Read by QxMD icon Read

formic acid

Yilin Sun, Le Zhen, Ying Peng, Jiankun Wang, Fei Fei, Lixiang Aa, Wenjiao Jiang, Xue Pei, Li Lu, Jie Liu, Guangji Wang, Kun Hao
To improve bioavailability and provide resistance to deamination, an array of gemcitabine (dFdC) prodrugs carrying the acyl modifications has been successful in the optimization of pharmacokinetic properties of dFdC, but the reports about 4-N-carbobenzoxy-dFdC (Cbz-dFdC), a dFdC prodrug bearing alkyloxycarbonyl modification, are relatively rare. Notably, in vivo enzymatic hydrolysis was an absolutely essential factor for the activation of these prodrugs, which is correlated with the anti-tumor activity. Therefore, detailed metabolism studies of Cbz-dFdC should be carried out for a more authentic pharmacodynamic evaluation...
March 14, 2018: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Morteza Karimzadeh, Neda Manouchehri, Dariush Saberi, Khodabakhsh Niknam
All 66 conformers of guanylurea were optimized and frequency calculations were performed at M06-2X/6-311++G(d,p) level of theory. Theses conformers were categorized into five tautomers, and the most stable conformer of each tautomer were found. Geometrical parameters indicated that these tautomers have almost planar structure. Complete stepwise tautomerism were studied through both intramolecular proton transfer routs and internal rotations. Results indicated that the proton transfer routs involving four-membered heterocyclic structures were rate-determining steps...
March 6, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Yu Xiong, Pingyu Xin, Wenxing Chen, Yu Wang, Shaolong Zhang, Hanlin Ren, Hongpan Rong, Xusheng Zheng, Chen Chen, Qing Peng, Dingsheng Wang, Yadong Li
We successfully obtained truncated octahedron PtAl alloy nanocrystals (∼10 nm) via a facile one-pot strategy. The PtAl nanocrystals exhibited enhanced activity in formic acid electrooxidation compared to commercial Pt/C, which could be ascribed to the large density of defects on the surface as well as the synergy between Pt and Al.
March 20, 2018: Chemical Communications: Chem Comm
Manuel Iglesias, Luis A Oro
This review summarises the most recent advances in Ir-NHC catalysis while revisiting all the classical reactions in which this type of catalyst has proved to be active. The influence of the ligand system and, in particular, the impact of the NHC ligand on the activity and selectivity of the reaction have been analysed, accompanied by an examination of the great variety of catalytic cycles hitherto reported. The reaction mechanisms so far proposed are described and commented on for each individual process. Moreover, some general considerations that attempt to explain the influence of the NHC from a mechanistic viewpoint are presented at the end of the review...
March 20, 2018: Chemical Society Reviews
Hongliang Li, Liangbing Wang, Yizhou Dai, Zhengtian Pu, Zhuohan Lao, Yawei Chen, Menglin Wang, Xusheng Zheng, Junfa Zhu, Wenhua Zhang, Rui Si, Chao Ma, Jie Zeng
Exploring the interaction between two neighbouring monomers has great potential to significantly raise the performance and deepen the mechanistic understanding of heterogeneous catalysis. Herein, we demonstrate that the synergetic interaction between neighbouring Pt monomers on MoS2 greatly enhanced the CO2 hydrogenation catalytic activity and reduced the activation energy relative to isolated monomers. Neighbouring Pt monomers were achieved by increasing the Pt mass loading up to 7.5% while maintaining the atomic dispersion of Pt...
March 19, 2018: Nature Nanotechnology
Mahendra Shukla, Femi M Francis, Jawahar Lal
Conessine, a steroidal alkaloid obtained from the bark and seeds of the plant species of Apocynaceae family, elicits a histamine antagonistic action, selectively for the H3 histaminergic receptors. This alkaloid is used mainly for the treatment of dysentery and helminthic disorders. For the quantification of conessine in serum, a liquid chromatography-tandem mass spectrometry method was developed. Chromatographic separation was achieved on a Zorbax SB-CN column (100 × 4.6 mm, 3.5 µm), and a mobile phase consisting of 90% methanol in aqueous ammonium acetate buffer (pH 3...
January 1, 2018: European Journal of Mass Spectrometry
Yi Zhou, Qingqing Chang, Wenjie Wang, Xiaofang Zhang, Fang Zhou, Jianguo Sun, Guangji Wang, Ying Peng
FY363 is a new chemical entity of gemcitabine analog, which has been shown to have a significant inhibitory effect on cell proliferation in a variety of tumor cell lines in vitro. As a carbamate derivative, FY363 would be converted to the active metabolite gemcitabine through enzyme action in vivo. In order to clarify the exposure of FY363 prototype and its metabolite gemcitabine in vivo after administration of FY363, a sensitive and specific liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed and validated to simultaneously determine FY363 and gemcitabine in rat plasma after liquid-liquid extraction with ethyl acetate...
