435 research outputs found
Controlling the Cassie-to-Wenzel Transition: an Easy Route towards the Realization of Tridimensional Arrays of Biological Objects
In this paper we provide evidence that the Cassie-to-Wenzel transition, despite its detrimental effects on the wetting properties of superhydrophobic surfaces, can be exploited as an effective micro-fabrication strategy to obtain highly ordered arrays of biological objects. To this purpose we fabricated a patterned surface wetted in the Cassie state, where we deposited a droplet containing genomic DNA. We observed that, when the droplet wets the surface in the Cassie state, an array of DNA filaments pinned on the top edges between pillars is formed. Conversely, when the Cassie-to-Wenzel transition occurs, DNA can be pinned at different height between pillars. These results open the way to the realization of tridimensional arrays of biological objects
Recurrence quantification analysis of heart rate variability to detect both ventilatory thresholds
Aims of this study were: To verify if Recurrence Quantification Analysis (RQA) of Heart Rate Variability (HRV) time series could determine both ventilatory thresholds in individuals with different fitness levels, and to assess the validity of RQA method compared to gasexchange method (GE). The two thresholds were estimated in thirty young individuals during incremental exercise on cycle-ergometer: Heart rate (HR), Oxygen consumption (VO2) and Workload were measured by the two methods (RQA and GE). Repeated measures ANOVA was used to assess main effects of methods and methods-by-groups interaction effects for HR, VO2 and Workload at aerobic (AerT) and anaerobic (AnT) thresholds. Validity of RQA at both thresholds was assessed for HR, VO2 and Workload by Ordinary Least Products (OLP) regression, Typical Percentage Error (TE), Intraclass Correlation Coefficients (ICC) and the Bland Altman plots. No methods-by-groups interaction effects were detected for HR, VO2 and Workload at AerT and AnT. The OLP analysis showed that at both thresholds RQA and GE methods had very strong correlations (r >0.8) in all variables (HR, VO2 and Workload). Slope and intercept values always included the 1 and the 0, respectively. At AerT the TE ranged from 4.02% (5.48 bpm) to 10.47% (8.53 Watts) (HR and Workload, respectively) and in all variables ICC values were excellent (≥0.85). At AnT the TE ranged from 2.53% (3.98 bpm) to 6.64% (7.81 Watts) (HR and Workload, respectively) and in all variables ICC values were excellent (≥0.90). Therefore, RQA of HRV time series is a new valid approach to determine both ventilatory thresholds in individuals with different physical fitness levels, it can be used when gas analysis is not possible or not convenient
VP6-SUMO Self-Assembly as Nanocarriers for Gastrointestinal Delivery
High proteolytic degradation and poor absorption through epithelial barriers are major challenges to successful oral delivery of therapeutics. Nanoparticle platforms can enhance drug stability and extend the residence time in gastrointestinal (GI) tract. However, drug delivery systems are often inactivated in acidic environment of stomach or suffer poor absorption from intestinal cells due to the mucus layer. To overcome these issues we developed a drug delivery system constituted by a protein construct made by a Rotavirus capsid protein (VP6) and the small ubiquitin-like modifier SUMO. This chimeric construct allows specificity towards intestinal cells, the Rotavirus natural target, combined by an enhanced stability given by the eukaryotic protein transporter SUMO. Furthermore SUMO can act as a molecular switch that facilitates import/export of its ligand to the nucleus, the hypersensitive subcellular site target of many cell killing therapies. In this paper we show that SUMO-VP6 constructs self-assembly into stable nanocarriers. SUMO-VP6 nanocarriers display ideal features for drug delivery: a small size and high monodispersity, a high stability in different pH conditions and a high uptake in the nuclear and cytoplasmic compartment of intestinal cells. These features make SUMO-VP6 nanocarriers a promising novel system for oral delivery of poorly soluble drugs
Ex vivo effect of vascular wall stromal cells secretome on enteric ganglia
BACKGROUND Mesenchymal stromal cell (MSC)-based therapy is currently under study to treat inflammatory bowel diseases. MSC bioactive products could represent a valid alternative to overcome issues associated with systemic whole-cell therapies. However, MSC anti-inflammatory mechanisms differ between rodents and humans, impairing the reliability of preclinical models. AIM To evaluate the effect of conditioned medium (CM) derived from porcine vascular wall MSCs (pVW-MSCs) on survival and differentiation of porcine and Guinea pig enteric ganglia exposed to lipopolysaccharide (LPS). METHODS Primary cultures of enteric ganglia were obtained by mechanic and enzymatic digestion of ileum resections from Guinea pigs (Cavia porcellus) (GPEG) and pigs (Suus scrofa) (PEG). pVW-MSCs were derived by enzymatic digestion from vascular wall resections of porcine aorta and tested by immunoflowcytometry for MSC immune profile. Enteric ganglia were treated with increasing concentrations of LPS, CM derived by pVW-MSCs or a combination of CM and LPS 1 \u3bcg/mL. Cell count and morphometric analysis of HuD positive neurons and glial fibrillary acidic protein positive glial cells were performed by immunofluorecent staining of cultured ganglia. RESULTS PEG showed a higher number of neurons compared to GPEG. Overall, CM exerted a protective role on LPS-treated enteric ganglia. CM in combination with LPS increased the number of glial cells per ganglion in both cultures evoking glial cells differentiation in porcine cultures. CONCLUSION These findings suggest an immunomodulating activity of pVW-MSCs mediators on the enteric nervous system in inflammatory conditions
