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https://www.readbyqxmd.com/read/29140981/wavelet-brain-angiography-suggests-arteriovenous-pulse-wave-phase-locking
#1
William E Butler
When a stroke volume of arterial blood arrives to the brain, the total blood volume in the bony cranium must remain constant as the proportions of arterial and venous blood vary, and by the end of the cardiac cycle an equivalent volume of venous blood must have been ejected. I hypothesize the brain to support this process by an extraluminally mediated exchange of information between its arterial and venous circulations. To test this I introduce wavelet angiography methods to resolve single moving vascular pulse waves (PWs) in the brain while simultaneously measuring brain pulse motion...
2017: PloS One
https://www.readbyqxmd.com/read/29140897/psychological-and-psychophysiological-effects-of-recuperative-music-postexercise
#2
Costas I Karageorghis, Andrew C Bruce, Suzanne T Pottratz, Rebecca C Stevens, Marcelo Bigliassi, Mark Hamer
PURPOSE: Few studies have examined the psychological and psychophysiological effects of recuperative music following exhaustive exercise. The main purpose of the present study was to examine the effects of two music conditions compared with a no-music control on psychological and psychophysiological recovery processes post-exercise. METHODS: A randomized, fully counterbalanced, crossover design was used. Core affect, salivary cortisol, heart rate, and blood pressure were measured before exhaustive exercise, immediately after, and in 10-, 20-, and 30-min intervals during passive recovery (21 women and 21 men; 20...
November 15, 2017: Medicine and Science in Sports and Exercise
https://www.readbyqxmd.com/read/29140426/development-and-validation-of-stereo-selective-method-for-the-separation-of-razoxane-enantiomers-in-hydrophilic-interaction-chromatography
#3
Ch Thirupathi, K Nagesh Kumar, G Srinivasu, Ch Lakshmi Narayana, Ch Parameswara Murthy
A novel sensitive and high throughput chiral hydrophilic interaction chromatographic (HILIC) method was developed to separate razoxane enantiomers namely levrazoxane (R-isomer) and dexrazoxane (DEX) in pharmaceutical active ingredient samples. A systematic chiral chromatographic screening system was employed in using multiple HPLC chromatographic modes on various polysaccharide based chiral columns to obtain a potential separation between enantiomers. HPLC separation was achieved using a mobile phase of aqueous 10 mM ammonium bicarbonate and mixture of organic modifiers (70/30, v/v) in the ratio of (5/95, v/v) on an immobilized polysaccharide based chiral stationary phase namely CHIRALPAK IE-3...
November 13, 2017: Journal of Chromatographic Science
https://www.readbyqxmd.com/read/29140331/multi-wavelength-filtering-with-a-waveguide-integrated-phase-modulated-bragg-grating
#4
Somnath Paul, Toni Saastamoinen, Seppo Honkanen, Matthieu Roussey, Markku Kuittinen
We present a multi-wavelength band-rejection filter on a titanium dioxide-coated silicon-on-insulator platform. The concept rests on the use of a finely tuned waveguide-based Bragg grating for which the periods are slightly varied from one to another. This phase-modulated Bragg grating enables precise customization of integrated waveguide filters. The number of rejection bands and the center-to-center separation between them are tailored by dividing the grating into several super-periods and coding an optimal phase function onto each super-period...
November 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/29140072/novel-aerosol-phase-extraction-method-for-the-determination-of-ca-k-mg-and-na-in-biodiesel-through-inductively-coupled-plasma-atomic-emission-spectrometry
#5
Raquel Sanchez, Salvador Maestre, Maria Soledad Prats Moya, José Luis Todoli
A novel extraction method was developed, optimized and validated for the elemental analysis of organic samples. The method, called aerosol phase extraction (APE), was based on the nebulization of the extracting aqueous solution (0.1 mol L-1 nitric acid) on the sample. The extraction was performed at the interface of each generated extractant droplets as they entered in contact with the samples. Afterwards, the phases were allowed to separate and Ca, K, Na and Mg were determined in aqueous phase by means of inductively coupled plasma optical emission spectroscopy (ICP-OES)...
