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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
D Funes-Hernando, M Pelaez-Fernandez, D Winterauer, J-Y Mevellec, R Arenal, T Batten, B Humbert, J L Duvail
This study reports on the plasmon-mediated remote Raman sensing promoted by specially designed coaxial nanowires. This unusual geometry for Raman study is based on the separation, by several micrometres, of the excitation laser spot, on one tip of the nanowire, and the Raman detection at the other tip. The very weak efficiency of Raman emission makes it challenging in a remote configuration. For the proof-of-concept, we designed coaxial nanowires consisting of a gold core to propagate surface plasmon polaritons and a Raman-emitting shell of poly(3,4-ethylene-dioxythiophene)...
March 22, 2018: Nanoscale
Shishu Zhang, Na Zhang, Yan Zhao, Ting Cheng, Xiaobo Li, Rui Feng, Hua Xu, Zhirong Liu, Jin Zhang, Lianming Tong
Two-dimensional (2D) layered materials have attracted tremendous attention and led to a prosperous development in both fundamental investigation and device applications in various fields, such as nanoelectronics, flexible devices, sustainable energy and catalysts. The precise characterization of the structure and properties of 2D materials is in urgent need. Raman scattering spectroscopy is one of the most popular characterization tools that is convenient, rapid and non-invasive. It provides information on both the lattice structure from the frequency of phonon modes and the electronic band structure through the intensity due to electronic resonance Raman scattering...
March 22, 2018: Chemical Society Reviews
Huayue Mei, Yuhan Zhong, Peida Wang, Zhenyuan Jia, Chunmei Li, Nanpu Cheng
The electronic, optical, and lattice dynamical properties of tetracalcium trialuminate (Ca₄Al₆O13 ) with a special sodalite cage structure were calculated based on the density functional theory. Theoretical results show that Ca₄Al₆O13 is ductile and weakly anisotropic. The calculated Young's modulus and Poisson ratio are 34.18 GPa and 0.32, respectively. Ca₄Al₆O13 is an indirect-gap semiconductor with a band gap of 5.41 eV. The top of the valence band derives from O 2 p states, and the bottom of conduction band consists of Ca 3 d states...
March 19, 2018: Materials
Antonino Foti, Cristiano D'Andrea, Valentina Villari, Norberto Micali, Maria Grazia Donato, Barbara Fazio, Onofrio M Maragò, Raymond Gillibert, Marc Lamy de la Chapelle, Pietro G Gucciardi
Optical forces are used to aggregate plasmonic nanoparticles and create SERS-active hot spots in liquid. When biomolecules are added to the nanoparticles, high sensitivity SERS detection can be accomplished. Here, we pursue studies on Bovine Serum Albumin (BSA) detection, investigating the BSA-nanorod aggregations in a range from 100 µM to 50 nM by combining light scattering, plasmon resonance and SERS, and correlating the SERS signal with the concentration. Experimental data are fitted with a simple model describing the optical aggregation process...
March 17, 2018: Materials
Shima Rahim Pouran, Abolfazl Bayrami, Mohammad Saleh Shafeeyan, Abdul Aziz Abdul Raman, Wan Mohd Ashri Wan Daud
Oxidative treatment of a cationic dye solution, methylene blue, was investigated using magnetite nanoparticles and goethite in heterogeneous Fenton-like reaction, and ferrous ions in homogeneous Fenton-reaction. The aim was to compare the degradation efficiencies of the studied catalysts for decolorization of methylene blue solution as the model organic pollutant. Response surface methodology (RSM) was applied to determine the optimal operational conditions for magnetite/H2O2 and goethite/H2O2 systems. The [H2O2] of 0...
March 2018: Acta Chimica Slovenica
Jorge Ontaneda, Anjali Singh, Umesh V Waghmare, Ricardo Grau-Crespo
Monolayers of hexagonal boron nitride (h-BN) can in principle be identified by a Raman signature, consisting of an upshift in the frequency of the E2g vibrational mode with respect to the bulk value, but the origin of this shift (intrinsic or support-induced) is still debated. Herein we use density functional theory calculations to investigate whether there is an intrinsic Raman shift in the h-BN monolayer in comparison with the bulk. There is universal agreement among all tested functionals in predicting the magnitude of the frequency shift upon a variation in the in-plane cell parameter...
