Nutrient Status in Patients with Frequent Episodic Tension-Type Headache: A Case-Control Study

Objective: To investigate the relationship between frequent episodic tension-type headache (FE-TTH) and 25-hydroxyvitamin-D (25(OH)D), folate, vitamin B12, and magnesium. Design-Methods: A prospective case-control study involving adults with FETTH and age-sex matched healthy controls (HC) was performed. Individuals under the responsibility of the three provincial Health Centres of the prefecture of Trikala (Central Greece) were recruited during their regular check-up visits. The relationship between FETTH and serum levels of 25(OH)D, vitamin B12, folate, and magnesium was investigated (primary outcomes). Demographics, daily habits, somatometrics, psychometric and sleep quality measurements, laboratory indices, cardiovascular comorbidities and medications taken were also recorded and compared (secondary outcomes). Potential associations of the above-listed parameters with headache parameters (headache frequency, severity and analgesic consumption) were also examined (secondary outcomes). Results: Between September and December 2020, 30 patients with FETTH and 30 HC were successfully recruited. Demographics, comorbidities, regular medications, smoking habits, alcohol and coffee consumption, body mass index measurements, markers of systemic inflammation, folate and vitamin B12 levels were similar between the two groups (P > 0.05). Lower serum 25(OH)D was both univariately (P < 0.001) and multivariately [OR= 0.72, 95%CI = (0.55, 0.94) per 1 ng/ml increase] associated with FETTH, while serum magnesium was found lower in FETTH only according to the univariate approach (P = 0.036). Higher levels of depression (P = 0.050) and anxiety (P = 0.020), as well as poor quality of sleep (P = 0.008), were univariately associated with FETTH. Only the effect of anxiety remained significant following the multivariate logistic regression [OR= 7.90, 95%CI = (1.00, 62.47)]. Headache parameters were not associated with any one of the assessed variables. Discussion: Lower serum 25(OH)D was related to the presence of FETTH. This finding could imply a potential role for vitamin D in the pathophysiology of TTH. © 2021 Elsevier Masson SA

Order, viscoelastic, and dielectric properties of symmetric and asymmetric alkyl[1]benzothieno[3,2-b][1]benzothiophenes

The morphology, the viscoelastic, the dielectric properties and the dynamics of phase transformation are studied in symmetrically and asymmetrically substituted alkyl[1]benzothieno[3,2-b][1]benzothiophenes (C8-BTBT) by X-ray scattering, rheology, and dielectric spectroscopy. The interlayer spacing reflects the molecular and supramolecular ordering, respectively, in the symmetrically and asymmetrically substituted BTBTs. In the asymmetric BTBT, the core layer is double in size with a broader network of intermolecular interactions though the increased S-S contacts that is prerequisite for the development of high performance OFET devices. Two crystal states with elastic and viscoelastic responses were identified in the symmetric compound. In contrast, the SmA phase in the asymmetric compound is a viscoelastic solid. A path-dependent dielectric environment with a switchable dielectric permittivity was found in both compounds by cooling below 0 C with possible implications to charge transport. The kinetics of phase transformation to the crystalline and SmA phases revealed a nucleation and growth mechanism with rates dominated by the low activation barriers. © 2014 American Chemical Society.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

A phenomenographic study of Greek primary school students' representations concerning technology in daily life

The present research investigated and studied students' representations about daily life technologies, in a prospect of studying technology in Greek primary education. In the research participated 60 Greek primary school students aged 9 to 12 years old. Research data were collected through semi-structured, personal, clinical-type interviews. Each interview investigated student's conceptions and views about the following thematic areas: the concept of technology, daily life technologies, technological change, and the impact of technology use in everyday life. Data analysis revealed that the majority of students equated technology with modern tools and appliances, especially with computers, TV, mobile phones, satellites and other micro- and macro-technologies, whereas experience based technologies (de Vries, Technology education: Beyond the "technology is applied science" paradigm. J. Technol. Edu. 8 (1996), 7) have been hardly recognized by them as technology. Also students' representations can be categorized either as technology-oriented representations, which focus on a collection of technical means without reference to humans, or as human-oriented representations, focused on technical means with substantial reference to human needs and activities. Depending on these types of representations, students seem to conceive differently the nature of the problems, which they recognize that the wide use of technology causes mainly to the environment and the responsibility of the user for these problems. Moreover, it seems that the concept of technological change is a quite difficult one for the students. In order to help students form adequate representations about daily life technology and technological change an appropriate teaching approach was designed on the basis of these students' representations

Self-assembly of polyhedral metal–organic framework particles into three-dimensional ordered superstructures

Self-assembly of particles into long-range, three-dimensional, ordered superstructures is crucial for the design of a variety of materials, including plasmonic sensing materials, energy or gas storage systems, catalysts and photonic crystals. Here, we have combined experimental and simulation data to show that truncated rhombic dodecahedral particles of the metal–organic framework (MOF) ZIF-8 can self-assemble into millimetre-sized superstructures with an underlying threedimensional rhombohedral lattice that behave as photonic crystals. Those superstructures feature a photonic bandgap that can be tuned by controlling the size of the ZIF-8 particles and is also responsive to the adsorption of guest substances in the micropores of the ZIF-8 particles. In addition, superstructures with different lattices can also be assembled by tuning the truncation of ZIF-8 particles, or by using octahedral UiO-66 MOF particles instead. These well-ordered, submicrometre-sized superstructures might ultimately facilitate the design of three-dimensional photonic materials for applications in sensing

Elucidating the impact of molecular packing and device architecture on the performance of nanostructured perylene diimide solar cells

The performance of organic photovoltaic devices (OPV) with nanostructured polymer:perylene diimide (PDI) photoactive layers approaches the levels of the corresponding polymer:fullerene systems. Nevertheless, a coherent understanding of the difficulty for PDI-based OPV devices to deliver high power conversion efficiencies remains elusive. Here we perform a comparative study of a set of four different polymer:PDI OPV model systems. The different device performances observed are attributed to differences in the nanostructural motif of these composites, as determined by wide-angle X-ray scattering (WAXS) measurements. Long-range structural order in the PDI domain dictates (i) the stabilization energy and (ii) the concentration of the PDI excimers in the composites. The quenching of the PDI excimer photoluminescence (PL) is found to be insensitive to the former, but it depends on the latter. High PL quenching occurs for the low concentration of PDI excimers that are formed in PDI columns with a length comparable to the PDI excimer diffusion length. The stabilization of the PDI excimer state increases as the long-range order in the PDI domains improves. The structural order of the PDI domains primarily affects charge transport. Electron mobility reduces as the size of the PDI domain increases, suggesting that well-ordered PDI domains suffer from poor electronic connectivity. WAXS further reveals the presence of additional intermolecular PDI interactions, other than the direct face-to-face intermolecular coupling, that introduce a substantial energetic disorder in the polymer:PDI composites. Conventional device architectures with hole-collecting ITO/PEDOT:PSS bottom electrodes are compared with inverted device architectures bearing bottom electron-collecting electrodes of ITO/ZnO. In all cases the ZnO-functionalized devices surpass the performance of the conventional device analogues. X-ray photoelectron spectroscopy explains that in PEDOT:PSS-functionalized devices, the PDI component preferentially segregates closer to the hydrophilic PEDOT:PSS electrode, thus impeding the efficient charge extraction and limiting device photocurrent