We report a mechanistic analysis of photodamage in coherent anti-Stokes Raman scattering (CARS) microscopy. Photodamage to the myelin sheath in spinal tissues is induced by using the point scan mode and is featured by myelin splitting and shockwaves with broadband emission. Our measurement of photodamage rate versus the excitation power reveals that both linear and nonlinear mechanisms are involved. Moreover, we show that vibrational absorption induced by coherent Raman processes significantly contributes to the nonlinear damage at high peak powers. For CARS imaging of cultured cells, the photodamage is characterized by plasma membrane blebbing and is dominated by a second order mechanism. Our study suggests that for dense samples such as the myelin sheath, CARS imaging induced photodamage can be minimized by using laser beams with relatively long near IR wavelengths and a repetition rate of a few MHz. For less dense samples such as cultured cells, laser pulses of higher repetition rates are ...
Coherent Anti-Stokes Raman Scattering (CARS)-microscopy has in recent years developed as a promising microscopical technique for label-free microscopy of living cells. We propose a new concept, spectral focusing, for highly efficient coherent anti-Stokes Raman scattering (CARS) microscopy. It allows optimal use of the excitation energy of femtosecond laser pulses in terms of generated CARS signal against a low background. This is accomplished by introducing a linear chirp in the excitation pulses. The temporal delaying of the excitation pulses can be used to record vibrational spectra of a sample. Despite the inherently broad spectral width of the excitation pulses, the technique enables resolution of spectral features 60 times narrower than the bandwidth of the probe light. First applications of this technique are exemplified with CARS of micron sized crystallites of sodium nitroprusside, a commonly used hypotensive agent ...
The rather thin outermost layer of the mammalian skin, stratum corneum (SC), is a complex biomembrane which separates the water rich inside of the body from the dry outside. The skin surface can be exposed to rather extreme variations in ambient conditions (e.g. water activity, temperature and pH), with potential effects on the barrier function. Increased understanding of how the barrier is affected by such changes is highly relevant for regulation of transdermal uptake of exogenous chemicals. In the present study we investigate the effect of hydration and the use of a well-known humectant, urea, on skin barrier ultrastructure by means of confocal Raman microspectroscopy. We also perform dynamic vapor sorption (DVS) microbalance measurements to examine the water uptake capacity of SC pretreated with urea. Based on novel Raman images, constructed from 20 spectral maps, we can distinguish large water inclusions within the skin membrane exceeding the size of fully hydrated corneocytes. We show that ...
TY - JOUR. T1 - Resonance Raman and surface-enhanced resonance Raman studies of polymer-modified electrodes which mimic heme enzymes. AU - Bell, Steven. AU - Devenney, M.D.. AU - Grimshaw, J.. AU - Hara, S.. AU - Rice, J.H.. AU - Trocha-Grimshaw, J.. PY - 1998. Y1 - 1998. N2 - Iron-5,10,15,20-tetraphenylporphyrin (FeTPP) has been incorporated into films of a coordinating hydrogel polymer support medium, poly(gamma-ethyl-L-glutamate) (PEG) functionalised with imidazole pendant arms (PEG-Im), and studied in situ on silver electrodes using a combination of both resonance Raman (RR) and surface-enhanced resonance Raman (SERR) spectroscopy. The SERR spectra give information on the portion of the film close to the electrode surface while RR spectra probe the. AB - Iron-5,10,15,20-tetraphenylporphyrin (FeTPP) has been incorporated into films of a coordinating hydrogel polymer support medium, poly(gamma-ethyl-L-glutamate) (PEG) functionalised with imidazole pendant arms (PEG-Im), and studied in situ on ...
The clinical development of therapeutic peptides has been restricted to peptides for non-CNS diseases and parenteral dosage forms due to the poor permeation of peptides across the gastrointestinal mucosa and the blood-brain barrier. Quaternary ammonium palmitoyl glycol chitosan (GCPQ) nanoparticles facilitate the brain delivery of orally administered peptides such as leucine(5)-enkephalin, and here we examine the mechanism of GCPQ facilitated oral peptide absorption and brain delivery. By analyzing the oral biodistribution of radiolabeled GCPQ nanoparticles, the oral biodistribution of the model peptide leucine(5)-enkephalin and coherent anti-Stokes Raman scattering microscopy tissue images after an oral dose of deuterated GCPQ nanoparticles, we have established a number of facts. Although 85-90% of orally administered GCPQ nanoparticles are not absorbed from the gastrointestinal tract, a peak level of 2-3% of the oral GCPQ dose is detected in the blood 30 min after dosing, and these GCPQ ...
1. Wang P, Liu B, Zhang DL, Belew, MY, Tissenbaum HA, Cheng JX*. Imaging Lipid Metabolism in Live Caenorhabditis elegans Using Fingerprint Vibrations. Angewandte Chemie International Edition. 2014; 53:11787-11792 (In press; Impact factor: 13.7). 2. Wang P, Li JJ, Wang P, Hu CR, Zhang DL, Sturek, M, Cheng JX*. Label-free quantitative imaging of cholesterol in intact tissues by hyperspectral stimulated Raman scattering microscopy. Angewandte Chemie International Edition. 2013; 52:13042-6 (Impact factor: 13.7). 3. Zhang D#, Wang P#, Slipchenko MN, Ben-Amotz D, Weiner AM, Cheng JX*. Quantitative vibrational imaging by hyperspectral stimulated Raman scattering microscopy and multivariate curve resolution analysis. Analytical chemistry. 2013;85(1):98-106. # Equal contribution first author. (Impact factor: 5.8). 4. Liao CS#, Slipchenko MN#, Wang P#, Hu CR, Li JJ, Oglesbee RA, Cheng JX*. Microsecond Scale Vibrational Spectroscopic Imaging by Multiplex Stimulated Raman Scattering Microscopy. Light: ...
The ordinary Raman scattering (ORS) spectra of virion protein of Granulosis Virus of Cabbage Butterfly Preris rapae (PrGV-VP) and their surface-enhanced Raman scattering (SERS) spectra adsorbed on the surface of silver colloid particles have been found that the Raman signal in the SERS spectra was enhanced by a factor of about 8 X 102. In ORS spectra of PrGV-VP, it indicates that PrGV-VP has a predominantly random-coil secondary structures. All tyrosine residues are exposed. And the PrGV-VP has a gauche-gauche- gauche configuration of the C-C-S-S-C-C linkage. In SERS spectra of PrGV-VP, the intensities of bands related to COO group and NH2 group vibrations are relatively strong. We interpret that the PrGV-VP are adsorbed on the Ag surface through both the carboxylate groups and the amino groups. The efficient enhancement of amide I and amide II vibrations are impeded, because the peptide groups of PrGV-VP are screened by the side-chains amino acid residues. The Raman enhancement of PrGV-VP has a ...
This well established symposium will cover various aspects of modern Raman microscopy and detail the advantages of confocal Raman imaging and its applications. Scientific talks from distinguished speakers in academia and industry, the contributed talk and poster sessions, and the instrument demonstration will give the participants a deeper understanding of confocal Raman imaging.
The identification of normal and cancer breast tissue of rats was investigated using high-frequency (HF) FT-Raman spectroscopy with a near-infrared excitation source on in vivo and ex vivo measurements. Significant differences in the Raman intensities of prominent Raman bands of lipids and proteins structures (2,800-3,100 cm(-1)) as well as in the broad band of water (3,100-3,550 cm(-1)) were observed in mean normal and cancer tissue spectra. The multivariate statistical analysis methods of principal components analysis (PCA) and linear discriminant analysis (LDA) were performed on all high-frequency Raman spectra of normal and cancer tissues. LDA results with the leave-one-out cross-validation option yielded a discrimination accuracy of 77.2, 83.3, and 100% for in vivo transcutaneous, in vivo skin-removed, and ex vivo biopsy HF Raman spectra. Despite the lower discrimination value for the in vivo transcutaneous measurements, which could be explained by the breathing movement and skin ...
