| 1. |
- Jeon, Jae Bum, et al.
(författare)
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Photo-annealed amorphous titanium oxide for perovskite solar cells
- 2019
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Ingår i: Nanoscale. - : Royal Society of Chemistry. - 2040-3364 .- 2040-3372. ; 11:41, s. 19488-19496
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Tidskriftsartikel (refereegranskat)abstract
- Electron selective layers are important to the efficiency, stability and hysteresis of perovskite solar cells. Photo-annealing is a low-cost, roll-to-roll-compatible process that can be applied to the post-treatment fabrication of sol-gel based metal oxide layers. Here, we fabricate an amorphous titanium oxide electron selective layer at a low temperature in a dry atmosphere using a UV light annealing system and compare it with a thermal annealing process. Active oxygen species are created by using UV light to promote hydrolysis and condense the TiO2 precursor, which removes organic ligands effectively. The photo-annealed TiO2-based perovskite solar cell has a power conversion efficiency of 19.37% without hysteresis.
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| 2. |
- Kim, Byeong Jo, et al.
(författare)
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High-Efficiency Flexible Perovskite Solar Cells Enabled by an Ultrafast Room-Temperature Reactive Ion Etching Process
- 2020
-
Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 12:6, s. 7125-7134
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Tidskriftsartikel (refereegranskat)abstract
- Perovskite solar cells (PSCs), which have surprisingly emerged in recent years, are now aiming at commercialization. Rapid, low-temperature, and continuous fabrication processes that can produce high-efficiency PSCs with a reduced fabrication cost and shortened energy payback time are important challenges on the way to commercialization. Herein, we report a reactive ion etching (RIE) method, which is an ultrafast room-temperature technique, to fabricate mesoporous TiO2 (mp-TiO2) as an electron transport layer for high-efficiency PSCs. Replacing the conventional high-temperature annealing process by RIE reduces the total processing time for fabricating 20 PSCs by 40%. Additionally, the RIE-processed mp-TiO2 exhibits enhanced electron extraction, whereupon the optimized RIE-mp-TiO2-based PSC exhibits a power conversion efficiency (PCE) of 19.60% without J–V hysteresis, when the devices were optimized with a TiCl4 surface treatment process. Finally, a flexible PSC employing RIE-mp-TiO2 is demonstrated with 17.29% PCE. Considering that the RIE process has been actively used in the semiconductor industry, including for the fabrication of silicon photovoltaic modules, the process developed in this work could be easily applied toward faster, simpler, and cheaper manufacturing of PSC modules.
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| 3. |
- Lee, Sunjae, et al.
(författare)
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Dysregulated signaling hubs of liver lipid metabolism reveal hepatocellular carcinoma pathogenesis
- 2016
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Ingår i: Nucleic Acids Research. - : Oxford University Press (OUP). - 0305-1048 .- 1362-4962. ; 44:12, s. 5529-5539
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Tidskriftsartikel (refereegranskat)abstract
- Hepatocellular carcinoma (HCC) has a high mortality rate and early detection of HCC is crucial for the application of effective treatment strategies. HCC is typically caused by either viral hepatitis infection or by fatty liver disease. To diagnose and treat HCC it is necessary to elucidate the underlying molecular mechanisms. As a major cause for development of HCC is fatty liver disease, we here investigated anomalies in regulation of lipid metabolism in the liver. We applied a tailored network-based approach to identify signaling hubs associated with regulation of this part of metabolism. Using transcriptomics data of HCC patients, we identified significant dysregulated expressions of lipid-regulated genes, across many different lipid metabolic pathways. Our findings, however, show that viral hepatitis causes HCC by a distinct mechanism, less likely involving lipid anomalies. Based on our analysis we suggest signaling hub genes governing overall catabolic or anabolic pathways, as novel drug targets for treatment of HCC that involves lipid anomalies.
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| 4. |
- Lee, SangWook, et al.
