bluuebunny/crossref_metadata_2025 huggingface dataset:
The research on freezing performance in the cap-type stringers of composite fuselage
Authors: Song Mingliang , Li Lei , Zhou Zhao , Zhu Chuangfeng
Published: August 2024

Composite materials are increasingly used in civil aircraft, where there is water accumulation in the lower panel for special reasons, some of which can enter the interior of the cap-type stringers. The accumulated water inside the stringer undergoes a change of liquid-solid–liquid on each flight, and the thermal expansion and cold contraction caused by ice can have a stripping effect on the co-bonded interface of the stringer to the skin, which potentially causes delamination of the co-bonded interface of the stringer to skin and affects the flight safety. In this paper, the cap-type stringer structure of a common composite fuselage is used as an example to study the reciprocating change process of water in the stringer from liquid to solid. When the total number of cycles exceeds one time the flight life of 34000 cycles, there is some problem with whether the co-bonded interface of the stringer to skin exists the phenomenon of debonding. Due to physical freezing, melting, and the longer test cycle, establishing a similar finite element model is considered after completing appropriate physical tests. The physical change process is usually translated into the mechanical loading test to accelerate the test schedule. The test results showed that the loads from the thermal expansion and cold contraction caused by ice were very small, which caused no delamination of the stringer and the skin and had no effect on flight safety.
Experimental investigation on buffet load characteristics of a wide-body aircraft horizontal-tail in take-off configuration
Authors: Chen Zhenyu , Zhang Lingfeng , Liu Yang
Published: August 2024

Surface buffet load characteristics and structural response characteristics of the horizontal tail were measured and analyzed by installing a subminiature pulsating pressure sensor and root strain gauge on the horizontal tail surface of a rigid full model of a civil wide-body aircraft. The results show that, before buffeting onset, the vibration response of the horizontal tail structure is only affected by the incoming pulsating pressure, and the response frequency is near the natural frequency of the structure. The buffeting coefficient of the structure has a linear relationship with the incoming flow excitation. After buffeting onset, the buffeting load will propagate further along the chord direction of the horizontal tail, and the frequency range will also expand significantly, distributed in the wide frequency range of 20 Hz~1, 000 Hz and maintained at larger incidences.
Wireless passive condition monitoring system for aircraft
Authors: Luo Yuxiang , Cheng Xianfu , Zhang Qiang , Liu Tao , Yu Zhe , Zhu Qixing
Published: August 2024

In response to the risk of settling in the long-term storage of viscoelastic fuel in aircraft solid engines, this study proposes a fuel-settling monitoring system based on the cooperation of implanted optical fibers and wireless passive sensors for the first time. The system does not require wiring holes in the original structure of the engine, avoiding unpredictable damage to the structure. At the same time, the elastic modulus of the settlement monitoring sensor is similar to that of solid fuel, overcoming the problem of measurement uncertainty caused by the mismatch of elastic modulus in traditional sensors. The optical fiber grating sensor arrays are used to calibrate the wireless passive sensor array so that the wireless passive sensors have accurate strain monitoring ability. In the paper, the strain sensitivity coefficient of the wireless passive sensor is up to 230.4 Hz/με, which is important for accurate monitoring of settlement. The fuel settlement is obtained based on the deformation inversion model and more quantitative studies will follow. Finally, the long-term accurate monitoring of the fuel settlement in the confined space is realized.
Experimental study on cloud parameters in an open icing wind tunnel for aircraft ground icing tests
Authors: Zhou Qiongyao , Dong Mingsai
Published: August 2024

Supporting ground icing test of aircraft air intake system, this article uses a seasonal open icing wind tunnel to provide an artificial freezing fog environment. In order to verify that the freezing fog environment created by the seasonal open icing wind tunnel meets the test requirements, the impact of compressed air-water pressure ratio on MVD and the impact of water supply flow rate on LWC were studied in this article. Additionally, an ice thickness evaluation method based on an ice grid to test the uniformity of LWC within a range of 1 m×1 m was conducted. The research results show that: 1) When the compressed-water pressure ratio is 2.6±0.26 (M±SD), the MVD meets the test requirements; 2) LWC and water supply flow rate have a good linear relationship, and LWC increases linearly with the increase of water supply flow rate; 3) The uniformity of LWC within a range of 1 m×1 m can meet the requirements of ±20%, and the consistency between the two tests is good.
Measurement method of vacuum degree in satellite in vacuum thermal test of spacecraft based on diaphragm gauge
Authors: Wu Yue , Xue Cuiping , Xu Zhongxu , Wei Xi , Tao Dongxing
Published: August 2024

The vacuum degree near some instruments and equipment on the monitor is required in the vacuum thermal test of the spacecraft. Only when the vacuum degree meets the requirements, the equipment can be started up. This paper studies the new requirements of the thermal test of the spacecraft, analyzes the reasons why the conventional diaphragm gauge cannot work in a vacuum thermal environment, and designs a new diaphragm gauge. After testing and calibration, it is proved that it can be applied to the measurement of the vacuum degree in the satellite, so as to ensure that the instruments and equipment on the spacecraft can start up normally during the vacuum thermal test and accept the assessment. It effectively guarantees the smooth progress of the thermal test of the spacecraft.
Springback research of tubular structure under lateral compression using explicit and implicit FEA method
Authors: Zhang Ziqian , Zheng Chengyuan , Liu Jianzhi , Zhong Ying
Published: August 2024

