Cyclic Load Impact Assessment of Long-Term Properties in Compression to Steel and Polyvinyl Alcohol Fibre-Reinforced Geopolymer Composites.

This study investigates the cyclic load application impact on fly-ash-based geopolymer composites that are reinforced with a low amount of fibre reinforcement. For reinforcement purposes, polyvinyl alcohol and steel fibres are used. For testing purposes, four geopolymer composite mixes were made, three of which had fibre reinforcement.

Different Fiber Reinforcement Effects on Fly Ash-Based Geopolymer Long-Term Deflection in Three-Point Bending and Microstructure.

This study investigated the effect of a low amount of polyvinyl alcohol (PVA) and steel fiber reinforcement on fly ash-based geopolymer composite long-term deflection and its microstructure. For testing purposes, specimens with different amounts and types of fiber reinforcement as well as plain (reference) were prepared. The long-term deflection test was performed by loading specimens with 40% of the ultimate flexural strength.

Creep and Shrinkage Behaviour of Disintegrated and Non-Disintegrated Cement Mortar.

One way to prevent cement from ending up in landfills after its shelf life is to regain its activity and reuse it as a binder. As has been discovered, milling by planetary ball mill is not effective. Grinding by collision is considered a more efficient way to refine brittle material and, in the case of cement, to regain its activity.

Foamed Geopolymer Composites with the Addition of Glass Wool Waste.

This study examines foamed geopolymer composites based on fly ash from the Skawina coal-fired power plant in Poland. The paper presents the effect of adding 3% and 5% by weight of glass wool waste on selected properties of foamed geopolymers. The scope of the tests carried out included density measurements, compressive and bending strength tests, measurements of the heat conduction coefficient, and the results of measurements of changes in thermal radiation in samples subjected to a temperature of 800 °C.

Comparison of LASIK outcomes with the Alcon LADARVision4000 and the VISX STAR S2 excimer lasers using optimized nomograms.

Purpose: To evaluate the difference in clinical outcomes between LASIK patients treated with the Alcon LADARVision4000 laser and the VISX STAR S2 laser using optimized nomograms.

Methods: Data from 572 LASIK surgeries of two groups that were sequentially performed by one surgeon were retrospectively reviewed. The first group of 286 eyes were the last cases performed with the VISX STAR S2 laser.

Factors that affect corneal flap thickness with the Hansatome microkeratome.

Purpose: To evaluate factors that influence corneal flap thickness with the Hansatome microkeratome.

Methods: One hundred thirty-two eyes of 70 patients underwent laser in situ keratomileusis (LASIK). Corneal flap thickness was measured by subtracting the intraoperative corneal bed pachymetry measurement from intraoperative total corneal pachymetry.

Comparison of laser phacovaporization using the Er-YAG and the Er-YSGG laser.

Objective: To study the interaction of the erbium (Er)-YAG (2.94 microns) and the Er-YSGG (2.79 microns) lasers with the human crystalline lens tissue.

A prototype erodible mask delivery system for the excimer laser.

Purpose: The authors developed an erodible mask delivery system for the argon-fluoride 193-nm excimer laser, which offers the possibility of correcting hyperopia and astigmatism as well as myopia.

Method: Masks were made of polymethylmethacrylate on a quartz window, with intended corrections for myopia and hyperopia of 2.5 and 5 diopters (D).

Current status of synthetic epikeratoplasty.

Many of the deficiencies with human tissue epikeratoplasty might be improved by the use of a suitable synthetic lenticule. Potential biomaterials for epikeratoplasty include collagen (types I, III, or IV), collagen-hydrogel copolymers, bioactive synthetics, and coated hydrogels. The biomaterial must be engineered to achieve strict specifications of optical clarity, support of epithelial migration and adhesion, permeability to solutes, and stability to corneal proteases.

Solid state ultraviolet laser (213 nm) ablation of the cornea and synthetic collagen lenticules.

We used a Q-switched Nd:YAG laser with non-linear optical crystals to produce the 5th (213 nm) and the 4th (266 nm) harmonic frequencies. Using these two wavelengths, we ablated fresh porcine corneas and type I collagen synthetic epikeratoplasty lenticules. For the 213-nm ablation, radiant exposure was 1.

Laser welding of synthetic epikeratoplasty lenticules to the cornea.

We used a milliwatt continuous wave CO2 laser mounted on an operating microscope to study the feasibility of welding synthetic collagen epikeratoplasty lenticules to the cornea. In vitro studies and experimentation in rabbits and monkeys showed no welding effects using direct laser radiation with powers ranging from 17 mW to 1 W. Only tissue shrinkage was observed.

Prostaglandin release following Nd:YAG iridotomy in rabbits.

In this study, iridotomies were performed in nine rabbit eyes using an Nd:YAG laser at 5.2 mJ, three pulses/burst, for one burst. Prostaglandin E2 (PGE2) in aqueous humor obtained at timed intervals after treatment was then measured using a sensitive and specific radioimmunoassay.

Effects of selected repeated intravitreal chemotherapeutic agents.

The toxic effects of repeated intravitreal injections of selected chemotherapeutic agents were studied in female albino rabbits. Three groups of eyes participated in each therapeutic regimen. Agents studied were doxorubicin (dox), 3 and 5 micrograms; 5-fluorouracil (5-FU), 0.