Improved bipolar resistive switching memory characteristics in Ge0.5Se0.5 solid electrolyte by using dispersed silver nanocrystals on bottom electrode.

Resistive switching random-access memory (ReRAM) devices based on chalcogenide solid electrolytes have recently become a promising candidate for future low-power nanoscale nonvolatile memory application. The resistive switching mechanism of ReRAM is based on the formation and rupture of conductive filament (CF) in the chalcogenide solid electrolyte layers. However, the random diffusion of metal ions makes it hard to control the CF formation, which is one of the major obstacles to improving device performance of ReRAM devices. We demonstrate the spin-coated metal nanocrystals (NCs) enhance the bipolar resistive switching (BRS) memory characteristics. Compared to the Ag/Ge0.5Se0.5/Pt structure, excellent resistive switching memory characteristics were obtained from the Ag/Ge0.5Se0.5/Ag NCs/Pt structure. Ag NCs improve the uniformity of resistance values and reduce the reset voltage and current. A stable DC endurance (> 100 cycles) and a high data retention (> 10(4) sec) were achieved by spin coating the Ag NCs on the Pt bottom electrode for ReRAMs.

Granulocyte colony-stimulating factor minimizes negative remodeling of decellularized small diameter vascular graft conduits but not medial degeneration.

BACKGROUND: Poor endothelialization and intimal hyperplasia are major causes of small diameter vascular conduit (SDVC) failure. The present study was aimed to investigate the influence of granulocyte colony-stimulating factor (G-CSF) on inhibiting adverse remodeling of decellularized SDVCs. METHODS: Sprague-Dawley rats implanted with allograft infra renal abdominal aortic conduits were divided into 2 groups according to whether they were treated with G-CSF (+G-CSF group; n=6) or without (Decell group; n=6). The conduits were harvested at 8 weeks after surgery and examined for intimal hyperplasia, collagen deposition, and -actin-staining cells. The medial layer was also examined for signs of cellular repopulation and changes in the elastic fiber morphology. RESULTS: Intergroup comparison of the intimal composition showed relatively sparse collagen content and predominance of -actin-staining cells in the +G-CSF group. The medial layer in the 2 groups showed similar degrees of elastic fiber degeneration and wall thinning relative to the normal aortic wall. However, the enhanced staining for von Willebrand factor and CD31, along with transmission electron microscopy findings of superior cellular and ultrastructural preservation, suggested that the remodeling and endothelialization in the +G-CSF conduits were superior to those in the Decell conduits. CONCLUSIONS: This study suggests that G-CSF exerts a positive influence on inhibiting adverse vascular remodeling of decellularized vascular conduit implants. However, whether G-CSF administration may also effectuate an improved ability to preserve the medial structural integrity is unclear.

[Medical professionalism-on social responsibilities viewed from historical perspective].

What is medical professionalism and does it matter to the patients? Medical professionals take responsibility for their judgements and the consequences that ensue. Traditionally medical professionalism is defined as a set of values, behaviors, and relationships which support the trust the public has in doctors. The public is well aware that absence of professionalism is harmful to their interests. However, the exercise of medical professionalism is endangered by the political and cultural environment. The values of professionalism have been changed throughout the medical history and the meaning of it was also changed according to social theories. Traditional medical professionalism was based on the virtue of autonomy, self-regulation and competency etc. However, in the new millenium era, the meaning of professionalism has changed under the concept of responsibility which includes the classical virtues. The meaning of professionalism nowadays is only based on the structure and conflicting theories which cannot solve all the issues surrounding professionalism in medical practice. The conditions of medical practice are critical determinants for the future of professionalism. The interaction between doctor and patient is central to the medical care, and medical professionalism has roots in almost every aspect of medical care. I argue that doctors have responsibility to act according to the values which have been determined by the medical profession, history and surrounding society. The new millennium medical professionalism which based on the responsibility could initiate a public dialogue about the role of the doctor in creating a fairer society.

Relay kidney transplantation in Korea--legal, ethical and medical aspects.

Living kidney transplantations constitute the majority of kidney transplantations in Korea. Recently, relay kidney transplantation, which is a modified form of both 'exchange transplantation' and 'living anonymous donation', has become at issue. After a living anonymous donor makes the initial donation, the next donor, who is related to the first recipient, makes the second donation; the third donor, who is related to the second recipient, makes the third donation; and so on. In relay kidney transplantation, organ trafficking, coercion of donation, assessment order, breach of agreement, and recipient burden should be evaluated with respect to ethical, legal and medical considerations. Despite these problems, a non-governmental body, the Korean Organ and Tissue Donor Program, has been promoting relay kidney transplantations to address the shortage of cadaveric kidney donations. Acceptance of the method of relay kidney transplantation requires the institution of supplementary measures to minimize the related problems.

Comparison of success rates of orthodontic mini-screws by the insertion method.

OBJECTIVE: The aim of this study was to compare the success rates of the manual and motor-driven mini-screw insertion methods according to age, gender, length of mini-screws, and insertion sites. METHODS: We retrospectively reviewed 429 orthodontic mini-screw placements in 286 patients (102 in men and 327 in women) between 2005 and 2010 at private practice. Age, gender, mini-screw length, and insertion site were cross-tabulated against the insertion methods. The Cochran-Mantel-Haenszel test was performed to compare the success rates of the 2 insertion methods. RESULTS: The motor-driven method was used for 228 mini-screws and the manual method for the remaining 201 mini-screws. The success rates were similar in both men and women irrespective of the insertion method used. With respect to mini-screw length, no difference in success rates was found between motor and hand drivers for the 6-mm-long mini-screws (68.1% and 69.5% with the engine driver and hand driver, respectively). However, the 8-mm-long mini-screws exhibited significantly higher success rates (90.4%, p < 0.01) than did the 6-mm-long mini-screws when placed with the engine driver. The overall success rate was also significantly higher in the maxilla (p < 0.05) when the engine driver was used. Success rates were similar among all age groups regardless of the insertion method used. CONCLUSIONS: Taken together, the motor-driven insertion method can be helpful to get a higher success rate of orthodontic mini-screw placement.

Development of Specific Primer for Tricholoma matsutake.

In this study, in an effort to develop a method for the molecular detection of Tricholoma matsutake in Korea from other closely related Tricholomataceae, a species-specific PCR primer pair, TmF and TmR, was designed using nuclear ribosomal intertranscribed spacer (ITS) sequences. The DTmF and DTmR sequences were 5'-CCTGACGCCAATCTTTTCA-3' and 5'-GGAGAGCAGACTTGTGAGCA-3', respectively. The PCR primers reliably amplified only the ITS sequences of T. matsutake, and not those of other species used in this study.