BACKGROUND Depression,anxiety,and insomnia were found out that were significant relevance to the mental health impact of the coronavirus disease 2019(COVID-19)lock-down.AIM To examine the interrelationships among perc...BACKGROUND Depression,anxiety,and insomnia were found out that were significant relevance to the mental health impact of the coronavirus disease 2019(COVID-19)lock-down.AIM To examine the interrelationships among perceived severity,anxiety,depression,insomnia,and sense of security in Chinese community residents during the COVID-19 lockdown period.METHODS Participants were selected using simple random sampling from four large gated communities in Chengdu,China.All participants were invited to complete a survey that included the Perceived Severity Questionnaire,Security Question-naire,Patient Health Questionnaire-9,Generalized Anxiety Disorder 7-item,and Insomnia Severity Index-7.In total,568 valid questionnaires were gathered.Co-rrelation analysis and structural equation models were used to explore the rela-RESULTS The observed prevalence rates of anxiety,depression,and insomnia among residents during lockdown were 27.5%,17.6%,and 16.0%,respectively.Correlation analysis showed that both perceived severity and sense of security were positively correlated with anxiety,depression,and insomnia[Pearson’s r was perceived severity and anxiety r=0.44(P<0.01);with depression r=0.48(P<0.01);with insomnia r=0.43(P<0.01);security with anxiety r=-0.65(P<0.01);with depression r=-0.65(P<0.01);with insomnia r=-0.53(P<0.01)].Structural equation modeling and bootstrap tests revealed that sense of security acted as a significant mediator in the relationship between perceived severity and emotional and sleep disorders(anxiety,depression,and insomnia).CONCLUSION This study demonstrates that sense of security is a significant predictor of emotional and sleep disorders(namely,depression,anxiety,and insomnia)among residents during the COVID-19 lockdown,with sense of security acting as a mediating factor.These findings suggest that mental health interventions for Chinese community residents during lockdowns may benefit from developing community-based educational programs to reduce perceived severity and ensuring the stable supply of essential resources and promoting social support networks to enhance the sense of security.展开更多
A new gas preparation system(GasPS-RCS)is proposed to solve two tasks:(A)to heat helium gas for tank pressurization;(B)to prepare gas for the Launch Vehicle(LV)Reactive Control System(RCS)at the LV orientation and sta...A new gas preparation system(GasPS-RCS)is proposed to solve two tasks:(A)to heat helium gas for tank pressurization;(B)to prepare gas for the Launch Vehicle(LV)Reactive Control System(RCS)at the LV orientation and stabilization sections of the LV on passive parts of the flight trajectory,to provide conditions for launching the Liquid Rocket Engine(LRE).The system includes a gas generator based on hydrogen peroxide,a separator for water separation,heat exchangers independent of the LRE,and gas-jet nozzles.The proposed new system allowed to reduce the length of pressurizing gas lines and reduce the increased helium gas consumption during the heat exchanger warm-up interval of the LRE during its launch.A special advantage of the proposed system is the possibility of ground testing of heat exchangers without an operating LRE.A mathematical model based on the first law of thermodynamics was used to perform a comparative analysis of GasPS-RCS with traditional pressurization and RCS systems.To validate the mathematical model,the experimental studies of helium pressurizing of a liquid nitrogen tank were conducted.The results show that the deviation of experimental and calculated values for pressure is 1.1%and for temperature up to 2%.According to the results of comparative analysis,the GasPS-RCS is 259 kg lighter for the first stage and 80 kg lighter for the second stage of the LV.展开更多
The problem of removing unused liquid propellant residues from the tanks of spent spacecraft and orbital stages of Launch Vehicles(LV)leads to their explosion and the formation of space debris in orbits.To provide a s...The problem of removing unused liquid propellant residues from the tanks of spent spacecraft and orbital stages of Launch Vehicles(LV)leads to their explosion and the formation of space debris in orbits.To provide a solution to this problem,a method for removing liquid propellant residues from the LV tanks after the mission completion is proposed.The method is based on the gasification of liquid propellant residues in the tanks under acoustic-vacuum exposure and the discharge of the gasification products into the surrounding outer space.Experimental investigations were carried out on a Ground-based Experimental Installation(GEI)to determine the coefficient of heat transfer from the surface of an acoustic radiator to a liquid.The obtained coefficient was then used to calculate the energy costs for the gasification of kerosene.Numerical estimates are given on the example of the tank with kerosene residues from a spent second stage of the LV“Soyuz-2.1 v”.The optimal discharge rate at which kerosene does not freeze is 0.14 m^(3)/s.Moreover,the acoustic exposure leads to an increase in the mass of evaporated kerosene over a given time by96.1%,and the energy costs are 1756.7 kJ(approximately 50% of the remaining electrical energy).展开更多
In this work,a novel type of short-process deformation technology of Mg alloys,bifurcation-equal channel angular pressing(B-ECAP),was proposed to refine grain and improve the basal texture.The cylindrical billets were...In this work,a novel type of short-process deformation technology of Mg alloys,bifurcation-equal channel angular pressing(B-ECAP),was proposed to refine grain and improve the basal texture.The cylindrical billets were first compressed into the die cavity,then sequentially flowed downward through a 90°corner and two 120°shear steps.The total strain of B-ECAP process could reach 3.924 in a single pass.The results of microstructure observation showed that DRX occurred at upsetting process in the die cavity and completed at position D.The grains were refined to 6.3μm at being extruded at 300℃ and grew obviously with the extrusion temperature increase.The shear tress induced by 900 corner and two 120°shear steps resulted in the basal poles of most grains tilted to extrusion direction(ED)by±25°.Compared with the original billets,the extruded sheets exhibited higher yield strengths(YS),which was mainly attributed to the grain refinement.The higher Schmid factor caused by ED-tilt texture resulted in a fracture elongation(FE)more than that of the original bar in ED,while was equivalent to that in transverse direction(TD).As the extrusion temperature increased,the variation of UTS and YS in ED and TD decreased gradually without ductility obviously decrease.展开更多