March 21, 2018: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Ozgur Burak Aslan, Isha Datye, Michal J Mleczko, Karen Sze Cheung, Sergiy Krylyuk, Alina Bruma, Irina Kalish, Albert Davydov, Eric Pop, Tony F Heinz
Ultrathin transition metal dichalcogenides (TMDCs) have been recently investigated to understand their optoelectronic properties. Here we study ultrathin Mo0.91 W0.09 Te2 , a semiconducting alloy of MoTe2 , via Raman, photoluminescence (PL), and optical absorption measurements. Mo0.91 W0.09 Te2 transitions from indirect to direct optical band gap in the monolayer limit at 1.1 eV, very close to its MoTe2 counterpart. We apply tensile strain to monolayer MoTe2 and Mo0.91 W0.09 Te2 to tune their band structures for the first time, and we observe that their optical band gaps decrease by ~70 meV at ~2...
March 21, 2018: Nano Letters
Haw-Tyng Huang, Li Zhu, Matthew D Ward, Brian L Chaloux, Rostislav Hrubiak, Albert Epshteyn, John V Badding, Timothy A Strobel
The chemical stability of solid cubane under high-pressure was examined with in situ Raman spectroscopy and synchrotron powder X-ray diffraction (PXRD) in a diamond anvil cell (DAC) up to 60 GPa. The Raman modes associated with solid cubane were assigned by comparing experimental data with calculations based on density functional perturbation theory, and low-frequency lattice modes are reported for the first time. The equation of state of solid cubane derived from the PXRD measurements taken during compression gives a bulk modulus of 14...
March 21, 2018: Journal of Physical Chemistry Letters
Biwu Liu, Peng Wu, Zhicheng Huang, Lingzi Ma, Juewen Liu
Functionalization of a gold surface with DNA is often complicated by kinetic traps from unintended DNA base adsorption. Herein, we communicate that Br- serves as a robust backfilling agent displacing selected DNA bases on gold. Traditional thiol backfillers are too strong, while even 300 mM Br- is well tolerated. Conjugates prepared with Br- hybridize 10-fold faster and resist DNA release with better colloidal stability yielding highly sensitive probes. From colorimetric and Raman assays, adsorption affinity ranks as F- < T ≈ Cl- < C < G ≈ Br- < A < I- , allowing Br- to displace nonpoly-A sequences from gold...
March 22, 2018: Journal of the American Chemical Society
Wei Ji, Xue Zhang, Jianzhang Zhao, Ye Gao, Wei Song, Yukihiro Ozaki
A simple and ultrasensitive surface-enhanced Raman scattering (SERS) assay for heparin detection has been demonstrated based on an in situ hot spot assembly method using N,N'-bis[3,3'-(trimethylammonium)propylamine]-3,4,9,10-perylenediimide (bis-quaternized perylene dye, abbreviated as BQPER). In this assay, a BQPER probe with two positive charges is employed as both Raman reporter and electrostatic bridge to cause the aggregation of citrate-capped Ag nanoparticles (Ag NPs), resulting in a strong SERS signal due to the formation of numerous hot spots in the gaps of the aggregates...
March 21, 2018: Analyst
Uriel N Morzan, Diego J Alonso de Armiño, Nicolás O Foglia, Francisco Ramírez, Mariano C González Lebrero, Damián A Scherlis, Darío A Estrin
The applications of multiscale quantum-classical (QM-MM) approaches have shown an extraordinary expansion and diversification in the last couple of decades. A great proportion of these efforts have been devoted to interpreting and reproducing spectroscopic experiments in a variety of complex environments such as solutions, interfaces, and biological systems. Today, QM-MM-based computational spectroscopy methods constitute accomplished tools with refined predictive power. The present review summarizes the advances that have been made in QM-MM approaches to UV-visible, Raman, IR, NMR, electron paramagnetic resonance, and Mössbauer spectroscopies, providing in every case an introductory discussion of the corresponding methodological background...
March 21, 2018: Chemical Reviews
Ibrahim Y Ahmet, Michael S Hill, Paul R Raithby, Andrew L Johnson
A family of tin(ii) guanidinate complexes of the general form [{RNC(NMe2)NR}2Sn] (R = iPr (6), Cy (7), Tol (9) and Dipp (10)) and [{tBuNC(NMe2)NtBu}Sn{NMe2}] (8) have been synthesised and isolated from the reaction of tin(ii) bis-dimethylamide and a series of carbodiimides (1-5). The cyclic poly-chalcogenide compounds [{CyNC(NMe2)NCy}2Sn{Chx}] (Ch = S, x = 4 (11); Ch = Se, x = 4 (12), and Ch = S, x = 6 (13)) with {SnChx} rings were prepared by the oxidative addition of elemental sulfur and selenium to the heteroleptic stannylene complex [{CyNC(NMe2)NCy}2Sn] (7) in THF at room temperature...