(författare)
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Fabrication and mechanical properties of suspended one-dimensional polymer nanostructures: polypyrrole nanotube and helical polyacetylene nanofibre
- 2006
-
Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 17, s. 992-996
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Tidskriftsartikel (refereegranskat)abstract
- Mechanical properties of suspended quasi-one-dimensional polymer nanostructures were investigated using atomic force microscopy (AFM). A recently developed new acid-free etch method combined with electron beam lithography was used to fabricate suspended polypyrrole (PPy) nanotubes and helical polyacetylene (HPA) nanofibres. The elastic modulus of each suspended structure was obtained by AFM force–distance measurements. The estimated modulus value of the PPy nanotube (HPA nanofibre) was 0.96 GPa (0.5 GPa). Using this acid-free method, all-organic flexible NEMS devices can be fabricated in the future.
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| 5. |
- Ugawa, Masashi, et al.
(författare)
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Reduced acoustic resonator dimensions improve focusing efficiency of bacteria and submicron particles
- 2022
-
Ingår i: Analyst. - : Royal Society of Chemistry (RSC). - 1364-5528. ; 147:2, s. 274-281
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we demonstrate an acoustofluidic device that enables single-file focusing of submicron particles and bacteria using a two-dimensional (2D) acoustic standing wave. The device consists of a 100 μm × 100 μm square channel that supports 2D particle focusing in the channel center at an actuation frequency of 7.39 MHz. This higher actuation frequency compared with conventional bulk acoustic systems enables radiation-force-dominant motion of submicron particles and overcomes the classical size limitation (≈2 μm) of acoustic focusing. We present acoustic radiation force-based focusing of particles with diameters less than 0.5 μm at a flow rate of 12 μL min−1, and 1.33 μm particles at flow rates up to 80 μL min−1. The device focused 0.25 μm particles by the 2D acoustic radiation force while undergoing a channel cross-section centered, single-vortex acoustic streaming. A suspension of bacteria was also investigated to evaluate the biological relevance of the device, which demonstrated the alignment of bacteria in the channel at aflow rate of up to 20 μL min−1. The developed acoustofluidic device can align submicron particles within a narrow flow stream in a highly robust manner, validating its use as a flow-through focusing chamber to perform high-throughput and accurate flow cytometry of submicron objects
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| 6. |
- Yu, H.Y., et al.
(författare)
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Current enhancement with alternating gate voltage in the Coulomb blockade regime of a single wall carbon nanotube
- 2004
-
Ingår i: Applied Physics A. - : Springer Science and Business Media LLC. - 0947-8396 .- 1432-0630. ; 79, s. 1613-1615
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the current–voltage characteristics of a carbon nanotube in a single electron transistor structure with alternating gate voltage. A continuous current enhancement effect with increasing frequency of the applied gate voltage up to 13 MHz is reported. Assuming that I=nef, more than 1000 electrons are driven to flow across the source–drain channel at VDS=100 mV, 13 MHz of gate voltage (Vp-p=2 V) and T=1.8 K. The continuous current enhancement is explained by the broadening effect of the discrete energy levels of the finite-length carbon nanotube.
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| 7. |
- Jeong, Heesu, et al.
(författare)
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Room-Temperature-Grown amorphous Indium-Tin-Silicon-Oxide thin film as a new electron transporting layer for perovskite solar cells
- 2022
-
Ingår i: Applied Surface Science. - : Elsevier. - 0169-4332 .- 1873-5584. ; 581
-
Tidskriftsartikel (refereegranskat)abstract
- We report the amorphous quaternary oxide, indium-tin-silicon-oxide (ITSO), thin film as a new electron transport layer (ETL) for perovskite solar cells (PSCs). ITSO thin films are grown by magnetron co-sputtering indium-tin-oxide (ITO) and silicon oxide (SiO2) on commercial transparent conducting oxide (TCO) thin films at room temperature. As Si content increases (0-53.8 at%) the optical bandgap increases by approximately 1.3 eV and the electrical resistivity increases by six orders mainly because of the carrier concentration decrease. Consequently, the ITSO electronic structure depends largely on Si content. PSCs employing ITSO thin films as ETLs were fabricated to evaluate the effect of Si content on device performances. Si content influenced the shunt and series resistance. The optimized device was obtained using an ITSO film with 33.0 at% Si content, exhibiting 14.50% power-conversion efficiency. These results demonstrate that ITSO films are promising for developing efficient PSCs by optimizing the growing process and/or In/Sn/Si/O compositions. This approach can reduce PSC manufacturing process time and costs if ITO and ITSO are grown together by continuous sequential sputtering in a dual gun (ITO and SiO2) chamber.
