bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling and improvement for the thermal stability of ring-shaped workpieces with shape boundary constraints
Authors: Wang Yong-Jun , Li Rui-Jun , Zhao Liang , Yao Pan , Xu Peng , Ma Shao-Hua , Cheng Zhen-Ying
Published: February 2024

Ring-shaped workpieces are commonly utilized in high-precision measuring instruments, and their thermal deformation affects the instruments’ measuring accuracy. A novel method for establishing the thermal deformation model of ring-shaped workpieces is proposed in this article. The mechanism of thermal deformation caused by shape boundaries is investigated using the principle of molecular dynamics. A mathematical model between deformation degree and height, diameter ratio, or temperature is created using a large-scale atomic/molecular massively parallel simulator. The established model is verified by measuring the thermal deformation of ring-shaped workpieces. The model is used to optimize laser collimation systems, and stability experiments for laser collimation systems in different sizes are performed. The stability of optimized systems can be improved by 50%, 50%, and 48% with temperature increases of 10 °C, 20 °C, and 30 °C, respectively. The experimental results indicate the obtained model can be utilized to improve the stability of instruments.
Simulation alignment of optical system for space gravitational wave telescope
Authors: Yu Miao , Huang Lanjun , Liu Yinghong , Zou Donglan , Lin Hong-an , Li Jiancong , Wang Zhi , Wu Yanxiong
Published: February 2024

The performance of telescopes, important components of space interferometry systems, directly affects the accuracy of gravitational wave signals. Space gravitational wave telescopes typically employ an off-axis four-mirror system. When aligned, this system not only has multiple misalignments, but also exhibits interrelated aberrations from various misalignments. These characteristics may lead to difficult alignment of the telescope system as well as significant deviation between the position of the telescope after alignment and the ideal position. To address these issues, first, a sensitivity matrix equation was established between the misalignment of optical components and the Fringe Zernike coefficients. Based on the sensitivity matrix equation, a damping least-squares evaluation function was constructed to reduce the significant deviation between the aligned and ideal positions. Second, a typical optical system of a space gravitational wave telescope was designed, and the sensitivity matrix was calculated. The relationship between the wavefront distortions caused by misalignments in each optical component was examined. To simplify telescope installation, a strategy using secondary mirrors as compensatory elements was proposed. Finally, to verify the effectiveness of the scheme, 200 sets of tolerance files were randomly generated. Based on the evaluation function of the damping least-squares method, a reasonable damping factor was set to limit the solution range of the misalignment, which enabled calculating the secondary mirror compensation amount. Experimental results indicate that after aligning the 200 random telescope files, the root-mean-square wavefront error was reduced to less than 0.0030λ, and the maximum error between the magnification after alignment and the ideal position magnification was only 0.57%, which confirms the feasibility of this alignment scheme.
Study of electromagnetic damping of an oscillating bar magnet and its energy budget
Authors: Banerjee Avik , Saha Sonali
Published: February 2024

The oscillation of a bar magnet along the axis of a closed loop solenoid has been studied quantitatively using an ultrasonic sensor and Arduino microcontroller-based platform. Real-time displacement of the oscillatory magnet with and without the solenoid shows an additional damping effect due to electromagnetic induction in the presence of the closed-loop solenoid. Variation of the induced current in the solenoid circuit has been analyzed over several cycles by simultaneous recording of the voltage developed across two resistors using ‘analogread’ library function. Energy drained from the oscillator due to electromagnetic damping has been compared with the energy lost in Joule heating of the solenoid circuit. A phase plot for the underdamped oscillator was generated using the fitting parameter values of the curve fitted with the position vs. time data points on the plot. This portable and inexpensive microcontroller-based design is well suited for STEM education of high school and for sophomores in an undergraduate physics course.
An elementary proof of the amplitude’s exponential decrease in damped oscillations
Authors: Kontomaris Stylianos-Vasileios , Malamou Anna
Published: February 2024

A damped oscillation is characterized by the diminishing amplitude of an oscillating system resulting from the dissipation of energy. A crucial example of damped oscillations involves a block of mass attached to the end of a linear spring, experiencing a damping force proportional to the object’s velocity and acting in opposition to the direction of its motion. For small values of the damping constant, the amplitude decreases exponentially over time. Typically, this behavior is introduced at the secondary education level without providing a justification. In this paper, a new approach tailored for the secondary education level is introduced to explain the aforementioned exponential decrease without relying on advanced mathematical tools. In addition, utilizing this analysis simplifies the demonstration of why the exponential decrease in amplitude is applicable only for small damping forces. It is also worth noting that the methods used to derive this result can be applied in various areas, including the derivation of the equation that connects the root mean square value of the AC sinusoidal current to its maximum value.
A modern, rapid and simple investigation of Ampère’s law
Authors: Cicuta Pietro , Organtini Giovanni
Published: February 2024

