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Raman crystallinity

Oscar Cabeza, Luisa Segade, Montserrat Domínguez-Pérez, Esther Rilo, David Ausín, Anna Martinelli, Negin Yaghini, Bernhard Gollas, Manfred Kriechbaum, Olga Russina, Alessandro Triolo, Elena López-Lago, Luis M Varela
This paper extends the study of the induced temperature change in the mesostructure and in the physical properties occurring in aqueous mixtures of the ionic liquid 1-ethyl-3-methyl imidazolium octyl-sulfate [EMIm][OSO4 ]. For some compositions, these mixtures undergo a phase transition between the liquid (isotropic in the mesoscale) and the mesomorphic state (lyotropic liquid crystalline) at about room temperature. The behavior of mixtures doped with a divalent metal sulfate was investigated in order to observe their applicability as electrolytes...
March 14, 2018: Physical Chemistry Chemical Physics: PCCP
Agnieszka Kamińska, Tomasz Szymborski, Tomasz Jaroch, Adam Zmysłowski, Arkadiusz Szterk
Surface-enhanced Raman spectroscopy (SERS) has been widely used in a variety of biomedical, analytical, forensic and environmental investigations due to its chemical specificity, label-free nature combined with high sensitivity. Here, we report a simple method for the fabrication of reproducible and reliable, well-defined, stable SERS substrates with uniform and giant Raman enhancement suitable for routine trace chemical analysis and detection of biological compounds in complex biological fluids. We prepared porous silicone (PS) surface by a galvanostatic anodic etch of crystalline silicon wafers...
March 1, 2018: Materials Science & Engineering. C, Materials for Biological Applications
Mandy Quade, Matthias Schumacher, Anne Bernhardt, Anja Lode, Marian Kampschulte, Andrea Voß, Paul Simon, Ortrud Uckermann, Matthias Kirsch, Michael Gelinsky
The present study describes the development and characterization of strontium(II)-modified biomimetic scaffolds based on mineralized collagen type I as potential biomaterial for the local treatment of defects in systemically impaired (e.g. osteoporotic) bone. In contrast to already described collagen/hydroxyapatite nanocomposites calcium was substituted with strontium to the extent of 25, 50, 75 and 100mol% by substituting the CaCl2 -stock solution (0.1M) with SrCl2 (0.1M) during the scaffold synthesis. Simultaneous fibrillation and mineralization of collagen led to the formation of collagen-mineral nanocomposites with mineral phases shifting from nanocrystalline hydroxyapatite (Sr0) over poorly crystalline Sr-rich phases towards a mixed mineral phase (Sr100), consisting of an amorphous strontium phosphate (identified as Collin's salt, Sr6 H3 (PO4 )5 ∗2 H2 O, CS) and highly crystalline strontium hydroxyapatite (Sr5 (PO4 )3 OH, SrHA)...
March 1, 2018: Materials Science & Engineering. C, Materials for Biological Applications
Kei Hashimoto, Soma Suzuki, Morgan L Thomas, Toshihiko Mandai, Seiji Tsuzuki, Kaoru Dokko, Masayoshi Watanabe
The phase behavior of binary mixtures of triglyme (G3) and Mg[TFSA]2 (TFSA: bis(trifluoromethanesulfonyl)amide) was investigated, towards the development of a Mg2+ -based room-temperature solvate ionic liquid (SIL) electrolyte. In a 1 : 1 molar ratio, G3 and Mg[TFSA]2 form a thermally stable complex (decomposition temperature, Td : 240 °C) with a melting point (Tm ) of 70 °C, which is considerably lower than that of the analogous tetraglyme (G4) system (137 °C). X-ray crystallography of a single crystal of [Mg(G3)][TFSA]2 revealed that a single Mg2+ cation is coordinated by a single, distorted, tetradentate G3 molecule from one side, and two monodentate [TFSA]- anions, with transoid conformation, from the reverse side to form an ion pair...
