[Epidemiological survey of hepatitis B and analysis of hepatitis B vaccine coverage rate among children aged 1-14 years in Lhasa in 2006, 2014 and 2020].

In 2006, 2014 and 2020, the positive rates of HBsAg in 560, 384 and 402 children aged 1 to 14 years were 4.5%, 2.6% and 2.5%, respectively, with no statistically significant differences (P>0.05). The positive rate of anti-HBs was highest in 2014 (57.8%) and lowest in 2006 (34.1%) (P<0.05). The positive rate of anti-HBc was highest in 2006 (15.7%), and decreased in 2014 (7.8%) and 2020 (5.7%) (P<0.001). The timely rate of the first dose of hepatitis B vaccine for children in Lhasa in 2006, 2014 and 2020 was 7.7% (43/560), 50.3% (193/384) and 94.8% (381/402), respectively. The overall vaccination rates were 15.4% (86/560), 35.2% (135/384) and 96.0% (386/402), respectively, showing a trend of gradual increases (χtrend values were 718.63 and 589.59, both P values<0.001).

Epidemiological and clinical characteristics of patients with COVID-19 from a designated hospital in Hangzhou City: a retrospective observational study.

INTRODUCTION: The outbreak of coronavirus disease 2019 (COVID-19) has exerted a heavy burden on public health worldwide. We aimed to investigate the epidemiological and clinical characteristics of patients with COVID-19 in a designated hospital in Hangzhou, China. METHODS: This was a retrospective study that included laboratory-confirmed cases of COVID-19 in XiXi Hospital of Hangzhou from 15 January 2020 to 30 March 2020. We reviewed and analysed the epidemiological, demographic, clinical, radiological, and laboratory features involving these cases. Age-tratification analysis was also implemented. RESULTS: We analysed 96 confirmed cases. The patients had a mean age of 43 years, with six patients younger than 18 years and 14 patients older than 60 years. No significant gender difference was discovered. Co-morbidities were commonly observed in patients aged over 40 years. Twenty eight of the patients had travelled from Wuhan City, and 51 patients were infected through close contact. Familial clusters accounted for 48 of the cases. The mean incubation time was 7 days, and the symptoms were mainly fever, cough, fatigue, and sore throat. Lymphocytopenia was observed predominantly in patients aged over 60 years. Fifty five patients presented with bilateral pulmonary lesions. The radiological changes were typically distributed in the subpleural area, and pleural effusion rarely occurred. All patients were discharged successfully. CONCLUSION: During the early stage of the COVID-19 outbreak, half of the patients from a designated hospital in Hangzhou City were discovered as familial clusters. Therefore, strict prevention and control measures during self-isolation should be implemented. Patients aged over 60 years who had underlying co-morbidities were prone to lymphocytopenia and severe infection.

Transcatheter aortic valve replacement in atypical valve anatomy using the Lotus valve : A Chinese single-center experience.

BACKGROUND: In the West, the safety and efficacy of the Lotus valve have been demonstrated; however, data in the Chinese population are still lacking. Few studies have compared the clinical outcomes of transcatheter aortic valve replacement (TAVR) with the Lotus valve in patients with bicuspid or tricuspid aortic valve stenosis. Our aim was to assess TAVR outcomes with the Lotus aortic valve in a Chinese patient cohort. METHODS: In total, 23 symptomatic, high-surgical risk patients with severe aortic valve stenosis were enrolled. Among them, nine patients (39%) had bicuspid aortic valves, and three patients had a large annulus dimension. The Lotus valve was successfully implanted in all patients. To facilitate accurate positioning, partial re-sheathing was attempted in ten patients (43.5%), while one patient had a full retrieval. One-year clinical follow-up was completed in all patients. RESULTS: There were no deaths, strokes, or major adverse cardiac and cerebrovascular events in 22 of the 23 patients at 30 days; the all-cause mortality rate at 1 year was 4.4% (1 of 23 patients). The mean aortic valve gradient decreased from 51.5 ± 8.8 mm Hg at baseline to 13.4 ± 4.9 mm Hg (p < 0.001) and the valve area increased from 0.6 ± 0.2 cm2 to 1.5 ± 0.4 cm2 (p < 0.001) at 30 days. Paravalvular leakage was absent or mild (22%), and no patient had severe paravalvular leakage. Six patients (26.1%) required a postprocedural pacemaker. There was no difference regarding the procedural and the 1­year outcomes between patients with bicuspid and tricuspid aortic valve stenosis. CONCLUSION: Our single-center experience demonstrated that the Lotus valve is feasible and effective for Chinese patients with aortic valve stenosis, including atypical cases with bicuspid aortic valves or large aortic annulus size.

