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1.
Chemistry ; 30(20): e202400029, 2024 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-38287711

RESUMO

Anion-exchange membrane fuel cells and water electrolyzers have garnered significant attention in past years due to their potential role in sustainable and affordable energy conversion and storage. However, the chemical stability of the polymeric anion-exchange membranes (AEMs), the key component in these devices, currently limits their lifespan. Recently, metallopolymers have been proposed as chemically stable alternatives to organic cations, using metal centers as ion transporters. In metallopolymer AEMs, various properties such as alkaline stability, water uptake, flexibility, and performance, are determined by both the metal complex and polymer backbone. Herein we present a systematic study investigating the influence of the polymer backbone chemistry on some of these properties, focusing on the alkaline stability of low-oxophilicity gold metallopolymers. Despite the use of a common N-heterocyclic carbene ligand, upon gold metalation using the same reaction conditions, different polymer backbones end up forming different gold complexes. These findings suggest that polymer chemistry affects the metalation reaction in addition to the other properties relevant to AEM performance.

2.
Chemistry ; 28(7): e202103744, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34878688

RESUMO

Anion-exchange membrane fuel cells (AEMFCs) are promising energy conversion devices due to their high efficiency. Nonetheless, AEMFC operation time is currently limited by the low chemical stability of their polymeric anion-exchange membranes. In recent years, metallopolymers, where the metal centers assume the ion transport function, have been proposed as a chemically stable alternative. Here we present a systematic study using a polymer backbone with side-chain N-heterocyclic carbene (NHC) ligands complexed to various metals with low oxophilicity, such as copper, zinc, nickel, and gold. The golden metallopolymer, using the metal with the lowest oxophilicity, demonstrates exceptional alkaline stability, far superior to state-of-the-art quaternary ammonium cations, as well as good in situ AEMFC results. These results demonstrate that judiciously designed metallopolymers may be superior to purely organic membranes and provides a scientific base for further developments in the field.

3.
Retina ; 42(7): 1356-1363, 2022 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-35723923

RESUMO

PURPOSE: To study the utility of MultiColor confocal scanning laser ophthalmoscope imaging (MCI) in identifying the morphology of uveitic lesions compared with conventional color fundus photography (CFP) in patients with posterior uveitis. METHODS: In this prospective observational study, subjects with posterior uveitis underwent MCI and CFP. The images obtained by the two modalities were analyzed by two independent reviewers for vitreoretinal surface abnormalities, retinal fluid and hemorrhages, and depth/location of lesions. These findings were compared with the clinical findings and other imaging techniques. RESULTS: Sixty-nine eyes of 43 patients (25 men) with mean age of 33.5 ± 13.9 years were studied. MultiColor imaging had better sensitivity and specificity in detecting vitreoretinal interface abnormalities, such as epiretinal membrane and inner retinal striae, compared with CFP. MultiColor imaging failed to detect retinochoroiditis lesions in 5 of 6 eyes (83%) and choroiditis in 9 46 eyes (20%), which were detected on CFP and clinical examination. Also, MCI showed a high false-positive rate of 34% in detecting intraretinal hemorrhages. CONCLUSION: Retinochoroidal lesions in posterior uveitis may be poorly identified on MCI compared with CFP and clinical examination. One must exercise caution in commenting on disease morphology based on MCI alone.


Assuntos
Tomografia de Coerência Óptica , Uveíte Posterior , Adulto , Angiofluoresceinografia/métodos , Fundo de Olho , Humanos , Lasers , Masculino , Pessoa de Meia-Idade , Oftalmoscópios , Oftalmoscopia/métodos , Estudos Retrospectivos , Tomografia de Coerência Óptica/métodos , Uveíte Posterior/diagnóstico , Adulto Jovem
4.
Macromol Rapid Commun ; 42(16): e2100238, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34173300

RESUMO

Long-term stability is a key requirement for anion-exchange membranes (AEMs) for alkaline fuel cells and electrolyzers that is yet to be fulfilled. Different cationic chemistries are being exploited to reach such a goal, and metallopolymers present the unique advantage of chemical stability towards strong nucleophiles as compared to organic cations. Yet, the few metallopolymers tested in strongly alkaline conditions or even in fuel cells still degrade. Therefore, fundamental studies can be advantageous in directing future developments towards this goal. Here, a systematic study of the effect of ligand valency is presented, using nickel-based metallopolymers on polynorbornene backbones, functionalized with multidentate pyridine ligands. Metallopolymers using a single ligand type as well as all the possible mixtures are prepared and their relative stability towards aggressive alkaline conditions compared. Metallopolymer in which nickel ions are hexacoordinated with two tridentate ligands demonstrates superior stability. More importantly, by comparing all the metallopolymers' stability, the reason behind such relative stability provides design parameters for novel metallopolymer AEMs.


