254 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

    There is a limit to your openness: Mental illness stigma mediates effects of individual traits on preference for psychiatry specialty

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    Objective: The widening gap between the need for mental health professionals and the low percentages of medical students pursuing a psychiatric career urges an examination of how individual traits, stigma attitudes, and related intended behaviors interact to better explain the variance in preferences for psychiatry as a specialty choice. Methods: Participants were second-year, preclinical medical students at Bologna University, Italy. The study consisted in completion of an online questionnaire evaluating preferences for the psychiatry specialty (one single item and a scenario-based response), personality traits (the Big Five Questionnaire), attitudes (Mental Illness for Clinicians\u2019 Attitude scale), behaviors (Reported and Intended Behavior Scale), and fears toward mental illness (questionnaire created ad hoc). Sociodemographic data were also collected. Results: A total of 284 medical students [58.8% female, mean (SD) age 20.47 \ub1 1.90] completed the questionnaire. Preference for the psychiatry specialty was significantly and positively associated with openness to experience and negatively related with Mental Illness for Clinicians\u2019 Attitude scale and Reported and Intended Behavior Scale. The full-mediation model provided good indices explaining 18% of the variance. Mental illness stigma was strongly and negatively associated with both openness to experience and preference for psychiatry, and the mediation results evidenced a positive and significant effect. Conclusions: Mental illness stigma influences medical students\u2019 choice of psychiatry as a specialty, accounting for the effects of the openness to experience trait. Stigma awareness and reduction programs should be introduced as early as possible in medical education

    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

    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

    Radiomics to predict response to neoadjuvant chemotherapy in rectal cancer: influence of simultaneous feature selection and classifier optimization

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    According to the guidelines, patients with locally advanced colorectal cancer undergo neoadjuvant chemotherapy. However, response to therapy is reached only up to 30% of cases. Therefore, it would be important to predict response to therapy before treatment. In this study, we demonstrated that the simultaneous optimization of feature subset and classifier parameters on different imaging datasets (T2w, DWI and PET) could improve classification performance. On a dataset of 51 patients (21 responders, 30 non responders), we obtained an accuracy of 90%, 84% and 76% using three optimized SVM classifiers fed with selected features from PET, T2w and ADC images, respectively

    Deep learning to segment liver metastases on CT images: Impact on a radiomics method to predict response to chemotherapy

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    Predicting response to neo-adjuvant chemotherapy of liver metastases (mts) using CT images is of key importance to provide personalized treatments. However, manual segmentation of mts should be avoid to develop methods that could be integrated into the clinical practice. The aim of this study is to evaluate if and how much automatic segmentation can affect a radiomics-based method to predict response to neoadjuvant chemotherapy of individual liver mts. To this scope, we developed an automatic deep learning method to segment liver mts, based on the U-net architecture, and we compared the classification results of a classifier fed with manual and automatic masks. In the validation set composed of 39 liver mts, the automatic deeplearning algorithm was able to detect 82% of mts, with a median precision of 67%. Using manual and automatic masks, we obtained the same classification in 19/32 mts. In case of mts with largest diameter > 20 mm, the precision of the segmentation does not impact the classification results and we obtained the same classification with both masks. Conversely, with smaller mts, we showed that a Dice coefficient of at least 0.5 should be obtained to extract the same information from the two segmentations. This are very important results in the perspective of using radiomics-based approach to predict response to therapy into clinical practice. Indeed, either precisely manually segment all lesions or refine them after automatic segmentation is a time-consuming task that cannot be performed on a daily basis

    A Prostate Cancer Computer Aided Diagnosis Software including Malignancy Tumor Probabilistic Classification

