Photosensitive Control and Network Synchronization of Chemical Oscillators.

The Belousov-Zhabotinsky (BZ) reaction has long been a paradigmatic system for studying chemical oscillations. Here, we experimentally studied the synchronization control within photochemically coupled star networks of BZ oscillators. Experiments were carried out in wells performed in soda-lime glass constructed using novel laser technologies. Utilizing the inherent oscillatory nature of the BZ reaction, we engineered a star network of oscillators interconnected through photochemical inhibitory coupling. Furthermore, the experimental setup presented here could be extrapolated to more complex network architectures with both excitatory and inhibitory couplings, contributing to the fundamental understanding of synchronization in complex systems.

Synergism between obesity and HFpEF on neutrophils phenotype and its regulation by adipose tissue-molecules and SGLT2i dapagliflozin.

The adiposity invokes innate immune activity, coronary microvascular dysfunction and consequently heart failure preserved ejection fraction (HFpEF). Our aim was to study the neutrophils profile on obesity and cardiovascular disease and its regulation by adipose tissue-secretome and dapagliflozin. We have isolated neutrophils from patients undergoing open heart surgery (19 women and 51 men). Its migration activity was performed with culture-transwell, transcriptional studies of proteolytic enzymes, adhesion molecules or receptors were analysed by real-time PCR and proteomics (from 20 patients) analysis by TripleTOF mass spectrometer. Differentiated HL-60 (dHL-60) was used as a preclinical model on microfluidic for endothelial cells attaching assays and genes regulation with epicardial and subcutaneous fat secretomes from patients (3 women and 9 men) or dapagliflozin 1-10 µM treatments. The transcriptional and proteomics studies have determined higher levels of adhesion molecules in neutrophils from patients with obesity. The adhesion molecule CD11b levels were higher in those patients with the combined obesity and HFpEF factors (1.70 ± 0.06 a.u. without obesity, 1.72 ± 0.04 a.u. obesity or HFpEF without obesity and 1.79 ± 0.08 a.u. obesity and HFpEF; p < .01). While fat-secretome induces its upregulation, dapagliflozin can modulated it. Because CD11b upregulation is associated with higher neutrophils migration and adhesion into endothelial cells, dapagliflozin might modulate this mechanism on patients with obesity and HFpEF.

UV light dosage distribution over irregular respirator surfaces. Methods and implications for safety.

The SARS-CoV-2 pandemic has led to a global decrease in personal protective equipment (PPE), especially filtering facepiece respirators (FFRs). Ultraviolet-C wavelength is a promising way of decontamination, however adequate dosimetry is needed to ensure balance between over and underexposed areas and provide reliable results. Our study demonstrates that UVGI light irradiance varies significantly on different respirator angles and propose a method to decontaminate several masks at once ensuring appropriate dosage in shaded zones. An UVGI irradiator was built with internal dimensions of 69.5 × 55 × 33 cm with three 15 W UV lamps. Inside, a grating of 58 × 41 × 15 cm was placed to hold the masks. Two different flat fold respirator models were used to assess irradiance, four of model Aura 9322 3 M of dimensions 17 × 9 × 4 cm (tri-fold), and two of model SAFE 231FFP3NR (bi-fold) with dimensions 17 × 6 × 5 cm. An STN-SilverNova spectrometer was employed to verify wavelength spectrum and surface irradiance. A simulation was performed to find the irradiance pattern inside the box and the six masks placed inside. These simulations were carried out using the software DIALUX EVO 8.2. The data obtained reveal that the irradiance received inside the manufactured UVGI-irradiator depends not only on the distance between the lamps' plane and the base of the respirators but also on the orientation and shape of the masks. This point becomes relevant to assure that all the respirators inside the chamber receive the correct dosage. Irradiance over FFR surfaces depend on several factors such as distance and angle of incidence of the light source. Careful irradiance measurement and simulation can ensure reliable dosage in the whole mask surface, balancing overexposure. Closed box systems might provide a more reliable, reproducible UVGI dosage than open settings.

Laser-based surface multistructuring using optical elements and the Talbot effect.

We present a laser based technique combined with the Talbot effect for microstructuring surfaces. The use of the Talbot effect is introduced as a solution to avoid damage of the periodic object used for micropattering different surfaces during the ablation process. The fabrication of two periodic objects (a mask and a microlens array) for micropattering surfaces and the identification of their Talbot planes is presented. A metal foil is ablated at distances corresponding to selected Talbot planes of the periodic objects. The setup allows us to design the desired pattern and the result is a multistructured surface with a high number of identical microholes, achieving a minimum diameter around 4µm. The different aspect of the periodic object working in direct contact and working at these Talbot distances is shown. These pictures reveal the advantages of working of using Talbot effect for a rapid, repeatable and no-contaminant multistructuring. Some industrial applications are illustrated.

Single-pulse laser ablation threshold of borosilicate, fused silica, sapphire, and soda-lime glass for pulse widths of 500 fs, 10 ps, 20 ns.

