http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2013 , Hindawi Publishing Corporation . All rights reserved. Mon, 20 May 2013 16:19:41 +0000 http://www.hindawi.com/journals/jamc/2013/261648/ Water-soluble fluorescent Ag nanoclusters (NCs) were synthesized at room temperature with sodium dodecyl sulfonate (SDS) as a protective agent. The effects of synthetic conditions on the fluorescence properties of Ag NCs were investigated. The results show that the fluorescence intensity of Ag NCs strongly depends on the synthetic conditions, such as the molar ratio of AgNO3 versus SDS and sodium borohydride (NaBH4), the reaction time, and the pH value of the reaction solution. Under the optimum conditions, the as-prepared Ag NCs exist in face-centered-cubic phase with an average size of 2 nm. Fluorescence spectra of Ag NCs show emission peaks at 365 nm for different excitation wavelength. Resonant absorptions are observed at 203 nm and 277 nm in the absorption spectrum, which can be used to establish the electronic levels in the Ag NCs system. Chengzhi Zheng, Huiping Wang, Lingzhi Liu, Manjun Zhang, Jiangong Liang, and Heyou Han Copyright © 2013 Chengzhi Zheng et al. All rights reserved. Thu, 16 May 2013 14:26:39 +0000 http://www.hindawi.com/journals/jamc/2013/256956/ Fei Qi, Guang-Guo Ying, Kaimin Shih, Jolanta Kumirska, Elif Pehlivanoglu-Mantas, and Xiaojun Luo Copyright © 2013 Fei Qi et al. All rights reserved. Tue, 14 May 2013 18:03:01 +0000 http://www.hindawi.com/journals/jamc/2013/318961/ To identify the compounds absorbed in rat serum after the oral administration of Wu-Jia Sheng-Hua (WJSH) capsule, a traditional Chinese medicine (TCM) compound prescription, an ultraperformance liquid chromatography coupled with electrospray ionization mass spectrometry (UPLC/ESI-MS) method, was established. The chromatographic separation of the absorbed compounds and metabolites was achieved with an ACQUITY UPLC BEH C18 column (2.1 mm 50 mm, 1.7 m) under a gradient elution. The mobile phase was composed of acetonitrile and water buffered with ammonium acetate (10 mM) and formic acid (0.1%, V/V). Twelve absorbed compounds and four metabolites were found. Seven of the absorbed compounds were identified by ESI-MS. The identification of absorbed compounds might be helpful for the better understanding of the mechanisms underlying the pharmacological effects of WJSH capsule. Fang Geng, Fashan Wang, Taobo Zou, Kuiyuan Zhu, Wei Ma, Guanghui Tan, and Ning Zhang Copyright © 2013 Fang Geng et al. All rights reserved. Thu, 09 May 2013 14:58:56 +0000 http://www.hindawi.com/journals/jamc/2013/617243/ Persistently increasing incident of cancer in human beings has served to emphasize the importance of studies on mechanism of antitumor substances. Chlorogenic acid (CA), extracted from folium cortex eucommiae, has been confirmed to have lots of biological activities encompassing inhibition of tumor. However, the anticancer mechanism of CA remains unclear. Here, we have utilized a whole mouse genome oligo microarray (4*44K) to analyze gene expression level of female BALB/c mice (implanted with EMT-6 sarcoma cells) after treatment with low, medium, and high-dose CA (5 mg/kg, 10 mg/kg, and 20 mg/kg), docetaxel, interferon, and normal saline separately at 6 time points (3rd, 6th, 9th, 12th, 15th, and 18th days after administration). Differentially expressed genes screened out by time-series analysis, GO analysis, and pathway analysis, and four immune-related genes were selected for further confirmation using RT-qPCR. The results demonstrated that CA is able to change gene expression and that the responsive genes (CaN, NFATC2, NFATC2ip, and NFATC3) involved in immune pathways had been significantly upregulated by CA. Expression of immune factors such as IL-2R and IFN-γ can be improved by CA to promote activation and proliferation of T cells, macrophages, and NK cells, thus enhancing their surveillance and killing abilities, further suppressing the growth rate of tumor cells. Tian Yi Kang, Hua Rong Yang, Jie Zhang, Dan Li, Jie Lin, Li Wang, and XiaoPing Xu Copyright © 2013 Tian Yi Kang et al. All rights reserved. Wed, 08 May 2013 17:53:06 +0000 http://www.hindawi.com/journals/jamc/2013/827361/ A simple and efficient HPLC-DAD (225 nm) method was developed and validated for the simultaneous determination of limonin and six key alkaloids (evodiamine, rutaecarpine, 1-methyl-2-undecyl-4(1H)-quinolone, evocarpine, 1-methy-2-[(6Z,9Z)]-6,9-pentadecadienyl-4-(1H)-quinolone, and dihydroevocarpine) in Evodia rutaecarpa (Juss.) Benth, which has been widely used as one of the Traditional Chinese Medicines. The chromatographic separation was carried out on a Hypersil BDS C18 column, and gradient elution was employed with a mobile phase containing acetonitrile and water. Contents of the analytes in 18 batches of