Chemistry Newsblog

Dr. Heather A. Rypkema

Department of Atmospheric, Oceanic, and Space Sciences

University of Michigan

November 14, 2014  

3:00 pm Chemical Sciences Building~ Room 101

Abstract:

Quantum chemical methods have a broad-ranging capacity toward informing our understanding of molecular transformations in a variety of environments, including the chemistry of the atmosphere. Specifically, these applications include kinetic and thermodynamic analysis of chemical reactions, evaluation of competing reaction channels, and the theoretical validation of postulated chemical mechanisms. This presentation provides a survey quantum chemistry as applied to a number of atmospherically relevant studies. The full atmospheric oxidation profile of peroxyacetic acid predicts the likely fate of a prevalent atmospheric species while postulating a new source of reactive species not represented in current models. The direct and catalyzed hydration of formic acid and acetaldehyde provide a mechanism for the formation of hygroscopic molecules capable of initiating cloud formation and the production of SOA. Diabatic excited states can be used to predict the relative reactivity among atom-transfer reactions, which are particularly significant in a hydroxyl-rich environment. A mechanism for the proliferation of atmospheric hydroxyl radical through the atmospheric oxidation of cyclical alkanes provides a possible explanation for the discrepancy between predicted and measured OH levels in the troposphere. Cumulatively, these studies will demonstrate the diverse applications of theoretical quantum chemistry in enhancing our understanding of atmospheric chemistry.

Dr. Ashutosh Tiwari, Assistant Professor of Chemistry

Department of Chemistry,  Michigan Technological University     

November 7, 2014  ~  3:00pm  ~  Chemical Science Building, Room 101

Abstract:

Due to the aging of baby boomers in the USA, the proportion of the population in higher age groups has increased. This demographic shift coupled with a concomitant increase in longevity has brought new challenges and threats in the form of diseases and disorders that not only affect an individual but impact the whole society at large. Increased oxidative damage of proteins associated with aging causes them to misfold and aggregate and thus, disorders related to protein misfolding and aggregation are on the rise. Since many aggregated proteins share a common fibrillar structure at the molecular level, understanding the principles and contributing factors that regulate protein misfolding, surface hydrophobic exposure, aberrant interactions, or aggregation is key to understanding their relationship to cellular toxicity. I will discuss recent results from my laboratory wherein we studied several proteins for their surface-hydrophobic exposure and aggregation propensity at physiological pH and temperature. Identifying shared protein aggregation pathways for a large set of structurally diverse proteins will lead to a better understanding of the disease process and as a consequence provide common effective targets for therapy.

Mark R. Mason

Professor, Department of Chemistry and Biochemistry and
Director,  School of Green Chemistry and Engineering
The University of Toledo
Thursday, November 6, 2014
11:00 am Chemical Sciences Building Room 102

Over the past two decades, there has been a dramatic shift in the way government and industry view pollution prevention and the environmental consequences of chemical manufacture in the United States. Source reduction, rather than “end of the pipe” waste treatment, is now the preferred method for reducing pollution. This approach requires chemists and engineers to be increasingly aware of the environmental consequences of the chemical-related products and processes we develop. Green chemistry, “the design of chemical products and processes that reduce or eliminate the use and generation of hazardous substances,” is the foundation of this increased awareness. This presentation will provide an overview of selected green chemistry principles, green chemistry applications and metrics, chemical alternatives assessment, and future opportunities.

Prof. Scott K. Silverman,   Professor of Chemistry

Department of Chemistry, University of Illinois at Urbana-Champaign

October 10, 2014  ~  3:00pm  ~    Chemical Science Building, Room 101

Abstract:

DNA in its double-stranded form is familiar as the genetic material. When single-stranded, however, DNA can adopt complex three-dimensional structures that allow binding of substrates and catalysis of chemical reactions. DNA has many conceptual and practical advantages over other biologically derived polymers (proteins and RNA) for applications as a catalyst.  This presentation describes the development of DNA catalysts, or deoxyribozymes, for a variety of chemical reactions, primarily involving covalent modification of peptide and protein substrates.

John A. Jaszczak
Department of Physics and the A. E. Seaman Mineral Museum Michigan Technological University

 December 5,  2014, 3:00pm Chemical Science Building, Room 101

Abstract:

The Lelatema Mountains in northern Tanzania are host to one of the world’s richest flake graphite deposits, but it is the purple-blue gem variety of zoisite called “tanzanite” that has brought renown to the region since the 1960s.

In December 2007 a pocket of exceptionally fine crystals of graphite was discovered at in Merelani’s Block D. Given graphite’s extreme softness and obvious lack of gem value, it seems almost in miraculous that specimens of these graphite crystals, perhaps the finest in the world, were superbly preserved. Adding to their uniqueness and beauty, the graphite crystals are covered by a secondary overgrowth of graphite that contains rare stellate graphite dendrites. The pocket also produced superb gem-quality crystals of diopside, fluorapatite, and tremolite crystals. More recently, world-class specimens of several sulfide minerals have been discovered and preserved. These include highly lustrous, large Pyrite crystals, exceptionally large, translucent crystals of the rare ZnS polytype wurtzite, and rare black octahedral crystals of alabandite. This illustrated lecture will briefly tour this amazing mining district, review these seemingly miraculous mineralogical that have been uncovered.

Dr. Emanuele Petruzzella
epetruzz@emich.edu
Postdoctoral Researcher Scholar, Chemistry Department, Eastern Michigan University 09/26/2014 – 3:00 pm – Room 101, Chemical Sciences and Engineering Bldg

Abstract:

The antitumor activity of kiteplatin was reported for the first time twenty years ago. Recently, kiteplatin was investigated as potential antitumor drugs for the treatment of cisplatin- and oxaliplatin-resistant tumors.

Resistance to Pt-based antitumor drugs can involve different processes, such as the binding of S-donor biomolecules, like glutathione, cysteine and methionine, to the Pt metal center. This interaction prevents Pt drugs to react with DNA, i.e. the event triggering the antitumor effect. Kiteplatin showed an unique reactivity with these S-donors biomolecules and, for the first time, it was found that, also after reaction with glutathione, kiteplatin is still able to react with a DNA model. This unique behaviour could explain the activity of kiteplatin in cisplatin- and oxaliplatin-resistant tumors.

In recent years, several research groups investigated Pt(IV) derivatives of Pt-based anticancer drugs as pro-drugs for oral administration. The axial dihydroxido Pt(IV) derivative of kiteplatin undergoes a spontaneous thermal- and/or photoinduced reduction process. This Pt(IV) complex can be suitable for photo-therapy.