A generator has been designed to generate simulating underpressure of blast wave and applied for the study of underpressure injuries on animals.The generator is composed of a vacuum pump,a hypotcnsive chamber,an experimental chamber,a membrane-rupturing device and a pressure-measuring system.Its operating principle is as follows:When the pressure of the hypotensive chamber is being decreased by the drawing of the vacuum pump to a given level .the membrane separating the hypotensive chamber and the experimental chamber is rapidly perforated by a sharp pointer.Underpressure occurs in the experimental chamber where the animal is fixed as soon as the pressure changes instantaneously.The range of the physical parameters of the simulated underpressure are -13 to -90 kPa for the peak level,1 ms to 90 ms for the decreasing time,and 14 ms to 2000 ms for the duration.Animal experimentation revealed that this device is capable of inflicting injuries and verified the possibility that the underpressure of blast waves can result in injuries.

Objective To analyze the clinical effect of the bone grafting pedicled with femoral quadratus for the osteonecrosis of femoral head.Methods The clinical operation data were analyzed from 355 patients with osteonecrosis of femoral head underwent by the surgery of the bone grafting pedicled with femoral quadrates in the First Affiliated Hospital of Zhengzhou University from August,2006 to June,2013.According to association research circulation osseous (ARCO) classifying,41,126,115,62,6 and 5 patients were in stage Ⅰ-C,Ⅱ-A,Ⅱ-B,Ⅱ-C,Ⅲ-A,and Ⅲ-B.The results were evaluated by the hundred forked method.Results All the patients obtained the outpatient followed-up after operation,the follow-up time was 1-8 (4.3 ± 1.8) years.The pain of the hip,the function of the joint,the motion of hip joint,and the X ray evaluation became better than preoperations.There were statistically significant differences in the healing time among all the age patients (P ＜ 0.05),along with the age growth,the healing time gradually extended.Compared with that before operation,the scores of all the stage patients after operation were higher (P ＜ 0.05).The rate of excellent and good results were 98.5％,98.0％,92.3％,89.7％,83.5％,81.3％ in stage Ⅰ-C,Ⅱ-A,Ⅱ-B,Ⅱ-C,Ⅲ-A,and Ⅲ-B,the excellent and good rate was 93.8％ of all the 355 patients.Conclusion Bone grafting pedicled with femoral quadratus is effective surgical method for the osteonecrosis of femoral head.

Objective To explore the application effect of sandwich teaching method in clini-cal teaching in the department of orthopedics. Methods Totally 150 clinical medicine students were divided into 2 groups: sandwich teaching group (n=75) and lecture-based learning group (n=75). Sandwich teaching method combined with bedside teaching method was used in sandwich teaching group while lecturing combined with bedside teaching method was used in control group. Theoretical examination, clinical operation skill test, clinical case analysis and questionnaire investigation were conducted after the course. Comparison between the two groups was made using independent sample t test and measurement data were expressed as x±s. P<0.05 signifies statistically significant differences. Results Theoretical examination score, clinical skill test score and clinical case analysis score were higher in sandwich teaching group than in control group. [(53.70±4.27) vs. (48.00±4.83);(15.70± 2.49) vs. (11.40±2.87);(17.10±1.52) vs. (13.80±1.32)]. Questionnaire showed that commutation and expression ability, cooperation ability and self thinking ability were better in sandwich teaching group than in control group , with statistical differences . Conclusions Sandwich teaching method achieves good teaching effect and it is worth recommending in clinical teaching.

