bluuebunny/crossref_metadata_2025 huggingface dataset:
Energy conversion mechanisms of a seesaw-type energy harvester
Authors: Zhong Xiang , Wang Buyi , Li Rong , Wu Yimin , Ma Mengchao , Deng Huaxia
Published: February 2022

Vibration energy harvesters with bistable characteristics, which can convert mechanical energy to electric energy, are typically cantilever beams with magnetic repulsion. In order to enhance their low-frequency performance, a seesaw-type approach has been proposed, which can make the structure overcome the potential barrier more easily. In this paper, we establish electromechanical coupling equations of the whole system, and prove that the internal beam delivers mechanical energy to the primary beam based on time-domain analysis. Meanwhile, frequency-domain analysis and solutions are conducted to investigate the dynamical and electrical behaviors of the system based on the adjustment of different parameters. We find that both the mechanical and electrical responses are enhanced gradually with the decrease of the relative damping coefficient within the bounds of the discussion. And the maximum response amplitude can be increased by a factor of 11.3 just by adjusting the position of the internal beam. Furthermore, the length of the internal beam can affect the responses of the system visibly and regularly, and the maximum response amplitude remains unchanged when changing the length of the internal beam from 80 to 100 mm. All of this suggests that the mechanisms of a seesaw-type energy harvester will provide guidance for designing a more appropriate structure, depending on different applications.
Modulation of the dielectric property of Ga2O3/TiO2 nanolaminates and their improvement on the electroluminescence from devices based on Er-doped Al2O3 nanofilms
Authors: Yuan Kang , Ma Rui , Yang Li , Yang Yang , Sun Jiaming
Published: February 2022

Metal-oxide-semiconductor light-emitting devices (MOSLEDs) based on the erbium doped Al2O3 nanofilms still suffer from insufficient and unstable electrical injection, and the dielectric protection layers play an important role in their performance. Here, Ga2O3/TiO2 (GTO) nanolaminate films are fabricated by atomic layer deposition, the dielectric constant and leakage current of which are gradually regulated by alternating the component ratios. The tolerance to electric field and electron injection for the Al2O3:Er MOSLEDs is significantly improved, leading to the enhanced electroluminescence performance. The optimal GTO nanolaminate with thickness ratio of 4:6 could withstand the maximum breakdown electric field reaching 4.17 MV cm−1 while maintaining a high electric field of 8.4 ± 0.1 MV cm−1 within the luminescent Al2O3:Er layer (under injection of 0.3 A cm−2), resulting in the optical power density up to 11.37 mW cm−2. Much higher excitation efficiencies are also achieved with external quantum efficiency of 19.35%, and the operation time of the prototype Al2O3:Er MOSLEDs is significantly enhanced by more than two orders of magnitude from 48 s (I= 0.2 μA) to 7308 s (I = 1 μA). The design principle of the dielectric nanolaminates has been deduced, considering the dielectric and conductive contribution of different oxides, which supplies a promising route to further explore the application of optoelectronic devices based on oxides.
Raman scattering studies of the ambient atmospheric thermal stability of Be in periodic Be/Mo and Be/W multilayer mirrors
Authors: Kumar Niranjan , Antisheva Galina D , Nezhdanov Aleksey V , Drozdov Mikhail N , Pleshkov Roman S , Yunin Pavel A , Polkovnikov Vladimir N , Chkhalo Nikolay I
Published: February 2022

The ambient atmospheric thermal stability of beryllium (Be) layers in Be/Mo and Be/W multilayer mirrors was investigated by Raman scattering. The physical characteristic of the transverse optical (TO) mode was considered for structural analysis of the Be layers in the multilayers. With an increase in thermal annealing temperature, two important modifications of this mode were noticed: the TO mode of Be was found to shift to a lower frequency and the peak width became wider. These two facts are related to the deterioration of the crystalline quality of the Be layers upon thermal annealing. The TO mode of the crystalline Be phase completely vanished and high-intensity peaks at the shoulder were detected for the Be/Mo multilayer thermally annealed at 723 K. This evidence is associated with the transformation of polycrystalline into an oxidized amorphous Be phase. In this case, the diffusion of oxygen to the inner period and the destruction of the modulation of the periodic structure of the multilayer was investigated by a secondary ion mass spectrometer. However, the TO mode of Be embedded within W in Be/W multilayers was stable in similar annealing conditions, which revealed the thermal stability.
Dynamics of two-dimensional liquid bridges
Authors: Coelho Rodrigo C V , Cordeiro Luís A R G , Gazola Rodrigo B , Teixeira Paulo I C
Published: February 2022

We have simulated the motion of a single vertical, two-dimensional liquid bridge spanning the gap between two flat, horizontal solid substrates of given wettabilities, using a multicomponent pseudopotential lattice Boltzmann method. For this simple geometry, the Young–Laplace equation can be solved (quasi-)analytically to yield the equilibrium bridge shape under gravity, which provides a check on the validity of the numerical method. In steady-state conditions, we calculate the drag force exerted by the moving bridge on the confining substrates as a function of its velocity, for different contact angles and Bond numbers. We also study how the bridge deforms as it moves, as parametrized by the changes in the advancing and receding contact angles at the substrates relative to their equilibrium values. Finally, starting from a bridge within the range of contact angles and Bond numbers in which it can exist at equilibrium, we investigate how fast it must move in order to break up.
Superconducting dome associated with the suppression and re-emergence of charge density wave states upon sulfur substitution in CuIr2Te4 chalcogenides
Authors: Boubeche Mebrouka , Wang Ningning , Sun Jianping , Yang Pengtao , Zeng Lingyong , Luo Shaojuan , He Yiyi , Yu Jia , Wang Meng , Cheng Jinguang , Luo Huixia
Published: February 2022