Confocal Raman microscopy is a high-resolution imaging technique that is widely used for the characterization of materials and specimens in terms of thei...
Stimulated Raman scattering (SRS) microscopy allows label-free chemical imaging based on vibrational spectroscopy. Narrowband excitation with picosecond lasers creates the highest signal levels and enables imaging speeds up to video-rate, but it sacrifices chemical specificity in samples with overlapping bands compared to broadband (multiplex) excitation. We develop a rapidly tunable picosecond optical parametric oscillator with an electro-optical tunable Lyot filter, and demonstrate multicolor SRS microscopy with synchronized line-by-line wavelength tuning to avoid spectral artifacts due to sample movement. We show sensitive imaging of three different kinds of polymer beads and live HeLa cells with moving intracellular lipid droplets.. © 2013 Optical Society of America. Full Article , PDF Article ...
We believe that these imaging modalities have many potential medical applications for corneal/ocular surface imaging when the technology is further developed. Chronic topical glaucoma therapy has been associated with corneal damage characterized by the loss of certain corneal cell types as well as invasion of inflammatory cells. 48,49 CARS/TPAF would allow us to observe the number and type of corneal epithelial cells, which could determine the progression of corneal surface disease to better aid physician treatment. CARS/TPAF also has application in the area of corneal surgery, since this technology could be used to observe cell number and metabolic state (NAD[P]H level) at the site of a healing wound. Furthermore, CARS/TPAF can image at the level of the corneal endothelium to monitor cell health before and after cataract surgery. A combined CARS/TPAF system has recently been used to show the differences in lipid structures between in healthy and psoriasis-affected human skin. 50 By the same ...
Synthesis of new proteins, a key step in the central dogma of molecular biology, has been a major biological process by which cells respond rapidly to environmental cues in both physiological and pathological conditions. However, the selective visualization of a newly synthesized proteome in living systems with subcellular resolution has proven to be rather challenging, despite the extensive efforts along the lines of fluorescence staining, autoradiography, and mass spectrometry. Herein, we report an imaging technique to visualize nascent proteins by harnessing the emerging stimulated Raman scattering (SRS) microscopy coupled with metabolic incorporation of deuterium-labeled amino acids. As a first demonstration, we imaged newly synthesized proteins in live mammalian cells with high spatial-temporal resolution without fixation or staining. Subcellular compartments with fast protein turnover in HeLa and HEK293T cells, and newly grown neurites in differentiating neuron-like N2A cells, are clearly ...
We present a microscopic theory of quantum-size effects in surface-enhanced Raman scattering (SERS) from molecules adsorbed on small metal nanoparticles. In noble-metal nanoparticles, the confining potential has different effect on s-band and d-band electrons. Namely, the spillout of delocalized sp-electrons beyond the classical nanoparticle boundary results in an incomplete embedding of s-electron distribution in the background of localized d-electrons whose density profile follows more closely the classical shape. We demonstrate that a reduction of d-electron screening in the surface layer leads to the enhancement of the surface plasmon local field acting on a molecule located in a close proximity to metal surface. Our numerical calculations of Raman enhancement factor, performed using time-dependent local density approximation, show additional enhancement of the Raman signal which becomes more pronounced for small nanoparticles due to the larger ratio of surface layer to overall nanoparticle size.
Resonance Raman spectra of polymer chains in the single crystals of the diacetylenes FBS (2,4-hexadiynylene-di-p-fluorobenzene sulfonate), TS/FBS [6-(p-toluenesulfonyloxy)-2,4-p-fluorobenzene sulfonate] and TS6 (2,4-hexadiynylene-di-p-toluene sulfonate) are described theoretically by means of a Franckâ€"Condon model, which considers a chain length dependence. The electronic transition energies and matrix elements are calculated by means of a linear-combination-of-atomic-orbitalsâ€"molecular-orbital method calculation in the Hückel approach. We are able to describe the Raman excitation profiles as well as the Raman band profiles for two Raman active modes, i.e., the C+C-, and the C 3/4 C-stretching vibrations of the polymer chains. The model also contains a description of a side group vibrational mode which is enhanced by Fermi resonance with the C=C-stretching vibration. Observed Raman excitation profiles can be well simulated by these calculations. An evaluation of the parameters shows ...
In addition, confocal measurements can improve the rejection of stray light and reduce fluorescence interference. Not all confocal Raman microscopy designs are the same. Traditional confocal Raman microscopes, shown schematically in Figure 1(b), utilize a pinhole aperture placed in front of the spectrograph entrance slit. The Raman light is focused onto the pinhole and the diverging beam after the pinhole is then refocused onto the entrance slit of the spectrograph. Different pinhole apertures can be used to control the degree of confocality, while the entrance slit is used to control the spectral resolution of the spectrometer. While this true confocal configuration provides independent control of spatial and spectral resolutions, it is very difficult to align and to maintain optimum performance. This is because the beam is focused twice through two very small apertures. In practice, independent control of the two apertures offers little value. Typical slit widths must be less than 100 um to ...
A Raman spectrometry apparatus that is capable of measuring and compensating for variabilities in the apparatus comprises a source of substantially monochromatic radiation, means for simultaneously interfacing the radiation with a sample and a reference material, means for simultaneously acquiring at more than one wavelength a convolved Raman spectrum of the sample and a convolved spectrum of the reference material, and means for determining the convolution function of the convolved spectra and applying the convolution function to adjust the convolved Raman spectrum of the sample to produce thereby the standard Raman spectrum of the sample. A method for obtaining the standard Raman spectrum of a sample comprises: (a) simultaneously irradiating the sample and a reference material with a substantially monochromatic radiation source; (b) simultaneously acquiring at more than one wavelength a convolved Raman spectrum of the sample and a convolved spectrum of the reference material; (c) choosing the standard
As a superb tool to visualize and study the spatial-temporal distribution of chemicals, Raman microscopy has made a big impact in many disciplines of science. While label-free imaging has been the prevailing strategy in Raman microscopy, recent development and applications of vibrational/Raman tags, particul Recent Review Articles
Elkordy, Amal, Forbes, Robert T and Barry, Brian W (2008) Study of protein conformational stability and integrity using calorimetry and FT-Raman spectroscopy correlated with enzymatic activity. European Journal of Pharmaceutical Sciences, 33 (2). pp. 177-190. ISSN 0928-0987 ...
A thermoelectrically cooled surface-enhanced Raman Spectroscopy (TEC-SERS) fiber optic probe for real-time and in-situ monitoring of volatile organic compounds in gas, liquid, and soil environments. The TEC-SERS probe comprises a sample chamber for receiving a gas sample and a fiber optic Raman probe. The sample chamber comprises an inlet having a semipermeable membrane for separating moisture from the gas sample, a SERS substrate mounted on a thermoelectric cooler, a mass flow device for providing airflow, and an output port. The fiber optic Raman probe is operably coupled to a transparent window in the sample chamber for directing an optical excitation signal to irradiate the SERS substrate and for receiving a SERS optical signal from analytes from the gas sample that are in contact with the SERS substrate.
