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IN738LC alloy is a typical γ’ phase precipitation-strengthened nickel-based superalloy, commonly used in high-temperature components such as gas turbines and aero-engines.In order to further enhance its high-temperature wear resistance, IN738 alloy samples were prepared using laser cladding technology with four different laser powers in a 99.99%pure nitrogen environment, followed by heat treatment at 850 ℃for 24 h.The microstructure and properties were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), high-temperature friction and wear testing machines and JMatPro software.Results showed that with the increase in laser power, the mean hardness of the samples without heat treatment increased gradually from 40.74 HRC to 41.92 HRC, while the mean hardness of the samples after heat treatment was 43.0 HRC.The average friction coefficients of the samples without heat treatment and after heat treatment at normal temperature were 0.70 and 0.65, respectively.The average friction coefficient at 800 ℃of the samples after heat treatment was 0.35.The wear resistance of the samples first increased and then decreased with the increase in laser power within a certain range of laser power.The wear resistance of the samples prepared at room temperature and at 800 ℃was highest when the laser power was 750 W and 650 W,respectively.The wear resistance of samples prepared under the same laser power at a high temperature of 800 ℃was much better than that at room temperature.

Objective To explore the the potential risks of antiretroviral therapy(ART) drugs on blood safety among blood donors in Shenzhen. Methods High pressure liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) was used to measure ART drugs concentrations in the plasma of regular blood donors (negative control group, n=86) and anti-HIV positive individuals (experimental group, n=98, detected from approximately 440 000 blood donors during 2019—2023). The baseline plasma concentrations of ART drugs in the negative control group were clarified, and the impact of ART drugs on blood safety was analyzed. Results The baseline concentrations of ART drugs were not detected in 86 samples of negative control group. Four positive ART drugs samples were detected in 1∶2 pooled plasma samples of 98 anti-HIV positive blood donors plasma in the resolution test. The ART positive rate of anti-HIV positive donors was 4.08%, with tenofovir, lamivudine and efavirenz detected in three blood donors and lamivudine, lopinavir, ritonavir and zidovudine detected in one blood donor. Conclusion ART drugs were found among anti-HIV positive blood donors in Shenzhen. Additional research is needed to investigate the motivation of these specific donors, so as to ascertain the groups most susceptible to potential risks, and guarantee blood safety.

This is an article in the field of earth sciences. The copper resources in Ningxia are relatively poor, and 15 copper producing areas have been basically identified, of which 6 deposits have been explored, and the accumulative amount of copper metal has been identified as 29210.71 tons. There are two types of copper deposits: epigenetic medium-low temperature hydrothermal deposit and placer deposit. The mineralization process is magmatism, sedimentation,ore-bearing fluid process (non-magmatic-non-metamorphic process). Copper deposits are mainly distributed in Weining Beishan area, Xiangshan area, South West Huashan area and the southern area of Liupan Mountain. The metallogenic ages are Caledonian, Varissian, Indosinian and Yanshanian, mainly Caledonian and Yanshanian. According to the study on the metallogenic geological law of the existing deposits, the magmatic hydrothermal type and continental sedimentary type are taken as the key prediction types. According to the material composition of the ore-forming series, five ore-forming series related to copper are determined, and the ore-forming genealogy of copper ore is summarized. The research on metallogenic regularity of copper ore is improved. It provides a theoretical basis for the potential evaluation and prediction of copper resources in Ningxia.

Objective To investigate asymptomatic infection of hepatitis B virus(HBV) among hepatitis B vaccinated donors in Shenzhen, and analyze its serological and molecular characteristics. Methods The HBsAg ELISA positive blood samples of blood donors born after 1992 were collected. HBsAg, anti-HBs, HBeAg, anti-HBe and anti-HBc were further detected by Roche electrochemiluminescence immunoassay (ECL). BCP/PC and S regions were amplified by Nested-PCRs, HBV DNA quantification were adopted by qPCR simultaneously, and the sequences were also analyzed. Results A total of 46 632 blood samples of donors(31 612 males and 15 020 females) from December 2020 to January 2022 collected, and 99 samples with HBsAg ELISA positive were screened out. After tested by ECL, Nested-PCRs, and real-time fluorescence PCR, 61 were confirmed HBsAg positive, with the positive rate at 0.13% (61/46 632), including 49 males (0.16%, 49/31 612) and 12 females (0.08%, 12/15 020). The HBsAg positive rate of males was higher than that of females (P

Objective To analyze the results of different methods for reactive samples screened by the enzyme linked immunosorbent assay (ELISA) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in blood donors. Methods From March to April 2020, a total of 8 632 blood samples in Shenzhen were screened for SARS-CoV-2 total antibodies (TAb, including IgG, IgM, IgA) in plasma using ELISA(PC group), the antibody reactivity samples and their follow up plasma samples (FC group), and samples of disease control group(DC group) from January to April 2020 were detected using the following methods: 1) ELISA method for detecting IgG, IgM, and (or without detection) TAb; 2) pseudovirus neutralizing antibody test(pVNT); 3) western blot (WB) of SARS-CoV-2 antibody. The negative control group(NC group) from February to April 2020 performed ELISA and WB testing. Results Among the 34 total antibody positive samples, 2 were positive for pVNT test, and the total antibody, IgG and WB in the initial screening and tracking testing were positive. Thereafter, it was determined to be confirmed positive. The other 2 cases were positive for pVNT test, while the samples with positive WB results were in the follow-up stage. The TAb, IgG, and pVNT results did not conform to the dynamic evolution of antibodies, and cannot be determined as confirmed positive. Conclusion The infection status of antibody reactivity samples screened by SARS-CoV-2 ELISA can be judged by the logic of pVNT, WB and the dynamic change of antibody.

