Publications by authors named "Jin-Wook Lee"

100 Publications

Dynamic structural property of organic-inorganic metal halide perovskite.

iScience 2021 Jan 24;24(1):101959. Epub 2020 Dec 24.

Department of Energy Science and Nature Inspired Materials Processing Research Center, Sungkyunkwan University, Suwon 16419, Republic of Korea.

Unique organic-inorganic hybrid semiconducting materials have made a remarkable breakthrough in new class of photovoltaics (PVs). Organic-inorganic metal (Pb and/or Sn) halides (-I, -Br, and -Cl) are the semiconducting absorber with the crystal structure of the famous "Perovskite". It is widely called "perovskite solar cells (PSCs)" in PV society. Now, the power conversion efficiency (PCE) of PSCs is recorded in 25.5%. Prototypical composition of the absorbers is (A = methylammonium [MA], formamidinium [FA], and Cs), (M = Pb and/or Sn), and (X = I, Br, and Cl) in the form of perovskite AMX. Since the report on the stable all solid-state PSCs in 2012, the average annual growth rate of PCE is well over ∼10%. Such an outstanding PV performance attracts huge number of scientists in our research society. Their chemical as well as physical properties are dramatically different from monocrystalline Si, GaAs, other III-IV semiconductors, and many oxides with the crystal structure of perovskite. In this review, different fundamental aspects, in particular, the dynamic properties of A site cationic molecules and PbI octahedrons linked with their corners, from other semiconducting and dielectric materials are reviewed and summarized. Upon discussing unique properties, perspectives on the promising PV applications based on the comprehension in dynamic nature of the orientation in A site molecule and PbI octahedron tilting will be given.
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http://dx.doi.org/10.1016/j.isci.2020.101959DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7788097PMC
January 2021

Chronic Viral Hepatitis Is Associated with Colorectal Neoplasia: A Systematic Review and Meta-Analysis.

Dig Dis Sci 2021 Jan 12. Epub 2021 Jan 12.

Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Republic of Korea.

Background: Chronic viral hepatitis is associated with a wide range of extrahepatic diseases; however, evidence on a link between chronic viral hepatitis and colorectal neoplasia is still lacking.

Aims: To analyze the association between chronic viral hepatitis and prevalence of colorectal neoplasia.

Methods: A systematic review of articles published in the MEDLINE, EMBASE, and Cochrane Library between 2000 and 2020 was performed. Subgroup analyses based on the types of colorectal neoplasia and the etiology of chronic viral hepatitis were conducted.

Results: Twelve eligible studies with 48,428 hepatitis B virus (HBV) patients and 46,561 hepatitis C virus (HCV) patients were included. Chronic viral hepatitis was significantly associated with an increased risk of both colorectal adenoma (odds ratio [OR], 1.53; 95% confidence interval [CI], 1.16-2.02; I = 83%) and colorectal cancer (CRC) (OR, 1.32; 95% CI, 1.08-1.61; I = 94%). The etiology of chronic viral hepatitis was an independent factor related to heterogeneity for CRC subgroup analysis revealed an increased risk of CRC in both HBV (OR, 1.18; 95% CI, 1.09-1.27; I = 37%) and HCV (OR, 1.88; 95% CI, 1.78-1.97; I = 0%). HCV was associated with an increased risk of colorectal adenoma (OR, 1.48; 95% CI, 1.22-1.79; I = 0%); however, HBV was not associated with an increased risk of colorectal adenoma and had considerable heterogeneity (OR, 1.65; 95% CI, 0.88-3.09; I = 90%).

Conclusion: Our meta-analysis showed that chronic viral hepatitis is associated with an increased risk of colorectal neoplasia. The strategy of stricter screening colonoscopy may benefit from patients with chronic viral hepatitis.
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http://dx.doi.org/10.1007/s10620-020-06745-xDOI Listing
January 2021

Effects of Saturation Levels on the Ultrasonic Pulse Velocities and Mechanical Properties of Concrete.

Materials (Basel) 2020 Dec 31;14(1). Epub 2020 Dec 31.

Principal Researcher, Advanced Railroad Civil Engineering Division, Korea Railroad Research Institute, 176 Cheoldobangmulgwan-ro, Uiwang-si, Gyeonggi-do 16105, Korea.

The main objective of this research is to investigate the effect of water content in concrete on the velocities of ultrasonic waves (P- and S-waves) and mechanical properties (elastic modulus and compressive strength) of concrete. For this study, concrete specimens (100 mm × 200 mm cylinders) were fabricated with three different water-to-binder ratios (0.52, 0.35, and 0.26). These cylinders were then submerged in water to be saturated in different degrees from 25% to 100% with an interval of 25% saturation. Another set of cylinders was also oven-dried to represent the dry condition. The dynamic properties of concrete were then assessed using a measurement of elastic wave accordance with ASTM C597-16 and using resonance tests following ASTM C215-19, before and after immersion in water. The static properties of saturated concrete were also assessed by the uniaxial compressive testing according to ASTM C39/C39M-20 and ASTM C469/C469M-14. It was observed that the saturation level of concrete affected the two ultrasonic wave velocities and the two static mechanical properties of concrete in various ways. The relationship between P-wave velocity and compressive strength of concrete was highly sensitive to saturation condition of concrete. In contrast, S-wave velocity of concrete was closely correlated with compressive strength of concrete, which was much less sensitive to water saturation level compared to P-wave velocity of concrete. Finally, it was noticed that water saturation condition only little affects the relationship between the dynamic and elastic moduli of elasticity of concrete studies in this study.
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http://dx.doi.org/10.3390/ma14010152DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7795916PMC
December 2020

Electrical Resistivity Measurements of Reinforced Concrete Slabs with Delamination Defects.