We report the path from the charge density wave (CDW)-bearing superconductor CuIr2Te4 to the metal insulator transition (MIT)-bearing compound CuIr2S4 by chemical alloying with the gradual substitution of S for Te. The evolution of structural and physical properties of the CuIr2Te4−x
S
x
(0 ⩽ x ⩽ 4) polycrystalline system is systemically examined. The x-ray diffraction (XRD) results imply CuIr2Te4−x
S
x
(0 ⩽ x ⩽ 0.5) crystallizes in a NiAs defected trigonal structure, whereas it adapts to the cubic spinel structure for 3.6 ⩽ x ⩽ 4 and it is a mixed phase in the doping range of 0.5 < x < 3.6. Unexpectedly, the resistivity and magnetization measurements reveal that small-concentration S substitution for Te can suppress the CDW transition, but it reappears around x = 0.2, and the CDW transition temperature enhances clearly as x augments for 0.2 ⩽ x ⩽ 0.5. Besides, the superconducting critical temperature (T
c) first increases with S doping content and then decreases after reaching a maximum T
c = 2.82 K for CuIr2Te3.85S0.15. MIT order has been observed in the spinel region (3.6 ⩽ x ⩽ 4) associated with T
MI increasing with x increasing. Finally, the rich electronic phase diagram of temperature versus x for this CuIr2Te4−x
S
x
system is assembled, where the superconducting dome is associated with the suppression and re-emergence of CDW as well as MIT states at the end upon sulfur substitution in the CuIr2Te4−x
S
x
chalcogenides.
Head and abdomen CT exposures in Portugal
Authors: Trindade Hugo , Barreira Marisa , Xavier Cláudia
Published: February 2022

In Portugal, computed tomography (CT) exposures for adult routine head, adult routine abdomen and paediatric abdomen (5 years old) were evaluated between 2019 and 2020 in 92 CT units. The third quartile value for CTDIvol was 63.2 mGy for adult head exams, 15.9 mGy for adult abdomen and 5.2 mGy for paediatric abdomen. However, the CTDIvol for head examination in 7.6% of units exceeded the suspension level proposed in EU report 162 while the number of units exceeding suspension levels for adult and paediatric abdomen were 3.2% and 0.0%, respectively. The used acquisition parameters and the referred CT unit’s specifications were studied to understand how radiation dose relates with tube voltage, tube current, rotation time, detector width, slice width, pitch value and the use of automatic exposure control (AEC). The axial acquisition mode was predominant (67%) in the head exams. However, the helical scanning was commonly used in abdomen exams. Dose reduction from adult to paediatric exams was achieved using a lower tube current (a 60% average reduction). AEC is preferably used in abdomen protocols (84% in adult exams and 96% in paediatric exams). Nonetheless, in adult routine head protocols only 27% used this system. Data was gathered from clinics and hospitals covered by this study which allowed an estimate of an annual frequency of 206 CT examinations per 1000 population in Portugal. The estimated dose index (CTDIvol) and frequency of CT examinations for the Portuguese population agreed with data from other countries.
Micropyramid structured photo capacitive interfaces
Authors: Nikić Marta , Opančar Aleksandar , Hartmann Florian , Migliaccio Ludovico , Jakešová Marie , Głowacki Eric Daniel , Đerek Vedran
Published: February 2022

Optically driven electronic neuromodulation devices are a novel tool in basic research and offer new prospects in medical therapeutic applications. Optimal operation of such devices requires efficient light capture and charge generation, effective electrical communication across the device’s bioelectronic interface, conformal adhesion to the target tissue, and mechanical stability of the device during the lifetime of the implant—all of which can be tuned by spatial structuring of the device. We demonstrate a 3D structured opto-bioelectronic device—an organic electrolytic photocapacitor spatially designed by depositing the active device layers on an inverted micropyramid-shaped substrate. Ultrathin, transparent, and flexible micropyramid-shaped foil was fabricated by chemical vapour deposition of parylene C on silicon moulds containing arrays of inverted micropyramids, followed by a peel-off procedure. The capacitive current delivered by the devices showed a strong dependency on the underlying spatial structure. The device performance was evaluated by numerical modelling. We propose that the developed numerical model can be used as a basis for the design of future functional 3D design of opto-bioelectronic devices and electrodes.
Improved analog switching characteristics of Ta2O5-based memristor using indium tin oxide buffer layer for neuromorphic computing
Authors: Lee Tae Sung , Choi Changhwan
Published: February 2022

