Sulfur Poisoning and Self-Recovery of Single-Site Rh1/Porous Organic Polymer Catalysts for Olefin Hydroformylation

Sulfur poisoning and regeneration are global deadly challenges for metal catalysts even at the ppm level. Fewer light was shed on the sulfur poisoning of single-metal-site catalysts and their regeneration. Herein, sulfur poisoning but self-recovery are first presented on an industrialized single-Rh-site catalyst (Rh1/POPs). A decreased turnover frequency of Rh1/POPs from 4317 h-1 to 318 h-1 was observed in a 1000 ppm H2S co-feed for ethylene hydroformylation, but it self-recovered to 4527 h-1 after withdrawal of H2S, while the rhodium nanoparticles demonstrated poor activity and self-recovery ability. H2S reduced the charge density of the single Rh atom and lowered its Gibbs free energy with the formation of inactive (SH)Rh(CO)(PPh3-frame)2, which could be regenerated to active HRh(CO)(PPh3-frame)2 after withdrawing H2S. The mechanism and the sulfur-related structure-activity relationship were highlighted. This work provides a forward understanding of the heterogeneous ethylene hydroformylation and the sulfur-poisoned regeneration in the catalysis science of single-atom catalysts.

Full Metal Species Quantification of Supported Catalysts: Beyond Metal Dispersion

Metal dispersion is a key concept in the heterogeneous catalysis. The conventional approach for its estimation strongly relies on chemisorption with different probe molecules. Albeit it can generally provide an 'averaged' value in a cost-effective manner, the inhomogeneity of the metal species and the complicated metal-support interactions pose formidable challenges for the accurate determination. Full metal species quantification (FMSQ) is introduced as an advanced method to depict the whole distribution of the metal species, ranging from single atoms to clusters and nanoparticles, in a practical solid catalyst. In this approach, automated analysis of massive high-angle annular dark field scanning transmission electron microscopic images is realized through algorithms specialized in combining the electron microscopy-based atom recognition statistics and deep learning-driven nanoparticle segmentation. FMSQ can circumvent the drawbacks of chemisorption, allowing more reliable structure-performance relationships beyond the metal size.

[Dexmedetomidine can not reduce the incidence of acute and chronic kidney disease after laparoscopic radical nephrectomy: a propensity score matching-based analysis]

OBJECTIVE

To investigate the effect of dexmedetomidine (DEX) on renal function after laparoscopic radical nephrectomy.

METHODS

We reviewed the clinical data of 282 patients with renal cell carcinoma (RCC), who underwent laparoscopic radical nephrectomy (LRN) in the Department of Urology, Third Medical Center of PLA General Hospital from November, 2020 and June, 2022.According to whether DEX was used during the operation, the patients were divided into DEX group and control group, and after propensity score matching, 99 patients were finally enrolled in each group.The incidence of acute kidney injuries were compared between the two groups.Serum creatinine (sCr) data within 3 months to 1 year after the operation were available in 51 patients, including 26 in DEX group and 25 in the control group, and the incidence of chronic kidney disease (CKD) was compared between the two groups.

RESULTS

After propensity score matching and adjustment for significant covariates, there were no significant differences in postoperative levels of sCr, cystatin C (CysC), β2-microglobulin (β2-MG), hemoglobin (Hb), or C-reactive protein (CRP), extubation time, incidence of AKI, or length of hospital stay between the two groups (P>0.05).The intraoperative urine volume was significantly higher in DEX group than in the control group (P < 0.05).A significant correlation between AKI and CKD was noted in the patients (P < 0.05).The incidence of CKD did not differ significantly between the two groups (P>0.05).

CONCLUSION

DEX can not reduce the incidence of AKI or CKD after LRN.