Sensors (Basel) 2020 Dec 11;20(24). Epub 2020 Dec 11.

Department of ICT integrated Ocean Smart Cities Engineering, Dong-A University, Busan 225, Korea.

The main objectives of this research are to evaluate the effects of delamination defects on the measurement of electrical resistivity of reinforced concrete slabs through analytical and experimental studies in the laboratory, and to propose a practical guide for electrical resistivity measurements on concrete with delamination defects. First, a 3D finite element model was developed to simulate the variation of electric potential field in concrete over delamination defects with various depths and lateral sizes. Second, for experimental studies, two reinforced concrete slab specimens (1500 mm (width) by 1500 mm (length) by 300 mm (thickness)) with artificial delamination defects of various dimensions and depths were fabricated. Third, the electrical resistivity of concrete over delamination defects in the numerical simulation models and the two concrete slab specimens were evaluated by using a 4-point Wenner probe in accordance with AASHTO (American Association of State Highway and Transportation Office) T-358. It was demonstrated from analytical and experimental studies in this study that shallow (50 mm depth) and deep (250 mm depth) delamination defects resulted in higher and lower electrical resistivity (ER) values, respectively, as compared to measurements performed on solid concrete locations. Furthermore, the increase in size of shallow defects resulted in an increase in concrete resistivity, whereas the increase in sizes of deep delamination defects yielded opposite results. In addition, measurements done directly above the steel reinforcements significantly lowered ER values. Lastly, it was observed from experimental studies that the effect of delamination defects on the values of electrical resistivity decreases as the saturation level of concrete increases.
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http://dx.doi.org/10.3390/s20247113DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7764579PMC
December 2020

Molecular Interaction Regulates the Performance and Longevity of Defect Passivation for Metal Halide Perovskite Solar Cells.

J Am Chem Soc 2020 Nov 16;142(47):20071-20079. Epub 2020 Nov 16.

National Laboratory of Solid State Microstructures, College of Engineering and Applied Sciences, School of Physics, and Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210093, China.

Defect passivation constitutes one of the most commonly used strategies to fabricate highly efficient perovskite solar cells (PSCs). However, the durability of the passivation effects under harsh operational conditions has not been extensively studied regardless of the weak and vulnerable secondary bonding between the molecular passivation agents and perovskite crystals. Here, we incorporated strategically designed passivating agents to investigate the effect of their interaction energies on the perovskite crystals and correlated these with the performance and longevity of the passivation effects. We unraveled that the passivation agents with a stronger interaction energy are advantageous not only for effective defect passivation but also to suppress defect migration. The prototypical PSCs treated with the optimal passivation agent exhibited superior performance and operational stability, retaining 81.9 and 85.3% of their initial performance under continuous illumination or nitrogen at 85 °C after 1008 h, respectively, while the reference device completely degraded during that time. This work provides important insights into designing operationally durable defect passivation agents for perovskite optoelectronic devices.
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http://dx.doi.org/10.1021/jacs.0c09560DOI Listing
November 2020

Author Correction: Solid-phase hetero epitaxial growth of α-phase formamidinium perovskite.

Nat Commun 2020 Nov 12;11(1):5880. Epub 2020 Nov 12.

Department of Materials Science and Engineering, California NanoSystems Institute, University of California, Los Angeles, CA, 90095, USA.

A Correction to this paper has been published: https://doi.org/10.1038/s41467-020-19846-y .
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http://dx.doi.org/10.1038/s41467-020-19846-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7661531PMC
November 2020

Solid-phase hetero epitaxial growth of α-phase formamidinium perovskite.

Nat Commun 2020 Nov 2;11(1):5514. Epub 2020 Nov 2.

Department of Materials Science and Engineering, California NanoSystems Institute, University of California, Los Angeles, CA, 90095, USA.

Conventional epitaxy of semiconductor films requires a compatible single crystalline substrate and precisely controlled growth conditions, which limit the price competitiveness and versatility of the process. We demonstrate substrate-tolerant nano-heteroepitaxy (NHE) of high-quality formamidinium-lead-tri-iodide (FAPbI) perovskite films. The layered perovskite templates the solid-state phase conversion of FAPbI from its hexagonal non-perovskite phase to the cubic perovskite polymorph, where the growth kinetics are controlled by a synergistic effect between strain and entropy. The slow heteroepitaxial crystal growth enlarged the perovskite crystals by 10-fold with a reduced defect density and strong preferred orientation. This NHE is readily applicable to various substrates used for devices. The proof-of-concept solar cell and light-emitting diode devices based on the NHE-FAPbI showed efficiencies and stabilities superior to those of devices fabricated without NHE.
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http://dx.doi.org/10.1038/s41467-020-19237-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7608657PMC
November 2020

p16 Positivity of Melanocytes in Non-Segmental Vitiligo.

Diagnostics (Basel) 2020 Oct 28;10(11). Epub 2020 Oct 28.

Department of Medical Sciences, Ajou University Graduate School of Medicine, Suwon 443-721, Korea.

Cellular senescence is induced in response to cellular stressors such as increased levels of reactive oxygen species. The chronic accumulation of senescent cells is currently recognized as a contributor to the pathologic processes of diverse degenerative diseases. Vitiligo is characterized by the disappearance of melanocytes driven by cellular stress within melanocytes and autoimmune processes. In this study, we examined p16 positivity in the lesional and perilesional skin of 54 non-segmental vitiligo patients to explore cellular senescence in vitiligo. There were more p16-positive melanocytes in the perilesional vitiligo skin samples than in control samples. It was also found that p16 immunoreactivity was not restricted to melanocytes but also existed in fibroblasts; the number of p16-positive fibroblasts was significantly increased in lesional skin compared to perilesional skin and normal controls. However, in the subgroup analysis of sun-exposed and non-exposed samples, this outcome was only found at sun-exposed sites, suggesting that fibroblast senescence is an epiphenomenon related to the loss of pigment in skin with vitiligo. In summary, exploring p16 positivity in vitiligo revealed melanocyte senescence in perilesional skin, which may play a role in vitiligo pathogenesis.
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http://dx.doi.org/10.3390/diagnostics10110878DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7694005PMC
October 2020

High-Efficiency Perovskite Solar Cells.

