bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechatronic design of a modular artificial honeycomb for the automatic extraction of honey from Apis Melliferas bees in Huancayo, Peru
Authors: Paitan Cardenas Jose A , Povez Nuñez Vrigel K , Zarate Peña Frank W
Published: June 2023

This research develops the mechatronic design of an artificial honeycomb for Apis Melliferas bees, which allows the automatic extraction of honey in the farms of the province of Huancayo, Peru, since Junin produces 208.26 tons of honey annually with traditional and obsolete techniques. This design was executed under the German VDI 2221 standard and contemplates the mechanical, electronic and control system, which are dimensioned according to the theories and laws of: distortion energy, polynomial 3 4 5, involute curve gears, Kirchhoff, Ohm, on-off control, among others. It was possible to design, in Inventor, the honeycomb structure whose cells have a 19° slope for the honey gravity flow, a gear-rack-gear system for the transmission of torque from the servomotor to the cam shaft to move the grid, which opens the flow duct; also, it was possible to design, in Proteus, the electronic system made up by the Arduino UNO, a servomotor of 2. 5 Kg-cm servomotor with rotation restricted to 110° and the 15mm force sensor; finally, the actuator control and the monitoring of the weight according to the on-off logic were programmed in Arduino IDE. According to the simulations performed, the design is technologically feasible.
A Physiological Control for Artificial Heart Pump based on Adaptive Regulation of Heart Rate and the improved BAS Algorithm Optimization
Authors: Liu Xin , Qu Hongyi , Meng Lingwei , Huang Chuangxin , Ma Pengfei , Wang Cong , Wang Qiuliang
Published: June 2023

In order to solve the problem that the traditional artificial heart pump has poor dynamic bionic performance and cannot respond to blood perfusion in real time according to the patient’s state, this paper proposes a new physiological control method based on adaptive adjustment of heart rate. Firstly, a coupled model of the cardiovascular circulatory system and artificial heart pump was established, and the correctness of the model is verified by hemodynamic simulation. Secondly, according to the model-free adaptive control theory, the artificial heart pump physiological control strategy for adaptive regulation of heart rate is designed, including pseudo partial derivative estimation algorithm and adaptive control law. Then, the parameters of the adaptive controller are optimized by the improved beetle antennae search algorithm. Finally, the auxiliary effect and dynamic performance of the adaptive control strategy are studied by numerical methods. The results show that the physiological control method based on adaptive regulation of heart rate realizes the adaptive modulation of heart rate and blood flow, which can meet the needs of blood perfusion in different states and help to promote the recovery of damaged heart.
Key Points Trajectory and Predicted-Real Frames Distinction based Mirror and Glass Detection for Indoor 5G Signal Analysis
Authors: Wang Ziyue , Liu Yanchao , Cheng Xina , Ikenaga Takeshi
Published: June 2023

Mirror and glass are ubiquitous materials that heavily influence the transmission of indoor 5G signals with extremely high frequency. The existing vision system always tends to neglect them or misdiagnose them, which is unsuitable for 5G signal analysis in the 3D indoor environment. This paper proposes key points trajectory distinction and predicted-real frames distinction to detect mirror and glass regions in video sequences. Firstly, key points trajectory is used to extract the special motion information of reflection in mirror and glass region. Secondly, predicted and real frames distinction is used to remove the wrong detection region at the pixel level. Extensive experiments demonstrate that the proposed method achieves 40 - 50 % accuracy higher than another related state-of-the-art method for mirror and glass detection in the general 3D living environment.
Electromagnetic Interference of Unmanned Aerial Vehicle in High Voltage Environment
Authors: Li Xuecheng , Wang Shaolong , Li Haofeng , Zhou Yulong , Guo Haitao
Published: June 2023

The X-ray inspection of wire clamps is used more and more widely. X-ray detection uses UAV (Unmanned Aerial Vehicle) to inspect the clamp with high voltage, which directly contacts the electrified wire clamp. When the strength of the overhead transmission line exceeds the air breakdown strength, extreme discharges will occur, so the control and data transmission performance of the UAV is influenced, and even cause a crash. The electromagnetic interference can also cause the wrong magnetic compass, lead the UAV fails to take off. The UAV and Ray detection systems electromagnetic shielding is analyzed in this article. The simulated online test shows that the electromagnetic protection measures for electrified clamp online X-ray detection with UAV are workable.
Energy Conservation and Loss Reduction Strategy of Active Distribution System with Distributed Photovoltaic Resources Considering Conservation Voltage Reduction
Authors: Lin Qian , Yu Kai , Sun Yandong , Ma Jinliang , Li Mingming , Wang Feifei , Feng Tianyuan
Published: June 2023

