bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Thermal Cycling on the Microstructure of Nuclear Grade Dissimilar Metal Weld
Authors: Luo Wenwei , Hu Mengjia , Luo Xiaowei , Shi Li , Wu Xinxin
Published: November 2024

As the crucial structure in the pressure boundary of the steam generator in the high-temperature gas-cooled reactor (HTGR), it is essential to investigate the microstructure of T22/800H dissimilar metal weld (DMW) under thermal cycling. This is especially critical in the context of rapid temperature fluctuations under extreme conditions, which are likely to inflict irreparable damage on the material’s microstructure, thus posing a severe threat to the service life of the DMW. T22 and 800H base metal (BM) were welded by tungsten inert gas (TIG) welding, filling with UNS N06082 inserts. To investigate the impact of thermal cycling under extreme conditions on the microstructure of DWM, and to accelerate the evolution of microscopic phenomena, simulated thermal cycling tests were carried out at 500°C with a holding time of 1 hour per cycle and 300 cycles at two ramp-up/down rates of 3°C/min and 8°C/min between room temperature and 500°C, respectively, much more serious than the temperature evolution in start-ups and shutdowns during the operation of HTGR. Characterization of the microstructure of three typical failure-prone areas of T22/800H DMWs, namely the T22 base material (BM), the T22 heat-affected zone (HAZ) and the T22/WM fusion zone by optical microscopy (OM), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), compared with that of the as-welded.

It is obtained that limited cavities formed at the interface of T22 BM and the weld fusion zone (FZ), due to the prominent difference of thermal expansion, which contributes to the creep and fatigue, especially in the thermal cycling. Some cavities were also found in the fine-grained heat-affected zone (FGHAZ) of T22, ranging from 100 to 700nm in size. It is predicted that the cavities in FGHAZ were resulted from stress relief without preheat and post-weld heat treatment during the manufacturing of T22/800H DMWs. In addition, a mount of cavities, less than 100nm in size, were observed in the T22 BM during the thermal cycling test at 8°C/min; meanwhile, there were also some cavities, ranging from 100 to 300nm, found in the coarse-grained heat-affected zone (CGHAZ). It is supposed that the differences of thermal-physical properties, such as thermal expansion and hardness, make sense for the small cavities under thermal cycling. Sharp notches resulted from oxidization and thermal stress were found at the interfaces between T22 BM and weld metal, except for specimens without simulated thermal cycling.
Coarse Mesh Generation for CMFD Acceleration in SARAX-LAVENDER Code
Authors: Xu Haoxiang , Zheng Youqi , Xiao Bowen , Wu Hongchun
Published: November 2024

A coarse mesh generation algorithm is implemented in SARAX-LAVENDER code based on mesh merging, aiming at providing the foundation for a CMFD acceleration scheme. Originated from Navigation Mesh construction method in Recast code, this algorithm is slightly altered to improve performance on a reactor geometry. The algorithm can handle regular triangular node in structured geometry as well as Delaunay triangle mesh in arbitrary unstructured geometry. Such an algorithm holds several advantages as follows: (1) No extra effort is required during regular triangle or Delaunay triangle mesh generation procedure. (2) The coarse mesh generated by triangle mesh consists of only convex polygons. (3) The boundary surfaces between coarse mesh can be exactly preserved by existing triangular node. (4) The maximum edge number of generated polygons could be easily adjusted to adapt different geometry. When set to 3, the algorithm could transfer triangle mesh directly into coarse mesh format without mesh merging, making it easy to implement a two-level spatial CMFD acceleration scheme. (5) The algorithm naturally adapts the geometry after domain decomposition, which is required for parallel computing. Coarse mesh number ranges from one sixth to one third of original triangle mesh number in hexagonal, rectangle or arbitrary unstructured geometry. Similar reduction could be achieved in a MPI parallel computing condition with CPU number from 2 up to 64.
Sigma Embrittlement Evaluation Test for Dissimilar Welding Between F6NM and FXM-19
Authors: Osafune Ryoji , Tanabe Yoshihiro , Yagi Daisuke , Koike Daisuke
Published: November 2024

In dissimilar welds between martensitic stainless steel F6NM and nitrogen-strengthened austenitic stainless steel FXM-19, type 209 austenitic welding materials is used to match the mechanical properties and chemical composition of FXM-19. The welds of F6NM must be subjected to Post-Weld Heat Treatment (PWHT) to restore ductility and toughness. Therefore, sigma embrittlement is a concern for ER209 buttering welds as they are subjected to PWHT. In this research, the mechanical properties and microstructure of dissimilar welds of F6NM+FXM-19 were investigated.

