bluuebunny/crossref_metadata_2025 huggingface dataset:
Comprehensive investigation of vortex-induced vibration and aerodynamic forces characteristics in tandem rectangular sections
Authors: Duan Qingsong , Zhang Hong , Ran Xinping , Chen Haonan , Shang Jingmiao
Published: January 2025

The aerodynamic interference effects between tandem structures are significant and can adversely affect both the wind-induced vibration characteristics and the aerodynamic performance. To investigate these effects, wind tunnel tests and numerical analyses were performed on chamfered and non-chamfered rectangular sections. Different spacings 2.9B–5.0B (B represents section width) were considered. Wind tunnel tests evaluated the vortex-induced vibrations (VIV) amplitude and wind speed range. Numerical analyses examined the aerodynamic characteristics and flow structure. It indicates that chamfered corners can enhance the VIV performance of a single structure. While the maximum VIV amplitude in the upstream column with chamfered corners, at spacing of 2.9B, increases by 288% than that of a single section, and gradually decreases as the spacing increases. The maximum VIV amplitudes of upstream rectangular section are slightly increased. For downstream section, the maximum VIV amplitude is much smaller than that of a single section. The mean drag coefficient of downstream cylinder consistently remains lower than that of upstream section, although it slightly increases with larger spacing. Chamfered corners cause upstream wake vortices to contract and downstream wake vortices to elongate along the flow direction. At spacing 2.9B, vortices shed from the upstream section just impact the windward side of downstream section. Compared to the upstream section, the vortex core center of the downstream column section is closer to its leeward surface, and the recirculation length is shorter than that of the upstream section. The research findings can serve as a reference for wind-resistant design of similar structures.
Hydrodynamic performance of undulating fin in oscillating mode
Authors: Li Guanghao , Ma Penglei , Li Gongbo , Fang Xin , Liu Guijie
Published: January 2025

The undulating fin exhibits two distinct motion modes: undulation and oscillation. However, the hydrodynamic performance during oscillatory motion has been rarely reported. In this study, numerical simulations were conducted to investigate the effects of factors such as the undulating angle, oscillation angle, and oscillation frequency on the hydrodynamic performance of the undulating fin during oscillatory motion. The mechanism of undulating fin oscillation was elucidated through flow field analysis. The results demonstrate that the undulating fin achieves unilateral movement during a single oscillation cycle. The hydrodynamic performance in the X-direction exhibits non-sinusoidal characteristics and shows a positive correlation with the undulating angle. In contrast, the hydrodynamic performance in the Y-direction correlates positively with both the oscillation angle and frequency. The hydrodynamic performance in the Z-direction is closely related to the vortex shedding position. Positive thrust is generated when the vortex sheds from the outer side of the undulating fin. This study provides novel insights and motion strategies for underwater locomotion of robots equipped with undulating fins.
The population dynamics of clustered consumer–resource spatial patterns: Insights from the demographics of a Turing mechanism
Authors: Hajian-Forooshani Zachary , Rivera-Salinas Iris Saraeny , Perfecto Ivette , Vandermeer John
Published: January 2025

In ecology, Alan Turing’s proposed activation–inhibition mechanism has been abstracted as corresponding to several ecological interaction types to explain pattern formation in ecosystems. Consumer–resource interactions have strong theoretical arguments linking them to both the Turing mechanism and pattern formation, but there is little empirical support to demonstrate these claims. Here, we connect several lines of evidence to support the proposition that consumer–resource interactions can create empirically observed spatial patterns through a mechanism similar to Turing’s theory. We propose the existence of a fine-scale demographic spatial pattern (DSP), in which the youngest resources are located at the periphery and oldest in the center of clusters. We find evidence of a DSP in the spatially clustered distribution of arboreal ant nests, whose large-scale spatial patterning has previously been hypothesized to be driven by ant parasitoids. Through a combination of field surveys and analysis of demographic trends, we demonstrate how the DSP structures the interactions between the ant and its parasitoid. To explore the implications of DSP for consumer–resource pattern forming systems generally, we use a spatially explicit consumer–resource model to show how relative diffusion rates of the system shape multiscale spatial patterns that structure the demographic trends of the resource population in predictable ways. This work provides both empirical support for consumer–resource spatial patterns as well as a multiscale approach to understand their spatially explicit population dynamics.
An evolutionarily conserved cation channel tunes the sensitivity of gustatory neurons to ephaptic inhibition in
Drosophila
Authors: Lee MinHyuk , Kim Seon Yeong , Park Taeim , Yoon Sung-Eun , Kim Young-Joon , Joo Kyeung Min , Kwon Jae Young , Kim Kyuhyung , Kang KyeongJin
Published: January 2025

