Objective:To construct and validate the best predictive model for 28-day death risk in patients with septic shock based on different supervised machine learning algorithms.Methods:The patients with septic shock meeting the Sepsis-3 criteria were selected from Medical Information Mart for Intensive Care-Ⅳ v2.0 (MIMIC-Ⅳ v2.0). According to the principle of random allocation, 70% of these patients were used as the training set, and 30% as the validation set. Relevant predictive variables were extracted from three aspects: demographic characteristics and basic vital signs, serum indicators within 24 hours of intensive care unit (ICU) admission and complications possibly affecting indicators, functional scoring and advanced life support. The predictive efficacy of models constructed using five mainstream machine learning algorithms including decision tree classification and regression tree (CART), random forest (RF), support vector machine (SVM), linear regression (LR), and super learner [SL; combined CART, RF and extreme gradient boosting (XGBoost)] for 28-day death in patients with septic shock was compared, and the best algorithm model was selected. The optimal predictive variables were determined by intersecting the results from LASSO regression, RF, and XGBoost algorithms, and a predictive model was constructed. The predictive efficacy of the model was validated by drawing receiver operator characteristic curve (ROC curve), the accuracy of the model was assessed using calibration curves, and the practicality of the model was verified through decision curve analysis (DCA).Results:A total of 3?295 patients with septic shock were included, with 2?164 surviving and 1?131 dying within 28 days, resulting in a mortality of 34.32%. Of these, 2?307 were in the training set (with 792 deaths within 28 days, a mortality of 34.33%), and 988 in the validation set (with 339 deaths within 28 days, a mortality of 34.31%). Five machine learning models were established based on the training set data. After including variables at three aspects, the area under the ROC curve (AUC) of RF, SVM, and LR machine learning algorithm models for predicting 28-day death in septic shock patients in the validation set was 0.823 [95% confidence interval (95% CI) was 0.795-0.849], 0.823 (95% CI was 0.796-0.849), and 0.810 (95% CI was 0.782-0.838), respectively, which were higher than that of the CART algorithm model (AUC = 0.750, 95% CI was 0.717-0.782) and SL algorithm model (AUC = 0.756, 95% CI was 0.724-0.789). Thus above three algorithm models were determined to be the best algorithm models. After integrating variables from three aspects, 16 optimal predictive variables were identified through intersection by LASSO regression, RF, and XGBoost algorithms, including the highest pH value, the highest albumin (Alb), the highest body temperature, the lowest lactic acid (Lac), the highest Lac, the highest serum creatinine (SCr), the highest Ca 2+, the lowest hemoglobin (Hb), the lowest white blood cell count (WBC), age, simplified acute physiology score Ⅲ (SAPSⅢ), the highest WBC, acute physiology score Ⅲ (APSⅢ), the lowest Na +, body mass index (BMI), and the shortest activated partial thromboplastin time (APTT) within 24 hours of ICU admission. ROC curve analysis showed that the Logistic regression model constructed with above 16 optimal predictive variables was the best predictive model, with an AUC of 0.806 (95% CI was 0.778-0.835) in the validation set. The calibration curve and DCA curve showed that this model had high accuracy and the highest net benefit could reach 0.3, which was significantly outperforming traditional models based on single functional score [APSⅢ score, SAPSⅢ score, and sequential organ failure assessment (SOFA) score] with AUC (95% CI) of 0.746 (0.715-0.778), 0.765 (0.734-0.796), and 0.625 (0.589-0.661), respectively. Conclusions:The Logistic regression model, constructed using 16 optimal predictive variables including pH value, Alb, body temperature, Lac, SCr, Ca 2+, Hb, WBC, SAPSⅢ score, APSⅢ score, Na +, BMI, and APTT, is identified as the best predictive model for the 28-day death risk in patients with septic shock. Its performance is stable, with high discriminative ability and accuracy.

