Effect of different light-curing techniques on hardness of a microhybrid dental composite resin

Coordenação de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)

Changes in irradiance and energy density in relation to different curing distances

The present study aimed to assess the influence of curing distance on the loss of irradiance and power density of four curing light devices. The behavior in terms of power density of four different dental curing devices was analyzed (Valo, Elipar 2, Radii-Cal, and Optilux-401) using three different distances of photopolymerization (0 mm, 4 mm, and 8 mm). All devices had their power density measured using a MARC simulator. Ten measurements were made per device at each distance. The total amount of energy delivered and the required curing time to achieve 16 J/cm2 of energy was also calculated. Data were statistically analyzed with one-way analysis of variance and Tukey’s tests (p < 0.05). The curing distance significantly interfered with the loss of power density for all curing light devices, with the farthest distance generating the lowest power density and consequently the longer time to achieve an energy density of 16 J/cm2 (p < 0.01). Comparison of devices showed that Valo, in extra power mode, showed the best results at all distances, followed by Valo in high power mode, Valo in standard mode, Elipar 2, Radii-Cal, and Optilux-401 halogen lamp (p < 0.01). These findings indicate that all curing lights induced a significant loss of irradiance and total energy when the light was emitted farther from the probe. The Valo device in extra power mode showed the highest power density and the shortest time to achieve an energy density of 16 J/cm2 at all curing distances.

Evaluation of the bleached human enamel by scanning electron microscopy

Since bleaching has become a popular procedure, the effect of peroxides on dental hard tissues is of great interest in research. Purpose: The aim of this in vitro study was to perform a qualitative analysis of the human enamel after the application of in-office bleaching agents, using Scanning Electron Microscopy (SEM). Materials and Methods: Twenty intact human third molars extracted for orthodontic reasons were randomly divided into four groups (n=5) treated as follows: G1- storage in artificial saliva (control group); G2- four 30-minute applications of 35% carbamide peroxide (total exposure: 2h); G3- four 2-hour exposures to 35% carbamide peroxide (total exposure: 8h); G4- two applications of 35% hydrogen peroxide, which was light-activated with halogen lamp at 700mW/cm2 during 7min and remained in contact with enamel for 20min (total exposure: 40min). All bleaching treatments adopted in this study followed the application protocols advised by manufacturers. Evaluation of groups submitted to 35% carbamide peroxide was carried out after two time intervals (30 minutes and 2 hours per session), following the extreme situations recommended by the manufacturer. Specimens were prepared for SEM analysis performing gold sputter coating under vacuum and were examined using 15kV at 500x and 2000x magnification. Results: Morphological alterations on the enamel surface were similarly detected after bleaching with either 35% carbamide peroxide or 35% hydrogen peroxide. Surface porosities were characteristic of an erosive process that took place on human enamel. Depression areas, including the formation of craters, and exposure of enamel rods could also be detected. Conclusion: Bleaching effects on enamel morphology were randomly distributed throughout enamel surface and various degrees of enamel damage could be noticed. Clinical significance: In-office bleaching materials may adversely affect enamel morphology and therefore should be used with caution.

Degree of conversion of nanofilled and microhybrid composite resins photo-activated by different generations of LEDs

Objective: This study aimed at evaluating the degree of conversion (DC) of four composite resins, being one nanofilled and 3 microhybrid resins, photo-activated with second- and third-generation light-emitting diodes (LEDs). Material and methods: Filtek (TM) Z350 nanofilled composite resins and Amelogen (R) Plus, Vit-l-escence (TM) and Opallis microhybrid resins were photo-activated with two second-generation LEDs (Radii-cal and Elipar Free Light (TM) 2) and one third-generation LED (Ultra-Lume LED 5) by continuous light mode, and a quartz halogen-tungsten bulb (QHT, control). After 24 h of storage, the samples were pulverized into fine powder and 5 mg of each material were mixed with 100 mg of potassium bromide (KBr). After homogenization, they were pressed, which resulted in a pellet that was evaluated using an infrared spectromer (Nexus 470, Thermo Nicolet) equipped with TGS detector using diffuse reflectance (32 scans, resolution of 4 cm(-1)) coupled to a computer. The percentage of unreacted carbon-carbon double bonds (% C=C) was determined from the ratio of absorbance intensities of aliphatic C=C (peak at 1637 cm-1) against internal standard before and after curing of the specimen: aromatic C-C (peak at 1610 cm-1). Results: The ANOVA showed a significant effect on the interaction between the light-curing units (LCUs) and the composite resins (p<0.001). The Tukey's test showed that the nanofilled resin (Filtek (TM) Z350) and Opallis when photo-activated by the halogen lamp (QTH) had the lowest DC compared with the other microhybrid composite resins. The DC of the nanofilled resin (Filtek (TM) Z350) was also lower using LEDs. The highest degrees of conversion were obtained using the third-generation LED and one of second-generation LEDs (Elipar Free Light (TM) 2). Conclusions: The nanofilled resin showed the lowest DC, and the Vit-l-escence (TM) microhybrid composite resin showed the highest DC. Among the LCUs, it was not possible to establish an order, even though the second-generation LED Radii-cal provided the lowest DC.

