bluuebunny/crossref_metadata_2025 huggingface dataset:
In situ cell-scale probing nucleation, growth and evolution of CsPbBr3 nanowires by optical absorption spectroscopy
Authors: Bai Yan , Wu Heqian , Wang Dengke , Liu Mei , Lu Zheng-Hong , Ding Huaiyi
Published: April 2024

The growth kinetics of colloidal lead halide perovskite nanomaterials are an integral part of their applications, remains poorly understood due to complex nucleation processes and lack of in situ size monitoring method. Here we demonstrated that absorption spectra can be used to observe in situ growth processes of ultrathin CsPbBr3 nanowires in solution with reference to the effective mass infinite deep square potential well model. By means of this method, we have found that the ultrathin nanowires, fabricated by hot injection method, were firstly formed within one minute. Subsequently, they merge with each other into a thicker structure with increasing reaction time. We revealed that the nucleation, growth, and merging of the CsPbBr3 nanowires are determined by the acid concentration and ligand chain length. At lower acidity, the critical nucleation size of the nanowire is smaller, while the shorter the ligand chain length, the faster the merging among the nanowires. Moreover, the merging mode between nanowires changed with their nucleation size. This growth kinetics of CsPbBr3 nanowires provides a reference for optimizing the synthesis conditions to obtain the one-dimensional CsPbBr3 with desired size, thus enabling accurate control of the nanowire shape.
Optimizing the performance of silica nanoparticles functionalized with a near-infrared fluorescent dye for bioimaging applications
Authors: Ehrhorn Evie G , Lovell Paul , Svechkarev Denis , Romanova Svetlana , Mohs Aaron M
Published: April 2024

Modified fluorescent nanoparticles continue to emerge as promising candidates for drug delivery, bioimaging, and labeling tools for various biomedical applications. The ability of nanomaterials to fluorescently label cells allow for the enhanced detection and understanding of diseases. Silica nanoparticles have a variety of unique properties that can be harnessed for many different applications, causing their increased popularity. In combination with an organic dye, fluorescent nanoparticles demonstrate a vast range of advantageous properties including long photostability, surface modification, and signal amplification, thus allowing ease of manipulation to best suit bioimaging purposes. In this study, the Stöber method with tetraethyl orthosilicate (TEOS) and a fluorescent dye sulfo-Cy5-amine was used to synthesize fluorescent silica nanoparticles. The fluorescence spectra, zeta potential, quantum yield, cytotoxicity, and photostability were evaluated. The increased intracellular uptake and photostability of the dye-silica nanoparticles show their potential for bioimaging.
Investigation of electronic, ferroelectric and local electrical conduction behavior of RF sputtered BiFeO3 thin films
Authors: Hussain Shahzad , Awan Saif Ullah , Mumtaz Arif , Siddique Resham , Aftab Muhammad , Hasanain S K
Published: April 2024

Most of the applied research on BiFeO3 (BFO) focuses on magnetoelectric and spintronic applications. This calls for a detailed grasp of multiferroic and conduction properties. BFO thin films with (100) epitaxial growth has been deposited on a LaNiO3 (LNO) buffered Pt/Ti/SiO2/Si(100) substrate using RF magnetron sputtering. The film formed at 15 mTorr, 570 °C, and with Ar/O2 4:1 had a reasonably high degree of (100)-preferential orientation, the least surface roughness, and a densely packed structure. We obtained ferroelectric loops with strong polarization (150 μC cm−2). The leakage current density is as low as 10–2 A cm−2 at 100 kV cm−1, implying that space-charge-limited bulk conduction (SCLC) was the primary conduction channel for carriers within BFO films. Local electrical conduction behavior demonstrates that at lower voltages, the grain boundary dominates electrical conduction and is linked to the displacement of oxygen vacancies in the grain boundary under external electric fields. We hope that a deeper understanding of the conduction mechanism will help integrate BFO into viable technologies.
The respective and dependent effects of scattering and bone matrix absorption on ultrasound attenuation in cortical bone
Authors: McCandless Brett Austin , Raum Kay , Muller Marie
Published: April 2024

Cortical bone is characterized by a dense solid matrix permeated by fluid-filled pores. Ultrasound scattering has potential for the non-invasive evaluation of changes in bone porosity. However, there is an incomplete understanding of the impact of ultrasonic absorption in the solid matrix on ultrasound scattering. In this study, maps were derived from scanning acoustic microscopy images of human femur cross-sections. Finite-difference time domain ultrasound scatter simulations were conducted on these maps. Pore density, diameter distribution of the pores, and nominal absorption values in the solid and fluid matrices were controlled. Ultrasound pulses with a central frequency of 8.2 MHz were propagated, both in through-transmission and backscattering configurations. From these data, the scattering, bone matrix absorption, and attenuation extinction lengths were calculated. The results demonstrated that as absorption in the solid matrix was varied, the scattering, absorption, and attenuation extinction lengths were significantly impacted. It was shown that for lower values of absorption in the solid matrix (less than 2 dB mm−1), attenuation due to scattering dominates, whereas at higher values of absorption (more than 2 dB mm−1), attenuation due to absorption dominates. This will impact how ultrasound attenuation and scattering parameters can be used to extract quantitative information on bone microstructure.
Phase contrast micro-CT with adjustable in-slice spatial resolution at constant magnification
Authors: Zekavat Amir Reza , Lioliou Grammatiki , Roche i Morgó Oriol , Maughan Jones Charlotte , Galea Gabriel , Maniou Eirini , Doherty Adam , Endrizzi Marco , Astolfo Alberto , Olivo Alessandro , Hagen Charlotte
Published: April 2024

