384 research outputs found
High Power Impulse Magnetron Sputtering of CIGS Thin Films for High Efficiency Thin Film Solar Cells
In this work CuIn1-xGaxSe2 (CIGS) thin films with three different values of x (0; 0.28; 1) were preparedby nonreactive sputtering of Cu, In and Ga in HiPIMS (High Power Impulse Magnetron Sputtering) orDC magnetron and subsequently selenized in an Ar+Se atmosphere. Optical emission spectroscopy(OES) was used to monitor some basic plasma parameters during sputtering of metallic precursors. CIGSthin film characteristics were measured using X-ray diffraction (XRD), scanning electron microscopy(SEM), Raman spectroscopy, energy-dispersive X-ray spectroscopy (EDX) and other techniques
Comparison of fusobacterium nucleatum and porphyromonas gingivalis lipopolysaccharides clinically isolated from root canal infection in the induction of pro-inflammatory cytokines secretion
The aim of this study was to compare the biological activity of lipopolysaccharides (LPS) purified from Fusobacterium nucleatum and Porphyromonas gingivalis strains, both isolated from primary endodontic infection (PEI) in the levels of IL-1ÎČ and TNF-α released by macrophage cells. Moreover, LPS was purified from F. nucleatum and P. gingivalis American Type Collection (ATCC) and its biological activity was compared to respectively clinical isolates strains. F. nucleatum and P. gingivalis strains clinically isolated from PEI had their identification confirmed by sequencing the 16S rRNA gene. LPS from F. nucleatum and P. gingivalis and their respective ATCC strains were extracted by using Tri-reagent method. Macrophages (Raw 264.7) were stimulated with LPS at 100 ng/mL for 4, 8 and 12 h. Secretion of IL-1 ÎČ and TNF-α was also determined. Paired t-test, repeated measures ANOVA and one-way ANOVA were employed. All LPS induced significant production of IL-1ÎČ and TNF-α, with the former being secreted at higher levels than the latter in all time-points. F. nucleatum induced a higher expression of both cytokines compared to P. gingivalis (p<0.05). No differences were observed between clinical and ATCC strains, as both presented the same potential to induce pro-inflammatory response. It was concluded that F. nucleatum and P. gingivalis LPS presented different patterns of activation against macrophages as seen by the IL-1ÎČ and TNF-α production, which may contribute to the immunopathogenesis of apical periodontitis. Moreover, clinical and ATCC strains grown under the same in vitro environment conditions presented similar biological activity272202207CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTĂFICO E TECNOLĂGICO - CNPQFUNDAĂĂO DE AMPARO Ă PESQUISA DO ESTADO DE SĂO PAULO - FAPESP302575/2009-0; 150557/2011-6; 308162/2014-510/19136-1; 10/17877- 4; 11/50051-5; 11/50510-0; 11/09047-4O objetivo deste estudo foi comparar a atividade biolĂłgica de lipopolissacarĂdeos (LPS) purificados a partir de linhagens de Fusobacterium nucleatum e Porphyromonas gingivalis, ambas isoladas de infecçÔes endodĂŽnticas primĂĄrias (IEP) nos nĂveis de IL-1ÎČ e TNF-α produzidos por macrĂłfagos. Adicionalmente, LPS foi purificado de F. nucleatum e P. gingivalis "American Type Collection" (ATCC) e sua atividade comparada Ă s respectivas linhagens clinicamente isoladas. Linhagens de F. nucleatum e P. gingivalis isoladas clinicamente de IEP tiveram sua identificação confirmada por sequenciamento do gene 16S rRNA. LPS de F. nucleatum e P. gingivalis e das respectivas linhagens foram extraĂdos com o uso do mĂ©todo "Tri-reagent". MacrĂłfagos (Raw 264.7) foram estimulados com LPS a 100 ng/mL por 4, 8 e 12 h. A secreção de IL-1ÎČ e de TNF-α foi determinada. Foram usados os testes t-pareado, ANOVA de medidas repetidas e ANOVA de um fator. Todos os LPS induziram a produção significante de IL-1ÎČ e TNF-α, sendo o primeiro secretado em mais altas concentraçÔes que o Ășltimo em todos os tempos avaliados. F. nucleatum induziu uma maior expressĂŁo de ambas as citocinas comparativamente ao P. gingivalis (p<0,05). NĂŁo foram observadas diferenças entre as linhagens clĂnica e ATCC, uma vez que ambas apresentaram o mesmo potencial de indução da resposta prĂł-inflamatĂłria. Conclui-se que F. nucleatum e P. gingivalis possuem diferentes padrĂ”es de ativação dos macrĂłfagos, como visto pela produção de IL-1ÎČ e TNF-α, o que pode contribuir para a imunopatogĂȘnese da periodontite apical. Ainda, linhagens clĂnica e ATCC mantidas no mesmo ambiente in vitro apresentaram ativação biolĂłgica semelhant
Global and regional brain metabolic scaling and its functional consequences
Background: Information processing in the brain requires large amounts of
metabolic energy, the spatial distribution of which is highly heterogeneous
reflecting complex activity patterns in the mammalian brain.
