Supercapacitors are capable to store relatively high amount of energy comparing to its mass. Growing number of these devices applications requires development of new testing methods. Standard methods ...of evaluation of supercapacitor parameters, as cycling voltammetry, CV, galvanostatic cycling with potential limitation, GCPL, impedance measurements, require equipment of high cost as potentiostat/galvanostat with high current efficiency. We propose a use of a power amplifier in the circuit of voltage to current converter (current driver) for supercapacitor charging/discharging in controlled conditions. The current driver is controlled by DAC output of DAQ board and voltage of DUT is measured and a control loop is realized by software. In the circuit the DC current method of evaluation of capacitance and equivalent series resistance is used. The DUT is charged and discharged with constant current and capacitance C and equivalent serial resistance ESR are calculated from voltage curves. For test purpose commercially available supercapacitors were measured with different current values. The designed test circuit is a low-cost alternative for professional and semi-professional systems. It gives several advantages as easy control of charging current and possibility of applying various current patterns.
Mitochondria play a central role in energy metabolism within the cell. Mitochondrial dysfunctions lead to various neurodegenerative disorders and to the so-called "mitochondrial diseases". A vast ...amount of evidence points to the implication of mitochondria in such complex processes as apoptosis and cardioprotection. The purpose of this review is to present a recent state of our knowledge and understanding of the action of various therapeutically applied substances on mitochondria. These include antitumor, immunosuppressant, and antiviral drugs, potassium channel openers, sulfonylureas, and anesthetics. Some of these substances are specifically designed to affect mitochondrial functions. In other cases, drugs with primary targets in other cellular locations may modify mitochondrial functions as side effects. In any case, identification of mitochondria as primary or secondary targets of a drug may help us to better understand the drug's mechanism of action and open new perspectives for its application. As far as possible, the molecular mechanisms of the interference of particular drugs in the mitochondrial metabolism will be described. In some cases, metabolic routes in which the drugs interfere will also be briefly outlined.
Hemorrhagic cystitis is a common cause of morbidity after allogeneic stem cell transplantation, frequently associated with BK virus infection. We hypothesized that patients with positive BK viruria ...before unrelated or mismatched related donor allogeneic hematopoietic stem cell transplantation have a higher incidence of hemorrhagic cystitis.
To test this hypothesis, we prospectively studied 209 patients (median age 49 years, range 19-71) with hematologic malignancies who received bone marrow (n=78), peripheral blood (n=108) or umbilical cord blood (n=23) allogeneic hematopoietic stem cell transplantation after myeloablative (n=110) or reduced intensity conditioning (n=99). Donors were unrelated (n=201) or haploidentical related (n=8).
Twenty-five patients developed hemorrhagic cystitis. Pre-transplant BK viruria detected by quantitative PCR was positive in 96 patients. The one-year cumulative incidence of hemorrhagic cystitis was 16% in the PCR-positive group versus 9% in the PCR-negative group (P=0.1). The use of umbilical cord blood or a haploidentical donor was the only significant predictor of the incidence of hemorrhagic cystitis on univariate analysis. There was also a trend for a higher incidence after myeloablative conditioning. Multivariate analysis showed that patients who had a positive PCR pre-transplant and received haploidentical or cord blood grafts with myeloablative conditioning had a significantly higher risk of developing hemorrhagic cystitis (58%) than all other recipients (7%, P<0.001).
Hemorrhagic cystitis is the result of a complex interaction of donor type, preparative regimen intensity, and BK viruria.