Bedeutung endogener und exogener Quellen reaktiver Sauerstoffspezies für die Entstehung des malignen Melanoms

Bedeutung endogener und exogener Quellen reaktiver Sauerstoffspezies für die Entstehung des malignen Melanoms Um zu überprüfen, ob reaktive Sauerstoffspezies (ROS) an der Entstehung des malignen Melanoms ursächlich beteiligt sind, wurde in dieser Arbeit der Einfluss von Mitochondrien als endogener und Licht als exogener ROS-Quelle untersucht.Nach Bestrahlung mit Licht (Halogenlampe 1000 W, 1125 kJ/m² zwischen 400-800 nm) reagierten M8,99-Melanomzellen sensitiver mit der Bildung oxidativer DNA-Basenmodifikationen als Hautfibroblasten des gleichen Melanompatienten. In einer anderen Melanomzelle (M2/02) war ein klarer Reparaturdefekt oxidativer DNA-Schäden zu beobachten. Bei viermaliger Bestrahlung mit Licht im Abstand von zwei Stunden (je 450 k/m²) nahm die Zahl induzierter oxidativer DNA-Modifikationen und Mikrokerne stetig zu. Durch Mehrfachbestrahlung mit Kantenfilter (? > 395 nm) konnte gezeigt werden, dass ein Teil der Mikrokerne im Bereich sichtbaren Lichts entsteht. Mitochondrien könnten als endogene Hauptquelle für ROS an der Entstehung oxidativer DNA-Modifikationen und des malignen Melanoms beteiligt sein. Die Abwesenheit der mitochondrialen Atmungskette bewirkte in dieser Arbeit eine nachhaltige Abnahme der intrazellulären ROS-Bildung bzw. ihre Stimulation durch mitochondriale Gifte eine starke Zunahme. Da in beiden Fällen kein Effekt auf die Zahl der oxidativen DNA-Modifikationen zu beobachten war, kann die mitochondriale ROS-Produktion nicht auf diesem Weg zur Melanom-Entstehung beitragen.

Calibração radiométrica de instrumentação óptica espectrofotométrica

Os espectrómetros instalados a bordo de satélites e à superfície da Terra têm desempenhado um papel fundamental na compreensão da química e dinâmica da atmosfera e na monitorização da poluição ambiental. O SPATRAM (SPectrometer for Atmosferic TRAcers Measurements) é um espectrómetro ultravioleta – Visível que compreende a região espectral entre 250-950nm e se encontra instalado no Instituto de Ciências da Terra (ICT) desde Abril de 2004. Enquanto isso, em 2012, um novo modelo do instrumento SPATRAM foi desenvolvido no ICT e foi chamado SPATRAM2. O objectivo do trabalho proposto é a calibração radiométrica do espectrómetro SPATRAM2, utilizando uma lâmpada de halogéneo e uma esfera de integração. A calibração radiométrica do sistema SPATRAM2 permitirá obter a radiação solar directa, com alta resolução espectral, o que actualmente não se encontra disponível. Este tipo de medição poderá ter um papel importante na investigação e desenvolvimento na área da energia solar e aplicações; Radiometric Calibration of Spectrophotometric Optical Instrumentation Abstract: Spectrometers installed aboard satellites and located on Earth’s surface have played a fundamental role to understand atmosphere’s chemistry and dynamic and to monitor environmental pollution. The SPATRAM (SPectrometer for Atmosferic TRAcers Measurements) instrument is an ultraviolet spectrometer – visible that covers spectral region between 250-950nm and it is installed in Instituto de Ciências da Terra (Institute of Earth Sciencies), ICT, since April 2004. Meanwhile, in 2012, a new model of SPATRAM instrument was developed in ICT and was called SPATRAM2. The goal of this project is the radiometric calibration of the SPATRAM2 spectrometer using a halogen lamp and an integrating sphere. Radiometric calibration of SPATRAM2 system will provide direct solar radiation, with high spectral resolution, that is not available nowadays. This type of measurement may play an important role in solar energy’s progress and investigation.

