Reliable estimation of Raman shifts for peaks of L-cystine (NMIJ CRM 6025-a) in the low-frequency region.

Raman scattered light is generated by the interaction of irradiated light with molecular vibrations, and it provides molecular information. Although Raman shifts of peaks in the low-frequency region (< 200 cm-1) provide useful information related to molecular structures, there are no reliable materials available for calibrating Raman spectrometers in this region. In this study, we chose high-purity L-cystine (NMIJ CRM 6025-a) and used it to reliably evaluate Raman shifts of peaks with uncertainty by a combination of HeNe laser and Ne emission lines. To evaluate their uncertainty, we considered the uncertainty originating from wavenumbers of Ne emission lines and HeNe laser, evaluation of wavenumber for peak-tops and changes in temperature. The obtained Raman shifts of eight peaks from 9 to 160 cm-1 and their uncertainty were 0.3 cm-1 or 0.4 cm-1 and these values were validated with the results using a 532 nm laser.

Development of a Polystyrene Reference Material for Raman Spectrometer (NMIJ RM 8158-a).

The Raman shift is one of the most important parameters in Raman spectroscopy, and is calculated from the difference in the wavenumbers for excitation and for Raman scattering. Because the observed shifts are strongly dependent on the spectrometer and the measurement conditions, physically and chemically stable reference materials for Raman-shift validation are required. We reliably estimated the Raman shift and evaluated its uncertainty for peaks of a 4-mm-thick, 25-mm-diameter polystyrene disc by using a HeNe laser and Raman-scattered light calibrated with Ne/Ar emission lines. We considered uncertainties originating from the fitting, repeatability, and reproducibility of both the Ne/Ar emission lines and the Rayleigh/Raman-scattered lights, as well as the wavenumber of the unstabilised HeNe laser, and pixel and spectral resolutions. We also considered uncertainty originating from inhomogeneity among and within discs, as well as their long-term stability. The obtained Raman shifts of 11 peaks (reference values) were comparable to those described in ASTM E1840 with expanded uncertainty at 1.1 or 1.2 cm-1 (k = 2, coverage factor).

Comparative evaluation of various low-level laser therapies on bone healing following tooth extraction: An experimental animal study.

PURPOSE: The aim of this study was to evaluate the effects of helium-neon and gallium-aluminum-arsenide lasers with various doses on bone healing following tooth extraction. MATERIALS AND METHODS: Maxillary right incisor teeth of 30 female albino Wistar rats were extracted. Five groups were established: four groups treated with helium-neon or gallium-aluminum-arsenide lasers and a control group. Both laser groups' rats received energy doses of 6 J/cm2 and 10 J/cm2 for 7 days. At the end of 30 days, all subjects were sacrificed for histological and morphological evaluations. RESULTS: Laser groups showed faster bone healing and gallium-aluminum-arsenide lasers increased vascular immunoreactivity. The most widespread organized bone formation in the extraction socket was observed in the gallium-aluminum-arsenide laser group with the energy dose of 10 J/cm2 (p < 0.05). CONCLUSION: This study demonstrated that low-level laser therapies were effective on alveolar bone healing and that an energy dose of 10 J/cm2 did not have an inhibition effect on bone regeneration.

Effect of Helium-Neon (HeNe) laser irradiacation on lesions in experimental paracoccidioidomycosis

Cutaneous lesions caused by the fungus Paracoccidioides brasiliensis lead to ulcerative wounds, which are difficult to be cured by conventional treatment with anti-fungal drugs due to their adverse effects and the multidrug resistance that some fungal isolates present. So, the laser therapy emerges as an alternative treatment since its anti-inflammatory effects and wound healing properties are already known. In this work, we showed that lesions caused by the inoculation of yeast cells into the back foot-pad of BALB/c mice and treated with HeNe laser present greater histologic organization, milder inflammatory infiltrate, higher organization of the granulation tissue around the lesion, and enhanced immunolabeling for iNOS. In addition, an increased SOD activity and NO concentration, higher percentage of macrophages, and lower neutrophil numbers were observed. The percentage of NK and NKT cells were also slightly higher after the first laser session. Altogether these results point towards a dual effect of the laser treatment, decreasing the inflammatory response and accelerating the wound healing of the lesions. In this sense, the HeNe laser can be considered as an effective adjunctive treatment to be combined with pharmacologic therapies for Effect of Helium-Neon (HeNe) laser irradiation on lesions in experimental paracoccidioidomycosis improving the treatment of painful non-healing paracoccidioidomycotic wounds.

Effect of low power laser on incisional wound healing.

INTRODUCTION: The effectiveness of low power lasers for incisional wound healing, because of conflicting results of previous research studies, is uncertain. Therefore, this study was carried out to evaluate low power laser effects on incisional wound healing. MATERIALS AND METHODS: Incisional wound was produced on thirty-six mature male guinea pigs under general and local anesthesia. In half of the cases, HeNe laser radiations were used for five minutes and the rest were left untreated Animals were divided into six groups of six animals each that were killed after 3, 5 and 14 days. After histopathology processing and H&E staining, specimens were examined for acute and chronic inflammations, epithelial cell migration, epithelial seal and barrier formation, fibroblast migration, fibrosis, clot formation and granulation tissue formation. Mann-Whitney U and the Wilcoxon tests were used for statistical analysis. RESULTS: Statistically significant differences were found between fibroblast migration, acute and chronic inflammation of radiated groups and the control group at 5 days interval (p<0.05). There was no statistically significant difference at 3 and 14 days between laser radiated and control groups. CONCLUSION: This study showed that HeNe laser had beneficial effects on incisional wound healing particularly at 5 days interval; however, further research on chronic ulcers is recommended.

Effects of HeNe laser irradiation on experimental paracoccidioidomycotic lesions

Paracoccidioidomycosis (PCM) is the most prevalent human mycosis in Latin America. The infection is thought to take place firstly in the lungs and then may disseminate to other organs and tissues. Treatment by currently available antifungals is lengthy, the drugs may have undesirable side effects, and some are costly. Occasional resistant strains of Paracoccidioides brasiliensis, the causative agent of PCM, have been reported. So, the search for more efficient treatments or adjuvant therapies has to be continued. In this work, we evaluated the effects of HeNe laser irradiation on cutaneous inflammatory lesions caused by the inoculation of 5 x 10(6)/0.1ml yeasts cells into the back footpad of Balb/c mice. HeNe irradiation (lambda=632.8nm, 3mW, incident energy of 3J/cm(2)) was applied at days 7, 8 and 9 post-infection and histological and immunohistochemical analysis were done. Unirradiated animals were used as controls. The results showed that laser-treated mice presented reduction of footpad edema, faster cutaneous wound healing, confluent granuloma, diffuse- and more loosely distributed immunolabeling for TNF-alpha, enhanced labeling of IFN-gamma and any P. brasiliensis form detected, whereas multiple viable fungi were seen in diffuse widespread granulomas obtained from non-treated mice foot-pad. Fungi that were harvested from laser-treated animals presented no capability of growth in vitro as compared to those obtained from non-treated mice. We conclude that HeNe laser irradiation was able to inhibit the progress of inflammatory local reaction produced by P. brasiliensis infection and influence local cytokines production. We suggest that this treatment modality can be a useful coadjuvant tool to be combined with antifungal agents in the treatment of PCM ulcerations. The mechanisms involved in laser therapy of PCM lesions need further investigation.