^(169)Yb-DTPA를 이용한 Cisternography

도종웅,김상철,이규창,이헌재,양병철,박창윤,최병숙 대한신경외과학회 1977 Journal of Korean neurosurgical society Vol.6 No.1

The radioactive nucleid cisternography is being used as a diagnostic adjunct of CSF rhinorrhea and otorrhea, hydrocephalus, patency after ventricular shunt operation, brain tumor and cangenital anomalies of the central nervous system. In numerous radioactive nucleids, ^(169)Yb-DTPA is known to have moderately effective half life, high energy level for scintilation, and pure r-emitter in subarachnoid space. Authors review some clinical advantage of cisternography using ^(169)Yb-DTPA applied in the diagnosis of CSF rhinorrhea and otorrhea, hydrocephalus, CSF fistula and patency after ventricular shunt operation.

Quantum Dot/Siloxane Composite Film Exceptionally Stable against Oxidation under Heat and Moisture

Kim, Hwea Yoon,Yoon, Da-Eun,Jang, Junho,Lee, Daewon,Choi, Gwang-Mun,Chang, Joon Ha,Lee, Jeong Yong,Lee, Doh C.,Bae, Byeong-Soo American Chemical Society 2016 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.138 No.50

<P>We report on the fabrication of a siloxane-encapsulated quantum dot (QD) film (QD-silox film), which exhibits stable emission intensity for over 1 month even at elevated temperature and humidity. QD-silox films are solidified via free radical addition reaction between oligosiloxane resin and ligand molecules on QDs. We prepare the QD-oligosiloxane resin by sol gel condensation reaction of silane precursors with QDs blended in the precursor solution, forgoing ligand-exchange of QDs. The resulting QD-oligosiloxane resin remains optically clear after 40 days of storage, in contrast to other QD-containing resins which turn turbid and ultimately form sediments. QDs also disperse uniformly in the QD-silox film, whose photoluminescence (PL) quantum yield (QY) remains nearly unaltered under harsh conditions; for example, 85 degrees C/5% relative humidity (RH), 85 degrees C/85% RH, strongly acidic, and strongly basic environments for 40 days. The QD-silox film appears to remain equally emissive even after being immersed into boiling water (100 degrees C). Interestingly, the PL QY of the QD-silox film noticeably increases when the film is exposed to a moist environment, which opens a new, facile avenue to curing dimmed QD-containing films. Given its excellent stability, we envision that the QD-silox film is best suited in display applications, particularly as a PL-type down-conversion layer.</P>

Comparison of the Haas and the Oxford classifications for prediction of renal outcome in patients with IgA nephropathy

Park, K.S.,Han, S.H.,Kie, J.H.,Nam, K.H.,Lee, M.J.,Lim, B.J.,Kwon, Y.E.,Kim, Y.L.,An, S.Y.,Kim, C.H.,Doh, F.M.,Koo, H.M.,Oh, H.J.,Kang, S.W.,Choi, K.H.,Jeong, H.J.,Yoo, T.H. W. B. Saunders Co ; Centrum Philadelphia 2014 Human pathology Vol.45 No.2

Pathologic features can provide valuable information for determining prognosis in IgA nephropathy (IgAN). However, it is uncertain whether the Oxford classification, a new classification of IgAN, can predict renal outcome better than previous ones. We conducted a retrospective cohort study in 500 patients with biopsy-proven IgAN between January 2002 and December 2010 to compare the ability of the Haas and the Oxford classifications to predict renal outcome. Primary outcome was a doubling of the baseline serum creatinine concentration (D-SCr). During a mean follow-up of 68months, 52 (10.4%) and 35 (7.0%) developed D-SCr and end-stage renal disease, respectively. There were graded increases in the development of D-SCr in the higher Haas classes. In addition, the primary endpoint of D-SCr occurred more in patients with the Oxford M and T lesions than those without such lesions. In multivariate Cox regression analyses, the Haas class V (HR, 12.19; P=.002) and the Oxford T1 (hazard ratio [HR], 6.68; P<.001) and T2 (HR, 12.16; P<.001) lesions were independently associated with an increased risk of reaching D-SCr. Harrell's C index of each multivariate model with the Haas and the Oxford classification was 0.867 (P=.015) and 0.881 (P=.004), respectively. This was significantly higher than that of model with clinical factors only (C=0.819). However, there was no difference in C-statistics between the 2 models with the Haas and the Oxford classifications (P=.348). This study suggests that the Haas and the Oxford classifications are comparable in predicting progression of IgAN.

