187 research outputs found
Use of Carbon Nitrides as Photoactive Supports in Single‐Atom Heterogeneous Catalysis for Synthetic Purposes
In recent years, the field of dual photocatalysis has become an increasingly popular tool for the functionalization of organic substrates under mild operative conditions. Single-atom heterogeneous catalysts (SACs), where the metal atoms are stabilized by means of properly structured photoactive supports, are currently one of the frontiers of this research field. To this end, Carbon Nitrides (CNs) have emerged as ideal two-dimensional semiconducting supports, capable of stabilizing single metal sites (for instance: nickel, iron, among other) through nitrogen-rich structures. This Concept highlights the recent advances in the synthesis of carbon nitride-based SACs and their applications in light-driven dual-catalytic processes, also providing forward-looking opportunities within this research area
Activation of Jun N-terminal Kinase/Stress-activated Protein Kinase Pathway by Tumor Necrosis Factor α Leads to Intercellular Adhesion Molecule-1 Expression
Tumor necrosis factor alpha (TNF-alpha) is a cytokine implicated in the pathogenesis of numerous chronic and acute inflammatory conditions. We have previously shown that mouse Sertoli cells respond to TNF-alpha by increasing interleukin-6 production and intercellular adhesion molecule-1 (ICAM-1) expression (1). In this cell type TNF-alpha activates the mitogen-activated protein kinase (MAPK) pathways p42/p44 MAPK, JNK/SAPK, and p38, the last of which is responsible for interleukin-6 production (1). To determine which MAPK signaling pathway is required for TNF-alpha induction of ICAM-1 expression, we have utilized the protein kinase inhibitor dimethylaminopurine, demonstrating that treatment of Sertoli cells with such compound significantly reduced ICAM-1 expression and JNK/SAPK activation. Moreover, dimethylaminopurine treatment increased the expression of MAPK phosphatase-2, providing a possible mechanism of action of this compound. By using agonist antibodies to p55 and to p75 TNF-alpha receptors and both human and mouse TNF-alpha, we demonstrate that both TNF receptors are expressed and that only the p55 receptor is involved in ICAM-1 expression. The p55 receptor activates all of the three pathways, whereas p75 failed to activate any of the MAPKs. Altogether our results demonstrate that TNF-alpha up-regulates ICAM-1 expression through the activation of the JNK/SAPK transduction pathway mediated by the p55 receptor
Lattice-dynamical calculations on some rigid organic molecules
Several physical-chemical properties in crystals formed by "rigid" organic molecules have been calculated by means of different semiempirical atom-atom potential functions. For nine different substances, vibration frequencies, dispersion curves, and "crystallographic" temperature factors have been evaluated, and as an example the density of states for two of them are also reported. Experimental data are in excellent to fair agreement with results obtained by use of "Williams IVa" functions; some of these results can be advantageously used for libration correction of bond lengths that are determined by x-ray or neutron diffraction. Among the examined substances, some anomalies are found for pyrene crystals, which confirm in this case a rather unusual way of packing
Modeling Early Phases of COVID-19 Pandemic in Northern Italy and Its Implication for Outbreak Diffusion
The COVID-19 pandemic has sparked an intense debate about the hidden factors
underlying the dynamics of the outbreak. Several computational models have been
proposed to inform effective social and healthcare strategies. Crucially, the predictive
validity of these models often depends upon incorporating behavioral and social
responses to infection. Among these tools, the analytic framework known as “dynamic
causal modeling” (DCM) has been applied to the COVID-19 pandemic, shedding new
light on the factors underlying the dynamics of the outbreak. We have applied DCM
to data from northern Italian regions, the first areas in Europe to contend with the
outbreak, and analyzed the predictive validity of the model and also its suitability in
highlighting the hidden factors governing the pandemic diffusion. By taking into account
data from the beginning of the pandemic, the model could faithfully predict the dynamics
of outbreak diffusion varying from region to region. The DCM appears to be a reliable tool
to investigate the mechanisms governing the spread of the SARS-CoV-2 to identify the
containment and control strategies that could efficiently be used to counteract further
waves of infection
The Nickel Age in Synthetic Dual Photocatalysis: A Bright Trip Toward Materials Science
Recently, the field of dual photocatalysis has grown rapidly, to become one of the most powerful tools for the functionalization of organic molecules under mild conditions. In particular, the merging of Earth-abundant nickel-based catalytic systems with visible-light-activated photoredox catalysts has allowed the development of a number of unique green synthetic approaches. This goes in the direction of ensuring an effective and sustainable chemical production, while safeguarding human health and environment. Importantly, this relatively new branch of catalysis has inspired an interdisciplinary stream of research that spans from inorganic and organic chemistry to materials science, thus establishing itself as one dominant trend in modern organic synthesis. This Review aims at illustrating the milestones on the timeline evolution of the photocatalytic systems used, with a critical analysis toward novel applications based on the use of photoactive two-dimensional carbon-based nanostructures. Lastly, forward-looking opportunities within this intriguing research field are discussed
Lockdown timing and efficacy in controlling COVID-19 using mobile phone tracking
Background
Italy's severe COVID-19 outbreak was addressed by a lockdown that gradually increased in space, time and intensity. The effectiveness of the lockdown has not been precisely assessed with respect to the intensity of mobility restriction and the time until the outbreak receded.
