Fossils document evolutionary changes of jaw joint to mammalian middle ear.

The dual jaw joint of Morganucodon1,2 consists of the dentary-squamosal joint laterally and the articular-quadrate one medially. The articular-quadrate joint and its associated post-dentary bones constitute the precursor of the mammalian middle ear. Fossils documenting the transition from such a precursor to the mammalian middle ear are poor, resulting in inconsistent interpretations of this hallmark apparatus in the earliest stage of mammaliaform evolution1-5. Here we report mandibular middle ears from two Jurassic mammaliaforms: a new morganucodontan-like species and a pseudotribosphenic shuotheriid species6. The morganucodontan-like species shows many previously unknown post-dentary bone morphologies1,2 and exhibits features that suggest a loss of load-bearing function in its articular-quadrate joint. The middle ear of the shuotheriid approaches the mammalian condition in that it has features that are suitable for an exclusively auditory function, although the post-dentary bones are still attached to the dentary. With size reduction of the jaw-joint bones, the quadrate shifts medially at different degrees in relation to the articular in the two mammaliaforms. These changes provide evidence of a gradual loss of load-bearing function in the articular-quadrate jaw joint-a prerequisite for the detachment of the post-dentary bones from the dentary7-12 and the eventual breakdown of the Meckel's cartilage13-15 during the evolution of mammaliaforms.

Acute Helicobacter pylori infection prevalence and association with metabolic abnormality in general Chinese population: A retrospective study.

Helicobacter pylori (H pylori) infection was common worldwide and previous researches on the correlation between H pylori infection and metabolic abnormality provided inconsistent conclusions. We assessed acute H pylori infection prevalence and the relationship with metabolic abnormality in general Chinese population. Participants attending for the physical examination underwent a carbon-13 urea breath test. For individual, the following data were collected: age, gender, body mass index (BMI), systolic blood pressure, diastolic blood pressure, total protein, albumin, globulin (GLB), total bilirubin, direct bilirubin (DBIL), indirect bilirubin, alanine transaminase, glutamyl transpeptidase, alkaline phosphatase, cholesterol, triglyceride, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, urea nitrogen, creatinine, uric acid, fasting plasma glucose (FPG), and homocysteine. A total of 29,154 participants were enrolled. The prevalence of acute H pylori infection was 29.79% (8684/29,154). Spearson correlation analysis showed that gender, BMI, ALB, GLB, total bilirubin, DBIL, indirect bilirubin, and FPG were closely related to H pylori infection. Multinomial logistic regressions analysis with stepwise subset selection further identified gender, BMI, ALB, GLB, DBIL, and FPG as independent risk factors for acute H pylori infection. Our results indicated that acute H pylori infection might has a significant impact on metabolic abnormalities, which should be further confirmed.

Effects of Fe(II) and humic acid on U(VI) mobilization onto oxidized carbon nanofibers derived from the pyrolysis of bacterial cellulose.

The effects of Fe(II) and humic acid on U(VI) immobilization onto oxidized carbon nanofibers (Ox-CNFs, pyrolysis of bacterial cellulose) were investigated by batch, spectroscopic and modeling techniques, with results suggesting that, Ox-CNFs exhibited fast adsorption rate (adsorption equilibrium within 3 h), high adsorption performance (maximum adsorption capacity of 208.4 mg/g), good recyclability (no notable change after five regenerations) in the presence of Fe(II) towards U(VI) from aqueous solutions (e.g., 40 % reduction and 10 % adsorption at pH 8.0), which was attributed to the various oxygen-containing functional groups, excellent chemical stability, large specific surface area and high redox effect. U(VI) adsorption increased with increasing pH from 2.0 to 5.0, then high-level plateau and remarkable decrease were observed at 5.0-6.0 and at pH > 6.0, respectively. According to FT-IR and XPS analysis, a negative correlation between U(VI) reduction and organic in the presence of Fe(II) implied that U(VI) reduction was driven by Fe(II) while inhibited by humic acid. The interaction mechanism of U(VI) on Ox-CNFs was demonstrated to be adsorption and ion exchange at low pH and reduction at high pH according to XPS and surface complexation modeling. These findings filled the knowledge gaps pertaining to the effect of Fe(II) on the transformation and fate of U(VI) in the actual environment. This carbon material with distinctive performance and unique topology offers a potential platform for actual application in environmental remediation.

