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Analytical chemistry

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https://www.readbyqxmd.com/read/27935275/new-magnetic-graphitized-carbon-black-tio2-composite-for-phosphopeptide-selective-enrichment-in-shotgun-phosphoproteomics
#1
Susy Piovesana, Anna Laura Capriotti, Chiara Cavaliere, Francesca Ferraris, Daniel Iglesias, Silvia Marchesan, Aldo Laganà
Graphitized carbon black (GCB) has been employed for extraction of several classes of analytes, due to the large surface area and the unique chemistry of its surface groups that allows for extracting a wide range of analytes, including polar, acidic compounds. Despite the fact that structurally related materials, such as graphene, found application as hybrid-components in phosphoproteomics, surprisingly, GCB has never been used for the selective enrichment of phosphopeptides. For this purpose, in the present work we used GCB to prepare a magnetic composite with TiO2 (mGCB@TiO2) that was then applied to yeast total extracts...
December 9, 2016: Analytical Chemistry
https://www.readbyqxmd.com/read/27934113/ligating-dopamine-as-signal-trigger-onto-the-substrate-via-metal-catalyst-free-click-chemistry-for-signal-on-photoelectrochemical-sensing-of-ultralow-microrna-levels
#2
Cui Ye, Min Qiang Wang, Zhong Feng Gao, Ying Zhang, Jing Lei Lei, Hong Qun Luo, Nian Bing Li
The efficiency of photon-to-electron conversion is extremely restricted by the electron-hole recombinant. Here, a new photoelectrochemical (PEC) sensing platform has been established based on the signal amplification of click chemistry (CC) via hybridization chain reaction (HCR) for highly sensitive microRNA (miRNA) assay. In this proposal, a preferred electron donor dopamine (DA) was first assembled with designed ligation probe (probe-N3) via amidation reaction to achieve DA-coordinated signal probe (PDA-N3)...
December 6, 2016: Analytical Chemistry
https://www.readbyqxmd.com/read/27917399/retinoids-and-retinal-diseases
#3
Philip D Kiser, Krzysztof Palczewski
Recent progress in molecular understanding of the retinoid cycle in mammalian retina stems from painstaking biochemical reconstitution studies supported by natural or engineered animal models with known genetic lesions and studies of humans with specific genetic blinding diseases. Structural and membrane biology have been used to detect critical retinal enzymes and proteins and their substrates and ligands, placing them in a cellular context. These studies have been supplemented by analytical chemistry methods that have identified small molecules by their spectral characteristics, often in conjunction with the evaluation of models of animal retinal disease...
October 2016: Annual Review of Vision Science
https://www.readbyqxmd.com/read/27916967/steric-and-stereochemical-modulation-in-pyridyl-and-quinolyl-containing-ligands
#4
REVIEW
Zhaohua Dai
Nitrogen-containing pyridine and quinoline are outstanding platforms on which excellent ionophores and sensors for metal ions can be built. Steric and stereochemical effects can be used to modulate the affinity and selectivity of such ligands toward different metal ions on the coordination chemistry front. On the signal transduction front, such effects can also be used to modulate optical responses of these ligands in metal sensing systems. In this review, steric modulation of achiral ligands and stereochemical modulation in chiral ligands, especially ionophores and sensors for zinc, copper, silver, and mercury, are examined using published structural and spectral data...
December 1, 2016: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/27916134/underway-analysis-of-nanomolar-dissolved-reactive-phosphorus-in-oligotrophic-seawater-with-automated-on-line-solid-phase-extraction-and-spectrophotometric-system
#5
Jian Ma, Yuan Yuan, Dongxing Yuan
The automated in-field determination of trace phosphate (and other nutrients) is highly valuable for studying nutrient dynamics and cycling in oligotrophic oceans. Here, we report an automated portable analyzer for week-long underway analysis of nanomolar dissolved reactive phosphorus (DRP) in seawater. The method is based on classic phosphomolybdenum blue (PMB) chemistry combined with on-line solid phase extraction (SPE) and flow analysis. Under optimized conditions, the formed PMB from sample is automatically concentrated on a hydrophilic lipophilic balanced (HLB) copolymer SPE...
