Prague, Czech Republic
Prague, Czech Republic

Charles University in Prague is the oldest and largest university in the Czech Republic. Founded in 1348, it was the first university in Central Europe, east of France and north of the Alps. It is one of the oldest universities in Europe in continuous operation and ranks in the upper 1.5 percent of the world’s best universities.Its seal shows its protector Emperor Charles IV, with his coats of arms as King of the Romans and King of Bohemia, kneeling in front of St. Wenceslas, the patron saint of Bohemia. It is surrounded by the inscription, Sigillum Universitatis Scolarium Studii Pragensis . Wikipedia.

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Charles University | Date: 2017-05-17

A testing thermo-chamber, which is equipped with a bearing (1), heat exchanger (2) and a tension bar (4) for attaching the tested object. The inner room of the bearing ( 1 ) is equipped with a temperature sensor ( 3 ), the heat exchanger (2) being connected to more heating and cooling circuits (6) with multiport control valves (9), interconnected to thermostats (10) and by-passing branches (11), temperature sensor (3) is connected to the temperature regulator (12 ) further connected to thermostats (10) and a control unit (13) interconnected with multiport control valves (9).

News Article | April 17, 2017

People with Parkinson’s disease may show hints of motor difficulty years before an official diagnosis, but current methods for detecting early symptoms require clinic visits and highly trained personnel. Three recent studies, however, suggest that diagnosis could be as simple as walking, talking and typing. Tests of activities such as these might eventually enable early intervention, which will be crucial for halting progression of the neurodegenerative condition if a cure becomes available. The findings are exciting, says neurologist Zoltan Mari of Johns Hopkins University. But he cautions that larger studies will be necessary to ensure that these techniques are ready for wider use. Walking: Data from wearable sensors attached to 93 Parkinson’s patients and 73 healthy controls revealed distinctive walking patterns: factors such as step distance and heel force helped to differentiate between the two groups with 87 percent accuracy, according to an analysis by Shyam Perumal and Ravi Sankar of the University of South Florida. Talking: In a study by Jan Rusz of Czech Technical University and Charles University, both in Prague, and his colleagues, participants read a list of words aloud, and each made a 90-second recording during which they described their current interests. Fifty of the participants were at high risk for developing Parkinson’s, but only 23 had begun to show symptoms. Simple acoustic features of the short speech samples—including slower speed of talking and longer duration of pauses than healthy controls—pinpointed the symptomatic participants with 70 percent accuracy. Typing: People with and without Parkinson’s were asked to listen to a folktale and transcribe it by typing. The two groups were matched for age and overall typing speed and excluded people with dementia. Luca Giancardo of the Massachusetts Institute of Technology and his colleagues successfully discriminated between the groups solely by analyzing key hold times (the time required to press and release a key). Their analysis performed comparably or better than motor tests currently used in clinical settings.