Radiological characteristics predicting early poor drug response in patients with hemifacial spasm.

OBJECTIVES: Patients with hemifacial spasm (HFS) often resort to botulinum toxin injections or microvascular decompression surgery when medication exhibits limited effectiveness. This study aimed to identify MRI and demographic factors associated with poor drug response at an early stage in patients with HFS. METHODS: We retrospectively included patients with HFS who underwent pre-therapeutic MRI examination. The presence, location, severity, and the offending vessels of neurovascular compression were blindly evaluated using MRI. Drug responses and clinical data were obtained from the medical notes or phone follow-ups. Logistic regression analysis was performed to identify potential factors. RESULTS: A total of 116 patients were included, with an average age at the time of first examination of 50.4 years and a median duration of onset of 18 months. Forty-nine (42.2%) patients reported no symptom relief. Thirty-seven (31.9%) patients reported poor symptom relief. Twenty-two (19.0%) patients reported partial symptom relief. Eight (6.9%) patients achieved complete symptom relief. The factors that were statistically significant associated with poor drug responses were contact in the attach segment of the facial nerve and aged 70 and above, with an odds ratio of 7.772 (p = 0.002) and 0.160 (p = 0.028), respectively. CONCLUSIONS: This study revealed that mild compression in the attach segment of the facial nerve in pre-therapeutic MRI increases the risk of poor drug responses in patients with HFS, while patients aged 70 and above showed a decreased risk. These findings may assist clinician to choose optimal treatment at an early stage.

Evaluating magnetic resonance imaging characteristics and risk factors for hemifacial spasm.

PURPOSE: The specific neurovascular compression (NVC) event responsible for the symptomatic manifestation of hemifacial spasm (HFS) remains difficult to assess accurately using magnetic resonance imaging (MRI). We aim to evaluate the MRI characteristics of HFS. METHOD: We retrospectively included patients with HFS and divided them into a test group (n = 186) and a validation group (n = 28). The presence, severity, and offending vessel type of NVC in each portion, and the orientation of the offending vessel around the facial nerve, were recorded. Conditional logistic regression analyses were performed to evaluate correlations using test group. The validation group was used to verify whether our findings improved diagnostic performance. RESULTS: Deformity in the proximal cisternal segment was significantly correlated with HFS occurrence (odds ratio [OR]: 256.58, p = .002), whereas contact was not (p = .233). Both contact and deformity in the root detachment point (OR: 19.98 and 37.22, p < .001 and p = .013, respectively) or attached segment (OR: 4.99 and 252.52, p = .001 and p < .001, respectively) were significantly correlated with HFS occurrence. Our findings improved specificity, positive predictive value, and accuracy of diagnosis than conventional diagnostic methods. The vertebral artery predominantly compress the facial nerve in the inferior-anterior position, the anterior inferior cerebellar artery predominantly in the inferior position, the posterior inferior cerebellar artery predominantly in the inferior position, vein predominantly in the posterior-superior position. CONCLUSIONS: This study further demonstrates that within the susceptible portion of facial nerve, different portions of the nerve respond differently to NVC. Each offending vessel has its own preferred conflict orientation. Our study offers reference for neurosurgeons in diagnosis and treatment.

Operando Mobile Catalysis for Reverse Water Gas Shift Reaction.

