keyword
MENU ▼
Read by QxMD icon Read
search

Chromatography

keyword
https://www.readbyqxmd.com/read/29679939/semi-volatile-organic-compounds-in-the-snow-of-russian-arctic-islands-archipelago-novaya-zemlya
#1
A T Lebedev, D M Mazur, O V Polyakova, D S Kosyakov, A Yu Kozhevnikov, T B Latkin, I Andreeva Yu, V B Artaev
Environmental contamination of the Arctic has widely been used as a worldwide pollution marker. Various classes of organic pollutants such as pesticides, personal care products, PAHs, flame retardants, biomass burning markers, and many others emerging contaminants have been regularly detected in Arctic samples. Although numerous papers have been published reporting data from the Canadian, Danish, and Norwegian Arctic regions, the environmental situation in Russian Arctic remains mostly underreported. Snow analysis is known to be used for monitoring air pollution in the regions with cold climate in both short-term and long-term studies...
April 18, 2018: Environmental Pollution
https://www.readbyqxmd.com/read/29679839/xenon-detection-in-human-blood-analytical-validation-by-accuracy-profile-and-identification-of-critical-storage-parameters
#2
Cécile Frampas, Julia Ney, Mark Coburn, Marc Augsburger, Vincent Varlet
Xenon is a rare, mostly inert, noble gas that has applications in a wide range of fields, including medicine. Xenon acts on the human body as a useful organ-protective and anesthetic agent and has also been previously studied for potential applications in fields such as optics, aerospace and medical imaging. Recently, it was discovered that xenon can boost erythropoietin production, and it has been used as a performance-enhancing agent in international sports competitions such as the Sochi Olympic Games. Therefore, screening methods to detect the misuse of xenon by analysis of biological samples and to monitor anesthesia kinetics and efficiency are being investigated...
April 13, 2018: Journal of Forensic and Legal Medicine
https://www.readbyqxmd.com/read/29679786/simultaneous-analysis-of-historical-emerging-and-novel-brominated-flame-retardants-in-food-and-feed-using-a-common-extraction-and-purification-method
#3
Emmanuelle Bichon, Ingrid Guiffard, Anaïs Vénisseau, Elodie Lesquin, Vincent Vaccher, Philippe Marchand, Bruno Le Bizec
Brominated Flame Retardants (BFRs) are still widely used for industrial purposes. These contaminants may enter the food chain where they mainly occur in food of animal origin. The aim of our work was to provide a unique method able to quantify the widest range of BFRs in feed and food items. After freeze-drying and grinding, a pressurized liquid extraction was carried out. The extract was purified on acidified silica, Florisil® and carbon columns, the four separated fractions were analyzed by gas and liquid chromatography coupled to high resolution and tandem mass spectrometry...
April 13, 2018: Chemosphere
https://www.readbyqxmd.com/read/29679754/serum-25-hydroxyvitamin-d-and-breast-cancer-risk-by-pathological-subtype-mcc-spain
#4
Virginia Lope, Adela Castelló, Antonio Mena-Bravo, Pilar Amiano, Nuria Aragonés, Tania Fernández-Villa, Marcela Guevara, Trinidad Dierssen-Sotos, Guillermo Fernandez-Tardón, Gemma Castaño-Vinyals, Rafael Marcos-Gragera, Víctor Moreno, Dolores Salas-Trejo, Marian Diaz-Santos, Madalen Oribe, Isabel Romieu, Manolis Kogevinas, Feliciano Priego-Capote, Beatriz Pérez-Gómez, Marina Pollán
Epidemiologic evidence on the association between vitamin D and breast cancer is still inconclusive. This study analyzes the association between serum 25-hydroxyvitamin D (25(OH)D) and breast cancer risk by pathologic subtype, stage at diagnosis and specific breast cancer risk factors. We conducted a population-based multicase-control study where 546 histologically-confirmed breast cancer cases and 558 population controls, frequently matched by geographic area, age and body mass index, were recruited in 12 Spanish provinces (MCC-Spain)...
