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With the emerging use of wireless applications, the radio frequency community continues to need to design miniature, lightweight, and inexpensive antennas that can easily be integrated into small-scale communication systems. According to today's global wireless applications, Circularly Polarized Microstrip Antennas (CPMAs) offer more flexibility for handheld and portable wireless devices due to their insensitivity to the orientation of the device and multipath effects. These antennas are best suited for wireless communications such as WLAN, RFID and GNSS applications. The objective of this work is to design a miniature microstrip antenna with circular polarization, intended for wireless applications such as positioning systems by GNSS satellites. The design will be done in two stages. First, we will design a patch antenna operating at the 1.575 GHz frequency using the technique of asymmetric circular slots to obtain circular polarization. The second step consists in miniaturizing the dimensions of this antenna thanks to a network of square-shaped SRR resonators, inserted at the level of the ground plane of the structure. The result is an antenna of compact size and well suited to the intended application. Simulation results are discussed and compared in terms of reflection coefficient, bandwidths, radiation patterns and axial ratio.

In a context of increasing communication standards, the need for the miniaturization of antennas facilitating their integration is increasing more and more. This paper has been devoted to the use of lefthand materials (LHM) for reducing the size of circular microstrip antenna as well as improved bandwidth. The antenna is designed to serve WLAN applications at operating frequency of 5 GHz. The design process begins by a simple circular patch antenna feed by a coaxial cable and designed on aFR4 dielectric substrate with total ground plane in its backward side. The iniaturization technique consists of placing the complementary split ring resonator cells on the ground plane. A size reduction of 35% is reached without losing the performance of the initial antenna. The design, and the simulation of the poposed antenna were completed using the CST Microwave Studio simulator. The numerical result show that satisfactory results have been obtained in terms of miniaturization and adaptation as well as improvement in the bandwidth at resonant frequency compared to the conventional antenna.

The objective of this work is the design and simulation of an antenna based on metamaterials in order to miniaturize the initial dimensions of the planar antennas. Metamaterials are on the rise in recent years. The new properties make it possible to consider the production of new electronic components with new functionalities. Metamaterials are artificial materials designed for different telecommunications applications in order to improve the performance of antennas in terms of efficiency, compactness and miniaturization of structures. The use of these materials offers advantages such as reduction in weight and bulk, which is beneficial for their integration into 5G and WIMAX telecommunications and telephony systems [1]. As part of this work, a set of simulations allowed us an understanding of the different characteristics of metamaterials engraved on planar antennas that resound in the 2.6 GHz frequency. This work is based on the performance monitoring of rectangular patch antennas using these materials. The purpose of this work is to achieve studying parametric to develop a miniature patch antenna optimally Original likely to meet the needs of systems without current son, conc u by the software simulation 3D CST Studio Suite and Matlab computer.

We report herein a case of bacteremic ascitic fluid infection in a liver transplant patient caused by a strain of Yersinia pseudotuberculosis serogroup I that lost the yersiniabactin core. The patient's outcome was favorable after a combined therapy with a third-generation cephalosporin and gentamicin. [ABSTRACT FROM AUTHOR]

