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1.
J Colloid Interface Sci ; 581(Pt A): 135-147, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32771725

RESUMO

HYPOTHESIS: Molecular architecture and composition of amphiphilic bottlebrush copolymers will dictate the dominant interfacial relaxation modes and the corresponding dilatational rheology for adsorbed layers at oil/water interfaces in a way that will correlate with the emulsifying efficiency of different bottlebrush copolymers. EXPERIMENTS: Amphiphilic, xylene-soluble poly(ethylene oxide)-poly(n-butyl acrylate) (PEO-PBA) heterografted bottlebrush copolymers with controlled differences in backbone length, hydrophilicity and arm length were synthesized by atom transfer radical polymerization. Dilatational rheology of adsorbed layers at the xylene/water interface was probed via pendant drop tensiometry by measuring the interfacial stress response to either large-amplitude strain cycling or small-amplitude strain oscillation. The rheological response was recorded as a function of interfacial pressure for adsorbed layers under different compression states. Emulsifying efficiency was determined as the lowest copolymer concentration that yielded water-in-xylene emulsions with at least one-month stability against coalescence. FINDINGS: The more hydrophilic copolymers with longer PEO arms exhibited non-hysteretic stress-strain response curves in large-amplitude strain cycling and a tendency for the modulus to increase with increasing interfacial pressure. These were more efficient emulsifiers than less hydrophilic copolymers that exhibited hysteretic interfacial rheology. Mere existence of significant moduli did not correlate with high emulsifying efficiency, while an increase in modulus with increasing interfacial pressure did so.

2.
ACS Appl Mater Interfaces ; 11(20): 18763-18769, 2019 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-31020827

RESUMO

Atom transfer radical polymerization was utilized to prepare well-defined cylindrical molecular bottlebrushes which were employed as building blocks and transformed into porous nanonetwork-structured carbons (PNSCs) via hypercross-linking chemistry and shape-regulated carbonization. The as-prepared PNSCs exhibited a unique nanomorphology-tunable characteristic by simply varying carbonization conditions. Because of their three-dimensional network nanomorphologies with well-developed hierarchical porous structures and conductive carbon framework, the PNSCs demonstrated excellent electrochemical performance in lithium-sulfur batteries.

3.
Macromol Rapid Commun ; 40(10): e1800876, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30740812

RESUMO

Soft, elastomeric, non-tacky polymer networks are synthesized by reversible deactivation radical polymerization (RDRP). First, the pristine, structurally tailored and engineered macromolecular (STEM) networks are synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization and incorporated an atom transfer radical polymerization (ATRP) inimer into the network. Subsequently, poly(n-butyl acrylate) (PBA) and/or poly(octafluoropentyl acrylate) (POFPA) side chains are grafted from the network by photo-induced ATRP. These low glass transition temperature side chains produced soft materials (E = 104-178 kPa). However, only the POFPA-containing networks are also non-tacky. The fluorine content and material properties are investigated by dynamic mechanical analysis, elemental analysis, spectroscopy, and contact angle measurements.


Assuntos
Acrilatos/química , Materiais Biocompatíveis/química , Polimerização , Polímeros/síntese química , Materiais Biocompatíveis/síntese química , Elasticidade , Estrutura Molecular , Polímeros/química , Engenharia de Proteínas
4.
Biomacromolecules ; 20(1): 27-54, 2019 01 14.
Artigo em Inglês | MEDLINE | ID: mdl-30296828

RESUMO

Molecular bottlebrushes are building blocks for the design of unique polymeric materials whose physical properties are fundamentally governed by their densely grafted structures. Recent developments in the area of reversible deactivation radical polymerization enabled facile and effective control over multiple molecular parameters. Owing to large molecular size, anisotropic conformation, and reduced chain entanglement, molecular bottlebrushes have empowered various applications that are challenging to achieve with linear polymers. In this Review, we focus on determining correlations between brushlike architectures and materials properties.


