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Analytical chemistry

Eliane Gandolpho Tótoli, Hérida Regina Nunes Salgado
Bacterial conjunctivitis has high impact on the health of the population, since it represents more than a third of ocular pathologies reported by health services worldwide. There is a high incidence of bacterial resistance to the antimicrobials most commonly used for the treatment of conjunctivitis. In this context, besifloxacin stands out, since it is a fluoroquinolone developed exclusively for topical ophthalmic use, presenting a low risk of developing resistance due to its reduced systemic exposure. Bausch & Lomb markets it as ophthalmic suspension, under the trade name Besivance™...
January 18, 2018: Critical Reviews in Analytical Chemistry
Shihua Yu, Zhigang Liu, Hongwei Li, Jianpo Zhang, Xin-Xin Yuan, Xiangyu Jia, Yuqing Wu
Surface enhanced Raman scattering (SERS) is an ultra-sensitive spectroscopy technique, which can provide rich structural information for a great number of molecules, while solid phase micro-extraction (SPME) is an efficient method for sample pretreatment in analytical chemistry, particularly in a micro-system. In the present report, a silver-loaded and graphene-based magnetic composite (Fe3O4@GO@Ag) was fabricated for use as both a SERS-active substrate and SPME material. The π-π stacking and fluorescence quenching abilities of GO make the composite a perfect candidate for SERS in analyzing real-world samples...
January 18, 2018: Analyst
Alan H B Wu, Robert H Christenson, Dina N Greene, Allan S Jaffe, Peter A Kavsak, Jordi Ordonez-Llanos, Fred S Apple
This document is an essential companion to the third iteration of the National Academy of Clinical Biochemistry [NACB,8 now the American Association for Clinical Chemistry (AACC) Academy] Laboratory Medicine Practice Guidelines (LMPG) on cardiac markers. The expert consensus recommendations were drafted in collaboration with the International Federation of Clinical Chemistry and Laboratory Medicine Task Force on Clinical Applications of Bio-Markers (IFCC TF-CB). We determined that there is sufficient clinical guidance on the use of cardiac troponin (cTn) testing from clinical practice groups...
January 17, 2018: Clinical Chemistry
Rob T P Jansen, Christa M Cobbaert, Cas Weykamp, Marc Thelen
Calibration 2.000 was initiated 20 years ago for standardization and harmonization of medical tests. The program also intended to evaluate adequate implementation of the In Vitro Diagnostics (IVD) 98/79/EC directive, in order to ensure that medical tests are fit-for-clinical purpose. The Calibration 2.000 initiative led to ongoing verification of test standardization and harmonization in the Netherlands using commutable external quality assessment (EQA)-tools and a type 1 EQA-design, where feasible. National support was guaranteed by involving all laboratory professionals as well as laboratory technicians responsible for EQA and quality officers...
January 17, 2018: Clinical Chemistry and Laboratory Medicine: CCLM
Devin A Hudson, Jeffrey L Caplan, Colin Thorpe
The development of genetically encoded fluorescent probes for analyte-specific imaging has revolutionized our understanding of intracellular processes. Current classes of intracellular probes depend on the selection of binding domains that either undergo conformational changes on analyte binding or can be linked to thiol redox chemistry. Here we have designed novel probes by fusing a flavoenzyme, whose fluorescence is quenched on reduction by the analyte of interest, with a GFP domain to allow for rapid and specific ratiometric sensing...
January 17, 2018: Biochemistry
Laurie J Points, James Ward Taylor, Jonathan Grizou, Kevin Donkers, Leroy Cronin
Protocell models are used to investigate how cells might have first assembled on Earth. Some, like oil-in-water droplets, can be seemingly simple models, while able to exhibit complex and unpredictable behaviors. How such simple oil-in-water systems can come together to yield complex and life-like behaviors remains a key question. Herein, we illustrate how the combination of automated experimentation and image processing, physicochemical analysis, and machine learning allows significant advances to be made in understanding the driving forces behind oil-in-water droplet behaviors...
January 16, 2018: Proceedings of the National Academy of Sciences of the United States of America
S Tuck, A Furey, S R H Crooks, M Danaher
Pyrethrin and pyrethroid pesticides are commonly used in crop protection and animal health, to control pests. As a result, they can potentially transfer into food if good agricultural practice is not followed or even due to accidental contamination. The analysis of these compounds has been widely reported in crops and the environment. However, the analysis of pyrethrin and pyrethroids has not been reported frequently in foods of animal origin, particularly animal tissues. The focus of this review is to report on pyrethrin and pyrethroid analysis including key aspects such as chemistry, choice of target matrix, sample preparation, chemical analysis, legislation and method validation...
