Organic flexible memristor with reduced operating voltage and high stability by interfacial control of conductive filament growth

This work was supported in part through the BK21 Program funded by Ministry of Education of Korea.Herein, the underlying mechanisms for the growth of conductive filaments (CFs) at a metal–polymer electrolyte interface through ion migration in organic electrochemical metallization (ECM) memristor are presented. It is observed that the free volume of voids (nanopores) in the polymer electrolyte serves as the pathways of metal‐cations whereas the interfacial topography between an active electrode and a polymer electrolyte determines the nucleation sites of the CFs. The growth kinetics of the CFs and the resultant resistive memory are found to vary with the molecular weight of the polymer electrolyte and the metal protrusions at the interface. Our direct observations show that the free volume of voids of the polymer electrolyte, varied with the molecular weight, dictates the ion transport for the growth and the disruption of the CFs. Our organic ECM‐based memristor with a hetero‐electrolyte exhibits high mechanical flexibility, low switching voltages reduced by about three times compared to those of conventional devices, and stable memory retention for longer than 104 s under repeated cycles of bending.PostprintPeer reviewe

Topography-Guided Spreading and Drying of 6,13-bis(triisopropylsilylethynyl)-pentacene Solution on a Polymer Insulator for the Field-Effect Mobility Enhancement

We report on the enhancement of the field-effect mobility of solution-processed 6,13-bis(triisopropylsilylethynyl)-pentacene (TIPS-pentacene) by unidirectional topography (UT) of an inkjet-printed polymer insulator. The UT leads to anisotropic spreading and drying of the TIPS-pentacene droplet and enables to spontaneously develop the ordered structures during the solvent evaporation. The mobility of the UT-dictated TIPS-pentacene film (0.202 ± 0.012 cm2/Vs) is found to increase by more than a factor of two compared to that of the isotropic case (0.090 ± 0.032 cm2/Vs). The structural arrangement of the TIPS-pentacene molecules in relation to the mobility enhancement is described within an anisotropic wetting formalism. Our UT-based approach to the mobility enhancement is easily applicable to different classes of soluble organic field-effect transistors by adjusting the geometrical parameters such as the height, the width, and the periodicity of the UT of an inkjet-printed insulator

The Relationship between Lewis/Secretor Genotypes and Serum Carbohydrate Antigen 19-9 Levels in a Korean Population

Background : The Lewis histo-blood group system consists of 2 major antigens-Le(a) and Le(b)-and a sialyl Lewis antigen-carbohyd rate antigen (CA) 19-9. We investigated the distribution of Lewis genotypes and evaluated the relationship between the Lewis/Secretor genotypes and the serum level of CA 19-9 in a Korean population to identify whether the serum CA 19-9 levels are influenced by the Lewis/Secretor genotypes. Methods : The study included 242 individuals who had no malignancies. Lewis genotyping was performed for the 59T>G, 508G>A and 1067T>A polymorphic sites. The Secretor genotype was determined through analysis of the 357C>T and 385A>T polymorphic sites and the fusion gene. Serum CA 19-9 level was analyzed using an electrochemiluminescence immunoassay. Results : Individuals carrying the 3 common genotypes-Le/Le, Le/le(59,508), and Le/le(59,1067)-accounted for 95% of the study population. In the Korean population, the allelic frequencies of Le, Le(59)le(59,508) and le(59,1067) were 0.731, 0.010, 0.223, and 0.035, respectiveiy. We found a significant difference in serum CA 19-9 concentrations among the 9 LewislSecretor genotype groups (P<0.001). The serum CA 19-9 levels in subjects with genotype groups 1 and 2 (Le/- and se/se) were higher than those with genotype groups 3-6 (Le/- and Se/-; 15.63 vs 6.64 kU/L, P<0.001). Conclusions : Le/Le(59,508), and Le/le(59,1067) are frequent Lewis genotypes in Koreans. Because serum CA 19-9 levels are significantly influenced by the LewislSecretor genotypes, caution is suggested when interpreting the serum CA 19-9 levels. (Korean J Lab Med 2010;30:51-7)SONG SY, 2008, KOREAN J HEMATOL, V43, P34Park KU, 2005, ANN HEMATOL, V84, P656, DOI 10.1007/s00277-005-1041-5Hayashi N, 2004, PATHOBIOLOGY, V71, P26, DOI 10.1159/000072959Hamajima N, 2002, J MOL DIAGN, V4, P103HAMAJIMA N, 2002, GASTRIC CANCER, V5, P194Liu TC, 2000, ANN HEMATOL, V79, P599Lamerz R, 1999, ANN ONCOL, V10, P145Vestergaard EM, 1999, CLIN CHEM, V45, P54Liu YH, 1999, J HUM GENET, V44, P181Kim MJ, 2002, YONSEI MED J, V43, P427SHIBATA A, 2003, GASTRIC CANCER, V6, P8Liu YH, 1999, J FORENSIC SCI, V44, P82Liu YH, 1998, HUM GENET, V103, P204Pang H, 1998, HUM GENET, V102, P675Narimatsu H, 1998, CANCER RES, V58, P512Liu YH, 1996, J FORENSIC SCI, V41, P1018Koda Y, 1996, AM J HUM GENET, V59, P343Kudo T, 1996, J BIOL CHEM, V271, P9830ROUQUIER S, 1995, J BIOL CHEM, V270, P4632KELLY RJ, 1995, J BIOL CHEM, V270, P4640NISHIHARA S, 1994, J BIOL CHEM, V269, P29271MOLLICONE R, 1994, J BIOL CHEM, V269, P20987

