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2017 Seminars

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Spring 2017 Seminars

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Friday, January 20, 2017

3:30 p.m.
Bertrand H. Snell Hall Room 212

Dr. Brian Panama

Masonic Medical Research Laboratory

Utica, NY

will speak on

Atrial electrophysiological and molecular remodeling induced by obstructive sleep apnea"

Abstract:

Background: Obstructive sleep apnea (OSA) affects 9-24% of the adult population. OSA is associated with atrial disease, including atrial enlargement, fibrosis and arrhythmias. Despite the link between OSA and cardiac disease, the molecular changes in the heart which occur with OSA remain elusive. To study OSA-induced cardiac changes, we utilized a recently developed rat model which closely recapitulates the characteristics of OSA.

Methods and Results: Male Sprague Dawley rats, aged 50-70 days, received surgically implanted tracheal balloons which were inflated to cause transient airway obstructions. Rats were given 60 apneas per hour of either 13 seconds (moderate apnea) or 23 seconds (severe apnea), eight hours per day for two weeks. Controls received implants, but no inflations were made. Pulse oximetry measurements were taken at regular intervals, and post apnea ECGs were recorded. Rats had longer P wave durations and increased T wave amplitudes following chronic OSA. Proteomic analysis of the atrial tissue homogenates revealed that three of the nine enzymes in glycolysis, and two proteins related to oxidative phosphorylation, were down‑regulated in the severe apnea group. Several sarcomeric and pro-hypertrophic proteins were also up-regulated with OSA.

Conclusion: Chronic OSA causes proteins changes in the atria which suggest impairment of energy metabolism and enhancement of hypertrophy.

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Friday, January 16, 2017

9:00 a.m.
Science Center Room 244

Wen An

M.S. Defense

M.S Candidate

Clarkson University

will speak on

“Zwitterionic Metal-Organic Frameworks: Rational Design and Fundamental Research"

Abstract:

The work presented in this thesis demonstrates the research perspective that specific adsorption properties of Metal-Organic Frameworks (MOFs) can be accessed by introducing intramolecular electrostatic fields through zwitterionic (ZW) ligands. The two components of this work include an in-depth investigation of the synthesis, characterizations and real world applications of MOFs followed by specific examples of new ZW MOFs that have been synthesized and characterized in my research projects. The single crystal structures, thermal stabilities and the gas adsorption analyses of these new ZW MOFs will be discussed in detail.
MOFs are a new class of crystalline porous materials composed of metal clusters connected by polytopic organic linkers. They have large open voids and high surface areas, which surpass traditional porous materials. The framework structures, pore environments and functionalities can be tailored to specific needs by modifying the combination of metal clusters and organic ligands. The highly tunable nature and versatility of MOFs allow them to function as advanced porous materials capable of applications such as gas storage and small-molecule separations.
Since MOFs are self-assembled from organic ligands and metal nodes through traditional coordination bonds, the structural geometries of these materials can be designed to satisfy certain requirements. The metal ions have fixed coordination geometries when linked to organic ligands, and the rigid or flexible nature of the bridging ligands will result in distinct chemical environments. My investigations commence with the structural design of novel ZW ligands with the objective to synthesize advanced ZW MOFs. ZW ligands consist a unique combination of cationic (e.g., pyridinium N atom) and anionic functional groups (e.g., a carboxylate anion). These well separated positive and negative charges form an electrostatic field gradient along the zwitterion’s molecular surface, creating a charged organic surface within the pore environment.  This effect may result in the polarization of guest molecules which has the potential to increase host-guest interactions and thus, enhancing the MOF’s adsorption enthalpies. 
Herein, I report the design of three unique pyridinium-based ZW ligands 1,1′,1′′-(benzene-1,3,5-triyl)tris(methylene)tris(4-carboxypyridinium) tribromide (H3L1Br3), 1,1′-(benzene-1,4,-diyl)di(methylene)di(4-carboxypyridinium) dibromide (H2L2Br2)  and 3-carboxy-1-(3-carboxybenzyl)pyridinium bromide (H2L3Br). The nitrogen functionalities of the pyridinium derivatives are of cationic nature while being charge compensated by bromide anions. Upon deprotonation of the carboxylic acid sites and incorporation of the ZW ligand into a MOF, four new ZW MOFs were synthesized and characterized by single-crystal X-ray diffraction (SCXRD), infrared spectroscopy (IR), elemental analyses, powder X-ray diffraction (PXRD), thermogravimetric analyses (TGA), differential scanning calorimetry (DSC) and adsorption analysis. Gas adsorption measurements of these new ZW MOFs yielded promising results revealing that strongly charged functional groups in the framework promote charge-quadrupole interactions with gas molecules, hence increasing the gas uptake. Particularly, the MOF {[CdBr(L)]·(ClO4)·2DMF}n exhibits an unprecedented light-responsive adsorption effect attributed to the reversible photoinduced generation of radicals to produce a switchable electrostatic pore surface.

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Friday, January 13, 2017

3:30 p.m.
Bertrand H. Snell Hall Room 212

Dawei Xu

Clarkson University

will speak on

Development of Supramolecular Filamentous Cell Penetrating Peptide for Therapeutic Delivery"

Abstract:

The discovery of Cell Penetrating Peptides (CPPs) has great impacts on both fundamental and translational biomedical research due to their unique ability to transverse cell membranes. Natural CPPs are typically in their monomeric state, which has poor stability for in vivo circulation. In this seminar, I will discuss our recent development of Filamentous Cell Penetrating Peptide (FCPPs) that possess greatly improved stability against proteolysis, and exceptional ability to perturb cell membrane with minimal cytotoxicity. We believe the acquired knowledge through these studies of FCPPs could potentially be established as a new and unique CPP platform with well-defined filamentous structure and ease of incorporating multi-therapeutics to treat various human diseases ranging from anti-viral infection to cancer therapy.  

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Friday, January 13, 2017

8:30 a.m.
Bertrand H. Snell Hall Room 212

Anahita Karimi

PhD Defense

PhD Candidate

Clarkson University

will speak on

Electroanalytical Evaluation of Nanoparticles by Nano-impact Electrochemistry"

Abstract:

Applications of engineered nanoparticles in electronics, catalysis, solid oxide fuel cells, medicine and sensing continue to increase. Traditionally, nanoparticle systems are characterized by spectroscopic and microscopic techniques. These methods are cumbersome and expensive, which limit their routine use for screening purposes. Electrochemistry is a powerful, yet underutilized tool, for the detection and classification of nanoparticles. The first part of this presentation will discuss the potential of this technique for investigating bioconjugation and biomolecular recognition. Fundamental study of biorecognition is important for the development of therapeutics and molecular diagnosis probes in the biomedical, biosensing and biotechnology fields. A study of molecular binding mechanisms of ssDNA at single particle surfaces and target detection at aptamer functionalized nanoparticles will be provided. The second part will describe the use of this method as a screening tool of particle reactivity. We study the interaction and adsorption of a toxic environmental metalloid (arsenic) with metal oxide nanoparticles to extract mechanistic, speciation and loading information. We discuss the potential of this approach to complement or replace costly characterization techniques and enable routine study of nanoparticles and their reactivity. 

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