1,267 research outputs found

    On the determination of constitutive parametersin a hyperelastic model for a soft tissue

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    The aim of this paper is to study a model of hyperelastic materials and itsapplications into soft tissue mechanics. In particular, we first determine an unbounded domain of the constitutive parameters of the model making our smoothstrain energy function to be polyconvex and hence satisfying the Legendre–Hadamard condition. Thus, physically reasonable material behaviour are described by our model with these parameters and a plently of tissues can betreated. Furthermore, we localize bounded subsets of constitutive parameters in fixed physical and very general bounds and then introduce a family of descrete stress–strain curves. Whence, various classes of tissues are characterized. Ourgeneral approach is based on a detailed analytical study of the first Piola–Kirchhoff stress tensor through its dependence on the invariants and on the constitutive parameters. The uniqueness of parameters for one tissue is discussed by introducing the notion of manifold of constitutive parameters, whichis locally represented by possibly different physical quantities. The advantage of our study is that we show a possible way to improve of the usual approachesshown in the literature which are mainly based on the minimization of a costfunction as the difference between experimental and model results

    Morphological Characterization of Some Local Varieties of Fig (Ficus carica L.) Cultivated in Southern Italy

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    Figs (Ficus carica L.) are ancient fruits of the Mediterranean basin. In Southern Italy, they are particularly important in the traditional course of local cuisine. In Southern Italy, fig trees are rarely cultivated in specialized orchards but are present in association with other fruit trees (for example, olive, almond, pear, pomegranate, and grapevine). These mixed orchards are particularly important in the traditional agroecosystems of the south of Italy. This study reports preliminary results on the local fig variety’s leaf morphological characterization, aiming to elucidate the presence of synonymousness or homonymy for in situ and ex situ conservation and further exploitation. A field survey was carried out during the summer of 2018 in some areas of the Basilicata district. Thirty local putative varieties were collected, and each of them was identified by GPS coordinates and recorded photographically. Moreover, they were cataloged with the name of the Municipality of origin, year, details of growing location (main crop, mixed orchard, gardens, and single plants), approximate age, and the local name supplied by the donor. All relevant information was included in the accession code. Leaf samples were collected from each accession from medium-length shoots. A digital image of each leaf sample was captured using a digital camera. Leaf morphometric traits were recorded using ImageJ and statistically analyzed using the software PAST 4.11 to discriminate among fig accessions. The multivariate morphometric approach applied correctly classified more than 90% of the leaves and helped to discriminate among accession. Moreover, linear discriminant analysis helped to recognize the presence of different synonymousness and homonymy of different accessions. The results revealed that measured leaf morphometric aided by image analysis could be a simple and inexpensive accessions classification tool

    What drives the valuation of entrepreneurial ventures? A map to navigate the literature and research directions

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    The drivers of the valuations of entrepreneurial ventures are an important issue in entrepreneurial finance, but related research is fragmented. The theoretical perspectives and the drivers highlighted by previous studies differ based on the financial milestones during a venture's lifecycle in which the valuation is performed (e.g., venture capital investments, initial public offerings, acquisitions). The introduction of new digital financing channels (e.g., crowdfunding, initial coin offerings) that allow retail investors to directly invest in entrepreneurial ventures challenge our understanding of the drivers of valuation. This change has also increased the diversity in the sequence of financial milestones that ventures go through, with important implications for valuation. We conduct a systematic literature review and develop a map highlighting how and why the drivers of venture valuations and their underlying theoretical lenses vary across the different milestones that ventures go through. The map allows us to outline new promising avenues for future research.Plain English Summary In this paper, we conduct a systematic literature review on entrepreneurial ventures' valuation drivers and their underlying theoretical lenses, highlighting how and why they vary along firms' life cycle. The valuation of entrepreneurial ventures is a challenging task for practitioners and a relevant issue that attracts the attention of scholars in entrepreneurship, finance, management, and economics. The literature on the topic is highly fragmented. Indeed, the context in which venture valuations are observed (e.g., in private deals or public offerings) differs across different financial milestones. The introduction of new digital financing channels (e.g., crowdfunding, initial coin offerings) and the increased diversity in the sequence of financial milestones that ventures go through further challenge our understanding of valuation drivers. This study is primarily aimed at scholars, offering them a map to create order in what we know about the drivers of entrepreneurial venture valuations and indicating promising avenues for future research

