Search results for "POLYMER"
showing 10 items of 10504 documents
Influence of the Fabrication Accuracy of Hot-Embossed PCL Scaffolds on Cell Growths
2020
Polycaprolactone (PCL) is a biocompatible and biodegradable polymer widely used for the realization of 3D scaffold for tissue engineering applications. The hot embossing technique (HE) allows the obtainment of PCL scaffolds with a regular array of micro pillars on their surface. The main drawback affecting this kind of micro fabrication process is that such structural superficial details can be damaged when detaching the replica from the mold. Therefore, the present study has focused on the optimization of the HE processes through the development of an analytical model for the prediction of the demolding force as a function of temperature. This model allowed calculating the minimum demoldin…
3D printing of hybrid biomaterials for bone tissue engineering: Calcium-polyphosphate microparticles encapsulated by polycaprolactone.
2017
Abstract Here we describe the formulation of a morphogenetically active bio-ink consisting of amorphous microparticles (MP) prepared from Ca 2+ and the physiological inorganic polymer, polyphosphate (polyP). Those MP had been fortified by mixing with poly-e-caprolactone (PCL) to allow 3D-bioprinting. The resulting granular PCL/Ca-polyP-MP hybrid material, liquefied by short-time heating to 100 °C, was used for the 3D-printing of tissue-like scaffolds formed by strands with a thickness of 400 µm and a stacked architecture leaving ≈0.5 mm 2 -sized open holes enabling cell migration. The printed composite scaffold turned out to combine suitable biomechanical properties (Young’s modulus of 1.60…
Validation and implementation of a commercial real-time PCR assay for direct detection of Candida auris from surveillance samples.
2021
Background Rapid and reliable laboratory methods are required for detecting the nosocomial yeast Candida auris. AurisID® (Olm Diagnostics, England) is a real-time PCR assay approved for detecting C. auris in fungal cultures as well as directly from blood samples, involving a nucleic acid extraction as a prior step. Objectives The purpose of this study is to validate the AurisID® kit for direct detection of C. auris from surveillance samples without prior DNA extraction and to analyze the results of implementing this methodology to our daily laboratory routine protocol for C. auris surveillance studies. Methods Our PCR method using the AurisID® kit was compared with our routine protocol, con…
Diversity, virulence, and antimicrobial resistance of the KPC-producing Klebsiella pneumoniae ST307 clone
2017
ABSTRACT : The global spread of Klebsiella pneumoniae producing Klebsiella pneumoniae carbapenemase (KPC) has been mainly associated with the dissemination of high-risk clones. In the last decade, hospital outbreaks involving KPC-producing K. pneumoniae have been predominantly attributed to isolates belonging to clonal group (CG) 258. However, results of recent epidemiological analysis indicate that KPC-producing sequence type (ST) 307, is emerging in different parts of the world and is a candidate to become a prevalent high-risk clone in the near future. Here we show that the ST307 genome encodes genetic features that may provide an advantage in adaptation to the hospital environment and t…
Isolation of lactic acid-forming bacteria from biogas plants.
2017
Direct molecular approaches provide hints that lactic acid bacteria play an important role in the degradation process of organic material to methanogenetic substrates in biogas plants. However, their diversity in biogas fermenter samples has not been analyzed in detail yet. For that reason, five different biogas fermenters, which were fed mainly with maize silage and manure from cattle or pigs, were examined for the occurrence of lactic acid-forming bacteria. A total of 197 lactic acid-forming bacterial strains were isolated, which we assigned to 21 species, belonging to the genera Bacillus, Clostridium, Lactobacillus, Pediococcus, Streptococcus and Pseudoramibacter-related. A qualitative m…
L1-Penalized Censored Gaussian Graphical Model
2018
Graphical lasso is one of the most used estimators for inferring genetic networks. Despite its diffusion, there are several fields in applied research where the limits of detection of modern measurement technologies make the use of this estimator theoretically unfounded, even when the assumption of a multivariate Gaussian distribution is satisfied. Typical examples are data generated by polymerase chain reactions and flow cytometer. The combination of censoring and high-dimensionality make inference of the underlying genetic networks from these data very challenging. In this article, we propose an $\ell_1$-penalized Gaussian graphical model for censored data and derive two EM-like algorithm…
AFS: identification and quantification of species composition by metagenomic sequencing
2017
Abstract Summary DNA-based methods to detect and quantify taxon composition in biological materials are often based on species-specific polymerase chain reaction, limited to detecting species targeted by the assay. Next-generation sequencing overcomes this drawback by untargeted shotgun sequencing of whole metagenomes at affordable cost. Here we present AFS, a software pipeline for quantification of species composition in food. AFS uses metagenomic shotgun sequencing and sequence read counting to infer species proportions. Using Illumina data from a reference sausage comprising four species, we reveal that AFS is independent of the sequencing assay and library preparation protocol. Cost-sav…
Inhabiting plant roots, nematodes, and truffles—polyphilus, a new helotialean genus with two globally distributed species
2018
Fungal root endophytes, including the common group of dark septate endophytes (DSEs), represent different taxonomic groups and potentially diverse life strategies. In this study, we investigated two unidentified helotialean lineages found previously in a study of DSE fungi of semiarid grasslands, from several other sites, and collected recently from a pezizalean truffle ascoma and eggs of the cereal cyst nematode Heterodera filipjevi. The taxonomic positions and phylogenetic relationships of 21 isolates with different hosts and geographic origins were studied in detail. Four loci, namely, nuc rDNA ITS1-5.8S-ITS2 (internal transcribed spacer [ITS]), partial 28S nuc rDNA (28S), partial 18S nu…
The mRNA cap-binding protein Cbc1 is required for high and timely expression of genes by promoting the accumulation of gene-specific activators at pr…
2015
The highly conserved Saccharomyces cerevisiae cap-binding protein Cbc1/Sto1 binds mRNA co-transcriptionally and acts as a key coordinator of mRNA fate. Recently, Cbc1 has also been implicated in transcription elongation and pre-initiation complex (PIC) formation. Previously, we described Cbc1 to be required for cell growth under osmotic stress and to mediate osmostress-induced translation reprogramming. Here, we observe delayed global transcription kinetics in cbc1Δ during osmotic stress that correlates with delayed recruitment of TBP and RNA polymerase II to osmo-induced promoters. Interestingly, we detect an interaction between Cbc1 and the MAPK Hog1, which controls most gene expression c…
Bronchial inflammation and bacterial load in stable COPD is associated with TLR4 overexpression.
2017
Toll-like receptors (TLRs) and nucleotide-binding oligomerisation domain (NOD)-like receptors (NLRs) are two major forms of innate immune sensors but their role in the immunopathology of stable chronic obstructive pulmonary disease (COPD) is incompletely studied. Our objective here was to investigate TLR and NLR signalling pathways in the bronchial mucosa in stable COPD.Using immunohistochemistry, the expression levels of TLR2, TLR4, TLR9, NOD1, NOD2, CD14, myeloid differentiation primary response gene 88 (MyD88), Toll-interleukin-1 receptor domain-containing adaptor protein (TIRAP), and the interleukin-1 receptor-associated kinases phospho-IRAK1 and IRAK4 were measured in the bronchial muc…