Objective To establish a magnetic bead enrichment strategy for the detection of human immunodeficiency virus deoxyribonucleic acid (HIV DNA) in peripheral blood, and to verify the improvement of the sensitivity of this method for the detection of HIV DNA in HIV infected patients after early antiretrovital treatment (ART). Methods Peripheral whole blood was collected at 4 timepoints in one ART HIV window period (WP) patient. Peripheral blood mononuclear cells (PBMCs) were isolated on a Ficoll gradient. CD4+ T lymphocytes were enriched from total PBMCs by negative sorting. HIV DNA concentration in magnetic beads enriched group and whole blood group was detected by HIV DNA detection kit. Results CD4+ T cells were isolated by magnetic beads and identified by FCM for purity at (96.4 ± 2.6)%. The viability was (95.9 ± 2.9)%, as demonstrated by trypan blue staining. The person on continued ART treatment in this study had significantly greater reduction in HIV viral load and undetectable HIV plasma RNA at follow up timepoint 4. No HIV DNA was detected in the whole blood group at all 4 timepoints. The quantitative results of HIV DNA in the CD4+ T lymphocyte group of the magnetic bead enrichment group were 73.4, 429.3, 137.1, 449.9 copies/106 CD4+ T cell′s respectively. Conclusion The magnetic bead enrichment method can be more sensitive in detecting the limit low copy HIV DNA in blood samples, and provide early confirmatory data for HIV WP infection and breakthrough infection after ART treatment.

Objective To analyze the SARS-CoV-2 detection results among blood donors in different periods of COVID-19 pandemic control in Shenzhen and assess the antibody levels and infection status of blood donors in different periods, so as to provide reference for subsequent blood testing strategies. Methods A total of 4 768 plasma samples of blood donors were subjected to pooled testing by nucleic acid testing(NAT) with 8 samples per pool. Additionally, these samples were subjected to a 1000-fold dilution, and the detection of SARS-CoV-2 total antibody was performed by enzyme-linked immunosorbent assay (ELISA). The 4 768 plasma samples were collected from blood donors at different time points in Shenzhen, with inquiries made to determine whether donors during the COVID-19 pandemic were in the convalescence. The antibody positive rates in blood screening samples during different periods of the pandemic and samples from individuals in the convalescence of COVID-19 infection were analyzed. Furthermore, the antibody levels were examined for differences based on gender, age, and blood type. Results All 4 768 plasma samples from blood donors were negative by NAT, while 2 342 samples were detected positive by the SARS-CoV-2 total antibody detection, with a positive rate of 49.1%. These samples from four periods (September 30 to October 3, 2022; November 3 to 6, 2022; December 27 to 31, 2022; January 6 to 18, 2023) were subjected to a 1 000-fold dilution for COVID-19 antibody detection, and the positive rates were 21.3%, 15.8%, 65.9%, and 93.9%, respectively. Conclusion The prevalence of COVID-19 antibodies among blood donors in Shenzhen during different periods of the pandemic varied significantly. There was no difference in antibody prevalence among different genders and blood types, while younger individuals exhibited a higher prevalence of antibodies. The risk of COVID-19 transmission through blood transfusion was found to be extremely low.

In order to analyze the impact of the waste heat utilization environment in phosphate compound fertilizer industrial production on the corrosion behavior of steam turbine rotors, various methods such as the mass loss method, laser scanning confocal microscopy (CLSM), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS) and electrochemical tests were employed. The corrosion behavior and patterns of the steam turbine rotor material, 2Cr-1Ni-1.2Mo-0.2V steel in 120 mmol/L NH4H2PO4 solution at an external temperature of 25 ℃ were investigated. Results showed that 2Cr-1Ni-1.2Mo-0.2V steel underwent uniform corrosion. The corrosion rate first rapidly decreased and then slowly decreased, gradually stabilizing towards 0.2 mm/a. When the NH4H2PO4 concentration was 120 mmol/L and the temperature was 25 ℃, the service life of 2Cr-1Ni-1.2Mo-0.2V steel was determined to be 7.5 a. The corrosion product film of 2Cr-1Ni-1.2Mo-0.2V steel in NH4H2PO4 solution was composed of Fe3(PO4)2, FePO4, Fe(OH)3, FeOOH, and Fe3O4. As the immersion time prolonged, the coverage, compactness and thickness of the corrosion product film were observed to increase, and Cr was found to be enriched in the corrosion product film, thereby enhancing the corrosion resistance of 2Cr-1Ni-1.2Mo-0.2V steel.