Objective To investigate the potential mechanism of basic fibroblast growth factor (bFGF)-chitosan carrier to induce neural stem cells to differentiate into neurons. Methods After purification, the neural stem cells were cocultured with chitosan, soluble bFGF and bFGF-chitosan carrier. Three hours, twenty-four hours, three days and seven days after induction, immunofluorescence staining of Nestin, beta tubulin III, microtubule-associated protein-2 (MAP2), and fibroblast growth factor receptor 1 (FGFR1) were used to observe the expres-sion of FGFR1;real-time fluorescent quantitative polymerase chain reaction (qRT-PCR) and Western blotting were used to detect RNA and protein level changes after induction. Results Three hours after induction, there was no significant difference in the expression of FGFR1 among three groups. Twenty-four hours after induction, the expression level of FGFR1 was significantly higher in the bFGF-chitosan carrier group than in the chitosan group and the soluble bFGF group (P<0.001);three days and seven days after induction, the expression of FGFR1 decreased significantly in the chitosan group and soluble bFGF group (P<0.001), however, it was still higher in the bFGF-chitosan carrier group;moreover, the expression of genes associated with the pathway of extracellular regulated protein kinases/mitogen activated protein ki-nase (Erk/MAPK) was significantly higher in the bFGF-chitosan carrier group than in the chitosan group and soluble bFGF group (P<0.001). Conclusion bFGF-chitosan carrier might upregulate the expression of FGFR1, then activate Erk/MAPK signal pathways, and finally promote the differentiation of neural stem cells into neurons.

AIM:To study the effects of extracellular potassium on the protein expression of wild-type HERG and its mutant L539fs/47.METHODS:Wild-type HERG (WT) or its mutant HERG-L539fs/47 (MT) were transfected into HEK293 cells for 36 h.The cells were incubated in different media containing 0.8, 4.3 or 10 mmol/L potassium.Af-ter 6 h of incubation, the protein expression of HERG was detected by flow cytometry.After 12 h of incubation, the locali-zation and quantity of the proteins were detected by laser confocal imaging and Western blot.RESULTS: Different from the retention of mutant protein in cytoplasm, wild-type HERG protein was mainly distributed in the cell membrane.The 2 proteins both increased with the changes of extracellular potassium.Flow cytometry showed that the fluorescence in the 2 groups both increased with the changes of extracellular potassium ( P<0.01 ) .The fluorescence in WT group was signifi-cantly higher than that in MT group (P<0.01).Western blot showed that mutant HERG protein included only one 60 kD band, different from the 135 kD and 155 kD bands in wild-type HERG, which were affected by the changes of extracellular potassium (P<0.05).CONCLUSION:The retention of HERG mutant L539fs/47 protein in the cytoplasm is more than wild-type HERG.Chronic high extracellular potassium keeps the stability of wild-type and mutant HERG proteins on the cell membrane.Chronic low potassium reduces the expression of HERG channel proteins in a time-dependent manner.

OBJECTIVETo investigate the mechanism of drug-induced torsade de pointes (Tdp) in dogs.

METHODSIn arterially perfused canine left ventricular wedge preparations, the action potential duration (APD) of the endocardial (Endo), midmyocardial (M) and epicardial (Epi) myocytes, and transmural electrocardiogram (ECG) were recorded simultaneously. The effects of different concentrations of D-Sotalol on APD, transmural dispersion of repolarization (TDR), early after depolarization (EAD) and Tdp were observed.

RESULTSD-Sotalol prolonged APD of the Endo, M and Epi cells in a concentration-dependent manner from 0-100 µmol/L, and increased TDR due to a preferential APD prolongation of the M cells relative to Epi and Endo cells. The application of D-Sotalol elicited EAD, R on T ventricular premature beats, transmural reentry and Tdp in the M cells.

CONCLUSIONEAD and R on T ventricular premature beats induced by D-Sotalol in M cells triggers Tdp, which is maintained by TDR increment and transmural reentry.