Classical physics results are often taught purely from the theoretical side. Key results, especially in electromagnetism, are typically not explored experimentally, and in applications students are then expected to leap straight into more complex scenarios that make use of these principles in electronics, sensors and instrumentation. This is unfortunate because not all individuals are equally able to learn well purely from the mathematical angle, and even those who do are not exposed to exploring the magnitude of competing effects, for example isolating a particular magnetic field signal from the background of the Earth’s field. An experiment is presented here to test Ampère’s law with a setup that can be assembled out of everyday materials with minimal components—a smartphone, a DC power supply, wires—in a procedure that can be completed in just a few hours. The data from the three magnetic field sensors of the phones, together with the gyroscope sensors providing position, are recorded and numerically integrated. The experiment is also demonstrated using sensors collected by an Arduino board instead of a smartphone. The experiment allows to measure the net current carried by wires inside the closed path over which the magnetic field is integrated, i.e. Ampère’s law. This experimental approach to exploring Ampère’s Law can be adapted towards high school or university demonstrations, depending on the level of accuracy and detail that one aims to pursue.
A new approach to determining the specific heat using the Arduino® platform and Newton’s law of cooling
Authors: Martins Thalyta de Oliveira Inocêncio , Cruz Frederico Alan de Oliveira , Hahn Marcelo Dumas , Paes Juliana Lobo
Published: February 2024

This article describes a new approach for determining the specific heat of solid and liquid samples in an educational laboratory setting. The experiment employed automated data collection, using Arduino® to record temperatures as the system cooled. Samples of water, ethyl alcohol, lead, and aluminium were analysed by exchanging heat with preheated water in a non-insulated container. To identify the moments when the samples attained thermal equilibrium with the reference liquid, we employed the cooling curve adjusted using Newton’s law of cooling. This correction allowed us to uncover the exact points of equilibrium with enhanced accuracy. The results, both for solid and liquid samples, indicated the effectiveness of the method, due to its reasonable proximity to the expected values (e% < 10). This approach goes beyond the conventional calorimeter, proving its viability in testing various samples and thus enhancing research on the thermal properties of different materials.
Path planning algorithm for percutaneous puncture lung mass biopsy procedure based on the multi-objective constraints and fuzzy optimization
Authors: Zhang Jiayu , Zhang Jing , Han Ping , Chen Xin-Zu , Zhang Yu , Li Wen , Qin Jing , He Ling
Published: February 2024

Objective. The percutaneous puncture lung mass biopsy procedure, which relies on preoperative CT (Computed Tomography) images, is considered the gold standard for determining the benign or malignant nature of lung masses. However, the traditional lung puncture procedure has several issues, including long operation times, a high probability of complications, and high exposure to CT radiation for the patient, as it relies heavily on the surgeon’s clinical experience. Approach. To address these problems, a multi-constrained objective optimization model based on clinical criteria for the percutaneous puncture lung mass biopsy procedure has been proposed. Additionally, based on fuzzy optimization, a multidimensional spatial Pareto front algorithm has been developed for optimal path selection. The algorithm finds optimal paths, which are displayed on 3D images, and provides reference points for clinicians’ surgical path planning. Main results. To evaluate the algorithm’s performance, 25 data sets collected from the Second People’s Hospital of Zigong were used for prospective and retrospective experiments. The results demonstrate that 92% of the optimal paths generated by the algorithm meet the clinicians’ surgical needs. Significance. The algorithm proposed in this paper is innovative in the selection of mass target point, the integration of constraints based on clinical standards, and the utilization of multi-objective optimization algorithm. Comparison experiments have validated the better performance of the proposed algorithm. From a clinical standpoint, the algorithm proposed in this paper has a higher clinical feasibility of the proposed pathway than related studies, which reduces the dependency of the physician’s expertise and clinical experience on pathway planning during the percutaneous puncture lung mass biopsy procedure.
Topological states in honeycomb arrays of implanted acceptors in semiconductors
Authors: Zhu Jianhua , Bhattacharyya Sankalan , Wu Wei , J Fisher Andrew
Published: February 2024

We study a neutral honeycomb array of acceptors in a Group IV semiconductor. Tight-binding exhibits a band gap from different hopping of angular momentum

±

3
2

and

±

1
2

, forming a topological insulator (TI). The hopping is even under separate reversal of spatial and spin motions, unlike spin–orbit coupling. The TI is robust to Coulomb interactions and realistic electronic structure calculations show it survives for a range of spacings and distortions commensurate with the silicon growth surface, but has an instability towards spin density wave formation at large separations.
Monitoring of multiple fabrication parameters of electrospun polymer fibers using mueller matrix analysis
Authors: Sharma Gaurav , Jütte Lennart , Gopani Jigar , Brehme Jules , Günther Axel , Sindelar Ralf , Renz Franz , Roth Bernhard
Published: February 2024

