bluuebunny/crossref_metadata_2025 huggingface dataset:
A sensor system integrating sensing and intelligence based on MEMS reservoir computing
Authors: Guo Xiaowei , Yang Wuhao , Zou Xudong
Published: April 2024

Reservoir computing (RC) is a bio-inspired neural network structure which is easy to be implemented in hardware. It has been constructed in a great many fields such as memristor, electrochemical reaction, among which MEMS is the closest to integrate sensing and computing. We propose a novel sensor system of MEMS RC based on stiffness modulation, that natural signal directly affects the system stiffness as the input. Under this paradigm, information can be processed locally without data collection and pre-processing. We inherited the nonlinearity tuning principle and optimized the post-processing algorithm by creating a digital mask operator. In this way, the system can deal with classification tasks as well as forecasting tasks. We integrated MEMS, IC and FPGA with a small volume and low power consumption, so complicated setup for data discretization and transduction in traditional MEMS RC is eliminated. The system can process word classification and chaos forecasting with high accuracy, which preliminarily proves the integrated RC architecture.
Mixed metal differentiation method using microfluidic oil detection sensors
Authors: Xie Yucai , Shi Haotian , Zhang Hongpeng
Published: April 2024

This paper analyzes the characteristics of iron particles and copper particles in the alternating magnetic field with the change of excitation frequency, and proposes a method of using microfluidic oil detection sensor to achieve the distinction of mixed metals. The magnetic field strength of the coil is changed by changing the excitation frequency, which in turn makes the metal particles of different materials act with different strengths in the magnetic field, and realizes the accurate detection of the particles. In the article, firstly, the magnetization effect of the particles in the alternating magnetic field is simulated by the simulation software, the change of the magnetization effect with frequency is simulated, and the change curve of the inductance signal when the particles pass is obtained. Then the experimental verification is carried out by building a test bench, and the experimental results are consistent with the simulation results, which all confirm the feasibility of realizing the detection of aliased particles by frequency conversion. The method provides a new reference direction for the precise and accurate detection of oil detection technology, and has good research value.
Optical force on yeast cells generated from surface plasmon polaritons
Authors: Zhao Hangxin , Song Xinyu , Han Xue
Published: April 2024

The surface plasmon resonance phenomenon is widely used in sensing, near-field control, and nonlinear optics. In this paper, the optical near-field generated by the surface plasmon resonance phenomenon is applied to trap yeast cells. The effect of the relative axial distance between the gold film surface and the waist of the focused beam on the trap stiffness is studied. There is a maximized trap stiffness at a specific relative axial distance for trapping yeast cells. The trap stiffness is significantly higher than the value at other locations. This study can be applied to screening of particles with different sizes.
Low stress packaging of the small three-axis gyro
Authors: Yunjie Yang , Yunkang Song , Xin Yan , Gang Wang , Huaxiang Yi , Zhengnan Zhang , Jiang Rao
Published: April 2024

High-precision combined three-axis MEMS gyroscope is popular because of its high integration and miniaturization, but it also puts forward higher requirements for packaging. In this paper, the designed stress isolation structure is bonded between the MEMS chip and the package substrate according to the low stress method, which said the external stress is blocked and offset by the reverse stress generated by the elastic beam in the stress isolation structure, so as to ensure that the MEMS chip is kept in a low stress state. Simulation results show that the stress isolation structure can block 93.3% of the stress transmitted by the outside world. In the actual test, the stress isolation structure can also ensure that the output of the single-axis module of the three-axis gyro is stable and reliable, so as to improve the survival rate of the product.
FPGA-based interference elimination for health monitoring in dynamic environments
Authors: Jiang Jiaxin , Pan Yijing , Wang Xiang , Li Shufan , Zhang Runyang , Liu Yifang , Zheng Gaofeng , Zhuo Liyun , Li Wenwang
Published: April 2024

Since flexible wearable sensing devices are mostly used to acquire the human health information by fitting, the vibration generated by the wearer’s movement, physiological state, environment, and other dynamic factors will interfere the accuracy of collected signals. In order to solve the signal interference problem in dynamic environments, a system is needed to eliminate the strong interfering signals in disturbing scenarios in order to acquire the target signal. In this paper, a FPGA-based system is designed to eliminate the signal interference, where a PFGA chipset is served as the core hardware part, an adaptive notch filter is used to process the sensing signals and the FPGA and the host computer are interacted in real time, thus various vibration noises suffered by the flexible sensing device could be eliminated when it is applied to health monitoring in dynamic environments.
A frequency meter based on Costas FLL for resonant accelerometers
Authors: Yafei Xie , Rui Feng , Liuhui Zhou , Jiazhan Fu , Yahui Su , Ming Zhou
Published: April 2024

The resonant accelerometer (RA) is an important part for high-performance inertial devices. And high accuracy frequency measurement is one of the key technology for RA. This paper developed a frequency meter based on Costas frequency lock loop (FLL). This structure is flexible as the analog input sinusodial voltage wave is converted into digital domain by an ADC and the frequency measurement function dealing with that voltage could be implemented only with digital circuits. The transfer function of the frequency meter is determined by the loop filter of the FLL and the closed system is always stable for PID controller. The noise in the loop is reshaped by a first order ∑-Δ modulator formed by the frequency meter loop, which relaxes the requirement for the accuracy of ADC. A test board for the frequency meter is implemented with a 24-bit ADC and FPGA, and achieves a noise of