samples were analyzed by ultrasonic extraction with ethanol and water mixture (80 : 20, v/v) followed by HPLC analysis. Separation of the seven analytes was achieved within 60 min with good linearity (). The RSD of both the intraday and interday precision was below 1.85%. The accuracy at different concentrations was within the range of 97.91 to 100.49%. Hierarchical clustering analysis was performed to differentiate and classify the samples based on the contents of the seven constituents. This study indicated that the quality control of E. rutaecarpa could be simplified to the measurement of four constituents, and that limonin, 1-methyl-2-undecyl-4(1H)-quinolone, and dihydroevocarpine should also be served as the chemical markers together with evodiamine for the quality control of Evodia rutaecarpa (Juss.) Benth. Pei-ting Zhang, Bi-yan Pan, Qiong-feng Liao, Mei-cun Yao, Xin-jun Xu, Jin-zhi Wan, Dan Liu, and Zhi-yong Xie Copyright © 2013 Pei-ting Zhang et al. All rights reserved. Wed, 10 Apr 2013 15:40:21 +0000 http://www.hindawi.com/journals/jamc/2013/479056/ Ergosterol from many medicinal fungi has been demonstrated to possess a variety of pharmacological activities in vivo and in vitro. A new method based on cloud-point extraction has been developed, optimized and validated for the determination of ergosterol in rat plasma, urine and faeces by liquid chromatography. The non-ionic surfactant Triton X-114 was chosen as the extract solvent. The chromatographic separation was performed on an Inertsil ODS-3 analytical column with a mobile phase consisting of methanol and water (98 : 2, v/v) at a flow rate of 1 mL/min. The methodology was validated completely. The results indicated good performance in terms of specificity, linearity, detection and quantification limits, precision and accuracy. The method was successfully applied to the pharmacokinetic studies of ergosterol in rats. The results indicate that the ergosterol levels in feces are much higher than those in plasma and urine of the rat. Dan-Qian Chen, Jun-Min An, Ya-Long Feng, Ting Tian, Xiang-Yang Qin, and Ying-Yong Zhao Copyright © 2013 Dan-Qian Chen et al. All rights reserved. Thu, 04 Apr 2013 09:07:19 +0000 http://www.hindawi.com/journals/jamc/2013/389390/ The antitumor activity of roscovitine was tested in four cervical carcinoma cells: C33A, HCE-1, HeLa, and SiHa. The effects of roscovitine on ATP Lite assay, cell cycle, and apoptosis were assessed. The Sub-G1 DNA content occurred great increasing, and this indicates that apoptosis was induced quickly in HeLa cells, but slowly in the other cells. The morphological observation results showed that roscovitine induced apoptosis and cell death in the cervical carcinoma cells. Results revealed that roscovitine exhibited selective cytotoxicity towards 4 cervical carcinoma cells, and the cells showed different morphologic and apoptotic changes at the same concentration. It was estimated that cervical carcinoma cells responded differently to roscovitine because of differences in apoptotic and genetic background in different cervical carcinoma cells. This study suggested that roscovitine had the potential to be a chemotherapeutic agent against cervical carcinoma. Chunying Cui, Yaonan Wang, Yuji Wang, Ming Zhao, and Shiqi Peng Copyright © 2013 Chunying Cui et al. All rights reserved. Thu, 04 Apr 2013 08:10:35 +0000 http://www.hindawi.com/journals/jamc/2013/193230/ A virtual instrumentation (VI) system called VI localized corrosion image analyzer (LCIA) based on LabVIEW 2010 was developed allowing rapid automatic and subjective error-free determination of the pits number on large sized corroded specimens. The VI LCIA controls synchronously the digital microscope image taking and its analysis, finally resulting in a map file containing the coordinates of the detected probable pits containing zones on the investigated specimen. The pits area, traverse length, and density are also determined by the VI using binary large objects (blobs) analysis. The resulting map file can be used further by a scanning vibrating electrode technique (SVET) system for rapid (one pass) “true/false” SVET check of the probable zones only passing through the pit’s centers avoiding thus the entire specimen scan. A complete SVET scan over the already proved “true” zones could determine the corrosion rate in any of the zones. Rogelio Ramos, Roumen Zlatev, Benjamin Valdez, Margarita Stoytcheva, Mónica Carrillo, and Juan-Francisco García Copyright © 2013 Rogelio Ramos et al. All rights reserved. Sun, 31 Mar 2013 18:02:24 +0000 http://www.hindawi.com/journals/jamc/2013/706723/ The purpose of this study is to investigate the effects of Borneol on the pharmacokinetics of notoginsenoside R1 (NGR1) and the ginsenosides Rg1 (GRg1) and Re (GRe) in Panax notoginseng. Reversed phase high-performance