Electrospun polymer fiber mats feature versatile applications in tissue engineering, drug delivery, water treatment and chemical processes. The orientation of fibers within these mats is a crucial factor that significantly influences their properties and performance. However, the analysis of fiber samples using scanning electron microscopy (SEM) has limitations such as time consumption, fixed assembly, and restricted field of vision. Therefore, a fast and reliable method for qualitative measurements of fiber orientation is required. Mueller matrix polarimetry, a well-established method for measuring orientation of chemical and biological species, was employed in this case. We investigated the effect of four important parameters of the electrospinning process, namely collector speed, applied voltage, needle-to-collector distance, and solution concentration, on fiber orientation using Mueller matrix polarimetry thus extending the range of parameters analyzed. Measurements were performed using two extreme values and a central optimized value for each fabrication parameter. Changes in matrix values were observed for each fabrication parameter, and their correlation with fiber orientation was analyzed based on the Lu-Chipman decomposition. The results were compared with SEM images, which served as the ground truth, and showed overall good agreement. In the future, the analysis of electrospun polymer fibers can be done by using Mueller matrix polarimetry as alternative to current technology and fabrication parameters, including solution concentration for the first time in this context and the production can quickly be adjusted based on the outcome of the measurements.
Weak measurement of the Goos–Hänchen shift for a Hermite–Gaussian laser beam
Authors: Mandal Soumen , Das Akash , Pradhan Manik
Published: February 2024

We report on an experimental investigation of the Goos–Hänchen (GH) optical beam shift in the vicinity of the critical angle of incidence at an air–glass interface using a weak value amplification (WVA) technique for two mutually orthogonal first order Hermite–Gaussian (HG) modes (HG10 and HG01) of a light beam at 633 nm generated by a phase-only reflective spatial light modulator. We have developed a mathematical approach to visualize the beam shaping due to the WVA scheme of beam shifts for the HG modes. The study reveals the angle of incidence dependency of the GH shift in the total internal reflection condition. For both modes, a detailed study of the horizontal and transverse beam shift values with varied post-selection angles is also reported. In addition, a comparison of the beam shift values for both of the selected modes with the fundamental mode (HG00) has been demonstrated. We found a significant enhancement (about two to three times) in the beam shifts for the first order HG10 and HG01 modes compared to the fundamental mode (HG00). Our results clearly demonstrate the advantages of the HG modes of the light beam-exploiting WVA technique and thus may contribute significantly to this field and open up important applications in photonic manipulation and future technologies.
Enhancing unsteady heat transfer simulation in porous media through the application of convolutional neural networks
Authors: Saraireh Mohammad
Published: February 2024

This research describes a novel technique for anticipating unstable heat transfer in porous media. Convolutional neural networks (CNNs) are used with finite volume method (FVM) and long short-term memory (LSTM) networks to accomplish this. Heat transport networks are difficult to characterise using traditional numerical methodologies owing to their nonlinearity and complexity. The proposed solution combines FVM’s precise physical modelling with CNN’s and LSTM’s superior pattern identification and temporal analysis. This collaboration supports the suggested strategy. Heat transport dynamics simulations in porous materials are more accurate, efficient, and adaptable when employing this hybrid framework. The experimental setup focused on porous material properties and gathered and processed a large amount of data. The building’s three-dimensional shape, heat transfer, and time were investigated. Temporal fluctuations were also used. Multiple indicators are used to evaluate the overall performance of the model. These criteria include convergence speed, F1 score, accuracy, precision, recall, and computational cost. In the most notable numerical results, the proposed strategy surpasses both the Finite Element and the Lattice Boltzmann methods. The presented method enabled fast convergence and reduced processing costs. These results were: accuracy (0.92), precision (0.93), recall (0.91), and F1 score (0.92). The proposed method is generalizable and adaptable, and it can address a variety of heat transport simulation problems in porous media. Unlike CNNs, which can identify significant spatial patterns, LSTM cells can only see temporal dynamics. These two components are required to show heat transfer, which is a continually changing phenomenon. Modern technology enables more complex simulations. Processing expenses are lowered, and estimations are more accurate. These two discoveries were obtained through the inquiry and methodologies. Finally, the CNN-FVM-LSTM technique simulates heat transport using complicated computer models. Predicting unusually high temperatures in porous materials may improve the model’s accuracy, computational efficiency, and flexibility.
Limiting the Use of Force
Authors: Edelman R David
Published: February 2024

Considering the role that positive international law has on present-day and future cyberattack decision-making, Chapter 5 begins by orienting the reader to the jus ad bellum and arguing that based on its bedrock status within international law and absent more specialized regimes covering cyberattacks, the UN Charter regime is the right starting point in considering international law’s potential for restraint. Part III explores the contours and present debates over what defines prohibited uses of force. Engaging with the evolving literature on these questions both generally and in the context of cyberattacks, it offers several ways through an historical analytical thicket surrounding the UN Charter’s Article 2(4) to clarify how cyberattacks are, indeed, prohibited uses of force. It then argues that though this conclusion has growing support within the literature, states are still left with a key gap in their cyberattack decision-making: the consequences for a violation of this debatable limit. This, it argues, is the most significant remaining question in evaluating regulative restraint of cyberattacks, and predictably, the most contested among states. It concludes that the practical ambiguities here are likely to overwhelm even Article 2(4)’s universally recognized status. The need is to understand how states might bridge the gap between illegality and corrective action; in essence, whether the remedial jus ad bellum will durably activate to restrain states’ adversaries or themselves.
Constructing a Prohibition
Authors: Edelman R David
Published: February 2024

