Objective: The objective of the study is to evaluate the safety and efficacy of three different treatment methods for pediatric ulnar and radial double fractures. Methods: 120 children with ulnar and radial double fractures were included in the study. According to the different treatment plans, children were divided into three groups: manual reduction, splint external fixation, double elastic intramedullary fixation, and double plate fixation. Surgical indicators, radiological results, clinical efficacy, and complications were evaluated and compared among the groups. Results: The average hospital stay and operation time were significantly longer in the double plate internal fixation group compared to the other two groups. The double elastic intramedullary nailing group showed a higher fracture healing rate at 3 months compared to the other groups. There were no significant differences in clinical efficacy among the three groups. Complications were observed in all groups but did not show significant statistical differences. Conclusion: Double elastic intramedullary nailing fixation demonstrated favorable outcomes in terms of surgical indicators and fracture healing rates for pediatric ulnar and radial double fractures.
Objetivo: Evaluar la seguridad y eficacia de tres métodos de tratamiento diferentes para las fracturas dobles cubital y radial pediátricas. Métodos: Se incluyeron en el estudio 120 niños con fracturas dobles de cúbito y radio. Según los diferentes planes de tratamiento, los niños se dividieron en tres grupos: reducción manual, fijación externa con férula, fijación intramedular doble elástica y fijación con doble placa. Se evaluaron y compararon entre los grupos indicadores quirúrgicos, resultados radiológicos, eficacia clínica y complicaciones. Resultados: La estancia hospitalaria promedio y el tiempo de operación fueron significativamente más prolongados en el grupo de fijación interna con doble placa en comparación con los otros dos grupos. El grupo de clavo intramedular elástico doble mostró una mayor tasa de curación de la fractura a los 3 meses en comparación con los otros grupos. No hubo diferencias significativas en la eficacia clínica entre los tres grupos. Se observaron complicaciones en todos los grupos pero no mostraron diferencias estadísticas significativas. Conclusión: La fijación con clavo intramedular elástico doble demostró resultados favorables en términos de indicadores quirúrgicos y tasas de curación de fracturas pediátricas dobles cubital y radial.
High-performance proton exchange membrane (PEM) is crucial for the proton exchange membrane fuel cell (PEMFC). Herein, a novel "self-enhanced" PEM is fabricated for the first time, which is composed of perfluorinated sulfonic acid (PFSA) resin and its own nanofibers as reinforcement. With this strategy, the interfacial compatibility issue of conventional fiber-reinforced membranes is fully addressed and up to 80 wt% loading of PFSA nanofibers can be incorporated. Furthermore, on account of chain orientation within the PFSA nanofiber, single fiber exhibits super-high conductivity of 1.45 S cm-1, leading to state-of-the-art proton conductivity (1.1 S cm-1) of the as-prepared "self-enhanced" PEM so far, which is an order of magnitude increase compared with the bulk PFSA membrane (0.29 S cm-1). It surpasses any commercial PEM including the popular GORE-SELECT and Nafion HP membranes and is the only PEM with conductivity at 100 S cm-1 level. In addition, the mechanical strength and swelling ratio of membranes are both substantially improved simultaneously. Based on the high-performance "self-enhanced" PEM, high peak power densities of up to 3.6 W cm-2 and 1.7 W cm-2 are achieved in H2-O2 and H2-Air fuel cells, respectively. This strategy can be applied in any polymeric electrolyte membrane.
Transition metal oxides, highly motivated anodes for lithium-ion batteries due to high theoretical capacity, typically afflict by inferior conductivity and significant volume variation. Architecting heterogeneous structures with distinctive interfacial features can effectively regulate the electronic structure to favor electrochemical properties. Herein, an engineered carbon-coated nanosized Fe3 O4 /Cr2 O3 heterostructure with multiple interfaces is synthesized by a facile sol-gel method and subsequent heat treatment. Such ingenious components and structural design deliver rapid Li+ migration and facilitate charge transfer at the heterogeneous interface. Simultaneously, the strong coupling synergistic interactions between Fe3 O4 , Cr2 O3 , and carbon layers establish multiple interface structures and built-in electric fields, which accelerate ion/electron transport and effectively eliminate volume expansion. As a result, the multi-interface heterostructure, as a lithium-ion battery anode, exhibits superior cycling stability maintaining a reversible capacity of 651.2 mAh g-1 for 600 cycles at 2 C. The density functionaltheory calculations not only unravel the electronic structure of the modulation but also illustrate favorable lithium-ion adsorption kinetics. This multi-interface heterostructure strategy offers a pathway for the development of advanced alkali metal-ion batteries.
