Efficacy of chemical and photoactivated disinfectants against Candida Albicans and assessment of hardness, roughness, and mass loss of acrylic denture base resin.

AIM: The present study aimed to assess the antimicrobial efficacy of hematoporphyrin derivative, sodium hypochlorite (NaOCl), glutaraldehyde (GaH), and a chlorhexidine (CHX) on mass loss (ML), microhardness, and surface roughness (Ra) of acrylic denture base colonized with C. Albicans. MATERIAL AND METHODS: A total of 40 heat cure acrylic resin dentures were fabricated and inoculated by the American Type Culture Collection (ATCC) of C. Albicans in an in-vitro situation. Specimens were divided into four groups (n = 10) based on the method of disinfection. Hematoporphyrin derivatives, 1% NaOCl, 2% GaH, and 4% CHX.The pre and post candida (CFU/ml) counts were recorded before and after immersion. ML, microhardness, and Ra of acrylic denture were also assessed. Statistical analysis was executed for CFU/mL (log10) for exposed C. Albicans by two-way ANOVA and Tukey's multiple tests (p > 0.05). For normality of the data, Dunnet's Simultaneous test was performed. RESULTS: In terms of candida strain analysis, pretreatment to posttreatment comparisons revealed a reduction in mean Candida count in all groups (p < 0.05). The highest ML value after post candida disinfection of acrylic denture was observed in 2% GaH (1.587 ± 0.25) treated specimens. The least microhardness value was found in group 1 when treated with hematoporphyrin (0.97 ± 0.22 VHN) which was significantly different from other groups (p < 0.05). Group 1 surface treated with hematoporphyrin derivate (1.84 ± 0.22 µm) showed the highest Ra values (p < 0.05). CONCLUSION: Acrylic denture base resin colonized with C. Albicans when treated with a chemical disinfectant of 4% chlorhexidine displayed the highest antimicrobial efficacy with reduced mass loss, less surface roughness, and maximum denture hardness.

Bond assessment of resin modified glass ionomer cement to dentin conditioned with photosensitizers, laser and conventional regimes.

AIM: To assess different conditioning regimes on shear bond strength (SBS) of resin modified glass ionomer cement (RMGIC) bonded to dentin MATERIAL AND METHODS: Fifty non carious intact maxillary molars were cleaned, isolated and randomly divided into five groups (n = 10). Before randomization, dentin surface was exposed and finished. Samples in group 1 were conditioned with methylene blue photosensitizer (MBP) 50 mg/l and activated by photodynamic therapy (PDT), Group 2: surface treated with Er,Cr:YSGG (ECL), Group 3: surface conditioned with polyacrylic acid (PAA) (control), Group 4: surface conditioned with 17 % Ethylenediaminetetraacetic acid (EDTA), Group 5: surface conditioned with total etch (Optibond solo Plus). For SBS testing the samples were placed in universal testing machine. Fracture analysis of debonded surfaces were evaluated using stereomicroscope at 40x magnification. Means and standard deviations were calculated using analysis of variance (ANOVA) and Tukey's post hoc test at a significance level of (p < 0.05). RESULTS: The maximum bond strength was found in group 5 conditioned with Optibond solo plus total etch (23.15 ±â€¯3.21 MPa). Whereas, the lowest bond values were observed in group 1 treated with MBP (15.25 ±â€¯1.54 MPa). Moreover, samples in group 2, group 3 and group 4 resulted in comparable bond strength (p > 0.05). CONCLUSION: MBP at 50 mg/l is not recommended to condition dentin prior to RMGIC application. Moreover, ECL has a potential to be suggested for dentin conditioning compared to PAA.

Evaluation of several flocculants for flocculating microalgae.

Flocculation of microalgae with chitosan, polyacrylamide, Al2(SO4)3, NaOH and HNO3 was evaluated. Their flocculation efficiencies and optimal dosages were discussed. The effects of the flocculants on cells viability were also investigated and the cells were found to be intact during the flocculation process. Moreover, the effects of flocculants on the extractions were evaluated. Lipid content after flocculants treatments showed no significant differences. Carbohydrate content was lower but protein content was higher after NaOH treatment than those after other treatments. Furthermore, the five flocculated media maintained approximate growth yields to that of the fresh medium in microalgal cultivation, indicating the five flocculated media could be recycled, thereby reducing the cost of biodiesel production from microalgae. Finally, economic comparison of the flocculants was made and the cost of using HNO3, including flocculating cells and recycling medium, was found to be the lowest.

