Organic-Inorganic Hybrid Perovskite Ferroelectric Nanosheets Synthesized by a Room-Temperature Antisolvent Method.

Over the past years, the application potential of ferroelectric nanomaterials with unique physical properties for modern electronics is highlighted to a large extent. However, it is relatively challenging to fabricate inorganic ferroelectric nanomaterials, which is a process depending on a vacuum atmosphere at high temperatures. As significant complements to inorganic ferroelectric nanomaterials, the nanomaterials of molecular ferroelectrics are rarely reported. Here a low-cost room-temperature antisolvent method is used to synthesize free-standing 2D organic-inorganic hybrid perovskite (OIHP) ferroelectric nanosheets (NSs), that is, (CHA)2PbBr4 NSs (CHA = cyclohexylammonium), with an average lateral size of 357.59 nm and a thickness ranging from 10 to 70 nm. This method shows high repeatability and produces NSs with excellent crystallinity. Moreover, ferroelectric domains in single NSs can be clearly visualized and manipulated using piezoresponse force microscopy (PFM). The domain switching and PFM-switching spectroscopy indicate the robust in-plane ferroelectricity of the NSs. This work not only introduces a feasible, low-cost, and scalable method for preparing molecular ferroelectric NSs but also promotes the research on molecular ferroelectric nanomaterials.

Voltage-Mode Ferroelectric Synapse for Neuromorphic Computing.

Ferroelectric materials with a modulable polarization extent hold promise for exploring voltage-driven neuromorphic hardware, in which direct current flow can be minimized. Utilizing a single active layer of an insulating ferroelectric polymer, we developed a voltage-mode ferroelectric synapse that can continuously and reversibly update its states. The device states are straightforwardly manifested in the form of variable output voltage, enabling large-scale direct cascading of multiple ferroelectric synapses to build a deep physical neural network. Such a neural network based on potential superposition rather than current flow is analogous to the biological counterpart driven by action potentials in the brain. A high accuracy of over 97% for the simulation of handwritten digit recognition is achieved using the voltage-mode neural network. The controlled ferroelectric polarization, revealed by piezoresponse force microscopy, turns out to be responsible for the synaptic weight updates in the ferroelectric synapses. The present work demonstrates an alternative strategy for the design and construction of emerging artificial neural networks.

Prevalence of incidental thyroid abnormalities in patients with degenerative cervical spondylosis: a retrospective cross-sectional magnetic resonance imaging study.

Background: Incidental thyroid abnormalities found on magnetic resonance imaging (MRI) of the neck are not uncommon. This study aimed to investigate the prevalence of incidental thyroid abnormalities in the cervical spine MRI of the degenerative cervical spondylosis (DCS) population indicated for surgery and to identify patients who require additional workup based on the recommendations of the American College of Radiology (ACR). Methods: All consecutive patients with DCS and indications for cervical spine surgery from October 2014 to May 2019 in the Affiliated Hospital of Xuzhou Medical University were reviewed. All MRI scans of the cervical spine routinely include the thyroid. Cervical spine MRI scans were retrospectively evaluated for the prevalence, size, morphologic characteristics, and location of incidental thyroid abnormalities. Results: A total of 1,313 patients were included in the analysis, 98 (7.5%) of whom were found to have incidental thyroid abnormalities. The most frequent thyroid abnormality was thyroid nodules (5.3%), followed by goiters (1.4%). Other thyroid abnormalities included Hashimoto thyroiditis (0.4%) and thyroid cancer (0.5%). There was a statistically significant difference in age and sex between patients with DCS with and without incidental thyroid abnormalities (P=0.018 and P=0.007). Stratified by age, the results showed that the highest incidence of incidental thyroid abnormalities was found in patients aged 71 to 80 years (12.4%). Eighteen patients (1.4%) needed further ultrasound (US) and relevant workups. Conclusions: Incidental thyroid abnormalities are common in cervical MRI, with a prevalence of 7.5% identified in patients with DCS. Incidental thyroid abnormalities are large or have suspicious imaging features, and further evaluation with a dedicated thyroid US examination should be completed before cervical spine surgery is undertaken.

Gender Differences do not Influence the Blood Coagulopathy in Patients Undergoing Total Knee Arthroplasty: A Retrospective Thromboelastography Analysis.

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). There were significant differences in reaction time (R) and α angle 1 day after the surgery between the two groups (P < .05), but there were no significant differences in other TEG indexes at any corresponding time point 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.

[Study on the application of a new type of vertebral plate nail guide].