A memristor is defined as a non-volatile memory switching two-terminal resistor, and a memristor with digital switching characteristics is widely studied as a next-generation non-volatile memory because of its simple structure, high integration density, and low power consumption. Recently, analog memristors with gradual resistance switching (RS) characteristics have garnered great attention because of their potential to implement artificial synapses that can emulate the brain functions. Transition metal oxides are thought to be strong candidate materials for the RS. In particular, tantalum oxide (TaO
x
)-based memristive devices provide stable and durable switching characteristics. TaO
x
-based memristors utilize analog switching characteristics and have excellent durability and reliability, so they can be applied as artificial synaptic device. In this study, the characteristics of analog RS using Ta2O5-based memristive devices were investigated. The current level of the Pt/Ta2O5/Pt memristors was improved by adjusting the thickness of Ta2O5. In particular, when an indium-tin-oxide (ITO) buffer layer was added to Ta2O5 forming a Pt/ITO/Ta2O5/Pt heterostructured double-layer device, it showed more symmetrical potentiation and depression characteristics under both polarities than a single-layer device without ITO layer. The symmetrical and linear potentiation and depression characteristics are essential for the development of efficient memristor-based neuromorphic systems. Insertion of the ITO buffer layer improves linearity, symmetry, and stability of the analog RS properties of Ta2O5-based memristors to artificial synapses.
Density functional theory study of nitrogen-doped black phosphorene doped with monatomic transition metals as high performance electrocatalysts for N2 reduction reaction
Authors: Liu Xin , Li Chenyin , Xu Fang , Fan Guohong , Xu Hong
Published: February 2022

Ammonia (NH3) is an essential resource in human production and living activities, and its demand has been rising in recent years. The catalytic synthesis of NH3 from N2 under mild conditions, inspired by biological nitrogen fixation, has piqued the interest of researchers. In this paper, density functional theory (DFT) calculations were used to investigate the catalytic activity, mechanism, and selectivity of the TM embedded nitrogen-doped phosphorene as high-performance nitrogen reduction reaction (NRR) electrocatalysts in depth. The results show that Nb- and Mo-doped catalysts present excellent catalytic performance, with low limiting potentials of −0.41 and −0.18 V, respectively. The Mo–N3–BP catalyst, for example, not only has an extremely low overpotential (−0.02 V), but also presents superior selectivity to effectively inhibit the HER competition reaction. A deeper look into the catalytic mechanism reveals a volcano relationship between the d-band center and the catalytic activity (Mo and Nb are located near the peak of the volcano-type curve). The d-band center and charge of the metal center can be regarded as effective descriptors for NRR activity on TM embedded nitrogen-doped phosphorene electrocatalysts, which hope to serve as a guiding principle for the design of high performance NRR single-atom catalyst in the future.
In-out charge exchange measurements and 3D modelling of diagnostic thermal neutrals to study edge poloidal impurity asymmetries
Authors: Cruz-Zabala D J , Viezzer E , Plank U , McDermott R M , Cavedon M , Fable E , Dux R , Cano-Megias P , Pütterich T , van Vuuren A Jansen , Garcia-Munoz M , Garcia Lopez J
Published: February 2022

A new method was developed to model the neutral population produced by the gas puff based charge exchange recombination spectroscopy systems at ASDEX Upgrade (AUG). With this method, the edge impurity density on the high field side (HFS) and low field side (LFS) can be obtained without the need to apply a neutral beam injection system. The neutral penetration needed for the calculation of the impurity density is obtained with a new gas puff module implemented in the FIDASIM code. The LFS impurity density profile evaluated with the new gas puff module matches the impurity density calculated with standard beam-based charge exchange diagnostics. Impurity temperature, rotation and density profiles at the HFS and LFS of an AUG H-mode discharge are presented. Edge impurity toroidal and poloidal flows show asymmetric structures. The impurity density asymmetries obtained with the new gas puff module are consistent with the observed flow structure.
Intrinsically shunted NbN/TaN/NbN Josephson junctions on Si substrates for large-scale integrated circuits applications
Authors: Yan Kaixin , Zhang Lu , Zhong Yulong , Shi Jiasheng , Shi Weifeng , Wu Ling , Wang Huiwu , Chen Lei , Ren Jie , Peng Wei , Wang Zhen
Published: February 2022

Superconducting circuits based on Josephson junctions have the potential to achieve high speed and ultra-low power consumption, but their integration is limited by the low controllability of Nb-based tunnel junction and the existence of shunt resistors. In this work, we report the fabrication of superconductor/normal metal/superconductor (SNS) Josephson junctions with high reproducibility on oxidized Si substrates. The junctions based on NbN/TaN/NbN trilayers measured at 4.2 K show excellent Josephson properties with a wide range of critical current (I
c) from 227 to 2000 μA. The variations of critical current density (J
c) and characteristic voltage (V
c) are respectively less than 7.1% and 7.5% in the 2 inch region. The standard deviation of I
c is calculated to be less than 1.7% for Josephson arrays with the number of junctions up to 10 000 occupying an area of 0.34 mm2. The results provide a guarantee for the applications of NbN-SNS Josephson junctions in superconducting large-scale integrated circuits.
A graphene inspired electromagnetic superlens
Authors: Lannebère Sylvain , Silveirinha Mário G
Published: February 2022

