Lipid biomarkers and stable carbon isotopes can track the evolution of microbial communities and carbon cycling, respectively, in preserved organic matter. Traditionally, carbon isotopes are measured in bulk materials, though technological advances allow us to measure the carbon isotope composition of individual hydrocarbon molecules, providing direct insights into the carbon source and microbial metabolism used for biosynthesis. During sedimentary diagenesis, lipids are incorporated into a complex macromolecular matrix—(proto)-kerogen. Lipids associated with or tightly bound within the kerogen matrix are not routinely analysed, thus a large repository of geochemical information relating to mode of binding and preservation remains unexplored.

Presented here are two studies of marine organic matter preservation and cycling, from the enigmatic late Ediacaran Shuram excursion of South Oman and from the modern hypersaline microbial mats of Guerrero Negro, Baja California, Mexico.

From South Oman, we present the first detailed bulk isotope, lipid biomarker, and compound-specific carbon isotope compilation from an organic-rich, deeper water facies that captures the unique ‘Shuram excursion’—a carbon isotope excursion in carbonate (down to -12‰) that is not paralleled in magnitude by the coeval organic carbon phases. Our results definitively demonstrate that preserved organic matter is syngenetic and marine-derived and has two distinct organic carbon isotopic sources. The extractable alkane hydrocarbons preserve a smaller overall magnitude carbon isotope excursion in phase with a primary surface seawater origin.

From Guerrero Negro, we investigated kerogen-bound lipid biomarker profiles from two cores of different salinity and compare them to lipids extracted using conventional techniques. Additionally, to investigate the mode of binding and incorporation of sterols and hopanoids into kerogen during diagenesis, we extracted kerogen-bound lipids of pre-extracted microbial mat residues that were subjected to three selective chemical degradations. Our findings indicate a suite of lipid biomarkers, including sterols and hopanoids, are rapidly incorporated into kerogen via strong covalent linkages and preserved during sedimentary diagenesis. The absence of sterols or other polycyclic biomarker compounds classes is unlikely the result of taphonomic bias in periods of Earth history where benthic organic matter source inputs are pronounced.

"Asian American Activism: 1960s to the Present" is designed to navigate and unpack the various grassroots movements and collective efforts that shape Asian American history. "Celebrating Asian American Women" will analyze the intersections of race and gender within the parameters of Asian American feminisms, immigration, labor, refugees, war, and family formation. “Asian American Perspectives on Alternative Healing Modalities” examines the history, techniques, and critiques of alternative healing modalities that originated in the regions of China, India, and Japan and further transformed into contemporary practices in the United States.

According to the World Health Organization (WHO) in year 2015 alone, 18 million people died from cardiovascular-related diseases, which makes for a staggering 31% of all global deaths. Recent studies of human cardiomyocytes in-vitro have been generating scientific insights beyond traditional approaches. However, in general, human cardiomyocytes are difficult to study due to limited sample availability and due to its fragile in-vitro nature. In this work, we studied HL-1 cells, a tumor-cell derived cardiomyocyte, to ultimately quantify the relationship between cell contractility and to investigate the influence of external stimuli. The motivation behind this study was to look into cardiomyocyte contractility as a quantifiable indicator for cardiotoxicity.

We first tried to understand the implications of biomechanical cues on cardiomyocyte orientation. HL-1 cells have the ability to grow in-vitro indefinitely while maintaining the ability to rhythmically contract autonomously upon reaching confluence. We found that HL-1 cells can mimic the characteristics of human cardiomyocyte, making them an excellent candidate for proof-of-concept demonstrations. They differ from human cardiomyocyte in that they lack a natural orientation and striation in-vitro. With the success of integrating substrates to incorporate nanoscale precision surface textures and which allow tissue engineering, the physiological environment of cells and tissues can be re-capitulated in-vitro. The purpose of this research was to align HL-1 cells on a polymer substrate to quantify their uniform contractility. We created an effective platform to observe cardiac contractility where the HL-1 cells are mechanically supported on a polymer substrate micro-machined with patterned grooves and ridges of nanoscale precision. Herein, we report on the quantitative efficiency of HL-1 cardiomyocyte alignment on various micro-patterned surfaces. The experimental results suggest that our micro-platform can promote cardiomyocyte alignment in-vitro, which is a crucial intermediate step towards rapid drug screening for cardiotoxicity.