Potsdam, NY, United States

The State University of New York at Potsdam

Potsdam, NY, United States

Not to be confused with the German University of Potsdam in Berlin-BrandenburgThe State University of New York at Potsdam, also known as SUNY Potsdam, or, colloquially, Potsdam, is a public university located in the village of Potsdam in St. Lawrence County, in the U.S. state of New York. Founded in 1816, it is among the 50 oldest colleges in the United States. It is composed of the College of Arts & science, the School of Education and Professional Studies, and the Crane School of Music. Wikipedia.

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Xu H.,The State University of New York at Potsdam | Xu H.,Ludong University | Hepel M.,The State University of New York at Potsdam
Analytical Chemistry | Year: 2011

We report on the development of a fluorescence turn-on "molecular beacon" probe for the detection of glutathione (GSH) and cysteine (Cys). The method is based on a competitive ligation of Hg2+ ions by GSH/Cys and thymine-thymine (T-T) mismatches in a DNA strand of the selfhybridizing beacon strand. The assay relies on the distancedependent optical properties of the fluorophore/quencher pair attached to the ends of the molecular beacon DNA strand. In a very selective coordination of Hg2+ to GSH/Cys, the fluorophore/quencher distance increases concomitantly with the dehybridization and dissociation of the beacon stem T-Hg2+-T due to the extraction of Hg2+ ions. This process results in switching the molecular beacon to the "on" state. The concentration range of the probe is 4-200 nM with the limit of detection (LOD) of 4.1 nM for GSH and 4.2 nM Cys. The probe tested satisfactorily against interference for a range of amino acids including sulfurcontaining methionine. © 2011 American Chemical Society.

Stobiecka M.,The State University of New York at Potsdam | Hepel M.,The State University of New York at Potsdam
Biomaterials | Year: 2011

In view of the prospective applications of polyamine coatings in functional gold nanoparticles for use as carriers in gene delivery systems, in tissue repair and as bactericidal and virucidal non-toxic vehicle, we have investigated the interactions of poly-l-lysine (PLL) with gold nanoparticles (AuNP). Since direct binding of PLL to AuNP is not strong at neutral pH, we have focused on PLL interactions with carboxylated self-assembled monolayers (SAM) on AuNP, such as the citrate-capped AuNP. The double-shell nanoparticles AuNP@Cit/PLL thus produced do not contain any toxic thiols. We have observed strong electrostatic interactions between polycationic chains of PLL and AuNP@Cit in weakly acidic to weakly alkaline solutions (pH 5-9), as evidenced by the bathochromic shift of the local surface plasmon (SP) band and strong increase in resonance elastic light scattering (RELS) intensity. The stoichiometry of interactions evaluated on the basis of RELS data indicates on a hyper-Langmuirian type of interactions with stoichiometric coefficient n = 1.35 (PLL AuNP@Cit). From the RELS titration data, a shift of the deprotonation constant for the bound PLL has been determined (pKa = 11.6 for the bound PLL vs. 10.48 for the free PLL). The deprotonation of PLL leads to AuNP aggregate disassembly, evidenced by sharp RELS decline and hypsochromic shift of SP band. We have found that under these conditions, a residual aggregation due to the interparticle interactions between β-sheets of PLL overcoat become predominant. The molecular dynamics simulations indicate that multiple hydrogen bonds can also be formed between the PLL linker and the shell molecules of AuNP@Cit. The double-shell nanoparticles, AuNP@Cit/PLL, have been shown to attract DNA molecules using highly sensitive RELS measurements presenting the proof-of-concept for the suitability of this non-toxic nanostructured material for gene delivery applications. The advantage of the proposed material is no toxicity related to the ligand release in gene delivery processes in contrast to the thiol-functionalized AuNP. © 2011 Elsevier Ltd.

Stobiecka M.,The State University of New York at Potsdam | Hepel M.,The State University of New York at Potsdam
Biosensors and Bioelectronics | Year: 2011

The influence of potential barriers, introduced to the immunoglobulin-based sensory films, on voltammetric signals of a redox ion probe has been investigated. Films with positive and negative barriers have been examined by depositing charged self-assembled thiol monolayers as the basal layers of a sensory film. The studies performed with monoclonal anti-glutathione antibody-based sensors using ferricyanide ion probe have shown stronger sensor response to the layer components, as well as to the glutathione-capped gold nanoparticles acting as the antigen, for films with positive potential barrier buried deep in the film than for negative barrier films. The larger changes in differential resistance, peak separation and peak heights observed for films with positive barrier have been attributed to different depth and width of the charge distributions in these films. A buried positive barrier with narrow charge distribution width provides the best conditions for film stability and prevents fouling (less ion-exchanges with the medium). This conclusion has been confirmed by calculations of the electric field distribution and potential profiles in immunosensing films performed by numerical integration of Poisson equation for Gaussian distributions of fixed charges of covalently bound components. The proposed fixed-charge model can aid in rapid evaluation of sensory films in sensor development work. The implications of potential barriers in sensory film design are discussed. © 2011 Elsevier B.V.

