The hemostatic system. 1st Part

The hemostatic system is a complex ancestral pathway physiologically dedicated to protect the individual from bleeding. It starts immediately after an endothelial injury. Platelets and blood coagulation act synergically to provide a strength clot able to stop bleeding. In healthy subjects, the hemostatic system is able to work to avoid an excess of fibrin formation and deposition within the blood vessels on the one hand but is ready to stop bleeding on the other. To reach this crucial objective, a fine regulation of its activity is required. In other words, all actions of the hemostatic system are under control to assure a perfect balance to maintain people distant from both Scylla (bleeding) and Charybdis (thrombosis). Fibrinolysis is a complementary defensive system essential to regulate fibrin deposition via its dissolution. It is, in turn, well controlled to avoid bleeding and thrombosis by a fine control of its inducers and inhibitors. The aim of this review is to provide a picture of global haemostasis for helping in understanding this complex topic

A RISC-V-based FPGA Overlay to Simplify Embedded Accelerator Deployment

Modern cyber-physical systems (CPS) are increasingly adopting heterogeneous systems-on-chip (HeSoCs) as a computing platform to satisfy the demands of their sophisticated workloads. FPGA-based HeSoCs can reach high performance and energy efficiency at the cost of increased design complexity. High-Level Synthesis (HLS) can ease IP design, but automated tools still lack the maturity to efficiently and easily tackle system-level integration of the many hardware and software blocks included in a modern CPS. We present an innovative hardware overlay offering plug-and-play integration of HLS-compiled or handcrafted acceleration IPs thanks to a customizable wrapper attached to the overlay interconnect and providing shared-memory communication to the overlay cores. The latter are based on the open RISC-V ISA and offer simplified software management of the acceleration IP. Deploying the proposed overlay on a Xilinx ZU9EG shows ≈ 20% LUT usage and ≈ 4× speedup compared to program execution on the ARM host core

Vibro-Acoustic Modulation with broadband pump excitation for efficient impact damage detection in composite materials

In the past few decades, the need for efficient and reliable Structural Health Monitoring strategies has led to the development of several approaches for damage detection and characterization purposes. Among them, the Nonlinear Vibro-Acoustic Modulation (VAM) exploits the modulation arising from the interaction of two concurrently applied driving waves, namely the probe and the pump excitations, in the presence of nonlinear scatters such as cracks and defects. Therefore, the VAM provides information on the emergence of internal damage by extracting the nonlinear modulated components of the response of a damaged system. Originally proposed for granular media, the method has shown to be effective in detecting the presence of defects also in metals and composite materials. Nonetheless, its efficacy is highly affected by the excitation frequencies, which are usually chosen among the system resonances. The need for a preliminary modal analysis and, at once, the risk of selecting pump-probe frequency combinations with low sensitivity to damage may make the procedure time-consuming and not fully reliable, preventing the VAM technique from being widely accepted as a robust monitoring tool. To overcome these limitations, a broadband excitation may be used. This study assesses the effectiveness of the VAM technique when a combination of a frequency-swept pump excitation and a mono-harmonic probe wave is applied to drive the sample. Experimental tests were conducted on a composite laminated beam mounted on an electrodynamic shaker and tested in both pristine and damaged conditions. Low-profile surface-bonded piezoceramic transducers were used for both probe excitation and sensing. Barely visible impact damage (BVID) was introduced in the composite beam to examine the potential of the approach for the detection of very small, localized damage. The results show that the use of VAM with a broadband low-frequency excitation may be an effective option for identifying nonlinearities associated with typical damage occurring in composite structures

Reliability and reproducibility of the new AO/OTA 2018 classification system for proximal humeral fractures: a comparison of three different classification systems

