bluuebunny/crossref_metadata_2025 huggingface dataset:
The professional background of a referring physician predicts the diagnostic yield of small bowel capsule endoscopy in suspected small bowel bleeding
Authors: Compare Debora , Sgamato Costantino , Rocco Alba , Coccoli Pietro , Donnarumma Durante , Marchitto Stefano Andrea , Cinque Sofia , Palmieri Pietro , Nardone Gerardo
Published: January 2024

Background and study aims The diagnostic yield of small-bowel capsule endoscopy (SBCE) in suspected small bowel bleeding (SSBB) is highly variable. Different reimbursement systems and equipment costs also limit SBCE use in clinical practice. Thus, minimizing non-diagnostic procedures is advisable. This study aimed to assess the SBCE diagnostic yield and identify factors predicting diagnostic findings in a cohort of patients with SSBB.

Patients and methods In this retrospective cohort study, we analyzed the medical records of patients who consecutively underwent SBCE for SSBB over 9 years. By logistic regression, we identified covariates predicting diagnostic findings at SBCE. Finally, we performed a post-hoc cost analysis based on previous gastroenterologist or endoscopist consultations versus direct SBCE ordering by other specialists.

Results The final analysis included 584 patients. Most SBCEs were
ordered by a gastroenterologist or endoscopist (74%). The number of SBCEs without any finding
was significantly lower in the gastroenterologist/endoscopist group P<0.001). The SBCE diagnostic yield ordered by a gastroenterologist or
endoscopist was significantly higher than that by other specialists (63% vs 52%, odds ratio
[OR] 1.57; 95% confidence interval [CI] 1.07–2.26, P=0.019). At
multivariate analysis, older age (OR 1.7, 95%CI 1.2–2.4, P=0.005),
anemia (OR 4.9, 95%CI 1.9–12, P=0.001), small bowel transit time
(OR 1, 95%CI 1–1.02, P=0.039), and referring physician (OR 1.8,
95%CI 1.1–2.7, P=0.003) independently predicted diagnostic
findings. Implementing prior gastroenterologist or endoscopist referral vs direct SBCE
ordering would reduce medical expenditures by 16%.

Conclusions The professional background of referring physicians significantly improves the diagnostic yield of SBCE and contributes to controlling public health costs.
Safety Profile of Intra-Arterial Tirofiban as a Rescue Therapy during Mechanical Thrombectomy in Acute Ischemic Stroke
Authors: Athiyappan Karthikeyan Muthugounder , Cherian Mathew , Mehta Pankaj , Poyyamoli Santhosh , Reddy Nikhil Handihal , Jayaraj Anupchakravarthy , Palathingal Shaheer Ali
Published: January 2024

Purpose This article studies the safety profile and role of intra-arterial (IA) tirofiban as a rescue therapy in acute ischemic stroke (AIS) patients undergoing mechanical thrombectomy.

Methods This is a retrospective observational study conducted among AIS patients with large vessel occlusion (LVO) eligible for endovascular revascularization and in whom IA tirofiban is given as rescue therapy. If the target vessel shows reocclusion following initial recanalization, flow limiting or significant residual stenosis after thrombectomy, or requires balloon angioplasty or stenting, IA tirofiban at a dose of 0.4 μg/kg/min was administered through the microcatheter in the target vessel followed by intravenous infusion of 0.1 μg/kg/min. The primary safety measure of the study was the incidence of symptomatic hemorrhage.

Results The total number of patients in the study group was 82, 36 were in the tirofiban group and 46 were in the non-tirofiban group. Immediate successful reperfusion was achieved in 31 patients (86.1%) and 41 patients (89%) in the tirofiban and non-tirofiban groups, respectively. Note that 19.4 and 25% of patients in the tirofiban group required adjunct techniques of angioplasty and stenting, respectively. Also, 2.7% patient in the tirofiban group had a symptomatic hemorrhage, while 8.7% in the non-tirofiban group had symptomatic intracranial hemorrhage. On multinomial logistic regression, history of transient ischemic attack, truncal occlusion and watershed infarct pattern predicted the usage of IA tirofiban during mechanical thrombectomy.

Conclusion Usage of IA tirofiban with or without adjunct techniques as a rescue therapy during mechanical thrombectomy in LVO improved recanalization rates without increasing the risk of symptomatic hemorrhage.
Early Prenatal Diagnosis of Cornelia de Lange's Syndrome with Whole-Exome Sequencing: A Case Report
Authors: Iftikhar Amna , Barnes Kathleen , Figueroa Melissa , Francis Antonia P.
Published: January 2024

Cornelia de Lange's syndrome (CDLS) is a multisystem genetic syndrome characterized by well-defined physical, intellectual, and behavioral characteristics. The diagnosis of CDLS is typically done clinically after birth; however, recent studies have demonstrated the ability to use prenatal ultrasound and whole-exome sequencing to diagnose CDLS prenatally. Here we present a prenatal case in which multiple fetal anomalies were identified on ultrasound at 20 weeks of gestation. Use of whole-exome sequencing allowed for successful diagnosis of CDLS in this fetus prenatally.
The Combined Influence of Maternal Medical Conditions on the Risk of Primary Cesarean Delivery
Authors: Fresch Robert , Stephens Kendal , DeFranco Emily
Published: January 2024

Background Common maternal medical comorbidities such as hypertensive disorders, diabetes, tobacco use, and extremes of maternal age, body mass index, and gestational weight gain are known individually to influence the rate of cesarean delivery. Numerous studies have estimated the risk of individual conditions on cesarean delivery.

