keyword
MENU ▼
Read by QxMD icon Read
search

Esi

keyword
https://www.readbyqxmd.com/read/29793194/simultaneous-determination-of-18-psychoactive-agents-and-6-metabolites-in-plasma-using-lc-ms-ms-and-application-to-actual-plasma-samples-from-conscription-candidates
#1
Dongeun Park, Hyeyoung Choi, Moonhee Jang, Hyejin Chang, Sanghee Woo, Wonkyung Yang
In Korea, an increasing number of people attempt to evade military conscription by posing as mental health patients. To verify the authenticity of mental illness, there is a need to detect wide range of psychoactive agents in biological specimens of conscription candidates. In this study, we developed and validated a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for simultaneous determination of 18 psychoactive agents and 6 metabolites in human plasma. The method was characterized by the use of a simple, fast and cheap protein precipitation as sample preparation, a rapid run time (11min) and a low volume of plasma sample (200μL)...
April 22, 2018: Forensic Science International
https://www.readbyqxmd.com/read/29793098/evaluation-of-analgesic-and-anti-inflammatory-activities-of-rubia-cordifolia-l-by-spectrum-effect-relationships
#2
REVIEW
Cai-Hong Shen, Cui-Ting Liu, Xiao-Juan Song, Wei-Ya Zeng, Xiao-Ying Lu, Zuo-Liang Zheng, Jie-Pan, Ruo-Ting Zhan, Ping-Yan
The objective of the current work was to evaluate the spectrum-effect relationships between high-performance liquid chromatography fingerprints and analgesic and anti-inflammatory effects of Rubia cordifolia L. extract (RCE), and to identify active components of RCE. Chemical fingerprints of ten batches of RC from various sources were obtained by HPLC, and similarity and hierarchical clustering analyses were carried out. Pharmacodynamic assays were performed in adjuvant-induced arthritis rat model to assess the analgesic and anti-inflammatory properties of RCE...
May 17, 2018: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
https://www.readbyqxmd.com/read/29793031/cloning-overexpression-and-purification-of-a-gene-of-unknown-function-of-prophage-loci-from-candidatus-liberibacter-asiaticus-the-destructive-bacterial-pathogen-of-huanglongbing-disease-in-citrus-plants
#3
Duangtip Sudhan, Thamrongjet Puttamuk, Supachai Vuttipongchaikij, Pitak Chuawong
Citrus Huanglongbing (HLB) or citrus greening is one of the most destructive diseases affecting citrus industry worldwide. The causal agent in Asia is a phloem-limited, Gram-negative bacterium, 'Candidatus Liberibacter asiaticus' (CLas). Within the genome of CLas lies prophage regions, classified as Type-A, B, C, and D. In particular, Type-D has been indicated to correlate with the blotchy-mottle symptoms of citrus trees. Here we reported the cloning, overexpression, and purification of the ORF1, an open reading frame from the partial Type-D region of CLas obtained from an infected lime tree (Citrus aurantifolia Swingle)...
May 21, 2018: Protein Expression and Purification
https://www.readbyqxmd.com/read/29792807/micelles-protect-intact-metallo-supramolecular-block-copolymer-complexes-from-solution-to-gas-phase-during-electrospray-ionization
#4
Kai Hung Huang, Tsung-Han Tu, Shi-Cheng Wang, Yi-Tsu Chan, Cheng-Chih Hsu
Supramolecular diblock copolymers using metal-ligand coordination can be synthesized under ambient conditions by delicate design of the end groups of the homopolymer chains. However, mass spectrometric analysis of such metallo-supramolecular copolymers is challenging. One of the reasons is the nonpolarity of the polymer chains, making it hard to disperse the complexes in electrospray ionization (ESI)-friendly environments. The other difficulty is the noncovalent nature of such copolymers, which is easily disrupted during the ionization...
