Feasibility of a Hybrid Brain-Computer Interface for Advanced Functional Electrical Therapy

We present a feasibility study of a novel hybrid brain-computer interface (BCI) system for advanced functional electrical therapy (FET) of grasp. FET procedure is improved with both automated stimulation pattern selection and stimulation triggering. The proposed hybrid BCI comprises the two BCI control signals: steady-state visual evoked potentials (SSVEP) and event-related desynchronization (ERD). The sequence of the two stages, SSVEP-BCI and ERD-BCI, runs in a closed-loop architecture. The first stage, SSVEP-BCI, acts as a selector of electrical stimulation pattern that corresponds to one of the three basic types of grasp: palmar, lateral, or precision. In the second stage, ERD-BCI operates as a brain switch which activates the stimulation pattern selected in the previous stage. The system was tested in 6 healthy subjects who were all able to control the device with accuracy in a range of 0.64–0.96. The results provided the reference data needed for the planned clinical study. This novel BCI may promote further restoration of the impaired motor function by closing the loop between the “will to move” and contingent temporally synchronized sensory feedback

Influence of degradation of parent-material and welded joints on the integrity of the breeches pipe located at pipeline iii of hydro power plant ‘Perućica’

Hydro power plant ’Perućica’, which comprises 7 hydroelectric generating units, each with installed power of 330 MW, is the oldest hydro power plant in Montenegro and was put in service in 1960. This high pressure hydro power plant is a complex hydroenergetic system, which consists of a 3335 m long concrete tunnel, surge with a broadening and overflow and three steel pipelines with two-sided Pelton turbines with horizontal shafts installed.Five turbines have nominal power of 38 MW, while two have nominal power of 58,5 MW (307 MW overall). The biggest problem at hydro power plant ’Perućica’ refers to the parent material and weld metal of the breeches pipe 1A located at pipeline III. Significantly lesser problems were detected at parent material and weld metal of breeches pipes 7B, 8A and 8B. Pipeline and breeches pipes were made of microalloyed steel ’Nioval 47’ (steel mill ’Jesenice’). Stresses that occur at pipelines in service during the process of execution of functional tasks (stationary and dynamic loads) and during the disturbed process of exploitation (non-stationary dynamic loads) cause severe damaging of parent material and weld metal at structural components of breeches pipes (collars and anchors), thus endangering the integrity of pipeline structure as a whole. Role of the collar, which enables the leaning of the breeches pipe on the foundation, is to receive static and dynamic loads (mean pressure of up to 61 bar in pipeline axis, specific load that occurs due to the quantity of water in the pipeline, action of the force of gravity) and displacements which happen due to non-stationary dynamic loads that occur at the pipeline, while the anchor strengthens and balances the mass of the breeches pipe. In this paper the results of non-destructive tests carried out on parent material and weld metal (collar and anchor) of breeches pipes with designations 1A, 7A, 8A and 8B and results of destructive tests performed on parent material of the anchor are presented. Tests that were carried out include visual testing (VT), magnetic particle testing (MT) and ultrasonic testing (UT), while destructive tests included determination of chemical composition, tensile properties, impact energy and hardness. On the basis of results of test results it was determined that the main cause of occurrence of significant damages (degradation of parent material of the anchor and weld metal between the collar and anchor, as well as between the pipeline and the anchor) at the structure of the breeches pipe 1A of the pipeline III at the hydro power plant ’Perućica’ is the fact that the breeches pipe did not lean on the collar, as was predicted by design, but on the anchor which, due to the size of its cross-section, could not endure all loads that occur at the breeches pipe during service. Damages that occurred on parent material and weld metal of breeches pipes 7B, 8A and 8B are directly caused by flaws in welding technology and conditions of exploitation. Executed researches showed that degradation of parent material and weld metal does not influence the integrity of the pipeline III as a whole

Influence of degradation of parent-material and welded joints on the integrity of the breeches pipe located at pipeline iii of hydro power plant ‘Perućica’