The springback of laterally compressed thin-walled tubes is an important issue, which affects the prediction of tubular structure energy absorbing ability and the final sectional profile. So, the springback of laterally compressed tubes after plastic compression should be predicted and calculated in the process of the tube design. However, predicting the springback with traditional theoretical or experimental methods is hard. In the present paper, an explicit and implicit sequence-solving method based on ANSYS/LS-DYNA was developed for calculating and analyzing the springback of the tube under lateral compression by the code ANSYS LS-DYNA. The result implied that the explicit and implicit sequence-solving method is reasonable, and the values of the tube’s springback after lateral compression can be predicted by this FEA method.
Development of a small-sized mobile aerostat system
Authors: Wang Weixin , Wan Xiaogang
Published: August 2024

With the advantages of wide coverage, long endurance, rapid response, and high cost-effectiveness, tethered aerostats have become an attractive elevated platform to carry payloads to conduct surveillance and communication tasks in natural disaster rescue, crowd management, key assets protection, and border surveillance. The paper presents the development of a fast-response ellipsoidal aerostat system (FREAS) for surveillance and communication applications. Requirements for technical parameters, design and engineering, and field tests of the FREAS are described. The field tests show that video surveillance and relay communication performances fully meet expectations for the development. Future work to further verify and improve the aerostat system is finally addressed.
Composite waveform air supply method for air conditioning to improve aircraft cabin air quality
Authors: Cheng Haoyu , Lin Jiaquan , Gao Mei
Published: August 2024

To enhance the air quality in aircraft cabins during the waiting phase on the apron, a composite waveform signal aircraft cabin air supply which combined constant value signal with sinusoidal signal was proposed. In this study, a CFD technology was used to establish a Boeing 737 cabin model. Using NO2 as the bleed pollutant, the airflow characteristics within the cabin model were simulated when cabin air conditioning used constant value signal air supply, sinusoidal signal air supply, and composite waveform signal air supply. The evaluation of different air supplies was based on indicators such as the rate of mass fraction descent ROD, Draft Rating DR, and TAPPD. Additionally, a total efficiency coefficient function G(X) was constructed using the efficacy coefficient method. When the composite waveform signal was used for cabin air conditioning, the G(X) value was a 22.4% increase compared with using constant value signal air supply and a 5% increase compared with using sinusoidal signal air supply. These findings indicate that cabin air conditioning uses composite waveform signal air supply, and the air quality in the aircraft cabin is optimal.
A study on the method of obtaining field dynamic characteristic parameters of a rocket sled
Authors: Zheng Zhuowen , Shang Fei
Published: August 2024

In order to solve the problem of obtaining the accuracy of dynamic characteristic parameters in a rocket sled test, a multi-channel parallel storage test device for a rocket sled field test was designed and verified in the laboratory. With STM32 as the control core and NAND FLASH as the data memory, the multi-channel vibration, shock, and course acceleration signals can be collected, stored, and transmitted synchronously. Through laboratory verification, the performance test results of the system show that the system can complete the multi-channel 500 kHz sampling frequency parameter acquisition and storage, and can realize the normal acquisition of vibration, shock, and course acceleration signals under the environment of high-speed movement of a rocket sled.
Shock attenuation efficiency of different buffer materials during the separation of explosive bolts
Authors: Zhang Junjian , Gong Linhui , Gao Lijun , Liao Guoliang , Zeng Qinglei
Published: August 2024

Explosive bolts are widely used in spacecraft separation. Strong transient shock waves are usually generated during the unlocking process, which can influence the precision of the instruments inside the spacecraft. Therefore, reducing the shock generated during the explosive bolt-unlocking process is important in space engineering. This paper establishes a simplified numerical model for the explosive bolt separation process to investigate the shock attenuation efficiency of different buffer materials, including fluoroplastics, rubbers, and aluminum foams. The simulation results show that rubbers with a medium modulus can provide effective shock attenuation. For specific impact conditions, it is necessary to select aluminum foams with moderate platform stress to absorb the impact energy. If the platform stress is too low, it may result in an inadequate energy absorption capacity. In contrast, excessively high platform stress may limit plastic deformation, hindering the full utilization of energy absorption capabilities.
Design and experiment of a vertical fixed-wing UAV based on electric culver
Authors: Wu Wenqi , Ren Mengyuan , Long Yaosong
Published: August 2024

In recent years, drones have played an important role in warfare. In response to the issues of high noise, slow flight speed, and poor maneuverability of traditional rotary-wing vertical take-off and landing UAVs, as well as the complexities and high energy consumption of traditional tilt-rotor structures, a novel fixed-wing UAV with electrically controlled thrust vectoring based on the ducted fan concept was designed. Firstly, the selection and analysis of the wing landing gear were carried out. Secondly, the mechanism analysis and strength verification were conducted for the designed thrust vectoring three-axis rotating nozzle. Finally, a servo control method was proposed, and a prototype was manufactured for flight testing. The results validated that compared to similar power-level rotary-wing vertical take-off UAVs, the speed of this UAV increased by 43.2%, and the maneuvering radius improved by 56.79%.
Simulation of coaxial electrostatic atomization of nanofluids
Authors: Liu Jinyu , Su Yu , You Jiaxi
Published: August 2024

