Bulk quantities of graphene nanosheets and nanodots have been selectively fabricated by mechanical grinding exfoliation of natural graphite in a small quantity of ionic liquids. The resulting graphene sheets and dots are solvent free with low levels of naturally absorbed oxygen, inherited from the starting graphite. The sheets are only two to five layers thick. The graphene nanodots have diameters in the range of 9-29 nm and heights in the range of 1-16 nm, which can be controlled by changing the processing time.

Purpose To apply a simple and flexible manufacturing technique, two-photon polymerisation (2PP), to the fabrication of microneedle (MN) array templates with high precision and low cost in a short time. Methods Seven different MN array templates were produced by 2PP 3D printing, varying needle height (900–1300 μm), shape (conical, pyramidal, cross-shaped and with pedestal), base width (300–500 μm) and interspacing (100–500 μm). Silicone MN array moulds were fabricated from these templates and used to produce dissolving and hydrogel-forming MN arrays. These polymeric MN arrays were evaluated for their insertion in skin models and their ability to deliver model drugs (cabotegravir sodium and ibuprofen sodium) to viable layers of the skin (ex vivo and in vitro) for subsequent controlled release and/or absorption. Results The various templates obtained with 2PP 3D printing allowed the reproducible fabrication of multiple MN array moulds. The polymeric MN arrays produced were efficiently inserted into two different skin models, with sharp conical and pyramidal needles showing the highest insertion depth values (64–90% of needle height). These results correlated generally with ex vivo and in vitro drug delivery results, where the same designs showed higher drug delivery rates after 24 h of application. Conclusion This work highlights the benefits of using 2PP 3D printing to prototype variable MN array designs in a simple and reproducible manner, for their application in drug delivery.

Abstract

The ISX-A (Impurity Study Experiment) tokamak operated with major radius R =92 cm, minor radius a =26 cm, and relatively low toroidal magnetic field B T < 15 kG. 1 * 2 Only Ohmic heating was appliedo Studies of plasma confinement in this device yielded unusually favorable results in comparison with empirical scaling formulas., For example, the gross-energy-confinement times, r E = !&[/(n e T e +W|Ti)dv]/Po m E. 9 exceeded the values expected from the scaling of Jassby et at? by factors of 1-3 (lo6 average) and were larger than the values predicted by the Hugill-Sheffield formula 4 [with scaling l-l] by factors of 1.5-4.5 (3.1 average). At line-average densities (n e ) above 10 13 cm" 3 , the ISX-.A data are closest to the scaling proposed by Mirnov, 5 r E = (3 x 1(T 9 )a(cm) x/(A)« e l72 sec (n e is given in units of 10 13 cm" 3 ), although they still exceed the expectations by an average value of 1.2. Also, the maximum value of n e achieved before a major disruption occurred was 7xl0 13 cm" 3 , a factor almost 4.5 times larger than that anticipated by B T /R 0 scaling. 6 The largest values of toroidal beta, P T (0) equal to No. GA-A14133, 1976 (to be published); see also Ref" 5, above. 7 G. R. Hopkins and John M. Rawls, Nucl. Technol. 36, 171 (1977), and references contained therein. 8 P

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The traditional use of Scotch tape for exfoliating layers of two-dimensional (2D) transition metal dichalcogenides (TMDs) has been compared with a gel-assisted mechanical exfoliation technique, using MoS 2 as a representative TMD. The gel-assisted exfoliation process, which makes use of both Scotch tape and a gel film, is superior to the use of Scotch tape alone, as it gives a higher probability of obtaining larger surface area few-layer flakes. A quantitative analysis has been made between the samples prepared by the two techniques. The total density of flakes transferred onto a sample by Scotch tape alone was much higher than when using the gel film. However, most of the transferred flakes were several microns in thickness with lateral dimensions <10 µm. Therefore, the higher percentage of few-layer flakes with large lateral dimensions (> 20 µm) transferred using gel film is very advantageous. Since samples prepared using gel film have fewer flakes, the contacting of potential thin flakes on the sample can be done conveniently. Also, unlike Scotch tape, the gel film does not leave adhesive residue on the substrate. Optical microscopy, contrast difference measurements and Raman spectroscopy were used for identification of the few-layer MoS 2 flakes.

Recent experimental results for ICRF heating in PLT are presented. For the two-ion regime in D-H or 3 3 D-He plasmas minority H and He ions are found to absorb the rf power and transfer it to the deuterons and electrons in accordance with Fokker-Planck theory.

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