Influence of short-fiber composite base on fracture behavior of direct and indirect restorations.

OBJECTIVES: The aim was to examine the influence of short-fiber composite (SFC) core on the fracture-behavior of different types of indirect posterior restorations. In addition, the effect of thickness ratio of SFC-core to the thickness of the veneering conventional composite (PFC) on fracture-behavior of bi-structured composite restorations was evaluated. MATERIALS AND METHODS: MOD cavities with removed palatal cusps were prepared on 90 intact molars. Five groups of direct overlay restorations (n = 10/group) were fabricated having a SFC-core (everX Flow) with various thicknesses (0, 1, 2, 3, 4 mm) and layer of surface PFC (G-aenial Anterior), remaining the thickness of the bi-structure restoration to be 5 mm. Four groups of CAD/CAM-made restorations (Cerasmart 270 and e-max CAD) were fabricated either with 2-mm layer of SFC-core or without fiber reinforcement. Intact teeth (n = 10) were used as control group. Restorations were statically loaded until fracture. Fracture patterns were evaluated visually. Data were analyzed using ANOVA (p = 0.05). RESULTS: With indirect overlay restorations, no statistically significant differences (p > 0.05) were observed in the load-bearing capacities between restorations reinforced by 2-mm SFC-core (bi-structured) and those fabricated from plain restorative materials. ANOVA displayed that direct overlay restorations made from 4-mm layer thickness of SFC-core had significantly higher load-bearing capacities (3050 ± 574 N) (p < 0.05) among all the groups tested. CONCLUSIONS: Restorations (direct/indirect) combining SFC-core and a surface layer of conventional material demonstrated encouraging achievement in reference to fracture behavior. CLINICAL RELEVANCE: The use of flowable short-fiber composite as reinforcing base with large direct and indirect restorations may result in more repairable failure.

Retrospective evaluation of adult poisoning cases admitted to emergency department of a University Hospital in Turkey.

OBJECTIVE: We aimed to evaluate demographic, etiological, clinical features, and prognosis of poisoning cases applied to a tertiary emergency department retrospectively. MATERIALS AND METHODS: The recordings of poisoning cases aged 18 years old and over which applied to the department of emergency medicine between the dates of 2010-2015 were examined. Age, gender, admission date, amount of time passed since exposure to the poisonous substance, application method, cause of poisoning, laboratory findings at arrival, vital signs, type of poisonous substance, the way of taking, treatment method in urgent care, consultation need, and the outcome of cases were recorded. RESULTS: Of the poisoning cases, 437 (52.1%) were female, and 402 (47.9%) were male. The mean age was calculated as 33.50. When the cause of poisonings are examined; 456 patients were found to be poisoned by a suicide attempt, 350 were accidentally poisoned, and 33 were poisoned by treatment complication. As the causing substance of poisoning, medicinal drugs were found in 465 cases (55.4%), carbon monoxide in 205 cases (24.4%), and narcotics in 119 cases (14.2%). Of medicinal drug poisonings, 221 (46.8%) were multiple drug intake. It was seen that 46.6% of the patients were kept under observation with only symptomatic treatment while nasogastric lavage and activated charcoal were applied in 40.2% of them. CONCLUSION: It can be suggested that poisonings are encountered more commonly in young people, especially in women, with medicinal drugs and for suicidal purposes. Drugs detected at high rates in poisonings, such as painkillers and antidepressants, should be used more cautiously.

Studies on immobilization of urease in gelatin by cross-linking.

Urease enzyme was immobilized in photographic gelatin by chemical cross-linking using formaldehyde, glutaraldehyde and chromium (III) acetate. The effects of enzyme and cross-linker concentrations, temperature, incubation time and pH on urea hydrolysis were investigated. Effect of reuse on the activity of immobilized enzyme was also studied. Glutaraldehyde (0.004 M) was the most suitable cross-linker; relative activities within 2.5 months after 24 reuses were stable (about 78%).