Measurements of the Electric and Magnetic Form Factors of the Neutron for Timelike Momentum Transfer

We present the first measurements of the electric and magnetic form factors of the neutron in the timelike (positive q^{2}) region as function of four-momentum transfer. We explored the differential cross sections of the reaction e^{+}e^{-}→n[over ¯]n with data collected with the BESIII detector at the BEPCII accelerator, corresponding to an integrated luminosity of 354.6  pb^{-1} in total at twelve center-of-mass energies between sqrt[s]=2.0-2.95  GeV. A relative uncertainty of 18% and 12% for the electric and magnetic form factors, respectively, is achieved at sqrt[s]=2.3935  GeV. Our results are comparable in accuracy to those from electron scattering in the comparable spacelike region of four-momentum transfer. The electromagnetic form factor ratio R_{em}≡|G_{E}|/|G_{M}| is within the uncertainties close to unity. We compare our result on |G_{E}| and |G_{M}| to recent model predictions, and the measurements in the spacelike region to test the analyticity of electromagnetic form factors.

Observation of a New X(3872) Production Process e^{+}e^{-}→ωX(3872)

Using 4.7  fb^{-1} of e^{+}e^{-} collision data at center-of-mass energies from 4.661 to 4.951 GeV collected by the BESIII detector at the BEPCII collider, we observe the X(3872) production process e^{+}e^{-}→ωX(3872) for the first time. The significance is 7.8σ, including both the statistical and systematic uncertainties. The e^{+}e^{-}→ωX(3872) Born cross section and the corresponding upper limit at 90% confidence level at each energy point are reported. The line shape of the cross section indicates that the ωX(3872) signals may be from the decays of some nontrivial structures.

[Mutation characteristics of osteosarcoma: a single center study of 64 cases using next-generation sequencing]

Objective: To investigate the distribution and characteristics of gene mutations in osteosarcoma, and to analyze the frequency and types of detectable mutations, and to identify potential targets for individualized treatment of osteosarcoma. Methods: The fresh tissue or paraffin-embedded tissue samples of 64 cases of osteosarcoma that were surgically resected or biopsied and then subject to next generation sequencing, were collected from Beijing Jishuitan Hospital, China from November 2018 to December 2021. The tumor DNA was extracted to detect the somatic and germline mutations using targeted sequencing technology. Results: Among the 64 patients, 41 were males and 23 were females. The patient age ranged from 6 to 65 years with a median age of 17 years, including 36 children (under 18 years old) and 28 adults. There were 52 cases of conventional osteosarcoma, 3 cases of telangiectatic osteosarcoma, 7 cases of secondary osteosarcoma, and 2 cases of parosteosarcoma. The detection rate of gene mutations was overall 84.4% (54/64). There were 324 variations in 180 mutated genes, including 125 genes with copy number variations, 109 single nucleotide variants, 83 insertions or deletions, and 7 gene fusions. The most common mutated genes were TP53, VEGFA, CCND3, ATRX, MYC, RB1, PTEN, GLI1, CDK4 and PTPRD. Among them, TP53 had the highest mutation rate (21/64, 32.8%), single nucleotide variant was the main mutation type (14/23, 60.9%), and 2 cases carried the TP53 germline mutation. VEGFA and CCND3 showed copy number amplification simultaneously in 7 cases. Conclusions: The high-frequency mutation of TP53 suggests that it plays an important role in the pathogenesis and development of osteosarcoma. VEGFA, CCND3 and ATRX are mutated genes in osteosarcoma and worthy of further studies. Combination of pathologic diagnosis and next generation sequencing with clinical practice can guide individualized treatment for patients with refractory, recurrent and metastatic osteosarcoma.

Asthenopia prevalence and vision impairment severity among students attending online classes in low-income areas of western China during the COVID-19 pandemic

INTRODUCTION

This study explored the impact of online learning during the coronavirus disease 2019 (COVID-19) pandemic on asthenopia and vision impairment in students, with the aim of establishing a theoretical basis for preventive approaches to vision health.

METHODS

This balanced panel study enrolled students from western rural China. Participant information was collected before and during the COVID-19 pandemic via questionnaires administered at local vision care centres, along with clinical assessments of visual acuity. Paired t tests and fixed-effects models were used to analyse pandemic-related differences in visual status.

