We present an active alignment and stabilization control system for laser setups based on a thin-disk regenerative amplifier. This method eliminates power and pointing instability during the warm-up period and improves long-term stability throughout the entire operation. The alignment method is based on a four-mirror control system consisting of two motorized mirrors placed within the regenerative amplifier cavity, two additional motorized mirrors external to the amplifier cavity, and four camera detectors. The implemented stabilization system achieves significant performance improvements, increasing the power stability from 1.87% to 0.79% RMS and the peak-to-peak stability from 7.43% to 3.88%. Furthermore, the system significantly enhances beam positional stability, achieving up to a sixfold improvement in certain sensor measurements. The advantage of this method is the removal of long-term pointing instability by adding a second controlled motorized mirror to the cavity, in addition to using only one cavity end mirror for optimizing the overlap with the pump spot on the cavity medium. To achieve higher precision in pointing, the nonlinear hysteresis effect of the piezoelectric actuator is mitigated. Although the power and pointing stability of the cavity are secured, pointing instability at the input of the compressor occurs. This issue is resolved by two additional controlled motorized mirrors external to the cavity.
- Publikační typ
- časopisecké články MeSH
Cancer treatment brings about a phenomenon not fully clarified yet, termed chemobrain. Its strong negative impact on patients' well-being makes it a trending topic in current research, interconnecting many disciplines from clinical oncology to neuroscience. Clinical and animal studies have often reported elevated concentrations of proinflammatory cytokines in various types of blood cancers. This inflammatory burst could be the background for chemotherapy-induced cognitive deficit in patients with blood cancers. Cancer environment is a dynamic interacting system. The review puts into close relationship the inflammatory dysbalance and oxidative/nitrosative stress with disruption of the blood-brain barrier (BBB). The BBB breakdown leads to neuroinflammation, followed by neurotoxicity and neurodegeneration. High levels of intracellular reactive oxygen species (ROS) induce the progression of cancer resulting in increased mutagenesis, conversion of protooncogenes to oncogenes, and inactivation of tumor suppression genes to trigger cancer cell growth. These cell alterations may change brain functionality, as well as morphology. Multidrug chemotherapy is not without consequences to healthy tissue and could even be toxic. Specific treatment impacts brain function and morphology, functions of the immune system, and metabolism in a unique mixture. In general, a chemo-drug's effects on cognition in cancer are not direct and/or in-direct, usually a combination of effects is more probable. Last but not least, chemotherapy strongly impacts the immune system and could contribute to BBB disruption. This review points out inflammation as a possible mechanism of brain damage during blood cancers and discusses chemotherapy-induced cognitive impairment.
- Klíčová slova
- BBB, blood cancer, chemobrain, chemotherapy, neuroinflammation,
- MeSH
- hematologické nádory * metabolismus patologie MeSH
- imunitní systém MeSH
- kognitivní porucha po chemoterapii * metabolismus patologie MeSH
- lidé MeSH
- mozek metabolismus MeSH
- nádory * farmakoterapie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
OBJECTIVES: NREM parasomnias also known as disorders of arousal (DOA) are characterised by abnormal motor and autonomic activation during arousals primarily from slow wave sleep. Dissociative state between sleep and wake is likely responsible for clinical symptoms of DOA. We therefore investigated potential dissociation outside of parasomnic events by using simultaneous 256-channel EEG (hdEEG) and functional magnetic resonance imaging (fMRI). METHODS: Eight DOA patients (3 women, mean age = 27.8; SD = 4.2) and 8 gender and age matched healthy volunteers (3 women, mean age = 26,5; SD = 4.0) were included into the study. They underwent 30-32 h of sleep deprivation followed by hdEEG and fMRI recording. We determined 2 conditions: falling asleep (FA) and arousal (A), that occurred outside of deep sleep and/or parasomnic event. We used multimodal approach using data obtained from EEG, fMRI and EEG-fMRI integration approach. RESULTS: DOA patients showed increase in delta and beta activity over postcentral gyrus and cuneus during awakening period. This group expressed increased connectivity between motor cortex and cingulate during arousals unrelated to parasomnic events in the beta frequency band. They also showed lower connectivity between different portions of cingulum. In contrast, the greater connectivity was found between thalamus and some cortical areas, such as occipital cortex. CONCLUSION: Our findings suggest a complex alteration in falling asleep and arousal mechanisms at both subcortical and cortical levels in response to sleep deprivation. As this alteration is present also outside of slow wave sleep and/or parasomnic episodes we believe this could be a trait factor of DOA.
