Phosphorus (P) precipitation is among the most effective treatments to mitigate lake eutrophication. However, after a period of high effectiveness, studies have shown possible re-eutrophication and the return of harmful algal blooms. While such abrupt ecological changes were attributed to the internal P loading, the role of lake warming and its potential synergistic effects with internal loading, thus far, has been understudied. Here, in a eutrophic lake in central Germany, we quantified the driving mechanisms of the abrupt re-eutrophication and cyanobacterial blooms in 2016 (30 years after the first P precipitation). A process-based lake ecosystem model (GOTM-WET) was established using a high-frequency monitoring data set covering contrasting trophic states. Model analyses suggested that the internal P release accounted for 68% of the cyanobacterial biomass proliferation, while lake warming contributed to 32%, including direct effects via promoting growth (18%) and synergistic effects via intensifying internal P loading (14%). The model further showed that the synergy was attributed to prolonged lake hypolimnion warming and oxygen depletion. Our study unravels the substantial role of lake warming in promoting cyanobacterial blooms in re-eutrophicated lakes. The warming effects on cyanobacteria via promoting internal loading need more attention in lake management, particularly for urban lakes.

• Klíčová slova
• GOTM-WET, climate change, cyanobacterial blooms, eutrophication, internal loading, phosphorus precipitation,
• MeSH
• ekosystém MeSH
• eutrofizace MeSH
• fosfor analýza   MeSH
• jezera * mikrobiologie   MeSH
• sinice * MeSH
• škodlivý vodní květ MeSH
• živiny MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Čína MeSH
• Názvy látek
• fosfor MeSH

Contemporary health care is facing deep personal crisis appearing mainly in nurses. It particularly involves departments characterized by mentally and physically demanding workload especially departments of internal medicine, that are immediately endangered by the lack of the nursing staff. The importance and capability of motivation come to fore among other factors. Enough motivation could decrease the decline of nursing staff and lead to the increase of interest in work at departments of internal medicine. The article summarizes basic principles of motivation that is possible to employ.

• Klíčová slova
• department of internal medicine, incentive, nurse, treatment indications,
• MeSH
• lidé MeSH
• motivace * MeSH
• postoj zdravotnického personálu * MeSH
• pracovní zátěž MeSH
• průzkumy a dotazníky MeSH
• vnitřní lékařství MeSH
• zdravotní sestry MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

As a light structure, composite sandwich panels are distinguished by their significant bending stiffness that is rapidly used in the manufacture of aircraft bodies. This study focuses on the mechanical behaviour of through-thickness polymer, pin-reinforced foam core sandwich panels subjected to indentation and low impact loading. Experimental and computational approaches are used to study the global and internal behaviour of the sandwich panel. The samples for experimental testing were made from glass/polyester laminates as the face sheets and polyurethane foam as the foam core. To further reinforce the samples against bending, different sizes of polymeric pins were implemented on the sandwich panels. The sandwich panel was fabricated using the vacuum infusion process. Using the experimental data, a finite element model of the sample was generated in LS-DYNA software, and the effect of pin size and loading rate were examined. Results of the simulation were validated through a proper prediction compared to the test data. The results of the study show that using polymeric pins, the flexural strength of the panel significantly increased under impact loading. In addition, the impact resistance of the pin-reinforced foam core panel increased up to 20%. Moreover, the size of pins has a significant influence on the flexural behaviour while the sample was under a moderate strain rate. To design an optimum pin-reinforced sandwich panel a "design of experiment model" was generated to predict energy absorption and the maximum peak load of proposed sandwich panels. The best design of the panel is recommended with 1.8 mm face sheet thickness and 5 mm pins diameter.

• Klíčová slova
• composite panel, energy absorption, finite element model, low impact loading, pin-reinforced sandwich panel,
• Publikační typ
• časopisecké články MeSH

Due to the internal structure of the knee joint, the ability to characterize and quantify the dynamic response of the meniscal tissue directly in vivo is highly problematic. The main purpose of this study was to investigate the behaviour of the meniscus under loading conditions. Four healthy young females were included. To obtain T2* values in the meniscus, the vTE sequence was used with 10 echoes ranging from 0.8 to 10.1 ms. Submilisecond first echo time is a great advantage of vTE sequence allowing for precise mapping of relatively short T2*. The two-parametric least squares fitting procedure was used to calculate T2* pixel-wise. A custom-made diamagnetic apparatus was developed to simulate stress conditions on the lower limb in a conventional MR scanner. vTE T2* was performed in five consecutive scans, 6:10 min apart. Three different compartments of the medial and lateral meniscus were segmented. The differences at the different time-points were calculated. A constant increase of T2* times after compression was statistically significant in the anterior horn of the medial meniscus. T2* mapping with variable echo time sequence might be a satisfactorily sensitive technique to detect the changes of meniscus physiology under loading conditions in vivo.

