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Analytical Techniques

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https://www.readbyqxmd.com/read/29346326/lipid-membrane-nanosensors-for-environmental-monitoring-the-art-the-opportunities-and-the-challenges
#1
REVIEW
Georgia-Paraskevi Nikoleli, Dimitrios Nikolelis, Christina G Siontorou, Stephanos Karapetis
The advent of nanotechnology has brought along new materials, techniques, and concepts, readily adaptable to lipid membrane-based biosensing. The transition from micro-sensors to nano-sensors is neither straightforward nor effortless, yet it leads to devices with superior analytical characteristics: ultra-low detectability, small sample volumes, better capabilities for integration, and more available bioelements and processes. Environmental monitoring remains a complicated field dealing with a large variety of pollutants, several decomposition products, or secondary chemicals produced ad hoc in the short- or medium term, many sub-systems affected variously, and many processes largely unknown...
January 18, 2018: Sensors
https://www.readbyqxmd.com/read/29345258/combination-of-a-graphene-sers-substrate-and-magnetic-solid-phase-micro-extraction-used-for-the-rapid-detection-of-trace-illegal-additives
#2
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
https://www.readbyqxmd.com/read/29344964/recent-advances-and-opportunities-in-proteomic-analyses-of-tumor-heterogeneity
#3
REVIEW
Nicholas W Bateman, Thomas P Conrads
Solid tumor malignancies comprise a highly variable admixture of tumor and non-tumor cellular populations, forming a complex cellular ecosystem and tumor microenvironment. This tumor heterogeneity is not incidental and is known to correlate with poor patient prognosis for many cancer types. Indeed, non-malignant cell populations, such as vascular endothelial and immune cells, are known to play key roles supporting and, in some cases, driving aggressive tumor biology and represent targets of emerging therapeutics, such as anti-angiogenesis and immune checkpoint inhibitors...
January 17, 2018: Journal of Pathology
https://www.readbyqxmd.com/read/29344754/green-and-sustainable-separation-of-natural-products-from-agro-industrial-waste-challenges-potentialities-and-perspectives-on-emerging-approaches
#4
REVIEW
Vânia G Zuin, Luize Z Ramin
New generations of biorefinery combine innovative biomass waste resources from different origins, chemical extraction and/or synthesis of biomaterials, biofuels, and bioenergy via green and sustainable processes. From the very beginning, identifying and evaluating all potentially high value-added chemicals that could be removed from available renewable feedstocks requires robust, efficient, selective, reproducible, and benign analytical approaches. With this in mind, green and sustainable separation of natural products from agro-industrial waste is clearly attractive considering both socio-environmental and economic aspects...
January 17, 2018: Topics in Current Chemistry (Journal)
https://www.readbyqxmd.com/read/29343620/comparative-extractables-study-of-autoclavable-polyethersulfone-filter-cartridges-for-sterile-filtration
#5
Roberto Menzel, Ina Pahl, Thomas Loewe, Armin Hauk
Sterile filters are ubiquitous in biopharmaceutical manufacturing processes. Since such filters are in direct contact with the process fluid, profiling of the extractables is of utmost importance. The work presented here reveals the extractables profile from filter cartridges for sterilizing grade filtration, which were obtained from six different vendors. All filters contain a 0.2 μm polyethersulfone (PES) membrane for sterile filtration combined with a PES pre-filter with retention rates spanning from 0...
January 17, 2018: PDA Journal of Pharmaceutical Science and Technology
https://www.readbyqxmd.com/read/29341918/asymmetric-flow-field-flow-fractionation-for-the-characterization-of-globule-size-distribution-in-complex-formulations-a-cyclosporine-ophthalmic-emulsion-case
#6
Haiou Qu, Jiang Wang, Yong Wu, Jiwen Zheng, Yellela S R Krishnaiah, Mohammad Absar, Stephanie Choi, Muhammad Ashraf, Celia N Cruz, Xiaoming Xu
Commonly used characterization techniques such as cryogenic-transmission electron microscopy (cryo-TEM) and batch-mode dynamic light scattering (DLS) are either time consuming or unable to offer high resolution to discern the poly-dispersity of complex drug products like cyclosporine ophthalmic emulsions. Here, a size-based separation and characterization method for globule size distribution using an asymmetric flow field flow fractionation (AF4) is reported for comparative assessment of cyclosporine ophthalmic emulsion drug products (model formulation) with a wide size span and poly-dispersity...
January 13, 2018: International Journal of Pharmaceutics
https://www.readbyqxmd.com/read/29341772/determinant-diagrammatic-monte%C3%A2-carlo-algorithm-in-the-thermodynamic-limit
#7
Riccardo Rossi
We present a simple trick that allows us to consider the sum of all connected Feynman diagrams at fixed position of interaction vertices for general fermionic models, such that the thermodynamic limit can be taken analytically. With our approach one can achieve superior performance compared to conventional diagrammatic Monte Carlo algorithm, while rendering the algorithmic part dramatically simpler. By considering the sum of all connected diagrams at once, we allow for massive cancellations between different diagrams, greatly reducing the sign problem...
