Graduate Research
Search for signs of life beyond Earth
The question of whether or not life exists beyond Earth has motivated the search for biosignatures within and beyond our Solar system. Biosignatures are substances or phenomena that provide evidences of present or past life.
Through the extensive studies of terrestrial biological systems, the evidences of life have observed as features across multiple spatial scales, such as biologically-relevant organic compounds (i.e., biomarkers) and their molecular structures, enantiomeric excesses, isotopic and elemental abundance patterns, and morphologies of fossils and microbial mats.
Future space missions with a primary focus to search for life elsewhere (i.e., life-detection missions) leverage these characteristics as prospective biosignatures, requesting mission-enabling technologies and innovative analytical techniques that offer highly sensitive (low limit of detection), reproducible (high precision), and reliable (low risks of contamination) biosignatures measurements in situ in order to constitute convincing evidences of indigenous life.
Through the extensive studies of terrestrial biological systems, the evidences of life have observed as features across multiple spatial scales, such as biologically-relevant organic compounds (i.e., biomarkers) and their molecular structures, enantiomeric excesses, isotopic and elemental abundance patterns, and morphologies of fossils and microbial mats.
Future space missions with a primary focus to search for life elsewhere (i.e., life-detection missions) leverage these characteristics as prospective biosignatures, requesting mission-enabling technologies and innovative analytical techniques that offer highly sensitive (low limit of detection), reproducible (high precision), and reliable (low risks of contamination) biosignatures measurements in situ in order to constitute convincing evidences of indigenous life.
I am interested in coevolution of planets and life. My research aims to
- understand the evolutionary history of planetary environments through trace element analyses,
- identify versatile instrumentation and explore innovative analytical techniques that enable in situ detection and characterization of biosignatures,
- define reliable and robust proxies to distinguish the source and origins of prospective biosignatures.
ASMS (2021)!
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Simultaneous Measurements of Mass and Collisional Cross-Section of Single Ions with Orbitrap Mass Spectrometry for Exploratory Data Analysis
Recent development of using transient decay from an orbitrap analyzer to infer molecular collision cross section (CCS) has enabled characterization of unknown compounds with both mass and structure. However, current method requires pure samples and exact pressure and temperature conditions of the orbitrap chamber for accurate CCS calculation, which imposes many constraints in studying sample mixtures in the field. How to enable simultaneous measurements of mass and CCS, just based on spectral information, becomes the key success of exploratory data analysis via orbitrap mass spectrometry. Central to this puzzle is a fundamental understanding of ion motions inside an orbitrap analyzer and the development of a comprehensive model that corrects for erroneous transient decay under perturbed experimental conditions.
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Detection and Characterization of Biosignatures via Laser-Enabled Orbitrap Mass Spectrometry
The laser-enabled Orbitrap mass spectrometer, an instrument configuration that constitutes a state-of-art Orbitrap analyzer in coupled to a highly capable laser system, has demonstrated its capability of unambiguous identification of biomarkers and geologic phases on planetary surfaces. This study aims to explore three innovative techniques to constrain the uncertainty of detected biomarkers without requirements of additional apparatus. These techniques are (1) in source decay via adjustment of laser fluence, (2) determination of molecular collision cross section via transient decay, and (3) characterization of mass in space via imaging mass spectrometry.
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Earth's Redox History in ZirconZircon is a robust accessory mineral commonly found in felsic rocks. The Ce/Ce* and Ti content in zircon can be used to infer the redox states of local magmatic environments from which they crystallized. This study presents a simple filter scheme that facilitates the selection of mantle‐equilibrated zircon to infer mantle redox states.
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Evolution of Spaceflight Mass SpectrometrySince the inception of mass spectrometry, the field has matured as analytical capabilities have progressed, instrument configurations multiplied, and applications proliferated. Here, we provide a short review on the development of mass analyzers and supporting subsystems that have significant heritage in spaceflight applications, and we introduce a selection of emerging technologies that may enable new and/or augmented mission concepts in the coming decades.
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Making Prebiotic Organics from Hadean Crust via Hypervelocity impactsPrevious studies suggest exogenous infall might not just deliver organics but also enable molecular synthesis in the plasma plume after hypervelocity impacts (HVIs). In particular, HCN is of high astrobiological interest. Though previous HVIs studies have emphasized the roles of carbonaceous and nitrogenous gases at synthesizing HCN, this study is the first to show HCN production in vacuum, demonstrating that geological substrates and carbonaceous impactors alone can also contribute quantitatively to the formation of HCN.
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Click to check my AGU talk (2020)!
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Characterizing biopatterns via Laser Desorption IonizationWe rely on our robotic friends (like the Curiosity Mars rover) to search for evidence of life in planetary environments. We gave them flexible wheels, chuncky body, powerful arms, and most importantly, a pair of insightful eyes. In this talk, we will briefly overview the traditional "eyes" that have been used in historical missions, and highlight the potentials and challenges of using laser ablation mass spectrometry as future "eyes" to detect and characterize biopatterns.
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Undergraduate Research
Loyalhanna FormationLoyalhanna Formation is a Mississippian calcareous sandstone that is regarded as one of valuable rock for road aggregate in Pennsylvania. In this research, we analyzed the major element concentration and examined petrographics through the log, and developed a depositional setting for the formation.
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Fe-S and Mo IncorporationIron-sulfur is a complex but extremely important system to understand the anoxia history of earth and the origin of life. In this research, we focused on the formation of mackinawite, transformation of mackinawite to gregite and pyrite, and incorporation of Mo to these minerals.
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Etruscan CeramicsThe Etruscan civilization was one of the most powerful and wealthy civilization of ancient Italy. The study of ceramics at Etruscan sites, in conjunction with quantitative geochemical analysis for mineralogical composition and trace element concentrations, can help archeologists to achieve a more comprehensive understanding of ancient cultures and lives.
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