In this paper we propose a new paradigm to create superlenses inspired by n–p–n junctions of graphene. We show that by adjoining an n-type region and a p-type region with a crystal dislocation, it is possible to mimic the interaction of complementary Hamiltonians and achieve subwavelength imaging. We introduce an effective model of the system, and show that it predicts perfect lensing for both propagating and evanescent waves due to the excitation of a resonant mode at the interface between each region. This phenomenon is the consequence of a nontrivial boundary condition at the n–p interfaces due to a dislocation of the graphene ‘atoms’. We discuss practical realizations of such superlenses in electronic and photonic platforms. Using full wave simulations, we study in detail the performance of a photonic realization of the lens based on a honeycomb array of dielectric cylinders embedded in a metal.
Slow light frequency reference cavities—proof of concept for reducing the frequency sensitivity due to length fluctuations
Authors: Horvath Sebastian P , Shi Chunyan , Gustavsson David , Walther Andreas , Kinos Adam , Kröll Stefan , Rippe Lars
Published: February 2022

Length changes due to thermo-mechanical noise originating from, for example, Brownian motion are a key limiting factor of present day state-of-the-art laser frequency stabilization using Fabry–Pérot cavities. We present a laser-frequency stabilization concept using an optical cavity with a strong slow-light effect to reduce the impact of cavity length changes on the frequency stability. The resulting noise-reduction factor is proportional to the ratio between the light phase and group velocities in the highly dispersive cavity spacer. We experimentally demonstrate a proof-of-principle implementation of this laser-frequency stabilization technique using a rare-earth doped crystalline cavity spacer in conjunction with semi-permanent spectral tailoring to achieve precise control of the dispersive properties of the cavity. Compared to the same setup in the absence of the slow-light effect a reduction in frequency sensitivity of four orders of magnitude was achieved.
Symmetry analysis, optimal classification and dynamical structure of exact soliton solutions of (2+1)-dimensional modified Bogoyavlenskii–Schiff equation
Authors: Kumar Mukesh , Manju Kumari
Published: February 2022

The present research framework looks over complete sorted symmetry group classification and optimal subalgebras of (2+1)-dimensional modified Bogoyavlenskii-Schiff(mBSchiff) equation. It’s highly nonlinear and exhibits wave propagation in thermal pulse, sound wave, and bound particle. Using the invariance property of Lie groups, adequate infinitesimal symmetry of Lie algebra has been set up for the mBSchiff equation. A rigorous and systematized algorithm is carried out to obtain one optimal system based on the invariance feature of adjoint transformation. Further, symmetry reduction of the mBSchiff equation has been made to derive a system of ordinary differential equations with newly established similarity variables. The complete set of group invariant solutions for each corresponding subalgebras has been made. The derived solutions have diverse physical phenomena, which MATLAB simulation can quickly analyze. Thus, solutions presented here are kink, positon, soliton, doubly soliton, negaton, multisoliton types, which add on some meaningful physical aspects of the research.
A semi-supervised approach to dark matter
searches in direct detection data with machine learning
Authors: Herrero-Garcia Juan , Patrick Riley , Scaffidi Andre
Published: February 2022

The dark matter sector remains completely unknown. It is therefore crucial to keep an open mind regarding its nature and possible interactions. Focusing on the case of Weakly Interacting Massive Particles, in this work we make this general philosophy more concrete by applying modern machine learning techniques to dark matter direct detection. We do this by encoding and decoding the graphical representation of background events in the XENONnT experiment with a convolutional variational autoencoder. We describe a methodology that utilizes the `anomaly score' derived from the reconstruction loss of the convolutional variational autoencoder as well as a pre-trained standard convolutional neural network, in a semi-supervised fashion. Indeed, we observe that optimum results are obtained only when both unsupervised and supervised anomaly scores are considered together. A data set that has a higher proportion of anomaly score is deemed anomalous and deserves further investigation. Contrary to classical analyses, in principle all information about the events is used, preventing unnecessary information loss. Lastly, we demonstrate the reach of learning-focused anomaly detection in this context by comparing results with classical inference, observing that, if tuned properly, these techniques have the potential to outperform likelihood-based methods.
Testing the early universe with anisotropies of the gravitational wave background
Authors: Dimastrogiovanni Ema , Fasiello Matteo , Malhotra Ameek , Meerburg P. Daniel , Orlando Giorgio
Published: February 2022

In this work we analyse in detail the possibility of using small and intermediate-scale gravitational wave anisotropies to constrain the inflationary particle content. First, we develop a phenomenological approach focusing on anisotropies generated by primordial tensor-tensor-scalar and purely gravitational non-Gaussianities. We highlight the quantities that play a key role in determining the detectability of the signal. To amplify the power of anisotropies as a probe of early universe physics, we consider cross-correlations with CMB temperature anisotropies. We assess the size of the signal from inflationary interactions against so-called induced anisotropies. In order to arrive at realistic estimates, we obtain the projected constraints on the non-linear primordial parameter F
NL for several upcoming gravitational wave probes in the presence of the astrophysical gravitational wave background. We further illustrate our findings by considering a concrete inflationary realisation and use it to underscore a few subtleties in the phenomenological analysis.
Sputtering and reflection from a beryllium surface: effects of hydrogen isotope mass, impact position and surface binding energy
Authors: Shermukhamedov S. , Chen L. , Nazmutdinov Renat , Probst Michael
Published: February 2022

