RESUMO
BACKGROUND: Artesunate (ART) has the potential to modulate the nuclear factor kappa B (NF-κB) and Notch1/Hes1 signaling pathways, which play crucial roles in the pathogenesis of osteoporosis. This study aims to explore whether ART participates in the progression of osteoporosis by regulating these signaling pathways. METHODS: In the in vitro experiments, we treated bone marrow mesenchymal stem cells (BMSCs) with different concentrations of ART (0, 3, 6, 12 µM) and evaluated osteogenic differentiation using alkaline phosphatase staining (ALP) and alizarin red S staining (ARS) staining. The expression levels of osteocalcin (OCN), RUNT-related transcription factor 2 (RUNX2), osteoprotegerin (OPG), and receptor activator of the nuclear factor kappa ligand (RANKL) were detected by real-time quantitative PCR (RT-qPCR). The effects of ART on NF-κB p65 and Notch1 protein expression were analyzed by Western blot (WB) and immunofluorescence (IF). In the in vivo experiments, a postmenopausal osteoporosis rat model was established via ovariectomy. Bone tissue pathological injury was evaluated using hematoxylin eosin (HE) staining. Serum ALP levels were measured using a kit, bone density was determined by dual-energy X-ray absorptiometry, and serum levels of bone gla protein (BGP), OPG, RANKL, tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6), and IL-1ß were measured by enzyme-linked immunosorbent assay (ELISA). Additionally, the expression of NF-κB p65 and Notch1 in tissues was assessed by immunohistochemistry. RESULTS: In vitro experiments revealed that compared to the control group, ART dose-dependently promoted BMSCs proliferation and enhanced their osteogenic differentiation capability. The expression of OCN, RUNX2, and OPG significantly increased in the ART-treated group, while RANKL expression decreased significantly (p < 0.05). ART significantly inhibited the expression of NF-κB p65 and Notch1/Hes1 signaling pathway proteins (p < 0.05). Compared to ART treatment alone, combined treatment with ART and phorbol myristate acetate (PMA) or valproic acid (VPA) resulted in increased expression of NF-κB p65 and Notch1 proteins and decreased osteogenic differentiation capability (p < 0.05). In vivo experiments showed that in rats treated with ART, bone damage was significantly reduced, bone density and mineral content were restored considerably, and the expression of inflammatory factors (TNF-α, IL-6, IL-1ß) decreased significantly (p < 0.05). Additionally, ART treatment significantly reduced the expression of NF-κB p65 and Notch1 proteins, increased OPG expression, and decreased BGP and RANKL levels (p < 0.05). CONCLUSION: In summary, ART facilitates the osteogenic differentiation of BMSCs by inhibiting the NF-κB and Notch1/Hes1 signaling pathways, thereby exerting significant protective effects against osteoporosis.
Assuntos
Artesunato , NF-kappa B , Osteoporose , Ovariectomia , Ratos Sprague-Dawley , Receptor Notch1 , Transdução de Sinais , Animais , Artesunato/farmacologia , Artesunato/uso terapêutico , Feminino , Transdução de Sinais/efeitos dos fármacos , Receptor Notch1/metabolismo , NF-kappa B/metabolismo , Osteoporose/metabolismo , Osteoporose/tratamento farmacológico , Osteoporose/etiologia , Ratos , Osteogênese/efeitos dos fármacos , Artemisininas/farmacologia , Artemisininas/uso terapêutico , Células-Tronco Mesenquimais/metabolismo , Células-Tronco Mesenquimais/efeitos dos fármacos , Inflamação/metabolismo , Diferenciação Celular/efeitos dos fármacos , Fatores de Transcrição HES-1RESUMO
The pursuit of pharmacological interventions in aging aims focuses on maximizing safety and efficacy, prompting an exploration of natural products endowed with inherent medicinal properties. Subsequently, this work establishes a unique library of plant extracts sourced from Yunnan Province, China. Screening of this herbal library herein revealed that Salsola collina (JM10001) notably enhances both lifespan and healthspan in C. elegans. Further analysis via network pharmacology indicates that the p53 signaling pathway plays a crucial role in mediating the anti-aging effects of JM10001. Additionally, this work identifies that a composition, designated as JM10101 and comprising three chemical constituents of JM10001, preserves the original lifespan-extending activity in C. elegans. Both JM10001 and JM10101 mitigate aging symptoms in senescence-accelerated mice treated with doxorubicin and in naturally aged mice. Notably, JM10101 exhibits a more sophisticated senomorphlytic role encompassing both senomorphic and senolytic functions than JM10001 in the modulation of senescent cells, offering a promising strategy for the discovery of combination drugs in the rational development of anti-aging therapies.
