The geology of North Korea: An overview Zhai, Mingguo; Zhang, Xiao-Hui; Zhang, Yan-Bin ...
Earth-science reviews,
July 2019, 2019-07-00, Letnik:
194
Journal Article
Recenzirano
The Korean Peninsula (KP) occupies a junction area of three big tectonic domains that are the Paleo-Central Asian Orogenic Belt, Paleo-Tethyan Orogenic Belt and the Western Pacific Orogenic Belt. ...Therefore the KP is a key area to understand the Northeast Asian and even global geotectonic evolution. In terms of geological unit division, the KP has long been thought to be closely tied with the mainland of China, with using collective term the Sino-Korea Craton for the North China Craton (NCC). However, such correlation suffered from the absence of relevant geological information in North Korea (NK). To bridge this knowledge gap, our group carries out a long-term collaborative study between the two-sides of the KP and China，and organized united field investigation in the North Korea, South Korea (SK) and China as possible. This paper introduces general geology in the North Korea，and simply make comparison with the NCC and South Korea. These pioneering works culminated in the following summaries. (1) The KP comprises three major Precambrian massifs, i.e., Rangnim, Gyeonggi and Yeongnam massifs. The Rangnim and Gyeonggi massifs are separated by the Imjingang Structural Belt, while the Gyeonggi and Yeongnam massifs are separated by the Ogcheon Structural Belt. (2) The basement of the Rangnim massif is correlated with that of the NCC. The characteristic metamorphic rocks of high- temperature/high-pressure granulite facies including meta- sedimentary rocks (kondalites and meta-sandstones and marbles) with ~1.9–1.8 Ga metamorphic ages occur in the three massifs, similar to the NCC. (3) The Proterozoic rift sedimentary sequences are developed in the NCC and North Korea, but Lower Paleoproterozoic strata are rare, and Neoproterozoic strata are more developed in North Korea relative to the NCC. (4) Two main Paleozoic basins within the Rangnim massif and within the Gyeonggi and Yeongnam massifs are the Phyongnam basin and Taebaeksan Basin. Both of them have a similar Paleozoic tectono-stratigraphy to the NCC. (5) Although the nature and tectonic significance of the Imjingang belt remains controversial, it doesn't show characteristics and natures of collisional orogenic belt. (6) The eclogite-bearing Hongseong Complex (HSC) is located in the southwestern part of the Gyeonggi Massif in South Korea, but no similar rock unit has been found in North Korea. (7) Mesozoic igneous rocks are widespread throughout the northern and southern parts of the KP. Triassic magmatism is related to Indosinian orogeny. Jurassic and Cretaceous igneous rocks are different and irregular from those in the NCC on age and spatial-temporal distribution. This paper also suggests several key and controversial academic issues that are worthwhile to study in the future.
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•The Archean Rangrim massif is divideded into the Rangrim and Kwanmo submassifs, high-grade region and greenstone belt, respectively.•Early Paleoproterozoic rocks underwent metamorphism up to granulite facies, which may be correlated to the Jiao-Liao-Ji mobile belt in the NCC.•Proterozoic rift sequences in North Korea are similar to those in the NCC with rare late Paleoproterozoic strata and more Neoproterozoic strata.•Both main Paleozoic basins, the Phyongnam basin in NK and the Taebaeksan Basin in SK, have a similar Paleozoic tectono-stratigraphy to the NCC.•Mesozoic igneous rocks are extensively distributed in the KP.
Congenital muscular dystrophies (CMDs) are clinically and genetically heterogeneous conditions. We launched a nationwide study to determine the frequency of CMD in the Chinese population and assess ...the status of diagnosis and disease management for CMD in China. Cases were chosen from databases in 34 tertiary academic hospitals from 29 first‐level administrative divisions (provinces, municipalities, autonomous regions, and special administrative regions), and medical records were reviewed to confirm the diagnoses. The study included 409 patients, of those patients who consented to genetic testing (n = 340), mutations were identified in 286 of them. The most common forms identified were LAMA2‐related CMD (36.4%), followed by COL6‐related CMD (23.2%) and α‐dystroglycanopathy (21.0%). The forms of CMD related to mutations in LMNA and SEPN1 were less frequent (12.5% and 2.4%, respectively). We also recorded a significant difference in the diagnostic capabilities and disease management of CMD, with this being relatively backward in research centers from less developed regions. We provide, for the first time, comprehensive epidemiologic information of CMD in a large cohort of Chinese people. To our knowledge, this is the largest sample size of its kind so far highlighting the prevalence of CMD in China.
