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The effects of the saliva and oral probiotic supplements on roughness, friction and microhardness of the stainless steel (SS) and nickel‐titanium (NiTi) alloys used in dentistry was studied. The specimens of stainless steel, uncoated, rhodium‐coated and nitrided NiTi were exposed to artificial saliva with pH 4.8 and artificial saliva with addition of probiotic supplements containing bacteria Lactobacillus reuteri Prodentis through 28 days. First 5 days specimens were subjected to thermocycling to simulate intraoral conditions, 2500 cycles from 5 °C to 50 °C and the following days to the temperature of the 37±2 °C. Analyses demonstrated that oral probiotic supplements do not influence microhardness, roughness or friction of stainless steel above the influence of saliva. Probiotics increase roughness in NiTi, but without significant influence on friction, while microhardness in NiTi is not influenced. Surface nitriding reduces the influence of probiotics on roughness while rhodium coating increases it. [ABSTRACT FROM AUTHOR]

Ultra-thin bonded posterior occlusal veneers represent a conservative alternative to traditional inlays and complete coverage crowns for the treatment of severe erosive lesions. Consequential to the development of CAD/CAM restorative dental materials, limited data regarding their survival rate and fracture strength is available when they are used as occlusal veneers. The aim of this study is to evaluate the influence of thermomechanical loading on fracture strength of minimally invasive occlusal veneer restorations fabricated from different CAD/CAM materials and bonded to human maxillary molars. Twenty extracted maxillary molars were randomly assigned to two groups (n=10): zirconia-reinforced lithium silicate (Celtra Duo, Dentsply Sirona) (CD), or nano-hybrid ceramic (Mazic, Duro, Vericom) (MD). The teeth received a preparation for a conservative full-coverage occlusal veneer with a 1-mm cusp reduction with a marginal chamfer. Restorations were obtained using the CEREC chair-side (CEREC MC X) and luted with a two-step self-etch adhesive system (Clearfil SE, Kuraray) and a dual resin cement (Variolink II, Ivoclar-Vivadent). After thermomechanical aging (240.000 cycles at 50 N with 5-55°C thermocycling) with a chewing simulator (CS-4.4, SD Mechatronik) the specimens were loaded to fracture using a universal testing machine. The statistical analysis was performed using one-way ANOVA and Tukey's test. All specimens survived the fatigue test. MD showed the higher mean fracture load value (3394±914 N) with statistically significant differences than CD (2352±772 N). MD showed the highest values of fracture resistance, supporting its use for occlusal veneers. [ABSTRACT FROM AUTHOR]

Ocean acidification is one of the most dramatic effects of the massive atmospheric release of anthropogenic carbon dioxide (CO2) that has occurred since the Industrial Revolution, although its effects on marine ecosystems are not well understood. Submarine volcanic hydrothermal fields have geochemical conditions that provide opportunities to characterise the effects of elevated levels of seawater CO2 on marine life in the field. Here, we review the geochemical aspects of shallow marine CO2-rich seeps worldwide, focusing on both gas composition and water chemistry. We then describe the geochemical effects of volcanic CO2 seepage on the overlying seawater column. We also present new geochemical data and the first synthesis of marine biological community changes from one of the best-studied marine CO2 seep sites in the world (off Vulcano Island, Sicily). In areas of intense bubbling, extremely high levels of pCO2 (> 10,000 μatm) result in low seawater pH (< 6) and undersaturation of aragonite and calcite in an area devoid of calcified organisms such as shelled molluscs and hard corals. Around 100–400 m away from the Vulcano seeps the geochemistry of the seawater becomes analogous to future ocean acidification conditions with dissolved carbon dioxide levels falling from 900 to 420 μatm as seawater pH rises from 7.6 to 8.0. Calcified species such as coralline algae and sea urchins fare increasingly well as sessile communities shift from domination by a few resilient species (such as uncalcified algae and polychaetes) to a diverse and complex community (including abundant calcified algae and sea urchins) as the seawater returns to ambient levels of CO2. Laboratory advances in our understanding of species sensitivity to high CO2 and low pH seawater, reveal how marine organisms react to simulated ocean acidification conditions (e.g., using energetic trade-offs for calcification, reproduction, growth and survival). Research at volcanic marine seeps, such as those off Vulcano, highlight consistent ecosystem responses to rising levels of seawater CO2, with the simplification of food webs, losses in functional diversity and reduced provisioning of goods and services for humans. [ABSTRACT FROM AUTHOR]

