1,005 research outputs found

    Monitoring Water Resource Changes Using Multi-temporal Landsat Imagery Taken in Changnyeong, South Korea

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    AbstractMonitoring water resource changes is essential in water resources management and in flood or drought prevention. This research aims to monitor water resource changes using the multi-temporal Landsat imagery taken in December 2006 and 2014 through the following steps. First, the multiple NDWI (Normalized Difference Water Index) images are generated from the Landsat images. Next, multiple water resources such as the Nakdong River and the Dalchang reservoir are extracted from each NDWI image. Finally, the areas of the Nakdong River and the Dalchang reservoir in each NDWI image are measured to assess the water resource changes in the study area. The statistical results show that the Nakdong River had significantly increased its water storage capacity between 2006 and 2014, while the Dalchang reservoir had the constant area during the same period

    Effect of interlayer interactions on exciton luminescence in atomic-layered MoS2 crystals

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    The atomic-layered semiconducting materials of transition metal dichalcogenides are considered effective light sources with both potential applications in thin and flexible optoelectronics and novel functionalities. In spite of the great interest in optoelectronic properties of two-dimensional transition metal dichalcogenides, the excitonic properties still need to be addressed, specifically in terms of the interlayer interactions. Here, we report the distinct behavior of the A and B excitons in the presence of interlayer interactions of layered MoS 2 crystals. Micro-photoluminescence spectroscopic studies reveal that on the interlayer interactions in double layer MoS 2 crystals, the emission quantum yield of the A exciton is drastically changed, whereas that of the B exciton remains nearly constant for both single and double layer MoS 2 crystals. First-principles density functional theory calculations confirm that a significant charge redistribution occurs in the double layer MoS 2 due to the interlayer interactions producing a local electric field at the interfacial region. Analogous to the quantum-confined Stark effect, we suggest that the distinct behavior of the A and B excitons can be explained by a simplified band-bending model.1

    Decreased Angiopoietin Expression in Underactive Bladder Induced by Long-term Bladder Outlet Obstruction

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    Purpose Ischemia of the bladder can occur if neovascular formation cannot keep pace with hypoxia induced by chronic bladder outlet obstruction (BOO). The aim of this study was to examine changes in angiogenesis growth factor expression generated by chronic BOO in a rat model of underactive bladder. Methods Twenty female Sprague-Dawley rats aged 6 weeks were assigned to 4 groups (5 rats per group). Group 1 was the control. Group 2 underwent sham surgery. The rats in groups 3 and 4 underwent BOO and were followed up for 1 week and 8 weeks. Cystometry was carried out together with bladder tissue analysis at 1 week and 8 weeks postoperatively. Real-time polymerase chain reaction (PCR) assays were conducted to determine the expression level of angiogenesis-related growth factors. A hypoxia signaling pathway PCR array was additionally carried out. Results The group that underwent BOO for 8 weeks showed abnormal bladder function, with a diminished intercontraction interval, decreased maximal voiding pressure, and higher volume of residual urine (P<0.05). Hypoxia-inducible factor-1 alpha expression was elevated in this group. The expression levels of vascular endothelial growth factor (VEGF) and VEGF receptor messenger RNA (mRNA) in the BOO group were comparable to those in the control group. However, angiotensin/tie receptor mRNA expression levels increased at 1 week after BOO, but decreased at 8 weeks after BOO. In animals that underwent BOO, fewer blood vessels exhibited positive immunofluorescent staining for von Willebrand factor. Alterations were also seen in the hypoxia signaling pathway PCR array. Conclusions In a rat model of underactive bladder caused by surgical BOO, reduced angiopoietin expression was demonstrated. This observation might underlie visceral ischemia and fibrosis associated with the procedure. The findings of this study might offer an improved understanding of the disease processes underlying BOO and facilitate selection of the appropriate time to repair the organ in this condition

    Network analysis, in vivo, and in vitro experiments identified the mechanisms by which Piper longum L. [Piperaceae] alleviates cartilage destruction, joint inflammation, and arthritic pain