With the massive distributed photovoltaic resources and multi-load connected to the distribution network, network loss and energy consumption have become two of the most important issues. To solve this problem, an energy conservation and loss reduction optimization strategy for active distribution network (ADN) considering conservation voltage reduction (CVR) is proposed. First, the probability density distribution of photovoltaic resources output prediction error is fitted by the Gaussian mixture model (GMM) to simulate the random characteristics of distributed photovoltaics. Second, according to the multiple load types, the load controlled by CVR is modeled, cooperating with the on-load tap changer (OLTC) to achieve energy reduction. Finally, the controllable resources are co-optimized to maintain the voltage level while saving energy. Case studies on the modified IEEE-33 node distribution network verify the applicability of the strategy.
Key Factors Affecting the Capacity Value of New Energy and Sensitivity Analysis
Authors: Xu Zhicheng , Xie Feng , Lu Gang
Published: June 2023

The capacity credit (CC) of new energy describes the contribution of new energy to capacity adequacy and power system reliability. Many factors affect the CC of renewable energy systems. It is necessary to study various measures to improve the capacity credit of new energy. In this paper, the CC assessment model of a (photovoltaic) PV power plant based on the effective load carrying capability (ELCC) method is established by the universal generating function method. In addition, the sensitivity analysis of eight different key factors affecting the CC of photovoltaic power plants, such as PV penetration, number of PV output states, PV module failure characteristics, and other eight key factors, is carried out to point out how various factors affect the CC of the new energy. Analyzing the degree and depth of influence of key factors on new energy CC, which can provide reference for new energy CC.
Energy Storage Optimization Method for Flexible Interconnected Low-voltage Distribution Network Based on Positive Semi-definite Programming
Authors: Wang Chenqing , Huang Lulu , Xiong Xiong , Hu Pengcheng
Published: June 2023

With the fast development of the electricity market, the number of small and medium-sized new energy generation in the urban low-voltage distribution networks is increasing. These “retail investors” hope to sell the extra electricity for financial gain. However, these renewable energy generation units have small capacity and obvious intermittent output. Thus, they can not be added to the operation of the power system alone. In this paper, the model is understood from the perspective of optimization theory, and the solution method is given. The optimization problem of the model is given, and the required gradient and Hessian functions are defined. By applying mathematical induction and the properties of the special matrix column, a decomposition formula of the matrix column is derived. Through using this inequality and the standard decomposition of a positive semi-definite matrix, a feasible scheme is formed. The eigenvalue relationship between the sum of elements of a positive semi-definite block matrix and its quasi-diagonal block is given under certain conditions, while the number of such blocks is not required. The standard form of the dual problem is drawn by the method of Lagrange multipliers, and the relationship between the dual solution and the solution of the original problem is studied. The stability of the system is further improved, which provides reference significance for improving the utilization rate of photovoltaic new energy, optimizing the charging and discharging of the energy storage system, and ensuring the safe and reliable operation of the distribution network.
Research on Fuzzy Energy Management Strategy of Hybrid Energy Storage System for Novel Power System
Authors: Huang Cunqiang , An Juan , Liu Qingbiao , Yin Lu , Wang Wei
Published: June 2023

Supercapacitors have great power characteristics and can respond to high-frequency volatility and high-power load of lithium batteries. In a hybrid energy storage system (HESS), the introduction of supercapacitors is an effective scheme to reduce the load pressure and charge/discharge current fluctuation of the battery, which can reflect the high energy density characteristics of lithium batteries and extend the life of lithium batteries. To solve the problem of capacity configuration and energy allocation management of HESS, this paper first researches the dynamic programming model of HESS. Taking the minimum life decay increment of lithium batteries as the optimization objective, the energy distribution scheme of the HESS with the minimum life decay of lithium batteries under different supercapacitor configurations is obtained. Then, according to the decay rate of a unit supercapacitor to the capacity decay increment of lithium batteries, the optimal parameters of supercapacitors are selected, and the fuzzy energy management strategy based on the optimal allocation feature of dynamic programming is proposed. Finally, the simulation results show that compared with the traditional filtering algorithm, the reduction of the lithium battery life attenuation of the proposed scheme is about 2.52 times that of the filtering allocation scheme.
Baseline Load Forecasting for Demand Response Taking Meteorological Factors into Account
Authors: Wang Su , Guo Mingxing , Yu Jing , Jiang Ting , Qian Chen
Published: June 2023

To conduct baseline load forecasting for commercial building users participating in demand response, this paper proposes a demand response baseline load forecasting method that takes meteorological factors into account. Using the principal component analysis, the meteorological indicators contributing more than 80% to the baseline load are selected as the reference data for forecasting neural network baseline load. The isolated forest algorithm and KNN algorithm are used to identify the abnormal data and to fill in the missing data, and the data with different attributes are partially “decoupled.” The two parts of the decoupled data are separately used for neural network load forecasting, and the total baseline load of users is obtained after merging. From these results, it is obvious that the proposed method can effectively improve the forecasting accuracy of the baseline load of the algorithm.
Optimal Dispatch of Integrated Energy System under “Double Carbon” Target
Authors: Wang Zhiwei , Lv Xiangyu , Xiu Ji , Li Dexin , Cheng Qi , Li Meng
Published: June 2023