Results: Here, it is found based on empirical data that, despite this
heterogeneity, the volume-specific cerebral glucose metabolic rate of many
different brain structures scales with brain volume with almost the same
exponent around -0.15. The exception is white matter, the metabolism of which
seems to scale with a standard specific exponent -1/4. The scaling exponents
for the total oxygen and glucose consumptions in the brain in relation to its
volume are identical and equal to , which is significantly larger
than the exponents 3/4 and 2/3 suggested for whole body basal metabolism on
body mass.
Conclusions: These findings show explicitly that in mammals (i)
volume-specific scaling exponents of the cerebral energy expenditure in
different brain parts are approximately constant (except brain stem
structures), and (ii) the total cerebral metabolic exponent against brain
volume is greater than the much-cited Kleiber's 3/4 exponent. The
neurophysiological factors that might account for the regional uniformity of
the exponents and for the excessive scaling of the total brain metabolism are
discussed, along with the relationship between brain metabolic scaling and
computation.Comment: Brain metabolism scales with its mass well above 3/4 exponen
Porphyromonas gingivalis suppresses adaptive immunity in periodontitis, atherosclerosis and Alzheimerâs disease
Porphyromonas gingivalis, a keystone pathogen in chronic periodontitis, has been found to associate with remote body organ inflammatory pathologies including atherosclerosis and Alzheimerâs disease (AD). Although P. gingivalis has a plethora of virulence factors, much of its pathogenicity is surprisingly related to the overall immunosuppression of the host. This review focuses on P. gingivalis aiding suppression of the hostâs adaptive immune system involving manipulation of cellular immunological responses specifically T- and B-cells in periodontitis and related conditions. In periodontitis this bacterium inhibits the synthesis of IL-2 and increases humoral responses. This reduces inflammatory responses related to T- and B-cell activation, and subsequent IFN-É€ secretion by a subset of T cells. The T cells further suppresses upregulation of programmed cell death-1 (PD-1)-receptor on CD+-cells and its ligand PD-L1 on CD11b+- subset of T-cells. IL-2 down-regulates immune response-regulated genes, induces a cytokine pattern in which the Th17 lineage is favored thereby modulating the Th17/ T-regulatory cell (Treg) imbalance. The suppression of IFN-É€ stimulated release of interferon-inducible protein-10 (IP-10) chemokine ligands [ITAC (CXCL11) and Mig (CXCL9)] by P. gingivalis capsular serotypes, triggers distinct T-cell responses, and contributes to local immune evasion by release of its outer membrane vesicles. In atherosclerosis P. gingivalis reduces Tregs and transforming growth factor beta-1 (TGF-1) and causes imbalance in the Th17 lineage of the Treg population. In Alzheimerâs disease P. gingivalis may affect the blood-brain barrier permeability, and inhibit local IFN-É€ response by preventing entry of immune cells into the brain. The scarcity of adaptive immune cells in Alzheimerâs disease neuropathology implies P. gingivalis infection of the brain likely causes impaired clearance of insoluble amyloid and induces immunosuppression. By the effective manipulation of the armory of adaptive immune suppression through a plethora of virulence factors P. gingivalis may act as a keystone organism in periodontitis and in related systemic diseases and other remote body inflammatory pathologies
Baicalin Downregulates Porphyromonas gingivalis Lipopolysaccharide-Upregulated IL-6 and IL-8 Expression in Human Oral Keratinocytes by Negative Regulation of TLR Signaling
published_or_final_versio
Evolutionary Consequences of Altered Atmospheric Oxygen in Drosophila melanogaster
Twelve replicate populations of Drosophila melanogaster, all derived from a common ancestor, were independently evolved for 34+ generations in one of three treatment environments of varying PO2: hypoxia (5.0â10.1 kPa), normoxia (21.3 kPa), and hyperoxia (40.5 kPa). Several traits related to whole animal performance and metabolism were assayed at various stages via âcommon gardenâ and reciprocal transplant assays to directly compare evolved and acclimatory differences among treatments. Results clearly demonstrate the evolution of a greater tolerance to acute hypoxia in the hypoxia-evolved populations, consistent with adaptation to this environment. Greater hypoxia tolerance was