Single-crystal silicon planar micro-spikes with protruding barbs are developed for micro-scale biopsy and the feasibility of using the micro-spike as a micro-scale biopsy tool is evaluated for the first time. The fabrication process utilizes a deep silicon etch to define the micro-spike outline, resulting in protruding barbs of various shapes. Shanks of the fabricated micro-spikes are 3 mm long, 100 µm thick and 250 µm wide. Barbs protruding from micro-spike shanks facilitate the biopsy procedure by tearing off and retaining samples from target tissues. Micro-spikes with barbs successfully extracted tissue samples from the small intestines of the anesthetized pig, whereas micro-spikes without barbs failed to obtain a biopsy sample. Parylene coating can be applied to improve the biocompatibility of the micro-spike without deteriorating the biopsy function of the micro-spike. In addition, to show that the biopsy with the micro-spike can be applied to tissue analysis, samples obtained by micro-spikes were examined using immunofluorescent staining. Nuclei and F-actin of cells which are extracted by the micro-spike from a transwell were clearly visualized by immunofluorescent staining.

Poloxamer is a potentially suitable material for an injectable IOL. Further study is needed.

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Command coordination and tactical effectiveness in counterinsurgency operations: lessons from the South Korean campaignThis article systematically analyzes the causes of combat effectiveness of the South Korean security forces through the course of its various counter-insurgency (COIN) operations from 1948 to 1953. We argue that improvements in two interrelated aspects ultimately resulted in higher level of performance at the operational and tactical level: unified operational command structure and the subsequent improvements in tactical efficiency under the guidance of the US advisory mission. We analyze the key factors that influenced the overall performance of the South Korea's COIN operations by examining four incidents/crises that occurred from 1948 to 1953: the Jeju Island Uprising, Yeo-Soon Rebellion, Chiri Mountain operations (1948)(1949)(1950), and Operation RATKILLER. Through an in-depth case study on how a nascent army improved its capacity in combating homegrown insurgencies, we demonstrate how the actual conduct of operations itself remains just as significant in the assessment of overall COIN outcomes.

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This paper reports fabrication results of silicon retinal tacks and preliminary test results of siliconmicromachined retinal tacks. It is mainly intended to fix a stimulating microelectrode array, which is a part of the implantable artificial retina system. Although conventional retinal tacks made of titanium are widely used, they are expensive, invasive and restricted in shape. Also, glues could cause degeneration of inner retina and fibrin formation. Silicon micromachining technology, based on semiconductor manufacturing, can produce retinal tacks in a mass. Furthermore, the tack is easily shaped and the shapes are highly reproducible. Various types of retina tacks are proposed and fabricated. Ex vivo experiment was done in enucleated porcine eyes and in vivo experiment was done in rabbit eyes. There were some points to be improved, but we found that the silicon tack was useful and could be a good candidate as the substitute for the conventional titanium tack.