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Biological and Chemical Physics

2016

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Articles 1 - 30 of 38

Full-Text Articles in Physics

Enhancement Of The Superconducting Gap By Nesting In Cakfe4as4: A New High Temperature Superconductor, Daixiang Mou, Tai Kong, William R. Meier, Felix Lochner, Lin-Lin Wang, Qisheng Lin, Yun Wu, S. L. Bud’Ko, Ilya Eremin, Duane D. Johnson, Paul C. Canfield, Adam Kaminski Dec 2016

Enhancement Of The Superconducting Gap By Nesting In Cakfe4as4: A New High Temperature Superconductor, Daixiang Mou, Tai Kong, William R. Meier, Felix Lochner, Lin-Lin Wang, Qisheng Lin, Yun Wu, S. L. Bud’Ko, Ilya Eremin, Duane D. Johnson, Paul C. Canfield, Adam Kaminski

Chemistry Publications

We use high resolution angle resolved photoemission spectroscopy and density functional theory with measured crystal structure parameters to study the electronic properties of CaKFe4As4. In contrast to the related CaFe2As2 compounds, CaKFe4As4 has a high Tc of 35 K at stochiometric composition. This presents a unique opportunity to study the properties of high temperature superconductivity in the iron arsenides in the absence of doping or substitution. The Fermi surface consists of several hole and electron pockets that have a range of diameters. We find that the values of the superconducting gap are nearly isotropic (within the explored portions of the ...


Point Island Models For Nucleation And Growth Of Supported Nanoclusters During Surface Deposition, Yong Han, Émilie Gaudry, Tiago J. Oliveira, James W. Evans Dec 2016

Point Island Models For Nucleation And Growth Of Supported Nanoclusters During Surface Deposition, Yong Han, Émilie Gaudry, Tiago J. Oliveira, James W. Evans

Physics and Astronomy Publications

Point island models (PIMs) are presented for the formation of supported nanoclusters (or islands) during deposition on flat crystalline substrates at lower submonolayer coverages. These models treat islands as occupying a single adsorption site, although carrying a label to track their size (i.e., they suppress island structure). However, they are particularly effective in describing the island size and spatial distributions. In fact, these PIMs provide fundamental insight into the key features for homogeneous nucleation and growth processes on surfaces. PIMs are also versatile being readily adapted to treat both diffusion-limited and attachment-limited growth and also a variety of other ...


Capture Zone Area Distributions For Nucleation And Growth Of Islands During Submonolayer Deposition, Yong Han, Maozhi Li, James W. Evans Dec 2016

Capture Zone Area Distributions For Nucleation And Growth Of Islands During Submonolayer Deposition, Yong Han, Maozhi Li, James W. Evans

Physics and Astronomy Publications

A fundamental evolution equation is developed to describe the distribution of areas of capture zones (CZs) associated with islands formed by homogeneous nucleation and growth during submonolayer deposition on perfect flat surfaces. This equation involves various quantities which characterize subtle spatial aspects of the nucleation process. These quantities in turn depend on the complex stochastic geometry of the CZ tessellation of the surface, and their detailed form determines the CZ area distribution (CZD) including its asymptotic features. For small CZ areas, behavior of the CZD reflects the critical island size, i. For large CZ areas, it may reflect the probability ...


Adsorption Of Dysprosium On The Graphite (0001) Surface: Nucleation And Growth At 300 K, Emma J. Kwolek, Huaping Lei, Ann Lii-Rosales, Mark Wallingford, Yinghui Zhou, Cai-Zhuang Wang, Michael C. Tringides, James W. Evans Dec 2016

Adsorption Of Dysprosium On The Graphite (0001) Surface: Nucleation And Growth At 300 K, Emma J. Kwolek, Huaping Lei, Ann Lii-Rosales, Mark Wallingford, Yinghui Zhou, Cai-Zhuang Wang, Michael C. Tringides, James W. Evans

Physics and Astronomy Publications

We have studied nucleation and growth of Dy islands on the basal plane of graphite at 300 K using scanning tunneling microscopy, density functional theory (DFT) in a form that includes van der Waals interactions, and analytic theory. The interaction of atomic Dy with graphite is strong, while the diffusion barrier is small. Experiment shows that at 300 K, the density of nucleated islands is close to the value predicted for homogeneous nucleation, using critical nucleus size of 1 and the DFT-derived diffusion barrier. Homogeneous nucleation is also supported by the monomodal shape of the island size distributions. Comparison with ...