Assuntos
Técnicas de Química Sintética/métodos , Nanoestruturas/química , Elastômeros/síntese química , Nanoestruturas/ultraestrutura , Polimerização , Tensoativos/síntese química
5.
Acta Ophthalmol ; 95(7): e610-e618, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28653813

RESUMO

PURPOSE: To evaluate the efficacy and safety of eplerenone for chronic nonresolving central serous chorioretinopathy (CSC). METHODS: Prospective, double-blind, randomized placebo-controlled study. Nineteen eyes of 17 patients with persistent subretinal fluid (SRF) due to CSC were enrolled and randomized to receive eplerenone 50 mg/day or placebo for 3 months, followed by a 3-month follow-up. The main outcome measure was change in SRF from baseline to 3 months of treatment. Secondary outcomes included change in SRF at any time-point, complete resolution of SRF, improvement in choroidal thickness and change in best-corrected visual acuity (BCVA). RESULTS: Thirteen eyes were treated with eplerenone and six with placebo. Both groups showed reduction in SRF throughout the treatment period, with a significant reduction at months 1, 3 and 5 only in the treatment group. Twenty-three per cent in the treatment group and 30.8% per cent in the placebo group experienced complete resolution of SRF. A significant improvement in BCVA was noted in the placebo group at 4 months, as well as a significant difference in BCVA between groups at 3 months in favour of the placebo group (p = 0.005). There was no significant difference in choroidal thickness in either group throughout the study period. No adverse events related to eplerenone were noted in the treatment group. CONCLUSION: In this study, eplerenone was not found to be superior to placebo in eyes with chronic CSC.


Assuntos
Coriorretinopatia Serosa Central/tratamento farmacológico , Corioide/patologia , Angiofluoresceinografia/métodos , Espironolactona/análogos & derivados , Tomografia de Coerência Óptica/métodos , Acuidade Visual , Administração Oral , Adolescente , Adulto , Idoso , Coriorretinopatia Serosa Central/diagnóstico , Coriorretinopatia Serosa Central/fisiopatologia , Corioide/efeitos dos fármacos , Doença Crônica , Relação Dose-Resposta a Droga , Método Duplo-Cego , Eplerenona , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Antagonistas de Receptores de Mineralocorticoides/administração & dosagem , Estudos Prospectivos , Espironolactona/administração & dosagem , Fatores de Tempo , Resultado do Tratamento , Adulto Jovem
6.
Int J Ophthalmol ; 6(6): 836-43, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24392334

RESUMO

AIM: To present the outcome of modified grid laser photocoagulation (GLP) in diffuse diabetic macular edema (DDME) in eyes without extrafoveal and/or vitreofoveal traction. METHODS: Inclusion criteria for the retrospective study were DDME eyes of patients with type II diabetes mellitus that had ≥4 months of follow-up following GLP. Only one eye per patient was analyzed. Using 3-D spectral-domain optical coherence tomography (3-D SD-OCT), eyes that had either extrafoveal or vitreofoveal traction, or had been previously treated by an intravitreal medication(s) were excluded. Treated DDME eyes were divided into 4 groups: A) "Classic" DDME that involved the central macula; B) edema did not involve the macular center; C) eyes associated with central epiretinal membrane (ERM); D) DDME that was associated with macular capillary dropout ≥2 disc-diameter (DD). RESULTS: GLP outcome in 35 DDME eyes after 4-24 (mean, 13.1±6.9) months was as follows: Group A) 18 eyes with "classic" DDME. Following one or 2 (mean, 1.2) GLP treatments, best-corrected visual acuity (BCVA) improved by 1-2 Snellen lines in 44.4% (8/18) of eyes, and worsened by 1 line in 11.1% (2/18). Central macular thickness (CMT) improved by 7%-49% (mean, 26.6%) in 77.8% (14/18) of eyes. Causes of CMT worsening (n=4) were commonly explainable, predominantly (n=3) associated with emergence of extrafoveal traction, 5-9 months post-GLP. Group B) GLP(s) in DDME that did not involve the macular center (n=6) resulted in improved BCVA by 1-2 lines in 2 eyes. However, the central macula became involved in the edema process after the GLP in 3 (50%) eyes, associated with an emergence of extrafoveal traction in one of these eyes 4 months following the GLP. Group C) GLP failed in all 5 eyes associated with central ERM. Group D) GLP was of partial benefit in 2 of 6 treated eyes with macular capillary dropout ≥2DD. CONCLUSION: Eyes with DDME that involved the macular center were found to achieve favourable outcomes after GLP(s) during mid-term follow-up, unless complicated pre-GLP or post-GLP by vitreoretinal interface abnormalities, often extrafoveal traction or ERM, or by capillary dropout ≥2DD. Prospective studies with larger cohorts are required.