Mean platelet volume is a prognostic factor in patients with acute kidney injury requiring continuous renal replacement therapy

Han, J.S.,Park, K.S.,Lee, M.J.,Kim, C.H.,Koo, H.M.,Doh, F.M.,Kim, E.J.,Han, J.H.,Park, J.T.,Han, S.H.,Yoo, T.H.,Kang, S.W.,Oh, H.J. Grune Stratton 2014 Journal of critical care Vol.29 No.6

Purpose: Platelet size has been demonstrated to reflect platelet activity and to predict poor clinical outcomes in patients with cardiovascular disease. However, the prognostic value of platelet size for mortality has not been studied in patients with acute kidney injury (AKI). Materials and methods: A total of 349 patients who received continuous renal replacement therapy (CRRT) for AKI between August 2009 and October 2011 were divided into 2 groups based on the median mean platelet volume (MPV) at the time of CRRT initiation. Twenty-eight-day mortality rate was determined using Kaplan-Meier plots and time-dependent receiver operating characteristic curves were constructed. In addition, multivariate Cox analysis for mortality was used to evaluate the independent prognostic value of MPV. Results: The mean age was 61.3 years, and 218 patients (62.5%) were male. At the initiation of CRRT, MPV level was inversely correlated with platelet count, whereas it was positively associated with Acute Physiology and Chronic Health Evaluation II scores. During the study period, 231 deaths (66.2%) occurred. Kaplan-Meier curve showed that 28-day all-cause mortality was significantly higher in patients with MPV ≥ 10.2 fL compared with those with MPV < 10.2 fL (P < .001). Moreover, Cox regression analysis revealed that MPV was an independent predictor for 28-day all-cause mortality after adjustment of age, age-adjusted Charlson Comorbidity Index, cause of AKI, platelet count, Acute Physiology and Chronic Health Evaluation II score, presence of malignancy, albumin, and C-reactive protein (hazard ratio, 1.080; 95% confidence interval, 1.010-1.155; P = .023). Conclusion: Mean platelet volume at the time of CRRT initiation may be an inexpensive and useful predictor for 28-day all-cause mortality in patients with AKI requiring CRRT.

Carbon contamination of EUV mask and its effect on CD performance

Lee, S.,Doh, J.G.,Lee, J.U.,Lee, I.,Jeong, C.Y.,Lee, D.G.,Rah, S.y.,Ahn, J. Elsevier 2011 Current Applied Physics Vol.11 No.4

The carbon contamination on extreme ultraviolet (EUV) masks is a critical issue causing throughput degradation and unexpected effects on imaging performance. In this work, a series of carbon contamination experiments were performed on a patterned EUV mask. The impact of carbon contamination on imaging performance was analyzed using actinic EUV coherent scattering microscopy (CSM) combined with an in-situ accelerated contamination system (ICS), which was installed on 11B EUVL beam-line at Pohang Light Source (PLS). In addition, the topography of the carbon contamination on the patterned mask was inspected with a scanning electron microscope (SEM). The mask critical dimension (CD) and reflectivity were compared before and after carbon contamination through accelerated exposure. The reflectivity degradation was measured as 5.5% after 3 h exposure which caused ∼20 nm carbon deposition. A mask CD change of 88 nm line and the space pattern showed a similar trend but different absolute values as measured by CSM and CD-SEM. This difference confirms the importance of actinic inspection technique which emulates the practical imaging condition (6<SUP>o</SUP> incident angle) as an EUV exposure tool.

Direct cation exchange of CdSe nanocrystals into ZnSe enabled by controlled binding between guest cations and organic ligands

Lee, Sooho,Yoon, Da-Eun,Kim, Dahin,Shin, Do Joong,Jeong, Byeong Guk,Lee, Dongkyu,Lim, Jaehoon,Bae, Wan Ki,Lim, Hyung-Kyu,Lee, Doh C. The Royal Society of Chemistry 2019 Nanoscale Vol.11 No.32

<P>Zn chalcogenides are suitable candidates for blue-emitting fluorophores in light-emitting devices. In particular, the efforts to grow ZnSe nanocrystals (NCs) with fine control over size and shape <I>via</I> bottom-up approaches have faced challenges because of the slow decomposition of Zn precursors. In this study, we report direct cation exchange from CdSe NCs to ZnSe. Absorption spectroscopy and density functional theory (DFT) analysis reveal that the reactivity of cation exchange depends on the degree of complexation between organic ligands and Zn halides. We controlled the binding strength of Zn complexes by changing the organic ligands and halogen species that bind with Zn. Appropriate binding strength allows for the release of Zn ions and their facile incorporation into CdSe seed NCs. Under our experimental conditions, trioctylphosphine oxide (TOPO)-ZnI2 drives the efficient cation exchange reaction whereas TOPO-ZnCl2 induces no cation exchange of CdSe NCs. In addition, functional groups vary the binding strength between Zn and ligands. Oleylamine (OLAm)-ZnI2, which has a weaker ligand-ZnI2 binding than TOPO-ZnI2, breaks down the original morphologies of host CdSe NCs due to the very fast exchange rate. On the other hand, the TOPO-ZnI2 complex induces a mild exchange rate, leading to transformation into various morphologies such as CdSe nanorods (NRs) and nanoplatelets (NPLs) into CdSe/ZnSe heterostructures inaccessible <I>via</I> other synthesis methods. The incorporation of Zn into various morphologies of CdSe results in tunable optical transitions in blue-UV regions. The synthesis of heterostructured NCs in an elongated morphology is possible, opening opportunities in photocatalysis, light emitting diodes, and luminescent solar concentrators.</P>

Charge transport-driven selective oxidation of graphene

Lee, Y.,Choi, H.,Lee, C.,Lee, H.,Goddeti, K.,Moon, S.,Doh, W.,Baik, J.,Kim, J. S.,Choi, J. Royal Society of Chemistry 2016 Nanoscale Vol.8 No.22

<P>Due to the tunability of the physical, electrical, and optical characteristics of graphene, precisely controlling graphene oxidation is of great importance for potential applications of graphene-based electronics. Here, we demonstrate a facile and precise way for graphene oxidation controlled by photoexcited charge transfer depending on the substrate and bias voltage. It is observed that graphene on TiO2 is easily oxidized under UV-ozone treatment, while graphene on SiO2 remains unchanged. The mechanism for the selective oxidation of graphene on TiO2 is associated with charge transfer from the TiO2 to the graphene. Raman spectra were used to investigate the graphene following applied bias voltages on the graphene/TiO2 diode under UV-ozone exposure. We found that under a reverse bias of 0.6 V on the graphene/TiO2 diode, graphene oxidation was accelerated under UV-ozone exposure, thus confirming the role of charge transfer between the graphene and the TiO2 that results in the selective oxidation of the graphene. The selective oxidation of graphene can be utilized for the precise, nanoscale patterning of the graphene oxide and locally patterned chemical doping, finally leading to the feasibility and expansion of a variety of graphene-based applications.</P>

Hybrid materials of upcycled Mn₃O₄ and reduced graphene oxide for a buffer layer in organic solar cells

Lee, Cheol-Ho,Lee, Sungho,Yeo, Jun-Seok,Kang, Gil-Seong,Noh, Yong-Jin,Park, Sae-Mi,Lee, Doh C.,Na, Seok-In,Joh, Han-Ik Elsevier 2018 Journal of industrial and engineering chemistry Vol.61 No.-

<P><B>Abstract</B></P> <P>Mn<SUB>3</SUB>O<SUB>4</SUB> on reduced graphene oxide (r-GO) was easily synthesized by upcycling process of wasting manganese ions which were generated during oxidation reaction from graphite to GO. The yellow-brown GO suspension under acid media before neutralization immediately became black precipitates when the suspension was titrated into the concentrated NaOH solution. The method could convert the wasting manganese ions up to ∼91wt% to Mn<SUB>3</SUB>O<SUB>4</SUB> to optimize work function in a hole transport layer (HTL) for organic solar cells. The hybrid materials exhibited an ideal electronic structure suitable for HTL, leading to the excellent power conversion efficiency of ∼3.23%.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Much amount of manganese ions are wasted during the synthesis of graphene oxide. </LI> <LI> Mn<SUB>3</SUB>O<SUB>4</SUB> particles were deposited on graphene using manganese ion wastes without any additive. </LI> <LI> Organic solar cell using Mn<SUB>3</SUB>O<SUB>4</SUB> and graphene composite shows comparable power conversion efficiency with PEDOT:PSS. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Cu+-incorporated TiO2 overlayer on Cu2O nanowire photocathodes for enhanced photoelectrochemical conversion of CO2 to methanol

Lee, Kangha,Lee, Seokwon,Cho, Hyunjin,Jeong, Sunil,Kim, Whi Dong,Lee, Sooho,Lee, Doh C. Elsevier Inc 2018 Journal of Energy Chemistry Vol.27 No.1

Thin Amorphous TiO₂ Shell on CdSe Nanocrystal Quantum Dots Enhances Photocatalysis of Hydrogen Evolution from Water

Lee, Sooho,Lee, Kangha,Kim, Whi Dong,Lee, Seokwon,Shin, Do Joong,Lee, Doh C. American Chemical Society 2014 The Journal of Physical Chemistry Part C Vol.118 No.41

<P>In this study, we designed and synthesized photocatalysts for hydrogen evolution from water by coating a thin layer of amorphous TiO<SUB>2</SUB> (<I>a</I>-TiO<SUB>2</SUB>) on CdSe nanocrystals (NCs). The thin shell of <I>a</I>-TiO<SUB>2</SUB> serves as a channel for charge carriers otherwise unutilized. Albeit a previous notion that <I>a</I>-TiO<SUB>2</SUB> is a poor photocatalyst, the enhanced photocatalytic activity in the presence of <I>a</I>-TiO<SUB>2</SUB> suggests that the material helps utilize the photogenerated charge carriers when it is in a form of thin shell on CdSe NCs. Type II band offset in CdSe/<I>a</I>-TiO<SUB>2</SUB> appears to allow the electron in the conduction band of CdSe NCs to migrate over to that of <I>a</I>-TiO<SUB>2</SUB>, and the electron participates in the hydrogen production from water. Size of CdSe NCs influences the photocatalytic hydrogen evolution rate as the energy difference between the conduction bands of semiconductors becomes larger. Electron transfer from CdSe NCs to <I>a</I>-TiO<SUB>2</SUB> layer is influenced by the level of the conduction-band edge of CdSe NCs: the size dependence indicates that electron injection to TiO<SUB>2</SUB> is facilitated with energy level offset between CdSe and TiO<SUB>2</SUB>, while smaller NCs have larger band gap and thus narrower spectral range of absorption. The interplay between charge-transfer rate and absorption cross-section should be considered in designing heterostructure NC-based photocatalysts for water splitting.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2014/jpccck.2014.118.issue-41/jp508315m/production/images/medium/jp-2014-08315m_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jp508315m'>ACS Electronic Supporting Info</A></P>