Micro-kinetic modelling of the CO reduction reaction on single atom catalysts accelerated by machine learning.

Electrochemical CO2 transformation to fuels and chemicals is an effective strategy for conversion of renewable electric energy into storable chemical energy in combination with reducing green-house gas emission. Metal-nitrogen-carbon (M-N-C) single atom catalysts (SAC) have shown great potential in the electrochemical CO2 reduction reaction (CO2RR). However, exploring advanced SACs with simultaneously high catalytic activity and high product selectivity remains a great challenge. In this study, density functional theory (DFT) calculations are combined with machine learning (ML) for rapid and high-throughput screening of high performance CO reduction catalysts. Firstly, the electrochemical properties of 99 M-N-C SACs were calculated by DFT and used as a database. By using different machine learning models with simple features, the investigated SACs were expanded from 99 to 297. Through several effective indicators of catalyst stability, inhibition of the hydrogen evolution reaction, and CO adsorption strength, 33 SACs were finally selected. The catalytic activity and selectivity of the remaining 33 SACs were explored by micro-kinetic simulation based on Marcus theory. Among all the studied SACs, Mn-NC2, Pt-NC2, and Au-NC2 deliver the best catalytic performance and can be used as potential catalysts for CO2/CO conversion to hydrocarbons with high energy density. This effective screening method using a machine learning algorithm can promote the exploration of CO2RR catalysts and significantly reduce the simulation cost.

Chiral nanocrystals grown from MoS2 nanosheets enable photothermally modulated enantioselective release of antimicrobial drugs.

The transfer of the concept of chirality from molecules to synthesized nanomaterials has attracted attention amongst multidisciplinary teams. Here we demonstrate heterogeneous nucleation and anisotropic accumulation of Au nanoparticles on multilayer MoS2 planes to form chiroptically functional nanomaterials. Thiol amino acids with chiral conformations modulate asymmetric growth of gold nanoarchitectures on seeds of highly faceted Au/MoS2 heterostructures. Consequently, dendritic plasmonic nanocrystals with partial chiral morphologies are synthesized. The chirality of dendritic nanocrystals inherited from cysteine molecules refers to the structural characteristics and includes specific recognition of enantiomeric molecules. With integration of the intrinsic photothermal properties and inherited enantioselective characteristics, dendritic Au/MoS2 heterostructures exhibit chirality-dependent release of antimicrobial drugs from hydrogel substrates when activated by exogenous infrared irradiation. A three-in-one strategy involving synthesis of chiral dendritic heterostructures, enantioselective recognition, and controlled drug release system is presented, which improves nanomaterial synthetic technology and enhances our understanding of crucial chirality information.

[Application of modular cementless femoral stems in complex revision hip arthroplasty].

OBJECTIVE: To investigate and clarify the key surgical techniques and evaluate clinical effectiveness of modular cementless femoral stems(LINK MP modular stem) in complex revision hip arthroplasty. METHODS: From January 2002 to December 2013, 470 patients in Chinese PLA General Hospital received revision hip arthroplasties using MP stems. Among them, 246 patients were followed for an average of 5.7 years (ranged, 0.5 to 11 years). There were 148 males and 98 females, with an average age of 62.5 years old (ranged from 26 to 83 years old). The most common reason for revision was aseptic loosening of femoral stems (107 cases, 43.5%), followed by prosthetic joint infection (104 cases, 42.3%). Other reasons included unexplained hip or thigh pain, periprosthetic femoral fracture, prosthesis wear and dislocation. According to Paprosky classification of femoral deficiency, there were 171 cases of type IIIA (69.5%), 14 cases of type I, 39 cases of type II, and 22 cases of type IIIB. The average preoperative Harris hip score (HHS) was 37.4 ± 7.5. In addition, radiographic presentation, degree of patients' subjective satisfaction, and clinical effectiveness were assessed as well. RESULTS: The average Harris score was im- proved to 87.8 ± 4.2 after operation,with significant statistical difference when compared to preoperative score (t = 92.13,P = 0.00). Analysis of patients' subjective satisfaction for leg length discrepancy, stability and overall degree of satisfaction showed that the number of patients with great satisfaction were 27, 60, 61 respectively. The most common complication was the periprosthetic fracture (intraoperatively 21 cases and postoperatively 8 cases). Other complications included infection (7 cases), dislocation (5 cases), numbness possibly caused by incomplete sciatic nerve injury (6 cases) and thigh swelling (3 cases). The X-ray taken at the final follow-up revealed that prosthesis subsidence occurred in 4 cases, 2 of which needed a second revision. CONCLUSION: The application of modular cementless femoral stems (LINK MP modular stem) in complex revision hip arthroplasty (especially in cases with the serious defect of proximal femoral bone) shows good results at both the short-term and long-term follow-up, especially in the revision for prosthetic infection with the high success rate. In order to avoid complications and improve clinical outcomes,the surgeons should carefully select proper surgery candidates,perform the procedure with care, and master the key surgical techniques.