Solution Of Population Balance Equations In Applications With Fine Particles: Mathematical Modeling And Numerical Schemes, Tan Trung Nguyen, Frédérique Laurent, Rodney O. Fox, Marc Massot Nov 2016

Solution Of Population Balance Equations In Applications With Fine Particles: Mathematical Modeling And Numerical Schemes, Tan Trung Nguyen, Frédérique Laurent, Rodney O. Fox, Marc Massot

Chemical and Biological Engineering Publications

The accurate description and robust simulation, at relatively low cost, of global quantities (e.g. number density or volume fraction) as well as the size distribution of a population of fine particles in a carrier fluid is still a major challenge for many applications. For this purpose, two types of methods are investigated for solving the population balance equation with aggregation, continuous particle size change (growth and size reduction), and nucleation: the extended quadrature method of moments (EQMOM) based on the work of Yuan et al.[52]and a hybrid method (TSM) between the sectional and moment methods, considering two ...


Splitting Nodes And Linking Channels: A Method For Assembling Biocircuits From Stochastic Elementary Units, Cameron Ferwerda, Ovidiu Lipan Nov 2016

Splitting Nodes And Linking Channels: A Method For Assembling Biocircuits From Stochastic Elementary Units, Cameron Ferwerda, Ovidiu Lipan

Physics Faculty Publications

Akin to electric circuits, we construct biocircuits that are manipulated by cutting and assembling channels through which stochastic information flows. This diagrammatic manipulation allows us to create a method which constructs networks by joining building blocks selected so that (a) they cover only basic processes; (b) it is scalable to large networks; (c) the mean and variance-covariance from the Pauli master equation form a closed system; and (d) given the initial probability distribution, no special boundary conditions are necessary to solve the master equation. The method aims to help with both designing new synthetic signaling pathways and quantifying naturally existing ...


125te Nmr And Seebeck Effect In Bi2te3 Synthesized From Stoichiometric And Te-Rich Melts, E. M. Levin, Trevor M. Riedemann, A. Howard, Na Hyun Jo, Sergey L. Bud’Ko, Paul C. Canfield, Thomas A. Lograsso Nov 2016

125te Nmr And Seebeck Effect In Bi2te3 Synthesized From Stoichiometric And Te-Rich Melts, E. M. Levin, Trevor M. Riedemann, A. Howard, Na Hyun Jo, Sergey L. Bud’Ko, Paul C. Canfield, Thomas A. Lograsso

Materials Science and Engineering Publications

Bi2Te3 is a well-known thermoelectric material and, as a new form of quantum matter, a topological insulator. Variation of local chemical composition in Bi2Te3 results in formation of several types of atomic defects, including Bi and Te vacancies and Bi and Te antisite defects; these defects can strongly affect material functionality via generation of free electrons and/or holes. Nonuniform distribution of atomic defects produces electronic inhomogeneity, which can be detected by 125Te nuclear magnetic resonance (NMR). Here we report on 125Te NMR and Seebeck effect (heat to electrical energy conversion) for two single crystalline samples: (#1) grown from stoichiometric ...


Catalytic Conversion In Nanoporous Materials: Concentration Oscillations And Spatial Correlations Due To Inhibited Transport And Intermolecular Interactions, Andrés García, James W. Evans Nov 2016

Catalytic Conversion In Nanoporous Materials: Concentration Oscillations And Spatial Correlations Due To Inhibited Transport And Intermolecular Interactions, Andrés García, James W. Evans

Physics and Astronomy Publications

We show that steady-state catalytic conversion in nanoporous materials can occur in a quasi-counter-diffusion mode with the reactant (product) concentration strongly decaying (growing) into the pore, but also with oscillations in the total concentration. These oscillations reflect the response of the fluid to the transition from an extended to a confined environment near the pore opening. We focus on the regime of strongly inhibited transport in narrow pores corresponding to single-file diffusion. Here, limited penetration of the reactant into the pores and the associated low reaction yield is impacted by strong spatial correlations induced by both reaction (non-equilibrium correlations) and ...


