1,648 research outputs found
The Italian version of the Thinking About Life Experiences Questionnaire and its relationship with gender, age, and life events on Facebook
The present study provided a cross-cultural validation of the Thinking About Life Experiences Scale-revised (TALE-R) in an Italian sample of Facebook users (n = 492; female = 378; male = 114; mean age 26.1) to test for replication and universality of the TALE-R three-factor model. Furthermore, it explored the interrelations among gender, age, the scores at the TALE-R and the frequency of posting textual/visual information about individuals' life events on Facebook. Results at exploratory and confirmatory factor analysis gave empirical support to both of a tripartite model for the functions of autobiographical memory (i.e., directive-behavior, social-bonding, and self-continuity) and measurement invariance of this three-factor model across gender and age. Further results at linear correlation and regression analyses showed that directive-behavior and self-continuity functions of autobiographical memory are significantly related to the ways people use Facebook for personal documentation. Age differences more than gender influence this association. Discussion and conclusion reported both theoretical and empirical implications of the findings of the study
Flux tubes in the SU(3) vacuum
We analyze the distribution of the chromoelectric field generated by a static
quark-antiquark pair in the SU(3) vacuum. We find that the transverse profile
of the flux tube resembles the dual version of the Abrikosov vortex field
distribution and give an estimate of the London penetration length in the
confined vacuum.Comment: 7 pages, 3 figures, poster contribution to the XXIX International
Symposium on Lattice Field Theory, LATTICE 201
Chromo-field flux sheets as confining gauge field configurations in the SU(N) Euclidean Yang-Mills theory in the Landau gauge
For the four-dimensional SU(N) Euclidean Yang-Mills theory in the Landau
gauge, we present two sets of gauge field configurations that satisfy the
Euclidean equations of motion. These configurations generate four-dimensional
chromo-field flux sheets whose spatial cross sections are three-dimensional
chromo-field flux tubes. In lattice simulations, they may be detected as center
vortices. The first set of gauge field configurations generates chromo-electric
flux tubes that should contribute to a chromo-electric flux tube between two
static color charges. The string tension for two static color charges in
representation r then naturally satisfies the Casimir scaling. Applying a gauge
transformation to this set of gauge field configurations, we can transform them
into those in the maximal Abelian gauge. These transformed configurations
generate chromo-electric flux tubes that should contribute to those observed
between two static quarks in lattice simulations performed in the maximal
Abelian gauge. The second set of gauge field configurations generates
chromo-magnetic flux tubes. When rotated in a plane that includes the
temporal-axis and is perpendicular to the flux tube axis, the rotated gauge
field configuration generates a chromo-electric flux tube and should contribute
to the chromo-electric flux tubes observed in lattice simulations in the Landau
gauge. We also argue that when regulated on a lattice, any of the flux sheet
gauge field configuration with a finite flux sheet thickness is located on the
Gribov horizon in the infinite lattice volume limit. We thus suggest that these
sets of gauge field configurations contribute significantly to the low energy
properties of QCD, particularly the quark confinement.Comment: 31 pages. The version to appear in Physical Review
p38(MAPK)/p53 signalling axis mediates neuronal apoptosis in response to tetrahydrobiopterin-induced oxidative stress and glucose uptake inhibition: implication for neurodegeneration.
