bluuebunny/crossref_metadata_2025 huggingface dataset:
First injector commissioning results with helium beam at MedAustron Ion Therapy Center
Authors: Gambino Nadia , Kausel Matthias , Guidoboni Greta , Penescu Liviu , Rizzoglio Valeria , Schmitzer Claus , Kurfürst Christoph
Published: April 2022

MedAustron is a synchrotron-based Particle Therapy Accelerator located in lower Austria which delivers clinical proton and carbon beams in the range of 62-252.7 MeV/u and 120-400 MeV/u respectively in two clinical treatment rooms. A proton Gantry was recently commissioned in a third clinical treatment room and a fourth experimental beamline is dedicated to non-clinical research activities. Within the latter, the injector commissioning has recently started for He2+ beam generation. The long-term goal is to use helium for cancer treatment due to its favourable physical and biological properties. The helium beam properties from the source up to injection further downstream into the accelerator, i.e. from the Low Energy Beam Transfer line to the Linear Accelerator are discussed in terms of beam emittance, intensity and transmission efficiency. Furthermore, a comparison with simulated data is presented.
Load Allocation of Biomass Cogeneration Units Based on Multi-objective Optimization Algorithm
Authors: Xiao Ying , Wang Yufang
Published: April 2022

The optimal allocation of biomass thermoelectric loads is a multi-objective, multi-constrained optimisation mathematical model based on the biomass fuel consumption and environmental performance of the unit. The thermoelectric loads are allocated rationally between operating units to minimise the total biomass fuel consumption overall, subject to the constraints of meeting user requirements and unit operating times. The multi-objective optimisation algorithm was used to investigate the optimal allocation of the material thermoelectric load. The calculation results show that the method is simple and convenient and can reasonably allocate the heating load and power generation load of each unit, effectively reducing the overall biomass energy consumption and thus achieving energy saving.
Numerical Simulation Research of Excavation Based Enhanced Geothermal System
Authors: Li Yu , Ma Ke , Li Hong , Tao Ye , Liu Guoyang
Published: April 2022

Under the premise that the global fossil energy is decreasing, geothermal energy has entered the public view with its huge reserves. Geothermal energy can supply energy stably and uninterruptedly without being restricted by factors such as seasons climates, sunlight changes, and has broad development potential. This paper introduces a new deep geothermal development model—Excavation Based Enhanced Geothermal System (EGS-E). The innovative excavation based EGS-E scheme uses mining techniques to form deep underground access for creating artificial heat reservoir with multi-level fracture networks using excavation, blasting, and caving. The working water enters the heat exchange pool through the shaft for heat exchange. Different from the traditional geothermal model, this model can form an ultra-large volume, high permeability heat source and stable heat storage due to its special structure. In this study, a steady-state 3D model was established to study the heat exchange, temperature at the water outlet, and pressure distribution at the central section of the excavation based enhanced geothermal system (EGS-E). The results show that: when the inlet fluid velocity increases from static to 100m/s, the average outlet fluid temperature decreases from 473.15K to 360K. The heat production is better than that of EGS-D, and it is an ideal alternative to the existing EGS
Study on the Influence of the Cavitation of the Feedwater Pump in the Nuclear Power Unit Cogeneration Mode
Authors: Gao Ning , Shao Jiaye , Geng Tao , Xing Zhaokai , Song Ze
Published: April 2022

This paper conducts modeling and simulation of a nuclear power cogeneration unit system, and analyzes the impact of feedwater pump cavitation through important transient conditions such as steam turbine tripping, load rejection, and feedwater pump tripping. The simulation results show that cogeneration The influence of the mode on the NPSH of the feedwater front pump is generally not large, and the NPSH of the feedwater front pump is slightly improved in all working conditions. Provide a reference for the safe and stable operation of nuclear power cogeneration units.
Optimal power flow calculation of UPFC power system based on PSAT
Authors: Hu Yuan , Wu Peng , Xing Lin , Zhang Shuai , Wang Ning , Li Yan , Zhao Penghui , Wang Shuo
Published: April 2022

With the continuous improvement of the accuracy of power grid equipment components, the flexible control of unified power flow controller can better improve the stability of power grid. The continuous deepening of UPFC research meets the development needs of new power systems. Simulation analysis in PSAT environment can better study the power flow calculation of UPFC. In this paper, an improved power injection model is proposed for power flow calculation, and the optimal power flow is solved by the stability of power system and the economy of power market. The ieee9 node system is modeled, and the simulation calculation method is compared with BP neural network. The results are close, which shows that the PSAT analysis has high accuracy.
Dynamic Monitoring Method of Enterprise Power Consumption Based on Energy Big Data
Authors: Guo Jiangtao , Li Yajie , Fan Mao , Ma Wanzhen
Published: April 2022

