Ceramic MEMS Designed for Wireless Pressure Monitoring in the Industrial Environment

This paper presents the design of a wireless pressure-monitoring system for harsh-environment applications. Two types of ceramic pressure sensors made with a low-temperature cofired ceramic (LTCC) were considered. The first type is a piezoresistive strain gauge pressure sensor. The second type is a capacitive pressure sensor, which is based on changes of the capacitance values between two electrodes: one electrode is fixed and the other is movable under an applied pressure. The design was primarily focused on low power consumption. Reliable operation in the presence of disturbances, like electromagnetic interference, parasitic capacitances, etc., proved to be contradictory constraints. A piezoresistive ceramic pressure sensor with a high bridge impedance was chosen for use in a wireless pressure-monitoring system and an acceptable solution using energy-harvesting techniques has been achieved. The described solution allows for the integration of a sensor element with an energy harvester that has a printed thick-film battery and complete electronics in a single substrate packaged inside a compact housing

Trend of suicide by self-immolation in a 13-year timeline: was the COVID-19 pandemic a potentially important stressor?

IntroductionSelf-immolation is an uncommon way of attempting and committing a suicide, with a fatality rate of 80%. The risk factors in self-immolation victims vary depending on demographic characteristics, socio-economic and cultural factors as well as religious beliefs. Whether the COVID-19 pandemic was a potentially important stressor for self-immolation is still unknown, with insufficient studies examining this issue. Therefore, in this study, we aimed to examine the trend of self-immolation in a 13-year timeline, and the potential association of COVID-19 pandemic with the increase in the incidence and severity of self-immolation injuries in Serbia in 2021.Materials and methodsThe study included hospitalized patients due to intentional burns caused by self-immolation in the period from January 1, 2008 to December 31, 2021. Joinpoint regression analysis was used for the analysis of continuous linear trends of self-immolation cases with change points.ResultsWhile a rising trend was observed in the 2008–2013 time segment, followed by a decline in the upcoming 2013–2016 time segment, a significant increase reached its maximum during COVID-19 pandemic (2021), with annual percent change of 37.1% (p = 0.001). A significant increase in the median number of cases per year was observed during 2021 compared to the previous periods (7.5 vs. 2). Frequency of patients with a psychiatric diagnosis vs. those without a psychiatric diagnosis was significantly higher during than before the COVID-19 period (66.7 vs. 36.1%, p = 0.046).ConclusionIn our study, a significant increase in the frequency of suicide attempts by self-immolation during COVID-19 pandemic was noticed. There was also an increased frequency of pre-existing psychiatric illness among patients during the pandemic period. With limited high-quality data available, the study adds to a rising body of evidence for assessment of outcomes of the pandemic on mental health and recognition of stressors for self-immolation

Cancer Biomarker Discovery: The Entropic Hallmark

Background: It is a commonly accepted belief that cancer cells modify their transcriptional state during the progression of the disease. We propose that the progression of cancer cells towards malignant phenotypes can be efficiently tracked using high-throughput technologies that follow the gradual changes observed in the gene expression profiles by employing Shannon's mathematical theory of communication. Methods based on Information Theory can then quantify the divergence of cancer cells' transcriptional profiles from those of normally appearing cells of the originating tissues. The relevance of the proposed methods can be evaluated using microarray datasets available in the public domain but the method is in principle applicable to other high-throughput methods. Methodology/Principal Findings: Using melanoma and prostate cancer datasets we illustrate how it is possible to employ Shannon Entropy and the Jensen-Shannon divergence to trace the transcriptional changes progression of the disease. We establish how the variations of these two measures correlate with established biomarkers of cancer progression. The Information Theory measures allow us to identify novel biomarkers for both progressive and relatively more sudden transcriptional changes leading to malignant phenotypes. At the same time, the methodology was able to validate a large number of genes and processes that seem to be implicated in the progression of melanoma and prostate cancer. Conclusions/Significance: We thus present a quantitative guiding rule, a new unifying hallmark of cancer: the cancer cell's transcriptome changes lead to measurable observed transitions of Normalized Shannon Entropy values (as measured by high-throughput technologies). At the same time, tumor cells increment their divergence from the normal tissue profile increasing their disorder via creation of states that we might not directly measure. This unifying hallmark allows, via the the Jensen-Shannon divergence, to identify the arrow of time of the processes from the gene expression profiles, and helps to map the phenotypical and molecular hallmarks of specific cancer subtypes. The deep mathematical basis of the approach allows us to suggest that this principle is, hopefully, of general applicability for other diseases