BH4 (tetrahydrobiopterin) induces neuronal demise via production of ROS (reactive oxygen species). In the present study we investigated the mechanisms of its toxicity and the redox signalling events responsible for the apoptotic commitment in SH-SY5Y neuroblastoma cells and in mouse primary cortical neurons. We identified in p38(MAPK)/p53 a BH4-responsive pro-apoptotic signalling axis, as demonstrated by the recovery of neuronal viability achieved by gene silencing or pharmacological inhibition of both p38(MAPK) and p53. BH4-induced oxidative stress was characterized by a decrease in the GSH/GSSG ratio, an increase in protein carbonylation and DNA damage. BH4 toxicity and the redox-activated apoptotic pathway were counteracted by the H2O2-scavengers catalase and N-acetylcysteine and enhanced by the GSH neo-synthesis inhibitor BSO (buthionine sulfoximine). We also demonstrated that BH4 impairs glucose uptake and utilization, which was prevented by catalase administration. This effect contributes to the neuronal demise, exacerbating BH4-induced nuclear damage and the activation of the pro-apoptotic p38(MAPK)/p53 axis. Inhibition of glucose uptake was also observed upon treatment with 6-hydroxydopamine, another redox-cycling molecule, suggesting a common mechanism of action for auto-oxidizable neurotoxins
Rat pial microvascular responses to melatonin during bilateral common carotid artery occlusion and reperfusion
The present study assessed the in vivo rat pial microvascular responses induced by melatonin during brain hypoperfusion and reperfusion (RE) injury. Pial microcirculation of male Wistar rats was visualized by fluorescence microscopy through a closed cranial window. Hypoperfusion was induced by bilateral common carotid artery occlusion (BCCAO, 30 min); thereafter, pial microcirculation was observed for 60 min. Arteriolar diameter, permeability increase, leukocyte adhesion to venular walls, perfused capillary length (PCL), and capillary red blood cell velocity (V(RBC) ) were investigated by computerized methods. Melatonin (0.5, 1, 2 mg/kg b.w.) was intravenously administered 10 min before BCCAO and at the beginning of RE. Pial arterioles were classified in five orders according to diameter, length, and branchings. In control group, BCCAO caused decrease in order 2 arteriole diameter (by 17.5 ± 3.0% of baseline) that was reduced by 11.8 ± 1.2% of baseline at the end of RE, accompanied by marked leakage and leukocyte adhesion. PCL and capillary V(RBC) decreased. At the end of BCCAO, melatonin highest dosage caused order 2 arteriole diameter reduction by 4.6 ± 2.0% of baseline. At RE, melatonin at the lower dosages caused different arteriolar responses. The highest dosage caused dilation in order 2 arteriole by 8.0 ± 1.5% of baseline, preventing leakage and leukocyte adhesion, while PCL and V(RBC) increased. Luzindole (4 mg/kg b.w.) prior to melatonin caused order 2 arteriole constriction by 12.0 ± 1.5% of baseline at RE, while leakage, leukocyte adhesion, PCL and V(RBC) were not affected. Prazosin (1 mg/kg b.w.) prior to melatonin did not significantly change melatonin's effects. In conclusion, melatonin caused different responses during hypoperfusion and RE, modulating pial arteriolar tone likely by MT1 and MT2 melatonin receptors while preventing blood-brain barrier changes through its free radical scavenging action
Under the ROSâŠthiol network is the principal suspect for autophagy commitment.
Low molecular weight and protein sulphydryls undergo reactive oxygen species (ROS)-mediated oxidation. However, in contrast to the irreversible damages that oxidative conditions yield on biomolecules, the oxidation of reactive cysteines frequently results in reversible modifications, which represent the prototype of the molecular mechanisms underlying redox signaling. Many proteins involved in a wide range of cellular processes have been classified as âredoxsensitive,â thereby modulating their function/activity dependent on the redox state of their critical thiols. Growing evidence from the past few years supports the idea that ROS production also correlates with the occurrence of autophagy. Nonetheless, the cysteine protease Atg4 remains the sole example of a protein whose redox regulation has been completely characterized and demonstrated to be necessary for the progression of autophagy. The principal aim of this commentary is to draw attention to the remarkable number of proteins that can fit the double role of: (i) being involved in autophagy, especially in autophagosome formation and (ii) sensing alterations of the cellular redox state by means of reactive cysteine residues. We will also attempt to provide a hypothetical model to explain the possible functional role of thiols in the occurrence of autophagy and outline a network of redox reactions likely concurring to allow the correct initiation and completion of autophagosomes
Carcinoma cells activate AMP-activated protein kinase-dependent autophagy as survival response to kaempferol-mediated energetic impairment.
