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1.
J Hypertens ; 41(4): 638-647, 2023 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-36723459

RESUMO

OBJECTIVES: The aim of this study was to investigate the clinical characteristics of renal artery fibromuscular dysplasia (FMD) in patients in China and identify the cure rate of hypertension after angioplasty. METHODS: Consecutive hypertensive patients with renal artery stenosis caused by FMD who underwent catheter-based angiography, and were followed at two Chinese referral centres, were retrospectively analysed. All patients underwent a detailed investigation, including demographic characteristics, clinical characteristics, biochemical sampling, Doppler ultrasonography of carotid arteries, magnetic resonance angiography (MRA) of the intracranial artery, and CTA or MRA of the abdominal artery and catheter-based renal angiography. Patients were routinely followed up at 1 month, 6 months and every year after the procedure. RESULTS: Among 245 study participants, with a mean diagnosed age of 26.9 ±â€Š9.9 years, 137 (55.9%) were women, and 38 (15.5%) were children. All patients were diagnosed with hypertension at a mean age of 23.4 ±â€Š8.4 years. There were 73.5% focal and 15.2% multivessel cases. Aneurysms, arterial dissections and total occlusions were found in 21.6, 4.1 and 12.2% of patients, respectively. Patients with multifocal FMD were older (26.0 vs. 23.7 years, P  = 0.021) and more often female (70.8 vs. 50.6%, P  = 0.004). Among children with renal FMD, 55.2% were men, and 86.8% were focal. After a median follow-up of 7.0 years, multifocal FMD had a higher cure rate of hypertension than focal FMD after revascularization (71.7 vs. 55.8%, P  = 0.032). CONCLUSION: In a cohort of mostly young Chinese patients, the prevalence of hypertension associated with renal FMD is similar in both sexes. Focal FMDs were more frequent than the multifocal ones and, after angioplasty, were associated with a worse blood pressure outcome.


Assuntos
Displasia Fibromuscular , Hipertensão Renovascular , Hipertensão , Obstrução da Artéria Renal , Masculino , Criança , Humanos , Feminino , Adolescente , Adulto Jovem , Adulto , Hipertensão Renovascular/epidemiologia , Hipertensão Renovascular/etiologia , Displasia Fibromuscular/complicações , Displasia Fibromuscular/epidemiologia , Prevalência , Estudos Retrospectivos , Hipertensão/epidemiologia , Angiografia por Ressonância Magnética/efeitos adversos , Obstrução da Artéria Renal/complicações , Obstrução da Artéria Renal/diagnóstico por imagem , Obstrução da Artéria Renal/epidemiologia , Artérias Carótidas
2.
Diab Vasc Dis Res ; 19(6): 14791641221137355, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36409464

RESUMO

BACKGROUND: Collateral growth plays an important role in the recovery of acute myocardial infarction. C1q/TNF-related protein-2 (CTRP2), a CTRP family member, showed some protective effects on cell survival. In this study, the relationship between CTRP2 and collateral growth was examined. METHODS: C57BL/6 mice were subjected to myocardial ischaemia/reperfusion (I/R), and the expression of CTRP2 and the effect of CTRP2 on infarction size, cardiac function and angiogenesis were examined. The ischaemic hindlimb model was also used to examine the effect of CTRP2. In vitro, CTRP2-mediated regulation of angiogenesis, AKT activation and VEGFR2 expression in endothelial cells was examined. The CTRP2 level associated with good collateral growth was observed in a cohort. RESULTS: I/R reduced CTRP2 expression, and intraperitoneal injection of recombinant CTRP2 protein improved infarction size, cardiac function and angiogenesis. Overexpression of CTRP2 promoted blood refusion and collateral growth in ischaemic hindlimb mice. In vitro, CTRP2 enhanced tube formation and migration in a dose-dependent manner, while CTRP2 increased AKT phosphorylation and VEGFR2 expression. In an observational clinical cohort, CTRP2 levels were significantly increased in patients with good collateral growth, and CTRP2 was negatively associated with poor collateral growth in patients. CONCLUSION: CTRP2 improved cardiac function by promoting collateral growth by promoting AKT-VEGFR2.


