94 research outputs found

    Quasi-potentials of the entropy functionals for scalar conservation laws

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    We investigate the quasi-potential problem for the entropy cost functionals of non-entropic solutions to scalar conservation laws with smooth fluxes. We prove that the quasi-potentials coincide with the integral of a suitable Einstein entropy.Comment: 26 pages, 4 figure

    Effective complex conductivity of skeletal muscle in the radio-frequency range

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    This work deals with the dielectric properties of biological tissues comprising tubular cells, such as skeletal muscle. This issue is of significance to many applications for noninvasive diagnosis and treatment, such as electrical impedance tomography, body composition, dialysis, radio-frequency hyperthermia and ablation. The dielectric properties of tissues vary as a function of frequency. Experiments show indeed three dispersions, α, β and γ, mainly attributed to different relaxation processes: ionic diffusion, interfacial polarization and dipolar orientation, respectively. The β dispersion, considered herein, takes place in the radio-frequency range and principally arises from the capacitive charging of cell membranes, known as Maxwell-Wagner effect. Different phenomenological relaxation models are available in the literature, as well as equivalent-circuit models, which however pose the problem of parameter identification. In the present work, a micromechanical approach is used, which enables to derive the effective dielectric properties of the tissue from the properties of the constituent phases and to take into account microstructural details

    How do SUMPs Consider Factors Influencing Walkability and Cyclability? A Review of Literature and Planning Tools

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    Improving active mobility in settlements is one of the EU's core objectives to improve people's quality of life. EU guidelines indicate Sustainable Urban Mobility Plans (SUMPs) as strategic planning tools to achieve sustainable results through the definition of objectives and the provision of actions. Scientific research has extensively explored numerous factors in the built environment and active mobility infrastructures that influence mobility features and demands. However, a gap exists between research and urban plans employed to promote sustainable mobility. This paper examines whether these identified factors from scientific literature have implications for enhancing active mobility actions in Sustainable Urban Mobility Plans. First, a literature review highlights recurring factors in assessing active mobility networks. Then, an overview of actions supporting walkability and cyclability within Sustainable Urban Mobility Plans applied in the Emilia-Romagna Region in Italy is conducted. The two reviews comparison points out the expected implementation gap between research and practice

    Numerical and experimental characterization of a piezoelectric actuator for microfluidic cell sorting

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    Piezoelectric actuators offer great opportunities for precise and low-cost control of fluids at the microscale. Microfluidic systems with integrated piezoelectric actuators find application as droplet generators, micropumps, and microsorters. To accelerate device design and optimization, modeling and simulation approaches represent an attractive tool, but there are challenges arising from the multiphysics nature of the problem. Simple, potentially real-time approaches to experimentally characterize the fluid response to piezoelectric actuation are also highly desirable. In this work, we propose a strategy for the numerical and experimental characterization of a piezoelectric microfluidic cell sorter. Specifically, we present a 3D coupled multiphysics finite-element model of the system and an easy image-based approach for flow monitoring. Sinusoidal and pulse actuation are considered as case studies to test the proposed methodology. The results demonstrate the validity of the approach as well as the suitability of the system for cell sorting applications

    Spontaneous Interfacial Fragmentation of Inkjet Printed Oil Droplets and Their electrical characterization

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    This work presents the fabrication of femtoliter-scale oil droplets by inkjet printing based on a novel mechanism for the spontaneous fragmentation at the interface with an immiscible water phase and the electrical characterization of the resulting immersed “daughter” droplets. [1] In particular, picoliter-scale fluorinated oil droplets impact on surfactant laden water phase at moderately high Weber number (101), and are subjected to spreading and capillary instabilities at the water/air interface which ultimately lead to rupture in smaller sized droplets, according to reported models for macroscale droplets systems - [2] the emerging fragmentation results in “daughter” droplets having volumes of about 10-30 % with respect to the initial droplet volume. Remarkably, the picoliter scale downscaling leads to a novel surfactant-driven fragmentation due to the low Bond number (around 10-4-10-5), meaning that droplet immersion is dependent on surface tension forces and not on gravitational forces. In fact, the non-ionic Polyoxyethylene (20) sorbitan monolaurate was observed to permit the droplet immersion in the water phase only if spiked in the water phase at concentrations equal or higher than its critical micellar concentration (i.e. around 0.003% v/v). The resulting oil “daughter” droplets are characterized by a chip with integrated microelectrodes, permitting to extract number, velocities and diameter distribution (peaked at about 3 m) employing electrical impedance measurements. In accordance with reported models, the electrical characterizations show that the droplets have volumes in the femtoliter scale and are subjected to inertial focusing. [3] This work can be considered an important advancement for understanding the effects of downscaling on fragmentation phenomena at immiscible interfaces, leading to a knowledge platform for a tailored oil droplets fabrication applicable for drug encapsulation, pharmaceutic preparations, and thin-film wrapping around droplets. [4] Bibliography 1. D. Spencer, F. Caselli, P. Bisegna and H. Morgan., Lab Chip, 2016, 16, 2467. 2. H. Lhuissier, C. Sun, A. Prosperetti, and D. Lohse, Phys. Rev. Lett., 2013, 110, 3. G. Arrabito, V. Errico, A. De Ninno, F. Cavaleri, V. Ferrara, B. Pignataro, and F.Caselli, Langmuir, 2019, 35, 4936. 4. D. Kumar, J. D. Paulsen, T. P. Russell, N. Menon, Science, 2018, 359, 775

    Homo sapiens natriuretic peptide precursor type C (NPPC) mRNA,partial cds and 3\u27 UTR.