Mucosal and systemic anti-GAG immunity induced by neonatal immunization with HIV LAMP/gag DNA vaccine in mice

Vaccines capable of inducing mucosal immunity in early postnatal life until adulthood, protecting early sexual initiation, should be considered as strategies to vaccination against HIV. The HIV-1 GAG protein as a chimera with the lysosome-associated membrane protein (LAMP/gag), encoded by a DNA vaccine, is targeted to the endosomal/lysosomal compartment that contains class II MHC molecules and has been shown to be immunogenic in adult mice. Assuming that one such strategy could help to overcome the immunological immaturity in the early postnatal period, we have evaluated the systemic and mucosal immunogenicity of LAMP/gag immunization in neonatal mice. Intranasal immunization with LAMP/gag vaccine induced higher levels of sIgA and IgG anti-GAG antibodies in intestinal washes than did the gag vaccine. The combination of ID injections and the IN protocol with the chimeric vaccine promoted the increase of Ab levels in sera. Both vaccines induced splenic IFN-gamma- secreting cells against GAG peptide pools, as well as in vivo cytotoxic T lymphocyte (CTL) function, and increased the percentage of CD8+ T cells to the immunodominant class I peptide in gut and spleen. However, only the chimeric vaccine was able to enhance Th1/Th2 cytokine secretion in response to class II GAG peptide and to enhance IL-4-secreting cells against GAG peptides and p24 protein stimuli. Long-lasting humoral and cellular responses were detected until adult age, following neonatal immunization with the chimeric vaccine. The LAMP/gag vaccination was able to induce potent GAG-specific T and B cell immune responses in early life which are essential to elicit sustained and long-lasting mucosal and systemic humoral response. (C) 2010 Elsevier GmbH. All rights reserved.

Immunization of neonatal mice with LAMP/p55 HIV gag DNA elicits robust immune responses that last to adulthood

Successful T cell priming in early postnatal life that can generate effective long-lasting responses until adulthood is critical in HIV vaccination strategies because it prevents early sexual initiation and breastfeeding transmission of HIV. A chimeric DNA vaccine encoding p55 HIV gag associated with lysosome-associated membrane protein 1 (LAMP-1; which drives the antigen to the MIIC compartment), has been used to enhance cellular and humoral antigen-specific responses in adult mice and macaques. Herein, we investigated LAMP-1/gag vaccine immunogenicity in the neonatal period in mice and its ability to generate long-lasting effects. Neonatal vaccination with chimeric LAMP/gag generated stronger Gag-specific immune responses, as measured by the breadth of the Gag peptide-specific IFN-gamma, proliferative responsiveness, cytokine production and antibody production, all of which revealed activation of CD4+ T cells as well as the generation of a more robust CTL response compared to gag vaccine alone. To induce long-lived T and B cell memory responses, it was necessary to immunize neonates with the chimeric IAMP/gag DNA vaccine. The LAMP/gag DNA vaccine strategy could be particularly useful for generating an anti-HIV immune response in the early postnatal period capable of inducing long-term immunological memory. (C) 2010 Elsevier Inc. All rights reserved.

Micro-hardness evaluation of a micro-hybrid composite resin light cured with halogen light, light-emitting diode and argon ion laser

This in vitro study aimed to determine whether the micro-hardness of a composite resin is modified by the light units or by the thickness of the increment. Composite resin disks were divided into 15 groups (n = 5), according to the factors under study: composite resin thickness (0 mm, 1 mm, 2 mm , 3 mm and 4 mm) and light units. The light activation was performed with halogen light (HL) (40 s, 500 mW/cm(2)), argon ion laser (AL) (30 s, 600 mW/cm(2)) or light-emitting diode (LED) (30 s, 400 mW/cm(2)). Vickers micro-hardness tests were performed after 1 week and were carried out on the top surface (0 mm-control) and at different depths of the samples. Analysis of variance (ANOVA) and Tukey tests (P a parts per thousand currency signaEuro parts per thousand 0.05) revealed no statistically significant difference among the light units for the groups of 0 mm and 1 mm thickness. At 2 mm depth, the AL was not statistically different from the HL, but the latter showed higher micro-hardness values than the LED. In groups with 3 mm and 4 mm thickness, the HL also showed higher micro-hardness values than the groups activated by the AL and the LED. Only the HL presented satisfactory polymerization with 3 mm of thickness. With a 4 mm increment no light unit was able to promote satisfactory polymerization.

