keyword
MENU ▼
Read by QxMD icon Read
search

tofms

keyword
https://www.readbyqxmd.com/read/27930839/expanding-the-klebsiella-pneumoniae-volatile-metabolome-using-advanced-analytical-instrumentation-for-the-detection-of-novel-metabolites
#1
Christiaan A Rees, Flavio A Franchina, Katherine V Nordick, Paul J Kim, Jane E Hill
AIMS: The purpose of this study was to identify the volatile molecules produced by the pathogenic Gram-negative bacterium Klebsiella pneumoniae (ATCC 13883) during in vitro growth using comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC-TOFMS). METHODS AND RESULTS: K. pneumoniae ATCC 13883 was incubated in lysogeny broth (LB) to mid-exponential and stationary growth phases. Headspace volatile molecules from culture supernatants were concentrated using solid-phase microextraction (SPME) and analyzed via GC×GC-TOFMS...
December 8, 2016: Journal of Applied Microbiology
https://www.readbyqxmd.com/read/27914609/determination-of-diamondoids-in-crude-oils-using-gas-purge-microsyringe-extraction-with-comprehensive-two-dimensional-gas-chromatography-time-of-flight-mass-spectrometry
#2
Wanfeng Zhang, Shukui Zhu, Liling Pang, Xuanbo Gao, Gang-Tian Zhu, Donghao Li
Based on a homemade device, gas purge microsyringe extraction (GP-MSE) of crude oil samples was developed for the first time. As a simple, fast, low-cost, sensitive and solvent-saving technique, GP-MSE provides some outstanding advantages over the widely used sample preparation methods for crude oils such as column chromatography (ASTM D2549). Several parameters affecting extraction efficiency were optimized, including extraction temperature, extraction time, extraction solvent, condensing temperature and purge gas flow rate...
November 27, 2016: Journal of Chromatography. A
https://www.readbyqxmd.com/read/27912967/qualitative-analysis-of-copaifera-oleoresin-using-comprehensive-two-dimensional-gas-chromatography-and-gas-chromatography-with-classical-and-cold-electron-ionisation-mass-spectrometry
#3
Yong Foo Wong, Thais M Uekane, Claudia M Rezende, Humberto R Bizzo, Philip J Marriott
Improved separation of both sesquiterpenes and diterpenic acids in Copaifera multijuga Hayne oleoresin, is demonstrated by using comprehensive two-dimensional gas chromatography (GC×GC) coupled to accurate mass time-of-flight mass spectrometry (accTOFMS). GC×GC separation employs polar phases (including ionic liquid phases) as the first dimension ((1)D) column, combined with a lower polarity (2)D phase. Elution temperatures (Te) of diterpenic acids (in methyl ester form, DAME) increased as the (1)D McReynolds' polarity value of the column phase decreased...
November 22, 2016: Journal of Chromatography. A
https://www.readbyqxmd.com/read/27900858/rapid-identification-of-triphenylmethane-dyes-by-ion-mobility-time-of-flight-mass-spectrometry
#4
Alexey A Sysoev, Sergey S Poteshin, Denis M Chernyshev, Alexander A Sysoev
An ion mobility time-of-flight mass spectrometry (IM-TOFMS)-based method has been preliminarily investigated for the identification of triphenylmethane ballpoint pen dyes on paper. The dyes were sampled from one-year-old ballpoint pen ink entries. The entries were written on paper documents stored in the dark in a bookcase. Sample solutions were prepared by extraction of dyes in a vial. Basic violet 2, Methyl violet 6B, Methyl violet 2B and Crystal violet were characterized by IM-TOFMS. Since the ballpoint ink dyes contain ionic compounds, the studied compounds were expected to form stable peaks in the atmospheric pressure drift tube ion mobility spectrometry, and this was experimentally verified...
2016: European Journal of Mass Spectrometry
https://www.readbyqxmd.com/read/27869104/comparative-analysis-of-the-volatile-metabolomes-of-pseudomonas-aeruginosa-clinical-isolates
#5
Heather D Bean, Christiaan A Rees, Jane E Hill
Pseudomonas aeruginosa is a nearly ubiquitous Gram-negative organism, well known to occupy a multitude of environmental niches and cause human infections at a variety of bodily sites, due to its metabolic flexibility, secondary to extensive genetic heterogeneity at the species level. Because of its dynamic metabolism and clinical importance, we sought to perform a comparative analysis on the volatile metabolome (the 'volatilome') produced by P. aeruginosa clinical isolates. In this study, we analyzed the headspace volatile molecules of 24 P...
