Assessment of the Antioxidant Activity of Catechin in Nutraceuticals: Comparison between a Newly Developed Electrochemical Method and Spectrophotometric Methods

The analysis of antioxidants in different foodstuffs has become an active area of research, which has led to many recently developed antioxidant assays. Many antioxidants exhibit inherent electroactivity, and, therefore, the use of electrochemical methods could be a viable approach for evaluating the overall antioxidant activity of a matrix of nutraceuticals without the need for adding reactive species. Green tea is believed to be a healthy beverage due to a number of therapeutic benefits. Catechin, one of its constituents, is an important antioxidant and possesses free radical scavenging abilities. The present paper describes the electrochemical properties of three screen-printed electrodes (SPEs), the first one based on carbon nanotubes (CNTs), the second one based on gold nanoparticles (GNPs) and the third one based on carbon nanotubes and gold nanoparticles (CNTs-GNPs). All three electrodes were modified with the laccase (Lac) enzyme, using glutaraldehyde as a cross-linking agent between the amino groups on the laccase and aldehyde groups of the reticulation agent. As this enzyme is a thermostable catalyst, the performance of the biosensors has been greatly improved. Electro-oxidative properties of catechin were investigated using cyclic voltammetry (CV) and differential pulse voltammetry (DPV), and these demonstrated that the association of CNTs with GNPs significantly improved the sensitivity and selectivity of the biosensor. The corresponding limit of detection (LOD) was estimated to be 5.6 × 10⁻⁸ M catechin at the CNT-Lac/SPE, 1.3 × 10⁻⁷ M at the GNP-Lac/SPE and 4.9 × 10⁻⁸ M at the CNT-GNP-Lac/SPE. The biosensors were subjected to nutraceutical formulations containing green tea in order to study their catechin content, using CNT-GNP-Lac/SPE, through DPV. Using a paired t-test, the catechin content estimated was in agreement with the manufacturer’s specification. In addition, the relationship between the CNT-GNP-Lac/SPE response at a specific potential and the antioxidant activity of nutraceuticals, as determined by conventional spectrophotometric methods (DPPH, galvinoxyl and ABTS), is discussed in the context of developing a fast biosensor for the relative antioxidant activity quantification.     

Molecular Mapping of Antifungal Mechanisms Accessing Biomaterials and New Agents to Target Oral Candidiasis

Oral candidiasis has a high rate of development, especially in immunocompromised patients. Immunosuppressive and cytotoxic therapies in hospitalized HIV and cancer patients are known to induce the poor management of adverse reactions, where local and systemic candidiasis become highly resistant to conventional antifungal therapy. The development of oral candidiasis is triggered by several mechanisms that determine oral epithelium imbalances, resulting in poor local defense and a delayed immune system response. As a result, pathogenic fungi colonies disseminate and form resistant biofilms, promoting serious challenges in initiating a proper therapeutic protocol. Hence, this study of the literature aimed to discuss possibilities and new trends through antifungal therapy for buccal drug administration. A large number of studies explored the antifungal activity of new agents or synergic components that may enhance the effect of classic drugs. It was of significant interest to find connections between smart biomaterials and their activity, to find molecular responses and mechanisms that can conquer the multidrug resistance of fungi strains, and to transpose them into a molecular map. Overall, attention is focused on the nanocolloids domain, nanoparticles, nanocomposite synthesis, and the design of polymeric platforms to satisfy sustained antifungal activity and high biocompatibility with the oral mucosa.     

Relationship of working alliance to mutual and unilateral termination.

Examined the relationship between strength of working alliance after the 3rd session and unilateral client termination. Participants were 4 PhD psychologists and 6 practicum trainees and their 103 college student clients. Both members of 91 counseling dyads (88%) completed the short version of the Working Alliance Inventory (T. J. Tracey and A. M. Kokotovic, 1989) after the 3rd counseling session. Counselor ratings of working alliance were positively associated with mutual termination. Client working alliance ratings did not relate to termination type. It was suggested that counselors focus directly on strengthening weak alliances with clients to prevent client unilateral termination. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Doctoral students' beliefs about authorship credit for dissertations.

