L-Type Ligand-Assisted Acid-Free Synthesis of CsPbBr3 Nanocrystals with Near-Unity Photoluminescence Quantum Yield and High Stability.

X-type ligands, for example, the pair of oleylamine (OAm) and oleic acid (OA), have been widely used to prepare CsPbX3 nanocrystals (NCs). However, the proton exchange between coordinated OAm and OA may induce the detachment of ligands, resulting in poor performance after cleaning or long-time storage. Herein, density functional theory calculations predict that primary amines (L-type ligands) can stabilize a PbBr x-rich surface and yield a trap-free material with fully delocalized valence band maximum and conduction band minimum states, which can significantly improve the photophysical properties and stability of CsPbBr3 NCs. Along this prediction, a room-temperature reprecipitation method using L-type ligands (OAm, n-octylamine, or undecylamine) as the sole capping ligand has been developed to synthesize high-quality CsPbBr3 NCs with near-unity photoluminescence quantum yield and dramatically improved stability against purification and water treatment. The enhancement can be attributed to the strong binding of unprotonated amines to lead atoms and the effective surface passivation provided by the resulted PbBr x-rich surface, which are highly consistent with the theoretical predictions. This work not only offers an approach to synthesize high-quality perovskite NCs but also provides an in-depth understanding of the surface modification of CsPbX3 NCs for practical applications.

Combined approaches for fixation of Schatzker type II tibial plateau fractures involving the posterolateral column: a prospective observational cohort study.

INTRODUCTION: This study aimed to investigate the surgical techniques and the clinical efficacy of combined approaches for the treatment of Schatzker type II tibial plateau fractures involving the posterolateral column [lateral and posterolateral columns (LPCs) fractures] in a prospective cohort. MATERIALS AND METHODS: From January 2007 through December 2010, a total of 65 patients with LPCs underwent dual-plate fixation via a combined anterior and posterior approach. The anterior and posterior approaches were the conventional anterolateral approach and a posteromedial inverted L-shaped approach, respectively, with the patients in a floating position. RESULTS: Ultimately, 41 patients were followed up for a mean period of 52.5 months. All fractures healed. The mean time to radiographic bony union was 15.2 weeks and the mean time to full weight-bearing was 18.7 weeks. No parameter associated with knee alignment changed significantly between immediately postoperation and 2 years postoperation. No collapse of the reduced articular surface was detected. Two years postoperation, the mean Hospital for Special Surgery score was 92.3; the mean Short Form-36 score was 90.1, and the mean range of knee motion was 1.7°-123.6° (extension-flexion). Two patients suffered dehiscence of the anterolateral incision and another suffered partial necrosis at the margin of the posteromedial incision postoperatively. All healed in response conservative treatment. Another two patients experienced numbness in the posteromedial inferior region of the calf. No implant loosening, breakage, fixation failure, or other complication was observed during follow-up. CONCLUSIONS: LPCs are not uncommon. Careful preoperative analysis of computed tomography images and impeccable preparation are necessary to avoid neglecting a posterolateral column fracture. It is inappropriate to generalize one scenario for all Schatzker type II fractures: a single approach cannot address all subtypes of these fractures. Dual-plate fixation via a combined approach is an effective treatment for LPCs.

Prognostic model and treatment choices for patients with primary intracranial central nervous system lymphoma: A population-based study.

BACKGROUND: Primary central nervous system lymphoma (PCNSL) is a non-Hodgkin lymphoma that occurs in the CNS. With the advancement of medical care, its prognosis and treatment have also undergone tremendous changes. This study aimed to construct a prognostic model and compare the effects of different treatments for intracranial PCNSL. METHODS: Cases diagnosed as PCNSL between 2004 and 2015 were obtained from the Surveillance, Epidemiology, and End Results (SEER) database. Data were analyzed using Kaplan-Meier method and Cox regression analysis. Nomogram was built and validated using the R program. RESULTS: A total of 2861 PCNSL patients were included in the analysis. Age, year of diagnosis, surgery and chemotherapy were independent predictors for both overall survival (OS) and cancer-specific survival (CSS). A nomogram was established to predict 3-, 5- and 10-year OS and CSS for patients. Receiver operating characteristic (ROC) curves and decision curve analysis (DCA) showed the nomogram had good predictive performance and clinical application value. We also revealed that gross total resection had significantly better OS and CSS than biopsy alone (P < 0.001). Patients who received only chemotherapy had the best prognosis and did not benefit from additional radiotherapy. CONCLUSION: We developed a nomogram to predict patient survival rates based on independent predictors. It is an effective tool to help clinicians make survival predictions. Our results showed that patients can benefit from gross total resection of tumor, if it is feasible, and chemotherapy. The role of radiotherapy remained to be further assessed.

