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The Μ-Opioid Receptor Gene And Smoking Initiation And Nicotine Dependence, Lan Zhang, Kenneth S. Kendler, Xianging Chen

Psychiatry Publications

The gene encoding the mu-opioid receptor (OPRM1) is reported to be associated with a range of substance dependence. Experiments in knockout mice indicate that the mu-opioid receptor may mediate reinforcing effects of nicotine. In humans, opioid antagonist naltrexone may reduce the reinforcing effects of tobacco smoking. Additionally, the OPRM1 gene is located in a region showing linkage to nicotine dependence. The OPRM1 is thus a plausible candidate gene for smoking behavior. To investigate whether OPRM1 contributes to the susceptibility of smoking initiation and nicotine dependence, we genotyped 11 SNPs in the gene for 688 Caucasian subjects of lifetime smokers and …

Knowledge And Awareness Of Congenital Cytomegalovirus Among Women, Jiyeon Jeon, Marcia Victor, Stuart P. Adler, Abigail Arwady, Gail Demmeler, Karen Fowler, Johanna Goldfarb, Harry Keyserling, Mehran Massoudi, Kristin Richards, Stephanie A. S. Staras, Michael J. Cannon

Pediatrics Publications

Background. Congenital cytomegalovirus (CMV) infection is a leading cause of disabilities in children, yet the general public appears to have little awareness of CMV. Methods. Women were surveyed about newborn infections at 7 different geographic locations. Results. Of the 643 women surveyed, 142 (22%) had heard of congenital CMV. Awareness increased with increasing levels of education (P<.0001). Women who had worked as a healthcare professional had a higher prevalence of awareness of CMV than had other women (56% versus16%, P <.0001). Women who were aware of CMV were most likely to have heard about it from a healthcare provider (54%), but most could not correctly identify modes of CMV transmission or prevention. Among common causes of birth defects and childhood illnesses, women's awareness of CMV ranked last. Conclusion. Despite its large public health burden, few women had heard of congenital CMV, and even fewer were aware of prevention strategies.

Optical Susceptibilities Of Supported Indium Tin Oxide Thin Films, Jonathan L. Humphrey, Darius Kuciauskas

Chemistry Publications

The third-order nonlinear optical susceptibility of indium tin oxide (ITO) thin films on glass substrates, χ(3)ITO, was determined in the near-IR spectral region using degenerate four wave mixing (DFWM)spectroscopy with 100fs laser pulses. A DFWM method for measuring thin films on thick substrates was refined for the characterization of films less than 100nm thick and applied to ∼25nm thick ITO films. It was found that χ(3)ITO is purely electronic at 900–1300nm (11000–7700cm−1) and has a value of (2.16±0.18)×10−18m2V−2. Theχ(3)ITO value reaches (3.36±0.28)×10−18m2V−2 at 1500nm (6700cm−1) due to two-photon absorption by free carriers (electrons). Ultrafast electron relaxation was also observed. The …

Reversible Paramagnetism To Ferromagnetism In Transition Metal-Doped Tio2 Nanocrystals Prepared By Microwave Irradiation, Garry Glaspell, Asit B. Panda, M. S. El-Shall

Chemistry Publications

TiO2nanoparticlesdoped with 1%, 5%, and 10% M (M=Co, Fe, and Ni) were prepared by microwave irradiation and characterized using x-ray diffraction, transmission electron microscopy, and magnetometry. The as-prepared samples are found to be paramagnetic at room temperature, with the magnetic susceptibility following the Curie-Weiss law in the investigated range of 2–300K. However, transformation from paramagnetism to room-temperature ferromagnetism (RTFM) was observed by hydrogenating the samples at 400°C. Reheating in air converted the samples back to paramagnetic while rehydrogenating the samples again induced ferromagnetism. It is argued that the reversible RTFM observed is due to interaction between the dopant metal ions …

Cation Occupancy Determination In Manganese Zinc Ferrites Using Fourier Transform Infrared Spectroscopy, M. D. Shultz, E. E. Carpenter, S. A. Morrison, S. Calvin