Assuntos
Complemento C1q , Infarto do Miocárdio , Animais , Camundongos , Células Endoteliais/metabolismo , Isquemia , Camundongos Endogâmicos C57BL , Infarto do Miocárdio/prevenção & controle , Neovascularização Patológica , Proteínas Proto-Oncogênicas c-akt/metabolismo , Reperfusão
3.
Aging Cell ; 18(4): e12969, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31087498

RESUMO

Aging is an independent risk factor for vascular diseases. Perivascular adipose tissue (PVAT), an active component of the vasculature, contributes to vascular dysfunction during aging. Identification of underlying cell types and their changes during aging may provide meaningful insights regarding the clinical relevance of aging-related vascular diseases. Here, we take advantage of single-cell RNA sequence to characterize the resident stromal cells in the PVAT (PVASCs) and identified different clusters between young and aged PVASCs. Bioinformatics analysis revealed decreased endothelial and brown adipogenic differentiation capacities of PVASCs during aging, which contributed to neointimal hyperplasia after perivascular delivery to ligated carotid arteries. Mechanistically, in vitro and in vivo studies both suggested that aging-induced loss of peroxisome proliferator-activated receptor-γ coactivator-1 α (PGC1α) was a key regulator of decreased brown adipogenic differentiation in senescent PVASCs. We further demonstrated the existence of human PVASCs (hPVASCs) and overexpression of PGC1α improved hPVASC delivery-induced vascular remodeling. Our finding emphasizes that differentiation capacities of PVASCs alter during aging and loss of PGC1α in aged PVASCs contributes to vascular remodeling via decreased brown adipogenic differentiation.


Assuntos
Tecido Adiposo Marrom/citologia , Envelhecimento/fisiologia , Células-Tronco Mesenquimais/metabolismo , Remodelação Vascular/fisiologia , Adipogenia/genética , Adulto , Idoso , Animais , Ponte de Artéria Coronária , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Nus , Camundongos Transgênicos , Pessoa de Meia-Idade , Neointima/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Análise de Sequência de RNA/métodos , Análise de Célula Única/métodos , Transcriptoma
4.
J Hum Hypertens ; 32(8-9): 564-571, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29867136

RESUMO

Recent research suggested that certain small leucine-rich repeat proteoglycans (SLRPs) were involved in the development of atherosclerosis. The present study investigated the relationship between carotid atherosclerosis plaque and the circulating levels of some SLRPs, including decorin, lumican, and osteoglycin, in essential hypertension. In total, 176 essential hypertensive patients were recruited (mean age 62.1 ± 9.4, male 56.8%) in this study and were classified into two groups: patients with carotid artery plaque (n = 105, 60%) and patients without carotid artery plaque (n = 71, 40%). Patients with carotid artery plaque had higher serum concentration of lumican than patients without carotid plaque (58.0 ± 1.6 vs. 52.3 ± 2.1 ng/ml, p = 0.04) after adjusting for conventional cardiovascular risk factors. There were no differences in decorin and osteoglycin between the two groups. Multivariable logistic regression analysis revealed that lumican levels (Odds ratio (OR) per standard deviation increase, 1.598; 95% confidence interval (CI), 1.012 ~ 2.523; p = 0.04), 24-h mean systolic blood pressure (OR, 1.045; 95% CI, 1.012 ~ 1.079; p = 0.006) and the use of angiotensin receptor blocker (OR, 2.813; 95% CI, 1.023 ~ 7.734; p = 0.045) were independently associated with carotid artery plaque. Besides carotid artery plaque, lumican was related to impaired glucose tolerance (r = 0.162, p = 0.046) and adversely related to osteoglycin (r = - 0.273, p < 0.001), whereas unrelated to age, sex, BMI, diabetes, blood pressure, serum lipids, high-sensitivity C-reactive protein, or carotid intima-media thickness in univariate correlation analyses. Circulating lumican was independently associated with carotid atherosclerosis plaque in essential hypertensive patients, indicating that SLRPs might be used as a promising molecular marker for atherosclerosis.


