Objective:To provide basis for preventing flight safety accidents caused by hypoxia by exploring the subjective and objective performance of pilots in hypobaric hypoxia environment.Methods:The relevant data of pilots′ high altitude physiological training were retrospectively analyzed and a symptom questionnaire upon the training were summarized. The pilots were divided into excellent group (time of useful consciousness >6 min), good group (3 min ≤time of useful consciousness <6 min) and qualified group (2 min ≤time of useful consciousness <3 min) according to the time of useful consciousness. The hypoxia symptoms and physiological parameters of pilots in each group were statistically analyzed.Results:A total of 919 pilots were included, in which 416 were in excellent group, 490 were in good group and 13 were in qualified group. Among the 25 hypoxia symptoms, there were significant differences in the components of numbness and difficulty in calculation among 3 groups ( χ2=6.04, 7.79, P=0.049, 0.020), but there were no significant differences in the components of the other 23 hypoxia symptoms (all P>0.05). The changes of blood oxygen saturation were significant in group main effect, time main effect and their interaction ( F=25.65, 1 039.77, 25.22, all P<0.001). The change of heart rate was statistically significant in the main effect of time ( F=66.41, P<0.001) but in time main effect and their interaction (both P>0.05). There was no significant difference in respiratory rate among group main effect, time main effect and their interaction (all P>0.05). The distribution and variation of blood oxygen saturation were statistically significant differences among the 3 groups in the ranges of 81%-90%, 71%-80% and 65%-70% ( H=125.93, 372.83, 13.10, all P≤0.001) unlike the range of 91%-100% ( H=2.48, P=0.289). Conclusions:The excellent group showed better blood oxygen saturation maintaining and useful consciousness time enduring capabilities, and those imply them in better performance and consciousness that enable the operation in hypoxic environment with more ease.

Objective:To provide scientific basis for pilots′ hypoxia training by comparing and analyzing the effects of hypoxia training under normobaric and hypobaric environments.Methods:Forty-two healthy subjects were selected. The pilot reduced oxygen breathing device and hypobaric chamber were used to simulate 7 500 m hypoxia training, and blood oxygen saturation, heart rate, respiratory rate and hypoxia endurance time were monitored and recorded. The hypoxia symptom questionnaire was filled out by the subjects after 2 training sessions. The hypoxia endurance time and hypoxia tolerance grade of normobaric and hypobaric hypoxia training were analyzed, and the differences of blood oxygen saturation and hypoxia symptoms were compared between 2 hypoxia trainings.Results:Forty-two subjects completed the normobaric and hypobaric hypoxia trainings. The survival curve analysis of hypoxia endurance time showed that the median hypoxia endurance time of normobaric and hypobaric hypoxia training was [3.17(2.70, 3.64)] min and [3.67(3.46, 3.88)] min respectively, with no significant difference ( P>0.05). There was no significant difference in the grade distribution of hypoxia tolerance between 2 hypoxia trainings ( P>0.05). The blood oxygen saturation curves of 2 hypoxia trainings were basically consistent. There was no significant difference between 2 hypoxia trainings on blood oxygen saturation, heart rate and respiratory rate (all P>0.05). There were significant differences in difficulty in calculation, difficulty in concentration and with palpitation ( χ2=4.81, 3.97, 3.98, P=0.028, 0.046, 0.046). Conclusions:The analysis showed that most physiological responses and subjective symptoms of pilots are quite similar in the normobaric and hypobaric hypoxia training at simulated 7 500 m. Both normobaric and hypobaric exposures show the similar hypoxia training effect.

