bluuebunny/crossref_metadata_2025_split huggingface dataset:
Shared-aperture antennas based on mode modulation of a patch antenna and spoof surface plasmon polaritons
Authors: Qu Bingyue , Yan Sen , Zhang Anxue , Pang Yongqiang , Xu Zhuo 
Published: October 2021

Abstract
Light-weight shared-aperture antennas require the integration of multiple functions in separate frequency bands within the same physical aperture, having great potential use in remote sensing, radiometers, telemetry and communication, etc. In this letter, a method for designing light-weight shared-aperture antennas based on engineering of spoof surface plasmon polaritons (SSPPs) is presented. The proposed antenna consists of a feeding patch and a SSPP structure. Even and odd modes can be excited in different bands to realize different radiation performances. The simulated and measured results both corroborate that the presented shared-aperture antenna can achieveomnidirectional radiation at around 3.1 GHz and end-fire radiation at around 10.65 GHz, with peak gains about 1.90 dB and 6.24 dB, respectively. Without using several radiators and complex feeding networks, the antenna can work in two bands with different radiation patterns. This work provides an effective alternative design for shared-aperture antennas in light-weight and multi-functional wireless communication systems.
Dynamic phase transition in classical Ising models
Authors: Yüksel Yusuf , Vatansever Erol 
Published: October 2021

Abstract
When a ferromagnetic system is driven by an oscillating magnetic field, the system shows various intriguing magnetic properties. The two most common features are dynamic phase transition and dynamic hysteresis resulting from the competition between the period of the external field and the metastable lifetime of the system. In this article, we mainly review the similarities and dissimilarities between ferromagnetic systems in thermal equilibrium and those exposed to a driving time-dependent magnetic field. Extensive studies performed over two decades have shown that dynamic and thermodynamic phase transitions correspond to the same universality class and have similar phase diagrams, among other similarities. Remarkably, recent experimental studies have revealed that both fluctuations in dynamic order parameter and susceptibility can demonstrate anomalously sharp sidebands, which are known as metamagnetic anomalies, in the dynamically paramagnetic phase close to the critical point. This behavior is one of the most interesting behaviors observed in the magnetic systems driven by a time-dependent field which does not have an analog in the corresponding equilibrium counterparts. We discuss the general picture regarding the effects of the applied field components on the metamagnetic anomalies. As a main conclusion, we remark that a comprehensive literature overview reveals that the similarities between conventional thermodynamic phase transitions and corresponding dynamic counterpart are only limited to the vicinity of critical period regime with zero bias field, and they should be treated very carefully in the presence of surfaces. Finally, some of the main questions waiting to be answered and potential future research directions are underlined.
Ag/GO/TiO2 nanocomposites: the role of the interfacial charge transfer for application in photocatalysis
Authors: de Almeida Gabriella Correia , Della Santina Mohallem Nelcy , Viana Marcelo Machado 
Published: October 2021

Abstract
TiO2 semiconductor nanoparticles (NPs) in the anatase phase have presented limitations of application in photocatalysis, mainly due to the fast recombination of photoexcited electrons. The combination with other nanoparticles/nanostructures has been shown to be a promising solution for increasing photocatalytic efficiency. In this work, titanium dioxide (TiO2) nanoparticles in different crystalline phases were prepared through a rapid microwave-assisted synthesis and modified by silver nanoparticles (Ag) and graphene oxide (GO). The samples were characterized by x-ray diffraction, transmission electron microscopy, energy dispersive x-ray spectroscopy, infrared spectroscopy and gas adsorption. Crystalline anatase NPs were obtained in basic conditions (pH = 8) while in acidic conditions (pH = 1), single-crystalline rutile NPs were formed. Different previous drying methods: oven and freeze-drying used led to a differentiation in crystallographic phases obtained. Anatase TiO2 and anatase-rutile mixture NPs calcined at 400 °C showed properties as high specific surface area, crystallinity and reduced electron–hole recombination which contributed to an enhanced photocatalytic activity, when compared to the Degussa P25 photoactivity. The effect of silver nanoparticles and GO addition to TiO2 nanopowder was evaluated for photocatalysis activity. An improvement in the methylene blue and rhodamine B dyes photodegradation was observed for both anatase and rutile TiO2 nanocomposites. We noted that anatase TiO2 nanoparticles degraded 53% of rhodamine B, and when functionalized with GO, the photodegradation increased to 69%. Comparatively, the addition of silver nanoparticles to anatase TiO2 increased the dye degradation to 97% in 180 min. Hence, we revel that in the TiO2 nanocomposites, silver nanoparticles showed better interfacial charge transfer than GO, contributing more effectively to the dye photodegradation process.
Ink-jet printing and drop-casting deposition of 2H-phase SnSe2 and WSe2 nanoflake assemblies for thermoelectric applications
Authors: Patil B , Bernini C , Marré D , Pellegrino L , Pallecchi I 
Published: October 2021