associated with an increase in citrate synthase activity in fly homogenate when compared to normoxic (control) populations, suggesting an increase in mitochondrial volume density in these populations. In contrast, no direct evidence of increased performance of the hyperoxia-evolved populations was detected, although a significant decrease in the tolerance of these populations to acute hypoxia suggests a cost to adaptation to hyperoxia. Hyperoxia-evolved populations had lower productivity overall (i.e., across treatment environments) and there was no evidence that hypoxia or hyperoxia-evolved populations had greatest productivity or longevity in their respective treatment environments, suggesting that these assays failed to capture the components of fitness relevant to adaptation
Homogeneous search for helium in the atmosphere of 11 gas giant exoplanets with SPIRou
The metastable helium triplet in the near-infrared (10833{\AA}) is among the
most important probes of exoplanet atmospheres. It can trace their extended
outer layers and constrain mass-loss. We use the near-infrared high-resolution
spectropolarimeter SPIRou on the CFHT to search for the spectrally resolved
helium triplet in the atmospheres of eleven exoplanets, ranging from warm
mini-Neptunes to hot Jupiters and orbiting G, K, and M dwarfs. Observations
were obtained as part of the SPIRou Legacy Survey and complementary open-time
programs. We apply a homogeneous data reduction to all datasets and set
constraints on the presence of metastable helium, despite the presence of
systematics in the data. We confirm published detections for HAT-P-11b,
HD189733b, and WASP-69b and set upper limits for the other planets. We apply
the p-winds open source code to set upper limits on the mass-loss rate for the
non-detections and to constrain the thermosphere temperature, mass-loss rate,
line-of-sight velocity, and the altitude of the thermosphere for the
detections. We confirm that the presence of metastable helium correlates with
the stellar mass and the XUV flux received by the planets. We investigated the
correlation between the mass-loss rate and the presence of metastable helium,
but it remains difficult to draw definitive conclusions. Finally, some of our
results are in contradiction with previous results in the literature, therefore
we stress the importance of repeatable, homogeneous, and larger-scale analyses
of the helium triplet to obtain robust statistics, study temporal variability,
and better understand how the helium triplet can be used to explore the
evolution of exoplanets.Comment: 28 pages, 13 figures, Accepted in A&A for publicatio
In Vitro Cultivation of 'Unculturable' Oral Bacteria, Facilitated by Community Culture and Media Supplementation with Siderophores
Over a third of oral bacteria are as-yet-uncultivated in-vitro. Siderophores have been previously shown to enable in-vitro growth of previously uncultivated bacteria. The objective of this study was to cultivate novel oral bacteria in siderophore-supplemented culture media. Various compounds with siderophore activity, including pyoverdines-Fe-complex, desferricoprogen and salicylic acid, were found to stimulate the growth of difficult-to-culture strains Prevotella sp. HOT-376 and Fretibacterium fastidiosum. Furthermore, pyrosequencing analysis demonstrated increased proportions of the as-yet-uncultivated phylotypes Dialister sp. HOT-119 and Megasphaera sp. HOT-123 on mixed culture plates supplemented with siderophores. Therefore a culture model was developed, which incorporated 15 ÎŒg siderophore (pyoverdines-Fe-complex or desferricoprogen) or 150 ÎŒl neat subgingival-plaque suspension into a central well on agar plates that were inoculated with heavily-diluted subgingival-plaque samples from subjects with periodontitis. Colonies showing satellitism were passaged onto fresh plates in co-culture with selected helper strains. Five novel strains, representatives of three previously-uncultivated taxa (Anaerolineae bacterium HOT-439, the first oral taxon from the Chloroflexi phylum to have been cultivated; Bacteroidetes bacterium HOT-365; and Peptostreptococcaceae bacterium HOT-091) were successfully isolated. All novel isolates required helper strains for growth, implying dependence on a biofilm lifestyle. Their characterisation will further our understanding of the human oral microbiome
Bacteriophage Tailspikes and Bacterial OAntigens as a Model System to Study Weak-Affinity ProteinPolysaccharide Interactions
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