Metal atoms on the support serve as active sites for many heterogeneous catalysts. However, the active metal sites on the support are conventionally described as static, and the intermediates adsorbed on the support far away from the active metal sites cannot be transformed. Herein, we report the first example of operando mobile catalysis to promote catalytic efficiency by enhancing the collision probability between active sites and reactants or reaction intermediates. Specifically, ligand-coordinated Pt single atoms (isolated MeCpPt- species) are bonded on CeO2 and transformed into mobile MeCpPt(H)CO complexes during the reverse water gas shift reaction for operando mobile catalysis. This strategy enables the conversion of inert carbonate intermediates on the CeO2 support. A turnover frequency (TOF) of 6358 mol CO2 molPt -1 ⋅ h-1 and 99 % CO selectivity at 300 °C is obtained for reverse water gas shift reaction, dramatically higher than those of Pt catalysts reported in the literature. Operando mobile catalysis presents a promising strategy for designing high-efficiency heterogeneous catalysts for various chemical reactions and applications.

NK-derived exosome miR-1249-3p inhibits Mycobacterium tuberculosis survival in macrophages by targeting SKOR1.

Murine Natural Killer cells were cultivated in vitro to isolate NK-derived exosomes. Subsequent quantification via qPCR confirmed enrichment of miR-1249-3p. Ana-1 murine macrophages were cultured in vitro and subsequently inoculated with Mycobacterium tuberculosis (MTB) strain H37Rv. NK-exo and NK-exo miR-1249-3p were separately applied to the infection model, followed by immunological assays conducted post-48-hour co-culture. Western blot analyses corroborated that NK-exo exhibited exosomal marker proteins Granzyme A (GzmA), Granzyme B (GzmB), and Perforin (PFN), alongside a notable enrichment of miR-1249-3p. Functionally, NK-exo augmented the expression levels of Caspase-9,-8, and -3, as well as PARP, while attenuating the expression of NLRP3, ASC, and Cleaved-Caspase-1. Furthermore, qPCR demonstrated an up-regulation of Caspase-9, -8, and -3, along with pro-apoptotic factors Bax and Bid, and a concomitant down-regulation of the anti-apoptotic factor Bcl-2. The expression levels of inflammatory markers ASC, NLRP3, Cleaved-Caspase-1, and IL-1ß were concomitantly decreased. ELISA findings indicated diminished levels of TNF-α and ROS secretion. NK-exo miR-1249-3p specifically targeted and attenuated the expression of SKOR-1, engendering up-regulation of apoptosis-associated proteins and down-regulation of inflammation-related proteins, consequently affecting cellular fate.Our empirical evidence substantiates that NK-exo induces macrophage apoptosis, thereby mitigating MTB survival. Furthermore, NK-exo miR-1249-3p directly targets and inhibits SKOR-1 expression, leading to macrophage apoptosis and consequently hampering the proliferation of MTB. The data implicate the potential therapeutic relevance of NK-exo and miR-1249-3p in managing drug-resistant tuberculosis.

MicroRNA-322 Attenuates Cartilage Matrix Degradation in Osteoarthritis via Direct Suppression of TRAF3.

OBJECTIVE: Osteoarthritis (OA) is a degenerative joint disease. A growing number of studies have shown that microRNAs (miRNAs) play an important role in the pathogenesis of OA. However, the specific function of miR-322 in OA is unknown. This study was aimed to explore the ability of miR-322 in the cartilage matrix degradation and the mechanism in OA. METHODS: Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was performed to detect miR-322 expression in cartilage and OA-associated gene expression in chondrocytes treated with miR-322 mimics/inhibitors or interleukin (IL)-1ß, respectively. The targets of miR-322 were analyzed using software and the luciferase reporter experiment. In vivo, intra-articular injection of miR-322 mimics was administered at the knee of DMM mice. After 12 weeks, the knee joints of mice were collected for histological analysis. RESULTS: The expression of miR-322 was decreased in knee cartilage of DMM mice and was significantly reduced by IL-1ß. miR-322 mimics inhibited IL-1ß-induced extracellular matrix degradation, as evidenced by higher expression of Col2α1 and Aggrecan, and lower expression of Adamts5, MMP3, and MMP13. In contrast, miR-322 inhibitor promoted extracellular matrix degradation of chondrocytes. TRAF3 was the predicted target of miR-322 from databases. Luciferase reporter assay verified the targeting relationship between miR-322 and TRAF3. The effect of miR-322 on extracellular matrix degradation was partially reversed by overexpression of TRAF3. In addition, H&E and Safranin-O fast green staining assays in OA mouse models showed that miR-322 mimics attenuated the progression of OA in vivo. CONCLUSIONS: miR-322 suppressed chondrocytes matrix degradation and alleviated OA cartilage injury via inhibition of the TRAF3.