In this work, we report a comparative study of the laser ablation threshold of borosilicate, fused silica, sapphire, and soda-lime glass as a function of the pulse width and for IR laser wavelengths. We determine the ablation threshold for three different pulse durations: τ=500 fs, 10 ps, and 20 ns. Experiments have been performed using a single laser pulse per shot in an ambient (air) environment. The results show a significant difference, of two orders of magnitude, between the group of ablation thresholds obtained for femtosecond, picosecond, and nanosecond pulses. This difference is reduced to 1 order of magnitude in the soda-lime substrate with tin impurities, pointing out the importance of the incubation effect. The morphology of the marks generated over the different glass materials by one single pulse of different pulse durations has been analyzed using a scanning electron microscope (FESEM ULTRA Plus). Our results are important for practical purposes, providing the ablation threshold data of four commonly used substrates at three different pulse durations in the infrared regime (1030-1064 nm) and complete data for increasing the understanding of the differences in the mechanism's leading ablation in the nanosecond, picosecond, and femtosecond regimes.

Fluence ablation threshold dependence on tin impurities in commercial soda-lime glass.

In this paper, we study the reduction in the fluence ablation threshold induced by tin impurities incorporated in float soda-lime glass during the fabrication process. The laser system used in the experiments was a Nd:YVO4 laser operating at 1064 nm with a pulse duration of 20 ns. The fluence ablation thresholds found were 112 J/cm2 for the tin side and 920 J/cm2 for the tin-free side, which means a reduction of nearly 1 order of magnitude. The fluence ablation threshold reduction permits the manufacturing of narrower grooves with small level of roughness, obtaining quality elements in low-cost soda-lime substrates.

Biocompatibility Testing of UV-Curable Polydimethylsiloxane for Human Umbilical Vein Endothelial Cell Culture on-a-Chip.

Polydimethylsiloxane (PDMS) is extensively used to fabricate biocompatible microfluidic systems due to its favorable properties for cell culture. Recently, ultraviolet-curable PDMS (UV-PDMS) has shown potential for enhancing manufacturing processes and final optical quality while retaining the benefits of traditional thermally cured PDMS. This study investigates the biocompatibility of UV-PDMS under static and flow conditions using human umbilical vein endothelial cells (HUVECs). UV-PDMS samples were treated with oxygen plasma and boiling deionized water to assess potential improvements in cell behavior compared with untreated samples. We evaluated HUVECs adhesion, growth, morphology, and viability in static cultures and microchannels fabricated with UV-PDMS to test their resistance to flow conditions. Our results confirmed the biocompatibility of UV-PDMS for HUVECs culture. Moreover, plasma-oxygen-treated UV-PDMS substrates exhibited superior cell growth and adhesion compared to untreated UV-PDMS. This enhancement enabled HUVECs to maintain their morphology and viability under flow conditions in UV-PDMS microchannels. Additionally, UV-PDMS demonstrated improved optical quality and more efficient handling and processing, characterized by shorter curing times and simplified procedures utilizing UV light compared to traditional PDMS.

Impact of Enhanced Phagocytosis of Glycated Erythrocytes on Human Endothelial Cell Functions.

Diabetes is associated with a high mortality rate due to vascular complications. Chronic hyperglycemia in diabetes leads to enhanced oxidative stress and glycation. Here, we explored the impact of glycation on human erythrocyte characteristics and capacity to affect endothelial cell function following erythrophagocytosis. Native and glucose-mediated glycated erythrocytes were prepared and characterized in terms of structural and deformability modifications. Erythrocyte preparations were tested for their binding and phagocytosis capacity as well as the potential functional consequences on human endothelial cell lines and primary cultures. Oxidative modifications were found to be enhanced in glycated erythrocytes after determination of their deformability, advanced glycation end-product content and eryptosis. Erythrophagocytosis by endothelial cells was significantly increased when incubated in the presence of glycated erythrocytes. In addition, higher iron accumulation, oxidative stress and impaired endothelial cell permeability were evidenced in cells previously incubated with glycated erythrocytes. When cultured under flow conditions, cellular integrity was disrupted by glycated erythrocytes at microvessel bifurcations, areas particularly prone to vascular complications. This study provides important new data on the impact of glycation on the structure of erythrocytes and their ability to alter endothelial cell function. Increased erythrophagocytosis may have a deleterious impact on endothelial cell function with adverse consequences on diabetic vascular complications.

Microfluidic devices manufacturing with a stereolithographic printer for biological applications.

