6,097 research outputs found
Nanoscale roughness and morphology affect the IsoElectric Point of titania surfaces
We report on the systematic investigation of the role of surface nanoscale
roughness and morphology on the charging behaviour of nanostructured titania
(TiO2) surfaces in aqueous solutions. IsoElectric Points (IEPs) of surfaces
have been characterized by direct measurement of the electrostatic double layer
interactions between titania surfaces and the micrometer-sized spherical silica
probe of an atomic force microscope in NaCl aqueous electrolyte. The use of a
colloidal probe provides well-defined interaction geometry and allows
effectively probing the overall effect of nanoscale morphology. By using
supersonic cluster beam deposition to fabricate nanostructured titania films,
we achieved a quantitative control over the surface morphological parameters.
We performed a systematical exploration of the electrical double layer
properties in different interaction regimes characterized by different ratios
of characteristic nanometric lengths of the system: the surface rms roughness
Rq, the correlation length {\xi} and the Debye length {\lambda}D. We observed a
remarkable reduction by several pH units of IEP on rough nanostructured
surfaces, with respect to flat crystalline rutile TiO2. In order to explain the
observed behavior of IEP, we consider the roughness-induced self-overlap of the
electrical double layers as a potential source of deviation from the trend
expected for flat surfaces.Comment: 63 pages, including 7 figures and Supporting Informatio
Chained activation of the motor system during language understanding
Two experiments were carried out to investigate whether and how one important characteristic of the motor system, that is its goal-directed organization in motor chains, is reflected in language processing. This possibility stems from the embodied theory of language, according to which the linguistic system re-uses the structures of the motor system. The participants were presented with nouns of common tools preceded by a pair of verbs expressing grasping or observational motor chains (i.e., grasp-to-move, grasp-to-use, look-at-to-grasp, and look-at-to-stare). They decided whether the tool mentioned in the sentence was the same as that displayed in a picture presented shortly after. A primacy of the grasp-to-use motor chain over the other motor chains in priming the participants' performance was observed in both the experiments. More interestingly, we found that the motor information evoked by the noun was modulated by the specific motor-chain expressed by the preceding verbs. Specifically, with the grasping chain aimed at using the tool, the functional motor information prevailed over the volumetric information, and vice versa with the grasping chain aimed at moving the tool (Experiment 2). Instead, the functional and volumetric information were balanced for those motor chains that comprise at least an observational act (Experiment 1). Overall our results are in keeping with the embodied theory of language and suggest that understanding sentences expressing an action directed toward a tool drives a chained activation of the motor system
Pseudospin Magnetism in Graphene
We predict that neutral graphene bilayers are pseudospin magnets in which the
charge density-contribution from each valley and spin spontaneously shifts to
one of the two layers. The band structure of this system is characterized by a
momentum-space vortex which is responsible for unusual competition between band
and kinetic energies leading to symmetry breaking in the vortex core. We
discuss the possibility of realizing a pseudospin version of ferromagnetic
metal spintronics in graphene bilayers based on hysteresis associated with this
broken symmetry.Comment: 5 pages, 4 figures; added figure 1, modified introduction and
discussion; updated reference
Fixed combination of lercanidipine and enalapril in the management of hypertension: focus on patient preference and adherence.
Hypertension is one of the most important and widespread risk factors for the development of cardiovascular disease. Once, combination therapy was traditionally reserved as a third-line or fourth-line approach in the management of hypertension. However, several major intervention trials in high-risk patient populations have shown that an average of 2-4 antihypertensive agents are required to achieve effective blood pressure control. Combination treatment should be considered as a first choice in patients at high cardiovascular risk and in individuals for whom blood pressure is markedly above the hypertension threshold (eg, more than 20 mmHg systolic or 10 mmHg diastolic), or when milder degrees of blood pressure elevation are associated with multiple risk factors, subclinical organ damage, diabetes, renal failure, or associated cardiovascular disease. A number of clinical trials have demonstrated that a fixed combination of lercanidipine and enalapril has better efficacy and tolerability than monotherapy with either agents. The fixed-dose formulation of lercanidipine-enalapril was well tolerated in all clinical trials, with an adverse event rate similar to that of the component drugs as monotherapy. The advantages of combination therapy include improved adherence to therapy and minimization of blood pressure variability. In addition, combining two antihypertensive agents with different mechanisms of action may provide greater protection against major cardiovascular events and the development of end-organ damage
High frequency electro-optic measurement of strained silicon racetrack resonators
The observation of the electro-optic effect in strained silicon waveguides
has been considered as a direct manifestation of an induced
non-linearity in the material. In this work, we perform high frequency
measurements on strained silicon racetrack resonators. Strain is controlled by
a mechanical deformation of the waveguide. It is shown that any optical
modulation vanishes independently of the applied strain when the applied
voltage varies much faster than the carrier effective lifetime, and that the DC
modulation is also largely independent of the applied strain. This demonstrates
that plasma carrier dispersion is responsible for the observed electro-optic
effect. After normalizing out free carrier effects, our results set an upper
limit of to the induced high-speed tensor
element at an applied stress of . This upper limit is about one
order of magnitude lower than the previously reported values for static
electro-optic measurements
Vitamin D Supplementation and COVID-19 Outcomes: Mounting Evidence and Fewer Doubts
The coronavirus disease 2019 (COVID-19) has already killed more than 6 million people around the world. A growing body of epidemiological evidence suggests that low 25-hydroxy vitamin D (25-OH-vitamin D) plasma levels are associated with an increased risk of developing COVID-19 and -most importantly-with a higher risk of developing more severe COVID-19 and dying. On the other hand, vitamin D supplementation during the early phases of COVID-19 has been related to a decreased length of hospital stay, less frequent need for oxygen, and a reduced mortality rate in inpatients. This seems to be particularly true when high dosages are used. In light of this evidence, further studies are needed to define the best timing for vitamin D supplementation and the most effective dosage schedule
An Evolving Definition of a “Healthy Diet”
Throughout life, most of us eat at least three meals a day for 365 days a year. It follows that, in a 90-year life, everyone is potentially exposed to food constituents (i.e., nutrients, bioactives, and other chemical compounds) more than 95 thousand times; therefore, dietary habits are a relevant determinant of health status.
In daily clinical practice, we usually discourage patients from eating foods deemed unhealthy, such as highly processed items. Even more rarely do we recommend that patients consume healthy foods, except as an alternative to junk foods. Nevertheless, it is well known that a healthy diet prevents several chronic and degenerative diseases and is the key to a healthy and long life. However, what is a healthy diet and how do we
define it? Recently, a large number of epidemiological studies have attempted to identify which dietary factors correlate with negative health outcomes, including death, loss of function, and lack of well-being. Determinants of positive health outcomes have been more rarely investigated, on the contrary
The Role of Electron-electron Interactions in Graphene ARPES Spectra
We report on a theoretical study of the influence of electron-electron
interactions on ARPES spectra in graphene that is based on the
random-phase-approximation and on graphene's massless Dirac equation continuum
model. We find that level repulsion between quasiparticle and plasmaron
resonances gives rise to a gap-like feature at small k. ARPES spectra are
sensitive to the electron-electron interaction coupling strength and might enable an experimental determination of this material parameter.Comment: 5 Pages, 4 Figures, Submitte
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