167 research outputs found
Aprotic sulfur-metal batteries: lithium and beyond
Metal-sulfur batteries constitute an extraordinary research playground that ranges from fundamental science to applied technologies. However, besides the widely explored Li-S system, a remarkable lack of understanding hinders advancements and performance in all other metal-sulfur systems. In fact, similarities and differences make all generalizations highly inconsistent, thus unavoidably suggesting the need for extensive research explorations for each formulation. Here we review critically the most remarkable open challenges that still hinder the full development of metal-S battery formulations, starting from the lithium benchmark and addressing Na, K, Mg, and Ca metal systems. Our aim is to draw an updated picture of the recent efforts in the field and to shed light on the most promising innovation paths that can pave the way to breakthroughs in the fundamental comprehension of these systems or in battery performance
Chromium-Doped Nickel Cobaltite Nanoneedles as a Cathodic Material for Li-O2Cells: An X-ray Photoemission and Photoabsorption Spectroscopy Investigation
Li-O2 redox chemistry in aprotic electrolytes is promising to boost the performance of secondary batteries, displaying a theoretical energy density more than an order of magnitude higher than the present state-of-the-art Li-ion technology. However, the electrochemical Li2O2 formation and dissolution occur in parallel with the so-called ORR and OER (i.e., oxygen reduction reaction and oxygen evolution reaction, respectively), thus requiring suitable electrocatalysts to promote the redox kinetics both in discharge and charge. Here, we discuss the electronic structure and the surface chemistry of a nanoneedle-structured nickel cobaltite doped with chromium as a heterogeneous electrocatalyst for aprotic Li-O2 cells. A detailed experimental study of the evolution of occupied and unoccupied electronic states of the material from the pristine to a post-mortem condition after operation as a cathode in a Li-O2 cell is undertaken via ex situ X-ray photoemission (X-ray photoelectron spectroscopy, XPS) and photoabsorption (near-edge X-ray absorption fine structure NEXAFS) spectroscopies. This analysis proved the mixed valence state of the transition metals, their coordination environment within the cobaltite matrix, and their evolution after operation in the cell. In particular, spectroscopic fingerprints of deposition/dissolution phenomena due to solvent degradation were found in the C 1s XP spectra after operation in the Li-O2 cell, together with an involvement of Ni2+/3+ centers in the electrocatalytic processes of oxygen reduction and evolution, enhanced in the presence of a Cr(III) dopant
Clinical experience with power-injectable PICCs in intensive care patients
Introduction: In the ICU, peripherally inserted central catheters (PICCs) may be an alternative option to standard central venous catheters, particularly in patients with coagulation disorders or at high risk for infection. Some limits of PICCs (such as low flow rates) may be overcome with the use of power-injectable catheters.Methods: We retrospectively reviewed all of the power-injectable PICCs inserted in adult and pediatric patients in the ICU during a 12-month period, focusing on the rate of complications at insertion and during maintenance.Results: We collected 89 power-injectable PICCs (in adults and in children), both multiple and single lumen. All insertions were successful. There were no major complications at insertion and no episodes of catheter-related bloodstream infection. Non-infective complications during management were not clinically significant. There was one episode of symptomatic thrombosis during the stay in the ICU and one episode after transfer of a patient to a non-intensive ward.Conclusion: Power-injectable PICCs have many advantages in the ICU: they can be used as multipurpose central lines for any type of infusion including high-flow infusion, for hemodynamic monitoring, and for high-pressure injection of contrast media during radiological procedures. Their insertion is successful in 100% of cases and is not associated with significant risks, even in patients with coagulation disorders. Their maintenance is associated with an extremely low rate of infective and non-infective complications. © 2012 Pittiruti et al.; licensee BioMed Central Ltd
Immune activation, immune senescence and levels of Epstein Barr Virus in kidney transplant patients: Impact of mTOR inhibitors
Post-transplant lymphoproliferative disorders (PTLD) represent a severe complication in transplanted patients and Epstein-Barr Virus (EBV) is the main driver. Besides immunodepression, immune activation/chronic inflammation play an important role in both virus reactivation and expansion of EBV-positive B cells. The aim of this study was to assess the impact of immunosuppressive strategies on factors involved in the PTLD's pathogenesis. 124 kidney transplanted patients were enrolled in this study: 71 were treated with mycophenolic acid (MPA) and 53 treated with mTOR inhibitor (mTORi), both in combination with different doses of calcineurin inhibitor. At the time of the transplant (T0), profile of inflammation/immune activation and immune senescence didn't differ between the two groups, but after one year of treatment (T1) markers were significantly higher in MPA-treated patients; their immunosenescence process was supported by the greater erosion of telomeres despite their younger age. Percentages of activated B cells and levels of EBV-DNA significantly increased in MPA-treated patients, and at T1 were significantly higher in MPA- than in mTORi-treated patients. Overall, these findings indicate that mTOR inhibitors constrain the inflammation/immune activation and senescence status, thus reducing the expansion of EBV-infected B cells and the risk of virus-associated PTLD in kidney transplant recipients. \ua9 2019 The Author