A microgravity environment has been shown to cause ocular damage and affect visual acuity,but the underlying mechanisms remain unclear.Therefore,we established an animal model of weightlessness via tail suspension to ...A microgravity environment has been shown to cause ocular damage and affect visual acuity,but the underlying mechanisms remain unclear.Therefore,we established an animal model of weightlessness via tail suspension to examine the pathological changes and molecular mechanisms of retinal damage under microgravity.After 4 weeks of tail suspension,there were no notable alterations in retinal function and morphology,while after 8 weeks of tail suspension,significant reductions in retinal function were observed,and the outer nuclear layer was thinner,with abundant apoptotic cells.To investigate the mechanism underlying the degenerative changes that occurred in the outer nuclear layer of the retina,proteomics was used to analyze differentially expressed proteins in rat retinas after 8 weeks of tail suspension.The results showed that the expression levels of fibroblast growth factor 2(also known as basic fibroblast growth factor)and glial fibrillary acidic protein,which are closely related to Müller cell activation,were significantly upregulated.In addition,Müller cell regeneration and Müller cell gliosis were observed after 4 and 8 weeks,respectively,of simulated weightlessness.These findings indicate that Müller cells play an important regulatory role in retinal outer nuclear layer degeneration during weightlessness.展开更多
The Normalized Diff erence Vegetation Index(NDVI),one of the earliest remote sensing analytical products used to simplify the complexities of multi-spectral imagery,is now the most popular index used for vegetation as...The Normalized Diff erence Vegetation Index(NDVI),one of the earliest remote sensing analytical products used to simplify the complexities of multi-spectral imagery,is now the most popular index used for vegetation assessment.This popularity and widespread use relate to how an NDVI can be calculated with any multispectral sensor with a visible and a near-IR band.Increasingly low costs and weights of multispectral sensors mean they can be mounted on satellite,aerial,and increasingly—Unmanned Aerial Systems(UAS).While studies have found that the NDVI is effective for expressing vegetation status andquantified vegetation attributes,its widespread use and popularity,especially in UAS applications,carry inherent risks of misuse with end users who received little to no remote sensing education.This article summarizes the progress of NDVI acquisition,highlights the areas of NDVI application,and addresses the critical problems and considerations in using NDVI.Detailed discussion mainly covers three aspects:atmospheric eff ect,saturation phenomenon,and sensor factors.The use of NDVI can be highly eff ective as long as its limitations and capabilities are understood.This consideration is particularly important to the UAS user community.展开更多
BACKGROUND Neurovascular compression(NVC) is the main cause of primary trigeminal neuralgia(TN) and hemifacial spasm(HFS). Microvascular decompression(MVD) is an effective surgical method for the treatment of TN and H...BACKGROUND Neurovascular compression(NVC) is the main cause of primary trigeminal neuralgia(TN) and hemifacial spasm(HFS). Microvascular decompression(MVD) is an effective surgical method for the treatment of TN and HFS caused by NVC. The judgement of NVC is a critical step in the preoperative evaluation of MVD, which is related to the effect of MVD treatment. Magnetic resonance imaging(MRI) technology has been used to detect NVC prior to MVD for several years. Among many MRI sequences, three-dimensional time-of-flight magnetic resonance angiography(3D TOF MRA) is the most widely used. However, 3D TOF MRA has some shortcomings in detecting NVC. Therefore, 3D TOF MRA combined with high resolution T2-weighted imaging(HR T2WI) is considered to be a more effective method to detect NVC.AIM To determine the value of 3D TOF MRA combined with HR T2WI in the judgment of NVC, and thus to assess its value in the preoperative evaluation of MVD.METHODS Related studies published from inception to September 2022 based on PubMed, Embase, Web of Science, and the Cochrane Library were retrieved. Studies that investigated 3D TOF MRA combined with HR T2WI to judge NVC in patients with TN or HFS were included according to the inclusion criteria. Studies without complete data or not relevant to the research topics were excluded. The Quality Assessment of Diagnostic Accuracy Studies checklist was used to assess the quality of included studies. The publication bias of the included literature was examined by Deeks’ test. An exact binomial rendition of the bivariate mixed-effects regression model was used to synthesize data. Data analysis was performed using the MIDAS module of statistical software Stata 16.0. Two independent investigators extracted patient and study characteristics, and discrepancies were resolved by consensus. Individual and pooled sensitivities and specificities were calculated. The I_(2) statistic and Q test were used to test heterogeneity. The study was registered on the website of PROSERO(registration No. CRD42022357158).RESULTS Our search identified 595 articles, of which 12(including 855 patients) fulfilled the inclusion criteria. Bivariate analysis showed that the pooled sensitivity and specificity of 3D TOF MRA combined with HR T2WI for detecting NVC were 0.96 [95% confidence interval(CI): 0.92-0.98] and 0.92(95%CI: 0.74-0.98), respectively. The pooled positive likelihood ratio was 12.4(95%CI: 3.2-47.8), pooled negative likelihood ratio was 0.04(95%CI: 0.02-0.09), and pooled diagnostic odds ratio was 283(95%CI: 50-1620). The area under the receiver operating characteristic curve was 0.98(95%CI: 0.97-0.99). The studies showed no substantial heterogeneity(I2 = 0, Q = 0.001 P = 0.50).CONCLUSION Our results suggest that 3D TOF MRA combined with HR T2WI has excellent sensitivity and specificity for judging NVC in patients with TN or HFS. This method can be used as an effective tool for preoperative evaluation of MVD.展开更多
AIM：To investigate the effects of hydrogen-rich saline（HRS）on microglia activation and Sirtuin type 1（Sirt1）in rats with N-methyl-N-nitrosourea（MNU）-induced retinitis pigmentosa（RP）.METHODS：Rats were divided...AIM：To investigate the effects of hydrogen-rich saline（HRS）on microglia activation and Sirtuin type 1（Sirt1）in rats with N-methyl-N-nitrosourea（MNU）-induced retinitis pigmentosa（RP）.METHODS：Rats were divided into norm（N）group,model（M）group and HRS（H）group.Rats in M and H groups were given saline and HRS respectively prior to and after administration of MNU.At one day（d1）and d3 afterwards,electroretinogram and histological examination were performed to confirm the effects of HRS on retinal function and structure of MNU-induced RP.Immunofluorescence staining of anti-ionized calcium-binding adapter molecule 1（Iba1）,a maker of microglia cells,was performed,with quantitative real-time polymerase chain reaction（qRT-PCR）for its m RNA quantification.Moreover,Sirt1 m RNA and protein expression in the retinas were detected by Western blot and qRT-PCR.RESULTS：HRS preserved the retinal function and mitigated the reduction of photoreceptor degeneration in MNU-treated retinas.The presence of microglia cells was somewhat more obvious in H group than that in M group at d1.HRS suppressed the further activation of microglia cells,with the number of microglia cells less than that of M group at d3.Results of qRT-PCR of Iba1 were consistent with those of immunofluorescence staining,with the m RNA expression of Iba1 in H group more intensive than that of M group at d1（P〈0.05）,while less than that of M group at d3（P〈0.05）.Furthermore,the Sirt1 m RNA and protein expression decreased after MNU administration,while HRS mitigated the MNU-induced downregulation of Sirt1.CONCLUSION：HRS can effectively keep microglia activation induced by MNU to an appropriate extent,while upregulate Sirt1 in MNU-induced RP.展开更多