In situ surface-enhanced Raman scattering studies of the nitrosyl adduct of hemin adsorbed roughened silver surfaces in aqueous electrolytes
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We have introduced an in-situ Raman monitoring technique to investigate the crystallization process inside protein drops. In addition to a conventional vapour-diffusion process, a novel procedure which actively stimulates the evaporation from a protein drop during crystallization was also evaluated, with lysozyme as a model protein. In contrast to the conventional vapour-diffusion condition, the evaporation-stimulated growth of crystals was initiated in a simple dehydration scheme and completed within a significantly shorter time. To gain an understanding of crystallization behaviours under the conditions with and without such evaporation stimulation, confocal Raman spectroscopy combined with linear regression analysis was used to monitor both lysozyme and HEPES buffer concentrations in real time. The confocal measurements having a high spatial resolution and good linear response revealed areas of local inhomogeneity in protein concentration when the crystallization started. The acquired ...
This paper reports the first vibrational Raman optical activity (ROA) spectrum of a glycoprotein. The sample, orosomucoid (α1-acid glycoprotein), shows ROA bands characteristic of a high β-sheet content together with new bands which could be specific for the carbohydrate and its association with the protein. Our results suggest that ROA spectra of intact glycoproteins may contain information about both protein and carbohydrate conformation and the mutual influence on each others stability and conformation. ...
The formation of Ni silicides has been successfully monitored by Raman spectroscopy. Ni silicides formed at different annealing temperatures using rapid thermal annealing were analyzed using Rutherford backscattering spectroscopy and X-ray diffraction. Raman spectroscopy was further used to examine these samples. The results showed that Raman spectroscopy could accurately identify the phases of Ni silicides formed at various temperatures. These findings were used to demonstrate the increased thermal stability of NiSi by the addition of Pt. This study demonstrates the applicability of Raman spectroscopy for monitoring the formation of NiSi, which was suggested to be the future silicide for deep submicrometer integrated circuit processing. Raman spectroscopy offers a unique tool for phase identification at localized areas and mapping characterization of Ni silicides with micrometer spatial resolution ...
Christian Knipfer,1,3,* Johanna Motz,1 Werner Adler,4 Kathrin Brunner,5 Medhaine Tesfay Gebrekidan,2,3 Robert Hankel,2,3 Abbas Agaimy,5 Stefan Will,2,3 Andreas Braeuer,2,3 Friedrich Wilhelm Neukam,1,3 and Florian Stelzle1,3 1Department of Oral and Maxillofacial Surgery, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Erlangen, Germany 2Lehrstuhl für Technische Thermodynamik, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Erlangen, Germany 3Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Erlangen, Germany 4Department of Medical Informatics, Biometry and Epidemiology, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Erlangen, Germany 5Department of Pathology, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Erlangen, Germany *Corresponding author: [email protected] ...
This study aims to compare the diagnostic performance of the two different endoscope-based fiber-optic Raman probe designs (i.e., bevelled and volume Raman probes) for real-time, in vivo detection of gastric dysplasia at endoscopy. To conduct the clinical comparison, a total of 1,050 in vivo tissue Raman spectra (normal: n = 864; dysplasia: n = 186) were acquired from 66 gastric patients (normal: n = 48; dysplasia: n = 18) by using bevelled Raman probe, while a total of 1,913 in vivo tissue Raman spectra (normal: n = 1,786; dysplasia: n = 127) were acquired from 98 gastric patients (normal: n = 87; dysplasia: n = 11) by using volume Raman probe. The bevelled Raman probe provides approximately twofold improvements in tissue Raman-to-autofluorescence intensity ratios as compared to the use of volume Raman probe. Partial least squares discriminant analysis together with leave-one patient-out cross-validation on in vivo tissue Raman spectra acquired yields a diagnostic accuracy of 93.0 % ...
Twenty-three common used Chinese medicinal raw materials were directly determined with Fourier Transform Raman spectroscppy for the first time. Varied chemical components of different medicinal materials lead to different characters in vibration frequency of Raman functional groups. It was found that the vibration frequency variance follows a certain specific regularity. This method is relatively more precise and quicker, and without damage of the sample.
The aim of this study is to investigate the morphological and chemical changes of demineralized dentin collagen-matrix and resin/dentin interface associated with chitosan/riboflavin modification. Dentin disc specimens were prepared from sound molars, acid-etched with 35% phosphoric acid and modified with either 0.1% riboflavin or chitosan/riboflavin (Ch/RF ratios 1:4 or 1:1) and photo-activated by UVA. Morphological and chemical changes associated with surface modification were characterized by SEM and micro-Raman spectroscopy. Dentin surfaces of sound molars were exposed, acid-etched, and modified as described before. Etch-and-rinse dentin adhesive was applied, light-cured, and layered with resin-restorative composite. The resin infiltration and resin/dentin interface were characterized by micro-Raman spectroscopy and SEM. An open-intact collagen network-structure, formation of uniform hybrid-layer and higher resin infiltration were found with 0.1%RF and Ch/RF 1:4 modifications. Raman analysis ...
In light microscopy an object is illuminated with a lamp or a laser and the transmitted, reflected or fluorescent light is detected to get information on the object. In the project two approaches will be developed to study small particles and their interaction with living cells: Light Sheet Fluorescence Microscopy and Complex Beam Scattering Microscopy. In standard fluorescence microscopy the entire sample is illuminated and there is an important background arising from fluorescent material that is out of focus. In this project we will illuminate the sample with a sheet of light that coincides with the focal plane of the microscope, so that only that part of the sample that is in focus is illuminated. This can be realized with an optical fiber or by illuminating through the microscope objective lens onto an inclined mirror mounted on the sample holder. These solutions should be inexpensive and compatible with existing microscopes. For the study of small sub-resolution features in a sample we ...
The formation of the basoapical polarity axis in epithelia is critical for maintaining the homeostasis of differentiated tissues. Factors that influence cancer development notoriously affect tissue organization. Apical polarity appears as a specific tissue feature that, once disrupted, would facilitate the onset of mammary tumors. Thus, developing means to rapidly measure apical polarity alterations would greatly favor screening for factors that endanger or protect the breast epithelium. A Raman scattering based platform was used for label-free determination of apical polarity in live breast epithelial structures (acini) produced in three-dimensional cell culture. The coherent anti-Stokes Raman scattering signal permitted the visualization of the apical and basal surfaces in the equatorial plane of an acinus. Raman microspectroscopy subsequently revealed that in polarized acini lipids were more ordered at the apical membranes compared to basal membranes, and that an inverse situation occurred in ...
Precision Raman Equipment for Confocal Raman Spectroscopy. Find out about our Raman Spectroscopy Equipment, including Confocal Raman Microscope.
Journal of Spectroscopy is a peer-reviewed, Open Access journal that publishes original research articles as well as review articles on the theory and application of spectroscopy across all disciplines. Articles may contribute to fundamental research, or be highly applied, and must report important experimental results or relate to the development of new methods and instrumentation.
Gaudefroyite Ca4Mn3+3-x (BO3)3(CO3)(O,OH) is an unusual mineral containing both borate and carbonate groups and is found in the oxidation zones of manganese minerals, and it is black in color. Vibrational spectroscopy has been used to explore the molecular structure of gaudefroyite. Gaudefroyite crystals are short dipyramidal or prismatic with prominent pyramidal terminations, to 5 cm. Two very sharp Raman bands at 927 and 1076 cm-1 are assigned to trigonal borate and carbonate respectively. Broad Raman bands at 1194, 1219 and 1281 cm-1 are attributed to BOH in-plane bending modes. Raman bands at 649 and 670 cm-1 are assigned to the bending modes of trigonal and tetrahedral boron. Infrared spectroscopy supports these band assignments. Raman bands in the OH stretching region are of a low intensity. The combination of Raman and infrared spectroscopy enables the assessment of the molecular structure of gaudefroyite to be made.. ...
