bluuebunny/crossref_metadata_2025 huggingface dataset:
Non-contact online inspection method for the appearance diameter uniformity of chemical fiber filaments
Authors: Liu Xiangyu , Gan Xuehui , Liao He , Ping An , Qian Xiaomin , Zhang Xiaoxiao
Published: October 2023

As chemical fiber filaments diameter variation directly affects spinning quality, spinning condition monitoring becomes more and more important in an intelligent manufacturing environment. Firstly, based on the single-slit Fraunhofer diffraction model and the Babinet principle, the non-contact filaments diffraction model is developed to generate diffraction fringe patterns by irradiating chemical fiber filaments with He–Ne laser. Secondly, for the characteristics of diffraction fringe patterns, a segmentation mask window-based diffraction fringe center of gravity extraction method is proposed, and a zero-phase Butterworth low-pass filter is designed and applied to the diffraction light intensity curves to accurately extract the extreme points positions of the adjacent dark fringe and calculate the diameter information. Finally, the non-contact chemical fiber filaments appearance diameter online inspection experiment platform is built to carry out static and dynamic experiments of filaments. The experimental results show that the maximum absolute value of absolute error is less than 1.1 μm for static measurement and less than 10 μm for dynamic measurement.
Sunlight-driven CO2 utilization over two-dimensional Co-based nanosheets
Authors: Gao Linjie , Wang Haixiao , Wang Yachuan , Liu Bang , Zhang Weifeng , Li Yaguang
Published: October 2023

Reverse water gas shift (RWGS) reaction is an intriguing strategy to realize carbon neutrality, however, the endothermic process usually needs high temperature that supplied by non-renewable fossil fuels, resulting in secondary energy and environmental issues. Photothermal catalysis are ideal substitutes for the conventional thermal catalysis, providing that high reaction efficiency is achievable. Two-dimensional (2D) materials are highly active as RWGS catalysts, however, their industrial application is restricted by the preparation cost. In this study, a series of 2D Co-based catalysts for photothermal RWGS reaction with tunable selectivity were prepared by self-assembly method based on cheap amylum, by integrating the 2D catalysts with our homemade photothermal device, sunlight driven efficient RWGS reaction was realized. The prepared 2D Co0.5Ce0.5O
x
exhibited a full selectivity toward CO (100%) and could be heated to 318 °C under 1 kW m−2 irradiation with the CO generation rate of 14.48 mmol g−1 h−1, pointing out a cheap and universal method to prepare 2D materials, and zero consumption CO generation from photothermal RWGS reaction.
Tunable 3D printed composite metamaterials with negative stiffness
Authors: Wu Changlang , Peng Chenxi , Le Tu C , Das R , Tran Phuong
Published: October 2023

The paper proposes a class of tunable metamaterials that use inclined beams to achieve instability in a rigid system. Three different beam tilt angles, 25°, 45°, and 60°, are evaluated in the form of unit cells using quasi-static compression tests and numerical simulations. Snap-through behavirous are characterised by structural stiffness and buckling load. Periodic and gradient structures are assembled and analysed by arranging the unit cells in rows and columns. Size effect analyses and parametric studies are carried out on various unit-cell arrangements and different beam angles. The proposed metamaterials are manufactured through fused filament fabrication 3D printing technology with a composite material, onyx. The results from experiments, finite element analysis, and analytical models are compared and evaluated. The structural stiffness and buckling load are shown to be positively related to the inclination angle of the tilted beams. The number of rows of unit cells governs the nonlinear mechanical response (number of snap-throughs) of multiple-layered structures. By increasing the number of rows and columns of unit cells, which are less prone to manufacturing defects, the reliability and repeatability of the structural properties of periodic/gradient structures could be improved. A design plot is also provided to predict and tune the snap-through behaviour of multiple-layered structures via beam angles and unit-cell arrangements.
The interplay between anomalous metallic and superconducting states tuned by disorder in thin flakes of Kagome metal KV3Sb5
Authors: Wang Teng , Yu Aobo , Mao Yuanlv , Fang Yuqiang , Liu Yixin , Zhang Han , Guo Wang , Li Wei , Peng Wei , Di Zengfeng , Huang Fuqiang , Jiang Da , Mu Gang
Published: October 2023

Recently, V-based Kagome metals have attracted intense attention due to the coexistence of their topological nontrivial electronic structure, charge density wave, and superconductivity. Here, we report the fabrication and physical investigations of single-crystalline thin flakes of the Kagome metal KV3Sb5. For samples with a thickness of

22
±
2
 

n
m

, Berezinskii–Kosterlitz–Thouless type behavior is revealed by the temperature dependent resistance and voltage–current data, which indicates the presence of two-dimensional superconductivity. Meanwhile, a temperature-independent resistance behavior is observed in a wide field region, supplying the hallmark of the anomalous metallic (AM) state. Importantly, by comparing the interplay between the superconducting and AM states of two samples with different levels of disorder, a striking competitive evolution with the external field between these two states is uncovered.
The study of optical and electrical properties of AgInS2-based composite
Authors: Wen Junjie , Zhang Fan , Yu Qiang , Zhao Yue
Published: October 2023

