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(Z)-alkenes are useful synthons but thermodynamically less stable than their (E)-isomers and typically more difficult to prepare. The synthesis of 1,4-hetero-bifunctionalized (Z)-alkenes is particularly challenging due to the inherent regio- and stereoselectivity issues. Herein we demonstrate a general, chemoselective and direct synthesis of (Z)-2-butene-1,4-diol monoesters. The protocol operates within a Pd-catalyzed decarboxylative acyloxylation regime involving vinyl ethylene carbonates (VECs) and various carboxylic acids as the reaction partners under mild and operationally attractive conditions. The newly developed process allows access to a structurally diverse pool of (Z)-2-butene-1,4-diol monoesters in good yields and with excellent regio- and stereoselectivity. Various synthetic transformations of the obtained (Z)-2-butene-1,4-diol monoesters demonstrate how these synthons are of great use to rapidly diversify the portfolio of these formal desymmetrized (Z)-alkenes.
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The fabrication of molecular crystalline materials with fast, multistimuli-responsive behavior and the construction of the corresponding structure-activity relationship are of extraordinary significance for the development of smart materials. In this context, three multistimuli-responsive functional metal-organic polyhedra (MOP), {[Dy2(bcbp)3(NO3)1.5(H2O)7]·Cl4.2·(NO3)0.3·H2O}n (1), {[Dy2(bcbp)4(H2O)8]Cl6}n (2), and {[Eu2(bcbp)4(H2O)10]Cl6·H2O}n (3; bcbp = 1,1'-bis(4-carboxyphenyl)-4,4'-bipyridinium), were successfully prepared and characterized. All of the compounds exhibit rapid and reversible photochromic and electrochromic dual-responsive behaviors. Furthermore, benefiting from the well-defined crystal structure and different responsive behaviors, the photoinduced electron transfer (PIET) process and structure-activity relationship were explored. In addition, considering the excellent photochromic performance, function filter paper and smart organic glass were successfully prepared and used for ink-free printing and UV light detection.
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Disc cutters are essential for full-section hard-rock tunnel boring machines. The performance of these devices directly affects tunnel engineering costs and duration. This paper proposes a sinusoidal variable cross-section (VCS) cutter ring and design method and establishes a digital model. Rock-like materials are simulated with a finite element model, and the model validity is verified via rock simulation mechanics tests. A disc cutter rolling rock simulation model for a linear cutting machine is also established, and simulation tests are performed for single- and three-cutter rolling using sinusoidal VCSs and constant cross-section (CCS) cutter models, respectively. The stress and energy changes for the cutters and rock-like material damage area were compared via simulation, confirming that some sinusoidal VCS cutter rings do less work on rock-like materials and cause larger crushing areas under the same engineering parameters; therefore, these cutter rings have smaller specific energies. The sinusoidal VCS cutter ring performance is 7% greater than that of CCS on average under single-cutter simulation, and the intermediate cutter performance of the intermediate cutter is 9% greater than that of CCS on average under three-cutter simulation. Thus, sinusoidal VCS cutter rings offer improved rock damage performance, and further research and application of this technology will improve the working efficiency of tunnel boring machines.
