bluuebunny/crossref_metadata_2025 huggingface dataset:
Prevalence of Bleeding and Thrombosis in Critically Ill Patients with Chronic Liver Disease
Authors: Ow Tsai-Wing , Fatourou Evangelia , Rabinowich Liane , van den Boom Bente , Nair Shrijit , Patel Vishal C. , Hogan Brian , McPhail Mark , Roberts Lara N. , Bernal William
Published: October 2021

Introduction Hemorrhage and venous thromboembolism (VTE) are recognized complications of chronic liver disease (CLD), but their prevalence and risk factors in critically ill patients are uncertain.

Patients and Methods We studied a retrospective cohort of patients with CLD nonelectively admitted to a specialist intensive care unit (ICU) determining the prevalence and timing of major bleeding and VTE (early, present on admission/diagnosed within 48 hours; later, diagnosed >48 hours post-ICU admission). Associations with baseline clinical and laboratory characteristics, multiorgan failure (MOF), blood product administration, and mortality were explored. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using logistic regression.

Results Of 623 patients with median age 52, bleeding (>48 hours after admission) occurred in 87 (14%) patients. Bleeding was associated with greater illness severity and increased mortality. Gastrointestinal bleeding accounted for 72% of events, secondary to portal hypertension in >90%. Procedure-related bleeding was uncommon. VTE occurred in 125 (20%) patients: early VTE in 80 (13%) and involving the portal vein in 85%. Later VTE affected 45 (7.2%) patients. Hepatocellular carcinoma (HCC) and nonalcoholic liver disease were independently associated with early VTE (OR: 2.79, 95% CI: 1.5–5.2 and OR: 2.32, 95% CI: 1.4–3.9, respectively), and HCC, sepsis, and cryoprecipitate use with late VTE (OR: 2.45, 95% CI: 1.11–5.43; OR: 2.26, 95% CI: 1.2–4.3; and OR: 2.60, 95% CI: 1.3–5.1).

Conclusion VTE was prevalent on admission to critical care and less commonly developed later. Bleeding was associated with MOF and increased mortality. Severe MOF was not associated with an increased rate of VTE which was linked with HCC, and specific etiologies of CLD.
Efficacy of Subcutaneous Closed Suction Drain in Reduction of Postoperative Surgical Site Infection
Authors: Harish R. , Kazi Farah Naaz , Sharma J.V. Pranav
Published: October 2021

Background Surgical site infections (SSIs) are the infections of wound after an invasive operative approach. It remains to be a major morbidity for patients undergoing surgeries although there have been tremendous improvements in the surgical techniques.

Different interventions to suppress the selective serotonin reuptake inhibitors have been proposed. Many of them have been routinely used by surgeons like minimizing shaving, hand washing, and preoperative antibiotics and these are well accepted. Drains are used in major abdominal surgeries, hernia repairs, breast surgeries reducing collections in closed areas.1 Hematoma, serous fluid, and dead space in surgical incision wounds raise the risk of infection as they serve as the platform for microbial growth. Studies have proved that the usage of subcutaneous drains has lowered the chances of infection.

Results The patients in the case group had lower incidence of SSI compared with the control group. The patients in the case group had subcutaneous drain which drained any collection that developed in the subcutaneous space. When the incidence of SSI was compared between the emergency cases and elective cases, the emergency cases showed higher propensity for SSI and increased rate for patients who had co-morbidities like diabetes mellitus, hypertension, etc. The most common organism isolated from the SSI was found to be Escherichia coli. It was also noted that the mean number of days of hospital stay was comparatively higher for the patients who developed SSI compared with patients who did not develop SSI.

Conclusion Thus the presence of SSI adds morbidity to the patient and the patients who undergo major surgeries are likely to develop SSI postoperatively. The presence of subcutaneous closed suction drain helps in reducing the SSI to a certain extent.
Fragmentation of a liquid metal droplet falling in a water pool
Authors: Hadj-Achour M. , Rimbert N. , Gradeck M. , Meignen R.
Published: October 2021