Assuntos
Níquel , Ânions , Cátions , Ligantes
5.
Retina ; 41(4): 793-803, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32833411

RESUMO

PURPOSE: To analyze and describe serial follow-up of choriocapillaris alterations in tubercular serpiginouslike choroiditis (SLC) using optical coherence tomography angiography (OCTA) and to compare it with multimodal imaging. METHODS: In this prospective cohort study, patients with active tubercular SLC underwent OCTA using Optovue RTVue XR Avanti and other imaging techniques including enhanced-depth imaging OCT (EDI-OCT) (Heidelberg Spectralis; Heidelberg Engineering, Heidelberg, Germany), fundus autofluorescence, fluorescein angiography, and indocyanine green angiography. Serial imaging was performed for a total follow-up of 3 months. Choriocapillaris alterations at the site of lesions were analyzed on OCTA imaging, and their mean lesion areas were calculated. RESULTS: Twenty-six eyes (26 patients; 20 males; mean age: 32.68 ± 10.56 years) were included. Fourteen eyes had active multifocal lesions (n = 39), whereas 12 eyes had active placoid lesions (n = 12). At baseline, OCTA showed hyporeflective flow deficit lesions corresponding to the hypofluorescent lesions on indocyanine green angiography in all eyes. In the multifocal type of SLC, the mean lesion area decreased in all eyes compared with baseline, and lesions with a lesion area less than 0.1 mm2 on OCTA showed near-complete resolution with minimal choriocapillaris atrophy. In comparison, all eyes with a placoid type of SLC showed no significant reduction in the lesion area and showed extensive choriocapillaris atrophy. CONCLUSION: Optical coherence tomography angiography has the unique ability to demonstrate pathological flow impairment at the level of choriocapillaris in active tubercular SLC. Serial OCTA analysis reveals that large tubercular SLC lesions result in choriocapillaris atrophy as the lesions heal, whereas smaller multifocal lesions show resolution of choriocapillaris hypoperfusion with minimal atrophy.


Assuntos
Corioide/irrigação sanguínea , Corioidite/diagnóstico por imagem , Tuberculose Ocular/diagnóstico por imagem , Adulto , Antituberculosos/uso terapêutico , Corioidite/tratamento farmacológico , Corioidite/fisiopatologia , Corantes/administração & dosagem , Feminino , Angiofluoresceinografia , Seguimentos , Humanos , Aumento da Imagem , Verde de Indocianina/administração & dosagem , Masculino , Pessoa de Meia-Idade , Imagem Multimodal , Estudos Prospectivos , Tomografia de Coerência Óptica , Tuberculose Ocular/tratamento farmacológico , Tuberculose Ocular/fisiopatologia , Acuidade Visual/fisiologia , Adulto Jovem
6.
Retina ; 41(4): 774-783, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32833410

