Nanoparticle-doped electrospun fiber random lasers with spatially extended light modes

Complex assemblies of light-emitting polymer nanofibers with molecular materials exhibiting optical gain can lead to important advance to amorphous photonics and to random laser science and devices. In disordered mats of nanofibers, multiple scattering and waveguiding might interplay to determine localization or spreading of optical modes as well as correlation effects. Here we study electrospun fibers embedding a lasing fluorene-carbazole-fluorene molecule and doped with titania nanoparticles, which exhibit random lasing with sub-nm spectral width and threshold of about 9 mJ cm^-2 for the absorbed excitation fluence. We focus on the spatial and spectral behavior of optical modes in the disordered and non-woven networks, finding evidence for the presence of modes with very large spatial extent, up to the 100 micrometer-scale. These findings suggest emission coupling into integrated nanofiber transmission channels as effective mechanism for enhancing spectral selectivity in random lasers and correlations of light modes in the complex and disordered material.Comment: 22 pages, 6 figure

Diverse regimes of mode intensity correlation in nanofiber random lasers through nanoparticle doping

Random lasers are based on disordered materials with optical gain. These devices can exhibit either intensity or resonant feedback, relying on diffusive or interference behaviour of light, respectively, which leads to either coupling or independent operation of lasing modes. We study for the first time these regimes in complex, solid-state nanostructured materials. The number of lasing modes and their intensity correlation features are found to be tailorable in random lasers made of light-emitting, electrospun polymer fibers upon nanoparticle doping. By material engineering, directional waveguiding along the length of fibers is found to be relevant to enhance mode correlation in both intensity feedback and resonant feedback random lasing. The here reported findings can be used to establish new design rules for tuning the emission of nano-lasers and correlation properties by means of the compositional and morphological properties of complex nanostructured materials.Comment: 30 pages, 10 figure

Unravelling the hidden ancestry of American admixed populations

The movement of people into the Americas has brought different populations into contact, and contemporary American genomes are the product of a range of complex admixture events. Here we apply a haplotype-based ancestry identification approach to a large set of genome-wide SNP data from a variety of American, European and African populations to determine the contributions of different ancestral populations to the Americas. Our results provide a fine-scale characterization of the source populations, identify a series of novel, previously unreported contributions from Africa and Europe and highlight geohistorical structure in the ancestry of American admixed populations

Projecting Ancient Ancestry in Modern-Day Arabians and Iranians: A Key Role of the Past Exposed Arabo-Persian Gulf on Human Migrations

The Arabian Peninsula is strategic for investigations centered on the early structuring of modern humans in the wake of the out-of-Africa migration. Despite its poor climatic conditions for the recovery of ancient human DNA evidence, the availability of both genomic data from neighboring ancient specimens and informative statistical tools allow modeling the ancestry of local modern populations. We applied this approach to a data set of 741,000 variants screened in 291 Arabians and 78 Iranians, and obtained insightful evidence. The west-east axis was a strong forcer of population structure in the Peninsula, and, more importantly, there were clear continuums throughout time linking western Arabia with the Levant, and eastern Arabia with Iran and the Caucasus. Eastern Arabians also displayed the highest levels of the basal Eurasian lineage of all tested modern-day populations, a signal that was maintained even after correcting for a possible bias due to a recent sub-Saharan African input in their genomes. Not surprisingly, eastern Arabians were also the ones with highest similarity with Iberomaurusians, who were, so far, the best proxy for the basal Eurasians amongst the known ancient specimens. The basal Eurasian lineage is the signature of ancient non-Africans who diverged from the common European-eastern Asian pool before 50,000 years ago, prior to the later interbred with Neanderthals. Our results appear to indicate that the exposed basin of the Arabo-Persian Gulf was the possible home of basal Eurasians, a scenario to be further investigated by searching ancient Arabian human specimens.This work was financed by FEDER-Fundo Europeu de Desenvolvimento Regional funds through COMPETE 2020-Operacional Programme for Competitiveness and Internationalization (POCI), Portugal 2020, by Portuguese funds through FCT-Fundação para a Ciência e a Tecnologia, Ministério da Ciência, Tecnologia e Inovação in the framework of the project “Biomedical anthropological study in Arabian Peninsula based on high-throughput genomics” (POCI-01-0145-FEDER-016609), the Italian Ministry of Education, University and Research project Dipartimenti di Eccellenza Program (2018–2022)—Department of Biology and Biotechnology “L. Spallanzani,” University of Pavia (to A.T.). V.F. has a postdoc grant through FCT (SFRH/BPD/114927/2016). i3S is financed by FEDER-COMPETE 2020, Portugal 2020 and by Portuguese funds through FCT in the framework of the project “Institute for Research and Innovation in Health Sciences” (POCI-01-0145-FEDER-007274). Authors would like to thank Dr Francesco Bertolini for facilitating the research of A.R. in the last stage of the article preparation

Electrostatic mechanophores in tuneable light-emitting piezo-polymer nanowires

Electromechanical coupling through piezoelectric polymer chains allows the emission of organic molecules in active nanowires to be tuned. This effect is evidenced by highly bendable arrays of counter-ion dye-doped nanowires made of a poly(vinylidenefluoride) copolymer. A reversible redshift of the dye emission is found upon the application of dynamic stress during highly accurate bending experiments. By density functional theory calculations it is found that these photophysical properties are associated with mechanical stresses applied to electrostatically interacting molecular systems, namely to counterion-mediated states that involve light-emitting molecules as well as charged regions of piezoelectric polymer chains. These systems are an electrostatic class of supramolecular functional stress-sensitive units, which might impart new functionalities in hybrid molecular nanosystems and anisotropic nanostructures for sensing devices and soft robotics.Comment: 32 pages, 18 figure

Atorvastatin pretreatment improves outcomes in patients with acute coronary syndromes undergoing early percutaneous coronary intervention: results of the ARMYDA-ACS randomized trial.

