Publications by authors named "Renyu Hu"

Hot Jupiters are among the best-studied exoplanets, but it is still poorly understood how their chemical composition and cloud properties vary with longitude. Theoretical models predict that clouds may condense on the nightside and that molecular abundances can be driven out of equilibrium by zonal winds. Here we report a phase-resolved emission spectrum of the hot Jupiter WASP-43b measured from 5 μm to 12 μm with the JWST's Mid-Infrared Instrument.

View Article and Find Full Text PDF

Characterizing rocky exoplanets is a central aim of astronomy, and yet the search for atmospheres on rocky exoplanets has so far resulted in either tight upper limits on the atmospheric mass or inconclusive results. The 1.95R and 8.

View Article and Find Full Text PDF

The recent inference of sulfur dioxide (SO) in the atmosphere of the hot (approximately 1,100 K), Saturn-mass exoplanet WASP-39b from near-infrared JWST observations suggests that photochemistry is a key process in high-temperature exoplanet atmospheres. This is because of the low (<1 ppb) abundance of SO under thermochemical equilibrium compared with that produced from the photochemistry of HO and HS (1-10 ppm). However, the SO inference was made from a single, small molecular feature in the transmission spectrum of WASP-39b at 4.

View Article and Find Full Text PDF

Seven rocky planets orbit the nearby dwarf star TRAPPIST-1, providing a unique opportunity to search for atmospheres on small planets outside the Solar System. Thanks to the recent launch of the James Webb Space Telescope (JWST), possible atmospheric constituents such as carbon dioxide (CO) are now detectable. Recent JWST observations of the innermost planet TRAPPIST-1 b showed that it is most probably a bare rock without any CO in its atmosphere.

View Article and Find Full Text PDF
Article Synopsis
  • Photochemistry plays a critical role in regulating the composition and stability of planetary atmospheres, but clear photochemical products have not been detected in exoplanets until recently.* -
  • The James Webb Space Telescope (JWST) detected sulfur dioxide (SO) in the atmosphere of the exoplanet WASP-39b, suggesting photochemical processes create SO in this gas giant's atmosphere.* -
  • The presence of SO, linked to the oxidation of hydrogen sulfide, indicates WASP-39b has high metallicity (about 10 times that of the sun), and its spectral features could help understand more about similar exoplanets.*
View Article and Find Full Text PDF
Article Synopsis
  • Measuring the metallicity and carbon-to-oxygen (C/O) ratio in exoplanet atmospheres helps to understand their chemical processes and formation history.
  • The James Webb Space Telescope (JWST) allows for advanced observations of exoplanets, notably WASP-39b, providing insights through time-series data with high precision in a new wavelength range.
  • Findings include the detection of water vapor in the atmosphere with a high metallicity (1-100 times that of the Sun) and a low C/O ratio, suggesting the potential for significant solid material accretion during formation or chemical disequilibrium in the atmosphere.
View Article and Find Full Text PDF

Measuring the abundances of carbon and oxygen in exoplanet atmospheres is considered a crucial avenue for unlocking the formation and evolution of exoplanetary systems. Access to the chemical inventory of an exoplanet requires high-precision observations, often inferred from individual molecular detections with low-resolution space-based and high-resolution ground-based facilities. Here we report the medium-resolution (R ≈ 600) transmission spectrum of an exoplanet atmosphere between 3 and 5 μm covering several absorption features for the Saturn-mass exoplanet WASP-39b (ref.

View Article and Find Full Text PDF

The Mars Science Laboratory (MSL) recently discovered nitrates in Gale Crater (, Stern , 2015; Sutter , 2017). One possible mechanism for ancient nitrate deposition on Mars is through HNOx formation and rain out in the atmosphere, for which lightning-induced NO is likely the fundamental source. This study investigates nitrogen (N) fixation in early Mars' atmosphere, with implications for early Mars' habitability.

View Article and Find Full Text PDF

Geological evidence shows that ancient Mars had large volumes of liquid water. Models of past hydrogen escape to space, calibrated with observations of the current escape rate, cannot explain the present-day deuterium-to-hydrogen isotope ratio (D/H). We simulated volcanic degassing, atmospheric escape, and crustal hydration on Mars, incorporating observational constraints from spacecraft, rovers, and meteorites.

View Article and Find Full Text PDF

Lung cancer is one of the leading causes of cancer-related death worldwide. The most common type of lung cancer is non-small cell lung cancer (NSCLC). When NSCLC is detected, patients are typically already in a metastatic stage.

View Article and Find Full Text PDF

Cancer metastasis is the major cause of death in pancreatic cancer. We have established a pair of pancreatic ductal adenocarcinoma cell line, PANC1 and invasive PANC1-I5, as a model system toinvestigate the metastatic mechanism as well as potential therapeutic targets in pancreatic cancer. We used proteomic analysis based on two-dimensional differential gel electrophoresis (2D-DIGE) and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) to examine the global protein expression alterations between PANC1 and PANC1-I5.