All organisms must replicate their genetic information accurately to ensure its faithful transmission. DNA polymerase errors provide an important source of genetic variation that can drive evolution. ...Understanding the origins of genetic variation will inform our understanding of evolution and the development of genetic diseases. A number of factors have been proposed to influence mutagenesis 1–10. Here, we used mutation accumulation lines, whole-genome sequencing, and whole-transcriptome analysis to study the locations and rate at which mutations arise in bacteria with as little selection bias as possible 11, 12. Our analysis of greater than 7,000 replication errors in over 180 sequenced lines that underwent a total of more than 370,000 generations has provided new insights into how DNA polymerase errors sculpt genetic variation and drive evolution. Homopolymer run enrichment outside of genes causes insertions and deletions in these regions. Genes encoded in the lagging strand are transcribed such that RNA polymerase and DNA polymerase collide head-on. Head-on genes have been proposed to mutate at a higher rate than genes transcribed codirectionally with DNA polymerase progression due to conflicts between transcription and DNA replication 6, 10. We did not detect associations between the number of base pair substitutions in genes and their orientation or expression. Strikingly, any higher mutation rate for head-on genes can be explained by differing sequence composition between the leading and lagging strands and the error bias for DNA polymerase in specific sequence contexts. Therefore, we find local sequence context is the major determinant of mutagenesis in bacteria.
•Intergenic regions are enriched for indels•Local sequence context strongly impacts DNA replication accuracy in vivo•Sequence context in head-on genes can lead to a higher mutation rate
Schroeder et al. show that base pair substitutions made by the replicating DNA polymerase are highly biased to specific sequence contexts. This can drive DNA polymerase to make substitutions at a higher rate in genes encoded on the lagging strand compared to genes encoded on the leading strand due to differences in their sequence composition.
•Coercivity of the SmCo5 magnets, μ0Hc≤ 4.97 T.•Impact of HDDR on the properties.•Nanostructure of the sintered magnets.
The relations between the phase recombination conditions and phase content, ...microstructure, and magnetic properties of sintered SmCo5-based permanent magnets, subjected to hydrogen treatment, were studied by X-ray diffraction, scanning electron microscopy, and magnetic hysteresis loop measurements. Recombination of the disproportionation products, SmH2±x, Co, and remains of SmCo5 phase, was carried out by heating the alloy in a vacuum to 850 °C with and without holding it for 1 h, and by heating it to 950 °С. It was shown that after recombination, the coercivity of the magnet, μ0Hc, reached the value of 4.90–4.97 T. The remnant magnetization increased from 27.7 to 43.5, and to 46.7 Am2/kg with increasing holding time during recombination from 0 to 1 h at a temperature of 850 °С, and with increased recombination temperature to 950 °C. The hysteresis loop rectangularity changed from 77 to 74.6, and to 78.8% under the same conditions.
We employed a novel technique to inspect the substrate-apposed surface of activated osteoclasts, the cells that resorb bone, in the scanning electron microscope. The surface revealed unexpected ...complexity. At the periphery of the cells were circles and crescents of individual or confluent nodules. These corresponded to the podosomes and actin rings that form a 'sealing zone', encircling the resorptive hemivacuole into which protons and enzymes are secreted. Inside these rings and crescents the osteoclast surface was covered with strips and patches of membrane folds, which were flattened against the substrate surface and surrounded by fold-free membrane in which many orifices could be seen. Corresponding regions of folded and fold-free membrane were found by transmission electron microscopy in osteoclasts incubated on bone. We correlated these patterns with the distribution of several proteins crucial to resorption. The strips and patches of membrane folds corresponded in distribution to vacuolar H+-ATPase, and frequently co-localized with F-actin. Cathepsin K localized to F-actin-free foci towards the center of cells with circular actin rings, and at the retreating pole of cells with actin crescents. The chloride/proton antiporter ClC-7 formed a sharply-defined band immediately inside the actin ring, peripheral to vacuolar H+-ATPase. The sealing zone of osteoclasts is permeable to molecules with molecular mass up to 10,000. Therefore, ClC-7 might be distributed at the periphery of the resorptive hemivacuole in order to prevent protons from escaping laterally from the hemivacuole into the sealing zone, where they would dissolve the bone mineral. Since the activation of resorption is attributable to recognition of the αVβ3 ligands bound to bone mineral, such leakage would, by dissolving bone mineral, release the ligands and so terminate resorption. Therefore, ClC-7 might serve not only to provide the counter-ions that enable proton pumping, but also to facilitate resorption by acting as a 'functional sealing zone'.
PDF