This study used 8 vignettes to investigate the beliefs of 326 doctoral students in school psychology concerning credit for authorship of an article based on the dissertation. The vignettes varied according to who originated the topic of the dissertation (student or advisor) and who wrote an article based on the dissertation and received credit for authorship on that article. Responses to the vignettes indicated that respondents believed it is more desirable and ethical for a dissertation design to be that of the student rather than of the advisor. Respondents also believed that it is more desirable and ethical for the student to be either sole or first author of an article based on the dissertation, regardless of who (student or advisor) originated the topic. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Resveratrol Modulation of Apoptosis and Cell Cycle Response to Cisplatin in Head and Neck Cancer Cell Lines

In head and neck cancers, the effectiveness of cisplatin (CisPt) treatment is limited by its toxicity, especially when higher doses are necessary, and the possible occurrence of cisplatin resistance. This study evaluated the effects of resveratrol (RSV) on the expression of different genes involved in the response of human tumor cells (FaDu, PE/CA-PJ49) to cisplatin therapy. Our results revealed that RSV induced apoptosis amplification in both FaDu and PE/CA-PJ49 cells and modulated the expression of specific genes differently than in normal HaCaT cells. In FaDu cells, combined CisPt + RSV treatment induced an increase in apoptosis, which was associated with an increase in c-MYC and TP53 and a decrease in BCL-2 expression. While CisPt + RSV treatment induced apoptosis in PE/CA-PJ49 cells by inhibition of BCL-2 associated with high levels of MDM-2 and subsequently led to inhibition of TP53 gene expression. Decreased c-MYC expression in PE/CA-PJ49 treated with CisPt + RSV was accompanied by cell cycle blockage in G0/G1 phase. In conclusion, RSV influences tumor cell response to CisPt by inducing apoptosis and modulating gene expression. In addition, in normal HaCaT cells, RSV was able to reduce the harmful effects of CisPt.     

Devaluation of a degree.

Agrees with D. Shakow's (see record 1978-30686-001) article on clinical psychology 50 yrs later that clinical psychology is changing from a scientist-professional model to a professional-scientist or purely professional model. The author argues that without a supervised research experience, the professional-school graduate would be operating under a handicap, and few such students would choose to do research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Goal consensus and collaboration.

This article updates our previous article in this journal (Tryon & Winograd, 2001) by examining via meta-analyses results of recent studies, published from 2000 through 2009, that relate goal consensus and collaboration to treatment outcome. Specifically, 15 studies with a total sample size of 1,302 yielded a goal consensus-psychotherapy outcome effect size of .34 (SD = .19, p SD = .17, p     

Behavior of Dental/Implant Alloys in Commercial Mouthwash Solution Studied by Electrochemical Techniques

This study investigates the electrochemical behavior of the various dental materials: Paliag (Ag-Pd based), Wiron 99 (Ni-Cr based), Cp-Ti (commercial pure titanium), and experimental Ti12Mo5Ta alloy in commercial mouthwash solution with 500 ppm F^? (Oral B^®) and compares it with the behavior of the same dental materials in artificial saliva. Linear potentiodynamic polarization (LPP) and electrochemical impedance spectroscopy (EIS) are the electrochemical procedures of investigation. The passivation of all dental samples in artificial saliva and mouthwash solution occurred spontaneously at open circuit potential. The corrosion current density of all tested dental materials in mouthwash solution were low (1-2 μA/cm²). The results suggest a non-predominant fluoride effect on the passive layer formed on all samples at open circuit potential. No passivation could be established with Paliag alloy when polarized in mouthwash solution. The EIS results confirm that all dental sample exhibit passivity in mouthwash solution at open circuit potential (polarization resistance was around 5 × 10⁵ Ω cm²). For Paliag alloy after LPP in mouthwash solution the protectiveness passive layer was no more present. The corrosion resistances of four dental materials in mouthwash solution are in the following order: Ti12Mo5Ta > Cp-Ti > Wiron 99 > Paliag.     

Characterization of oils from Fazenda Belém – Potiguar Basin,Northeast Brazil

Asphaltenes (isolated by preparative TLC) from Potiguar Basin (Brazil) crude oils were submitted to mild oxidation to disrupt their structure, releasing the occluded oil. The released hydrocarbons were compared with those from the original crude oil, in order to provide an additional insight regarding composition in biomarkers and depositional paleoenvironment. It was possible to suggest that the oil samples present low thermal evolution, marine depositional environment and anoxide. The results showed that the release of these occluded hydrocarbon, which are remnants from the original oil, can be a tool for the geochemical study of highly biodegraded oils, leading to better maturation and origin information.