With the global shortage of resources and energy and the intensification of environmental pollution, the problems of energy consumption and pollution emission in the manufacturing industry have become increasingly prominent. Green development, quality improvement and efficiency increase have gradually become an important development trend of the manufacturing industry. Green manufacturing engineering must be vigorously constructed and developed. Discrete manufacturing is characterized by discontinuous processes. The manufacturing process is accompanied by a large amount of primary energy consumption and environmental emissions. Compared with process manufacturing, discrete manufacturing process control is more complex and changeable, its green development level needs to be improved, and the implementation process is more difficult. As one of the common workshops in discrete manufacturing, NC workshop has problems such as high energy consumption. Based on the above reasons, this paper takes the energy-saving optimization and energy management of discrete manufacturing enterprises as the research goal, and carries out the research on energy-saving optimization and energy management system for NC workshop. It is of great significance to reduce the energy consumption of NC workshop, improve the energy utilization efficiency, solve the pain points of many enterprise information islands and difficult to control energy consumption, and improve the green level of production process in discrete manufacturing enterprises.
Optimization of synthetic conditions of explosive emulsifier Span 80
Authors: Gu Guizhou , Zhang Tao , Jiang Linshi , Li Zheng
Published: April 2022

In this paper, the effects of the two-step synthesis process on the acid value, saponification value and hydroxyl value of the samples, such as the molar ratio of Span 80 sorbitol to industrial oleic acid, the amount of catalyst used in etherification and esterification stages, reaction temperature and reaction time were studied. The results showed that 200g of sorbitol and 500g of industrial oleic acid had a vacuum degree of 0.085 MPa in the etherification stage, phosphoric acid with a mass concentration of 0.5% was used as catalyst in etherification stage, and the reaction time was 2 h with a gradient temperature rise of 150 °C; for esterification stage, NaOH solution with a mass concentration of 0.6% was used as catalyst, and the gradient temperature rise formula was 220 °C, and the reaction time was 2.5 h with a final quench method to obtain high-quality Span 80 had an acid value of 1.781 mgKOH/g, a hydroxyl value of 201.136 mgKOH/g and a saponification value of 152.614 mgKOH/g, which conforms to the national standard of high quality Span 80.
Optimal design of energy-taking power supply based on AC electric field induction
Authors: Liu Hongwei , Li Yufu
Published: April 2022

AC electric field induction based energy extraction power supply is a new power supply method for the on-line monitoring device of transmission lines, but because of its low output power, it is difficult to meet the electricity demand of the on-line monitoring device. In order to solve this problem, a new induction electrode structure is proposed based on the theoretical analysis of the factors affecting the energy taking power, and the simulation analysis and experimental verification are carried out. The results show that the designed induction electrode can generate a displacement current of 3.35mA at 10kV voltage level, and the power output can be more than 600mW when the load resistance is greater than 5kΩ. The principle and method of this paper provide a new idea for solving the power supply problem of on-line monitoring device.
Research on Safety Evaluation Method of Hydrogen Diaphragm Compressor Based on Multi-Model Weighted Combination
Authors: Shu Yue , Liu Xiaoming , Mao Chaopeng , Yu Yang
Published: April 2022

By establishing a remote monitoring system for the hydrogen diaphragm compressor, the thermodynamic real-time performance parameters of the unit are obtained. Using the multi-model weighted combination method, the safety evaluation system of hydrogen diaphragm compressors is established, and the risk assessment and safety evaluation analysis of three hydrogen diaphragm compressors are carried out. The analysis and calculation results show that the three hydrogen diaphragm compressors are all within the rating range of safe operation, which verifies that the multi-model weighted combination is a high-precision unit safety evaluation method, which can be used to evaluate the safe operation status of the hydrogen diaphragm compressor, so as to ensure the long-term safe and stable operation of the pressurized equipment of the hydrogen refueling station.
Research on improved sparrow algorithm based on random walk
Authors: Xie Shaohua , He Shan , Cheng Jing
Published: April 2022

The optimization problem is a hot issue in today’s science and engineering research. The sparrow algorithm has the advantages of simple structure, few control parameters and high solution accuracy, and has been widely used in the research of optimization problems. Purposing at the problem that the sparrow search algorithm (SSA) can’t take into account the global and local optimization, an improved sparrow algorithm based on random walk strategy is proposed. After the sparrow search, the random walk is used to perturb the optimal sparrow to demonstrate its search-ability. At the original of the iteration, the random walk boundary is large, which is favourable to demonstrate the whole search-ability. After several iterations, the walk boundary becomes smaller, which improves the local search-ability of the best location of the algorithm. Taking the convergence speed, algorithm stability and convergence precision as evaluation indicators, the improved Sparrow Algorithm (RWSSA) is verified by 4 unimodal functions and 5 multimodal classical test functions, and compared with the traditional Sparrow algorithm. The experimental results show that the capacity of the improved sparrow algorithm based on random walk is significantly improved. At the same time, RWSSA is put into practice the power prediction problem, which checkouts the feasibility of RWSSA in actual engineering problems.
Quantum regression in dephasing phenomena
Authors: Lonigro Davide , Chruściński Dariusz
Published: April 2022