Heart Attack Physics, John Zwart Nov 2016

Heart Attack Physics, John Zwart

Faculty Work Comprehensive List

I recently had a first-hand opportunity to learn some interesting biomedical applications of physics which provide application examples for introductory classes. While there were many such applications, from X-rays to ultrasonic imaging, I’ll focus on fluid flow through clogged coronary arteries and the use of radioactive materials in a nuclear stress test.


Comparison Of S-Adsorption On (111) And (100) Facets Of Cu Nanoclusters, Jeffrey S. Boschen, Jiyoung Lee, Theresa L. Windus, James W. Evans, Patricia A. Thiel, Da-Jiang Liu Oct 2016

Comparison Of S-Adsorption On (111) And (100) Facets Of Cu Nanoclusters, Jeffrey S. Boschen, Jiyoung Lee, Theresa L. Windus, James W. Evans, Patricia A. Thiel, Da-Jiang Liu

Physics and Astronomy Publications

In order to gain insight into the nature of chemical bonding of sulfur atoms on coinage metal surfaces, we compare the adsorption energy and structural parameters for sulfur at four-fold hollow (4fh) sites on (100) facets and at three-fold hollow (3fh) sites on (111) facets of Cu nanoclusters. Consistent results are obtained from localized atomic orbital and plane-wave based density functional theory using the same functionals. PBE and its hybrid counterpart (PBE0 or HSE06) also give similar results. 4fh sites are preferred over 3fh sites with stronger bonding by ∼0.6 eV for nanocluster sizes above ∼280 atoms. However, for ...


Exposure Of Fibrinogen And Thrombin To Nitric Oxide Donor Prolinonoate Affects Fibrin Clot Properties, Christine C. Helms, Shannon Kapadia, Anne C. Gilmore, Zhexi Lu, Swati Basu, Daniel B. Kim-Shapiro Oct 2016

Exposure Of Fibrinogen And Thrombin To Nitric Oxide Donor Prolinonoate Affects Fibrin Clot Properties, Christine C. Helms, Shannon Kapadia, Anne C. Gilmore, Zhexi Lu, Swati Basu, Daniel B. Kim-Shapiro

Physics Faculty Publications

Fibrin fibers form the structural backbone of blood clots. The structural properties of fibrin clots are highly dependent on formation kinetics. Environmental factors such as protein concentration, pH, salt, and protein modification, to name a few, can affect fiber kinetics through altered fibrinopeptide release, monomer association, and/or lateral aggregation. The objective of our study was to determine the effect of thrombin and fibrinogen exposed to nitric oxide on fibrin clot properties. ProliNONOate (5 [mu]mol/l) was added to fibrinogen and thrombin before clot initiation and immediately following the addition of thrombin to the fibrinogen solution. Resulting fibrin fibers ...


Dealloying Behavior Of Nico And Nicocu Thin Films, Benjamin Peecher, Jennifer R. Hampton Oct 2016

Dealloying Behavior Of Nico And Nicocu Thin Films, Benjamin Peecher, Jennifer R. Hampton

Faculty Publications

Porous metals and alloys, such as those fabricated via electrochemical dealloying, are of interest for a variety of energy applications, ranging from their potential for enhanced catalytic behavior to their use as high surface area supports for pseudocapacitor materials. Here, the electrochemical dealloying process was explored for electrodeposited binary NiCo and ternary NiCoCu thin films. For each of the four different metal ratios, films were dealloyed using linear sweep voltammetry to various potentials in order to gain insight into the evolution of the film over the course of the linear sweep. Electrochemical capacitance, scanning electron microscopy, and energy dispersive X-ray ...


Emergence Of A Potent Multidrug Efflux Pump Variant That Enhances Campylobacter Resistance To Multiple Antibiotics, Hong Yao, Zhangqi Shen, Yang Wang, Fengru Deng, Dejun Liu, Gaowa Naren, Lei Dai, Chih-Chia Su, Bing Wang, Shaolin Wang, Congming Wu, Edward W. Yu, Qijing Zhang, Jianzhong Shen Sep 2016

Emergence Of A Potent Multidrug Efflux Pump Variant That Enhances Campylobacter Resistance To Multiple Antibiotics, Hong Yao, Zhangqi Shen, Yang Wang, Fengru Deng, Dejun Liu, Gaowa Naren, Lei Dai, Chih-Chia Su, Bing Wang, Shaolin Wang, Congming Wu, Edward W. Yu, Qijing Zhang, Jianzhong Shen