April 18, 2018: Journal of Steroid Biochemistry and Molecular Biology
https://www.readbyqxmd.com/read/29679602/solubility-enhanced-gmyl6-fused-with-a-hexa-lysine-tag-promotes-the-cytotoxicity-of-human-nk-cells
#5
Juanjuan Liu, Yuanyuan Jin, Xiaozhou Feng, Sen Zou, Guangxin Lv, Zhifei Zhang, Zhaoyong Yang
Goat myosin light chain 6 (gMYL6) is a constituent of certain extracted immunization-induced goat anti-cancer bioactive peptides (ACBPs). However, little is known about its activity onto NK cells which are the basic cellular attackers in cancer immunotherapy for patients with malignancies. Because of the complicated extraction process and low yield of gMYL6 out of the goat ACBPs' mixture, the Nano-flow liquid chromatography and C-terminal polycationic tag expression strategy were used to identify and enrich the peptide to investigate its bioactivity against cancers/tumors...
April 18, 2018: Immunology Letters
https://www.readbyqxmd.com/read/29679555/mass-spectrometric-measurement-of-urinary-kynurenine-to-tryptophan-ratio-in-children-with-and-without-urinary-tract-infection
#6
Melanie L Yarbrough, Kelleigh E Briden, John V Mitsios, Annette L Weindel, Cindy M Terrill, David A Hunstad, Dennis J Dietzen
BACKGROUND: Indoleamine-2,3-dioxygenase (IDO) catalyzes the first step of tryptophan (Trp) catabolism, yielding kynurenine (Kyn) metabolites. The kynurenine-to-tryptophan (K/T) ratio is used as a surrogate for biological IDO enzyme activity. IDO expression is increased during Escherichia coli urinary tract infection (UTI). Thus, our objective was to develop a method for measurement of Kyn/Trp ratio in human blood and urine and evaluate its use as a biomarker of UTI. METHODS: A mass spectrometric method was developed to measure Trp and Kyn in serum and urine specimens...
April 18, 2018: Clinical Biochemistry
https://www.readbyqxmd.com/read/29679499/quantification-of-metronidazole-in-healthy-subjects-feces-using-a-lc-ms-ms-method
#7
Pravin G Vanol, Mallika Sanyal, Priyanka A Shah, Pranav S Shrivastav
A highly selective and sensitive liquid chromatography-tandem mass spectrometry (LC MS/MS) method is developed for the quantification of metronidazole (MTZ) in human feces. The analyte was recovered from feces after liquid-liquid extraction with ethyl acetate and separated on Waters Symmetry® C18 (100 × 4.6 mm, 5 μm) column using 0.1 % formic acid in water and acetonitrile (40:60, v/v) as the mobile phase. A stable-deuterated internal standard metronidazole-d4 (MTZ-d4) was used in the study. Mass analysis was performed on a triple quadrupole mass spectrometer in the positive electrospray ionization mode...
April 21, 2018: Biomedical Chromatography: BMC
https://www.readbyqxmd.com/read/29679468/high-efficiency-affinity-precipitation-of-multiple-industrial-mabs-and-fc-fusion-proteins-from-cell-culture-harvests-using-z-elp-e2-nanocages
#8
Andrew R Swartz, Xuankuo Xu, Steven J Traylor, Zheng Jian Li, Wilfred Chen
Affinity precipitation using Z-ELP-E2 nanocages has been shown to be a promising alternative to Protein A chromatography for monoclonal antibody (mAb) purification. We have previously described a high-yielding, affinity precipitation process capable of rapidly capturing mAbs from cell culture through spontaneous, multi-valent crosslinking into large aggregates. To challenge the capabilities of this technology, nanocage affinity precipitation was investigated using four industrial mAbs (mAbs A-D) and one Fc fusion protein (Fc A) with diverse molecular properties...