The properties of materials are intricately dependent on their chemical composition, and microstructures. Achieving a precise modulation in the composition and microstructure of materials to enhance ...properties significantly is a huge challenge. In this work, we uncovered the effects of nickel and silicon composition on the precipitates, dislocations, and properties of Cu–Ni–Si alloys. The results show that the volume fraction of precipitates increased from 0.84 % to 4.80 % with the increase of Ni and Si contents. The average diameter of the precipitates increased from 6.20 nm to 20.21 nm, and the dislocation density increased from 2.16 × 1013 m−2 to 4.08 × 1015 m−2 concerning the Ni and Si contents. In addition, the dislocation type changes from half-edge dislocation and half-screw dislocation to screw dislocation. The modified WHWA (Williamson Hall-Warren Averbach) method was proved to be the most accurate way of calculating dislocation density. As anisotropy was present in the alloy, adding a dislocation contrast factor and removing some lower-intensity diffraction peaks could further correct the obtained results and reduce the calculation error. Furthermore, the above analysis and findings were employed to design a Cu-3.21Ni-0.66Si alloy with a high yield strength (814 MPa), high ultimate tensile strength (970 MPa), and comparable electrical conductivity of 42.4 % IACS. This work offers a meaningful way to develop precipitation-strengthening alloys.
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This paper investigates the efficient robust design and optimization of a high-temperature superconducting (HTS) linear synchronous motor by using the Taguchi parameter design approach. The ...manufacturing tolerances of the HTS magnets, primary iron core and the air gap are considered in the robust design to ensure that the optimal design is less sensitive to these uncertainties. To overcome the disadvantages of the conventional Taguchi parameter design approach, a sequential Taguchi robust optimization method is presented for improvement of the motor performance and manufacturing quality. The proposed method is efficient because it holds the advantages of both Taguchi method and sequential optimization strategy. It can significantly increase the average thrust and decrease the thrust ripple of the investigated HTS linear synchronous motor.
Enzymatic decarboxylation and carboxylation are emerging as prospective processes to produce high-value compounds under mild conditions. Ferulic acid decarboxylase Fdc1 catalyzes broad substrate ...tolerance against α, β-unsaturated carboxylic acids, and provides green routes for carbon dioxide fixation with the reversible carboxylation, while the activity of the enzyme is limited by the indispensable cofactor prenylated flavin (prFMN), which is unstable and is rarely detected in nature. In this study, a prFMN efficient synthesis route was built using six exogenous enzymes introduced into E. coli cells, leading to the construction of a powerful cell catalyst named SC-6. Based on the metabolic analysis, the results indicated that the reduction of FMN to FMNHsub.2 was the bottleneck in prFMN synthesis pathway, and introducing FMN reductase increased the production of prFMN 3.8-fold compared with the common flavin prenyltransferase UbiX overexpression strain. Using SC-6 cell catalyst, the decarboxylation activity of Fdc1 increased more than 20 times with cinnamic acid and 4-acetoxycinnamic acid as substrates. Furthermore, the reversible carboxylation reaction was carried out, and the cell catalyst presented 20 times carbon dioxide fixation activity using styrene to produce cinnamic acid. Finally, the maximum yield of cinnamic acid catalyzed by SC-6 achieved 833.68 ± 34.51 mM·mgsup.−1 in two hours. The constructed prFMN pathway in vivo provides fundamentals for efficient decarboxylation and carbon fixation reactions catalyzed by prFMN-dependent enzymes.
Hydrogen production from ethanol solution (initial ethanol concentration of 50%) by pulsed discharge coupled with TiO2 is investigated in this work. Strong ultraviolet light is emitted by pulsed ...discharge in liquid, which makes photocatalysis have a great prospect in plasma reforming. Two kinds of TiO2 are attempted, containing non-metal ion doping and Ag deposition. The results show that the flow rate of hydrogen produced by pulsed discharge with TiO2 coated non-metal can be achieved 1.55 L/min, which is higher than with TiO2 coated Ag, but both two are higher than discharge without TiO2. From SEM analysis, it may be associated with the larger specific surface area of TiO2 coated non-metal. However, percentage concentration of hydrogen produced with TiO2 coated Ag is higher than others, which can be attained 78%. It may be due to the high work function of Ag. In addition, mechanism of hydrogen produced by pulsed discharge coupled with TiO2 is also analyzed. It demonstrates that the increase of ·H is the main reason for increased hydrogen yield.
•Hydrogen produced by pulsed discharge coupled with TiO2 was studied.•The flow rate of hydrogen was increased about 0.55 times with TiO2 coated non-metal.•The percentage concentration of hydrogen was increased about 4% with TiO2 coated Ag.•The more free radical ·H was formed, the more hydrogen was produced.•Mechanism of hydrogen produced by pulsed discharge coupled with TiO2 was analyzed.
