Evaluation of the retina, choroid and optic disc vascular structures in individuals with a history of COVID-19.

INTRODUCTION: In this study, we aimed to detect changes in posterior segment structures and vascular density caused by COVID-19 using an optical coherence tomography angiography (OCTA) device. MATERIALS AND METHODS: The study included 20 eyes of 20 patients no systemic or ocular disease who were followed at the Ophthalmology Clinic of Health Sciences University Antalya Training and Research Hospital. The OCTA images of these individuals taken prior to contracting COVID-19 and six months after recovery were examined. RESULTS: The mean choriocapillaris blood flow was 2.00±0.13mm2 before COVID-19 and 2.08±0.23mm2 after the disease, and the mean subfoveal choroidal thickness was 247.33±7.65µm before the disease and 273.08±4.92µm after the disease, indicating a statistically significant difference (P=0.003, P=0.001, respectively). The mean retinal nerve fiber layer thickness before and after COVID-19 were 119.33±3.88 and 117.50±3.92µm, respectively, representing a statistically significant decrease (P<0.001). CONCLUSION: This is the first study in the literature to evaluate the post-COVID-19 changes in the vascular structures of the eye compared to the pre-disease values. In this study, we found statistically significant changes in choriocapillaris blood flow, subfoveal chroidal thickness and retinal nerve fiber layer thickness after COVID-19 infection. Further research with a greater sample size is needed to explore the effect of COVID-19 on these parameters.

Anaerobic co-digestion of oil-extracted spent coffee grounds with various wastes: Experimental and kinetic modeling studies.

The effect of oil extraction from spent coffee grounds as a pre-treatment strategy prior to anaerobic digestion besides assessing the feasibility of defatted spent coffee grounds co-digestion with spent tea waste, glycerin, and macroalgae were examined. Mesophilic BMP tests were performed using defatted spent coffee grounds alongside four co-substrates in the ratio of 25, 50, and 75%, respectively. The highest methane yield was obtained with the mono-digestion of defatted spent coffee grounds with 336 ± 7 mL CH4/g VS and the yield increased with the increase in the mass ratio of defatted spent coffee grounds during co-digestion. Moreover, defatted spent coffee grounds showed the highest VS and TS removal at 35.5% and 32.1%, respectively and decreased thereafter. Finally, a linear regression model for the interaction effects between substrates was demonstrated and showed that distinctly mixing defatted spent coffee grounds, spent coffee grounds, and spent tea waste outperforms other triple mixed substrates.

Investigation of the factors affecting the photothermal therapy potential of small iron oxide nanoparticles over the 730-840 nm spectral region.

The use of superparamagnetic iron oxide nanoparticles (SPIONs) as a sensitizer in photothermal therapy (PTT) is relatively new and the origin of such a phenomenon is not known. Usually, large crystals and aggregated particles are preferred in the literature, suggesting that these increase the absorbance of particles at the irradiation wavelength, and hence, provide a larger temperature increase. This study has two major goals: identification of the key factors that affect the photo-induced temperature increase in well-controlled experiments and the influence of laser irradiation on nanoparticle properties. Small, biocompatible poly(acrylic acid) coated SPIONs (PAA/SPIONs) were used since they are more practical for future medical use than large aggregates. We studied the impact of three major laser-dependent variables, namely the wavelength (between 728 and 838 nm), intensity (1.85-9.76 W cm-2) and power (105-800 mW) as well as attenuation at the irradiation wavelength, on photothermal heating achieved with PAA/SPIONs. Within the studied range of these variables, only the laser power plays a critical role on the magnitude of photothermal heating in solutions. There is no strong correlation between the attenuation at the excitation wavelength and the temperature increase. In addition, extensive characterization of SPIONs before and after irradiation revealed no significant difference, which supports the re-usability of SPIONs. Lastly, the PTT potential of these small PAA/SPIONs was demonstrated in vitro on HeLa cells. At these low laser powers no temperature increase in SPION-free water or cell death in SPION-free cells was detected. Hence, this study provides a new insight into the photothermal effect of SPIONs, provides a clear and repeatable experimental procedure and demonstrates great potential for small SPIONs to be exploited in PTT.

One step emission tunable synthesis of PEG coated Ag2S NIR quantum dots and the development of receptor targeted drug delivery vehicles thereof.

PEGylation of quantum dots (QDs) to decrease their toxicity, increase blood circulation time, reduce non-specific uptake and also to solubilize and stabilize hydrophobic QDs in aqueous medium is a widely used approach and many different methods were developed to achieve this. QDs that are luminescent in the near-infrared region (NIR) have recently emerged as the more appropriate materials for bio-imaging studies. In this work, we describe a single step emission tunable aqueous synthesis of PEGylated Ag2S NIRQDs. They are highly cytocompatible, not only due to the PEG coating but also due to the intrinsic biocompatibility of Ag2S, and prepared in a single step aqueous method using thiolated PEGs as the only coating material. Tuning the emission wavelength within the medical window (775-930 nm) with a quantum yield between 2 and 65% is achieved by changing the reaction variables such as PEG molecular weight, pH and precursor ratios. Ag2S-PEG NIRQDs prepared from 5 kDa MPEG-SH at acidic pH provided a dramatic enhancement in the luminescence intensity. These NIRQDs were also designed with surface functional groups to attach folic acid and loaded with doxorubicin (DOX) which dramatically enhanced the uptake and efficacy of DOX (50% cell death with 15 nM DOX) in FA-receptor overexpressed cancer cell lines (HeLa). They also showed a strong cytoplasmic NIR signal in the in vitro studies, demonstrating great theranostic potential.

Screening for the fragile X syndrome among mentally retarded males by hair root analysis.

A noninvasive antibody test was used to identify male fragile X patients in special education schools, on the basis of the lack of FMRP in hair roots. We studied 300 males with mental retardation of unknown cause attending special schools. Patients were divided into two groups, based on the scores according to a fragile X check list (Group 1 /= 10 points). Group 2 consists of 51 males and only 5 males in this group showed no FMRP expression in hair roots within the abnormal range (91%). Fragile X diagnosis in these cases was confirmed by DNA analysis. None of the males scoring more than 10 on the check list was diagnosed positive for the fragile X syndrome using DNA analysis. With our antibody test on hair roots we did not detect a fragile X patient in Group 1. The FMRP antibody test on hair roots is suitable in a screening program for the fragile X syndrome among mentally retarded males attending special education schools.

Epidemiological evaluation of the protection conferred by the Nivgrip vaccine against influenza caused by the A(H3N2) virus.

The protection conferred by the inactivated influenza vaccine Nivgrip against influenza caused by the A(H3N2) virus was demonstrated in three school communities of a large urban centre during the epidemic outbreaks occurring in the winter season of 1983. The specific protection was reflected by the lower morbidity by influenza-like respiratory infections and by the absence or scarcity of postinfluenza complications in vaccinees.