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https://www.readbyqxmd.com/read/29055247/optimization-and-validation-of-reverse-phase-hplc-method-for-qualitative-and-quantitative-assessment-of-polyphenols-in-seaweed
#1
Gaurav Rajauria
A simple reverse phase-high performance liquid chromatography (RP-HPLC) coupled to a diode array detector (DAD) and negative ion electrospray mass spectrometer (ESI-MS) method was developed for simultaneous identification and quantification of phenolic antioxidants in seaweed. The proposed method was validated in terms of linearity, limits of detection (LOD), limits of quantification (LOQ), recovery and intermediate precision. The calibration curves were linear with correlation coefficient ranging from 0.9909 to 0...
October 13, 2017: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/29055211/bio-affinity-mediated-immobilization-of-lipase-onto-magnetic-cellulose-nanospheres-for-high-yield-biodiesel-in-one-time-addition-of-methanol
#2
Ramesh Bandikari, Jiaxin Qian, Ram Baskaran, Ziduo Liu, Gaobing Wu
To synthesis biodiesel from palm oil in one-time addition of methanol and solvent-free medium using CBD fused with C-terminal of lipase from G. stearothermophilus (GSlip-CBD) was immobilized onto magnetic cellulose nanosphere (MCNS). The immobilized matrix traits were preconceived by FT-IR, TEM and XRD. Perceptible biodiesel yield 98 and 73% was synthesized by GSlip-CBD-MCNS in 4 h and GSlip-MCNS in 6 h under the optimized conditions of oil:methanol ratio (1:3.5), temperature (55 and 50 °C) and enzyme loading (15 U)...
October 3, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/29055193/specific-bioanalytical-optical-and-photoelectrochemical-assays-for-detection-of-methanol-in-alcoholic-beverages
#3
Javier Barroso, Beatriz Díez-Buitrago, Laura Saa, Marco Möller, Nerea Briz, Valeri Pavlov
Methanol is a poison which is frequently discovered in alcoholic beverages. Innovative methods to detect methanol in alcoholic beverages are being constantly developed. We report for the first time a new strategy for the detection of methanol using fluorescence spectroscopy and photoelectrochemical (PEC) analysis. The analytical system is based on the oxidation of cysteine (CSH) with hydrogen peroxide (H2O2) enzymatically generated by alcohol oxidase (AOx). H2O2 oxidizes capping agent CSH, modulating the growth of CSH-stabilized cadmium sulphide quantum dots (CdS QDs)...
October 13, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/29055185/effect-of-the-solvent-on-the-conformational-behavior-of-the-alanine-dipeptide-deduced-from-md-simulations
#4
Jaime Rubio-Martinez, M Santos Tomas, Juan J Perez
In general, peptides do not exhibit a well-defined conformational profile in solution. However, despite the experimental blurred picture associated with their structure, compelling spectroscopic evidence shows that peptides exhibit local order. The conformational profile of a peptide is the result of a balance between intramolecular interactions between different atoms of the molecule and intermolecular interactions between atoms of the molecule and the solvent. Accordingly, the conformational profile of a peptide will change upon the properties of the solvent it is soaked...
October 12, 2017: Journal of Molecular Graphics & Modelling
https://www.readbyqxmd.com/read/29055108/semi-quantitative-analysis-of-tramadol-dextromethorphan-and-metabolites-in-decomposed-skeletal-tissues-by-ultra-performance-liquid-chromatography-quadrupole-time-of-flight-mass-spectrometry-uplc-qtof-ms
#5
H M Cornthwaite, L Labine, J H Watterson
The use of filtration/pass-through extraction (FPTE) and ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-qTOF-MS) to detect tramadol (TRAM), dextromethorphan (DXM) and metabolites from skeletal remains is described. Rats (n=5) received 50 mg/kg tramadol and were euthanized by CO2 asphyxiation approximately 30 min post-dose. Rats (n=4) received 75 mg/kg dextromethorphan and were euthanized by CO2 asphyxiation approximately 45 min post-dose. Remains decomposed to skeleton outdoors and vertebral bones were collected...
October 20, 2017: Drug Testing and Analysis
https://www.readbyqxmd.com/read/29055065/simultaneous-determination-of-usnic-diffractaic-evernic-and-barbatic-acids-in-rat-plasma-by-ultra-high-performance-liquid-chromatography-quadrupole-exactive-orbitrap-mass-spectrometry-and-its-application-to-pharmacokinetic-studies
#6
Hanxue Wang, Tao Yang, Xuemei Cheng, Sukfan Kwong, Chenghai Liu, Rui An, Guowen Li, Xinhong Wang, Changhong Wang
Usnea longissima Ach. (Usnea) has been used in pharmaceuticals, food, cosmetics. Evernic acid (EA), barbatic acid (BA), diffractaic acid (DA), and usnic acid (UA) are the most typical ingredients in U. longissima and exert a wide variety of biological functions. The study aim to develop a sensitive method for simultaneous analysis of EA, BA, DA, and UA in rat plasma and applied to pharmacokinetic studies after consumption of UA and ethanol extract from U. longissima (UE). The samples were separated on BEH C18 column by gradient elution with 0...