Tumor-Infiltrating Lymphocyte Recognition in Primary Melanoma by Deep Learning Convolutional Neural Network
The presence of tumor-infiltrating lymphocytes (TILs) is associated with a favorable prognosis of pri-mary melanoma (PM). Recently, artificial intelligence (AI)-based approach in digital pathology was proposed for the standardized assessment of TILs on hematoxylin and eosin-stained whole slide images (WSIs). Herein, the study applied a new convolution neural network (CNN) analysis of PM WSIs to automatically assess the infiltration of TILs and extract a TIL score. A CNN was trained and validated in a retrospective cohort of 307 PMs including a training set (237 WSIs, 57,758 patches) and an inde-pendent testing set (70 WSIs, 29,533 patches). An AI-based TIL density index (AI-TIL) was identified after the classification of tumor patches by the presence or absence of TILs. The proposed CNN showed high performance in recognizing TILs in PM WSIs, showing 100% specificity and sensitivity on the testing set. The AI-based TIL index correlated with conventional TIL evaluation and clinical outcome. The AI-TIL index was an independent prognostic marker associated directly with a favorable prognosis. A fully automated and standardized AI-TIL appeared to be superior to conventional methods at differentiating the PM clinical outcome. Further studies are required to develop an easy-to-use tool to assist pathologists to assess TILs in the clinical evaluation of solid tumors. (Am J Pathol 2023, 193: 2099-2110; https://doi.org/10.1016/j.ajpath.2023.08.013
Study of the effect of contact force model on the dynamic response of mechanical systems with dry clearance joints : computational and experimental approaches
The main objective of this work is to present a computational and experimental study on the contact forces developed in revolute clearance joints. For this purpose, a well-known slider-crank mechanism with a revolute clearance joint between the connecting rod and slider is utilized. The intra-joint contact forces that generated at this clearance joints are computed by considered several different elastic and dissipative approaches, namely those based on the Hertz contact theory and the ESDU tribology-based for cylindrical contacts, along with a hysteresis-type dissipative damping. The normal contact force is augmented with the dry Coulomb’s friction force. In addition, an experimental apparatus is use to obtained some experimental data in order to verify and validate the computational models. From the outcomes reported in this paper, it is concluded that the selection of the appropriate contact force model with proper dissipative damping plays a significant role in the dynamic response of mechanical systems involving contact events at low or moderate impact velocities.Fundação para a Ciência e a Tecnologia (FCT
Coupling dynamics of a geared multibody system supported by Elastohydrodynamic lubricated cylindrical joints
A comprehensive computational methodology to study the coupling dynamics of a geared multibody system supported by ElastoHydroDynamic (EHD) lubricated cylindrical joints is proposed throughout this work. The geared multibody system is described by using the Absolute-Coordinate-Based (ACB) method that combines the Natural Coordinate Formulation (NCF) describing rigid bodies and the Absolute Nodal Coordinate Formulation (ANCF) characterizing the flexible bodies. Based on the finite-short bearing approach, the EHD lubrication condition for the cylindrical joints supporting the geared system is considered here. The lubrication forces developed at the cylindrical joints are obtained by solving the Reynolds’ equation via the finite difference method. For the evaluation of the normal contact forces of gear pair along the Line Of Action (LOA), the time-varying mesh stiffness, mesh damping and Static Transmission Error (STE) are utilized. The time-varying mesh stiffness is calculated by using the Chaari’s methodology. The forces of sliding friction along the Off-Line-Of-Action (OLOA) are computed by using the Coulomb friction models with a time-varying coefficient of friction under the EHD lubrication condition of gear teeth. Finally, two numerical examples of application are presented to demonstrate and validate the proposed methodology.National Natural Science Foundations of China under Grant
11290151, 11221202 and 11002022, Beijing Higher
Education Young Elite Teacher Project under Grant YETP1201
I progetti gestiti dai Coordinatori: analisi del loro profilo e successo
Obiettivo. Descrivere la storia dei progetti affidati/
gestiti dai Coordinatori infermieristici ospedalieri. Metodi.
\uc8 stato incluso un campione di 56 Coordinatori in ruolo
da almeno un anno nei reparti di 13 Ospedali del nord
Italia, contattati con criterio di convenienza. Tramite un\u2019intervista
strutturata sono stati raccolti dati sui progetti gestiti
nel 2009, tipologia, origine (bottom up; top down), il
numero di operatori coinvolti e stato del progetto al momento
dell\u2019intervista (concluso, incompleto, abbandonato).
Risultati. Nel 2009 i Coordinatori hanno gestito 114 progetti,
in media 1.8/ciascuno (\ub11.2): 94 (82.5%) erano progetti
di miglioramento, 17 (14.9%) di accreditamento, e 3
(2.6%) di ricerca. I progetti avevano coinvolto complessivamente
2.732 persone (73.7% dei team) con un impegno medio
di 84 ore ciascuno; 55 (48.2%) progetti erano ancora in
corso, 52 (45.6%) conclusi, 5 (4.4%) incompleti (ovvero mancavano
di valutazione) mentre 2 (1.8%) erano stati abbandonati.
Conclusioni. Gli infermieri sono coinvolti in numerosi
progetti nelle aziende sanitarie. La fase pi\uf9 trascurata
\ue8 il monitoraggio dei risultati e il loro consolidamento: i
progetti assorbono molte risorse e per questo \ue8 fondamentale
che siano correttamente gestiti e partano da reali problemi
ed esigenze dei pazienti
- …