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Raman crystallinity

Rebecca A Halliwell, Rajni M Bhardwaj, Cameron Brown, Naomi E B Briggs, Jaclyn Dunn, John Robertson, Alison Nordon, Alastair J Florence
Carbamazepine is an active pharmaceutical ingredient used in the treatment of epilepsy that can form at least five polymorphic forms. Metastable form IV was originally discovered from crystallisation with polymer additives however has not been observed from subsequent solvent only crystallisation efforts. This work reports the reproducible formation of phase pure crystalline form IV by spray drying of methanolic carbamazepine solution. Characterisation of the material was carried out using diffraction, SEM and DSC...
April 18, 2017: Journal of Pharmaceutical Sciences
Yuan-Ting Lin, Paritosh Vilas Wadekar, Hsiang-Shun Kao, Yu-Jung Zheng, Quark Yung-Sung Chen, Hui-Chun Huang, Cheng-Maw Cheng, New-Jin Ho, Li-Wei Tu
In this report, ferromagnetic interactions in modulation-doped GaMnN nanorods grown on Si (111) substrate by plasma-assisted molecular beam epitaxy are investigated with the prospect of achieving a room temperature ferromagnetic semiconductor. Our results indicate the thickness of GaN layer in each GaN/MnN pair, as well as Mn-doping levels, are essential for suppressing secondary phases as well as enhancing the magnetic moment. For these optimized samples, structural analysis by high-resolution X-ray diffractometry and Raman spectroscopy verifies single-crystalline modulation-doped GaMnN nanorods with Ga sites substituted by Mn atoms...
December 2017: Nanoscale Research Letters
Kwangsik Jeong, Seungjong Park, Dambi Park, Min Ahn, Jeonghwa Han, Wonjun Yang, Hong-Sik Jeong, Mann-Ho Cho
We investigated changes in the crystal structure of GeTe during its phase transition. Using density functional theory (DFT) calculations, four possible crystal structures were identified: R3m, P1, Cm, and Fm3m. Among these, P1 and Cm were examined here for the first time. By calculating the internal energy of the crystal volume change, we verified that P1, R3m, and Cm can coexist in crystalline GeTe. The X-ray diffraction spectra of annealed and laser-irradiated GeTe films revealed coexisting P1 or R3m and Cm...
April 19, 2017: Scientific Reports
Zongnan Zhang, Haijiao Zhang
Porous nanomaterials have attracted extensive interests in adsorption, catalysis, biosensors, and biomedicine due to their high surface area, well-defined pore structure and tunable pore size. However, how to obtain porous nanomaterials of desirable component and unique structure with multifunctionalities and synergetic properties is still a great challenge. In this work, a novel nest-like Ag@mTiO2 hierarchical nanostructure with Ag nanoparticle as the core and a mesoporous crystalline TiO2 as the protective shell was successfully prepared by layer-by-layer assembly technique and alkali-etching hydrothermal route...
June 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
Kalyan Ghosh, Chee Yoon Yue, Md Moniruzzaman Sk, Rajeeb Kumar Jena
We have fabricated high energy density all-solid-state flexible asymmetric supercapacitor by using a facile novel 3-D hollow urchin shaped coaxial manganese dioxide@polyaniline (MnO2@PANI) composite as positive electrode and 3-D graphene foam (GF) as negative electrode materials with PVA/KOH gel electrolyte. The coaxial MnO2@PANI composite was fabricated by hydrothermal route followed by oxidation without use of an external oxidant. The formation mechanism of the 3-D hollow MnO2@PANI composite occurs first by nucleation and growth of the MnO2 crystal species via a dissolution-recrystallization and oriented attachment mechanisms, and then followed by oxidation of aniline monomers on the MnO2 crystalline template...
April 17, 2017: ACS Applied Materials & Interfaces
E Muchuweni, T S Sathiaraj, H Nyakotyo
Micro-ring structured zinc oxide (ZnO) thin films were prepared on glass substrates by spray pyrolysis and their structural, morphological, optical and electrical properties were investigated. X-ray Diffraction (XRD) analysis revealed the films' hexagonal wurtzite phase with a preferred (002) grain orientation. The mean crystallite size calculated on the basis of the Debye-Scherrer model was 24 nm and a small dislocation density of [Formula: see text] was obtained, indicating the existence of few lattice defects and good crystallinity...