This paper focuses on the experimental investigation of breakup regimes of a molten fusible metallic droplet in water, at intermediate Weber numbers with emphasis on mass and energy balance. The experiment consists in impacting perpendicularly a molten drop onto the interface of a deep water pool, at a controlled temperature. Using a drop-on-demand device and high-speed shadowgraph, a single drop can be visualized during its evolution. There is a noticeable velocity jump when the droplet crosses the interface that can be modeled using an unsteady Bernoulli equation. As observed for liquid–gas systems, the drop experiences different regimes of fragmentation, depending on its Weber number: oscillations, bag oscillations, prolate drop stretching breakup, and then bowl-shaped bag breakup. However, opposite to the gas–liquid case, a Rayleigh–Taylor instability mechanism seems to be absent and this seems related to the bowl-shaped bag breakup mechanism when compared to the dome-shaped gas–liquid case. Statistics of the daughter droplets are then given, using either image analysis for large droplets size distribution or sieving and weighting of the solidified fragments for measurement of the Sauter mean diameter and surface energy creation. Finally, a simple relation between the Sauter mean diameter and the Weber number is presented based on the energy and mass balances. When comparing with previous higher Weber number results, a viscous transition corresponding to a strong increase in the energy loss is also shown to occur for the higher Weber number.
Effect of heating on topology of vortex breakdown in Vogel–Escudier flow
Authors: Vishnu R. , Sharma Manjul , Sameen A.
Published: October 2021

This paper examines the effect of unstable thermal stratification on vortex breakdown in Vogel–Escudier flow. A three-dimensional direct numerical simulation of Navier–Stokes and energy equations are used to simulate a flow inside a cylindrical container generated by rotating the top lid. The top and bottom are kept at two constant temperatures such that unstable stratification is maintained. The rotation speed is related to the Reynolds number (Re), and buoyancy is linked to the Rayleigh number (Ra). The streamline and vertical velocity contour plots indicate different regimes of the flow depending on the Re and Ra. The convection dominated (CD) regime has a characteristic large-scale circulation similar to the Rayleigh–Bénard convection, and the rotation dominated (RD) regime has a central axial vortex and breakdowns. A transitional regime between RD and CD regimes is also identified from energy consideration. The influence of Ra on a vortex breakdown bubble and its relation to azimuthal vorticity is investigated in detail. Consistent with the literature on Vogel–Escudier flow, the azimuthal vorticity is shown to be essential for the breakdown in the presence of buoyancy as well. In the low Re limits, the energy of flow tends to be associated with the r–z plane velocity field, while at large Re, the energy is associated with the out-of-the-plane velocity field. Thermal plumes align along the axis for large rotations and are affected by the vortex breakdown bubble. The velocity perturbation structures and plumes show a remarkable distinction between rotation and convection-dominated regimes in the topology.
A novel local-variable-based Reynolds-averaged Navier–Stokes closure model for bypass and laminar separation induced transition
Authors: Li Yi , Xu Jiakuan , Qiao Lei , Zhang Yang , Bai Junqiang
Published: October 2021

A one-equation Reynolds-averaged Navier–Stokes closure model is established for bypass transition in this paper. A new local indicator is proposed to describe the variation of turbulence intensities and pressure gradients. Based on this new indicator, a novel and efficient transition criterion is formulated. For laminar separation bubble induced transition, a reasonable modified intermittency factor is developed to complete the reattachment process and control the size of separation bubbles. Incorporated with Menter's k−ω shear stress transport turbulence model, the new transition-turbulence model is built for a high turbulence intensity environment. Several classical flow cases, including the ERCOFTAC (European Research Community on Flow, Turbulence and Combustion) series flat plates with various pressure gradients, the Pratt and Whitney low pressure turbine cascade, and a highly loaded linear compressor cascade, are all employed for the model verifications. Decent agreement with the experimental data and direct numerical simulation data can be obtained in a wide range of incoming flow conditions.
The influence of micro vortex generator on inception cavitation
Authors: Chen Jie , Hu Changli , Zhang Mengjie , Huang Biao , Zhang Hanzhe
Published: October 2021

