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https://www.readbyqxmd.com/read/28738650/determination-of-ascorbic-acid-in-serum-samples-by-screen-printed-carbon-electrodes-modified-with-gold-nanoparticles
#1
M Asunción Alonso-Lomillo, Olga Domínguez-Renedo, Abraham Saldaña-Botín, M Julia Arcos-Martínez
This paper shows the ability of simple modified screen-printed devices for the electrochemical detection of ascorbic acid in different samples, including serum samples. Even if the presence of uric acid does not greatly affect the analysis of ascorbic acid using screen-printed carbon electrodes modified by gold nanoparticles, dopamine must be considered an interferent. Thus, the joint determination of the three compounds has been set out using methods of multivariate calibration. The validated models, built by partial least squares regressions, have been used to determine the concentration of ascorbic acid, dopamine and uric acid of spiked serum samples, with successful results...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738648/matrix-interference-evaluation-employing-gc-and-lc-coupled-to-triple-quadrupole-tandem-mass-spectrometry
#2
S Uclés, A Lozano, A Sosa, P Parrilla Vázquez, A Valverde, A R Fernández-Alba
Gas and liquid chromatography coupled to triple quadrupole tandem mass spectrometry are currently the most powerful tools employed for the routine analysis of pesticide residues in food control laboratories. However, whatever the multiresidue extraction method, there will be a residual matrix effect making it difficult to identify/quantify some specific compounds in certain cases. Two main effects stand out: (i) co-elution with isobaric matrix interferents, which can be a major drawback for unequivocal identification, and therefore false negative detections, and (ii) signal suppression/enhancement, commonly called the "matrix effect", which may cause serious problems including inaccurate quantitation, low analyte detectability and increased method uncertainty...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738647/development-of-an-analytical-methodology-for-obtaining-quantitative-mass-concentrations-from-laap-tof-ms-measurements
#3
Rachel Gemayel, Brice Temime-Roussel, Nathalie Hayeck, Adrien Gandolfo, Stig Hellebust, Sasho Gligorovski, Henri Wortham
Laser ablation aerosol particle-time of flight mass spectrometer (LAAP-ToF-MS) measures the size number of particles, and chemical composition of individual particles in real-time. LAAP-ToF-MS measurements of chemical composition are difficult to quantify, mostly because the instrument sensitivities to various chemical species in the multicomponent atmospheric aerosol particles are unknown. In this study, we investigate a field-based approach for quantitative measurements of ammonium, nitrate, sulfate, OC, and EC, in size-segregated atmospheric aerosols, by LAAP-ToF-MS using concurrent measurements from high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS), and multi-angle absorption photometer (MAAP)...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738640/new-insights-in-forensic-chemistry-nir-chemometrics-analysis-of-toners-for-questioned-documents-examination
#4
Stefano Materazzi, Roberta Risoluti, Sara Pinci, Francesco Saverio Romolo
Near-Infrared spectroscopy (NIRs) coupled to chemometrics was investigated for the first time as a new tool for the analysis of black toners to evaluate its application in forensic cases. Ten black toners from four manufacturers were included in this study and the acquired spectra were compared in order to differentiate toners. Multivariate statistical analysis based on Principal Component Analysis (PCA) was considered to develop a model of comparison of toners in questioned documents. Results demonstrated the capabilities of the approach NIR/Chemometrics to correctly identify toners when printed on different papers and to be not affected by the printing process...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738591/procedures-for-precise-measurements-of-135-cs-137-cs-atom-ratios-in-environmental-samples-at-extreme-dynamic-ranges-and-ultra-trace-levels-by-thermal-ionization-mass-spectrometry
#5
James A Dunne, David A Richards, Hsin-Wei Chen
Determination of (135)Cs/(137)Cs atom ratios has the potential to be a powerful tool for nuclear forensics and monitoring environmental processes. We present optimized chemical separation techniques and thermal ionization mass spectrometry (TIMS) protocols to obtain precise (135)Cs/(137)Cs atom ratios for a range of environmental sample types. We use a combination of double AMP-PAN separation and Sr-spec resin column purification to yield excellent separation from the alkali metals (Rb separation factor > 600), which normally suppress ionization of Cs...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738576/development-of-ph-responsive-polymer-and-citrate-aqueous-two-phase-system-for-extractive-bioconversion-of-cefprozil
