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Prospective study. The main purpose of this study was to investigate whether the use of a tourniquet changes the blood coagulation state following primary total knee arthroplasty (TKA) by means of conventional coagulation tests and thromboelastography (TEG) analyses. A total of 154 patients who underwent primary unilateral TKA from January 2018 to October 2020 were enrolled. Seventy-nine patients were randomized into a tourniquet group, and 75 were randomized into a no-tourniquet group. Demographic data, surgical time, intra-operative blood loss, transfusion rate, and wound complications were collected. Complete blood count, conventional coagulation tests, and TEG were performed the day before surgery, one day after surgery, three days after surgery, and seven days after surgery. Lower extremity Doppler ultrasound was performed the day before surgery and seven days after surgery. The baseline characteristics of the patients were similar between the two groups. Hidden blood loss, transfusion rate, and wound complications were similar between the two groups, but the intra-operative blood loss of the tourniquet group was lower than that of the no-tourniquet group. The calculated total blood loss of the tourniquet group was higher than that of the no-tourniquet group. In terms of conventional coagulation tests and TEG, the tourniquet group had higher values of fibrin degradation products, D-dimer, maximum amplitude, and coagulation index (p

Purpose: The purpose of this study was to compare the coagulation difference in patients with either rivaroxaban or enoxaparin as thromboprophylaxis after total hip arthroplasty (THA) regarding thromboelastography (TEG) and routine coagulation tests. Patients and methods: Two hundred and twenty-eight patients undergoing primary THA were recruited in this study. They were divided into two groups according to a computer-generated random sequence. Patients in the rivaroxaban group received 10 mg of rivaroxaban orally once daily. Patients in the enoxaparin group received 4000 AxaIU (0.4 mL) of enoxaparin subcutaneously once daily. Rivaroxaban and enoxaparin were started 6–8 h after surgery. The administration of the anticoagulant prophylaxis was lasted for a minimum of 14 days. TEG and routine coagulation tests were performed on the day before the operation and 1 day and 7 days after the operation. Results: No difference was observed in the incidence of deep vein thrombosis (DVT) or pulmonary embolism (PE) between the two groups. There was no significant difference with regard to prothrombin time (PT), activated partial thromboplastin time (PTT), international normalized ratio (INR), and thrombin time (TT) between the two groups. However, while considering TEG, R time of the rivaroxaban group was significantly higher than that of the enoxaparin group ( p = 0.003), whereas the maximum amplitude (MA) ( p = 0.036) value and coagulation index (CI) ( p = 0.002) value were significantly lower than those of the enoxaparin group. Conclusion: With regard to TEG analysis, there was coagulation difference in patients with rivaroxaban and those with enoxaparin as thromboprophylaxis after THA. Under recommended dose of rivaroxaban and enoxaparin, patients undergoing THA were in hypercoagulability on 7days postoperative.

Prospective study.The main purpose of this study was to investigate whether the use of a tourniquet changes the blood coagulation state following primary total knee arthroplasty (TKA) by means of conventional coagulation tests and thromboelastography (TEG) analyses.A total of 154 patients who underwent primary unilateral TKA from January 2018 to October 2020 were enrolled. Seventy-nine patients were randomized into a tourniquet group, and 75 were randomized into a no-tourniquet group. Demographic data, surgical time, intra-operative blood loss, transfusion rate, and wound complications were collected. Complete blood count, conventional coagulation tests, and TEG were performed the day before surgery, one day after surgery, three days after surgery, and seven days after surgery. Lower extremity Doppler ultrasound was performed the day before surgery and seven days after surgery.The baseline characteristics of the patients were similar between the two groups. Hidden blood loss, transfusion rate, and wound complications were similar between the two groups, but the intra-operative blood loss of the tourniquet group was lower than that of the no-tourniquet group. The calculated total blood loss of the tourniquet group was higher than that of the no-tourniquet group. In terms of conventional coagulation tests and TEG, the tourniquet group had higher values of fibrin degradation products, D-dimer, maximum amplitude, and coagulation index (p 0.001). The incidence of deep vein thrombosis (DVT) in the tourniquet group was higher than that in the no-tourniquet group (21.5% compared with 8%; p = 0.019).The application of a tourniquet during TKA significantly increases the amount of calculated total blood loss and does not decrease the post-operative transfusion rate. Using a tourniquet in routine TKA exacerbates the early post-operative hypercoagulable status together with a higher incidence of below-knee asymptomatic DVT observed via conventional coagulation tests, TEG, and ultrasonic Doppler.