Objective To examine the risk for primary cesarean delivery in women with multiple maternal medical comorbidities to determine the cumulative risk they pose on mode of delivery.

Study Design In this population-based retrospective cohort study, we analyzed data from Ohio live birth records from 2006 to 2015 to estimate the influence of individual and combinations of maternal comorbidities on rates of singleton primary cesarean delivery. The exposures were individual and combinations of maternal medical conditions (chronic hypertension [CHTN], gestational hypertension, pregestational diabetes, gestational diabetes, tobacco use, advanced maternal age, and maternal obesity) and outcomes were rates and adjusted relative risk (aRR) of primary cesarean delivery.

Results There were 1,463,506 live births in Ohio during the study period, of which 882,423 (60.3%) had one or more maternal medical condition, and of those 243,112 (27.6%) had primary cesarean delivery. The range of rates and aRR range of primary cesarean delivery were 13.9 to 29.3% (aRR 0.78–1.68) in singleton pregnancies with a single medical condition, and this increased to 21.9 to 48.6% (aRR 1.34–3.87) in pregnancies complicated by multiple medical comorbidities. The highest risk for primary cesarean occurred in advanced maternal age, obese women with pregestational diabetes, and CHTN.

Conclusion A greater number of maternal medical comorbidities during pregnancy is associated with increasing cumulative risk of primary cesarean delivery. These data may be useful in counseling patients on risk of cesarean during pregnancy.
Small Cell Cervical Carcinoma in Pregnancy: Therapeutic Options for an Aggressive Cancer Diagnosis
Authors: Savelli Binsted Alyssa , Kassem Zeinab , Le David , de Veciana Margarita
Published: January 2024

Neuroendocrine small cell cervical carcinoma is an aggressive cancer which accounts for approximately 1 to 3% of all cervical neoplasms. Therapy must be altered in pregnancy to optimize maternal–fetal outcomes. A 39-year-old woman presented for a routine prenatal visit and was noted to have a grossly abnormal cervix. Cervical biopsies confirmed small cell carcinoma. At 19 weeks' gestation, chemotherapy was initiated. The patient delivered at 34 weeks' gestation to initiate radiation therapy. Six months later, she was diagnosed with metastatic disease and died from cancer complications. In pregnancy, treatment modalities for small cell cervical carcinoma are based on the patient's gestational age at diagnosis. While aggressive early treatment is preferred, platinum-based chemotherapy can be initiated in the second trimester and radiation therapy delayed until delivery. Small cell cervical carcinoma complicating pregnancy requires aggressive treatment. Chemotherapy in the second trimester with planned delayed radiation therapy, may optimize fetal outcomes.
Intrahepatic Cholestasis of Pregnancy and Transaminitis in Women with COVID-19: A Case Series
Authors: Waldrop Anne R. , Henkel Andrea , Lee Kelley B. , Druzin Maurice L. , Aziz Natali , El-Sayed Yasser , Lyell Deirdre J.
Published: January 2024

Objective The four initial severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected pregnant women presenting at term gestation to our institution presented with transaminitis. Three of the four were diagnosed with intrahepatic cholestasis of pregnancy (IHCP). Growing evidence exists of an associated transaminitis in nonpregnant SARS-CoV-2 patients. However, there are limited data of hepatic involvement of SARS-CoV-2 in pregnancy, and no previous studies have assessed the association with IHCP in patients with coronavirus disease 2019 (COVID-19).

Study Design This was a retrospective, single-center case series of four consecutive pregnant women with a positive result for SARS-CoV-2 presenting with transaminitis in third trimester.

Results The clinical courses of four pregnant women with COVID-19 and transaminitis, three of four of whom were diagnosed with IHCP, are described. Testing for SARS-CoV-2 was done through a reverse transcription polymerase chain reaction test of a nasopharyngeal swab.

Conclusion As we await larger studies ascertaining the incidence of IHCP in SARS-CoV-2, this prevalence highlights the importance of diagnosing IHCP among women with COVID-19 as a potential etiology of transaminitis, as IHCP risks may be ameliorated with earlier delivery. Moreover, delineating a hepatobiliary association in pregnancy may provide further information about the mechanism of liver impairment in SARS-CoV-2 in all patients.
Arthroscopic Treatment of Traumatic Isolated Volar Dislocation of the Distal Radioulnar Joint: Case Report and Management Proposal
Authors: Kaempf Ricardo , Atzei Andrea , Brunelli João Pedro Farina , Delgado Pedro J
Published: January 2024

Background Traumatic isolated dislocation of the distal radioulnar joint (DRUJ) has always been an injury recognized for its rarity, misdiagnosis, and possibility of inability to be reduced at emergency care. As a result, little has been discussed so far about the guidelines and routines for its treatment.

It is known that some degree of injury to the triangular fibrocartilage (TFC) is required for a DRUJ to be dislocated. However, there is no evidence to prove that this injury will cause any degree of DRUJ instability following reduction.

Methods We show a case of a patient with traumatic isolated volar dislocation of the DRUJ in which, after failure in the attempt to reduce it in the emergency room, surgical treatment was performed using an arthroscopic method.

