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1.
Acta Biochim Biophys Sin (Shanghai) ; 56(4): 621-633, 2024 04 25.
Artigo em Inglês | MEDLINE | ID: mdl-38516704

RESUMO

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease, with a global prevalence of 25%. Patients with NAFLD are more likely to suffer from advanced liver disease, cardiovascular disease, or type II diabetes. However, unfortunately, there is still a shortage of FDA-approved therapeutic agents for NAFLD. Lian-Mei-Yin (LMY) is a traditional Chinese medicine formula used for decades to treat liver disorders. It has recently been applied to type II diabetes which is closely related to insulin resistance. Given that NAFLD is another disease involved in insulin resistance, we hypothesize that LMY might be a promising formula for NAFLD therapy. Herein, we verify that the LMY formula effectively reduces hepatic steatosis in diet-induced zebrafish and NAFLD model mice in a time- and dose-dependent manner. Mechanistically, LMY suppresses Yap1-mediated Foxm1 activation, which is crucial for the occurrence and development of NAFLD. Consequently, lipogenesis is ameliorated by LMY administration. In summary, the LMY formula alleviates diet-induced NAFLD in zebrafish and mice by inhibiting Yap1/Foxm1 signaling-mediated NAFLD pathology.


Assuntos
Diabetes Mellitus Tipo 2 , Resistência à Insulina , Hepatopatia Gordurosa não Alcoólica , Humanos , Camundongos , Animais , Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , Hepatopatia Gordurosa não Alcoólica/etiologia , Hepatopatia Gordurosa não Alcoólica/metabolismo , Lipogênese , Peixe-Zebra , Diabetes Mellitus Tipo 2/metabolismo , Fígado/metabolismo , Dieta Hiperlipídica , Fatores de Transcrição/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Lipídeos , Camundongos Endogâmicos C57BL , Proteína Forkhead Box M1/metabolismo
2.
Biochem Genet ; 62(1): 176-192, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37306827

RESUMO

Bone defects have remained a clinical problem in current orthopedics. Bone marrow mesenchymal stem cells (BM-MSCs) with multi-directional differentiation ability have become a research hotspot for repairing bone defects. In vitro and in vivo models were constructed, respectively. Alkaline phosphatase (ALP) staining and alizarin red staining were performed to detect osteogenic differentiation ability. Western blotting (WB) was used to detect the expression of osteogenic differentiation-related proteins. Serum inflammatory cytokine levels were detected by ELISA. Fracture recovery was evaluated by HE staining. The binding relationship between FOXC1 and Dnmt3b was verified by dual-luciferase reporter assay. The relationship between Dnmt3b and CXCL12 was explored by MSP and ChIP assays. FOXC1 overexpression promoted calcium nodule formation, upregulated osteogenic differentiation-related protein expression, promoted osteogenic differentiation, and decreased inflammatory factor levels in BM-MSCs, and promoted callus formation, upregulated osteogenic differentiation-related protein expression, and downregulated CXCL12 expression in the mouse model. Furthermore, FOXC1 targeted Dnmt3b, with Dnmt3b knockdown decreasing calcium nodule formation and downregulating osteogenic differentiation-related protein expression. Additionally, inhibiting Dnmt3b expression upregulated CXCL12 protein expression and inhibited CXCL12 methylation. Dnmt3b could be binded to CXCL12. CXCL12 overexpression attenuated the effects of FOXC1 overexpression and inhibited BM-MSCs osteogenic differentiation. This study confirmed that the FOXC1-mediated regulation of the Dnmt3b/CXCL12 axis had positive effects on the osteogenic differentiation of BM-MSCs.