January 16, 2018: Food Additives & Contaminants. Part A, Chemistry, Analysis, Control, Exposure & Risk Assessment
G Wille, C Lerouge, U Schmidt
In cassiterite, tin is associated with metals (titanium, niobium, tantalum, indium, tungsten, iron, manganese, mercury). Knowledge of mineral chemistry and trace-element distribution is essential for: the understanding of ore formation, the exploration phase, the feasibility of ore treatment, and disposal/treatment of tailings after the exploitation phase. However, the availability of analytical methods make these characterisations difficult. We present a multitechnical approach to chemical and structural data that includes scanning electron microscopy (SEM)-based imaging and microanalysis techniques such as: secondary and backscattered electrons, cathodoluminescence (CL), electron probe microanalyser (EPMA), electron backscattered diffraction (EBSD) and confocal Raman-imaging integrated in a SEM (RISE)...
January 16, 2018: Journal of Microscopy
Ashish Tiwari, S J Dhoble
Chemiluminescence (CL) techniques are extensively utilized for detection of analytes due to their high sensitivity, rapidity and selectivity. With the advent of nanotechnology and incorporation of the nanoparticles in the CL system has revolutionized the assays due to their unique optical and mechanical properties. Several CL-based reactions have been developed where these nanoparticle based CL sensors have evolved as excellent prospects for sensing in various analytical applications. This review article addresses the nanoparticles based CL detection system that are recently developed, the mechanisms has been summarized and the role of luminophors have been discussed...
April 1, 2018: Talanta
Ren-Hao Fan, Dong Liu, Ru-Wen Peng, Wen-Bo Shi, Hao Jing, Xian-Rong Huang, Mu Wang
In this work, we demonstrate broadband integrated polarization rotator (IPR) with a series of three-layer rotating metallic grating structures. This transmissive optical IPR can conveniently rotate the polarization of linearly polarized light to any desired directions at different spatial locations with high conversion efficiency, which is nearly constant for different rotation angles. The linear polarization rotation originates from multi-wave interference in the three-layer grating structure. We anticipate that this type of IPR will find wide applications in analytical chemistry, biology, communication technology, imaging, etc...
January 8, 2018: Optics Express
Manon Auffret, Sophie Drapier, Marc Vérin
The present paper consists of a comprehensive review of the literature on apomorphine pharmacological properties and its usefulness in Parkinson's disease (PD). The chemistry, structure-activity relationship, pharmacokinetics and pharmacodynamics of apomorphine are described with regard to its effects on PD symptoms, drug interactions, interindividual variability and adverse events. Apomorphine chemical structure accounts for most of its beneficial and deleterious properties, both dopaminergic and non-dopaminergic...
January 11, 2018: Clinical Drug Investigation
A A Heller, S Y Lockwood, T M Janes, D M Spence
The creation of a pharmacokinetic (PK) curve, which follows the plasma concentration of an administered drug as a function of time, is a critical aspect of the drug development process and includes such information as the drug's bioavailability, clearance, and elimination half-life. Prior to a drug of interest gaining clearance for use in human clinical trials, research is performed during the preclinical stages to establish drug safety and dosing metrics from data obtained from the PK studies. Both in vivo animal models and in vitro platforms have limitations in predicting human reaction to a drug due to differences in species and associated simplifications, respectively...
January 11, 2018: Annual Review of Analytical Chemistry
Sharon E Ashbrook, John M Griffin, Karen E Johnston
The sensitivity of nuclear magnetic resonance (NMR) spectroscopy to the local atomic-scale environment offers great potential for the characterization of a diverse range of solid materials. Despite offering more information than its solution-state counterpart, solid-state NMR has not yet achieved a similar level of recognition, owing to the anisotropic interactions that broaden the spectral lines and hinder the extraction of structural information. Here, we describe the methods available to improve the resolution of solid-state NMR spectra and the continuing research in this area...
January 11, 2018: Annual Review of Analytical Chemistry
Paul L A Popelier
Atomic multipole moments associated with a spherical volume fully residing within a topological atom (i.e., the β sphere) can be obtained analytically. Such an integration is thus free of quadrature grids. A general formula for an arbitrary rank spherical harmonic multipole moment is derived, for an electron density comprising Gaussian primitives of arbitrary angular momentum. The closed expressions derived here are also sufficient to calculate the electrostatic potential, the two types of kinetic energy, as well as the potential energy between atoms...
