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Objective: To analyze the epidemiology of pterygium in a hospital-based population in Al-Khobar, which is located in the eastern province of Saudi Arabia. Materials and Methods: This was a retrospective, non-randomized, and consecutive case study. Out of 88,666 patients who were seen in the ophthalmology clinic between January 1995 through the end of December 2010, 116 patients were diagnosed with advanced pterygium. The medical records of these patients were evaluated. Results: The overall prevalence of pterygium was found to be 0.074%. There was no significant difference by either gender, side, or by laterality (P > 0.05). A significant increase was noticed in the prevalence of pterygium with increasing age and nasal location (P < 0.05). Conclusion: The overall prevalence rate of pterygium in Al-Khobar is low when compared with results reported from other areas of the world.

Time-resolved diffuse X-ray scattering with 50 fs, 9.5 keV X-ray pulses from the Linear Coherent Light Source was used to study the structural dynamics in materials undergoing rapid melting and ablation after fs laser excitation.

The paper examines the discretionary nature of (non)capitalizing development expenditures in financial statements. A review of the literature shows that companies may have different motives and factors for (non)capitalizing development expenditures. This study analyzes a sample of 547 companies from the information and communications technology (ICT) sector listed on the Frankfurt Stock Exchange in the period 2009-2018. The ICT sector was selected because it represents an industry with high R&D (research and development) expenditures. The results of the probit regression analysis made on 3,718 observations show that the capitalization of development expenditures is significantly positively related to the size and return on assets of the firm and negatively related to the age of the firm. Larger and more profitable firms are more likely to capitalize development expenditures, while older firms are less likely to capitalize development expenditures. Our results contribute to the literature in the field of positive accounting theory providing additional insights into factors associated with decisions to (non)capitalize development expenditures.

Studies show an increasing importance of intangible assets (hereinafter IA) and a positive relationship between IA and company performance. The purpose of this paper is to analyse the importance of IA for Croatian and Slovene hotel companies and to find out whether companies with a higher share of intangibles are also more profitable. The analysis is based on publicly available financial statements for the five-year period, from 2011 to 2015. The results show that the average share of IA presented in the balance sheets of the analysed hotel companies is low in both countries. Moreover, we could not find a statistically significant relationship between the share of IA and the selected financial performance indicators. The results of our study show that despite the emphasised importance of IA in literature, the publicly available financial data of the selected hotel companies provides very limited information on IA for external stakeholders.

Objective: To analyze the epidemiology of pterygium in a hospital-based population in Alkhobar, which is located in the eastern province of Saudi Arabia. Materials and Methods: This was a retrospective, non-randomized, and consecutive case study. Out of 88,666 patients who were seen in the ophthalmology clinic between January 1995 through the end of December 2010, 116 patients were diagnosed with advanced pterygium. The medical records of these patients were evaluated. Results: The overall prevalence of pterygium was found to be 0.074%. There was no significant difference by either gender, side, or by laterality (P > 0.05). A significant increase was noticed in the prevalence of pterygium with increasing age and nasal location (P < 0.05). Conclusion: The overall prevalence rate of pterygium in Alkhobar is low when compared with results reported from other areas of the world. [ABSTRACT FROM AUTHOR]

In this paper the reaction heat development of alkali activated aluminosilicates is studied by an isothermal heat flow calorimeter. The highest reaction activity is observed during two hours after mixing. The hydration heat power at early time is influenced mainly by the composition of tested mixtures involving ceramic dust as precursor and different amounts of sodium hydroxide and water glass as activators and by temperature.

Let A be an invertible 3 × 3 complex matrix. It is shown that there is a 3 × 3 permutation matrix P such that the product PA has at least two distinct eigenvalues.

Plasma electrolytic polishing (PeP) is mainly used to improve the surface quality and thus the performance of electrically conductive parts. It is usually used as an anodic process, i.e., the workpiece is positively charged. However, the process is susceptible to high current peaks during the formation of the vapour-gaseous envelope, especially when polishing workpieces with a large surface area. In this study, the influence of the anode immersion speed on the current peaks and the average power during the initialisation of the PeP process is investigated for an anode the size of a microreactor mould insert. Through systematic experimentation and analysis, this work provides insights into the control of the initialisation process by modulating the anode immersion speed. The results clarify the relationship between immersion speed, peak current, and average power and provide a novel approach to improve process efficiency in PeP. The highest peak current and average power occur when the electrolyte splashes over the top of the anode and not, as expected, when the anode touches the electrolyte. By immersion of the anode while the voltage is applied to the anode and counterelectrode, the reduction of both parameters is over 80%.

Caffeine is a verified bio-protective substance in the fight against the biodegradation of cellulose materials, but its ecotoxicity in this context has not yet been studied. For this reason, the ecotoxicity of flax-fiber-reinforced epoxy composite with or without caffeine was tested in the present study. Prepared samples of the composite material were tested on freshwater green algal species ( Hematococcus pluvialis ), yeasts ( Saccharomyces cerevisae ), and crustacean species ( Daphnia magna ). Aqueous eluates were prepared from the studied material (with caffeine addition (12%) and without caffeine and pure flax fibers), which were subjected to chemical analysis for the residues of caffeine or metals. The results indicate the presence of caffeine up to 0.001 mg/L. The eluate of the studied material was fully toxic for daphnids and partially for algae and yeasts, but the presence of caffeine did not increase its toxicity statistically significantly, in all cases. The final negative biological effects were probably caused by the mix of heavy metal residues and organic substances based on epoxy resins released directly from the tested composite material.

