The Effect of Coloring Beverages on Color Stability of Hybrid Ceramics with Different Surface Treatments

Objective: To assess the effects of coloring beverages on the color stability of two types of hybrid ceramics with different surface treatments. Material and Methods: 180 specimens of two hybrid ceramics (Vita Enamic and Mazic Duro) and a feldspathic ceramic (Vita Mark II) were prepared (n=60 in each group). Half of the discs in each group were glazed while the other was polished. The specimens were then divided into three subgroups and immersed in distilled water, carrot juice, and coffee. The overall color difference (∆E) was calculated based on CIE L*a*b* color space. Data were analyzed using three-way and one-way ANOVA; Tukey’s honest significant difference was also done for pairwise comparisons (α=0.05). Results: Vita Mark II specimens revealed less overall color changes compared to other groups. The ∆E of the glazed Vita Enamic specimens was greater than polished specimens following immersion in distilled water (p=0.03) and coffee (p=0.001), but it was not significant for carrot juice. The same results were obtained for polished Mazic Duro specimens. Relatively similar amounts of ∆E were recorded in polished and glazed subgroups of Vita Mark II. Conclusion: The ∆E of hybrid ceramics was higher than Vita Mark II. Polishing could be recommended for surface treatment of hybrid ceramics instead of glazing, saving time and facilitating the process

A Two-Stage DEA to Analyze the Effect of Entrance Deregulation on Iranian Insurers: A Robust Approach

We use two-stage data envelopment analysis (DEA) model to analyze the effects of entrance deregulation on the efficiency in the Iranian insurance market. In the first stage, we propose a robust optimization approach in order to overcome the sensitivity of DEA results to any uncertainty in the output parameters. Hence, the efficiency of each ongoing insurer is estimated using our proposed robust DEA model. The insurers are then ranked based on their relative efficiency scores for an eight-year period from 2003 to 2010. In the second stage, a comprehensive statistical analysis using generalized estimating equations (GEE) is conducted to analyze some other factors which could possibly affect the efficiency scores. The first results from DEA model indicate a decline in efficiency over the entrance deregulation period while further statistical analysis confirms that the solvency ignorance which is a widespread paradigm among state owned companies is one of the main drivers of efficiency in the Iranian insurance market

Some classes of perfect strongly annihilating-ideal graphs associated with commutative rings

summary:Let $R$ be a commutative ring with identity and $A(R)$ be the set of ideals with nonzero annihilator. The strongly annihilating-ideal graph of $R$ is defined as the graph ${\rm SAG}(R)$ with the vertex set $A(R)^*=A(R)\setminus\{0\}$ and two distinct vertices $I$ and $J$ are adjacent if and only if $I\cap {\rm Ann}(J)\neq (0)$ and $J\cap {\rm Ann}(I)\neq (0)$. In this paper, the perfectness of ${\rm SAG}(R)$ for some classes of rings $R$ is investigated

Lotus effect optimization algorithm (LEA): a lotus nature-inspired algorithm for engineering design optimization

Here we introduce a new evolutionary algorithm called the Lotus Effect Algorithm, which combines efficient operators from the dragonfly algorithm, such as the movement of dragonflies in flower pollination for exploration, with the self-cleaning feature of water on flower leaves known as the lotus effect, for extraction and local search operations. The authors compared this method to other improved versions of the dragonfly algorithm using standard benchmark functions, and it outperformed all other methods according to Fredman\u27s test on 29 benchmark functions. The article also highlights the practical application of LEA in reducing energy consumption in IoT nodes through clustering, resulting in increased packet delivery ratio and network lifetime. Additionally, the performance of the proposed method was tested on real-world problems with multiple constraints, such as the welded beam design optimization problem and the speed-reducer problem applied in a gearbox, and the results showed that LEA performs better than other methods in terms of accuracy

Model identification and dynamic analysis of ship propulsion shaft lines

Dynamic response analysis of mechanical structures is usually performed by adopting numerical/analytical models. Finite element (FE) modeling as a numerical approach plays an important role in dynamic response analysis of complex structures. The calculated dynamic responses from FE analysis are only reliable if accurate FE models are used. There are many elements in real mechanical structures which make constructing accurate FE models difficult. For example, modeling the boundary supports of mechanical structures are usually challenging because of the uncertainties existing in their stiffness values. The stiffness values of boundary supports can be identified by using experimental natural frequencies and hence the FE model can be corrected. In this paper, the FE modeling and updating of propulsion shaft lines in a ship structure is considered by employing experimental modal parameters, i.e. natural frequencies. Natural frequencies of shaft lines are measured by performing experimental vibration testing. The corrected FE models are used and dynamic response analysis of shaft lines is conducte