Chapter 8 argues that, properly scoped, this logic provides ample basis for a certain kind of prohibitive norm, if not a formal regime keeping a check on that restraint. It begins by asking the question of why, in light of the foregoing, conventional wisdom has dismissed the sort prohibitions on cyberattacks that exist for chemical or biological weapons. The chapter then draws together the arguments of those preceding it to confirm that while usability has been the defining competition among states for the last two decades, a deeper look into the logics of states’ cyberattack policies reveals a parallel process called structural prohibition that is also underway. The result, it argues, is the strongest potential for cyberattack restraint: a novel, narrowly focused humanitarian norm against cyberattacks—appealing equally and sequentially to states’ constitutive, regulative, and rationalist logics of restraint.
Branching out: perch diameter and orientation affect pull strength in chameleons (genus: Bradypodion)
Authors: Herrel Anthony , Taft Jody M , Main Devon C , da Silva Jessica M , Tolley Krystal A
Published: February 2024

Arboreal species tend to have specific adaptations allowing them to effectively negotiate the complexity of their habitats. For example, chameleons have a prehensile tail and limbs adapted to grasping branches. However, the impact of branch diameter and orientation on their movement has been poorly studied. Using ecological, morphological, and pull force data from two species of Bradypodion from different habitats, we examined if chameleons use different substrates and if perch orientation and diameter affect pull strength by quantifying their grip forces on different sized dowels. We found that the habitat of Bradypodion ventrale is homogeneous, and dominated by sparse patches of narrow, vertical perches. For this species, perch diameter significantly affected pull strength in both horizontal and vertical pull directions, with chameleons performing best on a vertical 1.5-mm dowel and a horizontal 3-mm dowel. In contrast, Bradypodion pumilum typically occurs in more variable vegetation, ranging from low shrubs to wooded habitat with high canopy. Our results show that the habitat has perches that are on average wider than for B. ventrale with a greater size range. The performance of B. pumilum was less impacted by perch diameter and pull direction suggesting that B. pumilum is able to use perches of different diameters in their more heterogeneous habitat.
Vocalizations and species limits in the North Atlantic clade of small shearwaters (Procellariiformes: Puffinus)
Authors: Sangster George , Robb Magnus S , Mackin William A , Bolton Mark
Published: February 2024

Species limits in the North Atlantic clade of small shearwaters (Puffinus lherminieri lherminieri, P. l. baroli, and P. l. boydi) have been controversial. In this study, the aerial calls of P. l. boydi are described in detail and compared with those of P. l. baroli and P. l. lherminieri. Multivariate methods were used to test for differences in seven characteristics of aerial calls among the three taxonomic groups, in a sample of 135 individuals. There were differences between males and females in five of the seven call elements studied and differences in all seven call elements among the three taxonomic groups. Discriminant function analysis provided a high degree of discrimination, with 91%–100% of the calls being assigned to the correct taxon. The overall level of acoustic differentiation between P. l. baroli and P. l. boydi was similar to that between P. l. baroli and P. l. lherminieri and twice as high as that of P. l. boydi and P. l. lherminieri. These acoustic data, in combination with previously reported patterns of morphometric and molecular divergence, support the recognition of three North Atlantic species: P. lherminieri, P. baroli, and P. boydi. This study underscores that patterns of acoustic variation provide a useful source of information for taxonomic studies of procellariiform seabirds.
Social associations are predicted by nest proximity but not kinship in a free-living social parrot
Authors: Dawson Pell Francesca S E , Hatchwell Ben J , Ortega-Segalerva Alba , Senar Juan Carlos
Published: February 2024

Social associations among conspecifics are typically non-random, often being a function of relatedness, familiarity, or spatial distributions. The aim of this study was to combine field observations with molecular genetic techniques and social network analysis to investigate the predictors of social associations in free-living monk parakeets, Myiopsitta monachus. Monk parakeets are non-territorial parrots whose nests are often aggregated, with relatives clustered in kin neighbourhoods and within cooperatively breeding groups. First, we characterized social associations when away from the nest, showing that individuals typically had a few strong social ties. Second, we investigated whether these social associations were related to nest proximity or genetic relatedness. The strength of association decreased with increasing inter-nest distance, but there was negligible influence of relatedness on the strength of associations. These patterns did not differ between same-sex and opposite-sex dyads. Finally, we investigated whether members of breeding pairs were close social associates, finding that in most cases the closest associate of an individual was their mate, although social bonds also existed outside of the pair; members of breeding groups also associated closely when foraging. Social associations are poorly known in parrots owing to methodological challenges, hence our results add to the limited knowledge of sociality in this taxon.
Safe Staffing and Workload Management in Social Work: A Scoping Review of Legislation, Policy and Practice
Authors: McFadden Paula , Davies Hannah , Manthorpe Jill , MacLochlainn Justin , McGrory Susan , Naylor Rachel , Mallett John , Kirby Karen , Currie Denise , Schroder Heike , Nicholl Patricia , Mullineux Judith , McColgan Mary
Published: February 2024