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Watersheds are an important ecological security barrier and social and economic development area. In order to evaluate the ecological environment quality of arid and semi-arid watersheds more objectively and accurately, based on the remote sensing ecological index (RSEI), the salinity index was introduced to construct a remote sensing ecological index (AWRSEI) suitable for arid and semi-arid watersheds, and the Daihai watershed was taken as an example to analyze its applicability. Based on the AWRSEI model, four phases of Landsat TM/OLI composite images were used to quantitatively evaluate the ecological and environmental quality of the Daihai Basin from 2001 to 2020. The spatio-temporal evolution of the ecological and environmental quality of the Daihai Basin was analyzed using the coefficient of variation and spatial autocorrelation, and the cause analysis and driving factor explanation power analysis were carried out using geographic detectors. The results showed that:â the average correlation coefficient between AWRSEI and various ecological factors was 0.860, which was more representative than that of a single index component. The load positive and negative values and ranking of the first principal component were consistent with those of RSEI, the contribution rate of eigenvalues was 3.69% higher than those of RSEI, and the evaluation results were closer to the real surface conditions, which is suitable for the ecological environment quality assessment of arid watersheds. â¡ The annual average of the AWRSEI index in the Daihai Basin from 2001 to 2020 was 0.427, which indicated a poor ecological environment quality basis. During the study period, the average of AWRSEI showed a fluctuating trend and reached the highest value of 0.502 in 2020. The overall ecological environment quality improved significantly, the deterioration area decreased by 20.51%, and the improvement area increased by 12.71%. In terms of spatial distribution, the ecological environment quality of forest land in the southern and northwestern high-altitude areas of the Daihai Basin was good, whereas that in the northern and southern mid-altitude areas was poor, and that in the northern area was better than that in the southern area. ⢠The average variation coefficient of AWRSEI in the Daihai Basin was 0.280, the ecological environment quality was stable, and the overall change fluctuation was small; the high fluctuation was mainly concentrated in the southern part of the lake and the residential area. There was a significant spatial autocorrelation in the ecological environment quality of the Daihai Basin, and the high-high agglomeration area was mainly distributed in the forest area at high altitude and the cultivated land area at low altitude. Low-low concentration areas were scattered in the middle altitude area. ⣠The improvement of the ecological environment in Daihai Basin from 2001 to 2020 was mainly due to the increase in NDVI and the decrease in NDBSI and NDSI. NDVI and NDBSI were the combination with the strongest interaction and the strongest interpretation of the ecological environment. Land use was the dominant factor of AWRSEI and had the strongest explanatory power. The combination of land use and meteorological factors was the strongest interaction, and the relationship between each driving factor was enhanced.
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Chaos is an important dynamic feature, which generally occurs in deterministic and stochastic nonlinear systems and is an inherent characteristic that is ubiquitous. Many difficulties have been solved and new research perspectives have been provided in many fields. The control of chaos is another problem that has been studied. In recent years, a recurrent neural network has emerged, which is widely used to solve many problems in nonlinear dynamics and has fast and accurate computational speed. In this paper, we employ reservoir computing to control chaos in dynamic systems. The results show that the reservoir calculation algorithm with a control term can control the chaotic phenomenon in a dynamic system. Meanwhile, the method is applicable to dynamic systems with random noise. In addition, we investigate the problem of different values for neurons and leakage rates in the algorithm. The findings indicate that the performance of machine learning techniques can be improved by appropriately constructing neural networks.
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BACKGROUND: Meningioma is the most common type of primary intracranial tumor with 0.1-1% of all primary meningiomas have been reported to develop into metastases. However, there is no proven therapeutic strategy for multiple metastases of meningiomas. CASE PRESENTATION: A 60-year-old female accepted total tumor resection of a right frontal lobe meningioma in September 2018, In October 2021, the patient was admitted to hospital because of cough and shortness of breath and diagnosed with metastatic meningiomas. The computed tomography (CT) scan revealed the presence of large masses in the right thoracic and abdominal cavity. After two cycles of anti-PD-1 and anti-VEGF treatment, the symptoms were relieved and the tumor was necrotic. Follow up to June 21, 2022, the patient has been given eleven cycles of the treatment every 3 weeks without tumor progression. CONCLUSIONS: This case showed combined anti-PD-1 and anti-VEGF treatment stimulates peripheral blood immune cells to kill metastatic meningioma cells. Whether combined immunotherapy is more effective for metastatic meningioma needs further exploration.
