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College students have gradually become the main force of entrepreneurship in mass entrepreneurship and innovation. However, their entrepreneurial performance was not as good as expected. We have carried out research to analyze the predictive factors of entrepreneurial performance of college students and put forward targeted suggestions, hoping to be helpful to improve their entrepreneurial performance of them. Based on questionnaire data obtained from 2,097 college student entrepreneurs, this study uses the structural equation model to analyze the predictive factors of the entrepreneurial performance of college students. The survey results of the questionnaire show that both personal and behavioral factors influence the entrepreneurial performance of college students. In this study, personal factors in this study mainly include entrepreneurial willingness, personality, and ability of entrepreneurs. Behavioral factors mainly refer to the positive behaviors of entrepreneurs that can affect entrepreneurial performance.
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Objective:To investigate the epidemiological characteristics of lower extremity deep vein thrombosis (DVT) in patients with femoral fracture.Methods:Retrospectively analyzed were the data of 2,571 patients with femoral fracture who had been treated at the Third Hospital of Hebei Medical University from January 2019 to December 2019. There were 1,079 males and 1,492 females, aged from 14 to 96 years (average, 67.1 years). There were 1,158 femoral neck fractures, 951 femoral intertrochanteric fractures, 309 femoral shaft fractures, and 153 femoral condylar fractures. 2,414 patients were treated surgically while 157 patients non-surgically. Color Doppler ultrasonography of both lower extremities was performed to determine the occurrence of DVT before operation and every week after operation for patients undergoing surgical treatment, and within 48 hours after admission and every week during hospitalization for those undergoing non-surgical treatment. The incidence and location of DVT were recorded for different femoral fractures.Results:The incidence of DVT in this cohort was 35.5%(913/2,517), that of proximal DVT 5.3%(135/2,571), and that of distal DVT 30.3% (778/2,571). In patients with femoral neck fracture, femoral intertrochanteric fracture, femoral shaft fracture and femoral condylar fracture, the incidence of DVT was respectively 28.8% (334/1,158), 44.7% (425/951), 30.7% (95/309) and 38.6% (59/153), the incidence of proximal DVT was respectively 2.7% (31/1,158), 5.6%(53/951), 9.7% (30/309) and 13.7% (21/153), and the incidence of distal DVT was respectively 26.2% (303/1,158), 39.1% (372/951), 21.0% (65/309) and 24.8%(38/153). The incidence of DVT in the femoral vein and above, popliteal vein, tibiofibular vein and intermuscular vein in this cohort was respectively 2.3%(60/2,571), 2.9%(75/2,571), 6.4%(165/2,571) and 23.8%(613/2,571).Conclusions:The incidence of DVT may be high in patients with femoral fracture, and the proximal DVT with a high risk of pulmonary embolism may occur more in patients with femoral condylar fracture.
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Objective:To observe the impacts of different postures on the hemodynamics of lower extremity vein.Methods:In this single center non-randomized controlled study in 15 healthy female volunteers, the hemodynamic changes in the common femoral vein were detected by color Doppler ultrasound at 10 different postures: supine position, slope positions with bed end elevated at 15°, 30° and 45°, trapezoidal positions with bed end elevated at 15°, 30° and 45°, and positions with bed head elevated at 30°, 45° and 60°.Results:Different postures resulted in significant differences in the velocity of blood flow in the common femoral vein ( P<0.05), with slope position at 45°> slope position at 30°> slope position at 15° = trapezoidal position at 30°> trapezoidal position at 15° = trapezoidal position at 45°> supine position> position with bed head elevated at 30°> position with bed head elevated at 45° = position with bed head elevated at 60°. Conclusions:In the postures observed in this study, the slope position with bed end elevated at 45° can promote the most effectively the blood reflux in the lower extremity vein, the trapezoidal positions with bed end elevated may not facilitate the distal blood reflux in the lower extremity vein, and positions with bed head elevated may hinder the blood reflux in the lower extremity vein.
