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Analytical Techniques

Ireneusz Sowa, Magdalena Wójciak-Kosior, Maciej Strzemski, Jan Sawicki, Michał Staniak, Sławomir Dresler, Wojciech Szwerc, Jarosław Mołdoch, Michał Latalski
Polyaniline (PANI) is one of the best known conductive polymers with multiple applications. Recently, it was also used in separation techniques, mostly as a component of composites for solid-phase microextraction (SPME). In the present paper, sorbent obtained by in situ polymerization of aniline directly on silica gel particles (Si-PANI) was used for dispersive solid phase extraction (d-SPE) and matrix solid-phase extraction (MSPD). The efficiency of both techniques was evaluated with the use of high performance liquid chromatography with diode array detection (HPLC-DAD) quantitative analysis...
March 22, 2018: Materials
Cristina Teixidó, Ana Giménez-Capitán, Miguel Ángel Molina-Vila, Vicente Peg, Niki Karachaliou, Alejandra Rodríguez-Capote, Josep Castellví, Rafael Rosell
CONTEXT: - Technologic advances have contributed to the increasing relevance of RNA analysis in clinical oncology practice. The different genetic aberrations that can be screened with RNA include gene fusions and splice variants. Validated methods of identifying these alterations include fluorescence in situ hybridization, immunohistochemistry, reverse transcription-polymerase chain reaction, and next-generation sequencing, which can provide physicians valuable information on disease and treatment of cancer patients...
April 2018: Archives of Pathology & Laboratory Medicine
Mayura Kale, Gajanan Sonwane, Rajesh Nawale, Vishnukant Mourya
There has been a rapid surge in the research and exchange of ideas in various areas of chemistry such as organic, pharmaceutical, analytical, and medicinal chemistry. It is well recognized that heterocycles are vital components of many biochemical processes. Pharma industry comprises of more than 75% of top selling drugs that are of heterocyclic origin. Among many diseases, cancer can be considered to be a dreaded disease that has overtaken the masses across the globe. Hence, there has been a need to develop drugs that are less toxic and do not provide resistance in the long run...
March 20, 2018: Current Computer-aided Drug Design
Tom Dyer, Ngamta Thamwattana, Barry Cox
The low bending rigidity of graphene facilitates the formation of folds into the structure. This curvature change affects the reactivity and electron transport of the sheet. One novel extension of this is the intercalation of small molecules into these folds. We construct a model incorporating a single-walled carbon nanotube into a sheet of folded graphene. Variational calculus techniques are employed to determine the minimum energy structure and the resulting curves are shown to agree well with molecular dynamics study...
March 22, 2018: Journal of Molecular Modeling
Andrew Todd Ham
A thorough understanding of the governing concepts of polarity behavior within electroencephalograph (EEG) promotes analytical and thus technical proficiency of the technologist by providing a skill set to logically resolve the myriad of waveform presentations that are expected across all montage derivations. In addition to avoiding a reliance on cursory conceptualization techniques, a solid grasp of the underlying theory of EEG polarity permits a fundamental realization of the cause-effect relationships between the various directions of eye movement and the resulting multitude of wave deflection presentations observed across all montages...
2018: Neurodiagnostic Journal
Xuelin Cui, Lamine Mili, Ge Wang, Hengyong Yu
Since their inceptions, the multimodal imaging techniques have received a great deal of attention for achieving enhanced imaging performance. In this work, a novel joint reconstruction framework using sparse computed tomography (CT) and magnetic resonance imaging (MRI) data is developed and evaluated. CT and MRI images are synchronously acquired and registered from a hybrid CT-MRI platform. Because image data are highly undersampled, analytic methods are unable to generate decent image quality. To overcome this drawback, we resort to the compressed sensing (CS) techniques, which employ sparse priors that result from an application of a wavelet transform...
March 15, 2018: Journal of X-ray Science and Technology
Martin Köhler, Christoph Neff, Camilo Perez, Cyrill Brunner, Els Pardon, Jan Steyaert, Gisbert Schneider, Kaspar P Locher, Renato Zenobi
The application of nanobodies as binding partners for structure stabilization in protein x-ray crystallography is taking an increasingly important role in structural biology. However, the addition of nanobodies to the crystallization matrices might complicate the optimization of the crystallization process, which is why analytical techniques to screen and characterize suitable nanobodies are useful. Here, we show how chemical cross-linking combined with high-mass matrix-assisted laser/desorption ionization mass spectrometry can be employed as a fast screening technique to determine binding specificities of intact nanobody•membrane protein complexes...