Chemistry Publications

The magnetic and electric properties of ferrites are influenced by the cation distribution within the crystalline spinel lattice. Methods such as extended x-ray-absorption fine structure(EXAFS) have been used to determine cation occupancies within the crystalline structure of materials such as manganesezincferrite (MZFO); however, it is not practical to be used for daily analysis. Fourier transform infrared (FTIR)spectroscopy is another technique which has the potential to determine cation occupancy while offering speed and convenience. In the literature it has been demonstrated that in ferrite systems FTIR data can be correlated to cation percentages when comparing tetrahedral (Td) and octahedral (Oh) sites. …

Orientational Correlations In Liquid Acetone And Dimethyl Sulfoxide: A Comparative Study, Sylvia E. Mclain, Alan K. Soper, Alenka Luzar

Chemistry Publications

The structure of acetone and dimethyl sulfoxide in the liquid state is investigated using a combination of neutron diffractionmeasurements and empirical potential structure refinement (EPSR) modeling. By extracting the orientational correlations from the EPSR model, the alignment of dipoles in both fluids is identified. At short distances the dipoles or neighboring molecules are found to be in antiparallel configurations, but further out the molecules tend to be aligned predominately as head to tail in the manner of dipolar ordering. The distribution of these orientations in space around a central molecule is strongly influenced by the underlying symmetry of the central …

Magnetic And Mossbauer Spectroscopy Studies Of Nanocrystalline Iron Oxide Aerogels, E. E. Carpenter, J. W. Long, D. R. Rolison, M. S. Logan, K. Pettigrew, R. M. Stroud, L. Theil Kuhn, B. Rosendahl Hasen, S. Mørup

Chemistry Publications

A sol-gel synthesis was used to produce iron oxide aerogels. These nanocrystalline aerogels have a pore-solid structure similar to silica aerogels but are composed entirely of iron oxides. Mössbauer experiments and x-ray diffraction showed that the as-prepared aerogel is an amorphous or poorly crystalline iron oxide, which crystallized as a partially oxidized magnetite during heating in argon. After further heat treatment in air, the nanocrystallites are fully converted to maghemite. The particles are superparamagnetic at high temperatures, but the magnetic properties are strongly influenced by magnetic interactions between the particles at lower temperatures.

Accuracy And Consistency Of Radiographic Interpretation Among Clinical Instructors In Conjunction With A Training Program, Sharon K. Lanning, Al M. Best, Henry J. Temple, Philip S. Richards, Alllison Carey, Laurie K. Mccauley

Periodontics Publications

There are inaccuracies and inconsistencies of radiographic interpretation among clinical instructors. The purpose of this investigation was to determine if a training program could improve the accuracy and consistency of instructors’ ratings of bone loss. A total of thirty-five clinical instructors consisting of periodontal faculty (periodontists and general dentists), dental hygiene faculty, and periodontal graduate students viewed projected digitized radiographic images and quantified bone loss for twenty-five teeth into four descriptive categories. Ratings of bone loss were made immediately before (pretest) and after (post-test 1) initiation of the training program and then again three months later (post-test 2). Ratings were …

Structure And Bonding Of Au5m (M=Na, Mg, Al, Si, P, And S) Clusters, Chiranjib Majumder, Anil K. Kandalam, Puru Jena

Physics Publications

The atomic and electronic structure of Au5M (M=Na, Mg, Al, Si, P, S, and Au) clusters have been investigated using generalized gradient approximation to the density functional theory. Depending on the nature of interaction with different impurity elements a structural transition from planar to nonplanar configuration has been observed in Au5M. With the exception of S, impurities with p electrons (Al, Si, P) yield nonplanar geometries of Au5M clusters, while those with selectrons (Na, Mg) yield planar geometries. The properties of Au5Scluster are anomalous: The cluster not only has a planar geometry, but also is chemically most stable with the …

Dehydrogenation Mechanism In Catalyst-Activated Mgh2, S. Li, Puru Jena, R. Ahuja

Physics Publications

A small amount of Nb2O5 catalyst is known to substantially improve the desorption thermodynamics and kinetics of MgH2. Using density functional theory in combination with ab initio molecular dynamics simulation, we provide theoretical understanding of the mechanism of dehydrogenation in Nb doped MgH2. We show that the substitution of Nb at the Mg site followed by the clustering of H around Nb is a likely pathway for hydrogen desorption. We also find that dehydrogenation from the vicinity of Mg vacancies is exothermic. However, the vacancies are not likely to play a significant role in hydrogen desorption due to their high …

