Peak Intensity Ratio Research Articles

Optical constants of diamond-like carbon films formed by gas cluster ion beam assisted deposition

We investigated the refractive index (n) and extinction coefficient (k) of diamond-like carbon (DLC) films formed by gas cluster ion beam (GCIB)-assisted deposition. DLC films are classified into four types based on n and k values (at λ = 2.25 eV). We formed the nonclassified DLC film which has high n (2.4–3.0) and k (0.75–1.0) values. The Raman peak intensity ratio (I D/I G) of this film was 0.601, which corresponds to the value of a-C:H or ta-C:H. The film density was 2.71 g cm−3. The nonclassified DLC film has intermediate properties between a-C:H and ta-C:H with respect to the density and k.

The “Bi-drifting” Subpulses of PSR J0815+0939 Observed with the Five-hundred-meter Aperture Spherical Radio Telescope

We report the “Bi-drifting” subpulses observed in PSR J0815+0939 using the Five-hundred-meter Aperture Spherical radio Telescope (FAST). The observation at band from 1050 to 1450 MHz is evenly divided into two bands, i.e., the bands at center frequencies of 1150 and 1350 MHz. The mean pulse profiles and the “Bi-drifting” subpulses at these two bands are investigated. It is found that the pulse profiles at these two frequencies show four emission components, and the peak separations between four emission components decrease with the increase of frequency. In addition, the ratio of peak intensity of each component to the intensity of component IV at 1150 MHz is larger than that at 1350 MHz. We carry out an analysis of the longitude-resolved fluctuation spectrum and two-dimensional fluctuation spectrum for each emission component, and find that the P3 of components I, II and III is about 10.56, 10.57 and 10.59 s at 1150 and 1350 MHz. However, the reliable measurements of P3 of component IV and P2 for these four components were not obtained due to the low signal-to-noise ratio of observation data. The pulse energy distributions at frequencies 1150 and 1350 MHz are presented, and it is found that no nulling phenomenon has been found in this pulsar. With our observation from the FAST, the “Bi-drifting” subpulse phenomenon of PSR J0815+0939 is expanded from 400 to 1350 MHz, which is helpful for the relevant researchers to test and constrain the pulsar emission model, especially the model of “Bi-drifting” subpulse.

Double Layer Growth of ZnO Nanorods by a Low Temperature Solution Method: Synthesis and Photoluminescence Properties

In the present work, double layer Zinc Oxide (ZnO) nanorods (NRs) were fabricated hydrothermally and their photoluminescence (PL) properties were investigated. Two different recipes and their combination were used to obtain double layer vertically well-aligned ZnO NRs. These recipes include polyethylenimine (PEI) and citrate as additives in the growth solution resulting long NRs with a broad defect emission and relatively short NRs with a near band-edge ultraviolet (UV) emission, respectively. Double layer growth of long-long (LL), long-short (LS) and short-short (SS) ZnO NRs were considered. Grown samples were annealed in a forming gas atmosphere for a better quality NR structure. LL ZnO NRs (long ZnO NRs grown on a long ZnO NR layer) with a 65 µm thickness showed a broad yellow-orange PL emission and no any near band-edge UV emission was observed. LS ZnO NRs representing short ZnO NRs grown on a long ZnO NR layer (LS1= 36 µm, LS2= 48 µm and LS3= 44 µm) showed an enhanced near band-edge UV emission when compared to that of the long ZnO NRs. The UV intensity was found to decrease with the increase in thickness of the NRs in LS samples. Finally, SS ZnO NR sample, (short ZnO NRs grown on a short ZnO NR layer) which has a thickness of 33 µm, displayed a stronger near band-edge UV emission with a negligible broad emission than that of as-grown SS ZnO NRs (UV peak intensity ratio 59). This study should be important for applications where longer NRs with enhanced PL properties are strictly required.