RESUMO

PURPOSE: To report the frequency, optical coherence tomography (OCT) findings, and visual and anatomic outcomes of patients with acute Vogt-Koyanagi-Harada disease presenting with the bacillary layer detachment (BLD) (intraretinal split at the photoreceptor inner segment myoid). METHODS: This was a retrospective analysis of a consecutive series of patients with Vogt-Koyanagi-Harada disease having a minimum follow-up of 6 months. All patients had swept-source OCT, fluorescein angiography, and indocyanine green angiography performed at baseline. The characteristics of serial swept-source OCT were recorded and analyzed. RESULTS: Sixty-two subjects (42 women; age: 34.2 ± 12 years) with Vogt-Koyanagi-Harada disease were included. 118 eyes (95.2%) had serous retinal detachment at presentation. 112 eyes (94.9%) showed the BLD at baseline. In 8 of 112 (7.1%) eyes with the BLD, the external limiting membrane at the anterior aspect of the BLD showed focal discontinuity. The interdigitation zone at the base of the BLD showed discontinuity in 53 of 112 (47.3%) eyes with the BLD. The ellipsoid zone could not be identified as a separate hyperreflective line at the base of the BLD in 102 of 112 eyes (91.1%). Bacillary layer detachments resolved within 3.4 ± 1.3 days after intravenous methylprednisolone therapy with improvement in the best-corrected visual acuity from 0.96 to 0.4 logarithm of the minimum angle of resolution (20/184 Snellen's equivalent) (P < 0.001). Resolution of serous retinal detachment was observed after 5.9 ± 2.6 days. CONCLUSION: In eyes with acute Vogt-Koyanagi-Harada disease, the BLD is a common finding and represents a split in the photoreceptor layer at the inner segment myoid and can be differentiated from serous retinal detachment using swept-source OCT. In addition, resolution of the BLD and photoreceptor recovery can be evaluated using serial swept-source OCT.


Assuntos
Descolamento Retiniano/etiologia , Síndrome Uveomeningoencefálica/complicações , Doença Aguda , Adulto , Feminino , Angiofluoresceinografia , Seguimentos , Glucocorticoides/uso terapêutico , Humanos , Imunossupressores/uso terapêutico , Masculino , Metilprednisolona/uso terapêutico , Pessoa de Meia-Idade , Descolamento Retiniano/diagnóstico por imagem , Descolamento Retiniano/tratamento farmacológico , Estudos Retrospectivos , Tomografia de Coerência Óptica , Síndrome Uveomeningoencefálica/diagnóstico por imagem , Síndrome Uveomeningoencefálica/tratamento farmacológico , Acuidade Visual/fisiologia , Adulto Jovem
7.
Mol Biol Rep ; 47(4): 2447-2457, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32124167

RESUMO

The genus Rhododendron, known for large impressive flowers is widely distributed throughout the world. Rhododendrons have limited genetic information, despite of comprising high species diversity, morphological overlap and weak genetic barrier. In present study, expressed sequence tag (EST) data from Rhododendron catawbiense Michx (Subgenus Hymenanthes, Section Ponticum) and Rhododendron mucronatum var. ripense (Makino) E.H. Wilson (Subgenus Tsutsusi, Section Tsutsusi) were utilized for mining and identification of the SSRs for genetic diversity analysis of R. arboreum Smith (Subgenus Tsutsusi, Section Tsutsusi). A total of 249 SSRs were developed from 1767 contigs. Di-nucleotide was found to be most abundant repeat followed by tri- and tetra-nucleotide repeats. The motif AG/CT was most common di-nucleotide motif (31.73%), whereas, AAC/GTT (8.43%), ACG/CGT (8.03%), AAG/CTT (7.23%) and AGG/CCT (6.43%) were most abundant tri-nucleotide repeat motif. Among these SSRs, 168 sequences were only fit into the criteria to design flanking primer pairs. A total of 30 randomly selected primer pairs were utilized for validation and genetic diversity study in 36 genotypes of R. arboreum collected from western Himalayan region. In aggregate, 26 SSR markers (86.66%) produced good and repeatable amplifications. Expected heterozygosity (HE) ranged from 0.322 to 0.841 and observed heterozygosity (HO) ranged from 0.327 to 1.000 and PIC value ranged from 0.008 to 0.786. These primers were able to distinguish the geographic differences of occurrence based on cluster analysis. These developed EST-SSRs can be useful in future population genetics analysis and micro-evolutionary studies in Rhododendron species.