Results Computed tomography and magnetic resonance imaging axial sections showed the impaction of the distal ulna, with its groove to the extensor carpi ulnaris tendon blocked in the anterior labrum of the sigmoid notch of the radius. Arthroscopy before reduction showed that the distal portion of the TFC was intact, with damage to the foveal insertion (Palmer Type 1B, Atzei Class 3). After joint reduction, a loop-shaped repair of the TFC foveal lesion was performed through the central disc and attached to the distal ulna footprint. The patient presented good progression, with quick recovery, and no serious complications or the need for a second surery.

Conclusion We indicate the use of arthroscopy in patients with irreducible isolated volar dislocation, with subacute or chronic presentation, who have to be managed in the operating room. It is a useful method for diagnosing and repairing the TFC injury. This will prevent possible complications and provide faster recovery, mainly reducing the time of immobilization.
Bicoastal Spontaneous Coronary Artery Dissection: A Therapeutic Dilemma
Authors: Nguyen Pham Ann B. , De Zoysa Madushka Y. , Ghoshhajra Brian B. , Scott Nandita S. , Hameed Afshan B.
Published: January 2024

Due to the potential for severe maternal morbidity and even mortality, pregnancy-associated spontaneous coronary artery dissection (P-SCAD) often presents as a clinical conundrum. While current recommendations encourage coronary interventions when medically indicated even during pregnancy, the hesitation still understandably exists. Meanwhile, given the rarity of the condition, the guidelines for management are still based on expert consensus.

We present a case of P-SCAD in a 38-year-old woman with initial presentation at 28 weeks' gestation and recurrence at 9 days postpartum. A unique complication of this case is its transcontinental nature: the initial event occurred while the patient was on vacation across the country from her home. Questions arose not only with regard to her immediate management and care but also when she would be able to travel and how her complex care would be continued cross-country.

This case raised important questions regarding the antepartum management of acute coronary syndrome (ACS). It also highlights the importance of multidisciplinary care, especially with a cardio-obstetrics team, in the management of P-SCAD and emphasizes the role for universal screening for cardiac diseases in pregnancy.
Unusual Presentations of Sellar and Suprasellar Space Occupying Lesion: Our Institutional Experience
Authors: Giridharan Ramalingam , Kumar Nirmal , Srisaravanan J.
Published: January 2024

A pituitary abscess (PA) is a rare intracranial lesion. It is a critical disorder caused by an infectious process where purulent material accumulates inside the sella turcica. It occurs either as a primary disease or because of an infection and is associated with poor prognosis. In this article, we share our experience with PA. At our institution, we operated on five cases of pituitary abscess since 2016. All the cases presented with bitemporal hemianopia and headache. None of them had fever. Pituitary hormones were normal except in two patients with a previous history of hypothyroidism. Magnetic resonance imaging (MRI) of the brain showed pituitary macroadenoma. They underwent the endoscopic transnasal transsphenoidal approach. Postoperatively their vision has improved. Endocrine functions were normal in all the patients following surgery. Culture sensitivity was sterile in all the patients. Diagnosis of pituitary abscess is highly difficult before surgery. Hence, the diagnosis should be considered when a patient presents with fever, headache, and signs of pituitary dysfunction and meningeal inflammation. Surgical and medical management leads to a lower mortality rate and a higher probability of hormone function recovery.
Fabricating AC/DC nanogenerators based on single ZnO nanowires by using a nanomanipulator in a scanning electron microscope
Authors: Liu Mei , He Mengfan , Djoulde Aristide , Kong Lingdi , Su Weilin , Bai Xin , Chen Jinbo , Rao Jinjun , Wang Zhiming
Published: January 2024

Single zinc oxide nanowires (ZnO NWs) are promising for nanogenerators because of their excellent semiconducting and piezoelectric properties, but characterizing the latter efficiently is challenging. As reported here, an electrical breakdown strategy was used to construct single ZnO NWs with a specific length. With the high operability of a nanomanipulator in a scanning electron microscope, ZnO-NW-based two-probe and three-probe structures were constructed for fabricating AC/DC nanogenerators, respectively. For a ZnO NW, an AC output of between −15.31 mV and 5.82 mV was achieved, while for a DC nanogenerator, an output of ∼24.3 mV was realized. Also, the three-probe structure’s output method was changed to verify the distribution of piezoelectric charges when a single ZnO NW is bent by a probe, and DC outputs of different amplitudes were achieved. This study provides a low-cost, highly convenient, and operational method for studying the AC/DC output characteristics of single NWs, which is beneficial for the further development of nanogenerators.
Low voltage visible light modulation for three colors (red, green, blue) by sputtered lithium niobate thin film
Authors: Hara Hiroki , Yoshinari Jiro , Sasaki Kenji , Kikukawa Takashi , Take Hiroshi , Mino Tetsuya , Shimura Atsushi , Takagi Yasuhiro , Fukuzawa Hideaki
Published: January 2024

