BACKGROUND:Choosing internal fixator implants with good strength and stiffness is the key to repair femoral neck combined with ipsilateral subtrochanteric fractures. OBJECTIVE:To compare the biomechanical properties of different implant fixation for femoral neck combined with ipsilateral subtrochanteric fractures. METHODS:Totaly 24 adult antiseptic cadaver specimens were used to produce fracture models with femoral neck fracture combined with 5 cm of ipsilateral subtrochanteri medical cortical defect, and were divided into femoral proximal locking plate group, lengthening proximal femur anti-rotation intramedulary nail group and lengthening proximal femoral nail group according to the random number table method. The results of axial compression test, torsion test and axial compression failure rest in three groups were compared. RESULTS AND CONCLUSION: The axial compressive stiffness and failure load in lengthening proximal femur anti-rotation intramedulary nail group were significantly greater than those in femoral proximal locking plate group and lengthening proximal femoral nail group, and those in lengthening proximal femoral nail group were significantly greater than those in femoral proximal locking plate group (P < 0.05). The torsional stiffness in femoral proximal locking plate group was significantly greater than that in lengthening proximal femur anti-rotation intramedulary nail group and lengthening proximal femoral nail group, and that in lengthening proximal femur anti-rotation intramedulary nail group was significantly greater than that in lengthening proximal femoral nail group (P < 0.05). The indexes of biomechanical properties of specimens at the 4thand 8th weeks after fixation in three groups were slightly increased compared with those in 0 week after surgery, but the difference was no statisticaly significant (P > 0.05). These results demonstrate that to a certain extent, compared with the femoral proximal locking plate and lengthening lengthening proximal femoral nail, lengthening proximal femur anti-rotation intramedulary nail fixation for repair of femoral neck combined with ipsilateral subtrochanteric fractures has more biomechanical advantages.

Research of co-authorship network can reveal the scientific research collaboration network and can thus help us to have an understanding of it. Graphic database and Neo4J were described in detail due to the limitations of relationship database in processing the data of co-authorship network. Graphic database Neo4J-based research and practice of co-authorship network were analyzed with the Institutional Knowledge System of AMMS that we were involved in its construction as an example, and the advantages of Neo4J-based co-authorship network were summarized.

Objective To analyze the similarities and differences between four-point hand-knee position and hand-foot kneeling positions in trunk muscle activation and co-contraction, explore the possibility of hand-foot kneeling position as core stabilization exercises, so as to provide suggestions for actual training.Methods Nineteen healthy volunteers randomly performed exercises of four-point hand-knee position (4 motions) and hand-foot kneeling position (3 motions), while surface electromyography (sEMG) signals were collected from bilateral rectus abdominis, external oblique, erector spine, and multifidus muscles. The average sEMG and muscle co-contraction index (CCI) based on the sEMG signals were analyzed and compared.Results Significant differences were found in the sEMG and CCI within and between the two positions. Under four-point hand-knee position with the right hand and left leg lifting, the activation of all muscles was higher than that in the starting position. In four-point hand-knee position with the left leg lifting, the activation of ipsilateral multifidus muscle was significantly higher than that in hand-foot kneeling position. The activation degree of external oblique muscle and rectus abdominis was higher in hand-foot kneeling position with right hand lifting. A total of 28 muscle matching methods were obtained by pair-to-pair matching of 8 muscles. The starting posture in four-point hand-knee position fluctuated the least, indicating that the spine was the most stable, while the index of other exercises fluctuated in a larger range.Conclusions The possibility of hand-foot kneeling position as core stabilization exercises was proved from two aspects, namely, muscle activation and CCI. The hand-foot kneeling position and four-point hand-knee position can be used for strengthening abdominal muscles and back muscles, respectively. The four-point hand-knee position with contralateral upper and lower limbs lift is a more advanced exercise for trunk muscles, but sports injuries should be avoided.

