The Effect of Colloidal Silica and Glaze Coatings on the Adhesion of Zirconia with Various Ytrria Concentration.

PURPOSE: This study evaluated the effect of coating traditional and translucent Y-TZP with an industrial nanometric colloidal silica or glaze before or after sintering on the adhesion of zirconia with various ytrria concentration. MATERIALS AND METHODS: Specimens of Y-TZP with 3% and 5% yttria were subdivided into 5 groups (n=10), according to the coating applied and moment of application (before or after Y-TZP sintering): Control (no coating), Colloidal Silica/Sintering, Sintering/Colloidal Silica, Glaze/Sintering, Sintering/ Glaze. Lithium disilicate (LD) was used as positive control. Except for Y-TZP controls, groups were conditioned with silane before cementation with a self-adhesive resin cement. After 24 hours, the shear bond strength and failure analysis were performed. Also, analysis of specimens' surface was accomplished with SEM-EDX. Kruskal-Wallis and Dunn tests were applied to analyze differences between groups (p⟨0.05). RESULTS: Overall, the worst and best values of shear bond strength test were control and glaze after sintering groups. Different morphological and chemical aspects were observed in SEM-EDX analysis. CONCLUSIONS: Coating Y-TZP with colloidal silica showed unsatisfactory results. In 3Y-TZP, the surface treatment associated with the best adhesion values was the application of glaze after zirconia sintering. However, in 5Y-TZP, glaze application can be performed before or after the zirconia sintering to optimize clinical steps.

Biotechnological potential of an exo-polygalacturonase of the new strain Penicillium janthinellum VI2R3M: biochemical characterization and clarification of fruit juices.

AIMS: The aim of this work was to characterize and apply a polygalacturonase of Penicillium janthinellum new strain VI2R3M. METHODS AND RESULTS: The polygalacturonase obtained from P. janthinellum VI2R3M was incubated in cultures of passion fruit peel and was partially purified by ion-exchange chromatography and gel filtration. The enzyme showed a relative molecular mass of 102·0 kDa, maximum activity at pH 5·0, temperature of 50°C, 100% stablity at 50°C and 80% stablity at pH 3·0-5·0. The apparent Km , Vmax and Kcat values for hydrolyzing polygalacturonic acid were 2·56 mg ml-1 , 163·1 U mg-1 and 277 s-1 respectively. The polygalacturonase presented exo activity and was activated by Mg2+ . The juices treated with polygalacturonase presented increases in transmittance with reduction in colour. CONCLUSIONS: The results suggest that the new lineage P. janthinellum VI2R3M presents a high yield of an exo-polygalacturonase induced by agro-industrial residues, with excellent activity and stability in acidic pH and at 50°C. SIGNIFICANCE AND IMPACT OF THE STUDY: The use of agro-industrial residue to obtain the polygalacturonase can contribute to a decrease enzyme production cost. The results of the activity, stability to acidic pH and excellent performance in the clarification of juices show that the enzyme is promising for industrial application.

Resistance to vertical root fracture of root filled teeth using different conceptual approaches to canal preparation.

AIM: To evaluate the resistance to vertical root fracture of root filled teeth using different root canal preparation concepts: apical stop and continuously tapering preparation, with different foraminal enlargement. In addition, the effect of filling associated with these different concepts was assessed. METHODOLOGY: Ninety single-rooted premolars were used. The crowns were removed to standardize the root length at 11 mm. Ten roots were not instrumented and not filled (control group). The other roots were divided into four groups (n = 20): apical stop to finishing file size 25, 0.08 taper; apical stop to finishing file size 45, 0.02 taper; continuously tapering preparation to finishing file size 25, 0.08 taper; and continuously tapering preparation to finishing file size 45, 0.02 taper. Afterwards, 10 roots of each group were root filled using Gutta-percha and AH Plus. A continuous wave of condensation was used as the filling technique. The roots were evaluated as regards resistance to vertical fracture using a universal testing machine. The data were evaluated using the Kruskal-Wallis and Mann-Whitney tests. RESULTS: No significant difference in performance was observed between continuously tapering preparation size 25, 0.08 taper and apical stop size 45, 0.02 taper groups. Lower resistance values were found in continuously tapering preparation size 45, 0.02 taper group and the highest in apical stop size 25, 0.08 taper group. After filling, a significant increase in resistance values was observed in all groups. In addition, the continuously tapering preparation size 45, 0.02 taper group had values comparable with those of the control. CONCLUSION: The different canal preparation techniques reduced resistance to fracture when compared with the control group; however, after root filling, there was a significant increase in resistance.

