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Baree Chilcote, LaTara Rust, Katie D Nizio, Shari L Forbes
At outdoor crime scenes, cadaver-detection and blood-detection dogs may be tasked with locating blood that is days, weeks or months old. Although it is known that the odour profile of blood will change during this time, it is currently unknown how the profile changes when exposed to the environment. Such variables must be studied in order to understand when the odour profile is no longer detectable by the scent-detection dogs and other crime scene tools should be implemented. In this study, blood was deposited onto concrete and varnished wood surfaces and weathered in an outdoor environment over a three-month period...
March 2018: Science & Justice: Journal of the Forensic Science Society
Pavel Kubáček, Lubomír Prokeš, Annapurna Pamreddy, Eladia María Peña-Méndez, José Elias Conde, Milan Alberti, Josef Havel
RATIONALE: Only a few arsenic phosphides are known. High potential for the generation of new compounds is offered by Laser Ablation Synthesis (LAS) and when Laser Desorption Ionisation (LDI) is coupled with simultaneous Time of Flight Mass Spectrometry (TOFMS), immediate identification of the clusters can be achieved. METHODS: LAS was used for the generation of arsenic phosphides via laser ablation of phosphorus-arsenic mixtures while quadrupole ion trap time-of-flight mass spectrometry (QIT-TOFMS) was used to acquire the mass spectra...
March 8, 2018: Rapid Communications in Mass Spectrometry: RCM
Farshid Mashayekhy Rad, Caroline Leck, Leopold L Ilag, Ulrika Nilsson
RATIONALE: Fatty acids are enriched in the ocean surface microlayer (SML) and have as a consequence been detected worldwide in sea spray aerosols. In searching for a relationship between the properties of the atmospheric aerosol and its ability to form cloud condensation nuclei and to promote cloud droplet formation over remote marine areas, the role of surface active fatty acids sourced from the SML is of interest to be investigated. Here is presented a fast method for profiling of major fatty acids in SML samples collected in the high Arctic (89 °N, 1 °W) in the summer of 2001...
March 9, 2018: Rapid Communications in Mass Spectrometry: RCM
Zhibin Yin, Le Hang, Rong Liu, Wei Hang, Benli Huang
A newly constructed laser desorption (532 nm, 5 ns) and laser postionization (266 nm, 5 ns) time-of-flight mass spectrometer (LD-LPI-TOFMS) has been applied for improving the detection sensitivity of elements in solid samples. This method affords to acquire the information of the elemental impurities in solid standards as well as limit of detection (LOD) down to 10-8 g/g for some elements. Neutral atoms of solids are generated by low-irradiance laser desorption (< 108 W/cm2 ), followed by high-irradiance laser postionization (~ 109 W/cm2 ) of the desorbed atoms, facilitating to decoupling the desorption and ionization processes in spatial and temporal domain...
March 5, 2018: Journal of Mass Spectrometry: JMS
Wenli Wang, Xi Feng, Danni Zhang, Bei Li, Baoguo Sun, Hongyu Tian, Yuan Liu
A microwave assisted extraction method coupled with solvent assisted flavor evaporation (MAE-SAFE) was used to extract the volatiles from three-selected Chinese dry-cured hams (Jinhua ham, Xuanwei ham and Rugao ham). Extracts were analyzed by comprehensive two-dimensional gas chromatography with high-resolution time-of-flight mass spectrometry (GC × GC/HR-TOFMS), gas chromatography-mass spectrometry (GC-MS), respectively. A total 165 volatile compounds were identified by GC × GC/HR-TOFMS while only 50 compounds were identified by GC-MS...
February 24, 2018: Meat Science
Hiromu Takemura, Shigemi Terakubo, Ninyo Okamura, Hideki Nakashima
In the course of measuring the intracellular antibacterial activity of antibiotics using a human alveolar epithelial cell line A549, we discovered that the antimicrobial activity of several carbapenems (CPs) decreased in the supernatant of the cells cultured with fetal calf serum (FCS)-free RPMI1640 medium (RPMI). Further investigation revealed A549 culture supernatant inhibited the antibacterial activity of CPs but did not inactivate other types of antibiotics. CE-TOFMS and LC-TOFMS metabolomics analysis of the supernatant revealed the presence of l-cysteine (Cys), which is not an original component in RPMI...
February 26, 2018: Journal of Infection and Chemotherapy: Official Journal of the Japan Society of Chemotherapy
Dipayan Chakraborty, Pamir Nag, Dhananjay Nandi
A new time of flight mass spectrometer (TOFMS) has been developed to study the absolute dissociative electron attachment (DEA) cross section using a relative flow technique of a wide variety of molecules in gas phase, ranging from simple diatomic to complex biomolecules. Unlike the Wiley-McLaren type TOFMS, here the total ion collection condition has been achieved without compromising the mass resolution by introducing a field free drift region after the lensing arrangement. The field free interaction region is provided for low energy electron molecule collision studies...
