Contribution of the cashew gum (Anacardium occidentale L.) for development of layer-by-layer films with potential application in nanobiomedical devices

The search for bioactive molecules to be employed as recognition elements in biosensors has stimulated researchers to pore over the rich Brazilian biodiversity. In this sense, we introduce the use of natural cashew gum (Anacardium occidentale L) as an active biomaterial to be used in the form of layer-by-layer films, in conjunction with phthalocyanines, which were tested as electrochemical sensors for dopamine detection. We investigated the effects of chemical composition of cashew gum from two different regions of Brazil (Piaui and Ceara states) on the physico-chemical characteristics of these nanostructures. The morphology of the nanostructures containing cashew gum was studied by atomic force microscopy which indicates that smooth films punctuated by globular features were formed that showed low roughness values. The results indicate that, independent of the origin, cashew gum stands out as an excellent film forming material with potential application in nanobiomedical devices as electrochemical sensors. (c) 2012 Elsevier B.V. All rights reserved.

Spray drying microencapsulation of Lippia sidoides extracts in carbohydrate blends

The microencapsulation of Lippia sidoides extracts in blends of carbohydrates was investigated. The extraction conditions were determined through a 2(2) factorial design. The effects of the plant:solvent ratio (A - 7.5:100 and 15:100 m/m) and the extraction time (B - 30 and 90 min) on thymol content of extractive solutions were evaluated, using a 2:1 (v/v) of ethanol:water at a temperature of 50 degrees C, as a solvent system. The selected extract was subjected to spray drying. Blends of maltodextrin and gum arabic at different proportions (4:1; 3:2; 2:3; 0:1) (m/m) were used as encapsulating material. The protective effects of the maltodextrin and gum arabic blends were evaluated by determination of the thymol retention in the dried product, which ranged from 70.2 to 84.2% (related to the content in the extractive solution). An increase in the gum arabic to maltodextrin (DE10) ratio has positive effect on thymol retention. L. sidoides extracts and spray-dried products showed antifungal activity against tested fungal strains (Candida albicans - ATCC 64548, Candida glabrata - ATCC 90030, Candida krusei - ATCC 6258, and Candida parapsilosis - ATCC 22019), evidencing their potential as a natural antifungal agent for medicinal, food, and cosmeceutical purposes. (C) 2012 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Microbiota benefits after inulin and partially hydrolized guar gum supplementation - a randomized clinical trial in constipated women

Introduction: Prebiotics positively affect gut microbiota composition, thus improving gut function. These properties may be useful for the treatment of constipation. Objectives: This study assessed the tolerance and effectiveness of a prebiotic inulin/partially hydrolyzed guar gum mixture (I-PHGG) for the treatment of constipation in females, as well as its influence on the composition of intestinal microbiota and production of short chain fatty acids. Methods: Our study enrolled 60 constipated female health worker volunteers. Participants reported less than 3 bowel movements per week. Volunteers were randomized to treatment with prebiotic or placebo. Treatment consisted of 3 weeks supplementation with 15 g/d I-PHGG (fiber group) or maltodextrin (placebo group). Abdominal discomfort, flatulence, stool consistency, and bowel movements were evaluated by a recorded daily questionnaire and a weekly interview. Changes in fecal bacterial population and short chain fatty acids were assessed by real-time PCR and gas chromatography, respectively. Results: There was an increased frequency of weekly bowel movements and patient satisfaction in both the fiber and placebo groups with no significant differences. Total Clostridium sp significantly decreased in the fiber group (p = 0.046) and increased in the placebo group (p = 0.047). There were no changes in fecal short chain fatty acid profile. Conclusions: Consumption of I-PHGG produced clinical results comparable to placebo in constipated females, but had additional protective effects on gut rnicrobiota by decreasing the amount of pathological bacteria of the Clostridium genera.

Gellan Gum-LiI Gel Polymer Electrolytes

Gellan-based polymer electrolytes (PEs), doped with lithium iodide (LiI), were prepared and their electrical properties were characterized. The samples are thermally stable up to 234 degrees C and exhibit ionic conductivity of 3.8 x 10(-4) S/cm at room temperature for the sample doped with 40 wt% of LiI. Addition of 10 wt% of glycerol promotes an increase of the ionic conductivity to 1.5 x 10(-3) S/cm, which remains stable up to 100 degrees C. The activation energies of 2.4 to 12.4 kJ/mol were derived from the Arrhenius model. The repeated ionic conductivity measurements as a function of temperature show that these membranes can be reversibly used between the room temperature and 100 degrees C.