In Northern Ireland, social work-specific legislation is planned for safe staffing across the governmental sector. As part of a broader research project to inform this development, we conducted a scoping review seeking examples of safe staffing definitions, safe staffing-related legislation, policy and practice in social work and associated professions from the UK and internationally. We searched English language databases in 2023 websites and reference lists as well as grey literature. Finding no international examples of social work-specific safe staffing definitions, legislation, or policy outside of Children’s Services, we offer a tentative definition to the current debate. Our scoping review found examples of individual social workers and local teams developing caseload management practices to promote ‘safer’ working, which may be useful for policymakers and regulators to consider. However, these need greater conceptual clarity, consensus over definitions and outcomes, and evaluation for cost-effectiveness. Given the limited evidence in this area, recommendations include the need for further research to ascertain what ‘safe staffing’ does, can and should mean in social work and what can work in different contexts and at different levels of policy and practice to inform service user and social worker safety in social work.
Integration of diffusion tensor imaging parameters with mesh morphing for in-depth analysis of brain white matter fibre tracts
Authors: Tayebi Maryam , Kwon Eryn , Maller Jerome , McGeown Josh , Scadeng Miriam , Qiao Miao , Wang Alan , Nielsen Poul , Fernandez Justin , Holdsworth Samantha , Shim Vickie ,   Matai mTBI Research Group, Potter Leigh , Condron Paul , Taylor Davidson , Cornfield Daniel , McHugh Patrick , Emsden Taylor , Danesh-Meyer Helen , Newburn Gil , Bydder Graeme
Published: February 2024

Averaging is commonly used for data reduction/aggregation to analyse high-dimensional MRI data, but this often leads to information loss. To address this issue, we developed a novel technique that integrates diffusion tensor metrics along the whole volume of the fibre bundle using a 3D mesh-morphing technique coupled with principal component analysis for delineating case and control groups. Brain diffusion tensor MRI scans of high school rugby union players (n = 30, age 16–18) were acquired on a 3 T MRI before and after the sports season. A non-contact sport athlete cohort with matching demographics (n = 12) was also scanned. The utility of the new method in detecting differences in diffusion tensor metrics of the right corticospinal tract between contact and non-contact sport athletes was explored. The first step was to run automated tractography on each subject’s native space. A template model of the right corticospinal tract was generated and morphed into each subject’s native shape and space, matching individual geometry and diffusion metric distributions with minimal information loss. The common dimension of the 20 480 diffusion metrics allowed further data aggregation using principal component analysis to cluster the case and control groups as well as visualization of diffusion metric statistics (mean, ±2 SD). Our approach of analysing the whole volume of white matter tracts led to a clear delineation between the rugby and control cohort, which was not possible with the traditional averaging method. Moreover, our approach accounts for the individual subject’s variations in diffusion tensor metrics to visualize group differences in quantitative MR data. This approach may benefit future prediction models based on other quantitative MRI methods.
Impaired cognitive flexibility and disrupted cognitive cerebellum in degenerative cerebellar ataxias
Authors: Shin Jung Hwan , Kim Heejung , Lee So Yeon , Yoon Won Tae , Park Sun-Won , Park Sangmin , Yoo Dallah , Lee Jee-Young
Published: February 2024

There is a clinically unmet need for a neuropsychological tool that reflects the pathophysiology of cognitive dysfunction in cerebellar degeneration. We investigated cognitive flexibility in degenerative cerebellar ataxia patients and aim to identify the pathophysiological correlates of cognitive dysfunction in relation to cerebellar cognitive circuits. We prospectively enrolled degenerative cerebellar ataxia patients with age-matched healthy controls who underwent 3 T 3D and resting-state functional MRI. All 56 participants were evaluated with the Scale for Assessment and Rating of Ataxia and neuropsychological tests including the Wisconsin Card Sorting Test, Trail Making Test, Montreal Cognitive Assessment and Mini-Mental State Examination. From MRI scans, we analysed the correlation of whole-brain volume and cortico–cerebellar functional connectivity with the Wisconsin Card Sorting Test performances. A total of 52 participants (29 ataxia patients and 23 healthy controls) were enrolled in this study. The Wisconsin Card Sorting Test scores (total error percentage, perseverative error percentage, non-perseverative error percentage and categories completed), Trail Making Test A and Montreal Cognitive Assessment were significantly impaired in ataxia patients (P < 0.05) compared to age-matched healthy controls. The Wisconsin Card Sorting Test error scores showed a significant correlation with the ataxia score (P < 0.05) controlling for age and sex. In volumetric analysis, the cerebellar right crus I, II, VIIb and VIII atrophy correlated with non-perseverative error percentage in the ataxia group. In functional connectivity analysis, the connectivity between crus I, II and VIIb of the cerebellum and bilateral superior parietal and superior temporal gyrus was significantly altered in ataxia patients. The functional connectivity between left crus II and VIIb of the cerebellum and dorsolateral prefrontal and superior frontal/parietal cortices showed a positive correlation with perseverative error percentage. The connectivity between left crus VIIb and pontine nucleus/middle cerebellar peduncle showed a significant negative correlation with non-perseverative error percentage in the ataxia group. The impaired cognitive flexibility represented by the Wisconsin Card Sorting Test was significantly impaired in degenerative cerebellar ataxia patients and correlated with disease severity. The Wisconsin Card Sorting Test performance reflects hypoactivity of the cognitive cerebellum and disrupted cortico–cerebellar connectivity in non-demented patients with degenerative cerebellar ataxia.
Diagnostic errors during perceptual learning in dermatology: a prospective cohort study of Finnish undergraduate students
Authors: Salava Alexander , Salmela Viljami
Published: February 2024