Objective. To report on a micro computed tomography (micro-CT) system capable of x-ray phase contrast imaging and of increasing spatial resolution at constant magnification. Approach. The micro-CT system implements the edge illumination (EI) method, which relies on two absorbing masks with periodically spaced transmitting apertures in the beam path; these split the beam into an array of beamlets and provide sensitivity to the beamlets’ directionality, i.e. refraction. In EI, spatial resolution depends on the width of the beamlets rather than on the source/detector point spread function (PSF), meaning that resolution can be increased by decreasing the mask apertures, without changing the source/detector PSF or the magnification. Main results. We have designed a dedicated mask featuring multiple bands with differently sized apertures and used this to demonstrate that resolution is a tuneable parameter in our system, by showing that increasingly small apertures deliver increasingly detailed images. Phase contrast images of a bar pattern-based resolution phantom and a biological sample (a mouse embryo) were obtained at multiple resolutions. Significance. The new micro-CT system could find application in areas where phase contrast is already known to provide superior image quality, while the added tuneable resolution functionality could enable more sophisticated analyses in these applications, e.g. by scanning samples at multiple scales.
Effect of traps on carrier transport in CdSe quantum dot thin films
Authors: Zheng Fuzhong , Li Zhonghao , Huang Bo , Zhu Hongbing , Wu Ying
Published: April 2024

The influence of trap effects on carrier transport characteristics in quantum dot (QD) thin films is the subject of study, aiming to provide a theoretical basis for the structural design and performance improvement of QD thin film optoelectronic devices. This study presents a specific mathematical description of capturing and releasing charges by traps, which includes the time-varying equation for captured charges. Utilizing the carrier hopping transport model, a system of partial differential equations is employed as the physical field, establishing hopping transport models that account for both shallow traps and a combination of shallow and deep traps. Simulations based on specific experimental samples reveal that the presence of traps introduces asymmetry in the diffusion motion of charge carriers, extending the duration of the photocurrent signal and resulting in the capture of charges, along with a reduction in the peak value of the current signal. The model also simulates carrier transport characteristics under the influence of repetitive light pulses, demonstrating distinct patterns in capturing and releasing charges for both shallow and deep traps.
Discriminatory resonance energy transfer mediated by a chiral environment
Authors: Franz Janine C , Yoshi Buhmann Stefan , Salam A
Published: April 2024

In this study, we delve into the crucial influence of and enhancement by chiral environments on the discriminatory capabilities of resonance energy transfer. Firstly, we scrutinize the impact of a macroscopic chiral medium enveloping the interacting molecules; secondly, we probe the effect of a chiral mediating molecule in close proximity to the system. Importantly, our findings demonstrate that chiral environments not only modulate pre-existing discriminatory effects but also introduce novel mechanisms for discrimination. Central to our research is the application of an innovative model for chiral local-field corrections, which unveils a remarkable distance-dependent inversion of the discrimination dynamics. Our study extends beyond the confines of any specific molecular system, offering a comprehensive discussion of these diverse effects, thereby providing insights with broader implications. Finally, we present a comparative analysis across all studied systems, illustrating our insights by employing 3-methyl-cyclopentanone as an example molecule.
Impact resistance analysis of a dual-constituent negative Poisson’s ratio lattice metamaterial with tailorable coefficient of thermal expansion
Authors: Dong Yanzhang , Li Qingfeng , Cui Feidie , Bai Liang , Xu Weikai
Published: April 2024

The combination of parameters such as negative Poisson’s ratio (NPR) and negative coefficient of thermal expansion (NCTE) can result in novel materials with specialized functions to meet the requirements of multifunctional and multipurpose devices. However, the additional structural design to meet NCTE requires a re-examination of its impact resistance. In this paper, the deformation modes and impact resistance of dual-constituent re-entrant hexagonal lattice metamaterial (DRHLM) with both NPR and NCTE are investigated under different impact velocities, and the nominal stress–strain curves and energy absorption characteristics of DRHLM structures with different arch heights, chord lengths, and angles of the bottom edge ribs and the diagonal ribs are discussed. The results show that the bi-material bending ribs affect the energy absorption of the structure, and in most cases the DRHLM structure has a better energy absorption capacity than the traditional concave hexagonal structure, but too much or too little curvature of the bi-material portion reduces the energy absorption characteristics of the DRHLM structure. In addition, the increase in the pinch angle of the ribs leads to the weakening of the negative Poisson’s ratio effect, which is also detrimental to the energy absorption of the structure. The work done can provide guidance for finding the dimensional parameters of DRHLM structures with optimal energy absorption performance.
The guiding center role in defining the eigenstates of an electron in the fractional quantum Hall effect regime: ladder operators approach
Authors: Bentalha Z
Published: April 2024