We investigate the validity of quantum regression for a family of quantum Hamiltonians on a multipartite system leading to phase-damping reduced dynamics. After finding necessary and sufficient conditions for the CP-divisibility of the corresponding channel, we evaluate a hierarchy of equations equivalent to the validity of quantum regression under arbitrary interventions; in particular, we find necessary conditions for a nontrivial dephasing to be compatible with quantum regression. In this framework, we study a class of dephasing-type generalized spin–boson models, investigating the existence of qubit-environment coupling functions that ensure the exact validity of quantum regression.
Petroleum system modelling of Pelotas basin, offshore Brazil using 2D basin modelling approach
Authors: Hufaizal Muhammad Zulhakim , Abidin Nor Syazwani Zainal , Firdauz Mohd Syafiq
Published: April 2022

The ongoing exploration activities at the Pelotas basin of Brazil uncover some missing gaps in the existing wells for hydrocarbon accumulation prediction. Therefore, there is a need to further investigate the petroleum system of the basin, especially the organic facies, variations and distributions of the effectiveness of potential source rock. The adjacent basin, Santos basin is currently producing oil and gas fields will be used as the analogs to the Pelotas Basin. The aims of this research are to justify the presence of geological elements and processes of the petroleum system of the Pelotas Basin and to evaluate the potential of hydrocarbon prospectivity for exploration and exploitation of the basin. Two – dimensional basin modelling using TemisFlow will be used in this study. Hydrocarbon generation from the Turonian and Ypresian to Bartonian source rock started during Late Eocene. Visible Hydrocarbon migration can be seen from the Hydrocarbon saturation model. Hydrocarbon migration for Turonian source rock occurred during Early Miocene while for Ypresian to Bartonian, hydrocarbon migrate during Middle Miocene. Peak hydrocarbon expulsion reached during Middle Miocene for Turonian source rock and Ypresian to Bartonian source rock. Based on modelling result, hydrocarbon accumulation can be seen in Upper slope Early Miocene Sandstone, Early Miocene turbiditic sandstone and Early Oligocene turbiditic sandstone. Hydrocarbon composition in Early Miocene turbiditic sandstone and Upper Oligocene sandstone is mainly hydrocarbon liquid while for Early Miocene sandstone, the hydrocarbon composition is mix of hydrocarbon liquid and gas. Based on the prediction of source facies distribution, thermal maturity assessment, and migration and trapping mechanism, the oil and gas pool can be proposed for the future exploration and exploitation in the Pelotas Basin, offshore Brazil.
Real time imaging of the excitation volume of a multiphoton microscope
Authors: Kumar Maity Barun , Roy Debsankar Saha , Maiti Sudipta
Published: April 2022

Knowledge of the excitation profile in a confocal or multiphoton microscope can improve the image resolution, e.g. by using deconvolution, pixel reassignment or adaptive optics strategies. Here we demonstrate a method by which the scanning beam can be used to place a stationary, virtual ‘guide star’ at any chosen location in the sample, during imaging. This can then be used to directly image the excitation profile. The major advantage of our easy-to-install method, compared to competing methods, is that it can work for non-descanned multiphoton microscopy, the method of choice for deep tissue or ultraviolet imaging. Our experimental results reproduce diffraction theory based calculations in a minimally-scattering sample, and provide detailed information about the aberrated excitation profile in a highly scattering sample.
Effect of slitting of carbon fiber-reinforced plastic strip on flexural properties of reinforced concrete
Authors: Kwon Ji Eun , Chae See Hyeon , Kwon Sun Min , Jeong Ye Dam , Jeong Euigyung , Kim Jongwon
Published: April 2022

In this study, reinforced concrete was manufactured by attaching a carbon fiber reinforced plastic (CFRP) strips to the surface of the concrete. Strips with the same total area were slitted into one, two, three, four, and six pieces and attached to the upper, lower, and side parts of the concrete. The flexural strength and fracture toughness of the reinforced concrete were investigated. As the number of slits in the strip increased, for the upper reinforcement, the flexural strength gradually increased from 7.88 MPa to 11.21 MPa; for the lower reinforcement, the flexural strength increased significantly from 7.88 MPa to 26.48 MPa and then gradually increased to 33.90 MPa; and for the side reinforcement, the flexural strength increased from 7.12 MPa to 13.96 MPa and then gradually decreased. In the adhesive fracture toughness test, the fracture toughness energy significantly increased from 142.38 J m−2 to 516.63 J m−2 as the contact area between the adhesive and the strip increased. Therefore, in reinforcing concrete using a CFRP strip, it was confirmed that the reinforcement effect was enhanced when the strip was slit and then attached.
Branching of metaplectic representation of 𝑆𝑝(2,ℝ) under its principal 𝕊𝕃(2,ℝ)-subgroup
Authors: Zhang GenKai
Published: April 2022

We study the branching problem of the metaplectic representation ofSp(2,R)Sp(2, \mathbb R)under its principle subgroupSL(2,R)SL(2, \mathbb R). We find the complete decomposition.
On the socles of certain parabolically induced representations of 𝑝-adic classical groups
Authors: Atobe Hiraku
Published: April 2022

