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https://www.readbyqxmd.com/read/29149737/source-apportionment-of-black-carbon-during-winter-in-beijing
#1
Yue Liu, Caiqing Yan, Mei Zheng
Black carbon (BC) in PM2.5 was measured at an urban site in Beijing during winter 2015 using an aethalometer. The characteristics and sources of BC during pollution episodes and clean days were analyzed. The average hourly mass concentration of BC during the study period was 5.31±6.27μg/m(3). BC was highly correlated with PM2.5 (R(2)=0.80), with its concentration ranging from 0.17μg/m(3) in clean days to 35.33μg/m(3) in haze days. Source apportionment results showed that the average contribution of liquid fuel source (e...
November 14, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/29149736/graphene-oxide-reinforced-ionic-liquid-functionalized-adsorbent-for-solid-phase-extraction-of-phenolic-acids
#2
Xiudan Hou, Xiaofeng Lu, Sheng Tang, Licheng Wang, Yong Guo
An environmental friendly sorbent of polymeric ionic liquids modified graphene oxide-grafted silica (PILs@GO@Sil) was synthesized for solid-phase extraction (SPE) of phenolic acids. The sorbent was prepared via a chemical layer-to-layer fabrication including amidation reaction, surface radical chain-transfer polymerization and in situ anion exchange. After modification with PILs, the silica surface had higher positive potential so that it would exhibit stronger electrostatic interaction for acidic compounds compared with GO@Sil...
November 12, 2017: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
https://www.readbyqxmd.com/read/29149735/carbamazepine-lamotrigine-levetiracetam-and-valproic-acid-in-dried-blood-spots-with-liquid-chromatography-tandem-mass-spectrometry-method-development-and-validation
#3
Camilla Linder, Anna Hansson, Sara Sadek, Lars L Gustafsson, Anton Pohanka
Monitoring of antiepileptic drugs in children with epilepsy require multiple visits at a clinic for blood collection. Dried blood spot sampling is an alternative way of collection, performed at home by self-collection and can save time and costs for patients and family members. The aim was to develop and validate an LC-MS/MS dried blood spot method for carbamazepine, lamotrigine, levetiracetam and valproic acid with the requirements of using standard equipment and material in a routine laboratory setting. Whatman-903 filter paper was utilized, and discs were punched into a 96 well plate with an automated puncher and barcode reading...
November 4, 2017: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
https://www.readbyqxmd.com/read/29149712/detection-of-perfluoroalkyl-acids-and-sulphonates-in-italian-eel-samples-by-hplc-hrms-orbitrap
#4
Luca Maria Chiesa, Maria Nobile, Elisa Pasquale, Claudia Balzaretti, Petra Cagnardi, Doriana Tedesco, Sara Panseri, Francesco Arioli
Perfluoroalkyl substances (PFASs) contain one or more carbon-bound hydrogens substituted by fluorine. Since the 1950s, these compounds have been used to manufacture fat- and water-resistant fabrics, paper and food containers, and to produce photographic films, firefighting foams, detergents and insecticides. The widespread use and global distribution of PFASs, have led to their accumulation in the environment. Food, particularly fish and other seafood, is considered the main route of human exposure to PFASs...
October 27, 2017: Chemosphere
https://www.readbyqxmd.com/read/29149711/enantiomeric-characterization-of-herbicide-lactofen-enantioseparation-absolute-configuration-assignment-and-enantioselective-activity-and-toxicity
#5
Jingqian Xie, Lu Zhao, Kai Liu, Fangjie Guo, Zunwei Chen, Weiping Liu
Chiral herbicides consist of two or more enantiomers, which usually differ in their biological properties and behave enantioselectively in biochemical process. Scant studies have been published in the past decades to characterize the enantiomers of herbicide lactofen. In this study, a laboratory method was developed to prepare the lactofen enantiomers using normal phase high performance liquid chromatography with an AD-H column, and μg level production yield was achieved in a single run. The two separated enantiomers had purity of ≫99%, with their absolute configurations assigned by experimental and calculated electronic and vibrational circular dichroism...
