322 research outputs found

    Novel solid-state emissive polymers and polymeric blends from a T-Shaped benzodifuran scaffold: A comparative study

    Get PDF
    Two novel polyimines were synthesized from a benzodifuran based diamino monomer and two dialdehydes bearing bulky groups and a flexible spacer. The polymers display tuned luminescence performance according to the presence of half-salen groups. The effect of the intramolecular bond on the emission properties were examined. Two model compounds, replicating the same emissive Schiff base cores, were synthetized. From the models, dye-doped blends in the fluorophore/matrix ratio, resembling the polymers, were produced. Amorphous thin films of the covalent polymers and the polymeric blends were obtained by spin-coating technique. The Photoluminescent (PL) response of the different macromolecular systems were qualitatively and quantitatively examined and compared

    A stochastic delay differential model of cerebral autoregulation

    Get PDF
    Mathematical models of the cardiovascular system and of cerebral autoregulation (CAR) have been employed for several years in order to describe the time course of pressures and flows changes subsequent to postural changes. The assessment of the degree of efficiency of cerebral auto regulation has indeed importance in the prognosis of such conditions as cerebro-vascular accidents or Alzheimer. In the quest for a simple but realistic mathematical description of cardiovascular control, which may be fitted onto non-invasive experimental observations after postural changes, the present work proposes a first version of an empirical Stochastic Delay Differential Equations (SDDEs) model. The model consists of a total of four SDDEs and two ancillary algebraic equations, incorporates four distinct delayed controls from the brain onto different components of the circulation, and is able to accurately capture the time course of mean arterial pressure and cerebral blood flow velocity signals, reproducing observed auto-correlated error around the expected drift

    Inheritance Law and Investment in Family Firms

    Get PDF
    Entrepreneurs may be legally bound to bequeath a minimal stake to non-controlling heirs. The size of this stake can reduce investment in family firms, by reducing the future income they can pledge to external financiers. Using a purpose-built indicator of the permissiveness of inheritance law and data for 10,004 firms from 38 countries in 1990-2006, we find that stricter inheritance law is associated with lower investment in family firms, but does not affect investment in non-family firms. Moreover, as the model predicts, inheritance law affects investment only in family firms that experience a succession

    A highly water-soluble fluorescent and colorimetric pH probe

    Get PDF
    A new 5-(4-((2-(benzothiazole-2-carbonyl)hydrazono)methyl)-3-hydroxyphenoxy)N,N,N-trimethylpentan-1-aminium bromide (BTABr) fluorescent and colorimetric pH probe was easily synthesized by the condensation reaction of benzothiazole-2-carbohydrazide with 5-(4-formyl-3-hydroxyphenoxy)-N,N,N-trimethylpentan-1-aminium bromide. The benzothiazole moiety provided the emissive part of the molecule and the charged trimethyl amino group guaranteed outstanding solubility in water, for an organic molecule. pH titration experiments indicated that the probe is useful for monitoring acidic and alkaline solutions, turning reversibly in color/fluorescence just at a neutral pH value. Naked-eye colorimetric response was observed both in solution and in the solid state. In addition, the probe showed high stability and selectivity and large Stokes shifts. Because of these features, BTABr can potentially work as an on-off real-time pH sensor for intracellular pH imaging. The crystal structure of BTABr examined by single-crystal analysis showed a planar geometry of the molecule and confirmed the presence of a molecular stacking between molecules joined in a complex tridimensional hydrogen bonding pattern

    Vibrational analysis of paraelectric–ferroelectric transition of linbo3: An ab-initio quantum mechanical treatment

    Get PDF
    The phase transitions between paraelectric (PE) and ferroelectric (FE) isomorph phases of LiNbO3 have been investigated quantum mechanically by using a Gaussian-type basis set, the B3LYP hybrid functional and the CRYSTAL17 code. The structural, electronic and vibrational properties of the two phases are analyzed. The vibrational frequencies evaluated at the Γ point indicate that the paraelectric phase is unstable, with a complex saddle point with four negative eigenvalues. The energy scan of the A2u mode at −215 cm−1 (i215) shows a dumbbell potential with two symmetric minima. The isotopic substitution, performed on the Li and Nb atoms, allows interpretation of the nontrivial mechanism of the phase transition. The ferroelectric phase is more stable than the paraelectric one by 0.32 eV

    Spatial variability of nitrogen dioxide and formaldehydeand residential exposure of children in the industrial area of Viadana, Northern Italy

    Get PDF
    Chipboard production is a source of ambient air pollution. We assessed the spatial variability of outdoor pollutants and residentialexposure of children living in proximity to the largest chipboard industry in Italy and evaluated the reliability of exposureestimates obtained from a number of available models. We obtained passive sampling data on NO2and formaldehyde collectedby the Environmental Protection Agency of Lombardy region at 25 sites in the municipality of Viadana during 10 weeks (2017-2018) and compared NO2measurements with average weekly concentrations from continuous monitors. We compared interpo-lated NO2and formaldehyde surfaces with previous maps for 2010. We assessed the relationship between residential proximity tothe industry and pollutant exposures assigned using these maps, as well as other available countrywide/continental models basedon routine data on NO2, PM10, andPM2.5. The correlation between NO2concentrations from continuous and passive samplingwas high (Pearson'sr= 0.89), although passive sampling underestimated NO2especially during winter. For both 2010 and 2017-2018, we observed higher NO2and formaldehyde concentrations in the south of Viadana, with hot-spots in proximity to theindustry. PM10and PM2.5exposures were higher for children at 3.5 km to theindustry, whereas NO2exposure was higher at 1-1.7 km to the industry. Road and population densities were also higher close tothe industry. Findings from a variety of exposure models suggest that children living in proximity to the chipboard industry inViadana are more exposed to air pollution and that exposure gradients are relatively stable over time

    Effect of indoor nitrogen dioxide on lung function in urban environment

    Get PDF
    Background: High levels of indoor NO2 are associated with increased asthma symptoms and decreased expiratory peak flows in children. We investigated the association of exposure to domestic indoor NO2, objectively measured in winter and spring, with respiratory symptoms and lung function in a sample of adolescents from a southern Mediterranean area. Methods: From a large school population sample (n=2150) participating in an epidemiological survey in the urban area of the City of Palermo (southern Italy), a sub-sample of 303 adolescents was selected which furnished an enriched sample for cases of current asthma. All subjects were evaluated by a health questionnaire, skin prick tests and spirometry. One-week indoor NO2 monitoring of their homes was performed by diffusive sampling during spring and again during winter. Results: We found that about 25% of subjects were exposed to indoor NO2 levels higher than the 40μg/m3 World Health Organization limit, during both spring and winter. Moreover, subjects exposed to the highest indoor NO2 concentrations had increased frequency of current asthma (p=0.005), wheeze episodes in the last 12 months (p<0.001), chronic phlegm (p=0.013), and rhinoconjunctivitis (p=0.008). Finally, subjects with a personal history of wheeze ever had poorer respiratory function (FEF25-75%, p=0.01) when exposed to higher indoor NO2 concentrations. Conclusions: Home exposure to high indoor NO2 levels frequently occurs in adolescents living in a southern Mediterranean urban area and is significantly associated with the risks for increased frequency of both respiratory symptoms and reduced lung function

    Congenital hypothyroidism due to a new deletion in the sodium/iodide symporter protein.

    Get PDF
    OBJECTIVE: Iodide transport defect (ITD) is a rare disorder characterised by an inability of the thyroid to maintain an iodide gradient across the basolateral membrane of thyroid follicular cells, that often results in congenital hypothyroidism. When present the defect is also found in the salivary glands and gastric mucosa and it has been shown to arise from abnormalities of the sodium/iodide symporter (NIS). PATIENT: We describe a woman with hypothyroidism identified at the 3rd month of life. The diagnosis of ITD was suspected because of nodular goitre, and little if any iodide uptake by the thyroid and salivary glands. Treatment with iodide partially corrected the hypothyroidism; however, long-term substitution therapy with L-thyroxine was started. MEASUREMENTS: Thyroid radioiodide uptake was only 1.4% and 0.3% at 1 and 24 h after the administration of recombinant human TSH. The saliva to plasma I- ratio was 1.1 indicating that the inability of the thyroid gland to concentrate I- was also present in the salivary glands. RESULTS: Analysis of the patient's NIS gene revealed a 15 nucleotide (nt) deletion of the coding sequence (nt 1314 through nt 1328) and the insertion of 15 nt duplicating the first 15 nt of the adjacent intron. The patient was homozygous for this insertion/deletion, while both consanguineous parents were heterozygous. This deletion predicts the production of a protein lacking the five terminal amino acids of exon XI (439-443) which are located in the 6th intracellular loop. COS-7 cells transfected with a vector expressing the mutant del-(439-443) NIS failed to concentrate iodide, suggesting that the mutation was the direct cause of the ITD in this patient. CONCLUSION: In conclusion we describe the first Italian case of congenital hypothyroidism due to a new deletion in the NIS gene
    • …
    corecore