In this paper, we consider representations of

p
p

-adic classical groups parabolically induced from the products of shifted Speh representations and unitary representations of Arthur type of good parity. We describe how to compute the socles (the maximal semisimple subrepresentations) of these representations. As a consequence, we can determine whether these representations are reducible or not. In particular, our results produce many unitary representations, which appear in the complementary series.
Root and xylem anatomy varies with root length, root order, soil depth and environment in intermediate wheatgrass (Kernza®) and alfalfa
Authors: Clément Corentin , Schneider Hannah M , Dresbøll Dorte Bodin , Lynch Jonathan P , Thorup-Kristensen Kristian
Published: April 2022

Background and Aims

Deep roots (i.e. >1 m depth) are important for crops to access water when the topsoil is dry. Root anatomy and hydraulic conductance play important roles in the uptake of soil water, particularly water located deep in the soil. We investigated whether root and xylem anatomy vary as a function of root type, order and length, or with soil depth in roots of two deep-rooted perennial crops: intermediate wheatgrass [Thinopyrum intermedium (Kernza®)] and alfalfa (Medicago sativa). We linked the expression of these anatomical traits to the plants’ capacity to take up water from deep soil layers.

Methods

Using laser ablation tomography, we compared the roots of the two crops for cortical area, number and size of metaxylem vessels, and their estimated root axial hydraulic conductance (ERAHCe). The deepest roots investigated were located at soil depths of 2.25 and at 3.5 m in the field and in rhizoboxes, respectively. Anatomical differences were characterized along 1-m-long individual roots, among root types and orders, as well as between environmental conditions.

Key Results

For both crops, a decrease in the number and diameter, or both, of metaxylem vessels along individual root segments and with soil depth in the field resulted in a decrease in ERAHCe. Alfalfa, with a greater number of metaxylem vessels per root throughout the soil profile and, on average, a 4-fold greater ERAHCe, took up more water from the deep soil layers than intermediate wheatgrass. Root anatomical traits were significantly different across root types, classes and growth conditions.

Conclusions

Root anatomical traits are important tools for the selection of crops with enhanced exploitation of deep soil water. The development and breeding of perennial crops for improved subsoil exploitation will be aided by greater understanding of root phenotypes linked to deep root growth and activity.
Female blue tits sing frequently: a sex comparison of occurrence, context, and structure of song
Authors: Sierro Javier , de Kort Selvino R , Riebel Katharina , Hartley Ian R
Published: April 2022

In species with mutual mate choice, we should expect adaptive signaling in both sexes. However, the role of female sexual signals is generally understudied. A case in point is female birdsong that has received considerably less attention than male song. This holds even for well-studied species such as the blue tit (Cyanistes caeruleus), an important model in evolutionary ecology. Although there have been anecdotal reports of female song from three populations, there are no quantitative studies on female song in this species. Here, we report systematic sampling from a population of individually marked blue tits over 3 years, revealing that females sang frequently throughout the sampling period. Notably, daytime singing of females occurred in functionally similar contexts as in males (agonistic, solo song, and alarm contexts) but females had lower song output than males and were not observed singing dawn song, while males showed long singing displays at dawn before copulations take place. Female and male song overlapped substantially in acoustic structure (i.e., same song types or peak frequency) but females had smaller individual song-type repertoires, shorter trills, and lower vocal consistency. Differential selection pressures related to functional differences in male and female song might explain the observed variation in acoustic structure. With the first quantitative study of female song in such a well-studied species, we hope to stimulate further investigations into the functions of female singing, especially in the Northern temperate zones where female song may have been overlooked, not only in this but perhaps in other monomorphic species.
A heterogeneous network-based method with attentive meta-path extraction for predicting drug–target interactions
Authors: Wang Hongzhun , Huang Feng , Xiong Zhankun , Zhang Wen
Published: April 2022

Predicting drug–target interactions (DTIs) is crucial at many phases of drug discovery and repositioning. Many computational methods based on heterogeneous networks (HNs) have proved their potential to predict DTIs by capturing extensive biological knowledge and semantic information from meta-paths. However, existing methods manually customize meta-paths, which is overly dependent on some specific expertise. Such strategy heavily limits the scalability and flexibility of these models, and even affects their predictive performance. To alleviate this limitation, we propose a novel HN-based method with attentive meta-path extraction for DTI prediction, named HampDTI, which is capable of automatically extracting useful meta-paths through a learnable attention mechanism instead of pre-definition based on domain knowledge. Specifically, by scoring multi-hop connections across various relations in the HN with each relation assigned an attention weight, HampDTI constructs a new trainable graph structure, called meta-path graph. Such meta-path graph implicitly measures the importance of every possible meta-path between drugs and targets. To enable HampDTI to extract more diverse meta-paths, we adopt a multi-channel mechanism to generate multiple meta-path graphs. Then, a graph neural network is deployed on the generated meta-path graphs to yield the multi-channel embeddings of drugs and targets. Finally, HampDTI fuses all embeddings from different channels for predicting DTIs. The meta-path graphs are optimized along with the model training such that HampDTI can adaptively extract valuable meta-paths for DTI prediction. The experiments on benchmark datasets not only show the superiority of HampDTI in DTI prediction over several baseline methods, but also, more importantly, demonstrate the effectiveness of the model discovering important meta-paths.
Imputing dropouts for single-cell RNA sequencing based on multi-objective optimization
Authors: Jin Ke , Li Bo , Yan Hong , Zhang Xiao-Fei
Published: April 2022

Motivation

Single-cell RNA sequencing (scRNA-seq) technologies have been testified revolutionary for their promotion on the profiling of single-cell transcriptomes at single-cell resolution. Excess zeros due to various technical noises, called dropouts, will mislead downstream analyses. Therefore, it is crucial to have accurate imputation methods to address the dropout problem.

