bluuebunny/crossref_metadata_2025 huggingface dataset:
Anisotropic etching behavior and topography formation mechanism of silicon solar cell surface textured by atmospheric plasma
Authors: Zhang Peng , Tian Hengxi , Liu Jinwei , Zhao Yingxin , Cao Xiuquan , Yu Deping
Published: February 2024

Atmospheric plasma etching (APE) has been used to texture Si surfaces due to anisotropic material removal capability. Controlling features and size of the light-trapping structure are keys to improving the reflection performance of silicon (Si) solar cells, which need to fully understand the interfacial etching behavior and the microscopic topography formation mechanism of the Si surface. In this study, microwave plasma with a temperature below 100 °C is employed to investigate the dependence of microstructure evolution on the O/F atom ratios in plasma. The results show that as the O/F atom ratios increase, the microstructure of the Si surface changes from square opening pits to spherical opening pits. High-resolution transmission electron microscopy and x-ray photoelectron spectroscopy analyses indicate that the exciting F atoms dominate the orientation-selective etching process, causing the formation of square opening pits. The CFx and C2 radicals induce the generation of the Si interface reactive layer, resulting in the occurrence of amorphous layers and termination of the non ⟨111⟩-crystal face in APE. The exciting O atoms preferentially occupy the active site of Si surfaces, causing the isotropic etching and then the formation of spherical opening pits. In addition, the richer O atoms will weaken the anisotropic etching ability of F atoms, resulting in the etched surface trends’ flattening. The insight into anisotropic etching behavior and topography formation mechanism of the silicon surface textured by atmospheric plasma is valuable for developing a new texturing approach to silicon solar cells.
Modeling and numerical studies of high-precision laser powder bed fusion
Authors: Wei Yi , Chen Genyu , Tao Nengru , Zhou Wei
Published: February 2024

In order to comprehensively reveal the evolutionary dynamics of the molten pool and the state of motion of the fluid during the high-precision laser powder bed fusion (HP-LPBF) process, this study aims to deeply investigate the specific manifestations of the multiphase flow, solidification phenomena, and heat transfer during the process by means of numerical simulation methods. Numerical simulation models of SS316L single-layer HP-LPBF formation with single and double tracks were constructed using the discrete element method and the computational fluid dynamics method. The effects of various factors such as Marangoni convection, surface tension, vapor recoil, gravity, thermal convection, thermal radiation, and evaporative heat dissipation on the heat and mass transfer in the molten pool have been paid attention to during the model construction process. The results show that the molten pool exhibits a “comet” shape, in which the temperature gradient at the front end of the pool is significantly larger than that at the tail end, with the highest temperature gradient up to 1.69 × 108 K/s. It is also found that the depth of the second track is larger than that of the first one, and the process parameter window has been determined preliminarily. In addition, the application of HP-LPBF technology helps to reduce the surface roughness and minimize the forming size.
Realizing the multifunctional microfluidic flow manipulation based on hydrodynamic metamaterials
Authors: Pang Haixiang , You Yunxiang
Published: February 2024

From their initial application to the fields of chemistry and biology, microfluidic chips used as micro total analysis systems have developed into new technologies to satisfy the requirements of various societal industries. Microchannels are essential components of microfluidic chips; they play a vital role in connecting the inlet and outlet as well as determining the flow distribution and reagent mixing. Microfluidic research has always been devoted to minimizing energy dissipation, fluid resistance, and pressure drop to realize energy-efficient microfluidic chips. This study proposes a new theory for manipulating the flow in microchannels based on hydrodynamic metamaterials according to the spatial transformation theory. In particular, hydrodynamic metamaterials are specifically designed to construct flow shifters, flow splitters, and flow combiners, and theoretical and numerical simulations are performed to assess their hydrodynamic performance. The systematic design of hydrodynamic metamaterial devices proposed in this work establishes a theoretical framework to achieve a steady flow state without inducing unstable flow disturbances in complex-shape microchannels.
Robust mortality prediction on a recirculating aquaculture system
Authors: Costa Vasco , Rocha Eugénio , Marques Carlos
Published: February 2024

Aquaculture presents itself as one of the most rapidly developing means of sustainable production of animal protein to feed ever-growing populations. Recirculating aquaculture systems offer higher control and fewer inconveniences than traditional systems, making them an attractive option for fish production. Although the sector’s digitalization is in its early stages, its application should increase its rentability while conserving the environment. This paper aims to promote the sector’s evolution by assessing parameter importance in mortality with tree-based machine learning models, verifying the method’s natural robustness and how it compares to a specially devised one, and at the same time evaluating the concept’s relevance in predicting categorical mortality values. In particular, to better understand the aquaculture production process through a systematic data evaluation, an exploration based on real-time data acquisition is fully needed. Moreover, algorithm robustness is a key ingredient in this application since measurements are greatly affected by errors. This invalidates the application of traditional machine learning methods, where models are sensitive to production data variations and sensor noise. The study found the parameters that play relevant roles in the production phases, such as pH and nitrate concentration. While the obtained predictive metrics are still sub-optimal, further enhancements could be achieved through rigorous analysis of feature engineering, fine-tuning model hyperparameters, and exploring more advanced algorithms. Additionally, incorporating larger and more diverse datasets, refining data pre-processing techniques, and iteratively optimizing the model architecture may contribute to significant improvements in predictive performance. Despite that, the impact costs of using adjusted machine learning metrics are clear, as are the importance of data rounding in pre-processing and directions for improvement regarding data acquisition and transformation.
Magnetic field-induced narrow first-order and metamagnetic phase transitions of Nd5Ge3
Authors: Samatham S. Shanmukharao , Yenugonda Venkateswara , Babbadi Gowrinaidu , Patwari Muralikrishna , Pathak Arjun K. , Manuel P. , Khalyavin D. , Cottrell Stephen , Hillier A. D. , Suresh K. G.
Published: February 2024