    Level of therapeutic innovation from the registration studies of the new drugs for the prophylaxis of migraine

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    What is known and objective: Migraine is one of the most prevalent and disabling medical illnesses. Preventive drugs are used to reduce the frequency, severity, and duration of attacks. Most patients were no longer on their medication due to contraindications or poor clinical response. Therefore, there is need for novel prophylactic agents for migraine. New preventive treatments are those of the class of calcitonin gene related peptide (CGRP)-targeting therapies. We aimed to assess the real level of therapeutic innovation of these new drugs. Methods: The information on the new drugs was collected from several documents, including the European public assessment reports. The level of therapeutic innovation was assessed with the algorithm published by some of us in 2006. Results: All new approved drugs (eptinezumab, galcanezumab, fremanezumab, erenumab) are indicated for the prophylaxis of migraine in adults who have at least four migraine days for month. All these drugs have been tested only in comparison to placebo. Their level of therapeutic innovation was only modest, that is, the lowest value of our algorithm. Discussion: The new monoclonal antibodies of the class of CGRP targeting therapies have been authorized with efficacy data only against placebo. They do not offer additional clinical benefits compared to available therapies for the prevention of migraine attacks, with the exception of a lower frequency of administration and a more rapid effect. All this assigns to these drugs only a modest role in therapy according to our algorithm for therapeutic innovation with a significantly higher cost than similar therapies

    Safety Profile of Molnupiravir in the Treatment of COVID-19: A Descriptive Study Based on FAERS Data

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    Concerns have been raised about the actual benefit and safety of molnupiravir, a new antiviral treatment for coronavirus disease 2019 (COVID-19). In order to provide additional evidence to support its use, we aimed to evaluate the real safety profile based on post-marketing pharmacovigilance data. Molnupiravir safety data were captured from the FDA Adverse Event Reporting System (FAERS). We performed a descriptive analysis of the baseline demographic characteristics of patients who experienced at least one adverse drug reaction (ADRs) related to molnupiravir, and then evaluated those most frequently reported. As of 31 March 2022, 612 reports of ADRs related to molnupiravir were submitted to the FDA, 301 (49.18%) were related to females and 281 (45.92%) to males. Most reports (524; 85.62%) were submitted by healthcare professionals and 345 (56.37%) concerned serious outcomes. The most common reported ADRs were diarrhoea (57; 4.51%), rash (36; 2.85), nausea (29; 2.30%), and COVID-19 pneumonia (22; 1.74%). The most frequent adverse reactions reported with molnupiravir in the U.S. post-marketing experience are consistent with the safety evaluation of the antiviral medicine. Even if no evident safety concerns emerged, an unexpectedly high rate of serious adverse reactions together with a few cases of potential new adverse reactions occurred

    INTRODUCING CORE-SHELL TECHNOLOGY FOR CONFORMANCE CONTROL

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    Reservoir heterogeneities can severely affect the effectiveness of waterflooding because displacing fluids tend to flow along high-permeability paths and prematurely breakthrough at producing wells. A Proof-of-Concept (PoC) study is presented while discussing the experimental results of a research on "core-shell" technology to improve waterflooding in heterogeneous oil reservoirs. The proposed methodology consists in injecting a water dispersion of nanocapsules after the reservoir has been extensively flushed with water. The nanocapsules are made of a "core" (either polymeric or siliceous materials), protected by a "shell" that can release its content at an appropriate time, which activates through gelation or aggregation thus plugging the high permeability paths. Additional flooding with water provides recovery of bypassed oil. The initial conceptual screening of possible materials was followed by extensive batch and column lab tests. Then, 3D dynamic simulations at reservoir scale were performed to compensate for the temporary lack of pilot tests and/or field applications

    Hardware-Software Co-Design of BIKE with HLS-Generated Accelerators

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    In order to mitigate the security threat of quantum computers, NIST is undertaking a process to standardize post-quantum cryptosystems, aiming to assess their security and speed up their adoption in production scenarios. Several hardware and software implementations have been proposed for each candidate, while only a few target heterogeneous platforms featuring CPUs and FPGAs. This work presents a HW/SW co-design of BIKE for embedded platforms featuring both CPUs and small FPGAs and employs high-level synthesis (HLS) to timely deliver the hardware accelerators. In contrast to state-of-the-art solutions targeting performance-optimized HLS accelerators, the proposed solution targets the small FPGAs implemented in the heterogeneous platforms for embedded systems. Compared to the software- only execution of BIKE, the experimental results collected on the systems-on-chip of the entire Xilinx Zynq-7000 family highlight a performance speedup ranging from 1.37x, on Z-7010, to 2.78x, on Z-7020