October 31, 2017: Chemosphere
https://www.readbyqxmd.com/read/29149702/an-hplc-tandem-mass-spectrometry-for-quantification-of-et-26-hcl-and-its-major-metabolite-in-plasma-and-application-to-a-pharmacokinetic-study-in-rats
#6
Xu Chen, Wensheng Zhang, Sandy Rios, Miriam B Morkos, Xiaoli Ye, Gen Li, Xuehua Jiang, Zhijun Wang, Ling Wang
ET-26-HCl is a new analog of etomidate, a short-acting anesthetic drug, with less adrenal cortex inhibition. The pharmacokinetics of ET-26-HCl in rats needs to be determined for future clinical trials in human subjects. In order to facilitate the pharmacokinetic study, a liquid chromatography based tandem mass spectrometric (HPLC-MS/MS) method was developed and validated for quantification of ET-26-HCl and its major metabolite, ET-26-acid. These two compounds and gabapentin (internal standard) were extracted using a protein precipitation method with methanol and detected by Multiple Reaction Monitoring of m/z transition of 275...
November 8, 2017: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/29149685/simultaneous-drug-identification-in-urine-of-sexual-assault-victims-by-using-liquid-chromatography-tandem-mass-spectrometry
#7
Hei Hwa Lee, Suen Chi Chen, Jong Feng Lee, Hsin Yu Lin, Bai Hsiun Chen
According to domestic and international epidemiological investigation, the proportion of substance involved sexual assault has the trend of ascent. In the past, laboratory methods that investigated urine sample of the sexual assault victims was to screen with enzyme immunoassay and then confirmed with mass spectrometry. The objective of the study is to simultaneously identify abused drugs in 126 decoded urine samples of sexual assault victims by liquid chromatography tandem mass spectrometry. The instrument was operated in multiple-reaction monitoring with an electro-spray positive ionization mode...
November 11, 2017: Forensic Science International
https://www.readbyqxmd.com/read/29149670/an-updated-review-on-tritium-in-the-environment
#8
REVIEW
Frédérique Eyrolle, Loïc Ducros, Séverine Le Dizès, Karine Beaugelin-Seiller, Sabine Charmasson, Patrick Boyer, Catherine Cossonnet
Various studies indicated more or less recently that organically bound tritium (OBT) formed from gaseous or liquid tritium releases into the environment potentially accumulates in organisms contradicting hypotheses associated to methods used to assess the biological impact of tritium on humans (ASN, 2010). Increasing research works were then performed during the last decade in order to gain knowledge on this radionuclide expected to be increasingly released by nuclear installations in the near future within the environment...
November 14, 2017: Journal of Environmental Radioactivity
https://www.readbyqxmd.com/read/29149559/core-shell-microstructure-induced-synergistic-effect-for-efficient-water-droplet-formation-and-cloud-seeding-application
#9
Yanlong Tai, Haoran Liang, Nabil El Hadri, Ali M Abshaev, Buzgigit M Huchinaev, Steve Griffiths, Mustapha Jouiad, Linda Zou
Cloud-seeding materials as a promising water-augmentation technology have drawn more attention recently. We designed and synthesized a novel type of core/shell NaCl/TiO2 (CSNT) particles with controlled particle size, which successfully adsorbed more water vapor (~ 295 times at low relative humidity, 20 % RH) than that of pure NaCl, deliquesced at lower environmental RH of 62 - 66 % than the hygroscopic point (hg.p., 75 % RH) of NaCl, and formed larger water droplets ~ 6 - 10 times of its original measured size area, whereas the pure NaCl still remained as crystal at the same condition...
November 17, 2017: ACS Nano
https://www.readbyqxmd.com/read/29149556/evaluating-force-field-london-dispersion-coefficients-using-the-exchange-hole-dipole-moment-model
#10
Mohamad Mohebifar, Erin R Johnson, Christopher N Rowley
London dispersion interactions play an integral role in materials science and biophysics. Force fields for atomistic molecular simulations typically represent dispersion interactions by the 12-6 Lennard-Jones potential, using empirically-determined parameters. These parameters are generally underdetermined and there is no straightforward way to test if they are physically realistic. Alternatively, the exchange-hole dipole moment (XDM) model from density-functional theory predicts atomic and molecular London dispersion coefficients from first principles, providing an innovative strategy to validate the dispersion terms of molecular-mechanical force fields...