Objective: This study aimed to develop konjac rice noodles products with low glycemic index. Methods: The fresh wet rice noodles was made by adding 20%, 10% and 5% konjac refined flour into rice noodles, respectively. The effects of the addition of konjac refined flour on the texture, cooking performance, and sensory quality of rice noodles were studied by texture analyzer and rapid viscosity analyzer. The starch hydrolysis rate, digestion rate, and glycemic index of konjac rice noodles were studied by in vitro digestion model. Results: The cooking loss rate and turbidity of 5% konjac rice noodles were significantly reduced, and there was no significant difference in sensory scores between them and white rice noodles. Compared with white rice noodles with a high estimated glycemic index, the estimated glycemic index of rice noodles with 5% konjac flour significantly decreased to 60.49, and it has a higher nutritional value. Conclusion: The konjac rice noodles product with 5% konjac refined flour can significantly reduce the glycemic index of rice noodles, and its edible quality is as same as the traditional white rice flour products.

Being nutritious, aquatic products are loved by consumers. However, aquatic products are prone to bacterial spoilage, posing safety risks to consumers. The current research proves that bacterial spoilage capacity and virulence are often regulated by its quorum sensing (QS) system, so using quorum sensing inhibitors (QSIs) to intervene in the QS system is an effective way to control bacteria. Currently, more and more QSIs have been discovered from microorganisms, plants and animals. Along with the development of biological engineering, cheminformatics and nanotechnology, artificial QSIs have been synthesized. In order to provide a reference for quality and safety control of aquatic products based on QS inhibition, this article reviews the QS systems of seveal common aquatic product-borne pathogenic and spoilage bacteria and the modes of regulatory effects of the QS systems on virulence factors, with a focus on the current status of research on microbial-, plant-, animal-derived and synthetic QSIs.

The intensifying exploration for deep-buried oil and gas reserves in the southwestern Tarim Basin accelerates the necessity to understand how the structure and evolution of the Precambrian basement affect the development and distribution of Precambrian strata. However, the lack of systematic and comprehensive understanding of the structural characteristics of the Precambrian basement in the southwestern Tarim Basin restricts further advancements in the exploration of ultra-deep oil and gas reserves in this area. Based on the previous research results, this study analyzed the lithology, age, structure, and evolution of the Precambrian basement in the southwestern Tarim Basin by utilizing integrated research methods of geology and geophysics and in combination with the U-Pb dating results of the Precambrian basement. The results reveal that the structure of the Precambrian basement in the Bachu uplift region is characterized by Paleozoic strata overlying directly on the Paleo-proterozoic metamorphic rocks/granites. In the Maigaiti slope and southwestern depression, it exhibits a typical three-tier structure: the Paleoproterozoic metamorphic rocks/granites at the bottom, overlain by sedimentary build-ups from the rifting to depression evolution of the Nanhua-Sinian system. Evolution of the Precambrian basement in the southwestern Tarim Basin was primarily transpired in five phases: continental rifting in the Columbia supercontinent (> 1.1 Ga), assembly of the southwestern Tarim block and the Australian plate (about 1.0 Ga), assemblage between the northern and southern Tarim blocks (900-800 Ma), Nanhua rifting period (760-640 Ma), and Sinian depression period (< 635 Ma). The uplift and downwarping structures during the Nanhua rifting period dictated the development of the Sinian-Lower Cambrian sedimentary strata. In-depth research into the structure and evolution of the Precambrian basement in the southwestern Tarim Basin, as presented in this study, provides important theoretical basis for deep oil and gas exploration in the region, and helps to promote further development of ultra-deep oil and gas exploration.

Per- and poly-fluoroalkyl substances (PFAS) are a new type of persistent organic pollutants that have received extensive attention in recent years. This article reviewed the population characteristics of environmental exposure to PFAS, as well as the potential health effects. Previous studies have verified that people are exposed to PFAS mainly through ingestion, and food and water are the dominant contributors. In terms of exposure characteristics, geographical, gender, age, and occupational differences have an impact on the level of PFAS exposure in the corresponding populations by influencing their behavioral characteristics and metabolic levels, with occupational exposure receiving more attention, especially in the exploration of novel PFAS. PFAS associate with a variety of adverse health effects caused by hepatorenal toxicity, immunotoxicity, reproductive toxicity, neurotoxicity, and carcinogenicity. However, some of the conclusions are not completely consistent, and the published epidemiological studies have focused on children and young people, lacking relevant data of the elderly. Future research can pay more attention to the elderly population and carry out validation exploration on controversial conclusions.

It is a prerequisite for the success of amphibious operations to grasp the battlefield situation comprehensively and accurately. Firstly, this paper analyzes the demand of situation intelligent cognition in amphibious operations, then proposes the conceptual framework of situation intelligent cognition. Secondly, it describes its function, effect and major models of each component. The research provides guidance for the development of amphibious combat situation awareness ability to intelligent cognitive ability, and promotes the improvement of system combat capability of amphibious operations in the future.

Micro-area electrochemical measurement technique can detect metal galvanic corrosion in situ at the micron or even sub-micron scale, which provides a new way for further study of metal galvanic corrosion. In this paper, the basic principle and main influencing factors of metal galvanic corrosion were introduced. The advantages, disadvantages and application status of commonly used micro-area electrochemical measurement techniques such as wire beam electrode (WBE), localized electrochemical impedance spectroscopy (LEIS), scanning vibrating electrode technique (SVET), scanning electrochemical microscopy (SECM), and scanning Kelvin probe (SKP) were reviewed in metal galvanic corrosion research. Finally, the future development of the micro-area electrochemical measurement technique was prospected.

