bluuebunny/crossref_metadata_2025 huggingface dataset:
Nichtabrechnung von Leistungen gegenüber der Kassenärztlichen Vereinigung
Authors: Netzer-Nawrocki Juliane
Published: February 2025

Die Nichtabrechnung von ärztlichen Leistungen gegenüber den Kassenärztlichen Vereinigungen kann durch verschiedenste Beweggründe motiviert sein. Entsprechende Fallkonstellationen sind in nahezu allen vertragsärztlichen Tätigkeitsbereichen denkbar. Exemplarisch zu nennen ist der ermächtigte Krankenhausarzt, der ambulante Leistungen erbringt, die außerhalb seiner Ermächtigung liegen und damit gegenüber der Kassenärztlichen Vereinigung gar nicht abrechenbar sind. Möglich ist auch, dass der niedergelassene Vertragsarzt erbrachte Leistungen nicht abrechnet, weil er einer Plausibilitätsprüfung und ggf. einer Honorarkürzung entgehen möchte, da er am Tag eine zu große Leistungsmenge erbracht hat. Gleiches gilt für drohende Fälle einer Wirtschaftlichkeitsprüfung, wenn der Vertragsarzt im Vergleich zu seinen Fachgruppenkollegen bestimmte Leistungen auffällig häufig abrechnet. Diesen Fällen ist gemein, dass sie im streng regulierten vertragsärztlichen Abrechnungssystem nicht vorgesehen sind und sie entsprechende Sanktionen nach sich ziehen können. Der folgende Beitrag soll einen Überblick über solche Problemfälle geben.
The Benefit of Combining Kinematic Alignment and a Medial Pivot Implant in Total Knee Arthroplasty, The KA-MP Knee: Why and How
Authors: Steensen Robert N
Published: February 2025

Abstract
Kinematic alignment (KA) has emerged as an alternative alignment technique for total knee arthroplasty with the goal of duplicating the pre-arthritic joint surface. Medial pivot (MP) total knee implants duplicate the medial stability of the natural knee and recreate the medial rotational axis of the knee. Each has had favorable results. Combining the two, the KA-MP knee, creates a synergy and achieves better results than KA or MP alone.
Management of Early and Late Malperfusion Syndrome in Acute Type B Aortic Dissection with Retrograde Extension Using Hybrid Zone 2 Arch Repair and Thoracic Endovascular Aortic Repair: A Case Report
Authors: Votano Daniela , Beaufort Hector W.L. de , Mortel Rob H.W. van de , Sonker Uday , Heijmen Robin H. , Smeenk Hans G.
Published: February 2025

The distal extent of aortic repair in acute aortic dissection and the management of malperfusion in terms of timing and strategy are still debated topics. We present a case of acute type B dissection with retrograde extension to the ascending aorta, with the most proximal intimal tear in the descending thoracic aorta, associated with both early lower extremity and delayed mesenteric malperfusion syndrome, treated effectively by femoral artery open fenestration and hybrid zone 2 arch repair.
Two-dimensional Brownian motion with dependent components: Turning
angle analysis
Authors: Balcerek Michał , Pacheco-Pozo Adrian , Wyłomańska Agnieszka , Burnecki Krzysztof , Krapf Diego
Published: February 2025

Brownian motion in one or more dimensions is extensively used as a stochastic process to model natural and engineering signals, as well as financial data. Most works dealing with multidimensional Brownian motion consider the different dimensions as independent components. In this article, we investigate a model of correlated Brownian motion in R2, where the individual components are not necessarily independent. We explore various statistical properties of the process under consideration, going beyond the conventional analysis of the second moment. Our particular focus lies on investigating the distribution of turning angles. This distribution reveals particularly interesting characteristics for processes with dependent components that are relevant to applications in diverse physical systems. Theoretical considerations are supported by numerical simulations and analysis of two real-world datasets: the financial data of the Dow Jones Industrial Average and the Standard and Poor’s 500, and trajectories of polystyrene beads in water. Finally, we show that the model can be readily extended to trajectories with correlations that change over time.
Quantifying tipping behavior: Geometric early warnings and quasipotentials for a box model of AMOC
Authors: Chapman Ruth R. , Ashwin Peter , Wood Richard A.
Published: February 2025

A non-autonomous system can undergo a rapid change of state in response to a small or slow change in forcing, due to the presence of nonlinear processes that give rise to critical transitions or tipping points. Such transitions are thought possible in various subsystems (tipping elements) of the Earth’s climate system. The Atlantic Meridional Overturning Circulation (AMOC) is considered a particular tipping element where models of varying complexity have shown the potential for bi-stability and tipping. We consider both transient and stochastic forcing of a simple but data-adapted model of the AMOC. We propose and test a geometric early warning signal to predict whether tipping will occur for large transient forcing, based on the dynamics near an edge state. For stochastic forcing, we quantify mean times between noise-induced tipping in the presence of stochastic forcing using an Ordered Line Integral Method of Cameron (2017) to estimate the quasipotential. We calculate minimum action paths between stable states for various scenarios. Finally, we discuss the problem of finding early warnings in the presence of both transient and stochastic forcing.
Magnetic hardness of hexagonal and orthorhombic Fe3C, Co3C, (Fe–Co)3C, and their alloys with boron, nitrogen, and transition metals: A first-principles study
Authors: Snarski-Adamski Justyn , Werwiński Mirosław , Rychły-Gruszecka Justyna
Published: February 2025