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| 8. |
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| 9. |
- Jhang, SungHo, et al.
(författare)
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Random telegraph noise in carbon nanotubes and peapods
- 2006
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Ingår i: Current Applied Physics. - : Elsevier BV. - 1567-1739. ; 6, s. 987-991
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Tidskriftsartikel (refereegranskat)abstract
- The switching of resistance between two discrete values, known as random telegraph noise (RTN), was observed in individual single-walled carbon nanotubes (SWNTs) and C60-filled SWNTs (the so-called peapods). The RTN has been studied as a function of bias-voltage and gate-voltage as well as temperature. By analyzing the features of the RTN, we identify three different types of RTN existing in the SWNT related systems. While the RTN can be generated by the various charge traps in the vicinity of the SWNTs, the RTN for metallic SWNTs is mainly due to reversible defect motions between two metastable states, activated by inelastic scattering with ballistic electrons. On the other hand, the noise for peapods can be attributed to the motion of C60 molecules in hollow space of SWNTs.
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| 10. |
- Lee, DongSu, et al.
(författare)
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Extraction of semiconducting carbon nanotubes by repeated dielectrophoretic filtering
- 2005
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Ingår i: Applied Physics A. - : Springer Science and Business Media LLC. - 0947-8396 .- 1432-0630. ; 80, s. 5-8
-
Tidskriftsartikel (refereegranskat)abstract
- We have separated semiconducting carbon nanotubes from as-grown batch material (HiPco production). A special configuration of electrodes which generates a 3-dimensional electric field gradient was used to filter out and deposit metallic carbon nanotubes by the dielectrophoretic method, leaving the remaining dispersion enriched in semiconducting nanotubes. The efficiency of filtering was determined by Raman spectroscopy. Using repeated deposition cycles, the ratio of semiconducting to metallic tubes was increased. After seven cycles, the proportion of semiconducting tubes in the remaining dispersion reached 94%.
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| 11. |
- Lee, DongSu, et al.
(författare)
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Fabrication of crossed junctions of semiconducting and metallic carbon nanotubes: A CNT-gated CNT-FET
- 2006
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Ingår i: Journal of nanoscience and Nanotechnology. - : American Scientific Publishers. - 1533-4880 .- 0000-0000. ; 6, s. 1325-1330
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Tidskriftsartikel (refereegranskat)abstract
- We have developed a method to fabricate crossed junctions between semiconducting (s) and metallic (m) carbon nanotubes (CNTs) combining electric field directed chemical vapor deposition growth and dielectrophoretic alignment. By separating the s- and m-CNTs with a thin dielectric an ultrasmall field effect transistor (FET) was fabricated. By using the m-CNT as a gate it was possible to modulate the source-drain current through the s-CNT FET channel. We have also used the m-CNT as an electrical lead. An off-state current lowering was observed when the m-CNT lead was used as a drain electrode.
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| 12. |
- Lee, Minho, et al.