Denitrification is an indispensable part of most sewage treatment systems. The biological denitrification process has attracted much attention in the past decades due to the advantages such as cost-effectiveness, process simplicity, and absence of secondary pollution. This review summarized the advances on biological denitrification processes in recent years according to the different physiological characteristics and denitrification mechanisms of denitrification microorganisms. The pros and cons of different biological denitrification processes developed based on nitrifying bacteria, denitrifying bacteria, and anaerobic ammonia-oxidizing bacteria were compared with the aim to identify the best strategy for denitrification in a complex wastewater environment. The rapid development of synthetic biology provides possibilities to develop highly-efficient denitrifying strains based on mechanistic understandings. Combined with the applications of automatic simulation to obtain the optimal denitrification conditions, cost-effective and highly-efficient denitrification processed can be envisioned in the foreseeable future.
Aerobiosis ; Denitrification ; Nitrification ; Nitrogen ; Waste Water

【Objective】 To investigate the effects of 80 kVp combined with multi-model adaptive statistical iterative reconstruction algorithm （ASiR-V） on the image quality of CT angiography （CTA） of iliac artery in kidney transplantation candidates before operation. 【Methods】 Totally 50 kidney transplantation candidates underwent “one-stop” scanning combined CTA for coronary and iliac arteries were recruited consecutively. After the scanning， images were reconstructed with different ASiR-V levels on the iliac artery from 50% to 100% at a 10% interval， and 6 groups of images were obtained. We evaluated and compared all image qualities， DLP and CTDI in the patients’ examination were recorded， and the effective dose （ED） was calculated. 【Results】 All of the image quality objective scores of different ASiR-V levels on the iliac artery were above 3 points （3.32±0.24）， and the average CT value was （344.30±74.53）HU. The ED received by the patient throughout the examination was （2.71±0.42)mSv. The image noise decreased while SNR and CNR increased monotonically as the ASiR-V levels increased， among which 80% ASiR-V image quality score was the highest with 3.41±0.26. 【Conclusion】 For patients who need to have both coronary and iliac arteries evaluated before kidney transplantation operation， low tube voltage （80 kVp） combined with 80% ASiR-V can obtain high-quality iliac artery images under the premise of reducing the ED dose， which can provide practical basis for further reducing the dose in personalized scanning scheme for such patients. It has good feasibility and clinical application value.

OBJECTIVE：To investigate the clini cal features of thrombocytopenia induced by antidepressants ，and to provide reference for the rational use of clinical drugs. METHODS ：Retrieved from CNKI ，Wanfang database ，VIP，PubMed and Web of Science，during Jan. 1st in 1985 to Aug. 31st in 2020，case reports about antidepressants-induced thrombocytopenia was collected and analyzed descriptively in terms of demographic characteristics ，medication，clinical manifestations ，treatment and outcome. RESULTS：A total of 17 literatures were retrieved ，and 19 patients were included ，involving 10 male and 9 female，aged from 5 to 95 years old ，with an average of （48±24）years old. Nine kinds of drugs were involved ，including 4 cases of escitalopram ，3 cases of citalopram ，3 cases of fluoxetine ，3 cases of mirtazapine ，2 cases of amitriptyline ，1 case of sertraline ，1 case of paroxetine，1 case of mianserin and 1 case of imipramine. There were 9 cases of single drug and 10 cases of drug combination. All 19 patients suffered from thrombocytopenia at 3 d-10 years after medication ，14 of them had hemorrhage tendency. Main clinical manifestations included mucocutaneous hemorrhage ，gingival bleeding ，black stool ，hematochezia，vaginal bleeding ，ocular hemorrhage，alveolar hemorrhage. No bleeding was found in 5 cases. After drug withdrawal/changing drugs and other symptomatic treatment， platelet count of 19 patients recovered to normal ， and bleeding symptoms disappeared. CONCLUSIONS ： Thrombocytopenia caused by antidepressants has no obvious clinical features and is not easy to be found ，but it may lead to severe； bleeding symptoms if it is not found in time. The changes of platelet count should be closely monitored in clinical application of such drugs to ensure the safety of drug use.