•Compact Tunable negative Metamaterial for enhancing 5G network performance.•Frequency-Tunable Tri-Hexagon and Tri-Square Split Ring Resonator for Bandwidth Optimization.•Empowering 5G with Double ...Negative (DNG) Properties.•Fabrication of the proposed metamaterial experimental result to verify the overall performance.
This paper introduces a compact tuneable metamaterial (MTM) unit cell featuring a tri-hexagon and tri-square split ring resonator (THTSSSR) structure designed for 5G communication applications. Metamaterials are employed to achieve unique electromagnetic properties not found in natural materials. The design process involves the arrangement of three square rings and three hexagon rings as metallic patches on a Rogers substrate (RT 5880), measuring 7 x 7 mm2 with a thickness of 1.575 mm. The proposed design exhibits double negative (DNG) properties, with resonances in the transmission coefficient (S21) at 3.493 GHz and a bandwidth of −10 dB covering frequencies between 3.057 and 3.711 GHz. Numerical simulations conducted using finite-integration techniques (FIT) in CST Microwave Studio validate the design's effectiveness, with confirmation through the Advanced Design System (ADS). The MTM unit cell demonstrates tuneable attributes, including negative permittivity ranging from 3.39 to 5 GHz and negative permeability from 3.39 to 3.86 GHz. These findings highlight the compactness and tunability of the proposed design, making it promising for 5G communication applications.
This study analyzed the social process of identity formation in left-handed athletes. It used convenience and snowball sampling methods for in-depth interviews and recruited participants through a ...network of left-handed athletes who nurtured an interest in academic research and expressed willingness to participate. The results of this study are as follows. First, left-handed athletes experienced social discrimination and disadvantage due to prejudice against left-handed people before starting sports. Through the social discrimination and disadvantage, they unknowingly developed a negative view of left-handers and experienced a socially isolated phenomenon. Second, left-handed players discovered a new self as they start exercising. They experienced the advantage of being a left-handed player in a sporting event and were recognized as useful players on the team. Third, left-handed athletes who demonstrate excellent skills in athletics received a lot of attention from peers and parents even after they enter society, served as role models, and were recognized for their abilities. Through this process, left-handed athletes can lead a dignified life as members of society with confidence as left-handed athletes. This study is significant in that it analyzes the socialization process of identity formation experienced by left-handed athletes as they start exercising.
Double-negative performance has played a significant role in electronic applications owing to its both permeability and permittivity negative values. Microwave absorption material has a substantial ...role in electromagnetic shielding, radar absorption, stealth applications, etc. Herein, a novel double-negative metacomposite, SrFe12O19/rGO, was designed by a simple one-pot hydrothermal method, and the microwave absorption properties of the material were studied in the microwave region from 2 to 18 GHz using VNA analysis. The structural and morphological studies were analysed using XRD, FT-IR, and SEM instrumentation techniques and the magnetic property of the material was studied using VSM analysis. Both studies confirmed the hard magnetic nature of the material. The particle sizes of SrFe12O19 and SrFe12O19/rGO measured from XRD are 55.60 nm and 41.55 nm, respectively. Hexagonal plate-like morphology were observed from FESEM images. The coercivity of SrFe12O19/rGO increased, and the magnetocrystalline anisotropy was changed due to the decrease in particle size. The magnetic saturation value decreases due to the presence of non-magnetic rGO. The resultant SrFe12O19/rGO metacomposite shows negative permittivity and permeability values. The minimum reflection loss values observed for pure and rGO-decorated strontium ferrites are −28.49 dB at 7.76 GHz and −23.78 at 11.04 GHz, respectively. In addition to experimental results, simulation studies were also performed to study the reflection loss with matching thickness using a quarter wavelength mechanism. The results show that this composite can be employed as a left-handed metamaterial that finds applications in absorption, antennas, sensors, wireless power transfer systems, etc. The left-handed metamaterial can shift the frequency region from a lower to a higher frequency region. The rGO decorated metacomposite is a promising material for microwave absorption at higher frequency regions.
This paper shows a technique to enhance the radiation gain and efficiency of metamaterial (MTM) inspired planar antenna using substrate integrated waveguide (SIW) technology for sub‐6 GHz wireless ...communication systems. The antenna consists of MTM unit‐cells comprising series interdigital‐capacitor and short‐circuited spiral stub. The proposed antenna behaves like a leaky wave antenna. In the transmission mode the input signal propagating along the antenna structure and leaks energy. The performance of the antenna is shown to enhance by embedding a column of metallic vias between the MTM unit‐cells. This technique has no impact on the size of the antenna. The antenna was constructed on a standard FR4 dielectric substate. It had dimensions of 23.2×6.4×0.8 mm3 and had a wide operational frequency range 1.8 GHz from 3.0–4.8 GHz. After applying SIW the average gain and efficiency of the antenna were 5.8 dBi and 78%, respectively, which is an improvement of 2 dBi and 21% across 3–4.8 GHz.
In this paper, a ferrite-filled rectangular waveguide as a balanced composite right/left-handed (CRLH) transmission line is considered. Based on the surface current density of dominant mode, a ...centerline longitudinal slot on the broad wall of this ferrite-filled rectangular waveguide can be radiate to the free space as a leaky-wave antenna (LWA). This proposed LWA has the both capability of the fixed-bias frequency scanning and fixed-frequency bias scanning from negative to positive angles. However, the gain of the centerline slotted ferrite-filled rectangular waveguide antenna is not acceptable. By adding another slot and changing the position of slots on the broad wall, the gain is improved to more than 9 dB in frequency range of 6.59-6.69 GHz.
Background
Left‐handers make up 10%–12% of all surgeons. Surgical education and practice by nature has significant technical demands but there is a paucity of data on left‐handers and training in ...surgery. The surgical curriculum has no specific salutation or recognition of left‐handers and the contributions and challenges they represent.
Methods
The purpose of the study was to explore, describe and understand the lived experience of left‐handed surgeons in relation to surgical education and training in Australia. Semi‐structured interviews were used to gather in‐depth information relating to the participants' experiences, viewpoints, beliefs and motivations.
Results
The responses of the participants involved were categorized using the data analysis method described by Colaizzi. Seven themes were identified: left‐handed surgeons are universal adapters; left‐handed instruments are not necessary for left‐handed trainees; most left‐handed trainees have experienced discrimination or negativity due to their laterality; ambidexterity is considered an advantage; communicating one's laterality is important; a formal mentoring program is not necessary; and simulation can be a complementary tool for left‐ handed trainees. Being a left‐handed surgical trainee need not be a negative experience.
Conclusion
With appropriate support and teaching, left‐handed trainees can develop into excellent surgeons. The themes from this study can be used by trainees, trainers and Colleges of surgical training to build awareness and optimize the training of future left‐handed surgeons.
The discovery of a reversible transition in the helical sense of a double-helical DNA was initiated by the first synthesis in 1967 of the alternating sequence polyd(G-C). In 1968, exposure to high ...salt concentration led to a cooperative isomerization of the double helix manifested by an inversion in the CD spectrum in the 240-310 nm range and in an altered absorption spectrum. The tentative interpretation, reported in 1970 and then in detailed form in a 1972 publication by Pohl and Jovin, was that the conventional right-handed B-DNA structure (R) of polyd(G-C) transforms at high salt concentration into a novel, alternative left-handed (L) conformation. The historical course of this development and its aftermath, culminating in the first crystal structure of left-handed Z-DNA in 1979, is described in detail. The research conducted by Pohl and Jovin after 1979 is summarized, ending with an assessment of "unfinished business": condensed Z*-DNA; topoisomerase IIα (TOP2A) as an allosteric ZBP (Z-DNA-binding protein); B-Z transitions of phosphorothioate-modified DNAs; and parallel-stranded polyd(G-A), a double helix with high stability under physiological conditions and potentially also left-handed.
Carboxylated cellulose nanocrystals prepared by TEMPO-mediated oxidation exhibit a distinct ability to form nematic order, however, their ability to form chiral nematic films remains relatively ...unexplored. In this study, bleached cotton pulp hydrolyzed with hydrochloric acid and oxidized by TEMPO-mediated oxidation produce carboxylated cellulose nanocrystals with different aspect ratios 33.1, 32.8, 30.9, 29.0 and 28.9, and surface charge densities 0.16, 0.56, 1.00, 1.25, and 1.42 e·nm−2. By tuning the aspect ratio and surface charge density, the optimal carboxylated cellulose nanocrystals producing left-handed chiral nematic films by evaporation-induced self-assembly are obtained. The left-handed chiral nematic films enable selective reflection of left-handed circularly polarized light with the peak wavelength tunable from the visible to the near-infrared regime by modifying the characteristics of nanorods and suspensions. Such carboxylated cellulose nanocrystal films transform spontaneous luminescence to right-handed circularly polarized luminescence with the peak luminescence dissymmetry factor of −0.51.
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Programmable chiral biocatalysis represents a promising therapeutic strategy for its high stereospecific control over various biotransformations (e.g., chiral Aβ isomerization) of living entities yet ...is rarely explored. With an extraordinary resistance to nuclease digestion, the non‐natural left‐handed deoxyribozyme (l‐DNAzyme) therapy is constrained by inefficient delivery/release and insufficient cofactors supply. Herein, an efficient adenosine triphosphate (ATP)‐stimulated disassembly of l‐histidine (l‐His)‐integrated ZIF‐8 (l‐His‐ZIF‐8) is reported for sustaining the l‐DNAzyme‐amplified photodynamic therapy. This self‐sufficient l‐therapeutic platform can intelligently release the l‐DNAzyme probe and simultaneously supply l‐His DNAzyme cofactors via endogenous ATP. Then, the intrinsic microRNA‐21 catalyzes the generation of robust l‐DNAzyme via the catalytic hybridization reaction for activating the photosensitizer with multiplied guaranteed therapeutic operation. This l‐therapeutic strategy opens up great prospects for more precise diagnosis and customized gene silencing‐based therapy.
The adenosine triphosphate (ATP)‐stimulated disassembly of functional l‐His‐ZIF‐8 NPs is reported for sustaining the left‐handed deoxyribozyme (l‐DNAzyme)‐amplified photodynamic therapy via the intelligent release of l‐DNAzyme probes and the simultaneous supply of l‐histidine cofactors via endogenous ATP and microRNA.
