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Monte Carlo method for evaluation of surface emission rate measurement uncertainty

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Nuclear Science and Techniques 2024年第7期35卷 126-136页

作者： Yuan-Qiao Li Min Lin Li-Jun Xu Rui Luo Yu-He Zhang Qian-Xi Ni Yun-Tao Liu China Institute of Atomic Energy Beijing102413China National Key Laboratory for metrology and Calibration Techniques Beijing102413China department of radiation Oncology Hunan Cancer HospitalChangsha410031China The Affiliated Cancer Hospital of Xiangya School of Medicine Central South UniversityChangsha410031China

The aim of this study is to evaluate the uncertainty of 2πα and 2πβ surface emission rates using the windowless multiwire proportional counter *** study used the Monte Carlo method (MCM) to validate the conventional Guide to the Expression of Uncertainty in Measurement (GUM) method.A dead time measurement model for the two-source method was established based on the characteristics of a single-channel measurement system,and the voltage threshold correction factor measurement function was indirectly obtained by fitting the threshold correction *** uncertainty in the surface emission rate was calculated using the GUM method and the law of propagation of *** MCM provided clear definitions for each input quantity and its uncertainty distribution,and the simulation training was realized with a complete and complex mathematical *** results of the surface emission rate uncertainty evaluation for four radioactive plane sources using both methods showed the uncertainty’s consistency E_(n)<0.070 for the comparison of each source,and the uncertainty results of the GUM were all lower than those of the ***,the MCM has a more objective evaluation process and can serve as a validation tool for GUM results.

关键词： Surface emission rate Monte Carlo method metrology Probability distribution function Dead time Low-energy loss correction Least-squares method

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Rapid monitoring of indoor airborne influenza and coronavirus with high air flowrate electrostatic sampling and PCR analysis

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Frontiers of Environmental Science & Engineering 2024年第7期18卷 73-85页

作者： Sanggwon An Sangsoo Choi Hyeong Rae Kim Jungho Hwang School of Mechanical Engineering Yonsei UniversitySeoul 02876Republic of Korea Gas metrology Group Korea Research Institute of Standards and Science(KRISS)Daejeon 34113Republic of Korea

The World Health Organization has raised concerns about the possibility of airborne transmission in enclosed and poorly ventilated ***,rapid monitoring of airborne viruses is necessary in multi-use facilities with dense ***,an electrostatic air sampler(250 L/min)was developed in this work to obtain indoor viral aerosol samples for analysis via the Polymerase Chain Reaction(PCR).Aerosol tests with H1N1 and HCoV-229E were performed to evaluate the sample collection *** analysis,along with another aerosol test,was conducted to evaluate the recovery of the virus particles collected by the *** laboratory tests,our electrostatic sampler obtained viral samples that were detectable by PCR under the simulated viral pandemic scenario(3000 RNA copies per cubic meter of air)within 40 *** resulting cycle threshold(C)values were 35.07 and 37.1 for H1N1 and HCoV-229E,*** the performance evaluation in the laboratory,field tests were conducted in a university classroom from October 28 to December 2,*** A and HCoV-229E were detected in two air samples,and the corresponding C,values were 35.3 and *** PCR results are similar to those obtained from laboratory tests,considering the simulatedviralpandemic scenario.

关键词： Airborne virus Electrostatic sampler Rapid monitoring Indoor environment Field test

Nano-sized stationary phase packings retained by single-particle frit for microchip liquid chromatography

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Chinese Chemical Letters 2024年第4期35卷 486-489页

作者： Wangyan Hu Ke Li Xiangnan Dou Ning Li Xiayan Wang Center Excellence for Environmental Safety and Biological Effects Beijing Key Laboratory for Green Catalysis and SeparationDepartment of ChemistryBeijing University of TechnologyBeijing 100124China Center for Environmental metrology National Institute of MetrologyBeijing 100029China