1

mHz
/

Hz

at low frequency band,

7

µ
Hz
/

Hz

around 50 Hz with a 40 kHz sinusodial input voltage.
Heterogeneous Integration for High Performance Electronic and Photonic Devices
Authors: Dai Jiayun , Wang Fei , Li Guanyu , Jia Chenyang , Ling Zhijian , Chen Xin , Kong Yuechan , Chen Tangsheng
Published: April 2024

In this paper, two representative heterogeneous integrated applications with great performance based on epitaxial layer transfer process are reported. The SiC integrated Si PIN limiter has shown power handling capability of 150W (continues Wave) and 370W (long pulse) at 5.4GHz, which shows outstanding performance than conventional GaAs limiter. While the SiC integrated InP PIN photodetector has shown a high performance of 3-dB bandwidth over 67GHz, and 42% increasing of the optical responsibility over 0.51 A/W compared to the traditional PD. The results verified great potential of transistor level heterogeneous integration for high performance electronic and photonic devices.
Fabrication and application of flexible piezoelectric sensor based on electrospun PVDF-TrFE nanofibers
Authors: Li Wenwang , Xie Angda , Jiang Jiaxin , Zheng Gaofeng , Li Shufan , Zhang Runyang , Wang Xiang
Published: April 2024

Flexible piezoelectric sensors have recently demonstrated great promise for use in wearable electronics and electronic skin. In this study, electrospinning was used to generate piezoelectric PVDF-TrFE nanofiber sensors. The relationship between nanofiber alignment orientation and piezoelectric property was examined. The experimental results demonstrated that the piezoelectric property improved with the increasing of nanofiber alignment orientation. The response time of piezoelectric sensor was 2 ms, and the sensitivity was 0.446 V/N and 0.029 V/N at vibration frequency of 5 Hz and 1 Hz, respectively. In addition, the applications of flexible piezoelectric sensor in human joint movements and surface contact have been demonstrated, indicates the potential in the field of motion monitoring.
Design of a PWM/PFM hybrid modulation switching circuit for a four-switch buck-boost converter
Authors: Song N. , Fang S. , Zhao C. , Wang Y.
Published: April 2024

Based on the application background of fuel cell, the conversion efficiency of the four-switch Buck-Boost converter using PWM (Pulse width modulation) is low at light load, and the conversion efficiency of the four-switch Buck-Boost converter using PFM (Pulse frequency modulation) is low at heavy load. A PWM/PFM hybrid modulation circuit using digital module to detect induced current and feedback voltage is presented. The circuit structure is simple and easy to integrate. It has the effect of fast selection according to inductance current and feedback voltage. The circuit works in PWM mode by default. After soft startup, PWM/PFM mode can be switched according to the load. Finally, simulation is carried out in FSBB converter. The experimental results show that the PWM/PFM hybrid modulation circuit has the function of multi-load lead switching mode and protection mechanism. Simulation in FSBB converter shows that the converter efficiency reaches 91.99% and the maximum load current is 2A. This helps improve the efficiency of Buck-Boost converters.
Equipment develop and experiment study of the synchronization of electrospinning and electrospray
Authors: Wang Xiang , Shi Haochen , Pan Zaibin , Jiang Jiaxin , Li Shufan , Zhang Runyang , Liao Wenhai , Zheng Gaofeng , Li Wenwang
Published: April 2024

High-performance multi-functional nanomaterials have broad applications in various industrial fields. The assembling of nanofibers and nanoparticles prepared by electrospinning and electrospray is a typical structure for the functional combination of multi-materials. However, due to different solution properties and processing parameters, as well as the simultaneous mutual interferences, the controlling of the synchronization of electrospinning and electrospray technology is in an urgent demand. In this paper, an equipment was developed to realize the synchronization of electrospinning and electrospray technology, and multi-functional nanomaterials combining nanofibers and nanoparticles was achieved. Then, thermoplastic polyurethanes (TPU)/grapheneoxide (GO) and poly(lactic acid) PLA/polyaniline (PANI) membrane was prepared based on the self-developed equipment, verifying the process of the synchronization of electrospinning and electrospray.
Circuit design of a novel front readout circuit for SiC neutron detector with leakage current compensation
Authors: Liu J. , Liu Y. , Fang S. , Liu X. , Wang Y.
Published: April 2024

Radiation detectors have broad application prospects in environmental radiation monitoring, radiation source identification, biomedical imaging, space exploration, astrophysics, other radiation detection and imaging fields. Among the third generation semiconductors, the properties of 4H-SiC are more suitable for making high-temperature and strong radiation neutron detectors. SiC materials have become a current research hotspot. In this paper a special readout integrated circuit is designed for the extremely weak current pulse signal output by SiC trench neutron detector. A leakage current compensation circuit is designed for the influence of leakage current on charge sensitive amplifier(CSA) output baseline. The noise of CSA output is analyzed and the noise minimization is carried out. The circuit can quickly respond to the input signal and extract the energy and time information. The circuit is designed based on the DB Hitek 0.18μm CMOS process model. The layout design is achieved and the post-simulation is completed. Simulated results show that the equivalent input charge range of the system is about 2fC ∼ 20fC. The charge conversion gain is 88mV/fC. The nonlinear error is within 1.6 %. Moreover, the equivalent noise charge is 22e-. The circuit has the advantages of high gain, high linearity and low noise. Therefore, the circuit can effectively adapt to the characteristics of the charge signal output from SiC trench neutron detectors and amplify the output charge signal.
Finite element simulation and experiment of residual stress evolution in MEMS structures
Authors: Wen Xiao , Chen Jinchuan , Huang Qinwen , Guo Huihui
Published: April 2024

