• Title/Summary/Keyword: nanopore

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Nanopore Generation in Low Dielectric Organosilicate and SiCOH Thin Films

  • Heo, Kyu-Young;Yoon, Jin-Hwan;Jin, Kyeong-Sik;Jin, Sang-Woo;Oh, Kyoung-Suk;Choi, Chi-Kyu;Ree, Moon-Hor
    • Proceedings of the Polymer Society of Korea Conference
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    • 2006.10a
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    • pp.298-298
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    • 2006
  • There has been much interest in incorporating nanoscale voids into dielectric materials in order to reduce their k value, and thus in producing low-k porous interdielectric materials. One approach to the development of low-k dielectric materials is the templated polycondensation of organosilicate precursors in the presence of a thermally labile, organic polymeric porogen. The other is SiOCH films have low dielectric constant as well as good mechanical strength and high thermal stability through PECVD. In this article we explore the nanopore generation mechanism of organosilicate film using star-shape porogen and SiOCH film using bis-trimethylsilylmethane (BTMSM) precursor.

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Determining Potential Link between Environmental and Clinical Isolates of Cryptococcus neoformans/Cryptococcus gattii Species Complexes Using Phenotypic and Genotypic Characterisation

  • Kenosi Kebabonye;Mosimanegape Jongman;Daniel Loeto;Sikhulile Moyo;Wonderful Choga;Ishmael Kasvosve
    • Mycobiology
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    • v.51 no.6
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    • pp.452-462
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    • 2023
  • Opportunistic infections due to Cryptococcus neoformans and C. gattii species complexes continue to rise unabated among HIV/AIDS patients, despite improved antifungal therapies. Here, we collected a total of 20 environmental and 25 presumptive clinical cryptococcal isolates from cerebrospinal fluid (CSF) samples of 175 patients enrolled in an ongoing clinical trial Ambition 1 Project (Botswana-Harvard Partnership). Identity confirmation of the isolates was done using MALDI-TOF MS and PCR. We describe the diversity of the isolates by PCR fingerprinting and sequencing (Oxford Nanopore Technology) of the intergenic spacer region. Mating types of the isolates were determined by amplification of the MAT locus. We report an unusual prevalence of 42.1% of C. neoformans × C. deneoformans hybrids Serotype AD (n = 16), followed by 39.5% of C. neoformans Serotype A (n = 15), 5.3% of C. deneoformans, Serotype D (n = 2), 7.9% of C. gattii (n = 3), and 5.3% of C. tetragattii (n = 2) in 38 representative isolates that have been characterized. Mating type-specific PCR performed on 38 representative environmental and clinical isolates revealed that 16 (42.1%) were MATa/MAT𝛼 hybrids, 17 (44.7%) were MAT𝛼, and five (13.2%) possessed MATa mating type. We used conventional and NGS platforms to demonstrate a potential link between environmental and clinical isolates and lay a foundation to further describe mating patterns/history in Botswana.

Whole genome sequencing analysis on antibiotic-resistant Escherichia coli isolated from pig farms in Banten Province, Indonesia

  • Hadri Latif;Debby Fadhilah Pazra;Chaerul Basri;I Wayan Teguh Wibawan;Puji Rahayu
    • Journal of Veterinary Science
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    • v.25 no.3
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    • pp.44.1-44.13
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    • 2024
  • Importance: The emergence and rapid increase in the incidence of multidrug-resistant (MDR) bacteria in pig farms has become a serious concern and reduced the choice of effective antibiotics. Objective: This study analyzed the phylogenetics and diversity of antibiotic resistance genes (ARGs) and molecularly identified the source of ARGs in antibiotic-resistant Escherichia coli isolated from pig farms in Banten Province, Indonesia. Methods: Forty-four antibiotic-resistant E. coli isolates from fecal samples from 44 pig farms in Banten Province, Indonesia, were used as samples. The samples were categorized into 14 clusters. Sequencing was performed using the Oxford Nanopore Technologies MinION platform, with barcoding before sequencing with Nanopore Rapid sequencing gDNA-barcoding (SQK-RBK110.96) according to manufacturing procedures. ARG detection was conducted using ResFinder, and the plasmid replicon was determined using PlasmidFinder. Results: Three phylogenetic leaves of E. coli were identified in the pig farming cluster in Banten Province. The E. coli isolates exhibited potential resistance to nine classes of antibiotics. Fifty-one ARGs were identified across all isolates, with each cluster carrying a minimum of 10 ARGs. The ant(3'')-Ia and qnrS1 genes were present in all isolates. ARGs in the E. coli pig farming cluster originated mainly from plasmids, accounting for an average of 89.4%. Conclusions and Relevance: The elevated potential for MDR events, coupled with the dominance of ARGs originating from plasmids, increases the risk of ARG spread among bacterial populations in animals, humans, and the environment.

Hybrid Inverted Organic Solar Cells Using Nanoimprinted $TiO_2$ (Nanoimprinting 방법으로 제작된 나노 기공 $TiO_2$를 이용한 복합 유기 태양전지의 특성 분석)

  • Baek, Woon-Hyuk;Yoon, Tae-Sik;Lee, Hyun-Ho;Kim, Yong-Sang
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.1068_1069
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    • 2009
  • $TiO_2$의 계면적을 넓힘으로써 태양전지의 특성을 향상시키기 위해 정렬도가 높은 나노 기공 (nanopore, NP) 이산화티타늄 ($TiO_2$)을 이용하여 복합 태양전지를 제작하였다. Polymethyl methacrylate (PMMA)를 사용한 nanoimprinting lithography (NIL) 기술을 이용하여 NP $TiO_2$를 제작하였으며. 광활성층으로는 poly(3-hexylthiophene) (P3HT)와 [6,6]-phenyl $C_{61}$ butyric acid methyl ester (PCBM)을 사용하였다. NP $TiO_2$를 이용한 태양전지의 전력변환효율이 1.49%로 표면이 고른 소자의 효율인 1.18%에 비해 26% 가량 증가하였다. 이와 같은 효율 향상의 원인은 $TiO_2$와 광활성층의 계면이 증가되어 전하의 생성과 분리가 용이해졌기 때문인 것으로 사료된다.

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Formation of Anodized GaN Nanopores on InGaN/GaN Multi-quantum Well Structures (InGan/GaN 다중양자우물구조 위에 제작되어진 산화된 GaN 나노구멍)

  • Choi, Jae-Ho;Kim, Keun-Joo;Jung, Mi;Woo, Deok-Ha
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.11a
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    • pp.315-316
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    • 2006
  • We fabricated GaN nanopores m the etching process of anodic oxidation of aluminum. The aluminum was deposited by using E-beam evaporator on p-type GaN. After the aluminum was anodized GaN structure was exposed to the electric field with the oxidat species. The fabricated nanopore structure provides the enhanced intensity of light emission at the wavelengths 470 nm. We investigated the structure of the GaN nanopores from FE-SEM and EDS measurements.

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Nanostructures of diblock copolymers under curved confinement

  • Shin, Kyu-Soon;Huh, June;Jo Won-Ho;Xiang hongqi;McCarthy Thomas J.;Russell Thomas P.
    • Proceedings of the Polymer Society of Korea Conference
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    • 2006.10a
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    • pp.294-294
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    • 2006
  • Diblock copolymers whose morphology in the bulk is dictated by the volume fraction of the components and segmental interactions were confined within nanoscopic cylindrical pores. Since the confining geometry is nonplanar and nanoscopic, the extreme imposed curvature, comparable to molecular dimensions, places significant packing frustration on the chains. When incommensurability between the repeating period of diblock copolymers and the diameter of nanopore is coupled with the curvature, it causes the marked departures from bulk or even thin film behavior. The entropy penalty from the constraints and the curvature of the physical confinement determines unique nanostructures available only with this curved confinement.

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Regulation of Electrochemical Oxidation of Glucose by lonic Strength-Controlled Virtual Area of Nanoporous Platinum Electrode

  • Kim, Jong-Won;Park, Se-Jin
    • Journal of the Korean Electrochemical Society
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    • v.10 no.3
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    • pp.203-206
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    • 2007
  • Electrochemical reaction of glucose was regulated by the electrochemically active area of nanoporous platinum, which is controlled by ionic strength. The profile of the oxidation current of glucose vs. ionic strength was identical with that of the electrochemically active area. This result confirms that the nanopores are virtually opened for the electrochemical reaction of glucose when the ionic strength climbs over a specific concentration and implies that the electrochemical reactions on nanoporous electrode surfaces can be controlled by concentration of electrolyte.

Distinct Mechanisms of DNA Sensing Based on N-Doped Carbon Nanotubes with Enhanced Conductance and Chemical Selectivity

  • Kim, Han Seul;Lee, Seung Jin;Kim, Yong-Hoon
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.415.1-415.1
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    • 2014
  • Carrying out first-principles calculations, we study N-doped capped carbon nanotube (CNT) electrodes applied to DNA sequencing. While we obtain for the face-on nucleobase junction configurations a conventional conductance ordering where the largest signal results from guanine according to its high highest occupied molecular orbital (HOMO) level, we extract for the edge-on counterparts a distinct conductance ordering where the low-HOMO thymine provides the largest signal. The edge-on mode is shown to operate based on a novel molecular sensing mechanism that reflects the chemical connectivity between N-doped CNT caps that can act both as electron donors and electron acceptors and DNA functional groups that include the hyperconjugated thymine methyl group[1].

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Preparation and Atomic Force Microscopy (AFM) Characterization of DNA Scaffolds as a Template for Protein Immobilization

  • Kim, Hyeran;Lee, Hyun Uk;Lee, Jouhahn
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.411.2-411.2
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    • 2014
  • The design of DNA nanostructures is of fundamental importance, the intrinsic value of DNA as a building-block material lies in its ability to organize other bio-molecules with nanometer-scale spacing. Here, we report the fabrication of DNA scaffolds with nano-pores (<10 nm size) that formed easily without the use of additives (i.e., avidin, biotin, polyamine, or inorganic materials) into large-scale structures by assembling DNA molecules at near room temperature ($30^{\circ}C$) and low pH (~5.5). Protein immobilization results also confirmed that a fibronectin (FN) proteins/large scale DNA scaffolds/aminopropylytriethoxysilane (APS)/SiO2/Si substrate with high sensitivity formed in a well-defined manner. The DNA scaffolds can be applied for use with DNA-based biochips, biophysics, and cell biology.

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