RESUMO
As the sole carbonaceous renewable energy source, biomass is distinguished by its abundant yield, widespread distribution, and carbon neutrality. It is integral to the achievement of zero and negative carbon production via conventional carbonaceous pellet technology. This study introduces a cradle-to-gate life cycle assessment methodology for biomass preparation in carbonaceous pellets. We prepare high-quality biochar through a process combining hydrothermal carbonization and pyrolytic carbonization. Biomass high molecular weight extracts are obtained via organic pyrolytic extraction, while biomass high-temperature binders result from the modification and treatment of biochar. Biomass carbonaceous pellets are then formed using hot press technology. The ReCiPe model facilitates a comprehensive life cycle assessment of biomass carbonaceous pellets used in blast furnace production. The study leverages two comprehensive evaluation indicators - renewability, and environmental performance - to enhance the environmental performance of the process system and to maximize energy-saving and emission reduction potential.
RESUMO
OBJECTIVE: Tumors are highly heterogeneous, and within their parenchyma, a small population of tumor-stem cells possessing differentiation potential, high oncogenicity, and self-renewal capabilities exists. These cells are pivotal in mediating tumor development, chemotherapy resistance, and recurrence. Ovarian cancer shares characteristics with tumor stem cells, making it imperative to investigate molecular markers associated with these cells. METHODS: Stem cell-related genes were collected, and molecular subtypes were established based on gene expression profiles from The Cancer Genome Atlas using the R package tool "ConsensusClusterPlus." Multi-gene prognostic markers were identified using LASSO regression analysis. Gene set enrichment analysis was employed to gain insights into the potential molecular mechanisms of these identified markers. The robustness of these prognostic markers was analyzed across different cohorts, and their clinical independence was determined through multivariate Cox analysis. A nomogram was constructed to assess the model's clinical applicability. Immunohistochemistry was performed to validate the expression of hub genes. RESULTS: Utilizing 49 tumor stem cell-related genes associated with prognosis, 362 ovarian cancer samples were divided into two distinct clusters, revealing significant prognostic disparities. A seven-gene signature (GALP, CACNA1C, COL16A1, PENK, C4BPA, PSMA2, and CXCL9), identified through LASSO regression, exhibited stability and robustness across various platforms. Multivariate Cox regression analysis confirmed the signature's independence in predicting survival in patients with ovarian cancer. Furthermore, a nomogram combining the gene signature demonstrated strong predictive abilities. Immunohistochemistry results indicated significantly elevated GALP, CACNA1C, COL16A1, PENK, C4BPA, PSMA2, and CXCL9 expression in cancer tissues. CONCLUSION: The seven-gene signature holds promise as a valuable tool for decision-making and prognosis prediction in patients with ovarian cancer.
