Acoustic measurement of the low-energy excitations in Nd2-xCexCuO4

The complex dynamic Young's modulus of ceramic Nd2-xCexCuO4 with x = 0, 0.05 and 0.20 has been measured from 1.5 to 100 K at frequencies of 1-10 kHz. In the undoped sample the modulus starts decreasing below ~20 K, instead of approaching a constant value as in a normal solid. The modulus minimum has been interpreted in terms of paraelastic contribution from the relaxation of the Nd^3+ 4f electrons between the levels of the ground state doublet, which is split by the interaction with the antiferromagnetically ordered Cu sublattice. The value of the splitting is found to be 0.34 meV, in excellent agreement with inelastic neutron scattering, infrared and specific heat experiments. With doping, the anomaly shifts to lower temperature and decreases in amplitude, consistently with a reduction of the local field from the Cu sublattice.Comment: 5 pages, 2 figures, submitted to Eur. Phys. J.

Marginal sealing of relocated cervical margins of mesio-occluso-distal overlays.

We investigated the effect of cervical marginal relocation (CMR) on marginal sealing with two different viscosity resin composites, before adhesive cementation of composite computer-aided design/computer-assisted manufacture mesio-occluso-distal (MOD) overlays. Standardized MOD cavities prepared in 39 human molars were randomly assigned to three groups. The proximal margins on the mesial side were located 1 mm below the cementoenamel junction. On the distal side of the tooth, the margins were located 1 mm above the cementoenamel junction. In Groups 1 and 2, mesial proximal boxes were elevated with a hybrid composite (GC Essentia MD) and a flowable composite (GC G-ænial Universal Flo), respectively. CMR was not performed in Group 3. The overlays were adhesively cemented, and interfacial leakage was quantified by scoring the depth of silver nitrate penetration along the adhesive interfaces. Leakage score at the dentin-CMR composite interface did not significantly differ between the two tested composites but was significantly lower for Group 3. In all groups, scores were significantly higher at the dentin interface than at the enamel interface. These results indicate that the performance of flowable and microhybrid resin composites, as indicated by marginal sealing ability, is comparable for CMR

Consumer Liking and Value Perception of Mountain Cheese from Different Pasture Periods: Evidence for Mountain Systems Supporting Policies

Every year, mountain pastures show a progressive impoverishment of forage. The loss in grassland feed value restricts the production period of local Pecorino cheeses, which strongly depend on the vegetative cycle of the pasture linked to climatic conditions. The Monte Fietone mountain area (Macerata, Italy) has emblematic pasture flora during spring and early summer. This unique environment is normally used for rearing sheep, allowing regular production of local Pecorino cheeses from their milk, which is rich in vitamins and intrinsic floral aromas. Biologists and agronomists are giving increasing importance to these mountain food products. We conducted sensorial tests and experimental auctions to investigate recognition of the quality of this rare artisanal product. The results indicate considerable potential for economic differentiation. Accordingly, we recommend useful and applicable marketing and policy actions to support the sustainability of mountain grazing systems

Different Post Placement Strategies for the Restoration of Endodontically Treated Maxillary Premolars with Two Roots: Single Post vs Double Post

Aim and objective: The present study compared the fracture strength and failure pattern of endodontically treated, bi-rooted, maxillary premolars with different number of coronal walls and postendodontic restoration (one vs double post). Materials and methods: 105 premolars were divided into 3 groups according to the number of residual walls: control group (intact teeth; n= 15), group 1 (3 residual walls; n = 45), group 2 (2 residual walls; n = 45). Each test group was then divided into 3 subgroups (n = 15 each) according to postendodontic restoration: no post (A), 1 post (B) or 2 posts (C). A load was applied parallel to the longitudinal axis of the teeth, thus simulating physiological occlusion. ANOVA and Tukey’s tests were used to detect fracture strength differences among groups, while Chisquare test was used to check differences in fracture pattern. Results: No significant differences were observed between control group (intact teeth) and groups A1 (p = 0.999), B1 (p = 0.997) and C1 (p = 1.000); statistically significant differences were detected between control group and groups A2 (p < 0.001), B2 (p < 0.001) and C2 (p < 0.05). Different post placement techniques were non-significantly associated with fracture pattern in both groups 1 (p = 0.666) and 2 (p = 0.143) while, irrespective of the number of posts, the presence of the post was significantly associated with the fracture pattern in teeth with two residual walls. The double-post technique did not further improve the fracture resistance of hardly damaged endodontically treated maxillary bi-rooted premolars compared to single-post technique. Therefore, the insertion of a single post in the palatal canal could be a safer and more conservative choice. Clinical significance: The double-post technique did not further improve the fracture resistance of severely structurally compromised endodontically treated maxillary premolars with two roots compared to the single-post technique. Therefore, the safer and less invasive treatment is the placement of a single post in the palatal canal

