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Lubricating oils are essential in vehicles motors, and there are currently three variations in oil types: mineral, semisynthetic and synthetic. This work aimed to evaluate the degradation of these three types, by heating them in the laboratory between 120 to 150 oC for 48h, and subsequently evaluating their change in the composition through Raman spectroscopy. It was possible to observe compounds in common between the mineral and semi-synthetic oils in the peaks at 1002, 1380 and 1621 cm-1, and between the semi-synthetic and synthetic in the peak at 892 cm-1. In the evaluation of samples after heating, trough principal component analysis (PCA) technique, it was observed a decrease in the intensity of some peaks, suggesting molecular breakdown, as well as an increase in the intensity of other peaks suggesting formation of amorphous carbon. It was found a high correlation through heating time and peak intensity, by adjusting 2nd order polynomial curves, R² ranging from 0.96 to 0.99.

The repair of bone tissue is complex and can be influenced by several local and systemic factors that can delay the repair. Laser and LED phototherapies have shown positive results in the repair of bone tissue. The aim of this study was to evaluate, through Raman spectroscopy, the influence of laser (λ780 nm) and LED (λ850 nm) phototherapies in the repair of surgical defects in femurs of euthyroid and hypothyroid rats. Thirty Albinus Wistar rats were randomly divided into 6 groups. The animals of the hypothyroid groups were submitted to surgical removal of the thyroid gland. After general anesthesia, a surgical bone defect was created in the femur of each animal and filled with blood clot in all groups. In group I (Euthyroid) the defect was created in euthyroid animals; In Group II (Hypo) the defect was created in hypothyroid animals; In Group III (Euthyroid Laser) the defect was irradiated with Laser; on Group IV (Hypo Laser) the defect was made in a hypothyroid animal and irradiated with Laser; on Group V (Euthyroid LED) the defect was irradiated with LED and on Group VI (Hypo LED) the defect was created in hypothyroid animals and LED irradiated. Irradiation was carried out at every 48-h for 15 days. Specimens were taken and stored in liquid nitrogen. Intensity of peaks of phosphate HA (~960 cm-1), carbonated HA (~1,070 cm-1) and collagen (~1,414 cm-1) were measured by Raman Spectroscopy. The results showed that the health status had significant influence all peaks. Irradiation influenced only the peak of ~1454 cm-1. It is concluded that phototherapies influences bone repair in cases of thyroid diseases.

The aim of the present study was to assess, by means of Raman spectroscopy, the repair of complete surgical tibial fractures fixed with wire osteosynthesis or miniplates treated or not with infrared laser (λ780 nm) or infrared LED (λ850 ± 10 nm) lights, 142.8 J/cm2 per treatment, associated or not to the use of mineral trioxide aggregate (MTA) cement. Surgical fractures were created on 36 rabbits and fixed with WO or miniplates and some groups were grafted with MTA. Irradiated groups received lights at every other day for 15 days and sacrifice occurred after 30 days. The results showed that only irradiation with either laser or LED influenced the peaks of phosphate (~960 cm-1) and carbonated (~1,070 cm-1) hydroxyapatite. Collagen peak (1,450 cm-1) was influenced by both the use of MTA and irradiation with either laser or LED. It is concluded that the use of either laser or LED phototherapy associated to MTA cement was efficacious on improving the repair of complete tibial fractures treated with wire osteosynthesis or miniplates.

This work aimed the assessment of biochemical changes induced by laser or LED irradiation during mineralization of a bone defect in an animal model using a spectral model based on Raman spectroscopy. Six groups were studied: clot, laser (λ = 780 nm; 70 mW), LED (λ = 850 ± 10 nm; 150 mW), biomaterial (biphasic synthetic micro-granular hydroxyapatite (HA) + β-tricalcium phosphate), biomaterial + laser, and biomaterial + LED. When indicated, defects were further irradiated at a 48-h interval during 2 weeks (20 J/cm2 per session). At the 15th and 30th days, femurs were dissected and spectra of the defects were collected. Raman spectra were submitted to a model to estimate the relative amount of collagen, phosphate HA, and carbonate HA by using the spectra of pure collagen and biomaterials composed of phosphate and carbonate HA, respectively. The use of the biomaterial associated to phototherapy did not change the collagen formation at both 15 and 30 days. The amount of carbonate HA was not different in all groups at the 15th day. However, at the 30th day, there was a significant difference (ANOVA, p = 0.01), with lower carbonate HA for the group biomaterial + LED compared to biomaterial (p < 0.05). The phosphate HA was higher in the groups that received biomaterial grafts at the 15th day compared to clot (significant for the biomaterial; p < 0.01). At the 30th day, the phosphate HA was higher for the group biomaterial + laser, while this was lower for all the other groups. These results indicated that the use of laser phototherapy improved the repair of bone defects grafted with the biomaterial by increasing the deposition of phosphate HA.

