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Selected AbstractsMorphology, chemical structure and diffusion processes of root surface after Er:YAG and Nd:YAG laser irradiationJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 6 2001B. Ga Abstract Objectives: The aim of this in vitro study was to evaluate the effects of Er:YAG and Nd:YAG lasers on morphology, chemical structure and diffusion processes of the root surface. Material and methods: 60 root samples were irradiated for 1 min each either with 60 mJ/p, 80mJ/p and 100mJ/p using Er:YAG laser or with 0.5W, 1.0W and 1.5W using Nd:YAG laser. Scanning electron microscopy (SEM) was used to determine the morphology, infrared (IR) spectroscopy to assess the alterations in chemical structure and one dimensional electron paramagnetic resonance imaging (1-D EPRI) was used to estimate the diffusion coefficients in dental root samples. Results: Er:YAG laser treatment resulted in deep crater formation with exposed dentin. Morphological alterations of root surface after Nd:YAG laser irradiation included cracks, crater formation, meltdown of the root mineral and resolidified porous globules formation. Er:YAG laser failed to alter the intensity of Amide peaks I, II or III. In contrast, treatment with Nd:YAG laser, using the highest power setting of 1.5W, reduced the intensity of Amide peak II and III in comparison to the control. The diffusion coefficients were increased significantly in all Er:YAG and Nd:YAG treated root samples. Conclusion: This study demonstrated that Er:YAG laser influences only on morphology and diffusion processes of root surfaces, while Nd:YAG laser also alters the chemical structure of root proteins. Zusammenfassung Ziele: Das Ziel dieser in vitro Studie war es, die Wirkung von Er:YAG- und Nd:YAG-Laser auf die Morphologie, chemische Struktur und die Diffusionsprozesse zu evaluieren. Material und Methoden: 60 Proben von Wurzeln wurden für eine Minute entweder mit einem Er:YAG-Laser und 60 mJ/p, 80 mJ/p und 100 mJ/p oder einem Nd:YAGLaser und 0.5 W, 1.0 W und 1.5 W bestrahlt. Die Rasterelektronenmikroskopie (REM) wurde verwendet um die Morphologie zu bestimmen, Infrarotspektroskopie (IR) zur Messung der Veränderung in der chemischen Struktur und die eindimensionale paramagnetische Elektronenresonanz-Bildgebung (1-D EPRI) wurde verwendet um die Diffusions-Koeffizienten in den dentalen Wurzelproben abzuschätzen. Ergebnisse: Die Behandlung mit dem Er: YAG-Laser resultierte in der Ausbildung tiefer Krater mit exponiertem Dentin. Die morphologischen Veränderungen der Wurzeloberfläche nach Bestrahlung mit dem Nd: YAG-Laser waren Brüche, Kraterbildung, Aufschmelzen des Wurzelminerals und Bildung wiederverfestigter poröser Globuli. Mit dem Er:YAG-Laser gelang es nicht die Intensität der Amid-peaks I, II oder III zu verändern. Im Gegensatz dazu reduzierte die Behandlung mit dem Nd:YAG-Laser im Vergleich mit der Kontrolle bei der höchsten Leistungseinstellung von 1.5 W die Intensität der Amid-Peaks II und III. In allen mit Er: YAG und Nd:YAG behandelten Wurzelproben waren die Wurzeldiffusionskoeffizienten signifikant erhöht. Schlussfolgerung: Diese Studie demonstrierte, dass der Er:YAG-Laser nur die Morphologie und die Diffusionsprozesse der Wurzeloberfläche beeinflusst, während der Nd: YAG-Laser auch die chemische Struktur der Wurzelproteine verändert. Résumé Morphologie, structure chimique et processus de diffusion de surfaces radiculaires après irradiation au lasers Er:YAG et Nd:YAG But: Le but de cette étude in vitro était d'évaluer les effets des lasers Er:YAG et Nd:YAG sur la morphologie, la structure chimique et les processus de diffusion des surfaces radiculaires. Matériaux et méthodes: 60 échantillons de racines furent irradiés pendant 1 min chacun par 60 mJ/p, 80 mJ/p et 100 mJ/p avec le laser Er:YAG ou par 0.5 W, 1.0 W et 1.5 W avec le laser Nd:YAG. La microscopie électronique à balayage (SEM) a été utilisée pour déterminer la morphologie, la spectroscopie infra rouge pour mettre en évidence les altérations de la structure chimique et l'imagerie en une dimension par résonnance magnétique électronique (1-DEPRI) fut utilisée pour estimer les coefficients de diffusion dans les échantillons de racines dentaires. Résultats: Le traitement au laser Er:YAG entrainait la formation de cratères profonds avec de la detine exposée. Les altérations morphologiques de la surface radiculaire après irradiation au laser Nd:YAG prenaient la forme de félures, de cratères, fusion du minéral radiculaire et formation de globules