Restrictions on the availability of rare earth metals create a strong demand for new rare-earth-free hard magnetic materials. In this study, we considered a large set of materials that are closely related to orthorhombic Fe3C (cementite) with the aim of characterizing trends in their intrinsic magnetic properties, highlighting the relation between magnetic properties and the chemical composition, and identifying alloys that are optimal for applications. A comprehensive analysis was conducted on the full concentration ranges of hexagonal (ϵ) and orthorhombic (θ) phases of (Fe–Co)3C, (Fe–Co)3(B–C), (Fe–Co)3(C–N), and their alloys with 3d, 4d, and 5d transition metals. The calculations were performed using the density functional theory implemented in the full-potential local-orbital code. Calculated properties included formation energies, Curie temperatures, magnetic moments, magnetocrystalline anisotropy energies (MAEs), and magnetic hardnesses. The considered compositions exhibit a range of magnetic properties, including soft, semi-hard, and hard magnetic. The materials most promising for hard-magnetic applications are selected Co-rich orthorhombic and hexagonal (Fe, Co)3C alloys. The calculation results do not indicate that substituting with transition metals increases the potential of the alloys for permanent magnet applications. A significant drawback of alloying orthorhombic θ–Fe3C (cementite) with transition metals is the notable decline in the Curie temperature. Among the positive outcomes, we found that a considerable proportion of the orthorhombic Co3(B–C–N) alloys are magnetically hard, of which boron substitution raises the Curie temperature and improves stability. By mapping the dependence of MAE on the concentration of elements covering both the 3d (from Fe to Co) and 2p (from B, through C, to N) positions, we have demonstrated for the first time the near isoelectronic nature of MAE. The latter observation may be particularly useful in designing compositions of new magnetically hard materials.
Anisotropic behavior of plasmons in kagome metal YCr6Ge6
Authors: Agboola Babafemi S. , Reyes-Gonzalez Joaquin E. , Sharma Sudarshan , Gautreau Jonah , Luke Graeme M. , Lagos Maureen J.
Published: February 2025

We report on the growth of YCr6Ge6, which crystalizes in the hexagonal crystal structure with Cr atoms adopting a kagome lattice. The plasmon dispersion of YCr6Ge6 was investigated with momentum resolved electron energy loss spectroscopy revealing an anisotropic behavior along the [101̄0] (in-plane) and [0001] (out-of-plane) propagating directions. Group velocities are one order of magnitude smaller than those in traditional free-electron gas metals. Damping processes occur within the particle–hole continuum band. This study provides insights into the role of complex band structure in the plasmon behavior of kagome metals and alternatives in the search for new plasmonic materials.
Computational fluid dynamics challenge on indoor dispersion of pathogen-laden aerosols
Authors: Pallares Jordi , Fabregat Alexandre , Lavrinenko Akim , Marques Nelson , Santos Bruno , Mosca Gabriele , Vega Pedro Obando , Ravnik Jure , Vovk Nejc , Fraga Bruño , Monka Aleksandra , Martínez Manuel , Mestre-Curto Naomi , Souza Francisco Jose de , Fontes Douglas , Jüngling Natalie , Niessner Jennifer , Castilla Robert , García-Vílchez Mercè , Fletcher David F. , Inthavong Kiao , Hriberšek Matjaž , Steinmann Paul , Wedel Jana , Duchaine Florent , Sankurantripati Shriram , Amari Leo , Janiga Gábor , Marchioli Cristian , Cito Salvatore
Published: February 2025

This paper presents and discusses the results of the “2024 International Computational Fluid Dynamics Challenge on the long-range indoor dispersion of pathogen-laden aerosols” aimed at assessing the ability of different computational codes and turbulence models to reproduce the dispersion of particles produced by a turbulent natural convection flow enclosed in a room sized cubical cavity. A total of 12 research groups from ten different countries have conducted 15 simulations of the same flow configuration by solving the Reynolds averaged Navier–Stokes (RANS) equations, the unsteady Reynolds averaged Navier–Stokes (URANS) equations or using scale adaptive simulations (SAS), large-eddy simulations (LES), or hybrid (URANS-LES) techniques. Results for the velocity field and the particle dispersion provided by the different simulations are compared extensively, including the reference results provided by a direct numerical simulation (DNS). In general, LES and hybrid methods reproduce the time-averaged flow field correctly, the spatial distribution of the turbulence kinetic energy, and the particle dispersion. The performance of SAS is similar to that of LES and hybrid methods while the predictions of the RANS and URANS simulations exhibit larger deviations with respect to DNS. In general, the particle dispersion is better reproduced by simulations that capture correctly the spatial distribution of the turbulence kinetic energy.
Transient Newtonian Poiseuille flow in a square channel with dynamic wall slip
Authors: EL Farragui Meryieme , Souhar Otmane , Georgiou Georgios C.
Published: February 2025