Abstracts

Photovoltaic solar energy was one of the few sustainable and pollution-free energy sources. AgInS2 was a promising photovoltaic material, which had attracted considerable in long time due to its outstanding photovoltaic performance. Furthermore, the nanoparticles could improve the light absorption efficiency of absorption layer to enhance the photoelectric conversion efficiency of solar cell. In this paper, the suitable preparation methods of AgInS2 film and gold nanoparticles were used to improve the optical-electric performances of AgInS2-based solar cell. AgInS2 films were prepared by vacuum evaporation using different raw materials (Ag + In + S and Ag2S + In2S3) and then annealed at 400 °C or 425 °C. From absorption spectrum, the AgInS2 film, which was prepared by two components (Ag2S + In2S3) and annealed at 400 °C, had the highest absorption. And the transmission spectrum of the AgInS2 film was similar to that obtained from finite difference time domain simulation. Furthermore, this AgInS2 film was used to prepare AgInS2/CdS PN junction and AgInS2/gold/CdS PN junction. Due to the introduction of gold nanoparticles, the forward current of the AgInS2/gold/CdS PN junction increased an order of magnitude, but ideal factor and barrier height decreased, which meant that gold nanoparticles can promote carrier transport and improve electric property. As a result, this AgInS2/gold/CdS PN junction owned high absorption efficiency, low reverse saturation current and large barrier height, which meant huge application potential in solar cells field.
Performance enhancement of CsPbI3-xBrx perovskite solar cells via graded bandgap and affinity engineering
Authors: Kashyap Savita , Pandey Rahul , Madan Jaya
Published: October 2023

All inorganic cesium lead-based perovskite solar cells (PSCs) have gained attention as alternative absorbing materials owing to their exceptional thermal stability. However, these devices are suffer from transmission and thermalization losses. Therefore, a novel grading approach is used in CsPbI3-x Brx perovskite solar cell to reduce the transmission and thermalization losses by enhancing the cell’s ability to capture a broad spectrum of light wavelengths and suitably accommodate the material’s energy bandgap. In this work, the performance of CsPbI3-xBrx perovskite solar cell with graded bandgap (Eg) and affinity has been explored and analyzed using the simulation SCAPS-1D tool. Different compositions (x) are varied to adjust the bandgap of CsPbI3-xBrx with different grading profiles such as linear, parabolic and beta grading. The graded structure enhances the absorption wavelength range and carrier lifetime. However, it also leads to the redistribution of the electrical field within the device, promoting more effective charge separation and collection. By utilizing this approach, the impact of absorber thickness variations from (50 nm to 700 nm) is also studied and analyzed with respect to grading profiles. Initially, 16.75% power conversion efficiency (PCE) is obtained by calibrating the experimental CsPbI3-xBrx graded solar cell. Then, performance is further improved by adjusting the bandgap with grading profiles, optimizing ETLs/HTLs and achieving optimum PV parameters: short-circuit current density (JSC) of 20.50 mA cm−2, open-circuit voltage (VOC) of 1.35 V, fill factor (FF) of 84.15% and PCE of 23.11%. The findings of the reported study would significantly provide a path for the development of graded PSC.
Electrical characteristics of different concentration of silica nanoparticles embedded in epoxy resin
Authors: Al Soud Ammar , Daradkeh Samer I. , Knápek Alexandr , Holcman Vladimír , Sobola Dinara
Published: October 2023

In this study, modified epoxy nanocomposite was produced by incorporating SiO2 nanoparticles of 15–30 nm in size, with different concentrations ranging from 1 to 20 wt%. The electrical properties of the epoxy nanocomposite were measured at room temperature in the frequency range of 10−2–107 Hz. To determine the impact of nanoparticles on the epoxy composition, scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDS), Fourier transform infrared spectra (FTIR) spectroscopy, and Raman spectroscopy were conducted. With an increase in filler (SiO2 nanoparticles) content, the electrical characteristics of the epoxy nanocomposite exhibited multiple changes. At low concentrations, all electrical properties experienced a notable increase. The epoxy with 15 wt% of SiO2 nanoparticles samples had a lower permittivity, loss number, conductivity, and capacitance than the unfilled epoxy. At medium concentrations (5 to 15 wt%), the formation of immobilized nanolayers has an impact on permittivity, loss number, conductivity, and capacitance, which have decreased; impedance and modulus increased. The initiation of contact between the nanofillers at a concentration of 20 wt% leads to the formation of continuous interfacial conductive pathways, resulting in a dramatic increase in the permittivity, conductivity, and capacitance of the composites, while concurrently reducing impedance.
Exploration of temperature driven conduction process and ferroelectric properties of Mn doped GdCrO3
Authors: Qahtan Aref A A , Somvanshi Anand , Manzoor Samiya , Fatema Mehroosh , Abushad M , Zarrin Naima , Khan Wasi , Husain Shahid
Published: October 2023

This work delivers the research findings of the temperature dependent DC resistivity, AC impedance and ferroelectric polarization of GdCr1−xMnxO3 (x = 0 and 0.3). Mixed valence states of Cr (Cr3+ and Cr4+) are explored using the x-ray photoelectron spectroscopy analysis. The exponential decay of DC resistivity on escalating the temperature advocates the semiconducting-like nature for the probed samples. The DC resistivity data of these samples fit well into small-polaron hopping and variable range hopping models. The impedance attributes of these samples were scrutinized over a broad spectrum of temperatures at selected frequencies. The values of the real and imaginary parts of impedance unveil substantial reduction on raising the temperature, thereby signifying the increase in conductivity of the samples. Pristine sample displays an electrical relaxation peak at 65 °C, which translates towards the lower temperature at higher frequencies. Further, the semicircular behavior of Nyquist plots at higher temperatures indicates the reduction of the charge transfer resistance. The equivalent circuits of Nyquist plots are generated using Z-view software. From these plots, it is perceived that grain boundary resistance upsurges while the grain resistance and capacitance drops upon doping. The ferroelectric measurements reveal that the coercive field (Ec) values decrease whereas the values of maximum polarization (Pm), remnant polarization (Pr) and energy storage increase in 30% doped GdCrO3. These observations establish that electrical and ferroelectric properties of GdCrO3 system can be tuned with appropriate Mn doping.
Composite hybrid inflation: dilaton and waterfall pions
Authors: Cacciapaglia Giacomo , Cheong Dhong Yeon , Deandrea Aldo , Isnard Wanda , Park Seong Chan
Published: October 2023