With the aggravation of environmental problems, countries are more and more aware of the importance of protecting the environment. In 2020, China proposed the goal of “double carbon”. As the main carbon emission industry, the energy industry will become the main battlefield. Therefore, whether the power industry can achieve low-carbon electricity and promote the accommodation of new energy will be the key to achieving carbon neutrality. Under the new background, power grid dispatching should not only consider a single economic benefit, which will lead to a large number of wind and solar curtailments, but also take into account environmental benefits and reduce CO2 emissions. In this paper, an optimal dispatching model of an Integrated Energy System(IES) is established, and CCS is added to CHP units to capture CO2 produced by CHP and send it to P2G. Aiming at the total cost optimization, carbon trading mechanism, wind curtailment cost, and solar curtailment cost are added in the model to ensure the environmental benefits in operation.
Research on Control Strategy of Polar Unmanned Vehicle Wind Power Generation System
Authors: Yu MiaoYuan , Chen Yan , Dou YinKe , Mao QingYang , Qin JinTao
Published: June 2023

Due to the abundant scenery resources in Antarctica, for the unmanned vehicle working in the polar region, the scenery power supply system is built on it, and the control strategies for wind power systems is studied. The max power of the system is tracked by the climbing method, and the variable pitch control ensures that the output power of the generator is near the rated power when the air speed exceeds the rated air speed of the wind turbine. The system is modeled using Matlab/Simulink, and the two control methods are simulated. The simulation results of the system as a whole show that the control strategy can ensure the stable and reliable operation of the system under the environmental conditions of extreme cold and strong wind.
Study on Characteristics of Electromagnetic Interference Caused by Metro Train Movement
Authors: Hu Shangmao , Wu Yongcong , Qian Hai , Liu Gang , Zhang Yi , Yang Feng
Published: June 2023

With the rapid development of the urban power grid and metro system, their mutual influence has become more and more serious. The dc magnetic bias of the transformer caused by the metro becomes the main research direction. In this paper, the characteristics of dynamic electromagnetic coupling between metro trains and transmission lines are studied. First, the motion equation of the metro is written out according to the running law of the train, and three coupling relations are given according to the position of the train. The calculation method of dynamic induced voltage is deduced. Then the influence of parallel length and distance between the metro and transmission line on induced voltage is studied. The dynamic induction voltage increases first and then decreases with the increase of the parallel length of the metro and transmission line and decreases with the increase of the distance between them. It is proposed that the electromagnetic coupling of a single train has limited influence on the dc magnetic bias of transmission lines, but the influence of dynamic electromagnetic coupling cannot be ignored when multiple trains are running simultaneously.
Effect of Space Charge on Stationary and Transient Electric Field Distribution of HVDC Cable Joint
Authors: Zhao Mingwei , Li Dan , Zhang Tuo , Zhu Bin , Ma Tianxiang
Published: June 2023

The conversion of AC XLPE cable lines into direct-current (DC) operation has been proven to be an effective means to improve the transmission capacity of the system. Prefabricated joints are the weakest points of a cable line because of the complex structures, and composite interfaces contained. Therefore, it is of great theoretical and engineering significance to study the field strength distribution of XLPE AC cable prefabricated joints under DC voltage, effectively evaluate their DC tolerance characteristics, and provide a basis for the construction and transformation of XLPE cable DC distribution network system. This paper takes the silicone rubber (SIR), and ethylene-propylene-diene monomer (EPDM) prefabricated joints of 10kV XLPE cables as an example, the cable joint temperature field, and electric field coupling simulation model is established by the finite element analysis software COMSOL Multiphysics. The steady and transient electric field simulation of the joints under different DC voltages and load conditions are carried out considering the influence of space charge. The results show that with the increase of applied voltages and load level, the space charge injection increases, and the maximum steady state field strength in the joint is concentrated at the root of the stress cone, showing an increasing trend. Compared with the SIR joint, the field strength in the EPDM joint is higher. The capacitive component of the field strength in the joint is proportional to the peak value of the impulse voltage under the DC superimposed impulse voltage. In other words, the transient electric field equation meets the superposition principle applied.
Load model and parameter measurement method of DBD for power supply design
Authors: Zhang Xiaowei , Yang Tingxuan , Zhou Jinghua
Published: June 2023

Plasma is widely used in sterilization and disinfection, environmental treatment, and material surface modification. At present, the DBD load equivalent circuit model used in the design of dielectric barrier discharge (DBD) low-temperature plasma generator power supply mainly includes the nonlinear clamping model and linear resistance capacitance model, which have advantages and disadvantages in the research and application of DBD load. This paper focuses on the modeling and parameter acquisition method of the RC parallel DBD load linear model, adds measurement capacitance to the discharge load loop, and obtains RC parallel equivalent model parameters by Q-V and I-V Lissajous-Figure analysis. After the experimental data is processed, the simulation circuit model is built by MATLAB/SIMULINK, and the experimental results are compared with the simulation calculation results. They verify the feasibility of the DBD load parameter measurement scheme and comprehensively demonstrate that the DBD load linear resistance capacitance model has important guiding significance in the design of the DBD power supply.
Life Prediction of Cable Steel Bracket Considering Carbon Steel Corrosion
Authors: Zhang Guilin , Shi Jinghui , Zhang Yujiao , Li Hongsong
Published: June 2023