February 2018: Review of Scientific Instruments
Hajime Abe, Daisuke Hashikawa, Takaya Minami, Kohei Ohtani, Kentaro Masuda, Shinya Matsumoto, Masahiko Inouye
Coordination cages were composed by self-organization of rigid C3v-symmetric heptaarene tridentates and Pd(II) precursors. The heptaarene framework involves one mesitylene, three phenol, and three pyridine moieties which were connected by Suzuki coupling reactions. The treatment of the tridentates with Pd(dppp)(OTf)2 or Pd(en)(NO3)2 in a 2:3 molar ratio furnished coordination cages, which was ascertained by crystallography, 1H NMR and DOSY measurements, and ESI-TOFMS and UV-vis spectra. The cages have six phenolic hydroxy groups inside and were expected to incorporate hydrogen-bonding guest molecules such as saccharides...
February 23, 2018: Journal of Organic Chemistry
Lina Mörén, Richard Perryman, Tim Crook, Julia K Langer, Kevin Oneill, Nelofer Syed, Henrik Antti
BACKGROUND: Tumour cells have a high demand for arginine. However, a subset of glioblastomas has a defect in the arginine biosynthetic pathway due to epigenetic silencing of the rate limiting enzyme argininosuccinate synthetase (ASS1). These tumours are auxotrophic for arginine and susceptible to the arginine degrading enzyme, pegylated arginine deiminase (ADI-PEG20). Moreover, ASS1 deficient GBM have a worse prognosis compared to ASS1 positive tumours. Since altered tumour metabolism is one of the hallmarks of cancer we were interested to determine if these two subtypes exhibited different metabolic profiles that could allow for their non-invasive detection as well as unveil additional novel therapeutic opportunities...
February 8, 2018: BMC Cancer
Yan Wang, Lei Hua, Jichun Jiang, Yuanyuan Xie, Keyong Hou, Qingyun Li, Chenxin Wu, Haiyang Li
Small molecule metabolites are widely used as biomarkers in the research field of metabolomics for disease diagnosis and exposure assessment. As a readily available biofluid containing plenty of volatile organic metabolites (VOMs), urine is ideal for non-invasive metabolomic analysis; however, there is still lack of rapid analysis method for VOMs in urine. Here we report a kind of rapid method for urine analysis by employing high-pressure photon ionization time-of-flight mass spectrometry (HPPI-TOFMS) combined with dynamic purge-injection...
May 30, 2018: Analytica Chimica Acta
Jordan Fine, Deepak Verma, Curtis F Jones, Curt Wittig, Andrey F Vilesov
Electron impact ionization of superfluid helium droplets containing several thousand atoms produces a broad distribution of Hen+ ions that peaks at n = 2 and decreases monotonically toward larger n. In larger droplets (say 105 or more atoms), however, the He4+ signal intensity is anomalously large. We have studied the mechanism for the formation of He4+ ions in large helium droplets by varying the duration of the electron impact excitation pulse. Droplets of different average sizes were generated using the expansion of helium at 20 bars and 9-20 K through a pulsed valve nozzle...
January 28, 2018: Journal of Chemical Physics
Elin Näsström, Pär Jonsson, Anders Johansson, Sabina Dongol, Abhilasha Karkey, Buddha Basnyat, Nga Tran Vu Thieu, Tan Trinh Van, Guy E Thwaites, Henrik Antti, Stephen Baker
BACKGROUND: Salmonella Typhi and Salmonella Paratyphi A are the agents of enteric (typhoid) fever; both can establish chronic carriage in the gallbladder. Chronic Salmonella carriers are typically asymptomatic, intermittently shedding bacteria in the feces, and contributing to disease transmission. Detecting chronic carriers is of public health relevance in areas where enteric fever is endemic, but there are no routinely used methods for prospectively identifying those carrying Salmonella in their gallbladder...
January 26, 2018: PLoS Neglected Tropical Diseases
Chris E Freye, Nicholas R Moore, Robert E Synovec
The complementary information provided by tandem ionization time-of-flight mass spectrometry (TI-TOFMS) is investigated for comparative discovery-based analysis, when coupled with comprehensive two-dimensional gas chromatography (GC × GC). The TI conditions implemented were a hard ionization energy (70 eV) concurrently collected with a soft ionization energy (14 eV). Tile-based Fisher ratio (F-ratio) analysis is used to analyze diesel fuel spiked with twelve analytes at a nominal concentration of 50 ppm...