Tuning the electroactive surface species of electrocatalysts remains a significant challenge for achieving highly efficient oxygen evolution reactions. Herein, we propose an innovative in situ leaching strategy, modulated by cationic oxidation, to achieve active self-reconstruction of these catalysts. Vanadium is introduced as a cation into Ni3S2 and oxidized under low oxidative potential, leading to subsequent leaching into the electrolyte and triggering self-reconstruction. The structural evolution from V-Ni3S2 to Ni(OH)2 and subsequently to NiOOH is identified by operando Raman as a three-step transition. In contrast, V-free Ni3S2 is unable to bypass the thermodynamically predicted nickel oxysulfide products to transform into active NiOOH. As a result, the self-restructured V-Ni3S2 only needs an ultralow overpotential of 155 mV at 10 mA cm-2, outperforming V-free Ni3S2 and many other advanced catalysts. This work provides new guidelines for manipulating in situ leaching to modulate the self-reconstruction of catalysts.
High strength aluminum alloys are widely used but their strength is reduced as nano-precipitates coarsen rapidly in medium and high temperatures, which greatly limits their application. Single solute segregation layers at precipitate/matrix interfaces are not satisfactory in stabilizing precipitates. Here we obtain multiple interface structures in an Al-Cu-Mg-Ag-Si-Sc alloy including Sc segregation layers, C and L phases as well as a newly discovered χ-AgMg phase, which partially cover the θ' precipitates. By atomic resolution characterizations and ab initio calculations, such interface structures have been confirmed to synergistically retard coarsening of precipitates. Therefore, the designed alloy shows the good combination of heat resistance and strength among all series of Al alloys, with 97% yield strength retained after thermal exposure, which is as high as 400 MPa. This concept of covering precipitates with multiple interface phases and segregation layers provides an effective strategy for designing other heat resistant materials.
High-performance conversion transition metal oxides are strong candidates for advanced anode materials for lithium-ion batteries. However, the poor intrinsic conductivity and the large volume changes during battery operation are important constraints to its practical application. The heterogeneous atom doping strategy is an important way to modulate the electronic structure and surface states of the host materials. Herein, theoretical calculations reveal that heteroatomic Ti doping and its ionic or electronic compensation mechanisms can well modulate the electronic structure of Fe2O3 and change the surface Li-ion affinity. A Ti concentration gradient modification strategy for Fe2O3 is proposed to construct high-performance electrode materials. As a Li-ion battery anode, Ti concentration gradient-doped Fe2O3 achieves excellent long-cycle stability, with a reversible capacity of 1001.9 mAh g-1 at 1 A g-1 for 1200 cycles, and even maintains a reversible specific capacity compared to the theoretical capacity of commercial graphite electrodes at 2 A g-1 for 2000 cycles. This combination of theoretical calculations and experiments offers ways to intelligently design and develop alkali metal ion batteries.