The objective of the present paper is to investigate the influence of the micro vortex generator (mVG) on the inception cavitation number and mode around a National Advisory Committee for Aeronautics 66 hydrofoil. Two different sets of mVG with varying position are employed in this paper, i.e., the mVG-1 (located upstream of the laminar separation point of the baseline hydrofoil) and the mVG-2 (located in the laminar separation zone of the baseline hydrofoil). A high-speed camera is applied to visualize the inception cavitating structures, and numerical simulation is assisted to the effect of mVG. The results indicate that compared to the baseline hydrofoil, the mVG-1 can promote the earlier inception cavitation while the mVG-2 delays the inception, especially for the cases with smaller angle of attack (α = 4°–8°). For the mVG-1 hydrofoil, there are two reasons to be responsible for this phenomenon. One is that the fingerlike vortex at the rear of mVG-1 induces the fingerlike vortex cavitation earlier. The other is that the mVG-1 increases the length of the laminar separation bubble (LSB) by comparison with the baseline hydrofoil, thus causing a cavitation due to the laminar boundary layer separation. For the mVG-2 hydrofoil, it is located at the high-pressure zone of leading edge and reduces the length of the LSB. More precisely, the fingerlike vortex in the high-pressure zone is not enough to induce a fingerlike vortex cavitation, and the smaller length of the LSB than that of the baseline hydrofoil suppressing the cavitation at some angles of attack.
Parameter optimization of open-loop control of a circular cylinder by simplified reinforcement learning
Authors: Lai Pengyu , Wang Rui , Zhang Wei , Xu Hui
Published: October 2021

Open-loop control is commonly considered an efficient approach in flow control, in which the search for control parameters with excellent performance is mostly carried out by grid search, leading to an extremely tedious process of parameter optimization. With extensive applications of machine learning, reinforcement learning (RL) has emerged as a powerful tool to achieve optimal strategies, which constructively leads to the result that parameter optimization can be performed by RL. In this paper, we provide the concept of simplified RL formally and show the corresponding properties. In order to implement simplified RL for flow control, a high-order numerical approach is coupled with simplified RL to develop a new framework for parameter optimization and determination. In order to validate the performance of the framework, flows past a rotary oscillating circular cylinder at low Reynolds number Re = 200 (defined as Re=U∞D/ν, where U∞ is the free-stream velocity and ν is the kinematic viscosity) are investigated by varying the parameters of rotary amplitude and frequency individually or simultaneously. By numerical investigations, a satisfactory drag reduction effect is achieved, which demonstrates the capability of the framework to perform parameter optimization in terms of open-loop control.
On a vertical chain of small bubbles ascending in a viscoelastic fluid
Authors: Yuan Wenjun , Zhang Mengqi , Khoo Boo Cheong , Phan-Thien Nhan
Published: October 2021

Recently, our direct numerical simulations [Yuan et al., “Hydrodynamic interaction and coalescence of two inline bubbles rising in a viscoelastic liquid,” Phys. Fluids 33, 083102 (2021)] indicated that a stable chain can be formed for a pair of bubbles rising in a viscoelastic liquid, consistent with experimental observations. Motivated by the fact that the flow in bubble chains is still poorly understood, this Letter extends the investigations to multiple small bubbles ascending in a vertical file in a viscoelastic medium with different configurations. With an increasing bubble number, it is found that the rising velocity of the bubble group increases and the vertical chain of bubbles becomes unstable due to the distinct oscillation of the uppermost bubble. The terminal separation distance between two adjacent bubbles decreases in the upward direction, diminished by the neighborhood rising bubbles due to increasing loading. By probing the polymeric stresses and deformation, our results demonstrated that the accumulation of viscoelastic normal stresses promotes the aggregation of rising bubbles, while the successive chain of bubbles is stable because of the near-field repulsion induced by the non-monotonic polymer stretching among the bubble chain. In addition, the large bubble deformation appears to enhance the accumulative polymeric normal stress effect, and the bubbles can form more stable vertical chains at increasing initial spacing. Our findings provide insights into the mechanism of bubbles clustering in viscoelastic fluids, as chaining of bubbles is believed to be more prevailing in highly elastic flows.
Investigating the absorption performance of a monolayer-coated absorber at oblique incidence
Authors: Zhang Junming , Liu Chang , Wang Tao , Li Fashen
Published: October 2021

There is a widely observed phenomenon in the microwave absorption field that an absorber always exhibits good oblique incidence absorption capacity if it has high performance at normal incidence. However, if a certain angle is exceeded, this kind of effective absorptive capacity will no longer be maintained. Besides, an absorber performs differently for incident transverse electric (TE) and transverse magnetic (TM) waves: for the TE case, the absorber can no longer obtain effective absorption; for the TM case, another efficient absorption region was observed at higher frequencies even when the incident angle exceeded 80°. These phenomena are widely found in the literature, which demonstrates that they are caused by physical laws rather than material properties. To demonstrate the underlying reason, in this study, the common spherical carbonyl iron-polyurethane composite absorbers were fabricated as a typical example. Their absorbing performance was investigated via both simulation and experiment. All the phenomena mentioned above were observed, studied in detail by employing the multiple reflection model, and explained quantitatively. Further, along with establishing the underlying mechanism of electromagnetic wave transmission in the absorber, two formulas were deduced to predict: (a) the maximum incident angle for efficient absorption of the TE polarized wave; and (b) the required absorber thickness for obtaining efficient absorption for a large incident angle of the TM polarized wave.
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