Regulating Magnetic Behavior of Fe in Hematene by Defects to Improve Oxygen Evolution Reaction.

Two-dimensional hematene is earth-abundant and exhibits easy modulation with unique electronic properties, suggesting a promising role as an electrocatalyst for oxygen evolution reaction (OER). In this Letter, we propose a strategy to regulate the magnetic behavior of Fe atoms in hematene by introducing structural defects to enhance its OER activity. Hematene is proved to be thermodynamically stable at electrolyte pH values ≥3 under the OER working potential according to the Pourbaix diagram. Among all the defective structures, the most stable DVFe1-O defect exhibits superior OER activity, which originates from the unique spin state of the active Fe atom. We further propose a novel descriptor of the magnetic moment difference on active Fe to efficiently evaluate the OER activity. We believe that our strategy of combining the defect modulation in the geometric structure and spin-state control in the electronic configuration could provide a guideline to design highly active Fe-based electrocatalysts.

Interface engineering of heterogeneous transition metal chalcogenides for electrocatalytic hydrogen evolution.

MoS2 and MoSe2 are recognized as promising electrocatalysts for the hydrogen evolution reaction (HER), but the active sites are mainly located on the edge, limiting their electrochemical efficiency. Here we have introduced the 2H-1T' interface structures in MoSSe and MoS2-MoSe2 heterostructures to enhance the HER activity in the basal planes by using the density functional theory (DFT) calculations. The structural stability and electronic properties of different 2H-1T' interface structures are investigated and the HER activities are evaluated by using the H adsorption free energy (ΔG H). The H adsorption free energy along the interface boundaries is very close to zero, and the optimal sites for the HER are the S or Se atoms, which are bonded with three Mo atoms and located in the center of a hexagonal ring composed of three Mo atoms and three halogen atoms. Our study provides a different approach to activate the basal planes and efficiently improve the electrochemical HER performance of transition metal dichalcogenide materials.

m6A-Related lncRNAs Predict Overall Survival of Patients and Regulate the Tumor Immune Microenvironment in Osteosarcoma.

Background: m6A-related lncRNAs have demonstrated great potential tumor diagnostic and therapeutic targets. The goal of this work was to find m6A-regulated lncRNAs in osteosarcoma patients. Method: The Cancer Genome Atlas (TCGA) database was used to retrieve RNA sequencing and medical information from osteosarcoma sufferers. The Pearson's correlation test was used to identify the m6A-related lncRNAs. A risk model was built using univariate and multivariable Cox regression analysis. Kaplan-Meier survival analysis and receiver functional requirements were used to assess the risk model's performance (ROC). By using the CIBERSORT method, the associations between the relative risks and different immune cell infiltration were investigated. Lastly, the bioactivities of high-risk and low-risk subgroups were investigated using Gene Set Enrichment Analysis (GSEA). Result: A total of 531 m6A-related lncRNAs were obtained from TCGA. Seven lncRNAs have demonstrated prognostic values. A total of 88 OS patients were separated into cluster 1, cluster 2, and cluster 3. The overall survival rate of OS patients in cluster 3 was more favorable than that of those in cluster 1 and cluster 2. The average Stromal score was much higher in cluster 1 than in cluster 2 and cluster 3 (P < 0.05). The expression levels of lncRNAs used in the construction of the risk prediction model in the high-risk group were generally lower than those in the low-risk group. Analysis of patient survival indicated that the survival of the low-risk group was higher than that of the high-risk group (P < 0.0001) and the area under the curve (AUC) of the ROC curve was 0.719. Using the CIBERSORT algorithm, the results revealed that Macrophages M0, Macrophages M2, and T cells CD4 memory resting accounted for a large proportion of immune cell infiltration. By GSEA analysis, our results implied that the high-risk group was mainly involved in unfolded protein response, DNA repair signaling, and epithelial-mesenchymal transition signaling pathway and glycolysis pathway; meanwhile, the low-risk group was mainly involved in estrogen response early and KRAS signaling pathway. Conclusion: Our investigation showed that m6A-related lncRNAs remained tightly connected to the immunological microenvironment of osteosarcoma tumors, potentially influencing carcinogenesis and development. The immune microenvironment and immune-related biochemical pathways can be changed by regulating the transcription of M6A modulators or lncRNAs. In addition, we looked for risk-related signaling of m6A-related lncRNAs in osteosarcomas and built and validated the risk prediction system. The findings of our current analysis will facilitate the assessment of outcomes and the development of immunotherapies for sufferers of osteosarcomas.