Assuntos
Células-Tronco Mesenquimais , MicroRNAs , Camundongos , Animais , Osteogênese , Cálcio/metabolismo , Cálcio/farmacologia , Diferenciação Celular , Citocinas/metabolismo , Células-Tronco Mesenquimais/metabolismo , Células Cultivadas , MicroRNAs/metabolismo
3.
Front Cell Dev Biol ; 11: 1190266, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37476154

RESUMO

Recent studies have demonstrated that stem cells have attracted much attention due to their special abilities of proliferation, differentiation and self-renewal, and are of great significance in regenerative medicine and anti-aging research. Hence, finding natural medicines that intervene the fate specification of stem cells has become a priority. Ginsenosides, the key components of natural botanical ginseng, have been extensively studied for versatile effects, such as regulating stem cells function and resisting aging. This review aims to summarize recent progression regarding the impact of ginsenosides on the behavior of adult stem cells, particularly from the perspective of proliferation, differentiation and self-renewal.

4.
Antioxidants (Basel) ; 12(4)2023 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-37107295

RESUMO

Aging is a complex process of impaired physiological integrity and function, and is associated with increased risk of cardiovascular disease, diabetes, neurodegeneration, and cancer. The cellular environment of the aging brain exhibits perturbed bioenergetics, impaired adaptive neuroplasticity and flexibility, abnormal neuronal network activity, dysregulated neuronal Ca2+ homeostasis, accumulation of oxidatively modified molecules and organelles, and clear signs of inflammation. These changes make the aging brain susceptible to age-related diseases, such as Alzheimer's and Parkinson's diseases. In recent years, unprecedented advances have been made in the study of aging, especially the effects of herbal/natural compounds on evolutionarily conserved genetic pathways and biological processes. Here, we provide a comprehensive review of the aging process and age-related diseases, and we discuss the molecular mechanisms underlying the therapeutic properties of herbal/natural compounds against the hallmarks of brain aging.

5.
J Exp Clin Cancer Res ; 42(1): 96, 2023 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-37085881

RESUMO

BACKGROUND: Hepatocellular carcinoma (HCC) is one of the most common and lethal cancers worldwide, but current treatment options remain limited and cause serious life-threatening side effects. Aberrant FGFR4 signaling has been validated as an oncogenic driver of HCC, and EZH2, the catalytic subunit of the PRC2 complex, is a potential factor that contributes to acquired drug resistance in many tumors, including HCC. However, the functional relationship between these two carcinogenic factors, especially their significance for HCC treatment, remains unclear. In this study, we systematically evaluated the feasibility of a combination therapy targeting FGFR4 and EZH2 for HCC. METHODS: RNA sequencing data of patients with Liver hepatocellular carcinoma (LIHC) from The Cancer Genome Atlas (TCGA) were analyzed to determine FGFR4 and EZH2 expression and their interaction with prognosis. Moreover, the HCC cell lines, zebrafish/mouse HCC xenografts and zebrafish HCC primary tumors were treated with FGFR4 inhibitor (Roblitinib) and/or EZH2 inhibitor (CPI-169) and then subjected to cell proliferation, viability, apoptosis, and tumor growth analyses to evaluate the feasibility of combination therapy for HCC both in vitro and in vivo. Furthermore, RNA-Seq was performed in combination with ChIP-Seq data analysis to investigate the critical mechanism underlying the combination treatment with Roblitinib and CPI-169. RESULTS: EZH2 accumulated through the non-canonical NF-kB signaling in response to FGFR4 inhibitor treatment, and the elevated EZH2 levels led to the antagonism of HCC against Roblitinib (FGFR4 inhibitor). Notably, knockdown of EZH2 sensitized HCC cells to Roblitinib, while the combination treatment of Roblitinib and CPI-169 (EZH2 inhibitor) synergistically induced the HCC cell apoptosis in vitro and suppressed the zebrafish/mouse HCC xenografts and zebrafish HCC primary tumors development in vivo. Moreover, Roblitinib and CPI-169 synergistically inhibited HCC development via repressing YAP signaling. CONCLUSIONS: Collectively, our study highlighted the potential of the therapeutic combination of FGFR4 and EZH2 inhibitors, which would provide new references for the further development of clinical treatment strategies for HCC.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Proteínas de Sinalização YAP , Animais , Humanos , Camundongos , Apoptose , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Linhagem Celular Tumoral , Proliferação de Células , Proteína Potenciadora do Homólogo 2 de Zeste/antagonistas & inibidores , Proteína Potenciadora do Homólogo 2 de Zeste/metabolismo , Inibidores Enzimáticos/uso terapêutico , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Receptor Tipo 4 de Fator de Crescimento de Fibroblastos/antagonistas & inibidores , Receptor Tipo 4 de Fator de Crescimento de Fibroblastos/metabolismo , Peixe-Zebra , Proteínas de Peixe-Zebra , Proteínas de Sinalização YAP/efeitos dos fármacos , Proteínas de Sinalização YAP/metabolismo
6.
Antioxidants (Basel) ; 12(2)2023 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-36829855