poreux resolidifiés. Le laser Er:YAG n'arrivait pas à altérer l'intensité des pics Amide I, II our III. Au contraire, le traitement au laser Nd:YAG, en utilisant la plus haute puissance de 1.5 W, réduisait l'intensité des pics Amide II et III, par rapport au contrôle. Les coefficients de diffusion étaient significativement augmentés pour toutes les racines traitées par les lasers Er:YAG et Nd:YAG. Conclusions: Cette étude démontre que le laser Er:YAG a une influence sur seulement la morphologie et les processus de diffusion des surfaces radiculaires alors que le laser Nd:YAG modifie également la structure chinique des protéines radiculaires. [source] In vitro evaluation of Er:YAG laser scaling of subgingival calculus in comparison with ultrasonic scalingJOURNAL OF PERIODONTAL RESEARCH, Issue 5 2000A. Aoki The purpose of the present study was to evaluate the effectiveness of Er:YAG laser scaling and the morphological and histological changes of the laser-scaled root surface in comparison with the effectiveness and root surface changes produced by conventional ultrasonic scaling. Fifty-three periodontally involved human extracted teeth with a band of subgingival calculus were used. The teeth were divided randomly into 2 groups for laser scaling and ultrasonic scaling. Laser irradiation was performed at an energy output of 40 mJ/pulse and 10 pulses/s under water spray, with the probe tip contacted obliquely to the root surface. Ultrasonic scaling was performed at a clinically standard power setting. The time required for scaling, the scaled area and the temperature changes were determined using both methods of treatment. The features of the scaled surfaces were examined by histological and scanning electron microscope (s.e.m.) observations. The Er:YAG laser provided subgingival calculus removal on a level equivalent to that provided by the ultrasonic scaler, without major thermal elevation. Macroscopically, the laser-treated root surface was somewhat rougher than or similar to the ultrasonically scaled root. However, the efficiency of the laser scaling was lower than that of the ultrasonic scaling. In addition, histological examination revealed a thin deeply stained zone on the lased root surface, and s.e.m. analysis revealed a characteristic microroughness on the lased surface. The laser scaling provided a level of calculus removal that was similar to that provided by the ultrasonic scaling. However, the Er:YAG laser produced superficial, structural and thermal microchanges on the root cementum. [source] Laser-induced phase changes in olivine FePO4: a warning on characterizing LiFePO4 -based cathodes with Raman spectroscopyJOURNAL OF RAMAN SPECTROSCOPY, Issue 2 2009Christopher M. Burba Abstract Raman spectroscopy is an excellent technique for probing lithium intercalation reactions of many diverse lithium ion battery electrode materials. The technique is especially useful for probing LiFePO4 -based cathodes because the intramolecular vibrational modes of the PO43, anions yield intense bands in the Raman spectrum, which are sensitive to the presence of Li+ ions. However, the high power lasers typically used in Raman spectroscopy can induce phase transitions in solid-state materials. These phase transitions may appear as changes in the spectroscopic data and could lead to erroneous conclusions concerning the delithiation mechanism of LiFePO4. Therefore, we examine the effect of exposing olivine FePO4 to a range of power settings of a 532-nm laser. Laser power settings higher than 1.3 W/mm2 are sufficient to destroy the FePO4 crystal structure and result in the formation of disordered FePO4. After the laser is turned off, the amorphous FePO4 compound crystallizes in the electrochemically inactive ,-FePO4 phase. The present experimental results strongly suggest that the power setting of the excitation laser should be carefully controlled when using Raman spectroscopy to characterize fundamental lithium ion intercalation processes of olivine materials. In addition, Raman spectra of the amorphous intermediate might provide insight into the ,-FePO4 to olivine FePO4 phase transition that is known to occur at temperatures higher than 450 °C. Copyright © 2008 John Wiley & Sons, Ltd. [source] INLINE RADIOFREQUENCY ABLATION-ASSISTED LAPAROSCOPIC LIVER RESECTION: FIRST EXPERIMENT WITH STAPLING DEVICEANZ JOURNAL OF SURGERY, Issue 6 2007Peng Yao Background: In liver surgery, the increase in advancement of laparoscopic equipment has allowed the feasibility and safety of complex laparoscopic liver