• Klíčová slova
• Loading, MRI, Meniscus, T2* changes, vTE,
• Publikační typ
• časopisecké články MeSH

PURPOSE OF THE STUDY Vertically unstable transforaminal sacral fractures can be stabilized with several types of transiliac internal fixators (TIFI): the classical one (TIFI-C), the supraacetabular one (TIFI-A) and by dual application of TIFI (DTIFI). MATERIAL AND METHODS Pelvic models made of solid foam (Sawbones 1301) were used in the study. Mechanical loading tests were performed in order to assess the stiffness of the studied pelvic structures. The stiffness of the intact model was approximated as the slope of load/displacement curve. Then vertically unstable right-sided linear transforaminal fracture was created and subsequently fixed by TIFI-C, TIFI-A and DTIFI (each fixator for a separate model). The fixation techniques were compared based on the ratio between the stiffness of the treated and of the intact pelvis. Motion of the posterior pelvic structures and their deformations were measured using a photogrammetric system with four synchronous cameras. Loads applied at the base of sacrum and sacral base displacements were recorded by the testing device and used to assess the stiffness of the model structure. A dedicated load cell and a monoaxial extensometer were utilised. Every measurement was repeated at least 10 times. Obtained data were analysed by one way ANOVA test with post hoc comparison by Tukey HSD test. RESULTS Mean stiffness ratio (±1SD) of pelvic structure was 0.638 ± 0.005 for TIFI-C, 0.722 ± 0.014 for TIFI-A and 0.720 ± 0.008 for DTIFI. Dual transiliac internal fixation and supraacetabular fixation were superior to the classical one (p < 0.0001), but DTIFI and TIFI-A stiffness ratios were statistically equivalent (p = 0.9112). CONCLUSIONS Results of the mechanical analysis using pelvic models indicate that for linear vertical transforaminal sacral fracture without comminuted zone, an application of either TIFI-A or DTIFI provides significantly higher stiffness of the lateral pelvic segment than application of TIFI-C. Key words: transforaminal sacral fracture, transiliac internal fixator, dual TIFI, stability, biomechanics, digital image correlation.

• MeSH
• biomechanika MeSH
• fraktury kostí * MeSH
• interní fixátory MeSH
• kostní šrouby MeSH
• křížová kost chirurgie   MeSH
• lidé MeSH
• mechanické testy MeSH
• pánev MeSH
• pánevní kosti * diagnostické zobrazování   chirurgie   MeSH
• vnitřní fixace fraktury MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Ferritins are globular proteins with an internal cavity that enables the encapsulation of a plethora of low-mass compounds. Unfortunately, the overall negative surface charge of ferritin's internal cavity hampers efficient loading of negatively charged molecules. Therefore, we produced a genetically engineered human H-chain ferritin containing a cationic RKRK domain, reversing the natural net charge of the cavity to positive, thus allowing for efficient encapsulation of negatively charged siRNA. Due to the reversed, positive charge mediated by RKRK domains, the recombinant ferritin produced in E. coli inherently carries a load of bacterial RNA inside its cavity, turning the protein into an effective sponge possessing high affinity for DNA/RNA-binding substances that can be loaded with markedly higher efficiency compared to the wildtype protein. Using doxorubicin as payload, we show that due to its loading through the RNA sponge, doxorubicin is released in a sustained manner, with a cytotoxicity profile similar to the free drug. In summary, this is the first report demonstrating a ferritin/nucleic acid hybrid delivery vehicle with a broad spectrum of properties exploitable in various fields of biomedical applications.

• MeSH
• apoferritiny * genetika   MeSH
• doxorubicin farmakologie   chemie   MeSH
• Escherichia coli genetika   metabolismus   MeSH
• ferritiny genetika   chemie   MeSH
• lidé MeSH
• RNA * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• apoferritiny * MeSH
• doxorubicin MeSH
• ferritiny MeSH
• RNA * MeSH

Internal ribosomal entry sites (IRESs) are structured cis-acting RNAs that drive an alternative, cap-independent translation initiation pathway. They are used by many viruses to hijack the translational machinery of the host cell. IRESs facilitate translation initiation by recruiting and actively manipulating the eukaryotic ribosome using only a subset of canonical initiation factor and IRES transacting factors. Here we present cryo-EM reconstructions of the ribosome 80S- and 40S-bound Hepatitis C Virus (HCV) IRES. The presence of four subpopulations for the 80S•HCV IRES complex reveals dynamic conformational modes of the complex. At a global resolution of 3.9 Å for the most stable complex, a derived atomic model reveals a complex fold of the IRES RNA and molecular details of its interaction with the ribosome. The comparison of obtained structures explains how a modular architecture facilitates mRNA loading and tRNA binding to the P-site. This information provides the structural foundation for understanding the mechanism of HCV IRES RNA-driven translation initiation.

