Hi! I'm Dijana.

Experience

Graduate Research Assistant at Saint Mary's University

September 2013 - April 2016

Ab Initio investigation of aqualead (II) complexes as possible corrosion products in Super Critical Water Cooled Reactor (SCWR) One of the issues affecting SCWR development is the possibility of corrosion of construction material. The long term sustainability of SCWR largely depends on the ability to predict and control its water chemistry. Formation of corrosion products such as metal-ligand complexes is poorly understood both experimentally and computationally. Experimental research under extreme temperatures and pressures is difficult; computational method becomes a key research tool. A series of ab initio calculations of lead (II) complexes were performed.

SCWR utilizes supercritical water as a working fluid and operates at 650 °C and 25 MPa. Lead (Pb2+) is an impurity within the construction material of SCWR. Traces amount of lead are found to be major cause of the embrittlement. Traces of Pb2+ tend to dissolve from the construction material and form neutral complexes with surrounding anions (OH-, Cl-) and water and/or ammonia, resulting in corrosion.

The objective of this research was to perform a comprehensive ab initio calculations of lead (II) complexes including 4 different ligands: water, ammonia, hydroxide and chloride. Results include optimized geometries, vibrational frequencies and energetics of lead (II) complexes. Ultimately, results will contribute to development of an appropriate chemistry water control of SCWR.

Ab initio calculations were performed utilizing Gaussian03. The molecular geometries were fully optimized sequentially at HF (Hartree-Fock), MP2 (second-order Møller-Plesset perturbation theory) and B3LYP (Hybrid Density Functional Theory). Small atoms were studied using 6-31G*, 6-31+G* and 6-311+G* basis sets, while Pb was investigated using effective core potentials (CEP-121G, LANL2DZ and SDD). The best candidates for corrosion products were identified: [Pb(H2O)8]2+; Pb(OH)2 and PbCl2 and their hydration products.

Chemical Adviser and REACH
Registration Manager at PINUS TKI d.d.

April 2010 - August 2013

Chemical Adviser for agricultural pharmacudical company Pinus and biodiesel company BioGoriva, Slovenia. Designing labels with instructions for use for fito- pharmacudicals in accordance with DPD (1999/45/EC)/ DSD (67/548/EEC) directives, as well as CLP/GHS (2008/112/EC ). I was responsible for writing labels with instructions for following companies: Pinus Slovenia, Serbia Pinus Plus, Croatia Pinus Agro, Bosnia Pinus Pro, Macedonia, Kosovo, as well as collaboration with agricultural companies all over Europe including NuFARm Austria, DuPont France.

Preparation and revision of the Material Safety Sheets (MSDS) in accordance of CLP/GHS directive, as well as Regulation 790/2009, subsequently aproved by Ministry of Health of Slovenia. All MSDS created by me are available at PINUS internet site. Classifications of pesticides and biocides were subsequently forwarded to the Ministry of Agriculture for approval.

Managed registrations of chemicals under REACH Regulation (EC No 1907/2006) program in collaboration with Brussels ECHA. I wrote annual reports to the Ministry of Health of Slovenia, which included annual chemical inventory and sale reports.

My Chemical Advisor experties were under instructions from, the head of the Chemical Office of the Republic of Slovenia. Chemical Advisor experties encompased: Chemicals Act, Conditions for producing and trading in hazardous chemicals and the role and tasks of a chemical consultant, Storage of hazardous chemicals, REACH – general, registration and the chemical safety report, REACH – prohibitions and restrictions on use and placing on the market and authorisation, Classification, packaging and labelling of hazardous substances and preparations and safety data sheet, Reporting data on chemicals, Biocidal products, Persistent organic pollutants (POP’s), Prior informed consent procedure (PIC), Drug precursors, Goods of strategic significance for safety and health, Inspection.

Graduate Research Assistant at University of South Florida

August 2004 - December 2007

Research Titles: “Protein Folding/Unfolding of Poly-(Glu)20 utilizing Nd:YAG laser equipped Photoacoustic Calorimetry” and “Transient Optical and Potothermal Studies of CO binding to CT-cytochrome C at high pH”

Proteins have to be properly folded to their native conformation in order to obtain their biologically active form which allows them to perform specific functions within the body. Protein misfoldng has been implicated with a large number of devastating neurodegenerative diseases such as Alzheimer’s disease (AD), Amyotrophic Lateral Sclerosis (AS), cystic fibrosis and some forms of cancer.

Complete understanding of mechanisms through which proteins fold to their native structure opens the doors towards uncovering therapeutics that will help patients suffering from these diseases and will ultimately prevent development of neurodegenerative diseases. In order to map the mechanism through which proteins fold to their native conformation, photoacoustic calorimetry (PAC) coupled with fast phototriggering techniques (pH jump in case of Poly-(Glu)20 and CO photodissocitaion in case of CO-cytochrome c) was utilized to obtain time-resolved thermodynamics on fast time scale (~50ns- ~10µs) for Poly-(Glu)20 and CO bound native cytochrome c (CO Cyt c). Fast thermodynamics that were probed with PAC include magnitudes and life times of enthalpy (#H) and molar volume (#V) changes associated with coil-to-helix transition in case of Poly-(Glu)20 and unfolding-to-folding transition for CO-cytochrome c. Thus allowing for probing dynamics of folding and unfolding of small peptides on the time scale from ~50ns to ~10µs and identifying thermodynamic parameters that are missing pieces of the protein folding puzzle otherwise unattainable with the traditional calorimetric techniques due to their lifetime limitations.

The study was focused on probing folding/unfolding dynamics of small proteins thus avoiding complexity and heterogeneity associated with larger complexes.

Graduate Teaching Assistant at University of South Florida

August 2004 - December 2007

Graduate Teaching Assistant position at Department of Chemistry, University of South Florida, Tampa, Florida, USA.

• General Chemistry Discussion Class (Chemistry for Today) for science major students:
• Discussion Class Instructor: Dijana Lekic (me)
• General Chemistry Instructor: Dr. K. Caswell.
• General Chemistry Class Discussion (Chemistry for Today)
• For non-science students:
• Discussion Class Instructor: Dijana Lekic (me)
• General Chemistry Instructor: Dr. S. Grossman.
• Physical Chemistry laboratory:
• Instructor: Dr. Randy Larsen
• General Chemistry laboratory:
• Laboratory Instructor: Dijana Lekic (me)

• Duties as a Teaching Assistant:
• - Provided students with tutorials, clear objectives and expectations.
• - Taught and supervised students conducting
  chemistry experiments for duration of 3 hours laboratory period.
• - Actively provided advice to students performing labs.
• - Evaluated student performance while observing them conduct experiments.
• - Enforced safety rules and regulations in a laboratory.
• - Graded laboratory reports; recorded grades in an on-line grade book.
• - Gave feedback to the course instructor when requested.
• - Maintained clean laboratory environment.
• - Proctored midterm exams and final exams.

• Duties as a TA instructing Discussion Chemistry Class:
• • Taught 2 hours per discussion class per week.
• • Clearly communicated course material to students
  (provided students with examples regarding course lecture).
• • Actively involved students in discussion class, and encouraged them to use their critical thinking.
• • Administered quizzes and exams to students.
• • Graded quizzes and exams for all students.
• • Kept records of grades for all students and reported them in an on-line gradebook called the blackboard.
• • Gave feedback and assistance to the General Chemistry Professor as requested.