Methane is the simplest hydrocarbon,consisting of one carbon atom and four hydrogen atoms.It is abundant in marsh gas,livestock rumination,and combustible ice.Little is known about the use of methane in human disease ...Methane is the simplest hydrocarbon,consisting of one carbon atom and four hydrogen atoms.It is abundant in marsh gas,livestock rumination,and combustible ice.Little is known about the use of methane in human disease treatment.Current research indicates that methane is useful for treating several diseases including ischemia and reperfusion injury,and inflammatory diseases.The mechanisms underlying the protective effects of methane appear primarily to involve anti-oxidation,anti-inflammation,and anti-apoptosis.In this review,we describe the beneficial effects of methane on different diseases,summarize possible mechanisms by which methane may act in these conditions,and discuss the purpose of methane production in hypoxic conditions.Then we propose several promising directions for the future research.展开更多
Previous studies have mostly focused on the effect of anthropogenic heating（AH） on air pollution events. However, few studies have investigated the impact of AH on the warm-sector precipitation over South China. By ...Previous studies have mostly focused on the effect of anthropogenic heating（AH） on air pollution events. However, few studies have investigated the impact of AH on the warm-sector precipitation over South China. By using the Weather Research and Forecasting model（WRF）coupled with an urban canopy model with appropriate AH release values, the warm-sector heavy rainfall event that occurred over the Pearl River Delta（PRD） during 8 May 2014 was investigated.The results show that the warm-sector precipitation of the PRD is sensitive to the impact of AH.By affecting the convection in the initiation of precipitation, AH can reduce the total precipitation of urban areas by approximately 10%. The possible mechanism by which AH influences the warm-sector heavy precipitation is described as follows： AH induced local convergence shifts towards the border of the PRD and intensified the convection and precipitation therein, by rearranging the thermal distributions of the flow field. In addition, AH changed the local convergence within the urban PRD areas, which was weakened by the homogenous urban thermal environment, and thereby decreased the total urban precipitation.展开更多
BACKGROUND The main pathophysiological basis of coronavirus disease 2019(COVID-19)causing respiratory failure is a cytokine storm and interleukin-6(IL-6)is an important component of the COVID-19 cytokine storm.As a sp...BACKGROUND The main pathophysiological basis of coronavirus disease 2019(COVID-19)causing respiratory failure is a cytokine storm and interleukin-6(IL-6)is an important component of the COVID-19 cytokine storm.As a specific antagonist of IL-6,tocilizumab may block the cytokine storm of COVID-19.The Diagnosis and Treatment Guidelines of New Coronavirus Pneumonia(7 th Edition)includes tocilizumab as a recommended drug for immunotherapy in severe and critical COVID-19 patients.However,the specific clinical efficacy of tocilizumab in the treatment of COVID-19 patients is worth studying.AIM To determine the clinical efficacy of tocilizumab in inhibiting the cytokine storm in COVID-19.METHODS In total,19 severe and critical COVID-19 patients were enrolled in this study,and were treated with tocilizumab in Optical Valley Campus of Hubei Maternal and Child Health Care Hospital from February 20 to March 31,2020.The imaging manifestations and clinical data before and after treatment were analyzed retrospectively,including routine peripheral venous blood tests,routine blood biochemical tests,coagulation test,C-reactive protein(CRP),IL-6,and arterial blood gas analysis.RESULTS Of the 19 patients in this group,13(68.4%)had significantly improved symptoms of COVID-19(5 patients were discharged directly and 8 patients were transferred after improvement)following treatment.One case was invalid,1 case was exacerbated,and 4 deaths(21.1%)were observed(all critical cases).The lymphocyte count,CRP,lactic acid,oxygenation index,fibrinogen(FIB)and IL-6 levels were significantly different in the improved group.CONCLUSION Tocilizumab treatment is effective against IL-6 in COVID-19 patients,but it does not completely inhibit the inflammation and cytokine storm in all patients with COVID-19.In the clinical treatment of COVID-19 patients,attention should be paid to the timing of drug administration and other adjuvant treatments.展开更多
For the two-step foaming method, one of the most cost-effective ways to fabricate three-dimensional shaped aluminum alloy foams with dense outer surface skin, it is crucial to describe and predict the mold- filling be...For the two-step foaming method, one of the most cost-effective ways to fabricate three-dimensional shaped aluminum alloy foams with dense outer surface skin, it is crucial to describe and predict the mold- filling behavior of the shaped aluminum alloy foams with a favorable pore-distribution accurately. In this paper, a mold-filling model for semi-solid aluminum alloy foams was initially established and subse- quently employed to predict the filling height, which represents the mold-filling ability of semi-solid aluminum alloy foams in a specially designed tube-like mold. Our results indicate that the proposed model can be applied to characterize the mold-filling property of aluminum alloy melts in a quantitative manner. Theoretically, our findings actually provide a guideline for mass-production of the shaped aluminum alloy foams by using the two-step foaming process,展开更多
AIM:To investigate therapeutic effects of traditional Chinese medicine formulations,Hexuemingmu(HXMM)on laser-induced choroidal neovascularization(CNV)and followup effect in mice.METHODS:C57 BL/6 mice of 8-week-old we...AIM:To investigate therapeutic effects of traditional Chinese medicine formulations,Hexuemingmu(HXMM)on laser-induced choroidal neovascularization(CNV)and followup effect in mice.METHODS:C57 BL/6 mice of 8-week-old were used and CNV was induced with 577 nm laser photocoagulation.Animals were randomly divided into groups and different doses of HXMM were administered daily.One,four,and eight weeks after the intervention,the electroretinogram(ERG),fundus fluorescence angiography,choroidal flat mount and immunofluorescence staining were preformed to evaluate the function and CNV formation.The expression levels of angiogenic proteins were determined by Western blotting and immunofluorescence staining.An analysis of variance and Kruskal-Wallis test were used to test the differences among the groups.RESULTS:The results showed that HXMM effectively increased amplitude of ERG of mice(P<0.05),alleviated fundus CNV leakage(P<0.05),and reduced the area of neovascularization and the expression of angiogenic proteins(P<0.05)after laser-induced CNV.CONCLUSION:HXMM can protect the retinal function of mice after laser-induced CNV,and inhibit the CNV development.展开更多
