364 research outputs found
CURVED PLANFORM WINGS WITH A HIGH ASPECT RATIO FOR AIRCRAFTS OPERATING IN THE TRANSONIC REGIME
The present invention concerns an innovative
wing (1) specific for an aircraft operating in the
transonic regime and comprising:
- A root section ;
- A tip section and;
- A leading edge for connecting the root section to the tip section.
In accordance with the invention, the curved leading edge is configured according to a line by
which locally the angle (Λ) formed by the forwarding direction of the wing and the perpendicular to the
tangent of the leading edge increases progressively from the root section to the tip section of the wing.
In such a way, the speed component (Vu) of the asymptotic flow orthogonal to the leading edge decreases
progressively from the root section to the tip section, thus reducing the local Mach number progressively
Congenital mirror movements in a new Italian family
Mirror movements (MMs) occur on the contralateral side of a limb being used intentionally.
Because few families with congenital MMs and no other neurological signs have been reported, the underlying
mechanisms of MMs are still not entirely clear. We report on the clinical, genetic, neurophysiological and
neuroimaging findings of 10 of 26 living members of a novel four-generation family with congenital MMs. DCC
and RAD51 were sequenced in affected members of the family. Five of the ten subjects with MMs underwent
neurophysiological and neuroimaging evaluations. The neurophysiological evaluation consisted of
electromyographic (EMG) mirror recordings, investigations of corticospinal excitability, and analysis of
interhemispheric inhibition using transcranial magnetic stimulation techniques. The neuroimaging evaluation
included functional MRI during finger movements. Eight (all females) of the ten members examined presented
MMs of varying degrees at the clinical assessment. Transmission of MMs appears to have occurred according
to an autosomal-dominant fashion with variable expression. No mutation in DCC or RAD51 was identified. EMG
mirror activity was higher in MM subjects than in healthy controls. Short-latency interhemispheric inhibition
was reduced in MM subjects. Ipsilateral motor-evoked potentials were detectable in the most severe case.
The neuroimaging evaluation did not disclose any significant abnormalities in MM subjects. The variability of
the clinical features of this family, and the lack of known genetic abnormalities, suggests that MMs are
heterogeneous disorders. The pathophysiological mechanisms of MMs include abnormalities of transcallosal
inhibition and corticospinal decussatio
Replica symmetry breaking in mean field spin glasses trough Hamilton-Jacobi technique
During the last years, through the combined effort of the insight, coming
from physical intuition and computer simulation, and the exploitation of
rigorous mathematical methods, the main features of the mean field
Sherrington-Kirkpatrick spin glass model have been firmly established. In
particular, it has been possible to prove the existence and uniqueness of the
infinite volume limit for the free energy, and its Parisi expression, in terms
of a variational principle, involving a functional order parameter. Even the
expected property of ultrametricity, for the infinite volume states, seems to
be near to a complete proof. The main structural feature of this model, and
related models, is the deep phenomenon of spontaneous replica symmetry breaking
(RSB), discovered by Parisi many years ago. By expanding on our previous work,
the aim of this paper is to investigate a general frame, where replica symmetry
breaking is embedded in a kind of mechanical scheme of the Hamilton-Jacobi
type. Here, the analog of the "time" variable is a parameter characterizing the
strength of the interaction, while the "space" variables rule out
quantitatively the broken replica symmetry pattern. Starting from the simple
cases, where annealing is assumed, or replica symmetry, we build up a
progression of dynamical systems, with an increasing number of space variables,
which allow to weaken the effect of the potential in the Hamilton-Jacobi
equation, as the level of symmetry braking is increased. This new machinery
allows to work out mechanically the general K-step RSB solutions, in a
different interpretation with respect to the replica trick, and lightens easily
their properties as existence or uniqueness.Comment: 24 pages, no figure
Expression pattern analysis of odorant-binding proteins in the pea aphid Acyrthosiphon pisum
Odorant-binding proteins (OBPs) are soluble proteins mediating chemoreception in insects. In previous research, we investigated the molecular mechanisms adopted by aphids to detect the alarm pheromone (E)-\u3b2-farnesene and we found that the recognition of this and structurally related molecules is mediated by OBP3 and OBP7. Here, we show the differential expression patterns of 5 selected OBPs (OBP1, OBP3, OBP6, OBP7, OBP8) obtained performing quantitative RT-PCR and immunolocalization experiments in different body parts of adults and in the 5 developmental instars, including winged and unwinged morphs, of the pea aphid Acyrthosiphon pisum. The results provide an overall picture that allows us to speculate on the relationship between the differential expression of OBPs and their putative function. The expression of OBP3, OBP6, and OBP7 in the antennal sensilla suggests a chemosensory function for these proteins, whereas the constant expression level of OBP8 in all instars could suggest a conserved role. Moreover, OBP1 and OBP3 are also expressed in nonsensory organs. A light and scanning electron microscopy study of sensilla on different body parts of aphid, in particular antennae, legs, mouthparts, and cornicles-cauda, completes this research providing a guide to facilitate the mapping of OBP expression profiles
Ferromagnetic models for cooperative behavior: Revisiting Universality in complex phenomena
Ferromagnetic models are harmonic oscillators in statistical mechanics.
Beyond their original scope in tackling phase transition and symmetry breaking
in theoretical physics, they are nowadays experiencing a renewal applicative
interest as they capture the main features of disparate complex phenomena,
whose quantitative investigation in the past were forbidden due to data
lacking. After a streamlined introduction to these models, suitably embedded on
random graphs, aim of the present paper is to show their importance in a
plethora of widespread research fields, so to highlight the unifying framework
reached by using statistical mechanics as a tool for their investigation.