Introduction: Endoscopic ultrasound-guided gastroenterostomy (EUS-GE) is increasingly used in the setting of malignant gastric outlet obstruction (GOO). However, little is known about the role of primary EUS-GE. The aim of the present study is to compare the outcomes of EUS-GE by using the freehand technique as a first- and second-line approach after enteral stenting (ES)., Methods: This is an observational single-center study using a prospectively collected database. All consecutive patients who underwent an EUS-GE using the freehand technique due to malignant GOO were included. Patients with previous gastric surgery, a wire-guided EUS-GE technique, or those presenting without GOO were excluded. The primary outcome was the clinical success, defined as a solid oral intake at 1 week after the procedure (GOO Score, GOOSS ≥ 2). The secondary outcomes were technical success and adverse event (AE) rates. The impact on nutritional parameters was also assessed., Results: Forty-five patients underwent an EUS-GE for all indications. Finally, 28 patients (mean age: 63 ± 17.2 years, 57.1% male) with ( n = 13, 46.4%) and without ( n = 15, 53.6%) a previous ES were included. The technical success was achieved in 25 cases (89.3%), with no differences between the two groups (92.3% vs. 86.7%, p = 1). The median limb diameter and procedure time were 27 mm (range:15-48) and 37 min. Overall, clinical success was achieved in 22 cases (88%), with three failures due to AEs ( n = 2) or peritoneal carcinomatosis ( n = 1). The diet progression was quicker in patients with a previous ES (GOOSS at 48 h, 2 vs. 1, p = 0.023), but the GOOSS at 1 week ( p = 0.299), albumin gain ( p = 0.366), and BMI gain (0.257) were comparable in the two groups. The AE rate was 7.1%., Conclusions: EUS-GE achieves a high technical and clinical success in patients with GOO regardless of the presence of a previous ES. Patients with previous ES may have a quicker progression of their diet, but the GOOSS and nutritional status in the long term at 1 week or 1 month are comparable. Primary EUS-GE might require fewer procedures and less discontinuation of chemotherapy to achieve a comparable result.

Introduction: biodegradable stents of various designs are reportedly used in pancreato-biliary conditions with promising results. Their major advantage is the avoidance of repeat endoscopic procedure for stent removal, thereby reducing overall costs and endoscopic retrograde cholangiopancreatography (ERCP) associated adverse events. The aim of the study was to evaluate the feasibility and safety of a new biodegradable stent in patients with pancreato-biliary diseases., Methods: a prospective multicenter pilot study was performed. All consecutive patients ≥ 18 years old who underwent biliary or pancreatic stenting using the new biodegradable Archimedes stent were included in the study. There were three biodegradation profiles. Technical and clinical success and feasibility and safety were assessed during a pre-established follow-up schedule., Results: fifty-three patients (mean age: 48.54 ± 19.29, 66 % male) with biliary (n = 29, 54.7 %) or pancreatic (n = 24, 45.3 %) indications were included. The distribution of stents used according to degradation properties were as follows: fast (n = 11, 20.8 %), medium (n = 16, 30.2 %) and slow (n = 26, 49.1 %). The technical and clinical success were 100 % and 77.8 %, respectively. Thirty-five patients were followed for a median of 26 weeks (range: 4-56, 66 %). There were nine procedure-related adverse events (17 %), all mild, including one uneventful stent-related event (external migration)., Conclusion: the biodegradable Archimedes stent placement is feasible and safe in pancreato-biliary diseases.

Background and Aims: The role of small bowel neoplasia (SBN) screening in asymptomatic patients with Lynch syndrome (LS) is uncertain. The aim of our study was to assess the effectiveness of screening by capsule endoscopy (CE) in these patients., Methods: This study was an observational, analytical, and retrospective single-center study within the PRED-IdF network. All consecutive asymptomatic patients older than 35 years-old with confirmed LS and no personal history of SBN who started the screening from 2010-2015 were included. The baseline screening and 24 months follow-up were performed by CE. The CE diagnostic yield (positive tumor or polyp) and accuracy, using the follow-up as gold standard, were evaluated., Results: A total of 150 patients underwent the SBN screening program and 135 (52.7 ± 11.2 years-old, 37.8% male) met the inclusion criteria. The baseline CE diagnostic yield was 4.4% (3 polyps, 3 tumors) and the proximal small bowel was the most common location ( n  = 4, 66.7%). In total, 87 patients underwent follow-up and the diagnostic yield was 4.6%.Four patients were considered positive at follow-up (2 adenomas, 2 adenocarcinomas). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CE were 60%, 100%, 100%, 96.9%, and 97%, respectively., Conclusions: CE is an accurate procedure for baseline screening of SBN in LS patients and may be efficient for follow-up procedures. However, the optimal starting age of screening and intervals of follow-up must be clarified., Competing Interests: Conflict of interest statement: The authors declare that there is no conflict of interest., (© The Author(s), 2020.)