In this study, lithium niobate (LN) optical modulator devices were fabricated using cost-effective sputtered LN thin films. We successfully achieved a significantly small product of half-wave voltage and interaction electrode length (VπL) of 1.2, 1.0, and 0.75 V cm using red (λ = 638 nm), green (λ = 520 nm), and blue (λ = 473 nm) laser light, respectively. This small VπL is owing to the use of a low dielectric material of LaAlSiInOx for buffer insulator between LN waveguides and electrodes, and the change of geometrical configuration of the electrode. Thus, fabricating visible light modulators at low cost can be realized, and sputtered LN thin films can be adopted for visible light communications and consumer-based applications.
Simulation of proton-induced primary displacement damage in GaAs under different ambient temperatures
Authors: Xing Tian , Liu Shuhuan , Song Ci , Wang Xuan , Adekoya Mathew Adefusika , Wang Chao , Li Haodi , Meng Fanjun , Du Xiaozhi , Sun Yunfeng , Zhu Shijie , Wang Lipeng , Chen Wei , Li Kang , Zheng Xiaohai
Published: January 2024

The performance of on-orbit GaAs-based solar cells is susceptible to the displacement damage effect. The proton-induced primary displacement damage in GaAs on a geosynchronous equatorial orbit (GEO) was simulated and analyzed by combining the Monte Carlo (MC) and molecular dynamics (MD) methods. The MC simulation provided the distribution of primary knock-on atoms (PKAs) in GaAs induced by GEO-related protons to the MD simulation. In MD simulations, the effects of radiation fluence and ambient temperature on the displacement damage were considered. The simulation results showed that GEO-related protons generated a significant number of PKAs within an energy range of below 10 keV in GaAs. The high-fluence radiation emulated by the binary PKA could generate more point defects and cluster defects in GaAs than the low-fluence radiation emulated by single PKAs. As compared to room temperature (300 K), both a low (100 K) and high (500 K) ambient temperature could deteriorate the displacement damage. In addition, a high ambient temperature of 500 K could induce widespread thermal spikes in GaAs as compared to 100 and 300 K. This work can provide useful insight into the proton-induced displacement damage in GaAs and the radiation hardening of GaAs-based photoelectric devices in space.
Influence of plasticity on the magnetic-field-induced bending deformation in a magneto-active elastomer with superparamagnetic nanoparticles
Authors: Kalita V. M. , Dzhezherya Yu I. , Cherepov S. V. , Skirta Yu B. , Kyryliuk A. V. , Reshetniak S. O. , Bodnaruk A. V. , Ryabchenko S. M.
Published: January 2024

The influence of residual plastic deformation on the bending deformation of a magnetoactive elastomer (MAE) beam with non-coercive superparamagnetic manganite (La0.6Ag0.2Mn1.2O3) nanoparticles induced by a transverse uniform magnetic field has been studied. It was found that the MAE bending induced by the magnetic field switching-on/switching-off is mainly cyclic elastic. Plastic deformation leads to the emergence of residual bending and hysteresis in the field dependence of the bending. It was shown that the residual bending that appears after the first magnetic field switch-on eliminates the uncertainty of the bending direction at the next magnetization. Due to the residual plastic deformation, the bending direction of the superparamagnetic MAE with nanoparticles does not change when the direction of the applied magnetic field is inverted, in contrast to the MAE with microparticles where the uncertainty of the bending direction is eliminated due to the residual magnetization of weakly coercive ferromagnetic microparticles; therefore, the bending direction changes its sign with magnetic field reversion. In the low fields, the bending value for the MAEs with superparamagnetic particles is proportional to the square of the magnetic field strength. Model estimates on the residual deformation influence on the beam bending at beam magnetization reversal were obtained.
Optimizing separate and combined grids for cost-effective hybrid renewable energy electrification in Mogadishu, Somalia
Authors: Elmi Yonis Khalif , Şenol Mehmet , Kuşaf Mehmet
Published: January 2024

Expanding access to affordable, reliable, and sustainable electricity is an urgent priority in Somalia, which suffers from high energy costs and climate vulnerability despite negligible emissions. Therefore, this study employs MATLAB simulation software and three algorithms—particle swarm optimization (PSO), genetic algorithm, and simulated annealing—to determine optimal separate and combined grid designs for a hybrid renewable energy system in Mogadishu, Somalia. Four system configurations are assessed, namely, utilities—diesel-alone, Photovoltaic (PV)–diesel hybrid, wind–diesel hybrid, and PV–wind–diesel hybrid across the grids of three utilities—Benadir Electric Company, Mogadishu Power Supply, and Blue-Sky Energy. The algorithms evaluate technical feasibility, economic viability, and system reliability to identify the most suitable configurations. Forty-eight systems are analyzed. The combined PV/wind/diesel grid optimized with PSO is most effective, reducing the net present cost by 32%–47% and levelized cost of electricity by 41%–60% compared to diesel-only systems while maintaining reliability. Greenhouse gas emissions decrease by 38%–59% with the hybrid system.
Pareto exponentiated log-logistic distribution (PELL) with an application to Covid-19 data
Authors: Ihtisham Shumaila , Manzoor Sadaf , Alamgir  , Alamri Osama Abdulaziz , Qureshi Muhammad Nouman
Published: January 2024