Objective:To investigate the repeatability of corneal topographic parameters with the Pentacam HR in patients with keratoconus of different severity.Methods:A diagnostic test study was performed.A total of 120 eyes from 98 patients with subclinical keratoconus or keratoconus were enrolled at Henan Eye Hospital from January 2019 to March 2022.The patients were divided into subclinical keratoconus group, mild keratoconus group, moderate keratoconus group and severe keratoconus group, with 30 eyes in each group.An additional 30 eyes of 30 subjects undergoing refractive surgery were selected as a control group.Three consecutive Pentacam HR measurements were performed by the same clinician.The recordings included a total of 53 parameters in anterior corneal surface, posterior corneal surface, thickness, composite index, and corneal densitometry.The within-subject standard deviation (Sw), repeatability limit ( r) and tolerance index (TI) were calculated to evaluate the repeatability of the parameters between different groups.This study adhered to the Declaration of Helsinki and was approved by the Ethics Committee of Henan Eye Hospital (No.HNEECKY-2019[5]).All subjects were informed of the purpose and significance of the study and signed an informed consent form before enrollment. Results:Compared with the control group, the TI of the subclinical, mild, moderate and severe keratoconus groups were 54.71%(29/53), 66.04%(35/53), 90.57%(48/53) and 94.34%(50/53), respectively, higher than 0.31.The steep keratometry (Ks), the maximum keratometry (Kmax) of the anterior corneal surface, the anterior corneal radius of curvature, the flat keratometry (Kf) of the posterior corneal surface, the posterior corneal radius of curvature (PRC), the thinnest corneal thickness (TCT), the average densitometry for the anterior 120 μm in the 0-2 mm area (A.0-2 mm), average densitometry for the anterior 120 μm in the 2-6 mm area (A.2-6 mm), average densitometry for the central tissue in the 0-2 mm area (C.2-6 mm), average densitometry for the total cornea in the 0-2 mm area (T.0-2 mm) and average densitometry for the total cornea in the 2-6 mm area (T.2-6 mm) showed good repeatability in the subclinical and mild keratoconus groups (TI<0.31).Kmax Zonal Mean 3 mm, posterior corneal surface mean keratometry, central keratoconus index showed good repeatability in subclinical, mild and moderate keratoconus groups.Kmax Zonal Mean 4 mm and Kmax Zonal Mean 5 mm showed good repeatability in all groups (TI<0.31).Conclusions:For patients with subclinical and mild keratoconus, Kf of the posterior corneal surface, PRC and TCT are recommended to monitor disease progression.To monitor the condition of patients with moderate and severe keratoconus, we may focus on the detection of Kmax Zonal Mean 4 mm and Kmax Zonal Mean 5 mm.

Objective To explore the clinical significance of serum cytokine expression in the hepatitis B surface antigen(HBsAg)sero-clearance in patients with severe hepatitis B.Methods A nested case-control trial was conducted on 14 inpatients with severe hepatitis B admitted in our hospital from 2006 to 2020.Of them,7 patients(aged 36.57±3.15 years)achieved HBsAg sero-clearance within 1 year after the onset of hepatitis B flares(with abrupt rise of ALT level to＞5 times the upper limit of normal during HBV infection)and were assigned into HBsAg clearance group,while the other 7 patients(aged 34.14±2.97 years)only obtained HBsAg decreased less than 1 g within 1 year after the onset(HBsAg non-clearance group).Then,multiplex liquid-chip assay based on Luminex xMAP was used to detect the expression levels of 48 cytokines such as IFN-γ and IL-2 in serum samples of these 14 patients.Results The serum levels IFN-γ,IL-2Ra and SDF-1α were significantly lower in the HBsAg clearance group than the HBsAg non-clearance group(P＜0.05),but no statistical differences were observed in other 39 cytokines between the 2 groups.And there were 5 cytokines having no mutual expression in both groups.The copy number of HBV DNA was positively correlated with serum HGF(r=0.675,P=0.008)and SDF-1α levels(r=0.587,P=0.027),while negatively with IP-10(r=-0.600,P=0.023)and MIG level(r=-0.640,P=0.014).Meanwhile,a positive correlation was found between HBsAg titer and IL12-p70 level(r=0.593,P=0.025),and a negative correlation between HBsAg titer and TNF-α level(r=-0.609,P=0.021).In addition,the serum total bilirubin level was positively correlated with the expression of SCGF-β(r=0.543,P=0.045).Conclusion Three differentially expressed cytokines and some cytokines related to HBV DNA level and HBsAg titer are found,which may provide new insights into the underlying immunological mechanism of HBV virus clearance caused by hepatitis flares.Meanwhile,it also provides potential biomarkers for HBsAg serological clearance in patients with severe hepatitis B.

Objective:To observe any effect of cooling on the amplitude of vibration-induced sensory nerve action potentials (SNAPs) in human digits.Methods:The middle fingers of 15 healthy adults were either cooled to about 22℃ using an ice pack or kept at about 32℃. A vibrator was applied to the joint connecting the middle finger and the palm vibrating with an amplitude of 2mm at a frequency of 60Hz. The amplitudes of middle finger SNAPs before, during and right after the vibration were recorded.Results:The SNAP amplitude at a given temperature was lower during vibration than before it, but it immediately returned to the pre-vibration level after the vibration ceased. The middle finger SNAP amplitudes at 22℃ were significantly higher than those at 32℃ throughout. The decrease in amplitude at 32℃ (61.7±15.1%) was significantly greater than that at 22℃ (24.1±7.0%).Conclusions:Cooling significantly reduces the effect of vibration on the amplitude of digital SNAPs. That suggests a way to protect the sensory nerves in hand-arm vibration syndrome.