Improving carbon nanotube nanodevices: Ambipolar field effect transistors and high -current interconnects

Early studies of electron transport in single-wall carbon nanotubes (SWNTs) have been hindered by large resistance of the nanotube-contact interface and weak electrostatic coupling to the gate electrode. Several groups have shown that the contact resistance can be reduced to kΩ range by growing nanotubes directly on the substrate using chemical vapor deposition (CVD). In our work we implement this growth technique by fabricating electrodes from cobalt, which creates perfectly transparent nanotube-electrode contacts, [special characters omitted] = 0.98. In addition, we use high temperature anneal in hydrogen atmosphere to reduce defect density in the dielectric layer and enhance gate effectiveness. At low temperatures we reduce the amount of gate voltage needed to add a single electron to 0.8 μm long nanotube by an order of magnitude to 15 mV. Using these improvements, we demonstrate ambipolar transport in nanotube-based field effect transistor (TubeFET), and use it to develop a novel type of memory device for data storage. In a metallic nanotube, we show that gate voltage can be used to tune the reflection probability of defect-induced scattering centers. Furthermore, total scattering probability increases with device length, suggesting weak scattering from molecular adsorbates. Studies of resistance in metallic nanotubes reveal both metallic and insulating temperature behaviors, depending on the total reflection probability in the device. Recently, it has been observed that metallic nanotubes can carry up to 25 μA of current at high bias. Our work indicates that the observed current saturation phenomena are not a contact-related issue, but rather due to electron-phonon scattering. Moreover, we demonstrate a tunable change in current carrying capacity, up to 40 μA, and functional form of the current-voltage (I − V) characteristic. These changes can be understood quantitatively within a model predicting a transition between stimulated and spontaneous phonon emission as a function of the nanotube Fermi energy. Finally, we present the first observation of current saturation in semiconducting nanotubes which are in qualitative agreement with the phonon emission model

Improving carbon nanotube nanodevices: Ambipolar field effect transistors and high -current interconnects

Early studies of electron transport in single-wall carbon nanotubes (SWNTs) have been hindered by large resistance of the nanotube-contact interface and weak electrostatic coupling to the gate electrode. Several groups have shown that the contact resistance can be reduced to kΩ range by growing nanotubes directly on the substrate using chemical vapor deposition (CVD). In our work we implement this growth technique by fabricating electrodes from cobalt, which creates perfectly transparent nanotube-electrode contacts, [special characters omitted] = 0.98. In addition, we use high temperature anneal in hydrogen atmosphere to reduce defect density in the dielectric layer and enhance gate effectiveness. At low temperatures we reduce the amount of gate voltage needed to add a single electron to 0.8 μm long nanotube by an order of magnitude to 15 mV. Using these improvements, we demonstrate ambipolar transport in nanotube-based field effect transistor (TubeFET), and use it to develop a novel type of memory device for data storage. In a metallic nanotube, we show that gate voltage can be used to tune the reflection probability of defect-induced scattering centers. Furthermore, total scattering probability increases with device length, suggesting weak scattering from molecular adsorbates. Studies of resistance in metallic nanotubes reveal both metallic and insulating temperature behaviors, depending on the total reflection probability in the device. Recently, it has been observed that metallic nanotubes can carry up to 25 μA of current at high bias. Our work indicates that the observed current saturation phenomena are not a contact-related issue, but rather due to electron-phonon scattering. Moreover, we demonstrate a tunable change in current carrying capacity, up to 40 μA, and functional form of the current-voltage (I − V) characteristic. These changes can be understood quantitatively within a model predicting a transition between stimulated and spontaneous phonon emission as a function of the nanotube Fermi energy. Finally, we present the first observation of current saturation in semiconducting nanotubes which are in qualitative agreement with the phonon emission model