Abundant clay burnt plaster remains and a few flaked tools, including an obsidian artefact, found on the ground surface not far from Trieste (north-eastern Italy) provide rare evidence of a possible prehistoric open-air occupation in the area. To confirm and detail their ancient origin, a plaster sample has been dated between 4000 and 2000 B.C. via thermoluminescence. Outer and inner structure of selected plaster samples has been characterized using several techniques, i.e. X-ray diffraction, scanning electron microscopy and X-ray computed micro-tomography, obtaining information about their production technology. The last technique has allowed to image and virtually extract vegetal remains and imprints. Their 3D morphological study has contributed to collect information about the ancient environment and has provided clues to define the plaster production season. The provenance of the obsidian artefact from Lipari Island, revealed by prompt gamma activation analysis, suggests that the finding site was part of long-distance connection systems and probably worked as intermediate point between the north-eastern Adriatic coastal areas and the inner Karst plateau. [ABSTRACT FROM AUTHOR]

The events that have characterized the end of 20th century and the begining of 21th century seem to bring the occidental civilization and the whole Earth to an age of important sociopolitical, economical and ambiental changes, with catastrophic consequences for the whole umanity. The resulted emegency state brings the poor population to the mass migration to occidental countries. All of these don't develop global strategies to solve the problem, but they prefer to adopt only provvisional solutions; only the magisterium of the Pope Bergoglio seems to focalize on the problem, and it identifies as the only possible solution the propension to the needs of poor and closer people and the world, with the eyes of sharing and mercy. This work wants to show how the land of Salento, according to its millenary history of welcome and integration, replies to the problems of migration, that see it in the front line since 1991, in the best way ever. Also, basing on the datas collected by the local Healt Institution, it's recognized that, according to the elements collected at nazional and European level, the fear of an healt emergency for the natives people, because of migrants coming, is totally unfounded. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to determine the in vitro microbiological performances of a lactose-modified chitosan (Chitlac) coating inside which silver nanoparticles were embedded (Chitlac-nAg) for BisGMA/TEGDMA methacrylic specimens.Methods: Different concentrations of nAg inside Chitlac coating were tested (1 mM, 2 mM, 5 mM). Specimen surface was analyzed by means of field-emission scanning electron microscopy (FEISEM) and energy-dispersive X-ray spectroscopy (EDS). A 48 h monospecific Streptococcus mutans biofilm was developed over the specimen surfaces using a modified drip-flow bioreactor; adherent viable biomass was assessed by MTT test and biofilm was imaged by confocal laser-scanning microscopy (CLSM).Results: The presence of finely dispersed nanoparticles inside the Chitlac coating was confirmed by FEISEM and EDS analysis. All nanoparticles were embedded in the Chitlac coating layer. Chitlac-nAg coatings were able to significantly decrease biofilm formation depending on the nAg concentration, reaching a -80% viable biomass decrease when the 5 mM nAg-Chitlac group was confronted to non-coated control specimens. CLSM analysis did not provide evidence of a contact-killing activity, however the antibacterial Chitlac-nAg coating was able to alter biofilm morphology preventing the development of mature biofilm structures.Conclusions: The microbiological model applied in this study helped in assessing the antibacterial properties of a coating designed for methacrylate surfaces.Clinical Significance: A microbiological model based on a bioreactor-grown biofilm is useful for preliminary in vitro tests of dental materials. In translational terms, an antibacterial nanocomposite coating based on Chitlac-nAg and designed to be applied to methacrylic surfaces may be a promising way to obtain dental materials able to actively prevent secondary caries. [ABSTRACT FROM AUTHOR]

The plant cell wall is an important factor for determining cell shape, function and response to the environment. Secondary cell walls, such as those found in xylem, are composed of cellulose, hemicelluloses and lignin and account for the bulk of plant biomass. The coordination between transcriptional regulation of synthesis for each polymer is complex and vital to cell function. A regulatory hierarchy of developmental switches has been proposed, although the full complement of regulators remains unknown. Here we present a protein-DNA network between Arabidopsis thaliana transcription factors and secondary cell wall metabolic genes with gene expression regulated by a series of feed-forward loops. This model allowed us to develop and validate new hypotheses about secondary wall gene regulation under abiotic stress. Distinct stresses are able to perturb targeted genes to potentially promote functional adaptation. These interactions will serve as a foundation for understanding the regulation of a complex, integral plant component. [ABSTRACT FROM AUTHOR]

