Exceptionally large two- and three-photon absorption cross-sections by OPV organometalation

Oligo(p-phenylenevinylene)s (OPVs) containing up to 8 PV units and end-functionalized by ruthenium alkynyl groups have been prepared and their nonlinear absorption properties assessed using the Z-scan technique and employing low repetition rate femtosecond pulses. Exceptionally large two-photon absorption (ca. 12 500 GM at 725 nm) and three-photon absorption cross sections (ca. 1.6 × 10⁻⁷⁶ cm⁶s² at 1100 nm) are found for the 8PV-containing example, highlighting the potential of an “organometalation” approach to NLO-efficient organic materialsWe thank the Australian Research Council (ARC), the National Natural Science Foundation of China (51432006), the Chinese Government Ministry of Education, the Chinese Government State Administration of Foreign Experts Affairs (111 Project: B13025), and the National Science Centre of Poland (grant 2013/10/A/ST4/00114) for financial support. M. P. C. thanks the ARC for an Australian Research Fellowship and C. Q. thanks CONICYT (Chile) for a Chile PhD Scholarship Abroad

Administracja, zarządzanie i handel zagraniczny w warunkach integracji. Materiały konferencyjne - Zarządzanie bezpieczeństwem

Ze wstępu: "Bezpieczeństwo jest w coraz wyższej cenie. Zajmują się nim naukowcy oraz praktycy z różnych dziedzin. W najszerszym wymiarze pojęcie „bezpieczeństwo” sprowadzić można do słów: stan niezagrożenia, spokoju, pewności. Takie ogólne ujęcie problematyki bezpieczeństwa sprawia, że różne podmioty podchodzą wybiórczo do tych bardzo ważnych zarówno dla pojedynczych ludzi, jak i społeczeństwa zagadnień. Inaczej postrzegają i interpretują bezpieczeństwo politycy, prawnicy, ekonomiści, wojskowi, policjanci, lekarze, pedagodzy, a inaczej zwyczajni ludzie. W ich ujęciu bezpieczeństwo to: 1) stan świadomości człowieka, w którym czuje się on wolny od jakichkolwiek zagrożeń, pociągający za sobą poczucie spokoju i komfortu; 2) niczym niezakłócone współistnienie człowieka z innymi ludźmi i środowiskiem przyrodniczym; 3) stan bez lęku i niepokoju o siebie i innych, pewność jutra; 4) brak zagrożenia utraty zdrowia, mienia i życia, komfort psychiczny umożliwiający realizację życiowych marzeń i celów; 5) sytuacja, w której człowiekowi nic nie zagraża, a w nagłych i nieprzewidzianych sytuacjach może liczyć na pomoc i wsparcie innych."(...

2,5-Bis(azulenyl) pyrrolo[3,2-b] pyrroles - the key influence of the linkage position on the linear and nonlinear optical properties

The first route towards pyrrolo[3,2-b] pyrroles containing two azulene moieties at positions 2 and 5 was developed. The key step of this approach is the three-step transformation of pyridine scaffolds into azulene via sequential N-arylation followed by ring-opening and a reaction with cyclopentadiene. The resulting quadrupolar acceptor-donor-acceptor compounds possess interesting optical properties such as bathochromically shifted absorption with the magnitude of the red-shift strongly dependent on the linkage position. Two-photon absorption of these functional dyes is markedly different from that of previously described pyrrolo[3,2-b] pyrroles. The experimental optical spectra were rationalized using time-dependent density functional theory calculations of both the linear and nonlinear optical properties

Two-Photon Macromolecular Probe Based on a Quadrupolar Anthracenyl Scaffold for Sensitive Recognition of Serum Proteins under Simulated Physiological Conditions