We analytically solve the transient Newtonian Poiseuille flow in a square channel in the presence of wall slip, which obeys a dynamic equation that extends the static Navier slip law by means of a slip relaxation parameter. The Fourier method is employed considering the appropriate Sturm–Liouville problem in order to account for the presence of time derivative (and thus of the eigenvalues of the problem) in the boundary conditions deriving the proper orthogonality condition for this two-dimensional flow. All desired eigenvalues are determined numerically. The analytical solution yields available analytical solutions for certain special cases and is validated fully explicit finite difference solutions. Comparisons are also made with available results in the literature for one-dimensional Newtonian flows with dynamic wall slip. The effects of the slip relaxation parameter on the evolution of the velocity field and the volumetric flow rate are discussed, and the deceleration of the flow cessation with the slip relaxation parameter is analyzed. It is demonstrated that both slip and the slip relaxation parameter delay flow cessation and that the effect of the latter is more pronounced when wall slip is moderate.
Direct numerical simulation of the supersonic turbulent boundary layer of supercritical carbon dioxide
Authors: Wang Jinhong , Yang Bijie , Martinez-Botas Ricardo , Cao Teng
Published: February 2025

This paper presents a study of the turbulent boundary layer of supercritical carbon dioxide (sCO2) over an adiabatic flat plate using direct numerical simulation (DNS). As a non-ideal fluid, sCO2's non-ideal behaviors in the turbulent boundary layer are studied by comparing it with a perfect gas air case. Both the mean flow and the turbulent behaviors are investigated. In addition, the skin friction coefficient (Cf) and the dissipation coefficient (Cd) are analyzed due to their significance in engineering applications. The mean flow results reveal that sCO2 has lower temperature variation within the boundary layer than air due to its large Eckert number. By revising Walz's equation, it was found that Walz's equation in its classic form (using temperature ratios) fails to predict the temperature profile for sCO2, but its enthalpy form can accurately predict the enthalpy distribution. The viscosity of sCO2 displays liquid-like behavior inside the boundary layer. From the turbulent fluctuation behavior view, sCO2 boundary layer exhibits lower temperature fluctuations than air. Higher velocity fluctuation intensities are introduced due to local Reynolds number variation. Morkovin's hypothesis is still valid in sCO2 flow and no major differences are observed in the turbulent kinetic energy budget and velocity fluctuation intensities between sCO2 and air. Additionally, the van Driest II transformation for Cf relations is inapplicable for non-ideal compressible fluids, and the property ratio method is suggested as a promising alternative. Although the dissipation coefficient Cd is at a similar level for both air and sCO2 in this study, its components behave differently within the boundary layer due to the property variations.
A deep convolutional neural network for diffuse correlation tomography
Authors: Liu Jiaxin , Wang Jihui , Shang Yu
Published: February 2025

Near-infrared diffuse correlation tomography (DCT) is an emerging technology for tomographic imaging of blood flow index (BFI) in biological tissues through quantifying the light electric field temporal autocorrelation function. With the conventional approaches, proper reconstruction of BFI images is a challenging task from the limited DCT signals due to the severe imbalance between the optical measurements and the voxels to be reconstructed. In this study, we proposed a complete deep learning solution for DCT, including a dataset containing massive prior information for network training, a long short-term memory neural network for DCT signal denoising, as well as a deep convolutional neural network for mapping the DCT signals into the tomographic BFI images. The proposed deep learning solution was comprehensively validated through both computer simulations and phantom experiments, demonstrating its strong superiority over the conventional approach for precise and robustness reconstructions of the target BFI anomalies, with much better performance in reducing errors (i.e., the mean absolute error was reduced by 26.1 times) and preserving fine structure (i.e., the structure similarity index measure was increased by 12.8 times). The proper establishment of a deep learning strategy enables future exploration of the microvasculature blood flow mechanism on pathological tissues even from the limited DCT signals.
Cryo-EM heterogeneity analysis using regularized covariance estimation and kernel regression
Authors: Gilles Marc Aurèle , Singer Amit
Published: February 2025

Proteins and the complexes they form are central to nearly all cellular processes. Their flexibility, expressed through a continuum of states, provides a window into their biological functions. Cryogenic electron microscopy (cryo-EM) is an ideal tool to study these dynamic states as it captures specimens in noncrystalline conditions and enables high-resolution reconstructions. However, analyzing the heterogeneous distributions of conformations from cryo-EM data is challenging. We present RECOVAR, a method for analyzing these distributions based on principal component analysis (PCA) computed using a REgularized COVARiance estimator. RECOVAR is fast, robust, interpretable, expressive, and competitive with state-of-the-art neural network methods on heterogeneous cryo-EM datasets. The regularized covariance method efficiently computes a large number of high-resolution principal components that can encode rich heterogeneous distributions of conformations and does so robustly thanks to an automatic regularization scheme. The reconstruction method based on adaptive kernel regression resolves conformational states to a higher resolution than all other tested methods on extensive independent benchmarks while remaining highly interpretable. Additionally, we exploit favorable properties of the PCA embedding to estimate the conformational density accurately. This density allows for better interpretability of the latent space by identifying stable states and low free-energy motions. Finally, we present a scheme to navigate the high-dimensional latent space by automatically identifying these low free-energy trajectories. We make the code freely available at
https://github.com/ma-gilles/recovar
.
Directed evolution of a sequence-specific covalent protein tag for RNA labeling
Authors: Huang Rongbing , Ting Alice Y.
Published: February 2025

