The synthesis of atomically thin transition-metal disulfides (MS2) with layer controllability and large-area uniformity is an essential requirement for their application in electronic and optical ...devices. In this work, we describe a process for the synthesis of WS2 nanosheets through the sulfurization of an atomic layer deposition (ALD) WO3 film with systematic layer controllability and wafer-level uniformity. The X-ray photoemission spectroscopy, Raman, and photoluminescence measurements exhibit that the ALD-based WS2 nanosheets have good stoichiometry, clear Raman shift, and bandgap dependence as a function of the number of layers. The electron mobility of the monolayer WS2 measured using a field-effect transistor (FET) with a high-k dielectric gate insulator is shown to be better than that of CVD-grown WS2, and the subthreshold swing is comparable to that of an exfoliated MoS2 FET device. Moreover, by utilizing the high conformality of the ALD process, we have developed a process for the fabrication of WS2 nanotubes.
The wind data measured from automated weather stations (AWS) at complex terrain in Korea was used to predict the wind speed at nearby sites that are several kilometers away. The 10-minute averaged ...wind data was measured at a height of 10 meters. A commercial CFD code, WindSIM, based on the Reynolds averaged Navier-Stokes equation was employed. The results were compared with the data measured using meteorological masts (MM) at heights of 30 to 50 meters installed for this study. The predictions using the AWS data and WindSIM showed good agreements with the measured data. The results are expected to be useful to find out a spot to install a meteorological mast for future wind farm development in complex terrain.
Photodiodes made from core–shell nanowires (NWs) comprising n-type silicon (n-Si; core) and nitrogen-doped ZnO (ZnO:N; shell) were fabricated by atomic layer deposition of ZnO:N on vertically aligned ...Si NWs. The device properties were investigated as functions of nitrogen content of the ZnO:N shell. The electron-carrier concentration of ZnO:N was modulated by adjusting the concentration of the reactant, diluted ammonium hydroxide, from 0 to 30%. The rectification ratio and the reverse-current density of the ZnO:N/n-Si planar heterojunction were evaluated under dark condition for various NH4OH concentrations. The ZnO:N/n-Si heterojunction prepared with NH4OH 15% was found to have the lowest reverse-current density with a moderate resistivity. In order to realize an effective ZnO:N/n-Si photodiode, a ZnO:N layer prepared with 15% NH4OH was deposited on well-aligned Si nanowires. The core–shell NW photodiode showed more sensitive photodetecting performance in UV light than the planar photodiode. Also, the significantly enhanced performances of the core–shell NW photodiode were evaluated by examining its spectral responsivity.
Hereditary conditions that affect tooth enamel in quantity and/or quality are called amelogenesis imperfecta (AI). AI can occur as an isolated condition or as a symptom of a syndrome. An OMIM search ...with the term “AI” yielded 79 result entries. Mutations in the same gene cause syndromic or non-syndromic AI, depending on the nature of the mutations. In this study, we recruited two AI families and performed mutational analysis using whole-exome sequencing. The proband of family 1, with hypoplastic pitted AI and mild localized atopic dermatitis, had compound heterozygous COL17A1 mutations (paternal NM_000494.4: c.3598G>T, p.Asp1200Tyr and maternal c.1700G>A, p.Gly567Glu). The proband of family 2, with hypoplastic pitted AI and Jervell and Lange-Nielsen syndrome, had a recurrent LAMB3 mutation (NM_000228.3: c.3463_3475del, p.(Glu1155Thrfs*51)) in addition to compound heterozygous mutations in the KCNQ1 gene.
Age-related macular degeneration (AMD) is one of the leading causes of blindness in elderly individuals. However, the currently used intravitreal injections of anti-vascular endothelial growth factor ...are invasive, and repetitive injections are also accompanied by a risk of intraocular infection. The pathogenic mechanism of AMD is still not completely understood, but a multifactorial mechanism that combines genetic predisposition and environmental factors, including cellular senescence, has been suggested. Cellular senescence refers to the accumulation of cells that stop dividing due to the presence of free radicals and DNA damage. Characteristics of senescent cells include nuclear hypertrophy, increased levels of cell cycle inhibitors such as p16 and p21, and resistance to apoptosis. Senolytic drugs remove senescent cells by targeting the main characteristics of these cells. One of the senolytic drugs, ABT-263, which inhibits the antiapoptotic functions of Bcl-2 and Bcl-xL, may be a new treatment for AMD patients because it targets senescent retinal pigment epithelium (RPE) cells. We proved that it selectively kills doxorubicin (Dox)-induced senescent ARPE-19 cells by activating apoptosis. By removing senescent cells, the expression of inflammatory cytokines was reduced, and the proliferation of the remaining cells was increased. When ABT-263 was orally administered to the mouse model of senescent RPE cells induced by Dox, we confirmed that senescent RPE cells were selectively removed and retinal degeneration was alleviated. Therefore, we suggest that ABT-263, which removes senescent RPE cells through its senolytic effect, has the potential to be the first orally administered senolytic drug for the treatment of AMD.
