Safety-Aware Pursuit-Evasion Games in Unknown Environments Using Gaussian Processes and Finite-Time Convergent Reinforcement Learning.

This article develops a safe pursuit-evasion game for enabling finite-time capture, optimal performance as well as adaptation to an unknown cluttered environment. The pursuit-evasion game is formulated as a zero-sum differential game wherein the pursuer seeks to minimize its relative distance to the target while the evader attempts to maximize it. A critic-only reinforcement learning (RL)-based algorithm is then proposed for learning online and in finite time the pursuit-evasion policies and thus enabling finite-time capture of the evader. Safety is ensured by means of barrier functions associated with the obstacles, which are integrated into the running cost. Using Gaussian processes (GPs), a learning-based mechanism is devised for safely learning the unknown environment. Simulation results illustrate the efficacy of the proposed approach.

Prospective study comparing Xalatan® eye drops and two similar generics as to the efficacy and safety profile.

PURPOSE: To evaluate the efficacy and safety between two generic prostaglandins Lataz-Xalaprost (Greece) and the corresponding original drops (Xalatan®). MATERIAL AND METHODS: In this prospective randomized study, 60 patients diagnosed with open-angle glaucoma or ocular hypertension were enrolled, who had never received antiglaucoma treatment. Subjects were divided randomly into three groups (Xalatan, Lataz, and Xalaprost groups) and they were studied over 16 weeks. At each visit, the mean applanation tonometry values and tear break-up time were measured. The Ocular Surface Disease Index questionnaire was used to evaluate patient's symptoms. RESULTS: There was a statistically significant difference (p < 0.001) in the mean values of the intraocular pressure between the baseline and the last visit (Xalatan group: from 23.11 ± 1.61 mmHg to 15.81 ± 1.22 mmHg, Lataz group: from 23.26 ± 1.33 mmHg to 15.80 ± 1.47 mmHg, and Xalaprost group: from 23.08 ± 1.45 mmHg to 16.08 ± 1.38 mmHg). Both generic eye drops showed mean percentage intraocular pressure reduction comparable to the standards of prostaglandin analogues (Xalatan: 31.57%, Lataz: 32.06%, and Xalaprost: 30.34%). Xalatan reduced the tear break-up time less, followed by Lataz and then by Xalaprost (Xalatan: from 8.5 to 8 s, Lataz: from 8.2 to 7.4 s, and Xalaprost: from 8.7 to 7.7 s). Xalatan presented the best safety profile, followed by Lataz and least was Xalaprost, according to Ocular Surface Disease Index questionnaire's results. CONCLUSION: No significant difference was recorded in the effectiveness of each generic prostaglandin compared to the original. Furthermore, no patient had to change medication. The differences that arose in the safety profile of the three eye drops suggest a prompt closer initial monitoring of patients who are administered generic eye drops.

Polymorphism Analysis of VSX1 and SOD1 Genes in Greek Patients with Keratoconus.

BACKGROUND: A number of mutations in the VSX1 and SOD1 genes have been reported to be associated with keratoconus (KC), however the results from different studies are controversial. In this study, we conducted the genotyping of common polymorphisms [VSX1: D144E, H244R, R166W, G160D; SOD1: intronic 7-base deletion (c.169 + 50 delTAAACAG)], in a case-control sample panel of the Greek population. MATERIALS AND METHODS: A case-control panel, with 33 KC patients and 78 healthy controls, were surveyed. DNA from each individual was tested for the VSX1: D144E, H244R, R166W, G160D and SOD1: intronic 7-base deletion (c.169 + 50 delTAAACAG) polymorphisms by direct sequencing. RESULTS: We observed no polymorphisms of the VSX1 gene in the case-control panel. Concerning the SOD1 intronic 7-base deletion (c.169 + 50 delTAAACAG), our findings suggest that heterozygous carriers are over-represented among KC cases compared to healthy controls (p = 0.002). CONCLUSIONS: We cannot confirm the previously reported association of the polymorphism in the VSX1 gene with KC. Our results suggest a possible causative role of SOD1 in the pathogenesis of KC. Further studies are required to identify other important genetic factors involved in the pathogenesis and progression of KC.

Polymorphism analysis of COL4A3 and COL4A4 genes in Greek patients with keratoconus.

BACKGROUND: In this study, we conducted the genotyping of D326Y in COL4A3 and M1327V, as well as F1644F in COL4A4 polymorphisms, in a case-control sample panel of Greek origin population. MATERIALS AND METHODS: A case-control panel, with 45 keratoconus (KC) patients and 78 healthy controls, were surveyed. DNA from each individual was tested for the D326Y in COL4A3 and M1327V, as well as F1644F in COL4A4 polymorphisms by direct sequencing. RESULTS: When analyzing the Hardy-Weinberg equilibrium, we observed no significant deviation from expected numbers in both KC patients and controls. The genotype frequencies in the polymorphisms tested were not found to be significantly associated with KC development risk. The M1327V AA and F1644F TT genotypes were significantly over-represented in healthy individuals. CONCLUSIONS: We could hypothesize that mutations in COL4A3 and COL4A4 genes are not involved in KC risk in Greek population. Nevertheless, the M1327V AA and F1644F TT genotypes were significantly over-represented in healthy individuals, suggesting a protective role of these genotypes in KC development risk in our population.