Three-dimensional nanoprinting via charged aerosol jets.

Three-dimensional (3D) printing1-9 has revolutionized manufacturing processes for electronics10-12, optics13-15, energy16,17, robotics18, bioengineering19-21 and sensing22. Downscaling 3D printing23 will enable applications that take advantage of the properties of micro- and nanostructures24,25. However, existing techniques for 3D nanoprinting of metals require a polymer-metal mixture, metallic salts or rheological inks, limiting the choice of material and the purity of the resulting structures. Aerosol lithography has previously been used to assemble arrays of high-purity 3D metal nanostructures on a prepatterned substrate26,27, but in limited geometries26-30. Here we introduce a technique for direct 3D printing of arrays of metal nanostructures with flexible geometry and feature sizes down to hundreds of nanometres, using various materials. The printing process occurs in a dry atmosphere, without the need for polymers or inks. Instead, ions and charged aerosol particles are directed onto a dielectric mask containing an array of holes that floats over a biased silicon substrate. The ions accumulate around each hole, generating electrostatic lenses that focus the charged aerosol particles into nanoscale jets. These jets are guided by converged electric-field lines that form under the hole-containing mask, which acts similarly to the nozzle of a conventional 3D printer, enabling 3D printing of aerosol particles onto the silicon substrate. By moving the substrate during printing, we successfully print various 3D structures, including helices, overhanging nanopillars, rings and letters. In addition, to demonstrate the potential applications of our technique, we printed an array of vertical split-ring resonator structures. In combination with other 3D-printing methods, we expect our 3D-nanoprinting technique to enable substantial advances in nanofabrication.

Tailoring the Orientation and Periodicity of Wrinkles Using Ion-Beam Bombardment.

The present study demonstrates that surface reformation in polydimethylsiloxane can be controlled using ion-beam (IB) irradiation. This can be done by simply varying the IB incidence angle and requires no change in the energy source. By controlling the incidence angle of IB irradiation, we were able to continuously control the pattern of the wrinkle structure, that is, a randomly formed pattern or an anisotropic one. Moreover, the directional characteristics of the wrinkle pattern control the alignment of liquid crystal molecules. This control is a function of the incidence angle of the IB. These simple methods can provide considerable flexibility in the fabrication of wrinkle structures.

[A case of jeujunogastric intussusception presented with hematemesis after distal gastrectomy].

Adult intussusception represents 5% of all cases of intussusception and accounts for only 1-5% intestinal obstructions. Intussusception is a rare complication after gastric surgery with an incidence estimated at 0.1%. Early diagnosis of the acute onset intussusception is critical because mortality rates increase abruptly with delay in surgical treatment. We present here a case of jejunogastric intussusception diagnosed by gastroscopy in a patient with a history of distal gastrectomy due to early gastric cancer who had experienced hematemesis.

[Comparison of the cut direction between gross finding, streoscopic finding, and pathologic mapping of endoscopic submucosal dissection Specimen].

BACKGROUND/AIMS: The correct pathologic review is very important after endoscopic submucosal dissection. The cut direction of specimen should be the right angle of the closest area between the lesion and the lateral margin for the correct pathologic review. The aim of this study was to evaluate the concordance of the gross finding and stereoscopic finding compared to the pathologic mapping in the setting of the cut direction. METHODS: Between December 2008 and May 2009, the objects were 48 specimens in 46 patients who were diagnosed with early gastric cancer and high grade adenoma after endoscopic submucosal dissection. The specimens were stained with hematoxylin and observed by the stereoscopy and analyzed by the image analysis system. The cut direction was divided by an angle of 45 degree based on the oral side of the specimen, and the cut directions of the gross finding, the stereoscopic finding, and the pathologic finding were compared. RESULTS: The concordance of the gross finding in the setting of the cut direction was 68% (33/48), and the kappa value was 0.626, and the concordance of the stereoscopic finding in the setting of the cut direction was 87% (33/48), and the kappa value was 0.874. The accuracy of the gross finding was significantly lower than that of the stereoscopic finding in the setting of the cut direction (p<0.05). CONCLUSIONS: The endoscopist needs the careful observation and close attention in the setting of the cut direction of the specimen by gross finding, and stereoscopic analysis may be a useful tool for decision of the cut direction.

Control of the wrinkle structure on surface-reformed poly(dimethylsiloxane) via ion-beam bombardment.

We investigated the surface reformation of poly(dimethylsiloxane) (PDMS) elastomers by means of ion beam bombardment for fabricating wrinkle structures. Oxidation on the PDMS surface formed a silica-like outer layer that interacted with the inner PDMS layer, leading to the formation of wrinkle structures that minimized the combined bending energy of the outer layer and stretching energy of the inner layer. In addition, we controlled the amplitude and period of the wrinkle structures by adjusting the PDMS annealing temperature. As the PDMS annealing temperature was increased, the amplitude and period of the wrinkles formed by IB irradiation changed from 604.35 to 69.01 nm and from 3.07 to 0.80 µm, respectively.

Homogeneous self-aligned liquid crystals on wrinkled-wall poly(dimethylsiloxane) via localised ion-beam irradiation.

We demonstrate self-aligned liquid crystals (LCs) using a wrinkled-wall polydimethylsiloxane (PDMS) wrinkle structure, which is a key factor to obtain a stable homogeneous alignment state with positive LCs. We constructed the wrinkled walls via localised surface exposure to IB radiation, which passed through a long length localised pattern mask. The creation of the wrinkled wall helped to align the LC molecules homogeneously because the wrinkled wall acted as a guide for the arrangement of positive LC molecules. In addition, we confirmed the stability of the alignment state as the width of the wrinkled wall was changed. Although this wrinkled-wall method is a non-contact method, LC alignment is achieved via an anisotropic topographical guide, which provides the LC molecules with stable homogeneous alignment.

[A case of the ruptured splenic artery aneurysm treated with transcatheter embolization].

Splenic artery aneurysms are the most common visceral artery aneurysms, which are usually found incidentally. The most common complication of splenic artery aneurysms is spontaneous rupture into the peritoneal cavity, which leads to acute peritonitis and shock. Less commonly, it may rupture directly into the stomach, small bowel or pancreatic duct and may present with acute gastrointestinal hemorrhage. We report a rare case of the ruptured splenic artery aneurysm, presenting as acute massive hematochezia which was treated with transcatheter embolization.