Efficient methods for conjugating proteins to RNA are needed for RNA delivery, imaging, editing, interactome mapping, and barcoding applications. Noncovalent coupling strategies using viral RNA binding proteins such as MS2/MCP have been widely applied but are limited by tag size, sensitivity, and dissociation over time. We took inspiration from a sequence-specific, covalent protein–DNA conjugation method based on the Rep nickase of a porcine circovirus called “HUH tag”. Though wild-type HUH protein has no detectable activity toward an RNA probe, we engineered an RNA-reactive variant, called “rHUH”, through 7 generations of yeast display–based directed evolution. Our 13.4 kD rHUH has 12 mutations relative to HUH and forms a covalent tyrosine-phosphate ester linkage with a 10-nucleotide RNA recognition sequence (“rRS”) within minutes. We engineered the sensitivity down to 1 nM of target RNA, shifted the metal ion requirement from Mn
2+
toward Mg
2+
, and demonstrated efficient labeling in mammalian cell lysate. This work paves the way toward a potentially powerful methodology for sequence-specific covalent protein–RNA conjugation in biological systems.
A novel multiple-prototype and domain adversarial network for few-shot cross-domain fault diagnosis
Authors: Shi Peiming , Dai Siyu , Xu Xuefang , Han Dongying
Published: February 2025

Since deep learning has been introduced into the field of intelligent fault diagnosis it has made significant accomplishments with large amounts of data. However, in practical industrial settings there is a general lack of labeled data and operating conditions are not stable, therefore existing trained models ignore these problems and diagnostic accuracy and generalization are severely degraded. Therefore, this study proposes a multiple-prototype, domain adversarial network for fault diagnosis of rotating machinery, especially bearings, to address the issues of domain distribution shift and a shortage of labeled samples from the target domain. Firstly, the proposed method adopts a residual network with 12 layers (ResNet12) as the encoder to extract distinct features from the target domain and source domain data. Then, a domain-invariant representation module, using the domain adversarial method, is introduced to bridge the discrepancy between a source and target pair domain. Furthermore, a class typicality weight module is designed to calculate weights by constructing multiple prototypes of the source and target domains to improve the generalization of the model. Extensive experiments are executed on two datasets with variable working conditions to test and verify the feasibility and superiority of the proposed method.
Application of graph networks to a wide-field water-Cherenkov-based Gamma-ray Observatory
Authors: Glombitza J. , Schneider M. , Leitl F. , Funk S. , van Eldik C.
Published: February 2025

With their wide field of view and high duty cycle, water-Cherenkov-based observatories are integral to studying the very high-energy gamma-ray sky. For gamma-ray observations, precise event reconstruction and highly effective background rejection are crucial and have been continuously improving in recent years. In this work, we investigate the application of graph neural networks (GNNs) to background rejection and energy reconstruction and benchmark their performance against state-of-the-art methods.
In our simulation study, we find that GNNs outperform hand-designed classification algorithms and observables in background rejection and find an improved energy resolution compared to template-based methods.
A multi-Hough-based displaced vertex track trigger for the Belle II experiment
Authors: Unger Kai Lukas , Becker Jürgen , Forsthofer Timo , Hiesl Simon , Kiesling Christian , Neu Marc , Schmidt Elia , Meggendorfer Felix , Mi Tiancheng , Ou Zuwen
Published: February 2025

The Belle II experiment at the asymmetric-energy electron positron collider SuperKEKB aims to explore physics beyond the standard model (BSM). One of the widely discussed signatures for BSM are new, long-lived neutral particles, which decay into charged mesons or lepton pairs originating from a vertex usually far from the interaction point (IP) of the colliding beams. The current level-1 (L1) track trigger system is optimized for particles created at the IP and will thus reject, with high probability, such interesting events. This makes it necessary to develop a special L1 track trigger for events with a vertex displaced from IP, the Displaced Vertex Trigger (DVT). The pipelined and deadtime-free L1 trigger system of Belle II utilizes a set of FPGA boards to make rapid decisions within 5 microseconds. The new DVT will be operating in parallel with the existing track trigger systems. The DVT identifies events, where two tracks with opposite charge originate from a common vertex away from the IP. The track finding is done by a set of Hough transformations, each one assuming a certain track origin from a grid spanning the tracking volume. The correct vertex is then determined via a shape analysis of the Hough clusters, using neural networks. To manage the large number of track origin hypotheses, a pre-selection of candidates based on the properties of the Hough map is employed, which significantly reduces the required FPGA resources.
Research on online RF tuning of DTL accelerator for CSNS-II energy upgrade
Authors: Li Ahong , Qu Peihua , Liu Huachang , Meng Lin , Wang Sheng , Wu Xiaolei , Li Bo , Fan Mengxu , Zhou Wenzhong , Zhang Cong , Chen Qiang , Yang Yao , Wang Yuqi
Published: February 2025

With the energy upgrade of the China Spallation Neutron
Source (CSNS-II) and the increasing demand for isotope production,
the RF repetition frequency of the Drift Tube Linac (DTL)
accelerator must be elevated from 25 Hz to 50 Hz. However, the
frequency shifts induced by RF heating exceed the current tuning
range. Traditional tuning methods cannot be applied during DTL
operation, so online tuning technology is explored in this
study. Multi-physics simulations were used to analyze the
electromagnetic and temperature distribution, frequency shifts, and
compensation strategies. It was found that adding tuning blocks on
the side of the cavity is the optimal solution. Two types of tuning
blocks were developed and installed during the summer maintenance,
achieving a beam transmission rate of over 98%. Experimental
results showed that the new tuning blocks effectively compensated
for the frequency deviation without affecting the cavity's stability
or field distribution. This solution improves the high-frequency
performance of the DTL accelerator and meets the upgraded
requirements. It is practical approach that offers valuable insights
for the online tuning of DTL accelerators, as well as other
high-frequency cavities.
The optimal structure of the MRPC detector for 0.511 MeV gamma based on Monte Carlo simulation
Authors: Liu J. , Chen Z. , Wang Y. , Guo B. , Han D. , Li Y.
Published: February 2025

