Biocompatible microchannel scaffold with microwires for recording regenerative peripheral nerve neural spikes

A new process for the fabrication of a microchannel scaffold with microwires for peripheral nerve applications is presented. This microchannel scaffold implemented between the ends of nerves, the axons of which regenerate through microchannel in scaffold and fixed microelectrodes. This device is entirely handcrafted using commercially available materials such as microwires, PDMS film, liquid PDMS, dental cement, and epoxy glue. This device was implemented in the a Lewis rat sciatic nerve to better analyze the electrical signals of regenerated axons. 64-electrode microchannel scaffolds were developed for both peripheral nerve interfacing and peripheral nerve regeneration. The microwires were used for recording electrode to capture neural signal from the regenerated peripheral nerves. To further differentiate the methodology, the new addition of a ribbon cable will facilitate the transmission of the electrical signals. A total of eight devices have been developed, the nerve regeneration were examined four weeks after device implantation

Assessment of various low-profile mechanical vortex generators in controlling a shock-induced separation

An experimental investigation was conducted to assess the effectiveness of five microvortex generator configurations in controlling an incident shock-induced separation associated with a 14 deg shock generator in a Mach 2.05 flow. The vortex generator configurations studied include the Ashill, Anderson, split-Anderson, trapezoidal, and ramp-vane designs. Each device height h spanned 30% of the local boundary-layer thickness d estimated just upstream of the separation for no control. An array of each control device configuration was implemented 10δ upstream of the separation location for no control. Additionally, one ramp-vane device with h/δ = 0.5 was also tested. Out of all the configurations tested, the ramp-vane device (h/δ = 0.5) shows the maximum downstream shift (21%) in separation location. This device and the split-Anderson configuration (h/δ = 0.3) both show a reduction in the maximum rms values by 26 and 24%, respectively. The study on ramp-vane devices (h/δ = 0.3, 0.5) further shows that the size of the split relative to the device height also seems to be an important parameter. For the ramp-vane devices (h/δ = 0.3, 0.5), a smaller intervane spacing of 1.7h (h/δ = 0.5) instead of 3h (h/δ = 0.3) shows a very effective control. From this perspective, providing a split size of 1h in split-Anderson device has also shown favorable result

Control of a Mach reflection-induced interaction using an array of vane-type vortex generators.

An experimental investigation was conducted to control a Mach reflection (MR)-induced flow separation in a Mach 2.05 flow using a 18∘ shock generator (SG). The study was extended to four SG exit heights (g / w) of 0.87, 0.81, 0.725, and 0.66 primarily to study its effect on the extent of flow separation as well as on Mach stem height, with and without control. Two vane-type vortex generator configurations, namely the ramp vane (RV) with device heights h/δ=0.3,0.5,0.8, and 1.0 and the rectangular vane (RRV) with h/δ=0.3 and 0.5, were studied for control. Each control device array was implemented 10δ upstream of the separation location for no control. For stable MR interactions (i.e., g/w=0.87,0.81), the extent of separation and the reattachment shock strength are seen to decrease with increase in RV height (with h/δ=1.0 device showing 17% reduction). However, for unstable MR condition (i.e., g/w=0.725), RV devices of h/δ=0.8 and 1.0 become ineffective. The RRV2 device (h/δ=0.5), on the other hand, was found to be more effective in reducing the extent of separation in both the stable (31%) and unstable (24%) MR conditions. The effectiveness of each control device is also accompanied with an increase in height of the Mach stem. This is, however, not seen as a serious limitation since in such strong interactions it is more important to prevent or avert an intake unstart condition. The separation shock unsteadiness or the σmax/Pw value, on the other hand, is seen to increase considerably with controls and seems to be almost independent for h/δ≥0.5

Control of incident shock-induced separation using vane-type vortex-generating devices.