The microscopic characteristics of the coaxial electrostatic atomization of nanofluids have a very important impact on the field of cooling and lubrication. In this paper, a finite element model of coaxial electrostatic atomization of nanofluids is established by using the ternary phase field method in the voltage range of stable cone jets, and different outer and inner fluids are simulated to compare the influence of different inner and outer fluid types on the formation of cone jets and the broken droplets at the end of the coaxial electrostatic atomization of nanofluids. The results show that the formation of the coaxial conical jet is faster when the outer fluid is castor oil and its nanofluids. When the external fluid is sunflower oil and its nanofluids, the charge concentration volume force is higher than the outer fluid for castor oil and its nanofluids.
Simulation of the formation process of nanofluid electrostatic atomization under different voltages
Authors: Liu Pan , Su Yu , Liu Jinyu
Published: August 2024

Voltage has an impact on the electrostatic atomization effect of nanofluids. In this study, by using COMSOL software, a simulation model of electrostatic atomization of graphite water-based nanofluids under different voltages was established. The process of cone jet formation under different voltages was observed through three-dimensional visualization of volume fraction maps. The formation processes of graphite water-based nanofluid cone jets were analyzed from three aspects: electric field force, charge concentration, and volume force. The results indicate that the droplet formation speed increases with higher voltage. Under −10 kV, graphite water-based nanofluids exhibit faster cone jet formation, thorough breakup of droplets at the jet’s tip, and better atomization effects.
Research on the application of boiling heat transfer in microchannels of high power electronic chips
Authors: Wang Yalong , Zhang Yun , Zhou Dongliang , Liu Tao , Liu Fan , Tao Cheng , Yu Xingang , Miao Jianyin
Published: August 2024

For electronic devices with single chip heat consumption exceeding 600 W and heat flux density exceeding 50 W/cm2, the heat dissipation requirement of a single cabinet exceeding 50 kW provides a new solution for high heat consumption and high heat flux chip heat dissipation by combining boiling heat transfer with microchannels. The flow and heat transfer differences between microchannel and conventional channel evaporators were verified through experiments. The results show that compared with conventional channels, the heat dissipation temperature difference of microchannels is reduced by 44%. The slender structure of microchannel evaporators can achieve better heat transfer performance, and the flow boiling heat transfer coefficient can reach 2-3 W/cm2·K.
Study on passivation effect of dissolved hydrogen on primary material
Authors: Ai B , Liu C S , Lin G X , Sun Y , Tian Z H
Published: August 2024

In this project, 304L stainless steel, the key material of the boron-free primary circuit system, was selected as the research object, and three passivation process conditions were simulated by high temperature and high pressure circulation loop to study the influence of hydrogenation on the thermal passivation effect. Scanning electron microscope, transmission electron microscope and corrosion weight test were used to study the influence of dissolved hydrogen on the morphology, composition, film thickness and corrosion rate of the oxide film of the primary circuit material. The results show that: (1) the 304L stainless steel has a double-layer oxide film pore structure under the three passivation process conditions, and the corrosion rate is at a low level, and the corrosion rate decreases to a certain extent under the hydrogenation condition; (2) After hydrogenation, the thickness of the oxide film formed on the surface of 304L stainless steel becomes thinner and the surface oxygen content decreases, which may be related to the reducibility formed by hydrogenation.
Molecular Simulation Study on Corrosion Inhibition Mechanism of Ce Modified Carbon Point Corrosion Inhibitor for Carbon Steel
Authors: Li Fengting , Zhou Yi , Qu Wentao , Wang Zhikun , Hu Songqing
Published: August 2024

The molecular activity of Ce-doped carbon dots and their adsorption behavior on metal surface were studied by quantitative and kinetic calculation methods. It is found that Ce doping will become the reactive center of molecules, and the carbon point reaction activity is stronger after Ce atom doping. Carbon dots doped with Ce are more likely to be adsorbed on the surface of Fe. Due to the doping of Ce atoms, the nucleophilic and electrophilic activities of carbon sites have been enhanced, so the overall activity of molecules has been improved. The carbon point doped with Ce can more easily agree with the displacement of water molecules, thus achieving better protection effect. The performance of CeCD doped with monoatomic form will be slightly better than that of CeCDTC doped with CeO cluster form.
Evaluation of casing corrosion in different well sections and application of anti-corrosion schemes for shale gas wells in the southern Sichuan basin
Authors: Xu K W , Wang Y , Zhou L , Duan Y
Published: August 2024