The poor cycling performance of Li-rich cathode Li2MnO3, a promising cathode for next-generation Li-ion batteries, limits its commercial applications. Transition metal (TM) doping is widely applied to optimize the electrochemical performance of Li2MnO3, where the d valence electrons of the TM play a crucial role. Nevertheless, the rule of the doping effect of TM with various numbers of d electrons has not been well summarized. In this work, 4d-TMs (Zr, Nb, Mo, Ru and Rh) are selected as dilute doping elements for Li2MnO3 to evaluate their effect on the performance of Li2MnO3 through first-principles calculations. The calculations indicate that as the number of 4d electrons increases, the doped TM transforms from an electrochemically inert state (Zr and Nb) to an electrochemically active state (Mo, Ru and Rh) in Li2MnO3. Meanwhile, the orbital hybridization between the 4d electrons of the TM and the 2p electrons of O becomes stronger from Zr to Rh, which promotes the co-oxidation of the TM and O for charge compensation and alleviates the excessive oxidation of O, thus enhancing the stability of O. Moreover, the oxidation of the doped TM and lattice Mn during charging can trigger a decrease in the initial average delithiation potential. Although the 4d-TMs exhibit slight promoting or inhibiting effects on Li diffusion, no obvious rule related to the number of d electrons has been found. Our work highlights the rule of the doping effect of TMs with different 4d electrons on the electrochemical performance of Li2MnO3 and would facilitate a better design of Li2MnO3 cathode materials.
Ultra-tough and heat-resistant poly(l-lactide)/core-shell rubber (PLLA/CSR) blends were fabricated by utilizing stereocomplex (SC) crystallites to effectively regulate the CSR distribution in PLLA matrix. Linear and 3-11 armed poly(d-lactide)s (PDLAs) were synthesized and then melt-mixed with PLLA/CSR blend. Interestingly, the incorporated PDLA chains could collaborate with PLLA chains to form dense SC crystallites network in PLLA/PDLA/CSR blends, thus inducing the CSR particles to transform from uniform distribution structure to network-like structure. With increasing the PDLA arm numbers, the size of CSR clusters in the network-like structure first increased and then decreased, and the continuity of the network-like structure first remained at a high level and then decreased obviously. The formation of CSR network-like structure could remarkably improve the impact strength of PLLA/PDLA/CSR blends without deteriorating their strength and modulus (compared with PLLA/CSR blend), and the CSR network-like structure with larger-sized CSR clusters and higher continuity could help obtain higher impact strength (78.3 kJ/m2). Moreover, the heat resistance of PLLA/PDLA/CSR blends could also be significantly improved (the highest Vicat softening temperature was 131 °C) by the SC crystallites network and CSR network-like structure. This work provides an effective strategy for controlling the rubber network-like morphology and thereby preparing high-performance PLLA materials.
Hot Temperature , Polyesters , Crystallization , Stereoisomerism , Polyesters/chemistry
PURPOSE: To investigate the clinical efficacy of accelerated rehabilitation surgery for the treatment of Gustilo type IIIA/B open tibiofibular fracture with emergency stage I debridement, internal fracture fixation, bone grafting, coverage of the wound surface with a muscle flap combined with vacuum sealing drainage (VSD), and internal and lateral leg reduction. METHODS: A retrospective analysis was performed on the clinical data of 15 patients with Gustilo type IIIA/B open tibiofibular fracture who were admitted to the Affiliated Zhongshan Hospital of Dalian University from January 2015 to December 2018. There were 12 males and 3 females. The patients ranged in age from 20 to 62 years, with an average of 39.5 years. After admission, the patients underwent stage I emergency debridement (including exploration and repair of nerves and tendons), open reduction and internal fixation of the tibia and fibula, iliac bone grafting, muscle flap and VSD coverage of the bone defect, complete tensioning of the calf inside and outside, tibia-sparing incision before healing, and stage II free skin grafting. Patients were followed up periodically to observe muscle flap survival, fracture healing time, length of hospitalization, wound healing time, delayed union, bone nonunion, osteomyelitis and other complications. At the last follow-up, the Johner-Wruhs criteria were used to evaluate the rate of good functional recovery from tibial shaft fracture, fracture healing quality was evaluated by the Merchant score, and limb function was evaluated by the LEFS. RESULTS: All 15 cases were followed up for 12-32 months, with an average of 22.8 months. All the fractures healed; the range of healing time was 14-30 weeks (mean 18.5 weeks). The length of hospitalization was 25.1 ± 7.6 days, and wound healing took 12.2 ± 2.0 days. None of the patients had complications such as osteomyelitis infection. When the Johner-Wruhs evaluation criteria for functional recovery from tibial shaft fracture were applied at the last follow-up, the outcomes were as follows: excellent in 13 cases, good in 1 case and fair in 1 case, for an excellent and good rate of 93.3%. When fracture healing was evaluated according to the Merchant scoring standard, the outcomes were as follows: excellent in 12 cases, good in 1 case, fair in 1 case, and poor in 1 case, for an excellent and good rate of 86.7%. The mean LEFS score of the affected limb at the last follow-up was 70 (59-80). CONCLUSION: For Gustilo type IIIA/B open tibiofibular fractures, emergency stage I debridement, internal fixation of the fracture, bone grafting, coverage of the wound with a muscle flap, complete tensioning of the calf inside and outside, and application of VSD can improve the repair of leg soft-tissue defects, shorten hospitalization time, promote fracture healing, and effectively reduce infection and complications related to bone exposure. More importantly, this treatment protocol provides effective wound repair, guarantees the recovery of limb function, significantly speeds up recovery, and improve patients' quality of life.
