Search results for "Valence"
showing 10 items of 2732 documents
Use of Caffeine for Cognitive Enhancement
2015
Abstract Pharmacological cognitive enhancement (CE) refers to the use of divergent psychoactive substances with the purpose of enhancing one's own cognition (e.g., increasing vigilance, concentration, memory). The group of substances for CE includes divergent over-the-counter drugs. Caffeine-containing products such as coffee, caffeinated drinks, and caffeine tablets are integral part of this group of substances. Furthermore, prescription drugs as well as illicit drugs belong to this group of CE substances (e.g., [psycho-]stimulants, modafinil). The use of caffeine in normal healthy subjects has very limited procognitive effects. However, there are few procognitive effects in healthy but sl…
Prevalence and factors associated with circadian blood pressure patterns in hypertensive patients.
2009
Comment in Timing of antihypertensive therapy and circadian blood pressure pattern. [Hypertension. 2009] Timing of antihypertensive therapy and circadian blood pressure pattern. Almirall J, Martínez-Ocaña JC, Comas L. Hypertension. 2009 Jun; 53(6):e41; author reply e42. Epub 2009 May 4. Dipping comes of age: the importance of nocturnal blood pressure. [Hypertension. 2009]. Dipping comes of age: the importance of nocturnal blood pressure. O'Brien E. Hypertension. 2009 Mar; 53(3):446-7. Epub 2009 Jan 26.Nondipping in patients with hypertension. [Hypertension. 2009] Ambulatory blood pressure (BP) monitoring has become useful in the diagnosis and management of hypertensive individuals. In addit…
Lifestyle and impact on cardiovascular risk factor control in coronary patients across 27 countries: Results from the European Society of Cardiology …
2019
Aims The aim of this study was to determine whether the Joint European Societies guidelines on secondary cardiovascular prevention are followed in everyday practice. Design A cross-sectional ESC-EORP survey (EUROASPIRE V) at 131 centres in 81 regions in 27 countries. Methods Patients (<80 years old) with verified coronary artery events or interventions were interviewed and examined ≥6 months later. Results A total of 8261 patients (females 26%) were interviewed. Nineteen per cent smoked and 55% of them were persistent smokers, 38% were obese (body mass index ≥30 kg/m2), 59% were centrally obese (waist circumference: men ≥102 cm; women ≥88 cm) while 66% were physically active <30 min 5…
PREVALENCE OF ARTERIAL HYPERTENSION AND CHARACTERISTICS OF NOCTURNAL BLOOD PRESSURE PROFILE OF ASTHMA PATIENTS ACCORDING TO THERAPY AND SEVERITY OF T…
2020
Background: several studies report an increased risk for asthmatic subjects to develop arterial hypertension and the relationship between these two diseases, frequently co-existing, still has some unclear aspects. Methods: The BADA (blood pressure levels, clinical features and markers of subclinical cardiovascular damage of asthma patients) study is aimed to evaluate the prevalence of the cardiovascular comorbidities of asthma and their impact on the clinical outcome. The main exclusion criteria were the presence of other respiratory diseases, current smoking, any contraindication to ambulatory blood pressure monitoring (ABPM). Results: The overall percentage of asthmatics having also hyper…
Caries Severity, Decayed First Permanent Molars and Associated Factors in 6-7 Years Old Schoolchildren Living in Palermo (Southern Italy).
2023
To date, there are very few epidemiologic studies on caries disease in 6–7 year old children living in Sicily (Southern Italy). The first permanent molar (FPM) is the most commonly affected tooth in this target population, and a one-unit increase in the number of decayed FPMs is predictive of caries in other teeth and in adulthood. The primary aim of this research is to estimate the prevalence of caries in 6–7 year old schoolchildren living in Palermo and, as a secondary aim, to estimate the prevalence of affected FPMs. It was designed as a cluster cross-sectional survey on 995 children from 16 schools, selected based on their geographical location, in one of the eight city districts. Carie…
Theoretical study of asymmetrically substituted poly(organosilanes)
1994
Summary form only given. Poly(organosilanes) [-SiRR'-] where R and R' represent various alkyl and aryl groups, are the subject of intense scientific and technological interest because of the interesting properties such as, intense near-UV absorption, highly efficient photoluminiscence, non-linear optical properties, these polymers present. In this contribution, we present the electronic structure of some asymmetrically substituted poly(organositanes). We have focused the study on the effect of the tacticity on the electronic structure of the polymer. We have employed ab initio methods to obtain reliable geometrical parameters. The band structure calculations have been performed using the va…
Non linear viscoelasticity of polymeric liquids interpreted by means of a stress dependence of free volume
1977
Several existing data of non-linear viscoelasticity of amorphous polymers aboveT g are here interpreted by assuming that the free volume changes during the motion. Equations of a stress-temperature equivalence are suggested which favorably compare with the data. It is also shown that the volume variations are sufficiently small to have escaped observation.
Spin crossover in soft matter
2014
Abstract This review article is devoted to the study of the spin crossover phenomenon in soft matter. Spin crossover compounds, though known for decades, bear the potential for practical applications in switching, sensing and display devices. Having arrived at a reasonable understanding of the spin transition process in solid and liquid states, one trend in this research field is to extend the knowledge into soft matter. The review begins with a brief description of Langmuir–Blodgett thin films based on FeII coordination compounds since it represents the first study of the spin crossover phenomenon in soft matter. The following section illustrates the FeII, FeIII and CoII complexes reported…
Electronic structure of polysilanes: influence of substitution and conformation
1993
Abstract The valence effective Hamiltonian (VEH) quantum-chemical approach is used to investigate the electronic properties of polysilane. The valence band structure calculated for this fully saturated polymer is analyzed in terms of orbital contributions and compared to that of the closely related carbon polymer, polyethylene. The effects of alkyl substitution and silicon backbone conformation are studied by elucidating the modifications that these structural changes induce on the electronic valence band structure of all-trans unsubstituted polysilane. The VEH results predict a decrease of the band gap upon alkyl substitution and on going from helical to all-trans conformations.
ChemInform Abstract: Benzoxetes and Benzothietes - Heterocyclic Analogues of Benzocyclobutene
2012
Benzo-condensed four-ring heterocycles, such as benzoxetes 1 and benzothietes 3 represent multi-purpose starting compounds for the preparation of various higher heterocyclic ring systems. The thermal or photochemical valence isomerizations between the benzenoid forms 1,3 and the higher reactive o-quinoid structures 2,4 provide the basis for the synthetic applications. On the other hand, this valence isomerization impedes in particular the generation and storage of 1 because the thermal equilibrium 1 2 is completely on the side of 2. Thus, the number of erroneous or questionable benzoxete structures published to date is surprisingly high. On the contrary, the thermal equilibrium 3 4 is on th…