Metabolic syndrome is a chronic systemic metabolic disorder. The number of patients with this disease is increasing year by year, and its prevalence is affected by age, gender, and dietary habits. Studies have pointed out that metabolic syndrome is closely related to insulin resistance, obesity, oxidative stress, and inflammation. In recent years, it has been found that intestinal flora is closely related to metabolic syndrome through omics methods such as macroeconomics and amplicon sequencing. Probiotics, a strategy to regulate intestinal flora, can improve oxidative stress, reduce the secretion of pro-inflammatory factors, and regulate glucose and lipid metabolism by regulating intestinal flora and its metabolites, thereby alleviating metabolic syndrome. This article systematically summarizes the pathological mechanism of metabolic syndrome and the relationship between intestinal flora and metabolic syndrome, and expounds the key molecular targets and specific signaling pathways by which probiotics mitigate metabolic syndrome. This review hopes to provide a theoretical reference for the development of probiotics as a new strategy for the treatment of metabolic syndrome and the targeted mining of healthy and functional microorganisms with the ability to improve metabolic syndrome.

Objective In an effort to prevent transfusion-transmitted hepatitis B infection, universal HBsAg screening, HBsAg+ MP nucleic acid test(NAT) for HBV and HBsAg + individual(ID) NAT were analyzed for cost-effectiveness. Methods On the basis of screening data and the documented parameter, the number of window period infections, chronic infections and occult infections was constructed, and cost-benefit analysis was conducted. Results Of 132 208 donations, the yield rate of ID NAT for HBsAg-/DNA+ (0.11%) was significantly higher than HBsAg+ MP NAT(0.058%). Furthermore, the predicted preventing transfusion transmitted HBV cases by ID NAT is 1.25 times as that by MP-6 NAT, so did the benefits. The cost-benefit of the three screening models were 1∶63.6、1∶28.6 and 1∶53.4. Conclusion Universal HBsAg in combination with ID HBV NAT screening was the most effective among all screening strategy. It is necessary to applied HBsAg and ID HBV NAT screening for the safety of blood transfusion.

Magnesium alloy is a light-weight structural material.Applying this material in vehicles can reduce the vehicles’overall mass and energy consumption and improve their mobility and endurance.However,magnesium alloys are prone to corrosion,and their corrosion resistance needs to be enhanced.The surface diffusion method is a common surface strengthening method for magnesium alloys,in which the metal elements in the diffusion agent are transported to the surface of the magnesium alloy at a certain temperature and finally form a protective layer.Firstly,several common methods of surface diffusion on magnesium alloys were introduced in this paper.Secondly,the main influencing factors of thermal diffusion on the surface of magnesium alloys were summarized.Finally,the performance of the diffusion layer prepared by this method was introduced.The thickness of a typical diffusion layer formed by thermal diffusion on the surface of magnesium alloy could reach hundreds of microns,and the hardness and corrosion resistance of the diffusion layer were significantly improved compared with those of the substrate.Overall,surface thermal diffustion could effectively strengthen the surface of magnesium alloys.

This paper centers on the core business application—the automatic topology identification in transformer areas—of distribution IoT with new energy as its mainstay. It proposes an automatic topology identification technology testing scheme that considers identification reliability， high identification accuracy， and anti-disturbance capability. Besides， a unique “edge-to-end” interaction test platform for the distribution IoT area is developed. Afterward， the functions and performance of the mainstream technical schemes of Zhejiang Electric Power Co.， Ltd. are evaluated in all aspects. The “active current injection plus frequency-domain signal detection” is selected as the optimal technical scheme for topology identification. The topology identification technology testing and research can lay the application foundation for the subsequent interconnection， intercommunication， and interoperability of the distribution IoT and the transformation of the distribution networks.

Objective To analyze the cost-effectiveness of ELISA grey area strategy through establishing the health economics model. Methods The serological grey area strategy evaluation model was composed of screening strategy subdecision tree, pathogen infection subdecision tree and pathogen detection subdecision tree. The key parameters in the model were obtained from literatures and research data. The cost-effectiveness of setting ELISA grey area strategy was compared by software, and multifactor sensitivity analysis was conducted. Results After setting the ELISA grey area, extra samples(5.86 cases/100 000) with serological false negativity could be detected, including HBV samples at 4.93/100 000, HCV samples at 0.27/100 000, HIV samples at 0/100 000, syphilis samples at 0.66/100 000. To yield an additional seropositive sample out of every 100 000 blood donors, blood center will afford extra 1 million yuan about. Conclusion Through this study, a cost-effectiveness evaluation model of serological detection strategy was established. Although the ELISA grey area setting can yield a small number of seropositive samples, the cost is much higher than the current affordability.

Objective To summarize the experience and effect using 3D parametric surface planar topological guide plate technology in fenestrated/branched endovascular aortic repair (F/B EVAR) to repair aortic arch and thoracoabdominal aortic lesions involving important aortic branches. Methods From August 2020 through April 2022, 17 patients [14 males and 3 females, mean age of(61.06±11.23)(39-78) years] with complex aortic lesions involving important branches were treated in both Nanjing Drum Tower Hospital and Union Hospital. There were 8 cases with aortic arch aneurysms 4 cases and dissections 4 cases, respectively, and 9 cases with thoracoabdominal aortic aneurysms 5 cases and dissections 4 cases, respectively. Six cases were urgent operation and 11 cases were selective operation. Before operation, 3D parametric surface planar topological guide plate was made according to aortic computed tomography angiography. Under the guidance of planar guide plate, pre-fenestrated and external/internal branched and other endovascular aortic repair was performed. Totally, 50 fenestrated/branched stent grafts were planted. Results All operations were completed without conversion to open surgery. Average operative time was (4.57±2.29)(1.50-10.67) h. There was no renal insufficiency, paraplegia and loss of branch arteries. One patient (5.88%) died during perioperative period. Within the follow-up, there were 2 cases (11.76%) of endoleak type Ⅰc and type Ⅲc, respectively. Conclusions F/B EVAR under the guidance of 3D parametric surface planar topological guide plate is a minimally invasive treatment. The technology is more accurate than traditional measurement and positioning, faster than 3D printing guidance, and safe and reliable shown in the follow-up.

Pickle is a traditional Fermented food in China, which has a history of thousands of years. Pickles have attracted wide attention as a health food in the world because of their unique flavor, quality and probiotics. In recent years, as the next generation of high-throughput sequencing technologies, the third generation sequencing technology, acer genomics and transcriptome study etc are widely used in the study of molecular biology technology in fermented food. Researches on the microbial community diversity and function mechanism in the pickles have made significant progress, however, the relevant generalizations are not comprehensive enough. Therefore, this paper focuses on the relationship between microorganisms in pickles and the formation of flavor substances in recent years, the formation mechanism of flavor substances, summarizes the control and utilization of microorganisms in pickles and other aspects of the latest research progress, and describes the diversity and probiotics of microorganisms in pickles. It is expected to provide reference for further study on the formation mechanism of the flavor substances of pickles, improve the flavor quality of pickles, and realize the modern processing of traditional pickles.

Objective To establish a routine screening method for unexpected antibodies of blood donors, analyze the results of centralized screening for unexpected antibody of blood donors in the blood center, and compare the cost of centralized and decentralized screening modes. Methods A total of 35 591 blood donors were screened for unexpected antibodies from March 31, 2021 to July 31, 2021, using microcolumn gel method. Unexpected antibody screening reactive samples were further confirmed by the Transfusion Research Institute of Shenzhen Blood Center, and the demographic characteristics were further determined through the analysis of unexpected antibody positive population. The direct cost and indirect cost of centralized and decentralized unexpected antibody screening mode were compared. Results Forty unexpected antibody positive samples were confirmed in Shenzhen, with the positive rate at 0.11%(40/35 591), among which MNS, Rh and Lewis system accounted for 35% (14/40), 32.5% (13/40) and 17.5% (7/40), respectively. Males and females accounted for 45% (18/40) and 55% (22/40), respectively (P0.05). Unexpected antibody screening in a centralized way saved about 1.16 million yuan per year. Conclusion It is necessary to carry out unexpected antibody screening for all blood donors, and centralized screening is more economical than decentralized screening.

Objective To assess three severe acute respiratorysyndrome coronavirus 2 (SARS-CoV-2) enzyme linked immunosorbent assays (ELISA) and one pseudotype lentivirus-based neutralization test (ppNAT) in detecting the convalescent plasma antibody levles from COVID-19. Methods 30 COVID-19 convalescent plasma samples were screened for antibodies against SARS-CoV-2 using three kinds of SARS-CoV-2 ELISA reagents and one ppNAT test in Shenzhen. The controls consisted of plasma samples from 32 healthy blood donors in February 2019. The diagnostic efficacy analysis of various SARS-CoV-2 ELISA reagents was performed using real-time fluorescent Polymerase Chain Reaction (RT-PCR). We also analyzed correlation between different immunological reagents and the age, gender, hospitalization, and severity of illness. Results The positive yielding rate of ppNAT and three kinds of IgG ELISA was higher than that of IgM ELISA. The positive yielding rates of three kinds of IgG ELISA were 100%(30/30), 93.33%(28/30), and 96.67%(29/30) respectively, while the yielding rates in control group were all 0. The positive yielding rate of three IgM ELISAs were 93.33%(28/30), 70%(21/30)and 46.67% (14/30). All the cases from negative control group were negative for IgG and IgM. Pearson correlation coefficient was calculated; there was a strong correlation between ELISA reagent 2 IgG and ELISA reagent 3 IgG (r=0.765, P0.05). Conclusion In the convalescent plasma with nucleic acid confirmed covid-19, the yielding rates of different IgM antibodies varied greatly. Antibody levels were influenced by age to some extent.

Objective To evaluate the performance and clinical application of a high-throughput nucleic acid blood screening detection system for SARS-CoV-2, so as to provide basis and technical means for its application in detection of plasma from recovered COVID-19 patients. Methods The SARS-CoV-2 nucleic acid was detected by real-time fluorescence quantitative PCR, and the sensitivity, precision, anti-interference and other parameters were evaluated. Blood donor samples collected during COVID-19 epidemic period were screened using the detection system to evaluate its applicability. Results The detection limits of gene N and ORF 1ab were 3.98 copies/mL and 9.38 copies/mL, respectively. The CV of high and low concentration samples were both less than 5%. Hemoglobin at 500 mg/dL and triglyceride at 3g/dL had little effect on the results. The detection system can effectively prevent carryover, thus avoiding false positive results. The SARS-CoV-2 nucleic acid blood screening was carried out in a total of 39 306 blood samples, and all samples were negative. Conclusion The established method can meet the needs of SARS-CoV-2 nucleic acid screening therefore ensure the safe application of plasma from recovered COVID-19 patients.

In order to clarify the quality change of indica-japonica hybrid rice in different packaging，this experiment was conducted to study the effects of four packaging, woven bags, PE bags, vacuum packages and kraft paper bags, on the rice and steamed rice quality at room temperature (20~25 ℃) with YongYu 15 rice as raw material. The results showed that, with the extension of storage time, the fatty acid value, amylose content and rice hardness of indica japonica hybrid rice increased gradually, while the indexes of rice freshness value, taste value, viscosity and taste value of rice decreased gradually. The correlation between the quality indexes was significant (P PE bag > woven bag > kraft paper bag. The above results show that, the vacuum and barrier packaging could effectively delay the decrease of the quality of indica-japonica hybrid rice and its cooked rice, and improve its storage quality.

Objective: To investigate the effects of conjugated linoleic acid (CLA) on lipid accumulation and intestinal microbiota in obese rats. Methods: Forty SPF male SD rats were randomly divided into four groups according to body weight, 10 rats in each group. The ND group was fed with ordinary diet, and the other groups were fed with high-fat diet. Among them, the ND group was intragastrically administered with peanut oil 1 g/kg, the model group (HD group) was intragastrically administered with peanut oil 1 g/kg, the low-dose group (LC group) was intragastrically administered with 0.2% conjugated linoleic acid 1 g/kg, and the high-dose group (HC group) was intragastrically administered with 2% conjugated linoleic acid 1 g/kg for 9 weeks of intervention. Bacterial DNA was extracted from feces of mice after collection of feces at the end of the experiment followed by 16S rDNA sequencing, after which blood was collected and sacrificed under anesthesia, and organ and visceral fat were taken and stored at −80 ℃. Results: The body weight, visceral fat, serum and liver triglycerides and total cholesterol of rats in the HD group were significantly higher than those in the ND group (P

Spatial distance join is one of the most common operations for spatial data analysis,which has various application scenarios.Existing distributed methods face the problems of too large space,high data skew,and slow self-join.To this end,this paper proposes a novel distributed distance join algorithm,i.e.,JUST-Join,for massive spatial data.First,JUST-Join regards only the necessary space as the global domain,which can filter invalid data out,reducing the overhead of unnecessary data transmission and computation.Second,we consider both the spatial distributions of the two datasets,which relieves the data skew issue.Third,for the spatial self-join,we adopt plane sweep method to further improve the efficiency.We implement JUST-Join algorithm based on Spark,and conduct extensive experiments using real datasets.The experimental results show that JUST-Join is superior to the state-of-the-art distributed spatial analysis systems in terms both of efficiency and scalability.

The topological structure and line impedance parameters of low-and medium-voltage distribution networks are the foundation of realizing various functions of the future intelligent distribution networks. Given the shortcomings of traditional distribution network topology identification methods such as poor timeliness and inability to accurately obtain line impedance parameters， a topology identification and line impedance estimation method for low-and medium-voltage distribution networks driven only by voltage and power data of distribution network nodes is proposed with the backing of power information provided by AMI （advanced metering infrastructure）. Firstly， the kernel density estimation method is used to calculate the mutual information （MI） among node voltage data and analyze the correlation among nodes accordingly. Secondly， the distribution network topology is generated in the form of an adjacency matrix according to the minimum spanning tree algorithm. Thirdly， the topology is corrected by combining linear regression and Distflow model to check whether there are outflow nodes without relevant data in the AMI system， and the line impedance is calculated. Finally， the accurate distribution network topology and line impedance parameters are obtained. The proposed method is validated by using examples of IEEE 33-node medium-voltage distribution networks and typical low-voltage distribution networks. The results show that the proposed method can accurately identify the topology and line impedance parameters even in the absence of sensing equipment for low-voltage distribution networks.

To improve the accuracy of photovoltaic (PV) power prediction, this paper proposes a novel weather classification method. First, it distinguishs the clear days and cloudy days according to the total cloud cover. Then, it further classifies the cloudy days into three subtypes to investigate whether the sun is obscured by clouds. This method can effectively identify the characteristics of key meteorological environmental factors that affect PV output and form a new classification index sky condition factor (SCF) by weighted summation. This method has clear physical meanings, good discrimination, and easy quantification. The reasonable classification of weather types can eliminate the coupling relationship between many meteorological environmental factors and reduce the dimension of input variables, which makes it easy for statistical modeling. Based on the theoretical and the statistical approachs respectively, the modeling and verification are conducted and the results show that the method can effectively improve the accuracy of PV power prediction.

As the optical network structure becomes larger and more complex, optical network faults are more likely to occur. After a network fault occurs, due to the derivative characteristics of network alarms, the root cause alarms will generate multiple derivative alarms. Therefore, after network faults occur, the network management system will receive alarm storms. Due to the complex relationship between faults and alarms, the difficulty of locating network faults, especially multiple faults, has also risen sharply. In response to this problem, the knowledge graph technology that is good at managing massive amounts of information and revealing the characteristics of data is introduced into optical networks. The alarm knowledge graph contains rich relationships between alarms, which can be completed by combining Graph Neural Network (GNN) technology. The knowledge-guided automatic reasoning of the root cause of network faults is in line with the fault location ideas of the operation and maintenance personnel in the operation and maintenance process. Further, the network topology information is added in the fault location process, and the knowledge dimension of the knowledge graph is improved. The limitation of the single-fault scenario is lifted, and a high accuracy rate is obtained in the multi-fault location scenario.

Recently, reconfigurable metasurfaces have attracted intense attention in the field of electromagnetic metasurfaces. Compared with other metasurfaces, reconfigurable metasurfaces that uses steerable devices or materials to control the electromagnetic wave in real time are more versatile and show great promise in engineering applications. Our team has continuously explored advances of reconfigurable metasurfaces and also studied the microwave region from the perspectives of theory, technique and applications. This study reviews the research history of reconfigurable metasurfaces and summarizes some of our previous works, including a study on the amplitude, phase and polarization modulation of electromagnetic waves and their applications. Finally, the study discusses future challenges and possibilities for reconfigurable metasurfaces.

Venous thromboembolism (VTE) is a preventable perioperative complication of malignant tumor in thoracic surgery. At present, low molecular weight heparin anticoagulants are the first choices for perioperative drug prevention of malignant tumors, and direct oral anticoagulants are not recommended for perioperative use of malignant tumors in thoracic surgery, but their application in other related fields is relatively mature. This article will introduce direct oral anticoagulants and analyze the prospect of their perioperative application in patients with thoracic malignant tumors. It is helpful to better understand the relevant contents of "perioperative VTE prophylaxis in thoracic cancer patients: Chinese experts consensus (2018 edition)".

doi：10.3969/j.issn.1672⁃6731.2021.02.010

Squamous cell lung cancer (SqCLC) is a unique clinical and histologic category of non-small cell lung cancer (NSCLC). Most of patients with SqCLC tend to be older, typically at advanced stage, associated with smoking and have more complications. With progress of targeted therapy of lung cancer, we identified several potential actionable genetic abnormalities such as FGFR. Several FGFR inhibitors have been approved for clinical use in different cancers. And some of these agents are currently under investigation in clinical trials for SqCLC. This article summarizes the current knowledge about FGFR aberrations, the relative inhibitors in development and clinical data in SqCLC.

Objective To analyse the genetic polymorphisms of 66 biallelic genetic markers on Y chromosome in Eastern Chinese Han population, and evaluate their values in forensic application. Methods Genotyping of 66 biallelic genetic markers on Y chromosome was studied in 205 unrelated males of Eastern Chinese Han population by multiplex PCR combined matrix-assisted laser desorption/ionization time-of-flight mass spectrometry （MALDI-TOF-MS）. The allele frequencies on the loci to be tested were calculated by direct counting method, and the gene diversity （GD） and haplotype diversity （HD） were calculated by corresponding formulas. The haplotypes of this system were tested by software Arlequin v3.5.2.2 and the comparison of population genetics were analyzed. Results A total of 60 biallelic genetic markers on Y chromosome were polymorphic in males of Eastern Chinese Han population, and the ranges of GD were from 0.038 5 to 0.501 9. Eighty-five different haplotypes were observed and the HD was 0.970 3. The differences of partial SNP loci between the Han population of Eastern China and that of Xinjiang and Guangdong were statistically significance. Conclusion Sixty biallelic genetic markers and the detection system can complementally provide genetic information in kinship testing and individual identification. The MALDI-TOF-MS technology is able to type biallelic genetic markers.

Objective To study the outcome of the transoral reduction and fixation of basilar invagination and atlantoaxial dislocation, to evaluate this novel technique involving a microscope⁃assisted anterior release and reduction and fixation through a transoral⁃transpharyngeal approach and describe the safety and efficacy of a new minimal invasive technique for the irreducible atlantoaxial dislocation (IADD). Methods A prospective clinical study was performed. Three consecutive irreducible atlantoaxial dislocation patients underwent a microscope ⁃ assisted anterior release and reduction and fixation through transoral⁃transpharyngeal approach. Transoral atlantoaxial reduction plate (TARP) for anterior fixation and autologous morselized bone grafting were used during the operation. The Japanese Orthopaedic Association (JOA) scoring system was used to evaluate each patient's neurological status pre⁃ and post⁃operatively, and serial MRI and radiographs were used to evaluate the status of the reduction including the atlantoaxial interval and cervicomedullary angle were also measured. The clinical features, imaging data, special preoperative preparation, surgical approach, skills and postoperative complications of the 3 cases were analyzed. Results The average operation time was 130 min (110 min, 130 min, 150 min, respectively) and the mean estimated blood loss was 150 ml (100 ml, 200 ml, 150 ml, respectively). According to the postoperative CT all the 3 plates and 12 screws were appropriately placed and fixed. All cases of basilar invagination and atlantoaxial dislocation were corrected differentially in terms of anatomic reduction and neurological disturbances were reversed remarkably. The improvement rate of spinal cord function was 75.00%, 40.00%, 56.25%, respectively according to JOA score, average improvement rate was 57.08%, and average recovery rating was "good". Postoperative nosocomial intracranial infection occurred in one case and was cured finally. Conclusion Microscope⁃assisted transoral⁃transpharyngeal reduction and fixation for the treatment of basilar invagination and atlantoaxial dislocation is feasible and valuable. DOI：10.3969/j.issn.1672⁃6731.2012.04.011

Objective Detecting moving targets in moving camera environments from video stream is a fundamental step in many computer vision applications, such as intelligent visual surveillance, human-machine interaction, and content-based video coding. Background subtraction is generally regarded as an effective method for extracting foreground objects. Given the existence of extensive literature regarding background subtraction, most existing methods assume a stationary camera. This assumption limits the applicability of these methods to moving camera scenarios. Background is a complex environment that usually includes distracting motions, which make the task more challenging. In addition, with the development of coding techniques, high-definition videos have become widely used. Thus, extracting and updating background images become complex and time-consuming processes. To solve this problem, a fast target detection method is proposed on the basis of V motion vectors. Method The data format and decoding features of surveillance videos are analyzed in this study. Subsequently, methods by which to obtain motion vectors directly from a video stream are determined, and results confirm the method validity by comparing the motion vectors extracted through this method with those extracted using the H. 264 Visa business software. Moreover, the motion vectors are normalized by considering the reference frames, thus preventing the emergence of singular motion vectors and making the distribution of the motion vectors more reasonable. Global motion is detected according to 3σ theory, and different compensation algorithms are proposed for various scenarios. Finally, targets are extracted by analyzing the statistical property of motion vectors. Result Detecting moving targets from a moving camera is difficult. For conventional methods, moving background is not always considered, and systems that have a delayed response to background changes are unsuitable for this situation. To meet the real-time performance requirements of the system, motion vectors are used to detect global motion and extract motion targets, thus reducing redundant computation effectively. Test results show that the proposed method is superior to conventional methods. Conclusion To prove the validity of this algorithm, an extensive set of experiments are performed, and the proposed method is compared with some of the most recent approaches in the field by using publicly available datasets and a new annotated dataset. Results prove that the proposed approach can effectively extract high-speed moving targets from a moving camera. [ABSTRACT FROM AUTHOR]

Time delay estimation (TDE) in impulse noise environments is one of the most active subjects in the signal processing field. In the symmetric α-stable distribution noise environments, a new time delay estimation algorithm for HF fading signal based on a nonlinear compress core function (NCCF) is provided. The NCC function is able to not only suppress the pulse stretching of the α-stable distribution noise, but also preserve the cross correlation between the object signals. As a result, it confirms the good performance of the signal time delay estimation algorithm. Comparing with the classical time delay estimation methods, this new method has the advantages in reducing the computational complexity as well as improving the stability of the estimator. Theoretical proof is also provided in this paper to illuminate the features of the algorithm. Simulation results shows that the new algorithm has better accuracy and validity than the GCC, FLOC, GCF and the nonlinear transformation algorithms. [ABSTRACT FROM AUTHOR]

Discussed the origins of coalbed methane in Luling Coal Mine of Huaibei coalfield from the aspects of carbon and hydrogen isotope of methane, the quantitative relationship between δ5D(CH4), δD(H2O) and the source of coalbed produced water. The results reveal that the methane is predominant (up to 97%) and is thought as extremely dry. δ13C(CH4) from -67.6‰ to -64.2‰ and δD(CH4) from -206‰ to -224‰, so it is in the range of biogenic gas. Quantitative relationship between δ D(CH4) and δ D(H2O) indicates that the methane mainly generated by carbon dioxide is biogenic methane. Hydrogen and oxygen of water sample falls near the meteoric water line, indicating they are all from precipitation, so it meets the condition of water supply for generation of biogenic methane. Therefore, integrating the above three aspects of qualitative and quantitative analysis and the history of tectono-thermal, that the extant methane is secondary microbial origin in Luling Coal Mine of Huaibei coalfield is concluded. [ABSTRACT FROM AUTHOR]

Currently, 3D CT images play an important role in the lossless detection of industry, and the focus analysis of medicine are widely used in the industrial and the medicinal field. In order to detect the line targets widely existed in the CT images, traditional methods were Hough transform and Radon transform. However the complexity of them were huge in the 3D space, what's more, they were not applicable by curve targets. So this paper proposed a method based on distance transform and terminal node, turned nodes detection to detect line targets. It was not only suitable to the line, but also to the curve. Furthermore, it could get the thickness of the line targets automatically from the step of distance transform. The result of experiments shows the availability of this method. [ABSTRACT FROM AUTHOR]