7.
Invest Ophthalmol Vis Sci ; 52(9): 6414-20, 2011 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-21730347

RESUMO

PURPOSE. To present the vitreoretinal interface in diabetic macular edema (DME) associated with both epiretinal membrane (ERM) and incomplete posterior vitreous detachment (PVD), as detected by spectral-domain optical coherence tomography (SD-OCT). METHODS. In a retrospective study, findings were analyzed in one eye in consecutive patients. Excluded were eyes that had undergone vitreoretinal intervention or that had complete PVD or complete vitreous attachment. RESULTS. Of 44 eyes with DME and ERM, incomplete PVD was apparent in 23 (52.2%) eyes. A hyperreflective unified ERM/posterior vitreous cortex (PViC) membrane, or EVi membrane, was apparent in various sizes in 20 (87.0%) of the 23 eyes. This unified membrane (n = 20) was associated with vitreopapillary adherence in 19 (82.6%) of 23 eyes. Two major OCT presentations (n = 23) were encountered: incomplete vitreopapillary detachment (n = 11; 25% of 44), with attachment to the macular ERM, and posterior vitreous detachment from the macula, associated with vitreopapillary adhesion (n = 10; 22.7%), in four different manifestations. In the remaining two eyes, there was no association between the ERM and the PViC. CONCLUSIONS. In eyes with DME, ERM, and incomplete PVD, the posterior cortical vitreous and ERM appeared as one united EVi membrane in various lengths in most eyes, typically associated with vitreopapillary adhesion. These findings may have clinical importance in the context of epimacular membrane characteristics and its removal in DME.


Assuntos
Retinopatia Diabética/diagnóstico , Membrana Epirretiniana/diagnóstico , Edema Macular/diagnóstico , Tomografia de Coerência Óptica , Descolamento do Vítreo/diagnóstico , Idoso , Idoso de 80 Anos ou mais , Inibidores da Angiogênese/uso terapêutico , Anticorpos Monoclonais/uso terapêutico , Anticorpos Monoclonais Humanizados , Bevacizumab , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Acuidade Visual/fisiologia , Vitrectomia
8.
Open Ophthalmol J ; 5: 35-41, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21643426

RESUMO

PURPOSE: To describe an association between extrafoveal vitreoretinal traction and intractable chronic pseudophakic cystoid macular edema (CME) by the use of optical coherence tomography (OCT). METHODS: In a retrospective case series study, charts and OCT findings of patients who had postoperative recalcitrant pseudophakic CME for at least 6 months and vitreoretinal traction membranes were analyzed. Excluded were eyes that either had another vitreoretinopathy that could affect the analysis or had undergone an intravitreal intervention. RESULTS: Three eyes (three patients) with macular edema following uneventful cataract surgery were detected to be associated with multifocal extrafoveal vitreoretinal traction sites in each. Retinal edema that was underlying each of the traction sites in all eyes was in continuum in at least one site per eye with the central macular edema, thus manifesting as diffuse macular edema. CONCLUSION: Chronic pseudophakic macular edema may be related to extrafoveal vitreoretinal traction.