At present, total hip arthroplasty (THA) is the primary treatment for hip diseases such as femoral head necrosis and developmental dysplasia of the hip. It has good effects in reducing pain and improving joint function. The appearance of modular hip prosthesis facilitates adjustment of limb length and femoral offset. However, the wear between the interface of hip prosthesis can lead to inflammatory pseudotumor, osteolysis and other adverse reactions. To explore the risk factors of wear between hip prosthesis interface is helpful to improve the design and manufacturing concept of the product, improve the product performance, help surgeons optimize the operation technology and reduce the impact of human factors on the wear of the prosthesis. Many literatures have reported the mechanism of wear between the head-acetabula interface of prosthesis. The mechanism of wear between the interfaces has been described relatively clearly. In addition to the head-acetabula interface, the wear between the head-neck interface is another major cause of unexplained pain around the joint and prosthesis loosening after hip replacement. Many factors affect head-neck wear. The design of prosthesis (such as prosthesis material and prosthesis taper), surgical technology (such as impact strength and prosthesis mismatch) and patient factors (such as age, gender and activity) have important impact on head-neck wear. Adverse reactions caused by head-neck wear have also been widely concerned. However, there is no considerable solution for wear prevention. Thus, we should optimize the design of prosthesis, improve the surgical technology, and guide the rehabilitation of patients to prevent wear. In order to improve the attention of joint surgeons, the present paper reviews the literatures and analyzes the risk factors of head-neck interface wear and the clinical manifestations caused by head-neck wear.

Objective To evaluate the effect of ditching for drain on the control of the breed of Oncomelania hupensis snails in beaches of Dongting Lake. Methods From November,2009 to November,2012,an O. hupensis snail infested beach of the Yueyang jail and an O. hupensis snail infested beach of Junshan District were selected as research fields in the eastern Dongting Lake area,and the former,as the intervention field,was performed with the ditching for drain by excavators and the latter,as the control field,was not. Results Before the project implemented,the average soil moisture contents on the beaches in dry seasons of the two fields were both about 35.56%. After the project implemented,in the intervention field,the average soil mois?ture content was 26.53%which was significantly lower than that(35.56%)in the control field(F=6.53,P<0.05). The under?ground water levels in different heights in the intervention field were lower than those in the control field (χ2 = 33.33,P <0.05). Before the project implemented,the natural death rates of the snails were 0.98%and 0.89%in the two research fields re?spectively(P>0.05),and after the project implemented(in 2012),no adult and young snails were found in the interventional field,but in the control field,the average densities of living snails and young snails were 29.37 snails/0.1 m2 and 213±108.45 snails/0.1 m2 respectively. Conclusion The intervention of ditching for drain can decrease the soil moisture contents quickly and change the ecological condition,therefore,can control the breed of O. hupensis snails in the beaches of Dongting Lake.

BACKGROUND:Electrospinning preparation for the tissue engineering scaffold materials is an extremely promising technology.
OBJECTIVE:To review the progress of electrospinning technology in different fields and its main problems in the current application.
METHODS:We searched Medline and CNKI databases for articles published from 2000 to 2013 using the keywords of“electrospinning, tissue engineering”in English and Chinese.
RESULTS AND CONCLUSION:The structure of non-woven cloth materials made by this technology is similar to the extracel ular matrix, which has high surface area and control able mechanical properties. Electrospinning materials have been widely applied in the tissue engineering field, especial y in the biodegradable materials and high biocompatibility molecular polymer synthesis process. Electrospinning has been developed rapidly in tissue engineering applications, especial y in the choice of materials or electrospinning technique combined with different technologies. Different morphological structures and properties of the materials can be wel combined by using electrospinning technology. A series of new polymers were successful y incorporated into a tissue engineering scaffold as the matrix for cel proliferation and regeneration, but there are some important issues to be solved, including how to control the interaction between the scaffold and the biological system that is to achieve the infiltrative growth of cel s, how to control the pore size, mechanical properties and toxicity. This technology clinical y applied in biomedicine stil requires further research, especial y in vivo studies.

Objective To investigate the short-term surgical effect and complications of posterior dislocation of the hip with femoral head fractures.Methods Twenty-two patients with posterior dislocation of the hip with femoral head fractures treated surgically from December 1999 to December 2008 were reviewed retrospectively.All the patients were males aged from 23-52 years (mean 39.2 years).According to Pipkin classification,fractures were type Ⅰ in nine cases (41％),type Ⅱ in seven (32％),type Ⅲ in two (9％) and type Ⅳ in four (18％).Different surgical approaches and treatment methods were employed together with a periodic follow-up.Harris score and Thompson & Epstein score were used as measurement standard in postoperative clinical and radiological follow-up.Postoperative complications were analyzed as well.Results All the patients were followed up for mean 36 months.Clinical outcome as assessed by Harris criteria was excellent in 10 cases,good in seven,fair in two and poor in three,with excellent-good rate of 77％.Complications included femoral head avascular necrosis in four cases and traumatic arthritis in six.Heterotopic ossification of the hip did not occur.One case complicated with idiopathic injury of sciatic nerve was recovered at one year after operation.Conclusions Posterior dislocation of the hip with femoral head fractures should be operated as soon as possible.Operational modalities should depend on the type of fractures for the sake of reducing complications.