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Neoplasias Encefálicas , Neoplasias Meníngeas , Meningioma , Femenino , Humanos , Persona de Mediana Edad , Meningioma/diagnóstico por imagen , Meningioma/tratamiento farmacológico , Meningioma/patología , Neoplasias Meníngeas/diagnóstico por imagen , Neoplasias Meníngeas/tratamiento farmacológico , Neoplasias Meníngeas/patología , Recurrencia Local de Neoplasia , Neoplasias Encefálicas/cirugía , Tomografía Computarizada por Rayos X/métodosRESUMEN
Intervertebral disc degeneration (IDD) development is regulated by miRNA, including inflammatory reactions, cell apoptosis, and degradation of extracellular matrix. Nucleus pulposus cells apoptosis has a absolute influence in the development of IDD. This experiment explores the mechanism of miR-328-5p regulating IDD. Through the analysis of miRNA and mRNA microarray database, we screened the target genes miR-328-5p and WWP2. We verified the expression of miR-328-5p, WWP2, and related apoptotic genes in normal and degenerative nucleus pulposus tissues by qRT-PCR. The expressions of WWP2, Bcl-2, and Bax were detected by qRT-PCR and western blot after transfection to nucleus pulposus cell. The nucleus pulposus cell proliferation and apoptosis after transfection were confirmed by CCK8 and flow cytometry. Luciferase reporter assay and bioinformatics analyzed the targeting relationship between miR-328-5p and WWP2. Firstly, the qRT-PCR experiments confirmed the significant increase of miR-328-5p expression, while significant reduction of WWP2 in a degenerative tissues compared to the normal tissues. Surprisingly, miR-328-5p expression was positively, while that of WWP2 negatively correlated with the degeneration grade of IDD. And we also identified the high expression of Bax and Caspase3, while low expression of Bcl-2 in a degenerative tissues. After miR-328-5p mimic transfected into nucleus pulposus cell, qRT-PCR and western blot confirmed that WWP2 and Bcl-2 expressions were downregulated, while Bax and Caspase3 expressions were upregulated, and the same results were obtained by knocking down WWP2. CCK8 and flow cytometry confirmed that miR-328-5p inhibited the proliferation and induced apoptosis of nucleus pulposus cells. WWP2 is a target gene of miR-328-5p by bioinformatics and luciferase reporter assay. In summary, miR-328-5p targets WWP2 to regulate nucleus pulposus cells apoptosis and then participates in the development of IDD. Furthermore, this study may provide new references and ideas for IDD treatment.
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Degeneración del Disco Intervertebral , Disco Intervertebral , MicroARNs , Núcleo Pulposo , Apoptosis/genética , Humanos , Disco Intervertebral/metabolismo , Degeneración del Disco Intervertebral/genética , Degeneración del Disco Intervertebral/metabolismo , MicroARNs/genética , MicroARNs/metabolismo , Núcleo Pulposo/metabolismo , ARN Mensajero/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Proteína X Asociada a bcl-2/metabolismoRESUMEN
Tartary buckwheat [Fagopyrum tataricum (L.) Gaertn.] is a pseudocereal with strongly abiotic resistance. NACs, one of the largest plant-specific transcription factors (TFs), are involved in various stress responses. However, the characteristics and regulatory mechanisms of NAC TFs remain unclarified clearly in Tartary buckwheat (TB). In this study, it validated that salt, drought, and abscisic acid (ABA) stress significantly up-regulated the expression of NAC TF gene FtNAC31. Its coding protein has a C-terminal transactivated domain and localized in the nucleus, suggesting that FtNAC31 might play a transcriptional activation role in TB. Notably, overexpression of FtNAC31 lowered the seed germination rate upon ABA treatment and enhanced the tolerance to salt and drought stress in transgenetic Arabidopsis. Furthermore, under various stresses, the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) in FtNAC31 overexpressed lines exhibited a sharp increase trend. Meanwhile, the expression levels of several stress-associated genes including RD29A, RD29B, RD22, DREB2B, NCED3, and POD1, were dramatically upregulated in lines overexpressing FtNAC31. Altogether, overproduction of FtNAC31 could enhance the resistance to salt and drought stresses in transgenic Arabidopsis, which most likely functioned in an ABA-dependent way.
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Arabidopsis , Fagopyrum , Ácido Abscísico/metabolismo , Arabidopsis/metabolismo , Catalasa/metabolismo , Sequías , Fagopyrum/genética , Fagopyrum/metabolismo , Regulación de la Expresión Génica de las Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Modificadas Genéticamente/metabolismo , Cloruro de Sodio/metabolismo , Cloruro de Sodio/farmacología , Estrés Fisiológico/genética , Superóxido Dismutasa/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismoRESUMEN
Polyaspartic acid (PASP), a well-known green scale inhibitor for industrial water treatment, might be decomposed with prolonged duration, and its anti-scaling performance against CaCO3 and CaSO4 is diminished at a low concentration (<10 mg L-1) and a high temperature. With semi-ethylenediaminetetraacetic acid (EDTA) tetrasodium salt as the mimicking model, novel phosphorus-free PASP-capped 2-aminoethylamino acid (PASP-ED2A) containing side chains bearing multi-functional groups is rationally designed and successfully prepared via the ring-opening reaction of cheap poly(succinimide) under mild reaction conditions with the assistance of readily available 2-aminoethyl amino acid. The static scale inhibition method is used to evaluate the scale inhibition performance of the as-synthesized PASP derivative. Scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy are utilized to monitor the crystallization process of calcium carbonate and calcium sulfate scales, and density functional theory calculations are conducted to shed light on the relationship between the molecular structure and scale inhibition mechanism of PASP-ED2A. Results show that the as-prepared PASP-ED2A shows better scale inhibition performance for CaCO3 and CaSO4 than PASP with a low concentration, a high temperature, and an extended duration. Particularly, PASP-ED2A with a concentration of 10 mg L-1 exhibits the best scale inhibition performance for CaCO3; its scale inhibition capacity is about two times as much as that of PASP. The reason lies in that the coordination atoms in the molecular structure of PASP-ED2A can chelate with Ca2+ to inhibit the combination of Ca2+ with anions and prevent the generation of CaCO3 and CaSO4 scales. The PASP-ED2A derivative can more efficiently retard the formation and growth of CaCO3 and CaSO4 crystal nuclei and exerts better inhibition performance against CaCO3 and CaSO4 scales than PASP.