January 10, 2018: Journal of Computational Chemistry
Changyi Li, Stephen M Meckler, Zachary P Smith, Jonathan E Bachman, Lorenzo Maserati, Jeffrey R Long, Brett A Helms
Many forward-looking clean-energy technologies hinge on the development of scalable and efficient membrane-based separations. Ongoing investment in the basic research of microporous materials is beginning to pay dividends in membrane technology maturation. Specifically, improvements in membrane selectivity, permeability, and durability are being leveraged for more efficient carbon capture, desalination, and energy storage, and the market adoption of membranes in those areas appears to be on the horizon. Herein, an overview of the microporous materials chemistry driving advanced membrane development, the clean-energy separations employing them, and the theoretical underpinnings tying membrane performance to membrane structure across multiple length scales is provided...
January 8, 2018: Advanced Materials
Nora Nikolac Gabaj, Marijana Miler, Alen Vrtarić, Marina Hemar, Petra Filipi, Marija Kocijančić, Vesna Šupak Smolčić, Ivana Ćelap, Ana-Maria Šimundić
BACKGROUND: The aim of our study was to perform verification of serum indices on three clinical chemistry platforms. METHODS: This study was done on three analyzers: Abbott Architect c8000, Beckman Coulter AU5800 (BC) and Roche Cobas 6000 c501. The following analytical specifications were verified: precision (two patient samples), accuracy (sample with the highest concentration of interferent was serially diluted and measured values compared to theoretical values), comparability (120 patients samples) and cross reactivity (samples with increasing concentrations of interferent were divided in two aliquots and remaining interferents were added in each aliquot...
January 9, 2018: Clinical Chemistry and Laboratory Medicine: CCLM
Ronald J Midura, Valbona Cali, Mark E Lauer, Anthony Calabro, Vincent C Hascall
Hyaluronan (HA) exhibits numerous important roles in physiology and pathologies, and these facts necessitate an ability to accurately and reproducibly measure its quantities in tissues and cell cultures. Our group previously reported a rigorous and analytical procedure to quantify HA (and chondroitin sulfate, CS) using a reductive amination chemistry and separation of the fluorophore-conjugated, unsaturated disaccharides unique to HA and CS on high concentration acrylamide gels. This procedure is known as fluorophore-assisted carbohydrate electrophoresis (FACE) and has been adapted for the detection and quantification of all glycosaminoglycan types...
2018: Methods in Cell Biology
Per Hyltoft Petersen, Flemming Lund, Callum George Fraser, Sverre Sandberg, György Sölétormos
BACKGROUND: Many clinical decisions are based on comparison of patient results with reference intervals. Therefore, estimation of the analytical performance specifications (APS) for the quality that would be required to allow sharing common reference intervals is needed. The International Federation of Clinical Chemistry (IFCC) recommended a minimum of 120 reference individuals to establish reference intervals. This number implies a certain level of quality, which could then be used for defining APS as the maximum combination of analytical bias and imprecision required for sharing common reference intervals, the aim of this investigation...
January 1, 2018: Annals of Clinical Biochemistry
Amine Kassouf, Delphine Jouan-Rimbaud Bouveresse, Douglas N Rutledge
Independent components analysis (ICA) may be considered as one of the most established blind source separation techniques for the treatment of complex data sets in analytical chemistry. Like other similar methods, the determination of the optimal number of latent variables, in this case, independent components (ICs), is a crucial step before any modeling. Therefore, validation methods are required in order to decide about the optimal number of ICs to be used in the computation of the final model. In this paper, three new validation methods are formally presented...
March 1, 2018: Talanta
Stefano Cinti, Luca Fiore, Renato Massoud, Claudio Cortese, Danila Moscone, Giuseppe Palleschi, Fabiana Arduini
The recent goal of sustainability in analytical chemistry has boosted the development of eco-designed analytical tools to deliver fast and cost-effective analysis with low economic and environmental impact. Due to the recent focus in sustainability, we report the use of low-cost filter paper as a sustainable material to print silver electrodes and to load reagents for a reagent-free electrochemical detection of chloride in biological samples, namely serum and sweat. The electrochemical detection of chloride ions was carried out by exploiting the reaction of the analyte (i...
March 1, 2018: Talanta
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