Nicotine addiction : a review

Nicotine, the major psychoactive compound in tobacco, acts as a potent addictive drug in humans. The addictive nature of nicotine leads to more than 6 million deaths a year. Evidence indicates that nicotine and other drugs of abuse act on central dopaminergic pathways and modulate their neurophysiological mechanisms. Nicotine stimulates dopaminergic pathways and the prefrontal cortex (PFC), inducing enhanced reward perception and increased cognitive function, respectively. These findings are consistent with the fact that nicotine binds to different subtypes of nicotinic acetylcholine receptors present on the neurons found in the PFC and ventral tegmental area of the midbrain. The latter, being the area most involved in addictive behaviour, projects on the limbic system, particularly the nucleus accumbens, and receives afferents from the prefrontal cortex and brainstem. Although dopaminergic pathways and nicotinic acetylcholine receptors are the protagonists of nicotine addiction, several minor pathways and their constituent receptors have been indicated as being either directly or indirectly affected by nicotine. These include serotonergic pathways and central cannabinoid receptors. Despite the scarcity of approved drugs and partial efficacy of approved treatment, insight into nicotine neurophysiological modulation led to better appreciation of nicotine-seeking behaviour and subsequent improved design of pharmacological and behavioural approaches to smoking cessation. Tobacco is the single most preventable cause of death in the world today. Better understanding of the neurobiological mechanisms underlying nicotine addiction will ultimately lead to more effective treatments of both nicotine dependence and nicotine rewarding effects.peer-reviewe

Aggregate worker reallocation and occupational mobility in the United States: 1971-2000

We investigate the evolution and the sources of aggregate employment reallocation in the United States in the 1971-2000 March files of the Current Population Survey. We focus on the annual flows of male workers across occupations at the Census 3-digit level, the finest disaggregation at which a moving worker changes career and relocates to an observationally different technology. We find that the total reallocation of employment across occupations has been strongly procyclical and sharply declining until the early 1990s, before remaining relatively constant in the last decade. To reveal the sources of these patterns, while correcting for possible worker selection into employment, we construct a synthetic panel based on birth cohorts, and estimate various models of worker occupational mobility. We obtain five main results. The cross-occupation dispersion in labor demand, as measured by an index of net employment reallocation, has a strong association with total worker mobility. The demographic composition of employment, more specifically the increasing average age and college attainment level, explains some of the vanishing size and procyclicality of worker flows. High unemployment weakens the effects of individual worker characteristics on their occupational mobility. Worker mobility has significant residual persistence over time, as predicted by job-matching theory. Finally, we detect important unobserved cohort-specific effects; in particular, later cohorts have increasingly low unexplained occupational mobility, which contributes considerably to the downward trend in total employment reallocation over the last three decades.

Occupational Mobility and the Business Cycle

Do workers sort more randomly across different job types when jobs are harder to find? To answer this question, we study the mobility of male workers among three-digit occupations in the matched files of the monthly Current Population Survey over the 1979-2004 period. We clean individual occupational transitions using the algorithm proposed by Moscarini and Thomsson (2008). We then construct a synthetic panel comprising annual birth cohorts, and we examine the respective roles of three potential determinants of career mobility: individual ex ante worker characteristics, both observable and unobservable, labor market prospects, and ex post job matching. We provide strong evidence that high unemployment somewhat offsets the role of individual worker considerations in the choice of changing career. Occupational mobility declines with age, family commitments and education, but when unemployment is high these negative effects are weaker, and reversed for college education. The cross-sectional dispersion of the monthly series of residuals is strongly countercyclical. As predicted by Moscarini (2001)’s frictional Roy model, the sorting of workers across occupations is noisier when unemployment is high. As predicted by job-matching theory, worker mobility has significant residual persistence over time. Finally, younger cohorts, among those in the sample for most of their working lives, exhibit increasingly low unexplained career mobility.occupational mobility, business cycle, synthetic cohorts

Occupational mobility and the business cycle

Do workers sort more randomly across different job types when jobs are harder to find? To answer this question, we study the mobility of male workers among three-digit occupations in the matched files of the monthly Current Population Survey over the 1979-2004 period. We clean individual occupational transitions using the algorithm proposed by Moscarini and Thomsson (2008). We then construct a synthetic panel comprising annual birth cohorts, and we examine the respective roles of three potential determinants of career mobility: individual ex ante worker characteristics, both observable and unobservable, labor market prospects, and ex post job matching. We provide strong evidence that high unemployment somewhat offsets the role of individual worker considerations in the choice of changing career. Occupational mobility declines with age, family commitments and education, but when unemployment is high these negative effects are weaker, and reversed for college education. The cross-sectional dispersion of the monthly series of residuals is strongly countercyclical. As predicted by Moscarini (2001)'s frictional Roy model, the sorting of workers across occupations is noisier when unemployment is high. As predicted by job-matching theory, worker mobility has significant residual persistence over time. Finally, younger cohorts, among those in the sample for most of their working lives, exhibit increasingly low unexplained career mobilit

GaN and SiC Device Characterization by a Dedicated Embedded Measurement System

This work proposes a comparison among GaN and SiC device main parameters measured with a dedicated and low-cost embedded system, employing an STM32 microcontroller designed to the purpose. The system has the advantage to avoid the use of expensive laboratory measurement equipment to test the devices, allowing to obtain their behavior in operating conditions. The following KPIs (Key Performance Indicators) are measured and critically compared: threshold voltage, on-resistance and input capacitance. All the measurements are carried out in a short time interval and on a wide range of switching frequencies, ranging from 10 kHz to 1 MHz. This investigation is focused on the deviation of the figures of merit when the switching frequency changes, since it is crucial for wide-bandgap devices. The devised, low-cost, microcontroller unit allows high flexibility and system portability, while the employed equivalent-time sampling technique overcomes some issues related to the need of high sampling frequency. It allows good performances with common microcontroller embedded AD converters. To validate the proposed system, the obtained results have been compared with the time-domain waveforms acquired with a traditional laboratory oscilloscope and a study of the system’s measurement errors has been carried out. Results show that GaN devices achieve a higher efficiency with respect to SiC devices in the considered range of switching frequencies. The on-resistance exhibited by GaN devices shows, as expected, an increase with frequency, which happens to switching losses, too. On the other hand, GaN devices are more sensitive to parasitic effects and the high dV/dt, due to the reduced switching times, can excite unwanted ringing phenomena

Occupational Mobility and the Business Cycle

Do workers sort more randomly across different job types when jobs are harder to find? To answer this question, we study the mobility of male workers among three-digit occupations in the matched files of the monthly Current Population Survey over the 1979-2004 period. We clean individual occupational transitions using the algorithm proposed by Moscarini and Thomsson (2008). We then construct a synthetic panel comprising annual birth cohorts, and we examine the respective roles of three potential determinants of career mobility: individual ex ante worker characteristics, both observable and unobservable, labor market prospects, and ex post job matching. We provide strong evidence that high unemployment somewhat offsets the role of individual worker considerations in the choice of changing career. Occupational mobility declines with age, family commitments and education, but when unemployment is high these negative effects are weaker, and reversed for college education. The cross-sectional dispersion of the monthly series of residuals is strongly countercyclical. As predicted by Moscarini (2001)'s frictional Roy model, the sorting of workers across occupations is noisier when unemployment is high. As predicted by job-matching theory, worker mobility has significant residual persistence over time. Finally, younger cohorts, among those in the sample for most of their working lives, exhibit increasingly low unexplained career mobility.

A safe transoral surgical approach to parapharyngeal tumor arising from deep lobe of parotid gland

The management of parapharyngeal tumor is surgical, but the approach remains a challenge. Attention should be paid to avoidance intra-operative bleeding or cranial nerves damage. We report a case of a 67-year-old male complaining of left-ear fullness. A submucosal mass arising from the lateral wall of oropharynx on the left side was observed. Magnetic resonance imaging detected a mass arising from the parotid gland, in particular from the deep lobe, and a fine needle biopsy was compatible with "Warthin tumor." We performed a mini-invasive transoral approach under magnification, previous isolation of homolateral vessels. The decision on which surgical approach to be used is determined by site, size vascularity, and histology of the tumor. A literature review of the main surgical approaches was performed. We performed a combined transoral dissection under magnification with cervicotomic exposure of the neck vascular bundle allowing to dissect the tumor and manage any intra-operative complications

The central role of aquaporins in the pathophysiology of ischemic stroke

Stroke is a complex and devastating neurological condition with limited treatment options. Brain edema is a serious complication of stroke. Early edema formation can significantly contribute to infarct formation and thus represents a promising target. Aquaporin (AQP) water channels contribute to water homeostasis by regulating water transport and are implicated in several disease pathways. At least 7 AQP subtypes have been identified in the rodent brain and the use of transgenic mice has greatly aided our understanding of their functions. AQP4, the most abundant channel in the brain, is up-regulated around the peri-infarct border in transient cerebral ischemia and AQP4 knockout mice demonstrate significantly reduced cerebral edema and improved neurological outcome. In models of vasogenic edema, brain swelling is more pronounced in AQP4-null mice than wild-type providing strong evidence of the dual role of AQP4 in the formation and resolution of both vasogenic and cytotoxic edema. AQP4 is co-localized with inwardly rectifying K+-channels (Kir4.1) and glial K+ uptake is attenuated in AQP4 knockout mice compared to wild-type, indicating some form of functional interaction. AQP4-null mice also exhibit a reduction in calcium signaling, suggesting that this channel may also be involved in triggering pathological downstream signaling events. Associations with the gap junction protein Cx43 possibly recapitulate its role in edema dissipation within the astroglial syncytium. Other roles ascribed to AQP4 include facilitation of astrocyte migration, glial scar formation, modulation of inflammation and signaling functions. Treatment of ischemic cerebral edema is based on the various mechanisms in which fluid content in different brain compartments can be modified. The identification of modulators and inhibitors of AQP4 offer new therapeutic avenues in the hope of reducing the extent of morbidity and mortality in stroke.peer-reviewe

Effectiveness of mRNA Vaccine Booster against SARS-CoV-2 Infection and COVID-19 in the Adult Population during the First Three Months of the Omicron Wave in Sicily

Background: In Italy, the administration of the COVID-19 vaccine booster dose started on 27 September 2021, supported by clinical trials corroborating its efficacy. Given the paucity of real-world effectiveness data, this study aims to estimate the vaccine effectiveness of the booster dose against SARS-CoV-2 infection, severe disease, and death in the adult Sicilian population. Methods: This retrospective cohort study was carried out from 1 January to 31 March 2022 and included all residents in Sicily aged >= 18 years without previous SARS-CoV-2 infection and with a complete mRNA vaccine primary cycle. The cohort was split into two groups (booster and primary cycle) matched by age, gender, vaccine type, and month of completion of the primary vaccination cycle. Results: 913,382 subjects were observed in the study: 456,690 (50%) were vaccinated with two doses and 456,692 (50%) with three doses. There were 43,299 cases of SARS-CoV-2 among the two-doses vaccinees (9.5%) and 10,262 (2.2%) among the three-doses counterpart. Vaccine effectiveness in the booster cohort was 76.5% and 74.4% against SARS-CoV-2 infection, 85.7% and 79.7% against severe disease, and 84.1% and 73.1% against intubation or death, for BNT162b2 and mRNA-1273, respectively. Conclusions: This study confirmed the remarkable efficacy profile of the SARS-CoV-2 vaccine booster dose against infection, severe disease, and death attributable to the virus. Overall, the results of this study provide important real-world data to support the continued roll-out of the COVID-19 booster dose and have the potential to inform public health policy and guide decisions on vaccination strategies in countries around the world