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OBJECTIVE: The purpose of this study was to compare the preoperative radiographic features of degenerative lumbar spondylolisthesis (DLS) with and without local coronal imbalance (LCI) and to investigate the surgical outcomes of transforaminal lumbar interbody fusion (TLIF) in the treatment of DLS with LCI at the spondylolisthesis level. DLS with scoliotic disc wedging and/or lateral listhesis at the same involved segment, as well as LCI, constitutes a distinct subgroup. However, previous studies concerning surgical outcomes focused mainly on sagittal profiles. There is a paucity of valid data regarding lumbar coronal alignment and patient-reported outcomes (PROs) after surgery in DLS with LCI. METHODS: The authors reviewed consecutive patients who received TLIF for L4/5 DLS between 2009 and 2018. Patients were assigned to the LCI and non-LCI groups based on preoperative radiographs. Demographics, radiographic parameters related to both sagittal and coronal alignment, and PROs were compared between the 2 groups. RESULTS: There were 21 patients in the LCI and 80 in the non-LCI group. Compared with the non-LCI group, the LCI group was characterized by lower preoperative lumbar lordosis on sagittal alignment (38.3° vs 43.7°, p < 0.05), higher lumbar Cobb angle on coronal alignment (12.4° vs 5.1°, p < 0.05), and worse lumbar coronal balance (18.5 mm vs 6.8 mm, p < 0.05). After surgery, lumbar alignment in the sagittal and coronal planes was significantly improved in the LCI group, whereas no significant changes occurred in the non-LCI group. Scores on the preoperative Oswestry Disability Index and the visual analog scale for back pain and leg pain scores were significantly higher in the LCI group, whereas no differences were found between the 2 groups in the postoperative evaluation (p > 0.05). CONCLUSIONS: DLS with LCI constitutes a distinct subgroup characterized by coronal malalignment and loss of whole lumbar lordosis, which may result in worse PROs. The TLIF procedure allows the reconstruction of the coronal and sagittal lumbar profile and achievement of satisfactory PROs.
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The upgrade of the laser pump time-resolved X-ray probes, namely time-resolved X-ray absorption spectroscopy (TR-XAS) and X-ray diffraction (TR-XRD), implemented at the Beijing Synchrotron Radiation Facility, is described. The improvements include a superbunch fill, a high-efficiency fluorescence collection, an efficient spatial overlap protocol and a new data-acquisition scheme. After upgrade, the adequate TR-XAS signal is now obtained in a 0.3â mM solution, compared with a 6â mM solution in our previous report. Furthermore, to extend application in photophysics, the TR-XAS probe is applied on SrCoO2.5 thin film. And for the first time, TR-XAS is combined with TR-XRD to simultaneously detect the kinetic trace of structural changes in thin film.