View Article and Find Full Text PDF

A long-term goal of exoplanet studies is the identification and detection of biosignature gases. Beyond the most discussed biosignature gas O, only a handful of gases have been considered in detail. In this study, we evaluate phosphine (PH).

View Article and Find Full Text PDF

Most known terrestrial planets orbit small stars with radii less than 60 per cent of that of the Sun. Theoretical models predict that these planets are more vulnerable to atmospheric loss than their counterparts orbiting Sun-like stars. To determine whether a thick atmosphere has survived on a small planet, one approach is to search for signatures of atmospheric heat redistribution in its thermal phase curve.

View Article and Find Full Text PDF

Recent measurements of methane (CH) by the Mars Science Laboratory (MSL) now confront us with robust data that demand interpretation. Thus far, the MSL data have revealed a baseline level of CH (∼0.4 parts per billion by volume [ppbv]), with seasonal variations, as well as greatly enhanced spikes of CH with peak abundances of ∼7 ppbv.

View Article and Find Full Text PDF

In the coming years and decades, advanced space- and ground-based observatories will allow an unprecedented opportunity to probe the atmospheres and surfaces of potentially habitable exoplanets for signatures of life. Life on Earth, through its gaseous products and reflectance and scattering properties, has left its fingerprint on the spectrum of our planet. Aided by the universality of the laws of physics and chemistry, we turn to Earth's biosphere, both in the present and through geologic time, for analog signatures that will aid in the search for life elsewhere.

View Article and Find Full Text PDF

Unlabelled: The Curiosity rover recently detected a background of 0.7 ppb and spikes of 7 ppb of methane on Mars. This in situ measurement reorients our understanding of the martian environment and its potential for life, as the current theories do not entail any geological source or sink of methane that varies sub-annually.

View Article and Find Full Text PDF

Over the past decade, observations of giant exoplanets (Jupiter-size) have provided key insights into their atmospheres, but the properties of lower-mass exoplanets (sub-Neptune) remain largely unconstrained because of the challenges of observing small planets. Numerous efforts to observe the spectra of super-Earths--exoplanets with masses of one to ten times that of Earth--have so far revealed only featureless spectra. Here we report a longitudinal thermal brightness map of the nearby transiting super-Earth 55 Cancri e (refs 4, 5) revealing highly asymmetric dayside thermal emission and a strong day-night temperature contrast.

View Article and Find Full Text PDF

The oral cancer cell line OC3-I5 with a highly invasive ability was selected and derived from an established OSCC line OC3. In this study, we demonstrated that matrix metalloproteinases protein MMP-13 was up-regulated in OC3-I5 than in OC3 cells. We also observed that expression of epithelial-mesenchymal transition (EMT) markers including Twist, p-Src, Snail1, SIP1, JAM-A, and vinculin were increased in OC3-I5 compared to OC3 cells, whereas E-cadherin expression was decreased in the OC3-I5 cells.

View Article and Find Full Text PDF

The climate of Mars likely evolved from a warmer, wetter early state to the cold, arid current state. However, no solutions for this evolution have previously been found to satisfy the observed geological features and isotopic measurements of the atmosphere. Here we show that a family of solutions exist, invoking no missing reservoirs or loss processes.

View Article and Find Full Text PDF

Chemotherapy is one of the major categories of medical oncology and a primary tumor treatment; however, the effectiveness of chemotherapy is restricted by drug resistance. Overcoming resistance to chemotherapy and investigating molecular targeted therapies are challenges currently faced during resistance management. Progesterone receptor membrane component 1 (PGRMC1) is an adapter protein mediating cholesterol synthesis, steroid signaling, and cytochrome p450 activation.

View Article and Find Full Text PDF

Drug resistance is a frequent cause of failure in cancer chemotherapy treatments. In this study, a pair of uterine sarcoma cancer lines, MES-SA, and doxorubicin-resistant partners, MES-SA/DxR-2μM cells and MES-SA/DxR-8μM cells, as a model system to investigate resistance-dependent proteome alterations and to identify potential therapeutic targets. We used two-dimensional differential gel electrophoresis (2D-DIGE) and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) to perform this research and the results revealed that doxorubicin-resistance altered the expression of 208 proteins in which 129 identified proteins showed dose-dependent manners in response to the levels of resistance.

View Article and Find Full Text PDF

Neuroendocrine cervical cancer is an aggressive but rare form of cervical cancer. The majority of neuroendocrine cervical cancer patients present with advanced-stage diseases. However, the limited numbers of neuroendocrine tumor markers are insufficient for clinical purposes.

View Article and Find Full Text PDF

Background: Cancer has continually been the leading cause of death worldwide for decades. Thus, scientists have actively devoted themselves to studying cancer therapeutics. Doxorubicin is an efficient drug used in cancer therapy, but also produces reactive oxygen species (ROS) that induce severe cytotoxicity against heart cells.

View Article and Find Full Text PDF