April 21, 2018: Biotechnology and Bioengineering
https://www.readbyqxmd.com/read/29679453/simultaneous-analysis-of-multiple-urinary-biomarkers-for-the-evaluation-of-oxidative-stress-by-automated-on-line-in-tube-solid-phase-microextraction-coupled-with-negative-positive-ion-switching-mode-lc-ms-ms
#9
Akihiro Saito, Mariko Hamano, Hiroyuki Kataoka
This study described an automated on-line method for the simultaneous determination of 8-isoprostane, 8-hydroxy-2'-deoxyguanosine, and 3-nitro-l-tyrosine in human urine. The method involves in-tube solid-phase microextraction using a Carboxen 1006 PLOT capillary column as an extraction device, followed by liquid chromatography with tandem mass spectrometry using a CX column and detection in the negative/positive switching ion-mode by multiple reaction monitoring. Using their stable isotope-labeled internal standards, each of these oxidative stress biomarkers showed good linearity from 0...
April 20, 2018: Journal of Separation Science
https://www.readbyqxmd.com/read/29679387/the-pharmacokinetics-and-pharmacodynamics-of-carfentanil-after-recreational-exposure-a-case-report
#10
Uvaraj Uddayasankar, Colin Lee, Curtis Oleschuk, Gregg Eschun, Robert E Ariano
Carfentanil and related fentanyl analogues have been linked to a number of overdose deaths from drug users in several cities across North America. Diagnosis of carfentanil exposure requires a very high index of clinical suspicion, especially because available laboratory narcotic screens do not detect this agent. We describe a 34-year-old male admitted with depressed level of consciousness and in respiratory failure after recreational exposure to a white powder later inferred to contain carfentanil. Urine and whole blood samples were obtained for conventional preliminary drug screen immunoassays for unknown exposures; in addition to utilizing high pressure liquid chromatography tandem mass spectrometry assay for quantification of carfentanil and its metabolite...
April 20, 2018: Pharmacotherapy
https://www.readbyqxmd.com/read/29679179/isolation-and-characterization-of-phosphofungi-and-screening-of-their-plant-growth-promoting-activities
#11
Xiaohui Wang, Changdong Wang, Junkang Sui, Zhaoyang Liu, Qian Li, Chao Ji, Xin Song, Yurong Hu, Changqian Wang, Rongbo Sa, Jiamiao Zhang, Jianfeng Du, Xunli Liu
Rhizospheric microorganisms can increase phosphorus availability in the soil. In this regard, the ability of phosphofungi to dissolve insoluble phosphorus compounds is greater than that of phosphate-solubilizing bacteria. The aim of the current study was to identify efficient phosphofungi that could be developed as commercial microbial agents. Among several phosphate-solubilizing fungal isolates screened, strain CS-1 showed the highest phosphorus-solubilization ability. Based on phylogenetic analysis of the internal transcribed spacer region sequence, it was identified as Aspergillus niger...
April 20, 2018: AMB Express
https://www.readbyqxmd.com/read/29679156/phthalates-removal-efficiency-in-different-wastewater-treatment-technology-in-the-eastern-cape-south-africa
#12
Taofeek Salaudeen, Omobola Okoh, Foluso Agunbiade, Anthony Okoh
The removal capacity of different wastewater treatment plant (WWTP) technologies adopted in rural areas for phthalate was investigated in the Eastern Cape, South Africa. Wastewater samples collected from three selected WWTPs which use activated sludge (AS), trickling filter (TF), and oxidation pond (OP) technology were extracted using the solid-phase extraction method followed by gas chromatography-mass spectrometry (GC-MS) analysis. The six selected phthalate esters (PAEs) dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), benzyl butyl phthalate (BBP), di(2-ethyl hexyl) phthalate (DEHP), and di-n-octyl phthalate (DOP) were detected in all the samples collected from the WWTPs...