resection. However, blood loss and the potential risk of gas embolism seem to be the main obstacles. In this study, we successfully used the InLine radiofrquency ablation (RFA) device to carry out laparoscopic hand-assisted liver resection in pigs. Methods: Under general anaesthesia with tracheal intubation, pigs underwent InLine RFA-assisted laparoscopic liver resection. After installation of Hand Port and trocars, the InLine RFA device was introduced through Hand Port system and inserted into the premarked resection line. Then the generator was turned on and the power was applied according to the power setting. The resection was finally carried out using diathermy or stapler. For the control group, resection was simply carried out by diathermy or stapler. Results: Eight Landrace pigs underwent 23 liver resections. Blood loss was reduced significantly in the InLine group (P < 0.001) when compared with control group in both surgical methods (diathermy and stapler). Conclusion: In this study, we successfully carried out InLine RFA-assisted laparoscopic liver resection in both stapled and diathermy group. We showed that there was a highly significant difference between InLine and other liver resection techniques laparoscopically. [source] Exposure of non-target tissues in medical diathermyBIOELECTROMAGNETICS, Issue 1 2010N. Leitgeb Abstract With different prevalence in different regions, radio frequency (RF) electromagnetic fields (EMF) are widely used for therapeutic tissue heating. Although short-wave diathermy (27.12,MHz) is the most popular treatment modality, quantitative data on patient's exposure have been lacking. By numerical simulation with the numerical anatomical model NORMAN, intracorporal distributions of specific absorption rates (SAR) were investigated for different treatment scenarios and applicators. Quantitative data are provided for exposures of target treatment areas as well as for vulnerable regions such as the eye lenses, central nervous system, and testes. Different applicators and distances were investigated. Capacitive and inductive applicators exhibit quite a different heating efficiency. It could be shown that for the same output power therapeutic heat deposition can vary by almost one order of magnitude. By mimicking therapist's practice to use patient's heat perception as an indicator for output power setting, numerical data were elaborated demonstrating that muscle tissue exposures may be several times higher for inductive than for capacitive applicators. Presented quantitative data serve as a guide for power adjustment preventing relevant overexposures without compromising therapy; they also provide a basis for estimating target tissue heat load and developing therapeutic guidelines. Bioelectromagnetics 31:12,19, 2010. © 2009 Wiley-Liss, Inc. [source] 4365: The role of transpupillary thermotherapy in combined treatment of retinoblastomaACTA OPHTHALMOLOGICA, Issue 2010SV SAAKYAN Purpose Retinoblastoma (RB) is one of the most serious ophthalmic pathology in childhood. Treatment options that provide eye preservation include chemotherapy, brachytherapy, external beam radiation, cryotherapy and laser treatment. The aim of our study is to evaluate efficiency of transpupillary thermotherapy (TTT) as a part of combined treatment of RB. Methods Our group consists of 30 RB patients (34 eyes). All patients received systemic chemotherapy (Carboplatin and Vincristine). Tumor thickness before TTT varied from 0.9 to 2.6 mm, tumor base diameter varied from 2 to 10 mm. Seven patients had monolateral RB, others had bilateral lesion. Five patients were treated with brachytherapy before TTT. TTT was performed using infrared diode laser Nidec DC 3300. Exposure time was 60 seconds. Width of laser beam was from 1000 to 2000 nm. TTT power setting varied from 600 to 900 mW. Eleven patients had TTT more then once. Follow-up period after TTT was up to 24 months. Results Control examination after TTT showed good response to the treatment in 27 eyes (79.4%). After TTT we saw hyperpigmented scar on the eye fundus at the place of previous tumor location, on OCT it looked like hyper-reflective stripe replacing all layers of a retina. Seven eyes (20.6%) were resistant to TTT, five of them were successfully treated by additional brachytherapy. Two eyes were enucleated because of uncontrolled tumor growth. Evaluation of metastatic disease in all patients revealed no signs of metastasis at the time of treatment or during follow-up. Conclusion TTT can be used in combined treatment of RB