The detailed simulation of the Multi-gap Resistive Plate
Chambers (MRPCs) provides the performance characteristics of MRPCs
with different numbers of gas gaps and gap thicknesses. This helps
in optimizing the structure of MRPCs under specific conditions by
balancing time resolution, detection efficiency, and other
performance metrics. To obtain the optimal structure of MRPCs for
0.511 MeV gammas, a complete simulation framework for gamma
detection by the MRPCs based on Geant4 and Magboltz software is
described in this paper. The simulation shows how gammas interact
with MRPCs and the process of gas ionization, avalanche
multiplication, and signal formation. The simulation results are in
good agreement with the experimental results. By analyzing the time
resolution and detection efficiency, the optimal structure of MRPCs
for 0.511 MeV gammas is proposed.
Unified analysis of the semidiscrete discontinuous Galerkin methods for 2-D hyperbolic equations on Cartesian meshes using ℙ^{𝕜} elements: optimal error estimates and superconvergence
Authors: Cao Waixiang , Shu Chi-Wang , Zhang Zhimin
Published: February 2025

This paper is concerned with optimal error estimates and superconvergence properties of the discontinuous Galerkin (DG) method for two-dimensional hyperbolic conservation laws on uniform Cartesian meshes when piecewise polynomials of degree not more than

k
k

(i.e.,

P

k

{\mathbb P}^k

elements) are used. Superconvergence result of the DG approximation errors for the cell average and for the downwind edge average with an order of

O

(

h

k
+
2

)

{\mathcal O}(h^{k+2})

is derived, under the condition that the wind direction does not change sign on the whole domain. As a byproduct, an optimal convergence rate of order

O

(

h

k
+
1

)

{\mathcal O}(h^{k+1})

in the standard

L
2

L^2

norm is obtained for both linear and nonlinear hyperbolic equations. Numerical experiments are presented to verify our theoretical findings.
Revealing the antimicrobial potential of traditional Chinese medicine through text mining and molecular computation
Authors: Chung Meng-Chi , Su Li-Jen , Chen Chien-Lin , Wu Li-Ching
Published: February 2025

Traditional Chinese Medicine (TCM), with its extensive knowledge base documented in ancient texts, offers a unique resource for contemporary drug discovery, particularly in combatting microbial infections. The success of antimalarial drugs like artemisinin and artesunate, derived from the TCM herb Artemisia annua L., exemplifies the potential of TCM-derived small molecules. This rich repository of natural products and intricate molecular structures could reveal novel compounds with unexplored mechanisms of action. Our study employs a multifaceted approach that combines text mining, detailed textual analysis, and modern antibacterial molecular prediction methodologies to unlock the potential of ancient TCM remedies. We use external knowledge maps, which include databases of known bioactive compounds and their targets, to identify promising TCM candidates. This approach leverages both historical texts and contemporary scientific data to explore the therapeutic potential of TCM. We discovered that herb patterns DiYu→ZeXie and Kushen→ShengJiang potentially combat both Grams-positive and Grams-negative bacteria. We utilized the AntiBac-Pred online tool to identify and analyze the chemical components of herbs, integrating data from ancient texts and TCMDB@Taiwan external knowledge graph. The DiYu→ZeXie groups showed antimicrobial potential against resistant Staphylococcus simulans, while the Kushen→ShengJiang groups exhibited dual antimicrobial effects against Bacillus subtilis. Exploring TCM’s extensive repository offers numerous opportunities for discovering therapeutically active compounds. Our synergistic approach, which combines ancient wisdom with modern science, holds significant promise for enhancing our ability to combat infectious diseases. This method could pave the way for a new era of personalized medicine, addressing the urgent need for innovative treatments against multidrug-resistant bacteria and viruses.
IBC Oxford University Oral Abstract 2 - Small bowel obstruction due to intraluminal clot (haemobezoar) following laparoscopic gastric bypass—different clinical approaches to a rare complication of bariatric surgery—a case series from a tertiary hospital
Authors: Teixeira J P Araújo , Pinho A Costa , Nogueiro J , Almeida N M , Cruz D , Lemos J , Peleteiro B , Resende F , Preto J , Freitas P , Sousa H Santos , Carneiro S , da Costa E Lima
Published: February 2025

Introduction

The incidence of small bowel obstruction (SBO) after Roux-en-Y gastric bypass (RYGB) ranges from 0.6% to 3.5%, with common causes being surgical adhesions, internal hernias, and anastomotic stenosis. Intraluminal clots causing obstruction are rare. A PubMed search for ‘small bowel obstruction’ AND (‘haemobezoar’ OR ‘intraluminal clot’ OR ‘blood clot’) identified 27 cases reported between 2005 and 2024. This study presents three cases of SBO due to intraluminal clots at the jejuno-jejunostomy in patients who underwent laparoscopic RYGB.

