Accelerated structural evolution of galaxies in a starbursting cluster at z=2.51

Structural properties of cluster galaxies during their peak formation epoch, $z \sim 2-4$ provide key information on whether and how environment affects galaxy formation and evolution. Based on deep HST/WFC3 imaging towards the z=2.51 cluster, J1001, we explore environmental effects on the structure, color gradients, and stellar populations of a statistical sample of cluster SFGs. We find that the cluster SFGs are on average smaller than their field counterparts. This difference is most pronounced at the high-mass end ($M_{\star} > 10^{10.5} M_{\odot}$) with nearly all of them lying below the mass-size relation of field galaxies. The high-mass cluster SFGs are also generally old with a steep negative color gradient, indicating an early formation time likely associated with strong dissipative collapse. For low-mass cluster SFGs, we unveil a population of compact galaxies with steep positive color gradients that are not seen in the field. This suggests that the low-mass compact cluster SFGs may have already experienced strong environmental effects, e.g., tidal/ram pressure stripping, in this young cluster. These results provide evidence on the environmental effects at work in the earliest formed clusters with different roles in the formation of low and high-mass galaxies.Comment: 13 pages, 10 figures, 1 tabl

Noema formIng Cluster survEy (NICE): Discovery of a starbursting galaxy group with a radio-luminous core at z=3.95

The study of distant galaxy groups and clusters at the peak epoch of star formation is limited by the lack of a statistically and homogeneously selected and spectroscopically confirmed sample. Recent discoveries of concentrated starburst activities in cluster cores have opened a new window to hunt for these structures based on their integrated IR luminosities. Hereby we carry out the large NOEMA (NOrthern Extended Millimeter Array) program targeting a statistical sample of infrared-luminous sources associated with overdensities of massive galaxies at z>2, the Noema formIng Cluster survEy (NICE). We present the first result from the ongoing NICE survey, a compact group at z=3.95 in the Lockman Hole field (LH-SBC3), confirmed via four massive (M_star>10^10.5M_sun) galaxies detected in CO(4-3) and [CI](1-0) lines. The four CO-detected members of LH-SBC3 are distributed over a 180 kpc physical scale, and the entire structure has an estimated halo mass of ~10^13Msun and total star formation rate (SFR) of ~4000Msun/yr. In addition, the most massive galaxy hosts a radio-loud AGN with L_1.4GHz, rest = 3.0*10^25W/Hz. The discovery of LH-SBC3 demonstrates the feasibility of our method to efficiently identify high-z compact groups or forming cluster cores. The existence of these starbursting cluster cores up to z~4 provides critical insights into the mass assembly history of the central massive galaxies in clusters.Comment: 7 pages, 7 figures, submitted to A&

Strategic Insider Trading: Disguising Order Flows to Escape Trading Competition

Short sellers actively exploit trading opportunities from insider sales. We argue that, in response to concern about potential order flow information leakage, insiders strategically disguise their order flows to escape trading competition. Our model predicts that, when short sellers are sensitive to order flow information, insiders are more likely to adopt a cautious trading strategy, i.e., splitting their trades over time. Empirically, we identify cautious trading by tracking consecutive transactions at the insider-strategy level. We find that, when anticipating intensive short selling potential, (1) insiders tend to trade cautiously; and (2) cautious insiders tend to reduce their initial trades. Overall, we highlight the strategic interaction between insiders and short sellers on the diffusion of order flow information

Strategic insider trading: Disguising order flows to escape trading competition

Short sellers actively exploit trading opportunities from insider sales. We argue that, in response to concern about potential order flow information leakage, insiders strategically disguise their order flows to escape trading competition. Our model predicts that, when short sellers are sensitive to order flow information, insiders are more likely to adopt a cautious trading strategy, i.e., splitting their trades over time. Empirically, we identify cautious trading by tracking consecutive transactions at the insider-strategy level. We find that, when anticipating intensive short selling potential, (1) insiders tend to trade cautiously; and (2) cautious insiders tend to reduce their initial trades. Overall, we highlight the strategic interaction between insiders and short sellers on the diffusion of order flow information

Development of a New Hydrogen Sulfide Fluorescent Probe Based on Coumarin–Chalcone Fluorescence Platform and Its Imaging Application

Hydrogen sulfide (H2S), as one of the critical gaseous signaling molecules, has important physiological functions in the human body, and abnormal levels of hydrogen sulfide are closely related to tumors, Parkinson’s disease, Alzheimer’s disease, and other diseases. In order to enable the detection of H2S in the physiological environment, herein, a new H2S fluorescence probe, named C-HS, based on a coumarin–chalcone fluorescence platform was developed. The fluorescence probe provides specific recognition of H2S within a wide pH detection range (5.5–8.5), a rapid recognition response (within 10 min) for H2S molecules, and a high selectivity for competing species. The probe C-HS possesses low cytotoxicity and is used to achieve the detection of exogenous/ endogenous H2S in living cells, indicating that the constructed probe C-HS has the ability to track changes in intracellular H2S levels. Therefore, probe C-HS could be a potential tool for the early diagnosis of H2S-related diseases

Mussel-Inspired Polydopamine Coated Iron Oxide Nanoparticles for Biomedical Application

Mussel-inspired polydopamine (PDA) coated iron oxide nanoparticles have served as a feasible, robust, and functional platform for various biomedical applications. However, there is scarcely a systemic paper reviewed about such functionalising nanomaterials to date. In this review, the synthesis of iron oxide nanoparticles, the mechanism of dopamine self-oxidation, the interaction between iron oxide and dopamine, and the functionality and the safety assessment of dopamine modified iron oxide nanoparticles as well as the biomedical application of such nanoparticles are discussed. To enlighten the future research, the opportunities and the limitations of functionalising iron oxide nanoparticles coated with PDA are also analyzed

Synthesis of Superparamagnetic Iron Oxide Nanoparticles Modified with MPEG-PEI via Photochemistry as New MRI Contrast Agent

Novel method for synthesis of superparamagnetic iron oxide nanoparticles (SPIONs) coated with polyethylenimine (PEI) and modified with poly(ethylene glycol) methyl ether (MPEG), MPEG-PEI-SPIONs, was developed. PEI-SPIONs were successfully prepared in aqueous system via photochemistry, and their surface was modified with poly(ethylene glycol) methyl ether (MPEG). The so-obtained MPEG-PEI-SPIONs had a uniform hydrodynamic particle size of 34 nm. The successful coating of MPEG-PEI on the SPIONs was ascertained from FT-IR analysis, and the PEI and MPEG fractions in MPEG-PEI-SPIONs were calculated to account for 31% and 12%, respectively. Magnetic measurement revealed that the saturated magnetization of MPEG-PEI-SPIONs reached 46 emu/g and the nanoparticles showed the characteristic of being superparamagnetic. The stability experiment revealed that the MPEG-PEI modification improved the nanoparticles stability greatly. T2 relaxation measurements showed that MPEG-PEI-SPIONs show similar R2 value to the PEI-SPIONs. The T2-weighted magnetic resonance imaging (MRI) of MPEG-PEI-SPIONs showed that the magnetic resonance signal was enhanced significantly with increasing nanoparticle concentration in water. These results indicated that the MPEG-PEI-SPIONs had great potential for application in MRI