March 21, 2018: Analytical Chemistry
Subhasis Das, Manideepa Sengupta, Arijit Bag, Mumtaj Shah, Ankur Bordoloi
A synergistic approach was made to develop a highly stable and carbon resistant catalyst system based on cobalt and nickel supported over modified mesoporous silica for the dry reforming of methane (DRM). Modified mesoporous silica is prepared by a hydrothermal method, and the total Co & Ni composition is taken at around 5% by using the deposition-precipitation technique. CO2 reforming with methane was performed at 400-800 °C under atmospheric pressure as well as at a pressure of 1 MPa, keeping the CH4/CO2 ratio equal to unity...
March 21, 2018: Nanoscale
Daniele Giuffrida, Mariosimone Zoccali, Adriana Arigò, Francesco Cacciola, Coralia Osorio Roa, Paola Dugo, Luigi Mondello
An on-line method based on the coupling of supercritical fluid extraction and supercritical fluid chromatography with triple quadrupole mass spectrometry detection (SFESFCQqQ/MS) for the native carotenoids characterization and apocarotenoids detection in yellow tamarillo was developed for the first time; this is the first work reporting the application of this methodology for the apocarotenoids analysis in any matrix. An off-line liquid extraction (LE) and analysis by LC-PDA-MS, using both a conventional C30 (3 μm I...
March 17, 2018: Archives of Biochemistry and Biophysics
Jiuyan Chen, Shurui Cao, Ming Zhu, Cunxian Xi, Lei Zhang, Xianliang Li, Guomin Wang, Yuantao Zhou, Zhiqiong Chen
An adsorbent, consisting of silica-coated Fe3 O4 grafted graphene oxide and β-cyclodextrin (Fe3 O4 @SiO2 /GO/β-CD), which possessed the merits of antioxidation, superparamagnetism, high surface area, high supramolecular recognition and environment friendly, was successfully fabricated. Considering the synergy between β-CD and graphene oxide in adsorption mechanism, the synthesized adsorbent could grasp compounds especially with aromatic structures through π-π interaction, hydrophobic interaction and host-guest inclusion complex forming...
March 4, 2018: Journal of Chromatography. A
Erin J Sanchez, Lee F Gabler, Ann B Good, James R Funk, Jeff R Crandall, Matthew B Panzer
BACKGROUND: Head kinematics generated by laboratory reconstructions of professional football helmet impacts have been applied to computational models to study the biomechanics of concussion. Since the original publication of this data, techniques for evaluating accelerometer consistency and error correction have been developed. This study applies these techniques to the original reconstruction data and reanalyzes the results given the current state of concussion biomechanics. METHODS: Consistency checks were applied to the sensor data collected in the head of each test dummy...
March 14, 2018: Clinical Biomechanics
Tongbai Xu, Dongsheng Li, Yuan He, Fuliang Zhang, Man Qiao, Yanhua Chen
BACKGROUND: The anti-cancer role of metformin has been reported in many different kinds of solid tumors, but how it affects non-small cell lung cancer (NSCLC) is currently elusive. The aim of this study was to investigate the influence of metformin treatment on diabetic NSCLC. METHODS: Two hundred fifty-five patients of diabetic NSCLC receiving therapy in our hospital from 2014 to 2016 were enrolled in our study. The information on clinical diagnosis, pathology, and prognosis as well as the influence of metformin in diabetic NSCLC were collected and assessed...
March 20, 2018: World Journal of Surgical Oncology
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
Eric Seiti Yamanaka, Luis A Tortajada-Genaro, Nuria Pastor, Ángel Maquieira
The genotyping of a single-nucleotide polymorphism (SNP) is addressed through methods based on loop-mediated isothermal amplification (LAMP) combined with user-friendly optical read-outs to cover the current demand for point-of-care DNA biomarker detection. The modification of primer design and reaction composition improved the assay selectivity yielding allele-specific results and reducing false-positive frequency. Furthermore, the reduced cost, ease of use and effectiveness of colorimetric detection (solution and hybridisation chip formats) were availed for the image capture by a smartphone, reching high sensitivity...