The frequent occurrence of wellbore corrosion in shale gas development blocks within the southern Sichuan basin has led not only to the failure of well integrity but also severely restricted the safe and efficient development of shale gas resources. To address the challenge of well integrity failure caused by corrosion in shale gas wells, indoor experiments were conducted. These experiments were based on the typical service conditions of shale gas wells in two major blocks, C and L, located in the southern Sichuan basin. The aim was to evaluate the corrosion status of the entire well casing and analyze the underlying corrosion mechanisms. On this basis, a comparison was made including the corrosion resistance performance and the 20-year service feasibility of various anti-corrosion technologies. Based on the results, a casing anti-corrosion scheme was selected and subsequently applied in two field wells.Research has shown that the upper and middle sections of the casing predominantly experience CO2 and microbial synergistic corrosion, while the lower section is mainly subject to CO2 corrosion. As the temperature increases, the synergistic effect of CO2 and microorganisms on corrosion diminishes. This results in more severe localized corrosion in the upper section of the casing compare to the middle section. When the temperature reaches the service condition typical for the lower section of the casing, CO2 corrosion accelerates, leading to both localized and uniform corrosion falling within the extremely severe corrosion range. The uniform corrosion resistance of the antibacterial casing deteriorates with increasing temperature, although their resistance to localized corrosion remains good. Chemical anti-corrosion methods can significantly reduce the uniform and localized corrosion of the upper and middle sections of the casing, but high attention should be paid to the adaptability of the chemical under high temperatures. For a 20-year service life, two anti-corrosion schemes suitable for different shale gas blocks have been proposed. The research results can provide technical support for anti-corrosion to ensure the integrity of shale gas wells in the southern Sichuan basin.
Dissolution behavior of steam generator deposit in oxalic acid
Authors: Yan Xiao , Lijun Song , Canshuai Liu , Zhaohui Tian , Yun Sun
Published: August 2024

The dissolution behavior of simulated deposit Fe3O4 and steam generator sludge in oxalic acid solution was studied by methods of SEM, XRD, XRF and ICP-OES. The electrochemical properties of simulated deposit chemically modified electrodes in oxalic acid solution were tested under a three-electrode system to guide the optimization of chemical cleaning process. The results indicate that oxalic acid chemical cleaning agent could effectively remove iron oxidation deposits and harmful elements such as Cu, Pb and Al in SG sludge. With the increase of oxalic acid concentration, the solubility of the simulated deposit is enhanced. But when the oxalic acid concentration reached 5%, the dissolution process of SG sludge will change into the deposition process after reaching a brief equilibrium, and FeC2O4(H2O)2 crystals will be formed. The solubility of simulated deposit in the oxalic acid is stronger than that of the sludge, which is related to the particle size difference between the simulated deposit and the SG sludge, as well as the influence of Cr, Mn, Ti, Ni, Mg and other elements doped in the oxide lattice of the sludge. The electrochemical reaction process of simulated deposit chemically modified electrode in oxalic acid solution is adsorption controlled.
Fabrication of porous carbon nanofibers by electrospinning as free-standing anodes for lithium-ion batteries
Authors: Manh Le Dang , Nguyen Tuan Loi , Nguyen Minh Thu , Tran Van Man , Pham Hoai Phuong , Ngo Hai Dang , Thi Thu Nguyen Thuy , Bui Trung Hieu
Published: August 2024

Free-standing anodes composed of porous carbon nanofibers (PCNFs) were fabricated by electrospinning for use in lithium-ion batteries. The use of terephthalic acid (PTA) as the sublimating agent, one-step carbonization at 900 °C for 2 h under vacuum converts the as-prepared samples to have interconnected pores along the PCNFs interior with numerous surface openings. The electrode was characterized using scanning electron microscopy (SEM), surface area analysis (BET), x-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR), and Raman spectra (Raman). This strategy makes the PCNFs with a specific surface area of up to 290 m2 g−1, which is significantly higher than the CNFs with 107 m2 g−1. As a result, electrochemical tests exhibited that the PCNFs have a high discharge capacity of 750 mAh g−1, which is sharply higher than that of the CNFs (234 mAh g−1) at 100 mA g−1. Even at a current density of 3000 mA g−1, the PCNFs still exhibit a very high discharge capacity of 621 mAh g−1. The present study may provide an effective strategy for synthesizing low-cost, binder-free, and environmentally friendly anodes for lithium-ion batteries with outstanding properties.
Selective and reversible carbon mono oxide gas detection using silver doped octahedral molecular sieves (OMS-2) nanorods
Authors: Gupta Amit Kumar , Singh Priyanshu , Jaiswal Monica , Mittal Jagjiwan , Aravindan Sivanandam , Chaudhary Sumit , Sharma Satinder Kumar , Kumar Robin
Published: August 2024

In this work a potable, resistive sensor is fabricated for the selective detection of CO gas using nanorods of Ag doped octahedral molecular sieves-2 (Ag-OMS-2). During exposure to carbon monoxide (CO) gas at room temperature, resistance of Ag-OMS-2 film was dropped from 557 kΩ to 352 kΩ in just 18 sec. However, exposed sample regained its initial resistance value in 25 sec when CO gas source was removed. Both sensing and recovery processes were carried out at room temperature. The sensor film showed excellent reproducibility during several cycles of CO gas exposure. Swift activation of oxygen molecules for the oxidation of CO by the silver present in the tunnel of manganese oxide network is supposed to be responsible for sensing activity of Ag-OMS-2 towards carbon monoxide gas.
FcRider: a recombinant Fc nanoparticle with endogenous adjuvant activities for hybrid immunization
Authors: Mao Changchuin , Eberle Karen , Chen Xiaojie , Zhou Yiming , Li Jun , Xin Hong , Gao Wenda
Published: August 2024