Abstract
The development of simple, scalable, and cost-effective methods to prepare Van der Waals materials for thermoelectric applications is a timely research field, whose potential and possibilities are still largely unexplored. In this work, we present a systematic study of ink-jet printing and drop-casting deposition of 2H phase SnSe2 and WSe2 nanoflake assemblies, obtained by liquid phase exfoliation, and their characterization in terms of electronic and thermoelectric properties. The choice of optimal annealing temperature and time is crucial for preserving phase purity and stoichiometry and for removing dry residues of ink solvents at inter-flake boundaries, while maximizing the sintering of nanoflakes. An additional pressing is beneficial to improve nanoflake orientation and packing, thus enhancing electric conductivity. In nanoflake assemblies deposited by drop casting and pressed at 1 GPa, we obtained thermoelectric power factors at room temperature up to 2.2 × 10−4 mW m−1 K−2 for SnSe2 and up to 3.0 × 10−4 mW m−1 K−2 for WSe2.
The effect of an annealing process on atomic layer deposited TiO2 thin films
Authors: Kim Byunguk , Kang Taeseong , Lee Gucheol , Jeon Hyeongtag 
Published: October 2021

Abstract
In this paper, we study the property changes in TiO2 thin films related to annealing under various conditions. XPS analysis showed that the concentration of oxygen vacancies in TiO2 thin films was reduced by annealing. In the case of annealing in an O2 and air atmosphere, the oxygen vacancy concentration was reduced to the greatest extent as oxygen diffused into the TiO2 thin film and rearrangement of atoms occurred. XRD analysis showed that the anatase structure of annealed TiO2 thin films was clearly present compared to the as-deposited TiO2 thin film. I–V analysis showed that the lower the concentration of oxygen vacancy, the lower the leakage current (O2 annealed TiO2: 10−4 A cm−2) than as dep TiO2 thin film (∼10−1 A cm−2). The dielectric constant of annealed TiO2 thin films was 26–30 which was higher than the as-deposited TiO2 thin film (k ∼ 18) because the anatase structure became more apparent.
Disentangling ferroelectric domain wall geometries and pathways in dynamic piezoresponse force microscopy via unsupervised machine learning
Authors: Kalinin Sergei V , Steffes James J , Liu Yongtao , Huey Bryan D , Ziatdinov Maxim 
Published: October 2021

Abstract
Domain switching pathways in ferroelectric materials visualized by dynamic piezoresponse force microscopy (PFM) are explored via variational autoencoder, which simplifies the elements of the observed domain structure, crucially allowing for rotational invariance, thereby reducing the variability of local polarization distributions to a small number of latent variables. For small sampling window sizes the latent space is degenerate, and variability is observed only in the direction of a single latent variable that can be identified with the presence of domain wall. For larger window sizes, the latent space is 2D, and the disentangled latent variables can be generally interpreted as the degree of switching and complexity of domain structure. Applied to multiple consecutive PFM images acquired while monitoring domain switching, the polarization switching mechanism can thus be visualized in the latent space, providing insight into domain evolution mechanisms and their correlation with the microstructure.
Conversion of 2-dimensional GaSe to 2-dimensional β-Ga2O3 by thermal oxidation
Authors: Schmidt Constance , Rahaman Mahfujur , Zahn Dietrich R T 
Published: October 2021

