In order to solve the problems of difficult test, high cost and long cycle in the development of large-scale airborne negative pressure isolation system, the simulation analysis of negative pressure response characteristics is carried out around various aviation conditions such as aircraft ascending, leveling and descending, especially rapid decompression, based on the computational fluid dynamics (CFD) method. The results showed that the isolation cabin could achieve -50 Pa pressure difference environment and form a certain pressure gradient. The exhaust air volume reached the maximum value in the early stage of the aircraft's ascent, and gradually decreased with the increase of altitude until it was level flying. In the process of aircraft descent, the exhaust fan could theoretically maintain a pressure difference far below -50 Pa without working; Under the special condition of rapid pressure loss, it was difficult to deal with the rapid change of low pressure only by the exhaust fan, so it was necessary to design safety valve and other anti-leakage measures in the isolation cabin structure. Therefore, the initial stage of aircraft ascent is the key stage for the adjustment and control of the negative pressure isolation system. By controlling the exhaust air volume and adjusting parameters, it can adapt to the change of low pressure under normal flight conditions, form a relatively stable negative pressure environment, and meet the needs of biological control, isolation and transport.
Aircraft ; Computer Simulation ; Aviation/instrumentation* ; Humans ; Hydrodynamics ; Air Pressure ; Equipment Design ; Pressure

Objective:To establish 30-day of age transcutaneous bilirubin (TcB) reference curves for healthy neonates, and to investigate regional variations in bilirubin dynamics.Methods:A multicenter retrospective cohort study was conducted. A total of 220 950 healthy neonates born at a gestational age of 35-<42 weeks, with a birth weight ≥2 000 g, who did not receive phototherapy within 60 h after birth were recruited. All of them underwent remote TcB monitoring using the Bilibaby remote jaundice monitoring system between August 1 st, 2020 and December 31 st, 2024 in 426 hospitals. TcB data were collected within the period from birth to 30-day of age. The P40, P75, and P95 of TcB values were calculated, and dynamic TcB curves for 30-day of age were constructed. Patterns of bilirubin change, rates of change, and transition outcomes were described. Regional comparisons between South and North were conducted using linear mixed-effects models for TcB trajectories and Pearson′s chi-square test for outcome differences. Results:A total of 220 950 neonates were included, of whom 101 711 (46.03%) were female. Gestational age at birth was (38.75±1.12) weeks, and birth weight was (3 272±417) g. TcB levels increased rapidly within 3-day of age, peaked at 4-6-day of age, with peak values at P40, P75, and P95 of 200.6, 239.7 and 275.4 μmol/L (11.8, 14.1 and 16.2 mg/dl), respectively. TcB levels gradually declined thereafter and stabilized after 13-day of age, with values at P40, P75, and P95 fluctuating between 147.9-159.8, 190.4-200.6, and 231.2-239.7 μmol/L (8.7-9.4, 11.2-11.8, 13.6-14.1 mg/dl), respectively. Notably, among neonates categorized as low-or low-intermediate-risk within 3-day of age, 6 700 (12.76%) progressed to intermediate-high or high risk between 4 and 30 days of age. Before 13-day of age, TcB levels in the southern regions were consistently higher than those in the northern regions ( P=0.039); from 14 to 30 days of age, the overall TcB levels had no statistically difference, but the temporal changes in TcB still showed regional differences (degrees of freedom=3, all interaction P<0.05). Among neonates classified as low-or low-intermediate risk within 3-day of age, 25 326 were from southern regions, of whom 4 254 (16.80%) progressed to intermediate-high or high risk between 4 and 30 days of age. In northern regions, 27 193 neonates were classified as low-or low-intermediate risk within 3-day of age, among whom 2 446 (8.99%) progressed to intermediate-high or high risk. The risk progression between the 2 regions had statistically difference ( χ2=716.49, P<0.001). Conclusions:A TcB percentile curve for neonates within 30-day of age was established, revealing that both the overall TcB level and its temporal trend were higher in southern than in northern newborns. These findings provide baseline data to support continuous management of neonatal jaundice.

