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2017 Seminars

In this Section

Summer 2017 Seminars

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Thursday, May 25, 2017

10:00 a.m.
Petersen Board Room (Snell Room 330)

M.S. Defense

Linhai Jiang, Graduate Student

Clarkson University

will speak on

“Discrete Nanostructured Protein Mimics From Symmetry Directed Self-assembly of De novo Designed Chimeric Peptides"

Abstract:

Well-defined artificial protein nanomaterials are mostly achieved by the self-assembly of rationally designed recombinant proteins where multiple protein folding domains interact with each other in a highlyregulated pattern. Using synthetic molecules as the molecular building blocks will allow fabrication of artificial proteins with greater chemical versatility and structural tunability to suit various needs in nanotechnology and biotechnology. However, the success is quite limited due to the lack of precise control over geometric packing and intermolecular interactions among the synthetic building blocks.

A two-component synthetic peptide-based material platform for the construction of well-ordered discrete globular protein mimics will be illustrated in this presentation. These peptides are designed to mimic fusion proteins where two orthogonal protein folding motifs in different folding symmetry are involved, one being collagen triple helices and the other being coiled coil dimer. Using this method, we demonstrated the formation of nanostructures in two distinct symmetric architecture, i.e. a 12-subunit tetrahedron-like dodecamer under salt-containing condition and a 6-subunit trigonal bipyrimidal-like hexamer under salt-free condition. This initial successful design approach will lead to a wide array of protein mimics with tunable size, shape, surface chemistry and dynamic stability to suit various needs in synthetic biology, biotechnology and nanotechnology. The results are of great interests to general audiences in both science and engineering to assemble discrete protein-like nanomaterials and use them to probe various complex biological processes.

Fig. 1

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Spring 2017 Seminars

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Friday, April 28, 2017

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

Professor Richard M. Crooks

Department of Chemistry

The University of Texas at Austin

will speak on

“Development of Electrocatalytic Models for Testing Theory"

Abstract:

One approach for designing improved nanoparticle catalysts involves the use of first-principles calculations, such as density functional theory (DFT), to predict the structural properties of efficient, new materials. As these types of calculations have begun to emerge, however, it has become increasingly clear that there are few really good experimental models available to test their predictions. Dendrimer-encapsulated nanoparticles (DENs) provide an opportunity to meet this need, because their size, composition, and structure can be controlled and because they have a size that is compatible with DFT calculations (< 300 atoms).  DENs are synthesized by complexing metal ions with interior tertiary amines of poly(amido amine) (PAMAM) dendrimers, followed by chemical reduction.  In this talk, I will discuss the basic approach for synthesizing DENs, provide two examples of the interplay of theory and experiment that leads to a better understanding of electrocatalysis, and then discuss some very recent unpublished work focused on more complex (and hence more realistic) electrocatalytic structures comprised of DENs and metal oxide surfaces.

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Friday, April 28, 2017

9:00 a.m.
CAMP Room 372

Ph.D. Defense

Darpandeep Aulakh, Ph.D. Candidate

Clarkson University

will speak on

“Metal-Organic Frameworks as Versatile Storage and Separation Platforms"

Abstract:

Since the end of the 20th century, the synthesis, characterization, and functionality of metal-organic frameworks (MOFs) has become a widely researched area of study. These frameworks are crystalline porous materials built from metal clusters connected by polytypic organic linkers. An important feature is that their framework structures, pore environments, and functionalities can be controlled by the choice of metal and organic building blocks. Their primary physical properties, namely, their large accessible voids and high surface areas, offer potential applications in gas and small molecule storage. The possibility of functionalizing their pore environments as well as tuning their topologies and pore sizes allows for their use in other diverse applications, such as chemical separation and catalysis. Most MOFs reported to date, however, are microporous (pore sizes <2 nm), and only a small fraction have ordered mesoscale domains (2-50 nm). These mesoporous materials are attracting intense interest because their well-ordered cavities are excellent hosts for achieving precise long-range assembly of larger guest molecules (e.g. proteins and drugs) and for the fabrication of functional hybrid materials.  For example, they are excellent candidates for composite and device fabrications and as containers for nanoparticles, thus constituting a physical bridge between the nanoscopic and macroscopic worlds.  In this work, the fundamental understanding in the exciting structure-property relationships of new micro- and mesoporous MOFs and their potential applications in our energy landscape, including gas storage, separation, and data storage will be focused.