Transition metal (TM) doping is widely applied to optimize the electrochemical performance of Li2MnO3, a promising cathode material of next-generation Li-ion batteries. The effect of doping on the performance of Li2MnO3 can vary with the elemental period of the doped TM. However, the rules of the different effects have not been well summarized, especially for TM elements within the same group. In this work, the effects of TM element (Cr, Mo, and W in group VIB) dilute doping on the electrochemical performance of Li2MnO3 are investigated through first-principles calculations. The results show that Mo and W can induce more obvious local lattice distortion. Although Cr, Mo and W doping can improve the electrochemical activity of Li2MnO3, they modify the charge compensation mechanism in different ways. At the initial stage of delithiation, both Cr and O undergo significant oxidation, and Mo can act as the main oxidation center, while W can trigger the electrochemical activity of Mn around it. The O ions around Mo and W are more stable during the delithiation due to the mild oxidation and the strong bonding of Mo-O and W-O. Furthermore, Cr, Mo and W dilute doping can promote the interlayer diffusion of Li at the initial charging state, which is gradually enhanced with the increase of the period of the doped elements, but Mo and W doping would hinder the intralayer diffusion of Li near the doping sites during further delithiation process. Our results highlight the difference in the effects of TM (in the same group) doping on the performance of Li2MnO3 and would facilitate fast and good design of Li-rich cathodes.
Myeloid lineage cells present the latent form of transforming growth factor-ß1 (L-TGF-ß1) to the membrane using an anchor protein LRRC33. Integrin αVß8 activates extracellular L-TGF-ß1 to trigger the downstream signaling functions. However, the mechanism designating the specificity of TGF-ß1 presentation and activation remains incompletely understood. Here, we report cryo-EM structures of human L-TGF-ß1/LRRC33 and integrin αVß8/L-TGF-ß1 complexes. Combined with biochemical and cell-based analyses, we demonstrate that LRRC33 only presents L-TGF-ß1 but not the -ß2 or -ß3 isoforms due to difference of key residues on the growth factor domains. Moreover, we reveal a 2:2 binding mode of integrin αVß8 and L-TGF-ß1, which shows higher avidity and more efficient L-TGF-ß1 activation than previously reported 1:2 binding mode. We also uncover that the disulfide-linked loop of the integrin subunit ß8 determines its exquisite affinity to L-TGF-ß1. Together, our findings provide important insights into the specificity of TGF-ß1 signaling achieved by LRRC33 and integrin αVß8.