The quantum problem of a two-dimensional electron in a uniform perpendicular magnetic field is considered. Using the formalism of ladder operators, the electron eigenfunctions are derived for all quantum numbers n and m, where n denotes the Landau level and m the eigenvalue of the angular momentum L

z
, with m taking all possible eigenvalues. We note that existing one-electron orbitals, in most of the known literature on the fractional quantum Hall effect (FQHE), correspond to a restricted range of possible eigenvalues m, some are missing. Similarly detailed calculations using ladder operator techniques show that for a state ∣n, m〉, the quantum number (n − m) represents a precise physical quantity, that is the distance from the origin to the center of the electron orbit. This finding allowed us to obtain, for this known quantum problem, a new set of basis states for which both quantum numbers have a physical meaning namely n and (n − m).
Dynamic PB metasurface for transmissive and reflective wavefront manipulation
Authors: Wang Yihan , Li Chunhui , Niu Junhao
Published: April 2024

Based on the phase transition characteristics of vanadium dioxide (changes in conductivity with temperature), we designed a dynamic metasurface for wavefront manipulation that can switch between transmission and reflection modes at the same frequency. When vanadium dioxide is in the metallic state, the metasurface operates in reflection mode, while it is in the insulating state, it works in transmission mode. The phase distributions of the two operating modes are different and can be easily adjusted by rotating the inner and outer rings. At the frequency of 1.3 THz, we designed a metasurface that can switch between anomalous reflection and refraction with different deflection angles. Additionally, we created a switchable metalens that provides different focal lengths in reflection and transmission modes. The tunable metasurface can provide innovative design possibilities for dynamical wavefront manipulation.
Amplifying the nonlinear optical response of sunflower-like C16S8 through superhalogen doping
Authors: Kosar Naveen , Ashraf Tayyba , Imran Muhammad , Mahmood Tariq
Published: April 2024

Superhalogens, known for their higher electron affinity compared to halogens, exhibit a unique ability to accept electrons from any electron donor specie. Leveraging this property, the doping of superhalogens onto electron-rich surfaces has emerged as a potent approach to augment nonlinear optical (NLO) response. Herein, we investigated the doping of beryllium trifluoride (BeF3), calcium trifluoride (CaF3) and magnesium trifluoride (MgF3) superhalogens on thia[8]circulene (C16S8) sunflower through density functional theory (DFT) calculations, to observe the improvement in the NLO response of resultant complexes. The study explores the thermal stability of complexes through interaction energy analysis, revealing robust structural properties. Conducting properties of the resultant complexes are examined via frontier molecular orbitals (FMOs) analysis, demonstrating notable changes. Molecular electrostatic potential (MEP) and Fukui function analyses gave an idea about the reactivity of the pure C16S8 and superhalogen doped C16S8 complexes. To quantify the NLO response, we assessed the first hyperpolarizability (β
o) via comprehensive analysis. Remarkably, the MgF3@C16S8 complex reflects the highest hyperpolarizability value (1.85 × 104 au), signifying its exceptional NLO enhancement potential. Ultra-violet visible (UV–vis) analysis illustrated the increase in the wavelengths (red shift) of C16S8 complexes after doping of superhalogen. To elucidate the underlying factors contributing to the improved NLO response, a rationalization is provided through a two-level model.
Dynamics of multicavity hyperchaotic maps with rotational control operation and its applications
Authors: Zhu Wanting , Sun Kehui , Li Binglun , Wang Huihai
Published: April 2024

To provide more complex and random chaotic maps to applications and algorithms, we propose a boundary coupled modulation (BCM) model. By introducing the rotation-matrix (ROT), the corresponding rotation boundary coupled modulation (RBCM) model are constructed, and a series of hyperchaotic maps are generated with various attractors and numerous fixed points. The shape and size of the multicavity can be adjusted by controlling the parameters. Interestingly, RBCM maps are controlled by changing rotation coefficients (Rot-C, d, e, and θ), which can rotate the attractor of the enhanced BCM at any angle and direction. RBCM maps produce a more uniform topological space, and have multiple pairs of symmetric coexisting attractors. The BCM and RBCM maps exhibit rich dynamical behaviors, high complexity, and strong randomness.To verify the engineering practicability, we apply the BCM and RBCM maps to design pseudo-random number generators (PRNG), and test it with NIST, quadrature amplitude modulation (QAM) system. Finally, the FPGA implementation of the proposed chaotic map verifies.
Quaternion form of the electromagnetic reciprocity theorem
Authors: Liu Guoqiang , Li Yuanyuan , Liu Jing
Published: April 2024