Background and study aims  Over-the-scope clip (OTSC) has been recently used in management of gastrointestinal perforations, but data on it are still limited. The aim of this study was to compare management of iatrogenic perforations before and after the OTSC was available in our endoscopy unit. Patients and methods  We conducted a monocentric retrospective study from June 2007 to June 2015. All iatrogenic gastrointestinal perforations detected during endoscopy were included. Two time periods were compared in terms of surgery and mortality rates: before use of OTSC (June 2007 to June 2011) and after OTSC became available (June 2011 to June 2015). Results  During the first period, 24 perforations were recorded. Fifteen (62.5 %) were managed with surgery. The mortality rate was 8 %. During the second period, 16 perforations occurred. In 11 patients (68.7 %), an OTSC was used to close the perforation, with complete sealing of the perforation in 100 % of cases. However, 2 patients with sigmoid perforation had to undergo surgery due to right ureteral obstruction by the clip in 1 case and to presence of a localized peritonitis in the other. The surgery rate during this period was 12.5 % (2 /16), with a statistically significant difference compared to the first period ( P  = 0.002). There was no mortality in the second period versus 8 % in the first one ( P  = 0.23). Conclusions  OTSC is effective for endoluminal closure of iatrogenic perforations and results in a significant decrease in surgery rate.

We present a new examination of the EPR redox titration data for the tetraheme cytochrome c3 from Desulfovibrio vulgaris Miyazaki. Our analysis includes the contribution of the interaction potentials between the four redox sites and is based on the model previously developed for the study of cytochrome c3 from Desulfovibrio desulfuricans Norway. We observed, as for D. desulfuricans Norway cytochrome c3, that the conformation of the heme with the lowest redox potential, heme 4, is sensitive to the redox state of the heme with the highest potential, heme 1. However in D. vulgaris Miyazaki cytochrome c3 spectral simulations show that heme 4 is present in two conformational states which interconvert partially when heme 1 is reduced. The sets of redox parameters which satisfy the fitting procedure of the titration curves are in the following domain: -250 mV less than or equal to e41 less than or equal to -220 mV, -325 mV less than or equal to e2 less than or equal to -320 mV, -335 mV less than or equal to e3 less than or equal to -330 mV, -360 mV less than or equal to e4 less than or equal to -355 mV, -5 mV less than or equal to I12 less than or equal to 20 mV, -10 mV less than or equal to I13 less than or equal to 5 mV, -15 mV less than or equal to I23 less than or equal to -5 mV, -15 mV less than or equal to I24 less than or equal to -10 mV, -25 mV, less than or equal to I34 less than or equal to -15 mV. As in D. desulfuricans Norway cytochrome c3 the interactions are moderate. Simple electrostatic considerations suggest that these moderate values could be related to the large accessibility of the hemes to the solvent. Our work does not confirm the existence of a cooperative interaction between heme 2 and heme 3 which has been proposed on the basis of electrochemical measurements.

In cytochromes c3 which contain four hemes per molecule, the redox properties of each heme may depend upon the redox state of the others. This effect can be described in terms of interaction redox potentials between the hemes and must be taken into account in the characterization of the redox properties of the molecule. We present here a method of measurement of these interactions based on the EPR study of the redox equilibria of the protein. The microscopic and macroscopic midpoint potentials and the interaction potentials are deduced from the analysis of the redox titration curves of the intensity and the amplitude of the EPR spectrum. This analysis includes a precise simulation of the spectrum of the protein in the oxidized state in order to determine the relative contribution of each heme to the spectral amplitude. Using our method on cytochrome c3 from D. desulfuricans Norway, we found evidence for the existence of weak interaction potentials between the hemes. The three interaction potentials which have been measured are characterized by absolute values lower than 20 mV in contrast with the values larger than 40-50 mV which have been reported for cytochrome c3 from D. gigas. Simulations of the spectra of samples poised at different potentials indicate a structural modification of the heme with the most negative potential during the first step of reduction. The correspondence between the redox sites as characterized by the EPR potentiometric titration and the hemes in the tridimensional structure is discussed.