Resonance Raman spectroscopy involves laser excitation within an absorption band of the sample. Certain vibrational modes, those which couple to the electronic transition, exhibit greatly increased Raman scattering in the resulting spectrum. Sensitivity approaches that of absorption spectrophotometry, while the high resolution characteristic of vibrational spectroscopy is preserved, even in solution at room temperature. If the resonant electronic transition is associated with a site of biological activity, then the technique offers a sensitive probe for structural features of the site. Haem proteins afford particularly informative resonance Raman spectra, with a rich assortment of porphyrin ring vibrations, which can be classified and analysed via their symmetry properties. Certain of these frequencies are sensitive to the structural concomitants of spin- and oxidation-state changes of the haem group. These can be used to monitor the structural consequences of ligation or electron transfer in ...
Many international researchers joined the 11th Confocal Raman Imaging Symposium from September 29160to October1601, 2014 in Ulm, Germany. The well-established conference is a popular event at which the Raman community can present and discuss its latest scientific results. Talks from various fields of application and over 20 poster presentations...
Microorganisms accumulate molar concentrations of compatible solutes like ectoine to prevent proteins from denaturation. Direct structural or spectroscopic information on the mechanism and about the hydration shell around ectoine are scarce. We combined surface plasmon resonance (SPR), confocal Raman spectroscopy, molecular dynamics simulations, and density functional theory (DFT) calculations to study the local hydration shell around ectoine and its influence on the binding of a gene-S-protein (G5P) to a single-stranded DNA (dT(25)). Due to the very high hygroscopicity of ectoine, it was possible to analyze the highly stable hydration shell by confocal Raman spectroscopy. Corresponding molecular dynamics simulation results revealed a significant change of the water dielectric constant in the presence of a high molar ectoine concentration as compared to pure water. The SPR data showed that the amount of protein bound to DNA decreases in the presence of ectoine, and hence, the protein-DNA ...
Abstract: The A- and B-band electronic excitations and the excited state structural dynamics of 6-N,N-dimethyladenine (DMA) were studied by resonance Raman spectroscopy and density functional theory calculations. The πH→πL* transition is the main part of the A-band absorption and its calculated oscillator strength occupies 79% of the A-band absorption. n→Ryd and πH→Ryd transitions where Ryd denotes the diffuse Rydberg orbital play important roles in the B-band electronic transitions and their calculated oscillator strengths occupy about 62% of the B-band absorption. The oscillator strength for the πH→πL* transition, which dominates the A-band electronic transition only occupies about 33% of the B-band absorption. The foundamental vibrations of the purine ring deformation stretch plus the C8H/N9H bend mode ν23 and the 5 member ring deformation stretch plus the C8H bend mode ν13, and their overtones and combination bands occupy most of the A-band resonance Raman intensities. ...
While SERS can be performed in colloidal solutions, today the most common method for performing SERS measurements is by depositing a liquid sample onto a silicon or glass surface with a nanostructured noble metal surface. While the first experiments were performed on electrochemically roughened silver,[6] now surfaces are often prepared using a distribution of metal nanoparticles on the surface[20] as well as using lithography[21] or porous silicon as a support.[22][23] Two dimensional silicon nanopillars decorated with silver have also been used to create SERS active substrates.[24] Applying a thin film of silver onto wafers of silicon, through a day-long immersion in a saturated solution of silver nitrate in n-octanol, is a widely accepted method to prepare a surface-enhanced Raman scattering substrate.[25] The most common metals used for plasmonic surfaces are silver and gold; however, aluminum has recently been explored as an alternative plasmonic material, because its plasmon band is in the ...
This perspective presents an overview of single-molecule surface-enhanced Raman scattering (sm-SERS). Our overview is organized as a brief theoretical background, discussion of the factors that enhance SERS, various experimental preparations for inserting a single molecule in a hot spot, recent sm-SERS exper Plasmonics and spectroscopy
The Raman Spectra are available as complete collection of 16898 spectra or as application oriented sublibraries. Click on the library name to display details ...
The |i|Journal of Biomedical Optics|/i| (JBO) publishes peer-reviewed papers on the use of novel optical systems and techniques for improved health care and biomedical research.
On the instrumentation side, we develop multimodal nonlinear microscopy and micro-spectroscopy technologies using ultra-short laser pulses (from 10 fs to ps), possibly synchronized (using electronic synchronization or OPOs). Special attention is given to coherent Raman scattering modalities such as coherent anti-Stokes Raman scattering (CARS ) and stimulated Raman scattering (SRS) for label-free vibrational microscopy and micro-spectroscopy.. ...
DESCRIPTION (provided by applicant): Fluorescence imaging is the current major optical method for cell and tissue analysis. It relies on the use of fluorescent molecular probes which are either expressed by genes which have been modified, or are tagged onto molecules of interest. The modification can interfere with normal function and hamper the interpretation of experimental results. Furthermore, the fluorophores themselves are subject to photobleaching which results in limited imaging time and prevents long term studies. Coherent anti-Stokes Raman scattering (CARS) microscopy is a nonlinear optical imaging technique that allows high-speed vibrational imaging of molecules. CARS microscopy offers several unique advantages: (a) CARS imaging is label-free andnon-destructive. (b) The nonlinear dependence on excitation intensity ensures that the CARS signal is only generated in the focal center, providing an inherent sub-micron 3D spatial resolution. (c) CARS imaging offers intrinsic chemical ...
Femtochemistry IX: Femtochemistry, Femtobiology, and Femtophysics - Frontries in Ultrafast Science and Technology, Beijing, China, 8-13 August 2009, p. 111 P-43 ...
We introduce a novel setup combining a micro-Raman spectrometer with external optical tweezers, suitable for resonance Raman studies of single functional trapped cells. The system differs from earlier setups in that two separate laser beams used for trapping and Raman excitation are combined in a double-microscope configuration. This has the advantage that the wavelength and power of the trapping and probe beam can be adjusted individually to optimize the functionality of the setup and to enable the recording of resonance Raman profiles from a single trapped cell. Trapping is achieved by tightly focusing infrared (IR) diode laser radiation (830 nm) through an inverted oil-immersion objective, and resonance Raman scattering is excited by the lines of an argon:krypton ion laser. The functionality of the system is demonstrated by measurements of trapped single functional erythrocytes using different excitation lines (488.0, 514.5, and 568.2 nm) in resonance with the heme moiety and by studying ...
A revealing signature: The glycan structure of intact yeast external invertase, a high-mannose glycoprotein used as biocatalyst, was investigated by using Raman optical activity (ROA) spectroscopy. The conformational preferences present in mannose-containing di- and trisaccharides were found to be preserved in the glycan chains, with secondary polpeptide backbone structure suppressed.. ...
We have explored the un-enhanced Raman spectra of both single and twin electrodes in 3.5% NaCl solution (at ambient temperatures) over a range of applied potentials (between 20 and 200 mV) and times (between 0 and 5 h). Under these conditions, we observed the initial formation of green rust (hydroxychlorides and/or hydroxycarbonates), followed by the formation of magnetite (Fe3O4) and then a mixture of the alpha- and gamma-FeOOH (goethite and lepidocrocite, respectively). These data are consistent with a model for corrosion during which the initially formed magnetite is either covered, or replaced, by layers of the FeOOH oxidation products. Fitting of the data as a function of time and potential shows that, although the product range is independent of potential, the relative kinetics of formation of magnetite and its subsequent conversion to the gamma-FeOOH were potential and time dependent. Analysis by mapping of the dry corroded surface showed a variety of species, including green rust, some ...
