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https://www.readbyqxmd.com/read/29333991/evaluation-of-a-portable-gas-chromatograph-with-photoionization-detector-under-variations-of-voc-concentration-temperature-and-relative-humidity
#1
Jhy-Charm Soo, Eun Gyung Lee, Ryan F LeBouf, Michael L Kashon, William Chisholm, Martin Harper
The objective of this present study was to evaluate the performance of a portable gas chromatograph ─ photoionization detector (GC-PID), under various test conditions to determine if it could be used in occupational settings. A mixture of seven volatile organic compounds (VOCs) - acetone, ethylbenzene, methyl isobutyl ketone, toluene, m-xylene, p-xylene, and o-xylene - was selected because its components are commonly present in paint manufacturing industries. A full-factorial combination of four concentration levels (exposure scenarios) of VOC mixtures, three different temperatures (25˚C, 30˚C, and 35˚C), and three relative humidities (RHs; 25%, 50%, and 75%) was conducted in a full- size controlled environmental chamber...
January 15, 2018: Journal of Occupational and Environmental Hygiene
https://www.readbyqxmd.com/read/29331935/disruption-of-thyroid-hormone-sulfotransferase-activity-by-brominated-flame-retardant-chemicals-in-the-human-choriocarcinoma-placenta-cell-line-bewo
#2
Christopher P Leonetti, Craig M Butt, Heather M Stapleton
Brominated flame retardants (BFRs) have been shown to disrupt thyroid hormone (TH) homeostasis through multiple mechanisms, including inhibition of enzymes that regulate intracellular levels of THs, such as sulfotransferases (SULTs). The placenta plays a critical role in helping to maintain TH levels during fetal development and expresses SULTs. This is concerning given that disruption of TH regulation within the placenta could potentially harm the developing fetus. In this study, we investigated the effects of two polybrominated diphenyl ethers (PBDEs), two hydroxylated PBDEs, and 2,4,6-tribromophenol (2,4,6-TBP) on TH SULT activity in a choriocarcinoma placenta cell line (BeWo)...
December 28, 2017: Chemosphere
https://www.readbyqxmd.com/read/29329885/innoscent-system-advancing-flavor-analysis-using-an-original-gas-chromatographic-analytical-device
#3
A Villière, S Le Roy, C Fillonneau, C Prost
Despite continuous advances in analytical and physiological knowledge, the comprehension of an aroma is still a challenge. Gas chromatography coupled to olfactometry (GC-O) is an efficient method to identify and estimate individual potential of odorants, but there is a gap between this individual characterization and the effective contribution of compounds in the mixture, which is due to complex chemical and perceptual interactions. Therefore, recombination and omission experiments are often performed to achieve an understanding of food aromas...
December 24, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/29329212/study-of-the-thermal-properties-and-the-fire-performance-of-flame-retardant-organic-pcm-in-bulk-form
#4
Anabel Palacios, Alvaro De Gracia, Laia Haurie, Luisa F Cabeza, A Inés Fernández, Camila Barreneche
The implementation of organic phase change materials (PCMs) in several applications such as heating and cooling or building comfort is an important target in thermal energy storage (TES). However, one of the major drawbacks of organic PCMs implementation is flammability. The addition of flame retardants to PCMs or shape-stabilized PCMs is one of the approaches to address this problem and improve their final deployment in the building material sector. In this study, the most common organic PCM, Paraffin RT-21, and fatty acids mixtures of capric acid (CA), myristic acid (MA), and palmitic acid (PA) in bulk, were tested to improve their fire reaction...
January 12, 2018: Materials
https://www.readbyqxmd.com/read/29327426/quantification-of-total-cholesterol-in-human-milk-by-gas-chromatography
#5
Maurizio Beggio, Cristina Cruz-Hernandez, Pierre-Alain Golay, Le Ye Lee, Francesca Giuffrida
Human milk provides the key nutrients necessary for infant growth and development. The objective of this study was to develop and validate a method to analyze the cholesterol content in liquid human milk samples along lactation. Direct saponification of the sample using ethanolic potassium hydroxide solution under cold conditions was applied and unsaponifiable matter was separated by centrifugation. Cholesterol was converted into its trimethylsilyl ether and the derivative analyzed by gas chromatography coupled with a flame ionization detector...
January 12, 2018: Journal of Separation Science
https://www.readbyqxmd.com/read/29326315/plasma-n-3-and-n-6-fatty-acids-are-differentially-related-to-carotid-plaque-and-its-progression-mesa-the-multi-ethnic-study-of-atherosclerosis
#6
Brian T Steffen, Weihua Guan, James H Stein, Mathew C Tattersall, Joel D Kaufman, Veit Sandfort, Moyses Szklo, Michael Y Tsai
OBJECTIVE: ω-3 (n-3) fatty acids (FAs) have long been considered healthful dietary components, yet recent clinical trials have questioned their cardiovascular benefits. By contrast, the ω-6 (n-6) FAs have been considered harmful, proatherogenic macronutrients, despite an absence of empirical evidence supporting this hypothesis. We aimed to determine whether plasma n-3 and n-6 FAs are related to risk of carotid plaque and its progression in 3327 participants of the MESA (Multi-Ethnic Study of Atherosclerosis)...
