38 research outputs found

    Can a single low-intensity premature stimulus induce ventricular arrhythmias in the normal heart?

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    Previously, we observed that a single low-intensity premature ventricular stimulation could occasionally induce spontaneous ectopic beats in normal rat hearts. Possible hypothesis for the arrhythmia is that a premature beat can encounter a zone of conduction block to initiate reentry. However, enhanced dispersion of repolarization, a necessary condition for initiation of reentry, is unlikely to be present in normal myocardium. Thus, the main objective of the present study was to perform detailed pace mapping measurements in normal ventricular myocardium with a view to identify pacing sites and critical coupling intervals which could induce spontaneous ectopic beats and to characterize the reentrant circuits

    The loess deposits of Buca Dei Corvi section (Central Italy): Revisited

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    Loess deposits have been described in the past for the upper section of Buca Dei Corvi succession (Central Italy). In this paper the depositswere re-analysed to clarify the depositional environment and to attempt a paleoclimate reconstruction. Two radiocarbon dates on pedogenic carbonate constrain the ages to the Late Glacial, and are consistent with previous OSL dating of the top of the succession. The non-marine mollusc assemblage shows typical character of cold and dry climatic conditions, testified by strong oligotypical composition. Mineralogy and geochemistry of the sediments indicate the abundant presence of exotic quartz mineral which can be explained only by wind transport. Probably,wind transportwas also responsible of deposition of carbonatewhich then dissolved and re-precipitated producing pedogenic concretions. Stable isotopes (13C/12C and 18O/16O ratios) of the concretions are consistent with a climate drier than present conditions, with an environment characterized by sparse vegetation

    The COVID-19 Pandemic and Its Impact on Families' Mental Health: The Role Played by Parenting Stress, Parents' Past Trauma, and Resilience

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    International research has evidenced the psychological impact of the COVID-19 pandemic on families, and the key role played by parenting stress levels. Although significant associations with parents' past trauma and resilience have been shown, this study aimed to explore their complex interplay on the relationship between parents' peritraumatic distress due to COVID-19, parenting stress, and children's psychopathological difficulties. We recruited 353 parents with children aged two to 16 years via an online survey during the Italian second wave of COVID-19. Parents' peritraumatic distress due to COVID-19, parenting stress, past trauma and resilience, and children's psychological difficulties were assessed through self-report and report-form questionnaires. Parents' past traumas significantly predicted peritraumatic distress due to COVID-19 and children's psychological difficulties. The relationship between past traumas and children's psychological difficulties was serial mediated by parents' peritraumatic distress and parenting stress. Direct and total effects of parent's resilience on parent's peritraumatic distress were not significant, but there were significant indirect effects via parenting stress and via parents' peritraumatic distress and parenting stress, indicating inconsistent mediation. This study evidenced the key risk and protective role played by, respectively, parents' past traumas exposure and resilience on the relationship between parents' psychological difficulties due to COVID-19, parenting stress, and children's psychological difficulties, with important clinical implications

    SRTP assessment of passenger ships: a simulation tool

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    Recent years have seen increasing attention being paid towards the problems related to safety and security onboard ships. As a result, the International Maritime Organization has issued several new Regulations regarding ships\u2019 systems that must be considered during the vessel design phases. In particular, one of the most important approaches introduced by this set of rules consists of the Safe Return to Port (SRtP) concept: basically, the ship itself represents its best lifeboat. Essential systems on-board passenger ships shall be designed in order to both guarantee their functionality and allow the return of the ship to the nearest port during specific emergency situations. Consequently, it is evident that designers should pay great attention to these systems since the early stages of the project. In this framework, proper IT design tools able to simulate systems functionality can represent a valuable aid to ensure compliance with the SRtP requirements. In this paper, the basic principles of SRtP Regulations are thoroughly presented. Furthermore, an IT tool, specifically implemented to address the suggested design approach for ship systems, is analyzed

    Trimethylsilyl trifluoromethanesulfonate-promoted cycloaddition of nitrones with silyl enol ethers: synthesis and reactivity of 5-siloxyisoxazolidines

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    In the presence of trimethylsilyl trifluoromethanesulfonate (TMSOTf), the reaction of nitrones with silyl enol ethers affords 5-siloxyisoxazolidines under mild conditions, in good to excellent yields. 5-Siloxyisoxazolidines can undergo chemoselective reductions to Manoich bases or N-hydroxy-1,3-amino alcohols, and, in the presence of TMSOTf, react with silylated carbon nucleophiles at the acetalic C-5 carbon to give, for example, 5-allyl- and 5-cyano-isoxazolidines

    Different patterns of respiration in rat lines selectively bred for high or low anxiety

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    In humans, there is unequivocal evidence of an association between anxiety states and altered respiratory function. Despite this, the link between anxiety and respiration has been poorly evaluated in experimental animals. The primary objective of the present study was to investigate the hypothesis that genetic lines of rats that differ largely in their anxiety level would display matching alterations in respiration. To reach this goal, respiration was recorded in high-anxiety behavior (HAB, n = 10) and low-anxiety behavior (LAB, n = 10) male rats using whole-body plethysmography. In resting state, respiratory rate was higher in HABs (85±2 cycles per minute, cpm) than LABs (67±2 cpm, p<0.05). During initial testing into the plethysmograph and during a restraint test, HAB rats spent less time at high-frequency sniffing compared to LAB rats. In addition, HAB rats did not habituate in terms of respiratory response to repetitive acoustic stressful stimuli. Finally, HAB rats exhibited a larger incidence of sighs during free exploration of the plethysmograph and under stress conditions. We conclude that: i) HAB rats showed respiratory changes (elevated resting respiratory rate, reduced sniffing in novel environment, increased incidence of sighs, and no habituation of the respiratory response to repetitive stimuli) that resemble those observed in anxious and panic patients, and ii) respiratory patterns may represent a promising way for assessing anxiety states in preclinical studies

    The Quality of Mother-Child Feeding Interactions Predicts Psychopathological Symptoms in Offspring and Mothers Seven Years Later: A Longitudinal Study on the General Population.

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    The increased risk of internalizing and externalizing symptoms in children has been observed in the presence of maternal psychopathology. This study aimed to investigate a potential pathway involving the quality of early interactions between mothers and their children. A sample of 150 mother-child dyads underwent assessment when the children were 3 years old and around the age of 10. Video recordings of feeding exchanges between mothers and children were analyzed to evaluate the quality of mother-child interactions. Maternal psychopathology and child internalizing and externalizing symptoms were measured through self-report and report-form measures completed by mothers. The quality of mother-child feeding interactions at three years of age significantly differentiated (p < 0.001), eight years later, between mothers at high and low psychopathological risk and between children exhibiting clinical and subclinical internalizing symptoms. Clinically relevant child symptoms were notably more prevalent when the mother-child interaction quality at three years of age was maladaptive, particularly in the context of concurrent high maternal psychopathological risk. The study findings underscore the importance of focusing on the early quality of mother-child feeding interactions to identify potential situations of maternal and child clinical risk for the development of psychopathological symptoms and to guide preemptive measures and policies

    Vagal withdrawal and susceptibility to cardiac arrhythmias in rats with high trait aggressiveness

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    Personality characteristics, e.g. aggressiveness, have long been associated with an increased risk of cardiac disease. However, the underlying mechanisms remain unclear. In this study we used a rodent model for characterizing cardiac autonomic modulation in rats that differ widely in their level of aggressive behavior. To reach this goal, high-aggressive (HA, n = 10) and non-aggressive (NA, n = 10) rats were selected from a population (n = 121) of adult male Wild-type Groningen rats on the basis of their latency time to attack (ALT, s) a male intruder in a resident-intruder test lasting 600 s. In order to obtain information on their cardiac autonomic modulation, ECG recordings were subsequently obtained via radiotelemetry at rest, during stressful stimuli and under autonomic pharmacological manipulations, and analyzed by means of time- and frequency-domain indexes of heart rate variability. During resting conditions, HA rats (ALT600 s). Exposure to stressful stimuli (i.e. restraint and psychosocial stress) provoked similar tachycardic responses between the two groups. However, under stress conditions HA rats displayed a reduced vagal antagonism and an increased incidence of tachyarrhythmias compared to NA rats. In addition, beta-adrenergic pharmacological stimulation induced a much larger incidence of ventricular tachyarrhythmias in HA rats compared to NA counterparts. These findings are consistent with the view that high levels of aggressive behavior in rats are associated to signs of cardiac autonomic impairment and increased arrhythmogenic susceptibility that may predict vulnerability to cardiac morbidity and mortality
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