Recently, the Covid-19 pandemic has caused tremendous trauma over the world, leading to psychological and behavioral harm in addition to social and economic instabilities. Even though the pandemic’s statistical analysis is still in progress, it is essential to fit Covid-19 data using statistical models to prevent further harm. In order to model Covid-19 data, the study suggests a novel family of distributions called the exponentiated log-logistic family. The basic Pareto distribution is transformed as a special case, and certain properties of the proposed distribution are discussed. To estimate the model parameters, the maximum likelihood estimation approach is used. Moreover, a simulation study is conducted to ensure the consistency of parameter estimates. Three real-world datasets relevant to the Covid-19 pandemic are examined to demonstrate the applicability of the suggested approach. The proposed model is shown to be more flexible and provides an improved fit to describe the Covid-19 data when compared to various alternative forms of Pareto distribution.
Development of the Langmuir probe under q-distribution for NCST
Authors: Xiao Donghua , Chen Xiaochang , Liu Sanqiu , Chen Hui , Xiong Yuzhen
Published: January 2024

The Langmuir probe is one of the important diagnostic methods for measuring the edge plasma parameters of tokamak. A quadruple Langmuir probe (QLP) system was designed and built on the NanChang Spherical tokamak (NCST). The nonextensive single Langmuir probe (NSLP) theory [Qiu et al., Phys. Rev. E 101, 043206 (2020)] is extended to the nonextensive QLP (NQLP) theory, and then the electron temperature and electron number density of the edge plasma in NCST are obtained. The results show that the differences between the edge plasma parameters (electron temperature and number density) under the nonextensive statistics and those under the Maxwellian distribution are more than 50%, which indicates that the nonextensive parameters have an important influence on the actual measurement of QLP.
Magnetization process of antiferromagnetic quantum spin chains with the biquadratic exchange interaction
Authors: Sakai Tôru
Published: January 2024

The magnetization processes of the S = 3/2 and S = 2 antiferromagnetic chains with the biquadratic interaction are investigated using the numerical diagonalization of the finite-size cluster. It is found that the system does not exhibit the spin nematic phase, which was predicted to occur for the S = 1 antiferromagnetic chain. Instead, the present analysis reveals that the quantum spin triatic and quatic liquid phases appear below the saturation magnetization for sufficiently large negative biquadratic interaction, for S = 3/2 and S = 2 chains, respectively. In addition it is also found that the magnetization jump up to the saturation magnetization appears for the small negative biquadratic interaction. The phase diagrams with respect to the negative biquadratic interaction and the magnetization are presented for the S = 3/2 and S = 2 antiferromagnetic chains.
Enhanced heating efficiency for hollow Fe3O4 spherical submicron particles
Authors: Tsuji Takahiro , Kobayash Satoru
Published: January 2024

We have investigated ac hysteresis loops of hollow Fe3O4 submicron particles with variable particle size of d = 100−696 nm by micromagnetic simulations to investigate the possible application to magnetic hyperthermia. For the hollow particle with the inner/outer diameter ratio of γ = 0.5, the hysteresis loss increases with increasing d and maximizes at d ∼ 300 nm, whereas the hysteresis loss generally increases with γ, but its behavior strongly depends on d. A specific absorption rate, calculated from the loop area at the field frequency of 500 kHz, attains 560 W/g for d = 296 nm and γ = 0.5, which is comparable to that for conventional superparamagnetic nanoparticles. This enhanced specific absorption ratio for the hollow particles can be explained by strong irreversibility between vortex states with different orientation of the vortex core, i.e. along the magnetic field and ⟨111⟩ easy axes.
On the origin of systematic errors in VSM torque curves
Authors: Sapkota Arjun , Rodriguez Leo , C. Binod D. , Dieckow Kolton , Howlader Chandan Q. , Geerts Wilhelmus J. , Tate Jitendra
Published: January 2024

Magnetic anisotropy (MA) is a basic and crucial magnetic property which describes how the magnetic properties change with field angle in a magnetic composite. Torque measurements are normally used to measure a sample’s anisotropy constant and can be determined directly using a torque magnetometer (TM) or indirectly using a vibrating sample magnetometer (VSM). Most TM only operate at room temperature. However, a biaxial VSM allows straightforward torque measurements at varying temperatures. VSM torque curves comprise a 2θ background caused by small misalignments of the sample on the sample rod, and/or a non-azimuthal symmetric sample shape. These errors originate from the position dependence of the pickup coil sensitivity matrix. Here, the magnetic torque of a strontium ferrite/PA-12 3D printed samples was explored using biaxial VSM and compared to measurements done with a true torque magnetometer. Torque curves were taken from 16-22kOe every 2kOe on a 4.8 mm wire and a 1.23 mm dot sample using a MicroSense EZ9 VSM. Fourier analysis was used to determine the second harmonics from each torque curve. The biaxial torque curves of the wire samples have a much larger torque amplitude which is mainly due to the crosstalk of the y-coil set. Crosstalk originates from the non-azimuthal symmetric shape of the sample and due to the wobble originating from small sample misalignments on the sample rod. Background can be minimized by using samples with near cylindrical symmetry and using a microscope when mounting the sample on the sample rod.
Analysis of variable inductor employing vegetable-based transformer oil with magnetic nanoparticles
Authors: Lee Ho-Young , Hong Seung-Geon , Baek Myung-Ki
Published: January 2024