January 11, 2018: Arteriosclerosis, Thrombosis, and Vascular Biology
https://www.readbyqxmd.com/read/29319567/clinical-epidemiology-of-acute-burn-injuries-at-nepal-cleft-and-burn-centre-kathmandu-nepal
#7
Bishal Karki, Shankar Man Rai, Kiran Kishore Nakarmi, Surendra Jung Basnet, Mangal Gharti Magar, Krishna Kumar Nagarkoti, Sunil Thapa
BACKGROUND: Burn injury is a global health problem mainly occurring in developing countries. The Nepal Cleft and Burn Centre at Kirtipur Hospital, Kathmandu, has been providing the acute burn care since 2013 with 7 intensive care unit beds, 30 general beds, and 2 dedicated operating rooms. A similar descriptive study was performed in this center in 2014. These studies will be helpful for developing prevention strategies and monitoring the progress in the standard of care of acute burn patients...
January 9, 2018: Annals of Plastic Surgery
https://www.readbyqxmd.com/read/29319239/cellular-structure-fabricated-on-ni-wire-by-a-simple-and-cost-effective-direct-flame-approach-and-its-application-in-fiber-shaped-supercapacitors
#8
Zhihong Wang, Fenhui Cao, Kongfa Chen, Yingming Yan, Yifu Chen, Yaohui Zhang, Xingbao Zhu, Bo Wei, Yueping Xiong, Zhe Lv
Cellular metals with the large surface-to-volume ratios and excellent electrical conductivity are widely applicable and have thus been studied extensively. It is highly desirable to develop a facile and cost-effective process for fabrication of porous metallic structures, more so for micron/nano pores. Herein, we propose a novel direct-flame strategy for in-situ fabrication of micron cellular architecture on Ni metal precursor. The flame provides required heat, but also serves as a fuel reformer providing a gas mixture of H2, CO and O2 for redox treatment of Ni metals...
January 10, 2018: ChemSusChem
https://www.readbyqxmd.com/read/29316461/impact-of-particle-size-on-distribution-and-human-exposure-of-flame-retardants-in-indoor-dust
#9
Rui-Wen He, Yun-Zi Li, Ping Xiang, Chao Li, Xin-Yi Cui, Lena Q Ma
The effect of dust particle size on the distribution and bioaccessibility of flame retardants (FRs) in indoor dust remains unclear. In this study, we analyzed 20 FRs (including 6 organophosphate flame retardants (OPFRs), 8 polybrominated diphenyl ethers (PBDEs), 4 novel brominated flame retardants (NBFRs), and 2 dechlorane plus (DPs)) in composite dust samples from offices, public microenvironments (PME), and cars in Nanjing, China. Each composite sample (one per microenvironment) was separated into 6 size fractions (F1-F6: 200-2000µm, 150-200µm, 100-150µm, 63-100µm, 43-63µm, and <43µm)...
January 6, 2018: Environmental Research
https://www.readbyqxmd.com/read/29316351/gestational-triphenyl-phosphate-exposure-in-c57bl-6-mice-perturbs-expression-of-insulin-like-growth-factor-signaling-genes-in-maternal-and-fetal-liver
#10
Nicola A Philbrook, Victoria E Restivo, Christine L Belanger, Louise M Winn
Triphenyl phosphate (TPhP) is an organophosphorus flame retardant and plasticizer that has been added to numerous consumer products in recent years. TPhP is not overtly toxic, however recent studies have suggested that it may have metabolic disrupting effects following developmental exposure. The present study aimed to investigate the developmental and potential metabolic effects of TPhP in a murine model. C57Bl/6 dams were exposed on gestational days (GD) 8, 10, 12, and 14 to 0, 5, 25, or 50 mg/kg TPhP via intraperitoneal injection...
January 8, 2018: Birth Defects Research
https://www.readbyqxmd.com/read/29315925/directed-self-assembly-symmetry-breaking-and-electronic-modulation-of-metal-oxide-clusters-by-pyramidal-heteroanions
#11
Haralampos N Miras, Harikleia Sartzi, De-Liang Long, Stephen Sproules, Leroy Cronin
Mixed valence/metal polyoxometalate (POM) clusters are one of the most interesting host species showing the ability to incorporate a wide range of heteroatoms of various charges and geometries. We report herein, the incorporation of different pyramidal EO32- heteroanions (E = PH, S, Se, Te) which are responsible not only for directing the templated assembly of a family of mixed-metal POMs but also for the symmetry-breaking of the traditional Dawson architecture and modulation of the electronic characteristics of the cluster's shell...