We investigate the possibility that inflation originates from a composite field theory, in terms of an effective chiral Lagrangian involving a dilaton and pions. The walking dynamics of the theory constrain the potential in a specific way, where the anomalous dimensions of operators involving pions play a crucial role. For realistic values of the anomalous dimensions, we find a successful hybrid inflation occurring via the dilaton-inflaton, with the pions acting as waterfall fields. Compositeness consistency strongly constrain the model, predicting a dilaton scale fχ
∼ 𝒪 (1) in unit of the Planck scale, an inflation scale H
inf ∼ 1010 GeV, and the pion scale around 1014 GeV. We further discuss possible phenomenological consequences of this theory.
A 14-bit 1-GS/s Pipelined-SAR ADC in 28-nm CMOS with Foreground and Background Calibration
Authors: Han Shuai , Li Zhiyang , Ding Kaijie , Cao Tianxiang , Xu Zhiwei
Published: October 2023

A 14-bit 1-GS/s Pipelined-Successive Approximation Register (SAR) Analog-to-Digital Converter (ADC) in 28-nm CMOS is presented in this paper. In the initial phase, a pair of SAR ADCs employing the Time-Interleaved (TI) technique are employed to attain the necessary sampling rate. A multi-comparators structure is used to increase the speed and improve the mismatch. We have implemented a foreground calibration technique to address capacitor mismatch, optimizing its processing logic to enhance the chip’s speed. The interstage operational amplifier adopts a two-stage structure. Some structural changes are presented to optimize its bandwidth and phase margin. A background calibration method for gain error is implemented. In the subsequent phase, we employ four SAR ADCs utilizing the TI method. The outcomes demonstrate that the ADC delivers a Signal-to-Noise and Distortion Ratio (SNDR) of 65.58 dB and a Spurious-Free Dynamic Range (SFDR) of 72.12 dB at a 1-GS/s sampling rate without calibration, and 69.02 dB SNDR and 81.26 dB SFDR at the same 1-GS/s sampling rate with calibration. The core layout occupies an area of 0.6 mm2 and consumes 225.02 mW of power.
A Closed-Loop VCO-based 1-1 SMASH CT ΔΣ ADC Architecture
Authors: Zhong Yi , Shao Jin , Men Changyou , Sun Nan
Published: October 2023

A novel closed-loop voltage-controlled oscillator (VCO)-based 1-1 sturdy multistage noise-shaping (SMASH) continuous-time ΔΣ ADC is presented in this paper. The proposed architecture uses VCOs as integrators and puts them in a closed loop to suppress the VCO nonlinearity. The multi-bit quantization is employed in the proposed architecture so that the requirement of a high over-sampling ratio (OSR) is relaxed while maintaining a high resolution. The architecture has been verified in MATLAB Simulink.
Study on effective elastic thickness of lithosphere and its tectonic significance in surrounding area of Ordos Block
Authors: Zhang Yongqi , Zhai Hongguang , Zhang Enhui , Ding Xiaoguang
Published: October 2023

Based on EIGEN6C4 gravity field model data and ETOPO1 topographic data, we adopt the correlation analysis method based on Fan wavelet to calculate and analyze the distribution characteristics of effective elastic thickness (Te) and load ratio (F) of lithosphere in surrounding of Ordos block. On this basis, the relationship between the lithosphere Te and geological structure, seismic distribution, terrestrial heat flow and crustal deformation is analyzed. The results show that the lithosphere Te in the surrounding area of the Ordos block is obviously different among the tectonic blocks. The lithosphere Te value is low in the south of Qinling orogenic belt and the east of Fen-Wei graben basin. The maximum lithosphere Te value is distributed in the northwest and northeast margin of Ordos block. The lithosphere Te value is negatively correlated with the load ratio F. Earthquakes mainly occur in areas with low lithosphere Te value. Small lithosphere Te value indicates low strength of lithosphere. In such areas, the ability to resist crustal deformation is weak, and it is easy to generate stress accumulation and breed earthquakes. The area with high terrestrial heat flow value corresponds to low lithosphere Te value, showing a negative correlation. However, this negative correlation does not exist in the northwest margin of Ordos Block and Alashan border area, and the eastern margin of Ordos Lvliangshan area. Haiyuan-Liupanshan area has strong tectonic activity, frequent earthquakes and low lithosphere Te value. The internal strain accumulation of Ordos block is small, and the lithosphere Te value is high. The strain rate of the northern Shanxi fault depression zone is large, but the lithosphere Te value is also large, it is speculated that the terrestrial heat flow is the main factor affecting the lithosphere Te value.
Effect of annealing on the room temperature luminescence of coumarin 106 in PVA films
Authors: Alexander Emma , Ceresa Luca , Pham Danh , Gryczynski Zygmunt , Gryczynski Ignacy
Published: October 2023