Assuntos
Doenças das Artérias Carótidas/sangue , Hipertensão Essencial/complicações , Proteoglicanos Pequenos Ricos em Leucina/sangue , Idoso , Biomarcadores/sangue , Doenças das Artérias Carótidas/complicações , Doenças das Artérias Carótidas/diagnóstico por imagem , Espessura Intima-Media Carotídea , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
5.
Shock ; 48(3): 321-328, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28362715

RESUMO

INTRODUCTION: Recent studies demonstrated the significant loss of gamma delta T (γδ T) cells in patients with sepsis. Given the distinct functions of γδ T cells in human anti-infection immunity, we are interested in evaluating the phenotype and function of peripheral γδ T cells in septic patients and determining their prognostic implication. METHOD: This prospective study has been conducted in three intensive care units of a university hospital. During the period from October 2014 to June 2015, we enrolled 107 patients who were consecutively admitted and diagnosed with severe sepsis or septic shock (excluding previous immunosuppression) and 45 healthy controls. Using flow cytometry, we analyzed the in vivo percentage of γδ T cells in cluster of differentiation (CD)3 cells from peripheral blood mononuclear cells as well as their expression of surface markers (CD69, natural-killer group 2 member D [NKG2D], programmed death receptor 1 [PD-1]) and intracellular cytokines (interferon-γ [IFN-γ], interleukin [IL]-17, IL-10, transforming growth factor-ß [TGF-ß]). Then we further evaluated the different responses of γδ T cells after the antigen stimulation ex vivo by measuring CD69 and IFN-γ expression. Lastly, we conducted the multiple logistic regressions to analyze the risk factor for prognosis. RESULTS: Compared with control group, γδ T cells in septic patients displayed a decrease in percentage, increase in CD69, decrease in NKG2D, and increase in cytokine expression (pro-inflammatory IFN-γ, IL-17, anti-inflammatory IL-10, TGF-ß) in vivo. After the antigen stimulation ex vivo, both CD69 and IFN-γ expression in γδ T cells were significantly lower in septic patients than control group. Importantly, the decrease in CD69 and IFN-γ expression was more pronounced in non-survivors than survivors. Multiple logistic regression analysis revealed that lower expression of IFN-γ after stimulation is a dependent risk factor that associated with patient 28-day death in septic patients (OR: 0.908 [95% CI: 0.853-0.966]). CONCLUSION: Septic patients showed altered phenotype and function of γδ T cells. The impaired IFN-γ expression by γδ T cells after the antigen stimulation is associated with mortality in septic patients.


Assuntos
Antígenos de Diferenciação/sangue , Citocinas/sangue , Receptores de Antígenos de Linfócitos T gama-delta/sangue , Sepse/sangue , Linfócitos T/metabolismo , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Sepse/mortalidade , Sepse/patologia , Linfócitos T/patologia
6.
Sci Rep ; 7: 40253, 2017 01 16.
Artigo em Inglês | MEDLINE | ID: mdl-28091516

RESUMO

Vascular calcification (VC) is a highly regulated ectopic mineral deposition process involving immune cell infiltration in the vasculatures, which has been recognized to be promoted by hypertension. The matricellular glycoprotein osteopontin (OPN) is strongly induced in myeloid cells as a potential inflammatory mediator of vascular injury. This study aims to examine whether OPN is involved in the regulation of macrophage activation and osteoclast formation in hypertensive subjects with VC. We firstly found an increased proportion of CD11c+CD163- pro-inflammatory peripheral monocytes in hypertensive subjects with VC compared to those without VC by flow cytometric analysis. Primary cultured macrophages from hypertensive subjects with VC also showed altered expression profile of inflammatory factors and higher serum OPN level. Exogenous OPN promoted the differentiation of peripheral monocytes into an alternative, anti-inflammatory phenotype, and inhibited macrophage-to-osteoclast differentiation from these VC patients. In addition, calcified vessels showed increased osteoclasts accumulation accompanied with decreased macrophages infiltration in the of hypertensive subjects. Taken together, these demonstrated that OPN exerts an important role in the monocytes/macrophage phenotypic differentiation from hypertensive patients with VC, which includes reducing inflammatory factor expression and attenuating osteoclast formation.


Assuntos
Hipertensão/imunologia , Mediadores da Inflamação/imunologia , Ativação de Macrófagos , Osteoclastos/imunologia , Osteopontina/imunologia , Calcificação Vascular/imunologia , Diferenciação Celular , Células Cultivadas , Feminino , Humanos , Hipertensão/complicações , Hipertensão/metabolismo , Mediadores da Inflamação/metabolismo , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/metabolismo , Masculino , Pessoa de Meia-Idade , Osteoclastos/metabolismo , Osteopontina/metabolismo , RNA Mensageiro/metabolismo , Calcificação Vascular/complicações , Calcificação Vascular/metabolismo
7.
Cardiovasc Res ; 113(1): 70-80, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-28069703