There was no significant difference in the volume fraction of sigma phase between the buttering weld metal (PWHT) and the groove weld metal (As weld) for each welding process. Therefore, sigma phase transformation by PWHT did not occur. Submerged Arc Welding (SAW) and Gas Metal Arc Welding with 100%Ar gas shield (GMAW 100%Ar) were found to have good mechanical properties. In Gas Tungsten Arc Welding (GTAW), the impact value was below the required value in the Charpy impact test of the buttering weld metal. SAW and GMAW 100%Ar were found to be applicable welding processes for this dissimilar weld joint.
Study on the Oxidation/Corrosion Behavior of Small Modular Lead-Bismuth-Cooled Fast Reactor Summer
Authors: Zhang Junjia , Zhang Kefan , Chen Hongli
Published: November 2024

The issue of corrosion is one of the constraints on the safe operation of the Small Modular Lead-cooled Fast Reactor (SUMMER). In order to understand the oxidation/corrosion behavior of SUMMER during operation and optimize the design to ensure its safe operation, a simulation analysis program, KMC-SUBtra-MC, was employed to simulate SUMMER. The appropriate oxygen control range was theoretically derived, and simulations were conducted at an oxygen concentration of 1 × 10−6 wt.% to calculate the oxidation film thickness, corrosion thickness, and outlet oxygen concentration for both the hottest and average components. It was observed that SUMMER can maintain a dual-phase oxide film structure during operation, and the axial distribution of the oxidation film thickness is temperature-dependent. Oxygen depletion occurred during the initial stages of operation. Pre-oxidation of SUMMER components was found to improve the oxygen depletion situation and reduce the pressure in the oxygen control system.
Study on the Remelting Process of the Debris Bed in the Lower Head of Reactor Pressure Vessel Based on Lattice Boltzmann Method
Authors: Shi Shang , Li Liangxing , Ma Weimin , Zeng Xiao , Yuan Yidan , Lei Zhenxin , Xiang Zutao , Xu Xiangyang
Published: November 2024

The retention of core melt (corium) in the lower head of the reactor pressure vessel (RPV) has been considered as a severe accident management strategy to maintain the RPV integrity of a light water reactor. To study the debris bed remelting process in the lower head of the reactor pressure vessel, as well to explore the influence of external cooling on the debris bed remelting process, the Lattice Boltzmann Method (LBM) is employed to simulate the remelting process of the debris bed. The Lattice Boltzmann Method, as a powerful numerical method for simulating fluid flow and complex physical processes, has been widely used in the solution of solid-liquid phase change problems in recent years. Thermal Lattice Boltzmann Method (TLBM) based on total enthalpy is adopted to handle the latent heat in the phase change process, and the Immersed Boundary Method (IBM) is used to account for the velocity and boundary conditions of the solid-liquid phase interface. In addition, the calculation results from the present LBM model are also compared with the experimental data based on the COREM experimental system which is design and constructed to investigate the melting process of a debris bed packed with multi-component particles. The simulation results and experimental results have good consistency in the natural convection phenomenon during the melting process, which is been simulated successfully.
Influence of Multi-Hole Sparger Geometry on the Chugging Regime
Authors: Berti Luca , Lo Frano Rosa , d’Errico Francesco , Aquaro Donato
Published: November 2024

Several experimental tests have been carried out at the University of Pisa using the Large-Scale Experimental Facility simulating the behaviour of the Vacuum Vessel Pressure Suppression System of ITER fusion reactor.

The experiments were carried out by injecting steam produced by an electric steam generator through a multi-hole sparger into a condensation tank, known as Experimental Test Tank, containing 55 m3 of water. Two spargers called sparger A (a reduced scale of ITER sparger) and sparger B (a full scale of ITER sparger) were used during the experimental campaign. The geometry of the two spargers differs for the arrangement of the holes at the external (injecting) surface.

This study compares the behavior of the two spargers by analyzing two experimental tests. The unstable chugging regime was also considered.

The image analysis of the videos permitted the comparison of the steam bubble dynamics.

The geometry of sparger B leads to the coalescence of the entire steam mass, while the sparger A developed two distinct steam bubbles which do not coalesce together.

The analysis of the strain gauges and accelerometer signal allowed to compare the structural-dynamic response of the steam bubble collapse. This preliminary analysis showed the strong influence of the sparger geometry on the steam bubble dynamics and on the developed load on the sparger.
SIMMER-III Code Simulation of High-Pressure Water-Lead Interaction in Westinghouse’s LEWIN Test Facility
Authors: Bellomo Alessandro , Massone Mattia , Gianfelici Simone , Martini Fabio , Lee Sung Jin , Tarantino Mariano , Galleni Francesco , Pucciarelli Andrea , Pesetti Alessio
Published: November 2024

The Lead-cooled Fast Reactor (LFR) is one of the six advanced reactor system types selected in the Generation-IV (Gen IV) program. Westinghouse (WEC) is developing a highly simplified, passively safe, medium-size, economic Gen-IV LFR as its next-generation utility-scale nuclear power plant. Designed as a pool-type reactor, the Westinghouse LFR has all primary components located inside the reactor vessel (RV). The heat transfer from the primary coolant to the secondary side is accomplished through three primary heat exchangers (PHEs).

The PHE failure is one of the safety events considered in designing the Westinghouse LFR. Therefore, the transient behavior of the molten lead pool following PHE failure should be investigated to evaluate its consequences and to adopt effective mitigation measures. Based on the secondary system considered in the WEC LFR conceptual design, a high-pressure water injection into molten lead is considered for the characterization of coolant-coolant interaction (CCI) during a postulated PHE failure accident scenario.