November 15, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/29139609/development-of-a-high-throughput-method-based-on-thin-film-microextraction-using-a-96-well-plate-system-with-a-cork-coating-for-the-extraction-of-emerging-contaminants-in-river-water-samples
#6
Lucas Morés, Adriana Neves Dias, Eduardo Carasek
In this study, a new method was developed in which a biosorbent material is used as the extractor phase in conjunction with a recently described sample preparation technique called thin-film microextraction and a 96-well plate system. The method was applied to the determination of emerging contaminants, such as 3-(4-methylbenzylidene) camphor, ethylparaben, triclocarban and bisphenol A, in water samples. The separation and detection of the analytes were performed by high-performance liquid chromatography with diode array detection...
November 15, 2017: Journal of Separation Science
https://www.readbyqxmd.com/read/29139499/the-role-of-phase-separation-and-related-topography-in-the-exceptional-ice-nucleating-ability-of-alkali-feldspars
#7
Thomas F Whale, Mark A Holden, Alexander N Kulak, Yi-Yeoun Kim, Fiona C Meldrum, Hugo K Christenson, Benjamin J Murray
Our understanding of crystal nucleation is a limiting factor in many fields, not least in the atmospheric sciences. It was recently found that feldspar, a component of airborne desert dust, plays a dominant role in triggering ice formation in clouds, but the origin of this effect was unclear. By investigating the structure/property relationships of a wide range of feldspars, we demonstrate that alkali feldspars with certain microtextures, related to phase separation into Na and K-rich regions, show exceptional ice-nucleating abilities in supercooled water...
November 15, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29139174/neural-mechanisms-of-interference-control-in-working-memory-capacity
#8
Jessica Bomyea, Charles T Taylor, Andrea D Spadoni, Alan N Simmons
The extent to which one can use cognitive resources to keep information in working memory is known to rely on (1) active maintenance of target representations and (2) downregulation of interference from irrelevant representations. Neurobiologically, the global capacity of working memory is thought to depend on the prefrontal and parietal cortices; however, the neural mechanisms involved in controlling interference specifically in working memory capacity tasks remain understudied. In this study, 22 healthy participants completed a modified complex working memory capacity task (Reading Span) with trials of varying levels of interference control demands while undergoing functional MRI...
November 14, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/29138064/bicontinuous-microemulsions-as-a-biomembrane-mimetic-system-for-melittin
#9
Douglas G Hayes, Ran Ye, Rachel N Dunlap, Divina B Anunciado, Sai Venkatesh Pingali, Hugh M O'Neill, Volker S Urban
Antimicrobial peptides effectively kill antibiotic-resistant bacteria by forming pores in prokaryotes' biomembranes via penetration into the biomembranes' interior. Bicontinuous microemulsions, consisting of interdispersed oil and water nanodomains separated by flexible surfactant monolayers, are potentially valuable for hosting membrane-associated peptides and proteins due to their thermodynamic stability, optical transparency, low viscosity, and high interfacial area. Here, we show that bicontinuous microemulsions formed by negatively-charged surfactants are a robust biomembrane mimetic system for the antimicrobial peptide melittin...
November 11, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/29137712/hydrophilic-interaction-liquid-chromatography-of-hydroxy-aromatic-carboxylic-acid-positional-isomers
#10
Ashley E Richardson, Neil D Danielson
Hydrophilic interaction liquid chromatography (HILIC) has become increasingly popular as an alternative to reversed phase LC due to its ease of separating complex polar compound mixtures and the compatibility of the mobile phase with mass spectrometry (MS). Using a plain silica column (150  mm × 4.6  mm), we have shown a mixture containing three hydroxybenzoic acid isomers plus syringic and vanillic acid and three hydroxycinnamic acid isomers plus ferulic and sinapic acid can be separated using a mobile phase comprised of 90% acetonitrile (MeCN) and 10% 20 mM ammonium acetate at pH 6 in under 45 min...