Assuntos
Repetições de Microssatélites/genética , Rhododendron/genética , DNA de Plantas/genética , Etiquetas de Sequências Expressas/metabolismo , Marcadores Genéticos/genética , Variação Genética/genética , Genoma de Planta/genética , Genótipo , Motivos de Nucleotídeos/genética , Polimorfismo Genético/genética , Análise de Sequência de DNA/métodos
8.
Retina ; 39(8): 1595-1606, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29689028

RESUMO

PURPOSE: To study optical coherence tomography angiography (OCTA) and multimodal imaging features of Type 1 inflammatory choroidal neovascularization (CNV) in tubercular serpiginous-like choroiditis and response to anti-vascular endothelial growth factor therapy. METHODS: In this study, multimodal imaging was performed using OCTA, enhanced-depth imaging optical coherence tomography, fluorescein angiography, and indocyanine green angiography. Correlation of OCTA with other imaging modalities in the detection of CNV was performed. The changes in CNV configuration after anti-vascular endothelial growth factor therapy were assessed. RESULTS: In this study, nine eyes (8 patients; 5 females; mean age: 32.5 ± 11.57 years) with diagnosis of tubercular serpiginous-like choroiditis were included. All the eyes had presence of low-lying pigment epithelial detachments on enhanced-depth imaging optical coherence tomography. Using OCTA, it was possible to detect Type 1 CNV in all eyes. Type 1 CNV networks comprised fine anastomotic network of vessels, some of which had a hairpin loop configuration. After anti-vascular endothelial growth factor therapy, there was a decrease in branching and anastomosis. The visual acuity significantly improved from 0.49 ± 0.26 (20/60 Snellen equivalent) at baseline to 0.26 ± 0.17 (20/36 Snellen equivalent) (P = 0.03) in all eyes. CONCLUSION: Type 1 CNV can occur among patients with tubercular serpiginous-like choroiditis, leading to significant visual loss even in the healed stages of the disease. Optical coherence tomography angiography can help in the detection of Type 1 CNV where conventional multimodal imaging, including fluorescein angiography and OCT, fails to make a definitive diagnosis and thereby guide the initiation of anti-vascular endothelial growth factor therapy.


Assuntos
Neovascularização de Coroide/diagnóstico , Corioidite/diagnóstico , Tuberculose Ocular/diagnóstico , Adolescente , Adulto , Inibidores da Angiogênese/uso terapêutico , Corioide/irrigação sanguínea , Corioidite/microbiologia , Corantes/administração & dosagem , Feminino , Angiofluoresceinografia , Humanos , Verde de Indocianina/administração & dosagem , Masculino , Pessoa de Meia-Idade , Imagem Multimodal , Tomografia de Coerência Óptica , Tuberculose Ocular/microbiologia , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Acuidade Visual , Adulto Jovem
9.
Retina ; 39(11): 2167-2177, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30080742

RESUMO

PURPOSE: Patients with macula-off rhegmatogenous retinal detachments (RRDs) may have suboptimal visual recovery, despite successful reattachment due to various reasons. This study was performed to evaluate the retinal microvasculature in subjects undergoing surgery for RRD using optical coherence tomography angiography. METHODS: In this case-control study, the analysis of optical coherence tomography angiography findings of 19 eyes of 19 patients (15 men) who underwent RRD surgery at a tertiary institute were compared with 19 eyes of 19 age- and sex-matched healthy subjects with no known ocular disease. 3 × 3-mm optical coherence tomography angiography scans were obtained at 3 months postoperatively and analyzed. Optical coherence tomography angiography images of patients with RRD and control subjects were analyzed for capillary density index and fractal dimensions. RESULTS: Mean age of the patients was 40.21 years, and the mean age of controls was 43.73 years. Eight eyes underwent scleral buckling alone, and 11 eyes underwent primary vitrectomy with gas tamponade (C3F8 gas) for macula-off RRD. None of the eyes had redetachment during the follow-up at 3 months. Mean capillary density index among patients was 33.28% ± 0.99% and 34.06% ± 2.22% in the superficial and deep retinal plexuses, respectively, compared with 36.11% ± 1.29% and 37.52% ± 1.24% among controls (P < 0.001). The mean fractal dimension was lower among subjects compared with controls (1.46 vs. 1.61 in the superficial plexus, P < 0.001; 1.58 vs. 1.64 in the deep plexus, P < 0.001). CONCLUSION: Optical coherence tomography angiography demonstrates significant reduction in mean capillary density index and fractal dimension in patients after surgery for RRD in our patients. Thus, reduction in vascular perfusion and branching pattern identified using novel analysis techniques on optical coherence tomography angiography images may provide an insight into the reasons for suboptimal visual gain after RRD surgery.


