bluuebunny/crossref_metadata_2025 huggingface dataset:
Prediction of Spray Collapse Patterns on Different Fuel Mixture Compositions Based on Deep Learning Framework
Authors: Zhao Fengnian , Meng Yangrui , Zhou Ziming , Hung David L. S.
Published: December 2024

Flash boiling significantly enhances fuel atomization quality but concurrently amplifies the incidence of spray collapse — a phenomenon detrimental to combustion efficiency and emission control. This challenge is particularly pronounced in multi-component fuel sprays, which are integral to optimizing biofuel and alternative fuel applications. Despite advances in data-driven methodologies for categorizing spray collapse conditions into discrete states based on fuel composition and experimental parameters, a critical gap remains in our capability to infer the specific morphology of spray plumes. In order to bridge the gap by quantitatively predicting the cross-pattern spray morphologies, this study utilized the macroscopic spray cross-patterns of multiple-component fuel mixtures under 12 different sets of fuel temperatures captured by a high-speed planar laser Mie-scattering imaging system. A dataset obtained under 12 sets of experimental conditions was employed to train a physics-guided deep learning framework. This framework integrates domain-specific knowledge with deep learning algorithms to accurately model the complex interactions between fuel mixture components and their impact on spray dynamics. The results indicated that the proposed framework could efficiently capture the underlying correlations between varying fuel mixture compositions and their resultant spray patterns given certain environmental parameters. Moreover, it exhibited capacities to extrapolate beyond the discrete experimental dataset, predicting the fuel spray morphology under untested fuel compositions. This predictive capability facilitates the identification of optimal mixture states for achieving superior fuel atomization quality, thereby contributing to the advancement of fuel efficiency and emissions reduction strategies.
Investigating the Combustion Performance of Dual Fuel Combustion With Diesel and Port Injected Hydrogen in a Large Bore Locomotive Engine
Authors: O’Donnell Patrick C. , Wu Sicong , Kazmouz Samuel J. , Klingbeil Adam , Lavertu Thomas , Jayakar Vijayaselvan , Sheth Pushkar , Sapkota Pradeep , Liu Shuaishuai , Wijeyakulasuriya Sameera , Ameen Muhsin
Published: December 2024

The heavy-duty transportation sector has primarily relied on conventional diesel combustion engines given their reliability and high thermal efficiency relative to spark ignition engines, but increased focus on reducing greenhouse gas emissions has led to investigation into alternative fuels. Gaseous hydrogen fuel has garnered a great deal of recent interest in the engine community given it has zero carbon, but hydrogen is not available at the scale and cost that petroleum fuels are currently available, and this is a barrier to adoption for industries that are looking to decarbonize their operations. Because of the fuel flexibility provided, dual fuel technology offers a pathway for some industries to adopt hydrogen as a fuel source while maintaining sufficient flexibility in times and locations where the new fuel is not yet available.

This computational study investigates dual fuel combustion in a large bore locomotive engine architecture using direct injected diesel and port injected gaseous hydrogen fuel. Previous computational work was done with this engine model to obtain an optimal port fuel injection configuration that maximizes hydrogen mass flow into the combustion chamber and minimizes in-cylinder charge stratification [18]. With an optimal port fuel injection configuration, simulations of varying substitution ratio, compression ratio, intake manifold air temperature, diesel injection timing, and diesel injection pressure were performed to understand the effect of each parameter on combustion performance. Results indicated that both increased substitution ratio and higher intake air temperature accelerates hydrogen flame propagation and can result in high peak cylinder pressures and rapid maximum pressure rise rates. It was also seen that a lower compression ratio has the potential to achieve higher substitution ratios at acceptable peak cylinder pressures. Additionally, diesel injection timing and injection pressure were demonstrated as effective methods for controlling dual fuel combustion heat release rates. These simulation results are then discussed in general to understand how to maximize substitution ratio and how direct injection hydrogen could further improve combustion performance.
Lean Limit Extension in Hydrogen Direct Injection Pre-Chamber Opposed-Piston Engines: A Computational Approach
Authors: Menaca Rafael , Shakeel Mohammad Raghib , Moreno-Cabezas Kevin , Vorraro Giovanni , Turner James W. G. , Im Hong G.
Published: December 2024

Opposed-piston 2-stroke (OP2S) engines hold promise for achieving elevated thermal efficiencies stemming from their low surface-to-volume ratio and reduced heat transfer losses. When powered by hydrogen (H2), OP2S engines offer a compelling pathway towards high-efficiency, carbon-neutral powertrains. However, operating these engines at very lean air-to-fuel ratios, while enhancing efficiency, poses challenges to combustion stability. This study aims to investigate the extension of lean limit of H2 using an active pre-chamber (PC) utilizing a small fraction of total fuel provided, in order to enhance the ignition of the ultra-lean bulk mixture by the hot jet injection. A parametric study was conducted by varying the quantity of fuel injected to identify the stable operation limit without misfire. A comparative analysis of PC ignition against spark ignition modes is conducted to demonstrate the superiority of PCs in facilitating ignition and extending lean limit operation.
Computational Analysis of Peripheral Fuel Injection (PeFI) to Enhance Fuel-Oxidizer Mixing in the Near-Field of Diesel Sprays
Authors: Cellek Mehmet Salih , Bittle Joshua A. , Agrawal Ajay K.
Published: December 2024