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An ultrasensitive immunoassay was developed based on As3+ and Hg2+ labeled SiO2 @ Au nanoparticles signal tags and hydride generation-atomic fluorescence spectrometry (HG-AFS) for the detection of carcinoembryonic antigen(CEA) and carbohydrate antigen 19-9 (CA 19-9) respectively. Firstly, amino SiO2@ Au NPs were synthesized for selective absorption of As3+ and Hg2+ ions respectively. Subsequently,the secondary antibody (Ab2) of CEA and CA 19-9 was respectively labeled on As3+ or Hg2+-SiO2 @ Au NPs to prepare the corresponding signal tags for CEA and CA 19-9. Based on the sandwich immunoassay scheme, the tags, two antigen and corresponding first antibodies were bio-conjugated on the bottom of 96-well plate at room temperature to form the immunocomplex. After it was dissolved in alkali solution, As3+ and Hg2+ ions were released in solution and detected by HG-AFS, which concentration was proportional with logarithms of CEA and CA 19-9. The reaction conditions were optimized and the tags were characterized. This assay was based on determination of the concentration of As3+ and Hg2+ for quantization of the corresponding CEA and CA 19-9 antigen. The assay showed a wide linear range from 0. 001 to 100. 0 μg / L for CEA and 0. 01-80 U/ mL for CA 19-9, and a lower detection limit of 0. 5 ng / L and 0. 005 U/ mL respectively. This proposed method was used in real serums samples, the results were consistence with that by ELISA. The immunoassay showed three orders of magnitude of sensitivity lower than that of ELISA, which provides a promising simultaneous immunoassay for the early diagnosis of cancer .
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A child case of acute myocardial ischemia induced by symptomatic myocardial bridge (SMB)was reported and relevant literatures were reviewed in this article.The case and literatures indicate that myocardial bridge is a rare congenital coronary artery anomaly in children.The pathogenesis may be related to stenosis,spasm,arteriosclerosis of coronary artery because of myocardial bridge compression during systole.Clinical manifestations include chest pain,malignant arrhythmia,syncope,cardiac arrest and myocardial infarction.The diagnosis of myocardial bridge is based on cardiac imaging.SMB patients should be first treated with β-adrenergic; if ineffective,surgical treatment or implantable automated cardiac defibrillator shonld be chosen.The patients complicated with hypertrophic cardiomyopathy have worse conditions with high mortality.
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Objective To study the effect of Mycoplasma pneumoniae infection on the coagulation system in children and to clarify its mechanism in order to guide the therapeutic strategy for Mycoplasma pneumoniae infection in clinical practice.Methods A prospective and case control study was carried out in 36 children with Mycoplasma pneumoniae infection in Weifang People ' s Hospital from January through December in 2011.The 36 patients were divided into two groups according to the MP-IgM plasma titers,namely low-titer group with MP-IgM 1 ∶ 80-1 ∶ 160 (n =17) and high-titer group with MP-IgM 1 ∶ 320-1 ∶1280 (n =19).The subjects of control group (n =20) were recruited from healthy children as they took routine physical examination during the same period.Six indexes related to the coagulation function as well as D-dimer in plasma were determined.All data were analyzed by using SPSS 15.0 software.Results The levels of fibrinogen (FIB) and D-dimer in the low-titer group and high-titer group were significantly higher than those in the control group (P < 0.05).The prothrombin (PT) and activated partial thromboplastin time (APTT) in the high-titer group were significantly shorter than those in the control group respectively (P < 0.05).Conclusions Mycoplasma pneumoniae infection in children gives rise to the potential for activating the extrinsic and intrinsic coagulation system,promoting thrombosis and in turn inducing ischemic stroke in serious cases.
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BACKGROUND:Early clinical application of non-biological materials (bone cement) for treatment of hip joint is ineffective, due to the large fixed range, long fixation time, as wel as aging and rupture of bone cement interface causing complications such as prosthetic loosening. Thus, postoperative range of motion of the hip joint can be affected to some degree. OBJECTIVE:To investigate the methods and progress of biological and non-biological materials for total hip replacement and to assess the features and clinical application of different hip prostheses. METHODS:A computer-based search of PubMed and CNKI was performed by the first author to retrieve articles related to biological materials and tissue-engineered hip joint using the keywords of“carpal bone, fracture ununited”in the title and abstract. The keywords were limited to Chinese and English. RESULTS AND CONCLUSION:Biological materials for internal fixation have good wear resistance, corrosion resistance and biocompatibility. Currently, the combination of metal joint head and polyethylene acetabulum with ultrahigh molecular weight is the most commonly used in hip replacement. However, the metal joint head exhibits an elastic modulus far from the human skeleton, resulting in stress shielding effects which are easy to cause prosthetic loosening and instability. Bio-inert ceramics has high in vivo stability and good mechanical strength;and bioactive ceramics has bone conduction characteristics and performance of the living bone integration. Composite prosthesis, because of adjustable elastic modulus and sufficient mechanical strength, shows the mechanical properties close to the human bone and has been gradual y noticed. However, there is a lack of ideal prostheses with good biocompatibility and biomechanics. Therefore, hip design and manufacturing processes should be improved to elevate wear resistance and mechanical properties, to enhance the binding between prosthesis and the host bone, and to reduce stress shielding in order to improve the biocompatibility of the implant with the host, and extend the prosthetic life.
