Synthesis and Characterization of Folic Acid Labeled Upconversion Fluorescent Nanoprobes for in vitro Cancer Cells Targeted Imaging

Ming Huang,Lijun Wang,Xiaojuan Zhang,Jin Zhou,Lihua Liu,Yuefang Pan,Bin Yu,ZHANGSEN YU 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2017 NANO Vol.12 No.5

Upconversion nanoparticles (UCNPs) are widely used in the field of biomedicine, such as biosensing, cell labeling and medical multimodal imaging because of their unique optical properties. In this paper, we demonstrated the synthesis of polyethylenimine-modified NaLuF4:Yb,Er (RE = Lu 0.78, Yb 0.18, Er 0.02) UCNPs in three different solvents, such as water, ethylene glycol and diethylene glycol. The as-prepared UCNPs were characterized and the experimental results showed that the UCNPs synthesized in ethylene glycol had excellent properties. The obtained UCNPs in ethylene glycol had the smallest particle size and uniform size distribution, and the pure cubic phase of crystallization and Dynamic light scattering and particle dispersion index (DLS/Pdi) were the smallest. What's more, the upconversion fluorescence intensity was 7 and 52 times greater than that of UCNPs synthesized in diethylene glycol and water, respectively. In addition, the factors of reaction solvent that had an impact on the particle size, morphology, crystalline phase, DLS and upconversion fluorescence intensity of the synthesized UCNPs were discussed. Moreover, in order to obtain the targeted nanoprobe, we used an EDC/NHS covalent coupling method to modify folic acid to the NaLuF4:Yb,Er/PEI UCNP surface. The NaLuF4:Yb, Er/PEI–FA upconversion fluorescent nanoprobes had low cytotoxicity and were suitable for the application in HeLa cells targeted fluorescent imaging.

High-mass Starless Clumps in the Inner Galactic Plane: The Sample and Dust Properties

Yuan, Jinghua,Wu, Yuefang,Ellingsen, Simon P.,II, Neal J. Evans,Henkel, Christian,Wang, Ke,Liu, Hong-Li,Liu, Tie,Li, Jin-Zeng,Zavagno, Annie American Astronomical Society 2017 The Astrophysical journal Supplement series Vol.231 No.1

<P>We report a sample of 463 high-mass starless clump (HMSC) candidates within -60 degrees < l < 60 degrees and -1 degrees < b < 1 degrees. This sample has been singled out from 10,861 ATLASGAL clumps. None of these sources are associated with any known star-forming activities collected in SIMBAD and young stellar objects identified using color-based criteria. We also make sure that the HMSC candidates have neither point sources at 24 and 70 mu m. nor strong extended emission at 24 mu m. Most of the identified HMSCs are infrared dark, and some are even dark at 70 mu m. Their distribution shows crowding in Galactic spiral arms and toward the Galactic center and some wellknown star-forming complexes. Many HMSCs are associated with large-scale filaments. Some basic parameters were attained from column density and dust temperature maps constructed via fitting far-infrared and submillimeter continuum data to modified blackbodies. The HMSC candidates have sizes, masses, and densities similar to clumps associated with Class II methanol masers and H. II. regions, suggesting that they will evolve into star-forming clumps. More than 90% of the HMSC candidates have densities above some proposed thresholds for forming high-mass stars. With dust temperatures and luminosity-to-mass ratios significantly lower than that for star-forming sources, the HMSC candidates are externally heated and genuinely at very early stages of high-mass star formation. Twenty sources with equivalent radii r(eq) < 0.15 pc and mass surface densities Sigma > 0.08 g cm(-2) could be possible high-mass starless cores. Further investigations toward these HMSCs would undoubtedly shed light on comprehensively understanding the birth of high-mass stars.</P>

DENSE GAS IN MOLECULAR CORES ASSOCIATED WITH<i>PLANCK</i>GALACTIC COLD CLUMPS

Yuan (袁敬华,), Jinghua,Wu, Yuefang,Liu, Tie,Zhang, Tianwei,Li, Jin Zeng,Liu, Hong-Li,Meng, Fanyi,Chen, Ping,Hu, Runjie,Wang, Ke American Astronomical Society 2016 The Astrophysical journal Vol.820 No.1

<P>We present the first survey of dense gas toward Planck Galactic Cold Clumps (PGCCs). Observations in the J = 1-0 transitions of HCO+ and HCN toward 621 molecular cores associated with PGCCs were performed using the Purple Mountain Observatory's 13.7 m telescope. Among them, 250 sources were detected, including 230 cores detected in HCO+. and 158 in HCN. Spectra of the J = 1-0 transitions from (CO)-C-12, (CO)-C-13, and (CO)-O-18 at the centers of the 250 cores were extracted from previous mapping observations to construct a multi-line data set. The significantly low detection rate of asymmetric double-peaked profiles, together with the good consistency among central velocities of CO, HCO+, and HCN spectra, suggests that the CO-selected Planck cores are more quiescent than classical star-forming regions. The small difference between line widths of (CO)-O-18. and HCN indicates that the inner regions of CO-selected Planck cores are no more turbulent than the exterior. The velocity-integrated intensities and abundances of HCO+ are positively correlated with those of HCN, suggesting that these two species are well coupled and chemically connected. The detected abundances of both HCO+ and HCN are significantly lower than values in other low- to high-mass star-forming regions. The low abundances may be due to beam dilution. On the basis of an inspection of the parameters given in the PGCC catalog, we suggest that there may be about 1000 PGCC objects that have a sufficient reservoir of dense gas to form stars.</P>