RESULTS

In total, 128 students were included (mean age before pandemic, 11.82 ± 1.46 years). The mean total screen time was 3.22 ± 2.90 hours per day during the pandemic, whereas it was 1.97 ± 1.90 hours per day in the pre-pandemic period (P<0.001). Asthenopia prevalence was 55% (71/128) during the pandemic, and the mean visual acuity was 0.81 ± 0.30 logarithm of the minimum angle of resolution; these findings indicated increasing vision impairment, compared with the pre-pandemic period (both P<0.001). Notably, asthenopia prevalence increased by two- to three-fold, compared with the pre-pandemic period. An increase in screen time while learning was associated with an increase in asthenopia prevalence (P=0.034).

CONCLUSION

During the COVID-19 pandemic, students spent more time on online classes, leading to worse visual acuity and vision health. Students in this study reported a significant increase in screen time, which was associated with increasing asthenopia prevalence and worse vision impairment. Further research is needed regarding the link between online classes and vision problems.

The role of TLR4-mediated MyD88/TRAF6/NF-κB signaling and pIgR intestinal expression in chicks during Salmonella enteritidis infection

To observe the effect of Salmonella enteritidis (SE)-induced inflammation on pIgR expression in jejunum and ileum. Salmonella enteritidis was orally administered to 7-day old Hyline chicks, which were killed after 1d,3d,7d and 14d. The mRNA expression of TLR4,MyD88,TRAF6,NF-κB, and pIgR was detected by real-time RT-PCR, and pIgR protein was detected by Western blotting. The TLR4 signaling pathway was activated, the mRNA expression of the pIgR in jejunum and ileum was increased, and pIgR protein in jejunum and ileum was up-regulated by SE. In SE-treated chicks,the pIgR in jejunum and ileum was up-regulated on mRNA,and protein level,associated with activation of the TRL4-mediated MyD88/TRAF6/NF-κB signaling pathway, which identifies this as a novel pIgR-related pathway to TLR4 activation.

Observation of Three Charmoniumlike States with J^{PC}=1^{--} in e^{+}e^{-}→D^{*0}D^{*-}π^{+}

The Born cross sections of the process e^{+}e^{-}→D^{*0}D^{*-}π^{+} at center-of-mass energies from 4.189 to 4.951 GeV are measured for the first time. The data samples used correspond to an integrated luminosity of 17.9  fb^{-1} and were collected by the BESIII detector operating at the BEPCII storage ring. Three enhancements around 4.20, 4.47, and 4.67 GeV are visible. The resonances have masses of 4209.6±4.7±5.9  MeV/c^{2}, 4469.1±26.2±3.6  MeV/c^{2}, and 4675.3±29.5±3.5  MeV/c^{2} and widths of 81.6±17.8±9.0  MeV, 246.3±36.7±9.4  MeV, and 218.3±72.9±9.3  MeV, respectively, where the first uncertainties are statistical and the second systematic. The first and third resonances are consistent with the ψ(4230) and ψ(4660) states, respectively, while the second one is compatible with the ψ(4500) observed in the e^{+}e^{-}→K^{+}K^{-}J/ψ process. These three charmoniumlike ψ states are observed in the e^{+}e^{-}→D^{*0}D^{*-}π^{+} process for the first time.

[Clinical efficacy analysis of TMF for the treatment of hyperviremia HBeAg-positive chronic hepatitis B patients with incomplete response to first-line oral antiviral nucleos(t)ide analogues]