Integrin alphaV , Integrins/metabolism , Latent TGF-beta Binding Proteins/metabolism , Transforming Growth Factor beta1 , Humans , Integrin alphaV/metabolism , Signal Transduction , Transforming Growth Factor beta1/metabolism
The eutectic Ga91.6Sn8.4 liquid metal could serve as the anode in Li-ion batteries to avoid dendrite growth issue and volume expansion, and maintain a good cycle life. However, the microstructure and the basic physical properties of the lithiated Ga91.6Sn8.4 are ignored in experiments and still unclear. In this work, we assume that a disordered structure is formed in the initial stage of lithiation of Ga91.6Sn8.4, and the structure, equilibrium density, thermal expansion coefficient, mixing enthalpy, self-diffusion coefficient and viscosity of the disordered Li-Ga-Sn system are investigated systematically by ab initio molecular dynamics. The radial distribution function, structure factor and bond angle distribution function are calculated to obtain local structure information. Our calculations show that the lithiation of Ga91.6Sn8.4 is exothermic, and for most cases, the diffusion coefficients for Li, Ga and Sn decrease with increasing Li content. Based on structural information and diffusion coefficients, we reveal that the lithiation of Ga91.6Sn8.4 will make the liquid Ga91.6Sn8.4 alloy form a solid-like structure. With the increase of Li content, it is more likely to form a solid-like structure. Furthermore, our simulations reveal that the chemical interaction of Li-Sn and Li-Ga is stronger than that of Ga-Sn, and Li is prone to combine with Sn firstly in the lithiation process of Ga91.6Sn8.4.
Metal oxides are a promising candidate for lithium-ion battery (LIB) anodes due to their high theoretical capacity and long cycle life but also face inherent poor conductivity and volume variation, making them difficult to promote the application. The cation substitution strategy is an important means to facilitate improved rate and cycling performance. However, the effect of cation substitution on electrochemical activity is multivariate and complex, and a comprehensive and systematic analysis is essential for understanding the relationship between components and properties. Herein, the aliovalent heterogeneous Cr-substituted MnO was used as a model to systematically investigate the effects of Cr substitution on the crystal structure, electron distribution, defect construction, and electrochemical reaction processes. Theoretical calculations and experimental results reveal that Cr substitution can effectively modulate the electronic structure, build a built-in electric field, generate cationic defects, and catalyze the electrochemical reaction process, thereby improving the electrode kinetics and electrochemical activity of active materials. When the optimized Mn0.94Cr0.06O was used as the anode for LIBs, a reversible capacity of 1547.3 mAh g-1 was obtained after 450 cycles at a current density of 1 C (1 C = 756 mA g-1 for half-cells), and a reversible capacity of up to 1126.2 mAh g-1 could be maintained even after 700 cycles at a current density of 2 C. The assembled Mn0.94Cr0.06O//LiCoO2 full cell further confirms the scalability of the heterogeneous atom substitution strategy.
BACKGROUND: Simultaneous dislocation of the elbow, radioulnar joint and proximal radius fracture with rotary noose injury to the medial ulna tubercle is extremely rare. An emergency surgery was performed to reduce it. The radial head with the backbone was reset after two hammers were fixed, then the radial capitulum safety was fixed with a locking plate. After the ulnar instability was examined, two Kirschner wires were drilled percutaneously to fix the elbow flexion at 100° under closed reduction, and two Kirschner wires were drilled percutaneously to fix the ulnar joint. Good follow-up results were achieved. To the best of our knowledge, this is the first report on this particular type of injury and on this approach to treating this type of injury. CASE PRESENTATION: We report the case of a 36-year-old male, who extended and landed on his left hand to protect his child in right arm before felling, resulting in severe pain and deformity of his left elbow and wrist and loss of movement in these joints. X-ray examination found proximal distal radioulnar joints, a proximal radial fracture and a dislocation bowstring in the ulna nodule. For a timely diagnosis in an emergency open reduction situation, accurate judgment of this injury is highly important. After 12 months of postoperative follow-up, the patient was symptom-free, and radiographs showed fracture healing. CONCLUSION: We performed emergency reduction and internal fixation of the elbow and successfully saved elbow function, no stability decrease and movement restriction. This case also provides a new reference for the treatment of this type of elbow fracture dislocation.
