Surface roughness measurement is an integral part of the characterization of microtextured surfaces. Multiple established software packages offer the calculation of roughness parameters according to ISO 25178. However, these packages lack a specific set of features, which we hope to address in this work.
View Article and Find Full Text PDFBackground & Aims: The underlying mechanisms and clinical impact of portal microthrombosis in severe COVID-19 are unknown. Intrapulmonary vascular dilation (IPVD)-related hypoxia has been described in severe liver diseases. We hypothesised that portal microthrombosis is associated with IPVD and fatal respiratory failure in COVID-19.
View Article and Find Full Text PDFDirect Laser Interference Patterning (DLIP) stands out as a versatile and cost-effective method for functionalizing material surfaces at high throughputs. Monitoring the dynamics of the structure formation can lead to a deeper understanding of the interplay between the main factors governing the process and ultimately to optimize the final texture. Here, the formation of gratings on stainless steel by DLIP with ns-pulses is studied using a diffraction-based approach, which measures the time-resolved reflectivity (TRR) of the sample.
View Article and Find Full Text PDFBoron doping of diamond-like carbon coatings has multiple effects on their tribological properties. While boron typically reduces wear in cutting applications, some B-doped coatings show poor tribological performance compared with undoped films. This is the case of the tribological tests presented in this work in which an alumina ball is placed in frictional contact with different undoped and B-doped amorphous carbon coatings in humid air.
View Article and Find Full Text PDFThe nucleation of bubbles on solid surfaces is an important phenomenon in nature and technological processes like electrolysis. During proton-exchange membrane electrolysis, the nucleation and separation of the electrically nonconductive oxygen in the anodic cycle plays a crucial role to minimize the overpotential it causes in the system. This increases the efficiency of the process, making renewable energy sources and the "power-to-gas" strategy more viable.
View Article and Find Full Text PDFWith the increasing processing power of micro-electronic components and increasing spatial limitations, ensuring sufficient heat dissipation has become a crucial task. This work presents a microscopic approach to increasing the surface area through periodic surface structures. Microstructures with a periodic distance of 8.
View Article and Find Full Text PDFA route to increase the efficiency of thin film solar cells is improving the light-trapping capacity by texturing the top Transparent Conductive Oxide (TCO) so that the sunlight reaching the solar absorber scatters into multiple directions. In this study, Indium Tin Oxide (ITO) thin films are treated by infrared sub-picosecond Direct Laser Interference Patterning (DLIP) to modify the surface topography. Surface analysis by scanning electron microscopy and confocal microscopy reveals the presence of periodic microchannels with a spatial period of 5 µm and an average height between 15 and 450 nm decorated with Laser-Induced Periodic Surface Structures (LIPSS) in the direction parallel to the microchannels.
View Article and Find Full Text PDFSurface modification of yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) using lasers for adhesion enhancement with resin-matrix cement has been increasingly explored. However, Y-TZP is chemically inert and non-reactive, demanding surface modification using alternative approaches to enhance its bond strength to resin-matrix cements. The main aim of this study was to conduct an integrative review on the influence of ultrashort pulse laser patterning of zirconia (3Y-TZP) for enhanced bonding to resin-matrix cements.
View Article and Find Full Text PDFEmerging manufacturing technologies make it possible to design the morphology of electrocatalysts on the nanoscale in order to improve their efficiency in electrolysis processes. The current work investigates the effects of electrode-attached hydrogen bubbles on the performance of electrodes depending on their surface morphology and wettability. Ni-based electrocatalysts with hydrophilic and hydrophobic nanostructures are manufactured by electrodeposition, and their surface properties are characterized.
View Article and Find Full Text PDFSurface structuring using nano-second lasers can be used to enhance certain properties of a material or even to introduce new ones. One way to create these structures efficiently is direct laser interference patterning using different polarization vector orientations of the interfering beams. However, experimentally measuring the fabrication process of these structures is very challenging due to small length and time scales.
View Article and Find Full Text PDFGraphene oxide (GO) and reduced graphene oxide have outstanding qualities that could be exploited as reinforcement and antibacterial agents in a plethora of biomedical applications. In this contribution, it is reported the deployment of a polyacrylamide GO-hydrogel composite (GO@pAAm) which was photo-converted and structured by ultra-short laser irradiation using a direct laser writing (DLW) approach. The materials were characterized by Fourier Transform Infrared spectroscopy, scanning electron microscopy and confocal microscopy.
View Article and Find Full Text PDFIn times of societal development, sustainability has become a major concern for many manufacturers in the metal industries. In this context, surface texturing of cutting tools offers a promising approach in terms of reducing energy consumption and material waste. In this work, direct laser interference patterning is utilized for producing periodic line-like structures with spatial periods of 2.
View Article and Find Full Text PDFThe combination of direct laser interference patterning (DLIP) with laser-induced periodic surface structures (LIPSS) enables the fabrication of functional surfaces reported for a wide spectrum of materials. The process throughput is usually increased by applying higher average laser powers. However, this causes heat accumulation impacting the roughness and shape of produced surface patterns.
View Article and Find Full Text PDFIn recent years, the demand for highly integrated and lightweight components has been rising sharply, especially in plastics processing. One strategy for weight-saving solutions is the development of conductive tracks and layouts directly on the polymer housing parts in order to be able to dispense with the system integration of additional printed circuit boards (PCB). This can be conducted very advantageously and flexibly with laser-based processes for functionalizing polymer surfaces.
View Article and Find Full Text PDFAim/hypothesis: To compare the frequency of diabetic ketoacidosis (DKA) at diagnosis of type 1 diabetes in Italy during the COVID-19 pandemic in 2020 with the frequency of DKA during 2017-2019.
Methods: Forty-seven pediatric diabetes centers caring for >90% of young people with diabetes in Italy recruited 4,237 newly diagnosed children with type 1 diabetes between 2017 and 2020 in a longitudinal study. Four subperiods in 2020 were defined based on government-imposed containment measures for COVID-19, and the frequencies of DKA and severe DKA compared with the same periods in 2017-2019.
Triboscopy focuses on the analysis of the temporal evolution of a tribological system, combining local and time-resolved information, most commonly the evolution of friction. In this work, this technique is applied on measurements, which were carried out with a custom-built ultra-high vacuum tribometer in ball-on-disc configuration. Based on these experiments, an extended classification to distinguish different triboscopic features is suggested, depending on the persistence in both track position and time: Uniform, Global, Local, and Sporadic.
View Article and Find Full Text PDFVacuum environments provide challenging conditions for tribological systems. MoS2 is one of the materials commonly known to provide low friction for both ambient and vacuum conditions. However, it also exhibits poor wear resistance and low ability to withstand higher contact pressures.
View Article and Find Full Text PDFUniform periodic microstructure formation over large areas is generally challenging in Direct Laser Interference Patterning (DLIP) due to the Gaussian laser beam intensity distribution inherent to most commercial laser sources. In this work, a diffractive fundamental beam-mode shaper (FBS) element is implemented in a four-beam DLIP optical setup to generate a square-shaped top-hat intensity distribution in the interference volume. The interference patterns produced by a standard configuration and the developed setup are measured and compared.
View Article and Find Full Text PDFUnlabelled: In the last few decades, many studies have reported an increasing global incidence of type 1 diabetes. Studies on migrant populations have underlined the importance of both environmental and genetic factors.
Aims: Evaluate the incidence of type 1 diabetes in North African vs Italian children aged 0-14 years from 1 January 2015, to 31st December 2018, in Emilia-Romagna region, Italy.
Direct laser interference patterning (DLIP) is a laser-based surface structuring method that stands out for its high throughput, flexibility and resolution for laboratory and industrial manufacturing. This top-down technique relies on the formation of an interference pattern by overlapping multiple laser beams onto the sample surface and thus producing a periodic texture by melting and/or ablating the material. Driven by the large industrial sectors, DLIP has been extensively used in the last decades to functionalize metallic surfaces, such as steel, aluminium, copper or nickel.
View Article and Find Full Text PDFNonalcoholic fatty liver disease (NAFLD) is the most prevalent liver disease worldwide, and affects 25% of the population in Western countries. NAFLD is the hepatic manifestation of the metabolic syndrome, linked to insulin resistance, which is the common pathogenetic mechanism. In approximately 40% of NAFLD patients, steatosis is associated with necro-inflammation and fibrosis, resulting in nonalcoholic steatohepatitis (NASH), a severe condition that may progress to cirrhosis and liver cancer.
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