Abstract: Understanding materials at their atomic level is important given that the macroscopic properties of a material are intricately linked to its nanoscale structure. This plays a pivotal role in advancing structural materials since their performance is significantly influenced by factors such as composition, and microstructure which consist of different interfaces, crystalline phases, and defects. 

In the automotive and aerospace industries reducing the weight of materials is critical to enhance fuel efficiency without compromising safety and performance. Lightweight aluminum alloys are extensively studied to replace heavier materials in these sectors. This work offers a comprehensive characterization of the evolution of various precipitates within aluminum alloys under laser treatment conditions, aiming to enhance their mechanical properties.

The thesis also delves into understanding the diffusion and dissolution mechanisms of metal nanoparticles on or into metal oxides. Metals like gold, in their bulk form, are traditionally considered chemically inert and inefficient as catalysts. At the nanoscale, however, as the particle size decreases, their catalytic activity towards various reactions significantly increases. Our exploration of these systems under in situ TEM heating has provided valuable insights into the structure-function relationships of these interfaces. This knowledge can be employed in optimizing the production of nanomaterials with enhanced interface properties.

KEYWORDS: Aluminum alloys, precipitate hardening alloys, SLV, TEM, in situ TEM

Abstract: The living cell is an intricate and synchronized organization with compartmentalization across diverse length scales. While intracellular compartments such as the lysosome and mitochondria are bound by membranes, cells also contain organelles, not confined by membranes, known as “biomolecular condensates”. Recent studies showed that many biomolecular condensates are viscoelastic materials formed from the phase separation of proteins and nucleic acids. The abrupt changes in composition and material properties of these condensates impair their biological function and are often associated with cancer, ribosomopathies, and aging disorders. Therefore, synthetic systems are required to create model biomolecular condensates in living systems. These systems aim to elucidate the biophysical principles of intracellular organization and diseases. In the first part of my talk, I will discuss our work on using protein oligomerization and sequence interactions in vivo to create multiphasic biomolecular condensates that mimic native condensate assemblies. We show that specific molecular and nanoscopic design principles can be exploited to design optogenetic fusion proteins that exhibit targeted condensation with high spatiotemporal resolution. Later in this talk, I will describe our work on synthetic polymers to form condensates that mimic the function of underwater adhesive proteins secreted by marine organisms such as mussels and sandcastle worms. In summary, the bioinspired design of macromolecules that form model biomolecular condensates represents new frontiers to ask fundamental questions on the behavior of mesoscopic biological assemblies in living cells and to inspire the design of novel functional materials.

Abstract: Fossil fuels have been overwhelmingly used in many industry sectors in past decades, suffering from significant CO₂ and other pollutant emissions, low efficiency, and nonsustainability. Clean and efficient energy storage and conversion via electrochemical reactions associated with hydrogen, oxygen, and water have attracted substantial attention for energy and environmental sustainability. Among compelling energy technologies, hydrogen proton exchange membrane fuel cells (PEMFCs) are a promising zero-emission power source for transportation to mitigate environmental pollution and reduce fossil-fuel dependence. Meanwhile, water electrolyzers have been clearly identified as the sustainable pathway to produce cheap green hydrogen efficiently using renewable electricity. However, current materials, including catalysts, membranes, and ionomers, cannot meet the challenging targets of high-efficiency, low-cost, and long-term durability of hydrogen fuel cells and water electrolyzers. Developing high-performance catalysts from earth-abundant elements to replace current precious metals is crucial for making these hydrogen technologies viable for large-scale clean energy applications. U.S. DOE has been continuously supporting his research group at SUNY-Buffalo in the past decade, aiming to address materials issues by designing and scaling up innovative and highly efficient catalysts and electrodes. This talk discusses recent understanding, progress, achievement, and perspective on developing low-cost and high-performance catalysts based on newly emerging atomically dispersed metal-nitrogen-carbon materials for sustainable and clean hydrogen technologies.