We report on the magnetic behaviour of Nd5Ge3 by investigating through magnetization, neutron diffraction and muon spin relaxation measurements. Temperature dependent-magnetization, muon depolarization rate (λ), initial asymmetry (A0) and the stretched exponent (β) show a clear anomaly at the Néel temperature TN ∼ 54 K. However, the short-range correlated ferromagnetic interactions below TN are inferred from the diffuse scattering mechanism as revealed by zero-field neutron diffraction data. Narrow first order phase transition is due to the competing interaction of a high temperature weak-antiferromagnetic and low temperature glassy states. Magnetic field-induced reentrant spin glass state from a magnetic glass state is observed, before it transforms to a ferromagnetic state.
Structural and magnetic properties of hexagonal ferrite composites with planar and perpendicular anisotropy
Authors: Singh Sonal , Sharma Puneet , Chudasama Bhupendra
Published: February 2024

In the present work, composites of (x)SrFe12O19(SrM)/(1-x) Ba2Co2Fe12O22(Co2Y) [where x = 0.1, 0.2, 0.3, 0.4] were prepared by physical mixing method. The effect of exchange coupling between SrM and Co2Y phases on composites structural, morphological, and magnetic properties has been investigated. XRD patterns confirmed the co-existence of SrM and Co2Y phases with the presence of a secondary Co2Z phase. Smooth hysteresis loops without kink confirmed that SrM and Co2Y phases in composites are exchange-coupled and signify cooperative magnetic switching among M and Y phase spins. A linear increase in magnetization was observed with an increase in M-phase. On the other hand, a decrease in coercivity was observed due to strong intervening coupling between the phases. A single peak in the switching field distribution curve (SFD) of composites also confirm strong coupling between M and Y phases.
Maximizing the output power of magnetically geared generator in low-speed applications using subdomain modeling and particle swarm optimization
Authors: Nguyen Manh-Dung , Kim Su-Min , Shin Hyo-Seob , Shin Kyung-Hun , Phung Anh-Tuan , Choi Jang-Young
Published: February 2024

This study presents an approach to optimizing the output power in a magnetically geared generator by employing subdomain modeling and particle swarm optimization. Accordingly, the subdomain analytical method is utilized to obtain the induced voltage, inductance which are used to predict output power. Afterward, the swarm intelligence optimization technique is applied to reach the maximum output power point. The 12/17/15 prototype evaluated the proposed model by comparing the calculated results and finite element method simulation.
Design considerations for magnetic field generators for future switching applications
Authors: Bouda N. Robert , Gaunkar N. Prabhu , Theh W. Shen , Mina M.
Published: February 2024

Widespread adoption of Magnetic Field Generators (MFG) will require most electro-optical systems to incorporate high current devices, thereby demanding decreased power consumption due to loss reduction. Recent progress in magnetic field generator typologies has shown ways of reducing form factor while meeting better performance in terms of max current and magnetic field level based on selected transistor technologies. However, developments in the standardization of MFGs need to be considered for optoelectronic industrial-scale applications. This work describes a strategy for identifying the optimum condition for a high magnetic field, form factors contributing to power consumption, and the feasibility of such magneto optical.
Optimization method of a magnetic field generating a magnetic force field for magnetic nanoparticle control
Authors: Fushimi M. , Yoshioka H. , Sekino M.
Published: February 2024

We present a novel method for estimating the magnetic field that can generate the desired magnetic force to move magnetic nanoparticles in a region of interest. The magnetic field is expanded using vector spherical harmonics, and the optimal multipole moments are estimated. The multipole moments are included in quadratic form because the magnetic force is defined as the product of the magnetic field and its gradient. We transform the system of quadratic equations into a rank-one-matrix estimation problem to construct a convex numerical algorithm based on a well-established proximal operation. The proposed method was validated using numerical simulations and can be used to design magnetic force patterns that cannot be generated using a simple coil pair.
Anomalies in the magnetostrictive modulation of love surface acoustic waves
Authors: Aguilera J. D. , Loriente R. , Soria L. , Begue A. , Ranchal R. , Gràcia I. , Vallejos S. , Hernando A. , Marín P. , Presa P. de la , Matatagui D.
Published: February 2024