liquid chromatography coupled with electrospray ion trap mass spectrometry was employed to determine the concentrations of the three compounds in rabbit plasma. In comparison with rabbits administrated Panax notoginseng extract alone, animals simultaneously taking Panax notoginseng extract and Borneol exhibited significant differences in pharmacokinetic parameters of NGR1, GRg1, and GRe, such as increasing their bioavailability. Quantities of NGR1, GRg1, and GRe in rabbit tissues were also increased after combining administration of Borneol. In addition, the apparent permeability coefficients () of NGR1, GRg1, and GRe were raised by Borneol significantly in Caco-2 cells. However, no significant changes were observed in the efflux ratio (Er) of NGR1, GRg1 and GRe. These data indicate that Borneol has the properties of enhancing the intestinal absorption, increasing the distribution, and inhibiting the metabolism of NGR1, GRg1, and GRe. The underlying mechanism might be attributed to the loosening of the intercellular tight junction. Shixiang Wang, Weijin Zang, Xinfeng Zhao, Weiyi Feng, Ming Zhao, Xi He, Qinshe Liu, and Xiaohui Zheng Copyright © 2013 Shixiang Wang et al. All rights reserved. Sun, 31 Mar 2013 16:06:35 +0000 http://www.hindawi.com/journals/jamc/2013/121783/ The toxic inert ingredients in pesticide formulations are strictly regulated in many countries. In this paper, a simple and efficient headspace-gas chromatography-mass spectrometry (HSGC-MS) method using fluorobenzene as an internal standard (IS) for rapid simultaneous determination of benzene and toluene in pesticide emulsifiable concentrate (EC) was established. The headspace and GC-MS conditions were investigated and developed. A nonpolar fused silica Rtx-5 capillary column ( i.d. and 0.25 μm film thickness) with temperature programming was used. Under optimized headspace conditions, equilibration temperature of 120°C, equilibration time of 5 min, and sample size of 50 μL, the regression of the peak area ratios of benzene and toluene to IS on the concentrations of analytes fitted a linear relationship well at the concentration levels ranging from 3.2 g/L to 16.0 g/L. Standard additions of benzene and toluene to blank different matrix solutions 1ead to recoveries of 100.1%–109.5% with a relative standard deviation (RSD) of 0.3%–8.1%. The method presented here stands out as simple and easily applicable, which provides a way for the determination of toxic volatile adjuvant in liquid pesticide formulations. Lidong Cao, Hua Jiang, Jing Yang, Li Fan, Fengmin Li, and Qiliang Huang Copyright © 2013 Lidong Cao et al. All rights reserved. Thu, 28 Mar 2013 13:51:50 +0000 http://www.hindawi.com/journals/jamc/2013/439039/ For drug candidates, a plasma protein binding (PPB) more than 90% is more meaningful and deserves further investigation in development. In the study, a high-performance liquid chromatography method employing column containing immobilized human serum albumin (HSA) to screen in vitro PPB of leading compounds was established and successfully applied to tested compounds. Good correlation (a coefficient correlation of 0.96) was attained between the reciprocal values () of experimentally obtained retention time of reference compounds eluted through HSA column and the reported PPB values () with a correlation equation of . The method was successfully applied to six test compounds, and the result was confirmed by the conventional ultrafiltration technique, and both yielded equal results. However, due to the particular protein immobilized to column, the method cannot be applied for all compounds and should be exploited judiciously based on the value of the logarithmic measure of the acid dissociation constant (pKa) as per the requirement. If 1-acid glycoprotein and other plasma proteins could be immobilized like HSA with their actual ratio in plasma to column simultaneously, the result attained using immobilized column may be more accurate, and the method could be applied to more compounds without pKa limitation. Ying-Fei Li, Xiao-Qiong Zhang, Wei-Yu Hu, Zheng Li, Ping-Xia Liu, and Zhen-Qing Zhang Copyright © 2013 Ying-Fei Li et al. All rights reserved. Thu, 28 Mar 2013 13:44:56 +0000 http://www.hindawi.com/journals/jamc/2013/380705/ A rapid headspace single-drop microextraction gas chromatography mass spectrometry (SDME-GC-MS) for the analysis of the volatile compounds in Herba Asari was developed in this study. The extraction solvent, extraction temperature and time, sample amount, and particle size were optimized. A mixed solvent of n-tridecane and butyl acetate (1 : 1) was finally used for the extraction with sample amount of 0.750 g and 100-mesh particle size at 70°C for 15 min. Under the determined conditions, the pound samples of Herba Asari were directly applied for the analysis. The result