Directly and ultrasensitivity detecting SARS-CoV-2 spike protein in pharyngeal swab solution by using SERS-based biosensor.

The global pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a great disaster to the economy and human society. Nowadays, SARS-CoV-2 is fading away from people's memory but it still exists around us. PCR plays an important role in detecting SARS-CoV-2 but it requires a long detecting time, equipped laboratory, and professional operators. In comparison with polymerase chain reaction (PCR), surface-enhanced Raman scattering (SERS) is a promising method for detecting SARS-CoV-2 due to its fast, easily operated, and high-sensitivity properties. In this study, the monolayer Ag nanoparticles (MAgNPs) covered with single-layer graphene (SLG) are applied as a SERS substrate. The angiotensin converting enzyme 2 (ACE2) is selected as a bio-probes that can specifically bind to the SARS-CoV-2 S protein. The SERS-based biosensor is formed by ACE2 functionalized SLG/MAgNPs and the LODs of detecting SARS-CoV-2 S protein in phosphate-buffered saline (PBS) and in pharyngeal swabs solution (PSS) are 0.1 fg mL-1 and 10 fg mL-1, respectively. This biosensor provides a way of directly detecting SARS-CoV-2 S protein with high sensitivity and specificity. It illustrates a practical potential in the rapid detection of the SARS-CoV-2 virus.

Halide solid-state electrolytes for all-solid-state batteries: structural design, synthesis, environmental stability, interface optimization and challenges.

Since the huge breakthrough in 2018, research on halide solid-state electrolytes (SSEs) has set off a new craze. In comparison with oxide and sulfide SSEs, halide SSEs have more balanced properties in various aspects, including ionic conductivity, electrochemical stability window, and moisture resistance. Herein, the overall knowledge and deep understanding of halide SSEs and their practical applications in all-solid-state batteries (ASSBs) are introduced. Firstly, the principle of screening halide SSE components is proposed. Among F, Cl, Br and I anions, the Cl anion is excellent owing to its suitable ionic conductivity and electrochemical stability window. The Sc, Y, and lanthanide elements are also more compatible with Cl anions in terms of electronegativity. Secondly, the structural design theory of halide SSEs with high ionic conductivity and the mechanism of Li ion migration are described. A monoclinic structure is more conducive to Li ion migration, compared with trigonal and orthorhombic structures. Additionally, substitution strategies for halide SSEs are discussed, mainly including dual-halogen, isovalent cation substitution, and aliovalent cation substitution. Furthermore, the mechanism of moisture resistance and synthesis method of halide SSEs are analyzed. Compared with the solid-state reaction and mechanochemistry method, wet chemical synthesis is more likely to achieve scale-up production of halide SSEs. Finally, the application prospects and challenges of halide SSEs in ASSBs are outlined.

Bifunctional Strategy toward Constructing Perovskite/Upconversion Lab-on-Paper Photoelectrochemical Device for Sensitive Detection of Malathion.

