bluuebunny/crossref_metadata_2025 huggingface dataset:
Exploring the effective P-type dopants in two-dimensional Ga2O3 by first-principles calculations
Authors: Zeng H. , Ma C. , Wu M.
Published: May 2024

Exploring effective p-type doping in Ga2O3 is crucial for both fundamental science and emerging applications. Recently, N and Zn elements have been shown to exhibit considerable contributions to effective p-type doping in 3D Ga2O3 experimentally and theoretically, whereas the studies of their doping behaviors in 2D Ga2O3 are rare. In this study, we investigate the possibilities of N and Zn elements to achieve effective p-type doping, manifesting in the introduction of shallow acceptor levels typically less than 0.5 eV in 2D Ga2O3 using first-principles calculations with the generalized gradient approximation + U method. The calculated defect formation energies suggest that the N-doped 2D Ga2O3 structures are more easily formed under Ga-rich conditions, while the Zn-doped structures are more readily generated under O-rich conditions. Moreover, the introduced N and Zn atoms preferentially incorporate on the threefold coordinated OII and pyramidally coordinated GaI sites, accompanying with N3− and Zn2+ oxidation states in 2D Ga2O3, respectively. In particular, the electronic structures indicate that the occupied N-2p and semi-occupied Zn-3d orbitals produce shallow hole levels ranging from 0.09 to 0.33 eV, demonstrating that N and Zn atoms can behave as effective p-type dopants in 2D Ga2O3. The magnetic moments for N- and Zn-doped 2D Ga2O3 are 1.00 μB due to the doping of one hole, where the magnetic moments can be mainly attributed to the N atom and the nearest O atoms, respectively. Our work may offer theoretical guidance for the design of p-type 2D Ga2O3 materials and shed light on its potential optoelectronic and magnetic applications.
When legal interpretation is not about language
Authors: Spaić Bojan , Isibor Roberto
Published: May 2024

Linguistic arguments are paramount in legal interpretation. They are widely used by judges and considered to be
ubiquitous across jurisdictions. It is claimed that they are decisive and limitative in the judicial interpretation of the law.
The claims have long been subject to theoretical scrutiny and, recently, testing within experimental jurisprudence. In this paper,
we analyse the judicial reasoning in a landmark Italian case from the end of the nineteenth century concerning Lidia Poët, an
aspiring practising female lawyer. The case was decided in the last instance by the Turin Court of Cassation. We give a detailed
argumentative analysis of the reasoning of the Court of Cassation in Turin in the Lidia Poët case and show that the crucial
linguistic and systematic arguments used are not grounds for the interpretative decision to exclude women from the denotation of
the word “lawyer.” We conclude that the linguistic arguments employed by courts often do not do the argumentative work they are
expected to do. Instead, they cover the substantial views that have determined the ascription of normative meaning to a term or
sentence.
Tone sandhi in Nuosu Yi at the interface
Authors: Lee Seunghun J. , Shen Hong
Published: May 2024

Nuosu Yi, a Tibeto-Burman language, has a tone sandhi pattern, where a lexical [33] -tone is realized
as [44]-tone on the surface. This tone sandhi pattern in Nuosu Yi is described as having a “weak phonological status
(Gerner, 2013: 28)”. In this study, we confirm this observation and further show
the role of phonological length in the tone sandhi patterns. A closer examination of the sandhi contexts, however, reveals an
intricate interplay between phonology and morphology of various aspects of Nuosu Yi grammar. Tone sandhi is conditioned by word
size and morphological processes. Monosyllabic words, but not multi-syllabic words, tend to undergo tone sandhi, and tone sandhi
is sensitive to morphological operations such as compounding.
Emergence of differential object marking in Asia Minor Greek
Authors: Atlamaz Ümit , Bagriacik Metin
Published: May 2024

This paper investigates the emergence of differential object marking (DOM) in the Asia Minor Greek dialect of
Pharasa (PhG) under contact with Turkish. We show that DOM in Turkish and PhG are both instances of structural accusative case and
DOM can be formally modeled as context sensitive dependent case. We propose that two factors caused the emergence of DOM in PhG,
namely (i) case neutralization in indefinite contexts, and (ii) an increase in the number of V-NP idioms borrowed from Turkish
where the NP is in bare form. These perturbations led to a significant change in the overall data created by the community
resulting in mixed input for the younger generations. Once the amount of bare NPs passed a certain threshold, a divergent grammar
became inevitable. We test our proposal using an abductive generalization learning algorithm based on the Tolerance Principle and
running a number of simulations. Our simulation results confirm our hypothesis.
Stable GDP-tubulin islands rescue dynamic microtubules
Authors: Bagdadi Nassiba , Wu Juliette , Delaroche Julie , Serre Laurence , Delphin Christian , De Andrade Manon , Carcel Marion , Nawabi Homaira , Pinson Benoît , Vérin Claire , Couté Yohann , Gory-Fauré Sylvie , Andrieux Annie , Stoppin-Mellet Virginie , Arnal Isabelle
Published: May 2024