Upcycling the barbeque grease into carbon nanomaterials

Carbon nanomaterials (CNMs) have been a remarkable material and impacted today's technology in various fields, such as enhancing agents for host material and environment-related applications. Green synthesis of CNMs gains attention as it requires low cost and less energy during the fabrications. In addition, the starting material is either environmental-friendly or a waste carbon compound that can be obtained from the household or catering industry. In this research, CNMs such as carbon nanotubes (CNTs) and graphitic carbon layers were synthesised using barbeque grease as carbon precursor via the chemical vapour deposition technique (CVD). The oil waste was analysed with gas chromatograph-mass spectrometry (GC–MS), and it showed that the oil waste contained a high amount of hydrocarbon chain such as pentadecane and 1-nonadecene, which decomposed into simple hydrocarbon bonding during the deposition and grew CNMs on the catalyst. SEM and TEM results showed that the CNTs with a diameter range of 42 ± 17 nm (outer) and 3.5 ± 0.5 nm (inner) were synthesised using the Ni catalyst. Raman and SEM revealed that the graphitic carbon layers with a D to G peak intensity ratio (I D /I G ) is 0.9898 were fabricated using Cu foil as the substrate. This research aims to discover novel and low-cost carbon precursors for the CVD system, to produce high-quality CNMs.

Fermi-Level Modulation of Chemical Vapor Deposition-Grown Monolayer Graphene via Nanoparticles to Macromolecular Dopants.

It is critical to modulate the Fermi level of graphene for the development of high-performance electronic and optoelectronic devices. Here, we have demonstrated the modulation of the Fermi level of chemical vapor deposition (CVD)-grown monolayer graphene (MLG) via doping with nanoparticles to macromolecules such as titanium dioxide nanoparticles (TiO2 NPs), nitric acid (HNO3), octadecyltrimethoxysilane (OTS) self-assembled monolayer (SAM), and poly(3,4-ethylene-dioxythiophene):polystyrene sulfonate (PEDOT:PSS). The electronic properties of pristine and doped graphene samples were investigated by Raman spectroscopy and electrical transport measurements. The right shifting of G and 2D peaks and reduction in 2D to G peak intensity ratio (I2D/IG) assured that the dopants induced a p-type doping effect. Upon doping, the shifting of the Dirac point towards positive voltage validates the increment of the hole concentration in graphene and thus downward shift of the Fermi level. More importantly, the combination of HNO3/TiO2 NP doping on graphene yields a substantially larger change in the Fermi level of MLG. Our study may be useful for the development of graphene-based high-performance flexible electronic devices.

Phase optimization algorithm for 3D particle localization with large axial depth.

We propose an optimization algorithm based on Fresnel approximation (FA) imaging to optimize an extended-axial-depth point spread function (PSF) for 3D particle localization. The transfer function efficiency of the PSF is improved by repeatedly imposing constraints in the object plane, the spatial domain, and the Fourier domain. During the iterative calculation, the effective photon number or Cramer-Rao lower bound is used as the termination condition of the iteration. The algorithm allows flexible adjustment of the peak intensity ratio of the two main lobes. Moreover, the transfer function efficiency can be balanced by increasing the weight of the modulation function of the expected PSF at each axial position. The twin-Airy (TA) PSF optimized by the FA optimization algorithm does not require complex post-processing, whereas post-processing is an essential step for the unoptimized TA-PSF. The optimization algorithm is significant for extended-axial-depth PSFs used for 3D particle localization, as it improves localization precision and temporal resolution.

A disposable ratiometric electrochemical aptasensor with exonuclease I-powered target recycling amplification for highly sensitive detection of aflatoxin B1

A disposable ratiometric electrochemical aptasensor has been constructed for highly sensitive detection of aflatoxin B1 (AFB1) with exonuclease I (Exo I)-powered cascade amplification. Specifically, the in-situ growth of Au nanoflowers (AuNFs) on indium tin oxide (ITO) surface was used to anchor methylene blue (MB) labeled the complementary DNA of aptamer. Ferrocene (Fc) labeled aptamer was then hybrid with cDNA(MB) to produce a duplex structure. Due to the rigid structure of the duplex structure, Fc molecules were close to the electrode surface while MB molecules were far away, which respectively produced a faded external response signal and an enhanced internal reference signal. When AFB1 was present in sample, the aptamers specifically bond with the targets and then detached from electrode surface, which resulted a signal-off for Fc indicators. Meanwhile, more MB molecules were close to the electrode surface owing to an increasing target concentration, which caused a signal-on for MB indicators. On this basis, the ratiometric electrochemical detection of AFB1 was achieved employing the peak current intensity ratio (IMB/IFc) as signal transducer. Moreover, Exo I was introduced to digest the detached aptamer, and the released AFB1 entered the next round of circulation which formed the target recycling and realized the signal amplification. This aptasensor exhibited a wide detection range (0.1–1000 pg mL−1) and a low detection limit (0.032 pg mL−1). We anticipate this method may find good utility in food quality control and further facilitate the development of aptasensor for other targets.

