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https://www.readbyqxmd.com/read/28806859/analysis-of-low-molecular-weight-compounds-using-maldi-and-ldi-tof-ms-direct-detection-of-active-pharmaceutical-ingredients-in-different-formulations
#1
João L Bronzel, Cintia D F Milagre, Humberto M S Milagre
Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry (MALDI-MS) is a high throughput, easy to use analytical technique. The simple sample preparation of this technique and its tolerance to the presence of contaminants are among its advantages. In contrast, depending on the matrix used, MALDI can ionize and generates ions in the low m/z range that complicate the interpretation of the spectra of low molecular weight compounds. To address this issue, one can envisage the use of tunable ionic matrices that can reduce the low m/z interferents...
August 14, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28806700/a-large-raman-scattering-cross-section-molecular-embedded-sers-aptasensor-for-ultrasensitive-aflatoxin-b1-detection-using-cs-fe3o4-for-signal-enrichment
#2
Quansheng Chen, Mingxiu Yang, Xiaojing Yang, Huanhuan Li, Zhiming Guo, M H Rahma
With growing concern on oil safety problems, developing a simple and sensitive method to detect Aflatoxin B1 (AFB1), a common mycotoxin in peanut oil, is very necessary. In this study, Surface-enhanced Raman Scattering (SERS) aptasensor was developed for ultrasensitive AFB1 detection using the amino-terminal AFB1 aptamer (NH2-DNA1); and thiol-terminal AFB1 complementary aptamer (SH-DNA2) conjugated magnetic-beads (CS-Fe3O4) as enrichment nanoprobe and AuNR@DNTB@Ag nanorods (ADANRs) as reporter nanoprobe respectively...
August 10, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28806393/craf-gene-fusions-in-pediatric-low-grade-gliomas-define-a-distinct-drug-response-based-on-dimerization-profiles
#3
P Jain, T M Fierst, H J Han, T E Smith, A Vakil, P J Storm, A C Resnick, A J Waanders
Pediatric low-grade gliomas (PLGGs) are commonly associated with BRAF gene fusions that aberrantly activate the mitogen-activated protein kinase (MAPK) signaling pathway. This has led to PLGG clinical trials utilizing RAF- and MAPK pathway-targeted therapeutics. Whole-genome profiling of PLGGs has also identified rare gene fusions involving another RAF isoform, CRAF/RAF1, in PLGGs and cancers occuring in adults. Whereas BRAF fusions primarily dysregulate MAPK signaling, the CRAF fusions QKI-RAF1 and SRGAP3-RAF1 aberrantly activate both the MAPK and phosphoinositide-3 kinase/mammalian target of rapamycin (PI3K/mTOR) signaling pathways...
August 14, 2017: Oncogene
https://www.readbyqxmd.com/read/28806198/pre-treatment-integrase-strand-transfer-inhibitor-resistance-in-north-carolina-from-2010-2016
#4
Timothy W Menza, Rachael Billock, Erika Samoff, Joseph J Eron, Ann M Dennis
OBJECTIVE: We sought to define the prevalence of pre-treatment INSTI resistance and assess the transmission networks of those with pre-treatment INSTI resistance. DESIGN: A retrospective cohort study of HIV-positive patients with genotypic resistance testing sent to a single referral laboratory in North Carolina between 2010 and 2016. METHODS: We linked genotype and public health data for in-care HIV-positive individuals to determine the prevalence of INSTI resistance among treatment-naïve (defined as those with a first genotype ≤3 months after diagnosis) and treatment-experienced (defined as those with a first genotype >3 months after diagnosis) patients...
August 12, 2017: AIDS
https://www.readbyqxmd.com/read/28805866/low-spin-m-ii-l-2-and-m-iii-l-2-m-fe-and-co-complexes-of-tridentate-azo-containing-pyridine-pyrazine-amide-ligands-structures-properties-and-redox-potential-correlations
#5
Arunava Sengupta, Amit Rajput, Suman K Barman, Rabindranath Mukherjee
Using deprotonated forms of tridentate azo-containing pyridine-2-/pyrazine-2-carboxamide 2-[N-(2-phenylazo)carbamoyl]-pyridine/pyrazine, seven bis-ligand complexes of Fe(II)/Co(II) and Fe(III)/Co(III) have been synthesized. Molecular structures of six of them reveal that these six-coordinate complexes utilize all available donor sites of the ligands and assume M(II/III)N2(pyridine/pyrazine)N'2(amide)N''2(azo) coordination. Complexes of Fe(II) and Co(III) are diamagnetic and those of Fe(III) and Co(II) are paramagnetic (S = 1/2; room-temperature magnetic data and EPR spectra)...