Genotyping of Virulence Factors of Uropathogenic Escherichia coli by PCR

Background: Escherichia coli is the most causative agent of urinary tract infections (UTIs). Apart from all human infectious diseases, UTI have a high prevalence and in most cases, Escherichia coli is a dominance bacterium which can cause pyelonephritis and cystitis. The aim of the study was to determine the occurrence of some virulence genes expressing fimbriae, production of hemolysin and aerobactin among a hundred Escherichia coli isolates obtained from in-and outpatients of Karaj Shahid Rajaii hospital, showing clinical and laboratory signs of UTI.Materials and Methods: In this investigation we isolated Escherichia coli strains from urine samples of patients with UTI during the period of July to December 2012 and studied them for the presence of the virulence genes by PCR.Results and Conclusion: The most abundant virulence factor in this study was fimH. The prevalence of the virulence factors for fimbriae type 1 (fimH gene), pyelonephritis associated pili (pap gene), S-family adhesions (sfa gene), hemolysin (hly gene) and aerobactin (aer gene), was 73%, 46%, 32%, 47%, 57%, respectively

Homology modeling and molecular dynamics simulation of odonthubuthus doriae (Od1) scorpion toxin in comparison to the BmK M1

All of the α-subgroups share similarity in their sequence and structure but different in the toxicity to various voltage-gated sodium channels (VGSCs). We modeled the first 3D structural model of the Od1 based on BmK M1 using homology modeling. The reliability of model for more investigation and compare to BmK M1 has been examined and confirmed. Then the model structure is further refined by energy minimization and molecular dynamics methods. The purpose of this modeling and simulation is comparison toxicity of two mentioned toxins by investigation structural feature of functional regions including core domain, 5-turn and C-terminal which make NC domain. In the one hand, it is intriguing that Od1 in comparison to BmK M1 shows same solvent accessible surface area (SASA) in 5-turn region but a little more exposed and feasibility (more SASA) in C-terminal region and key functional residues of C-terminal such as positive residues Arg58, lys62 and Arg (His)64. These data suggested that Od1 has similarity with BmK M1 but has more toxicity to sodium channel. In the other hand 5-turn proximity of C-terminal to 5-turn in BmK M1with cis peptide bond is less than Od1 without cis peptide bond which is a confirmation with experimental data about BmK M1.A better understanding of the 3-D structure of Od1and comparison to BmK M1 will be helpful for more investigation of functional characters action of natural toxins with a specialized role for VGSCs

Multiparasitism of stink bug eggs: competitive interactions between Ooencyrtus pityocampae and Trissolcus agriope

Females of Trissolcus agriope (Platygastridae) avoid host (Brachynema signatum) eggs parasitized by conspecifics or Ooencyrtus pityocampae (Encyrtidae), but females of the latter species will superparasitize and multiparasitize, although they mostly attack unparasitized eggs. Females of T. agriope were more efficient in the laboratory and parasitized more hosts in 24 and 48 h. In multiparasitized hosts, O. pityocampae was a superior larval competitor and could complete also development as a facultative hyperparasitoid. When females of both species foraged together, T. agriope parasitized significantly more than O. pityocampae, about 50%in both cases, although O. pityocampae almost doubled its parasitism rate as the exposure period was lengthened from 24 h to 48 h. When O. pityocampae followed T. agriope in sequential foraging bouts, the former species successfully parasitized more hosts than the latter. The advisability of co-releases of both species to improve biological control of first generation B. signatum in Iranian pistachio orchards is discussed.Citation: Mohammadpour, M., Jalali, M. A., Michaud, J. P., Ziaaddini, M., & Hashemirad, H. (2014). Multiparasitism of stink bug eggs: Competitive interactions between Ooencyrtus pityocampae and Trissolcus agriope. Retrieved from http://krex.ksu.ed

The protective effect of vitamin E on rats’ ovarian follicles following an administration of diazinon: An experimental study

Background: Diazinon (DZN) is an organophosphate insecticide that has been widely utilized in agriculture all over the world and caused many negative effects on different species such as plants and animal species, especially on a human. Objective: The aim of the present study was to evaluate the protective effect of vitamin E on rats’ ovarian follicles following an administration of diazinon. Materials and Methods: A total of 30 adult female Wistar rats were divided into five groups: a control group (without any intervention), sham group (received only pure olive oil, as solvent), experimental group I (DZN+olive oil, 60 mg/kg), experimental group II (vitamin E, 200 mg/kg), and experimental group III (DZN: 60 mg/kg+vitamin E: 200 mg/kg). All drugs were injected intraperitoneally, except vitamin E which was administrated by gavage. The animals were sacrificed after two weeks and the left ovary was used to measure proliferation of ovarian follicles. Tissues were analyzed by the PCNA technique and viewed with an optical microscope for evaluating cell proliferation. Results: The result of the present study revealed that the number of proliferative cells in the experimental group I decreased significantly in contrast to the control group in secondary and Graffian follicles (p< 0.001). The administration of vitamin E plus DZN significantly increased proliferative cells compared to the DZN group (p< 0.001). Primordial follicles showed that all study groups were lacking PCNA positive cells, which means no expression of PCNA in these follicles. The results of this study showed that primary follicles in all study groups had a few and scattered PCNA positive cells with no significant difference between the groups (p> 0.05). Conclusion: Results showed that DZN reduced proliferation in secondary and Graffian follicles and vitamin E increased it. The results of this study suggested that vitamin E by its antioxidant activity was able to improve the DZN-induced ovarian toxicity. Key words: Diazinon, Proliferation, Ovary, Vitamin E, Rat