Chem Rev 2020 Aug 28;120(15):7867-7918. Epub 2020 Jul 28.

School of Chemical Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea.

With rapid progress in a power conversion efficiency (PCE) to reach 25%, metal halide perovskite-based solar cells became a game-changer in a photovoltaic performance race. Triggered by the development of the solid-state perovskite solar cell in 2012, intense follow-up research works on structure design, materials chemistry, process engineering, and device physics have contributed to the revolutionary evolution of the solid-state perovskite solar cell to be a strong candidate for a next-generation solar energy harvester. The high efficiency in combination with the low cost of materials and processes are the selling points of this cell over commercial silicon or other organic and inorganic solar cells. The characteristic features of perovskite materials may enable further advancement of the PCE beyond those afforded by the silicon solar cells, toward the Shockley-Queisser limit. This review summarizes the fundamentals behind the optoelectronic properties of perovskite materials, as well as the important approaches to fabricating high-efficiency perovskite solar cells. Furthermore, possible next-generation strategies for enhancing the PCE over the Shockley-Queisser limit are discussed.
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http://dx.doi.org/10.1021/acs.chemrev.0c00107DOI Listing
August 2020

Activation of JUN in fibroblasts promotes pro-fibrotic programme and modulates protective immunity.

Nat Commun 2020 06 3;11(1):2795. Epub 2020 Jun 3.

Department of Pathology, Institute of Stem Cell Biology and Regenerative Medicine (ISCBRM), Stanford University School of Medicine, Stanford, 94305, CA, USA.

The transcription factor JUN is highly expressed in pulmonary fibrosis. Its induction in mice drives lung fibrosis, which is abrogated by administration of anti-CD47. Here, we use high-dimensional mass cytometry to profile protein expression and secretome of cells from patients with pulmonary fibrosis. We show that JUN is activated in fibrotic fibroblasts that expressed increased CD47 and PD-L1. Using ATAC-seq and ChIP-seq, we found that activation of JUN rendered promoters and enhancers of CD47 and PD-L1 accessible. We further detect increased IL-6 that amplified JUN-mediated CD47 enhancer activity and protein expression. Using an in vivo mouse model of fibrosis, we found two distinct mechanisms by which blocking IL-6, CD47 and PD-L1 reversed fibrosis, by increasing phagocytosis of profibrotic fibroblasts and by eliminating suppressive effects on adaptive immunity. Our results identify specific immune mechanisms that promote fibrosis and suggest a therapeutic approach that could be used alongside conventional anti-fibrotics for pulmonary fibrosis.
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http://dx.doi.org/10.1038/s41467-020-16466-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7270081PMC
June 2020

Hybrid Integrated Photomedical Devices for Wearable Vital Sign Tracking.

ACS Sens 2020 06 13;5(6):1582-1588. Epub 2020 Apr 13.

Department of Materials Science and Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States.

In light of the importance of and challenges inherent in realizing a wearable healthcare platform for simultaneously recognizing, preventing, and treating diseases while tracking vital signs, the development of simple and customized functional devices has been required. Here, we suggest a new approach for making a stretchable light waveguide which can be combined with integrated functional devices, such as organic photodetectors (PDs) and nanowire-based heaters, for multifunctional healthcare monitoring. Controlling the reflection condition of the medium gave a solid design rule for strong light emission in our stretchable waveguides. Based on this rule, the stretchable light waveguide (up to 50% strain) made of polydimethylsiloxane was successfully demonstrated with strong emissions. We also incorporated highly sensitive organic PDs and silver nanowire-based heaters with the stretchable waveguide for the detection of vital signs, including the heart rate, deep breathing, coughs, and blood oxygen saturation. Through these multifunctional performances, we have successfully demonstrated that our stretchable light waveguide has a strong potential for multifunctional healthcare monitoring.
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http://dx.doi.org/10.1021/acssensors.9b02529DOI Listing
June 2020

A Polymerization-Assisted Grain Growth Strategy for Efficient and Stable Perovskite Solar Cells.

Adv Mater 2020 Apr 8;32(17):e1907769. Epub 2020 Mar 8.

Department of Materials Science and Engineering and California Nano Systems Institute, University of California, Los Angeles, CA, 90095, USA.

Intrinsically, detrimental defects accumulating at the surface and grain boundaries limit both the performance and stability of perovskite solar cells. Small molecules and bulkier polymers with functional groups are utilized to passivate these ionic defects but usually suffer from volatility and precipitation issues, respectively. Here, starting from the addition of small monomers in the PbI precursor, a polymerization-assisted grain growth strategy is introduced in the sequential deposition method. With a polymerization process triggered during the PbI film annealing, the bulkier polymers formed will be adhered to the grain boundaries, retaining the previously established interactions with PbI . After perovskite formation, the polymers anchored on the boundaries can effectively passivate undercoordinated lead ions and reduce the defect density. As a result, a champion power conversion efficiency (PCE) of 23.0% is obtained, together with a prolonged lifetime where 85.7% and 91.8% of the initial PCE remain after 504 h continuous illumination and 2208 h shelf storage, respectively.
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http://dx.doi.org/10.1002/adma.201907769DOI Listing
April 2020

Detrimental Effect of Unreacted PbI on the Long-Term Stability of Perovskite Solar Cells.