March 14, 2018: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Yan-Ru Liu, Zhi-Shu Tang, Jin-Ao Duan, Xiao-Chun Sun, Zhong-Xing Song, Xin-Bo Shi, Yang Lv, Zhao Zhang, Da-Wei Qian
To explore the flavor and meridian tropism classification of Callianthemum taipaicum by principal components analysis(PCA) and partial least square analysis(PLS). Meanwhile,to establish a high performance liquid chromatography-tandem mass spectrometry(HPLC-ESI-MS) method for the simultaneous determination of 55 active components from 13 kinds of Ranunculaceae of Chinese traditional herbs. Samples were separated on HPLC system by Agilent 5 TC-C₁₈(2)(4.6 mm×250 mm,5 μm)column and eluted with acetonitrile and 0...
January 2018: Zhongguo Zhong Yao za Zhi, Zhongguo Zhongyao Zazhi, China Journal of Chinese Materia Medica
Wen-Jing Zhao, Mo-Ran Huang, Zhan-Peng Shang, Zi-Jian Wang, Zhi-Bin Wang, Jia-Yu Zhang
An efficient method of ultra-high performance liquid chromatography coupled with linear ion trap-Orbitrap (UHPLC-LTQ-Orbitrap) mass spectrometer was established to elucidate the in vivo metabolites of tanshinone Ⅰ and tanshinone ⅡA in rats. Urine and plasma samples were collected after oral gavage. After processing biological sample by solid phase extraction, Waters ACQUITY HPLC BEH C₁₈ column (2.1 mm×100 mm, 1.7 μm) was used with 0.1% formic acid (A) - acetonitrile (B) solution as the mobile phase for gradient elution...
January 2018: Zhongguo Zhong Yao za Zhi, Zhongguo Zhongyao Zazhi, China Journal of Chinese Materia Medica
Ai-Hua Wang, Li-Man Ma, Shan-Shan Fan, Guang-Xue Liu, Feng Xu, Ming-Ying Shang, Shao-Qing Cai
This experiment was performed to analyze and identify the chemical constituents of Sinopodophylli Fructus by HPLC-DAD-ESI-IT-TOF-MSn. The analysis was performed on an Agilent Zorbax SB-C₁₈ (4.6 mm×250 mm, 5 μm) column.The mobile phase consisted of 0.1% formic acid was used for gradient at a flow rate of 1.0 mL·min⁻¹. Electrospray ionization ion trap time-of-flight multistage mass spectrometry was applied for qualitative analysis under positive and negative ion modes. The results indicated that 54 compounds consisted of 18 lignans and 36 flavonoids from Xiaoyelian had been detected by their HRMS data, the information of literature and reference substance...
January 2018: Zhongguo Zhong Yao za Zhi, Zhongguo Zhongyao Zazhi, China Journal of Chinese Materia Medica
Xie-An Yu, John Teye Azietaku, Jin Li, Hui Wang, Fang Zheng, Jia Hao, Yan-Xu Chang
Ardisia japonica is a well-known traditional Chinese medicinal herb used as a diuretic, for treating cough and for stopping uterine bleeding. A simple, sensitive, and reliable LC-MS/MS method was developed to determine six active compounds in rat plasma and this method was further applied to the pharmacokinetic study of these compounds after oral administration of Ardisia japonica extract. Acetonitrile was used to precipitate the protein in the plasma samples. Using acetonitrile and formic acid aqueous solution (0...
2018: Evidence-based Complementary and Alternative Medicine: ECAM
Claudia Spatari, Wenlong Li, Alfred H Schinkel, Gaetano Ragno, Jan H M Schellens, Jos H Beijnen, Rolf W Sparidans
A bio-analytical assay for the first third generation ALK inhibitor lorlatinib in mouse plasma was developed and validated. Ten-μl plasma samples were prepared by adding rucaparib as the internal standard and precipitation of the plasma proteins. For LC-MS/MS analysis, compounds were eluted at 0.5 mL/min and separated on a 3-μm particle-size, polar embedded octadecyl silica column by gradient elution using 0.1% of formic acid (in water) and methanol. Compounds were monitored with positive electrospray ionization using a triple quadrupole mass spectrometer in selected reaction monitoring mode...
March 9, 2018: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Ji Ye, Yanxia Gao, Saisai Tian, Juan Su, Weidong Zhang
BACKGROUND: Panax ginseng (PG) is one of the most valuable and frequently used phytomedicine in Asia. In the current Chinese Pharmacopeia, only three ginsenosides, Rg1, Re and Rb1, were set as standard compounds for the quality evaluation of PG. However, only these three compounds could hardly reflect the quality and therapeutic efficacy of this traditional Chinese medicine (TCM). PURPOSE: Quantification analysis of quality markers (Q-markers) in PG is meaningful for determining the quality of this herbal medicine...