Immobilization of alpha-amylase into photographic gelatin by chemical cross-linking.

alpha-Amylase was immobilized into photographic gelatin by chemical cross-linking with chromium (III) acetate and chromium (III) sulphate. Cellulose triacetate film strips, enabled simple handling when coated with an alpha-amylase-gelatin mixture, accomplishing a high degree of durability during consecutive immersions into reaction media. The optimum conditions for pH, substrate concentration, temperature, incubation time and storing conditions of free and immobilized alpha-amylase were determined. The effect of use number on activity and the effect of resting on reuse number were also determined. Photographic gelatin was found to be a very efficient natural polymer, due to its extraordinary diffusion characteristics for immobilization as a carrier.

Effect of chromium salts on invertase immobilization onto carboxymethyl-cellulose-gelatine carrier system.

The carboxymethylcellulose-gelatine carrier system was investigated for invertase immobilization. Chromium (III) acetate, chromium (III) sulphate and potassium chromium (III) sulphate were used as cross-linking agents. Effect of carboxymethylcellulose-gelatine ratio and cross-linker concentration on immobilized enzyme activity were analysed. Reusability of immobilized enzyme was also investigated. Maximum immobilized enzyme activities were obtained with cross-linkers chromium (III) sulphate (0.004 mol dm-3) and potassium chromium (III) sulphate (0.001 mol dm-3) for a carrier composition of carboxymethylcellulose-gelatine ratio 0.111 (w/w) as 78%.

Stability and storage conditions of NADH-cytochrome b5 reductase cross-linked into gelatin by chromium (III) acetate.

NADH-cytochrome b5 reductase was isolated and partially purified from rabbit liver microsomes. It was immobilized into gelatin by chemical cross-linking. Chromium (III) acetate was used as cross-linker. The effects of pH and temperature on the immobilized cytochrome b5 reductase were investigated. The reusability and storage stability of immobilized enzyme were also tested. Immobilized NADH-cytochrome b5 reductase activities were found to be stable for at least 72 d and 24 uses. The storage stability of NADH-cytochrome b5 reductase was improved with immobilization at 25 degrees C.

Separation and determination of rare earth elements by Dowex 2-X8 resin using sodium trimetaphosphate as elution agent.

The distribution coefficients of rare earth elements and thorium with Dowex 2-X8, 200-400 mesh, a strongly basic anion-exchange resin, have been determined regarding four different concentrations of sodium trimetaphosphate (3 x 10(-3), 5 x 10(-3), 7 x 10(-3) and 0.01 M). The separation of the rare earths and thorium obtained from an Australian monazite has been investigated by anion-exchange chromatography with sodium trimetaphosphate concentration gradient on a Dowex 2-X8 ion-exchange columns. The order of elution of the elements was the reverse of the order of elution of the same elements on Dowex 1 resin. The elution was investigated using 5 mg and 250 mg samples. In the separation of 5 mg samples, all elements were separated in 29 min. It has been seen that the elution peaks are narrow, tailing effects are very small, Dy and Y are well separated. Qualitative and quantitative determinations were realized by spectrofluorometry.

Third order derivative spectrophotometric determination of ascorbic acid in fruits and vegetables.

Ascorbic acid (AA) has been determined in kiwi, parsley and grapefruit by third order derivative spectrophotometry without using any separation or background correction techniques and reagents. The method is based on the measurement of the distances between two extremum values (peak-to-peak amplitudes) in the third order derivative spectra of the extracts. A metaphosphoric acid (3% w/v)-acetic acid (8% v/v) mixture was found to be the most suitable extraction solution. In the third order derivative spectrum, the extrema of 259.4 nm and 276.2 nm were used for the quantitative determination of AA in kiwi, and the extrema of 227 nm and 237 nm were used for the quantitative determination of AA in parsley and grapefruit. Calibration curves were constructed for the 2.0-10.0 mug ml(-1) concentration range. Relative standard deviations were calculated from the assay results of 14 samples. They were found to be in the ranges of 0.53-2.45% and 0.50-1.41% for the proposed method and the Association of Official Analytical Chemists (AOAC) method, respectively. The obtained results were statistically compared with those of the official method of AOAC using the F test. There was no significant difference between the precisions at a 95% confidence level.