April 2017: Heliyon
Camila Bezerra Melo Figueirêdo, Daniela Nadvorny, Amanda Carla Quintas de Medeiros Vieira, José Lamartine Soares Sobrinho, Pedro José Rolim Neto, Ping I Lee, Monica Felts de La Roca Soares
Benznidazole (BNZ), the only commercialized antichagasic drug, and the antifungal compound posaconazole (PCZ) have shown synergistic action in the therapy of Chagas disease, however both active pharmaceutical ingredients (APIs) exhibit low aqueous solubility potentially limiting their bioavailability and therapeutic efficacy. In this paper, we report for the first time the formation of a eutectic mixture as well as an amorphous solid solution of PCZ and BNZ (at the same characteristic ratio of 80:20wt%), which provided enhanced solubility and dissolution rate for both APIs...
April 12, 2017: International Journal of Pharmaceutics
Jinrong Wang, Huaping Zhu, Sha Li, Shujun Wang, Shuo Wang, Les Copeland
The effect of high pressure (HP) treatment at 200-600MPa for 30min on properties of three starches with different polymorphs was investigated. HP treatment altered greatly the morphology of wheat starch, especially at 400MPa or higher. The crystallinity of wheat starch decreased from 22.6% for native starch to 3.4% for starch after treatment at 600MPa. The short-range molecular order as measured by FTIR and Raman spectroscopy decreased with increasing treatment pressure. HP treatment had little effect on structural properties of potato and yam starches, except for yam starch after treatment at 600MPa...
April 13, 2017: International Journal of Biological Macromolecules
Chih-Hsien Wang, Chia-Chi Huang, Wenlung Chen
Methods to obtain pure proteins in large amounts are indispensible in protein research. We report here a large-scale/simultaneous isolation of taxon-specific crystallins (ɛ- and δ-crystallin) from the eye lenses of Mule duck. We also investigate the compositions, enzymatic activities, and structures of these purified taxon-specific proteins. A relatively mild method of ion-exchange chromatography was developed to fractionate ɛ-crystallin and δ-crystallin in large amount, ca. ∼6.60mg/g-lens and ∼41.0mg/g-lens, respectively...
April 6, 2017: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
George P Zograf, Mihail I Petrov, Dmitry A Zuev, Pavel A Dmitriev, Valentin A Milichko, Sergey V Makarov, Pavel A Belov
We propose a novel photothermal approach based on resonant dielectric nanoparticles, which possess imaginary part of permittivity significantly smaller as compared to metal ones. We show both experimentally and theoretically that a spherical silicon nanoparticle with a magnetic quadrupolar Mie resonance converts light to heat up to 4 times more effectively than similar spherical gold nanoparticle at the same heating conditions. We observe photoinduced temperature raise up to 900 K with the silicon nanoparticle on a glass substrate at moderate intensities (<2 mW/μm(2)) and typical laser wavelength (633 nm)...
April 24, 2017: Nano Letters
Maria Anastasopoulou, Konstantinos C Vasilopoulos, Dimitrios F Anagnostopoulos, Ioannis Koutselas, Demetrios K Papayannis, Michael A Karakassides
Strontium borophosphate glasses of composition xSrO•(1-x)•[0.68B2O3•0.32P2O5], 0.40 ≤ x ≤ 0.68, have been prepared by fast quenching of high temperature melts and studied using Raman spectroscopy. In order to comprehend and confirm the obtained spectroscopic Raman data, crystalline compounds and glass-ceramics of analogous compositions were also prepared and studied. Also, ab initio molecular electronic structure theory was used to predict and confirm the experimental vibrational spectra The comparison between theoretical and experimental results showed a good overall agreement...
April 11, 2017: Journal of Physical Chemistry. B
J Vinoth Kumar, R Karthik, Shen-Ming Chen, N Raja, V Selvam, V Muthuraj
The construction and characterization of selective and sensitive non-enzymatic hydrogen peroxide (H2O2) electrochemical sensor based on sphere-like zirconium molybdate (ZrMo2O8) nanostructure are reported for the first time. The sphere-like ZrMo2O8 were prepared via a simple hydrothermal route followed by annealing process. The structural and morphological properties were investigated by various analytical and spectroscopic techniques such as XRD, Raman, SEM, EDX, TEM, and XPS analysis. Furthermore, the electrochemical properties were investigated by cyclic voltammetry and amperometric techniques...
March 31, 2017: Journal of Colloid and Interface Science
Thamires A Lima, Vitor H Paschoal, Luiz F O Faria, Mauro C C Ribeiro
Differential scanning calorimetry, X-ray diffraction, and Raman spectroscopy were used to reveal the premelting events precursors of melting of the ionic liquid triethylsulfonium bis(trifluoromethanesufonyl)imide, [S222][NTf2]. On heating the crystalline phase of [S222][NTf2], melting occurs along a sequence of at least three steps. First, the crystalline long-range order breaks down, but local order is retained. The second step is characterized by conformational freedom of the ethyl chains of cations related to premelting of nonpolar domains, and the complete melting finally occurs when anions acquire conformational freedom...