Effect Of Ti And Metal Vacancies On The Electronic Structure, Stability, And Dehydrogenation Of Na3alh6: Supercell Band-Structure Formalism And Gradient-Corrected Density-Functional Theory, S. Li, Puru Jena

Physics Publications

Electronic and structural properties of sodium-aluminum hexahydride (Na3AlH6) formed during the decomposition reaction of sodium alanate (NaAlH4) and the effects of Ti catalyst are studied using supercell approach and density-functional theory. The preferred site of Ti has been determined by substituting it at both the Na and Al sites and comparing the respective formation energies. The least unfavorable site for Ti is found to be the Al site. To examine the role of Ti substitution on the desorption of hydrogen, the energy cost to remove a H atom from the vicinity of Ti was calculated and compared with that from …

Effect Of Au Coating On The Magnetic And Structural Properties Of Fe Nanoclusters For Use In Biomedical Applications: A Density-Functional Theory Study, Q. Sun, A. K. Kandalam, Q. Wang, Puru Jena, Y. Kawazoe, M. Marquez

Physics Publications

In this paper, we report the first systematic theoretical study of gold-coated iron nanoclusters, aiming at understanding the magnetic properties of this core-shell structure used in biomedical applications. The calculations based on density-functional theory focus on the effect of gold coating on the magnetic and structural properties of iron clusters of various sizes, and the reaction of the bare and coated iron clusters with oxygen. Our results show that the magnetic moment of iron nanocore with gold coating is still significantly higher than that in bulk Fe; the coupling between Fe atoms remained ferromagnetic and is insensitive to the thickness …

Structure And Stability Of Co-N(Pyridine)(M)(-) Clusters: Absence Of Metal Inserted Structures, B. Douglas Edmonds, A. K. Kandalam, S. N. Khanna, X. Li, A. Grubisic, I. Khanna, K. H. Bowen

Physics Publications

A synergistic approach combining the experimental photoelectron spectroscopy and theoretical electronic structure studies is used to probe the geometrical structure and the spin magnetic moment of Con(pyridine)−m clusters. It is predicted that the ground state of Co(pyridine)− is a structure where the Co atom is inserted in a CH bond. However, the insertion is marked by a barrier of 0.33eV that is not overcome under the existing experimental conditions resulting in the formation of a structure where Co occupies a site above the pyridine plane. For Co2(pyridine)−, a ground-state structure is predicted in which the Co2 diametric moiety is inserted …

Hydrogen Storage And The 18-Electron Rule, Boggavarapu Kiran, Anil K. Kandalam, Puru Jena

Physics Publications

We show that the 18-electron rule can be used to design new organometallic systems that can store hydrogen with large gravimetric density. In particular, Ti containing organic molecules such as C4H4, C5H5, and C8H8 can store up to 9wt% hydrogen, which meets the Department of Energy target for the year 2015. More importantly, hydrogen in these materials is stored in molecular form with an average binding energy of about 0.55eV∕H2 molecule, which is ideal for fast kinetics. Using molecular orbitals we have analyzed the maximum number of H2 molecules that can be adsorbed as well as the nature of their …

Gold As Hydrogen: Structural And Electronic Properties And Chemical Bonding In Si3au3+/0/- And Comparisons To Si3h3+/0/-, Boggavarapu Kiran, Xi Li, Hua-Jin Zhai, Lai-Sheng Wang

Physics Publications

A single Au atom has been shown to behave like H in its bonding to Si in several mono- and disilicon gold clusters. In the current work, we investigate the Au∕H analogy in trisilicon gold clusters, Si3Au+∕0∕−3. Photoelectron spectroscopy and density functional calculations are combined to examine the geometric and electronic structure of Si3Au−3. We find that there are three isomers competing for the ground state of Si3Au−3 as is the case for Si3H−3. Extensive structural searches show that the potential energy surfaces of the trisilicon gold clusters (Si3Au−3, Si3Au3, and Si3Au+3) are similar to those of the corresponding silicon …