A magnetic surface acoustic wave (SAW) sensor is built by growing a 100 nm galfenol (Fe72Ga28) film by sputtering between the interdigitated transducers of a SAW delay line. Love waves are produced when the shear waves excited on the piezoelectric substrate are guided by a 3.1 μm layer of amorphous SiO2. Due to the magnetostrictive nature of galfenol deposited on top, the application of magnetic fields modulates the propagation of the mechanical excitations along the sensor by the strain coupling. By introducing the delay line in a feedback loop circuit, these changes are studied as resonant frequency variations. Magnetic field cycles of ±40 mT are applied to the sample and the resonant frequency shift is tracked simultaneously. The sensor exhibited hysteretic frequency behavior that depends on the orientation of the applied magnetic field relative to the direction of Love wave propagation. In the configuration in which the wave vector and the applied field form an angle of 45°, the resonant frequency seems to increase with the magnetization induced by the external field. When the wave vector propagation is parallel to the field, two positive peaks appear close to the coercive field of the film, which has not been reported before. This is probably due to a more complex relationship between the acoustic wave and the magnetic state of the film which could be exploited to give rise to new models of magnetic sensors.
Fe-based amorphous powder cores with low core loss and improvement of permeability
Authors: Nguyen Mai Phuong , Yoshida Shigeyoshi , Okamoto Satoshi , Miyazaki Takamichi , Endo Yasushi
Published: February 2024

Fe-based amorphous powder cores of Fe–Si–B–Cr–C magnetic powder and phenolic binder were fabricated, and the effects of annealing and compaction pressure on the soft magnetic properties and core loss were investigated. The formation of Fe–B and α-Fe (Si) phases was confirmed at the annealing temperature above 773 K. The density gradually increased from 5.3 to 5.5 g/cm3 as annealing temperature increased, resulting in the saturation magnetization 4πMs increased to 1.0 T at 773 K. The effect of compaction pressure was studied by using samples annealed at 723 K. Both the density and 4πMs enhanced with compaction pressure from 980 to 1960 MPa. The real part of permeability µ’ remained constant for the frequency up to 2 MHz. The initial value of µ’ increased from 25 to 38 with compaction pressure. Consequently, at Bm of 50 mT and frequency of 100 kHz, the considerably low core loss of 67 kW/m3 was obtained. The low core loss and moderately high permeability of Fe–Si–B–Cr–C amorphous powder core across a wide frequency range indicate its potential for application in high frequency electronic components.
Ultrafast spin–orbit torque-induced magnetization switching in a 75°-canted magnetic tunnel junction
Authors: Nguyen T. V. A. , Naganuma H. , Honjo H. , Ikeda S. , Endoh T.
Published: February 2024

We investigate the switching dynamics of a 75°-canted Spin–orbit torque (SOT) device with an in-plane easy axis using the micro-magnetic simulation. The switching time (τ) is evaluated from the time evolution of the magnetization. The device with a strong out-of-plane magnetic anisotropy (μ0Hkeff = −0.08 T) shows τ = 0.19 ns while a device with a strong in-plane magnetic anisotropy (μ0Hkeff = −0.9 T) shows τ = 0.32 ns. The increase of the damping constant (α) results in the increase of τ for both devices and the sub-nanosecond switching could be retained as α < 0.14 in the device with μ0Hkeff = −0.08 T, while this was achieved as α < 0.04 in the device with μ0Hkeff = −0.9 T. Furthermore when the field-like coefficient (β) is increased, it leads to a decrease in τ, which can be reduced to 0.03 ns by increasing β to 1 in the device with μ0Hkeff = −0.08 T. In order to achieve the same result in the device with μ0Hkeff = −0.9 T, β must be increased to 6. These results indicate a way to achieve ultrafast field-free SOT switching of a few tens of picoseconds in nanometer-sized magnetic tunnel junction (MTJ) devices.
Characteristics of blood flow velocity in the radial artery and finger capillaries using magnetoplethysmogram and photoplethysmogram
Authors: Lee Sang-Suk , Choi Rak-Gun , Kim Won-Tae , Shin Myung-Woo , Choi Jong-Gu , Hasan Mahbub , Jung Byungjo
Published: February 2024

The Hall element and optical sensor, which can detect the magnetic field change caused by the minute fluctuations of the permanent magnet according to the periodic movement of the radial artery and the light absorption and reflection intensity according to the change in wrist blood flow, respectively, are used as key elements in digital healthcare devices. The pulse waves of the radial artery inside the wrist were measured and analyzed using a clip-type pulsimeter, magnetoplethysmogram (MPG). The pulse wave, which is the change in blood flow obtained by photoplethysmogram (PPG), was measured on the dorsal side of the wrist or the fingers simultaneously with MPG. The ABFV (artery blood flow velocity) is a few ten cm/s as DH (distance between MPG and PPG) divided by ΔT(a) which is the time difference between the first peaks of MPG and PPG waveforms on the dorsal side of the wrist. The PBFV (peripheral blood flow velocity) is a few mm/s as LH (hand length) divided by ΔT(p), which is the time difference between the first peak of MPG waveform and the third peak PPG waveform on the finger. For four subjects of 20s, SPWV was approximately 0.98∼1.19 m/s, ABFV in the radial artery was approximately 0.40∼0.44 m/s, and finger capillary PBFV was approximately 6.3∼8.6 cm/s. These results show reasonable values similar to the blood velocity of many blood vessels flowing through the human body.
L10 FePd-based perpendicular magnetic tunnel junctions with 65% tunnel magnetoresistance and ultralow switching current density
Authors: Lyu Deyuan , Shoup Jenae E. , Habiboglu Ali T. , Jia Qi , Khanal Pravin , Zink Brandon R. , Lv Yang , Zhou Bowei , Gopman Daniel B. , Wang Weigang , Wang Jian-Ping
Published: February 2024