    Serratiopeptidase reduces the invasion of osteoblasts by Staphylococcus aureus

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    Finding new strategies to counteract periprosthetic infection and implant failure is a main target in orthopedics. Staphylococcus aureus, the leading etiologic agent of orthopedic implant infections, is able to enter and kill osteoblasts, to stimulate pro-inflammatory chemokine secretion, to recruit osteoclasts, and to cause inflammatory osteolysis. Moreover, by entering eukaryotic cells, staphylococci hide from the host immune defenses and shelter from the extracellular antibiotics. Thus, infection persists, inflammation thrives, and a highly destructive osteomyelitis occurs around the implant. The ability of serratiopeptidase (SPEP), a metalloprotease by Serratia marcescens, to control S. aureus invasion of osteoblastic MG-63 cells and pro-inflammatory chemokine MCP-1 secretion was evaluated. Human osteoblast cells were infected with staphylococcal strains in the presence and in the absence of SPEP. Cell proliferation and cell viability were also evaluated. The release of pro-inflammatory chemokine MCP-1 was evaluated after the exposure of the osteoblast cells to staphylococcal strains. The significance of the differences in the results of each test and the relative control values was determined with Student’s t-test. SPEP impairs their invasiveness into osteoblasts, without affecting the viability and proliferation of bone cells, and tones down their production of MCP-1. We recognize SPEP as a potential tool against S. aureus bone infection and destruction

    Femtosecond Covariance Spectroscopy

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    The success of non-linear optics relies largely on pulse-to-pulse consistency. In contrast, covariance based techniques used in photoionization electron spectroscopy and mass spectrometry have shown that wealth of information can be extracted from noise that is lost when averaging multiple measurements. Here, we apply covariance based detection to nonlinear optical spectroscopy, and show that noise in a femtosecond laser is not necessarily a liability to be mitigated, but can act as a unique and powerful asset. As a proof of principle we apply this approach to the process of stimulated Raman scattering in alpha-quartz. Our results demonstrate how nonlinear processes in the sample can encode correlations between the spectral components of ultrashort pulses with uncorrelated stochastic fluctuations. This in turn provides richer information compared to the standard non-linear optics techniques that are based on averages over many repetitions with well-behaved laser pulses. These proof-of-principle results suggest that covariance based nonlinear spectroscopy will improve the applicability of fs non-linear spectroscopy in wavelength ranges where stable, transform limited pulses are not available such as, for example, x-ray free electron lasers which naturally have spectrally noisy pulses ideally suited for this approach

    Safety profile of paediatric COVID-19 vaccines: An analysis of the US Vaccine Adverse Event Reporting System

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    Aim: To provide further evidence on the safety profile of COVID-19 vaccines in paediatrics by analysing the spontaneous reports of adverse effects related to these vaccines.Methods: Reports related to US paediatric population (from 0 to 17 years) vaccinated with authorised COVID-19 vaccines were extracted from Vaccine Adverse Event Reporting System from December 2020 to 17 November 2022. We conducted a descriptive analysis of Adverse Events Following Immunization (AEFI), calculating reporting rate of serious AEFIs and focusing on myocarditis and Guillain-Barre Syndrome after mRNA COVID-19 vaccines.Results: Overall, 52 720 reports were retrieved: 77% (40541)-Pfizer-BioNTech, 19% (10083)-Moderna, a small proportion for other vaccines 4% (2096). Most of AEFIs were non-serious and listed in corresponding SPCs. Of serious AEFIs, 96% were related to the Pfizer-BioNTech vaccine. Roughly 91% (47874) were related to people from 6 to 17 years, a small percentage of 9% (4773) to the younger group (0-5 years). In both groups, most of the reports were related to mRNA vaccines and the percentage of AEFIs experienced by females were similar to males.Conclusions: Data showed that events most frequently reported were non-serious and listed in the corresponding SPCs, extending the evidence of safety of COVID-19 vaccines authorised in the United States in children
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