Objective To evaluate the diagnostic value of ultrasound image features combined with cesarean section scores for placenta accreta . Methods A total of 151 pregnant women in the later trimester of pregnancy underwent two-dimensional and color Doppler ultrasonography . According to the results of the operation ,they were divided into the accreta group and the non-accreta group . The number of cesarean section and placental thickness in the two groups were recorded . The ultrasound image characteristics of the placenta previa ,the placenta posterior gap disappeared ,the placental lacuna in the placenta ,the muscle layer becoming thin or disappeared after the placenta ,the anatomical region of the uterus-bladder junction line and the abundant blood flow signal behind the placenta were compared between the two groups . Logistic regression analysis was performed according to the results of single factor analysis . After assigning the characteristics of the regression model ,the ROC curve was drawn to determine the best diagnostic intercept point . Results The presence of placenta previa ,placental lacuna and placental enriched blood flow signals combined with cesarean section scores were used to diagnose placenta accreta ,the area under the ROC curve was 0 .991 ,based the best cut-off point with 4 .5 ,the corresponding diagnostic sensitivity and specificity were 91 .1% and 100% ,respectively . Conclusions Ultrasound image features combined with cesarean section history scores have a high practical value in the diagnosis of placental accreta .

We used immobilized lipase from Candida sp. 99-125 to produce fatty acid methyl esters (FAMEs) from crude oil and methanol. We studied the effects of phospholipids on activity of immobilized lipase, reaction velocity, stability of immobilized lipase and the stability of immobilized lipase in crude and refined oil. Results showed that the activity of the lipase immersed in petroleum ether with 1% phospholipids dropped more quickly than the lipase in petroleum ether without phospholipids. When soybean oil was used without phospholipids as material, the FAMEs yield of 15 min was 26.2%, whereas the yield decreased to 12.4% when there were 5% phospholipids in the soybean oil. However when the phospholipids content was below 1%, the stability of the lipase did not change obviously. The lipase was stable when used to catalyze crude soybean oil and crude jatropha oil, after 10 cycles the FAMEs yield was still above 70%. This lipase showed great potential for industrial production of biodiesel from crude oil.
Biofuels ; analysis ; Candida ; enzymology ; metabolism ; Enzymes, Immobilized ; Fatty Acids ; metabolism ; Lipase ; metabolism ; Methanol ; metabolism ; Methyl Ethers ; metabolism ; Petroleum ; metabolism ; Phospholipids ; metabolism

Objective:To explore the application of microvascular flow imaging (MVFI) combined with high-frequency ultrasonography in children with haemophilic arthropathy A (HAA).Methods:Retrospective study.A total of 82 children diagnosed with HAA in the First Affiliated Hospital of Zhengzhou University from October 2018 to October 2020 were recruited.The elbow, knee and ankle joints of each child were examined by high-frequency ultrasonography.The numbers of thickened synovial joints were recorded.Blood flow signals of the thickening of synovial joints was checked by the MVFI and power Doppler ultrasound (PDUS), respectively.Color flow signals were graded by the semi-quantitative scoring systems.The chi- square test and independent multi-group ordinal multi-category rank-sum test were used to compare the differences of MVFI and PDUS in the display of thickened synovial blood flow. Results:A total of 254 joints were involved in 82 children with HAA, including synovial hypertrophy in 188 joints, hydrops articuli in 146 joints, fibrotic septa in 66 joints, cartilage damage in 63 joints, haemosider indeposition in 45 joints, bone erosion in 25 joints, osteophytes in 15 joints and bone remodeling in 8 joints.Grade Ⅱ synovial thickened joints were the most common.The proportion of blood flow signals detected by PDUS in thickened synovial membranes was significantly higher than that detected MVFI (52.66% vs.70.21%, χ2=12.225, P<0.05). Numbers of grade 0 and Ⅰ joints with thickened synovial membranes detected by MVFI were less than those of PDUS, while the opposite result was obtained in detecting grade Ⅱ and Ⅲ joints ( H=21.158, P<0.05). Compared with PDUS, MVFI more sensitively visualized the blood flow of the thickened synovial membrane. Conclusions:MVFI can more prominently detect the thickened synovial blood flow in children with HAA.A combined application of MVFI and high-frequency ultrasonography contributes to the evaluation of children with HAA.