Conventional diesel combustion (CDC) utilizes a centrally mounted multi-hole fuel injector spraying fuel into the piston bowl and towards the cylinder wall. This configuration is prone to jet/flame wall impingement causing wetting and flame quenching, higher coolant heat loss, and higher emissions of unburned hydrocarbons, soot, carbon monoxides, etc. Recently, we have introduced peripheral fuel injection (PeFI) whereby fuel is injected at an angle from the periphery of the cylinder head using multiple single-hole injectors. PeFI has been developed to obtain free flames away from the surfaces to minimize heat loss and to reduce emissions by increasing access to the oxidizer both in the near-field of the injector and in the downstream diffusion flame. In this study, 3D computational fluid dynamics (CFD) analysis is utilized to investigate fuel-air mixing in the near-field of diesel sprays with the goal to compare CDC and PeFI strategies. The study utilizes experimentally determined rate of injection (ROI) profiles for multi-hole and single-hole injectors to replicate published data for non-evaporating CDC and PeFI sprays acquired in a pressurized test chamber. The CFD model thus validated is extended to investigate fuel-air mixing in an evaporating spray at ECN Spray A reference conditions of ambient pressure and temperature. Results show significant differences in the flow field in and around the fuel jet and within the chamber for CDC and PeFI cases. PeFI case with its faster initial ROI ramp-up increases initial mixing and achieves faster fuel vaporization compared to those for CDC case. Quantitative analysis reveals that PeFI case provides 20 to 40 percent increase in entrainment at quasi-steady conditions compared to that for CDC case. These benefits of PeFI case are partially offset by its slower ROI at steady conditions, indicating that the single-hole injector should be carefully designed to replace the un-optimized prototype built from the off-the-shelf multi-hole injector.
Heat Release Characteristics of a Volatile, Oxygenated, and Reactive Fuel in a Direct Injection Engine
Authors: LeBlanc Simon , Cong Binghao , Sandhu Navjot , Yu Xiao , Reader Graham , Zheng Ming
Published: December 2024

Compression ignition diesel engines offer a power dense solution for heavy-duty on-road vehicles. The purpose of combustion management for diesel engines primarily concerns the balance of high efficiency and low emissions. Conventional diesel combustion, i.e. single-shot fuel scheduling, is subject to an extended overlap of fuel injection and combustion promoting the diffusion mode of combustion, that is one highly efficient yet prone to form excessive amounts of nitrogen oxides (NOx) and soot emissions. The application of exhaust gas dilution to reduce NOx below regulation limits leads to an increase in smoke emissions, further magnifying the emission control dilemma. Dimethyl ether (DME) contains suitable reactivity for compression ignition engines while also possessing distinct characteristics to diesel, notably physical properties such as volatility and oxygen content, which significantly lowers engine-out soot emissions. In turn, DME enables direct NOx control via oxygen dilution. Nonetheless, the influence of charge dilution towards the combustion heat release behavior of DME persists.

In this study, the heat release pattern of high-pressure DME combustion was investigated in a single-cylinder direct injection engine. The conventional combustion mode was employed, i.e. a single-shot fuel scheduling, with the start of fuel injection fixed at top dead center wherein the in-cylinder temperature and pressure are highest, and the combustion proceeds in an expanding volume. Throughout the study, the fuel injection pressure, engine load, and oxygen dilution were adjusted separately to characterize their influence on the subsequent combustion process. Diesel combustion operated at matching conditions was used to provide reference and relevance to the results. Most notably, the period of diffusion burning was extended in DME following a longer period of injection-combustion overlap. To add, the heat release of DME combustion was repeatedly shorter than diesel owing to the lack of end-burning combustion phase inherent to diesel combustion.
Experimental Studies of Nanosecond Pulse Discharge Plasma on SI Engine
Authors: V. Avaneesh Athreya , Singh Saurabh , Chaturvedi Shivansh , Boggavarapu Prasad , M. Himabindu , Ravikrishna R. V.
Published: December 2024

Non-equilibrium plasma-based ignition systems, such as nano-second plasma (NSP) pulsed discharge and microwave (MW) discharge, have gained significant attention due to their ability to ignite lean fuel-air mixtures. Besides thermal enhancement, NSP produces large amounts of radicals, like O, OH, etc., leading to a lower ignition delay than conventional ignition systems. While the NSP finds its applications in diverse fields, its utilization as an ignition system for spark-ignited engines is explored in this study. The tests were carried out on a natural gas-fuelled 200cc 4-stroke, naturally aspirated spark-ignited engine with a compression ratio of 13. Performance parameters such as engine brake torque, thermal efficiency, brake-specific fuel consumption (BSFC), and exhaust gas emission between conventional and NSP ignition systems have been compared. Based on the in-cylinder pressure data, parameters such as ignition delay, combustion duration, and Coefficient of Variation (CoV) were calculated. The experiment has been carried out at 3000 rpm and 8% manifold throttle opening, corresponding to a low load point. During the experiments, the λ has been varied till the lean operation limit of the engine. With NSP, the lean limit was seen to extend from λ = 1.1 to slightly greater than λ = 1.2. The ignition delay was reduced by 36% at λ = 1.2, with NSP indicating faster combustion. Higher heat release rates were observed with NSP, significantly improving engine performance.
Numerical Study of Buoyancy and Flame Characteristics of Ammonia-Air Flames
Authors: Mathai Joel Reji , Rana Shailendra , Shaalan Amr , Nasim Md Nayer , Trelles Juan Pablo , Mack J. Hunter , Assanis Dimitris , Van Dam Noah
Published: December 2024

