A snapshot on prokaryotic diversity of the Solimões River basin (Amazon, Brazil).

The Amazon region has the largest hydrographic basin on the planet and is well known for its huge biodiversity of plants and animals. However, there is a lack of studies on aquatic microbial biodiversity in the Solimões River, one of its main water courses. To investigate the microbial biodiversity of this region, we performed 16S rRNA gene clone libraries from Solimões River and adjacent rivers and lakes. Our question was which microorganisms inhabit the different types of aquatic environments in this part of the basin, and how diversity varies among these environments (rivers and lakes). The microbial diversity generating 13 clone libraries of the bacterial 16S rRNA gene and 5 libraries of the archaeal 16S rRNA gene was assessed. Diversity measured by several alpha diversity indices (ACE, Chao, Shannon and Simpson) revealed significant differences in diversity indices between lake and river samples. The site with higher microbial diversity was in the Solimões River (4S), downstream the confluence with Purus River. The most common bacterial taxon was the cosmopolitan Polynucleobacter genus, widely observed in all samples. The phylum Thaumarchaeota was the prevailing archaeal taxon. Our results provide the first insight into the microbial diversity of the world's largest river basin.

A double-blind randomised clinical trial of two techniques for gingival displacement.

Knowledge about security and the potential damage originated by the gingival displacement techniques has not been described through randomised clinical studies. This crossover, double-blind, randomised clinical trial evaluated clinical and immunological factors related to conventional and cordless gingival displacement (GD) techniques, and patients' perceptions in 12 subjects with the employment of 2 GD techniques: conventional (gingival cord + 25% AlCl3 astringent gel) and cordless (15% AlCl3 astringent-based paste). In each subject, two anterior teeth were treated and a 10-day wash-out period separated the two treatments. Periodontal indices were evaluated before (baseline) and 1 and 10 days after GD. Interleukin 1ß, interleukin 6 and tumour necrosis factor α concentrations in gingival crevicular fluid were measured before and 1 day after GD. Subjective parameters (pain, unpleasant taste and stress) were also evaluated. Data were analysed by one-way repeated-measures analysis of variance and Tukey's test (immunological factors), the Friedman test (periodontal parameters) and Fisher's exact or chi-squared test (subjective parameters), with a significance level of 95%. Gingival bleeding index, probing depth and plaque index values did not differ significantly between groups at any timepoint. Neither technique resulted in worse periodontal indices. Both techniques yielded similar results for pain and unpleasant taste, but conventional GD was significantly more stressful than cordless GD for volunteers. Both treatments significantly increased mean concentrations of the three cytokines, with the conventional technique producing the highest cytokine levels. Cordless GD is less stressful for patients and results in lower post-treatment levels of inflammatory cytokines compared with conventional GD.

Crescimento, produção de fitomassa e teor de óleo essencial de folhas de capim citronela (Cymbopogon nardus (L. ) Rendle) em cultivo consorciado com algodoeiro colorido no semiárido mineiro / Growth, phytomass yield and essential oil content of leaves of citronella grass [Cymbopogon nardus (L. ) Rendle] intercropping with colored cotton

Avaliou-se o crescimento, a produção e o teor do óleo essencial de dois cortes de capim citronela em cultivo consorciado com algodoeiro colorido no semiárido. Para isso foram utilizados dois sistemas de consórcios (tratamentos): algodão colorido consorciado com capim citronela 3x1 e algodão colorido consorciado com capim citronela 1x1. A variedade de algodão colorido utilizada foi a BRS Rubi e as mudas de capim citronela foram produzidas no Horto de Plantas Medicinais da Unimontes. O delineamento experimental utilizado foi em blocos casualizados com dois tratamentos e 16 repetições. O experimento foi mantido em regime de sequeiro e foi avaliado a altura das plantas de capim citronela. Foram realizadas duas colheitas das folhas de capim citronela, sendo a primeira no momento da colheita da fibra do algodão e a segunda na rebrota do capim, seis meses após. Todas as plantas da parcela foram colhidas e as folhas frescas foram pesadas, no campo, com o auxílio de balança digital. Amostras das folhas colhidas foram retiradas e levadas para secagem em estufa com circulação forçada de ar a 35ºC até atingirem massa constante. Foi verificada a massa seca e posteriormente realizada a extração do óleo essencial pelo método de hidrodestilação em aparelho modificado de Clevenger. Os dados foram submetidos à análise de variância e as médias comparadas pelo teste Skott-Knott (p<0,05). A altura das plantas não diferiu entre os tratamentos nas colheitas. Para a produção de massa fresca e seca houve diferença entre os tratamentos apenas na segunda colheita. Neste caso, as plantas cultivadas em consórcio 1x1 produziram mais do que as do consórcio 3x1. O teor de óleo essencial de capim citronela não variou entre os dois sistemas de consórcio, tanto no primeiro como no segundo corte.

