bluuebunny/crossref_metadata_2025 huggingface dataset:
Space charged based Residual Ion beam recovery for the Neutral beam injection
Authors: Variale V. , Cavenago M. , Valentino V.
Published: April 2022

Energy recovery of residual ions may be needed to increase the energy efficiency of Neutral Beam (NB) injectors for fusion plants as DEMO while a deflection-based system has been proposed until now to dump residual ions. As an alternative, a compact beam energy recovery system, based on space charge effects due to the residual ion deceleration into 2 Farady Cups (FC) with holes for D0 passage, can replace the Electrostatic Residual Ion Dump (ERID) designed for ITER to stop the residual D- and D+ before the NB injection in the tokamak plasma. All parameter tunings and preliminary simulations are here described, also providing the suppression of back streaming to the ion source. Ion energy spread and rectangular geometry are considered. Collection of ions at low energy (a few percent of the full neutral beam energy Eki) instead of Eki as in ERID gives advantages that will be mentioned.
Reverse trajectory analysis of the hydrogen negative ion beam in a prototype accelerator for ITER
Authors: Kisaki M , Kojima A , Saquilayan G Q , Hiratsuka J , Ichikawa M , Shimabukuro Y , Murayama M , Watanabe K , Tobari H , Kashiwagi M
Published: April 2022

Reverse calculation of negative ion trajectory based on the measured beam emittance has been performed for the first time in multi-stage accelerator in order to reconstruct negative ion profile near meniscus, which has been a long-term issue for negative ion sources. According to reverse calculation, negative ions are mainly extracted from the periphery of extraction area, and the particles extracted from the aperture edge is lost on acceleration grids. By taking into account the lost component with reconstructed negative ion profile, the negative ion trajectory became consistent with observed beam traces on the acceleration grids. This result can be applied directly to the design of ITER accelerator as well as the other Cs-seeded negative ion sources.
A cold electron-impact ion source driven by a photo-cathode – New opportunities for the delivery of radioactive molecular beams?
Authors: Ballof Jochen , Au Mia , Barbero Ermanno , Chrysalidis Katerina , Düllmann Christoph E , Fedosseev Valentin , Granados Eduardo , Heinke Reinhard , Marsh Bruce A , Owen Michael , Rothe Sebastian , Stora Thierry , Yakushev Alexander
Published: April 2022

The thick-target ISOL (Isotope mass Separation OnLine) method provides beams of more than 1000 radionuclides of 74 elements. The method is well established for elements with sufficiently high volatility at ca. 2000 °C. To extract non-volatile elements the formation of a volatile molecule is required. While successful in some cases (e.g. carbon or boron), most of these elements are not yet available as ISOL beam. A variety of volatile carrier molecules has been proposed for all elements produced in the target material, but their probability of survival during the extraction and ionization process is often limited by the high temperatures required for isotope diffusion in the thick targets and for ion source operation. While cold target concepts have already been proposed, the normal mode of operation of the typically used Versatile Arc Discharge Ion Source (VADIS) with a hot cathode is not well suited. Here, we report about first measurements with an electron-impact ion source operated at ambient temperature using electrons that were liberated via the photo-electric effect from a copper cathode.
Investigation of Ho ion production with a laser ablation ion source
Authors: Bhandari R. , Horana Gamage M. , Gamage N. D. , Redshaw M.
Published: April 2022

At Central Michigan University (CMU), we are developing the CMU High Precision Penning Trap (CHIP-TRAP) with the aim of performing high-precision mass measurements on stable and long-lived radioactive isotopes. A major goal of CHIP-TRAP is to measure the 163Ho EC Q value to ∼1 eV precision to aid direct neutrino mass determination experiments with 163Ho. CHIP-TRAP utilizes a laser ablation source (LAS) and a Penning ion trap source to produce ions from solid and gaseous samples, respectively. Ions from these sources are identified by measuring their times-of-flight from the source to their detection on a micro channel plate detector (MCP). With the goal of producing 163Ho+ ions from a solution of 163Ho dissolved in nitric acid and dried out on a backing target to be inserted into the LAS, we investigated the production of naturally occurring, stable 165 Ho+ following this method. We aimed to determine the minimum number of Ho atoms required on the target to produce a detectable number of Ho+ ions, and to investigate different backing materials to determine if a particular material minimized contaminant ions from the backing material and maximized the number of Ho+ ions compared to, for example, HoO+ ions.
Resolution improvement of electrostatic ion analyzer using additional slit for laser ion source
Authors: Takahashi K , Matsumoto Y , Sasaki T , Kikuchi T
Published: April 2022

A laser ion source provides an ion beam extracted from a drifting plasma produced by irradiating a high power laser on a solid target. Ion species contained in the plasma can be analyzed with an electrostatic ion analyzer (EIA). However, to distinguish ion species with close mass-to-charge ratio, high resolution is required due to the high drifting velocity. In order to improve the resolution of the EIA, we investigated the cause of spectral width broadening by simulation. The simulation result showed that the spectral broadening occurs because ions go through the paths in different angle rather than it is caused by difference of ion velocity in the conventional analyzer using two slits. To limit the angular distribution of the paths, we suggested to use an additional slit for the EIA. To demonstrate the effect of the additional slit on the spectral width broadening for the EIA, we investigated the variation in the spectral signals obtained with the suggested EIA. The experimental result indicated that the resolution of EIA can be improved by adding a slit to limit the trajectories in angular distribution of ion paths.
Design of the proton injector for compact neutron source DARIA
Authors: Skalyga V.A. , Izotov I.V. , Vybin S.S. , Kulevoy T.V. , Kropachev G.N. , Sitnikov A.L. , Grigoriev S.V.
Published: April 2022

