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Raman spectra

Phiranuphon Meksiarun, Mika Ishigaki, Verena A C Huck-Pezzei, Christian W Huck, Kanet Wongravee, Hidetoshi Sato, Yukihiro Ozaki
This study aimed to extract the paraffin component from paraffin-embedded oral cancer tissue spectra using three multivariate analysis (MVA) methods; Independent Component Analysis (ICA), Partial Least Squares (PLS) and Independent Component - Partial Least Square (IC-PLS). The estimated paraffin components were used for removing the contribution of paraffin from the tissue spectra. These three methods were compared in terms of the efficiency of paraffin removal and the ability to retain the tissue information...
March 22, 2017: Scientific Reports
Jeffrey W Slater, Sean C Marguet, Sabrina L Cirino, Pearson T Maugeri, Hannah S Shafaat
Nickel-substituted rubredoxin (NiRd) is a functional enzyme mimic of hydrogenase, highly active for electrocatalytic and solution-phase hydrogen generation. Spectroscopic methods can provide valuable insight into the catalytic mechanism, provided the appropriate technique is used. In this study, we have employed multiwavelength resonance Raman spectroscopy coupled with DFT calculations on an extended active-site model of NiRd to probe the electronic and geometric structures of the resting state of this system...
March 21, 2017: Inorganic Chemistry
C X Zhang, X G Qiu
Parity anomaly refers to the violation of coordinate reflection symmetry induced by the quantum fluctuations. It is proposed to exist in a graphene-like system with a finite bare mass for Dirac fermions, and manifests itself as a parity- violating quantum correction to the current of each species of fermions. Coulomb interaction greatly increases the fermion mass, and produces various types of excitons. Of particular interest is the ρ-exciton, which is directly connected to parity anomaly and can be generated by absorbing a specific photon...
March 21, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Alicia Schirer, Youssef El Khoury, Peter Faller, Petra Hellwig
GHK and DAHK are biological peptides that bind both copper and zinc cations. Here we used infrared and Raman spectroscopies to study the coordination modes of both copper and zinc ions, at pH 6.8 and 8.9, correlating the data with the crystal structures that are only available for the copper-bound form. We found that Cu(II) binds to deprotonated backbone (amidate), the N-terminus and N(π) of the histidine side chain, in both GHK and DAHK, at pH 6.8 and 8.9. The data for the coordination of zinc at pH 6.8 points to two conformers including both nitrogens of a histidine residue...
March 20, 2017: Journal of Biological Inorganic Chemistry: JBIC
K M Muhammed Shameem, Khoobaram S Choudhari, Aseefhali Bankapur, Suresh D Kulkarni, V K Unnikrishnan, Sajan D George, V B Kartha, C Santhosh
Classification of plastics is of great importance in the recycling industry as the littering of plastic wastes increases day by day as a result of its extensive use. In this paper, we demonstrate the efficacy of a combined laser-induced breakdown spectroscopy (LIBS)-Raman system for the rapid identification and classification of post-consumer plastics. The atomic information and molecular information of polyethylene terephthalate, polyethylene, polypropylene, and polystyrene were studied using plasma emission spectra and scattered signal obtained in the LIBS and Raman technique, respectively...
March 20, 2017: Analytical and Bioanalytical Chemistry
Sylwia Zięba, Adam Mizera, Katarzyna Pogorzelec-Glaser, Andrzej Łapiński
Imidazolium selenate dihydrate (ImH2)2SeO4·2H2O crystals have been investigated using Raman and IR spectroscopy. Experimental data were supported by the quantum-chemical calculations (DFT), Hirshfield surfaces and fingerprint plots analysis, and Bader theory calculations. The imidazolium selenate dihydrate crystal exhibits high proton conductivity of the order of ~10(-1)S/m at T=333K. The spectra of this compound are dominated by bands related to the lattice modes, the internal vibrations of the protonated imidazole cation, selenate anion, water molecules, and hydrogen bonds network...
February 28, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
V Kavelin, O Fesenko, H Dubyna, C Vidal, T A Klar, C Hrelescu, L Dolgov
Sulfonated Zn phthalocyanine, as a prospective photosensitizer in the photodynamic therapy of tumors, is investigated by means of Raman, infrared, and fluorescence spectroscopies. Conventional and surface-enhanced spectra from this photosensitizer are obtained and compared. Gold nano-islands attached to silica cores (Au-SiO2) are proposed as nanostructures providing plasmonically enhanced signals. Pronounced enhancement of Raman and infrared spectral bands from sulfonated Zn phthalocyanine allows their more convenient assignment with vibrational modes of sulfonated Zn phthalocyanine...