- Klíčová slova
- Disorders of arousal, Functional brain imaging, HdEEG and fMRI integration, High density EEG, Parasomnias, Slow wave sleep,
- Publikační typ
- časopisecké články MeSH
One of the remaining challenges in magnetic thermonuclear fusion is survival of the heat shield protecting the tokamak reactor vessel against excessive plasma heat fluxes. Unmitigated high confinement edge localized mode (ELM) is a regular heat pulse damaging the heat shield. We suggest a novel concept of magnetic sweeping of the plasma contact strike point fast and far enough in order to spread this heat pulse. We demonstrate feasibility of a dedicated copper coil in a resonant circuit, including the induced currents and power electronics. We predict the DEMO ELM properties, simulate heat conduction, 3D particles motion and magnetic fields of the plasma and coil in COMSOL Multiphysics and Matlab. The dominant system parameter is voltage, feasible 18 kV yields 1 kHz sweeping frequency, suppressing the ELM-induced surface temperature rise by a factor of 3. Multiplied by other known mitigation concepts, ELMs might be mitigated enough to ensure safe operation of DEMO.
- Publikační typ
- časopisecké články MeSH
Purpose Phonations into a tube with the distal end either in the air or submerged in water are used for voice therapy. This study explores the effective mechanisms of these therapy methods. Method The study applied a physical model complemented by calculations from a computational model, and the results were compared to those that have been reported for humans. The effects of tube phonation on vocal tract resonances and oral pressure variation were studied. The relationships of transglottic pressure variation in time Ptrans ( t) versus glottal area variation in time GA( t) were constructed. Results The physical model revealed that, for the phonation on [u:] vowel through a glass resonance tube ending in the air, the 1st formant frequency ( F1 ) decreased by 67%, from 315 Hz to 105 Hz, thus slightly above the fundamental frequency ( F0 ) that was set to 90-94 Hz . For phonation through the tube into water, F1 decreased by 91%-92%, reaching 26-28 Hz, and the water bubbling frequency Fb ≅ 19-24 Hz was just below F1 . The relationships of Ptrans ( t) versus GA( t) clearly differentiate vowel phonation from both therapy methods, and show a physical background for voice therapy with tubes. It is shown that comparable results have been measured in humans during tube therapy. For the tube in air, F1 descends closer to F0 , whereas for the tube in water, the frequency Fb occurs close to the acoustic-mechanical resonance of the human vocal tract. Conclusion In both therapy methods, part of the airflow energy required for phonation is substituted by the acoustic energy utilizing the 1st acoustic resonance. Thus, less flow energy is needed for vocal fold vibration, which results in improved vocal efficiency. The effect can be stronger in water resistance therapy if the frequency Fb approaches the acoustic-mechanical resonance of the vocal tract, while simultaneously F0 is voluntarily changed close to F1.
- MeSH
- akustika řeči MeSH
- fonace fyziologie MeSH
- glottis MeSH
- hlasový trénink MeSH
- lidé MeSH
- modely anatomické MeSH
- plíce fyziologie MeSH
- počítačová simulace MeSH
- řečová terapie metody MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The regional distribution of white matter (WM) abnormalities in schizophrenia remains poorly understood, and reported disease effects on the brain vary widely between studies. In an effort to identify commonalities across studies, we perform what we believe is the first ever large-scale coordinated study of WM microstructural differences in schizophrenia. Our analysis consisted of 2359 healthy controls and 1963 schizophrenia patients from 29 independent international studies; we harmonized the processing and statistical analyses of diffusion tensor imaging (DTI) data across sites and meta-analyzed effects across studies. Significant reductions in fractional anisotropy (FA) in schizophrenia patients were widespread, and detected in 20 of 25 regions of interest within a WM skeleton representing all major WM fasciculi. Effect sizes varied by region, peaking at (d=0.42) for the entire WM skeleton, driven more by peripheral areas as opposed to the core WM where regions of interest were defined. The anterior corona radiata (d=0.40) and corpus callosum (d=0.39), specifically its body (d=0.39) and genu (d=0.37), showed greatest effects. Significant decreases, to lesser degrees, were observed in almost all regions analyzed. Larger effect sizes were observed for FA than diffusivity measures; significantly higher mean and radial diffusivity was observed for schizophrenia patients compared with controls. No significant effects of age at onset of schizophrenia or medication dosage were detected. As the largest coordinated analysis of WM differences in a psychiatric disorder to date, the present study provides a robust profile of widespread WM abnormalities in schizophrenia patients worldwide. Interactive three-dimensional visualization of the results is available at www.enigma-viewer.org.