Beneficial Effects of Ischemic Preconditioning in Resistance Exercise Fade Over Time.

This study evaluated the effect of ischemic preconditioning (IPC) on resistance exercise performance in upper limbs. After 12-RM load determination, 21 men attended 4 trials separated by 3 days in a randomized crossover design: IPC (4×5-min occlusion 220 mmHg/reperfusion 0 mmHg) in arms and in thighs, and SHAM (equal to the IPC protocol but "occlusion" at 20 mmHg) in arms and in thighs. 8 min following the respective interventions, the subjects performed one set of resistance exercise in elbow flexion with the 12-RM load until concentric failure. The number of repetitions increased for both protocols in arm (IPC=14.1±2.5 and SHAM=14.4±3.0) and in thigh (IPC=14.3±2.2 and SHAM=13.4±1.7). However, the number of repetitions tended to decrease over the 4 trials and no more effect was found in the fourth trial. Therefore, IPC or SHAM may enhance performance in resistance exercise for upper limbs, but this effect apparently fades over time.

Adhesion of resin-based sealers to dentine: an atomic force microscopy study.

AIM: To evaluate the effect of several final irrigants on the adhesion force (Fad) between dentine and resin-based sealers by means of atomic force microscopy (AFM). METHODOLOGY: Twelve distal roots of mandibular molars were used. The roots were smoothened and cut to obtain 36 specimens. During chemomechanical preparation of the root canals, 5.25% NaOCl was used as the irrigant. The specimens were then divided into six groups according to the final irrigant used: control group - immersed in distilled water (DW) for 1 min; chlorhexidine (CHX) group - in 2% CHX for 1 min; NaOCl group - in 5.25% NaOCl for 1 min; EDTA group - in 17% EDTA for 5 min, EDTA/CHX group - in EDTA, followed by intermediate flushing with DW and then immersed in CHX; EDTA/NaOCl group - in EDTA, followed by intermediate flushing with DW and then immersed in NaOCl. After the treatments, all groups were washed with DW to remove all traces of the irrigants. Afterwards, the samples were dried and attached to a glass base. AFM tips containing AH Plus and Real Seal SE sealers were used to obtain force-distance curves with regard to dentine-treated surfaces. Data were analysed statistically using nonparametric tests with the significance level set at P < 0.05. RESULTS: In the groups with smear layer, a final flush with CHX and NaOCl resulted in significantly higher Fad values than the control group for both sealers (P < 0.001). When smear layer was removed, the highest Fad values associated with AH Plus occurred with a final flush of NaOCl, whilst in Real Seal SE, the highest values were found with a final flush of CHX (all results significant at P < 0.001). CONCLUSION: Irrigants had a positive effect on the adhesion of the resin-based sealers, AH Plus and Real Seal SE, to dentine.

Mechanical properties of asphalt binders evaluated by atomic force microscopy.

Atomic Force Microscopy was employed in order to relate the features observed on the surface of a 50/70 asphalt binder according to its local stiffness and elastic recovery. Indentations were performed in different points of the surface and a significant variation of elasticity was observed between the points on the so-called bee structure and the matrix. Also, indentations varying the maximum force were performed on similar white spots in the bee structure and the recovery was followed up to 1 h after indentation. It was observed that the elastic recovery is very much dependent on the colloidal structure of the bee. The final surface state of the binder, close to the bee for usual bees is not the same as the initial one indicating severe plastic deformation. Also, permanent phase change could be observed for bright spots presented in not well-structured bee arrangements. A surface hardening was observed in the bee region.

Acute effect of resistance training volume on hormonal responses in trained men.

