Search results for "Bioengineering"
showing 10 items of 1963 documents
Assessing theoretical flow velocity profile and resistance in gravel bed rivers by field measurements
2018
Previous studies showed that integrating a power velocity profile, deduced applying dimensional analysis and the incomplete self-similarity condition, the flow resistance equation for open channel flow can be obtained. At first, in this paper the relationship between the Gamma function of the power velocity profile, the channel slope and the Froude number, which was already empirically introduced in a previous paper, is now theoretically deduced. Then this relationship is calibrated using the field measurements of flow velocity, water depth and bed slope carried out in 101 reaches of gravel bed rivers available by literature. The proposed relationship for estimating Gamma function and the t…
Enhanced Accumulation of Betulinic Acid in Transgenic Hairy Roots of Senna obtusifolia Growing in the Sprinkle Bioreactor and Evaluation of Their Bio…
2021
Betulinic acid, which is found in transgenic roots of Senna obtusifolia (L.) H.S.Irwin & Barneby, is a pentacyclic triterpene with distinctive pharmacological activities. In this study, we report the differences in the content of betulinic acid and selected anthraquinones in transgenic S. obtusifolia hairy roots with overexpression of the PgSS1 gene (SOPSS2 line) and in transformed hairy roots without this genetic construct (SOA41 line). Both hairy root lines grew in 10 L sprinkle bioreactor. Additionally, the extracts obtained from this plant material were used for biological tests. Our results demonstrated that the SOPSS2 hairy root cultures from the bioreactor showed an increase in the c…
Yeast vectors for the integration/expression of any sequence at theTYR1 locus
2007
We have constructed new yeast vectors for targeted integration and conditional expression of any sequence at the Saccharomyces cerevisiae TYR1 locus which becomes disrupted. We show that vector integration is not neutral, causing prototrophy for tyrosine and auxotrophy for the vector's selectable marker (uracil or leucine, depending on the vector used). This feature allows a double screening of transformed yeast cells, improving the identification of colonies with the desired chromosomal structure. The GAL10 gene promoter has been added to drive conditional expression of cloned sequences. Using these vectors, chromosomal structure verification of recombinant clones is no longer necessary, s…
Acidic Monosaccharides become Incorporated into Calcite Single Crystals*.
2020
Streptococcus suis is an encapsulated bacterium and one of the most important swine pathogens and a zoonotic agent for which no effective vaccine exists. Bacterial capsular polysaccharides (CPSs) are poorly immunogenic, but anti-CPS antibodies are essential to the host defense against encapsulated bacteria. In addition to the previously known serotypes 2 and 14, that are non-immunogenic, we have recently purified and described the CPS structures for serotypes 1, 1/2, 3, 7, 8, and 9. Here, we aimed to elucidate how these new structurally diverse CPSs interact with the immune system to generate anti-CPS antibody responses. CPS-stimulated dendritic cells produced significant levels of C–C moti…
Bioactive glass ions induce efficient osteogenic differentiation of human adipose stem cells encapsulated in gellan gum and collagen type I hydrogels
2019
Abstract Background Due to unmet need for bone augmentation, our aim was to promote osteogenic differentiation of human adipose stem cells (hASCs) encapsulated in gellan gum (GG) or collagen type I (COL) hydrogels with bioactive glass (experimental glass 2-06 of composition [wt-%]: Na2O 12.1, K2O 14.0, CaO 19.8, P2O5 2.5, B2O3 1.6, SiO2 50.0) extract based osteogenic medium (BaG OM) for bone construct development. GG hydrogels were crosslinked with spermidine (GG-SPD) or BaG extract (GG-BaG). Methods Mechanical properties of cell-free GG-SPD, GG-BaG, and COL hydrogels were tested in osteogenic medium (OM) or BaG OM at 0, 14, and 21 d. Hydrogel embedded hASCs were cultured in OM or BaG OM fo…
Evaluation of nanoparticle aggregation in human blood serum.
2010
In a certain stage of development, the performance of nanoparticle- or polymer-drug conjugates is tested "in vivo", that is, in mice or rats. Besides pharmaceutical and chemical characterization, the structural characterization of such drug carrier systems in terms of size, size distribution, and shape is typically performed in physiological salt solution prior to animal tests. The present work introduces a simple method based on dynamic light scattering to monitor the particle size in blood serum. Utilizing a model system of pegylated poly-l-lysines (PLL-g-PEOx) of various degrees of pegylation, x, it is demonstrated that large aggregates may form in human serum solution that are not obser…
Aggregation behavior of cationic nanohydrogel particles in human blood serum.
2014
For systemic siRNA delivery applications, well-defined drug carriers are required that guarantee stability for both carrier and cargo. Among various concepts progressing in market or final development, cationic nanohydrogel particles may serve as novel transport media especially designed for siRNA-in vivo experiments. In this work, the interaction of nanohydrogel particles with proteins and serum components was studied via dynamic light scattering in human blood serum as novel screening method prior to applications in vivo. The formation of larger aggregates mostly caused by charge interaction with albumin could be suppressed by nanogel loading with siRNA affording a neutral zeta potential …
Tuning the surface of nanoparticles: Impact of poly(2-ethyl-2-oxazoline) on protein adsorption in serum and cellular uptake
2016
Item does not contain fulltext Due to the adsorption of biomolecules, the control of the biodistribution of nanoparticles is still one of the major challenges of nanomedicine. Poly(2-ethyl-2-oxazoline) (PEtOx) for surface modification of nanoparticles is applied and both protein adsorption and cellular uptake of PEtOxylated nanoparticles versus nanoparticles coated with poly(ethylene glycol) (PEG) and non-coated positively and negatively charged nanoparticles are compared. Therefore, fluorescent poly(organosiloxane) nanoparticles of 15 nm radius are synthesized, which are used as a scaffold for surface modification in a grafting onto approach. With multi-angle dynamic light scattering, asym…
Inhibitory Activity and Chemical Characterization ofDaucus carotasubsp.maximusEssential Oils
2017
The essential oils (EOs) of green seeds from Daucus carota subsp. maximus growing wild in Pantelleria Island (Sicily, Italy) were characterized. EOs were extracted by steam distillation, examined for their inhibitory properties against food-borne Gram-positive and Gram-negative bacteria and analyzed for the chemical composition by gas chromatography (GC) and mass spectrometry (MS). Undiluted EOs showed a large inhibition spectrum against Gram-positive strains and also vs. Acinetobacter spp. and Stenotrophomonas maltophilia. The minimum inhibition concentration (MIC) was in the range 1.25 â 2.50 μl/ml for the most sensitive strains. The chemical analysis indicated that D. carota subsp…