- MeSH
- bílá hmota patofyziologie ultrastruktura MeSH
- corpus callosum patofyziologie MeSH
- difuzní magnetická rezonance metody MeSH
- dospělí MeSH
- kohortové studie MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladý dospělý MeSH
- mozek patofyziologie MeSH
- počítačové zpracování obrazu MeSH
- schizofrenie diagnostické zobrazování patofyziologie MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- zobrazování difuzních tenzorů metody MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
BACKGROUND: Cognitive impairment (impairment of memory, attention, or concentration) is documented in 17-75% of patients with various malignancies treated with chemotherapeutic agents that worsen quality of life. CRCI affects patients of all ages. The impairment of cognitive function in connection with chemotherapy is usually mild, but an event. relationship with dementia remains to be confirmed. Chemotherapy in combination with radiotherapy in Hodgkin lymphoma can cure 80-90% of patients. AIM: This review summarizes the most frequently observed changes in cognitive function in patients suffering from CRCI. The article further describes the possible pathophysiological mechanisms behind these changes and the risk factors that can increase the likelihood of cognitive functional impairment after chemotherapy of malignant tumors. Special attention is given to how this relates to Hodgkins lymphoma. We also discuss the neuroprotective factors involved in chemotherapy-related cognitive impairment and its treatment options. CONCLUSION: Changes occur mainly in the ability to learn and remember, in the speed of reactions, and in attention and executive functions. Although CRCI pathophysiological mechanisms are complex and not yet fully understood, the involvement of neurotoxicity, such as that induced by treatment, anemia, higher levels of oxidative stress and inflammatory responses, genetic factors, and reduced brain connectivity is discussed. CRCI is further modified by comorbidities and patient age. Pharmacological and nonpharmacological treatment options for CRCI are outlined.Key words: Hodgkin lymphoma - chemotherapy - cognitive impairment - risk factors The project was supported by the grant of the Agency for the Czech Republic Health Research of the Ministry of Health of the Czech Republic 16-29857A and by the project Sustainability for the National Institute of Mental Health No. LO1611 with a financial support of the Ministry of Education, Youth and Sports of the Czech Republic in the frame of the National Sustainability Programme I. The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers.Submitted: 29. 9. 2016Accepted: 12. 2. 2017.
- MeSH
- antitumorózní látky škodlivé účinky MeSH
- Hodgkinova nemoc farmakoterapie MeSH
- kognitivní dysfunkce chemicky indukované MeSH
- lidé MeSH
- rizikové faktory MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
- Názvy látek
- antitumorózní látky MeSH
RATIONALE: Self-report studies indicate that cannabis could increase sexual desire in some users. We hypothesized that intoxication increases activation of brain areas responsive to visual erotica, which could be useful in the treatment of hypoactive sexual desire disorder, a condition marked by a lack of sexual desire. OBJECTIVES: The aim of this study is to assess the aphrodisiacal properties of cannabis. METHODS: We conducted an open-randomized study with 21 heterosexual casual cannabis users. A 3T MRI was used to measure brain activation in response to erotic pictures. Blood samples were collected to determine the serum levels of cannabinoids, cortisol and prolactin. Participants were grouped according to whether they had ever experienced any aphrodisiacal effects during intoxication (Group A) or not (Group non-A). RESULTS: Intoxication was found to significantly increase activation in the right nucleus accumbens in the Group A while significantly decreasing activation in the Group non-A. There was also a significant interaction between the group and intoxication, with elevated prolactin in the Group non-A during intoxication. No intoxication-related differences in subjective picture evaluations were found. CONCLUSION: Cannabis intoxication increases activation of the right nucleus accumbens to erotic stimuli. This effect is limited to users whose prolactin is not elevated in response to intoxication. This effect may be useful in the treatment of low sexual desire.