Microtubules are dynamic polymers that interconvert between phases of growth and shrinkage, yet they provide structural stability to cells. Growth involves hydrolysis of GTP-tubulin to GDP-tubulin, which releases energy that is stored within the microtubule lattice and destabilizes it; a GTP cap at microtubule ends is thought to prevent GDP subunits from rapidly dissociating and causing catastrophe. Here, using in vitro reconstitution assays, we show that GDP-tubulin, usually considered inactive, can itself assemble into microtubules, preferentially at the minus end, and promote persistent growth. GDP-tubulin-assembled microtubules are highly stable, displaying no detectable spontaneous shrinkage. Strikingly, islands of GDP-tubulin within dynamic microtubules stop shrinkage events and promote rescues. Microtubules thus possess an intrinsic capacity for stability, independent of accessory proteins. This finding provides novel mechanisms to explain microtubule dynamics.
Neural Audio Coding with Deep Complex Networks
Authors: Ru Jiawei , Wang Lizhong , Jia Maoshen , Wen Liang , Wang Chunxi , Zhao Yuhao , Wang Jing
Published: May 2024

This paper proposes a transform domain audio coding method based on deep complex networks. In the proposed codec, the time-frequency spectrum of the audio signal is fed to the encoder which consists of complex convolutional blocks and a frequency-temporal modeling module to obtain the extracted features which are then quantized with a target bitrate by the vector quantizer. The structure of the decoder which reconstruct the time-frequency spectrum of the audio from quantized features is symmetrical to the encoder. In this paper, a structure combining the complex multi-head self-attention module and the complex long short-term memory is proposed to capture both frequency and temporal dependencies. Subjective and objective evaluation tests show the advantage of the proposed method.
An Improved P-wave Peak Location Method Based on Pan-Tompkins Algorithm
Authors: Liu Runjie , Ma Chaoqi , Zhang Qionggui , Gao Xu , Zhang Lianji
Published: May 2024

Electrocardiogram (ECG) signal can reflect the health of the heart, and P wave is an important part of ECG signal, which reflects the excitatory conduction process of the heart. By precisely locating the P waves in the ECG signal, important information about heart disease can be obtained. In this paper, a method of P-wave peak localization based on Pan-Tompkins algorithm is proposed. Firstly, the ECG signal is decomposed by wavelet transform, and the coefficients of each layer are processed to filter out the noise such as baseline drift and electromyographic interference in the ECG signal. After the location of R wave in the signal was found by the Pan-Tompkins algorithm, the QRS wave was eliminated, and then the possible P wave location was found by the improved Pan-Tompkins algorithm. Finally, the correct P wave was screened by a screening strategy. Experimental results show that the sensitivity and accuracy of the P-wave localization algorithm proposed in this paper reach 94.78% and 95.10%, respectively. It shows that the proposed algorithm has good performance for P-wave localization.
Distilling Structural Knowledge for Platform-Aware Semantic Segmentation
Authors: Li Guilin , Wang Qiang , Zheng Xiawu
Published: May 2024

Knowledge Distillation (KD) aims to distill the dark knowledge of a high-powered teacher network into a student network, which can improve the capacity of student network and has been successfully applied to semantic segmentation. However, the standard knowledge distillation approaches merely represent the supervisory signal of teacher network as the dark knowledge, while ignoring the impact of network architecture during distillation. In this paper, we found that the student network with a more similar architecture against the teacher network obtains more performance gain from distillation. Therefore, a more generalized paradigm for knowledge distillation is to distill both the soft-label and the structure of the teacher network. We propose a novel Structural Distillation (SD) method which introduces the structural similarity constraints into vanilla knowledge distillation. We leverage Neural Architecture Search technique to search optimal student structure for semantic segmentation from a well-designed search space, which mimics the given teacher both in terms of soft-label and network structure. Experiment results make clear that our proposed method outperforms both the NAS with conventional Knowledge Distillation and human-designed methods, and achieves sota performance on the Cityscapes dataset under various platform-aware latency constraints. Furthermore, the best architecture discovered on Cityscapes also transfers well to the PASCAL VOC2012 dataset.
The influence of ripple on DC energy measurement and the improvement of wavelet threshold function filtering method
Authors: Bai Jingfen , Meng Jing , Yang Yubo , He Yunlong
Published: May 2024

DC energy has been applied in the construction of DC power grids, photovoltaic power generation, energy storage, and rapid charging of electric vehicles. The application of DC energy is of great significance for energy conservation, emission reduction, carbon reduction, and efficiency increase. In this paper, the reasons for the decrease in DC energy measurement accuracy caused by ripples in voltage and current are analyzed. The minimum requirements of ripples for DC energy meters are analyzed, and the traditional filtering method based on wavelet threshold is studied. An optimized and fast iterative wavelet threshold function was designed, the current signal of electric vehicle charging was selected, and the effectiveness of the algorithm proposed in this paper was verified through simulation.
Chaos control of Superbuck converter based on resonant parametric perturbation method
Authors: Gao Hongzhi , Han Guangyuan , Zhang Ran , Liu Yi , Wang Lihua
Published: May 2024

