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https://www.readbyqxmd.com/read/29793170/effective-size-selection-of-mos-2-nanosheets-by-a-novel-liquid-cascade-centrifugation-influences-of-the-flakes-dimensions-on-electrochemical-and-photoelectrochemical-applications
#1
Marzieh Kajbafvala, Mansoor Farbod
Although liquid phase exfoliation is a powerful method to produce MoS2 nanosheets in large scale, but its effectiveness is limited by the diversity of produced nanosheets sizes. Here a novel approach for separation of MoS2 flakes having various lateral sizes and thicknesses based on the cascaded centrifugation has been introduced. This method involves a pre-separation step which is performed through low-speed centrifugation to avoid the deposition of large area single and few-layers by the heavier particles...
May 14, 2018: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/29793147/study-on-the-interactions-between-toxic-nitroanilines-and-lysozyme-by-spectroscopic-approaches-and-molecular-modeling
#2
Yunlan Gu, Yanqing Wang, Hongmei Zhang
Being exogenous environmental pollutants, nitroanilines (NAs) are highly toxic and have mutagenic and carcinogenic activity. Being lack of studies on interactions between NAs and lysozyme at molecular level, the binding interactions of lysozyme with o-nitroaniline (oNA), m-nitroaniline (mNA) and p-nitroaniline (pNA) were investigated by means of steady-state fluorescence, synchronous fluorescence, UV-vis absorption spectroscopy, as well as molecular modeling. The experimental results revealed that the fluorescence of lysozyme is quenched by oNA and mNA through a static quenching, while the fluorescence quenching triggered by pNA is a combined dynamic and static quenching...
May 5, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/29793146/development-of-a-novel-tridentate-ligand-for-colorimetric-detection-of-mn-2-based-on-agnps
#3
Jianyu Wei, Jinfan Chen, Guozong Yue, Liangsheng Hu, Danqing Zhao, Jing Zhu, Luming Yang, Deshun Huang, Pengxiang Zhao
A novel tridentate ligand nitrilotris(methylene)tris(1,2,3-triazole)triacetate (NTTTA) has been synthesized by click reaction and followed with ester hydrolysis reaction. The silver nanoparticles (AgNPs) were then modified and stabilized by this ligand, and subsequently been employed for the highly selective and sensitive colorimetric detection of Mn2+ in aqueous solution. The presence of Mn2+ can cause the aggregation of AgNPs, which leads to the color change of the dispersion from yellow to brown, as well as the decrease and red-shift of the surface plasmon resonance absorption...
May 9, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/29793133/an-ultrasensitive-and-selective-electrochemical-aptasensor-based-on-rgo-mwcnts-chitosan-carbon-quantum-dot-for-the-detection-of-lysozyme
#4
Behzad Rezaei, Hamid Reza Jamei, Ali Asghar Ensafi
An aptamer-based method is described for the electrochemical determination of lysozyme. A glassy carbon electrode was modified with a nanocomposite composed of reduced graphene oxide (rGO), multi-walled carbon nanotubes (MWCNTs), chitosan (CS), and a synthesized carbon quantum dot (CQD) from CS. The composition of the nanocomposite (rGO-MWCNT/CS/CQD) warrants a high surface-to-volume ratio, high conductivity, high stability, and great electrocatalytic activity. This nanocomposite provides a suitable site for better immobilization of aptamers due to the existence of many amino and carboxyl functional groups, and remaining oxygen-related defects properties in rGO...
May 9, 2018: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/29793106/microplastics-in-mussels-sampled-from-coastal-waters-and-supermarkets-in-the-united-kingdom
#5
Jiana Li, Christopher Green, Alan Reynolds, Huahong Shi, Jeanette M Rotchell
Global contamination of the marine environment by plastic has led to the discovery of microplastics in a range of marine species, including those for human consumption. In this study, the presence of microplastics and other anthropogenic debris in seawater and mussels (Mytilus edulis) from coastal waters of the U.K., as well as supermarket sources, was investigated. These were detected in all samples from all sites with spatial differences observed. Seawater samples taken from 6 locations (in triplicates) displayed 3...
