Ubiquinone (UQ), the only known electron carrier in the mammalian electron transport chain (ETC), preferentially delivers electrons to the terminal electron acceptor oxygen (O2). In hypoxia, ubiquinol (UQH2) diverts these electrons onto fumarate instead. Here, we identify rhodoquinone (RQ), an electron carrier detected in mitochondria purified from certain mouse and human tissues that preferentially delivers electrons to fumarate through the reversal of succinate dehydrogenase, independent of environmental O2 levels. The RQ/fumarate ETC is strictly present in vivo and is undetectable in cultured mammalian cells. Using genetic and pharmacologic tools that reprogram the ETC from the UQ/O2 to the RQ/fumarate pathway, we establish that these distinct ETCs support unique programs of mitochondrial function and that RQ confers protection upon hypoxia exposure in vitro and in vivo. Thus, in discovering the presence of RQ in mammals, we unveil a tractable therapeutic strategy that exploits flexibility in the ETC to ameliorate hypoxia-related conditions.

• MeSH
• elektrony MeSH
• fumaráty metabolismus   MeSH
• hypoxie metabolismus   MeSH
• kyslík metabolismus   MeSH
• lidé MeSH
• mitochondrie * metabolismus   MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• sukcinátdehydrogenasa metabolismus   MeSH
• transport elektronů MeSH
• ubichinon * metabolismus   analogy a deriváty   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Ultra-short electron beams are used as ultra-fast radiation source for radiobiology experiments aiming at very high energy electron beams (VHEE) radiotherapy with very high dose rates. Laser plasma accelerators are capable of producing electron beams as short as 1 fs and with tunable energy from few MeV up to multi-GeV with compact footprint. This makes them an attractive source for applications in different fields, where the ultra-short (fs) duration plays an important role. The time dynamics of the dose deposited by electron beams with energies in the range 50-250 MeV have been studied and the results are presented here. The results set a quantitative limit to the maximum dose rate at which the electron beams can impart dose.

• MeSH
• částice - urychlovače * MeSH
• celková dávka radioterapie MeSH
• elektrony * MeSH
• lasery MeSH
• metoda Monte Carlo MeSH
• radiometrie metody   MeSH
• vysokoenergetická radioterapie MeSH
• Publikační typ
• časopisecké články MeSH

Objective.This work presents a method for enhanced detection, imaging, and measurement of the thermal neutron flux.Approach. Measurements were performed in a water tank, while the detector is positioned out-of-field of a 20 MeV ultra-high pulse dose rate electron beam. A semiconductor pixel detector Timepix3 with a silicon sensor partially covered by a6LiF neutron converter was used to measure the flux, spatial, and time characteristics of the neutron field. To provide absolute measurements of thermal neutron flux, the detection efficiency calibration of the detectors was performed in a reference thermal neutron field. Neutron signals are recognized and discriminated against other particles such as gamma rays and x-rays. This is achieved by the resolving power of the pixel detector using machine learning algorithms and high-resolution pattern recognition analysis of the high-energy tracks created by thermal neutron interactions in the converter.Main results. The resulting thermal neutrons equivalent dose was obtained using conversion factor (2.13(10) pSv·cm2) from thermal neutron fluence to thermal neutron equivalent dose obtained by Monte Carlo simulations. The calibrated detectors were used to characterize scattered radiation created by electron beams. The results at 12.0 cm depth in the beam axis inside of the water for a delivered dose per pulse of 1.85 Gy (pulse length of 2.4μs) at the reference depth, showed a contribution of flux of 4.07(8) × 103particles·cm-2·s-1and equivalent dose of 1.73(3) nSv per pulse, which is lower by ∼9 orders of magnitude than the delivered dose.Significance. The presented methodology for in-water measurements and identification of characteristic thermal neutrons tracks serves for the selective quantification of equivalent dose made by thermal neutrons in out-of-field particle therapy.

