Brno University of Technology

About: Brno University of Technology is a education organization based out in Brno, Czechia. It is known for research contribution in the topics: Computer science & Fracture mechanics. The organization has 6339 authors who have published 15226 publications receiving 194088 citations. The organization is also known as: Vysoké učení technické v Brně & BUT.

Glomalin – Truths, myths, and the future of this elusive soil glycoprotein

Abstract: The term “Glomalin” was originally used to describe a hypothetical gene product of arbuscular mycorrhizal fungi (AMF) that was assumed to be a nearly ubiquitous, thermostable and highly recalcitrant glycoprotein, deposited in soils in large amounts, and deemed to indicate soil health and quality. It was defined operationally as the fraction of soil organic matter (SOM) extractable by a hot citrate buffer and assessed either by Bradford assay or by cross-reactivity with monoclonal antibody MAb32B11. Later, it was recognized that the extracts contained a variety of compounds, including some of non-AMF origin, cross-reactive with both Bradford assay and the monoclonal antibody. This led to re-describing the pertinent (and still only operationally defined) SOM as “glomalin-related soil proteins (GRSP)”, albeit without any substantial change in the underlying concepts. Consequently, a great deal of confusion in this area arose among researchers in soil, plant, and environmental sciences. Glomalin or GRSP (often used interchangeably) has previously been linked to various soil features, including stability of soil aggregates, size of soil C and N pools, sequestration of heavy metals, and alleviation of various plant stresses. GRSP concentrations in soil often, but not always, have been correlated with AMF biomass measured by alternative (mainly microscopic) approaches. GRSP formation, deposition, and/or decomposition in soils seem to be largely dependent on a multitude of interactions among plants, AMF, and other soil microorganisms, including prokaryotes. The chemical structure of GRSP extracted from soil remains unclear and generally complex. That is due to the unspecific mode of its extraction and purification, as well as the great variety of analytical approaches that have been used heretofore to assess it. Future research needs to elucidate the exact composition of this operationally defined SOM fraction, the controls over its production and accumulation in soils, and its exact role in soil ecology generally and soil food webs in particular. Furthermore, novel and independent tools should be established to more specifically (as compared to current glomalin assays) assess AMF biomass and functioning in roots and soil and its involvement in soil processes.

Resistive Random Access Memory Cells with a Bilayer TiO2/SiOX Insulating Stack for Simultaneous Filamentary and Distributed Resistive Switching

Abstract: In order to fulfill the information storage needs of modern societies, the performance of electronic nonvolatile memories (NVMs) should be continuously improved. In the past few years, resistive random access memories (RRAM) have raised as one of the most promising technologies for future information storage due to their excellent performance and easy fabrication. In this work, a novel strategy is presented to further extend the performance of RRAMs. By using only cheap and industry friendly materials (Ti, TiO2, SiOX, and n++Si), memory cells are developed that show both filamentary and distributed resistive switching simultaneously (i.e., in the same I–V curve). The devices exhibit unprecedented hysteretic I–V characteristics, high current on/off ratios up to ≈5 orders of magnitude, ultra low currents in high resistive state and low resistive state (100 pA and 125 nA at –0.1 V, respectively), sharp switching transitions, good cycle-to-cycle endurance (>1000 cycles), and low device-to-device variability. We are not aware of any other resistive switching memory exhibiting such characteristics, which may open the door for the development of advanced NVMs combining the advantages of filamentary and distributed resistive switching mechanisms.

Lossy / lossless floating / grounded inductance simulation using one DDCC

Abstract: In this work, we present new topologies for realizing one lossless grounded inductor and two floating, one lossless and one lossy, inductors employing a single differential difference current conveyor (DDCC) and a minimum number of passive components, two resistors, and one grounded capacitor. The floating inductors are based on ordinary dual-output differential difference cur- rent conveyor (DO-DDCC) while the grounded lossless inductor is based one a modified dual-output differential difference current conveyor (MDO-DDCC). The proposed lossless floating inductor is obtained from the lossy one by employing a negative impedance converter (NIC). The non-ideality effects of the active element on the simulated inductors are investigated. To demonstrate the perform- ance of the proposed grounded inductance simulator as an example, it is used to construct a parallel resonant circuit. SPICE simulation results are given to confirm the theoretical analysis.

Production of polyhydroxyalkanoates from cheese whey employing Bacillus megaterium CCM 2037.

Abstract: Poly(3-hydroxybutyrate) (PHB) is a polyester belonging to the family of polyhydroxyalkanoates, which accumulate in a wide variety of bacterial strains. PHB appears to be a biodegradable alternative to traditional petrochemical polymers such as polypropylene and polyethylene. In this work, we tested direct conversion of cheap waste cheese whey into PHB employing the bacterial strain Bacillus megaterium CCM 2037. Optimization of medium composition improved PHB yields about 50 fold (biomass and PHB yields 2.82 and 1.05 g l−1, respectively) as compared to none-optimized whey. Furthermore, PHB yields were improved by about 40% by introducing 1% ethanol into the medium at the beginning of the stationary phase of growth (biomass 2.87 g l−1, PHB 1.48 g l−1). According to the results of experiments carried out in Erlenmeyer flasks, B. megaterium CCM 2037 can be considered a candidate for direct PHB production from waste cheese whey. Nevertheless, experiments in laboratory-scale and semi-productive fermentors are needed to test performance under high cell density cultivation.