Variable inductors using magnetorheological fluids have recently been successfully applied to power-conversion devices; however, the thermal properties of Vegetable oil-based Magnetic Nanofluids (VMNFs) have not been investigated. In this study, the temperature characteristics of a variable inductor embedded with a VMNF were analyzed by developing a multiphysics analysis method and verified experimentally. To analyze the temperature distribution efficiently, a coupled analysis of the Magnetoquasistatic (MQS) field and steady-state heat transfer field based on the finite-element method was performed. The B-H curves of the VMNF and ferrite core were obtained via magnetic property measurement experiments, and the input waveforms were measured from the current and high-frequency pulse voltages applied to the variable inductor of the DC–DC converter. To predict the temperature rise of the VMNF-gap variable inductor, the power dissipation was determined using the Steinmetz experimental equation modified by the Bertotti model in the electronic system solver and input as a heat source in the steady-state heat-transfer analysis. The temperature increase predicted by the multiphysics analysis method agreed well with the experimental data, and an increasing the concentration of magnetic nanoparticles had a cooling effect. The developed MQS–thermal field coupled analytical method and the cooling properties of VMNFs can be applied to the design of power-conversion devices operating with high-frequency power sources.
Plasmon-enhanced multi-photon excited photoluminescence of Au, Ag, and Pt nanoclusters
Authors: Bornacelli J , Torres-Torres C , Crespo-Sosa A , Reyes-Esqueda J A , Oliver A
Published: January 2024

In this work, we have studied the multi-photon excited photoluminescence from metal nanoclusters (NCs) of Au, Ag and Pt embedded in Al2O3 matrix by ion implantation. The thermal annealing process allows to obtain a system composed of larger plasmonic metal nanoparticles (NPs) surrounded by photoluminescent ultra-small metal NCs. By exciting at 1064 nm, visible emission, ranging from 450 to 800 nm, was detected. The second and fourth-order nature of the multiphoton process was verified in a power-dependent study measured for each sample below the damage threshold. Experiments show that Au and Ag NCs exhibit a four-fold enhanced multiphoton excited photoluminescence with respect to that observed for Pt NCs, which can be explained as a result of a plasmon-mediated near-field process that is of less intensity for Pt NPs. These findings provide new opportunities to combine plasmonic nanoparticles and photoluminescent nanoclusters inside a robust inorganic matrix to improve their optical properties. Plasmon-enhanced multiphoton excited photoluminescence from metal nanoclusters may find potential application as ultrasmall fluorophores in multiphoton sensing, and in the development of solar cells with highly efficient energy conversion modules.
Glimm’s method and density of wild data for the Euler system of gas dynamics
*
Authors: Chiodaroli Elisabetta , Feireisl Eduard
Published: January 2024

We adapt Glimm’s approximation method to the framework of convex integration to show density of wild data for the (complete) Euler system of gas dynamics. The desired infinite family of entropy admissible solutions emanating from the same initial data is obtained via convex integration of suitable Riemann problems pasted with local smooth solutions. In addition, the wild data belong to BV class.
Respiratory motion modelling for MR-guided lung cancer radiotherapy: model development and geometric accuracy evaluation
Authors: Eiben Björn , Bertholet Jenny , Tran Elena H , Wetscherek Andreas , Shiarli Anna-Maria , Nill Simeon , Oelfke Uwe , McClelland Jamie R
Published: January 2024

Objective. Respiratory motion of lung tumours and adjacent structures is challenging for radiotherapy. Online MR-imaging cannot currently provide real-time volumetric information of the moving patient anatomy, therefore limiting precise dose delivery, delivered dose reconstruction, and downstream adaptation methods. Approach. We tailor a respiratory motion modelling framework towards an MR-Linac workflow to estimate the time-resolved 4D motion from real-time data. We develop a multi-slice acquisition scheme which acquires thick, overlapping 2D motion-slices in different locations and orientations, interleaved with 2D surrogate-slices from a fixed location. The framework fits a motion model directly to the input data without the need for sorting or binning to account for inter- and intra-cycle variation of the breathing motion. The framework alternates between model fitting and motion-compensated super-resolution image reconstruction to recover a high-quality motion-free image and a motion model. The fitted model can then estimate the 4D motion from 2D surrogate-slices. The framework is applied to four simulated anthropomorphic datasets and evaluated against known ground truth anatomy and motion. Clinical applicability is demonstrated by applying our framework to eight datasets acquired on an MR-Linac from four lung cancer patients. Main results. The framework accurately reconstructs high-quality motion-compensated 3D images with 2 mm3 isotropic voxels. For the simulated case with the largest target motion, the motion model achieved a mean deformation field error of 1.13 mm. For the patient cases residual error registrations estimate the model error to be 1.07 mm (1.64 mm), 0.91 mm (1.32 mm), and 0.88 mm (1.33 mm) in superior-inferior, anterior-posterior, and left-right directions respectively for the building (application) data. Significance. The motion modelling framework estimates the patient motion with high accuracy and accurately reconstructs the anatomy. The image acquisition scheme can be flexibly integrated into an MR-Linac workflow whilst maintaining the capability of online motion-management strategies based on cine imaging such as target tracking and/or gating.
Development of a Monte Carlo-based scatter correction method for total-body PET using the uEXPLORER PET/CT scanner
Authors: Bayerlein Reimund , Spencer Benjamin A , Leung Edwin K , Omidvari Negar , Abdelhafez Yasser G , Wang Qian , Nardo Lorenzo , Cherry Simon R , Badawi Ramsey D
Published: January 2024