November 17, 2017: Journal of Chemical Theory and Computation
https://www.readbyqxmd.com/read/29149487/fabrication-of-chelate-setting-%C3%AE-tricalcium-phosphate-cement-using-sodium-citrate-and-sodium-alginate-as-mixing-solution-and-its-in-vivo-osteoconductivity
#11
Toshiisa Konishi, Poon Nian Lim, Michiyo Honda, Masaki Nagaya, Hiroshi Nagashima, Eng San Thian, Mamoru Aizawa
Moldable and injectable calcium-phosphate cements (CPCs) are material candidates for bone replacement applications. In the present study, we examined the effectiveness of sodium alginate and sodium citrate additives to the liquid phase of CPC, in improving its handling property as well as mechanical strength. The use of these additives enhanced the handling property significantly, in terms of consistency as compared to CPC without additives due to the liquefying effect caused by the adsorption of citrate ions on the cement particles...
November 17, 2017: Journal of Biomedical Materials Research. Part B, Applied Biomaterials
https://www.readbyqxmd.com/read/29149484/comparative-analysis-of-proteomes-between-diabetic-and-normal-human-sperm-insights-into-the-effects-of-diabetes-on-male-reproduction-based-on-the-regulation-of-mitochondria-related-proteins
#12
Tian An, Yue-Fen Wang, Jia-Xian Liu, Yan-Yun Pan, Yu-Fei Liu, Zhong-Chen He, Fang-Fang Mo, Jun Li, Li-Hua Kang, Yu-Jie Gu, Bo-Han Lv, Si-Huan Gao, Guang-Jian Jiang
This study sought to identify sources of the reduced fertility of men with type 2 diabetes mellitus. Significant reductions in semen volume, sperm concentration, and total sperm count were observed in diabetic individuals, while transmission electron microscopy revealed that the structure of mitochondria in the tail of sperm from diabetic patients was damaged. Proteins potentially associated with these sperm defects were identified using proteomics. Isobaric tagging for relative and absolute quantitation labeling and high-performance liquid chromatography-tandem mass spectrometry allowed us to identify 357 proteins significantly differentially expressed in diabetic versus control semen (>1...
November 17, 2017: Molecular Reproduction and Development
https://www.readbyqxmd.com/read/29149465/controlled-sol-gel-transitions-of-a-thermoresponsive-polymer-in-a-photoswitchable-azobenzene-ionic-liquid-as-a-molecular-machine
#13
Masayoshi Watanabe, Caihong Wang, Kei Hashimoto, Ryota Tamate, Hisashi Kokubo
Producing ionic liquids (ILs) that function as molecular machines for macroscopic change is a challenging issue. We report that photoisomerization of an azobenzene IL at the molecular level could evoke a macroscopic response (light-controlled mechanical sol-gel transitions) for ABA triblock copolymer solutions. The A endblocks, poly(2-phenylethyl methacrylate), show a low critical solution temperature in the IL mixture containing azobenzene while the B midblock, poly(methyl methacrylate), is compatible with the mixture...
November 17, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/29149344/application-of-droplet-detectors-to-alpha-radiation-detection
#14
T Morlat, A C Fernandes, M Felizardo, A Kling, T A Girard, J G Marques, F P Carvalho
Superheated droplet detectors (SDDs) are traditionally employed in the detection of neutrons. In this work the focus is on the detection of alpha particles using C2ClF5 as the target liquid. The alpha-droplet interaction is examined via computational studies, and a geometric model developed to describe the expected detector response. Experiments with alpha-emitting uranium- and samarium-doped SDDs at temperatures of 5-12°C confirm that the event rate is related to the size of the droplets, and are in model agreement for temperatures below 8°C; above this temperature, the acoustic sensitivity is reduced by signal attenuation as a result of the increasing bubble population, for which the addition of an attenuation coefficient restores the agreement with experiment...
November 15, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/29149232/stabilized-electrically-induced-helfrich-deformation-and-enhanced-color-tuning-in-cholesteric-liquid-crystals
#15
Meina Yu, Huai Yang, Deng-Ke Yang
When subjected to an AC electric field perpendicular to its layers, the cholesteric planar state may undergo a periodic layer undulation, known as the Helfrich deformation, which generates a color change of the reflected light. The Helfrich deformation of regular cholesteric liquid crystals is, however, unstable and easily taken over by the focal conic state, and thus the color tuning range is narrow. We demonstrated that the Helfrich deformation can be stabilized in a large electric field region by doping a bent dimer with an anomalously small bend elastic constant and dispersing a small amount of polymer network...