As a current control method, valley current mode (VCM) control is widely applied in DC-DC converters due to its absence of dead time restrictions and excellent transient response performance. This paper constructs a discrete iterative model of the VCM-controlled Superbuck converter. The bifurcation diagram is employed to analyze the impact of the reference current variation on the converter, and further validation is conducted through phase portraits and Poincaré sections. By introducing the resonant parametric perturbation method, a small perturbation signal is applied to the reference current to achieve chaos control. Simulation results demonstrate that this method effectively suppresses the chaotic behaviour of the Superbuck converter with the variation of reference current, significantly improving the performance and output ripple of the converter.
A novel pose calibration method for laser displacement sensor in the five-axis on-machine measurement system
Authors: Wang Dongfang , Huang Xiaoshuai , Xu Wei , Li Wenlong
Published: May 2024

The five-axis on-machine measurement system, equipped with a laser displacement sensor, offers an effective approach for conducting on-site inspections of freeform surface parts. It is crucial to address the calibration error pertaining to the sensor’s pose, encompassing both the beam direction and the zero position, as it directly impacts the measurement accuracy. This paper presents a new approach for the calibration of a laser displacement sensor’s pose, which is mounted on the spindle of a five-axis gantry machine tool. The proposed method utilizes measurements taken from multiple angles of a standard ball. Through the utilization of spherical constraints and coordinate translation transformation, the Levenberg-Marquardt iteration method is employed to derive the sensor’s beam direction, while the least square method is used to determine the sensor’s zero position. Applying this proposed method, the maximum error in the distance between the centers of the standard double ball is below 0.008 mm, which can meet the precision requirements of on-site inspection of freeform surface parts.
Simulation study on hydraulic lifting mechanism of lift-sliding mechanical parking system
Authors: Gong Wen
Published: May 2024

A mechanical parking system is an important parking equipment that can improve the utilization rate of urban space. In China, the lift-sliding mechanical parking system is the most widely used. Among many types of drives, the hydraulic pump-hydraulic cylinder type has advantages such as convenient system integration and expansion, energy saving, etc. The system is prone to vibration and pressure shock during operation. This paper focuses on the causes of vibration and hydraulic impact, constructs a simulation model, and analyzes the causes of vibration and hydraulic impact through simulation results, guiding equipment optimization.
Phase external calibration in interferometric microwave radiometer
Authors: Li Xin , Li Hao , Li Pengfei
Published: May 2024

The receiver error of the interferometric microwave radiometer can be calibrated by injecting the correlated noise into the receiver’s calibration port. However, in the antenna part without the internal calibration link, the residual phase error can be calibrated by an external noise source in an anechoic chamber and the significance of phase external calibration [1][2] is also verified by imaging the anechoic chamber.
Real-time Finite Element Analysis based on surrogate model
Authors: Xie Xiaoxuan , Ma Liping , Zhang Qingmeng , Zhang Jianyong , Dong Wendi , Chen Rumeng
Published: May 2024

In the field of engineering, Finite Element Analysis (FEA) serves as a pivotal numerical simulation tool. Nevertheless, its inherent offline nature and dependency on real-time data pose limitations on its versatility. To confront this challenge, a real-time FEA approach centered on surrogate modeling has been developed. This method enables the instantaneous prediction of critical performance parameters, thereby providing crucial support for real-time decision-making and process monitoring. In the context of this study, the focus is on the glass compression molding process, a process that is not easily observable. The research commences with preliminary thermal conduction simulations conducted using ABAQUS software. Subsequently, a surrogate model is constructed to facilitate real-time FEA for the temperature field of the glass preform. Finally, Unity 3D software is harnessed for visualization, offering an effective tool for the real-time monitoring and control of the glass-forming process.
Adversarial sample detection for EEG-based brain-computer interfaces
Authors: Zhang Hao , Gu Zhenghui
Published: May 2024

Deep neural networks (DNNs) play a pivotal role within the domain of brain-computer interfaces (BCIs). Nevertheless, DNNs are demonstrated to exhibit susceptibility to adversarial attacks. In BCIs, researchers have been concerned about the security of DNNs and have devised various adversarial defense methods to resist adversarial attacks. However, most defense methods encounter performance degradation when dealing with normal samples due to changes in the original model. As an alternative strategy, adversarial detection aims to devise additional modules or use statistical properties to identify potentially adversarial samples without changing the original model. Hence, the present study provides a comprehensive evaluation of several typical adversarial detection methods applied to EEG datasets. The experiments indicate that the detection method based on the kernel density estimation (KDE) shows the best performance under various adversarial attacks.
Passive imaging in composite plates using Green’s function reconstruction from the diffuse field
Authors: Wang Chao , Li Haicheng , Zhu Qi , Wu Chenchen , Su Zhan
Published: May 2024

Aiming at the problem that enables damage detection in real-time without any active excitation sources, we propose a new passive detection way based on diffuse field for structural health monitoring of CFRP structures. In this work, the wave propagation was first simulated with a k-space pseudo-spectra method in CFRPs. A diffuse field can be generated after multiple scattering from fibers and boundary reflections. After that, the reconstruction of Green’s function was investigated through different parameters including the number of noise sources, pulse bandwidth, transducer distance, etc. The delamination inspection process was explored by contrasting the reconstructed Green’s function with the referenced Green’s function on the composite plate. Finally, a probability distribution-based imaging algorithm was further applied for delamination imaging.
Total Plate Count of Traditionally Produced Smoked Skipjack in Ambon
Authors: Marthina Tapotubun Alfonsina , Rieuwpassa Fredrik , Matrutty Theodora E.A.A. , Nanlohy Hellen , Apituley Yolanda M.T.N
Published: May 2024