April 20, 2018: Environmental Monitoring and Assessment
https://www.readbyqxmd.com/read/29679131/process-optimization-involving-critical-evaluation-of-oxygen-transfer-oxygen-uptake-and-nitrogen-limitation-for-enhanced-biomass-and-lipid-production-by-oleaginous-yeast-for-biofuel-application
#13
Jayita Chopra, Ramkrishna Sen
Lipid accumulation in oleaginous yeast is generally induced by nitrogen starvation, while oxygen saturation can influence biomass growth. Systematic shake flask studies that help in identifying the right nitrogen source and relate its uptake kinetics to lipid biosynthesis under varying oxygen saturation conditions are very essential for addressing the bioprocessing-related issues, which are envisaged to occur in the fermenter scale production. In the present study, lipid bioaccumulation by P. guilliermondii at varying C:N ratios and oxygen transfer conditions (assessed in terms of kL a) was investigated in shake flasks using a pre-optimized N-source and a two-stage inoculum formulated in a hybrid medium...
April 20, 2018: Bioprocess and Biosystems Engineering
https://www.readbyqxmd.com/read/29679072/polyunsaturated-fatty-acids-metabolism-purine-metabolism-and-inosine-as-potential-independent-diagnostic-biomarkers-for-major-depressive-disorder-in-children-and-adolescents
#14
Xinyu Zhou, Lanxiang Liu, Xinghui Lan, David Cohen, Yuqing Zhang, Arun V Ravindran, Shuai Yuan, Peng Zheng, David Coghill, Lining Yang, Sarah E Hetrick, Xiaofeng Jiang, Jean-Jacques Benoliel, Andrea Cipriani, Peng Xie
Major depressive disorder (MDD) in children and adolescents is a recurrent and disabling condition globally but its pathophysiology remains poorly elucidated and there are limited effective treatments available. We performed metabolic profiling of plasma samples based on ultra-high-performance liquid chromatography equipped with quadrupole time-offlight mass spectrometry to explore the potential biomarkers of depression in children and adolescents with MDD. We identified several perturbed pathways, including fatty acid metabolism-particularly the polyunsaturated fatty acids metabolism, and purine metabolism-that were associated with MDD in these young patients...
April 20, 2018: Molecular Psychiatry
https://www.readbyqxmd.com/read/29679041/a-new-protein-tyrosine-phosphatase-1b-inhibitory-%C3%AE-pyrone-type-polyketide-from-okinawan-plant-associated-aspergillus-sp-tmpu1623
#15
Hiroyuki Yamazaki, Kenta Takahashi, Natsuki Iwakura, Tatsuki Abe, Masanari Akaishi, Satomi Chiba, Michio Namikoshi, Ryuji Uchida
A new polyenyl-α-pyrone polyketide, aspopyrone A (1), was isolated from a culture broth of Okinawan plant-associated Aspergillus sp. TMPU1623 by solvent extraction, ODS column chromatography, and preparative HPLC (ODS). The structure of 1 was assigned based on NMR experiments. Compound 1 exhibited protein tyrosine phosphatase (PTP) 1B and T-cell PTP (TCPTP) inhibitory activities with IC50 values of 6.7 and 6.0 μM, respectively.
April 20, 2018: Journal of Antibiotics
https://www.readbyqxmd.com/read/29678775/involvement-of-gap-junctions-in-astrocyte-impairment-induced-by-manganese-exposure
#16
Cailing Lu, Zhijuan Meng, Yiyuan He, Deqiang Xiao, Haiqing Cai, Yilu Xu, Xianghong Liu, Xinhang Wang, Laiming Mo, Ziwei Liang, Xuejing Wei, Qingqing Ao, Boying Liang, Xiyi Li, Shen Tang, Songchao Guo
Glutamate excitotoxicity, characterized as excessive glutamate stress, is considered to be involved in cerebral ischaemia, brain trauma, and neurodegenerative diseases such as Parkinson's disease and Alzheimer's disease. Glutamate homeostasis disruption was highlighted in Mn neurotoxicity caused by high levels of Mn. Astrocytes, accounting for approximately 50% of the neuronal cells in the central nervous system and maintain glutamate homeostasis, are sensitive to neurotoxicity induced by Mn exposure. Astrocytes are tightly coupled with gap junctions (GJ), which are comprised of connexins, mainly connexin43 (Cx43)...
