With the rapid development of aviation technology,the ability of pilots to fly successfully and safely has attracted much attention.Improving pilots'emergency evacuation capabilities is the responsibility of every aviation worker.The injury caused by pilot parachute jumping is an important issue in flight safety.During the parachute jumping process,the pilot will be subjected to various impact forces and aerodynamic forces,which can cause damage to the pilot's spine,nervous system,circulatory system,and multiple parts of the body,and even endanger lift.This article focuses on exploring the characteristics of pilot ejection parachute injuries,categorizing and summarizing them according to the location and factors of the injuries,and analyzing their protective strategies.Targeted ground ejection simulation training is conducted for pilots in different batches to improve the combat effectiveness of the armies.

Objective:To investigate the interventional and protective effect of low-dose L-carnitine(LC)against reproductive system damage in male Wistar rats during acute exposure to simulated high-altitude environment.Methods:A total of 24 specific pathogen-free male Wistar rats,aged 12 weeks,were randomly divided into control group,high-altitude model group,and LC intervention group[intraperitoneal injection of LC at a dose of 50 mg/(kg·d)],with 8 rats in each group.The rats in the control group were fed under normal conditions(at an altitude of approximately 1 500 m),those in the high-altitude model group,and those in the LC intervention group were fed in a hypobaric oxygen chamber(at a simulated alti-tude of 6 000 m).The rats were sacrificed after 3 days.The testis was collected to calculate testicular index;the semen was collected from the epididymis,and the Weili sperm quality analysis system was used to assess sperm quality;blood samples were collected from the abdominal aorta,and ELISA kits were used to measure the serum levels of testosterone(T),luteinizing hormone(LH),and follicle-stimulating hormone(FSH);testicular tissue samples were collected,and biochemical kits were used to measure the activity of reactive oxygen species(ROS),malondialdehyde(MDA),and superoxide dismutase(SOD);testicular tissue was collected to prepare HE and electron microscopy sections,and a light microscope and a transmission electron microscope were used for observation.Results:Com-pared with the blank control group,the high-altitude model group had significant increases in the levels of T,LH,and FSH(P<0.01),testicular tissue damage under the light microscope,and changes in the morphology of spermatogenic cells,including mitochondrial al-terations,membrane edema,loss of cristae,swelling of the matrix,and local dissolution,as well as significant increases in the levels of ROS and MDA(P<0.01)and a significant reduction in SOD activity(P<0.01).Compared with the high-altitude model group,the LC intervention group had a significant increase in the level of T(P<0.01),significant reductions in the levels of FSH and LH(P<0.01),and significant improvements in the pathological changes of testicular tissue,with no marked mitochondrial injury,and there were sig-nificant reductions in the levels of ROS and MDA(P<0.01)and a significant increase in SOD activity(P<0.01).There was no signifi-cant difference in testicular index between groups(P>0.05).The high-altitude model group had a significantly lower sperm count than the blank control group(P<0.05),while there was no significant difference in sperm count between the LC intervention group and the blank control group(P>0.05);there was no significant difference in sperm motility between groups(P>0.05).Conclusion:Low-dose LC can improve reproductive system damage in rats during acute exposure to simulated high-altitude environment,possibly by alleviat-ing oxidative stress response.