January 15, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/27912966/structure-related-related-new-approach-in-the-gc-ms-analysis-of-cathinone-type-synthetic-drugs
#6
Borbála Molnár, Blanka Fodor, Antal Csámpai, Előd Hidvégi, Ibolya Molnár-Perl
A novel, structure-related derivatization principle has been developed in order to quantify cathinone-type synthetic drugs (CTSDs), focusing on the most common pentedrone (PENT), including also 4-fluoromethcathinone (4-FMC), methcathinone (MCTN), 4-methylethcathinone (4-MEC), 3,4-dimethylmethcathinone (3,4-DMMC), and 4-ethylmethcathinone (4-EMC). Firstly, oximated and, secondly, trimethylsilylated CTSD derivatives were characterized by mass fragmentation patterns using GC/MS that led to the development of a harmonized, quantitative, two-steps derivatization methodology...
November 22, 2016: Journal of Chromatography. A
https://www.readbyqxmd.com/read/27907110/electrospray-ionization-efficiency-is-dependent-on-different-molecular-descriptors-with-respect-to-solvent-ph-and-instrumental-configuration
#7
Andreas Kiontke, Ariana Oliveira-Birkmeier, Andreas Opitz, Claudia Birkemeyer
Over the past decades, electrospray ionization for mass spectrometry (ESI-MS) has become one of the most commonly employed techniques in analytical chemistry, mainly due to its broad applicability to polar and semipolar compounds and the superior selectivity which is achieved in combination with high resolution separation techniques. However, responsiveness of an analytical method also determines its suitability for the quantitation of chemical compounds; and in electrospray ionization for mass spectrometry, it can vary significantly among different analytes with identical solution concentrations...
2016: PloS One
https://www.readbyqxmd.com/read/27905935/development-of-a-filter-to-prevent-infections-with-spore-forming-bacteria-in-injecting-drug-users
#8
Nour Alhusein, Jenny Scott, Barbara Kasprzyk-Hordern, Albert Bolhuis
BACKGROUND: In heroin injectors, there have been a number of outbreaks caused by spore-forming bacteria, causing serious infections such as anthrax or botulism. These are, most likely, caused by injecting contaminated heroin, and our aim was to develop a filter that efficiently removes these bacteria and is also likely to be acceptable for use by people who inject drugs (i.e. quick, simple and not spoil the hit). METHODS: A prototype filter was designed and different filter membranes were tested to assess the volume of liquid retained, filtration time and efficiency of the filter at removing bacterial spores...
December 1, 2016: Harm Reduction Journal
https://www.readbyqxmd.com/read/27901132/ligand-density-quantification-on-colloidal-inorganic-nanoparticles
#9
REVIEW
Ashley M Smith, Kathryn A Johnston, Scott E Crawford, Lauren E Marbella, Jill E Millstone
Colloidal inorganic nanoparticles are being used in an increasingly large number of applications ranging from biological imaging to television displays. In all cases, nanoparticle surface chemistry can significantly impact particle physical properties, processing, and performance. The first step in leveraging this tunability is to develop analytical approaches to describe surface chemical features. Some of the most basic descriptors of particle surface chemistry include the quantity, identity, and arrangement of ligands appended to the particle core...
November 30, 2016: Analyst
https://www.readbyqxmd.com/read/27896699/cationized-carbohydrate-gas-phase-fragmentation-chemistry
#10
Benjamin J Bythell, Maha T Abutokaikah, Ashley R Wagoner, Shanshan Guan, Jordan M Rabus
We investigate the fragmentation chemistry of cationized carbohydrates using a combination of tandem mass spectrometry, regioselective labeling, and computational methods. Our model system is D-lactose. Barriers to the fundamental glyosidic bond cleavage reactions, neutral loss pathways, and structurally informative cross-ring cleavages are investigated. The most energetically favorable conformations of cationized D-lactose were found to be similar. In agreement with the literature, larger group I cations result in structures with increased cation coordination number which require greater collision energy to dissociate...