In the framework of the collaboration between Westinghouse and ENEA, a separate effect testing (SET) facility named LEWIN (LEad-to-Water INteraction) was designed and built, with the aim of identifying and quantifying the main phenomena that occur during the high-pressure water injection into molten lead.

To support the conceptual design and experimental pre-test phase, the SIMMER-III (S-III) computer code was used to model the interaction vessel, the injection line, and the dump line. The choice of this code is justified by its distinctive fluid-dynamics features: it uses two-dimensional meshes to simulate a multi-velocity field with multiphase and multicomponent materials. However, since the original version of the S-III code cannot simulate two different types of coolant at the same time, code modifications have been introduced to enable modeling of the lead-water interaction.

This paper aims to assess the capability of SIMMER in simulating the main phenomena expected to take place during the experimental transients in LEWIN, and hence to illustrate the pioneering role the code can play, especially in studying the phase change phenomenology in lead-water thermal-hydraulics systems. The simulation results show the flashing of the water injected into the molten lead, the growth of water vapor bubbles in the lead pool, the lead pool swelling, and the lead sloshing motion. The pressure peak, onset of a choked flow, and pressurization of the cover gas region can be observed as well.

This activity has also the objective of supporting a systematic validation and verification (V&V) program for the SIMMER code assessment based on test problems involving lead, lead-bismuth eutectic alloy, and water systems, to advance the code as a next-generation standard tool for LFR safety analysis.
Progress in Isolation Analysis and Experimental Research of HPR1000 Nuclear Island Plant
Authors: Shi Chencheng , Chen Jian , Sun Xiaoying , Yang Xiaoyi , Ren Hehuan
Published: November 2024

At present, the PGA of the standardized design site of HPR1000 is 0.3g, which can meet the seismic requirements of the plant site at home and abroad. However, domestic nuclear power plant sites are scarce resources. When plant sites with higher intensity earthquake appear in the future, the seismic isolation technology can effectively reduce the seismic action on the superstructure and equipment to the desired level without being limited by the design ground motion size of the plant site, which can not only improve the safety and economy of HPR1000, but also broaden the application scope of HPR1000 standardized design in plant site. China Nuclear Power Engineering Company (CNPE) has carried out research on seismic isolation technology for nuclear power plants, and has successfully applied it in nuclear safety related plant. The main research includes: design and analysis of isolation scheme, influence analysis of soil-structure interaction on isolated plant, influence analysis of commercial aircraft impact on isolated nuclear island plant, and shaking table test of isolated nuclear safety related plant.
Analysis of the Dynamic Behaviour of a Nuclear Containment Structure Under Missile Impact
Authors: Lo Frano Rosa , Cancemi Salvatore Angelo , Angelucci Michela , Pugliese Giovanni
Published: November 2024

The evaluation of the integrity of the NPP against a missile impact requires considerable attention because of the complexity of the accident scenario and consequences it may cause. To assess whether such type of thread may determine the failure of the safeguard system, the effects of both the impact force and the resistance force must be determined.

This study deals with the currently used general procedures and criteria. Particularly, it focuses on the evaluation of global and local effects caused by an impacting missile on the reinforced concrete structural elements, like the containment system.

To the aim, a numerical approach based on the use of the finite element (FE) code was adopted. As the analysis of reinforced concrete is made complex by the several arising dominant energy absorbing and failure modes mechanisms, a methodology which was validated with reference to experimental data available in the open literature from large-scale impact tests was employed. Therefore, a 3D FE model of the RCS was implemented with structural 3-D Solid element to represent the dynamic interaction occurring at the impact surface.

The strain-rate effects are considered through the dynamic increase factor (DIF) to account for strain-rate hardening effects on both deformation and failure; for the steel behavior the Cowper-Symonds’ model was assumed.

Results showed that at the instant of the impact, the intense shock wave that characterize the instant of the projectile-target impact is responsible of the cracking, and penetration of the RCS wall. For a striking velocity of about 150 m/s the wall penetration extends over about 80 mm.
Development and Verification of a Few-Group Parameters Calculation Code TMSR-LINK for Molten Salt Reactor
Authors: Wang Kailong , Cui Yong , Zou Chunyan , Chen Jingen , Cai Xiangzhou
Published: November 2024

Assembly few-group cross-sections are important parameters for nuclear design of reactor with the ‘two-step’ strategy based on deterministic theory. The unique physical mechanism and operation mode of liquid-fueled Molten Salt Reactor (MSR) make the calculation method of assembly few-group cross-sections different from that of the traditional solid-fueled reactor. In this work, a few-group parameters calculation code for MSR named TMSR-LINK is developed based on OpenMC, and two single assembly benchmarks of pressurized water reactor and MSR are first verified and analyzed; Simultaneously, macro cross-section libraries of the Molten Salt Reactor Experiment (MSRE) are prepared and provided to the MSR specific neutronics/thermal-hydraulics (TH) coupling code TMSR3D based on advanced nodal method, by which the reactivity loss caused by fuel flow and temperature distributions of graphite and fuel salt in the hottest channel are calculated and compared with the experimental data and the results from similar code; Finally, the steady-state characteristics of MSRE under different operation power are also probed. The results indicate that TMSR-LINK can provide a reasonable description for the benchmarks, which verified the accuracy of the developed code. The neutronics-TH coupling simulation results of the whole core for MSRE agree well with the experiments and exhibit a comparable precision against the similar code, this means that TMSR-LINK can provide accurate macro cross-section data for the MSR specific neutronics-TH coupling analysis code.
Evaporation of Alkali Metal Sodium Droplet in the Circular Tube
Authors: Tang Songsheng , Guo Kailun , Tian Shiyu , Ma Yugao , Zhao Jinkun , Su Guanghui , Qiu Suizheng , Tian Wenxi
Published: November 2024