March 7, 2018: Physical Chemistry Chemical Physics: PCCP
Michael J Newman, Emily M Speller, Jérémy Barbé, Joel Luke, Meng Li, Zhe Li, Zhao-Kui Wang, Sagar M Jain, Ji-Seon Kim, Harrison Ka Hin Lee, Wing Chung Tsoi
Solution-processed organic small molecule solar cells (SMSCs) have achieved efficiency over 11%. However, very few studies have focused on their stability under illumination and the origin of the degradation during the so-called burn-in period. Here, we studied the burn-in period of a solution-processed SMSC using benzodithiophene terthiophene rhodamine:[6,6]-phenyl C71 butyric acid methyl ester (BTR:PC71 BM) with increasing solvent vapour annealing time applied to the active layer, controlling the crystallisation of the BTR phase...
2018: Science and Technology of Advanced Materials
Hao-Ting Chin, Jian-Jhang Lee, Mario Hofmann, Ya-Ping Hsieh
Chemical vapor deposition (CVD) is promising for the large scale production of graphene and other two-dimensional materials. Optimization of the CVD process for enhancing their quality is a focus of ongoing effort and significant progress has been made in decreasing the defectiveness associated with grain boundaries and nucleation spots. However, little is known about the quality and origin of structural defects in the outgrowing lattice which are present even in single-crystalline material and represent the limit of current optimization efforts...
March 6, 2018: Scientific Reports
Szu-Hsuan Lee, Vardan Galstyan, Andrea Ponzoni, Isabel Gonzalo Juan, Ralf Riedel, Marie-Anne Dourges, Yohann Nicolas, Thierry Toupance
Tin dioxide (SnO2) nanoparticles were straightforwardly synthesized using an easily scaled-up liquid route that involves the hydrothermal treatment, either under acidic or basic conditions, of a commercial tin dioxide particle suspension including potassium counter-ions. After further thermal post-treatment, the nanomaterials have been thoroughly characterized by FTIR and Raman spectroscopy, powder X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and nitrogen sorption porosimetry...
March 5, 2018: ACS Applied Materials & Interfaces
A Raja, S Ashokkumar, R Pavithra Marthandam, J Jayachandiran, Chandra Prasad Khatiwada, K Kaviyarasu, R Ganapathi Raman, M Swaminathan
The present work reports the green synthesis of Zinc Oxide Nanoparticles (ZnO NPs) using aqueous Tabernaemontana divaricata green leaf extract. ZnO NPs have been characterized by X-ray diffraction (XRD), Ultra Violet-Visible (UV-Vis) studies, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Fourier Transform-Infra Red (FT-IR) analysis. XRD pattern analysis confirms the presence of pure hexagonal wurtzite crystalline structure of ZnO. The TEM images reveal the formation of spherical shape ZnO NPs with the sizes ranging from 20 to 50 nm...
February 8, 2018: Journal of Photochemistry and Photobiology. B, Biology
S Chauhan, S A Khan, A Prasad
The present study investigates Raman scattering of human bone irradiated with 50 Gy single dose during therapeutic treatment of Ewing and Osteosarcoma. Bone quality was evaluated via mineral-to-matrix ratio, degree of crystallinity, change in amount of calcium, and carbonate substitution. Alteration in collagen and its cross-links was quantified through second-derivative deconvolution of Amide I peak. A dose of 50 Gy radiation leads to almost 50% loss of mineral content, while maintaining mineral crystallinity, and small changes in carbonate substitution...
March 2, 2018: Calcified Tissue International
A Fasanella, K Cosentino, A Beneduci, G Chidichimo, E Cazzanelli, R C Barberi, M Castriota
Many cell membranes of living organisms can be represented as phospholipid bilayers immersed into a water environment. The physical-chemical interactions at the membranes/water interface are responsible for the stabilization of the membranes. In addition, the drug efficiency, the pharmaceutical mechanism and the improvement of the drug design can be addressed to the interactions between the membranes-water interface with the drug and to the membrane-drug interface. In this framework, it is important to find membranes models able to simulate and simultaneously simplify the biological systems to better understand both physical and chemical interactions at the interface level...
