Multiphysics Finite\u2013Element Modelling of an All\u2013Vanadium Redox Flow Battery for Stationary Energy Storage

All-Vanadium Redox Flow Batteries (VRFBs) are emerging as a novel technology for stationary energy storage. Numerical models are useful for exploring the potential performance of such devices, optimizing the structure and operating condition of cell stacks, and studying its interfacing to the electrical grid. A one-dimensional steady-state multiphysics model of a single VRFB, including mass, charge and momentum transport and conservation, and coupled to a kinetic model for electrochemical reactions, is first presented. This model is then extended, including reservoir equations, in order to simulate the VRFB charge and discharge dynamics. These multiphysics models are discretized by the finite element method in a commercial software package (COMSOL). Numerical results of both static and dynamic 1D models are compared to those from 2D models, with the same parameters, showing good agreement. This motivates the use of reduced models for a more efficient system simulation

Distributed and Lumped Parameter Models for Fuel Cells

The chapter presents a review of modeling techniques for three types of fuel cells that are gaining industrial importance, namely, polymer electrolyte membrane (PEMFC), direct methanol (DMFC), and solid oxide (SOFC) fuel cells (FCs). The models presented are both multidimensional, suitable for investigating distributions, gradients, and inhomogeneities inside the cells, and zero-dimensional, which allows for fast analyses of overall performance and can be easily interfaced with or embedded in other numerical tools, for example, for studying the interaction with static converters needed to control the electric power flow. Thermal dependence is considered in all models. Some special numerical approaches are presented, which allow facing specific problems. An example is the Proper Generalized Decomposition (PDG) that allows overcoming the challenges arising from the extreme aspect ratio of the thin electrolyte separating anode and cathode. The use of numerical modeling as part of identification techniques, particularly by means of stochastic optimization approaches, for extracting the material parameters from multiple in situ measurements is also discussed and examples are given. Merits and demerits of the different models are discussed

Lithium disilicate posterior overlays: clinical and biomechanical features

The aim of this study was to evaluate the survival rate of lithium disilicate overlays in increasing occlusal vertical dimension (OVD) in the setting of minimally invasive techniques and the restoration thicknesses at different tooth sites. This is an observational study evaluating 43 lithium disilicate overlays (Lithium IPS e.max Press, Ivoclar Vivadent) on 8 patients, prepared with minimally invasive criteria over a follow-up period between 19 to 45 months (mean follow-up of 32 months). Occlusal vertical dimension's increase was planned using occlusal treatment plan and diagnostic wax-up. Prior to adhesive cementation, restoration thicknesses were measured with a caliber. The survival rate was calculated by Kaplan-Meier analysis. Restoration survival rates at 32 months were 97.7%. One infiltration was observed, no cases of fracture occurred. The greatest thickness in monolithic restorations was detected in the cusp sides of teeth, whereas the thinnest was highlighted in the central fossa. The average amount of dental tissue removed during preparation was 0.98 mm in non-functional cusps, 0.88 mm in functional cusps, and 0.57 mm in the central fossa. Lithium disilicate posterior overlays show an excellent complication-free survival rate, and the material allows for conservative restorations with minimum thickness. Monolithic lithium disilicate overlays feature a satisfying 32-month survival rate. The technique allows to perform restorations with a minimal removal of dental tissue, while limiting fractures over time. Its esthetical performance is excellent

Clinical and Esthetical Evaluation of 79 Lithium Disilicate Multilayered Anterior Veneers with a Medium Follow-Up of 3 Years

Objectives Primary aim of this study was to evaluate survival rate of lithium disilicate veneers in upper and lower anterior teeth. Secondary aims were to evaluate changing in proportions of teeth before and after restorations and to assess mean thickness of the veneers. Materials and Methods Seventy-nine upper and lower lithium disilicate veneers were made in 13 patients with worn teeth. Mean follow-up was 3 years. To perform anterior definitive rehabilitations, malocclusions and loss of vertical dimension were treated by full mouth rehabilitations to obtain proper occlusal conditions. Veneers were made of lithium disilicate core and fluorapatite-based ceramic stratification. Survival rate was calculated by Kaplan-Meier analysis. Changing in teeth proportion before and after restorations was analyzed by a paired t -test. Descriptive statistics of thickness values were also performed. Results One case of detachment was observed with a 98.7% survival rate. Teeth's proportions were preserved although the first upper right incisor and canine changed in dimension. Conclusions Lithium disilicate veneers in esthetical rehabilitations of worn teeth proved to be an effective way of treatment in a medium follow-up of 3 years. Proportions seemed to be maintained with a minimum dental removal

Patient-Derived Xenografts of Non Small Cell Lung Cancer: Resurgence of an Old Model for Investigation of Modern Concepts of Tailored Therapy and Cancer Stem Cells

Current chemotherapy regimens have unsatisfactory results in most advanced solid tumors. It is therefore imperative to devise novel therapeutic strategies and to optimize selection of patients, identifying early those who could benefit from available treatments. Mouse models are the most valuable tool for preclinical evaluation of novel therapeutic strategies in cancer and, among them, patient-derived xenografts models (PDX) have made a recent comeback in popularity. These models, obtained by direct implants of tissue fragments in immunocompromised mice, have great potential in drug development studies because they faithfully reproduce the patient's original tumor for both immunohistochemical markers and genetic alterations as well as in terms of response to common therapeutics They also maintain the original tumor heterogeneity, allowing studies of specific cellular subpopulations, including their modulation after drug treatment. Moreover PDXs maintain at least some aspects of the human microenvironment for weeks with the complete substitution with murine stroma occurring only after 2-3 passages in mouse and represent therefore a promising model for studies of tumor-microenvironment interaction. This review summarizes our present knowledge on mouse preclinical cancer models, with a particular attention on patient-derived xenografts of non small cell lung cancer and their relevance for preclinical and biological studies