August 14, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28805861/site-dependent-effects-of-methylation-on-the-electronic-spectra-of-jet-cooled-methylated-xanthine-compounds
#6
Doory Kim, Key Young Yang, Hyung Min Kim, Tae-Rae Kim, Nam Joon Kim, Seokmin Shin, Seong Keun Kim
We obtained the electronic spectra of various methylated xanthine compounds including caffeine in a supersonic jet by resonant two-photon ionization spectroscopy. The methyl group in the tested methylated xanthine compounds has a distinct, site-dependent effect on the electronic spectrum. Methylation at the N3 position causes a significant red shift of the ππ* state, whereas methylation at the N1 position has only minimal effects on the electronic spectrum. The notably broad spectra of theobromine and caffeine result from methyl substitution at the N7 position, which causes a large displacement between the potential energy surfaces of the S0 and S1 states, and a strong vibronic coupling...
August 14, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28805852/the-effect-of-sub-zero-temperature-on-the-formation-and-composition-of-secondary-organic-aerosol-from-ozonolysis-of-alpha-pinene
#7
K Kristensen, L N Jensen, M Glasius, M Bilde
This study presents a newly constructed temperature controlled cold-room smog chamber at Aarhus University, Denmark. The chamber is herein utilized to study the effect of sub-zero temperature on the formation and chemical composition of secondary organic aerosol (SOA) from ozone initiated oxidation of α-pinene. The chemical composition of α-pinene SOA formed from dark ozonolysis of α-pinene at 293 K and 258 K was investigated using High-Resolution Time-of-Flight Aerosol Mass Spectrometry (HR-ToF-AMS) and Ultra-High Performance Liquid Chromatography/Electrospray Ionization Quadrupole Time-of-Flight Mass Spectrometry (UHPLC/ESI-qToF-MS)...
August 14, 2017: Environmental Science. Processes & Impacts
https://www.readbyqxmd.com/read/28805849/topology-of-polymer-chains-under-nanoscale-confinement
#8
Vahid Satarifard, Maziar Heidari, Samaneh Mashaghi, Sander J Tans, Mohammad Reza Ejtehadi, Alireza Mashaghi
Spatial confinement limits the conformational space accessible to biomolecules but the implications for bimolecular topology are not yet known. Folded linear biopolymers can be seen as molecular circuits formed by intramolecular contacts. The pairwise arrangement of intra-chain contacts can be categorized as parallel, series or cross, and has been identified as a topological property. Using molecular dynamics simulations, we determine the contact order distributions and topological circuits of short semi-flexible linear and ring polymer chains with a persistence length of lp under a spherical confinement of radius Rc...
August 14, 2017: Nanoscale
https://www.readbyqxmd.com/read/28805835/a-comparison-study-on-polysaccharides-extracted-from-laminaria-japonica-using-different-methods-structural-characterization-and-bile-acid-binding-capacity
#9
Jie Gao, Lianzhu Lin, Baoguo Sun, Mouming Zhao
In this study, the structural characterization and bile acid-binding capacity of Laminaria japonica polysaccharides (LP), obtained by seven different extraction methods, were investigated. The results indicated that extraction methods exhibited significant effects on extraction yield, molecular weight, monosaccharide composition and the content of neutral sugar, fucose, uronic acid and sulfate of LP. AFM analysis indicated that LP extracted by different methods exhibited certain different, flexible and worm-like chains with many branches...
August 14, 2017: Food & Function
https://www.readbyqxmd.com/read/28805825/the-processing-and-heterostructuring-of-silk-with%C3%A2-light
#10
Mehra S Sidhu, Bhupesh Kumar, Kamal P Singh
Spider silk is a tough, elastic and lightweight biomaterial, although there is a lack of tools available for non-invasive processing of silk structures. Here we show that nonlinear multiphoton interactions of silk with few-cycle femtosecond pulses allow the processing and heterostructuring of the material in ambient air. Two qualitatively different responses, bulging by multiphoton absorption and plasma-assisted ablation, are observed for low- and high-peak intensities, respectively. Plasma ablation allows us to make localized nanocuts, microrods, nanotips and periodic patterns with minimal damage while preserving molecular structure...