3D-printed provisional restorations can be fabricated using additive manufacturing (AM) technologies. However, little information about their performance is available. The aim of this study was to compare the fatigue resistance of 3-teeth provisional resin restorations obtained by 3D printing with those made from polymethylmethacrylate (PMMA) blocks using a CAD/CAM system. A titanium master model for 3-teeth fixed dental prostheses (FDPs) (abutment teeth 45 and 47) was prepared. The master model was scanned and 14 provisional FDPs were produced using respectively: group 1 (N=7): CAD/CAM + BreCAM HIPC-Bredent (BH); group 2 (N=7): 3D printing + NextDent (ND). The FDPs were cemented on the titanium master model with a provisional cement (Temp Bond, Kerr) and submitted to a 5-step incremental cyclic isometric loading: step 1: 5.000 cycles at 10 Hz with 200 N compressive load; steps 2 to 5: 30.000 cycles at 3 Hz with a compressive load respectively of 400 N, 600 N, 800 N and 950 N. Group 1 and 2 were compared using the life table survival analysis and t-test. In group 1 (BH), only 5 specimens endured the entire fatigue process, while 2 specimens failed at 950 N. In group 2 (ND), 1 specimen failed at 400 N, 5 specimens (ND) failed at 600 N) and 1 specimen failed at 800 N. PMMA CAD/CAM provisional FDPs showed higher fatigue resistance when compared to the ones made via 3D printing. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: The aim of the study was to evaluate the contraction stress, microhardness and polymerization kinetics of three self-adhesive cements vs. conventional dual-cure resin cement. Methods: Cements tested were: RelyX Unicem (3M ESPE, St. Paul, MN, USA), MaxCem Elite (Kerr, Orange, CA, USA), Clearfil SA Cement (Kuraray, Tokyo, Japan) and Duolink (Bisco Inc., Schaumburg, IL, USA). Cements were irradiated with a LED-curing unit (bluephase, IvoclarVivadent) for 20 or 40s and the contraction forces (N) generated during polymerization were continuously recorded for 6h with a universal testing machine. Polymerization kinetics were monitored using micro-Raman spectroscopy and degree of conversion was calculated. Vickers microhardness was also recorded. All measurements were performed at 10min and 6h. Data were statistically analyzed by three-way ANOVA with repeated measures and Tukey''s post hoc test (α =0.05). Results: Irrespective of exposure time, stress analysis ranked in the following order: Clearfil SA Cement

Abstract: Growth in engineering thermoplastic recycling has been slow over the past decade because the current technologies based on solid-state re-polymerization of degraded feedstock do not offer a cost advantage over the use of virgin materials. As a result, most recycling efforts focus on using degraded post-industrial or post-consumer plastics in low cost, low performance applications, such as fiber and film. To change this paradigm new technologies have been developed. However, these new technologies have not been successful because of limited property enhancement. In this work, highly tailored epoxy functional styrene-acrylic oligomers have been evaluated as chain extenders or recycling aids for condensation thermoplastics. These oligomers, when reacted in simple extrusion or injection molding equipment with virgin, post-industrial recycle or post-consumer recycled polyesters, polyamides, polycarbonates, polyurethanes, and their blends, effectively revert molecular weight degradation even at very small use levels (<1.5%). The resultant chain extended materials demonstrate mechanical and rheological properties similar to or greater than the corresponding virgin resins, at a minimal added cost. The ability of this technology to enhance properties without the need for solid-state re-polymerization, renders high end recycling economically attractive for a large number of high value added engineering applications. [Copyright &y& Elsevier]

A novel set of microstructures for on-wafer stress measurement is presented, based on a lancet principle, with dedicated design for the amplification of the dimensional variations induced by the internal stress of the structural material. A tilted arm geometry was adopted in order to maximize the strain induced movement, keeping the design relatively simple and robust and the lancet on the wafer plane. A set of simulations, as well as an analytical examination of the structure was performed to establish the optimal geometry: different tilt angles were simulated in a range between -200 and 200 MPa internal stress. Test structures were then realized by means of surface micromachining, adopting photoresist as sacrificial layer and electroplated gold as structural layer: the novel geometry was sided by traditional rotating structures [Sens. Actuators A 37/38 (1993) 756] and wafer curvature measurements to confirm the readout. Plastic regime simulations were adopted to analyze the behavior of the gold structures, based on a stress–strain curve obtained experimentally. [Copyright &y& Elsevier]