120 research outputs found
E-learning as a university challenge of the 21st century
The article is one of several articles summarizing research carried out with a group of foreign students who come to Poland to participate in the Erasmus+ program. Method and research group: Research has been taking place since 2016 and is conducted using an interactive Google survey. The study group consists of 128 people aged 18 to 25 years. The respondents chose Poland, specifically the Maria Curie-Skłodowska University, in order to complete a semester or an academic year. This article will also present structured interviews that were conducted with foreign students. Aim of the study: To learn about the attitude of foreign students towards modern teaching methods (e-learning). An additional goal was to verify the knowledge regarding this method of education and to compare Poland with the respondents’ home countries. Results: The respondents come from European countries such as Spain, Portugal, Germany, France, as well as, Braziland India. Most of them appreciate the possibilities of e-learning (87%). Over half of the respondents (62%) say that in Poland distance learning was rather not implemented until 2020. What changed this situation was the coronavirus outbreak. In social sciences, they also appreciate the possibility of classes in the traditional form due to the possibility of participating in workshops and specialist training, or giving presentations.The article is one of several articles summarizing research carried out with a group of foreign students who come to Poland to participate in the Erasmus+ program. Method and research group: Research has been taking place since 2016 and is conducted using an interactive Google survey. The study group consists of 128 people aged 18 to 25 years. The respondents chose Poland, specifically the Maria Curie-Skłodowska University, in order to complete a semester or an academic year. This article will also present structured interviews that were conducted with foreign students. Aim of the study: To learn about the attitude of foreign students towards modern teaching methods (e-learning). An additional goal was to verify the knowledge regarding this method of education and to compare Poland with the respondents’ home countries. Results: The respondents come from European countries such as Spain, Portugal, Germany, France, as well as, Braziland India. Most of them appreciate the possibilities of e-learning (87%). Over half of the respondents (62%) say that in Poland distance learning was rather not implemented until 2020. What changed this situation was the coronavirus outbreak. In social sciences, they also appreciate the possibility of classes in the traditional form due to the possibility of participating in workshops and specialist training, or giving presentations
First-principles simulations of the initial phase of self-aggregation of a cyanine dye: structure and optical spectra
Using first-principles simulations, we investigated the initial steps of the self-aggregation of the dye pseudoisocyanine (PIC) in water. First, we performed molecular dynamics (MD) simulations of the self-aggregation process, in which pile-of-coins oligomers ranging from dimers to stacks of about 20 molecules formed. The oligomer structures were found to be very flexible, with the dimers entering a weakly coupled state and then returning to a stable π-π stacked conformation on a nanosecond time scale. The structural information from the MD simulations was combined with quantum chemical calculations to generate a time-dependent Frenkel exciton Hamiltonian for monomers, dimers, and trimers, which included vibronic coupling. This Hamiltonian, in turn, was used to calculate the absorption spectra for these systems. The simulated dimer spectrum compared well to experiment, validating the face-to-face stacked dimer arrangement found in our MD simulations. Comparison of the simulated trimer spectrum to experiment suggested that oligomers larger than the dimer cannot be abundant at the onset of J-aggregation. Finally, the conformation of the PIC J-aggregate was investigated by testing the stability of several possible conformations in our MD simulations; none of the tested structures was found to be stable
Polariton effects in molecular crystals studied by classical and quantum-electrodynamic approaches
A quantum-electrodynamic approach is studied as an alternative to the
classical description of polaritons in molecular crystals, with the focus on
future interpretation of oligothiophene spectra. As expected, the results of
the two approaches coincide, but the quantum description is better suited
for future generalizations, notably for detailed studies of vibronic coupling.