In situ effect of chewing gum containing CPP–ACP on the mineral precipitation of eroded bovine enamel

Objectives: Stimulation of salivary flow is considered a preventive strategy for dental erosion. Alternatively, products containing calcium phosphate, such as a complex of casein phosphopeptide–amorphous calcium phosphate (CPP–ACP), have also been tested against dental erosion. Therefore, this in situ study analyzed the effect of chewing gum containing CPP–ACP on the mineral precipitation of initial bovine enamel erosion lesions. Methods: Twelve healthy adult subjects wore palatal appliances with two eroded bovine enamel samples. The erosion lesions were produced by immersion in 0.1% citric acid (pH 2.5) for 7 min. During three experimental crossover in situ phases (1 day each), the subjects chewed a type of gum, 3 times for 30 min, in each phase: with CPP–ACP (trident total), without CPP–ACP (trident), and no chewing gum (control). The Knoop surface microhardness was measured at baseline, after erosion in vitro and the mineral precipitation in situ. The differences in the degree of mineral precipitation were analyzed using repeated measures (RM-) ANOVA and post hoc Tukey’s test ( p < 0.05). Results: Significant differences were found among the remineralizing treatments ( p < 0.0001). Chewing gum (19% of microhardness recovery) improved the mineral precipitation compared to control (10%) and the addition of CPP–ACP into the gum promoted the best mineral precipitation effect (30%). Conclusions: Under this protocol, CPP–ACP chewing gum improved the mineral precipitation of eroded enamel. Clinical significance: Since the prevalence of dental erosion is steadily increasing, CPP–ACP chewing gum might be an important strategy to reduce th eprogression of initial erosion lesions.

Correlation of photodynamic activity and singlet oxygen quantum yields in two series of hydrophobic monocationic porphyrins

The photodynamic properties of eight hydrophobic monocationic methyl and ruthenium polypyridine complex derivatives of free-base and zinc(II) meso-triphenyl-monopyridylporphyrin series were evaluated and compared using HeLa cells as model. The cream-like polymeric nanocapsule formulations of marine atelocollagen/xanthan gum, prepared by the coacervation method, exhibited high phototoxicity but negligible cytotoxicity in the dark. Interestingly, the formulations of a given series presented similar photodynamic activities but the methylated free-base derivatives were significantly more phototoxic than the respective ruthenated photosensitizers, reflecting the higher photoinduced singlet oxygen quantum yields of those monocationic porphyrin dyes.

Effectiveness of Tooth Wipes in Removing Babies' Dental Biofilm

Purpose: To assess the effectiveness of tooth wipes in removing dental biofilm from babies' anterior teeth, as well as to evaluate the babies' behaviour and the guardians' preference concerning hygiene methods. Materials and Methods: In this random blind cross-over study, 50 high caries risk babies, from 8 to 15 months old, were divided into two groups: babies with oral hygiene performed by caregivers (n = 25) or by their mothers (n = 25). The caregivers and mothers removed biofilm using three methods of oral hygiene (tooth wipes, toothbrushes and gauze), one in each experimental phase. Professional cleaning was done before each phase, which had 2 days of biofilm accumulation and 1 experimental day, when caregivers and mothers used one method to remove biofilnn. Examiners blinded to the study design assessed the biofilm index at baseline, prior to and following biofilm removal using each method. The babies' behaviour and the mothers'/caregivers' preference were assessed. Results: The tooth wipes, toothbrushes and gauze significantly reduced the amount of biofilm (P < 0.001). The mothers' group removed more biofilm than the caregivers' group, using toothbrushes or tooth wipes (P < 0.05). Babies in the mothers' group had better behaviour using tooth wipes than toothbrushes (P < 0.05). Mothers and caregivers preferred to use tooth wipes. Conclusions: Tooth wipes are effective in removing biofilrn from babies' anterior teeth and are the method best accepted by mothers, caregivers and babies.