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

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

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

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

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

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

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

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

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

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

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 > 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

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

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

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

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.
416 Hyperlipasaemia In an Adult Hospital Population: A Retrospective Audit Demonstrating A High Proportion of Non-Pancreatic Causes of a Diagnostically Raised Lipase
Authors: Yao L , Briggs C , Labib P
Published: October 2021

Introduction

Serum lipase is considered to be a more specific test than amylase for acute pancreatitis, and a rise of over three times the laboratory upper limit of normal (ULN) is considered diagnostic. This single-centre retrospective audit assessed the accuracy of a raised lipase in confirming acute pancreatitis.

Method

All patients with a raised lipase (>78 U/L) admitted over one month were reviewed. Patients whose lipase was measured >48 hours after admission were excluded. Cross-sectional imaging and discharge summaries were reviewed to determine the cause of hyperlipasaemia. Receiver Operator Characteristics (ROC) analysis was performed to determine the most accurate cut-off value for diagnosing acute pancreatitis.

Results

Ninety-nine patients were included. The most common causes of raised lipase (>78 U/L) were pancreatitis (37%), hepatobiliary (15%), gastroduodenal (8%) and renal (8%) disease. In patients with a lipase >234 U/L (3xULN, n = 46), the most common causes were pancreatitis (70%), drugs (9%), hepatobiliary (9%), gastroduodenal (4%) and renal (4%) disease. ROC analysis showed lipase to have an area under the curve (AUC) of 0.89 (95% CI 0.84-0.96, p < 0.0001). Using the laboratory cut-off of 234 U/L (3xULN), lipase had a sensitivity, specificity, and positive likelihood ratio (PLR) of 86.5%, 77.4% and 3.8. Increasing the lipase cut-off did not improve the specificity without compromising the sensitivity of the test.

Conclusions

A lipase cut-off of 3xULN is an appropriate cut-off for a biochemical diagnosis of acute pancreatitis. However, up to 30% of patients with lipase values above this cut-off may have alternative diagnoses that should be considered.
434 Incidence of Normal Colonoscopy in Faecal Immunochemical Test (FIT) Positive Patients in The Colorectal 2-Week-Wait (2WW) Pathway at A District General Hospital (DGH)
Authors: Al-Habsi R , Divya G S , Hemandas A
Published: October 2021

Introduction

FIT is a quantitative, highly specific test to detect blood in stool for malignant and non-malignant colorectal diagnoses. Incidence of normal colonoscopy following positive FIT is not widely reported. We conducted a retrospective audit to analyse this patient cohort to evaluate diagnostic accuracy and reporting standards of colonoscopy.

Method

FIT-positive was defined as > 10µgHb/g faeces. Using FIT value, patients were separated into Groups 1, 2 and 3: 10-99, 100-200 and >200µgHb/g faeces respectively. Normal colonoscopy was defined as no neoplastic or benign findings reported. Patients referred in the 2WW-pathway after introduction of FIT-testing in October 2019 to the onset of COVID-19 pandemic in March 2020 were included. Data on age, gender, comorbidities and additional investigations were collected.

Results

There were 1072 referrals in the study period; 405 had FIT done, 265 were FIT-positive and had colonoscopy referral. Four patients were excluded after further investigations showed diverticulosis and gastritis. FIT-stratified normal-colonoscopy rate was 13.3% (28/210) overall, and 14.1% (23/163), 16.7% (2/12) and 8.6% (3/35) for Group 1, 2 and 3 respectively.