December 15, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/29136927/enantioselective-determination-of-metconazole-in-multi-matrices-by-high-performance-liquid-chromatography
#11
Rujian He, Jun Fan, Qi Tan, Yecai Lai, Xiaodong Chen, Tai Wang, Ying Jiang, Yaomou Zhang, Weiguang Zhang
A reliable and effective HPLC analytical method has been developed to stereoselectively quantify metconazole in soil and flour matrices. Effects of polysaccharide chiral stationary phase, type and content of alcoholic modifier on separation of racemic metconazole have been discussed in detail. Resolution and quantitative determination of metconazole stereoisomers were performed by using an Enantiopak OD column, with the n-hexane-ethanol mixture (97:3, v/v) at the flow rate of 1.0mL/min. Then, extraction and cleanup procedures followed by the modified QuEChERS (quick, easy, cheap, effective, rugged and safe) method were used for metconazole racemate in soil and flour matrices...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29136876/capillary-electrochromatography-using-knitted-aromatic-polymer-as-the-stationary-phase-for-the-separation-of-small-biomolecules-and-drugs
#12
Pingxiu Tang, Zilin Chen
Hypercrosslinked polymers (HCPs) are currently receiving great attention due to their unique characteristics and potential uses in diverse areas. However, the field of HCPs for open-tubular capillary electrochromatography (OT-CEC) separations has not been explored. Here, a knitted aromatic polymer (KAP) was in-situ grown on the inner wall of the capillary column for OT-CEC for the first time. The silylating reagent containing phenyl was served as monomer, immobilized on the inner wall of the capillary column, and then KAPs-modified capillary column was prepared through in-situ hypercrosslinking reaction...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29136864/suspect-screening-of-halogenated-carboxylic-acids-in-drinking-water-using-ion-exchange-chromatography-high-resolution-orbitrap-mass-spectrometry-ic-hrms
#13
Matteo D Gallidabino, Laurence Hamdan, Bronagh Murphy, Leon P Barron
Retrospective in silico screening of analytical data for the identification of new or emerging disinfection by-products in drinking waters could be useful to assess quality and potential hazards, as well as help implement mitigation procedures more rapidly. Herein, the first study coupling ion exchange chromatography (IC) with high resolution mass spectrometry (HRMS) for the determination of halogenated carboxylic acid disinfectant by-products is reported. Separation was achieved using a Metrohm A Supp 5 column and a Na2CO3/NaHCO3 gradient eluent from 1/0...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29136861/quality-by-design-approach-in-the-development-of-an-ultra-high-performance-liquid-chromatography-method-for-bexsero-meningococcal-group-b-vaccine
#14
Luca Nompari, Serena Orlandini, Benedetta Pasquini, Cristiana Campa, Michele Rovini, Massimo Del Bubba, Sandra Furlanetto
Bexsero is the first approved vaccine for active immunization of individuals from 2 months of age and older to prevent invasive disease caused by Neisseria meningitidis serogroup B. The active components of the vaccine are Neisseria Heparin Binding Antigen, factor H binding protein, Neisseria adhesin A, produced in Escherichia coli cells by recombinant DNA technology, and Outer Membrane Vesicles (expressing Porin A and Porin B), produced by fermentation of Neisseria meningitidis strain NZ98/254. All the Bexsero active components are adsorbed on aluminum hydroxide and the unadsorbed antigens content is a product critical quality attribute...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29136854/disperse-magnetic-solid-phase-microextraction-and-surface-enhanced-raman-scattering-dis-mspme-sers-for-the-rapid-detection-of-trace-illegally-chemicals
#15
Shihua Yu, Zhigang Liu, Weixian Wang, Li Jin, Weiqing Xu, Yuqing Wu
The technique of solid phase micro-extraction (SPME) is an important method for sample pretreatment in analytical chemistry, especially for the analysis in micro-systems. Surface enhanced Raman scattering (SERS) is an ultra-sensitive and fast detection technique. Both are particularly important in qualitative analysis of trace amount of substance. In this study, combining the magnetic nanoparticles with magnetic SPME device, we develop a high efficient new pretreatment method named as disperse magnetic solid phase micro-extraction (Dis-MSPME)...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29136849/simultaneous-determination-of-three-estrogens-in-human-saliva-without-derivatization-or-liquid-liquid-extraction-for-routine-testing-via-miniaturized-solid-phase-extraction-with-lc-ms-ms-detection