March 8, 2018: Biosensors & Bioelectronics
Münteha Nur Sonuç Karaboğa, Mustafa Kemal Sezgintürk
This paper illustrates a new and sensitive electrochemical immunosensor for the analysis of C-reactive protein. Indium Tin Oxide (ITO) disposable sheets were modified by using 3-cyanopropyltrimethoxysilane (CPTMS) self-assembled monolayers (SAMs) for the first time for immobilizing the anti-CRP antibody via covalent interactions without the need for any cross-linking agent. Cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS), as well as square wave voltammetry (SWV) methods were applied to characterize immobilization steps of anti-CRP and to determine the CRP concentration...
March 12, 2018: Journal of Pharmaceutical and Biomedical Analysis
Żaneta Bargańska, Dimitra Lambropoulou, Jacek Namieśnik
Bumblebees play an important role in the pollination process of many crops and flowers. Therefore, taking action to protect and assess the impact of pesticides on these insects is fully justified. Pesticides may cause mortality and also sub-lethal effects that are not always directly visible. Bumblebees, like honeybees, can be used as indicators for environmental monitoring contamination. Two approaches are mainly used for the determination of pesticide residues in pollinating insects: a toxicological test (to know effects) and multi-stage analytical methodologies (to know exposure)...
March 20, 2018: Critical Reviews in Analytical Chemistry
Verónica Giubergia, María J Ramirez Farías, Verónica Pérez, Adriana González, Nancy Crespi, Nora Fridman, Claudio Castaños
INTRODUCTION: Severe asthma accounts for 5-7% of all asthma cases. The World Health Organization proposed a follow-up protocol to classify cases into severe, treatment-resistant asthma (STRA) or severe, difficult-to-control asthma (SDCA). OBJECTIVE: To analyze the clinical, functional, and therapeutic characteristics of patients with STRA or SDCA. METHODS: Cross-sectional, observational, and analytical study to assess the diagnosis, the extent of control (clinical and functional), comorbidities, treatment adherence, inhalation technique, and environmental factors in patients with severe asthma...
April 1, 2018: Archivos Argentinos de Pediatría
Mohammad Yazdi, Orhan Korhan, Sahand Daneshvar
This study aimed at establishing fault tree analysis (FTA) using expert opinion to compute the probability of an event. Thus, in order to find the probability of the top event (TE), all probabilities of the basic events (BEs) should be available when FTA is drawn for an event. In this case, employing expert judgment can be used as an alternative to failure data in an awkward situation. The fuzzy analytical hierarchy process (FAHP) as a standard technique is used to give a specific weight to each expert, and fuzzy set theory is engaged for aggregating expert opinion...
March 20, 2018: International Journal of Occupational Safety and Ergonomics: JOSE
Fatemeh Mahmoodani, Conrad O Perera, Grant Abernethy, Bruno Fedrizzi, David Greenwood, Hong Chen
In a successful fortification program, the stability of micronutrients added to the food is one of the most important factors. The added vitamin D3 is known to sometimes decline during storage of fortified milks, and oxidation through fatty acid lipoxidation could be suspected as the likely cause. Identification of vitamin D3 oxidation products (VDOPs) in natural foods is a challenge due to the low amount of their contents and their possible transformation to other compounds during analysis. The main objective of this study was to find a method to extract VDOPs in simulated whole milk powder and to identify these products using LTQ-ion trap, Q-Exactive Orbitrap and triple quadrupole mass spectrometry...
March 19, 2018: Journal of the American Society for Mass Spectrometry
J K Dubey, S K Patyal, Ajay Sharma
In the present day scenario of increasing awareness and concern about the pesticides, it is very important to ensure the quality of data being generated in pesticide residue analysis. To impart confidence in the products, terms like quality assurance and quality control are used as an integral part of quality management. In order to ensure better quality of results in pesticide residue analysis, validation of analytical methods to be used is extremely important. Keeping in view the importance of validation of method, the validation of QuEChERS (quick, easy, cheap, effective, rugged, and safe) a multiresidue method for extraction of 13 organochlorines and seven synthetic pyrethroids in fruits and vegetables followed by GC ECD for quantification was done so as to use this method for analysis of samples received in the laboratory...
March 19, 2018: Environmental Monitoring and Assessment
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