Influence of Light Intensity on Surface Free Energy and Dentin Bond Strength of Core Build-up Resins

Objective: We examined the influence of light intensity on surface free energy characteristics and dentin bond strength of dual-cure direct core build-up resin systems. Methods: Two commercially available dual-cure direct core build-up resin systems, Clearfil DC Core Automix with Clearfil Bond SE One and UniFil Core EM with Self-Etching Bond, were studied. Bovine mandibular incisors were mounted in acrylic resin and the facial dentin surfaces were wet ground on 600-grit silicon carbide paper. Adhesives were applied to dentin surfaces and cured with light intensities of 0 (no irradiation), 200, 400, and 600 mW/cm2. The surface free energy of the adhesives (five samples per group) was determined by measuring the contact angles of three test liquids placed on the cured adhesives. To determine the strength of the dentin bond, the core build-up resin pastes were condensed into the mold on the adhesive-treated dentin surfaces according to the methods described for the surface free energy measurement. The resin pastes were cured with the same light intensities as those used for the adhesives. Ten specimens per group were stored in water maintained at 37°C for 24 hours, after which they were shear tested at a crosshead speed of 1.0 mm/minute in a universal testing machine. Two-way analysis of variance (ANOVA) and a Tukey-Kramer test were performed, with the significance level set at 0.05. Results: The surface free energies of the adhesive-treated dentin surfaces decreased with an increase in the light intensity of the curing unit. Two-way ANOVA revealed that the type of core build-up system and the light intensity significantly influence the bond strength, although there was no significant interaction between the two factors. The highest bond strengths were achieved when the resin pastes were cured with the strongest light intensity for all the core build-up systems. When polymerized with a light intensity of 200 mW/cm2 or less, significantly lower bond strengths were observed. Conclusions: The data suggest that the dentin bond strength of core build-up systems are still affected by the light intensity of the curing unit, which is based on the surface free energy of the adhesives. On the basis of the results and limitations of the test conditions used in this study, it appears that a light intensity of >400 mW/cm2 may be required for achieving the optimal dentin bond strength

Impurity-induced magnetic order in the mixture of two spin gap systems (CH3)2CHNH3CuCl3 and (CH3)2CHNH3CuBr3

The ground state of the solid solution of the two spin gap systems (CH3)2CHNH3CuCl3 and (CH3)2CHNH3CuBr3 has been investigated by 1H-NMR. The existence of a magnetic ordering in the sample with the Cl-content x=0.85 was clearly demonstrated by a drastic splitting in a resonance line at low temperatures below TN=13.5K. The observed NMR spectra in the ordered state was qualitatively consistent with the simple antiferromagnetic state.Comment: QuBS200

Direct conversion of carlactonoic acid to orobanchol by cytochrome P450 CYP722C in strigolactone biosynthesis

Strigolactones (SLs) are carotenoid-derived phytohormones and rhizosphere signaling molecules for arbuscular mycorrhizal fungi and root parasitic weeds. Why and how plants produce diverse SLs are unknown. Here, cytochrome P450 CYP722C is identified as a key enzyme that catalyzes the reaction of BC-ring closure leading to orobanchol, the most prevalent canonical SL. The direct conversion of carlactonoic acid to orobanchol without passing through 4-deoxyorobanchol is catalyzed by the recombinant enzyme. By knocking out the gene in tomato plants, orobanchol was undetectable in the root exudates, whereas the architecture of the knockout and wild-type plants was comparable. These findings add to our understanding of the function of the diverse SLs in plants and suggest the potential of these compounds to generate crops with greater resistance to infection by noxious root parasitic weeds

Genome editing in the mushroom-forming basidiomycete Coprinopsis cinerea, optimized by a high-throughput transformation system

Mushroom-forming basidiomycetes produce a wide range of metabolites and have great value not only as food but also as an important global natural resource. Here, we demonstrate CRISPR/Cas9-based genome editing in the model species Coprinopsis cinerea. Using a high-throughput reporter assay with cryopreserved protoplasts, we identified a novel promoter, CcDED1pro, with seven times stronger activity in this assay than the conventional promoter GPD2. To develop highly efficient genome editing using CRISPR/Cas9 in C. cinerea, we used the CcDED1pro to express Cas9 and a U6-snRNA promoter from C. cinerea to express gRNA. Finally, CRISPR/Cas9-mediated GFP mutagenesis was performed in a stable GFP expression line. Individual genome-edited lines were isolated, and loss of GFP function was detected in hyphae and fruiting body primordia. This novel method of high-throughput CRISPR/Cas9-based genome editing using cryopreserved protoplasts should be a powerful tool in the study of edible mushrooms

Prospective Study of Gefitinib Readministration After Chemotherapy in Patients With Advanced Non-Small-Cell Lung Cancer Who Previously Responded to Gefitinib

The present study was designed to prospectively evaluate the clinical efficacy of gefitinib readministration in patients with advanced non-small cell lung cancer who responded well to initial gefitinib, followed by cytotoxic chemotherapy. Twenty subjects were enrolled, and 3 and 6 patients achieved partial response and stable disease, respectively. These findings provide valuable information for the management of previous gefitinib responders. Introduction: Salvage treatment for acquired resistance to epidermal growth factor receptor tyrosine kinase inhibitor in patients with non-small-cell lung cancer is a matter of clinical concern. Several retrospective reports have indicated the usefulness of epidermal growth factor receptor tyrosine kinase inhibitor readministration; however, there have been few prospective studies. Materials and Methods: This study was designed to prospectively evaluate the clinical efficacy of gefitinib readministration in patients with advanced or metastatic non-small-cell lung cancer who responded well to initial gefitinib treatment. The subjects received at least 1 regimen of cytotoxic chemotherapy after progressive disease with the initial gefitinib therapy. Gefitinib administration (250 mg/d, orally) was started after progressive disease with the previous chemotherapeutic regimen. The primary endpoint in the present study was the response rate. Results: Twenty patients were enrolled between April 2007 and May 2011. Three patients achieved partial response, and 6 showed stable disease. Thus, the overall response rate and disease control rate of gefitinib readministration were 15% (95% Cl, 3.21-37.9) and 45% (95% Cl, 23.1-68.5), respectively. Median progression-free survival and overall survival from the start of gefitinib readministration were 2.0 months (95% Cl, 0.9-3.1 months) and 12.0 months (95% Cl, 8.0-16.0 months), respectively. Conclusion: These results suggest that gefitinib readministration may be an option, albeit with a low response rate and short progression-free survival, for patients who responded well to initial gefitinib followed by systemic chemotherapy. These findings provide valuable information for the management of previous gefitinib responders.ArticleCLINICAL LUNG CANCER. 13(6):458-463 (2012)journal articl