RESUMO

Ginsenosides, active substances in Panax ginseng C. A. Meyer (ginseng), extend lifespan in multiple species, ameliorate age-associated damage, and limit functional decline in multiple tissues. However, their active components and their molecular mechanisms are largely unknown. Here, ginsenoside Rg1 (Rg1) promoted longevity in Saccharomyces cerevisiae. Treatment with Rg1 decreased aging-mediated surface wrinkling, enhanced stress resistance, decreased reactive oxygen species' production and apoptosis, improved antioxidant enzyme activity, and decreased the aging rate. Proteomic analysis indicated that Rg1 delays S. cerevisiae senescence by regulating metabolic homeostasis. Protein-protein interaction networks based on differential protein expression indicated that CDC19, a homologue of pyruvate kinase, and SDH2, the succinate dehydrogenase iron-sulfur protein subunit, might be the effector proteins involved in the regulation by Rg1. Further experiments confirmed that Rg1 improved specific parameters of mitochondrial bioenergetics and core enzymes in the glycolytic pathway. Mutant strains were constructed that demonstrated the relationships between metabolic homeostasis and the predicted target proteins of Rg1. Rg1 could be used in new treatments for slowing the aging process. Our results also provide a useful dataset for further investigations of the mechanisms of ginseng in aging.

7.
J Nanobiotechnology ; 21(1): 57, 2023 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-36803772

RESUMO

BACKGROUND: Globally, millions of patients suffer from regenerative deficiencies, such as refractory wound healing, which is characterized by excessive inflammation and abnormal angiogenesis. Growth factors and stem cells are currently employed to accelerate tissue repair and regeneration; however, they are complex and costly. Thus, the exploration of new regeneration accelerators is of considerable medical interest. This study developed a plain nanoparticle that accelerates tissue regeneration with the involvement of angiogenesis and inflammatory regulation. METHODS: Grey selenium and sublimed sulphur were thermalized in PEG-200 and isothermally recrystallised to composite nanoparticles (Nano-Se@S). The tissue regeneration accelerating activities of Nano-Se@S were evaluated in mice, zebrafish, chick embryos, and human cells. Transcriptomic analysis was performed to investigate the potential mechanisms involved during tissue regeneration. RESULTS: Through the cooperation of sulphur, which is inert to tissue regeneration, Nano-Se@S demonstrated improved tissue regeneration acceleration activity compared to Nano-Se. Transcriptome analysis revealed that Nano-Se@S improved biosynthesis and ROS scavenging but suppressed inflammation. The ROS scavenging and angiogenesis-promoting activities of Nano-Se@S were further confirmed in transgenic zebrafish and chick embryos. Interestingly, we found that Nano-Se@S recruits leukocytes to the wound surface at the early stage of regeneration, which contributes to sterilization during regeneration. CONCLUSION: Our study highlights Nano-Se@S as a tissue regeneration accelerator, and Nano-Se@S may provide new inspiration for therapeutics for regenerative-deficient diseases.