There is growing interest in ammonia, NH3, as a zero-carbon fuel for use in transportation as part of broader decarbonization efforts. Ammonia has several advantages as an alternative fuel, including an existing global infrastructure and the ability to be stored as a liquid at room temperature and moderate pressures, thereby increasing its volumetric energy density relative to hydrogen. However, ammonia has a very slow flame speed and can be challenging to ignite. There are growing efforts to develop numerical models of ammonia combustion. However, difficulties still remain to match experimental validation data. The low flame speeds of ammonia flames result in significant buoyancy effects, but buoyancy is neglected in standard modeling and analysis approaches. The buoyancy also affects the flame shape, and therefore can affect the flame speed derived from constant volume combustion chamber (CVCC) experiments. This study examines how well different computational fluid dynamics (CFD) modeling setups are able to capture the effects of buoyancy on ammonia flames, and the sensitivity of flame speeds derived from the CVCC simulations to post-processing and simulation parameters.
Enabling Gaseous Ammonia Use in a Compression Ignition Research Engine
Authors: Ristow Hadlich Rodrigo , Kamal Nabil , Loprete Jason , Sirna Amanda , Trelles Juan Pablo , Van Dam Noah , Mack J. Hunter , Assanis Dimitris
Published: December 2024

With regulations imposing tighter restrictions on carbon emissions, it is crucial to explore the use of carbon-free fuels. Ammonia, NH3, is increasingly being perceived as a dominant hydrogen carrier candidate fuel due to its efficient hydrogen atom arrangement, ease of storage, and for already having an extensive transportation network as the second most traded chemical in the world. There are, however, challenges that still need to be overcome to accommodate the use of gaseous ammonia in a traditional internal combustion engine. To this purpose, a thermodynamic analysis of the heat and mass transfer processes that occur during the withdrawal of the fuel from a compressed gas state is presented to aid in the design of research fueling systems. Moreover, other safety precautions must be taken, including the use of specialized personal protective equipment (PPE) due to the high toxicity of ammonia at relatively low ambient concentrations. The selection of appropriate equipment for the safe handling and use of ammonia in a laboratory setting is detailed, including ammonia-compatible hardware and instrumentation as well as necessary safety considerations inclusive of components such as the pressure regulator, flow meter, thermal generation device to prevent fuel system freezing, and consideration for a HORIBA MEXA 7100 style exhaust gas analyzer. The goal if this work is to provide an overview of the challenges regarding the usage of ammonia as a fuel, as well as guidance on the design process and equipment selection for research engine applications.
Improved Engine Data Acquisition System and Interface to Enable Experimentation With Emerging Alternative Fuels in a Spark-Ignited CFR Engine
Authors: Loprete Jason , Dimosthenous Christos , Assanis Dimitris
Published: December 2024

Existing engine facilities often build upon legacy hardware and assumptions that were once state-of-the-art, but have since become less relevant or even outdated in the face of new research challenges facing the community today. Often, assumptions and simplifications to experimentation or analysis, once necessary to be made due to the computational limitations of the hardware at the time of initial development, are carried forward. These legacy elements can potentially limit the effectiveness of accurately describing key parameters or metrics before, during or post experimentation. The behavior of novel fuels is also not always fully understood, which highlights the need for tools to guide the design of the experimental matrix to avoid unexpected and potentially dangerous outcomes. Determining these key and critical experimentation parameters places additional strain on researchers during both the dry-lab (pre-experimentation), experimentation, and data post-processing phases, which in turn reduces the overall efficiency of the experimental process. With these factors in mind, this manuscript details the conversion of an existing spark-ignited single-cylinder Cooperative Fuel Research (CFR) engine, typically in-service at industrial plants for fuel octane testing or reserved for educational and light-duty research tasks, to a test cell equipped to handle a variety of different emerging alternative fuels. Specifically, modifications to the in-house LabVIEW program and data acquisition system are detailed, with emphasis on providing additional tools to aid in the expediency and more importantly assist in the safety during experiments. This includes the conversion of the existing CFR testing facility from a single liquid or single gaseous fuel capable system to a multi-fuel compatible system, complete with on-the-fly calculations of mass, energy, and volume fractions of existing fuel blends, increased low-speed sampling rates, and a calculating tool to determine scalar quantities required to command fuel flow set-points for a given blend at a particular equivalence ratio and airflow set-point (throttle). Additional factors, such as sensor selection and communication, are discussed with an emphasis on reducing experimental uncertainty. Overall, this work provides insights into possible adjustments and considerations when upgrading existing experimental setups to accommodate emerging alternative fuel use.
A Generalized Additive Modeling Framework Approach for RCCI Combustion Phasing Prediction
Authors: Ankobea-Ansah King L. , Hall Carrie M.
Published: December 2024

Reactivity Controlled Compression Ignition (RCCI) represents a promising combustion strategy in internal combustion (IC) engines, offering high efficiency alongside remarkably low nitrogen oxides (NOx) and soot emissions. The distinctive dual-fuel approach of RCCI demands precise closed-loop control over combustion timing to meet stringent emissions standards while optimizing engine performance. Various data-driven and machine learning (ML) techniques have emerged to address the complexities of RCCI combustion control, but can be unreliable in the face of uncertainties due to limited insights into their underlying models. Achieving an optimal balance between model complexity, interpretability, prediction accuracy, and computational cost is crucial for cycle-by-cycle control and effective fault-tolerant engine management on advanced RCCI engine platforms. In this study, we propose a novel approach utilizing a Generalized Additive Model (GAM) framework for transparent modeling of CA50 (the crank angle at which 50% of the fuel energy is released) to facilitate precise RCCI combustion phasing control and provide exploratory insights for new RCCI experimental designs and control strategies. The proposed methodology is validated with experimental data across 451 steady-state engine operating conditions in Gasoline/Diesel (G/D) and 85%Ethanol (E85)/20%Biodiesel (B20) RCCI fueling regimes. The resulting GAM CA50 models across the various fuel types demonstrated high predictive accuracy greater than 90% Pearson Product-Moment Correlation Coefficient (PPMCC) and fast computational runtime of less than 500 milliseconds (ms) per query in addition to providing interpretability through local effects and individual conditional expectation (ICE) plots.
Methanol Operation in Heavy-Duty DICI Dual-Fuel Engines: Investigating Charge Cooling Effects Using ECN Spray D Data
Authors: Zoumpourlos Konstantinos , Geertsma Rinze , van de Ketterij Robert , Coraddu Andrea
Published: December 2024

Methanol is a promising alternative fuel, which can assist in reducing emissions in heavy-duty dual-fuel (DF) compression ignition (CI) engines. In medium and large bore marine engines, DF operation is achieved through either direct injection (DI) or port fuel injection (PFI) of methanol with diesel acting as a DI pilot fuel for ignition. However, the injection of methanol presents a significant challenge due to its high latent heat of vaporization and decreased lower heating value (LHV) compared to diesel. Therefore, for the same energy content operation, methanol requires around eight times the amount of heat to evaporate completely in comparison to diesel, which results in lower in-cylinder temperatures. This charge cooling effect leads to a strong negative temperature gradient influencing ignition and flame propagation. This paper aims to quantify the cooling effect of methanol in a heavy-duty dual-fuel DICI engine environment. The presented methodology uses Computational Fluid Dynamics (CFD) simulations to model methanol sprays with validation originating from the Engine Combustion Network (ECN) Spray D experimental data. The CFD models operate within the Lagrangian-Eulerian framework in CONVERGE-CFD using the Reynolds Averaged Navier Stokes turbulence modelling. Compared to diesel, injecting methanol with the same energy content exhibited up to 100 K more decreased temperature within the mixture. Consequently, this cooled mixture may pose challenges to combustion stability due to the intense temperature gradients. Nonetheless, lower mixture temperature decreases NOx emissions, which can prove beneficial for high methanol energy fractions in dual-fuel DICI engines.
Comparison of a Full-Scale and a 1:10 Scale Low-Speed Two-Stroke Marine Engine Using Computational Fluid Dynamics
Authors: Chuahy Flavio , Finney Charles E. A. , Kaul Brian C. , Kass Michael D.
Published: December 2024

International marine shipping is a growing component of international trade; a vast majority of all the world’s goods are being transported on large ocean-going vessels. The International Maritime Organization (IMO) introduced the Energy Efficiency Design Index (EEDI) in 2013, a regulatory framework of associated metrics for reducing emissions of CO2 per tonne-mile from shipping by approximately 10% each decade. Therefore, decarbonizing the maritime sector requires the development of new fuel sources. Because of the extremely large physical size of the internal combustion engines present in shipping vessels, experimental iterative development of the engine and fuel system is cost-prohibitive. Thus, the ability to perform combustion system development in a scaled platform that can be more easily operated and modeled computationally is of interest. To that end, scaling relationships are needed to translate the results from a smaller engine to a larger counterpart. Scaling studies to date have been restricted to low scaling ratios, four-stroke light-duty engines, and under-resolved computational fluid dynamic simulations that likely do not accurately capture the physics of scaling. In this work, computational models of a 1:10 scale and a full-scale two-stroke crosshead low-speed marine engine were created and validated against experiments obtained in a real 1:10 scale engine installed at Oak Ridge National Laboratory (ORNL). Due to the large size of the full-scale engine, the model required large high-performance computing resources to be evaluated. The availability of high-performance computing resources at the Department of Energy’s Leadership Computing Facilities is an enabler of the current work. The results of the small- and large-scale engine simulations were compared to analyze the effectiveness of the appropriate scaling laws under these extreme scaling ratio conditions.
Certifying temporal correlations
Authors: Shrotriya Harshank , Kwek Leong-Chuan , Bharti Kishor
Published: December 2024

