613 research outputs found

    Clinical reliability of complete-arch fixed prostheses supported by narrow-diameter implants to support complete-arch restorations

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    The aim of this study was to evaluate the clinical application of fixed screw-retained complete-arch rehabilitations supported by four narrow-diameter implants (NDIs). The records of patients treated with complete-arch prostheses screwed onto four NDIs treated with an immediate loading protocol between 2010 and 2020 with at least 1 year of follow-up after the positioning of the definitive restoration were reviewed. The implants were placed according to the final prosthetic design and were immediately loaded. The interim prostheses were replaced after the healing period by definitive acrylic resin titanium-supported prostheses. Patients were followed to evaluate treatment success, the implant survival rate (ISR), and the prosthetic survival rate (PSR). A total of 121 NDIs were positioned in 30 patients to restore 30 complete arches (18 maxilla and 12 mandible). One implant did not achieve osseointegration, resulting in an overall ISR of 99.2%. No prosthetic or implant failures occurred during the 1 to 11 years of follow-up. Three biological and four prosthetic complications occurred, resulting in a treatment rehabilitation survival of 94.1% and a PSR of 86.7%. Despite the limitations of the present retrospective study, such as the use of one single type of dental implant and patients treated in a single rehabilitation center, complete-arch rehabilitation with fixed prostheses supported by four NDIs seems to be a reliable treatment in the medium to long term

    Clinical Reliability of Complete-Arch Fixed Prostheses Supported by Narrow-Diameter Implants to Support Complete-Arch Restorations

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    The aim of this study was to evaluate the clinical application of fixed screw-retained complete-arch rehabilitations supported by four narrow-diameter implants (NDIs). The records of patients treated with complete-arch prostheses screwed onto four NDIs treated with an immediate loading protocol between 2010 and 2020 with at least 1 year of follow-up after the positioning of the definitive restoration were reviewed. The implants were placed according to the final prosthetic design and were immediately loaded. The interim prostheses were replaced after the healing period by definitive acrylic resin titanium-supported prostheses. Patients were followed to evaluate treatment success, the implant survival rate (ISR), and the prosthetic survival rate (PSR). A total of 121 NDIs were positioned in 30 patients to restore 30 complete arches (18 maxilla and 12 mandible). One implant did not achieve osseointegration, resulting in an overall ISR of 99.2%. No prosthetic or implant failures occurred during the 1 to 11 years of follow-up. Three biological and four prosthetic complications occurred, resulting in a treatment rehabilitation survival of 94.1% and a PSR of 86.7%. Despite the limitations of the present retrospective study, such as the use of one single type of dental implant and patients treated in a single rehabilitation center, complete-arch rehabilitation with fixed prostheses supported by four NDIs seems to be a reliable treatment in the medium to long term

    \u201cWoulda, coulda, shoulda\u201d. Workers\u2019 proactivity in the association between emotional demands and mental health

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    The present study aimed to explore the mediating role of hostile customer relations in the association between emotional dissonance and workers\u2019 mental health. Moreover, the moderating role of proactive personality as a buffer against hostile customer relations was assessed. Emotional demands become crucial within professions that involve a direct relationship with clients and, if poorly managed, can negatively affect workers\u2019 health and performance. Accordingly, data were collected on a sample of n = 918 mass-retail employees working for one of the leading Italian supermarket companies. Most participants were women (62.7%) with a mean age = 40.38 (SD = 7.68). The results of a moderated mediation analysis revealed that emotional dissonance was related to more hostile customer relations that, in turn, were associated with higher rates of mental health symptoms. Proactive personality emerged as a protecting factor that prevented the onset of conflicts with clients, particularly among workers experiencing high levels of emotional dissonance. The identification of resources enabling management of emotional demands could suggest suitable adaptive strategies for customer-facing roles, thus preventing the occurrence of adverse mental health symptoms

    Influence of parameter estimation uncertainty in Kriging: Part 2 - Test and case study applications

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    The theoretical approach introduced in Part 1 is applied to a numerical example and to the case of yearly average precipitation estimation over the Veneto Region in Italy. The proposed methodology was used to assess the effects of parameter estimation uncertainty on Kriging estimates and on their estimated error variance. The Maximum Likelihood (ML) estimator proposed in Part 1, was applied to the zero mean deviations from yearly average precipitation over the Veneto Region in Italy, obtained after the elimination of a non-linear drift with elevation. Three different semi-variogram models were used, namely the exponential, the Gaussian and the modified spherical, and the relevant biases as well as the increases in variance have been assessed. A numerical example was also conducted to demonstrate how the procedure leads to unbiased estimates of the random functions. One hundred sets of 82 observations were generated by means of the exponential model on the basis of the parameter values identified for the Veneto Region rainfall problem and taken as characterising the true underlining process. The values of parameter and the consequent cross-validation errors, were estimated from each sample. The cross-validation errors were first computed in the classical way and then corrected with the procedure derived in Part 1. Both sets, original and corrected, were then tested, by means of the Likelihood ratio test, against the null hypothesis of deriving from a zero mean process with unknown covariance. The results of the experiment clearly show the effectiveness of the proposed approach. Keywords: yearly rainfall, maximum likelihood, Kriging, parameter estimation uncertaint

    Depression of early phase of HTLV-I infection in vitro mediated by human beta-interferon.