Objective: To prospectively explore the treatment strategies for clinical difficulties in patients with hyperviremia HBeAg-positive chronic hepatitis B with incomplete response to first-line nucleos(t)ide analogues (NAs). Methods: Patients with hyperviremia HBeAg-positive chronic hepatitis B were treated with first-line NAs, including entecavir, tenofovir disoproxil fumarate (TDF), tenofovir alafenamide fumarate (TAF) for 48 weeks or more. Tenofovir amibufenamide (TMF) or TAF therapy was changed when HBV DNA remained positive and then divided into a TMF group and a TAF group. Clinical efficacy of treatment was evaluated at 24 and 48 weeks, including HBV DNA undetectable rates and virological and serological responses in both patient groups. Results: In the TMF group and the TAF groups, 30 and 26 cases completed 24-week follow-up, while 18 and 12 cases completed 48-week follow-up. There were no statistically significant differences in baseline HBV DNA, HBsAg, and HBeAg levels between the two groups before switching to TMF/TAF therapy (P > 0.05). At 24 weeks of treatment, 19 (19/30, 63.33%) cases in the TMF group had HBV DNA negative conversion, while 14 (14/26, 53.85%) cases in the TAF group had HBV DNA negative conversion (P > 0.05). Among the patients who completed 48 weeks of follow-up, 15 (15/18, 83.33%) cases in the TMF group and 7 (7/12, 58.33%) cases in the TAF group had negative HBV DNA tests (P > 0.05). The changes in HBsAg and HBeAg levels between the two groups of patients at 24 and 48 weeks of treatment were not statistically significant compared to baseline (P > 0.05). Conclusion: TMF is effective in treating patients with hyperviremia HBeAg-positive CHB with an incomplete response to first-line NAs treatment, but there is no significant difference compared to TAF.

A review of Co/Co2C-based catalysts in Fischer-Tropsch synthesis: from fundamental understanding to industrial applications

Fischer-Tropsch synthesis (FTS), which provides a green route to the production of clean fuels and fine chemicals, represents some significant applications of catalytic materials and processes in the chemical industry. FTS reactions show a diversity of mechanisms, involve various catalytic materials, and offer options for continuous investigation. Cobalt-based catalysts have been widely used for Fischer-Tropsch synthesis both in academia and in industry. This mini-review will focus on relevant research achievements in cobalt-based FTS catalysts by our group in the Dalian Institute of Chemical Physics (DICP). Specific contents will include the development of Co/Co₂C-based nano-catalysts (i) for the highly selective synthesis of clean fuels over Co-based catalysts supported by carbon materials and (ii) for the synthesis of linear α-alcohols and olefins over Co-Co₂C-based catalysts supported by carbon materials. The direct synthesis of linear α-alcohols from syngas using a Co-Co₂C/AC catalyst is highlighted. The innovative work of FTS using activated carbon (AC)-supported Co/Co₂C-based nano-catalysts could bring some insight into new FTS catalyst designs.

Investigation of the relationships among respiratory syncytial virus infection, T cell immune response and intestinal flora

The aim of this work was to evaluate the relationships among respiratory syncytial virus infection, T cell immune response and intestinal flora. Peer-reviewed papers published in English were collected through extensive searches performed in PubMed, Web of Science, Google Scholar, and China National Knowledge Infrastructure databases. The articles were reviewed to extract relevant information on the immune responses of Th1/Th2 and Treg/Th17 to respiratory syncytial virus infection in the body. RSV (Respiratory syncytial virus, RSV) infection leads to imbalance between Th1/Th2 and Treg/Th17 immune cells, resulting in Th2 or Th17 dominant immune responses, which can generate immune disorder and aggravate clinical symptoms. Intestinal micro-organisms play very important roles in maintaining stable immune environment, stimulating immune system maturation and balancing Th1/Th2 and Treg/Th17 immune systems in children. In our review of various papers from around the world, we speculated that the steady state of intestinal bacteria was disturbed after children got infected with RSV, resulting in intestinal flora disorder. Then, the imbalance between Th1/Th2 and Treg/Th17 immune cells was increased. Both intestinal flora disorder and RSV infection could cause cellular immunity imbalance of Th1/Th2 or Treg/Th17, eventually leading to disease deterioration and even a vicious cycle. Normal intestinal flora can maintain immune system stability, regulate the dynamic balance of Th1/Th2 and Treg/Th17 and prevent or mitigate adverse consequences of RSV infection. Because probiotics can improve intestinal barrier function and regulate immune response, they can effectively be used to treat children with recurrent respiratory tract infections. Using conventional antiviral therapy strategy supplemented with probiotics in the treatment of clinical RSV infection may be better for the body.