The MEMS device structure is usually formed by the combination of thick film and thin film deposition of many different materials, and the residual stress generated in the process of integration/superposition of different materials has a significant impact on the performance and reliability of the device.In this study, a test structure of a multilayer thin film was designed and processed. Based on this, finite element modeling analysis and reliability experiment, analyze the evolution of residual stress and construct the corresponding theoretical analysis model. The finite element modeling analysis can characterize the evolution and distribution laws of residual stress. The reliability experiment is mainly by carrying out the temperature shock experiment, and measuring the resistance value, resonance frequency and the surface morphology of the device, so as to better reflect the change of residual stress. Through this study, the resonant frequency and surface morphology of the device can reflect the residual stress of the device, which provides help for the test and analysis of the residual stress. To a certain extent, it can help reduce the harm caused by the residual stress in the design and manufacturing process, and improve the performance and reliability of MEMS devices.
A low-noise, radiation-hardened charge-sensitive amplifier for Silicon carbide neutron detector
Authors: Liu X. , Liu Y. , Fang S. , Wang Y.
Published: April 2024

Silicon carbide(SiC) neutron detectors can be applied to extreme environments with high temperature and strong radiation. The total noise factor is most significantly influenced by the noise factor of the first stage in a cascade amplifier. Hence, the preamplifier must exhibit exceptional noise performance. The readout circuit is inevitably exposed to the influence of radiation, which may result in temporary or even permanent failure of electronic systems. The connection method between the SiC neutron detector and the readout circuit is typically DC-coupled. When the sensor is working, the leakage current generated by the sensor will enter the input end of the CSA and change the baseline position of the CSA. In this paper, a low-noise CSA with leakage current compensation circuit(LCC) is presented. The circuit’s voltage-to-charge amplification is 2.98mV/fC, and the error due to nonlinearity is below 0.01%. Without considering the input parasitic capacitance, ENC is 43.12e-. In addition, the circuit also has good radiation resistance and leakage current compensation function. It is implemented and simulated in the DB Hitek 0.18μm CMOS process model.
A silicon resonant pressure sensor based on thermal stresses matched structures
Authors: Yu Hengshu , Wang Junbo , Lu Yulan , Xie Bo , Shang Yanlong , Liu Zhao
Published: April 2024

This paper introduced a silicon resonant pressure sensor based on thermal stress-matched structures to extend the operating temperature range. The sensor designed this time consists of an SOI wafer with a pressure-sensitive diaphragm for pressure sensing and two integrated resonators, a silicon wafer for vacuum packaging, and a glass wafer for additional stress isolation. The multilayer structures were bonded together to form a thermal stress-matched part to address the problem of temperature inflection points of conventional resonant pressure sensors within broad temperature zones. Finite element analyses optimized the sensor’s pressure- and temperature-sensitive characteristics. Micromachining based on eutectic and anodic bonding to fabricate sensor chips. Characterization results indicated the developed pressure sensor can work stably in a wide temperature range of -55∼125°C and has excellent fitting accuracy exceeding ±0.01% FS., which showed a better performance than previously reported counterparts.
Aluminum Nitride Thin Film Pyroelectric Detector Based on Metamaterial Absorber
Authors: Zhang Congchun , Zhao Yongmin , Han Yulu , Ci Guangteng , Yin Lumeng , Zhao Xiaoguang , Ming Anjie , Wei Feng , Mao Changhui
Published: April 2024

Highly integrated pyroelectric detectors have been widely used in infrared spectrometers and gas detection. Aluminum nitride(AlN) has excellent compatibility with CMOS processes and is often used to fabricate piezoelectric and optoelectronic devices with superior performance. This study proposes a pyroelectric detector with AlN thin film as the sensitive element and integrated metamaterial absorber. Magnetron sputtering technology was used to prepare the AlN thin film as the sensitive element. To achieve narrowband specific absorption subsequently, a three-layer metamaterial absorber structure was designed and simulated. Preliminary processing of AlN pyroelectric detectors was performed based on MEMS technology. The designed narrowband absorbing structure exhibits near unity specific absorption, with a quality factor of 17.75. This study preliminarily verifies the application potential of AlN thin films in mid-infrared pyroelectric sensors, and realizes narrowband absorption through metamaterial structures, laying the foundation for the development of mid-infrared gas detection sensors.
Microfluidic enabled flexible sensors based on self-diffusion MWCNTs dispersion
Authors: Li Yuzhen , Qian Xiang
Published: April 2024