9.
Graefes Arch Clin Exp Ophthalmol ; 249(6): 811-20, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21472465

RESUMO

BACKGROUND: To present extrafoveal vitreous traction membranes, and their prevalence and association with diffuse macular oedema in eyes with retinal vein occlusion (RVO), using 3-D spectral-domain optical coherence tomography (SD-OCT). METHODS: In a retrospective institutional observational study, charts and qualified SD-OCT findings of consecutive patients with either central retinal vein occlusion (CRVO) or branch retinal vein occlusion (BRVO) associated with macular oedema were analyzed. Exclusion criteria covered eyes that had: 1) another retinopathy that could affect the data analysis, 2) vitreoretinal adherence without signs of retinal traction, 3) undergone vitreoretinal surgery, or 4) been treated by intravitreal administration of medication(s). An age-matched control group (n = 72) afforded the normal central subfield thickness. RESULTS: Twenty-six eyes (of 26 patients) with either CRVO (n = 12) or BRVO (n = 14) were analyzed. Four eyes were excluded because they had a lack of macular oedema (n = 2), had an earlier pars plana vitrectomy (n = 1), or had previous treatment by intravitreal bevacizumab (n = 1). Of the 22 remaining eyes, both the SD-OCT B-mode video clip and the 3-D image reconstruction enabled a detection of extrafoveal traction membranes, either unifocally or multifocally, in nine eyes: four (of 11; 36.4 %) in CRVO, and five eyes (of 11; 45.5%) in BRVO. The retinal oedema in these nine eyes, which underlined at least one of the traction sites per eye, and the accompanied subretinal fluid in four of these nine eyes, were in continuum in each eye with the diffuse macular oedema and serous macular detachment respectively. During follow-up, a spontaneous release of a traction membrane coupled with resolution of the macular oedema occurred in one eye with BRVO. Of the four eyes that were excluded, two eyes had extrafoveal vitreous traction membranes. CONCLUSIONS: The SD-OCT B-mode video clip and its 3-D image reconstruction enabled relatively frequent detection of extrafoveal vitreous traction membranes in RVO and their association with diffuse macula oedema and macular detachment. A larger cohort is required to validate these findings and to compare the efficacy of early release of such traction membranes, either surgically or possibly by pharmacologic vitreolysis, with the current therapeutic modalities.


Assuntos
Oftalmopatias/diagnóstico , Doenças Retinianas/diagnóstico , Oclusão da Veia Retiniana/diagnóstico , Aderências Teciduais/diagnóstico , Tomografia de Coerência Óptica , Corpo Vítreo/patologia , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Imageamento Tridimensional , Edema Macular/diagnóstico , Edema Macular/etiologia , Masculino , Pessoa de Meia-Idade , Oclusão da Veia Retiniana/etiologia , Estudos Retrospectivos , Aderências Teciduais/complicações , Campos Visuais
10.
J Pediatr Ophthalmol Strabismus ; 48(3): 174-81, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-20669879

RESUMO

PURPOSE: The authors examined the peripapillary (3.4-mm diameter) retinal nerve fiber layer thickness (RNFL thickness) as depicted by optical coherence tomography (OCT) in young patients with pseudopapilledema or papilledema. METHODS: In 17 consecutive patients (6 to 20 years old) with bilateral newly diagnosed papilledema or pseudopapilledema, the eye with the thicker mean global RNFL per patient was analyzed. Excluded were patients in whom cerebrospinal fluid opening pressure was between 190 and 250 mm H(2)O ("gray zone"). RNFL thickness was compared in eyes with papilledema and pseudopapilledema using the Mann-Whitney U test. RESULTS: Papilledema was clinically diagnosed in 9 patients and pseudopapilledema in 6 patients; 2 patients were excluded. Median RNFL thickness in the eyes with papilledema was greater than that of both eyes with pseudopapilledema and controls at all 12 clock hours. In all 9 patients with papilledema, RNFL was thickened contiguously for 8 to 12 clock hours above the upper 95% confidence interval limit of normal. CONCLUSION: The peripapillary RNFL thickness as depicted by OCT was found to be a reliable adjunctive tool in the differentiation of newly diagnosed papilledema and pseudopapilledema in young patients. Larger cohorts are required to confirm these observations and conclusion.


