H 2 O 2 is a green, environmentally friendly potential energy source. The photocatalytic reduction of molecular oxygen to synthesise H 2 O 2 is an eco-friendly strategy compared with the ...anthraquinone method and H 2 /O 2 direct synthesis. We proposed oxygen-enriched carbon nitride polymer (OCN) models, which were proven to more easily produce 1,4-endoperoxide species and have a high selectivity for molecular oxygen reduction to H 2 O 2 , rather than superoxide radicals, through theoretical calculations and experiments. The apparent quantum yield for H 2 O 2 production by OCNs reached 10.2% at 420 nm under an O 2 atmosphere, which was 3.5 times higher than that of g-C 3 N 4 and the activity did not decay over 20 h. OCN has a better oxygen reducibility and electron–hole separation efficiency than g-C 3 N 4 and is more prone to 2-electron reduction in the ORR. This work promotes understanding of the mechanism of photocatalytic oxygen reduction and provides a new idea for the design and synthesis of new materials for the preparation of H 2 O 2 .
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•A novel micro-electrolysis reactor was developed.•The shortcoming of conventional micro-electrolysis reactor can be thoroughly eliminated.•High performance of ICE reactor was ...achieved.•The BI of dyes wastewater can be 23times improved.
A novel micro-electrolysis reactor bringing iron-carbon filler to cycle flow was developed in this study, called as an internal circulation micro-electrolysis (ICE) reactor, which can overcome the disadvantage of conventional fixed bed (CFB) reactor. In order to investigate the performance of the ICE reactor, a practical dyes wastewater was selected as target wastewater. The removal efficiency of chemical oxygen demand (COD) and chroma of the CFB reactor with commercial hardening resistance iron-carbon filler (CRIF) are only 23% and 40%, respectively. However, for the ICE reactor with a common iron-carbon mixture (CIM), the removal efficiency of COD and chroma are 73% and 98.5%, respectively. The improvement efficiency of biodegradability index of dyes wastewater for the ICE reactor with the CIM is 23 times, which is about fourfold as much as that of the CFB reactor with CRIF. The ICE reactor with CIM can stably keep a high treatment performance for 60days continuous operation. However, the performance of CFB reactor with CIM decreases sharply. The results indicate that the ICE reactor has an excellent performance for the pretreatment of dyes wastewater, which should be due to the elimination of hardening, blocking and inactivation occurring in the CFB reactor with CIM by the circulation action.
CREG1 (cellular repressor of E1A-stimulated genes 1) is involved in tissue homeostasis and influences macroautophagy/autophagy to protect cardiovascular function. However, the physiological and ...pathological role of CREG1 in the skeletal muscle is not clear. Here, we established a skeletal muscle-specific creg1 knockout mouse model (creg1;Ckm-Cre) by crossing the Creg1-floxed mice (Creg1
fl/fl
) with a transgenic line expressing Cre recombinase under the muscle-specific Ckm (creatine kinase, muscle) promoter. In creg1;Ckm-Cre mice, the exercise time to exhaustion and running distance were significantly reduced compared to Creg1
fl/fl
mice at the age of 9 months. In addition, the administration of recombinant (re)CREG1 protein improved the motor function of 9-month-old creg1;Ckm-Cre mice. Moreover, electron microscopy images of 9-month-old creg1;Ckm-Cre mice showed that the mitochondrial quality and quantity were abnormal and associated with increased levels of PINK1 (PTEN induced putative kinase 1) and PRKN/PARKIN (parkin RBR E3 ubiquitin protein ligase) but reduced levels of the mitochondrial proteins PTGS2/COX2, COX4I1/COX4, and TOMM20. These results suggested that CREG1 deficiency accelerated the induction of mitophagy in the skeletal muscle. Mechanistically, gain-and loss-of-function mutations of Creg1 altered mitochondrial morphology and function, impairing mitophagy in C2C12 cells. Furthermore, HSPD1/HSP60 (heat shock protein 1) (401-573 aa) interacted with CREG1 (130-220 aa) to antagonize the degradation of CREG1 and was involved in the regulation of mitophagy. This was the first time to demonstrate that CREG1 localized to the mitochondria and played an important role in mitophagy modulation that determined skeletal muscle wasting during the growth process or disease conditions.