As magnetism is the footprint of the interactive behaviour of electrons, studying it on the atomic level informs us about the collective electronic behaviour in the atomic environment. This can explain macroscopically observed electronic properties, like the temperature dependence of the conductivity. On the atomic level, magnetic ions are closely packed and thus mutually influence each other, resulting in the adoption of a common magnetic order to minimise their energy balance. A slight perturbation leads to a spin wave, whereby an oscillation of one magnetic moment around its central axis induces oscillating perturbations with a slight phase shift on the atomic neighbours. Spin waves are routinely observed in ordered magnetic materials by inelastic neutron scattering (INS) on spectrometers at the Institut Laue-Langevin (ILL). The magnetic moment is characterised by its spin number. The larger the spin number, the more appropriate it is to compare the atomic magnetic moment with a classical magnet. Lowering the spin means accentuating its quantum properties; exploring the transition into the quantum world, which is fundamentally different from the daily, macroscopic world, is one of the most exciting challenges in solid state physics. The most cited example is the spin -1/2 moments placed in the corner of an equidistant triangle. Due to its quantum nature, one spin can only point upwards or downwards with respect to its local axis. A magnetic exchange between the spin moments, that is antiferromagnetic in nature, forces them to align antiparallel to each other. As a quantum magnet cannot order, rather than adopting one ground state, several states are equally likely (6 in the case of the triangle), and the spins are in a super-positioned state pointing in several directions at once. Combining equidistant triangles leads to a two-dimensional network of spins. Its ground state, i.e. the spin arrangement with the lowest possible energy cost, has challenged theorists for decades. In 1973, noble laureate P.W. Anderson proposed a so-called 'quantum spin liquid state,' which is conceptually completely different to ordered magnetic phases. Anderson argued that for a triangular system, it is energetically more favourable for spins to organise into bonds. In these valence bonds, electrons are quantum mechanically 'entangled,' a purely quantum mechanical state. A superposition of a manifold of bond pattern exists in parallel and bonds fluctuate due to a quantum mechanical principle, which imposes zero point motions on the particles. This state is called a Resonant Valence Bond (RVB) state. Neutron scattering provides experimental proof for the RVB state Here at ILL, two cold three-axis spectrometers, IN14 and IN12, contributed over decades to the discovery and unravelling of magnetic correlations in classical and non-conventional superconductors, multiferroic crystals and a wide range of low-dimensional, frustrated and quantum magnetic systems. As both instruments dated from the 1980s, they were in need of a complete refurbishment to be able to continue contributing to the scientific progress in these fields. The new IN12 spectrometer's relocation and refurbishment was completed in 2012, and by the end of 2014, the IN14 spectrometer was replaced by its successor, ThALES. ThALES, Three-Axis instrument for Low Energy Spectroscopy, is a next generation cold neutron three-axis spectrometer that builds on the strengths of its predecessor, IN14, but uses state-of-the-art neutron optics. The ThALES project is a collaboration between ILL and Charles University, Prague, and is financed by the Czech Ministry of Science and Education. After replacing the IN14, ThALES became the new reference for cold single crystal neutron spectroscopy at a steady state neutron source like the ILL reactor. ThALES has been fully optimised to address the physics of highly correlated electron systems and scientific problems in the field of quantum magnetism. Moreover, the flexibility of the spectrometer has been enhanced through the implementation of various optical elements. The key aims of ThALES are: ThALES was used to carry out INS measurements in a recent study conducted by a collaboration of scientists, including ILL's Martin Boehm, current co-ordinator of the EU-funded neutron network SINE2020. The study published in Nature, titled 'Evidence for a spinon Fermi surface in a triangular lattice quantum-spin-liquid candidate,' argued that the triangular-lattice antiferromagnet YbMgGaO4 has the long sought quantum spin liquid RVB ground state. This study was the first to use neutron scattering as a means of providing experimental proof for the RVB state. The experimental effort to discover the RVB ground state has considerably increased since P.W. Anderson suggested that it might explain the phenomenon of superconductivity in a class of materials that show particularly high transition temperatures between a normal conducting and superconducting state. However, providing experimental proof for the existence of the RVB state is very challenging, because while a magnetically ordered system has a clear experimental response, the RVB state is characterised by the absence of a measurable quantity. Due to the lack of a measurable quantity, the experimental approach of this study, using ThALES, selected indirect experimental proof by deliberately exciting the ground state with neutrons and measuring the dynamic response. According to theoretical expectations, the excited spin liquid behaves 'exotically,' meaning the excited state is explained by spinons with very unusual properties. Spinons can rearrange the distribution of valence bonds and travel throughout the triangular plane with a minimum amount of energy. In a scattering process between the neutron and the spin liquid, the law of conservation of total momentum imposes the creation of two spin-1/2 spinons in the liquid. This pair of spinons travel in opposite directions with a total amount of energy equalling the loss of neutron energy in the scattering process. Using the ThALES spectrometer, it is possible to trace the direction and energies of the spinons by measuring the direction and energy of the neutron that created the spinon pair. In this way, this study traced a complete dynamical landscape of the spin quantum liquid in the triangular plane, and compared the measurements with theoretical predictions, which gave strong evidence for the existence of the spin liquid phase in YbMgGaO4. This research is important as a quantum spin liquid state of matter is potentially relevant for applications of quantum information. Moreover, experimental identification of a quantum spin liquid state contributes greatly to our understanding of quantum matter. Explore further: Novel state of matter: Observation of a quantum spin liquid More information: Yao Shen et al. Evidence for a spinon Fermi surface in a triangular-lattice quantum-spin-liquid candidate, Nature (2016). DOI: 10.1038/nature20614