We studied the effect of annealing on the luminescence of Coumarin 106 (C106) in poly (vinyl alcohol) films (PVA films). The samples and reference polymer films were treated at temperatures between 100 °C and 150 °C (212 F and 302 F) for various times. After cooling and smoothing, the samples and references were measured at room temperature. We observed that the PVA polymer (reference films) changes its optical properties with annealing at higher temperatures, affecting the baselines in absorption and the backgrounds in emission measurements. This requires precise background subtractions and control of the signal-to-noise ratio. Whereas the fluorescence intensity of C106 in PVA films modestly decreases with annealing, the phosphorescence depends dramatically and progressively increases by many folds. The fluorescence quantum yields and lifetimes decrease with the annealing, which suggests an increase in the non-radiative processes in the singlet excited state S1. The increase in the phosphorescence intensities results from increased intersystem crossing (ISC), which also decreases fluorescence. We also studied the effect of annealing on phosphorescence with the directly excited triplet state of C106. In this case, two processes are affected by annealing, S0→T1 absorption and T1→S0 phosphorescence. The long-wavelength excitation (475 nm) avoids PVA polymer excitation. The phosphorescence lifetime decreases with annealing while the phosphorescence intensity increases. These changes suggest that the radiative rate of T1 → S0 increases with annealing.
Heterogenous climate impacts on crop yields: evidence from Ukraine
Authors: Fang Ming , Jin Songqing , Deininger Klaus , Gammans Matthew
Published: October 2023

Ukraine ranks among the largest global producers and exporters of a variety of agricultural commodities. Despite its importance, there is limited research on the effect of climate change on the future of Ukraine’s agricultural sector. We investigate how weather affects the yields of Ukraine’s five major crops: winter wheat, spring barley, sunflower, soybean, and corn. Using panel data on village-level surveyed crop yields and fine-scale weather data from 2004–2020, we estimate flexible statistical yield models to characterize the impact of temperature and precipitation changes on crop yields. A simple linear model of the effect of average temperature and precipitation on yields suggests warming is beneficial for all crops in Ukraine. However, a more flexible model of the temperature-yield relationship implies that the yields of two cold-season crops, winter wheat and spring barley, respond negatively to temperatures above 29 °C and 30 °C, respectively. We find no negative effects of high temperatures for the three warm-season crops. We conclude that both average temperature and exposure to high temperatures affect Ukrainian yields.
Assessment of technology-assisted technician verification of compounded intravenous sterile preparations versus pharmacist verification
Authors: Abbasi Aimen , Franz Noah
Published: October 2023

Purpose

This study is an evaluation of technology-assisted technician verification (TATV) of the compounded sterile product (CSP) preparation process as an alternative to final verification by a pharmacist.

Methods

A 2-phase, single-center noninferiority study was conducted to assess the accuracy and CSP processing time with TATV versus pharmacist verification. Phase I of the study was a validation of the internal pharmacist accuracy rate in which 2 pharmacists checked each CSP. In phase II, prepared CSPs were first checked by a technician and then checked by a pharmacist. Technicians were required to complete baseline credentialing and training requirements to participate in the study. The primary outcome was the error rate for the pharmacist check in phase I and the error rate of the technician check in phase II. Secondary outcomes included total verification time and total dose processing time in each phase. The Farrington-Manning test was used for noninferiority assessment of accuracy, and the Wilcoxon rank sum test was used to detect a difference between the processing times.

Results

A total of 4,000 doses were checked in each phase. Pharmacist accuracy was 99.600% in phase I, compared to TATV accuracy of 99.575% in phase II. TATV of CSPs was noninferior to pharmacist verification (absolute difference in accuracy, 0.025%; 95% CI, –0.26% to 0.31%; P = 0.0016). Total verification time and total dose processing times were significantly lower in Phase II.

Conclusion

This study showed that TATV of CSPs is noninferior to pharmacist final verification and does not negatively impact the time to check CSPs or total CSP processing time.
CoreDetector: a flexible and efficient program for core-genome alignment of evolutionary diverse genomes
Authors: Fruzangohar Mario , Moolhuijzen Paula , Bakaj Nicolette , Taylor Julian
Published: October 2023

Motivation

Whole genome alignment of eukaryote species remains an important method for the determination of sequence and structural variations and can also be used to ascertain the representative non-redundant core-genome sequence of a population. Many whole genome alignment tools were first developed for the more mature analysis of prokaryote species with few current tools containing the functionality to process larger genomes of eukaryotes as well as genomes of more divergent species. In addition, the functionality of these tools becomes computationally prohibitive due to the significant compute resources needed to handle larger genomes.

Results

In this research, we present CoreDetector, an easy-to-use general-purpose program that can align the core-genome sequences for a range of genome sizes and divergence levels. To illustrate the flexibility of CoreDetector, we conducted alignments of a large set of closely related fungal pathogen and hexaploid wheat cultivar genomes as well as more divergent fly and rodent species genomes. In all cases, compared to existing multiple genome alignment tools, CoreDetector exhibited improved flexibility, efficiency, and competitive accuracy in tested cases.