November 21, 2016: Journal of Breath Research
https://www.readbyqxmd.com/read/27855313/characterization-of-the-clostridium-difficile-volatile-metabolome-using-comprehensive-two-dimensional-gas-chromatography-time-of-flight-mass-spectrometry
#6
Christiaan A Rees, Aimee Shen, Jane E Hill
Clostridium difficile is a bacterial pathogen capable of causing life-threatening infections of the gastrointestinal tract characterized by severe diarrhea. Exposure to certain classes of antibiotics, advanced age, and prolonged hospitalizations are known risk factors for infection by this organism. Anecdotally, healthcare providers have reported that they can smell C. difficile infections in their patients, and several studies have suggested that there may indeed be an olfactory signal associated with C. difficile-associated diarrhea...
November 9, 2016: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
https://www.readbyqxmd.com/read/27812583/the-modulatory-effect-of-infusions-of-green-tea-oolong-tea-and-black-tea-on-gut-microbiota-in-high-fat-induced-obese-mice
#7
Zhibin Liu, Zhichao Chen, Hongwen Guo, Dongping He, Huiru Zhao, Zhiyao Wang, Wen Zhang, Lan Liao, Chen Zhang, Li Ni
Tea consumption has been identified to have an anti-obesity effect. Whether it is associated with gut microbiota modulation is investigated in this study. Phenolic profiles of infusions of green tea, oolong tea and black tea were comprehensively compared first, by utilizing ultra-performance liquid chromatography-electrospray ionization-quadrupole time-of-flight mass spectrometry (UPLC-ESI-Q-TOFMS). Subsequently, high-fat-diet induced obese C57BL/6J mice were orally administered these three types of tea infusions for 13 weeks to evaluate their anti-obesity and gut microbiota modulatory effects...
November 4, 2016: Food & Function
https://www.readbyqxmd.com/read/27788432/hydrothermal-liquefaction-of-cyanidioschyzon-merolae-and-the-influence-of-catalysts-on-products
#8
Tapaswy Muppaneni, Harvind K Reddy, Thinesh Selvaratnam, Kodanda Phani Raj Dandamudi, Barry Dungan, Nagamany Nirmalakhandan, Tanner Schaub, F Omar Holguin, Wayne Voorhies, Peter Lammers, Shuguang Deng
This work investigates the hydrothermal liquefaction (HTL) of Cyanidioschyzon merolae algal species under various reaction temperatures and catalysts. Liquefaction of microalgae was performed with 10% solid loading for 30min at temperatures of 180-300°C to study the influences of two base and two acid catalysts on HTL product fractions. Maximum biocrude oil yield of 16.98% was obtained at 300°C with no catalyst. The biocrude oil yield increased to 22.67% when KOH was introduced into the reaction mixture as a catalyst...
January 2017: Bioresource Technology
https://www.readbyqxmd.com/read/27769467/online-monitoring-of-trace-chlorinated-benzenes-in-flue-gas-of-municipal-solid-waste-incinerator-by-windowless-vuv-lamp-single-photon-ionization-tofms-coupled-with-automatic-enrichment-system
#9
Wei Liu, Jichun Jiang, Keyong Hou, Weiguo Wang, Yachen Qi, Yan Wang, Yuanyuan Xie, Lei Hua, Haiyang Li
Chlorinated benzenes are typical precursors and indicators for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) emissions from waste incinerators. Online and real-time monitoring of chlorobenzenes is a challenge due to their low concentration and complex nature of the flue gas. In this work, a continuous online monitoring system was built for detection of trace chlorinated benzenes based on a time-of-flight mass spectrometer (TOFMS). A single photon ionization (SPI) source based on a radiofrequency-excited windowless vacuum ultraviolet (VUV) lamp was developed for the first time to eliminate the signal attenuation resulting from the contamination of magnesium fluoride windows and to avoid the fragment ions...
December 1, 2016: Talanta
https://www.readbyqxmd.com/read/27769464/high-temperature-diaphragm-valve-based-comprehensive-two-dimensional-gas-chromatography-with-time-of-flight-mass-spectrometry
#10
Chris E Freye, Robert E Synovec
A high temperature diaphragm valve-based two-dimensional (2D) gas chromatography (GC×GC) with time-of-flight mass spectrometry (TOFMS) instrument, with the valve mounted directly in the GC oven, is demonstrated with separations up to 325°C. Use of the diaphragm valve allowed for the use of uncoupled carrier gas flows for (1)D (first column dimension) and (2)D (second column dimension), with a (1)D flow rate of 1ml/min, and a (2)D flow rate 3ml/min. The 3ml/min flow rate on (2)D was selected to ensure compatibility with most TOFMS detectors...