AIM: The purpose of this study was to investigate the acute hormonal response to resistance training sessions with different volumes in men. METHODS: Ten recreationally trained men (24.5±7.6 years; 76.2±9.2 kg; 175.6±1.5 cm; 24.5±5.5 kg/m(-2)) participated in the study. All subjects completed two experimental protocols with different volumes. The first protocol consisted of 3 sets at 80% of 6 RM and the second protocol was 3 sets at 80% of 12 RM with 2 minutes rest between sets and exercises, separated by seven days between them. The exercise order used was: barbell bench press, leg press, machine front lat-pull down, leg curl, shoulder abduction and leg extension. The blood variables analyzed were: testosterone, growth hormone (GH), cortisol and testosterone/cortisol ratio (T:C) before (Pre) and immediately after (Post) each exercise session. RESULTS: The intra-groups comparison for testosterone and hGH revealed a significant increase in 80%-6RM and 80%-12RM. Cortisol levels was significantly higher in 80%-12RM and T:C ratio in 80% 6 RM when compared Pre and Post values. Inter-groups comparison showed higher hGH and cortisol levels and lower T:C ratio for 80% 12 RM. There was no statistically significant different between 80%-6RM and 80%-12RM for testosterone. CONCLUSION: The present study confirms that the volume of resistance training can be an important factor in the modulation of acute hormonal responses.

High temperature AFM study of CAP 30/45 pen grade bitumen.

Bitumen is a complex mixture of hydrocarbons for which microstructural understanding is incomplete. In an effort to detail this microstructure, a asphalt cement sample (CAP 30/45) was analysed by thermal phase detection atomic force microscopy. Phase contrast and topography images showed that sample morphology is highly dependent on temperature. The 'bee structure' changed considerably at temperatures between 50 degrees C and 56 degrees C. A decrease of the oscillation amplitude was observed upon heating and the 'bees' completely disappeared at temperatures above 57 degrees C. When the temperature was decreased after melting at 170 degrees C, the 'bees' began to nucleate gradually at temperatures of 57 degrees C and its evolution with time was followed. Changes in morphology were compared to thermal analysis results and a model for the 'bee' structure was proposed.

Effects of resistance training on cytokines.

It is speculated that exercise training decreases resting levels of tumor necrosis factor alpha (TNF-alpha) and C-reactive protein (CRP); reduces body mass and leptin (LP); and increases adiponectin (AD) and insulin sensitivity. This systematic review analyzed the effectiveness of resistance training (RT) longitudinal clinical studies on AD, LP, CRP and TNF-alpha. Seventeen studies were included and the majority of randomized controlled trials support that RT produces increases in AD, and decreases in both LP and CRP. Greater responses in AD and LP were evident in overweight and obese individuals; while RT appeared to be effective in reducing CRP in obese individuals, and older adults. Additionally, women may be more responsive to RT effects on AD, LP and CRP. Training duration and intensity may affect the response of AD and CRP with greater responses shown with 16 weeks or more of training and/or with intensities greater than 80% of one repetition maximum. No response to RT of TNF-alpha levels was apparent. Although based on a limited number of studies, some of which are uncontrolled non-randomized in design, our review suggests some positive effects of RT programs on cytokine levels, but specifics of the responses in different populations need further elucidation.

Effects of chelating agent and acids on Biodentine.

BACKGROUND: To evaluate the effect of distilled water, ethylenediaminetetraacetic acid (EDTA), phosphoric acid and maleic acid on Biodentine regarding surface topography, microhardness and push-out bond strength (POBS). METHODS: Fifty-two cylindrical shaped Biodentine specimens were divided into groups: control (distilled water); EDTA (17% EDTA); PA (37% phosphoric acid); and MA (7% maleic acid). Surfaces were evaluated by topographic analysis and Vickers microhardness test. Topographic changes were evaluated qualitatively and microhardness was statistically analyzed by Kruskal-Wallis test. Forty mandibular molars were used to simulate clinical conditions. The crowns were removed and a perforation was created at the furcal floor. The Biodentine was packed into the root perforations and the roots were divided into four groups (DW, EDTA, PA, MA). Samples were stored and subjected to interfacial analysis. POBS data were analyzed by Kruskal-Wallis and Dunn tests. RESULTS: Ethylenediaminetetraacetic acid, MA and PA changed the morphology of the Biodentine surface. PA showed microhardness similar to distilled water (P > 0.05), while MA and EDTA demonstrated reduced values when compared with PA (P < 0.05). PA improved the POBS of Biodentine in comparison with the control. CONCLUSIONS: Changes in the topography, microhardness and POBS of Biodentine are associated with irrigant agent used.