OBJECTIVE: To investigate the efficacy of minimally invasive osteotomy with preservation of blood supply to the transversely transported bone segment in the treatment of chronic ischemic lower limb diseases using tibial transverse bone transport. METHODS: A retrospective analysis was conducted on the clinical data of 12 patients with chronic ischemic lower limb diseases who met the selection criteria and were treated between June 2016 and December 2023. The cohort included 7 males and 5 females, aged 26-87 years (mean, 61.2 years). Among them, 7 patients had diabetic foot (DF), including 2 cases complicated by arteriosclerosis obliterans (ASO), with a DF duration ranging from 1.7 to 23.0 months (mean, 9.6 months) and ulcer sizes ranging from 3.2 cm×2.4 cm to 10.0 cm×6.6 cm. Three patients had ASO with a disease duration of 1.7-23.0 months (mean, 10.4 months) and ulcer or post-amputation wound sizes ranging from 2.2 cm×2.1 cm to 12.0 cm×7.7 cm. Additionally, 2 patients with thromboangiitis obliterans (TAO) had a disease duration of 7 and 12 months, respectively. Preoperatively, the mean foot skin temperature was (27.63±0.34)℃, and the visual analogue scale (VAS) score was 8.5±0.7. All patients underwent tibial transverse bone transport using minimally invasive osteotomy while preserving the blood supply to the transported bone segment. Postoperative complications and foot ulcer healing were observed. The effectiveness of tibial transverse bone transport was evaluated by comparing preoperative and postoperative foot skin temperature, VAS scores, as well as through CT angiography (CTA). RESULTS: One DF patient with ASO was lost to follow-up, while the remaining 11 patients were followed up 10-29 months (mean, 20.5 months). One DF patient had a displaced fracture at the site of tibial transport due to trauma, which healed after plaster immobilization; 1 DF patient had a small amount of pigmentation in the skin of the donor site, but the blood circulation was good; no complication such as pin tract infection, skin necrosis, or osteomyelitis occurred in the donor site of all patients. At 2-3 weeks postoperatively, the foot skin temperature was (34.21±0.65)℃, and the VAS score was 0.3±0.1, both significantly improved compared to preoperative ones ( t=-31.578, P<0.001; t=49.000, P<0.001). Two TAO patients experienced recurrent, persistent, intolerable pain at 7-10 days postoperatively, with no reduction in ulcer size or necrotic areas; 1 underwent toe amputation, and the other required a mid-leg amputation. The remaining patients achieved complete ulcer healing, with healing time ranging from 5.1 to 9.2 weeks (mean, 6.8 weeks). CTA showed no new vascular occlusions or embolisms. X-ray films at 4 months postoperatively demonstrated proper repositioning and good healing of the transported tibial bone segment. CONCLUSION The application of minimally invasive osteotomy with preserved blood supply to the transversely transported bone segment in tibial transverse bone transport for the treatment of chronic ischemic lower limb diseases effectively minimizes extensive soft tissue dissection, reduces surgical soft tissue damage, and better maintains local blood supply. This approach lowers the risk of postoperative infection and skin necrosis while accelerating postoperative recovery.
Humans ; Osteotomy/methods* ; Middle Aged ; Male ; Female ; Aged ; Tibia/surgery* ; Minimally Invasive Surgical Procedures/methods* ; Retrospective Studies ; Adult ; Bone Transplantation/methods* ; Aged, 80 and over ; Diabetic Foot/surgery* ; Treatment Outcome ; Arteriosclerosis Obliterans/surgery* ; Ischemia/surgery* ; Lower Extremity/blood supply*

OBJECTIVE: To explore the method and effectiveness of index finger proximal dorsal island flap supplied by the nutrient vessels of superficial branch of radial nerve for treatment of thumb skin and soft tissue defect. METHODS: Between August 2019 and December 2024, 12 patients with thumb skin and soft tissue defects caused by trauma accompanied by variation of the first dorsal metacarpal artery were treated. There were 8 males and 4 females, aged 19-55 years, with an average age of 32 years. The wound area ranged from 2.2 cm×2.0 cm to 5.5 cm×3.5 cm. The time from injury to operation ranged from 1.5 to 6.0 hours, with an average of 4.5 hours. After thorough debridement, the wound was repaired with a index finger proximal dorsal island flap supplied by the nutrient vessels of the superficial branch of the radial nerve. The flap area ranged from 2.4 cm×2.2 cm to 6.0 cm×4.0 cm. The donor site was repaired with free skin grafting. Regular follow-up was conducted postoperatively to observe the appearance, texture, sensory recovery of the flap, and the condition of the donor site. RESULTS: The operation time ranged from 30 to 72 minutes, with an average of 47 minutes; intraoperative blood loss ranged from 30 to 70 mL, with an average of 46 mL. After operation, partial necrosis occurred at the skin edge of the radial incision on the dorsum of the hand in 1 case, which healed after dressing changes; all other flaps survived uneventfully, with primary wound healing. The skin grafts at the donor sites all survived. All 12 patients were followed up 5-36 months, with an average of 14 months. The appearance and texture of the flaps were good. At last follow-up, the two-point discrimination of the flaps ranged from 4 to 9 mm, with an average of 5.2 mm. According to the functional evaluation criteria for upper limb issued by the Hand Surgery Society of Chinese Medical Association, the results were excellent in 11 cases and good in 1 case. No scar contracture, pain, or joint movement limitation was observed at the donor sites. CONCLUSION For patients with skin and soft tissue defects of the thumb accompanied by variation of the first dorsal metacarpal artery, the index finger proximal dorsal island flap supplied by the nutrient vessels of the superficial branch of the radial nerve can be selected. This method has advantages such as shorter operation time, less intraoperative bleeding, and good postoperative appearance and sensation of the flap.
Humans ; Male ; Adult ; Female ; Thumb/surgery* ; Soft Tissue Injuries/surgery* ; Radial Nerve/surgery* ; Middle Aged ; Surgical Flaps/innervation* ; Plastic Surgery Procedures/methods* ; Skin Transplantation/methods* ; Young Adult ; Treatment Outcome ; Fingers/surgery* ; Skin/injuries*