Assuntos
Angiofluoresceinografia/métodos , Macula Lutea/patologia , Descolamento Retiniano/cirurgia , Recurvamento da Esclera/métodos , Tomografia de Coerência Óptica/métodos , Acuidade Visual , Vitrectomia/métodos , Adulto , Estudos de Casos e Controles , Tamponamento Interno/métodos , Feminino , Seguimentos , Fundo de Olho , Humanos , Macula Lutea/cirurgia , Masculino , Estudos Prospectivos , Descolamento Retiniano/diagnóstico
10.
Retina ; 39(8): 1623-1630, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29697588

RESUMO

PURPOSE: Tubercular retinal vasculitis (TRV) is a heterogeneous disease that can be difficult to manage because of nonspecific presentation and limitations of confirmatory tests for tuberculosis. This is a big data analysis on phenotypes and treatment outcomes for TRV. METHODS: Multicentre retrospective study of patients with TRV between January 2004 and December 2014 and a minimum follow-up of 1 year. RESULTS: Two hundred and fifty-one patients with TRV with a mean age of 38.9 ± 14.4 years (range, 9-86 years) were included. The patients were predominantly males (n = 167/251; 66.5%) of Asian ethnicity (n = 174/246; 70.7%), and geographical origin (n = 137/251; 54.6%). Most patients had features of occlusive type of RV (n = 113/185; 61.1%) except Caucasians (n = 11; 28.2%). There was no significant difference in treatment failure whether patients received antitubercular therapy (ATT) (P = 0.29), although treatment failure was less frequent in patients who received ATT (13.6%; n = 31/228) compared with those who did not (21.7%, n = 5/23). Less treatment failures were observed in patients with occlusive type RV who received ATT; however, this was not significant on survival analysis (P = 0.09). Treatment with ATT was associated with higher failure rates in patients of Hispanic and African American race and those with TRV associated with panuveitis (compared with posterior uveitis). CONCLUSION: In this multinational study of TRV, there was no significant therapeutic effect of ATT. However, a definitive conclusion about the role of ATT could not be made because of a few patients who did not receive ATT. Because this is a retrospective study with a limited 1-year follow-up, the effect of ATT may have been overestimated (or underestimated) in the duration of follow-up.


Assuntos
Vasculite Retiniana/diagnóstico , Tuberculose Ocular/diagnóstico , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Antituberculosos/uso terapêutico , Criança , Quimioterapia Combinada , Feminino , Humanos , Imunossupressores/uso terapêutico , Masculino , Pessoa de Meia-Idade , Recidiva , Vasculite Retiniana/tratamento farmacológico , Vasculite Retiniana/microbiologia , Estudos Retrospectivos , Resultado do Tratamento , Tuberculose Ocular/tratamento farmacológico , Tuberculose Ocular/microbiologia , Adulto Jovem
11.
Clin Exp Ophthalmol ; 46(1): 62-74, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28557287

RESUMO

IMPORTANCE: In a subset of patients with retinal vasculitis, there is occlusion of blood flow through the retinal vessels. These eyes are at high risk of sight-threatening complications. BACKGROUND: To characterize epidemiology, clinical course, treatment and outcomes of occlusive retinal vasculitis (ORV). DESIGN: Retrospective study PARTICIPANTS: Seventy-seven uveitis patients with ORV at two large tertiary-care institutions (the USA and India). METHODS: Out of 2438 patients screened, 346 patients were diagnosed with retinal vasculitis of which 77 patients (96 eyes) were diagnosed with ORV. Patients with ORV (capillary, arteriolar and/or venular) were further analysed. Diagnostic criteria for occlusive vasculitis included (i) absence of blood flow in vessels (arterioles, venules and/or capillaries), (ii) capillary non-perfusion areas and/or arteriolar-venous anastomosis and (iii) intraretinal haemorrhages, cotton-wool spots or vitreous haemorrhage. MAIN OUTCOME MEASURES: Best-corrected visual acuity, treatment and complications. RESULTS: The mean age was 32.09 ± 13.51 years. Most common aetiologies were tuberculosis and Adamantiades-Behçet's disease in India and systemic lupus erythematosus in the USA. Best-corrected visual acuity improved from 0.38 ± 0.30 logMAR (20/48 Snellen equivalent) (baseline) to 0.25 ± 0.30 (20/35 Snellen equivalent) at final visit (P < 0.0001). Vitreous haemorrhage was seen in 31.08% eyes. Pars plana vitrectomy was performed in 12.16% eyes. Therapy with systemic steroids was required in 78.48% patients. In addition, 46.75% patients required immunomodulators and/or biologics. CONCLUSIONS: Occlusive retinal vasculitis is caused by heterogeneous group of uveitides depending upon the geographic location. It is imperative to identify eyes with ORV as they are predisposed to complications requiring aggressive therapy.