Bou-Abdallah F.,The State University of New York at Potsdam | Terpstra T.R.,The State University of New York at Potsdam
Biochimica et Biophysica Acta - General Subjects | Year: 2012

Background: In mammals, serum-transferrins transport iron from the neutral environment of the blood to the cytoplasm by receptor-mediated endocytosis. Extensive in-vitro studies have focused on the thermodynamics and kinetics of Fe 3+ binding to a number of transferrins. However, little attention has been given to the thermodynamic characterization of the interaction of transferrin with its receptor. Scope of review: Iron-loaded transferrin (Tf) binds with high affinity to the specific transferrin receptor (TfR) on the cell surface. The Tf-TfR complex is then internalized via receptor mediated endocytosis into an endosome where iron is released. Here, we provide an overview of recent studies that have used ITC to quantify the interaction of various metal ions with transferrin and highlight our current understanding of the thermodynamics of the transferrin-transferrin receptor system at physiological pH. General significance: The interaction of the iron-loaded transferrin with the transferrin receptor is a key cellular process that occurs during the normal course of iron metabolism. Understanding the thermodynamics of this interaction is important for iron homeostasis since the physiological requirement of iron must be appropriately maintained to avoid iron-related diseases. Major conclusions: The thermodynamic data revealed stoichiometric binding of all tested metal ions to transferrin with very high affinities ranging between 10 17 and 10 22 M - 1. Iron-loaded transferrin (monoferric or diferric) is shown to bind avidly (K ~ 10 7-10 8 M - 1) to the receptor at neutral pH with a stoichiometry of one Tf molecule per TfR monomer. Significantly, both the N- and the C-lobe contribute to the binding interaction which is shown to be both enthalpically and entropically driven. This article is part of a Special Issue entitled Transferrins: Molecular mechanisms of iron transport and disorders. © 2011 Elsevier B.V. All rights reserved.

Bou-Abdallah F.,The State University of New York at Potsdam
Biochimica et Biophysica Acta - General Subjects | Year: 2010

Background: Ferritins are ubiquitous and well-characterized iron storage and detoxification proteins. In bacteria and plants, ferritins are homopolymers composed of H-type subunits, while in vertebrates, they typically consist of 24 similar subunits of two types, H and L. The H-subunit is responsible for the rapid oxidation of Fe(II) to Fe(III) at a dinuclear center, whereas the L-subunit appears to help iron clearance from the ferroxidase center of the H-subunit and support iron nucleation and mineralization. Scope of review: Despite their overall similar structures, ferritins from different origins markedly differ in their iron binding, oxidation, detoxification, and mineralization properties. This chapter provides a brief overview of the structure and function of ferritin, reviews our current knowledge of the process of iron uptake and mineral core formation, and highlights the similarities and differences of the iron oxidation and hydrolysis chemistry in a number of ferritins including those from archaea, bacteria, amphibians, and animals. General Significance: Prokaryotic ferritins and ferritin-like proteins (Dps) appear to preferentially use H2O2 over O2 as the iron oxidant during ferritin core formation. While the product of iron oxidation at the ferroxidase centers of these and other ferritins is labile and is retained inside the protein cavity, the iron complex in the di-iron cofactor proteins is stable and remains at the catalytic site. Differences in the identity and affinity of the ferroxidase center ligands to iron have been suggested to influence the distinct reaction pathways in ferritins and the di-iron cofactor enzymes. Major conclusions: The ferritin 3-fold channels are shown to be flexible structures that allow the entry and exit of different ions and molecules through the protein shell. The H- and L-subunits are shown to have complementary roles in iron oxidation and mineralization, and hydrogen peroxide appears to be a by-product of oxygen reduction at the FC of most ferritins. The di-iron(III) complex at the FC of some ferritins acts as a stable cofactor during iron oxidation rather than a catalytic center where Fe(II) is oxidized at the FC followed by its translocation to the protein cavity. © 2010 Elsevier B.V.