- Klíčová slova
- Cannabis, Cortisol, Dopamine, Hypoactive sexual desire, Hypothalamus, Nucleus accumbens, Prolactin, fMRI,
- MeSH
- Cannabis metabolismus toxicita MeSH
- erotika MeSH
- fixní kombinace léků MeSH
- hydrokortison krev MeSH
- hypnotika a sedativa MeSH
- kanabidiol krev chemie MeSH
- libido etika fyziologie MeSH
- lidé MeSH
- magnetická rezonanční tomografie MeSH
- mozek fyziologie MeSH
- nucleus accumbens MeSH
- pilotní projekty MeSH
- prolaktin krev MeSH
- tetrahydrokanabinol krev chemie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- fixní kombinace léků MeSH
- hydrokortison MeSH
- hypnotika a sedativa MeSH
- kanabidiol MeSH
- nabiximols MeSH Prohlížeč
- prolaktin MeSH
- tetrahydrokanabinol MeSH
BACKGROUND: Latent toxoplasmosis, the life-long presence of dormant stages of Toxoplasma in immunoprivileged organs and of anamnestic IgG antibodies in blood, affects about 30% of humans. Infected subjects have an increased incidence of various disorders, including schizophrenia. Several studies, as well as the character of toxoplasmosis-associated disturbance of neurotransmitters, suggest that toxoplasmosis could also play an etiological role in Obsessive-Compulsive Disorder (OCD). METHODS: The aim of the present cross-sectional study performed on a population of 7471 volunteers was to confirm the association between toxoplasmosis and OCD, and toxoplasmosis and psychological symptoms of OCD estimated by the standard Obsessive-Compulsive Inventory-Revised (OCI-R). RESULTS: Incidence of OCD was 2.18% (n=39) in men and 2.28% (n=83) in women. Subjects with toxoplasmosis had about a 2.5 times higher odds of OCD and about a 2.7 times higher odds of learning disabilities. The incidence of 18 other neuropsychiatric disorders did not differ between Toxoplasma-infected and Toxoplasma-free subjects. The infected subjects, even the OCD-free subjects, scored higher on the OCI-R. LIMITATIONS: Examined subjects provided the information about their toxoplasmosis and OCD statuses themselves, which could result in underrating the strength of observed associations. CONCLUSIONS: The results confirmed earlier reports of the association between toxoplasmosis and OCD. They also support recent claims that latent toxoplasmosis is in fact a serious disease with many impacts on quality of life of patients.
- Klíčová slova
- Infection, Learning disabilities, Mental disorder, Parasites, Risk factors, Toxoplasmosis,
- MeSH
- dospělí MeSH
- kočky MeSH
- kvalita života MeSH
- lidé středního věku MeSH
- lidé MeSH
- neparametrická statistika MeSH
- obsedantně kompulzivní porucha diagnóza parazitologie psychologie MeSH
- průřezové studie MeSH
- schizofrenie diagnóza parazitologie MeSH
- Toxoplasma MeSH
- toxoplazmóza komplikace přenos MeSH
- zvířata MeSH
- Check Tag
- dospělí MeSH
- kočky MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The ball-pen probe (BPP) technique is used successfully to make profile measurements of the electron temperature on the ASDEX Upgrade (Axially Symmetric Divertor Experiment), COMPASS (COMPact ASSembly), and ISTTOK (Instituto Superior Tecnico TOKamak) tokamak. The electron temperature is provided by a combination of the BPP potential (ΦBPP) and the floating potential (Vfl) of the Langmuir probe (LP), which is compared with the Thomson scattering diagnostic on ASDEX Upgrade and COMPASS. Excellent agreement between the two diagnostics is obtained for circular and diverted plasmas and different heating mechanisms (Ohmic, NBI, ECRH) in deuterium discharges with the same formula Te = (ΦBPP - Vfl)/2.2. The comparative measurements of the electron temperature using BPP/LP and triple probe (TP) techniques on the ISTTOK tokamak show good agreement of averaged values only inside the separatrix. It was also found that the TP provides the electron temperature with significantly higher standard deviation than BPP/LP. However, the resulting values of both techniques are well in the phase with the maximum of cross-correlation function being 0.8.
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