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Friday, April 21, 2017

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

Dr. Carlos D. Garcia

Department of Chemistry

Clarkson University

will speak on

“MICRO/NANO… DOES IT MAKE A DIFFERENCE?"

Abstract:

The field of miniaturization in chemical analysis has seen tremendous growth in the last few decades enabling the collection, pretreatment, separation, and detection of minute amounts of materials with minimal human intervention. Despite these advances, a key shortcoming of miniaturization is the lack of integration of many analytical steps into a single device. Aiming to address this gap in current technology, part of our group is focused on the development of simple strategies leading to the development of low-cost microfluidic devices. As examples of the outcomes of these projects, the development of devices using CO2 laser engraving from plastic, paper, and glass will be discussed. In addition, the seminar will describe recent results obtained with carbon electrodes developed by pyrolysis of paper substrates and the development of a robotic platform to perform remotely-controlled analyses. The presentation will also address the outcomes of a project focused on the adsorption of proteins to nanostructured surfaces. The hypothesis is that a detailed understanding of the interaction process will lead to rational methodologies to fabricate biosensors with improved performance. In this regard, examples of the interaction of enzymes with carbon nanotubes will be complemented with results related to the characterization and potential biomedical uses of optically transparent carbon electrodes.

Fig 1 Fig 2 Fig 3

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Friday, April 21, 2017

9:00 a.m.
Snell Hall Room 330

Ph.D. Defense

Jennifer A. Ritz, Ph.D. Candidate

Clarkson University

will present

“On the Various Roles of Tetraoctylammonium-Metal Complexes in the Synthesis and Chemistry of Organosoluble Metallic Nanoparticles"

Abstract:

In this work, studies into the generation of tetraoctylammonium-metal complexes, and the various roles of these complexes in the synthesis and chemistry of organosoluble metallic nanoparticles, are presented. Tetraoctylammonium-metal complexes may serve in these reactions as phase-transfer products, one-phase metathesis products, metallic nanoparticle precursors, oxidants, and oxidation products. The phase-transfer synthesis of tetraoctylammonium complexes of Pd(II), Pt(II), Pd(IV), and Pt(IV) is thoroughly studied. A new, single-phase method has been developed for the synthesis of tetraoctylammonium complexes of metal-halide anions of Au(III), Ag(I), Pd(II), and Pt(II), which avoids the problems of phase-transfer methods and yields reproducible products. The valuable organosoluble reductant tetraoctylammonium borohydride is generated through a phase transfer reaction. All tetraoctylammonium complexes were synthesized, purified, and characterized, and were stable in dry storage. The tetraoctylammonium-metal complexes generated through single-phase metathesis and tetraoctylammonium borohydride are applied to the synthesis of monometallic and bimetallic alkanethiolate-protected nanoparticles through a novel, single-step, single-phase method in toluene. Finally, the oxidation of Pd(0) by tetraoctylammonium-Pd(IV) complexes, which proceeds via a comproportionation mechanism to produce tetraoctylammonium-Pd(II) complexes, is demonstrated.

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Friday, April 14, 2017

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

Darpandeep Aulakh, Ph.D. Candidate

Clarkson University

will speak on

“Novel Magnetic Composite Materials- Metal Organic Frameworks as Hosts for Molecular Magnets"

Abstract:

Next-generation computer technologies will require ultrahigh-density data storage devices and quantum computing based on isolated spin-carriers, so-called molecular spintronics. Single-molecule magnets (SMMs) have shown great potential for such applications. Their unique magnetic properties enable SMMs to be used in spintronics for switching from total spin up to total spin down on a molecular level, and therefore each molecule can be used as a magnetic bit of information. Although a broad community works on the design of new SMMs with improved properties, coupling of the nanoscale units to the macroscopic world remains as a key challenge. Any practical application of SMMs requires in the first step their organization in 2D or 3D networks to allow read-and-write processes. Moreover, they are very delicate molecules that break down easily and thus, they need to be protected to retain their unique magnetic properties. Owed to their crystalline nature and tunability, metal-organic frameworks (MOFs) provide an excellent means to overcome this challenge. We investigated the unprecedented incorporation of SMMs into multidimensional MOF matrixes, yielding new nanostructured composite materials that combines key SMM properties with the functional properties of MOFs. We believe that these findings might be crucial for the development of spintronics in real world applications. In this presentation we will focus on the fundamental understanding in the exciting structure-property relationships of these SMM@MOF composite materials.