International audienceThe binding interaction of a biocompatible water-soluble polycationic two-photon fluorophore (Ant-PIm) toward human serum albumin (HSA) was thoroughly investigated under simulated physiological conditions using a combination of steady-state, time-resolved, and two-photon excited fluorescence techniques. The emission properties of both Ant-PIm and the fluorescent amino acid residues in HSA undergo remarkable changes upon complexation allowing the thermodynamic profile associated with Ant-PIm–HSA complexation to be accurately established. The marked increase in Ant-PIm fluorescence intensity and quantum yield in the proteinous environment seems to be the outcome of the attenuation of radiationless decay pathways resulting from motional restriction imposed on the fluorophore. Fluorescence resonance energy transfer and site-marker competitive experiments provide conclusive evidence that the binding of Ant-PIm preferentially occurs within the subdomain IIA. The pronounced hypsochromic effect and increased fluorescence enhancement upon association with HSA, compared to that of bovine serum albumin (BSA) and other biological interferents, makes the polymeric Ant-PIm probe a valuable sensing agent in rather complex biological environments, allowing facile discrimination between the closely related HSA and BSA. Furthermore, the strong two-photon absorption (TPA) with a maximum located at 820 nm along with a TPA cross section σ2 > 800 GM, and the marked changes in the position and intensity of the band upon complexation definitely make Ant-PIm a promising probe for two-photon excited fluorescence-based discrimination of HSA from BSA

Influence of Active Exposure to Tobacco Smoke on Nitric Oxide Status of Pregnant Women

Smoking tobacco can impair proper vascular endothelial functioning. This is exhibited through reduced nitric oxide synthesis as well as activity due to accompanying oxidative stress. We examined the relationship between nitric oxide and markers of oxidative stress/antioxidant defense in serum of smoking and non-smoking pregnant women. Subjects included 99 healthy pregnant women, who were tested for nitric oxide (NO), endothelial (eNOS) and inducible (iNOS) nitric oxide synthase, total oxidant capacity (TOC), and total antioxidant capacity (TAC). NO, eNOS, and TAC serum concentrations were significantly lower (p < 0.005), but iNOS (p < 0.05) and TOC (p < 0.001) were higher in smokers than in non-smokers. Multivariate regression analysis showed associations between NO concentration and eNOS, TAC, and smoking status in the whole group of patients. In the model estimated separately for smokers, the highest impact of eNOS (β = 0.375; p = 0.021) and cotinine (β = −0.323; p = 0.037) was indicated for NO concentration. In the model of non-smokers, eNOS (β = 0.291, p = 0.030) and TAC (β = 0.350; p = 0.015) were important for NO level. Smoking during pregnancy could exacerbate oxidative stress, impair the action of nitric oxide synthases, and adversely affect the balance of oxygen and nitrogen metabolism. Relationships between NO concentrations and TAC in the studied women’s blood can confirm the antioxidant nature of nitric oxide

Specific Recognition of G-Quadruplexes Over Duplex-DNA by a Macromolecular NIR Two-Photon Fluorescent Probe

International audienceThe implication of guanine-rich DNA sequences in biologically important roles such as telomerase dysfunction and the regulation of gene expression has prompted the search for structure-specific G-quadruplex agents for targeted diagnostic and therapeutic applications. Herein, we report on a near-infrared (NIR) two-photon poly(cationic) anthracene-based macromolecule able to selectively target G-quadruplexes (G4s) over genomic double-stranded DNA. In particular, the striking changes in its linear and third-order nonlinear optical properties, combined with the emergence of a strong induced electronic circular dichroism (ECD) signal upon binding to canonical and noncanonical DNA secondary structures allowed for a highly specific detection of several different G4s. Furthermore, through a detailed computational analysis we bring compelling evidence that our probe intercalation within G4s is a thermodynamically favored event, and we fully rationalize the spectroscopic evolution resulting from this complexation event by providing a reasonable explanation regarding the origin of the peculiar ECD effect that accompanies it

Alirocumab and cardiovascular outcomes after acute coronary syndrome

BACKGROUN

Alirocumab and Cardiovascular Outcomes after Acute Coronary Syndrome

BACKGROUN