Availability and implementation

CoreDetector was developed in the cross platform, and easily deployable, Java language. A packaged pipeline is readily executable in a bash terminal without any external need for Perl or Python environments. Installation, example data, and usage instructions for CoreDetector are freely available from https://github.com/mfruzan/CoreDetector.
LexicHash: sequence similarity estimation via lexicographic comparison of hashes
Authors: Greenberg Grant , Ravi Aditya Narayan , Shomorony Ilan
Published: October 2023

Motivation

Pairwise sequence alignment is a heavy computational burden, particularly in the context of third-generation sequencing technologies. This issue is commonly addressed by approximately estimating sequence similarities using a hash-based method such as MinHash. In MinHash, all k-mers in a read are hashed and the minimum hash value, the min-hash, is stored. Pairwise similarities can then be estimated by counting the number of min-hash matches between a pair of reads, across many distinct hash functions. The choice of the parameter k controls an important tradeoff in the task of identifying alignments: larger k-values give greater confidence in the identification of alignments (high precision) but can lead to many missing alignments (low recall), particularly in the presence of significant noise.

Results

In this work, we introduce LexicHash, a new similarity estimation method that is effectively independent of the choice of k and attains the high precision of large-k and the high sensitivity of small-k MinHash. LexicHash is a variant of MinHash with a carefully designed hash function. When estimating the similarity between two reads, instead of simply checking whether min-hashes match (as in standard MinHash), one checks how “lexicographically similar” the LexicHash min-hashes are. In our experiments on 40 PacBio datasets, the area under the precision–recall curves obtained by LexicHash had an average improvement of 20.9% over MinHash. Additionally, the LexicHash framework lends itself naturally to an efficient search of the largest alignments, yielding an O(n) time algorithm, and circumventing the seemingly fundamental O(n2) scaling associated with pairwise similarity search.

Availability and implementation

LexicHash is available on GitHub at https://github.com/gcgreenberg/LexicHash.
Generalized hyperpigmented and hypopigmented macules and papules
Authors: Sun Lanyu , Sousa Diogo , de Vasconcelos Pedro , Antunes Joana , Soares-de-Almeida Luís , Filipe Paulo
Published: October 2023

A 49-year-old White woman with an unremarkable medical history presented with mildly pruritic hyperpigmented and hypopigmented macules and papules scattered across her face, trunk and limbs since her twenties.
Assessing the Impact of the COVID-19 Pandemic on the Severity of Pediatric Inflammatory Bowel Disease Admissions and New Diagnoses
Authors: Waschmann Malika , Stuart Ariana , Trieschmann Kimberly , Lin Henry C , Hunter Anna K
Published: October 2023

Introduction

The COVID-19 pandemic has introduced new challenges to the diagnosis and management of pediatric inflammatory bowel disease (IBD). Many patients have had only limited access to their providers through telemedicine, and many chose to delay nonemergent treatment.

Methods

A retrospective chart review of patients with IBD seen by the Pediatric Gastroenterology Division at Doernbecher Children’s Hospital from January 2018 to August 2021 was conducted. The study cohort was divided into 2 groups: those presenting before the onset of the COVID-19 pandemic (January 1, 2018 to February 28, 2020) and those presenting during the pandemic (March 1, 2020 to August 1, 2021). Variables collected included: age, sex, race, ethnicity, IBD type, insurance type, location of residence. Primary outcome measures selected focused on disease severity, initial type of treatment, or surgical intervention offered. A subgroup analysis of the new diagnosis patients was performed. Data were analyzed using independent t-tests, chi-squared analysis, and Wilcoxon rank sum tests.

Results

Two hundred and eleven patients met inclusion criteria, 107 (72 new diagnoses, 35 admissions) within the pre-COVID epoch and 104 (67 new diagnoses, 37 admissions) within the during-COVID epoch. Patients in the during-COVID epoch had higher fecal calprotectin level and were more likely to be started on a biologic as initial treatment. Patients admitted during COVID for IBD flare were more likely to require surgical intervention. Subgroup analysis of newly diagnosed patients revealed higher incidence of comorbid depression and anxiety.

Conclusions

Our review identified increased disease severity in newly diagnosed pediatric patients with IBD as well as pediatric patients admitted for flare during COVID. Increases in anxiety and depression rates during COVID may have contributed to worsened disease severity.
A rare presentation of acute myocarditis as a manifestation of adult-onset Still’s disease: a case report
Authors: Dick Michael , Innes-Jones Kyra , Arri Satpal
Published: October 2023

Background

Adult-onset Still’s disease (AOSD) is a rare systemic autoinflammatory condition characterized by a classical triad of symptoms that include prolonged fever, polyarthritis, and a characteristic salmon-pink skin rash. It can affect a variety of organ systems resulting in many different clinical presentations and is usually a diagnosis of exclusion. Myocarditis complicated by cardiogenic shock is a rare and life-threatening manifestation of AOSD, typically affecting younger patients. There is a limited experience and evidence in how best to manage this challenging patient cohort.

Case summary

A previously fit and well 22-year-old male presented with fever, arthralgia, and general malaise. On clinical examination, he was pyrexial and hypotensive, requiring vasopressor support for presumed septic shock. Subsequent transthoracic echocardiography and cardiac MRI findings were in keeping with fulminant myocarditis. Further septic and auto-immune screens were negative although he responded well to high-dose intravenous corticosteroids. Attempts to wean immunosuppression were unsuccessful, and his ferritin was markedly elevated (20 233 μg/L). A diagnosis of AOSD was suspected after exclusion of other possible causes. The successful addition of tocilizumab (an interleukin-6 receptor antagonist) therapy allowed for gradual de-escalation of steroid therapy and disease remission, with on-going remission at 18 months on maintenance therapy.