Replacing the underground cable steel bracket within the service life will increase the maintenance cost, so the life prediction of the cable steel bracket is aroused. The mechanical properties and atmospheric corrosion of carbon steel are the key factors affecting the service life of the bracket. In this paper, a life prediction method of cable steel brackets considering carbon steel corrosion is proposed. First, the mechanical properties of the bracket are analyzed by the finite element model to determine the thickness of the damage. Based on electrochemical corrosion experiments, a life prediction method based on Tafel curve extrapolation is constructed to obtain the corrosion rate; At last, taking the 110 KV underground transmission line of a power grid as an example, the service life of the angle steel bracket of the cable is calculated, which provides a theoretical basis for the selection of steel bracket.
Development of Intelligent Painting System for UAV in Ultra-high Voltage Environment
Authors: Guo Peifeng , Zeng Zhaoqiang , Chen Yangzhuo , Li Zhi , Li Xiaowu , Chen Changlei , She Xi , Zhou Hui
Published: June 2023

Aiming at the problems of high-altitude painting, an intelligent painting unmanned aerial vehicle (UAV) system, including hardware design and software implementation, has been developed. The hardware design of the system mainly includes three parts: drawer-type modular power supply, UAV intelligent painting control system, and high airflow ultra-high-speed motor drive system. The software realization mainly includes two parts: the control thread of the high-voltage main motor and the control thread of the solenoid valve for opening and closing. Besides, the target recognition processing scheme has been designed. To evaluate the accuracy and practicability of this technique, the UAV system has been applied for an intelligent painting experiment in an ultra-high voltage environment, successfully illustrating the feasibility of uninterrupted power supply intelligent painting by UAV.
An IPID Control Method for Aerodynamic Heating Ground Simulation of Hypersonic Vehicles
Authors: Li Jingpeng , KeDeng  , Wang Gang , Zhang Guangming , Bai Zhiqing , Lv Xiaodong
Published: June 2023

In order to accurately predict the thermal environment of hypersonic vehicles, many scholars have devoted themselves to the research related to the aerodynamic heating characteristics of hypersonic vehicles, which provides important solutions for the design of thermal protection systems. An IPID controller is designed for the aerothermal ground simulation system of hypersonic vehicles to complete the target tracking.
Power Analysis Based on Non-intrusive Power Load Monitoring and Decomposition
Authors: Jiang Mingjun , Ren Mingyuan , Wang Xiaolong , Zhang Xiaoling , Lei Caijuan , Wang Haoyun , Jiang Minsuo , Xu Guoyan , He Dong
Published: June 2023

Monitoring power consumption, reducing energy consumption, and achieving healthy and green development are topics of concern. In this paper, a non-invasive power load decomposition method is proposed to monitor power consumption accurately. The innovation of this paper is to propose an optimal solution method of non-invasive power coincidence decomposition and apply this method to the monitoring of power consumption. For the linear superposition estimation of voltage and current data of power equipment, the weight coefficient is calculated by using load decomposition, and the energy consumption proportion of power equipment is obtained. Finally, the experiment proves that this method has the effectiveness of power energy consumption monitoring.
Optimization Design of Voltage Level of Flexible DC Transmission with Offshore Wind Power Based on Genetic Algorithm
Authors: Peng Zhong , Ye Rong , Li Tai
Published: June 2023

Voltage level selection is the foundation of planning and designing for flexible DC transmission with offshore wind power. Traditional voltage level selection method is largely dependent on the manufacturing level of DC cable and converter with having standardization or project experience. For flexible DC transmission with large-scale offshore wind power, the voltage level using the traditional selection method may be not the best. By studying calculation methods of main devices and system cost, under the condition of system capacity and length of DC cable known, system cost function with DC voltage and sub-module capacitor voltage as variables was built. Taking the lowest cost as a target, aiming at the low stability of the optimization results of the traditional genetic algorithm, an optimization design method of DC voltage level based on subsection searching genetic algorithm was proposed. The simulation model of flexible DC transmission with offshore wind power was built based on PSCAD/EMTDC. The AC fault ride-through of the converter station and the safety of the main equipment under the optimal DC voltage level was verified.
Regulation strategy for industrial park considering wind power and electricity price based on the cooperative game model
Authors: Wang Hongzhe , Wang Duo , Yin Hongyan , Cui Jia , Bian Zhenwei , Tian Yanfeng , Wang Zhe
Published: June 2023

With the massive consumption of fossil energy, wind power has become a new energy field. This paper first analyzes the traditional power generation method on the basis of introducing wind power generation into the electricity market. The second is to establish a supply-demand alliance in which thermal power and wind power complement each other, and use information supplementation and other methods to share resources. Therefore, the power generation efficiency of the power grid can be effectively improved. Finally, the simulation example is use to verify the effect of the model on improving the efficiency of wind power consumption, reducing the deviation of the power grid, and increasing the benefits of cooperation alliances.
Research on High Power Fuel Cell DC-DC Based on SiC Devices
Authors: Zheng Ke , Ding Tao , Li Bingyang
Published: June 2023