January 11, 2018: Journal of Chromatography. A
Thankan Jayasekharan, Shyam L Gupta, Vikas Dhiman
The intrinsic binding ability of seven natural peptides (oxytocin, arg8 -vasopressin, bradykinin, angiotensin-I, substance-P, somatostatin, and neurotensin) with copper in two different oxidation states (CuI/II ) derived from different Cu+/2+ precursor sources have been investigated for their charge dependent binding characteristics. The peptide-CuI/II complexes, [M - (n-1)H + nCuI ] and [M - (2n-1)H + nCuII ] are prepared/generated by the reaction of peptides with CuI solution/Cu-target and CuSO4 solution, and are analyzed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS)...
January 15, 2018: Journal of Mass Spectrometry: JMS
Megan R Showalter, Eric B Nonnecke, A L Linderholm, Tomas Cajka, Michael R Sa, Bo Lönnerdal, Nicholas J Kenyon, Oliver Fiehn
Obesity and accompanying metabolic disease is negatively correlated with lung health yet the exact mechanisms by which obesity affects the lung are not well characterized. Since obesity is associated with lung diseases as chronic bronchitis and asthma, we designed a series of experiments to measure changes in lung metabolism in mice fed obesogenic diets. Mice were fed either control or high fat/sugar diet (45%kcal fat/17%kcal sucrose), or very high fat diet (60%kcal fat/7% sucrose) for 150 days. We performed untargeted metabolomics by GC-TOFMS and HILIC-QTOFMS and lipidomics by RPLC-QTOFMS to reveal global changes in lung metabolism resulting from obesity and diet composition...
2018: PloS One
Jingcheng Wang, Yuanlong Hou, Zhiying Jia, Xie Xie, Jiajian Liu, Yani Kang, Xin Wang, Xiaoyan Wang, Wei Jia
Different components of Panax ginseng have different properties and medicinal effects. Metabonomics was a prospective approach to analyze the global response of endogenous metabolites to physiological and pathological processes. In this study, an untargeted metabonomics method using GC/TOFMS combined with multivariate statistical techniques was applied to compare entire metabolite differences and the antistress variations among four components of P. ginseng, namely, total ginsenosides (TG), panaxadiol (PD), panaxatriol (PT), and ginseng polysaccharide (PS), in Wistar rats...
February 2, 2018: Journal of Proteome Research
Daguang Wang, Wei Li, Qi Zou, Lei Yin, Yechao Du, Jingkai Gu, Jian Suo
Objective: This study was aimed to investigate serum metabolites in gastric cancer (GC) patients and their relationships with the prognosis of GC in order to find potential specific serum biomarkers for GC. Methods: Blood samples of 125 GC patients of unifocal GC at initial stage and 38 healthy people recruited in our hospital from September 2008 to August 2009 were analyzed by using high performance liquid chromatography coupled with electrospray ionization/quadrupole-time-of-flight mass spectrometry (HPLCESI/Q-TOFMS)...
December 15, 2017: Oncotarget
In-Young Chung, Yu-Mi Park, Hyun-Jeoung Lee, Hyuk Kim, Dong-Hoon Kim, Il-Gyu Kim, Sang-Min Kim, Young-Sun Do, Kwang-Seol Seok, Jung-Hwan Kwon
It is thought that there are many unregulated anthropogenic chemicals in the environment. For risk assessment of chemicals, it is essential to estimate the predicted environmental concentrations. As an effort of identifying residual organic contaminants in air and water in Korea, nontarget screening using two-dimensional gas chromatography time-of-flight mass spectrometry (GC×GC-TOFMS) was conducted at 10 sites using polyurethane foam passive air sampler and at 6 sites using polydimethyl siloxane (PDMS) passive water sampler in three different seasons in 2014...
December 2017: Journal of Environmental Sciences (China)
Zhisen Liang, Shudi Zhang, Xiaoping Li, Tongtong Wang, Yaping Huang, Wei Hang, Zhilin Yang, Jianfeng Li, Zhongqun Tian
Spectroscopic methods with nanoscale lateral resolution are becoming essential in the fields of physics, chemistry, geology, biology, and materials science. However, the lateral resolution of laser-based mass spectrometry imaging (MSI) techniques has so far been limited to the microscale. This report presents the development of tip-enhanced ablation and ionization time-of-flight mass spectrometry (TEAI-TOFMS), using a shell-isolated apertureless silver tip. The TEAI-TOFMS results indicate the capability and reproducibility of the system for generating nanosized craters and for acquiring the corresponding mass spectral signals...
December 2017: Science Advances
Brian J Malys, Michelle L Piotrowski, Kevin G Owens
Frustrated by worse than expected error for both peak area and time-of-flight (TOF) in matrix assisted laser desorption ionization (MALDI) experiments using samples prepared by electrospray deposition, it was finally determined that there was a correlation between sample location on the target plate and the measured TOF/peak area. Variations in both TOF and peak area were found to be due to small differences in the initial position of ions formed in the source region of the TOF mass spectrometer. These differences arise largely from misalignment of the instrument sample stage, with a smaller contribution arising from the non-ideal shape of the target plates used...
February 2018: Journal of the American Society for Mass Spectrometry
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