August 14, 2017: Nature Materials
https://www.readbyqxmd.com/read/28805699/predicting-and-interpreting-the-structure-of-type-iv-pilus-of-electricigens-by-molecular-dynamics-simulations
#11
Chuanjun Shu, Ke Xiao, Changchang Cao, Dewu Ding, Xiao Sun
Nanowires that transfer electrons to extracellular acceptors are important in organic matter degradation and nutrient cycling in the environment. Geobacter pili of the group of Type IV pilus are regarded as nanowire-like biological structures. However, determination of the structure of pili remains challenging due to the insolubility of monomers, presence of surface appendages, heterogeneity of the assembly, and low-resolution of electron microscopy techniques. Our previous study provided a method to predict structures for Type IV pili...
August 12, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28805698/artemisia-iwayomogi-extract-attenuates-high-fat-diet-induced-hypertriglyceridemia-in-mice-potential-involvement-of-the-adiponectin-ampk-pathway-and-very-low-density-lipoprotein-assembly-in-the-liver
#12
Jinhui Lee, Vikram P Narayan, Eun Young Hong, Wan Kyunn Whang, Taesun Park
This study aimed to examine the protective effect of Artemisia iwayomogi extract (AI) against hypertriglyceridemia induced by a high-fat diet (HFD) in mice and to uncover the underlying molecular mechanisms. C57BL/6N mice were fed chow, HFD, HFD + 0.1% AI, HFD + 0.25% AI, or HFD + 0.5% AI for 10 weeks. The addition of 0.25% and 0.5% AI resulted in dose-dependent improvements in the major parameters of hypertriglyceridemia, including plasma triglyceride, free fatty acids, apolipoprotein B, and lipoprotein lipase, with parallel reductions in body weight gain, hepatic lipid accumulation, and insulin resistance...
August 12, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28805665/the-role-of-solvent-accessible-leu-208-of-cold-active-pseudomonas-fluorescens-strain-ams8-lipase-in-interfacial-activation-substrate-accessibility-and-low-molecular-weight-esterification-in-the-presence-of-toluene
#13
Norhayati Yaacob, Nor Hafizah Ahmad Kamarudin, Adam Thean Chor Leow, Abu Bakar Salleh, Raja Noor Zaliha Raja Abd Rahman, Mohd Shukuri Mohamad Ali
The alkaline cold-active lipase from Pseudomonas fluorescens AMS8 undergoes major structural changes when reacted with hydrophobic organic solvents. In toluene, the AMS8 lipase catalytic region is exposed by the moving hydrophobic lid 2 (Glu-148 to Gly-167). Solvent-accessible surface area analysis revealed that Leu-208, which is located next to the nucleophilic Ser-207 has a focal function in influencing substrate accessibility and flexibility of the catalytic pocket. Based on molecular dynamic simulations, it was found that Leu-208 strongly facilitates the lid 2 opening via its side-chain...
August 12, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28805277/two-dimensional-physical-gels-can-exist-even-at-zero-surface-pressure-at-the-air-water-interface-rheology-of-self-assembled-domains-of-small-molecules
#14
Mariam Veschgini, Taichi Habe, Salomé Mielke, Shigeto Inoue, Xianhe Liu, Marie Pierre Krafft, Motomu Tanaka
Films of mesoscopic domains self-assembled from fluorocarbon/hydrocarbon diblocks (FnHm) at the air/water interface were found to display highly elastic behavior. We determined the interfacial viscoelasticity of domain-patterned FnHm Langmuir monolayers by applying periodic shear stresses. Remarkably, we found the formation of two-dimensional gels even at zero surface pressure. These monolayers are predominantly elastic, which is unprecedented for surfactants, exhibiting gelation only at high surface pressures...
August 14, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28805233/analytic-and-dynamic-secretory-profile-of-patient-derived-cytokine-induced-killer-cells
#15
Giulia Mesiano, Roberta Zini, Giulia Montagner, Nicoletta Bianchi, Rossella Manfredini, Antonella Chillemi, Massimo Aglietta, Giovanni Grignani, Ilaria Lampronti, Erika Fiorino, Fabio Malavasi, Dario Sangiolo, Roberto Gambari, Davide Ferrari
Adoptive immunotherapy with Cytokine Induced Killer (CIK) cells has shown antitumor activity against several kinds of cancers in preclinical models and clinical trials. CIK cells are a subset of ex vivo expanded T lymphocytes with T-NK phenotype and MHC-unrestricted antitumor activity. Literature provides scanty information on cytokines, chemokines and growth factors secreted by CIK cells. Therefore, we investigated the secretory profile of CIK cells generated from tumor patients. The secretome analysis was performed at specific time points (day 1, day 14 and day 21) of CIK cells expansion...
