2D Co metal-organic framework nanosheet as an oxidase-like nanozyme for sensitive biomolecule monitoring

Nanozyme-based biomolecules sensitive and quantitative detection is an attractive strategy due to their high chemical,thermal stability and reactive activity.Here,we have synthesized a significant number of two-dimensional(2D)cobalt-metal-organic framework(Co-MOF)nanosheets with oxidase(OXD)-like activity using a facile solvothermal method in one pot for biomolecule monitoring.

Predictors and reduction techniques for irreducible reverse intertrochanteric fractures

Background:Reverse intertrochanteric fractures are usually initially treated with closed reduction.However,sometimes these fractures are not amenable to closed reduction and require open reduction.To date,few studies have been conducted on predictors of and reduction techniques for irreducible reverse intertrochanteric fractures.Therefore,this study aimed to summarize the displacement patterns of irreducible reverse intertrochanteric fractures and corresponding reduction techniques,and explore predictors of irreducibility.Methods:We reviewed 1174 cases of trochanteric fractures treated in our hospital from January 2006 to October 2018,113 of which were reverse intertrochanteric fractures.An irreducible fracture was determined according to intra-operative fluoroscopy imaging after closed manipulation.Fractures were assessed for displacement patterns,radiographic features of irreducibility,and reduction techniques.Logistic regression analysis was performed on potential predictors for irreducibility,including gender,age,body mass index,AO Foundation/Orthopaedic Trauma Association(AO/OTA)classification,and radiographic features.Results:Seventy-six irreducible fractures were identified,accounting for 67%of reverse intertrochanteric fractures.Six patterns of fracture displacement after closed manipulation were identified;the most common pattern was medial displacement and posterior sagging of the femoral shaft relative to the head-neck fragment.Multivariate logistic regression analysis identified three predictors of irreducibility:a medially displaced femoral shaft relative to the head-neck fragment on the anteroposterior(AP)view(odds ratio[OR],8.00;95%confidence interval[CI],3.04–21.04;P<0.001),a displaced lesser trochanter(OR,3.61;95%CI,1.35–9.61;P=0.010),and a displaced lateral femoral wall(OR,2.92;95%CI,1.02–8.34;P=0.046).Conclusions:A high proportion of reverse intertrochanteric fractures are not amenable to closed reduction.Six patterns of fracture displacement after closed manipulation were identified.Different reduction techniques are required for different displacement patterns.Predictors of irreducibility include a medially displaced femoral shaft relative to the head-neck fragment on the AP view,a displaced lesser trochanter,and a displaced lateral femoral wall.These patients warrant special consideration in terms of recognition and management.

Loss of the posteromedial support:a risk factor for implant failure after fixation of AO 31-A2 intertrochanteric fractures

Background:The purpose of this study was to analyze cases of AO31-A2 intertrochanteric fractures(ITFs)and to identify the relationship between the loss of the posteromedial support and implant failure.Methods:Three hundred ninety-four patients who underwent operative treatment for ITF from January 2003 to December 2017 were enrolled.Focusing on posteromedial support,the A2 ITFs were divided into two groups,namely,those with(Group A,n=153)or without(Group B,n=241)posteromedial support post-operatively,and the failure rates were compared.Based on the final outcomes(failed or not),we allocated all of the patients into two groups:failed(Group C,n=66)and normal(Group D,n=328).We separately analyzed each dataset to identify the factors that exhibited statistically significant differences between the groups.In addition,a logistic regression was conducted to identify whether the loss of posteromedial support of A2 ITFs was an independent risk factor for fixation failure.The basic factors were age,sex,American Society of Anesthesiologists(ASA)score,side of affected limb,fixation method(intramedullary or extramedullary),time from injury to operation,blood loss,operative time and length of stay.Results:The failure rate of group B(58,24.07%)was significantly higher than that of group A(8,5.23%)(χ2=23.814,P<0.001).Regarding Groups C and D,the comparisons of the fixation method(P=0.005),operative time(P=0.001),blood loss(P=0.002)and length of stay(P=0.033)showed that the differences were significant.The logistic regression revealed that the loss of posteromedial support was an independent risk factor for implant failure(OR=5.986,95%CI:2.667-13.432)(P<0.001).Conclusions:For AO31-A2 ITFs,the loss of posteromedial support was an independent risk factor for fixation failure.Therefore,posteromedial wall reconstruction might be necessary for the effective treatment of A2 fractures that lose posteromedial support.

A volume of fluid simulation of the steady deformation and the drag of a single droplet in a flowing gas

A method is proposed to investigate the steady deformation and the drag of a single droplet in a flowing gas at a high Reynolds number.The volume of fluid(VOF)method is used to model the droplet surface structure.The direct numerical simulation(DNS)method is used to model the gas flow field.In order to avoid the effect of the droplet acceleration on the drag and reduce the computation cost,a body force is added to the droplet to make it fixed at a constant position.The body force is determined by using the Newton iteration procedure.The simulated droplet aspect ratio and the drag coefficient agree well with the published experimental data.Meanwhile,the sources of the drag are analyzed and the effect of the Reynolds number and the Weber numbers on the droplet deformation and the drag are studied.The drag mainly comes from the pressure difference between the droplet-leading zone and the trailing zone,and the turbulence wake would increase the drag.