Diabetes mellitus (DM) and arterial hypertension (AH) are common diseases that, if untreated, predispose the patient to renal failure. This study aimed to evaluate possible biomarkers in the urine of patients with DM and AH capable to predict the chronic renal disease, by means of Raman spectroscopy. Urines were obtained from patients with DM and AH, and separated into four groups: no symptoms of diseases related to DM and AH (G1), with low clinical complications (G2), with severe clinical complications (G3), and with chronic kidney disease (G4) arised from DM and AH. It has been used a dispersive Raman spectrometer (830nm, 250mW, 20s accumulation). In the spectra of urine it was identified Raman peaks at 680cm-1 (creatinine), 1004cm-1 (urea) and 1128cm-1 (glucose). The results revealed that G2, G3 and G4 presented the creatinine peak with lower intensity than G1 (p < 0.05). It was observed that G2, G3 and G4 showed lower intensity of the urea peak compared to G1 (p < 0.05) and G4 showed lower intensity compared to G2 and G3 (p < 0.05). Despite not significant, the glucose peak showed lower intensity in G1 when compared to the other groups. A model for classification of groups according to clinical criteria, using Sparse Multinomial Logistic Regression, taking as inputs the intensities of creatine, urea and glucose peaks allowed correct classification of 88.9% for G1, 36.8% for G2, 43.8% for G3 and 84.2% for G4. These results demonstrated the possibility of obtaining diagnostic information for complications of kidney disease associated to DM and AH, particularly the renal failure.

The use of insect repellents either indoors or at places with incidence of solar radiation has been common due to dengue epidemics in Brazil. The lack of studies on the photostability of these substances has motivated this study, where the main goal was to verify the photostability and photodegradation of some of the commercially insect repellents available under the simulated ultraviolet (UV) radiation, by evaluating the molecular changes using dispersive Raman spectroscopy (830 nm excitation). A laboratory-made chamber was used for irradiating the repellents, where UV-A + UV-B radiations (UV-A: 5.5 mW/cm 2 and UV-B 1.5 mW/cm 2 ) can be obtained. The chamber internal temperature did not exceed 31 °C during experiments. The compounds n,n-diethyl-m-toluamide (DEET), IR-3535, andiroba and citronella oils, used as active ingredients in insect repellents, and commercial formula containing DEET (14.5% in ethanol and isopropyl myristate) and IR-3535 (16% in carbopol) were continuously irradiated for 8 h. The Raman spectrum of each sample was obtained before and after UV exposure. The compounds and the commercial formula containing IR-3535 showed photo-stability when irradiated, since no changes in the peaks were found. The commercial formula containing DEET showed spectral decrease at 524, 690, 1003 and 1606 cm -1 , assigned to the DEET, and increase at 884 cm -1 , assigned to the ethanol. These results indicate that the excipient could influence the photostability of the active ingredient. The Raman spectroscopy can be suitable to monitor the photodegradation under UV irradiation rapidly and reliably.