Project of the proton accelerator-driven compact neutron source DARIA (Dedicated for Academic Research and Industrial Application) is developed in order to replace small and middle flux neutron sources based on the nuclear reactors. DARIA has a uniquely high ratio of efficiency to cost due to deep optimization of each key element of the system (proton injector and accelerator, target, neutron moderator and neutron instruments. A unique ECR ion source, developed at the IAP RAS, would be used as a proton beam injector. In such device the plasma is heated by the powerful 28 GHz gyrotron radiation, providing a record level of volumetric energy input for such systems over 100 W/cm^3. The high plasma density and the optimal electron temperature provide proton beams formation with a current of up to several hundred mA and an emittance that meets the requirements of modern accelerators. The paper discusses the advantages of using such an ion source, its scheme and design performance.
Optimized deceleration characteristics of multicharged ion beams from electron cyclotron resonance ion source
Authors: Sato K , Harisaki S , Kubo W , Owada I , Tsuda K , Anan M , Maenaka T , Kato Y
Published: April 2022

At present it is necessary the satellite lifetime 10-15 years for operating in space. Xenon is used as fuel for ion engines of satellites. There are problems of accumulated damages at irradiation and sputtering by low energy Xe ion from the engine. It is required to construct database of sputtering yield of ion beams in the low energy region from a hundred eV to 1keV. We are trying to investigate experimentally sputtering yield on satellite component by irradiating the low energy Xe
q+
ion beams. We use the electron cyclotron resonance ion source (ECRIS) in the irradiation experiments. We decelerate the beam energy to several hundred eV after extraction at high voltage 10kV. It is found we cannot neglect the contribution of the space potential of the plasma in the ECRIS of several tens eV. We measured the plasma parameters and ion beam deceleration characteristics in operating conditions on ECRIS. As the results, it was found in operating ECRIS condition of low charge state ion being dominant that the space potential of the ECRIS has an effect of 10∼20% at the beam energy at about 100eV in conducting irradiation experiments on satellite component materials.
Performance of a reactive magnetron sputtering ion source using water vapor plasma
Authors: Catapang Allen Vincent , James Edward Hernandez II , Vasquez Magdaleno R. , Wada Motoi
Published: April 2022

One of the methods used to produce ions of metals and metal oxides is through extracting them from a magnetron sputter-type ion source. Metal nanoparticles, such as zinc oxide (ZnO), can be deposited using this method. However, low-energy conditions are required to prevent damage to the substrate. The extraction of ions from a differentially pumped, reactive magnetron sputtering source with a pulsed, conduit-type extraction electrode is investigated, with Zn as the metal target and argon and water vapor as discharge support and reactive gases, respectively. The use of water vapor has been shown to improve the properties of ZnO, through hydrogen doping. Using a quadrupole mass analyzer, the species produced from the ion source were detected and identified. Ar, H2O, H3O, and Zn ions were extracted using the pulsed extraction electrode, and the intensity of the extracted ions were found to be frequency dependent. Extraction of ions were observed starting from-40 V extraction potential using a Faraday cup, and the ion beam current appeared to increase in proportion to the extraction voltage. A mechanism for realizing ion extraction using an alternating extraction potential is proposed.
Parallel Disassembly Sequence Planning of Retired Lithium-ion-battery Pack based on Heuristic Algorithm
Authors: Kong Shuai , Zhang Yuanliang , Liu Weiwei
Published: April 2022

With the explosive growth of the electric vehicle market, the recycling work of retired lithium-ion-battery packs, modules and cells is facing great challenges. Dismantling process is the primary step of the electronic waste recycling. In order to achieve rapid, efficient and safe disassembly of battery packs, and improve resource utilization efficiency, reduce environmental pollution, it is necessary to set battery pack disassembly production line. Based on the above targets, four optimization objectives are set, which are idle time, safety factor, disassembly cost and number of workstations. The solving part applies five heuristic algorithms, which can not only expand the solution range, but also discuss the performance of these algorithms. By comparing the value of objective functions, fitness and other indicators, NSGA-II is considered to have better convergence, and the optimal disassembly scheme is given.
A Photovoltaic Charger Suitable for Brain Computer Interface Equipment
Authors: Gu Yifeng , Li Hao , Zhao Jiale , Ma Xiaolin
Published: April 2022

Nowadays, traditional energy is drying up and environmental pollution is increasing. In order to implement the development requirements of energy saving and environmental protection, an efficient and portable photovoltaic charger is designed in this paper with brain computer interface devices as the research object On the hardware side the device is designed with a Boost circuit as the main circuit and on the software side a maximum power point tracking technique with conductance increment method as the control algorithm. Based on the final physical test results, it has been shown that the charger meets the requirements.
Design and Application of Intelligent Unmanned Spot Inspection System in Thermal Power Plant
Authors: Yang Yulei , Chen Kaifeng , Wu Zhanyuan , Xu Haocheng , Liu Jinliang , Li Lun
Published: April 2022

