Nonmicrobial activation of TLRs controls intestinal growth, wound repair, and radioprotection

TLRs, key components of the innate immune system, recognize microbial molecules. However, TLRs also recognize some nonmicrobial molecules. In particular, TLR2 and TLR4 recognize hyaluronic acid, a glycosaminoglycan in the extracellular matrix. In neonatal mice endogenous hyaluronic acid binding to TLR4 drives normal intestinal growth. Hyaluronic acid binding to TLR4 in pericryptal macrophages results in cyclooxygenase2- dependent PG

Highly conserved type 1 pili promote enterotoxigenic E. coli pathogen-host interactions

Enterotoxigenic Escherichia coli (ETEC), defined by their elaboration of heat-labile (LT) and/or heat-stable (ST) enterotoxins, are a common cause of diarrheal illness in developing countries. Efficient delivery of these toxins requires ETEC to engage target host enterocytes. This engagement is accomplished using a variety of pathovar-specific and conserved E. coli adhesin molecules as well as plasmid encoded colonization factors. Some of these adhesins undergo significant transcriptional modulation as ETEC encounter intestinal epithelia, perhaps suggesting that they cooperatively facilitate interaction with the host. Among genes significantly upregulated on cell contact are those encoding type 1 pili. We therefore investigated the role played by these pili in facilitating ETEC adhesion, and toxin delivery to model intestinal epithelia. We demonstrate that type 1 pili, encoded in the E. coli core genome, play an essential role in ETEC virulence, acting in concert with plasmid-encoded pathovar specific colonization factor (CF) fimbriae to promote optimal bacterial adhesion to cultured intestinal epithelium (CIE) and to epithelial monolayers differentiated from human small intestinal stem cells. Type 1 pili are tipped with the FimH adhesin which recognizes mannose with stereochemical specificity. Thus, enhanced production of highly mannosylated proteins on intestinal epithelia promoted FimH-mediated ETEC adhesion, while conversely, interruption of FimH lectin-epithelial interactions with soluble mannose, anti-FimH antibodies or mutagenesis of fimH effectively blocked ETEC adhesion. Moreover, fimH mutants were significantly impaired in delivery of both heat-stable and heat-labile toxins to the target epithelial cells in vitro, and these mutants were substantially less virulent in rabbit ileal loop assays, a classical model of ETEC pathogenesis. Collectively, our data suggest that these highly conserved pili play an essential role in virulence of these diverse pathogens

Bilateral osseous stenosis of the internal auditory canal: case report

Osteomas as well as exostoses of the internal auditory canal are rare, benign, usually slow-growing lesions. The most common localizations of these temporal bone lesions are the mastoid cortex and the external auditory canal. A rare case is reported of bilateral osseous stenosis of the internal auditory canal, in the absence of clinical (auditory, vestibular and facial nerve) symptoms. In the absence of auditory, vestibular and/or facial nerve symptoms, long-term follow-up should be assessed; surgical intervention may be warranted only if symptoms are present

Blood Group O-Dependent cellular responses to cholera toxin: Parallel clinical and epidemiological links to severe cholera

Because O blood group has been associated with more severe cholera infections, it has been hypothesized that cholera toxin (CT) may bind non-O blood group antigens of the intestinal mucosae, thereby preventing efficient interaction with target GM1 gangliosides required for uptake of the toxin and activation of cyclic adenosine monophosphate (cAMP) signaling in target epithelia. Herein, we show that after exposure to CT, human enteroids expressing O blood group exhibited marked increase in cAMP relative to cells derived from blood group A individuals. Likewise, using CRISPR/Cas9 engineering, a functional group O line (HT-29-A(−/−)) was generated from a parent group A HT-29 line. CT stimulated robust cAMP responses in HT-29-A(−/−) cells relative to HT-29 cells. These findings provide a direct molecular link between blood group O expression and differential cellular responses to CT, recapitulating clinical and epidemiologic observations

Sustainable exploitation of residual cynara cardunculus l. To levulinic acid and n-butyl levulinate

Hydrolysis and butanolysis of lignocellulosic biomass are efficient routes to produce two valuable bio-based platform chemicals, levulinic acid and n-butyl levulinate, which find increasing applications in the field of biofuels and for the synthesis of intermediates for chemical and pharmaceutical industries, food additives, surfactants, solvents and polymers. In this research, the ac-id-catalyzed hydrolysis of the waste residue of Cynara cardunculus L. (cardoon), remaining after seed removal for oil exploitation, was investigated. The cardoon residue was employed as-received and after a steam-explosion treatment which causes an enrichment in cellulose. The effects of the main reaction parameters, such as catalyst type and loading, reaction time, temperature and heat-ing methodology, on the hydrolysis process were assessed. Levulinic acid molar yields up to about 50 mol % with levulinic acid concentrations of 62.1 g/L were reached. Moreover, the one-pot bu-tanolysis of the steam-exploded cardoon with the bio-alcohol n-butanol was investigated, demon-strating the direct production of n-butyl levulinate with good yield, up to 42.5 mol %. These results demonstrate that such residual biomass represent a promising feedstock for the sustainable production of levulinic acid and n-butyl levulinate, opening the way to the complete exploitation of this crop