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BACKGROUND:Few reports are found about the effect of ovariectomized rats' bone histomorphometry parameters using non-destructive dynamic loading system.OBJECTIVE:To observe the effect of different loads situations on the bone histomorphometry parameters in ovariectomized rats.DESIGN,TIME AND SETTING:A controlled observation on the bone histomorphometry was performed in the Biomedical Engineering Laboratory of Jilin University from April 2007 to August 2007.MATERIALS:A total of 35 9-month-old Sprague-Dawley female rats were randomly divided into five groups,including sham operation group,ovariectomized (OVX) control group,OVX loading 1 N group,OVX loading 2 N group,OVX loading 4 N group.There were 7 rats in each group.METHODS:Rats in OVX control group and castration load group were processed into bilateral OVX on the back. The sham operation group only underwent the excision of fat tissues on back,and then sutured. After castration for 1 week,rats were loaded with non-destructive dynamic loading system in the two sides of the tibia,15 minutes a day. The mechanical loads would continue for 4 weeks and the loads were 1N,2N and 4N.MAIN OUTCOME MEASURES:Changes of proximal tibia bone histomorphometry parameters.RESULTS:The area,number and thickness of trabecular bone in OVX loading group were all higher than OVX control group (P<0.05,P<0.01).The trabecular bone area and thickness in OVX 4 N and OVX 2 N groups were significantly higher than OVX control group (P < 0.001).There was a downward trend of trabecular separation in OVX 4 N group compared with OVX control group (P < 0.05). With the increasing loads,there was an increasing trend of the area,number and thickness of trabecular bone,which were close to sham-operated group. The trabecular separation was declined. Single fluorescent labeled surface and double fluorescent labeled surfaces in sham operated group were all lower than that in OVX control group. With the increase in loads,the single fluorescent labeled surface,double fluorescent labeled surface,interlabeled width and mineral apposition rate had been shown to increase. The OVX 2 N and OVX 4 N groups exhibited a remarkably higher level of mineral apposition rate than OVX control group (P < 0.05).CONCLUSION:With the increase in load at the range of 1-4 N,all parameters of bone histomorphometry improve in the OVX rats,the bone microstrcture is greatly ameliorated,bone mass loss is reduced and the process of osteoporosis is delayed.
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Objective To investigate the chemical constituents in Desmodium blandum and their antitumor bioactivity.Methods Various chromatographic techniques were employed for the isolation and purification of the constituents by butanol at 50 ℃ including silica gel, Sephadex LH-20.The compounds structures were elucidated by spectral analyses(IR,UV,NMR,and MS).Then their cytotoxic activity was studied.Results They were identified as N,N-dimethyltryptamine (Ⅰ),5-methoxy-N,N-dimethyltryptamine(Ⅱ),citrusinol(Ⅲ),yukovanol(Ⅳ),(Z)-1-(4-hydroxy-2,3-dimethoxyphenyl)-3-(4-hydroxyphenyl) propene(Ⅴ),(Z)-1-(3-hydroxy-2,4-dimethoxy phenyl)-3-(4-hydroxy-3-methoxy-phenyl) propene(Ⅵ),methyl protocatechuate(Ⅶ),katuranin(Ⅷ).Conclusion Eight compounds are isolated from the stems of D.blandum for the first time.In the MTT antitumor experiments,compounds Ⅰ and Ⅲ—Ⅵ have the cytotoxic activity to KB cell.