Hydro power plant ’Perućica’, which comprises 7 hydroelectric generating units, each with installed power of 330 MW, is the oldest hydro power plant in Montenegro and was put in service in 1960. This high pressure hydro power plant is a complex hydroenergetic system, which consists of a 3335 m long concrete tunnel, surge with a broadening and overflow and three steel pipelines with two-sided Pelton turbines with horizontal shafts installed.Five turbines have nominal power of 38 MW, while two have nominal power of 58,5 MW (307 MW overall). The biggest problem at hydro power plant ’Perućica’ refers to the parent material and weld metal of the breeches pipe 1A located at pipeline III. Significantly lesser problems were detected at parent material and weld metal of breeches pipes 7B, 8A and 8B. Pipeline and breeches pipes were made of microalloyed steel ’Nioval 47’ (steel mill ’Jesenice’). Stresses that occur at pipelines in service during the process of execution of functional tasks (stationary and dynamic loads) and during the disturbed process of exploitation (non-stationary dynamic loads) cause severe damaging of parent material and weld metal at structural components of breeches pipes (collars and anchors), thus endangering the integrity of pipeline structure as a whole. Role of the collar, which enables the leaning of the breeches pipe on the foundation, is to receive static and dynamic loads (mean pressure of up to 61 bar in pipeline axis, specific load that occurs due to the quantity of water in the pipeline, action of the force of gravity) and displacements which happen due to non-stationary dynamic loads that occur at the pipeline, while the anchor strengthens and balances the mass of the breeches pipe. In this paper the results of non-destructive tests carried out on parent material and weld metal (collar and anchor) of breeches pipes with designations 1A, 7A, 8A and 8B and results of destructive tests performed on parent material of the anchor are presented. Tests that were carried out include visual testing (VT), magnetic particle testing (MT) and ultrasonic testing (UT), while destructive tests included determination of chemical composition, tensile properties, impact energy and hardness. On the basis of results of test results it was determined that the main cause of occurrence of significant damages (degradation of parent material of the anchor and weld metal between the collar and anchor, as well as between the pipeline and the anchor) at the structure of the breeches pipe 1A of the pipeline III at the hydro power plant ’Perućica’ is the fact that the breeches pipe did not lean on the collar, as was predicted by design, but on the anchor which, due to the size of its cross-section, could not endure all loads that occur at the breeches pipe during service. Damages that occurred on parent material and weld metal of breeches pipes 7B, 8A and 8B are directly caused by flaws in welding technology and conditions of exploitation. Executed researches showed that degradation of parent material and weld metal does not influence the integrity of the pipeline III as a whole

A decision support system for electrode shaping in multi-pad FES foot drop correction

Background: Functional electrical stimulation (FES) can be applied as an assistive and therapeutic aid in the rehabilitation of foot drop. Transcutaneous multi-pad electrodes can increase the selectivity of stimulation; however, shaping the stimulation electrode becomes increasingly complex with an increasing number of possible stimulation sites. We described and tested a novel decision support system (DSS) to facilitate the process of multi-pad stimulation electrode shaping. The DSS is part of a system for drop foot treatment that comprises a customdesigned multi-pad electrode, an electrical stimulator, and an inertial measurement unit. Methods: The system was tested in ten stroke survivors (3-96 months post stroke) with foot drop over 20 daily sessions. The DSS output suggested stimulation pads and parameters based on muscle twitch responses to short stimulus trains. The DSS ranked combinations of pads and current amplitudes based on a novel measurement of the quality of the induced movement and classified them based on the movement direction (dorsiflexion, plantar flexion, eversion and inversion) of the paretic foot. The efficacy of the DSS in providing satisfactory pad-current amplitude choices for shaping the stimulation electrode was evaluated by trained clinicians. The range of paretic foot motion was used as a quality indicator for the chosen patterns. Results: The results suggest that the DSS output was highly effective in creating optimized FES patterns. The position and number of pads included showed pronounced inter-patient and inter-session variability; however, zones for inducing dorsiflexion and plantar flexion within the multi-pad electrode were clearly separated. The range of motion achieved with FES was significantly greater than the corresponding active range of motion (p < 0.05) during the first three weeks of therapy. Conclusions: The proposed DSS in combination with a custom multi-pad electrode design covering the branches of peroneal and tibial nerves proved to be an effective tool for producing both the dorsiflexion and plantar flexion of a paretic foot. The results support the use of multi-pad electrode technology in combination with automatic electrode shaping algorithms for the rehabilitation of foot drop.The research has been supported in part by grants of the Basque Government (PI2013-10), the ERA-NET EU/MINECO project (INDIGO-DBT2-051) and by the Ministry of Education, Science and Technological Development of Serbia (Project no. 175016)