May 21, 2018: Environmental Pollution
https://www.readbyqxmd.com/read/29793092/a-combined-ftir-and-dsc-study-on-the-bilayer-stabilising-effect-of-electrostatic-interactions-in-ion-paired-lipids
#6
Maximilian Schmid, Christian Wölk, Julia Giselbrecht, K L Andrew Chan, Richard D Harvey
Investigating lipid ion pair formation is important for understanding the mechanisms of lipid-mediated drug resistance in bacteria. In this study we have used the charged amphiphiles dipalmitoylphosphatidylglycerol (DPPG) and dihexadecyldimethylammonium bromide (DHDAB), as a model to evaluate the formation of ion pairs by a combined Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) analysis. FTIR was employed to study the environment of the DPPC headgroup phosphate and lipid/surfactant alkane chains, in vesicles formed by the two amphiphiles mixed in various molar ratios...
May 17, 2018: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/29793066/rapid-and-effective-removal-of-as-iii-and-as-v-using-spore-ti-4-microspheres
#7
Lijuan Lan, Bingjie Zheng, Yao Zhang, Yonggang Hu
Removing arsenic from aquatic environments has become an urgent problem worldwide. In this study, Ti4+ - loaded bacterial spore were adopted as a novel adsorbent (spore@Ti4+ microspheres) for the adsorption efficient removal of arsenite (As(III)) and arsenate (As(V)). The developed adsorbents were characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectra (FTIR) and X-ray photoelectron spectroscopy (XPS). Results indicated that the adsorption kinetics was well described by a pseudo-second-order kinetic model, and the adsorption process rapidly achieved equilibrium within 15 min at pH 7...
May 15, 2018: Chemosphere
https://www.readbyqxmd.com/read/29793061/microstructural-imaging-of-the-human-brain-with-a-super-scanner-10-key-advantages-of-ultra-strong-gradients-for-diffusion-mri
#8
D K Jones, D C Alexander, R Bowtell, M Cercignani, F Dell'Acqua, D J McHugh, K L Miller, M Palombo, G J M Parker, U S Rudrapatna, C M W Tax
The key component of a microstructural diffusion MRI 'super-scanner' is a dedicated high-strength gradient system that enables stronger diffusion weightings per unit time compared to conventional gradient designs. This can, in turn, drastically shorten the time needed for diffusion encoding, increase the signal-to-noise ratio, and facilitate measurements at shorter diffusion times. This review, written from the perspective of the National Facility for In Vivo MR Imaging of Human Tissue Microstructure, an initiative to establish a shared 300 mT/m-gradient facility amongst the microstructural imaging community, describes ten advantages of ultra-strong gradients for microstructural imaging...
May 21, 2018: NeuroImage
https://www.readbyqxmd.com/read/29793026/redistribution-of-cs-137-introduced-into-montmorillonite-in-association-with-organic-matter-coming-from-biomass-composting
#9
J Mihalik, M J Madruga, M H Casimiro, L M Ferreira, M I Prudêncio
The adsorption and later bioavailability of 137 Cs from the system humic acid (HA)/humic acid like compounds (HALC) and montmorillonite was investigated. The setup of the experiments should approach as much as possible natural conditions when 137 Cs is introduced into soil with HALC from decomposed biomass. The significant differences were found in the trials containing various HA/HALC and also pure montmorillonite. The 137 Cs was more available when it reached soil in association with HALC originated from compost than when it was adsorbed on stable humic acids...
May 16, 2018: Chemosphere
https://www.readbyqxmd.com/read/29792986/model-based-nir-spectroscopy-implementation-for-in-line-assay-monitoring-during-a-pharmaceutical-suspension-manufacturing-process
#10
Maxim Verstraeten, Daan Van Hauwermeiren, Mario Hellings, Eline Hermans, Jeroen Geens, Chris Vervaet, Ingmar Nopens, Thomas De Beer
The implementation of Process Analytical Technology (PAT) instruments is generally achieved stochastically. Sub-optimal PAT locations could introduce variation in the measurements which is not related to the analyte of interest. For this reason, rational approaches should be considered to establish an optimal sensor placement where relevant measurements are possible and the impact of disturbances is minimized. The aim of this paper is to demonstrate how mechanistic modelling can support appropriate sensor implementation by means of a case study...