for small multifocal lesions. The method is rather simple and uncomplicated. Patients treated with TTT have better visual prognosis in comparison with brachytherapy. [source] Subretinal pigment dispersion following transpupillary thermotherapy for choroidal melanomaACTA OPHTHALMOLOGICA, Issue 4 2002Hayyam Kiratli ABSTRACT. Purpose:, To report the case of a patient who developed considerable subretinal pigment/debris dispersion following transpupillary thermotherapy (TTT). This type of tumour response is extremely rare with this relatively new therapeutic modality. Methods:, A 50-year-old man with a left juxtapapillary choroidal melanoma measuring 8 × 6 × 4.3 mm was treated with 810 nm diode laser TTT administered in two sessions. Spot size was 3 mm and the power setting was 450 mW. Results:, Four months after the first treatment session, a considerable amount of pigment/debris was seen to have dispersed in the subretinal space, accumulating mainly in the macular area. Over a 12-month follow-up, the tumour showed progressive shrinkage without any change in the amount or location of the shed pigment/debris. No new tumour formation, recurrence or systemic metastases were detected. Conclusion:, Subretinal pigment/debris dispersion is an unusual complication after TTT and requires close follow-up. There has been no short-term compromise on the life or visual acuity of this patient. [source] Ex vivo study of the adhesion of an epoxy-based sealer to human dentine submitted to irradiation with Er : YAG and Nd : YAG lasersINTERNATIONAL ENDODONTIC JOURNAL, Issue 12 2005M. D. Sousa-Neto Abstract Aim, To evaluate the adhesion of an epoxy-based sealer to human dentine submitted to irradiation with Er : YAG or Nd : YAG laser at various parameters. Methodology, Ninety maxillary canine teeth were sectioned transversely at the cemento-enamel junction and at the root tip to leave an 8-mm-long cylinder. The tooth specimen was centred in a metallic ring (16 mm diameter and 8 mm height) and embedded in acrylic resin. The root canals were prepared using a low-speed handpiece and a conical diamond bur, which was attached to a paralleling device. This bur was lowered to a depth previously determined by a silicone stop. Specimens were divided into nine groups: group I, dentine was treated with 2 mL of 17% EDTAC for 5 min. Groups II,V were irradiated with Er : YAG laser at the following parameters: group II , 8 Hz and 200 mJ input (120 mJ output); group III , 8 Hz and 400 mJ input (240 mJ output); group IV , 16 Hz and 200 mJ input (120 mJ output); group V , 16 Hz and 400 mJ input (240 mJ output). Groups VI,IX were irradiated with Nd : YAG laser at the following parameters: group VI , 10 Hz and 1 W input (0.4 W output); group VII , 10 Hz and 2 W input (0.8 W output); group VIII , 15 Hz and 1 W input (0.4 W output); group IX , 15 Hz and 2 W input (0.8 W output). The root canals were filled with an epoxy-based root canal sealer and submitted to a push-out test. Results, Statistical analysis showed significant differences (P < 0.01) between Er : YAG and Nd : YAG laser treatments at the higher frequencies compared with 17% EDTAC. Greater adhesion values were obtained for groups IV and V (Er : YAG laser) and groups VIII and IX (Nd : YAG laser), which were statistically different from groups II and III (Er : YAG laser) and groups VI and VII (Nd : YAG laser). Treatment with only 17% EDTAC had the lowest adhesion values. Conclusions, An increase in frequency, independent of power settings, of the lasers used in this study increased adhesion of an epoxy-based root canal sealer. [source] Laser-induced phase changes in olivine FePO4: a warning on characterizing LiFePO4 -based cathodes with Raman spectroscopyJOURNAL OF RAMAN SPECTROSCOPY, Issue 2 2009Christopher M. Burba Abstract Raman spectroscopy is an excellent technique for probing lithium intercalation reactions of many diverse lithium ion battery electrode materials. The technique is especially useful for probing LiFePO4 -based cathodes because the intramolecular vibrational modes of the PO43, anions yield intense bands in the Raman spectrum, which are sensitive to the presence of Li+ ions. However, the high power lasers typically used in Raman spectroscopy can induce phase transitions in solid-state materials. These phase transitions may appear as changes in the spectroscopic data and could lead to erroneous conclusions concerning the delithiation mechanism of LiFePO4. Therefore, we examine the effect of exposing olivine FePO4 to a range of power settings of