With the increasing shortage of traditional energy resources, new energy resources such as fuel cells are widely used. However, the front-end output voltage of new energy power generation systems such as fuel cells is low, which cannot directly supply power to the load. Therefore, an efficient DC converter with a high boost ratio is needed to raise the voltage to the required level. The staggered parallel DC boost converter has the characteristics of small input current ripple and high voltage gain, which is very suitable for low voltage and high current input and high voltage output. Compared with Si Mosfet, SiC Mosfet has better on-state and on-switch characteristics. In this paper, the requirements of fuel cells in DC-DC are analyzed, the characteristics and applications of SiC devices are introduced, and the topology and working principle of DC-DC are studied. By comparing the topology of isolated DC-DC and non-isolated DC-DC, the staggered Boost circuit topology is selected. The advantages and working state of multiple staggered parallel circuits are studied in detail.
SOC estimation of lithium battery based on multi-innovation unscented Kalman filter algorithm
Authors: Ji Shiyu , Sun Yi , Chen Zexing , Huang Sheng , Liao Wu
Published: June 2023

Precise of the state is an imperative necessity for ensuring the dependable operation of lithium-ion batteries. The state of charge (SOC) of lithium-ion batteries is arduous to determine precisely. Therefore, a novel method was proposed, which incorporates the Unscented Kalman Filter (UKF) algorithm in combination with the theory of multi-innovation. This method exhibits an enhanced estimation precision of the UKF algorithm by means of re-utilizing prior information. The process encompasses a charge-discharge experiment, and identification of offline parameters for obtaining the RC equivalent-circuit model parameter. The model was verified to be accurate and correct through simulation using Matlab/Simulink. The UKF and MIUKF methods are utilized for estimating the actual operational state of a single lithium battery. According to experimental results, MIUKF offers a higher degree of accuracy and effectiveness in estimating the SOC than the UKF algorithm, with a smaller margin of SOC estimation error.
Early Warning Method of Transformer Core Clamp Disconnection Based on Random Forest Algorithm
Authors: Wang Xiang , Wang Wei , Lv Gang , Deng Wenbin , Tian Jing , Xu Hengshan
Published: June 2023

Transformer core fault is one of the common faults, and core fault monitoring and early warning is an important research topic. An early warning method of transformer core clamp disconnection based on a random forest algorithm is proposed. Firstly, the values of transformer core clamp parameters under different working conditions are measured, and the parameter-state data set is established. Secondly, the features are processed and reduced in dimension, and the parameters with high correlation are selected. Finally, a random forest classification model training parameter-state training set is established to identify the fault of the iron core clamp.
Track reconstruction and analysis of particle interactions in short bent crystals
Authors: Rossi R. , Esposito L.S. , Pesaresi M. , Hall G. , Scandale W.
Published: June 2023

Measurements of the interaction of positively charged particles with bent crystals were
obtained by developing a new and consolidated analysis method, for the use of UA9 collaboration.
The method was deployed to characterize crystals with a length of a few mm along the beam
direction and a bending angle in the order of 10 μrad to 100 μrad, typically
exploited in the CERN accelerators. To assess their properties and quality, the crystals have
been investigated in the Super Proton Synchrotron North Area with a beam of mixed hadrons at
180 GeV. The UA9 telescopic tracker has been used to collect the data. Some
of them are used in the present study to describe and validate the applied data-analysis
methodology.
Intel Stratix 10 FPGA design for track reconstruction for the ATLAS experiment at the HL-LHC
Authors: Camplani A. , Dittmeier S. , Annovi A. , Axiotis K. , Beccherle R. , Biesuz N. , Brenner R. , Débieux S. , Ellert M. , Francavilla P. , Giannetti P. , Kordas K. , Mårtensson M. , Mastrandrea P. , Noulas C. , Oechsle J. , Piendibene M. , Poggi R. , Schöning A. , Sfyrla A. , Sotiropoulou C.L. , Steentoft J. , Tsiakiris T. , Xella S. , Zinßer J.
Published: June 2023

The fast reconstruction of charged particle tracks with high efficiency and track quality is an essential part of the online data selection for the ATLAS experiment at the High Luminosity LHC.
Dedicated custom designed hardware boards and software simulations have been developed to assess the feasibility of a Hardware Tracking Trigger (HTT) system.
The Pattern Recognition Mezzanine (PRM), as part of the HTT system, has been designed to recognize track candidates in silicon detectors with Associative Memory ASICs and to select and reconstruct tracks using linearized algorithms implemented in an Intel Stratix 10 MX FPGA.
The highly parallelized FPGA design makes extensive use of the integrated High-Bandwidth-Memory.