Objective. This study presents and evaluates a robust Monte Carlo-based scatter correction (SC) method for long axial field of view (FOV) and total-body positron emission tomography (PET) using the uEXPLORER total-body PET/CT scanner. Approach. Our algorithm utilizes the Monte Carlo (MC) tool SimSET to compute SC factors in between individual image reconstruction iterations within our in-house list-mode and time-of-flight-based image reconstruction framework. We also introduced a unique scatter scaling technique at the detector block-level for optimal estimation of the scatter contribution in each line of response. First image evaluations were derived from phantom data spanning the entire axial FOV along with image data from a human subject with a large body mass index. Data was evaluated based on qualitative inspections, and contrast recovery, background variability, residual scatter removal from cold regions, biases and axial uniformity were quantified and compared to non-scatter-corrected images. Main results. All reconstructed images demonstrated qualitative and quantitative improvements compared to non-scatter-corrected images: contrast recovery coefficients improved by up to 17.2% and background variability was reduced by up to 34.3%, and the residual lung error was between 1.26% and 2.08%. Low biases throughout the axial FOV indicate high quantitative accuracy and axial uniformity of the corrections. Up to 99% of residual activity in cold areas in the human subject was removed, and the reliability of the method was demonstrated in challenging body regions like in the proximity of a highly attenuating knee prosthesis. Significance. The MC SC method employed was demonstrated to be accurate and robust in TB-PET. The results of this study can serve as a benchmark for optimizing the quantitative performance of future SC techniques.
The influence of cardiac arrhythmias on the detection of heartbeats in the photoplethysmogram: benchmarking open-source algorithms
Authors: Jeanningros Loïc , Le Bloa Mathieu , Teres Cheryl , Herrera Siklody Claudia , Porretta Alessandra , Pascale Patrizio , Luca Adrian , Solana Muñoz Jorge , Domenichini Giulia , Meister Théo A , Soria Maldonado Rodrigo , Tanner Hildegard , Vesin Jean-Marc , Thiran Jean-Philippe , Lemay Mathieu , Rexhaj Emrush , Pruvot Etienne , Braun Fabian
Published: January 2024

Objective. Cardiac arrhythmias are a leading cause of mortality worldwide. Wearable devices based on photoplethysmography give the opportunity to screen large populations, hence allowing for an earlier detection of pathological rhythms that might reduce the risks of complications and medical costs. While most of beat detection algorithms have been evaluated on normal sinus rhythm or atrial fibrillation recordings, the performance of these algorithms in patients with other cardiac arrhythmias, such as ventricular tachycardia or bigeminy, remain unknown to date. Approach. The PPG-beats open-source framework, developed by Charlton and colleagues, evaluates the performance of the beat detectors named QPPG, MSPTD and ABD among others. We applied the PPG-beats framework on two newly acquired datasets, one containing seven different types of cardiac arrhythmia in hospital settings, and another dataset including two cardiac arrhythmias in ambulatory settings. Main Results. In a clinical setting, the QPPG beat detector performed best on atrial fibrillation (with a median F
1 score of 94.4%), atrial flutter (95.2%), atrial tachycardia (87.0%), sinus rhythm (97.7%), ventricular tachycardia (83.9%) and was ranked 2nd for bigeminy (75.7%) behind ABD detector (76.1%). In an ambulatory setting, the MSPTD beat detector performed best on normal sinus rhythm (94.6%), and the QPPG detector on atrial fibrillation (91.6%) and bigeminy (80.0%). Significance. Overall, the PPG beat detectors QPPG, MSPTD and ABD consistently achieved higher performances than other detectors. However, the detection of beats from wrist-PPG signals is compromised in presence of bigeminy or ventricular tachycardia.
An interpretable shapelets-based method for myocardial infarction detection using dynamic learning and deep learning
Authors: Qu Jierui , Sun Qinghua , Wu Weiming , Zhang Fukai , Liang Chunmiao , Chen Yuguo , Wang Cong
Published: January 2024

Objective. Myocardial infarction (MI) is a prevalent cardiovascular disease that contributes to global mortality rates. Timely diagnosis and treatment of MI are crucial in reducing its fatality rate. Currently, electrocardiography (ECG) serves as the primary tool for clinical diagnosis. However, detecting MI accurately through ECG remains challenging due to the complex and subtle pathological ECG changes it causes. To enhance the accuracy of ECG in detecting MI, a more thorough exploration of ECG signals is necessary to extract significant features. Approach. In this paper, we propose an interpretable shapelet-based approach for MI detection using dynamic learning and deep learning. Firstly, the intrinsic dynamics of ECG signals are learned through dynamic learning. Then, a deep neural network is utilized to extract and select shapelets from ECG dynamics, which can capture locally specific ECG changes, and serve as discriminative features for identifying MI patients. Finally, the ensemble model for MI detection is built by integrating shapelets of multi-dimensional ECG dynamic signals. Main results. The performance of the proposed method is evaluated on the public PTB dataset with accuracy, sensitivity, and specificity of 94.11%, 94.97%, and 90.98%. Significance. The shapelets obtained in this study exhibit significant morphological differences between MI and healthy subjects.
Electrostatic-driven soft air pump with segmented electrodes
Authors: Zhao Jindong , Xu Ming , Zhang Yongfa , Yu Tang , Sun Hualiang
Published: January 2024