Phototherapies have shown positive effects on the bone repair process, increasing the blood supply to the injured area. The aim of this study was to assess through Raman spectroscopy, the efficacy of laser phototherapy (λ = 780 nm, P = 70 mW, CW, 20.4 J/cm 2 per session, 163.2 J/cm 2 per treatment) on the bone repair process of osteoporotic rats. The osteoporosis induction was achieved by ovariectomy surgery. Thirty Wistar rats were divided into 4 groups (Basal; OVX, OVX + Clot and OVX + Clot + Laser), then subdivided into 2 subgroups according to the experimental time (15 and 30 days). After the osteoporosis induction time (60 days), a bone defect with 2 mm was created with a trephine drill in the right femur in the animals of groups OVX, Clot and Clot + Laser. After surgery, the irradiation protocol was applied in the same groups on repeated sessions every 48 hours during 15 days. The samples were analyzed by Raman Spectroscopy to assess the inorganic content of phosphate and carbonated hydroxyapatite (~960 and 1070 cm -1 , respectively) and organic lipids and proteins (~1454 cm -1 ). Statistical analysis (ANOVA, Student-T test) showed significant difference between groups Basal, OVX + Clot, and OVX + Clot + Laser for the inorganic content peaks at ~960 (p≤0.001), and ~1070 cm -1 (p≤0.001) in both periods of 15 and 30 days, however on peak at ~1450 cm −1 no differences were detected. It was concluded that the Laser phototherapy increased deposition of HA on bone repair process of osteoporotic rats.

The liver is responsible for several basic functions in human body how the syntheses of the most main proteins and degradation process of toxins, drugs and alcohols. In present days, the viral hepatitis C is one of the highest causes of chronic hepatic illness worldwide, affecting around 3% of the world population. The liver biopsy is considered the gold standard for diagnosing hepatic fibrosis; however, the biopsies may be questioned because of potential sampling error, morbidity, possible mortality and relatively high costs. Spectroscopy techniques such as Raman spectroscopy have been used for diagnosis of human tissues, with favorable results. Raman spectroscopy has been employed to distinguish normal from hepatic lesions through spectral features mainly of proteins, nucleic acids and lipids. In this study, eleven patients with diagnoses of chronic hepatitis C underwent hepatic biopsies having two hepatic fragments collected: one was scored through METAVIR system and the other one was submitted to near-infrared Raman spectroscopy using a dispersive spectrometer (830 nm wavelength, 300 mW laser power and 20 s exposure time). Five spectra were collected in each fragment and submitted to Principal Components Analysis (PCA). Results showed a good correlation between the Raman spectroscopy features and the stage of hepatic fibrosis and inflammation. PCA showed that samples with higher degree of fibrosis presented higher amount of protein features (collagen), whereas samples of higher degree of inflammation presented higher features of hemoglobin, in accordance to the expected evolution of the chronic hepatitis. It has been found an important biomarker for the beginning of hepatic lesion (quinone) with a spectral feature at 1595 cm -1 .

This work aimed the development of a discriminating model, using Raman spectroscopy, based on the estimated concentration of biochemical components presented in skin, for in vivo diagnosis. Raman spectra were collected in patients who underwent excision surgery of suspicious lesions at the lesion site and at a no rmal circumjacent site. It has been estimated the relative amount of selected biochemical compounds presented in skin. The Raman spectra of normal and malignant (basal cell carcinoma - BCC and squamous cell carcinoma - SCC) skin are quite similar, with some spectral differences in the regions of lipids, nucleic acids, and hemoglobin. Some biochemicals showed statistically significant differences among N, BCC and SCC, such as elastin, ceramide, melanin, nucleid acid, actin and phenylalanine. Elastin and ceramide presented significant differences between N and BCC, melanin, DNA and actin presented significant differences between N and BCC and be tween N and SCC, being melanin and DNA decreased in neoplasias, in contrast with actin, that increased in neoplasias. Concentration of phenylalanine was significantly increased for SCC compared to N and BCC. The relative concentration of melanin, DNA and phenylalanine showed sensitivity, specificity and accuracy of about 81%, 65% and 60%, respectively, using Mahalanobis distance as a discriminator. This model is being incorporated to a Raman system with automated data collection and processing that could be used for a future in vivo , real time discrimination algorithm. Keywords: Raman spectroscopy, basal cell carcinoma, squamous cell carcinoma, in vivo diagnosis, least-squares fitting