Elbow Injuries , Elbow Joint , Joint Dislocations , Radius Fractures , Adult , Child , Elbow , Elbow Joint/surgery , Forearm , Humans , Joint Dislocations/diagnostic imaging , Joint Dislocations/surgery , Male , Radius Fractures/diagnostic imaging , Radius Fractures/surgery , Wrist Joint
For high-performance anion exchange membrane fuel cells (AEMFCs), the anion exchange membrane (AEMs) should be as thin as possible to reduce the ohmic resistance. However, the mechanical stability of ultrathin AEMs cannot be guaranteed, as well as a huge risk of gas (H2 &O2 ) permeation. In this work, composite AEMs based on ultrahigh molecular weight polyethylene (UHMWPE) are prepared by in situ bulk polymerization. The as-prepared composite membranes can be as thin as 4 µm, and possess super high strength beyond 150 MPa. It also shows extremely low hydrogen permeation, low water uptake, low dimensional swelling, high conductivity, and good alkaline stability. In addition, the fuel cell performance based on the ultrathin composite AEMs exhibits outstanding peak power density of 1014 and 534 mW cm-2 for H2 -O2 and H2 -Air (CO2 -free) at 65 °C, respectively, as well as good short-term durability.
Heterogeneous atoms substitution is an efficient method for promoting Li+ storage of transition metal oxides. Herein, a series of Fe-substituted MnO solid solutions with different Fe contents are synthesized by a feasible solid-phase method. The synergistic effects between heterogeneous atoms and rich vacancies are synchronously obtained, which hold distinctive electronic structures and substantial active sites. When optimized Mn0.55 Fe0.45 O solid solution as anodes for lithium-ion batteries, pre-prepared electrodes exhibit reversible lithium storage of 1286.9 mAh g-1 at 1 A g -1 after 400 cycles and even 628.1 mAh g-1 at 2 A g-1 after 1000 cycles. The LiCoO2 //Mn0.55 Fe0.45 O full cells are assembled, achieving the reversible capacity of 130.2 and 111.3 mAh g-1 after 150 cycles at 0.1 and 0.2 A g-1 , respectively. Density functional theory calculations also authenticate that the electrochemical activity can be markedly boosted by the heterogeneous atoms substituted Mn1 -x Fex O solid solution.
As a promising hydrogen storage material, sodium borohydride (NaBH4) exhibits superior stability in alkaline solutions and delivers 10.8 wt.% theoretical hydrogen storage capacity. Nevertheless, its hydrolysis reaction at room temperature must be activated and accelerated by adding an effective catalyst. In this study, we synthesize Co nanoparticles supported on bagasse-derived porous carbon (Co@xPC) for catalytic hydrolytic dehydrogenation of NaBH4. According to the experimental results, Co nanoparticles with uniform particle size and high dispersion are successfully supported on porous carbon to achieve a Co@150PC catalyst. It exhibits particularly high activity of hydrogen generation with the optimal hydrogen production rate of 11086.4 mLH2âmin-1âgCo-1 and low activation energy (Ea) of 31.25 kJ mol-1. The calculation results based on density functional theory (DFT) indicate that the Co@xPC structure is conducive to the dissociation of [BH4]-, which effectively enhances the hydrolysis efficiency of NaBH4. Moreover, Co@150PC presents an excellent durability, retaining 72.0% of the initial catalyst activity after 15 cycling tests. Moreover, we also explored the degradation mechanism of catalyst performance.