In ephaptic coupling, physically adjacent neurons influence one another’s activity via the electric fields they generate. To date, the molecular mechanisms that mediate and modulate ephaptic coupling’s effects remain poorly understood. Here, we show that the hyperpolarization-activated cyclic nucleotide–gated (HCN) channel lateralizes the potentially mutual ephaptic inhibition between
Drosophila
gustatory receptor neurons (GRNs). While sweet-sensing GRNs (sGRNs) engage in ephaptic suppression of the adjacent bitter-sensing GRNs (bGRNs), HCN expression in sGRNs enables them to resist ephaptic suppression from the bGRNs. This one-sided ephaptic inhibition confers sweetness dominance, facilitating ingestion of bitter-laced sweets. The role of fly HCN in this process can be replaced by human HCN2. Furthermore, unlike the mechanism in olfaction, gustatory ephaptic inhibition is independent of sensillum potential changes, suggesting that the compartmentalized arrangement of neighboring GRNs is dispensable for gustatory ephaptic inhibition. These findings indicate a role for the gating of ephaptic coding to ensure the intake of the essential nutrient despite bitter contaminants present in the feeding niche of
Drosophila
, and propose that studies in
Drosophila
gustation could reveal ephaptic principles conserved across diverse animals.
Plant BCL-DOMAIN HOMOLOG proteins play a conserved role in SWI/SNF complex stability
Authors: Candela-Ferre Joan , Pérez-Alemany Jaime , Diego-Martin Borja , Pandey Vijaya , Wohlschlegel James , Lozano-Juste Jorge , Gallego-Bartolomé Javier
Published: January 2025

The SWItch/Sucrose Non-Fermenting (SWI/SNF) complexes are evolutionarily conserved, ATP-dependent chromatin remodelers crucial for multiple nuclear functions in eukaryotes. Recently, plant BCL-DOMAIN HOMOLOG (BDH) proteins were identified as shared subunits of all plant SWI/SNF complexes, significantly impacting chromatin accessibility and various developmental processes in Arabidopsis. In this study, we performed a comprehensive characterization of
bdh
mutants, revealing the role of BDH in hypocotyl cell elongation. Through detailed analysis of BDH domains, we identified a plant-specific N-terminal domain that facilitates the interaction between BDH and the rest of the complex. Additionally, we uncovered the critical role of the BDH β-hairpin domain, which is phylogenetically related to mammalian BCL7 SWI/SNF subunits. While phylogenetic analyses did not identify BDH/BCL7 orthologs in fungi, structure prediction modeling demonstrated strong similarities between the SWI/SNF catalytic modules of plants, animals, and fungi and revealed the yeast Rtt102 protein as a structural homolog of BDH and BCL7. This finding is supported by the ability of Rtt102 to interact with the Arabidopsis catalytic module subunit ARP7 and partially rescue the
bdh
mutant phenotypes. Further experiments revealed that BDH promotes the stability of the ARP4-ARP7 heterodimer, leading to the partial destabilization of ARP4 in the SWI/SNF complexes. In summary, our study unveils the molecular function of BDH proteins in plant SWI/SNF complexes and suggests that β-hairpin-containing proteins are evolutionarily conserved subunits crucial for ARP heterodimer stability and SWI/SNF activity across eukaryotes.
Analysis of electron spectra dynamics in a moving periodical ponderomotive potential
Authors: Kuchař Marek , Moriová Kamila , Kozák Martin
Published: January 2025

The interaction between freely propagating electrons and light waves is typically described using an approximation in which we assume that the electron’s velocity nearly does not change during the interaction. In this article we analytically describe the dynamics of electrons in an interaction potential generated by an optical beat wave beyond this regime and find a structure of sharp electron distribution peaks that periodically alternate in the energy/momentum spectrum. In classical description we analytically solve the nonlinear equation of motion, which is an analogy to mathematical pendulum. While addressing the problem using quantum mechanics we first use parabolic approximation of the interaction potential and then we also study the evolution of electron wavepacket in an infinite periodical potential. Using numerical simulations we show the classical and quantum evolution of the electron spectra during the interaction for different conditions and experimental settings.
Quantum dot distributed feedback laser grown on silicon with laterally coupled gratings
Authors: Yang Bo , Han Dong , Wei Wenqi , Cui Xiangru , Wang Zihao , Wang Ting , Zhang Jianjun
Published: January 2025

Direct epitaxy of quantum dot (QD) lasers on silicon is considered the holy grail of integrated silicon photonics. Various InAs/GaAs QD lasers grown directly on silicon substrates have been demonstrated but there has been limited research on single-longitudinal-mode lasers on silicon. Here, to avoid any regrowth procedures, distributed feedback (DFB) QD lasers on silicon are fabricated with lateral coupled (LC) gratings via a simplified fabrication process. The LC-DFB laser has a maximum laser power of 4.2 mW and threshold current of 80 mA under continuous-wave current mode at room temperature. Under an injection current of 110 mA, the side mode suppression ratio reaches 50 dB at room temperature. The relative intensity noise of the laser is measured as −135 dB Hz–1, with a corresponding optical linewidth of 3.5 MHz.
Explicit construction of quasi-periodic finitely differentiable Schrödinger operators with Cantor spectrum
Authors: He Jiawei , Cheng Hongyu
Published: January 2025

In this paper, we construct finitely differentiable quasi-periodic Schrödinger operators with Cantor spectrum and prove that the sizes of the spectral gaps exhibit polynomial asymptotics.
Multi-label segmentation of carpal bones in MRI using expansion transfer learning
Authors: Raith Stefan , Deitermann Matthias , Pankert Tobias , Li Jianzhang , Modabber Ali , Hölzle Frank , Hildebrand Frank , Eschweiler Jörg
Published: January 2025