Gang Wu is a professor in the Department of Chemical and Biological Engineering at the University at Buffalo (UB), The State University of New York (SUNY-Buffalo). He completed his Ph.D. studies at the Harbin Institute of Technology in 2004, followed by extensive postdoctoral training at Tsinghua University (2004-2006), the University of South Carolina (2006-2008), and Los Alamos National Laboratory (LANL) (2008-2010). Then, he was promoted to a staff scientist at LANL. He joined SUNY-Buffalo as a tenure-track assistant professor in 2014 and was quickly promoted to a tenured associate professor in 2018 and a full professor in 2020. His research focuses on functional materials and catalysts for electrochemical energy technologies. He has published more than 320 papers in prestigious journals, including Science, Nature Energy, Nature Catalysis, JACS, Angew Chem, and Advanced Materials. His papers have been cited more than > 48,000 times with an H-index of 118 (Google Scholar) by November 2023. He is currently leading and participating in multiple fuel cell, battery, and renewable fuel (e.g., NH₃) related projects with a total research funding of more than $10.0 M. Dr. Wu was continuously acknowledged by Clarivate Analytics as one of the Highly Cited Researchers since 2018. He recently received the SUNY Chancellor’s Award for Excellence in Scholarship & Creative Activities (2021) and UB’s Exceptional Scholar–Sustained Achievement Award (2020). He serves as Associate Editor for a few journals, including the Journal of the Electrochemical Society (JES), the Electrochemical Society’s flagship journal.

Event Info: We will discuss what our program structure, what we do, and how the state program compliments and supports federal CERCLA mandates. We intend on highlighting examples of current site-work and how chemistry is integral to the field of environmental protection, as well as playing a part in protective and sustainable community redevelopment.

Bio: Sheri is a Registered Professional Geologist with over 24 years of experience in the environmental field, specifically in contaminated site characterization & remediation, regulation development, and beneficial reuse. After a brief stint performing geotechnical work in private consulting Sheri started with KDEP in 2000 as a Geologist with the tanks program, becoming a supervisor in the Superfund Branch in 2007.  Between 2007 and 2012, Sheri supervised the State Superfund Section, then the Federal Superfund Section before accepting the branch Environmental Scientist Consultant position.  As an E.S. Consultant, she focuses on scientific research, and regulation & policy development for Kentucky’s Superfund, Brownfields, and other programs.  In addition, Sheri serves as the technical lead for Kentucky's high priority clean-up sites. Outside of her career with the commonwealth of Kentucky, Sheri is on the Board of Advisors to the Kentucky Geological Survey and a long-time active member of the Association of State and Territorial Solid Waste Management Officials. In her free time, she enjoys traveling, hiking, cycling, reading, fiber arts, and creating stained glass. 

ABSTRACT

Ambient ionization mass spectrometry (AIMS) is an evolving soft ionization technique that directly snapshots biomolecular profiles, spatial distributions, and chemical changes from biological tissue or fluids with minimal pretreatment. I will first introduce the methodology development of two representative AIMS techniques, namely air-flow-assisted desorption electrospray ionization mass spectrometry imaging (AFADESI-MSI) and conductive polymer spray ionization (CPSI), along with their applications in preclinical anti-tumor drug research and clinical cancer diagnosis. The topic will be then shifted to using AIMS to create water microdroplets, which exhibit ultrafast kinetic and favorable thermodynamic microenvironment differing from equal volume of bulk solution phase. I will introduce my research on AIMS-based microdroplet chemistry for both bioanalysis and synthesis of basic building blocks of life materials.

Adoption of the correct three dimensional structures by biomolecular complexes in solution is essential for their performance in cells, and the formation of individual non-covalent interactions can be critical to their stability and functions. There is thus much interest in developing solution-state methods of detection to determine the arrangement of atoms at particular locations in these complexes, and that are sensitive to the stabilities of the local structural motifs they form. The Stelling group develops the vibrational states of nucleic acids and an essential substrate for a broad range of enzymatic reactions, s-adenosyl-l-methionine (AdoMet), as solution state sensors of local structure and energetics when they are contained within the large number of complexes that bind them in cells. Over the short term, the dimensions of specific vibrational states of the nucleic acids and AdoMet will be determined via rigorous isotope labeling and computational studies. Over the long term, these submolecular-scale sensors will be deployed to examine local structure and dynamics in the active sites of the vast number of enzymes that use AdoMet as a substrate, and to probe nucelobase structure and stability in DNA and RNA containing nuceloprotein complexes.