May 21, 2018: International Journal of Pharmaceutics
https://www.readbyqxmd.com/read/29792966/one-step-fabrication-of-chitosan-fe-oh-3-beads-for-efficient-adsorption-of-anionic-dyes
#11
XinxinYang, Yumei Li, Hongmei Gao, Chuying Wang, Xiaohuan Zhang, Hongli Zhou
In this study, we reported the one-step synthesis of chitosan-Fe(OH)3 beads without the use of acid solvent, which could be used as effective adsorbents for anionic dyes removal. The preparation process was easy and green. The as-prepared beads were characterized for structural and morphological analysis in detail using several techniques, such as Scanning Electron Microscope, Fourier Transform Infrared Spectroscopy, X-Ray Diffraction, X-ray photoelectron spectroscopy and Thermogravimetric analysis. The content of Fe(OH)3 in chitosan-Fe(OH)3 beads was 54...
May 21, 2018: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/29792964/a-family-30-glucurono-xylanase-from-bacillus-subtilis-lc9-expression-characterization-and-its-application-in-chinese-bread-making
#12
Yalan Guo, Zhen Gao, Jiaxing Xu, Siyuan Chang, Bin Wu, Bingfang He
A GH30-8 endoxylanase was identified from an environmental Bacillus subtilis isolate following growth selection on aspen wood glucuronoxylan. The putative endoxylanase was cloned for protein expression and characterization in the Gram-positive protease deficient protein expression host B. subtilis WB800. The extracellular activity obtained was 55 U/mL, which was 14.5-fold higher than that obtained with the native species. The apparent molecular mass of BsXyn30 was estimated as 43 kDa by SDS-PAGE. BsXyn30 showed an optimal activity at pH 7...
May 21, 2018: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/29792811/tandem-mass-spectrometry-of-peptide-ions-by-microwave-excited-hydrogen-and-water-plasmas
#13
Yuji Shimabukuro, Hidenori Takahashi, Shinichi Iwamoto, Koichi Tanaka, Motoi Wada
A thermal cracking cell that served as the atomic hydrogen source for hydrogen attachment/abstraction dissociation (HAD) analysis has an intrinsic problem to produce a beam of atoms reactive against heated tungsten capillary. A plasma excited by 2.45 GHz microwave power can deliver reactive species to a quadrupole ion trap confining analyte ions without excessive heating of the radical source components. The radical (H•) production performance of the developed source was evaluated by optical emission spectroscopy and H• attachment reaction to fullerene ions...
May 24, 2018: Analytical Chemistry
https://www.readbyqxmd.com/read/29792806/fate-of-fluorescence-labels-their-adsorption-and-desorption-kinetics-to-silver-nanoparticles
#14
Claudia Kästner, Linda Böhmert, Albert Braeuning, Alfonso Lampen, Andreas F Thünemann
Silver nanoparticles are among the most widely used und produced nanoparticles. Due to their frequent application in consumer products, the assessment of their toxicological potential has seen a renewed importance. A major difficulty is the traceability of nanoparticles in in vitro and in vivo experiments. Even if the particles are labeled, for example by a fluorescent marker, the dynamic exchange of ligands often prohibits their spatial localization. Our study provides an insight into the adsorption and desorption kinetics of two different fluorescent labels on silver nanoparticles with a core radius of 3 nm by dynamic light scattering (DLS), small-angle X-ray scattering (SAXS) and fluorescence spectroscopy...
May 24, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/29792710/measuring-the-adhesion-forces-for-the-multivalent-binding-of-vancomycin-conjugated-dendrimer-to-bacterial-cell-wall-peptide
#15
Elizabeth Peterson, Christine Joseph, Hannah Peterson, Rachael Bouwman, Shengzhuang Tang, Jayme Cannon, Kumar Sinniah, Seok Ki Choi
Multivalent ligand-receptor interaction provides the fundamental basis for the hypothetical notion that high binding avidity relates to the strong force of adhesion. Despite its increasing importance in the design of targeted nanoconjugates, an understanding of the physical forces underlying the multivalent interaction remains a subject of urgent investigation. In this study, we designed three vancomycin (Van)-conjugated dendrimers G5(Van)n (n = mean valency = 0, 1, 4) for bacterial targeting with generation 5 (G5) poly(amidoamine) dendrimer as a multivalent scaffold, and evaluated both their binding avidity and physical force of adhesion to a bacterial model surface by employing surface plasmon resonance (SPR) spectroscopy and atomic force microscopy (AFM)...
