bluuebunny/crossref_metadata_2025 huggingface dataset:
The effects of conical singularity and the Wu–Yang magnetic monopole on the thermodynamic properties of a harmonic oscillator interacting with a potential
Authors: Ahmed Faizuddin , Bouzenada Abdelmalek
Published: November 2024

In this work, we investigate the thermodynamic variables of a harmonic oscillator in a conical geometry metric. Moreover, we introduce an external field in the form of a Wu–Yang magnetic monopole (WYMM) and an inverse square potential into the system and analyze the results. Using an analytical approach, we obtain the energy level and study the thermodynamics at finite temperature. Our findings demonstrate that thermodynamic variables, except for the specific heat and entropy, are influenced by the topological parameters, the strength of the WYMM, and the inverse square potential.
Wavelength-tunable high-repetition-rate pulse generation in a SOA-based fiber laser with gain instability
Authors: Ivanenko A V , Bednyakova A E , Smirnov S V , Rybak A A
Published: November 2024

Introducing negative optical feedback into a semiconductor optical amplifier-based laser presents a straightforward and effective approach for generating high-repetition-rate pulses through the mechanism of self-sustaining cross-gain modulation. In this work, we demonstrate, for the first time, the tunability of high-frequency pulse generation over a wide wavelength range by adjusting the central transmission wavelength of a tunable filter. Our laser system achieved a full tuning range from 1480 nm to 1556 nm (76 nm) while maintaining pulsed lasing. Remarkably, the laser exhibited a maximum pulse contrast exceeding 85% over a tuning range of 43 nm, from 1505.7 nm to 1548.7 nm. At any wavelength within this range, stable, self-starting pulse generation was consistently achieved, with a pulse repetition rate of 1.3 GHz.
Effect of temperature on the scintillation properties of pure LaCl3 and Cs2LiYCl6:Ce crystals for neutron spectroscopy
Authors: Ahn Seon-Woo , Luan Nguyen Thanh , Vuong Phan Quoc , Nam U.W. , Kim H.J.
Published: November 2024

The Lunar Vehicle Radiation Dosimeters (LVRAD) project, run by the Korea Astronomy and Space Science Institute, is currently in the detector R&D phase. Its mission is to measure the radiation exposure experienced by astronauts on the lunar surface and to search for water and radioactive isotopes. This study focuses on inorganic scintillator R&D for neutron spectroscopy, which is essential for the LVRAD project. Two candidates, pure LaCl3 and Cs2LiYCl6:Ce enriched with 95% 6Li (CLYC-6) detectors, were investigated in this work. Though their neutron spectroscopy performance meets radiation hardness requirements, the temperature-dependent performance of the detectors needs to be clearly understood to ensure reliable operation in space. Therefore, the performance of pure LaCl3 and CLYC-6 detectors was investigated for working temperatures ranging from -30∘C to +50∘C. The dimensions of the scintillators used for measurements were Φ1.5 inch × 1.0 inch for pure LaCl3 and Φ1.5 inch × 1.5 inches for CLYC-6. Scintillation performance was measured using a Hamamatsu H7195 photomultiplier tube with a 500 MHz flash analog-to-digital converter. The detectors were operated in a large temperature and humidity chamber across a temperature range from -30∘C to +50∘C, and the temperature dependence of the pulse shape discrimination performance for fast and thermal neutrons was measured using pure LaCl3 and CLYC-6, respectively. The effect of the temperature on the absolute light yield, energy resolution, and decay times was also measured. Based on the results, the pure LaCl3 and CLYC-6 detectors proved suitable for neutron spectroscopy for the LVRAD project.
SIDDHARTA-2 apparatus for kaonic atoms research on the DAΦNE collider
Authors: Sirghi F. , Iliescu M. , Abbene L. , Amsler C. , Bazzi M. , Borghi G. , Bosnar D. , Bragadireanu M. , Buttacavoli A. , Carminati M. , Cargnelli M. , Clozza A. , Deda G. , De Paolis L. , Del Grande R. , Dulski K. , Fabbietti L. , Fiorini C. , Friščić I. , Guaraldo C. , Iwasaki M. , Khreptak A. , Manti S. , Marton J. , Moskal P. , Napolitano F. , Niedźwiecki S. , Ohnishi H. , Piscicchia K. , Principato F. , Scordo A. , Sgaramella F. , Sirghi D. , Skurzok M. , Silarski M. , Spallone A. , Toho K. , Toscano L. , Tüchler M. , Vazquez Doce O. , Zmeskal J. , Curceanu C.
Published: November 2024

SIDDHARTA-2 is a state-of-the-art experiment designed to
perform measurements of kaonic atoms, which are exotic atoms
composed of a negatively charged kaon orbiting nucleus. These atoms
constitute an exceptional probe for investigating the strong
interaction in the non-perturbative regime involving strangeness.
The experiment is installed at the DAΦNE electron-positron
collider of the INFN National Laboratory of Frascati (INFN-LNF) in
Italy, aiming to perform the first-ever measurement of the
2p → 1s X-ray transitions in kaonic Deuterium, a crucial
step towards determining the isospin-dependent antikaon-nucleon
scattering lengths. Based on the experience gained with the previous
SIDDHARTA experiment, which performed the most precise measurement
of the kaonic Hydrogen 2p → 1s X-ray transitions, the
present apparatus has been upgraded with innovative X-Ray Silicon
Drift Detectors (SDDs), distributed around a cryogenic gaseous
target placed in a vacuum chamber at a short distance above the
interaction region of the collider, two new veto systems and a
charged kaon detector. The current work presents a comprehensive
description of the SIDDHARTA-2 setup, including the optimization of
its various components during the commissioning phase of the
collider.
Design and development of smart AI-based voice assistive ergonomic commode wheelchair for mobility and rehabilitation
Authors: Kumar Naveen , Kaushal Rajesh Kumar , Verma Sanjeev , Sharma Manish , Kukreja Vinay , Pathan Sameena , Ali Tanweer
Published: November 2024