Hybrid Solar Cells From Water-Soluble Polymers, James T. Mcleskey Jr., Qiquan Qiao

Mechanical and Nuclear Engineering Publications

We report on the use of a water-soluble, light-absorbing polythiophene polymer to fabricate novel photovoltaic devices. The polymer is a water-soluble thiophene known as sodium poly[2-(3-thienyl)-ethoxy-4-butylsulfonate] or PTEBS. The intention is to take advantage of the properties of conjugated polymers (flexible, tunable, and easy to process) and incorporate the additional benefits of water solubility (easily controlled evaporation rates and environmentally friendly). The PTEBS polythiophene has shown significant photovoltaic response and has been found to be effective for making solar cells. To date, solar cells in three different configurations have been produced: titanium dioxide (TiO2) bilayer cells, TiO2 bulk heterojunction solar …

Strong Suppression Of The Yellow Luminescence In C-Doped Gan In Air Ambient, Michael A. Reshchikov

Physics Publications

The authors observed a drastic reduction of the yellow luminescence (YL) intensity in carbon-doped semi-insulating GaN in air or oxygen ambient as compared to the intensity in vacuum. The YL intensity dropped about 300 times while the exciton emission remained almost unchanged. The authors assume that the donor-acceptor-pair transitions involving a gallium vacancy complex in a thin near-surface region cause the strong YL. Oxygen molecules or ions induce the surface states acting as a very efficient channel of nonradiative recombination. The results indicate that carbon may not be involved in the acceptor responsible for the YL band in GaN:C.

Midinfrared Intersubband Absorption In Znxcd1−Xse/Znx′Cdy′Mg1−X′−Y′Se Multiple Quantum Well Structures, H. Lu, A. Shen, M. C. Tamargo, C. Y. Song, H. C. Liu, S. K. Zhang, R. R. Alfano, M. Muñoz

Physics Publications

The authors report the observation of intersubband absorption in ZnxCd(1−x)Se/Znx′Cdy′Mg(1−x′−y′)Semultiple quantum wells. Lattice-matched samples were grown by molecular beam epitaxy on InP (001) substrates. Photoluminescence measurements indicate that the samples have excellent material quality. The peak absorption wavelengths measured by Fourier transform infrared spectroscopy are 3.99 and 5.35μm for two samples with ZnxCd(1−x)Se well widths of 28 and 42Å, respectively. These values fall within the 3–5μm wavelength range, which is of interest for midinfrared intersubband devices, such as quantum cascade lasers and quantum well infrared photodetectors. Their experimental results fit well with theoretical predictions based on the envelope function approximation. …

Determination Of Acceptor Concentration In Gan From Photoluminescence, Michael A. Reshchikov

Physics Publications

The concentration of the acceptor responsible for the yellow luminescence (YL) band at about 2.2eV in GaN is determined from photoluminescence. The YL band intensity increases linearly with excitation power density and partially saturates above some critical value. The dependence is quantitatively described within a phenomenological model accounting for recombination statistics in GaN layer and saturation of acceptors with photogenerated holes. The incomplete saturation of the YL intensity at high excitation intensities is explained by gradual saturation of acceptors at different distances from the sample surface. The identity of deep and shallow acceptors in GaN is discussed.

Lactate Versus Non-Lactate Metabolic Acidosis: A Retrospective Outcome Evaluation Of Critically Ill Patients, Kyle J. Gunnerson, Melissa Saul, Shui He, John A. Kellum

Anesthesiology Publications

Introduction

Acid–base abnormalities are common in the intensive care unit (ICU). Differences in outcome exist between respiratory and metabolic acidosis in similar pH ranges. Some forms of metabolic acidosis (for example, lactate) seem to have worse outcomes than others (for example, chloride). The relative incidence of each type of disorder is unknown. We therefore designed this study to determine the nature and clinical significance of metabolic acidosis in critically ill patients.

