize" all of classical linear coding theory. In particular, efficient modern classical codes that attain the Shannon capacity can be made into entanglement-assisted quantum codes attaining the hashing bound (closely related to the quantum capacity). For systems without large amounts of shared entanglement, these codes can also be used as catalytic codes, in which a small amount of initial entanglement enables quantum communication.  相似文献   

Different central manifestations in response to electroacupuncture at analgesic and nonanalgesic acupoints in rats: a manganese-enhanced functional magnetic resonance imaging study   总被引：6，自引：0，他引：6       下载免费PDF全文

Jen-Hwey Chiu  Mao-Shu Chung  Hui-Cheng Cheng  Tzu-Cheng Yeh  Jen-Chuen Hsieh  Chung-Yen Chang  Wan-Yo Kuo  Henrich Cheng    Low-Tone Ho 《Canadian journal of veterinary research》2003,67(2):94-101

Acupuncture analgesia is an important issue in veterinary medicine. This study was designed to elucidate central modulation effects in response to electroacupuncture (EA) at different acupoints. Manganese-enhanced functional magnetic resonance imaging was performed in Sprague-Dawley rats after sham acupuncture, sham EA, or true EA at somatic acupoints. The acupoints were divided into 3 groups: group 1, analgesic acupoints commonly used for pain relief, such as Hegu (LI 4); group 2, nonanalgesic acupoints rarely used for analgesic effect, such as Neiguan (PC 6); and group 3, acupoints occasionally used for analgesia, such as Zusanli (ST 36). Image acquisition was performed on a 1.5-T superconductive clinical scanner with a circular polarized extremity coil. The results showed that there was no neural activation caused by EA at a true acupoint with shallow needling and no electric current (sham acupuncture). When EA at a true acupoint was applied with true needling but no electric current (sham EA), there was only a slight increase in brain activity at the hypothalamus; when EA was applied at a true acupoint with true needling and an electric current (true EA), the primary response at the hypothalamus was enhanced. Also, there was a tendency for the early activation of pain-modulation areas to be prominent after EA at analgesic acupoints as compared with nonanalgesic acupoints. In conclusion, understanding the linkage between peripheral acupoint stimulation and central neural pathways provides not only an evidence-based approach for veterinary acupuncture but also a useful guide for clinical applications of acupuncture.  相似文献