May 24, 2018: Analytical Chemistry
https://www.readbyqxmd.com/read/29792796/nano-lc-nsi-ms-refines-lipidomics-by-enhancing-lipid-coverage-measurement-sensitivity-and-linear-dynamic-range
#5
Niklas Danne-Rasche, Cristina Coman, Robert Ahrends
Nano-liquid chromatography (nLC) - nano-electrospray (NSI) is one of the cornerstones of mass spectrometry based bioanalytics. Nevertheless, the application of nLC is not prevailing lipid analyses so far. In this study, we established a reproducible nLC separation for global lipidomics and describe the merits of using such a miniaturized system for lipid analyses. In order to enable comprehensive lipid analyses that is not restricted to specific lipid classes, we particularly optimized sample preparation conditions and reversed phase separation parameters...
May 24, 2018: Analytical Chemistry
https://www.readbyqxmd.com/read/29792332/ligation-enhanced-%C3%AF-hole%C3%A2-%C3%A2-%C3%A2-%C3%AF-interactions-involving-isocyanides-effect-of-%C3%AF-hole%C3%A2-%C3%A2-%C3%A2-%C3%AF-noncovalent-bonding-on-conformational-stabilization-of-acyclic-diaminocarbene-ligands
#6
Alexander S Mikherdov, Mikhail A Kinzhalov, Alexander S Novikov, Vadim P Boyarskiy, Irina A Boyarskaya, Margarita S Avdontceva, Vadim Yu Kukushkin
The reaction of cis-[PdCl2 (CNXyl)2 ] (Xyl = 2,6-Me2 C6 H3 ) with the aminoazoles [1 H-imidazol-2-amine (1), 4 H-1,2,4-triazol-3-amine (2), 1 H-tetrazol-5-amine (3), 1 H-benzimidazol-2-amine (4), 1-alkyl-1 H-benzimidazol-2-amines, where alkyl = Me (5), Et (6)] in a 2:1 ratio in the presence of a base in CHCl3 at RT proceeds regioselectively and leads to the binuclear diaminocarbene complexes [(ClPdCNXyl)2 {μ-C(N-azolyl)N(Xyl)C═NXyl}] (7-12; 73-91%). Compounds 7-12 were characterized by C, H, N elemental analyses, high-resolution ESI+ -MS, Fourier transform infrared spectroscopy, 1D (1 H, 13 C) and 2D (1 H,1 H-COSY, 1 H,1 H-NOESY, 1 H,13 C-HSQC, 1 H,13 C-HMBC) NMR spectroscopies, and X-ray diffraction (XRDn)...
May 24, 2018: Inorganic Chemistry
https://www.readbyqxmd.com/read/29791485/alterations-in-the-brain-interactome-of-the-intrinsically-disordered-n-terminal-domain-of-the-cellular-prion-protein-prpc-in-alzheimer-s-disease
#7
Sarah Ulbrich, Petra Janning, Ralf Seidel, Jakob Matschke, Anika Gonsberg, Sebastian Jung, Markus Glatzel, Martin Engelhard, Konstanze F Winklhofer, Jörg Tatzelt
The cellular prion protein (PrPC) is implicated in neuroprotective signaling and neurotoxic pathways in both prion diseases and Alzheimer's disease (AD). Specifically, the intrinsically disordered N-terminal domain (N-PrP) has been shown to interact with neurotoxic ligands, such as Aβ and Scrapie prion protein (PrPSc), and to be crucial for the neuroprotective activity of PrPC. To gain further insight into cellular pathways tied to PrP, we analyzed the brain interactome of N-PrP. As a novel approach employing recombinantly expressed PrP and intein-mediated protein ligation, we used N-PrP covalently coupled to beads as a bait for affinity purification...