#6
Jialing Chen, Zhaoyang Ding, Hongxia Pan, Xuejun Cao
A pH-responsive aqueous two-phase system (pH-ATPS) has been developed by sodium citrate and a recyclable pH-responsive polymer PADB6.8 that can response to the change of pH values. Phase separation mechanism is studied through Low field-NMR. All variables affecting the phase separation are evaluated. Phase characteristics (viscosity, density, interfacial tension) and phase separation kinetic are studied for understanding of separation process and operational parameters in applications. This pH-ATPS has the characters of low interfacial tension, high recovery leading efficient mass transfer and low cost...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738569/optoacoustic-determination-of-analytical-parameters-and-physicochemical-constants-in-highly-concentrated-solutions-of-chromophores
#7
Kristina V Lobko, Mikhail A Shishkin, Tatyana A Filimonova, Dmitry S Volkov, Ivan M Pelivanov, Mikhail A Proskurnin
Determination of chromophores of various classes-rosaniline (fuchsine), cyanidin-3-O-glucoside, tris(1,10-phenanthroline) iron(II), and phenol red - in their concentrated solutions near their solubility limits is performed with the optoacoustic technique for optically dense solutions; light-absorption coefficients of samples range from 0.5 to 500cm(-1). The assessment of these substances in organo-aqueous and organic solvents is possible up to ca. 0.1molL(-1). Characteristic stability and rate constants of the chelation of iron(II) with 1,10-phenanthroline are determined...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738556/development-of-a-new-sample-preparation-method-based-on-liquid-liquid-liquid-extraction-combined-with-dispersive-liquid-liquid-microextraction-and-its-application-on-unfiltered-samples-containing-high-content-of-solids
#8
Mir Ali Farajzadeh, Maryam Abbaspour
A new sample preparation method based on liquid-liquid-liquid extraction combined with dispersive liquid-liquid microextraction followed by gas chromatography-flame ionization detection has been reported for the extraction/preconcentration and determination of trace levels of twelve pesticide residues from different samples with high content of solids without filtration. This method consists of a three-phase system including an aqueous phase (sample solution), acetonitrile, and hexane. The extraction mechanism is based on different affinities of the substances from the sample matrices towards each of the involved phase, which provides a high selectivity to the process...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738551/biomass-saccharification-is-largely-enhanced-by-altering-wall-polymer-features-and-reducing-silicon-accumulation-in-rice-cultivars-harvested-from-nitrogen-fertilizer-supply
#9
Zahoor, Dan Sun, Ying Li, Jing Wang, Yuanyuan Tu, Yanting Wang, Zhen Hu, Shiguang Zhou, Lingqiang Wang, Guosheng Xie, Jianliang Huang, Aftab Alam, Liangcai Peng
In this study, two rice cultivars were collected from experimental fields with seven nitrogen fertilizer treatments. All biomass samples contained significantly increased cellulose contents and reduced silica levels, with variable amounts of hemicellulose and lignin from different nitrogen treatments. Under chemical (NaOH, CaO, H2SO4) and physical (hot water) pretreatments, biomass samples exhibited much enhanced hexoses yields from enzymatic hydrolysis, with high bioethanol production from yeast fermentation...
July 12, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28738539/lncrna-ab073614-regulates-proliferation-and-metastasis-of-colorectal-cancer-cells-via-the-pi3k-akt-signaling-pathway
#10
Yanan Wang, Haoyu Kuang, Jinfang Xue, Liya Liao, Fang Yin, Xiaojun Zhou
The expression profiles of long noncoding RNAs (lncRNAs) in colorectal cancer (CRC) have remained unclear. LncRNA AB073614 is known to be upregulated in ovarian cancer and glioma tissues, and is associated with the occurrence and progression of those cancers. In the present study, we investigated the lncRNA AB073614 gene expression patterns in CRC cell lines and tissue samples from CRC patients, and then analyzed them for possible associations with various clinicopathological characteristics. Furthermore, the roles played by lncRNA AB073614 in CRC cell proliferation, apoptosis, cell cycle progression, migration, and invasion were examined in vitro by using gene knockdown and overexpression techniques...