Self-testing has been established as a major approach for quantum device certification based on experimental statistics with minimal assumptions. However, despite more than 20 years of research effort, most of the self-testing protocols are restricted to spatial scenarios (Bell scenarios), without many temporal generalizations known. Under the scenario of sequential measurements performed on a single quantum system, semi-definite optimization-based techniques have been applied to bound sequential measurement inequalities. Building upon this formalism, we show that the optimizer matrix that saturates such sequential inequalities is unique and, moreover, this uniqueness is robust to small deviations from the quantum bound. Furthermore, we consider a generalized scenario in the presence of quantum channels and highlight analogies to the structure of Bell and sequential inequalities using the pseudo-density matrix formalism. These analogies allow us to show a practical use of maximal violations of sequential inequalities in the form of certification of quantum channels up to isometries.
kV-class Ga2O3 vertical rectifiers fabricated on 4-in. diameter substrates
Authors: Li Jian-Sian , Chiang Chao-Ching , Wan Hsiao-Hsuan , Ren Fan , Liao Yu-Te , Pearton Stephen J.
Published: December 2024

100 μm diameter Schottky and heterojunction vertical Ga2O3 rectifiers were fabricated on ∼10 μm thick drift layers grown on 4-in. diameter bulk Ga2O3 substrates. The uniformity of breakdown voltage was measured on 50 heterojunction devices over a quadrant of the wafer and showed variations from 2 to 8.5 kV, with the higher range correlating with thicker drift layers and lower background doping levels. The median breakdown voltage was ∼6 kV in this area and ∼3 kV in the areas with thinner drift layers and higher doping levels. By contrast, Schottky rectifier breakdown voltages were 0.7–1.8 kV. The minimum on-resistances were in the range of 4–7 mΩ cm2 for Schottky barrier diodes and 5–9 mΩ cm2 for heterojunction diodes, with on-voltages of 0.6–0.75 V for the former and 1.7–1.75 for the latter. The results show the promise of large diameter Ga2O3 substrates in providing high numbers of kV-class rectifiers for electric vehicle charging and other applications.
Rare case of wtTTR amyloidosis and MGUS in a patient with lung adenocarcinoma
Authors: Safdar Ahmad , Anwer Faiz
Published: December 2024

Amyloidosis is a rare, multisystem disease that leads to deposition of misfolded proteins in various organs. This case report presents a patient with cancer with a rare diagnosis of diffuse alveolar–septal transthyretin (TTR) amyloidosis with subsequent protein electrophoresis identifying monoclonal gammopathy of unknown significance. It highlights the association of amyloidosis with malignancy and the importance of including workup for plasma cell dyscrasias in patients found to have TTR amyloidosis. There are major differences in the clinical course and treatment of amyloid light chain and amyloid transthyretin amyloidosis, and evaluation of the precursor protein(s) is critical as a guide for management.
Determinants of adherence towards tuberculosis guidelines among Indonesian private practitioners: a qualitative study
Authors: Lestari Bony Wiem , Afifah Nur , McAllister Susan , Miranda Adriana Viola , Herawati Erna , Hadisoemarto Panji Fortuna , Murray Megan B , van Crevel Reinout , Hill Philip C , Alisjahbana Bachti , Hulscher Marlies
Published: December 2024

Introduction

In high tuberculosis (TB) burden countries, the private sector manages a large proportion of initial visits by presumptive patients with TB. In Indonesia, the second largest contributor of TB cases globally, private practitioners (PPs) often do not adhere to national TB guidelines. A district public–private mix programme to mitigate this issue was started in 2019, yet engagement remains low. This study examines what affects the decisions of Indonesian PPs regarding TB management.

Methods

We performed semistructured in-depth interviews and focus group discussions (FGDs) with 24 PPs and 6 relevant stakeholders. Data collection and analysis were based on Flottorp’s comprehensive and generic checklist on determinants of healthcare professional practice, including seven domains: guideline factors; individual professional barriers; patient factors; professional interactions; incentives and resources; organisational changes capacity and social, legal and political factors. The interviews and FGDs were recorded and transcribed verbatim. Coding and analysis were conducted by using NVivo software.

Results

Barriers that influenced PPs adherence to following the national TB guideline were found in all seven domains, including incoherence between national and international TB management guidelines, the complex referral and financing system, limited access to appropriate diagnostics tools and drugs, and patient preferences. This was further exacerbated by perceived lack of trust between PPs and local governmental stakeholders. In this study, in addition to seventh Flottorp’s domain, we also found the complex nature of TB disease, which also complicates the decision-making process of PPs in TB management.

Conclusion

PPs face several challenges in complying with TB guidelines to enable optimal clinical decision-making.
Food insecurity is associated with greater difficulty accessing care among people living with HIV with or without comorbid non-communicable diseases in western Kenya
Authors: Ardehali Mariam , Kafu Catherine , Vazquez Sanchez Manuel , Wilson-Barthes Marta , Mosong Ben , Pastakia Sonak D , Said Jamil , Tran Dan N , Wachira Juddy , Genberg Becky , Galarraga Omar , Vedanthan Rajesh
Published: December 2024

Introduction

The relationship between food insecurity and access to healthcare in low-resource settings remains unclear. Some studies find that food insecurity is a barrier to accessing care, while others report that food insecurity is associated with a greater need for care, leading to more care utilisation. We use data from the Harambee study in western Kenya to assess the association between food insecurity and difficulty accessing care among people living with HIV (PLWH) with or without comorbid non-communicable diseases (NCDs).