Roithova J.,Charles University
Chemical Society Reviews | Year: 2012

In the last decade, we have experienced massive progress in spectroscopic methods for mass-selected ions. The aim of this tutorial review is to present action spectroscopy as a powerful tool for the investigation of ionic reaction intermediates. Examples span from ultraviolet and infrared photodissociation spectroscopy of model reaction intermediates to applications of infrared multiphoton dissociation spectroscopy (IRMPD) to intermediates directly sampled from reaction mixtures. The first example of double resonance IR-UV spectroscopy of model intermediates in an organometallic reaction is also mentioned. © 2012 The Royal Society of Chemistry.

Stepnika P.,Charles University
Chemical Society Reviews | Year: 2012

Compounds combining phosphine and carboxamide moieties in their molecules have developed virtually unnoticed into a specific class of highly structurally versatile and tuneable donor molecules finding manifold use in various fields, particularly in coordination chemistry, biomedical sciences and in catalysis. In the latter field, some phosphinoamides became the real privileged ligands and an indispensable part of a standard toolbox for synthetic chemists. This critical review aims to give an overview of the multifaceted chemistry of such compounds, paying attention to both the fundamentals and recent developments in this continuously expanding field. © 2012 The Royal Society of Chemistry.

Vitek L.,Charles University
Inflammatory Bowel Diseases | Year: 2015

Bile acid malabsorption (BAM) is a common but an underestimated and often neglected sign of inflammatory bowel diseases (IBDs), especially those affecting the distal ileum. Clinically relevant BAM is most often present in patients with Crohn's ileitis and particularly in ileal-resected Crohn's disease patients. However, deterioration of bile acid (BA) metabolism occurs also in patients with IBD without ileal disease or in those in clinical remission, and the role of BAM in these patients is not well appreciated by clinicians. In a majority of cases, BAM in IBD is caused by impaired conjugated BA reabsorption, mediated by apical sodium/BA cotransporting polypeptide, localized at the luminal surface of the ileal enterocytes. As a consequence, numerous pathological sequelae may occur, including the malfunction of lipid digestion with clinical steatorrhea, impaired intestinal motility, and/or significant changes in the intestinal microflora environment. In this review, a detailed description of the pathophysiological mechanisms of BAM-related diarrhea is presented. Although BAM is present in a significant number of patients with Crohn's disease, its laboratory assessment is not routinely included in diagnostic workups, partially because of costs, logistical reasons, or the unavailability of the more sophisticated laboratory equipment needed. Simultaneously, novel findings related to the effects of the BA signaling pathways on immune functions (mediated through TGR5, cell membrane G protein-coupled BA receptor 1, nuclear farnesoid X receptor, nuclear pregnane X receptor, or nuclear vitamin D receptor) are discussed along with intestinal metabolism in its relationship to the pathogenesis of IBD. Copyright © 2014 Crohn's & Colitis Foundation of America, Inc.

Flegr J.,Charles University
Trends in Parasitology | Year: 2013

For a long time, a latent toxoplasmosis, the lifelong presence of dormant stages of Toxoplasma in various tissues, including the brain, was considered harmless for immunocompetent persons. Within the past 10 years, however, many independent studies have shown that this parasitic disease, with a worldwide prevalence of about 30%, could be indirectly responsible for hundreds of thousands of deaths due to its effects on the rate of traffic and workplace accidents, and also suicides. Moreover, latent toxoplasmosis is probably one of the most important risk factors for schizophrenia. At least some of these effects, possibly mediated by increased dopamine and decreased tryptophan, are products of manipulation activity by Toxoplasma aiming to increase the probability of transmission from intermediate to definitive host through predation. © 2013.