Flexible microfluidic pressure sensors have recently attracted a lot of attention due to its revolutionary potential in the field of healthcare. These sensors provide non-invasive, highly sensitive, and adaptable options for tracking various aspects of human movement and health. Nevertheless, there are a number of limitations that affect the effectiveness of microfluidic pressure sensors, including material selection, sensor packaging techniques, sensitivity, and stability. The research outlined in this paper, which aims to address these issues head-on and significantly improve the functionality of microfluidic pressure sensors in order to increase their usefulness in the fields of medical and biomedical applications.
A novel self-powered sensitive porous ZnO NWs/PDMS sponge capacitive pressure sensor
Authors: Liu Xinyue , He Mengfan , Djoulde Aristide , Wang Zhiming , Liu Mei
Published: April 2024

The demand for flexible sensors has increased due to the explosive expansion of flexible electronic applications, but there are concerns that the development of high-precision measurement is limited. Capacitive pressure sensors are extensively utilized among diverse sensors due to their simple structure, high resolution, and outstanding dynamic response characteristics. Therefore, by sandwiching a porous ZnO NWs PDMS (PZP) sponge dielectric layer between two ITO/PET electrodes, a flexible capacitive pressure sensor with high sensitivity, short response time, and wide working range was prepared. The porous PDMS sponge was prepared utilizing the salt particle as a template, then ZnO NWs in different precise proportions were added to it. The sensitivity of PZP sponge capacitive pressure sensors with different salt particle sizes and ZnO NWs dosages were compared. The research results indicate that when salt particle sizes less than 150 μm, and the amount of ZnO NWs in PZP sponge is increased to 200 mg, the sensor sensitivity is highest in the pressure range of 2.5-7.5 kPa, reaching 0.1279 kPa-1, response time less than 70 ms. When the PZP sponge sensor is used as a self-powered source, it achieves the best output of 1.2 V and 6.8 nA at 5.74 kPa pressure. It provides a new way to tackle the challenge of low sensitivity of flexible sensors to capacitive signal and lays a foundation for expanding the application scenarios of ZnO NWs.
Design and Fabrication of Quartz MEMS Based Double-ended Tuning Fork Resonator
Authors: Bi X. , Ma Y. , Wang X. , Hua X. , Liu Y. , Sun S.
Published: April 2024

This paper presents the design and fabrication of double-ended tuning fork (DETF) resonator based on quartz. DETF resonator was designed with two tines structure, due to this configuration has the advantage of providing dynamic balance. Both surface and side electrode were designed on DETF tines in order to enhance the piezoelectric effect. DETF resonator was fabricated from a quartz substrate by chemical wet etching and photolithography processes, the key feature of fabrication is to create Cr/Au metal films, which should be strong enough to withstand the aggressive quartz etchant, meanwhile, the wet etching parameters was optimized in order to reduce the sidewall structure in +X orientation which can greatly deteriorate vibrating characteristics of DETF tines. Experimental results demonstrated that the Q value would be lowered and motional resistance be increased with the force sensitivity increase of DETF tines.
Leaf unfolding and lamina biomechanics in Syngonium podophyllum and Pilea peperomioides
Authors: Modert Michelle , Speck Thomas , Masselter Tom
Published: April 2024

In nature, leaves and their laminae vary in shape, appearance and unfolding behaviour. We investigated peltate leaves of two model species with peltate leaves and highly different morphology (Syngonium podophyllum and Pilea peperomioides) and two distinct unfolding patterns via time-lapse recordings: we observed successive unfolding of leaf halves in S. podophyllum and simultaneous unfolding in P. peperomioides. Furthermore, we gathered relevant morphological and biomechanical data in juvenile (unfolding) and adult (fully unfolded) leaves of both species by measuring the thickness and the tensile modulus of both lamina and veins as a measure of their stiffness. In S. podophyllum, lamina and veins stiffen after unfolding, which may facilitate unfolding in the less stiff juvenile lamina. Secondary venation highly contributes to stiffness in the adult lamina of S. podophyllum, while the lamina itself withstands tensile loads best in direction parallel to secondary veins. In contrast, the leaf of P. peperomioides has a higher lamina thickness and small, non-prominent venation and is equally stiff in every region and direction, although, as is the case in S. podophyllum, thickness and stiffness increase during ontogeny of leaves from juvenile to adult. It could be shown that (changes in) lamina thickness and stiffness can be well correlated with the unfolding processes of both model plants, so that we conclude that functional lamina morphology in juvenile and adult leaf stages and the ontogenetic transition while unfolding is highly dependent on biomechanical characteristics, though other factors are also taken into consideration and discussed.
Catchment-scale thawing and greening decreases long-term nitrogen export in NE Greenland
Authors: Speir Shannon L , Tank Jennifer L , Pastor Ada , Muller Marc F , Mastepanov Mikhail , Riis Tenna
Published: April 2024

Climate change is expected to alter nitrogen (N) export from Arctic rivers, with potential implications for fragile coastal ecosystems and fisheries. Yet, the directionality of change is poorly understood, as increased mobilization of N in a ‘thawing’ Arctic is countered by higher rates of vegetative uptake in a ‘greening’ Arctic, particularly in the understudied region of Greenland. We use an unprecedented dataset of long-term (n = 18 years) river chemistry, streamflow, and catchment-scale changes in snow and vegetation to document changing riverine N loss in Greenland. We documented decreasing inorganic and organic N loads, linked to decreasing snow stores, warming soils, and enhanced plant uptake. Higher variability in N export across years also points to the increasing role of high flow events in driving downstream N loss. This alteration in N cycling may significantly reduce both inorganic and organic N transport across the terrestrial-aquatic boundary during the open water season in a rapidly warming Greenland.
Investigation of tribological behavior of coated and untreated rail steels under wet conditions
Authors: Cetin M Huseyin , Kondul Bilgehan
Published: April 2024