November 17, 2017: Soft Matter
https://www.readbyqxmd.com/read/29149155/lower-cutoffs-for-lc-ms-ms-urine-drug-testing-indicates-better-patient-compliance
#16
Kevin Krock, Amadeo Pesce, Dennis Ritz, Richard Thomas, Agnes Cua, Ryan Rogers, Phil Lipnick, Kristen Kilbourn
BACKGROUND: Urine drug testing is used by health care providers to determine a patient's compliance to their prescribed regimen and to detect non-prescribed medications and illicit drugs. However, the cutoff levels used by clinical labs are often arbitrarily set and may not reflect the urine drug concentrations of compliant patients. OBJECTIVES: Our aim was to test the hypothesis that commonly used cutoffs for many prescribed and illicit drugs were set too high, and methods using these cutoffs may yield a considerable number of false-negative results...
November 2017: Pain Physician
https://www.readbyqxmd.com/read/29149068/a-new-uplc-ms-ms-method-for-the-characterization-and-discrimination-of-polysaccharides-from-genus-ephedra-based-on-enzymatic-digestions
#17
Yong-Gang Xia, Tian-Long Wang, Li-Ming Sun, Jun Liang, Bing-You Yang, Hai-Xue Kuang
Ephedra sinica polysaccharides have been reported to possess important activities, so quality evaluation of polysaccharides from the genus Ephedra is urgent. In this study, enzymatic digestions were performed to establish multiple saccharide fingerprints by ultra-performance liquid chromatography with electrospray ionization triple quadrupole linear ion trap mass spectrometry (UPLC-ESI-TQ-MS/MS) based on a multiple-reaction monitoring in negative mode. Under optimum UPLC-ESI⁻-TQ-MS/MS conditions, excellent separation and quantification of 21 constituents were achieved within 20 min on a solid core column with a 1...
November 17, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/29148895/characterization-of-cefotaxime-and-ciprofloxacin-resistant-commensal-escherichia-coli-originating-from-belgian-farm-animals-indicates-high-antibiotic-resistance-transfer-rates
#18
Ellen Lambrecht, Eva Van Meervenne, Nico Boon, Tom Van de Wiele, Pierre Wattiau, Lieve Herman, Marc Heyndrickx, Els Van Coillie
Food-producing animals represent one of the sources of antibiotic resistant commensal bacteria. There is an increasing awareness that these bacteria might have the potential to transfer their resistance genes to other (pathogenic) bacteria. In this study, 50 commensal Escherichia coli strains originating from food-producing animals and resistant to the "highest priority, critically important antibiotics" cefotaxime and/or ciprofloxacin, were selected for further characterization. For each strain (i) an antibiogram, (ii) the phylogenetic group, (iii) plasmid replicon type, (iv) presence and identification of integrons, and (v) antibiotic resistance transfer ratios were determined...
November 17, 2017: Microbial Drug Resistance: MDR: Mechanisms, Epidemiology, and Disease
https://www.readbyqxmd.com/read/29148812/behavior-of-a-liquid-bridge-between-nonparallel-hydrophobic-surfaces
#19
Mohammadmehdi Ataei, Huanchen Chen, Alidad Amirfazli
When a liquid bridge is formed between two nonparallel identical surfaces, it can move along the surfaces. Literature indicates that the direction of bridge movement is governed by the wettability of surfaces. When the surfaces are hydrophilic, the motion of the bridge is always towards the cusp (intersection of the plane of the two bounding surfaces). While, the movement is hitherto thought to be always pointing away from the cusp, when the surfaces are hydrophobic. In this study, through experiments, numerical simulations, and analytical reasoning, we demonstrate that for hydrophobic surfaces, wettability is not the only factor determining the direction of the motion...
November 17, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/29148805/near-infrared-quantum-dot-emission-enhanced-by-stabilized-self-assembled-j-aggregate-antennas
#20
Francesca S Freyria, José M Cordero, Justin R Caram, Sandra Doria, Amro Dodin, Yue Chen, Adam P Willard, Moungi G Bawendi
Enhancing photoluminescent emission (PL) in the near-infrared-infrared (NIR-IR) spectral region has broad applications from solar energy conversion to biological imaging. We show that self-assembled molecular dye J-aggregates (light-harvesting nanotubes, LHNs) can increase the PL emission of NIR PbS quantum dots (QDs) in both liquid and solid media more than 8-fold, promoted primarily by a long-range antenna effect and efficient Förster resonance energy transfer (FRET) from donor to acceptor. To create this composite material and preserve the optical properties of the nanocrystals, we performed an in situ ligand substitution followed by a functionalization reaction using click-chemistry...
November 17, 2017: Nano Letters
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