RESUMO

OBJECTIVE: Osteoglycin (OGN) has been noted for its implication in cardiovascular disease in recent studies. However, the relationship between OGN and angiogenesis remains unknown. Therefore, we aimed to investigate the effect of OGN on ischaemia-induced angiogenesis and to address the underlying mechanisms. METHODS AND RESULTS: The expression of OGN was decreased in a limb ischaemia mouse model. OGN knockout (KO) mice were used to further understand the role of OGN after ischaemia. The perfusion recovery rate after femoral artery ligation was higher in OGN KO mice than in wild-type (WT) mice. The capillary density in the gastrocnemius muscle of the ischaemic limb was also higher in OGN KO mice. Moreover, ex vivo aortic ring explants from OGN KO mice exhibited stronger angiogenic sprouting than those from WT mice. In human umbilical vein endothelial cells (HUVECs), OGN knockdown enhanced endothelial cell (EC) activation, including tube formation, proliferation, and migration. In contrast, OGN overexpression inhibited HUVEC activation. Mechanistic studies revealed that OGN associates with vascular endothelial growth factor receptor 2 (VEGFR2) and negatively regulates the interaction of vascular endothelial growth factor (VEGF) and VEGFR2, thereby negatively modulating the activation of VEGFR2 and its downstream signalling pathways. Consistently, the pro-angiogenic effect of OGN KO was abrogated by VEGFR2 inhibition, supporting the critical role of VEGFR2 signalling in OGN-mediated regulation of angiogenic function. CONCLUSIONS: OGN plays a critical role in negatively regulating ischaemia-induced angiogenesis by inhibiting VEGF-VEGFR2 signalling and thereby attenuating EC tube formation, proliferation, and migration. Thus, OGN may be a novel therapeutic target for ischaemic vascular diseases.


Assuntos
Células Endoteliais da Veia Umbilical Humana/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/deficiência , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Isquemia/metabolismo , Músculo Esquelético/irrigação sanguínea , Neovascularização Fisiológica , Fator A de Crescimento do Endotélio Vascular/metabolismo , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismo , Animais , Movimento Celular , Proliferação de Células , Células Cultivadas , Modelos Animais de Doenças , Predisposição Genética para Doença , Membro Posterior , Peptídeos e Proteínas de Sinalização Intercelular/genética , Isquemia/genética , Isquemia/fisiopatologia , Masculino , Camundongos Knockout , Fenótipo , Interferência de RNA , Recuperação de Função Fisiológica , Fluxo Sanguíneo Regional , Transdução de Sinais , Fatores de Tempo , Técnicas de Cultura de Tecidos , Transfecção
8.
FASEB J ; 31(3): 1120-1129, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-27974594

RESUMO

Perivascular adipose tissue (PVAT)-derived adiponectin (APN) is a secreted adipokine that protects against hypertension-related cardiovascular injury. However, the regulation of APN expression in hypertension remains to be explored. In this study, we demonstrated that down-regulation of APN was associated with complement activation in the PVAT of desoxycorticosterone acetate (DOCA)-salt hypertensive mice. Complement 3-deficient hypertensive mice were protected from ANP decrease in the PVAT. APN deficiency blockaded the protective effects of complement inhibition against hypertensive vascular injury. Mechanistically, complement 5a (C5a)-induced TNF-α secretion from macrophages is required for inhibiting APN expression in adipocytes. Macrophage depletion reversed C5a agonist peptide-induced TNF-α up-regulation and APN down-regulation in the PVAT of DOCA mice. Moreover, we detected increased macrophage infiltration and C5a expression associated with decreased APN expression in adipose tissue from patients with aldosterone-producing adenoma. These results identify a novel interaction between macrophages and adipocytes in the PVAT, where complement-mediated inhibition of APN acts as a potential risk factor for hypertensive vascular inflammation.-Ruan, C.-C., Ma, Y., Ge, Q., Li, Y., Zhu, L.-M., Zhang, Y., Kong, L.-R., Wu, Q-H., Li, F., Cheng, L., Zhao, A. Z., Zhu, D.-L., Gao, P.-J. Complement-mediated inhibition of adiponectin regulates perivascular inflammation and vascular injury in hypertension.