Adv Mater 2020 Apr 27;32(16):e1905035. Epub 2020 Feb 27.

Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan.

Excess/unreacted lead iodide (PbI ) has been commonly used in perovskite films for the state-of-the-art solar cell applications. However, an understanding of intrinsic degradation mechanisms of perovskite solar cells (PSCs) containing unreacted PbI has been still insufficient and, therefore, needs to be clarified for better operational durability. Here, it is shown that degradation of PSCs is hastened by unreacted PbI crystals under continuous light illumination. Unreacted PbI undergoes photodecomposition under illumination, resulting in the formation of lead and iodine in films. Thus, this photodecomposition of PbI is one of the main reasons for accelerated device degradation. Therefore, this work reveals that carefully controlling the formation of unreacted PbI crystals in perovskite films is very important to improve device operational stability for diverse opto-electronic applications in the future.
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http://dx.doi.org/10.1002/adma.201905035DOI Listing
April 2020

Steric Impediment of Ion Migration Contributes to Improved Operational Stability of Perovskite Solar Cells.

Adv Mater 2020 Mar 4;32(11):e1906995. Epub 2020 Feb 4.

Department of Materials Science and Engineering and California NanoSystems Institute, University of California Los Angeles, Los Angeles, CA, 90095, USA.

The operational instability of perovskite solar cells (PSCs) is known to mainly originate from the migration of ionic species (or charged defects) under a potential gradient. Compositional engineering of the "A" site cation of the ABX perovskite structure has been shown to be an effective route to improve the stability of PSCs. Here, the effect of size-mismatch-induced lattice distortions on the ion migration energetics and operational stability of PSCs is investigated. It is observed that the size mismatch of the mixed "A" site composition films and devices leads to a steric effect to impede the migration pathways of ions to increase the activation energy of ion migration, which is demonstrated through multiple theoretical and experimental evidence. Consequently, the mixed composition devices exhibit significantly improved thermal stability under continuous heating at 85 °C and operational stability under continuous 1 sun illumination, with an extrapolated lifetime of 2011 h, compared to the 222 h of the reference device.
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http://dx.doi.org/10.1002/adma.201906995DOI Listing
March 2020

Evaluation of Delamination in Concrete by IE Testing Using Multi-Channel Elastic Wave Data.

Sensors (Basel) 2019 Dec 30;20(1). Epub 2019 Dec 30.

Department of Architectural Engineering, Dong-A University, 37 Nakdong-Daero 550 Beon-gil Saha-gu, Busan 69315, Korea.

The main objectives of this study are to develop a non-destructive test method for evaluating delamination defects in concrete by the Impact-echo test using multi-channel elastic wave data and to verify the validity of the proposed method by experimental studies in the laboratory. First, prototype equipment using an eight-channel linear sensor array was developed to perform elastic wave measurements on the surface of the concrete. In this study, three concrete slab specimens (1500 mm (width) by 1500 mm (length) by 300 mm (thickness)), with simulated delamination defects of various lateral dimensions and depth, were designed and constructed in the laboratory. Multi-channel elastic wave signals measured on the three concrete specimens were converted to the frequency-phase velocity image by using the phase-shift method. A data processing method was proposed to extract the dominant propagating waves and non-propagating waves from the dispersion images. The dominant wave modes were used to evaluate delamination defects in concrete. It was demonstrated that the surface wave velocity values were useful for characterizing the shallow delamination defects in concrete. In addition, the peak frequency of non-propagating wave modes extracted from the dispersion images gives information on the lateral dimensions and depths of the delamination defects. This study also discussed the feasibility of combined use of the results from propagating and non-propagating wave modes to better understand the information on delamination defects in concrete. As will be discussed, the multi-channel elastic wave measurements enable more accurate, consistent, and rapid measurements and data processing for evaluation of delamination defects in concrete than the single-channel sensing method.
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http://dx.doi.org/10.3390/s20010201DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6983097PMC
December 2019

Risk factors associated with hypophosphatemia in chronic Hepatitis B patients treated with tenofovir disoproxil fumarate.

Medicine (Baltimore) 2019 Dec;98(50):e18351

Department of Internal Medicine, Kosin University College of Medicine, Busan, Korea.

Tenofovir disoproxil fumarate (TDF) is thought to cause varying degrees of hypophosphatemia in patients with chronic hepatitis B (CHB). Therefore, we investigated factors that cause hypophosphatemia in patients treated with TDF and methods to increase serum phosphorus concentrations in clinical practice.We completed a retrospective review of patients with CHB treated with TDF initially at Kosin University Gospel Hospital, Busan, Korea from January 2012 to January 2017. Subclinical hypophosphatemia and hypophosphatemia were defined as serum phosphorus below 3.0 mg/dL and 2.5 mg/dL, respectively.We screened 206 patients with CHB treated with TDF, among which 135 were excluded for the following reasons: baseline malignancy (59), limited data (50), co-administered other antivirals (14), hypophosphatemia at baseline (7), and other reasons (5). The final study population comprised 71 patients. Subclinical hypophosphatemia developed in 43 (60.5%) patients. Hypophosphatemia occurred in 18 patients (25.3%). Liver cirrhosis was the most significant predictor of hypophosphatemia (P = .038, OR = 3.440, CI = 1.082-10.937) Patients diagnosed with subclinical hypophosphatemia were encouraged to increase their intake of nuts and dairy products (25 patients) or reduce their alcohol intake (2), dose reduction of TDF (4) or placed under observation (4). Among patients with subclinical hypophosphatemia, serum phosphorus concentrations were elevated (>3.0 mg/dL) in 23 of 36 patients (63.8%). Increased nut and dairy intake increased phosphorus concentrations to more than 3.0 mg/dl in 16 of 25 patients (64.0%).Entecavir or tenofovir alafenamide fumarate (TAF) should be considered rather than TDF in patients with liver cirrhosis because of the risk of hypophosphatemia. Instead of stopping TDF treatment, encouraging increased intake of phosphorus-rich foods could increase serum phosphorus concentrations in clinical practice.
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http://dx.doi.org/10.1097/MD.0000000000018351DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6922420PMC
December 2019

The ENCODE Portal as an Epigenomics Resource.