Abstract
We demonstrate the conversion to quasi two-dimensional (2D) β-Ga2O3 by thermally oxidizing layered GaSe of different thicknesses (from bilayer to 100 nm). GaSe flakes were prepared by mechanical exfoliation onto Si with a 300 nm SiO2 layer, highly oriented pyrolytic graphite, and mica substrates. The flakes were then annealed in ambient atmosphere at different temperatures ranging from 600 °C to 1000 °C for 30 min. Raman spectroscopy confirmed the formation of β-Ga2O3 in the annealed samples by comparison with the Raman spectrum of a β-Ga2O3 reference crystal. Atomic force microscopy was employed to study the morphology and the thickness of the β-Ga2O3 flakes. In addition, we used energy dispersive x-ray spectroscopy together with scanning electron microscopy to investigate the evolution of the composition, especially Se residuals, and the sample topography with annealing temperature. β-Ga2O3 appears at temperatures above 600 °C and Se is completely evaporated at temperatures higher than 700 °C. The thicknesses of the resulting β-Ga2O3 flakes are half of that of the initial GaSe flake. Here we therefore present a straightforward way to prepare 2D β-Ga2O3 by annealing 2D GaSe.
Similarity properties in capacitive radio frequency plasmas with nonlinear collision processes
Authors: Yang Dong , Fu Yangyang , Zheng Bocong , Wang Huihui , Fan Qi Hua , Zou Xiaobing , Wang Xinxin , Verboncoeur John P 
Published: October 2021

Abstract
Similarity laws (SL) are essential for correlating the characteristics of plasmas at different dimensional scales, which have been validated for radio frequency (rf) discharges at low pressure but under limited conditions. In this work, we evaluate the effects of nonlinear collisions (e.g. stepwise ionization) on the similarity properties in capacitive rf discharges in argon across a wide range of pressure regimes via fully kinetic particle-in-cell simulations. The SL scalings of fundamental discharge parameters, e.g. the electron power absorption and electron energy probability function, are examined with and without nonlinear collisions, respectively. Without the nonlinear collisions, the similarity scalings are found to be rigorously valid. When the nonlinear collisions are considered, the similarity properties in rf discharges still exist approximately, which indicates that the violations caused by the nonlinear collisions are still minor in the studied cases. The reasons for the effectiveness of SL scalings with nonlinear collision processes are also discussed. The results from this study confirmed the validity of similarity transformations with more complex reaction kinetics, which may promote the applicability of the SL scalings for the design and fabrications of plasma devices.
Improving reaching with functional electrical stimulation by incorporating stiffness modulation
Authors: Johnson Tyler , Taylor Dawn 
Published: October 2021

Abstract

Objective. Intracortical recordings have now been combined with functional electrical stimulation (FES) of arm/hand muscles to demonstrate restoration of upper-limb function after spinal cord injury. However, for each desired limb position decoded from the brain, there are multiple combinations of muscle stimulation levels that can produce that position. The objective of this simulation study is to explore how modulating the amount of coactivation of antagonist muscles during FES can impact reaching performance and energy usage. Stiffening the limb by cocontracting antagonist muscles makes the limb more resistant to perturbation. Minimizing cocontraction saves energy and reduces fatigue. Approach. Prior demonstrations of reaching via FES used a fixed empirically-derived lookup table for each joint that defined the muscle stimulation levels that would position the limb at the desired joint angle decoded from the brain at each timestep. This study expands on that previous work by using simulations to: (a) test the feasibility of controlling arm reaching using a suite of lookup tables with varying levels of cocontraction instead of a single fixed lookup table for each joint, (b) optimize a simple function for automatically switching between these different cocontraction tables using only the desired kinematic information already being decoded from the brain, and (c) compare energy savings and movement performance when using the optimized function to automatically modulate cocontraction during reaching versus using the best fixed level of cocontraction. Main results. Our data suggests energy usage and/or movement performance can be significantly improved by dynamically modulating limb stiffness using our multi-table method and a simple function that determines cocontraction level based on decoded endpoint speed and its derivative. Significance. By demonstrating how modulating cocontraction can reduce energy usage while maintaining or even improving movement performance, this study makes brain-controlled FES a more viable option for restoration of reaching after paralysis.
A state-informed stimulation approach with real-time estimation of the instantaneous phase of neural oscillations by a Kalman filter
Authors: Onojima Takayuki , Kitajo Keiichi 
Published: October 2021