December 2017: Nanoscale Research Letters
Michael T Ruggiero, J Axel Zeitler, Alessandro Erba
The intermolecular anharmonic potential of crystalline purine is probed by means of temperature-dependent terahertz time-domain spectroscopy, low-frequency Raman scattering, X-ray diffraction, and ab initio quasi-harmonic quantum-chemical simulations. As temperature increases, anharmonicity in the intermolecular interactions results in strongly anisotropic thermal expansion - with a negative thermal expansion along the b crystallographic axis - yielding corresponding bulk structural modifications. The observed thermally-induced shifts of most vibrational bands in the terahertz region of the spectra are shown to arise from volume-dependent thermal changes of the hydrogen-bond pattern along the a and b crystallographic axes...
March 17, 2017: Chemical Communications: Chem Comm
Aurea Bernardino-Nicanor, Gerardo Acosta-García, Norma Güemes-Vera, José Luis Montañez-Soto, María de Los Ángeles Vivar-Vera, Leopoldo González-Cruz
Starches isolated from four ayocote bean varieties were modified by thermal treatment to determinate the effect of the treatment on the structural changes of ayocote bean starch. Scanning electron microscopy indicates that the starch granules have oval and round shapes, with heterogeneous sizes and fractures when the extraction method is used. The presence of new bands at 2850 and 1560 cm(-1) in the FT-IR spectra showed that the thermal treatment of ayocote beans induced an interaction between the protein or lipid and the amylose or amylopectin, while the sharpest band at 3400 cm(-1) indicated a dehydration process in the starch granule in addition to the presence of the band at 1260 cm(-1), indicating the product of the retrogradation process...
March 2017: Journal of Food Science and Technology
Kengo Saito, Qiling Peng, Lin Qiao, Lin Wang, Tatsuya Joutsuka, Tatsuya Ishiyama, Shen Ye, Akihiro Morita
Sum frequency generation (SFG) spectroscopy is widely used to observe molecular orientation at interfaces through a combination of various types of polarization. The present work thoroughly examines the relation between the polarization dependence of SFG signals and the molecular orientation, by comparing SFG measurements and molecular dynamics (MD) simulations of acetonitrile/water solutions. The present SFG experiment and MD simulations yield quite consistent results on the ratios of χ((2)) elements, supporting the reliability of both means...
March 16, 2017: Physical Chemistry Chemical Physics: PCCP
Ondrej Marsalek, Thomas E Markland
Understanding the reactivity and spectroscopy of aqueous solutions at the atomistic level is crucial for the elucidation and design of chemical processes. However, the simulation of these systems requires addressing the formidable challenges of treating the quantum nature of both the electrons and nuclei. Exploiting our recently developed methods that provide acceleration by up to 2 orders of magnitude, we combine path integral simulations with on-the-fly evaluation of the electronic structure at the hybrid density functional theory level to capture the interplay between nuclear quantum effects and the electronic surface...
March 22, 2017: Journal of Physical Chemistry Letters
Zeng Fan, Donghe Du, Hongyan Yao, Jianyong Ouyang
Poly(3,4-ethylenedioxuthiphene):poly(styrenesulfonate) (PEDOT:PSS) is a promising candidate as the next-generation thermoelectric (TE) material. Its TE properties are strongly dependent on its chemical and electronic structures. In this paper, we investigated the effect of PEDOT molecular weight on the TE properties of PEDOT:PSS films by a comparative study on two commercial grades of PEDOT:PSS, CleviosTM P and CleviosTM PH1000. Dynamic light scattering (DLS) and Raman spectra imply that the PEDOT of CleviosTM PH1000 possesses longer conjugated chains than that of CleviosTM P...
March 15, 2017: ACS Applied Materials & Interfaces
Shuhei Yoshida, Ya Feng, Clement Delacou, Taiki Inoue, Rong Xiang, Reo Kometani, Shohei Chiashi, Esko Kauppinen, Shigeo Maruyama
The thermal transport properties of random-network, single-walled carbon nanotube (SWNT) films were assessed using Raman spectroscopy. Two types of SWNT films were investigated: single-layer and stacked. The single-layer films were fabricated by aerosol chemical vapour deposition and subsequent direct dry-deposition, while the stacked films were prepared by placing the single-layer films on top of one another. The anisotropy of the network structures of each of these films was evaluated based on the angular dependence of the optical absorbance spectra...