In six healthy male subjects, the changes of respiratory airflow rate and heart rate were de-termined in sensory units of five just noticeable difference （JND） steps caused by inspiratory resistive （IR） loads rang...In six healthy male subjects, the changes of respiratory airflow rate and heart rate were de-termined in sensory units of five just noticeable difference （JND） steps caused by inspiratory resistive （IR） loads ranging 0.28-1. 62 kPa.L<sup>-1</sup> s and physical stimuli in IR corresponding to JND steps andcombined resistance （CR） of different ratios equivalent to 2, 4 JND sensation at rest and duringmild and moderate muscular exercises (250 and 500 kgm·min<sup>-1</sup>) performed on a bicycle ergometer.The results suggest that the tendency of effects on respiratory pattern, within the test range of IRloads, are approximately consistent at rest and during mild and moderate exercise, that when theCR load is carried, the changes of respiratory pattern at rest and during mild exercise are similar,but more apparently during moderate exercise, and that the heart rote only increases with the rise ofexertion intensity, without apparent influence of resistive loads.展开更多
The oil-soluble cadmium dipropyldithiophosphate additive was synthesized. A four-ball tester was used to evaluate the tribological performance of the additive in a mineral oil under different loads and lubricant greas...The oil-soluble cadmium dipropyldithiophosphate additive was synthesized. A four-ball tester was used to evaluate the tribological performance of the additive in a mineral oil under different loads and lubricant grease synthesized compared with some commercial additives. The results show that it exhibits excellent antiwear and load-carrying capacities and is better than other additives. The surface analytical tools such as scanning electron microscope (SEM) with energy dispersive X-ray (EDX), X-ray photoelectron spectrometer (XPS) were used to investigate the topography, the compositions, and chemical states of some typical elements on the rubbing surface of worn scar.Smooth and light topography of worn scar further confirms that the additive shows good antiwear capacities. The results of EDX and XPS analyses indicate that tribochemical mixed protective films consisting of atomic cadmium, sulphides, sulphates and phosphates are formed on the rubbing surface, which contribute to improving the tribological properties of lubricant and grease. Particularly, the soft cadmium film formed plays an important role in improving antiwear properties of oils. Finally, antiwear mechanism of the additive and formation scheme of atomic cadmium was proposed.展开更多
Retinal injury after blunt ocular trauma may directly affect prognosis and lead to vision loss.To investigate the pathological changes and molecular mechanisms involved in retinal injury after blunt ocular trauma,we e...Retinal injury after blunt ocular trauma may directly affect prognosis and lead to vision loss.To investigate the pathological changes and molecular mechanisms involved in retinal injury after blunt ocular trauma,we established a weight drop injury model of blunt ocular trauma in male Beagle dogs.Hematoxylin-eosin staining,immunofluorescence staining,western blotting,and TUNEL assays were performed to investigate retinal injury within 14 days after blunt ocular trauma.Compared with the control group,the thicknesses of the inner and outer nuclear layers,as well as the number of retinal ganglion cells,gradually decreased within 14 days after injury.The number of bipolar cells in the inner nuclear layer began to decrease 1 day after injury,while the numbers of cholinergic and amacrine cells in the inner nuclear layer did not decrease until 7 days after injury.Moreover,retinal cell necroptosis increased with time after injury;it progressed from the ganglion cell layer to the outer nuclear layer.Visual electrophysiological findings indicated that visual impairment began on the first day after injury and worsened over time.Additionally,blunt ocular trauma induced nerve regeneration and Müller glial hyperplasia;it also resulted in the recruitment of microglia to the retina and polarization of those microglia to the M1 phenotype.These findings suggest that necroptosis plays an important role in exacerbating retinal injury after blunt ocular trauma via gliosis and neuroinflammation.Such a role has important implications for the development of therapeutic strategies.展开更多
Organic-based materials are often used as the coating of metal oilcans. But they need to be sprayed several times in the whole life of oilcans because of the short-life of organic components. To overcome this problem,...Organic-based materials are often used as the coating of metal oilcans. But they need to be sprayed several times in the whole life of oilcans because of the short-life of organic components. To overcome this problem, a type of long-life flexible cement-based anti-corrosion material used on the surface of metal oilcans was developed according to the principle that the steel reinforced concrete can remain the same life with buildings. The materials with different formulas composed of acrylic ~nulsion, cement and other additives were prepared. Because the ratios of polymer to cement played the decisive role in the adhesion and anti-corrosion characteristics, their effects on the physical performances were investigated by comparing the mechanical properties, anti-corrosion and anti-aging properties. The relationship between microstructure and macroscopic properties was also discussed.展开更多
The surface performances of directly fluorinated high density polyethylene （HDPE） are studied with Fourier transform infrared （FT-IR） spectra, scanning electron microscopy （SEM） and contact angle （CA） system. ...The surface performances of directly fluorinated high density polyethylene （HDPE） are studied with Fourier transform infrared （FT-IR） spectra, scanning electron microscopy （SEM） and contact angle （CA） system. The SEM images show that there is a three-layer structure called the reaction, virgin and boundary layer structure. The depth of fluorinated layer is 5.75 ~m with 1 h fluorination time and 7.86 b^m with 2 h. The depths are 5.46 /~m and 5.07 /~m when fluorine density is 2G and 1~/0, respectively. CA indicates that the HDPE surface property becomes more hydrophobic with the increasing water contact angle from 78.5~ to 104.5~. Oleophobic and hydrophobic features of HDPE are identified by comparison of mass change experiments. It is shown that the in- crement rate of fluorinated HDPE is much lower than that of un-fluorinated HDPE filled in neither distilled water nor jet fuel.展开更多
BACKGROUND Specific pulmonary infection could seriously threaten the health of pilots and their companions.The consequences are serious.We investigated the clinical diagnosis,treatment,and medical identification of sp...BACKGROUND Specific pulmonary infection could seriously threaten the health of pilots and their companions.The consequences are serious.We investigated the clinical diagnosis,treatment,and medical identification of specific pulmonary infections in naval pilots.CASE SUMMARY We analyzed the medical waiver and clinical data of four pilots with specific pulmonary infections,who had accepted treatment at the Naval Medical Center of Chinese People’s Liberation Army between January 2020 and November 2021,including three cases of tuberculosis and one of cryptococcal pneumonia.All cases underwent a series of comprehensive treatment courses.Three cases successfully obtained medical waiver for flight after being cured,while one was grounded after reaching the maximum flight life after being cured.CONCLUSION Chest computed tomography scanning should be used instead of chest radiography in pilots’physical examination.Most pilots with specific pulmonary infection can be cured and return to flight.展开更多
基金Supported by Young Talent Project of Air Force Medical Center,No.2022YXQN008and Rapid Response Project of Air Force Medical University,No.2023KXKT041.