Species of Botryosphaeriaceae associated with citrus branch diseases in China.

Citrus is an important and widely cultivated fruit crop in South China. Although the species of fungal diseases of leaves and fruits have been extensively studied, the causal organisms of branch diseases remain poorly known in China. Species of Botryosphaeriaceae are known as important fungal pathogens causing branch diseases on citrus in the USA and Europe. To determine the diversity of Botryosphaeriaceae species associated with citrus branch diseases in China, surveys were conducted in the major citrus-producing areas from 2017 to 2020. Diseased tissues were collected from twigs, branches and trunks with a range of symptoms including cankers, cracking, dieback and gummosis. Based on morphological characteristics and phylogenetic comparison of the DNA sequences of the internal transcribed spacer region (ITS), the translation elongation factor 1-alpha gene (tef1), the ß-tubulin gene (tub2) and the DNA-directed RNA polymerase II second largest subunit (rpb2), 111 isolates from nine provinces were identified as 18 species of Botryosphaeriaceae, including Botryosphaeria dothidea, B. fabicerciana, Diplodia seriata, Dothiorella alpina, Do. plurivora, Lasiodiplodia citricola, L. iraniensis, L. microconidia, L. pseudotheobromae, L. theobromae, Neodeightonia subglobosa, Neofusicoccum parvum, and six previously undescribed species, namely Do. citrimurcotticola, L. guilinensis, L. huangyanensis, L. linhaiensis, L. ponkanicola and Sphaeropsis linhaiensis spp. nov. Botryosphaeria dothidea (28.8 %) was the most abundant species, followed by L. pseudotheobromae (23.4 %), which was the most widely distributed species on citrus, occurring in six of the nine provinces sampled. Pathogenicity tests indicated that all 18 species of Botryosphaeriaceae obtained from diseased citrus tissues in this study were pathogenic to the tested Citrus reticulata shoots in vitro, while not all species are pathogenic to the tested Cocktail grapefruit (C. paradisi × C. reticulata) shoots in vivo. In addition, Lasiodiplodia was the most aggressive genus both in vitro and in vivo. This is the first study to identify Botryosphaeriaceae species related to citrus branch diseases in China and the results provide a theoretical basis for the implementation of prevention and control measures. Citation: Xiao XE, Wang W, Crous PW, et al. 2021. Species of Botryosphaeriaceae associated with citrus branch diseases in China. Persoonia 47: 106-135. https://doi.org/10.3767/persoonia.2021.47.03.

Species of Botryosphaeriaceae associated with citrus branch diseases in China.

Citrus is an important and widely cultivated fruit crop in South China. Although the species of fungal diseases of leaves and fruits have been extensively studied, the causal organisms of branch diseases remain poorly known in China. Species of Botryosphaeriaceae are known as important fungal pathogens causing branch diseases on citrus in the USA and Europe. To determine the diversity of Botryosphaeriaceae species associated with citrus branch diseases in China, surveys were conducted in the major citrus-producing areas from 2017 to 2020. Diseased tissues were collected from twigs, branches and trunks with a range of symptoms including cankers, cracking, dieback and gummosis. Based on morphological characteristics and phylogenetic comparison of the DNA sequences of the internal transcribed spacer region (ITS), the translation elongation factor 1-alpha gene (tef1), the ß-tubulin gene (tub2) and the DNA-directed RNA polymerase II second largest subunit (rpb2), 111 isolates from nine provinces were identified as 18 species of Botryosphaeriaceae, including Botryosphaeria dothidea, B. fabicerciana, Diplodia seriata, Dothiorella alpina, Do. plurivora, Lasiodiplodia citricola, L. iraniensis, L. microconidia, L. pseudotheobromae, L. theobromae, Neodeightonia subglobosa, Neofusicoccum parvum, and six previously undescribed species, namely Do. citrimurcotticola, L. guilinensis, L. huangyanensis, L. linhaiensis, L. ponkanicola and Sphaeropsis linhaiensis spp. nov. Botryosphaeria dothidea (28.8 %) was the most abundant species, followed by L. pseudotheobromae (23.4 %), which was the most widely distributed species on citrus, occurring in six of the nine provinces sampled. Pathogenicity tests indicated that all 18 species of Botryosphaeriaceae obtained from diseased citrus tissues in this study were pathogenic to the tested Citrus reticulata shoots in vitro, while not all species are pathogenic to the tested Cocktail grapefruit (C. paradisi × C. reticulata) shoots in vivo. In addition, Lasiodiplodia was the most aggressive genus both in vitro and in vivo. This is the first study to identify Botryosphaeriaceae species related to citrus branch diseases in China and the results provide a theoretical basis for the implementation of prevention and control measures. Citation: Xiao XE, Wang W, Crous PW, et al. 2021. Species of Botryosphaeriaceae associated with citrus branch diseases in China. Persoonia 47: 106-135. https://doi.org/10.3767/persoonia.2021.47.03.