Assuntos
Nanocompostos , Nanopartículas , Selênio , Embrião de Galinha , Humanos , Camundongos , Animais , Selênio/farmacologia , Selênio/química , Peixe-Zebra/metabolismo , Espécies Reativas de Oxigênio , Cicatrização , Nanopartículas/química , Inflamação , Enxofre
8.
J Hazard Mater ; 447: 130747, 2023 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-36680903

RESUMO

Triclocarban (TCC) is a widely used environmental endocrine-disrupting chemical (EDC). Articular injury of EDCs has been reported; however, whether and how TCCs damage the joint have not yet been determined. Herein, we revealed that exposure to TCC caused osteoarthritis (OA) within the zebrafish anal fin. Mechanistically, TCC stimulates the expression of DNMT1 and initiates DNA hypermethylation of the type II collagen coding gene, which further suppresses the expression of type II collagen and other extracellular matrices. This further results in decreased cartilage tissue and narrowing of the intraarticular space, which is typical of the pathogenesis of OA. The regulation of OA occurrence by TCC is conserved between zebrafish cartilage tissue and human chondrocytes. Our findings clarified the hazard and potential mechanisms of TCC towards articular health and highlighted DNMT1 as a potential therapeutic target for OA caused by TCC.


Assuntos
Cartilagem Articular , Osteoartrite , Animais , Humanos , Peixe-Zebra/metabolismo , Colágeno Tipo II/genética , Colágeno Tipo II/metabolismo , Cartilagem Articular/metabolismo , Cartilagem Articular/patologia , Osteoartrite/induzido quimicamente , Osteoartrite/genética , Osteoartrite/metabolismo , Epigênese Genética , DNA (Citosina-5-)-Metiltransferase 1/genética , DNA (Citosina-5-)-Metiltransferase 1/metabolismo , Proteínas de Peixe-Zebra/genética
9.
Molecules ; 27(22)2022 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-36431966

RESUMO

Cervical cancer is a common gynecological malignancy afflicting women all over the world. Ginsenoside Rh2 (GRh2), especially 20(S)-GRh2, is a biologically active component in the natural plant ginseng, which can exhibit anticancer effects. Here, we aimed to investigate the effect of 20(S)-GRh2 on cervical cancer and elucidate the underlying mechanism through RNA-seq. In this study, the CCK-8 assay showed that 20(S)-GRh2 inhibited HeLa cell viability in a time- and dose-dependent manner. Caspase 3 activity and Annexin V staining results showed that 20(S)-GRh2 induced apoptosis of HeLa cells. Gene function enrichment analysis revealed that the biological process gene ontology (GO) terms were associated with the apoptotic signaling pathway. Biological process GO terms' similarity network indicated that apoptosis might be from endoplasmic reticulum stress (ERs). Kyoto Encyclopedia of Genes and Genomes enrichment analysis revealed that 20(S)-GRh2 primarily modulates apoptosis pathway genes. Combined protein-protein interaction network, hub gene screening, and qPCR validation data showed that ERs-related genes (ATF4 and DDIT3) and the downstream apoptotic genes (JUN, FOS, BBC3, and PMAIP1) were potential novel targets of 20(S)-GRh2-inducing cervical cancer cell apoptosis. Differential transcript usage analysis indicated that DDIT3 is also a differential transcript and its usage of the isoform (ENST00000552740.5) was reduced by 20(S)-GRh2. Molecular docking suggested that 20(S)-GRh2 binds to the targets (ATF4, DDIT3, JUN, FOS, BBC3, and PMAIP1) with high affinity. In conclusion, our findings indicated that 20(S)-GRh2 might promote ERs-related apoptosis of cervical cancer cells by regulating the DDIT3-based targets' signal pathway. The role of 20(S)-GRh2 at the transcriptome level provides novel targets and evidence for the treatment of cervical cancer.


