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Cancer is a universal disease with a high mortality rate and caused by an uncontrolled growth of abnormal cells. Each cancer has its unique molecular change such as up/down-regulations of biological molecules in cancer cells. These biological molecules have been identified as biomarkers and used as a target analyte for cancer diagnosis. Since the level of cancer biomarkers is very insufficient at an early stage cancer, there is a need for technological advances that can be more accurate, ultra-sensitive, trustworthy, and selective to biomarkers. This review summarizes evaluation methods and recent advances in electrochemical and optical (fluorescent and colorimetric) biosensors to detect various cancer biomarkers as molecular targets. Electrochemical methods demonstrate rapid and ultra-sensitive detection of cancer biomarkers. And, fluorescent biosensors present improved target detection sensitivity by signal amplification strategy as well as provide the possibility to sense multiple biomarker targets with multiple fluorescent probes. Colorimetric biosensors easily and quickly detect cancer biomarkers by the naked eye for use as a point-of-care testing (POCT) platform. These biosensors can be further improved by understanding the complication of cancer cells and the molecular alterations in cancer progression for early diagnosis of cancer and patient prognosis. [ABSTRACT FROM AUTHOR]

The Gongsuwon thrust together with the Deokpori (Gakdong) thrust in northeastern Okcheon belt is considered to be an important structure in understanding the tectonic evolution of the Korean peninsula following the Permian-Triassic collision between North and South China continents. We obtained Rb-Sr ages for Paleozoic sedimentary rocks around the Gongsuwon thrust to determine the age of petrographically observed thermal metamorphism and possibly constrain the movement age of the thrust. Andalusite, codierite and biotite porphyroblasts overgrow cataclastic foliation of siliceous fault rocks in the Gongsuwon thrust, indicating a post-faulting thermal metamorphism. A marble of the early Paleozoic Makgol Formation in the hanging wall (∼200 m northwest from the fault zone center) and a siliceous cataclasite in the fault zone center gave Cretaceous Rb-Sr whole rock fragment ages: 113±21 (2σ) Ma and 68±17 (2σ) Ma, respectively. Sandstones of the late Paleozoic Hambaeksan Formation in the footwall (about 680 m southeast from the fault zone center) yielded an early Tertiary Rb-Sr biotite age of 56.3±6.0 (2σ) Ma, but a Paleoproterozoic Rb-Sr muscovite age of 1774±30 (2σ) Ma, suggesting that the early Tertiary thermal effect for the sandstones was strong enough to reset the Rb-Sr biotite age but weak enough not to affect the Rb-Sr muscovite age, i.e., between ∼300°C and ∼500°C, and that detrital muscovites in the sandstones were derived from the Precambrian basement rocks. These isotopic ages suggest that there was Cretaceous to early Tertiary thermal event around the Gongsuwon thrust, which is probably associated with well-known plutonism at that time (so-called Bulguksa granite). Available age data, albeit limited, suggest that Cretaceous to early Tertiary thermal metamorphism in the Taebaeksan basin might have been extensive. The movement age of the Gongsuwon thrust is constrained to be older than ∼60 Ma. [ABSTRACT FROM AUTHOR]

NE trending granitoid batholiths in South Korea are part of the huge Phanerozoic granitoid belt in east Asia. The crystallization ages of granitoid plutons show three episodes of Mesozoic magmatism in South Korea: Triassic (248-210 Ma), Jurassic (197-158 Ma), and Late Cretaceous-early Tertiary (110-50 Ma), with a Late Jurassic-Early Cretaceous (∼50 m.y.) hiatus. The granitoid ages and kinematic analyses of the Mesozoic structures in South Korea suggest that the Middle Jurassic (180-170 Ma) dextral strike-slip ductile shear zones formed by the northwest (orthogonal) subduction of the Izanagi plate, whereas the Cretaceous sinistral faults formed by the northward (oblique) subduction of the same plate, which generally agree with proposed reconstruction of plate motions, albeit uncertain, around east Asia. Among the models proposed to explain magmatic lull in a continental arc, shallow angle subduction associated with high convergence rate and subduction of oceanic plateaus might be the probable cause for the magmatic hiatus in South Korea and Japan. The huge width (∼500 km) of the east Asian granitoid belt may be explained by oceanward retreat of subduction zone in the Cretaceous in association with change in the movement direction of the subducting plate. [ABSTRACT FROM AUTHOR]