Association of ATP7B Mutation Detection Rate with Biochemical Characteristics in Korean Patients with Wilson Disease

Wilson disease (WD) is an autosomal recessive disorder caused by mutations in the ATP7B gene, yet many patients have either one mutation, or no mutation. We investigated whether the mutation detection rate is associated with any biochemical characteristics of WD. In a study of 71 patients, we used PCR-sequencing to screen for ATP7B mutations in 7 exons (exons 8, 10, 11, 14, 15, 16, and 18) covering 95% of known mutations in Korean patients with WD. We also investigated serum concentrations of various biochemical analytes. Data were analyzed by linear association test and one-way ANOVA. Based on the number of detected ATP7B mutations, a significant difference in serum ceruloplasmin concentration was found among the 3 groups (p < 0.001). Serum ceruloplasmin concentration averaged 3.32 +/- 1.74, 10.8 +/- 5.50, and 14.9 +/- 3.88 mg/dl (mean +/- SD) in the 25, 20, and 26 patients with two, one, and no ATP7B mutations, respectively. We observed 82.9% and 16.7% of mutant allele frequency in WD patients with ceruloplasmin concentration < 10 mg/dl and 10-20 mg/dl, respectively (p < 0.001). Thus serum ceruloplasmin concentrations among WD patients differed according to the number of ATP7B mutations detected.Riordan SM, 2001, J HEPATOL, V34, P165Gow PJ, 2000, GUT, V46, P415Brewer GJ, 2009, NETH J MED, V67, P195Korman JD, 2008, HEPATOLOGY, V48, P1167, DOI 10.1002/hep.22446Mak CM, 2008, CLIN CHEM, V54, P1356, DOI 10.1373/clinchem.2008.103432Mak CM, 2008, CRIT REV CL LAB SCI, V45, P263, DOI 10.1080/10408360801991055Park S, 2007, HUM MUTAT, V28, P1108, DOI 10.1002/humu.20574Kroll CA, 2006, MOL GENET METAB, V89, P134, DOI 10.1016/j.ymgme.2006.03.008Durand F, 2001, GUT, V48, P849Yoo HW, 2002, GENET MED, V4, p43S, DOI 10.1097/01.GIM.0000040260.30727.EBSHIM H, 2003, J NUTR, V133, P1527Roberts EA, 2003, HEPATOLOGY, V37, P1475, DOI 10.1053/jhep.2003.50252Ferenci P, 2003, LIVER INT, V23, P139Cullen LM, 2003, CLIN GENET, V64, P429Seo J, 2004, J TURBUL, V5, DOI 10.1088/1468-5248/5/1/015YANG X, 2005, ZHONGHUA NEI KE ZA Z, V44, P13Brewer GJ, 2005, J HEPATOL, V42, pS13, DOI 10.1016/j.jhep.2004.11.013De Bie P, 2005, J HERED, V96, P803, DOI 10.1093/jhered/esi110CHOI JS, 2006, KOREAN J LAB MED, V26, P449Kim JH, 2006, J GASTROEN HEPATOL, V21, P588, DOI 10.1111/j.1440-1746.2005.04127.xEisenbach C, 2007, WORLD J GASTROENTERO, V13, P1711Kenney SM, 2007, HUM MUTAT, V28, P1171, DOI 10.1002/humu.20586Roberts EA, 2008, HEPATOLOGY, V47, P2089, DOI 10.1002/hep.22261Kok KF, 2008, NETH J MED, V66, P348BREWER GJ, 2009, NETH J MED, V67, P196SALLIE R, 1992, HEPATOLOGY, V16, P1206

Silicon carbide-free graphene growth on silicon for lithium-ion battery with high volumetric energy density

Silicon is receiving discernable attention as an active material for next generation lithium-ion battery anodes because of its unparalleled gravimetric capacity. However, the large volume change of silicon over charge-discharge cycles weakens its competitiveness in the volumetric energy density and cycle life. Here we report direct graphene growth over silicon nanoparticles without silicon carbide formation. The graphene layers anchored onto the silicon surface accommodate the volume expansion of silicon via a sliding process between adjacent graphene layers. When paired with a commercial lithium cobalt oxide cathode, the silicon carbide-free graphene coating allows the full cell to reach volumetric energy densities of 972 and 700 Whl(-1) at first and 200th cycle, respectively, 1.8 and 1.5 times higher than those of current commercial lithium-ion batteries. This observation suggests that two-dimensional layered structure of graphene and its silicon carbide-free integration with silicon can serve as a prototype in advancing silicon anodes to commercially viable technology.

