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In this paper, the resonance characteristics of aperture type frequency selective surface (FSS) is presented. A systematic investigation is carried out to design the compact FSS. The optimized structure consists of rectangular Archimedean spiral with inter-digital capacitance. Resonance characteristics is verified in both single-layer as well as the double-layer approach by embedding FSS on one side of the dielectric substrate. The performances of the dual-layer are observed by varying air-gap between two FSS layers. The structure offers satisfactory resonance (transmission and reflection) characteristics at optimum air-gap of 7 mm between two layers with the 3 dB cutoff region over a frequency range (3.66–4.66 GHz). Finally, an array of 31 × 31 FSS elements of two layers is fabricated for experimental characterization. A close agreement between simulated and measured results is observed. [ABSTRACT FROM AUTHOR]

The defected ground structure (DGS) technique enables miniaturization of the resonator which leads to the development of the compact near-field wireless power transfer (WPT) systems. In general, numerous challenges are inherent in the design of the DGS-based WPT systems and, hence, appropriate trade-offs for achieving optimal performance are required. Furthermore, the design advancements have led to the development of the DGS-based multi-band WPT systems to fulfill the needs of simultaneous data and power transfer. The innovations in the DGS-based WPT systems have also resulted in the definition of more commonly used figures-of-merit for the benchmarking of various performance metrics. The literature is replete with the design schemes to address one or more associated design challenges and successful WPT system realizations with enhanced performance. With this in mind, this paper touches upon the DGS-based WPTs developments and presents a concise report on the current state-of-the-art and future directions.

The potential advantages of simultaneous wireless information and power transfer (SWIPT) applications have necessitated innovations in the associated circuits and systems. This article, therefore, explores the concept of cascaded resonators, for the first time, in the design of a compact‐size defected ground structure (DGS)‐based tri‐band wireless power transfer (WPT) system to advance the SWIPT technology. The design is augmented with a systematic design procedure that is preceded by the development of a new double‐elliptic DGS‐based tri‐band resonator. Initially, the analysis of the proposed resonator is performed to identify the impact of defect size on the bandwidth. Subsequently, the resonators are cascaded to achieve a tri‐band functionality and then utilized in the design of WPT. The designed WPT operates at 0.3, 0.5, and 0.9 GHz, and takes a compact size of 39 × 13 mm2. The measurement of the realized WPT with the transmitter and receiver, separated by the distance of 10 mm, provides an efficiency of around 60% at all three bands with the figure of merit values of about 0.5. Furthermore, the proposed design achieves a bandwidth of more than 3 MHz bandwidth at the frequencies corresponding to communication standards. [ABSTRACT FROM AUTHOR]

Background: The irrational use of antibiotics has led to the emergence of multi drug resistant pathogens. The phenomenon of MIC creeps occurs when organisms start showing raised MIC but within susceptible range giving an indication of the prevalence of rise in resistant pathogens in an area., Methods: A cross sectional study in a large tertiary care hospital in North India to observe the susceptibility pattern among uropathogens and the possibility of MIC creeps. The Antimicrobial Susceptibility Testing (AST) and Minimum Inhibitory Concentration (MIC) were conducted by Vitek Compact 2. The identification of Extended Spectrum Beta Lactamase (ESBL) producers and Carbapenem Resistant Enterobacteriaceae (CRE) among Escherichia coli were noted. The MIC 50 and MIC 90 for Nitrofurantoin, the most widely used antibiotic for lower UTI, was calculated to investigate the phenomenon of MIC creep., Results: In our study, a total of 2522 urine samples were analyzed: 1538 (61%) were positive with the commonest isolate being E. coli (n=736, 47.8%) followed by Klebsiella spp. (n=178, 11%). Less than 10% of resistance was observed for Fosfomycin, Amikacin, Nitrofurantoin, Imipenem, Meropenem and Colistin. ESBL producers and CRE E. coli were 528 (72% of 736) and 79 (11% of 736) respectively. Overall, 119/736 samples had an MIC ≥128. Amongst the ESBL producers, 96/528 had MIC ≥128 and amongst the CRE, 13/79 had MIC ≥128., Discussion: E. coli can be used to reflect the trends in development of resistance. In the current study, it was observed that E. coli showed a reduced susceptibility for Nitrofurantoin indicated by a creeping increase in MIC albeit within normal range., Conclusions: Trends in rising MIC should alert prescribers to use drugs such as Nitrofurantoin judiciously. Antimicrobial stewardship practices should be strongly implemented in hospitals to curb rising resistance and obtain better treatment outcomes for patients with infectious diseases.

Ludwig's angina is a rapidly spreading, potentially fatal infection of deep fascial spaces of the neck leading to airway oedema and death. This, in recent times when associated with COVID-19 infection, possess treatment challenges making the patient susceptible to opportunistic infections with reduced healing potential. Owing to the multifactorial aetiology in our case and addressing them at the earliest, it is important to achieve favourable outcomes. The space infection that seeded with untreated trivial dental caries progressed to necrotising fasciitis of neck with mycobacterial growth on cartridge-based nucleic acid amplification test for tuberculosis testing. The presence of Mycobacterium organisms should be speculated in patients with pulmonary signs of tuberculosis (TB) because a suppurative TB lymphadenitis of neck could also have the same presentation. The decisive moment in successful outcome was identification of mycobacteria in COVID-19 infected patient, thereby allowing to initiate the antitubercular therapy along with surgical debridement. Thus, medical management of patient with cohabiting infections is difficult task and needs appropriate addressal., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

In this paper, viability of low-cost off-the-shelf Piezoelectric ceramic disc elements is explored for an insole-based gait monitoring system, `PI-Sole' (Piezo In-Sole). Piezoelectric elements can sense dynamic changes in pressure in a closed-loop environment with good sensitivity and a wide measurement range. In this paper, method to enable these elements to continuously sense plantar pressure while walking is proposed, making them a very cost-efficient alternative to the widely used Force Sensing Resistors (FSR) and pressure plates for monitoring human gait. However, piezoelectric elements show hysteresis in their force response, inducing a drift in calculated pressure which increases with time. A novel and effective method to perform detrending of the signal is also presented utilizing stride contexts from a 6-DoF Inertial Measurement Unit (IMU) and the same is utilized to perform zero-correction in the pressure data. 3-D trajectories of strides are calculated using the IMU, and parameters like stride length, stride height etc. are further derived. In order to test the validity of our proposed methods, important kinetic parameters like Vertical Ground Reaction Force (VGRF) and Center of Pressure (CoP) are calculated using PI-Sole and compared to the ones calculated using FSR's in multiple prior works. Applicability of PI-Sole is demonstrated further by depicting and analysing characteristic differences between a heel-strike toe-off stance type, and a flat-strike stance type, the latter being one of the primary symptoms in many cases of pathological gait, including Parkinsonian gait. Important artefacts from foot's height profile while walking are analysed for both stance types in context of standard gait events. We report a mean error of 2.8cm in stride length calculation, and a mean accuracy of 94.5% in calculating swing/stance duration of gait cycles.