November 28, 2016: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/27894697/an-innovative-ultrasound-assisted-extraction-micro-scale-cell-combined-with-gas-chromatography-mass-spectrometry-in-negative-chemical-ionization-to-determine-persistent-organic-pollutants-in-air-particulate-matter
#11
E Beristain-Montiel, R Villalobos-Pietrini, G E Arias-Loaiza, S L Gómez-Arroyo, O Amador-Muñoz
New clean technologies are needed to determine concentration of organic pollutants without generating more pollution. A method to extract Persistent Organic Pollutants (POPs) from airborne particulate matter was developed using a novel technology recently patented called ultrasound assisted extraction micro-scale cell (UAE-MSC). This technology extracts, filters, collects the sample, and evaporates the solvent, on-line. No sample transfer is needed. The cell minimizes sample manipulation, solvent consumption, waste generation, time, and energy; fulfilling most of the analytical green chemistry protocol...
November 23, 2016: Journal of Chromatography. A
https://www.readbyqxmd.com/read/27874280/a-survey-of-the-mechanisms-of-action-of-anticancer-transition-metal-complexes
#12
Mickaël Marloye, Gilles Berger, Michel Gelbcke, François Dufrasne
Metal complexes have been the subject of numerous investigations in oncology but, despite the plethora of newly synthesized compounds, their precise mechanisms of action remain generally unknown or, for the best, incompletely determined. The continuous development of efficient and sensitive techniques in analytical chemistry and molecular biology gives scientists new tools to gather information on how metal complexes can be effective toward cancer. This review focuses on recent findings about the anticancer mechanism of action of metal complexes and how the ligands can be used to tune their pharmacological and physicochemical properties...
November 22, 2016: Future Medicinal Chemistry
https://www.readbyqxmd.com/read/27872507/calculated-chemistry-parameters-do-they-need-to-be-harmonised
#13
REVIEW
David Hughes, James Cg Doery, Kay Weng Choy, Robert Flatman
In clinical chemistry, harmonisation of the testing process is a global initiative with the purpose of improving patient safety, allowing better integration of research data and enabling the use of national electronic heath records. In Australia, as in other countries, the initial focus has been on the harmonisation of the more commonly measured analytes. There are also a number of calculated parameters, derived from these measured analytes, which could also be considered for harmonisation. Calculated parameters that are reported by laboratories and used for clinical decision-making should undergo the same robust process of harmonisation as is the case for the measured analytes...
August 2016: Clinical Biochemist. Reviews
https://www.readbyqxmd.com/read/27872506/harmonising-adult-reference-intervals-in-australia-and-new-zealand-the-continuing-story
#14
REVIEW
Gus Koerbin, Jillian R Tate
Reference intervals (RIs) are used to help clinicians determine if a patient can be classified as being in a diseased or healthy state and there are often sound scientific and clinical reasons for differences in RIs. One of the current strategic priorities for the Australasian Association of Clinical Biochemists is to encourage and assist laboratories to achieve harmonisation of RIs for common clinical chemistry analytes where sound calibration and traceability are in place. This need is based on good laboratory practice, providing the clinician with results that allow appropriate and reliable clinical interpretation and progression further toward the national e-health framework and a single electronic health record...
August 2016: Clinical Biochemist. Reviews
https://www.readbyqxmd.com/read/27872504/harmonising-reference-intervals-for-three-calculated-parameters-used-in-clinical-chemistry
#15
REVIEW
David Hughes, Gus Koerbin, Julia M Potter, Nicholas Glasgow, Nic West, Walter P Abhayaratna, Juleen Cavanaugh, David Armbruster, Peter E Hickman
For more than a decade there has been a global effort to harmonise all phases of the testing process, with particular emphasis on the most frequently utilised measurands. In addition, it is recognised that calculated parameters derived from these measurands should also be a target for harmonisation. Using data from the Aussie Normals study we report reference intervals for three calculated parameters: serum osmolality, serum anion gap and albumin-adjusted serum calcium. The Aussie Normals study was an a priori study that analysed samples from 1856 healthy volunteers...