L10 FePd is increasingly recognized as a potential candidate for magnetic tunnel junctions (MTJs), yet there remains room for enhancing device performance. In this work, we fabricated fully-integrated L10 FePd-based perpendicular MTJ devices and achieved a significant increase in tunnel magnetoresistance, reaching ∼65%, compared to the previous record of 25%. Notably, we observed bi-directional switching with a low switching current density of about 1.4 × 105 A/cm2, which outperforms the typical spin-transfer torque (STT) MTJ by about one order of magnitude. We propose two possible mechanisms to elucidate the switching process and associated device performance: (1) The voltage-controlled exchange coupling-driven switching of the bottom CoFeB layer; (2) The STT-driven switching of the exchange-coupled L10 FePd–CoFeB composite. While additional research is necessary, these findings may further advance the integration of L10 FePd into spintronic devices, potentially enabling low-energy memory and logic technologies.
Wet chemistry-synthesized Fe/mixed ferrite soft magnetic composites for high-frequency power conversion
Authors: Burgess Ward , Devkota Jagannath , Howard Bret
Published: February 2024

State-of-the-art soft magnetic (SM) alloy systems such as electrical steels and permalloys exhibit large eddy current losses at high-frequency (kHz range and above), limiting their application in fast switching devices. Eddy current losses can be reduced for metallic alloys through a decrease in characteristic length scale or embedding them in an insulation layer. This work proposes the development of fine-scale core materials consisting of metallic SM nano/microparticles with magnetic, inorganic insulation layers, and their synthesis using a wet chemistry-based, scalable method for high frequency and high-power applications. More specifically, a magnetic ferrite coating (Ni0.5-xMnxZn0.5Fe2O4, x = 0.0–0.5) was applied via deposition of ferrite powder produced using a “wet chemistry-based” co-precipitation method; the ferrite was distributed through the Fe micropowder via either ball milling or ultrasonic mixing. Powder cores were prepared by compaction of the synthesized composites. Relative magnetic permeability and core loss were measured at excitation frequencies to 200 kHz. A core loss of 127 kW/m3 was measured at excitation frequency of 100 kHz and magnetization of 0.02 T. This value improves on the 199.3 kW/m3 reported in literature at identical excitation conditions for a compact formed from a composite comprising Fe microparticles coated with low-permeability Ni0.5Zn0.5Fe2O4. Ultrasonic mixing resulted in slightly lower core loss than ball milling, possibly because ball milling causes loss-increasing deformation of the Fe micropowder. XRD and SEM were used to observe composite composition and core cross-section microstructure.
Estimation of the Born data in inverse scattering of layered media
Authors: Jia Zekui , Li Maokun , Yang Fan , Xu Shenheng
Published: February 2024

The first term in the Born series, as we call the Born data, is linear with the scatterers. Here we present a scheme to map the total field data to the Born data in layered media using only the single-input single-output (SISO) setup. This nonlinear mapping is based on the reduced order model (ROM) approach, which constructs ROMs of the original wave operator. Normally, the construction of ROMs requires multi-input multi-output data. By introducing fictitious sensors, we estimate the Born data with SISO data in layered media. We give a simple way of using the time-domain Green’s function to estimate the received data for other fictitious sensors without calculating the complicated Sommerfeld integral. The resulting Born data contains only the single-scattering component, which can be helpful for many imaging applications. A numerical example is given incorporating the direct imaging back-propagation method. It validates the linearity of the Born data by providing an artifact-free image without the optimization process.
On the optimal planform of a cantilever unimorph piezoelectric vibrating energy harvester
Authors: Salman Eliya , Lustig Sahar , Elata David
Published: February 2024

This work relates to piezoelectric vibrating energy harvesters, that are constructed from a unimorph cantilever with a massive edge block. The dynamic response of the cantilever is considered when it is excited into vibrations at its natural frequency, where its deformation amplitude is maximal. The optimal response of such a harvester is achieved when the amplitude of the axial strain in the piezoelectric layer, is uniform. Practical technological considerations dictate the thickness of the unimorph, but its planform geometry (i.e. the vareation of the width along the cantilever) is a design choice. The optimal planform of such a unimorph cantilever has been the focus of many previous studies, which included extensive simulations and experimental investigations. In these previous studies it was concluded that the optimal planform is a trapeze, where the cantilever tapers from its clamped edge towards the edge block. However, to date, no model with explicit predictive capabilities was proposed. In the present study we derive an analytic expression of the planform, that ensures a uniform axial strain over the top surface of a cantilever unimorph with an edge block. Our analysis provides a rational explanation why a trapeze planform is optimal, and provides an explicit functional form of the optimal geometrical parameters of this planform. The predictive capabilities of our model are validated by comparison to finite element simulations.
An analysis of roadside particulate matter pollution and population exposure over the Pearl River Delta region of China under clear-sky condition using new ultra-high-resolution PM2.5 satellite-retrieval algorithms
Authors: Wu Y , Lee H F , Deng R R , Yim S H L
Published: February 2024