Assuntos
Técnicas de Diagnóstico Oftalmológico , Fibras Nervosas/patologia , Disco Óptico/patologia , Papiledema/diagnóstico , Células Ganglionares da Retina/patologia , Tomografia de Coerência Óptica , Adolescente , Criança , Diagnóstico Diferencial , Oftalmopatias Hereditárias/diagnóstico , Oftalmopatias Hereditárias/etiologia , Feminino , Humanos , Masculino , Doenças do Nervo Óptico/diagnóstico , Doenças do Nervo Óptico/etiologia , Papiledema/etiologia , Estudos Retrospectivos , Acuidade Visual/fisiologia , Adulto Jovem
11.
Eur J Ophthalmol ; 20(4): 733-9, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20099242

RESUMO

PURPOSE: To present patients with extrafoveal vitreous traction associated with diffuse macular edema secondary to branch retinal vein occlusion (BRVO). METHODS: A retrospective study on consecutive patients with BRVO using optical coherence tomography (OCT)-2000 is reported. Excluded were patients with eyes with other retinopathies that could affect analysis and eyes following pars plana vitrectomy (PPV). A control group of 30 age-matched patients allowed for normal OCT 6-mm macular maps. RESULTS: Vitreous traction was detected in 4 of 17 eyes (17 patients, 23.5%). The traction was located extrafoveally in each of the 4 eyes. In one eye there was a simultaneous central macular traction. Only the manually controlled OCT-Line group program, but not the central automatic 6-radial lines program, confirmed vitreous traction in each case. Retinal edema (n = 4) and serous retinal detachment (n = 2) underlining the traction sites were in continuum with the central macula in 3 eyes, presenting either as diffuse macular edema or combined with serous macular detachment, respectively. In one eye the edema subsided after PPV, and visual acuity stabilized during 7 postoperative months of follow-up. Macular thickness and visual acuity of another eye improved temporarily in repeated conventional treatments after PPV was discarded, but its fovea markedly atrophied 12 months later. CONCLUSIONS: Extrafoveal vitreous traction may be apparent following BRVO. Further studies are required to assess whether such traction membranes may play a role in the persistence of diffuse macular edema.


Assuntos
Oclusão da Veia Retiniana/complicações , Vitrectomia/métodos , Descolamento do Vítreo/etiologia , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Oclusão da Veia Retiniana/diagnóstico , Oclusão da Veia Retiniana/cirurgia , Estudos Retrospectivos , Tomografia de Coerência Óptica , Acuidade Visual , Descolamento do Vítreo/diagnóstico , Descolamento do Vítreo/cirurgia
12.
Int J Ophthalmol ; 3(4): 321-5, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-22553583

RESUMO

AIM: To describe an association between extrafoveal vitreoretinal traction and chronic macular edema, either diffuse (DiME) or cystoid (CME), by the use of optical coherence tomography (OCT). METHODS: Charts and OCT findings of two patients with persistent DiME or persistent DiME accompanied by CME, both associated with extrafoveal vitreous traction membranes were analyzed. Excluded were eyes that either had another vitreoretinopathy that could affect the analysis, had undergone pars plana vitrectomy or that had been treated by intravitreal medications. An age-matched normal control group for OCT (n=12) allowed for the quantification of the normal macular thicknesses. RESULTS: One patient (one eye) following perforating ocular injury and one patient (one eye) of idiopathic origin, both with chronic macular edema refractive to conventional treatment, were found to be associated with extrafoveal vitreoretinal traction in each eye. Retinal edema that was underlying the traction site in each eye was in continuum with the central macular edema, thus manifesting as diffuse macular edema. The automatic central 6-radial lines program in the OCT enabled the detection of the traction site in one eye, while in the other eye the diagnosis was achieved only with the additional use of the Line group program. CONCLUSION: Chronic diffuse macular edema might be related to extrafoveal vitreoretinal traction. Careful search with the diverse OCT programs should be made in order to detect extrafoveal traction sites. Further studies and a larger cohort are required to compare the efficacy of early vitrectomy or pharmacologic vitreolysis versus the current therapeutic approaches in these situations.

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