Atomistic simulations with machine-learned potential energy functions are employed for understanding the mechanisms driving the sputtering of beryllium by low-energy deuterium and tritium atoms and the details of their retention on pristine beryllium surfaces. The interaction between hydrogen/deuterium/tritium and beryllium surfaces regarding erosion yields is investigated by molecular dynamics simulations. The erosion yields of both hydrogen isotopes are similar for the same kinetic energies. Concentrating on deuterium, its impact on specific surface sites is analyzed. Finally, analytical expressions are used to predict the energy spectra of sputtered atoms.
Chondrogenic preconditioning of mesenchymal stem/stromal cells within a magnetic scaffold for osteochondral repair
Authors: Zhang Jiabin , Zhang Ming , Lin Rongcai , Du Yuguang , Wang Liming , Yao Qingqiang , Zannettino Andrew , Zhang Hu
Published: February 2022

Stem cell therapy using mesenchymal stem/stromal cells (MSCs) represents a novel approach to treating severe diseases, including osteoarthritis. However, the therapeutic benefit of MSCs is highly dependent on their differentiation state, which can be regulated by many factors. Herein, three-dimensional (3D) magnetic scaffolds were successfully fabricated by incorporating magnetic nanoparticles (MNPs) into electrospun gelatin nanofibers. When positioned near a rotating magnet (f = 0.5 Hz), the magnetic scaffolds with the embedded MSCs were driven upward/downward in the culture container, which induced mechanical stimulation to MSCs due to spatial confinement and fluid flow. The extracellular matrix-mimicking scaffold and the alternating magnetic field significantly enhanced chondrogenesis instead of osteogenesis. Furthermore, the fiber topography could be tuned with different compositions of the coating layer on MNPs, and the topography had a significant impact on MSC differentiation. Selective up-regulation of chondrogenesis-related genes (COL2A1 and ACAN) was found for the magnetic scaffolds with citric acid-coated MNPs (CAG). In contrast, osteogenesis-related genes (RUNX2 and SPARC) were selectively and significantly up-regulated for the magnetic scaffolds with polyvinylpyrrolidone-coated MNPs. Prior to implantation in vivo, chondrogenic preconditioning of MSCs within the CAG scaffolds under a dynamic magnetic field resulted in superior osteochondral repair. Hence, the magnetic scaffolds together with an in-house rotating magnet device could be a novel platform to initiate multiple stimuli on stem cell differentiation for effective repair of osteochondral defects.
Quantum algorithm for online convex optimization
Authors: He Jianhao , Yang Feidiao , Zhang Jialin , Li Lvzhou
Published: February 2022

We explore whether quantum advantages can be found for the zeroth-order online convex optimization (OCO) problem, which is also known as bandit convex optimization with multi-point feedback. In this setting, given access to zeroth-order oracles (that is, the loss function is accessed as a black box that returns the function value for any queried input), a player attempts to minimize a sequence of adversarially generated convex loss functions. This procedure can be described as a T round iterative game between the player and the adversary. In this paper, we present quantum algorithms for the problem and show for the first time that potential quantum advantages are possible for problems of OCO. Specifically, our contributions are as follows. (i) When the player is allowed to query zeroth-order oracles O(1) times in each round as feedback, we give a quantum algorithm that achieves

O

(

T

)

regret without additional dependence of the dimension n, which outperforms the already known optimal classical algorithm only achieving

O

(

n
T

)

regret. Note that the regret of our quantum algorithm has achieved the lower bound of classical first-order methods. (ii) We show that for strongly convex loss functions, the quantum algorithm can achieve O(log T) regret with O(1) queries as well, which means that the quantum algorithm can achieve the same regret bound as the classical algorithms in the full information setting.
Fragility fractures of the pelvis in the older population
Authors: Sivapathasuntharam Dhanupriya , Smith Gillian , Master Mohammed-Ashraf , Bates Peter
Published: February 2022

Pelvic fractures are an increasingly common injury seen in the older population and represent a significant burden of morbidity and mortality in this age group, as well as a large financial burden on the health service. It is well established that early fixation of femoral neck and acetabular fractures improves outcomes and increases the chances of patients returning close to their premorbid functional baseline. However, fixation of fragility fractures of the pelvis is less well established in current practice. There has been recent development of novel stabilisation techniques for unstable pelvic fractures, designed to tackle the difficulties associated with fixation in poor bone quality, along with medical trials of parathyroid hormone analogue treatment. However, it is still current practice to manage nearly all fragility fractures of the pelvis conservatively. In this article, we consider whether the development of surgical stabilisation techniques for pelvic fragility fractures may have the potential to improve the well-described morbidity and mortality associated with them.
Metabolomic markers of biological fluid in women with reproductive failure: a systematic review of current literatures
Authors: Zhang Yingying , Zhang Tao , Wu Ling , Li Tin Chiu , Wang Chi Chiu , Chung Jacqueline Pui Wah
Published: February 2022

Understanding metabolic changes in reproductive failure, including early miscarriage (EM), recurrent miscarriage (RM), and repeated implantation failure (RIF), may be beneficial to understand the pathophysiology, thus improving pregnancy outcomes. Nine metabolomic profiling studies in women with reproductive failures (4 for EM, 3 for RM, and 2 for RIF) were included for systematic review. In total 78, 75, and 25 significant metabolites were identified and 40, 40, and 34 metabolic pathways were enriched in EM, RM, and RIF, respectively. Among them, 7 and 11 metabolites, and 28 and 28 pathways were shared between EM and RM and between RM and RIF, respectively. Notably, histidine metabolism has the highest impact in EM; phenylalanine, tyrosine, and tryptophan biosynthesis. Ubiquinone and other terpenoid–quinone biosynthesis metabolism have the highest impact factor in RM; alanine, aspartate, and glutamate metabolism have the highest impact factor in RIF. This study not only summarized the common and distinct metabolites and metabolic pathways in different reproductive failures but also summarized limitations of the study designs and methodologies. Hence, further investigations and validations of these metabolites are still urgently needed to understand the underlying metabolic mechanism for the development and treatment of reproductive failures.
19 Plain Film X-Ray Reporting in Orthopaedic Patients: A Reaudit in a District General Hospital
Authors: Khaleeq T. , Shah Foridi J. , Reading J.
Published: February 2022