Active immunization (vaccination) induces long-lasting immunity with memory, which takes weeks to months to develop. Passive immunization (transfer of neutralizing antibodies) provides immediate protection, yet with high cost and effects being comparatively short-lived. No currently approved adjuvants are compatible with formulations to combine active and passive immunizations, not to mention their huge disparities in administration routes and dosage. To solve this, we engineered the Fc fragment of human IgG1 into a hexamer nanoparticle and expressed its afucosylated form in Fut8−/− CHO cells, naming it “FcRider.” FcRider is highly soluble with long-term stability, easily produced at high levels equivalent to those of therapeutic antibodies, and is amenable to conventional antibody purification schemes. Most importantly, FcRider possesses endogenous adjuvant activities. Using SWHEL B cell receptor (BCR) transgenic mice, we found that HEL-FcRider induced GL7+ germinal center B cells and HEL-specific IgG. Similarly, immunizing mice with UFO-BG-FcRider, a fusion containing the stabilized human immunodeficiency virus-1 (HIV-1) Env protein as immunogen, promoted somatic hypermutation and generation of long CDR3 of the IgG heavy chains. Intramuscular injection of (Fba + Met6)3-FcRider, a fusion with two peptide epitopes from Candida albicans cell surface, stimulated strong antigen-specific IgG titers. In three different models, we showed that afucosylated FcRider functions as a multivalent immunogen displayer and stimulates antigen-specific B cells without any exogenous adjuvant. As an antibody derivative, afucosylated FcRider could be a novel platform combining vaccines and therapeutic antibodies, integrating active and passive immunizations into single-modality “hybrid immunization” to provide complete and long-lasting protection against infections, and may open new avenues in cancer immunotherapy as well.
Ending civil wars
Authors: Toft Monica Duffy
Published: August 2024

Just as no two wars are alike, none of their endings are exactly the same either. But broadly speaking, the main options are via a stalemate or ceasefire, a negotiated settlement, or with victory, either by the government or the rebel group. A stalemate or a ceasefire involve all sides laying down their arms and no agreement on the future make up the government. Negotiated settlements more often involve both sides laying down their arms and a shared agreement on and participation in a new government. Victories by either side are more intuitive—one side defeats the other thereby empowering the winning side to determine the future of the government and country. But, which type is the most likely and which leads to stability and peace? The answers to these questions are complicated.
A review: simulation tools for genome-wide interaction studies
Authors: Shang Junliang , Xu Anqi , Bi Mingyuan , Zhang Yuanyuan , Li Feng , Liu Jin-Xing
Published: August 2024

Genome-wide association study (GWAS) is essential for investigating the genetic basis of complex diseases; nevertheless, it usually ignores the interaction of multiple single nucleotide polymorphisms (SNPs). Genome-wide interaction studies provide crucial means for exploring complex genetic interactions that GWAS may miss. Although many interaction methods have been proposed, challenges still persist, including the lack of epistasis models and the inconsistency of benchmark datasets. SNP data simulation is a pivotal intermediary between interaction methods and real applications. Therefore, it is important to obtain epistasis models and benchmark datasets by simulation tools, which is helpful for further improving interaction methods. At present, many simulation tools have been widely employed in the field of population genetics. According to their basic principles, these existing tools can be divided into four categories: coalescent simulation, forward-time simulation, resampling simulation, and other simulation frameworks. In this paper, their basic principles and representative simulation tools are compared and analyzed in detail. Additionally, this paper provides a discussion and summary of the advantages and disadvantages of these frameworks and tools, offering technical insights for the design of new methods, and serving as valuable reference tools for researchers to comprehensively understand GWAS and genome-wide interaction studies.
Emergency department referrals for CT imaging of extremity soft tissue infection: before and during the COVID-19 pandemic
Authors: Nanapragasam Andrew , White Lawrence M
Published: August 2024

Objectives

To evaluate the incidence and spectrum of findings in patients referred for CT imaging of extremity soft tissue infection in the adult emergency department (ED) setting before and during the COVID-19 pandemic.

Methods

Two hundred thirteen CT exams in the pre-COVID cohort (February 1, 2018-January 31, 2020) and 383 CT exams in the COVID cohort (February 1, 2020-January 31, 2022) were evaluated in this multicentre, retrospective study. Demographic information and clinical histories were collected, along with regional data on COVID-19 hospitalizations and deaths.

Results

Comparable age and sex distribution was found in the pre-COVID (average age of 53.5 years; male: female ratio of 71:29) and COVID (average age of 54.6 years; male: female ratio of 69:31) cohorts. The frequency of reported clinical risk factors (diabetes mellitus, injected drug use, prior surgery, animal bite) was not significantly different between the two cohorts. Findings of simultaneous involvement of both superficial and deep soft tissue infection on CT imaging were significantly higher in the COVID cohort (53.4%) than in the pre-COVID cohort (33.7%). CT findings of phlegmon (49.1% vs 22.1%), ulcers (48.8% vs 30%), osteomyelitis (21.7% vs 13.1%), as well as localized (18.8% vs 11.7%) and extensive (3.7% vs 2.3%) soft tissue gas were significantly more common in the COVID cohort than in the pre-COVID cohort.

