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https://www.readbyqxmd.com/read/28738640/new-insights-in-forensic-chemistry-nir-chemometrics-analysis-of-toners-for-questioned-documents-examination
#1
Stefano Materazzi, Roberta Risoluti, Sara Pinci, Francesco Saverio Romolo
Near-Infrared spectroscopy (NIRs) coupled to chemometrics was investigated for the first time as a new tool for the analysis of black toners to evaluate its application in forensic cases. Ten black toners from four manufacturers were included in this study and the acquired spectra were compared in order to differentiate toners. Multivariate statistical analysis based on Principal Component Analysis (PCA) was considered to develop a model of comparison of toners in questioned documents. Results demonstrated the capabilities of the approach NIR/Chemometrics to correctly identify toners when printed on different papers and to be not affected by the printing process...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738622/a-flow-based-procedure-exploiting-the-lab-in-syringe-approach-for-the-determination-of-ester-content-in-biodiesel-and-diesel-biodiesel-blends
#2
Samara Soares, Wanessa R Melchert, Fábio R P Rocha
The ester content is an important parameter to be monitored in biodiesel for evaluation of the transesterification reaction yield and for assessing the purity of the final product. This is also a relevant quality parameter in diesel/biodiesel blends to avoid frauds, because legislation establishes a minimum amount of biodiesel to be added to diesel. The official method EN14103 requires the addition of an alternative internal standard (methyl nonadecanoate) for analysis of biodiesel from bovine tallow because the methyl heptadecanoate is found in high amounts in this product...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738615/electrochemical-magneto-immunosensor-based-on-endogenous-%C3%AE-galactosidase-enzyme-to-determine-enterotoxicogenic-escherichia-coli-f4-k88-in-swine-feces-using-square-wave-voltammetry
#3
Lorena Viviana Tarditto, María Alicia Zon, Hugo García Ovando, Nelio Roberto Vettorazzi, Fernando Javier Arévalo, Héctor Fernández
Diseases caused by enterotoxicogenic Escherichia coli F4 (K88) (ETEC F4) are a problem in swine production establishments. Due to the high rate of mortality and morbidity of E. coli infections, a rapid and accurate diagnosis is important in order to choose an appropriate treatment to reduce the economic impact. Therefore, an electrochemical magneto-immunosensor (EMI) was developed to detect and quantify ETEC F4 in swine feces samples through a direct non-competitive immunoassay. ETEC F4 was selectively captured by immunomagnetic separation...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738608/a-fast-bioanalytical-method-based-on-microextraction-by-packed-sorbent-and-uplc-ms-ms-for-determining-new-psychoactive-substances-in-oral-fluid
#4
A M Ares, P Fernández, M Regenjo, A M Fernández, A M Carro, R A Lorenzo
The emergence in recent years of potentially dangerous new psychoactive substances (NPS) that are not under international control has led to the development of multi-analyte procedures for their unequivocal quantification. A fast ultra-performance liquid chromatography-tandem mass spectrometry method (UPLC-MS/MS), in combination with a sample pretreatment based on microextraction by packed sorbent (MEPS), was for the first time used in this work for the simultaneous determination of NPS in oral fluid. This matrix is an effective alternative to typical biological samples for drug control in substitution therapy programs, and also for the prevention and reduction of traffic accidents...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738602/portable-electrochemical-system-using-screen-printed-electrodes-for-monitoring-corrosion-inhibitors
#5
André L Squissato, Weberson P Silva, Augusto T S Del Claro, Diego P Rocha, Rafael M Dornellas, Eduardo M Richter, Christopher W Foster, Craig E Banks, Rodrigo A A Munoz
This work presents a portable electrochemical system for the continuous monitoring of corrosion inhibitors in a wide range of matrices including ethanol, seawater and mineral oil following simple dilution of the samples. Proof-of-concept is demonstrated for the sensing of 2,5-dimercapto-1,3,5-thiadiazole (DMCT), an important corrosion inhibitor. Disposable screen-printed graphitic electrodes (SPGEs) associated with a portable batch-injection cell are proposed for the amperometric determination of DMCT following sample dilution with electrolyte (95% v/v ethanol + 5% v/v 0...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738594/optical-sensor-for-fluoride-determination-in-tea-sample-based-on-evanescent-wave-interaction-and-fiber-optic-integration
#6
Yan Xiong, Jiayi Wu, Qing Wang, Jing Xu, Shenwen Fang, Jie Chen, Ming Duan