Rails are exposed to more stresses, especially in the regions of narrow radius curves and switch passages. Therefore, the tribological features of these regions are important. In this study, the effect of boronization on tribological properties was examined. For this purpose, experiments were carried out on samples boronized at 800 °C for 2 h and 8 h and on untreated samples. With these experiments, the friction coefficient, volume loss and surface roughness values of the samples under wet conditions were examined. In addition, the microstructures of the material after boriding were observed by SEM and EDX. The variance and regression method (ANOVA) was used for the statistical analysis of the experimental results. After SEM examinations, a coating layer of ∼22 μm (FeB) and ∼48 μm (FeB+Fe2B) were obtained on the surface of the rail steels boronized for 2 and 8 h, respectively. The microhardness of the rail steels, which was ∼300 HV for the untreated sample, increased to ∼1900 HV and ∼2400 HV with the boronizing process boronized for 2 and 8 h, respectively. According to the ANOVA results, the effects of the boronizing process on the decrease of the friction coefficient and the volume loss were calculated as 42% and 46%, respectively. Finally, according to the corrosion results, the corrosion resistance of the boronized rail steels decreased with the boride layer formed.
Information flow in parameterized quantum circuits
Authors: Anand Abhinav , Bjørn Kristensen Lasse , Frohnert Felix , Sim Sukin , Aspuru-Guzik Alán
Published: April 2024

In this work, we introduce a new way to quantify information flow in quantum systems, especially for parameterized quantum circuits (PQCs). We use a graph representation of the circuits and propose a new distance metric using the mutual information between gate nodes. We then present an optimization procedure for variational algorithms using paths based on the distance measure. We explore the features of the algorithm by means of the variational quantum eigensolver, in which we compute the ground state energies of the Heisenberg model. In addition, we employ the method to solve a binary classification problem using variational quantum classification. From numerical simulations, we show that our method can be successfully used for optimizing the PQCs primarily used in near-term algorithms. We further note that information-flow based paths can be used to improve convergence of existing stochastic gradient based methods.
Unique correlation between electrical, structural properties and electromagnetic shielding properties of carbon nanotube sheets
Authors: Choi Minseouk , Cho Young Shik , Park Kyung Tae , Lee Kyunbae , Shin Keun-Young , Jung Yeonsu , Kim Taehoon
Published: April 2024

Correlation between electrical, structural properties and electromagnetic shielding efficiency (EMI SE) of carbon nanotube sheets (CNTSs) was investigated. Solvent densification of CNTSs led to enhancements of carbon nanotube (CNT) bundling behavior and densification in the thickness direction while maintaining the areal density of the CNTSs. These structural modifications resulted in enhanced electrical properties and reduced sheet thickness by modifying the microstructure and bundling characteristics. Remarkably, contrary to conventional EMI shielding materials, the sheet resistance which reflects bundling behavior and microstructure of CNTSs, is the critical factor affecting the EMI SE of the CNTSs rather than electrical conductivity. The findings provide fundamental insights essential for the design of EMI shielding films incorporating CNTs.
Validating a data-driven framework for vehicular traffic modeling
Authors: Lane Daniel , Roy Subhradeep
Published: April 2024

This study presents a data-driven framework for modeling complex systems, with a specific emphasis on traffic modeling. Traditional methods in traffic modeling often rely on assumptions regarding vehicle interactions. Our approach comprises two steps: first, utilizing information- theoretic (IT) tools to identify interaction directions and candidate variables thus eliminating assumptions, and second, employing the sparse identification of nonlinear systems (SINDy) tool to establish functional relationships. We validate the framework’s efficacy using synthetic data from two distinct traffic models, while considering measurement noise. Results show that IT tools can reliably detect directions of interaction as well as instances of no interaction. SINDy proves instrumental in creating precise functional relationships and determining coefficients in tested models. The innovation of our framework lies in its ability to use data-driven approach to model traffic dynamics without relying on assumptions, thus offering applications in various complex systems beyond traffic.
Random feedback alignment algorithms to train neural networks: why do they align?
Authors: Chu Dominique , Bacho Florian
Published: April 2024

Feedback alignment algorithms are an alternative to backpropagation to train neural networks, whereby some of the partial derivatives that are required to compute the gradient are replaced by random terms. This essentially transforms the update rule into a random walk in weight space. Surprisingly, learning still works with those algorithms, including training of deep neural networks. The performance of FA is generally attributed to an alignment of the update of the random walker with the true gradient—the eponymous gradient alignment—which drives an approximate gradient descent. The mechanism that leads to this alignment remains unclear, however. In this paper, we use mathematical reasoning and simulations to investigate gradient alignment. We observe that the feedback alignment update rule has fixed points, which correspond to extrema of the loss function. We show that gradient alignment is a stability criterion for those fixed points. It is only a necessary criterion for algorithm performance. Experimentally, we demonstrate that high levels of gradient alignment can lead to poor algorithm performance and that the alignment is not always driving the gradient descent.
Effects of medication management in geriatric patients who have fallen: results of the EMMA mixed-methods study
Authors: Clemens Stephanie , Iglseder Bernhard , Alzner Reinhard , Kogler Magdalena , Rose Olaf , Kutschar Patrick , Krutter Simon , Kanduth Karin , Dückelmann Christina , Flamm Maria , Pachmayr Johanna
Published: April 2024

Background

comprehensive medication management (CMM) can reduce medication-related risks of falling. However, knowledge about inter-individual treatment effects and patient-related barriers remains scarce.