Assuntos
Angiofluoresceinografia/métodos , Vasculite Retiniana/epidemiologia , Centros de Atenção Terciária , Acuidade Visual , Adolescente , Adulto , Idoso , Criança , Feminino , Seguimentos , Fundo de Olho , Humanos , Incidência , Índia/epidemiologia , Masculino , Pessoa de Meia-Idade , Vasculite Retiniana/diagnóstico , Vasculite Retiniana/fisiopatologia , Estudos Retrospectivos , Adulto Jovem
13.
Retina ; 37(9): 1647-1659, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27930457

RESUMO

PURPOSE: To analyze and describe the imaging characteristics of tubercular serpiginous-like choroiditis using optical coherence tomography angiography (OCTA) and to compare these findings with multimodal imaging. METHODS: In this prospective cross-sectional study, multimodal imaging was performed in subjects with tubercular serpiginous-like choroiditis using OCTA (Optovue RTVue XR Avanti), enhanced-depth imaging OCT (Heidelberg Spectralis), fundus autofluorescence, fluorescein angiography, and indocyanine green angiography. Distinct morphologic features of the retinochoroidal vasculature at the sites of choroiditis lesions were analyzed on OCTA imaging. Multimodal imaging analysis was performed to study the changes observed on OCTA. RESULTS: Eighteen eyes (18 subjects, 16 males) were included in the study. The en face OCTA images demonstrated discrete areas of flow void beneath the retinal pigment epithelium-Bruch membrane layer suggestive of choriocapillaris hypoperfusion that corresponded well with indocyanine green angiography, especially in the chronic phase. Additional information such as areas of preserved choriocapillaris, vascular tufts, and tangled vessels were observed using OCTA among lesions in advanced stages of healing. Compared with indocyanine green angiography, the areas of choriocapillaris atrophy appeared better defined on OCTA and correlated well with enhanced-depth imaging OCT. CONCLUSION: The OCTA images provide high-resolution structural information of the retinochoroidal vasculature in tubercular serpiginous-like choroiditis. Morphologic information obtained from OCTA images correlates well with and supplements other imaging techniques such as indocyanine green angiography and enhanced-depth imaging OCT.


Assuntos
Corioidite/diagnóstico por imagem , Angiofluoresceinografia/métodos , Tomografia de Coerência Óptica/métodos , Tuberculose Ocular/diagnóstico por imagem , Adolescente , Adulto , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Imagem Multimodal , Estudos Prospectivos , Tuberculose Ocular/complicações , Adulto Jovem
15.
Heliyon ; 10(11): e31702, 2024 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-38867945

RESUMO

The release of organic pollutants and dyes into the environment by industries has had profound and harmful effects on both humans and ecosystems. Graphene oxide (GO) and its reduced form have been investigated for their effectiveness in removing pollutant dyes. GO nano-powder was synthesized using an improved version of Hummer's method and subsequently thermally reduced at various temperatures, including 125, 150, 175, and 200 °C, under vacuum conditions. In the X-ray diffraction spectra, an intense (001) diffraction peak was initially observed at 9.136° (2θ) for pristine GO. This peak gradually shifted towards higher angles as the reduction process took place and eventually disappeared when the GO was reduced at 200 °C. The intensity ratio of the D and G bands (ID/IG ratio) for GO nano-powder in the Raman spectra decreased from 0.94 to 0.76 due to the reduction process. The FTIR spectra of GO and reduced graphene oxide (rGO) also illustrated the reduction process. The bandgap of pristine GO significantly decreased from 2.31 to 0.73 eV, as determined by ultraviolet-visible (UV-Vis) diffuse reflectance spectrophotometry during the reduction process. The surface area and pore volume of both pristine GO and rGO-150 were determined using the BET (Brunauer-Emmett-Teller) and BJH (Barrett-Joyner-Halenda) methods. The results indicated an increase in the BET surface area from 6.61 to 7.86 m2/g and a corresponding enhancement in pore volume from 0.118 to 0.128 cc/g after reduction. The adsorption and photocatalytic degradation behavior of pristine GO and reduced graphene oxides (rGOs) were examined using methylene blue dye. The pristine GO demonstrated impressive adsorption capability, effectively removing the dye by 85.78 % within just 15 min and achieving nearly 97 % removal after 4 h. In contrast, the highest photocatalytic degradation of methylene blue, about 47.58 %, was attained for the rGO sample reduced at 150 °C under the illumination of visible light.

