Non-uniformity calibration method of space-borne area CCD for directional polarimetric camera.

The directional polarimetric camera (DPC) is a polarization sensor with the characteristics of ultra-wide-angle and low-distortion imaging. The multi-angle polarization information is helpful to obtain the spatial distribution of target radiation, and multiple data fusion relies on the non-uniformity calibration of image plane. The non-uniformity consists of many factors such as lens, detector assembly, spatial stray light, etc. The single correction method can not distinguish the error source effectively. In consideration of the in-flight operation mode of DPC based on the adjustment of exposure time, the non-uniformity correction method of the detector based on multi parameters is proposed. Through the electro-optical performance measurement system of the CCD detector, the sensitive factors such as temperature, dark current, exposure time and spectral response are obtained. After a series of preprocessing of the image including removal of dark signal, removal of smearing effect and temperature compensation, the non-uniformity calibration based on multi-parameters is imposed on the detector. The low-frequency unbalanced response difference of the image surface is eliminated, and the high-frequency difference is effectively suppressed. The experimental results show that the photo response non-uniformity of 95% full well single frame data is reduced from 2.86% to 0.36%. After correction, the data noise is shown as shot noise, and the detector has good ability of dynamic range adjustment. The non-uniformity calibration by the proposed method can offer data support for the instrumental calibration and in-flight fast calculation, and provide effective reference for the subsequent polarization remote sensing instruments.

SnS2 Nanosheets Coating on Nanohollow Cubic CoS2 /C for Ultralong Life and High Rate Capability Half/Full Sodium-Ion Batteries.

Sodium-ion batteries (SIBs) have attracted tremendous interest and become a worldwide research hotpot owing to their low cost and abundant resources. To obtain suitable anode materials with excellent performance for SIBs, an effective and controllable strategy is presented to fabricate SnS2 nanosheets coating on nanohollow cubic CoS2 /C (CoS2 /C@SnS2 ) composites with a hollow structure using Co-metal-organic frameworks as the starting material. As anodes for SIBs, the CoS2 /C@SnS2 electrode exhibits ultralong cycle life and excellent rate performance, which can maintain a high specific capacity of 400.1 mAh g-1 even after 3500 cycles at a current density of 10 A g-1 . When used in a full-cell, it also shows enhanced sodium storage properties and delivers a high reversible capacity of 567.3 mAh g-1 after 1000 cycles at 1 A g-1 . This strategy can pave a way for preparing various metal sulfides with fascinating structure and excellent performance for the potential application in energy storage area.

Comparative Studies on Enzyme Activity of Immobilized Horseradish Peroxidase in Silica Nanomaterials with Three Different Shapes and Methoxychlor Degradation of Vesicle-Like Mesoporous SiO2 as Carrier.

In the present work, three differently shaped mesoporous silica nanoparticles, spherical nano-SiO2, tubular mesoporous SiO2 and vesicle-like mesoporous SiO2 (VSL), were prepared and used to immobilize Horse radish peroxidase (HRP), and their enzyme's activity was also evaluated. It was found that the VSL immobilized HRP displayed higher specific activity than free enzyme and other two differently shaped silica immobilized HRP. After immobilization, the thermal stability, pH tolerance resistance and storage stability on vesicle-like SiO2 were studied as well. In addition, the kinetic constants Km and Vmax for HRP were significantly altered by immobilization. The affinity for HRP towards its substrate increased (with decreasing Km), leading to enhanced catalytic efficiency (with increased Vmax). Moreover, the reusability for degradation of methoxychlor (MXC) by VSL immobilized enzyme was studied and its degradation products were detected by GC-MS and NMR analysis.

Preparation and In Vivo Biodistribution of Ultra-Small Superparamagnetic Iron Oxide Nanoparticles with High Magnetic Targeting Response.