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Wednesday, April 12, 2017

3:00 p.m.
Snell Hall Room 175

Ph.D. Defense

Xiaobo Liu, Ph.D. Candidate

Clarkson University

will speak on

“Design and Development of Electrochemical Biosensors for Real-time Monitoring of Oxidative Stress and Efficient Bacteria Detection"

Abstract:

The need for simple, rapid, cost-effective and field-portable screening methods has boosted the development of biosensors in various fields, ranging from medical diagnosis to food safety and environmental monitoring applications. The current analytical methodologies rely on the use of laboratory-based instrumentation which are complex, expensive and require skilled personnel.  In addition to the broad range of applications, biosensors can be used to study biologically-relevant molecules, their quantitation, kinetics and release in biological models. This presentation will describe design and development of electrochemical biosensors for the detection of reactive oxygen and nitrogen species (ROS/RNS) that play a major role in oxidative stress. Performance characteristics and applicability of these biosensors for the study of oxidative stress-related mechanisms in bacteria, zebrafish embryos and in a mouse model of intestinal ischemia-reperfusion injury are demonstrated. A label-free electrochemical biosensor which utilizes the recognition properties of synthetic antimicrobial peptides for bacteria is also described.

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Friday, April 7, 2017

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

Roshanak Aslebagh, M.S., Ph.D. Candidate

Clarkson University

will speak on

Proteomics Analysis of Human Breast Milk to Assess Breast Cancer Risk"

Abstract:

Detection of breast cancer (BC) in young women is challenging because mammography, the most common tool for detecting BC, is not effective on the dense breast tissue characteristic of young women. In addition to the limited means for detecting their BC, young women face a transient increased risk of pregnancy-associated BC. As a consequence, reproductively active women could benefit significantly from a tool that provided them with accurate risk assessment and early detection of BC. One potential method for detection of BC is biochemical monitoring of proteins and other molecules in bodily fluids such as serum, nipple aspirate, ductal lavage, tear, urine, saliva and breast milk. Of all these fluids, only breast milk provides access to a large volume of breast tissue, in the form of exfoliated epithelial cells, and to the local breast environment, in the form of molecules in the milk. Thus, analysis of breast milk is a non-invasive method with significant potential for assessing BC risk. Here we analyzed human breast milk by mass spectrometry (MS)-based proteomics to build a biomarker signature for early detection of BC.

Milk samples provided paired-groups (cancer versus control) for analysis of differentially expressed proteins. We performed two types of comparisons: 1. within woman comparisons (milk from a diseased breast versus a healthy breast of the same woman) and 2. across women comparisons (milk from a woman with cancer versus a woman without cancer). Despite a wide range in the time between milk donation and cancer diagnosis, the levels of some proteins differed significantly between cancer and control in several of the comparison groups. These pilot data are supportive of the idea that molecular analysis of breast milk will identify proteins informative for early detection and accurate assessment of BC risk, and warrant further research.

R. Aslebagh Semniar 2017

Professor Costel Darie (right) with Ph.D. Candidate Roshanak Aslebagh

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Friday, March 31, 2017

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

Dr. Mehmet V. Yigit

Department of Chemistry

SUNY Albany

will speak on

“Novel Chemical Approaches for Reprogrammable Visual Detection and Controllable Drug Activation"

Abstract:

