基于三维测距和LS-LM的传感器网络节点定位研究（英文）

为了有效提高无线传感网中三维测距节点定位的精确度,提出了一种基于三维测距和LS-LM的无线传感网节点定位算法。首先,运用了海伦公式的四面体体积公式,结合平面上向量旋转2维变换,在仅需要3个锚节点的情况下就能够得到估计距离和方向。其次,针对锚节点数量大于3的情况,利用Least-Square Levenberg-Marquardt (LS-LM)算法对目标节点的估计位置进行了优化。实验验证了提出算法在无线传感器网三维定位的可行性。仿真结果表明:与传统的3维LM和类似算法相比,提出算法的性能更好,定位精度提高了约8%。

Color-related chlorophyll and carotenoid concentrations of Chinese kale can be altered through CRISPR/Cas9 targeted editing of the carotenoid isomerase gene BoaCRTISO

The carotenoid isomerase gene(BoaCRTISO)of Chinese kale was targeted and edited using the CRISPR/Cas9 system in the present study.The results showed a high mutation rate(81.25%),and 13 crtiso mutants were obtained.Only two types of mutations,insertions and replacements,were found.Both the total and individual carotenoid and chlorophyll concentrations of the biallelic and homozygous mutants were reduced,and the total levels declined by 11.89–36.33%.The color of the biallelic and homozygous mutants changed from green to yellow,likely reflecting a reduction in the color-masking effect of chlorophyll on carotenoids.The expression levels of most carotenoid and chlorophyll biosynthesis-related genes,including CRTISO,were notably lower in the mutants than in the WT plants.In addition,the functional differences between members of this gene family were discussed.In summary,these findings indicate that CRISPR/Cas9 is a promising technique for the quality improvement of Chinese kale and other Brassica vegetables.

Spatial heterogeneity of fine root biomass of Pinus massoniana forests in the Three Gorges Reservoir Area, China

Environmental heterogeneity is a constant presence in the natural world that significantly affects plant behavior at a variety of levels of complexity. In order to estimate the spatial pattern of fine root biomass in the Three Gorges Reservoir Area, the spatial heterogeneity of fine root biomass in the upper layer of soils (0-10 cm) in three Masson pine (Pinus massoniana) stands in the Three Gorges Reservoir Area, China, was studied in 30 m × 30 m plots with geostatistical analysis. The results indicate that 1) both the live and dead fine root biomass of stand 2 were less than those of other stands, 2) the spatial variation of fine roots in the three stands was caused together by structural and random factors with moderate spatial dependence and 3) the magnitude of spatial heterogeneity of live fine roots ranked as: stand 3 > stand 1 > stand 2, while that of dead fine roots was similar in the three stands. These findings suggested that the range of spatial autocorrelation for fine root biomass varied considerably in the Three Gorges Reservoir Area, while soil properties, such as soil bulk density, organic matter and total nitrogen, may exhibit great effect on the spatial distribution of fine roots. Finally, we express our hope to be able to carry out further research on the quantitative relationship between the spatial heterogeneous patterns of plant and soil properties.

Co-infection of SARS-COV-2 and Influenza A Virus:A Case Series and Fast Review

Coronavirus disease 2019(COVID-19)occurs in the influenza season and has become a global pandemic.The present study aimed to examine severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)co-infection with influenza A virus(IAV)in an attempt to provide clues for the antiviral interventions of co-infected patients.We described two patients who were co-infected with SARS-CoV-2 and IAV treated at Wuhan Union Hospital,China.In addition,we performed a review in PubMed,Web of Science and CNKI(from January 1 up to November 1,2020)with combinations of the following key words:“COVID-19,SARS-COV-2,influenza A and co-infection”.A total of 28 co-infected patients were enrolled in the analysis.Of the 28 patients,the median age was 54.5 years(IQR,34.25–67.5)and 14 cases(50.0%)were classified as severe types.The most common symptoms were fever(85.71%),cough(82.14%)and dyspnea(60.71%).Sixteen patients had lymphocytopenia on admission and 23 patients exhibited abnormal radiological changes.The median time from symptom onset to hospital admission was 4 days(IQR,3–6),and the median time of hospital stay was 14 days(IQR,8.5–16.75).In conclusion,patients with SARSCOV-2 and IAV co-infection were similar to those infected with SARS-COV-2 alone in symptoms and radiological images.SARS-COV-2 co-infection with IAV could lead to more severe clinical condition but did not experience longer hospital stay compared with patients infected with SARSCOV-2 alone.

Optimal activated carbon for separation of CO_2 from(H_2 + CO_2) gas mixture

Seven types of activated carbon were used to investigate the effect of their structure on separation of CO_2 from(H_2 + CO_2) gas mixture by the adsorption method at ambient temperature and higher pressures. The results showed that the limiting factors for separation of CO_2 from 53.6 mol% H_2 + 46.4 mol% CO_2 mixture and from 85.1 mol% H_2 + 14.9 mol% CO_2 mixture were different at 20 °C and about 2 MPa. The best separation result could be achieved when the pore diameter of the activated carbon ranged from 0.77 to 1.20 nm, and the median particle size was about2.07 lm for 53.6 mol% H_2 + 46.4 mol% CO_2 mixture and 1.41 lm for 85.1 mol% H_2 + 14.9 mol% CO_2 mixture. The effect of specific area and pore diameter of activated carbon on separation CO_2 from 53.6 mol% H_2 + 46.4 mol% CO_2 mixture was more significant than that from 85.1 mol% H_2 + 14.9 mol% CO_2 mixture. CO_2 in the gas phase can be decreased from 46.4 mol% to 2.3 mol%–4.3 mol% with a two-stage separation process.

大型高效离心通风机支撑管优化设计

为研究支撑管对大型高效离心通风机性能的影响,优化支撑管布局,以某新型高效离心通风机为研究对象,将通风机全压、效率及蜗壳内部全压损失和安全性做为评价指标,开展了针对风机蜗壳内支撑管直径、数量和布置位置的优化设计。研究结果表明,机壳支撑管数量越多,管径越大,蜗壳内压力损失就越大,风机整机效率会越低;支撑管的布置位置不合理,也会增加机壳内部流动损失,降低风机的整机效率。在保证风机安全运行的前提下,用数值模拟优化支撑结构布局后,该风机效率增加了3.55%。

Prolonged SARS-CoV-2 Viral Shedding in Patients with COVID-19 was Associated with Delayed Initiation of Arbidol Treatment and Consulting Doctor Later: A Retrospective Cohort Study

Objective:To study data about SARS-CoV-2 virus shedding and clarify the risk factors for prolonged virus shedding.Methods:Data were retrospectively collected from adults hospitalized with laboratory-confirmed coronavirus disease-19(COVID-19)in Wuhan Union Hospital.We compared clinical features among patients with prolonged(a positive SARS-CoV-2 RNA on day 23 after illness onset)and short virus shedding and evaluated risk factors associated with prolonged virus shedding by multivariate regression analysis.Results:Among 238 patients,the median age was 55.5 years,57.1%were female,92.9%(221/238)were administered with arbidol,58.4%(139/238)were given arbidol in combination with interferon.The median duration of SARS-CoV-2 virus shedding was 23 days(IQR,17.8-30 days)with a longest one of 51 days.The patients with prolonged virus shedding had higher value of D-dimer(P=0.002),IL-6(P<0.001),CRP(P=0.005)and more lobes lung lesion(P=0.014)on admission,as well as older age(P=0.017)and more patients with hypertension(P=0.044)than in those the virus shedding less than 23 days.Multivariate regression analysis revealed that prolonged viral shedding was significantly associated with initiation arbidol≥8 days after symptom onset[OR:2.447,95%CI(1.351-4.431)],≥3 days from onset of symptoms to first medical visitation[OR:1.880,95%CI(1.035-3.416)],illness onset before Jan.31,2020[OR:3.289,95%CI(1.474-7.337)].Arbidol in combination with interferon was also significantly associated with shorter virus shedding[OR:0.363,95%CI(0.191-0.690)].Conclusion:Duration of SARS-CoV-2 virus shedding was long.Early initiation of arbidol and arbidol in combination with interferon as well as consulting doctor timely after illness onset were helpful for SARS-CoV-2 clearance.

Spreading of extended-spectrum β-lactamase-producing Escherichia coli ST131 and Klebsiella pneumoniae ST11 in patients with pneumonia a molecular epidemiological study

Background: Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) are the important pathogens causing pneumonia. This study aimed to investigate the clinical characteristics and molecular epidemiology of ESBL-producing E. coli and K. pneumoniae causing pneumonia at a large teaching hospital in China. Methods: We collected patient's clinical data and ESBL-producing E. coli and K. pneumoniae strains causing pneumonia (from December 2015 to June 2016) at a hospital in Wuhan. The susceptibilities, multi-locus sequence typing, homologous analysis, ESBL genes by polymerase chain reaction and sequencing were determined. Results: A total of 59 ESBL-producing strains (31 E. coli and 28 K. pneumoniae) isolated from patients with pneumonia were analyzed. The majority of strains were isolated from patients were with hospital-acquired pneumonia (37/59, 62.7%), followed by community-acquired pneumonia (13/59, 22.0%), and ventilator-related pneumonia (9/59, 15.3%). The E. coli ST131 (9 isolates, 29.0%) and K. pneumoniae ST11 (5 isolates, 17.9%) were the predominant sub-types. The most prevalent ESBL gene was CTX-M-14, followed by SHV-77, CTX-M-3, SHV-11, and CTX-M-27. At least 33 (55.9%) of the ESBL-producing strains carried two or more ESBL genes. The ISEcp1 and IS26 were found upstream of all blaCTX-M (CTX-Ms) and of most blaSHV (SHVs)(57.6%), respectively. Moreover, three ESBL-producing K. pneumoniae ST11 strains which were resistant to carbapenems carried the blaNDM-1 and blaKPC-2, two of which also bearing blaOXA-48 were resistant to all antibiotics (including Tigecycline). Conclusions: Hospital-acquired pneumonia is more likely correlated with ESBL-producing E. coli and K. pneumoniae. ESBL-producing E. coli ST131 and multi-drug resistance ESBL-producing, as well as New Delhi metallo-β-lactamase-1 (NDM-1) and Klebsiella pneumoniae carbapenemases-2 (KPC-2) bearing K. pneumoniae ST11 are spreading in patients with pneumonia in hospital.

Clinical features and risk factors associated with severe COVID-19 patients in China

Background::Coronavirus disease 2019(COVID-19),which is caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),has rapidly spread throughout the world.In this study,we aimed to identify the risk factors for severe COVID-19 to improve treatment guidelines.Methods::A multicenter,cross-sectional study was conducted on 313 patients hospitalized with COVID-19.Patients were classified into two groups based on disease severity(nonsevere and severe)according to initial clinical presentation.Laboratory test results and epidemiological and clinical characteristics were analyzed using descriptive statistics.Univariate and multivariate logistic regression models were used to detect potential risk factors associated with severe COVID-19.Results::A total of 289 patients(197 nonsevere and 92 severe cases)with a median age of 45.0(33.0,61.0)years were included in this study,and 53.3%(154/289)were male.Fever(192/286,67.1%)and cough(170/289,58.8%)were commonly observed,followed by sore throat(49/289,17.0%).Multivariate logistic regression analysis suggested that patients who were aged≥65 years(OR:2.725,95%confidence interval[CI]:1.317-5.636;P=0.007),were male(OR:1.878,95%CI:1.002-3.520,P=0.049),had comorbid diabetes(OR:3.314,95%CI:1.126-9.758,P=0.030),cough(OR:3.427,95%CI:1.752-6.706,P<0.001),and/or diarrhea(OR:2.629,95%CI:1.109-6.231,P=0.028)on admission had a higher risk of severe disease.Moreover,stratification analysis indicated that male patients with diabetes were more likely to have severe COVID-19(71.4%vs.28.6%,χ2=8.183,P=0.004).Conclusions::The clinical characteristics of those with severe and nonsevere COVID-19 were significantly different.The elderly,male patients with COVID-19,diabetes,and presenting with cough and/or diarrhea on admission may require close monitoring to prevent deterioration.

Radiological features of traumatic vertebral endplate fracture:an analysis of 194 cases with 263 vertebral fractures

Background:The importance of identifying osteoporotic vertebral endplate or/and cortex fracture(ECF),which primarily includes endplate fracture(EPF)and vertebral anterior cortex buckling,has been recognized.However,some old traumatic ECFs with healing process in the elderly may be mistaken as osteoporotic.This study analyzes the radiological features of traumatic EPF.Methods:This was a retrospective analysis of 194 spine trauma patients with 263 vertebral fractures(mean age:42.11±9.82 years,118 males and 76 females).All patients had traumatic EPF identified by X-ray/CT/MRI.Results:The involved vertebra was mostly L1(29.7%),followed by T12 and L2.Except EPFs involved both superior and inferior endplates(12.6%),only 1.9%involved inferior endplate alone,with the majority involved superior endplate.If each endplate was divided into five segments of equal lengths(from anterior to posterior:a1,a2,m,p2,p1),the most depressed point of superior EPFs was mostly at segment-a2(approximately 45%),followed by segment-a1(approximately 20%)or segment-m(approximately 20%),and very rarely at segment-p1.The upper 1/3 of anterior vertebral wall was more likely to fracture,followed by middle 1/3 of anterior wall.For posterior vertebral wall fracture,68.5%broke the bony wall surrounding the basivertebral vain.58.6%,30.0%,and 11.4%of vertebral fractures had<1/5,1/5-1/3,and>1/3 vertebral body height loss.As the extent of vertebral height loss increased,the chance of having both superior and inferior EPFs also increased;however,the chance of having inferior EPF alone did not increase.Conclusion:Traumatic EPF features are characterized,which may help the differentiation of traumatic and osteoporotic EPFs.