• MeSH
• algoritmy * MeSH
• elektrony * MeSH
• kalibrace MeSH
• neutrony MeSH
• záření gama MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Carbon and its analogous nanomaterials are beneficial for toxic gas sensors since they are used to increase the electrochemically active surface region and improve the transmission of electrons. The present article addresses a detailed investigation on the potential of the monolayer PC3 compound as a possible sensor material for environmentally toxic nitrogen-containing gases (NCGs), namely NH3, NO, and NO2. The entire work is carried out under the frameworks of density functional theory, ab-initio molecular dynamics simulations, and non-equilibrium Green's function approaches. The monolayer-gas interactions are studied with the van der Waals dispersion correction. The stability of pristine monolayer PC3 is confirmed through dynamical, mechanical, and thermal analyses. The mobility and relaxation time of 2D PC3 sensor material with NCGs are obtained in the range of 101-104 cm2 V-1 s-1 and 101-103 fs for armchair and zigzag directions, respectively. Out of six possible adsorption sites for toxic gases on the PC3 surface, the most prominent site is identified with the highest adsorption energy for all the NCGs. Considering the most stable configuration site of the NCGs, we have obtained relevant electronic properties by utilizing the band unfolding technique. The considerable adsorption energies are obtained for NO and NO2 compared to NH3. Although physisorption is observed for all the NCGs on the PC3 surface, NO2 is found to convert into NO and O at 5.05 ps (at 300 K) under molecular dynamics simulation. The maximum charge transfer (0.31e) and work function (5.17 eV) are observed for the NO2 gas molecule in the series. Along with the considerable adsorption energies for NO and NO2 gas molecules, their shorter recovery time (0.071 s and 0.037 s, respectively) from the PC3 surface also identifies 2D PC3 as a promising sensor material for those environmentally toxic gases. The experimental viability and actual implications for PC3 monolayer as NCGs sensor material are also confirmed by examining the humidity effect and transport properties with modeled sensor devices. The transport properties (I-V characteristics) reflect the significant sensitivity of PC3 monolayer toward NO and NO2 molecules. These results certainly confirm PC3 monolayer as a promising sensor material for NO and NO2 NCG molecules.

• MeSH
• adsorpce MeSH
• dusík MeSH
• elektrony MeSH
• nanostruktury * MeSH
• plyny * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

This article summarizes the importance of the exact morphology of human uterine/fallopian tube epithelium at the scanning electron microscopy (SEM) level for the clinical outcome even nowadays. Visual referential micrographs from SEM reflect two ways to view human epithelial cell lining surfaces: the surface epithelial uterine tube from surgical tissue biopsy and human fallopian tube epithelial cells (HFTEC) culture monolayer surface. One colorized image visualizes ciliated cells, distinguishes them from non-ciliated cells, and provides an educational benefit. A detailed description of the ultrastructure in referential and pathologic human uterine tube epithelium is important in defining the morphological basis of high-grade carcinomas, in the mechanism of pathophysiology, and in discussing options for its prevention. Cell cultures of human fallopian tube epithelial cells offer new approaches in simulating the mechanisms of cancer genesis or may help to elucidate the genetic basis of several diagnoses. New technical approaches in SEM provide higher resolution and detailed surface images. The SEM modality is still one of the current options in diagnostics and may be useful for advancing human reproductive organ cancer research.

• MeSH
• biopsie MeSH
• buněčné kultury MeSH
• elektrony * MeSH
• epitel MeSH
• epitelové buňky MeSH
• lidé MeSH
• mikroskopie elektronová rastrovací MeSH
• vejcovody * patologie   fyziologie   MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Uterine tubes (UTs) are essential during physiological reproduction. The most intriguing part of its wall is the mucosa. Apart from the epithelial cells vital for its normal function, the connective tissue lamina propria contains wide spaces whose function, morphology and structure are yet to be elucidated. The present study used bioptic samples from 25 premenopausal (mean age 48,33 years, ?=3,56) and 25 postmenopausal women (mean age 57,8 years, ?=7,79). In both study groups, samples were obtained from two anatomically distinct parts of the UT - ampulla and infundibulum with fimbriae. The specimens were processed for scanning electron microscopy (SEM) and immunohistochemical detection of podoplanin (clone D2-40) and VEGFR-3 - two markers of lymphatic endothelial cells. The results showed that specimens from premenopausal and postmenopausal women contain wide lymphatic spaces, also known as lymphatic lacunae. The most probable function of the lacunae in the fimbriae is oocyte pick-up upon ovulation thanks to their ability to get engorged with lymph, thus serving as an erectile-like tissue. The ampullary lacunae are probably responsible for tubal fluid maintenance and recirculation. These results indicate that they are vital for normal reproduction because tubal fluid dynamics are as important as fluid composition. Further research on this topic is highly warranted because more detailed insights into UT function have a great potential to refine the methods of reproductive medicine, e.g. in vitro fertilization (IVF), which are still far from optimal regarding fertility outcomes.