Background Anemia is one of severe complications in the perioperative period of total hip arthroplasty (THA). Erythropoietin (EPO) has been considered to improve patients’ anemia state, but its efficiency and safety remains controversial. Methods A total of 152 patients who underwent total hip arthroplasty from January 2017 to March 2019 were randomized to 2 groups. Recombinant human erythropoietin (rHu-EPO) group was treated with rHu-EPO subcutaneous injection 10000 IU after operation and once daily in the next week, while control group was treated with none extra treatment. Routine hematologic examination and thrombelastography (TEG) performed at different time point respectively. Doppler ultrasound for bilateral lower limbs was performed 1 day before surgery and 7 days after surgery. Auxiliary examination outcomes, blood transfusions outcomes, and postoperative complications were recorded as assessment indicators. Results The difference in the relevant indexes of traditional coagulation and TEG values between two groups were not significantly. No significant difference was observed in the incidence of thromboembolism events and other complications between two groups during postoperative period. The amount of intraoperative blood loss was similar between the two groups. However, the postoperative use and dosage of allogeneic blood in the rHu-EPO group were lower than those in the control group. The hemoglobin and hematocrit level in the rHu-EPO group were higher than that in the control group after surgery. Conclusion Postoperative subcutaneous injection of rHu-EPO can improve hematological anemia-related parameters, reduce the use and dosage of allogeneic blood transfusions (ABTs), and has no significant influence on the formation of thrombosis and other complications in patients undergoing total hip arthroplasty in short term.

Objective: Despite the wide use of tranexamic acid (TXA) in the perioperative period of total hip arthroplasty (THA), whether the hemostatic state changes after the application of intravenous (IV)-TXA are still unknown. The aim of this study was to investigate whether IV administration of TXA changes the blood coagulation following primary THA via thrombelastography (TEG) analysis and conventional laboratory tests. Methods: A total of 174 patients who underwent primary THA from September 2016 to July 2018 were selected. They were randomly divided into two groups, 86 patients with IV administration of 15 mg/kg TXA and 88 controls without TXA usage. Demographic data, TEG paremeters, d-dimer levels, fibrin degradation products, hemoglobin, hematocrit concentration, platelet, transfusion rates, perioperative blood loss, and the occurrence of deep vein thrombosis were collected. TEG and conventional laboratory tests were performed the day before operation, the first day after operation, and seventh day after operation. Results: There were no differences with regard to TEG or conventional laboratory tests between the two groups ( p > 0.05). The total blood loss and drain blood loss in the TXA group were significantly lower than those in the control group ( p < 0.05). The transfusion rates and the volume of blood transfusion of the control group were higher than those of the TXA group ( p < 0.05). Conclusion: The administration of IV-TXA resulted in a significant reduction in total blood loss, transfusion volumes, and transfusion rates without the increase of thromboembolic complications. Moreover, it was confirmed that TXA would not change the coagulation via the TEG analysis.

Objective :To explore the safety and accuracy of the novel C2 laminar staple guide through in vitro experiments. Methods 40 cases of cervical spine 3D CT data were selected to produce the same two sets of 3D printed specimens (groups a and b), and the self-made guide was used to assist nail placement on group a specimens (group A: guide nail placement group), and group b Laminate nails were placed free-hand on the specimens (group B: free-hand nailing group), and a three-dimensional modeled simulated nailing was reconstructed on the computer (group C: 3D simulated nailing group). Simultaneously measure the danger level, the position of the needle exit point and the inclination angle of the screw placement position of each group. Results :In group A, 75 screws were acceptable and 5 were dangerous. The acceptable rate was 93%, and the double cortical rate was 92%. There were 62 position-acceptable screws in group B, and 18 positions were dangerous, with an acceptable rate of 77% and a double cortical rate of 32%. There was a statistically significant difference between the two groups (P Conclusion: The guide is universal, with stable structure, accurate guidance, and easy operation. It can be placed with bilateral lamina screws at the same time, shortening the time of nail placement, avoiding the collision of two-way cross screws, increase the rate of double cortex. Ultimately, efficiency and security can be improved.