Methods

The Harambee study is a cluster randomised trial that tested the effectiveness of delivering integrated HIV and NCD care for PLWH. In this cross-sectional analysis, we examined baseline data from Harambee participants to investigate the relationship between household food insecurity and difficulty accessing care, using multivariable logistic regression models, controlling for sociodemographic factors and care satisfaction. We tested for effect measure modification by gender and household wealth and stratified analyses by NCD status.

Results

Among 1039 participants, 11.1% reported difficulty accessing care, and 18.9% and 51.9% of participants had moderate and severe food insecurity, respectively. Among those with difficulty accessing care, 73.9% cited transportation issues as the major barrier. Difficulty accessing care was greater with higher levels of food insecurity: among participants with low, moderate and severe food insecurity, 5.9%, 9.7% and 14.4% reported difficulty accessing care, respectively. After adjusting for confounders, severe food insecurity was independently associated with difficulty accessing care (adjusted OR=2.5, 95% CI 1.4 to 4.4). There was no statistical evidence for effect measure modification by gender or wealth.

Conclusions

We found that greater food insecurity was associated with greater difficulty accessing care among PLWH with or without NCDs in rural western Kenya. These findings suggest that addressing social determinants of health may be necessary when implementing integrated HIV and NCD care programmes.
CATHETER II: a randomised controlled trial comparing the clinical effectiveness of various washout policies versus no washout policy in preventing catheter-associated complications in adults living with long-term catheters
Authors: Abdel-fattah Mohamed , Omar Muhammad Imran , Johnson Diana , Cooper David , Constable Lynda , Tripathee Sheela , MacLennan Sara J , Dimitropoulos Konstantinos , Evans Suzanne , Hashim Hashim , Kilonzo Mary , Larcombe James , Little Paul , Murchie Peter , Myint Phyo Kyaw , N'Dow James , Paterson Catherine , Powell Karen , Scotland Graham , Thiruchelvam Nikesh , Young Amanda , Cotton Seonaidh , Norrie John , MacLennan Graeme
Published: December 2024

Objectives

Do weekly prophylactic saline or acidic catheter washouts in addition to standard long-term catheter (LTC) care improve the outcomes of adults with LTC compared with standard LTC care only.

Design

Three-arm superiority open-label randomised controlled trial.

Setting

UK community-based study.

Participants

80 adults with LTC (any type/route) ≥28 days in situ with no plans to discontinue and able to self-manage the washouts/study documentation with/without a carer.

Interventions

Randomly allocated (26:27:27) to receive standard LTC care with weekly saline or weekly acidic or no prophylactic washouts for up to 24 months.

Primary and secondary outcome measures

The primary outcome was catheter blockage requiring intervention (per 1000 catheter days). Secondary outcomes were symptomatic catheter-associated urinary tract infection (S-CAUTI) requiring antibiotics, adverse events, participants’ quality of life and day-to-day activities, acceptability and adherence.

Results

Outcomes reported for 25 saline, 27 acidic and 26 control participants. LTC blockages (per 1000 catheter days) requiring treatment were 9.96, 10.53 and 20.92 in the saline, acidic and control groups, respectively. The incident rate ratio (IRR) favours the washout groups (saline 0.65 (97.5% CI 0.24 to 1.77); p=0.33 and acidic 0.59 (97.5% CI 0.22 to 1.63); p=0.25), although not statistically significant. The S-CAUTI rate (per 1000 catheter days) was 3.71, 6.72 and 8.05 in the saline, acidic and control groups, respectively. The IRR favours the saline group (saline 0.40 (97.5% CI 0.20 to 0.80); p=0.003 and acidic 0.98 (97.5% CI 0.54 to 1.78); p=0.93). The trial closed before reaching target recruitment due to reduced research capacity during the COVID-19 pandemic.

Conclusions

Early closure and small sample size limits our ability to provide a definite answer. However, the observed non-statistically significant differences over control are favourable for lower rates of LTC blockages without a concomitant rise in S-CAUTI. The results support a multinational randomised controlled trial of catheter washouts in patients with LTC to ascertain their clinical and cost-effectiveness.

Trial registration number

ISRCTN17116445.
Analysis of literature-derived duplicate records in the FDA Adverse Event Reporting System (FAERS) database
Authors: Han Weiru , Morris Robert , Bu Kun , Zhu Tianrui , Huang Hong , Cheng Feng
Published: December 2024

The FDA Adverse Event Reporting System (FAERS) is a large-scale repository of reports concerning adverse drug events (ADEs). The same published clinical study or report may be reviewed by multiple companies or healthcare professionals and reported separately to the FDA, leading to a significant presence of duplicate reports in FAERS. These duplicate records can result in the identification of false associations between a given drug and an ADE. In this study, we first assessed the consistency of drug and ADE information in FAERS reports from Alzheimer’s disease patients. Our findings showed greater congruence in drug-related information compared to ADE-related information, likely due to the greater heterogeneity and variety of terms or phrases used to describe ADEs. We then demonstrated that text comparison methods are effective in identifying duplicate records based on literature citations, testing 10 different comparison functions for their overall efficacy. Token-based methods (such as COSINE, QGRAM, and JACCARD), edit-based approaches (including OSA, LV, and DL), and sequence-based techniques like LCS have proven highly effective in accurately detecting identical publications within free text, demonstrating both high sensitivity and specificity. These results offer valuable insights for identifying duplicate FAERS reports and improving the reliability of detected associations between drugs and ADEs.
Aspects of rotating anisotropic dark energy stars
Authors: Jyothilakshmi O. P. , Naik Lakshmi J. , Sreekanth V.
Published: December 2024