Assuntos
Neoplasias Ovarianas , Humanos , Feminino , Neoplasias Ovarianas/genética , Prognóstico , Nomogramas , Células-Tronco NeoplásicasRESUMO
The rising prevalence of diabetes has led to an increased focus on real-time glucose monitoring. Wearable glucose sensor patches allow noninvasive, real-time monitoring, reducing patient discomfort compared to invasive sensors. However, most existing glucose sensor patches rely on complex and contaminating metal vapor deposition technologies, which pose limitations in practical production. In this study, we propose a novel approach for preparing graphite/multiwall carbon nanotubes (MWCNT)/reduced graphene oxide (rGO) using a high-viscosity ink, which can be easily obtained through simple mechanical stirring. To create intricate patterns and enable printing on curved substrates, we employed a 3D printer equipped with an infrared laser ranging system. The ink served as a working electrode, and we developed a three-electrode system patch with a concentric circle structure. Subsequently, the working electrode underwent enzymatic modification with glucose dehydrogenase with flavin adenine dinucleotide (GDH-FAD) using a polymer embedding method. The resulting wearable glucose sensor exhibited a sensitivity of 2.42 µA mM-1 and a linear detection range of 1-12 mM. In addition, the glucose sensor has excellent anti-interference capability and demonstrates good repeatability in simulated real human wear scenarios, which meets the requirements for accurate human detection. These findings provide valuable insights into the development of human health monitoring technologies.
Assuntos
Grafite , Nanotubos de Carbono , Humanos , Glicemia , Nanotubos de Carbono/química , Automonitorização da Glicemia , Grafite/química , Eletrodos , Glucose 1-Desidrogenase , GlucoseRESUMO
The postoperative periodontal wound is in a complex physiological environment; the bacteria accumulation, the saliva stimulation, and the food residues retention will aggravate the wound deterioration. Commercial periodontal dressings have been widely used for postoperative periodontal treatment, and there still exists some problems, such as poor biocompatibility, weak adhesion, insufficient antibacterial, and anti-inflammatory properties. In this study, a chitosan-gallic acid graft copolymer (CS-GA) is synthesized as a potential periodontal dressing hydrogel. CS-GA possesses high swelling rate, adjustable degradability, self-healing ability, biocompatibility, strong adhesion ability, high mechanical properties and toughness. Furthermore, CS-GA has good scavenging ability for ·OH, O2 - , and 1 O2. And CS-GA has good inhibition effect on different bacterial through bacterial membranes damage. CS-GA can stop bleeding in a short time and adsorb erythrocytes to form physical blood clots to enhance the hemostatic performance. In addition, CS-GA can reduce inflammatory factors expressions, increase collagen fibers deposition, and neovascularization to promote wounds healing, which makes it as a potential periodontal dressing for postoperative tissue restoration.
Assuntos
Quitosana , Humanos , Quitosana/química , Ácido Gálico/farmacologia , Curativos Periodontais , Hidrogéis/química , Cicatrização , Polímeros/farmacologia , Aderências Teciduais , Antibacterianos/químicaRESUMO
Objective: The aim of this study was to investigate the clinical efficacy of closed manipulation combined with splinting in the treatment of displaced distal radial and ulnar fractures in children. Methods: A total of 82 children with displaced fractures of the distal radial and ulnar segment who met the inclusion criteria and were treated as outpatients or inpatients in the orthopedic department of Guangzhou Orthopedic Hospital, from January 2016 to June 2022 were randomly divided into an observation group and a control group: 41 children in the observation group were treated with closed manipulation combined with splint fixation; 41 children in the control group were fixed with incisional repositioning elastic nails combined with internal plates. The Anderson efficacy grading, visual analog scale (VAS) score, fracture healing time, treatment cost, hospital days, and complications were observed and compared between the two groups. Result: The efficacy was evaluated according to the Anderson forearm fracture efficacy evaluation criteria, and the results of statistical analysis showed no statistically significant differences between the two groups (P > 0.05). At 3 and 7 weeks after treatment, the VAS scores of children in both groups decreased (P < 0.05), and the VAS scores in the observation group were significantly lower than those in the control group (P < 0.05), indicating that the observation group had a significant advantage in the relief of pain after treatment. The fractures healed in both groups after treatment with the two different methods, and the difference in healing time between the two groups was not statistically significant (P > 0.05). The length of hospital stay, treatment cost, and complication ratio were significantly lower in the observation group than in the control group (P < 0.05). Conclusion: In children with displaced fractures of the distal radial and ulnar segments, treatment by manual repositioning with external splinting can achieve satisfactory results with simple operation, low cost, short hospital stay, and few complications, which is especially suitable to be promoted in primary hospitals and has good social benefits.