In this work, a miniaturized optical sensor was developed for fluoride determination in tea samples to evaluate their specific risks of fluorosis for public health based on evanescent-wave interaction. The sensor design was integrated on the optical fiber by utilizing the evanescent wave produced on the fiber surface to react with sensing reagents. According to the absorption change at 575nm, fluoride could be determined by colorimetric method and evaluated by Beer's law. With improved performances of small detection volume (1...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738578/a-simple-method-for-the-multi-elemental-analysis-of-beer-using-total-reflection-x-ray-fluorescence
#7
Ednilton M Gama, Clésia C Nascentes, Roberta P Matos, Gabrielle de C Rodrigues, Guilherme D Rodrigues
A method of direct analysis for quantification of 15 inorganic elements (P, S, Cl, K, Ca, Mn, Fe, Ni, Cu, Zn, Br, As, Rb, Sr and Pb) in beers by Total Reflection X-Ray Fluorescence (TXRF) was developed. The experimental conditions were optimized. Direct analysis was compared with the acid digestion procedure to evaluate the effect matrix and the results were satisfactory. The evaluation of the accuracy and precision was realized by analysis of two certified reference materials of natural and waste water. For the majority of the elements, good agreement was achieved between the certified value and the value measured in the CRM´s...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738563/urinary-volatile-fingerprint-based-on-mass-spectrometry-for-the-discrimination-of-patients-with-lung-cancer-and-controls
#8
Álvaro García Ramos, Ana Pérez Antón, Miguel Del Nogal Sánchez, José Luis Pérez Pavón, Bernardo Moreno Cordero
Profile signals of urine samples corresponding to patients with lung cancer and controls were obtained using a non-separative methodology. The method is based on the coupling of a headspace sampler, a programed temperature vaporizer and a mass spectrometer (HS-PTV-MS). With only a centrifugation step as prior sample treatment, the samples were subjected to the headspace generation process and the volatiles generated were introduced into the PTV where they were trapped in the Tenax® packed liner while the solvent was purged...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738520/dissolving-microneedles-for-transdermal-drug-delivery-advances-and-challenges
#9
REVIEW
Kevin Ita
Over the last number of years, a significant body of evidence has shown the benefit of using dissolving microneedles (DMNs) for transdermal drug delivery. These devices are prepared from a wide range of materials such as sugars and polymers. DMNs are mainly fabricated by micromolding, photopolymerization, drawing lithography and droplet-airborne blowing. In this review, we have focused on the advances made in the field in recent years using a representative set of studies. Although the list of studies is not exhaustive, they highlight the challenges encountered such as the need to increase mechanical strength as well as medication dose while ensuring fast release of the active ingredient...
July 19, 2017: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
https://www.readbyqxmd.com/read/28738506/taxonomy-or-trait-based-ecological-assessment-for-tropical-rivers-case-study-on-benthic-diatoms-in-mayotte-island-france-indian-ocean
#10
Kálmán Tapolczai, Agnès Bouchez, Csilla Stenger-Kovács, Judit Padisák, Frédéric Rimet
Diatom-based ecological quality assessment methods have been implemented and used regularly in the Water Framework Directive. These indices use the species' abundance profiles along a specific environmental gradient, which they aim to assess. However, this approach has several problematic issues including the unstable and fast-changing diatom taxonomy. The use of traits can be a solution if their responses to the environmental pressure are well-defined. Here, we developed taxonomy-based and trait-based diatom assemblage indices to assess the ecological status of riverine sites on a tropical island...
July 18, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28738305/contamination-characteristics-and-source-apportionment-of-methylated-pahs-in-agricultural-soils-from-yangtze-river-delta-china
#11
Weixiao Chen, Xinyi Wu, Haiyun Zhang, Jianteng Sun, Wenxin Liu, Lizhong Zhu, Xiangdong Li, Daniel C W Tsang, Shu Tao, Xilong Wang
Alkylated PAHs (APAHs) have been shown to be more toxic and persistent than their non-alkylated parent compounds. However, little is known about the extent of soil contamination by these pollutants. To help understand agricultural soil pollution by these compounds at a regional scale, a total of 18 methylated PAHs (MPAHs, a major class of APAHs) in 243 soil samples were analyzed. These soil samples were collected from 11 sites in the Yangtze River Delta (YRD) region, a representative fast developing area in China...