Hereditary conditions that affect tooth enamel in quantity and/or quality are called amelogenesis imperfecta (AI). AI can occur as an isolated condition or as a symptom of a syndrome. An OMIM search ...with the term “AI” yielded 79 result entries. Mutations in the same gene cause syndromic or non-syndromic AI, depending on the nature of the mutations. In this study, we recruited two AI families and performed mutational analysis using whole-exome sequencing. The proband of family 1, with hypoplastic pitted AI and mild localized atopic dermatitis, had compound heterozygous COL17A1 mutations (paternal NM_000494.4: c.3598G>T, p.Asp1200Tyr and maternal c.1700G>A, p.Gly567Glu). The proband of family 2, with hypoplastic pitted AI and Jervell and Lange-Nielsen syndrome, had a recurrent LAMB3 mutation (NM_000228.3: c.3463_3475del, p.(Glu1155Thrfs*51)) in addition to compound heterozygous mutations in the KCNQ1 gene.
The process of tooth formation is a series of reciprocal interactions between the ectoderm and mesoderm, and it is believed that many genetic factors are involved in this complex process. More than a ...dozen genes have been identified in non-syndromic tooth agenesis; however, the genetic etiology underlying tooth agenesis is not fully understood yet. In this study, we identified two novel LRP6 mutations in two non-syndromic oligodontia families. Both probands had 16 and 17 missing teeth in their permanent dentition. Mutational analysis identified a de novo frameshift mutation by a 1-bp insertion in exon 9 (NM_002336.2: c.1870dupA, p.(Met624Asnfs*29)) and a splicing donor site mutation in intron 8 (c.1762+2T>C). An in vitro splicing assay confirmed the deletion of exon 8, and the deletion would result in a frameshift. Due to the premature termination codons introduced by the frameshift, both mutant transcripts would be degraded by nonsense-mediated mRNA decay, resulting in haploinsufficiency.
Age-related macular degeneration (AMD) is one of the leading causes of blindness in elderly individuals. However, the currently used intravitreal injections of anti-vascular endothelial growth factor ...are invasive, and repetitive injections are also accompanied by a risk of intraocular infection. The pathogenic mechanism of AMD is still not completely understood, but a multifactorial mechanism that combines genetic predisposition and environmental factors, including cellular senescence, has been suggested. Cellular senescence refers to the accumulation of cells that stop dividing due to the presence of free radicals and DNA damage. Characteristics of senescent cells include nuclear hypertrophy, increased levels of cell cycle inhibitors such as p16 and p21, and resistance to apoptosis. Senolytic drugs remove senescent cells by targeting the main characteristics of these cells. One of the senolytic drugs, ABT-263, which inhibits the antiapoptotic functions of Bcl-2 and Bcl-xL, may be a new treatment for AMD patients because it targets senescent retinal pigment epithelium (RPE) cells. We proved that it selectively kills doxorubicin (Dox)-induced senescent ARPE-19 cells by activating apoptosis. By removing senescent cells, the expression of inflammatory cytokines was reduced, and the proliferation of the remaining cells was increased. When ABT-263 was orally administered to the mouse model of senescent RPE cells induced by Dox, we confirmed that senescent RPE cells were selectively removed and retinal degeneration was alleviated. Therefore, we suggest that ABT-263, which removes senescent RPE cells through its senolytic effect, has the potential to be the first orally administered senolytic drug for the treatment of AMD.
Herein, the voltage and current output characteristics of a laser photovoltaic (PV) module applied to a wireless power transmission system using a laser beam are analyzed. First, an experiment is ...conducted to obtain the characteristic data of the voltage and current based on the laser output power of the laser PV module, which generates the maximum power from the laser beam at a wavelength of 1080 nm; subsequently, the small-signal voltage and current characteristics of the laser PV module are analyzed. From the analysis results, it is confirmed that the laser PV module has a characteristic in which the maximum power generation point varies according to the power level of the laser beam. In addition, similar to the solar cell module, it is confirmed that the laser PV module has a current source and a voltage source region, and it shows a small signal resistance characteristic having a negative value as the operating point goes to the current source region. In addition, in this paper, by reflecting these electrical characteristics, a method for designing the controller of a power converter capable of charging a battery while generating maximum power from a PV module is proposed. Since the laser PV module corresponds to the input source of the boost converter used as the power conversion unit, the small-signal transfer function of the boost converter, including the PV module, is derived for the controller design. Therefore, by designing a controller that can stably control the voltage of the PV module in the current source, the maximum power point, and voltage source regions defined according to the output characteristics of the laser PV module, the maximum power is generated from the PV module. Herein, a systematic controller design method for a boost converter for laser wireless power transmission is presented, and the proposed method is validated based on the simulation and experimental results of a 25-W-class boost converter based on a microcontroller unit control.
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