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

In order to detect the environmental data of isolated cabin under various environmental conditions,a negative pressure cabin environment detector for aviation was developed,which was composed of a shell,a differential pressure transmitter,a pressure sensor,a carbon dioxide concentration sensor,an oxygen concentration sensor,a temperature and humidity sensor,a data processing module,a liquid crystal display(LCD)screen and USB data interface.It could environmental data such as carbon dioxide concentration,oxygen concentration,temperature,humidity,pressure difference between cabin and outside the cabin and air pressure outside the cabin in real time,the data processing module collected and processed the data,the data and data change curves was displayed in real time by the LCD screen,and the detection data was extracted through the USB data interface.When used in aviation environment,the detector could work continuously without fault for no less than 300 hours,and the average fault repair time was about 30 minutes,with good performance and high detection accuracy,which can provide convenience for the environmental data detection of negative pressure cabins,and is worthy of popularization.

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.

Objective:To summarize the clinical and genetic characteristics of children with Menkes disease(MD).Methods:The clinical manifestations, auxiliary examinations and genetic testing results of 15 MD children admitted to the Department of Pediatrics of the Third Affiliated Hospital of Zhengzhou University, Children′s Hospital Affiliated of Zhengzhou University and the First Affiliated Hospital of Zhengzhou University from June 2016 to October 2022 were analyzed retrospectively.These children were followed up.Results:All the 15 children were male.The age at onset was ranging from 9 days to 5.5 months.White skin, curly hair, skin laxity, hypotonia and severe developmental delay were found in all children, with epilepsy in 13 children, anemia in 11 children and granulocytopenia in 4 children.The concentration of ceruloplasmin in the serum of MD children was lower than that in healthy children of the same age.The concentration of ceruloplasmin in MD children younger than 3 months was significantly lower than that in healthy children of the same age and MD children older than 3 months.The brain magnetic resonance imaging showed abnormalities in all 15 children.Twelve children showed tortuous intracranial vessels in brain magnetic resonance angiography examinations.All the 15 children had ATP7A gene pathogenic variants, including 4 missense variants(2 cases with c. 2179G>A), 3 frameshift variants, 3 nonsense variants, 3 exon deletions and 2 splice site variants.Among these children, 1 had a novel gene variant that had not been reported so far(c.2968C>T). Conclusions:MD has early onset age and diverse clinical manifestations, but also has characteristic clinical manifestations and applicable auxiliary examinations.Its diagnosis depends on genetic testing.The c. 2179G>A and exon deletions may be hot mutations in Chinese MD patients.

OBJECTIVE: To explore the clinical characteristics and genetic basis for a child with X-linked lissencephaly with abnormal genitalia (XLAG). METHODS: A child with XLAG who had presented at the Third Affiliated Hospital of Zhengzhou University in May 2021 was selected as the study subject. Peripheral blood samples of the child and his parents were collected and subjected to high-throughput sequencing. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the result was analyzed by using bioinformatic software. RESULTS: The child was found to have harbored a hemizygous c.945_948del variant in exon 2 of the ARX gene, which as a frameshifting variant has resulted in a truncated protein. His mother was found to be heterozygous for the variant, whilst his father was of wild type. The variant was unreported previously. CONCLUSION The hemizygous c.945_948del variant of the ARX gene probably underlay the XLAG in this patient. Above finding has provided a basis for the diagnosis and genetic counseling for this family.
Humans ; Child ; Classical Lissencephalies and Subcortical Band Heterotopias ; Exons ; Computational Biology ; Genetic Counseling ; Genitalia ; Transcription Factors ; Homeodomain Proteins