#16
Xiaoguang Sunny Li, Shu Li, Gottfried Kellermann
Accurate quantitation of estrogens (i.e, estrone (E1), estradiol (E2) and estriol (E3)) is valuable for clinical assessment of human health and disease. Alterations in estrogen levels have been implicated in numerous pathological conditions. However, inadequacies in sensitivity and specificity, cumbersome sample preparation and invasive specimen collection hamper the usability of available methods for clinical applications. Herein, a simple, rapid, highly sensitive and specific LC-MS/MS method was developed and validated for the simultaneous determination of three estrogens in human saliva providing a non-invasive alternative to conventional blood samples...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29136831/rapid-method-for-determination-of-90-sr-in-seawater-by-liquid-scintillation-counting-with-an-extractive-scintillator
#17
Masaki Uesugi, Ryosuke Watanabe, Hiroaki Sakai, Akihiko Yokoyama
A rapid determination method of (90)Sr is developed for the monitoring of seawater around the Fukushima Daiichi Nuclear Power Plant (FDNPP). Three ideas of chemical separation and measurements to accelerate (90)Sr analysis are investigated. Strontium is co-precipitated in a two-step procedure with hydroxyapatite after the removal of magnesium phosphate in the presence of citric acid. The purification process of strontium is in combination with solid phase extraction disks. One or two sheets of Sr Rad disk and cyclic operations are examined to eliminate interfering substances and secure the exchange capacity...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29136814/polyaniline-dicationic-ionic-liquid-coated-with-magnetic-nanoparticles-composite-for-magnetic-solid-phase-extraction-of-polycyclic-aromatic-hydrocarbons-in-environmental-samples
#18
Mohamad Shariff Shahriman, Muggundha Raoov Ramachandran, Nur Nadhirah Mohamad Zain, Sharifah Mohamad, Ninie Suhana Abdul Manan, Suhaila Mohd Yaman
In this present study, magnetic nanoparticles (MNPs) nanocomposites modified with polyaniline (PANI) coated newly synthesised dicationic ionic liquid (DICAT) forming MNP-PANI-DICAT were successfully synthesised as new generation material for magnetic solid phase extraction (MSPE). MNP-PANI-DICAT was characterised by FT-IR NMR, CHN, BET, SEM, TEM, and VSM techniques and the results were compared with MNP-PANI and native MNP. This new material was applied as a magnetic adsorbent for the pre-concentration and separation of polycyclic aromatic hydrocarbons (PAHs) due to the π-π interaction between polyaniline shell and dicationic ionic liquid (DICAT) with PAHs compounds...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29136812/silica-based-click-dibenzo-18-crown-6-ether-high-performance-liquid-chromatography-stationary-phase-and-its-application-in-separation-of-fullerenes
#19
Yanzhe Li, Zhe Sheng, Chuanlei Zhu, Wei Yin, Changhu Chu
Crown ether is a type of typical macrocyclic polyether compounds, which can produce strong interactions with cationic species, such as metal ions and protonated amines due to its cavity structure and the strong electronegative effect of heteroatoms on the crown ether ring. In this paper, a type of silica based crown ether stationary phase was prepared by covalently bonding dibenzo-18-crown 6-ether (DBCE) on silica gel via copper (I) catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC). The tetraazido DBCE was rapidly prepared by bromomethylation and subsequent azido substitution of DBCE...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29136796/a-multi-purpose-tool-for-food-inspection-simultaneous-determination-of-various-classes-of-preservatives-and-biogenic-amines-in-meat-and-fish-products-by-lc-ms
#20
Luciano Molognoni, Heitor Daguer, Leandro Antunes de Sá Ploêncio, Juliano De Dea Lindner
This paper describes an innovative fast and multipurpose method for the chemical inspection of meat and fish products by liquid chromatography-tandem mass spectrometry. Solid-liquid extraction and low temperature partitioning were applied to 17 analytes, which included large bacteriocins (3.5kDa) and small molecules (organic acids, heterocyclic compounds, polyene macrolides, alkyl esters of the p-hydroxybenzoic acid, aromatic, and aliphatic biogenic amines and polyamines). Chromatographic separation was achieved in 10min, using stationary phase of di-isopropyl-3-aminopropyl silane bound to hydroxylated silica...
February 1, 2018: Talanta
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