184 research outputs found
The ambitious role of anti angiogenesis molecules: Turning a cold tumor into a hot one
In renal cancer emerging treatment options are becoming available and there is a strong need to combine therapies to reformulate and adjourn clinical practice. We here highlight and discuss the need to take advantage of the common immune targets to design combined strategies to increase clinical responses
A microfluidic method for passive trapping of sperms in microstructures
Sperm motility is a prerequisite for male fertility. Enhancing the concentration of motile sperms in assisted reproductive technologies - for human and animal reproduction - is typically achieved through aggressive methods such as centrifugation. Here, we propose a passive technique for the amplification of motile sperm concentration, with no externally imposed forces or flows. The technique is based on the disparity between probability rates, for motile cells, of entering and escaping from complex structures. The effectiveness of the technique is demonstrated in microfluidic experiments with microstructured devices, comparing the trapping power in different geometries. In these micro-traps, we observe an enhancement of cells' concentration close to 10, with a contrast between motile and non-motile cells increased by a similar factor. Simulations of suitable interacting model sperms in realistic geometries reproduce quantitatively the experimental results, extend the range of observations and highlight the components that are key to the optimal trap design
Environmentally Friendly Method of Assembly of Cardanol and Cholesterol into Nanostructures Using a Continuous Flow Microfluidic Device
This study shows a viable and straightforward microfluidic method of assembly of cardanol (CA) and cholesterol (CH) into amphiphile nanostructures obtained through a hydrodynamic focusing approach according to which an alcoholic solution of CA and CH is constrained within a two-dimensional lamina shape by two lateral streams of borate buffer solution. The process is performed within glass-made cross-shaped micro-sized fluidic chips specially designed to achieve a laminar regime. CA, distilled from the cashew nut shell liquid, is demonstrated as a surface-active molecule in borate buffer basic medium and when mixed with CH it produces versatile nanovesicles through an in-batch solvent-free process. Compared to this conventional method, the microfluidic route allows operating under continuous flows, with a reduced amount of reagents and at lower experimental temperatures, ensuring no waste formation and the achievement of size-monodisperse amphiphile nanostructures that do not need further steps of purification. Electron microscopy analyses demonstrate that upon increasing CH in the lipid mixture, a switchover from spherical CA micelles to CA/CH mixed closed vesicles occurs. Differential scanning microcalorimetry confirms the formation of vesicular structures and evidences the primary role of CH, which increasingly lowers the temperature of transition depending on its concentration
Mixing enhancement induced by viscoelastic micromotors in microfluidic platforms
Fine manipulation of fluid flows at the microscale has a tremendous impact on mass transport phenomena of chemical and biological processes inside microfluidic platforms. Fluid mixing in the laminar flow regime at low Reynolds number is poorly effective due to the inherently slow diffusive mechanism. As a strategy to enhance mixing and prompt mass transport, here, we focus on polyelectrolyte multilayer capsules (PMCs), embodying a catalytic polyoxometalate, as microobjects to create elastic turbulence and as micromotors to generate chaotic flows by fuel-fed propulsions. The effects of the elastic turbolence and of the artificial propulsion on some basic flow parameters, such as pressure and volumetric flow rate, are studied by a microfluidic set-up including pressure and flow sensors. Numerical-handling and physical models of the experimental data are presented and discussed to explain the measured dependence of the pressure drop on the flow rate in presence of the PMCs. As a practical outcome of the study, a strong decrease of the mixing time in a serpentine microreactor is demonstrated. Unlike our previous reports dealing with capillarity flow studies, the present paper relies on hydrodynamic pumping experiments, that allow us to both develop a theoretical model for the understanding of the involved phenomena and demonstrate a successful microfluidic mixing application. All of this is relevant in the perspective of developing microobject-based methods to overcome microscale processes purely dominated by diffusion with potential improvements of mass trasport in microfluidic platforms. \ua9 2019 Elsevier B.V
Catalytic oxygen production mediated by smart capsules to modulate elastic turbulence under a laminar flow regime