Bifunctional nanocrystals which combine two kinds of materials into single nanoparticles hold great promise in photoelectrochemical (PEC) analysis, particularly for nanocrystals based on perovskite quantum dots (QDs) which generally exhibit excellent photoelectric activity yet poor stability and upconversion nanoparticles (UCNP) that normally suffer from negligible photoelectric activity. Therefore, to achieve good performance of the PEC bioassay platform, it is valuable to combine perovskite QDs with UCNP encapsulation and promote their advantages to form hybrid nanocrystals that are stable, NIR excitable, and photoelectric. Herein, the core-shell configuration of perovskite/upconversion CsPbBr2I@NaYF4:Yb,Tm (CPBI@UCNP) nanocrystals coupled with a NiMn-layered double hydroxide (NiMn-LDH)/CdS heterojunction to form a cascade sensitization structure was proposed to construct the lab-on-paper PEC device for ultrasensitive detection of malathion pesticides. Concretely, the bifunctional CPBI@UCNP nanocrystals that encapsulated CPBI QDs into UCNPs were employed as a nanoscale light source and sensitizer in the lab-on-paper system, which not only prevented the degradation of perovskite QDs but also overcame the negligible photoelectric performance of pristine UCNPs with the cooperation of photoactive CPBI QDs. The synergistic quenching effect, including fluorescence energy resonance transfer (FRET) and photoinduced electron transfer (PET), was created to realize enhanced PEC signal readout. Benefiting from the dynamic cascade sensitization structure of CPBI@UCNP/NiMn-LDH/CdS and synergistic quenching effect of FRET/PET, the ultrasensitive detection of malathion was achieved with high selectivity, reproducibility, and stability, which provided guidelines to employ perovskite/upconversion nanomaterials for lab-on-paper PEC analysis.

Is there a bidirectional relationship between workplace bullying and the risk of sickness absence? Systematic review and meta-analysis of prospective studies.

Exposure to workplace bullying increases the risk of sickness absence. However, the extent and direction of this relationship for different follow-up lengths are not well established. To provide evidence regarding the direction and extent of the relationship between workplace bullying and different durations of sickness absence. We searched nine databases from their inception to 29 November 2022. Multiple independent observers screened the literature, extracted the data and used the Risk Of Bias In Non-randomised Studies of Exposure to assess the methodological quality. The overall effect sizes of odds ratio, relative risk, hazard ratio and 95% confidence intervals were calculated. Our meta-analysis demonstrated a 26% increased risk of sick leave among workers exposed to workplace bullying for all follow-up lengths (95% CI 1.18 to 1.35), even after adjusting for confounding factors. Moreover, we found a significant association between long-term sickness absence and a higher likelihood of subsequent exposure to workplace bullying, with a pooled OR of 1.63 (95% CI 1.21 to 2.04). Our study established a bidirectional relationship between workplace bullying and long-term sickness absence, highlighting that it increases the risk of sickness absence at different follow-up lengths among employees who have been bullied. Hence, organisations should be mindful of workers who resume work after prolonged absences due to illness and adopt appropriate management strategies to prevent workplace bullying.

Nano-biosensor for SARS-CoV-2/COVID-19 detection: methods, mechanism and interface design.

The epidemic of coronavirus disease 2019 (COVID-19) was a huge disaster to human society. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which led to COVID-19, has resulted in a large number of deaths. Even though the reverse transcription-polymerase chain reaction (RT-PCR) is the most efficient method for the detection of SARS-CoV-2, the disadvantages (such as long detection time, professional operators, expensive instruments, and laboratory equipment) limit its application. In this review, the different kinds of nano-biosensors based on surface-enhanced Raman scattering (SERS), surface plasmon resonance (SPR), field-effect transistor (FET), fluorescence methods, and electrochemical methods are summarized, starting with a concise description of their sensing mechanism. The different bioprobes (such as ACE2, S protein-antibody, IgG antibody, IgM antibody, and SARS-CoV-2 DNA probes) with different bio-principles are introduced. The key structural components of the biosensors are briefly introduced to give readers an understanding of the principles behind the testing methods. In particular, SARS-CoV-2-related RNA mutation detection and its challenges are also briefly described. We hope that this review will encourage readers with different research backgrounds to design SARS-CoV-2 nano-biosensors with high selectivity and sensitivity.

Monodisperse MoS2/Graphite Composite Anode Materials for Advanced Lithium Ion Batteries.