It has been proposed a spectral model to evaluate the biochemical differences between prostate carcinoma and benign fragments using dispersive Raman spectroscopy. We have examined 51 prostate fragments from surgically removed PrCa; each fragment was snap-frozen and stored (-80°C) prior spectral analysis. Raman spectrum was measured using a Raman spectrometer (830 nm excitation) coupled to a fiber-optic probe. Integration time and laser power were set to 50 s and 300 mW, respectively. It has been collected triplicate spectra from each fragment (total 153 spectra). Some samples exhibited a strong fluorescence, which was removed by a 7th order polynomial fitting. It has been developed a spectral model based on the least-squares fitting of the spectra of pure biochemicals (actin, collagen, elastin, carotene, glycogen, phosphatidylcholine, hemoglobin, and water) with the spectra of tissues, where the fitting parameters are the relative contribution of the compounds to the tissue spectrum. The spectra (600-1800 cm -1 range) are dominated by bands of proteins; it has been found a small difference in the mean spectra of PrCa compared to the benign tissue, mainly in the 1000-1400 cm -1 region, indicating similar biochemical constitution. The spectral fitting model revealed that elastin and phosphatidylcholine were increased in PrCa, whereas blood and water were reduced in malignant lesions ( p < 0.05). A discrimination of PrCa from benign tissue using Mahalanobis distance applied to the contribution of elastin, hemoglobin and phosphatidylcholine resulted in sensitivity of 72% and specificity of 70%.

Benefits of the isolated or combined use light and biomaterials on bone healing have been suggested. Our group has used several models to assess the effects of laser on bone. A Raman spectral analysis on surgical bone defects grafted or not with Hydroxyapatite (HA), treated or not with LED was carried out. 40 rats were divided into 4 groups. On Group I the defect was filled with the clot. On Group II, the defect was filled with the HA. On groups III the defect was filled with Clot and further irradiated with LED and on group IV the defects was filled with the HA and further irradiated with LED. LED (λ850 ± 10nm, 150mW, A= 0.5cm2, 68s, 20 J/cm2 per session, 140 J/cm2 per treatment) was applied at 48 h intervals during 15 days. Specimens were taken after 15 and 30 days after surgery and kept on liquid nitrogen, and underwent Raman analysis. For this, the peak of hydroxyapatite (~960 cm-1) was used as marker of bone mineralization. Significant difference was observed at both times (p

Diabetes mellitus and hypertension diseases are frequently found in the same patient, which if untreated predispose to atherosclerotic and kidney diseases. The objective of this study was to identify potential biomarkers in the urine of diabetic and hypertensive patients through dispersive near-infrared Raman spectroscopy. Urine samples were collected from patients with diabetes and hypertension but no complications (LG), high degree of complications (HG), and control ones: one fraction was submitted to biochemical tests and an other one was stored frozen (-20oC) until spectral analysis. Samples were warmed up and placed in an aluminum samp le holder for Raman spectra collection using a dispersive spectrometer (830 nm wavelength, 300 mW laser power and 20 s exposure time). Spectra were then submitted to Principal Components Analysis. The PCA loading vectors 1 and 3 revealed spectral features of urea/creatinine and glucose, respectively; the PCA scores showed that patients with diabetes/hypertension (LG and HG) had higher amount of glucose in the urine compared to the normal group ( p < 0.05), which can bring serious consequences to patients. Also, the PCA scores showed that the amount of urea decreased in the groups with diabetes/hypertension (p < 0.05), which generates the same concern as it is a marker that has a strong importance in the metabolic changes induced by such diseases. These results, applied to the analysis of urine of patients with diabetes/hypertension, can lead to early diagnostic information of complications and a possible disease prognosis in the patients where no complications from diabetes and hypertension were found. Keywords: Raman spectroscopy, hypertension, diabetes mellitus, renal complications

We studied peaks of calcium hydroxyapatite - CHA on defects grafted with MTA, treated or not with Light Emitting Diode – LED or IR Laser. 54 rats were divided in 6 gr oups each subdivided into 3 subgroups (15,21,30d). LED ( O 850 ± 10nm) or IR Laser (O 850 nm) was applied over (LED) or in 4 points around the defect at 48 h intervals for 15 days. Raman readings were taken at the surface of the defect. The smaller overall intensity of the peak was found in Group MTA + Laser (1510.2 ± 274.1) and the highest on Group LED (2322 ± 715). There were no statistically significant differences between non-irradiated subjects on regards the CHA peaks. On the other hand, there were statistically significant differences between the Group Clot and LED, Clot and Laser, and Clot and MTA + Laser ( p =0.01, p = 0.02, p = 0.003). There were no significant differences between Group MTA and MTA + LED (p=0.2) but significant differences were seen between Groups MTA and MTA + Laser (p=0.01). Significant differences were also observed between Groups LED and Laser (p

