Coke formation in the dry reforming of methane was studied using a thermobalance (TG) and with a catalytic microreactor in the temperature range 800-950 K. Silica-supported and lanthana-supported nickel catalysts were examined. The effects of process variables such as temperature and gas composition (He dilution, CH4/CO2 ratio) on the coke formation rate were determined. The reactivity of H-2 On several kinds of carbon was also investigated. The morphology of the coke was studied by scanning electron microscopy (SEM). The induction times for coke formation were significantly affected by temperature and by the CO content in the feed gas. The results of catalytic tests were consistent with the TG measurements. The behaviour of SiO2 and La2O3 supported Ni catalysts agree with a mechanism in which the lanthana support plays an important role in the carbon deposition

We report on the photodegradation of diclofenac (DCF) by hydrothermal anatase nanocrystals either free or immobilized in porous silica matrix (TS) in connection to the type and amount of reactive oxygen species (ROS), in order to have deeper insight into their role in the photocatalysis and to provide an effective tool to implement the DCF mineralization. TiO2and TS exhibit a remarkable efficiency in the DCF abatement, supporting that the utilization of anatase nanoparticles with the highly reactive{001},{010}, and{101}exposed surfaces can be an effective way for enhancing the photooxidation even of the persistent pollutants. Furthermore, the hydrothermal TiO2, when immobilized in silica matrix, preserves its functional properties, combining high photoactivity with an easy technical use and recovery of the catalyst. The catalysts performances have been related to the presence of OH•,O21, andO2-•species by electron paramagnetic resonance spin-trap technique. The results demonstrated that the ROS concentration increases with the increase of photoactivity and indicated a significant involvement ofO21in the DCF degradation. The efficacy of TiO2when immobilized on a silica matrix was associated with the high ROS life time and with the presence of singlet oxygen, which contributes to the complete photomineralization of DCF.

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Background:The soft tissue healing and quality around dental implant is a current debated topic in the recent literature. The free gingival margin and the quantity and quality of the mucosa around teeth and surrounding dental implants still determine the hard and soft tissue healing status.Objective:The aim of this study is to assess inter and intra-operative measurement concordance of a method aimed at evaluating the apico-coronal migration of free gingival margin, using intra-oral photography.Methods:The method was tested on peri-implant tissues that were treated with a connective tissue graft on the second stage surgery. Thirty-eight measurements on 13 implants in 8 patients were recorded. An intra-oral photograph was taken for the graft and the provisional crown, which enclosed a circular landmark with a previously determined diameter. The landmark was prepared with a red-resin by the same technician. Before crown cementation, the landmark was calibrated with a digital calibrator by the main investigator, to determine the precise diameter up to two decimal numbers.Results:On the intra-oral photograph, the distance was measured from the most apical point of the determined landmark to the zenith of the gingiva, using an image-processing program designed for scientific multidimensional images (Image J). Three independent examiners took these measurements.Conclusion:The main advantage of the present non-invasive technique is that the spatial plane of the prosthetic landmarks is the same of the tooth unlike the utilization of periodontal probe, which is generally positioned on different plans in the space (generally more vestibular).