Objective:To analyze the quality level of maternal mid-trimester serum prenatal screening in China from 2019 to 2023.Methods:A questionnaire survey was conducted to collect information from laboratories participating in the National Health Commission′s Clinical Laboratory Center inter-laboratory quality assessment program for prenatal screening from 2019 to 2023. The collected data included screening protocols, detection methods, testing systems, and monthly laboratory screening quality indicators. The Chi-square test was used to compare the initial screening positive rates among different screening protocols, provinces, detection methods, and testing systems. A log-transformed linear regression analysis was performed to evaluate the relationship between the average annual sample size and the out-of-control rate of various median multiple of the median (mMoM) values.Results:This study included 806 laboratories from 29 provinces (including autonomous regions and municipalities). The five-year average out-of-control rates for mMoM values across indicators ranged from 15.8% to 31.3%. The initial positive rates of dual, triple, and quadruple screening protocols were statistically different ( χ2=760.2, P<0.001). The initial positive rates across different provinces ranged from 4.7% to 10.3%, with statistically significant differences ( χ2=35 388.0, P<0.001). There were also statistically significant differences in initial positive rates between different testing systems ( χ2=2 493.2, P<0.001). Testing systems using chemiluminescence methods had significantly higher initial positive rates compared to systems using time-resolved fluorescence methods (7.2% vs. 6.5%, χ2=533.6, P<0.001). Log-linear regression analysis showed that testing systems with larger annual average sample sizes had lower out-of-control rates for mMoM values (AFP: β=-0.100, P=0.005; hCG: β=-0.123, P=0.008; uE3: β=-0.139, P=0.007). Conclusion:There are significant differences in the quality of maternal mid-trimester serum screening across different detection methods, testing systems and provinces in China.

Objective:To investigate the current status of preimplantation genetic testing for aneuploidies (PGT-A) in China in 2024 and to provide recommendations for ensuring the consistency of PGT-A results.Methods:This study was a nationwide external quality assessment research. The National Center for Clinical Laboratories of the National Health Commission conducted two surveys in June and December 2024, with participation from 31 laboratories across China. During each survey, quality control samples of varying concentrations were distributed: the first survey distributed 6 samples (Batch Nos. 202401-202406) and the second survey distributed 3 samples (Batch Nos. 202431-202433). Participating laboratories were required to submit information including detection platforms, single-cell amplification methods, library construction methods, sequencing instruments, and test results. Collected data were statistically analyzed using Microsoft Excel to evaluate laboratories' PGT-A testing capabilities and determine whether results met predefined quality control requirements.Results:All 31 laboratories submitted results for both surveys. In the first survey, 90.3% (28/31) met qualification criteria with a 9.7% failure rate (3/31). For individual batches, pass rates were 90.3% (28/31) for batches 202401-202403 and 100% (31/31) for batches 202404-202406. The second survey achieved 100% (31/31) compliance across all three batches (202431-202433), with each batch maintaining a 100% pass rate.Conclusion:The detection quality of PGT-A in China is generally good, but with differences, and factors such as sample concentration, transportation conditions and detection methods affect the consistency of the results. The study highlights the urgent need for nationwide external quality assessment of PGT-A in China. This will help identify issues in laboratories in a timely manner and ensure the consistency of PGT-A test results.

Objective:To analyze the quality level of maternal mid-trimester serum prenatal screening in China from 2019 to 2023.Methods:A questionnaire survey was conducted to collect information from laboratories participating in the National Health Commission′s Clinical Laboratory Center inter-laboratory quality assessment program for prenatal screening from 2019 to 2023. The collected data included screening protocols, detection methods, testing systems, and monthly laboratory screening quality indicators. The Chi-square test was used to compare the initial screening positive rates among different screening protocols, provinces, detection methods, and testing systems. A log-transformed linear regression analysis was performed to evaluate the relationship between the average annual sample size and the out-of-control rate of various median multiple of the median (mMoM) values.Results:This study included 806 laboratories from 29 provinces (including autonomous regions and municipalities). The five-year average out-of-control rates for mMoM values across indicators ranged from 15.8% to 31.3%. The initial positive rates of dual, triple, and quadruple screening protocols were statistically different ( χ2=760.2, P<0.001). The initial positive rates across different provinces ranged from 4.7% to 10.3%, with statistically significant differences ( χ2=35 388.0, P<0.001). There were also statistically significant differences in initial positive rates between different testing systems ( χ2=2 493.2, P<0.001). Testing systems using chemiluminescence methods had significantly higher initial positive rates compared to systems using time-resolved fluorescence methods (7.2% vs. 6.5%, χ2=533.6, P<0.001). Log-linear regression analysis showed that testing systems with larger annual average sample sizes had lower out-of-control rates for mMoM values (AFP: β=-0.100, P=0.005; hCG: β=-0.123, P=0.008; uE3: β=-0.139, P=0.007). Conclusion:There are significant differences in the quality of maternal mid-trimester serum screening across different detection methods, testing systems and provinces in China.