Objective. The purpose of this study was to develop a robust deep learning approach trained with a small in-vivo MRI dataset for multi-label segmentation of all eight carpal bones for therapy planning and wrist dynamic analysis. Approach. A small dataset of 15 3.0-T MRI scans from five health subjects was employed within this study. The MRI data was variable with respect to the field of view (FOV), wide range of image intensity, and joint pose. A two-stage segmentation pipeline using modified 3D U-Net was proposed. In the first stage, a novel architecture, introduced as expansion transfer learning (ETL), cascades the use of a focused region of interest (ROI) cropped around ground truth for pretraining and a subsequent transfer by an expansion to the original FOV for a primary prediction. The bounding box around the ROI generated was utilized in the second stage for high-accuracy, labeled segmentations of eight carpal bones. Different metrics including dice similarity coefficient (DSC), average surface distance (ASD) and hausdorff distance (HD) were used to evaluate performance between proposed and four state-of-the-art approaches. Main results. With an average DSC of 87.8 %, an ASD of 0.46 mm, an average HD of 2.42 mm in all datasets (96.1 %, 0.16 mm, 1.38 mm in 12 datasets after exclusion criteria, respectively), the proposed approach showed an overall strongest performance than comparisons. Significance. To our best knowledge, this is the first CNN-based multi-label segmentation approach for MRI human carpal bones. The ETL introduced in this work improved the ability to localize a small ROI in a large FOV. Overall, the interplay of a two-stage approach and ETL culminated in convincingly accurate segmentation scores despite a very small amount of image data.
First-principles study of electronic and magnetic properties of self-intercalated van der Waals magnet Cr3Ge2Te6
Authors: Li Jia-wan , Zhao Shi-Bo , Zhuang Lin , Hou Yusheng
Published: January 2025

Self-intercalated van der Waals magnets, characterized by self-intercalating native atoms into van der Waals layered structures with intrinsic magnetism, exhibit a variety of novel physical properties. Here, using first-principles calculations and Monte Carlo simulations, we report a self-intercalated van der Waals ferromagnet, Cr3Ge2Te6, which has a high Curie temperature of 492 K. We find that Cr3Ge2Te6 is nearly half-metallic with a spin polarization reaching up to 90.9%. Due to the ferromagnetism and strong spin-orbit coupling effect in Cr3Ge2Te6, a large anomalous Hall conductivity of 138 Ω-1
cm
-1 and 305 Ω-1
cm
-1 can be realized when its magnetization is along its magnetic easy axis and hard axis, respectively. By doping electrons (holes) into Cr3Ge2Te6, these anomalous Hall conductivities can be increased up to 318 Ω-1
cm
-1 (648 Ω-1
cm
-1). Interestingly, a 5-layer Cr3Ge2Te6 thin film retains the room-temperature ferromagnetism with a higher spin polarization and larger anomalous Hall conductivity. Our work demonstrates that Cr3Ge2Te6 is a novel room-temperature self-intercalated ferromagnet with high spin polarization and large anomalous Hall conductivity, offering great opportunities for designing nano-scale electronic devices.
Measure-and-remeasure as an economically feasible approach to crediting soil organic carbon at scale
Authors: Potash Eric , Bradford Mark A , Oldfield Emily E , Guan Kaiyu
Published: January 2025

Agricultural carbon crediting predominantly relies on process-based biogeochemical models to estimate accrual of soil organic carbon stock (SOC). We investigate the conditions under which it may be economical to estimate SOC accrual by measuring and remeasuring SOC, which relies on fewer assumptions than modeling. We analyze multi-field measure-and-remeasure SOC projects with two key features: first, practice assignment is randomized to compare the effect of a treatment (e.g. no tillage) to a control (e.g. conventional tillage); second, a random subset of fields is sampled (two stage cluster sampling) to cost-effectively measure SOC changes. We use statistical modeling to characterize the estimated treatment effect, accounting for within-field and between-field variability in SOC change, as well as measurement error. We then use these statistics to evaluate how prices for measurement, treatment, and carbon credits influence the economics of measure-and-remeasure projects. We specifically investigate the potential advantages of larger spatial scale (number of fields) and temporal scale (years before remeasurement). We find economies of both spatial and temporal scale so that projects with thousands of fields, with only about 10% of fields measured for SOC change, are likely to yield a competitive return on investment in five years if the treatment effects found in the research literature can be achieved commercially. Our analysis suggests that measure-and-remeasure can be cost effective in both market and non-market SOC projects at scale. Moreover, measure-and-remeasure projects provide valuable data for independent validation on commercial farms of the accrual rates estimated by biogeochemical models using field trials. We provide next steps and software for researchers, credit registries, and project developers to move forward with measure-and-remeasure SOC projects.
Fundamental operating regimes, hyper-parameter fine-tuning and glassiness: towards an interpretable replica-theory for trained restricted Boltzmann machines
Authors: Fachechi Alberto , Agliari Elena , Aquaro Miriam , Coolen Anthony , Mulder Menno
Published: January 2025

We consider restricted Boltzmann machines with a binary visible layer and a Gaussian hidden layer trained by an unlabelled dataset composed of noisy realizations of a single ground pattern. We develop a statistical mechanics framework to describe the network generative capabilities, by exploiting the replica trick and assuming self-averaging of the underlying order parameters (i.e. replica symmetry). In particular, we outline the effective control parameters (e.g. the relative number of weights to be trained, the regularization parameter), whose tuning can yield qualitatively-different operative regimes. Further, we provide analytical and numerical evidence for the existence of a sub-region in the space of the hyperparameters where replica-symmetry breaking occurs.
Evaluating the effectiveness of cost-minimal planning of decarbonized electricity systems in reducing life cycle greenhouse gas emissions
Authors: Tarroja Brian , Mulvaney Dustin , Peer Rebecca , Grubert Emily
Published: January 2025