showed that SDME-GC–MS method was a simple, effective, and inexpensive way to measure the volatile compounds in Herba Asari and could be used for the analysis of volatile compounds in Chinese medicine. Guan-Jie Wang, Li Tian, Yu-Ming Fan, and Mei-Ling Qi Copyright © 2013 Guan-Jie Wang et al. All rights reserved. Wed, 27 Mar 2013 18:42:43 +0000 http://www.hindawi.com/journals/jamc/2013/473649/ Bornyl gallate (BG) is a potential drug candidate synthesized by the reaction of two natural products, gallic acid and borneol. Previous studies have strongly suggested that BG is worthy of further investigation due to antioxidant, antiatherosclerosis activities, and obvious activity of stimulating intersegmental vessel growth in zebrafish. This work was designed to elucidate the metabolic profile of BG through analyzing its metabolites in vitro and in vivo by a chromatographic separation coupled with a mass spectrometry. The metabolites of BG were characterized from the rat liver microsome incubation solution, as well as rat urine and plasma after oral administration. Chromatographic separation was performed on an Agilent TC-C18 column (250 mm × 4.6 mm, 5 μm) with gradient elution using methanol and water containing 0.2% (V : V) formic acid as the mobile phase. Metabolites identification involved analyzing the retention behaviors, changes of molecular weights and MS/MS fragment patterns of BG and the metabolites. Five compounds were identified as isomers of hydroxylated BG metabolites in vitro. The major metabolites of BG in rat urine and plasma proved to be BG-O-glucuronide and O-methyl BG-O-glucuronide. The proposed method confirmed to be a reliable and sensitive alternative for characterizing metabolic pathways of BG. Wei Lan, Liujiao Bian, Xinfeng Zhao, Pu Jia, Xue Meng, Yizhen Wu, Shixiang Wang, Sha Liao, Jie Yu, and Xiaohui Zheng Copyright © 2013 Wei Lan et al. All rights reserved. Sun, 24 Mar 2013 17:40:14 +0000 http://www.hindawi.com/journals/jamc/2013/179627/ A simple, rapid, and selective HPLC-UV method was developed for the determination of antihypertensive drug substances: amlodipine besilat (AML), olmesartan medoxomil (OLM), valsartan (VAL), and hydrochlorothiazide (HCT) in pharmaceuticals and plasma. These substances are mostly used as combinations. The combinations are found in various forms, especially in current pharmaceuticals as threesome components: OLM, AML, and HCT (combination I) and AML, VAL, and HCT (combination II). The separation was achieved by using an RP-CN column, and acetonitrile-methanol-10 mmol orthophosphoric acid pH 2.5 (7 : 13 : 80, v/v/v) was used as a mobile phase; the detector wavelength was set at 235 nm. The linear ranges were found as 0.1–18.5 μg/mL, 0.4–25.6 μg/mL, 0.3–15.5 μg/mL, and 0.3–22 μg/mL for AML, OLM, VAL, and HCT, respectively. In order to check the selectivity of the method for pharmaceutical preparations, forced degradation studies were carried out. According to the validation studies, the developed method was found to be reproducible and accurate as shown by RSD ≤6.1%, 5.7%, 6.9%, and 4.6% and relative mean error (RME) ≤10.6%, 5.8%, 6.5%, and 6.8% for AML, OLM, VAL, and HCT, respectively. Consequently, the method was applied to the analysis of tablets and plasma of the patients using drugs including those substances. Serife Evrim Kepekci Tekkeli Copyright © 2013 Serife Evrim Kepekci Tekkeli. All rights reserved. Tue, 12 Mar 2013 15:29:51 +0000 http://www.hindawi.com/journals/jamc/2013/602091/ Alsterpaullone, a small molecule cyclin-dependent kinase (CDK) inhibitor, regulates the cell cycle progression. Beyond death-inducing properties, we identified the effect of alsterpaullone on cycle procedure and apoptosis of HeLa cell. It was found that alsterpaullone inhibited HeLa cells in a time-dependent (0–72 h) and dose-dependent (0–30 μM) manner. In the presence of alsterpaullone, HeLa cells were arrested in G2/M prior to undergoing apoptosis via a mechanism that is involved in the regulation of various antiapoptotic genes, DNA-repair, transcription, and cell cycle progression. Compared to controls, alsterpaullone effectively prevented HeLa cells from entering S-phase. These potential therapeutic efficacies could be correlated with the activation of caspase-3. Chunying Cui, Yuji Wang, Yaonan Wang, Ming Zhao, and Shiqi Peng Copyright © 2013 Chunying Cui et al. All rights reserved. Tue, 12 Mar 2013 09:32:35 +0000 http://www.hindawi.com/journals/jamc/2013/419349/ The presence of phthalate esters (PAEs) in the environment has gained a considerable attention due to their potential impacts on public health. This study reports the first data on the occurrence of 15 PAEs in the water near the Mopanshan Reservoir—the new and important water source of Harbin city in Northeast China. As drinking water is a major source for human