This work demonstrated the discrimination among basal cell carcinoma (BCC) and normal human skin in vivo using near-infrared Raman spectroscopy. Spectra were obtained in the suspected lesion prior resectional surgery. After tissue withdrawn, biopsy fragments were submitted to histopathology. Spectra were also obtained in the adjacent, clinically normal skin. Raman spectra were measured using a Raman spectrometer (830 nm) with a fiber Raman probe. By comparing the mean spectra of BCC with the normal skin, it has been found important differences in the 800-1000 cm -1 and 1250-1350 cm -1 (vibrations of C-C and amide III, respectively, from lipids and proteins). A discrimination algorithm based on Principal Components Analysis and Mahalanobis distance (PCA/MD) could discriminate the spectra of both tissues with high sensitivity and specificity.

A method, based on Raman spectroscopy, for identification of different microorganisms involved in bacterial urinary tract infections has been proposed. Spectra were collected from different bacterial colonies (Gram-negative: Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa and Enterobacter cloacae, and Gram-positive: Staphylococcus aureus and Enterococcus spp.), grown on culture medium (agar), using a Raman spectrometer with a fiber Raman probe (830 nm). Colonies were scraped from the agar surface and placed on an aluminum foil for Raman measurements. After preprocessing, spectra were submitted to a principal component analysis and Mahalanobis distance (PCA/MD) discrimination algorithm. We found that the mean Raman spectra of different bacterial species show similar bands, and S. aureus was well characterized by strong bands related to carotenoids. PCA/MD could discriminate Gram-positive bacteria with sensitivity and specificity of 100% and Gram-negative bacteria with sensitivity ranging from 58 to 88% and specificity ranging from 87% to 99%.

This work evaluated possible alterations in the Raman spectra of human prostate tissues in vitro, by developing a Principal Components Analysis algorithm for discriminating prostate carcinoma (PrCa) and benign prostate tissue. Raman spectrum was measured using a Raman spectrometer (830 nm) with a fiber Raman probe. Most of the samples exhibited a very strong background fluorescence, which was decreased by photobleaching the fragment during 5 min. and the remaining fluorescence was removed by polynomial filtering. The spectra of prostate in the fingerprint region are dominated by bands of proteins (mainly collagen, elastin, actin). By comparing the spectra of PrCa with the benign prostate tissue, we found a very small difference, indicating similar biochemical constitution of benign and malignant prostate tissue. Principal Components Analysis and Mahalanobis distance could discriminate the spectra of both benign and PrCa tissues with reasonable sensitivity and specificity.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

This work proposes the evaluation of the macronutrient constitution of human breast milk based on the spectral information provided by near-infrared Raman spectroscopy. Human breast milk (5 mL) from a subject was collected during the first two weeks of breastfeeding and stocked in -20oC freezer. Raman spectra were measured using a Raman spectrometer (830 nm excitation) coupled to a fiber based Raman probe. Spectra of human milk were dominated by bands of proteins, lipids and carbohydrates in the 600-1800 cm -1 spectral region. Raman spectroscopy revealed differences in the biochemical constitution of human milk depe nding on the time of breastfeeding startup. This technique could be employed to develop a classification routine for the milk in Human Milk Banking (HMB) depending on the nutritional facts. Keywords: near-infrared Raman spectroscopy, human milk, macronutrients, quantification 1. INTRODUCTION Milk is the first food ingested by mammals. Human milk is considered the most complete and balanced composition of macro and micronutrients for the infant’s diet, containing more than 250 components which are present in proportion and chemical form that are characteristics for the humans

The aim of this study was to evaluate, through Raman spectroscopy, the repair of complete tibial fracture in rabbits fixed with wire osteosynthesis - WO, treated or not with infrared laser light (λ 780nm, 50mW, CW) associated or not to the use of HATCP and GBR. Surgical fractures were created under general anesthesia (Ketamine 0.4ml/Kg IP and Xilazine 0.2ml/Kg IP), on the tibia of 15 rabbits that were divided into 5 groups and maintained on individual cages, at day/night cycle, fed with solid laboratory pelted diet and had water ad libidum. On groups II, III, IV and V the fracture was fixed with WO. Animals of groups III and V were grafted with hydroxyapatite + GBR technique. Animals of groups IV and V were irradiated at every other day during two weeks (16J/cm2, 4 x 4J/cm2). Observation time was that of 30 days. After animal death the specimens were kept in liquid nitrogen for further analysis by Raman spectroscopy. Raman spectroscopy showed significant differences between groups (p