文摘BACKGROUND Depression,anxiety,and insomnia were found out that were significant relevance to the mental health impact of the coronavirus disease 2019(COVID-19)lock-down.AIM To examine the interrelationships among perceived severity,anxiety,depression,insomnia,and sense of security in Chinese community residents during the COVID-19 lockdown period.METHODS Participants were selected using simple random sampling from four large gated communities in Chengdu,China.All participants were invited to complete a survey that included the Perceived Severity Questionnaire,Security Question-naire,Patient Health Questionnaire-9,Generalized Anxiety Disorder 7-item,and Insomnia Severity Index-7.In total,568 valid questionnaires were gathered.Co-rrelation analysis and structural equation models were used to explore the rela-RESULTS The observed prevalence rates of anxiety,depression,and insomnia among residents during lockdown were 27.5%,17.6%,and 16.0%,respectively.Correlation analysis showed that both perceived severity and sense of security were positively correlated with anxiety,depression,and insomnia[Pearson’s r was perceived severity and anxiety r=0.44(P<0.01);with depression r=0.48(P<0.01);with insomnia r=0.43(P<0.01);security with anxiety r=-0.65(P<0.01);with depression r=-0.65(P<0.01);with insomnia r=-0.53(P<0.01)].Structural equation modeling and bootstrap tests revealed that sense of security acted as a significant mediator in the relationship between perceived severity and emotional and sleep disorders(anxiety,depression,and insomnia).CONCLUSION This study demonstrates that sense of security is a significant predictor of emotional and sleep disorders(namely,depression,anxiety,and insomnia)among residents during the COVID-19 lockdown,with sense of security acting as a mediating factor.These findings suggest that mental health interventions for Chinese community residents during lockdowns may benefit from developing community-based educational programs to reduce perceived severity and ensuring the stable supply of essential resources and promoting social support networks to enhance the sense of security.
基金supported by the Ministry of Education and Science of the Russian Federation(No.2019-0251).
文摘A new gas preparation system(GasPS-RCS)is proposed to solve two tasks:(A)to heat helium gas for tank pressurization;(B)to prepare gas for the Launch Vehicle(LV)Reactive Control System(RCS)at the LV orientation and stabilization sections of the LV on passive parts of the flight trajectory,to provide conditions for launching the Liquid Rocket Engine(LRE).The system includes a gas generator based on hydrogen peroxide,a separator for water separation,heat exchangers independent of the LRE,and gas-jet nozzles.The proposed new system allowed to reduce the length of pressurizing gas lines and reduce the increased helium gas consumption during the heat exchanger warm-up interval of the LRE during its launch.A special advantage of the proposed system is the possibility of ground testing of heat exchangers without an operating LRE.A mathematical model based on the first law of thermodynamics was used to perform a comparative analysis of GasPS-RCS with traditional pressurization and RCS systems.To validate the mathematical model,the experimental studies of helium pressurizing of a liquid nitrogen tank were conducted.The results show that the deviation of experimental and calculated values for pressure is 1.1%and for temperature up to 2%.According to the results of comparative analysis,the GasPS-RCS is 259 kg lighter for the first stage and 80 kg lighter for the second stage of the LV.
基金co-supported by the:state assignment of the Ministry of Education and Science of the Russian Federation-“Research of liquid vaporization processes in the fuel tanks of launch vehicles to improve the environmental safety and economic efficiency of launch vehicles with liquidpropellant rocket engines”(No.2019-0251)state assignment of the Institute of Mathematics of the Siberian Branch of the Russian Academy of Sciences-“Models and methods of data processing to support decision-making processes”(No.FWNF-2022-0016)。
文摘The problem of removing unused liquid propellant residues from the tanks of spent spacecraft and orbital stages of Launch Vehicles(LV)leads to their explosion and the formation of space debris in orbits.To provide a solution to this problem,a method for removing liquid propellant residues from the LV tanks after the mission completion is proposed.The method is based on the gasification of liquid propellant residues in the tanks under acoustic-vacuum exposure and the discharge of the gasification products into the surrounding outer space.Experimental investigations were carried out on a Ground-based Experimental Installation(GEI)to determine the coefficient of heat transfer from the surface of an acoustic radiator to a liquid.The obtained coefficient was then used to calculate the energy costs for the gasification of kerosene.Numerical estimates are given on the example of the tank with kerosene residues from a spent second stage of the LV“Soyuz-2.1 v”.The optimal discharge rate at which kerosene does not freeze is 0.14 m^(3)/s.Moreover,the acoustic exposure leads to an increase in the mass of evaporated kerosene over a given time by96.1%,and the energy costs are 1756.7 kJ(approximately 50% of the remaining electrical energy).
基金Projects(52274397,52275382)supported by the National Natural Science Foundation of ChinaProject(tsqn202211115)supported by the Taishan Scholars Program of Shandong Province,China+2 种基金Project supported by the Yantai High-end Talent Introduction“Double Hundred Plan”(2021),ChinaProject(ZR2024JQ020)supported by the Shandong Provincial Natural Science Foundation of ChinaProjects(CZ20210034,CM20223013)supported by the Changzhou Sci&Tech Program,China。
文摘In this work,a novel type of short-process deformation technology of Mg alloys,bifurcation-equal channel angular pressing(B-ECAP),was proposed to refine grain and improve the basal texture.The cylindrical billets were first compressed into the die cavity,then sequentially flowed downward through a 90°corner and two 120°shear steps.The total strain of B-ECAP process could reach 3.924 in a single pass.The results of microstructure observation showed that DRX occurred at upsetting process in the die cavity and completed at position D.The grains were refined to 6.3μm at being extruded at 300℃ and grew obviously with the extrusion temperature increase.The shear tress induced by 900 corner and two 120°shear steps resulted in the basal poles of most grains tilted to extrusion direction(ED)by±25°.Compared with the original billets,the extruded sheets exhibited higher yield strengths(YS),which was mainly attributed to the grain refinement.The higher Schmid factor caused by ED-tilt texture resulted in a fracture elongation(FE)more than that of the original bar in ED,while was equivalent to that in transverse direction(TD).As the extrusion temperature increased,the variation of UTS and YS in ED and TD decreased gradually without ductility obviously decrease.