BACKGROUND:Magnesium al oy as a fracture fixation material has mechanical properties similar to the bone, good biocompatibility and biodegradability, but its rapid degradation rate in body fluids becomes a clinical bottleneck. Therefore, the use of surface treatments to improve its corrosion resistance is important.
OBJECTIVE:To use magnetron sputtering technology and alkali heat treatment technology in the preparation of coating characterized as both corrosion resistance and biological activity.
METHODS:First, we prepared Mg-Zn-Mn al oy using the smelting technology, and prepared a dense coating on the al oy surface by the magnetron sputtering technique. Then, we processed the coating surface using an alkaline solution, and studied the corrosion behavior of the coating by use of simulated body fluid experiments. We speculated the biological activity of the coating by measuring the content of calcium and phosphorus from the surface products.
RESULTS AND CONCLUSION:We prepared the coating, which had both corrosion resistance and biological activity, on the surface of magnesium al oy by use of magnetron sputtering and alkali heat treatment technology. After soaking in the simulated body fluid for 24 hours and 168 hours, the deposition of the coating surface contained Ca, P products. Ca/P ratios were 1.54 and 2.11, respectively, closed to the bone-phosphate Ca/P ratio. The coating surface formed 5-10μm pitting after 24 hours of immersion, and the pitting grew up with the immersion time. The pitting was enlarged to 100-800μm after 168 hours.

ObjectiveTo investigate the relationship between the expression of ER,PR,HER-2,Ki-67 and the effective rate of neoadjuvant chemotherapy (NAC) and to study the influence of NAC on expression of ER,PR,HER-2 and Ki-67 in breast cancer.Methods41 patients of breast cancer were performed 2 to 6 cycles of CAF chemotherapy.The expression of ER,PR,HER-2 and Ki-67 was detected by SP immunohistochemical method before and after NAC.ResultsThe effective rate of NAC was 73.17％ (30/41).The positive and negative efficiency rate was 67.86％ (19/28) vs 84.62％ ( 11/13 ) for ER,64.29％ (9/14) vs 77.78％ (21/27 ) for HER-2,70.00％ (14/20) vs 76.19％ ( 16/21 ) for Ki-67.The difference had no statistical significance (P ＞0.05).The positive and negative efficiency rate was 66.67％ (16/24) vs 82.35％ (14/17) for PR.The difference had statistical significance (P ＜ 0.05 ).The expression of ER,PR,HER-2 and Ki-67 before and after NAC changed in 10,8,3 and 9 cases respectively.The difference had no statistical significance (P ＞ 0.05).ConclusionsNAC has no influence on the expression of ER,PR,HER-2 and Ki-67.Patients with PR negative are more sensitive to NAC.The expression state of PR can be used to predict the curative effect of NAC.The expression state of ER,HER-2 and Ki-67 has no significant correlation with NAC.

BACKGROUND: Bone metabolism disorder happens in diabetic environment, bone defects in which are difficult to repair. Study addressing osteogenic property of adipose-derived stroma cells (ADSCs) in diabetic environment provides theoretical basis for its application in certain environment.OBJECTIVE: To explore the effects of high glucose (HG) and advanced glycation end-products (AGEs) on osteogenic capacity of human ADSCs. METHODS: 100 mg/L AGEs and 27.5 mmol/L HG were used to simulate in vitro diabetic environment and intervened ADSCs osteogenic differentiation. The cells were divided into 4 groups, with 6 samples in each group. The expression of type Ⅰ collagen was examined by fluorescent immunofluorescence at 21 days after osteogenic induction. The number of calcification nodes was counted under contrast phase microscopy at 14, 21 and 28 days. RESULTS AND CONCLUSION: Fluorescent quantitation scan showed that the type Ⅰ collagen amount of the AGEs+HG treated group was 2.76 times lower than that of the control group. AGEs+HG reduced the number of ADSCs calcification nodes compared with the control, HG, and AGEs groups, the differences were statistical significant (P < 0.01). AGEs and HG exposure inhibit the cognate osteogenic differentiation of ADSCs, which suggest that AGEs and HG are unfavorable factors that reduce ADSCs osteogenic ability.