Background

Perceptual learning modules (PLMs) have been shown to significantly improve learning outcomes in teaching dermatology.

Objectives

To investigate the quantity and quality of diagnostic errors made during undergraduate PLMs and their potential implications.

Methods

The study data were acquired from 8 successive dermatology courses (2021–23) from 142 undergraduate medical students. Digital PLMs were held before, during and after the courses. We investigated the number and distribution of diagnostic errors, differences between specific skin conditions and classified the errors based on type.

Results

Diagnostic errors were not randomly distributed. Some skin conditions were almost always correctly identified, whereas a significant number of errors were made for other diagnoses. Errors were classified into one of three groups: mostly systematic errors of relevant differential diagnoses (‘similarity’ errors); partly systematic errors (‘mixed’ errors); and ‘random’ errors. While a significant learning effect during the repeated measures was found in accuracy (P < 0.001, η²P = 0.64), confidence (P < 0.001, η²P = 0.60) and fluency (P < 0.001, η²P = 0.16), the three categories differed in all outcome measures (all P < 0.001, all η²P > 0.47). Visual learning was more difficult for diagnoses in the similarity category (all P < 0.001, all η²P > 0.12) than for those in the mixed and random categories.

Conclusions

Error analysis of PLMs provided relevant information about learning efficacy and progression, and systematic errors in tasks and more difficult-to-learn conditions. This information could be used in the development of adaptive, individual error-based PLMs to improve learning outcomes, both in dermatology and medical education in general.
The balance between memory and regulatory cell populations in kidney transplant recipients with operational tolerance
Authors: Süsal Caner , Alvarez Cristiam M , Benning Louise , Daniel Volker , Zeier Martin , Schaier Matthias , Morath Christian , Speer Claudius
Published: February 2024

Donor-reactive memory cells represent a barrier to long-term kidney graft survival. A better understanding of regulatory mechanisms that counterbalance alloreactive memory responses may help to identify patients with operational tolerance. This prospective study investigated the equilibrium between memory T-cell subsets and regulatory T or B cells (Tregs, Bregs) in peripheral blood of kidney transplant recipients with operational tolerance (N = 8), chronic rejection (N = 8), and different immunosuppressive treatment regimens (N = 81). Patients on hemodialysis and healthy individuals served as controls (N = 50). In addition, the expression of Treg- and Breg-associated molecule genes was analyzed. Patients with chronic rejection showed a disrupted memory T-cell composition with a significantly higher frequency of circulating CD8+ terminally differentiated effector memory (TEMRA) T cells than patients with operational tolerance, patients on hemodialysis, or healthy controls (P < 0.001). Low frequency of CD8+ TEMRA and high frequency of Tregs and transitional Bregs were found in operationally tolerant patients. Consequently, operationally tolerant patients showed, as compared to all other transplant recipients with different immunosuppressive regiments, the lowest ratios between CD8+ TEMRA T cells and Tregs or Bregs (for both P < 0.001). Moreover, a specific peripheral blood transcription pattern was found in operationally tolerant patients with an increased expression of Breg- and Treg-associated genes CD22 and FoxP3 and a decreased FcγRIIA/FcγRIIB transcript ratio (for all P < 0.001). In conclusion, monitoring the balance between circulating CD8+ TEMRA T cells and regulatory cell subsets and their transcripts may help to distinguish transplant recipients with operational tolerance from recipients at risk of graft loss.
On-surface smooth polymerization of 5,11-bianthryl-anthradithiophene
Authors: Kasahara Shoma , Ohtomo Manabu , Hayashi Ryunosuke , Fushimi Naoki , Yamaguchi Junichi , Matsuo Kyohei , Aratani Naoki , Sato Shintaro , Hayashi Hironobu , Yamada Hiroko
Published: February 2024

An anthracene trimer comprising an anthradithiophene central unit has been successfully synthesized and its structure was confirmed by using single-crystal X-ray analysis. The surface-assisted reaction of the trimer on Au(111) under ultra-high vacuum conditions provided a long 5,11-bianthryl-anthradithiophene polymer with its length of more than 90 nm, owing to the efficient diffusion of the trimer on the Au(111) surface.
Targeting Tularemia: Clinical, Laboratory, and Treatment Outcomes From an 11-year Retrospective Observational Cohort in Northern Sweden
Authors: Plymoth Martin , Lundqvist Robert , Nystedt Anders , Sjöstedt Anders , Gustafsson Tomas N
Published: February 2024

Background

Tularemia is an important reemerging disease with a multimodal transmission pattern. Treatment outcomes of current recommended antibiotic regimens (including ciprofloxacin and doxycycline) remain unclear. In this retrospective cohort study, we report clinical, laboratory, geographical, and treatment outcomes of laboratory-confirmed tularemia cases over an 11-year period in Northern Sweden.