基金supported by the Army Laboratory Animal Foundation of China,No.SYDW[2020]22(to TC)the Shaanxi Provincial Key R&D Plan General Project of China,No.2022SF-236(to YM)the National Natural Science Foundation of China,No.82202070(to TC)。
文摘A microgravity environment has been shown to cause ocular damage and affect visual acuity,but the underlying mechanisms remain unclear.Therefore,we established an animal model of weightlessness via tail suspension to examine the pathological changes and molecular mechanisms of retinal damage under microgravity.After 4 weeks of tail suspension,there were no notable alterations in retinal function and morphology,while after 8 weeks of tail suspension,significant reductions in retinal function were observed,and the outer nuclear layer was thinner,with abundant apoptotic cells.To investigate the mechanism underlying the degenerative changes that occurred in the outer nuclear layer of the retina,proteomics was used to analyze differentially expressed proteins in rat retinas after 8 weeks of tail suspension.The results showed that the expression levels of fibroblast growth factor 2(also known as basic fibroblast growth factor)and glial fibrillary acidic protein,which are closely related to Müller cell activation,were significantly upregulated.In addition,Müller cell regeneration and Müller cell gliosis were observed after 4 and 8 weeks,respectively,of simulated weightlessness.These findings indicate that Müller cells play an important regulatory role in retinal outer nuclear layer degeneration during weightlessness.
基金the USDA National Institute of Food and Agriculture McIntire Stennis project(IND011523MS).
文摘The Normalized Diff erence Vegetation Index(NDVI),one of the earliest remote sensing analytical products used to simplify the complexities of multi-spectral imagery,is now the most popular index used for vegetation assessment.This popularity and widespread use relate to how an NDVI can be calculated with any multispectral sensor with a visible and a near-IR band.Increasingly low costs and weights of multispectral sensors mean they can be mounted on satellite,aerial,and increasingly—Unmanned Aerial Systems(UAS).While studies have found that the NDVI is effective for expressing vegetation status andquantified vegetation attributes,its widespread use and popularity,especially in UAS applications,carry inherent risks of misuse with end users who received little to no remote sensing education.This article summarizes the progress of NDVI acquisition,highlights the areas of NDVI application,and addresses the critical problems and considerations in using NDVI.Detailed discussion mainly covers three aspects:atmospheric eff ect,saturation phenomenon,and sensor factors.The use of NDVI can be highly eff ective as long as its limitations and capabilities are understood.This consideration is particularly important to the UAS user community.
基金Supported by the Key Research and Development Plan of Shaanxi Province,No.2021SF-298.
文摘BACKGROUND Neurovascular compression(NVC) is the main cause of primary trigeminal neuralgia(TN) and hemifacial spasm(HFS). Microvascular decompression(MVD) is an effective surgical method for the treatment of TN and HFS caused by NVC. The judgement of NVC is a critical step in the preoperative evaluation of MVD, which is related to the effect of MVD treatment. Magnetic resonance imaging(MRI) technology has been used to detect NVC prior to MVD for several years. Among many MRI sequences, three-dimensional time-of-flight magnetic resonance angiography(3D TOF MRA) is the most widely used. However, 3D TOF MRA has some shortcomings in detecting NVC. Therefore, 3D TOF MRA combined with high resolution T2-weighted imaging(HR T2WI) is considered to be a more effective method to detect NVC.AIM To determine the value of 3D TOF MRA combined with HR T2WI in the judgment of NVC, and thus to assess its value in the preoperative evaluation of MVD.METHODS Related studies published from inception to September 2022 based on PubMed, Embase, Web of Science, and the Cochrane Library were retrieved. Studies that investigated 3D TOF MRA combined with HR T2WI to judge NVC in patients with TN or HFS were included according to the inclusion criteria. Studies without complete data or not relevant to the research topics were excluded. The Quality Assessment of Diagnostic Accuracy Studies checklist was used to assess the quality of included studies. The publication bias of the included literature was examined by Deeks’ test. An exact binomial rendition of the bivariate mixed-effects regression model was used to synthesize data. Data analysis was performed using the MIDAS module of statistical software Stata 16.0. Two independent investigators extracted patient and study characteristics, and discrepancies were resolved by consensus. Individual and pooled sensitivities and specificities were calculated. The I_(2) statistic and Q test were used to test heterogeneity. The study was registered on the website of PROSERO(registration No. CRD42022357158).RESULTS Our search identified 595 articles, of which 12(including 855 patients) fulfilled the inclusion criteria. Bivariate analysis showed that the pooled sensitivity and specificity of 3D TOF MRA combined with HR T2WI for detecting NVC were 0.96 [95% confidence interval(CI): 0.92-0.98] and 0.92(95%CI: 0.74-0.98), respectively. The pooled positive likelihood ratio was 12.4(95%CI: 3.2-47.8), pooled negative likelihood ratio was 0.04(95%CI: 0.02-0.09), and pooled diagnostic odds ratio was 283(95%CI: 50-1620). The area under the receiver operating characteristic curve was 0.98(95%CI: 0.97-0.99). The studies showed no substantial heterogeneity(I2 = 0, Q = 0.001 P = 0.50).CONCLUSION Our results suggest that 3D TOF MRA combined with HR T2WI has excellent sensitivity and specificity for judging NVC in patients with TN or HFS. This method can be used as an effective tool for preoperative evaluation of MVD.
基金Supported by the Natural Science Foundation of China(No.81300836)the Foundation of Open Sharing Platform of Science and Technology of Shaanxi Province,China(No.2015FWPT-02)
文摘AIM：To investigate the effects of hydrogen-rich saline（HRS）on microglia activation and Sirtuin type 1（Sirt1）in rats with N-methyl-N-nitrosourea（MNU）-induced retinitis pigmentosa（RP）.METHODS：Rats were divided into norm（N）group,model（M）group and HRS（H）group.Rats in M and H groups were given saline and HRS respectively prior to and after administration of MNU.At one day（d1）and d3 afterwards,electroretinogram and histological examination were performed to confirm the effects of HRS on retinal function and structure of MNU-induced RP.Immunofluorescence staining of anti-ionized calcium-binding adapter molecule 1（Iba1）,a maker of microglia cells,was performed,with quantitative real-time polymerase chain reaction（qRT-PCR）for its m RNA quantification.Moreover,Sirt1 m RNA and protein expression in the retinas were detected by Western blot and qRT-PCR.RESULTS：HRS preserved the retinal function and mitigated the reduction of photoreceptor degeneration in MNU-treated retinas.The presence of microglia cells was somewhat more obvious in H group than that in M group at d1.HRS suppressed the further activation of microglia cells,with the number of microglia cells less than that of M group at d3.Results of qRT-PCR of Iba1 were consistent with those of immunofluorescence staining,with the m RNA expression of Iba1 in H group more intensive than that of M group at d1（P〈0.05）,while less than that of M group at d3（P〈0.05）.Furthermore,the Sirt1 m RNA and protein expression decreased after MNU administration,while HRS mitigated the MNU-induced downregulation of Sirt1.CONCLUSION：HRS can effectively keep microglia activation induced by MNU to an appropriate extent,while upregulate Sirt1 in MNU-induced RP.