Curr Protoc Bioinformatics 2019 12;68(1):e89

Department of Genetics, Stanford University, Stanford, California.

The Encyclopedia of DNA Elements (ENCODE) web portal hosts genomic data generated by the ENCODE Consortium, Genomics of Gene Regulation, The NIH Roadmap Epigenomics Consortium, and the modENCODE and modERN projects. The goal of the ENCODE project is to build a comprehensive map of the functional elements of the human and mouse genomes. Currently, the portal database stores over 500 TB of raw and processed data from over 15,000 experiments spanning assays that measure gene expression, DNA accessibility, DNA and RNA binding, DNA methylation, and 3D chromatin structure across numerous cell lines, tissue types, and differentiation states with selected genetic and molecular perturbations. The ENCODE portal provides unrestricted access to the aforementioned data and relevant metadata as a service to the scientific community. The metadata model captures the details of the experiments, raw and processed data files, and processing pipelines in human and machine-readable form and enables the user to search for specific data either using a web browser or programmatically via REST API. Furthermore, ENCODE data can be freely visualized or downloaded for additional analyses. © 2019 The Authors. Basic Protocol: Query the portal Support Protocol 1: Batch downloading Support Protocol 2: Using the cart to download files Support Protocol 3: Visualize data Alternate Protocol: Query building and programmatic access.
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http://dx.doi.org/10.1002/cpbi.89DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7307447PMC
December 2019

Surface-2D/Bulk-3D Heterophased Perovskite Nanograins for Long-Term-Stable Light-Emitting Diodes.

Adv Mater 2020 Jan 18;32(1):e1905674. Epub 2019 Nov 18.

Department of Materials Science and Engineering and California NanoSystems Institute, University of California, Los Angeles, CA, 90095, USA.

Although metal halide perovskite (MHP) light-emitting diodes (LEDs) have demonstrated great potential in terms of electroluminescence efficiency, the operational stability of MHP LEDs currently remains the biggest bottleneck toward their practical usage. Well-confined excitons/charge carriers in a dielectric/quantum well based on conventional spatial or potential confinement approaches substantially enhance radiative recombination in MHPs, but an increased surface-to-volume ratio and multiphase interfaces likely result in a high degree of surface or interface defect states, which brings about a critical environmentally/operationally vulnerable point on LED stability. Here, an effective solution is suggested to mitigate such drawbacks using strategically designed surface-2D/bulk-3D heterophased MHP nanograins for long-term-stable LEDs. The 2D surface-functionalized MHP renders significantly reduced trap density, environmental stability, and an ion-migration-immune surface in addition to a fast radiative recombination owing to its spatially and potentially confined charge carriers, simultaneously. As a result, heterophased MHP LEDs show substantial improvement in operational lifetime (T : >200 h) compared to conventional pure 3D or quasi-2D counterparts (T : < 0.2 h) as well as electroluminescence efficiency (surface-2D/bulk-3D: ≈7.70 ph per el% and pure 3D: ≈0.46 ph per el%).
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http://dx.doi.org/10.1002/adma.201905674DOI Listing
January 2020

New developments on the Encyclopedia of DNA Elements (ENCODE) data portal.

Nucleic Acids Res 2020 01;48(D1):D882-D889

Department of Genetics, Stanford University, Stanford, CA 94305-5477, USA.

The Encyclopedia of DNA Elements (ENCODE) is an ongoing collaborative research project aimed at identifying all the functional elements in the human and mouse genomes. Data generated by the ENCODE consortium are freely accessible at the ENCODE portal (https://www.encodeproject.org/), which is developed and maintained by the ENCODE Data Coordinating Center (DCC). Since the initial portal release in 2013, the ENCODE DCC has updated the portal to make ENCODE data more findable, accessible, interoperable and reusable. Here, we report on recent updates, including new ENCODE data and assays, ENCODE uniform data processing pipelines, new visualization tools, a dataset cart feature, unrestricted public access to ENCODE data on the cloud (Amazon Web Services open data registry, https://registry.opendata.aws/encode-project/) and more comprehensive tutorials and documentation.
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http://dx.doi.org/10.1093/nar/gkz1062DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7061942PMC
January 2020

Effectiveness, safety, and economic evaluation of adjuvant moxibustion therapy for aromatase inhibitor-induced arthralgia of postmenopausal breast cancer stage I to III patients: Study protocol for a prospective, randomized, assessor-blind, usual-care controlled, parallel-group, pilot clinical trial.

Medicine (Baltimore) 2019 Sep;98(38):e17260

Department of Korean Obstetrics & Gynecology, College of Korean Medicine, Kyung Hee University, Seoul, Republic of Korea.

Introduction: This study is a prospective, assessor-blinded, parallel-group, randomized controlled pilot trial to explore the effectiveness of 12-week adjuvant moxibustion therapy for arthralgia in menopausal females at stage I to III breast cancer on aromatase inhibitor (AI) administration, compared with those receiving usual care.