Results

In this article, we develop a new dropout imputation method for scRNA-seq data based on multi-objective optimization. Our method is different from existing ones, which assume that the underlying data has a preconceived structure and impute the dropouts according to the information learned from such structure. We assume that the data combines three types of latent structures, including the horizontal structure (genes are similar to each other), the vertical structure (cells are similar to each other) and the low-rank structure. The combination weights and latent structures are learned using multi-objective optimization. And, the weighted average of the observed data and the imputation results learned from the three types of structures are considered as the final result. Comprehensive downstream experiments show the superiority of our method in terms of recovery of true gene expression profiles, differential expression analysis, cell clustering and cell trajectory inference.

Availability and implementation

The R package is available at https://github.com/Zhangxf-ccnu/scMOO and https://zenodo.org/record/5785195. The codes to reproduce the downstream analyses in this article can be found at https://github.com/Zhangxf-ccnu/scMOO_experiments_codes and https://zenodo.org/record/5786211. The detailed list of data sets used in the present study is represented in Supplementary Table S1 in the Supplementary materials.

Supplementary information

Supplementary data are available at Bioinformatics online.
Comprehensive comparison of two types of algorithm for circRNA detection from short-read RNA-Seq
Authors: Liu Hongfei , Akhatayeva Zhanerke , Pan Chuanying , Liao Mingzhi , Lan Xianyong
Published: April 2022

Motivation

Circular RNA is generally formed by the ‘back-splicing’ process between the upstream splice acceptor and the downstream donor in/not in the regulation of the corresponding RNA-binding proteins or cis-elements. Therefore, more and more software packages have been developed and they are mostly based on the identification of the back-spliced junction reads. However, recent studies developed two software tools that can detect circRNA candidates by constructing k-mer table or/and de Bruijn graph rather than reads mapping.

Results

Here, we compared the precision, sensitivity and detection efficiency between software tools based on different algorithms. Eleven representative detection tools with two types of algorithm were selected for the overall pipeline analysis of RNA-seq datasets with/without RNase R treatment in two cell lines. Precision, sensitivity, AUC, F1 score and detection efficiency metrics were assessed to compare the prediction tools. Meanwhile, the sensitivity and distribution of highly expressed circRNAs before and after RNase R treatment were also revealed by their enrichment, unaffected and depleted candidate frequencies. Eventually, we found that compared to the k-mer based tools, CIRI2 and KNIFE based on reads mapping had relatively superior and more balanced detection performance regardless of the cell line or RNase R (-/+) datasets.

Availability and implementation

All predicted results and source codes can be retrieved from https://github.com/luffy563/circRNA_tools_comparison.

Supplementary information

Supplementary data are available at Bioinformatics online.
Dynamic zinc fluxes regulate meiotic progression in Caenorhabditis elegans
Authors: Mendoza Adelita D , Sue Aaron , Antipova Olga , Vogt Stefan , Woodruff Teresa K , Wignall Sarah M , O’Halloran Thomas V
Published: April 2022

Zinc influx and efflux events are essential for meiotic progression in oocytes of several mammalian and amphibian species, but it is less clear whether this evolutionary conservation of zinc signals is also important in late-stage germline development in invertebrates. Using quantitative, single cell elemental mapping methods, we find that Caenorhabditis elegans oocytes undergo significant stage-dependent fluctuations in total zinc content, rising by over sevenfold from Prophase I through the beginning of mitotic divisions in the embryo. Live imaging of the rapid cell cycle progression in C. elegans enables us to follow changes in labile zinc pools across meiosis and mitosis in single embryo. We find a dynamic increase in labile zinc prior to fertilization that then decreases from Anaphase II through pronuclear fusion and relocalizes to the eggshell. Disruption of these zinc fluxes blocks extrusion of the second polar body, leading to a range of mitotic defects. We conclude that spatial temporal zinc fluxes are necessary for meiotic progression in C. elegans and are a conserved feature of germ cell development in a broad cross section of metazoa.
Assessing executive functions in post-stroke aphasia—utility of verbally based tests
Authors: Schumacher Rahel , Halai Ajay D. , Lambon Ralph Matthew A.
Published: April 2022