Evidence for the Cusp Effect in η' Decays into ηπ^{0}π^{0}

Using a sample of 4.3×10^{5} η^{'}→ηπ^{0}π^{0} events selected from the ten billion J/ψ event dataset collected with the BESIII detector, we study the decay η^{'}→ηπ^{0}π^{0} within the framework of nonrelativistic effective field theory. Evidence for a structure at π^{+}π^{-} mass threshold is observed in the invariant mass spectrum of π^{0}π^{0} with a statistical significance of around 3.5σ, which is consistent with the cusp effect as predicted by the nonrelativistic effective field theory. After introducing the amplitude for describing the cusp effect, the ππ scattering length combination a_{0}-a_{2} is determined to be 0.226±0.060_{stat}±0.013_{syst}, which is in good agreement with theoretical calculation of 0.2644±0.0051.

[Depressive symptoms are not associated with risks of rapid renal function decline or chronic kidney disease in middle-aged and elderly with normal kidney function: a longitudinal investigation]

OBJECTIVE

To explore the association between depressive symptoms and the risks of rapid decline in renal function and chronic kidney disease (CKD) in middle-aged and elderly with normal kidney function.

METHODS

The residents aged 40- 75 years with eGFR≥60 mL·min^-1·1.73 m^-2 without proteinuria in Lanzhou region, who participated in the "REACTION" study carried out in 2011, were selected and followed up in 2014. A total of 4961 individuals with complete and qualified data from the two surveys were included in the subsequent analysis. Based on PHQ-9 questionnaire scores, the baseline population was divided into two groups with and without depressive symptoms. Cox proportional hazard analysis was used to compare the incidences of rapid renal function decline and CKD between the two groups and study the association of depressive symptoms with the risk of these renal conditions.

RESULTS

PHQ-9 questionnaire scores were not found to correlate with baseline SCr, ALB, UACR or eGFR levels among the participarts (P>0.05). After a mean follow-up time of 3.4±0.6 years, 33.9% of the participants with depressive symptoms at baseline experienced a rapid decline in renal function and 3.6% progressed to CKD. During the follow-up, the incidence of rapid decline in renal function and the risk of developing CKD were not found to correlate with depressive symptoms in these participants (P>0.05) regardless of the type of the depressive syndromes.

CONCLUSION

Depressive symptoms are not associated with the risks of rapid renal function decline or progression to CKD in middle-aged and elderly with normal kidney function.

[Pediatric myofibroma/myofibromatosis of the soft tissue and bone: a clinicopathological analysis of 28 cases]

Objective: To investigate the clinicopathological features, diagnosis and differential diagnosis of pediatric myofibroma/myofibromatosis of the soft tissue and bone. Methods: All cases of pediatric myofibroma/myofibromatosis of the soft tissue and bone diagnosed between January 2011 and December 2018 were retrieved from the surgical pathology records in the Department of Pathology, Beijing Jishuitan Hospital, Beijing, China. Clinical and radiological data were collected. H&E and immunohistochemistry were used to examine histological and immunophenotypic features and to make the diagnosis and differential diagnosis. The relevant literature was also reviewed. Results: Twenty-eight cases of pediatric myofibroma/myofibromatosis of the soft tissue and bone were respectively collected. The patients' ages ranged from 2 months to 14 years, with a mean age of 7 years. There were 7 females and 21 males. There were 12 cases located in soft tissue, including the finger (n=9), upper arm (n=1) and foot (n=2). There were 14 cases located in the bone of limb, including the femur (n=8), tibia (n=4), clavicle (n=2), fibula (n=2) and radius (n=1). There were 2 cases of myofibromatosis involving multiple bones. Radiology showed lytic lesions in the bone. The proliferation of spindle-shaped myofibroblasts arranged in fascicles with indistinct eosinophilic cytoplasm and bland nuclei, with no pleomorphism and cytological atypia. The characteristic histologic structure was the biphasic nodular growth pattern with cellular and paucicellular regions. The tumors might arrange in a hemangiopericytoma-like pattern. The stroma varied between dense fibrosis and myxoid changes. The reactive new bone formation and inflammatory cell infiltration also existed. Immunohistochemical study showed that the SMA was positive. The surgical resections were performed. One of the patients had tumor recurrence as a result of 11-month follow-up. Conclusions: The pediatric myofibroma/myofibromatosis of the soft tissue and bone is a very rare benign tumor and has a good prognosis. It has a characteristic morphology and its differential diagnosis from other spindle cell tumors could be made with the immunohistochemical analysis.

