Effect of pH variation on the subcritical crack growth parameters of glassy matrix ceramics

The goals of our study were to calculate the subcritical crack growth (SCG) parameters of two veneering ceramics stored in water or Streptococcus mutans (S. mutans) biofilm and remineralizing medium, with indentation flaws. Feldspar (VM7) and leucite‐reinforced (VM13) glass ceramic disks (Vita Zahnfabrik, Bad Säckingen, Germany) were made according to ISO 6872. Some specimens were indented with a Vickers diamond and the crack dimensions were measured. The specimens were fractured for a calculation of inert strength or further stored in water or submitted to pH variation, under preloading tension. Finally, the SCG parameters were calculated after the specimens were fractured under four stressing rates (MPa/s). Weibull analysis was conducted on non‐indented specimens. XPS was performed as qualitative analysis. The subcritical crack of leucite ceramic did not vary with the media storage, but the glass‐ceramic experienced a retarded growth after pH variation. The materials presented low Weibull modulus. Qualitative elemental analyses showed chemical modification on both ceramics. Therefore, the crack growth of leucite‐reinforced ceramic was less affected by the environment pH than glass‐ceramic

Nisina: um conservante natural para alimentos

O crescente interesse por alimentos processados e que ainda mantenham as suas características mais próximas do natural tem incentivado pesquisadores a buscar associações de tecnologias para conservar os alimentos com qualidade e segurança alimentar. Algumas bactérias ácido Táticas, como Lactococcus lactis NIOZRS, 6F3, NCFB894, ATCC11454, N8, NIZ022186, produzem as bacteriocinas ou peptideos antibacterianos, que retardam ou inibem o crescimento de outras bactérias. A bacteriocina nisina, que é naturalmente produzida em vários alimentos fermentados, vem sendo consumida por humanos há séculos. A nisina tem seu uso aprovado em alimentos em mais de 50 países, e, em 1988, o FDA concedeu-lhe o status de GRAS ("Generally Recognized As Safe"). Esta revisão mostra avanços nos estudos da bioquímica, genética, resistência e modo de ação, além da aplicabilidade desse peptídeo em alimentos. Estudos têm mostrado a baixa toxicidade da nisina e sua alta eficiência como conservante em alimentos. O uso da nisina em alimentos pode ser na forma de imersão do produto em uma solução que a contém ou ela pode ser incorporada nas embalagens ativas que, ao serem usadas no acondicionamento do produto será liberada de forma controlada para a sua superficie.The increasing interest processed foods that maintain its fresh characteristic has encouraged in producer to look for new technologies to preserve food with quality and microbiological safety. Some lactic acid bacteria, such as Lactococcus !octís NIOZRS, GP 3, NCFBS94, ATCCI 1454, N8, NIZOZZISG produce bacteriocins or antibacterial peptídes that kill or inhibit the growth of other bacteria. The peptide nisin is produced naturally in several fermented foods, and has been consumed by humans for centuries. It is approved for foodstuff use in more than 50 countries. In 1988, the FDA considered aísin with status of GRAS (”Generally Recognized as Safe"). This review outlines some advances in the studies of the biochemistry, genetics, resistance and mechanism of action besides the applicability of peptide as an additive in food. Research has show the low toxicity of nisina and its high efficiency as a food preservativo. Nisin can be Sprayed on the product surface or incorporated into the active packaging that will release it to the food surfac

The Importance of MDP Priming, Silica Blasting or Glazing on the Retention Force of Y-TZP Copings to Varying Geometry Tooth Abutments

To evaluate the influence of the convergence angle of tooth preparations and abutments height and several surface treatments for zirconia copings through the tensile retention test. 120 crown preparations were made in Nema G10 with the maxillary first molar anatomy. In total, 60 abutments of 5 mm height were divided into two groups of 6° and 20° convergence angles of tooth preparations, and 60 abutments with a convergence angle of tooth preparations of 12° were divided into groups of 4 and 6 mm heights. Three surface treatments used were MDP-primer (10-Methacryloyloxydecyl dihydrogen phosphate), glazing or silica blasting. The abutments were scanned to make zirconia copings (3Y-TZP–Yttria-Stabilized Tetragonal Zirconia Polycrystals, Vita In-Ceram YZ). After cementation, the mechanical cycling (2 × 106 cycles, 3 Hz, 100 N) was performed to aging. After cycling, the copings were tested in tensile (1 kN load cell; 0.5 mm/s speed). Both abutments support base and copings were embedded in acrylic resin with the aid of a device that maintained the long axis perpendicular to the horizontal plane. Data were analyzed with the two-way ANOVA and Tukey test (95%). ANOVA revealed that the convergence angle influenced the tensile retention (p = 0.0232), but the abutments height showed no statistically significant difference (p = 0.086). The MDP-primer and silica blasting showed higher retention forces in the specimens with height variations. For bonded zirconia crowns, the retention force provided by high convergence angle preparation is critical and cannot be improved by surface treatments. For short and long crown preparations, MDP-based Primers or Silica blasting are advisable to aid restoration longevity