October 21, 2017: Biomedical Chromatography: BMC
https://www.readbyqxmd.com/read/29053706/solea-senegalensis-sperm-cryopreservation-new-insights-on-sperm-quality
#7
Marta F Riesco, Catarina Oliveira, Florbela Soares, Paulo J Gavaia, María T Dinis, Elsa Cabrita
Cryopreservation of Senegalese sole sperm can represent an alternative to overcome some reproductive problems of this species. However, it is important to guarantee the safe use of cryopreserved sperm by selecting an appropriate protocol according to a high demand quality need to be ensured. It has been demonstrated that traditional assays such as motility and viability do not provide enough information to identify specific damage caused by cryopreservation process (freezing and thawing). Specific tests, including lipid peroxidation and DNA damage, should be performed...
2017: PloS One
https://www.readbyqxmd.com/read/29053421/development-of-a-novel-herbal-formulation-to-inhibit-biofilm-formation-in-toxigenic-vibrio-cholerae
#8
Diana Jose, N Lekshmi, A K Goel, R Ajay Kumar, Sabu Thomas
Vibrio cholerae, a causative agent of the waterborne disease cholera, still threatens a large proportion of world's population. The role of biofilm formation in V. cholerae pathogenesis is well established, as it provides the bacterium enhanced tolerance to antimicrobial agents and increased transmission. In the present study, four medicinal plants used in traditional medicines with antidiarrheal properties were evaluated for its antibiofilm activity. Methanol extracts of these plants (Centella asiatica, Elephantopus scaber, Camellia sinensis, and Holarrhena antidysenterica) showed promising antibiofilm activity against V...
October 20, 2017: Journal of Food Protection
https://www.readbyqxmd.com/read/29053249/holistic-lipidomics-of-the-human-gut-phenotype-using-validated-ultra-high-performance-liquid-chromatography-coupled-to-hybrid-orbitrap-mass-spectrometry
#9
Lieven Van Meulebroek, Ellen De Paepe, Vicky Vercruysse, Beata Pomian, Simon Bos, Bruno Lapauw, Lynn Vanhaecke
As lipids are assigned a plethora of biological functions, it is evident that a dysregulated lipid metabolism signifies a key element in many pathological conditions. With this rationale, this study presents a validated lipidomics platform to map the fecal lipidome, which integrates unique information about the host-gut microbiome interactions, gastrointestinal functionality, and dietary pattern. This particular method accomplished coverage across all eight lipid categories; the fatty acyls, glycerolipids, phosphoglycerolipids, polyketides, prenols, saccharolipids, sphingolipids, and sterols...
October 20, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/29053242/environmental-effects-on-zirconium-hydroxide-nanoparticles-and-chemical-warfare-agent-decomposition-implications-of-atmospheric-water-and-carbon-dioxide
#10
Robert B Balow, Jeffrey G Lundin, Grant C Daniels, Wesley O Gordon, Monica McEntee, Gregory W Peterson, James H Wynne, Pehr E Pehrsson
Zirconium hydroxide (Zr(OH)4) has excellent sorption properties and wide-ranging reactivity towards numerous types of chemical warfare agents (CWAs) and toxic industrial chemicals. Under pristine laboratory conditions, the effectiveness of Zr(OH)4 has been attributed to a combination of diverse surface hydroxyl species and defects; however, atmospheric components (e.g. CO2, H2O, etc.) and trace contaminants can form adsorbates with potentially detrimental impact to the chemical reactivity of Zr(OH)4. Here, we report the hydrolysis of a chemical warfare agent simulant, dimethyl methylphosphonate (DMMP) on Zr(OH)4 determined by gas chromatography mass spectrometry and in situ attenuated total reflectance Fourier transform infrared spectroscopy under ambient conditions...
October 20, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29052991/transition-metal-single-molecule-magnets-a-mn31-nano-sized-cluster-with-a-large-energy-barrier-of-60-k-and-magnetic-hysteresis-at-5-k
#11
Parisa Abbasi, Kevan Quinn, Dimitris I Alexandropoulos, Marko Damjanović, Wolfgang Wernsdorfer, Albert Escuer, Julia Mayans, Melanie Pilkington, Theocharis C Stamatatos
The first {Mn31} cluster (1) has been prepared from carboxylate ions and the chelating/bridging ligand α-methyl-2-pyridine-methanol. Compound 1 possesses a unique nano-sized structural topology with one of the largest energy barriers reported to-date for high-nuclearity 3d-metal clusters. Single-crystal magnetic hysteresis studies reveal the presence of hysteresis loops below 5 K, one of the highest temperatures below which molecular hysteresis has been observed for 3d-based SMMs.