Thermal power plant is a typical equipment-intensive enterprise, and regular inspection and spot inspection of production equipment is the most important measure to find equipment defects in time and ensure safe production of enterprises. In many years of practical application, the traditional inspection method, which relies mainly on visual inspection by spot inspectors, has been widely used. There are many shortcomings, such as missing detection, low efficiency, insufficient depth of data mining and high security risk. Based on the equipment management mode of spot inspection and regular maintenance in power plants, this paper proposes an unmanned intelligent spot inspection system for power plants, which combines intelligent sensors with diagnostic algorithms, by sorting out the work content of traditional manual spot inspection. The intelligent and unmanned management of spot inspection and regular repair in thermal power plants is realized, which has certain reference significance for improving the operation reliability of power plants and reducing the safety risk of spot inspection personnel.
Study on adsorption of levofloxacin on Okra rod activated carbon
Authors: Jin Haitong , Wang Liye , Gang Siqi , Lv Shuang , Liang Hongyu , Lu Guang
Published: April 2022

Okra rod activated carbon was used as an adsorbent to remove levofloxacin in water. And effect of pH, adsorption time and adsorbent dosage on the adsorption effect were studied. The results were shown that the optimal pH was 5 and 10. The adsorption desorption equilibrium over Okra rod activated carbon was reached, when the adsorption time increased to 60min and 90min as pH = 5 and pH=10, respectively. Compared with the original Okra rod, the adsorption capacity of the Okra rod activated carbon was greatly improved. And the optimal dosage of Okra rod activated carbon was 50mg. The suitability of sorption isotherm model for the sorption of levofloxacin over Okra rod activated carbon is L Freundlich with high R2.
Three-phase unbalanced voltage sag detection method based on morphological filtering
Authors: Guo Zhicheng
Published: April 2022

In dynamic voltage restorer (DVR), accurate and fast voltage sag detection method is the key. However, in the case of three-phase imbalance, the traditional voltage sag detection method still has shortcomings in real-time and accuracy. Therefore, a voltage sag detection method based on morphological filter is proposed. That is, based on the commonly used dq transformation method, the morphological filter is used to replace the Butterworth low-pass filter to suppress the second harmonic generated by the negative sequence component after dq transformation in the case of three-phase imbalance, reduce the system delay and improve the real-time and accuracy of the detection method. The morphological filter is designed, and the appropriate structural elements and morphological transformation algorithm are selected. The results show that the morphological filter has good filtering effect and small delay, and can better meet the detection requirements of DVR.
Design of Smart Home System Based on Nb-Iot
Authors: Han Chenye , Zhang Weiwei , Li Meng , Tian Yunxia
Published: April 2022

In order to solve the problems of high power consumption, complex access network and unstable connection in smart home, a smart home system based on narrowband Internet of things NB-IoT technology is studied. The system uses STM32L431 chip of ST company’s ultra-low power series as the microcontroller, BC95-B5 as the communication module, collects data through a variety of sensors, uploads the collected data information to the remote Huawei cloud server using COAP protocol, and the mobile app accesses the cloud platform and obtains data for display and control. Through the test, the system realizes the function of intelligent control and can greatly improve the intelligent level of home.
Degradation and health prediction of filter components of screw compressor
Authors: Li Fengyu , Liu Xiaoming , Liu Zhilong , Yu Yang
Published: April 2022

In the oil screw compressor unit, the filtration device of gas and oil will have an impact on the overall operation of the unit. This paper studies the degradation of the filtration components in the long-term experiment. The experimental results show that with the increase of operation time, the fuel injection device, air cooling device, oil cooling device and oil filter device appear obvious degradation. The fuel injection temperature decreases, the inlet and outlet temperature difference of air cooling and oil cooling device increases, and the inlet and outlet pressure difference of oil filter device increases. Through the calculation of Mahalanobis distance, it is found that the degradation of each device corresponds to the degradation of the whole unit, and the degradation of oil filter device occurs first, followed by air cooling and oil cooling device, and affects the main engine from the fuel injection device. Through the calculation and comparison of artificial neural network, the optimal number of hidden layer neurons corresponding to the prediction model is determined.
Automatic control design of light wall panel production line
Authors: Chen Jiwen , Meng Decai , Zhang Rui , Yang Hongjuan , Bei Taixue , Ji Shuai
Published: April 2022

In order to promote the intelligent and standardized production of green light-weight wall materials in prefabricated buildings, an electrical automation control system for light-weight wall panels based on PLC technology was proposed. The process flow of the wall panel production line is analyzed, and the hardware system of the control system is determined through the selection of hardware such as motors and cylinders. The batching system, extrusion molding system, cutting system, palletizing system, transfer and maintenance system, etc. can be programmed through PLC technology. and automated production of wall panels can be accomplished by utilizing sensors and limit switches.
Direct Torque Control of Asynchronous Generator Based on Active Disturbance Rejection Controller
Authors: Li Wenhao , Liang Haiping
Published: April 2022