Therapeutic Effects of Holmium-166 Chitosan Complex in Rat Brain Tumor Model

This study examined the effectiveness of Holmium-166 (Ho-166) chitosan complex therapy for a malignant glioma. Cultured C6 glioma cells (100,000 in 5 µl) were injected into the caudate/putamen of 200 - 250 gram Wistar rats. Five days later, a Ho-166 chitosan complex was injected into the same site of the glioma injection. Four injection doses were administered: the control group received PBS 10 µl, group 1 received an injection of 100 µCi (10 µl), group 2 received an injection of 50 µCi (5 µl), and group 3 received an injection of 10 µCi (1 µl). The average tumor volume for each group was 1.385 mm3 for the control group, 0.036 mm3 for group 1, 0.104 mm3 for group 2, and 0.111 mm3 for group 3. Compared with the control group, the size of the tumors in groups 1, 2 and 3 was reduced by an average of 97.4%, 92.5% and 91.9%, respectively. The Kaplan-Meier survival curve of group 2 was the longest, followed by groups 3, group 1 and the control. The mean survival was 22.8, 59, 60, and 44.6 days for the control group and groups 3, 2 and 1, respectively. H-E staining revealed that group 2 yielded the best results in the destruction of the malignant glioma. TUNEL staining and immunohistochemical studies indicated apoptotic features. The Ho-166 chitosan complex proved to be effective in destroying the malignant glioma

Assessment of Allergic Rhinitis Websites in Korea

Objectives. The internet has become an important source of medical information and a great amount of information related to allergic rhinitis (AR) is available on the internet. However, the quality of this information is still a matter of debate. Therefore, this study was conducted to assess the AR-related information on Korean websites. Methods. The key word "allergic rhinitis" was entered into 4 popular search engines, and this led to identifying 40 websites. After being categorized according to authorship, the informational value of these websites was evaluated using 4 different assessment tools such as the Journal of the American Medical Association (JAMA) benchmarks, the DISCERN questionnaire, the Allergic Rhinitis and its Impact on Asthma (ARIA) 2008 Update and the Health On the Net (HON) code. Results. The 40 websites containing AR-related information were categorized according to their authorship as Western physician: 20, Oriental physician: 14, commercial: 1, and others: 5. The mean citation frequencies of the JAMA benchmarks and the ARIA 2008 Update concepts was 1.23 out of 4 and 4.33 out of 8, respectively, while the mean DISCERN score was 1.92 out of 5. When the websites were evaluated based on the type of authorship, the mean citation frequencies of the AMA 2008 Update concepts were Western physician: 5.35, Oriental physician: 2.64. Additionally, three websites authored by Western physicians and 13 authored by Oriental physicians contained unreliable information. Among these 16 websites, only 3 websites met the requirements for the HON code "Justification". Conclusion. AR-related information available on Korean websites is of variable quality and not all of the information provided is justifiable. Thus, performing surveillance of the medical information on these websites is necessary. Furthermore, common criteria that can be used to evaluate the websites created by both Western and Oriental physicians are also needed.Bousquet J, 2008, ALLERGY, V63, P8*HLTH NET FDN, 2006, HLTH NET COD COND VESILVA LVE, 2005, BRAZILIAN J OTHORHIN, V71, P590Park HW, 2004, J KOREAN MED SCI, V19, P364Winker MA, 2000, JAMA-J AM MED ASSOC, V283, P1600Charnock D, 1999, J EPIDEMIOL COMMUN H, V53, P105Silberg WM, 1997, JAMA-J AM MED ASSOC, V277, P1244

Measurement of 129 I Radioactivity in Groundwater of Radioactive Waste Disposal Site

The investigation of the environmental radioactivity around the radioactive waste disposal site in Gyeongju is being carried out. The radioactivity of 129 I in groundwater and seaweed are to be measured. The analytical method to measure the radioactivity of 129 I in aqueous media was established. This method contains oxidation-reduction reaction, anion-exchange separation and palladium precipitation. The 129 I radioactivity in the PdI 2 precipitates was measured by using low-energy gamma spectrometer. The counts of peak at 39.6 keV of gamma energy were used for determination of 129 I radioactivity. The chemical recovery was determined by the weights of PdI 2 precipitates. The deionized water and groundwater spiked with 129 I tracer were tested. In the case of deionized water, the relative deviations of measured concentration from spiked one are from 1.1 to 10.7%. The relative deviations of measured radioactivity from spiked one in the groundwater experiments are 2.9 and 3.7%. The measured concentration is in good agreement with spiked one. The groundwater sampled from radioactive waste disposal site was tested. The concentrations of 129 I in the groundwater are below minimum detectable activities of 36.7 and 36.6 mBq/L