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    Osteoarthritis (OA) is characterized by irreversible joint destruction, pain, and dysfunction. Piper longum L. [Piperaceae] (PL) is an East Asian herbal medicine with reported anti-inflammatory, analgesic, antioxidant, anti-stress, and anti-osteoporotic effects. This study aimed to evaluate the efficacy of PL in inhibiting pain and progressive joint destruction in OA based on its anti-inflammatory activity, and to explore its potential mechanisms using in vivo and in vitro models of OA. We predicted the potential hub targets and signaling pathways of PL through network analysis and molecular docking. Network analysis results showed that the possible hub targets of PL against OA were F2R, F3, MMP1, MMP2, MMP9, and PTGS2. The molecular docking results predicted strong binding affinities for the core compounds in PL: piperlongumine, piperlonguminine, and piperine. In vitro experiments showed that PL inhibited the expression of LPS-induced pro-inflammatory factors, such as F2R, F3, IL-1ÎČ, IL-6, IL-17A, MMP-1, MMP-2, MMP-3, MMP-9, MMP-13, NOS2, PTGS2, PGE2, and TNF-ÎČ. These mechanisms and effects were dose-dependent in vivo models. Furthermore, PL inhibited cartilage degradation in an OA-induced rat model. Thus, this study demonstrated that multiple components of PL may inhibit the multilayered pathology of OA by acting on multiple targets and pathways. These findings highlight the potential of PL as a disease-modifying OA drug candidate, which warrants further investigation

    Differential Gene Expression in the Penile Cavernosum of Streptozotocin-Induced Diabetic Rats

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    Purpose Men with diabetes mellitus (DM) often present with severe erectile dysfunction (ED). This ED is less responsive to current pharmacological therapies. If we know the upregulated or downregulated genes of diabetic ED, we can inhibit or enhance the expression of such genes through RNA or gene overexpression. Methods To investigate gene changes associated with ED in type 1 DM, we examined the alterations of gene expression in the cavernosum of streptozotocin-induced diabetic rats. Specifically, we considered 11,636 genes (9,623 upregulated and 2,013 downregulated) to be differentially expressed in the diabetic rat cavernosum group (n=4) compared to the control group (n=4). The analysis of differentially expressed genes using the gene ontology (GO) classification indicated that the following were enriched: downregulated genes such as cell cycle, extracellular matrix, glycosylphosphatidylinositol-anchor biosynthesis and upregulated genes such as calcium signaling, neurotrophin signaling, apoptosis, arginine and proline metabolism, gap junction, transforming growth factor-ÎČ signaling, tight junction, vascular smooth muscle contraction, and vascular endothelial growth factor (VEGF) signaling. We examined a more than 2-fold upregulated or downregulated change in expression, using real time polymerase chain reaction. Analysis of differentially expressed genes, using the GO classification, indicated the enrichment Results Of the 41,105 genes initially considered, statistical filtering of the array analysis showed 9,623 upregulated genes and 2,013 downregulated genes with at least 2-fold changes in expression (P<0.05). With Bonferroni correction, SLC2A9 (solute carrier family 2 member 9), LRRC20 (leucine rick repeat containing 20), PLK1 (polo like kinase 1), and AATK (apoptosis-associated tyrosine kinase) were all 2-fold changed genes. Conclusions This study broadens the scope of candidate genes that may be relevant to the pathophysiology of diabetic ED. In particular, their enhancement or inhibition could represent a novel treatment for diabetic ED

    Gene-based copy number variation study reveals a microdeletion at 12q24 that influences height in the Korean population

