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Horsnell J Stonelake P Christie-Brown J Shetty G Hutchings J Kendall C Stone N 《The Analyst》2010,135(12):3042-3047
Sentinel Lymph Node Biopsy has become the standard surgical procedure for the sampling of axillary lymph nodes in breast cancer. Intra operative node assessment is currently not offered to the majority of patients but would allow definitive axillary surgery to take place immediately. This would confer benefits both to the patient and to the healthcare system. Our experimental study aims to demonstrate that a Raman spectroscopy probe device could overcome many of the disadvantages of current intra-operative analysis techniques. 38 axillary lymph nodes, 25 negative and 13 positive from 20 patients undergoing breast surgery for invasive breast cancer were assessed using a commercially available Raman spectroscopy probe. Spectra were assessed using principal component fed linear discriminant analysis trained by the histopathology results. Leave one node out cross validation achieved a sensitivity of up to 92% and a specificity of up to 100% in differentiating between normal and metastatic lymph nodes. 相似文献
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Guo M Lu J Wu Y Wang Y Luo M 《Langmuir : the ACS journal of surfaces and colloids》2011,27(7):3872-3877
Surface properties of rare-earth (RE) doped ceria (RE = Sm, Gd, Pr, and Tb) were investigated by UV (325 nm) and visible (514, 633, and 785 nm) Raman spectroscopy, combined with UV-vis diffuse reflectance spectroscopy, high-resolution transmission electron microscopy, and X-ray photoelectron spectra techniques. It was found that the optical absorption property of samples, the wavelength of detecting laser line, and the inhomogeneous distribution of the dopants significantly affected the obtained surface information, namely, the peak intensity and shape at ca. 460 and 570 cm(-1), as well as the observed oxygen vacancy concentration (A(570)/A(460)). The UV laser line detected the surface information of RE-doped ceria and disclosed the presence of many oxygen vacancies in the samples. The visible laser lines penetrated into the inner layer of the Sm- or Gd-doped CeO(2) and reflected the whole information of samples because of their weak absorptions of the visible laser. However, the Pr- or Tb-doped CeO(2) absorbed visible light strongly; thus, the laser can only determine the outer surface information of the sample. 相似文献
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Polarized laser Raman studies of biological polymers 总被引:1,自引:0,他引:1
B Fanconi B Tomlinson L A Nafie W Small W L Peticolas 《The Journal of chemical physics》1969,51(9):3993-4005
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Deep UV resonance Raman micro-spectroscopy (lambda(exc) = 244 nm) was applied for a highly sensitive, selective, and gentle localization of the antimalarial quinine in situ in cinchona bark. The high potential of the method was demonstrated by the detection of small amounts of the alkaloid in the plant material without any further sample preparation, where conventional (non-resonant) Raman microscopy was unsuccessful due to a strong fluorescence background. The resonance Raman spectrum of cinchona bark corresponds well with that of quinine; it can be distinguished from its diastereomer quinidine via the mode at 831 cm(-1), which is shifted to 843 cm(-1) in the case of quinidine. This vibration involves a bending motion within the side chain around the chiral center of quinine. Vibrations belonging to the quinoline ring (important for its antimalarial activity in forming pi-pi-interactions to hemozoin) and the vinyl group are resonantly enhanced in the UV Raman spectra. A convincing mode assignment is derived by means of a combination of NIR Raman spectroscopy and DFT calculations. The Raman spectra of quinine in cinchona bark are modeled by considering a hydrous environment that causes a shift of the band at 1362 compared with 1371 cm(-1) in anhydrous quinine. This intense vibration is therefore sensitive to the presence of an aqueous environment and is assigned mostly to a stretching motion within the quinoline ring. The presented results nicely show the sensitivity of Raman spectroscopy to monitor subtle differences within the molecular structure and the influence of a biological relevant hydrous environment and trace low concentrated pharmaceutical relevant active agents in plant material. 相似文献