Traditional graphite anode material typically shows a low theoretical capacity and easy lithium decomposition. Molybdenum disulfide is one of the promising anode materials for advanced lithium-ion batteries, which possess low cost, unique two-dimensional layered structure, and high theoretical capacity. However, the low reversible capacity and the cycling-capacity retention rate induced by its poor conductivity and volume expansion during cycling blocks further application. In this paper, a collaborative control strategy of monodisperse MoS2/graphite composites was utilized and studied in detail. MoS2/graphite nanocomposites with different ratios (MoS2:graphite = 20%:80%, 40%:60%, 60%:40%, and 80%:20%) were prepared by mechanical ball-milling and low-temperature annealing. The graphite sheets were uniformly dispersed between the MoS2 sheets by the ball-milling process, which effectively reduced the agglomeration of MoS2 and simultaneously improved the electrical conductivity of the composite. It was found that the capacity of MoS2/graphite composites kept increasing along with the increasing percentage of MoS2 and possessed the highest initial discharge capacity (832.70 mAh/g) when MoS2:graphite = 80%:20%. This facile strategy is easy to implement, is low-cost, and is cosmically produced, which is suitable for the development and manufacture of advance lithium-ion batteries.

Ready-to-use interactive dual-readout differential lateral flow biosensor for two genotypes of human papillomavirus.

Ready-to-use in vitro diagnosis of multiple genotypes is vital for the prevention and treatment of cervical cancer. Herein, a paper-film-based interactive dual readout differential lateral flow biosensor is proposed to simultaneously assay two high-risk types of human papillomavirus (HPV) within the body-fluid. The CuCo2S4/ZnIn2S4 heterostructure is fabricated on the paper-film compound chip with high thermostability, and surface sulfur vacancy is introduced by mild annealing treatment to endow unexceptionable photoexcitation activity, such structure can be served as an initial energy harvester and converter. With the assistance of differential channels, the dual-target-propelled self-assembly of annular DNA and the cleavage activity of CRISPR-Cas12a are stepwise activated by sequential solution transfer. Accordingly, the input and release of polydopamine-coated gold nanoparticles with photothermal/photoelectric characteristic were implemented. The fabricated biosensor not only realized intelligent thermal-response without large instruments, but also actuated dynamic interfacial charge separation and transfer kinetics to further transmit photoelectric-signal, resulting in desirable interactive dual-signal with low limit-of-detection (0.21 pM for HPV-18 and 42.92 pM for HPV-16). Thanks to the sophisticated design of differential lateral flow paper-film compound chip and interactive dual-signal amplification strategy, sensitive detection of two HPV genotypes is realized, which provides a promising candidate for home medical intelligent diagnosis.

Analysis of differentially expressed proteins after EHP-infection and characterization of caspase 3 protein in the whiteleg shrimp (Litopenaeus vannamei).

Whiteleg shrimp (Litopenaeus vannamei) is the most important species of shrimp farmed worldwide in terms of its economic value. Enterocytozoon hepatopenaei (EHP) infects the hepatopancreas, resulting in the hepatopancreatic microsporidiosis (HPM) of the host, which causes slow growth of the shrimp and poses a threat to the farming industry. In this study, differentially expressed proteins (DEPs) between EHP-infected and uninfected shrimp were investigated through proteomics sequencing. A total of 9908 peptides and 2092 proteins were identified. A total of 69 DEPs were identified in the hepatopancreas (HP), of which, 28 were upregulated and 41 were downregulated. Our results showed that the differences among the level of multiple proteins involved in the apoptosis were significant after the EHP infection, which indicated that the apoptosis pathway was activated in whiteleg shrimp. In addition, expression leve of caspase 3 gene were identified related to the EHP infection. Furthermore, predictions of spatial structure, analysis of phylogeny and chromosome-level linearity of the caspase 3 protein were performed as well. In conclusion, a relatively complete proteomic data set of hepatopancreas tissues in whiteleg shrimp were established in this study. Findings about genes involved in the apoptosis here will provide a further understanding of the molecular mechanism of EHP infection in the internal immunity of whiteleg shrimp.