Maize resistance to witchweed through changes in strigolactone biosynthesis

Maize (Zea mays) is a major staple crop in Africa, where its yield and the livelihood of millions are compromised by the parasitic witchweed Striga. Germination of Striga is induced by strigolactones exuded from maize roots into the rhizosphere. In a maize germplasm collection, we identified two strigolactones, zealactol and zealactonoic acid, which stimulate less Striga germination than the major maize strigolactone, zealactone. We then showed that a single cytochrome P450, ZmCYP706C37, catalyzes a series of oxidative steps in the maize-strigolactone biosynthetic pathway. Reduction in activity of this enzyme and two others involved in the pathway, ZmMAX1b and ZmCLAMT1, can change strigolactone composition and reduce Striga germination and infection. These results offer prospects for breeding Striga-resistant maize.

Carbonaceous deposits on cobalt particles reverse the catalytic patterns in butadiene hydrogenation

We report the decisive roles of the in situ formed carbonaceous deposits in dramatically reversing the performance of a cobalt nanoparticle catalyst in butadiene hydrogenation. A delicate balance between the...

Genetic polymorphisms in MIR1208 and MIR5708 are associated with susceptibility to COPD in the Chinese population

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a complex disease characterized by limited airflow and is influenced by genetic and environmental factors. The purpose of this study was to investigate the effects of gene polymorphisms in MIR5708 and MIR1208 on COPD risk.

METHODS

Four single nucleotide polymorphisms (SNPs) in MIR5708 (rs6473227 and rs16907751) and MIR1208 (rs2608029 and rs13280095) were selected and genotyped among 315 COPD patients and 314 healthy controls using the Agena MassARRAY platform. SPSS 18.0 was used for statistical analysis and data processing. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to assess the association between genetic variants of MIR1208 and MIR5708 and COPD risk.

RESULTS

The results suggested that rs16907751 variants in MIR5708 contributed to an increased susceptibility to COPD in the allelic (P = 0.001), co-dominant (homozygous) (P = 0.001), dominant (P = 0.017), recessive (P = 0.002), and additive (P = 0.002) models. The effects of MIR5708 and MIR1208 gene polymorphisms on the risk of COPD were age-, sex-, smoking status-, and BMI-related. Furthermore, the C-A and G-A haplotypes of rs2608029 and rs13280095 in MIR1208 were identified as risk factors for COPD in the population over 70 years (P = 0.029) and in women (P = 0.049), respectively. Finally, significant associations between rs16907751genotypes with pulse rate and forced expiratory volume in 1 s were found among COPD patients.

CONCLUSION

Genetic polymorphisms in MIR5708 and MIR1208 are associated with increased risk of COPD in China.

