145 research outputs found
Immunoreactivity of gluten-sensitized sera toward wheat, rice, corn, and Amaranth flour proteins treated with microbial transglutaminase
The aim of this study was to analyze the effects of microbial transglutaminase (mTG) on the immunoreactivity of wheat and gluten-free cereals flours to the sera of patients with celiac disease (CD) and non-celiac gluten sensitivity (NCGS). Both doughs and sourdoughs, the latter prepared by a two-step fermentation with Lactobacillus sanfranciscensis and Candida milleri, were studied. In order to evaluate the IgG-binding capacity toward the proteins of the studied flours, total protein as well as protein fractions enriched in albumins/globulins, prolamins and glutelins, were analyzed by SDS-PAGE and enzyme-linked immunosorbent assay (ELISA). Results showed that while mTG modified both gluten and gluten-free flour by increasing the amount of cross-linked proteins, it did not affect the serum's immune-recognition. In fact, no significant differences were observed in the immunoreactivity of sera from CD and NCGS patients toward wheat and gluten-free protein extracts after enzyme treatment, nor did this biotechnological treatment affect the immunoreactivity of control samples or the sera of healthy patients. These results suggest that mTG may be used as a tool to create innovative gluten and gluten-free products with improved structural properties, without increasing the immune-reactivity toward proteins present either in doughs or in sourdoughs
Public perception and knowledge on nanotechnology: A study based on a citizen science approach
Even with the widespread use of nanomaterials (NMs) in everyday life, consumer knowledge about the functionality, benefits, and possible dangers of nanotechnology (NT) is still modest. As with any developing technology, its public perception has direct implications on future policies and has to be taken into account by academia and industry alike. As part of the “Nan-O-Style” interdisciplinary research project, an online survey was conducted using a Citizen Science-guided approach. The main goal was to evaluate the current levels of knowledge and the attitude towards NT among the general Austrian public and to determine how differing sociodemographic factors may affect these. Over the course of 17 months, a total of 1067 responses were collected and quantitatively analysed. We found that while Austrians display a generally optimistic view and a positive attitude towards NT, there are still remaining concerns about its safety and possible risks. Participants expressed great desire for more information about NT and its applications, as well as for clear labelling and transparency of products containing NMs. Notably, we found that age did not affect the general attitude towards NT nor the levels of NT awareness. While participants with a university degree were generally more knowledgeable on this specific topic, surprisingly, there were no significant differences in the attitude towards NT among people from different educational backgrounds. Similar to previous studies, we observed that male participants demonstrated a more positive attitude towards NT and scored slightly higher in our NT quiz compared to female participants. However, female participants voiced greater desire for more information and transparency regarding NMs. Interestingly, while participants with a negative attitude towards NT scored lowest on the NT quiz, they also expressed the least interest in receiving more NT-related information. This illustrates a difficulty in mitigating public aversion solely by providing more information
Electron-Phonon Coupling in High-Temperature Cuprate Superconductors Determined from Electron Relaxation Rates
We determined electronic relaxation times via pump-probe optical spectroscopy
using sub-15 fs pulses for the normal state of two different cuprate
superconductors.We show that the primary relaxation process is the
electron-phonon interaction and extract a measure of its strength, the second
moment of the Eliashberg function\lambda=800\pm200 meV^{2} for
La_{1.85}Sr_{0.15}CuO_{4} and \lambda=400\pm100 meV^{2} for
YBa_{2}Cu_{3}O_{6.5}. These values suggest a possible fundamental role of the
electron-phonon interaction in the superconducting pairing mechanism.Comment: As published in PR
Disentangling the electronic and phononic glue in a high-Tc superconductor
Unveiling the nature of the bosonic excitations that mediate the formation of
Cooper pairs is a key issue for understanding unconventional superconductivity.
A fundamen- tal step toward this goal would be to identify the relative weight
of the electronic and phononic contributions to the overall frequency (\Omega)
dependent bosonic function, \Pi(\Omega). We perform optical spectroscopy on
Bi2212 crystals with simultaneous time- and frequency-resolution; this
technique allows us to disentangle the electronic and phononic contributions by
their different temporal evolution. The strength of the interaction
({\lambda}~1.1) with the electronic excitations and their spectral distribution
fully account for the high critical temperature of the superconducting phase
transition.Comment: 9 pages, 4 figure
Diamagnetism of real-space pairs above Tc in hole doped cuprates
The nonlinear normal state diamagnetism reported by Lu Li et al. [Phys. Rev.