Specifically we will deal with examples stemmed from sociology, chemistry,
cybernetics (electronics) and biology (immunology).Comment: Contributing to the proceedings of the Conference "Mathematical
models and methods for Planet Heart", INdAM, Rome 201
Light--like Wilson loops and gauge invariance of Yang--Mills theory in 1+1 dimensions
A light-like Wilson loop is computed in perturbation theory up to for pure Yang--Mills theory in 1+1 dimensions, using Feynman and
light--cone gauges to check its gauge invariance. After dimensional
regularization in intermediate steps, a finite gauge invariant result is
obtained, which however does not exhibit abelian exponentiation. Our result is
at variance with the common belief that pure Yang--Mills theory is free in 1+1
dimensions, apart perhaps from topological effects.Comment: 10 pages, plain TeX, DFPD 94/TH/
Biocompounds recovery from Spirulina by conventional and ohmic heating methodologies: chemical and biological properties
Extracting the totality of bio-compounds with industrial interest from Cyanobacterium is often prevented by
the intrinsic rigidity of its cell wall. In this sense, the present study focuses on evaluating the influence thermal
batch extraction (conventional extraction technologies) and ohmic heating (OH) assisted extraction
(considered a greener alternative technology) in blue green microalgae Arthrospira platensis (Spirulina) cell
disruption for bioactive fractions recovery.
The proximal composition of Spirulina was initially determined. The maximum protein content (i.e., CPhycocyanin),
total carbohydrates (TC) and total phenolic compounds (TPC) extracted in water at different
times (30-120 min) and temperatures (30-51 ºC) was quantified after the conventional and OH- assisted
extraction. The freeze-thawing process was used as control. The antioxidant activity (i.e., FRAP and DPPH
assays) of the obtained extracts was assessed.
Results showed that with the freeze-thawing process, traditionally used for the recovery of bio- compounds
from Spirulina, the concentration of C-phycocyanin was approx. 42 mg/g of Spirulina, 26 mgGlcE/g Spirulina
of TC and 9 mgGAE/g Spirulina of TPC. Using OH-assisted extraction, the maximum of C-Phycocyanin
content obtained was 45 mg/g of Spirulina (obtained at 37 ºC, 30 min), the maximum carbohydrates content
was 40 mgGlcE/g Spirulina and the maximum TPC was 10 mgGAE/g Spirulina. On the other hand, using
conventional thermal treatment it can be observed that, under the same conditions, the bioactive compounds
recovery decreased to 35 mg/g, 20 mgGlcE/g Spirulina for C-phycocyanin concentration and TC (p<0.05),
respectively. The concentration in phenolic compounds is not so affected, but even so the ohmic heating
potentiates the extraction of these secondary metabolites.
The antioxidant activity of the extracts there was not different between conventional treatments andOH.
Thus, the results indicated that OH is a good alternative to conventional methods aiming at the extraction of
intracellular components with a decrease in processing time and energy costs associated with the extraction
process, which together with an easy upscale make OH an interesting methodology for use in the industrial
production of microalgae colorants and bioactive supplements.info:eu-repo/semantics/publishedVersio
Thr 163 Phosphorylation Causes Mcl-1 Stabilization when Degradation is Independent of the Adjacent GSK3-Targeted Phosphodegron, Promoting Drug Resistance in Cancer
The antiapoptotic Bcl-2 family member Mcl-1 is a PEST protein (containing sequences enriched in proline, glutamic acid, serine, and threonine) and is subject to rapid degradation via multiple pathways. Impaired degradation leading to the maintenance of Mcl-1 expression is an important determinant of drug resistance in cancer. Phosphorylation at Thr 163 in the PEST region, stimulated by 12-O-tetradecanoylphorbol acetic acid (TPA)-induced activation of extracellular signal-regulated kinase (ERK), is associated with Mcl-1 stabilization in BL41-3 Burkitt lymphoma cells. This contrasts with the observation that Thr 163 phosphorylation in normal fibroblasts primes glycogen synthase kinase (GSK3)-induced phosphorylation at Ser 159, producing a phosphodegron that targets Mcl-1 for degradation. In the present follow-up studies in BL41-3 cells, Mcl-1 degradation was found to be independent of the GSK3-mediated pathway, providing a parallel to emerging findings showing that Mcl-1 degradation through this pathway is lost in many different types of cancer. Findings in Mcl-1-transfected CHO cells corroborated those in BL41-3 cells in that the GSK3-targeted phosphodegron did not play a major role in Mcl-1 degradation, and a phosphomimetic T163E mutation resulted in marked Mcl-1 stabilization. TPA-treated BL41-3 cells, in addition to exhibiting Thr 163 phosphorylation and Mcl-1 stabilization, exhibited an ∼10-fold increase in resistance to multiple chemotherapeutic agents, including Ara-C, etoposide, vinblastine, or cisplatin. In these cancer cells in which Mcl-1 degradation is not dependent on the GSK3/phosphodegron-targeted pathway, ERK activation and Thr 163 phosphorylation are associated with pronounced Mcl-1 stabilization and drug resistance – effects that can be suppressed by inhibition of ERK activation
Mean-field cooperativity in chemical kinetics
We consider cooperative reactions and we study the effects of the interaction
strength among the system components on the reaction rate, hence realizing a
connection between microscopic and macroscopic observables. Our approach is
based on statistical mechanics models and it is developed analytically via
mean-field techniques. First of all, we show that, when the coupling strength
is set positive, the model is able to consistently recover all the various
cooperative measures previously introduced, hence obtaining a single unifying
framework. Furthermore, we introduce a criterion to discriminate between weak
and strong cooperativity, based on a measure of "susceptibility". We also
properly extend the model in order to account for multiple attachments
phenomena: this is realized by incorporating within the model -body
interactions, whose non-trivial cooperative capability is investigated too.Comment: 25 pages, 4 figure
- …