Roadside air pollution is one of the serious air pollution problems in urban areas. Even though roadside air pollution has been reported to cause adverse human health impacts, the spatial distribution of roadside air pollution in a large urban agglomeration has yet to be fully assessed. This study aimed to analyse roadside fine particulate matter (PM2.5) pollution and the population exposure in 11 cities in the Pearl River Delta (PRD) region of China. We developed satellite-retrieval algorithms with dark target method, vector support machine model and random forest model to retrieve the spatial distribution of PM2.5 at an ultra-high-spatial-resolution (30 m) based on 30 m Landsat-8 L1 data. Our results show that the retrieved PM2.5 had a promising consistency with PM2.5 measurements at general and roadside stations (R
2 = 0.86; RMSE = 7.72 µg m−3). Moreover, on average, the roadside PM2.5 in Dongguan, Foshan, and Guangzhou was relatively higher (up to 107.60 µg m−3) whereas that in Hong Kong was relatively lower (up to 30.40 µg m−3). The roadside PM2.5 pollution typically occurred in roads for motorized vehicles i.e. motorway, trunk, primary and secondary road. Our results also show that roadside PM2.5 was up to 17% higher in holidays than in workdays in all the PRD cities except Hong Kong that showed roadside PM2.5 higher in workdays than in holidays. The population-weighted PM2.5 decreased with increasing distances from roads in every PRD city, and population-weighted PM2.5 was estimated to be up to 22% higher at roadsides than at distances of 1500 m away from roads. This study pinpointed the seriousness of roadside air pollution in the PRD region.
Globalising innovation through co-inventions–the success case of the Korean lithium-ion battery industry
Authors: Peiseler Leopold , Jun Ye Lin , Schmid Nicolas , Waidelich Paul , Malhotra Abhishek , Schmidt Tobias S
Published: February 2024

Radical innovations can shift the global competitiveness of entire nations. While countries typically struggle to absorb knowledge about novel technologies quickly, in which knowledge tends to be spatially sticky, an important exception is the fast catch-up of the Korean Li-ion battery industry from Japan in the early 2000s. In this paper, we conduct an exploratory case study on this surprising success story. Focussing on patent co-inventions between Korea and Japan, we investigate their significance, as well as underlying types of co-inventions and types of transferred knowledge. To this end, we proceed in four steps: (1) a Poisson regression model; (2) social network analyses; (3) patent inventor tracking and (4) patent coding. Our results indicate that Korean–Japanese co-inventions hold significantly greater influence than other cross-country co-inventions, including with patents without cross-country collaboration. We find a pronounced knowledge-transfer intensity during the early 2000s and observe two types of co-inventions: organisation-level and inventor-level. Predominantly, we observe inventor-level co-inventions, i.e. Korean companies hiring experienced Japanese engineers, that proved important to transferring sticky knowledge. Moreover, while most patents target the design of core battery components, the share of manufacturing patents are—contrary to theoretical expectations—highest during the first half of the observation period. We also discuss our findings and draw implications for policy, industrial and academic players, including industry localisation policies, technology-inherent catch-up strategies and directions for future research.
Transfer operators on graphs: spectral clustering and beyond
Authors: Klus Stefan , Trower Maia
Published: February 2024

Graphs and networks play an important role in modeling and analyzing complex interconnected systems such as transportation networks, integrated circuits, power grids, citation graphs, and biological and artificial neural networks. Graph clustering algorithms can be used to detect groups of strongly connected vertices and to derive coarse-grained models. We define transfer operators such as the Koopman operator and the Perron–Frobenius operator on graphs, study their spectral properties, introduce Galerkin projections of these operators, and illustrate how reduced representations can be estimated from data. In particular, we show that spectral clustering of undirected graphs can be interpreted in terms of eigenfunctions of the Koopman operator and propose novel clustering algorithms for directed graphs based on generalized transfer operators. We demonstrate the efficacy of the resulting algorithms on several benchmark problems and provide different interpretations of clusters.
The impact of digital technology in care homes on unplanned secondary care usage and associated costs
Authors: Garner Alex , Lewis Jen , Dixon Simon , Preston Nancy , Caiado Camila C S , Hanratty Barbara , Jones Monica , Knight Jo , Mason Suzanne M
Published: February 2024

Background

A substantial number of Emergency Department (ED) attendances by care home residents are potentially avoidable. Health Call Digital Care Homes is an app-based technology that aims to streamline residents’ care by recording their observations such as vital parameters electronically. Observations are triaged by remote clinical staff. This study assessed the effectiveness of the Health Call technology to reduce unplanned secondary care usage and associated costs.

Methods

A retrospective analysis of health outcomes and economic impact based on an intervention. The study involved 118 care homes across the North East of UK from 2018 to 2021. Routinely collected NHS secondary care data from County Durham and Darlington NHS Foundation Trust was linked with data from the Health Call app. Three outcomes were modelled monthly using Generalised Linear Mixed Models: counts of emergency attendances, emergency admissions and length of stay of emergency admissions. A similar approach was taken for costs. The impact of Health Call was tested on each outcome using the models.