exposure to PAEs, the fate of target PAEs in the two waterworks (Mopanshan Waterworks and Seven Waterworks) was also analyzed. The results demonstrated that the total concentrations of 15 PAEs in the water near the Mopanshan Reservoir were relatively moderate, ranging from 355.8 to 9226.5 ng/L, with the mean value of 2943.1 ng/L. DBP and DEHP dominated the PAE concentrations, which ranged from 52.5 to 4498.2 ng/L and 128.9 to 6570.9 ng/L, respectively. The occurrence and concentrations of these compounds were heavily spatially dependent. Meanwhile, the results on the waterworks samples suggested no significant differences in PAE levels with the input of the raw waters. Without effective and stable removal of PAEs after the conventional drinking water treatment in the waterworks (25.8% to 76.5%), the risks posed by PAEs through drinking water ingestion were still existing, which should be paid special attention to the source control in the Mopanshan Reservoir and some advanced treatment processes for drinking water supplies. Yu Liu, Zhonglin Chen, and Jimin Shen Copyright © 2013 Yu Liu et al. All rights reserved. Wed, 06 Mar 2013 13:36:31 +0000 http://www.hindawi.com/journals/jamc/2013/210653/ In the last years, hormone consumption has increased exponentially. Because of that, hormone compounds are considered emerging pollutants since several studies have determinted their presence in water influents and effluents of wastewater treatment plants (WWTPs). In this study, a quantitative method for the simultaneous determination of oestrogens (estrone, 17β-estradiol, estriol, 17α-ethinylestradiol, and diethylstilbestrol), androgens (testosterone), and progestogens (norgestrel and megestrol acetate) has been developed to determine these compounds in wastewater samples. Due to the very low concentrations of target compounds in the environment, a solid phase extraction procedure has been optimized and developed to extract and preconcentrate the analytes. Determination and quantification were performed by ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The method developed presents satisfactory limits of detection (between 0.15 and 9.35 ng·), good recoveries (between 73 and 90% for the most of compounds), and low relative standard deviations (under 8.4%). Samples from influents and effluents of two wastewater treatment plants of Gran Canaria (Spain) were analyzed using the proposed method, finding several hormones with concentrations ranged from 5 to 300 ng·. Rayco Guedes-Alonso, Zoraida Sosa-Ferrera, and José Juan Santana-Rodríguez Copyright © 2013 Rayco Guedes-Alonso et al. All rights reserved. Thu, 21 Feb 2013 13:23:39 +0000 http://www.hindawi.com/journals/jamc/2013/482316/ A novel horseradish peroxidase- (HPR-) doped magnetic core-shell Fe3O4@SiO2@Au nanocomposites (Fe-Au MNPs) were employed on immunoassay for the determination of C-reactive protein (CRP) based on a electrochemical quartz crystal microbalance detector (EQCM). Firstly, the secondary CRP antibody and HRP were both immobilized on the Fe-Au MNPs (Fe-Au MNPs-anti-CRP2/HRP) as a signal tag. Secondly, the above tag and the primary antibody (anti-CRP1) in the bottom of 96-well microtiter plate were employed to conjugate with a serial of CRP concentrations to produce a sandwich immunocomplex. Thirdly, the immunocomplex solution was subsequently exposed to -diaminobenzidine (DAB) in the presence of H2O2, resulting in an insoluble product. When the precipitation solution was dripped on EQCM, it can achieve a decrease of frequency of crystal (). The amount of was proportional to (CRP) from 0.003 to 200 ng mL−1 with a low detection limit of 1 pg mL−1. Compared with the enzyme-linked immunosorbent assay (ELISA), the immunoassay shows greatly improved sensitivity due to the significant amount of HRP labeled on signal tag. It also has good specificity and low sample consumption, which is expected to be a benefit for the CRP screening in early diagnosis of cardiovascular disease. Ning Gan, Ping Xiong, Ji Wang, Tianhua Li, Futao Hu, Yuting Cao, and Lei Zheng Copyright © 2013 Ning Gan et al. All rights reserved. Sun, 17 Feb 2013 18:52:20 +0000 http://www.hindawi.com/journals/jamc/2013/568614/ Although the treatment technology of sulfamethoxazole has been investigated widely, there are various issues such as the high cost, inefficiency, and secondary pollution which restricted its application. Bioflocculant, as a novel method, is proposed to improve the removal efficiency of PPCPs, which has an advantage over other methods. Bioflocculant MFX, composed by high polymer polysaccharide and protein, is the metabolism product generated and secreted by Klebsiella sp. In this paper, MFX is added to 1 mg/L sulfanilamide aqueous solution substrate, and the removal ratio is evaluated. According to literatures review, for MFX absorption