Concepções de polivalência e professor polivalente: uma análise historico‐legal

As concepções de polivalência e professor polivalência são resultantes de um processo histórico relacionadas à visão de educação, escola, conhecimento e formação profissional. Assim, o texto descreve, a partir de alguns documentos oficiais educacionais, tal processo no período de 1970 até as reformas pós anos 1990. Percebe a noção de polivalência e professor polivalente associada a um sentido generalista e superficial de trato com os conteúdos curriculares denotando uma relação economicista de relação “custo‐benefício” sob a justificativa de se suprir o déficit de professores para atuarem na crescente população escolar com ensino obrigatório estendido no período militar. Após as reformas dos anos 90 os documentos dão indícios de uma lógica das competências tanto como conteúdo formativo profissional como modo de construção do conhecimento por parte dos sujeitos. Tais documentos referendam ainda uma noção de conhecimento baseada numa perspectiva de interdisciplinaridade um tanto frágil quando esta é transposta do contexto epistemológico para o contexto educacional e pedagógico o que fragiliza também, uma compreensão apolítica de competências aos processos de profissionalização docente reforçando uma lógica de responsabilização.

From blue light to clock genes in zebrafish ZEM-2S cells.

Melanopsin has been implicated in the mammalian photoentrainment by blue light. This photopigment, which maximally absorbs light at wavelengths between 470 and 480 nm depending on the species, is found in the retina of all classes of vertebrates so far studied. In mammals, melanopsin activation triggers a signaling pathway which resets the circadian clock in the suprachiasmatic nucleus (SCN). Unlike mammals, Drosophila melanogaster and Danio rerio do not rely only on their eyes to perceive light, in fact their whole body may be capable of detecting light and entraining their circadian clock. Melanopsin, teleost multiple tissue (tmt) opsin and others such as neuropsin and va-opsin, are found in the peripheral tissues of Danio rerio, however, there are limited data concerning the photopigment/s or the signaling pathway/s directly involved in light detection. Here, we demonstrate that melanopsin is a strong candidate to mediate synchronization of zebrafish cells. The deduced amino acid sequence of melanopsin, although being a vertebrate opsin, is more similar to invertebrate than vertebrate photopigments, and melanopsin photostimulation triggers the phosphoinositide pathway through activation of a G(q/11)-type G protein. We stimulated cultured ZEM-2S cells with blue light at wavelengths consistent with melanopsin maximal absorption, and evaluated the time course expression of per1b, cry1b, per2 and cry1a. Using quantitative PCR, we showed that blue light is capable of slightly modulating per1b and cry1b genes, and drastically increasing per2 and cry1a expression. Pharmacological assays indicated that per2 and cry1a responses to blue light are evoked through the activation of the phosphoinositide pathway, which crosstalks with nitric oxide (NO) and mitogen activated protein MAP kinase (MAPK) to activate the clock genes. Our results suggest that melanopsin may be important in mediating the photoresponse in Danio rerio ZEM-2S cells, and provide new insights about the modulation of clock genes in peripheral clocks

Effect of pH variation on the subcritical crack growth parameters of glassy matrix ceramics

The goals of our study were to calculate the subcritical crack growth (SCG) parameters of two veneering ceramics stored in water or Streptococcus mutans (S. mutans) biofilm and remineralizing medium, with indentation flaws. Feldspar (VM7) and leucite-reinforced (VM13) glass ceramic disks (Vita Zahnfabrik, Bad Säckingen, Germany) were made according to ISO 6872. Some specimens were indented with a Vickers diamond and the crack dimensions were measured. The specimens were fractured for a calculation of inert strength or further stored in water or submitted to pH variation, under preloading tension. Finally, the SCG parameters were calculated after the specimens were fractured under four stressing rates (MPa/s). Weibull analysis was conducted on non-indented specimens. XPS was performed as qualitative analysis. The subcritical crack of leucite ceramic did not vary with the media storage, but the glass-ceramic experienced a retarded growth after pH variation. The materials presented low Weibull modulus. Qualitative elemental analyses showed chemical modification on both ceramics. Therefore, the crack growth of leucite-reinforced ceramic was less affected by the environment pH than glass-ceramic

Quantitative PCR of <i>per1b</i>, <i>cry1b</i>, <i>per2</i> and <i>cry1a</i> in a <i>Danio rerio</i> embryonic cell line ZEM-2S.