Objective:To investigate the current status of preimplantation genetic testing for aneuploidies (PGT-A) in China in 2024 and to provide recommendations for ensuring the consistency of PGT-A results.Methods:This study was a nationwide external quality assessment research. The National Center for Clinical Laboratories of the National Health Commission conducted two surveys in June and December 2024, with participation from 31 laboratories across China. During each survey, quality control samples of varying concentrations were distributed: the first survey distributed 6 samples (Batch Nos. 202401-202406) and the second survey distributed 3 samples (Batch Nos. 202431-202433). Participating laboratories were required to submit information including detection platforms, single-cell amplification methods, library construction methods, sequencing instruments, and test results. Collected data were statistically analyzed using Microsoft Excel to evaluate laboratories' PGT-A testing capabilities and determine whether results met predefined quality control requirements.Results:All 31 laboratories submitted results for both surveys. In the first survey, 90.3% (28/31) met qualification criteria with a 9.7% failure rate (3/31). For individual batches, pass rates were 90.3% (28/31) for batches 202401-202403 and 100% (31/31) for batches 202404-202406. The second survey achieved 100% (31/31) compliance across all three batches (202431-202433), with each batch maintaining a 100% pass rate.Conclusion:The detection quality of PGT-A in China is generally good, but with differences, and factors such as sample concentration, transportation conditions and detection methods affect the consistency of the results. The study highlights the urgent need for nationwide external quality assessment of PGT-A in China. This will help identify issues in laboratories in a timely manner and ensure the consistency of PGT-A test results.

Objective:To establish 30-day of age transcutaneous bilirubin (TcB) reference curves for healthy neonates, and to investigate regional variations in bilirubin dynamics.Methods:A multicenter retrospective cohort study was conducted. A total of 220 950 healthy neonates born at a gestational age of 35-<42 weeks, with a birth weight ≥2 000 g, who did not receive phototherapy within 60 h after birth were recruited. All of them underwent remote TcB monitoring using the Bilibaby remote jaundice monitoring system between August 1 st, 2020 and December 31 st, 2024 in 426 hospitals. TcB data were collected within the period from birth to 30-day of age. The P40, P75, and P95 of TcB values were calculated, and dynamic TcB curves for 30-day of age were constructed. Patterns of bilirubin change, rates of change, and transition outcomes were described. Regional comparisons between South and North were conducted using linear mixed-effects models for TcB trajectories and Pearson′s chi-square test for outcome differences. Results:A total of 220 950 neonates were included, of whom 101 711 (46.03%) were female. Gestational age at birth was (38.75±1.12) weeks, and birth weight was (3 272±417) g. TcB levels increased rapidly within 3-day of age, peaked at 4-6-day of age, with peak values at P40, P75, and P95 of 200.6, 239.7 and 275.4 μmol/L (11.8, 14.1 and 16.2 mg/dl), respectively. TcB levels gradually declined thereafter and stabilized after 13-day of age, with values at P40, P75, and P95 fluctuating between 147.9-159.8, 190.4-200.6, and 231.2-239.7 μmol/L (8.7-9.4, 11.2-11.8, 13.6-14.1 mg/dl), respectively. Notably, among neonates categorized as low-or low-intermediate-risk within 3-day of age, 6 700 (12.76%) progressed to intermediate-high or high risk between 4 and 30 days of age. Before 13-day of age, TcB levels in the southern regions were consistently higher than those in the northern regions ( P=0.039); from 14 to 30 days of age, the overall TcB levels had no statistically difference, but the temporal changes in TcB still showed regional differences (degrees of freedom=3, all interaction P<0.05). Among neonates classified as low-or low-intermediate risk within 3-day of age, 25 326 were from southern regions, of whom 4 254 (16.80%) progressed to intermediate-high or high risk between 4 and 30 days of age. In northern regions, 27 193 neonates were classified as low-or low-intermediate risk within 3-day of age, among whom 2 446 (8.99%) progressed to intermediate-high or high risk. The risk progression between the 2 regions had statistically difference ( χ2=716.49, P<0.001). Conclusions:A TcB percentile curve for neonates within 30-day of age was established, revealing that both the overall TcB level and its temporal trend were higher in southern than in northern newborns. These findings provide baseline data to support continuous management of neonatal jaundice.