This study focuses on enhancing assistive devices for the elderly and disabled, primarily addressing the challenges associated with traditional wheelchairs. While wheelchairs are widely used for basic mobility, the research identifies several issues in existing products, such as a lack of attention to ergonomic features, anthropometric principles, and limited technological interventions. One major concern is the discomfort experienced by users over extended periods, especially when essential design elements like height and back adjustments are neglected. Another challenge highlighted is the issue of defecation, particularly in the absence of a caregiver. This dependency on caretakers can be mentally burdensome for users, raising privacy concerns during such personal activities. To address these issues, this research proposes a solution that integrates ergonomic features and incorporates low-cost technological interventions, including artificial intelligence-based voice assistance. The ultimate goal of this paper is to design and introduce an AI-based voice-assisted ergonomic wheelchair that not only supports basic mobility but also ensures comfort over extended periods. The proposed solution aims to incorporate a commode feature for defecation within a smart ergonomic wheelchair equipped with voice assistance and provide comfort to the user(s). The design prioritizes anthropometric dimensions, ensuring comfort and convenience for users across various age groups. Employing SolidWorks software, a stable and robust model has been designed, and its durability was assessed through stress analysis using the SolidWorks simulation tool by applying a 981 Newton load on the wheelchair's frame using two different materials (steel and aluminum). The maximum stress value is less than the yield strength, and the deformation is 2.57 e+00 mm for the steel frame, indicating that the design is stable and durable compared to the aluminum structure. The proposed voice-assistive, ergonomic, AI-based wheelchair with a commode cavity is a revolutionary development for the healthcare sector in terms of innovation.
Re-imagining the use of integrated assessment models from a social science perspective—lessons from the Sustainable Development Pathways (SDP)
Authors: Hernandez Ariel Macaspac , Cornell Sarah E , Keppler Dorothee , Daioglou Vassilis , Soergel Bjoern
Published: November 2024

Socio-political factors in Integrated Assessment Models (IAMs), and their scenario narratives often lack transparency for policymakers and interdisciplinary scholars. As these tools increasingly support sustainable development goals, their assumptions and methodologies require scrutiny, particularly from social scientists. We address critiques of climate isolationism, overemphasis on technological transitions, and insufficient inter- and transdisciplinarity, advocating for robust interdisciplinary integration and clearer methodological transparency. Our recommendations stem from expert interviews and over 200 stakeholders across 30 countries from 2019 to 2024, emphasizing the need for cohesive theory and comprehensive social science engagement to refine these critical tools. Our main case study uses a new scenario set, the Sustainable Development Pathways (SDPs), that made substantial efforts to address social sciences critiques. The SDPs consist of both narratives and IAM-quantified target-seeking scenarios that are supported by social science concepts and theories to ensure not only theoretical coherence, but also their credibility among policymakers. As such tools are increasingly used to facilitate policies and actions for sustainability transformation, questions are raised about how they can effectively represent the complexities behind the current polycrisis that is marked by the climate crisis, biodiversity loss, economic inequality and social injustice. The paper concludes by reflecting on the remaining challenges and open questions related to the role of exogenous sociopolitical factors, the potential for scenarios to transcend political ideologies, and the need for ongoing adaptation of SDPs to reflect the dynamic global context. It calls for continued engagement and exploration of these issues to ensure the scientific representation of sustainable and equitable futures.
Reduction of the Laplace sequence and sine-Gordon type equations
Authors: Khakimova A R , Faizulina K I
Published: November 2024

In this work, we continue the development of methods for constructing Lax pairs and recursion operators for nonlinear integrable hyperbolic equations of soliton type, previously proposed in the work of Habibullin et al (2016 J. Phys. A: Math. Theor.
49 035202). This approach is based on the use of the well-known theory of Laplace transforms. The article completes the proof that for any known integrable equation of sine-Gordon type, the sequence of Laplace transforms associated with its linearization admits a third-order finite-field reduction. It is shown that the found reductions are closely related to the Lax pair and recursion operators for both characteristic directions of the given hyperbolic equation. Previously unknown Lax pairs and recursion operators were constructed.
Hydrodynamic and mass transfer characterization of an internally illuminated airlift photobioreactor for growing Spirulina platensis
Authors: Bataller Butch G. , Capareda Sergio C.
Published: November 2024

The dimensions of the of a photobioreactor play a major role in its hydrodynamic and mass transfer characteristics that also affect its growth performance. In this study, a bench-scale airlift photobioreactor (PBR) was designed and fabricated to have a riser-to-diameter ratio (Ar/Ad) equal to 0.42 and an aspect ratio (H/D) equal to 1.53. These dimension ratios are different from typical values wherein most airlift photobioreactors are designed to have Ar/Ad of at least 1.0 and H/D of at least 2.0. It was hypothesized, based on the results of Hwang and Cheng [1], the fabricated PBR in this study will have better hydrodynamic and mass transfer characteristics such as lesser mixing time, better liquid circulation and lesser gas entrainment that may lead to better growth performance. Due to the different dimension ratios from other studies, characterization of the PBR and testing of its performance are required. The hydrodynamic and mass transfer characteristics of the fabricated airlift photobioreactor in this study were measured at varying superficial gas velocities (UGR) from 0.0017 ms−1 to 0.0124 ms−1. The growth parameters of the Spirulina platensis were then tested at different aeration rates to relate the hydrodynamic and mass transfer characteristics to the photobioreactor performance. This study has proven that a photobioreactor that is designed and operated to have the best hydrodynamic and mass transfer characteristics will have the best growth performance at the same light intensity and initial optical density.
Rare earth elements enrichment and extraction potential of bauxite deposits in Samar, Philippines
Authors: Gabo-Ratio J A , Arenque L A , Payot B , Balela M D , Vegafria M C , Guzman J , Manalo P C , Tungpalan D K
Published: November 2024