Induction generator is simple in structure and low in cost. Direct torque control is used to achieve the rapid response of induction motor electromagnetic torque and has good dynamic effect and simple control structure, but it is difficult to achieve satisfactory results considering that the method is easily affected by uncertain factors such as stator resistance parameter variation, load mutation and speed disturbance. Therefore an active disturbance rejection controller is applied to control DC voltage to reduce negative impact of unknown disturbances in the model that was built by observing and compensating the total disturbances. The results show that the scheme has the features of rapid response, robustness, and outputs dc voltage stably.
Intelligent Temperature Control System of Greenhouse Based on STM32 Single Chip Microcomputer
Authors: Wei Xinhua
Published: April 2022

With the development of automatic control technology and the popularization of agricultural science and technology, people are more and more aware of the intelligence convenience. In this study, a set of intelligent greenhouse temperature control system is established based on single chip microcomputer STM32F103. PID algorithm is used to realize stepless adjustment of greenhouse temperature, and complete the temperature automatic monitoring and control. It solves the greenhouse problems of low automation degree, large amount of manual work and low control accuracy of crop growth environment. The system simulation and practice show that it can improve the temperature and humidity control accuracy of greenhouse by 10.8%, and reduce the amount of manual work, and provide a good natural environment for plant growth and development, and have high economic benefits.
Simulation and analysis of sag control of microgrid inverters
Authors: Guo Jiahao , Lun Jingyi , Yang Xiong
Published: April 2022

A good inverter control strategy helps to maintain the stable operation of microgrid, and sag control is a common control strategy. Since the traditional sag control has the problem of difficult to stabilize the voltage frequency when switching the load. In this paper, we propose an improved sag control by introducing fuzzy control and linear self-rejecting control techniques into the voltage and current dual-loop structure of sag control, respectively, and build the simulation in Matlab/Simulink. The simulation comparison results show that the linear self-rejecting control has the best performance in stabilizing the voltage and frequency and tracking the reference value during load switching of the microgrid with better robustness than the PI control in the traditional sag control and the improved fuzzy control.
The Research on Condition Monitoring and Fault Diagnosis Method of Wind Power Spindle Bearing
Authors: Ye Lin , Lin Zhuang , Xuan Liang , Hong Wenxiong , Sun Tongjin , Yang Peijie , Yan Bowei
Published: April 2022

With the continuous and substantial increase in the demand for wind power generation in China, the development of wind power generation units tends to be large-scale, intelligent and efficient. Besides, the working environment of spindle bearings is relatively bad and the failure rate is relatively high. Therefore, it is necessary to conduct state monitoring and fault diagnosis for wind power generation units. This paper first introduces the bearing system of wind turbine, then expounds the common faults of wind turbine spindle bearing, and carries out relevant research. According to the fault types, this paper investigates and combs the condition monitoring and fault diagnosis methods of spindle bearing. Finally, the author proposing a new condition monitoring method, which solves the vacancy of condition monitoring method based on strain.
Effect of extrusion speed on microstructure and mechanical properties of Mg-Al-Ca-Sn alloy
Authors: Zhang Maochao , Yang Chao , Li Zhenshuai , Bao Shuai , Ye Peiran , Chen Yungui
Published: April 2022

Low-temperature and high-speed extrusion of wrought magnesium alloy is an urgent problem. Mg-2.5Al-2Ca-1Sn alloys were extruded at 260 °C with different ram speeds (2.0, 4.0 and 6.0 mm s)−1. The effects of extrusion speed on the microstructure and mechanical properties of the alloys were systematically investigated. It’s worth noting that all the three extruded alloys were fully dynamic recrystallized (DRXed). With the increase of extrusion speed from 2 mm s−1 to 6 mm s−1, the DRXed grain size are increased from 1.25 μm to 1.94 μm, average second phase particles are augmented from 0.79 μm to 0.89 μm and the volume fraction of second phase increases from 6.4% to 18.6%. All the three extruded samples show excellent comprehensive mechanical properties because of fine grain size, fully recrystallization and homogeneously dispersed second phase particles. The tensile yield strength (TYS) and ultimate tensile strength (UTS) decreased from 285 MPa, 304 MPa to 217 MPa, 264 MPa while the elongation increased from 11.4% to 20% when the ram speed rose from 2.0 mm s−1 to 6.0 mm s−1.
Characterizing the Spatiotemporal Heterogeneity of the COVID-19 Vaccination Landscape
Authors: Tiu Andrew , Susswein Zachary , Merritt Alexes , Bansal Shweta
Published: April 2022

As variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have emerged throughout 2021–2022, the need to maximize vaccination coverage across the United States to minimize severe outcomes of coronavirus disease 2019 (COVID-19) has been critical. Maximizing vaccination requires that we track vaccination patterns to measure the progress of the vaccination campaign and target locations that may be undervaccinated. To improve efforts to track and characterize COVID-19 vaccination progress in the United States, we integrated Centers for Disease Control and Prevention and state-provided vaccination data, identifying and rectifying discrepancies between these data sources. We found that COVID-19 vaccination coverage in the United States exhibits significant spatial heterogeneity at the county level, and we statistically identified spatial clusters of undervaccination, all with foci in the southern United States. We also identified vaccination progress at the county level as variable through summer 2021; the progress of vaccination in many counties stalled in June 2021, and few had recovered by July, with transmission of the SARS-CoV-2 delta variant rapidly rising. Using a comparison with a mechanistic growth model fitted to our integrated data, we classified vaccination dynamics across time at the county scale. Our findings underline the importance of curating accurate, fine-scale vaccination data and the continued need for widespread vaccination in the United States, especially with the continued emergence of highly transmissible SARS-CoV-2 variants.
Producing investment space: the International Finance Corporation and the geofinancial power network
Authors: Funke Jayson J
Published: April 2022