In Ambon City, smoked skipjack is very popular and is one of the people’s daily sources of protein. Smoked skipjack is classified as a ready-to-eat food ingredient. As a ready-to-eat product, the food safety aspect of smoked skipjack is a scientific fact that must be identified and disclosed so that people can consume it safely. The aim of this research was to determine the safety of smoked skipjack products produced in three production center villages in Ambon City based on the total plate count (TPC) value. The research applied exploratory method and was carried out in two stages: 1) conducting observations at six smoked skipjack home industries in three villages; 2) performing an analysis of the total plate count (TPC) of the smoked skipjack. The TPC analysis was carried out in the Fisheries Products Technology laboratory at Pattimura University. The total plate count (TPC) of smoked skipjack from three home industries in Ambon City is at a safe level for consumption, namely from TPC 3,8 x 102 CFU g−1 to 1,4 x 104 CFU g−1. Smoking is done traditionally with the same facilities and processes except for the form of smoked fish and the way it is displayed when sold.
Growth and addition in a herding model with fractional orders of derivatives
Authors: Yap Yee Jiun , bin Segi Rahmat Mohamad Rafi , Hui Pak Ming
Published: May 2024

This work involves an investigation of the mechanics of the herding behavior using a non-linear timescale, with the aim to generalize the herding model which helps to explain frequently occurring complex behavior in the real world, such as the financial markets. A herding model with fractional orders of derivatives was developed. This model involves the use of derivatives of order α where

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Perceptual Learning
Authors: Doyon Maxime
Published: May 2024

Over a lifetime, our perceptual capacities undergo transformations that impact our ability to recognize and process complex perceptual information. The result is ‘perceptual plasticity’, the ability to adapt and reorganize one’s sensory processing mechanisms and perceptual abilities in response to changes in sensory input, experiences, or dispositions. Progress in our understanding of perceptual plasticity’s first-personal manifestations is made by drawing insights from the phenomenological repertoire. This chapter makes this case by drawing attention to one specific class of phenomena—perceptual learning, viz. long-lasting perceptual change that results from practice or experience—and shows how phenomenology can contribute to the discussion over its nature and scope. It begins by analysing Husserl’s genetic phenomenology and shows how perceptions are informed by the weight of our experiential history. Starting from Merleau-Ponty, the chapter then analyses the body-schematic changes perceivers undergo when they develop perceptual skills and habits in response to changing situations and conditions.
Seasonality drives leaf solute potential independently from drought in grapevines. A commentary on ‘Grape cultivars adapted to hotter, drier growing regions exhibit greater photosynthesis in hot conditions despite less drought-resistant leaves’
Authors: Carlos Herrera Jose , Hochberg Uri
Published: May 2024

This article comments on:

Gabriela Sinclair, Erin R. Galarneau, Josh F. Hnizdor, Andrew J. McElrone, Michael Andrew Walker and Megan K. Bartlett, Grape cultivars adapted to hotter, drier growing regions exhibit greater photosynthesis in hot conditions despite less drought-resistant leaves, Annals of Botany, Volume 134, Issue 2, 1 August 2024, Pages 205–217 https://doi.org/10.1093/aob/mcae032
PQSDC: a parallel lossless compressor for quality scores data via sequences partition and run-length prediction mapping
Authors: Sun Hui , Zheng Yingfeng , Xie Haonan , Ma Huidong , Zhong Cheng , Yan Meng , Liu Xiaoguang , Wang Gang
Published: May 2024

Motivation

The quality scores data (QSD) account for 70% in compressed FastQ files obtained from the short and long reads sequencing technologies. Designing effective compressors for QSD that counterbalance compression ratio, time cost, and memory consumption is essential in scenarios such as large-scale genomics data sharing and long-term data backup. This study presents a novel parallel lossless QSD-dedicated compression algorithm named PQSDC, which fulfills the above requirements well. PQSDC is based on two core components: a parallel sequences-partition model designed to reduce peak memory consumption and time cost during compression and decompression processes, as well as a parallel four-level run-length prediction mapping model to enhance compression ratio. Besides, the PQSDC algorithm is also designed to be highly concurrent using multicore CPU clusters.

Results

We evaluate PQSDC and four state-of-the-art compression algorithms on 27 real-world datasets, including 61.857 billion QSD characters and 632.908 million QSD sequences. (1) For short reads, compared to baselines, the maximum improvement of PQSDC reaches 7.06% in average compression ratio, and 8.01% in weighted average compression ratio. During compression and decompression, the maximum total time savings of PQSDC are 79.96% and 84.56%, respectively; the maximum average memory savings are 68.34% and 77.63%, respectively. (2) For long reads, the maximum improvement of PQSDC reaches 12.51% and 13.42% in average and weighted average compression ratio, respectively. The maximum total time savings during compression and decompression are 53.51% and 72.53%, respectively; the maximum average memory savings are 19.44% and 17.42%, respectively. (3) Furthermore, PQSDC ranks second in compression robustness among the tested algorithms, indicating that it is less affected by the probability distribution of the QSD collections. Overall, our work provides a promising solution for QSD parallel compression, which balances storage cost, time consumption, and memory occupation primely.