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Osteosarcoma is the most common bone tumor in children and young adults. Although the microRNAs (miRNA) expression analyses of osteosarcoma have been performed previously, the construction of miRNA-messenger RNA (mRNA) networks for osteosarcoma is needed. This study aimed to identify osteosarcoma-related miRNAs through analyzing the microarray datasets and to construct the regulatory network of miRNA-mRNA for human osteosarcoma. The datasets were extracted from the Gene Expression Omnibus and the differentially expressed miRNAs were screened through the limma package in Bioconductor. Genes targeted by the differentially expressed miRNAs were screened out by using the Miranda, MirTarget2, PicTar, PITA, and TargetScan databases. The predicted target genes were further analyzed by Gene Ontology and pathway enrichment analysis and a regulatory network of differentially expressed miRNAs and their target osteosarcoma-associated genes was constructed. A total of 36 downregulated miRNAs and 182 upregulated miRNAs were identified in osteosarcoma samples compared with normal samples and 397 target genes for upregulated miRNAs and 222 target genes for downregulated miRNAs were obtained. The enriched pathways for target genes of differentially expressed miRNAs included transcriptional misregulation in cancer, the AMPK signaling pathway, and MAPK signaling pathway. In the regulatory network, has-miR-199a-5p targeted the highest number of genes and nemo-like kinase (NLK) was targeted by five miRNAs (hsa-miR-140-5p, hsa-miR-107, hsa-miR-324-5p, hsa-miR-199a-5p, and hsa-miR-28-5p). The has-miR-324-5p targets NLK, TGFB2, and PPARG. These miRNAs and their target genes may serve as potential therapeutic targets of osteosarcoma.
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Redes Reguladoras de Genes/genética , MicroARNs/genética , Osteosarcoma/genética , ARN Mensajero/genética , Línea Celular Tumoral , Regulación Neoplásica de la Expresión Génica/genética , Humanos , MAP Quinasa Quinasa 1/genética , Osteosarcoma/patología , PPAR gamma/genética , Proteínas Serina-Treonina Quinasas/genética , Transducción de Señal/genética , Factor de Crecimiento Transformador beta2/genéticaRESUMEN
Long noncoding RNAs (LncRNAs) have been reported to participate in cancer development, including osteosarcoma. Here, in our study, we observed that lncRNA metastasis-associated lung adenocarcinoma transcription 1 (MALAT1) was remarkably overexpressed in osteosarcoma. However, the role it plays in osteosarcoma proliferation mediated by miR-206/cyclin-dependent kinase 9 (CDK9) axis remains uninvestigated. It was found that miR-206 was decreased and CDK9 was elevated in human osteosarcoma cells including MG63, Saos-2, U2OS, and KHOS compared with human osteoblast cell line hFOB 1.19. In addition, it was exhibited that knockdown of MALAT1 was able to inhibit osteosarcoma cell proliferation, which suggested that MALAT1 played an oncogenic role in osteosarcoma development. Bioinformatics analysis indicated that MALAT1 can function as a competing endogenous RNA by sponging miR-206. Because miR-206 has been identified as a significant tumor suppressive gene in multiple cancers, we validated that mimics of miR-206 can restrain osteosarcoma progression. Furthermore, dual-luciferase reporter assay, RNA binding protein immunoprecipitation, and RNA pull-down assay demonstrated the correlation between miR-206 and MALAT1. Besides these, CDK9 was predicted as a downstream gene of miR-206, and we observed that MALAT1 can regulate osteosarcoma progress by modulating CDK9 expression via sponging miR-206. In conclusion, our study implied that MALAT1/miR-206/CDK9 axis can provide novel insights into the biological mechanism of osteosarcoma progression.
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Quinasa 9 Dependiente de la Ciclina/genética , MicroARNs/genética , Osteosarcoma/genética , ARN Largo no Codificante/genética , Apoptosis/genética , Carcinogénesis/genética , Línea Celular Tumoral , Movimiento Celular/genética , Proliferación Celular/genética , Progresión de la Enfermedad , Regulación Neoplásica de la Expresión Génica/genética , Humanos , Osteosarcoma/patología , Proteínas de Unión al ARN/genéticaRESUMEN
Osteosarcoma is the eighth-most common form of childhood cancer, comprising about 20% of all primary bone cancers. To date, systemic co-expression analysis for this cancer is still insufficient to explain the pathogenesis of poorly understood OC. The objective of this study was to construct a gene co-expression network to predict clusters of candidate genes involved in the pathogenesis of osteosarcoma. First, we contributed co-expression modules via weighted gene co-expression network analysis (WGCNA) and investigated the functional enrichment analysis of co-expression genes in terms of GO and KEGG. In result, seven co-expression modules were identified, containing 2,228 differentially expressed genes identified from the 22 human osteosarcoma samples. Subsequently, correlation study showed that the hub-genes between pair-wise modules displayed significant differences. Lastly, functional enrichment analysis of the co-expression modules showed that the module 5 enriched in progresses of immune response, antigen processing, and presentation. In conclusion, we identified essential genes in module 5 which were associated to human osteosarcoma. The key genes in our findings might provide the framework of co-expression gene modules of human osteosarcoma. Further, the functional analysis of these associated genes provides references to understand the mechanism of Osteosarcoma. J. Cell. Biochem. 118: 3953-3959, 2017. © 2017 Wiley Periodicals, Inc.