Objective

to gain in-depth insights into how geriatric patients who have fallen view their medication-related risks of falling and to identify effects and barriers of a CMM in preventing falls.

Design

complementary mixed-methods pre–post study, based on an embedded quasi-experimental model.

Setting

geriatric fracture centre.

Methods

qualitative, semi-structured interviews framed the CMM intervention, including a follow-up period of 12 weeks. Interviews explored themes of falling, medication-related risks, post-discharge acceptability and sustainability of interventions using qualitative content analysis. Optimisation of pharmacotherapy was assessed via changes in the weighted and summated Medication Appropriateness Index (MAI) score, number of fall-risk-increasing drugs (FRID) and potentially inappropriate medications (PIM) according to the Fit fOR The Aged and PRISCUS lists using parametric testing.

Results

thirty community-dwelling patients aged ≥65 years, taking ≥5 drugs and admitted after an injurious fall were recruited. The MAI was significantly reduced, but number of FRID and PIM remained largely unchanged. Many patients were open to medication reduction/discontinuation, but expressed fear when it came to their personal medication. Psychosocial issues and pain increased the number of indications. Safe alternatives for FRID were frequently not available. Psychosocial burden of living alone, fear, lack of supportive care and insomnia increased after discharge.

Conclusion

as patients’ individual attitudes towards trauma and medication were not predictable, an individual and longitudinal CMM is required. A standardised approach is not helpful in this population.
Barriers and facilitators to early mobilisation and weight-bearing as tolerated after hip fracture surgery among older adults in Saudi Arabia: a qualitative study
Authors: Turabi Ruqayyah Y , Sheehan Katie J , Guerra Stefanny , O'Connell Matthew D L , Wyatt David
Published: April 2024

Objective

To explore the practice of prescribing and implementing early mobilisation and weight-bearing as tolerated after hip fracture surgery in older adults and identify barriers and facilitators to their implementation.

Methods

Semi-structured interviews were conducted with 20 healthcare providers (10 orthopaedic surgeons and 10 physiotherapists) from Saudi Arabian government hospitals. Data were analysed using inductive thematic analysis.

Results

While early mobilisation and weight-bearing as tolerated were viewed as important by most participants, they highlighted barriers to the implementation of these practices. Most participants advocated for mobility within 48 h of surgery, aligning with international guidance; however, the implementation of weight-bearing as tolerated was varied. Some participants stressed the type of surgery undertaken as a key factor in weight-bearing prescription. For others, local protocols or clinician preference was seen as most important, the latter partially influenced by where they were trained. Interdisciplinary collaboration between orthopaedic surgeons and physiotherapists was seen as a crucial part of postoperative care and weight-bearing. Patient and family member buy-in was also noted as a key factor, as fear of further injury can impact a patient’s adherence to weight-bearing prescriptions. Participants noted a lack of standardised postoperative protocols and the need for routine patient audits to better understand current practices and outcomes.

Conclusion

This study contributes to national and global discussions on the prescription of early mobilisation and weight-bearing as tolerated. It highlights the necessity for a harmonised approach, incorporating standardised, evidence-based protocols with patient-specific care, robust healthcare governance and routine audits and monitoring for quality assurance and better patient outcomes.
A report on the safety of acitretin use in patients with renal failure on haemodialysis
Authors: Shim Paul Jaehoon , Quintos Jessica Leigh , Faraz Khushnood , Smith Isabelle Taylor , Petty Amy Jiayue , Bottomley Matthew , Wheless Lee Emerson , Whitley Melodi Javid
Published: April 2024

Acitretin, commonly used for severe psoriasis and keratinocyte carcinoma chemoprevention in high-risk patients, is contraindicated in patients with end-stage renal disease (ESRD) on haemodialysis (HD). However, these patients often lack medication choices and in certain clinical scenarios the benefits of acitretin may outweigh the potential risks. We identified 24 patients with ESRD on HD undergoing acitretin treatment from the Duke and Vanderbilt University Medical Centers. While adverse effects were common, they were not a frequent cause of treatment discontinuation among patients. We also found no association between acitretin treatment and hospital admissions or mortality. Lastly, we found statistically significant increases in alkaline phosphatase (ALP; P = 0.03) and total bilirubin (P < 0.001) when patients were receiving acitretin and HD compared with baseline. However, there was no dose dependency or temporal association with acitretin or HD initiation. Based on these preliminary findings, we find that acitretin may safely be used in patients receiving HD, with close monitoring of ALP and bilirubin.
ERAP1 and ERAP2 gene variants as potential clinical biomarkers of anti-interleukin-17A response in psoriasis vulgaris
Authors: Kronborg Lasse , Hansen Emma Oxlund , Bertelsen Trine , Rittig Anne Hald , Emmanuel Thomas , Jørgensen Sofie , Hjuler Kasper Fjellhaugen , Iversen Lars , Johansen Claus
Published: April 2024

