The use of functionally graded dental crowns to improve biocompatibility: a finite element analysis

In post-core crown restorations, the significant mismatch between stiffness of artificial crowns and dental tissues leads to stress concentration at the interfaces. The aim of the present study was to reduce the destructive stresses by using a class of inhomogeneous materials called functionally graded materials (FGMs). For the purpose of the study, a 3-dimentional computer model of a premolar tooth and its surrounding tissues were generated. A post-core crown restoration with various crown materials, homogenous and FGM materials, were simulated and analyzed by finite element method. Finite element and statistical analysis showed that, in case of oblique loading, a significant difference (p < 0.05) was found at the maximum von Mises stresses of the crown margin between FGM and homogeneous crowns. The maximum von Mises stresses of the crown margin generated by FGM crowns were lower than those generated by homogenous crowns (70.8 vs. 46.3 MPa) and alumina crown resulted in the highest von Mises stress at the crown margin (77.7 MPa). Crown materials of high modulus of elasticity produced high stresses at the cervical region. FGM crowns may reduce the stress concentration at the cervical margins and consequently reduce the possibility of fracture.     

Antiproliferative activity of morpholine-based compounds on MCF-7 breast cancer,colon carcinoma C26, and normal fibroblast NIH-3T3 cell lines and study of their binding affinity to calf thymus-DNA and bovine serum albumin

Abstract

This report describes the results of a study on the antiproliferative activity of the morpholine-based ligand 1,3-bis(1-morpholinothiocarbonyl)benzene (HL) and its nickel(II) complex (NiL) against human breast cancer cells (MCF-7), colon carcinoma cells (C26), and normal fibroblast NIH-3T3 cells. NiL showed better cytotoxicity on both cancerous cells relative to normal cells in vitro with the highest selective index of 2.22 in MCF-7 cells. The interaction of both compounds with calf thymus DNA (CT DNA) and bovine serum albumin (BSA) was studied using various spectroscopic techniques and analytical methods such as UV???vis titrations, thermal denaturation, circular dichroism, competitive fluorescent intercalator displacement assays, as well as molecular modeling. The fluorescence intensity of the probe molecule increases clearly when HL and NiL are added to the methylene blue (MB)–DNA system. Furthermore, the binding of HL and NiL quenches the BSA fluorescence, revealing a 1:1 interaction with a binding constant of about 10⁵?M^?1.

Communicated by Ramaswamy H. Sarma     

In Vitro Interaction of Geldanamycin with Triazoles and Echinocandins Against Common and Emerging Candida Species

Mycopathologia - The aim of this study was to determine the in vitro interactions of geldanamycin (Hsp90-inhibitor) with triazoles and echinocandins against common and emerging Candida species....     

The measurement of ecstasy in human hair by triple phase directly suspended droplet microextraction prior to HPLC-DAD analysis

New pre-concentration technique, triple phase suspended droplet microextraction (SD-LPME) and liquid chromatography-photodiode array detection was applied to determine ecstasy, MDMA (3,4-methylendioxy-N-methylamphetamine) in hair samples. In this research MDMA in hair was digested and after treatment extracted. The effective parameters were investigated and method was evaluated. Under the optimal conditions, the MDMA was enriched by factor 98.11. Linearity (r = 0.9921), was obtained in the range of 10–15,000 ng mL^?1 and detection limit was 0.1 ng mL^?1.     

Varied tolerance to NaCl salinity is related to biochemical changes in two contrasting lettuce genotypes

Salt stress perturbs a multitude of physiological processes such as photosynthesis and growth. To understand the biochemical changes associated with physiological and cellular adaptations to salinity, two lettuce varieties (Verte and Romaine) were grown in a hydroponics culture system supplemented with 0, 100 or 200 mM NaCl. Verte displayed better growth under 100 mM NaCl compared to Romaine, but both genotypes registered relatively similar reductions in growth under 200 mM NaCl treatment. Both varieties showed differences in net photosynthetic activity in the absence of salt and 8 days after salt treatment. These differences diminished subsequently under prolonged salt stress (14 days). Verte showed enhanced leaf proline and restricted total cations especially Na⁺, lesser malondialdehyde (MDA) formation and lignification in the roots under 100 mM NaCl salinity. Membrane damage estimated by electrolyte leakage increased with elevated salt concentrations in roots of both varieties, but Verte had significantly lower electrolyte leakage relative to Romaine under 100 mM NaCl. Moreover, Verte also accumulated greater levels of carotenoids under increasing NaCl concentrations compared to Romaine. Taken together, these findings suggest that the greater tolerance of Verte to 100 mM NaCl is related to the more restricted accumulation of total cations and toxic Na⁺ in the roots and enhanced levels of antioxidative metabolites in root and leaf tissue.     