Assuntos
Adipócitos/metabolismo , Adiponectina/metabolismo , Complemento C3/metabolismo , Complemento C5a/metabolismo , Hipertensão/metabolismo , Remodelação Vascular , Adiponectina/genética , Animais , Regulação para Baixo , Humanos , Hipertensão/patologia , Inflamação/metabolismo , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Fator de Necrose Tumoral alfa/metabolismo
9.
J Am Heart Assoc ; 5(12)2016 12 16.
Artigo em Inglês | MEDLINE | ID: mdl-27986757

RESUMO

BACKGROUND: Cyanate has recently gained attention for its role in the pathogenesis of vascular injury. Nonetheless, the effect of cyanate on angiogenesis remains unclear. METHODS AND RESULTS: In this study, we demonstrated that oral administration of cyanate impaired blood perfusion recovery in a mouse hind-limb ischemia model. A reduction in blood perfusion recovery at day 21 was observed in the ischemic tissue of cyanate-treated mice. Likewise, there were fewer capillaries in the ischemic hind-limb tissue of cyanate-exposed mice. Our in vitro study showed that cyanate, together with its carbamylated products, inhibited the migration, proliferation, and tube-formation abilities of endothelial cells. Further research revealed that cyanate regulated angiogenesis partly by interrupting the vascular endothelial growth factor receptor 2/phosphatidylinositol 3-kinase/Akt pathway. The serum concentrations of homocitrulline, a marker of cyanate exposure, were determined in 117 patients with stable angina and chronic total occlusion. Consistent with the antiangiogenic role of cyanate, homocitrulline levels were increased in patients with poor coronary collateralization (n=58) compared with those with high collateralization (n=59; 21.09±13.08 versus 15.54±9.02 ng/mL, P=0.009). In addition, elevated homocitrulline concentration was a strong predictor of poor coronary collateral growth. CONCLUSIONS: Impaired angiogenesis induced by cyanate might contribute to poor coronary collateral growth.


Assuntos
Indutores da Angiogênese/farmacologia , Circulação Colateral/fisiologia , Cianatos/farmacologia , Membro Posterior/irrigação sanguínea , Isquemia/fisiopatologia , Administração Oral , Idoso , Análise de Variância , Angina Estável/diagnóstico por imagem , Angina Estável/fisiopatologia , Animais , Células Cultivadas , Doença Crônica , Citrulina/análogos & derivados , Citrulina/metabolismo , Angiografia Coronária , Oclusão Coronária/diagnóstico por imagem , Oclusão Coronária/fisiopatologia , Cianatos/administração & dosagem , Endotélio Vascular , Feminino , Humanos , Masculino , Camundongos Endogâmicos C57BL , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidores
10.
Chin Med J (Engl) ; 125(6): 1041-6, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22613528

RESUMO

BACKGROUND: Weight gain following smoking cessation increases cardiovascular risk, but its effects on prognosis after percutaneous coronary intervention (PCI) remain unclear. This study aimed to investigate the relationship between weight gain post smoking cessation and one-year clinical outcome in patients who underwent PCI with drug-eluting stent (DES). METHODS: A total of 895 consecutive male smoking patients were divided into quitters (n = 437) and continuers (n = 458) according to their smoking status after PCI. Weight gain, major adverse cardiac events (MACE, including cardiac deaths, myocardial infarction and revascularization), and recurrent angina were recorded during follow-up for one year. RESULTS: Average weight gain in quitters was more than that in continuers (1.5 kg vs. -0.03 kg, P < 0.001). Weight was unchanged or increased by more than 1.5 kg in 78.17% of continuers, while 50.57% of quitters had a weight gain of less than 1.5 kg. Compared with continuers, MACE in quitters was significantly reduced after PCI (6.12% vs. 4.81%, P = 0.049), especially recurrent angina (13.97% in continuers vs. 9.84% in quitters, P = 0.027). After adjusting for weight gain and other factors, smoking cessation was independently associated with a lower risk of MACE and recurrent angina (OR = 0.73, P = 0.035). However, weight gain > 1.5 kg (OR = 1.55, P = 0.026) could curtail the benefits from smoking cessation. CONCLUSIONS: Weight gain may reduce the benefits of smoking cessation after PCI with DES implantation. Thus, although smoking cessation is recommended after PCI, weight control should also be highly encouraged for these patients.