Halogen-bonded tris (2,4-Bis(trichloromethyl)-1,3,5,triazapentadienato)-M(III) [M = Mn, Fe, Co] complexes and their catalytic activity in the peroxidative oxidation of 1-phenylethanol to acetophenone

One-pot template condensation of CCl3C=N with ammonia on a metal source [MnCl2 center dot 4H(2)O, FeCl3 center dot 6H(2)O or Co(CH3COO)(2)center dot 4H(2)O] in DMSO led to the formation of tris(2,4-bis(trichloromethyl)-1,3,5-triazapentadienato)-M(III) complexes, [M(NH=C(CCl3)NC(CCl3)=-NH}(3)]center dot n(CH3)(2)SO [M = Mn, n = 1 (1); M = Fe, n = 2 (2); M = Co, n = 2 (3)1, which were characterized using elemental analysis, and IR, ESI-MS and single-crystal X-ray analysis. The role of inter- and intramolecular non-covalent halogen and hydrogen bonds in the synthesis of 1-3 is discussed. It is shown that the crystal ionic radii of the metal ions [68.5 (Co) < 69 (Fe) < 72 (Mn), pm] are related to the corresponding Cl center dot center dot center dot Cl distances [3.178 (3) > 3.155 (2) > 3.133 (1) Al. Compounds 1-3 and the related di(triazapentadienato)-Cu(v) complex [Cu(NH=C(CCl3)NC(CCl3)=NH}2]center dot 2(CH3)(2)SO (4) act as catalyst precursors for the additive-free microwave (MW) assisted homogeneous oxidation of 1-phenylethanol with tert-butylhydroperoxide (TBHP), leading to the formation of acetophenone with yields up to 99% and TONs up to 5.0 x 10(3) after 1 h of low power (10 W) MW irradiation.

New RuII(arene) complexes with halogen-substituted bis- and tris(pyrazol-1-YL)borate ligands

[RuCl(arene)(-Cl)](2) dimers were treated in a 1:2 molar ratio with sodium or thallium salts of bis- and tris(pyrazolyl)borate ligands [Na(BpBr3)], [Tl(TpBr3)], and [Tl(Tp(iPr,4Br))]. Mononuclear neutral complexes [RuCl(arene)((2)-BpBr3)] (1: arene=p-cymene (cym); 2: arene=hexamethylbenzene (hmb); 3: arene=benzene (bz)), [RuCl(arene)((2)-TpBr3)] (4: arene=cym; 6: arene=bz), and [RuCl(arene)((2)-Tp(iPr,4Br))] (7: arene=cym, 8: arene=hmb, 9: arene=bz) have been always obtained with the exception of the ionic [Ru-2(hmb)(2)(-Cl)(3)][TpBr3] (5), which formed independently of the ratio of reactants and reaction conditions employed. The ionic [Ru(CH3OH)(cym)((2)-BpBr3)][X] (10: X=PF6, 12: X=O3SCF3) and the neutral [Ru(O2CCF3)(cym)((2)-BpBr3)] (11) have been obtained by a metathesis reaction with corresponding silver salts. All complexes 1-12 have been characterized by analytical and spectroscopic data (IR, ESI-MS, H-1 and (CNMR)-C-13 spectroscopy). The structures of the thallium and calcium derivatives of ligand TpBr3, [Tl(TpBr3)] and [Ca(dmso)(6)][TpBr3](2)2DMSO, of the complexes 1, 4, 5, 6, 11, and of the decomposition product [RuCl(cym)(Hpz(iPr,4Br))(2)][Cl] (7) have been confirmed by using single-crystal X-ray diffraction. Electrochemical studies showed that 1-9 and 11 undergo a single-electron (RuRuIII)-Ru-II oxidation at a potential, measured by cyclic voltammetry, which allows comparison of the electron-donor characters of the bis- and tris(pyrazol-1-yl)borate and arene ligands, and to estimate, for the first time, the values of the Lever E-L ligand parameter for BpBr3, TpBr3, and Tp(iPr,4Br). Theoretical calculations at the DFT level indicated that both oxidation and reduction of the Ru complexes under study are mostly metal-centered with some involvement of the chloride ligand in the former case, and also demonstrated that the experimental isolation of the (3)-binuclear complex 5 (instead of the mononuclear 5) is accounted for by the low thermodynamic stability of the latter species due to steric reasons.