Discussion

This case highlights the importance of considering AOSD as a rare cause for myocarditis, especially when fever is present, or disease is severe. Failure to improve with first-line therapy involving high-dose corticosteroids, or inability to wean that therapy, should prompt consideration for escalation of therapy, with tocilizumab seemingly an effective treatment option.
Right heart echocardiography findings in hypoxic pneumonia patients during the COVID-19 pandemic in a South African population
Authors: van Blydenstein S A , Omar S , Jacobson B , Menezes C N , Meel R
Published: October 2023

Aims

The right ventricle is affected by Coronavirus disease 19 (COVID-19) via multiple mechanisms, which can result in right ventricular dysfunction (RVD). This study aimed to provide an assessment of right heart function using conventional echocardiography and advanced strain imaging, in patients with hypoxic pneumonia during the COVID-19 pandemic.

Methods and results

This study was an observational, prospective, single-centre study, including adults with hypoxic pneumonia, in two groups: COVID-19 pneumonia; and non-COVID-19 pneumonia. Bedside echocardiography was performed according to a pre-specified protocol and all right heart measurements were done as per standard guidelines. Right ventricular free wall strain (RVFWS) was measured using Philips® QLAB 11.0 speckle tracking software. Descriptive and comparative statistics were used to analyse data. Spearman Rank Order Correlations were used to determine the correlation between right ventricular (RV) parameters and clinical parameters. Univariate and multivariate logistic regression analyses were performed to characterize the predictors of in-hospital mortality. We enrolled 48 patients with COVID-19 pneumonia and 24 with non-COVID-19 pneumonia. COVID-19 patients were significantly older with a higher frequency of hypertension and diabetes and a trend towards a lower severity of illness score. Mean RVFWS yielded the highest estimates for the prevalence of RVD (81%), with no difference between the two pneumonia groups. Median Tricuspid Annular Plane Systolic Excursion (TAPSE) and right ventricular systolic excursion velocity (RVS’) were not significantly different between COVID-19 (TAPSE 17.2 and RVS’ 12), and non-COVID-19 pneumonia (TAPSE 17.8 and RVS’ 12.1) with P values of 0.29 and 0.86, respectively. Non-COVID-19 pneumonia patients with moderate to severe hypoxaemia (PF < 150) were at greater risk of an elevated RV Systolic Pressure >30 mmHg respiratory rate = 3.25 (CI 1.35–7.82) on admission. Troponin levels discriminated between COVID-19 survivors (6 ng/L) and non-survivors (13 ng/L), P = 0.04. The mortality rate for COVID-19 was high (27%) compared to non-COVID-19 pneumonia (12%).

Conclusion

Patients with COVID-19 pneumonia had a similar admission prevalence of RVD when compared to patients with non-COVID-19 pneumonia. Despite preserved traditional parameters of RV systolic function, RVFWS was diminished in both groups, and we propose that RVFWS serves as an important marker of the subclinical disease of RV.
Non-invasive left ventricular pressure-volume loops from cardiovascular magnetic resonance imaging and brachial blood pressure: validation using pressure catheter measurements
Authors: Arvidsson Per M , Green Peregrine G , Watson William D , Shanmuganathan Mayooran , Heiberg Einar , De Maria Giovanni Luigi , Arheden Håkan , Herring Neil , Rider Oliver J
Published: October 2023

Aims

Left ventricular (LV) pressure-volume (PV) loops provide gold-standard physiological information but require invasive measurements of ventricular intracavity pressure, limiting clinical and research applications. A non-invasive method for the computation of PV loops from magnetic resonance imaging and brachial cuff blood pressure has recently been proposed. Here we evaluated the fidelity of the non-invasive PV algorithm against invasive LV pressures in humans.

Methods and results

Four heart failure patients with EF < 35% and LV dyssynchrony underwent cardiovascular magnetic resonance (CMR) imaging and subsequent LV catheterization with sequential administration of two different intravenous metabolic substrate infusions (insulin/dextrose and lipid emulsion), producing eight datasets at different haemodynamic states. Pressure-volume loops were computed from CMR volumes combined with (i) a time-varying elastance function scaled to brachial blood pressure and temporally stretched to match volume data, or (ii) invasive pressures averaged from 19 to 30 sampled beats. Method comparison was conducted using linear regression and Bland-Altman analysis. Non-invasively derived PV loop parameters demonstrated high correlation and low bias when compared to invasive data for stroke work (R2 = 0.96, P < 0.0001, bias 4.6%), potential energy (R2 = 0.83, P = 0.001, bias 1.5%), end-systolic pressure-volume relationship (R2 = 0.89, P = 0.0004, bias 5.8%), ventricular efficiency (R2 = 0.98, P < 0.0001, bias 0.8%), arterial elastance (R2 = 0.88, P = 0.0006, bias −8.0%), mean external power (R2 = 0.92, P = 0.0002, bias 4.4%), and energy per ejected volume (R2 = 0.89, P = 0.0001, bias 3.7%). Variations in estimated end-diastolic pressure did not significantly affect results (P > 0.05 for all). Intraobserver analysis after one year demonstrated 0.9–3.4% bias for LV volumetry and 0.2–5.4% for PV loop-derived parameters.