Objective:To study the influence of periventricular-intraventricular hemorrhage (PVH-IVH) on cerebral blood flow (CBF) of preterm infants in the late postnatal period using arterial spin labeling (ASL) magnetic resonance imaging (MRI).Methods:From January 2023 to June 2023, 65 preterm infants (gestational age <32 weeks, birth weight <1 500 g) who were born in the Department of Obstetrics, Third Affiliated Hospital of Zhengzhou University and transferred to the Neonatal Intensive Care Unit were included in the prospective study.They were examined by the brain MRI and ASL at the corrected gestational age of 35-40 weeks.According to the results of the brain ultrasound within 1 week after birth, they were divided into the mild IVH group (25 cases) and the non-IVH group (40 cases). The CBF values in regions of interest (frontal lobe, temporal lobe, parietal lobe, occipital lobe, thalamus, and basal ganglia) on ASL images were compared.Multiple linear regression analysis was used to analyze the effect of PVH-IVH on CBF values in different ASL regions of interest, including frontal cortex, temporal cortex, parietal cortex, occipital cortex, thalamus, and basal ganglia.Results:Compared with those of non-IVH group, infants in the mild IVH group presented significantly older gestational age [29.0 (28.5, 30.4) weeks vs.28.2 (27.0, 31.0) weeks, Z=-2.398, P=0.016], higher hematocrit (HCT) in the latest examination prior to the brain MRI [29.6(26.4, 32.3)% vs.27.8 (25.6, 30.5)%, Z=-2.155, P=0.031], and larger body weight at the time of examination [2 015.0 (1 930.0, 2 127.5) g vs.1 950.0 (1 900.0, 1 997.5) g, Z=-3.314, P=0.001]. After adjustment for confounding factors of gestational age at birth, latest HCT and weight at the time of examination, the multivariable linear regression analysis showed that CBF values in the frontal lobe (95% CI: -8.367--4.042; P<0.001), temporal lobe (95% CI: -19.077--2.854; P=0.008), parietal lobe (95% CI: -8.344--3.502; P<0.001), occipital lobe (95% CI: -9.446--3.645; P<0.001), basal ganglia (95% CI: -7.543--1.963; P=0.001) and thalamus (95% CI: -8.051--2.372; P<0.001) were significantly lower in infants of the mild IVH group than those of non-IVH group. Conclusions:At the same corrected gestational age, mild IVH is correlated with low CBF values in local cerebral cortex and subcortical gray matter in premature infants.However, the predictive potential of CBF values in long-term neurological prognosis requires further explorations.

Humans ; Infant, Newborn ; Neonatal Screening ; China

Objective:To study the neurodevelopmental prognosis and risk factors for adverse outcomes of neonatal seizure.Methods:From December 2019 to November 2020, infants with neonatal seizure diagnosed in our hospital were enrolled in this retrospective study. Based on survival or not, mental development index (MDI), psychomotor development index (PDI) and seizure episodes at the age of 12 months, the infants were assigned into adverse outcome group and normal outcome group. The risk factors for adverse outcomes were statistically analyzed.Results:A total of 75 infants were enrolled,including 39 cases in adverse outcome group and 36 in normal outcome group. 69 cases showed abnormal amplitude-integrated electroencephalogram(aEEG), including 38 mildly abnormal cases,23 moderately abnormal cases and 8 severely abnormal cases, The incidences of adverse outcomes and mortality rates were significantly different ( P<0.05) among infants with different severity levels of aEEG abnormalities and the severity levels of aEEG abnormalities were positively correlated with adverse outcomes ( r=0.367, 0.471, P<0.05).Univariate analysis showed that adverse outcome group had significantly higher incidences of chorioamnionitis, seizure onset age ≤3 d, 5 min Apgar score ≤3, cranial ultrasound abnormalities, brain MR abnormalities and aEEG abnormalities than normal outcome group ( P<0.05).Logistic regression analysis showed that seizure onset age ≤3 d ( OR=3.988, 95% CI 1.376-11.674), abnormal brain MR ( OR=3.296, 95% CI 2.383-17.377) and bilirubin encephalopathy ( OR=3.792,95% CI 2.110-13.216) were independent risk factors for adverse outcomes of neonatal seizure. Conclusions:For neonatal seizure, the infants with more severe abnormal aEEG will have higher incidences of adverse outcomes and mortality. Seizure onset age ≤3 d, brain MR abnormalities and bilirubin encephalopathy were independent risk factors for adverse outcomes of neonatal seizure.