29 research outputs found
Hydrodenticity to enhance relaxivity of gadolinium-DTPA within crosslinked hyaluronic acid nanoparticles
Water-Mediated Nanostructures for Enhanced MRI: Impact of Water Dynamics on Relaxometric Properties of Gd-DTPA
Recently, rational design of a new class of contrast agents (CAs), based on biopolymers (hydrogels), have received considerable attention in Magnetic Resonance Imaging (MRI) diagnostic field. Several strategies have been adopted to improve relaxivity without chemical modification of the commercial CAs, however, understanding the MRI enhancement mechanism remains a challenge. Methods: A multidisciplinary approach is used to highlight the basic principles ruling biopolymer-CA interactions in the perspective of their influence on the relaxometric properties of the CA. Changes in polymer conformation and thermodynamic interactions of CAs and polymers in aqueous solutions are detected by isothermal titration calorimetric (ITC) measurements and later, these interactions are investigated at the molecular level using NMR to better understand the involved phenomena. Water molecular dynamics of these systems is also studied using Differential Scanning Calorimetry (DSC). To observe relaxometric properties variations, we have monitored the MRI enhancement of the examined structures over all the experiments. The study of polymer-CA solutions reveals that thermodynamic interactions between biopolymers and CAs could be used to improve MRI Gd-based CA efficiency. High-Pressure Homogenization is used to obtain nanoparticles. Results: The effect of the hydration of the hydrogel structure on the relaxometric properties, called Hydrodenticity and its application to the nanomedicine field, is exploited. The explanation of this concept takes place through several key aspects underlying biopolymer-CA's interactions mediated by the water. In addition, Hydrodenticity is applied to develop Gadolinium-based polymer nanovectors with size around 200 nm with improved MRI relaxation time (10-times). Conclusions: The experimental results indicate that the entrapment of metal chelates in hydrogel nanostructures offers a versatile platform for developing different high performing CAs for disease diagnosis
I.S.Mu.L.T. Achilles Tendon Ruptures Guidelines
This work provides easily accessible guidelines for the diagnosis, treatment and rehabilitation of Achilles tendon ruptures. These guidelines could be considered as recommendations for good clinical practice developed through a process of systematic review of the literature and expert opinion, to improve the quality of care for the individual patient and rationalize the use of resources. This work is divided into two sessions: 1) questions about hot topics; 2) answers to the questions following Evidence Based Medicine principles. Despite the frequency of the pathology andthe high level of satisfaction achieved in treatment of Achilles tendon ruptures, a global consensus is lacking. In fact, there is not a uniform treatment and rehabilitation protocol used for Achilles tendon ruptures
The role of cognitive reserve and clinical symptoms in the association between genetic liability for educational attainment and functioning in first-episode psychosis: a mediation analysis
Background: Polygenic risk scores for educational attainment (PRSEA), cognitive reserve (CR), and clinical symptoms are associated with psychosocial functioning in first-episode psychosis (FEP). Nevertheless, the mechanisms underlying their complex interaction is yet to be explored. This study aimed to assess the mediating role of CR and clinical symptoms, both negative (NS) and positive (PS), on the interrelationship between PRSEA and functionality, one year after a FEP.Methods: A total of 162 FEP patients underwent clinical, functional, and genetic assessments. Using genome-wide association study (GWAS) summary results, PRSEA were constructed for each individual. Two mediation models were explored. The parallel mediation model explored the relationship of PRSEA with functionality through CR and clinical symptoms, NS, and PS. The serial mediation model tested a causal chain of the three mediators: CR, NS and PS. Mediation analysis was performed using the PROCESS function V.4.1 in SPSS V.22.Results: A serial mediation model revealed a causal chain for PRSEA > CR > NS > Functionality (β=-0.35, 95%CI [-0.85, -0.04], pConclusions: Both CR and NS mediate the relationship between PRSEA and functionality at one-year follow-up, using serial mediation analysis. This may be relevant for prevention and personalized early intervention to reduce illness impact and improve functional outcomes in FEP patients.</p
The use of odds ratio in the large population-based studies: Warning to readers
When researchers conduct large prospective studies, they provide results generating statistical analysis; therefore readers need considerable familiarity with descriptive and inferential statistics.