Tuning the emission of Poly (9,9-dioctylflorenyl-2,7-diyl) using one dimensional photonic band gap

Here we present fabrication of one dimensional photonic band gap structure (1D-PBG) based on periodic layers of silver and magnesium fluoride (MgF2) for tuning the emission of polyfluorene derivative, Poly(9,9-dioctylfluorenyl-2,7-diyl) (PFO). Transmittance measurements were used to characterize the photonic band gap. 1D-PBG structure with varying thickness of silver was fabricated on the back side of PFO coated glass substrate. Photoluminescence studies confirmed that blue emission was enhanced while the secondary peaks were suppressed. Photoluminescence spectra shows that the blue to green peak intensity ratio was improved by 1.7 times approximately with PBG. These type of PBG structures can be used to enhance the color purity of PFO based blue organic light emitting diodes. Copyright © 2017 VBRI Press.

Investigation of per- and polyfluoroalkyl substances (PFAS) in soils and sewage sludges by fluorine K-edge XANES spectroscopy and combustion ion chromatography

For the first time, fluorine K-edge X-ray absorption near-edge structure (XANES) spectroscopy was applied to detect per- and polyfluoroalkyl substances (PFAS) in various soil and sewage sludge samples. The method can be used to determine the speciation of inorganic and organic fluorides, without pre-treatment of solid samples. Therefore, XANES spectra of several inorganic fluorides as well as selected fluorinated organic compounds were recorded. While inorganic fluorides partially exhibit a variety of sharp spectral features in the XANES spectrum, almost all inspected organofluorine compounds show two distinct broad features at 688.5 and 692.0 eV. Moreover, the peak intensity ratio 688.5 eV/692.0 eV in the PFAS XANES spectrum can be inversely correlated to the chain length of the perfluoro sulfonic acid group. The detection of targeted PFAS by bulk-XANES spectroscopy in combination with linear combination fitting in soils and sewage sludges was not applicable due to the low organic fluorine to total fluorine ratio of the samples (0.01–1.84%). Nonetheless, direct analysis of pure PFAS revealed that analysis of organofluorine species might be achieved in higher concentrated samples. Furthermore, quantitative measurements by combustion ion chromatography (CIC) evaluated as sum parameters extractable organically bound fluorine (EOF) and total fluorine (TF) emphasize that besides soils, sewage sludges are a significant source of organic fluorine in agriculture (154–7209 µg/kg).

Can monodisperse microbubble-based three-dimensional contrast-enhanced ultrasound reduce quantitative heterogeneity? An in vitro study

Heterogeneity within the tumor may cause large heterogeneity in quantitative perfusion parameters. Three-dimensional contrast-enhanced ultrasound (3D-CEUS) can show the spatial relationship of vascular structure after post-acquisition reconstruction and monodisperse bubbles can resonate the ultrasound pulse, resulting in the increase in sensitivity of CEUS imaging.To evaluate whether the combination of 3D-CEUS and monodisperse microbubbles could reduce the heterogeneity of quantitative CEUS.Three in vitro perfusion models with perfusion volume ratio of 1:2:4 were set up. Both quantitative 2D-CEUS and 3D-CEUS were used to acquire peak intensity (PI) with 2 kinds of ultrasound agents. One was a new kind of monodisperse bubbles produced in this study, named Octafluoropropane-loaded cerasomal microbubbles (OC-MBs), the other was SonoVue®. The coefficient of variation (CV) was calculated to evaluate the cross-sectional variability. Pearson's correlation analysis was used to assess the correlation between weighted PIs (average of PIs of 3 different planes) and perfusion ratios.The average CVs of quantitative 3D-CEUS was slightly lower than that of 2D-CEUS (0.41 ±0.17 compared to 0.55 ±0.26, p = 0.3592). As for quantitative 3D-CEUS, the PI of the OC-MBs has shown better stability than that of SonoVue®, but without a significant difference (average CVs: 0.32 ±0.19 compared to 0.50 ±0.10, p = 0.0711). In the 2D-CEUS condition, the average CVs of OC-MBs group and SonoVue® group were 0.68 ±0.15 and 0.41 ±0.17 (p = 0.2747). As for 3D-CEUS condition, using OC-MBs group and SonoVue®, the r-values of the weighted PI and perfusion ratio were 0.8685 and 0.5643, respectively, while that of 2D-CEUS condition were 0.7760 and 0.3513, respectively.Our in vitro experiments showed that OC-MBs have the potential in acquiring more stable quantitative CEUS value, as compared to the SonoVue® in 3D-CEUS condition. The combination of 3D-CEUS and OC-MBs can reflect perfusion volume more precisely and may be a potential way to reduce quantitative heterogeneity.