of sulfanilamide, flocculant dosage, coagulant-aid dosage, pH, reaction time, and temperature are considered as influence parameters. The result shows that the optimum condition is 5 mg/L bioflocculant MFX, 0.5 mg/L coagulant aid, initial pH 5, and 1 h reaction time, and the removal efficiency could reach 67.82%. In this condition, MFX could remove 53.27% sulfamethoxazole in domestic wastewater, and the process obeys Freundlich equation. R2 value equals 0.9641. It is inferred that hydrophobic partitioning is an important factor in determining the adsorption capacity of MFX for sulfamethoxazole solutes in water; meanwhile, some chemical reaction probably occurs. Jie Xing, Ji-Xian Yang, Ang Li, Fang Ma, Ke-Xin Liu, Dan Wu, and Wei Wei Copyright © 2013 Jie Xing et al. All rights reserved. Mon, 28 Jan 2013 15:11:31 +0000 http://www.hindawi.com/journals/jamc/2013/387124/ The potential of triethylenetetramine (TETA) to inhibit the oxidation of pyrite in H2SO4 solution had been investigated by using the open-circuit potential (OCP), cyclic voltammetry (CV), potentiodynamic polarization, and electrochemical impedance (EIS), respectively. Experimental results indicate that TETA is an efficient coating agent in preventing the oxidation of pyrite and that the inhibition efficiency is more pronounced with the increase of TETA. The data from potentiodynamic polarization show that the inhibition efficiency () increases from 42.08% to 80.98% with the concentration of TETA increasing from 1% to 5%. These results are consistent with the measurement of EIS (43.09% to 82.55%). The information obtained from potentiodynamic polarization also displays that the TETA is a kind of mixed type inhibitor. Yun Liu, Zhi Dang, Yin Xu, and Tianyuan Xu Copyright © 2013 Yun Liu et al. All rights reserved. Sun, 30 Dec 2012 11:52:44 +0000 http://www.hindawi.com/journals/jamc/2012/415697/ Small organic molecules are challenging targets for an aptamer selection using the SELEX technology (SELEX—Systematic Evolution of Ligans by EXponential enrichment). Often they are not suitable for immobilization on solid surfaces, which is a common procedure in known aptamer selection methods. The Capture-SELEX procedure allows the selection of DNA aptamers for solute targets. A special SELEX library was constructed with the aim to immobilize this library on magnetic beads or other surfaces. For this purpose a docking sequence was incorporated into the random region of the library enabling hybridization to a complementary oligo fixed on magnetic beads. Oligonucleotides of the library which exhibit high affinity to the target and a secondary structure fitting to the target are released from the beads for binding to the target during the aptamer selection process. The oligonucleotides of these binding complexes were amplified, purified, and immobilized via the docking sequence to the magnetic beads as the starting point of the following selection round. Based on this Capture-SELEX procedure, the successful DNA aptamer selection for the aminoglycoside antibiotic kanamycin A as a small molecule target is described. Regina Stoltenburg, Nadia Nikolaus, and Beate Strehlitz Copyright © 2012 Regina Stoltenburg et al. All rights reserved. Mon, 24 Dec 2012 09:02:46 +0000 http://www.hindawi.com/journals/jamc/2012/364013/ A sensitive HPLC method was developed for the quantitative determination of isoliquiritin apioside (ILA) and isoliquiritin (IL) in rat plasma. After protein precipitation with acetonitrile, chloroform was used to separate lipid-soluble impurities from the plasma samples and remove acetonitrile. A chromatography was carried out on Diamonsil C18 ( mm; 5 μm) analytical column, using a mobile phase consisting of water (containing phosphoric acid 0.1%, v/v); acetonitrile (72 : 28, v/v) at a flow rate of 1.0 mL/min. The wavelength-switching technology was performed to determine ILA and IL at 360 nm and wogonoside (internal standard, IS) at 276 nm. The calibration curves of ILA and IL were fairly linear over the concentration ranges of 0.060–3.84 μg/mL () and 0.075–4.80 μg/mL (), respectively. The average extract recoveries of ILA, IL, and IS were all over 80%. The precision and accuracy for all concentrations of quality controls and standards were within 15%. The lower limit of quantification (LLOQ) was 0.060 μg/mL for ILA and 0.075 μg/mL for IL. The method was used in pharmacokinetic study after an oral administration of Zhigancao extract to rats. Yan-yun Yang, Liang Xu, Song-yao Hao, Yan Li, and Zhen-Qiu Zhang Copyright © 2012 Yan-yun Yang et al. All rights reserved. Sun, 16 Dec 2012 13:32:17 +0000 http://www.hindawi.com/journals/jamc/2012/254391/ An amino acid, 3S-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid, was isolated for the first time from the leaves of Cichorium endivia. The complete