No abstract

Conductive hydrogels are a class of composite materials that consist of hydrated and conducting polymers. Due to the mechanical similarity to biointerfaces such as human skin, conductive hydrogels have been primarily utilized as bioelectrodes, specifically neuroprosthetic electrodes, in an attempt to replace metallic electrodes by enhancing the mechanical properties and long-term stability of the electrodes within living organisms. Here, we report a conductive, smart hydrogel, which is thermoplastic and self-healing owing to its unique properties of reversible liquefaction and gelation in response to thermal stimuli. In addition, we demonstrated that our conductive hydrogel could be utilized to fabricate bendable, stretchable, and patternable electrodes directly on human skin. The excellent mechanical and thermal properties of our hydrogel make it potentially useful in a variety of biomedical applications such as electronic skin.

The decrease in signal processing speed due to increased resistance and capacitance delay resulting from aggressive miniaturisation of logic and memory devices is a major obstacle for continued down scaling of electronics. 1-3 In particular, minimizing the dimensions of interconnects -metal wires that connect different device components on the chip -is crucial for device scaling. The interconnects are isolated from each other by nonconducting or dielectric layers. Much of the recent research has focused on decreasing the resistance of scaled interconnects because integration of dielectrics using complementary metal oxide semiconductor (CMOS) compatible processes has proven to be exceptionally challenging. The key requirements for interconnect isolation materials are that they should possess low relative dielectric constants (referred to as values), serve as diffusion barriers against migration of interconnect metals such as cobalt into semiconductors and be thermally, chemically and mechanically stable. In 2005, the International Roadmap for Devices and Systems (IRDS) recommended dielectrics with -values of < 2.2 and the most recent report recommends dielectric values of ≤ 2 by 2028. 4 Despite this, state-of-the-art low- materials, such as silicon oxide derivatives, organic compounds, and aerogels exhibit  values > 2 and possess poor thermomechanical properties. 5 Here, we report a dielectric thin film with ultra-low  values of1.78 and 1.16 -close to that of air ( = 1) -at 100 kHz and 1 MHz, respectively, in amorphous boron nitride (a-BN) obtained using CMOS compatible low temperature process. We demonstrate that 3 nm thin a-BN is mechanically and electrically robust with breakdown strength of 7.3 MV/cm -exceeding requirements. Cross-sectional transmission electron microscopy reveals that a-BN is able to prevent diffusion of cobalt interconnect atoms into silicon under very harsh accelerated conditions -in contrast with

Objective: To determine the ability of MR imaging to detect the pathological changes occurring in radiofrequency (RF) thermal lesions and to assess its accuracy in revealing the extent of tissue necrosis. Materials and Methods:Using an RF electrode, thermal lesions were created in the livers of 18 rabbits. The procedure involved three phases. In the acute phase, six animals were killed the day after performing thermal ablation with RF energy, and two on day 3. In the subacute and chronic phases, eight rabbits underwent percutaneous hepatic RF ablation. After performing MR imaging, two animals were sacrificed at 1, 2, 4, and 7 weeks after the procedure, and MRpathologic correlation was performed. Results:In the acute phase, the thermal ablation lesions appeared at gross examination as well-circumscribed, necrotic areas, representing early change in the coagulative necrosis seen at microscopic examination. They were hypointense on T2-weighted images, and hyperintense on T1-weighted images. Gadolinium-enhanced MR imaging showed that a thin hyperemic rim surrounded the central coagulative necrosis. In the subacute phase, ablated lesions also showed extensive coagulative necrosis and marked inflammation at microscopic examination. Beyond two weeks, the lesions showed gradual resorption of the necrotic area, with a peripheral fibrovascular rim. The size of lesions measured by MR imaging correlated well with the findings at gross pathologic examination. Conclusion:MR imaging effectively demonstrates the histopathological tissue change occurring after thermal ablation, and accurately determines the extent of the target area.mage-guided, percutaneous ablative therapies using thermal energy sources such as radiofrequency (RF) (1 3), microwave (4) and laser (5) are rapidly evolving as minimally invasive techniques for the treatment of primary and metastatic hepatic tumors. The potential benefits of these techniques over conventional surgical options include tumor ablation in nonsurgical candidates, reduced morbidity compared with surgery, and use of the procedure on an outpatient basis (6). Preliminary clinical reports have demonstrated that hepatic RF ablation produces effective local disease control in a significant proportion of patients with nonresectable liver tumors (7 9). However, according to even the most optimistic longterm report of percutaneous RF thermal therapy in colorectal metastases, local tumors recurred in 35% of cases (10). In addition, recent studies have shown that a significant proportion of patients with hepatocellular carcinomas greater than 3 5 cm in diameter experienced local recurrence after the use of current thermal ablation strategies (11 12).

Many radiologists are unfamiliar with the recently developed World Health Organization classification scheme for neuroendocrine tumors. According to this classification scheme, neuroendocrine tumors are divided into well-differentiated endocrine tumors (carcinoids), well-differentiated endocrine carcinomas (malignant carcinoids), and poorly differentiated endocrine carcinomas on the basis of their location, histologic features, and biologic behavior. Most neuroendocrine tumors have nonspecific imaging characteristics. However, they sometimes have peculiar clinical manifestations and radiologic features, on the basis of which radiologists may infer the specific diagnosis. Neuroendocrine tumors of the gastrointestinal tract originate from the cells derived from the embryonic neural crest, neuroectoderm, and endoderm. They usually produce bioactive substances and show immunoreactivity to neuroendocrine markers. Although neuroendocrine tumors are uncommon, they should be considered in developing the differential diagnosis for gastrointestinal tumors in patients with a typical syndrome or when the tumors have characteristic imaging features.