B 81, 054510 (2010)] is shown to be incompatible with an acclaimed Cooper
pairing and vortex liquid above the resistive critical temperature. Instead it
is perfectly compatible with the normal state Landau diamagnetism of real-space
composed bosons, which describes the nonlinear magnetization curves in less
anisotropic cuprates La-Sr-Cu-O (LSCO) and Y-Ba-Cu-O (YBCO) as well as in
strongly anisotropic bismuth-based cuprates in the whole range of available
magnetic fields.Comment: 4 pages, 4 figure
Effect of screening of the electron-phonon interaction on the temperature of Bose-Einstein condensation of intersite bipolarons
Here we consider an interacting electron-phonon system within the framework
of extended Holstein-Hubbard model at strong enough electron-phonon interaction
limit in which (bi)polarons are the essential quasiparticles of the system. It
is assumed that the electron-phonon interaction is screened and its potential
has Yukawa-type analytical form. An effect of screening of the electron-phonon
interaction on the temperature of Bose-Einstein condensation of the intersite
bipolarons is studied for the first time. It is revealed that the temperature
of Bose-Einstein condensation of intersite bipolarons is higher in the system
with the more screened electron-phonon interaction.Comment: 6 pages, 4 figure
Strain-induced enhancement of the electron energy relaxation in strongly correlated superconductors
We use femtosecond optical spectroscopy to systematically measure the primary
energy relaxation rate k1 of photoexcited carriers in cuprate and pnictide
superconductors. We find that k1 increases monotonically with increased
negative strain in the crystallographic a-axis. Generally, the Bardeen-Shockley
deformation potential theorem and, specifically, pressure-induced Raman shifts
reported in the literature suggest that increased negative strain enhances
electron-phonon coupling, which implies that the observed direct correspondence
between a and k1 is consistent with the canonical assignment of k1 to the
electron-phonon interaction. The well-known non-monotonic dependence of the
superconducting critical temperature Tc on the a-axis strain is also reflected
in a systematic dependence Tc on k1, with a distinct maximum at intermediate
values (~16 ps-1 at room temperature). The empirical non-monotonic systematic
variation of Tc with the strength of the electron-phonon interaction provides
us with unique insight into the role of electron-phonon interaction in relation
to the mechanism of high-Tc superconductivity as a crossover phenomenon.Comment: manuscript as accepted in PRX, main paper (20 pages, 3 figures) plus
supplementary material (25 pages, 19 figures
Exciton bimolecular annihilation dynamics in supramolecular nanostructures of conjugated oligomers
We present femtosecond transient absorption measurements on -conjugated
supramolecular assemblies in a high pump fluence regime.
Oligo(\emph{p}-phenylenevinylene) monofunctionalized with
ureido-\emph{s}-triazine (MOPV) self-assembles into chiral stacks in dodecane
solution below 75C at a concentration of M. We
observe exciton bimolecular annihilation in MOPV stacks at high excitation
fluence, indicated by the fluence-dependent decay of B-exciton
spectral signatures, and by the sub-linear fluence dependence of time- and
wavelength-integrated photoluminescence (PL) intensity. These two
characteristics are much less pronounced in MOPV solution where the phase
equilibrium is shifted significantly away from supramolecular assembly,
slightly below the transition temperature. A mesoscopic rate-equation model is
applied to extract the bimolecular annihilation rate constant from the
excitation fluence dependence of transient absorption and PL signals. The
results demonstrate that the bimolecular annihilation rate is very high with a
square-root dependence in time. The exciton annihilation results from a
combination of fast exciton diffusion and resonance energy transfer. The
supramolecular nanostructures studied here have electronic properties that are
intermediate between molecular aggregates and polymeric semiconductors
Sensitization Prevalence, Antibody Cross-Reactivity and Immunogenic Peptide Profile of Api g 2, the Non-Specific Lipid Transfer Protein 1 of Celery
Background: Celery (Apium graveolens) represents a relevant allergen source that can elicit severe reactions in the adult population. To investigate the sensitization prevalence and cross-reactivity of Api g 2 from celery stalks in a Mediterranean population and in a mouse model. Methodology: 786 non-randomized subjects from Italy were screened for IgE reactivity to rApi g 2, rArt v 3 (mugwort pollen LTP) and nPru p 3 (peach LTP) using an allergen microarray. Clinical data of 32 selected patients with reactivity to LTP under investigation were evaluated. Specific IgE titers and cross-inhibitions were performed in ELISA and allergen microarray. Balb/c mice were immunized with purified LTPs; IgG titers were determined in ELISA and mediator release was examined using RBL-2H3 cells. Simulated endolysosomal digestion was performed using microsomes obtained from human DCs. Results: IgE testing showed a sensitization prevalence of 25.6% to Api g 2, 18.6% to Art v 3, and 28.6% to Pru p 3 and frequent co-sensitization and correlating IgE-reactivity was observed. 10/32 patients suffering from LTP-related allergy reported symptoms upon consumption of celery stalks which mainly presented as OAS. Considerable IgE cross-reactivity was observed between Api g 2, Art v 3, and Pru p 3 with varying inhibition degrees of individual patients' sera. Simulating LTP mono-sensitization in a mouse model showed development of more congruent antibody specificities between Api g 2 and Art v 3. Notably, biologically relevant murine IgE cross-reactivity was restricted to the latter and diverse from Pru p 3 epitopes. Endolysosomal processing of LTP showed generation of similar clusters, which presumably represent T-cell peptides. Conclusions: Api g 2 represents a relevant celery stalk allergen in the LTP-sensitized population. The molecule displays common B cell epitopes and endolysosomal peptides that encompass T cell epitopes with pollen and plant-food derived LTP.Christian-Doppler Research Association, Biomay AG, Vienna, AustriaItalian Ministry of Healt
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