Sericin modulates learning and memory behaviors by tuning of antioxidant,inflammatory, and apoptotic markers in the hippocampus of aged mice

Molecular Biology Reports - Sericin is a protein derived from silkworm cocoons and identified as an anti-aging agent. This study aimed to examine the effects of sericin administration on episodic...     

Protective effect of Zizyphus lotus jujube fruits against cypermethrin-induced oxidative stress and neurotoxicity in mice

Context: Cypermethrin (CYP) is a synthetic pyrethroid insecticide used worldwide in agriculture, home pest control. The toxicity of CYP is well studied in many organisms.

Objective: The aim of present study was to investigate the protective effect of Zizyphus lotus (Zizyp) fruit against neurotoxicity and oxidative stress induced by CYP in mice.

Materials and methods: Mice were divided into four groups of six each: groups I and II were used as control and CYP control (20?mg/kg body weight). While, groups III was orally treated with Zizyphus lotus fruit (5?g/kg body weight) plus CYP (20?mg/kg body weight) for 18?days. Furthermore, HPLC–ESI–MS–MS (Q-Tof) and GC–MS were used to identify the compounds fraction.

Results: Antioxidant enzyme catalase (CAT), neurotoxicity enzyme acetylcholinesterase (AChE) activities and hydrogen peroxide (H₂O₂)_, malondialdehyde (MDA) levels were determined in the liver, kidney and heart. CYP caused decreased CAT activity, inhibition of AChE activity and increased the levels of H₂O₂ and MDA in heart, liver and kidney.

Conclusion: Our results indicate that Zizyp fruit is markedly effective in protecting mice against CYP-induced biochemical changes. This protection may be due to its antioxidant property and scavenging ability against active free radicals.     

Genetically modified crops and small-scale farmers: main opportunities and challenges

Although some important features of genetically modified (GM) crops such as insect resistance, herbicide tolerance, and drought tolerance might seem to be beneficial for small-scale farmers, the adoption of GM technology by smallholders is still slight. Identifying pros and cons of using this technology is important to understand the impacts of GM crops on these farmers. This article reviews the main opportunities and challenges of GM crops for small-scale farmers in developing countries. The most significant advantages of GM crops include being independent to farm size, environment protection, improvement of occupational health issues, and the potential of bio-fortified crops to reduce malnutrition. Challenges faced by small-scale farmers for adoption of GM crops comprise availability and accessibility of GM crop seeds, seed dissemination and price, and the lack of adequate information. In addition, R&D and production costs in using GM crops make it difficult for these farmers to adopt the use of these crops. Moreover, intellectual property right regulations may deprive resource poor farmers from the advantages of GM technology. Finally, concerns on socio-economic and environment safety issues are also addressed in this paper.     

T helper cells subtypes and their cytokine gene expression affected by carvacrol in sensitized mice administered during sensitization period

Th1, Th2, Th17, and Treg cells and their cytokine gene expressions in splenocytes of control mice, ovalbumin sensitized (S), and S treated with dexamethasone and carvacrol during a sensitization period were examined. Th2 and Th17 population as well as the gene expression of IL-4, IL-17, and TGF-β were increased, but Th1, Th1/Th2 ratio, the gene expression of IFN-γ and FOXP3 as well as the IFN-γ/IL-4 ratio were decreased in S compared with control group ( P < 0.001 for all cases). Carvacrol treatment caused significant reduction of Th2 and Th17 population as well as gene expression of IL-4, IL-17, and TGF-β but increase in Treg cells, Th1/Th2 ratio, gene expressions of FOXP3, IFN-γ, and IFN-γ/IL-4 ratio ( P < 0.05 to P < 0.001). The population of Th1, Th2, Th17 cells as well as the gene expression of IL-4, IL-17, and TGF-β were significantly decreased, but only Treg was increased in the dexamethasone treatment group ( P < 0.05 to P < 0.001). Carvacrol treatment during the sensitization period showed a more specific effect on Th1/Th2 imbalance in sensitized mice than dexamethasone, which may indicate the therapeutic potentials of carvacrol in disorders associated with Th1/Th2 imbalance such as asthma.