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    AbstractHeight is a classic polygenic trait with high heritability (h2=0.8). Recent genome-wide association studies have revealed many independent loci associated with human height. In addition, although many studies have reported an association between copy number variation (CNV) and complex diseases, few have explored the relationship between CNV and height. Recent studies reported that single nucleotide polymorphisms (SNPs) are highly correlated with common CNVs, suggesting that it is warranted to survey CNVs to identify additional genetic factors affecting heritable traits such as height.This study tested the hypothesis that there would be CNV regions (CNVRs) associated with height nearby genes from the GWASs known to affect height. We identified regions containing >1% copy number deletion frequency from 3667 population-based cohort samples using the Illumina HumanOmni1-Quad BeadChip. Among the identified CNVRs, we selected 15 candidate regions that were located within 1Mb of 283 previously reported genes. To assess the effect of these CNVRs on height, statistical analyses were conducted with samples from a case group of 370 taller (upper 10%) individuals and a control group of 1828 individuals (lower 50%).We found that a newly identified 17.7kb deletion at chromosomal position 12q24.33, approximately 171.6kb downstream of GPR133, significantly correlated with height; this finding was validated using quantitative PCR. These results suggest that CNVs are potentially important in determining height and may contribute to height variation in human populations

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    Passed a Wittness of the Faith, Scientist, a Servant of The Lord, True Priest: Nicefor Petrashevich (1915–2013), canon of the Preshov Greek Catholic Eparchy. Abstract Decease of the witness of the Faith, a servant of the Lord and a famous researcher of the religious folklore: Nicefor Joseph Petrashevich (1915–2013) distinguished member of the Capitol of Preshov Greek Catholic Eparchy. Born in Čukalovce, East-Slovakia (then CsukalĂłc, Upper-Hungary) in 1915 as the sixth of the eleven children in the family of a Greek Catholic bishop, he was inspired by his father and elder brother who served the Lord. He studied in the high school (gymnasium) of the Cistercian Order in Eger (Northern Hungary) which provided its pupils with knowledge and deep faith. He became a choir-minister of the Uzghorod Bishopric Basilica where he turned to the examination of folklore traditions reflected in the liturgical chants. Apparently, it was his calling and his findings on the Byzantine chants contributed significantly to the understanding of religious folklore. He was known as a gift ed composer and singer, too. The Greek Catholic Church was banned in the Soviet Union which obtained Subcarpathia after the World War II, and this church was oppressed in Slovakia as well, so he faced a dilemma: to convert to the Ortodox (Pravoslav) Christianity and live free, or to remain faithful to the Catholic Church and be persecuted. Moreover, he was a coelebs, a priest who did not have a wife (despite the fact that Greek Catholic priests are allowed to have families). Consequently, he could have been elected as bishop, as the higher ranks in the Byzantine Churches are open for monks. The communist authorities offered Father Nicefor the episcopate of the Slovak Ortodox Church, if he converted to the Ortodoxy. He refused it: “my head does not accept the mithra (bishops’ crone) by leaving my Catholic faith” –he said. As a result, he was imprisoned for more than two years in Slovakia. Later he came to Hungary where could not serve as a parochial priest, but worked as cantor or helping pope in various places and in centres of pilgrimage where performed the liturgy in Church Slavonic which he sang excellently. Continuing his researches in the folk sings in the liturgy and the local traditions of the liturgical chants, he gained a small grant of the Soros Foundation in 1986 and delivered lectures for two semesters at the Department of the Folklore at the Eötvös University in Budapest in 1988–89. His papers have been partially published, but most of them are still preserved as manuscripts in the Institute of Musicology at the Hungarian Academy of Sciences, or even in unknown places worldwide, as he sent his works to his brothers-in-faith to the United States. In his eighties, instead of enjoying the golden days of ageing, he moved to Slovakia in order to serve as a pastor who spoke both Slovakian and Hungarian as mother tongues. He was buried in SzikszĂł, Hungary where the Greek Catholic Bishop of Preshov and approximately forty popes from Ukraine, Hungary and Slovakia commemorated him on 20 July 2013. Church historians and folklorists honored his memory as a researcher with a conference on 4 October 2013 in SzikszĂł. Proceedings are to be published next year. A memorial website about him is open for bloggers

    Chronic airway disease as a major risk factor for fractures in osteopenic women: Nationwide cohort study