In this paper, the FPGA design for the PRM board is presented. Its functionalities have been verified in both simulations and hardware tests on an Intel Stratix 10 MX development kit.
Smooth local rigidity for hyperbolic toral automorphisms
Authors: Kalinin Boris , Sadovskaya Victoria , Wang Zhenqi
Published: June 2023

We study the regularity of a conjugacy

H
H

between a hyperbolic toral automorphism

A
A

and its smooth perturbation

f
f

. We show that if

H
H

is weakly differentiable then it is

C

1
+
H\"older

C^{1+\text {H\"older}}

and, if

A
A

is also weakly irreducible, then

H
H

is

C
∞

C^\infty

. As a part of the proof, we establish results of independent interest on Hölder continuity of a measurable conjugacy between linear cocycles over a hyperbolic system. As a corollary, we improve regularity of the conjugacy to

C
∞

C^\infty

in prior local rigidity results.
CPC02 Delayed widespread lichenoid drug reaction with radioisotopic response in a patient treated with nivolumab
Authors: Fleming Sarah , Aretz Nicholas Kruseman , Barrett Helen , O’Kane Marina
Published: June 2023

The introduction of immune checkpoint inhibitors for the treatment of a wide variety of malignancies has led to a rise in cutaneous immune-related adverse events (irAEs), including autoimmune and autoinflammatory skin conditions, which typically present within the first 16 weeks of treatment—on average, 3.6 weeks after drug initiation. Cutaneous irAEs occur in approximately 8.7% of patients receiving antiprogrammed cell death type 1 therapy (PD-1). Nivolumab is an antibody against PD-1 widely used for various cancers. As the application of these therapies expands, understanding of their adverse cutaneous effects is essential. We present a 76-year-old woman with metastatic renal cell carcinoma, who developed a widespread pruritic eruption 18 months after commencing nivolumab. Examination revealed a papular and vesicular rash affecting the arms, legs, anterior chest, face, hands and feet. There was a confluent well-demarcated rectangular area of grouped papules on the right side of her back; this site had been treated with radiotherapy for localized rib metastases 1 month prior to onset of rash. There was no mucosal involvement and no systemic symptoms. Three skin biopsies were taken, which showed vacuolar alteration of the basal layer and a band-like inflammatory cell infiltrate at the dermoepidermal junction, with focal areas of subepidermal separation. Direct immunofluorescence was negative, and skin swabs were negative for bacterial and viral infection. A diagnosis of delayed bullous lichenoid drug reaction secondary to nivolumab was made. The area involving the previous radiotherapy field was considered to be a radioisotopic response rather than a radiation recall response as she was already on nivolumab when it occurred. She discontinued nivolumab and commenced oral prednisolone and her skin settled over 5 weeks. Lichenoid dermatitis is a known adverse reaction associated with PD-1 therapy, with improved survival outcomes noted in patients with lichenoid irAEs on PD-1 therapy. Typically, it occurs within 16 weeks, with a documented range of 1–266 days. This patient developed a delayed lichenoid eruption at approximately 550 days, with concurrent radioisotopic response at a previous radiotherapy site. Radiotherapy-induced lichen planus is rare, with only one case report documenting involvement outside the irradiated field. We found no previous reports of nivolumab causing lichenoid drug eruption after such a protracted period. This case adds to the growing literature around PD-1 inhibitor-associated cutaneous eruptions.
P01 Severe adult-onset inflammatory disorder with associated UBA1 somatic mutation
Authors: Vetsiou Evangelia , Smith Steve , Forde Karina , McDonald Sarah , Brian Duncan , Khoo Andre
Published: June 2023

A 70-year-old man was admitted to the hospital with a 2-week history of fatigue, florid erythematous maculopapular rash, elevated inflammatory markers and thrombocytopenia. A skin biopsy was performed that showed features in keeping with Sweet syndrome, which was initially thought to relate to concurrent gastrointestinal sepsis. The patient was commenced on oral prednisolone 30 mg daily. His rash and inflammatory markers improved, but his ferritin levels remained elevated. Within 1 month, he presented again with a widespread rash comprising tender and erythematous nodules. Serial computed tomography did not reveal an underlying malignancy. The patient was referred to haematology for consideration of a bone marrow biopsy, which showed hypercellular marrow with active trilineage haematopoiesis, and dysplastic changes in granulocytes and megakaryocytes. Molecular analysis showed a characteristic UBA1 p.(Met41Leu) mutation, which confirmed a diagnosis of VEXAS syndrome. He was considered for treatment with tocilizumab, but his skin symptoms responded well initially to oral steroids and, later, dapsone. He remains asymptomatic on dapsone. VEXAS syndrome is an autoinflammatory condition, first described in 2020, that results in a constellation of inflammatory and haematological manifestations due to a somatic mutation in UBA1 on the X chromosome. It can affect the skin, cartilaginous structures, lungs, joints and vasculature, as well as the haematopoietic cells. Patients with this condition have only been partially responsive to treatment, with high doses of corticosteroids showing the most consistent benefit of all the modalities tried thus far. The prognosis is poor and diagnosis is usually delayed. To date, relatively little is known about the dermatological manifestations of VEXAS syndrome. These are usually characterized by neutrophilic dermatoses or vasculitis. More recent studies have shown that skin involvement is associated with clonal infiltration of the skin rather than a general proinflammatory activation. This suggests that therapies that target the pathological clone, as well as the proinflammatory milieu, such as steroids and Janus kinase inhibitors, may be useful. However, further studies and trials are required to understand how to best cure the disease.
P07 Not just simple hand eczema: a case of Jo-1-positive antisynthetase syndrome (‘mechanic’s hands’)
Authors: Al-Tameemi Ahmed , Elyoussfi Sarah , El-Naes Raed
Published: June 2023