assignment of its 1H and 13C NMR spectroscopic data was carried out also for the first time based on extensive 1D and 2D NMR experiments. Cytotoxicity of this isolated compound against HCT-8 and HepG2 human cancer cell lines was evaluated for the first time, with moderate activities being found. Fu-Xin Wang, An-Jun Deng, Jin-Feng Wei, Hai-Lin Qin, and Ai-Ping Wang Copyright © 2012 Fu-Xin Wang et al. All rights reserved. Wed, 05 Dec 2012 11:46:40 +0000 http://www.hindawi.com/journals/jamc/2012/308013/ Ki-Hyun Kim, David Parker, Fusheng Li, and Kea-Tiong Tang Copyright © 2012 Ki-Hyun Kim et al. All rights reserved. Thu, 29 Nov 2012 16:18:50 +0000 http://www.hindawi.com/journals/jamc/2012/438701/ A rapid, simple method based on graphite furnace atomic absorption spectrometry is described for the direct determination of arsenic in coal fly ash. Solid samples were directly introduced into the atomizer without preliminary treatment. The direct analysis method was not always free of spectral matrix interference, but the stabilization of arsenic by adding palladium nitrate (chemical modifier) and the optimization of the parameters in the furnace program (temperature, rate of temperature increase, hold time, and argon gas flow) gave good results for the total arsenic determination. The optimal furnace program was determined by analyzing different concentrations of a reference material (NIST1633b), which showed the best linearity for calibration. The optimized parameters for the furnace programs for the ashing and atomization steps were as follows: temperatures of 500–1200 and 2150°C, heating rates of 100 and 500°C s−1, hold times of 90 and 7 s, and medium then maximum and medium argon gas flows, respectively. The calibration plots were linear with a correlation coefficient of 0.9699. This method was validated using arsenic-containing raw coal samples in accordance with the requirements of the mass balance calculation; the distribution rate of As in the fly ashes ranged from 101 to 119%. Sri Hartuti, Shinji Kambara, Akihiro Takeyama, Kazuhiro Kumabe, and Hiroshi Moritomi Copyright © 2012 Sri Hartuti et al. All rights reserved. Tue, 27 Nov 2012 11:16:22 +0000 http://www.hindawi.com/journals/jamc/2012/161865/ A mechanism is proposed for the first step of ionization occurring in matrix-assisted laser desorption ionization, leading to protonated and deprotonated matrix (Ma) molecules ( and ions). It is based on observation that in solid state, for carboxyl-containing MALDI matrices, the molecules form strong hydrogen bonds and their carboxylic groups can act as both donors and acceptors. This behavior leads to stable dimeric structures. The laser irradiation leads to the cleavage of these hydrogen bonds, and theoretical calculations show that both and ions can be formed through a two-photon absorption process. Alternatively, by the absorption of one photon only, a heterodissociation of one of the O–H bonds can lead to a stable structure containing both cationic and anionic sites. This structure could be considered an intermediate that, through the absorption of a further photon, leads to the formation of matrix ions. Some experiments have been performed to evaluate the role of thermal ionization and indicate that its effect is negligible. Some differences have been observed for different matrices in the formation of analyte molecule (M) ion , , , and , and they have been explained in terms of ionization energies, pKa values, and thermodynamic stability. Laura Molin, Roberta Seraglia, Zbigniew Czarnocki, Jan K. Maurin, Franciszek A. Pluciński, and Pietro Traldi Copyright © 2012 Laura Molin et al. All rights reserved. Thu, 22 Nov 2012 08:43:55 +0000 http://www.hindawi.com/journals/jamc/2012/713862/ Cloud point extraction (CPE) has been used for the preconcentration and simultaneous determination of cobalt (Co) and lead (Pb) in fresh and wastewater samples. The extraction of analytes from aqueous samples was performed in the presence of 8-hydroxyquinoline (oxine) as a chelating agent and Triton X-114 as a nonionic surfactant. Experiments were conducted to assess the effect of different chemical variables such as pH, amounts of reagents (oxine and Triton X-114), temperature, incubation time, and sample volume. After phase separation, based on the cloud point, the surfactant-rich phase was diluted with acidic ethanol prior to its analysis by the flame atomic absorption spectrometry (FAAS). The enhancement factors 70 and 50 with detection limits of 0.26 μg L−1 and 0.44 μg L−1 were obtained for Co and Pb, respectively. In order to validate the developed method, a certified reference material (SRM 1643e) was analyzed and the determined values obtained were in a good agreement with the certified values. The proposed method was applied successfully to the determination of Co and Pb in a fresh