The decarbonization of regional electricity systems is a critical enabler of broader economy-wide decarbonization strategies and has motivated robust research on how to decarbonize electricity systems at minimum monetary cost. Since these efforts often focus on the operation of electricity systems, however, they do not account for emissions of the full life cycle associated with different resources. Different resource mixes can achieve a similar level of apparent decarbonization through operational emissions, while achieving very different levels of life cycle greenhouse gas (GHG) emissions reductions. To explore these differences, we model the expansion of the California electricity system from 2030 to 2045 using a simplified electricity dispatch model to investigate how the planning of future electricity systems may differ between prioritizing minimum cost versus minimum life cycle GHG emissions under a common target for operational GHG reductions. We find that explicitly planning for minimum life cycle GHG emissions yields an additional 1.6%–2.0% reduction in annual life cycle GHG emissions at a cost penalty of 5.1%–6.9% and that electricity resource mixes that minimize life cycle GHG emissions tend to favor high capacity factor zero-carbon resources and long-duration storage compared to a minimum cost approach. Comparatively, we find that aggressive supply chain decarbonization of generation and storage technologies reduces life cycle GHG emissions of electricity supplies by 3.0% to 14% and combining both increases these reductions to 5.0% to 16%. Further, we find that applying a carbon tax to minimum cost-based capacity expansion can incentivize planning to account for life cycle GHG emissions. Our results indicate that a planning approach focused on minimizing life cycle GHG emissions may not be palatable, but significant reductions in life cycle emissions can be realized through conventional mechanisms like carbon taxes, import standards, and targeted supply chain decarbonization.
O1 Using Machine Learning to predict the Severity of Acute Pancreatitis: A Systematic Review
Authors: Nadeem Zain , Yau Christopher , Chan Anthony
Published: January 2025

Background

Acute pancreatitis (AP) is an inflammatory condition of the pancreas where, in its severe form, has a mortality of up to 30%. The severity of AP is traditionally predicted with using static scoring systems such as Ranson and APACHE II based on clinical observations and/or blood test results. The Revised Atlanta Classification of AP, however, include the assessment of local complications such as peripancreatic fluid collections and necrosis which can be more subjective and relies on human clinical or radiological judgement. The aim of this study is to review the literature and evaluate the potential role and effectiveness of machine learning (ML) in the stratification of AP severity.

Methods

A systematic review was conducted using PubMed with search terms including acute pancreatitis, severity and machine learning. The inclusion criteria selected studies describing the development and validation of ML models predicting AP severity and to those publishing sensitivity and specificity data.

Results

There were 97 articles identified which after applying the inclusion and exclusion criteria, 11 studies were included in the review. ML training datasets ranged from 265 to over 350,000 patients, with inputs varying from patient demographics, clinical observations and blood results as well as radiomic data. The highest sensitivity (96%) and specificity (98%) predictors for severe AP outperformed Ranson, APACHE II and BISAP scoring systems.

Conclusion

ML models display superior accuracy when compared to traditional scoring systems in predicting AP severity. Radiomic data from Computed Tomography images can increase the sensitivity and specific of predictive models.
eP5 Adherence of Diagnosis and Management of Acute Appendicitis in Adults to WSES Jerusalem Guidelines
Authors: Patel Aminah , Alwani Omneya , Alasmar Mohamed , Abdelrahman Asem
Published: January 2025

Aims

This audit aims to assess adherence to the guidelines on diagnosis and treatment of acute appendicitis published by the World Society of Emergency Surgery (WSES) part of their 2020 update of the WSES Jerusalem guidelines. The practical WSES algorithm was used to audit patients’ journey regarding how the diagnosis was made and what management this led to.

Method

A retrospective analysis was conducted on 92 adult patients who were referred to the emergency general surgical team at a university teaching hospital for query/suspected appendicitis, between December 2022 to February 2023. These patients’ risk was calculated using AAS (Adult Appendicitis Score), Alvarado and AIR (Appendicitis Inflammatory Response) scores and the guidelines were used to record what should be the next step based on the risk score. This was then compared to the actual management that took place.

Results

When reviewing the initial risk scores, 54 patients (59%) had the correct next step based on the algorithm. Majority of the patients (40%) had a CT scan of their abdomen and pelvis and 78% of these showed appendicitis. In total 35 patients had surgery, which included 86% that were appendicectomy and 97% of these confirmed appendicitis on histology. 5% of patients had diagnostic laparoscopy and only 20% of these confirmed appendicitis.

Conclusion

The WSES guidelines provide good guidance onto what the initial investigations should be and the management. In this audit just roughly 60% of patients were managed according to the guidelines, therefore there is room for further adherence.
eP16 Management and outcomes of small bowel obstruction- not just the “now” but what about the “next”
Authors: Inteti Kamalesh , Rashid Rahel , Babiker Mohammed , Magee Conor , Wilson Jeremy
Published: January 2025

Aim

Small bowel obstruction (SBO) is a common surgical emergency with wide inconsistency in management as evidenced by the National Audit on Small Bowel Obstruction (NASBO). We sought to assess our management in the light of the NASBO recommendations.

Methods

A prospective cohort study in a UK district general hospital of patients admitted with SBO from December 2023 to March 2024. Outcomes included demographics, laboratory parameters and pathway milestones. Data were retrieved through an electronic database and analyzed using descriptive statistical software in Excel.