Methods

An observational, cohort study of critically ill patients was performed in a tertiary care hospital. Critically ill patients were selected on the clinical suspicion of the presence of …

Survival Analysis Of Complete Veneer Crowns Vs. Multisurface Restorations: A Dental School Patient Population, Charles E. Janus, John W. Unger, Al M. Best

Prosthodontics Publications

The purpose of this study was to compare the longevity of crowns versus large multisurface restorations in posterior teeth. The investigation used the treatment database at Virginia Commonwealth University School of Dentistry. The inclusion criteria for the final data set used for analysis were: only one restored tooth per patient, premolars with three or more restored surfaces, molars with four or more restored surfaces, molars and premolars restored with complete veneer metal crowns, or crowns veneered with metal and porcelain. The Kaplan-Meier approach was used to visualize the survival curves, and the Cox proportional hazards model was used for analysis …

Normal And Inverse Spin-Valve Effect In Organic Semiconductor Nanowires And The Background Monotonic Magnetoresistance, Sandipan Pramanik, Supriyo Bandyopadhyay, Kalyan Garre, Marc Cahay

Electrical and Computer Engineering Publications

We have observed both peaks and troughs in the magnetoresistance of organic nanowires consisting of three layers—cobalt, 8-hydroxy-quinolinolato aluminum (Alq3), and nickel. They always occur between the coercive fields of the ferromagnetic layers, and we attribute them to the normal and inverse spin-valve effect. The latter is caused by resonant tunneling through localized impurity states in the organic material. Peaks are always found to be accompanied by a positive monotonic background magnetoresistance, while troughs are accompanied by a negative monotonic background magnetoresistance. This curious correlation suggests that the background magnetoresistance, whose origin has hitherto remained unexplained, is probably caused by …

Organic Anion And Cation Transporter Expression And Function During Embryonic Kidney Development And In Organ Culture Model Systems, Douglas H. Sweet, Satish A. Eraly, Kevin T. Bush, Sanjay K. Nigam

Pharmaceutics Publications

Background

Organic anion and cation transporters (OATs, OCTs and OCTNs) mediate the proximal tubular secretion of numerous clinically important compounds, including various commonly prescribed pharmaceuticals. Here, we examine the ontogeny of these transporters in rat embryonic kidney in detail, both in vivo and in two in vitro organ culture models of kidney development, whole embryonic kidney (WEK) culture and culture of induced metanephric mesenchyme (MM).

Methods

We used QPCR to determine expression levels of transporter genes in rat embryonic kidneys on each day of gestation from ed13 to ed18, in induced and un-induced MM, and on each day of one …

Comparison Of Severity Of Illness Scoring Systems For Patients With Nosocomial Bloodstream Infection Due To Pseudomonas Aeruginosa, Alexandre R. Marra, Gonzalo M. L. Bearman, Richard P. Wenzel, Michael B. Edmond

Internal Medicine Publications

Background

Several acute illness severity scores have been proposed for evaluating patients on admission to intensive care units but these have not been compared for patients with nosocomial bloodstream infection (nBSI). We compared three severity of illness scoring systems for predicting mortality in patients with nBSI due to Pseudomonas aeruginosa.

Methods

We performed a historical cohort study on 63 adults in intensive care units with P. aeruginosamonomicrobial nBSI.

Results

The Acute Physiology, Age, Chronic Health Evaluation II (APACHE II), Sequential Organ Failure Assessment (SOFA), and Simplified Acute Physiologic Score (SAPS II), were calculated daily from 2 days prior …

Acute Brochitis, Richard P. Wenzel, Alpha A. Fowler Iii

Internal Medicine Publications

A 40-year-old man with no underlying lung disease has a 7-day history of mild shortness of breath with exertion, as well as cough that is now productive of purulent sputum. He reports no paroxysms of cough and no contact with ill persons in his community. He does not appear to be in distress. His temperature is 37°C, his pulse 84 beats per minute, and his respiratory rate 17 breaths per minute. On auscultation of the lungs, no rales are heard; scattered wheezes are heard in the lung bases. How should he be evaluated and treated?