17.
Ocul Immunol Inflamm ; 31(1): 48-55, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34648411

RESUMO

AIM: To analyze the structural features and therapeutic response in clinical and subclinical inflammatory choroidal neovascularization (i-CNV) detected inside subretinal hyperreflective material (SHRM) using swept-source optical coherence tomography (SS-OCT) and SS-OCT angiography (SS-OCTA). METHODS: In this prospective interventional study, subjects with quiescent posterior uveitis presenting with SHRM on SS-OCT and CNV network on SS-OCTA were included. Subjects with intraretinal fluid/subretinal fluid (IRF/SRF) received intravitreal antivascular endothelial growth factor (anti-VEGF) injections, while those with no IRF/SRF either received treatment or observation for 6 months until they developed IRF/SRF or decrease in best-corrected visual acuity (BCVA)/metamorphopsia. Serial comparisons included SHRM width and height and intrinsic flow signal on OCTA. RESULTS: 28 eyes of 22 subjects (12 males; mean age: 29.52 ± 12.56 years) were evaluated. Subjects with IRF/SRF at baseline (n = 6 eyes; termed as exudative iCNVs) receiving treatment showed significant improvement in BCVA (p = .017), SHRM width/height and flow signal (p < .05). Among eyes with no IRF/SRF (n = 22; termed as non-exudative iCNVs), 7 received treatment and showed significant improvement in SHRM parameters and BCVA (p < .05). 4/15(26.67%) eyes that received no treatment developed IRF/SRF upon 6-month follow-up. CONCLUSION: SHRM may act as a useful biomarker to monitor activity and response to therapy in eyes with iCNV.


Assuntos
Neovascularização de Coroide , Adolescente , Adulto , Humanos , Masculino , Adulto Jovem , Inibidores da Angiogênese/uso terapêutico , Biomarcadores , Neovascularização de Coroide/diagnóstico , Neovascularização de Coroide/tratamento farmacológico , Angiofluoresceinografia/métodos , Injeções Intravítreas , Estudos Prospectivos , Líquido Sub-Retiniano , Tomografia de Coerência Óptica/métodos , Feminino
18.
Ocul Immunol Inflamm ; 30(2): 397-401, 2022 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-32976040

RESUMO

PURPOSE: To report a patient with submacular hemorrhage due to retinal angiomatous proliferation (RAP) in tubercular retinal vasculitis (TRV). METHODS: Case report. RESULTS: We report a 33-year-old Asian Indian patient of TRV presenting with capillary non-perfusion areas, submacular hemorrhage and venous loops. The patient presented with sudden onset decrease in vision in the right eye. Multimodal imaging revealed presence of retinal vascular anastomosis and stage 2 RAP. Systemic examination was within normal limits. Laboratory evaluation revealed positive Mantoux and interferon gamma release assay. He underwent right eye intravitreal injection of recombinant tissue plasminogen activator (12.5µg/0.1ml) with 100% sulphur hexafluoride (SF6) tamponade. The patient had successful displacement of the submacular hemorrhage with some improvement in visual acuity. CONCLUSION: This case highlights that rare vascular alterations such as RAP can develop in subjects with ocular tuberculosis.