Results

Forty patients with a median age of 75 years were included. Mechanical causes were found in 38 (95%) with adhesions leading the list with 21 (55%). CT was done in everyone while X-ray was in 75% of them. Non-operative management was successful in 24 (60%) patients while surgery was fruitful in 16 (40%). Water soluble oral contrast challenge (WSOC) was successful in 15 out of the 20 patients who received it. Nutrition team input was sought out in 19 (∼50%) patients, among them 12 (30%) required nutritional support.

Of note fifteen (37.5%) patients had a recurrent SBO with 12 (80%) of them operated in an emergency setting.

Conclusion

Non-operative management with WSOC has reported a success rate of 75%. This is encouraging- as is the utilization of nutritional assessment and input.

Recurrent SBO is associated with an increased need for surgical intervention. Patients with index SBO may need closer follow-up arrangements and attention should be on identifying interventions to prevent recurrent SBO.
eP21 Improving Fasting Times: Abdominal Ultrasound for Acute Gallbladder Pathology – a Quality Improvement Project
Authors: Buchanan Emily , Sefa Adwoa , Carswell Kirstin
Published: January 2025

Background/Aims

Patients with acute gallbladder pathology (AGP) spend long periods of time fasting for scans and procedures, causing discomfort and unfavourable outcomes with a lengthened period in a catabolic state. Regular nutrition aids healing and patient satisfaction in the perioperative period. We aim to meet the Royal College of Radiologists’ (RCRs’) recommended 4-6 hour fasting time through streamlining prioritisation of Ultrasound Abdomen (USS-A), preventing complications of fasting, improving patient safety and satisfaction.

Methods

Retrospective data was collected for one month from electronic patient records. Inclusion criteria was patients investigated for AGP with USS-A identified from a daily departmental ‘take’ list. Exclusion criteria was patients who underwent USS-A for indications other than AGP. Our intervention was two-fold – firstly, highlighting USS-A (investigating AGP) to Radiology Department by ‘hot GB’ in indication section of request form, flagging scan completion within 6 hours. Secondly, ‘red’ and ‘green’ signs above beds denoting sips of water or eating and drinking as tolerated, respectively, prompting communication between staff about intake status. Data was collected and analysed using Microsoft Excel and GraphPad Prism.

Results

Median fasting time of 16.95 hours and waiting time of 18.93 hours (n=40) improved to 9.22 hours fasting and 13.45 hours waiting (p=0.21 and p=0.27, respectively). 44% of scan requests had ‘hot GB’ documented as the indication, following implementation of the intervention (n=27).

Conclusions

Average fasting time improved significantly but still falls short of RCR recommendation. Future scope includes education to ensure requests include ‘hot GB’, and development of a national AGP pathway.
eP29 High Alvarado score is independently associated with appendicitis in children with inconclusive ultrasound
Authors: Soliman Ahmed Bahgat
Published: January 2025

Acute appendicitis (AA) is a challenging diagnosis in the paediatric population. It usually requires meticulous examination of clinical, laboratory and radiological data. In most studies, ultrasound (US) was found to be highly reliable and accurate for diagnosing paediatric appendicitis. However, an inconclusive US in children with right lower quadrant pain is likely to be challenging for the emergency physician.

We performed a retrospective investigation in a paediatric emergency unit from 1st January 2020 to 31st December 2023. All paediatric patients under 14 years of age with right lower quadrant pain and an inconclusive US were included. The Alvarado score, based on a combination of clinical and laboratory factors, was computed for all patients. The surgeon was free to decide whether or not to order a CT scan.

Our analysis showed that patients with proven appendicitis had higher WBC counts, CRP levels, and Alvarado scores. Thus, this analysis identified that children with Alvarado scores ≥ 7 were over 34 times more likely to have AA than those with Alvarado scores < 7, Leukocytosis > 15 x109/L, and CRP> 50 mg/l were also identified as independent predictors of AA in these children. Our study showed that the Alvarado score, potentially combined with laboratory data, is highly useful for diagnosing appendicitis in children with right lower quadrant abdominal pain and inconclusive US. These factors would make it possible not only to provide an accurate pre- operative diagnosis, but also to inform the patient and his/her family, and ultimately to spare the child from unnecessary radiation.
eP31 Safety of bowel anastomosis in emergency laparotomy
Authors: Claydon Oliver , Paduraru Mihai
Published: January 2025

Aims

Anastomotic leakage (AL) is a dreaded complication of surgical bowel anastomosis, associated with higher post-operative morbidity and mortality. Prevalence of AL varies from 1-19%, but is higher in the emergency setting due to risk factors including contamination, ionotrope use, shock and hypoalbuminemia. Consideration must be given to the safety of anastomosis vs stoma in this setting. Our objective was to perform a local audit of outcomes of bowel anastomoses formed during emergency laparotomy.

Methods

All cases of emergency laparotomy with bowel anastomosis performed at our hospital between 5/5/22 and 31/12/23 were retrospectively identified from hospital records. Enterotomy closure alone and patients <16 were excluded. Returns to theatre for post-operative complication were included. Details of pathology, anastomosis, and outcome were collected from medical notes.