The ultra-small superparamagnetic iron oxide (USPIO) particles with high saturation magnetization and good superparamagnetism were prepared by reverse micro-emulsions using novel C16E15 as surfactant, which can reduce magnetic dipole-dipole interaction, hence decreasing the critical blocking temperature (TB). Powder X-ray diffraction (XRD), Infrared spectrum (FT-IR), Transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and Vibrating sample magnetometer (VSM) were used to characterize the magnetic particles. The higher ratio of Fe2+/Fe3+ caused redundant FeO on the USPIO surface. An in vitro approach model for simulating target delivery of USPIO particles to sites of interest was developed to illustrate the relationship between magnetic fluid retention rate and pole distance. In Vivo targeted interception and magnetic targeting bio-distribution of superparamagnetic particles were also investigated simultaneously. The results indicated that the USPIO had high ability for magnetic focusing in mimetic surrounding tissue surrounding blood vessels under the action of pulsed magnetic field. The USPIO nanoparticles will be fundamental in biomedical applications.

Preparation and Biological Applications of Graphene Oxide Functionalized Water-Based Magnetic Fluids.

Magnetic fluids (MFs) with good dispersion were prepared by speed-controlled co-precipitation method, using polyethylene glycol (PEG-4000) as dispersing agent. To functionalize the MFs with graphene oxide (GO), highly dispersed nano-magnetic particles (NMPs) were firstly prepared by low-temperature freeze-drying technique. 3-aminopropyltriethoxysilane (APTES) was then attached on the surface of NMPs to form amino functionalized NMPs. GO was finally assembled with amino functionalized NMPs, to prepare GO functionalized MFs (GO-NMPs) by electrostatic adsorption. The obtained GO-NMPs were then characterized by FTIR, XRD, TEM, SEM and VSM. Meanwhile, mice were in vivo used as animal model to study biological application of 99Tcm labeled GO-NMPs, suggesting that the targeted functionalized magnetic particles had higher magnetic response effect under pulsed magnetic gradient field.

Genetic Analysis of Neisseria meningitidis Sequence Type 7 Serogroup X Originating from Serogroup A.

Neisseria meningitidis causes meningococcal disease, often resulting in fulminant meningitis, sepsis, and death. Vaccination programs have been developed to prevent infection of this pathogen, but serogroup replacement is a problem. Capsular switching has been an important survival mechanism for N. meningitidis, allowing the organism to evolve in the present vaccine era. However, related mechanisms have not been completely elucidated. Genetic analysis of capsular switching between diverse serogroups would help further our understanding of this pathogen. In this study, we analyzed the genetic characteristics of the sequence type 7 (ST-7) serogroup X strain that was predicted to arise from ST-7 serogroup A at the genomic level. By comparing the genomic structures and sequences, ST-7 serogroup X was closest to ST-7 serogroup A, whereas eight probable recombination regions, including the capsular gene locus, were identified. This indicated that serogroup X originated from serogroup A by recombination leading to capsular switching. The recombination involved approximately 8,540 bp from the end of the ctrC gene to the middle of the galE gene. There were more recombination regions and strain-specific single-nucleotide polymorphisms in serogroup X than in serogroup A genomes. However, no specific gene was found for each serogroup except those in the capsule gene locus.

Prevalence of asymptomatic Bordetella pertussis and Bordetella parapertussis infections among school children in China as determined by pooled real-time PCR: a cross-sectional study.