April 17, 2018: Brain Research Bulletin
https://www.readbyqxmd.com/read/29678574/a-novel-1-acyl-sn-glycerol-3-phosphate-o-acyltransferase-homolog-for-the-synthesis-of-membrane-phospholipids-with-a-branched-chain-fatty-acyl-group-in-shewanella-livingstonensis-ac10
#17
Yosuke Toyotake, Hyun-Nam Cho, Jun Kawamoto, Tatsuo Kurihara
1-Acyl-sn-glycerol-3-phosphate O-acyltransferase (PlsC) plays an essential role in the formation of phosphatidic acid, a precursor of various membrane phospholipids (PLs), in bacteria by catalyzing the introduction of an acyl group into the sn-2 position of lysophosphatidic acid. Various bacteria produce more than one PlsC. However, the physiological significance of the occurrence of multiple PlsCs is poorly understood. A psychrotrophic bacterium, Shewanella livingstonensis Ac10, which produces eicosapentaenoic acid at low temperatures, has five putative PlsCs (PlsC1-5)...
April 17, 2018: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/29678408/a-versatile-polar-embedded-polyphenyl-phase-for-multimodal-separation-in-liquid-chromatography
#18
Yujie Zhang, Qiaoqi Li, Benlin Dai, Shouyong Zhou, Mingliang Zhang, Haifeng Han, Hongdeng Qiu
A new polar-embedded aromatic stationary phase has been prepared by covalently attaching p-biphenylacetamide silane to silica spheres. The retention behavior of this phase was compared with an alkylamide counterpart and octadecyl phases using different classes of analytes, including geometric isomers and congeners from Standard Reference Materials 869b, 870 and 1647e, positional isomers of electron-deficient benzenes, as well as alkylbenzenes and alkylbiphenyls. The relationship between shape selectivity and surface chemistry of stationary phase was comparatively studied...
April 14, 2018: Journal of Chromatography. A
https://www.readbyqxmd.com/read/29678407/determination-of-nine-bisphenols-in-sewage-and-sludge-using-dummy-molecularly-imprinted-solid-phase-extraction-coupled-with-liquid-chromatography-tandem-mass-spectrometry
#19
Xiaoli Sun, Junyu Peng, Muhua Wang, Jincheng Wang, Chunlan Tang, Luoxing Yang, Hua Lei, Fang Li, Xueli Wang, Jiping Chen
This paper describes the determination of bisphenol A (BPA), bisphenol S (BPS), bisphenol F (BPF), bisphenol E (BPE), bisphenol B (BPB), bisphenol AF (BPAF), bisphenol AP (BPAP), bisphenol Z (BPZ) and tetrabromobisphenol A (TBBPA) in sewage and sludge samples. A highly class-selective dummy molecularly imprinted polymer was used for solid phase extraction (SPE) and clean-up of the samples. Bisphenols was quantified by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The developed method had acceptable recoveries (43...
April 3, 2018: Journal of Chromatography. A
https://www.readbyqxmd.com/read/29678260/ganciclovir
#20
Abdullah A Al-Badr, Tariq D S Ajarim
Ganciclovir is synthetic nucleoside analog of guanine closely related to acyclovir but has greater activity against cytomegalovirus. This comprehensive profile on ganciclovir starts with a description of the drug: nomenclature, formulae, chemical structure, elemental composition, and appearance. The uses and application of the drug are explained. The methods that were used for the preparation of ganciclovir are described and their respective schemes are outlined. The methods which were used for the physical characterization of the dug are: ionization constant, solubility, X-ray powder diffraction pattern, crystal structure, melting point, and differential scanning calorimetry...
2018: Profiles of Drug Substances, Excipients, and related Methodology
keyword
keyword
29345
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"