July 20, 2017: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
https://www.readbyqxmd.com/read/28738528/molecular-basis-for-oxidative-stress-induced-by-simulated-microgravity-in-nematode-caenorhabditis-elegans
#11
Li Zhao, Qi Rui, Dayong Wang
Caenorhabditis elegans is an important in vivo assay system for toxicological studies. Herein, we investigated the role of oxidative stress and the underlying molecular mechanism for induced adverse effects of simulated microgravity. In nematodes, simulated microgravity treatment induced a significant induction of oxidative stress. Genes (mev-1, gas-1, and isp-1) encoding a molecular machinery for the control of oxidative stress were found to be dysregulated in simulated microgravity treated nematodes. Meanwhile, genes (sod-2, sod-3, sod-4, sod-5, aak-2, skn-1, and gst-4) encoding certain antioxidant defense systems were increased in simulated microgravity treated nematodes...
July 19, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28738514/unraveling-the-impact-of-nanoscale-zero-valent-iron-on-the-nitrogen-removal-performance-and-microbial-community-of-anammox-sludge
#12
Zheng-Zhe Zhang, Jia-Jia Xu, Zhi-Jian Shi, Yu-Hui Bai, Ya-Fei Cheng, Hai-Yan Hu, Ren-Cun Jin
Given the increasing use of nanoscale zero-valent iron (NZVI) particles for environmental remediation and wastewater treatment, their potential impact on anaerobic ammonium oxidation (anammox) bacteria was investigated in this study using anammox sludge. Batch assays showed that NZVI concentrations up to 200mgL(-1) did not affect anammox activity, reactive oxygen species production, and cell membrane integrity. The nitrogen removal efficiency of the continuous-flow reactor fluctuated in the presence of 20 or 50mgL(-1) NZVI, but it could return to normal over time, even at 200mgL(-1) NZVI...
July 11, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28738510/degradation-kinetics-and-mechanism-of-sulfadiazine-and-sulfamethoxazole-in-an-agricultural-soil-system-with-manure-application
#13
Yu Zhang, Shuangqing Hu, Hongchang Zhang, Genxiang Shen, Zhejun Yuan, Wei Zhang
Recently, under the application of waste-water, manure and biosolids, antibiotics have been used massively in agriculture resulted in antibiotic resistance and potential environmental risks. In the present study, the removal of sulfadiazine (SDZ) and sulfamethoxazole (SMX) in an agricultural soil system was explored. All the experiments were conducted under different incubation conditions for 49days. The experimental results indicated that all the degradation processes could effectively follow a first-order kinetic model...
July 18, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28738504/prevention-of-melanin-formation-during-aryl-alcohol-oxidase-production-under-growth-limited-conditions-using-an-aspergillus-nidulans-cell-factory
#14
Oscar Pardo-Planas, Rolf A Prade, Michael Müller, Hasan K Atiyeh, Mark R Wilkins
An Aspergillus nidulans cell factory was genetically engineered to produce an aryl alcohol oxidase (AAO). The cell factory initiated production of melanin when growth-limited conditions were established using stationary plates and shaken flasks. This phenomenon was more pronounced when the strain was cultured in a trickle bed reactor (TBR). This study investigated different approaches to reduce melanin formation in fungal mycelia and liquid medium in order to increase the enzyme production yield. Removal of copper from the medium recipe reduced melanin formation in agar cultures and increased enzyme activities by 48% in agitated liquid cultures...
July 8, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28738480/-epidemiological-study-of-sleep-disorder-in-the-elderly
#15
Y Tian, L M Li
As a common health problem in modern society, sleep disorder have a high incidence in the elderly population, which seriously affect the quality of life and physical and mental health of the elderly, and can even aggravate to cause diseases. This review summarizes main research findings in the field of sleep disorder during the past 20 years, describes the sleeping characteristics of elderly, the epidemiological distribution of sleep disorder and possible influencing factors, and finally suggests appropriate measures for the prevention of sleep disorder...
July 10, 2017: Zhonghua Liu Xing Bing Xue za Zhi, Zhonghua Liuxingbingxue Zazhi
https://www.readbyqxmd.com/read/28738476/-relationship-between-risk-factors-of-liver-cancer-and-onset-age-in-ningxia-hui-autonomous-region
#16
Q Liu, B Liu, G R Ding
Objective: To investigate the clinical data of patients with hepatocellular carcinoma in Ningxia Hui Autonomous Region through questionnaire survey, explore the association between the risk factors of liver cancer and the onset age of disease in this area and provide evidence for prevention and treatment of liver diseases. Methods: A retrospectively analysis was conducted in 250 patients with primary hepatocellular carcinoma by using their clinical data collected through questionnaire survey to understand the relationship between gender, smoking, alcohol use, hypertension, diabetes mellitus, hyperlipidemia, family history of liver cancer, liver cirrhosis, HBV infection, eating fish history and other factors and the incidence of hepatocellular carcinoma by univariate and logistic multivariate regression models...