In this paper, the general forms of quaternion electromagnetic field mutual energy-momentum equations (QEMF-MEME) and quaternion electromagnetic field energy-momentum reciprocal equations (QEMF-EMRE) in frequency domain are derived based on the quaternion-electromagnetic-field equations. It has been discovered that QEMF- EMRE is a reflection of the electromagnetic interaction between lagging and leading waves. The real and imaginary parts of scalar, the real and imaginary parts of vector of QEMF-EMRE correspond to the Feld-Tai reciprocity theorem, Lorentz reciprocity theorem, and the two sets of momentum reciprocity theorems, respectively. While, QEMF-MEME reflects the electromagnetic interaction of two sets of lagging waves, and its real scalar, imaginary scalar, real-vector, and imaginary-vector parts are the Feld-Tai reciprocal energy theorem, the reciprocal energy theorem, the two sets of reciprocal momentum theorem.
Hydrogen Epoch of Reionization Array (HERA) Phase II Deployment and Commissioning
Authors: Berkhout Lindsay M. , Jacobs Daniel C. , Abdurashidova Zuhra , Adams Tyrone , Aguirre James E. , Alexander Paul , Ali Zaki S. , Baartman Rushelle , Balfour Yanga , Beardsley Adam P. , Bernardi Gianni , Billings Tashalee S. , Bowman Judd D. , Bradley Richard F. , Bull Philip , Burba Jacob , Byrne Ruby , Carey Steven , Carilli Chris L. , Chen Kai-Feng , Cheng Carina , Choudhuri Samir , DeBoer David R. , de Lera Acedo Eloy , Dexter Matt , Dillon Joshua S. , Dynes Scott , Eksteen Nico , Ely John , Ewall-Wice Aaron , Fagnoni Nicolas , Fritz Randall , Furlanetto Steven R. , Gale-Sides Kingsley , Garsden Hugh , Gehlot Bharat Kumar , Ghosh Abhik , Glendenning Brian , Gorce Adelie , Gorthi Deepthi , Greig Bradley , Grobbelaar Jasper , Halday Ziyaad , Hazelton Bryna J. , Hewitt Jacqueline N. , Hickish Jack , Huang Tian , Josaitis Alec , Julius Austin , Kariseb MacCalvin , Kern Nicholas S. , Kerrigan Joshua , Kim Honggeun , Kittiwisit Piyanat , Kohn Saul A. , Kolopanis Matthew , Lanman Adam , La Plante Paul , Liu Adrian , Loots Anita , Ma Yin-Zhe , Edward MacMahon David Harold , Malan Lourence , Malgas Cresshim , Malgas Keith , Marero Bradley , Martinot Zachary E. , Mesinger Andrei , Molewa Mathakane , Morales Miguel F. , Mosiane Tshegofalang , Murray Steven G. , Neben Abraham R. , Nikolic Bojan , Nunhokee Chuneeta Devi , Nuwegeld Hans , Parsons Aaron R. , Pascua Robert , Patra Nipanjana , Pieterse Samantha , Qin Yuxiang , Rath Eleanor , Razavi-Ghods Nima , Riley Daniel , Robnett James , Rosie Kathryn , Santos Mario G. , Sims Peter , Singh Saurabh , Storer Dara , Swarts Hilton , Tan Jianrong , Thyagarajan Nithyanandan , van Wyngaarden Pieter , Williams Peter K. G. , Zheng Haoxuan , Xu Zhilei
Published: April 2024

This paper presents the design and deployment of the Hydrogen Epoch of Reionization Array (HERA) phase II system. HERA is designed as a staged experiment targeting 21 cm emission measurements of the Epoch of Reionization. First results from the phase I array are published as of early 2022, and deployment of the phase II system is nearing completion. We describe the design of the phase II system and discuss progress on commissioning and future upgrades. As HERA is a designated Square Kilometre Array pathfinder instrument, we also show a number of “case studies” that investigate systematics seen while commissioning the phase II system, which may be of use in the design and operation of future arrays. Common pathologies are likely to manifest in similar ways across instruments, and many of these sources of contamination can be mitigated once the source is identified.
Can the late dark energy parameterization reconcile the Hubble tension?*
Authors: Zhang 张 Ming-Jian 明建 , Chen 陈 Li 丽 , Yang 杨 Maoyou 茂友 , Wang 王 Junmei 俊美
Published: April 2024

In this study, we constructed ten dark energy models to test whether they can reconcile the Hubble tension and how much it is affected by parameterization. To establish a fair test, the models are diverse, encompassing fractional, logarithmic, exponential, and inverse exponential forms as well as several non-parameterized models. The dataset we used includes the NPIPE pipeline of cosmic microwave background (CMB) power-spectrum data from Planck2020, Pantheon+ samples from Supernovae Type Ia, and baryon acoustic oscillations. The MCMC calculations imply dark energy transferring from

to

for the four parameterized dark energy models. However, these models cannot adequately reconcile the Hubble tension. Notably, we found that phantom-like dark energy with

can achieve the greatest reduction in the Hubble tension to

. However, AIC analysis indicates that this alleviation is at the cost of high AIC. We also investigated the effect of constructions on the derivative of the equation of state

, cosmic density parameter, CMB power spectrum

, and matter spectra

. We also found that the Hubble tension may be related to the reionization process.
A two-layer single shell magnetized target for lessening the Nernst effect
Authors: Chen Shijia , Wu Fuyuan , Zhang Hua , Zhou Cangtao , Ma Yanyun , Ramis Rafael
Published: April 2024

Fuel magnetization significantly lowers the required radial convergence, enabling cylindrical implosions to become a promising approach for inertial confinement fusion. The Nernst effect on the two-layer single shell magnetized target design applied to a Z-pinch benefits from a gold layer that decreases fuel demagnetization and serves as a magnetothermal insulation layer, preventing magnetothermal losses. The resistive diffusion and Nernst advection of the magnetic field are considered in the radiation magnetohydrodynamic model, which alter the evolution of magnetic flux in the magnetized target and result in plasma demagnetization. The results demonstrate that targets with a wide range of parameters can achieve ignition conditions under a 30 MA driven current. A two-layer single shell magnetized target for lessening the Nernst effect has the potential to achieve ignition conditions. The fusion yield of the optimal target increases by 168% from 0.71 MJ to 1.90 MJ, compared to a one-layer single shell target.
Variable selection when estimating effects in external target populations
Authors: Webster-Clark Michael , Ross Rachael K , Keil Alexander P , Platt Robert W
Published: April 2024