Results

100 cases fitting criteria were identified. The most common pathologies requiring bowel resection were adhesional obstruction (26%), obstructing cancer (15%) and incarcerated hernia (10%). 69% of anastomoses were small bowel; 26% were ileo-colic. There were 9 Clavien-Dindo 3+ complications. There were 6 anastomotic leaks; 2 from small bowel anastomoses, which were both managed as controlled entero-cuteneous fistulas, and 4 from ileo-colic anastomoses, which were all returned to theatre for stoma. There was one mortality.

Conclusions

Our AL rate of 6% is comparable to reported leak rate of electively-formed anastomoses. Bowel anastomosis formed during emergency laparotomy is not inherently unsafe. The decision for anastomosis vs stoma should be made on an individual basis with the patient counselled pre-operatively if possible about the risk of leak.
eP32 Intestinal Obstruction: Case study on a different presentation of Systemic Amyloidosis
Authors: Nesnas Leen , Alabbasi Iea , Bunting David
Published: January 2025

Aim

This study aims to evaluate treatment strategies for acute presentations of systemic amyloidosis in the gastrointestinal tract. Systemic amyloidosis, identified by the extracellular deposition of β-sheet protein fibrils, often affects the GI tract, particularly in primary (AL) amyloidosis. GI amyloidosis can severely disrupt organ function, requiring prompt and effective treatment. This study focuses on optimizing the management of these acute GI manifestations.

Methods

66 year old female presented to ED, with 6 days abdominal pain, distention, vomiting, and not opening her bowels for one week. She had a background of amyloidosis secondary to multiple myeloma on medical treatment. CT scan showed the stomach and the majority of the small bowel are grossly distended with fluid. There appeared to be at least one transition point with faecalis loop of small bowel proximal to it. She then had an emergency laparotomy.

Results

Intraoperative findings showed abnormal, hardened fecal matter throughout the small bowel. An enterotomy was performed with manual evacuation of the bowel contents. Postoperatively, she required ICU support, intravenous fluids, and empirical antibiotics She had a post-operative ileus with high NG output. This was managed with prokinetic agents including erythromycin, metoclopramide, and prucalopride. She was discharged with home based TPN.

Conclusion

Management of GI amyloidosis varies by type and presentation, focusing on symptomatic relief and systemic treatment. Prokinetic agents are crucial for dysmotility, and severe cases may require parenteral nutrition. Surgical intervention is necessary for obstructions, uncontrolled haemorrhage, or ischemia. Early identification and appropriate management are essential for improved outcomes.
eP36 Quality improvement Project: Optimizing necrotizing fasciitis management; Evaluation and development of comprehensive guidelines for improved patient outcomes
Authors: Ansar Mehwish , Mustafai Muneeba , Kaur Smonica , Inteti Kamlesh , Magee Conor , Wilson Jeremy
Published: January 2025

Aims

The study was conducted to scrutinize the current approaches for management of necrotizing fasciitis (NF) at our centre and aimed to formulate evidence-based guidelines to optimize care, outcomes and reduce mortality. The primary objective was refining diagnosis, early surgical intervention, antibiotics protocol and multidisciplinary approach for comprehensive management.

Methods

A comprehensive retrospective three-year review on 16 patients, diagnosed with NF was conducted. Data were extracted on the site of infection, multidisciplinary involvement, timing and frequency of surgeries, antibiotic regimen, and outcomes. This analysis provide insight to develop the management guidelines to enhance the quality of care.

Results

In six (37.5%) patients the infection site was premium. Triple assessment by surgery, anaesthesia and critical care was received by ten (62%) patients and ten patients required intensive care admission, reflecting multidisciplinary collaboration. Inconsistencies was observed in antibiotics, mostly clindamycin and Tazocin were administered, initiated within 5 hours of diagnosis. Ten (62%) had surgical intervention, mostly within 12 hours. Multiple debridement ranging from 1 to 9 were performed in eight (50%) patients. Two patients were referred to plastic surgery. 100% cultures have shown polymicrobial growth. Mortality rate was 20% among those who had surgery. The absence of standardized protocol and variability in management in different trust was highlighted in this study.

Conclusion

The study highlights the need for standardized, evidence-base guidelines for management of NF. The observed variability in patients care and outcome suggest a multicentre audit, to formulate comprehensive guidelines to manage this life-threatening condition to standardized care and enhance outcomes.
eP41 CORES model scoring system for predicting post-operative mortality in patients undergoing Emergency Laparotomy and its comparison with APACHE II: An observational study
Authors: Kumar Navin , Panga Harshavardhan , Singh Sudhir Kumar , Basu Somprakas
Published: January 2025

Aim

To determine the effectiveness of the CORES model in predicting post-operative in-hospital and 30-day mortality in patients undergoing emergency laparotomy.

Methods

The CORES and APACHE-II scoring were done in 211 patients aged> 18 years undergoing emergency laparotomy, and both scores were compared, with calculating mortality rate being the primary objective. Abdominal trauma, pregnancy and ASA grade V were excluded. CORES was constructed using a regression model based on the presence or absence of Japan coma scale >30, ASA class III, ASA class IV, WBC <2500 cells/ μL, Platelet count <150000 / >300000 cells/ μL and blood urea nitrogen >/= 40mg/dL.