Abbreviations: CCCP: carbonyl cyanide m-chlorophenylhydrazone; CKM: creatine kinase, muscle; COX4I1/COX4: cytochrome c oxidase subunit 4I1; CREG1: cellular repressor of E1A-stimulated genes 1; DMEM: dulbecco's modified eagle medium; DNM1L/DRP1: dynamin 1-like; FCCP: carbonyl cyanide p-trifluoro-methoxy phenyl-hydrazone; HSPD1/HSP60: heat shock protein 1 (chaperonin); IP: immunoprecipitation; MAP1LC3B/LC3B: microtubule-associated protein 1 light chain 3 beta; MFF: mitochondrial fission factor; MFN2: mitofusin 2; MYH1/MHC-I: myosin, heavy polypeptide 1, skeletal muscle, adult; OCR: oxygen consumption rate; OPA1: OPA1, mitochondrial dynamin like GTPase; PINK1: PTEN induced putative kinase 1; PPARGC1A/PGC-1α: peroxisome proliferative activated receptor, gamma, coactivator 1 alpha; PRKN/PARKIN: parkin RBR E3 ubiquitin protein ligase; PTGS2/COX2: prostaglandin-endoperoxide synthase 2; RFP: red fluorescent protein; RT-qPCR: real-time quantitative PCR; SQSTM1/p62: sequestosome 1; TFAM: transcription factor A, mitochondrial; TOMM20: translocase of outer mitochondrial membrane 20; VDAC: voltage-dependent anion channel.
Abstract The dissolution of silicate glasses has implications in diverse fields ranging from the immobilization of radioactive waste to the development of sustainable alternatives to Portland cement. ...Here, we used ab initio molecular dynamics simulations biased with well-tempered metadynamics to study Si-O-T bridge dissociation in calcium aluminosilicate glasses, crucial for understanding their dissolution. In a departure from the conventional Michalske-Freiman model, our findings reveal a nucleophilic substitution reaction mechanism characterized by a short-lived, 5-fold coordinated Si intermediate or transition state, depending on the Si bridge coordination, with a near-trigonal bipyramidal geometry. We find that the reorganization required for reaching this state causes the activation energy barriers to be dependent on the Si bridge coordination, with Si Q 3 species serving as the rate-limiting step in the dissolution reaction. Our findings not only challenge long-standing theoretical models but also pave the way for more accurate and comprehensive frameworks for understanding the dissolution of silicate glasses in various applications.
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•The energy barrier of the rate-limiting step reduced from 16.0 kcal/mol to 14.3 kcal/mol.•The angle of nucleophile reaction is optimized from 141.3° to 166.9°.•Investigation of the ...small regulator in LWM-PTPase by the ONIOM(QM/MM) method.•The phosphate transfer reaction of LTP1 with and without adenine was investigated.
The mechanistic role of adenine, which assists the catalytic activity of low-molecular weight phosphatases, has been investigated using ONIOM calculations. Results confirm the dephosphorylation step being the rate-limiting step. In the absence and presence of adenine, the energy barriers of the rate-limiting step are 16.0 kcal/mol and 14.3 kcal/mol respectively, in agreement with experimental data. The formation of the favorable hydrogen bond contributes to the decreasing of barrier energy, resulting in the optimized attacking angle of the nucleophile. These results support the notion that adenine disfavors the formation of adverse hydrogen bond, which enables more effective hydrolyzation of phosphoenzyme intermediate.
AMPylation is a prevalent posttranslational modification that involves the addition of adenosine monophosphate (AMP) to proteins. Exactly how Huntingtin-associated yeast-interacting protein E (HYPE), ...as the first human protein, is involved in the transformation of the AMP moiety to its substrate target protein (the endoplasmic reticulum chaperone binding to immunoglobulin protein (BiP)) is still an open question. Additionally, a conserved glutamine plays a vital key role in the AMPylation reaction in most filamentation processes induced by the cAMP (Fic) protein. In the present work, the detailed catalytic AMPylation mechanisms in HYPE were determined based on the density functional theory (DFT) method. Molecular dynamics (MD) simulations were further used to investigate the exact role of the inhibitory glutamate. The metal center, Mg2+, in HYPE has been examined in various coordination configurations, including 4-coordrinated, 5-coordinated and 6-coordinated. DFT calculations revealed that the transformation of the AMP moiety of HYPE with BiP followed a sequential pathway. The model with a 4-coordinated metal center had a barrier of 14.7 kcal/mol, which was consistent with the experimental value and lower than the 38.7 kcal/mol barrier of the model with a 6-coordinated metal center and the 31.1 kcal/mol barrier of the model with a 5-coordinated metal center. Furthermore, DFT results indicated that Thr518 residue oxygen directly attacks the phosphorus, while the His363 residue acts as H-bond acceptor. At the same time, an MD study indicated that Glu234 played an inhibitory role in the α-inhibition helix by regulating the hydrogen bond interaction between Arg374 and the Pγ of the ATP molecule. The revealed sequential pathway and the inhibitory role of Glu234 in HYPE were inspirational for understanding the catalytic and inhibitory mechanisms of Fic-mediated AMP transfer, paving the way for further studies on the physiological role of Fic enzymes.
Owing to the ubiquity of wireless networks and the popularity of WiFi infrastructures, received signal strength (RSS)-based indoor localization systems have received much attention. The placement of ...access points (APs) significantly influences localization accuracy and network access. However, the indoor scenario and network access are not fully considered in previous AP placement optimization methods. This study proposes a practical scenario modeling-aided AP placement optimization method for improving localization accuracy and network access. In order to reduce the gap between simulation-based and field measurement-based AP placement optimization methods, we introduce an indoor scenario modeling and Gaussian process-based RSS prediction method. After that, the localization and network access metrics are implemented in the multiple objective particle swarm optimization (MOPSO) solution, Pareto front criterion and virtual repulsion force are applied to determine the optimal AP placement. Finally, field experiments demonstrate the effectiveness of the proposed indoor scenario modeling method and RSS prediction model. A thorough comparison confirms the localization and network access improvement attributed to the proposed anchor placement method.