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Neoplasias Óseas , Bases de Datos Genéticas , Regulación Neoplásica de la Expresión Génica , Redes Reguladoras de Genes , Genes Relacionados con las Neoplasias , Osteosarcoma , Neoplasias Óseas/genética , Neoplasias Óseas/metabolismo , Humanos , Osteosarcoma/genética , Osteosarcoma/metabolismoRESUMEN
Osteosarcoma is an aggressive type of bone tumor that commonly occurs in pediatric age groups. The complete molecular mechanisms behind osteosarcoma formation and progression require elucidation. B7-H3 is a protein of the B7 family that acts as a co-stimulatory molecule with a significant role in adaptive immune responses. The link between B7-H3 expression and its role in different types of cancer remains unclear. B7-H3 protein exhibits different functional roles in in vivo and in vitro conditions that remain controversial. In the present study, a murine model of osteosarcoma was successfully established using a modified protocol so as to easily obtain a low grade and metastatic form of osteosarcoma tissue without complication. Histological data showed that a less organized and highly proliferative mass of cells was observed in the osteosarcoma tissue. A higher expression level of B7-H3 protein was also observed at each advanced stage of osteosarcoma, which indicated the contributory role of the protein in the development of the primary and metastatic forms of osteosarcoma. Immunohistochemistry was performed, which showed that the overexpression of B7-H3 protein in the metastatic form of osteosarcoma may be associated with its migration and invasion.
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The electronic state evolution of single bilayer (1BL) Bi(1 1 1) deposited on three-dimensional (3D) Bi2Se x Te3-x topological insulators at x = 0, 1.26, 2, 2.46, 3 is systematically investigated by angle-resolved photoemission spectroscopy (ARPES). Our results indicate that the electronic structures of epitaxial Bi films are strongly influenced by the substrate especially the topmost sublayer near the Bi films, manifesting in two main aspects. First, the Se atoms cause a stronger charge transfer effect, which induces a giant Rashba-spin splitting, while the low electronegativity of Te atoms induces a strong hybridization at the interface. Second, the lattice strain notably modifies the band dispersion of the surface bands. Furthermore, our experimental results are elucidated by first-principles band structure calculations.
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PURPOSE: To investigate the anticancer properties implicated in a natural triterpenoid (pristimerin)-induced apoptosis and inhibited proliferation in human hepatocellular carcinoma (HCC) HepG2 cell line. METHODS: The cytotoxic activity of pristimerin in HepG2 cells was determined by MTT assay. Apoptotic morphology was observed by fluorescence microscope with Hoechst 33258 staining and percent apoptosis was measured by annexin V/PI double staining. DiOC6 for mitochondrial potential (ΔΨm) and DCFH-DA for reactive oxygen species (ROS) were determined by flow cytometry. Changes of apoptotic- related proteins were analysed by Western blot. RESULTS: Pristimerin exerted a potent cytotoxic effect on HepG2 cells. After HepG2 cells were treated with pristimerin, typical apoptotic bodies, increasing the proportion of apoptotic annexin V-positive cells and activation of caspase-3 were detected in a dose-dependent manner. It was intriguing that pristimerin increased the generation of ROS with a collapse of the mitochondrial membrane potential in the cells. In addition, there was significant change in other mitochondrial membrane proteins triggered by pristimerin, such as Bcl-2 and Bax. Pristimerin also effectively induced subsequent release of cytochrome C from mitochondria into the cytosol, downregulated EGFR protein expression and inhibited downstream signaling pathways in HepG2 cells. Pretreatment with N-acetylcysteine (NAC) blocked ROS generation and resulted in loss of mitochondrial membrane potential, release of cytochrome C and apoptosis induced by pristimerin. CONCLUSION: These data indicate that ROS play an essential role in the induction of apoptosis by pristimerin in HepG2 cells.