High-temperature heat pipe is a passive and efficient heat transfer element, which is generally filled with a certain mass of alkali metal as the heat transfer medium, and utilizes vapor-liquid phase change to efficiently transfer heat from the evaporation section to the condensation section of the heat pipe. In the normal operation of high-temperature heat pipe, the alkali metal will experience evaporation in the evaporation section, vapor diffusion in the adiabatic section, condensation in the condensation section, and reflux under the action of capillary force of the wick structure and other complex heat and mass transfer behaviors. This study focuses on the evaporation behavior of sodium alkali metal inside a high-temperature heat pipe. First of all, an experimental rig is constructed to visualize the evaporation behavior of alkali metal sodium droplets, which mainly includes the alkali metal sodium purification system (to remove the kerosene and impurities inside the commercial sodium to ensure the high purity of sodium), the visual measurement system (to record the droplet morphology), and the constant-temperature and constant-pressure argon system (to provide a high-purity argon environment to avoid the chemical reaction between sodium and the water vapor and oxygen in the air during the experimental process and to provide different temperature and pressure environments for the evaporation of sodium). Then, the evaporation behavior of alkali metal sodium droplets in a circular tube with different wall temperatures and pressure is experimentally investigated by using the previously constructed experimental rig, and the morphological changes of the droplets during the evaporation process were recorded by a high-speed camera. After that, the image analysis software ImageJ is used to analyze the droplet morphology to obtain the change curves of droplet height, contact line length, and contact angle with time during the evaporation of sodium alkali droplets. And the curves are further analyzed to obtain the information of sodium droplet evaporation mode and evaporation rate. By comparing and analyzing the experimental data of sodium droplet evaporation from round tubes with different temperatures and ambient pressures, the influence of the temperature and ambient pressures on the evaporation behavior of sodium droplets is obtained. In this study, the first experimental data of sodium alkali droplet evaporation in a high-temperature heat pipe is obtained by visualization experimental means, which reveals the mechanism of sodium droplet evaporation and lays a foundation for further improvement of the existing heat pipe simulation model.
Affect and Performance Across Double-Elimination Tournaments: A Field Study of Super Smash Bros Competitors
Authors: Nolla Kyle , Reber Paul , Beeman Mark
Published: November 2024

Esports provide an opportunity to study the relationship between affect and competitive performance in highly structured, yet ecologically valid, environments. In this study, we examine self-ratings of affect, performance pressure, and self-other focus within 90 competitors over the course of 327 sets of games in national-level Super Smash Bros tournaments. Within competitors, higher arousal is associated with loss in the next tournament set, even when controlling for known predictors of outcome, such as competitor and opponent predicted performance, time, and grouping by person. Mediation analyses suggest that arousal does not mediate the relationship between perceived performance pressure and outcome, nor does self-focus mediate the relationship between arousal and loss. We found evidence for a negative spillover effect, where performance was worse when a competitor played more sets than their opponent. In all, results suggest that esports competitors may benefit from emotion regulation skills training to down-regulate arousal, maintain effort, and optimize performance.
Dedicated developmental programing for group-supporting behaviors in eusocial honeybees
Authors: Sommer Vivien , Seiler Jana , Sturm Alina , Köhnen Sven , Wagner Anna , Blut Christina , Rössler Wolfgang , Goodwin Stephen F. , Grünewald Bernd , Beye Martin
Published: November 2024

The evolutionary changes from solitary to eusocial living in vertebrates and invertebrates are associated with the diversification of social interactions and the development of queen and worker castes. Despite strong innate patterns, our understanding of the mechanisms manifesting these sophisticated behaviors is still rudimentary. Here, we show that
doublesex
(
dsx
) manifests group-supporting behaviors in the honeybee (
Apis mellifera
) worker caste. Computer-based individual behavioral tracking of worker bees with biallelic stop mutations in colonies revealed that the
dsx
gene is required for the rate and duration of group-supporting behavior that scales the relationship between bees and their work. General sensorimotor functions remained unaffected. Unexpectedly, unlike in other insects, the
dsx
gene is required for the neuronal wiring of the mushroom body in which the gene is spatially restricted expressed. Together, our study establishes dedicated programming for group-supporting behaviors and provides insight into the connection between development in the neuronal circuitry and behaviors regulating the formation of a eusocial society.
Bioinspired gelated cell sheet–supported lactobacillus biofilm for aerobic vaginitis diagnosis and treatment
Authors: Gui Yueyue , Sun Qingfei , Li Kexin , Lin Longjia , Zhou Han , Ma Jiehua , Li Chao
Published: November 2024