February 28, 2018: Phytomedicine: International Journal of Phytotherapy and Phytopharmacology
Bartosz Baran, Michał Krzyżowski, Mikołaj Cup, Jakub Janiec, Mateusz Grabowski, Jacek Francikowski
Volatile fatty acids (VFAs) are a group of common metabolites and semiochemicals mediating information transfer between higher organisms and bacteria, either from microbiome or external environment. VFAs commonly occur among various insect orders. There are numerous studies exploring their influence on the behavior of different insect species. In relation to the papers published by J. E. McFarlane in 1985, we assessed the effects of formic, acetic, propionic, butyric and valeric acids on the spatial preference of the lesser mealworm ( Alphitobius diaperinus ), a common pest of stored food grain products and the poultry industry...
March 16, 2018: Insects
Wenge Chen, Yunlong Cheng, Jianzhong Chen, Jiahang Chen, Kai Jiang, Yuyang Zhou, Lee Jia
Mifepristone (RU486) is developed originally as a contraceptive used by hundreds of millions of women world-wide, and also reported as a safe and long-term psychotic depressant, or as a cancer chemotherapeutic agent used by both sexes. In our preliminary study aimed at developing mifepristone as a cancer metastatic chemopreventive, we coincidentally observed that blood mifepristone concentrations in female rats seem to be higher than those in male ones post administration. To substantiate if the pharmacokinetic differences between sexes exist, we established a fast UPLC-MS/MS method to determine mifepristone concentrations in plasma, and analyzed blood concentrations of mifepristone over time in rats and dogs of both sexes...
March 8, 2018: Journal of Pharmaceutical and Biomedical Analysis
Junjian Zheng, Zhiwei Wang, Jinxing Ma, Shaoping Xu, Zhichao Wu
Inability to remove low molecular weight anthropogenic contaminants is a critical issue in low-pressure membrane filtration processes for water treatment. In this work, a novel electrochemical ceramic membrane filtration (ECMF) system using TiO2@SnO2-Sb anode was developed for removing persistent p-chloroaniline (PCA). Results showed that the ECMF system achieved efficient removal of PCA from contaminated waters. At a charging voltage of 3 V, the PCA removal rate of TiO2@SnO2-Sb ECMF system under flow-through mode was 2...
March 15, 2018: Environmental Science & Technology
Yun Cao, Zhigang Geng, Weiwei Chen, Fan Cai, Guoxiong Wang, Zhengfei Wang, Jie Zeng
Introducing C-B diatomic groups in carbon-doped hexagonal boron nitride (h-BN) flakes resulted in high activity and selectivity for HCOOH in CO2 electroreduction. The activation of CO2 was prone to occur on B atoms while the activation of the proton occurred on C atoms. The volcano-type relation of Faradaic efficiency for HCOOH production over carbon content originates from the balance of H* and COOH* intermediates in carbon-doped h-BN catalysts.
March 15, 2018: Chemical Communications: Chem Comm
Jia Wu, Adam Elliston, Gwenaelle Le Gall, Ian J Colquhoun, Samuel R A Collins, Ian P Wood, Jo Dicks, Ian N Roberts, Keith W Waldron
Background: Rice straw and husk are globally significant sources of cellulose-rich biomass and there is great interest in converting them to bioethanol. However, rice husk is reportedly much more recalcitrant than rice straw and produces larger quantities of fermentation inhibitors. The aim of this study was to explore the underlying differences between rice straw and rice husk with reference to the composition of the pre-treatment liquors and their impacts on saccharification and fermentation...
2018: Biotechnology for Biofuels
Sopheavy Siek, Dalton B Burks, Deidra L Gerlach, Guangchao Liang, Jamie M Tesh, Courtney R Thompson, Fengrui Qu, Jennifer E Shankwitz, Robert M Vasquez, Nicole Chambers, Gregory J Szulczewski, Douglas B Grotjahn, Charles Edwin Webster, Elizabeth T Papish
Hydrogenation reactions can be used to store energy in chemical bonds, and if these reactions are reversible, that energy can be released on demand. Some of the most effective transition metal catalysts for CO2 hydrogenation have featured pyridin-2-ol-based ligands (e.g., 6,6'-dihydroxybipyridine (6,6'-dhbp)) for both their proton-responsive features and for metal-ligand bifunctional catalysis. We aimed to compare bidentate pyridin-2-ol based ligands with a new scaffold featuring an N -heterocyclic carbene (NHC) bound to pyridin-2-ol...
March 27, 2017: Organometallics
Silvia Zingg, Patrick Dolle, Maarten Jeroen Voordouw, Maren Kern
BACKGROUND: Ticks and tick-borne pathogens are a global problem for the health of humans and their livestock. Wood ants are important ecosystem engineers in forests worldwide. Although both taxa are well studied, little is known about their interactions under natural conditions. The purpose of the present field study was to test whether European red wood ants (Formica polyctena) influence the abundance of Ixodes tick populations in temperate forests. METHODS: Data collection took place in 130 sampling plots located at 26 ant nest sites paired with 26 control sites in northwestern Switzerland...
March 15, 2018: Parasites & Vectors
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"