December 1, 2016: Talanta
https://www.readbyqxmd.com/read/27744102/a-metabolomics-investigation-of-the-function-of-the-esx-1-gene-cluster-in-mycobacteria
#11
Du Toit Loots, Conrad C Swanepoel, Mae Newton-Foot, Nicolaas C Gey van Pittius
The ESX-1 gene cluster, encoding the Type-VII secretion (T7S) system and its virulence associated proteins, ESAT-6 and CFP-10, is thought to be responsible for the transport of extracellular proteins across the hydrophobic and highly impermeable, cell envelope of Mycobacterium, and is involved in virulence in Mycobacterium tuberculosis, the causative agent of tuberculosis. Using a GCxGC-TOFMS metabolomics approach, a M. smegmatis ESX-1 knock-out strain (ΔESX-1ms) was compared to that of the M. smegmatis wild-type parent strain, and the metabolite markers due to the presence or absence of the ESX-1 gene cluster were identified...
October 12, 2016: Microbial Pathogenesis
https://www.readbyqxmd.com/read/27693157/short-and-medium-chain-chlorinated-paraffins-in-sediments-from-the-middle-reaches-of-the-yangtze-river-spatial-distributions-source-apportionment-and-risk-assessment
#12
Lin Qiao, Lirong Gao, Dan Xia, Huiting Huang, Minghui Zheng
Chlorinated paraffins (CPs) are easily adsorbed into sediments where they pose potential risks to the ecosystem and human health. Few studies have investigated short- and medium-chain CPs (SCCPs and MCCPs) in sediments. The aim of the present study was to comprehensively investigate contamination levels, spatial distributions, sources and risks posed by CPs in sediments from the middle reaches of the Yangtze River. The sediment samples were analyzed by two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC-TOFMS)...
September 30, 2016: Science of the Total Environment
https://www.readbyqxmd.com/read/27686333/tapping-the-archives-the-sterol-composition-of-marine-sponge-species-as-determined-non-invasively-from-museum-preserved-specimens-reveals-biogeographical-features
#13
S K Lengger, J Fromont, K Grice
Over 8600 species are currently recorded in the phylum Porifera (sponges). They produce a large diversity of biochemical compounds including sterols, with more than 250 different sterols identified. Some of these sterols are of great interest, due to their use for fingerprinting in ecological and biomarker (molecular fossil) studies. As a large number of identified extant species from biodiversity surveys are housed in museum collections, preserved in ethanol, these present a potentially rich source of identified specimens for comparative lipid analyses...
September 29, 2016: Geobiology
https://www.readbyqxmd.com/read/27682410/evaluating-the-translational-temperature-of-molecules-laser-desorbed-after-online-concentration-using-multiphoton-ionization-time-of-flight-mass-spectrometry
#14
Shuhei Miura, Tomohiro Uchimura
We describe a new technique for evaluating the translational temperature of molecules by applying online concentration via analyte adsorption/laser desorption, which is a sample-introduction technique for resonance-enhanced multiphoton ionization time-of-flight mass spectrometry (REMPI-TOFMS). In the present study, analyte molecules were adsorbed via a narrowed capillary tip once, and then the flow of the carrier gas containing the analyte was stopped. After laser desorption, the ion signals induced by REMPI were monitored...
2016: Analytical Sciences: the International Journal of the Japan Society for Analytical Chemistry
https://www.readbyqxmd.com/read/27676126/search-for-plasma-biomarkers-in-drug-free-patients-with-bipolar-disorder-and-schizophrenia-using-metabolome-analysis
#15
Yuki Kageyama, Takaoki Kasahara, Hiromasa Morishita, Nobuko Mataga, Yasuhiko Deguchi, Munehide Tani, Kenji Kuroda, Kotaro Hattori, Sumiko Yoshida, Koki Inoue, Tadafumi Kato
AIM: There is an urgent need for diagnostic biomarkers of bipolar disorder (BD) and schizophrenia (SZ); however, confounding effects of medication hamper biomarker discovery. In this study, we conducted metabolome analyses to identify novel plasma biomarkers in drug-free patients with BD and SZ. METHODS: We comprehensively analyzed plasma metabolites using capillary electrophoresis time-of-flight mass spectrometry in patients with SZ (n = 17), BD (n = 6), and major depressive disorder (n = 9) who had not received psychotropics for at least 2 weeks, and in matched healthy controls (n = 19)...