Jednostavan matematički model: još jedan način da se objasne hemijske ravnoteže u vodenim rastvorima

Hemijske ravnoteže, jedan od najvažnijih koncepata u hemiji, predstavljaju svojevrstan izazov za srednjoškolske nastavnike. Stoga je potrebno posvetiti dodatnu pažnju iznalaženju što većeg broja pristupa čiji je konačni cilj najviši stepen razumevanja ovog gradiva od strane učenika. Hidrolizu soli i puferske sisteme, kao relativno kompleksne primere ravnoteža u vodenim rastvorima, učenici veoma često ne razumeju na suštinskom nivou, tako da im i izrada računskih zadataka iz ovih oblasti predstavlja teškoću. Upravo su računski zadaci autorima ovog rada poslužili za demonstraciju modela kojim se, primenom jednostavnih matematičkih operacija, predavačima pruža još jedna mogućnost da pomenute nastavne sadržaje dodatno približe učenicima. Naime, osnovna ideja je da se svaka ravnoteža, bilo da je reč o hidrolizi, puferima ili još kompleksnijim ravnotežama u vodenim rastvorima (npr. ugljen-dioksid-karbonatna-bikarbonatna ravnoteža), prikaže u standardnom matematičkom obliku količnika, koji se dalje množi odgovarajućim pomoćnim izrazima: [H+]/[H+]=1 i/ili [OH-]/[OH-]=1 (čije su konačne vrednosti 1). Na ovaj način se, u proširenom izrazu za posmatranu hemijsku ravnotežu, obezbeđuje pojavljivanje konstanti, kao što su jonski proizvod vode i/ili odgovarajuća konstanta kiselosti/baznosti. Iako se ovakav pristup naizgled može učiniti kao „dodatno komplikovanje već dovoljno komplikovanog problema“, važno je imati na umu da se ovakvim sistemom rešavanja zadataka favorizuje ponavljanje (i utvrđivanje) elementarnih pojmova: jonski proizvod vode, konstanta disocijacije, acido-bazne ravnoteže. Dosledno ponavljanje ovih pojmova uz inkorporaciju pomenutog matematičkog modela, kod učenika može da proizvede suštinsko razumevanje gradiva i da im pomogne u rešavanju računskih zadataka, kao što su izračunavanje pH-vrednosti vodenih rastvora hemijskih vrsta koje hidrolizuju i određivanje pH-vrednosti pufera, bez potrebe pamćenja bilo kakvih matematičkih formula. Takođe, opisani matematički model učenicima može biti koristan tokom usvajanja novih koncepata iz različitih prirodnih nauka, budući da je metoda množenja bilo kojeg izraza drugim, pomoćnim izrazom (čija je konačna vrednost 1) univerzalno primenljiva.Usmeno saopštenje je, od strane Nebojše Radovića, predstavljeno drugog dana konferencije, 25.04.2024. godine.Abstract: [https://cherry.chem.bg.ac.rs/handle/123456789/6485

Jednostavan matematički model: još jedan način da se objasne hemijske ravnoteže u vodenim rastvorima