An experimental investigation was conducted to control an incident shock-induced boundary-layer separation associated with a 14 deg shock generator in a Mach 2.05 flow. Two vane-type configurations, namely the triangular (h/δ=0.3, 0.5, 0.8, 1.0) and the rectangular (h/δ=0.5) designs, were studied. An array of each control device was tested for three control locations of X/δ=5, 10, and 15. The control location of 5δ is seen to show the maximum reduction in separation length for each device tested. For the rectangular-vane device (h/δ=0.5), a maximum reduction of 38% in separation length is observed, followed by the triangular-vane devices of h/δ=0.8 and 1.0, each of which shows a 32% reduction, and finally, h/δ=0.5 with 18%. The effectiveness of these devices to control separation is, however, seen to decrease with increase in X/δ. In terms of separation shock unsteadiness, the maximum rms value for X/δ=5δ shows the highest value for each control device, and this value decreases with increase in control location. At X/δ=15, both the rectangular vane (h/δ=0.5) and triangular vane (h/δ=0.8,1.0) show a 50% reduction in maximum rms value, whereas it decreases to 30% at X/δ=10 for these devices

Electrochemical Stripping Studies of Amlodipine Using Mwcnt Modified Glassy Carbon Electrode

The voltammetric behaviour of amlodipine was studied on multiwall carbon nanotubes (MWCNT) modified glassy carbon electrode. The oxidation of amlodipine is irreversible and exhibits a diffusion controlled process which is pH dependent. The oxidation mechanism was proposed in this work. The dependence of the current on pH, the concentration and nature of buffer, and scan rate were investigated to optimize the experimental conditions for the determination of amlodipine. Calibration plots were drawn between stripping peak current and concentration. They are linear within the range from 0.01 to 0.3 µg/mL. The lower limit of detection (LOD) was found to be very low (0.001 µg/mL) on MWCNT. The developed MWCNT modified glassy carbon electrode system was applied to successfully determine amlodipine in commercial pharmaceutical products. Key Words: Voltammetric, Multiwall Carbon Nanotubes, Amlodipine, Stripping

5-[1-(4-Meth­oxy­phen­yl)-2-nitro­but­yl]-4-phenyl-1,2,3-selenadiazole

In the title compound, C19H19N3O3Se, the selenadiazole ring is essentially planar (r.m.s. deviation = 0.001 Å). The heterocyclic ring makes dihedral angles of 50.2 (2) and 76.3 (9)°, respectively, with the meth­oxy­phenyl and phenyl rings

5-(2-Nitro-1-phenyl­but­yl)-4-phenyl-1,2,3-selenadiazole

In the title compound, C18H17N3O2Se, the selenadiazole ring is planar [maximum deviation = 0.012 (2) Å for the ring C atom bearing the phenyl substituent]. The dihedral angle between the selenadiazole ring and the attached benzene ring is 46.5 (1)°. There is one short intra­molecular C—H⋯Se contact

Utilization of sodium montmorillonite clay for enhanced electrochemical sensing of amlodipine

Nanosize surface of sodium montmorillonite has been prepared via sonication and deposited on glassy carbon electrodes for use as working electrode in a highly sensitive electrochemical biosensor for the detection of trace amounts of the calcium channel blocking drug, amlodipine. The cyclic voltammetric behaviour of amlodipine is studied in the pH range of 1.0−13.0. In alkali medium (pH 13.0) the sensor shows good response. Cyclic voltammograms show one oxidation peak and one broad reduction peak, which may be due to the oxidation of secondary amino group and reduction of chlorine and nitro groups respectively. Plots of log peak current and potential when correlated with log scan rate, indicate irreversible electron diffusion controlled redox reaction. The optimum conditions have been established by differential pulse stripping voltammetry. The anodic peak current is linear with concentration of the analyte at optimum conditions; the detection limit has been determined to be 0.01 mg/mL. A simple, sensitive and time-saving differential pulse stripping voltammetric procedure has been developed for estimation of amlodipine in its formulations as tablets

1-(2-Naphth­yl)-3-phenyl-3-(4,5,6,7-tetra­hydro-1,2,3-benzoselenadiazol-4-yl)propan-1-one

In the title compound, C25H22N2OSe, the fused six-membered cyclo­hexene ring of the 4,5,6,7-tetra­hydro-1,2,3-benzoselenadiazole group adopts a near half-chair conformation and the five-membered 1,2,3-selenadiazole ring is essentially planar (r.m.s. deviation = 0.004 Å). There are weak inter­molecular C—H⋯O and C—H⋯π inter­actions in the crystal structure. Inter­molecular π–π stacking is also observed between the naphthyl units, with a centroid–centroid distance of 3.529 (15) Å