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    IntroductionThe study aimed to demonstrate the risk factors for fractures and to develop prediction models for major osteoporotic and hip fractures in osteopenic patients using the nationwide cohort study in South Korea.MethodsThe study was a retrospective nationwide study using the national screening program for transitional ages from the National Health Insurance Services database in Korea from 2008 to 2019. Primary outcomes were incident fracture events of major osteoporotic and hip fractures. Major osteoporotic and hip fracture events were defined as diagnostic and procedural codes. Patients were followed until the fragility fractures, death, or 2019, whichever came first.ResultsAll participants were 66-year-old females, with a mean body mass index was 25.0 ± 3.1 kg/m2. During a median follow-up of 10.5 years, 26.9% and 6.7% of participants experienced major osteoporotic and hip fractures. In multivariate analysis, a history of fracture, chronic airway disease, falls, diabetes mellitus and cerebrovascular diseases were significant risk factors for major osteoporotic (hazard ratio [HR] 2.35 for a history of fracture; 1.17 for chronic airway disease; 1.10 for falls; 1.12 for diabetes mellitus; 1.11 for cerebrovascular disease) and hip fractures (HR 1.75 for a history of fracture; 1.54 for diabetes mellitus; 1.27 for cerebrovascular disease; 1.17 for fall; 1.15 for chronic airway disease). The performances of the prediction models were area under the receiver operating curve of 0.73 and 0.75 for major osteoporotic and hip fractures.ConclusionThe study presented prediction models of major osteoporotic and hip fractures for osteopenia patients using simple clinical features

    Genetic Analyses of the Chimeric CYP11B1/CYP11B2 Gene in a Korean Family with Glucocorticoid-Remediable Aldosteronism

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    Glucocorticoid-remediable aldosteronism (GRA) is an autosomal-dominant inheritable form of hyperaldosteronism with early onset hypertension. GRA is caused by unequal crossing-over of the steroid 11ÎČ-hydroxylase (CYP11B1) and aldosterone synthase (CYP11B2) genes. As a result of chimeric gene duplication, aldosterone is ectopically synthesized in the adrenal zona fasciculata under the control of adrenocorticotropin. Here, we describe three cases of GRA in a Korean family. The proband-a 21-yr-old female-was incidentally found to have high blood pressure (170/108 mmHg). Her 46-yr-old father had been treated twice for cerebral hemorrhage at the ages of 29 and 39 yr. Her 15-yr-old brother had a 2-yr history of hypertension; however, he was never treated. Their laboratory test results showed normokalemia, hyporeninemia, hyperaldosteronism, and a high plasma aldosterone concentration-to-plasma renin activity ratio. Normal saline loading failed to suppress aldosterone secretion. However, dexamethasone administration effectively suppressed their plasma aldosterone concentrations. Following genetic analyses with PCR and direct sequencing to document the chimeric gene and crossover site, respectively, we identified CYP11B1/CYP11B2 and determined the breakpoint of unequal crossover to be located between intron 2 of CYP11B1 and exon 3 of CYP11B2

    Quantitative local probing of polarization with application on HfO 2 ‐based thin films

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    Owing to their switchable spontaneous polarization, ferroelectric materials have been applied in various fields, such as information technologies, actuators, and sensors. In the last decade, as the characteristic sizes of both devices and materials have decreased significantly below the nanoscale, the development of appropriate characterization tools became essential. Recently, a technique based on conductive atomic force microscopy (AFM), called AFM‐positive‐up‐negative‐down (PUND), is employed for the direct measurement of ferroelectric polarization under the AFM tip. However, the main limitation of AFM‐PUND is the low frequency (i.e., on the order of a few hertz) that is used to initiate ferroelectric hysteresis. A significantly higher frequency is required to increase the signal‐to‐noise ratio and the measurement efficiency. In this study, a novel method based on high‐frequency AFM‐PUND using continuous waveform and simultaneous signal acquisition of the switching current is presented, in which polarization–voltage hysteresis loops are obtained on a high‐polarization BiFeO3 nanocapacitor at frequencies up to 100 kHz. The proposed method is comprehensively evaluated by measuring nanoscale polarization values of the emerging ferroelectric Hf0.5Zr0.5O2 under the AFM tip
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