Luminescence Ratiometric Nanothermometry Regulated by Tailoring Annihilators of Triplet–Triplet Annihilation Upconversion Nanomicelles

AbstractTriplet–triplet annihilation (TTA) upconversion is a special non‐linear photophysical process that converts low‐energy photons into high‐energy photons based on sensitizer/annihilator pairs. Here, we constructed a novel luminescence ratiometric nanothermometer based on TTA upconversion nanomicelles by encapsulating sensitizer/annihilator molecules into a temperature‐sensitive amphiphilic triblock polymer and obtained good linear relationships between the luminescence ratio (integrated intensity ratio of upconverted luminescence peak to the downshifted phosphorescence peak) and the temperature. We also found chemical modification of annihilators would rule out the interference of the polymer concentration and stereochemical engineering of annihilators would readily regulate the thermal sensitivity.

Luminescence Ratiometric Nanothermometry Regulated by Tailoring Annihilators of Triplet–Triplet Annihilation Upconversion Nanomicelles

AbstractTriplet–triplet annihilation (TTA) upconversion is a special non‐linear photophysical process that converts low‐energy photons into high‐energy photons based on sensitizer/annihilator pairs. Here, we constructed a novel luminescence ratiometric nanothermometer based on TTA upconversion nanomicelles by encapsulating sensitizer/annihilator molecules into a temperature‐sensitive amphiphilic triblock polymer and obtained good linear relationships between the luminescence ratio (integrated intensity ratio of upconverted luminescence peak to the downshifted phosphorescence peak) and the temperature. We also found chemical modification of annihilators would rule out the interference of the polymer concentration and stereochemical engineering of annihilators would readily regulate the thermal sensitivity.

Correlation and Difference Between Raman Spectral Characteristic and Feature Evaluation for Leukocytes and Tumor Cells.

Tumor detection supported by Raman spectroscopy is becoming increasingly popular, yet the relevance of spectral variation and feature selection retains unclear. Here we determined the correlation and difference between spectral characteristic and feature evaluation for leukocytes and tumor cells. Some peaks were found to show noticeable spectral differences, and their intensity distributions were investigated, finding using log-normal distribution to describe Raman intensity pattern may be more appropriate. Further the importance of all Raman features was calculated, where some other peak features occupied the top status. By surveying the intensity variation and feature evaluation for those peaks, we concluded the peak with the highest importance does not correspond to the peak location with the most noticeable intensity difference in spectra. Moreover, the peak intensity ratio of I1517/I719 associated with protein to nucleic acid level presented the maximum separation, thus, it can be recognized as a special indicator to develop an alternative cancer detection. It is inspiring to introduce advanced statistical models into bio-spectroscopic fields but those intrinsic spectral variations rather than classification performance should be valued. Our explorations can provide possibilities to reveal the essences within tumor carcinogenesis based on Raman spectroscopy, further overwhelming the obstacles during the translation into clinical applications.

Investigation on the OH*and CH* chemiluminescence characteristics of single coal particle flames under O2/CO2 atmosphere

Here, the OH* and CH* chemiluminescence characteristics of a single coal particle flame combustion in a visual drop-tube furnace (VDTF) for different oxygen fraction, Xi,O2, in O2/CO2 atmosphere were investigated using an optical diagnostic technique. The results indicate that the combustion of single coal particles is composed of a volatile reaction stage followed by a volatile-char reaction stage. During volatile reaction stage, the single coal particle burns in an enveloped flame. The flame becomes brighter and the flame length increases gradually. In addition, the OH* and CH* intensity shows peak values with axial distance along the furnace, with that of OH* appearing earlier as the oxygen fraction increases. In the volatile-char reaction stage, the flame length fluctuates slightly, and OH* and CH* peak position are spread over a smaller range of distance. The value of Xi,O2 affects the reaction rate as it promotes the diffusion of oxygen to the interior of coal particle, as the intensity of OH* and CH* increasing rapidly for Xi,O2 > 0.4. This indicates that the rate of reaction is controlled by Xi,O2. Furthermore, the peak intensity ratio of OH* and CH* increases linearly with Xi,O2.