This article examines the International Finance Corporation (IFC) as an important institutional driver of the financialisation process in developing and emerging economies. An institutional analysis of the Corporation’s development objectives and corporate directives is provided, focussing on its investments, financial institution building operations and its production of new investment spaces, as exemplified in its engineering of ‘emerging markets’ as a novel financial asset class. The IFC is conceptualised as operating within the geofinancial power network, a transnational sociotechnical system that helps demonstrate how the Corporation facilitates financialisation spatially from global centres of power to peripheral spaces in developing and emerging economies.
29: INCIDENCE, DIAGNOSIS AND MANAGEMENT OF MALABSORPTION FOLLOWING OESOPHAGECTOMY: A SYSTEMATIC REVIEW
Authors: Khaw R A , Nevins E J , Phillips A W
Published: April 2022

Background and aim

Survival following oesophagectomy for oesophageal cancer is increasing. This has resulted in increased focus on quality-of-life and improved survivorship. Weight loss and malnutrition occurs in 25–46% of patients after three years, with associated adverse gastrointestinal symptoms. Malabsorption syndrome is multifactorial and includes exocrine pancreatic insufficiency (EPI), small intestinal bacterial overgrowth (SIBO) and bile acid malabsorption (BAM), however there is little literature available in patients following oesophagectomy. The aim of this study was to evaluate the reported incidence and management of malabsorption syndromes post-oesophagectomy.

Methods

A systematic search of PubMed, EMBASE, MEDLINE, Scopus and the Cochrane Library evaluating incidence, diagnosis and management of malabsorption was performed for studies published until March 2021.

Results

Of 461 identified studies, seven studies (6/7 non-randomised observational studies) were included, with a combined population of 344 (range 7–87). Incidence of malabsorption syndromes including EPI, SIBO and BAM were 10.2–100%, 37.8–100% and 3.33–100% respectively. There was no consensus definition for EPI, SIBO or BAM; and there was variation in diagnostic methods. Diagnostic criteria varied from clinical (gastrointestinal symptoms or weight loss), or biochemical (faecal elastase, hydrogen breath test and Selenium-75-labelled synthetic bile acid measurements). Treatment modalities using pancreatic enzyme replacement, rifaximin and colesevelam showed improvement in symptoms and weight in all studies.

Conclusion

Malabsorption syndromes following oesophagectomy are likely to be severely underestimated. The resultant gastrointestinal symptoms have a negative effect on post-operative quality of life. Current literature suggests benefit with outlined therapies, however greater understanding of these conditions, their diagnosis, and management is required to further understand which patients will benefit from treatment.
45: OUTCOMES OF PROLONGED TIME TO SURGERY IN PATIENTS WITH RESIDUAL DISEASE AFTER NEOADJUVANT CHEMORADIOTHERAPY FOR OESOPHAGEAL CANCER
Authors: Overtoom H , Eyck B , Van Der Wilk B , Noordman B , Van Der Sluis P , Wijnhoven B , Van Lanschot J , Lagarde S
Published: April 2022

Background and aim

Standard treatment for locally advanced oesophageal cancer is neoadjuvant chemoradiotherapy (nCRT) plus surgery. Time to surgery (TTS) after nCRT seems safe up to 12 weeks and delaying surgery may improve patient condition and pathological response. However, it is unknown whether prolonged TTS is safe in patients with residual disease. The aim of this study was to investigate whether prolonged TTS leads to inferior surgical outcomes and survival in patients with residual disease after nCRT.

Methods

Patients with pathological residual disease at endoscopy with biopsies 4–6 weeks after nCRT were selected from the preSANO-trial and SANO-trial. Patients were categorized by TTS ≤12 weeks versus TTS >12 weeks after completion of nCRT. Primary endpoint was overall survival (OS). Secondary endpoints were relapse-free survival (RFS), surgery without resection (SWR), microscopically radical resection (R0), tumour regression grade (TRG) and postoperative complications. Effects of TTS on OS and RFS were analysed with Cox regression, adjusted for Charlson comorbidity index (CCI) at baseline, as well as WHO performance score and weight loss after nCRT.

Results

Forty-two patients were included in the TTS >12 weeks group and 132 patients in the TTS ≤12 weeks group. Median follow-up was 20.6 months (IQR 16.1–30.3). For TTS >12 weeks, the adjusted hazard ratios for all-cause mortality was 0.50 (95% CI: 0.24–1.02) and for disease-relapse or mortality was 0.47 (95% CI: 0.25–0.91). The rate of patients with a postoperative complication was higher in the TTS >12 weeks group (89% vs 72%, P = 0.049), but severity of complications was comparable between the groups (Clavien-Dindo ≥3, 46% vs. 29%, P = 0.09), as were rate of SWR (12% vs. 4%, P = 0.14), R0-resections (89% vs 87%, P = 0.89), and TRG-scores (P = 0.97) compared to patients with TTS ≤12 weeks.