Assuntos
Degeneração Macular , Vasculite Retiniana , Adulto , Proliferação de Células , Fibrinolíticos/uso terapêutico , Angiofluoresceinografia , Humanos , Masculino , Hemorragia Retiniana/diagnóstico , Hemorragia Retiniana/tratamento farmacológico , Hemorragia Retiniana/etiologia , Vasculite Retiniana/complicações , Vasculite Retiniana/diagnóstico , Vasculite Retiniana/tratamento farmacológico , Estudos Retrospectivos , Hexafluoreto de Enxofre , Ativador de Plasminogênio Tecidual , Vitrectomia/efeitos adversos
19.
Quintessence Int ; 53(2): 144-154, 2022 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-34595909

RESUMO

OBJECTIVE: The primary objective of this meta-analysis (PROSPERO No: CRD42019124695) was to assess the association between psychologic stress, anxiety, and periodontitis. DATA SOURCES: The electronic search was conducted using PubMed, Embase, and Scopus, by three independent reviewers till December 2019. The search was limited to human studies published only in English language. The fixed-effect model and random-effects model were used to obtain the overall mean difference, odds ratio (OR), and its 95% CI for all studies. The heterogeneity was calculated by I2 statistics. The Newcastle--Ottawa scale was used to assess the risk of bias in the included studies. Out of 775 potentially relevant articles, 25 studies were selected for systematic review and only 14 studies could be used for meta-analysis in three subsets. The pooled OR for stress and periodontitis was 1.78, which was statistically highly significant (I2 = 98.6%, P = .00). Mean salivary cortisol levels as a measure of stress in patients with periodontitis was 4.81 nmol/L (I2 = 98.0%, P = .08). State-Trait Anxiety Inventory value was seen as -1.28 (I2 = 0.0%, P = .06) for state anxiety and -0.11 (I2 = 0.0%, P = .85) for trait anxiety in patients with periodontitis. CONCLUSION: The findings indicate a role of psychologic stress and anxiety in the progression of periodontitis.


Assuntos
Ansiedade , Periodontite , Objetivos , Humanos , Razão de Chances , Estresse Psicológico
20.
Retin Cases Brief Rep ; 16(3): 275-279, 2022 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-31977927

RESUMO

PURPOSE: To report two cases of widespread retinal pigment epithelial clumping, irregularity, and atrophy after uncomplicated 25-gauge pars plana vitrectomy with brilliant blue-green-assisted internal limiting membrane peeling. METHODS: Retrospective analysis of 2 eyes of 2 patients who underwent 25-gauge pars plana vitrectomy for macular diseases (macular hole with retinal detachment and vitreomacular traction) was performed. Surgical notes and video recordings were reviewed to determine the surgical procedures performed and the duration of the surgery. Multimodal imaging analysis, including fundus photography, fundus autofluorescence imaging, and optical coherence tomography were performed to determine the pathological changes in the postoperative period. RESULTS: The mean age of the patients (all females) was 78 years. In all the patients, brilliant blue-green-assisted internal limiting membrane peeling was performed without any intraoperative complications. Four weeks after an uncomplicated surgery, the patients complained of progressive central visual disturbance and metamorphopsia. Retinal imaging demonstrated retinal pigment epithelial clumps and irregularity, which appeared as hyperautofluorescent on fundus autofluorescence, and widespread retinal pigment epithelial atrophy (hypoautofluorescent on fundus autofluorescence) in the posterior pole and peripapillary region, along with retinal and choroidal thinning. CONCLUSION: In uncomplicated vitrectomy consisting of brilliant blue-green-assisted internal limiting membrane peeling, a remote risk of widespread retinal pigment epithelial damage exists even with the use of modern endoilluminators and relatively short surgical duration. Retinal phototoxicity seems to be the primary cause; however, dye-related cytotoxicity or a combination of both cannot be ruled out.


Assuntos
Membrana Epirretiniana , Perfurações Retinianas , Idoso , Atrofia/complicações , Membrana Basal/cirurgia , Membrana Epirretiniana/complicações , Membrana Epirretiniana/diagnóstico , Membrana Epirretiniana/cirurgia , Feminino , Humanos , Perfurações Retinianas/diagnóstico , Perfurações Retinianas/etiologia , Perfurações Retinianas/cirurgia , Pigmentos da Retina , Estudos Retrospectivos , Tomografia de Coerência Óptica , Acuidade Visual , Vitrectomia/efeitos adversos , Vitrectomia/métodos
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