October 20, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29052981/cation-induced-dimerization-of-crown-substituted-phthalocyanines-by-complexation-with-rubidium-nicotinate-as-revealed-by-x-ray-structural-data
#12
Lyudmila A Lapkina, Vladimir E Larchenko, Gayane A Kirakosyan, Aslan Yu Tsivadze, Sergey I Troyanov, Yulia G Gorbunova
The supramolecular dimeric complex [(μ-oxo)bis(tetra-15-crown-5-phthalocyaninato)(nicotinato)aluminum(III)]tetra(rubidium) bis(nicotinate) was prepared by addition of an excess of a methanol solution of rubidium nicotinate to a chloroform solution of the aluminum crown-phthalocyaninate, [(HO)Al(15C5)4Pc]. A single-crystal X-ray diffraction study of {[Rb4(NicAl(15C5)4Pc)2(μ-O)](2+)(Nic(-))2}·2.36HNic·11H2O demonstrated that two molecules of the aluminum crown-phthalocyaninate nicotinate are connected through an Al-O-Al bridge supported by sandwiching of crown ether moieties by Rb(+) cations...
October 20, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/29052377/-two-new-triterpenoid-acids-from-uighur-medicine-fomes-officinalis
#13
Jian-Xin Han, Tao Yuan
Two new lanostane triterpenoid acids, 12β, 15α-dihydroxy-24-methyl-3,23-dioxo-lanosta-7,9(11)-dien-26-oic acid (1), and 3α, 12β-dihydroxy-24-methyl-7,23-dioxo-lanosta-8-en-26-oic acid (2), were isolated from the methanolic extract of Uighur medicine Fomes officinalis. Their structures were elucidated based on the analysis of spectroscopic data (1D, 2D NMR and HR-MS). Anti-inflammatory and cytotoxicity assays revealed that both compound 1 and 2 show no inhibitory effects on nitric oxide production in lipopolysaccharide-induced RAW264...
April 2017: Zhongguo Zhong Yao za Zhi, Zhongguo Zhongyao Zazhi, China Journal of Chinese Materia Medica
https://www.readbyqxmd.com/read/29052339/structure-activity-and-stability-relationships-for-cobalt-polypyridyl-based-hydrogen-evolving-catalysts-in-water
#14
Stephan Schnidrig, Cyrill Bachmann, Peter Müller, Nicola Weder, Bernhard Spingler, Evelyne Joliat-Wick, Mathias Mosberger, Johannes Windisch, Roger Alberto, Benjamin Probst
A series of eight new and three known cobalt polypyridyl based hydrogen evolving catalysts (HEC), with distinct electronic and structural differences are benchmarked in photocatalytic runs in water. Methylene-bridged bis-bipyridyl is the preferred scaffold, both in terms of stability and rate. For a cobalt complex of the tetradentate, methanol bridged bis-pyridyl-bipyridyl [CoIIBr(tpy)]Br (1a) a detailed mechanistic picture is obtained by combining electrochemistry, spectroscopy and photocatalysis. In the acidic branch, a proton coupled electron transfer (PCET), assigned to formation of CoIII-H, is found upon reduction of CoII, in line with a pKa(CoIII-H) of ~7...
October 19, 2017: ChemSusChem
https://www.readbyqxmd.com/read/29051960/comment-on-relating-side-chain-organization-of-pnipam-with-its-conformation-in-aqueous-methanol-by-d-mukherji-m-wagner-m-d-watson-s-winzen-t-e-de-oliveira-c-m-marques-and-k-kremer-soft-matter-2016-12-7995
#15
Andrea Pica, Giuseppe Graziano
In a recent article, Kremer and co-workers have combined NMR measurements and very long, all-atom MD simulations to strengthen their original claim that PNIPAM cononsolvency in water-methanol solutions is driven by the ability of MeOH molecules to bridge different monomers far away along the polymeric chain. In this comment, the results presented by Kremer and co-workers are reviewed, analyzed, and questioned regarding their ability to provide support to the bridging mechanism. Here, some pieces of evidence are provided to show that: (1) the solvent-excluded volume effect plays always a fundamental role in polymer collapse; (2) PNIPAM cononsolvency is caused by the geometric-energetic frustration experienced by the polymer when it can interact with both water and methanol molecules at the same time...