OBJECTIVE: To explore safety and accuracy of novel C2 laminar staple guide through in vitro experiments. METHODS: From January 2018 to June 2018, 40 patients who underwent three-dimensional CT of cervical spine were selected, including 21 males and 19 females, heighted from 165 to 180 cm with an average of (172.9±9.5) cm, aged from 38 to 55 years old (51.1±12.8) years old, excluding patients with axis lamina defect and hypoplasia. Two sets of 3D printed specimens were made from the three-dimensional CT data of cervical spine of each patient, and both of than were used for the in vitro nailing experiment. According to different nail placement methods, in vitro experimental part of this experiment was divided into guide nail placement group and hand nail placement group, 40 pieces in each group. At the same time, the three-dimensionalmodel of cervical spine of 40 patients was reconstructed on computer, and the ideal needle point data and inclination angle were obtained by computer simulation of the nail placement. This is 3D simulation nail placement group, 40 pieces. With vitro experiment, the risk level of screw placement, the position of needle exit point and inclination angle were measured in guide nail group and hand nail group. Based on the accuracy of needle point and inclination angle of nail path, the data of guide nail group, the hand nail group and 3D simulation nail group were compared, and the data of each group were statistically analyzed to determine the accuracy. RESULTS: In guide nail group, 75 screws were acceptable and 5 were dangerous. The acceptable rate was 94%, and the double cortical rate was 93%. There were 62 position-acceptable screws in hand nail group, and 18 positions were dangerous, with an acceptable rate of 78% and a double cortical rate of 33%. The difference between two groups was statistically significant (P<0.05). There was no significant difference in accuracy of needle exit point and inclination angle of nail path between guide nail group and 3D simulation nail group (P>0.05), but there was significant difference in the accuracy of needle exit point and inclination angle of nail path between hand nail group and 3D simulation nail group (P<0.05). CONCLUSION: The guide is universal, with stable structure, accurate guidance, and easy operation. It could be placed with bilateral lamina screws at the same time, shortening the time of nail placement, avoiding collision of two way cross screws, increase the rate of double cortex. Ultimately, efficiency and security can be improved.

Application of thromboelastography in comparing coagulation difference of rivaroxaban and enoxaparin for thromboprophylaxis after total hip arthroplasty.

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.

Tourniquet use in primary total knee arthroplasty is associated with a hypercoagulable status: a prospective thromboelastography trial.

STUDY DESIGN: Prospective study. PURPOSE: 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. METHODS: 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. RESULTS: 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). CONCLUSION: 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.

Does subcutaneous administration of recombinant human erythropoietin increase thrombotic events in total hip arthroplasty? A prospective thrombelastography analysis.

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.

Intravenous administration of tranexamic acid in total hip arthroplasty does not change the blood coagulopathy: a prospective thrombelastography analysis.

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.

Engineering cell wall synthesis mechanism for enhanced PHB accumulation in E. coli.

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 prospective randomised comparison of 2 skin closure techniques in primary total hip arthroplasty surgery.

INTRODUCTION: As an essential step of total hip arthroplasty (THA), an effective and secure skin closure technique after primary THA is important. Metallic staples closure and subcuticular suture are the 2 common techniques for skin closure. However, which closure technique is the optimal skin-closure method remains unclear. The purpose of this prospective randomised clinical study was to compare the clinical outcomes and costs between staples and subcuticular suture techniques. METHODS: In this clinical study, 165 patients who underwent primary unilateral THA through a posterolateral approach from August 2014 to May 2015 were included. According to skin closure technique, the patients were randomised into staples group (interrupted suture with staples, 83 cases) and sutures group (running 4-0 absorbable subcuticular suture, 82 cases). The same operative and perioperative care were provided to all patients. The surgical site infections (SSIs) rate, closure time, time to dry wounds and postoperative hospital stay were recorded and compared. Besides, cosmetic results and patient's satisfaction were evaluated with Hollander wound evaluation score (HWES) and VAS score at postoperative 3 months follow-up respectively. Relative total costs were recorded as well. RESULTS: It was shown that no infections developed in sutures group, while 2 postoperative superficial infections (2.4%) occurred in the staples group. There was a statistically significant difference in the time to dry surgical incisions and postoperative hospital stay favoring sutures (4.8 vs. 5.0 days, p = 0.028; 6.0 vs. 12.0 days, p<0.001, respectively). The cutaneous incision closure using staples consumed significantly less time than that with subcuticular suture (24.7 vs. 357.7 seconds, p<0.001). Moreover, there was no significant difference in HWES and patient's satisfaction between the 2 groups. Finally, the application of subcuticular suture saved an average of $82.2 per case. CONCLUSIONS: Closure with running subcuticular suture is cheaper and appears to have a clinical advantage when compared with metallic staples skin closure in primary THA surgery. However, additional operating time may be incurred.

[Effect of admission blood urea and creatinine levels on mortality in elderly patients with hip fracture].

OBJECTIVE: To observe the effect of admission blood urea and creatinine levels on mortality in elderly patients with hip fracture. METHODS: 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, creatinine<70 µmol/L); group C (blood urea<5 mmol/L, creatinine>=70 µmol/L); group D(blood urea<5 mmol/L, creatinine<70 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. RESULTS: 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 [P=0.000, OR=1.375, 95%CI(1.155, 1.637)], blood urea at admission [P=0.000, OR=1.375, 95%CI(1.155, 1.637)], and blood creatinine at admission[P=0.037, OR=1.213, 95%CI(1.121, 1.484)]. CONCLUSIONS: 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.

Effect of Chemical Thromboprophylaxis on the Rate of Venous Thromboembolism After Treatment of Foot and Ankle Fractures.

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.