Thermal migration towards constructing W-W dual-sites for boosted alkaline hydrogen evolution reaction.

Tungsten carbides, featured by their Pt-like electronic structure, have long been advocated as potential replacements for the benchmark Pt-group catalysts in hydrogen evolution reaction. However, tungsten-carbide catalysts usually exhibit poor alkaline HER performance because of the sluggish hydrogen desorption behavior and possible corrosion problem of tungsten atoms by the produced hydroxyl intermediates. Herein, we report the synthesis of tungsten atomic clusters anchored on P-doped carbon materials via a thermal-migration strategy using tungsten single atoms as the parent material, which is evidenced to have the most favorable Pt-like electronic structure by in-situ variable-temperature near ambient pressure X-ray photoelectron spectroscopy measurements. Accordingly, tungsten atomic clusters show markedly enhanced alkaline HER activity with an ultralow overpotential of 53 mV at 10 mA/cm2 and a Tafel slope as low as 38 mV/dec. These findings may provide a feasible route towards the rational design of atomic-cluster catalysts with high alkaline hydrogen evolution activity.

Flexible, All-Inorganic CsPbBr3 Perovskite Solar Cells Tailored by Heat-resistant Muscovite Substrates.

All-inorganic CsPbBr3 perovskite solar cells (PSCs) have attracted tremendous attention, owing to their excellent stability and rising power conversion efficiency. However, the mechanical flexibility of these solar cells has ground to a standstill because of the high-temperature requirement for ideal CsPbBr3 perovskite films. In this study, a flexible CsPbBr3 PSC with an efficiency of 5.71 % has been made by means of fabricating a heat-resistant conductive muscovite substrate, which demonstrates very high mechanical flexibility with nearly unchanged resistance even after 4000 bending cycles (12000 cycles of concave and convex bending for PSCs), owing to the weak van der Waals force and layered structure. Implementation of the muscovite substrate enables the fabrication of flexible PSCs under high-temperature conditions, providing a new path to increase the efficiency without lowering the crystallization temperature of state-of-the-art electron-transporting materials and perovskite films in the future.

Construction of Single-Atom Platinum Catalysts Enabled by CsPbBr3 Nanocrystals.

Lead halide perovskite nanocrystals (CsPbX3 NCs) have been regarded as promising materials in photocatalysis. Combining metal single atoms with CsPbX3 NCs may be a practical way in exploring perovskite-based catalysts. However, such hybrids have not been achieved experimentally yet, mainly due to the weak interaction between the metal atom and the CsPbX3 surface. Here, we demonstrate that Pt single atoms can be deposited on CsPbBr3 NCs through a photoassisted approach, in which the surface was partially oxidized first, followed by the anchoring of Pt single atoms through the formation of Pt-O and Pt-Br bonds. The deposition of Pt single atoms can significantly change the photophysical properties of CsPbBr3 NCs by inducing the generation of deep trap states in the band gap. The as-prepared Pt-SA/CsPbBr3 can be used as efficient and durable catalysts for photocatalytic semi-hydrogenation of propyne. A CsPbBr3 nanocrystal might be a suitable substrate for anchoring other metal single atoms, such as Cu, Au, Ag, Pd, and so on.

Dual Functionalization of Electron Transport Layer via Tailoring Molecular Structure for High-Performance Perovskite Light-Emitting Diodes.