Analysis of evolution and genetic diversity of sweetpotato and its related different polyploidy wild species I. trifida using RAD-seq.

BACKGROUND: Sweetpotato (Ipomoea batatas (L.) Lam.) is one of the most important crops from the family of Convolvulaceae. It is widely reported that cultivated sweetpotato was originated from Ipomoea trifida. However, diploid, tetraploid and hexaploid I. trifida were found in nature. The relationship, between them, and among them and sweetpotato, is remaining unclear. RESULTS: In the present study, we detected the genome diversity and relationship of sweetpotato and different polyploidy types I. trifida using Restriction-site Associated DNA Sequencing (RAD-seq). A total of 38,605 RAD-tags containing 832,204 SNPs had been identified. These tags were annotated using five public databases, about 11,519 tags were aligned to functional genes in various pathways. Based on SNP genotype, phylogenetic relation analysis results confirmed that cultivated sweetpotato has a closer relationship with I. trifida 6× than with I. trifida 4X and I. trifida 2×. Besides, 5042 SSRs were detected in I. trifida 6×, and 3202 pairs of high-quality SSR primers were developed. A total of 68 primers were randomly selected and synthesized, of which 61 were successfully amplified. CONCLUSION: These results provided new evidence that cultivated sweetpotato originated from I. trifida 6×, and that I. trifida 6× evolved from I. trifida 4X and I. trifida 2×. Therefore, using I. trifida 6× as the model plant of sweetpotato research should be more practical than using I. trifida 2× in the future. Meanwhile, sequence information and markers from the present study will be helpful for sweetpotato and I. trifida studies in the future.

Prevalence and natural course of occult hepatitis B virus infection in residents of 2 communities of Wuwei City, Gansu Province, China.

Occult hepatitis B infection (OBI) is characterized by serum hepatitis B surface antigen (HBsAg) negative and hepatitis B virus (HBV) DNA positive (HBsAg-/HBV DNA+). Occult hepatitis B infection in community-based populations has been scarcely investigated, and OBI outcomes remain unclear, especially in Wuwei, a region located in Northwest China. This region is one of the areas in China that has the highest prevalence of chronic HBV infection. A prospective study was performed in the general population of 2 towns of Wuwei from June 2011 to May 2014. A questionnaire was used to collect demographic and medical data, and serum samples were collected from the participants and stored until analysis. DNA was detected using quantitative PCR (qPCR) or nested PCR, the HBV DNA from HBV DNA-positive or possible positive (below the detection limit) subjects was extracted and amplified by nested PCR, and the PCR products were sequenced. Sequence analysis was performed using the Mega 6.0 program and CLC sequence viewer software. Hepatitis B virus DNA was detected in 90 of 3,080 HBsAg-negative subjects, and the prevalence of OBI in the study population was 2.92% (90/3,080, 95% CI: 2.33%-3.51%). Hepatitis B virus genomes in 51 of 80 objects (63.75%) contained mutations in the "a" determinant of HBsAg. After 2 years follow-up, 42 of 90 HBV DNA of OBI subjects remained positive, and the natural clearance rate of OBI subjects was 53.3%. Occult hepatitis B infection prevalence in this cohort was much lower than chronic HBV infection in the same region. HBV DNA was cleared in most OBI subjects during the 2 year period. Our data suggest that some OBI may represent a late stage of resolving the HBV infection process.