Aim

To assess clinical evaluation of plain film x-rays requested for patients in the orthopaedic department (clinic and ward)

Standards:

Ionising radiation (medical exposure) regulations irmer 2017 procedure j: recording clinical exposure, national guideline and local guidance is in keeping with irmer and good clinical practice.

Method

50 plain films of randomly selected (using random number generator) who had attended new patient fracture clinic and ward. An initial audit was done in June and an reaudit in September.

The radiology system, clinical notes and clinic letters were reviewed to obtain the relevant data.

Results

Audit: 20 films were documented

30 were not documented

Reaudit

32 films were documented by referring clinician

18 films were not documented by referring clinician

Audit:

Clinical evaluation documented 18

Clinical evaluation not documented 32

Reaudit:

Clinical evaluation documented - 29

Clinical evaluation not documented - 21

Discussion

Whose responsibility? Radiographs commented on in trauma meetings not documented. New radiographs not commented on in clinic.

Limitations - access to more notes from ward.

Conclusions

As outlined in guidance orthopaedic and fracture clinic plain films should be reported by referring clinician or their team. Currently this is being done 64% of the time, significant improvement was seen. This may have medicolegal consequences as it does not follow GMC guidance for good medical practise.

Recommendations

Clinicians to specifically dictate x-ray findings in fracture clinic. Junior staff to take responsibility for documenting x-ray findings as discussed with senior clinicians for trauma patients. Junior staff to review post-op x-rays for all patients and to document.
56 A Quality Improvement Project to Assess and Refine the Handover Process at Morning Trauma Meetings
Authors: Sadiq S. , Tahir M. , Elerian S. , Baker D. , Bruce A. , Nur I. , Malik A.
Published: February 2022

Aim

Poor handover and inadequate transmission of clinical information between shifts can result in patient harm. This study was designed to evaluate the impact of implementing a handover protocol on the quality of information exchanged in the trauma handover meetings in a UK district general hospital.

Method

A prospective single centre observational study was performed at an acute NHS trust, using the define, measure, analyse, improve and control (DMAIC) methodology. Ten consecutive weekday trauma meetings, involving 43 patients, were observed to identify poor practices in handover. This data was used in conjunction with the Royal College of Surgeon’s recommendations for effective handover (2007) to create a standard operating protocol (SOP). Following the implementation of the SOP, a further eight consecutive weekday trauma meetings, involving a further 47 patients, were observed. The data collection was performed by five trained independent observers. The data was analysed using t-test for quantitative variables and chi-square or Fisher’s exact tests for categorical variables.

Results

An improvement in the trauma handover was demonstrated in multiple aspects of handover including patient’s past medical history, injury date, results, diagnosis, consent, mark and starvation status (all p < 0.001). Subgroup analyses showed that handover of neck of femur patients including information on mobility (p = 0.04), Nottingham Hip Fracture Score (p = 0.01), next of kin discussion (p = 0.075) and resuscitation status (p = 0.001) all improved following our interventions.

Conclusions

These results demonstrate that the implementation of a well-structured handover protocol can improve the transmission of critical information in trauma meetings.
109 Enhanced Recovery Program – Impact of ASA Grade on Length of Hospital Stay in Patients Undergoing Hip and Knee Arthroplasties
Authors: Ahmad M. , Chaudhry M.N.
Published: February 2022

Introduction

Total hip and knee arthroplasties are two of the most quality of life enhancing orthopaedic procedures performed. Enhanced recovery (ER) programs have been implemented in orthopaedics surgeries to reduce the physiological and psychological stress of surgery. The American Society of Anaesthesiologists classification system is now the most widely used for measuring physical health status by hip and knee arthroplasty registries worldwide. The aim of the study is to determine whether the ASA score is a predictive of length of hospital stay in patients undergoing hip and knee replacements.

Method

Retrospective data is collected from a consecutive series of 441 charts and Irish National Orthopaedics Register for patients who underwent primary hip & knee replacements from January 1, 2018, to December 31, 2018, in our hospital. All these patients were assigned either ASA Class 2 or 3 in preoperative assessment.

Results

Patients with ASA 2 (319 patients of the total patient for the same period), average length of hospital stay was 4.8 days, whereas for patients with ASA 3 (122 patients of the total), length of hospital stay was 6.5 with mean difference between two groups was 1.7 days (95% confidence interval of this difference).