January 9, 2018: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29310314/determination-of-silicon-in-biomass-and-products-of-pyrolysis-process-via-high-resolution-continuum-source-atomic-absorption-spectrometry
#12
Flávio V Nakadi, Caroline Prodanov, Wiliam Boschetti, Maria Goreti R Vale, Bernhard Welz, Jailson B de Andrade
Thermochemical processes can convert the biomass into fuels, such as bio-oil. The biomass submitted to pyrolysis process, such as fibers, are generally rich in silicon, an element that can lead to damages in an engine when there is high concentration in a fuel. High-resolution continuum source atomic absorption spectrometry (HR-CS AAS) is an interesting alternative for Si determination in the products and byproducts of the pyrolysis process because, besides the flame (F) and graphite furnace (GF) atomizers, it has enhanced the application of direct analysis of solid samples (SS) within GF...
March 1, 2018: Talanta
https://www.readbyqxmd.com/read/29307059/application-of-magnetic-nanoparticles-coated-with-sodium-dodecyl-sulfate-and-modified-with-2-5-bromo-2-pyridylazo-5-diethyl-aminophenol-as-a-novel-adsorbent-for-dispersive-magnetic-solid-phase-extraction-and-determination-of-palladium-in-soil-samples
#13
Meng Wang, Lan Wu, Qiufen Hu, Yaling Yang
A rapid, sensitive, precise, and accurate dispersive-magnetic solid-phase extraction technique combined with flame atomic absorption spectrometry was established for pre-concentration and separation of Pd (II) in soil samples. In the developed system, 5-amine-1,10-phenanthroline was used as synergistic complexant; sodium dodecyl sulfate and 2-(5-bromo-2-pyridylazo)-5-diethyl aminophenol ligand coated on magnetic nanoparticles were synthesized by a chemical precipitation method, and then employed as the efficient magnetic adsorbent with good magnetic properties and dispersibility...
January 6, 2018: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/29306213/urinary-metabolites-of-organophosphate-esters-in-children-in-south-china-concentrations-profiles-and-estimated-daily-intake
#14
Yi Chen, Jianzhang Fang, Lu Ren, Ruifang Fan, Jianqing Zhang, Guihua Liu, Li Zhou, Dingyan Chen, Yingxin Yu, Shaoyou Lu
Organophosphate esters (OPEs) are widely used in household products as flame retardants or plasticizers and have become ubiquitous pollutants in environmental media. However, little is known about OPE metabolites in humans, especially in children. In this study, eight OPE metabolites were measured in 411 urine samples collected from 6 to 14-year-old children in South China. Bis(2-chloroethyl) phosphate (BCEP), bis(1-chloro-2-propyl) phosphate (BCIPP) and diphenyl phosphate (DPHP) were the dominant OPE metabolites, and their median concentrations were 1...
January 3, 2018: Environmental Pollution
https://www.readbyqxmd.com/read/29306024/organophosphate-triesters-and-selected-metabolites-enhance-binding-of-thyroxine-to-human-transthyretin-in-vitro
#15
Katie L Hill, Timo Hamers, Jorke H Kamstra, William G Willmore, Robert J Letcher
The toxicological properties of organophosphate (OP) triesters that are used as flame retardants and plasticizers are currently not well understood, though increasing evidence suggests they can affect the thyroid system. Perturbation of thyroid hormone (TH) transport is one mechanism of action that may affect thyroid function. The present study applied an in vitro competitive protein binding assay with thyroxine (T4) and human transthyretin (hTTR) to determine the potential for the OP triesters, TDCIPP (tris(1,3-dichloro-2-propyl) phosphate), TBOEP (tris(butoxyethyl) phosphate), TEP (triethyl phosphate), TPHP (triphenyl phosphate), p-OH-TPHP (para-hydroxy triphenyl phosphate), and the OP diester DPHP (diphenyl phosphate), to competitively displace T4 from hTTR...