September 27, 2016: Psychiatry and Clinical Neurosciences
https://www.readbyqxmd.com/read/27666483/human-serum-albumin-hydropersulfide-is-a-potent-reactive-oxygen-species-scavenger-in-oxidative-stress-conditions-such-as-chronic-kidney-disease
#16
Akitomo Shibata, Yu Ishima, Mayumi Ikeda, Hirokazu Sato, Tadashi Imafuku, Victor T G Chuang, Yuya Ouchi, Takaya Abe, Hiroshi Watanabe, Tatsuhiro Ishida, Masaki Otagiri, Toru Maruyama
Recently, hydropersulfide (RSSH) was found to exist in mammalian tissues and fluids. Cysteine hydropersulfide can be found in free cysteine residues as well as in proteins, and it has potent antioxidative activity. Human serum albumin (HSA) is the most abundant protein in mammalian serum. HSA possesses a free thiol group in Cys-34 that could be a site for hydropersulfide formation. HSA hydropersulfide of high purity as a positive control was prepared by treatment of HSA with Na2S. The presence of HSA hydropersulfide was confirmed by spectroscopy and ESI-TOFMS analysis where molecular weights of HSA hydropersulfide by increments of approximately 32 Da (Sulfur atom) were detected...
October 21, 2016: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/27650200/serum-metabolomics-analysis-for-early-detection-of-colorectal-cancer
#17
Kazuhiko Uchiyama, Nobuaki Yagi, Katsura Mizushima, Yasuki Higashimura, Yasuko Hirai, Tetsuya Okayama, Naohisa Yoshida, Kazuhiro Katada, Kazuhiro Kamada, Osamu Handa, Takeshi Ishikawa, Tomohisa Takagi, Hideyuki Konishi, Yoshiaki Kuriu, Masayoshi Nakanishi, Eigo Otsuji, Yoshito Itoh, Yuji Naito
BACKGROUND: Although colorectal cancer (CRC) is one of the most common causes of cancer mortality, early-stage detection improves survival rates dramatically. Because cancer impacts important metabolic pathways, the alteration of metabolite levels as a potential biomarker of early-stage cancer has been the focus of many studies. Here, we used CE-TOFMS, a novel and promising method with small injection volume and high resolution, to separate and detect ionic compounds based on the different migration rates of charged metabolites in order to detect metabolic biomarkers in patients with CRC...
September 20, 2016: Journal of Gastroenterology
https://www.readbyqxmd.com/read/27646461/novel-high-throughput-and-widely-targeted-liquid-chromatography-time-of%C3%A2-flight-mass-spectrometry-method-for-d-amino-acids-in-foods
#18
Yutaka Konya, Moyu Taniguchi, Eiichiro Fukusaki
Recently, the demand for d-amino acid profiling has been drastically increasing because the significance of d-amino acid in various biological events is suggested. However, the present methodologies for d-amino acid profiling are still unsatisfactory. Therefore, a highly sensitive, robust, high-throughput, and user-friendly method for d-amino acid profiling must be developed. In this paper, we developed a novel method for d-amino acid profiling using a combination of a chiral column and time of flight mass spectrometry (TOFMS)...
September 17, 2016: Journal of Bioscience and Bioengineering
https://www.readbyqxmd.com/read/27638539/-metabolome-analysis-of-solid-tumors
#19
J Budczies
Metabolomics, the newest of the omics sciences that also include genomics, transcriptomics and proteomics, has matured into a reliable high-throughput technology. Gas chromatography combined with time-of-flight mass spectrometry (GC-TOFMS) is a suitable method to analyze the central metabolism in fresh frozen tumor tissue samples. Bioinformatics methods, including the PROFILE clustering developed by us, permit integrated analysis and fast interpretation of metabolomics data in the context of enzymatic reactions and metabolic pathways...
November 2016: Der Pathologe
https://www.readbyqxmd.com/read/27574033/high-pressure-photon-ionization-source-for-tofms-and-its-application-for-online-breath-analysis
#20
Yan Wang, Jichun Jiang, Lei Hua, Keyong Hou, Yuanyuan Xie, Ping Chen, Wei Liu, Qingyun Li, Shuang Wang, Haiyang Li
Photon ionization mass spectrometry (PI-MS) is a widely used technique for the online detection of trace substances in complex matrices. In this work, a new high-pressure photon ionization (HPPI) ion source based on a vacuum ultraviolet (VUV) Kr lamp was developed for time-of-flight mass spectrometry (TOFMS). The detection sensitivity was improved by elevating the ion source pressure to about 700 Pa. A radio frequency (RF)-only quadrupole was employed as the ion guide system following the HPPI source to achieve high ion transmission efficiency...
September 20, 2016: Analytical Chemistry
keyword
keyword
109851
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"