July 21, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28738281/edta-functionalized-fe3o4-graphene-oxide-for-efficient-removal-of-u-vi-from-aqueous-solutions
#12
Donglin Zhao, Qi Zhang, Han Xuan, Yan Chen, Kehua Zhang, Shaojie Feng, Ahmed Alsaedi, Tasawar Hayat, Changlun Chen
In this study, a regenerable magnetic ligand material (EDTA-mGO) was fabricated by binding chelating groups (EDTA) onto Fe3O4/graphene oxide and applied to remove U(VI) from aqueous solution. The sorption experiments were investigated under different experimental conditions, such as temperature, contact time and pH. EDTA-mGO showed fast removal capacity for U(VI) (<1.5h) with high sorption ability (277.43mg/g). The removal mechanisms mainly attributed to the metal-binding organic ligand (EDTA) and the electrostatic attractions between U(VI) and oxygenic functional groups...
July 17, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28737942/the-role-of-rydberg-valence-coupling-in-the-ultrafast-relaxation-dynamics-of-acetone
#13
Markus Koch, Bernhard Thaler, Pascal Heim, Wolfgang E Ernst
The electronic structure of excited states of acetone is represented by a Rydberg manifold that is coupled to valence states which provide very fast and efficient relaxation pathways. We observe and characterize the transfer of population from photoexcited Rydberg states (6p, 6d, 7s) to a whole series of lower Rydberg states (3p to 4d) and a simultaneous decay of population from these states. We obtain these results with time-resolved photoelectron-photoion coincidence (PEPICO) detection in combination with the application of Bayesian statistics for data analysis...
July 24, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28737892/automated-in-situ-measurement-of-gas-solubility-in-liquids-with-a-simple-tube-in-tube-reactor
#14
Jiisong Zhang, Andrew R Teixeira, Haomiao Zhang, Klavs F Jensen
Gas solubility data in liquids are foundational for assessing a variety of multiphase separations and gas-liquid reactions. Taking advantage of the Tube-in-Tube reactor design built with the semi-permeable Teflon AF-2400 tubes, the liquids are rapidly saturated without direct contacting of gas and liquid. The gas solubility can be determined by performing a steady-state flux balance of both gas and liquid flowing into the reactor system. With this reactor, a fully automated strategy is developed for fast in situ measurement of gas solubility in liquids...
July 24, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28737819/insertion-reactions-of-small-unsaturated-molecules-in-the-n-b-bonds-of-boron-guanidinates
#15
Alberto Ramos, Antonio Antiñolo, Fernando Carrillo-Hermosilla, Rafael Fernández-Galán, María Del Pilar Montero-Rama, Elena Villaseñor, Antonio Rodríguez-Diéguez, Daniel García-Vivó
We report here 1,1- and 1,2-insertion reactions of small unsaturated molecules in the N-B bonds of two boron guanidinates, (Me2N)C(N(i)Pr)2BCy2 (1) and {(i)Pr(H)N}C(N(i)Pr){N(p-(t)Bu-C6H4)}BCy2 (2), and two bisboron guanidinates(2-), {(i)Pr(BCy2)N}C(N(i)Pr){N(p-(t)Bu-C6H4)}BCy2 (3) and {(i)Pr(C8H14B)N}C(N(i)Pr){N(p-Me-C6H4)}BC8H14 (4), the latter being prepared for the first time by double deprotonation of the corresponding guanidine with the 9-borabicyclo[3.3.1]nonane dimer, (H-BC8H14)2. Compounds 1-4 easily insert aromatic isonitriles, XylNC (Xyl = 2,6-Me2-C6H3) and (p-MeO-C6H4)NC, to give the expected diazaboroles 5-12, some of them being structurally characterised by X-ray diffraction...
July 24, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28737747/a-spatially-localized-architecture-for-fast-and-modular-dna-computing
#16
Gourab Chatterjee, Neil Dalchau, Richard A Muscat, Andrew Phillips, Georg Seelig
Cells use spatial constraints to control and accelerate the flow of information in enzyme cascades and signalling networks. Synthetic silicon-based circuitry similarly relies on spatial constraints to process information. Here, we show that spatial organization can be a similarly powerful design principle for overcoming limitations of speed and modularity in engineered molecular circuits. We create logic gates and signal transmission lines by spatially arranging reactive DNA hairpins on a DNA origami. Signal propagation is demonstrated across transmission lines of different lengths and orientations and logic gates are modularly combined into circuits that establish the universality of our approach...
