ABSTRACT
A two-phase system for biogas production from cheese whey wastewater (CWW) was designed, set up and operated at laboratory and full scale for a whole cheese production season (8-9 months). The high efficiency and stability of the laboratory-scale system was demonstrated under various organic loading rates (OLRs) reaching 13 g chemical oxygen demand (COD) L(-1)d(-1) and producing up to 9 L L(-1)d(-1) of biogas (approximately 55% in methane). The COD removal was above 95% and the pH was maintained above 6.3 without any chemical addition. The full-scale system was operated at lower OLRs than its normal capacity, following the good response and high stability in disturbances of the laboratory-scale unit.
Subject(s)
Biofuels , Bioreactors , Wastewater , Anaerobiosis , Cheese , Food Industry , Industrial WasteABSTRACT
This paper presents a novel algorithm for training radial basis function (RBF) networks, in order to produce models with increased accuracy and parsimony. The proposed methodology is based on a nonsymmetric variant of the fuzzy means (FM) algorithm, which has the ability to determine the number and locations of the hidden-node RBF centers, whereas the synaptic weights are calculated using linear regression. Taking advantage of the short computational times required by the FM algorithm, we wrap a particle swarm optimization (PSO) based engine around it, designed to optimize the fuzzy partition. The result is an integrated framework for fully determining all the parameters of an RBF network. The proposed approach is evaluated through its application on 12 real-world and synthetic benchmark datasets and is also compared with other neural network training techniques. The results show that the RBF network models produced by the PSO-based nonsymmetric FM algorithm outperform the models produced by the other techniques, exhibiting higher prediction accuracies in shorter computational times, accompanied by simpler network structures.
ABSTRACT
BACKGROUND: In the literature there have often been reports about deposits (hydroxyapatite) in hydrophilic or hydrophobic intraocular lenses (IOLs). We report, for the first time, about deposits on a silicone IOL of the second generation. MATERIALS AND METHODS: A silicone IOL (Allergan, type SI-40) which was extracted due to gradual visual loss, has been examined. RESULTS: The examination with the scanning electron microscope (SEM) showed crystalline precipitations in the anterior surface of the IOL while the X-ray analysis showed the existence of calcium and carbon, whereas no phosphorus was found. CONCLUSIONS: It could be hypothesised that metabolic disorders in aqueous humor (i. e., in patients with diabetes mellitus), the quality of the production of the lens, and not the IOL material, are the main cause for deposits in the IOL surface.
Subject(s)
Equipment Failure Analysis , Lenses, Intraocular , Silicones , Aged , Calcium/analysis , Carbon/analysis , Crystallization , Device Removal , Diabetes Complications , Durapatite/analysis , Electron Probe Microanalysis , Humans , Hydrogel, Polyethylene Glycol Dimethacrylate , Male , Microscopy, Electron , Phosphorus/analysis , Postoperative Complications/etiology , Postoperative Complications/surgery , Prosthesis Design , Risk FactorsABSTRACT
In the last five years, 25 cases of retinal detachment (RD) after intraocular lens implantation were treated in the University Eye Clinic of Thessaloniki. The incidence of RD was lower with posterior chamber intraocular lens (PC-IOL, 0.46%) implantation than in the cases with anterior chamber IOL (AC-IOL, 2.6%) implantation. The successful reattachment rate was higher with PC-IOL (100%) than in cases with AC-IOL where the low success (87%) rate was caused by proliferative vitreoretinopathy. Therefore, the eyes with AC-IOL required reoperation more frequently, and the ultimate failure rate (despite multiple operations) was higher in the AC-IOL group. Conventional surgical techniques were used in the first procedure. In the reoperated cases, the most advanced techniques were used, such as vitrectomy combined with gas or silicone oil injection.
Subject(s)
Lenses, Intraocular/adverse effects , Retinal Detachment/surgery , Cataract Extraction , Humans , Incidence , Lenses, Intraocular/classification , Prognosis , Reoperation , Retinal Detachment/etiology , Visual Acuity , Visual FieldsABSTRACT
A case is described in which the patient had been struck by lightning, with involvement of one eye and the visual pathways. Ophthalmological examination revealed a posterior capsule cataract in the right eye and peripheral constriction of the visual field of the left eye, although central vision in the left eye was not affected. The peak latency of the pattern reversal-evoked potentials in the left eye was longer and their amplitude lower. The skin ERG was normal. The CT scan revealed a thickening of the left optic nerve. The importance of electrophysiological and CT scan examination in the diagnosis and etiology of abnormalities caused in the eye by lightning is emphasized.
Subject(s)
Electric Injuries/diagnosis , Electroretinography , Lightning , Optic Nerve Injuries , Tomography, X-Ray Computed , Adult , Cataract/diagnosis , Evoked Potentials, Visual , Female , Humans , Male , Optic Nerve/pathology , Reaction Time , Visual Acuity , Visual FieldsABSTRACT
Ultrasonography, and especially the combined use of A- and B-scan echography, is one of the most important methods of clinical investigation in ophthalmology, It was employed on 1000 patients with opaque media. In 158 cases the examination confirmed the diagnosis of pathologic changes, while in the rest the echograms were normal. The most frequent finding was retinal detachment. Echography is also the most important examination for selection and preoperative examination of candidates for vitrectomy.
Subject(s)
Eye Diseases/diagnosis , Ultrasonography , Humans , Retinal Detachment/diagnosisABSTRACT
Band keratopathy may be treated either surgically or by using chelating agents. If central corneal scars are present corneal grafting is indicated while in their absence dissolving therapy is preferable. Eight successful corneal grafts and three cases treated medically are reported. Details of treatment with sodium EDTA are described.
Subject(s)
Calcinosis/therapy , Corneal Opacity/therapy , Adult , Aged , Corneal Transplantation , Edetic Acid/therapeutic use , Female , Humans , Transplantation, HomologousABSTRACT
Paraffin-embedded sections of eyes enucleated because of hydrophthalmos (23 cases) or retinoblastoma (59 cases) were examined for vascular changes within the proximal optic nerve. Globes of adults, enucleated because of secondary glaucoma (146 cases), were studied for comparison as well as 19 myopic and 11 microphthalmic eyes enucleated for other reasons, and 19 autopsy eyes of newborns. Microscopic examination revealed an accumulation of dilated thin-walled blood vessels within the septae of the proximal optic nerve of 6 eyes with hydrophthalmos and 11 eyes with retinoblastoma; sometimes the vascular changes appeared somewhat similar to an angioma racemosum. A common finding in all 17 cases was an elevation of the intraocular pressure. There were only 2 cases among the eyes studied for comparison showing dilatations of the optic nerve capillaries: 1 was in a stillborn baby with general hyperemia, and the other was a case of secondary glaucoma in an adult. 9 similar cases have hitherto been published describing vascular dilatations in the optic nerve of children suffering either from glaucoma or retinoblastoma; none of the authors had related these changes to an increased intraocular pressure. It seems likely that hemodynamic changes play an important role in the pathogenesis of these vascular reactions in the proximal optic nerve of infants with flaucoma. A lower arterial blood pressure in infants as well as anatomical and morphological features may be further factors of significance.