Aerobic vaginitis (AV) is a long-standing inflammatory disease that affects female patients. The use of antibiotics is a common means for AV treatment, but it will indiscriminately kill both pathogenic bacteria and beneficial strains, which easily causes vaginal dysbacteriosis and infection recurrence. Herein, we describe a bioinspired strategy for fabricating gelated cell sheet–supported lactobacillus biofilms (GCS-LBs) for AV treatment. Compared with common planktonic probiotic formulations, probiotic biofilms forming on a robust GCS exhibit enhanced stress tolerance and better colonization capacity in the mouse vagina. Moreover, DNA nanodevices are decorated on the GCS and dynamically report the microenvironment change of biofilms for timely evaluating bacterium activity, both in vitro and in vivo. Consequently, GCS-LBs are used for treating AV in an
Escherichia coli
–infected mouse model, which shows enhanced therapeutic efficacy compared with conventional antibiotic or lactobacillus monotherapy. Overall, the GCS-LB shows promise as a potent multifunctional tool to combat bacterial infection.
Monocytes and their doppelgängers: An immunological crossroads
Authors: Mildner Alexander , Yona Simon
Published: November 2024

Identity confusion has emerged in the field of monocyte research with the identification of monocyte-like “doppelgänger” populations that exhibit phenotypical traits of classical monocytes but seem to vary in their origin, function, or migration behavior.
Magnon Supercurrent and the Phase Slippage in an Yttrium Iron Garnet Film
Authors: Bunkov Yu. M. , Belotelov V. I. , Vetoshko P. M. , Knyazev G. A. , Kuzmichev A. N. , Petrov P. E.
Published: November 2024

Exactly forty years ago, the spin superfluidity and Bose–Einstein condensation of magnons in superfluid antiferromagnetic 3He-B were discovered. In this work, the existence of spin superfluidity and phase slippage in an yttrium iron garnet film at room temperature is demonstrated using the optical Faraday effect. The s-patial distribution of the phase and amplitude of the spin precession under the conditions of magnon Bose‒Einstein condensation are studied by varying the pump phase difference between two strip lines exciting magnons.
Folliculotropic mycosis fungoides with leukaemic involvement in middle childhood: a rare encounter
Authors: Tripathi Preeti , Mishra Niharika , Khera Sanjeev , Kumar Rajiv
Published: November 2024

Mycosis fungoides (MF) is the most common type of cutaneous T-cell lymphoma in adults. However, it is rare in middle childhood. Such cases usually present with hypopigmented patches that may mimic common childhood dermatoses, thereby causing a delay in the diagnosis. Sezary syndrome is a rare and aggressive leukaemic variant of cutaneous lymphoma. We report a patient in middle childhood who presented with recurring non-specific folliculotropic manifestations. The final diagnosis of MF was arrived at after excluding all other possible dermatoses. Within a few months of skin manifestations, our index child was found to have blood involvement with similar clonal T-lymphoid cells. Such rapid development of Sezary syndrome within months of cutaneous presentation has never been described. There are no established treatment guidelines for the same in paediatric population. The patient underwent a matched sibling allogeneic transplant after a course of topical steroids and skin electron beam therapy.
Bilateral forearm compartment syndrome in a patient with recently diagnosed chronic myeloid leukaemia
Authors: Quinn Kate Rebecca , Defty-Wallace Paul , Hourston George Joseph Michael , Crosby Jonathan
Published: November 2024

Compartment syndrome is a limb-threatening surgical emergency that typically occurs unilaterally in the lower leg after trauma. It often occurs within hours of injury but can occur up to 48 hours or even several days later. We report the case of a male patient in his late 70s presenting with subacute, atraumatic, bilateral forearm compartment syndrome. The patient had commenced treatment for newly diagnosed chronic myeloid leukaemia and had in addition recently started a course of rivaroxaban for suspected deep venous thrombosis 3 weeks prior. The patient presented with bilateral upper limb swelling, skin discolouration, progressive pain and dysfunction. Emergency bilateral multicompartmental forearm fasciotomy was performed for limb preservation.
Optimising digital clinical consultations in maternity care: a realist review and implementation principles
Authors: Evans Catrin , Clancy Georgia , Evans Kerry , Booth Andrew , Nazmeen Benash , Sunney Candice , Clowes Mark , Jones Nia , Timmons Stephen , Spiby Helen
Published: November 2024

Objectives

The COVID-19 pandemic has led to increased use of digital clinical consultations (phone or video calls) within UK maternity services. This project aimed to review the evidence on digital clinical consultations in maternity systems to illuminate how, for whom and in what contexts, they can be used to support safe, personalised and equitable care.

Design

A realist synthesis, drawing on diverse sources of evidence (2010–present) from OECD countries, alongside insights from knowledge user groups (representing healthcare providers and service users).

Methods

The review used three analytical processes (induction, abduction and retroduction) within three iterative stages (development of initial programme theories; evidence retrieval and synthesis; validation and refinement of the programme theories).