The research was performed to evaluate the growth, production and essential oil content of the two harvests of citronella grass in intercropped with colored cotton in semiarid.For this, was used two system consortium (treatments): colored cotton intercropped with citronella grass 3X1 and colored cotton intercropped with citronella grass 1X1. The variety of colored cotton used was BRS Rubi and the citronella grass seedlings were produced in the Medicinal Plants Garden of Unimontes. The experimental design used was randomized blocks with two treatments and 16 repetitions. The experiment was maintained under rainfed conditions. Was evaluated plant height of citronella grass. Citronella grass leaves were harvested twice: the first was made at harvest of cotton fiber and the second in the grass regrowth, six months later. All plants in the plot were harvested and the fresh leaves were weighed, in the field, with the aid of a digital balance. Samples from leaves harvested were collected and taken for drying in an oven with forced air at 35ºC until reaching constant weight. Dry mass was verified and the performed the extraction of essential oil by hydrodestilation in Clevenger modified apparatus. Data were subjected to analysis of variance and means compared by Skott-Knott test (p<0.05). The plants height did not differ between treatments in harvests. For the production of fresh and dry mass was significant difference between treatments only in the second harvest. In this case the plants cultivated in the consortium 1x1 produced more than in the consortium 3x1. The essential oil content of citronella grass did not vary between the two systems consortium, in the first and the second harvest.

Biaxial flexural strength of CAD/CAM ceramics.

AIM: Aim of the study was to evaluate the biaxial flexural strength of ceramics processed using the Cerec inLab system. The hypothesis was that the flexural strength would be influenced by the type of ceramic. METHODS: Ten samples (ISO 6872) of each ceramic (N.=50/n.=10) were made using Cerec inLab (software Cerec 3D) (Ø:15 mm, thickness: 1.2 mm). Three silica-based ceramics (Vita Mark II [VM], ProCad [PC] and e-max CAD ECAD]) and two yttria-stabilized tetragonal-zirconia-polycrystalline ceramics (Y-TZP) (e-max ZirCad [ZrCAD] and Vita In-Ceram 2000 YZ Cubes [VYZ]) were tested. The samples were finished with wet silicone carbide papers up to 1 200-grit and polished in a polishing machine with diamond paste (3 µm). The samples were then submitted to biaxial flexural strength testing in a universal testing machine (EMIC), 1 mm/min. The data (MPa) were analyzed using the Kruskal-Wallis and Dunn (5%) tests. Scanning electronic microscopy (SEM) was performed on a representative sample from each group. RESULTS: The values (median, mean±sd) obtained for the experimental groups were: VM (101.7, 102.1±13.65 MPa), PC (165.2, 160±34.7 MPa), ECAD (437.2, 416.1±50.1 MPa), ZrCAD (804.2, 800.8±64.47 MPa) and VYZ (792.7, 807±100.7 MPa). The type of ceramic influenced the flexural strength values (P=0.0001). The ceramics ECADa, e-max ZrCADa and VYZa presented similar flexural strength values which were significantly higher than the other groups (PCb and VM IIb), which were similar statistically between them (Dunn's test). The hypothesis was accepted. CONCLUSION: The polycrystalline ceramics (Y-TZP) should be material chosen for make FPDs because of their higher flexural strength values.