Kv3 channels contribute to the excitability of sub-populations of spinal cord neurons in lamina VII

Autonomic parasympathetic preganglionic neurons (PGN) drive contraction of the bladder during micturition but remain quiescent during bladder filling. This quiescence is postulated to be due to recurrent inhibition of PGN by fast-firing adjoining interneurons. Here, we defined four distinct neuronal types within lamina VII of the lumbosacral spinal cord, where PGN are situated, by combining whole cell patch clamp recordings with k-means clustering of a range of electrophysiological parameters. Additional morphological analysis separated these neuronal classes into parasympathetic preganglionic populations (PGN) and a fast firing interneuronal population. Kv3 channels are voltage-gated potassium channels (Kv) that allow fast and precise firing of neurons. We found that blockade of Kv3 channels by tetraethylammonium (TEA) reduced neuronal firing frequency and isolated high-voltage-activated Kv currents in the fast-firing population but had no effect in PGN populations. Furthermore, Kv3 blockade potentiated the local and descending inhibitory inputs to PGN indicating that Kv3-expressing inhibitory neurons are synaptically connected to PGN. Taken together, our data reveal that Kv3 channels are crucial for fast and regulated neuronal output of a defined population that may be involved in intrinsic spinal bladder circuits that underpin recurrent inhibition of PGN.

Analysis of Contact Reaction Phenomenon between Aluminum–Silver and p+ Diffused Layer for n-Type c-Si Solar Cell Applications

In this study, the contact mechanism between Ag–Al and Si and the change in contact resistance (Rc) were analyzed by varying the firing profile. The front electrode of an n-type c-Si solar cell was formed through a screen-printing process using Ag–Al paste. Rc was measured by varying the belt speed and peak temperature of the fast-firing furnace. Rc value of 6.98 mΩ-cm−2 was obtained for an optimal fast-firing profile with 865 °C peak temperature and 110 inches per min belt speed. The contact phenomenon and the influence of impurities between the front-electrode–Si interface and firing conditions were analyzed through scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The EDS analysis revealed that the peak firing temperature at 865 °C exhibited a low atomic weight percentage of Al (0.72 and 0.36%) because Al was involved in the formation of alloy of Si with the front electrode. Based on the optimal results, a solar cell with a conversion efficiency of 19.46% was obtained.

Study of the correlation between the composition, structure and crystallization in frits designed for single fast-firing glazes with variable BaO content

The paper presents the results of investigation on the development of frits for single fast-firing glazes with variable BaO content based on the SiO2–Al2O3–CaO–MgO–ZnO–(BaO) system, fired at a maximum temperature of 1220 °C. The study of the correlation between the composition, structure and crystallization of frits and glazes was carried out using various methods for materials characterization, including differential scanning calorimetry (DSC), dilatometry (DIL), hot-stage microscopy (HSM), X-ray diffraction and scanning and transmission electron microscopy. DSC and X-ray diffraction showed a high tendency to crystallize the tested frits. DSC curves showed that all glazes crystallized during heating in a narrow-temperature range ≈ 938–955 °C, and the introduction of BaO shifted the maximum of exothermic peaks toward higher temperatures. X-ray analysis revealed the presence of diopside and anorthite as the main crystalline phases. The introduction of 5 mass% BaO to the frit composition promoted the crystallization of the additional crystalline phase of barium feldspar (BaAl2Si2O8). In addition, in this composition a strong exothermic effect on the DSC curve at the cooling stage was observed. The analysis of data obtained from thermal studies also showed that the addition of BaO to the chemical composition of the frits resulted in a decrease in the glass transition temperature (Tg) and in reduction in viscosity calculated on the basis of the Vogel–Fulcher–Tammann equation (HSM, DIL).

Delay Timing Its and Effect on Blasting Fragmentation

Atnumbertoftsmalltscaletexperimentalttests,tsimulat ingmultiholetblaststhave tbeentperformedttotobservettheteffecttof delay timestontblasttinducedtfragmentation.tThetblaststwere performedtin thightqualitytgranodioritetblocks.tThetequilateral triangular patt- erntwastused,twithtatdistancetoft10.2cmtbetween boreholes,twhichthadtatblasttholetdiameter toft11mm,twere loadedtwith detonating cord andtthetcoupledtwithtwatertmedium. Thetdelaystusedtweretachievedtusingtdifferenttlengthstoftdetonat ingtcordtfortthe casestof delaystbetweent0tandt100tmicroseconds between holest andtatsequentialtblastingt machinetfiringtseismic detonatorstfortlargertdelays upttot4ms.tAlltfragmentstwere collectedtandt screened.t Thet experimentst revealed thattthe coarsest fragmentation wast achieved with simultaneous initiation oft allt charges.t Fragmentationt became tfiner twitht delayt time between tholest upt tot 1ms tbetween tholes.t Thet resultst showtthattinmoderatetto tcompetentt rock,t similar ttott he tgranodioritet oft the experiments,t fragmentation optimization requires delaystof tfew millisecondst pert metert oft burden.t Int viewt of tthet findings, twhich agreet witht previous published work, tthet current trendt of selecting fast firing timest for tfragmentationt optimizationtis questioned

The Acoustic Impedance and other Properties of (1-3) Piezoceramics Polymer Composite

The work is focused on an attempt to develop a route for the fabrication of piezoceamic-polymer composites having (1-3) type connectivity. The process included the extrusion of rods of diameter approximately 200 mm. A commercial piezoelectric, PC-5 was modified by addition of a lithium/bismuth based glass former together with excess PbO to lower the sintering temperature to about 1000 °C. The fast firing sintering was employed. The rods were assembled and impregnated with an epoxy resin to form 1-3 composites containing approximately 50 and 20 vol% piezoceramic. The measurement values showed that, the piezoelectric constant, d33= 232 pCN-1and 215 pCN-1, thickness electromechanical coupling coefficient, kt= 0.51 and 0.5 and the mechanical quality factor, Qm= 14 and 5 for the composites containg PZT rods at 50 vol% and 20 vol% respectively. Their acoustic impedances were 5.1 and 3.6 for the 50 vol% and 20 vol% of PZT rods respectively. The results show that with lower volume% of PZT could result in lower acoustic impedance which can be further improved for biomedical imaging and hydrophone applications.