Assuntos
Estresse do Retículo Endoplasmático , Neoplasias do Colo do Útero , Feminino , Humanos , Células HeLa , Neoplasias do Colo do Útero/tratamento farmacológico , Neoplasias do Colo do Útero/genética , Simulação de Acoplamento Molecular , Apoptose , Proteínas Reguladoras de Apoptose , Expressão Gênica
11.
Bioact Mater ; 15: 131-144, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35386336

RESUMO

Selenium (Se) is an essential trace element involved in nearly all human physiological processes but suffers from a narrow margin between benefit and toxicity. The nanoform of selenium has been proven shown to be more bioavailable and less toxic, yet significant challenges remain regarding the efficient and feasible synthesis of biologically active nanoselenium. In addition, although nanoselenium has shown a variety of biological activities, more interesting nanoselenium features are expected. In this work, hydrosoluble nanoselenium termed Nano-Se in the zero oxidation state was synthesized between gray Se and PEG. A zebrafish screen was carried out in zebrafish larvae cocultured with Nano-Se. Excitingly, Nano-Se promoted the action of the FGFR, Wnt, and VEGF signaling pathways, which play crucial roles in tissue regeneration. As expected, Nano-Se not only achieved the regeneration of zebrafish tail fins and mouse skin but also promoted the repair of skin in diabetic mice while maintaining a profitable safe profile. In brief, the Nano-Se reported here provided an efficient and feasible method for bioactive nanoselenium synthesis and not only expanded the application of nanoselenium to regenerative medicine but also likely reinvigorated efforts for discovering more peculiarunique biofunctions of nanoselenium in a great variety of human diseases.

12.
Handchir Mikrochir Plast Chir ; 54(2): 149-154, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35419784

RESUMO

BACKGROUND: The biological mechanism of Dupuytren's contracture needs to be further studied in order to minimize postoperative recurrence and provide a pathological basis for the development of new therapeutic targets. METHODS: HE staining, immunohistochemistry, PCR and western blotting were performed in pathological palmar aponeurosis specimens and normal palmar aponeurosis tissues for comparative study. RESULTS: (1) TNF-α expression was up-regulated: TNF-α mRNA was more highly expressed in the pathological tissues of DD patients than in the CT group, P < 0.05, and the difference between the two groups was statistically significant; (2) Dkk-1 expression was down-regulated: Dkk-1 mRNA was lower expressed in the pathological tissues of DD patients than in the CT group, P < 0.05, and the difference between the two groups was statistically significant; (3) TGF-ß1 expression was up-regulated: TGF-ß1 mRNA was higher expressed in the pathological tissues of DD patients than in the CT group, P < 0.05, and the difference between the two groups was statistically significant; (4) Pearson correlation analysis suggested that TNF-α expression was positively correlated with TGF-ß1 expression, TNF-α expression was negatively correlated with DKK-1 expression, and TGF-ß1 expression was negatively correlated with DKK-1 expression. CONCLUSION: TNF-α, DKK-1 and TGF-ß1 may play a role in the pathogenesis of palmar aponeurosis contracture, and there is a relationship between them. The study of the relationship between the three and their related signaling pathways provides a therapeutic target and a basis for the prevention and early treatment of palmar aponeurotic contracture.


Assuntos
Contratura de Dupuytren , Peptídeos e Proteínas de Sinalização Intercelular , Fator de Crescimento Transformador beta1 , Fator de Necrose Tumoral alfa , Contratura de Dupuytren/genética , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/genética , RNA Mensageiro/genética , Fator de Crescimento Transformador beta1/genética , Fator de Necrose Tumoral alfa/genética
13.
Kaohsiung J Med Sci ; 36(1): 35-42, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31729834