Conclusions

Patients with ASA 2 stayed shorter in the hospital compared to patients with ASA 3. Therefore, we recommend that pre-operative patients’ optimization to downgrade a patient from an ASA 3 to ASA 2, but prospective analysis would be beneficial to examine the resource implications of such an initiative as well as patient outcomes with longer term follow up.
134 Do Virtual Conferences Provide Similar Educational Benefit to In-Person Conferences?
Authors: McVeigh J. , Williams M.
Published: February 2022

Aim

The “Future of Surgery Report” by RCS England concluded that exposure to technological developments and surgical innovation should take place early in medical education to ensure that future surgeons have the broadest skillset possible. In line with these recommendations, in 2019, we developed a platform for the dissemination of knowledge surrounding surgical innovation: the annual Oxford Surgical Innovation (OxSI) Conference. The 2021 OxSI Conference was hosted virtually due to the impact of the COVID-19 pandemic.

Method

We sought to compare this event with the previous year to identify if there was any difference in the educational benefit between a virtual conference and an in-person conference. Feedback from delegates was collected using a four-point Likert scale.

Results

In 2021, the average scores for the plenary sessions and the workshops were unchanged compared to 2020 (3.6 and 3.5, respectively, p = 0.999). We saw significant differences in our two-outcome metrics, with statistically significant improvement in understanding the practicalities of engaging in safe surgical innovation (Pre 2.70, Post 3.43, +0.73 (P<0.001)) and in awareness of current innovations in surgical practice (Pre 2.77, Post 3.42, +0.65 (P<0.001)).

Conclusions

Our data suggest that the virtual format of the conference provided the same educational benefit as the previous in-person iterations of OxSI whilst reaching delegates all over the world. We plan to conduct future OxSI events using a hybrid model and would recommend other conferences consider the same to allow for continued international attendance in conjunction with the benefits of in-person networking and interaction.
167 Threshold for Intervention in Females with Asymptomatic Abdominal Aortic Aneurysm (AAA)- a Literature Review
Authors: Imad M. , Zarifa M. Abu , Hassona G. , Ayyash I. , El-Nakhal T.
Published: February 2022

Introduction

UK Small Aneurysm Trial, a study conducted in the late 90s, showed that the threshold for asymptomatic abdominal aortic repair in females would be < 5.5 cm. However, this threshold remained debatable. Our aim is to search for the most recent evidence in regard to the AAA repair threshold in females, and factors affecting the decision to intervene.

Method

PRISMA Flow from 2011–2021 was utilized using keywords on PubMed resulted in 913 articles. Upon further review by and full paper, 2 Cohort studies (n = 10102) and 11 narrative and retrospective reviews were found.

Results

2 cohort studies (n = 10102), as well as 2 other studies, showed that the threshold should be 5 cm. There was a split in opinions between another retrospective (n = 4) reviews which argued for a cut-off between < 5 cm and 5.2 cm. The others, showed evidence of better outcomes repairing asymptomatic AAA at a threshold < 5 cm. Meanwhile, 3 studies recommended using ASI diameter < 5.5 cm^2. Overall, the Intervention threshold being 5 cm or less is reasonable for females since they have a 4-fold men risk of rupture rates at 5.5 cm in addition to significant physiologically smaller aortic diameter (1.75 cm) compared with males (2.4 cm).

Conclusions

The threshold for operating on female asymptomatic AAA should be lower than males, with some evidence suggesting < 5 cm compared to 5.5 in men. Patient tailored and risk assessment approach is recommended. Hence, this will be our standard for upcoming clinical audit.
202 VTE Prophylaxis Post-Laparoscopic Cholecystectomy
Authors: Ashcroft K. , Theocharidou L.
Published: February 2022

Introduction

VTE refers to a clot that causes stenosis or blockage of the blood flow in a vein. VTEs are classified as hospital-acquired if they occur within 90 days of hospital admission. Recent hospitalisation and associate immobilisation are well-acknowledged risk factors also included in Well’s score, which is used as part of the diagnostic work up.

NICE guidelines state that patient over 16 years old must be offered VTE prophylaxis either in the form of LMWH or fondaparinux for at least 7 days after an abdominal surgery.

The aim of the audit is to explore whether NICE guidelines regarding the VTE prophylaxis post-laparoscopic cholecystectomy are followed.

Method

The data from all the patients who had laparoscopic cholecystectomy in a two-month period was collected and discharge summaries and TTOs were reviewed to identify whether thromboprophylaxis was prescribed for 7 days following the operation. A second cycle was completed after results of first cycle presented to the surgical team.

Results

Increased in compliance with VTE prophylaxis guidelines observed, although though still suboptimal. 14% of patients received prophylaxis in first cycle, and 34% in the second.

Conclusion

Increased compliance with VTE guidelines observed, however the second cycle only included a small sample of patients which limited reliability. Furthermore, as highlighted by the surgical team, NICE guidelines are vague. There is no clarification regarding types of abdominal operations. No VTE incidences are yet to be identified post-operatively. Medico-legal aspects were also considered.
215 BCC Management in the UK and Overseas. an Audit of a Single Surgeon's Experience
Authors: Abdelaty M. , Ashfaque F.
Published: February 2022

Aim

To compare the management of BCC in a single surgeon’s practice and audit of practice against the British Association of Dermatologist (BAD) recommendations.

To see any differences in terms of management in two different setups and patient population.

