Post COVID-19 irritable bowel syndrome

Objectives: The long-term consequences of COVID-19 infection on the gastrointestinal tract remain unclear. Here, we aimed to evaluate the prevalence of gastrointestinal symptoms and post-COVID-19 disorders of gut-brain interaction after hospitalisation for SARS-CoV-2 infection. Design: GI-COVID-19 is a prospective, multicentre, controlled study. Patients with and without COVID-19 diagnosis were evaluated on hospital admission and after 1, 6 and 12 months post hospitalisation. Gastrointestinal symptoms, anxiety and depression were assessed using validated questionnaires. Results: The study included 2183 hospitalised patients. The primary analysis included a total of 883 patients (614 patients with COVID-19 and 269 controls) due to the exclusion of patients with pre-existing gastrointestinal symptoms and/or surgery. At enrolment, gastrointestinal symptoms were more frequent among patients with COVID-19 than in the control group (59.3% vs 39.7%, p<0.001). At the 12-month follow-up, constipation and hard stools were significantly more prevalent in controls than in patients with COVID-19 (16% vs 9.6%, p=0.019 and 17.7% vs 10.9%, p=0.011, respectively). Compared with controls, patients with COVID-19 reported higher rates of irritable bowel syndrome (IBS) according to Rome IV criteria: 0.5% versus 3.2%, p=0.045. Factors significantly associated with IBS diagnosis included history of allergies, chronic intake of proton pump inhibitors and presence of dyspnoea. At the 6-month follow-up, the rate of patients with COVID-19 fulfilling the criteria for depression was higher than among controls. Conclusion: Compared with controls, hospitalised patients with COVID-19 had fewer problems of constipation and hard stools at 12 months after acute infection. Patients with COVID-19 had significantly higher rates of IBS than controls. Trial registration number: NCT04691895

Ab initio calculation of the structural, elastic, electronic, and linear optical properties of ZrPtSi and TiPtSi ternary compounds

The structural, elastic, electronic, and optical properties of orthorhombic ZrPtSi and TiPtSi ternary compounds are investigated using the norm-conserving pseudopotentials within the generalized gradient approximation (GGA) in the frame of density functional theory. The calculated lattice param- eters have been in agreement with the available experimental data. The second-order elastic constants have been calculated, and the other related quantities such as the Young’s modulus, shear modulus, Poisson’s ratio, anisotropy factor, sound velocities, and Debye temperature have also been estimated. The electronic structure of ZrPtSi and TiPtSi compounds are calculated by using the first principles GW and GGA approximations. The real and imaginary parts of the dielectric function and the optical constants such as the optical dielectric constant and the effective number of electrons per unit cell are also presented

An ultra-wide band low-SAR flexible metasurface-enabled antenna for WBAN applications

In this study, an ultra-wideband low-specific absorption rate (SAR) flexible metasurface-enabled wearable antenna is proposed for wireless body area network applications. The antenna and metamaterial (MM) structure were designed and analyzed using a commercial electromagnetic simulation software program which uses a finite integration technique solver. The antenna is designed and fabricated on a jeans textile substrate in the size of 58 x 80 x 1 mm(3). Moreover, MM reflector was designed on a felt textile substrate to reduce the SAR effect of the antenna and to increase the antenna performance (such as impedance matching, radiation pattern, and realized gain) parameters. Designed and fabricated antenna parameters and the SAR value results with and without MM are investigated. The simulated peak SAR values when the antenna with MM is placed on the body model are 0.86, 0.198, and 0.103 W/kg at frequencies of 4 GHz, 7 GHz, and 10 GHz, respectively, for 10 g of tissue. The simulated peak SAR value of the antenna with MM is also reduced by a percentage of 97, compared to the simulated peak SAR value of the antenna without MM. The peak SAR values of the antenna were less than the European safety limit of 2 W/kg for 10 g of tissue when the MM was used as an isolator. Furthermore, the simulated peak realized gain value of the antenna with the MM was increased by 98% (from 4.6 to 9.1 dB) compared to the simulated peak realized gain value of the antenna without MM. Simulation and measurement results showed that performance characteristics and peak SAR values of the proposed antenna were suitable and safe for wearable technologies

Stub Loaded Patch Antenna and a Novel Method for Miniaturization at Sub 6 GHz 5G and Wi-Fi Frequencies

This paper presents both a comprehensive analysis of a stub loaded rectangular patch antenna and a novel method to achieve more compact sizes for the antenna. It has been found that with certain stub dimensions the operating frequency shifts about 24%-27% to the lower ranges and it is possible to design the antenna with more compact sizes at these shifted bands. The model antennas are designed to operate at sub 6 GHz 5G bands and 5.8 GHz Wi-Fi band. It has been shown that the method can also be used for any frequency between 1.3 GHz and 8 GHz. Detailed parametric analyses have been performed for the best results. With these modifications, it is attained a remarkable size reduction from nearly 0.32 lambda(2) to 0.16 lambda(2) which means a decrease of 50% for each antenna with almost the same or better radiation characteristics. Moreover, to explain the method clearer a flow chart is given for the design procedure and to gain more confidence for our simulation results a prototype for 2.4 GHz is fabricated and measured. It has been proven that experimental measurements and simulation results are in good agreement

Multichromic Vanadium Pentoxide Thin Films Through Ultrasonic Spray Deposition

Vanadium pentoxide (V2O5) is a highly promising material for optoelectronic applications due to its wide optical band gap, significant thermal/chemical stability, and intriguing multichromic properties. Nonetheless, the production of uniform and crack-free V2O5 thin films over large areas via conventional deposition methods remain to be a challenge. In this work, we demonstrate deposition of microscopically uniform, large area (15 cm x 15 cm), nanocrystalline and multichromic V2O5 thin films onto fluorine-doped tin oxide (FTO) coated glass substrates via ultrasonic spray deposition (USD) method. Thin-film formation behavior, microstructural and optoelectronic properties of the deposited films were investigated as a function of post-deposition annealing temperature. Electrochromic performance of the fabricated films up to an area of 15 cm x 15 cm was monitored using cyclic voltammetry (CV), where 3 different coloration states of V2O5 were observed under different applied potentials. Electrochromic devices fabricated with the deposited V2O5 thin films were found to be stable up to 1000 cycles. Results presented herein provide a new roadmap for the large area deposition of V2O5 through USD method, which can be readily extended to a vast number of other functional metal oxide systems. (c) 2021 The Electrochemical Society ("ECS"). Published on behalf of ECS by IOP Publishing Limited