February 27, 2018: Biochimica et Biophysica Acta
Ali Bumajdad, Ahmed Abdel Nazeer, Fakhreia Al Sagheer, Shamsun Nahar, Mohamed I Zaki
In this investigation, well defined mesoporous zirconia nanoparticles (ZrO2 NPs) with cubic, tetragonal or monoclinic pure phase were synthesized via thermal recovery (in air) from chitosan (CS)- or polyvinyl alcohol (PVA)-ZrOx hybrid films, prepared using sol-gel processing. This facile preparative method was found to lead to an almost quantitative recovery of the ZrOx content of the film in the form of ZrO2 NPs. Impacts of the thermal recovery temperature (450, 800 and 1100 °C) and polymer type (natural bio-waste CS or synthetic PVA) used in fabricating the organic/inorganic hybrid films on bulk and surface characteristics of the recovered NPs were probed by means of X-ray diffractometry and photoelectron spectroscopy, FT-IR and Laser Raman spectroscopy, transmission electron and atomic force microscopy, and N2 sorptiometry...
February 27, 2018: Scientific Reports
Matthew D Ward, Haw-Tyng Huang, Li Zhu, Arani Biswas, Dmitry Popov, John V Badding, Timothy A Strobel
The 1 : 1 acetylene-benzene cocrystal, C2 H2 ·C6 H6 , was synthesized under pressure in a diamond anvil cell (DAC) and its evolution under pressure was studied with single-crystal X-ray diffraction and Raman spectroscopy. C2 H2 ·C6 H6 is stable up to 30 GPa, nearly 10× the observed polymerization pressure for molecular acetylene to polyacetylene. Upon mild heating at 30 GPa, the cocrystal was observed to undergo an irreversible transition to a mixture of amorphous hydrocarbon and a crystalline phase with similar diffraction to i-carbon, a nanodiamond polymorph currently lacking a definitive structure...
February 27, 2018: Physical Chemistry Chemical Physics: PCCP
Pei-Jiang Wang, Nicola Ferralis, Claire Conway, Jeffrey C Grossman, Elazer R Edelman
Polymer-based bioresorbable scaffolds (BRS) seek to eliminate long-term complications of metal stents. However, current BRS designs bear substantially higher incidence of clinical failures, especially thrombosis, compared with metal stents. Research strategies inherited from metal stents fail to consider polymer microstructures and dynamics--issues critical to BRS. Using Raman spectroscopy, we demonstrate microstructural heterogeneities within polymeric scaffolds arising from integrated strain during fabrication and implantation...
February 26, 2018: Proceedings of the National Academy of Sciences of the United States of America
Liping Tong, Katsuhiko Saito, Qixin Guo, Han Zhou, Xingmei Guo, Tongxiang Fan, Di Zhang
A correlation function between the Raman intensities and the nearest-neighbor mean-square relative displacement (MSRD) [Formula: see text] of local Bi-O bonds is successfully established based on x-ray absorption fine structure (XAFS) and temperature-dependent Raman spectra in the temperature range 77-300 K in amorphous and crystalline Gd2.95 Yb0.02 Bi0.02 Er0.01 Ga5 O12 . The structural symmetries of Gd2.95 Yb0.02 Bi0.02 Er0.01 Ga5 O12 are described by using [Formula: see text] of local Bi-O bonds. More importantly, Gd2...
February 23, 2018: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Maryam Sardar, Chen Jun, Zaka Ullah, Aasma Tabassum, Mohsan Jelani, Ju Cheng, Yuxiang Sun, Xueming Lv, Lu Jian
We irradiate the single crystal boron-doped silicon (Si) at various laser fluences with 100 laser shots in ambient air at room temperature using an Nd:YAG laser and investigate its surface morphology and optical properties. The optical microscopy gives evidence of the formation of a crater and reveals that the heat-affected zone and melted area are increased with increase in laser fluence from 1.1 to 15.4  J/cm2 . The micrographs obtained by scanning electron microscopy (SEM) show that the micro- and nano-structures such as microcracks, bubbles, nucleation sites, clusters, redeposited layered material, nanoparticles, and alike water droplet structures are formed on a laser-exposed Si surface...