Biomedical applications of near-infrared Raman spectroscopy have increased their importance at the last ten years. This technique can determinate the molecular composition of materials, allowing a sensible and fast biological diagnosis. It has showed to be a promising tool for health diagnosis due to its high sensibility. Colorectal cancer (CRC) is one of the most common malignant tumors in humans beings. In the last decades many experimental models have been developed in animals based in the use of chemical composites to induce the formation and development of these tumors, many of them present similar characteristics to those of natural occurrence aiming to the attainment of information on genesis, evolution, as well as diagnosis and more efficient therapies for treating these neoplasias. Amongst the most used chemical composites is the 1,2- dimetilhydrazine (DMH) because its morphological and histological similarity to those tumors. This study aims to compare in vivo normal colon tissue and tumoral colon tissue, induced by DMH, in rats by near-infrared Raman spectroscopy to permit the use in the near future for an efficient diagnosis in real time besides being useful as an auxiliary method for several therapies, including the photodynamic therapy.

Several studies have identified the degree of aortic valve calcification as a strong predictor both for the progression and outcome of aortic stenosis. In industrialized countries, aortic valve stenosis is most frequently caused by progressive calcification and degeneration of aortic cusps. However, there are no accurate methods to quantify the extent of aortic valve calcification. To provide a non-invasive alternative to biopsy, a range of optical methods have been investigated, including Raman and reflectance spectroscopy. A Raman spectrum can be used to access the molecular constitution of a particular tissue and classify it. Raman spectroscopy is largely used in the quantification and evaluation of human atherosclerosis, being a powerful technique for performing biochemical analysis without tissue removal. Nevertheless, increased thickness and disorganization of the collagen fibre network and extracellular matrix are known to affect the diffuse spectral reflectance of the tissue. A catheter with the "6 around 1" configuration, the central fiber transmit laser radiation to the sample and the scattered light is collected by the other six surrounding fibers, was used both for Raman and reflectance spectroscopy. A white light (krypton lamp, flashtube Model FX 1160 Perkin Elmer, USA) excitation was used for reflectance measurements. A Ti-sapphire (785nm, Spectra Physics, model 3900S, USA) laser, pumped by an argon laser (Spectra Physics, model Stabilite 2017, USA) was used as the near infrared Raman set up. Several ex-vivo spectra of aortic valve samples were analyzed. The results show a promising way to differentiate normal, fibrous and calcified tissue in aortic valve.

FT- Raman Spectroscopy (FT-Raman) could allow identification and evaluation of human atherosclerotic lesions. A Raman spectrum can provide biochemical information of arteries which can help identifying the disease status and evolution. In this study, it is shown the results of FT-Raman for identification of human carotid arteries in vitro. Fragments of human carotid arteries were analyzed using a FT-Raman spectrometer with a Nd:YAG laser at 1064nm operating at an excitation power of 300mW. Spectra were obtained with 250 scans and spectral resolution of 4 cm-1. Each collection time was approximately 8 min. A total of 75 carotid fragments were spectroscopically scanned and FT-Raman results were compared with histopathology. Principal Components Analysis (PCA) was used to model an algorithm for tissue classification into three categories: normal, atherosclerotic plaque without calcification and atherosclerotic plaque with calcification. Non-atherosclerotic (normal) artery, atherosclerotic plaque and calcified plaque exhibit different spectral signatures related to biochemicals presented in each tissue type, such as, bands of collagen and elastin (proteins), cholesterol and its esters and calcium hydroxyapatite and carbonate apatite respectively. Results show that there is 96% match between classifications based on PCA algorithm and histopathology. The diagnostic applied over all 75 samples had sensitivity and specificity of about 89% and 100%, respectively, for atherosclerotic plaque and 100% and 98% for calcified plaque.