• Klíčová slova
• 80S ribosome, IRES RNA, cryo‐electron microscopy, internal initiation, translational control,
• MeSH
• hepatitida C metabolismus   MeSH
• IRES * MeSH
• lidé MeSH
• molekulární sekvence - údaje MeSH
• podjednotky ribozomu chemie   MeSH
• RNA virová chemie   MeSH
• sekvence aminokyselin MeSH
• sekvence nukleotidů MeSH
• simulace molekulového dockingu MeSH
• vazba proteinů MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• IRES * MeSH
• RNA virová MeSH

Exercise induced bone response although established, little is known about the molecular components that mediate bone response to mechanical loading (ML). In our recent QTL study, we identified one such possible molecular component responding to ML: cartilage oligomeric matrix protein (COMP). To address the COMP role in mediating ML effects on bone formation, COMP expression was evaluated as a function of duration and age in response to ML in female B6 mice. A 9N load was applied using a four-point bending device at 2Hz frequency for 36 cycles, once per day for 2-, 4- and 12-days on the right tibia. The left tibia was used as an internal control. Loading caused an increase in COMP expression by 1.3-, 2- and 4-fold respectively after 2-, 4- and 12-days of loading. This increase was also seen in 16 and 36-week old mice. Based on these findings, we next used COMP knockout (KO) mice to evaluate the cause and effect relationship. Quantitative analysis revealed 2 weeks of ML induced changes in vBMD and bone size in the KO mice (5.9 % and 21 % vs. unloaded bones) was not significantly different from control mice (7 % and 24 % vs. unloaded bones). Our results imply that COMP is not a key upstream mediator of the anabolic effects of ML on the skeleton.

• MeSH
• extracelulární matrix - proteiny genetika   metabolismus   MeSH
• glykoproteiny genetika   metabolismus   MeSH
• kosti a kostní tkáň fyziologie   MeSH
• lokus kvantitativního znaku MeSH
• matriliny MeSH
• mechanický stres MeSH
• myši knockoutované MeSH
• myši MeSH
• osteogeneze fyziologie   MeSH
• zatížení muskuloskeletálního systému fyziologie   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Názvy látek
• extracelulární matrix - proteiny MeSH
• glykoproteiny MeSH
• Matn1 protein, mouse MeSH Prohlížeč
• matriliny MeSH

Observation of dynamic testing by means of X-ray computed tomography (CT) and in-situ loading devices has proven its importance in material analysis already, yielding detailed 3D information on the internal structure of the object of interest and its changes during the experiment. However, the acquisition of the tomographic projections is, in general, a time-consuming task. The standard method for such experiments is the time-lapse CT, where the loading is suspended for the CT scan. On the other hand, modern X-ray tubes and detectors allow for shorter exposure times with an acceptable image quality. Consequently, the experiment can be designed in a way so that the mechanical test is running continuously, as well as the rotational platform, and the radiographic projections are taken one after another in a fast, free-running mode. Performing this so-called on-the-fly CT, the time for the experiment can be reduced substantially, compared to the time-lapse CT. In this paper, the advanced pore morphology (APM) foam elements were used as the test objects for in-situ X-ray microtomography experiments, during which series of CT scans were acquired, each with the duration of 12 s. The contrast-to-noise ratio and the full-width-half-maximum parameters are used for the quality assessment of the resultant 3D models. A comparison to the 3D models obtained by time-lapse CT is provided.

• Klíčová slova
• 4D CT, advanced pore morphology (APM) foam, compressive loading, image quality, in-situ mechanical testing, microcomputed tomography, on-the-fly tomography,
• Publikační typ
• časopisecké články MeSH

Biophysical loading of the elbow and wrist is a potential reason for chronic lesions in gymnastics and present a real concern for coaches, scientist and clinicians. Previous research has identified injury risk factors during round-off (RO) skills in elite female gymnasts. The aim of this study was to investigate key elbow and wrist joint injury risk factors during different techniques of fundamental cartwheel (CW) and RO skills performed by young female artistic gymnasts. Seventeen active young female gymnasts performed 30 successful trials of both CW and RO from a hurdle step with three different hand positions (parallel (10), T-shape (10) and reverse (10)). Synchronised kinematic (240 Hz) and kinetic (1200 Hz) data were collected for each trial. One-way repeated measures ANOVA and effect size (ES) were used for statistical analysis. The results showed statistically significant differences (P < .05) and large ES (>0.8) among hand positions for peak vertical ground reaction force (VGRF), peak elbow compression force, peak wrist compression force, elbow internal adduction moment and wrist dorsiflexion angle. In conclusion, the parallel and reverse techniques increase peak VGRF, elbow and wrist compression forces, and elbow internal adduction moment. These differences indicate that the parallel and reverse techniques may increase the potential of elbow and wrist injuries in young gymnasts compared with the T-shape technique; this is of particular importance with the high frequency of the performance of these fundamental skills.

• Klíčová slova
• 3D analysis, Biomechanics, coaching, injury and prevention, youth,
• MeSH
• biomechanika MeSH
• dítě MeSH
• gymnastika fyziologie   MeSH
• lidé MeSH
• loketní kloub fyziologie   MeSH
• poranění lokte MeSH
• poranění z opakovaného přetěžování MeSH
• poranění zápěstí MeSH
• rizikové faktory MeSH
• sportovci MeSH
• sportovní úrazy MeSH
• zápěstní kloub fyziologie   MeSH
• zatížení muskuloskeletálního systému * MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH