bluuebunny/crossref_metadata_2025 huggingface dataset:
Two dimensional simulations to study the relationship between settling velocity and flexibility of a particle
Authors: Panghal Rekha , Ghosh Sudeshna , Sharma Amit
Published: May 2024

In various industrial and real-life scenarios, sedimentation, whether involving flexible fibres, permeable structures, or a combination of both, plays a pivotal role. Its impact spans from influencing paper properties to waste water treatment and microorganism transport dynamics. Understanding sedimentation is crucial for optimizing processes like flocculation, organic matter removal, and particulate material management. Settling velocity, a key metric, is vital in designing instruments and formulating optimization strategies across environmental engineering and sediment transport. Despite extensive research on settling velocity correlations with viscosity, structure density, and permeability, the relationship with structural flexibility remains unexplored. This study employs the Immersed Boundary (IB) method, utilizing a MATLAB code to numerically investigate the correlation between settling velocity and the flexibility of settling structures, addressing a gap in prior research. The results demonstrate a robust correlation between settling velocity and flexibility, supported by high R-squared values (ranging from 0.9979 to 1) for exponential fits across all discussed cases. The R-squared value, a statistical measure assessing model accuracy, reinforces the superiority of the exponential fit in describing the settling velocity-flexibility relationship. To confirm the optimal fit, we conducted fitting attempts with various curve types using MATLAB, encompassing polynomial, Fourier, and smooth spline curves for both impermeable and permeable structures. The exponential curve consistently emerged as the most fitting model in this context.In our recent research, we conducted a sensitivity analysis focusing on the time-step to validate the robustness of our findings. The investigation encompassed both impermeable and permeable scenarios for the structures under study. The time-step was systematically varied across a specified range, revealing a notable outcome: the results demonstrated a consistent independence from the chosen time-step values.
Subtraction of liposome signals in cryo-EM structural determination of protein–liposome complexes
Authors: Li 李 Shouqing 首卿 , Li 李 Ming 明 , Wang 王 Yumei 玉梅 , Li 李 Xueming 雪明
Published: May 2024

Reconstituting membrane proteins in liposomes and determining their structure is a common method for determining membrane protein structures using single-particle cryo-electron microscopy (cryo-EM). However, the strong signal of liposomes under cryo-EM imaging conditions often interferes with the structural determination of the embedded membrane proteins. Here, we propose a liposome signal subtraction method based on single-particle two-dimensional (2D) classification average images, aimed at enhancing the reconstruction resolution of membrane proteins. We analyzed the signal distribution characteristics of liposomes and proteins within the 2D classification average images of protein–liposome complexes in the frequency domain. Based on this analysis, we designed a method to subtract the liposome signals from the original particle images. After the subtraction, the accuracy of single-particle three-dimensional (3D) alignment was improved, enhancing the resolution of the final 3D reconstruction. We demonstrated this method using a PIEZO1-proteoliposome dataset by improving the resolution of the PIEZO1 protein.
Relating SI units to the ‘defining constants’
Authors: Blattner Peter , Brown Richard J C
Published: May 2024

This contribution discusses the direct relationship of any SI unit to the defining constants. For many of the SI derived units the relationships to the defining constants are simpler than to the SI base units. Furthermore, some of the relationships directly reflect the fundamental quantum-physical effects that are exploited in the primary realisation of units. It is not the intention of this article to question the status of the seven SI base units and the distinction between the SI base units and the SI derived units, which have evolved historically and persist for pedagogical reasons, but instead to provide an alternative view of the SI. This alternative view also allows a broader and more modern presentation of metrology in general and demonstrates that, in respect of the ability to be directly realised from the defining constants, there is little practical difference between the SI base units and SI derived units.
Self-supervised motor imagery EEG recognition model based on 1-D MTCNN-LSTM network
Authors: Cunlin Hu , Ye Ye , Nenggang Xie
Published: May 2024

Objective. Aiming for the research on the brain–computer interface (BCI), it is crucial to design a MI-EEG recognition model, possessing a high classification accuracy and strong generalization ability, and not relying on a large number of labeled training samples. Approach. In this paper, we propose a self-supervised MI-EEG recognition method based on self-supervised learning with one-dimensional multi-task convolutional neural networks and long short-term memory (1-D MTCNN-LSTM). The model is divided into two stages: signal transform identification stage and pattern recognition stage. In the signal transform recognition phase, the signal transform dataset is recognized by the upstream 1-D MTCNN-LSTM network model. Subsequently, the backbone network from the signal transform identification phase is transferred to the pattern recognition phase. Then, it is fine-tuned using a trace amount of labeled data to finally obtain the motion recognition model. Main results. The upstream stage of this study achieves more than 95% recognition accuracy for EEG signal transforms, up to 100%. For MI-EEG pattern recognition, the model obtained recognition accuracies of 82.04% and 87.14% with F1 scores of 0.7856 and 0.839 on the datasets of BCIC-IV-2b and BCIC-IV-2a. Significance. The improved accuracy proves the superiority of the proposed method. It is prospected to be a method for accurate classification of MI-EEG in the BCI system.
Trajectory planning and simulation of upper limb rehabilitation robot based on NSGA2
Authors: Yao Hengwen , Duan Fuhai , Wang Xiaobin
Published: May 2024

In order to increase the stability and comfort of hemiplegic rehabilitation training, this paper integrates B-spline curves with a non-dominated sorting genetic algorithm (NSGA2) for trajectory planning of a 5-DOF upper limb exoskeleton rehabilitation robot, the structural characteristics of the robot are analyzed. Subsequently, the forward kinematics equation is derived by the D-H method, and its correctness is verified by Adams simulation. Subsequently, the robot workspace is calculated, and the outcomes show that it satisfies the patient’s demand for activity. Finally, the trajectory curve is constructed using the 5th-order B-splines. Under kinematic constraints, the NAGA2 is used to discover the ideal time interval sequence for time, impact and energy, and then complete the trajectory planning. The simulation findings demonstrate the suggested trajectory planning method produces continuous, smooth, and high-performance motion trajectories, providing good rehabilitation training for patients.
Rolling bearing fault diagnosis based on multi-source data fusion
Authors: Li Haomiao
Published: May 2024

In this paper, a fault diagnosis method is proposed based on multi-source data fusion to address the inaccurate results caused by single evidence used for decision-making. First, empirical mode decomposition is performed using sensor data to extract fault features, and a fault feature matrix and a diagnostic matrix are established. Then the deviation vector is defined to obtain the difference between the diagnostic sample and the fault sample, and then the basic probability assignment is obtained for each diagnostic sample. Finally, the Dempster combination rule is used for fusion. The effectiveness and accuracy of this method in fault diagnosis of rolling bearings have been verified through examples of rolling bearings.
Research on linear/nonlinear active disturbance rejection switching control of PMSM speed servo system
Authors: Wang Yilin , Liu Huibo
Published: May 2024

An improved linear/nonlinear active disturbance rejection switching control strategy is proposed to enhance the dynamic response and disturbance suppression capabilities of the permanent magnet synchronous motor (PMSM) speed servo system. Firstly, facilitated by a tracking differentiator, rapid setpoint tracking is achieved without speed overshoot, effectively addressing the inherent conflict between fast system response and overshooting. Secondly, weight factors are introduced into the control law, and a novel switching criterion based on the step function is designed, enabling the system to smoothly transition between operating modes in the presence of disturbances with varying amplitudes. This facilitates accurate estimation and swift compensation for disturbances, thereby enhancing control precision and robustness. Additionally, a frequency domain analysis of the extended state observer is conducted, leading to the formulation of a parameter tuning scheme for the controller. Lastly, simulation tests validate the feasibility and effectiveness of this strategy as a PMSM speed controller. The system exhibits superior dynamic tracking and disturbance suppression performance over a wide speed range.
Design of class f reconfigurable power amplifiers
Authors: Liu Wenjin , Dong Haojie , Nan Jingchang
Published: May 2024

With the rapid development of mobile communication technology, RF amplifier requirements becoming higher, miniaturization, high efficiency and multi-band have gradually become a research hotspot. Based on these hot research directions, this paper designs a dual-band reconfigurable power amplifier. The input of the amplifier adopts a stepped impedance matching network, which has a good matching effect in the 1.6 - 2.8 GHz band. The output is switched by a single-knife double-throw switch to the corresponding band output matching network to achieve the fast switching of different frequency bands. The RF amplifier tube is designed by using Cree’s GaN chip CGH40010F, which has an additional power efficiency of more than 60% in the frequency range of 1.7 - 1.9 GHz and 2.5 - 2.7 GHz bands, a gain of about 12 - 14 dB and a saturated output power of more than 40 dBm. This design has the features of high efficiency, high gain, miniaturization and multi-band, which is applicable to the mobile communication system.
A novel method for cycle slip detection and restoration of BDS carrier phase
Authors: Yuan Zhenguo
Published: May 2024

The chief purpose of this present study is to develop a new approach to cycle slip detection and restoration of the BeiDou Navigation Satellite System (BDS) carrier phase. Based on the RAIM algorithm in the application of aviation safety, we extend the application to ensure the precision of the carrier phase. To stand-alone receivers of a low-cost single frequency, carrier phase data is made different between adjacent epochs. Then least-square residuals were to design a RAIM scheme with differential carrier phase data to find out the epoch with cycle slip, and finally repair cycle slip by Chebyshev polynomial. Results indicate that the approach can detect cycle slip effectively and both big cycle slip and small cycle slip could be repaired.
Calculation of spontaneous radiation during channeling of relativistic positrons in non-chiral nanotubes using a quadratic approximation
Authors: Maksyuta N.V. , Vysotskii V.I. , Maksyuta D.N. , Efimenko S.V. , Slinchenko Yu.A.
Published: May 2024

The work investigates the conditions for the possibility of using the quadratic
approximation U(ρ) = αρ2 for the interaction potentials of channeled
positrons with the inner walls of non-chiral carbon nanotubes of types (n, 0) and
(n, n). In particular, (8, 0), (10, 0), (12, 0) and (8, 8), (10, 10), (12, 12)
nanotubes were selected. In this case, when calculating the single-particle potential of the
carbon atom, only the contribution of valence electrons was taken into account. As a result of
this approximation, the parameters α were determined for all the nanotubes
studied. Using wave functions and the corresponding quantum levels of transverse energy obtained
by solving the Schrödinger equation, the probabilities of occupation of these levels were
calculated for positron beams with zero angular dispersion moving along the axes of
nanotubes. Based on this information, values of the longitudinal energy of positrons for which the
quadratic approximation is applicable were determined for all the studied nanotubes. Spectral
distributions of spontaneous radiation were calculated in the dipole approximation for
non-dispersive relativistic positron beams, both within the framework of quantum-mechanical and
classical approaches.
CMS ECAL VFE design, production and testing
Authors: Lustermann W. , Abadjiev D. , Dissertori G. , Dejardin M. , Gadek T. , Martin L.T. , Stachon K. ,   the CMS collaboration
Published: May 2024

Maintaining the required performance of the CMS electromagnetic calorimeter (ECAL) barrel at the High-Luminosity Large Hadron Collider (HL-LHC) requires the replacement of the entire on-detector electronics. 12240 new very front end (VFE) cards will amplify and digitize the signals of
61200
lead-tungstate crystals instrumented with avalanche photodiodes. The VFE cards host five channels of CATIA pre-amplifier ASICs followed by LiTE-DTU ASICs, which digitize signals with 160 MS/s and 12bit resolution. We present the strategy and infrastructure developed for achieving the required reliability of less than 0.5% failing channels over the expected lifetime of 20 years. This includes the choice of standards, design for reliability and manufacturing, as well as factory acceptance tests, reception testing, environmental stress screening and calibration of the VFE cards.
Almost isotropy-maximal manifolds of non-negative curvature
Authors: Dong Zheting , Escher Christine , Searle Catherine
Published: May 2024

We extend the equivariant classification results of Escher and Searle for closed, simply connected, Riemannian

n
n

-manifolds with non-negative sectional curvature admitting isometric isotropy-maximal torus actions to the class of such manifolds admitting isometric strictly almost isotropy-maximal torus actions. In particular, we prove that any such manifold is equivariantly diffeomorphic to the free, linear quotient by a torus of a product of spheres of dimensions greater than or equal to three.
Phenomenology and the Norms of Perception
Authors: Doyon Maxime
Published: May 2024

In the philosophical literature, it is customary to think of perception as being assessable with respect to epistemic norms. For example, the whole discussion around disjunctivism, which is now often considered to be the dominant, if not the default, position in philosophy of perception, is framed and motivated by epistemological concerns about truth and falsity. This book argues that perception is normative in another, more fundamental, sense. Perception is governed by norms that I call perceptual, that is, immanent to its own structure. This does not mean that perceptual norms are cut off from external facts; rather, it means that they are constitutive moments of our experience of these facts. Perceptual norms are constitutive or enabling norms in that they establish what perception is. To articulate this, the book draws on the repertoire of the phenomenological tradition, in the work of Edmund Husserl and Maurice Merleau-Ponty in particular. For both phenomenologists, perception obtains when it unfolds concordantly or coherently, and when the perceptual progression corresponds to one’s goal or interest, perception can also be said to be optimal. From the phenomenological point of view, concordance and optimality are the basic perceptual norms governing perceptual experience, and the book clarifies their meaning and addresses the philosophical consequences that follow. The first two chapters outline Husserl’s and Merleau-Ponty’s account of perception, illusions, and hallucinations. The following five chapters put the author’s theory to test in the broader philosophical landscape by engaging in five ongoing debates in philosophy of mind and perception.
Perceptual Normativity in Merleau-Ponty
Authors: Doyon Maxime
Published: May 2024

Despite Merleau-Ponty’s well-known reservations about some aspects of Husserlian phenomenology, this chapter shows that the analyses of perceptual experiences carried out in the Phenomenology of Perception accord with Husserl’s on a fundamental respect: like for Husserl, Merleau-Ponty conceives of perception, illusions, and hallucinations both in intentional and normative terms. After having shown the role of the norms of concordance (Section 2.1) and optimality (Section 2.2) in Merleau-Ponty’s account of perceptions, the chapter provides a detailed analysis of his phenomenological conception of illusion (Section 2.3) and hallucination (Section 2.4) in turn, exposing how Merleau-Ponty defines both types of experiences in terms of the specific ways they break with the norms of regular perceptual experiencing. Throughout, the chapter insists more on the commonalities than on the differences between Husserl’s and Merleau-Ponty’s accounts of perceptual experience and demonstrates how both phenomenologists deal with the threat of scepticism (Section 2.5).
Perceiving Together
Authors: Doyon Maxime
Published: May 2024

Over the last three decades the phenomenon of ‘sharing’ has been the object of many discussions in the field of collective intentionality or social ontology, whose discussions typically revolve around the paradigmatic cases of ‘shared actions’, which include, without being limited to, shared perceptions. By developing an account of shared perceptual responsiveness, this chapter specifies the correct way to satisfy the required conditions of shared perception: a perceptual We emerges in the way individuals jointly respond to commonly perceived cues. Throughout, the chapter stresses the fundamental role of embodied agency and pre-reflectively experienced time, the two pillars upon which shared perceptual responses rest. It is argued that co-experiencers typically display their normative sensitivity to shared perceptual situations by acting in certain typical ways (and not others), which is in turn only possible if they share a temporal horizon. Ultimately, shared perceptual responsiveness rests on a shared sense of time.
The Never-Ending Problem of Demarcation: Addressing the Air/Space Boundary Issue in International and Domestic Law
Authors: Newman Christopher J
Published: May 2024

This chapter examines the various legal approaches to demarcation of airspace and outer space. It will look at the issues in identifying the legal boundary at which sovereign air law ceases and an object or individual enters outer space. This discussion critically re-evaluates two approaches to identifying the boundary. The first of these, the spatialist approach, ascribes a specific altitude, such as the Kármán line. The second, the functionalist approach, takes a holistic view of the function and purpose of a spacecraft to determine the applicable regime. Neither of these propositions is without their difficulties and this chapter will look at the challenges posed by the development of launch solutions throughout the twenty-first century and the issues that these advances in technology present. It is contended that the problem of demarcation will need a legally certain position as human space activity develops if a conflict is to be avoided.
The Contribution of the United Nations to the Development of International Space Law
Authors: Freeland Steven , Martin Anne-Sophie
Published: May 2024

The international legal framework for outer space activities has largely been developed through the consensus process within the Vienna-based United Nations Committee on the Peaceful Uses of Outer Space (UNCOPUOS), the primary multilateral fora dealing with the exploration and use of outer space for peaceful purposes. The UNCOPUOS has made a remarkable contribution to the development of the international regulatory framework for space through the adoption of five binding Treaties, five sets of United Nations General Assembly (UNGA) Principles, as well as an array of other ‘soft law’ instruments. This chapter examines the development of this international regulatory framework within the UNCOPUOS, and the major role it continues to play in promoting international cooperation in the field of space exploration. Lastly, it discusses the evolution of this framework within the security perspective of space activities addressed by the First Committee of the UNGA and in the Conference on Disarmament (CD).
The Artemis Accords and Subsequent Developments
Authors: de Zwart Melissa , Lisk Joel
Published: May 2024

NASA announced the formation of the Artemis Accords in 2020 with eight foundation partners: Australia, Canada, Italy, Japan, Luxembourg, the United Arab Emirates, the United Kingdom and the United States. As of August 2023, this number has grown to 28. The Artemis Accords provide a blueprint for engagement by these countries on a bilateral basis with NASA on projects which involve the creation of a Lunar Gateway, the return of humans to the Moon and, ultimately, on to Mars. The first Artemis launch occurred in 2022. The content of the Artemis Accords to which a partner agency must agree are expressed to ‘reinforce and implement the Outer Space Treaty, the Registration Convention, the Agreement on the Rescue and Return of Astronauts’ and ‘other norms of behaviour that NASA and its partners have supported’. However, some of the Artemis principles extend beyond these fundamentals of space law to embrace concepts such as safety zones, resource extraction and use and interoperability. These provisions provide challenges to which evolving international space law must respond. This chapter examines the process and provisions of the US-led Artemis Accords, looking at the content and operation of the individual principles contained therein. It also considers whether the Artemis principles represent a unilateral challenge to existing international space law and concludes that, whilst activities undertaken pursuant to the Artemis projects will inevitably create new norms and behaviours, and, in time, laws, the Artemis principles reflect an evolution which will be necessary as humans expand their activities beyond Earth.
O02 Ubiquitomics of CYLD-deficient skin tumours reveals dysregulation of hair follicle keratinocyte processes
Authors: Inns Joseph , Frey Andrew , Rajan Neil
Published: May 2024

Introduction and aims

CYLD cutaneous syndrome (CCS) is an inherited hair follicle tumour syndrome where biallelic loss of function of the deubiquitinase enzyme CYLD gives rise to cylindroma skin tumours. The role of CYLD in skin biology is not well characterized but it is known to regulate several cell signalling pathways through deubiquitination of effector proteins. We aimed to determine how loss of CYLD function can lead to CCS skin tumour formation by studying the ubiquitome of CCS tumours and healthy skin.

Methods

Healthy skin (n = 5) and CCS tumour tissue (n = 5) were collected from flash frozen samples. Lysed homogenates were trypsin-digested and the resulting peptides underwent diglycine immunopurification for subsequent liquid chromatography–tandem mass spectrometry analysis on a Bruker Tims-TOF HT (Billerica, MA, USA) mass spectrometer. We utilized a data-independent acquisition method adapted for diglycine-containing peptides to generate mass spectrometry data. Peptide identification was performed by searching mass spectrometry data against an in silico neural network derived spectral library with diglycine modification.

Results

We identified 1273 ubiquitination sites across 649 proteins in CCS tumour and control samples. After performing t-tests (P < 0.05), we found 305 ubiquitination sites that were either unique to their respective condition or were differentially regulated. Analysis of ubiquitinated peptide sequences uncovered cell surface receptors with increased ubiquitination in CCS tumour samples including the insulin receptor, which had ubiquitination modifications at its kinase domain, suggesting increased insulin signalling in CCS tumours. Gene set enrichment analysis of CCS tumour ubiquitinated substrates revealed increased ubiquitination of secretory granules and extracellular exosomes, suggesting that loss of CYLD may disrupt regulation of protein secretion processes.

Conclusions

Our findings describe the ubiquitome of CCS keratinocytes, providing insights into how loss of CYLD function can affect biological processes in skin.
O04 Delineation of psoriasis from uninvolved skin using an artificial neural network as a means of targeting phototherapy to psoriatic lesions
Authors: Scott Joseph , Praeger Matthew , James Grant-Jacobs , Barnsley Josephine , Niranjan Mahesan , Eason Robert , Mills Ben , Healy Eugene
Published: May 2024

Introduction and aims

Narrowband ultraviolet B therapy (NB-UVB) is an effective treatment for psoriasis. Currently, NB-UVB is delivered in whole-body cabinets to all of the patient’s skin, thus increasing the risk of normal skin sunburning and the potential risk of skin cancer development. This limits the NB-UVB doses that can be used and requires patients attend sessions three times weekly for up to 10 weeks in order to complete treatment. An artificial intelligence (AI)-mediated, targeted NB-UVB approach would avoid these risks and allow use of higher NB-UVB doses for the areas of the skin affected by psoriasis. We sought to train an artificial neural network on digital images of psoriasis, and subsequently test this trained model in order to assess its accuracy at distinguishing psoriasis from unaffected skin.

Methods

Overall, 104 digital images of psoriasis from 14 patients with this skin condition, who attended the dermatology department at University Hospital Southampton NHS Foundation Trust, were used to train a conditional generative adversarial network– ‘pix2pix’. Areas of psoriasis were delineated within the images prior to the images being augmented by randomly cropping, rotating and altering colour intensity, thereby increasing the total number to 23 111 images to train and test the neural network.

Results

The trained neural network was able to identify psoriasis in unseen digital images with 96.73% accuracy at the pixel level across the dataset. The output of the neural network (i.e. a computer-generated image of psoriasis) acted as a signal source for a digital micromirror device (DMD) that was able to shape visible light and project this light over the original image of psoriasis, while avoiding the uninvolved skin.

Conclusions

It is possible to differentiate psoriasis from unaffected skin within digital images using an artificial neural network. We demonstrated that AI-mediated targeted phototherapy using a DMD is feasible.
O09 Microsatellite-unstable sporadic sebaceous and duodenal tumours are associated with loss of mismatch protein expression
Authors: Holt Georgie , Alfailakawi Waleed , Cook Sam , Ness Thomas , Coulthard Rowen , Jones Claire , Hayes Christine , Phelps Rachel , Kist Ralf , Jackson Mike , Santibanez-Koref Mauro , Burn John , Burt Alastair , Husain Akhtar , Lamb Chris , Gallon Richard , Rajan Neil
Published: May 2024

Introduction and aims

Lynch syndrome (LS) is a common heritable cancer predisposition syndrome. Tumours from patients with LS demonstrate microsatellite instability (MSI-high), a genetic signature detectable by low-cost DNA sequencing assays that is currently utilized in colorectal cancer screening. The utility of MSI assays for LS detection has not been extensively studied in unselected sebaceous skin tumours or duodenal tumours, where currently immunohistochemical (IHC) expression of mismatch repair (MMR) proteins is used. In addition, it has recently been suggested that cutaneous squamous cell carcinoma (cSCC) could be linked to LS; however MSI status has not been studied in patients with early-onset cSCC.

Methods

We investigated MSI status in archival formalin-fixed paraffin-embedded cases with ethical approval. We examined 110 sebaceous tumours (STs) (45 female patients, 65 male patients; median age 77 years), 50 duodenal tumours (DTs) (28 female patients, 22 male patients; median age 64 years), and 148 cSCCs selected from patients under 50 years of age (69 female patients, 79 male patients; median age 49 years). Immunohistochemistry (IHC) was performed on each MSI-high sample to determine the expression of MMR proteins MLH1, MSH2, MSH6 and PMS2. Samples that passed quality control were included in the analysis.

Results

A total of 42 of 106 STs (39.6%) were MSI-high. All STs had loss of at least one MMR protein. Overall, 10 of 41 (24%) DTs were MSI-high. All DTs had loss of at least one MMR protein. We found that 12 of 148 (8.1%) cSCCs were MSI-high and 5 of 12 SCCs exhibited loss of at least one MMR protein expression (41%).

Conclusions

MSI-high status correlated well with loss of MMR protein expression in STs and DTs samples. Future studies will help establish MSI status in tumours initially selected by MMR loss on IHC, informing its use as an adjunct to MMR IHC in LS detection in patients with STs and DTs.
O14 Monocytes and macrophages in the melanoma tumour microenvironment express Fc receptors which can be engaged with monoclonal antibodies of different isotypes
Authors: Adams Rebecca , Osborn Gabriel , Laddach Roman , Grandits Melanie , Chenoweth Alicia , Sanz-Moreno Victoria , Lacy Katie , Karagiannis Sophia
Published: May 2024

Introduction and aims

Melanoma is the deadliest form of skin cancer and has an increasing worldwide incidence. It is well established that the melanoma tumour microenvironment (TME) has a large immune cell infiltrate, including a prominent monocytic compartment. Monocytic cells within the TME support melanoma growth, survival and metastasis. Contrastingly, such cells can be stimulated to promote tumour killing when engaged with monoclonal antibodies (mAbs) against cancer antigens, owing to their expression of multiple Fc receptors (FcRs). However, little is known about the monocytic subsets present within melanoma, the FcRs they express and how engaging their FcRs may influence function.

Methods

Flow cytometry on peripheral monocytes isolated from patients with melanoma and healthy volunteers enabled the characterization of cell surface markers. Next, publicly available single-cell RNA-Seq datasets were analysed to explore the transcriptome of melanoma-associated macrophages and these phenotypes were recapitulated in vitro. Finally, monocytes and macrophages were cocultured with melanoma cells, with or without the addition of mAbs against a melanoma antigen, in order to assess the effect of FcR crosslinking on monocyte and macrophage phenotype and function.

Results

Circulating monocytes in patients with melanoma feature an inhibitory phenotype, and express multiple FcRs, including Fcε and Fcγ receptors, which could be targeted with mAbs of multiple isotypes. Secondly, monocytic cells within the melanoma TME express protumour genes, including metalloproteinases and angiogenic factors. However, FcR expression suggests that tumour-promoting subsets can be targeted with mAbs. Finally, in ex vivo cocultures with melanoma cells, the FcRs of both human monocytes and macrophages are able to engage antimelanoma mAbs of multiple isotypes, inducing differential phenotype change. This is demonstrated by the upregulation of activation markers and costimulatory cell surface markers.

Conclusions

Together, these data suggest that tumour-promoting monocytic cells within the melanoma TME can be engaged and harnessed using different isotypes of mAbs targeting melanoma.
O19 Improvement of a junctional epidermolysis bullosa mouse model
Authors: Jones Eleri , Garcha Priya , Aumailley Monique , O’Toole Edel , Rognoni Emanuel , Caley Matthew
Published: May 2024

Introduction and aims

Junctional epidermolysis bullosa (JEB) is the most severe of the epidermolysis bullosa (EB) disorders and is caused by mutations in genes encoding the skin basement membrane proteins laminin 332, type XVII collagen or integrin α6β4. Affected individuals experience blistering from birth leading to scarring, granulation tissue and susceptibility to infection. In JEB, generalized severe, there is 50% mortality in the first 2 years of life, often owing to failure to thrive or overwhelming infection. A number of animal models for JEB exist; however, because of severe blistering on the entire surface of the skin, these mice die soon after birth, reducing their experimental utility. In 2017, the first adult inducible knockout mouse model of JEB was published. In this mouse model, the disruption of the Lama3 gene is specifically induced in epidermal basal keratinocytes after birth. These mice remain viable, which allows us to study the longer-term consequences of the loss of laminin α3. However, the mice did not develop the severe phenotype observed in patients with JEB.

Methods

We have optimized this previously published methodology of a conditional knockout JEB mouse model (Lama3flx/flxK14CreERT) to now include more regular tamoxifen injections, which Results in a more controlled and severe phenotype of JEB.

Results

Widespread skin blistering develops after 12 weeks of tamoxifen treatment with an impaired skin barrier (transepidermal water loss) and a loss of epidermal lipids. Immunofluorescent staining was conducted to assess skin differentiation (K14, transglutaminase 1, loricrin), proliferation (Ki67), basement membrane proteins (laminin α3, laminin β3, laminin γ2, collagen VII) and immune markers (F4/80, Ly6-G/C, CD3, CD79).

Conclusions

These mice recapitulate all key features of human JEB with loss of laminin α3 at the basement membrane, epidermal thickening and visible blisters. This allows us to delve deeper into the functional and downstream pathways affected by the loss of laminin α3 and discover why the prognosis of patients with JEB is so severe.
P03 Anti-ageing effects of oestetrol on the skin: protection from cellular senescence and restoration of dermal architecture
Authors: Cooksey Leah , Fenercioglu Laden , Bernardes Tania , Fearn Alice , Gerard Céline , Dion Valérie , Hardman Matthew , Wilkinson Holly
Published: May 2024

Introduction and aims

Skin is a major endocrine organ, undergoing profound structural and functional alterations in response to hormonal changes. Postmenopause, the rapid decline in circulating 17β-oestradiol (E2) leads to skin ageing, while exogenous E2 administration restores skin function, promoting the regenerative capacity of aged skin. Nevertheless, the risk of off-target effects limits the clinical use of E2 for skin indications. Oestetrol (E4), a natural oestrogenic steroid currently undergoing clinical trials as a hormone replacement therapy, presents a favourable safety profile and could be a suitable alternative to E2. However, as no studies have investigated the effects E4 on skin ageing, the aim of this study was to evaluate the potential of E4 to overcome effects of skin ageing.

Methods

Micro-osmotic pumps were subcutaneously implanted into 14-month-old female mice, allowing sustained systemic delivery of E2 or E4 over 3 weeks. Reversal of skin ageing was assessed via noninvasive skin parameter testing, histological analysis and biomechanics. Aged human dermal fibroblasts were treated with E4 to measure effects on the extracellular matrix deposition (ECM) in vitro. Finally, human keratinocytes were treated with E4 prior to inducing senescence to assess potential protective effects against skin ageing. Readouts included senescence-associated beta galactosidase staining, immunofluorescence and quantitative polymerase chain reaction.

Results

Systemic administration of E4 reversed multiple characteristics of skin ageing. E4 treatment significantly increased skin hydration, stimulated collagen deposition and elevated elastic fibre synthesis. These structural changes improved the biomechanical function of skin, increasing breaking strength and elasticity. In vitro studies confirmed direct anti-ageing activity on multiple cell types. E4 substantially increased ECM deposition in aged human dermal fibroblasts and protected against senescence induction in human keratinocytes.

Conclusions

Collectively, these preclinical data demonstrate significant beneficial effects of E4 on aged skin, strongly supporting future clinical evaluation of E4 to alleviate the effects of skin ageing following menopause.
P05 The aryl hydrocarbon receptor pathway is dysfunctional in atopic dermatitis
Authors: Dawe Hannah , Tosi Isabella , Barker Jonathan , Smith Catherine , Di Meglio Paola
Published: May 2024

Introduction and aims

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by epidermal barrier disruption and type-2 immune dysregulation. While treatment has improved with targeted biologics, clinical response varies, highlighting the need for additional therapeutic strategies. The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor and environmental sensor, which maintains skin barrier integrity and homeostasis by reducing inflammation. Upon activation, AHR induces the expression of CYP1A1, a biomarker of pathway activation and critical for AHR ligand metabolism. Tapinarof, a topical AHR agonist, is approved for psoriasis and is effective in phase III clinical trials in AD, highlighting the importance of this pathway in inflammatory skin disease. Nevertheless, AHR expression is increased in AD skin, leading to the hypothesis that the pathway is dysregulated, thus not exerting its anti-inflammatory effect.

Methods

Here we begin to perform a global investigation of the AHR pathway in AD. We measured AHR and CYP1A1 mRNA expression by quantitative real-time reverse-transcription polymerase chain reaction (qRT-PCR) in healthy and AD skin, with spatial mRNA expression assessed by RNAscope. We also investigated AHR mRNA expression in interleukin (IL)-4 stimulated (100 ng mL−1) normal human epidermal keratinocytes (NHEKs) using qRT-PCR.

Results

We found that AHR mRNA is significantly upregulated in lesional AD (n = 6) compared with healthy skin (n = 9; P < 0.05), whereas CYP1A1 mRNA expression shows a downward trend in lesional AD compared with healthy skin (P = 0.063). The AHR expression pattern differs in lesional AD (n = 7) compared with healthy skin (n = 8), with AHR localizing in the epidermal basal layer. Finally, IL-4 significantly upregulated AHR mRNA (n = 4 wells; P < 0.001) expression in NHEKs compared with unstimulated cells.

Conclusions

Overall, our data have uncovered a dysfunctional AHR pathway in AD, with increased AHR expression, possibly driven by the AD inflammatory milieu, but reduced pathway activation. Further investigations are required to fully dissect this pathway and maximize its potential as a therapeutic target for AD.
P06 A novel drug combination produces a synergistic effect when inhibiting myofibroblast transformation in an in vitro model of hypertrophic scarring
Authors: Lapthorn Alice , Ilg Marcus , Dziewulski Peter , Cellek Selim
Published: May 2024

Introduction and aims

Hypertrophic scars affect 91% of patients with burns and yet, there is currently no effective treatment for their prevention. Myofibroblasts are key cells in the pathogenesis of hypertrophic scars, with the inhibition of myofibroblast transformation having been suggested as an effective therapeutic strategy. We have previously screened 1954 drugs approved by the Food and Drug Administration to identify any that could inhibit myofibroblast transformation. Using this data, the aim of this study was to investigate the individual and combined antimyofibroblast effect of two drug classes.

Methods

Primary human fibroblasts were isolated from the scars of patients with burns, with myofibroblast transformation induced using transforming growth factor (TGF)-β1. Concentration-response curves for drug-class A and drug-class B were constructed at a range of concentrations (0.03–300 µmol L–1), with the In-Cell enzyme-linked immunosorbent assay method used to measure α-smooth muscle actin (α-SMA) expression. Combination experiments were carried out through construction of a concentration-response curve for drug-class A (0.03–100 µmol L–1) in the presence of 3 µmol L–1 of drug-class B.

Results

Both drug classes showed a concentration-dependent antimyofibroblast effect with an IC50 range of 12.2–120.1 µmol L–1 for drug-class A and 1.4–16.7 µmol L–1 for drug-class B. When given in combination the two classes of drugs produced a synergistic effect at all concentrations up to 10 µmol L–1. For example, an 18% reduction α-SMA expression was expected with 1 µmol L–1 of drug-class A and 3 µmol L–1 of drug-class B; however, a 24% reduction in α-SMA expression was observed instead.

Conclusions

This is the first study to identify this synergistic effect between these two drug classes, and therefore this novel drug combination could be developed for the prevention of hypertrophic scar formation.
P12 Transcriptional and epigenetic changes drive increased cellular plasticity in keloid fibroblasts
Authors: Tekkela Stavroula , Hight-Warburton Willow , Shaw Tanya , Philpott Mike , O’Toole Edel , Rognoni Emanuel
Published: May 2024

Introduction and aims

Keloids are fibroproliferative scars that progressively grow beyond the original wound site. They occur as a result of genetic, epigenetic and environmental abnormalities. Fibroblasts are best characterized for their role in depositing and remodelling the extracellular matrix (ECM) and are believed to have a crucial role in keloid formation. However, the detailed molecular signatures that promote this pathogenic phenotype are still unknown.

Methods

To investigate the epigenetic and genetic changes in keloid fibroblasts, we performed assay for transposase-accessible chromatin (ATAC)-Seq and RNA-Seq on a patient-matched set of keloid and normal fibroblasts. ATAC-Seq is a high-throughput sequencing method that defines chromatin accessible regions in which the binding of sites of transcription factors that regulate gene expression can be mapped. Identified candidates are validated in keloid fibroblasts via quantitative polymerase chain reaction and their functional role is analysed in various in vitro assays.

Results

ATAC-Seq analysis revealed more accessibility in coding regions of keloid fibroblasts compared with normal fibroblasts. Pathways enriched in these regions include transcriptional regulation, embryonic development, cell differentiation, calcium-binding and collagen remodelling. Intriguingly, several developmental epigenetic modulators were identified that may alter the transcription and chromatin landscape of keloid fibroblasts to a more plastic state and have the capacity to influence cell differentiation choices, potentially promoting chondrogenic and adipogenic cell features. Currently, we are investigating the ability of keloid fibroblasts to be more readily differentiated into other cell types including induced pluripotent stem cells, and the contribution of those candidates on fibrotic features to the cell are also being explored.

Conclusions

Our analysis reveals that the chromatin of keloid fibroblasts is more accessible, especially in genomic regions associated with embryonic development and keloid fibroblasts show an increased plasticity in vitro. These findings may support the development of fibroblast-targeted therapies for keloid scars and possibly other connective tissue disorders.
P13 Keratinocyte heterogeneity and dynamics in human skin wound healing
Authors: Lee Jia Jun , Higgins Claire
Published: May 2024

Introduction and aims

Human chronic skin wounds have been extensively characterized, but ethical limitations of collecting and studying wounds from healthy individuals means there is a sparsity of data regarding re-epithelialization in normal wound healing. Here, we characterize ex vivo models of wound closure in human skin to better understand the keratinocyte dynamics of normal healing.

Methods

We conducted single-cell RNA sequencing (scRNA-Seq) from ex vivo skin explants 2 days postwounding (n = 4) to interrogate heterogeneity in keratinocytes relative to the wound edge. Immunostaining was also conducted on sections from skin explants at different timepoints during wound closure. Scratch assays were conducted using isolated human keratinocytes. Specific zones of keratinocytes were separated relative to the original scratch, 6 h postscratch, and used for real-time polymerase chain reaction analyses.

Results

We found that partial re-epithelialization and full healing of 2-mm wounds occurred 2–3 days and 4 days postwounding, respectively. Analyses of the scRNA-Seq data showed an increase in S100A7 expression in suprabasal keratinocyte subclusters in wounded skin compared with unwounded skin. Using immunostaining we also showed that S100A7 is expressed at the leading edge of the regenerating epidermis. In an in vitro scratch wound model, the keratinocytes nearest to the wound edge also show an upregulation of S100A7, EGFR, EPHA4 and TIMP1, as well as a downregulation in PCNA, implying a decrease in cell proliferation in leading keratinocytes.

Conclusions

S100A7 was previously reported to be increased at the wound edge in human keratinocytes, highlighting that transcriptional changes in our ex vivo and in vitro human wound healing models reflect those occurring in vivo. The decrease in PCNA in keratinocytes in the leading edge also recapitulates Results previously shown in mouse models of wound healing. These data on normal re-epithelialization will be compared with published data on human chronic wounds and other skin diseases.
P22 A single-cell map of the epigenomic landscape in keratinocytes exposed to the cytokine milieu of atopic dermatitis
Authors: Sadeghi Laia , Ardern-Jones Michael
Published: May 2024

Introduction and aims

In atopic dermatitis (AD), induction of inflammatory responses regulated by cytokines such as of thymic stromal lymphopoietin exacerbate the disrupted integrity of the skin barrier. Cytokines, such as interleukin (IL)-4, IL-13 and IL-22, present in the skin milieu, bind to their corresponding receptors on the cell surface of keratinocytes, activating multiple signal transduction pathways that lead to changes in the gene expression profile of keratinocytes, in part, by modulating chromatin structure. Understanding the intricate interplay between cytokine-mediated signalling pathways in keratinocytes and the resulting epigenetic changes is essential for elucidating the pathogenesis of AD. In this study, we utilized high-throughput technology to examine the effects of cytokines on modulation of the epigenetic landscape at the keratinocyte single-cell level, and subsequent effects on the gene expression.

Methods

We utilized the reconstructed human epidermis model, an in vitro three-dimensional human epidermis model consisting of a polycarbonate membrane and keratinocytes mimicking the structure of native human epidermis. Following exposure to AD cytokine(s), the model gene expression and chromatin accessibility of target cells were analysed using single-cell multiomics approaches.

Results

Our preliminary data show that IL-4, IL-13 and IL-22 reduce the expression levels of the barrier-related gene filaggrin in keratinocytes.

Conclusions

Unlike genetic changes, epigenetic alterations are dynamic and can be restored to their normal state, which has major implications for the development of therapeutics for various diseases. This study will provide valuable insights into the epigenetic mechanisms underlying AD and present potential targets for epigenetic-related therapeutic interventions. These interventions can be used in combination with available compounds to reduce the recurrence of AD and improve the treatment efficiency.