Great progress in modification and optimization of emission layer (EML) in perovskite light-emitting diodes (PeLEDs) results in a significant improvement in device efficiency. However, so far, less attention has been paid to the exploration of hole/electron injection and transporting layers to maximize the utilization of charge carriers for efficient and stable PeLEDs. At present, low electron mobility of electron transport layer (ETL) causes an unbalanced charge injection, and the defects at the ETL/perovskite interface limit the formation and utilization of generated excitons. Here, a series of compounds (BPBiTP, BPBiPN, and BPBiPA) flanked by diphenyl-1H-benzo[d]imidazole end groups have been developed as ETL materials, where the bridging units (benzene, naphthalene, anthracene) are manipulated to achieve dual functionality, namely, the high charge carrier mobility and effective passivation of perovskite surface. The coordinating end groups effectively reduce the trap state at the interface of ETL and EML due to their strong nucleophilic quality. H-aggregation of anthracene units and large transfer integral in BPBiPA lead to its superior electron mobility of 8.4 × 10-4 cm2 V-1 s-1 in the solid state, over 1 order of magnitude higher than that of the typical one (TPBi). Consequently, green PeLEDs with a maximum external quantum efficiency (EQE) of 19.7%, reduced efficiency roll-off, as well as extended operational lifetime have been achieved without any outcoupling technique. Our result demonstrated that optimization of ETL materials via improving both passivation capability and electron mobility is a powerful strategy for producing high-performance PeLEDs.

Scalable noninjection phosphine-free synthesis and optical properties of tetragonal-phase CuInSe2 quantum dots.

Phosphine-free synthesis of CISe quantum dots (QDs) is highly desirable, yet it has been challenging. The main difficulty lies in achieving phosphine-free Se precursors. Most reported protocols for the synthesis of size-confined CISe QDs highly depend on the use of air-sensitive, toxic, and expensive alkylphosphines to prepare reactive Se precursors and to confine particle growth. Herein, we present a new amine/thiol combination-based route to Se precursors that may enable a general synthesis of phosphine-free selenide QDs. What's more, instead of the traditional "hot-injection" method, we also report the first one-pot noninjection synthesis of high quality CISe QDs enabled by our strategy. A very high chemical yield of ∼95% is demonstrated, as well as the facile gram-scale production of monodisperse CISe QDs. By simply adjusting the amount of 1-dodecanethiol used in the synthesis, we are able to produce CISe QDs with continuous tunability of the particle size from ∼2 nm to ∼10 nm, and hence their intrinsic optical properties.

Updated Three-Column Concept in surgical treatment for tibial plateau fractures - A prospective cohort study of 287 patients.

PURPOSE: This study introduces an updated Three-Column Concept for the classification and treatment of complex tibial plateau fractures. A combined preoperative assessment of fracture morphology and injury mechanism is utilized to determine surgical approach, implant placement and fixation sequence. The effectiveness of this updated concept is demonstrated through evaluation of both clinical and radiographic outcome measures. PATIENTS AND METHODS: From 2008 to 2012, 355 tibial plateau fractures were treated using the updated Three-Column Concept. Standard radiographic and computed tomography imaging are used to systematically assess and classify fracture patterns as follows: (1) identify column(s) injured and locate associated articular depression or comminution, (2) determine injury mechanism including varus/valgus and flexion/extension forces, and (3) determine surgical approach(es) as well as the location and function of applied fixation. Quality and maintenance of reduction and alignment, fracture healing, complications, and functional outcomes were assessed. RESULTS: 287 treated fractures were followed up for a mean period of 44.5 months (range: 22-96). The mean time to radiographic bony union and full weight-bearing was 13.5 weeks (range: 10-28) and 14.8 weeks (range: 10-26) respectively. The average functional Knee Society Score was 93.0 (range: 80-95). The average range of motion of the affected knees was 1.5-121.5°. No significant difference was found in knee alignment between immediate and 18-month post-operative measurements. Additionally, no significant difference was found in functional scores and range of motion between one, two and three-column fracture groups. Twelve patients suffered superficial infection, one had limited skin necrosis and two had wound dehiscence, that healed with nonoperative management. Intraoperative vascular injury occurred in two patients. Fixation of failure was not observed in any of the fractures treated. CONCLUSION: An updated Three-Column Concept assessing fracture morphology and injury mechanism in tandem can be used to guide surgical treatment of tibial plateau fractures. Limited results demonstrate successful application of biologically friendly fixation constructs while avoiding fixation failure and associated complications of both simple and complex tibial plateau fractures. LEVEL OF EVIDENCE: Level II, prospective cohort study.

Morphologic study of posterior articular depression in Schatzker IV fractures.