Methods/design: Forty-six menopausal female patients with breast cancer who completed cancer therapy will be randomly allocated to either adjuvant moxibustion or usual care groups with a 1:1 allocation ratio. The intervention group will undergo 24 sessions of adjuvant moxibustion therapy with usual care for 12 weeks, whereas the control group will receive only usual care during the same period. The usual care consists of acetaminophen administration on demand and self-directed exercise education to manage AI-related joint pain. The primary outcome is the mean change of the worst pain level according to the Brief Pain Inventory-Short Form between the initial visit and the endpoint. The mean changes in depression, fatigue, and quality of life will also be compared between groups. Safety and pharmacoeconomic evaluations will also be included.

Discussion: Continuous variables will be compared by an independent t test or Wilcoxon rank-sum test between the adjuvant moxibustion and usual care groups. Adverse events will be analyzed using the chi-square or Fisher exact test. The statistical analysis will be performed by a 2-tailed test at a significance level of .05.
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http://dx.doi.org/10.1097/MD.0000000000017260DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6756724PMC
September 2019

Controlled Redox of Lithium-Ion Endohedral Fullerene for Efficient and Stable Metal Electrode-Free Perovskite Solar Cells.

J Am Chem Soc 2019 Oct 30;141(42):16553-16558. Epub 2019 Sep 30.

Department of Mechanical Engineering , The University of Tokyo , 7-3-1 Hongo , Bunkyo-ku, Tokyo 113-8656 , Japan.

High efficiency perovskite solar cells have underpinned the rapid growth of the field. However, their low device stability limits further advancement. Hygroscopic lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and metal electrode are the main causes of the device instability. In this work, the redox reaction between lithium-ion endohedral fullerenes and 2,2',7,7'-tetrakis(,-di--methoxyphenylamine)-9,9'-spirobi-fluorene (spiro-MeOTAD) was controlled to optimize the amount of oxidized spiro-MeOTAD and antioxidizing neutral endohedral fullerenes. Application of this mixture to metal-free carbon nanotube (CNT)-laminated perovskite solar cells resulted in 17.2% efficiency with a stability time of more than 1100 h under severe conditions (temperature = 60 °C, humidity = 70%). Such high performance is attributed to the uninhibited charge flow, no metal-ion migration, and the enhanced antioxidizing activity of the devices.
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http://dx.doi.org/10.1021/jacs.9b06418DOI Listing
October 2019

A Practical Guide to Source and Receiver Locations for Surface Wave Transmission Measurements across a Surface-Breaking Crack in Plate Structures.

Sensors (Basel) 2019 Sep 1;19(17). Epub 2019 Sep 1.

Department of Architectural Engineering, Dong-A University, 37, Nakdong-Daero 550 Beon-gil Saha-gu, Busan 69315, Korea.

The main objectives of this study are to investigate the interference of multiple bottom reflected waves in the surface wave transmission (SWT) measurements in a plate and to propose a practical guide to source-and-receiver locations to obtain reliable and consistent SWT measurements in a plate. For these purposes, a series of numerical simulations, such as finite element modelling (FEM), are performed to investigate the variation of transmission coefficient of surface waves across a surface-breaking crack in various source-to-receiver configurations in plates. Main variables in this study include the crack depths (0, 10, 20, 30, 40 and 50 mm), plate thicknesses (150, 200, 300, 400 and 800 mm), source-to-crack distances (100, 150, 200, 250 and 300 mm) and receiver-to-crack distances. The validity of numerical simulation results was verified by comparison with results from experiments using Plexiglas specimens using two types of noncontact sensors (laser vibrometer and air-coupled sensor) in the laboratory. Based on simulation and experimental results in this study, practical guidelines for sensor-to-receiver locations are proposed to reduce the effects of the interference of bottom reflected waves on the SWT measurements across a surface-breaking crack in a plate. The findings in this study will help obtain reliable and consistent SWT measurements across a surface-breaking crack in plate-like structures.
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http://dx.doi.org/10.3390/s19173793DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6749318PMC
September 2019

Crystalline Liquid-like Behavior: Surface-Induced Secondary Grain Growth of Photovoltaic Perovskite Thin Film.

J Am Chem Soc 2019 Sep 21;141(35):13948-13953. Epub 2019 Aug 21.

Department of Materials Science and Engineering and California NanoSystems Institute , University of California Los Angeles , California 90095 , United States.

Surface effects usually become negligible on the micrometer or sub-micrometer scale due to lower surface-to-bulk ratio compared to nanomaterials. In lead halide perovskites, however, their "soft" nature renders them highly responsive to the external field, allowing for extended depth scale affected by the surface. Herein, by taking advantage of this unique feature of perovskites we demonstrate a methodology for property manipulation of perovskite thin films based on secondary grain growth, where tuning of the surface induces the internal property evolution of the entire perovskite film. While in conventional microelectronic techniques secondary grain growth generally involves harsh conditions such as high temperature and straining, it is easily triggered in a perovskite thin film by a simple surface post-treatment, producing enlarged grain sizes of up to 4 μm. The resulting photovoltaic devices exhibit significantly enhanced power conversion efficiency and operational stability over a course of 1000 h and an ambient shelf stability of over 4000 h while maintaining over 90% of its original efficiency.
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http://dx.doi.org/10.1021/jacs.9b06940DOI Listing
September 2019

A Small-Molecule "Charge Driver" enables Perovskite Quantum Dot Solar Cells with Efficiency Approaching 13.

Adv Mater 2019 Sep 25;31(37):e1900111. Epub 2019 Jul 25.

Department of Materials Science and Engineering and California NanoSystems Institute, University of California, Los Angeles, CA, 90095, USA.