MALARIA DIAGNOSIS BY LOOP-MEDIATED ISOTHERMAL AMPLIFICATION (LAMP) IN THAILAND

The loop-mediated isothermal amplification method (LAMP) is a recently developed molecular technique that amplifies nucleic acid under isothermal conditions. For malaria diagnosis, 150 blood samples from consecutive febrile malaria patients, and healthy subjects were screened in Thailand. Each sample was diagnosed by LAMP, microscopy and nested polymerase chain reaction (nPCR), using nPCR as the gold standard. Malaria LAMP was performed using Plasmodiumgenus and Plasmodium falciparum specific assays in parallel. For the genus Plasmodium, microscopy showed a sensitivity and specificity of 100%, while LAMP presented 99% of sensitivity and 93% of specificity. For P. falciparum, microscopy had a sensitivity of 95%, and LAMP of 90%, regarding the specificity; and microscopy presented 93% and LAMP 97% of specificity. The results of the genus-specific LAMP technique were highly consistent with those of nPCR and the sensitivity of P. falciparum detection was only marginally lower.

Creació d'una plataforma LAMP mitjançant Puppet

Implementació del sistema de gestió de configuracions Puppet per configurar desde zero una plataforma LAMP.

Pseudophakic Retinal Detachment Surgery by 23 G Vitrectomy using Slit-Lamp and Non-Contact 90 D Lens.

Background: The purpose of this study is to report the anatomic and functional results of primary 23 G vitrectomy using slit-lamp and non-contact 90 D lens for the treatment of pseudophakic rhegmatogenous retinal detachment. Patients and Methods: Pseudophakic eyes were operated by 23 G vitrectomy using slit-lamp and non-contact 90 D lens, internal subretinal fluid drainage, cryopexy and internal gas tamponade. The preoperative and postoperative characteristics were analysed. Main outcome measures were anatomic success rates after initial surgical intervention and after reoperation for primary failures, visual outcome at the last follow-up visit, and complications. Results: 46 pseudophakic eyes were included in this retrospective study (October 2013- January 2014). In 40 cases, sulfur hexafluoride 23 % gastamponade was used, silicone oil in 6 cases (13 %). The retina was reattached successfully after a single surgery in 44 eyes (96 %). Recurrence of retinal detachment occurred in 2 eyes. Final anatomic reattachment was obtained in 100 % after a second operation. Silicone oil was removed in all eyes. Visual acuity improved significantly from logMAR 0 (IQR 0 - 0.9) to logMAR 0 (IQR 0 - 0.2) (p < 0.005). Conclusions: Primary 23 G vitrectomy using slit-lamp and non contact 90 D lens for the treatment of pseudophakic rhegmatogenous retinal detachment provides a high anatomic and functional success rate and is associated with few complications.

Selective accumulation of mature DC-Lamp+ dendritic cells in tumor sites is associated with efficient T-cell-mediated antitumor response and control of metastatic dissemination in melanoma.

The clinical relevance of dendritic cells (DCs) at the tumor site remains a matter of debate concerning their role in the generation of effective antitumor immunity in human cancers. We performed a comprehensive immunohistochemical analysis using a panel of DC-specific antibodies on regressing tumor lesions and sentinel lymph nodes (SLNs) in melanoma patients. Here we show in a case report involving spontaneous regression of metastatic melanoma that the accumulation of DC-Lamp+ DCs, clustered with tumor cells and lymphocytes, is associated with local expansion of antigen-specific memory effector CTLs. These findings were extended in a series of 19 melanoma-positive SLNs and demonstrated a significant correlation between the density of DC-Lamp+ DC infiltrates in SLNs with the absence of metastasis in downstream lymph nodes. This study, albeit performed in a limited series of patients, points to a pivotal role of mature DCs in the local expansion of efficient antitumor T-cell-mediated immune responses at the initial sites of metastasis and may have important implications regarding the prognosis, staging, and immunotherapy of melanoma patients.