• MeSH
• elektrony MeSH
• endoteliální buňky * MeSH
• lidé MeSH
• mikroskopie elektronová rastrovací MeSH
• sliznice MeSH
• vejcovody * fyziologie   ultrastruktura   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

We present a computational case study of X-ray single-particle imaging of hydrated proteins on an example of 2-Nitrogenase-Iron protein covered with water layers of various thickness, using a start-to-end simulation platform and experimental parameters of the SPB/SFX instrument at the European X-ray Free-Electron Laser facility. The simulations identify an optimal thickness of the water layer at which the effective resolution for imaging the hydrated sample becomes significantly higher than for the non-hydrated sample. This effect is lost when the water layer becomes too thick. Even though the detailed results presented pertain to the specific sample studied, the trends which we identify should also hold in a general case. We expect these findings will guide future single-particle imaging experiments using hydrated proteins.

• MeSH
• difrakce rentgenového záření přístrojové vybavení   metody   MeSH
• elektrony MeSH
• fotony MeSH
• lasery * MeSH
• molekulární zobrazování metody   MeSH
• oxidoreduktasy chemie   účinky záření   MeSH
• rentgenové záření škodlivé účinky   MeSH
• simulace molekulární dynamiky * MeSH
• voda chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

UHDpulse - Metrology for advanced radiotherapy using particle beams with ultra-high pulse dose rates is a recently started European Joint Research Project with the aim to develop and improve dosimetry standards for FLASH radiotherapy, very high energy electron (VHEE) radiotherapy and laser-driven medical accelerators. This paper gives a short overview about the current state of developments of radiotherapy with FLASH electrons and protons, very high energy electrons as well as laser-driven particles and the related challenges in dosimetry due to the ultra-high dose rate during the short radiation pulses. We summarize the objectives and plans of the UHDpulse project and present the 16 participating partners.

• MeSH
• částice - urychlovače MeSH
• celková dávka radioterapie MeSH
• elektrony * MeSH
• lasery MeSH
• protony MeSH
• radiometrie * MeSH
• radioterapie MeSH
• vysokoenergetická radioterapie MeSH
• Publikační typ
• časopisecké články MeSH

We report experimental results of low-energy electron interactions with.

• MeSH
• chemické modely MeSH
• dlaždicobuněčné karcinomy hlavy a krku chemie   farmakoterapie   radioterapie   MeSH
• dusíkaté sloučeniny chemie   farmakologie   MeSH
• elektrony * MeSH
• ionizující záření MeSH
• lidé MeSH
• molekulární modely MeSH
• nádorové buněčné linie MeSH
• nádory hypofaryngu chemie   farmakoterapie   radioterapie   MeSH
• pyrimidiny chemie   farmakologie   MeSH
• radiosenzibilizující látky chemie   farmakologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Mitochondrial metabolic remodeling is a hallmark of the Trypanosoma brucei digenetic life cycle because the insect stage utilizes a cost-effective oxidative phosphorylation (OxPhos) to generate ATP, while bloodstream cells switch to aerobic glycolysis. Due to difficulties in acquiring enough parasites from the tsetse fly vector, the dynamics of the parasite's metabolic rewiring in the vector have remained obscure. Here, we took advantage of in vitro-induced differentiation to follow changes at the RNA, protein, and metabolite levels. This multi-omics and cell-based profiling showed an immediate redirection of electron flow from the cytochrome-mediated pathway to an alternative oxidase (AOX), an increase in proline consumption, elevated activity of complex II, and certain tricarboxylic acid (TCA) cycle enzymes, which led to mitochondrial membrane hyperpolarization and increased reactive oxygen species (ROS) levels. Interestingly, these ROS molecules appear to act as signaling molecules driving developmental progression because ectopic expression of catalase, a ROS scavenger, halted the in vitro-induced differentiation. Our results provide insights into the mechanisms of the parasite's mitochondrial rewiring and reinforce the emerging concept that mitochondria act as signaling organelles through release of ROS to drive cellular differentiation.

• MeSH
• adenosintrifosfát biosyntéza   MeSH
• buněčná diferenciace účinky léků   MeSH
• buněčné dýchání účinky léků   MeSH
• buněčné linie MeSH
• elektrony MeSH
• glukosa farmakologie   MeSH
• membránový potenciál mitochondrií účinky léků   MeSH
• metabolické sítě a dráhy účinky léků   MeSH
• metabolomika * MeSH
• mitochondriální proteiny metabolismus   MeSH
• mitochondrie účinky léků   metabolismus   MeSH
• oxidace-redukce MeSH
• oxidoreduktasy metabolismus   MeSH
• prolin metabolismus   MeSH
• proteom metabolismus   MeSH
• protozoální proteiny metabolismus   MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• rostlinné proteiny metabolismus   MeSH
• signální transdukce MeSH
• transkriptom genetika   MeSH
• transport elektronů účinky léků   MeSH
• Trypanosoma brucei brucei účinky léků   genetika   růst a vývoj   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH