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Objective@#To investigate the prevalence of flat feet and associated factors in school aged children in Kunming City, to provide evidence supporting the prevention of flat feet.@*Methods@#From December 2021 to February 2022, 4 444 children aged 7-13 in five primary schools in Kunming were screened for flat feet with the optical foot assessment and recording device. The incidence of flatfoot was counted, and Logistic regression was used to analyze the influencing factors of flatoccurrence.@*Results@#The overall prevalence rate was 29.10%, of which 21.79% were mild, 52.43% were moderate, 25.78% were severe, 89.10 % were bipedal, and 10.90% were monopedal. The prevalence rates in the 7-year old and 13-year old groups were 36.91% and 10.43%, respectively, and the risk in the former was 5.00 times that in the latter( OR=5.00, 95%CI =3.22-7.52). The prevalence rates in rural and urban students were 38.53%, 22.46%, respectively, and the risk in the former was 2.17 times that in the latter( OR=2.17, 95%CI =1.90-2.47). The prevalence of flat feet in male and female students were 34.21%, 23.29%, respectively, and the risk in male students was 1.71 times higher than that in female students( OR=1.71, 95%CI =1.50-1.95). The incidence of flat feet correlated with BMI, and the risk of flat feet was higher in the group with overweight and obese groups than normal( OR=1.31, 1.10, P < 0.01). @*Conclusion@#The prevalence of flat feet in school age children aged 7-13 years decreased with age. The prevalence and risk of flat feet is lower in girls than boys, and the incidence and risk of flat feet are lower in urban than rural children. The incidence of flat feet in most children is moderate, and the risk increased with increasing BMI. For school aged children with flat feet, early prevention, detection and treatment are needed.
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BACKGROUNDThe outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly spread globally. The laboratory diagnosis of SARS-CoV-2 infection has relied on nucleic acid tests. However, there are many limitations of nucleic acid tests, including low throughput and high rates of false negatives. More sensitive and accurate tests to effectively identify infected patients are needed. METHODSThis study has developed fully automated chemiluminescent immunoassays (CLIA) to determine IgM and IgG antibodies to SARS-CoV-2 in human serum. The assay performance has been evaluated at 10 hospitals. Clinical specificity was evaluated by measuring 972 hospitalized patients with diseases other than COVID-19, and 586 donors of a normal population. Clinical sensitivity was assessed on 503 confirmed cases of SARS-CoV-2 by RT-PCR and 52 suspected cases. RESULTSThe assays demonstrated satisfied assay precision with coefficient of variation (CV) of less than 4.45%. Inactivation of specimen does not affect assay measurement. SARS-CoV-2 IgM shows clinical specificity of 97.33% and 99.49% for hospitalized patients and normal population respectively. SARS-CoV-2 IgG shows clinical specificity of 97.43% and 99.15% for the hospitalized patients and the normal population respectively. SARS-CoV-2 IgM and IgG show clinical sensitivity of 85.88% and 96.62% respectively for confirmed SARS-Cov-2 infection with RT-PCR, of 73.08% and 86.54% respectively for suspected cases. CONCLUSIONSwe have developed fully automated immunoassays for detecting SARS-CoV-2 IgM and IgG antibodies in human serum. The assays demonstrated high clinical specificity and sensitivity, and add great value to nucleic acid testing in fighting against the global pandemic of the SARS-CoV-2 infection.
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Objective To validate the analytical performance of a cardiac troponin I(cTnI)assay AccuTnI+3 on chemiluminescnet analyzer DXI800 and Access2;and to establish the 99th percentile of cTnI in an apparently healthy Chinese population.Methods The subjects are composed of 1 369 apparently healthy people and 20 acute myocardial infarction(AMI)patients from Wuhan Asian Heart Hospital and Fuwai Hospital from October 2014 to June 2015.The healthy people include 680 males and 689 females;with 340 subjects aged 18-30,674 subjects aged 31-64, and 355 subjects aged ≥65.The detection limits and imprecision of AccuTnI +3 assays were validated according to CLSI EP 15-A2 and EP17-A2 documents;the same samples were analyzed on DXI800 and Access2 to assess the consistency between the two analyzers using Bland Altman plot and Passing-Bablok regression.The correlation between different sample types (lithium heparin plasma, EDTA plasma & serum)were assessed using linear regression analysis.The lithium heparin plasmasamples from 1 369 apparently healthy people were analyzed to calculate the 99th percentile of cTnI.The cTnI concentrations were compared among age and sex groups.The 99th percentile of cTnI were also calculated for each group.The detection rate of cTnI in apparently healthy people was calculated using SPSS23.0.Results The limit of blank(LoB), limit of detection(LoD), and limit of quantification(LoQ)where CV%=10% were 0.007 ng/ml,0.010 ng/ml and 0.016 ng/ml on DXI800;0.008 ng/ml,0.012 ng/ml and 0.026 ng/ml on Access2,respectively.The cTnI measurements on DXI800 and Access2 were consistent and comparable.The cTnI concentrations of lithium heparin plasma, EDTA plasma and serum samples were linearly correlated pairwise: EDTA plasma measuremen t =0.76 heparin plasma measurement, R2=0.999(n=40, P<0.001); serum measuremen t =1.05 heparin plasma measurement,R2=0.996(n=40,P<0.001); serum measuremen t=1.38 EDTA plasma measurement, R2=0.993(n=40,P<0.001).The 99th percentiles were 0.030 ng/ml and 0.035 ng/ml on DXI800 and Access2,respectively,from 1 369 apparently healthy Chinese people.cTnI is significantly higher in elder group than in younger group.The 99th percentiles in 18-30 years old group,31-64 years old group,and≥65 years old group are:0.011 ng/ml,0.029 ng/ml,and 0.035 ng/ml respectively for DXI800;0.023 ng/ml,0.034 ng/ml, and 0.045 ng/ml respectively for Access2.cTnI is significantly higher in men than in women.The 99th percentiles in men and women are: 0.034 ng/ml and 0.032 ng/ml respectively for DXI800;0.043 ng/ml and 0.031 ng/ml respectively for Access2.cTnI was measurable in 62%and 87%of healthy subjects on DXI800 and Access2 systems,respectively.Conclusions The analytical performance of AccuTnI+3 assay fulfills the need of clinical use and the criteria of high-sensitive cardiac troponin assay.