Findings

Data from 8,702 residents were used in the analysis. Results show Health Call reduces the number of emergency attendances by 11% [6–15%], emergency admissions by 25% [20–39%] and length of stay by 11% [3–18%] (with an additional month-by-month decrease of 28% [24–34%]). The cost analysis found a cost reduction of £57 per resident in 2018, increasing to £113 in 2021.

Interpretation

The introduction of a digital technology, such as Health Call, could significantly reduce contacts with and costs resulting from unplanned secondary care usage by care home residents.
Assessing the feasibility of a multimodal liquid biopsy for the diagnosis of HPV-associated oropharyngeal squamous cell carcinoma
Authors: Lewis James S , Naegele Saskia , Efthymiou Vasileios , Mehrad Mitra , Ely Kim A , Waterboer Tim , Lang Kuhs Krystle A , Davis Seth J , Richard Kelsey , Das Dipon , Faden Daniel L
Published: February 2024

Objectives

In this feasibility study, we explored the combined use of circulating tumor human papillomavirus (HPV) DNA (ctHPVDNA) and HPV serology as diagnostic tests for HPV-associated oropharyngeal squamous cell carcinoma (OPSCC).

Methods

Among patients with research-banked serum or plasma at diagnosis, IgG antibodies to oncoproteins from HPV types 16, 18, 31, 33, 35, 45, 52, and 58 were detected with multiplex serology. Positivity for HPV 16 was defined based on detection of combinations of anti-E6, E1, E2, and E7 and for other high-risk types on detection of anti-E6 and anti-E7. Circulating tumor HPV DNA was detected by custom digital droplet polymerase chain reaction (ddPCR) assays for HPV types 16, 18, 33, 35, and 45. p16 immunohistochemistry and high-risk HPV RNA in situ hybridization (ISH) using a cocktail of 18 high-risk HPV types were performed on tissue.

Results

Of 75 patients, 67 (89.3%) were HPV-associated (p16 and HPV RNA ISH positive) and 8 (10.7%) were HPV-independent. All 8 HPV-independent patients were seronegative and negative for ctHPVDNA (100% specificity). Serology was positive in 53 (79.1%) of 67 HPV-associated patients, while ddPCR was positive for ctHPVDNA in 59 (88.6%) of 67 HPV-associated patients. Requiring both tests to be positive resulted in a sensitivity of 50 (74.6%) of 67 while combining assays (either positive) improved sensitivity to 62 (92.6%) of 67.

Conclusions

Compared to HPV RNA ISH, HPV serology and ctHPVDNA are sensitive and highly specific biomarkers for HPV-associated OPSCC at the time of presentation.
Quantitative transcriptomic and epigenomic data analysis: a primer
Authors: Coussement Louis , Van Criekinge Wim , De Meyer Tim
Published: February 2024

Summary: The advent of microarray and second generation sequencing technology has revolutionized the field of molecular biology, allowing researchers to quantitatively assess transcriptomic and epigenomic features in a comprehensive and cost-efficient manner. Moreover, technical advancements have pushed the resolution of these sequencing techniques to the single cell level. As a result, the bottleneck of molecular biology research has shifted from the bench to the subsequent omics data analysis. Even though most methodologies share the same general strategy, state-of-the-art literature typically focuses on data type specific approaches and already assumes expert knowledge. Here, however, we aim at providing conceptual insight in the principles of genome-wide quantitative transcriptomic and epigenomic (including open chromatin assay) data analysis by describing a generic workflow. By starting from a general framework and its assumptions, the need for alternative or additional data-analytical solutions when working with specific data types becomes clear, and are hence introduced. Thus, we aim to enable readers with basic omics expertise to deepen their conceptual and statistical understanding of general strategies and pitfalls in omics data analysis and to facilitate subsequent progression to more specialized literature.
GeneGPT: augmenting large language models with domain tools for improved access to biomedical information
Authors: Jin Qiao , Yang Yifan , Chen Qingyu , Lu Zhiyong
Published: February 2024

Motivation

While large language models (LLMs) have been successfully applied to various tasks, they still face challenges with hallucinations. Augmenting LLMs with domain-specific tools such as database utilities can facilitate easier and more precise access to specialized knowledge. In this article, we present GeneGPT, a novel method for teaching LLMs to use the Web APIs of the National Center for Biotechnology Information (NCBI) for answering genomics questions. Specifically, we prompt Codex to solve the GeneTuring tests with NCBI Web APIs by in-context learning and an augmented decoding algorithm that can detect and execute API calls.

Results

Experimental results show that GeneGPT achieves state-of-the-art performance on eight tasks in the GeneTuring benchmark with an average score of 0.83, largely surpassing retrieval-augmented LLMs such as the new Bing (0.44), biomedical LLMs such as BioMedLM (0.08) and BioGPT (0.04), as well as GPT-3 (0.16) and ChatGPT (0.12). Our further analyses suggest that: First, API demonstrations have good cross-task generalizability and are more useful than documentations for in-context learning; second, GeneGPT can generalize to longer chains of API calls and answer multi-hop questions in GeneHop, a novel dataset introduced in this work; finally, different types of errors are enriched in different tasks, providing valuable insights for future improvements.

