Search results for "grain"
showing 10 items of 752 documents
Enhancement of the Performance of Perovskite Solar Cells, LEDs, and Optical Amplifiers by Anti-Solvent Additive Deposition
2016
The efficiency of perovskite optoelectronic devices is increased by a novel method; its suitability for perovskite solar cells, light-emitting diodes, and optical amplifiers is demonstrated. The method is based on the introduction of organic additives during the anti-solvent step in the perovskite thin-film deposition process. Additives passivate grain boundaries reducing non-radiative recombination. The method can be easily extended to other additives.
Optical experiments on a crystallizing hard-sphere–polymer mixture at coexistence
2010
We report on the crystallization kinetics in an entropically attractive colloidal system using a combination of time resolved scattering methods and microscopy. Hard sphere particles are polystyrene microgels swollen in a good solvent (radius a=380nm, starting volume fraction 0.534) with the short ranged attractions induced by the presence of short polymer chains (radius of gyration rg = 3nm, starting volume fraction 0.0224). After crystallization, stacking faulted face centred cubic crystals coexist with about 5% of melt remaining in the grain boundaries. From the Bragg scattering signal we infer the amount of crystalline material, the average crystallite size and the number density of cry…
Rizatriptan in the treatment of migraine.
2006
Migraine is a common, disabling disorder associated with considerable personal and societal burden. Current guidelines recommend triptans for the acute treatment of migraine unlikely to respond to less effective therapies. Rizatriptan is a second-generation triptan available in tablet or orally disintegrating tablet (wafer) formulations that offers several advantages over other members of its class. Rizatriptan is rapidly absorbed from the gastrointestinal tract and achieves maximum plasma concentrations more quickly than other triptans, providing rapid pain relief. Clinical trials have shown that rizatriptan is at least as effective or superior to other oral migraine-specific agents in the…
Two-dimensional apparent microfabric of the basal Late Weichselian till and associated shear zone: case study from western Latvia
2008
The examination of glacial sediments in thin sections has become a common procedure in recent years. Apparent sand grain orientation (microfabric) in thin sections is one of the key elements marking certain microstructures. In an attempt to make till micromorphology studies less subjective and investigate the orientation of sand-sized particles in tills, we have developed an image analysis procedure to measure and analyse the spatial distribution of the till microfabric. We studied 13 thin sections of the Weichselian subglacial till and basal shear zone outcropping in the Baltic Sea bluffs at the Ziemupe site in western Latvia. The results were visualized as a two-dimensional grid of rose d…
Interaction of somatoform and vestibular disorders
2006
The high coincidence of organic vestibular and somatoform vertigo syndromes has appeared to support pathogenic models showing a strong linkage between them. It was hypothesised that a persisting vestibular dysfunction causes the development of anxiety disorders.To determine the relation between vestibular deficits and somatoform vertigo disorders in an interdisciplinary prospective study.Participants were divided into eight diagnostic groups: healthy volunteers (n=26) and patients with benign paroxysmal positioning vertigo (BPPV, n=11), vestibular neuritis (n=11), Menière's disease (n=7), vestibular migraine (n=15), anxiety (n=23), depression (n=12), or somatoform disorders (n=22). Neuro-ot…
ESR observations of paramagnetic centers in intrinsic hydrogenated microcrystalline silicon
2002
Paramagnetic centers in hydrogenated microcrystalline silicon, mc-Si:H have been studied using dark and light-induced electron-spin resonance ~ESR!. In dark ESR measurements only one center is observed. The g values obtained empirically from powder-pattern line-shape simulations are gi52.0096 and g’52.0031. We suggest that this center may be due to defects in the crystalline phase. During illumination at low temperatures, an additional ESR signal appears. This signal is best described by two powder patterns indicating the presence of two centers. One center is asymmetric (gi51.999, g’51.996), while the other is characterized by large, unresolved broadening such that unique g values cannot b…
Prevalence of red ear syndrome in juvenile primary headaches.
2010
Background: Previous studies have suggested a relationship between ‘red ear syndrome’ (RES) and pediatric migraine. Aims of this study were (i) to assess the frequency, specificity and sensitivity of RES in a population of pediatric migraineurs and (ii) to establish the pathophysiological mechanisms of RES associated with migraine. Methods and results: A total of 226 children suffering from headache (aged 4–17 years) were enrolled. One hundred and seventy-two (76.4%) were affected by migraine, the remaining 54 (23.6%) by other primary headaches. RES was followed significantly more frequently by migraine (23.3%; p < .0001), and was characterized by high specificity and positive predictiv…
Pediatric Chronic Migraine Severity and Maternal Stress
2021
Primary headache is an increasing phenomenon in pediatric age, and very often, it causes disabling limitations in children’s daily activities, negatively affecting family well-being. There are conflicting data in the literature on the impact of children’s migraines on parental experienced stress. This study aimed to evaluate maternal stress in a sample of school-aged children with a migraine without aura (MwoA) and its correlation with migraine intensity and frequency. A total of 474 mothers aged between 31 and 55 participated in the study: 237 were mothers of children with MwoA, and 237 were mothers of typical developing children. All participants were administered the Parent Stress Index-…
NREM Sleep Instability in Pediatric Migraine Without Aura
2019
Children with migraine headaches appear to have a range of sleep disturbances. The aim of the present study was to assess the NREM sleep instability in a population of school-aged individuals affected by migraine without aura (MoA). Thirty-three children with MoA (20 males, 13 females, mean age 10.45 ± 2.06 years) underwent to overnight Polysomnographic (PSG) recordings and Cyclic Alternating Pattern (CAP) analyses accordingly with international criteria. MoA group showed a reduction in sleep duration parameters (TIB, SPT, TST; p ≤ 0.001 for all) and in arousal index during REM sleep and an increase in awakenings per hour (AWK/h) vs. Controls (C) (p = 0.008). In particular, MoA children sho…
P072. The visual cortical excitability in pediatric migraine as tested by sound-induced flash illusions
2015
Objectives Sound-induced flash illusions (SIFI) depend on visual cortex (V1) excitability [1]. In adults with migraine, in response to visual-acoustic illusions, V1 is hyperexcitable [2]. Susceptibility to SIFI is increased in children than adults. During childhood there is a change in sensory dominance: acoustic dominant switching to a visual [3]. Here we used SIFI to evaluate V1 excitability in children with migraine assessing also age-related differences in cross-modal audio-visual perception.