Laser-heating and Radiance Spectrometry for the Study of Nuclear Materials in Conditions Simulating a Nuclear Power Plant Accident.

Major and severe accidents have occurred three times in nuclear power plants (NPPs), at Three Mile Island (USA, 1979), Chernobyl (former USSR, 1986) and Fukushima (Japan, 2011). Research on the causes, dynamics, and consequences of these mishaps has been performed in a few laboratories worldwide in the last three decades. Common goals of such research activities are: the prevention of these kinds of accidents, both in existing and potential new nuclear power plants; the minimization of their eventual consequences; and ultimately, a full understanding of the real risks connected with NPPs. At the European Commission Joint Research Centre's Institute for Transuranium Elements, a laser-heating and fast radiance spectro-pyrometry facility is used for the laboratory simulation, on a small scale, of NPP core meltdown, the most common type of severe accident (SA) that can occur in a nuclear reactor as a consequence of a failure of the cooling system. This simulation tool permits fast and effective high-temperature measurements on real nuclear materials, such as plutonium and minor actinide-containing fission fuel samples. In this respect, and in its capability to produce large amount of data concerning materials under extreme conditions, the current experimental approach is certainly unique. For current and future concepts of NPP, example results are presented on the melting behavior of some different types of nuclear fuels: uranium-plutonium oxides, carbides, and nitrides. Results on the high-temperature interaction of oxide fuels with containment materials are also briefly shown.

24-hour efficacy of travoprost/timolol BAK-free versus latanoprost/timolol fixed combinations in patients insufficiently controlled with latanoprost.

INTRODUCTION: To compare the 24-h intraocular pressure (IOP) control and tolerability of travoprost/timolol benzalkonium chloride (BAK)-free (TTFC) vs. latanoprost/timolol fixed combination preserved with BAK (LTFC) in open-angle glaucoma patients insufficiently controlled with latanoprost 0.005% monotherapy given once in the evening. METHODS: The authors have conducted a prospective, observer-masked, active-controlled, cross-over, comparison study. Qualified open-angle glaucoma patients who demonstrated a latanoprost-treated morning IOP (10:00 ± 1 h) greater than 20 mmHg on two separate visits were randomized for 3 months to receive either TTFC or LTFC. Patients were then crossed over to the opposite treatment for another 3 months. At the end of the latanoprost run-in and after each 3-month therapy period patients underwent 24-h IOP monitoring in the habitual position using Goldmann applanation tonometry in the sitting position during the day (10:00, 14:00, 18:00 and 22:00) and Perkins tonometry in the supine position at night (02:00 and 06:00). Selected ocular surface parameters were evaluated after each therapy period. RESULTS: Forty-two open-angle glaucoma patients completed the study. The mean 24-h baseline IOP on latanoprost was 21.5 ± 1.6 mmHg. Both fixed combinations significantly reduced the IOP at each time point, for the mean, peak and fluctuation of 24-h IOP compared with latanoprost monotherapy (P < 0.01). When the two fixed combinations were compared directly, TTFC provided significantly lower mean 24-h IOP (18.9 ± 2.2 mmHg) vs. LTFC (19.3 ± 2.3 mmHg) (P = 0.004) and significantly lower IOP at 18:00 (18.6 ± 2.5 vs. 19.5 ± 2.7 mmHg for LTFC) (P < 0.001). Further, TTFC demonstrated significantly better tear film break-up time (5.15 vs. 4.65 s), corneal stain (1.5 vs. 1.8) and Schirmer I test (9.9 vs. 9.2 mm) compared with LTFC after 3 months of therapy (P < 0.01 for all comparisons). CONCLUSION: The mean 24-h IOP lowering of TTFC was statistically more significant compared to LTFC in patients insufficiently controlled with latanoprost monotherapy. Measurement of ocular surface health and tear film status favored the BAK-free TTFC compared to LTFC.

New perspectives on lamellar keratoplasty.