ALMA Reveals Sequential High-mass Star Formation in the G9.62+0.19 Complex

Liu, Tie,Lacy, John,Li, Pak Shing,Wang, Ke,Qin, Sheng-Li,Zhang, Qizhou,Kim, Kee-Tae,Garay, Guido,Wu, Yuefang,Mardones, Diego,Zhu, Qingfeng,Tatematsu, Ken’ichi,Hirota, Tomoya,Ren, Zhiyuan,Liu, Sheng-Yu American Astronomical Society 2017 The Astrophysical journal Vol.849 No.1

<P>Stellar feedback from high-mass stars (e.g., H II regions) can strongly influence the surrounding interstellar medium and regulate star formation. Our new ALMA observations reveal sequential high-mass star formation taking place within one subvirial filamentary clump (the G9.62 clump) in the G9.62+0.19 complex. The 12 dense cores (MM1-MM12) detected by ALMA are at very different evolutionary stages, from the starless core phase to the UC H II region phase. Three dense cores (MM6, MM7/G, MM8/F) are associated with outflows. The mass-velocity diagrams of the outflows associated with MM7/G and MM8/F can be well-fit by broken power laws. The mass-velocity diagram of the SiO outflow associated with MM8/F breaks much earlier than other outflow tracers (e.g., CO, SO, CS, HCN), suggesting that SiO traces newly shocked gas, while the other molecular lines (e.g., CO, SO, CS, HCN) mainly trace the ambient gas continuously entrained by outflow jets. Five cores (MM1, MM3, MM5, MM9, MM10) are massive starless core candidates whose masses are estimated to be larger than 25 M-circle dot, assuming a dust temperature of <= 20 K. The shocks from the expanding H II regions ('B' and 'C') to the west may have a great impact on the G9.62 clump by compressing it into a filament and inducing core collapse successively, leading to sequential star formation. Our findings suggest that stellar feedback from H II regions may enhance the star formation efficiency and suppress low-mass star formation in adjacent pre-existing massive clumps.</P>

Aerodynamic topology optimization on tip configurations of turbine blades

Min Zhang,Yan Liu,Jinguang Yang,Yuefang Wang 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.7

The topology optimization (TopOpt) is adopted in this article to design tip geometries of a turbine blade. Its principle is to modify the porosity, which is one for fluid and is zero for solid. A CFD method coupled with source terms is implemented for numerical simulations. Moreover, to update the porosity, a quasi-sensitivity and an adjoint sensitivity analysis schemes are integrated with the method of moving asymptotes algorithm, respectively. The TopOpt is conducted to design the tip profile of a 2D tip model and of nine axial sections in a 3D turbine blade. Optimized tips are reconstructed and their performance is verified by experiments and CFD. Results indicate that the re-designed novel tip, which has a convexconcave-convex form and is different from flat and cavity tips, has good performance due to getting rid of flow separations above the tip. Hence, the optimized tip can lower total pressure loss in the gap region.

High-mass Star Formation through Filamentary Collapse and Clump-fed Accretion in G22

Yuan, Jinghua,Li, Jin-Zeng,Wu, Yuefang,Ellingsen, Simon P.,Henkel, Christian,Wang, Ke,Liu, Tie,Liu, Hong-Li,Zavagno, Annie,Ren, Zhiyuan,Huang, Ya-Fang American Astronomical Society 2018 The Astrophysical journal Vol.852 No.1

<P>How mass is accumulated from cloud-scale down to individual stars is a key open question in understanding highmass star formation. Here, we present the mass accumulation process in a hub-filament cloud G22 that is composed of four supercritical filaments. Velocity gradients detected along three filaments indicate that they are collapsing with a total mass infall rate of about 440M(circle dot) Myr(-1), suggesting the hub mass would be doubled in six free-fall times, adding up to similar to 2 Myr. A fraction of the masses in the central clumps C1 and C2 can be accounted for through large-scale filamentary collapse. Ubiquitous blue profiles in HCO+. (3-2) and (CO)-C-13. (3-2) spectra suggest a clump-scale collapse scenario in the most massive and densest clump C1. The estimated infall velocity and mass infall rate are 0.31 km s(-1) and 7.2 x. 10(-4)M(circle dot) yr(-1), respectively. In clump C1, a hot molecular core (SMA1) is revealed by the Submillimeter Array observations and an outflow-driving high-mass protostar is located at the center of SMA1. The mass of the protostar is estimated to be 11-15M(circle dot) and it is still growing with an accretion rate of 7 x. 10(-5)M(circle dot) yr(-1). The coexistent infall in filaments, clump C1, and the central hot core in G22 suggests that pre-assembled mass reservoirs (i.e., high-mass starless cores) may not be required to form high-mass stars. In the course of high-mass star formation, the central protostar, the core, and the clump can simultaneously grow in mass via core-fed/disk accretion, clump-fed accretion, and filamentary/cloud collapse.</P>