OBJECTIVE: To compare the clinical efficacy of percutaneous minimally invasive reduction combined with external fixation and a tarsal sinus approach to treat Sanders type II and III intra-articular calcaneal fractures. METHODS: The clinical data of 64 patients with Sanders type II and III calcaneal fractures admitted to our hospital from January 2010 to January 2016 were retrospectively analyzed; data includedage, sex, body mass index. According to the surgical method, they were divided into the percutaneous minimally invasive reduction with internal and external fixation group (30 cases) and the tarsal sinus approach group (34 cases).The two groups of patients were compared in terms of the time tosurgery, length of hospital stay, intraoperative blood loss, operative duration, complications, radiographic features, including the heel bone length, width, height, Bohlerangle, Gissane angle, and calcaneal varus angle, and clinical efficacy indicators, including the American Orthopedic Foot and Ankle Society (AOFAS) score, the visual analog scale (VAS) pain score, health survey profile (SF-36) score and Maryland ankle function score. RESULTS: Patients in both groups were followed up for 12 to 50 months, with an average of 24.8 months.Bony union was achieved in all cases. The time to surgery, length of hospitalstay, intraoperative blood loss and incidence of incision-related complications were significantly lower in the percutaneous minimally invasive medial external fixation group than in the tarsal sinus group (P < 0.01). At the last follow-up, the calcaneal length, width, and height, Bohler angle, Gissane angle, and varus angle were significantly increased in both groups (P < 0.01), the calcaneal width was significantly lower after than before surgery (P < 0.01), and there were no statistically significant differences between the two groups (P > 0.05). As measures of clinical efficacy, the AOFAS, VAS, SF-36 and Maryland scores were 85.28 ± 8.21, 0.84 ± 1.21, 82.95 ± 3.25 and 83.56 ± 3.32, respectively, at the last follow-up in the percutaneous minimally invasive medial external fixation group and 83.32 ± 7.69, 1.85 ± 1.32, 80.71 ± 5.42, and 81.85 ± 2.41 in the tarsal sinus group, respectively, with no significant differences between the two groups (P > 0.05). CONCLUSION: Under the condition of a good command of surgical indications and surgical skills, the use of plastic calcaneal forceps for percutaneous minimally invasive reduction combined with medial external fixation for the treatment of Sanders type II and III intra-articular calcaneal fractures can achieve similar clinical effects as the tarsal sinus approach. However, the use of plastic calcaneal forceps for percutaneous minimally invasive reduction combined with internal and external fixation has advantages, such as fewer complications, less bloodloss, and a shorter operation, and thus has good safety and is worthy of clinical promotion.
Calcaneus/injuries , Calcaneus/surgery , External Fixators , Fracture Fixation, Internal/methods , Fractures, Bone/surgery , Intra-Articular Fractures/surgery , Adult , Female , Humans , Male , Middle Aged , Pain Measurement , Surgical Instruments , Surveys and Questionnaires
The mammalian target of rapamycin (mTOR) is a serine-threonine kinase involved in cellular innate immunity, metabolism, and senescence. FK506-binding protein 12 (FKBP12) inhibits mTOR kinase activity via direct association. The FKBP12-mTOR association can be strengthened by the immunosuppressant rapamycin, but the underlying mechanism remains elusive. We show here that the FKBP12-mTOR association is tightly regulated by an acetylation-deacetylation cycle. FKBP12 is acetylated on the lysine cluster (K45/K48/K53) by CREB-binding protein (CBP) in mammalian cells in response to nutrient treatment. Acetyl-FKBP12 associates with CBP acetylated Rheb. Rapamycin recruits SIRT2 with a high affinity for FKBP12 association and deacetylation. SIRT2-deacetylated FKBP12 then switches its association from Rheb to mTOR. Nutrient-activated mTOR phosphorylates IRF3S386 for the antiviral response. In contrast, rapamycin strengthening FKBP12-mTOR association blocks mTOR antiviral activity by recruiting SIRT2 to deacetylate FKBP12. Hence, on/off mTOR activity in response to environmental nutrients relies on FKBP12 acetylation and deacetylation status in mammalian cells.
Spinel LiMn2O4 has attracted wide attention due to its advantages of a high-voltage plateau, good capacity, environmental friendliness, and low cost. Due to different experimental synthesis methods and conditions, there are many intrinsic point defects in LiMn2O4. By means of first-principles calculations based on a reasonable magnetic configuration, we studied the formation energies, local structures, and charge compensation mechanism of intrinsic point defects in LiMn2O4. The formation energies of defects under the assumed O-rich equilibrium conditions were examined. It was found that O, Li, and Mn vacancies, Mn and Li antisites, and Li interstitial could appear in the lattice at some equilibrium conditions, but Mn interstitial is hard to form. The charge was compensated mainly by adjusting the oxidation state of Mn around the defect, except for the defects at the 8a Wyckoff site. The binding energies between point defects were calculated to shed light on the clustering of point defects. Furthermore, the diffusion of Li ions around the defects was discussed. Cation antisites led to a decrease of the Li diffusion barrier but O vacancy caused an increase of the barrier. This study provides theoretical support for understanding point defects in spinel LiMn2O4.