Objective:To explore the relationship between preterm labor with different causes and cerebral perfusion in different regions of interest in very preterm infants.Methods:This was a prospective cohort study. A total of 145 preterm infants with gestational age of 28-31 +6 weeks who were hospitalized in the Neonatology Department of the Third Affiliated Hospital of Zhengzhou University within 24 h after birth from April 2022 to May 2023 were selected for the study, and were categorized into the iatrogenic preterm labor group ( n=55), spontaneous preterm labor with premature rupture of the membranes (PROM) group ( n=47), and spontaneous preterm labor with intact membranes group ( n=43) according to the cause of preterm labor. Cerebral blood flow (CBF) values in the cortex and deep gray matter of different regions of interest (frontal lobe, temporal lobe, parietal lobe, occipital lobe, thalamus, and basal ganglia) were measured using the arterial spin labeling technique in the very preterm infants in each group. One-way analysis of variance, Kruskal-Wallis H test and Bonferroni correction, Chi-square test or Fisher's exact probability method, analysis of covariance, and LSD test were used to compare the differences in CBF among the groups. Results:The differences in the incidence of complications such as cerebral white matter injury, Ⅰ-Ⅱ grade intracranial hemorrhage, and late-onset sepsis during hospitalization among the three groups of preterm infants were not statistically significant (all P>0.05). In the iatrogenic preterm labor group, compared with the spontaneous preterm labor with PROM group, CBF [in units of ml/ (100 g·min)] was higher in regions of interest such as the right temporal lobe [20.5 (16.1-24.6) vs. 17.1 (14.5-23.0)], bilateral parietal lobe [left side: 22.4 (17.1-25.3) vs. 16.9 (14.4-24.1); right side: 23.0 (18.2-27.4) vs. 17.0 (14.0-22.2)], right occipital lobe [22.1 (18.6-29.5) vs. 19.4 (13.7-24.5)], bilateral basal ganglia [left side: 33.0 (29.1-36.3) vs. 24.9 (22.9-33.1); right side: 32.8 (29.0-37.0) vs. 26.1 (22.3-35.0)], and bilateral thalamus [left side: 39.2 (36.0-45.0) vs. 32.6 (25.1-42.2); right side: 38.6 (34.6-44.1) vs. 32.0 (25.4-44.9)] (Bonferroni corrected, all P<0.017). Compared with the spontaneous preterm labor group with intact membranes, CBF in the iatrogenic preterm labor group was higher in the cortex and deep gray matter of regions of interest such as bilateral frontal lobe [left side: 21.4 (18.3-25.3) vs. 17.0 (12.0-22.2); right side: 22.1 (16.7-25.0) vs. 15.9 (12.0-23.3)], temporal lobe [left side: 21.4 (17.0-24.8) vs. 18.4 (14.0-22.0); right side: 20.5 (16.1-24.6) vs. 17.3 (13.3-22.3)], parietal lobe [left side: 22.4 (17.1-25.3) vs. 15.3 (10.4-20.8); right side: 23.0 (18.2-27.4) vs. 15.7 (11.1-23.6)], occipital lobe [left side: 22.7 (18.8-28.4) vs. 18.2 (11.4-23.4); right side: 22.1 (18.6-29.5) vs. 19.6 (14.0-25.8)], basal ganglia [left side: 33.0 (29.1-36.3) vs. 27.7 (19.1-32.4); right side: 32.8 (29.0-37.0) vs. 27.7 (21.5-33.0)] and thalamus [left side: 39.2 (36.0-45.0) vs. 33.9 (26.0-43.7); right side: 38.6 (34.6-44.1) vs. 33.3 (27.8-40.4)] (Bonferroni corrected, all P<0.017). Analysis of covariance revealed that the cause of preterm birth had a significant effect on CBF values in the cortex and deep gray matter of very preterm infants ( P=0.007), and that iatrogenic preterm birth elevated CBF perfusion in the localized cerebral cortex and deep gray matter of very preterm infants as compared to the spontaneous preterm births with PROM group and spontaneous preterm births with intact membranes group (LSD test, all P<0.05). Conclusion:Cerebral blood perfusion in very preterm infants is related to the causes leading to preterm birth, and local cortical and deep gray matter blood perfusion levels in the brain are increased in those with iatrogenic preterm birth compared to spontaneous preterm birth.