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The combination effect of multiwavelength active coherent beam combination (CBC) is investigated theoretically. The dependence of the combination effect on the optical path control precision, spectral width, wavelength number, and channel number is revealed. In the case of small optical path variance, the combination effect approximately decreases in quadratic form with wavelength number N, spectral width Δν, and optical path variance σ increasing. In the case of large optical path variance, the combination effect is independent of the optical path variance and the spectral width. The larger the wavelength number is, the smaller the Strehl ratio expectation is, and it finally degenerates to the incoherent combination. The necessity of optical path control is discussed. This study is helpful for multiwavelength CBC system design and the combination effect estimation.
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Objective To evaluate the performance of Beckman Coulter Enhanced troponin Ⅰ immunoassay system (including the limit of detection and total imprecision) and establish the 99th percentile of Enhanced troponin Ⅰ in apparently healthy Chinese people in Kunming and Wuhan.Methods Evaluated the limit of detection and total imprecision of Beckman Enhanced troponin Ⅰ according to protocols EP of Clinical Laboratory Standards Institute; chose apparently healthy people from Wuhan (average altitude of 27 m) which represents plain regions,and Kunming (average altitude of 1895 m) which represents plateau regions.760 subjects from Wuhan were selected,aging from 30 to 91,included 400 males and 360 females.A total of 192 subjects from Kunming were selected,aging from 30 and 77,60 patients,which included 60 male and 132 female cases.To calculate the 99th percentile of Enhanced troponin Ⅰ by region,age,and gender.Results The limit of detection of Beckman Enhanced troponin Ⅰ is 0.013 μg/L,the cTnI concentration is 0.025 μg/L at 10％ CV.The 99th percentile of Enhanced troponin Ⅰ of the total population in Wuhan is 0.036 μg/L,the 99th percentile of men and women are 0.038 μg/L and 0.035 μg/L respectively,the 99th percentile in the 30-69 years group and over 70 years group are 0.038 μg/L and 0.035 μg/L respectively.The 99th percentile of Enhanced troponin Ⅰ of the total population in Kunming is 0.040 μg/L.To keep the 2nd digit after decimal point for results from Wuhan and Kunming,the 99th percentile of Enhanced troponin Ⅰ of the apparently healthy Chinese in 0.04 μg/L,where the CV is 8.23％.The percentage of positive samples detected below the 99th percentile in the normal reference population in Wuhan is 94％.Conclusions The 99th percentile of Beckman Enhanced troponin Ⅰ of the Chinese apparently healthy people is 0.04 μg/L,where the total imprecision is 8.23％,and the detection performance reach the acceptable levels per the guideline.
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Objective To evaluate the interference of ALP on cTnI assays. Methods One normal mixed plasma sample and 2 abnormal mixed plasma samples with different cTnI levels were prepared, and then divided them into 8 groups respectively. One group was randomly chosen as control while different amounts of ALP were added into the other seven groups. The concentrations of cTnI and ALP in each plasma portion were detected by ACCESS2 (Beckman-Coulter, Inc ) and AXSYM (Abbott Laboratories )separately. The results of the seven tested groups were then compared with those of the control, so as to evaluate whether ALP could interfere with the cTnI assay. Results When the chemiluminescent Access cTnI assay was carried out for detection of normal plasma, the concentration of ALP was up to 3 716 U/L and did not interfere with the test results of cTnI [(0. 04 ±0.01) μg/L] compared with those of the control portion [(0. 04 ± 0. 01 ) μg/L] (t = 0. 40, P ＞ 0. 05 ). Once the concentration of ALP went beyond 917 U/L, the AXSYM cTnI assay results [( 0.08 ± 0. 01 ) μg/L] were higher than those of the normal control ( t =-4. 89, P＜0. 01 ); When the concentration of ALP was up to 3 534 U/L, the test results of abnormal plasma cTnI detected by the Access assay [( 13.41 ±0. 17) μg/L] did not show significant differences from those of the control [(13.48±0.16) μg/L] (t=0. 52,P＞0.05).Conclusions High concentration ofALP did not interfere with the Access cTnI assay or lead to false positive results. However, the high level of ALP( ＞ 917 U/L) could interfere with the AXSYM cTnI assay and cause a false positive result.
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In this paper we determine the optimum propagation distance between measurement planes and the plane of the lens in a wavefront curvature sensor with the diffraction optics approach. From the diffraction viewpoint, the measured wavefront aberration can be decomposed into Fourier harmonics at various frequencies. The curvature signal produced by a single harmonic is analyzed with the wave propagation transfer function approach, which is the frequency analysis of wavefront curvature sensing. The intensity of the curvature signal is a sine function of the product of the propagation distance and the squared frequency. To maximize the curvature signal, the optimum propagation distance is proposed as one quarter of the Talbot length at the critical frequency (average power point at which the power spectrum density is the average power spectrum density). Following the determination of the propagation distance, the intensity of the curvature signal varies sinusoidally with the squared frequencies, vanishing at some higher frequency bands just like a comb filter. To cover these insensitive bands, wavefront curvature sensing with dual propagation distances or with multi-propagation distances is proposed.
