bluuebunny/crossref_metadata_2025 huggingface dataset:
Arterial input function estimation compensating for inflow and partial voluming in dynamic contrast‐enhanced MRI
Authors: Tseng Chih‐Hsien , Nagtegaal Martijn A. , van Osch Matthias J.P. , Jaspers Jaap , Mendez Romero Alejandra , Wielopolski Piotr , Smits Marion , Vos Frans M.
Published: August 2024

Both inflow and the partial volume effect (PVE) are sources of error when measuring the arterial input function (AIF) in dynamic contrast‐enhanced (DCE) MRI. This is relevant, as errors in the AIF can propagate into pharmacokinetic parameter estimations from the DCE data. A method was introduced for flow correction by estimating and compensating the number of the perceived pulse of spins during inflow. We hypothesized that the PVE has an impact on concentration–time curves similar to inflow. Therefore, we aimed to study the efficiency of this method to compensate for both effects simultaneously. We first simulated an AIF with different levels of inflow and PVE contamination. The peak, full width at half‐maximum (FWHM), and area under curve (AUC) of the reconstructed AIFs were compared with the true (simulated) AIF. In clinical data, the PVE was included in AIFs artificially by averaging the signal in voxels surrounding a manually selected point in an artery. Subsequently, the artificial partial volume AIFs were corrected and compared with the AIF from the selected point. Additionally, corrected AIFs from the internal carotid artery (ICA), the middle cerebral artery (MCA), and the venous output function (VOF) estimated from the superior sagittal sinus (SSS) were compared. As such, we aimed to investigate the effectiveness of the correction method with different levels of inflow and PVE in clinical data. The simulation data demonstrated that the corrected AIFs had only marginal bias in peak value, FWHM, and AUC. Also, the algorithm yielded highly correlated reconstructed curves over increasingly larger neighbourhoods surrounding selected arterial points in clinical data. Furthermore, AIFs measured from the ICA and MCA produced similar peak height and FWHM, whereas a significantly larger peak and lower FWHM was found compared with the VOF. Our findings indicate that the proposed method has high potential to compensate for PVE and inflow simultaneously. The corrected AIFs could thereby provide a stable input source for DCE analysis.
Nitrogen sources in donor human milk: True protein, nonprotein nitrogen, and amino acid profile
Authors: Stansfield Brian K. , Gates Amy
Published: August 2024

Background

Devices measuring the macronutrient content of human milk are commonly used to assist with clinical decision‐making. It is unknown if these devices accurately measure protein content in donor human milk (DHM). Our objective is to quantify the nitrogen sources and protein content in commercial DHM.

Methods

The total nitrogen content (Dumas method) and nonprotein nitrogen content (Kjeldahl method) was measured in triplicate from six commercial DHM samples with protein content noted on the labels. In addition, the amino acid content was measured in 15 commercial DHM samples and protein content in each sample was calculated. The calculated protein content for each DHM sample was compared for consistency.

Results

The nonprotein nitrogen content in DHM was consistently higher (0.33 ± 0.05 g/g) than previous reports, leading to overreporting of protein content on DHM labels by a median value of 0.15 g/dl (range 0.02–0.23 g/dl). Similarly, calculation of the protein content from the total nitrogen content with an assumption of 20% (grams per gram) nonprotein nitrogen consistently overrepresented the protein content as determined from the amino acid profile for DHM.

Conclusion

Common methods for assessing the macronutrient content of human milk may overestimate the protein content of DHM.
Accurate bidiagonal decompositions of Cauchy–Vandermonde matrices of any rank
Authors: Delgado Jorge , Koev Plamen , Marco Ana , Martínez José‐Javier , Peña Juan Manuel , Persson Per‐Olof , Spasov Steven
Published: August 2024

We present a new decomposition of a Cauchy–Vandermonde matrix as a product of bidiagonal matrices which, unlike its existing bidiagonal decompositions, is now valid for a matrix of any rank. The new decompositions are insusceptible to the phenomenon known as subtractive cancellation in floating point arithmetic and are thus computable to high relative accuracy. In turn, other accurate matrix computations are also possible with these matrices, such as eigenvalue computation amongst others.
Activating the Vā: Performance, Academia and the Sublime — Association for Social Anthropology in Oceania (ASAO) 2023 Distinguished Lecture
Authors: Hereniko Vilsoni
Published: August 2024

The concept of vā in various Oceanic cultures came into academic discourse among Pacific Islands scholars in the mid‐1990s, but it was not until covid became a global pandemic and an academic conference focusing solely on the vā took place in 2021 that the concept became a focus of my interest. This is partly because certain rules of behavior such as ‘social distancing’ drew attention to the importance of the ‘space between’ individuals as well as the space between humans and the natural world. What exactly does vā mean and why is it so important to understand its potential? How does the concept of vā apply to culture in relation to performance, specifically the genre of dance? What about academic writing, which does not exist in a three‐dimensional space? As a creative artist and scholar, I am interested in how to activate the vā in both arenas so that the quality of the outcome that results from this activation is elevated to the level of the sublime.
Current Demography and Treatment Strategy of Vestibular Migraine in Neurotologic Perspective
Authors: Lin Kuei‐You , Rauch Steven D.
Published: August 2024

Objective

This study aims to describe the demographic features of vestibular migraine (VM) compared to other common peripheral vestibulopathies, and to assess the efficacy of trigger management as primary VM treatment.

Study Design

Retrospective study.

Setting

Tertiary referral medical center.