It is increasingly acknowledged that, often, patients with post-stroke aphasia not only have language impairments but also deficits in other cognitive domains (e.g. executive functions) that influence recovery and response to therapy. Many assessments of executive functions are verbally based and therefore usually not administered in this patient group. However, the performance of patients with aphasia in such tests might provide valuable insights both from a theoretical and clinical perspective. We aimed to elucidate (i) if verbal executive tests measure anything beyond the language impairment in patients with chronic post-stroke aphasia, (ii) how performance in such tests relates to performance in language tests and nonverbal cognitive functions, and (iii) the neural correlates associated with performance in verbal executive tests. In this observational study, three commonly used verbal executive tests were administered to a sample of patients with varying aphasia severity. Their performance in these tests was explored by means of principal component analyses, and the relationships with a broad range of background tests regarding their language and nonverbal cognitive functions were elucidated with correlation analyses. Furthermore, lesion analyses were performed to explore brain–behaviour relationships. In a sample of 32 participants, we found that: (i) a substantial number of patients with aphasia were able to perform the verbal executive tests; (ii) variance in performance was not explained by the severity of an individual’s overall language impairment alone but was related to two independent behavioural principal components per test; (iii) not all aspects of performance were related to the patient’s language abilities; and (iv) all components were associated with separate neural correlates, some overlapping partly in frontal and parietal regions. Our findings extend our clinical and theoretical understanding of dysfunctions beyond language in patients with aphasia.
24: IDEAL IMPLEMENTATION OF THE MINIMALLY INVASIVE CERVICAL ESOPHAGECTOMY (MICE), A JAPANESE-DUTCH COLLABORATION
Authors: Klarenbeek B , Shiozaki A , Fujiwara H , Rosman C
Published: April 2022

Background and aim

MICE is an innovative Japanese surgical technique, combining a laparoscopic transhiatal and a single port cervical mediastinal dissection in patients operated for esophageal cancer. This complex surgical techniques aims to reduce pulmonary morbidity without compromising oncological radicality by avoiding thoracic access, prevailing pleural integrity and facilitating cervical or abdominal instead of pleural drainage of mediastinal infections in case of anastomotic leakage. Potential drawbacks are an increased risk of recurrent laryngeal nerve injury and learning associated morbidity during the implementation phase. Up to date this technique is not routinely performed in European esophageal cancer patients.

Methods

In order to explore the feasibility and safe implementation of the MICE procedure in Dutch esophageal cancer patients, the evidence based IDEAL-framework will be followed. This framework describes 6 stages of evolution for new surgical therapeutic interventions: Pre-clinical, First in human, Development, Exploration, Assessment and Long-term Study. Outcomes of the first two phases will be described.

Results

The Pre-clinical phase consisted of on-site visits to a Japanese expert center, protocol development, prospective risk assessment, instrument collection and extensive cadaveric training on six fresh frozen human bodies. A ‘virtual supervision platform’ has been developed to proceed with the implementation process despite the COVID pandemic. After thorough evaluation with Dutch upper GI surgical experts and esophageal cancer patients, we have proceeded to the ‘First in Human’ phase.

Conclusion

The IDEAL framework was used as an evidence based tool for safe implementation of the MICE procedure. We will present the results of the ‘pre-clinical’ and ‘first in human’ stage as well as the surgical technique of the MICE procedure.
36: ANASTOMOTIC STRICTURE AFTER IVOR LEWIS OESOPHAGECTOMY—AN EVALUATION OF INCIDENCE, RISK FACTORS AND TREATMENT
Authors: Koshy R , Brown J , Chmelo J , Watkinson T , Phillips A W
Published: April 2022

Background and aim

Anastomotic stricture is a recognised complication after oesophagectomy. It can impact on patient quality of life with some patients requiring multiple dilatations. The aim of this study was to evaluate the frequency of strictures, contributing factors and the long-term outcomes of management in patients undergoing oesophagectomy with thoracic anastomosis using a standardised circular stapled technique.

Methods

All patients who underwent a two-stage transthoracic oesophagectomy with curative intent between January 2010 and December 2019 at the Northern Oesophago-Gastric Unit (NOGU) in Newcastle upon Tyne, UK were included. All patients who underwent a stapled (circular) intrathoracic anastomosis using a gastric conduit were included. Stricture incidence, number of dilatations to treat strictures and refractory stricture rate were recorded.

Results

Overall 705 patients were included with 192 (27.2%) developing strictures. Refractory strictures occurred in 38 patients (5.4%). One, two and three dilatations were needed for resolution of symptoms in 46 (37.4%), 23 (18.7%) and 20 (16.3%) patients respectively. Multivariable analysis identified the occurrence of an anastomotic leak (OR 1.906, 95% CI 1.088–3.341, P = 0.024) and circular stapler size less than 28 mm (OR 1.462, 95% CI 1.033–2.070, P = 0.032) as independent predictors of stricture occurrence. Patients with anastomotic leaks were more likely to develop refractory strictures (13.1% vs. 4.7%, OR 3.089, 95% CI 1.349–7.077, P = 0.008).

Conclusion

This study highlighted that 27.2% of patients having a circular stapled anastomosis required dilatation after surgery. However, most strictures were successfully treated after two dilatations, but 5% of patients had longer-term problems with refractory strictures.
53: SIGNIFICANCE OF NEOADJUVANT DOWNSTAGING IN ADENOCARCINOMA OF THE STOMACH
Authors: Prasad P , Sivaharan A , Navidi M , Phillips A
Published: April 2022

Background and aim

Neoadjuvant chemotherapy is established in the treatment of gastric adenocarcinoma. Histopathological regression as a result of neoadjuvant treatment may have important prognostic implications. There is little data comparing the prognosis of clinical versus pathological stage in patients receiving neoadjuvant treatment. Equally, comparison of outcomes of patients with comparable pathological stage that have received neoadjuvant treatment with those having surgery as their initial treatment is not known. The aim of this study is to determine the impact of neoadjuvant chemotherapy upon the prognosis of patients treated for gastric adenocarcinoma.

Methods

Consecutive patients with gastric cancer from a single, centre between 2007 and 2017 were evaluated. All patients with gastric adenocarcinoma were treated with either a subtotal or total gastrectomy and D2 lymphadenectomy. The impact of downstaging on outcomes and a stage-by-stage comparison of pTNM with ypTNM was performed.

Results

654 patients underwent gastrectomy, 345 patients received neoadjuvant chemotherapy. Patients with downstaged disease had improved overall survival than patients with tumours that did not respond to neoadjuvant chemotherapy (P < 0.001). Downstaging by more than 3 stages was the strongest independent predictor of overall survival when compared with patients who did not respond to neoadjuvant treatment (median survival: 122 vs 66 months, P < 0.001). Survival was significantly improved for patients with advanced overall staging when a stage-wise comparison was performed between patients in like-for-like ypTNM and pTNM groups (ypT 3/4 N2/3 vs pT3/4 N2/3 median survival: 33 vs 16 months, P = 0.001).

Conclusion

Pathological staging following neoadjuvant chemotherapy is better for survival prognostication compared to clinical stage. Downstaging is associated with improved prognosis. There is a significant improvement in survival when comparing pathological stage post neoadjuvant treatment compared to those with a similar stage who had surgical treatment initially.
145: THE USE OF MACHINE LEARNING FOR REAL-TIME DETECTION OF OESOPHAGEAL AND GASTRIC CANCER BASED ON DIFFUSE REFLECTANCE SPECTROSCOPY: A VALIDATION STUDY
Authors: Gkouzionis I , Nazarian S , Kawka M , Peters C , Elson D S
Published: April 2022

Background and aim

The lack of a fast and accurate intraoperative tumour margin assessment tool contributes to high positive circumferential resection margin rates for oesophageal and gastric cancers, which is associated with local recurrence and poor long-term survival. Diffuse reflectance spectroscopy (DRS) can provide non-invasive, accurate, and real-time tissue classification based on quantification of light reflectance in tissue, providing a unique optical fingerprint of the tissue. This study aimed to validate the use of DRS for discrimination between normal and cancerous tissues based on ex-vivo gastric and oesophageal cancer resection specimens.

Methods

Consecutive patients undergoing resections for gastric and oesophageal carcinomas at a tertiary referral centre in London between July 2020 and June 2021 were included. Reflectance data in the 468-720 nm spectral range were recorded on ex-vivo specimens within 15 minutes of surgical specimen excision. Based on video recordings of the data acquisition procedure and probe tip tracking, sampling sites were correlated with histological reports manually labeled as either normal or cancer (Figure 1). Following spectral data normalisation and feature selection, four supervised machine learning approaches were tested for classification using 5-fold cross-validation. Overall classification accuracy and Area Under the Curve (AUC) across machine learning approaches were compared.

Results

A total of 32 patients (median age 68, 75% male) were included. 11,862 mean spectra (2990 spectra for normal oesophagus, 4628 for normal stomach, 2305 for gastric cancer, and 1939 for oesophageal cancer) were collected. For oesophageal cancer, classification accuracy was 96.22 ± 0.50 and AUC was 99.24 ± 0.19, while for gastric cancer, the accuracy was 93.86 ± 0.66, and AUC 98.50 ± 0.28 for gastric cancer. For both malignancy types, Extreme Gradient Boosting was the best performing classifier. The differences in spectral data between patients receiving neoadjuvant treatment and treatment naïve were non-significant.

Conclusion

Machine learning can be used to accurately differentiate between normal and cancerous oesophageal and gastric tissues in an ex-vivo setting, based on DRS data. Features used for class discrimination should be investigated to find possible physiological correlates of spectral data differences. Future intraoperative validation is required to assess the utility of this technology for real-time tumour margin mapping and its effect on long-term outcomes.
189: THE EFFECT OF COVID -19 ON THE NEW DIAGNOSIS OF ESOPHAGOGASTRIC CANCER IN THE UK: A SINGLE-CENTRE EXPERIENCE
Authors: Mcquillan P , Ahmed S , Hayes N , Wahed S , Navidi M , Immanual A , Phillips A
Published: April 2022

Background and aim

Covid-19 has had a devastating global impact and resulted in over 4.4 million directly attributed deaths. The UK entered lockdown in March 2020, redistributing its medical workforce and resources. Early estimations suggested at least 4700 extra cancer deaths at 5 years if there was a 3-month delay to surgery. Delays to diagnosis and treatment for esophagogastric (EG) cancers can be particularly detrimental to survival. The aim of this study is to assess the impact of Covid-19 on new cancer referrals to a centralised UK EG cancer centre, including presentation, decision making and treatment.

Methods

Patients with EG cancer referred to a tertiary, high-volume centre between March 2019 and March 2021 were reviewed. Patients were stratified into Pre-covid (March 2019–March 2020) and Covid (March 2020–2021) cohorts. Number of new referrals, clinical stage, treatment decision, and time to treatment were compared for gastric adenocarcinoma (GA), esophagogastric-junction adenocarcinoma (EGJA), esophageal adenocarcinoma (EA) and esophageal SCC (ESCC).

Results

There was an 11% reduction in new cancer referrals (485 vs 431). GA, EGJA and EA did not have significant change in treatment intent, although there was a significant increase in the decision for definitive non-surgical treatment of EA (P = 0.046). GA and EA patients had a small, but significant increase in average clinical stage at presentation (P < 0.05). There was no increase in time to treatment for GA, EGJA and EA. A significantly higher proportion of ESCC patients were given curative intent treatment in the Covid-19 cohort (P = 0.0006) however, this was accompanied with an increased time to treatment (35.8 days vs 27.9 days P = 0.0198).

Conclusion

This high-volume centre has seen a reduction in new cancer referrals since the first UK lockdown. This was associated with a small, but significant, increase in clinical stage of GA and EA at presentation. This may represent an early indication of excess esophagogastric cancer deaths due to the impact of Covid-19. This data also confirms initial results showing that oncological decisions were not compromised, although Covid-19 remains a dynamic challenge.
Satisfaction With Life and Risk of Dementia: Findings From the Korean Longitudinal Study of Aging
Authors: Zhu Xianghe , Luchetti Martina , Aschwanden Damaris , Sesker Amanda A , Stephan Yannick , Sutin Angelina R , Terracciano Antonio
Published: April 2022

Objectives

Life satisfaction is increasingly viewed as an asset associated with better general health, but its association with cognitive health and risk of dementia is less examined. We tested the hypothesis that higher life satisfaction would be associated with lower risk of dementia.

Methods

Participants were a nationally representative sample of adults (n = 8,021; age range: 45–93 years) from the Korean Longitudinal Study of Aging assessed every 2 years for up to 12 years. Multilevel modeling analysis examined whether life satisfaction is associated with cognitive functioning and decline. The primary analysis used Cox regression to examine the association between baseline life satisfaction and risk of incident dementia.

Results

Between-person differences and within-person changes in life satisfaction were associated with cognitive functioning, but life satisfaction was unrelated to the rate of cognitive decline. Higher life satisfaction was also associated with lower risk of dementia, even after accounting for demographic factors, depressive symptoms, cardiovascular and functional risk factors, health behaviors, and social contact.

Discussion

Satisfaction with life may function as a positive psychological resource for maintaining cognitive functioning and protecting against the risk of dementia.
Geodesics in the Space of m-Subharmonic Functions With Bounded Energy
Authors: Åhag Per , Czyż Rafał
Published: April 2022

We raise our cups to Urban Cegrell, gone but not forgotten, gone but ever here. Until we meet again in Valhalla!

With inspiration from the Kähler geometry, we introduce a metric structure on the energy class, $\mathcal {E}_{1,m}$, of $m$-subharmonic functions with bounded energy and show that it is complete. After studying how the metric convergence relates to the accepted convergences in this Caffarelli–Nirenberg–Spruck model, we end by constructing geodesics in a subspace of our complete metric space.
A small molecule targeting hepatitis B surface antigen inhibits clinically relevant drug-resistant hepatitis B virus
Authors: Kiruthika S , Bhat Ruchika , Jayaram B , Vivekanandan Perumal
Published: April 2022

Background

Currently approved oral antivirals for chronic HBV infection target the reverse transcriptase (RT) domain of the HBV polymerase. Emergence of drug resistance has been reported in a small proportion of chronic HBV patients on prolonged treatment with antivirals. We recently reported ZINC20451377, a small molecule targeting hepatitis B surface antigen (HBsAg) that effectively inhibits both WT HBV and tenofovir-resistant HBV. Due to the partial overlap between the RT domain and HBsAg, drug-resistant mutants are associated with corresponding mutations in HBsAg.

Objectives

To evaluate the efficacy of ZINC20451377 against nine clinically relevant drug-resistant HBV mutants that lead to simultaneous mutations in the overlapping HBsAg gene.

Methods

Huh7 cells were transfected with 1.2× HBV replicons corresponding to WT HBV or drug-resistant HBV mutants and treated with different concentrations of ZINC20451377. We assessed the IC50 values of ZINC20451377 for HBsAg levels in the culture supernatants using ELISAs. HBV secretion was measured by immunocapture of secreted virions followed by real-time PCR quantitation of virion-associated DNA.

Results

ZINC20451377 led to a dose-dependent inhibition of secreted HBsAg encoded by WT HBV and all nine drug-resistant mutants tested and the IC50 values were in the low micromolar range. ZINC20451377 inhibited HBV secretion from drug-resistant mutants except for mutants harbouring the rtL180M + rtM204V (MV) mutation.

Conclusions

The small molecule ZINC20451377 inhibits HBsAg and virion secretion in some of the clinically relevant drug-resistant HBV mutants. ZINC20451377 has a modest overall effect, and it was not effective against the MV mutants (lamivudine- and entecavir-resistant mutants).