Background

Interleukin (IL)-17A is a proinflammatory cytokine that plays an essential role in the development of psoriasis. Although treatment with anti-IL-17A monoclonal antibodies has demonstrated high efficacy in patients with psoriasis, not all patients respond equally well, highlighting the need for biomarkers to predict treatment response. Specific single-nucleotide polymorphisms (SNPs) in the genes encoding endoplasmic reticulum aminopeptidases 1 and 2 (ERAP1 and ERAP2) have been associated with psoriasis and other immune-mediated diseases.

Objectives

To investigate the association between the ERAP1 and ERAP2 genotypes and response to secukinumab treatment in patients with psoriasis.

Methods

In total, 75 patients with plaque psoriasis were included. All patients were genotyped for the ERAP1 rs27524, rs27044, rs30187, rs2287987 and rs26653 SNPs, the ERAP2 rs2248374 SNP, and the status of the human leucocyte antigen HLA-C*06:02 gene.

Results

Our results demonstrated that individuals with specific ERAP1 and ERAP2 genotypes had a considerably lower response rate to secukinumab treatment. Patients with the ERAP2 rs2248374 GG genotype had a more than sixfold increased risk of treatment failure compared with patients with the rs2248374 AG or AA genotypes. Stratifying for HLA-C*06:02 status, the ERAP2 GG genotype pointed towards an increased risk of treatment failure among HLA-C*06:02-positive patients, although this was not statistically significant.

Conclusions

Taken together, this unique study breaks new ground by identifying distinct ERAP1 and ERAP2 gene variants that may serve as potential biomarkers for predicting the treatment response to secukinumab in patients with psoriasis. Notably, our data extend existing knowledge by linking specific ERAP1 and ERAP2 gene variants to treatment outcome.
Estimation of the rate constants for the radical addition of a trifluoromethyl radical to aryl-substituted vinyl triflates
Authors: Kawamoto Takuji , Hisayuki Mai , Kamimura Akio
Published: April 2024

The rate constants for the radical addition of a trifluoromethyl radical to aryl-substituted vinyl triflates have been determined by applying competition kinetics at a single concentration point. The rate constants range from 4.1× 106 to 5.6× 106 M−1 s−1 and depend on the electronic properties of the benzene rings on the aryl-substituted vinyl triflates.
The elephant’s Achilles’ heel: a case report of acute obstruction of frozen elephant trunk after proximal aortic dissection repair
Authors: Nienaber Stephan , Yuan Xun , Price Susanna , Rosendahl Ulrich , Nienaber Christoph A
Published: April 2024

Background

The frozen elephant trunk (FET) technique as a hybrid combining surgical and endovascular repair is an emerging concept to treat complex aortic dissection. Early experience showed technical feasibility and promising clinical outcomes. However, unsuspected complications still arise.

Case summary

A 25-year-old male presented to the emergency department with a 2-day history of chest pain. After exclusion of acute coronary syndrome, a computed tomography angiography (CTA) revealed Type A (DeBakey Type I) aortic dissection. The patient underwent median stenotomy for complete replacement of the ascending aorta, the aortic arch, and FET. Early after rewarming, the patient became unstable due to severe left ventricular dysfunction. Soon veno-arterial extracorporal membrane oxygenation (VA-ECMO) was required for circulatory support. The cause of deterioration remained unclear until repeated CTA showed acute obstruction of the FET. Invasive exploration confirmed a trans-FET gradient of 100 mmHg, successfully managed by repeated balloon inflation with resolution of both obstruction and gradient. The patient recovered completely without any sequela.

Discussion

While the mechanism of acute obstruction after FET remains subject to speculation, the rescue intervention of ballooning the obliteration on VA-ECMO was life-saving. Intraoperative ultrasound and videoscopic inspection may be instrumental before chest closure to avoid such critical events.
A case report of concurrent management of acute myocardial infarction complicated by left ventricular thrombus and ischaemic stroke
Authors: Kodama Yuka , Matsumoto Kenji , Kubota Hisashi , Furuya Onichi , Kawase Yoshio
Published: April 2024

Background

Left ventricular thrombus (LVT) formation is a serious complication of acute myocardial infarction (AMI) requiring complicated management strategies and collaboration among cardiologists, cardiovascular surgeons, and neurosurgeons.

Case summary

We present the case of an 83-year-old female patient with AMI. Emergency coronary angiography revealed subtotal occlusion of the proximal left anterior descending artery, and the patient was successfully treated with a drug-eluting stent. The following day, she suddenly developed loss of consciousness, global aphasia, and right hemiplegia. Brain magnetic resonance imaging revealed acute ischaemic cerebral infarction caused by multiple mobile LVT, as demonstrated by echocardiography. After a heart–brain team discussion, we decided to perform percutaneous mechanical thrombectomy. Successful recanalization was achieved with mechanical thrombectomy 2 h after presentation, which resulted in significant neurological recovery. Immediately after the thrombectomy, she was transferred to a cardiovascular surgery centre for surgical removal of multiple LV apical thrombi. Two weeks after the operation, the patient was discharged with the recovery of LV systolic function.