Methods

A retrospective chart review was performed of patients presenting with dizziness in a tertiary neurotology clinic. Among the newly diagnosed dizzy patients, those with a diagnosis of either VM, Ménière's disease, benign paroxysmal positional vertigo, or vestibular neuritis/labyrinthitis were selected for comparisons of the disease demographics. VM patients with multiple clinic visits in the study period were included for the treatment strategy analysis.

Results

A total of 1285 patients met the study inclusion criteria. In the newly diagnosed dizzy group comprising 814 patients, VM patients accounted for the largest (25%) and youngest (mean age 47 years) cohort, showing an obvious female preponderance of approximately 3.3:1. Furthermore, prevalence of VM declined significantly with advancing age, from 69%, to 34%, to 11%, in age groups of ≤30, 31 to 60, and >60 years, respectively. Trigger management, when employed as the primary VM first‐year treatment, was effective for both sexes. Notably, it was more effective for women aged over than under 45 years.

Conclusion

In our tertiary referral neurotologic center, VM was the most common diagnosis in newly diagnosed dizzy patients aged under 60 years, especially in women. For primary VM treatment, trigger management is an effective option deserving consideration.
Facile preparation and performance of flexible sensors based on polyacrylamide/carboxymethylchitosan/tannin acid hydrogels
Authors: Liu Haochen , Huang Bei , Ke Guipin , Cao Zheng , Cheng Junfeng , Wang Dong , Sun Fangli , Ma Wenzhong , Liu Chunlin
Published: August 2024

Hydrogel flexible sensors are gaining significant interest due to their distinct biocompatibility, flexibility, and unique features of being adjustable and injectable, but there are still problems of poor self‐healing performance and low conductivity in the current stage of research. In this work, a prefabricated blending method was used to construct a dual‐network system using polyacrylamide (PAM), carboxymethyl chitosan (CMCS), and tannin acid (TA), and ferric ions (Fe3+) were introduced to apply ionically conductive organic hydrogels to flexible sensors. The PAM/CMCS‐Fe3+/TA hydrogels have good fatigue resistance and self‐healing properties, and their conductivity is as high as 6.42 S/m. This hydrogel‐based sensor for strain sensing purpose offers a lot of promise for flexible sensor applications since it can provide steady, dependable, and repeatable electrical impulses.
Detection of the epidemic Pseudomonas aeruginosa AUST‐03 (ST242) strain in people with cystic fibrosis in South Africa
Authors: Hamiwe Thabo , White Debbie A. , Kwenda Stanford , Ismail Arshad , Klugman Susan , Van Bruwaene Lore , Goga Ameena , Kock Marleen M. , Smith Anthony M. , Ehlers Marthie M.
Published: August 2024

Introduction

Pseudomonas aeruginosa AUST‐03 (ST242) has been reported to cause epidemics in people with CF (pwCF) from Australia and has been associated with multidrug resistance and increased morbidity and mortality. Here, we report an epidemic P. aeruginosa (AUST‐03) strain in South African pwCF detected at a public hospital and characterize the genomic antibiotic resistance determinants.

Methods

The P. aeruginosa AUST‐03 (ST242) study isolates were analysed with whole genome sequencing using the Illumina NextSeq2000 platform. Raw sequencing reads were processed using the Jekesa pipeline and multilocus sequence typing and genomic antibiotic resistance characterization was performed using public databases. Genetic relatedness between the study isolates and global P. aeruginosa ST242 from public databases was determined using a maximum‐likelihood phylogenetic tree. Antibiotic susceptibility testing was performed using the disk diffusion and broth microdilution techniques.

Results

A total of 11 P. aeruginosa AUST‐03 isolates were isolated from two children with CF. The majority (8/11) of these isolates were multidrug‐resistant (MDR) or extensively drug resistant; and the multidrug efflux pumps MexAB‐OprM, MexCD‐OprJ, MexEF‐OprN, and MexXY‐OprM were the most clinically relevant antibiotic resistance determinants and were detected in all of the isolates. The study isolates were the most closely related to a 2020 P. aeruginosa AUST‐03 (ST242) CF isolate from Russia.

Conclusion

Epidemic MDR P. aeruginosa strains are present at South African public CF clinics and need to be considered when implementing segregation and infection control strategies to prevent possible spread and outbreaks.
Families' perceptions of consumer‐grade, inexpensive oxygen saturation monitors
Authors: Charland Danielle , Kovesi Thomas
Published: August 2024

Objectives

We evaluated what proportion of families have a consumer‐grade pulse oximeter, why they bought one, and how they choose to use it.

Working Hypothesis

We hypothesized that children followed in cardiorespiratory clinics would be more likely to have an oximeter than children attending a more general clinic.

Study Design and Subject Selection

We carried out a cross‐sectional study using a convenience sample of children attending a respirology, cardiology, or gastroenterology clinic at a children's hospital. Consenting guardians completed a survey.

Results

Two‐hundred families completed the survey. Fifty‐three (26.5%; 53/200) had an oximeter at home. The proportion of children attending a cardiorespiratory clinic who had an oximeter was higher than another clinic (p = 0.08), but 15.5% of children attending the latter also had access to one. Of devices not funded by government insurance, over 80% of devices were “fingertip” clamp‐style oximeters, and 50% were purchased online. Most devices were used only when the child was ill (83.7%; 36/43). Only about 1/3 of families had received education about using an oximeter, and a similar proportion had compared their oximeter to a medical‐grade device. Only 2.4% (1/42) respondents did not feel that their device was “somewhat” or “very” accurate. The oxygen saturation that would prompt seeking emergency care was similar to most pediatric acute care guidelines.