RESUMO

Osteoporosis is a skeleton disease affecting 55% of people over age 60, and the number is still increasing due to an ageing population. One method to prevent osteoporosis is to increase the formation of new bone while preventing the resorption of older bone. Thus, osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) is of great importance in improving the treatment of osteoporosis. On the other hand, glucocorticoids (GCs) are widely used to treat the chronic inflammatory disorders, but long-term exposure to GCs can induce osteoporosis. In present study, we treated BMSCs with dexamethasone (DEX) to simulate GC-induced osteoporosis. MTT assay, ALP activity, and Alizarin Red were used to evaluate the role miRNA-291a-3p in the DEX-induced osteogenic differentiation suppression. Further, we used qPCR and western blot to investigate the mechanisms of miRNA-291a-3p affecting BMSCs differentiation. The results showed that miRNA-291a-3p could improve the cell viability, osteogenic differentiation, and ALP activity, which are suppressed by DEX in BMSCs. Furthermore, we found that the osteogenesis genes Runx2, DMP1, and ALP were upregulated whereas the lipogenic genes C/EBPα and PPARγ were downregulated when miRNA-291a-3p mimics were transfected. Additionally, we demonstrated that miRNA-291a-3p promoted BMSCs' osteogenic differentiation by directly suppressing DKK1 mRNA and protein expression and subsequently activating Wnt/ß-catenin signaling pathway. Our study suggests that miR-291a-3p plays an important role in preventing osteoporosis and may serve as a potential miRNA osteoporosis biomarker.


Assuntos
Dexametasona/toxicidade , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo , MicroRNAs/metabolismo , Osteoporose/induzido quimicamente , Osteoporose/metabolismo , Animais , Western Blotting , Diferenciação Celular/efeitos dos fármacos , Sobrevivência Celular/genética , Sobrevivência Celular/fisiologia , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/genética , Masculino , MicroRNAs/genética , Osteogênese/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley
14.
Exp Mol Pathol ; 107: 158-164, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30768922

RESUMO

BACKGROUNDS: Osteoactivin (OA) is a key regulator promoting bone marrow stromal cells osteogenesis progress, while Dexamethasone (Dex) could inhibit OA induced osteogenesis and lead to osteoporosis. miR-26b increased during BMSC osteogenesis but whether it participates in this progress is enigma. Osteogenesis is under regulation of canonical Wnt signaling pathway which could serve as potential target for miR-26b. It bears therapeutic potential if miR-26b could regulate osteogenesis and antagonize Dex induced Osteoporosis (OP). METHODS: BMSC were isolated from bone marrow of rats and induced for osteogenesis by OA administration. We detected miR-26b mRNA level together with osteogenesis related genes or Wnt signal pathway related genes by qRT-PCR. BMSC cells with miR-26b inhibitor or mimics revealed the effect of miR-26b on osteogenesis. The osteogenesis efficiency was detected by Alizarin Red staining and ALP activity. Protein level of canonical Wnt signal pathway and other proteins were detected by Western blot. The interaction between miR-26b and GSK3ß was detected by dual luciferase reporter assay. RESULTS: We found that miR-26b was increased during OA induced BMSC osteogenesis. Inhibiting miR-26b could lead to osteogenesis inhibition while miR-26b mimics could promote this progress. The key regulator of Wnt signal pathway GSK3ß is down-regulated when miR-26b was overexpressed, resulting in ß-catenin activation. Since Dex could promote GSK3ß expression and inhibit Wnt signal, miR-26b could also alleviate Dex induced osteogenesis inhibition. CONCLUSION: Our findings indicate that miR-26b promoted BMSC osteogenesis by directly targeting GSK3ß and activating canonical Wnt signal pathway, suggesting miR-26b might be serve as potential therapeutic candidate of osteoporosis.


