نتایج جستجو برای: raman spectra

تعداد نتایج: 138355  

Journal: :Optics letters 2009
Thomas Seeger Johannes Kiefer Alfred Leipertz Brian D Patterson Christopher J Kliewer Thomas B Settersten

Time-resolved pure-rotational coherent anti-Stokes Raman spectroscopy using picosecond-duration laser pulses is investigated for gas thermometry. The use of picosecond laser pulses significantly reduces background caused by scattering of the probe beam, and delayed probing of the Raman coherence enables elimination of interference from nonresonant four-wave mixing processes. Temperatures inferr...

2006
Sergio Godoy Penteado Claudio S. Meneses Anderson de Oliveira Lobo Airton Abrahao Martin Herculano da Silva Martinho

The biochemical changes on normal and degenerated tissues of rotator cuff supraspinatus tendons were probed by FT-Raman spectroscopy. The Raman spectra showed differences on the spectral regions of cysteine, amino acids, nucleic acids, carbohydrates, and lipids. These spectral differences were assigned to pathological biochemical alterations due to the degenerative process of the tendon. Princi...

Journal: :Optics letters 2001
I V Ermakov M R Ermakova R W McClane W Gellermann

We have used resonance Raman scattering as a novel noninvasive optical technology to measure carotenoid antioxidants in living human tissues of healthy volunteers. By use of blue-green laser excitation, clearly distinguishable carotenoid Raman spectra superimposed on a fluorescence background are obtained. The Raman spectra are obtained within less than a minute, and the required laser light ex...

Journal: :Journal of biomedical optics 2015
Young Ju Lee Hyung Joon Ahn Gi-Ja Lee Gyeong Bok Jung Gihyun Lee Dohyun Kim Jae-Ho Shin Kyung-Hyun Jin Hun-Kuk Park

The study was to investigate the changes in biochemical properties of activated mature CD8+ T cells related to apoptosis at a molecular level. We confirmed the activation and apoptosis of CD8+ T cells by fluorescence-activated cell sorting and atomic force microscopy and then performed Raman spectral measurements on activated mature CD8+ T cells and cellular deoxyribose nucleic acid (DNA). In t...

2016
Taro Ichimura Liang-da Chiu Katsumasa Fujita Hiroaki Machiyama Tomoyuki Yamaguchi Tomonobu M. Watanabe Hideaki Fujita

The acquired immune system, mainly composed of T and B lymphocytes, plays a key role in protecting the host from infection. It is important and technically challenging to identify cell types and their activation status in living and intact immune cells, without staining or killing the cells. Using Raman spectroscopy, we succeeded in discriminating between living T cells and B cells, and visuali...

Journal: :The journal of physical chemistry. B 2005
Adam D McFarland Matthew A Young Jon A Dieringer Richard P Van Duyne

A detailed wavelength-scanned surface-enhanced Raman excitation spectroscopy (WS SERES) study of benzenethiol adsorbed on Ag nanoparticle arrays, fabricated by nanosphere lithography (NSL), is presented. These NSL-derived Ag nanoparticle array surfaces are both structurally well-characterized and extremely uniform in size. The WS SERES spectra are correlated, both spatially and spectrally, with...

2003
S. Piscanec A. C. Ferrari M. Cantoro S. Hofmann J. A. Zapien Y. Lifshitz S. T. Lee J. Robertson

We measure the effects of phonon confinement on the Raman spectra of silicon nanowires (SiNWs). We show how previous reports of phonon confinement in SiNWs and nanostructures are actually inconsistent with phonon confinement, but are due to the intense local heating caused by the laser power used for Raman measurements. This is peculiar to nanostructures, and would require orders of magnitude h...

Journal: :Optics letters 2008
Michael A Short Stephen Lam Annette McWilliams Jianhua Zhao Harvey Lui Haishan Zeng

A near-infrared Raman system was developed to collect real-time in vivo human lung spectra. The excitation light and the emission were guided to and from the tissue surface by a reusable fiber catheter passed down the instrument channel of a bronchoscope. Two-stage filtering was used to reduce laser noise, fluorescence, and Raman emissions from the fibers. A second fiber bundle guided the emiss...

The complexes [MoS (CUNCS) ] w hen x = 2,3,4 and [MoOS , (CUNCS) ] when y = 2, 3 have been prepared by the reaction of CuSCN with [P(C H ) ] [MoS ] or [P(C H ) ] [MOOS ] in dry degassed acetone or DMFsolution and recrystallized from dichloromethane, the attempted preparation of [MoS (AgSCN) ] and [MOOS (AgSCN) ] failed. The Raman, IR, UV/VIS, C-nmr and Mo-nmr spectra of the co...

Journal: :Photochemistry and photobiology 1998
A Mahadevan-Jansen M F Mitchell N Ramanujam A Malpica S Thomsen U Utzinger R Richards-Kortum

In this study, we investigate the potential of near-infrared Raman spectroscopy to differentiate cervical precancers from normal tissues, inflammation and metaplasia and to differentially diagnose low-grade and high-grade precancers. Near infrared Raman spectra were measured from 36 biopsies from 18 patients in vitro. Detection algorithms were developed and evaluated relative to histopathologic...

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