Network-Independent and User-Controlled RIS: An Experimental Perspective

The march towards 6G is accelerating and future wireless network architectures require enhanced performance along with significant coverage especially, to combat impairments on account of the wireless channel. Reconfigurable intelligent surface (RIS) technology is a promising solution, that has recently been considered as a research topic in standards, to help manipulate the channel in favor of users needs. Generally, in experimental RIS systems, the RIS is either connected to the transmitter (Tx) or receiver (Rx) through a physical backhaul link and it is controlled by the network and requires significant computation at the RIS for codebook (CB) designs. In this paper, we propose a practical user-controlled RIS system that is isolated from the network to enhance communication performance and provide coverage to the user based on its location and preference. Furthermore, a low-complexity algorithm is proposed to aid in CB selection for the user, which is performed through the wireless cloud to enable a passive and energy efficient RIS. Extensive experimental test-bed measurements demonstrate the enhanced performance of the proposed system while both results match and validate each other.Comment: Conference, 6 pages, 5 figures, 1 algorith

Mixed Bacteriological Isolation Percentages from the Uterus of Cows Slaughtered due to Infertility

Background: Intrauterine mixed infections are an important problem in cattle breeding. In this study, we aimed to determine the mixed bacteriological isolation rates from the uterus of cows with clinical metritis and to reveal the relationships between the bacteria that isolated together.Methods: For this purpose, sterile swabs were taken from 490 uterus obtained from cattle slaughtered due to infertility in three slaughterhouses and used them to perform microbiological tests. After evaluating the data, it was determined that the bacterial isolation rate from uterus with clinical metritis was 76.14% (n = 268).Results: The rates for 1, 2, 3, 4, and 5 bacteria isolated from the uterus with clinical metritis were 48.13%, 33.96%, 15.30%, 2.24%, and 0.37%, respectively. The isolation rates for Trueperella pyogenes, Fusobacterium necrophorum, and Escherichia coli alone from the uterus with clinical metritis were 27.08%, 28.00%, and 16.51%, respectively. In uterus with clinical metritis, Staphylococcus aureus (16.67%) was the most commonly isolated bacteria with T. pyogenes, Clostridium spp. (16%) co-isolated with F. necrophorum, and coagulase-negative staphylococci (16.51%) and Bacillus spp. (16.51%) were detected with E. coli.Conclusion: As a result, it was concluded that when evaluating the microbiological results for cows with clinical metritis, mixed infections should be taken into more consideration, and the characteristics of the bacteria that isolate together should be considered during the treatment of mixed infections.Keywords: Cattle; Uterine; Isolation; infertility     

Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey

Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10 years; 78.2% included were male with a median age of 37 years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020

Over-the-Air Equalization with Reconfigurable Intelligent Surfaces

Reconfigurable intelligent surface (RIS)-empowered communications is on the rise and is a promising technology envisioned to aid in 6G and beyond wireless communication networks. RISs can manipulate impinging waves through their electromagnetic elements enabling some sort of control over the wireless channel. In this paper, the potential of RIS technology is explored to perform a sort of virtual equalization over-the-air for frequency-selective channels whereas, equalization is generally conducted at either the transmitter or receiver in conventional communication systems. Specifically, with the aid of an RIS, the frequency-selective channel from the transmitter to the RIS is transformed to a frequency-flat channel through elimination of inter-symbol interference (ISI) components at the receiver. ISI is eliminated by adjusting the phases of impinging signals particularly to maximize the incoming signal of the strongest tap. First, a general end-to-end system model is provided and a continuous to discrete-time signal model is presented. Subsequently, a probabilistic analysis for the elimination of ISI terms is conducted and reinforced with computer simulations. Furthermore, a theoretical error probability analysis is performed along with computer simulations. It is analyzed and demonstrated that conventional RIS phase alignment methods, can successfully eliminate ISI and the RIS-aided communication channel can be converted from frequency-selective to frequency-flat

Relationship between increased mean platelet volume and glycosylated hemoglobin (HbA1c) in type 2 diabetes mellitus

Purpose: The purpose of the study was to research relationship between mean platelet volume elevation and glycosylated hemoglobin A1c (HbA1c) in Type 2 diabetes mellitus (DM). Material and Methods: The study carried out in 70 patients with type 2 DM and 50 non-diabetic subjects. Diabetic patients were divided into two groups according to their HbA1c levels: DM group1 consisted of patients with HbA1c levels <7% and DM group 2 consisted of patients with HbA1c levels and #8805;7%. Results: The mean HbA1c levels were as 5.5+/-0.8, 6.7+/-0.2 and 9.7+/-1.9 in the non-diabetic, DM Group 1 and DM Group 2, respectively. MPV was significantly higher in DM Group2 as compared to both non-diabetics and DM Group 1. MPV had a high positive Correlation with HbA1c. MPV was significantly higher in DM Group 2 as compared to both non-diabetics and DM Group 1. MPV had a high positive correlation with HbA1c. It is found that MPV was increased in type 2 DM. Conclusion: This study showed that in diabetes mellitus, MPV is increased and it is indicative of worsening glycemic control. The increased platelet size may be one of the factors in the increased risk of atherosclerosis associated with DM and associated micro and macro vascular complications. [Cukurova Med J 2016; 41(1.000): 13-16