The Schatzker classification of tibial plateau fractures is widely accepted. Type IV fractures are medial tibial plateau fractures that are either split off as a wedge fragment or depressed and comminuted. Posterior articular surface depression in Schatzker type IV tibial plateau fractures can be seen as a unique variant that increases the difficulty of reduction of the articular surface. Its morphologic characteristics have not been fully studied, and the incidence is sometimes underestimated. The goal of this study was to evaluate the morphologic characteristics of posterior articular depression in Schatzker type IV fractures based on computed tomography measurements. From January 2009 to December 2011, the medical records, including digital radiologic data, of all patients treated for tibial plateau fracture at the authors' institution were retrospectively analyzed. Articular surface depression deeper than 5 mm was the criterion for study inclusion. The depression depth, precise location of the articular depression center, surface area percentage, and distance of the fracture gap to the depression center were calculated. One hundred fifteen cases of Schatzker type IV fracture were retrieved, and a total of 47.83% (55 of 115) cases had posterior articular surface depression. The average depth of the depressed articular surface was 12.41 mm, the surface area percentage was 20.15% of the entire tibial plateau, and the gap distance from the medial direction was 41.40 mm, 2.8 times longer than that from the posterior direction, which was 14.91 mm. Posterior articular surface depression occurs in nearly half of Schatzker type IV fractures, and the posterior approach provides more direct access to the depression than the medial approach.

Colloidal CuInS2 Quantum Dots as Inorganic Hole-Transporting Material in Perovskite Solar Cells.

To develop novel hole-transporting materials (HTMs) is an important issue of perovskite solar cells (PSCs), especially favoring the stability improvement and the cost reduction. Herein, we use ternary quantum dots (QDs) as HTM in mesoporous TiO2/CH3NH3PbI3/HTM/Au solar cell, and modify the surface of CuInS2 QDs by cation exchange to improve the carrier transport. The device efficiency using CuInS2 QDs with a ZnS shell layer as HTM is 8.38% under AM 1.5, 100 mW cm(-2). The electrochemical impedance spectroscopy suggested that the significantly enhanced performance is mainly attributed to the reduced charge recombination between TiO2 and HTM. It paves a new pathway for the future development of cheap inorganic HTMs for the high efficiency PSCs.

SnX (X = S, Se) thin films as cost-effective and highly efficient counter electrodes for dye-sensitized solar cells.

Solution-deposited SnSe and SnS thin films demonstrate excellent electrocatalytic activity toward the triiodide reduction in dye-sensitized solar cells (DSCs), even better than that of the conventional noble Pt electrode used in DSCs. An enhanced photovoltaic efficiency with the maximum value of 9.4% was thus achieved, higher than that with Pt (9.0%).

A posterior reversed L-shaped approach for the tibial plateau fractures-A prospective study of complications (95 cases).

PURPOSE: This study was aiming to investigate intraoperative and postoperative complications and outcomes of a posterior reversed L-shaped approach (PRLA) in the treatment of the tibial plateau fractures. METHODS: Inclusion criterion was tibial plateau fractures treated through the PRLA either separated or combined with other approaches. Main exclusion criterion was poly-trauma patients. Ninety-five patients with tibial plateau fractures from a prospectively collected database were included and followed in this study. The intraoperative and postoperative complications consisted of vascular and nerve injury, wound infection, dehiscence, haematoma, nonunion, skin necrosis and skin paresthesia. Hospital for Special Surgery Knee Score (HSS) was adopted to evaluate patients' knee function while Short Form 36 Health Survey (SF-36) was used to investigate the patients' general health status. RESULTS: Patients' average age was 46.2 years old (range, 22.0-89.0). The fractures were mainly from high energy injuries involving posterior (and medial) column. 78 of 95 cases were combined with an additional anterolateral approach due to the lateral column involvement. The average follow-up was 52.0 months (range, 12.4-102.6). The total complications rate was 4.2% (4/95). Intraoperative complications occurred in two patients (2.1%). One suffered a popliteal artery injury resulted from an antero-posteriorly drilled K-wire. The patient had a loss of 7° knee extension at one year's follow-up. The other endured an injury of nutrient vessel within the medial head of gastrocnemius. Postoperative skin paresthesia occurred in two patients (2.1%). The other complications associated with the PRLA were not observed. The mean HSS score was 96.1 (range, 80-100). The mean SF-36 score was 94.2 (range, 80-100). CONCLUSIONS: The posterior reversed L-shaped approach allows satisfied visualization of the medial and posterior tibial plateau and has promising clinical results with low complication occurrence. It can be recommended as a routine approach for the treatment of the tibial plateau fractures involving the posterior column.