Availability and implementation

The proposed PQSDC compressor can be downloaded from https://github.com/fahaihi/PQSDC.
Meaning and prediction of ‘excess mortality’: a comparison of Covid-19 and pre-Covid-19 mortality data in 31 Eurostat countries from 1965 to 2021
Authors: Gill Bernhard , Kehler Theresa , Schneider Michael
Published: May 2024

Determining ‘excess mortality’ makes it possible to compare the burden of disasters between countries and over time, and thus also to evaluate the success of mitigation measures. However, the debate on coronavirus disease 2019 (Covid-19) has exposed that calculations of excess mortalities vary considerably depending on the method and its specification. Moreover, it is often unclear what exactly is meant by ‘excess mortality’. We define excess mortality as the excess over the number of deaths that would have been expected counter-factually, that is without the catastrophic event in question. Based on this definition, we use a very parsimonious calculation method, namely the linear extrapolation of death figures from previous years to determine the excess mortality during the Covid-19 pandemic. But unlike most other literature on this topic, we first evaluated and optimized the specification of our method using a larger historical data set in order to identify and minimize estimation errors and biases. The result shows that excess mortality rates in the literature are often inflated. Moreover, they would have exhibited considerable excess mortalities in the period before Covid-19, if this value had already been of public interest at that time. Three conclusions can be drawn from this study and its findings: (i) All calculation methods for current figures should first be evaluated against past figures. (ii) To avoid alarm fatigue, thresholds should be introduced which would differentiate between ‘usual fluctuations’ and ‘remarkable excess’. (iii) Statistical offices could provide more realistic estimates.
O05 Single-cell transcriptomic signature of paradoxical eczema in patients with psoriasis treated with biologics
Authors: Al-Janabi Ali , Martin Paul , Simpson Catherine , Rhys Hefin , Khan Adnan , Eyre Steve , Christofi Maria , Foulkes Amy , Skelton Andrew , Viatte Sebastien , Barton Anne , Morris Andrew , Smith Catherine , Griffiths Christopher , Warren Richard
Published: May 2024

Introduction and aims

Biologics targeting the tumour necrosis factor (TNF) and the interleukin (IL)-17/23 axis are highly effective treatments for psoriasis but can result in cutaneous adverse events. The pathogenesis of paradoxical eczema, an atopic dermatitis (AD) phenotype occurring after biologic initiation in people with psoriasis, is unknown. This study explored the systemic disease signature of paradoxical eczema.

Methods

We used single-cell RNA-Seq on peripheral blood mononuclear cells (PBMCs) from three patients with psoriasis with paradoxical eczema, and three matched, biologic-treated controls who had psoriasis. Differential gene expression, gene network expression and cell–cell interaction (using MultiNicheNet) analyses allowed comparison of cases and controls. We assessed overlap between paradoxical eczema and AD using six AD transcriptome datasets.

Results

Overall, 32 827 PBMCs (14 521 from cases, 18 306 from controls) were included and categorized into 27 clusters. Between cases and controls, there were 727 differentially expressed genes (DEGs) (log fold-change > 0.25, adjusted P < 0.05). A total of 94 of the top 100 DEGs were from monocytes. Significant DEG networks (P < 0.05) mostly mapped to T-cell and monocyte clusters, with commonly enriched pathways in cases including interferon (IFN)-γ, IFN-α, TNF, IL-2/signal transducer and activator of transcription 5 and T-cell differentiation pathways. Cell–cell interaction analysis revealed that the most prioritized interactions in controls, based on differential expression data and known ligand-receptor interactions, included immune regulatory interactions (including ligands such as transforming growth factor β1 and lymphocyte-activation gene 3). In cases, functions of prioritized interactions included chemotaxis, leucocyte activation, T-cell priming and IFN-γ signalling. There was significant enrichment of concordance in the direction of effect of DEGs (65%, P = 5.39 × 10−6) and enriched pathways (85%, P = 3.62 × 10−13) between AD and paradoxical eczema.

Conclusions

Patients with paradoxical eczema have reduced immune regulatory mechanisms and evidence of monocyte and T-cell activation systemically, with increased production IFN-γ, IFN-α and TNF. There is a significant overlap with the AD transcriptome.
O06 Naïve human keratinocytes initiate a chromatin-protective mechanism in response to ultraviolet radiation through the upregulation of histone deacetylase 5
Authors: Tsai Yu-Hsuan , Watson Rachel , Langton Abigail
Published: May 2024

Introduction and aims

During normal development and throughout life, epigenetic changes arise in response to an individuals’ behaviour and environmental exposures. Histone deacetylases (HDACs) are chromatin-modifying enzymes that regulate gene expression and their activity and expression in primary human keratinocytes alters with increasing age. Solar ultraviolet radiation (UVR) is a major causative factor of skin ageing, but how this factor affects HDAC expression and activity is largely unknown. We aimed to determine how UVR exposure affects HDAC expression and activity in primary human keratinocytes.

Methods

Normal human epidermal keratinocytes (NHEKs) from juvenile (aged 1–6 years; n = 3), middle-aged (56–61 years; n = 3) and aged (83–85 years; n = 3) donors were exposed to solar-simulated radiation (SSR) and HDAC abundance and activity were assayed.