July 10, 2017: Zhonghua Liu Xing Bing Xue za Zhi, Zhonghua Liuxingbingxue Zazhi
https://www.readbyqxmd.com/read/28738472/-effect-of-interleukin-6-and-interleukin-12-on-immune-response-to-hepatitis-b-vaccination-in-infants-of-hbsag-positive-mothers
#17
X F Wang, X H Shi, X X Xu, Z Q Yang, H Y Hao, F Zhang, B Wang, H X Wen, Z D Fu, T Wang, S Y Feng, B Wang, S P Wang
Objective: To explore the effect of interleukin-6 (IL-6) and Interleukin-12 (IL-12) on immune response to hepatitis B vaccination in infants of HBsAg-positive mothers. Methods: A total of 91 neonates whose mothers were HBsAg-positive were included and followed up for 12 months. HBV DNA and HBV serological markers in the peripheral blood of the neonates and infants were detected with fluorescence quantitative polymerase chain reaction (FQ-PCR) and chemiluminescence immunoassay (CLIA), and the levels of IL-6 and IL-12 in the peripheral blood of the neonates and infants were detected with enzyme-linked immunosorbent assay (ELISA)...
July 10, 2017: Zhonghua Liu Xing Bing Xue za Zhi, Zhonghua Liuxingbingxue Zazhi
https://www.readbyqxmd.com/read/28738469/-analysis-on-geographic-distribution-of-high-blood-pressure-prevalence-in-children-and-adolescents-aged-7-18-years-in-china-2014
#18
Y H Dong, Z Y Zou, Z H Wang, S Wang, Z P Yang, Y J Chen, J Ma
Objective: To understand and evaluate the characteristics of geographic distribution of high blood pressure prevalence in children and adolescents aged 7-18 years in China in 2014, and provide evidence for the prevention of hypertension in children and adolescents. Methods: The data of 2014 Chinese National Surveys on Students Constitution and Health conducting 31 provinces (except Hong Kong, Macao and Taiwan) were collected. A total of 216 299 children and adolescents who had complete blood pressure records were selected as study subjects...
July 10, 2017: Zhonghua Liu Xing Bing Xue za Zhi, Zhonghua Liuxingbingxue Zazhi
https://www.readbyqxmd.com/read/28738460/-association-between-sleep-and-leukocyte-telomere-length-in-middle-aged-and-older-adults
#19
H F Liu, F Li, Y H Wang, J H Chen, D X Peng, J Chen, L H Tan, X Mi, B H Zhao
Objective: To understand the association between peripheral leukocytes telomere length (TL) and sleep in middle-aged and old adults. Methods: A total of 176 middle-aged and old adults were investigated by using the Pittsburgh Sleep Quality Index and questionnaire. TL was measured by fluorescence quantitative PCR. The correlation and regression analysis between sleep and telomere length was performed. Results: TL had a mean T/S ratio of 0.995±0.23. There was a negative correlation between TL and age (r=-0.241, P=0...
July 10, 2017: Zhonghua Liu Xing Bing Xue za Zhi, Zhonghua Liuxingbingxue Zazhi
https://www.readbyqxmd.com/read/28738393/estrogen-and-environmental-enrichment-differentially-affect-neurogenesis-dendritic-spine-immunolabeling-and-synaptogenesis-in-the-hippocampus-of-young-and-reproductively-senescent-female-rats
#20
Tina Sager, Michael Kashon, Kristine Krajnak
<br>Background: Studies examining the ability of estrogen replacement therapy (ERT) to enhance memory in women, and in animal models, have not produced consistent results. However, studies examining the effects of activity and exposure to novel environments consistently find enhancement of memory. METHODS: An animal model of reproductive aging was used to determine if estradiol (E2) replacement, activity, and/or exposure to an enriched environment could act synergistically to improve memory, and neural correlates of memory...
July 24, 2017: Neuroendocrinology
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