If quantitative judgments are based on interpreting odds ratios as though they were relative risks, they are unlikely to be seriously in error.
Because of the calculating method, the OR is often less precise than the RR in estimating the strength of an association, and this should definitely be kept in mind by anyone who reads and interprets the results of a large population basedstud
Shallow Anterior Chamber After Trabeculectomy: Risk Reduction by Use of Removable Compression Sutures
PURPOSE::
To evaluate the risk of shallow anterior chamber after trabeculectomy with removable compression sutures.
METHODS::
A total of 263 eyes affected by primary open-angle glaucoma that was unresponsive to medical treatments were divided into 2 groups: 126 eyes were treated with conventional trabeculectomy (group A) and 137 with a modified surgery technique using 3 removable compression 10-0 nylon sutures (group B). All the participants received intraoperative antimetabolites (mitomycin 0.04%). Increased intraocular pressure (IOP) of >14 mm Hg in the eyes of group B patients was followed by removal of compression sutures. Best corrected visual acuity, slit lamp examination, IOP, and anterior chamber depth were evaluated 1, 7, 30, 60, 90, and 180 days after surgery.
RESULTS::
On the first postoperative day, 12 eyes from group A (9.5%) exhibited a shallow anterior chamber with marked hypotony and no eyes in group B showed flat anterior chamber at any control evaluation (P14 mm Hg (90%). The day after suture removal, mean IOP decreased to 10.45 mm Hg (±1.37). There was no significant statistical difference in visual acuity between the 2 groups at any point during follow-up (P>0.001). At 180 postoperative days the difference in mean IOP between the 2 groups was statistically significant (P<0.001).
CONCLUSIONS::
The application of removable corneoscleral compression sutures during trabeculectomy reduced the risk of postoperative shallow anterior chamber and allowed for safe IOP control after the procedure giving further postoperative chance to reduce the intraocular pressure
A minimal tight-binding model for the quasi-one-dimensional superconductor K2Cr3As3
We present a systematic derivation of a minimal five-band tight-binding model for the description of the electronic structure of the recently discovered quasi-one-dimensional superconductor K2Cr3As3. Taking as a reference the density-functional theory (DFT) calculation, we use the outcome of a Löwdin procedure to refine a Wannier projection and fully exploit the predominant weight at the Fermi level of the states having the same symmetry of the crystal structure. Such states are described in terms of five quasi-atomic d orbitals: four planar orbitals, two dxy and two dx2-y2, and a single out-of-plane one, d z 2 . We show that this minimal model reproduces with great accuracy the DFT band structure in a broad energy window around the Fermi energy. Moreover, we derive an explicit simplified analytical expression of such model, which includes three nearest-neighbor (NN) hopping terms along the z direction and one NN term within the xy plane. This model captures very efficiently the energy spectrum of the system and, consequently, can be used to study transport properties, super- conductivity and dynamical effects in this novel class of superconductors
Optimizing the tight-binding parametrization of the quasi-one-dimensional superconductor K2Cr3As3
We study the tight-binding dispersion of the recently discovered superconductor K2Cr3As3, obtained from Wannier projection of Density Functional Theory (DFT) results. In order to establish quantitatively the actual degree of quasi-one-dimensionality of this compound, we analyze the electronic band structure for two reduced sets of hopping parameters: one restricted to the Cr-As tubes and another one retaining a minimal number of in-plane hoppings. The corresponding total and local density of states of the compound are also computed with the aim of assessing the tight-binding results with respect to the DFT ones. We find a quite good agreement with the DFT results for the more extended set of hopping parameters, especially for what concerns the orbitals that dominate at the Fermi level. Therefore, we conclude that one cannot avoid taking into account in-plane hoppings up to the next-nearest-neighbors cells even only to describe correctly the Fermi surface cuts and the populations along the kzdirection. Such a choice of a minimal number of hopping parameters directly reflects in the possibility of correctly describing correlations and magnetic interactions