Selection of candidate genes for differences in fat metabolism between cattle subcutaneous and perirenal adipose tissue based on RNA-seq.

The site of fat deposition plays an important role in meat quality and body health. Biologically, the perirenal visceral fat (PF) and back subcutaneous fat (BF) are distinct. Angus and Simmental cattle (Bos taurus) were used as models. HE staining, triglyceride assay kit and RNA-seq were used to analyze the differences in tissue morphology and lipid accumulation, co-genes, and differentially expressed genes (DEGs) between the two tissues. According to the findings, BF has a smaller cell area and greater lipid deposition ability than PF. RNA-seq generated approximately 10.99 Gb of data in each library, and 23,472 genes were identified. The genes FABP4, ADIRF, and SCD that are related to adipose deposition were highly expressed in four tissues. There were 1678 DEGs and 1955 DEGs between BF and PF in Angus and Simmental cattle respectively. Gene Ontology function analysis identified several DEGs involved in metabolism. KEGG pathway analysis showed that four pathways related to fat metabolism were enriched. In the BF, seven genes (COL1A1, COL1A2, COL3A1, COL2A1, RXRA, C1QTNF7, and MOGAT2) were up-regulated. Five genes (ADRB3, ABHD5, CPT1B, CD36, LPIN1) were down-regulated. This study identified candidate genes that led to differences in fat metabolism, which could be useful in cattle breeding.

Pt-Based Oxygen Reduction Reaction Catalysts in Proton Exchange Membrane Fuel Cells: Controllable Preparation and Structural Design of Catalytic Layer.

Proton exchange membrane fuel cells (PEMFCs) have attracted extensive attention because of their high efficiency, environmental friendliness, and lack of noise pollution. However, PEMFCs still face many difficulties in practical application, such as insufficient power density, high cost, and poor durability. The main reason for these difficulties is the slow oxygen reduction reaction (ORR) on the cathode due to the insufficient stability and catalytic activity of the catalyst. Therefore, it is very important to develop advanced platinum (Pt)-based catalysts to realize low Pt loads and long-term operation of membrane electrode assembly (MEA) modules to improve the performance of PEMFC. At present, the research on PEMFC has mainly been focused on two areas: Pt-based catalysts and the structural design of catalytic layers. This review focused on the latest research progress of the controllable preparation of Pt-based ORR catalysts and structural design of catalytic layers in PEMFC. Firstly, the design principle of advanced Pt-based catalysts was introduced. Secondly, the controllable preparation of catalyst structure, morphology, composition and support, and their influence on catalytic activity of ORR and overall performance of PEMFC, were discussed. Thirdly, the effects of optimizing the structure of the catalytic layer (CL) on the performance of MEA were analyzed. Finally, the challenges and prospects of Pt-based catalysts and catalytic layer design were discussed.

Numerical simulation and parameter optimization of earth auger in hilly area using EDEM software.

Digging in hilly regions is an important measure to promote afforestation on difficult sites. In view of the working conditions to build fish-scale pit on slope, the auger mechanism of soil lifting and throwing was investigated in this study. This study utilized EDEM software to establish the operation model of the earth auger and conduct DEM (Discrete Element Method) virtual simulation experiments. A quadratic rotating orthogonal center combination test was implemented by setting the efficiency of conveying-soil (Y1) and the distance of throwing-soil (Y2) as the evaluation indices. Variance analysis and response surface optimization were performed on the virtual experimental data. The results indicated that the weight of the factors affecting the Y1 and Y2, were feeding speed > helix angle > rotating speed > slope angle, and slope auger > rotating speed > feeding speed > helix angle. The optimal parameter combination of each influencing factor was obtained. Among them, when the slope preparation was required, the optimal operating parameter combination of the auger was: Slope of 26.467°, Helix angle of 21.567°, Feeding speed of 0.1 m/s, Rotating speed of 67.408 r/min. This research provides theoretical references for the design optimization of the earth auger in hilly regions.