<p>The cells (2×10∧6) were stimulated with blue light (450–475 nm, 87.85 to 95.17 µwatts/cm²) for 10 min, and total RNA was extracted 1, 2, 6 and 12 h after the stimulus. ‘a’ is significantly different from ‘b’ and ‘b’ is significantly different from ‘c’ (p<0.05). In this and in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0106252#pone-0106252-g002" target="_blank">figures 2</a> to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0106252#pone-0106252-g009" target="_blank">9</a>, values are the mean ± Standard Error of Mean (n = 4–9).</p

Quantitative PCR of <i>per2</i> and <i>cry1a</i> in a <i>Danio rerio</i> embryonic cell line ZEM-2S.

<p>The cells (2×10∧6) were stimulated with blue light (450–475 nm, 87.85 to 95.17 µwatts/cm²) for 10 min, in the presence or absence of the MEK inhibitor, PD-98059 at 40 µM, and total RNA was extracted 2 h after the stimulus.</p

Antinociceptive Activity of Borreria verticillata: In vivo and In silico Studies

Borreria verticillata (L.) G. Mey. known vassourinha has antibacterial, antimalarial, hepatoprotective, antioxidative, analgesic, and anti-inflammatory, however, its antinociceptive action requires further studies. Aim of the study evaluated the antinociceptive activity of B. verticillata hydroalcoholic extract (EHBv) and ethyl acetate fraction (FAc) by in vivo and in silico studies. In vivo assessment included the paw edema test, writhing test, formalin test and tail flick test. Wistar rats and Swiss mice were divided into 6 groups and given the following treatments oral: 0.9% NaCl control group (CTRL), 10 mg/kg memantine (MEM), 10 mg/kg indomethacin (INDO), 500 mg/kg EHBv (EHBv 500), 25 mg/kg FAc (FAc 25) and 50 mg/kg FAc (FAc 50). EHBv, FAc 25 and 50 treatments exhibited anti-edematous and peripheral antinociceptive effects. For in silico assessment, compounds identified in FAc were subjected to molecular docking with COX-2, GluN1a and GluN2B. Ursolic acid (UA) was the compound with best affinity parameters (binding energy and inhibition constant) for COX-2, GluN1a, GluN2B, and was selected for further analysis with molecular dynamics (MD) simulations. In MD simulations, UA exhibited highly frequent interactions with residues Arg120 and Glu524 in the COX-2 active site and NMDA, whereby it might prevent COX-2 and NMDA receptor activation. Treatment with UA 10 mg/Kg showed peripheral and central antinociceptive effect. The antinociceptive effect of B. verticillata might be predominantly attributed to peripheral actions, including the participation of anti-inflammatory components. Ursolic acid is the main active component and seems to be a promising source of COX-2 inhibitors and NMDA receptor antagonists

No one-size-fits-all solution to clean GBIF.

Species occurrence records provide the basis for many biodiversity studies. They derive from georeferenced specimens deposited in natural history collections and visual observations, such as those obtained through various mobile applications. Given the rapid increase in availability of such data, the control of quality and accuracy constitutes a particular concern. Automatic filtering is a scalable and reproducible means to identify potentially problematic records and tailor datasets from public databases such as the Global Biodiversity Information Facility (GBIF; http://www.gbif.org), for biodiversity analyses. However, it is unclear how much data may be lost by filtering, whether the same filters should be applied across all taxonomic groups, and what the effect of filtering is on common downstream analyses. Here, we evaluate the effect of 13 recently proposed filters on the inference of species richness patterns and automated conservation assessments for 18 Neotropical taxa, including terrestrial and marine animals, fungi, and plants downloaded from GBIF. We find that a total of 44.3% of the records are potentially problematic, with large variation across taxonomic groups (25–90%). A small fraction of records was identified as erroneous in the strict sense (4.2%), and a much larger proportion as unfit for most downstream analyses (41.7%). Filters of duplicated information, collection year, and basis of record, as well as coordinates in urban areas, or for terrestrial taxa in the sea or marine taxa on land, have the greatest effect. Automated filtering can help in identifying problematic records, but requires customization of which tests and thresholds should be applied to the taxonomic group and geographic area under focus. Our results stress the importance of thorough recording and exploration of the meta-data associated with species records for biodiversity research