BACKGROUND: Studies have documented that older children and adolescents act as a reservoir of Bordetella pertussis infection for young infants who have not yet completed their primary immunization schedule. Asymptomatic pertussis infection has been reported during outbreaks. This cross-sectional study aimed to investigate whether B. pertussis and Bordetella parapertussis can colonize the nasopharynx of healthy school children, using culture and pooled real-time PCR with targets for insertion sequences IS481 and IS1001. METHODS: Nasopharyngeal (NP) swabs were taken from 629 asymptomatic school children aged 7 to 15 y in 4 counties of China during the period July-September 2011. The number of subjects included in each county ranged from 153 to 165. The 4 counties selected are located in the north, south, east, and southwest regions of China. NP swabs were inoculated onto Regan-Lowe agar for isolation of suspected Bordetella organisms. Pooled real-time PCRs were used to detect B. pertussis and B. parapertussis based on the IS481 and IS1001 targets separately. RESULTS: Of the 629 subjects, 2 (0.3%) and 30 (4.8%) were confirmed to be culture-positive and PCR-positive, respectively, for B. pertussis, and 1 (0.2%) and 13 (2.1%) were confirmed to be culture-positive and PCR-positive, respectively, for B. parapertussis. All culture-positive samples were also PCR-positive. Furthermore, positive B. pertussis and B. parapertussis samples were found in all counties. CONCLUSIONS: Our results indicate that asymptomatic B. pertussis infections are common in school children in China, and asymptomatic B. parapertussis infections are more prevalent than previously documented.

Research Progress on Surface Damage and Protection Strategies of Armature-Rail Friction Pair Materials for Electromagnetic Rail Launch.

Electromagnetic rail launch technology has attracted increasing attention owing to its advantages in terms of range, firepower, and speed. However, due to electricity-magnetism-heat-force coupling, the surface of the armature-rail friction pair becomes severely damaged, which restricts the development of this technology. A series of studies have been conducted to reduce the damage of the armature-rail friction pair, including an analysis of the damage mechanism and protection strategies. In this study, various types of surface damage were classified into mechanical, electrical, and coupling damages according to their causes. This damage is caused by factors such as mechanical friction, mechanical impact, and electric erosion, either individually or in combination. Then, a detailed investigation of protection strategies for reducing damage is introduced, including material improvement through the use of novel combined deformation and heat treatment processes to achieve high strength and high conductivity, as well as surface treatment technologies such as structural coatings for wear resistance and functional coatings for ablation and melting resistance. Finally, future development prospects of armature-rail friction pair materials are discussed. This study provides a theoretical basis and directions for the development of high-performance materials for the armature-rail friction pair.

Development of an RBD-Fc fusion vaccine for COVID-19.

Although the global pandemic of SARS-CoV-2 has passed, there are still regional outbreaks that continue to jeopardize human health. Hence, there is still a great deal of interest in developing an efficient vaccine that can quickly and effectively prevent reemerging outbreaks of SARS-CoV-2. Delta variant was once a dominant strain in the world in 2021, and we first constructed a recombinant RBDdelta-Fc fusion vaccine by coupling the RBD of Delta variant with the human Fc fragment. This Fc fusion strategy increases the immunogenicity of the recombinant RBD vaccine, with a long-lasting high level of IgG antibodies and neutralizing antibodies induced by RBDdelta-Fc vaccine. This RBDdelta-Fc vaccine, as well as the RBD-Fc vaccine prepared in our previously study, could trigger a durable immune effect by the heterologous boosting immunity, and the RBD-Fc induced a quicker humoral immune response than the homologous immunization with inactivated vaccines. In conclusion, the Fc fusion strategy has a significant role in enhancing the immunogenicity of recombinant protein vaccines, thus promising the development of a safe and efficient vaccine for the heterologous boosting against SARS-CoV-2.

Ozone-Induced Rapid and Green Synthesis of Polydopamine Coatings with High Uniformity and Enhanced Stability.

The development of green, controllable, and simplified pathways for rapid dopamine polymerization holds significant importance in the field of polydopamine (PDA) surface chemistry. In this study, a green strategy is successfully devised to accelerate and control the polymerization of dopamine through the introduction of ozone (O3 ). The findings reveal that ozone serves as an eco-friendly trigger, significantly accelerating the dopamine polymerization process across a broad pH range, spanning from 4.0 to 10.0. Notably, the deposition rate of PDA coatings on a silicon wafer reaches an impressive value of ≈64.8 nm h-1 (pH 8.5), which is 30 times higher than that of traditional air-assisted PDA and comparable to the fastest reported method. Furthermore, ozone exhibits the ability to accelerate dopamine polymerization even under low temperatures. It also enables control over the inhibition-initiation of the polymerization process by regulating the "ON/OFF" mode of the ozone gas. Moreover, the ozone-induced PDA coatings demonstrate exceptional characteristics, including high homogeneity, good hydrophilicity, and remarkable chemical and mechanical stability. Additionally, the ozone-induced PDA coatings can be rapidly and effectively deposited onto a wide range of substrates, particularly those that are adhesion-resistant, such as polytetrafluoroethylene (PTFE).

[Sequence-based typing for 61 Legionella pneumophila serogroup 1 isolates in Zhejiang Province].

OBJECTIVE: To analyze the sequence characteristics of the serogroup 1 Legionella pneumophila (Lp1) strains isolated from the cooling tower water in Zhejiang province by sequence-based typing (SBT). METHODS: 61 strains of Lp1 isolated from cooling tower water in ten cities of Zhejiang Province from 2005 to 2011 were genotyped by SBT method. The nucleotide polymorphism of the sequencing results was analyzed by DnaSP 5.0, and the SBT results were cluster analyzed using SplitsTree and eBURST software. RESULTS: All 61 isolates of Lp1 were resolved into 11 STs, and 5 new STs were found in this study. The ST with the largest number of isolates was ST1 (n=50), and these ST-1 strains were found in 10 cities. The nucleotide polymorphism (Pi) of these seven housekeeping genes ranged from 0.01095 (mip) to 0.05355 (pilE). The STs of the Lpl isolates were clustered to four clonal complexes (CC), and ST-1, ST-149, ST-154 were the three main clonal complexes (CC). CONCLUSION: Genetic diversity was shown in the serogroup 1 Legionella pneumophila strains isolated from cooling tower water in Zhejiang province.

Workplace violence against nursing interns and patient safety: The multiple mediation effect of professional identity and professional burnout.

BACKGROUND: Most nursing interns have suffered some form of workplace violence in clinical settings, which has been linked to the jeopardizing of patient safety. Although previous research studies have examined the effect of workplace violence on patient safety, few studies have examined whether workplace violence is associated with patient safety through professional identity and professional burnout among nursing interns. AIMS: To test whether professional identity and professional burnout play mediating roles in the relationship of workplace violence and patient safety among nursing interns. DESIGN: Cross-sectional study. METHODS: The study included 466 nursing interns from three tertiary grade A hospitals. The Workplace Violence Scale, the Professional Identity Scale, the Maslach Burnout Inventory-General Survey, and the Patient Safety Behaviour Scale were used to gather data. Associations among workplace violence, professional identity, professional burnout, and patient safety were assessed by correlation and the serial-multiple mediation analysis. RESULTS: Workplace violence, professional identity, professional burnout and patient safety were significantly correlated. Workplace violence can have a direct positive impact on patient safety of nursing interns, but also an indirect impact on patient safety through three paths: the independent mediating role of professional identity, the independent mediating role of professional burnout, and the chain mediating role of professional identity and professional burnout. CONCLUSIONS: Our findings suggest that workplace violence can affect patient safety through decreasing professional identity and increasing professional burnout among nursing interns. Interventions aimed at decreasing workplace violence among nursing interns would be beneficial for professional attitude and patient safety.

SARS-CoV-2 N Protein Triggers Acute Lung Injury via Modulating Macrophage Activation and Infiltration in in vitro and in vivo.

Background: SARS-CoV-2-induced acute lung injury but its nucleocapsid (N) and/or Spike (S) protein involvements in the disease pathology remain elusive. Methods: In vitro, the cultured THP-1 macrophages were stimulated with alive SARS-CoV-2 virus at different loading dose, N protein or S protein with/without TICAM2-siRNA, TIRAP-siRNA or MyD88-siRNA. The TICAM2, TIRAP and MyD88 expression in the THP-1 cells after N protein stimulation were determined. In vivo, naïve mice or mice with depletion macrophages were injected with N protein or dead SARS-CoV-2. The macrophages in the lung were analyzed with flow cytometry, and lung sections were stained with H&E or immunohistochemistry. Culture supernatants and serum were harvested for cytokines measurements with cytometric bead array. Results: Alive SARS-CoV-2 virus or N protein but not S protein induced high cytokine releases from macrophages in a time or virus loading dependent manner. MyD88 and TIRAP but not TICAM2 were highly involved in macrophage activation triggered by N protein whilst both inhibited with siRNA decreased inflammatory responses. Moreover, N protein and dead SARS-CoV-2 caused systemic inflammation, macrophage accumulation and acute lung injury in mice. Macrophage depletion in mice decreased cytokines in response to N protein. Conclusion: SARS-CoV-2 and its N protein but not S protein induced acute lung injury and systemic inflammation, which was closely related to macrophage activation, infiltration and release cytokines.

Microstructure and Tensile Properties of Melt-Spun Filaments of Polybutene-1 and Butene-1/Ethylene Copolymer.

Polybutene-1 with form I crystals exhibits excellent creep resistance and environmental stress crack resistance. The filaments of polybutene-1 and its random copolymer with 4 mol% ethylene co-units were produced via extrusion melt spinning, which are expected to be in form I states and show outstanding mechanical properties. The variances in microstructure, crystallization-melting behavior, and mechanical properties between homopolymer and copolymer filaments were analyzed using SEM, SAXS/WAXD, DSC, and tensile tests. The crystallization of form II and subsequent phase transition into form I finished after the melt-spinning process in the copolymer sample while small amounts of form II crystals remained in homopolymer filaments. Surprisingly, copolymer filaments exhibited higher tensile strength and Young's modulus than homopolymer filaments, while the homopolymer films showed better mechanical properties than copolymer films. The high degree of orientation and long fibrous crystals play a critical role in the superior properties of copolymer filaments. The results indicate that the existence of ethylene increases the chain flexibility and benefits the formation of intercrystalline links during spinning, which contributes to an enhancement of mechanical properties. The structure-property correlation of melt-spun PB-1 filaments provides a reference for the development of polymer fibers with excellent creep resistance.

Identification of ADAM23 as a Potential Signature for Psoriasis Using Integrative Machine-Learning and Experimental Verification.

Background: Psoriasis is a common chronic, recurrent, and inflammatory skin disease. Identifying novel and potential biomarkers is valuable in the treatment and diagnosis of psoriasis. The goal of this study was to identify novel key biomarkers of psoriasis and analyze the potential underlying mechanisms. Methods: Psoriasis-related datasets were downloaded from the Gene Expression Omnibus database to screen differential genes in the datasets. Functional and pathway enrichment analyses were performed on the differentially expressed genes (DEGs). Candidate biomarkers for psoriasis were identified from the GSE30999 and GSE6710 datasets using four machine learning algorithms, namely, random forest (RF), least absolute shrinkage and selection operator (LASSO) logistic regression, weighted gene co-expression network analysis (WGCNA), and support vector machine recursive feature elimination (SVM-RFE), and were validated using the GSE41662 dataset. Next, we used CIBERSORT and single-cell RNA analysis to explore the relationship between ADAM23 and immune cells. Finally, we validated the expression of the identified biomarkers expressions in human and mouse experiments. Results: A total of 709 overlapping DEGs were identified, including 426 upregulated and 283 downregulated genes. Enhanced by enrichment analysis, the differentially expressed genes (DEGs) were spatially arranged in relation to immune cell involvement, immune-activating processes, and inflammatory signals. Based on the enrichment analysis, the DEGs were mapped to immune cell involvement, immune-activating processes, and inflammatory signals. Four machine learning strategies and single-cell RNA sequencing analysis showed that ADAM23, a disintegrin and metalloprotease, may be a unique, critical biomarker with high diagnostic accuracy for psoriasis. Based on CIBERSORT analysis, ADAM23 was found to be associated with a variety of immune cells, such as macrophages and mast cells, and it was upregulated in the macrophages of psoriatic lesions in patients and mice. Conclusion: ADAM23 may be a potential biomarker in the diagnosis of psoriasis and may contribute to the pathogenesis by regulating immunological activity in psoriatic lesions.