Conclusions

During the COVID-19 pandemic, the number of ED CT exams for the evaluation of extremity soft tissue infection increased, with this imaging also showing more advanced disease. Pandemic-related modifications to human behaviour and re-distribution of healthcare resources may underlie these observed changes.

Advances in knowledge

This multi-centre study shows an increase in extremity soft tissue infection presenting to the ED during the pandemic. This finding is important for future pandemic preparations, as it can aid in the decision-making process around resource allocation.
Complex abdominal aortic aneurysms: a review of radiological and clinical assessment, endovascular interventions, and current evidence of management outcomes
Authors: Agarwal Girija , Hamady Mohamad
Published: August 2024

Endovascular aortic aneurysm repair (EVAR) is an established approach to treating abdominal aortic aneurysms, however, challenges arise when the aneurysm involves visceral branches with insufficient normal segment of the aorta to provide aneurysm seal without excluding those vessels. To overcome this, a range of technological developments and solutions have been proposed including fenestrated, branched, physician-modified stents, and chimney techniques. Understanding the currently available evidence for each option is essential to select the most suitable procedure for each patient. Overall, the evidence for fenestrated endovascular repair is the most comprehensive of these techniques and shows an early post-operative advantage over open surgical repair (OSR) but with a catch-up mortality in the mid-term period. In this review, we will describe these endovascular options, pre- and post-procedure radiological assessment and current evidence of outcomes.
Contemporary treatment options in heart failure with preserved ejection fraction
Authors: Peikert Alexander , Solomon Scott D
Published: August 2024

Heart failure with preserved ejection fraction (HFpEF) constitutes approximately half of the heart failure population, with its prevalence markedly increasing with older age and the presence of cardio-metabolic comorbidities. Although HFpEF is associated with a high symptom- and mortality burden, historically there have been few evidence-based treatment options for patients with HFpEF. Recent randomized clinical trials have expanded evidence on pharmacological treatment options, introducing new agents for managing HFpEF. Given the complex clinical phenotype with pathophysiological heterogeneity and evolving diagnostic standards, the evidence-based management of HFpEF remains challenging for clinicians. This review summarizes the latest evidence from contemporary randomized clinical trials and recent guideline recommendations to provide guidance for the treatment of patients with HFpEF.
Fulminant eosinophilic myocarditis and refractory ventricular arrhythmias requiring mechanical circulatory support: a case report
Authors: Brick Claudia , Leet Angeline , Tay Hui , Kaye David M , Taylor Andrew J
Published: August 2024

Background

Fulminant eosinophilic myocarditis (EM) is a rare and often fatal condition that may present atypically and be complicated by ventricular arrhythmias. Treatment involves high-dose corticosteroids to suppress eosinophilia, as well as increasing use of mepolizumab, an anti-interleukin-5 antibody with evidence for long-term efficacy and safety.

Case summary

A 38-year-old woman presented to the emergency department with neck pain and fatigue, and after extensive investigation was diagnosed with EM secondary to idiopathic hypereosinophilic syndrome. The patient was treated with methylprednisolone for eosinophil suppression and warfarin due to the presence of biventricular apical thrombi. Despite previously stable haemodynamics, the patient had a cardiac arrest due to ventricular fibrillation on Day 11 of hospitalization, requiring 30 min of cardiopulmonary resuscitation and commencement of veno-arterial extracorporeal membrane oxygenation support due to refractory ventricular arrhythmias. The patient was urgently listed for heart transplant but a suitable match was not identified, and she was weaned to pharmacologic support on Day 34. The patient survived with minimal sequelae and has returned to full-time work. She remains on mepolizumab as a steroid-sparing agent, therapeutic anti-coagulation, and heart failure therapy.

Discussion

This report describes an atypical presentation of fulminant EM requiring weeks of mechanical circulatory support due to refractory arrhythmia rather than heart failure. The case also highlighted the benefits of non-invasive cardiac magnetic resonance imaging in both diagnosis and prognostication of EM, as well as the need to maintain a high index of suspicion for this rare disease.
Acute myocardial infarction caused by vasospasm of a jailed diagonal branch subsequent to stent implantation in the left anterior descending artery: a case report
Authors: Yoshikawa Hiroshi , Sugiyama Tomoyo , Araki Makoto , Yonetsu Taishi , Sasano Tetsuo
Published: August 2024

Background

Coronary stents have been reported to cause endothelial dysfunction, potentially leading to spasm at the edges of the stent. However, the clinical significance of vascular spasm in stent-jailed side branches remains poorly understood.

Case summary

A 67-year-old woman was referred to our hospital for angina occurring both during exercise and at rest. An everolimus-eluting stent was implanted for a physiologically significant stenosis in the proximal left anterior descending artery, while an intermediate stenosis persisted in the jailed first diagonal branch. Although her exertional angina resolved, her rest symptoms worsened after percutaneous coronary intervention (PCI). She was admitted with acute myocardial infarction 1 month later. Urgent coronary angiography showed no stent failure, but an acetylcholine provocation test induced a spasm leading to total occlusion of the jailed diagonal branch. An additional stent was implanted in the diagonal branch due to a residual stenosis even after isosorbide dinitrate administration. After the second PCI, her chest pain completely resolved.