We have coupled the DNA polymerization capability of hybridization chain reaction (HCR) with the plasmonic properties of gold nanoparticles to develop a highly sensitive, reprogrammable and multiplexed detection. We have used this approach for visual and spectroscopic detection of low copies of three different miRNAs linked to cancer progression; four different oligonucleotides specific to subtypes an infectious disease and two environmentally important metal ions for monitoring water and soil contamination. As little as 20 femtomole of each miRNA was detected visually without using any analytical instrument. The detection can be performed individually or simultaneously in seven different combinations. On the other hand, the oligonucleotides specific to four subtypes an infectious disease can be detected individually or simultaneously in liquid biopsy mimics (urine) in sixteen different combinations using a single gold nanoparticle template. The results demonstrated that our system is extremely sensitive and selective to specific subtype generating no false-positive or false-negative results. Finally this approach was adapted for detection environmentally important heavy metal ions. As low as 10 pM of two different metal ions was detected visually in water and soil samples. We will also present several innovative approaches for activating in-cell small molecule and RNA therapeutics using bio-orthogonally responsive iron oxide nanoparticles. 

Yigit Seminar

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Friday, March 17, 2017

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

Dr. Marius Mihasan

Faculty of Biology

Alexandru Ioan Cuza University of Iasi Romania

will speak on

“Arthrobacter nicotinovorans pAO1 – Why do we need its proteome?"

Abstract:

The nicotine alkaloid produced by the tobacco plant plays an important role in smoking addiction and is able to modulate brain functions. In high doses nicotine is potentially lethal to humans. In addition, large quantities of waste with high concentrations of nicotine are generated during the tobacco-manufacturing process and are simply discarded into the environment. Nicotine metabolizing bacteria might offer a unique way of exploiting nicotine waste for the production of ''green'' chemicals and for understanding smoking addiction.

Arthrobacter nicotinovorans is such a bacteria able to metabolize nicotine and use it at its carbon and nitrogen source. This metabolic ability is encoded by a large catabolic plasmid - pAO1. Although the genetic organization, function, origin and evolution of the pAO1 plasmid have been extensively studied, several key points such as regulation of the nicotine catabolic genes, nicotine transport systems or metabolic fate of the pyridine ring are still missing.

We have shown that nicotine-derivatives produced by Arthrobacter nicotinovorans improve brain functions. Most notably, 6-hydroxy-nicotine (6HNic) is able .to improve short and long-term memory, probably by binding to specific acetylcholine receptors. A genetically engineered Arthrobacter strain allows us to easily produce 6HNic and we are currently focusing on studying its half-live, metabolism and toxicity in lab-rats. 

M. Mihasan Seminar 2017

Professor Costel Darie (right) with Dr. Marius Mihasan

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Friday, March 10, 2017

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

Dr. Eunsu Paek

Department of Chemical and Biomolecular Engineering

Clarkson University

will speak on

“Design principles for graphene-based materials to enhance supercapacitor performance"

Abstract:

Carbon-based nanomaterials such as graphene and nanotubes are a promising class of electrodes for electrochemical double layer capacitors, due to their high accessible surface area, high electrical conductivity, and tunability through functionalization. A series of recent studies have shown that chemically and mechanically modified graphene electrodes can have improved capacitance, which has been through typically to be associated with the increased double layer capacitance from a high BET surface area or an enhanced electrolyte-electrode interfacial interaction. However, the influence of the electrode’s quantum capacitance is relatively unknown. In this talk, we will present a computational framework based on density functional theory and classical molecular dynamics to explore the relative contributions of the quantum capacitance of electrode (CQ) and the electric double layer (CD) capacitance to the total interfacial capacitance (CT) for various carbon electrode systems in ionic liquids (ILs). For instance, our recent study suggests that N-doping leads to significant enhancement in CQ as a result of electronic structure modifications while there is virtually no change in CD. We will also discuss the impact of the chemical and/or mechanical modifications of graphene-like electrodes on the CT and the design principles to enhance supercapacitor performance.