Objective A new type fighter pilot's helmet comfort was investigated to provide basis for generalization and popularization.Methods A quantitative questionnaire was designed to evaluate the comfort of current helmets and new helmets by pilots of series A and B fighters,and compare the new helmets with the current helmets.Thirdly,quantitative statistics of questionnaires were carried out to analyze the pilot's opinions on current helmets and new helmets.Based on the structure and quality characteristics of current helmets and new helmets,the investigation results were analyzed and discussed.Results A total of 167 pilots from series A and B fighter aircraft participated in trial wear and questionnaire investigation of new helmets.Among them,103 pilots from series A fighters and 64 pilots from series B fighters.Compared with the pilot's current helmet,the new helmet is lightweight and comfortable.Among them,92.2%of the pilots of the series A believe that the new helmet is more comfortable than the current helmet,and 90.3%of pilots think it is necessary to replace the current helmet with the new helmet.90.6%of the pilots of the Series B think the new helmet is more comfortable than the current helmet,and 92.2%of pilots think it is necessary to replace the current helmet with the new helmet.Conclusion The new fighter pilot's helmet is light and comfortable,and has been widely praised by pilots.The research results provide data support and decision-making basis for its universalization and popularization.

BACKGROUND:Exosomes derived from human umbilical cord mesenchymal stem cells are widely used for bone repair and reconstruction,significantly enhancing osteogenesis and promoting angiogenesis.OBJECTIVE:To explore the mechanisms of exosomes derived from human umbilical cord mesenchymal stem cells in the treatment of osteoporotic fractures.METHODS:H uman umbilical cord mesenchymal stem cells were extracted using tissue block culture method.Exosomes derived from human umbilical cord mesenchymal stem cells were extracted using ultracentrifugation method for identification.Thirty 12-week-old female SD rats were randomly divided into sham-operated group(n=6)and ovariectomized group(n=24).Osteoporosis model was established by castration in the ovariectomized group.12 weeks after modeling,6 rats in the ovariectomized group and 6 rats in the sham-operated group were randomly selected for Micro-CT and hematoxylin-eosin staining to verify the models.After verification,the remaining 18 rats in the ovariectomized group were randomly assigned to three groups to establish osteoporotic fracture models.The fracture end was separately injected with PBS(PBS group),exosomes at 1.5×1011 particles/mL(low-concentration exosome group),and 3×1011 particles/mL(high-concentration exosome group).Four weeks after operation,fracture healing and bone angiogenesis were evaluated by imaging and histological observations.RESULTS AND CONCLUSION:(1)In the gross specimens,compared with the PBS group,the exosome group had faster fracture healing and more callus formation.(2)The X-ray score of fracture healing in the exosome group was significantly higher than that in the PBS group,and the difference was significant(P＜0.05).(3)Micro-CT three-dimensional imaging:Compared with the PBS group,the fracture healing in the exosome group was accelerated and the callus formation was significantly increased;the bone volume fraction in the exosome group was significantly higher than that in the PBS group,and the difference was significant(P＜0.01).(4)Hematoxylin-eosin staining and Masson's trichrome staining showed that bone trabeculae and the new bone tissue in the exosome group were more than those in the PBS group.(5)Immunohistochemical staining showed that the expression of CD31 and osteocalcin in the exosome group was significantly higher than that in the PBS group.The high-concentration exosome group had a higher density of new blood vessels,more callus formation,and faster fracture healing than the low-concentration exosome group,showing a concentration-dependent manner.The results show that exosomes derived from human umbilical cord mesenchymal stem cells can promote the repair of osteoporotic fracture by enhancing the angiogenesis and osteogenesis.The mechanism may be related to the increased expression of CD31 and osteocalcin.