External validity is an important part of epidemiologic research. To validly estimate effects in specific external target populations using a chosen effect measure (ie, “transport”), some methods require that one account for all effect measure modifiers (EMMs). However, little is known about how including other variables that are not EMMs (ie, non-EMMs) in adjustment sets affects estimates. Using simulations, we evaluated how inclusion of non-EMMs affected estimation of the transported risk difference (RD) by assessing the impacts of covariates that (1) differ (or not) between the trial and the target, (2) are associated with the outcome (or not), and (3) modify the RD (or not). We assessed variation and bias when covariates with each possible combination of these factors were used to transport RDs using outcome modeling or inverse odds weighting. Inclusion of variables that differed in distribution between the populations but were non-EMMs reduced precision, regardless of whether they were associated with the outcome. However, non-EMMs associated with selection did not amplify bias resulting from omission of necessary EMMs. Including all variables associated with the outcome may result in unnecessarily imprecise estimates when estimating treatment effects in external target populations.
Sexual conflict and social networks in bed bugs: effects of social experience
Authors: Yan Janice L , Rosenbaum Jack R , Esteves Selena , Dobbin Maggie L , Dukas Reuven
Published: April 2024

Living in groups can provide essential experience that improves sexual performance and reproductive success. While the effects of social experience have drawn considerable scientific interest, commonly used behavioral assays often do not capture the dynamic nature of interactions within a social group. Here, we conducted 3 experiments using a social network framework to test whether social experience during early adulthood improves the sexual competence of bed bugs (Cimex lectularius) when placed in a complex and competitive group environment. In each experiment, we observed replicate groups of bed bugs comprising previously socialized and previously isolated individuals of the same sex, along with an equal number of standardized individuals of the opposite sex. Regardless of whether we controlled for their insemination history, previously isolated males mounted and inseminated females at significantly higher rates than previously socialized males. However, we found no evidence of social experience influencing our other measures of sexual competence: proportion of mounts directed at females, ability to overcome female resistance, and strength of opposite-sex social associations. We similarly did not detect effects of social experience on our female sexual competence metrics: propensity to avoid mounts, rate of successfully avoiding mounts, opposite-sex social association strength, and rate of receiving inseminations. Our findings indicate that early social experience does not improve sexual competence in male and female bed bugs.
AbLEF: antibody language ensemble fusion for thermodynamically empowered property predictions
Authors: Rollins Zachary A , Widatalla Talal , Waight Andrew , Cheng Alan C , Metwally Essam
Published: April 2024

Motivation

Pre-trained protein language and/or structural models are often fine-tuned on drug development properties (i.e. developability properties) to accelerate drug discovery initiatives. However, these models generally rely on a single structural conformation and/or a single sequence as a molecular representation. We present a physics-based model, whereby 3D conformational ensemble representations are fused by a transformer-based architecture and concatenated to a language representation to predict antibody protein properties. Antibody language ensemble fusion enables the direct infusion of thermodynamic information into latent space and this enhances property prediction by explicitly infusing dynamic molecular behavior that occurs during experimental measurement.

Results

We showcase the antibody language ensemble fusion model on two developability properties: hydrophobic interaction chromatography retention time and temperature of aggregation (Tagg). We find that (i) 3D conformational ensembles that are generated from molecular simulation can further improve antibody property prediction for small datasets, (ii) the performance benefit from 3D conformational ensembles matches shallow machine learning methods in the small data regime, and (iii) fine-tuned large protein language models can match smaller antibody-specific language models at predicting antibody properties.

Availability and implementation

AbLEF codebase is available at https://github.com/merck/AbLEF.
Formation process of organic–inorganic layered hybrid materials from vacuum-deposited bilayer thin films of CH3(CH2)11NH3I and SnI2 by post-annealing
Authors: Abe Ren , Maruyama Shingo , Kaminaga Kenichi , Matsumoto Yuji
Published: April 2024

We investigated the formation process of Sn-based 2D organic–inorganic layered hybrid materials from sequentially vacuum-deposited bilayer thin films of CH3(CH2)11NH3I (DDAI) and SnI2 by post-annealing. DDA2SnI4 or DDASnI3 was selectively formed depending on the DDAI/ SnI2 molar ratio and the annealing temperature. It was revealed that DDASnI3 is formed via the phase transformation of DDA2SnI4 that has been formed at a low temperature from a SnI2-rich bilayer thin film by a temperature increase.
Successful Treatment of Carbapenem-Resistant Acinetobacter baumannii Meningitis With Sulbactam-Durlobactam
Authors: Tamma Pranita D , Immel Shanan , Karaba Sara M , Soto Caitlin L , Conzemius Rick , Gisriel Emily , Tekle Tsigereda , Stambaugh Haley , Johnson Emily , Tornheim Jeffrey A , Simner Patricia J
Published: April 2024

Background

The treatment of carbapenem-resistant Acinetobacter baumannii/calcoaceticus complex (CRAB) presents significant treatment challenges.