Hybrid Crosslinked Solid Polymer Electrolyte via In-Situ Solidification Enables High-Performance Solid-State Lithium Metal Batteries.

Solid-state lithium-metal batteries constructed by in-situ solidification of cyclic ether are considered to be a critical strategy for the next generation of solid-state batteries with high energy density and safety. However, the poor thermal/electrochemical stability of linear polyethers and severe interfacial reactions limit its further development. Herein, in-situ ring-opening hybrid crosslinked polymerization is proposed for organic/inorganic hybrid polymer electrolyte (HCPE) with superior ionic conductivity of 2.22 × 10-3 S cm-1 at 30 °C, ultrahigh Li+ transference number of 0.88, and wide electrochemical stability window of 5.2 V. These allow highly stable lithium stripping/plating cycling for over 1000 h at 1 mA cm-2 , which also reveal a well-defined interfacial stabilization mechanism. Thus, HCPE endows assembled solid-state lithium-metal batteries with excellent long-cycle performance over 600 cycles at 2 C (25 °C) and superior capacity retention of 92.1%. More importantly, the proposed noncombustible HCPE opens up a new frontier to promote the practical application of high safety and high energy density solid-state batteries via in-situ solidification.

Allelic imbalance of HLA-B expression in human lung cells infected with coronavirus and other respiratory viruses.

The human leucocyte antigen (HLA) loci have been widely characterized to be associated with viral infectious diseases using either HLA allele frequency-based association or in silico predicted studies. However, there is less experimental evidence to link the HLA alleles with COVID-19 and other respiratory infectious diseases, particularly in the lung cells. To examine the role of HLA alleles in response to coronavirus and other respiratory viral infections in disease-relevant cells, we designed a two-stage study by integrating publicly accessible RNA-seq data sets, and performed allelic expression (AE) analysis on heterozygous HLA genotypes. We discovered an increased AE pattern accompanied with overexpression of HLA-B gene in SARS-CoV-2-infected human lung epithelial cells. Analysis of independent data sets verified the respiratory virus-induced AE of HLA-B gene in lung cells and tissues. The results were further experimentally validated in cultured lung cells infected with SARS-CoV-2. We further uncovered that the antiviral cytokine IFNß contribute to AE of the HLA-B gene in lung cells. Our analyses provide a new insight into allelic influence on the HLA expression in association with SARS-CoV-2 and other common viral infectious diseases.

Influence of WC Particle Size on the Mechanical Properties and Residual Stress of HVOF Thermally Sprayed WC-10Co-4Cr Coatings.

Cermet coatings deposited using high-velocity oxy-fuel (HVOF) are widely used due to their excellent wear and corrosion resistance. The new agglomeration-rapid sintering method is an excellent candidate for the preparation of WC-Co-Cr feedstock powders. In this study, four different WC-10Co-4Cr feedstock powders containing WC particles of different sizes were prepared by the new agglomeration-rapid sintering method and deposited on steel substrates using the HVOF technique. The microstructures and mechanical properties of the coatings were investigated using scanning electron microscopy, X-ray diffraction, nanoindentation, and Vickers indentation. The through-thickness residual stress profiles of the coatings and substrate materials were determined using neutron diffraction. We found that the microstructures and mechanical properties of the coatings were strongly dependent on the WC particle size. Decarburization and anisotropic mechanical behaviors were exhibited in the coatings, especially in the nanostructured coating. The coatings containing nano- and medium-sized WC particles were dense and uniform, with a high Young's modulus and hardness and the highest fracture toughness among the four coatings. As the WC particle size increased, the compressive stress in the coating increased considerably. Knowledge of these relationships enables the optimization of feedstock powder design to achieve superior mechanical performance of coatings in the future.

Development and evaluation of an inactivated coxsackievirus A16 vaccine in gerbils.

Coxsackievirus A16 (CVA16) is one of the major pathogens responsible for human hand, foot, and mouth disease (HFMD), which has threatened the health of young children, particularly in Asia-Pacific nations. Vaccination is an effective strategy for protecting children from CVA16 infection. However, there is currently no licensed CVA16 vaccine for use in humans. In this study, we isolated a high-growth CVA16 virus strain in MRC-5 cells and developed an MRC-5-adapted vaccine candidate strain termed CVA16-393 via two rounds of plaque purification. The CVA16-393 strain was grouped into the B1b subgenotype and grew to a titre of over 107 TCID50/ml in MRC-5 cells. The VP1 gene region of this strain, which contains the major neutralizing epitopes, displayed high stability during serial passages. The inactivated whole-virus vaccine produced by the CVA16-393 strain induced an effective neutralizing antibody response in Meriones unguiculatus (gerbils) after two doses of intraperitoneal inoculation. One week after the booster immunization, the geometric mean titres of the neutralizing antibodies for the 10246, 40812TXT, 11203SD, TJ-224 and CA16-194 strains from different regions of China were 137.8, 97.8, 113.4, 64.1 and 122.3, respectively. A CVA16 vaccine dose above 25 U was also able to provide 100% cross-protection against lethal challenges with these five clinical strains in gerbils. Immunization at a one-week interval could maintain a high level of neutralizing antibody titres for at least 8 weeks. Thus, the vaccine produced by this CVA16-393 strain might be promising.

Immunogenicity and immune-persistence of the CoronaVac or Covilo inactivated COVID-19 Vaccine: a 6-month population-based cohort study.

Background: Owing to the coronavirus disease 2019 (COVID-19) pandemic and the emergency use of different types of COVID-19 vaccines, there is an urgent need to consider the effectiveness and persistence of different COVID-19 vaccines. Methods: We investigated the immunogenicity of CoronaVac and Covilo, two inactivated vaccines against COVID-19 that each contain inactivated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The levels of neutralizing antibodies to live SARS-CoV-2 and the inhibition rates of neutralizing antibodies to pseudovirus, as well as the immunoglobulin (Ig)G and IgM responses towards the spike (S) and nucleocapsid (N) protein of SARS-CoV-2 at 180 days after two-dose vaccination were detected. Results: The CoronaVac and Covilo vaccines induced similar antibody responses. Regarding neutralizing antibodies to live SARS-CoV-2, 77.9% of the CoronaVac vaccine recipients and 78.3% of the Covilo vaccine recipients (aged 18-59 years) seroconverted by 28 days after the second vaccine dose. Regarding SARS-CoV-2-specific antibodies, 97.1% of the CoronaVac vaccine recipients and 95.7% of the Covilo vaccine recipients seroconverted by 28 days after the second vaccine dose. The inhibition rates of neutralizing antibody against a pseudovirus of the SARS-CoV-2 Delta variant were significantly lower compared with those against a pseudovirus of wildtype SARS-CoV-2. Associated with participant characteristics and antibody levels, persons in the older age group and with basic disease, especially a chronic respiratory disease, tended to have lower anti-SARS-CoV-2 antibody seroconversion rates. Conclusion: Antibodies that were elicited by these two inactivated COVID-19 vaccines appeared to wane following their peak after the second vaccine dose, but they persisted at detectable levels through 6 months after the second vaccine dose, and the effectiveness of these antibodies against the Delta variant of SARS-CoV-2 was lower than their effectiveness against wildtype SARS-CoV-2, which suggests that attention must be paid to the protective effectiveness, and its persistence, of COVID-19 vaccines on SARS-CoV-2 variants.