Conclusion

Prolonged TTS beyond 12 weeks in patients with residual disease after nCRT did not have a negative effect on OS and on RFS, but was correlated with an increase in postoperative complications.
50: IDENTIFICATION AND CLASSIFICATION OF TUMOR CELLS IN BARRETT’S CARCINOMA PATIENTS BY HYPERSPECTRAL IMAGING (HSI)
Authors: Maktabi M , Wichmann Y , Köhler H , Jansen-Winkeln B , Ahle H , Chalopin C , Thieme R
Published: April 2022

Background and aim

Digital pathology will revolutionize the discriminate of malignant and non-malignant cells in histologically specimens. Hyperspectral imaging (HSI), a new technology combing imaging with spectroscopy might be beneficial for tumor cell identification.

Methods

After resection, specimens (n = 95) were fixed in 4% formaldehyde and slices were conducted (3 μm), which were stained with haematoxylin and eosin (HE). Esophageal adenocarcinoma, tumor stroma, squamous epithelium cells and background were recorded by HSI between the visual and near-infrared light (500-1000 nm). A multi-layer perceptron with 2 hidden layers was used for discrimination.

Results

We were able to record esophageal adenocarcinoma, tumor stroma and squamous epithelium cells by HSI. Differences in the absorbance of squamous epithelium and esophageal adenocarcinoma cells were determined at eosin’s and hematoxilin’s maximal absorption of 524 nm and 630 nm. For all classifiers, the esophageal adenocarcinoma cells, the tumor stroma cells, the squamous epithelium and the background, the intra group variances were quite low. 412,964 spectra of EAC cells, 32,318 spectra of tumor stroma cells and 55,711 spectra of squamous epithelium cells were measured and analyzed for classification. MLP revealed an accuracy of 71% for EAC and stroma cells and 73% for squamous epithelium cells.

Conclusion

Squamous epithelium and esophageal adenocarcinoma cells show specific spectral alterations due to their HE-staining, when measured by HSI. However, the sensitivities and specificities was quiet high. For implementation in daily routine procedures, the training algorithms need to be validated to foster a semi-automatic decision-making process in histopathological tumor cell identification.
62: WHICH GASTRIC CANCER PATIENTS COULD BENEFIT FROM STAGING LAPAROSCOPY? A GIRCG MULTICENTER COHORT STUDY
Authors: Solaini L , Bencivenga M , D’Ignazio A , Milone M , Marino E , De Pascale S , Rosa F , Sacco M , Fumagalli Romario U , Graziosi L , De Palma G , Marrelli D , Morgagni P , Ercolani G
Published: April 2022

Background and aim

Staging laparoscopy is an important step of the staging of gastric cancer patients, however, its indication are universally accepted by the different guidelines.This study aimed to define those factors which could help in defining the most appropriate use of staging laparoscopy in a western population.

Methods

A retrospective cohort study was carried out, including 330 (226 cM- and 104 cM+) gastric cancer patients who had undergone staging laparoscopy between 2010–2020 in seven GIRCG centers. A model including easily-accessible clinical, biochemical and pathological markers was constructed to predict the risk of carcinomatosis. ROC curve and decision curve analyses were used to verify its accuracy and net benefit.

Results

In the cM- population staging laparoscopy could detect 70 cases who had peritoneal carcinomatosis or positive cytology, for a yield of 31.0%. In cM+ patients staging laparoscopy could exclude carcinomatosis in 15 cases. In cM- patients, intestinal type tumors (0.36, 0.14–0.92; P = 0.035), the presence of signet ring cells (2.58, 1.04–6.33; P = 0.039) and cancers of the upper third (3.36, 1.43–7.92; P = 0.005) were associated with the presence of peritoneal carcinomatosis and/or positive cytology. The ROC curve analysis of the model including the three variables showed an AUC of 0.75 (0.66–0.80, P < 0.001). The decision curve analyses showed that the model had a higher net benefit than the treating all strategy between threshold probabilities of 16 and 50%.

Conclusion

Staging laparoscopy is a useful tool to address the patient with gastric cancer to the most adequate treatment. In cM- patients the assessment of the location of the tumor, the Lauren’s histotype and the presence of signet ring cells may help in providing additional elements in indicating or not the use of staging laparoscopy.
90: HOSPITAL VARIATION IN FAILURE TO CURE IN ESOPHAGEAL CANCER SURGERY: IS THE PROPORTION OF PATIENTS UNDERGOING SURGERY PER HOSPITAL PIVOTAL?
Authors: Voeten D M , Vissers P A , Verhoeven R H , Van Hillegersberg R , Van Berge Henegouwen M I
Published: April 2022

Background and aim

The proportion of potentially curable esophageal cancer patients undergoing surgery varies among hospitals. Failure to cure is a composite outcome describing surgery not meeting its aim: (1) non-resectional surgery, (2) non-radical surgery (R1/R2) or (3) postoperative mortality. This study hypothesized that hospitals offering surgery to many patients have higher failure-to-cure rates. It aimed to investigate the relationship between the proportion of potentially curable esophageal cancer patients undergoing surgery and failure-to-cure rates.

Methods

From the Netherlands Cancer Registry, all patients with cT1-cT4a/cTx-any cN-cM0 esophageal cancer diagnosed in 2015–2018 were included. For each region surrounding a surgical center, the expected proportion of patients undergoing surgery was established using multivariable analyses and divided by the observed proportion computing the O/E ratio. Hospitals were categorized into tertiles based on their tendency to treat patients surgically (O/E ratio). The association between these hospital groups and failure to cure was investigated using multilevel multivariable regression analyses.

Results

In total, 3,437 (53.2%) of 6,457 potentially curable patients underwent surgery, ranging from 45–64% among 16 hospitals. The overall failure-to-cure rate was 15.0% (hospital variation [4.6%–23.7%]). After categorizing, 1,003 patients underwent surgery in hospitals treating relatively few patients surgically (O/E ratio < 0.94), 1,297 patients in average hospitals and 1,137 patients in hospitals treating many patients surgically (O/E ratio > 1.01). Failure-to-cure rates were 16.8%, 12.2% and 14.0%, respectively. This was non-significant in multilevel analyses (aOR:0.63, 95%CI:0.38–1.05; aOR:0.76, 95%CI:0.46–1.24) (Table 1).

Conclusion

Failure-to-cure rates were not significantly higher in hospitals with a high percentage of surgery, suggesting that increasing the surgery rate may be beneficial.

Table

http://uploadfile.sem-2000.it/OLC/file/9203828791100911681076702/93673_Table.JPG.
96: EXPERIENCE IN RECONSTRUCTION OF LARYNGOPHARYNGOESOPHAGECTOMIES IN A THIRD LEVEL CENTER
Authors: Navío-Seller A , Abelló-Audí D , Bruna-Esteban M , Vaqué-Urbaneja J , Mingol-Navarro F
Published: April 2022

Background and aim

Pharyngoesophageal reconstruction after laryngo-pharyngo-esophagectomy is challenging due to its high morbidity and mortality. There are different reconstructive flaps: visceral flaps (pedicle stomach and colon flaps and free jejunum or colon grafts) and myocutaneous flaps (pedicle local flaps or free grafts). The objective is to evaluate the morbidity and mortality and functional results of the reconstruction after laryngo-pharyngo-esophagectomy.

Methods

This is a retrospective study of patients who underwent laryngo-pharyngo-esophagectomy in our center, due to a benign cause (caustic ingestion) or malignant (larynx, pharynx, parathyroid and cervical esophagus cancer) with circumferential pharyngeal reconstruction with flap, from 2008 to 2020. Demographic variables, procedure performed and flap used for reconstruction, complications related to reconstruction (fistula, stenosis, necrosis), postoperative complications, days until adequate swallowing, flap’s functional result, hospital stay, recurrence and mortality were collected.

Results

Twelve patients, with 59 years (45–78) median age, underwent surgery. There were complications related to reconstruction in 42% of the patients (Table 1). Postoperative morbidity was 67%. The median hospital stay was 21 days (16–94). The median time to swallowing was 13 days (3–73). An optimal functional result (oral intake) was achieved in 75%. The median follow-up was 18 months (4–56), with a survival rate of 50%. 30-days mortality was 8%.

Conclusion

Our study shows a high morbidity and mortality after circumferential pharyngeal reconstruction, similar to literature published. We have observed a higher rate of reconstruction related complications and worse functional results in reconstructions performed with gastroplasty and coloplasty after total laryngo-pharyngo-esophagectomy, compared to less aggressive local resections with ALT free flap reconstruction.

Table

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100: IMPACT OF INCREASING LYMPH NODE YIELD ON THE NUMBER OF POSITIVE LYMPH NODES, MORBIDITY AND SURVIVAL IN ESOPHAGEAL CANCER SURGERY
Authors: Henckens S , Hagens E , Eshuis W , Meijer S , Van Berge Henegouwen M , Gisbertz S
Published: April 2022

Background and aim

Accurate determination of lymph node status after esophagectomy requires complete lymphadenectomy. Extended surgery might also lead to more postoperative morbidity. This study analyzed lymph node yield over time and investigated the influence of lymph node yield on the number of positive lymph nodes, postoperative morbidity and disease-free survival.

Methods

Patients who underwent transthoracic esophagectomy for esophageal adenocarcinoma between 2010 and 2018, were included. Lymph node yield was both analyzed as continuous variable and as categorical variable (<15, 15–29 (reference category) and ≥ 30 nodes). The effect of lymph node yield on the number of positive lymph nodes, morbidity and disease-free survival was assessed in multivariable regression analyses.

Results

A total of 469 patients were included with a median follow-up of 20 months. The majority of the included patients received neoadjuvant chemo(radio)therapy (93.1%). The median lymph node yield increased from 25.0 lymph nodes (IQR 20–34) in 2010 to 36.0 lymph nodes (IQR 30–45) in 2018. Higher lymph node yield was significantly associated with more positive lymph nodes both as continuous variable (IRR 1.020, 95%CI 1.006–1.034), and as categorical variable with a threshold of ≥30 nodes (IRR 1.549, 95%CI 1.069–2.244). Lymph node yield was not associated with morbidity. Lymph node yield was not associated with disease-free survival when analyzed as a continuous variable (HR 0.996, 95%CI 0.984–1.008). There was also no difference in disease-free survival between patients with a lymph node yield of <15 and 15–29 (reference) (HR 1.362, 95%CI 0.793–2.338), and between patients with a lymph node yield of 15–29 (reference) and ≥ 30 (HR 0.849, 95%CI 0.650–1.109).