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Zhenning Gu Feng Liang Zheyi Chen Anil Sadana Carter Kittrell W.E. Billups Robert H. Hauge Richard E. Smalley 《Chemical physics letters》2005,410(4-6):467-470
The charge transfer induced lithiation of single-wall carbon nanotubes (SWNTs) was investigated by in situ monitoring by Raman spectroscopy as lithium was added incrementally to a dispersion of SWNTs in liquid ammonia. Charge transfer from liquid ammonia solvated lithium to the SWNTs led to intercalation of lithium into the SWNT ropes, as well as to the semi-covalent lithiation of the SWNTs. Raman spectra of the SWNTs recorded as lithium was added showed a 30 wavenumber downshift of the G band (1594 cm−1) with the concomitant appearance of a new peak at 1350 cm−1 that was assigned as the signature of the lithiated SWNTs. Addition of 1-iodododecane to the lithiated SWNTs resulted in the covalent attachment of dodecyl groups. The intercalation of lithium throughout the SWNT ropes led to complete dodecylation of all individual SWNTs. 相似文献
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《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1990,46(2):253-275
The paper aims to demonstrate the new-found versatility that FT Raman methods provide to those who work on bio compounds. Almost all solid specimens give spectra easily, rapidly and non-destructively. The point is made that since results are now available on impure raw materials or partially purified extracts, the body of classical Raman data in the literature derived from purified materials can now be exploited. New spectra on foodstuffs, carbohydrates and lactones are offered and some progress on detailed structural/spectroscopic analysis is included to demonstrate the significance of the development. 相似文献
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The detection of thiols on extraterrestrial bodies could provide evidence for life, as well as a host of potential prebiological or abiological processes. Here, we report a novel protocol to analyze organic thiols by microchip CE with LIF detection. Thiols were labeled with Pacific Blue C5 maleimide and analyzed by MEKC. The separation buffer consisted of 15 mM tetraborate pH 9.2 and 25 mM SDS. The optimized method provided LODs ranging from 1.4 to 15 nM. The method was validated using samples collected from geothermal pools at Hot Creek Gorge, California, which were found to contain 2‐propanethiol and 1‐butanethiol in the nanomolar concentration range. These samples serve as chemical analogues to material potentially present in the reducing environment of primitive Earth and also at sulfurous regions of Mars. Hence, the protocol developed here enables highly sensitive thiol analysis in samples with complexity comparable to that expected in astrobiologically relevant extraterrestrial settings. This new protocol could be readily added to the existing suite of microfluidic chemical analyses developed for in situ planetary exploration; all that is required is the incorporation of two new reagents to the payload of an existing instrument concept. 相似文献
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Luteolin is one of the most common flavonoids, but its ability to complex metal ions (e.g. aluminum) is still being discussed. This work presents the results of structural investigation of the luteolin–Al(III) complexes in methanol:water solutions and in the solid state. The analysis was carried out using UV–vis and FT-Raman spectroscopy accompanied by Factor Analysis, deconvolution and quantum-chemical calculations. It was found that in acidic solutions two complexes of luteolin–Al(III) of 1:1 and 1:2 ligand:metal ratio are formed, where luteolin is one- and twofold deprotonated, respectively. Additionally, a third complex precipitated from a basic solution of 1:2 stoichiometry with a threefold deprotonated ligand was obtained. 相似文献
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Understanding interactions between Nafion (perfluorosulfonic acid) and Pt catalysts is important for the development and deployment of proton exchange membrane fuel cells. However, study of such interactions is challenging and Nafion/Pt interfacial structure remains elusive. In this study, adsorption of Nafion ionomer on Au and Pt surfaces was investigated for the first time by in situ surface-enhanced Raman spectroscopy. The study is made possible by the use of uniform SiO(2)@Au core-shell particle arrays which provides very strong enhancement of Raman scattering. The high surface sensitivity offered by this approach yields insightful information on interfacial Nafion structure. Through spectral comparison of several model compounds, vibration assignments of SERS bands were made. The SER spectra suggest the direct interaction of sulfonate group with the metal surfaces, in accord with cyclic voltammetric results. Comparison of present SERS results with previous IR spectra was briefly made. 相似文献
