395 research outputs found
A Derivation of Three-Dimensional Inertial Transformations
The derivation of the transformations between inertial frames made by
Mansouri and Sexl is generalised to three dimensions for an arbitrary direction
of the velocity. Assuming lenght contraction and time dilation to have their
relativistic values, a set of transformations kinematically equivalent to
special relativity is obtained. The ``clock hypothesis'' allows the derivation
to be extended to accelerated systems. A theory of inertial transformations
maintaining an absolute simultaneity is shown to be the only one logically
consistent with accelerated movements. Algebraic properties of these
transformations are discussed. Keywords: special relativity, synchronization,
one-way velocity of light, ether, clock hypothesis.Comment: 16 pages (A5), Latex, one figure, to be published in Found. Phys.
Lett. (1997
Molecular mechanisms of mtdna-mediated inflammation
Besides their role in cell metabolism, mitochondria display many other functions. Mitochondrial DNA (mtDNA), the own genome of the organelle, plays an important role in modulating the inflammatory immune response. When released from the mitochondrion to the cytosol, mtDNA is recognized by cGAS, a cGAMP which activates a pathway leading to enhanced expression of type I interferons, and by NLRP3 inflammasome, which promotes the activation of pro-inflammatory cytokines Interleukin-1beta and Interleukin-18. Furthermore, mtDNA can be bound by Toll-like receptor 9 in the endosome and activate a pathway that ultimately leads to the expression of pro-inflammatory cytokines. mtDNA is released in the extracellular space in different forms (free DNA, protein-bound DNA fragments) either as free circulating molecules or encapsulated in extracellular vesicles. In this review, we discussed the latest findings concerning the molecular mechanisms that regulate the release of mtDNA from mitochondria, and the mechanisms that connect mtDNA misplacement to the activation of inflammation in different pathophysiological conditions
Mitochondrial DNA and exercise: Implications for health and injuries in sports
Recently, several studies have highlighted the tight connection between mitochondria and physical activity. Mitochondrial functions are important in high-demanding metabolic activities, such as endurance sports. Moreover, regular training positively affects metabolic health by increasing mitochondrial oxidative capacity and regulating glucose metabolism. Exercise could have multiple effects, also on the mitochondrial DNA (mtDNA) and vice versa; some studies have investigated how mtDNA polymorphisms can affect the performance of general athletes and mtDNA haplogroups seem to be related to the performance of elite endurance athletes. Along with several stimuli, including pathogens, stress, trauma, and reactive oxygen species, acute and intense exercise also seem to be responsible for mtDNA release into the cytoplasm and extracellular space, leading to the activation of the innate immune response. In addition, several sports are characterized by a higher frequency of injuries, including cranial trauma, associated with neurological consequences. However, with regular exercise, circulating cell-free mtDNA levels are kept low, perhaps promoting cf-mtDNA removal, acting as a protective factor against inflammation
Characterization of a bean landrace from Sicily: the ‘fagiolo Badda di Polizzi'
Inside the project “Piano per la Produzione di Proteine Vegetali in Sicilia” investigations were
carried out to characterize a bean population cultivated in the Parco delle Madonie area, the
‘Fagiolo Badda di Polizzi’. The producers’ interest for this landrace and the appreciation of the
consumers could justify the start up of a valorization program through a product certification.
Researches on the morpho-physiological aspects and on the nutritional profile were made in
trials conducted between 2005 and 2007. All the Badda bean accessions showed an indeterminate
plant growth habit, white flowers and a very delayed flowering time. In particular, a certain
variability was seen and described for the size and shape of pods and seeds. Two types of Badda
are cultivated, differentiated by the secondary seed colour: the “white Badda” and the “black
Badda”. Both have ivory has a primary seed coat colour, but the “white Badda” has a brownish spot
on the hilum, whereas the “black Badda” shows a black spot. In addition, the secondary colour of
the seed coat of the “black Badda” showed two different pigmentations: violet and black, that
suggested a genetic differentiation into different sub-populations. Finally, the “black Badda”
resulted less susceptible to viral infections than the “white” one.
At the molecular level, three accessions of Badda bean (two ‘white’ and one ‘black’) have
been compared with control varieties, including one accessions of ‘Fagiolo del Purgatorio’ from
Gradoli (VT), seven landraces of the Borlotto type collected in the Marche region and the cultivars
Bat, Jalo, Clio and Big Borlotto. The analyses were carried out using 12 Inter Simple Sequence
Repeats (ISSR) primers yielding a total of 140 bands. Although no specific band for the Badda
landrace were detected, two amplicons were found only in the accessions of Badda and in
Monachello, a bicol-seeded type from the Marche region, morphologically similar to the “black
Badda”. The dendrogram obtained from the genetic distances based on ISSRs indicated that the
Badda type belongs to the Andean gene pool and that it is distinguishable from the tested controls
being grouped into a separate cluster. Within the Badda type, the ‘white’ accessions were not
separated from the ‘black’ one
Bionics-based surgical training using 3D printed photopolymers and smart devices
Additive manufacturing technologies support the realization of surgical training devices using, typically, photopolymers-based materials. Unfortunately, the material jetting family, able to print a large range of soft and hard polymers, requires expensive machines and materials, which are not always available. On the other hand, vat polymerization fails in the resolution/volume ratio and in the mechanical properties reconstruction. Stereolithographic 3D printers, mostly used in dental surgery, make possible to realize cheap and sustainable models for training activity using only one material, reducing the possibility to obtain different mechanical characteristics. Moreover, the printed objects have to be treated (i.e. curing post-processing) in order to obtain the required performances, that could be preserved for long term storing. The aim of the proposed approach is to assure the surgeons' skills improvement through bionic-based surgical 3D printed models and smart devices, able to reproduce the same perception of a real surgical activity. We demonstrated how it is possible develop smart devices capable to take into account the same characteristics of different materials (i.e. bone and spongy bone) even if stored for a long time
Cardiovascular Effects of Whole-Body Cryotherapy in Non-professional Athletes
Objectives: The study aimed to investigate changes in heart rate, blood pressure, respiratory rate, oxygen saturation, and body temperature in non-professional trained runners during whole body cryotherapy (WBC).