Veterinary Microbiology and Preventive Medicine Publications

Bacterial antibiotic efflux pumps are key players in antibiotic resistance. Although their role in conferring multidrug resistance is well documented, the emergence of “super” efflux pump variants that enhance bacterial resistance to multiple drugs has not been reported. Here, we describe the emergence of a resistance-enhancing variant (named RE-CmeABC) of the predominant efflux pump CmeABC in Campylobacter, a major zoonotic pathogen whose resistance to antibiotics is considered a serious antibiotic resistance threat in the United States. Compared to the previously characterized CmeABC transporters, RE-CmeABC is much more potent in conferring Campylobacter resistance to antibiotics, which was shown by increased MICs ...


Koh Etching Of (100) Si Wafer, No 2, Inayat Bajwa Sep 2016

Koh Etching Of (100) Si Wafer, No 2, Inayat Bajwa

Protocols and Reports

This report describes KOH etching of (100) Si wafer through a hard mask of silicon oxide, and reveals that the scattered etch rate is ascribed to the etch rates of the different crystal planes exposed during the etching.


Directed Self-Assembly Of Block Copolymer, No1, Hiromichi Yamamoto Aug 2016

Directed Self-Assembly Of Block Copolymer, No1, Hiromichi Yamamoto

Protocols and Reports

The PS-rich and neutral PS-b-PMMA block copolymer (BCP) films were spin coated on the neutral random copolymer hydroxyl-terminated PS-r-PMMA layers grafted on the native oxide and 50 nm thick PECVD amorphous silicon oxide layers. Relationship between the grafting density of BCP and surface density of hydroxyl moiety on silicon oxide is discussed. Furthermore, optimization of annealing BCP films is reported, and wetted and de-wetted BCP films are shown in optical microscope images. In addition, finger print and nanopore structures of BCP films are also indicated in SEM images.


In Vitro Monitoring Of Time And Dose Dependent Cytotoxicity Of Aminated Nanoparticles Using Raman Spectroscopy, Esen Efeoglu, Alan Casey, Hugh Byrne Jul 2016

In Vitro Monitoring Of Time And Dose Dependent Cytotoxicity Of Aminated Nanoparticles Using Raman Spectroscopy, Esen Efeoglu, Alan Casey, Hugh Byrne

Articles

No abstract provided.


Simulation Model Of An Automatic Commercial Ice Machine, Haithem Murgham, David Myszka, Vijay Bahel, Rajan Rajendran, Kurt Knapke, Suresh Shivashankar, Kyaw Wynn Jul 2016

Simulation Model Of An Automatic Commercial Ice Machine, Haithem Murgham, David Myszka, Vijay Bahel, Rajan Rajendran, Kurt Knapke, Suresh Shivashankar, Kyaw Wynn

Mechanical and Aerospace Engineering Faculty Publications

Automatic commercial ice-making machines that produce a batch of cube ice at regular intervals are known as “cubers." Such machines are commonly used in food service, food preservation, hotel, and health service industries. The machines are typically rated for the weight of ice produced over a 24-hour period at ambient air temperatures of 90°F and water inlet temperature of 70°F.

These cubers typically utilize an air-cooled, vapor-compression cycle to freeze circulating water flowing over an evaporator grid. Once a sufficient amount ice is formed, a valve switches to enable a harvest mode, where the compressor’s discharge gas ...


Using Zinc Finger Proteins As A Diagnostic Tool For The Detection Of A Cancer Biomarker, Anu Kini Jul 2016

Using Zinc Finger Proteins As A Diagnostic Tool For The Detection Of A Cancer Biomarker, Anu Kini

Masters Theses & Specialist Projects

RASSF1A is a tumor suppressor gene which loses its function due to methylation of CpG islands on its promoter region. Detection of methylation leads to early diagnosis of cancer.

Zinc finger proteins are capable of detecting a specific DNA sequence and Methyl binding domain can bind to the methyl group on the CpG, using this idea mCpG SEER- Lac system makes use of a split protein, β-lactamase. Lac A attached to the ZFP and Lac B attached to the MBD protein. On binding to the DNA, the Lac A and Lac B come in close proximity with each other causing ...