Human cellular repressor of E1A-stimulated genes (CREG) is a secreted glycoprotein that regulates tissue and cell homeostasis and has been shown to antagonize heart fibrosis, which indicates a ...potential protective effect of CREG against cardiomyocyte chronic damage. However, little is known about the role of CREG in myocardial tissue acute injury, in this study, we aimed to investigate the role of CREG in myocardial ischemia/reperfusion (MI/R) injury and clarify the mechanism of action.
Wild-type Creg (Creg+/+), heterozygous Creg (Creg+/−) mice and mice pretreated with infusion of recombinant 0.3mg/kg·d CREG protein (reCreg+/+) were subjected to 30min of left ascending coronary ischemia and 24h of reperfusion. Evan's Blue-triphenyl- tetrazolium chloride (TTC) solution and echocardiography analysis were used to evaluate the effects of CREG on MI/R mice. The underlying mechanisms were further determined by cultured myocardial cells in vitro. Our findings revealed that the level of CREG protein in mouse hearts was significantly decreased after mice were subjected to MI/R. Moreover, Creg+/− mice had larger infarction size 2h after reperfusion and worse cardiac function 28days after MI/R injury compared to that in Creg+/+ mice. However, reCreg+/+ mice could maintain CREG at a high level even after MI/R injury, and mitigated infarction size and improved cardiac function significantly. In Creg+/− mice, myocardial autophagy was dysfunctional characterized by accumulation of LC3A and p62, while apoptotic cell number increase was detected by cleaved caspase-3 blotting and TUNEL staining. Conversely, decreased apoptosis and activated autophagy were detected in reCreg+/+ mice. Furthermore, chloroquine, a kind of autophagy blocker, was used to demonstrate recombinant CREG protected cardiomyocytes against apoptosis mediated by activating autophagy both in vivo and in vitro. Finally, we found CREG was involved into lysosomal protein transfer and improve cellular autophagy.
CREG protects heart against MI/R injury-induced cardiomyocytes apoptosis by activating lysosomal autophagy.
This article is part of a Special Issue entitled: Genetic and epigenetic control of heart failure - edited by Jun Ren and Megan Yingmei Zhang.
•CREG mitigates infarction and improves cardiac function induced by MI/R injury.•CREG plays an important role in anti-apoptosis of cardiomyocytes.•CREG activates lysosomal autophagy to protect heart from MI/R injury.
MiR-221 and miR-222 (miR-221/222), upregulated in gliomas, can regulate glioma cell cycle progression and apoptosis, respectively. However, the association of miR-221/222 with glioma cell invasion ...and survival remains unknown.
Invasion capability of miR-221/222 was detected by mutiple analyses, including diffusion tensor imaging (DTI), transwell, wound healing and nude mouse tumor xenograft model assay. Further, the target of miR-221/222 was determined by luciferase reporter, western blot and gene rescue assay. The association of miR-221/222 with outcome was examined in fifty glioma patients.
MiR-221/222 expression was significantly increased in high-grade gliomas compared with low-grade gliomas, and positively correlated with the degree of glioma infiltration. Over-expression of miR-221/222 increased cell invasion, whereas knockdown of miR-221/222 decreased cell invasion via modulating the levels of the target, TIMP3. Introduction of a TIMP3 cDNA lacking 3' UTR abrogated miR-221/222-induced cell invasion. In addition, knockdown of miR-221/222 increased TIMP3 expression and considerably inhibited tumor growth in a xenograft model. Finally, the increased level of miR-221/222 expression in high-grade gliomas confers poorer overall survival.
The present data indicate that miR-221 and miR-222 directly regulate cell invasion by targeting TIMP3 and act as prognostic factors for glioma patients.
As the scale and complexity have been increased in software systems, developers place more emphases on software engineering and system designs. Software architecture is evolved with update of ...softwares, and it plays a fundamental role in determining quality of software systems. Multifractal characteristics of software networks can reflect software quality. In this paper, we construct a software network from the dependencies between object classes, and gain a deep understanding of software through network analysis. To be specific, multifractal analysis of the software network is performed based on a modified box-covering algorithm that yields fewer boxes. We verify that software with different functions and dependencies is multifractal. Further, different versions of the software are compared to discover the evolution of the software architecture. The results show that the singularity of class dependencies decreases as the software is updated. This trend leads to a more specific division of functions between software modules. One of the visible advantages of our work is that it allows the characterization of software structures at the code level. The methodology and results of this paper provide new insights into the evaluation and design of large-scale software systems.
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