Search results for "RCA"
showing 10 items of 3171 documents
Molecular modeling of intercalation complexes of antitumor active 9-aminoacridine and a [d, e]-anellated isoquinoline derivative with base paired deo…
1996
Intercalators are molecules capable of sliding between DNA base pairs without breaking up the hydrogen bonds between the DNA bases. On the basis of molecular mechanics calculations structural, models of B-DNA tetranucleotide intercalation complexes of some cytostatic active 9-aminoacridines and of a [d, e]-anellated isoquinoline derivative are presented. The drug complexes are stabilized by energetically favouredvan der Waals interactions and by selective hydrogen bonds between the side chains of the drugs and the DNA bases. Semiempirical quantum chemistry calculations revealed that the chromophoric system of the intercalators is able to form π,π-charge-transfer interactions with the purine…
ChemInform Abstract: Pyrazolo[3,4-d][1,2,3]triazolo[1,5-a]pyrimidine: A New Ring System Through Dimroth Rearrangement.
2008
Abstract Derivatives of the new ring system pyrazolo[3,4- d ][1,2,3]triazolo[1,5- a ]pyrimidine were synthesized from the corresponding angular isomers, through a Dimroth rearrangement, in quantitative yields. Preliminary computational studies demonstrated that this class of compounds could be a good candidate as DNA intercalating agents.
Revealing interactions between polyaza pyridinophane compounds and DNA/RNA polynucleotides by SERS spectroscopy
2014
Surface-enhanced Raman scattering spectroscopy (SERS) in the near-infrared region had been applied to study interactions of polyaza pyridinophanes with single stranded RNA and double stranded DNA and RNA polynucleotides. Studied compounds, PYPOD and PHENPOD, differed in the central aromatic moiety, pyridine and phenanthroline, respectively, which linked two cyclic amines. An intense scattering was obtained from molecules adsorbed onto the silver nanoparticles, showing nonlinear concentration dependence in the 6.5 × 10−8−6.5 × 10−5 M range. New bands in spectra of PYPOD/polynucleotide and PHENPOD/polynucleotide mixtures were assigned to vibrational modes of polynucleotide moieties involved i…
Microscopic and nanoscopic EVA composite investigation: Electrical properties and effect of purification treatment
2004
This work presents preliminary results of an investigation aiming at characterization of nanocomposite insulating materials. Focus is made on size and technological process effects, i.e. dependence of electrical properties on filler size, on polymer-nanofiller interaction (e.g. intercalation or exfoliation) and, in particular, on chemical purification procedures. The materials under investigation are (EVA) copolymer filled by layered micro and nanosized silicates consisting of montmorillonite and fluorohectorite, that is, natural and synthetic clays. Microstructural characterization, using transmission electron microscopy, TEM, and wide-angle X-ray spectroscopy, WAXS, and electrical measure…
Hair Cortisol Concentration as a Biomarker of Sleep Quality and Related Disorders
2021
Cortisol is the end product of the hypothalamic-pituitary-adrenal (HPA) axis, and its production is increased mainly in stressful situations or in chronic disorders accompanied by stress enhancement. Altered cortisol concentrations have been reported in a number of neuropsychiatric diseases and sleep disorders. Cortisol concentrations have been measured using several methods, and in several matrixes, such as blood, saliva, and urine. However, lately, hair cortisol, for several reasons, has emerged as a promising biomarker of long-term retrospective HPA activation. Several experimental approaches for cortisol measurement with the corresponding concentration reference ranges and a summary of …
Sleep and Chronobiology as a Key to Understand Cluster Headache
2023
The cluster headache is a primary headache characterized by attacks of unilateral pain associated with ipsilateral cranial autonomic features. These attacks recur in clusters during the years alternating with periods of complete remission, and their onset is often during the night. This annual and nocturnal periodicity hides a strong and mysterious link among CH, sleep, chronobiology and circadian rhythm. Behind this relationship, there may be the influence of genetic components or of anatomical structures such as the hypothalamus, which are both involved in regulating the biological clock and contributing even to the periodicity of cluster headaches. The bidirectional relationship manifest…
Erenumab and Possible CGRP Effect on Chronotype in Chronic Migraine: A Real-Life Study of 12 Months Treatment
2023
The introduction of monoclonal antibodies (mAbs) directed against the calcitonin gene-related peptide (CGRP), or its receptor (CGRPr), revolutionized migraine management due to their high efficacy and few side effects. Data suggest that the CGRP may even be implicated in circadian rhythm, but studies about the effect of anti-CGRP treatments on sleep are still lacking. The aim of the present study was to assess the effect of erenumab (70 and 140 mg per month), a human mAb directed against CGRPr, on chronotype in chronic migraineurs; secondly, we assessed its efficacy, safety, and the effects on anxiety and depression. Sleep was evaluated using self-administrable questionnaires investigating …
Estudio de la relación entre los hábitos de vida, las variaciones del ritmo circadiano y los trastornos metabólicos en la obesidad infantil
2022
Numerosos estudios realizados en trabajadores del turno de noche evidencian una relación entre la alteración de los ritmos circadianos y los trastornos metabólicos. En paralelo, otras investigaciones realizadas principalmente en modelos animales o en adultos humanos, muestran una relación entre los hábitos de vida, la duración insuficiente y la mala calidad del sueño, y el desarrollo de la obesidad y sus comorbilidades. Sin embargo, se sabe poco sobre el papel que desempeñan estos mecanismos en la actual epidemia de obesidad infantil. Por ello, desarrollamos un estudio de la relación entre los hábitos de vida, los ritmos circadianos de la melatonina y el metabolismo, en el contexto de la ob…
Different moment, different tune : how emotional perception of music changes with the time of day
2012
According to the classical music tradition of Northern India, the ability of a song to induce certain emotions depends on the time of day: playing a song at the right time is said to maximise its emotional effect. Transposing this idea into a Western context, I decided to investigate this claim by combining findings in chronobiology with findings in music and emotion. It has already been established that our mood fluctuations follow a cyclical pattern. Besides, it is a known fact that our current mood influences our ability to perceive emotions. However, no one has ever linked these elements together and studied diurnal mood variations and their effect on perceived emotions in music. To tes…
Effects of daylight and artificial light on melatonin suppression in educational environment.
2012
An analysis of the characteristics of daylight in a scholastic environment was carried out by comparing SPDs and CCTs of the natural source (sky) during typical winter days with contemporaneous measurements of spectral irradiances and CCTs detected at the eyes level. Data obtained from these measurements together with those detected with artificial light, were used to evaluate the effects on melatonin suppression during the day according to the procedure proposed by Rea et al [2]. Despite illuminances on desks under natural and artificial light corresponded to the EN 12464-1 Standard requirements, the irradiances detected at eye's level, which are essential for melatonin suppression, do not…