High temperature surface graphitization of CVD diamond films and analysis of the kinetics mechanism

A plasma arc generator was used to heat treat the free-standing CVD diamond films at 1450–1900 °C. An Arrhenius curve was fit according to trends in the measured Raman peak intensity ratio of diamond to graphite as a function of heat treatment temperature, and the curve was extrapolated linearly. It was found that the extrapolation lines intersected at the Debye temperature, ΘD = 2021 K. By comparing the activation energies of diamond graphitization in literature and from different measurement modes in our study, it was found that the graphitization mechanisms were different on both sides of Debye temperature due to differences in the excited lattice vibration modes. When the heat treatment temperature was just below the Debye temperature, the graphitization process was promoted by generating vacancies or the breaking of single CC bonds, and the apparent activation energy was 366 ± 60 kJ·mol−1. When the heat treatment temperature was above the Debye temperature, the graphitization process was promoted by the simultaneous breaking of multiple CC bonds, and the apparent activation energy was 887 ± 141 kJ·mol−1. In combination with the morphology changes on the surface of the CVD diamond film after high temperature heat treatment, the mechanism of the micro-cyclic phase transition on the surface of the diamond film at temperatures lower than Debye temperature was summarized as follows. First, CC bonds on the diamond surface were activated and broken at high temperatures, and some diamond carbon atoms dissociated from solid phase sites to the gas phase by forming hydrocarbon free radicals. Then, the carbon atoms from these hydrocarbons entered the graphite lattice step by step to complete the spontaneous deposition of sp2 clusters.

Raman Spectral Shifts in Naturally Faulted Rocks

AbstractRaman spectral shifts of carbonaceous materials arising from faulted rocks produce varied and complex results. By analyzing faulted and adjacent non‐faulted samples from three discrete localities in France, Italy, and Morocco, we assess changes in specific Raman parameters, including G‐peak width, G‐peak position, and peak intensity ratios. We consistently observe a shift in Raman parameters between faulted and non‐faulted samples; however, the direction and magnitude of this shift varies. Raman peak intensity ratios are shown to both increase and decrease on fault planes. The majority of samples exhibit decreasing peak width and peak position in the faulted samples, but this is not consistent; in two samples an increase is observed, but the shift tends to be small. These data are compared to published Raman spectral shifts from experimental fault data. Our results suggest that fault zone deformation processes may measurably change the carbon nanostructure in faulted rocks. The inconsistent nature of Raman spectral shifts in the fault rock samples analyzed, and those published suggest that a complex set of factors control carbon nanostructure changes in fault rocks. These factors, although not discriminated here, likely include, background temperature, frictional heating, strain, carbonaceous material type, amongst others. We have shown that Raman Spectral shifts occur in faulted rocks with implications for how Raman data are used to predict maximum temperatures in faulted sedimentary rocks. We recognize the potential for a range of fault zone processes to modify Raman spectral shifts, however, systematic sampling across individual fault zones is critical.

Determination of asphaltene structural parameters by Raman spectroscopy

AbstractThe objective of this study is to determine the aromatic sheet diameter (La) and the number of aromatic sheets per stack (n) for asphaltene molecules from Raman spectra by investigating and optimizing empirical equations proposed in the literature for both crystalline and amorphous carbon materials. The results clearly indicated that the best empirical equation for determining the aromatic sheet diameter for asphaltene was the equation proposed by Tuinstra and Koenig, but only when the graphitization indicator ID/IG would have been determined from the peak integrated ratio, rather than from the peak intensity ratio. The best results of La were obtained when the Raman spectra were deconvoluted and fitted with three peaks using Gaussian function. The number of aromatic sheets per stack for asphaltene was also determined by examining various empirical equations proposed for crystalline carbon materials. The results indicated that these equations could be applied on asphaltene if the first‐order region of Raman spectrum were to be fitted with two peaks, representing the G and D bands. Fitting the spectra with more peaks could result in splitting the G band into two bands (i.e., G and D2 bands), which would shift the G‐band position to a wavenumber below 1581.6 cm−1, and, subsequently, prevent the utilization of these empirical equations.