[The diagnostic value of CCNB3 and BCOR expression in BCOR-CCNB3 sarcoma]

Objective: To investigate the diagnostic value of expression of CCNB3 and BCOR in BCOR-CCNB3 sarcoma (BCS). Methods: Fifteen cases of BCS confirmed by fluorescence in situ hybridization (FISH) and/or reverse transcription-polymerase chain reaction (RT-PCR) from January 2014 to October 2021 at Beijing Jishuitan Hospital were collected. Immunohistochemical EnVision method was used to detect the expression of CCNB3 and BCOR in 15 cases of BCS and in 65 non-BCS tumors (54 cases of Ewing's sarcoma, 5 cases of CIC rearranged sarcoma, 4 cases of synovial sarcoma, 1 case of mesenchymal chondrosarcoma and 1 case of soft tissue clear cell sarcoma). Results: Immunohistochemical staining for CCNB3 revealed strongly diffuse nuclear staining in 14 of 15 (14/15) BCS cases, whereas none of the 65 non-BCS tumors showed any staining. Immunohistochemical staining for BCOR showed strongly diffuse nuclear staining in 11 (11/14) BCS cases; seven of the 65 (7/65, 10.8%) non-BCS tumors showed variable staining (five cases of Ewing sarcoma, one cases of synovial sarcoma, and one case of mesenchymal chondrosarcoma). The sensitivity and specificity of CCNB3 in diagnosing BCS were 93.3% and 100% and these of BCOR were 78.6% and 89.2%, respectively. Conclusions: CCNB3 is a highly sensitive and specific marker for BCS.The antibody may help screening BCS.

[Characteristics and related factors of viral nucleic acid negative conversion in children infected with Omicron variant strain of SARS-CoV-2]

Objective: To understand the characteristics and associated factors of viral nucleic acid conversion in children infected with Omicron variant strain of SARS-CoV-2 in Shanghai. Methods: The clinical symptoms, laboratory results and other data of 177 children infected with SARS-CoV-2 who were hospitalized in Shanghai Children's Hospital, School of Medicine, Shanghai Jiao Tong University (designated hospital for SARS-CoV-2 infection in Shanghai) from April 25 to June 8, 2022 were retrospectively analyzed. According to the chest imaging findings, the children were divided into mild and common type groups. According to their age, the unvaccinated children were divided into<3 years old group and 3-<18 years old group. According to the vaccination status, the children aged 3-<18 year were divided into non-vaccination group, 1-dose vaccination group and 2-dose vaccination group. Comparison between groups was performed by independent sample t-test and analysis of variance, and multivariate linear regression analysis was used for multivariate analysis. Results: Among the 177 children infected with Omicron variant of SARS-CoV-2, 96 were males and 81 were females, aged 3 (1, 6) years. The time of viral nucleic acid negative conversion was (10.3±3.1) days. The 177 children were 138 cases of mild type and 39 cases of common type. Among the children aged 3-<18 years old, 55 cases were not vaccinated, 5 cases received 1-dose and 36 cases received 2-dose vaccination. Among the 36 children who received 2 doses of vaccination, the time of viral nucleic acid negative conversion was shorter in those vaccinated within 6 months than those over 6 months ((7.1±1.9) vs. (10.8±3.0) d, t=-3.23, P=0.004). Univariate analysis showed that the time of nucleic acid negative conversion of SARS-CoV-2 was associated with age, underlying diseases, gastrointestinal symptoms, white blood cell count, proportion of neutrophils, proportion of lymphocytes, and the number of doses of SARS-CoV-2 vaccine (t=3.87, 2.55, 2.04, 4.24, 3.51, 2.92, F=16.27, all P<0.05). Multiple linear regression analysis showed that older age (β=-0.33, 95% CI -0.485--0.182, P<0.001) and more doses of vaccination (β=-0.79, 95% CI -1.463--0.120, P=0.021) were associated with shortened nucleic acid negative conversion time in children, while lower lymphocyte proportion (β=-0.02, 95% CI -0.044--0.002, P=0.031) and underlying diseases (β=1.52, 95% CI 0.363-2.672, P=0.010) were associated with prolonged nucleic acid negative conversion time in children. Conclusion: The children infected with Omicron variant of SARS-CoV-2 with reduced lymphocyte proportion and underlying diseases may have longer time of viral nucleic acid negative conversion,while children with older age and more doses of vaccination may have shorter time of viral nucleic acid negative conversion.