RESUMO
The concept of network resilience has gained increasing attention in the last few decades owing to its great potential in strengthening and maintaining complex systems. From network-based approaches, researchers have explored resilience of real ecological systems comprising diverse types of interactions, such as mutualism, antagonist, and predation, or mixtures of them. In this paper, we propose a dimension-reduction method for analyzing the resilience of hybrid herbivore-plant-pollinator networks. We qualitatively evaluate the contribution of species toward maintaining resilience of networked systems, as well as the distinct roles played by different categories of species. Our findings demonstrate that the strong contributors to network resilience within each category are more vulnerable to extinction. Notably, among the three types of species in consideration, plants exhibit a higher likelihood of extinction, compared to pollinators and herbivores.
RESUMO
Osteoporotic fracture (OPF) is a prevalent skeletal disease in the middle-aged and elderly. In clinical practice, Jianshen Decoction (JSD) has been used to treat OPFs. However, the specific effective components and mechanisms of JSD on OPF have not been explored. Therefore, this study used bioinformatics analysis combined with molecular dynamics simulation validation to explore the molecular mechanism of JSD treatment of OPF. Public databases (TCMSP, Batman TCM) were used to find the effective active components and corresponding target proteins of JSD (screening conditions: OB ≥ 30%, drug-likeness ≥ 0.18, half-life ≥ 4). Differentially expressed genes (DEGs) related to OPF lesions were obtained based on the gene expression omnibus database (screening conditions: adjust P value < .01, | log2 FC | ≥ 1.0). The BisoGenet plug-in and the CytoNCA plug-in of Cytoscape were used to derive the potential core target proteins of JSD in the treatment of OPF. The JSD active ingredient target interaction network and the JSD-OPF target protein core network were constructed using the Cytoscape software. In addition, the R language Bioconductor package and clusterProfiler package were used to perform gene ontology (GO)/Kyoto Encylopedia Of Genes And Genome (KEGG) enrichment analysis on core genes to explain the biological functions and signal pathways of core proteins. Finally, molecular docking and molecular dynamics simulations were carried out through PyMOL, AutoDockTools 1.5.6, Vina, LeDock, Discovery Studio (DS) 2019, and other software to verify the binding ability of drug active ingredients and core target proteins. A total of 245 targets and 70 active components were identified. Through protein-protein interaction (PPI) network construction, 39 core targets were selected for further research. GO/KEGG enrichment analysis showed that the DNA-binding transcription factor binding, RNA polymerase II-specific DNA-binding transcription factor binding, MAPK signaling pathway, and ErbB signaling pathway were mainly involved. The results of molecular docking and molecular dynamics simulations supported the good interaction between MYC protein and Quercetin/Stigmasterol. In this study, bioinformatics, molecular docking, and molecular dynamics simulations were used for the first time to clarify the active components, molecular targets, and key biological pathways of JSD in the treatment of OPF, providing a theoretical basis for further research.