Conclusions

Many children, particularly those with cardiorespiratory conditions, have access to consumer‐grade pulse oximeters. Asking about the presence of an oximeter should be part of the pediatric history, and families responding affirmatively should be offered education.
A stochastic constitutive model and its application to HTPB propellant
Authors: Zhou Dong‐Mo , Hui Bu‐Qing , Zhao Shao‐Bin , Chen Hang , Liu Xiang‐Yang
Published: August 2024

To address the issue of randomness in the mechanical properties of the hydroxyl‐terminated polybutadiene (HTPB) propellant, a stochastic constitutive model (SCM) with a lognormally distributed random parameter Λ was proposed to describe their mechanical behaviors, and the structural integrity of a HTPB propellant grain was analyzed based on it. The results indicate that the stress‐strain curves predicted by the SCM have a good agreement with the experimental curves, and the experimental curves fall within a 95 % probability interval predicted by the SCM. The mechanical response of HTPB propellant grain under ignition pressurization is associated with the random parameters Λ. The maximum equivalent stress and safety factor increase approximately linearly with the increase of random parameters Λ, while the maximum equivalent strain and maximum damage coefficient decrease approximately linearly with the increase of random parameters Λ. The error in the mechanical response of the grain obtained based on the SCM and the experimental constitutive model is basically not more than 2 %, the SCM can effectively characterize the randomness in the mechanical response of propellant grain caused by the dispersion of HTPB propellant mechanical properties.
Tutorial on Firth's Logistic Regression Models for Biomarkers in Preclinical Space
Authors: D'Angelo Gina , Ran Di
Published: August 2024

Preclinical studies are broad and can encompass cellular research, animal trials, and small human trials. Preclinical studies tend to be exploratory and have smaller datasets that often consist of biomarker data. Logistic regression is typically the model of choice for modeling a binary outcome with explanatory variables such as genetic, imaging, and clinical data. Small preclinical studies can have challenging data that may include a complete separation or quasi‐complete separation issue that will result in logistic regression inflated coefficient estimates and standard errors. Penalized regression approaches such as Firth's logistic regression are a solution to reduce the bias in the estimates. In this tutorial, a number of examples with separation (complete or quasi‐complete) are illustrated and the results from both logistic regression and Firth's logistic regression are compared to demonstrate the inflated estimates from the standard logistic regression model and bias‐reduction of the estimates from the penalized Firth's approach. R code and datasets are provided in the supplement.
Spectral scaling of unstably stratified atmospheric flows: Turbulence anisotropy and the low‐frequency spread
Authors: Charrondière Claudine , Stiperski Ivana
Published: August 2024

Unstable surface‐layer velocity and temperature spectra, scaled using inertial subrange properties and Monin–Obukhov similarity theory, have been known to show a notable spread in low frequencies. Here, a large ensemble of 14 datasets, over relatively simple (from flat and homogeneous terrain to gentle slopes or valley floor) and very complex mountainous terrain (steep slopes, crater rim, mountain tops), is used to assess the reasons for this low‐frequency behaviour. Turbulence anisotropy is shown to be the primary factor accounting for the spread in the spectral density at the largest scales and the spectral peak position of streamwise and spanwise velocity spectra. On the other hand, the low‐frequency behaviour of surface‐normal spectra is dominated by stability effects, whereas for temperature spectra turbulence anisotropy and stability play a similar role. Using a combination of scaling relations for temperature and velocity variances as well as dissipation of turbulence kinetic energy and half the temperature variance, and of a semi‐empirical model provided in the literature, we are able to describe the behaviour of the velocity and temperature spectra with only turbulence anisotropy and stability as input parameters. These observations are valid over both simple and complex mountainous terrain, although variability of the largest scales of complex‐terrain datasets highlights the effect of processes other than turbulence anisotropy or stability. Finally, we provide some insights into the scalewise nature of anisotropic eddies under different stabilities.
Large model biases in the Pacific centre of the Northern Annular Mode due to exaggerated variability of the Aleutian Low
Authors: Lee Simon H. , Polvani Lorenzo M.
Published: August 2024

The Northern Annular Mode (NAM) is traditionally defined as the leading empirical orthogonal function (EOF) of mean sea‐level pressure (MSLP) anomalies during winter. Previous studies have shown that the Pacific centre‐of‐action of the NAM is typically more amplified in models than in reanalysis. Here, we analyse the NAM in hindcasts from nine seasonal prediction models over 1993/1994–2016/2017. In all the models, the Pacific centre‐of‐action is much larger than in reanalysis over that period, during which the NAM and the North Atlantic Oscillation (NAO) are almost indistinguishable. As a result, the NAM in the models is correlated with Aleutian Low variability around four times more strongly than in reanalysis. We show that this discrepancy can be explained primarily by the amplitude of Aleutian Low variability, which is on average 17% higher in models than in reanalysis, with a secondary effect from a stronger correlation between the Aleutian Low and NAO. When the NAM is computed using zonally averaged MSLP, the Aleutian Low amplitude does not influence the pattern directly. Instead, the amplitude of the Pacific centre‐of‐action is governed primarily by the correlation between the Aleutian Low and NAO, reducing the apparent Pacific biases in models. While the two methods yield almost identical results in reanalysis, the large Aleutian Low biases result in differences when applied to model data. Modifying the MSLP statistically to alter the Aleutian Low amplitude reveals that the spatial pattern of the traditionally defined NAM is highly sensitive to Aleutian Low variability, even without modifying the correlation between the Aleutian Low and NAO. Hence, the NAM in models may not be as biased as the traditional method would suggest. We therefore conclude that the traditional EOF method is unsuitable for defining the NAM in the presence of highly amplified Aleutian Low variability, and encourage the use of the zonal‐mean method.
Underwater multizonotope terrain‐aided navigation method with coarse map based on set‐membership filter
Authors: Ma Dong , Ma Teng , Li Ye , Zhang Qiang , Ling Yu , Liao Yulei
Published: August 2024