Abstract

The accurate identification and detailed analysis of biomolecules have led to a deeper understanding of biological intricacies, paving the way for innovative therapeutic strategies. The cutting-edge field of single-molecule techniques has emerged as a highly promising avenue in this pursuit of revealing the identity and real-time dynamics of biomolecular structure and interactions. In this seminar, I will discuss the development of single-molecule bioanalytical approaches, from unraveling the stability and dynamics of folded nucleic acid structures to proteomics applications. By employing DNA nanotechnology techniques to create a confined space for a G-quadruplex (GQ) structure and performing single-molecule mechanical unfolding assay of GQ using optical tweezers, we revealed that confined space facilitates the folding of the G-quadruplex  structure by enhancing both stability and kinetics. Venturing into single-molecule proteomics, we introduced the mechanically reconfigurable DNA Nanoswitch Calipers (DNC) capable of measuring multiple coordinates on single biomolecules with angstrom-level precision. By measuring the distances of specific amino acid residues in optical and multiplexed magnetic tweezers, our work extends to the single molecule fingerprinting of peptides, showcasing discrimination within a heterogeneous population and even between distinct post-translational modifications. Furthermore, by using force-activated barcodes in measuring the distances of biotin-binding sites in single native-folded biotin-streptavidin complexes, we demonstrated the DNC’s potential in single-molecule structural proteomics applications.

Climate change due to greenhouse gas build up in the earth’s atmosphere is an existential threat to humanity. To mitigate climate change, a significant shift from fossil fuels is necessary. Over the years, several renewable energy sources like solar, wind, geothermal etc. have been explored with emphasis on discovering and developing new materials with better performance. In this work, we focus on using first principles computational methods to investigate key functional properties of materials of interest for applications in solar cells and catalytic conversion for energy generation. We show geometric effects of carboxylic acid binding on a transition metal surface to impact the deoxygenation reaction mechanism. Using insights from binding energy calculations and transition state theory, we elucidate the reaction pathway. From geometric study of surface substituted with organic ligands on the perovskite surface, we show the effect of fluorination of the phenyl ring of anilinium on the relative surface energy, relative binding energy, surface penetration, work function and surface electronic properties. Lastly, through first principles, we discover the geometric unfolding of the perylene diimide (PDI) chromophore due to change in the overall charge on the organometallic complex. With further investigation from time-dependent density functional theory, we discover the electron reservoir behavior of the PDI chromophore which is responsible for CO₂ reduction.

KEYWORDS: Density Functional Theory, Catalysis, Green Energy Generation, Surface Binding, Reaction Mechanisms, Electron Reservoir

Graduate Student Profile

Abstract: 1,2-diamine substructures are prevalent functional motifs found in natural products, pharmaceutical compounds, and ligands. The interesting utilities of 1,2-diamines have inspired many synthetic chemists to design various methodologies for the preparation of these structures from simple precursors such as alkenes. Despite the well-established analogous dihydroxylation or aminohydroxylation of alkenes, the introduction of two amino groups across the double bond has been more challenging to accomplish. In this work, we described two different, but related methods using simple and easily accessible reagents for 1,2-diamination of alkenes. In the first method, an alkene undergoes 1,3-dipolar cycloaddition with an organic azide to form a 1,2,3-triazoline. Subsequent N-alkylation of the generated 1,2,3-triazoline gives the 1,2,3-triazolinium ion, which was then hydrogenated over Raney Ni with a balloon of H2 to produce 1,2-dimine. Traditionally, it has been believed that a 1,2,3-triazoline is an unstable species in the presence of heat or light and will readily extrude N2 to form an imine or an aziridine.  However, most of the 1,2,3-triazolines prepared in this work were stable to the extrusion of N2 at the temperature required for their formation. In the second method, the alkene undergoes 1,3-dipolar cycloaddition with a 1,3-diaza-2-azoniaallene (azidium ion) to afford a 1,2,3-triazolinium ion directly. The 1,2,3-triazolinium ions are reduced to the corresponding 1,2-diamines using the same conditions described above. X-ray crystallographic analysis and 1D/2D NMR spectra confirmed the stereochemistry of the synthesized 1,2,3-triazolinium ions and 1,2-diamines.