Discussion

This is the first documentation of aggregated coronary spasm observed at the ostium of stent-jailed side branch. Stent implantation may induce endothelial dysfunction and promote inflammation, leading to spasms particularly at stent edges. This phenomenon can extend to side branches jailed by the stent, and invasive intervention may be a viable therapeutic strategy for such cases.
Elevated C-Reactive Protein in Older Men With Chronic Pain: Association With Plasma Amyloid Levels and Hippocampal Volume
Authors: Bell Tyler R , Franz Carol E , Thomas Kelsey R , Williams McKenna E , Eyler Lisa T , Lerman Imanuel , Fennema-Notestine Christine , Puckett Olivia K , Dorros Stephen M , Panizzon Matthew S , Pearce Rahul C , Hagler Donald J , Lyons Michael J , Elman Jeremy A , Kremen William S
Published: August 2024

Background

Chronic pain leads to tau accumulation and hippocampal atrophy, which may be moderated through inflammation. In older men, we examined associations of chronic pain with Alzheimer’s disease (AD)-related plasma biomarkers and hippocampal volume as moderated by systemic inflammation.

Methods

Participants were men without dementia. Chronic pain was defined as moderate-to-severe pain in 2+ study waves at average ages 56, 62, and 68. At age 68, we measured plasma amyloid-beta (Aβ42, n = 871), Aβ40 (n = 887), total tau (t-tau, n = 841), and neurofilament light chain (NfL, n = 915), and serum high-sensitivity C-reactive protein (hs-CRP, n = 968), a marker of systemic inflammation. A subgroup underwent structural MRI to measure hippocampal volume (n = 385). Analyses adjusted for medical morbidities, depressive symptoms, and opioid use.

Results

Chronic pain was related to higher Aβ40 (β = 0.25, p = .009), but hs-CRP was unrelated to AD-related biomarkers (ps > .05). There was a significant interaction such that older men with both chronic pain and higher levels of hs-CRP had higher levels of Aβ42 (β = 0.36, p = .001) and Aβ40 (β = 0.29, p = .003). Chronic pain and hs-CRP did not interact to predict levels of Aβ42/Aβ40, t-tau, or NfL. Furthermore, there were significant interactions such that Aβ42 and Aβ40 were associated with lower hippocampal volume, particularly when levels of hs-CRP were elevated (hs-CRP × Aβ42: β = −0.19, p = .002; hs-CRP × Aβ40: β = −0.21, p = .001), regardless of chronic pain status.

Conclusions

Chronic pain was associated with higher plasma Aβ, especially when hs-CRP was also elevated. Higher hs-CRP and Aβ levels were both related to smaller hippocampal volumes. Chronic pain, when accompanied by systemic inflammation, may elevate the risk of neurodegeneration in AD-vulnerable regions.
In Their Words: African American and Latine Immigrant Older Adults (Re)Define Civic Participation
Authors: Reyes Laurent
Published: August 2024

Objectives

Older adults’ civic participation has received considerable attention. However, this literature has understudied the experiences of civic participation among minoritized ethnoracial older adults. Particularly absent from this literature is the contextualization of civic participation as it exists within cultural and historical structures of inequality that influence how these populations understand, participate, and experience civic life.

Methods

A phenomenological design was used to explore civic participation through participants’ experiences and unique perspectives. Thirty-four in-depth, semistructured interviews were conducted with Latine immigrant and Black older adults (ages 60+) living in New Jersey and New York City. A conceptual content analysis was used to identify how older Black and Latine immigrant adults define civic participation for themselves.

Results

This study presents 3 new definitions of civic participation, that are derived directly from participants’ conceptualization and applied across the lived experiences. Definitions present civic participation as the responsibility of community belonging; as a religious/spiritual practice; and as a way of life. These definitions provide new perspectives by which to study civic participation and challenge current framing of helper and needy, altruism, the voluntary nature of participation, and the separation between social, political, and spiritual participation.

Discussion

Findings from this study contribute to expanding gerontology’s ontological imagination of how civic participation is experienced and conceptualized among older Latine immigrants and Black adults. The expertise shared by older African Americans and Latine immigrants lends us important perspectives to develop a critical theoretical framework by which scholars can more accurately study civic participation among this diverse population.
Quantifying projected changes in evaporation and solar irradiation for Iraq in the 21st century using representative concentration pathways
Authors: Ghanim Marrwa S , Sultan Maitham A , Hashim Bassim Mohammed , Sultan Aljibori Hakim S , Hammadi Alaa M , Mahdi Jasim M
Published: August 2024