A papain-induced disc degeneration model for the assessment of thermo-reversible hydrogel-cells therapeutic approach.

Nucleus pulposus (NP) regeneration by the application of injectable cell-embedded hydrogels is an appealing approach for tissue engineering. We investigated a thermo-reversible hydrogel (TR-HG), based on a modified polysaccharide with a thermo-reversible polyamide [poly(N-isopropylacrylamide), pNIPAM], which is made to behave as a liquid at room temperature and hardens at > 32 °C. In order to test the hydrogel, a papain-induced bovine caudal disc degeneration model (PDDM), creating a cavity in the NP, was employed. Human mesenchymal stem cells (hMSCs) or autologous bovine NP cells (bNPCs) were seeded in TR-HG; hMSCs were additionally preconditioned with rhGDF-5 for 7 days. Then, TR-HG was reversed to a fluid and the cell suspension injected into the PDDM and kept under static loading for 7 days. Experimental design was: (D1) fresh disc control + PBS injection; (D2) PDDM + PBS injection; (D3) PDDM + TR-HG (material control); (D4) PDDM + TR-HG + bNPCs; (D5) PDDM + TR-HG + hMSCs. Magnetic resonance imaging performed before and after loading, on days 9 and 16, allowed imaging of the hydrogel-filled PDDM and assessment of disc height and volume changes. In gel-injected discs the NP region showed a major drop in volume and disc height during culture under static load. The RT-PCR results of injected hMSCs showed significant upregulation of ACAN, COL2A1, VCAN and SOX9 during culture in the disc cavity, whereas the gene expression profile of NP cells remained unchanged. The cell viability of injected cells (NPCs or hMSCs) was maintained at over 86% in 3D culture and dropped to ~72% after organ culture. Our results underline the need for load-bearing hydrogels that are also cyto-compatible.

[Comparative stability assessment of laccases from the basidiomycetes Coriolus hirsutus and Coriolus zonatus in the presence of effectors]. / Sravnitel'noe izuchenie stabil'nosti lakkaz iz bazidiomitsetov Coriolus hirsutus i Coriolus zonatus v prisutstvii éffectorov.

Stability characteristics of the laccases of the basidiomycetes Coriolus hirsutus and Coriolus zonatus were measured comparatively at temperatures 25 and 40 degrees C in the presence of various effectors (proteins, salts, polyalcohols, polyacids, and polyelectrolytes). Stabilization effects of cations on the laccases from C. hirsutus and C. zonatus decreased in the descending series Cu2+ > Mg2+ > Ca2+ and Ca2+ > Mg2+ > Mn2+, respectively. Tween 20 caused insignificant stabilization of the two enzymes. The C. zonatus laccase was also insignificantly stabilized as a result of treatment with bovine serum albumin. The enzymatic activity of the laccase preparations from C. hirsutus and C. zonatus was conserved virtually completely after vacuum drying (84 and 93%, respectively). The most effective stabilizer of the C. hirsutus laccase was found to be dextran (17 kD). Dry preparations treated with this agent conserved up to 95% of the enzymatic activity. The most effective stabilizer of the C. zonatus was polyacrylic acid (102% of the initial activity).

Avaliação da reação tecidual de uma resina termoplástica em tecido subcutâneo de ratos / Assessment of subcutaneous rat tissue reaction to a thermoplastic resin

A reação tecidual da resina tesmoplástica TAK Hydroplastic foi avaliada por meio da sua implantação em tecido subcutâneo de ratos nos períodos de observação de duas, três, seis e 12 semanas. A resina acrílica incolor termicamente ativada foi escolhida como Grupo Controle. No final de duas semanas o tecido subcutâneo dos ratos adjacentes aos corpos de prova do Grupo Controle e Experimental, exibiram uma reação inflamatória moderada que decresceu para leve no período de observação de 12 semanas, mostrando ser o TAK Hydroplastic, um material aceitável em testes de implantação subcutânea