Rare earth elements (REE) play an integral part of modern life, from smartphones to satellites. Dubbed ‘critical metals’, the demand for REE has significantly increased, driven by the growth in global production for green technologies such as e-vehicles, solar panels, wind turbines, and other energy-economic infrastructure. Therefore, there is a need to explore alternative REE sources to ensure continued development of emerging green technologies. A possible alternative REE source is bauxite, which is soil that forms from intense weathering of aluminum oxide-rich rocks exposed to tropical climate. This paper investigates the REE enrichment and extraction potential from bauxite deposits in Paranas, Samar, Philippines. The sampling survey included collection of rock and soil on surface exposures, test pits, and drill cores from accessible portions of the bauxite mineral reservation site. The soil and parent rock samples collected were then subjected to various geochemical and mineralogical analyses. The main ore minerals of aluminum are gibbsite and boehmite; with minor goethite, hematite, and magnetite. Investigation of the geochemical composition of the bauxite reveals a total REE content of up to ~300 ppm, which is one of the highest REE and critical metal content among geological deposits in the country. These results will provide inputs in the design of a green and economical process to recover REE from bauxites. If the bauxite deposits prove to be a valuable REE resource, this study will help maximize the economic potential of the mineral resource in the Philippines and contribute to an economically efficient and environment-friendly way to produce e-tech elements for the country.
Production of Defragmentable Bioplastic using Starch Extracted from Annona Muricata (Soursoup) Seed Reinforced with Bentonite Nanoclay
Authors: Melendres A V , Angles S Q , Gaspar E P G , Saliendra J F , Buenaventura M M S , Sobrepeña G , Olay J G , Rubi R V C
Published: November 2024

Seeds of Annona Muricata, often called soursop or guyabano were used as a source of starch for the production of defragmentable bioplastic. The researchers used mixture of water and starch content of 10 and 20 grams respectively from Annona Muricata (soursop) seeds with various concentration (20%, 25%, 30%) of glycerol (plasticizer) and reinforced with three different concentrations (0%, 3%, 6%) of bentonite nanoclay (filler). The characterization of the bioplastic was carried out by determining the effect of variation of the ratio between the quantity of starch from soursop seeds, bentonite nanoclay, and glycerol. The starch-based defragmentable bioplastic was evaluated with its water retention, degradation, and mechanical properties. The result showed that the tensile strength improved significantly with the addition of bentonite nanoclay and the elongation at break with the addition of glycerol. Same way in water retention test, where the presence of the bentonite nanoclay increased the strength of the bioplastic with its water solubility. In soil burial test, a higher level of glycerol concentration increased the rate of the bioplastic degradation. By adding the bentonite nanoclay as a filler, the rate of bioplastic degradation decreased compared to the bioplastic without filler. In shelf-life test, adding glycerol as plasticizer improved the shelf life of bioplastics. A high concentration of glycerol served as an anti-fungal for bioplastics.
Production of few-layer graphene and boron nitride nano onions via lamp ablation
Authors: He J. , Zhang H. , Zhang W. , Gordon J. M. , Chua H. T.
Published: November 2024

Few-layer graphene, and separately, boron nitride nano onions have been synthesised by a novel lamp ablation method which is a one-step, high-yield process that is catalyst-free, devoid of toxic reagents, with short reaction times, and potentially scalable. The precursor for the few-layer graphene is graphite flake, while that of boron nitride nano onions is hexagonal boron nitride powder. Product nanostructures are characterised by high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDS) and electron energy loss spectroscopy (EELS). We also report on our commercialisation trajectory to translate promising research findings in the laboratory to the market. For the few-layer graphene product, it is presently on a pre-commercial pilot plant phase.
Application of Dynamic Simulation for the Design of the LNG Inlet Gas Compressor Anti-Surge Protection
Authors: Soriano K M , Muñoz J C
Published: November 2024

An inlet gas compressor system is simulated in Aspen HYSYS Dynamics v12.1. The emphasis of the simulation is to design the system to prevent or mitigate surges during an emergency shutdown (ESD). The dynamic simulation aims to assess the performance of the anti-surge control valve (ASCV), to add and size a cold gas bypass valve (CGBV) or hot gas bypass valve (HGBV) if the ASCV is insufficient, to determine the corresponding bypass valve size, and to select which bypass valve configuration is appropriate. An ASCV accompanied by an 8” HGBV is shown to be the recommended anti-surge protection configuration to mitigate surge due to its faster response and is more appropriate for motor-driven compressors which slow down more quickly during ESD. The ASCV provided by the compressor vendor with the recommended 8” HGBV can mitigate the effects of compressor surges during an emergency shutdown scenario.
Removal of tetracycline from aqueous solution via Fenton process using iron-impregnated bamboo biochar
Authors: Calangi J D , Borres J L , Grande M K P F , Ong D C , Malones J M C
Published: November 2024