Ankit Pandeya

Graduate Student Profile

Abstract:

Antibiotic resistance is one of the major global issues in the field of public health and medicine. Good antibiotic candidates need to be selectively toxic, inhibit cellular target, and effectively penetrate and accumulate in bacterial cells. The last factor is a formidable barrier in the development of antimicrobials effective in Gram-negative bacteria, due to the presence of two layers of cell envelope. The first half of my thesis focuses on understanding the permeation of small molecules through this formidable cell envelope, distribution inside the cell of Gram-negative bacteria, and design of novel methods to make small molecules effectively cross the cell envelope. The second half of my thesis focuses more on the crosstalk between Gram-negative bacteria and host immune system during systemic infection and sepsis. More specifically we studied the contribution of inflammasome activation and pyroptosis during pathogenesis of Salmonella systemic infection.  

In the first project, I studied the accumulation and distribution behavior of fluoroquinolone class of antibiotics inside Gram-negative bacteria using E. coli as a model. Although several studies have been focused regarding the correlation between compound’s cellular accumulation and their effectiveness against Gram-negative bacteria but no correlation between accumulation of antibiotics and their efficacy has been observed. In this study, we measured the concentration of nine fluoroquinolones accumulated in the subcellular compartments of E. coli. Good correlation between the MIC and the cytoplasmic accumulation, but not whole cell accumulation, was observed using a pair of isogenic wild type and drug-efflux deficient strains. Our results supported the explanation that the efficacy cannot be determined by the whole cell accumulation alone. Accumulation in the target region as well as the intrinsic potency determines the effectiveness of an antimicrobial compound.

In the second project, I explored whether conjugation of biotin to small molecules can increase the permeation of small molecules through the Gram-negative cell envelope. We used a florescent molecule pair, Atto565 and Atto565-biotin as model compounds and studied their permeation behavior in E. coli. Our results indicated that biotinylation helped the molecule Atto565 to cross the outer membrane of E. coli through OmpC porin.

Moreover, in the third project, I studied how the inflammasome activation and pyroptosis plays a role in pathogenesis of Salmonella systemic infection. We found that Salmonella systemic infection causes severe inflammation as indicated by very high plasma concentration of pro-inflammatory cytokines, IL-1β, IL-6 and TNF-α. Furthermore, it also caused disseminated intravascular coagulation (DIC) as indicated by increased prothrombin (PT) time and plasma thrombin-antithrombin (TAT) levels. Deficiency of caspase 1 protected the mice from Salmonella induced inflammation, coagulation and death during acute systemic infection. Similarly, deficiency of NAIP and GSDMD significantly reduced the Salmonella induced inflammation in vivo. In addition to this, in vitro studies showed that deficiency of Caspase 1, NAIP and GSDMD also protects the bone marrow derived macrophage’s (BMDM’s) death upon Salmonella infection. Use of flagellin and Salmonella pathogenicity island 1 (SPI1) region knockout strains of Salmonella induced significantly less cytokine release in the plasma, however, could not protect from the coagulation and lethality. In vitro, inflammasome activation and BMDM death was also completely abolished when flagellin or SPI1 deficient strains of Salmonella were used. These results indicate that during acute Salmonella systemic infection severe inflammation occurs mainly through NAIP/Caspase 1/GSDMD axis induced by the combination of both flagellin and T3SS. However, coagulation could also be induced also by factors other than flagellin and T3SS present in SPI1 that contributes to lethality.