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    Prostate Cancer (PCa) is the most common solid neoplasm in males and a major cause of cancer-related death. Screening based on Prostate Specific Antigen (PSA) reduces the rate of death by 31%, but it is associated with a high risk of over-diagnosis and over-treatment. Prostate Magnetic Resonance Imaging (MRI) has the potential to improve the specificity of PSA-based screening scenarios as a non-invasive detection tool. Research community effort focused on classification techniques based on MRI in order to produce a malignancy likelihood map. The paper describes the prototyping design, the implemented work-flow and the software architecture of a Computer Aided Diagnosis (CAD) software which aims at providing a comprehensive diagnostic tool, including an integrated classification stack, from a preliminary registration of images to the classification process. This software can improve the diagnostic accuracy of the radiologist, reduce reader variability and speed up the whole diagnostic work-up

    Lattice calculation of the Ds meson radiative form factors over the full kinematical range

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    We compute the structure-dependent axial and vector form factors for the radiative leptonic decays Ds→ℓνℓγ, where ℓ is a charged lepton, as functions of the energy of the photon in the rest frame of the Ds meson. We work in the electroquenched approximation, using gauge-field configurations with 2+1+1 sea-quark flavors generated by the European Twisted Mass Collaboration and the results have been extrapolated to the continuum limit. For the vector form factor we observe a very significant partial cancellation between the contributions from the emission of the photon from the strange quark and that from the charm quark. The results for the form factors are used to test the reliability of various Anzätze based on single-pole dominance and its extensions, and we present a simple parametrization of the form factors which fits our data very well and which can be used in future phenomenological analyses. Using the form factors we compute the differential decay rate and the branching ratio for the process Ds→eνeγ as a function of the lower cutoff on the photon energy. With a cutoff of 10 MeV for example, we find a branching ratio of Br(Eγ>10  MeV)=4.4(3)×10-6 which, unlike some model calculations, is consistent with the upper bound from the BESIII experiment Br(Eγ>10  MeV)<1.3×10-4 at 90% confidence level. Even for photon energies as low as 10 MeV, the decay Ds→eνeγ is dominated by the structure-dependent contribution to the amplitude (unlike the decays with ℓ=μ or τ), confirming its value in searches for hypothetical new physics as well as in determining the Cabibbo-Kobayashi-Maskawa parameters at O(αem), where αem is the fine-structure constant

    Lattice calculation of the DsD_{s} meson radiative form factors over the full kinematical range

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    We compute the structure-dependent axial and vector form factors for the radiative leptonic decays Ds→ℓνℓγD_s\to \ell\nu_\ell\gamma, where ℓ\ell is a charged lepton, as functions of the energy of the photon in the rest frame of the DsD_s meson. The computation is performed using gauge-field configurations with 2+1+1 sea-quark flavours generated by the European Twisted Mass Collaboration and the results have been extrapolated to the continuum limit. For the vector form factor we observe a very significant partial cancellation between the contributions from the emission of the photon from the strange quark and that from the charm quark. The results for the form factors are used to test the reliability of various Anz\"atze based on single-pole dominance and its extensions, and we present a simple parametrization of the form factors which fits our data very well and which can be used in future phenomenological analyses. Using the form factors we compute the differential decay rate and the branching ratio for the process Ds→eνeγD_s\to e\nu_e\gamma as a function of the lower cut-off on the photon energy. With a cut-off of 10 MeV for example, we find a branching ratio of Br(Eγ>10 MeV)=4.4(3)×10−6(E_\gamma>10\,\mathrm{MeV})=4.4(3)\times 10^{-6} which, unlike some model calculations, is consistent with the upper bound from the BESIII experiment Br(Eγ>10 MeV)<1.3×10−4(E_\gamma>10\,\mathrm{MeV})<1.3\times 10^{-4} at 90% confidence level. Even for photon energies as low as 10 MeV, the decay Ds→eνeγD_s\to e\nu_e\gamma is dominated by the structure-dependent contribution to the amplitude (unlike the decays with ℓ=μ\ell=\mu or τ\tau), confirming its value in searches for hypothetical new physics as well as in determining the Cabibbo-Kobayashi-Maskawa (CKM) parameters at O(αem)O(\alpha_\mathrm{em}), where αem\alpha_{\mathrm{em}} is the fine-structure constant.Comment: 31 pages, 14 figure
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