March 14, 2017: Nanotechnology
Luciana C Juncal, José Avila, Maria Carmen Asensio, Carlos O Della Védova, Rosana M Romano
The electronic properties of the coordination complex nickel (II) bis-n-propylxanthate, Ni(CH3(CH2)2OC(S)S)2, were studied by a combination of complementary experimental (both laboratory and synchrotron based techniques) and theoretical methods. Energy differences between HOMOs and LUMOs were determined from UV-visible spectroscopy. The assignment of the transitions were performed with the aid of TD-DFT calculations and based in symmetry considerations. The analysis of the Raman excitation profiles of selected vibrational modes of the complex, taken in resonance with a particular electronic transition, was found to reinforce the electronic assignment...
March 3, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Yaxin Guo, Jie Wei, Yalong Liu, Tiantian Yang, Zhuo Xu
Cu2ZnSnS4 (CZTS) hierarchical microstructures were synthesized by using a facile and nontoxic hydrothermal route, which were characterized by X-ray powder diffraction (XRD), scanning electron microscope (SEM), Raman spectra, and UV-Vis absorption spectra. The results and analysis show that surfactants used in the hydrothermal process have significant effect on the phase structures, morphologies, and photocatalytic activities of CZTS powders. Especially, the well-crystallized and pure kesterite CZTS hierarchical microstructures were synthesized with the addition of high-concentration tartaric acid (TA) in the hydrothermal process...
December 2017: Nanoscale Research Letters
Wolfram W Rudolph, Gert Irmer
Raman spectra of aqueous La(3+), Ce(3+), Pr(3+), Nd(3+) and Sm(3+) - perchlorate solutions were measured and weak strongly polarized Raman bands were detected at 343 cm(-1), 344 cm(-1), 347 cm(-1), 352 cm(-1) and 363 cm(-1), respectively. The full width at half height for these bands is quite broad (∼50 cm(-1)) in the isotropic spectrum and the band width increases with increasing solute concentration. The polarized Raman bands were assigned to the breathing modes of the nona-aqua ions of the mentioned rare earth ions...
March 10, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
M Virumbrales-Del Olmo, A Delgado-Cabello, A Andrada-Chacón, J Sánchez-Benítez, E Urones-Garrote, V Blanco-Gutiérrez, M J Torralvo, R Sáez-Puche
Single domain superparamagnetic ferrite nanoparticles with the composition MFe2O4 (M = Fe, Co, Zn) have been prepared by thermal decomposition of metal acetylacetonates in diphenyl ether or dibenzyl ether, using oleic acid in the presence of oleylamine as a stabilizing agent. The Fe, Co and Zn ferrite nanoparticles are monodisperse with diameters of 4.9, 4.4 and 4.7 nm, respectively. The TG and IR results indicate that four or six carboxylate groups per nm(2) are bonded at the surface of the particles acting as chelating and/or bridging bidentate ligands depending on the composition...
March 10, 2017: Physical Chemistry Chemical Physics: PCCP
I J Jahn, O Žukovskaja, X-S Zheng, K Weber, T W Bocklitz, D Cialla-May, J Popp
The exhaustive body of literature published in the last four years on the development and application of systems based on surface-enhanced Raman spectroscopy (SERS) combined with microfluidic devices demonstrates that this research field is a current hot topic. This synergy, also referred to as lab-on-a-chip SERS (LoC-SERS) or nano/micro-optofluidics SERS, has opened the door for new opportunities where both techniques can profit. On the one hand, SERS measurements are considerably improved because the processes previously performed on a large scale in the laboratory and prone to human error can now be carried out in nanoliter volumes in an automatic and reproducible manner; on the other hand, microfluidic platforms need detection methods able to sense in small volumes and therefore, SERS is ideal for this task...
March 9, 2017: Analyst
Bao Zhang, Han Tao, Xiaoli Niu, Sai Li, Han-Qing Chen
The formation and distribution of microgel-lysozyme complexes were identified by confocal laser scanning microscope (CLSM). The structure of lysozyme in the microgel was investigated by Fourier transform infrared (FT-IR) spectroscopy and Raman spectra. In vitro release of lysozyme from the microgel-lysozyme complexes was estimated. The structure of lysozyme released from stomach juice was further evaluated by circular dichroism (CD). The CLSM images showed that microgel-lysozyme complexes was formed and the lysozyme distributed quite homogeneously over the microgel particles...
July 15, 2017: Food Chemistry
Mika Ishigaki, Kosuke Hashimoto, Hidetoshi Sato, Yukihiro Ozaki
Current research focuses on embryonic development and quality not only by considering fundamental biology, but also by aiming to improve assisted reproduction technologies, such as in vitro fertilization. In this study, we explored the development of mouse embryo and its quality based on molecular information, obtained nondestructively using Raman spectroscopy. The detailed analysis of Raman spectra measured in situ during embryonic development revealed a temporary increase in protein content after fertilization...
March 8, 2017: Scientific Reports
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