Iraq's dry and semi-arid climate makes it highly vulnerable to climate change impacts including increased solar irradiation, evaporation rates, and water scarcity risks. This study utilizes the CMIP5 climate model projections from CCSM4 under RCP2.6 and RCP8.5 scenarios to analyze the projected changes in annual evaporation and solar irradiation across Iraq over 2020–2100. The analysis is conducted spatially across 18 locations and temporally across four future periods (2020–2040, 2041–2060, 2061–2080, 2081–2100). Under RCP2.6, evaporation rates are estimated to increase by 11–16.3 kg/m2 (+11% to +20%) in northern Iraq and 16.3–20.1 kg/m2 (+16% to +25%) in southern Iraq by 2100. Solar irradiation is projected to rise marginally by 1.8–3.4 W/m2 (+1% to +2%) countrywide, with the highest levels in western Iraq (224.4–252.3 W/m2) and lowest in northern areas (223.5–232.7 W/m2). The projected rising evaporation can significantly exacerbate water scarcity risks, while the limited irradiation increase can impact long-term planning of solar energy investments. The quantified projections highlight risks to Iraq's water and energy security, underscoring the urgent need for adaptation strategies to enhance resilience.
Embodied Computational Evolution: A Model for Investigating Randomness and the Evolution of Morphological Complexity
Authors: Aaron E , Long J H
Published: August 2024

For an integrated understanding of how evolutionary dynamics operate in parallel on multiple levels, computational models can enable investigations that would be otherwise infeasible or impossible. We present one modeling framework, Embodied Computational Evolution (ECE), and employ it to investigate how two types of randomness—genetic and developmental—drive the evolution of morphological complexity. With these two types of randomness implemented as germline mutation and transcription error, with rates varied in an $11\times 11$ factorial experimental design, we tested two related hypotheses: (H1) Randomness in the gene transcription process alters the direct impact of selection on populations; and (H2) Selection on locomotor performance targets morphological complexity. The experiment consisted of 121 conditions; in each condition, nine starting phenotypic populations developed from different randomly generated genomic populations of 60 individuals. Each of the resulting 1089 phenotypic populations evolved over 100 generations, with the autonomous, self-propelled individuals under directional selection for enhanced locomotor performance. As encoded by their genome, individuals had heritable morphological traits, including the numbers of segments, sensors, neurons, and connections between sensors and motorized joints that they activated. An individual’s morphological complexity was measured by three different metrics derived from counts of the body parts. In support of H1, variations in the rate of randomness in the gene transcription process varied the dynamics of selection. In support of H2, the morphological complexity of populations evolved adaptively.
Comprehensive evaluation of cocaine and its hydroxy metabolites in seized cocaine and a large cohort of hair samples
Authors: Madry Milena M , Denifle Teresa , Binz Tina M , Bogdal Christian , Kraemer Thomas , Baumgartner Markus R
Published: August 2024

As cocaine (COC) is not only incorporated into hair via blood following ingestion but also by external contamination, hair samples are commonly tested for COC metabolites to prove ingestion. However, COC metabolites can also be present as degradation products in typical street COC samples. The present study investigates minor hydroxycocaine (OH-COC) metabolites p- and m-OH-COC together with p- and m-hydroxybenzoylecgonine (OH-BE) in seized COC (n = 200) and hair samples from routine case work (n = 2389). Analytical results of hair samples were interpreted using an established decision model for the differentiation between actual use and external contamination using metabolic ratios (metabolite to COC). They were further examined concerning background of request, hair color, body site of sample collection, sex, and metabolic ratios of the main metabolites [benzoylecgonine (BE), norcocaine (NC), and cocaethylene (CE)]. All seized COC samples were positive for p- and m-OH-COC with a maximum percentage of 0.025% and 0.052%, respectively; p- and m-OH-BE were detected in 55% and 56% of samples with a maximum percentage of 0.044% and 0.024%, respectively. Analytical results of 424 hair samples (17.7%) were interpreted as being predominantly from contamination; the majority of these samples were from traffic medicine cases (83.7%). Metabolic ratios of minor OH-COC metabolites were significantly higher in hair samples interpreted as originating from use than in samples interpreted as caused by contamination. Metabolic ratios for OH-COCs were significantly higher in forensic cases compared to abstinence controls and also in black hair compared to blond/gray hair. However, this was not the case for OH-BE metabolic ratios. No statistical difference was observed with regard to the donor’s sex. OH-COC metabolic ratios increased significantly with increasing ratios of NC and CE to COC, respectively. The study demonstrates that OH-COC metabolites (including thresholds for their metabolic ratios) must be used for a reliable interpretation of positive COC results in hair samples.
National Security and FDI Screening in China
Authors: Kokkoris Ioannis
Published: August 2024

The chapter delves into the intricate landscape of non-competition interests in China’s merger control regime, examining the interplay between industrial policy and national security concerns. It explores how these non-competition considerations shape the decision-making process of the Chinese competition authority. Discussing the merger control and distinct characteristics of China’s enforcement practices highlights the pervasive influence of industrial policy. The evolution of China’s industrial policy is analysed, and while MOFCOM has been criticized for aligning with it, the recent codification of the Fair Competition Review System should mitigate this under SAMR’s jurisdiction. The chapter then focuses on the national review, analysing its substantive and procedural facets in-depth. The chapter concludes by underscoring the ever-evolving nature of non-competition interests in China’s merger control landscape. It emphasizes the intricate connection between industrial policy and national security and anticipates an escalation of national security reviews, especially in data-driven activities.