Halide perovskite colloidal quantum dots (CQDs) have recently emerged as a promising candidate for CQD photovoltaics due to their superior optoelectronic properties to conventional chalcogenides CQDs. However, the low charge separation efficiency due to quantum confinement still remains a critical obstacle toward higher-performance perovskite CQD photovoltaics. Available strategies employed in the conventional CQD devices to enhance the carrier separation, such as the design of type-Ⅱ core-shell structure and versatile surface modification to tune the electronic properties, are still not applicable to the perovskite CQD system owing to the difficulty in modulating surface ligands and structural integrity. Herein, a facile strategy that takes advantage of conjugated small molecules that provide an additional driving force for effective charge separation in perovskite CQD solar cells is developed. The resulting perovskite CQD solar cell shows a power conversion efficiency approaching 13% with an open-circuit voltage of 1.10 V, short-circuit current density of 15.4 mA cm , and fill factor of 74.8%, demonstrating the strong potential of this strategy toward achieving high-performance perovskite CQD solar cells.
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http://dx.doi.org/10.1002/adma.201900111DOI Listing
September 2019

Gardenia jasminoides extract without crocin improved atopic dermatitis-like skin lesions via suppression of Th2-related cytokines in Dfe-induced NC/Nga mice.

J Ethnopharmacol 2019 Sep 4;241:112015. Epub 2019 Jun 4.

Herbal Medicine Research, Korea Institute of Oriental Medicine (KIOM), 1672 Yuseong-daero, Yuseong-gu, Daejeon, 305-811, Republic of Korea. Electronic address:

Ethnopharmacological Relevance: Atopic dermatitis (AD) is a pruritic, chronic, relapsing inflammatory skin disease. Gardenia jasminoides extract (GJE) has been used as a traditional remedy for the treatment of various inflammatory diseases, including AD. The specific effects of the extract components, which include crocin, geniposidic acid, and gardenoside, on inflammatory responses in AD are not entirely clear.

Aim Of The Study: We determined the effects of G. jasminoides extract with crocin removed (GJE-C) on AD-like skin lesions in Dermatophagoies farina crude extract (Dfe)-treated NC/Nga mice, a well-known AD mouse model.

Materials And Methods: To prepare the mice, 150 μl of 4% sodium dodecyl sulfate (SDS) was applied to the shaved dorsal skin or ear of NC/Nga mice 1 h before application of 100 mg Dfe. After 7 d, GJE-C was applied every day for 14 d. We performed behavior, histological, ELISA, assays to evaluate chemokines, cytokines, and skin barrier proteins in skin or serum samples from treated and untreated NC/Nga mice.

Results: Topical application of GJE-C improved the severity scores of the AD-like skin lesions, frequency of scratching, and ear swelling in Dfe-treated NC/Nga mice similar to the complete GJE. In addition, GJE-C also reduced serum IgE and chemokine levels as well as the inflammatory response. Topical application of GJE-C also resulted in decreased infiltration of inflammatory cells, such as mast cells, via reduction of Th2 inflammatory mediators, including interleukin (IL)-4, IL-5, and IL-13, pro-inflammatory cytokines, and chemokines, and increased skin barrier protein expression in Dfe-treated NC/Nga mice. The GJE components geniposidic acid and gardenoside inhibited the production of atopic-related chemokines in HaCaT cells, but inclusion of crocin dampened this inhibition of chemokine production.

Conclusions: Together, these findings indicate that GJE-C may improve AD-like lesions by inhibiting the Th2 inflammatory response and expression of chemokines while increasing the expression of skin barrier proteins. These data provide experimental evidence that GJE-C may harbor therapeutic potential for AD.
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http://dx.doi.org/10.1016/j.jep.2019.112015DOI Listing
September 2019

Effectiveness, safety, and economic evaluation of topical application of a herbal ointment, Jaungo, for radiation dermatitis after breast conserving surgery in patients with breast cancer (GREEN study): Study protocol for a randomized controlled trial.

Medicine (Baltimore) 2019 Apr;98(15):e15174

Associate Professor, Department of Korean Obstetrics and Gynecology, College of Korean Medicine, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul, Republic of Korea.

Introduction: This is a prospective, open-label, parallel-group, randomized controlled trial that evaluates the effectiveness and safety of adjuvant application of Jaungo (JUG) for radiation-induced dermatitis (RD) in breast cancer patients undergoing radiation therapy, in comparison with general supportive care (GSC).

Methods/design: Eighty female patients, who have been diagnosed with unilateral breast cancer, will be allocated to either the JUG or GSC group with an allocation ratio of 1:1 after breast conservation surgery, in the Kyung Hee University Korean Medicine Hospital, Seoul, Republic of Korea. Both the groups will be subjected to GSC, but only the JUG group participants will apply adjuvant JUG ointment on the irradiated skin for 6 weeks, twice a day. The primary outcome of this study is the assessment of incidence rate of RD using the Radiation Therapy Oncology Group (RTOG) for toxicity gradation of 2 or more. Maximum pain level, quality of life, adverse reactions, and pharmacoeconomic evaluations will also be included.

Discussion: The primary outcome will be statistically compared using the logrank test after estimating the survival curve using the Kaplan-Meier method. Continuous variables will be tested using independent t test or Mann-Whitney U test. The adverse events will be evaluated with Chi-square or Fisher exact test. All the data will be analyzed at a significance level of 0.05 (two-sided) with R software (The R Foundation).

Trial Registration: CRIS (Clinical Research Information Service), KCT0003506, 14 February 2019.
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http://dx.doi.org/10.1097/MD.0000000000015174DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6485874PMC
April 2019

Interface and Defect Engineering for Metal Halide Perovskite Optoelectronic Devices.