Background: The classification systems for proximal humeral fractures routinely used in clinical practice include the Neer and Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association (AO/OTA) 2007 systems. Currently used systems have low inter- and intraobserver reliability. In 2018, AO/OTA introduced a new classification system with the aim of simplifying the coding process, in which the Neer four-part classification was integrated into the fracture description. The aim of the present work is to assess the inter- and intraobserver agreement of the new AO/OTA 2018 compared with the Neer and AO/OTA 2007 classifications. Materials and methods: A total of 116 radiographs of consecutive patients with proximal humeral fracture were selected and classified by three observers with different levels of experience. All three observers independently reviewed and classified the images according to the Neer, AO/OTA 2007, and new AO/OTA 2018 systems. To determine the intraobserver agreement, the observers reviewed the same set of radiographs after an interval of 8 weeks. The inter- and intraobserver agreement were determined through Cohen’s kappa coefficient analysis. Results: The new AO/OTA 2018 classification showed substantial mean inter- (k=0.67) and intraobserver (k=0.75) agreement. These results are similar to the reliability observed for the Neer classification (interobserver, k=0.67; intraobserver, k=0.85) but better than those found for the AO/OTA 2007 system, which showed only moderate inter- (k=0.57) and intraobserver (k=0.58) agreement. The two more experienced observers showed better overall agreement, but no statistically significant difference was found. No differences were found between surgical experience and agreement regarding specific fracture types or groups. Conclusions: The results showed that the Neer system still represents the more reliable and reproducible classification. However, the new AO/OTA 2018 classification improved the agreement among observers compared with the AO/OTA 2007 system, while still maintaining substantial descriptive power and simplifying the coding process. The universal modifiers and qualifications, despite their possible complexity, allowed a more comprehensive fracture definition without negatively affecting the reliability or reproducibility of the classification system. Level of evidence: Level III, diagnostic studie

A new photophysics for 2D and 3D lead halide perovskites: Polaron plasma in equilibrium with bright excitons

Rapid advances in perovskite photovoltaics have produced efficient solar cells, with stability and duration improving thanks to variations in materials composition, including the use of layered 2D perovskites. A major reason for the success of perovskite photovoltaics is the presence of free carriers as majority optical excitations in 3D materials at room temperature. On the other hand, the current understanding is that in 2D perovskites or at cryogenic temperatures insulating bound excitons form, which need to be split in solar cells and are not beneficial to photoconversion. Here we apply a tandem spectroscopy technique that combines ultrafast photoluminescence and differential transmission to demonstrate a plasma of unbound charge carriers in chemical equilibrium with a minority phase of light-emitting excitons, even in 2D perovskites and at cryogenic temperatures. We validate the technique with 3D perovskites and investigate 2D compounds basded on both Pb and Sn as metal cation. The underlying photophysics is interpreted as formation of large polarons, charge carriers coupled to lattice deformations, in place of excitons. A conductive polaron plasma foresees novel mechanisms for LEDs and lasers, as well as a prominent role for 2D perovskites in photovoltaics

Orthogeriatric Assessment of the Elderly Patient with Fragility Hip Fracture: Preliminary Results of a Prospective Study

Nowadays, more studies deal with “OrthoGeriatrics”, for the co-management of elderly patients suffering fractures, from the admission to the discharge and beyond. For the first time at Cagliari University Hospital, we introduced an orthogeriatric service, in which trained geriatricians stay in orthopedic unit alongside trained orthopedics. The primary aim of the study was to analyze the rate of death and rehospitalization in elderly femur-fractured people of 65 or more years of age, identifying possible predictive factors. The secondary aim of the study was to analyze the recovery of daily living autonomies during the months following surgery. To reach the aim, we designed a prospective study, which is currently ongoing. We evaluated femur-fractured patients aged 65 years or more with a comprehensive geriatric assessment before surgery. The most common fractures were lateral hip ones, treated with osteosynthesis. Cognitive–affective, functional, and nutritional status, mood, and comorbidities were less impaired than in the outpatient service of the same hospital devoted to frail elderly. Pain control was excellent. A significantly low delirium incidence was found. More than a third of the sample were recognized as frail (according to the Survey of Health, Ageing and Retirement in Europe—Frailty Instrument (SHARE-FI)), and over a third of the sample were identified as a moderate-high risk of hospitalization and death (according to Multidimensional Prognostic Index (MPI)). Overall mortality rate was 13.87%, and rehospitalization rate was 11.84%. Frail people were more likely to die than non-frail (HR: 5.64), and pre-frail ones (HR: 3.97); similarly, high-risk patients were more likely to die than low-risk (HR: 8.04), and moderate-risk ones (HR: 5.46). Conversely, neither SHARE-FI nor MPI predicted rehospitalization. Creatinine (OR: 2.66, p = 0.003) and folate (OR: 0.75, p = 0.03) levels were independently associated with death and rehospitalization, respectively. Finally, the patients did recover the lost autonomies later, 6 months after surgery. Our study demonstrated that SHARE-FI and MPI are reliable tools to predict mortality in an orthogeriatric setting, and that creatinine and folate levels should also be measured given their independent association with negative outcomes