2018: PloS One
https://www.readbyqxmd.com/read/29791149/a-tricopper-i-complex-competent-for-o-atom-transfer-c-h-bond-activation-and-multiple-o-2-activation-steps
#8
Brian J Cook, Gianna N Di Francesco, Matthew T Kieber-Emmons, Leslie J Murray
Oxygenation of a tricopper(I) cyclophanate (1) affords reactive transients competent for C-H bond activation and O atom transfer to various substrates (including toluene, dihydroanthracene, and ethylmethylsulfide) based on 1 H NMR, gas chromatography/mass spectrometry (MS), and electrospray ionization (ESI)/MS data. Low product yields (<1%) are determined for C-H activation substrates (e.g, toluene, ethylbenzene), which we attribute to competitive ligand oxidation. The combined stopped-flow UV/visible, electron paramagnetic resonance, ESI/MS, 1 H NMR, and density functional theory (DFT) results for reaction of 1 with O2 are consistent with transient peroxo- and di(oxo)-bridged intermediates...
May 23, 2018: Inorganic Chemistry
https://www.readbyqxmd.com/read/29790879/exploring-matrix-effects-and-quantifying-organic-additives-in-hydraulic-fracturing-associated-fluids-using-liquid-chromatography-electrospray-ionization-mass-spectrometry
#9
Marika Nell, Damian E Helbling
Hydraulic fracturing (HF) operations utilize millions of gallons of water amended with chemical additives including biocides, corrosion inhibitors, and surfactants. Fluids injected into the subsurface return to the surface as wastewaters, which contain a complex mixture of additives, transformation products, and geogenic chemical constituents. Quantitative analytical methods are needed to evaluate wastewater disposal alternatives or to conduct adequate exposure assessments. However, our narrow understanding of how matrix effects change the ionization efficiency of target analytes limits the quantitative analysis of polar to semi-polar HF additives by means of liquid chromatography electrospray ionization mass spectrometry (LC-ESI-MS)...
May 23, 2018: Environmental Science. Processes & Impacts
https://www.readbyqxmd.com/read/29790547/melissa-officinalis-l-ethanolic-extract-inhibits-the-growth-of-a-lung-cancer-cell-line-by-interfering-with-the-cell-cycle-and-inducing-apoptosis
#10
D B Magalhães, I Castro, V Lopes-Rodrigues, J M Pereira, L Barros, I C F R Ferreira, C P R Xavier, M H Vasconcelos
Melissa officinalis is a plant from the family Lamiaceae, native in Europe particularly in the Mediterranean region. Given our interest in identifying extracts and compounds capable of inhibiting tumor cell growth, and given the antioxidant content and the high consumption of Melissa officinalis in Portugal, this study aimed to test the tumor cell growth inhibitory activity of five different extracts of this plant (aqueous, methanolic, ethanolic, hydromethanolic and hydroethanolic) in three human tumor cell lines: MCF-7, AGS and NCI-H460...
May 23, 2018: Food & Function
https://www.readbyqxmd.com/read/29789170/method-selectivity-evaluation-using-the-co-feature-ratio-in-lc-ms-metabolomics-comparison-of-hilic-stationary-phase-performance-for-the-analysis-of-plasma-urine-and-cell-extracts
#11
Albert Elmsjö, Jakob Haglöf, Mikael K R Engskog, Ida Erngren, Marika Nestor, Torbjörn Arvidsson, Curt Pettersson
Evaluation of the chromatographic separation in metabolomics studies has primarily been done using preselected sets of standards or by counting the number of detected features. An alternative approach is to calculate each feature's co-feature ratio, which is a combined selectivity measurement for the separation (i.e. extent of co-elution) and the MS-signal (i.e. adduct formation and in-source fragmentation). The aim of this study was to demonstrate how the selectivity of different HILIC stationary phases can be evaluated using the co-feature ratio approach...
May 4, 2018: Journal of Chromatography. A
https://www.readbyqxmd.com/read/29787972/investigation-by-direct-infusion-esi-ms-and-gc-ms-of-an-alleged-leuckart-route-specific-impurity-of-methamphetamine
#12
Ethan M McBride, Guido F Verbeck
Impurity profiling has been used as a useful tool for analyzing nearly every drug class currently known on the illicit market. Impurities present within seized samples have the potential to determine source of origin, route of synthesis used, as well as provide a useful clue into the potential reaction mechanisms that are present for each synthetic procedure. Perhaps the most well studied of these impurity profiles exists for methamphetamine, including information to more than one route of synthesis. Within the present study, a complete synthesis of methamphetamine was performed, including a reductive amination of phenylpropanone (P2P) using methylamine hydrochloride and sodium triacetoxyborohydride (STAB) rather than the conventional aluminum mercury amalgam commonly found in the literature...
