ABSTRACT
Nanocomposites comprising nitrogen-doped TiO2 and reduced graphene oxide (N/TiO2/rGO), with different rGO loading qualities, were prepared by a cost-effective microwave-assisted synthesis method. The synthesized materials were broadly characterized by Raman spectroscopy, X-ray diffraction (XRD), infrared spectroscopy (FTIR), photoelectron spectroscopy (XPS), diffuse reflectance spectroscopy (DRS), electron microscopy (SEM-EDS), and nitrogen adsorption/desorption isotherms. Anatase was the only crystalline phase observed for all synthesized materials. The rGO loading did not affect the morphological properties, but it positively influenced the photocatalytic activity of the nanocomposite materials, especially at low rGO loading. Photocatalysts were evaluated via the degradation of specific organic micropollutant (OMP) pharmaceuticals: ciprofloxacin (CIP), diclofenac (DCF), and salicylic acid (SA), under different radiation sources: ultraviolet A (UVA), solar light simulator (SLS), blue visible light (BVL) and cold visible light (CVL). CIP and SA were removed effectively via the synergy of adsorption and photocatalysis, while DCF degradation was achieved solely by photocatalysis. After implementing scavenger agents, photocatalytic degradation processes mainly depended on the specific pollutant type, while irradiation sources barely defined the photocatalytic mechanism. On the other hand, changes in irradiation intensity significantly influenced the photolysis process, while photocatalysis was slightly affected, indicating that irradiation spectra are more relevant than intensity.
ABSTRACT
Nitrogen-doped TiO2 (N/TiO2) photocatalyst nanoparticles were derived by the environmentally friendly and cost-effective microwave-assisted synthesis method. The samples were prepared at different reaction parameters (temperature and time) and precursor ratio (amount of nitrogen source; urea). The obtained materials were characterized by X-ray diffraction (XRD), photoelectron spectroscopy (XPS), Raman spectroscopy (RS), infrared spectroscopy (FTIR), diffuse reflectance spectroscopy (DRS), electron microscopy (SEM-EDS), and nitrogen adsorption/desorption isotherms. Two cycles of optimizations were conducted to determine the best reaction temperature and time, as well as N content. The phase composition for all N/TiO2 nanomaterials was identified as photoactive anatase. The reaction temperature was found to be the most relevant parameter for the course of the structural evolution of the samples. The nitrogen content was the least relevant for the development of the particle morphology, but it was important for photocatalytic performance. The photocatalytic activity of N/TiO2 nanoparticle aqueous suspensions was evaluated by the degradation of antibiotic ciprofloxacin (CIP) under different irradiation spectra: ultraviolet A light (UVA), simulated solar light, and visible light. As expected, all prepared samples demonstrated efficient CIP degradation. For all irradiation sources, increasing synthesis temperature and increasing nitrogen content further improved the degradation efficiencies.
ABSTRACT
The case of a 36 year-old male with neuroretinitis caused by Bartonella henselae is reported, whose periodic follow-up was done through optical coherence tomography (OCT). The onset of this disease was characterized by unilateral low visual acuity (VA), painless, of sudden onset, in the right eye (RE), associated to l febrile symptom. The funduscopic examination showed edema in the posterior pole which extended from the optical disc to the macular region in the RE. The OCT confirmed macular and optical disc thickening, as well as the presence of subretinal macular fluid. Systemic studies were normal except for a blood count due to the presence of leukocytosis and positive for Bartonella henselae. The follow up with CT Scan helped to evaluate the decrease in macular edema, with the subsequent improvement of visual acuity and absence of related complications. This report describes the utility of the follow up with OCT in a patient with neuroretinitis caused by Bartonella henselae.
Subject(s)
Cat-Scratch Disease/diagnosis , Retinitis/diagnosis , Retinitis/microbiology , Tomography, Optical Coherence , Adult , Follow-Up Studies , Humans , MaleABSTRACT
Se reporta el caso de un varón de 36 años con neurorretinitis por Bartonella henselae, cuyo seguimiento periódico fue realizado con tomografía de coherencia óptica (TCO). El inicio de la enfermedad se caracterizó por disminución de agudeza visual (AV) unilateral, indolora, de inicio brusco en ojo derecho (OD), asociado a cuadro febril. El examen fundoscópico mostró edema en polo posterior, extendiéndose desde el disco óptico hasta la región macular en OD. La TCO confirmó el engrosamiento macular y del disco óptico así como la presencia de fluido macular subretinal. Los estudios sistémicos fueron normales con excepción del hemograma por presencia de leucocitosis y serología positiva a Bartonella henselae. El seguimiento tomográfico permitió valorar la disminución del edema macular, con la correspondiente mejora de la agudeza visual y ausencia de complicaciones asociadas. Este reporte describe la utilidad del seguimiento con TCO en un paciente con neurorretinitis por Bartonella henselae.
The case of a 36 year-old male with neuroretinitis caused by Bartonella henselae is reported, whose periodic follow-up was done through optical coherence tomography (OCT). The onset of this disease was characterized by unilateral low visual acuity (VA), painless, of sudden onset, in the right eye (RE), associated to l febrile symptom. The funduscopic examination showed edema in the posterior pole which extended from the optical disc to the macular region in the RE. The OCT confirmed macular and optical disc thickening, as well as the presence of subretinal macular fluid. Systemic studies were normal except for a blood count due to the presence of leukocytosis and positive for Bartonella henselae. The follow up with CT Scan helped to evaluate the decrease in macular edema, with the subsequent improvement of visual acuity and absence of related complications. This report describes the utility of the follow up with OCT in a patient with neuroretinitis caused by Bartonella henselae.
Subject(s)
Adult , Humans , Male , Cat-Scratch Disease/diagnosis , Retinitis/diagnosis , Retinitis/microbiology , Tomography, Optical Coherence , Follow-Up StudiesABSTRACT
PURPOSE: To compare astigmatism correction using shorter arc length 90°/120° asymmetric Intacs severe keratoconus (SK) versus 150° single-segment Intacs SK in cases of asymmetric keratoconus. METHODS: Retrospective prospective study in patients of asymmetric keratoconus with more than 2 diopters (D) of refractive astigmatism. Group 1 included 16 eyes of 16 patients who underwent 150° single-segment Intacs SK implantation, and group 2 included 16 eyes of 12 patients who underwent asymmetric shorter arc length 90°/120° Intacs SK implantation. Patients younger than 35 years were cross-linked. Parameters studied included preoperative and postoperative (1 and 9 months) uncorrected distance visual acuity (UDVA), best corrected distance visual acuity (CDVA), manifest refraction, and corneal topography. RESULTS: Both groups demonstrated significant improvement in UDVA, CDVA, spherical equivalent (SE), and manifest cylinder after the surgery. Comparison of change (post-pre) in UDVA, CDVA, and SE at the 1- and 9-month postoperative visits demonstrated significant improvement without statistically significant difference between the 2 groups. However, change in manifest cylinder at 1 month was statistically significantly higher in group 2 (4.65 ± 2.21 D) versus group 1 (2.29 ± 1.57 D) (P = 0.001). At the 9-month visit, change in manifest cylinder continued to be higher at 3.43 ± 1.79 D in group 2 versus 2.58 ± 1.29 D in group 1; however, this difference was not statistically significant (P = 0.17). CONCLUSIONS: Implantation of asymmetric shorter arc length 90°/120° Intacs SK segments achieved 33% higher correction of astigmatism compared with 150° single-segment Intacs SK implantation. Improvement in UDVA, CDVA, and SE was comparable.