Methods

A retrospective analysis was conducted on three patients who experienced SBO caused by an intraluminal clot after laparoscopic RYGB performed by the CRI-O group. Of 2117 laparoscopic RYGB performed between 2019–2023, 47 (2.22%) had post-operative bleeding and 5 (0.24%) had post-operative SBO. Baseline demographic, preoperative, and intraoperative factors among patients with and without early postoperative bleeding were analysed. Data on preoperative conditions, symptoms, diagnostic methods, and treatment outcomes were collected of each case. The primary outcome was to detail the clinical presentation and management of SBO caused by intraluminal clots.

Results

Three female patients, with a mean BMI of 41.9 kg/m2 and a mean age of 43 years, presented with SBO due to intraluminal clots located at the jejuno-jejunostomy within the first two postoperative days. Symptoms included haematemesis, haematochezia, nausea, vomiting, and abdominal pain, with tachycardia being the most frequent clinical sign. All patients required blood transfusions and were diagnosed using CT scans with intravenous contrast. Surgical intervention varied: two patients underwent emergency surgery due to haemorrhagic shock, involving decompression of the gastric remnant and clot removal, although with different approaches. One patient, hemodynamically stable, was managed conservatively.

Conclusion

SBO caused by intraluminal clots post-RYGB is a rare, but serious complication. Early symptoms include signs of gastrointestinal bleeding and intestinal obstruction, with tachycardia being a frequent indicator. Haemodynamic instability necessitates urgent surgical intervention to prevent severe outcomes like ischemia and septic shock. Conservative management can be effective in hemodynamically stable patients. This case series highlights the importance of prompt diagnosis and individualized treatment strategies for SBO caused by intraluminal clots post-RYGB.
IBC Oxford University Oral Abstract 7 - Outcomes of Braun procedure for reflux after OAGB- audit from a single centre
Authors: Kaur M , Haider I , Baruah V , Javed S , Stewart D , Darrien J , Almerie Q , Kerrigan D
Published: February 2025

Introduction

One anastomosis gastric bypass is an established bariatric procedure that gives good weight loss and resolution of obesity related morbidity. However, some patients suffer with bile reflux, presenting with debilitating symptoms like vomiting, nausea and retro-sternal burning. These symptoms can be difficult to control medically, and some patients require surgical intervention. Conversion to Roux-en-Y bypass is the most common procedure but it is major revisional surgery. Braun procedure, consisting of jejuno-jejunal anastomosis 30 cm distal to GJ anastomosis to bypass bile away from stomach is a less invasive option.

Methods

In this retrospective study of a prospective database, we analysed the outcomes of all the patients who underwent Braun procedure from October 2016–January 2024 for resolution of symptoms of bile reflux and to compare them with those of RYGB conversion. Patients who present with bile reflux are managed in the MDT setting and offered medical management. Diagnosis is confirmed with OGD and Barium study. Non-respond and those with severe reflux are offered surgical options of Braun Procedure and RYGB. Choice of procedure is based on MDT discussion considering the severity of reflux, quality of life, percentage excess weight loss and patient’s choice.Steps of Braun surgery- Video link.

Results

Total number of OAGB procedures done were 1024, 35 patients (3.4%) presented with bile reflux needing surgical management. 31/35 (88.6%) underwent Braun procedure. 4/35 (11.4%) underwent conversion to RYGB (3 for poor weight loss/weight regain and 1 patient choice). 27/31 Braun’s patients (88%) had immediate resolution of reflux symptoms, 23 (74%) maintained at 2 years follow up. None of the 4 had conversion to RYGB with 3 well controlled on PPI and one refused further surgery. 4/31 (13%) Braun’s patients did not improve at all. These were converted to RYGB. In total 8 patients had RYGB conversion (4 primary and 4 after failed Braun’s). All these patients had resolution of symptoms at 1 year follow up. There was no significant morbidity in either group. OAGB to RYGB group had 2 days hospital stay versus Braun group treated as day case.

Conclusions

Conversion to RYGB is the gold standard procedure for managing bile reflux Braun’s procedure is a safe and effective day case procedure with acceptable success rate and should be considered as an alternative.
IBC Oxford University Oral Abstract 21 - Video abstract: laparoscopic giant hydatid cyst and sleeve gastrectomy surgery
Authors: Kasapoğlu İ
Published: February 2025

Introduction

Sleeve Gastrectomy despite being the most performed and an effective bariatric surgery is not always straight forward and coexisting pathologies like hydatid cyst liver disease make it more difficult. We present a video of laparoscopic giant hydatid cyst excision with Sleeve Gastrectomy simultaneously. A video presentation will be made, and the technique of surgery will be analysed.

Methods

The case is a 46-year-old man with BMI of 60 kg/m2 with severe back pain due to a prolapse disc which had not been operated on because of his obesity. He consulted us for weight reduction surgery and was found to have a large hydatid cyst on preoperative ultrasound confirmed by CT abdomen which showed a 20 cm by 20 cm cyst occupying most of the left lobe and some of the central part of the liver. Laparoscopic sleeve surgery was done using 5 trocars. The cyst was punctured and emptied with care to avoiding spillage of the cyst content then part of the cyst excised. After that sleeve gastrectomy done and at the end of the surgery 3 drains were placed; one along the sleeve staple line, one drain adjacent to the cyst and a T tube drain inside the cyst cavity.

