142 research outputs found
Utility of heavy minerals distribution and granulometric analyses in the study of coastal dynamics: Application to the littoral between Sanlúcar de Barrameda and Rota (Cadiz, southwest Iberian Peninsula)
The present paper deals with grain size and heavy minerals distribution in the sandy coastal sediments of the littoral between the cities of Sanlúcar de Barrameda and Rota. We have related these distributions to the predominant southward littoral drift and the possible source contributions, mostly represented by the Guadalquivir and Guadalete Rivers. The littoral studied is composed of fine sand in the northern sector and medium sand in its central and southern sectors. Heavy minerals were identified using X-ray analysis: the most abundant in the study area are epidote and garnet. We found that their concentrations and sizes decrease from north to south according to the coastal drift, whereas the grain morphology and the mineralogical component generally remain constant.Este trabajo trata de las distribuciones granulométrica y de minerales pesados de los sedimentos arenosos del tramo de litoral comprendido entre las ciudades de Sanlúcar de Barrameda y Rota (suroeste de la península Ibérica). Se han relacionado dichas distribuciones con la deriva litoral predominante hacia el Sur y con las fuentes de aporte de sedimentos constituidas por los ríos Guadalquivir y Guadalete. El litoral estudiado se caracteriza por arena fina en su parte norte y arena media en su parte central y meridional. Los minerales pesados se han identificado mediante rayos X: los más abundantes en el área estudiada son epidota y granate. Se ha deducido cómo sus concentraciones y tamaños disminuyen de norte a sur de acuerdo con la deriva litoral, manteniéndose el conjunto mineralógico y la morfología de los granos constante.Instituto Español de Oceanografí
Estudio arqueométrico y evaluación del deterioro de los materiales cerámicos de la fachada de la iglesia de Santa Maria del Carmine (Pavía, Italia)
We performed an archaeometric study of the ceramic materials from the façade of the church of Santa Maria del Carmine in Pavia (Italy). We obtained useful information about the firing temperatures, the provenance of raw materials and the type of oven used. The ceramics used in the façade are mineralogically rich in quartz, feldspar and phyllosilicates, and newly formed calcium silicate phases were detected in some samples. Microtextural observations revealed the presence of incipient reaction rims, phyllosilicate sintering and partial vitrification of the matrix. Ceramics show high porosity (32 to 45%) and pore sizes of between 0.4 and 1.3 µm. Our study of the different types of decay collected on the façade of the church (green and black patinas and efflorescences) revealed the presence of gypsum, whewellite, thenardite and moolooite
Degraded Carrageenan Causing Colitis in Rats Induces TNF Secretion and ICAM-1 Upregulation in Monocytes through NF-κB Activation
Carrageenan (CGN) is a high molecular weight sulphated polysaccharide derived from red seaweeds. In rodents, its degraded forms (dCGN) can induce intestinal inflammation associated with macrophage recruitment and activation. The aim of this study was: 1) to analyze the size-dependent effects of dCGN on colon inflammation in vivo, and 2) to correlate these effects with monocyte/macrophage proliferation, cytokine production and expression of various cell surface antigens including ICAM-1 adhesion molecule. Peripheral blood monocytes (PBM) and THP-1 monocytic cells were cultured in the presence of either 10 or 40 kDa, dCGN. The 40 kDa, but not the 10 kDa dCGN, induced colitis in in vivo. Degraded CGN inhibited THP-1 cell proliferation in vitro, arresting the cells in G1 phase. In addition, dCGN increased ICAM-1 expression in both PBM and THP-1 cells with a major effect seen after 40 kDa dCGN exposure. Also, dCGN stimulated monocyte aggregation in vitro that was prevented by incubation with anti-ICAM-1 antibody. Finally, dCGN stimulated TNF-α expression and secretion by both PBM and THP-1 cells. All these effects were linked to NF-κB activation. These data strongly suggest that the degraded forms of CGN have a pronounced effect on monocytes, characteristic of an inflammatory phenotype
Functional Metagenomics: A High Throughput Screening Method to Decipher Microbiota-Driven NF-κB Modulation in the Human Gut