Abstract We present chemical and Sr–Nd–Pb isotopic compositions of three Triassic (226–241 Ma) calc-alkaline granitoids (the Yeongdeok granite, Yeonghae diorite and Cheongsong granodiorite) and basement rocks in the northern Gyeongsang basin, south-eastern Korea. These plutons exhibit typical geochemical characteristics of I-type granitoids generated in a continental magmatic arc. The Yeongdeok and Yeonghae plutons have similar initial Sr, Nd and Pb isotope ratios (87 Sr/86 Srinitial = 0.7041 ~ 0.7050, ℇNd (t) = 2.3 ~ 4.0, 206 Pb/204 Pbfeldspar = 18.22 ~ 18.34), but distinct rare earth element patterns, suggesting that the two plutons formed from partial melting of a similar source material at different depths. The Cheongsong pluton has slightly more enriched Sr–Nd–Pb isotopic compositions (87 Sr/86 Srinitial = 0.7047 ~ 0.7065, ℇNd (t) = 3.9 ~ 2.8, 206 Pb/204 Pbfeldspar = 18.24 ~ 18.37) than the other two plutons. The Nd model ages of the basement rocks (1.1 ~ 1.4 Ga) are slightly older than those of the plutons (0.6 ~ 1.0 Ga). The initial Sr and Nd isotopic ratios of the plutons can be modeled by the mixing between the mid-oceanic ridge basalt-like depleted mantle component and the crustal component represented by basement rocks, which is also supported by Pb isotope data. The Sr and Nd isotope data from granitoids and basement rocks suggest that the Gyeongsang basin, the Hida belt and the inner zone of south-western Japan share relatively young basement histories (middle Proterozoic), compared with those (early Proterozoic to Archean) of the Gyeonggi and Yeongnam massifs and the Okcheon belt. The Nd isotope data of basement rocks suggest that the Hida belt might be better correlated with the basement of the Gyeongsang basin than the Gyeonggi massif, the Okcheon... [ABSTRACT FROM AUTHOR]

We report a ring dike of Jurassic granite for the first time in Korea. There is a prominent circular structure in Seoul granitic batholith near Uijongbu, north of Seoul. The circular structure consists of large eastern half-circle (ca. 13 km in diameter) and small western half-circle (ca. 6 km in diameter) divided by a north-south-striking fault. A comparison with recently available geologic maps indicates that the geologic structure corresponds to a ring dike (or cone sheet) of garnet biotite granite, which negates an impact origin. We suggest that the Uijongbu structure was formed by differential weathering between resistant garnet biotite granite and easily weathered biotite granite. A ring dike origin for the Uijongbu structure probably associated with a volcanic cauldron subsidence is supported by rather shallow emplacement depth for the Jurassic granite and fast cooling rate (ca. 100°C/Ma) estimated from mineral ages, although no associated volcanics are present in the surrounding region. [ABSTRACT FROM AUTHOR]

The Busan gneiss complex is a unique body in the Okchon Belt in that it consists of high-grade gneisses surrounded by low-grade schists. In order to elucidate the origin of the Busan gneiss complex, we compared Pb isotope data from the complex with those from the nearby Bagdalryeong gneiss complex of the Kyongki Massif. The two complexes share common lithology, i.e., migmatitic gneiss and augen gneiss. The Pb data of whole rock and feldspar from the two complexes appear to form a single linear array in the207Pb/204Pb–206Pb/204Pb diagram, corresponding to an age of 2932±65 (1σ) Ma. It represents either the formation age or the age of high-grade metamorphism, i.e., migmatization. The Th/U ratios calculated from the208Pb/204Pb and206Pb/204Pb data of both complexes show a close relationship in lithology. The Pb isotope data suggest that the two complexes were originally one continuous body and experienced a similar geologic history since the early Proterozoic. Thus, we conclude that the Busan gneiss complex is either an extension of the basement rocks of the Kyongki Massif beneath the Okchon Belt or a tectonically emplaced piece of the Kyongki Massif. We reinterpret reported Rb−Sr muscovite and biotite ages for the Busan and Bagdalryeong gneiss complexes as the cooling age. The Rb−Sr muscovite ages were originally interpreted as the reset (or partially reset) ages during the Triassic metamorphism of the Okchon Belt (Cliff et al., 1985). Our alternative interpretation suggests that the Bagdalryeong gneiss complex was uplifted rapidly during the Jurassic, whereas the Busan gneiss complex was uplifted slowly since the late Permian. The fast uplift of the Bagdalryeong gneiss complex might have been related to the normal shear movement between the Kyongki Massif and the Okchon Belt (Ree et al., 1995). [ABSTRACT FROM AUTHOR]