Hemijske ravnoteže, jedan od najvažnijih koncepata u hemiji, predstavljaju svojevrstan izazov za srednjoškolske nastavnike. Stoga je potrebno posvetiti dodatnu pažnju iznalaženju što većeg broja pristupa čiji je konačni cilj najviši stepen razumevanja ovog gradiva od strane učenika. Hidrolizu soli i puferske sisteme, kao relativno kompleksne primere ravnoteža u vodenim rastvorima, učenici veoma često ne razumeju na suštinskom nivou, tako da im i izrada računskih zadataka iz ovih oblasti predstavlja teškoću. Upravo su računski zadaci autorima ovog rada poslužili za demonstraciju modela kojim se, primenom jednostavnih matematičkih operacija, predavačima pruža još jedna mogućnost da pomenute nastavne sadržaje dodatno približe učenicima. Naime, osnovna ideja je da se svaka ravnoteža, bilo da je reč o hidrolizi, puferima ili još kompleksnijim ravnotežama u vodenim rastvorima (npr. ugljen-dioksid-karbonatna-bikarbonatna ravnoteža), prikaže u standardnom matematičkom obliku količnika, koji se dalje množi odgovarajućim pomoćnim izrazima: [H+]/[H+]=1 i/ili [OH-]/[OH-]=1 (čije su konačne vrednosti 1). Na ovaj način se, u proširenom izrazu za posmatranu hemijsku ravnotežu, obezbeđuje pojavljivanje konstanti, kao što su jonski proizvod vode i/ili odgovarajuća konstanta kiselosti/baznosti. Iako se ovakav pristup naizgled može učiniti kao „dodatno komplikovanje već dovoljno komplikovanog problema“, važno je imati na umu da se ovakvim sistemom rešavanja zadataka favorizuje ponavljanje (i utvrđivanje) elementarnih pojmova: jonski proizvod vode, konstanta disocijacije, acido-bazne ravnoteže. Dosledno ponavljanje ovih pojmova uz inkorporaciju pomenutog matematičkog modela, kod učenika može da proizvede suštinsko razumevanje gradiva i da im pomogne u rešavanju računskih zadataka, kao što su izračunavanje pH-vrednosti vodenih rastvora hemijskih vrsta koje hidrolizuju i određivanje pH-vrednosti pufera, bez potrebe pamćenja bilo kakvih matematičkih formula. Takođe, opisani matematički model učenicima može biti koristan tokom usvajanja novih koncepata iz različitih prirodnih nauka, budući da je metoda množenja bilo kojeg izraza drugim, pomoćnim izrazom (čija je konačna vrednost 1) univerzalno primenljiva.Usmeno saopštenje je, od strane Nebojše Radovića, predstavljeno drugog dana konferencije, 25.04.2024. godine.Presentation: [https://cherry.chem.bg.ac.rs/handle/123456789/6486

Far infrared properties of sintered PbTe doped with boron

Far infrared spectra of sintered PbTe doped with boron were analyzed. The measured infrared spectra were fitted using a modified plasmon-phonnon interaction model with two additional oscillators (at about 195 cm-1 and 285 cm-1) representing local B-impurity modes. The obtained results were compared with previously published data for a single crystal PbTe sample doped with boron

Curcumin loaded pegylated nanoemulsions designed for maintained antioxidant effects and improved bioavailability: A pilot study on rats

The current study describes the experimental design guided development of PEGylated nanoemulsions as parenteral delivery systems for curcumin, a powerful antioxidant, as well as the evaluation of their physicochemical characteristics and antioxidant activity during the two years of storage. Experimental design setup helped development of nanoemulsion templates with critical quality attributes in line with parenteral application route. Curcumin-loaded nanoemulsions showed mean droplet size about 105 nm, polydispersity index <0.15, zeta potential of −40 mV, and acceptable osmolality of about 550 mOsm/kg. After two years of storage at room temperature, all formulations remained stable. Moreover, antioxidant activity remained intact, as demonstrated by DPPH (IC50 values 0.078–0.075 mg/mL after two years) and FRAPS assays. In vitro release testing proved that PEGylated phospholipids slowed down the curcumin release from nanoemulsions. The nanoemulsion carrier has been proven safe by the MTT test conducted with MRC-5 cell line, and effective on LS cell line. Results from the pharmacokinetic pilot study implied the PEGylated nanoemulsions improved plasma residence of curcumin 20 min after intravenous administration, compared to the non-PEGylated nanoemulsion (two-fold higher) or curcumin solution (three-fold higher). Overall, conclusion suggests that developed PEGylated nanoemulsions present an acceptable delivery system for parenteral administration of curcumin, being effective in preserving its stability and antioxidant capacity at the level highly comparable to the initial findings

Far infrared properties of sintered PbTe doped with boron

Far infrared spectra of sintered PbTe doped with boron were analyzed. The measured infrared spectra were fated using a modified plasmon-phonnon interaction model with two additional oscillators (at about 195 cm(-1) and 285 cm(-1)) representing local B-impurity modes. The obtained results were compared with previously published data for a single crystal PbTe sample doped with boron