FT-Raman spectroscopy is a modern analytical tool and it is believed that its use for skin cancer diagnosis will lead to several advantages for patients, e.g., faster results and a minimization of invasivity. This article reports results of an ex Vivo study of the FT-Raman spectra regarding differentiation between non-diseased and malignant human skin lesions, Basal Cell Carcinoma (BCC). A Nd: YAG laser at 1064nm was used as the excitation source in the FT-Raman, RFS 100/S Spectrometer, Bruker. Thirty-nine sets of human skin samples, 18 histopathologically diagnosed as non-diseased, and 21 as BCC, were obtained during routine therapeutic pr ocedures required by the primary disease. No sample preparation was needed to promote the FT-Raman spectra collection. The main spectral features, which may differentiate the sample, were found in the shift region of Amide I (1640 to 1680 cm -1) , Amide III (1220 to 1330cm -1 ), proteins and lipids (1400 to 1500 cm -1 ), amino acids (939 to 940 cm -1) and deoxyribonucleic acid (1600 to 1620cm –1) . Principal Components Analysis (PCA) was applied to FT-Raman spectra of Basal Cell Carcinoma. Analysis was performed on mean-normalized and mean-centered data of the non-diseased skin and BCC spectra. The dynamic loading of PCA was expanded into 2D contour by calculating a variance-covariance matrix. PCA was used to verify the statistical differences in the sample. This technique applied over all samples identified tissue type within 83% of sensitivity and 100% specificity. The PCA technique proved efficient for analysis in skin tissue ex vivo, results were significant and coherent.

FT-Raman Spectroscopy (FTRS) has being applied as a new diagnostic tool for the early detection of oral cancer, showing spectral sensitivity to changes in the molecular composition and morphology associated with malignant tissues. A carcinogen (7, 12 – dimethybenz[a]anthracene - DMBA) was applied daily in the buccal pouch of 23 hamster and after 14 days fragments of chemically-induced and normal tissue were analyzed by FTRS. A 1064nm, 100mW Nd:YAG laser was used as excitation source. A total of 123 spectra were obtained (three in each site, left and right pouch). They were divi ded into normal and malignant tissue groups according to the anatomopathologist and were analyzed statistically based on Principal Components Analysis (PCA). The spectra region of 1263 - 1337 cm -1 showed significant difference between the normal and squamous cell carcinomas samples. The region of 1555 – 1560 cm -1 also has showed an increase of intensity in the malignant samples. An algorithm based on Principal Components Analysis could separate the samples in two groups, obtaining 86% of sensitivity and 93% of specificity, for the training group, while the prospective group had 85% of sensitivity and 88 % of specificity. Results suggest that the FT-Raman spectroscopy can be useful for detection of malign oral lesion in an animal model.

The primary objective of this work was to use FT-Raman spectroscopy to detect spectral changes between benign and basal cell carcinoma (BCC) skin tissues. Those spectral changes can give us important information about the biochemical alterations between these two types of tissues. The early cancer detection stills a great challenge in clinical oncology. Recently, Raman spectroscopy has been used for skin lesion detection. FT-Raman spectroscopy is a modern analytical tool and its use for cancer diagnosis will lead to several advantages for the patient as, for example, real time and less invasive diagnosis. We have analyzed by FT-Raman eight sets of samples histopathologically diagnosed as BCC and made a comparison with five sets of samples diagnosed as benign tissue. We have found that the main spectral differences between these samples were in the shift region of 1220-1300cm-1 and 1640-1680cm-1. These vibration bands correspond to the amide III and to the amide I vibrations, respectively. Principal component analysis applied over all 13 samples could identify tissue type with 100% of sensitivity and specificity.

Comparative studies were carried out on the Al- phthalocyanine and Zn-phthalocyanine uptake in iliac artery wall of rabbit, through transadventitial fluorescence measurements. Two 3.5 Kg Norfolk make rabbit were used. The iliac artery was dissected, isolated and clamped at two points, 1.5 cm apart. The experiment comprised three steps, collecting fluorescence spectra at several point inside and outside of the clamped region of the artery. The excitation source was a 488 nm Argon Laser. Firstly, it was measured the pre and post clamping transadventitial fluorescence without the photosensitizer. After that, 50 (mu) L of AlPc or ZnPc solutions in Cremiphor EL, 2.5 (mu) M, were injected locally into the artery clamped region of each rabbit and fluorescence spectra were collected at t equals 0 and 15 min. Finally, elapsed 30 min. Temporal evolution of the drug uptake by the artery wall was studied analyzing the intensities of the fluorescence peaks at 682 and 678 nm for AlPc and ZnPc, respectively. It was found that AlPc is more absorbed and remains for a longer time in the iliac artery wall than the ZnPc.