Results

Exposure to SSR significantly increased HDAC activity in primary NHEKs irrespective of donor age (P < 0.05). However, Western blotting for HDAC abundance revealed that there was a differential response to SSR exposure across age groups; juvenile NHEKs expressed significantly more HDAC5 in response to SSR (P < 0.05) than cells from middle-aged or aged donors. Furthermore, following SSR exposure of juvenile NHEKs, the cellular localization of HDAC5 was redistributed to the nucleus from the cytoplasm. Dual immunofluorescence staining revealed that those NHEKs with nuclear HDAC5 expression were also positive for p16INK4a, a robust marker of cellular senescence (P < 0.01).

Conclusions

Our Results suggest that naïve human keratinocytes are responsive to UVR exposure and appear to initiate a chromatin-protective mechanism through the upregulation of HDAC5 to prevent gene expression of damaged DNA.
O08 Exploring the effect of skin ageing-related basement membrane collagen loss on nuclear mechanics
Authors: Summan Simranpreet , Mayes Andrew , Gunn David , Madapura Pradeepa , Gautrot Julien , Caley Matthew , O’Toole Edel
Published: May 2024

Introduction and aims

Skin ageing is a universal process that can increase susceptibility to inflammation and disease. Basement membrane collagens (BMCs) are reduced during ageing and the consequences are poorly understood. BMC sensing of mechanical stress, vital for skin homeostasis, elicits signalling sensed via cytoskeletal actin filaments to the linker of nucleoskeleton and cytoskeleton (LINC) complex (composed of nesprin and sun proteins), nuclear lamina and lamina-associated chromatin. Our hypothesis is that BMC loss during ageing leads to a deformation of the nucleocytoskeleton and disrupts chromatin organization in keratinocytes, leading to impairment of epidermal differentiation and inability to withstand mechanical stress.

Methods

To explore the role of BMC in mechanical stress response, stable lentiviral short hairpin (sh)RNA knockdowns of Col7 (shCol7) and Col17 (shCol17) were generated in immortalized N/TERT keratinocytes. Western blot (WB) validated knockdowns were compared with shC nontargeting control. IncuCyte assays showed shCol17 had a hyperproliferative phenotype compared with shC. Sun2 was reduced in shCol17 (P < 0.001) compared with shC (n = 5 experimental replicates). The mechanical stretch effect on cells on a flexible membrane was studied using immunofluorescence and WB analysis. Images taken from the IN Cell Analyzer confocal microscope were analysed to detect changes in protein expression and localization. Nuclear and cytoplasmic fractions made before and after stretch were analysed by WB.

Results

We observed collagen-specific responses to stretch-induced stress with changes to actin, components of the nuclear membrane, and LINC complex proteins. Additionally, work on investigating chromatin changes with BMC knockdown using Cleavage Under Targets & Tagmentation and Cleavage Under Targeted Accessible Chromatin assays is ongoing.

Conclusions

Our data show an altered nucleocytoskeleton in the context of BMC loss and mechanotransduction in skin. These data could provide novel insights into epidermal regulation by BMC in ageing.
O13 Benchmarking a human pluripotent stem cell-derived hair-bearing skin organoid model to prenatal skin
Authors: Gambardella Laure , Torabi Feri , Foster April , Admane Chloe , Winheim Elena , Gopee Nusayhah Hudaa , Olabi Bayanne , Rowe Vicky , Sumanaweera Dinithi , Le Phuong Ahn , Serdy Sara , Kim Jin , Deakin CiCi , Lee Jiyoon , Stephenson Emily , Botting Rachel , Koehler Karl , Teichmann Sarah , Haniffa Muzlifah
Published: May 2024

Introduction and aims

Molecular regulation of mammalian skin development has been largely derived from murine studies. The lack of human studies stems primarily from the difficulties in prenatal human skin access. There is an important need to study human prenatal skin owing to the notable differences between human and mouse skin and the paucity of mechanistic understanding of congenital skin disorders.

Methods

We assembled the first comprehensive multiomic reference atlas of prenatal human skin (21 samples from 7 to 16 postconception weeks), combining single-cell (235 201 cells) and spatial transcriptomic data. We followed 84 skin organoids (SkOs) using single-cell analysis over a 5-month culture period and characterized the spatial organization of the skin in mature SkOs. Prenatal skin, SkO and any relevant pre-existing single-cell RNA-Seq datasets were integrated into the analysis. Cell–cell interactions and cell-lineage determination were explored using CellPhoneDB and trajectory inferences. We evaluated the differentiation trajectory alignment between prenatal skin and SkO using the Genes2Genes analysis.

Results

Our findings reveal predicted factors regulating the epithelial–mesenchymal crosstalk during human hair follicle formation; progressive expression of scar-promoting genes in later gestation, potentially contributing to scarless healing properties of human prenatal skin observed during the early stages of gestation and expression of genes causing genetic skin disorders in the same cell types in prenatal human skin and SkO. We also found that SkOs morphologically recapitulate human skin development from early (periderm formation and shedding) to late (cornification and hair follicle formation) stages. We also demonstrated that SkO and prenatal skin mesenchyme differentiation into hair follicle dermal condensate and dermal papilla is highly conserved at the cellular and molecular level.

Conclusions

SkOs faithfully recapitulate human prenatal skin development and are a valuable model for mechanistic studies on skin development including hair follicle biology and congenital skin disorders.
O18 Precision genome editing for targeted correction of pathogenic D50N mutation in keratitis–ichthyosis–deafness syndrome using CRISPR/Cas9 and homology-directed repair
Authors: Gobalakrishnan Krishshan , Jayarajan Vignesh , Kinsler Veronica , Di Wei-Li
Published: May 2024

Introduction and aims

Keratitis–ichthyosis–deafness (KID) syndrome is an ectodermal disorder that causes blindness, skin inflammation and deafness. It is caused by autosomal dominant mutations in the gap junction beta 2 (GJB2) gene with 86% being a hotspot mutation on c.148G>A, resulting in the amino acid replacement (D50N) in its coding protein connexin 26 (Cx26). There is currently no curative treatment for KID syndrome. We aim to correct the hotspot mutation D50N using a genome-editing approach.

Methods

Keratinocytes generated from the patient with KID who had a D50N mutation (KID-KCs) were genetically corrected by homologous-directed repair/CRISPR-Cas9 using an electroporation approach. The correction efficiency was determined and analysed using Sanger sequencing and Synthego Inference of CRISPR Edits analysis. The off-target effects were confirmed by whole-exome sequencing [exome next-generation sequencing (NGS)]. Furthermore, the functional recovery following genome editing was assessed by GJB2 mRNA production, Cx26 protein expression, and trafficking and hemichannel activity.

Results

The correction efficiencies ranged from 95% to 100% with different doses of CRISPR-Cas9 and 8µg CRISPR-Cas9 was the most optimal concentration with the efficiency of 100% and approximately 0% insertion-deletion (INDEL). Fifty days after gene editing, the INDEL increased to only 2%, indicating a minimum residual CRISPR-Cas9 effect in edited cells. The exome-NGS analysis also showed no off-target effects in the outside target area. Functional studies showed that there was a significant increase in wildtype GJB2 mRNA expression and a reduction of mutant GJB2 expression (n = 5, P < 0.01). Increased Cx26 membranous localization in KID-KCs was also observed (n = 3, P < 0.01). Additionally, Cx26 hemichannel activity assessment using the neurobiotin assay showed a significant decrease in ‘leaky’ hemichannel in gene-edited KID-KCs compared with unedited cells (n = 3, P < 0.05).

Conclusions

We can genome-correct KID keratinocytes harbouring the mutation D50N with 100% editing efficiency, 0–2% INDEL, and undetectable off-target effects. This result indicates a promising gene therapy for KID syndrome with the hotspot mutation D50N.
O21 Raman spectroscopy for detection of squamous cell carcinoma in recessive dystrophic epidermolysis bullosa skin
Authors: Dimitrievska Marija , Chiappini Ciro , McGrath John , Bergholt Mads S
Published: May 2024

Introduction and aims

Recessive dystrophic epidermolysis bullosa (RDEB) is a genetic skin disorder caused by biallelic pathogenic variants in COL7A1, which encodes type VII collagen (C7). Lack of C7 leads to blistering, chronic wounds, scarring and early onset of life-shortening squamous cell carcinomas (SCCs). Currently, the suspicion of SCC is mostly determined by clinical observation of visible changes in chronic wounds, and often requires multiple biopsies for histological diagnosis. This project aims to improve clinical care by developing a new noninvasive means of detecting SCC. To achieve this, we used Raman spectroscopy, a nondestructive analytical technique to study the changes occurring in RDEB skin when SCC is present, with the goal of creating a bedside test that can aid clinicians in the early diagnosis of SCC.

Methods

Raman spectroscopic imaging was performed on 7-µm frozen skin sections from RDEB (n = 3), RDEB SCC (n = 3) and normal skin (n = 3) to identify signalling changes between nonlesional and lesional states. An in-depth molecular composition analysis of the samples was performed using multivariate analysis with the goal of highlighting changes in abundance of specific molecules when SCC is present.

Results

For both nonmalignant and RDEB SCC skin sites we found specific Raman peaks associated with protein (1004 cm−1, 1650 cm−1) or lipids (1450 cm−1). RDEB SCC indicated a relative increase in DNA and protein. High-quality Raman spectroscopic images could be acquired that showed clear correlation with histological appearances. Current work is under way to determine which specific biological compounds contribute to the Raman spectra observed.

Conclusions

Raman spectroscopic imaging can provide comprehensive and noninvasive molecular tissue mapping with resolution comparable to histological sections, enabling molecular-based detection of SCC. Future work will focus on characterization of the SCC molecular profile, in addition to determining whether fibre optic Raman spectroscopy can be used to guide the biopsy/resection of RDEB lesions.
P08 Exploring the role of cellular senescence in cutaneous repair
Authors: Johns Alexander , Wilkinson Holly
Published: May 2024

Introduction and aims

Chronic nonhealing wounds are a life-threatening skin disease in elderly patients and patients with diabetes that costs the National Health Service over £8 billion per year to treat. Unfortunately, current treatments are inadequate, thus there is an urgent need to develop effective therapies. Cellular senescence is emerging as a potential therapeutic target owing to its association with a wide range of age-related pathologies. Cells undergo senescence in response to ageing and stress, losing their ability to proliferate or perform normal tissue functions. Our previous work in mice provided the first mechanistic demonstration that senescent cell accumulation drives poor healing. Moreover, clinical trials currently assessing the efficacy of senescence-targeted drugs (senolytics) are providing repurposing opportunities for cutaneous pathologies. Therefore, the aim of this research is to (i) investigate the role of senescence in human chronic wounds and (ii) determine whether senolytics can be repurposed to promote pathological skin repair.