Communication: Visualization And Spectroscopy Of Defects Induced By Dehydrogenation In Individual Silicon Nanocrystals, Dmitry A. Kislitsyn, Jon M. Mills, Vancho Kocevski, Sheng-Kuei Chiu, William J.I. Debenedetti, Christian F. Gervasi, Benjamen N. Taber, Ariel E. Rosenfield, Olle Eriksson, Ján Rusz, Andrea Mitchell Goforth, George V. Nazin Jun 2016

Communication: Visualization And Spectroscopy Of Defects Induced By Dehydrogenation In Individual Silicon Nanocrystals, Dmitry A. Kislitsyn, Jon M. Mills, Vancho Kocevski, Sheng-Kuei Chiu, William J.I. Debenedetti, Christian F. Gervasi, Benjamen N. Taber, Ariel E. Rosenfield, Olle Eriksson, Ján Rusz, Andrea Mitchell Goforth, George V. Nazin

Chemistry Faculty Publications and Presentations

We present results of a scanning tunneling spectroscopy (STS) study of the impact of dehydrogenation on the electronic structures of hydrogen-passivated silicon nanocrystals (SiNCs) supported on the Au(111)surface. Gradual dehydrogenation is achieved by injecting high-energy electrons into individual SiNCs, which results, initially, in reduction of the electronic bandgap, and eventually produces midgap electronic states. We use theoretical calculations to show that the STS spectra of midgap states are consistent with the presence of silicon dangling bonds, which are found in different charge states. Our calculations also suggest that the observed initial reduction of the electronic bandgap is attributable ...


An Experimental And Theoretical Study Of Ã2A"Π–X~2A' Band System Of The Jet-Cooled Hbbr/Dbbr Free Radical, Mohammed Gharaibeh, Dennis J. Clouthier, Riccardo Tarroni Jun 2016

An Experimental And Theoretical Study Of Ã2A"Π–X~2A' Band System Of The Jet-Cooled Hbbr/Dbbr Free Radical, Mohammed Gharaibeh, Dennis J. Clouthier, Riccardo Tarroni

Chemistry Faculty Publications

The electronic spectra of the HBBr and DBBr free radicals have been studied in depth. These species were prepared in a pulsed electric discharge jet using a precursor mixture of BBr3 vapor and H2 or D2 in high pressure argon. Transitions to the electronic excited state of the jet-cooled radicals were probed with laser-induced fluorescence and the ground state energy levels were measured from the single vibronic level emission spectra. HBBr has an extensive band system in the red which involves a linear-bent transition between the two Renner-Teller components of what would be a 2Π state ...


A Comparison Of Catabolic Pathways Induced In Primary Macrophages By Pristine Single Walled Carbon Nanotubes And Pristine Graphene, Caroline More, Jennifer Mcintyre, Luke O'Neill, Hugh Byrne Jun 2016

A Comparison Of Catabolic Pathways Induced In Primary Macrophages By Pristine Single Walled Carbon Nanotubes And Pristine Graphene, Caroline More, Jennifer Mcintyre, Luke O'Neill, Hugh Byrne

Articles

Understanding the correlation between the physico-chemical properties of carbonaceous nanomaterials and how these properties impact on cells and subcelluar mechanisms is critical to their risk assessment and safe translation into newly engineered devices. Here the toxicity, uptake and catabolic response of primary human macrophages to pristine graphene (PG) and pristine single walled carbon nanotubes (pSWCNT) are explored, compared and contrasted. The nanomaterial toxicity was assessed using three complementary techniques (live-dead assay, real time impedance technique and confocal microscopic analysis), all of which indicated no signs of acute cytotoxicity in response to PG or pSWCNT. Transmission electron microscopy (TEM) demonstrated that ...


Synthesis And Characterization Of Organic-Inorganic Hybrid Materials For Thermoelectric Devices, Paige M. Huzyak Apr 2016

Synthesis And Characterization Of Organic-Inorganic Hybrid Materials For Thermoelectric Devices, Paige M. Huzyak

Masters Theses & Specialist Projects

The development of organic-inorganic hybrid materials is of great interest in thermoelectrics for its potential to combine the desirable characteristics of both classes of materials. Thermoelectric materials must combine low thermal conductivity with high electrical conductivity, but in most materials, thermal and electrical conductivity are closely related and positively correlated. By combining the low thermal conductivity, flexibility, facile processing, and low cost of organic components with the high electrical conductivity and stability of inorganic components, materials with beneficial thermoelectric properties may be realized.