(författare)
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Thermal-assisted photo-annealed TiO2 thin films for perovskite solar cells fabricated under ambient air
- 2020
-
Ingår i: Applied Surface Science. - : ELSEVIER. - 0169-4332 .- 1873-5584. ; 530
-
Tidskriftsartikel (refereegranskat)abstract
- We report herein a facile process for the fabrication of amorphous TiO2 thin films under ambient atmosphere using thermal-assisted UV-annealing (similar to 125 degrees C). The TiO2 films were prepared via spin-coating titanium diisopropoxide bis(acetylacetonate) precursor and sequential photo-annealing at various temperatures. Additional soft annealing during the UV-annealing altered the surface chemical states and electrical band structures of the amorphous TiO2 films. The UV-annealing at room temperature leads to a higher conduction band minimum level of the film and a smaller amount of hydroxyl group at the film surface, compared to the thermal-assisted (100-250 degrees C) UV-annealing or the thermal-only annealing (500 degrees C). Effects of the temperature during the UV-annealing process on photovoltaic properties were investigated by fabricating planar heterojunction perovskite cells with methylammonium lead triiodide under ambient atmosphere. At higher temperature of 100-150 degrees C, compared to room temperature, fill factor and power conversion efficiency were enhanced, and hysteresis in current-voltage curves were reduced. Impedance analysis demonstrates that the capacitance is significantly reduced, leading to suppressed hysteresis of the perovskite solar cells. Finally, we achieved a power-conversion efficiency of 20.36% (for the reverse scan) and a stabilized power output of 18.57% from a 125 degrees C -photo-annealed TiO2-based device.
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| 13. |
- Lee, SangWook, et al.
(författare)
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A three-terminal carbon nanorelay
- 2004
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Ingår i: Nano letters. - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 4:10, s. 2027-2030
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Tidskriftsartikel (refereegranskat)abstract
- Three-terminal nanorelay structures were fabricated with multiwall carbon nanotubes (MWNTs). The nanotube relays were deflected by applying a gate voltage until contact (mechanical and/or electrical) was made with a drain electrode, thus closing the circuit. It was possible to achieve multiple switching cycles, showing that carbon nanotubes are suitable and practical systems for developing nanoelectromechanical devices of this kind.
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| 14. |
- Lee, SangWook, et al.
(författare)
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Network analyses identify liver-specific targets for treating liver diseases
- 2017
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Ingår i: Molecular Systems Biology. - : EMBO. - 1744-4292. ; 13:8
-
Tidskriftsartikel (refereegranskat)abstract
- We performed integrative network analyses to identify targets that can be used for effectively treating liver diseases with minimal side effects. We first generated co-expression networks (CNs) for 46 human tissues and liver cancer to explore the functional relationships between genes and examined the overlap between functional and physical interactions. Since increased de novo lipogenesis is a characteristic of nonalcoholic fatty liver disease (NAFLD) and hepatocellular carcinoma (HCC), we investigated the liver-specific genes co-expressed with fatty acid synthase (FASN). CN analyses predicted that inhibition of these liver-specific genes decreases FASN expression. Experiments in human cancer cell lines, mouse liver samples, and primary human hepatocytes validated our predictions by demonstrating functional relationships between these liver genes, and showing that their inhibition decreases cell growth and liver fat content. In conclusion, we identified liver-specific genes linked to NAFLD pathogenesis, such as pyruvate kinase liver and red blood cell (PKLR), or to HCC pathogenesis, such as PKLR, patatin-like phospholipase domain containing 3 (PNPLA3), and proprotein convertase subtilisin/kexin type 9 (PCSK9), all of which are potential targets for drug development.
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| 15. |
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| 16. |
- Nemeno-Guanzon, J. G., et al.