a 532-nm laser. Laser power settings higher than 1.3 W/mm2 are sufficient to destroy the FePO4 crystal structure and result in the formation of disordered FePO4. After the laser is turned off, the amorphous FePO4 compound crystallizes in the electrochemically inactive ,-FePO4 phase. The present experimental results strongly suggest that the power setting of the excitation laser should be carefully controlled when using Raman spectroscopy to characterize fundamental lithium ion intercalation processes of olivine materials. In addition, Raman spectra of the amorphous intermediate might provide insight into the ,-FePO4 to olivine FePO4 phase transition that is known to occur at temperatures higher than 450 °C. Copyright © 2008 John Wiley & Sons, Ltd. [source] Electrophoretic patterns of microwaved and ,-irradiated beef liver proteinsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 10 2001S Farag Abstract The effects of ,-irradiation treatments (2.5, 5 and 10,kGy) and microwaves generated from an oven at low and defrost power settings for 0.5, 1 and 2,min on the total proteins and protein patterns of beef liver immediately after treatment and during frozen storage (,18,°C) for different periods were studied. Chemical analyses indicated that the protein content of beef liver was reduced after exposure to ,-radiation or microwaves and also during frozen storage. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) was used to illustrate the changes in protein bands of different molecular weights and their percentages before and after exposure to gamma and microwave radiation. The main effect of ,-radiation on the protein patterns of beef liver was the disappearance of some high-molecular-weight protein bands and the development of other bands characterised by moderate and low molecular weights. This finding indicates the degradation of beef liver proteins by ,-irradiation. In contrast, microwave treatment caused an increase in the levels of high-molecular-weight protein bands with a concomitant decrease in low-molecular-weight protein bands. This phenomenon demonstrates the polymerisation of low-molecular-weight proteins under the influence of microwaves. © 2001 Society of Chemical Industry [source] Selective transcutaneous delivery of energy to porcine soft tissues using intense ultrasound (IUS),,LASERS IN SURGERY AND MEDICINE, Issue 2 2008W. Matthew White MD Abstract Objective Various energy delivery systems have been utilized to treat superficial rhytids in the aging face. The Intense Ultrasound System (IUS) is a novel modality capable of transcutaneously delivering controlled thermal energy at various depths while sparing the overlying tissues. The purpose of this feasibility study was to evaluate the response of porcine tissues to various IUS energy source conditions. Further evaluation was performed of the built-in imaging capabilities of the device. Materials and Methods Simulations were performed on ex vivo porcine tissues to estimate the thermal dose distribution in tissues after IUS exposures to determine the unique source settings that would produce thermal injury zones (TIZs) at given depths. Exposures were performed at escalating power settings and different exposure times (in the range of 1,7.6 J) using three IUS handpieces with unique frequencies and focal depths. Ultrasound imaging was performed before and after IUS exposures to detect changes in tissue consistency. Porcine tissues were examined using nitro-blue tetrazolium chloride (NBTC) staining sensitive for thermal lesions, both grossly and histologically. The dimensions and depth of the TIZs were measured from digital photographs and compared. Results IUS can reliably achieve discrete, TIZ at various depths within tissue without surface disruption. Changes in the TIZ dimensions and shape were observed as source settings were varied. As the source energy was increased, the thermal lesions became larger by growing proximally towards the tissue surface. Maximum lesion depth closely approximated the pre-set focal depth of a given handpiece. Ultrasound imaging detected well-demarcated TIZ at depths within the porcine muscle tissue. Conclusion This study demonstrates the response of porcine tissue to various energy dose levels of Intense Ultrasound. Further study, especially on human facial tissue, is necessary in order to understand the utility of this modality in treating the aging face and potentially, other cosmetic applications. Lesers Surg. Med. 40:67,75, 2008. © 2008 Wiley-Liss, Inc. [source] | |||||||||||||