October 20, 2017: Soft Matter
https://www.readbyqxmd.com/read/29051794/electronic-structure-of-the-cu3-%C3%AE-o-3-2-cluster-in-mordenite-zeolite-and-its-effects-on-the-methane-to-methanol-oxidation
#16
Konstantinos D Vogiatzis, Guanna Li, Emiel J M Hensen, Laura Gagliardi, Evgeny A Pidko
Identifying Cu-exchanged zeolites able to activate C-H bonds and selectively convert methane to methanol is a challenge in the field of biomimetic heterogeneous catalysis. Recent experiments point to the importance of trinuclear [Cu3(μ-O)3](2+) complexes inside the micropores of mordenite (MOR) zeolite for selective oxo-functionalization of methane. The electronic structures of these species, namely, the oxidation state of Cu ions and the reactive character of the oxygen centers, are not yet fully understood...
October 12, 2017: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
https://www.readbyqxmd.com/read/29049977/syk-gtp-rac-1-mediated-immune-stimulatory-effect-of-cuscuta-epithymum-ipomoea-batata-and-euphorbia-hirta-plant-extracts
#17
Vanitha Sagar Sudam, Ajay Godwin Potnuri, N J Prameela Subhashini
Polymorphonuclear neutrophils (PMNn) are the pivotal mediators of phagocytosis. In addition to neutropenia, impaired neutrophilic function is associated with pathological conditions and immuno-deficiencies. Henceforth, Immuno-stimulatory strategies targeting neutrophilic function are indeed powerful tools in combating obstinate infections. In appreciation towards the usefulness of herbal medicines in therapeutic scenario, the present study was carried out to analyse the immuno-stimulatory effect of Cuscuta epithymum, Ipomoea batata and Euphorbia hirta using in-vitro and in-vivo rodent experimental models...
October 16, 2017: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
https://www.readbyqxmd.com/read/29049940/photocatalytic-degradation-of-synthetic-food-dye-sunset-yellow-fcf-fd-c-yellow-no-6-by-ailanthus-excelsa-roxb-possessing-antioxidant-and-cytotoxic-activity
#18
Subramanyam Deepika, Rajendran Harishkumar, Murugesan Dinesh, Rajadurai Abarna, Moorthy Anbalagan, Selvaraj Mohana Roopan, Chinnadurai Immanuel Selvaraj
The purpose of our work is to identify the bioactive compounds of bark and leaves extract from Ailanthus excelsa Roxb. and to explore its effectiveness against synthetic food dye. The presence of primary and secondary metabolites was confirmed by carrying out phytochemicals analysis. With the prior knowledge accessible on the indispensable secondary metabolites holding antioxidant and cytotoxicity activity, the quantitative screening of total phenolic and flavonoid content in methanolic and aqueous extract of bark and leaves from Ailanthus excelsa were done...
October 12, 2017: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/29048856/-rapid-determination-of-four-phenolic-environmental-estrogen-residues-in-cooking-oil-by-ultra-performance-liquid-chromatography-high-resolution-mass-spectrometry-coupled-with-solid-phase-extraction
#19
Shengdong Pan, Qian He, Xiaohong Chen, Li Wang, Qiaoli Qiu, Micong Jin
A fast, sensitive and accurate method for the determination of trace bisphenol S (BPS), bisphenol F (BPF), bisphenol A (BPA) and 4-nonylphenol (4-NP) in cooking oil samples was developed by ultra-performance liquid chromatography-high resolution mass spectrometry (UPLC-HRMS) coupled with solid-phase extraction (SPE). Cooking oil samples were extracted by acetonitrile, then the supernatant was purified by SLC SPE cartridges. The chromatographic separation was carried out on a Waters ACQUITY UPLC HSS T3 column (100 mm×2...
September 8, 2017: Se Pu, Chinese Journal of Chromatography
https://www.readbyqxmd.com/read/29048854/-determination-of-the-plant-growth-regulators-in-batatas-by-matrix-solid-phase-dispersive-extraction-and-high-performance-liquid-chromatography-with-tandem-mass-spectrometry
#20
Jing Zhang, Huihui Wan, Hua Zhang
An analytical method based on matrix solid-phase dispersive (MSPD) extraction and high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was established for the determination of forchlorfenuron, 6-benzylaminopurine (6-BA), N-(2-ethylhexyl)-5-norbornene-2,3-dicarboximide (MGK 264) and paclobutrazol in batatas. The samples were dispersed with silica by grinding, and then extracted with methanol. The determination was carried out on a Thermo hypersil GOLD C18 column (150 mm×2.1 mm, 5 μm) in gradient elution with mobile phases of methanol and ammonium formate (5 mmol/L, containing 0...
September 8, 2017: Se Pu, Chinese Journal of Chromatography
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