August 9, 2017: Molecular Medicine
https://www.readbyqxmd.com/read/28805061/a-triple-helix-molecular-switch-electrochemical-ratiometric-biosensor-for-ultrasensitive-detection-of-nucleic-acids
#16
Erhu Xiong, Zhenzhen Li, Xiaohua Zhang, Jiawan Zhou, Xiaoxia Yan, Yunqing Liu, Jinhua Chen
Biomolecular receptors such as nucleic acids that switch between two or more conformations upon binding to a specific target can be used to build specific and sensitive biosensors. In this work, based on the electrochemical dual-signaling ratiometric strategy and triple-helix molecular switch, we developed a selective, reusable, and simple electrochemical DNA (E-DNA) biosensor for target DNA (T-DNA) detection. A hairpin DNA capture probe labeled with methylene blue (MB-DNA) self-assembles on the surface of gold electrode (GE) through Au-S bond, and then a single-strand DNA modified with two ferrocenes (Fc-DNA) on each end to enhance the oxidation signal hybridizes with the MB-DNA to form a triple-helix conformation...
August 14, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28805040/hpma-copolymer-drug-conjugates-with-controlled-tumor-specific-drug-release
#17
REVIEW
Petr Chytil, Eva Koziolová, Tomáš Etrych, Karel Ulbrich
Over the past few decades, numerous polymer drug carrier systems are designed and synthesized, and their properties are evaluated. Many of these systems are based on water-soluble polymer carriers of low-molecular-weight drugs and compounds, e.g., cytostatic agents, anti-inflammatory drugs, or multidrug resistance inhibitors, all covalently bound to a carrier by a biodegradable spacer that enables controlled release of the active molecule to achieve the desired pharmacological effect. Among others, the synthetic polymer carriers based on N-(2-hydroxypropyl) methacrylamide (HPMA) copolymers are some of the most promising carriers for this purpose...
August 14, 2017: Macromolecular Bioscience
https://www.readbyqxmd.com/read/28804965/synthetic-manipulation-of-hybrid-perovskite-systems-in-search-of-novel-and-enhanced-functionalities
#18
Rounak Naphade, Satyawan Nagane, Umesh Bansode, Mukta Tathavadekar, Aditya Sadhanala, Satishchandra B Ogale
Over the past few years the organic/Inorganic hybrid perovskite systems have emerged as a promising class of materials for photo-voltaic and electroluminescent thin film device applications, in view of their unique set of tunable optoelectronic properties. Importantly, these materials can be easily solution-processed at low temperatures and as such are amenable to facile molecular engineering. Thus, a variety of low dimensional forms and quantum structures of these materials can be obtained through strategic synthetic manipulations via small molecule incorporation or molecular ion doping...
August 13, 2017: ChemSusChem
https://www.readbyqxmd.com/read/28804832/measuring-direct-oral-anticoagulants
#19
Robert C Gosselin, Jonathan Douxfils
Direct oral anticoagulants (DOACs) can be quantified using methods that can be performed in any clinical or research laboratory using manual or automated instrument platforms. Dabigatran etexilate, the oral direct thrombin inhibitor, can be quantified by drug-calibrated clot or chromogenic-based assays using either thrombin or ecarin as substrates. Oral direct anti-Xa inhibitors, such as rivaroxaban, apixaban, and edoxaban, can be quantified with drug-calibrated anti-Xa kits or reagents as typically used for measuring heparins (unfractionated, low molecular weight, or pentasaccharides)...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28804479/molecular-characterization-of-arbuscular-mycorrhizal-fungi-in-an-agroforestry-system-reveals-the-predominance-of-funneliformis-spp-associated-with-colocasia-esculenta-and-pterocarpus-officinalis-adult-trees-and-seedlings
#20
Alexandre Geoffroy, Hervé Sanguin, Antoine Galiana, Amadou Bâ
Pterocarpus officinalis (Jacq.) is a leguminous forestry tree species endemic to Caribbean swamp forests. In Guadeloupe, smallholder farmers traditionally cultivate flooded taro (Colocasia esculenta) cultures under the canopy of P. officinalis stands. The role of arbuscular mycorrhizal (AM) fungi in the sustainability of this traditional agroforestry system has been suggested but the composition and distribution of AM fungi colonizing the leguminous tree and/or taro are poorly characterized. An in-depth characterization of root-associated AM fungal communities from P...
2017: Frontiers in Microbiology
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