Assuntos
Medicamentos de Ervas Chinesas , Fraturas por Osteoporose , Humanos , Idoso , Pessoa de Meia-Idade , Simulação de Dinâmica Molecular , Simulação de Acoplamento Molecular , Fraturas por Osteoporose/tratamento farmacológico , Biologia Computacional , Fatores de Transcrição , DNA , Medicamentos de Ervas Chinesas/farmacologia , Medicamentos de Ervas Chinesas/uso terapêutico , Medicina Tradicional ChinesaRESUMO
The biogeographical distribution of plants and animals has been extensively studied, however, the biogeographical patterns and the factors that influence bacterial communities in lakes over large scales are yet to be fully understood, even though they play critical roles in biogeochemical cycles. Here, bacterial community compositional data, geographic information, and environmental factors were integrated for 326 Chinese lakes based on previously published studies to determine the underlying factors that shape bacterial diversity among Chinese lakes. The composition of bacterial communities significantly varied among the three primary climatic regions of China (Northern China, NC; Southern China, SC; and the Tibetan Plateau, TIP), and across two different lake habitats (waters and sediments). Sediment bacterial communities exhibited significantly higher alpha-diversity and distance-decay relationships compared to water communities. The results indicate that the "scale-dependent patterns" of controlling factors, primarily influenced by geographical factors, become increasingly pronounced as the spatial scale increases. At a national scale, geographical factors exerted a dominant influence on both the water and sediment communities across all lakes, as geographical barriers restrict the dispersal of individuals. At smaller spatial scales, temperature-driven selection effects played a greater role in shaping water bacterial community variation in the NC, SC, and TIP, while geographical factors had a stronger association with sediment bacterial community variation in the lakes of the three regions. This synthesis offers novel insights into the ecological factors that determine the distribution of bacteria in Chinese lakes.
Assuntos
Bactérias , Lagos , Lagos/química , China , Ecossistema , Água , Sedimentos GeológicosRESUMO
Precise control of the manipulating force within an appropriate range is crucial to prevent potential damage to the operating object. However, achieving accurate force control through force feedback is challenging in micro-scale applications. This study presents the design of a quasi-zero stiffness-compliant constant-force microgripper with adjustable force output. The parameters of the constant-force mechanism are designed using a model-based optimization method. By utilizing this mechanism, a compliant microgripper capable of providing adjustable constant-force output is developed to overcome the limitation of traditional grippers that offer only a single constant force. Finite element analysis is performed to simulate the behavior and verify the stability of the constant-force output. Furthermore, an experimental platform is constructed to validate the mechanical properties of the developed microgripper. The experimental results demonstrate that the automatically optimized structural parameters enable the microgripper to achieve the desired constant-force value of 2 N with an adjustable range of 0.15 N. These findings provide a further basis for the application and promotion of compliant constant-force structures.
RESUMO
Cis-alkenes are ubiquitous in biological molecules, which makes it greatly significant to develop efficient methods toward construction of cis-olefins. Herein, we reported a facile semi-hydrogenation of alkynes to cis-alkenes in an efficient way with cuprous bromide/tributylphosphine as the catalyst and bis(pinacolato)diboron/methanol as the hydrogen donor. The method features convenient and facile reaction conditions, wide substrate scope, high yields, and high stereoselectivity.
Assuntos
Alcinos , Cobre , Alcinos/química , Cobre/química , Hidrogenação , Alcenos/química , CatáliseRESUMO
Aim: We purposed to evaluate the KCTD10 effects of angiogenesis in diabetic retinopathy (DR). Methods: We induced a DR cell model using high glucose (HG) treatment of HRECs and ARPE-19 cells. A DR rat was established by injecting streptozotocin. Small interference RNA targeted KCTD10 (si-KCTD10) was used to mediate KCTD10 inhibition in cell and animal models. The roles of KCTD10 on cell viability, apoptosis, angiogenesis, and related proteins (VEGF and HIF-1α) were observed by RT-qPCR, Western blot, CCK-8 assay, TUNEL staining, tube formation assay, ELISA, and immunohistochemistry assay. Results: KCTD10 expression was upregulated in DR cells and retinal tissue of DR rats. Treatment of the cells with si-KCTD10 increased cell viability and decreased apoptosis and angiogenesis in DR cells. Inhibition of KCTD10 could reduce the expression of VEGF and HIF-1α in DR cells. Furthermore, KCTD10 inhibition reduced VEGF levels in the retinal tissue of DR rats. Conclusion: This work showed that inhibition of KCTD10 relieved angiogenesis in DR.
