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Tailored ZnO surface functionalization was performed inside a polydimethyl-siloxane (PDMS) microchannel of a micro-optofluidic device (mofd) to modulate its surface hydrophobicity to develop a method for fine tuning the fluid dynamics inside a microchannel. The wetting behavior of the surface is of particular importance if two different phases are used for system operations. Therefore, the fluid dynamic behavior of two immiscible fluids, (i) air–water and (ii) air–glycerol/water in PDMS mofds and ZnO-PDMS mofds was investigated by using different experimental conditions. The results showed that air–glycerol/water fluid was always faster than air–water flow, despite the microchannel treatment: however, in the presence of ZnO microstructures, the velocity of the air–glycerol/water fluid decreased compared with that observed for the air–water fluid. This behavior was associated with the strong ability of glycerol to create an H-bond network with the exposed surface of the zinc oxide microparticles. The results presented in this paper allow an understanding of the role of ZnO functionalization, which allows control of the microfluidic two-phase flow using different liquids that undergo different chemical interactions with the surface chemical terminations of the microchannel. This chemical approach is proposed as a control strategy that is easily adaptable for any embedded micro-device.

Microscale optofluidic devices are a category of microscale devices combining fluidic and optical features. These devices typically enable in-situ fluid flow measurement for pharmaceutical, environmental or biomedical applications. In micro-optofluidic devices, in order to deliver, as close as possible, the input light to the sample or a specific chip section and, collect the output signal, it is necessary to miniaturize optical components. In this paper, two low-cost technologies, 3D Printing PDMS-based and laser cutting PMMA-based (PDMS stands for Poly-dimethyl-siloxane and PMMA for Poly-methyl-methacrylate), were investigated as novel methods to realize micro-optical waveguides (μWGs) comparing their performances. An ad-hoc master-slave protocol developed to realize PDMS components by 3D Printing has been fully optimized. The manufacturing technologies proposed require simple and low-cost equipment and no strictly controlled environment. Similar results are obtained for both the micro-optical waveguides realized. Their losses, disregarding the losses caused by the fibers’ alignment and the miss-match of the geometry with the waveguide, are of the order of 20%, almost equivalent for both approaches (PDMS-μWG and PMMA-μWG). The losses are of the order of 10% when the PDMS-μWG is shielded by a copper layer, with a significant improvement of the signal acquired. The results obtained show the possibility of using the two low-cost technologies presented for the realization of micro-optical waveguides suitable to be integrated in micro-optofluidic devices and the potential of creating micro-optical paths inside micro-embedded systems.

In this work, the use of projection micro-stereolithography (PμSL) to 3D print a micro-optofluidic device for slug flow detection is presented. For comparison purposes, a poly-dimethylsiloxane (PDMS)–based device was also manufactured by a novel master–slave 3D printing approach. The micro-optofluidic device has a microfluidic T-junction with a micro-optical section that consists of two optical fiber insertions used for slug flow detection. The design of the device also includes two micro-channels for the optical fiber’s insertion, needed to acquire a light signal, which give a direct information about the microfluidic channel inner flow by exploiting the absorption phenomenon. The working principle in the detection is based on a different light transmission correlated to the fluid interfering with the laser beam in a micro-channel section. The two materials used for the two manufacturing approaches were fully characterized in terms of their surface properties via both Atomic Force Microscopy (AFM) and angle of contact measure.The process within the two micro-channels was monitored optically and a signal correlated to the slug passage was analyzed for the flow tracking. A wide experimental campaign was done for the device manufactured through the PμSL technique in different operative conditions. Thus, the optimal one was identified through the Analysis of Variance (ANOVA). Then, a detailed comparison between the slug process detected inside the HTL resin device and the PDMS device was carried out to evaluate the pros and cons of using different materials and fabrication techniques. The analysis run on the two devices revealed that the HTL resin device can be used for slug flow detection, but future research is still needed to obtain a resin allowing to outperform the PDMS device.