Methods

Skin and wounds were collected from healthy, aged and diabetic donors to quantify senescence levels (senescence-associated β-galactosidase), characterize senescent cell types (immunofluorescence) and determine key drivers of skin senescence (RNA sequencing). Additionally, we screened the wound healing potential of a panel of senolytics in healthy skin vs. skin from patients with chronic wounds.

Results

We found significant accumulation of senescence in pathological skin wounds, localized to stromal cells. Senescence levels also correlated substantially with clinical parameters, such as wound site, diabetic status and infection. RNA sequencing revealed key links between senescence and immunity, suggesting inflammation as a crucial driver of skin senescence. Finally, senolytic treatment significantly accelerated healing in skin from patients with chronic wounds.

Conclusions

Our data provide the first in-depth characterization of senescence in human chronic skin wounds, crucially identifying novel therapeutic targets of senescence, while simultaneously assessing the potential of drug repurposing for patient benefit.
P11 A role for keratinocyte arginase in skin wound healing and barrier function
Authors: Szondi Denis-Cristian , Cruickshank Sheena , Vardy Leah , Wong Jason
Published: May 2024

Introduction and aims

Delayed cutaneous wound healing is a major problem that can result in social isolation and significant morbidity including amputation. There are many changes in cellular function in a chronic wound. Notably, the enzyme arginase (ARG)1 is markedly changed in wound healing. We have identified a role for ARG1 in keratinocyte re-epithelialization during wound closure, but the underlying mechanism driving re-epithelialization was not known. We aimed to determine the role of ARG1 in keratinocyte migration, differentiation and barrier formation.

Methods

Two-dimensional scratch and differentiation assays using immortalized keratinocytes (NTERT cells) treated with the ARG1 inhibitor, nor-NOHA, and short hairpin RNA-based knockdown cells were assessed. Gene and protein expression changes were highlighted. Expression of proteins was further validated using immunohistochemical profiling of human skin equivalents and human wound lesions by spatial transcriptomics.

Results

ARG1 was strongly expressed both 2–4h postscratching and at late stages of keratinocyte differentiation. Dysregulation of ARG1 expression was spatially highlighted in chronic lesions, further suggesting an involvement in keratinocyte migration and differentiation. ARG1 inhibition led to a significant delay in postscratch keratinocyte migration. Furthermore, upon ARG1 inhibition, a significant decrease was seen in the expression of late differentiation markers involucrin and filaggrin. ARG1 inhibition significantly decreased the expression of host defence genes β-defensin 3, lipocalin 2 and kallikrein 6. ARG1 triggers production of multiple downstream products and we confirmed a role for the pathway involving production of putrescine and urea, as the addition of these metabolites led to the rescue of these phenotypes.

Conclusions

ARG1 and its downstream metabolites play a major role in keratinocyte migration, differentiation, and barrier formation, which are vital functions for re-epithelialization and wound closure. Therefore, manipulation of the ARG1 pathway may be crucial in the management of chronic lesions.
P18 Investigating the role of the microbiome in chronic wound skin barrier reformation
Authors: Cannon Alice , Wilkinson Holly , Rudden Michelle , Hardman Mat
Published: May 2024

Introduction and aims

The integrity of the skin barrier plays a pivotal role in dermatological health, particularly in elderly and individuals with diabetes who are more susceptible to injury. Our skin barrier is also in direct contact with the microbiota, a diverse community of microorganisms that play wide-ranging roles in cutaneous function. Although microbial dysbiosis has been observed in elderly and diabetic skin, few studies have investigated the mechanistic links between skin barrier perturbations and the microbiome. The aim of this study was to compare barrier reformation in healthy and pathological (chronic wound) skin and determine the role of microbial dysbiosis in skin barrier perturbations.

Methods

Here, we developed a novel human ex vivo skin barrier model to simulate skin barrier disruption in healthy and pathological skin. Following tape stripping (n = 6 per donor type), skin barrier disruption was confirmed by measuring transepidermal water loss (TEWL). Skin barrier reformation was assessed following culture using haematoxylin and eosin staining, Nile red (lipid expression and distribution), and immunohistochemistry for skin barrier proteins (e.g. claudins, keratins). Secreted products from mixed bacterial communities were also applied to healthy tape-stripped skin to assess the influence of a healthy vs. pathological microbiome on skin barrier reformation.

Results

Pathological skin showed higher TEWL following barrier disruption, in addition to delayed barrier reformation and altered skin barrier protein expression. Moreover, secreted products from a pathological microbiome, with high proportions of Staphylococcus aureus, significantly delayed skin barrier reformation.

Conclusions

Collectively, our data provide a novel skin barrier reformation model to assess the effect of cutaneous pathology and microbial dysbiosis on skin barrier repair. Further understanding of the role of the microbiome in skin barrier function is integral to reducing infections and barrier perturbation.