By employing modified Chaplygin fluid prescription for the dark energy, we construct slowly rotating isotropic and anisotropic dark energy stars. The slow rotation is incorporated via general relativistic Hartle–Thorne formalism; whereas the anisotropy is introduced through Bowers–Liang prescription. We consider both the monopole and quadrupole deformations and present a complete analysis of rotating dark energy stars. By numerically solving the rotating stellar structure equations in presence of anisotropy, we analyse and quantify various properties of dark energy stars such as mass (M), radius, mass deformation, angular momentum (J), moment of inertia, and quadrupole moment (Q), for three different equation of state parameters. We find that anisotropic slow rotation results in significant deformation of stellar mass and thereby affects other global properties studied. For the values of angular frequencies considered, the effect of anisotropy on the stellar structure is found to be more prominent than that due to rotation. The dimensionless quadrupole moment

$$QM/J^2$$

Q
M
/

J
2

measuring deviation from a Kerr metric black hole was obtained for anisotropic dark energy stars. We observe that dark energy stars with higher anisotropic strength tend to approach the Kerr solution more closely. We report that our results have considerable agreement with various astrophysical observational measurements. We also find that the dimensionless quadrupole moments of anisotropic dark energy stars corresponding to the canonical mass

$${\bar{q}}_{1.4}$$

q

¯

1.4

have a similar range of values as that of isotropic neutron stars and strange stars.
Effect of scalar condensation on fermionic pole-skipping
Authors: Baishya Banashree , Chakrabarti Sayan , Maity Debaprasad
Published: December 2024

In this paper, we investigated the holographic fermionic pole-skipping phenomena for a class of interacting theory in a charged AdS black hole background. We have studied two types of fermion-scalar interactions in the bulk: dipole and Yukawa type interaction. Depending upon the interaction we introduced both real and charged scalar fields. We have particularly analyzed the effect of scalar condensation on the fermionic pole-skipping points and discussed their behaviour near critical temperatures.
Wisdom, Resilience, and Well-Being in Later Life
Authors: Jeste Dilip V. , Alexopoulos George S. , Blazer Dan G. , Lavretsky Helen , Sachdev Perminder S. , Reynolds Charles F.
Published: December 2024

As the numbers of older adults continue to increase globally, the need for facilitating healthy aging has become critical. While a physically healthy lifestyle, including exercise and diet, is important, recent research has highlighted a major impact of psychosocial determinants of health, such as resilience, wisdom, positive social connections, and mental well-being, on whole health. This article focuses on keeping the mind and brain healthy with psychosocially active aging. It has six sections: Philosophy Concepts of Wisdom, Resilience, and Well-Being; Wisdom: Clinical, Neurobiological, and Evolutionary Perspectives; Resilience, Adaptation, and Augmentation; Psychological Resilience, Brain Health, and Whole Person Health; Preventing Depression and Promoting Resilience and Well-Being in Old Age; and The Centenarian as a Model of Resilience and Well-Being. We discuss the biopsychosocial mechanisms and effectiveness of healthy lifestyle strategies and propose a framework for future research and its practical implications for promoting wisdom, resilience, and well-being at the individual, societal, and policy levels.
Hierarchical Reactions Involving Dynamic Structural Changes in Lithium-Ion Batteries during Overcharge Using Advanced Analytical Techniques
Authors: Shi Xian , Watanabe Toshiki , Yamamoto Kentaro , Kumar Mukesh , Thakur Neha , Matsunaga Toshiyuki , Fujii Masanori , Kinoshita Hajime , Iba Hideki , Nagamine Masayuki , Kanamura Kiyoshi , Uchimoto Yoshiharu
Published: December 2024

High-Ni cathode materials are promising for lithium-ion batteries compared to conventional cathode materials because of relatively high energy density and low cost. High-Ni cathodes are inherently thermally unstable, and when used in large scale batteries, they can cause serious problems such as thermal runaway and associated destruction of the internal structure. For practical use, it is necessary to understand the internal phenomena when they are incorporated into large scale batteries. We examined the stacked electrode structural change inside pouch cells with approximately 1 Ah capacity during over charging, which includes LiNi0.8Mn0.1Co0.1O2, LiNi0.6Mn0.2Co0.2O2, and LiCoO2 athodes, by using synchrotron-based operando X-ray radiography. In addition, the bulk crystalline, electronic, and local structures of these materials as well as surface electronic structure changes during overcharging were also analyzed. We found that as the amount of Ni-content in the cathodes increase, destabilization of surface oxygen and structural phase transitions occur at smaller state of charge, leading to faster and more severe collapse of the stacked electrode structure inside the pouch cells. This finding of a relationship of hierarchical structural changes from the cathode surface to the pouch cell is useful for the safe use of lithium-ion batteries with high energy density containing high-Ni cathodes.
Self-Diffusion in Bulk Lithium and Sodium and Its Impact on the Whisker Growth during Electrodeposition
Authors: Sergeev Artem V. , Kondratyeva Yevgeniya O. , Borodin Konstantin O. , Yashina Lada V.
Published: December 2024