The rigidity of bacterial cell walls synthesized by a complicated pathway limit the cell shapes as coccus, bar or ellipse or even fibers. A less rigid bacterium could be beneficial for intracellular accumulation of poly-3-hydroxybutyrate (PHB) as granular inclusion bodies. To understand how cell rigidity affects PHB accumulation, E. coli cell wall synthesis pathway was reinforced and weakened, respectively. Cell rigidity was achieved by thickening the cell walls via insertion of a constitutive gltA (encoding citrate synthase) promoter in front of a series of cell wall synthesis genes on the chromosome of several E. coli derivatives, resulting in 1.32-1.60 folds increase of Young's modulus in mechanical strength for longer E. coli cells over-expressing fission ring FtsZ protein inhibiting gene sulA. Cell rigidity was weakened by down regulating expressions of ten genes in the cell wall synthesis pathway using CRISPRi, leading to elastic cells with more spaces for PHB accumulation. The regulation on cell wall synthesis changes the cell rigidity: E. coli with thickened cell walls accumulated only 25% PHB while cell wall weakened E. coli produced 93% PHB. Manipulation on cell wall synthesis mechanism adds another possibility to morphology engineering of microorganisms.

A large eddy simulation (LES) is performed for two subsonic jets with a Reynolds number of $$Re=10^5$$ , which have different core temperatures, i.e., the cold and hot jet. The far-field overall sound pressure levels (OASPL) and noise spectra are well validated against previous experimental results. It is found that the OASPL is raised by heating at shallow angles. The most energetic coherent structures are extracted with specified frequencies using the filter based on the frequency domain variant of the snapshot method of proper orthogonal decomposition (POD). The $$m=0,1$$ modes have high coherence of near-field pressure for both jets, while the coherence of $$m=0$$ modes is enhanced greatly by heating. Based on the coherent structures, spatial wavepackets are educed and the characteristics of growth, saturation and decay are analyzed and compared between the two jets in detail. The results show that heating would enhance the linear growth rate for high frequency components, and nonlinear growth rates for low frequency components in general, which are responsible for higher OASPL in the hot jet. The far-field sound generated by wavepackets is computed using the Kirchhoff extrapolation, which matches well with that of LES at shallow angles. This indicates that the wavepackets associated with coherent structures are dominant sound sources in forced transitional turbulent jets. Additionally, the present POD method is proven to be a robust tool to extract the salient features of the wavepackets in turbulent flows.

A subsonic transitional jet is simulated by large eddy simulation, while the flow and acoustic properties are validated against existed experimental results. In the hydrodynamic region, the total disturbance kinetic energy declines as azimuthal wavenumber ( m ) or frequency increases. In the far field, the acoustic field is dominated by the axisymmetric and first helical modes, and the peak of sound spectra at small polar angles to the jet axis are found be located in the range of Strouhal number S t = 0.2 − 0.3 . In order to understand the relationship between instability waves and noise generation, the parabolized stability equation (PSE) is solved for describing the evolution of instability waves. For the acoustic field, the linear model and nonlinear interaction model are built based on PSE solutions in combination with Lilley–Goldstein’s analogy. The beam patterns of above two models are in agreement with experimental results qualitatively, while the nonlinear interaction model predicts more accurate directivity and locations of sound sources. Quantitatively, the linear model underestimates the sound pressure level (SPL) greatly. Nonlinear interaction can enhance the strength of sound sources and raise acoustic efficiency at small polar angles. In some cases, the nonlinear interaction of two instability waves can even increase SPL by nearly 20 dB. However, for m ≥ 2 , the nonlinear interaction model fails to predict reasonable results qualitatively.

Objective Deep vein thrombosis (DVT) is one of the severe complications after total knee arthroplasty (TKA). Gender has been considered to influence the incidence of the thrombosis formation in TKA patients. However, it remains controversial which gender would be more prone to form thrombosis. The aim of this study was to assess the effects of gender differences on coagulation status after TKA via the thromboelastography (TEG). Methods A total of 57 male patients who underwent primary TKA from September 2015 to January 2021 were included in this study. According to the matching principle of age, body mass index (BMI), and anticoagulation treatment, 60 female patients were selected. The conventional coagulation tests, routine blood tests, and thromboelastography were conducted before the operation, 1 day and 7 days after the operation. In addition, Doppler ultrasound was also performed 1 day before the operation and at the 7 days after the operation. The parameters of conventional coagulation tests, routine blood tests, and thromboelastography were compared between the two groups. Results There were no significant differences in the blood transfusion rate, the incidence of DVT during the perioperative period, D-dimer (D-D), fibrin degradation products (FDP), hemoglobin (HB), hematocrit (HCT), prothrombin time (PT), activated partial thromboplastin time (APTT), and C-reactive protein (CRP) at any corresponding time point between the male group and the female group ( P > .05). There were no significant differences in neutrophil-to-lymphocyte ratio (NLR) preoperatively; however, there were significant differences in NLR 1 day after the surgery and 7 days after the surgery between the two groups ( P .05). Binary logistic regression analysis demonstrated that gender, age, BMI, tourniquet application time were not independent predictors ( P > .05). Conclusion Gender differences have no significant influence in TKA patients with regard to conventional coagulation tests and thromboelastography.

Dwell time estimation plays an important role in the operation of urban rail system. On this specific problem, a range of models based on either polynomial regression or microsimulation have been proposed. However, the generalization performance of polynomial regression models is limited and the accuracy of existing microsimulation models is unstable. In this paper, a new dwell time estimation model based on extreme learning machine (ELM) is proposed. The underlying factors that may affect urban rail dwell time are analyzed first. Then, the relationships among different factors are extracted and modeled by ELM neural networks, on basis of which an overall estimation model is proposed. At last, a set of observed data from Beijing subway is used to illustrate the proposed method and verify its overall performance.

Large eddy simulation was performed for two jets, i.e. a cold jet and its heated counterpart, with the same exit Mach number. The far-field noise was predicted by Kirchhoff's integral method based on the near-field pressure fields on a controlled surface. The directivity and intensity of the far-field noise are found to be in good agreement with existed experiments. At polar angles < 70°, heating enhances the noise intensity, while the noise intensity for the cold jet at angles > 70° is higher. For the heated jet, the potential core length is shorter, and radial spreading is much faster. Moreover, the peak locations of the fluctuation intensity of the velocity on the centreline and nozzle lip line move upstream in the hot jet, and more rapid decay occurs. Based on the mean flow of simulation, linear parabolized stability equations (LPSE) are solved to study spatial evolution of instability waves. In the low-frequency range, m = 0 mode that absent in direct forcing is dominant in acoustic field, but the peak of N-factor of m = 0 mode predicted by LPSE is not the maximum. This should be associated with nonlinear interaction for instability waves with opposite signs of m.