No evidence of superiority in reducing outliers of component alignment for patient-specific instrumentation for total knee arthroplasty: a systematic review.

Patient-specific instrumentation (PSI) technology has been developed to improve alignment when implanting total knee arthroplasty (TKA) and is a new focus in the orthopaedic community. Current controversial data concerning PSI are discussed. A systematic review to compare PSI with conventional instrumentation and assess the radiographic outcomes was performed. Electronic databases (including PubMed, Medline, Embase, the Cochrane Library and the Science Citation Index database) and conference proceedings from 1950 to 2014 in the English language were searched. Data, including relevant patient characteristics, sample size, radiographic method, PSI system manufacturer and outliers of implant positioning and alignment on radiography were independently extracted from all eligible studies by two of the authors. A total of 2739 TKAs were included (1410 performed with PSI and 1329 with conventional instrumentation). There were more TCA outliers (malalignment >3°) and tibial slope outliers (malalignment >3°) in the PSI group than in the conventional group. The other radiographic outcomes assessed, including coronal, sagittal or rotational alignment outliers did not differ between the two groups. With regard to radiographic outcomes, our findings indicate that PSI technology is not superior in reducing outliers of component alignment.

Over-expression of mitochondrial antiviral signaling protein inhibits coxsackievirus B3 infection by enhancing type-I interferons production.

BACKGROUND: Recent studies have revealed that Mitochondrial Antiviral Signaling (MAVS) protein plays an essential role in the inhibition of viral infection through type I interferon (IFN) pathway. It has been shown that 3C (pro) cysteine protease of coxsackievirus B3 (CVB3) cleaves MAVS to inhibit type I IFNs induction. Other workers also found that MAVS knock-out mice suffered CVB3 susceptibility and severe histopathological change. Accordingly,our experiments were designed to explore the protection of over-expressing MAVS against CVB3 infection and the possible mechanism. RESULTS: In this study, HeLa cells (transfected with MAVS constructs pre- or post- exposure to CVB3) were used to analyze the function of exogenous MAVS on CVB3 infection. The results revealed that though CVB3 infection induced production of type I IFNs, viral replication and cell death were not effectively inhibited. Similarly, exogenous MAVS increased type I IFNs moderately. Morever, we observed robust production of type I IFNs in CVB3 post-infected HeLa cells thereby successfully inhibiting CVB3 infection, as well formation of cytopathic effect (CPE) and cell death. Finally, introduction of exogenous MAVS into CVB3 pre-infected cells also restricted viral infection efficiently by greatly up-regulating IFNs. CONCLUSIONS: In summary, exogenous MAVS effectively prevents and controls CVB3 infection by modulating and promoting the production of type I IFNs. The IFNs level in MAVS over-expressing cells is still tightly regulated by CVB3 infection. Thus, the factors that up-regulate MAVS might be an alternative prescription in CVB3-related syndromes by enhancing IFNs production.