Results

Postoperatively the patient was mobilised 3 hours after the surgery and discharged on day 3 post operatively. The sleeve drain was removed on postoperative day 2, the para-cystic drain on day 10 and the T tube on day 20. The patient was reviewed ion postoperative day 10, day 30 and day 90. At 6 months the patient had lost 60 kg and had no complications related to the cyst drainage and excision.

Conclusions

Laparoscopic hydatid cyst excision and sleeve gastrectomy can be done effectively if the expertise is available. Further cases and studies are required to support our experience.
IBC Oxford University Oral Abstract 26 - The outcome of concomitant laparoscopic cholecystectomy and sleeve gastrectomy in patients with morbid obesity: a systematic review and meta-analysis
Authors: Bawahab M
Published: February 2025

Objective

Gallstones are up to five times more common in obese people than in healthy people. Several studies have demonstrated the safety of prophylactic cholecystectomy in patients without gallstones during bariatric surgeries. However, no evidence supports its safety in patients with gallstones. Therefore, this study aimed to evaluate the safety and effect of concomitant cholecystectomy (CC) for asymptomatic cholelithiasis (AC) patients during LSG on postoperative complications.

Material and Methods

A systematic review and meta-analysis were performed according to the PRISMA guidelines. Two groups of patients (CC and LSG alone) were compared regarding operative duration, hospital stay, and intraoperative and postoperative surgical complications. Analysis was performed using RevMan software.

Results

Operative time was significantly longer among those who underwent CC, with a mean difference of 28.89 minutes (95% c.i.: 22.77 to 35.02 minutes). Associated complications and length of hospital stay did not differ significantly between the two groups (OR: 1.38, 95% c.i.: 0.99 to 1.91, and a mean difference of 0.12, 95% c.i.: −0.05 to 0.29 days, respectively).

Conclusion

This study provides evidence that confirms the safety of performing CC during sleeve gastrectomy in patients with asymptomatic gallstones.
IBC Oxford University Oral Abstract 33 - The role of bariatric surgery in the management of psoriasis: a systematic review and meta-analysis
Authors: Alves A L , Pinto A C , Pinheiro F , Rosa R , Resende F , Costa-Pinho A , Preto J , Carneiro S , da Costa E Lima , Sousa-Pinto B , Santos-Sousa H
Published: February 2025

Background

Psoriasis is a chronic immune-mediated skin disease that is more prevalent and severe in obese patients. To the best of our knowledge, no systematic review about the influence of bariatric surgery in the management of psoriasis has been conducted until now. Therefore, we aimed to systematically review all the current literature about the presumptive positive effects of bariatric surgery in the management of psoriasis, evaluating the impact of surgery in psoriasis improvement.

Methods

We conducted our systematic review and meta-analysis in accordance with the guidelines outlined in the Preferred Reporting Items for Systematic Reviews and Meta- Analyses (PRISMA). We searched three major databases: PubMed, Scopus, and Web of Science. We evaluated qualitatively the included studies and in our meta-analysis, we focused on evaluating the dichotomous variable of ‘Downgrade of Systemic Medication after Surgery,’ an indirect measure of psoriasis improvement, analyzing the proportion of patients experiencing this outcome.

Results

The analysis included four studies with a total of 127 participants and 69.3% of them were women. Roux-en-Y Gastric Bypass was the most common procedure (78%). Three studies evaluated psoriasis improvement post-surgery, showing improvements ranging from 39.4% to 70% based on DLQI score, ABSA score, and even on subjective evaluation by the patients. Metabolic comorbidities improvement was confirmed in two studies and older age was also associated with a higher probability of improvement. Results from the meta-analysis showed that out of 67 patients using systemic medications, 45% (Proportion = 0.45, 95% c.i. [0.33;0.57]) experienced reduced medication post-surgery.

Conclusion

Although there is promising evidence of psoriasis improvement following bariatric surgery, the limited number of studies and participants prevents broad generalization to real-world situations. This underscores the necessity for additional research, particularly randomized studies, to determine whether bariatric surgery offers superior outcomes compared to alternative weight loss interventions for managing and improving psoriasis in obese patients.
IBC Oxford University Oral Abstract 36 - Predictive factors of postoperative haemorrhagic complications after laparoscopic Roux-En-Y gastric bypass: analysis of a high-volume centre
Authors: Coutinho C , Santos-Sousa H , Nogueiro J , Machado M , Oliveira A , Lemos J , Peleteiro B , Resende F , Costa-Pinho A , Preto J , Freitas P , Carneiro S , da-Costa E Lima
Published: February 2025

Introduction

Laparoscopic Roux-En-Y gastric bypass (LRYGB) is one of the most performed procedures for morbid obesity. Morbidity and mortality associated with bariatric surgery are considered low. Nevertheless, post-operative haemorrhage is the most frequent early complication after LRYGB.

Methods

We conducted a retrospective cohort study regarding all patients submitted to LRYBG between 2019 and 2023 at our centre. Postoperative haemorrhage was defined as clinically significant evidence of bleeding in the early postoperative period (first 30 days). Demographic, preoperative and intraoperative characteristics of our population were evaluated. We aimed to assess associations and predictive factors of postoperative haemorrhage in our population.