Objective:To evaluate the quality level of early pregnancy serum screening in China.Methods:Information on the coefficient of variation, bias, quality control (QC) rules, and testing methods from 576 laboratories participating in the 2022 early pregnancy serum screening inter-laboratory proficiency testing program by the National Health Commission Clinical Laboratory Center was collected. Serological screening indicators included free human chorionic gonadotropin β subunit (β-hCG), total β-hCG, and pregnancy-associated plasma protein A (PAPP-A). Six Sigma (σ) management was used to assess the quality level of the laboratories and the rationality of QC rules.Wilcoxon test was used to evaluate whether different testing time and methods affected the Sigma level.Results:A total of 119 laboratories tested total β-hCG, 457 laboratories tested free β-hCG, and 565 laboratories tested PAPP-A. Seventeen laboratories tested only one marker, 553 laboratories tested two markers, and six laboratories tested three markers. There was no statistically significant difference in sigma levels for the same analyte tested in May and September. The proportion of free β-hCG reaching 6σ was the highest at 71.9% (567/788); although total β-hCG had the lowest proportion reaching 6σ at 53.4% (103/193), it also had the lowest proportion below 3σ at 3.1% (6/193). Early pregnancy serum prenatal screening mainly involved five reagents and primarily used chemiluminescence and time-resolved fluorescence methods (free β-hCG was only tested using chemiluminescence). Laboratories using time-resolved fluorescence had overall higher sigma levels [total β-hCG: 9.56 (7.01-13.22) vs. 5.84 (4.36-9.12), W=53 114.00; PAPP-A: 9.04 (6.40-12.62) vs. 5.71 (4.22-8.15), W=75 752.00; both P<0.001] compared to those using chemiluminescence. The proportion of QC rules conforming to Westgard sigma rules ranged from 16.1% (31/193) to 19.6% (166/846). Among them, the proportion of laboratories with overly lenient QC rules was 24.8% (210/846) to 32.1% (62/193), and the proportion with overly strict QC rules was 51.8% (100/193) to 55.6% (470/846). Conclusion:The overall QC level of prenatal screening laboratories in China is fine, but there is still room for improvement in the setting of QC rules.

Objective To discuss how to plot a power function graph and draw power function graphs corresponding to common quality control rules to assist medical laboratories in selecting quality control rules.Methods Commonly used quality control rules in clinical laboratory testing in China were collected,power function graphs based on the Monte Carlo method were plotted,and the simulation results with existing results were compared and tested the reliability of the method.Results The Monte Carlo method could be used to easily plot power function graphs for the most complex quality control rules such as 13s/22s/R4s/41s/8(x-).This method had a high level of accuracy,but the accuracy and precision were positively correlated with the number of simulations.In terms of statistical proportions of seven commonly used quality control rules,the 13s/22srule had the highest usage proportion,followed by the 13s/22s/R4s.The power function graph corresponding to the 13s/22s/R4s/41s/10(x-) rule was plotted,and the sigma level lines were marked to assist the laboratory in selecting quality control rules.Conclusion The Monte Carlo method accurately plotted power function graphs,and medical laboratories could use this method to independently plot efficiency function graphs to meet quality control requirements.