Methods: Ten middle-distance runners received 3 once-a-day sessions of WBC. Subjects underwent BP measurements and ECG recorded before and immediately after the daily WBC session. During WBC we recorded a single lead trace (D1) for heart rhythm control. In addition, the 5 vital signs Blood pressure, heart rate, respiratory rate, oxygen saturation, and body temperature were monitored before, during, and after all WBC session.
Results: We did not report significant changes in ECG main intervals (PR, QT, and QTc). Mean heart rate changed from 50.98 ± 4.43 bpm (before) to 56.83 ± 4.26 bpm after WBC session (p < 0.05). The mean systolic blood pressure did not change significantly during and after WBC [b baseline: 118 ± 5 mmHg, changed to 120 ± 3 mmHg during WBC, and to 121 ± 2 mmHg after session (p < 0.05 vs. baseline)]. Mean respiratory rate did not change during WBC as well as oxygen saturations (98 vs. 99%). Body temperature was slightly increased after WBC, however it remains within physiological values
Conclusion: In non-professional athletes WBC did not affect cardiovascular response and can be safely used. However, further studies are required to confirm these promising results of safety in elderly non-athlete subjects
Locality hypothesis and the speed of light
The locality hypothesis is generally considered necessary for the study of
the kinematics of non-inertial systems in special relativity. In this paper we
discuss this hypothesis, showing the necessity of an improvement, in order to
get a more clear understanding of the various concepts involved, like
coordinate velocity and standard velocity of light. Concrete examples are
shown, where these concepts are discussed.Comment: 23 page
Molecular Pathogenesis of Myelodysplastic Syndromes
Myelodysplastic syndromes (MDS) are a group of clonal hematologic disorders characterized by inefficient hematopoiesis, hypercellular bone marrow, dysplasia of blood cells and cytopenias. Most patients are diagnosed in their late 60s to early 70s. MDS is a risk factor for the development of acute myeloid leukemia which can occur in 10-15% of patients with MDS. A variety of pathophysiologic mechanisms contributes to the genesis and persistence of MDS including immunologic, epigenetic, cytogenetic and genetic factors. The only potential curative option for MDS is hematopoietic cell transplantation which is suitable for only a few patients. Currently approved therapeutic options for MDS, including lenalidomide, decitabine, and 5-azacytidine, are targeted to improve transfusion requirements and quality of life. Moreover, 5-azacytidine has also been demonstrated to improve survival in some patients with higher risk MDS. New ways to predict which patients will better gain benefit from currently available therapeutic agents are the primary challenges in MDS. In the last 10 years, chromosome scanning and high throughput technologies (single nucleotide polymorphism array genotyping, comparative genomic hybridization, and whole genome/ exome sequencing) have tremendously increased our knowledge of MDS pathogenesis. Indeed, the molecular heterogeneity of MDS supports the idea of different therapeutic approaches which will take into account the diverse morphologic and clinical presentations of MDS patients rather than a restricted therapeutic strategy. This review will summarize the molecular abnormalities in key relevant components of the biology and pathogenesis of MDS and will provide an update on the clinical impact and therapeutic response in MDS patients
SIRT1 activity in peripheral blood mononuclear cells correlates with altered lung function in patients with chronic obstructive pulmonary disease
Background. Oxidative stress is a recognized pathogenic mechanism in chronic obstructive pulmonary disease (COPD). Expression of the NAD+-dependent deacetylase Sirtuin 1 (SIRT1), an antiaging molecule with a key role in oxidative stress response, has been described as decreased in the lung of COPD patients. No studies so far investigated whether systemic SIRT1 activity was associated to decreased lung function in this disease. Methods. We measured SIRT1 protein expression and activity in peripheral blood mononuclear cells (PBMCs) and total oxidative status (TOS), total antioxidant capacity (TEAC), and oxidative stress index (TOS/TEAC) in the plasma of 25 COPD patients, 20 healthy nonsmokers (HnS), and 20 healthy smokers (HS). Results. The activity of SIRT1 was significantly lower in COPD patients compared to both control groups while protein expression decreased progressively (HnS > HS > COPD). TOS levels were significantly lower in HnS than in smoke-associated subjects (COPD and HS), while TEAC levels were progressively lower according (HnS > HS > COPD). In COPD patients, SIRT1 activity, but not protein levels, correlated significantly with both lung function parameters (FEV1/FVC and FEV1) and TEAC. Conclusions. These findings suggest loss of SIRT1-driven antioxidant activity as relevant in COPD pathogenesis and identify SIRT1 activity as a potential convenient biomarker for identification of mild/moderate, stable COPD
- …