Conclusions

Our study was limited by the onset of COVID-19 pandemic. In the short study period, 13.3% FIT-positive patients had normal colonoscopy. There are no comparative data in literature for this parameter. Higher FIT-values were associated with lower normal colonoscopy incidence. It is possible that some endoscopists failed to record positive, non-clinically significant findings. We are currently studying larger patient cohorts and in parallel, looking at Bowel Cancer Screening Programme (BCSP) patients.
449 Burden of Epistaxis - Room for Improvement?
Authors: Ash J , Faoury M , Eze N
Published: October 2021

Aim

We conducted an audit at a large tertiary hospital of the measures and information given to patients admitted with Epistaxis. The aim of this audit was to identify factors for prolonged inpatient admissions and elucidate the extent of patient suitable information provided.

Method

A retrospective audit was conducted collecting data over two months on all patients admitted with epistaxis. Data was collected on demographics, co-morbidities, length of stay, discussions with other specialities and the extent (verbal/written) of information given to patients with regard to management of epistaxis in the community and how to reduce the risk of further episodes of epistaxis.

Results

Sixty patients were identified with an average age of 68 years. The patients were inpatients for an average of 41 hours. 10% had a form of haematological disorder, 40% were on warfarin/DOAC and 45% had hypertension. 40% had neither verbal nor written information given about either management or reducing risk. 10% had written information about both. 8% were re-admitted within 30 days of discharge and 17% had previously been admitted with epistaxis in the last 6 months.

Conclusions

Epistaxis is a common inpatient admission in ENT with a significant bed burden on the department. A significant proportion of patients are co-morbid and thus easily understandable trust guidelines on management of epistaxis on warfarin/doac should be available to reduce length of stay. The low proportion of patients provided with information to help self-care is significant and is likely to play an important role in the re-admission rates.
475 An Audit to Assess Contact Information for Outpatient Emergency Trauma Patients
Authors: Hadi H , Smith A
Published: October 2021

Aim

To recognise if there is a discrepancy between contact information on our electronic system and those obtained by the clinician.

Introduction

Patients are clerked during the orthopaedic on-call and discharged with the possibility of requiring urgent outpatient surgery. These patients are contacted by the trauma co-ordinator prior to their operation date. It is common practice in orthopaedics for the clinician to obtain the most up to date contact information during the on-call clerking. There are occasions where patients are unable to be contacted prior to surgery due to insufficient contact information. This audit is to identify if there is a discrepancy between contact information on the electronic system compared to that obtained during the clerking.

Method

Contact information for all patients clerked by the on-call team over 14 days during Nov 2019 were reviewed. They were categorised into 3 groups; ‘clinician obtained further information’, ‘electronic system had more information’ and ‘no discrepancy’.

Results

Data was collected for 71 patients. The results showed that the clinician obtained further information for 18 patients (25.3%). The electronic system had more information in 16 patients (22.5%). There was no discrepancy in 37 patients (52.1%).

Discussion

This audit has highlighted an issue, as the results show 25% of patient contact information is incomplete. Given these patients are seen in the emergency setting, this is the only opportunity to obtain correct information to continue the management of patient care. This is paramount to streamline theatre flow and optimise the use of available theatre slots.
490 5-Year Follow-up of Periocular Primary Basal Cell Carcinoma at Burnley General Teaching Hospital
Authors: Lu Y , Usmani H , Fernando B
Published: October 2021

Aim

(1) To investigate the recurrence rate of periocular primary basal cell carcinoma (pBCC) in Burnley General Teaching Hospital (BGTH). (2) To compare the recurrence rate of periocular pBCC in our centre with the standards published by the British Association of Dermatologists (BAD).

Method

A retrospective cohort study was carried out. Inclusion criterion was all patients undergoing surgical excision of periocular pBCC in BGTH between January 2011 to December 2016. Electronic records were reviewed, and the recurrence rate locally was then calculated and compared with the 2% stated in the BAD guidelines [1].

Results

A total of 197 cases met the audit inclusion criteria over the period of 5 years at BGTH. All of them completed 5 years of follow-up. The mean age of the selected population was 75.7 years (SD 12.77). Male:female ratio was 104:93. Only one case was identified as recurrent primary BCC, which makes the recurrence rate of this audit 0.5% (1/197).

Conclusions

This audit confirmed that the recurrence rate of periocular pBCC after margin section control achieved the standard set by BAD guidelines. The reason might be that reconstruction is performed after the confirmation of marginal clearance. Although the recommended treatment for pBCC is MMS, it is not available in every centre. However, patients need to wait at least one week for the reconstruction after margin section control. The limitation of this audit includes the data of the size and anatomical site were incomplete for all patients due to inconsistent histology reports.