July 28, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/29341609/probing-and-quantifying-the-food-borne-pathogens-and-toxins-from-in-vitro-to-in-vivo
#8
Jing-Min Liu, Zhi-Hao Wang, Hui Ma, Shuo Wang
Development of real-time and in situ analytical methods for determination of food-borne pathogens and toxins ingested into human body would be a promising research direction in the food safety area. The present review starts with summarization of the up-to-date progress of the nanomaterial-assisted in vitro detection methods for pathogens and toxins, and finally focused on application of animal bioimaging to in vivo study, including prospective strategies for in vivo quantification of target pathogens or toxins and in vivo investigation of their behaviors inside the living body, with the assistance of real-time and non-invasive optical bioimaging...
January 17, 2018: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/29341601/determining-double-bond-position-in-lipids-using-online-ozonolysis-coupled-to-liquid-chromatography-and-ion-mobility-mass-spectrometry
#9
Rachel A Harris, Jody C May, Craig A Stinson, Yu Xia, John A McLean
The increasing focus on lipid metabolism has revealed a need for analytical techniques capable of structurally characterizing lipids with a high degree of specificity. Lipids can exist as any one of a large number of double bond positional isomers, which are indistinguishable by single-stage mass spectrometry alone. Ozonolysis reactions coupled to mass spectrometry have previously been demonstrated as a means for localizing double bonds in unsaturated lipids. Here we describe an online, solution-phase reactor using ozone produced via a low-pressure mercury lamp, which generates aldehyde products diagnostic of cleavage at a particular double bond position...
January 17, 2018: Analytical Chemistry
https://www.readbyqxmd.com/read/29340755/multiple-invasion-speeds-in-a-two-species-integro-difference-competition-model
#10
Bingtuan Li
We study an integro-difference competition model for the case that two species consecutively invade a habitat. We show that if a species spreads into a traveling wave of its rival, or if two species expand their spatial ranges in both directions, in a direction where open space is available, the species with larger invasion speed can always establish a wave moving into open space with its own speed. We demonstrate that when one species is stronger in competition, under appropriate conditions, the speeds at which the boundaries between two species move can be analytically determined...
January 16, 2018: Journal of Mathematical Biology
https://www.readbyqxmd.com/read/29339510/artificial-intelligence-exploration-of-unstable-protocells-leads-to-predictable-properties-and-discovery-of-collective-behavior
#11
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
https://www.readbyqxmd.com/read/29339233/ftir-as-an-easy-and-fast-analytical-approach-to-follow-up-microbial-growth-during-fungal-pretreatment-of-poplar-wood-with-phanerochaete-chrysosporium
#12
I Cornet, N Wittner, G Tofani, S Tavernier
Since the determination of the fermentation kinetics is one of the main challenges in solid state fermentation, the quantitative measurement of biomass growth during microbial pretreatment by FTIR spectroscopy in Attenuated Total Reflectance mode was evaluated. Peaks at wave numbers of 1651 cm-1 and 1593 cm-1 showed to be affected during pretreatment of poplar wood particles by Phanerochaete chrysosporium MUCL 19343. Samples with different microbial biomass fractions were obtained from two different experiments, i...
January 12, 2018: Journal of Microbiological Methods
https://www.readbyqxmd.com/read/29339058/carboxylic-group-riched-graphene-oxide-based-disposable-electrochemical-immunosensor-for-cancer-biomarker-detection
#13
Sajid Rauf, Geetesh K Mishra, Jahanzaib Azhar, Rupesh K Mishra, K Yugender Goud, Muhammad Azhar Hayat Nawaz, Jean Louis Marty, Akhtar Hayat
In this work, we have developed for the first time a carboxylic group riched graphene oxide based disposable electrochemical immunosensor for cancer biomarker detection using methylene blue (MB). The developed immunosensor is highly sensitive for detection of biomarker Mucin1 (MUC1) in human serum samples. Development of this disposable electrochemical immunosensor was premeditated by applying specific monoclonal antibodies against MUC1. In this method, we explored highly conductive surface of carboxylic group (-COOH-) rich graphene oxide (GO) on screen-printed carbon electrodes (SPCE)...