Terrain‐aided navigation (TAN) is a viable method to achieve long‐term underwater navigation for long‐range autonomous underwater vehicles (AUVs). However, the high‐accuracy positioning results of most TAN systems rely on precise a priori seabed terrain maps, which restricts their applicability to a few areas with accurate bathymetric measurements of the seabed terrain. This article introduces a TAN system based on the General Bathymetric Chart of the Oceans (GEBCO) data set for global marine applications. Specifically, to address the low accuracy and poor robustness of the TAN system with imprecise bathymetric measurement and low‐resolution data from the GEBCO data set, this article proposes a multizonotope TAN method based on set‐membership filter (SMF) theory. The SMF theory is employed to handle the unknown distribution of the measurement noise from the GEBCO data set, introducing a multizonotope measurement update model to achieve more precise navigational results while addressing the perceptual ambiguity caused by self‐similar terrain. The smoothness of the terrain is incorporated as a parameter in the generation ranges of multizonotope, enabling adaptive adjustment based on terrain smoothness to reduce costs and enhance navigational performance. The accuracy and robustness of the proposed method are verified through all shipboard experiments, publicly available data sets, and AUV experiments. Compared with state‐of‐the‐art TAN methods, the average and maximum positioning errors have decreased by 64.83% and 48.84%, respectively. Finally, based on the experimental results, a preliminary distribution of suitable areas in the oceans is provided.
Temperature Dependent Growth Kinetics of Pd Nanocrystals: Insights from Liquid Cell Transmission Electron Microscopy
Authors: Lee Serin , Watanabe Tommy , Ross Frances M. , Park Jeung Hun
Published: August 2024

Quantifying the role of experimental parameters on the growth of metal nanocrystals is crucial when designing synthesis protocols that yield specific structures. Here, the effect of temperature on the growth kinetics of radiolytically‐formed branched palladium (Pd) nanocrystals is investigated by tracking their evolution using liquid cell transmission electron microscopy (TEM) and applying a temperature‐dependent radiolysis model. At early times, kinetics consistent with growth limited is measured by the surface reaction rate, and it is found that the growth rate increases with temperature. After a transition time, kinetics consistent with growth limited by Pd atom supply is measured, which depends on the diffusion rate of Pd ions and atoms and the formation rate of Pd atoms by reduction of Pd ions by hydrated electrons. Growth in this regime is not strongly temperature‐dependent, which is attributed to a balance between changes in the reducing agent concentration and the Pd ion diffusion rate. The observations suggest that branched rough surfaces, generally attributed to diffusion‐limited growth, can form under surface reaction‐limited kinetics. It is further shown that the combination of liquid cell TEM and radiolysis calculations can help identify the processes that determine crystal growth, with prospects for strategies for control during the synthesis of complex nanocrystals.
α‐CsPbI3 Quantum Dots ReRAM with High Air Stability Working by Valance Change Filamentary Mechanism
Authors: Lee Da Eun , Im In Hyuk , Baek Ji Hyun , Kwak Kyung Ju , Kim Seung Ju , Lee Tae Hyung , Kim Jae Young , Jang Ho Won
Published: August 2024

The current memory system is facing obstacles to improvement, and ReRAM is considered a powerful alternative. All‐inorganic α‐CsPbI3 perovskite‐based ReRAM working by electrochemical mechanism is reported, but the electrochemically active electrode raised difficulty in long‐term stable operation, and bulk α‐CsPbI3 device can not show resistive switching behavior with an inert metal top electrode. Herein, by making the α‐CsPbI3 into QDs and applying it to the device with inert Au as the top electrode, the devices working by valence change mechanism are successfully fabricated. The large surface‐to‐volume ratio made an abundant amount of iodine vacancies and facile migration of vacancies allowed the device to work by valence change mechanism. The devices show reliable electrical characteristics, 800 cycles endurance and retention for over 4 × 104 s, and air stability for 1 month. This work demonstrates that applying the QDs can improve the stability and enable a new type of working mechanism in ReRAM.
Dimensional Engineering in Efficient and Stable Inverted Perovskite Solar Cells
Authors: Zhu Qing , Yu Yue , Liu Xinxing , He Dongmei , Shai Xuxia , Feng Jing , Yi Jianhong , Chen Jiangzhao
Published: August 2024

Perovskite solar cells (PSCs) have attracted much attention in the field of photovoltaics, due to their high power conversion efficiency (PCE) and low cost. In recent years, inverted PSCs have achieved significant advancements in PCE and operational stability. Among the strategies for optimizing PCE and lifespan of inverted PSCs, dimensional engineering plays a critical role and garners increasing attention due to its versatile functions of passivating defects, releasing residual tensile stress, strengthening structural stability, ameliorating carrier transport and extraction, and so on. Considering the importance of dimensional engineering, a comprehensive and deep understanding of 2D perovskites and 2D/3D heterojunction is definitely necessary. In this review, first, the progress of low‐dimensional perovskite light‐harvesting materials in inverted PSCs is summarized. Subsequently, the advances in constructing 2D/3D perovskite heterojunctions, including 2D/3D bulk heterojunction within perovskite materials, 2D/3D interfacial heterojunction at the interface between perovskite film and carrier transport layer, and bottom‐up 2D/3D perovskite heterojunction are discussed. The simultaneous construction of 2D/3D heterojunction at dual interfaces is highlighted. Finally, the legitimate outlook on the further development of dimensional engineering is proposed to advance the commercialization of inverted photovoltaic technology.
Sonographic assessment of ulno‐humeral joint instability
Authors: Roche Bridie , Fenech Michelle
Published: August 2024

The ulnar collateral ligament (UCL) of the elbow plays a crucial role in elbow stability, specifically as a valgus and rotational constraint. Injuries to the UCL are common in overhead‐throwing athletes resulting in elbow instability. A timely diagnosis of early ulno‐humeral joint space widening in the overhead‐throwing athlete is required, to inform patient management and return to play. Sonographic assessment and measurement of the ulno‐humeral joint space with and without stress, and comparison to the contralateral uninjured side provides a quantitative assessment of instability. A systematic sonographic technique for single operator stress ultrasound is outlined to improve consistency of assessment and reporting of findings.
Anatomical study of pericardioperitoneal canal in immature beluga (Huso huso) with ultrasonography
Authors: Zehtabvar Omid , Vajhi AliReza , Masoudifard Majid , Davudypoor Somaye , Tonekabony Seyyed Hossein Modarres
Published: August 2024

Background

One of the special anatomical structures in sturgeons is the pericardioperitoneal canal (PPC), which has not been studied much. Considering that the presence and absence of this channel and its morphometry have not been investigated in this type of fish, this study was conducted.

Objective

The purpose of present study was to obtain a complete understanding about anatomical features and ultrasonography of PPC in the heart of immature beluga species in order to provide standard approaches for performing sonography and echocardiography on this sturgeon species.

Methods

Ten immature belugas (Huso huso) were used to perform ultrasonography with Sonosite MicroMaxx ultrasonography machine of ventral approach between two pectoral fins. After performing the steps of ultrasonographic study, gross anatomical studies were also performed, and the morphometric measurement of the canal was also performed.

Results

A small PPC was observed, which communicated between the pericardial cavity, and the peritoneal (coelomic) cavity. The cranial part of this channel, which was located immediately after the transverse septum, was on the midline of the body and was seen in midsagittal ultrasonograms. On average, the length of this canal was 3.23 ± 0.05 cm, and its diameter (cranial part) was 0.24 ± 0.04 cm.

Conclusions

In the present study on immature beluga, it was observed that the canal is located behind the sinus venosus and is caudoventral to it, though behind the transverse septum. It has been mentioned that this PPC establishes a connection between the pericardial cavity and the peritoneal cavity, so this connection is between the peritoneal cavity and the space between the two layers of the pericardium and has no connection with the pericardial sac (the space where the heart is located). In this study, the anatomical structure and morphometry of the PPC in immature beluga were investigated, and some approaches were presented to observe the canal in ultrasonography.
Observables from the spinning eikonal
Authors: Luna Andres , Moynihan Nathan , O’Connell Donal , Ross Alasdair
Published: August 2024

Abstract

We study the classical dynamics of spinning particles using scattering amplitudes and eikonal exponentiation. We show that observables are determined by a simple algorithm. A wealth of complexity arises in perturbation theory as positions, momenta and spins must be iteratively corrected at each order. Even though we restrict ourselves to one-loop computations at quadratic order in spin, nevertheless we encounter and resolve a number of subtle effects. Finally, we clarify the links between our work and various other eikonal approaches to spinning observables.
The cosmological constant and the weak gravity conjecture
Authors: Liu Yang , Padilla Antonio , Pedro Francisco G.
Published: August 2024

Abstract

We examine the descent via membrane nucleation through a landscape of vacua where the cosmological constant is given by a combination of four-form fluxes. It has been shown that this descent can be slowed exponentially for very low curvature vacua close to Minkowski space in a wide class of models satisfying certain parametric conditions, providing a possible solution to the cosmological constant problem. We explore in detail whether or not those parametric conditions are compatible with the membrane weak gravity conjecture. Whilst it is true that there is often tension, we show that this is not always the case and present an explicit model where Minkowski space is absolutely stable and the weak gravity conjecture is satisfied. This corresponds to an extension of the Bousso-Polchinski model into a generalised DBI action for four-forms. We also clarify how the landscape should be populated in a consistent model.
Jet rotational metrics
Authors: Romero Alexis , Whiteson Daniel
Published: August 2024

Abstract

Embedding symmetries in the architectures of deep neural networks can improve classification and network convergence in the context of jet substructure. These results hint at the existence of symmetries in jet energy depositions, such as rotational symmetry, arising from the physical features of the underlying processes. We introduce new jet observables, Jet Rotational Metrics (JRMs), which provide insights into the substructure of jets by comparing them to jets with perfect discrete rotational symmetry. We show that JRMs are formidable jet features, achieving good classification scores when used as inputs to deep neural networks. We also show that when used in combination with other jet observables, like N-subjettiness and EFPs, our features increase classification performance. The results suggest that JRMs may capture information not efficiently captured by the other observables, motivating the design of future jet observables for learning the underlying symmetries in the physical processes.
Persistent Homology with Selective Rips Complexes Detects Geodesic Circles
Authors: Virk Žiga
Published: August 2024

This paper introduces a method to detect each geometrically significant loop that is a geodesic circle (an isometric embedding of $$S^1$$

S
1

) and a bottleneck loop (meaning that each of its perturbations increases the length) in a geodesic space using persistent homology. Under fairly mild conditions, we show that such a loop either terminates a 1-dimensional homology class or gives rise to a 2-dimensional homology class in persistent homology. The main tool in this detection technique are selective Rips complexes, new custom made complexes that function as an appropriate combinatorial lens for persistent homology to detect the above mentioned loops. The main argument is based on a new concept of a local winding number, which turns out to be an invariant of certain homology classes.
Psychische Belastung des intensivmedizinischen Personals in Deutschland im Verlauf der COVID-19-Pandemie. Evidenz aus der VOICE-Studie
Authors: Niecke Alexander , Henning Michaela , Hellmich Martin , Erim Yesim , Morawa Eva , Beschoner Petra , Jerg-Bretzke Lucia , Geiser Franziska , Baranowski Andreas M. , Weidner Kerstin , Mogwitz Sabine , Albus Christian
Published: August 2024

Hintergrund

Die Coronavirus(COVID-19)-Pandemie hat das Gesundheitswesen weltweit vor große Herausforderungen gestellt und zu besonderen Belastungen des medizinisch tätigen Personals geführt. Das Ziel dieser Analyse war es zu untersuchen, wie hoch in Deutschland die globale psychische Belastung von in der direkten Krankenversorgung tätigem Personal im Verlauf der COVID-19-Pandemie war.

Methoden

In dieser prospektiven Querschnittstudie mit vier Messzeitpunkten (T1: 4–5/2020, T2: 11/2020–1/2021, T3: 5–7/2021, T4: 2–5/2022) wurden psychische Belastungssymptome im Rahmen eines Online-Surveys mit dem Patient Health Questionnaire (PHQ-4) bei Krankenhauspersonal, das in der direkten Patientenversorgung tätig war, erfasst (N = 5408 Datensätze). Der Gesamtdatensatz wurde explorativ nach Tätigkeitsbereich, Geschlecht und Berufsgruppenzugehörigkeit analysiert sowie der Verlauf über die vier Messzeitpunkte hinweg betrachtet.

Ergebnisse

Eine klinisch relevante psychische Belastung (PHQ-4 ≥ 5) lag bei 29,3 % (n = 419/1429) des intensivmedizinischen Personals vor. Im Vergleich der vier Querschnittserhebungen zeigte sich eine signifikante Steigerung der Rate klinisch relevanter psychischer Belastung im ersten Pandemiejahr (23,2 % zu T1 vs. 30,6 % zu T2; p < 0,01), welche sich im zweiten Pandemiejahr auf hohem Niveau stabilisierte (33,6 % zu T3 bzw. 32,0 % zu T4). Frauen unterschieden sich dabei nicht von den Männern (n = 280/919 vs. n = 139/508 bzw. 30,4 % vs. 27,4 %; p = 0,74). Pflegekräfte waren signifikant häufiger psychisch belastet als ärztliches Personal (n = 339/1105 vs. n = 80/324 bzw. 30,7 % vs. 24,7 %; p = 0,03). Das Intensivpersonal wies keine signifikant höhere Belastung auf als das in nichtintensivmedizinischen Funktionsbereichen tätige Personal (n = 419/1429 vs. n = 1149/3979 bzw. 29,3 % vs. 28,7 %, p = 0,21).

Schlussfolgerung

Mitarbeitende im deutschen Gesundheitswesen gaben in der Pandemie eine hohe und im Verlauf ansteigende psychische Belastung an, jedoch fand sich in unserer Stichprobe kein signifikanter Unterschied zwischen intensivmedizinischem und nichtintensivmedizinischem Personal. Dies ist möglicherweise dadurch bedingt, dass die Pandemie in Deutschland international vergleichsweise moderat verlief und weder ein Kollaps des Gesundheitssystems im Allgemeinen noch eine Dekompensation des intensivmedizinischen Versorgungssektors im Besonderen stattfand.
Transobturator-cable-fixation in pelvic ring injuries with symphyseal disruption – a last resort?
Authors: Jordan Martin C. , Wagner Richard , Hufnagel Lukas , Bremer Justus , Heilig Maximilian , Heilig Philipp , Bretherton Christopher P. , Meffert Rainer H.
Published: August 2024

Purpose

The role of transobturator-cable-fixation (TOCF) in traumatic symphyseal rupture of the pelvic ring remains unclear. This case series aims to evaluate TOCF in complex and revision cases in pelvic surgery.

Methods

A retrospective analysis of a chronological case series was conducted, studying pelvic fractures stabilized using TOCF between January 2006 and December 2022. The variables considered included age, gender, fracture classification, Injury Severity Score (ISS), Body Mass Index (BMI), trauma mechanism, time to surgery, fixation technique, hospital duration, complications, status on discharge (Glasgow Outcome Scale; GOS), follow-up time and indication for the use of TOCF.

Results

All patients (N = 7) were male with a mean age of 64 years and a mean BMI of 29. The mean ISS was 45, with the lowest ISS of 25, indicating that only polytraumatized patients were included. Two anterior-posterior-compression-, four lateral-compression-, and one vertical-shear-pelvic-injury were identified. TOCF was added in six cases to support symphyseal plating and in one case to external fixation. The mean hospital stay was 49 days and the mean follow-up duration was 8.5 months. No complications associated with TOCF were observed during the surgical procedure or follow-up.

Conclusion

TOCF showed no procedure-associated complications and effectively supported symphyseal healing in all cases. The main indications were obesity, poor bone quality in elderly patients, and revision cases. TOCF could be considered as a last treatment option in open-book pelvic injuries where plating or external fixation is at risk to fail.
The Knee injury and Osteoarthritis Outcome Score (KOOS) for lateral tibial plateau fractures– relevance, reliability and responsiveness
Authors: Traerup Jens , Larsen Peter , Elsøe Rasmus
Published: August 2024

Background

This study aimed to evaluate the patient-reported relevance, test-retest reliability, and responsiveness for each of the five KOOS subscales in patients with lateral tibial plateau fractures.

Methods

Adult patients with surgically treated lateral tibial plateau fractures (AO 41B) were included. The primary outcome measure was the KOOS subscales: Pain, Symptoms, Activity of Daily Living (ADL), Sport and Recreational Activities (Sport/rec), and kne-related Quality of Life (QOL). The KOOS was repeated at 14 and 15 days, six weeks, and 6 and 12 months. Content validity was partly evaluated by patients ranking the relevance of all the items in the KOOS, test-retest reliability by an interclass correlation coefficient, and responsiveness by effect size and based on 3 pre-defined hypotheses related the the global rating of change.

Results

Forty-one patients with a mean age of 54.8 years (ranging from 21 to 81 years) were included. The results showed an acceptable relevance of all the KOOS subscales. The test-retest reliability was moderate to high for all five subscales, with an interclass-correlation coefficient ranging from 0.6 to 0.9. At the 6- and 12-month follow-ups, the responsiveness showed large effect sizes for all the KOOS subscales, ranging from 0.9 to 2.1. Moderate to high correlations (r ≥ 0.4)was observed for the predefine hypotheses.

Conclusion

The KOOS questionnaire showed acceptable relevance, high test-retest reliability and acceptable responsivness within one year following a lateral tibial plateau fracture. More research is needed for further validation of psychometric properties of KOOS for patients with lateral tibial plateau fractures.
Analysis of spine motion during prehospital extrication procedures in motorsport
Authors: Uzun Davut Deniz , Klein Roman , Rittmann Adrian , Häske David , Schneider Niko R. E. , Kreinest Michael
Published: August 2024

Purpose

The appropriate extrication techniques for trauma patients after car accidents remain a topic of controversy. Various techniques for immobilizing the cervical spine during prehospital extrication have been investigated.

Methods

This explorative study compared the amount of spinal motion during five different extrication procedures from a racecar and a rallycar performed by two teams: a professional motorsport extrication team and a team of professional emergency medical technicians (EMTs). Two different microelectromechanical systems were used to measure spinal motion, and a motionscore was calculated to compare the amount of remaining spinal motion. A high motionscore indicates high remaining motion and a low motionscore indicates low remaining motion.

Results

The use of an extricable seat results in a mean overall motion score of 1617 [95% CI 308–2926]. Emergency extrication without equipment resulted in the lowest overall motionscore 1448 [95% CI 1070–1826]. In case of urgent extrication the Extrication team attained a motionscore of 2118 [95% CI 517–3718] and the EMT team a motionscore of 2932 [95% CI 1427–4435]. When performing the procedure with the aid of a rescue boa, the EMT team achieved an overall mean motionscore in the same range 2725 [95% CI 568–4881] with boa vs. 2932 [95% CI 1427–4435] without boa. When mean scores of individual spinal segments were analyzed, we found that the EMT team did especially worse in immobilizing the cervical spine 198 vs. 758.

Conclusions

Regular training of extrication procedures has paid off considerably in reducing spinal movement during extrication from a racecar. If an extricable seat is available, extrication should be performed using it. However, if emergency extrication is necessary, an additional manual cervical spine immobilization should be conducted using the Rautek maneuver to sufficiently reduce cervical spine movement.
Hemoglobin level, degree of mobilization, and pneumonia are associated with the development of postoperative delirium in cemented hemiarthroplasty after femoral neck fracture
Authors: Riemenschneider Julia , Dobrawa Pascal , Sturm Ramona , Meier Simon L. , Verboket René , Marzi Ingo , Störmann Philipp
Published: August 2024

Purpose

The aim of this retrospective study was to identify independent prognostic factors for developing a postoperative delirium (POD) in patients suffering from a proximal femoral neck fracture and treated by implantation of a hemiprosthesis.

Methods

A retrospective study, including patients with hip hemiarthroplasty due to a femoral neck fracture between 2011 and 2020 was performed. Demographic data, preexisting conditions, intra-/postoperative complications, mobilization and laboratory results were extracted from the patients’ charts. The different parameters were analyzed comparing patients with and without POD.

Results

412 patients, mean age of 81 ± 9.58 years were included, 66.5% (n = 274) were female, 18.2% (n = 75) of them developed a POD. Significantly higher incidence of POD was associated with older age (p < 0.001), lower level of haemoglobin (p < 0.001), higher post-surgery interleukin 6 (IL 6) level (p = 0.008), higher postoperative level of leukocytes (p = 0.01). Patients with POD received more units of packed red blood cells (PRBC) (p = 0.007). Patients with no mobility limitations pre-operatively developed POD less frequently (p = 0.01), whereas suffering from pneumonia (p = 0.03) or limited mobility postoperatively increased the risk of POD (p < 0.001).

Conclusion

This study could help to identify patients with a risk for developing POD after a hemiarthroplasty in femoral neck fractures. As a consequence, frequent controls of Hb, IL 6 and leucocytes levels to avoid anemia and infections, as well as the well surgical treatment to guarantee a good postoperative outcome.
Microstructures and mechanical properties of friction stir welded additively manufactured Scalmalloy®
Authors: Mirandola Pietro , Novel David , Perini Matteo , Benedetti Matteo , Lombardi Franco , Lunetto Vincenzo , Spena Pasquale Russo
Published: August 2024

The development of high-strength advanced additively manufactured (AM) aluminum alloys is driven by the need for weight reduction in complex-shaped structural applications. In this context, heat-treatable aluminum-scandium alloy, known commercially as Scalmalloy®, offers high strength and lightness, also at high temperatures, due to solution strengthening Al3(Sc, Zr) particles. A widespread diffusion of such AM alloy is also related to welding technologies that could preserve its engineered microstructure. This study investigates the microstructural and mechanical properties of butt friction stir welding (FSW) joints of LPBF Scalmalloy® plates under different welding settings. Joint performance was evaluated under quasi-static and cyclic loading conditions. Porosity in Scalmalloy® and welds was assessed using 3D X-ray computed tomography. An aging heat treatment assessed the extent of precipitation hardening in the FSW joints. Results show that metal stirring during FSW notably reduced the intrinsic porosity of Scalmalloy®, decreasing the equivalent pore diameter from about 200 μm to 60 μm in the welded joints. Under quasi-static loading, welded specimens failed at the interface between the thermo-mechanically affected and the stir zones on the advancing side. The aging heat treatment improved the mechanical strength of Scalmalloy® from approximately 400 to 480 MPa, albeit at the expense of ductility (elongation at fracture decreased from 16 to 4%). The higher heat input and stirring developed at a low welding speed reduced lazy S defects but limited the effectiveness of subsequent aging. In fatigue testing, welded joints consistently failed within the aged base material due to the intrinsic porosity of Scalmalloy®.
Impact of additives on syntrophic propionate and acetate enrichments under high-ammonia conditions
Authors: Pinela Eduardo , Schnürer Anna , Neubeck Anna , Moestedt Jan , Westerholm Maria
Published: August 2024

High ammonia concentrations in anaerobic degradation systems cause volatile fatty acid accumulation and reduced methane yield, which often derive from restricted activity of syntrophic acid-oxidising bacteria and hydrogenotrophic methanogens. Inclusion of additives that facilitate the electron transfer or increase cell proximity of syntrophic species by flocculation can be a suitable strategy to counteract these problems, but its actual impact on syntrophic interactions has yet to be determined. In this study, microbial cultivation and molecular and microscopic analysis were performed to evaluate the impact of conductive (graphene, iron oxide) and non-conductive (zeolite) additives on the degradation rate of acetate and propionate to methane by highly enriched ammonia-tolerant syntrophic cultures derived from a biogas process. All additives had a low impact on the lag phase but resulted in a higher rate of acetate (except graphene) and propionate degradation. The syntrophic bacteria ‘Candidatus Syntrophopropionicum ammoniitolerans’, Syntrophaceticus schinkii and a novel hydrogenotrophic methanogen were found in higher relative abundance and higher gene copy numbers in flocculating communities than in planktonic communities in the cultures, indicating benefits to syntrophs of living in close proximity to their cooperating partner. Microscopy and element analysis showed precipitation of phosphates and biofilm formation in all batches except on the graphene batches, possibly enhancing the rate of acetate and propionate degradation. Overall, the concordance of responses observed in both acetate- and propionate-fed cultures highlight the suitability of the addition of iron oxide or zeolites to enhance acid conversion to methane in high-ammonia biogas processes.

Key points

• All additives promoted acetate (except graphene) and propionate degradation.

• A preference for floc formation by ammonia-tolerant syntrophs was revealed.

• Microbes colonised the surfaces of iron oxide and zeolite, but not graphene.

Graphical Abstract
Scandinavium lactucae sp. nov. Isolated from Healthy Lettuce in South Korea
Authors: Park Jiwon , Park Sieun , Oh Kwang-Kyo , Franz Charles M. A. P. , Cho Gyu-Sung
Published: August 2024

Four Gram-negative, facultative anaerobic, oxidase-negative and catalase-positive strains were isolated from lettuce sample collected from test beds at the National Institute of Agricultural Sciences in Wanju, South Korea. The whole genome sequences of the strains ranged from 4,624,629 to 4,849,846 bp in size, with DNA G + C contents of 54.32 to 54.56 mol%. Phylogenetic analyses based on 16S rRNA gene and four housekeeping (atpD, gyrB, infB, and rpoB) gene sequences showed that the four strains clustered closely together with Scandinavium type strains within the Enterobacteriaceae family. Moreover, the average nucleotide identity and digital DNA-DNA hybridization value of the proposed type strain (V105_6T) with the closely related Scandinavium type strains were in the range of 85.71–86.16% and 30.2–31.2%, respectively, which were all below the species delineation threshold values. The major cellular fatty acid of V105_6T was C16:0. Growth was observed at 7, 10 and 35 °C, and in the presence of 7% NaCl concentration. Based on phenotypic and genotypic results, strain V105_6T represents a novel species of the genus Scandinavium, for which the name Scandinavium lactucae sp. nov. is proposed. The type strain is V105_6T (= LMG 33389T = DSM 117134T).