Background
Lung cancer is a high incidence cancer on a worldwide basis and has become a major public health problem. Lung adenocarcinoma (LUAD) makes up approximately half of all lung cancers and is ...a threat to human health. Long non-coding RNAs (lncRNAs) is an important regulator of the development and progression of lung adenocarcinoma. In this manuscript we examined the role and potential mechanism of lncRNA PCAT6 in the development of LUAD.
Methods and results
Differences in lncRNA PCAT6 levels between LUAD samples and normal samples were first explored in the GEPIA database. We found that lncRNA PCAT6 expression was elevated, which was also validated in lung adenocarcinoma tissues and cell lines. Using western blotting, CCK-8, EdU, wound healing and transwell assays, we found that knockdown of lncRNA PCAT6 inhibited EMT, proliferation, migration, and invasion of LUAD cells. We noted a predicted a binding site for lncRNA PCAT6 and miR-545-3p through conducting bioinformatic analyses, and their binding was subsequently verified by a dual-luciferase reporter assay. Rescue experiments confirmed that miR-545-3p inhibitor partially abolished the inhibition function of lncRNA PCAT6 knockdown on LUAD cells. In addition, we predicted the downstream target genes of miR-545-3p and verified them by RT-qPCR. We found that EGFR was reduced in the silence of lncRNA PCAT6 and upregulated after miR-545-3p inhibition.
Conclusion
This study demonstrates that lncRNA PCAT6 promotes a more aggressive LUAD phenotype by sponging miR-545-3p. This finding may provide new ideas for the treatment of lung cancer.
This study aimed to analyze the correlation between bone mineral density (BMD) and bone resorption markers in postmenopausal women with osteoporosis fractures and identify risk factors for second ...fractures.
This retrospective analysis of 1,239 older women with fractures with a median age of 70 years who attended Shanghai General Hospital from January 2007 to December 2016, included a first fracture group (1,008 cases) and a second fractures group (231 cases). The risk factors for fractures were analyzed by comparing these groups on clinical characteristics, BMD, and bone metabolism markers stratified by quartiles of serum C-terminal telopeptide of type 1 collagen (CTX). Binary logistic regression analysis was used to identify risk factors for second fractures.
In the whole sample, BMD was negatively correlated with age and serum osteocalcin and positively correlated with body mass index (BMI). In women with first fractures, those in the highest quartile of serum CTX had the lowest spine and hip BMD. Second fractures were significantly associated with BMI, lower spine and hip BMD, and higher serum osteocalcin but not CTX. Binary logistic regression analysis showed that high BMI (odds ratio OR, 1.08 95% CI, 1.03-1.14; P = 0.001), low lumbar BMD (OR, 0.24 95% CI, 0.07-0.82; P = 0.023), low total hip BMD (OR, 0.05 95% CI, 0.00-0.88; P = 0.041), and lack of antiosteoporosis treatment (OR, 2.71 95% CI, 2.71-4.08; P < 0.001) were independent risk factors for second fractures.
In older women with fractures, BMD was significantly lower in women with second fractures than in those with first fractures. Higher levels of serum CTX and osteocalcin, which indicates increased bone resorption, were negatively correlated with BMD. In women with a first fracture, serum CTX higher than 605 pg/mL was negatively correlated with BMD, whereas no correlation was found between different CTX and BMD in women with second fractures. High BMI and low BMD as well as not receiving antiosteoporosis treatment were independent risk factors for second fractures.
Vitamin D could be beneficial for healthy ageing in humans. We previously found that vitamin D supplementation may slow down epigenetic ageing in young African American adults. We tested new ...epigenetic clocks developed for neonates among a multiethnic population, and tested the hypothesis that maternal vitamin D supplementation would slow down the epigenetic gestational age acceleration (GAA) in newborn babies. Ninety-two pregnant women (aged 29.6 ± 4.8 y; 21% African Americans, 28% Hispanics) were randomized to receive 4000 IU/day vitamin D
3
or placebo, plus prenatal vitamins containing 400 IU vitamin D
3
during pregnancy in a randomized controlled trial (RCT). Cord blood genome-wide methylation analysis was performed on the Illumina Infinium MethylationEPIC Beadchip. DNA methylation gestational age was calculated based on two calculations developed by Knight and Bohlin. DNA methylation gestational ages calculated by Knight's clock and Bohlin' clock were highly correlated with the gestational age in the placebo group (correlation coefficients = 0.88, p s< 0.001, respectively). GAA was associated with higher birth weight (p = 0.039). In the entire cohort, vitamin D
3
supplementation was not associated with GAA (p > 0.05). However, vitamin D
3
supplementation decreased GAA by both Knight's clock (β = −0.89, p = 0.047) and Bohlin's clock (β = −0.71, p = 0.005) in the African American participants. Maternal vitamin D
3
supplementation may slow down the epigenetic gestational ageing process in African American neonates. Long-term follow-up studies are warranted to determine the role of epigenetic age acceleration in the growth and development of offspring.
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