BACKGROUND:Exosomes derived from human umbilical cord mesenchymal stem cells are widely used for bone repair and reconstruction,significantly enhancing osteogenesis and promoting angiogenesis.OBJECTIVE:To explore the mechanisms of exosomes derived from human umbilical cord mesenchymal stem cells in the treatment of osteoporotic fractures.METHODS:H uman umbilical cord mesenchymal stem cells were extracted using tissue block culture method.Exosomes derived from human umbilical cord mesenchymal stem cells were extracted using ultracentrifugation method for identification.Thirty 12-week-old female SD rats were randomly divided into sham-operated group(n=6)and ovariectomized group(n=24).Osteoporosis model was established by castration in the ovariectomized group.12 weeks after modeling,6 rats in the ovariectomized group and 6 rats in the sham-operated group were randomly selected for Micro-CT and hematoxylin-eosin staining to verify the models.After verification,the remaining 18 rats in the ovariectomized group were randomly assigned to three groups to establish osteoporotic fracture models.The fracture end was separately injected with PBS(PBS group),exosomes at 1.5×1011 particles/mL(low-concentration exosome group),and 3×1011 particles/mL(high-concentration exosome group).Four weeks after operation,fracture healing and bone angiogenesis were evaluated by imaging and histological observations.RESULTS AND CONCLUSION:(1)In the gross specimens,compared with the PBS group,the exosome group had faster fracture healing and more callus formation.(2)The X-ray score of fracture healing in the exosome group was significantly higher than that in the PBS group,and the difference was significant(P＜0.05).(3)Micro-CT three-dimensional imaging:Compared with the PBS group,the fracture healing in the exosome group was accelerated and the callus formation was significantly increased;the bone volume fraction in the exosome group was significantly higher than that in the PBS group,and the difference was significant(P＜0.01).(4)Hematoxylin-eosin staining and Masson's trichrome staining showed that bone trabeculae and the new bone tissue in the exosome group were more than those in the PBS group.(5)Immunohistochemical staining showed that the expression of CD31 and osteocalcin in the exosome group was significantly higher than that in the PBS group.The high-concentration exosome group had a higher density of new blood vessels,more callus formation,and faster fracture healing than the low-concentration exosome group,showing a concentration-dependent manner.The results show that exosomes derived from human umbilical cord mesenchymal stem cells can promote the repair of osteoporotic fracture by enhancing the angiogenesis and osteogenesis.The mechanism may be related to the increased expression of CD31 and osteocalcin.

Objective: To investigate the effects of plateau environment exposure on the reproductive system of male rats, so as to provide the reference for mechanisms of reproductive damage in plateau environment. Methods: Sixty SPF-grade 12-week-old male Wistar rats were randomly divided into the plain-exposed group, the 1 day-, 3 day-, 7 day-, 14 day- and 28 day- plateau-exposed groups. The rats in the plain-exposed group were raised under normal conditions for 28 days, while the rats in the plateau-exposed groups were raised in a simulated high-altitude plateau chamber. After the completion of the designated feeding periods, the rats were sacrificed under anesthesia, and testicular tissue and abdominal aortic blood were collected to detect the testicular index and evaluate sperm quality. Histological and cellular morphologies of the testicular tissue were analyzed. Additionally, the levels of malondialdehyde (MDA), superoxide dismutase (SOD) and reactive oxygen (ROS) in the testicular tissue were determined, along with serum levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH) and testosterone (T). Conclusions Plateau environment may cause a decrease in testicular index and sperm quality, impair mitochondrial function, induce oxidative stress, and thus affect reproductive system of male rats. However, there are signs of self-repair in the reproductive system with the increase of exposure duration.