Tetracycline (TC) is a pharmaceutical that has been used extensively that its presence in water sources causes detriment to both aquatic life and human health. TC is not completely removed in wastewater treatment processes and could enter the environment through effluent and sludge. This study evaluated the potential of iron-impregnated bamboo biochar (Fe-biochar) as catalyst in the removal of tetracycline from aqueous solution via Fenton process. Characterization via Fourier transform infrared (FTIR) and energy dispersive X-ray spectroscopy (EDX) analyses verified the successful iron impregnation on biochar. TC removal was determined at 357nm absorbance through UV-Visible spectroscopy. Highest TC removal of 63.24% was achieved under conditions of 75 mg Fe-biochar, 0.45 M H2O2, and pH 5. Experimental data were assessed using the three factors Box-Behnken response surface experimental design where Fe-biochar dosage, H2O2 concentration, and solution pH were found to be significant parameters in TC removal. Furthermore, it was determined that the data fitted well in a reduced-cubic model with high coefficient of determination (R2 = 0.9990) which indicates good regression. The optimum conditions were found to be 39.44 mg Fe-biochar dosage, 0.05 M H2O2, and pH 4, with TC removal efficiency of 33.90%. Overall, the results of this study suggested that Fe-impregnated bamboo biochar can be used as an effective catalyst in removing tetracycline from aqueous solution via heterogeneous Fenton process.
Selection of Solar-Based Water-Splitting Hydrogen Production and Hydrogen Storage Technologies Using Neutrosophic Analytic Hierarchy Process and Neutrosophic Complex Proportional Assessment
Authors: Oseña R , Merto J , Tayona S , Rustia G
Published: November 2024

The production of hydrogen through water-splitting using solar energy has the potential to meet the world’s future energy demand while also addressing the issue of greenhouse gas emissions. To compare and select the best technology among solar thermochemical cycles, photoelectrochemical, and photocatalytic water-splitting in terms of solar-to-hydrogen efficiency, production cost, safety, life expectancy, maintenance cost, and detrimental impact on the environment, this study used a multi-criteria decision analysis hybrid called Neutrosophic Analytic Hierarchy Process (NAHP) and Neutrosophic Complex Proportional Assessment (NCOPRAS). The same method was used to determine the best technology for automobiles among compressed hydrogen storage, metal hydrides, metal-organic frameworks, and chemical storage in terms of gravimetric system capacity, volumetric system capacity, safety, system cost, cycle life, energy efficiency, detrimental impact on the environment, and refueling time. There were 4 experts each in hydrogen storage and hydrogen, specifically from the Philippines, Australia, India, Romania, and Italy. All experts’ judgments have a consistency ratio (CR) < 0.1. The priority criterion for hydrogen production was life expectancy (weighted value (WV) = 0.189), and gravimetric system capacity for hydrogen storage (WV = 0.137). The result showed that among all alternatives for hydrogen production, the solar thermochemical cycle was the best (relative significance value (RSV) = 0.3432) as for hydrogen storage, the best technology among the alternatives was metal hydrides (RSV = 0.2575). A sensitivity analysis was used to check the variability and robustness of the solution.
Conversion of polypropylene (PP) plastic waste to liquid oil through catalytic pyrolysis using Philippine natural zeolite
Authors: Bautista Angelica S , Rivera Karl Nikolai O , Suratos Trixie Anne Kimberly M , Dimaano Maria Natalia R
Published: November 2024

The accumulation of plastic waste compelled the need to develop energy recovery methods, such as pyrolysis, which could convert plastics into valuable energy sources. Pyrolysis requires high operating temperatures; thus, a catalyst is often utilized to speed up the process. In this study, the viability of Philippine Natural Zeolite (PNZ) as a catalyst was investigated through the conversion of polypropylene (PP) waste into liquid oil using catalytic pyrolysis. The PP waste feedstocks were pre-mixed with the PNZ in a 1:10 ratio. Pyrolysis was carried out in a heating mantle for three trials of non-catalytic and catalytic pyrolysis. SEM and XRD were conducted to characterize the PNZ, while FTIR was carried out for the pyrolysis oil. SEM analysis showed the voids formed from the pores of the catalyst that influenced the pyrolysis reaction. Results from the XRD pattern also revealed clinoptilolite, mordenite, and heulandite as the main minerals found in the PNZ. Non-catalytic pyrolysis of PP yielded an average of 75.03% liquid oil, 13.66% residue, and 11.31% uncondensed gas. Meanwhile, catalytic pyrolysis produced higher yields with 86.39% liquid oil, 12.49% residue, and 1.12% uncondensed gas. FTIR results exhibited clear peaks for both processes, with similar components but different intensities.
Integration of bioprinting advances and biomechanical strategies for in vitro lung modelling
Authors: Avery Kathryn , Chen Xiongbiao
Published: November 2024

The recent occurrence of the Covid-19 pandemic and frequent wildfires have worsened pulmonary diseases and raised the urgent need for investigating host-pathogen interactions and advancing drug and vaccine therapies. Historically, research and experimental studies have relied on two-dimensional cell culture dishes and/or animal models, which suffer from physiological differences from the human lung. More recently, there has been investigation into the use of lung-on-a-chip models and organoids, while the use of bioprinting technologies has also emerged to fabricate three-dimensional constructs or lung models with enhanced physiological relevance. Concurrently, achievements have also been made to develop biomimetic strategies for simulating the in vivo biomechanical conditions induced by lung breathing, though challenges remain with incorporating these strategies with bioprinted models. Bioprinted models combined with advanced biomimetic strategies would represent a promising approach to advance disease discovery and therapeutic development. As inspired, this article briefly reviews the recent progress of both bioprinted in vitro lung models and biomechanical strategies, with a focus on native lung tissue microstructure and biomechanical properties, bioprinted constructs, and biomimetic strategies to mimic the native environment. This article also urges that the integration of bioprinting advances and biomimetic strategies would be essential to achieve synergistic effects for in vitro lung modelling. Key issues and challenges are also identified and discussed along with recommendations for future research.
Experimental investigation on high heat flux plasma parameters of HIT-PSI device in argon discharges
Authors: HUANG 黄 Tao 韬 , NIE 聂 Qiuyue 秋月 , CHEN 陈 Cheng 晟 , NIE 聂 Lin 林 , ZHAO 赵 Wei 伟 , JIANG 姜 Tao 涛 , LIU 刘 Yang 洋 , ZHAO 赵 Xu 旭 , LI 李 Feng 丰 , WANG 王 Xiaogang 晓钢
Published: November 2024

Researches on plasma-facing materials/components (PFMs/PFCs) have become a focus in magnetic confinement fusion studies, particularly for advanced tokamak operation scenarios. Similarly, spacecraft surface materials must maintain stable performance under relatively high temperatures and other harsh plasma conditions, making studies of their thermal and ablation resistance critical. Recently, a low-cost, low-energy-storage for superconducting magnets, and compact linear device, HIT-PSI, has been designed and constructed at Harbin Institute of Technology (HIT) to investigate the interaction between stable high heat flux plasma and PFMs/PFCs in scrape-off-layer (SOL) and divertor regions, as well as spacecraft surface materials. The parameters of the argon plasma beam of HIT-PSI are diagnosed using a water-cooled planar Langmuir probe and emission spectroscopy. As magnetic field rises to 2 T, the argon plasma beam generated by a cascaded arc source achieves high density exceeding 1.2×1021 m−3 at a distance of 25 cm from the source with electron temperature surpassing 4 eV, where the particle flux reaches 1024 m−2s−1, and the heat flux loaded on the graphite target measured by infrared camera reaches 4 MW/m2. Combined with probe and emission spectroscopy data, the transport characteristics of the argon plasma beam are analyzed.
The unbounded denominators conjecture
Authors: Calegari Frank , Dimitrov Vesselin , Tang Yunqing
Published: November 2024

We prove the unbounded denominators conjecture in the theory of noncongruence modular forms for finite index subgroups of

SL
2

⁡
(

Z

)

\operatorname {SL}_2(\mathbf {Z})

. Our result includes also Mason’s generalization of the original conjecture to the setting of vector-valued modular forms, thereby supplying a new path to the congruence property in rational conformal field theory. The proof involves a new arithmetic holonomicity bound of a potential-theoretic flavor, together with Nevanlinna second main theorem, the congruence subgroup property of

SL
2

⁡
(

Z

[
1

/

p
]
)

\operatorname {SL}_2(\mathbf {Z}[1/p])

, and a close description of the Fuchsian uniformization

D
(
0
,
1
)

/

Γ
N

D(0,1)/\Gamma _N

of the Riemann surface

C

∖

μ
N

\mathbf {C} \smallsetminus \mu _N

.
Hard Lefschetz property for 𝕊³-actions
Authors: Royo Prieto José Ignacio , Saralegi-Aranguren Martintxo , Wolak Robert
Published: November 2024

The Hard Lefschetz Property (HLP) has recently been formulated in the context of isometric flows without singularities on manifolds. In this category, two versions of the HLP (manifold and transverse) have been proven to be equivalent, thus generalizing the results in the important classes of K-contact and Sasakian manifolds. In this paper we define both versions of the HLP for almost-free

S

3

\mathbb {S}^3

-actions, and prove that they agree for actions satisfying a cohomological condition, which holds in the important category of 3-Sasakian manifolds, where those two versions of the HLP are shown to be true. We also provide a family of examples of free actions of the 3-sphere which are not 3-Sasakian manifolds, but satisfy the HLP.
A generalized health index: automated thoracic CT-derived biomarkers predict life expectancy
Authors: Beeche Cameron , Yu Tong , Wang Jing , Wilson David , Chen Pengyu , Duman Emrah , Pu Jiantao
Published: November 2024

Objective

To identify image biomarkers associated with overall life expectancy from low-dose CT and integrate them as an index for assessing an individual’s health.

Methods

Two categories of CT image features, body composition tissues and cardiopulmonary vasculature characteristics, were quantified from LDCT scans in the Pittsburgh Lung Screening Study cohort (n = 3635). Cox proportional-hazards models identified significant image features which were integrated with subject demographics to predict the subject’s overall hazard. Subjects were stratified using composite model predictions and feature-specific risk stratification thresholds. The model’s performance was validated extensively, including 5-fold cross-validation on PLuSS baseline, PLuSS follow-up examinations, and the National Lung Screening Trial (NLST).

Results

The composite model had significantly improved prognostic ability compared to the baseline model (P < .01) with AUCs of 0.774 (95% CI: 0.757-0.792) on PLuSS, 0.723 (95% CI: 0.703-0.744) on PLuSS follow-up, and 0.681 (95% CI: 0.651-0.710) on the NLST cohort. The identified high-risk stratum were several times more likely to die, with mortality rates of 79.34% on PLuSS, 76.47% on PLuSS follow-up, and 46.74% on NLST. Two cardiopulmonary structures (intrapulmonary artery-vein ratio, intrapulmonary vein density) and two body composition tissues (SM density, bone density) identified high-risk patients.