Results

Ninety-three evidence sources were included in the final synthesis. Fifteen programme theories were developed showing that digital clinical consultations involve different mechanisms operating across five key contexts: the organisation, healthcare providers, the clinical relationship, the reason for consultation and women. The review suggests that digital clinical consultations can be effective and acceptable to stakeholders if there is access to appropriate infrastructure/digital resources and if implementation is able to ensure personalisation, informed choice, professional autonomy and relationship-focused connections. The review found relatively less evidence in relation to safety and equity.

Conclusions

Due to the complexity of maternity systems, there can be ‘no one-size fits all’ approach to digital clinical consultations. Nonetheless, the review distills four ‘CORE’ implementation principles: C—creating the right environment, infrastructure and support for staff; O—optimising consultations to be responsive, flexible and personalised to different needs and preferences; R—recognising the importance of access and inclusion; and E—enabling quality and safety through relationship-focused connections. Service innovation and research are needed to operationalise, explore and evaluate these principles, particularly in relation to safety and equity.

PROSPERO registration number

CRD42021288702.
Assessing the impact of COVID-19 on HIV care cascade for people living with HIV in Ethiopia: a retrospective longitudinal study
Authors: Amhare Abebe Feyissa , Shen Mingwang , Zou Zhuoru , Xia Ruyi , Han Jing , Gao Liangmin , Zhang Lei
Published: November 2024

Objective

The study aimed to investigate the impact of COVID-19 on the cascade of HIV care for people living with HIV (PLHIV) in Ethiopia.

Design

A retrospective longitudinal study.

Setting

The study was conducted in North Showa Zone, Ethiopia, from pre-COVID-19 (January 2018–December 2019) and during COVID-19 (January 2020–December 2021).

Participants

We identified 61901 records from 3925 PLHIV, of which 23 848 were recorded during the pandemic.

Main outcome measure

We investigated indicators from four stages of the HIV care cascade, including HIV screening and diagnosis, HIV care, HIV treatment and HIV disease progression, according to a WHO framework. The indicator changes were assessed with incidence rate ratios (IRRs).

Results

For HIV screening and diagnosis, the monthly number of HIV tests experienced a 46% decline from 2520 to 1361 since the pandemic (IRR 0.553; 95% CI 0.546 to 0.561). For HIV care, the monthly number of consultations was reduced by 49.6% (from 1582 to 798) since the pandemic (IRR 0.591; 95% CI 0.581 to 0.601). Similarly, the monthly number of viral load tests was reduced by 42.8% (IRR 0.614; 95% CI 0.581 to 0.650). For HIV treatment, the number of antiretroviral therapy (ART) initiations was reduced by 27.8% and the number of ART adherence by 52.5% since the pandemic. For HIV disease progression, the monthly number of PLHIV achieving viral suppression was reduced by 61.6%, while HIV-related deaths doubled during the pandemic.

Conclusion

The study highlights pandemic-induced disruptions in the cascade of care for PLHIV. Targeted interventions are necessary to protect PLHIV in public health emergencies.
Predictive factors associated with Bile culture positivity And phenotypiCal antIbiogram resistance patterns in patients taken to LaparOscopic cholecystectomy (BACILO): protocol for a prospective observational cohort study and development of a prognostic prediction model
Authors: Ramírez-Giraldo Camilo , Rodriguez Barbosa Carlos , Isaza-Restrepo Andrés , Avendaño-Morales Violeta , Rojas-López Susana , Van-Londoño Isabella
Published: November 2024

Introduction

Bile fluid is aseptic under normal conditions; however, in the presence of cholecystitis, its susceptibility to bacterial colonisation varies, with reported rates of 20%–70% of cases. This process is referred to as bactibilia and/or bacteriobilia and can be considered a secondary complication of biliary stasis and cholecystitis in general. In the management of acute cholecystitis, the antibiotic regimen should be prescribed based on the presumed pathogens involved, taking into consideration the risk factors for resistance patterns according to demographics and local exposure. The aim of this study is to determine the predictive factors for bile culture positivity and antibiotic resistance in patients who underwent laparoscopic cholecystectomy in the Méderi Hospital Network. We hope to develop a predictive model that allows us to better guide antibiotic therapy.

Methods and analysis

This is a prospective observational cohort study with prognostic prediction model. Patients who will undergo laparoscopic cholecystectomy and have bile cultures taken in the Méderi Hospital Network during the study period will be included. The dependent variables will be positive bile culture and antibiotic resistance, and the predictive variables will be age, presence of diabetes, diagnosis of choledocholithiasis, diagnosis of cholecystitis and severity of cholecystitis according to the Tokyo criteria. The minimum sample size has been calculated at 703 patients. Follow-up will continue until a control appointment 15 days after the procedure. The primary outcomes are bile culture positivity and phenotypical antibiogram resistance. For each outcome, a multivariate logistic regression will be performed using frequentist and Bayesian prediction techniques.

Ethics and dissemination

This study was approved by the Méderi network research department committee (CIMED) and by Universidad del Rosario’s Research Ethics Committee (CEI-UR; DVO005 2555-CV1837). Written informed consent is required for participation. The results will be disseminated through the submission of an academic article to a high-impact scientific journal, presentations at academic conferences, and sharing with our institution's faculty to inform antimicrobial therapy management based on local epidemiological data.