Terahertz detection by epitaxial-graphene field-effect-transistors on silicon carbide
We report on room temperature detection of terahertz radiation by means of antenna-coupled field effect transistors (FETs) fabricated using epitaxial graphene grown on silicon carbide. The achieved photoresponsivity (similar to 0.25 V/W) and noise equivalent power (similar to 80 nW/root Hz) result from the combined effect of two independent detection mechanisms: over-damped plasma wave rectification and thermoelectric effects, the latter ascribed to the presence of carrier density junctions along the FET channel. The calculated plasmonic and thermoelectric response reproduces qualitatively well the measured photovoltages; the experimentally observed sign-switch demonstrates the stronger contribution of plasmonic detection compared to the thermoelectric one. These results unveil the potential of plasmonic detectors exploiting epitaxial graphene on silicon carbide for fast large area imaging of macroscopic samples
High performance bilayer-graphene Terahertz detectors
We report bilayer-graphene field effect transistors operating as THz
broadband photodetectors based on plasma-waves excitation. By employing
wide-gate geometries or buried gate configurations, we achieve a responsivity
and a noise equivalent power in the 0.29-0.38 THz range, in photovoltage and photocurrent mode.
The potential of this technology for scalability to higher frequencies and the
development of flexible devices makes our approach competitive for a future
generation of THz detection systems
Graphene Plasmonic Fractal Metamaterials for Broadband Photodetectors
Metamaterials have recently established a new paradigm for enhanced light absorption in state-of-the-art photodetectors. Here, we demonstrate broadband, highly efficient, polarization-insensitive, and gate-tunable photodetection at room temperature in a novel metadevice based on gold/graphene Sierpinski carpet plasmonic fractals. We observed an unprecedented internal quantum efficiency up to 100% from the near-infrared to the visible range with an upper bound of optical detectivity of 1011 Jones and a gain up to 106, which is a fingerprint of multiple hot carriers photogenerated in graphene. Also, we show a 100-fold enhanced photodetection due to highly focused (up to a record factor of |E/E0| ≈ 20 for graphene) electromagnetic fields induced by electrically tunable multimodal plasmons, spatially localized in self-similar fashion on the metasurface. Our findings give direct insight into the physical processes governing graphene plasmonic fractal metamaterials. The proposed structure represents a promising route for the realization of a broadband, compact, and active platform for future optoelectronic devices including multiband bio/chemical and light sensors
Mepolizumab Improves Outcomes of Chronic Rhinosinusitis with Nasal Polyps in Severe Asthmatic Patients: A Multicentric Real-Life Study
Objective: The upcoming introduction of mepolizumab represents a promising treatment for chronic rhinosinusitis with nasal polyps (CRSwNP). The present study aimed to evaluate the effectiveness of mepolizumab on sinonasal outcomes of comorbid CRSwNP and severe asthma in a real-life setting. The primary endpoint was to evaluate changes in the SinoNasal Outcome Test (SNOT)-22 score, Nasal Polyp (NP) score, and blood eosinophil count during a 12-month treatment with mepolizumab. Secondary endpoints were to quantify mepolizumab's effects on the mentioned parameters, identify clinical variables influencing the degree of response to treatment, and portray responder and nonresponder patients. Methods: A multicentric retrospective no-profit observational study on severe asthmatic patients, treated with mepolizumab, and comorbid CRSwNP was conducted. All patients were followed for at least 12 months. SNOT-22 score, NP score, and blood eosinophil count (and other CRS-specific variables) were collected at baseline and after 12 months. Results: Forty-three patients were included. A statistically significant reduction was observed for SNOT-22 score (mean t0 SNOT-22 54.8 +/- 25.9; mean t12 SNOT-22 31.5 +/- 21.3, p < 0.0001), NP score (median t0 NPS 3 (IQR 3); median t12 NPS 2 (IQR 4), p < 0.0001), and blood eosinophil count (mean t0 blood eosinophils 804.7 +/- 461.5 cell/mu L; mean t12 blood eosinophils 107.5 +/- 104.6 cell/mu L, p < 0.0001) after 12 months of treatment. Twenty patients (47%) gained improvement both in clinical and endoscopic outcome. Mepolizumab responder patients presented a t0 SNOT-22 significantly higher than nonresponders (p = 0.0011). Conclusions: Mepolizumab improved CRSwNP outcomes in a population of severe asthmatic patients. No clinical feature emerged to outline the profile of a "typical" responder patient, except for baseline SNOT-22 score, which seemed to affect the response to treatment. Further studies would be necessary to supplement these preliminary evaluations
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