May 16, 2018: Forensic Science International
https://www.readbyqxmd.com/read/29787846/chemical-study-antioxidant-anti-hypertensive-and-cytotoxic-cytoprotective-activities-of-centaurea-cyanus-l-petals-aqueous-extract
#13
Graziela Bragueto Escher, Jânio Sousa Santos, Neiva Deliberali Rosso, Mariza Boscacci Marques, Luciana Azevedo, Mariana Araújo Vieira do Carmo, Heitor Daguer, Luciano Molognoni, Leonardo do Prado-Silva, Anderson Souza Sant'Ana, Marcia Cristina da Silva, Daniel Granato
This study aimed to optimise the experimental conditions of extraction of the phytochemical compounds and functional properties of Centaurea cyanus petals. The following parameters were determined: the chemical composition (LC-ESI-MS/MS), the effects of pH on the stability and antioxidant activity of anthocyanins, the inhibition of lipid peroxidation, antioxidant activity, anti-hemolytic activity, antimicrobial, anti-hypertensive, and cytotoxic/cytoprotective effect, and the measurements of intracellular reactive oxygen species...
May 19, 2018: Food and Chemical Toxicology
https://www.readbyqxmd.com/read/29786099/cluster-to-cluster-transformation-among-au-6-au-8-and-au-11-nanoclusters
#14
Xiuqing Ren, Junhong Fu, Xinzhang Lin, Xuemei Fu, Jinghui Yan, Ren'an Wu, Chao Liu, Jiahui Huang
We present the cluster-to-cluster transformations among three gold nanoclusters, [Au6(dppp)4]2+ (Au6), [Au8(dppp)4Cl2]2+ (Au8) and [Au11(dppp)5]3+ (Au11). The conversion process follows a rule that states that the transformation of a small cluster to a large cluster is achieved through an oxidation process with an oxidizing agent (H2O2) or with heating, while the conversion of a large cluster to a small one occurs through a reduction process with a reducing agent (NaBH4). All the reactions were monitored using UV-Vis spectroscopy and ESI-MS...
May 22, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29785738/mass-spectrometry-for-characterization-of-homologous-piperidine-alkaloids-and-their-activity-as-acetylcholinesterase-inhibitors
#15
Thamires R Freitas, Amanda Danuello, Claudio Viegas Júnior, Vanderlan S Bolzani, Marcos Pivatto
RATIONALE: Piperidine alkaloids from Senna spectabilis constitute a rare class of natural products with several biological activities. However, the absence of chromophores makes their structural elucidation by conventional methods a great challenge. In this context, mass spectrometry emerges as a powerful tool for metabolomics studies. METHODS: The piperidine alkaloids (-)-cassine and (-)-spectaline and the semisynthetic derivatives (-)-3-O-acetylcassine and (-)-3-O-acetylspectaline were investigated by electrospray ionization tandem mass spectrometry (ESI-MS/MS) in the positive mode and electron ionization mass spectrometry (EI-MS)...
May 22, 2018: Rapid Communications in Mass Spectrometry: RCM
https://www.readbyqxmd.com/read/29784072/high-throughput-quantitation-of-neonicotinoids-in-lyophilized-surface-water-by-lc-apci-ms-ms
#16
Lucas M Morrison, Justin B Renaud, Lyne Sabourin, Mark W Sumarah, Ken K C Yeung, David R Lapen
Background : Neonicotinoids are among the most widely used insecticides. Recently, there has been concern associated with unintended adverse effects on honeybees and aquatic invertebrates at low parts-per-trillion levels. Objective : There is a need for LC-MS/MS methods that are capable of high-throughput measurements of the most widely used neonicotinoids at environmentally relevant concentrations in surface water. Methods : This method allows for quantitation of acetamiprid, clothianidin, imidacloprid, dinotefuran, nitenpyram, thiacloprid, and thiamethoxam in surface water...