Trial registration number

NCT06314399.
Sri Lanka Child Growth Cohort (SLCGC): a population-based study on growth faltering of children
Authors: Wickramasinghe Vithanage Pujitha , Liyanage Guwani , De Silva Weliange Shreenika , Walpita Yasaswi Niranjala , Siriwardena Indika , Partheepan Kunarathinam , Yogeswaran Suganya , Rowel Dhammica , Daniel Abner , Jayawickrama Hiranya Senani , Senarath Upul
Published: November 2024

Purpose

This paper aims to describe the study design and baseline characteristics of the Sri Lanka Child Growth Cohort (SLCGC), which was established to assess the timing, pattern and determinants of growth faltering in infants and young children in Sri Lanka.

Participants

A retrospective cohort study was conducted among term-born babies (≥37-week gestation), currently aged between 12 and 24 months. A sample of 1875 mother–child pairs were recruited using two-stage stratified cluster sampling method. Data on sociodemographic characteristics, pregnancy care, feeding practices, childhood illnesses and home risk factors were collected through direct interviews with the caregivers. Pregnancy-related data were obtained from the pregnancy record. Birth weight, serial weight and length records and growth pattern were extracted from the Child Health and Development Record. Current weight and length of the children were measured directly.

Findings to date

The SLCGC serves as a comprehensive cohort study with a countrywide distribution in Sri Lanka, covering the three main residential sectors, namely the urban, rural and estate sectors in equal proportions. The majority of mothers were housewives (76.8%) and aged <35 years (77.9%). The proportions achieved secondary education in mothers and fathers were 69.0% and 63.7%, respectively. Approximately 30% of mothers were overweight or obese, while 15% were underweight on entry to antenatal care. Of the children, 49.2% were girls, 42.5% were the first-born children in their family and 34.2% were born by caesarean section. Mean birth weight was 2917 g (SD 0.406), with the proportion of low birth weight (less than 2500 g) being 13%.

Future plans

This data enables investigation of the effects of single exposures on child growth, as well as, more complex epidemiological analyses on multiple simultaneous and time-varying exposures. Data will be available for researchers for further analysis. The next wave of assessment is expected to be done after 12 months.
Analytical modelling techniques for enhancing tacrolimus dosing in solid organ transplantation: a systematic review protocol
Authors: Amooei Elmira , Buh Amos , Klamrowski Martin M , Shorr Risa , McCudden Christopher R , Green James R , Rashidi Babak , Sood Manish M , Hoar Stephanie , Akbari Ayub , Hundemer Gregory L , Klein Ran
Published: November 2024

Introduction

Tacrolimus is an immunosuppressant commonly administered in transplant recipients. Given its narrow therapeutic range and susceptibility to various influencing variables, determining its optimal dosage is challenging. This systematic review seeks to identify effective analytical modelling techniques and methods for optimal tacrolimus dose prediction in solid transplant recipients.

Methods and analysis

This review will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. The study will review the literature published from database inception to 11 March 2024, that assesses predictive models of tacrolimus dosing through analytical modelling techniques. We will include both randomised and non-randomised, as well as cross-sectional, qualitative and before-and-after studies and will perform our searches in four main databases—Ovid/MEDLINE, PubMed/MEDLINE, Scopus, Embase and Web of Science, and search engines including Centers for Disease Control (CDC) and Google Scholar. Papers that are not published in English or French are excluded from this study. A narrative synthesis and meta-analysis will be done if the extracted information permits such analysis. Conference abstracts will be ignored unless they are recent (published within 2 years of the search date).

Ethics and dissemination

Ethics clearance is not required for this study as no primary data will be collected. The completed manuscript will be published, and the results of the study will be presented at conferences.

Study registration

International Prospective Register of Systematic Reviews (PROSPERO), CRD42024537212.
Central venous catheter insertion profile and complications among neonates in Saudi Arabia: a cross-sectional study
Authors: Elabbasy Ahmed , Alkorbi Haifa Abdullah , Padua Ilene , Abuharb Abdullah Ibrahim , Alshedookhi Amjad Ahmad , Al-Shehri Hassan
Published: November 2024

Objectives

To compare complications in neonates who had umbilical venous catheter (UVC) versus peripherally inserted central catheter (PICC), percentage of non-elective removal of central catheters, and to compare complications of PICC in the upper limb compared with the lower limb.

Design

A prospective cross-sectional cohort study.

Setting

Neonatal intensive care unit (NICU) in Prince Sultan Military Medical City in Riyadh, Saudi Arabia.

Participants

All infants who are admitted to the unit requiring central catheter insertion were included in the study.

Primary outcome measure

Complications of central catheters in infants admitted to the NICU.

Results

A total of 415 central catheters were involved in this study (206 UVCs and 209 PICCs (85 in the lower limb, 99 in the upper limb and 25 in the head and neck). The median birth weight of the neonates was 1470 grams (1000–2215). Low birth weight was the most common reason for central catheter insertion, which accounted for 59.8%. Neonatologists were the main insertor for the majority of the cases. The median dwell days for the study sample were 11.00 (7.00–16.50) days. Complications were more common across PICC cases compared with UVC cases (p=0.001). There was non-elective removal of PICC (32.1%) compared with UVC (22.8%) (p=0.035). Phlebitis, occlusion, local infiltrate and leakage were more common in PICC compared with UVC (p<0.05). However, malposition was more commonly associated with the use of UVC (mainly to the liver) (p<0.01). Central line-associated bloodstream infection (CLABSI) rate in 1000.00 dwell days was higher in the upper limb 4.6 compared with the lower limb 2.72 but was not statistically significant (p=0.63), and there was no statistically significant difference in the proportion of other complications between the upper limb and the lower limb (p>0.05).