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Willis PA Greer F Lee MC Smith JA White VE Grunthaner FJ Sprague JJ Rolland JP 《Lab on a chip》2008,8(7):1024-1026
Photolithographically defined monolithic membrane valves utilizing Fluorocur perfluoropolyether (PFPE) were fabricated and characterized to be essentially unaltered after one million actuations and exposure to the environmental stresses associated with in situ exploration of Mars. 相似文献
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Raman mapping and in situ SERS spectroelectrochemical studies of 6-mercaptopurine SAMs on the gold electrode 总被引:1,自引:0,他引:1
Yang H Liu Y Liu Z Yang Y Jiang J Zhang Z Shen G Yu R 《The journal of physical chemistry. B》2005,109(7):2739-2744
The self-assembled monolayers (SAMs) of 6-mercaptopurine (6MP) were formed at the roughened polycrystalline gold surfaces in acid and alkaline media. The time-dependent Raman mapping spectral analysis in conjunction with the quantum calculations for the vibrational modes using ab initio BLYP/6-31G method suggested that both of the resulted 6MP SAMs adopted the same adsorption mode through the S atom of pyrimidine moiety and the N7 atom of the imidazole moiety anchoring the gold surface in a vertical way. The in situ surface-enhanced Raman scattering spectroelectrochemical experiment was conducted to examine the stability of the SAMs at various bias potentials. It was found that the detaching process of the 6MP SAMs from the surface involved one electron reduction as the voltage was applied at ca. 0.7 V vs a standard calomel electrode. 相似文献
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Xu L Kuang H Xu C Ma W Wang L Kotov NA 《Journal of the American Chemical Society》2012,134(3):1699-1709
Multiple properties of plasmonic assemblies are determined by their geometrical organization. While high degree of complexity was achieved for plasmonic superstructures based on nanoparticles (NPs), little is known about the stable and structurally reproducible plasmonic assemblies made up from geometrically diverse plasmonic building blocks. Among other possibilities, they open the door for the preparation of regiospecific isomers of nanoscale assemblies significant both from a fundamental point of view and optical applications. Here, we present a synthetic method for complex assemblies from NPs and nanorods (NRs) based on selective modification of NRs with DNA oligomers. Three types of assemblies denoted as End, Side, and Satellite isomers that display distinct elements of regiospecificity were prepared with the yield exceeding 85%. Multiple experimental methods independently verify various structural features, uniformity, and stability of the prepared assemblies. The presence of interparticle gaps with finely controlled geometrical parameters and inherently small size comparable with those of cellular organelles fomented their study as intracellular probes. Against initial expectations, SERS intensity for End, Side, and Satellite isomers was found to be dependent primarily on the number of the NPs in the superstructures rationalized with the help of electrical field simulations. Incubation of the label-free NP-NR assemblies with HeLa cells indicated sufficient field enhancement to detect structural lipids of mitochondria and potentially small metabolites. This provided the first proof-of-concept data for the possibility of real-time probing of the local organelle environment in live cells. Further studies should include structural optimization of the assemblies for multitarget monitoring of metabolic activity and further increase in complexity for applications in transformative optics. 相似文献
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B. Hathi P. M. Daniell M. Banaszkiewicz A. Hagermann M. R. Leese J. C. Zarnecki 《Journal of Thermal Analysis and Calorimetry》2007,87(2):585-590
This paper outlines the method of measurement
and analysis of the thermal conductivity instrument (THP) that has successfully
returned measurements from the atmosphere of Saturn’s moon Titan during
the descent of the Huygens probe on 14th January
2005.