Methods

Data from reported tularemia cases (aged >10 years at time of study) in Norrbotten county between 2011 and 2021 were collected through review of electronic medical records and participant questionnaires; 415 of 784 accepted participation (52.9%). Of these, 327 were laboratory-confirmed cases (serology and/or polymerase chain reaction). A multivariable logistic regression model was used to investigate variables associated with retreatment.

Results

Median age of participants was 54 years (interquartile range [IQR], 41.5–65) and 49.2% were female. Although ulceroglandular tularemia was the predominant form (n = 215, 65.7%), there were several cases of pulmonary tularemia (n = 40; 12.2%). Inflammatory markers were largely nonspecific, with monocytosis frequently observed (n = 36/75; 48%). Tularemia was often misdiagnosed on presentation (n = 158, 48.3%), with 65 (19.9%) receiving initial inappropriate antibiotics and 102 (31.2%) retreated. Persistent lymphadenopathy was infrequent (n = 22, 6.7%), with 10 undergoing surgical interventions. In multivariable analysis of variables associated with retreatment, we highlight differences in time until receiving appropriate antibiotics (8 [IQR, 3.25–20.75] vs 7 [IQR, 4–11.25] days; adjusted P = .076), and doxycycline-based treatment regimen (vs ciprofloxacin; adjusted P = .084), although this was not significant after correction for multiple comparisons.

Conclusions

We comprehensively summarize clinical, laboratory, and treatment outcomes of type B tularemia. Targeting tularemia requires clinical awareness, early diagnosis, and timely commencement of treatment for an appropriate duration.
Effect of urine alkalization on urinary inflammatory markers in cystinuric patients
Authors: Prot-Bertoye Caroline , Jung Vincent , Tostivint Isabelle , Roger Kevin , Benoist Jean-François , Jannot Anne-Sophie , Van Straaten Alexis , Knebelmann Bertrand , Guerrera Ida Chiara , Courbebaisse Marie
Published: February 2024

Background

Cystinuria is associated with a high prevalence of chronic kidney disease (CKD). We previously described a urinary inflammatory-protein signature (UIS), including 38 upregulated proteins, in cystinuric patients (Cys-patients), compared with healthy controls (HC). This UIS was higher in Cys-patients with CKD. In the present observational study, we aimed to investigate the UIS in Cys-patients without CKD and patients with calcium nephrolithiasis (Lith-patients), versus HC and the effect of urine alkalization on the UIS of Cys-patients.

Methods

UIS was evaluated by nano-liquid chromatography coupled to high-resolution mass spectrometry in adult HC, Lith-patients and non-treated Cys-patients with an estimated glomerular filtration rate >60 mL/min/1.73 m2, and after a 3-month conventional alkalizing treatment in Cys-patients.

Results

Twenty-one Cys-patients [12 men, median age (interquartile range) 30.0 (25.0–44.0) years], 12 Lith-patients [8 men, 46.2 (39.5–54.2) years] and 7 HC [2 men, 43.1 (31.0–53.9) years] were included. Among the 38 proteins upregulated in our previous work, 11 proteins were also upregulated in Cys-patients compared with HC in this study (5 circulating inflammatory proteins and 6 neutrophil-derived proteins). This UIS was also found in some Lith-patients. Using this UIS, we identified two subclusters of Cys-patients (5 with a very high/high UIS and 16 with a moderate/low UIS). In the Cys-patients with very high/high UIS, urine alkalization induced a significant decrease in urinary neutrophil-derived proteins.

Conclusion

A high UIS is present in some Cys-patients without CKD and decreases under alkalizing treatment. This UIS could be a prognostic marker to predict the evolution towards CKD in cystinuria.
Cardiac and perivascular myofibroblasts, matrifibrocytes, and immune fibrocytes in hypertension; commonalities and differences with other cardiovascular diseases
Authors: Torimoto Keiichi , Elliott Katherine , Nakayama Yuki , Yanagisawa Hiromi , Eguchi Satoru
Published: February 2024