Stobiecka M.,The State University of New York at Potsdam | Hepel M.,The State University of New York at Potsdam
Sensors and Actuators, B: Chemical | Year: 2010

A new method for rapid functionalization of metal nanoparticles based on a moderator-tunable 2D nucleation and growth of ligand-exchange domains has been developed for the design of biosensors with nanoparticle-enhanced sensory films and other applications. The proposed functionalization of gold nanoparticles proceeds through the nucleation and avalanche growth of ligand-exchange domains in the self-assembled monolayer film on a gold nanoparticle surface. The nucleation and growth is controllable by a moderator molecule. The experimental system described presents a ligand-exchange process at citrate-capped gold nanoparticles, with homocysteine acting as the incoming ligand and glutathione as the moderator. The kinetics of the nucleation and growth driven ligand-exchange is characterized by a sigmoidal switching function and differs from that of the usually observed Langmuirian pseudo-first-order process corresponding to the random place-exchange. The ultra-fast functionalization process was monitored using resonance elastic light scattering (RELS) spectroscopy and confirmed by UV-vis plasmonic band absorbance measurements. © 2010 Elsevier B.V.

Slatt R.M.,University of Oklahoma | O'Brien N.R.,The State University of New York at Potsdam
AAPG Bulletin | Year: 2011

The identification of "organoporosity" (microscale and nanoscale pores within organic matter in shales), its importance to storage and perhaps transfer of gas molecules through shales, and methods for gathering three-dimensional images of the pores, such as by argon-ion milling and/or field emission scanning electron microscopy, have all been well documented and discussed for unconventional gas shales. However, other types of pores exist within shales that can be important to storage and migration of gas (and oil), and other technologies are available for their identification and imaging. The different pore types found in the Barnett and Woodford shales are described and classified in this article. Copyright © 2011. The American Association of Petroleum Geologists. All rights reserved.

Betrus A.,The State University of New York at Potsdam
TechTrends | Year: 2012

The content and emphasis of the introductory technology courses for undergraduate preservice teachers has historically been examined, with the earliest study conducted by Stracke in 1932. In an attempt to identify trends in the course DeKieffer conducted a series of studies over ten year intervals, in 1947, 1957, 1967, and 1977. In 2000 the first in a similar series of ten-year studies was conducted, and this 2010 study is the first update to that study. Results indicate that the introductory technology course has gone through a particularly dynamic era recently, with nearly half of all topics appearing as new in 2010. Of particular note among the new topics are SMART Boards and Web 2. 0 technologies such as Blogs, Wikis, and Professional and Social Networking Sites. © 2012 Springer Science+Business Media New York.

Stobiecka M.,The State University of New York at Potsdam | Hepel M.,The State University of New York at Potsdam
Physical Chemistry Chemical Physics | Year: 2011

The optical properties of a photoluminescent dye rhodamine B (RhB) interacting with gold nanoparticles (AuNP) have been investigated using plasmonic absorbance, fluorescence, and resonance elastic light scattering (RELS) spectroscopy. We have found that these interactions result in a multimodal coupling that influence optical transitions in RhB. In absorbance measurements, we have observed for the first time the coupling resulting in strong screening of RhB π-π* transitions, likely caused by a contact adsorption of RhB on a conductive surface of AuNP. The nanoparticles quench also very efficiently the RhB fluorescence. We have determined that the static quenching mechanism with a non-Förster fluorescence resonance energy transfer (FRET) from RhB molecules to AuNP is involved. The Stern-Volmer dependence F 0/F = f(Q) shows an upward deviation from linearity, attributed to the ultra-high quenching efficiency of AuNP leading to the new extended Stern-Volmer model. A sharp RELS peak of RhB alone (λ max = 566 nm) has been observed for the first time and attributed to the resonance fluorescence and enhanced scattering. This peak is completely quenched in the presence of AuNP 22nm. Our quantum mechanical calculations confirm that the distance between AuNP surface and conjugated π-electron system in RhB is well within the range of plasmonic fields extending from AuNP. The optical transition coupling to plasmonic oscillations and the efficient energy transfer due to the interactions of fluorescent dyes with nanoparticles are important for biophysical studies of life processes and applications in nanomedicine. © the Owner Societies 2011.

Reyome N.D.,The State University of New York at Potsdam
Journal of Aggression, Maltreatment and Trauma | Year: 2010

Within the last three decades, researchers have begun to investigate the long-term consequences of childhood emotional maltreatment on interpersonal and intrapersonal functioning. These investigations have led to the realization that survivors of childhood emotional maltreatment suffer from myriad psychological and social difficulties. These difficulties influence the quality and nature of intimate relationships formed by emotional abuse survivors. The empirical literature looking at the effect of childhood emotional maltreatment on intimate relationships is summarized and discussed. Implications of the current body of research for future research and clinical practice are addressed. Copyright © Eileen L. Zurbriggen.

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