Assuntos
Glicoproteínas de Membrana/metabolismo , Células-Tronco Mesenquimais/metabolismo , MicroRNAs/metabolismo , Osteogênese/fisiologia , Animais , Diferenciação Celular/fisiologia , Glicogênio Sintase Quinase 3 beta/metabolismo , Ratos , Ratos Sprague-Dawley , Via de Sinalização Wnt/fisiologia , beta Catenina/metabolismo
15.
Sci Rep ; 7(1): 15361, 2017 11 10.
Artigo em Inglês | MEDLINE | ID: mdl-29127373

RESUMO

We investigate a specific diversity phase for phase diversity (PD) phase retrieval, which possesses higher accuracy than common PD, especially for large-scale and high-frequency wavefront sensing. The commonly used PD algorithm employs the image intensities of the focused plane and one defocused plane to build the error metric. Unlike the commonly used PD, we explore a bisymmetric defocuses diversity phase, which employs the image intensities of two symmetrical defocused planes to build the error metric. This kind of diversity phase, named PD-BD (bisymmetric defocuses phase diversity), is analysed with the Cramer-Rao lower bound (CRLB). Statistically, PD-BD shows smaller CRLBs than the commonly used PD, which indicates stronger capacity of phase retrieval. Numerical simulations also verify that PD-BD has higher accuracy of phase retrieval than the commonly used PD when dealing with large-scale and high-frequency wavefront aberrations. To further affirm that PD-BD possesses higher accuracy of wavefront sensing than PD, we also perform a simple verification experiment.

16.
Sci Rep ; 7(1): 10034, 2017 08 30.
Artigo em Inglês | MEDLINE | ID: mdl-28855552

RESUMO

There are more than eight large aperture telescopes (larger than eight meters) equipped with adaptive optics system in the world until now. Due to the limitations such as the difficulties of increasing actuator number of deformable mirror, most of them work in the infrared waveband. A novel two-step high-resolution optical imaging approach is proposed by applying phase diversity (PD) technique to the open-loop liquid crystal adaptive optics system (LC AOS) for visible light high-resolution adaptive imaging. Considering the traditional PD is not suitable for LC AOS, the novel PD strategy is proposed which can reduce the wavefront estimating error caused by non-modulated light generated by liquid crystal spatial light modulator (LC SLM) and make the residual distortions after open-loop correction to be smaller. Moreover, the LC SLM can introduce any aberration which realizes the free selection of phase diversity. The estimating errors are greatly reduced in both simulations and experiments. The resolution of the reconstructed image is greatly improved on both subjective visual effect and the highest discernible space resolution. Such technique can be widely used in large aperture telescopes for astronomical observations such as terrestrial planets, quasars and also can be used in other applications related to wavefront correction.

17.
Opt Express ; 24(19): 22034-42, 2016 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-27661938

RESUMO

An effective method for reducing the sensitivity of phase diversity (PD) technique to Poisson noise is proposed. The denoising algorithm based on blocking-matching and 3D filtering is first introduced in the wavefront sensing field as a preprocessing stage. Then, the PD technique is applied to the denoised images. Results of the numerical simulations and experiments demonstrate that our approach is better than the traditional PD technique in terms of both the root-mean-square error (RMSE) of phase estimates and the structural similarity index metrics (SSIM). The RMSEs of phase estimates on synthetic data are decreased by approximately 40% across noise levels within the range of 58.7-18.8 dB in terms of peak signal-to-noise ratio (PSNR). Meanwhile, the overall decline range of SSIM is significantly decreased from 49% to 9%. The experiment and simulation results are in good agreement. The approach may be widely used in various domains, such as the measurements of intrinsic aberrations in optical systems and compensations for atmospheric turbulence.

18.
Opt Express ; 23(16): 21343-51, 2015 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-26367982

RESUMO

We experimentally demonstrated a metamaterial composed of hexagonal arrays of silver nanowires that exhibits hyperbolic dispersion and negative refraction in the entire visual wavelength range. The nanowires with extremely small size of 10 nm diameter and 15 nm center-to-center distance were fabricated using the reverse hexagonal liquid crystalline phase template containing AgNO(3) solution. Through the experiments of angle dependent reflectance for s-polarization and p-polarization, the dielectric constants were measured in several wavelengths. Calculations and experiments both show hyperbolic dispersion relations from 370 nm to 750 nm which indicates the presence of all-angle negative refraction. For all the experimental wavelengths, the permittivities of the material are in good agreement with the theoretical calculations.

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