[Effect of tea on color change of silorane and methacrylate based composite resins]

At present, stainability and color instability of tooth-colored restorations following the consumption of colored beverages are among the problems commonly encountered in restorative dentistry. Filtek P90 composite resin comprising of Oxirane and Siloxane functional moieties was recently introduced aiming at reducing the polymerization shrinkage. The aim of this study was to evaluate the effect of tea on color change of P90 and Z250 composite resins using spectrophotometry. For this experimental study, 20 composite discs were fabricated in metal molds from Z250 and P90 composite resins and light cured using LED light-curing unit. Specimens were stored in distilled water at 37° C for 24 hours to allow completion of polymerization. Color of specimens was then measured at baseline and after 5 days of storage in water and tea solution using spectrophotometer. Data were analyzed using independent sample t-test and two-way ANOVA. The color change of P90 and Z250 composites after storage in distilled water was not significant in comparison to their baseline color [P>0.05]. However, both composite resins showed a significant change in color after storage in tea solution [P<0.05]. Stainability of Z250 composite in tea was significantly greater than that of P90; but in distilled water P90 showed greater color change than Z250. Within the limitations of this study, Z250 composite demonstrated significantly greater color change in comparison to P90 after immersion in tea solution

Performance of moving bed biofilm reactors for biological nitrogen compounds removal from wastewater by partial nitrification-denitrification process

In this research, the continuously operated laboratory scale Kaldnes [k1] moving bed biofilm reactors [MBBRs] under partial nitrification-denitrification process were used for treatment of synthetic wastewater containing ammonium and glucose. The Anoxic and Aerobic reactors were filled to 40 and 50% [v/v] to attach and retain biomass with k1 biofilm carriers, respectively. The favorite internal recycle ratio and hydraulic residence time [HRT] to eliminate nitrogen compounds were 300% of inflow rate and 20 hours, respectively. Optimal dissolved oxygen [DO] was 1-1.5 mg/L in the aerobic reactor. No sludge was returned into the system and only an internal recycling was performed from aerobic to anoxic reactor. The results showed that the maximum and average specific nitrification rate [SNR] in the aerobic reactor were 49.4 and 16.6 g NOx-N/KgVSS.day, respectively and the maximum and average specific denitrification rate [SDNR] as 156.8 and 40.1gNOx-N/KgVSS.day in the anoxic reactor, respectively. The results also showed that it is possible to reach a stable partial nitrification with high ratio of NO2-N/NOx-N [80% to 85%] during high load ammonium and low DO concentration [<1.5 mg/L] in the aerobic reactor. During optimum conditions, the average removal efficiency of total nitrogen [TN], ammonia and soluble organic carbon [SCOD] occurred as 98.23%, 99.75% and 99.4%, respectively. This study showed that the partial nitrification/denitrification process in the moving bed biofilm reactors system has an acceptable performance for treatment of wastewater with high load of organic carbon and organic nitrogen compounds

Spatial analysis of three agrichemicals in groundwater of isfahan using GS[+]

The purpose of this study was to undertake a spatial analysis of total organic carbon, electrical conductivity and nitrate, in order to produce a pollution dispersion and prediction map for the investigated area in the province of Isfahan in Iran. The groundwater samples were collected from a zone as a pilot study area of 80 km[2], including 25 water wells, based on the criteria of vulnerability assessment projects, that is, about one well per 3 km[2], during four seasons in 2008-09. In order to make any inferences about the areas that did not have well data, a statistical relationship between explanatory total organic carbon, electrical conductivity and nitrate variables related to well coordination was developed. The probability of the presence of elevated levels of the three compounds in the groundwater was predicted using the best-fit variogram model. According to spatial analysis, the highest R[2]=0.789 achieved was related to electrical conductivity and followed the exponential model with 0.266 for NO[3] [spherical model] and 0.322 for total organic carbon [exponential model] in the spring 2009. This showed the high confidence level for electrical conductivity dataset and forecasted trends. The results of the spatial analysis demonstrated that the transfer trends of electrical conductivity in the groundwater resources followed the route of groundwater movement in all seasons. However, for nitrate and total organic carbon, a definite trend was not obtained and pollution dispersion depended on many parameters