Hypertension is a major cause of cardiovascular diseases such as myocardial infarction and stroke. Cardiovascular fibrosis occurs with hypertension and contributes to vascular resistance, aortic stiffness, and cardiac hypertrophy. However, the molecular mechanisms leading to fibroblast activation in hypertension remain largely unknown. There are two types of fibrosis: replacement fibrosis and reactive fibrosis. Replacement fibrosis occurs in response to the loss of viable tissue to form a scar. Reactive fibrosis occurs in response to an increase in mechanical and neurohormonal stress. Although both types of fibrosis are considered adaptive processes, they become maladaptive when the tissue loss is too large, or the stress persists. Myofibroblasts represent a subpopulation of activated fibroblasts that have gained contractile function to promote wound healing. Therefore, myofibroblasts are a critical cell type that promotes replacement fibrosis. Although myofibroblasts were recognized as the fibroblasts participating in reactive fibrosis, recent experimental evidence indicated there are distinct fibroblast populations in cardiovascular reactive fibrosis. Accordingly, we will discuss the updated definition of fibroblast subpopulations, the regulatory mechanisms, and their potential roles in cardiovascular pathophysiology utilizing new knowledge from various lineage tracing and single-cell RNA sequencing studies. Among the fibroblast subpopulations, we will highlight the novel roles of matrifibrocytes and immune fibrocytes in cardiovascular fibrosis including experimental models of hypertension, pressure overload, myocardial infarction, atherosclerosis, aortic aneurysm, and nephrosclerosis. Exploration into the molecular mechanisms involved in the differentiation and activation of those fibroblast subpopulations may lead to novel treatments for end-organ damage associated with hypertension and other cardiovascular diseases.
Ventricular arrhythmias and haemodynamic collapse during acute coronary syndrome: increased risk for sudden cardiac death?
Authors: Järvensivu-Koivunen Minna , Tynkkynen Juho , Oksala Niku , Eskola Markku , Hernesniemi Jussi
Published: February 2024

Aims

In the acute phase of acute coronary syndrome (ACS), ventricular tachycardia (VT) and/or ventricular fibrillation (VF) leading to resuscitation are not considered to be associated with increased long-term sudden cardiac death (SCD) because the cause—acute ischaemia—is believed to be reversible. The aim of this study is to investigate whether ventricular arrhythmias (VAs) leading to sudden cardiac arrest during ACS are associated with the risk of incident SCD in patients with a normal or mildly impaired left ventricular ejection fraction (LVEF).

Methods and results

This study is based on a retrospective analysis of all 8062 consecutive ACS patients undergoing coronary angiography with the baseline LVEF ≥40% between 2007 and 2018 (follow-up until 31 December 2021). The primary outcome was SCD-equivalent life-threatening VAs (LTVAs) composed of true SCDs and SCDs aborted by successful resuscitation or appropriate implantable cardiac device (ICD) therapy. The risk of sudden LTVA was estimated with a multivariate subdistribution hazard model using other deaths as competing events. Two-hundred thirteen (n = 211, 2.6%) patients suffered acute phase VF/VT leading to resuscitation and survived to discharge, and most occurred before angiography (80.6%, n = 170) and were VF (92.9%, n = 196). During a median follow-up of 7.6 years, 3.9% (n = 316) of all the patients had LTVA (10.0% in the VF/VT group vs. 3.8% in other patients). Ventricular fibrillation/VTs during ACS are associated with an increased risk for future SCD (hazard ratio 3.07; 95% confidence interval 1.94–4.85, P < 0.001). Most LTVAs occurred in patients without ICDs.

Conclusion

Ventricular fibrillation/VT in ACS is associated with a remarkably high long-term risk for SCD in patients with an LVEF ≥40%.
Prognostic significance of aortic valve calcification in relation to coronary artery calcification for cardiovascular diseases
Authors: Wen Han , Huang Rihua , Xu Xinghao , Xiong Zhenyu , Liu Menghui , Guo Yue , Zhuang Xiaodong , Liao Xinxue
Published: February 2024

Aims

Both coronary artery calcification (CAC) and aortic valve calcification (AVC) are strongly associated with cardiovascular diseases (CVDs), but data about the prognostic significance of multiple cardiovascular calcifications are limited. We aim to investigate the interaction relationship between AVC and CAC for major events.

Methods and results

We included 6695 participants from the Multi-Ethnic Study of Atherosclerosis at baseline and divided them into four groups: (i) no AVC or CAC; (ii) only AVC; (iii) only CAC; and (iv) with CAC and CAC. The Cox regression model and the Kaplan–Meier method were used to analyse CVD outcomes. We evaluated the interaction between AVC and CAC and their added predictive value based on the pooled cohort equations (PCEs). Subgroup analyses were also explored. Among 6695 participants (mean age 62.2 ± 10.2 years, 47.2% male), after follow-up, 943 cases (14.1%) of CVD and 1274 cases (19.0%) of all-cause death occurred. For participants with both AVC and CAC, the risk of CVD significantly increased [hazard ratio = 3.43 (2.69–4.37), P < 0.001], even higher than the sum of the ones with only AVC and only CAC. This trend remained the same for all-cause death and among subgroup analyses. The addictive interaction was statistically significant (P < 0.001). When AVC and CAC were added, the predictive value of PCEs increased.

Conclusion

Our results indicated a synergistic interaction between valve calcification and coronary calcification in CVDs. Management for both AVC and CAC may bring health co-benefits in preventing poor outcomes.