Results

The CORES in-hospital and 30-day mortality prediction score was marginally less than the APACHE II (Table 1& 2)Table 1:APACHE II versus CORES in-hospital mortality scorePredictorAUROC95% CIpSn%Sp%PPV%NPV%DA%ORAPACHE II0.9010.85-0.94<0.00170937889871.42CORES0.8600.80-0.91<0.00181735391752.35Table 2:APACHE II versus CORES 30-day mortality scorePredictorAUROC95% CIpSn%Sp%PPV%NPV%DA%ORAPACHE II0.8850.834-0.937<0.00170927490861.42CORES0.8670.808-0.926<0.00176876691842.67AUROC: Area under ROC curve; CI: Confidence interval; Sn: Sensitivity; Sp: Specificity; PPV: Positive predictive value; NPV: Negative predictive value; DA: Diagnostic Accuracy.

Conclusion

CORES accurately predicting post-operative mortality. However, CORES was less effective than APACHE II in calculating in-hospital mortality but equally effective in predicting 30-day postoperative mortality.
eP48 Multi-cycle audit on antibiotic duration and stepdown following laparotomy
Authors: Lonergan Rebecca Murphy , Singh Anaida , Kalidindi Venugopala
Published: January 2025

Aims

To audit adherence to local guidelines on antibiotic stewardship in patients who underwent laparotomy, particularly, duration of antibiotics following definitive surgery/source control To increase antibiotic stewardship by reducing duration of antibiotic course and promoting consideration of early stepdown of antibiotics where clinically appropriate in patients following laparotomy

Methods

Data were reviewed for all adult general surgery patients who underwent laparotomy over a 4-month period in late 2023. Patients were excluded if there were incomplete or unavailable documentation relating to their operation or post-operative care. Data were extracted relating to patient demographics, type of operation and duration of antibiotic treatment post-operatively.

Results were presented locally to the surgical team, highlighting trust-specific guidance on prescribing in intra-abdominal infection, and input from the microbiology team.

A second 4-month cycle was completed in early 2024.

Results

Cycle 1: Data were extracted from 30 post-laparotomy patients. The most common indication for laparotomy was bowel obstruction (n=25), with confirmed perforation (n=8). The average duration of antibiotic treatment post-operatively was 11.2 days (± 7.7).

Cycle 2: Data were reviewed from 49 post-laparotomy patients. 34 patients had bowel obstruction with 8 confirmed perforations intra-operatively. The average duration of post-operative antibiotic treatment was 8.6 days (± 5.8).

Conclusions

Duration of antibiotic therapy is significantly beyond what is recommended by microbiologists and local guidelines following source-control surgery. Possible contributing factors include surgical apprehension to stepdown or stop antibiotics in the peri-operative period, and system barriers caused by electronic prescribing.
eP51 Introducing the Use of Local Anaesthetic Spray for the Insertion of Nasogastric Tubes in Emergency General Surgery
Authors: Sellers Alexandra , Lenzi Elisa , Gull Sadaf
Published: January 2025

Aims

Nasogastric tube (NGT) insertion is a common procedure used within Emergency General Surgery for patients who present with small bowel obstruction. As per current clinical guidelines, this is typically carried out without any analgesic agents, which has anecdotally resulted in reports of pain, nausea and distress from patients.

A service improvement project was undertaken to determine if using local anaesthetic (Xylocaine) spray can also improve the patient experience of having a NGT inserted with the aim of introducing a Patient Group Directive (PGD) for its use.

Methods

46 patients were given a questionnaire prospectively asking them to rate their experience of pain, nausea/vomiting and distress/anxiety following successful insertion of NGTs. Half of the group had Xylocaine spray administered prior to insertion. They were asked to rate their experiences of pain, nausea and distress on a Likert scale of 1-5 (5 being severe), as well as provide any other feedback.

Results

When prior experience was compared to the experience where Xyloxaine spray was used, fewer patients reported pain, nausea and distress at the severe end of the scale. Qualitative feedback also suggested that using Xylocaine spray improved the experience for many patients through alleviating pain to the nose and throat.

Conclusion

Local anaesthetic spray can improve the experience of pain, nausea and anxiety when undergoing NGT insertion, and numerous studies support its use. A PGD and Clinical Guideline for its use is now underway with the aim to improve patient experience and increase compliance with this intervention.
eP52 Enhancing Acute Pancreatitis Management through a Multidisciplinary Upper Gastrointestinal Team Approach: A Closed Loop Audit
Authors: Papaioannou Christos , Soni Rhea , Sheth Camy , Patwardhan Maneesha , Brewer James , Kamocka Anna
Published: January 2025

Aims

Pancreatitis is a severe, acute inflammatory condition of the pancreas, potentially leading to life-threatening complications. This closed-loop audit assessed the impact of a newly established multidisciplinary Upper GI (UGI) team on the management of acute pancreatitis patients at Chelsea and Westminster Trust.

Methods

This closed-loop audit analysed 131 patients admitted with acute pancreatitis over two 6-month periods in 2023 and 2024. Data were prospectively collected on diagnostic timing, Glasgow score calculations, imaging, and referral practices, comparing these metrics to the first audit cycle. The first cycle occurred concurrently with the introduction of the in-hospital UGI team. Interventions following the initial audit included establishing weekly benign UGI multidisciplinary team (MDT) meetings with gastroenterology and radiology specialists, streamlining the ERCP pathway, creating a "hot" cholecystectomy pathway, and implementing targeted education within the surgical department.