Conclusion

Close monitoring during extended dwell times is crucial. Our findings underscore the importance of raising awareness of CLABSI risk factors and adhering to best practices for central catheter maintenance. Healthcare professionals should be vigilant about the differences in complication rates between PICC and UVC, tailoring their approach accordingly.
Patients’ experiences with the application of medical adhesives to the skin: a qualitative systematic review
Authors: Hofman Hannelore , Duljic Tanja , Johansson Sara , Kottner Jan , Kinnaer Lise-Marie , Beeckman Dimitri , Eriksson Mats
Published: November 2024

Objectives

Medical adhesives provide securement of medical devices, facilitate skin protection and allow non-invasive monitoring. Application and removal of medical adhesives can result in pain, dermatitis, trauma or other skin lesions. Understanding patients’ experiences when subjected to medical adhesives will contribute to the improvement of clinical routines and the development and improvement of new adhesive technologies. A qualitative systematic review was conducted to identify patients’ experiences with the application of medical adhesives to the skin.

Design

Qualitative systematic review.

Data sources

CINAHL, EMBASE, MEDLINE and PsycINFO were systematically searched for records published between January 2012 and March 2024. Reference lists of systematic reviews and included articles were reviewed.

Eligibility criteria

Studies published in Danish, Dutch, English, German, Norwegian and Swedish that collected qualitative data on the experience of patients with the application of medical adhesives to the skin were considered. There were no restrictions regarding age, gender or setting.

Data extraction and synthesis

Study selection, data extraction and quality appraisal were independently conducted by two reviewers. The methodological quality of the studies under consideration was assessed using the Joanna Briggs Institute Critical Appraisal Tool for Qualitative Research. The extracted data were synthesised using meta-aggregation.

Results

Nine studies describing patients’ experiences were included. The included studies only reflected experiences with wound dressings. Meta-aggregation of the extracted findings resulted in seven categories that were further synthesised into two synthesised findings: ‘strategies to alleviate pain during dressing changes’ and ‘dressing construction and characteristics’. The synthesised findings illustrate that patients experience pain during dressing change and removal and employ various strategies to alleviate this pain.

Conclusions

Patients experience pain and discomfort when dressings are changed or removed. Future research should focus on enhancing both routines and technologies, with a particular emphasis on advancing skin-friendly adhesives to reduce unwanted side effects.

PROSPERO registration number

CRD42023457711.
Factors affecting outcome of acquired comitant esotropia with restricted use of digital devices: ACEDD Study 3
Authors: Nishikawa Noriko , Iimori Hirohito , Kinouchi Reiko , Nishina Sachiko , Yoshida Tomoyo , Hikoya Akiko , Komori Miwa , Hieda Osamu , Goseki Toshiaki , Mori Takafumi , Morimoto Takeshi , Negishi Takashi , Shimizu Tamami , Shimizu Yukiko , Hayashi Shion , Sugiyama Yoshiko , Yokoyama Yoshimi , Kimura Akiko , Suzuki Hiroko , Suzuki Sadao , Azuma Noriyuki , Sato Miho
Published: November 2024

Objective

The objective of this study is to investigate factors associated with outcomes after 3 months of instructed usage of hand-held digital devices (DD) in patients with acquired comitant esotropia (ACE).

Methods and analysis

This prospective multicentre observational study included patients with ACE, aged 5–35 years, who used DD within 1 year of onset and were followed up for clinical findings and instructed use of DD. The outcomes were classified into four groups: cured, improved, unchanged and worsened. After the analysis of group differences in the clinical and DD use-related factors by univariate analysis, we used ordinal logistic regression models to identify factors associated with favourable outcomes.

Results

Of 156 patients (mean age (SD): 16.4 (7.4) years), 10 (6%), 58 (37%), 67 (43%) and 21 (14%) were classified into the cured, improved, unchanged, and worsened, respectively. In the univariate analysis, consultation within 3 months of onset, small-angle strabismus at distance and good stereoacuity were associated with good outcomes. Ordinal logistic regression analysis on adjusting for age with stereoacuity or successful DD-use time halving showed that small-angle strabismus at distance (OR: 1.02, 95% CI 1.00 to 1.03, p=0.023), good stereoacuity (OR: 1.31; 95% CI 1.10 to 1.56; p=0.003) and successful halving of DD-use time (OR: 0.63; 95% CI 0.43 to 0.92; p=0.016) influenced favourable outcomes.

Conclusion

Patients with small-angle esotropia, good stereoacuity on consultation and success in halving DD-use time had a higher chance of recovery through instructional DD usage. Further studies using objectively measurable systems are needed to ensure the accuracy of DD-use time.