The TOP-SCOPE Survey of <i>Planck</i> Galactic Cold Clumps: Survey Overview and Results of an Exemplar Source, PGCC G26.53+0.17

Liu, Tie,Kim, Kee-Tae,Juvela, Mika,Wang, Ke,Tatematsu, Ken’ichi,Francesco, James Di,Liu, Sheng-Yuan,Wu, Yuefang,Thompson, Mark,Fuller, Gary,Eden, David,Li, Di,Ristorcelli, I.,Kang, Sung-ju,Lin, Yuxin Published by the University of Chicago Press for t 2018 The Astrophysical journal Supplement series Vol.234 No.2

<P>The low dust temperatures (< 14 K) of Planck Galactic cold clumps (PGCCs) make them ideal targets to probe the initial conditions and very early phase of star formation. 'TOP-SCOPE' is a joint survey program targeting similar to 2000 PGCCs in J = 1-0 transitions of CO isotopologues and similar to 1000 PGCCs in 850 mu m continuum emission. The objective of the 'TOP-SCOPE' survey and the joint surveys (SMT 10 m, KVN 21 m, and NRO 45 m) is to statistically study the initial conditions occurring during star formation and the evolution of molecular clouds, across a wide range of environments. The observations, data analysis, and example science cases for these surveys are introduced with an exemplar source, PGCC G26.53+0.17 (G26), which is a filamentary infrared dark cloud (IRDC). The total mass, length, and mean line mass (M/L) of the G26 filament are similar to 6200 M-circle dot, similar to 12 pc, and similar to 500 M-circle dot pc(-1), respectively. Ten massive clumps, including eight starless ones, are found along the filament. The most massive clump as a whole may still be in global collapse, while its denser part seems to be undergoing expansion owing to outflow feedback. The fragmentation in the G26 filament from cloud scale to clump scale is in agreement with gravitational fragmentation of an isothermal, nonmagnetized, and turbulent supported cylinder. A bimodal behavior in dust emissivity spectral index (beta) distribution is found in G26, suggesting grain growth along the filament. The G26 filament may be formed owing to large-scale compression flows evidenced by the temperature and velocity gradients across its natal cloud.</P>

The Properties of Planck Galactic Cold Clumps in the L1495 Dark Cloud

Tang, Mengyao,Liu, Tie,Qin, Sheng-Li,Kim, Kee-Tae,Wu, Yuefang,Tatematsu, Ken’ichi,Yuan, Jinghua,Wang, Ke,Parsons, Harriet,Koch, Patrick M.,Sanhueza, Patricio,Ward-Thompson, D.,Tó,th, L. Viktor,S American Astronomical Society 2018 The Astrophysical journal Vol.856 No.2

STAR FORMATION LAWS IN BOTH GALACTIC MASSIVE CLUMPS AND EXTERNAL GALAXIES: EXTENSIVE STUDY WITH DUST CONINUUM, HCN (4-3), AND CS (7-6)

Liu, Tie,Kim, Kee-Tae,Yoo, Hyunju,Liu, Sheng-yuan,Tatematsu, Ken’ichi,Qin, Sheng-Li,Zhang, Qizhou,Wu, Yuefang,Wang, Ke,Goldsmith, Paul F.,Juvela, Mika,Lee, Jeong-Eun,Tó,th, L. Viktor,Mardones, D American Astronomical Society 2016 The Astrophysical journal Vol.829 No.2

<P>We observed 146 Galactic clumps in HCN (4-3) and CS (7-6) with the Atacama Submillimeter Telescope Experiment 10 m telescope. A tight linear relationship between star formation rate and gas mass traced by dust continuum emission was found for both Galactic clumps and the high redshift (z > 1) star forming galaxies (SFGs), indicating a constant gas depletion time of similar to 100 Myr for molecular gas in both Galactic clumps and high z SFGs. However, low z galaxies do not follow this relation and seem to have a longer global gas depletion time. The correlations between total infrared luminosities (L-TIR) and molecular line luminosities (L-mol') of HCN (4-3) and CS (7-6) are tight and sublinear extending down to clumps with L-TIR similar to 10(3) L-circle dot. These correlations become linear when extended to external galaxies. A bimodal behavior in the L-TIR-L-mol' correlations was found for clumps with different dust temperature, luminosity-to-mass ratio, and sigma(line)/sigma(vir). Such bimodal behavior may be due to evolutionary effects. The slopes of L-TIR-L-mol' correlations become more shallow as clumps evolve. We compared our results with lower J transition lines in Wu et al. (2010). The correlations between clump masses and line luminosities are close to linear for low effective excitation density tracers but become sublinear for high effective excitation density tracers for clumps with L-TIR larger than L-TIR similar to 10(4.5) L-circle dot. High effective excitation density tracers cannot linearly trace the total clump masses, leading to a sublinear correlations for both M-clump-L-mol' and L-TIR-L-mol' relations.</P>