Field emission properties of carbon nanotube arrays grown in porous anodic alumina

AbstractCarbon nanotubes (CNTs), with their excellent electronic properties and extremely high aspect ratio, represent an ideal material for building electron sources based on field emission. Fowler‐Nordheim equation describes quite successfully the field emission phenomenon, especially for single or isolated tips. However, some complications arise when populations of CNTs are considered, where collective effects and large variability in the emitters features influence the measured I–V characteristics. In this work, the emission properties of multi‐walled CNTs grown within ordered anodic alumina templates are investigated. These CNT matrices produce current densities up to some tens of mA/cm2, and the field enhancement factor for collective emission sources can be estimated. Such material can be modelled as an ordered and uniform array of emitters and a simulation of the electrostatic field on the emission tips can be done in order to evaluate the field enhancement factor and its dependence on various geometries. This allows comparing predictions from simulation and experimental measurements, in a direct way. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim

A prototype model for evaluating SKA-LOW station calibration

The Square Kilometre Array telescope at low-frequency (SKA-Low) will be a phased array telescope supporting a wide range of science cases covering the frequency band 50 - 350 MHz, while at the same time asking for high sensitivity and excellent characteristics. These extremely challenging requirements resulted in a design using 512 groups of 256 log periodic dual polarized antennas each (where each group is called “station”), for a total of 131072 antennas. The 512 stations are randomly distributed mostly within a dense area around the centre of the SKA-Low, and then in 3 arms having 16 station clusters each. In preparation for the SKA Phase 1 (SKA1) System Critical Design Review (CDR), prototype stations were deployed at the Murchison Radio-astronomy Observatory (MRO) site (Western Australia) near the Murchison Widefield Array (MWA) radio telescope. The project involved multiple parties in an International collaboration building and testing different prototypes of the SKA1-Low station near the actual site. This resulted in both organisational and logistic challenges typical of a deployment of the actual telescope. The test set-up involved a phased build-up of the complex station of log-periodic antennas, by starting from the deployment of 48 antennas and related station signal processing (called AAVS1.5, where AAVS stands for Aperture Array Verification System), followed by expansion to a full station (AAVS2.0). As reference a station with dipole antennas EDA2 (EDA: Engineering Development Array) was deployed. This test set-up was used for an extensive test and evaluation programme. All test antenna configurations were simulated in detail by electromagnetic (EM) models, and the prediction of the models was further verified by appropriate tests with a drone-based radio frequency source. Astronomical observations on Sun and galaxy transit were performed with calibrated stations of both EDA2, AAVS1.5 and AAVS2.0. All 3 configurations were calibrated. EM modelling and calibration results for the full station AAVS2.0 and EM verification for the AAVS1.5 station are presented. The comparisons between the behaviour of the log-periodic antennas and the dipoles have advanced our understanding the calibration quality and the technological maturity of the future SKA1-Low array

Characteristic Mode Analysis of Multi-Octave Asymmetric Dipoles

This paper discusses the impedance and front-to-back ratio performance of asymmetric dipoles. These parameters are very important when the antennas are placed over a conductive ground plane and should operate over multi-octave frequency bands. The operation of these antennas is usually described relying on analogies with more classical structures such as symmetric dipoles and tapered slot antennas. To provide a solid theoretical background to this intuition, this work presents the application of characteristic mode analysis to multi-octave dipole antennas. Firstly, a brief review of the main characteristic mode content is presented. Then, characteristic mode analysis is applied to three antenna concepts to emphasize how their geometry impacts on the relevant figures of merit. This allows to draw some conclusions on the achievable performance by different designs

First Results on the Experimental Validation of the SKA-low Prototypes Deployed in Australia Using an Airborne Test Source

As the Square Kilometre Array progresses toward the construction phase, the first prototypes of the low-frequency instrument have been deployed in Australia. To support such a crucial phase, a measurement campaign took place in the Murchison Radio-astronomy Observatory area in order to validate the electromagnetic models of the arrays by characterizing the embedded-element patterns and the array beams. A set of significant results is shown in this contribution