Analysis of the correlation between knee extension torque and patellar tendon elastic property.

PURPOSE: Quadriceps strength and patellar tendon (PT) are directly linked and intimately related to daily activities and lower limb function. However, the correlation between knee extension torque (KT) and PT Young's modulus (E) measured directly is still unknown. METHOD: We used supersonic shearwave imaging (SSI) to evaluate the elastic property of PT in healthy young men and analysed its correlation with KT. Twenty-two healthy young males were included and both knees were examined. The E of the PT in the dominant and non-dominant legs was assessed by SSI elastography. KT in maximal voluntary isometric contraction was measured with an isokinetic dynamometer. RESULT: No correlations between KT and PT E were observed in dominant or non-dominant side (P = 0·458 and 0·126, respectively). No significant differences in KT or PT E were observed between both legs (P = 0·096 and 0·722, respectively). Intra-day ICC was rated good (D1 - 0·886, P<0·001 and 0·88, P<0·001) and excellent (D2 - 0·928, P<0·001 and 0·900, P<0·001) for both legs. Inter-day ICC was rated moderate for both legs (0·651, P = 0·016 and 0·630, P = 0·018, respectively). CONCLUSION: No significant correlations were found between KT and PT E, suggesting that quadriceps strength is not an accurate predictor for PT mechanical properties in subjects with no specific training engagement. Habitual loading pattern can play a determinant role in PT mechanical properties, regardless of quadriceps strength. Further investigation on SSI acquisition protocols should be conducted to guarantee higher inter-day ICC values.

Structure, expression, and functional analysis of the gene coding for calmodulin in the chytridiomycete Blastocladiella emersonii.

The single calmodulin (CaM) gene and the corresponding cDNA of the chytridiomycete Blastocladiella emersonii were isolated and characterized. The CaM gene is interrupted by three introns and transcribed in a single 0.7-kb mRNA species encoding a predicted protein 91% identical to human CaM. B. emersonii CaM has been expressed in Escherichia coli as a fusion protein with gluthatione S-transferase (GST) and purified by affinity chromatography and cleavage from the GST portion using a site-specific protease. In the presence of Ca(2+), B. emersonii CaM exhibited a shift in apparent molecular mass similar to that observed with bovine CaM and was able to activate the autophosphorylation of CaM-dependent protein kinase II (CaMKII) from rat brain. CaM expression is developmentally regulated in B. emersonii, with CaM mRNA and protein concentrations increasing during sporulation to maximum levels observed just prior to the release of the zoospores into the medium. Both CaM protein and mRNA levels decrease drastically at the zoospore stage, increasing again during germination. The CaM antagonists compound 48/80, calmidazolium, and W7 were shown to completely inhibit B. emersonii sporulation when added to the cultures at least 120, 150, and 180 min after induction, respectively. All these drugs also inhibited growth and zoospore production in this fungus. The Ca(2+) channel blocker TMB-8 and the CaMKII inhibitor KN93 completely inhibited sporulation if added up to 60 min after induction of this stage, but only KN93 affected fungal growth. The data presented suggest that the Ca(2+)-CaM complex and CaMKII play an important role during growth and sporulation in B. emersonii.

Further studies on the structural analysis of the cuticle of Litomosoides chagasfilhoi (Nematoda: Filarioidea).

In order to obtain further information on the structural organization of the cuticle of nematodes, this structure was isolated from adult forms of the filariid Litomosoides chagasfilhoi. The purity of the fraction was determined by light and transmission electron microscopy, deep-etching, high resolution scanning electron microscopy, atomic force microscopy, immunocytochemistry, gel electrophoresis (SDS-PAGE) and Western blot. The epicuticle presented a rugous surface with parallel rows and several globular particles that could be involved in the absorption of nutrients and secretion of products. Analysis by SDS-PAGE of purified cuticles revealed five major polypeptides corresponding to 151, 41, 28, 13 and 11 kDa. A polyclonal antibody against a synthetic 18 amino-acid peptide that corresponds to the sequence of domain E of the Haemonchus contortus3A3 collagen gene recognized several protein bands on the Western blot of purified cuticle, and labeled all cuticular layers, as shown by immunocytochemistry.