Antisynthetase syndrome is a rare inflammatory muscle disease related to dermatomyositis and polymyositis. Anti-Jo-1 antibodies are the most detected antibodies in antisynthetase syndrome. The main clinical features of antisynthetase syndrome are myositis, polyarthritis, interstitial lung disease, mechanic’s hands and Raynaud phenomenon. A 50-year-old man with a background of inflammatory muscle disease and interstitial lung disease, for which he is under the care of respiratory and rheumatology teams, was referred to the dermatology department by his general practitioner with refractory xerotic dry fissured skin on his fingers and feet. He reported itchy, sore and painful dry, cracked skin on both his hands, mainly on the fingertips. It did not affect the rest of his body. He trialled potent topical steroids and emollients, but his condition did not improve. He was on a reducing course of prednisolone 15 mg daily and on long-term oxygen therapy at home for interstitial lung disease. On clinical examination, he had an eczematous-looking eruption. The appearance of his hands was in keeping with ‘mechanic’s hands’. Together with the underlying diagnosis of interstitial lung disease, a diagnosis of antisynthetase syndrome was suspected. Blood tests revealed a fibrinogen of 5.39 g L−1 [reference interval (RI) 1.50–4.50], lupus creatine kinase of 1591 IU L−1 (RI 40–320), positive antibodies to Ro (SS-A) and positive antibodies to Jo-1. Jo-1 antibodies are found in dermatomyositis or polymyositis. Ro antibodies are associated with Sjogren syndrome (primary or secondary) or systemic lupus erythematosus, and serum may be antinuclear antibody negative. Therefore, we suspected a diagnosis of antisynthetase syndrome. A patch test showed a positive reaction to nickel, which was deemed to be in keeping with antisynthetase syndrome hand eruption, or ‘mechanic’s hands’. The patient was commenced on mycophenolate, a low dose of acitretin 10 mg and emollients and reported a significant improvement in symptoms. Repeat blood tests were scheduled for 3 months, including lipid profile and liver function test, for monitoring purposes. A follow-up was arranged for 12 weeks. He had a background of recurrent hospital attendance with pericardial effusions and chest symptoms and was tested for COVID-19 multiple times. This case demonstrates the importance of multidisciplinary coordination with rheumatology and respiratory colleagues in antisynthetase syndrome.
P22 Clinicopathologic characteristics of metastatic cutaneous squamous cell carcinoma: a cohort study
Authors: Stefanovic Nicholas , Irvine Alan , Cosgrave Niall , Killion Lisa , Ormond Patrick , Moran Benvon , Barry Rupert
Published: June 2023

Cutaneous squamous cell carcinoma (cSCC) is a keratinocyte tumour with excellent prognosis following early-stage surgical treatment. Nevertheless, cSCC possesses an inherent potential for locoregional and distant metastasis in approximately 4% of cases, contributing to disease-specific mortality. Recent guidance on cSCC management risk stratifies patients based on clinicopathological factors to identify those patients most at risk of metastasis. A retrospective cohort study identified 3455 cSCCs arising in 2522 patients, via review of histopathological diagnoses of cSCC at a tertiary hospital in Dublin, Ireland, between the years of 2009 and 2019. The aim of the study was to describe adequately a large cohort of patients with metastatic cSCC and investigate factors associated with metastasis. Metastatic disease was identified by histopathological and/or radiological confirmation in 116 patients, with complete data available in 105 cases. Twenty-two (21%) were female. Mean age at primary tumour diagnosis was 74.8 years and mean time to first metastasis was 0.8 years. Twenty-six (25%) patients were immunosuppressed, the commonest reason for which was haematological malignancy. Median (SD) size of the primary tumour was 36 (21.65) mm and median depth was 10 (7.43) mm. Eighty-six (82%) tumours were located on the head and neck. Seventeen (16%) of the tumours were recurrent, 58 (55%) were > 20 mm, 38 (36%) demonstrated extension beyond subcutaneous fat, 22 (21%) demonstrated lymphovascular invasion, 24 (23%) demonstrated perineural invasion of nerves > 0.1 mm in diameter and 41 (39%) tumours were poorly differentiated. Twenty-six patients developed distant metastatic disease in addition to nodal metastasis. In most patients in our cohort, AJCC 8th Edition histopathological high-risk cSCC features were absent, apart from size > 20 mm. Conversely, most patients exhibited at least one clinical high-risk cSCC feature as per the British Association of Dermatologists’ guidelines for the management of cutaneous squamous cell carcinoma, including advanced age and tumour location (Keohane SG, Botting J, Budny PG et al. British Association of Dermatologists guidelines for the management of people with cutaneous squamous cell carcinoma 2020. Br J Dermatol 2021; 184:401–14). All patients were discussed at a specialist skin multidisciplinary team meeting, with significant variability noted in preoperative imaging, depending on the primary treating specialty. This cohort illustrates the importance of risk stratification of cSCC on clinicopathological features. This facilitates management decisions and ongoing patient surveillance with a view to preventing disease-specific morbidity and mortality.
P26 Risk factors for complications in cutaneous squamous cell carcinoma and proposal of a simplified follow-up strategy, making use of available healthcare resources
Authors: Micallef Daniel , Dimech Alicia , Pisani David , Camilleri Liberato , Scerri Lawrence
Published: June 2023