none11Liquid flow in microchannels is completely laminar and uniaxial, with a very low Reynolds number regime and long mixing lengths. To increase fluid mixing and solubility of reactants, as well as to reduce reaction time, complex three-dimensional networks inducing chaotic advection have to be designed. Alternatively, turbulence in the liquid can be generated by active mixing methods (magnetic, acoustic waves, etc.) or adding small quantities of elastic materials to the working liquid. Here, polyelectrolyte multilayer capsules embodying a catalytic polyoxometalate complex have been suspended in an aqueous solution and used to create elastic turbulence and to propel fluids inside microchannels as an alternative to viscoelastic polymers. The overall effect is enhanced and controlled by feeding the polyoxometalate-modified capsules with hydrogen peroxide, H2O2, thus triggering an on-demand propulsion due to oxygen evolution resulting from H2O2 decomposition. The quantification of the process is done by analysing some structural parameters of motion such as speed, pressure, viscosity, and Reynolds and Weissenberg numbers, directly obtained from the capillary dynamics of the aqueous mixtures with different concentrations of H2O2. The increases in fluid speed as well as the capsule-induced turbulence effects are proportional to the H2O2 added and therefore dependent on the kinetics of H2O2 dismutation.Zizzari A.; Bianco M.; Miglietta R.; del Mercato L. L.; Carraro M.; Soraru A.; Bonchio M.; Gigli G.; Rinaldi R.; Viola I.; Arima, V.Zizzari, A.; Bianco, M.; Miglietta, R.; del Mercato, L. L.; Carraro, M.; Soraru, A.; Bonchio, M.; Gigli, Giuseppe; Rinaldi, Rosaria; Viola, I.; Arima, V
Nitric Oxide-mediated cytotoxic effect induced by zoledronic acid treatment on Human Gingival Fibroblasts
Zoledronic acid (ZA) belongs to bisphosphonates (BPs), drugs administered to treat resorptive bone diseases. Although ZA is largely used in the clinical practice, significant adverse effects of ZA, such as osteonecrosis of the jaw (ONJ), were recorded. The aim of this work was to evaluate the role of Nitric Oxide (NO) in the in vitro response of Human Gingival Fibroblasts (HGFs) to 1, 5, 10 and 100ÎĽM ZA. HGFs morphology was evaluated through phase contrast microscopy and live/ dead staining; MTT and ELISA assays were applied to measure cell viability, Collagen Type I and IL6 secretion. ROS production and mitochondrial membrane potential were evaluated by flow cytometry; NO production and NOS activity by spectrophotometric analysis; eNOS and nNOS expression by fluorescence microscopy. Viable fibroblasts are evidenced in control sample while floating dead cells and cells close to detachment phase in ZA treated sample along with decreased level of Collagen Type I. Control sample shows higher number of viable cells respect to ZA treated one and ROS production increases when ZA is added. Released NO in ZA treated sample appears higher and NO overproduction is related to increased nNOS activity. IL 6 secretion level is higher in ZA treated sample than in control one. Our results suggest ROS involvement in NO overproduction, due to nNOS recruitment, both at low and high doses. In turn, NO release seems to be able to trigger the inflammatory response only when high doses are administered
Effect of surface tension and drying time on inkjet-printed PEDOT:PSS for ITO-free OLED devices
Abstract Highly conductive PEDOT:PSS is one of the most promising materials for indium tin oxide (ITO) substitution in printed electronics. Here, we report the development and optimisation of two PEDOT:PSS ink formulations for the fabrication of inkjet-printed transparent conductive layers. Starting from aqueous commercial solutions, co-solvents and a non-ionic surfactant were employed to modify the surface tension, improve the wetting capability of the ink, and obtain uniform and homogeneous thin films. In particular, the quantities of ethanol and surfactant were systematically adjusted to determine the optimal conditions for inkjet printing. The results demonstrate that a surface tension value between 28 and 40 mN/m and approximately 40 vol.% of a low-boiling-point co-solvent are fundamental to ensure the proper wetting of the glass substrate and a quick-drying process that confers uniformity to the printed thin film. The printed PEDOT:PSS thin films show good morphological, optical, and electrical properties that are similar to those observed for the corresponding spin-coated layers. The organic light-emitting diodes (OLEDs) fabricated with the inkjet-printed PEDOT:PSS electrodes showed a maximum quantum efficiency of 5.5% and maximum current efficiency of 15 cd/A, which is comparable to spin-coated reference devices. These results demonstrate the great potential of polymeric electrodes for the fabrication of high-efficiency printed OLED devices that are compatible with flexible and stretchable substrates
Aesthetic Surgical Crown Lengthening Procedure
The aim of this case report was to describe the surgical sequence of crown lengthening to apically reposition the dentogingival complex, in addition to an esthetic restorative procedure. Many different causes can be responsible for short clinical crown. In these cases, the correct execution of a restorative or prosthetic rehabilitation requires an increasing of the crown length. According to the 2003 American Academy of Periodontology (Practice Profile Survey), crown lengthening is the most habitual surgical periodontal treatment
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