In this work, the use of Projection Micro Stereolithography (PmSL) to 3D print a micro-optofluidic device for two-phase slug flow detection is presented. For comparison purposes a PDMS based device obtained by casting was also manufactured. The micro-optofluidic device has a microfluidic T-junction with a micro-optical section that consists of two optical fiber insertions used for two-phase slug flow detection. The working principle in the detection is based on a different light transmission correlated to the fluid interfering with the laser beam in a micro-channel section. The 3D printed material is fully characterized in terms of its surface properties and compared to PDMS used for standard construction using a master-slave casting procedure. The two devices were tested after the setup parameters for the detection were optimized using ANOVA for the 3D printed device. The comparisons of the two devices revealed that 3D printed device can be used for two-phase slug flow detection but future research is still need to obtain a 3D printed resin allowing to outperform PDMS.

In this work, it is presented a micro-optofluidic flow detector used for on-chip biological and chemical samples investigation. It is made in Poly-dimethyl-siloxane using a master-slave approach based on the 3D-Printing techniques. The micro-optofluidic device is made by assembling a microfluidic T-junction with a micro-optical section that consists of two optical fiber insertions and a PDMS gold-spattered micro-waveguide. The working principle in the detection is based on a different light transmission correlated to the fluid interfering with the laser beam in a micro-channel section. The proposed solution allows to realize a PDMS micro-device taking the advantage of 3D- Printing and goes beyond the restriction in the material selection. The device's performances were tested in the fluids detection and in the evaluation of the cell concentrations. Additionally, the micro-device was used as a real-time two-phase fluids flow detector. The two-phases flows were successfully monitored in different experimental conditions, varying both hydrodynamic and optical external stimuli.

In the recent years, two-phase microfluidics has contributed to various scientific areas such as chemistry, biology and medicine. In particular, two-phase flows, obtained from two immiscible fluids or a mix of fluid and microparticles, gained attention for their possible application in implementing logic gates and programmable devices. Moreover, their behavior in networks of microchannels is still not well studied, even if some experimental results are presented in literature but far from well-established framework that can drive to the flow control. Recently, the dynamics of two-phase microfluidic setups has been characterized by means of chaos synchronization obtaining a behavioral model of the bubble flow. Starting from these results, in this contribution the possibility to model the bubble flow behavior in a two-phase microfluidic with a simple nonlinear two-element circuit composed by a capacitor and a memristive device. The circuit is able to synchronize its dynamics to the microfluidic setup behavior, therefore acting as a qualitative sensor of the hydrodynamic regime.

To identify neuroanatomical abnormalities in the brains of people with psychosis, schizophrenia or children experiencing PLEs have been detected atypical activity levels in specific brain regions using fMRI or event-related potentials analysis. Both of these approaches suffer from drawbacks. In this study using EEG signals, the method implemented surpasses the limitations of both. The proposed method combines advanced signal processing, in time and frequency domain, with graph analysis and evaluates the inference across subjects. The first part of the procedure consists of a data preparation phase and of a data analysis phase, based on functional connectivity evaluation using the peak correlation methods. The second part takes into account parametric and topological aspects of the brain network, extracted by the brain connectivity and the graph analysis, obtaining robust and clinically relevant information.

Objectives The negative effects of malnutrition on the prognosis of hospitalized patients are well documented; however, less known is the awareness and knowledge of health care professionals about this complication. The aim of this study was to evaluate the trend of the requests for nutritional consultation in years and the prescription of artificial nutrition (AN), for adult patients at a university hospital in southern Italy in the years 2004, 2008, 2012, and 2016 to assess the progress of medical teams concerning awareness of hospital malnutrition. Methods This was a retrospective study that evaluated the time trend of nutritional consultation requests and related prescription of AN, for adult patients at a university hospital in southern Italy in the years 2004, 2008, 2012, and 2016. Of 112 233 inpatients, 2505 received a nutritional consultation with the prescription of AN. Results The number of patients on AN increased from 507 of 33 240 (1.52%) in 2004 to 730 of 29 195 (2.5%) in 2008 (P The request for AN was quite equally distributed between surgical (51.5%) and medical wards (48.5%), with a prevalence among patients with oncologic diseases (806 patients [65.6%]). As for nononcologic diseases, 20.4% involved the gastrointestinal tract and 6.3% the nervous system. Throughout the 12 y of observation, parenteral nutrition was the main prescribed support (59.8%) followed by oral nutritional supplements (26.1%) and enteral nutrition (9.3%). Mean nutritional intervention duration was 11 d (±10.8 d). Conclusions The request of AN for hospitalized patients increased over time, probably owing to improved medical consciousness of the potential risks for malnutrition and the availability of a specialized clinical nutrition team.