Modern chromatography is increasingly focused on miniaturization and integration. Compared to conventional liquid chromatography, microfluidic chip liquid chromatography(microchip-LC) has the potential due to its zero-dead volume connection and ease of integration. Nano-sized packings have the potential to significantly enhance separation performance in microchip-LC. However, their application has been hindered by packing difficulties. This study presents a method for packing nano-sized silica particles into a microchannel as the stationary phase. The microchip-LC packed column was prepared by combining the weir and the porous silica single-particle as frit to retain the packing particles. A surface tensionbased single-particle picking technique was established to insert porous single-particle frit into glass microchannels. Additionally, we developed a slurry packing method that utilizes air pressure to inject nano-sized packing into the microchannel. Pressure-driven chromatographic separation was performed using this nano-packed column integrated into a glass microchip. The mixture of four PAHs was successfully separated within just 8 min using a 5 mm separation channel length, achieving high theoretical plates(10~6plates/m). Overall, these findings demonstrate the potential of utilizing nano-sized packings for enhancing chromatographic performance in microchip systems.

关键词： Nano-size packing Single-particle frit Packed column Microchip LC Chromatographic separation

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Dynamic Scene Graph Generation of Point Clouds with Structural Representation Learning

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Tsinghua Science and Technology 2024年第1期29卷 232-243页

作者： Chao Qi Jianqin Yin Zhicheng Zhang Jin Tang School of Artificial Intelligence Beijing University of Posts and TelecommunicationsBeijing 100876China Standard and metrology research Institute China Academy of Railway Sciences Corporation LimitedBeijing 100081China

Scene graphs of point clouds help to understand object-level relationships in the 3D *** graph generation methods work on 2D structured data,which cannot be used for the 3D unstructured point cloud *** point-cloud-based methods generate the scene graph with an additional graph structure that needs labor-intensive manual *** address these problems,we explore a method to convert the point clouds into structured data and generate graphs without given ***,we cluster points with similar augmented features into groups and establish their relationships,resulting in an initial structural representation of the point ***,we propose a Dynamic Graph Generation Network(DGGN)to judge the semantic labels of targets of different *** dynamically splits and merges point groups,resulting in a scene graph with high *** show that our methods outperform other baseline *** output reliable graphs describing the object-level relationships without additional manual labeled data.

关键词： scene graph generation structural representation point cloud

Extending microwave-frequency electric-field detection through single transmission peak method

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Chinese Physics B 2024年第5期33卷 417-423页

作者：刘青陈进湛王赫张杰阮伟民伍国柱郑顺元罗景庭宋振飞 College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060China Shenzhen Institute for Technology Innovation National Institute of MetrologyShenzhen 518107China Center for Advanced Measurement Science National Institute of MetrologyBeijing 100029China

The strength of microwave(MW)electric field can be observed with high precision by using the standard electromagnetically induced transparency and Aulter–Towns(EIT-AT)technique,when its frequency is resonant or nearly-resonant with the Rydberg transition *** the detuning of MW field increases,one of the transmission peaks(single peak)is easier to measure due to its increased *** can be found that the central symmetry point of the two transmission peaks f_(1/2)is only related to the detuning of MW field△_(MW)and central symmetry point f_(0)of resonant MW field,satisfying the relation f_(1/2)=△_(MW)/2+f_(0).Thus,we demonstrate a single transmission peak method that the MW E-field can be determined by interval between the position of single peak and f_(1/2).We use this method to measure continuous frequencies in a band from-200 MHz to 200 MHz of the MW *** experimental results and theoretical analysis are presented to describe the effectiveness of this *** 50 MHz<△_(MW)<200 MHz,this method solves the problem that the AT splitting cannot be measured by using the standard EIT-AT techniques or multiple atomic-level Rydberg atom schemes.

关键词： microwave electric field Rydberg atom electromagnetically induced transparency(EIT) Aulter-Towns splitting

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Structural insight into palladium-nickel clusters over mordenite zeolite for carbene-insertion reaction

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Frontiers of Chemical Science and Engineering 2024年第9期18卷 89-99页

作者： Guangchao Li Ping-Luen Baron Ho Bryan Kit Yue Ng Tai-Sing Wu Pawel Rymarz Shik Chi Edman Tsang department of Applied Biology and Chemical Technology The Hong Kong Polytechnic UniversityHong Kong 999077China department of Chemistry University of OxfordOxford OX13QRUK Synchrotron radiation research Center Hsinchu 30076China

The advancement of heterogeneous catalysts incorporating metal clusters in the nanometric size range has garnered significant attention due to their extraordinary catalytic activity and *** detailed characterization and understanding of the atomic structure of these metal clusters within catalysts is crucial for elucidating the underlying reaction *** the present study,a distinctive three-atom PdNi cluster,characterized by two Pd atoms at terminal positions and a central Ni atom,was synthesized over mordenite *** presence of atomic PdNi clusters within the eight-membered ring side pocket area was confirmed by multiple advanced analytical techniques,including magic-angle spinning nuclear magnetic resonance spectroscopy,synchrotron X-ray powder diffraction,extended X-ray absorption fine structure spectroscopy,and high-angle annular dark-field scanning transmission electron *** catalytic activity of the confined active species was examined by the carbene-mediated reactions of ethyl-2-diazoacetate to ethyl-2-methoxyacetate as a model *** to the Pd-mordenite and Ni-mordenite,the PdNi-mordenite catalyst incorporates a PdNi cluster,which demonstrates a superior performance,achieving 100%conversion and high selectivity under the same reaction *** study elucidates the potential of constructing bimetallic clusters in zeolites,providing valuable insights for developing new heterogeneous catalysts applicable to a wide range of catalytic processes.

关键词： zeolite metal cluster synchrotron X-ray diffraction carbene-mediated reaction

STING agonist-conjugated metal-organic framework induces artificial leukocytoid structures and immune hotspots for systemic antitumor responses

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National Science Review 2024年第07期 189-204页

作者： Taokun Luo Xiaomin Jiang Yingjie Fan Eric Yuan Jinhong Li Langston Tillman Wenbin Lin department of Chemistry University of Chicago department of radiation and Cellular Oncology and the Ludwig Center for Metastasis research University of Chicago

Radiotherapy is widely used for cancer treatment, but its clinical utility is limited by radioresistance and its inability to target metastases. Nanoscale metal-organic frameworks(MOFs) have shown promise as high-Z nanoradiosensitizers to enhance radiotherapy and induce immunostimulatory regulation of the tumor microenvironment. We hypothesized that MOFs could deliver small-molecule therapeutics to synergize with radiotherapy for enhanced antitumor efficacy. Herein, we develop a robust nanoradiosensitizer,GA-MOF, by conjugating a STING agonist, 2,3-cyclic guanosine monophosphate–adenosine monophosphate(GA), on MOFs for synergistic radiosensitization and STING activation. GA-MOF demonstrated strong anticancer efficacy by forming immune-cell-rich nodules(artificial leukocytoid structures) and transforming them into immunostimulatory hotspots with radiotherapy. Further combination with an immune checkpoint blockade suppressed distant tumors through systemic immune activation. Our work not only demonstrates the potent radiosensitization of GA-MOF, but also provides detailed mechanisms regarding MOF distribution, immune regulatory pathways and long-term immune effects.

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GAN‐MD:A myocarditis detection using multi‐channel convolutional neural networks and generative adversarial network‐based data augmentation

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CAAI Transactions on Intelligence Technology 2024年第4期9卷 866-878页

作者： Hengame Ahmadi Golilarz Alireza Azadbar Roohallah Alizadehsani Juan Manuel Gorriz department of Medical radiation Engineering Faculty of EngineeringLahijan BranchIslamic Azad UniversityLahijanIran department of Medical radiation Engineering Lahijan BranchIslamic Azad UniversityLahijanIran Institute for Intelligent Systems research and Innovation(IISRI) Deakin UniversityWaurn PondsVictoriaAustralia Data Science and Computational Intelligence Institute University of GranadaGranadaSpain

Myocarditis is a significant public health concern because of its potential to cause heart failure and sudden *** standard invasive diagnostic method,endomyocardial bi-opsy,is typically reserved for cases with severe complications,limiting its widespread ***,non‐invasive cardiac magnetic resonance(CMR)imaging presents a promising alternative for detecting and monitoring myocarditis,because of its high signal contrast that reveals myocardial *** assist medical professionals via artificial intelligence,the authors introduce generative adversarial networks‐multi discriminator(GAN‐MD),a deep learning model that uses binary classification to diagnose myocarditis from CMR *** approach employs a series of convolutional neural networks(CNNs)that extract and combine feature vectors for accurate *** authors suggest a novel technique for improving the classification precision of *** generative adversarial networks(GANs)to create synthetic images for data augmentation,the authors address challenges such as mode collapse and unstable *** a reconstruction loss into the GAN loss function requires the generator to produce images reflecting the discriminator features,thus enhancing the generated images'quality to more accurately replicate authentic data ***,combining this loss function with other reg-ularisation methods,such as gradient penalty,has proven to further improve the perfor-mance of diverse GAN models.A significant challenge in myocarditis diagnosis is the imbalance of classification,where one class dominates over the *** mitigate this,the authors introduce a focal loss‐based training method that effectively trains the model on the minority class *** GAN‐MD approach,evaluated on the Z‐Alizadeh Sani myocarditis dataset,achieves superior results(F‐measure 86.2%;geometric mean 91.0%)compared with other deep learning models and traditional machine learning methods.

关键词： 2‐D 3‐D

Prediction of pathological complete response and prognosis in locally advanced rectal cancer

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World Journal of Gastrointestinal Oncology 2024年第6期16卷 2520-2530页

作者： Yi-Jun Xu Dan Tao Song-Bing Qin Xiao-Yan Xu Kai-Wen Yang Zhong-Xu Xing Ju-Ying Zhou Yang Jiao Li-Li Wang department of radiation Oncology The First Affiliated Hospital of Soochow UniversitySuzhou 215006Jiangsu ProvinceChina department of radiation Oncology The Fourth Affiliated Hospital of Soochow UniversitySuzhou 215006Jiangsu ProvinceChina School of radiation Medicine and Protection Medical College of Soochow UniversitySuzhou 215123Jiangsu ProvinceChina

BACKGROUND Colorectal cancer is currently the third most common malignant tumor and the second leading cause of cancer-related death *** chemoradiotherapy(nCRT)is standard for locally advanced rectal cancer(LARC).Except for pathological examination after resection,it is not known exactly whether LARC patients have achieved pathological complete response(pCR)before *** date,there are no clear clinical indicators that can predict the efficacy of nCRT and patient *** To investigate the indicators that can predict pCR and long-term outcomes following nCRT in patients with *** Clinical data of 128 LARC patients admitted to our hospital between September 2013 and November 2022 were retrospectively *** were categorized into pCR and non-pCR *** analysis(using the χ^(2) test or Fisher’s exact test)and logistic multivariate regression analysis were used to study clinical predictors affecting *** 5-year disease-free survival(DFS)and overall survival(OS)rates were calculated using Kaplan-Meier analysis,and differences in survival curves were assessed with the log-rank *** Univariate analysis showed that pretreatment carcinoembryonic antigen(CEA)level,lymphocyte-monocyte ratio(LMR),time interval between neoadjuvant therapy completion and total mesorectal excision,and tumor size were correlated with *** results showed that CEA≤5 ng/mL(P=0.039),LMR>2.73(P=0.023),and time interval>10 wk(P=0.039)were independent predictors for *** analysis demonstrated that patients in the pCR group had significantly higher 5-year DFS rates(94.7%vs 59.7%,P=0.002)and 5-year OS rates(95.8%vs 80.1%,P=0.019)compared to the non-pCR *** deposits(TDs)were significantly correlated with shorter DFS(P=0.002)and OS(P<0.001).CONCLUSION Pretreatment CEA,LMR,and time interval contribute to predicting nCRT efficacy in LARC *** pCR demonstrates longer DFS and *** correlate with poor pr

关键词： Locally advanced rectal cancer Neoadjuvant chemoradiotherapy Pathological complete response Carcinoembryonic antigen Inflammation-related markers Tumor deposit Prognosis