Lamellar (anterior and posterior) keratoplasty entails the surgical replacement of diseased-only corneal tissue, while healthy host corneal tissue is preserved. Selective keratoplasty offers several advantages in comparison to penetrating keratoplasty such as a lower rate of graft rejection, less endothelial cell loss, faster/superior visual rehabilitation and enhanced resistance to closed injury. The surgical approach of "partial corneal transplantation" may be divided into anterior and posterior: techniques including superficial and deep anterior lamellar keratoplasty (SALK and DALK, respectively) and endothelial keratoplasty as well as Descemet stripping automated endothelial keratoplasty (DSAEK) and Descemet membrane endothelial keratoplasty (DMEK). These novel surgical procedures are rapidly becoming the preferred therapy option for specific corneal dysfunctions involving the corneal stroma (SALK, DALK), or corneal endothelium (DSAEK, DMEK). During the past decade, the continuing advancement of surgical techniques and the development of innovative surgical instruments have significantly enhanced corneal transplantation. Lamellar keratoplasty techniques facilitate corneal surgery, provide patients with superior outcomes and can successfully restore vision in corneal-related blindness. Nevertheless, more long-term evidence is needed to better evaluate these promising new techniques.

Efficacy and safety of latanoprost versus travoprost in exfoliative glaucoma patients.

OBJECTIVE: To evaluate 24-hour intraocular pressure (IOP) efficacy of latanoprost versus travoprost, each given every evening, in exfoliative glaucoma patients. DESIGN: Prospective, observer-masked, crossover comparison. PARTICIPANTS: Forty patients with exfoliation glaucoma. METHODS: Patients with a pressure of >24 mmHg were randomized to latanoprost or travoprost for an 8-week treatment period after a 6-week medicine-free period. Patients were then switched to the opposite treatment for the second period. At untreated baseline and at the end of each treatment period the IOP was measured at 6 am, 10 am, 2 pm, 6 pm, 10 pm, and 2 am. MAIN OUTCOME MEASURE: Diurnal IOP. RESULTS: The mean 24-hour IOP was 25.1+/-2.5 mmHg at baseline, 17.8+/-2.1 mmHg on latanoprost, and 17.3+/-2.2 mmHg on travoprost (P = 0.001). Individual time points were similar between treatments, except at 6 pm when travoprost provided lower IOP (16.7+/-2.6 vs 17.9+/-2.5 mmHg, P<0.001). Adverse events showed more conjunctival hyperemia with travoprost (n = 15) than latanoprost (n = 6; P = 0.03). CONCLUSIONS: Latanoprost and travoprost both significantly reduce the 24-hour IOP from baseline in exfoliative glaucoma, but travoprost may demonstrate a greater hypotensive efficacy in the late afternoon.

Twenty-four-hour control with latanoprost-timolol-fixed combination therapy vs latanoprost therapy.

OBJECTIVE: To evaluate the 24-hour efficacy and safety of the latanoprost-timolol maleate-fixed combination vs latanoprost therapy in patients with primary open-angle glaucoma. METHODS: A prospective, observer-masked, crossover, active-controlled, randomized comparison in which after a 6-week medicine-free period, patients were randomized to either latanoprost-timolol-fixed combination therapy or latanoprost therapy, both dosed once each evening, alone for 8 weeks. Patients were then switched to the opposite treatment for 8 weeks. At the end of the washout and treatment periods, a 24-hour diurnal curve was performed. RESULTS: The baseline untreated mean +/- SD diurnal curve in 37 patients who completed the study was 24.2 +/- 2.0 mm Hg. The mean diurnal curve was 19.2 +/- 2.6 mm Hg for those who received latanoprost therapy alone and 16.7 +/- 2.1 mm Hg for those who received the fixed combination therapy (P<.001). The fixed combination therapy also provided a lower absolute intraocular pressure level (1.5-2.9 mm Hg, P<.001) and a greater intraocular pressure reduction from the untreated baseline (P<.001). Stinging was statistically lower with latanoprost therapy alone (P = .04), but itching was statistically increased compared with the fixed combination therapy (P = .04). CONCLUSION: The result of this study suggests that the latanoprost-timolol-fixed combination compared with latanoprost therapy alone provides improved intraocular pressure reduction over the 24-hour diurnal curve and for each individual time point in patients with primary open-angle glaucoma.