A growing number of studies have demonstrated that autofluorescence and induced fluorescence spectroscopy can be used to distinguish normal and abnormal tissues in vivo. Through photochemical accumulation in atherosclerotic lesions it is possible to obtain induced fluorescence, this accumulation has been demonstrated in many researches. The aim of this study was to diagnose, by aluminum phthalocyanine transadventitial fluorescence, atherosclerotic plaques in artery wall of rabbits. Five male Norfolk rabbits were submitted to a high level cholesterol diet for 9 weeks. When the blood cholesterol level reached around 1000 mg/dl three of these animals were injected intravenously 50(M/50(l of aluminum phthalocyanine (AlPc). After 24 hours these animals were submitted to a surgery to expose the iliac artery. The transadventitial fluorescence spectra were acquired in several points over the artery. Characteristic peaks of the collagen, the porphyrin and the induced by AlPc were observed.

The aim of this work was to verify the Al-Phthalocyanine (AlPc) absorption in iliac artery wall of a rabbit, through transadventitial fluorescence measurement. Two Norfolk male rabbits, weighing 3.5 kg were used. The iliac artery was dissected and isolated. The artery was then clamped in two points with simple ligatures spaced 1.5 cm. The experiment was made in three phases, with acquisition of several fluorescence spectra in different points of the iliac artery. Firstly was measured the pre and post clamping transadventitial fluorescence without the presence of the photosensitizer. On the second phase, the AlPc, 2.5 (mu) M in 50 (mu) L solution, was injected locally into the clamped region and fluorescence spectra were collected in t=0 minutes and t=15 minutes. Finally, 30 minutes from the beginning of the experiment the clamping was removed, the blood flow restarted into the artery, and the fluorescence spectra was collected in t=5 minutes and t=10 minutes. The excitation was made using an Argon Laser (Stabilite 2017-Spectra Physics), operating in 488nm with 7mW optical power measured at the distal fiber tip. A unique peak, centered in 682nm, identifies the AlPc presence on the analyzed tissue.

We have designed, fabricated and tested a compact excitation-emission spectrofluorimeter with optical fiber light delivery and collection for use in rapid analysis of tissues in a clinical setting. This system provides ten different excitation wavelengths, permitting collection of all ten emission spectra from biological tissues in approximately 500 ms. It uses a nitrogen laser which pumps a sequence of dyes placed in cuvettes on a rotating wheel. All dye cuvettes utilize a common optical resonant cavity, which simplifies the coupling of the different excitation wavelengths into the delivery fiber of an optical fiber probe. A filter wheel containing one long-pass filter for each excitation wavelength is synchronized with the dye wheel for compactness and ease of control. A white light excitation source permits acquisition of the tissue diffuse reflectance spectrum on each cycle. The fiber optic probe is composed of seven optical fibers arranged at the distal tip in the form of a central delivery fiber surrounded by six collection fibers, with an optical shield. Return fluorescence and reflected light are dispersed by a small spectrograph and detected by a photodiode array detector. The system can collect a single shot spectrum from biological tissue with a signal-to-noise ratio in excess of 50:1. This unique design for providing rapidly variable excitation wavelengths facilitates the collection of multi- excitation fluorescence spectra for the diagnosis of diseases in vivo.

This experiment presents the characterization of a medium birefringence single mode optical fiber within a composite, when submitted to radial strength. The system operation is based on elasto-optic effect, which induces birefringence in the optical fiber, modifying the polarization state of the guided light. The changes in the polarization state of the signal are converted into intensity variations and are detected by a silicon photodiode and analyzed using a microcomputer.

In this work we describe an optical sensor to determine the stress applied at a concrete structure. The optical sensor is a monomode fiber optic, that is embedded in the concrete. The principle of these sensors is based on photoelastic effect, that produces a birefringence in the optical fiber and induces a rotation on the polarization angle of the guided polarized light. The photoelastic effect is produced due to a controlled applied charge in the center of the concrete structure. The shift of polarization is analyzed by a polaroid analyzer.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.