Results

The second audit cycle demonstrated substantial improvements. Glasgow score calculation within 48 hours increased to 50%. Escalation of severe pancreatitis cases to higher care rose from 0% to 60%. Imaging within 24 hours achieved 100% compliance. The median time from admission to ERCP decreased to 5 days. Cholecystectomy rates within 2 weeks improved from 75% to 100%, and the transfer of non-gallstone pancreatitis cases to gastroenterology increased from 33% to 50%.

Conclusion

The audit highlighted significant advancements in acute pancreatitis management, including earlier diagnosis, timely surgical interventions, and enhanced multidisciplinary care, underscoring the positive impact of the implemented measures.
eP54 Intussusception in Adults Audit
Authors: Dean Lydia , Frank Amy , Laurie Alex , Isgin Jordan , Dovell Jack , Gee Andrew
Published: January 2025

Aims

Intussusception in adults is a rare but important presentation on the emergency general surgery ‘take’. In this condition, one part of the intestine slides inside an adjacent part, which can lead to bowel obstruction and ischaemia. Unlike in children, in adults there is normally an underlying causative pathology, most commonly malignancy. Thus, bowel resection is frequently curative. This audit aimed to look at investigations, causes, and management of intussusception in adults in one district general hospital.

Methods

Data was collected for adult patients admitted under the general surgical team with imaging showing intussusception between August 2021 and 2024.

Results

71 patients were admitted during this period with intussusception on imaging. 76% of patients were diagnosed via CT scan, 16% by MRI, 4% by ultrasound, and 4% by ‘other’ types. 76% had related symptoms (such as abdominal pain and vomiting), whereas 24% were ‘incidental’ findings on imaging.

For the asymptomatic group, 41% (7 of 17) had significant pathology (5 patients had colorectal cancer, and 2 had a small bowel lipoma). All 7 patients with significant pathology had surgical resection.

For the symptomatic group, 52% (28 of 54) had significant pathology (68% had bowel cancer). 71% of patients with significant pathology were managed surgically, and 29% conservatively.

Conclusion

A large proportion of adults with intussusception on imaging will have underlying pathology that requires surgical management, and thus it is important for the emergency general surgery team to be aware of appropriately investigating patients with potential intussusception (usually with a CT scan).
eP60 Comparative Efficacy and Safety of Laparoscopic vs. Robotic Pancreatic Necrosectomy: A Systematic Review and Meta-Analysis
Authors: Karagiannidis Georgios , Banham Evie
Published: January 2025

Aims

Pancreatic necrosectomy is a critical intervention in severe acute pancreatitis, with minimally invasive techniques like laparoscopy and robotics becoming increasingly prevalent. This systematic review and meta-analysis compare the efficacy, safety, and outcomes of laparoscopic versus robotic pancreatic necrosectomy.

Methods

A comprehensive search was conducted across PubMed, Embase, and Cochrane Library databases for studies comparing laparoscopic and robotic pancreatic necrosectomy. Eligible studies were assessed for methodological quality, and data were extracted for meta-analysis.

Results

Twelve studies involving 897 patients (laparoscopic: n = 486; robotic: n = 411) were included. The meta-analysis showed similar efficacy between the two approaches in terms of necrosectomy completion rate (OR 0.78; 95% CI 0.52–1.16), operative time (MD -4.12; 95% CI -13.64–5.41), and postoperative hospital stay (MD -0.26; 95% CI -1.29–0.76). However, robotic necrosectomy was associated with significantly lower conversion rates to open surgery (OR 0.45; 95% CI 0.28–0.72) and reduced intraoperative blood loss (MD -82.14; 95% CI -122.55–-41.72). Safety outcomes, including postoperative complications and mortality rates, were comparable between the techniques.

Conclusions

Both laparoscopic and robotic pancreatic necrosectomy are effective and safe approaches for managing severe acute pancreatitis. Robotic surgery offers advantages in terms of lower conversion rates and reduced intraoperative blood loss. However, further high-quality studies are necessary to validate these findings and assess long-term outcomes.
eP64 Analysing Discharge Failure Following Subcutaneous Abscess Incision and Drainage - A quality improvement project from a High-Volume Centre in the United Kingdom
Authors: Hassan Tamer Hassan , Gull Sadaf , Abdulsatar Farah , Sellers Alexandra
Published: January 2025

Background

Incision and drainage (I&D) of Subcutaneous abscesses1 is a common procedure, and proper post-procedure care is crucial to prevent complications. Effective patient education and clear dressing instructions are vital for optimal recovery and reduce failure of discharge.

Methods

This quality improvement project aimed to reduce the failure of discharge in patients following incision and drainage (I&D) of Subcutaneous abscesses1 by enhancing the clarity and consistency of post-operative instructions. Data were collected from patient records, operative notes, and discharge notes from two separate periods. In the first period, records of 48 patients who underwent I&D were reviewed. In the second period, following the implementation of recommended changes, records of 37 patients were reviewed. The data collection focused on the presence of clear post-operative instructions and the number of patients who returned.

Results

Comparison of Findings, Clear post-operative instructions increased from 12.5% in the first period to 67% in the second period and discharge notes increased from 33.3% to 67% in addition to decreased Patient return from 14.5 % to 5.4%.

Conclusion

The significant improvements in the clarity of post-operative instructions in both operative and discharge notes have had a positive impact on patient outcomes. The reduction in patient return rates suggests that patients are better informed and better able to manage their recovery, leading to fewer complications and better overall health outcomes.

1. Perianal, pilonidal, axillary, back, abdominal wall.