Here, we describe the synthesis and characterization of anthracene-containing organic-inorganic hybrid materials for thermoelectric purposes. Specifically, POSS-ANT ...


Characteristic Length Scales Of The Secondary Relaxations In Glass-Forming Glycerol, Sudipta Gupta, Eugene Mamontov, Niina Jalarvo, Laura Stingaciu, Michael Ohl Mar 2016

Characteristic Length Scales Of The Secondary Relaxations In Glass-Forming Glycerol, Sudipta Gupta, Eugene Mamontov, Niina Jalarvo, Laura Stingaciu, Michael Ohl

Faculty Publications

We investigate the secondary relaxations and their link to the main structural relaxation in glass-forming liquids using glycerol as a model system. We analyze the incoherent neutron scattering signal dependence on the scattering momentum transfer, Q , in order to obtain the characteristic length scale for different secondary relaxations. Such a capability of neutron scattering makes it somewhat unique and highly complementary to the traditional techniques of glass physics, such as light scattering and broadband dielectric spectroscopy, which provide information on the time scale, but not the length scales, of relaxation processes. The choice of suitable neutron scattering techniques depends on ...


Modification Of The In Vitro Uptake Mechanism And Anti-Oxidant Levels In Hacat Cells And Resultant Changes To Toxicity And Oxidative Stress Of G4 And G6 Poly (Amido Amine) Dendrimer Nanoparticles, Marcus A. Maher, Hugh Byrne Mar 2016

Modification Of The In Vitro Uptake Mechanism And Anti-Oxidant Levels In Hacat Cells And Resultant Changes To Toxicity And Oxidative Stress Of G4 And G6 Poly (Amido Amine) Dendrimer Nanoparticles, Marcus A. Maher, Hugh Byrne

Articles

The mechanism of cellular uptake by endocytosis and subsequent oxidative stress has been identified as the paradigm for the toxic response of cationically surface charged nanoparticles. In an attempt to circumvent the process, the effect of increased cellular membrane permeability on the uptake mechanisms of poly (amidoamine) dendrimers generation 4 (G4) and 6 (G6) in vitro was investigated. Immortalised, non-cancerous human keratinocyte (HaCaT) cells were treated with DL-Buthionine-(S,R)-sulfoximine (BSO). Active uptake of the particles was monitored using fluorescence microscopy to identify and quantify endosomal activity and resultant oxidative stress, manifest as increased levels of reactive oxygen species ...


Chemotherapeutic Efficiency Of Drugs In Vitro: Comparison Of Doxorubicin Exposure In 3d And 2d Culture Matrices, Alan Casey, Mahmoud Gargotti, Franck Bonnier, Hugh Byrne Mar 2016

Chemotherapeutic Efficiency Of Drugs In Vitro: Comparison Of Doxorubicin Exposure In 3d And 2d Culture Matrices, Alan Casey, Mahmoud Gargotti, Franck Bonnier, Hugh Byrne

Articles

The interest in the use of 3D matrices for in vitro analysis, with a view to increasing the relevance of in vitro studies and reducing the dependence on in vivo studies, has been growing in recent years. Cells grown in a 3D in vitro matrix environment have been reported to exhibit significantly different properties to those in a conventional 2D culture environment. However, comparison of 2D and 3D cell culture models have recently been noted to result in differing responses of cytotoxic assays, without any associated change in viability. The effect was attributed to differing conversion rates and effective concentrations ...


Koh Etching Of (100) Si Wafer, No 1, Inayat Bajwa Mar 2016

Koh Etching Of (100) Si Wafer, No 1, Inayat Bajwa

Protocols and Reports

No abstract provided.