Conclusions

Body composition and pulmonary vasculatures are predictive of an individual’s health risk; their integrations with subject demographics facilitate the assessment of an individual’s overall health status or susceptibility to disease.

Advances in knowledge

CT-computed body composition and vasculature biomarkers provide improved prognostic value. The integration of CT biomarkers and patient demographic information improves subject risk stratification.
Assessing the performance of ChatGPT and Bard/Gemini against radiologists for Prostate Imaging-Reporting and Data System classification based on prostate multiparametric MRI text reports
Authors: Lee Kang-Lung , Kessler Dimitri A , Caglic Iztok , Kuo Yi-Hsin , Shaida Nadeem , Barrett Tristan
Published: November 2024

Objectives

Large language models (LLMs) have shown potential for clinical applications. This study assesses their ability to assign Prostate Imaging-Reporting and Data System (PI-RADS) categories based on clinical text reports.

Methods

One hundred consecutive biopsy-naïve patients’ multiparametric prostate MRI reports were independently classified by 2 uroradiologists, ChatGPT-3.5 (GPT-3.5), ChatGPT-4o mini (GPT-4), Bard, and Gemini. Original report classifications were considered definitive.

Results

Out of 100 MRIs, 52 were originally reported as PI-RADS 1-2, 9 PI-RADS 3, 19 PI-RADS 4, and 20 PI-RADS 5. Radiologists demonstrated 95% and 90% accuracy, while GPT-3.5 and Bard both achieved 67%. Accuracy of the updated versions of LLMs increased to 83% (GTP-4) and 79% (Gemini), respectively. In low suspicion studies (PI-RADS 1-2), Bard and Gemini (F1: 0.94, 0.98, respectively) outperformed GPT-3.5 and GTP-4 (F1:0.77, 0.94, respectively), whereas for high probability MRIs (PI-RADS 4-5), GPT-3.5 and GTP-4 (F1: 0.95, 0.98, respectively) outperformed Bard and Gemini (F1: 0.71, 0.87, respectively). Bard assigned a non-existent PI-RADS 6 “hallucination” for 2 patients. Inter-reader agreements (Κ) between the original reports and the senior radiologist, junior radiologist, GPT-3.5, GTP-4, BARD, and Gemini were 0.93, 0.84, 0.65, 0.86, 0.57, and 0.81, respectively.

Conclusions

Radiologists demonstrated high accuracy in PI-RADS classification based on text reports, while GPT-3.5 and Bard exhibited poor performance. GTP-4 and Gemini demonstrated improved performance compared to their predecessors.

Advances in knowledge

This study highlights the limitations of LLMs in accurately classifying PI-RADS categories from clinical text reports. While the performance of LLMs has improved with newer versions, caution is warranted before integrating such technologies into clinical practice.
BS O02 - Impact of Bariatric surgery on Obesity Indices and Reproductive Hormones: A Prospective Study in Morbidly Obese Women
Authors: Bananis Kyriakos , Almoshantaf Mohammad Badr
Published: November 2024

Background

Obesity, defined by a BMI of 30 kg/m² or higher, is influenced by genetics, socio-economic, and cultural factors. Genetic predispositions affect metabolism and energy regulation, while environmental factors like sedentary lifestyles and poor food environments worsen obesity. Obesity disrupts hormonal balances, impacting sex hormone levels and menstrual cycles, leading to infertility in women. This hormonal imbalance affects oocyte quality and ovulation. Bariatric surgery offers significant weight loss and metabolic improvements, enhancing reproductive hormone profiles and insulin sensitivity. Our study explores how sleeve gastrectomy affects BMI and hormone levels, aiming to understand its impact on obesity management and reproductive health.

Method

This prospective observational study examines the effects of laparoscopic sleeve gastrectomy on reproductive hormones and ovarian function in 32 morbidly obese women, adhering to Helsinki Declaration ethics. Participants, aged 18-50 with no menopause or chronic illness, consented to the study. Exclusions included those with polycystic ovary syndrome, recent reproductive organ surgery, or recent infertility medications. The study assessed changes in BMI, antral follicles, anti-Müllerian hormone, and reproductive hormones before surgery and at 6 and 12 months post-surgery. Blood samples and transvaginal ultrasounds were conducted preoperatively and at 6 and 12 months postoperatively to monitor outcomes.

Results

The study involved participants with an average age of 33 and a mean BMI of 42.12. Significant changes were observed post-sleeve gastrectomy at 6 and 12 months (p < 0.001). At 6 months, BMI decreased by 9.24 units, AMH levels dropped from 3 to 2.5 ng/mL, and antral follicle counts in both ovaries declined. By 12 months, BMI decreased by 16.47 units, AMH levels fell to 2 ng/mL, and antral follicle counts further reduced. Hormonal changes included increases in FSH, LH, and estradiol, while SHBG levels rose, and free testosterone levels decreased significantly.

Conclusion

Individual hormone responses to weight loss and surgery necessitate personalized obesity treatments. Tailoring surgical approaches and care to hormonal profiles can optimize outcomes and reduce complications. Monitoring AMH levels post-surgery can offer insights into reproductive effects, aiding clinical management and counseling for women with obesity-related infertility. We highlight the significant impact of sleeve gastrectomy on physiological parameters in obese individuals, especially regarding reproductive health and metabolic regulation. The findings enhance understanding of the changes associated with bariatric surgery and its potential benefits for metabolic and reproductive health.
BN O01 - Hiatus hernia and gastro-oesophageal reflux disease. Does size matter?
Authors: Barghash Mohammed , Obayi Emmanuel , Itaman Usifoh , Furber Zoe , Caul Amy , Othman Ahmad , Mansour Moustafa
Published: November 2024

Background

Hiatus hernia occurs when part of the stomach bulges into the thoracic cavity through the hiatal opening of the diaphragm. In our study, we aimed to assess the impact of the hiatal hernia size on DeMeester score, symptom correlation, and presence of pathological reflux on PH studies. The study also looked at the impact of various characteristics including age, smoking, alcohol consumption, body mass index (BMI), and presence of oesophagitis and/or dysmotility on DeMeester score, symptom correlation, and presence of pathological reflux on PH studies.

Method

The study was conducted in an Upper Gastrointestinal surgery unit located in the North West of England. All patients aged over 18 who underwent laparoscopic fundoplication for gastro-oesophageal reflux disease between January 2017 and June 2023 were included. Patients who underwent fundoplication for para-oesophageal hiatus hernia, those who had fundoplication as a complementary step to Heller’s cardio-myotomy, or those who underwent revisional surgery were excluded.

Results

A total of 115 patients with a median age of 54 were included. Patients’ age was found to have a statistically significant association with hiatus hernia size above 2 cm, DeMeester score, and Symptom Association Probability with a P value of 0.011, 0.021, and 0.030 respectively. Hiatus hernia size above 2 cm was found to have a statistically significant association with pathological reflux (P=0.017). Smoking association with DeMeester score was found to be significant (P=0.027). Hiatus hernia size was not found to have a statistically significant association with DeMeester score, Symptom Index, or Symptom Association Probability (P=0.115, 0.315, 0.904) respectively.

Conclusion

Hiatus hernia size above 2 cm was found to have a statistically significant association with pathological reflux on PH studies but not statistically associated with elevated DeMeester score above 14.72 or symptom correlation indices. Thorough endoscopic assessment in addition to detailed oesophageal physiological studies are mandatory to evaluate patients with gastro-oesophageal reflux disease prior to considering surgery.
BN O02 - Introducing the Cholecystectomy Urgency Index (CUI) – A novel way to visualise and optimise the waiting list for laparoscopic cholecystectomy at a large district general hospital
Authors: Allan Charlotte , Whitehead-Clarke Thomas , Nadeem Tehmina , Muthukumaru Yogeswaran , Yaqub Haseeb , Nehra Dhiren
Published: November 2024

Background

Gallstone disease effects approximately 10-15% of the adult population, and laparoscopic cholecystectomy is one of the most common surgical procedures in the UK, with over 60,000 performed each year. Delays to surgery from diagnosis has been found to increase patient morbidity and readmission rate. Waiting lists in the UK have been struck with a significant backlog from the COVID-19 pandemic, and navigating this ever-expanding patient population to determine priority for booking cases is complex. We propose a new system to prioritise and visualise this cohort of patients in real time – the Cholecystectomy Urgency Index.

Method

At one large district general hospital, we had a waiting list of 148 patients for laparoscopic cholecystectomy. We identified the individual underlying pathology and established the waiting time since diagnosis to allocation of operative date.

We used excel to formulate a pairwise scatter plot of the waiting list patients based upon the time waiting. We were able then to colour code them based on pathology (biliary colic/cholecystitis/cholangitis/pancreatitis/obstructive jaundice). We were then able to link this directly to our scheduling to create a live, visual representation of our waiting list, by both days waited and causative pathology.

Results

We found our median wait times for patients varied based on pathology: Biliary Colic = 185 days, Cholecystitis = 57 days, Pancreatitis, Cholangitis and Obstructive Jaundice (OJ) = 65 days.

We found that the pairwise scatter plot provided a rapidly accessible, easily identifiable visual representation of our patient cohort by both days waited and diagnosis.

This allows relevant staff, surgeons and schedulers to plan elective cases according to both urgency and time waited. Long waiters are easily identified as outliers on the graph and can therefore be flagged for last minute cancellation slots.

Conclusion

By using this system, we can optimise our waiting lists, improve productivity and patient outcomes. We propose a system to enable this further when booking patients: to give them a colour coded CUI number of 1-3. 1 being biliary colic, 2 – cholecystitis, 3 – pancreatitis/cholangitis/OJ.

This will be directly linked to our scatter graph and in doing so, provides us with a readily available, live snapshot in time of the current wait list. This system allows for both clinical urgency prioritisation and easy visualisation of patient cohorts, thus catalysing the elimination of long waiters by means of clear identification.
BN O04 - Trends in the management of bile duct stones in the United Kingdom: Are we following the evidence?
Authors: Brown Oliver D , Aroori Somaiah
Published: November 2024

Background

Common bile duct stones (CBDS) are typically managed in two stages: Endoscopic Retrograde Cholangiopancreatography (ERCP) followed by laparoscopic cholecystectomy (LC). However, access to ERCP can be limited or require referral, has a high failure rate, often necessitates additional imaging, and may involve multiple procedures. Increasing evidence suggests that single-stage management, involving LC with intraoperative imaging and bile duct exploration when indicated, is cheaper, more effective, and reduces overall length of stay. British Society of Gastroenterology guidance states that it is a valid alternative to ERCP. This study aimed to determine whether clinical practice aligns with this evidence.