Ordering of Ge quantum dots on silicon surfaces via bottom-up and top-down approaches

The nanoscale ordering of inorganic semiconductor quantum dots (QDs) is crucial to obtain reliable structures for novel nanotechnological applications such as nanomemories, nanolasers and nanoelectronic devices. We have directly grown Ge QDs by physical vapour deposition (PVD) on Si(111), Si(100) and some of its vicinal surfaces and studied innovative bottom up techniques to order such nanostructures. Specifically, we harnessed naturally occurring instabilities due to reconstruction and intrinsic anisotropic diffusion in Si bare surfaces, such as step bunching and natural steps occurring in silicon vicinal surfaces, to order the QDs both in one dimension and in the plane. We have also shown the use of controlled quantities of surfactants, like Sb, dramatically improves the desired ordering. Moreover, we have assisted these self-assembling processes using top-down approaches like Focused Ion Beam (FIB) milling and STM nanoindentation to control the nucleation sites and the density of the Ge QDs. Real-time study of growth and self-assembly has been accomplished using Scanning Tunneling Microscopy imaging in UHV. An explanation of the occurring processes is given, and a software routine is used to quantify the ordering of the QDs both in pre-patterned and bare surfaces. Applications, mainly in the field of Nanocrystal Nonvolatile Memories, are discussed

HT-SuMD: making molecular dynamics simulations suitable for fragment-based screening. A comparative study with NMR

Fragment-based lead discovery (FBLD) is one of the most efficient methods to develop new drugs. We present here a new computational protocol called High-Throughput Supervised Molecular Dynamics (HT-SuMD), which makes it possible to automatically screen up to thousands of fragments, representing therefore a new valuable resource to prioritise fragments in FBLD campaigns. The protocol was applied to Bcl-XL, an oncological protein target involved in the regulation of apoptosis through protein-protein interactions. Initially, HT-SuMD performances were validated against a robust NMR-based screening, using the same set of 100 fragments. These independent results showed a remarkable agreement between the two methods. Then, a virtual screening on a larger library of additional 300 fragments was carried out and the best hits were validated by NMR. Remarkably, all the in silico selected fragments were confirmed as Bcl-XL binders. This represents, to date, the largest computational fragments screening entirely based on MD

On the relation between body and movement space representation: an experimental investigation on spinal cord injured people

Body Representation (BR) and Movement Space Perception (MSP) are fundamental for human beings in order to move in space and interact with object s and other people. Both BR and space representation change after spinal cord injuries in complete paraplegic individuals (CPP), who suffer from lower limbs paralysis and anesthesia. To date, the interaction between BR and MSP in paraplegic individuals rem ains unexplored. In two consecutive experiments, we tested I ) if the individual\u2019s wheelchair is embodied in BR; and ii) if the embodied wheelchair modifies the MSP. For the first question a speeded detection task was used. Participants had to respond to v isual stimuli flashing on their trunk, legs or wheelchair. In three counterbalanced conditions across participant, they took part to the experiment while: 1) sitting in their wheelchair, 2) in another wheelchair, or 3) with the LEDs on a wooden bar. To in dicate the embodiment, there was no difference in the CPP\u2019s responses for LEDs on the body and personal wheelchair while these were slower in other conditions After this, while sitting in their or another wheelchair, CPPs were asked to judge the slope of a ramp rendered in immersive virtual reality and to estimate the distance of a flag positioned over the ramp. When on their own wheelchair, CPPs perceived the flag closer than in the other wheelchair. These results indicate that the continuous use of a too l induces embodiment and that this i mpact on the perception of MSP

LKB1 Down-Modulation by miR-17 Identifies Patients With NSCLC Having Worse Prognosis Eligible for Energy-Stress–Based Treatments

Abstract Introduction Preclinical models recently unveiled the vulnerability of LKB1/KRAS comutated NSCLC to metabolic stress-based treatments. Because miR-17 is a potential epigenetic regulator of LKB1, we hypothesized that wild-type LKB1 (LKB1WT) NSCLC with high miR-17 expression may be sensitive to an energetic stress condition, and eligible for metabolic frailties-based therapeutic intervention. Methods We took advantage of NSCLC cell lines with different combinations of KRAS mutation and LKB1 deletion and of patient-derived xenografts (PDXs) with high (LKB1WT/miR-17 high) or low (LKB1WT/miR-17 low) miR-17 expression. We evaluated LKB1 pathway impairment and apoptotic response to metformin. We retrospectively evaluated LKB1 and miR-17 expression levels in tissue specimens of patients with NSCLC and PDXs. In addition, a lung cancer series from The Cancer Genome Atlas data set was analyzed for miR-17 expression and potential correlation with clinical features. Results We identified miR-17 as an epigenetic regulator of LKB1 in NSCLC and confirmed targeting of miR-17 to LKB1 3′ untranslated region by luciferase reporter assay. We found that miR-17 overexpression functionally impairs the LKB1/AMPK pathway. Metformin treatment prompted apoptosis on miR-17 overexpression only in LKB1WT cell lines, and in LKB1WT/miR-17 high PDXs. A retrospective analysis in patients with NSCLC revealed an inverse correlation between miR-17 and LKB1 expression and highlighted a prognostic role of miR-17 expression in LKB1WT patients, which was further confirmed by The Cancer Genome Atlas data analysis. Conclusions We identified miR-17 as a mediator of LKB1 expression in NSCLC tumors. This study proposes a miR-17 expression score potentially exploitable to discriminate LKB1WT patients with NSCLC with impaired LKB1 expression and poor outcome, eligible for energy-stress-based treatments