BACKGROUND: Adult acetabular dysplasia in advanced stage combined with hip joint osteoarthritis should undergo total hip replacement. The severity of acetabular lesion is various in different patients, which leads to significantly increased difficulty in reestablishing acetabulum. Acetabular medial wall displacement osteotomy can solve the component of acetabular prosthesis, but the displacement range of the acetabular medial wall following osteotomy is controversial.OBJECTIVE: To look for a suitable displacement range of acetabular medial wall following osteotomy by computer-aided design finite element analysis.METHODS: SolidWorks 2008 software was used to establish three-dimensional models of acetabular dysplasia pelvis. Acetabular medial wall displacement osteotomy was simulated to make acetabular medial wall bone displace from 2 mm bone contact to 7 mm bone contact in the pelvic cavity. One experimental group was set at 1 mm intervals, totally 10 experimental groups. The acetabulum in each group was split into four quadrants. The prosthesis acetabulum-bone interface in each group was analyzed by computer simulation contrast mechanics experiment. The Mises stress and shear stress values were measured between acetabular prosthesis and bone interface.RESULTS AND CONCLUSION: In groups 1, 5, 6, 9 and 10, the Mises stress was unevenly distributed in posterior inferior, anterior superior and anterior inferior quadrants. In groups 2, 3, 4, 7 and 8, the Mises stress was evenly distributed in posterior inferior,anterior superior and anterior inferior quadrants. Of them, the stress was most even in the group 4. In groups 2, 3, 4, 7 and 8, the shear stress was evenly distributed in the above-mentioned three quadrants. The shear stress was lowest in the groups 7 and 8.These indicate that joint force in the acetabulum mainly focused in the posterior superior quadrant. With the displacement of acetabular cup, the contact area of acetabular cup and bone would gradually increase, which finally increased the Mises stress in the contact surface. However, shear stress decreased with displacement of acetabular medial wall. Therefore, the suitable displacement range of acetabular medial wall osteotomy is 1 mm away from the pelvic cavity and 1 mm complete embolism in the pelvic cavity. The optimal position was 1 mm complete embolism in the pelvic cavity.

BACKGROUND: During the hip replacement, selection of prosthesis often depends on patients' bone condition. There has been no gold standard for selection of prosthesis. It will be of scientific significance to select femoral prostheses implanted under different bone densities through three-dimensional finite element analysis and simulated contrast mechanical tests.OBJECTIVE: Three-dimensional finite element analysis was employed to select femoral prostheses according to different bone densities, and simultaneously simulated contrast mechanical tests were performed to determine the age criteria regarding the selection of femoral prosthesis during the hip replacement.DESIGN, TIME AND SETTING: An open experiment was performed at the Second Department of Orthopedics, First Clinical Hospital of Jilin University and Institute of Biomechanics, Jilin University between September 2006 and May 2007.MATERIALS: Freshly adult femoral specimens were harvested from cadavers.METHODS: Three-dimensional finite element models of femur were established using Solidworks software. Following the known formula, the bone density and elastic modulus at different age brackets were calculated and input into the computer. The human one-foot standing condition was simulated and pressure was loaded on the reconstructed femoral models.MAIN OUTCOME MEASURES: Some biomechanical characteristics of uncemented and cemented femoral prostheses, such as the distress distribution and initial micromovement at different bone densities, were measured.RESULTS: Relatively well-distributed whole distress and slight initial micromovement of uncemented femoral prostheses were found in male patients at 30-60 years old and in female patients at 40-55 years old. Symptoms of cemented femoral prostheses the same as the uncemented femoral prostheses were present in male patients at 60-70 years and in female patients older than 55 years old.CONCLUSION: Results of three-dimensional finite element analysis and simulated contrast mechanical tests suggest that uncemented femoral prostheses provide better therapeutic effects in male patients younger than 60 years and in female patients younger than 55 years than cemented femoral prosthesis.