The technique is validated by analysing laboratory calibration
data gathered by our instrument in three pure gases (nitrogen, methane, and
ethane) over Titan’s temperature range (90 to 180 K). Calibration results
show errors <1% compared to reference values when processed using this
method. 相似文献
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Takeuchi H 《Analytical sciences》2011,27(11):1077-1086
UV Raman spectroscopy is a powerful tool for investigating the structures and interactions of the aromatic side chains of Phe, Tyr, Trp, and His in proteins. This is because Raman bands of aromatic ring vibrations are selectively enhanced with UV excitation, and intensities and wavenumbers of Raman bands sensitively reflect structures and interactions. Interpretation of protein Raman spectra is greatly assisted by using empirical correlations between spectra and structure. Many Raman bands of aromatic side chains have been proposed to be useful as markers of structures and interactions on the basis of empirical correlations. This article reviews the usefulness and limitations of the Raman markers for protonation/deprotonation, conformation, metal coordination, environmental polarity, hydrogen bonding, hydrophobic interaction, and cation-π interaction of the aromatic side chains. The utility of Raman markers is demonstrated through an application to the structural analysis of a membrane-bound proton channel protein. 相似文献
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Luana R. Michels Flvia N.S. Fachel Juliana H. Azambuja Nicolly E. Gelsleichter Elizandra Braganhol Helder F. Teixeira 《Biomedical chromatography : BMC》2019,33(10)
A high‐performance liquid chromatography method for temozolomide (TMZ) determination in complex biological matrices was developed and validated for application in in vitro, ex vivo and in vivo studies of new nanotechnology‐based systems for TMZ nasal delivery. The method was able to quantify TMZ in nanoemulsions, following cellular uptake, in the porcine nasal mucosa and in mouse plasma and brain. Analyses were performed on a C18 column at 35°C, under UV detection at 330 nm. The mobile phase was methanol–acetic acid 0.5% (30:70, v/v), eluted at an isocratic flow rate of 1.1 mL/min. The method was found to be specific, precise, accurate, robust and linear (0.05 to 5 μg/mL) for TMZ determination in all matrices. No interference of TMZ degradation products was found under various stress conditions such as acidic, alkaline, oxidative, light and thermal exposure, demonstrating stability. The method was applied for the quantification of TMZ in different matrices, i.e. the efficiency of nanoemulsions in vitro in increasing TMZ cellular uptake, ex vivo TMZ permeation and retention in the porcine nasal mucosa tissue, and for in vivo TMZ quantification in mouse brain following intranasal nanoemulsion administration compared with free TMZ. 相似文献
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Summary An ATR technique is presented for UV/VIS analytical measurements featuring a solid glass ATR probe which is connected to a fast diode array spectrometer via optical fibers. It is demonstrated that samples with very high absorption, which are of some practical interest in process and quality control in chemistry and pharmacy, can be directly investigated with an overall reproducibility of 0.1% in concentration.
ATR-Methode für UV/VIS-analytische Messungen相似文献
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M. Bouabdallaoui Z. Aouzal S. Ben Jadi A. El Jaouhari M. Bazzaoui G. Lévi J. Aubard E. A. Bazzaoui 《Journal of Solid State Electrochemistry》2017,21(12):3519-3532
Polythiophene films have been electrochemically synthesized on platinum electrodes by anodic oxidation of thiophene in CH3CN-LiClO4 organic solution, then galvanostatically polarized in the same but monomer-free electrolytic medium to obtain the reduced, oxidized, and overoxidized states of the polymer. X-ray photoelectron spectroscopy (XPS) measurements were performed to investigate the changes within the chemical composition accompanying the overoxidation of the polythiophene (PT) film and connected to degradation mechanisms reported in the literature. Ex situ resonance Raman spectroscopy (RRS) studies of the three oxidation states, with red and near-infrared excitation laser lines, lead to complementary insights about the degradation process of this polymer. Particularly, marked modifications of the positions, widths, and relative intensities of the Raman bands are attributed to structural transformations and the appearance of defects in the polymer chains. Moreover, in situ RRS experiments, during the gradual transition between the reduced and overoxidized states, allow to determine the electrochemical stability threshold of the PT. In the reversibility domain, the quinoid to aromatic intensity ratio of the ring C=C symmetric stretching obeys a Nernst-like equation when the applied potential to the PT/Pt working electrode is varied. 相似文献