THE SURFACE CHARACTERIZATION OF THE ANODIZED ULTRAFINE-GRAINED Ti-13Nb-13Zr ALLOY

Titanium alloys are metal materials widely used in medicine owing to their suitable characteristics such as low density, good corrosion resistance and biocompatibillity. High biocompatibility of the titanium alloy results from the creation of a spontaneous oxide layer with good adhesion and homogeneous morphology. In order to improve characteristics of the metallic materials for application in medicine, electrochemical methods that enable surface nanostructured modification are extensively used, and one of these methods is electrochemical anodization which makes it possible to obtain a nanostructured oxide layer composed of nanotubes on the surface of the metal material. The tested material was ultrafine-grained Ti-13Nb-13Zr (UFG TNZ) alloy obtained by the severe plastic deformation (SPD) processing using the high pressure torsion (HPT) process. Nanostructured oxide layer on the titanium alloy was formed by electrochemical anodization during the time period from 30 to 120 minutes. Characterization of the surface morphology obtained during different times of electrochemical anodization was done using scanning electron microscopy (SEM), while the topography and surface roughness of the titanium alloy before and after electrochemical anodization was determined using atomic force microscopy (AFM). Scratch test was used to determine the cross profile of the surface topography and critical load during scratching. Electrochemical anodization led to the formation of a nanostructured oxide layer on the surface of the titanium alloy. The obtained results indicated strong influence of the electrochemical anodization time on the oxide layer morphology - with its increase the diameter of the nanotubes increases too, while the wall thickness of nanotubes decreases. Also, electrochemical anodization led to an increase in the surface roughness

Flow characterization of various singularities in a real-scale ventilation network with rectangular ducts

International audienceFlow characterization in ventilation ducts is important for adequate modeling of contamination transfer. Turbulent flow through straight tubes with circular cross-section has been widely studied, but HVAC networks are quite unlike such ideal cases. Industrial ducts are of large scale, their sections can be rectangular, and they include many singularities (bends, T-junctions, reducers). The objective of this paper is to study the effect of such singularities on the flow in an industrial-scale rectangular ventilation network including over ten vertical and horizontal bends, one T-junction, a ventilation damper, and one section reducer, by performing experimental measurements and numerical simulations.Regarding bend flow, simulations of mean velocity profiles downstream of horizontal and vertical bends are validated on the experimental data. The analysis of the T-junction flow shows that this flow is a mix of bend and straight duct flows and probably depends on the flow distribution in the two inlet branches, as well as on the curvature radius of the T-junction. It is also observed experimentally that a deflector inserted inside a bend strongly impacts the velocity profiles up to 8Dh downstream. Experiments conducted on the impact of leakage in a closed ventilation damper show that this leakage flow cannot be ignored in the simulations. Measurements of the flow downstream of an open ventilation damper show significant variations in concentration homogeneity.These tests form an extensive database for flow measurements at industrial scale, useful for CFD validation, a necessary step before simulating gaseous and particulate flow in ventilation ducts

Influence of Multiple Anti-VEGF Injections on Retinal Nerve Fiber Layer and Ganglion Cell-Inner Plexiform Layer Thickness in Patients with Exudative Age-Related Macular Degeneration

Backgrounds and Objectives: To analyze the influence of multiple anti-VEGF intravitreal injections for exudative age-related macular degeneration on the thickness of peripapillary retinal nerve fiber layer (RNFL) and macular ganglion cell-inner plexiform layer (GC + IPL) using spectral domain optical coherence tomography (SD-OCT). Materials and Methods: A prospective interventional study of consecutive patients treated with intravitreal bevacizumab (IVB) was performed. Average and sectorial values of RNFL and GC + IPL thickness were recorded using Cirrus SD-OCT at 0, 6, 12, and 24 months. Patients suffering from any ocular disease that could affect RNFL or GC + IPL thickness were excluded. Results: A total of 135 patients (70 women and 65 men, aged 65 ± 15 years) were included. The average number of injections per patient was 12.4 ± 2.4. Average RNFL and GC + IPL thickness prior to the first injection (87.6 ± 12.2 and 47.2 ± 15.5 respectively), and after 24-month follow-up (86.2 ± 12.6 and 46.7 ± 11.9 respectively) did not differ significantly (p > 0.05). There was a significant decrease in GC2, GC5 segments, and minimum GC + IPL thickness. Conclusion: Repeated anti-VEGF treatment did not cause significant changes in the thickness of RNFL and GC + IPL layers over a period of 24 months. The detected decrease in GC2 and GC5 sectors, as well as in minimum GC + IPL thickness, could be a sign of ganglion cell damage induced by the treatment or could occur during the natural course of the disease