713 research outputs found
Assessment of coastal fish assemblages before the establishment of a new marine protected area in central Mediterranean: its role in formulating zoning proposal
The fish assemblages of the coastal area of the promontory of Cape Milazzo (Italy, Central Mediterranean), which has been recently designated by the Italian Law to become a national marine protected area (MPA), were characterized by visual censuses carried out over different habitats (rocky algal reef, Posidonia oceanica meadow and soft bottom) and depth ranges (0-3, 4-7, 12-16 and 24-30 m) to identify areas of major concern for the MPA zoning. The study area was divided into 6 sectors to assess spatial-related differences in the assemblage parameters, such as species composition and richness, and the size structure of species of recreational (e.g. SCUBA diving) interest. Fifty-eight taxa (56 species and 2 genera) and 20 families of fishes were totally recorded. Species composition was significantly affected by habitat and depth, whereas no significant changes were detected among sectors. Conversely, species richness and total density of fish showed no significant differences among sectors, habitat types and depth ranges. The majority of species of recreational value was recorded only off the northwestern part of the promontory. The implementation of fishing ban in such an area, characterized by the presence of a rocky bank, would contribute to the recovery of populations of some emblematic species (e.g. groupers and other large predator) and to the enhancement of environmentally sustainable activities such as scuba diving. Throughout the investigated area and, especially, in the eastern and southwestern coasts of the promontory, several species were almost exclusively represented by small and medium sized individuals, a likely consequence of an intense fishing pressure
Clinical and Molecular Features of Ewing Sarcoma in a Patient with Triple-X Syndrome
A case of Ewing sarcoma in a 16-year-old girl with 47 XXXc karyotype is reporte
Implementation of binary stochastic STDP learning using chalcogenide-based memristive devices
The emergence of nano-scale memristive devices encouraged many different
research areas to exploit their use in multiple applications. One of the
proposed applications was to implement synaptic connections in bio-inspired
neuromorphic systems. Large-scale neuromorphic hardware platforms are being
developed with increasing number of neurons and synapses, having a critical
bottleneck in the online learning capabilities. Spike-timing-dependent
plasticity (STDP) is a widely used learning mechanism inspired by biology which
updates the synaptic weight as a function of the temporal correlation between
pre- and post-synaptic spikes. In this work, we demonstrate experimentally that
binary stochastic STDP learning can be obtained from a memristor when the
appropriate pulses are applied at both sides of the device
Transient Posterior Encephalopathy Induced by Chemotherapy in Children
The cases of three children, 16, 12, and 12 years of age, who suffered sudden confusional state and cortical blindness lasting 12 to 30 minutes while under treatment with high-dose methotrexate, cyclophosphamide, and dactinomycin for a lower limb osteosarcoma are reported. Transient neuropsychologic deficits arose after the acute phase of treatment: left hemispatial neglect and constructive apraxia (Patient 1); constructive apraxia (Patient 2); and constructive apraxia and alexia without aphasia (Patient 3). The three patients recovered completely from all their deficits within the time frame of 3 hours to 2 weeks. Arterial hypertension and hypomagnesemia were found during the acute phase in all patients. In Patients 2 and 3, magnetic resonance imaging revealed increased parieto-occipital T(2) signal involving gray and white matter. In Patients 1 and 2, HmPAO-SPECT revealed parieto-occipital hypoperfusion that resolved a few days later. The alterations detected by neuroimaging were concurrent with the appearance and disappearance of the clinical symptoms. Such transient acute episodes have been named occipital-parietal encephalopathy. On the basis of our clinical, laboratory, and neuroimaging findings, an explanation for the origin of this syndrome, a migrainelike mechanism, triggered by chemotherapy-induced hypomagnesemia, is proposed
Pediatric Meningosarcoma: Clinical Evolution and Genetic Instability
This report presents a female diagnosed with a frontoparietal interhemispheric
meningosarcoma who, parallel to the clinical worsening, revealed an increase in
the genetic instability (in bleomycin cultures) and the complexity of the
karyotypes, with the acquisition of a clonal deletion of 17p13 (the locus for the
TP53 tumor suppressor gene). The genetic findings of this patient suggest that
the increased genetic instability could contribute to tumor progression as well
as to treatment resistance, possibly in the background of the clonal deletion of
TP53
Nonclonal Chromosomal Aberrations Induced by Anti-Tumoral Regimens in Childhood Cancer: Relationship with Cancer-Related Genes and Fragile Sites
Cytogenetic studies were performed on 80 pediatric cancer patients to observe the
chromosomal damage, both quantitative and qualitative, induced by chemotherapy.
Peripheral blood lymphocytes (PBL) (n = 127) were obtained at diagnosis, during
treatment, at remission, and at relapse, and chromosome analysis performed
utilizing G-banding standard procedures. The results show a significant increase
in the number of altered karyotypes (P = 0.03) in the samples during treatment,
returning to values that were similar to those at diagnosis at 2-year remission.
Most of the chromosomal aberrations (CA) detected during the chemotherapy
regimens were nonclonal, unbalanced (75%), and involved chromosomes 1, 3, 5, 6,
11, 12, 16, and 17 most frequently. There was also a marked increase of CA in
samples at relapse with very similar features (type and distribution) to those
detected during treatment. There was a good correlation between the chromosomal
breakpoints in our series and fragile sites (58%), oncogene (75%), and tumor
suppressor gene (33%) loci described in the literature. The results obtained
suggest that cytostatic drugs induce a transient increase in chromosome fragility
occurring at several cancer-associated breakpoints
A classical explanation of quantization
In the context of our recently developed emergent quantum mechanics, and, in
particular, based on an assumed sub-quantum thermodynamics, the necessity of
energy quantization as originally postulated by Max Planck is explained by
means of purely classical physics. Moreover, under the same premises, also the
energy spectrum of the quantum mechanical harmonic oscillator is derived.
Essentially, Planck's constant h is shown to be indicative of a particle's
"zitterbewegung" and thus of a fundamental angular momentum. The latter is
identified with quantum mechanical spin, a residue of which is thus present
even in the non-relativistic Schroedinger theory.Comment: 20 pages; version accepted for publication in Foundations of Physic
The Quantum as an Emergent System
Double slit interference is explained with the aid of what we call
"21stcentury classical physics". We model a particle as an oscillator
("bouncer") in a thermal context, which is given by some assumed "zero-point"
field of the vacuum. In this way, the quantum is understood as an emergent
system, i.e., a steady-state system maintained by a constant throughput of
(vacuum) energy. To account for the particle's thermal environment, we
introduce a "path excitation field", which derives from the thermodynamics of
the zero-point vacuum and which represents all possible paths a particle can
take via thermal path fluctuations. The intensity distribution on a screen
behind a double slit is calculated, as well as the corresponding trajectories
and the probability density current. Further, particular features of the
relative phase are shown to be responsible for nonlocal effects not only in
ordinary quantum theory, but also in our classical approach.Comment: 24 pages, 2 figures, based on a talk given at "Emergent Quantum
Mechanics (Heinz von Foerster Conference 2011)",
http://www.univie.ac.at/hvf11/congress/EmerQuM.htm
Intestinal anti-inflammatory effects of RGD-functionalized silk fibroin nanoparticles in trinitrobenzenesulfonic acid-induced experimental colitis in rats
Background: Current treatment of inflammatory bowel disease is based on the use of immunosuppressants or anti-inflammatory drugs, which are characterized by important side effects that can limit their use. Previous research has been performed by administering these drugs as nanoparticles that target the ulcerated intestinal regions and increase their bioavailability. It has been reported that silk fibroin can act as a drug carrier and shows anti-inflammatory properties. Purpose: This study was designed to enhance the interaction of the silk fibroin nanoparticles (SFNs) with the injured intestinal tissue by functionalizing them with the peptide motif RGD (arginine–glycine–aspartic acid) and to evaluate the intestinal anti-inflammatory properties of these RGD-functionalized silk fibroin nanoparticles (RGD-SFNs) in the trinitrobenzenesulfonic acid (TNBS) model of rat colitis. Materials and methods: SFNs were prepared by nanoprecipitation in methanol, and the linear RGD peptide was linked to SFNs using glutaraldehyde as the crosslinker. The SFNs (1 mg/rat) and RGD-SFNs (1 mg/rat) were administered intrarectally to TNBS-induced colitic rats for 7 days. Results: The SFN treatments ameliorated the colonic damage, reduced neutrophil infiltration, and improved the compromised oxidative status of the colon. However, only the rats treated with RGD-SFNs showed a significant reduction in the expression of different pro-inflammatory cytokines (interleukin IL]-1ß, IL-6, and IL-12) and inducible nitric oxide synthase in comparison with the TNBS control group. Moreover, the expression of both cytokine-induced neutrophil chemoattractant-1 and monocyte chemotactic protein-1 was significantly diminished by the RGD-SFN treatment. However, both treatments improved the intestinal wall integrity by increasing the gene expression of some of its markers (trefoil factor-3 and mucins). Conclusion: SFNs displayed intestinal anti-inflammatory properties in the TNBS model of colitis in rats, which were improved by functionalization with the RGD peptide
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