Methods

We report the case of a 42-year-old woman with CRAB meningitis who experienced persistently positive cerebrospinal fluid (CSF) cultures for 13 days despite treatment with high-dose ampicillin-sulbactam and cefiderocol. On day 13, she was transitioned to sulbactam-durlobactam and meropenem; 4 subsequent CSF cultures remained negative. After 14 days of sulbactam-durlobactam, she was cured of infection. Whole genome sequencing investigations identified putative mechanisms that contributed to the reduced cefiderocol susceptibility observed during cefiderocol therapy. Blood and CSF samples were collected pre-dose and 3-hours post initiation of a sulbactam-durlobactam infusion.

Results

The CRAB isolate belonged to sequence type 2. An acquired blaOXA-23 and an intrinsic blaOXA-51-like (ie, blaOXA-66) carbapenemase gene were identified. The paradoxical effect (ie, no growth at lower cefiderocol dilutions but growth at higher dilutions) was observed by broth microdilution after 8 days of cefiderocol exposure but not by disk diffusion. Potential markers of resistance to cefiderocol included mutations in the start codon of piuA and piuC iron transport genes and an A515V substitution in PBP3, the primary target of cefiderocol. Sulbactam and durlobactam were detected in CSF at both timepoints, indicating CSF penetration.

Conclusions

This case describes successful treatment of refractory CRAB meningitis with the administration of sulbactam-durlobactam and meropenem and highlights the need to be cognizant of the paradoxical effect that can be observed with broth microdilution testing of CRAB isolates with cefiderocol.
Application of machine learning in the preoperative radiomic diagnosis of ameloblastoma and odontogenic keratocyst based on cone-beam CT
Authors: Song Yang , Ma Sirui , Mao Bing , Xu Kun , Liu Yuan , Ma Jingdong , Jia Jun
Published: April 2024

Objectives

Preoperative diagnosis of oral ameloblastoma (AME) and odontogenic keratocyst (OKC) has been a challenge in dentistry. This study uses radiomics approaches and machine learning (ML) algorithms to characterize cone-beam CT (CBCT) image features for the preoperative differential diagnosis of AME and OKC and compares ML algorithms to expert radiologists to validate performance.

Methods

We retrospectively collected the data of 326 patients with AME and OKC, where all diagnoses were confirmed by histopathologic tests. A total of 348 features were selected to train six ML models for differential diagnosis by a 5-fold cross-validation. We then compared the performance of ML-based diagnoses to those of radiologists.

Results

Among the six ML models, XGBoost was effective in distinguishing AME and OKC in CBCT images, with its classification performance outperforming the other models. The mean precision, recall, accuracy, F1-score, and area under the curve (AUC) were 0.900, 0.807, 0.843, 0.841, and 0.872, respectively. Compared to the diagnostics by radiologists, ML-based radiomic diagnostics performed better.

Conclusions

Radiomic-based ML algorithms allow CBCT images of AME and OKC to be distinguished accurately, facilitating the preoperative differential diagnosis of AME and OKC.

Advances in knowledge

ML and radiomic approaches with high-resolution CBCT images provide new insights into the differential diagnosis of AME and OKC.
Machine learning in cardiac stress test interpretation: a systematic review
Authors: Hadida Barzilai Dor , Cohen-Shelly Michal , Sorin Vera , Zimlichman Eyal , Massalha Eias , Allison Thomas G , Klang Eyal
Published: April 2024

Coronary artery disease (CAD) is a leading health challenge worldwide. Exercise stress testing is a foundational non-invasive diagnostic tool. Nonetheless, its variable accuracy prompts the exploration of more reliable methods. Recent advancements in machine learning (ML), including deep learning and natural language processing, have shown potential in refining the interpretation of stress testing data. Adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we conducted a systematic review of ML applications in stress electrocardiogram (ECG) and stress echocardiography for CAD prognosis. Medical Literature Analysis and Retrieval System Online, Web of Science, and the Cochrane Library were used as databases. We analysed the ML models, outcomes, and performance metrics. Overall, seven relevant studies were identified. Machine-learning applications in stress ECGs resulted in sensitivity and specificity improvements. Some models achieved rates of above 96% in both metrics and reduced false positives by up to 21%. In stress echocardiography, ML models demonstrated an increase in diagnostic precision. Some models achieved specificity and sensitivity rates of up to 92.7 and 84.4%, respectively. Natural language processing applications enabled the categorization of stress echocardiography reports, with accuracy rates nearing 98%. Limitations include a small, retrospective study pool and the exclusion of nuclear stress testing, due to its well-documented status. This review indicates the potential of artificial intelligence applications in refining CAD stress testing assessment. Further development for real-world use is warranted.
Myocardial viability on trial
Authors: Bolognese Leonardo , Reccia Matteo Rocco
Published: April 2024