Conclusion

Pressure-volume loops can be precisely and accurately computed from CMR imaging and brachial cuff blood pressure in humans.
Clinical implementation of partial oral treatment in infective endocarditis: the Danish POETry study
Authors: Pries-Heje Mia Marie , Hjulmand Julie Glud , Lenz Ingrid Try , Hasselbalch Rasmus Bo , Povlsen Jonas Agerlund , Ihlemann Nikolaj , Køber Nana , Tofterup Marlene Lyngborg , Østergaard Lauge , Dalsgaard Morten , Faurholt-Jepsen Daniel , Wienberg Malene , Christiansen Ulrik , Bruun Niels Eske , Fosbøl Emil , Moser Claus , Iversen Kasper Karmark , Bundgaard Henning
Published: October 2023

Background and Aims

In the Partial Oral Treatment of Endocarditis (POET) trial, stabilized patients with left-sided infective endocarditis (IE) were randomized to oral step-down antibiotic therapy (PO) or conventional continued intravenous antibiotic treatment (IV), showing non-inferiority after 6 months. In this study, the first guideline-driven clinical implementation of the oral step-down POET regimen was examined.

Methods

Patients with IE, caused by Staphylococcus aureus, Enterococcus faecalis, Streptococcus spp. or coagulase-negative staphylococci diagnosed between May 2019 and December 2020 were possible candidates for initiation of oral step-down antibiotic therapy, at the discretion of the treating physician. The composite primary outcome in patients finalizing antibiotic treatment consisted of embolic events, unplanned cardiac surgery, relapse of bacteraemia and all-cause mortality within 6 months.

Results

A total of 562 patients [median age 74 years (IQR, interquartile range, 65–80), 70% males] with IE were possible candidates; PO was given to 240 (43%) patients and IV to 322 (57%) patients. More patients in the IV group had IE caused by S. aureus, or had an intra-cardiac abscess, or a pacemaker and more were surgically treated. The primary outcome occurred in 30 (13%) patients in the PO group and in 59 (18%) patients in the IV group (P = .051); in the PO group, 20 (8%) patients died vs. 46 (14%) patients in the IV group (P = .024). PO-treated patients had a shorter median length of stay [PO 24 days (IQR 17–36) vs. IV 43 days (IQR 32–51), P < .001].

Conclusions

After clinical implementation of the POET regimen almost half of the possible candidates with IE received oral step-down antibiotic therapy. Patients in the IV group had more serious risk factors for negative outcomes. At 6-month follow-up, there was a numerically but not statistically significant difference towards a lower incidence of the primary outcome, a lower incidence of all-cause mortality and a reduced length of stay in the PO group. Due to the observational design of the study, the lower mortality may to some extent reflect selection bias and unmeasured confounding. Clinical implementation of PO regimens seemed feasible and safe.
Comparison of non-laser and laser transvenous lead extraction: a systematic review and meta-analysis
Authors: Akhtar Zaki , Kontogiannis Christos , Georgiopoulos Georgios , Starck Christoph T , Leung Lisa W M , Lee Sun Y , Lee Byron K , Seshasai Sreenivasa R K , Sohal Manav , Gallagher Mark M
Published: October 2023

Aims

Transvenous lead extraction (TLE) is performed using non-laser and laser techniques with overall high efficacy and safety. Variation in outcomes between the two approaches does exist with limited comparative evidence in the literature. We sought to compare non-laser and laser TLE in a meta-analysis.

Methods and results

We searched Medline, Embase, Scopus, ClinicalTrials.gov, and CENTRAL databases for TLE studies published between 1991 and 2021. From the included 68 studies, safety and efficacy data were carefully evaluated and extracted. Aggregated cases of outcomes were used to calculate odds ratio (OR), and pooled rates were synthesized from eligible studies to compare non-laser and laser techniques. Subgroup comparison of rotational tool and laser extraction was also performed. Non-laser in comparison with laser had lower procedural mortality (pooled rate 0% vs. 0.1%, P < 0.01), major complications (pooled rate 0.7% vs. 1.7%, P < 0.01), and superior vena cava (SVC) injury (pooled rate 0% vs. 0.5%, P < 0.001), with higher complete success (pooled rate 96.5% vs. 93.8%, P < 0.01). Non-laser comparatively to laser was more likely to achieve clinical [OR 2.16 (1.77–2.63), P < 0.01] and complete [OR 1.87 (1.69–2.08), P < 0.01] success, with a lower procedural mortality risk [OR 1.6 (1.02–2.5), P < 0.05]. In the subgroup analysis, rotational tool compared with laser achieved greater complete success (pooled rate 97.4% vs. 95%, P < 0.01) with lower SVC injury (pooled rate 0% vs. 0.7%, P < 0.01).

Conclusion

Non-laser TLE is associated with a better safety and efficacy profile when compared with laser methods. There is a greater risk of SVC injury associated with laser sheath extraction.
Pseudomonas aeruginosa biofilm exopolysaccharides: assembly, function, and degradation
Authors: Gheorghita Andreea A , Wozniak Daniel J , Parsek Matthew R , Howell P Lynne
Published: October 2023

The biofilm matrix is a fortress; sheltering bacteria in a protective and nourishing barrier that allows for growth and adaptation to various surroundings. A variety of different components are found within the matrix including water, lipids, proteins, extracellular DNA, RNA, membrane vesicles, phages, and exopolysaccharides. As part of its biofilm matrix, Pseudomonas aeruginosa is genetically capable of producing three chemically distinct exopolysaccharides – alginate, Pel, and Psl – each of which has a distinct role in biofilm formation and immune evasion during infection. The polymers are produced by highly conserved mechanisms of secretion, involving many proteins that span both the inner and outer bacterial membranes. Experimentally determined structures, predictive modelling of proteins whose structures are yet to be solved, and structural homology comparisons give us insight into the molecular mechanisms of these secretion systems, from polymer synthesis to modification and export. Here, we review recent advances that enhance our understanding of P. aeruginosa multiprotein exopolysaccharide biosynthetic complexes, and how the glycoside hydrolases/lyases within these systems have been commandeered for antimicrobial applications.
“Terror Is a Better Word”: A Qualitative Analysis of Dementia-Related Anxiety
Authors: Maxfield Molly , Peckham Allie , James Dara L
Published: October 2023

Background and Objectives

Dementia-related anxiety (DRA) is the fear of a current or future diagnosis of Alzheimer’s disease or another type of dementia. Previous studies suggest diverse factors contribute to DRA, including emotional, social, and cognitive concerns. A mixed-methods investigation was designed to explore DRA’s underlying causes; we present a thematic analysis of these causes.