Stereolithographic printers have revolutionized many manufacturing processes with their capacity to easily produce highly detailed structures. In the field of microfluidics, this technique avoids the use of complex steps and equipment of the conventional technologies. The potential of low force stereolithography technology is analysed for the first time using a Form 3B printer and seven printing resins through the fabrication of microchannels and pillars. Manufacturing performance of internal and superficial channels and pillars is studied for the seven printing resins in different configurations. A complete characterization of printed structures is carried out by optical, confocal and SEM microscopy, and EDX analysis. Internal channels with unobstructed lumen are obtained for diameters and angles greater than 500 µm and 60°, respectively. Outward and inward superficial channels in the range of hundreds of microns can be fabricated with an accurate profile, printing them with a perpendicular orientation respect to the base, allowing a proper uncured resin evacuation. Outward channels are replicated by soft lithography using polydimethylsiloxane. Clear, Model and Tough resins show a good behaviour to be used as master, but Amber and Dental resins present a poor topology transference from the master to the replica. According to the needs of devices used for biological and biomedical research, transparency as well as superficial biocompatibility of some resins is evaluated. Human umbilical vein endothelial cells (HUVEC) adhesion is confirmed on Amber, Dental and Clear resins, but these cells were only able to grow and progress as a cell culture over the Amber resin. Therefore, Amber showed an adequate biocompatibility, in terms of cell adhesion and growth for HUVEC.

Haemodynamic-dependent arrest of circulating tumour cells at large blood vessel bifurcations as new model for metastasis.

Homing of circulating tumour cells (CTC) at distant sites represents a critical event in metastasis dissemination. In addition to physical entrapment, probably responsible of the majority of the homing events, the vascular system provides with geometrical factors that govern the flow biomechanics and impact on the fate of the CTC. Here we mathematically explored the distribution of velocities and the corresponding streamlines at the bifurcations of large blood vessel and characterized an area of low-velocity at the carina of bifurcation that favours the residence of CTC. In addition to this fluid physics effect, the adhesive capabilities of the CTC provide with a biological competitive advantage resulting in a marginal but systematic arrest as evidenced by dynamic in vitro recirculation in Y-microchannels and by perfusion in in vivo mice models. Our results also demonstrate that viscosity, as a main determinant of the Reynolds number that define flow biomechanics, may be modulated to limit or impair CTC accumulation at the bifurcation of blood vessels, in agreement with the apparent positive effect observed in the clinical setting by anticoagulants in advanced oncology disease.

Radio-frequency spectrum analysis of a jittery train after a second-order dispersive Talbot line.

The power spectral density of the intensity of coherent Gaussian pulse trains suffering timing jitter after a dispersive line with arbitrary first- (beta(2)) and second-order (beta(3)) dispersion is computed in the small-signal approximation. Due to timing jitter noise, the initial radio-frequency spectrum shows noise bands whose bandwidth and position depend, respectively, on the jitter's standard deviation and on the jitter's pulse-to-pulse correlation. After setting the accumulated first-order dispersion to Talbot conditions, it is shown that the influence on the noise spectrum is a multiplicative factor with a multiple-bandpass structure. This factor depends on both the dispersive characteristics of the line and the pulse parameters, but not on the timing jitter's correlation properties, and represents the filtering mechanism responsible for Talbot repetition-rate multiplication. It is shown that the integer or fractional temporal Talbot effect does not worsen the timing properties of the initial train. In addition, and depending on the type of jitter correlation, the pulse width, and the total dispersion, it is shown that the temporal Talbot effect may lead to significant jitter reduction. The theory is exemplified by use of simulations. The applicability of the model to practical situations is also analyzed.

A laser-based technology for fabricating a soda-lime glass based microfluidic device for circulating tumour cell capture.

We developed a laser-based technique for fabricating microfluidic microchips on soda-lime glass substrates. The proposed methodology combines a laser direct writing, as a manufacturing tool for the fabrication of the microfluidics structures, followed by a post-thermal treatment with a CO2 laser. This treatment will allow reshaping and improving the morphological (roughness) and optical qualities (transparency) of the generated microfluidics structures. The use of lasers commonly implemented for material processing makes this technique highly competitive when compared with other glass microstructuring approaches. The manufactured chips were tested with tumour cells (Hec 1A) after being functionalized with an epithelial cell adhesion molecule (EpCAM) antibody coating. Cells were successfully arrested on the pillars after being flown through the device giving our technology a translational application in the field of cancer research.

Temporal zone plate.

This paper extends the investigation of zone plates to the temporal case. By exploiting the space-time duality between the paraxial diffraction of beams in space and the linear dispersion of optical pulses, we present the time-domain analog of a multiple imaging system. The temporal system is created by using a digital chirp signal generator together with two dispersive delay lines. The key motivation is the potential application of the temporal zone plate to multiple compressions of pulses in dispersive lines.

Talbot conditions, Talbot resonators, and first-order systems.

A study of first-order Talbot resonators is presented. The general conditions for Talbot effect in ABCD systems are determined. These conditions are applied to the computation of the diffraction overlapping coefficients between array Gaussian emitters in a general first-order Talbot resonator. Relations on the ray-transfer matrix to generate the symmetric and the totally antisymmetric supermodes of the array are derived. These relations generalize the free-space, round-trip lengths of 1/2 and 1/4 of the Talbot distance. A new type of resonator based on a plano-convex gradient-index rod is proposed.