Discussion

Although AMI complicated by acute stroke caused by LVT remains a clinical challenge, a multidisciplinary approach is critically important for optimal care. Based on an urgent team discussion, we decided to perform endovascular thrombectomy for ischaemic stroke, followed by surgical removal of the LVT, requiring patient transportation to the cardiovascular surgery centre. Given that the heart and brain team-based approach remains confined to large, specialized centres, it might be beneficial to establish a community-based integrated heart–brain team that can address the growing needs of complex patients.
A new data infrastructure for family research and demographic analysis: the German Family Demography Panel Study (FReDA)
Authors: Hank Karsten , Gummer Tobias , Bujard Martin , Neyer Franz J , Pollak Reinhard , Spieß C Katharina , Wolf Christof , Christmann Pablo , Kunz Tanja , Lück Detlev , Naderi Robert , Nutz Theresa , Schmid Lisa , Thönnissen Carolin
Published: April 2024

This data brief introduces the German Family Demography Panel Study (FReDA; https://www.freda-panel.de/), a longitudinal, multi-actor database for family research. Major substantive fields addressed in the questionnaire include fertility-related attitudes and behaviours, reproductive health, work-family conflict, couples’ division of labour, gender roles, intimate relationships, separation and divorce, parenting and intergenerational relations, and well-being. FReDA is based on two initially independent samples: the newly drawn FReDA-GGS sample (n_recruitment = 37,777 respondents, aged 18–49 years), constituting the German contribution to the Generations and Gender Surveys (GGS-II), and the FReDA-pairfam sample (n = 6,216 respondents who originally participated in the German Family Panel [pairfam]). Both samples are fully integrated, using one survey instrument consisting of the harmonized GGS-II and pairfam questionnaires. Mainly web-based interviews, complemented by paper-based interviews, are conducted biannually, with one wave being split across two subwaves. We provide a short description of FReDA’s forerunners—the GGS and pairfam—and give an overview of FReDA’s design and content, its baseline wave (collected in 2021) and data releases, as well as a brief outlook on FReDA’s road ahead.
Online customized strategy for manufacturers to counter showrooming behavior in a dual-channel supply chain
Authors: Lei Qian , He Juan
Published: April 2024

Accepted by: M. Zied Babai

Showrooming refers to a behavior of consumer transferring from offline stores to online purchasing. Consumers’ showrooming behavior would affect not only the offline stores but also manufacturers in the long run. This study aims at putting forward an online customized strategy offered by a manufacturer to defeat the negative of showrooming in the context of a dual-channel supply chain where a manufacturer sells products online to consumers via a direct channel and wholesales products to an offline retailer, then the retailer sells products via an offline channel. Based on game theory and backward induction, optimal pricing decisions for the manufacturer and the retailer are established. It shows that consumers’ showrooming behavior decreases the selling prices and increases sales volumes in both the online direct channel and the offline channel. As further revealed, showrooming behavior would hurt the retailer under certain conditions and always damage the manufacturer. To mitigate the negative effects of showrooming, an online customized strategy is developed for the manufacturer. That is, the manufacturer would provide standard and customized products for online channel, allowing offline channel to sell only standard products. According to the results, online customized strategy would always damage the interests of the retailer, while customized strategy increases the profit of the manufacturer and increases the social welfare of the supply chain under certain circumstances.
Aberrant microbiomes are associated with increased antibiotic resistance gene load in hybrid mice
Authors: Jarquín-Díaz Víctor Hugo , Ferreira Susana Carolina Martins , Balard Alice , Ďureje Ľudovít , Macholán Milos , Piálek Jaroslav , Bengtsson-Palme Johan , Kramer-Schadt Stephanie , Forslund-Startceva Sofia Kirke , Heitlinger Emanuel
Published: April 2024

Antibiotic resistance is a priority public health problem resulting from eco-evolutionary dynamics within microbial communities and their interaction at a mammalian host interface or geographical scale. The links between mammalian host genetics, bacterial gut community, and antimicrobial resistance gene (ARG) content must be better understood in natural populations inhabiting heterogeneous environments. Hybridization, the interbreeding of genetically divergent populations, influences different components of the gut microbial communities. However, its impact on bacterial traits such as antibiotic resistance is unknown. Here, we present that hybridization might shape bacterial communities and ARG occurrence. We used amplicon sequencing to study the gut microbiome and to predict ARG composition in natural populations of house mice (Mus musculus). We compared gastrointestinal bacterial and ARG diversity, composition, and abundance across a gradient of pure and hybrid genotypes in the European House Mouse Hybrid Zone. We observed an increased overall predicted richness of ARG in hybrid mice. We found bacteria–ARG interactions by their co-abundance and detected phenotypes of extreme abundances in hybrid mice at the level of specific bacterial taxa and ARGs, mainly multidrug resistance genes. Our work suggests that mammalian host genetic variation impacts the gut microbiome and chromosomal ARGs. However, it raises further questions on how the mammalian host genetics impact ARGs via microbiome dynamics or environmental covariates.