surface and waste water sample. Naeemullah, Tasneem Gul Kazi, Faheem Shah, Hassan Imran Afridi, Sumaira Khan, Sadaf Sadia Arian, and Kapil Dev Brahman Copyright © 2012 Naeemullah et al. All rights reserved. Sun, 11 Nov 2012 11:59:38 +0000 http://www.hindawi.com/journals/jamc/2012/245415/ A simple and sensitive high performance liquid chromatography-tandem mass spectrometry (HPLC-ESI-MS-MS) method was developed and validated for the quantification of creatinine in human urine. The analysis was carried out on an Agilent Zorbax Eclipse XDB-C18 column ( mm, 3.5 μm). The mobile phase was 0.1% formic acid in water and 0.1% formic acid in acetonitrile (50/50, v/v). Linear calibration curves were obtained in the concentration range of 1–2000.0 ng/mL, with a lower limit of quantification of 0.99 ng/mL. The intra- and interday precision (RSD) values were below 3%. The method was successfully applied to a bioequivalence study of creatinine in Chinese smokers and nonsmokers. The total cotinine in 24 h urine and cotinine : creatinine ratio were also positively associated (Pearson , ). However, cotinine : creatinine ratio varied significantly across smoking groups for the difference of individual. 24 h urinary cotinine was more appropriate for expressing correlation with tar than cotinine : creatinine ratio. Hongwei Hou, Wei Xiong, Xiaotao Zhang, Dongkui Song, Gangling Tang, and Qingyuan Hu Copyright © 2012 Hongwei Hou et al. All rights reserved. Mon, 05 Nov 2012 15:57:47 +0000 http://www.hindawi.com/journals/jamc/2012/659858/ This paper aims to enhance the credibility of applying the sulfur K-edge XANES spectroscopy as an innovative “fingerprint” for characterizing environmental samples. The sensitivities of sulfur K-edge XANES spectra of ten sulfur compound standards detected by two different detectors, namely, Lytle detector (LyD) and Germanium detector (GeD), were studied and compared. Further investigation on “self-absorption” effect revealed that the maximum sensitivities of sulfur K-edge XANES spectra were achieved when diluting sulfur compound standards with boron nitride (BN) at the mixing ratio of 0.1%. The “particle-size” effect on sulfur K-edge XANES spectrum sensitivities was examined by comparing signal-to-noise ratios of total suspended particles (TSP) and particulate matter of less than 10 millionths of a meter collected at three major cities of Thailand. The analytical results have demonstrated that the signal-to-noise ratios of sulfur K-edge XANES spectra were positively correlated with sulfate content in aerosols and negatively connected with particle sizes. The combination of hierarchical cluster analysis (HCA) and principal component analysis (PCA) has proved that sulfur K-edge XANES spectrum can be used to characterize German terrestrial soils and Andaman coastal sediments. In addition, this study highlighted the capability of sulfur K-edge XANES spectra as an innovative “fingerprint” to distinguish tsunami backwash deposits (TBD) from typical marine sediments (TMS). Siwatt Pongpiachan, Kanjana Thumanu, Charnwit Kositanont, Klaus Schwarzer, Jörg Prietzel, Phoosak Hirunyatrakul, and Itthipon Kittikoon Copyright © 2012 Siwatt Pongpiachan et al. All rights reserved. Mon, 10 Sep 2012 13:12:30 +0000 http://www.hindawi.com/journals/jamc/2012/489239/ Reduced sulfur compounds are considered to be important odorants from pig production due to their low odor threshold values and low solubility in slurry. The objective of the present study was to investigate the use of a portable method with a single silica gel column for trapping/separation coupled with chemiluminescence detection (SCTS-CL) for measurement of methanethiol and dimethyl sulfide in sample air from pig production. Proton-transfer-reaction mass spectrometry (PTR-MS) was used to evaluate the trapping/separation. The silica gel column used for the SCTS-CL efficiently collected hydrogen sulfide, methanethiol and dimethyl sulfide. The measurement of methanethiol by SCTS-CL was clearly interfered by the high concentration of hydrogen sulfide found in pig production, and a removal of hydrogen sulfide was necessary to obtain reliable results. Air samples taken from a facility with growing-finishing pigs were analyzed by SCTS-CL, PTR-MS, and a gas chromatograph with sulfur chemiluminescence detection (GC-SCD) to evaluate the SCTS-CL. The difference between the concentrations of methanethiol and dimethyl sulfide measured with SCTS-CL, PTR-MS, and GC-SCD was below 10%. In conclusion, the SCTS-CL is a portable and low-cost alternative to the commercial methods that can be used to measure methanethiol and dimethyl sulfide in sample air from pig production. Michael Jørgen Hansen, Kei Toda, Tomoaki Obata, Anders Peter S. Adamsen, and Anders Feilberg Copyright © 2012 Michael Jørgen Hansen et al. All rights reserved.