Assuntos
Angioplastia Coronária com Balão , Stents Farmacológicos , Abandono do Hábito de Fumar , Aumento de Peso , Idoso , Humanos , Pessoa de Meia-Idade
11.
Zhonghua Nei Ke Za Zhi ; 50(8): 680-2, 2011 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-22093562

RESUMO

OBJECTIVE: To investigate the relationship between smoking and insulin resistance in non-obese male patients with CAD. METHODS: 414 consecutive non-obese male patients with angiographically-documented CAD (luminal diameter narrowing > 50%) were recruited, including 113 nonsmokers and 301 smokers. With 99 mild smokers (< 400 packs/year), 95 medium smokers (400 - 799 packs/year) and 107 heavy smokers (≥ 800 packs/year). Insulin resistance index (IRI) was expressed by homeostasis model assessment for insulin resistance (HOMA-IR) calculated by the formula of [fasting serum glucose (mmol/L) × fasting plasma insulin (mU/L)]/22.5. IRI ≥ 2.69 was defined as insulin resistance, while IRI < 2.69 was insulin sensitive. Fasting glucose, fasting insulin and IRI were recorded and odds ratio for the incidence of insulin resistance was calculated. RESULTS: Fasting glucose was higher in heavy smokers (5.86 mmol/L) than that in nonsmokers (5.51 mmol/L, P = 0.037) and mild smokers (5.33 mmol/L, P = 0.014). Fasting insulin and IRI were also significantly higher in heavy smokers (10.25 mU/L) than those in non-smokers (8.72 mU/L, P = 0.0231, respectively) and mild smokers (8.67 mU/L, P = 0.0231). Compared with nonsmokers, the odds ratio for the incidence of insulin resistance was 1.53 (95%CI 0.55 - 2.94; P = 0.027) in medium smokers and 1.89 (95%CI 0.49 - 3.14; P = 0.018) in heavy smokers. CONCLUSIONS: The relationship between smoking and insulin resistance is highly dose dependent in non-obese male patients with CAD.


Assuntos
Doença da Artéria Coronariana/etiologia , Doença da Artéria Coronariana/metabolismo , Resistência à Insulina , Fumar/efeitos adversos , Idoso , Humanos , Insulina/sangue , Masculino , Pessoa de Meia-Idade
12.
Appl Opt ; 45(7): 1563-8, 2006 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-16539264

RESUMO

We present a design for a biaxial thin-film coated-plate polarizing beam splitter that transmits the p-polarized component of a beam of light without change of direction and reflects the s-polarized component. The beam splitter has a periodic structure and is planned for fabrication by serial bideposition in mutually orthogonal planes. Recent experimental data for form-birefringent silicon is used to establish the feasibility of the design for a beam splitter to be used at 1310 nm and at an angle of 45 degrees in air.

13.
Opt Lett ; 30(19): 2629-31, 2005 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-16208922

RESUMO

The structure of an inorganic chiral medium represented as a stack of identical form-birefringent layers that twist steadily with increasing thickness is perturbed by realigning a fraction of each layer to a fixed direction. Experimental results show that the resulting chiral-birefringent composite medium exhibits Bragg resonance with elliptically polarized light, and simulations indicate that Bragg reflectors can be designed for any polarization including linear.

14.
Opt Express ; 12(16): 3840-7, 2004 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-19483917

RESUMO

The physical vapor deposition process of serial bideposition is adapted to the fabrication of uniaxial optical coatings. During the coating process the vapor impinges at an angle of incidence of about 70 on to the substrate, and a stepwise axial rotation with 90 increments causes a columnar structure to grow normal to the substrate. Symmetry considerations that follow from the choice of 90 for the stepwise increment ensure that the film is achiral and has negligible in-plane linear birefringence. Optical characterization techniques confirm that films of tantalum oxide, titanium oxide and zirconium oxide are positive uniaxial with ne -no in the range 0.10 to 0.14.

15.
Phys Rev Lett ; 91(22): 223903, 2003 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-14683239

RESUMO

We consider the circularly polarized localized modes of chiral photonic structures with combined central twist and isotropic layer defects. The general filter is shown to suffer from anomalous remittance and saturation of linewidth as the thickness of the structure is increased. However, by choosing parameters that phase match the elements of the round-trip matrix of the isotropic layer defect, we demonstrate the existence of supermodes that maintain exceptional purity of polarization state and exponential decrease in linewidth as the thickness is increased.

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