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Friday, March 3, 2017

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

Kelly Tillman

Clarkson University

will speak on

“Biodegradable Polyanhydride Systems via Thiol-Ene Click Polymerizations: Applications in Drug Delivery and Shape Memory"

Abstract:

It has been proven that polyanhydrides may undergo surface erosion allowing for near zero-order drug release kinetics and through the manipulation of monomer composition it is possible to tailor the degradation time frame. We have recently demonstrated that certain polyanhydride systems have unique capabilities when applied to shape memory applications. Shape memory polymers (SMPs) are defined as materials that possess the ability to be deformed and fixed into a temporary shape, and through applied thermal energy or other stimuli return back to the original permanent shape. However, our research has determined that when an anhydride-based crosslinked elastomeric phase is used it has the potential to act as either a typical SMP, a reconfigurable SMP, or transform into a reconfigurable thermoset, depending on the transition temperature used and composition. Through thermomechanical analysis and gel permeation chromatography, we have proven that these unique capabilities are caused by a dynamic covalent exchange reaction occurring in the elastomeric phase amongst the anhydride functionality at elevated temperatures (T>50°C), which could potentially be used for self-healing properties.

Fig 1

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Friday, February 24, 2017

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

Ashkan Koushanpour

Clarkson University

will speak on

“Enzymatic biofuel cell based on carbon fiber functionalized with in situ green synthesis of graphene nanosheets"

Abstract:

Sustainable power sources, which derive energy from renewable resources, with the ability for miniaturization allowing use as implantable devices, have recently claimed significant attention. Due to recent increase in high demand of in situ and continuous source of power for biomedical devices the need for a special design is imperative. Enzymatic biofuel cells by far are believed to be the best available alternatives for this aim as they don’t present hurdles such as harsh operating conditions, toxicity, and low reliability.

Here a membraneless enzymatic biofuel cell based on a novel electrode material developed by in situ green electrochemical synthesis of graphene nano sheets onto 3D carbon fiber electrode is introduced. The modified electrode for electrocatalytic oxidation of NADH was developed using Meldola’s Blue (MB) while the reduction of H2O2 was catalyzed by hemin. Both catalysts were adsorbed on the graphene flakes due to their π-π stacking. Following that, the MB and the hemin were further modified with glucose dehydrogenase (GDH) and glucose oxidase (GOx) respectively. The enzymatic reaction occurring on the electrode surface in the presence of Glucose and O2 will result in production of NADH and H2O2 which will immediately be oxidized and reduced respectively at the biocatalytic modified electrodes. This enzyme-based biofuel cell is operated in a human serum solution modelling an implantable device powered from natural biofluids and has the potential for miniaturization.

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Friday, February 17, 2017

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

Eduard Dumitrescu

Clarkson University

will speak on

Chemical processes and environmental toxicity of CMP particles and additives"

Abstract:

Chemical mechanical planarization (CMP) is a wafer polishing technique used to remove excess deposited materials during the manufacturing of integrated circuit chips in semiconductor industry. The CMP slurry typically contains an aqueous dispersion of metal oxide particles (e.g. silica, ceria, alumina) and chemical additives. The chemical additives in the slurry selectively dissolve the materials present on the wafer surface, while the particles mechanically remove the chemically modified surface film through abrasion. Both particles and chemical additives are eliminated through CMP effluents along with dissolved and particulate materials removed by the polishing process. Therefore, knowledge of the interactions between metal oxide particles and additives, and their environmental toxicity is of great importance. This presentation will describe the study of environmental and chemical processes implicating CMP particles and additives. Toxicity of three common slurry formulations and their resulting waste was assessed using zebrafish embryos model. The toxicological characterization is discussed in relation to the physicochemical changes and interactions between particles and chemical additives. These results provide toxicological information of realistic CMP slurries and their polishing waste, and should be useful for the rational design of more environmentally friendly slurries with predictive toxicological impact.  

Dumitrescu Seminar

Professor Silvana Andreescu (right) with Eduard Dumitrescu

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Hopke Distinguished Lecture

Friday, February 10, 2017

3:30 p.m.
Bertrand H. Snell Hall Room 213

Dr. Tami C. Bond

University of Illinois, Urbana-Champaign

will speak on

“Living Scenarios: Chemical Processes, Drivers of Emissions, and Anthrogeoscience"

Abstract:

A major goal of studying chemical processes in the atmosphere is, arguably, developing a predictive capability for the environment. In turn, prediction provides an understanding of consequences and benefits of choices. The implication is that we expect to connect human decisions and physical outcomes—a requirement for responsible stewardship. I will speculate on a ten-year vision for building a predictive framework, from microscopic to macroscopic scales, that leads toward more closely-coupled projections of the connections between humans, infrastructure, social systems, and the environment. Key elements are iterating top-down observations with bottom-up investigation, parsimonious modeling, and judicious collaboration. I will draw examples from my past decade of work, which ranges from real-time characterization of cooking stoves to modeling that resolves individual atmospheric particles to predicting emissions from the United States freight system. The word “scenario” currently means a highly idealized storyline. In the future, I hope that it comes to mean visualization that reflects lived experience. Engineers and scientists play a role in deep understanding of the system, and in appropriate distillation of knowledge.  