August 2016: Clinical Biochemist. Reviews
https://www.readbyqxmd.com/read/27871373/design-and-production-of-antibodies-for-the-detection-of-streptococcus-uberis
#16
K Mihklepp, K Kivirand, M Nikopensius, D Peedel, M Utt, T Rinken
Streptococcus uberis (S. uberis) is an important environmental pathogen causing mastitis in dairy cattle. Mastitis or mammary gland infection is the most common disease in milking cows and cause significant economic burden to farmers due to the reduction of the amount of milk and its quality. The development of rapid analytical methods for the determination of mastitis-causing pathogens in milk is of utmost importance for the early identification of the causes of mastitis and the beginning of timely treatment of cows...
January 2017: Enzyme and Microbial Technology
https://www.readbyqxmd.com/read/27867215/resolving-large-scale-pressures-on-species-and-ecosystems-propensity-modelling-identifies-agricultural-effects-on-streams
#17
Caitlin E Pearson, Steve J Ormerod, William O C Symondson, Ian P Vaughan
Although agriculture is amongst the world's most widespread land uses, studies of its effects on stream ecosystems are often limited in spatial extent. National monitoring data could extend spatial coverage and increase statistical power, but present analytical challenges where covarying environmental variables confound relationships of interest.Propensity modelling is used widely outside ecology to control for confounding variables in observational data. Here, monitoring data from over 3000 English and Welsh river reaches are used to assess the effects of intensive agricultural land cover (arable and pastoral) on stream habitat, water chemistry and invertebrates, using propensity scores to control for potential confounding factors (e...
April 2016: Journal of Applied Ecology
https://www.readbyqxmd.com/read/27861591/rule-mining-for-the-early-prediction-of-chronic-kidney-disease-based-on-metabolomics-and-multi-source-data
#18
Margaux Luck, Gildas Bertho, Mathilde Bateson, Alexandre Karras, Anastasia Yartseva, Eric Thervet, Cecilia Damon, Nicolas Pallet
1H Nuclear Magnetic Resonance (NMR)-based metabolic profiling is very promising for the diagnostic of the stages of chronic kidney disease (CKD). Because of the high dimension of NMR spectra datasets and the complex mixture of metabolites in biological samples, the identification of discriminant biomarkers of a disease is challenging. None of the widely used chemometric methods in NMR metabolomics performs a local exhaustive exploration of the data. We developed a descriptive and easily understandable approach that searches for discriminant local phenomena using an original exhaustive rule-mining algorithm in order to predict two groups of patients: 1) patients having low to mild CKD stages with no renal failure and 2) patients having moderate to established CKD stages with renal failure...
2016: PloS One
https://www.readbyqxmd.com/read/27858797/assessment-of-organic-micropollutants-occurrence-in-treated-wastewater-using-heat-shock-protein-47-stress-responses-in-chinese-hamster-ovary-cells-and-gc-ms-based-non-target-screening
#19
Selma Etteieb, Atsushi Kawachi, Junkyu Han, Foued Elayni, Jamila Tarhouni, Hiroko Isoda
Combining bioassays and analytical chemistry screening is a powerful approach to assess organic micropollutants which are the main contributors to toxic potential in complex mixtures of treated wastewater (TWW). The aim of this study was to perform a comprehensive toxicity assessment of treated effluents using stress response bioassays and then to assess the occurrence of the organic micropollutants which were responsible for this biological response using gas chromatography coupled with a mass spectrometry detector (GC/MS)...
November 2016: Water Science and Technology: a Journal of the International Association on Water Pollution Research
https://www.readbyqxmd.com/read/27858150/coffee-and-oxidative-stress-a-human-intervention-study
#20
Sergey Shaposhnikov, Thomas Hatzold, Naouale El Yamani, Philip Mark Stavro, Yolanda Lorenzo, Maria Dusinska, Astrid Reus, Wilrike Pasman, Andrew Collins
PURPOSE: Coffee is known to contain phytochemicals with antioxidant potential. The aim of this study was to investigate possible antioxidant effects of coffee in healthy human volunteers. METHODS: A placebo-controlled intervention trial was carried out on 160 healthy human subjects, randomised into three groups, receiving 3 or 5 cups of study coffee or water per day, for 8 weeks. Blood samples were taken before, during, and after the intervention. Serum was used for analysis of blood lipids and standard clinical chemistry analytes...
November 17, 2016: European Journal of Nutrition
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