Tunable diffusion of magnetic particles in a quasi-one-dimensional channel

The diffusion of a system of ferromagnetic dipoles confined in a quasi-one-dimensional parabolic trap is studied using Brownian dynamics simulations. We show that the dynamics of the system is tunable by an in-plane external homogeneous magnetic field. For a strong applied magnetic field, we find that the mobility of the system, the exponent of diffusion and the crossover time among different diffusion regimes can be tuned by the orientation of the magnetic field. For weak magnetic fields, the exponent of diffusion in the subdiffusive regime is independent of the orientation of the external field.Comment: 9 pages, 13 figures, to appear in Phys. Rev. E (2013

Hysteresis and re-entrant melting of a self-organized system of classical particles confined in a parabolic trap

A self-organized system composed of classical particles confined in a two-dimensional parabolic trap and interacting through a potential with a short-range attractive part and long-range repulsive part is studied as function of temperature. The influence of the competition between the short-range attractive part of the inter-particle potential and its long-range repulsive part on the melting temperature is studied. Different behaviors of the melting temperature are found depending on the screening length ($\kappa$) and the strength ($B$) of the attractive part of the inter-particle potential. A re-entrant behavior and a thermal induced phase transition is observed in a small region of ($\kappa,B$)-space. A structural hysteresis effect is observed as a function of temperature and physically understood as due to the presence of a potential barrier between different configurations of the system.Comment: 8 pages, 6 figure

Evaluation of the efficacy of EU-TIRADS and ACR-TIRADS in risk stratification of pediatric patients with thyroid nodules

BACKGROUND: Pediatric thyroid nodules have a lower prevalence but a higher rate of malignancy (ROM) than those in adults. Ultrasound features suspected of malignancy lead to fine needle aspiration biopsy (FNAB) and subsequent cytological determination, upon which management is decided. Based on the characteristics of ultrasound, to standardize clinician decisions and avoid unnecessary FNAB, the European Thyroid Association and the American Radiology College have established guidelines for Thyroid Imaging, Reporting and Data System (EU-TIRADS and ACR-TIRADS) for ROM stratification of thyroid nodules. The aim of this study is to evaluate the diagnostic performance of ACR-TIRADS and EU-TIRADS in pediatric age. MATERIALS AND METHODS: Subjects younger than 18 years of age with thyroid nodules greater than 0.5 cm observed in the 2000-2020 period were included. RESULTS: Data from 200 subjects were collected. The overall ROM was 13%, rising to 26% if nodules with a diameter >1 cm were considered. Patients with a malignant nodule were more likely to have a higher EU-TIRADS score (p=0.03). Missed cancer diagnoses were 26.9%. Using the EU-TIRADS system, 40% of FNABs could have been avoided, while this scoring system would have resulted in FNAB being performed in 12% of cases where the assessment of ultrasound features would not recommend FNAB. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were 73.1%, 57.1%, 73.1%, and 50%, respectively. Even considering the ACR-TIRADS, a higher score correlated with a higher ROM (p<0.001). This system missed 6 diagnoses of cancer (23.1%). Using the ACR-TIRADS system, 45.3% of FNABs could have been avoided, while FNAB should have been performed in 12% of cases where it was not recommended by ultrasound characteristics. Sensitivity, specificity, PPV and NPV were 76.9%, 50%, 76.9%, and 42.9%, respectively. CONCLUSION: The present study confirms the correspondence of the EU-TIRADS and ACR-TIRADS categories with respect to malignancy but indicates not entirely satisfactory performance compared to FNAB alone. However, the use of the two TIRADS systems should be encouraged in multicentre studies to increase their performance and establish paediatric-specific points in the scoring criteria

Composite material comprising pectin and calcium phosphate and method for its realisation

A method for obtaining a composite material including an aqueous solution of pectin and a suspension/solution of calcium phosphate mixed together, wherein said solution of pectin cross-links with a portion of the calcium obtained from the solution of calcium phosphate and wherein a portion of the calcium phosphate in suspension remains as inorganic phase and composite materials obtained by this method

Immunological and Differentiation Properties of Amniotic Cells Are Retained After Immobilization in Pectin Gel

Mesenchymal stromal cells from the human amniotic membrane (i.e., human amniotic mesenchymal stromal cells [hAMSCs]) of term placenta are increasingly attracting attention for their applications in regenerative medicine. Osteochondral defects represent a major clinical problem with lifelong chronic pain and compromised quality of life. Great promise for osteochondral regeneration is held in hydrogel-based constructs that have a flexible composition and mimic the physiological structure of cartilage. Cell loading within a hydrogel represents an advantage for regenerative purposes, but the encapsulation steps can modify cell properties. As pectin gels have also been explored as cell vehicles on 3D scaffolds, the aim of this study was to explore the possibility to include hAMSCs in pectin gel. Immobilization of hAMSCs into pectin gels could expand their application in cell-based bioengineering strategies. hAMSCs were analyzed for their viability and recovery from the pectin gel and for their ability to differentiate toward the osteogenic lineage and to maintain their immunological characteristics. When treated with a purposely designed pectin/hydroxyapatite gel biocomposite, hAMSCs retained their ability to differentiate toward the osteogenic lineage, did not induce an immune response, and retained their ability to reduce T cell proliferation. Taken together, these results suggest that hAMSCs could be used in combination to pectin gels for the study of novel osteochondral regeneration strategies