Estudo multicêntrico de avaliação perioperatória para operações não cardíacas (EMAPO)

INTRODUCTION: The accuracy of perioperative evaluation methods available is better than chance, but their performance is not ideal. OBJECTIVES: To compare a new evaluation method (EMAPO) to the American College of Physicians method for determining the risk of cardiovascular complications in noncardiac surgeries and to look for new influencing variables. METHODS: Evaluations through EMAPO and the American College of Physicians method were employed for 700 patients. Cardiac events and deaths were recorded, the risk variables related to the occurrence of complications were verified, and the models were compared by analyzing the areas under the receiver operating characteristic curves. RESULTS: Mortality rate was 3.4%, and the incidence of cardiovascular complications was 5.3%. Renal failure (P = 0.01), major surgery (P = 0.004), and emergency surgery (P = 0.003) were independently related to the occurrence of cardiovascular complications. The two methods produced similar results. CONCLUSION: EMAPO is as good as the American College of Physicians method in determining the risk of cardiovascular complications in noncardiac surgeries. New variables related to surgical risk were identified.INTRODUÇÃO: A precisão dos métodos de avaliação perioperatória disponíveis é melhor que o acaso, porém está longe do ideal. OBJETIVOS: Comparar um novo método de avaliação perioperatória (EMAPO) ao método do American College of Physicians para determinar o risco cardíaco em cirurgias não cardíacas e buscar novas variáveis envolvidas na determinação deste risco. MÉTODOS: O EMAPO e o método do American College of Physicians foram aplicados em 700 pacientes. A ocorrência de eventos cardíacos e de mortes foi documentada, a relação entre as variáveis de risco e as complicações foi estabelecida e os métodos foram comparados analisando as áreas sob a curva ROC. RESULTADOS: A mortalidade foi 3.4% e a incidência de complicações cardiovasculares 5.3%. A presença de insuficiência renal (p=0.01), cirurgia de grande porte (p=0.004) e cirurgia de emergência (p=0.003) se correlacionaram com a ocorrência de complicações cardiovasculares na análise multivariada. Não houve diferença entre os dois métodos. CONCLUSÕES: O EMAPO é tão eficaz quanto o método do American College of Physicians para determinar o risco de complicações cardiovasculares em cirurgias não cardíacas. Novas variáveis relacionadas com o risco perioperatório foram encontradas

Comparison of the surface tension of 5.25% sodium hypochlorite solution with three new sodium hypochlorite-based endodontic irrigants

Aim To investigate the surface tension characteristics of 5.25% sodium hypochlorite and three recently introduced sodium hypochlorite solutions, which had been modified to reduce their surface tension: ChlorXtra, Hypoclean A and Hypoclean B. Methodology Freshly produced MilliQ water was used as a reference liquid. All measurements of surface tension were taken by the Wilhelmy plate technique, using a Cahn DCA-322 Dynamic Contact Angle Analyzer at the temperature of 22°C. A glow-discharge cleaned glass slide was immersed in 5 mL of the test liquid in a beaker cleaned with hot chromic acid, rinsed with MilliQ water and finally air plasma-cleaned in a glow-discharge reactor. The force on the glass slide was recorded continuously by the instrument software as the beaker was raised and withdrawn at the constant speed of 40 micron/s, until at least 1 cm of the glass slide was immersed. The typical accuracy was 0.5 mJ m ) had the highest surface tension values (P < 0.01) compared to ChlorXtra (33.14 mJ m ). Hypoclean A had the lowest surface tension (P < 0.01). Conclusions The new 5.25% sodium hypochlorite solutions modified with surfactants, Hypoclean A and Hypoclean B, had surface tension values that were significantly lower (P < 0.01) than Chlor-Xtra and 5.25% NaOCl. Because of their low surface tension and increased contact with dentinal walls, these new irrigants have the potential to penetrate more readily into uninstrumented areas of root canal system as well as allow a more rapid exchange with fresh solution, enabling greater antimicrobial effectiveness and enhanced pulp tissue dissolution ability