The quantum approach is used here to probe the importance of inherent
polaritonic effects. They are found to be minor, being superseded by vibronic
interactions; the latter are responsible for most peculiarities observed in
oligothiophene spectra
The analysis of solidification process of ferritic-austenitic cast steel
Abstract One of the most common defects leading to the rejection of faulty castings made of duplex cast steel is hot cracking. Hot crackingdifferently from cold cracking which occur on cooling, when the material exhibits already distinct elastic properties -proceeds in the semi-solid state, particularly when the temperature of solidifying casting is close to the equilibrium solidus point. There exist a range of temperatures in the vicinity of the solidus point within which the solidifying metal shows very small deformation ability and small strength. Therefore even little stresses occurring at the solidification stage and caused by density difference between ferrite and austenite, or restricted shrinkage, or various temperature gradients, can be the reason of hot cracking. Copper addition, as it is used in cast steel grades implemented in Polish power industry applications, decreases the temperature of the end of solidification, thus affecting beneficially the surface reproduction quality, but on the other hand it can promote, along with several other elements contained in duplex cast steel, the peritectic transformation during the last stage of solidification. The presence of peritectic solidification, i.e. strictly speaking the structural stresses accompanying that process, is the well-known and significant reason of the increased steel defectiveness in the continuous steel casting (CSC) technology if the steel with carbon content promoting the peritectic transformation is processed. The authors have presented the examination results of the solidification phenomenon for two duplex cast steel grades -one without copper addition, and the other with addition of about 3.0% Cu
Styl życia i wyrównanie metaboliczne u pacjentów z cukrzycą typu 2 a ryzyko powikłań przewlekłych tej choroby
Wstęp. Źle kontrolowana cukrzyca prowadzi do narządowych powikłań tej choroby. Ważnym elementem w zapobieganiu tym powikłaniom jest zmiana stylu życia. Poprzez należyte wyrównanie metaboliczne u chorych na cukrzycę typu 2, u których powikłania już się rozwinęły, można spowolnić ich progresję oraz zapobiec rozwojowi dalszych powikłań. Celem pracy była ocena wpływu stylu życia na wyrównanie metaboliczne cukrzycy oraz na powikłania przewlekłe. Materiał i metody. Badaniem objęto grupę 206 chorych na cukrzycę typu 2 w wieku 30–66 lat i starszych, z czasem trwania choroby do 5 lat. Ostatecznie analizie poddano 183 kompletnie wypełnione kwestionariusze. W przedstawionej pracy jako metodę badawczą zastosowano sondaż diagnostyczny z wykorzystaniem autorskiego kwestionariusza oraz analizę dokumentacji medycznej. Wyniki. Przeprowadzona analiza wyników wykazała, że żaden z pacjentów nie spełniał wszystkich parametrów wyrównania metabolicznego. Zmianę stylu życia po rozpoznaniu cukrzycy deklarowało 86,5% badanych, jednak nie przekładało się to obraz kliniczny choroby ani rzeczywiste nawyki żywieniowe. W badanej grupie występowały powikłania cukrzycowe, które częściej dotyczyły kobiet (55,8%). Najczęstszym powikłaniem była neuropatia. Wnioski. Wiedza respondentów na temat choroby nie jest wykorzystywana w praktyce i nie przekłada się na ich styl życia. Poziom wyrównania cukrzycy wśród badanej populacji nie zależy istotnie od aktywności zawodowej, natomiast w niewielkim stopniu jest zależny od ich zachowań zdrowotnych. Brak wyrównania metabolicznego w cukrzycy skutkuje rozwojem powikłań u badanych
Clinical and neuropathological picture of familial encephalopathy with bifunctional protein deficiency
Peroxisomal diseases are a heterogeneous group of genetic metabolic disorders which are caused by incorrect
biogenesis of peroxisomes or a defect in activity of particular enzymes located in those organelles.
D-bifunctional protein (D-BP) deficiency belongs to the second group of peroxisomal diseases characterised by
dysfunction of a single peroxisomal enzyme. Bifunctional protein is a catalyst in the second and third stage of the
\beta-oxidation of fatty acids. Gene locus of bifunctional protein deficiency comprises chromosomes 5q2 and 3p23-p22.
The authors present two siblings with progressing family encephalopathy. In the younger brother the diagnosis of
a bifunctional protein deficiency was made. The girl died before a diagnosis was made; however, due to the presence
of a very similar clinical condition a suspicion arises that the girl had a peroxisomal disease. In the siblings were
ascertained characteristic dysmorphic features, delayed psychomotor development, polymorphic epileptic seizures
and generalized muscular hypotonia with areflexia.
The neuropathological findings were consistent in general with MRI findings showing features of hypomyelination.
Also neuron heterotopias that were found in autopsy are a form of pathology typical for D-BP
Exciton level structure and dynamics in tubular porphyrin aggregates
We present an account of the optical properties of the Frenkel excitons in self-assembled porphyrin tubular aggregates that represent an analog to natural photosynthetic antennae. Using a combination of ultrafast optical spectroscopy and stochastic exciton modeling, we address both linear and nonlinear exciton absorption, relaxation pathways, and the role of disorder. The static disorder-dominated absorption and fluorescence line widths show little temperature dependence for the lowest excitons (Q band), which we successfully simulate using a model of exciton scattering on acoustic phonons in the host matrix. Temperature-dependent transient absorption of and fluorescence from the excitons in the tubular aggregates are marked by nonexponential decays with time scales ranging from a few picoseconds to a few nanoseconds, reflecting complex relaxation mechanisms. Combined experimental and theoretical investigations indicate that nonradiative pathways induced by traps and defects dominate the relaxation of excitons in the tubular aggregates. We model the pump?probe spectra and ascribe the excited-state absorption to transitions from one-exciton states to a manifold of mixed one- and two-exciton states. Our results demonstrate that while the delocalized Frenkel excitons (over 208 (1036) molecules for the optically dominant excitons in the Q (B) band) resulting from strong intermolecular coupling in these aggregates could potentially facilitate efficient energy transfer, fast relaxation due to defects and disorder probably present a major limitation for exciton transport over large distances. We present an account of the optical properties of the Frenkel excitons in self-assembled porphyrin tubular aggregates that represent an analog to natural photosynthetic antennae. Using a combination of ultrafast optical spectroscopy and stochastic exciton modeling, we address both linear and nonlinear exciton absorption, relaxation pathways, and the role of disorder. The static disorder-dominated absorption and fluorescence line widths show little temperature dependence for the lowest excitons (Q band), which we successfully simulate using a model of exciton scattering on acoustic phonons in the host matrix. Temperature-dependent transient absorption of and fluorescence from the excitons in the tubular aggregates are marked by nonexponential decays with time scales ranging from a few picoseconds to a few nanoseconds, reflecting complex relaxation mechanisms. Combined experimental and theoretical investigations indicate that nonradiative pathways induced by traps and defects dominate the relaxation of excitons in the tubular aggregates. We model the pump?probe spectra and ascribe the excited-state absorption to transitions from one-exciton states to a manifold of mixed one- and two-exciton states. Our results demonstrate that while the delocalized Frenkel excitons (over 208 (1036) molecules for the optically dominant excitons in the Q (B) band) resulting from strong intermolecular coupling in these aggregates could potentially facilitate efficient energy transfer, fast relaxation due to defects and disorder probably present a major limitation for exciton transport over large distances
Promotion of men’s mental health
Introduction: Despite the fact that the knowledge of health differences between males and females is more and more
available, it does not always translate into the differentiation of health programmes. Undoubtedly, there is a need for
innovative programmes promoting the mental health of men and accounting for male standards.