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    LOCUS HQ419060 318 bp mRNA linear PRI 24-NOV-2010 DEFINITION Homo sapiens natriuretic peptide precursor type C (NPPC) mRNA, partial cds and 3\u27 UTR. ACCESSION HQ419060 VERSION HQ419060.1 GI:312261407 KEYWORDS . SOURCE Homo sapiens (human) ORGANISM Homo sapiens Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia; Eutheria; Euarchontoglires; Primates; Haplorrhini; Catarrhini; Hominidae; Homo. REFERENCE 1 (bases 1 to 318) AUTHORS Landi,S., Melaiu,O., Cabiati,M., Landi,D., Caselli,C., Prescimone,T., Giannessi,D., Gemignani,F. and Del Ry,S. TITLE Direct Submission JOURNAL Submitted (20-OCT-2010) Laboratory of Cardiovascular Biochemistry, Institute of Clinical Physiology, Via Moruzzi 1, Pisa, PI 56100, Italy FEATURES Location/Qualifiers source 1..318 /organism="Homo sapiens" /mol_type="mRNA" /db_xref="taxon:9606" /cell_line="SKNBE" /PCR_primers="fwd_seq: gtcagaagaagggcgacaag, rev_seq: gcgtttaaacgcgcacgcgt" gene <1..318 /gene="NPPC" CDS <1..188 /gene="NPPC" /codon_start=3 /product="natriuretic peptide precursor type C" /protein_id="ADQ54381.1" /db_xref="GI:312261408" /translation="GDRSRLLRDLRVDTKSRAAWARLLQEHPNARKYKGANKKGLSKG CFGLKLDRIGSMSGLGC" 3\u27UTR 189..318 /gene="NPPC" ORIGIN 1 agggcgaccg gtcgcgactg ctccgggacc tgcgcgtgga caccaagtcg cgggcagcgt 61 gggctcgcct tctgcaagag caccccaacg cgcgcaaata caaaggagcc aacaagaagg 121 gcttgtccaa gggctgcttc ggcctcaagc tggaccgaat cggctccatg agcggcctgg 181 gatgttagtg cggcgccccc tggcggcggg agaagaatga ttctgacact tggggaccag 241 ccttcagtag ctacccttgg aatgcctttg ctctcttctc tcctgtctaa acaacaaaga 301 gacggagtct gaggcct

    Rapid Assessment of Susceptibility of Bacteria and Erythrocytes to Antimicrobial Peptides by Single-Cell Impedance Cytometry

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    Antimicrobial peptides (AMPs) represent a promising classof compoundsto fight antibiotic-resistant infections. In most cases, they killbacteria by making their membrane permeable and therefore exhibitlow propensity to induce bacterial resistance. In addition, they areoften selective, killing bacteria at concentrations lower than thoseat which they are toxic to the host. However, clinical applicationsof AMPs are hindered by a limited understanding of their interactionswith bacteria and human cells. Standard susceptibility testing methodsare based on the analysis of the growth of a bacterial populationand therefore require several hours. Moreover, different assays arerequired to assess the toxicity to host cells. In this work, we proposethe use of microfluidic impedance cytometry to explore the actionof AMPs on both bacteria and host cells in a rapid manner and withsingle-cell resolution. Impedance measurements are particularly well-suitedto detect the effects of AMPs on bacteria, due to the fact that themechanism of action involves perturbation of the permeability of cellmembranes. We show that the electrical signatures of Bacillus megaterium cells and human red blood cells(RBCs) reflect the action of a representative antimicrobial peptide,DNS-PMAP23. In particular, the impedance phase at high frequency (e.g.,11 or 20 MHz) is a reliable label-free metric for monitoring DNS-PMAP23bactericidal activity and toxicity to RBCs. The impedance-based characterizationis validated by comparison with standard antibacterial activity assaysand absorbance-based hemolytic activity assays. Furthermore, we demonstratethe applicability of the technique to a mixed sample of B. megaterium cells and RBCs, which paves the wayto study AMP selectivity for bacterial versus eukaryotic cells inthe presence of both cell types

    Myocardial interleukin-6 in the setting of left ventricular mechanical assistance: relation with outcome and C-reactive protein

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    Background: In left ventricular assist device (LVAD) recipients, plasma levels of interleukin (IL)-6 are associated with Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) profiles, reflecting postoperative risk. However, it is not clear how the cardiac. Conclusions: Cardiac IL-6 levels do not contribute to improve risk profile of LVAD recipients in relation to clinical inpatient post-implantation. Instead, plasma IL-6 and serum CRP concentrations are more effective in predicting the severity of the clinical course in the early phase of LVAD therapy. level of IL-6, detectable on the tissue samples at the time of implantation, can contribute to predict the post-operative outcome
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