January 3, 2018: Toxicology Letters
https://www.readbyqxmd.com/read/29304461/legacy-and-emerging-organophosph%C3%AE-rus-flame-retardants-in-car-dust-from-greece-implications-for-human-exposure
#16
Christina Christia, Giulia Poma, Athanasios Besis, Constantini Samara, Adrian Covaci
Organophosphorus flame retardants (PFRs) and emerging PFRs (ePFRs) are two groups of compounds used as replacements for brominated flame retardants (BFRs). They have already been detected in indoor dust (mainly in homes and offices). To date, few studies investigated the occurrence of FRs in car dust and the information of possible health risks is still limited. The present study reports on the investigation of the levels and profiles of eight target PFRs: tris(2-ethylhexyl) phosphate (TEHP), tris(2-chloroethyl) phosphate (TCEP), tris(2-butoxyethyl) phosphate (TBEP), triphenyl phosphate (TPHP), 2-ethylhexyl diphenyl phosphate (EHDPHP), tris(1-chloro-2-propyl) phosphate (TCIPP), tri cresyl phosphate (TCP), tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) and four target ePFRs; 2,2-bis(chloromethyl)propane-1,3-diyltetrakis(2-chloroethyl)bisphosphate (V6), isodecyl diphenyl phosphate (iDDPHP), resorcinol bis(diphenylphosphate) (RDP) and bisphenol A-bis(diphenyl phosphate) (BDP) in car dust from Greece...
December 23, 2017: Chemosphere
https://www.readbyqxmd.com/read/29304458/transformation-of-tetrabromobisphenol-a-by-rhodococcus-jostii-rha1-effects-of-heavy-metals
#17
Shen Xu, Yong-Feng Wang, Liu-Yan Yang, Rong Ji, Ai-Jun Miao
Tetrabromobisphenol A (TBBPA) is one of the most widely used brominated flame retardants in the world but it is also a pollutant of global concern. In the present study, we studied the transformation of 14C-labeled TBBPA by a polychlorinated-biphenyl-degrading bacterium, Rhodococcus jostii RHA1 (RHA1), under oxic conditions. During the 5-day incubation, TBBPA was biotransformed rapidly first to its monomethyl ether MeO-TBBPA and then to its more hydrophobic but less toxic dimethyl ether diMeO-TBBPA. The biotransformation followed pseudo-first-order decay kinetics, with a half-life of TBBPA of 0...
December 28, 2017: Chemosphere
https://www.readbyqxmd.com/read/29303426/methods-for-the-analysis-of-organophosphorus-flame-retardants-comparison-of-gc-ei-ms-gc-nci-ms-lc-esi-ms-ms-and-lc-apci-ms-ms
#18
Masahiro Tokumura, Yuichi Miyake, Qi Wang, Hayato Nakayama, Takashi Amagai, Sayaka Ogo, Kazunari Kume, Takeshi Kobayashi, Shinji Takasu, Kumiko Ogawa
Organophosphorus flame retardants (PFRs) are extensively used as alternatives to banned polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD). In this study, we analyzed 14 PFRs by means of four mass-spectrometry-based methods: gas chromatography combined with electron-impact mass spectrometry (GC-EI-MS) or negative-chemical-ionization mass spectrometry (GC-NCI-MS) and liquid chromatography combined with tandem mass spectrometry using electrospray ionization (LC-ESI-MS/MS) or atmospheric pressure chemical ionization (LC-APCI-MS/MS)...
January 5, 2018: Journal of Environmental Science and Health. Part A, Toxic/hazardous Substances & Environmental Engineering
https://www.readbyqxmd.com/read/29289283/the-presence-and-partitioning-behavior-of-flame-retardants-in-waste-leachate-and-air-particles-from-norwegian-waste-handling-facilities
#19
Nicolas A O Morin, Patrik L Andersson, Sarah E Hale, Hans Peter H Arp
Flame retardants in commercial products eventually make their way into the waste stream. Herein the presence of flame retardants in Norwegian landfills, incineration facilities and recycling sorting/defragmenting facilities is investigated. These facilities handled waste electrical and electronic equipment (WEEE), vehicles, digestate, glass, combustibles, bottom ash and fly ash. The flame retardants considered included polybrominated diphenyl ethers (∑BDE-10) as well as dechlorane plus, polybrominated biphenyls, hexabromobenzene, pentabromotoluene and pentabromoethylbenzene (collectively referred to as ∑FR-7)...
December 2017: Journal of Environmental Sciences (China)
https://www.readbyqxmd.com/read/29289282/oxidation-reactivity-of-1-2-bis-2-4-6-tribromophenoxy-ethane-btbpe-by-compound-i-model-of-cytochrome-p450s
#20
Zhongyu Wang, Zhiqiang Fu, Qi Yu, Jingwen Chen
Alternative brominated flame retardants (BFRs) have become prevalent as a consequence of restrictions on the use of polybrominated diphenyl ethers (PBDEs). For risk assessment of these alternatives, knowledge of their metabolism via cytochrome P450 enzymes is needed. We have previously proved that density functional theory (DFT) is able to predict the metabolism of PBDEs by revealing the molecular mechanisms. In the current study, the reactivity of 1,2-bis(2,4,6-tribromophenoxy)ethane and structurally similar chemicals with the Compound I model representing the active site of P450 enzymes was investigated...
December 2017: Journal of Environmental Sciences (China)
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