Trials within cohorts （TwiCs） are design methods derived from randomized controlled trials （RCTS）. They have been widely used in chronic disease areas such as tumors and cardiovascular diseases. The basis of the TwiCs design is a prospective cohort of specific diseases. When RCTS need to be implemented， some patients meeting the inclusion and exclusion criteria are randomly sampled from the cohort to receive "trial interventions"， while the remaining patients in the cohort who meet the inclusion and exclusion criteria continue to receive conventional treatment as control groups. By comparing the efficacy differences between the intervention measures of the trial group and the control group， the efficacy of intervention measures was evaluated. Within the cohort， the same process could be repeated to carry out multiple RCTS， so as to evaluate different intervention measures or compare the efficacy of different doses or timing of interventions. Compared with classical RCTS， TwiCs make it easier to recruit patients from the cohort and have higher external validity， providing a new research paradigm for improving the efficiency and applicability of RCTS in clinical practice. However， TwiCs may also face the challenge of poor compliance of patients in the cohort. Researchers need to take effective measures to control these patients in the design and operation of TwiCs. This article focused on the methodological key points during the implementation of TwiCs， including multi-stage informed consent （patients are informed of consent at three stages： entering the cohort， entering the trial group， and after the trial）， randomization procedures （only random sampling of patients from the cohort to receive "trial interventions"）， sample size calculation， and statistical analysis methods. The article also compared the differences between TwiCs and traditional RCTS and illustrated TwiCs research design and analysis with examples， so as to provide new research ideas and methods for clinical researchers.

Objective To observe the clinical efficacy and safety of lupatadine tablets combined with azelastine hydrochloride nasal spray in the treatment of allergic rhinitis patients.Methods Patients with allergic rhinitis were randomly divided into control group and treatment group.Both groups received general treatment.On this basis,the control group was given azelastine hydrochloride nasal spray 0.14 mg per nostril each time,bid;on the basis of control group,the treatment group received lupatadine tablets 10 mg each time,orally,qd.Two groups were treated for 4 weeks.The clinical efficacy,rhinoconjunctivitis related quality of life questionnaire(RQLQ),serum indexes[interleukin-6(IL-6),IL-1 β,tumor necrosis factor-α(TNF-α),immunoglobulin E(IgE)]and safety were compared between the two groups.Results Treatment group were enrolled 53 cases,4 cases dropped out,and 49 cases were finally included in the statistical analysis.Control group were enrolled 53 cases,4 cases dropped out,and 49 cases were finally included in the statistical analysis.After treatment,the total effective rates of the treatment and control groups were 95.92％(47 cases/49 cases)and 81.63％(40 cases/49 cases)with significant difference(P＜0.05).After treatment,the RQLQ scores of treatment and control groups were(49.57±6.97)and(58.18±7.78)points,IL-6 levels were(5.12±1.25)and(7.34±1.46)ng·L-1,IL-1 β levels were(12.25±5.64)and(20.05±6.32)pg·mL-1,TNF-α levels were(3.25±0.62)and(4.45±0.49)pg·mL-1,the IgE levels were(114.28±19.63)and(136.84±30.14)μg·L-1,respectively,the differences were statistically significant difference(all P＜0.05).The adverse drug reactions of two groups were dry mouth,fatigue,dizziness and drowsiness.The total incidences of adverse drug reactions in the treatment and control groups were 16.33％and 10.20％without significant difference(P＞0.05).Conclusion Lupatadine tablets combined with azostine hydrochloride nasal spray have a definitive clinical efficacy in the treatment of allergic rhinitis patients,which can effectively reduce the inflammatory reaction,reduce the IgE levels,improve the quality of life,without increasing the incidence of adverse drug reactions.