Conclusion

A higher lymph node yield after esophagectomy was associated with a higher number of positive lymph nodes; a higher number of resected lymph nodes therefore improves staging. A higher lymph node yield did not result in increased morbidity and no association between lymph node yield and disease-free survival could be demonstrated in patients undergoing esophagectomy after neoadjuvant chemo(radio)therapy.
104: PERIOPERATIVE STRATEGIES IN ESOPHAGEAL CANCER RESECTION IN 12 NORDIC UNIVERSITY HOSPITALS
Authors: Achiam M P , Nilsson M , Åkesson O , Johansson J , Edholm D , Lindblad M , Szabo E , Sundbom M , Lindberg F , Bau Mortensen M , Kjus Aahlin E , Mala T , Johannessen H , Johnsen G , Kauppila J , Hedberg J
Published: April 2022

Background and aim

The Nordic countries have similar health care systems and registries simplifying epidemiological research. Differences in treatment traditions can, however, hamper the possibility to assess results and to harmonize control arms in joint randomized trials. In the process to set up a Nordic multi-center randomized trial regarding use of nasogastric tube (NG-tube) decompression after esophagectomy, we aimed to investigate perioperative routines in 12 University Hospitals in Sweden, Denmark, Norway and Finland.

Methods

All Nordic University Hospitals were contacted regarding a Nordic randomized controlled trial exploring effects and complications associated with the use of nasogastric tube use after esophagectomy for cancer. Those who chose to join the trial were sent a questionnaire regarding surgical and perioperative routines.

Results

Twelve centers with a combined catchment area of 16 million inhabitants and an annual volume of 400 esophagectomies joined the trial network. All but one used totally minimally invasive or hybrid surgical approach. All 12 centers reported routine use of NG-tube and 5 employed continuous suction. The NG-tube was removed between 3 and 7 days postoperatively. A routine pylorus drainage procedure was reported from two centers. Jejunostomy was used universally in 5 centers and selectively in 6 centers. One center did not use jejunostomy.

Conclusion

Differences in perioperative care after esophagectomy is apparent in the Nordic countries, highlighting the need for high-level evidence regarding these practices. A unified approach may facilitate clinical trial initiatives. There is a paucity of evidence regarding optimal NG-tube use after esophagectomy for cancer and a randomized trial investigating this issue is under way.
105: SURGICAL DISSECTION DOES NOT INCREASE FREE CANCER CELLS (FCC) IN PERITONEAL LAVAGE OF PATIENTS FOLLOWING D2 GASTRECTOMY
Authors: Geca K , Rawicz-Pruszynski K , Sedlak K , Mlak R , Polkowski W
Published: April 2022

Background and aim

Peritoneal free cancer cells (FCC) in patients with gastric cancer (GC) is poor prognostic factor. D2 gastrectomy dissection may induce exfoliated FCC spread from primary tumour or involved lymph nodes (LN). Conventional cytology for FCC detection has several limitations, and prophylactic use of extensive intraoperative peritoneal lavage (IPL) does not improve survival. A prospective single-arm observational study was conducted to verify whether D2 gastrectomy causes an increase of FCC in peritoneal lavage as in patients with GC following D2 gastrectomy.

Methods

Thirty GC patients underwent D2 gastrectomy, followed by objective quantitative measurements of CK19 mRNA level reflecting FCC with One-Step Nucleic Acid Amplification (OSNA) assay. The IPL with 3000 cc of saline was performed twice after: (1) gastrectomy with D2 lymphadenectomy; and (2) alimentary tract reconstruction. The IPL samples were analysed by initial cytology and four (1–4) consecutive OSNA assays (Figure 1). Three patients were excluded due to positive cytology in samples obtained after laparotomy.

Results

Initial OSNA measurement (1) revealed positive results (≥24.6 cCP/μl) in 7 (29.6%) patients. Subsequent OSNA measurements revealed a significant decrease in the FCC level after removal of the primary tumour with regional LNs (D2 gastrectomy) (1 vs 2; medians [95%CI]: 4.6 [1.1–18.5] vs. 0.00004 [0–0.2] cCP/μl; P = 0.0012). The first IPL induced non-significant increase in the FCCs (2 vs 3, medians [95%CI]: 0.00004 [0–0.2] vs 0 [0–0.5] cCP/μl; P = 0.3300), but the second IPL reversed it to normal levels (3 vs 4, medians [95%CI]: 0 [0–0.5] vs 0 [0–0] cCP/μl; P = 0.0.0574). At this point of operation, additional finding was a trend toward temporal increase of FCC in patients with LN involvement (pN1–3)(2 vs 3; medians [95%CI]: 0 [0–0.2] vs 0 [0–42.8] cCP/μl; P = 0.0674). One patient was still positive (FCC) at the end of operation as measured by OSNA (4).

Conclusion

D2 Gastrectomy does not induce increase in the peritoneal FCCs. Temporal intraoperative increase in peritoneal FCC after the IPL may be observed, especially in tumours with LN metastases. At least two consecutive IPLs (with min. 3000 mL of saline) are necessary to reverse temporal increase of peritoneal FCC.