Research Design and Methods

A semistructured qualitative interview design was used to explore participant’s thoughts, feelings, and reactions about dementia. Fifty community-dwelling adults (aged 58–89, M = 70.80, SD = 6.02) without dementia diagnoses were interviewed, with a focus on why dementias are anxiety-provoking diagnoses. We engaged in a reflexive inductive thematic approach.

Results

We identified 7 themes positioned within previously established antecedents of DRA. Anticipated consequences were conveyed in statements identifying dementia as a feared diagnosis and its connection to how one would be treated if diagnosed. Low perceived control was associated with dementia’s anticipated effects including the ability of dementia to undermine core aspects of one’s personhood, limit independence, and increase reliance on others. Perceived risk was connected to past familial experiences with dementia and the implications of receiving different diagnoses with different trajectories and treatments.

Discussion and Implications

Findings offer insight into diverse factors contributing to DRA, which can be used to inform public health messaging and develop applicable and clinically relevant interventions to meet the needs of individuals experiencing DRA and their social support systems.
Computational prediction of human deep intronic variation
Authors: Barbosa Pedro , Savisaar Rosina , Carmo-Fonseca Maria , Fonseca Alcides
Published: October 2023

Background

The adoption of whole-genome sequencing in genetic screens has facilitated the detection of genetic variation in the intronic regions of genes, far from annotated splice sites. However, selecting an appropriate computational tool to discriminate functionally relevant genetic variants from those with no effect is challenging, particularly for deep intronic regions where independent benchmarks are scarce.

Results

In this study, we have provided an overview of the computational methods available and the extent to which they can be used to analyze deep intronic variation. We leveraged diverse datasets to extensively evaluate tool performance across different intronic regions, distinguishing between variants that are expected to disrupt splicing through different molecular mechanisms. Notably, we compared the performance of SpliceAI, a widely used sequence-based deep learning model, with that of more recent methods that extend its original implementation. We observed considerable differences in tool performance depending on the region considered, with variants generating cryptic splice sites being better predicted than those that potentially affect splicing regulatory elements. Finally, we devised a novel quantitative assessment of tool interpretability and found that tools providing mechanistic explanations of their predictions are often correct with respect to the ground - information, but the use of these tools results in decreased predictive power when compared to black box methods.

Conclusions

Our findings translate into practical recommendations for tool usage and provide a reference framework for applying prediction tools in deep intronic regions, enabling more informed decision-making by practitioners.
Urgent need for substance use disorder research among understudied populations: examining the Asian-American experience
Authors: Choi Sugy , Lim Sahnah , Kwon Simona C , Trinh-Shevrin Chau , Neighbors Charles J , Yi Stella S
Published: October 2023

Substance use disorder (SUD) among Asian Americans is understudied. Our review of National Institutes of Health–funded projects reveals a striking underrepresentation of research focused on SUD in this population, possibly perpetuated by the pervasive societal myth that Asian Americans are a healthy community. Moreover, the limited availability and disaggregation of data on SUD among Asian Americans further hinder our understanding of prevalence rates, treatment utilization, and associated disparities—thereby limiting opportunities for prevention and intervention. In light of these findings, our review serves as a crucial call to action, emphasizing the urgent need for increased research efforts and resources to address the significant gaps in knowledge and inform effective interventions for addressing SUD among Asian Americans.
The C-terminal extension of dyskerin is a dyskeratosis congenita mutational hotspot that modulates interaction with telomerase RNA and subcellular localization
Authors: Qin Jian , Garus Alexandre , Autexier Chantal
Published: October 2023

Dyskerin is a component of the human telomerase complex and is involved in stabilizing the human telomerase RNA (hTR). Many mutations in the DKC1 gene encoding dyskerin are found in X-linked dyskeratosis congenita (X-DC), a premature aging disorder and other related diseases. The C-terminal extension (CTE) of dyskerin contributes to its interaction with the molecular chaperone SHQ1 during the early stage of telomerase biogenesis. Disease mutations in this region were proposed to disrupt dyskerin-SHQ1 interaction and destabilize dyskerin, reducing hTR levels indirectly. However, biochemical evidence supporting this hypothesis is still lacking. In addition, the effects of many CTE disease mutations on hTR have not been examined. In this study, we tested eight dyskerin CTE variants and showed that they failed to maintain hTR levels. These mutants showed slightly reduced but not abolished interaction with SHQ1, and caused defective binding to hTR. Deletion of the CTE further reduced binding to hTR, and perturbed localization of dyskerin to the Cajal bodies and the nucleolus, and the interaction with TCAB1 as well as GAR1. Our findings suggest impaired dyskerin-hTR interaction in cells as a previously overlooked mechanism through which dyskerin CTE mutations cause X-DC and related telomere syndromes.