49 research outputs found
Investigation of the long effective conjugation length in defect-free insulated molecular wires
Due to the âinsulationâ of the Ï-conjugated backbones, insulated molecular wires (IMWs) are expected to be applied to various optoelectronic applications and nanotechnology.[1] Recently, Kazunori et al have succeeded in the synthesis of a self-threading polythiophene with a polyrotaxane-like 3D architecture (PSTB, see Figure 1), for which an intrawire hole mobility of 0.9 cm2 Vâ1 sâ1 has been measured.[2] Here, we aim to evaluate the extent of Ï-conjugation along polythiophene backbones sheathed within defect-free âinsulatingâ layers. A comparison between the experimental Raman spectra of the self-threading oligomers (i.e. 2STB-5STB) and the corresponding PSTB polymer indicates that: (i) the ratio of relative intensities of the two most intense Raman bands (I1375/1445) increases with the elongation of the size chain but does not saturate up to the pentamer, and (ii) Ï-conjugation spreads over 17â18 thiophene units in the polymer. Whether the effective conjugation length of the polymer is better described by using the long oligomer extrapolation approach[3] or periodic DFT calculations of the polymer is discussed in detailed by exploiting the very recent potentialities of state-of-the-art quantum chemical simulations of vibrational properties for crystalline solids.[Universidad de MĂĄlaga. Campus de Excelencia Internacional AndalucĂa Tech
Molecular and electronic structure investigation of encapsulated polytiophenes
Insulated molecular wires (IMWs) are expected to be applied to various optoelectronic applications due to their unique photophysical, electronic, and mechanical properties which originate from the absence of -stacking.[1] Kazunori et al have succeeded in the synthesis of a self-threading polythiophene with a polyrotaxane-like 3D architecture (PSTB, see Figure 1a), for which an intrawire hole mobility of 0.9 cm2 Vâ1 sâ1 has been measured.[2] In this study we aim to evaluate for the first time the extension of the -conjugation in encapsulated polythiophenes. A comparison between the experimental Raman spectra of the self-threading PSTB polymer with their correspondent oligomers (i.e. 2STB-5STB) suggests that the effective conjugation length in the polymer is longer than five monomer units. Whether the effective conjugation length of the polymer is better described by using the long oligomer extrapolation approach or periodic DFT calculations of the polymer is discussed in detailed by exploiting the very recent potentialities of state-of-the-art quantum chemical simulations of vibrational properties for crystalline solids.Universidad de MĂĄlaga. Campus de Excelencia Internacional AndalucĂa Tec
COVID-19 diagnosis and SARS-CoV-2 viral load in hospitalized patients versus people with Flu-Like Syndrome
At the beginning of the pandemic, the Brazilian Public Health System (SUS) did not to test all suspects cases of COVID-19, thus, hospitalized individuals, health professionals, and symptomatic contacts were prioritized. Contrary to the criteria adopted by the government, the municipality of Botucatu chose to test all people who manifested flu-like syndrome. We aimed to investigate whether positive cases for COVID-19 were more frequent in patients seeking diagnosis via SUS or in the group of people seeking diagnosis via Municipal Health Center and whether the viral load was expressed differently in hospitalized patients (HP) compared to mild symptoms (MHC). Results showed that there were no differences in the percentage between the groups. Regarding the viral load, significant differences were found between the samples from HP and MHC (3-10 days of symptoms), with HP presenting a lower viral load. The results provide significant information about the viral load at different time-lapses
Clinical Learning Environment And Graduating Nursing Studentsâ Competence: A MultiâCountry CrossâSectional Study
The purpose of this study was to explore nursing studentsâ perceptions of their final clinical learning environment and its association with their selfâassessed competence, satisfaction with nursing education and turnover intentions at graduation in six European countries. A multiâcountry comparative crossâsectional study was conducted with nursing students (n = 1,746) from the Czech Republic, Finland, Italy, Portugal, Slovakia and Spain using the Nurse Competence Scale and the Clinical Learning Environment and Supervision scale. Nursing studentsâ overall perceptions of their final clinical learning environment and supervision were positive in all the countries studied. The correlation between the studentsâ perceptions of their final clinical learning environment and competence was statistically significant and positive. Satisfaction with the nursing programme and clinical practicum and no consideration of career change were related to positive perceptions of the final clinical learning environment. Highlighting the importance of the supervisory relationship and pedagogical atmosphere, nursing studentsâ positive perceptions of the final clinical learning environment and supervision contribute to a better level of selfâassessed competence and satisfaction with the nursing programme and clinical practicum, leading to lower turnover intentions.</p