Availability and implementation

The GeneGPT code and data are publicly available at https://github.com/ncbi/GeneGPT.
RNA threading with secondary structure and sequence profile
Authors: Du Zongyang , Peng Zhenling , Yang Jianyi
Published: February 2024

Motivation

RNA threading aims to identify remote homologies for template-based modeling of RNA 3D structure. Existing RNA alignment methods primarily rely on secondary structure alignment. They are often time- and memory-consuming, limiting large-scale applications. In addition, the accuracy is far from satisfactory.

Results

Using RNA secondary structure and sequence profile, we developed a novel RNA threading algorithm, named RNAthreader. To enhance the alignment process and minimize memory usage, a novel approach has been introduced to simplify RNA secondary structures into compact diagrams. RNAthreader employs a two-step methodology. Initially, integer programming and dynamic programming are combined to create an initial alignment for the simplified diagram. Subsequently, the final alignment is obtained using dynamic programming, taking into account the initial alignment derived from the previous step. The benchmark test on 80 RNAs illustrates that RNAthreader generates more accurate alignments than other methods, especially for RNAs with pseudoknots. Another benchmark, involving 30 RNAs from the RNA-Puzzles experiments, exhibits that the models constructed using RNAthreader templates have a lower average RMSD than those created by alternative methods. Remarkably, RNAthreader takes less than two hours to complete alignments with ∼5000 RNAs, which is 3–40 times faster than other methods. These compelling results suggest that RNAthreader is a promising algorithm for RNA template detection.

Availability and implementation

https://yanglab.qd.sdu.edu.cn/RNAthreader
Doubly robust estimation under covariate-induced dependent left truncation
Authors: Wang Yuyao , Ying Andrew , Xu Ronghui
Published: February 2024

In prevalent cohort studies with follow-up, the time-to-event outcome is subject to left truncation leading to selection bias. For estimation of the distribution of the time to event, conventional methods adjusting for left truncation tend to rely on the quasi-independence assumption that the truncation time and the event time are independent on the observed region. This assumption is violated when there is dependence between the truncation time and the event time, possibly induced by measured covariates. Inverse probability of truncation weighting can be used in this case, but it is sensitive to misspecification of the truncation model. In this work, we apply semiparametric theory to find the efficient influence curve of the expectation of an arbitrarily transformed survival time in the presence of covariate-induced dependent left truncation. We then use it to construct estimators that are shown to enjoy double-robustness properties. Our work represents the first attempt to construct doubly robust estimators in the presence of left truncation, which does not fall under the established framework of coarsened data where doubly robust approaches were developed. We provide technical conditions for the asymptotic properties that appear to not have been carefully examined in the literature for time-to-event data, and study the estimators via extensive simulation. We apply the estimators to two datasets from practice, with different right-censoring patterns.
Impact of elevated lipoprotein(a) on coronary artery disease phenotype and severity
Authors: Leistner David M , Laguna-Fernandez Andres , Haghikia Arash , Abdelwahed Youssef S , Schatz Anne-Sophie , Erbay Aslihan , Roehle Robert , Fonseca Ana F , Ferber Philippe , Landmesser Ulf
Published: February 2024

Aims

A thorough characterization of the relationship between elevated lipoprotein(a) [Lp(a)] and coronary artery disease (CAD) is lacking. This study aimed to quantitatively assess the association of increasing Lp(a) levels and CAD severity in a real-world population.

Methods and results

This non-interventional, cross-sectional, LipidCardio study included patients aged ≥21 years undergoing angiography (October 2016−March 2018) at a tertiary cardiology centre, who have at least one Lp(a) measurement. The association between Lp(a) and CAD severity was determined by synergy between PCI with taxus and cardiac surgery (SYNTAX)-I and Gensini scores and angiographic characteristics. Overall, 975 patients (mean age: 69.5 years) were included; 70.1% were male, 97.5% had Caucasian ancestry, and 33.2% had a family history of premature atherosclerotic cardiovascular disease. Median baseline Lp(a) level was 19.3 nmol/L. Patients were stratified by baseline Lp(a): 72.9% had < 65 nmol/L, 21.0% had ≥100 nmol/L, 17.2% had ≥125 nmol/L, and 12.9% had ≥150 nmol/L. Compared with the normal (Lp(a) < 65 nmol/L) group, elevated Lp(a) groups (e.g. ≥ 150 nmol/L) had a higher proportion of patients with prior CAD (48.4% vs. 62.7%; P < 0.01), prior coronary revascularization (39.1% vs. 51.6%; P = 0.01), prior coronary artery bypass graft (6.0% vs. 15.1%; P < 0.01), vessel(s) with lesions (68.5% vs. 81.3%; P = 0.03), diffusely narrowed vessels (10.9% vs. 16.5%; P = 0.01) or chronic total occlusion lesions (14.3% vs. 25.2%; P < 0.01), and higher median SYNTAX-I (3.0 vs. 5.5; P = 0.01) and Gensini (10.0 vs. 16.0; P < 0.01) scores.