Methods
We used processed mobile phone tracking data to measure mobility restriction, and related those data to the number of new SARS-CoV-2 positive cases detected on a daily base in the three most affected Italian regions, Lombardy, Veneto and Emilia-Romagna, from February 1 through April 6, 2020, when two subsequent lockdowns with increasing intensity were implemented by the Italian government.
Findings
During the study period, mobility restriction was inversely related to the daily number of newly diagnosed SARS-CoV-2 positive cases only after the second, more effective lockdown, with a peak in the curve of diagnosed cases of infection occurring 14 to 18 days from lockdown in the three regions and 9 to 25 days in the included provinces. An effective reduction in transmission must have occurred nearly immediately after the tighter lockdown, given the lag time of around 10 days from asymptomatic infection to diagnosis. The period from lockdown to peak was shorter in the areas with the highest prevalence of the infection. This effect was seen within slightly more than one week in the most severely affected areas.
Interpretation
It appears that the less rigid lockdown led to an insufficient decrease in mobility to reverse an outbreak such as COVID-19. With a tighter lockdown, mobility decreased enough to bring down transmission promptly below the level needed to sustain the epidemic.
Funding
No funding sources have been used for this work
Alcohol Intake and Blood Pressure Levels: A Dose-Response Meta-Analysis of Nonexperimental Cohort Studies
Background: Alcohol consumption may increase blood pressure but the details of the relationship are incomplete, particularly for the association at low levels of alcohol consumption, and no meta-analyses are available for nonexperimental cohort studies. Methods: We performed a systematic search of longitudinal studies in healthy adults that reported on the association between alcohol intake and blood pressure. Our end points were the mean differences over time of systolic (SBP) and diastolic blood pressure (DBP), plotted according to baseline alcohol intake, by using a dose-response 1-stage meta-analytic methodology. Results: Seven studies, with 19 548 participants and a median follow-up of 5.3 years (range, 4-12 years), were included in the analysis. We observed a substantially linear positive association between baseline alcohol intake and changes over time in SBP and DBP, with no suggestion of an exposure-effect threshold. Overall, average SBP was 1.25 and 4.90 mm Hg higher for 12 or 48 grams of daily alcohol consumption, compared with no consumption. The corresponding differences for DBP were 1.14 and 3.10 mm Hg. Subgroup analyses by sex showed an almost linear association between baseline alcohol intake and SBP changes in both men and women, and for DBP in men while in women we identified an inverted U-shaped association. Alcohol consumption was positively associated with blood pressure changes in both Asians and North Americans, apart from DBP in the latter group. Conclusions: Our results suggest the association between alcohol consumption and SBP is direct and linear with no evidence of a threshold for the association, while for DBP the association is modified by sex and geographic location
Atrial Fibrillation and the Risk of Early‐Onset Dementia: A Systematic Review and Meta‐Analysis
BACKGROUNDRecent studies have identified an increased risk of dementia in patients with atrial fibrillation (AF). However, both AF and dementia usually manifest late in life. Few studies have investigated this association in adults with early‐onset dementia. The aim of this study was to investigate the relationship between AF and early‐onset dementia.
METHODS AND RESULTSWe searched the PubMed/MEDLINE, Embase, and Scopus databases through April 15, 2022, for studies reporting on the association between AF and dementia in adults aged <70 years, without language restrictions. Two reviewers independently performed the study selection, assessed the risk of bias, and extracted the study data. We performed a meta‐analysis of early‐onset dementia risk according to occurrence of AF using a random‐effects model. We retrieved and screened 1006 potentially eligible studies. We examined the full text of 33 studies and selected the 6 studies that met our inclusion criteria. The pooled analysis of their results showed an increased risk of developing dementia in individuals with AF, with a summary relative risk of 1.50 (95% CI, 1.00–2.26) in patients aged <70 years, and 1.06 (95% CI, 0.55–2.06) in those aged <65 years.
CONCLUSIONSIn this systematic review and meta‐analysis, AF was a risk factor for dementia in adults aged <70 years, with an indication of a slight and statistically imprecise excess risk already at ages <65 years. Further research is needed to assess which characteristics of the arrhythmia and which mechanisms play a role in this relationship
Effectiveness of an Active and Continuous Surveillance Program for Intensive Care Units Infections Based on the EPIC III (Extended Prevalence of Infection in Intensive Care) Approach
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