Assuntos
Diabetes Mellitus , Retinopatia Diabética , Ratos , Animais , Retinopatia Diabética/genética , Retinopatia Diabética/metabolismo , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/metabolismo , Células Endoteliais/metabolismo , Neovascularização Patológica/genética , Neovascularização Patológica/metabolismo , Retina/metabolismo , Diabetes Mellitus/metabolismoRESUMO
The co-combustion reactivity and kinetics of petroleum coke (PC) and paper sludge-derived hydrochar (PS) were investigated via thermogravimetric analysis. The physical and chemical structure features were also systematically tested. The results show that the combustion process of PS could be divided into three stages, while for PC only one stage could be clarified. Due to high volatile content, developed pore structure and low carbon-order degree, the combustion reactivity of PS was higher than that of PC. Although the ignition property of the blends could be significantly improved by addition of PS, it changed little for the burnout temperature and as a result the combustion intensity was deteriorated. For the samples with addition of PS from 20 % to 80 %, the comprehensive combustion index decreased from 3.69 × 10-15 to 2.12 × 10-15. The Kissinger AkahiraSunose model-free method was used in the co-combustion reaction of PC and PS, and good fitting results were obtained. For different samples with varying addition of PS, the activation energies were in the range of 107.51-198.44 kJ/mol, with the lowest value obtained at 20 % of PS, which was also the optimum proportion for co-combustion of PC and PS.
Assuntos
Coque , Petróleo , Carbono/química , Cinética , EsgotosRESUMO
Collective decision making in a biological motion group requires fast and robust transmission of information. Typically, directional switching information propagation across the whole group obeys a linear dispersion law. However, conventional dynamic collective motion models, such as the Vicsek model and the Couzin model did not take into account ultrafast directional synchronous motions. In the present paper, a multiparticle model is proposed based on inertial spin self-propel action, which can provide adequate description of such group motion. By considering both spin mechanism and collision avoidance, the proposed self-propelled particle spin model can nicely describe collective motion with fast directional switching. By analyzing the order parameter of the group-velocity synchronization, a mechanism of group decision making is revealed, which is based on the difference between two clusters of divergent leaders, showing a transition from the compromising phase (i.e., following the group average) to the preferred phase (i.e., aligning to a leader cluster). The finding provides new insight to the decision-making process of followers when they face with divergent leaders in group motion.
RESUMO
Although the etoposide and carboplatin (EP) combination strategy has been the first-line chemotherapy, patients with extensive-stage disease small-cell lung cancer (SCLC) still have poor survival outcomes. Our retrospective analysis revealed that 46 patients with SCLC only achieved medium overall survival (OS) of 11.6 months after treated by EP. Recently, it was demonstrated that combination therapy of PD1/PD-L1 immune checkpoint blocker and EP could significantly improve the OS of SCLC patients. However, the serious treatment-related toxicity leaded to a high rate of treatment-discontinuation or even death. In the present study, we have developed a novel TPP1-conjugated nanocomplex, abbreviated as TPP1NP-EP, which was co-loaded with carboplatin (CBP) and etoposide (VP16). The TPP1 was a PD-L1 targeting peptide and conjugated on the surface of nanocomplex by a matrix metalloproteinase (MMP-2/9)-cleavable peptide linker sequence PLGLAG. For dual-loading of CBP and VP16, the CBP was chemically conjugated with poly(ethylene glycol) (PEG)-poly(caprolactone) (PCL) by pH-sensitive hydrazone bond and the VP16 was physically encapsulated by emulsion-solvent evaporation method. In vitro and in vivo experiments demonstrated an excellent anti-tumor effect of TPP1NP-EP on SCLC and improved safety. In conclusion, the present study has provided a promising strategy for treatment of malignant SCLC.