May 24, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/29792706/adaptable-detection-strategies-in-membrane-based-immunoassays-calibration-free-quantitation-with-surface-enhanced-raman-scattering-readout
#16
Aleksander Skuratovsky, Robert J Soto, Marc D Porter
This paper presents a method for immunometric biomarker quantitation that uses standard flow-through assay reagents and obviates the need for constructing a calibration curve. The approach relies on a nitrocellulose immunoassay substrate with multiple physical addresses for analyte capture, each modified with different amounts of an analyte-specific capture antibody. As such, each address generates a distinctly different readout signal that is proportional to the analyte concentration in the sample. To establish the feasibility of this concept, equations derived from antibody-antigen binding equilibrium were first applied in modeling experiments...
May 24, 2018: Analytical Chemistry
https://www.readbyqxmd.com/read/29792688/rhodium-complexes-bearing-palp-pincer-ligands
#17
Naofumi Hara, Teruhiko Saito, Kazuhiko Semba, Nishamol Kuriakose, Hong Zheng, Shigeyoshi Sakaki, Yoshiaki Nakao
We report rhodium complexes bearing PAlP pincer ligands with an X-type alumanyl moiety. IR spectroscopy and single-crystal X-ray diffraction analysis of a carbonyl complex exhibit the considerable σ-donating ability of the alumanyl ligand, whose Lewis acidity is confirmed through coordination of pyridine to the aluminum center. The X-type PAlP-Rh complexes catalyze C2-selective mono-alkylation of pyridine with alkenes.
May 24, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29792687/co-mobility-of-gabarap-and-phosphatidylinositol-4-kinase-2a-on-cytoplasmic-vesicles
#18
Yan Chen, Hui-Qiao Sun, John P Eichorst, Joseph P Albanesi, Helen Yin, Joachim D Mueller
We previously reported that recruitment of the Type IIA phosphatidylinositol 4-kinase (PI4K2A) to autophagosomes by GABARAP, a member of the Atg8 family of autophagy-related proteins, is important for autophagosome-lysosome fusion. Because both PI4K2A and GABARAP have also been implicated in the intracellular trafficking of plasma membrane receptors in the secretory/endocytic pathway, we characterized their interaction in cells under non-autophagic conditions. Fluorescence fluctuation spectroscopy measurements revealed that GABARAP exists predominantly as a cytosolic monomer in live cells, but is recruited to small cytoplasmic vesicles upon overexpression of PI4K2A...
May 24, 2018: Biochemistry
https://www.readbyqxmd.com/read/29792682/calix-4-arene-based-redox-sensitive-molecular-probe-for-sers-guided-recognition-of-labile-iron-pool-in-tumor-cells
#19
Padincharapad Sreedevi, Jyothi B Nair, Preethanuj Preethalayam, Benadicta S Jeeja, Cherumuttathu H Suresh, Kaustabh Kumar Maiti, Ramavarma Luxmi Varma
Targeting the intracellular 'labile' iron pool is turned as a key modulator for cancer progression since the former is responsible for several pathological processes in tumor cells. Herein, we report a non- fluorescent calix[4]arene based triazole appended molecular probe (PTBC) for redox-specific detection of Fe3+ under physiological condition by UV-vis, FT-IR, 1H NMR, HR-MS spectroscopies, ITC and the binding strategy between Calix[4]arene and Fe3+ was modeled by DFT calculations. As a new insight PTBC probe showed significant Raman fingerprint through surface enhanced Raman scattering (SERS) modality revealing the ultrasensitive detection of Fe3+ with a LOD of 2 nM...
May 24, 2018: Analytical Chemistry
https://www.readbyqxmd.com/read/29792675/electron-phonon-coupling-and-resonant-relaxation-from-1d-and-1p-states-in-pbs-quantum-dots
#20
Eric R Kennehan, Grayson S Doucette, Ashley R Marshall, Christopher Grieco, Kyle T Munson, Matthew C Beard, John B Asbury
Observations of the hot-phonon bottleneck, which is predicted to slow the rate of hot carrier cooling in quantum confined nanocrystals, have been limited to date for reasons that are not fully understood. We used time-resolved infrared spectroscopy to directly measure higher energy intraband transitions in PbS colloidal quantum dots. Direct measurements of these intraband states permitted detailed analysis of the electronic overlap of the quantum confined states that may influence their relaxation processes...
May 24, 2018: ACS Nano
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