Selection of the most appropriate medium for assessing motility and DNA uptake of bovine spermatozoa

The aim of this study was to select the best medium to maintain sperm motility during sperm-DNA incubation and assess the DNA uptake by spermatozoa of Iranian Holstein bulls and its effects on sperm motility. Frozen sperms from an Iranian Holstein bull were thawed and centrifuged. Motile sperms were separated through Puresperm gradient [40/80%] followed by two times washing in SP-TALP medium. Then, sperms were washed once [PBS, Opti-MEM and SP-TALP] and incubated with DNA in each media followed by sperm motility estimation. The plasmid pEGFP-C1 was linearized and incubated with sperms at 37°C for 1 hour. Sperm-DNA mixture was treated with DNase I and the sperm pellet was washed with PBS. DNA extraction from sperms and supernatants from the last washing were used as template for PCR. Data was analyzed using SAS package and mean comparisons between sperm motility in different media were performed. Sperm motility after incubation in PBS, Opti-MEM and SP-TALP were 40[ +/- 2.89], 2[ +/- 1.53] and 54[ +/- 4.41] percent, respectively. PCR results from transfected sperms indicated that EGFP transgene internalized into the bovine sperms and DNaseI treatment could not eliminate it. In conclusion the best medium for sperm and DNA incubation was SPTALP. The DNA not only could attach to the post acrosomal region of spermatozoa but also could integrate into it. So bovine spermatozoa can be used as transgene carrier into oocyte

[In vitro development of cattle embryo as affected by glucose, serum and EDTA]

The aim of this study was to evaluate the effect of different modifications of sequential synthetic oviductal_fluid [SOF] culture system on developmental competence of in vitro matured/fertilized cattle embryos. Bovine oocytes were matured and fertilized in vitro and then presumptive zygotes were randomly cultured for up to 9 days in different modifications of SOF culture system to consider the effects of glucose, serum and EDTA on embryo development. All the embryo culture systems were efficient to support bovine embryo development till blastocyst stage. There was no significant difference in the ratios of embryos; however, the ratios of blastocyst and also hatchability of embryos cultured in SOF C [51.3%, 43.0% and 83.8%, respectively] were significantly higher than those of all the other SOF groups. Furthermore, while glucose had a partial improving effect on embryo development, a significant decrease in embryo development beyond the morula stage was observed in embryos cultured in SOF system with initial supplementation of EDTA compared with all the other groups. It was concluded that appropriate modifications of SOF culture systems can result in significantly great in vitro embryo development

[Effect of demecolicne treatment on the developmental competency of in vitro matured bovine oocytes]

The aim of this study was to investigate whether demecolicne treatment of matured bovine oocytes adversely affects the process of in vitro fertilization and embryo development. Bovine Cumulus Oocyte Complexes [COC's] were matured in vitro and then were randomly allocated to two treatment groups of common concentrations of demecolicne [0.05 and 0.4 micro g/ml for 30 min] and a control group. COC's were then fertilized and cultured in vitro for up to 9 days when the ratios of in vitro embryo development and the viability of the hatched blastocysts were assessed and compared with the control group [p<0.05]. The ratios of the cleavage and blastocyst formation of demecolicne treated groups [0.4 and 0.05 micro g/ml] were 68.6, 63.5% and 23.3, 32.8%, which were not significantly different from the control group [73.3, 29.0%], respectively. The results of cell-viability were also not significantly different between the control vs. treatment groups. Since the overall indices of in vitro embryo development revealed no significant difference between the demecolicne treated compared to control bovine oocytes, it seems that demecolicne treatment of matured bovine oocytes may not compromise their potency for further in vitro development