文摘Methane is the simplest hydrocarbon,consisting of one carbon atom and four hydrogen atoms.It is abundant in marsh gas,livestock rumination,and combustible ice.Little is known about the use of methane in human disease treatment.Current research indicates that methane is useful for treating several diseases including ischemia and reperfusion injury,and inflammatory diseases.The mechanisms underlying the protective effects of methane appear primarily to involve anti-oxidation,anti-inflammation,and anti-apoptosis.In this review,we describe the beneficial effects of methane on different diseases,summarize possible mechanisms by which methane may act in these conditions,and discuss the purpose of methane production in hypoxic conditions.Then we propose several promising directions for the future research.
基金supported by the Special Scientific Research Fund of the Meteorological Public Welfare of the Ministry of Sciences and Technology,China(Grant No.GYHY201406003)the National Natural Science Foundation of China(Grant Nos.41375054,41575064,and 41375052)+1 种基金the Applied Basic Research Programs of the Science and Technology Department of Sichuan Province(Grant No.2015JY0109)the Starting Foundation of Civil Aviation University of China(Grant No.2016QD05X)
文摘Previous studies have mostly focused on the effect of anthropogenic heating（AH） on air pollution events. However, few studies have investigated the impact of AH on the warm-sector precipitation over South China. By using the Weather Research and Forecasting model（WRF）coupled with an urban canopy model with appropriate AH release values, the warm-sector heavy rainfall event that occurred over the Pearl River Delta（PRD） during 8 May 2014 was investigated.The results show that the warm-sector precipitation of the PRD is sensitive to the impact of AH.By affecting the convection in the initiation of precipitation, AH can reduce the total precipitation of urban areas by approximately 10%. The possible mechanism by which AH influences the warm-sector heavy precipitation is described as follows： AH induced local convergence shifts towards the border of the PRD and intensified the convection and precipitation therein, by rearranging the thermal distributions of the flow field. In addition, AH changed the local convergence within the urban PRD areas, which was weakened by the homogenous urban thermal environment, and thereby decreased the total urban precipitation.
文摘BACKGROUND The main pathophysiological basis of coronavirus disease 2019(COVID-19)causing respiratory failure is a cytokine storm and interleukin-6(IL-6)is an important component of the COVID-19 cytokine storm.As a specific antagonist of IL-6,tocilizumab may block the cytokine storm of COVID-19.The Diagnosis and Treatment Guidelines of New Coronavirus Pneumonia(7 th Edition)includes tocilizumab as a recommended drug for immunotherapy in severe and critical COVID-19 patients.However,the specific clinical efficacy of tocilizumab in the treatment of COVID-19 patients is worth studying.AIM To determine the clinical efficacy of tocilizumab in inhibiting the cytokine storm in COVID-19.METHODS In total,19 severe and critical COVID-19 patients were enrolled in this study,and were treated with tocilizumab in Optical Valley Campus of Hubei Maternal and Child Health Care Hospital from February 20 to March 31,2020.The imaging manifestations and clinical data before and after treatment were analyzed retrospectively,including routine peripheral venous blood tests,routine blood biochemical tests,coagulation test,C-reactive protein(CRP),IL-6,and arterial blood gas analysis.RESULTS Of the 19 patients in this group,13(68.4%)had significantly improved symptoms of COVID-19(5 patients were discharged directly and 8 patients were transferred after improvement)following treatment.One case was invalid,1 case was exacerbated,and 4 deaths(21.1%)were observed(all critical cases).The lymphocyte count,CRP,lactic acid,oxygenation index,fibrinogen(FIB)and IL-6 levels were significantly different in the improved group.CONCLUSION Tocilizumab treatment is effective against IL-6 in COVID-19 patients,but it does not completely inhibit the inflammation and cytokine storm in all patients with COVID-19.In the clinical treatment of COVID-19 patients,attention should be paid to the timing of drug administration and other adjuvant treatments.
基金supported by 111 Project(Grant No.B07003)the Program for Changjiang Scholars and Innovative Research Team in University(Grant No.IRT_14R05)+3 种基金the Fundamental Research Funds for the Central Universities(Grant No.FRF-SD-12-004A)the Special Scientific Research Fund for Doctoral Program of the Ministry of Education of the People’s Republic of China(Grant No.20110006110029)Beijing Higher Education Young Elite Teacher Projectthe Research Project of the State Key Laboratory for Advanced Metals and Materials,University of Science and Technology Beijing(Grant No.2011-Z13)
文摘For the two-step foaming method, one of the most cost-effective ways to fabricate three-dimensional shaped aluminum alloy foams with dense outer surface skin, it is crucial to describe and predict the mold- filling behavior of the shaped aluminum alloy foams with a favorable pore-distribution accurately. In this paper, a mold-filling model for semi-solid aluminum alloy foams was initially established and subse- quently employed to predict the filling height, which represents the mold-filling ability of semi-solid aluminum alloy foams in a specially designed tube-like mold. Our results indicate that the proposed model can be applied to characterize the mold-filling property of aluminum alloy melts in a quantitative manner. Theoretically, our findings actually provide a guideline for mass-production of the shaped aluminum alloy foams by using the two-step foaming process,
基金the Army Laboratory Animal Foundation of China(No.SYDW2016-011)。
文摘AIM:To investigate therapeutic effects of traditional Chinese medicine formulations,Hexuemingmu(HXMM)on laser-induced choroidal neovascularization(CNV)and followup effect in mice.METHODS:C57 BL/6 mice of 8-week-old were used and CNV was induced with 577 nm laser photocoagulation.Animals were randomly divided into groups and different doses of HXMM were administered daily.One,four,and eight weeks after the intervention,the electroretinogram(ERG),fundus fluorescence angiography,choroidal flat mount and immunofluorescence staining were preformed to evaluate the function and CNV formation.The expression levels of angiogenic proteins were determined by Western blotting and immunofluorescence staining.An analysis of variance and Kruskal-Wallis test were used to test the differences among the groups.RESULTS:The results showed that HXMM effectively increased amplitude of ERG of mice(P<0.05),alleviated fundus CNV leakage(P<0.05),and reduced the area of neovascularization and the expression of angiogenic proteins(P<0.05)after laser-induced CNV.CONCLUSION:HXMM can protect the retinal function of mice after laser-induced CNV,and inhibit the CNV development.