April 19, 2017: Journal of Physical Chemistry. B
Eli Fahrenkrug, Jessica Rafson, Mitchell Lancaster, Stephen Maldonado
The direct preparation of crystalline indium antimonide (InSb) by the electrodeposition of antimony (Sb) onto indium (In) working electrodes has been demonstrated. When Sb is electrodeposited from dilute aqueous electrolytes containing dissolved Sb2O3, an alloying reaction is possible between Sb and In if any surface oxide films are first thoroughly removed from the electrode. The presented Raman spectra detail the interplay between the formation of crystalline InSb and the accumulation of Sb as either amorphous or crystalline aggregates on the electrode surface as a function of time, temperature, potential, and electrolyte composition...
April 7, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
J Łojewska, I Rabin, D Pawcenis, J Bagniuk, M A Aksamit-Koperska, M Sitarz, M Missori, M Krutzsch
Ancient papyri are a written heritage of culture that flourished more than 3000 years ago in Egypt. One of the most significant collections in the world is housed in the Egyptian Museum and Papyrus Collection in Berlin, from where the samples for our investigation come. The papyrologists, curators and conservators of such collections search intensely for the analytical detail that would allow ancient papyri to be distinguished from modern fabrications, in order to detect possible forgeries, assess papyrus deterioration state, and improve the design of storage conditions and conservation methods...
April 6, 2017: Scientific Reports
Smail Hamamda, Ahmed Jari, S Revo, K Ivanenko, Youcef Jari, T Avramenko
The aim of this research is the thermostructural study of Cu-Ti, Cu-Ti 1 vol% multiwall carbon nanotubes (MWCNTs) and Cu-Ti 3 vol% MWCNTs. Several investigation techniques were used to achieve this objective. Dilatometric data show that the coefficient of thermal expansion of the nanocomposite containing less multiwall carbon nanotubes is linear and small. The same nanocomposite exhibits regular heat transfer and weak mass exchange with the environment. Raman spectroscopy shows that the nanocomposite with more MWCNTs contains more defects...
December 2017: Nanoscale Research Letters
Seong Gi Jo, Bong Gi Kim, Jinsang Kim, JeongYong Kim, Jinsoo Joo
The waveguiding of surface enhanced Raman scattering (SERS) signals was demonstrated by using organic semiconducting microrods (MRs) hybridized with functionalized gold nanoparticles (Au-NPs). Organic semiconducting 1,4-bis(3,5-bis(trifluoromethyl) styryl)-2,5-dibromobenzene (TSDB) crystalline MRs were fabricated as active optical waveguiding system using a self-assembly method. The static SERS effect and the enhancement of photoluminescence were simultaneously observed for the TSDB MRs hybridized with Au-NPs...
March 20, 2017: Optics Express
Kamal Baba, Simon Bulou, Patrick Choquet, Nicolas D Boscher
Due to the undeniable industrial advantages of low-temperature atmospheric-pressure plasma processes, such as low cost, low temperature, easy implementation, and in-line process capabilities, they have become the most promising next-generation candidate system for replacing thermal chemical vapor deposition or wet chemical processes for the deposition of functional coatings. In the work detailed in this article, photocatalytic anatase TiO2 thin films were deposited at a low temperature on polymer optical fibers using an atmospheric-pressure plasma process...
April 6, 2017: ACS Applied Materials & Interfaces
Shine Tone, Masahiro Hasegawa, Giuseppe Pezzotti, Leonardo Puppulin, Akihiro Sudo
Although the introduction of highly cross-linked polyethylene is effective in reducing the amount of wear, there are still major concerns regarding the use of this material in total knee arthroplasty (TKA), essentially due to the reduction of fatigue resistance and toughness. Monitoring the in-vivo performance of different types of UHMWPE is a much needed task to tackle the lack of information on which should be the most reliable choice for TKA. The present study was aimed at investigating the mid-term degradation of electron beam sterilized conventional UHMWPE tibial plates...
March 27, 2017: Acta Biomaterialia
Ze Liu
Controlled fabrication of metallic nanostructures plays a central role in much of modern science and technology, because changing the dimensions of a nanocrystal enables tailoring of its mechanical, electronic, optical, catalytic and antibacterial properties. Here we show direct superplastic nanoimprinting (SPNI) of crystalline metals well below their melting temperatures, generating ordered nanowire arrays with aspect ratios up to ∼2,000 and imprinting features as small as 8 nm. Surface-enhanced Raman scattering (SERS) spectra reveal strongly enhanced electromagnetic signals from the prepared nanorod arrays with sizes up to ∼100 nm, which indicates that our technique can provide an ideal way to fabricate robust SERS substrates...
March 28, 2017: Nature Communications
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