Pneumatic soft robots have become a popular research area for future robots because of their lightweight, high efficiency, non-pollution, and high reliability. However, the pneumatic pump, which is the ‘heart’ of these robots, is large in size, heavy in weight, noisy in operation, and must be separated from the robot body, which seriously affects the portability and autonomy of the robot. Portable soft pumps fabricated using smart materials provide a viable solution to the above challenges. We present a segmented electrode pump (SEP) driven by electrostatic forces, which combines the advantages of an electro-pneumatic pump (EPP) and an enhanced electrode structure. Compared with the EPP, the developed SEP showed improved characteristics in terms of higher specific flow rate output (1.67 ml s∙g−1), higher specific pressure output (0.483 kPa g−1) and lower power consumption (24 mW). The proposed SEP is expected to provide new solutions to the challenges of embedding air sources and facilitating air supply flexibility, and opens up new opportunities for fully flexible robots.
Quantum imaging beyond the standard-quantum limit and phase distillation
Authors: Schaffrath Simon , Derr Daniel , Gräfe Markus , Giese Enno
Published: January 2024

Quantum sensing using non-linear interferometers (NLIs) offers the possibility of bicolour imaging, using light that never interacted with the object of interest, and provides a way to achieve phase supersensitivity, i.e. a Heisenberg-type scaling of the phase uncertainty. Such a scaling behaviour is extremely susceptible to noise and only arises at specific phases that define the optimal working point (WP) of the device. While phase-shifting algorithms are to some degree robust against the deleterious effects induced by noise they extract an image by tuning the interferometer phase over a broad range, implying an operation beyond the WP. In our theoretical study, we investigate both the spontaneous and the high-gain regime of operation of an NLI. In fact, in the spontaneous regime using a distillation technique and operating at the WP leads to a qualitatively similar behaviour. In the high-gain regime, however, typical distillation techniques inherently forbid a scaling better than the standard-quantum limit, as a consequence of the photon statistics of squeezed vacuum. In contrast, an operation at the WP still may lead to a sensitivity below shot noise, even in the presence of noise. Therefore, this procedure opens the perspective of bicolour imaging with a better than shot-noise phase uncertainty by working in the vicinity of the WP. Our results transfer quantum imaging distillation in a noisy environment to the high-gain regime with the ultimate goal of harnessing its full potential by combining bicolour imaging and phase supersensitivity.
Reflectionless pseudospin-1 Dirac systems via Darboux transformation and flat band solutions
Authors: Jakubský V , Zelaya K
Published: January 2024

This manuscript explores the Darboux transformation employed in the construction of exactly solvable models for pseudospin-one particles described by the Dirac-type equation. We focus on the settings where a flat band of zero energy is present in the spectrum of the initial system. Using the flat band state as one of the seed solutions substantially improves the applicability of the Darboux transformation, for it becomes necessary to ensure the Hermiticy of the new Hamiltonians. This is illustrated explicitly in four examples, where we show that the new Hamiltonians can describe quasi-particles in Lieb lattice with inhomogeneous hopping amplitudes.
Automatic transformation of polarization state of light in void medium
Authors: Yang Jianhe , Tao Shaohua
Published: January 2024

Customized polarization state of light plays a pivotal role in numerous scientific domains. Under normal circumstances, light always maintains its polarization state during transmission in void medium or the free space. However, in this work, we have observed that the polarization state of a light beam can be automatically transformed during the propagation without involving a waveplate or scattering of air. The beam changes polarization states at different distances in the free space propagation. Moreover, while polarization states can be preset at different distances, the intensity and phase of the light beam can also be independently designed. The mechanism behind this phenomenon is due to the superposition and diffraction of the controlled light beams. The phenomenon paves the way for applications of constructing key devices, e.g. optical isolator, and offers a broader range of possibilities for applications such as tunable structured devices, optical diodes, and so on.
An effective hydrodynamic description of marching locusts
Authors: Gorbonos Dan , Oberhauser Felix B , Costello Luke L , Günzel Yannick , Couzin-Fuchs Einat , Koger Benjamin , Couzin Iain D
Published: January 2024

A fundamental question in complex systems is how to relate interactions between individual components (‘microscopic description’) to the global properties of the system (‘macroscopic description’). Furthermore, it is unclear whether such a macroscopic description exists and if such a description can capture large-scale properties. Here, we address the validity of a macroscopic description of a complex biological system using the collective motion of desert locusts as a canonical example. One of the world’s most devastating insect plagues begins when flightless juvenile locusts form ‘marching bands’. These bands display remarkable coordinated motion, moving through semiarid habitats in search of food. We investigated how well macroscopic physical models can describe the flow of locusts within a band. For this, we filmed locusts within marching bands during an outbreak in Kenya and automatically tracked all individuals passing through the camera frame. We first analyzed the spatial topology of nearest neighbors and found individuals to be isotropically distributed. Despite this apparent randomness, a local order was observed in regions of high density in the radial distribution function, akin to an ordered fluid. Furthermore, reconstructing individual locust trajectories revealed a highly aligned movement, consistent with the one-dimensional version of the Toner-Tu equations, a generalization of the Navier–Stokes equations for fluids, used to describe the equivalent macroscopic fluid properties of active particles. Using this effective Toner–Tu equation, which relates the gradient of the pressure to the acceleration, we show that the effective ‘pressure’ of locusts increases as a linear function of density in segments with the highest polarization (for which the one-dimensional approximation is most appropriate). Our study thus demonstrates an effective hydrodynamic description of flow dynamics in plague locust swarms.