Sorption of platinum on immobilized microorganisms for its on-line preconcentration and chemiluminescent determination in water samples

Fungi of the type Aspergillus sp. were immobilized on a cellulosic resin and used as a biosorbent for the on-line preconcentration and separation of Pt(IV) ions prior to their chemiluminescent determination via flow injection analysis. Biosorption and elution conditions were optimized, and the results compared to biosorbents based on the use of Chlorella vulgaris algae and Saccharomyces cerevisiae yeast in terms of preconcentration and selective retention of Pt(IV). The immobilized fungi presented here have a high potential for use in platinum biosorption. The procedure exhibits the currently lowest limit of detection (0.02 ng mL−1 of Pt) and very high selectivity. The procedure was applied to the determination of Pt(IV) in river water, road run-off, and wastewater samples

The influence of argumentation on understanding nature of science

The aim in conducting this study is to explore the effects of argumentation on pre-service science teachers’ views of the nature of science. This study used a qualitative case study and conducted with 20 pre-service science teachers. Data sources include an open-ended questionnaire and audio-taped interviews. According to pretest and posttest scores, 3 participants were selected for gathering qualitative data and follow-up interviews. Analyses of the findings revealed that the argumentation based instruction was effective in 2 of 3 participants’ views of the nature of science. According to the results, 2 aspects of the nature of science were the most developed aspects of the nature of science assessed in this study; the social and cultural and the creative and imaginative nature of science. These findings highlight the need for teacher preparation programs to incorporate argumentation based instruction that promotes the development of the nature of science views. © Author(s)

Mineral contents of some wild ascomycetous mushrooms

WOS:000312621400120Minerals (Al, B, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sn and Zn) contents of eight naturally growing ascomycetous mushrooms (Geopora arenicola, Geopora sumneriana, Helvella acetabalum, Helvella leucomelaena, Helvetia leucopus, Mitmphora semilibera, Morchella elata and Morchella rigida) and the underlying soil samples, were determined by inductively coupled plasma optical emission spectroscopy (ICP-OES). In general, mineral contents of the fruit bodies are lower than the substrate soil, but Cd, Cu and Zn accumulation were found to be higher than the underlying soil in some mushrooms

Clinical Evaluation of Silorane and Nano-hybrid Resin Composite Restorations in Class II Cavities up to 3 Years

In this study, the clinical performance of a silorane-based resin composite (SC) vs a nano-hybrid resin composite (NHC) was evaluated in Class II cavities. From January 2012 to February 2013, a total of 29 patients (eight men, 21 women; mean age, 24 ± 5 years) received 29 pairs of restorations using both SC (Filtek Silorane, 3M ESPE) and NHC (Filtek Z550, 3M ESPE) materials. Patients were followed until February 2015. One operator performed all restorations using the corresponding adhesive resins according to the manufacturers' instructions. Two calibrated independent examiners evaluated the restorations at one week, six months, and then annually using the modified United States Public Health Service (USPHS) criteria for anatomic form, marginal adaptation, color match, surface roughness, marginal discoloration, secondary caries, and postoperative sensitivity. Changes in the USPHS parameters were analyzed with the McNemar test (α=0.05). The mean observation period was 31.2 months. Marginal adaptation was the only parameter that showed a significant difference and was worse for SC than NHC (p=0.012). At the final recall, 17 restorations from the SC group and five from the NHC group received a score of 1 (explorer catches). These scores were significantly different between baseline and final recall for SC (p0.05). Both NHC and SC performed similarly in Class II restorations up to three years except for marginal adaptation, for which the latter demonstrated significant deterioration at the final recall compared with baseline

Clinical Performance of Nanofilled and Microhybrid Direct Composite Restorations on Endodontically Treated Teeth

This study evaluated the clinical performance of direct restorations made of nanofilled and microhybrid resin composites in endodontically treated teeth. Twenty patients (11 males, 9 females; mean age: 34.2±10) that met the inclusion criteria received a total of 48 restorations. After employing etch-and-rinse adhesive system, one dentist placed all restorations using either a nanofilled (Filtek Ultimate) or microhybrid (Filtek Z250) resin composite. The restorations were clinically reviewed at baseline, 6 months, and up to 2 years using the modified United States Public Health Service (USPHS) criteria. The changes were analyzed using the McNemar test and marginal homogeneity tests (p⟨0.05). The mean observation period was 17.4 months. With respect to color match, marginal adaptation, secondary caries, and surface texture, no significant differences were found between the two restorative materials (p⟩0.05). Most restorations yielded alpha or bravo scores with respect to the evaluation criteria. Five restorations failed due to chipping up to 2 years (1 microhybrid at 6 m, and 3 at 2 years; 1 nanofilled at 2 y) and were repaired. One complete replacement and one extraction due to endodontic complications were needed for 2 microhybrid resin group at 2 years

Factors Affecting Brucella

Brucella infections have a wide spectrum of symptoms especially in children, making the diagnosis a complicated process. The gold standard for the final diagnosis for brucellosis is to identify the Brucella spp. isolated from blood or bone marrow cultures. The main purpose of this work was to evaluate the factors affecting the isolation of Brucella spp. from blood cultures. In our study, the ratio of fever, presence of hepatomegaly, and splenomegaly were found to be higher in the bacteremic group. In addition, C-reactive protein levels and liver function enzymes were found to be higher in the bacteremic group. In our opinion, while evaluating the febrile child with suspected Brucella infection, we highly recommend sampling blood cultures regardless of the history of previous antimicrobial therapy and duration of the symptoms