Steady-state thermal-electric analysis of a pi-shaped 8-pair thermoelectric generator

In this study, steady-state thermal-electric analysis of a pi-shaped 8-pair TEG was performed by finite element method using thermal-electric module in Ansys Workbench for high temperature applications. TE powders of Ca2.7Ag0.3Co4O9 and Zn0.94Al0.04In0.02O were synthesized by sol-gel method followed by cold pressing (CP) to obtain bulk samples. High temperature thermoelectric properties of the bulk samples were used for p- and n-type legs, respectively. In the model, a Delta T temperature difference of 400 degrees C was applied to obtain a high temperature power output. As a result of the thermal-electric analysis, temperature distribution and total current density along the TEG were evaluated. (C) 2019 Elsevier Ltd. All rights reserved

High-Temperature Thermoelectric Properties of Sol-Gel Processed Ca2.5Ag0.3RE0.2Co4O9 (RE: Y and Rare-Earths) Materials

Herein, dually doped Ca2.5Ag0.3RE0.2Co4O9 (RE: La, Pr, Nd, Sm, Gd, Dy, Er, Yb, Eu, Tb, Ho, Lu, Ce, and Y) samples are synthesized by sol-gel technique and consolidated by cold pressing under high pressure to systematically scrutinize the influences of Y and rare-earth dually doping with Ag on transport properties of Ca3Co4O9 for high-temperature thermoelectric (TE) applications. Characterization results reveal that targeted phase is successfully produced, and doping of the compositions is provided. Doping of Y and rare-earth elements together with Ag into the Ca2+ site is effective in increasing the Seebeck coefficient and decreasing the electrical resistivity of the samples, thanks to the reduction in carrier concentration. Thermal conductivity of the samples is reduced related to the lower relative densities and alloy scattering originated from dually doping. Among the samples, Ca2.5Ag0.3Ho0.2Co4O9 and Ca2.5Ag0.3Eu0.2Co4O9 exhibit the highest power factor (PF) values of 0.65 and 0.62 mW m(-1) K-2 at 800 degrees C, respectively. These results are quite high for bulk oxide TE materials which can be assessed as potential oxide TE materials for high-temperature TE power generation

Effects of Electrical Properties on Determining Materials for Power Generation Enhancement in TEG Modules

This study aimed to increase the energy efficiency of thermoelectric generators designed by considering the electrical properties of p- and n-type semiconductor materials for reducing the costs associated with the experiments, errors, and long production processes. Accordingly, the estimation of the energy amount to be produced by the thermoelectric materials was achieved by different doping elements using three different parameters such as skin-depth, electrical conductivity and dielectric constant. Additionally, the findings were supported by experimental results. In contrast to the conventionally used black-box type approach and estimation methods, an inference was obtained on the actual values of the materials

High temperature thermopower of sol-gel processed Zn1-x-y Al (x) Me (y) O (Me: Ga, In)

In this study, dually doped samples of Zn1-x-y Al (x) Me (y) O (Me: Ga, In) were prepared by sol-gel process followed by hot isostatic pressing for high temperature thermoelectric applications. Material characterizations were performed with differential thermal analysis-thermogravimetry, Fourier transform infrared spectroscopy and X-ray diffraction on the target phases. Successful doping of the samples was confirmed by X-ray photoelectron spectroscopy and energy dispersive X-ray analysis. Thermopower values of the samples are found to be relatively high in analogy to semiconducting behavior in which negative values indicate electrons are the dominant charge carriers (n-type). Substitution of Zn2+ by Ga3+ and In3+ for Zn1-x-y Al (x) Me (y) O (Me: Ga, In) increases electron concentration in the samples and thereby decreases the thermopower values compared to Zn0.98Al0.02O. Considering the absolute values, In doped samples have higher thermopower (alpha (max) = -162 A mu V/K at 585 A degrees C for Zn0.96Al0.02In0.02O) compared to the Ga doped sample. Al and In dually doped Zn0.96Al0.02In0.02O could be considered as a promising n-type thermoelectric material for high temperature applications