Cutaneous squamous cell carcinoma (cSCC) is a common malignancy, generally cured by surgical excision. A minority of such tumours recur, metastasize or even cause death. The 2021 British Association of Dermatologists (BAD) guidelines outline high-risk features that are used to guide the follow-up of patients after a primary cSCC. The aims of this study were to identify histological features of cSCC that are significantly associated with the development of complications, and to compare the sensitivity, specificity and number of appointments required to follow-up patients using different follow-up criteria. In total, 556 cases of primary invasive cSCCs excised between January 2014 and March 2018 were included and followed-up for a minimum of 4 years. Five per cent (n = 26) of tumours were associated with at least one cSCC-related complication, namely, local recurrence 3.8% (n = 21), nodal metastasis 1.6% (n = 9), distant metastasis 0.4% (n = 2) and disease-specific death 0.7% (n = 4). The initial diagnosed complication was local recurrence in 20 of 26 cases. Only two patients had the first complication beyond 2 years of the original cSCC. Factors that were statistically significantly associated with the development of a complication (P < 0.001) are larger diameter, larger depth of invasion, tumour invasion beyond the dermis, perineural invasion (irrespective of size), lymphovascular invasion, gross bone erosion and deep margin < 1 mm. Differentiation and peripheral margin were not significantly associated with complications. Therefore, it may be proposed that patients with tumours with at least one of the following risk factors be followed-up: diameter > 40 mm; depth of invasion > 6 mm; invasion beyond the dermis; presence of perineural or lymphovascular invasion or deep margin < 1 mm. In adopting these criteria, 739 appointments in 156 patients would be required over 2 years (4 monthly during the first year and 6 monthly during the second year). Twenty of the patients who developed a complication would be followed-up (sensitivity 76.9%, specificity 69.4%). Using the BAD guidelines, up to four more patients with complications would have been followed-up (sensitivity 92.3%, specificity 44.7%), but this would have required a total of 1556 follow-up visits in 242 patients. Given the limited resources, patient burden and the fact that local recurrence is most often the first complication, it may be reasonable to offer routine follow-up only to patients who have at least one of the proposed criteria. Coupled with patient education, this strategy could greatly reduce the number of follow-up visits required. Such a strategy may allow resources to be utilized to reduce waiting times, particularly for 2-week wait referrals, decreasing the delay in new skin cancer diagnoses.
P30 Declining staff numbers and increasing workload: is there a solution?
Authors: Wolfe Charlotte , Phillips Rebecca , Laheru Dhruvkumar , Fisher Rachel
Published: June 2023

Within the UK, there is a rapidly rising incidence of malignancies, including cutaneous cancers. Over 1 million new patients are referred to dermatology each year and a large proportion require a diagnostic or therapeutic biopsy. Dermatologists often rely on histopathology to confirm or diagnose cancers, determine margins and perform specialist testing. The increasing rates of cancers are adding significantly to the histopathology workload. According to the Royal College of Pathologists (RCPath), only 3% of departments report having adequate staff to meet clinical demand. There are a significant number of unfilled training posts and a concurrent retirement crisis, with 25% of all pathologists over 55 years old. It can take up to 15 years to train consultants, with the more experienced able to handle greater workloads. The lack of pathologists, with widespread vacancies, has a significant impact. The resulting costs to the health service of employing locums and outsourcing work have been estimated to be £27 million annually. For patients, the costs of these shortages mean delays in diagnosis and treatment. A RCPath key performance indicator advises that 80% of cases should be reported within 7–10 calendar days. Across dermatology departments, there is wide reported variation in reporting times from 1 to 28 weeks. In 2019, the longest wait, on average, was 5.8 weeks. We surveyed 60 histopathology consultants across different National Health Service trusts in England to determine the reasons behind these delays. The survey response rate was 45%. The results showed that 78% of departments have unfilled posts, 83% have employed locum staff or outsourced reporting of skin biopsies in the last 5 years and only 20% are able to meet the RCPath guidance. Additionally, almost one-quarter reported that they have had complaints or serious incidences related to delayed dermatopathology reporting. Survey comments revealed many other areas of potential diagnostic delay from sample labelling and prioritizing to prolonged laboratory processing times, unclear pathways to expedite samples and the lack of histopathology secretaries. This survey highlights the increasing workforce demands and emphasizes the need for innovative changes to avoid delays in patient care. Possible solutions to address increased workload in an understaffed environment include adequate secretarial support, increasing pathology pathway navigators who prioritize urgent cases, improving information technology services, digital slide reporting and developing artificial intelligence to screen samples. Increasing dermatopathology training and exposure to histopathology at a junior level is mandatory. Raising these issues and making them a key investment priority for the government is imperative.