164 research outputs found
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
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 ÂşC) 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 ÂşC, 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
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
Granzyme B expression in visceral adipose tissue associates with local inflammation and glyco-metabolic alterations in obesity
Granzyme B (GrB) is a serine protease produced by immune and non-immune cells, able to promote multiple processes, like apoptosis, inflammation, extracellular matrix remodeling and fibrosis. GrB expression in visceral adipose tissue (VAT) was associated with tissue damage, local inflammation and insulin resistance in obesity murine model, but there is no data in humans. Aim of this study was to explore the expression of GrB in VAT from obese subjects in relation to adipose tissue injury, inflammation, metabolic alterations and GrB circulating levels. For this purpose, 85 obese individuals undergoing bariatric surgery and 35 healthy subjects (as control) were recruited at Sapienza University, Rome, Italy. Study participants underwent clinical work-up and routine biochemistry. mRNA expression of GrB in VAT and of a panel of VAT inflammatory markers was analyzed by real-time PCR. Serum GrB levels were measured by Elisa Affymetrix EBIO. We observed that 80% of obese patients expressed GrB mRNA in VAT, and GrB VAT expression was associated with the presence of local inflammation and glucose homeostasis alterations. Moreover, GrB serum levels, which were higher in obese subjects compared to non-obese healthy individuals, were associated with GrB expression in VAT and glyco-metabolic impairment. Our data show, for the first time in humans, that obese subjects with “sick” fat and altered glucose tolerance exhibit GrB expression in VAT, and suggest that GrB might contribute to obesity-related VAT inflammatory remodeling and glucose homeostasis dysregulation. Moreover, increased circulating GrB levels might represent a possible peripheral marker of VAT dysfunction in metabolic diseases
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
The Italian tremor Network (TITAN): rationale, design and preliminary findings.
INTRODUCTION: The recently released classification has revised the nosology of tremor, defining essential tremor (ET) as a syndrome and fueling an enlightened debate about some newly conceptualized entities such as ET-plus. As a result, precise information of demographics, clinical features, and about the natural history of these conditions are lacking. METHODS: The ITAlian tremor Network (TITAN) is a multicenter data collection platform, the aim of which is to prospectively assess, according to a standardized protocol, the phenomenology and natural history of tremor syndromes. RESULTS: In the first year of activity, 679 patients have been recruited. The frequency of tremor syndromes varied from 32% of ET and 41% of ET-plus to less than 3% of rare forms, including focal tremors (2.30%), task-specific tremors (1.38%), isolated rest tremor (0.61%), and orthostatic tremor (0.61%). Patients with ET-plus were older and had a higher age at onset than ET, but a shorter disease duration, which might suggest that ET-plus is not a disease stage of ET. Familial aggregation of tremor and movement disorders was present in up to 60% of ET cases and in about 40% of patients with tremor combined with dystonia. The body site of tremor onset was different between tremor syndromes, with head tremor being most commonly, but not uniquely, associated with dystonia. CONCLUSIONS: The TITAN study is anticipated to provide clinically relevant prospective information about the clinical correlates of different tremor syndromes and their specific outcomes and might serve as a basis for future etiological, pathophysiological, and therapeutic research
Artificial intelligence of imaging and clinical neurological data for predictive, preventive and personalized (P3) medicine for Parkinson Disease: the NeuroArtP3 protocol for a multi-center research study
Background
The burden of Parkinson Disease (PD) represents a key public health issue and it is essential to develop innovative and cost-effective approaches to promote sustainable diagnostic and therapeutic interventions. In this perspective the adoption of a P3 (predictive, preventive and personalized) medicine approach seems to be pivotal. The NeuroArtP3 (NET-2018-12366666) is a four-year multi-site project co-funded by the Italian Ministry of Health, bringing together clinical and computational centers operating in the field of neurology, including PD.
Objective
The core objectives of the project are: i) to harmonize the collection of data across the participating centers, ii) to structure standardized disease-specific datasets and iii) to advance knowledge on disease’s trajectories through machine learning analysis.
Methods
The 4-years study combines two consecutive research components: i) a multi-center retrospective observational phase; ii) a multi-center prospective observational phase. The retrospective phase aims at collecting data of the patients admitted at the participating clinical centers. Whereas the prospective phase aims at collecting the same variables of the retrospective study in newly diagnosed patients who will be enrolled at the same centers.
Results
The participating clinical centers are the Provincial Health Services (APSS) of Trento (Italy) as the center responsible for the PD study and the IRCCS San Martino Hospital of Genoa (Italy) as the promoter center of the NeuroartP3 project. The computational centers responsible for data analysis are the Bruno Kessler Foundation of Trento (Italy) with TrentinoSalute4.0 –Competence Center for Digital Health of the Province of Trento (Italy) and the LISCOMPlab University of Genoa (Italy).
Conclusions
The work behind this observational study protocol shows how it is possible and viable to systematize data collection procedures in order to feed research and to advance the implementation of a P3 approach into the clinical practice through the use of AI models
Broadband Dielectric Spectroscopy on Human Blood
Dielectric spectra of human blood reveal a rich variety of dynamic processes.
Achieving a better characterization and understanding of these processes not
only is of academic interest but also of high relevance for medical
applications as, e.g., the determination of absorption rates of electromagnetic
radiation by the human body. The dielectric properties of human blood are
studied using broadband dielectric spectroscopy, systematically investigating
the dependence on temperature and hematocrit value. By covering a frequency
range from 1 Hz to 40 GHz, information on all the typical dispersion regions of
biological matter is obtained. We find no evidence for a low-frequency
relaxation (alpha-relaxation) caused, e.g., by counterion diffusion effects as
reported for some types of biological matter. The analysis of a strong
Maxwell-Wagner relaxation arising from the polarization of the cell membranes
in the 1-100 MHz region (beta-relaxation) allows for the test of model
predictions and the determination of various intrinsic cell properties. In the
microwave region beyond 1 GHz, the reorientational motion of water molecules in
the blood plasma leads to another relaxation feature (gamma-relaxation).
Between beta- and gamma-relaxation, significant dispersion is observed, which,
however, can be explained by a superposition of these relaxation processes and
is not due to an additional delta-relaxation often found in biological matter.
Our measurements provide dielectric data on human blood of so far unsurpassed
precision for a broad parameter range. All data are provided in electronic form
to serve as basis for the calculation of the absorption rate of electromagnetic
radiation and other medical purposes. Moreover, by investigating an
exceptionally broad frequency range, valuable new information on the dynamic
processes in blood is obtained.Comment: 17 pages, 9 figure
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