4,609 research outputs found
On Redundancy Elimination Tolerant Scheduling Rules
In (Ferrucci, Pacini and Sessa, 1995) an extended form of resolution, called
Reduced SLD resolution (RSLD), is introduced. In essence, an RSLD derivation is
an SLD derivation such that redundancy elimination from resolvents is performed
after each rewriting step. It is intuitive that redundancy elimination may have
positive effects on derivation process. However, undesiderable effects are also
possible. In particular, as shown in this paper, program termination as well as
completeness of loop checking mechanisms via a given selection rule may be
lost. The study of such effects has led us to an analysis of selection rule
basic concepts, so that we have found convenient to move the attention from
rules of atom selection to rules of atom scheduling. A priority mechanism for
atom scheduling is built, where a priority is assigned to each atom in a
resolvent, and primary importance is given to the event of arrival of new atoms
from the body of the applied clause at rewriting time. This new computational
model proves able to address the study of redundancy elimination effects,
giving at the same time interesting insights into general properties of
selection rules. As a matter of fact, a class of scheduling rules, namely the
specialisation independent ones, is defined in the paper by using not trivial
semantic arguments. As a quite surprising result, specialisation independent
scheduling rules turn out to coincide with a class of rules which have an
immediate structural characterisation (named stack-queue rules). Then we prove
that such scheduling rules are tolerant to redundancy elimination, in the sense
that neither program termination nor completeness of equality loop check is
lost passing from SLD to RSLD.Comment: 53 pages, to appear on TPL
Infectious agents in atherosclerotic cardiovascular diseases through oxidative stress
Accumulating evidence demonstrates that vascular oxidative stress is a critical feature of atherosclerotic process, potentially triggered by several infectious agents that are considered as risk co-factors for the atherosclerotic cardiovascular diseases (CVDs). C. pneumoniae has been shown to upregulate multiple enzymatic systems capable of producing reactive oxygen species (ROS) such as NADPH oxidase (NOX) and cyclooxygenase in vascular endothelial cells, NOX and cytochrome c oxidase in macrophages as well as nitric oxide synthase and lipoxygenase in platelets contributing to both early and late stages of atherosclerosis. P. gingivalis seems to be markedly involved in the atherosclerotic process as compared to A. actinomycetemcomitans contributing to LDL oxidation and foam cell formation. Particularly interesting is the evidence describing the NLRP3 inflammasome activation as a new molecular mechanism underlying P. gingivalis-induced oxidative stress and inflammation. Amongst viral agents, immunodeficiency virus-1 and hepatitis C virus seem to have a major role in promoting ROS production, contributing, hence, to the early stages of atherosclerosis including endothelial dysfunction and LDL oxidation. In conclusion, oxidative mechanisms activated by several infectious agents during the atherosclerotic process underlying CVDs are very complex and not well-known, remaining, thus, an attractive target for future research
Pharmacogenetics and Forensic Toxicology: A New Step towards a Multidisciplinary Approach
Pharmacogenetics analyzes the individual behavior of DNA genes after the administration
of a drug. Pharmacogenetic research has been implemented in recent years thanks to the improvement in genome sequencing techniques and molecular genetics. In addition to medical purposes,
pharmacogenetics can constitute an important tool for clarifying the interpretation of toxicological
data in post-mortem examinations, sometimes crucial for determining the cause and modality of
death. The purpose of this systematic literature review is not only to raise awareness among the
forensic community concerning pharmacogenetics, but also to provide a workflow for forensic toxicologists to follow in cases of unknown causes of death related to drug use/abuse. The scientific
community is called on to work hard in order to supply evidence in forensic practice, demonstrating that this investigation could become an essential tool both in civil and forensic contexts. The
following keywords were used for the search engine: (pharmacogenetics) AND (forensic toxicology);
(pharmacogenetics) AND (post-mortem); (pharmacogenetics) AND (forensic science); and (pharmacogenetics) AND (autopsy). A total of 125 articles were collected. Of these, 29 articles were included
in this systematic review. A total of 75% of the included studies were original articles (n = 21) and
25% were case reports (n = 7). A total of 78% (n = 22) of the studies involved deceased people for
whom a complete autopsy was performed, while 22% (n = 6) involved people in good health who
were given a drug with a subsequent pharmacogenetic study. The most studied drugs were opioids
(codeine, morphine, and methadone), followed by antidepressants (tricyclic antidepressants and
venlafaxine). Furthermore, all studies highlighted the importance of a pharmacogenetics study in
drug-related deaths, especially in cases of non-overdose of drugs of abuse. This study highlights the
importance of forensic pharmacogenetics, a field of toxicology still not fully understood, which is of
great help in cases of sudden death, deaths from overdose, deaths after the administration of a drug,
and also in cases of complaint of medical malpractice
New insights into Chlamydiae persistence: an energy metabolism strategy?