February 20, 2018: Applied Optics
Idio Alves de Sousa Filho, Tatiane Martins Lobo, Cesar Koppe Grisolia, Ingrid Távora Weber, Marly Eiko Osugi
Etoposide is an antineoplastic agent used for treating lung cancer, testicular cancer, breast cancer, pediatric cancers, and lymphomas. It is a pollutant due to its mutagenic and carcinogenic potential. Disposal of waste from this drug is still insufficiently safe, and there is no appropriate waste treatment. Therefore, it is important to use advanced oxidative processes (AOPs) for the treatment and disposal of medicines like this. The use of strontium stannate (SrSnO3 ) as a catalyst in heterogeneous photocatalysis reactions has emerged as an alternative for the removal of organic pollutants...
February 20, 2018: Environmental Science and Pollution Research International
Vemula Mohana Krishna, T Somanathan, E Manikandan, Kiran Kumar Tadi, S Uvarajan
Carbon nanotubes (CNTs) are still receiving much attention in bio-sensing applications due to their remarkable properties. In this present research work, fibre-like carbon nanotubes (f-CNTs) were successfully fabricated over copper-molybdenum (Cu-Mo) substituted alumina nanoparticles at atmospheric pressure by chemical vapor deposition (CVD) technique and effectively employed as a neurotransmitter dopamine (DA) sensor. The obtained product was purified and structurally characterized by various techniques such as, field emission scanning electron microscope (FESEM), energy dispersive X-ray spectroscopy (EDX), Raman spectroscopy, high resolution transmission electron microscope (HRTEM) and X-ray photoelectron spectroscopy (XPS) analysis...
August 1, 2018: Journal of Nanoscience and Nanotechnology
Katarzyna Siwińska-Stefańska, Monika Fluder, Włodzimierz Tylus, Teofil Jesionowski
A novel type of photocatalyst - hybrids of amino-grafted titania and reduced graphene oxide - was synthesized by a hydrothermal method. The hybrids were comprehensively analyzed, including determination of their morphology (TEM), porous structure parameters (low-temperature N2 sorption) and crystalline structure (XRD). Additionally, to confirm the effective bonding of the amino-grafted titania and reduced graphene oxide, Raman and X-ray photoelectron spectroscopy (XPS) were used, in addition to elemental analysis...
February 15, 2018: Journal of Environmental Management
Gajendra Kumar Inwati, Yashvant Rao, Man Singh
The Cu nanoparticles (Cu NPs) were grown in soda-lime glass matrix through Cu + ↔ Na + ion exchange methods under thermal annealing in an open environment and studied variation in their size on tunable plasmonic behaviour, optical absorption spectra and photoluminescence (PL). A blue shift from 570 to 560 nm was observed in localized surface plasmon resonance (SPR) of Cu NPs from 550 to 650 °C. A mutual relation between size and surface plasmon resonance with full width half maxima (FWHM) has been derived for plasmonic properties at variable temperatures...
February 14, 2018: Scientific Reports
Krishnamoorthy Rajavel, Padmanapan Saravanan, Ramasamy Thangavelu Rajendra Kumar
An investigation on varying experimental parameters such as solution quantity (2.5, 5 and 7.5 mL) and reaction time (15, 30, 45 and 60 min) was carried out for the production of high-quality multiwalled carbon nanotubes (MWCNTs) in one step pyrolysis. Structural analysis revealed the uniform diameter distribution and the length of nanotubes in the range of 60-80 nm and 0.4-2 μm, respectively. Raman and X-ray diffraction analysis showed a remarkable reduction in defect density with increase in graphitization degree, upon increasing the solution volume and reaction time...
May 1, 2018: Journal of Nanoscience and Nanotechnology
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