Objective:To provide basis for preventing flight safety accidents caused by hypoxia by exploring the subjective and objective performance of pilots in hypobaric hypoxia environment.Methods:The relevant data of pilots′ high altitude physiological training were retrospectively analyzed and a symptom questionnaire upon the training were summarized. The pilots were divided into excellent group (time of useful consciousness >6 min), good group (3 min ≤time of useful consciousness <6 min) and qualified group (2 min ≤time of useful consciousness <3 min) according to the time of useful consciousness. The hypoxia symptoms and physiological parameters of pilots in each group were statistically analyzed.Results:A total of 919 pilots were included, in which 416 were in excellent group, 490 were in good group and 13 were in qualified group. Among the 25 hypoxia symptoms, there were significant differences in the components of numbness and difficulty in calculation among 3 groups ( χ2=6.04, 7.79, P=0.049, 0.020), but there were no significant differences in the components of the other 23 hypoxia symptoms (all P>0.05). The changes of blood oxygen saturation were significant in group main effect, time main effect and their interaction ( F=25.65, 1 039.77, 25.22, all P<0.001). The change of heart rate was statistically significant in the main effect of time ( F=66.41, P<0.001) but in time main effect and their interaction (both P>0.05). There was no significant difference in respiratory rate among group main effect, time main effect and their interaction (all P>0.05). The distribution and variation of blood oxygen saturation were statistically significant differences among the 3 groups in the ranges of 81%-90%, 71%-80% and 65%-70% ( H=125.93, 372.83, 13.10, all P≤0.001) unlike the range of 91%-100% ( H=2.48, P=0.289). Conclusions:The excellent group showed better blood oxygen saturation maintaining and useful consciousness time enduring capabilities, and those imply them in better performance and consciousness that enable the operation in hypoxic environment with more ease.

Objective:To provide scientific basis for pilots′ hypoxia training by comparing and analyzing the effects of hypoxia training under normobaric and hypobaric environments.Methods:Forty-two healthy subjects were selected. The pilot reduced oxygen breathing device and hypobaric chamber were used to simulate 7 500 m hypoxia training, and blood oxygen saturation, heart rate, respiratory rate and hypoxia endurance time were monitored and recorded. The hypoxia symptom questionnaire was filled out by the subjects after 2 training sessions. The hypoxia endurance time and hypoxia tolerance grade of normobaric and hypobaric hypoxia training were analyzed, and the differences of blood oxygen saturation and hypoxia symptoms were compared between 2 hypoxia trainings.Results:Forty-two subjects completed the normobaric and hypobaric hypoxia trainings. The survival curve analysis of hypoxia endurance time showed that the median hypoxia endurance time of normobaric and hypobaric hypoxia training was [3.17(2.70, 3.64)] min and [3.67(3.46, 3.88)] min respectively, with no significant difference ( P>0.05). There was no significant difference in the grade distribution of hypoxia tolerance between 2 hypoxia trainings ( P>0.05). The blood oxygen saturation curves of 2 hypoxia trainings were basically consistent. There was no significant difference between 2 hypoxia trainings on blood oxygen saturation, heart rate and respiratory rate (all P>0.05). There were significant differences in difficulty in calculation, difficulty in concentration and with palpitation ( χ2=4.81, 3.97, 3.98, P=0.028, 0.046, 0.046). Conclusions:The analysis showed that most physiological responses and subjective symptoms of pilots are quite similar in the normobaric and hypobaric hypoxia training at simulated 7 500 m. Both normobaric and hypobaric exposures show the similar hypoxia training effect.