Kaempferol, a dietary cancer chemopreventive polyphenol, has been reported to trigger apoptosis in several tumor histotypes, but the mechanism underlying this phenomenon is not fully understood. Here, we demonstrate that in HeLa cells, kaempferol induces energetic failure due to inhibition of both glucose uptake and Complex I of the mitochondrial respiratory chain. As adaptive response, cells activate autophagy, the occurrence of which was established cytofluorometrically, upon acridine orange staining, and immunochemically, by following the increase of the autolysosome-associated form of the microtubule-associated protein light chain 3 (LC3-II). Autophagy is an early and reversible process occurring as survival mechanisms against apoptosis. Indeed, chemical inhibition of autophagy, by incubations with monensin, wortmannin, 3-methyladenine, or by silencing Atg5, significantly increases the extent of apoptosis, which takes place via the mitochondrial pathway, and shortens the time in which the apoptotic markers are detectable. We also demonstrate that autophagy depends on the early activation of the AMP-activated protein kinase (AMPK)/mTOR-mediated pathway. The overexpression of dominant negative AMPK results in a decrease of autophagic cells, a decrement of LC3-II levels, and a significant increase of apoptosis. Experiments performed with another carcinoma cell line yielded the same results, suggesting for kaempferol a unique mechanism of action
Do mental health and vitality mediate the relationship between perceived control over time and fear of COVID-19? A survey in an Italian sample
Several studies evidenced increased elevated symptomatology levels in anxiety, general stress, depression, and post-traumatic stress related to COVID-19. Real difficulties in the effective control of time that could be responsible for mental health issues and loss of vitality were also reported. Prior literature highlighted how perceived control over time significantly modulates anxiety disorders and promotes psychological well-being. To verify the hypothesis that perceived control over time predicts fear of COVID-19 and mental health and vitality mediate this relationship, we performed an online survey on a sample of 301 subjects (female = 68%; Mage = 22.12, SD = 6.29; age range = 18â57 years), testing a parallel mediation model using PROCESS macro (model 4). All participants responded to self-report measures of perceived control over time, COVID-19 fear, mental health, and vitality subscales of the Short-Form-36 Health Survey. Results corroborate the hypotheses of direct relationships between all the study variables and partially validate the mediationâs indirect effect. Indeed, mental health (a1b1 = â0.06; CI: LL = â0.11; UL = â0.01; p < 0.001) rather than vitality (a2b2 = â0.06; CI: LL = â0.09; UL = 0.03; n.s.) emerges as a significant mediator between perceived control over time and fear of COVID-19. Practical implications of the study about treatment programs based on perceived control over time and emotional coping to prevent fear and anxiety toward the COVID-19 pandemic are discussed
Volcanic Risk System (SRV): ASI Pilot Project to Support The Monitoring of Volcanic Risk In Italy by Means of EO Data
The ASI-SRV(Sistema Rischio Vulcanico) project
started at the beginning of the 2007 is funded by the Italian
Space Agency (ASI) in the frame of the National Space Plan
2003-2005 under the Earth Observations section for natural
risks management. Coordinated by the Istituto Nazionale di
Geofisica e Vulcanologia (INGV), which is responsible at national
level for the volcanic monitoring, the project has as main
objective to develop a pre-operative system based on EO data
and ground measurements integration to support the volcanic
risk monitoring of the Italian Civil Protection Department. The
project philosophy is to implement specific modules which allow
to process, store and visualize through Web GIS tools EO derived
parameters considering three activity phases: 1) knowledge and
prevention; 2) crisis; 3) post crisis. In order to combine
effectively the EO data and the ground networks measurements
the system will implement a multi-parametric analysis tool,
which represents and unique tool to analyze contemporaneously
a large data set of data in ânear real timeâ. The SRV project will
be tested his operational capabilities on three Italian Volcanoes:
Etna,Vesuvio and Campi Flegrei
Does attentional style moderate the relationship between time perspective and social network addiction? A crossâsectional study on a sample of social networking sites users
The present study investigates the role of attentional style as a moderator variable between temporal perspective and social network addiction, since little is known about usersâ cognitive variables involved in this kind of addictive behavior. To achieve this goal, a sample of 186 volunteers and anonymous social networking sites users (M = 34%; F = 66%; Mage = 22.54 years; SD = 3.94; range: 18 Ă· 45 years) participated in a crossâsectional study. All participants filled out self-report instruments measuring temporal perspective, internal vs. external attentional style, and social network addiction. The results align with the previous literature and show that present fatalistic and past negative time orientations are associated with social network addiction, whereas the future is a negative precursor. Moreover, a fourâstep hierarchical regression analysis showed that internal attentional style is a significant moderator of the relationship between high levels of temporal perspective and a high level of social network addiction. This result suggests that social networkâaddicted users are oriented toward internal stimuli such as their intrusive thoughts or feelings and that social network addiction is similar to obsessive compulsive disorders, depression, or anxiety. Despite its limitations, the present study could contribute to the efforts of clinicians, psychiatrists, psychologists, teachers, and all those who seek to combat social network addiction in developing treatment programs to reduce its harmful effects
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