Background/Aim: The human intestinal microbiota plays an important role in modulation of mucosal immune responses. To study interactions between intestinal epithelial cells (IECs) and commensal bacteria, a functional metagenomic approach was developed. One interest of metagenomics is to provide access to genomes of uncultured microbes. We aimed at identifying bacterial genes involved in regulation of NF-kappa B signaling in IECs. A high throughput cell-based screening assay allowing rapid detection of NF-kappa B modulation in IECs was established using the reporter-gene strategy to screen metagenomic libraries issued from the human intestinal microbiota. Methods: A plasmid containing the secreted alkaline phosphatase (SEAP) gene under the control of NF-kappa B binding elements was stably transfected in HT-29 cells. The reporter clone HT-29/kb-seap-25 was selected and characterized. Then, a first screening of a metagenomic library from Crohn's disease patients was performed to identify NF-kappa B modulating clones. Furthermore, genes potentially involved in the effect of one stimulatory metagenomic clone were determined by sequence analysis associated to mutagenesis by transposition. Results: The two proinflammatory cytokines, TNF-alpha and IL-1 beta, were able to activate the reporter system, translating the activation of the NF-kappa B signaling pathway and NF-kappa B inhibitors, BAY 11-7082, caffeic acid phenethyl ester and MG132 were efficient. A screening of 2640 metagenomic clones led to the identification of 171 modulating clones. Among them, one stimulatory metagenomic clone, 52B7, was further characterized. Sequence analysis revealed that its metagenomic DNA insert might belong to a new Bacteroides strain and we identified 2 loci encoding an ABC transport system and a putative lipoprotein potentially involved in 52B7 effect on NF-kappa B. Conclusions: We have established a robust high throughput screening assay for metagenomic libraries derived from the human intestinal microbiota to study bacteria-driven NF-kappa B regulation. This opens a strategic path toward the identification of bacterial strains and molecular patterns presenting a potential therapeutic interest
Identification of NF-κB Modulation Capabilities within Human Intestinal Commensal Bacteria
The intestinal microbiota plays an important role in modulation of mucosal immune responses. To seek interactions between intestinal epithelial cells (IEC) and commensal bacteria, we screened 49 commensal strains for their capacity to modulate NF-κB. We used HT-29/kb-seap-25 and Caco-2/kb-seap-7 intestinal epithelial cells and monocyte-like THP-1 blue reporter cells to measure effects of commensal bacteria on cellular expression of a reporter system for NF-κB. Bacteria conditioned media (CM) were tested alone or together with an activator of NF-κB to explore its inhibitory potentials. CM from 8 or 10 different commensal species activated NF-κB expression on HT-29 and Caco-2 cells, respectively. On THP-1, CM from all but 5 commensal strains stimulated NF-κB. Upon challenge with TNF-α or IL-1β, some CM prevented induced NF-κB activation, whereas others enhanced it. Interestingly, the enhancing effect of some CM was correlated with the presence of butyrate and propionate. Characterization of the effects of the identified bacteria and their implications in human health awaits further investigations
The Influence of the Type of Lime on the Hygric Behaviour and Bio-Receptivity of Hemp Lime Composites Used for Rendering Applications in Sustainable New Construction and Repair Works
The benefits of using sustainable building materials are linked not only to the adoption of manufacturing processes that entail reduced pollution, CO2 emissions and energy consumption, but also to the onset of improved performance in the building. In particular, hemp-lime composite shows low shrinkage and high thermal and acoustic insulating properties. However, this material also shows a great ability to absorb water, an aspect that can turn out to be negative for the long-term durability of the building. For this reason, the hygric properties of hemp-based composites need to be studied to ensure the correct use of this material in construction and repair works. The water absorption, drying and transpirability of hemp composites made with aerial (in the form of dry powder and putty) and hydraulic limes were investigated here and related to the microbial growth induced by the water movements within the material. Results show that hemp-natural hydraulic lime mixes exhibit the highest transpirability and drying rate, the lowest water absorption by immersion and capillary uptake and the least intense microbial attack and chromatic change. A microscopical study of the hemp shives also related their great ability to absorb water to the near-irreversible swelling of their structure under dry-wet conditions.The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 326983 (NaturALiMe), and the Spanish project MAT-2012-34473 of the Ministerio de Ciencia y Competitividad. Author MB, owner of the CANNABRIC company, had some role in the design and preparation of mortar samples and in the preparation of this manuscript, but did not have any additional role in data collection and analysis
- …