Chlamydiaceae is a family of obligate intracellular bacteria generally considered energy parasites. Several studies have suggested that Chlamydiae are capable of independently producing energy and, more importantly, several genes involved in the energy metabolism are up-regulated during the persistent state. Thus, it has been suggested that chlamydial persistence could be a complex and flexible metabolic strategy designed to favor a lengthy survival in the host cell by evading the immune response. In conclusion, more detailed studies on the shift in the chlamydial energy metabolism, from the active to the persistent form, may be helpful in future to determine whether chlamydial persistence observed in vitro does occur in vivo and whether chronic sequelae of chlamydial diseases may be related to the persistence
Risks and critical issues related to the discovery on the market of unauthorized live alien species on the Italian territory: Chinese crab (Eriocheir sinensis)
Eriocheir sinensis, Chinese Crab or Chinese Mitten Crab is a catadromous species belonging to the Varunidae family, native to river and estuarine areas of North and South East China and Korea. At European level, E. sinensis is widespread in the main water basins of Central and Northern Europe and, since 2016, it has been included in the list of invasive species important for the European Union and subjected to confinement and eradication measures which include the prohibition of collection, transit and placing on the market of live specimens (Regulation (EC) N° 1143/2014). The Chinese Crab can represent a significant danger for the local ecosystem and for the native biota as well as contributing to the appearance of hydrogeological instability phenomena resulting from the intense excavation and erosion of the riverbanks. The first finding of 5 kg of live specimens of Eriocheir sinensis was recorded in the official control by the UFS (Functional Simple Unit) veterinary public health and food safety of the ASL Toscana Centro at an ethnic catering establishment. The specimens were subjected to seizure, photographed, identified morphologically, and subjected to euthanasia and destruction in accordance with the European requirements for welfare and management of animal by-products. From the sanitary point of view, the dangers associated with the consumption of this crab are mainly biological and chemical therefore, risk communication is fundamental, not only at the level of the competent authorities in the sector, but also for the food business operators
Evolution of the La(III) ion coordination sphere in ethylammonium nitrate solution upon water addition
A thorough structural study of La(NO3)3 salt solutions in mixtures of the ethylammonium nitrate (EAN) ionic liquid (IL) and water with EAN molar fraction (X EAN) ranging from 0 to 1 has been carried out by means of X-ray absorption spectroscopy (XAS) measurements at the La K-edge and molecular dynamics (MD) simulations. Both the XAS and MD outcomes agree in finding that the composition of the La3+ ion first solvation shell undergoes steadily changes when moving from pure water to pure EAN. Upon increasing of the IL concentration, the La3+ solvation complexes progressively lose water molecules to accommodate more and more nitrate anions, and the ratio between the two ligands continuously changes across the explored composition range. The nitrate ligands coordinate the metal ion only in a monodentate fashion for the lower EAN contents, while the percentage of bidentate nitrates becomes more and more predominant as the EAN concentration increases. When moving from pure water to pure EAN, the La3+ ion coordination passes from a 9-fold tricapped trigonal prismatic geometry to a 12-fold icosahedral one, while a 10-fold coordination with bicapped square antiprism geometry is the dominant species for the mixed compositions. The remarkable flexibility of this solvation complex in accommodating a variable amount of water molecules and nitrate ligands at dependence of the system composition is key for its predominance in all the EAN/water mixtures
Spatiotemporal dynamics of covert versus overt processing of happy, fearful and sad facial expressions
Behavioral and electrophysiological correlates of the influence of task demands on the processing of happy, sad, and fearful expressions were investigated in a within-subjects study that compared a perceptual distraction condition with task-irrelevant faces (e.g., covert emotion task) to an emotion task-relevant categorization condition (e.g., overt emotion task). A state-of-the-art non-parametric mass univariate analysis method was used to address the limitations of previous studies. Behaviorally, participants responded faster to overtly categorized happy faces and were slower and less accurate to categorize sad and fearful faces; there were no behavioral differences in the covert task. Event-related potential (ERP) responses to the emotional expressions included the N170 (140-180 ms), which was enhanced by emotion irrespective of task, with happy and sad expressions eliciting greater amplitudes than neutral expressions. EPN (200-400 ms) amplitude was modulated by task, with greater voltages in the overt condition, and by emotion, however, there was no interaction of emotion and task. ERP activity was modulated by emotion as a function of task only at a late processing stage, which included the LPP (500-800 ms), with fearful and sad faces showing greater amplitude enhancements than happy faces. This study reveals that affective content does not necessarily require attention in the early stages of face processing, supporting recent evidence that the core and extended parts of the face processing system act in parallel, rather than serially. The role of voluntary attention starts at an intermediate stage, and fully modulates the response to emotional content in the final stage of processing
Morphological alterations and stress protein variations in lung biopsies obtained from autopsies of covid-19 subjects
Molecular chaperones, many of which are heat shock proteins, play a role in cell stress response and regulate the immune system in various ways, such as in inflammatory/autoimmune reactions. It would be interesting to study the involvement of these molecules in the damage done to COVID-19-infected lungs. In our study, we performed a histological analysis and an immunomorphological evaluation on lung samples from subjects who succumbed to COVID-19 and subjects who died from other causes. We also assessed Hsp60 and Hsp90 distribution in lung samples to determine their location and post-translational modifications. We found histological alterations that could be considered pathognomonic for COVID-19-related lung disease. Hsp60 and Hsp90 immunopositivity was significantly higher in the COVID-19 group compared to the controls, and immunolocalization was in the plasma membrane of the endothelial cells in COVID-19 subjects. The colocalization ratios for Hsp60/3-nitrotyrosine and Hsp60/acetylate-lisine were significantly increased in the COVID-19 group compared to the control group, similar to the colocalization ratio for Hsp90/acetylate-lisine. The histological and immunohistochemical findings led us to hypothesize that Hsp60 and Hsp90 might have a role in the onset of the thromboembolic phenomena that lead to death in a limited number of subjects affected by COVID-19. Further studies on a larger number of samples obtained from autopsies would allow to confirm these data as well as discover new biomarkers useful in the battle against this disease
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