The petroleum industry is often faced with accidental spills and discharges that pollute valuable natural resources such as soil. The purpose of this study was to assess bioremediation potential of an on-site landfarming unit (LU), a highly economical solution that complies with the zero-waste policy, for bioremediation of the contaminated soil after an actual diesel fuel leakage in a fuel depot. The first aim was to evaluate the effects of different climates on hydrocarbon bioremediation. For this reason, a part of the contaminated soil was moved from the initial location with a sub-Mediterranean climate to an LU at another location with a temperate continental climate. Our results demonstrated that remediation in sub-Mediterranean climate is less effective than the remediation in a temperate continental climate. The second aim of this study was to evaluate the effect of different plant species on the microbial population during bioremediation. For that purpose, 365-day monitoring of phospholipid fatty acids (PLFA) was performed. Our results support the hypothesis that plant-assisted bioremediation can diminish toxic effects of diesel-polluted soil and that the changes in plant species during bioremediation cause changes in the microbial population.

Bone glue with sodium lignosulfonate is a protein-based adhesive. Their combination leads to strong binding necessary for the achievement of adhesive properties. However, biodegradation and ecotoxicity of materials composed of bone glue and sodium lignosulfonate has never been studied before. In this paper, the biodegradation potential of the mixture of bone glue, lignosulfonate and rape straw modified by water or NaOH on an agar test with aerial molds and in acute aquatic tests with mustard, yeasts, algae and crustaceans was analyzed. Epoxy resin as an ecologically unfriendly binder was used as a negative control and pure rape straw as a background. The results indicated that all samples were covered by molds, but the samples containing straw treated by NaOH showed lower biodegradability. The ecotoxicological effects varied among the applied model organisms. Artemia salina was not able to survive and S. alba could not prolong roots in the eluates of all samples (100% inhibition). Freshwater algae ( D. subspicatus ) were not significantly affected by the samples (max. 12% inhibition, max. 16% stimulation). The biomass of yeasts ( S. cerevisae ) was strongly stimulated in the presence of eluates in a comparison to control (max. 38% stimulation).

3D-printing technology is opening up new possibilities for the co-printing of sensory elements. While quasi-static research has shown promise, the dynamic performance has yet to be researched. This study researched smart 3D structures with embedded and printed sensory elements. The embedded strain sensor was based on the conductive PLA (Polylactic Acid) material. The research was focused on dynamic measurements of the strain and considered the theoretical background of the piezoresistivity of conductive PLA materials, the temperature effects, the nonlinearities, the dynamic range, the electromagnetic sensitivity and the frequency range. A quasi-static calibration used in the dynamic measurements was proposed. It was shown that the temperature effects were negligible, the sensory element was linear as long as the structure had a linear response, the dynamic range started at ∼ 30 μ ϵ and broadband performance was in the range of few kHz (depending on the size of the printed sensor). The promising results support future applications of smart 3D-printed systems with embedded sensory elements being used for dynamic measurements in areas where currently piezo-crystal-based sensors are used.

Lead, a highly toxic element, is frequently present in various solid wastes as well as in industrial effluents. Sorption with a low cost sorbent is a simple way of Pb removal from liquid streams, but stabilization of spent sorbent has to be ensured in order to prevent Pb leaching out and possible environmental contamination. In previous research, ceramic sorbent, generated as waste product in brick industry, was tested as sorbent and proved high sorption capacity for lead. Lead was sorbed partially as hydrocerussite and partially as adsorbed surface layer. The Pb leaching from sorbent was very high and thus further immobilization of sorbent was necessary. Lead, as well as other heavy metals, is known as retarder of the hydration process of Ordinary Portland Cement (OPC), used for the immobilization. In this paper, influence of sorbed Pb and PbO, as reference compound, on cement hydration was studied by calorimetry, thermogravimetry and Magic Angle Spinning Nuclear Magnetic Resonance Spectroscopy (MAS NMR). The sorbed lead was found to be less detrimental to hydration retardation due to the lower solubility of precipitated hydrocerussite in basic environment compared to PbO, which forms plumbate anion.

Series of amorphous SiO2, ZrO2 and HfO2 films were prepared by electron-beam evaporation at various oxygen pressures such that the packing density varied from 0.6 to 0.82. Transmittance spectra were evaluated with respect to thickness and refractive index by application of analytical formulas to the interference extrema and by dielectric modeling. The thickness of the films ranged from 150 to 1500 nm. The coefficients of Cauchy and Sellmeier dispersion curves were determined as a function of the packing density. The mass density of the compact amorphous grains was estimated by an effective-medium theory and a general refractivity formula. It is similar to those of the crystalline materials. We used the optical data to design multilayer coatings for laser applications in a broad spectral range, including the UV.