Assuntos
Imunoconjugados , Neoplasias Pulmonares , Carcinoma de Pequenas Células do Pulmão , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Antígeno B7-H1 , Carboplatina , Etoposídeo , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/patologia , Peptídeos/uso terapêutico , Estudos Retrospectivos , Carcinoma de Pequenas Células do Pulmão/tratamento farmacológicoRESUMO
OBJECTIVE: The purpose of this study was to explore the factors affecting the quality of life and work of male nurses in Hainan Province, so as to provide a theoretical basis to improve the motivation of male nurses, reduce job-hopping intentions, and maintain the stability of labor force. METHODS: A total of 393 male and 393 female nurses with registered nurse qualifications from 53 hospitals in Hainan Province were selected as the research subjects. The distribution in various hospital departments, quality of life, stress coping ability, social support and job satisfaction were compared. The factors affecting the quality of life of male nurses were analyzed. RESULTS: Male nurses worked mainly in the intensive care unit (ICU), operating rooms and emergency departments, while female nurses worked mainly in general wards. There were significant differences in physical function, general health, social functioning, and mental health between male and female nurses (P<0.05), and female nurses had significantly higher Physical Component Summary and Mental Component Summary scores than male nurses (P<0.05). There was no significant difference in coping styles between male and female nurses in stressful working environments (P>0.05). Male nurses scored significantly lower than female nurses in objective support, subjective support, support utilization and total score (P<0.05), and male nurses exhibited significantly lower job satisfaction than female nurses (P<0.05). Univariate and multivariate analyses showed that years of experience, work unit, monthly income, social support and job satisfaction were the independent risk factors affecting the quality of life of male nurses. CONCLUSION: Male nurses in Hainan Province mostly worked in departments with high work intensity and pressure, and the overall quality of life, social support and job satisfaction were significantly lower than those of female nurses. Therefore, psychological guidance for male nurses should be strengthened, the salary of male nurses should be increased, higher social support should be provided, to reduce job burnout and thus improve their quality of life.
RESUMO
A new layered compound LaOTlF2 is designed and investigated using first-principles calculations in this work. The parent compound is an insulator with an indirect band gap of 3.88 eV. Electron-doping of the parent compound makes the material metallic. In the meantime, several lattice vibrational modes couple strongly to the conduction band, leading to a large electron-phonon coupling constant and conventional superconductivity. The highest superconducting transition temperature Tc is predicted to be approximately 8.6 K with λ about 1.25 in the optimally doped LaO0.95F0.05TlF2, where λ is calculated using the Wannier interpolation technique.
RESUMO
The structure characteristics and combustibility of pyrochar and hydrochar were compared using scanning electron microscopy, nitrogen adsorption, Fourier transform infrared spectrum, Raman spectrum and thermogravimetry. The random pore model was applied to analyze the combustion process of chars. With the temperature increasing, analysis of physical structure revealed that the pore structure of hydrochar was more developed than that of pyrochar. Meanwhile, the hydrothermal process had an advantage over pyrolysis in terms of removing oxygen-containing functional groups and improving the coal rank, mainly attributed to the existence of subcritical water. In addition, the high determination coefficient of random pore model indicated that the model could accurately obtain the kinetic parameters. The activation energies calculated of hydrochars were higher than that of pyrochars, indicating that carbon in hydrochar had a more structural stability. The pyrochar obtained after 220 °C was less combustible than hydrochar due to its severe pore collapse during the combustion process.
RESUMO
A novel tetrahydroxydiboron and nickel chloride cocatalyzed radical cyclization cascade with a broad substrate scope and an ultrashort reaction time was developed. The mechanistic investigation indicated that the reaction might involve a homocleavage of tetrahydroxydiboron and nickel hydride intermediates. This approach enables the simple and efficient synthesis of a series of heteropolycycles.