January 12, 2018: Analytical Biochemistry
https://www.readbyqxmd.com/read/29338547/neuroimaging-meta-analysis-of-cannabis-use-studies-reveals-convergent-functional-alterations-in-brain-regions-supporting-cognitive-control-and-reward-processing
#14
Julio A Yanes, Michael C Riedel, Kimberly L Ray, Anna E Kirkland, Ryan T Bird, Emily R Boeving, Meredith A Reid, Raul Gonzalez, Jennifer L Robinson, Angela R Laird, Matthew T Sutherland
Lagging behind rapid changes to state laws, societal views, and medical practice is the scientific investigation of cannabis's impact on the human brain. While several brain imaging studies have contributed important insight into neurobiological alterations linked with cannabis use, our understanding remains limited. Here, we sought to delineate those brain regions that consistently demonstrate functional alterations among cannabis users versus non-users across neuroimaging studies using the activation likelihood estimation meta-analysis framework...
January 1, 2018: Journal of Psychopharmacology
https://www.readbyqxmd.com/read/29338194/sequential-and-selective-detection-of-two-molecules-with-a-single-solid-contact-chronopotentiometric-ion-selective-electrode
#15
Jiawang Ding, Nana Yu, Xuedong Wang, Wei Qin
A polymeric membrane ion-selective electrode (ISE) is typically designed for determination of one specific ion using conventional method. In this work, we demonstrate a simple, versatile and sensitive platform for simultaneous detection of two molecules with a single ISE. Under a series of periodic galvanostatic polarization, a solid-contact ISE without ion exchanger properties under zero-current conditions has been successfully used for simultaneous detection of two opposite charged ions with high sensitivity, good selectivity and fast reversibility...
January 17, 2018: Analytical Chemistry
https://www.readbyqxmd.com/read/29337915/comparing-classic-and-interval-analytical-hierarchy-process-methodologies-for-measuring-area-level-deprivation-to-analyze-health-inequalities
#16
Pablo Cabrera-Barona, Omid Ghorbanzadeh
Deprivation indices are useful measures to study health inequalities. Different techniques are commonly applied to construct deprivation indices, including multi-criteria decision methods such as the analytical hierarchy process (AHP). The multi-criteria deprivation index for the city of Quito is an index in which indicators are weighted by applying the AHP. In this research, a variation of this index is introduced that is calculated using interval AHP methodology. Both indices are compared by applying logistic generalized linear models and multilevel models, considering self-reported health as the dependent variable and deprivation and self-reported quality of life as the independent variables...
January 16, 2018: International Journal of Environmental Research and Public Health
https://www.readbyqxmd.com/read/29337594/solid-phase-microextraction-techniques-in-determination-of-biomarkers
#17
Samin Hamidi, Nastaran Alipour-Ghorbani, Aliasghar Hamidi
The detection and quantification of biomarkers is gaining attention in medical research and diagnostics communities. Biomarkers cover a range from gases to biological macromolecules. Because of the nanomolar range levels of typical biomarkers in plasma, blood, urine, exhalation samples, and other biological fluids as well as complex matrix of biological media, adequate sample preparation methods should be used for quantification of biomarkers. The performance of an analytical method for biomarkers should support reproducible and accurate data...
January 16, 2018: Critical Reviews in Analytical Chemistry
https://www.readbyqxmd.com/read/29337180/impact-of-an-acute-surgical-unit-in-appendicectomy-outcomes-a-systematic-review-and-meta-analysis
#18
REVIEW
Ishwarya Balasubramanian, Ben Creavin, Des Winter
BACKGROUND: The provision of emergency general surgical services is undergoing a paradigm shift towards a consultant led, patient centered model in order to improve patient outcomes. The aim of this current study is to use meta-analytical techniques to assess the efficacy of acute surgical unit (ASU) in appendectomy. METHODS: A meta-analysis was conducted according to the PRISMA guidelines. A comprehensive literature search of PubMed, Embase and Scopus for published studies comparing ASU and traditional (TRAD) model on appendectomy outcomes was performed...
January 11, 2018: International Journal of Surgery
https://www.readbyqxmd.com/read/29336854/morphologically-directed-raman-spectroscopy-for-forensic-soil-analysis
#19
Brooke W Kammrath, Andrew Koutrakos, Josemar Castillo, Cathryn Langley, Deborah Huck-Jones
Morphologically-directed Raman spectroscopy (MDRS) is a novel yet reliable analytical technique that can be used for a variety of forensic applications, enabling scientists to gain more information from samples than they obtain using more traditional methods. In soil forensics, MDRS delivers particle size distribution and microscopic morphological characteristics for the particles present, and at the same time allows secure mineral identification. In this article, we explore the benefits of utilizing soil in forensic investigations, and demonstrate the value of applying MDRS...
December 28, 2017: Forensic Science International
https://www.readbyqxmd.com/read/29336485/a-multimodal-microcharacterisation-of-trace-element-zonation-and-crystallographic-orientation-in-natural-cassiterite-by-combining-cathodoluminescence-ebsd-epma-and-contribution-of-confocal-raman-in-sem-imaging
#20
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
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