Objective:To investigate the clinical characteristics of patients with keratoconus, and to explore the factors influencing keratoconus severity.Methods:A cross-sectional study was performed.A total of 908 patients (1 476 eyes) with primary keratoconus were enrolled in Henan Eye Hospital from January 2019 to December 2021.The medical history data of patients were collected by face-to-face questionnaire survey.Refractive parameters were measured by subjective optometry.Intraocular pressure (IOP) was measured by a non-contact tonometer, and corrected IOP was calculated by Dresden formula.Corneal topography parameters was obtained using Pentacam HR.The subgroup analysis of clinical characteristics of all patients was performed by age (<21 years, 21~<31 years, ≥31 years) and gender.Disease severity was graded based on steep keratometry (Ks), namely mild (Ks<48 D), moderate (48 D≤Ks<55 D) and severe (Ks≥55 D). The influencing factors of disease severity in keratoconus were analyzed by ordered Logistic regression.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of Henan Eye Hospital (No.HNEECKY-2019[5]). All subjects or guardians were informed of the purpose and significance of the study and written informed consent was obtained.Results:Of the 908 patients, 622 were with bilateral keratoconus and 286 were with unilateral keratoconus.The median age of onset was 20(17, 26) years, and the median age of diagnosis was 21(18, 27) years.The ratio of males to females was 3.05∶1.There were 9.80%(89/908) of the patients having a history of allergy, 25.55%(232/908) having a history of other systemic diseases, and 1.98%(18/908) having a family history of keratoconus.Of the 1 476 affected eyes, 27.57%(407/1 476) were diagnosed as severe keratoconus, and 61.94%(568/917) had a history of eye rubbing.The medians of sphericity, cylindricity, IOP, corrected IOP, Ks, thinnest corneal thickness (TCT), anterior corneal surface elevation (AE) and posterior corneal surface elevation (PE) were -4.00(-7.00, -1.75)D, -3.50(-6.00, -1.50)D, 12.00(10.30, 13.80)mmHg, 15.40(13.60, 17.00)mmHg, 49.85(46.40, 54.90)D, 460.00(425.00, 490.00)μm, 21.00(13.00, 34.75)μm, 51.00(33.00, 75.00)μm, respectively.The spherical refraction, IOP and corrected IOP were lower and the cylindrical refraction was higher in patients at age <21 years than in patients at age 21~<31 years, and the TCT of patients at age <21 years was higher than that at age ≥31 years, and the differences were statistically significant (all at P<0.05). Compared with female patients, male patients had younger onset age, lower spherical refraction, IOP and corrected IOP, as well as higher cylindrical refraction, AE and PE, showing statistically significant differences (all at P<0.05). The spherical refraction and IOP of male patients were lower than those of female patients at age <21 years, and the cylindrical refraction was higher in males than in females among the patients at age 21~<31 years, and the differences were statistically significant (both at P<0.05). Among the patients with onset age <21 years and diagnosis age <21 years, the ratio of males to females in patients with severe keratoconus was higher than those with mild and moderate disease, and the difference was statistically significant (both at P<0.05). Older age of onset was a protective factor for disease severity in keratoconus (odds ratio=0.981, 95% confidence interval: 0.963~0.999). Conclusions:The younger the onset age of keratoconus patients, the more severe the disease.Among the patients with severe keratoconus, there were more male patients, and males have a younger onset age and severer conditions.It is suggested that early screening of keratoconus in children and adolescents should be strengthened in clinical work, and more active prevention and treatment measures should be taken for younger patients, especially males.

By the end of 2021, a total of 915000 cases of occupational pneumoconiosis and 450000 existing cases have been reported nationwide. Silicosis is a common and serious pneumoconiosis disease caused by long-term inhalation of large amounts of free silica dust and extensive nodular fibrosis in the lungs. Because its specific pathogenic mechanism has not been elucidated and the relevant research progress is slow, there is still a lack of effective therapeutic and interventional drugs. With the increase of national attention and the unique advantages of Chinese materia medica in the treatment of silicosis, more and more studies have been conducted on the treatment of silicosis with active ingredients of Chinese materia medica in China, but most of them are still in preclinical research stage. This article mainly introduced the pharmacological action and mechanism of selected active components of Chinese materia medica in the intervention of silicosis from three aspects: anti-inflammation, anti-oxidation, and intervention of apoptosis, providing ideas for subsequent research and development of new drugs for silicosis. This article argues, it is considered that some traditional Chinese medicines must observe the pathological changes in the treatment of silicosis in the overall animal experiment, clarify their pharmacodynamic effects, and further study the multiple targets and pathways involved in them to elucidate their specific mechanisms of action. At the same time, it can strengthen the analysis of active ingredients of traditional Chinese medicine, or modify the structure of active ingredients, and then enhance its pharmacological activity in the treatment of silicosis, realizing the transformation of preclinical research stage to the results of clinical research.

Objective:To evaluate the protection performance of military transport aircraft oxygen system for aircrew and provide the physiological tests basis for product design finalization.Methods:Four dummies and 4 healthy volunteers who were equipped with individual protection equipment and military transport aircraft oxygen system completed 4 tests in altitude chamber including the oxygen supply performance physical test of oxygen system, the rapid decompression physical test of oxygen system, the physiological tests of oxygen continuously supplying for 6 h and oxygen supply performance test in rapid decompression at 12.0 km. Oxygen concentration, respiratory resistance, safety pressure, peak value, peak duration and steady pressure of mask under rapid decompression were tested. Electrocardiograph and oxygen saturation of volunteers were monitored.Results:The oxygen partial pressure provided by military transport aircraft oxygen system under 12.0 km was ≥19.1 kPa corresponding to the respiration ventilation volume of 20 L/min of dummy. The expiratory resistance was no higher than 441.3 Pa and the inspiration resistance was no higher than 490.3 Pa before the safety pressure connected. The peak pressure value in rapid decompression with 1.0 L lung volume of dummy was no higher than 5.8 kPa. The oxygen partial pressure provided by military transport aircraft oxygen system for volunteers was over 21.9 kPa in the 6 h cruising flight. All 4 volunteers successfully completed the rapid decompression physiological tests at 12.0 km with good subjective and objective responses.Conclusions:The protection performance of military transport aircraft oxygen system for aircrew can provide enough protection against the hypoxia up to 12.0 km