Material and methods: Review of scientific literature concerning mental health promotion, with special regard to
recommendation to create programmes of promotion of men’s mental health searched in Pubmed, Scopus and Google
Scholar.
Results: Health promotion is a process enabling people to increase their control over health and to improve it. Mental
health promotion is a rarely discussed branch of health promotion, and its characteristics differ from physical health
promotion. Currently, no organised activities are conducted in Poland aiming at the promotion of men’s mental health.
Looking at suicide statistics, according to which men take their lives seven times more often than women, it seems essential
to design comprehensive activities targeting this specific group. Male-specific determinants of mental health should
constitute a reference point for health promoters in the process of designing programmes of mental health promotion.
Conclusions: It seems necessary to consider gender factor while designing activities related to mental health promotion.
The activities directed to men should be planned according to specific principles. Their implementation may have
a positive effect on male participation and involvement in the suggested programme of mental health promotion, and
in turn on its efficacy.Introduction: Despite the fact that the knowledge of health differences between males and females is more and more available, it does not always translate into the differentiation of health programmes. Undoubtedly, there is a need for innovative programmes promoting the mental health of men and accounting for male standards. Material and methods: Review of scientific literature concerning mental health promotion, with special regard to recommendation to create programmes of promotion of men’s mental health searched in Pubmed, Scopus and Google Scholar. Results: Health promotion is a process enabling people to increase their control over health and to improve it. Mental health promotion is a rarely discussed branch of health promotion, and its characteristics differ from physical health promotion. Currently, no organised activities are conducted in Poland aiming at the promotion of men’s mental health. Looking at suicide statistics, according to which men take their lives seven times more often than women, it seems essential to design comprehensive activities targeting this specific group. Male-specific determinants of mental health should constitute a reference point for health promoters in the process of designing programmes of mental health promotion. Conclusions: It seems necessary to consider gender factor while designing activities related to mental health promotion. The activities directed to men should be planned according to specific principles. Their implementation may have a positive effect on male participation and involvement in the suggested programme of mental health promotion, and in turn on its efficacy
Erythropoietin enhances hippocampal long-term potentiation and memory
<p>Abstract</p> <p>Background</p> <p>Erythropoietin (EPO) improves cognition of human subjects in the clinical setting by as yet unknown mechanisms. We developed a mouse model of robust cognitive improvement by EPO to obtain the first clues of how EPO influences cognition, and how it may act on hippocampal neurons to modulate plasticity.</p> <p>Results</p> <p>We show here that a 3-week treatment of young mice with EPO enhances long-term potentiation (LTP), a cellular correlate of learning processes in the CA1 region of the hippocampus. This treatment concomitantly alters short-term synaptic plasticity and synaptic transmission, shifting the balance of excitatory and inhibitory activity. These effects are accompanied by an improvement of hippocampus dependent memory, persisting for 3 weeks after termination of EPO injections, and are independent of changes in hematocrit. Networks of EPO-treated primary hippocampal neurons develop lower overall spiking activity but enhanced bursting in discrete neuronal assemblies. At the level of developing single neurons, EPO treatment reduces the typical increase in excitatory synaptic transmission without changing the number of synaptic boutons, consistent with prolonged functional silencing of synapses.</p> <p>Conclusion</p> <p>We conclude that EPO improves hippocampus dependent memory by modulating plasticity, synaptic connectivity and activity of memory-related neuronal networks. These mechanisms of action of EPO have to be further exploited for treating neuropsychiatric diseases.</p
The effect of intermolecular interaction on excited states in p − DTS(FBTTH 2
Using optical spectroscopy in solution and thin film, and supported by quantum chemical calculations, we investigated the aggregation process of the donor-acceptor type molecule p − DTS(FBTTH2)2. We demonstrate that cooling a solution induces a disorder-order phase transition that proceeds in three stages analogous to the steps observed in semi-rigid conjugated polymers. By analyzing the spectra, we are able to identify the spectral signature of monomer and aggregate in absorption and emission. From this we find that in films, the fraction of aggregates is near 100% which is in contrast to films made from semi-rigid conjugated polymers
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