181 research outputs found
Modelling the structural disorder in trigonal-prismatic coordinated transition metal dichalcogenides
Trigonal-prismatic coordinated transition metal dichalcogenides (TMDCs) are formed from stacked (chalcogen)-(transition metal)-(chalcogen) triple layers, where the chemical bond is covalent within the triple layers and van der Waals (vdW) forces are effective between the layers. Bonding is at the origin of the great interest in these compounds, which are used as 2D materials in applications such as catalysis, electronics, photoelectronics, sensors, batteries and thermoelectricity. This paper addresses the issue of modelling the structural disorder in multilayer TMDCs. The structural model takes into account stacking faults, correlated displacement of atoms and average crystallite size/shape, and is assessed by simulation of the X-ray diffraction pattern and fitting to the experimental data relative to a powdered sample of MoS2 exfoliated and restacked via lithiation. From fitting, an average crystallite size of about 50 angstrom, nearly spherical crystallites and a definite probability of deviation from the fully eclipsed atomic arrangement present in the ordered structure are determined. The increased interlayer distance and correlated intralayer and interlayer atomic displacement are attributed to the presence of lithium intercalated in the vdW gap between triple layers (Li/Mo molar ratio of about 0.06). The model holds for the whole class of trigonal-prismatic coordinated TMDCs, and is suitably flexible to take into account different preparation routes
Analyzing post modern consumer behavior and beef consumption patterns: Insights from Sicilian market
In current events, consumers are subject to various stimuli (advertising campaigns, popular magazines, social) that affect their marginal consumption propensity. However, as Economic Theory teaches us, the marginal propensity to consume does not necessarily translate into consumer spending. This is strongly affected by consumers' eating habits and other variables that determine where the consumption phenomenon occurs. The study aims to analyze post-modern consumer behavior toward beef consumption. An online questionnaire was administered to 535 Sicilian participants to achieve this goal. Statistical analyses were performed by R statistical software, using two-tailed P-values, and setting statistical significance at P <= 0.05. The results show that consumption choices are influenced by beef meat's impact on health. In addition, consumers consider the origin and certifications of the raw material to be extremely crucial
Coherent anti-Stokes Raman spectroscopy of single and multi-layer graphene
Abstract: Spontaneous Raman spectroscopy is a powerful characterization tool for graphene research. Its extension to the coherent regime, despite the large nonlinear third-order susceptibility of graphene, has so far proven challenging. Due to its gapless nature, several interfering electronic and phononic transitions concur to generate its optical response, preventing to retrieve spectral profiles analogous to those of spontaneous Raman. Here we report stimulated Raman spectroscopy of the G-phonon in single and multi-layer graphene, through coherent anti-Stokes Raman Scattering. The nonlinear signal is dominated by a vibrationally non-resonant background, obscuring the Raman lineshape. We demonstrate that the vibrationally resonant coherent anti-Stokes Raman Scattering peak can be measured by reducing the temporal overlap of the laser excitation pulses, suppressing the vibrationally non-resonant background. We model the spectra, taking into account the electronically resonant nature of both. We show how coherent anti-Stokes Raman Scattering can be used for graphene imaging with vibrational sensitivity
The burden of Candida species colonization in NICU patients: a colonization surveillance study
Fungal infections are an important cause
of morbidity and mortality in neonatal
intensive care units (NICUs). The identification
of specific risk factors supports prevention
of candidemia in neonates. Effective
prophylactic strategies have recently
become available, but the identification
and adequate management of high-risk infants
is still a priority. Prior colonization is
a key risk factor for candidemia. For this
reason, surveillance studies to monitor incidence,
species distribution, and antifungal
susceptibility profiles, are mandatory.
Among 520 infants admitted to our NICU
between January 2013 and December
2014, 472 (90.77%) were included in the
study. Forty-eight out of 472 (10.17%) patients
tested positive for Candida spp. (C.),
at least on one occasion. All the colonized
patients tested positive for the rectal swab,
whereas 7 patients also tested positive for
the nasal swab. Fifteen out of 472 patients
(3.18%) had more than one positive rectal
or nasal swab during their NICU stay.
Moreover, 9 out of 15 patients tested negative
at the first sampling, suggesting they
acquired Candida spp. during their stay.
Twenty-five of forty-eight (52.1%) colonized
patients carried C.albicans and 15/48
(31.25%) C.parapsilosis. We identified as
risk factors for Candida spp. colonization:
antibiotic therapy, parenteral nutrition,
the use of a central venous catheter, and
nasogastric tube. Our experience suggests
that effective microbiological surveillance
can allow for implementing proper, effective
and timely control measures in a highrisk
setting
Investigating the epi-miRNome: Identification of epi-miRNAs using transfection experiments
Aim: Growing evidence shows a strong interplay between post-transcriptional regulation, mediated by miRNAs (miRs) and epigenetic regulation. Nevertheless, the number of experimentally validated miRs (called epi-miRs) involved in these regulatory circuitries is still very small. Material & methods: We propose a pipeline to prioritize candidate epi-miRs and to identify potential epigenetic interactors of any given miR starting from miR transfection experiment datasets. Results & conclusion: We identified 34 candidate epi-miRs: 19 of them are known epi-miRs, while 15 are new. Moreover, using an in-house generated gene expression dataset, we experimentally proved that a component of the polycomb-repressive complex 2, the histone methyltransferase enhancer of zeste homolog 2 (EZH2), interacts with miR-214, a well-known prometastatic miR in melanoma and breast cancer, highlighting a miR-214-EZH2 regulatory axis potentially relevant in tumor progression
Thermodynamical Consistent Modeling and Analysis of Nematic Liquid Crystal Flows
The general Ericksen-Leslie system for the flow of nematic liquid crystals is
reconsidered in the non-isothermal case aiming for thermodynamically consistent
models. The non-isothermal model is then investigated analytically. A fairly
complete dynamic theory is developed by analyzing these systems as quasilinear
parabolic evolution equations in an -setting. First, the existence of
a unique, local strong solution is proved. It is then shown that this solution
extends to a global strong solution provided the initial data are close to an
equilibrium or the solution is eventually bounded in the natural norm of the
underlying state space. In these cases, the solution converges exponentially to
an equilibrium in the natural state manifold
- …