Summary and Recommendations

The patient …

Accuracy And Consistency Of Radiographic Interpretation Among Clinical Instructors Using Two Viewing Systems, Sharon K. Lanning, Al M. Best, Henry J. Temple, Philip S. Richards, Alllison Carey, Laurie K. Mccauley

Periodontics Publications

Accurate and consistent radiographic interpretation among clinical instructors is needed for assessment of teaching, student performance, and patient care. The purpose of this investigation was to determine if the method of radiographic viewing affects accuracy and consistency of instructors’ determinations of bone loss. Forty-one clinicians who provide instruction in a dental school clinical teaching program (including periodontists, general dentists, periodontal graduate students, and dental hygienists) quantified bone loss for up to twenty-five teeth into four descriptive categories using a view box for plain film viewing or a projection system for digitized image viewing. Ratings were compared to the correct category …

Empirical Validation Of The S-Score Algorithm In The Analysis Of Gene Expression Data, Richard Ellis Kennedy, Kellie J. Archer, Michael F. Miles

Biostatistics Publications

Background Current methods of analyzing Affymetrix GeneChip® microarray data require the estimation of probe set expression summaries, followed by application of statistical tests to determine which genes are differentially expressed. The S-Score algorithm described by Zhang and colleagues is an alternative method that allows tests of hypotheses directly from probe level data. It is based on an error model in which the detected signal is proportional to the probe pair signal for highly expressed genes, but approaches a background level (rather than 0) for genes with low levels of expression. This model is used to calculate relative change in probe …

Deficiency Of Cartilage-Associated Protein In Recessive Lethal Osteogenesis Imperfecta, Aileen M. Barnes, Weizhong Chang, Roy Morello, Wayne A. Cabral, Maryann Weis, David R. Eyre, Sergey Leikin, Elena Makareeva, Natalia Kuznetsova, Thomas E. Uveges, Aarthi Ashok, Armando W. Flor, John J. Mulvihill, Patrick L. Wilson, Usha T. Sundaram, Brendan Lee, Joan C. Marini

VCU Health Publications

Classic osteogenesis imperfecta, an autosomal dominant disorder associated with osteoporosis and bone fragility, is caused by mutations in the genes for type I collagen. A recessive form of the disorder has long been suspected. Since the loss of cartilage-associated protein (CRTAP), which is required for post-translational prolyl 3-hydroxylation of collagen, causes severe osteoporosis in mice, we investigated whether CRTAP deficiency is associated with recessive osteogenesis imperfecta. Three of 10 children with lethal or severe osteogenesis imperfecta, who did not have a primary collagen defect yet had excess post-translational modification of collagen, were found to have a recessive condition resulting in …

Subpicosecond Time-Resolved Raman Studies Of Field-Induced Transient Transport In An Inxga1−Xas-Based P-I-N Semiconductor Nanostructure, K. T. Tsen, Juliann G. Kiang, D. K. Ferry, Hadis Morkoç

Physics Publications

Electron transient transport in an InxGa1−xAs-based (x=0.53) p-i-nnanostructure under the application of an electric field has been studied by time-resolvedRaman spectroscopy on a subpicosecond time scale and at T=300K. The experimental results reveal the time evolution of the electron distribution function and electron drift velocity with subpicosecond time resolution. These experimental results are compared with those of both InP-based and GaAs-based p-i-nnanostructures and provide a consistent understanding and better insight of electron transient transport phenomena in semiconductors.

Clustering Of Cr In Gan Nanotubes And The Onset Of Ferrimagnetic Order, Q. Wang, Q. Sun, Puru Jena, Y. Kawazoe

Physics Publications

A comprehensive theoretical study of the structure and magnetic properties of Cr-doped GaN nanotubes yields some interesting and unexpected results: (1) A single wall GaN nanotube constructed from the GaN wurtzite crystal relaxes to a carbon-like zigzag SWNT structure and remains stable at 300K, while a multiwall GaN nanotube retains its original wurtzite form. (2) Cr atoms prefer to form clusters and the underlying magnetism depends on the degree of clustering. (3) The coupling between two Cr atoms mediated by the neighboring N is ferromagnetic, but changes to ferrimagnetic as the cluster grows. These results are based on spin polarized …