Ultra Compact Nanoporous Platinum Coating Improves Neural Recording

Neural electrodes are key tools for achieving a successful brain-computer interface and the electrodes should be small to minimize damage to neural tissue and obtain good spatial selectivity such as single unit recording. Here we show conventional platinum/tungsten neural probes can be coated with nanoporous Pt. Thanks to nanoporous Pt with the extremely small and uniform pores, L-2-ePt, the electrode impedance could be reduced by more than 2 orders of magnitude while the apparent area was almost the same. L-2-ePt coating enhanced neuronal recording of local field potential in monkeys, leading to facilitating implanted electrical devices in the nervous system.Peer reviewe

High Yield Sample Preconcentration Using a Highly Ion-Conductive Charge-Selective Polymer

The development and analysis of a microfluidic sample preconcentration system using a highly ion-conductive charge-selective polymer (poly-AMPS) is reported. The preconcentration is based on the phenomenon of concentration polarization which develops at the boundaries of the poly-AMPS with buffer solutions. A negatively charged polymer, poly-AMPS, positioned between two microchannels efficiently extracts cations through its large cross section, resulting in efficient anion sample preconcentration. The present work includes the development of a robust polymer that is stable over a wide range of buffers with varying chemical compositions. The sample preconcentration effect remains linear to over 3 mM (0.15 pmol) and 500 μM (15 fmol) for fluorescein and TRITC-tagged albumin solutions, respectively. The system can potentially be used for concentrating proteins on microfluidic devices with subsequent analysis for proteomic applications

Disposable Solid-State pH Sensor Using Nanoporous Platinum and Copolyelectrolytic Junction

A disposable solid-state pH sensor was realized by utilizing two nanoporous Pt (npPt) electrodes and a copolyelectrolytic junction One nanoporous Pt electrode was to measure the pH as an indicating electrode (pH-IE) and the other assembled with copolyelectrolytic junction was to maintain constant open circuit potential (E(oc)) as a solid-state reference electrode (SSRE) The copolyelectrolytic Junction was composed of cationic and anionic polymers immobilized by photo-polymerization of N,N`-methylenebisacrylamide, making buffered electrolytic environment on the SSRE It was expected to make The nanoporous Pt surrounded by a constant pH excellently worked as a solid state reference electrode so as to stabilize the system within 30 s and retain the electrochemical environment regardless of unknown sample solutions Combination between the SSRE and the pH-IE commonly based on nanoporous Pt yielded a complete solid-state pH sensor that requires no internal filling solution The solid state pH sensing chip is simple and easy to fabricate so that it could be practically used for disposable purposes Moreover the solid-state pH sensor successfully functions in calibration-free mode in a variety of buffers and surfactant samplesThis work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) (No. 2005-2001287), the Ministry of Knowledge Economy in Korea (09MC3310, Programmable Bio-CMOS Field Effect Transistors), the Korea Research Foundation Grant funded by Korea Government (MOEHRD, Basic Research Promotion Fund) (KRF-2005-075-C00021), and the Nano/Bio Science & Technology Program (M10536090001- 05N3609-00110) of the Ministry of Education, Science and Technology (MEST), Republic of Korea.Kim KB, 2010, APPL PHYS LETT, V96, DOI 10.1063/1.3389492SUSAN C, 2010, ANAL CHEM, V82, P878Guth U, 2009, J SOLID STATE ELECTR, V13, P27, DOI 10.1007/s10008-008-0574-7Han JW, 2009, JPN J APPL PHYS, V48, DOI 10.1143/JJAP.48.010205Park S, 2007, CHEM MATER, V19, P3373, DOI 10.1021/cm0710756Han JH, 2007, ELECTROANAL, V19, P786, DOI 10.1002/elan.200603772Kwon NH, 2007, ANALYST, V132, P906, DOI 10.1039/b706905gPark S, 2005, ANAL CHEM, V77, P7695, DOI 10.1021/ac050968jHa J, 2005, ANAL CHIM ACTA, V549, P59, DOI 10.1016/j.aca.2005.06.011Chun HG, 2005, ANAL CHEM, V77, P2490, DOI 10.1021/ac048535oVonau W, 2004, ELECTROCHIM ACTA, V49, P3745, DOI 10.1016/j.electacta.2004.02.048Marzouk SAM, 2003, ANAL CHEM, V75, P1258, DOI 10.1021/ac0261404Lee HJ, 1998, ANAL CHEM, V70, P3377Baur JE, 1998, J ELECTROANAL CHEM, V443, P208Suzuki H, 1998, SENSOR ACTUAT B-CHEM, V46, P104Nolan MA, 1997, ANAL CHEM, V69, P1244, DOI 10.1021/ac961020fShin JH, 1996, ANAL CHEM, V68, P3166

Frozen Cytology of Meningeal Malignant Solitary Fibrous Tumor/Hemangiopericytoma

A 51-year-old woman presented with severe dizziness. The brain magnetic resonance image revealed a 5.5 cm multiloculated mass with a thick rim in the left temporal lobe. Cytological examination of frozen diagnosis of the mass showed hypercellular sheets of round and rhabdoid cells in a hemorrhagic background, and two mitotic figures were observed. Histologically, the excised dura-based mass consisted of predominantly round cells with small foci of rhabdoid tumor cells in a pseudoalveolar pattern in a hemorrhagic background, and the cells showed nuclear positivity for signal transducer and activator of transcription 6 as well as frequent mitosis. The mass was diagnosed as a grade 3 solitary fibrous tumor (SFT)/hemangiopericytoma (HPC). The cytological diagnosis of SFT/HPC is challenging because of the heterogeneous cytological findings, such as histological heterogeneity, and because there are no standardized cytological criteria for malignant SFT/HPC. Cytological findings, such as singly scattered small cells, hypercellularity, rare ropy collagen, and round and rhabdoid cells with pseudoalveolar pattern, may assist in the diagnosis of malignant SFT/HPC

Inflammatory myofibroblastic tumor in colon

Inflammatory myofibroblastic tumor (IMT) is an uncommon mesenchymal solid tumor commonly documented in children and young adults. Here, we report a case of IMT in colon confirmed pathologically after laparoscopic anterior resection. A 35-year-old man presented with anal bleeding after defecation for 2 weeks. Colonoscopy demonstrated a mass with shallow ulceration in the central area and irregular margin accompanied by intact mucosa in the descending colon. Computer tomography showed a well-demarcated and homogenous solitary mass in the descending colon. We performed laparoscopic anterior resection. This case was diagnosed as IMT after microscopic examination. The tumor was composed of a proliferation of spindle-shaped cells arranged in the hyaline material with chronic inflammatory cells, composed mainly of plasma cells and lymphocytes. Immunohistochemically, tumor cells were positive for smooth muscle actin, and vimentin, and negative for desmin, CD117 (c-kit), anaplastic lymphoma kinase-1

Induced neural stem cells from distinct genetic backgrounds exhibit different reprogramming status

Somatic cells could be directly converted into induced neural stem cells (iNSCs) by ectopic expression of defined transcription factors. However, the underlying mechanism of direct lineage transition into iNSCs is largely unknown. In this study, we examined the effect of genetic background on the direct conversion process into an iNSC state. The iNSCs from two different mouse strains exhibited the distinct efficiency of lineage conversion as well as clonal expansion. Furthermore, the expression levels of endogenous NSC markers, silencing of transgenes, and in vitro differentiation potential were also different between iNSC lines from different strains. Therefore, our data suggest that the genetic background of starting cells influences the conversion efficiency as well as reprogramming status of directly converted iNSCs.ope

Recent Trend in the Incidence of Premalignant and Malignant Skin Lesions in Korea between 1991 and 2006

We evaluated the recent trend in the incidence of premalignant and malignant skin lesions between 1991 and 2006. Among 571,057 newly registered dermatology out-patients from our 8 affiliated university hospitals, 2,598 were diagnosed with a premalignant (899, 0.16%) or malignant skin lesions (1,699, 0.30%). Of 899 premalignant cases, 71.2% were actinic keratosis (AK), and 24.6% were Bowen's disease. Of 1,699 malignant cases, 46.2% were basal cell carcinoma, followed by squamous cell carcinoma (19.1%) and melanoma (7.1%). This 16-yr survey was divided equally into two time periods to compare the incidence of premalignant and malignant skin lesions at different time settings. Between 1991 and 1998, the incidence of cutaneous premalignancy was 0.10% which doubled during 1999-2006. For cutaneous malignancy, the incidence was 0.25% during 1991-1998 and 0.34% in 1999-2006. Incidence of AK among the new outpatients was 0.07% in 1991-1998 which staggered up to 0.15% in 1999-2006. These findings show an increase of both premalignant and malignant skin lesions, AK in particular in the dermatology outpatient-based incidence