The parasitic protozoan Toxoplasma gondii infects about one-third of the population of developed countries. The life-long presence of dormant stages of this parasite in the brain and muscular tissues of infected humans is usually considered asymptomatic from the clinical point of view. In the past 20?years, research performed mostly on military personnel, university students, pregnant women and blood donors has shown that this ?asymptomatic' disease has a large influence on various aspects of human life. Toxoplasma-infected subjects differ from uninfected controls in the personality profile estimated with two versions of Cattell's 16PF, Cloninger's TCI and Big Five questionnaires. Most of these differences increase with the length of time since the onset of infection, suggesting that Toxoplasma influences human personality rather than human personality influencing the probability of infection. Toxoplasmosis increases the reaction time of infected subjects, which can explain the increased probability of traffic accidents in infected subjects reported in three retrospective and one very large prospective case-control study. Latent toxoplasmosis is associated with immunosuppression, which might explain the increased probability of giving birth to a boy in Toxoplasma-infected women and also the extremely high prevalence of toxoplasmosis in mothers of children with Down syndrome. Toxoplasma-infected male students are about 3?cm taller than Toxoplasma-free subjects and their faces are rated by women as more masculine and dominant. These differences may be caused by an increased concentration of testosterone. Toxoplasma also appears to be involved in the initiation of more severe forms of schizophrenia. At least 40 studies confirmed an increased prevalence of toxoplasmosis among schizophrenic patients. Toxoplasma-infected schizophrenic patients differ from Toxoplasma-free schizophrenic patients by brain anatomy and by a higher intensity of the positive symptoms of the disease. Finally, five independent studies performed in blood donors, pregnant women and military personnel showed that RhD blood group positivity, especially in RhD heterozygotes, protects infected subjects against various effects of latent toxoplasmosis, such as the prolongation of reaction times, an increased risk of traffic accidents and excessive pregnancy weight gain. The modern human is not a natural host of Toxoplasma. Therefore, it can only be speculated which of the observed effects of latent toxoplasmosis are the result of the manipulation activity of the Toxoplasma aimed to increase the probability of its transmission from a natural intermediate to the definitive host by predation, and which are just side effects of chronic infection. © 2013 Published by The Company of Biologists Ltd.

The invention concerns an artificial vocal fold (1) consisting of two parts, in the transversal direction the two parts are slidingly placed in opposite walls of guide frame (5) and in the longitudinal direction they are attached to attachment wall (9) of guide frame (5) on one side and to attachment wall (9) of setting frame (6) on the opposite side, whereas inner area (4) of artificial vocal fold (1) is connected to a pressure fluid source. A method of tuning the vocal cord substitution as described in the invention lies in that the basic frequency of the human vocal fold is determined, on the basis of which an initial prestressing of the artificial vocal fold is created by setting-up a distance of guide frames (5) and setting frames (6) enclosing the artificial vocal folds, followed by changing vibration characteristics of the artificial vocal fold through changing the fluid pressure in the artificial vocal fold, the vibration characteristics are monitored and compared to the demanded vibration characteristics of the human vocal fold, until similarity of the compared vibration characteristics of the artificial and human vocal fold is achieved.

Charles University | Date: 2016-03-09

The device concerns the field of medical technology and consists of glasses (1) equipped with a sealed chamber (2) with valves (3) and a pressure sensor (4) connected to the input of the filtered power (9), which is connected to the signal filter (6) connected to the analogue/digital converter (7) and further to the computer (8). The filtered input power (9) can also be connected to the ECG (10) connected to the signal filter (6) connected to the analogue/digital converter (7) and further to the computer (8). The filtered input power (9) can be also connected to the sensor (12) of the perfusion connected to the power filter (5) connected to the analogue/digital convertor (7) and further to the computer (8).Valves (3) is usually connected to the actuating moduls (14) connected to the computer (8).

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