In vivo and in vitro permeability of one-step self-etch adhesives

Adhesive dentistry should effectively restore the peripheral seal of dentin after enamel removal. We hypothesize that non-rinsing, simplified, one-step self-etch adhesives are effective for minimizing dentin permeability after tooth preparation procedures. Crown preparations in vital human teeth were sealed with Adper Prompt, Xeno III, iBond, or One-Up Bond F. Epoxy resin replicas were produced from polyvinyl siloxane impressions for SEM examination. Dentin surfaces from extracted human teeth were bonded with these adhesives and connected to a fluid-transport model for permeability measurements and TEM examination. Dentinal fluid droplets were observed from adhesive surfaces in resin replicas of in vivo specimens. In vitro fluid conductance of dentin bonded with one-step self-etch adhesives was either similar to or greater than that of smear-layer-covered dentin. TEM revealed water trees within the adhesives that facilitate water movement across the polymerized, highly permeable adhesives. Both in vitro and in vivo results did not support the proposed hypothesis.published_or_final_versio

Influence of different scanning techniques on in vitro performance of CAD-CAM-fabricated fiber posts

This study assessed push-out strength, cement layer thickness, and interfacial nanoleakage of luted fiber posts fabricated with computer-aided design/computer-assisted manufacture (CAD/CAM) technology after use of 1 of 3 scanning techniques, namely, direct scanning of the post space (DS), scanning of a polyether impression of the post space (IS), and scanning of a plaster model of the post space (MS). Thirty premolars were randomly assigned to three groups corresponding to the scanning technique. Posts were computer-designed and milled from experimental fiber-reinforced composite blocks. The mean (±SD) values for push-out strength and cement thickness were 17.1 ± 7.7 MPa and 162 ± 24 μm, respectively, for DS, 10.7 ± 4.6 MPa and 187 ± 50 μm for IS, and 12.0 ± 7.2 MPa and 258 ± 78 μm for MS specimens. Median (interquartile range) interfacial nanoleakage scores were 3 (2-4) for DS, 2.5 (2-4) for IS, and 3 (2-4) for MS. Post retention was better for fiber posts fabricated by DS technique than for those fabricated by IS and MS. Cement thickness did not differ between DS and IS specimens, but the cement layer was significantly thicker in the MS group than in the other two groups. Scanning technique did not affect sealing ability, as the three groups had comparable nanoleakage values

Degradation behavior of Ti-Nb alloys: Corrosion behavior through 21 days of immersion and tribocorrosion behavior against alumina

Non-toxic and allergic free beta-type Ti alloys are attractive metallic implant materials due to their lower Young's modulus and good biocompatibility, but the corrosion and tribocorrosion behavior are yet to be fully understood. In this study, corrosion behavior of Ti-15Nb and Ti-40Nb alloys was investigated and compared with the commercial Ti-6Al-4V alloy through an immersion period of 21 days. The tribocorrosion behavior was investigated under open-circuit potential by using a ball-on-plate tribometer. Results suggested that the beta-type Ti-40Nb alloy having 51 GPa Young's modulus had lower corrosion and wear resistance as compared to the alpha + beta-type Ti-15Nb and Ti-6Al-4V alloys.This work is supported by FCTwith the reference project UID/EEA/04436/2019 and M-ERA-NET/0001/2015 (FAPESP proc. #2015/50.280-5), CNPq (307.279/2013-8) and FAPESP (2015/09.480-0). The authors would also like to acknowledge Prof. Graca Minas for the provision of the profilometry. I. Caha is grateful for financial support through PhD grant under NORTE-08-5369-FSE-000012 project