LIME -- a gas TPC prototype for directional Dark Matter search for the CYGNO experiment
The CYGNO experiment aims at the development of a large gaseous TPC with
GEM-based amplification and an optical readout by means of PMTs and scientific
CMOS cameras for 3D tracking down to O(keV) energies, for the directional
detection of rare events such as low mass Dark Matter and solar neutrino
interactions. The largest prototype built so far towards the realisation of the
CYGNO experiment demonstrator is the 50 L active volume LIME, with 4 PMTs and a
single sCMOS imaging a 3333 cm\textsuperscript{2} area for 50 cm drift,
that has been installed in underground Laboratori Nazionali del Gran Sasso in
February 2022. We will illustrate LIME performances as evaluated overground in
Laboratori Nazionali di Frascati by means of radioactive X-ray sources, and in
particular the detector stability, energy response and energy resolution. We
will discuss the MC simulation developed to reproduce the detector response and
show the comparison with actual data. We will furthermore examine the
background simulation worked out for LIME underground data taking and
illustrate the foreseen expected measurement and results in terms of natural
and materials intrinsic radioactivity characterisation and measurement of the
LNGS underground natural neutron flux. The results that will be obtained by
underground LIME installation will be paramount in the optimisation of the
CYGNO demonstrator, since this is foreseen to be composed by multiple modules
with the same LIME dimensions and characteristics
Signal-On Fluorescent Imprinted Nanoparticles for Sensing of Phenols in Aqueous Olive Leaves Extracts
The activation of signals in fluorescent nanosensors upon interaction with their targets is highly desirable. To this aim, several molecularly imprinted nanogels have been synthetized for the recognition of tyrosol, hydroxytyrosol and oleuropein in aqueous extracts using the non-covalent approach. Two of them contain fluorescein derivatives as co-monomers, and their fluorescence emission is switched on upon binding of the target phenols. The selection of functional monomers was previously done by analyzing the interactions by nuclear magnetic resonance (NMR) in deuterated dimethylsulfoxide (DMSO-d6) of the monomers with tyrosol and hydroxytyrosol. Polymers were synthetized under high dilution conditions to obtain micro- and nano-particles, as verified by transmission electron microscopy (TEM). 1,4-Divinylbenzene (DVB) was used in the fluorescent polymers in order to enhance the interactions with the aromatic ring of the templates tyrosol and hydroxytyrosol by \u3c0-\u3c0 stacking. The results were fully satisfactory as to rebinding: DVB-crosslinked molecularly imprinted polymers (MIPs) gave over 50 nmol/mg rebinding. The sensitivity of the fluorescent MIPs was excellent, with LODs in the pM range. The sensing polymers were tested on real olive leaves extracts, with very good performance and negligible matrix effects
Effects of irrigation on yield components and quality of walnut cultivar âChandlerâ
In Italy walnut cultivation is mainly concentrated in Campania region, where traditional and new specialized orchard coexist and international cultivars are utilized for the new plantations. The growth and productivity of the international, high yielding cultivar âChandlerâ grown in the dry summer conditions of Naples province has been examined during a two year irrigation trial. Three treatments were applied: an un-irrigated control and two different levels of water supply, corresponding respectively to the restitution of 50 and 100% ET0 by means of a drip irrigation system. Plant growth and nut and kernel weight increased at the highest irrigation volume, while nut fall at ripening was more concentrated in the un-irrigated control. The percentage of defected nuts was higher in condition of limited water availability. The restitution of 50% ET0 assured satisfactory levels of production and saving of irrigation water