May 21, 2018: Journal of AOAC International
https://www.readbyqxmd.com/read/29783635/glycosaminoglycans-from-a-sea-snake-lapemis-curtus-extraction-structural-characterization-and-antioxidant-activity
#17
Mingyue Bai, Wenwei Han, Xia Zhao, Qingchi Wang, Yanyun Gao, Shiming Deng
Sea snakes have wide application prospects in medicine, health food and other fields. Several novel polysaccharides were successfully obtained from the skin and the meat of a sea snake ( Lapemis curtus ). The structures of polysaccharides LSP3 and LMP3, which were extracted and purified from Lapemis curtus , were determined to be new and highly heterogenic glycosaminoglycans (GAGs) by means of FT-IR, ESI-MS/MS and NMR. LSP3 is a hybrid dermatan sulfate (DS) and composed of 48% 4-sulfated disaccharides (Di4S), 42% 6-sulfated disaccharides (Di6S) and 5% disulfated disaccharides (Di2,6S), while LMP3 is a hybrid chondroitin sulfate (CS) and composed of 70% Di4S, 20% Di6S, and 8% Di2,6S...
May 18, 2018: Marine Drugs
https://www.readbyqxmd.com/read/29782035/simultaneous-quantitation-of-rosuvastatin-and-ezetimibe-in-human-plasma-by-lc-ms-ms-pharmacokinetic-study-of-fixed-dose-formulation-and-separate-tablets
#18
Abhaysingh Bhadoriya, Mallika Sanyal, Priyanka A Shah, Pranav S Shrivastav
A simple, high-throughput and highly sensitive liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) method has been developed for the simultaneous estimation of rosuvastatin and free ezetimibe. Liquid-liquid extraction was carried out using methyl-tert butyl ether after prior acidification from 300 μL human plasma. The recovery for both the analytes and their deuterated internal standards (ISs) ranged from 95.7-99.8 %. Rosuvastatin and ezetimibe were separated on Symmetry C18 column using acetonitrile and ammonium formate buffer, pH 3...
May 21, 2018: Biomedical Chromatography: BMC
https://www.readbyqxmd.com/read/29782002/quantitative-and-qualitative-method-for-sphingomyelin-by-lc-ms-using-two-stable-isotopically-labeled-sphingomyelin-species
#19
Kotaro Hama, Yuko Fujiwara, Kazuaki Yokoyama
We present a method of analyzing sphingomyelin (SM) qualitatively and quantitatively by liquid chromatography-electrospray Ionization-tandem mass spectrometry (LC-ESI-MS/MS). SM is a common sphingolipid composed of a phosphorylcholine and a ceramide as the hydrophilic and hydrophobic component, respectively. A number of SM species are present in mammalian cells due to a variety in the sphingoid long chain base (LCB) and an N-acyl moiety in the ceramide. In this report, we show a method of estimating the number of carbon and double bonds in a LCB and an N-acyl moiety based on their corresponding product ions in MS/MS/MS (MS3 ) experiments...
May 7, 2018: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/29781312/diterpenoid-alkaloids-from-delphinium-naviculare-var-lasiocarpum-with-their-antifeedant-activity-on-spodoptera-exigua
#20
Lianhai Shan, Lin Chen, Feng Gao, Xianli Zhou
A new lycoctonine diterpenoid alkaloid navicularine, along with eighteen known diterpenoid alkaloids, were isolated from the whole plant of Delphinium naviculare var. lasiocarpum. Their structures were elucidated on the base of extensive spectroscopic analysis (HR-ESI-MS and NMR) and comparison with data reported in the literature. Most of alkaloids were tested for their antifeedant activity against larvae of Spodoptera exigua (Hübner). The compound shawurensine showed considerably potent antifeedant activity (EC50 = 0...
May 21, 2018: Natural Product Research
keyword
keyword
40713
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"