Here we propose computational insight into mass transport in bulk polycrystalline lithium and sodium in relation to the whisker growth problem. Different mechanisms of self-diffusion were evaluated at both atomistic and macroscopic levels based on the results of the molecular dynamics simulations. It was found that in sodium the vacancy mechanism of self-diffusion prevails due to abundance of this type of defects. In contrast, in lithium, vacancy diffusion makes a smaller contribution than the interstitials diffusion, while the mass transfer along the grain boundaries is predicted to have major impact. Overall self-diffusion in sodium is approximately three orders of magnitude faster than in lithium. Therefore, a reasonable approach to solving the lithium whisker problem would be to promote the self-diffusion, particularly by reducing the average grain size. For sodium mass transport seems to be not so critical factor.
Prelithiating Silicon-based Anodes using Lithium-excess Layered Positive Electrode Materials
Authors: Rathore Divya , Dressler R. A. , Vain Fanny , Tariq Hassaan , Johnson Michel , Dahn J. R.
Published: December 2024

With the increasing commercialization of silicon-based anodes, their high first-cycle irreversible capacity becomes a critical issue to address. Future cycles may also require additional lithium due to the evolution of the anode’s solid electrolyte interphase. This work introduces Li-excess layered Li1.11(Ni0.5Mn0.5)0.89O2 (Li-excess NMC550) as a suitable cathode choice to provide additional lithium reserves to the cell. The excess lithium can be irreversibly removed from the cathode structure when the cell is subjected to voltages greater than 4.4 V, making it a good choice for prelithiating Si-based cells without requiring any additional processing. In addition, the Li-excess NMC550 does not display voltage fade typical of Li-rich and Mn-rich materials with more Mn than Ni atoms in the structure. This strategy is shown in this work with NMC550| silicon/carbon (Si/C) cells. Cells were cycled to an initial upper cutoff of 4.6 V to transfer excess lithium from the cathode to the Si-based anode, followed by typical cycling within a stable voltage window. An 11% excess lithium reserve enhances cell energy density and prevents early capacity loss associated with lithium inventory depletion.
Electrodeposition of Extremely Cu-Rich CuPd Bimetallic Nanoparticles from an Amide-Type Hydrophobic Protic Ionic Liquid
Authors: Yu Chia-Lin , Chen Hsing-Yin , Lee Chien-Liang , Chen Po-Yu
Published: December 2024

Cupric oxide (CuO) and palladium(II) acetate (Pd(Ac)2) were dissolved into the amide-type hydrophobic protic ionic liquid (IL), protonated-betaine bis((trifluoromethyl)sulfonyl)amide ([Hbet][TFSA]), to produce the Cu(II) and Pd(II) species for the electrodeposition of metallic Cu, Pd, and CuPd nanoparticles (NPs). Unlike the electrodeposition conducted in common aqueous electrolytes containing the equivalent amounts of Cu and Pd ions, Cu-rich rather than Pd-rich CuPd co-deposits were obtained from the IL [Hbet][TFSA]; which might result from the retardation of Pd deposition on preferentially electrodeposited Cu surface or the formation of a new metal species when both metal ions co-existed in the IL, leading to an uncommon large overpotential needed to reduce the species into Pd metal. The surface morphologies of CuPd NPs significantly relied on their elemental compositions that could be controlled by the concentration of Pd(II) and/or the applied electrodeposition potential. CuPd NPs with different Pd contents showed very different responses in the reaction current of nitrate reduction. Nevertheless, the CuPd NPs regardless of the Pd contents showed advantages over the Cu nanoparticles in the electrochemical reduction of nitrate, which might be due to the synergistic effects between the Cu and Pd atoms.
MOF-derived Sheet-like E-Ru/Mo/Mo2C with Abundant Exposed Active Sites for Advanced Electrocatalytic Hydrogen Evolution
Authors: Zhou Fuxiang , Zhu Min , Liu Huan , Deng Qinghua , Yang Chenghan , Huang Jinqiang , Zhang Yiwei
Published: December 2024

A Ru/Mo/Mo2C sheet-structured composite electrocatalyst was synthesized through a meticulous methodology involving etching pretreatment, impregnation, and subsequent calcination. This work delves into the intricacies of how the incorporation of Ru and the application of etching pretreatment influence the compositional makeup, morphological characteristics, electronic configuration, and, most notably, the hydrogen evolution reaction (HER) performance of the catalyst within the context of water electrolysis. Specifically, it was observed that the introduction of Ru catalyzed the formation of Mo and Mo2C phases, while the etching pretreatment played a pivotal role in augmenting the specific surface area of the catalyst, thereby facilitating the availability of an enriched landscape of active sites and modifying the electronic coupling between Ru and Mo species. Electrochemical evaluations revealed that the optimized E-Ru/Mo/Mo2C-3 catalyst exhibited remarkable HER kinetics, manifested by a minimal overpotential of 39.7 mV at a benchmark current density of 10 mA cm−2 and a favorable Tafel slope of 14.5 mV dec−1 in an alkaline medium. This comprehensive investigation offers profound insights into the rational design of metal-organic framework (MOF)-derived electrocatalysts, paving the way for the development of highly efficient HER catalysts tailored for water electrolysis applications.