March 21, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Tommaso Giovannini, Gianluca Del Frate, Piero Lafiosca, Chiara Cappelli
We present a computational methodology based on a polarizable Quantum Mechanical (QM)/Molecular Mechanics (MM) approach to accurately compute the Vibrational Optical Activity (VOA) spectra of chiral systems. This approach is applied for the calculation of Infrared (IR), Vibrational Circular Dichroism (VCD), Raman and Raman Optical Activity (ROA) spectra of aqueous solutions of (l)-methyl lactate and (S)-glycidol. Remarkable agreement between calculations and experiments is reported, showing the reliability and accuracy of the methodology, especially with respect to standard continuum solvation approaches...
March 21, 2018: Physical Chemistry Chemical Physics: PCCP
Yongqiang Cheng, Lijuan Dong, Jiangyan Zhang, Yaqing Zhao, Zhengping Li
The development of simple, robust, and reliable microRNA (miRNA) detection methods is of great significance in the studies of the biological function of miRNAs, molecular diagnostics, treatment of diseases, and targeted drugs. In recent years, with the increasing development of miRNA research, lots of novel approaches were developed for the detection of miRNA in terms of sensitivity, specificity, multiplicity, in situ imaging, etc. In particular, nucleic acid amplification-based methods and many detection techniques such as droplet digital PCR (ddPCR), electrochemiluminescence (ECL), surface-enhanced Raman spectroscopy (SERS), and mass spectrometry (MS) have been employed widely for the highly sensitive detection of miRNA...
March 21, 2018: Analyst
Sarre Kadia Myra Nzaba, Bulelwa Ntsendwana, Bhekie Brilliance Mamba, Alex Tawanda Kuvarega
This study examined the photocatalytic degradation of an azo dye brilliant black (BB) using non-metal/metal co-doped TiO2 . N,Pt co-doped TiO2 photocatalysts were prepared by a modified sol-gel method using amine-terminated polyamidoamine dendrimer generation 0 (PG0) as a template and source of nitrogen. Structural, morphological, and textural properties were evaluated using scanning electron microscopy coupled to energy-dispersive X-ray spectroscopy (SEM/EDX), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction spectroscopy (XRD), X-ray photoelectron spectroscopy (XPS), thermal gravimetric analysis (TGA), Fourier transform infrared (FTIR), Raman spectroscopy (RS), photoluminescence (PL) and ultra-violet/visible spectroscopy (UV-Vis)...
March 20, 2018: Environmental Science and Pollution Research International
Eric Wallace, Zachary Stewart, David Theriot, William Shaffer, Shane Guillory, Michael Hanemann, Raman Danrad, Bradley Spieler
Background: Plasmacytomas are monoclonal proliferations of plasma cells that typically affect the intramedullary axial skeleton. Imaging findings of an extramedullary plasmacytoma on radiograph and computed tomography can be nonspecific and can resemble other entities such as lymphoma, metastases, chondrosarcomas, or giant cell tumors. Case Report: A 60-year-old female with a medical history of partial complex seizures, hypertension, diabetes, glaucoma, and hyperlipidemia presented with complaints of superficial abdominal pain associated with erythema and swelling for 3 weeks...
2018: Ochsner Journal
Marcelo Souto Nacif, Fabio S Raman, Neville Gai, Jacquin Jones, Rob J van der Geest, Christopher T Sibley, Songtao Liu, A Bluemke David
Objective: To compare an albumin-bound gadolinium chelate (gadofosveset trisodium) and an extracellular contrast agent (gadobenate dimeglumine), in terms of their effects on myocardial longitudinal (T1) relaxation time and partition coefficient. Materials and Methods: Study subjects underwent two imaging sessions for T1 mapping at 3 tesla with a modified look-locker inversion recovery (MOLLI) pulse sequence to obtain one pre-contrast T1 map and two post-contrast T1 maps (mean 15 and 21 min, respectively)...
January 2018: Radiologia Brasileira
Khan Behlol Ayaz Ahmed, Thiagarajan Raman, Anbazhagan Veerappan
A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.
March 20, 2018: Scientific Reports
Maxim Karpov, Martin H P Pfeiffer, Junqiu Liu, Anton Lukashchuk, Tobias J Kippenberg
Dissipative Kerr solitons (DKS) in optical microresonators provide a highly miniaturised, chip-integrated frequency comb source with unprecedentedly high repetition rates and spectral bandwidth. To date, such frequency comb sources have been successfully applied in the optical telecommunication band for dual-comb spectroscopy, coherent telecommunications, counting of optical frequencies and distance measurements. Yet, the range of applications could be significantly extended by operating in the near-infrared spectral domain, which is a prerequisite for biomedical and Raman imaging applications, and hosts commonly used optical atomic transitions...
March 20, 2018: Nature Communications
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