(författare)
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Trends in Tissue Engineering for Blood Vessels
- 2012
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Ingår i: Journal of Biomedicine and Biotechnology. - : Hindawi Limited. - 1110-7243 .- 1110-7251. ; 2012, s. article ID 956345-
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Forskningsöversikt (refereegranskat)abstract
- Over the years, cardiovascular diseases continue to increase and affect not only human health but also the economic stability worldwide. The advancement in tissue engineering is contributing a lot in dealing with this immediate need of alleviating human health. Blood vessel diseases are considered as major cardiovascular health problems. Although blood vessel transplantation is the most convenient treatment, it has been delimited due to scarcity of donors and the patient's conditions. However, tissue-engineered blood vessels are promising alternatives as mode of treatment for blood vessel defects. The purpose of this paper is to show the importance of the advancement on biofabrication technology for treatment of soft tissue defects particularly for vascular tissues. This will also provide an overview and update on the current status of tissue reconstruction especially from autologous stem cells, scaffolds, and scaffold-free cellular transplantable constructs. The discussion of this paper will be focused on the historical view of cardiovascular tissue engineering and stem cell biology. The representative studies featured in this paper are limited within the last decade in order to trace the trend and evolution of techniques for blood vessel tissue engineering.
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| 17. |
- Park, Jeewoong, et al.
(författare)
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Acousto-microfluidics for screening of ssDNA aptamer
- 2016
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
-
Tidskriftsartikel (refereegranskat)abstract
- We demonstrate a new screening method for obtaining a prostate-specific antigen (PSA) binding aptamer based on an acoustofluidic separation (acoustophoreis) technique. Since acoustophoresis provides simultaneous washing and separation in a continuous flow mode, we efficiently obtained a PSA binding aptamer that shows high affinity without any additional washing step, which is necessary in other screening methods. In addition, next-generation sequencing (NGS) was applied to accelerate the identification of the screened ssDNA pool, improving the selecting process of the aptamer candidate based on the frequency ranking of the sequences. After the 8 th round of the acoustophoretic systematic evolution of ligands by exponential enrichment (SELEX) and following sequence analysis with NGS, 7 PSA binding ssDNA aptamer-candidates were obtained and characterized with surface plasmon resonance (SPR) for affinity and specificity. As a result of the new SELEX method with PSA as the model target protein, the best PSA binding aptamer showed specific binding to PSA with a dissociation constant (K d) of 0.7 nM.
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| 18. |
- Uhlén, Mathias, et al.
(författare)
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A pathology atlas of the human cancer transcriptome
- 2017
-
Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 357:6352, s. 660-
-
Tidskriftsartikel (refereegranskat)abstract
- Cancer is one of the leading causes of death, and there is great interest in understanding the underlying molecular mechanisms involved in the pathogenesis and progression of individual tumors. We used systems-level approaches to analyze the genome-wide transcriptome of the protein-coding genes of 17 major cancer types with respect to clinical outcome. A general pattern emerged: Shorter patient survival was associated with up-regulation of genes involved in cell growth and with down-regulation of genes involved in cellular differentiation. Using genome-scale metabolic models, we show that cancer patients have widespread metabolic heterogeneity, highlighting the need for precise and personalized medicine for cancer treatment. All data are presented in an interactive open-access database (www.proteinatlas.org/pathology) to allow genome-wide exploration of the impact of individual proteins on clinical outcomes.
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| 19. |
- Zhang, Cheng, et al.
(författare)
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Investigating the Combinatory Effects of Biological Networks on Gene Co-expression
- 2016
-
Ingår i: Frontiers in Physiology. - : Frontiers Media. - 1664-042X. ; 7
-
Tidskriftsartikel (refereegranskat)abstract
- Co-expressed genes often share similar functions, and gene co-expression networks have been widely used in studying the functionality of gene modules. Previous analysis indicated that genes are more likely to be co-expressed if they are either regulated by the same transcription factors, forming protein complexes or sharing similar topological properties in protein-protein interaction networks. Here, we reconstructed transcriptional regulatory and protein-protein networks for Saccharornyces cerevisiae using well-established databases, and we evaluated their co-expression activities using publically available gene expression data. Based on our network-dependent analysis, we found that genes that were co-regulated in the transcription regulatory networks and shared similar neighbors in the protein-protein networks were more likely to be co-expressed. Moreover, their biological functions were closely related.
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| 20. |
- Aryapratama, Rio, et al.