Surface enhanced Raman scattering (SERS) is a well-established spectroscopic technique that requires nanoscale metal structures to achieve high signal sensitivity. While most SERS substrates are manufactured by conventional lithographic methods, the development of a cost-effective approach to create nanostructured surfaces is a much sought-after goal in the SERS community. Here, a method is established to create controlled, self-organized, hierarchical nanostructures using electrohydrodynamic (HEHD) instabilities. The created structures are readily fine-tuned, which is an important requirement for optimizing SERS to obtain the highest enhancements. HEHD pattern formation enables the fabrication of multiscale 3D structured arrays as SERS-active platforms. Importantly, each of the HEHD-patterned individual structural units yield a considerable SERS enhancement. This enables each single unit to function as an isolated sensor. Each of the formed structures can be effectively tuned and tailored to ...
The CARS process can be physically explained by using either a classical oscillator model or by using a quantum mechanical model that incorporates the energy levels of the molecule. Classically, the Raman active vibrator is modeled as a (damped) harmonic oscillator with a characteristic frequency of ωv. In CARS, this oscillator is not driven by a single optical wave, but by the difference frequency (ωp-ωS) between the pump and the Stokes beams instead. This driving mechanism is similar to hearing the low combination tone when striking two different high tone piano keys: your ear is sensitive to the difference frequency of the high tones. Similarly, the Raman oscillator is susceptible to the difference frequency of two optical waves. When the difference frequency ωp-ωS approaches ωv, the oscillator is driven very efficiently. On a molecular level, this implies that the electron cloud surrounding the chemical bond is vigorously oscillating with the frequency ωp-ωS. These electron motions ...
There has been a surge of interest in the surface-enhanced Raman scattering (SERS) of p-aminothiophenol (PATP), since its SERS spectra are dependent on the measurement conditions. However, there is a dispute over the origin of the so-called b2 modes in SERS spectrum of PATP recently. Some researchers propose that these bands come from selective chemical enhancement, while others conclude that these bands are due to the ag modes of p,p-dimercaptoazobenzene (DMAB) produced from PATP by surface photoreaction. To solve this problem, we have studied the SERS spectra of PATP on Au and Ag nanoparticles by in situ measurement under various conditions. The results proved that the b2 modes are not due to PATP but due to the ag modes of DMAB. The key of the method is to ensure the SERS spectra taken from the same point in reduplicative measurements. The result showed that the stable SERS spectrum of PATP was essentially from DMAB. The reversibility of the PATP SERS spectra in previous studies is due to ...
In the pharmaceutical industry, novel analytical techniques are required to gain important insights about new drug candidates and their formulations as early as possible. This information can be used to develop more efficient, safe and also economically profitable medicines. Microscopy techniques can be used for example to follow the fate of nanoparticles in cells and tissues, but also to monitor the changes in solid-state forms of drug molecules during drug development and storage. The overall aim of the Thesis was to evaluate the capability of non-linear optical imaging, especially coherent anti-Stokes Raman scattering (CARS), second harmonic generation and sum-frequency generation (SHG and SFG) microscopies, in pharmaceutical applications including imaging of live cells, nanoparticle cellular uptake and pharmaceutical solid-state analysis. First, the capability of CARS microscopy to image live cell cultures on pharmaceutically relevant membrane inserts was evaluated. It was found that, ...
Bronder, Helen S., "Low Frequency Resonance Raman Study of Myoglobin Derivatives" (1992). Masters Theses (1922-2009) Access restricted to Marquette Campus. 2441 ...
article{2111824, abstract = {The feasibility of Raman spectroscopy in combination with partial least-squares (PLS) regression for the determination of individual or grouped trans-monounsaturated fatty acids (trans-MUFA) and conjugated linoleic acids (CLA) in milk fat is demonstrated using spectra obtained at two temperature conditions: room, temperature and after freezing at -80 degrees C. The PLS results displayed capability for direct semiroutine quantification of several individual CLA (cis-9,trans-11 and trans-10,cis-12 C18:2) and trans-MUFA (trans-4-15 C18:1) in minor concentrations (below 1.0 g/100 g of milk fat). Calibration models were based on reference data cross-correlation or determined by specific scattering signals in the Raman spectra. Distinct bands for trans-MUFA (1674 cm(-1)) and CLA (1653 cm(-1)) from the trans isolated and cis,trans conjugated C=C bonds were identified, as well as original evidence for the temperature effect (new bands, peak shifts, and higher intensities) on ...
The radical cation and the two lowest excited singlet Rydberg states of DABCO (1,4-diazabicyclo[2.2.2]octane) are studied. Experimentally, the radical cation of DABCO is generated by either laser flash photolysis in solution at room temperature or by gamma-irradiation in a Freon glass at 77 K, and its electronic absorption and resonance Raman spectra in these two media are reported. The present resonance Raman spectra differ substantially from previous reports given in the Literature, and it is concluded that a number of bands attributed previously to the DABCO radical cation are due to other species. Theoretically, the absorption and resonance Raman spectra are interpreted on the basis of density functional theory (DFT; B3LYP/6-31G(d)) calculations and wave packet propagation methods. The same DFT calculations are used to interpret excitation and multiphoton ionization spectra of the two lowest singlet Rydberg states, making use of the close similarity between a Rydberg state and its ionic ...
The formation of biofilms by diverse bacteria isolated from contaminated soil and groundwater on model substrata with different surface properties was assessed in a multifactorial screen. Diverse attachment phenotypes were observed as measured by crystal violet dye retention and confocal laser scanning microscopy (CLSM). Bulk measurements of cell hydrophobicity had little predictive ability in determining whether biofilms would develop on hydrophobic or hydrophilic substrata. Therefore selected pairs of bacteria from the genera Rhodococcus, Pseudomonas and Sphingomonas that exhibited different attachment phenotypes were examined in more detail using CLSM and the lipophilic dye, Nile Red. The association of Rhodococcus sp. cell membranes with lipids was shown to influence the attachment properties of these cells, but this approach was not informative for Pseudomonas and Sphingomonas sp. Confocal Raman Microspectroscopy of Rhodococcus biofilms confirmed the importance of lipids in their formation ...
Gerald McEwen, Yangzhe Wu, Mingjie Tang, Xiaojun Qi, Zhongmiao Xiao, Sherry Baker, Tian Yu, Timothy Gilbertson, Daryll DeWald, and Anhong Zhou, "Subcellular Spectroscropic Markers, Topography and Nanomechanics of Human Lung Cancer and Breast Cancer Cells Examined by Combined Confocal Raman Microspectroscopy and Atomic Force Microscopy," Analyst, Vol. 138, No. 3, pp. 787-797, 2013. DOI: 10.1039/c2an36359c. Epub 2012 Nov 27. Work under VPR Research Catalyst (RC) Seed Grant. [PDF ...
Non-melanoma skin cancer (NMSC) belongs to the most frequent human neoplasms. Its exposed location facilitates a fast ambulant treatment. However, in the clinical practice far more lesions are removed than necessary, due to the lack of an efficient pre-operational examination procedure: Standard imaging methods often do not provide a sufficient spatial resolution. The demand for an efficient in vivo imaging technique might be met in the near future by non-linear microscopy. As a first step towards this goal, the appearance of NMSC in various microspectroscopic modalities has to be defined and approaches have to be derived to distinguish healthy skin from NMSC using non-linear optical microscopy. Therefore, in this contribution the appearance of ex vivo NMSC in a combination of coherent anti-Stokes Raman scattering (CARS), second harmonic generation (SHG) and two photon excited fluorescence (TPEF) imaging-referred as multimodal imaging-is described. Analogous to H&E staining, an overview of the distinct
Infection with the dengue virus is currently clinically detected according to different biomarkers in human blood plasma, commonly measured by enzyme linked immunosorbent assays, including non-structural proteins (Ns1), immunoglobulin M (IgM) and immunoglobulin G (IgG). However, there is little or no mutual correlation between the biomarkers, as demonstrated in this study by a comparison of their levels in samples from 17 patients. As an alternative, the label free, rapid screening technique, Raman spectroscopy has been used for the characterisation/diagnosis of healthy and dengue infected human blood plasma samples. In dengue positive samples, changes in specific Raman spectral bands associated with lipidic and amino acid/protein content are observed and assigned based on literature and these features can be considered as markers associated with dengue development. Based on the spectroscopic analysis of the current, albeit limited, cohort of samples, Principal Components Analysis (PCA) coupled
Raman spectroscopy offers several advantages for microscopic analysis. Since it is a scattering technique, specimens do not need to be fixed or sectioned. Raman spectra can be collected from a very small volume (, 1 µm in diameter); these spectra allow the identification of species present in that volume. Water does not generally interfere with Raman spectral analysis. Thus, Raman spectroscopy is suitable for the microscopic examination of minerals, materials such as polymers and ceramics, cells and proteins. A Raman microscope begins with a standard optical microscope, and adds an excitation laser, a monochromator, and a sensitive detector (such as a charge-coupled device (CCD), or photomultiplier tube (PMT)). FT-Raman has also been used with microscopes.. In direct imaging, the whole field of view is examined for scattering over a small range of wavenumbers (Raman shifts). For instance, a wavenumber characteristic for cholesterol could be used to record the distribution of cholesterol within ...
Raman spectroscopy offers several advantages for microscopic analysis. Since it is a scattering technique, specimens do not need to be fixed or sectioned. Raman spectra can be collected from a very small volume (, 1 µm in diameter); these spectra allow the identification of species present in that volume. Water does not generally interfere with Raman spectral analysis. Thus, Raman spectroscopy is suitable for the microscopic examination of minerals, materials such as polymers and ceramics, cells and proteins. A Raman microscope begins with a standard optical microscope, and adds an excitation laser, a monochromator, and a sensitive detector (such as a charge-coupled device (CCD), or photomultiplier tube (PMT)). FT-Raman has also been used with microscopes.. In direct imaging, the whole field of view is examined for scattering over a small range of wavenumbers (Raman shifts). For instance, a wavenumber characteristic for cholesterol could be used to record the distribution of cholesterol within ...
New Technology for IR and Raman Spectral Identification Broadcast on December 2, 2014 This webinar is now available on-demand. If you have already registered for this event, please login using the link provided in your registration confirmation email. Register now Scientists using spectroscopy to identify unknown compounds need the right answers,...
Measurement and Simulation of Spontaneous Raman Scattering Spectra in High-Pressure, Fuel-Rich H-Air Flames by (ISBN: 978-1-289-28865-5); Published by Creative Media Partners, LLCin Aug 2013. Compare book prices on Bookwire.com to buy books from the lowest price among top online book retailers
Science & Technology, Physical Sciences, Life Sciences & Biomedicine, Chemistry, Applied, Food Science & Technology, Chemistry, CHEMISTRY, APPLIED, FOOD SCIENCE & TECHNOLOGY, egg albumen, whey, protein, gelation, rheology, Raman spectroscopy, BOVINE SERUM-ALBUMIN, BLOOD-PLASMA PROTEINS, BETA-LACTOGLOBULIN, GLOBULAR-PROTEINS, SECONDARY STRUCTURE, FUNCTIONAL-ASPECTS, HEAT DENATURATION, CYSTINE LINKAGES, GELATION, CONFORMATION ...
Microporous solids are a widely used material in adsorption, storage and catalysis. In this thesis, the crystallization of the silcoaluminaphosphate DNL-6 was characterized using powder X-ray diffraction and solid state nuclear magnetic resonance. Two crystallization routes of the SAPO DNL-6 were studied, which are the hydrothermal method and the dry-gel conversion method. Both methods followed the same crystallization pathway and showed a layered intermediate that is then transformed into DNL-6. The reaction requires two templating agents to create the RHO topology and silicon substitutes into the framework by replacing single phosphorous atoms. This thesis contains the conformational analysis of halocarbons adsorbed into different metal-organic frameworks has also been studied using FT-Raman spectroscopy. 1,2-dichloroethane and 1-bromo-2-chloroethane were adsorbed into MIL-53, MIL-68, MIL-53NH2, while chlorocyclohexane was adsorbed in MIL-53. For non-polar frameworks the main guest-host interactions
In the present study we report the synthesis, crystal structure and Raman spectroscopy studies of Na1-xKxPb4(VO4)(3) orthovanaclates solid solutions (0 ,= x ,= 1). Rielveld refinements showed that this solid solution is continuous adopting P6(3)/m (no. 176) space group. Some of Pb(II) cations are located in the (6 h) sites. The ninefold coordination sites (4f) are equally occupied by the other lead cations and the K+ and Na+ monovalent ions. The structure can be described as built up from [VO4](3-) tetrahedral and Ph2+ of sixfold coordination cavities (6 h positions), which delimit void hexagonal tunnels running along [0 0 1]. These tunnels are connected by cations of mixed sites (4f) half occupied by Pb(II) and half by Na+/K+ mixed cations. The existence of this type of lacunar apatite seems to be conditioned by the presence of lone pair cations Pb(II). Raman spectra of all the compositions are similar and show some linear shifts in band positions as a function of the composition toward high ...
분광기는 기초과학인 물리학과 화학에서는 기본장비로 활용되지만 응용분야인 바이오,나노,환경,재료 등 시험평가 부분에서는 Raman(라만),Photo Luminescence(광발광),Fluorescence(형광발광)시스템으로 핵심적인 역할을 한다. 이에 따라 동우옵트론은 마이크로 라만(Micro Raman) 공촛점 라만(Confocal Raman) PL/Raman mapping 시스템을 개발,이를 국내외에 공급함으로써 여러분야 발전에 이바지 하고 있다.. ...
MICHIGAN STATE (US) - Using laser microscopes that deploy rapid, ultra-short pulses to identify molecules, doctors may soon have the tools to perform painless skin cancer biopsies.. To test for skin cancer, patients today must endure doctors cutting away a sliver of skin and anxiously await the lab results.. "Smart lasers allow us to selectively excite compounds-even ones with small spectroscopic differences," says Marcos Dantus, a chemistry professor at Michigan State University. "We can shape the pulse of the lasers, excite one compound or another based on their vibrational signatures, and this gives us excellent contrast.". Dantus and co-author Sunney Xie of Harvard University report their findings in the journal Nature Photonics.. In the past, researchers could approach this level of contrast by introducing fluorescent compounds. With the breakthrough using stimulated Raman scattering microscopy, fluorescent markers are unnecessary.. "Label-free molecular imaging has been the holy grail in ...
Raman scattering and its particular effect, surface-enhanced Raman scattering (SERS), are whole-organism fingerprinting spectroscopic techniques that gain more and more popularity in bacterial detection. In this work, two relevant Gram-positive bacteria species, Lactobacillus casei (L. casei) and Listeria monocytogenes (L. monocytogenes) were characterized based on their Raman and SERS spectral fingerprints. The SERS spectra were used to identify the biochemical structures of the bacterial cell wall. Two synthesis methods of the SERS-active nanomaterials were used and the recorded spectra were analyzed. L. casei and L. monocytogenes were successfully discriminated by applying Principal Component Analysis (PCA) to their specific spectral data.
Buy XploRA INV, Raman Spectrometer with Automation Features or other Raman spectrometer products from Acal BFi NL. Get a quote from Europes leading industrial electronics and photonics specialist today.
1D06: Sensory mechanism of oxygen sensor FixL from Rhizobium meliloti: crystallographic, mutagenesis and resonance Raman spectroscopic studies
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Researchers at the University of Victoria in British Columbia, Canada, have demonstrated that a wet chemistry technique for depositing layers of gold
Trace chemical analysis by Surface-Enhanced Raman Spectroscopy (SERS) is made quick and easy with sample vials coated with a patented SERS-active sol-gel. A solution containing the chemical of interest is simply injected into the vial, which is placed in a Raman spectrometer sample compartment, the spectrum is recorded, and science moves forward.. The measured SER spectrum consists of a wavelength distribution of bands corresponding to molecular vibrations specific to the chemical being analyzed. This allows identification of numerous chemicals, biochemicals and pharmaceuticals. In most cases a simple calibration allows quantifying the chemicals by the intensity of the Raman spectral bands.. ...
Symbiotic rhizobia in legumes account for a large portion of nitrogen fixation in the biosphere. Nitrogen fixation is an energy-demanding process requiring tight control of metabolism and redox state. It is of great interest to understand the bacteroid differentiation process and the roles of energy storage molecules, such as glycogen and polyhydroxybutyrate (PHB), in maintaining the Rhizobium-legume symbioses. Traditional biochemical assays for checking phenotypic changes of mutants require a large volume of starting materials, which is difficult for unculturable, terminally differentiated bacteroids. Here we present a label-free technique that allows the identification and characterization of phenotypic changes of bacteria at the single-cell level. This work demonstrates the application of single-cell Raman spectra (SCRS) to differentiate Rhizobium leguminosarum bv. viciae wild-type and mutants under different conditions. We found symbiotically differentiated bacteroids and free-living bacteria
CrossRef 11. Zhang W, Fischer H, Schmid T, Zenobi R, Martin OJF: Mode-selective surface-enhanced Raman spectroscopy using nanofabricated plasmonic dipole antennas. J Phys Chem C 2009, 113:14672-14675.CrossRef 12. Dhawan A, Zhang Y, Yan F, Gerhold M, Vo-Dinh T: Nano-engineered surface-enhanced Raman scattering (SERS) substrates with patterned structures on the distal end of optical fibers. Proc SPIE Temsirolimus manufacturer 2008, 6869:68690G.CrossRef 13. Bai J, Qin Y, Jiang C, Qi L: Polymer-controlled synthesis. of click here silver nanobelts and hierarchical nanocolumns. Chem Mater 2007, 19:3367-3369.CrossRef 14. Liu R, Sen A: Unified synthetic approach to silver nanostructures by galvanic displacement reaction on copper: from nanobelts to nanoshells. Chem Mater 2012, 24:48-54.CrossRef. 15. Liu L, Yoo selleck products S-H, Lee SA, Park S: Electrochemical growth of silver nanobelts in cylindrical alumina nanochannels. Cryst Growth Des 2011, 11:3731-3734.CrossRef 16. Chen H, Simon F, Eychmüller ...
Infrared Spectroscopy of the Electrode-Electrolyte Solution Interface (A. Bewick and S. Pons). Infrared Spectral Studies of DNA Conformations (E. Taillandier, et al.). Vibrational Analysis of the Retinal Isomers (B. Curry, et al.). A Unified View of Raman, Resonance Raman and Fluorescence Spectroscopy (and Their Analogues in Two-photon Absorption) (D. Lee and A. C. Albrecht). Magnetic Raman Optical Activity (L. D. Barron and J. Vrbanovich). The Resonance Raman Effect and Depolarisation in Vibrational Raman Scattering (H. Hamaguchi). Low Frequency Depolarised Light Scattering from Liquids and Solutions (D. W. James).
In the course of work on the Raman spectra of solids at low temperatures, we have succeeded in photographing the spectrum of the light scattered by solidified nitrogen peroxide (N2O4), at a temperature of about - 80°C.
This review presents an introduction to Raman scattering and describes the various Raman spectroscopy, Raman microscopy, and chemical imaging techniques that have demonstrated utility in biocolloidal self-assemblies, pharmaceutical drug delivery systems, and pulmonary research applications. Recent Raman applications to pharmaceutical aerosols in the context of pulmonary inhalation aerosol delivery are discussed.
Raman spectroscopy has long been applied in geoscience, for example for the identification and characterization of minerals, or in the observation of mineral phase transitions in high and ultra-high pressure/temperature experiments. In most cases because measurements have been carried out in a micro-Raman set up very little detail on the spatial distribution and association components or mineral phases, or chemical variation could be observed. In this application note from WITec, by means of Con
Characterization of the Chemical Nature of the Black Ink in the Manuscript of The Gospel of Jesuss Wife through Micro-Raman Spectroscopy - Volume 107 Issue 2 - James T. Yardley, Alexis Hagadorn
Department of Chemistry, UBC Faculty of Science. Vancouver Campus. 2036 Main Mall. Vancouver, BC Canada V6T 1Z1. Tel: 604.822.3266. Fax: 604.822.2847. ...
Department of Chemistry, UBC Faculty of Science. Vancouver Campus. 2036 Main Mall. Vancouver, BC Canada V6T 1Z1. Tel: 604.822.3266. Fax: 604.822.2847. ...
Nanoplasmonics has raised much concern on tailoring the strong optical fields near noble metal nanostructures. In particular, surface-enhanced Raman Scattering (SERS) can take the full benefits of nanoplasmonics for providing one of the most highly sensitive biochemical sensing techniques. This sensitivity is used to identify biochemical molecules even at single molecule level. This technique does not require fluorescent labeling. For decades, thousands of plasmonic nanoparticles or nanostructures mounted on substrates have been reported for plasmonics-driven SERS. However, previous work overlooks consideration of the quantitative investigation between plasmon resonance and SERS signals. This oversight has been due to available methodology.. Universal correlations between plasmon resonance and SERS has recently been described by the research of Ki-Hun Jeong (see, Kang et al.1) in Journal Advanced Materials - This observation was successfully enabled by deformable nanoplasmonic membrane, i.e., ...
Circulating tumor cells (CTCs) are a new type of breast cancer molecular marker. CTCs in peripheral blood originate from breast cancer (primary and metastatic lesions) shedding. Utilization of CTCs as novel and noninvasive tests for diagnosis confirmation, therapy selection, and cancer surveillance is a rapidly growing area of interest. At present, there is a great challenge to create an effective platform that can isolate these cells, as they are extremely rare: only 1-10 CTCs are present in a 7.5mL of a cancer patients peripheral blood. The majority of the CTC capture methods are based on EpCAM expression as a surface marker of tumor-derived cells. However, EpCAM protein expression levels can be significantly down regulated during cancer progression as a consequence of the process of epithelial to mesenchymal transition. Although many technologies have been reported to achieve the capture and counting of CTCs, these methods study little information of cells and limited biological information ...
Ministry of Human Resource Development (MHRD) under its National Mission on Education through Information and Communication Technology (NMEICT) has initiated the National Digital Library of India (NDL India) pilot project to develop a framework of virtual repository of learning resources with a single-window search facility. Filtered and federated searching is employed to facilitate focused searching so that learners can find out the right resource with least effort and in minimum time. NDL India is designed to hold content of any language and provides interface support for leading Indian languages. It is being arranged to provide support for all academic levels including researchers and life-long learners, all disciplines, all popular form of access devices and differently-abled learners. It is being developed to help students to prepare for entrance and competitive examination, to enable people to learn and prepare from best practices from all over the world and to facilitate researchers to ...
A standard burner for confined swirling natural gas flames is presented which was developed within the German TECFLAM cooperation. The aims of the TECFLAM research program are the establishment of an...
Title: Detection of Protein Phosphorylation Using Electrically Amplified Surface-Enhanced Raman Spectroscopy. Speaker: Yi Chen, Graduate Student in Electrical and Computer Engineering with Prof. Logan Liu. The interaction of biomolecules and solid-state nanomaterials at the bio-nano interfaces is a long-lasting research topic in nanotechnology. Historically, fundamental problems, such as the electron transfer, energy transfer, and plasmonic interaction at the bio-nano interfaces, have been intensively studied, and revolutionary technologies, such as molecular electronics, peptide chips, nanoplasmonic sensors, have been created. With the combined effort of molecular dynamics simulation and surface-enhanced Raman spectroscopy, we studied the external electric field-induced conformation changes of dodecapeptide probes tethered to a nanostructured metallic surface. Through this study, we demonstrated a reversible manipulation of the biomolecule conformations as well as an in situ eletro-optical ...
Link to Pubmed [PMID] - 18177032. J Phys Chem B 2008 Jan;112(4):1282-9. Circular dichroism (CD) and Raman scattering were applied to the aqueous solution of minimalist LK peptides constructed with successive KL repeats leading to the following generic primary sequence: (KL)nK. Three peptides of this family, a 3-mer (n=1), a 9-mer (n=4), and a 15-mer (n=7), are analyzed in this report. Raman spectra of the 3-mer (KLK, a random chain) and its labile-hydrogen deuterated species yield a set of interesting information for analyzing longer peptides of this series. Although the CD spectrum of the 9-mer (KLKLKLKLK) reveals a signal traditionally assigned to a random structure, the corresponding Raman spectrum allows finding a mixture of conformations in solution, adopting predominantly beta-type structures. This fact proves the utility of Raman spectroscopy to eliminate eventual ambiguity concerning conformational assignments in peptides based only on the use of CD technique. Finally, the 15-mer ...
By enabling Tip-Enhanced Raman Spectroscopy , the brand new IRIS TERS probe guidelines provide users a full path to non-destructive, label-free chemical detection at the nanoscale. As razor-sharp, solid-steel cones, IRIS TERS Probes are created to deliver the best Raman enhancement, which translates to highest sensitivity and spatial resolution. Together with Brukers Innova-IRIS system, and third-party study Raman systems, IRIS TERS Probes may create the highest-overall performance complete commercial TERS solution. Munch, Ph.D., President, Bruker MAT Group and Bruker Nano Surfaces Division. By addressing this key gap, we are making TERS more available broadly, addressing the unmet dependence on nanochemical identification. With their proven TERS contrast capability, the IRIS TERS Probes are an expression of our commitment to moving atomic power microscopy beyond simply imaging, added David V. Continue reading →. ...
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To enable better management of viral outbreaks, diagnostic technology needs to become more rapid, sensitive and reliable. Enzyme-linked immunosorbent
High-pressure synchrotron based angle dispersive x-ray diffraction (ADXRD) studies were carried out on SmGdO{sub 3} (SGO) up to 25.7 GPa at room temperature. ADXRD results indicated a reversible pressure-induced phase transition from ambient monoclinic to hexagonal phase at ∼8.9 GPa. The observed pressure-volume data were fitted with the third order Birch-Murnaghan equation of state yielding zero pressure bulk modulus B{sub 0} = 132(22) and 177(9) GPa for monoclinic (B-type) and hexagonal (A-type) phases, respectively. Pressure dependent micro-Raman spectroscopy further confirmed the monoclinic to hexagonal phase transition at about 5.24 GPa. The mode Grüneisen parameters and pressure coefficients for different Raman modes corresponding to each individual phases of SGO were calculated using pressure dependent Raman mode analysis. ...
Abstract. K-feldspar in rocks is commonly seen as a heterogeneous mixture of mineral species and varieties with random microstructures. Most consider that observable features arise from incomplete re-equilibrations owing to slow kinetic and localized effects of aqueous fluids (catalyst), with geological environment and chemical impurities playing only a secondary role. Here, an alternative approach is explored by studying well-preserved regularities in the twin patterns of K-feldspar formed in the subsolidus stage from a historical perspective. Selected samples from granitic pegmatites were studied by polarized light optical microscopy (PLOM), electron-probe micro-analysis (EPMA), scanning (SEM) and transmission electron microscopy (TEM), cathodoluminescence imaging (CL), micro-Raman spectroscopy (MRS) and 31P nuclear magnetic resonance (NMR). We have found that the essential feature of this crystalline medium is the astounding ability to recrystallize into self-organized twin patterns. The ...
1. Glassy Anomalies in the Low-Temperature Thermal Properties of a Minimally Disordered Crystalline Solid, J. F. Gebbia, M. A. Ramos, D. Szewczyk, A. Jezowski, A. I. Krivchikov, Y. V. Horbatenko, T. Guidi, F. J. Bermejo, and J. Ll. Tamarit, Phys. Rev. Lett. 119, 215506 (2017). [URL]. 2. Thermodynamic and Kinetic Fragility of Freon 113: The Most Fragile Plastic Crystal, A. Vispa, M. Romanini, M. A. Ramos, L. C. Pardo, F. J. Bermejo, M. Hassaine, A. I. Krivchikov, J. W. Taylor, and J. Ll. Tamarit, Phys. Rev. Lett. 118, 105701 (2017). [URL]. 3. Lattice damage in 9-MeV-carbon irradiated diamond and its recovery after annealing, F. Agulló-Rueda, N. Gordillo, M. D. Ynsa, A. Maira, J. Cañas, and M. A. Ramos, Carbon 123, 334-343 (2017). [URL]. 4. Micro-Raman spectroscopy of near-surface damage in diamond irradiated with 9-MeV boron ions, F. Agulló-Rueda, M. D. Ynsa, N. Gordillo, A. Maira, D. Moreno-Cerrada, and M. A. Ramos, Diamond & Related Materials 72, 94-98 (2017). [URL]. 5. Suppression of ...
Influence of particle size and shape on the backscattering linear depolarisation ratio of small ice crystals - cloud chamber measurements in the context of contrail and cirrus ...
FT-Raman spectroscopic analysis of an Antarctic endolith - Volume 1 Issue 4 - Susana E. Jorge Villar, Howell G.M. Edwards, David D. Wynn-Williams, M. Roger Worland
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The excited state structural dynamics of phenyl isothiocyanate (PITC) after excitation to the light absorbing S{sub 2}(A′), S{sub 6}(A′), and S{sub 7}(A′) excited states were studied by using the resonance Raman spectroscopy and complete active space self-consistent field method calculations. The UV absorption bands of PITC were assigned. The vibrational assignments were done on the basis of the Fourier transform (FT)-Raman and FT-infrared measurements, the density-functional theory computations, and the normal mode analysis. The A-, B-, and C-bands resonance Raman spectra in cyclohexane, acetonitrile, and methanol solvents were, respectively, obtained at 299.1, 282.4, 266.0, 252.7, 228.7, 217.8, and 208.8 nm excitation wavelengths to probe the corresponding structural dynamics of PITC. The results indicated that the structural dynamics in the S{sub 2}(A′), S{sub 6}(A′), and S{sub 7}(A′) excited states were very different. The conical intersection point CI(S{sub 2}/S{sub 1}) were ...
3. Particle selection. Initially, all located particles are set for Raman analysis. However, they can be filtered according to the statistics results, allowing only particles which correspond to a specific size/shape to be analyzed. For example, only particles within a certain size range can be marked for Raman characterization.. 4. Raman acquisition. The full capabilities of the Raman instrument can be utilized for the Raman acquisition stage, including choice of laser wavelength, spectral resolution, confocality and mapping. Such configurable experiments ensure that optimized results can be obtained from varying sample sets with ease. The Raman spectra are displayed in a table together with the statistical parameters.. ...