To observe the effect of admission blood urea and creatinine levels on mortality in elderly patients with hip fracture.Form January 2013 to December 2014, 767 elder patients with hip fracture were treated in our hospital including 253 males and 514 females, aged from 65 to 96 years old with an average of(75.67±6.81) years old. According blood urea and creatinine levels, the 767 hip fracture patients were divided into four groups as follow: group A(blood urea=5 mmol/L, creatinine=70 μmol/L); group B (blood urea=5 mmol/L, creatinine70 μmol/L); group C (blood urea5 mmol/L, creatinine=70 μmol/L); group D(blood urea5 mmol/L, creatinine70 μmol/L). In group A, there were 211 patients including 70 males and 141 females, aged from 65 to 95 years old with an average of(80.24±6.51) years old; in group B, there were 355 patients including 125 males and 230 females, aged from 65 to 93 years old with an average of(78.46±7.09) years old; in group C, there were 36 patients including 11 males and 25 females, aged from 65 to 95 years old with an average of (77.83±6.78) years old; in group D, there were 165 patients including 47 males and 118 females, aged from 65 to 96 years old with an average of (76.71±8.35) years old. The survivals and dead patients in four groups were collected and in-hospital mortality rate, 3-month, 12-month and 18-month mortality rate of patients were calculated. COX regression analysis was performed on these data, and clinical significance of serum urea and creatinine at admission in the elderly patients was researched.All 767 hip fracture patients were followed up from 18 to 24 months with an average of (21.33±1.25) months, 159 patients were died in follow up period. The in-hospital mortality rate in 3-month, 12-month and 18-month mortality rate of the patients with high blood urea and high blood creatinine (urea=5 mmol/L, creatinine=70 μmol/L) were 2.37%, 9.95%, 16.11% and 26.07%, and were higher than other three groups respectively. COX regression analysis revealed that the independent predictors effecting the mortality rate included age [Elderly hip fracture patients with high serum urea and high serum creatinine at admission indicate higher fatality rate. Age, serum urea and serum creatinine at admission were independent predictors of fatality rate of elderly hip fracture patients.

Background: Venous thromboembolism (VTE) is a well-documented complication in patients with lower limb fractures, but management guidelines for its prevention in isolated foot and ankle fracture patients are conflicting. The aim of this study was to conduct a multicenter, prospective cohort study to define the prevalence of VTE in patients with isolated foot and ankle fractures and determine whether routine prophylaxis is necessary in these patients. Methods: In a double-blind, placebo-controlled study, consecutive patients in 3 hospitals who met our criteria were enrolled. After randomization, patients received either thromboprophylaxis with low-molecular-weight heparin units (LMWH group) or placebo (placebo group) for a period of 2 weeks. All patients underwent routine ultrasonography 1 day preoperatively, 1 week postoperatively, and 1 month postoperatively. Demographic parameters were then collected and compared. Results: Of the 814 patients who met our criteria, 19 patients (2.3%, 95% confidence interval [CI], 0%-31.9%) were found to have objectively confirmed VTE, but none of the patients were symptomatic. Of the 411 patients in the LMWH group, 2 developed VTEs preoperatively and 4 postoperatively; of the 403 patients in the placebo group, 5 developed VTEs preoperatively and 8 postoperatively. The overall incidence of asymptomatic postoperative deep vein thrombosis (DVT) was 0.98% (95% CI 0%-20.3%) in the LMWH group and 2.01% (95% CI 0%-29.5%) in the placebo group without significant difference. Advanced age (odds ratio [OR] 1.050, 95% CI 1.014-1.088, P = .007) and high body mass index (OR 1.201, 95% CI 1.034-1.395, P = .016) were identified as risk factors in predicting occurrence of DVT. No fatal pulmonary emboli or major bleeding complication occurred in either group. Conclusion: Routine anticoagulant prophylaxis was not found to be necessary for patients with foot and ankle fractures, although further investigation with a properly powered study design is required to definitively determine which foot and ankle patients are best served by anticoagulation and which ones are not. Level of Evidence: Level II, prospective comparative study.

A direct simulation with selected inflow forcing is performed for an accurate description of the jet flow field and far-field noise. The effects of the Mach number and heating on the acoustic field are studied in detail. The beam patterns and acoustic intensities are both varied as the change of the Mach number and temperature. The decomposition of the source terms of the Lilley–Goldstein (L–G) equation shows that the momentum and thermodynamic components lead to distinctly different beam patterns. Significant cancellation is found between the momentum and thermodynamic components at low polar angles for the isothermal jet and large polar angles for the hot jet. The cancellation leads to the minimum values of the far-field sound. Based on linear parabolized stability equation solutions, the nonlinear interaction model for sound prediction is built in combination with the L–G equation. The dominant beam patterns and their original locations predicted by the nonlinear model are in good agreement with the direct simulation results, and the predictions of sound pressure level (SPL) by the nonlinear model are relatively reasonable.