Heparins and 2019-nCoV infection: a narrative review

Abstract. – OBJECTIVE: Patients with 2019-nCoV infection have a high risk to develop venous thrombotic events. Several guidelines recommend the use of either unfractionated heparin or low molecular weight heparins in preventing thrombotic events in these patients. However, results from clinical studies, so far published, reached controversial conclusions on heparin efficacy in this kind of patients since the incidence of venous thromboembolism remains high despite prophylaxis. This narrative review aims to provide an overview of the antiviral and anti-inflammatory properties of heparins and their efficacy and safety in SARSCoV-2 medical ward-patients. Moreover, anatomical findings and ongoing trials are also reported. Finally, this narrative review tries to explain why heparins fail to prevent venous thrombosis. MATERIALS AND METHODS: We searched for the most relevant published studies on heparins and 2019-nCoV infected patients using the MEDLINE electronic database in the period between January and December 2020. Articles were preliminarily defined as eligible if they: a) were in English language, b) enrolled 250 or more medical ward-patients and 100 or more ICU-patients, c) reported results on patients treated with heparins in a percentage of at least 70% and d) performed an objectively confirmed diagnosis of VTE. RESULTS: Data from medium to large scientific studies show that the incidence of venous thrombotic events in medical ward-patients with SARS-CoV-2 vary between 0% and 8.3%, while this rate is higher, from 6.2% to 49%, in Intensive Care Unit-patients. However, heparins reduce the mortality rate in these patients of about 50%. Histological findings show that thrombosis could affect capillaries, main and small-midsized vessels, and it is associated with diffuse alveolar damage. CONCLUSIONS: Heparins have anti-inflammatory and anti-viral properties, which may be of help in reducing mortality in SARS-CoV-2 patients. Failure of heparins at prophylactic dosages in preventing VTE, especially in ICU-patients, could be due to the severity of the disease. Data on the use of heparins in an early phase of the 2019-nCoV infection are still lacking

Strong Anharmonicity at the Origin of Anomalous Thermal Conductivity in Double Perovskite Cs2 NaYbCl6

Anomalous thermal transport of Cs2 NaYbCl6 double-halide perovskite above room temperature is reported and rationalized. Calculations of phonon dispersion relations and scattering rates up to the fourth order in lattice anharmonicity have been conducted to determine their effective dependence on temperature. These findings show that specific phonon group velocities and lifetimes increase if the temperature is raised above 500 K. This, in combination with anharmonicity, provides the microscopic mechanism responsible for the increase in lattice thermal conductivity at high temperatures, contrary to the predictions of phonon transport theories based on solely cubic anharmonicity. The model accurately and quantitatively reproduces the experimental thermal conductivity data as a function of temperature

Halide double-perovskites: High efficient light emission and beyond

Lead-free halide double perovskites are stable and versatile materials for a wide range of applications, particularly for lighting, thanks to their very efficient emission of warm white light. Element substitution in halide double perovskite is recognized as a powerful method for tuning the emission wavelength and improve the efficiency. This review provides an overview on composition and recent progress in halide double perovskite with main focus on the synthesis and emission properties of chloride-based compounds