Method

Retrospective data collection and statistical analysis comparing the practice in Pakistan between 2011–2014 and recent practice in the NHS at Bradford Teaching Hospitals Foundation Trust from August 2020 to March 2021

Results

53 BCC patients were identified in the UK with a mean age of 71 compared to 64 overseas patients with a mean age of 62. The most common anatomical region for both groups was the face. The histology reports showed a discrepancy to the number of details enlisted. In the overseas group the BCC subtype was not mentioned in 72% of the reports as well as no reporting of clark's level or TNM staging. The mean reporting time was 5 days in the overseas group compared to 8 days in the UK group.

Conclusions

The British Association of Dermatologists has set standards for management of Basal Cell Carcinoma including surgical margins and histological reporting. Areas of improvement have been identified according to those guidelines.
223 Development of Online Surgical Skills Education
Authors: Soleimani-Nouri P. , Komor J. , Das Bibek. , Fadel M. , Ahmad M.
Published: February 2022

Introduction

Online teaching rapidly emerged as a viable alternative to traditional face-to-face education. However, how to teach surgical skills in the online environment has not been established nor evaluated yet.

Method

An international one-day online surgical skills course consisting of lectures, pre-recorded virtual workshops, live demonstrations, and surgical skills teaching in breakout rooms was organised. Simultaneously, a traditional face-to-face surgical skills teaching was held and used as benchmark. Skills development assessed by trained demonstrators and self-reported competency scores were compared between the online and face-to-face event.

Results

In total, 553 participants from 20 different countries attended the online course, 64 were trained in breakout rooms with a 1:5 demonstrator to candidate ratio whilst the remaining candidates participated in didactic skills development sessions. In a separate face-to-face course 20 candidates were trained with traditional methods. Post course competency ratings by demonstrators in suturing, tendon repair and vascular anastomosis were not significantly different between students receiving online breakout room or face-to-face teaching (ps>0.05). The development of the same skills to “articulation” were not different between formats (ps>0.05). Post course self-rated competency scores improved for all technical skills (p<0.001). Small group sessions, both online and face-to-face, received higher satisfaction ratings compared to large group sessions in terms of clarity of instructions, answers to questions and demonstrator feedback.

Conclusions

Online teaching of surgical skills for early training years is an appropriate alternative to face-to-face teaching with the ability to define clear learning objectives, effectively teach surgical skills and achieve similar learning outcomes.
275 Undergraduate Career Aspirations in Northern Ireland - a National Qualitative Study
Authors: Madden S. , Clements J.M. , Martin N. , Kirk S.J.
Published: February 2022

Introduction

Undergraduate career aspirations are accurately translated to chosen career paths. Understanding what influences these decisions has implications for future workforce planning. The aim of this study was to identify future career intentions in Northern Irish Medical Students.

Method

An anonymous voluntary survey consisting of binominal, Likert and free text responses was distributed to all medical students registered at Queen’s University Belfast (QUB). Data was collected over 6 weeks in April-May 2021. The primary outcome was future career aspiration and secondary outcome was the reported attrition rate from medicine. Local Ethical approval was obtained.

Results

202 responses were received (Response rate 15%). Two thirds (n = 135) were female. One third of respondents remained undecided about their future career choice, with senior students demonstrating greatest certainty in future career choice. Respondents were least likely to choose a career in Surgery (33%). Factors influencing these decisions were a lack of academic interest in the speciality, perceived workload, and the length of the training scheme. 10% of respondents were unsure or unlikely to pursue a career in Medicine after they graduated. Thematic analysis demonstrated, fear of making mistakes, poor work life balance and poor working environments as reasons for leaving medicine.

Conclusions

Uncertainty over future career intention remains common with surgery the least popular speciality. The rate of potential attrition is concerning which warrants further investigation.
281 Impact of Using Risk Communication Tools in Counselling Patients with Newly Diagnosed Non-Metastatic Prostate Cancer
Authors: Oxley C. , Thankappannair V. , Saeb-Parsy K. , Lamb B. , Shah N. , Kastner C. , Geoghegan L. , Fox H. , Gnanapragasam V.
Published: February 2022

Introduction

There have been substantial advances in risk communication tools that help patients understand prognosis associated with prostate cancer and the benefit/gain from treatment. Over the last three years, two tools; Cambridge Prognostic Groups (CPG), and Predict Prostate (https://prostate.predict.nhs.uk), along with decision-making consultations with clinical nurse specialists (CNS) have been integrated into the new diagnosis pathway in our unit.

Method

Treatment decisions for patients with new non-metastatic prostate cancer were audited after (2019–2020) and before (2016–2017) new risk communication tools were implemented. Data were compared between the two time periods and also benchmarked against national level data from the National Prostate Cancer Audit (NPCA) (Parry et al 2020; PMID: 32460859). The main outcome measured was comparison of rates of over and under-treatment of disease.

Results

168 and 95 patients were included in the 2019–2020 and 2016–2017 cohorts, respectively. Following implementation there was a reduction in over-treatment (use of radical surgery/radiotherapy) in patients with low risk/CPG1 (23% to 4%). These rates were also better than the national average from NPCA data (4% vs 11%). In parallel, there was an increase in use of radical treatment (reduced under-treatment) in high risk and very high-risk/CPG4-5 disease (84% vs 73%). Again, these rates were also superior to national level data from the NPCA (84% vs 76%).

Conclusions

Incorporating personalised risk-communication tools and dedicated CNS counselling in our unit has reduced over-treatment of early disease and under-treatment of advanced disease. Wider uptake could enhance risk-appropriate treatment of patients with a new prostate cancer diagnosis.