The purpose of this study was to assess the effect of a chitosan-based nanoformulation containing green tea on leathery (remaining) dentin subsurface microhardness. Size distribution, polydispersity index (PDI) and zeta potential (mV) of nanoformulations were previously determined by dynamic light scattering (DLS). Human dentin specimens were exposed to Streptococcusmutans for 14 d. Soft dentin were selectively removed by Er:YAG laser (n?=?30) or bur (n?=?30). Remaining dentin was biomodified with chitosan nanoparticles (Nchi, n?=?10) or green tea-loaded chitosan nanoparticles (Gt?+?Nchi, n?=?10) for 1 min. Control group (n?=?10) did not receive any treatment. Subsurface microhardness (Knoop) was evaluated in hard (sound) and soft dentin, and then, in leathery dentin and after its biomodification, at depths of 30, 60 and 90 μm from the surface. Nchi reached an average size of?≤?300 nm, PDI varied between 0.311 and 0.422, and zeta potential around?+?30 mV. Gt?+?Nchi reached an average size of?≤?350 nm, PDI?<?0.45, and zeta potential around?+?40 mV. Soft dentin showed significantly reduced microhardness at all depths (p?>?0.05). The subsurface microhardness was independent of choice of excavation method (p?>?0.05). At 30 µm from the surface, Gt?+?Nchi increased the leathery dentin microhardness compared to untreated group (p?<?0.05). Nchi promoted intermediate values (p?>?0.05). Both nanoformulations showed an average size less than 350 nm with nanoparticles of different sizes and stability along the 90-day period evaluated. Subsurface microhardness of bur-treated and laser-irradiated dentin was similar. At 30 µm, the biomodification with Gt?+?Nchi improved the microhardness of leathery dentin, independently of caries excavation method used.
Clinical Oral Investigations - The aim of this study was to investigate the effects of collagen cross-linking agents on nanomechanical and bonding properties of eroded dentin (ED), 24 h... 相似文献
The interest in non-invasive brain stimulation techniques is increasing in recent years. Among these techniques, transcranial direct current stimulation (tDCS) has been the subject of great interest among researchers because of its easiness to use, low cost, benign profile of side effects and encouraging results of research in the field. This interest has generated several studies and randomized clinical trials, particularly in psychiatry. In this review, we provide a summary of the development of the technique and its mechanism of action as well as a review of the methodological aspects of randomized clinical trials in psychiatry, including studies in affective disorders, schizophrenia, obsessive compulsive disorder, child psychiatry and substance use disorder. Finally, we provide an overview of tDCS use in cognitive enhancement as well as a discussion regarding its clinical use and regulatory and ethical issues. Although many promising results regarding tDCS efficacy were described, the total number of studies is still low, highlighting the need of further studies aiming to replicate these findings in larger samples as to provide a definite picture regarding tDCS efficacy in psychiatry. 相似文献
We made a retrospective longitudinal study from January 2000 to January 2003 to examine cases of immune reconstitution syndrome (IRS) and its incidence rate in tuberculosis (TB)-human immunodeficiency virus (HIV) co-infected patients. The incidence rate (IR) was calculated using a Poisson regression. The confidence interval (CI) that was stipulated was 95%. IRS occurred in 10/84 HIV and TB-positive patients; nine of them were on highly active anti-retroviral therapy (HAART) during a mean of 61.7 (+/- 59) days following the introduction of antiretrovirals. Lymph-node enlargement was the sole clinical manifestation. CD4 counts were <100 cells/mm(3)in 50% of the patients, at the time of TB diagnosis. All but two patients were treated with prednisone, and recovered from TB within a mean of 91 days (+/- 30 days). One relapse of TB was observed, but there were no IRS-related deaths. The incidence rate was higher (IR=11.18; CI, 1.41-88.76) in patients that had superficial lymph node enlargement at the moment of TB diagnosis (not associated with TB), extrapulmonary TB (IR=1.97; CI, 0.44-8.79), were antiretroviral naive (IR=1.85; CI, 0.48-7.16), and CD4 counts <100 cells/mm(3) (IR=1.50; CI, 0.40-5.59), although with a wide CI. IRS was frequent in our sample, occurred more frequently in HIV-naive patients with lymph-node enlargement and extrapulmonary TB. No cases of new pulmonary lesions or worsening of pulmonary infiltrates were observed. 相似文献
New ceramic formulations based on scheelite tailing were developed, and their potential in the ceramic industry was evaluated. Green bodies with different contents of scheelite tailing (0–8 wt%) were sintered (1150 °C, 1200 °C, and 1250 °C) and characterized in terms of the main mineralogical phases, microstructure, and physico-mechanical properties. The mullite was the main phase identified in all sintered temperatures. This result was also ratified with the aid of scanning electron microscope (SEM) images, in which small needles of the mullite were detected. The presence of mullite is required because it contributes to increasing the mechanical resistance of the material. The physico-mechanical properties measured (water absorption, linear shrinkage, apparent porosity, and flexural strength) were compared to the ISO 13006, and the samples sintered at 1150 °C presented potential to be used as semi-stoneware, while those sintered at 1200 °C and 1250 °C can be employed stoneware and porcelain tiles, respectively. 相似文献
The protozoan parasite Trypanosoma cruzi causes Chagas disease. Cardiac and adipose tissues are among the early targets of infection and are sites of persistent infection. In the heart and adipose tissue, T. cruzi infection results in an upregulation of pro-inflammatory mediators. In the heart, infection is associated with an increase in the markers of oxidative stress. To date, markers of oxidative stress have not been evaluated in adipose tissue in this infection. Brown and white adipose tissues were obtained from CD-1 mice infected with the Brazil strain of T. cruzi for 15, 30, and 130 days post infection. Protein carbonylation and lipid peroxidation assays were performed on these samples. There was an upregulation of these markers of oxidative stress at all time-points in both white and brown adipose tissue. Determinants of anti-oxidative stress were downregulated at similar time-points. This increase in oxidative stress during T. cruzi infection most likely has a deleterious effect on host metabolism and on the heart. 相似文献