Adv Mater 2019 Nov 14;31(47):e1803515. Epub 2019 Feb 14.

Department of Materials Science and Engineering and California NanoSystems Institute, University of California, Los Angeles, CA, 90095, USA.

Metal halide perovskites have been in the limelight in recent years due to their enormous potential for use in optoelectronic devices, owing to their unique combination of properties, such as high absorption coefficient, long charge-carrier diffusion lengths, and high defect tolerance. Perovskite-based solar cells and light-emitting diodes (LEDs) have achieved remarkable breakthroughs in a comparatively short amount of time. As of writing, a certified power conversion efficiency of 22.7% and an external quantum efficiency of over 10% have been achieved for perovskite solar cells and LEDs, respectively. Interfaces and defects have a critical influence on the properties and operational stability of metal halide perovskite optoelectronic devices. Therefore, interface and defect engineering are crucial to control the behavior of the charge carriers and to grow high quality, defect-free perovskite crystals. Herein, a comprehensive review of various strategies that attempt to modify the interfacial characteristics, control the crystal growth, and understand the defect physics in metal halide perovskites, for both solar cell and LED applications, is presented. Lastly, based on the latest advances and breakthroughs, perspectives and possible directions forward in a bid to transcend what has already been achieved in this vast field of metal halide perovskite optoelectronic devices are discussed.
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http://dx.doi.org/10.1002/adma.201803515DOI Listing
November 2019

Perovskite-polymer composite cross-linker approach for highly-stable and efficient perovskite solar cells.

Nat Commun 2019 01 31;10(1):520. Epub 2019 Jan 31.

Department of Materials Science and Engineering, and California NanoSystems Institute, University of California, Los Angeles, CA, 90095, USA.

Manipulation of grain boundaries in polycrystalline perovskite is an essential consideration for both the optoelectronic properties and environmental stability of solar cells as the solution-processing of perovskite films inevitably introduces many defects at grain boundaries. Though small molecule-based additives have proven to be effective defect passivating agents, their high volatility and diffusivity cannot render perovskite films robust enough against harsh environments. Here we suggest design rules for effective molecules by considering their molecular structure. From these, we introduce a strategy to form macromolecular intermediate phases using long chain polymers, which leads to the formation of a polymer-perovskite composite cross-linker. The cross-linker functions to bridge the perovskite grains, minimizing grain-to-grain electrical decoupling and yielding excellent environmental stability against moisture, light, and heat, which has not been attainable with small molecule defect passivating agents. Consequently, all photovoltaic parameters are significantly enhanced in the solar cells and the devices also show excellent stability.
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http://dx.doi.org/10.1038/s41467-019-08455-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6355927PMC
January 2019

Vapor-Assisted Ex-Situ Doping of Carbon Nanotube toward Efficient and Stable Perovskite Solar Cells.

Nano Lett 2019 04 11;19(4):2223-2230. Epub 2018 Dec 11.

Department of Materials Science and Engineering and California Nano Systems Institute , University of California , Los Angeles , California 90095 , United States.

Single-walled carbon nanotubes (CNTs) has been considered as a promising material for a top electrode of perovskite solar cells owing to its hydrophobic nature, earth-abundance, and mechanical robustness. However, its poor conductivity, a shallow work function, and nonreflective nature have limited further enhancement in power conversion efficiency (PCE) of top CNT electrode-based perovskite solar cells. Here, we introduced a simple and scalable method to address these issues by utilizing an ex-situ vapor-assisted doping method. Trifluoromethanesulfonic acid (TFMS) vapor doping of the free-standing CNT sheet enabled tuning of conductivity and work function of the CNT electrode without damaging underneath layers. The sheet resistance of the CNT sheet was decreased by 21.3% with an increase in work function from 4.75 to 4.96 eV upon doping of TFMS. In addition, recently developed 2D perovskite-protected Cs-containing formamidium lead iodide (FACsPbI) technology was employed to maximize the absorption. Because of the lowered resistance, better energy alignment, and improved absorption, the CNT electrode-based PSCs produced a PCE of 17.6% with a J of 24.21 mA/cm, V of 1.005 V, and FF of 0.72. Furthermore, the resulting TFMS-doped CNT-PSCs demonstrated higher thermal and operational stability than bare CNT and metal electrode-based devices.
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http://dx.doi.org/10.1021/acs.nanolett.8b04190DOI Listing
April 2019

Tailored Phase Conversion under Conjugated Polymer Enables Thermally Stable Perovskite Solar Cells with Efficiency Exceeding 21.

J Am Chem Soc 2018 Dec 30;140(49):17255-17262. Epub 2018 Nov 30.

Department of Materials Science and Engineering , University of California , Los Angeles , California 90095 , United States.

The precise control of stoichiometric balance and ionic defects on the surface of solution-processed perovskite is critical to the performance and stability of perovskite solar cells (pero-SCs). Here, we introduce a low-cost and stable conjugated donor polymer (PTQ10) as interfacial layer in the planar n-i-p structured pero-SCs. The polymer was applied to the perovskite intermediate phase before the thermal annealing. This treatment significantly reduced the loss of surface organic cation during thermal annealing. Importantly, the kinetics of phase conversion of perovskite was influenced, and perovskite crystal showed a more preferential orientation. Moreover, the polymer proved to be an effective hole extraction layer due to the proper energy alignment with perovskite. Finally, a champion power conversion efficiency of the planar pero-SCs was achieved at 21.2% with a high fill factor of 81.6%. The devices also showed great ambient and thermal stability. This work presents a facile way of perovskite surface control to achieve high-performance pero-SCs.
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http://dx.doi.org/10.1021/jacs.8b10520DOI Listing
December 2018