Josiah Yarbrough
MD Student, expected graduation Winter 2028
Graduate CELC, Haas Center for Public Service
Education & Certifications
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Doctor of Philosophy, Stanford University, Chemical Engineering (2023)
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Master of Science, Stanford University, Chemical Engineering (2021)
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Bachelor of Science, Rice University, Chemical Engineering (2018)
All Publications
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Area-Selective Deposition by Cyclic Adsorption and Removal of 1-Nitropropane.
The journal of physical chemistry. A
2023
Abstract
The ever-greater complexity of modern electronic devices requires a larger chemical toolbox to support their fabrication. Here, we explore the use of 1-nitropropane as a small molecule inhibitor (SMI) for selective atomic layer deposition (ALD) on a combination of SiO2, Cu, CuOx, and Ru substrates. Results using water contact angle goniometry, Auger electron spectroscopy, and infrared spectroscopy show that 1-nitropropane selectively chemisorbs to form a high-quality inhibition layer on Cu and CuOx at an optimized temperature of 100 °C, but not on SiO2 and Ru. When tested against Al2O3 ALD, however, a single pulse of 1-nitropropane is insufficient to block deposition on the Cu surface. Thus, a new multistep process is developed for low-temperature Al2O3 ALD that cycles through exposures of 1-nitropropane, an aluminum metalorganic precursor, and coreactants H2O and O3, allowing the SMI to be sequentially reapplied and etched. Four different Al ALD precursors were investigated: trimethylaluminum (TMA), triethylaluminum (TEA), tris(dimethylamido)aluminum (TDMAA), and dimethylaluminum isopropoxide (DMAI). The resulting area-selective ALD process enables up to 50 cycles of Al2O3 ALD on Ru but not Cu, with 98.7% selectivity using TEA, and up to 70 cycles at 97.4% selectivity using DMAI. This work introduces a new class of SMI for selective ALD at lower temperatures, which could expand selective growth schemes to biological or organic substrates where temperature instability may be a concern.
View details for DOI 10.1021/acs.jpca.3c04339
View details for PubMedID 37683085
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Area-Selective Atomic Layer Deposition of Al2O3 with a Methanesulfonic Acid Inhibitor
CHEMISTRY OF MATERIALS
2023
View details for DOI 10.1021/acs.chemmater.3c00904
View details for Web of Science ID 001032143100001
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MYC oncogene elicits tumorigenesis associated with embryonic, ribosomal biogenesis, and tissue-lineage dedifferentiation gene expression changes.
Oncogene
2022
Abstract
MYC is a transcription factor frequently overexpressed in cancer. To determine how MYC drives the neoplastic phenotype, we performed transcriptomic analysis using a panel of MYC-driven autochthonous transgenic mouse models. We found that MYC elicited gene expression changes mostly in a tissue- and lineage-specific manner across B-cell lymphoma, T-cell acute lymphoblastic lymphoma, hepatocellular carcinoma, renal cell carcinoma, and lung adenocarcinoma. However, despite these gene expression changes being mostly tissue-specific, we uncovered a convergence on a common pattern of upregulation of embryonic stem cell gene programs and downregulation of tissue-of-origin gene programs across MYC-driven cancers. These changes are representative of lineage dedifferentiation, that may be facilitated by epigenetic alterations that occur during tumorigenesis. Moreover, while several cellular processes are represented among embryonic stem cell genes, ribosome biogenesis is most specifically associated with MYC expression in human primary cancers. Altogether, MYC's capability to drive tumorigenesis in diverse tissue types appears to be related to its ability to both drive a core signature of embryonic genes that includes ribosomal biogenesis genes as well as promote tissue and lineage specific dedifferentiation.
View details for DOI 10.1038/s41388-022-02458-9
View details for PubMedID 36207533
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Tuning Molecular Inhibitors and Aluminum Precursors for the AreaSelective Atomic Layer Deposition of Al2O3 br
CHEMISTRY OF MATERIALS
2022; 34 (10): 4646-4659
View details for DOI 10.1021/acs.chemmater.2c00513
View details for Web of Science ID 000805874800038
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Next generation nanopatterning using small molecule inhibitors for area-selective atomic layer deposition
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
2021; 39 (2)
View details for DOI 10.1116/6.0000840
View details for Web of Science ID 000631009400001
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Evaluation of solvents for in-situ asphaltene deposition remediation
FUEL
2019; 241: 1076-1084
View details for DOI 10.1016/j.fuel.2018.12.080
View details for Web of Science ID 000458760500108
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Assessment of the performance of asphaltene inhibitors using a multi-section packed bed column
FUEL
2019; 241: 247-254
View details for DOI 10.1016/j.fuel.2018.11.059
View details for Web of Science ID 000458760500024
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Investigation of Asphaltene Deposition at High Temperature and under Dynamic Conditions
ENERGY & FUELS
2018; 32 (12): 12405-12415
View details for DOI 10.1021/acs.energyfuels.8b03318
View details for Web of Science ID 000454567000037
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A Shipping Container-Based Sterile Processing Unit for Low Resources Settings
PLOS ONE
2016; 11 (3): e0149624
Abstract
Deficiencies in the sterile processing of medical instruments contribute to poor outcomes for patients, such as surgical site infections, longer hospital stays, and deaths. In low resources settings, such as some rural and semi-rural areas and secondary and tertiary cities of developing countries, deficiencies in sterile processing are accentuated due to the lack of access to sterilization equipment, improperly maintained and malfunctioning equipment, lack of power to operate equipment, poor protocols, and inadequate quality control over inventory. Inspired by our sterile processing fieldwork at a district hospital in Sierra Leone in 2013, we built an autonomous, shipping-container-based sterile processing unit to address these deficiencies. The sterile processing unit, dubbed "the sterile box," is a full suite capable of handling instruments from the moment they leave the operating room to the point they are sterile and ready to be reused for the next surgery. The sterile processing unit is self-sufficient in power and water and features an intake for contaminated instruments, decontamination, sterilization via non-electric steam sterilizers, and secure inventory storage. To validate efficacy, we ran tests of decontamination and sterilization performance. Results of 61 trials validate convincingly that our sterile processing unit achieves satisfactory outcomes for decontamination and sterilization and as such holds promise to support healthcare facilities in low resources settings.
View details for DOI 10.1371/journal.pone.0149624
View details for Web of Science ID 000372701200018
View details for PubMedID 27007568
View details for PubMedCentralID PMC4805258