Termal Olarak İndirgenen Grafen Oksidin Özelliklerinin İstatistiksel Analizi

In this study, the graphene oxide synthesized by the Hummers method was carried out using the thermal reduction under the vacuum and atmospheric pressure was carried out by the design of the Taguchi experiment. The thermal reduction under vacuum and atmospheric pressure has a higher ID/IG value (D peak intensity to G peak intensity ratio) at 36.84% and 42.31%, respectively, with respect to the chemical reduced oxide of the graphene oxide. If the chemical graphene oxide is thermally reduced under vacuum and atmospheric pressure, it has a higher ID/IG value, with 36.17% and 43.93%, respectively, with respect to the reduced graphene oxide. The thermal reduction under vacuum and atmospheric pressure has a higher carbon to oxygen ratio value (in other words higher reduction rate) at 72.19% and 74.58%, respectively, with respect to the chemical reduced oxide of the graphene oxide. If the chemical graphene oxide is thermally reduced under vacuum and atmospheric pressure, it has a higher carbon to oxygen ratio, with 74.56% and 78.92%, respectively, with respect to the reduced graphene oxide. The results showed that to obtain the highest reduction rate of graphene oxide; the thermal and H2 gas reduction process should be monitored under the atmospheric pressure of the chemically reduced graphene oxide.

Detection and quantitation of cellulose II by Raman spectroscopy

In cellulose materials, the cellulose II allomorph is often present either exclusively or in conjunction with cellulose I, the natural cellulose. Moreover, in regenerated and mercerized fibers (e,g., lyocell and viscose), natural cellulose adopts to the crystal structure cellulose II. Therefore, its detection and quantitation are important for a complete assessment of such materials investigations. In the Raman spectra of such materials, a band at 577 cm−1 is typically observed indicating the presence of this allomorph. In the present study, to quantify the content of cellulose II, a calibration method was developed based on the intensity of the 577 cm−1 peak relative to the 1096 cm−1 band of cellulose. For this purpose, in addition to pure cellulose I and cellulose II samples (respectively, Avicel PH-101 and mercerized Avicel PH-101; hence referred to as Avicel I and Avicel II), a set of five samples were produced by mixing them in known quantities of Avicel I and Avicel II. The crystalline cellulose II contents of the samples were calculated based on the X-ray crystallinity of mercerized Avicel I. These seven samples were included in the calibration set and their Raman spectra were obtained. Subsequently, Raman intensity ratios I577/I1096 were calculated by taking ratios of peak intensities at 577 and 1096 cm−1. These ratios were plotted against the % of crystalline cellulose II present in the calibration set samples and the two were found to be linearly correlated (R2 = 0.9944). The set-samples were also analyzed using XRD which were then compared with the Raman method developed here. Compared to XRD, the Raman method was found to be more sensitive at detecting and quantifying cellulose II. Additionally, several cellulose II containing materials were analyzed by the new Raman method. Graphic abstract

Intraoperative detection of human meningioma using a handheld visible resonance Raman analyzer.

To report for the first time the preliminary results for the evaluation of a VRR-LRR™ analyzer based on visible resonance Raman technique to identify human meningioma grades and margins intraoperatively. Unprocessed primary and recurrent solid human meningeal tissues were collected from 33 patients and underwent Raman analysis during surgeries. A total of 1180 VRR spectra were acquired from fresh solid tissues using a VRR-LRR™ analyzer. A confocal HR Evolution (HORIBA, France SAS) Raman system with 532-nm excitation wavelength was also used to collect data for part of the ex vivo samples after they were thawed from - 80°C for comparison. The preliminary analysis led to the following observations. (1) The intensity ratio of VRR peaks of protein to fatty acid (I2934/I2888) decreased with the increase of meningioma grade. (2) The ratio of VRR peaks of phosphorylated protein to amid I (I1588/I1639) decreased for the higher grade of meningioma. (3) Three RR vibration modes at 1378, 3174, and 3224cm-1 which were related to the molecular vibrational bands of oxy-hemeprotein, amide B, and amide A protein significantly changed in peak intensities in the two types of meningioma tissues compared to normal tissue. (4) The changes in the intensities of VRR modes of carotenoids at 1156 and 1524cm-1 were also found in the meningioma boundary. The VRR-LRR™ analyzer demonstrates a new approach for label-free, rapid, and objective identification of primary human meningioma in quasi-clinical settings. The accuracy for detecting meningioma tissues using support vector machines (SVMs) was over 70% based on Raman peaks of key biomolecules and up to 100% using principal component analysis (PCA).