Method

National Health Service (NHS) Admitted Patient Care publications summarise Hospital Episode Statistics by financial year and are openly accessible. OPCS4 Procedure Codes were screened by two authors and categorised as “operative” or “endoscopic.” Codes detailing the management of CBDS or bile duct exploration were included, while ambiguous codes or those for non-stone indications were excluded. Data pertaining to these codes were extracted from the Admitted Patient Care publications for 2012 to 2022 and summarised in a Microsoft Excel spreadsheet. Trends were analysed using a Non-Seasonal Mann-Kendall Trend Test

Results

A total of 249,475 procedures for CBDS were performed over the ten-year period, with a mean patient age of 67. Annually, the total number of procedures increased from 21,365 to 27,668 (p=0.002). Endoscopic procedures increased from 19,716 to 25,976 (p=0.002), while operative procedures remained stable (1,649 to 1,692, p=0.431). Consequently, the proportion of endoscopic management rose from 92.3% to 93.9% (p<0.001). The mean age of patients undergoing operative procedures was ten years younger than those undergoing endoscopic procedures (57 vs. 67 years)

Conclusion

Despite evidence and guidance supporting single-stage procedures, there is a trend towards endoscopic management of CBDS in the UK. This may be due to operational pressures on the NHS, including the sequelae of the COVID-19 pandemic, or reflect challenges within hospital culture, skill mix, or equipment availability.
HPB O03 - Snapshot Audit of RELEVANCE: REal worLd outcomEs of adjuVant therapy in pANcreatic CancEr
Authors: Alfarah Jameel , Halle-Smith James , Roberts Keith
Published: November 2024

Background

Evidence-based medicine plays a critical role in shaping clinical practices and setting patient expectations. While randomized controlled trials (RCTs) of adjuvant chemotherapy in pancreatic cancer have demonstrated improved survival rates with newer regimens, their selective inclusion criteria often favor patients with better prognoses. This study aims to compare real-world outcomes with those from RCTs to evaluate the effectiveness of adjuvant therapies in typical clinical settings.

Method

In this retrospective study, we examined overall survival (OS) among patients who received adjuvant chemotherapy (gemcitabine, gemcitabine-capecitabine, or FOLFIRINOX) following the resection of pancreatic ductal adenocarcinoma. We compared survival curves from RCTs (ESPAC 4, PRODIGE-24) with those from real-world cohorts selected based on RCT criteria. Data were collected retrospectively from medical records and institutional databases, covering OS, disease-free survival (DFS), and adverse events.

Results

From July 2014 to December 2019, 303 pancreatic ductal adenocarcinoma patients underwent resections, with 209 (69%) receiving adjuvant chemotherapy: 91 (44%) received gemcitabine, 69 (34%) gemcitabine-capecitabine, and 37 (18%) FOLFIRINOX. The median OS for gemcitabine was 21.6 months, close to ESPAC 4’s 25.5 months. Gemcitabine-capecitabine had a median OS of 25.2 months versus ESPAC 4’s 28 months. FOLFIRINOX had a lower median OS in our cohort (19.9 months) compared to PRODIGE 24’s 54.4 months. Additionally, gemcitabine OS in PRODIGE 24 was higher (35 months) than in our data. FOLFIRINOX had a 17% completion rate.

Conclusion

The real-world outcomes for gemcitabine-based adjuvant therapy align closely with RCT results, while FOLFIRINOX appears less effective in typical clinical settings, possibly due to tolerance issues. These findings highlight the importance of incorporating real-world data in clinical decision-making to better predict patient outcomes and improve treatment strategies for pancreatic cancer. Further research is needed to bridge the gap between RCTs and real-world practices, especially concerning patient selection and treatment tolerability.
MS O04 - OGC Outcomes following gastrectomy for cancer: A 15-Year Retrospective Study examining the impact of regional service centralisation, benchmarking against international standards
Authors: Worthington Lucy , Waheed Unazia , Thirunavaya Kalathil Mohamed Abdullatheef , Al-Daghri Khalid , Alkhaffaf Bilal
Published: November 2024

Background

Gastrectomy remains the cornerstone of curative treatment for gastric cancer but is associated with significant risks of complications. This study aimed to explore the impact of service centralisation in Greater Manchester on outcomes following gastrectomy for cancer. Outcomes were compared against international benchmarks to evaluate impact of centralisation and identify areas for improvement.

Method

This was a retrospective study of all patients undergoing gastrectomy (total gastrectomy TG; partial gastrectomy PG) for cancer at a tertiary OG cancer centre between 2007-2022. Patients were allocated to three time periods (2007-2012; 2013-2018; 2018-2022). Regional centralisation took place in August 2018. Outcome selection was guided by a core outcome set for gastrectomy and international benchmarks including the GastroData consortium and the Dutch Upper Gastrointestinal Cancer Audit (DUCA).

Results

379 patients undergoing gastrectomy (TG; 201, PG; 172) were included. Median length of stay shortened (p=0.023) and median lymph node yield improved (p<0.001) following centralisation. This was consistent with findings from the DUCA audit. There was no difference in R0 resection rates (p=0.668), surgical reinterventions (p=0.717) or readmissions within 90-days (p=0.428) after centralisation. Whilst post-operative mortality improved (30-day 4.5% versus 0%; 90-day 5.4% versus 1.2%), this was not statistically significant (p=0.09).

Conclusion

Centralisation of surgical OG cancer services in our region resulted in improved short-term outcomes for patients undergoing gastrectomy. This may reflect a greater emphasis on standardised peri-operative surgical and pathology protocols. These findings were partly consistent with international benchmarks. Further evaluation of the impact on longer-term outcomes is required.