Overt and occult hepatitis B virus infection among community children in Northwest China.

Although a universal newborn hepatitis B (HB) immunization programme has been implemented in China, hepatitis B virus (HBV) breakthrough infection, including HB surface antigen (HBsAg)-positive infection and occult HBV infection (OBI), still occurs during infancy or childhood. Obtaining the actual prevalence of HBV infection in general children is important for preventing and controlling the spread of HB. Accordingly, we investigated the prevalence of overt infection and OBI in community children and compared the serological and virological characteristics of OBI and HBsAg carrier children to clarify the mechanisms related to OBI. In total, 6 706 community children <12 years of age were included from a population-based HBV seroepidemiological investigation in Northwest China. The HBsAg carrier rate in community children was 1.60% (107/6706), and the anti-HBs positive rate was 57.35% (3846/6706). Additionally, 1192 HBsAg-negative children were examined for OBI using nested PCR. The prevalence of OBI in local children was 1.26% (15/1192), and the predominant OBI genotypes were C and D. The 15 OBI children and 29 HBsAg-positive children from the same population did not have a statistical significant difference in age, gender, alanine aminotransferase (ALT), proportion of anti-HBs or anti-HBc, viral genotypes or mutations. Children with chronic overt infection had higher viral loads than OBI children (P=.004). These results suggested that HBV overt and occult infection of children was more serious in underdeveloped north-west regions. HBV neonatal immunization and catch-up programmes should be strengthened and supplemented. None of specific viral mutations or genotypes related to OBI were found. OBI may be a specific stage of HBV infection.

[Comparison of aortic annular diameter defined by different measurement mordalities before transcatheter aortic valve implantation].

Objective: To compare aortic annular diameter measured by transthoracic echocardiography (TTE), transesophageal echocardiography (TEE), and multislice computed tomography (MSCT) in patients with severe aortic stenosis, and to evaluate the impact on selection of prosthetic valve type in transcatheter aortic valve implantation (TAVI). Methods: Clinical data of 138 patients with severe aortic stenosis referred for TAVI between January 2014 and June 2016 in our hospital were retrospectively analyzed.The difference of aortic annular diameter measured by TTE, TEE, and MSCT were compared.TTE was performed after TAVI to evaluate the accuracy of measurement before TAVI. Results: (1) Aortic annular diameter was (23.37±2.22) mm by TTE and (23.52±1.70) mm by TEE (P=0.12). Pearson correlation analysis showed that aortic annular diameter measured by TTE was correlated to that measured by TEE (r=0.87, P<0.05). (2)The long-axis diameter and the short-axis diameter measured by MSCT multiplanar reconstruction were significantly different ((27.86±2.87) mm vs. (21.91±2.53) mm, P<0.05). There was no significant difference between the mean of the long- and short-axis diameters and the diameter derived from cross-sectional area by MSCT ((24.92±2.38) mm vs. (24.84±2.25) mm, P=0.08). However, the diameter derived from the circumference ((25.35±2.34) mm) was significantly larger than the mean of the long- and short-axis diameters and the diameter derived from cross-sectional area by MSCT, and the difference were (0.43±0.62) mm and (0.51±0.62) mm respectively(both P<0.05). (3) Measurements of the aortic annulus diameter by MSCT including the mean of the long- and short-axis diameters, diameter derived from cross-sectional area, and diameter derived from the circumference were larger than the measurement by TTE and TTE (all P<0.05). (4) Implantation was successful in all patients.Moderate to severe paravalvular leakage was detected in 3 patients at 7 days post TAVI, and 1 patient developed severe prosthetic valve restenosis at 6 months post TAVI and received valve-in-valve implantation. Conclusions: In severe aortic stenosis patients referred for TAVI, the aortic annular diameter derived from TTE and TEE measurements are smaller than that from MSCT.In the absence of a gold standard, selection of prosthetic valve type in TAVI procedure should rely on comprehensive considerations, which is of importance to get good clinical results for severe aortic stenosis patients underwent TAVI.

Epidemiological characteristics of the carriers with coexistence of HBsAg and anti-HBs based on a community cohort study.