This study sought to investigate potential protective effects of atorvastatin in patients with acute coronary syndromes (ACS) undergoing percutaneous coronary intervention (PCI). Background Randomized studies have shown that pretreatment with atorvastatin may reduce periprocedural myocardial infarction in patients with stable angina during elective PCI; however, this therapy has not been tested in patients with ACS. Methods A total of 171 patients with non–ST-segment elevation ACS were randomized to pretreatment with atorvastatin (80 mg 12 h before PCI, with a further 40-mg preprocedure dose [n 86]) or placebo (n 85). All patients were given a clopidogrel 600-mg loading dose. All patients received long-term atorvastatin treatment thereafter (40 mg/day). The main end point of the trial was a 30-day incidence of major adverse cardiac events (death, myocardial infarction, or unplanned revascularization). Results The primary end point occurred in 5% of patients in the atorvastatin arm and in 17% of those in the placebo arm (p 0.01); this difference was mostly driven by reduction of myocardial infarction incidence (5% vs. 15%; p 0.04). Postprocedural elevation of creatine kinase-MB and troponin-I was also significantly lower in the atorvastatin group (7% vs. 27%, p 0.001 and 41% vs. 58%, p 0.039, respectively). At multivariable analysis, pretreatment with atorvastatin conferred an 88% risk reduction of 30-day major adverse cardiac events (odds ratio 0.12, 95% confidence interval 0.05 to 0.50; p 0.004). Conclusions The ARMYDA-ACS trial indicates that even short-term pretreatment with atorvastatin may improve outcomes in patients with ACS undergoing early invasive strategy. These findings may support routine use of high-dose statins before intervention in patients with ACS

Genomic and personalized medicine approaches for substance use disorders (SUDs) looking at genome-wide association studies

Drug addiction, or substance use disorder (SUD), is a chronic, relapsing disorder in which compulsive drug-seeking and drug-taking behaviour persist despite serious negative consequences. Drug abuse represents a problem that deserves great attention from a social point of view, and focuses on the importance of genetic studies to help in understanding the genetic basis of addiction and its medical treatment. Despite the complexity of drug addiction disorders, and the high number of environmental variables playing a role in the onset, recurrence, and duration of the symptoms, several studies have highlighted the non-negligible role of genetics, as demonstrated by heritability and genome-wide association studies. A correlation between the relative risk of addiction to specific substances and heritability has been recently observed, suggesting that neurobiological mechanisms may be, at least in part, inherited. All these observations point towards a scenario where the core neurobiological factors of addiction, involving the reward system, impulsivity, compulsivity, stress, and anxiety response, are transmitted, and therefore, genes and mutations underlying their variation might be detected. In the last few years, the development of new and more efficient sequencing technologies has paved the way for large-scale studies in searching for genetic and epigenetic factors affecting drug addiction disorders and their treatments. These studies have been crucial to pinpoint single nucleotide polymorphisms (SNPs) in genes that affect the reaction to medical treatments. This is critically important to identify pharmacogenomic approaches for substance use disorder, such as OPRM1 SNPs and methadone required doses for maintenance treatment (MMT). Nevertheless, despite the promising results obtained by genome-wide association and pharmacogenomic studies, specific studies related to population genetics diversity are lacking, undermining the overall applicability of the preliminary findings, and thus potentially affecting the portability and the accuracy of the genetic studies. In this review, focusing on cannabis, cocaine and heroin use, we report the state-of-the-art genomics and pharmacogenomics of SUDs, and the possible future perspectives related to medical treatment response in people that ask for assistance in solving drug-related problems

Detecting Genetic Isolation in Human Populations: A Study of European Language Minorities

The identification of isolation signatures is fundamental to better understand the genetic structure of human populations and to test the relations between cultural factors and genetic variation. However, with current approaches, it is not possible to distinguish between the consequences of long-term isolation and the effects of reduced sample size, selection and differential gene flow. To overcome these limitations, we have integrated the analysis of classical genetic diversity measures with a Bayesian method to estimate gene flow and have carried out simulations based on the coalescent. Combining these approaches, we first tested whether the relatively short history of cultural and geographical isolation of four "linguistic islands" of the Eastern Alps (Lessinia, Sauris, Sappada and Timau) had left detectable signatures in their genetic structure. We then compared our findings to previous studies of European population isolates. Finally, we explored the importance of demographic and cultural factors in shaping genetic diversity among the groups under study. A combination of small initial effective size and continued genetic isolation from surrounding populations seems to provide a coherent explanation for the diversity observed among Sauris, Sappada and Timau, which was found to be substantially greater than in other groups of European isolated populations. Simulations of micro-evolutionary scenarios indicate that ethnicity might have been important in increasing genetic diversity among these culturally related and spatially close populations. © 2013 Capocasa et al