Results

Our population comprised a total of 2117 patients submitted to LRYGB. Most were female (86.3%) and mean age was 47 years old. Mean pre-surgical body mass index (BMI) was 41.8 kg/m2. Regarding previous comorbidities, 23.1% had diabetes, 44.2% hypertension and 33.1% dyslipidaemia. Of the 2117 cases, 307 (14.5%) were revisional surgeries. Concerning postoperative complications, 47 (2.2%) patients had early postoperative haemorrhagic events. Of those, 2 (4.2%) had extraluminal haemorrhage and underwent surgical reintervention. The remaining 45 (95.8%) had intraluminal bleeding and were managed conservatively. Previous cholecystectomy was significantly more prevalent amongst these patients (21.3% versus 11.0%, P = 0.028). However, no statistically significant differences were found according to age, gender, pre-surgical BMI, left liver lobe diameter as well as for revisional surgery. Patients with bleeding complications had a longer hospital stay (2.8 days versus 3.7 days) as well as higher number of reinterventions and readmissions (8.5% versus 3.1%, P = 0.039 and 10.6% versus 3.4%, P = 0.008, respectively). Early postoperative complications include leakage, bleeding and obstruction. Even though these are considered common, postoperative morbidity remains low, particularly in high-volume centres. Adequate and on time management is of utmost important.

Conclusions

Intraluminal bleeding is usually managed conservatively, especially if hemodynamical stability is present, however extra-luminal haemorrhages are more likely to impose surgical treatment, just as shown in our series. Importantly, one must focus on the early detection, diagnosis and treatment for the purpose of patient and treatment outcome improvement. The identification of risk factors for such complications is of utmost importance, to allow for the implementation of perioperative strategies in high-risk patients.
IBC Oxford University Oral Abstract 46 - Bariatric surgery for adolescent obesity: what is the current evidence?
Authors: Foula M , AlJoaib N , AlGhamdi F , AlOtaibi G , Alratrout H , AlArfaj M , Aldabeab A , Zakaria H
Published: February 2025

Objectives

In this systematic review and meta-analysis, we aimed to assess the impact of bariatric surgical procedures on weight reduction in adolescents. Laparoscopic sleeve gastrectomy (LSG), laparoscopic adjustable gastric band (LAGB), and laparoscopic Roux-en-Y gastric bypass (LRYGB) were evaluated, along with their associated complications.

Methods

We conducted a systematic review following PRISMA and Cochrane Handbook guidelines, searching databases from inception to May 12, 2023. Inclusion criteria comprised studies in the English language investigating the effects of bariatric surgery on weight loss, reporting BMI outcomes, and involving human adolescents. The quality assessment used the Newcastle-Ottawa Scale and the National Institutes of Health tool, and the meta-analysis was conducted using Stata software.

Results

From 1,826 initial studies, 56 met our inclusion criteria, and 45 were included in the meta-analysis. LSG and LAGB showed significant body mass index (BMI) reductions up to the 60th postoperative week (LSG: −10.008, P = 0.002; LAGB: −9.684, P = 0.003). Also, LRYGB demonstrated a significant and sustained BMI reduction, notably at 24th postoperative weeks (−18.076, P < 0.001) and 36th postoperative weeks (−18.145, P < 0.001). Minimal complications were reported after LRYGB and LAGB. However, LSG was associated with a 1% incidence of hernia (Relative Risk (RR) = 0.01, P = 0.001), an 11% occurrence of cholecystectomy (RR = 1.1, P = 0.01), and a 10% leak incidence (RR = 1.01, P = 0.01).

Conclusion

This systematic review and meta-analysis highlights the efficacy of bariatric surgery in reducing BMI among adolescents. LSG, LAGB, and LRYGB all yielded significant and sustained BMI reductions. While complications were generally low, LSG exhibited specific risks, emphasizing the importance of individualized patient assessment.
IBC Oxford University Oral Abstract 47 - 12-years’ experience with the endoscopic sleeve gastroplasty: suggestion for an upgraded device
Authors: Dargent J
Published: February 2025

Introduction

The Endoscopic Sleeve Gastroplasty represents an innovative and successful solution in the bariatric field. Starting in 2011, we introduced it in our practice in Lyon.

Methods

We performed 92 EGP till 2023, both primary (N = 71) and secondary (N = 21). The learning curve has been steep concerning at least one device (Apollo Endosurgery, N = 55), while easier with Endomina (N = 16) and POSE (USGI Medical) (N = 20).

Results

All patients stayed overnight, 5 stayed 2 days or more. 19 patients were included into a re-do protocol in former bypass (aimed at narrowing a gastro-jejunal anastomosis). There were mild complications in 32 patients (35%), mostly abdominal pain with marginal pneumoperitoneum in 10, non-specific abdominal pain in 30, and nausea in 21, and SAE in one patient (pneumo-mediastinum, spontaneously resolutive). Weight loss at 2 months was 5.5%, 9% at 6 months and 8% at 12 months.

Conclusion

Endogastric plication is a safe method, current material being unsatisfactory in many regards, because of frequent upgrades and variations regarding the advised pattern of plication. Real life results do not match those found in most publications. Still, this method represents probably the promising innovative endoscopic bariatric tool for the time being. We wish to develop a simpler and more ergonomic device that could be easily robotized. Research is going on with a new prototype called ENDOPLY, with a pilot study starting in Prague in May 2024, and pending upgrades.