Recent Advances In Optical Diagnosis Of Oral Cancers: Review And Future Perspectives, Ola Ibrahim, Hugh Byrne, Fiona Lyng, Surya Singh, Jopi Mikkonen, Arto Koistinen, Arja Kullaa Mar 2016

Recent Advances In Optical Diagnosis Of Oral Cancers: Review And Future Perspectives, Ola Ibrahim, Hugh Byrne, Fiona Lyng, Surya Singh, Jopi Mikkonen, Arto Koistinen, Arja Kullaa

Articles

Optical diagnosis techniques offer several advantages over traditional approaches, including objectivity, speed and cost, and these label-free, non-invasive methods have the potential to change the future work-flow of cancer management. The oral cavity is particularly accessible and thus such methods may serve as alternate/adjunct tools to traditional methods. Recently, in vivo human clinical studies have been initiated with a view to clinical translation of such technologies. A comprehensive review of optical methods in oral cancer diagnosis is presented. Following an introduction to the epidemiology and aetiological factors associated with oral cancers currently employed diagnostic methods and their limitations are ...


Spectral Pre And Post Processing For Infrared And Raman Spectroscopy Of Biological Tissues And Cells, Hugh Byrne, Peter Knief, Mark Keating, Franck Bonnier Mar 2016

Spectral Pre And Post Processing For Infrared And Raman Spectroscopy Of Biological Tissues And Cells, Hugh Byrne, Peter Knief, Mark Keating, Franck Bonnier

Articles

Vibrational Spectroscopy, both infrared absorption and Raman spectroscopy, have attracted increasing attention for biomedical applications, from in vivo and ex vivo disease diagnostics and screening, to in vitro screening of therapeutics. There remain, however, many challenges related to the accuracy of analysis of physically and chemically inhomogeneous samples, across heterogeneous sample sets. Data preprocessing is required to deal with variations in instrumental responses and intrinsic spectral backgrounds and distortions in order to extract reliable spectral data. Data postprocessing is required to extract the most reliable information from the sample sets, based on often very subtle changes in spectra associated with ...


Mapping Of Defects In Individual Silicon Nanocrystals Using Real- Space Spectroscopy, Dmitry A. Kislitsyn, Vancho Kocevski, Jon M. Mills, Sheng-Kuei Chiu, Christian F. Gervasi, Benjamen N. Taber, Ariel E. Rosenfield, Olle Eriksson, Ján Rusz, Andrea Mitchell Goforth, George V. Nazin Mar 2016

Mapping Of Defects In Individual Silicon Nanocrystals Using Real- Space Spectroscopy, Dmitry A. Kislitsyn, Vancho Kocevski, Jon M. Mills, Sheng-Kuei Chiu, Christian F. Gervasi, Benjamen N. Taber, Ariel E. Rosenfield, Olle Eriksson, Ján Rusz, Andrea Mitchell Goforth, George V. Nazin

Chemistry Faculty Publications and Presentations

The photophysical properties of silicon semiconductor nanocrystals (SiNCs) are extremely sensitive to the presence of surface chemical defects, many of which are easily produced by oxidation under ambient conditions. The diversity of chemical structures of such defects and the lack of tools capable of probing individual defects continue to impede understanding of the roles of these defects in SiNC photophysics. We use scanning tunneling spectroscopy to study the impact of surface defects on the electronic structures of hydrogen-passivated SiNCs supported on the Au(111) surface. Spatial maps of the local electronic density of states (LDOS) produced by our measurements allowed ...


Structural Dependence Of The In Vitro Cytotoxicity, Oxidative Stress And Uptake Mechanisms Of Poly(Propylene Imine) Dendritic Nanoparticles, Humza Khalid, Sourav Prasanna Mukherjee, Luke O'Neill, Hugh Byrne Feb 2016

Structural Dependence Of The In Vitro Cytotoxicity, Oxidative Stress And Uptake Mechanisms Of Poly(Propylene Imine) Dendritic Nanoparticles, Humza Khalid, Sourav Prasanna Mukherjee, Luke O'Neill, Hugh Byrne

Articles

The in vitro cytotoxic and intracellular oxidative stress responses to exposure to poly (propylene imine) (PPI) dendritic nanoparticles of increasing generation (number of repeated branching cycles) (G0-G4) were assessed in an immortal non-cancerous human keratinocyte cell-line (HaCaT). Confocal fluorescence microscopy with organelle staining was used to explore the uptake and intracellular trafficking mechanisms. A generation and dose dependent cytotoxic response was observed, increasing according to generation and therefore number of surface amino groups. A comparison of the cytotoxic response of G4 PPI and the related G4 Poly (amido amine) dendrimer indicates that the PPI with the same number of surface ...