(författare)
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Performance evaluation of hollow fiber air gap membrane distillation module with multiple cooling channels
- 2016
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Ingår i: Desalination. - : Elsevier BV. - 0011-9164. ; 385, s. 58-68
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Tidskriftsartikel (refereegranskat)abstract
- The hollow fiber air gap membrane distillation (AGMD) module equipped with the multiple cooling channels network made of stainless steel was developed. The performance of the developed AGMD module was evaluated by conducting several experiments, including the effect of feed temperature and flow rate, ratio of membrane surface area to condensation surface area, membrane packing position, comparison with hollow fiber DCMD, and the effect of inner and outer module channels to process performance. Moreover, theoretical model was suggested for the multiple cooling channels module. This study reveals that the produced flux and thermal efficiency of this module were up to 12.5 kg/m2 h and 81.7%, respectively, which is higher than most of previous studies that used polymeric fibers as coolant channels. Furthermore, the optimum ratio of membrane area to condensation surface area to produce optimum flux and thermal efficiency is known to be around 0.55. Further experimental results show that the outer channel has significant contribution in reducing the amount of heat loss. This is also could be the reason why the average flux of hollow fiber AGMD module was only 22% lower, while the average thermal efficiency is 58% higher than that of hollow fiber DCMD module.
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| 21. |
- Axelsson, S., et al.
(författare)
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Theoretical and experimental investigations of three-terminal carbon nanotube nanorelays
- 2005
-
Ingår i: New J. Phys. - : IOP Publishing. - 1367-2630. ; 7
-
Tidskriftsartikel (refereegranskat)abstract
- We present theoretical and experimental investigations of three-terminal nanoelectromechanical relays based on suspended carbon nanotubes. A charge is induced in the nanotube by applying a voltage to an underlying gate electrode thus inducing the nanotube to bend and make contact with a drain electrode. Such devices have potential applications as fast switches, logic devices, memory elements and pulse generators. We describe two modes of operation: a contact mode where the nanotube makes physical contact with the drain electrode and a non-contact mode where electrical contact between the nanotube and the drain electrode is made via a field emission current.
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| 22. |
- Eriksson, Anders, 1975, et al.
(författare)
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Direct Transmission Detection of Tunable Mechanical Resonance in an Individual Carbon Nanofiber Relay
- 2008
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 8
-
Tidskriftsartikel (refereegranskat)abstract
- A direct on-chip transmission measurement of the resonance frequency of an individual singly clamped carbon nanofiber relay is reported. The experimental results are in good agreement with a small signal model and show the expected tuning of the resonance frequency with changing bias voltage.
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| 23. |
- Han, Sang Wook, et al.
(författare)
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An efficient spectrum sharing for throughput enhancement in heterogeneous networks
- 2014
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Ingår i: Proceedings of the International Symposium on Consumer Electronics, ISCE. - 9781479945924
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Konferensbidrag (refereegranskat)abstract
- Spectrum sharing has been considered as one of candidate technologies for enhancing spectral efficiency in wireless networks. Efficient cooperation among multiple radio access networks and proper system parameter setting regarding spectrum sharing are required in order to accomplish improvement on the system performance through spectrum sharing in such heterogeneous networks. This paper proposes a spectrum sharing scheme among access networks utilizing licensed and unlicensed band with an objective of enhancing system throughput while satisfying the user quality of service (QoS) under a simple condition of user deployment. A problem formulation to achieve the objective is suggested which enhances the system' spectral efficiency.
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| 24. |
- Lee, SangWook, et al.