Abstract

Objective. We propose a novel method to estimate the instantaneous oscillatory phase to implement a real-time system for state-informed sensory stimulation in electroencephalography (EEG) experiments. Approach. The method uses Kalman filter-based prediction to estimate current and future EEG signals. We tested the performance of our method in a real-time situation. Main results. Our method showed higher accuracy in predicting the EEG phase than the conventional autoregressive (AR) model-based method. Significance. A Kalman filter allows us to easily estimate the instantaneous phase of EEG oscillations based on the automatically estimated AR model implemented in a real-time signal processing machine. The proposed method has a potential for versatile applications targeting the modulation of EEG phase dynamics and the plasticity of brain networks in relation to perceptual or cognitive functions.
1286 3D Printing of Aortic Valve Scaffolds for Heart Valve Regeneration
Authors: Georgi M , Ataide-Da Costa M , Saberi S E M , Wu L , Ma H , Darbyshire A , Sciscione F , Hamilton G , Song W H 
Published: October 2021

Abstract

Introduction
Valvular heart disease (VHD) has been commonly described as the forgotten epidemic, with an estimated global prevalence of 2.5%. Current heart valve replacement therapies only partially offer a solution to the problem. In recent years, synthetic polymers have been explored due to their diversity allowing tailor-picking of essential traits, such as chemical properties, physical properties, and degradation states. This project investigated the feasibility and mechanical properties of reverse three-dimensional printing of biodegradable scaffolds for heart valve regeneration.

Method
Aortic valve dimensions at an average of 100mmHg were used for the computer aided design of the valves. Aortic valve scaffolds were fabricated using the 3D-TIPs reverse printing technique. Infill densities of 30%, 40% or 50% were used. Printed polymer scaffolds were coated in gelatine solution and compared using static tensile tests. Static strength and elasticity of coated and uncoated valves were compared.

Results
At 25%, 50% and 100% strain, significantly different elastic properties in favour of coated scaffolds between coated and uncoated valves was observed. Coated valves displayed greater strength than uncoated valves (p &gt; 0.05). Computer aided design (CAD) software designed anatomically accurate scaffolds, but poor polymer coagulation was observed on the valve cusps.

Conclusions
The reverse-printing 3D-TIPS procedure successfully produces heart valve scaffolds which present architectural similarities to the naïve mitral valve, however, dimensions of the valves ought to be reassessed. Gelatine-coated valves exhibit greater elastic and tensile properties. A further understanding of cellular interactions on the polymer scaffold, in particular in vivo studies, are required for the continuity of future study.
129 Compliance with The ERAS Protocol Amongst Colorectal Surgery Junior Doctors at Gloucester Royal Hospital
Authors: Brennan L 
Published: October 2021

Abstract

Background
Enhanced recovery after surgery (ERAS) is an evidence-based protocol aiming to expedite recovery following elective surgical procedures. ERAS has shown to reduce the length of hospital stay, complications, readmissions, and costs. The junior doctor’s role in ERAS centres around admission, preoperative nutritional care, and ERAS compliance. This audit aimed to review prescribing of perioperative nutritional drinks (NutriciaPreop© and Fortisips) and intravenous fluids for patients undergoing elective colorectal surgery at Gloucester Royal Hospital.

Method
An 80% standard was set for this audit. A full audit cycle was completed. Drug and intravenous fluid charts were analysed for correct prescribing of NutriciaPreop© and intravenous fluids pre-operatively, and peri operative Fortisips. Improvement measures included ward posters and education to incoming junior doctors.

Results
Initial data collection showed that 70% of patients received a correct intravenous fluid prescription pre-operatively. 24% of patients were prescribed NutriciaPreop© and 18% were prescribed Fortisips. During re-auditing intravenous fluids were correctly prescribed in 80% of patients, NutriciaPreop© in 67% of patients and Fortisips in 60%.

Conclusions
This audit emphasises the importance of good quality inductions for junior doctors and how simple measures improve prescribing of essential peri-operative nutrition. Additionally, the value of multidisciplinary team involvement in junior doctor training has been highlighted.
161 Current Practice of Antibiotic Prescription in Acute Uncomplicated Diverticulitis
Authors: Patel M , Darwish N , Kirmani N 
Published: October 2021

Abstract

Aim
To review the current antibiotic prescribing practice for patients with acute uncomplicated diverticulitis against the NICE guidelines November 2019, to avoid unnecessary/overuse of antibiotics.

Method
A retrospective review of patients presenting with lower abdominal pain between 1/11/2019 -31/1/2020. All patients with suspected diverticulitis were included. Patients who were subsequently diagnosed with complicated diverticulitis/alternate diagnosis were excluded from the analysis.

Results
22/27 (81.5%) of the patients were admitted. 26 out of 27 (96.3%) patients with acute uncomplicated diverticulitis were administered antibiotics. Antibiotics were indicated as per NICE guidelines in 17 patients (62.97%) and not indicated in 9 patients (33.34%). Admission was not indicated in 20 patients (90.91%) according to NICE guidelines.

Conclusions
Our adherence to NICE guidelines is 66.67% in terms of antibiotic administration, however the drug and duration of antibiotic administration needs to be reviewed.
NICE guidelines recommend that acute uncomplicated diverticulitis can be managed as an outpatient. Antibiotics should be administered only if patient is systemically unwell, is immunosupressed or has significant co morbidities
197 Perioperative Diabetic Medication Prescribing- Adherence to Local Guidelines
Authors: De Rome K , Yalamanchili G , Asadi N 
Published: October 2021

Abstract

Aim
Optimization of diabetic medications around the time of operation is critical to avoid complications, hence we aimed to conduct an audit to review perioperative diabetic medication prescribing.

Method
Drug charts for peri-operative cardiac and thoracic patients were reviewed retrospectively on Medchart, a local electronic system used for prescribing medications. The omission or adjustment of oral anti-diabetic medications and insulin prescriptions were recorded.

Results
Over a one-month period, the prescriptions of 104 patients were recorded with an average age of 65.8 and out of which 21 patients were diabetic.

Conclusions
Our Audit demonstrated errors in perioperative diabetic medication prescribing. We focused our intervention by circulating a poster depicting the guidelines around the doctors and ANP offices. We did a re-audit in two months’ time to check the adherence.
These are the findings we found in the re-audit for 101 patients: -
239 An Audit on The Consenting Process For Orthopaedic Surgery During The COVID Pandemic
Authors: Manoharan G , Edakalathur J , Akhbari P , Potter R 
Published: October 2021

Abstract

Aim
The Royal College of Surgeons have published guidelines on consenting for treatment of patients when COVID-19 is present in society. Patients should be made aware that attending hospital for elective surgical procedures exposes them to the risk of contracting COVID-19, despite the stringent health and hygiene measures employed by hospitals and their staff. Our aim is to investigate whether orthopaedic patients are being appropriately consented for surgery during the COVID pandemic.

Method
A prospective audit of 100 consent forms was performed. The forms were examined to identify whether COVID-19 risk was documented as a potential risk of surgery. Data was also collected on consented grade, patient length of stay and any complications post-operatively.

Results
56% of consent forms reviewed did not contain the risk of COVID documented in them. 34% of forms that did not state COVID risk were completed by consultants, 18% by fellows and 48% were by registrars. 24% of these patients had an in-patient length of stay of 3 or more days. 6% patients were suspected of COVID post-operatively and tested. 0% patients contracted COVID in this cohort.

Conclusions
The Royal College of Surgeons COVID-19 Toolkit states that the risk of contracting COVID while in hospital is 0.45%. All patients should be made aware of this risk prior to proceeding with surgery. Only 44% of patients in our hospital have had this risk discussed and documented. This compliance level has to be significantly improved.