Spectrofluorimetric determination of Er (III) with diantipyrylmethane.

The optimum fluorescence conditions for erbium (III) are obtained by irradiating this lanthanide at 435 nm in 0.04 microg ml(-1) diantipyrylmethane solution at pH = 8 (lambdaem = 510 nm). The method proposed is satisfactory for the determination of erbium (III) in the range of 0.001 to 1 microg ml(-1). The relative standard deviation 0.02 microg ml(-1) Er (III) in 0.04 microg ml(-1) diantipyrylmethane solution is 1.1%. The effect of other rare earths upon the intensity of the fluorescence emitted by erbium (III) is discussed.

The stability constants of the rare earth complexes with trimetaphosphoric acid.

The stability constants of the complexes formed between the rare earth metal ions and the anion of trimetaphosphoric acid have been determined at a temperature of 20 degrees C and an ionic strength of mu = 0.1 by the ion-exchange equilibrium method. The investigations indicate that stabilities of complexes increased from La to Lu. The highest and the lowest stability constant values (beta) were found to be 7.76 and 3.82 for Lu3+ and La3+ respectively.

Investigation of Bisphenol A as an endocrine disruptor, total thiol, malondialdehyde, and C-reactive protein levels in chronic obstructive pulmonary disease.

OBJECTIVE: Chronic obstructive pulmonary disease (COPD) is a common health problem and it is associated with oxidant/antioxidant imbalance and systemic inflammation. Bisphenol A (BPA) is an endocrine disruptor agent, exerting a wide variety of metabolic effects. Also, BPA is related with oxidative stress, decreased antioxidant enzymes, and inflammation. The aim of this study is to investigate the relationships between COPD and serum BPA, C-reactive protein (CRP), malondialdehyde (MDA), and total thiol levels. PATIENTS AND METHODS: This study was enrolled at 83 subjects that they were divided into two groups: control (n=33), COPD (n=50). The serum BPA, CRP, MDA, and total thiol levels were analyzed. RESULTS: The CRP and BPA levels were significantly higher in the COPD patients than control subjects. The total thiol levels were significantly lower in COPD cases than the controls. There is no different between groups for MDA. Also, there had a linear relationship between BPA and CRP in correlation analysis. CONCLUSIONS: COPD is associated with high serum BPA, CRP and low total thiol levels in comparison with healthy individuals. It is suggested that BPA might have a role in the etiopathogenesis of COPD.

Investigations on drug release systems using CMC crosslinked with ferric ions.

A drug delivery system with controlled release capability was developed by crosslinking carboxymethylcellulose with ferric ions. Erythromycin was used as model drug throughout the research. It was aimed to transport model drug through gastro intestinal track with minimal release up to intestines. Different techniques were applied to obtain a suitable delivery system and finally minimal release (10% of the total) in stomach (simulated by pH 2.0) and a high release (90% of the total) in intestinal systems (simulated by pH 7.5) was obtained by applying a combination of wet and dry coating, drying and secondary crosslinking.

Determination of some beta-blockers as dabsyl derivatives by HPLC.

A HPLC method has been developed that permits the sensitive determination of beta adrenergic blocking drugs, including acebutolol, metoprolol, oxprenolol, pindolol, and propranolol. These compounds were converted to their chromophoric dabsyl derivatives and were separated by a reversed phase chromatographic column (mu-Bondapak C18) with methanol-water (75:25) as isocratic mobile phase. The derivatives were detected by a variable wavelength detector operating at 430 nm. The method was applied to commercial pharmaceutical preparations and the results were statistically compared with those obtained by official methods using t- and F-tests.