July 24, 2017: Nature Nanotechnology
https://www.readbyqxmd.com/read/28737574/is-there-a-role-for-enterohormones-in-the-gastroparesis-of-critically-ill-patients
#17
Carlos A Santacruz, Amanda Quintairos, Claudia Righy, Ilaria A Crippa, Lucio Couto, Virginie Imbault, Mongkolpun Wasineeart, Mathieu De Ryckere, Jean-Charles Preiser
OBJECTIVES: Delayed gastric emptying occurs in critically ill patients and impairs the delivery, digestion, and absorption of enteral feeding. A pathophysiologic role of the enterohormones peptide YY and ghrelin is supported by preclinical data. To compare the circulating plasma levels of peptide YY and ghrelin in control subjects and in critically ill patients, during feeding and fasting, and to search for a correlation with gastric emptying. DESIGN: A prospective observational trial...
July 21, 2017: Critical Care Medicine
https://www.readbyqxmd.com/read/28737528/genetic-variants-of-increased-waist-circumference-in-psychosis
#18
Dzana S Hukic, Urban Ösby, Eric Olsson, Agneta Hilding, Claes-Göran Östenson, Harvest F Gu, Ewa Ehrenborg, Gunnar Edman, Martin Schalling, Catharina Lavebratt, Louise Frisén
OBJECTIVE: We examined whether established metabolic risk genetic variants in the population confer a risk for increased waist circumference in patients with schizophrenia spectrum disorders and also an association with schizophrenia spectrum disorders irrespective of waist circumference. PATIENTS AND METHODS: We analyzed the association in (i) a case-case model in which patients with schizophrenia spectrum disorder with increased waist circumference (≥80 cm for women and ≥94 cm for men) (n=534) were compared with patients with normal waist circumference (<80 cm for women; <94 cm for men) (n=124), and in (ii) a case-control model in which schizophrenia spectrum disorder patients with increased waist circumference or irrespective of waist circumference were compared with population-derived controls (n=494) adjusted for age, sex, fasting glucose, smoking, and family history of diabetes...
July 21, 2017: Psychiatric Genetics
https://www.readbyqxmd.com/read/28737409/low-buffer-capacity-and-alternating-motility-along-the-human-gastrointestinal-tract-implications-for-in-vivo-dissolution-and-absorption-of-ionizable-drugs
#19
Bart Hens, Yasuhiro Tsume, Marival Bermejo, Paulo Paixao, Mark Koenigsknecht, Jason R Baker, William L Hasler, R Lionberger, Jianghong Fan, Joseph Dickens, Kerby A Shedden, Bo Wen, Jeffrey Wysocki, Raimar Löbenberg, Allen Lee, Ann F Fioritto, Gregory E Amidon, Alex Yu, Gail Benninghoff, Niloufar Salehi, Arjang Talattof, Duxin Sun, Gordon L Amidon
In this study, we determined the pH and buffer capacity of human gastrointestinal (GI) fluids (aspirated from the stomach, duodenum, proximal jejunum and mid/distal jejunum) as a function of time, from 37 healthy subjects after oral administration of an 800 mg immediate-release tablet of ibuprofen (reference listed drug; RLD) under typical prescribed bioequivalence (BE) study protocol conditions in both fasted and fed state (simulated by ingestion of a liquid meal). Simultaneously, motility was continuously monitored using water-perfused manometry...
July 24, 2017: Molecular Pharmaceutics
https://www.readbyqxmd.com/read/28737398/in-vivo-mechanisms-of-intestinal-drug-absorption-from-aprepitant-nanoformulations
#20
Carl Roos, David Dahlgren, Staffan Berg, Jan Westergren, Bertil Abrahamsson, Christer Tannergren, E Sjögren, H Lennernas
Over recent decades there has been an increase in the proportion of BCS class II and IV drug candidates in industrial drug development. To overcome the biopharmaceutical challenges associated with the less favorable properties of solubility and/or intestinal permeation of these substances, the development of formulations containing nanosuspensions of the drugs has been suggested. The intestinal absorption of aprepitant from two nanosuspensions (20 µM and 200 µM total concentrations) in phosphate buffer, one nanosuspension (200 µM) in fasted-state simulated intestinal fluid (FaSSIF), and one solution (20 µM) in FaSSIF was investigated in the rat single-pass intestinal perfusion model...
July 24, 2017: Molecular Pharmaceutics
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