The concept of myocardial viability is usually referred to areas of the myocardium, which show contractile dysfunction at rest and in which contractility is expected to improve after revascularization. The traditional paradigm states that an improvement in function after revascularization leads to improved health outcomes and that assessment of myocardial viability in patients with ischaemic left ventricular dysfunction (ILVD) is a prerequisite for clinical decisions regarding treatment. A range of retrospective observational studies supported this ‘viability hypothesis’. However, data from prospective trials have diverged from earlier retrospective studies and challenge this hypothesis. Traditional binary viability assessment may oversimplify ILVD’s complexity and the nuances of revascularization benefits. A conceptual shift from the traditional paradigm centred on the assessment of viability as a dichotomous variable to a more comprehensive approach encompassing a thorough understanding of ILVD’s complex pathophysiology and the salutary effect of revascularization in the prevention of myocardial infarction and ventricular arrhythmias is required.
Role of glucagon-like peptide-1 agonists in obesity and heart failure with preserved ejection fraction
Authors: Temporelli Pier Luigi
Published: April 2024

Heart failure with preserved ejection fraction (HFpEF) currently represents the majority of all heart failure cases in the community. Glucagon-like peptide-1 agonists represent a class of medications used to treat type 2 diabetes mellitus and, in some cases, obesity. This class includes semaglutide. In the available data from the Semaglutide Treatment Effect in People with Obesity (STEP) trials that were done, looking at weight loss effects of semaglutide, there was a 30–40% reduction in C-reactive protein levels, and that suggests that there is a significant anti-inflammatory effect. Recently, the STEP-HFpEF trial enrolled 529 non-diabetic patients with HFpEF and obesity who were randomly assigned to once-weekly semaglutide (2.4 mg) or placebo for 52 weeks. A statistically significant improvement in the quality of life score and in weight loss was observed. Statistically significant improvements were also seen in the 6 min walk distance, levels of C-reactive protein, and N-terminal pro–B-type natriuretic peptide levels. Interestingly, the Semaglutide Effects on Cardiovascular Outcomes in People with Overweight or Obesity trial has shown that semaglutide produced a consistent reduction of around 20% vs. placebo across major cardiovascular event endpoints over the ∼3-year follow-up in patients with overweight or obesity and cardiovascular disease but not diabetes.
Taboo in cardiology: renin–angiotensin–aldosterone system antagonists worsening renal failure
Authors: Cice Gennaro , Calo' Leonardo
Published: April 2024

The renin–angiotensin–aldosterone system (RAAS) allows normal kidneys to maintain a stable function in every situation of daily life but also intervenes to help when critical situations occur that reduce the filtrate. A typical example is heart failure with reduced ejection function (HFrEF) which inexorably becomes complicated over time with renal failure in what is now commonly defined as cardiorenal syndrome. Renin–angiotensin–aldosterone system antagonists have long been irreplaceable in the treatment of HFrEF due to their beneficial haemodynamic and prognostic effects. However, their use often leads to an acute reduction in the filtrate which often scares the clinician and sometimes leads them to suspend their use. In reality, no guideline has ever clearly indicated when a decline in renal function in a patient taking RAAS antagonists should be acceptable and not lead us to fear the associated acute kidney injury. Usually the nephrologist, called for advice, recommends reducing or suspending the RAAS antagonists, knowing that this will improve the filtration and reassure everyone. But is this the right solution? Are we certain that this choice leads to a better prognosis? This article will try to give a reasonable answer to one of the most frequent doubts that arise in our daily practice.
Percutaneous repair of tricuspid regurgitation
Authors: Mangieri Antonio , Colombo Antonio
Published: April 2024

Tricuspid regurgitation (TR) is common both in patients with left side valvular heart disease and in patients with permanent atrial fibrillation and is associated with increased mortality, morbidity, and an increased risk of hospitalization. Surgery for isolated tricuspid repair is a viable option but burdened by a high-operative risk and a post-operative course characterized by high morbidity. Recently, percutaneous interventional techniques have emerged as a viable option in selected high-risk patients who may clinically benefit from tricuspid valve repair. The purpose of this article is to provide an overview of the current state of transcatheter restorative treatment of TR by providing an overview of new devices in clinical development.
Prevention of thromboembolism after a fracture: is aspirin enough?
Authors: Spoladore Roberto , Milani Martina , Spreafico Luigi Paolo , Agnelli Giancarlo , Savonitto Stefano
Published: April 2024

Venous thromboembolism (VTE) is a serious complication that can arise during and after hospitalization, particularly following surgery under general anaesthesia. Particularly at risk are major orthopaedic surgical procedures such as elective knee or hip replacement and the treatment of hip fractures. In these patients, current guidelines recommend (low or low-moderate level of evidence) aspirin as a possible alternative to anticoagulant therapy for the prophylaxis of long-term venous thromboembolism after an initial period with anticoagulant drugs. Several randomized trials and meta-analyses demonstrate no significant differences in the risk of VTE when comparing aspirin with anticoagulants. However, it must be considered that most recommendations are based on elective orthopaedic surgery and that trials after fractures have excluded patients at high thrombotic risk. Consequently, the overall incidence of major clinical events (death and pulmonary embolism) was ∼1% with wide confidence margins in even large non-inferiority studies. The incidence of asymptomatic VTE, especially distal, appears to be higher with aspirin. Patient preference and lower costs could play an important role in the choice in favour of aspirin.
Moderate aortic stenosis in the dysfunctional ventricle: should it be treated?
Authors: Sciatti Edoardo , Calabrese Alice , Duino Vincenzo , D'isa Salvatore , Di Odoardo Luca Antonio Felice , D'elia Emilia , Senni Michele
Published: April 2024