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    Natural human interferon beta (beta-IFN) was tested during the early phase of in vitro infection with HTLV-I virus of human cord blood mononuclear cells (CBL), to evaluate whether its antiviral and immunomodulating effects might prevent spreading of infection in the host. beta-IFN was found to reduce HTLV-I transmission and integration in CBL cultures. Moreover, beta-IFN had no effect in preventing virus transmission and integration in K562 and a very limited effect in HL60 and Molt-4 human tumour lines, suggesting a cell-type specific mode of action. beta-IFN induced a 'priming' response on CBL, since overnight pretreatment of recipient cells or one single treatment at the onset of the coculture were almost equally effective in protecting against HTLV-I infection. During the early days post infection (p.i.), IFN-treated CBL showed a pattern of phenotypic markers that was closer to that of non-infected CBL. In contrast, untreated CBL exposed to HTLV-I showed a percent increase of Tac+, M3+ and Leu 11+ subpopulations. Cell-mediated immune responses of CBL were depressed after coculturing with HTLV-I producer MT-2 cells. beta-IFN was able to boost the cell-mediated cytotoxicity of fresh and infected CBL against both K562 and MT-2 target cells. Leukocyte blastogenesis in mixed lymphocyte/tumour cell cultures, evaluated in terms of 3H-thymidine incorporation during the first week p.i., was also enhanced by IFN when macrophages and lymphocytes were reconstituted at an optimal 1:20 ratio. It is conceivable that this overall enhancement of the immune response induced by beta-IFN could contribute to reduce HTLV-I infection in vitro

    Hemispheric Asymmetry of Globus Pallidus Explains Reward-related Posterior Alpha Modulation in Humans

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    While subcortical structures such as the basal ganglia (BG) have been widely explored in relation to motor control, recent evidence suggests that their mechanisms extend to the domain of attentional switching. We here investigated the subcortical involvement in reward related top-down control of visual alpha-band oscillations (8 – 13 Hz), which have been consistently linked to the mechanisms supporting the allocation of visual spatial attention. Given that items associated with contextual saliency (e.g. monetary reward or loss) attract attention, it is not surprising that alpha oscillations are further modulated by the saliency properties of the visual items. The executive network controlling such reward-dependent modulations of oscillatory brain activity has yet to be fully elucidated. Although such network has been explored in terms of cortico-cortical interaction, it likely relies also on the contribution of subcortical regions. To uncover this, we investigated whether derived measures of subcortical structural asymmetries could predict interhemispheric modulation of alpha power during a spatial attention task. We show that volumetric hemispheric lateralization of globus pallidus (GP) and thalamus (Th) explains individual hemispheric biases in the ability to modulate posterior alpha power. Importantly, for the GP, this effect became stronger when the value-saliency parings in the task increased. Our findings suggest that the Th and GP in humans are part of a subcortical executive control network, differently involved in modulating posterior alpha activity. Further investigation aimed at uncovering the interaction between subcortical and neocortical attentional networks would provide useful insight in future studies

    Dual stage resistive transition of MgB2 evidenced by noise analysis

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    The resistive transition of polycrystalline superconducting MgB2 films is studied by means of an extensive set of stationary noise measurements, going from the very beginning of the transition to its final point, where the normal state is reached, either with and without magnetic field. The experimental results, taken at low current density and close to the critical temperature Tc, show very clearly the existence of two different dissipative processes at the different stages of the transition. An extended analysis proves that, at the beginning of the transition, when the resistance is below ten percent of normal value, the specimen is in a mixed state and dissipation is produced by fluxoid creation and motion. At higher temperature the specimen is in an intermediate state, constituted by a structure of interleaved superconducting and resistive domains. Such a situation occurs in type II superconductor when the transition temperature is very near to Tc and the critical field Hc for fluxoid penetration tends to zero. It is found that in the intermediate state, the power spectrum of the relative resistance fluctuations, is independent of the average resistance value and is unaffected by the magnetic field. As shown in the paper, this means that the noise is generated by density fluctuation of the normal electron gas in the resistive domains, while the contribution of the superconducting ones is negligible. The reduced noise amplitude does not depend on the steepness of the transition curve, thus adding further evidence to the above interpretation. The noise is thus related to the film impurities and can be investigated when the specimen is in the normal state, even at room temperature. The occurrence of a different dissipative process at low resistance is clearly evidenced by the experimental results, which show that the amplitude of the reduced power spectrum of the noise depends on magnetic field and resistance. These results are consistent with the assumption of fluxoid noise as shown by the model for the calculation of the noise developed in the manuscrip

    Influence of Xpand Nitric Oxide Reactor, L-Arginine Alpha-Ketoglutarate, and Caffeine Supplementation on Calf Muscle Re-Oxygenation During and after Acute Resistance Exercise

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    Xpand Nitric Oxide Reactor is a "cocktail" supplement proposed to improve skeletal muscle blood flow via arginine's effect on nitric oxide synthesis and vasodilation. Two other major ingredients, caffeine and creatine, cause vasoconstriction, which could potentially counteract the proposed hemodynamic effects of arginine. The purpose of this study was to examine the influence of Xpand Nitric Oxide Reactor on muscle re-oxygenation after resistance exercise compared to supplementation with constituent ingredients L-arginine alpha-ketoglutarate and caffeine. Nine recreationally active men (21±1y) performed 3 sets of 20 repetitions of seated single-leg calf raise at 60% 1-RM with 3 min rests. The same calf raise exercise was performed following 4 separate supplementation conditions: L-arginine alpha-ketoglutarate (AAKG), caffeine (CAFF), Xpand Nitric Oxide Reactor (XPAND), and placebo (PLAC). Soleus muscle re-oxygenation time was measured before, during, and immediately after exercise using near infrared spectroscopy. Supplementation with XPAND (0.43±0.03), AAKG (0.34±0.02), and CAFF (0.45±0.05) did not significantly affect muscle re-oxygenation halftime (minutes) compared to placebo (0.35±0.04). An arginine containing "cocktail" supplement did not affect skeletal muscle re-oxygenation after resistance exercise, possibly due to a wash-out effect caused by the multiple ingredients
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