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Friday, February 3, 2017

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

Dr. Sam Nugen

Department of Food Science

Cornell University

will speak on

Developing phage-based nanoprobes for rapid pathogen separation and detection"

Abstract:

With increasing concerns regarding the food safety of minimally processed foods such as fruits and vegetables, the food and agriculture industries would benefit greatly from a rapid screening method to determine the presence of potential pathogens in complex matrices. Such a tool could help reduce foodborne illness by allowing farmers, distributors, manufacturers and retailers the ability to determine initial product quality and safety. Advances in nanotechnology have enabled many new platforms which can be used for these purposes.

While the concept of “nanobots” has until now been relegated to science fiction, the Nugen Research Group has utilized advances in nanotechnology and synthetic biology towards the development of hybrid bio-inorganic systems consisting of engineered viruses which have been magnetized through oriented conjugation to magnetic nanoparticles. While nanotechnology has enabled the synthesis and conjugation of high speed magnetic particles, synthetic biology allows us to “program” the virus to perform customized functions.

We are currently developing bacteriophage-based nanoprobes which can separate bacteria from a complex sample, and then specifically select for viable targets for detection. We have genetically engineered the phages to express conjugation moieties on the capsid surface and for the insertion of engineered enzyme genes for a colorimetric detection. Compared with immune-based separation schemes, bacteriophages had a much stronger attachment to the bacterial surface. The attachment was stronger in all extreme sample conditions including pH, temperature, and salt concentration. The phages have been genetically engineered to insert a gene for an engineered enzyme into the target host to allow for a highly specific and sensitive detection of viable bacteria which is low-cost and portable.  

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Friday, January 27, 2017

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

Jesse Pokrzywinski

Clarkson University

will speak on

“Unrivaled Combination of Surface Area and Pore Volume in Micelle-Templated Carbon for Supercapacitor Energy Storage"

Abstract:

We created Immense Surface Area Carbons (ISACs) by a novel heat treatment that stabilized the micelle structure in a biological based precursor prior to high temperature combined activation – pyrolysis. While displaying the morphology akin to commercial activated carbon, ISACs contain an unparalleled combination of electrochemically active surface area and pore volume (up to 4051 m2 g-1, total pore volume 2.60 cm3 g-1, 76% small mesopores). The carbons also possess the benefit of being quite pure (O and N < 1.9 at.% total), thus allowing for a capacitive response that is primarily EDLC. Tested at commercial mass loadings (~ 10 mg cm-2) ISACs demonstrate exceptional specific capacitance values throughout the entire relevant current density regime, with superior rate capability primarily due to the large fraction of mesopores. In the optimized ISAC, the specific capacitance (Cg) is 540 F g-1 at 0.2 A g-1, 409 F g-1 at 1 A g-1 and 226 F g-1 at a very high current density of 300 A g-1 (~0.15 second charge time). At intermediate and high currents such capacitance values have not been previously reported for any carbon. Tested with a stable 1.8 V window in a 1M Li2SO4 electrolyte, a symmetric supercapacitor cell yields a flat energy – power profile that is fully competitive with organic electrolyte systems: 29 Wh kg-1 at 442 W kg-1 and 17 Wh kg-1 at 3940 W kg-1. The cyclability of symmetric ISAC –cells is also exceptional due to the minimization of faradaic reactions on the carbon surface, with 80% capacitance retention over 100,000 cycles in 1M Li2SO4 and 75,000 cycles in 6M KOH.  

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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.

Brian Panama 2017

Professor Costel Darie (right) with Dr. Brian Panama

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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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