The coexistence of HBsAg and anti-HBs is an atypical serological pattern in HBV infection. There is no epidemiological characteristics of this serological pattern in the community and there is controversy over the molecular mechanisms underlying this pattern. We investigated the epidemiological characteristics of the carriers with HBsAg and anti-HBs in a longitudinal community cohort study. The prevalence of this atypical serological pattern was 2.93% (122/4169) in HBsAg-positive populations. The prevalence progressively increased with age from 40 to 70 years old. The rate of HBeAg positive and detectable HBV DNA were both significantly higher in carriers with this pattern than in carriers who were HBsAg positive but anti-HBs negative (26/122 verse 598/4047, P = 0.046; 86/122 verse 275/529,P < 0.001). After 1 year of follow-up, 85.19% of the carriers still had coexistence HBsAg and anti-HBs, 14.81% of the carriers lost their anti-HBs. Viral sequencing showed that carriers with coexistence of HBsAg and anti-HBs had higher numbers of residue changes within the S gene than carriers who were HBsAg positive but anti-HBs negative (2.42 verse 1.33 changes per 100 residues, P < 0.05). Hence, the coexistence of HBsAg and anti-HBs is a unique serological pattern which may be associated with an increased risk of adverse clinical outcome and may be related to HBsAg immune variants which have genotypic heterogeneity.

TaALMT1 promoter sequence compositions, acid tolerance, and Al tolerance in wheat cultivars and landraces from Sichuan in China.

Previous genetic studies on wheat from various sources have indicated that aluminum (Al) tolerance may have originated independently in USA, Brazil, and China. Here, TaALMT1 promoter sequences of 92 landraces and cultivars from Sichuan, China, were sequenced. Five promoter types (I', II, III, IV, and V) were observed in 39 cultivars, and only three promoter types (I, II, and III) were observed in 53 landraces. Among the wheat collections worldwide, only the Chinese Spring (CS) landrace native to Sichuan, China, carried the TaALMT1 promoter type III. Besides CS, two other Sichuan-bred landraces and six cultivars with TaALMT1 promoter type III were identified in this study. In the phylogenetic tree constructed based on the TaALMT1 promoter sequences, type III formed a separate branch, which was supported by a high bootstrap value. It is likely that TaALMT1 promoter type III originated from Sichuan-bred wheat landraces of China. In addition, the landraces with promoter type I showed the lowest Al tolerance among all landraces and cultivars. Furthermore, the cultivars with promoter type IV showed better Al tolerance than landraces with promoter type II. A comparison of acid tolerance and Al tolerance between cultivars and landraces showed that the landraces had better acid tolerance than the cultivars, whereas the cultivars showed better Al tolerance than the landraces. Moreover, significant difference in Al tolerance was also observed between the cultivars raised by the National Ministry of Agriculture and by Sichuan Province. Among the landraces from different regions, those from the East showed better acid tolerance and Al tolerance than those from the South and West of Sichuan. Additional Al-tolerant and acid-tolerant wheat lines were also identified.

Ultrafast-laser-induced backward stimulated Raman scattering for tracing atmospheric gases.

By combining tunable broadband pulse generation with the technique of nonlinear spectral compression we demonstrate a prototype scheme for highly selective detection of air molecules by backward stimulated Raman scattering. The experimental results allow to extrapolate the laser parameters required for standoff sensing based on the recently demonstrated backward atmospheric lasing.

Observations of ionospheric electron beams in the plasma sheet.

Electrons streaming along the magnetic field direction are frequently observed in the plasma sheet of Earth's geomagnetic tail. The impact of these field-aligned electrons on the dynamics of the geomagnetic tail is however not well understood. Here we report the first detection of field-aligned electrons with fluxes increasing at ~1 keV forming a "cool" beam just prior to the dissipation of energy in the current sheet. These field-aligned beams at ~15 R(E) in the plasma sheet are nearly identical to those commonly observed at auroral altitudes, suggesting the beams are auroral electrons accelerated upward by electric fields parallel (E([parallel])) to the geomagnetic field. The density of the beams relative to the ambient electron density is δn(b)/n(e)~5-13% and the current carried by the beams is ~10(-8)-10(-7) A m(-2). These beams in high ß plasmas with large density and temperature gradients appear to satisfy the Bohm criteria to initiate current driven instabilities.