Conclusion

Elevated Lp(a) was associated with a more severe presentation of CAD. Awareness of Lp(a) levels in patients with CAD may have implications in their clinical management.
State scope of practice restrictions and nurse practitioner practice in nursing homes: 2012–2019
Authors: Ryskina Kira L , Liang Junning , Ritter Ashley Z , Spetz Joanne , Barnes Hilary
Published: February 2024

Increased engagement of nurse practitioners (NPs) has been recommended as a way to address care delivery challenges in settings that struggle to attract physicians, such as primary care and rural areas. Nursing homes also face such physician shortages. We evaluated the role of state scope of practice regulations on NP practice in nursing homes in 2012–2019. Using linear probability models, we estimated the proportion of NP-delivered visits to patients in nursing homes as a function of state scope of practice regulations. Control variables included county demographic, socioeconomic, and health care workforce characteristics; state fixed effects; and year indicators. The proportion of nursing home visits conducted by NPs increased from 24% in 2012 to 42% in 2019. Expanded scope of practice regulation was associated with a greater proportion and total volume of nursing home visits conducted by NPs in counties with at least 1 NP visit. These relationships were concentrated among short-stay patients in urban counties. Removing scope of practice restrictions on NPs may address clinician shortages in nursing homes in urban areas where NPs already practice in nursing homes. However, improving access to advanced clinician care for long-term care residents and for patients in rural locations may require additional interventions and resources.
Young people’s views about the use of celebrities and social media influencers in gambling marketing
Authors: Pitt Hannah , McCarthy Simone , Randle Melanie , Daube Mike , Thomas Samantha L
Published: February 2024

Young people’s exposure to gambling marketing has had a clear impact on their gambling attitudes, risk perceptions and consumption intentions. Celebrities and social media influencers (SMIs) are increasingly used by the gambling industry in a wide range of promotions. While there is evidence that these types of promotions are influential in shaping young people’s attitudes towards other harmful products, there is limited evidence in relation to gambling. Qualitative focus groups (n = 22) with n = 64, 12–17 year olds were conducted in Australia. These investigated young people’s exposure to celebrity and SMI marketing for gambling and the influence they perceived this marketing had on young people’s gambling attitudes. Reflexive thematic analysis was used to construct four themes from the data. First, young people perceived that celebrities and SMIs created additional appeal and recall of gambling advertisements because they were attention grabbing and familiar. Second, young people thought that celebrities and SMIs increased the trust, legitimacy and social acceptance of gambling. Third, the use of celebrities and SMIs lowered the perceptions of risk associated with gambling. Lastly, there were suggestions to reduce the impact of celebrity and SMI gambling promotions on young people, such as bans and restrictions. This study highlights the importance of a comprehensive approach to preventing young people’s exposure to gambling marketing, that not only considers imposing stronger regulations to restrict the way the gambling industry is allowed to promote its products, but also aims to counter the novel ways the gambling industry attempts to appeal to children and young people.
Heat inactivation of aqueous viable norovirus and MS2 bacteriophage
Authors: Shaffer Marlee , Huynh Kimberly , Costantini Verónica , Vinjé Jan , Bibby Kyle
Published: February 2024

Aims

This study aimed to compare the heat inactivation kinetics of viable human norovirus with the surrogate, MS2 bacteriophage as well as assess the decay of the RNA signal.

Methods and results

Human intestinal enteroids were used to analyze the heat inactivation kinetics of viable human norovirus compared to the surrogate MS2 bacteriophage, which was cultured using a plaque assay. Norovirus decay rates were 0.22 min−1, 0.68 min−1, and 1.11 min−1 for 50°C, 60°C, and 70°C, respectively, and MS2 bacteriophage decay rates were 0.0065 min−1, 0.045 min−1, and 0.16 min−1 for 50°C, 60°C, and 70°C, respectively. Norovirus had significantly higher decay rates than MS2 bacteriophage at all tested temperatures (P = .002–.007). No decrease of RNA titers as measured by reverse transcription-PCR for both human norovirus and MS2 bacteriophage over time was observed, indicating molecular methods do not accurately depict viable human norovirus after heat inactivation and treatment efficiency is underestimated.

Conclusions

Overall, our data demonstrate that MS2 bacteriophage is a conservative surrogate to measure heat inactivation and potentially overestimates the infectious risk of norovirus. Furthermore, this study corroborates that measuring viral RNA titers, as evaluated by PCR methods, does not correlate with the persistence of viable norovirus under heat inactivation.
Unintended Consequences of the Global Derivatives Market Reform
Authors: Gandré Pauline , Mariathasan Mike , Merrouche Ouarda , Ongena Steven
Published: February 2024

Following the early implementation of the global over-the-counter (OTC) derivatives market reform in the USA and the associated increase in trading costs, US banks shifted up to 60% of their OTC derivatives activity abroad, particularly toward less regulated jurisdictions. Consistent with a cost saving incentive of regulatory arbitrage, we find that this flight abroad is driven by costlier blocks of the reform and subsequently causes a narrowing of swap spreads. We further show that this regulatory arbitrage causes an increase in financial risk as more activity is shifted to more lenient jurisdictions.