Xylitol concentrations in artificial saliva after application of different xylitol dental varnishes

Objective: The present study analyzed xylitol concentrations in artificial saliva over time after application of varnishes containing 10% and 20% xylitol. Material and Methods: Fifteen bovine enamel specimens (8x4 mm) were randomly allocated to 3 groups (n=5/group), according to the type of varnish used: 10% xylitol, 20% xylitol and no xylitol (control). After varnish application (4 mg), specimens were immersed in vials containing 500 mu L of artificial saliva. Saliva samples were collected in different times (1, 8, 12, 16, 24, 48 and 72 h) and xylitol concentrations were analyzed. Data were assessed by two-way repeated-measures ANOVA (p<0.05). Results: Colorimetric analysis was not able to detect xylitol in saliva samples of the control group. Salivary xylitol concentrations were significantly higher up to 8 h after application of the 20% xylitol varnish. Thereafter, the 10% xylitol varnish released larger amounts of that polyol in artificial saliva. Conclusions: Despite the results in short-term, sustained xylitol releases could be obtained when the 10% xylitol varnish was used. These varnishes seem to be viable alternatives to increase salivary xylitol levels, and therefore, should be clinically tested to confirm their effectiveness.

Cassava starch biodegradable films: Influence of glycerol and clay nanoparticles content on tensile and barrier properties and glass transition temperature

In this this study, glycerol content and its incorporation method on tensile and barrier properties of biodegradable films (BF) based on cassava starch were analyzed. ANOVA showed that the glycerol incorporation method did not influence the results (P > 0.05), however the glycerol content influenced significantly the tensile and barrier properties of the films (P < 0.05). Films prepared with lower glycerol content presented better tensile and barrier properties than films with higher content. Films were then prepared with addition of clay nanoparticles and their tensile and barrier properties and glass transition temperature were measured. ANOVA indicated that both glycerol and clay nanoparticles influenced significantly the tensile and barrier properties (P < 0.05), diminishing film permeability when clay nanoparticles were present, while the glass transition temperature was not influenced (P > 0.05). (C) 2011 Elsevier Ltd. All rights reserved.

Efeito de diferentes gomas de mascar sobre o pH salivar de crianças

Objective: To evaluate the effect of different chewing gum brands on the salivary pH of children with primary dentition. Method: Forty children were selected and assigned to four groups: control (no chewing gum); sugarless chewing gum; chewing gum with casein phosphopeptide-amorphous calcium phosphate; and chewing gum with xylitol. The first saliva collection was made after supervised tooth brushing for stabilization of the oral pH. Next, all children were instructed to drink slowly 100 mL of a cola-based soft drink (Coca-Cola®) and a new saliva collection was made 10 min later. Then, each group chewed on the chewing gum for 5 min and discarded it after this time. Saliva was collected again at 5, 10 and 15 min intervals after start using the chewing gum. Measurement of salivary pH was made with colorimetric test papers and a digital pH-meter. Data were analyzed statistically by analysis of variance and Tukey’s test at a 5% significance level. Results: The use of chewing gums accelerated the increase of salivary pH to considerably alkaline levels after consumption of an acidic beverage, especially within the first minutes. The highest levels were obtained in the groups of children that used chewing gums containing xylitol and casein phosphopeptide-amorphous calcium phosphate. Conclusion: Children that used the chewing gums after ingestion of an acidic soft drink presented an increase in salivary pH, with the best results in the groups that used chewing gums containing casein phosphopeptide-amorphous calcium phosphate and xylitol.

Metáteses árabes da metáfora: desvelar/velar

Um dos mais intrigantes fatos semânticos da língua árabe é a metátese, transposição de fonemas dentro de uma palavra, frequentemente com relação de sentido entre as formas metatéticas. Em m-th-l, a raiz triconsonantal para a palavra “metáfora”, as metáteses são imensamente sugestivas: Th-L-M and L- Th-M; a ambígua função da metáfora: mostrar e ocultar. A partir desse fato, o artigo discute esses aspectos da metáfora

Em direção ao máximo e além: Milton Nascimento e as tradições ocidental e árabe da virtude

Na tradição ocidental, a virtude tem sido sempre considerada a plenitude do ser humano, como resume Tomás de Aquino: ultimum potentiae, ou, em linguagem de hoje, o máximo do que se pode ser. Curiosamente essa mesma concepção ocorre em outras culturas, como a Tupi. Milton Nascimento compôs uma canção que expressa o próprio cerne dessa tradição. A língua árabe dá um passo além: a virtude excede!