文摘In six healthy male subjects, the changes of respiratory airflow rate and heart rate were de-termined in sensory units of five just noticeable difference （JND） steps caused by inspiratory resistive （IR） loads ranging 0.28-1. 62 kPa.L<sup>-1</sup> s and physical stimuli in IR corresponding to JND steps andcombined resistance （CR） of different ratios equivalent to 2, 4 JND sensation at rest and duringmild and moderate muscular exercises (250 and 500 kgm·min<sup>-1</sup>) performed on a bicycle ergometer.The results suggest that the tendency of effects on respiratory pattern, within the test range of IRloads, are approximately consistent at rest and during mild and moderate exercise, that when theCR load is carried, the changes of respiratory pattern at rest and during mild exercise are similar,but more apparently during moderate exercise, and that the heart rote only increases with the rise ofexertion intensity, without apparent influence of resistive loads.
文摘The oil-soluble cadmium dipropyldithiophosphate additive was synthesized. A four-ball tester was used to evaluate the tribological performance of the additive in a mineral oil under different loads and lubricant grease synthesized compared with some commercial additives. The results show that it exhibits excellent antiwear and load-carrying capacities and is better than other additives. The surface analytical tools such as scanning electron microscope (SEM) with energy dispersive X-ray (EDX), X-ray photoelectron spectrometer (XPS) were used to investigate the topography, the compositions, and chemical states of some typical elements on the rubbing surface of worn scar.Smooth and light topography of worn scar further confirms that the additive shows good antiwear capacities. The results of EDX and XPS analyses indicate that tribochemical mixed protective films consisting of atomic cadmium, sulphides, sulphates and phosphates are formed on the rubbing surface, which contribute to improving the tribological properties of lubricant and grease. Particularly, the soft cadmium film formed plays an important role in improving antiwear properties of oils. Finally, antiwear mechanism of the additive and formation scheme of atomic cadmium was proposed.
基金supported by the National Natural Science Foundation of China,No.81600738the Youth Development Project of Air Force Medical University,No.21QNPY072(both to FF)。
文摘Retinal injury after blunt ocular trauma may directly affect prognosis and lead to vision loss.To investigate the pathological changes and molecular mechanisms involved in retinal injury after blunt ocular trauma,we established a weight drop injury model of blunt ocular trauma in male Beagle dogs.Hematoxylin-eosin staining,immunofluorescence staining,western blotting,and TUNEL assays were performed to investigate retinal injury within 14 days after blunt ocular trauma.Compared with the control group,the thicknesses of the inner and outer nuclear layers,as well as the number of retinal ganglion cells,gradually decreased within 14 days after injury.The number of bipolar cells in the inner nuclear layer began to decrease 1 day after injury,while the numbers of cholinergic and amacrine cells in the inner nuclear layer did not decrease until 7 days after injury.Moreover,retinal cell necroptosis increased with time after injury;it progressed from the ganglion cell layer to the outer nuclear layer.Visual electrophysiological findings indicated that visual impairment began on the first day after injury and worsened over time.Additionally,blunt ocular trauma induced nerve regeneration and Müller glial hyperplasia;it also resulted in the recruitment of microglia to the retina and polarization of those microglia to the M1 phenotype.These findings suggest that necroptosis plays an important role in exacerbating retinal injury after blunt ocular trauma via gliosis and neuroinflammation.Such a role has important implications for the development of therapeutic strategies.
基金Funded by the Key Program of Natural Science Foundation of China(20936007)the National Natural Science Foundation of China(51074153)the Major State Basic Research Development Program of China(2012CB215302)
文摘Organic-based materials are often used as the coating of metal oilcans. But they need to be sprayed several times in the whole life of oilcans because of the short-life of organic components. To overcome this problem, a type of long-life flexible cement-based anti-corrosion material used on the surface of metal oilcans was developed according to the principle that the steel reinforced concrete can remain the same life with buildings. The materials with different formulas composed of acrylic ~nulsion, cement and other additives were prepared. Because the ratios of polymer to cement played the decisive role in the adhesion and anti-corrosion characteristics, their effects on the physical performances were investigated by comparing the mechanical properties, anti-corrosion and anti-aging properties. The relationship between microstructure and macroscopic properties was also discussed.
基金Supported by the National Natural Science Foundation of China for Innovative Research Group(50921002)the Quartermaster Materials and Fuel Ministry of PLA Air Force Logistics Department(BKJ10C043)the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘The surface performances of directly fluorinated high density polyethylene （HDPE） are studied with Fourier transform infrared （FT-IR） spectra, scanning electron microscopy （SEM） and contact angle （CA） system. The SEM images show that there is a three-layer structure called the reaction, virgin and boundary layer structure. The depth of fluorinated layer is 5.75 ~m with 1 h fluorination time and 7.86 b^m with 2 h. The depths are 5.46 /~m and 5.07 /~m when fluorine density is 2G and 1~/0, respectively. CA indicates that the HDPE surface property becomes more hydrophobic with the increasing water contact angle from 78.5~ to 104.5~. Oleophobic and hydrophobic features of HDPE are identified by comparison of mass change experiments. It is shown that the in- crement rate of fluorinated HDPE is much lower than that of un-fluorinated HDPE filled in neither distilled water nor jet fuel.
基金Supported by Key Project of Medical Service Scientific Research of Navy Medical Center,No.20M2302.
文摘BACKGROUND Specific pulmonary infection could seriously threaten the health of pilots and their companions.The consequences are serious.We investigated the clinical diagnosis,treatment,and medical identification of specific pulmonary infections in naval pilots.CASE SUMMARY We analyzed the medical waiver and clinical data of four pilots with specific pulmonary infections,who had accepted treatment at the Naval Medical Center of Chinese People’s Liberation Army between January 2020 and November 2021,including three cases of tuberculosis and one of cryptococcal pneumonia.All cases underwent a series of comprehensive treatment courses.Three cases successfully obtained medical waiver for flight after being cured,while one was grounded after reaching the maximum flight life after being cured.CONCLUSION Chest computed tomography scanning should be used instead of chest radiography in pilots’physical examination.Most pilots with specific pulmonary infection can be cured and return to flight.