(författare)
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A cross-contamination-free SELEX platform for a multi-target selection strategy
- 2013
-
Ingår i: Biochip Journal. - : Springer Science and Business Media LLC. - 2092-7843 .- 1976-0280. ; 7:1, s. 38-45
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Tidskriftsartikel (refereegranskat)abstract
- Multi-target aptamer selection, known as multiplex systematic evolution of ligands by exponential enrichment (SELEX), is rapidly drawing interest because of its potential to enable high-speed, high-throughput aptamer selection. The parallelization of chemical processes by integrating microfluidic unit operations is a key strategy for developing a multiplex SELEX process. One of the potential problems with on-chip multiplexing chemical processes is cross-contamination. In order to avoid this, we propose a microfluidic network platform that uses pneumatic valves to allow the serial loading and incubation of aptamers with sol-gel entrapped target proteins. After target binding inside the sol-gels, the cross-contamination-free parallel elution of specifically bound aptamers is performed. The platform allows selective binding with five different targets immobilized in sol-gel spots. When eluting bound species, cross-contamination is avoided by sealing the adjacent elution chambers from each other using the pneumatic microvalves. Consequently, we demonstrate specific aptamer binding to the respective protein target and subsequent aptamer elution without any cross-contamination. This proof of concept opens the way to increased automation and microscale parallel processing of the SELEX methodology.
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| 25. |
- Lee, Sangwook, et al.
(författare)
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A porous silicon immunoassay platform for fluorometric determination of alpha-synuclein in human cerebrospinal fluid
- 2014
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Ingår i: Microchimica Acta. - : Springer Science and Business Media LLC. - 1436-5073 .- 0026-3672. ; 181:9-10, s. 1143-1149
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Tidskriftsartikel (refereegranskat)abstract
- Levels of total and/or oligomeric alpha-synuclein may be used as a biomarker tool to aid in the diagnosis and development of new disease-modifying therapies. We report here on a porous silicon antibody microarray for the fluorimetric determination of cerebrospinal fluid levels of total alpha-synuclein, a protein involved the pathology of Parkinson's disease. The surface of porous silicon has a 3-dimensional macro- and nanoporous structure, and this offers a large binding capacity for capturing probe molecules. Porous silicon also warrants efficient immobilization of antibodies by surface adsorption, and does not require chemical immobilization. The platform requires 10 mu L of cerebrospinal fluid, and each test requires 4 h for assay only (including immobilization of capturing antibody). The limit of detection is 35 pg mL(-1) of alpha-synuclein in cerebrospinal fluid, and the dynamic analytical range extends from 0.01 to 100 ng center dot mL(-1).
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| 26. |
- Lee, SangWook, et al.
(författare)
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Improved porous silicon microarray based prostate specific antigen immunoassay by optimized surface density of the capture antibody
- 2013
-
Ingår i: Analytica Chimica Acta. - : Elsevier BV. - 1873-4324 .- 0003-2670. ; 796, s. 108-114
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Tidskriftsartikel (refereegranskat)abstract
- Enriching the surface density of immobilized capture antibodies enhances the detection signal of antibody sandwich microarrays. In this study, we improved the detection sensitivity of our previously developed P-Si (porous silicon) antibody microarray by optimizing concentrations of the capturing antibody. We investigated immunoassays using a P-Si microarray at three different capture antibody (PSA - prostate specific antigen) concentrations, analyzing the influence of the antibody density on the assay detection sensitivity. The LOD (limit of detection) for PSA was 2.5 ng mL(-1), 80 pg mL(1), and 800 fg mL(-1) when arraying the PSA antibody, H117 at the concentration 15 mu g mL(-1), 35 mu g mL(-1), and 154 mu g mL(-1), respectively. We further investigated PSA spiked into human female serum in the range of 800 fg mL(-1) to 500 ng mL(-1). The microarray showed a LOD of 800 fg mL(-1) and a dynamic range of 800 fg mL(-1) to 80 ng mL(-1) in serum spiked samples. (C) 2013 Elsevier B.V. All rights reserved.
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| 27. |
- Lee, SangWook, et al.
(författare)
-
In situ Raman measurements of suspended individual single-walled carbon nanotubes under strain
- 2007
-
Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 7, s. 2590-2595
-
Tidskriftsartikel (refereegranskat)abstract
- We present a technique for in situ Raman measurements of suspended individual single-walled carbon nanotubes (SWNTs) under strain. We observe a strong change in the radial breathing mode intensity with increasing strain as the nanotube moves out of (or into) resonance, and for strain greater than 2%, there is a clear irreversible upshift in the G-mode frequencies accompanied by an increase in intensity of a broad peak at a position associated with the D mode. For lower strain, the G-mode peaks (A1, E1, and E2) do not change significantly in position but change in relative intensity.
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| 28. |
- Mihnev, M. T., et al.
(författare)
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Microscopic origins of the terahertz carrier relaxation and cooling dynamics in graphene
- 2016
-
Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723 .- 2041-1723. ; 7
-
Tidskriftsartikel (refereegranskat)abstract
- The ultrafast dynamics of hot carriers in graphene are key to both understanding of fundamental carrier-carrier interactions and carrier-phonon relaxation processes in two-dimensional materials, and understanding of the physics underlying novel high-speed electronic and optoelectronic devices. Many recent experiments on hot carriers using terahertz spectroscopy and related techniques have interpreted the variety of observed signals within phenomenological frameworks, and sometimes invoke extrinsic effects such as disorder. Here, we present an integrated experimental and theoretical programme, using ultrafast timeresolved terahertz spectroscopy combined with microscopic modelling, to systematically investigate the hot-carrier dynamics in a wide array of graphene samples having varying amounts of disorder and with either high or low doping levels. The theory reproduces the observed dynamics quantitatively without the need to invoke any fitting parameters, phenomenological models or extrinsic effects such as disorder. We demonstrate that the dynamics are dominated by the combined effect of efficient carrier-carrier scattering, which maintains a thermalized carrier distribution, and carrier-optical-phonon scattering, which removes energy from the carrier liquid.
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| 29. |
- Morjan, Raluca Elena, 1976, et al.
(författare)
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Selective growth of individual multiwalled carbon nanotubes
- 2004
-
Ingår i: Current Applied Physics. - : Elsevier BV. - 1567-1739. ; 4:6, s. 591-594
-
Tidskriftsartikel (refereegranskat)abstract
- Growth of individual, vertically aligned multiwalled carbon nanotubes (VACNT) on patterned Si wafers using dc plasma-enhanced CVD is described. The selective growth of individual VACNT within larger holes etched in Si is demonstrated for the first time.
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| 30. |
- Sveningsson, Martin, 1977, et al.
(författare)
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Field emission from multiwalled carbon nanotubes – its application in NEMS
- 2005
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Ingår i: AIP COnference Proceedings. - 0094-243X .- 1551-7616. ; 786, s. 620-623
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Tidskriftsartikel (refereegranskat)abstract
- Nanoelectromechanical systems (NEMS) are a rapidly growing area of research. We discuss here the fabrication of two different three terminal nanorelay structures based on multi-walled carbon nanotubes (MWNT). Using a gate voltage the whole MWNT can be deflected and the tip of the carbon nanotube can be moved closer to a drain electrode making physical contact. In another device structure the carbon nanotubes are shorter so they never can get real physical contact with the drain electrode, instead this device is based on the process of electron field emission from the MWNT.
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| 31. |
- Svensson, Johannes, et al.
(författare)
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Carbon Nanotube Field Effect Transistors with Suspended Graphene Gates
- 2011
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 11:9, s. 3569-3575
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Tidskriftsartikel (refereegranskat)abstract
- Novel field effect transistors with suspended graphene gates are demonstrated. By incorporating mechanical motion of the gate electrode, it is possible to improve the switching characteristics compared to a static gate, as shown by a combination of experimental measurements and numerical simulations. The mechanical motion of the graphene gate is confirmed by using atomic force microscopy to directly measure the electrostatic deflection. The device geometry investigated here can also provide a sensitive measurement technique for detecting high-frequency motion of suspended membranes as required, e.g., for mass sensing.
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