Moderate aortic stenosis is associated with a worse prognosis than milder degrees. Pathophysiologically, this condition in a dysfunctional ventricle could lead to a further mechanism of haemodynamic worsening, so its treatment should lead to clinical advantages for the patient. The low risk of complications associated with percutaneous correction of aortic valve disease (transcatheter aortic valve implantation) should also be considered, which would seem to favour an interventional approach even in the aforementioned condition. However, sparse data and small population studies make this approach still controversial. Three randomized controlled trials are underway to shed definitive light on the topic.
Real-world validation of smartphone-based photoplethysmography for rate and rhythm monitoring in atrial fibrillation
Authors: Gruwez Henri , Ezzat Daniel , Van Puyvelde Tim , Dhont Sebastiaan , Meekers Evelyne , Bruckers Liesbeth , Wouters Femke , Kellens Michiel , Van Herendael Hugo , Rivero-Ayerza Maximo , Nuyens Dieter , Haemers Peter , Pison Laurent
Published: April 2024

Aims

Photoplethysmography- (PPG) based smartphone applications facilitate heart rate and rhythm monitoring in patients with paroxysmal and persistent atrial fibrillation (AF). Despite an endorsement from the European Heart Rhythm Association, validation studies in this setting are lacking. Therefore, we evaluated the accuracy of PPG-derived heart rate and rhythm classification in subjects with an established diagnosis of AF in unsupervised real-world conditions.

Methods and results

Fifty consecutive patients were enrolled, 4 weeks before undergoing AF ablation. Patients used a handheld single-lead electrocardiography (ECG) device and a fingertip PPG smartphone application to record 3907 heart rhythm measurements twice daily during 8 weeks. The ECG was performed immediately before and after each PPG recording and was given a diagnosis by the majority of three blinded cardiologists. A consistent ECG diagnosis was exhibited along with PPG data of sufficient quality in 3407 measurements. A single measurement exhibited good quality more often with ECG (93.2%) compared to PPG (89.5%; P < 0.001). However, PPG signal quality improved to 96.6% with repeated measurements. Photoplethysmography-based detection of AF demonstrated excellent sensitivity [98.3%; confidence interval (CI): 96.7–99.9%], specificity (99.9%; CI: 99.8–100.0%), positive predictive value (99.6%; CI: 99.1–100.0%), and negative predictive value (99.6%; CI: 99.0–100.0%). Photoplethysmography underestimated the heart rate in AF with 6.6 b.p.m. (95% CI: 5.8 b.p.m. to 7.4 b.p.m.). Bland–Altman analysis revealed increased underestimation in high heart rates. The root mean square error was 11.8 b.p.m.

Conclusion

Smartphone applications using PPG can be used to monitor patients with AF in unsupervised real-world conditions. The accuracy of AF detection algorithms in this setting is excellent, but PPG-derived heart rate may tend to underestimate higher heart rates.
Safety and efficacy of the second-generation cryoballoon for left atrial appendage electrical isolation in canines
Authors: Liu Chao , Li Changjin , Zhao Teng , Yu Manli , Huang Xinmiao , Cao Jiang , Huang Songqun , Guo Zhifu
Published: April 2024

Aims

Left atrial appendage electrical isolation (LAAEI) has demonstrated a significant enhancement in the success rate of atrial fibrillation (AF) ablation. Nevertheless, concerns persist about the safety of LAAEI, particularly regarding alterations in left atrial appendage (LAA) flow velocity and the potential risks of thrombus. This study aimed to assess the efficacy and safety of LAAEI, investigating changes in LAA flow velocity in canines.

Methods and results

The study comprised a total of 10 canines. The LAAEI procedure used by a 23 mm cryoballoon of the second generation was conducted at least 180 s. Intracardiac ultrasonography (ICE) was employed to quantify the velocity flow of the LAA both prior to and following LAAEI. Following a 3-month period, subsequent evaluations were performed to assess the LAA velocity flow and the potential reconnection. Histopathological examination was conducted. Left atrial appendage electrical isolation was effectively accomplished in all canines, resulting in a 100% acute success rate (10/10). The flow velocity in the LAA showed a notable reduction during LAAEI as compared with the values before the ablation procedure (53.12 ± 5.89 vs. 42.01 ± 9.22 cm/s, P = 0.007). After the follow-up, reconnection was observed in four canines, leading to a success rate of LAAEI of 60% (6/10). The flow velocity in the LAA was consistently lower (53.12 ± 5.89 vs. 44.33 ± 10.49 cm/s, P = 0.006), and no blood clot development was observed. The histopathological study indicated that there was consistent and complete injury to the LAA, affecting all layers of its wall. The injured tissue was subsequently replaced by fibrous tissue.

Conclusion

The feasibility of using cryoballoon ablation for LAAEI was confirmed in canines, leading to a significant reduction of LAA flow velocity after ablation. Some restoration of LAA flow velocity after ablation may be linked to the passive movement of the LAA and potential reconnecting. However, this conclusion is limited to animal study; more clinical data are needed to further illustrate the safety and accessibility of LAAEI in humans.