Reduced myofibroblast differentiation on femtosecond laser treated 316LS stainless steel

In-stent restenosis is a common complication after stent surgery which leads to a dangerous wall narrowing of a blood vessel. Laser assisted patterning is one of the effective methods to modify the stent surface to control cell–surface interactions which play a major role in the restenosis. In this current study, 316LS stainless steel substrates are structured by focusing a femtosecond laser beam down to a spot size of 50 μm. By altering the laser induced spot density three distinct surfaces (low density (LD), medium density (MD) and high density (HD)) were prepared. While such surfaces are composed of primary microstructures, due to fast melting and re-solidification by ultra-short laser pulses, nanofeatures are also observed as secondary structures. Following a detailed surface characterization (chemical and physical properties of the surface), we used a well-established co-culture assay of human microvascular endothelial cells and human fibroblasts to check the cell compatibility of the prepared surfaces. The surfaces were analyzed in terms of cell adherence, proliferation, cell morphology and the differentiation of the fibroblast into the myofibroblast, which is a process indicating a general fibrotic shift within a certain tissue. It is observed that myofibroblast proliferation decreases significantly on laser treated samples in comparison to non-treated ones. On the other hand endothelial cell proliferation is not affected by the surface topography which is composed of micro- and nanostructures. Such surfaces may be used to modify stent surfaces for prevention or at least reduction of restenosis.     

Derivative spectrophotometric determination of 5‐(hydroxymethyl)‐2‐furaldehyde (HMF) and furfural in Locust bean extract

Furfural and 5‐(hydroxymethyl)‐2‐furaldehyde (HMF) are useful indicators of accurate storage temperature of food samples. A first derivative spectrophotometric method was developed for the determination of the furfural and HMF level in Locust bean pekmez. In addition, the levels of the furfural and HMF were investigated during Locust bean pekmez preparation. The recoveries were generally nearly 100%. This method is also rapid and accurate and results in economical analyses of furaldehydes.     

A new nano-TiO2 immobilized biodegradable polymer with self-cleaning properties

This study concentrated on the direct immobilization of anatase nano titanium dioxide particles (TiO(2), 10nm particle size) into or onto a biodegradable polymer, polycaprolactone, by solvent-cast processes. The self-cleaning, namely photocatalytic properties of the produced materials were tested by photocatalytic removal of methylene blue as model compound and antimicrobial properties were investigated using Candida albicans as model microorganism. Produced TiO(2) immobilized polymer successfully removed methylene blue (MB, 1 × 10(-5)M) from aqueous solution without additional pH arrangement employing a UV-A light (365 nm) source. Almost 83.2% of dye was removed or decomposed by 5 wt% TiO(2) immobilized into PCL (0.08 g) and removal percentage reached to 94.2% with 5 wt% TiO(2) immobilized onto PCL after a 150 min exposure period. Although removal percentage decrease with increased ionic strength and usage of a visible light source, produced materials were still effective. TiO(2) immobilized onto PCL (5 wt%) was quite effective killing almost 54% of C. albicans (2 × 10(6)CFU/mL) after only 60 min exposure with a near visible light source. Control experiments employing PCL alone in the presence and absence of light were ineffective under the same condition.     

Derivative spectrophotometric determination of 5-(hydroxymethyl)-2-furaldehyde (HMF) and furfural in Locust bean extract

Furfural and 5-(hydroxymethyl)-2-furaldehyde (HMF) are useful indicators of accurate storage temperature of food samples. A first derivative spectrophotometric method was developed for the determination of the furfural and HMF level in Locust bean pekmez. In addition, the levels of the furfural and HMF were investigated during Locust bean pekmez preparation. The recoveries were generally nearly 100%. This method is also rapid and accurate and results in economical analyses of furaldehydes.     

Bi-criteria simulated annealing for the curriculum-based course timetabling problem with robustness approximation

Journal of Scheduling - In the process of developing a university’s weekly course timetable, changes in the data, such as the available time periods of professors or rooms, render the...     

A test apparatus to measure vertical wicking of fabrics – a case study on shirting fabrics

A test apparatus based on electrical conduction principle was designed and manufactured to overcome some difficulties and deficiencies in vertical wicking measurements of fabrics, which is one of the test methods used to determine liquid moisture transmission performance of fabrics. In order to test effectiveness of the apparatus, capillary time with regard to height was measured for woven shirting fabrics, which have different raw material, weave type and weft density. It was found that twill weave type and fabric looseness improved the wickability of fabrics. It was also revealed that raw material was an important factor for vertical wicking. The wicking rate of fabrics obtained from the new test apparatus correlated well with DIN 53924. Consequently, the test apparatus clearly demonstrated differences between the fabrics used in the study, and can be used to determine vertical wicking behaviour of fabrics.     

Heterogeneities in polyacrylamide gels immersed in acetone-water mixtures

Summary Immersion of polyacrylamide gels in acetone-water mixtures with a high content of acetone leads to the formation of heterogeneous structures. The extent of heterogeneity increases as the initial swelling degree of the gel increases, or, as the polarity of the nonsolvent decreases. The nature of the deswelling curves indicates that the polymer-rich regions of the gel formed by the collapse transition block the solvent diffusion outside the gel. This prevents the equilibration of the gel volume with surroundings. Received: 14 April 1998/Revised version: 17 June 1998/Accepted: 17 June 1998     

Comparative tear concentrations of topically applied ciprofloxacin, ofloxacin, and norfloxacin in human eyes

The tear pharmacokinetic profiles of 0.3% ciprofloxacin, 0.3% ofloxacin, and 0.3% norfloxacin ophthalmic solutions after a single drop topically administrations in the eyes of 30 healthy volunteers were evaluated. Tear samples collected at 30, 120, 180, and 240 minutes, were analyzed for drug concentrations by high performance liquid chromatography (HPLC) with fluorometric detection. Topically applied ciprofloxacin, ofloxacin, and norfloxacin achieved the mean tear concentrations (mean +/- SD) of 11.28 +/- 6.98, 6.52 +/- 4.06, and 13.28 +/- 8.78 micrograms/g at 30 min, and then fell to 3.52 +/- 1.30, 4.82 +/- 1.80, and 5.79 +/- 4.80 micrograms/g at 240 min, respectively. Topical norfloxacin achieved mean tear level significantly higher than ofloxacin at 30 min (p = 0.031). There were no statistically significant differences in the mean tear levels of ciprofloxacin versus ofloxacin (at 30, 120, 180, and 240 min), ciprofloxacin versus norfloxacin (at 30, 120, 180, and 240 min) and ofloxacin versus norfloxacin (at 120, 180, and 240 min). However, the mean tear levels, 240 min after dosing ciprofloxacin and norfloxacin, fell to the statistically significant concentrations (p = 0.02 and p = 0.01, respectively). But, it is concluded that concentrations of ciprofloxacin, ofloxacin, and norfloxacin in tears were still significantly greater than the minimum inhibitory concentrations for the most sensitive organisms, 240 min after a single drop application.