Language Modernization vs. Linguistic Protectionism

ERIC Educational Resources Information Center

Prifti, Erida

2009-01-01

Since 1991, when the fiercest of all Communist isolations broke and the borders to the world were finally opened, the Albanian language has been undergoing significant changes in its lexicon and, at a certain measure, in its structure. Numerous concepts have found their way into the Albanian knowledge base before an Albanian word was ever found to…

Effects of Irradiation on Albite's Chemical Durability.

PubMed

Hsiao, Yi-Hsuan; La Plante, Erika Callagon; Krishnan, N M Anoop; Le Pape, Yann; Neithalath, Narayanan; Bauchy, Mathieu; Sant, Gaurav

2017-10-19

Albite (NaAlSi 3 O 8 ), a framework silicate of the plagioclase feldspar family and a common constituent of felsic rocks, is often present in the siliceous mineral aggregates that compose concrete. When exposed to radiation (e.g., in the form of neutrons) in nuclear power plants, the crystal structure of albite can undergo significant alterations. These alterations may degrade its chemical durability. Indeed, careful examinations of Ar + -implanted albite carried out using Fourier transform infrared spectroscopy (FTIR) and molecular dynamics simulations show that albite's crystal structure, upon irradiation, undergoes progressive disordering, resulting in an expansion in its molar volume (i.e., a reduction of density) and a reduction in the connectivity of its atomic network. This loss of network connectivity (i.e., rigidity) results in an enhancement of the aqueous dissolution rate of albite-measured using vertical scanning interferometry (VSI) in alkaline environments-by a factor of 20. This enhancement in the dissolution rate (i.e., reduction in chemical durability) of albite following irradiation has significant impacts on the durability of felsic rocks and of concrete containing them upon their exposure to radiation in nuclear power plant (NPP) environments.

Optomechanics of two- and three-dimensional soft photonic crystals

NASA Astrophysics Data System (ADS)

Krishnan, Dwarak

Soft photonic crystals are a class of periodic dielectric structures that undergo highly nonlinear deformation due to strain or other external stimulus such as temperature, pH etc. This can in turn dramatically affect optical properties such as light transmittance. Moreover certain classes of lithographically fabricated structures undergo some structural distortion due to the effects of processing, eventually affecting the optical properties of the final photonic crystal. In this work, we study the deformation mechanics of soft photonic crystal structures using realistic physics-based models and leverage that understanding to explain the optomechanics of actual 2-D and 3-D soft photonic crystals undergoing similar symmetry breaking nonlinear deformations. We first study the optomechanics of two classes of 3-D soft photonic crystals: (1) hydrogel and (2) elastomer based material systems. The hydrogel based inverse face-centered-cubic structure undergoes swelling with change in pH of the surrounding fluid. The inverse structure is a network of bulky domains with thin ligament-like connections, and it undergoes a pattern transformation from FCC to L11 as a result of swelling. A continuum scale poroelasticity based coupled fluid-diffusion FEM model is developed to accurately predict this mechanical behavior. Light transmittance simulation results qualitatively explain the experimentally observed trends in the optical behavior with pH change. The elastomer based, lithographically fabricated material experiences shrinkage induced distortion upon processing. This behavior is modeled using FEM with the material represented by a neo-Hookean constitutive law. The light transmittance calculations for normal incidence are carried out using the transfer matrix method and a good comparison is obtained for the positions of first and second order reflectance peaks. A unit cell based approach is taken to compute the photonic bandstructure to estimate light propagation through the structure for other angles of light incidence. To obtain a detailed picture of the change in optical properties due to a pattern transformation, we study simple 2-D elastomer photonic crystals which undergo an interesting structural pattern transformation from simple circular holes to alternately oriented ellipses in a square lattice due to uniaxial compression. The incident light does not have any effect on the properties of the elastomer material. A decomposition of the deformation gradient quickly shows that the pattern transformation is induced by alternating rotations of the interstitial regions and the bending of interconnecting ligaments. Numerical simulations of light transmittance using vector element based FEM analysis of Maxwells equations shows changes in the light energy localization within the material especially in the high energy/low wavelength regions of the spectra. Additionally, with bandstructure calculations on a unit cell of the structure, the optomechanical behavior is completely explained. Finally, computational evidence is provided for a hypothetical 2-D photonic crystal made of a light-sensitive material, which undergoes a structural pattern transformation primarily due to the effect of incident light. The model takes into account the order kinetics of optically induced isomerization (of trans to cis configuration) in the azobenzene-liquid crystal elastomer to compute the transformational strain. This strain, in turn, deforms the structure and hence changes its periodicity and dielectric properties and thus affects the manner in which light gets localized within the material system. This consequently changes the profile of the imposed transformational strain on the deformed structure. The macroscopic strain history shows that prior to the mechanical instability that causes the pattern transformation, there is a period of structural relaxation which initiates the pattern transformation. After the symmetry breaking pattern transformation, the photonic bandstructure is altered significantly. Light does not get localized in the spot regions anymore and stress relaxation dominates. Due to this, the compressive macroscopic strain of the pattern transformed structure starts to decrease indicating a possible cyclical behavior.

Quantitative Mass Spectrometry Reveals Changes in Histone H2B Variants as Cells Undergo Inorganic Arsenic-Mediated Cellular Transformation*

PubMed Central

Rea, Matthew; Jiang, Tingting; Eleazer, Rebekah; Eckstein, Meredith; Marshall, Alan G.; Fondufe-Mittendorf, Yvonne N.

2016-01-01

Exposure to inorganic arsenic, a ubiquitous environmental toxic metalloid, leads to carcinogenesis. However, the mechanism is unknown. Several studies have shown that inorganic arsenic exposure alters specific gene expression patterns, possibly through alterations in chromatin structure. While most studies on understanding the mechanism of chromatin-mediated gene regulation have focused on histone post-translational modifications, the role of histone variants remains largely unknown. Incorporation of histone variants alters the functional properties of chromatin. To understand the global dynamics of chromatin structure and function in arsenic-mediated carcinogenesis, analysis of the histone variants incorporated into the nucleosome and their covalent modifications is required. Here we report the first global mass spectrometric analysis of histone H2B variants as cells undergo arsenic-mediated epithelial to mesenchymal transition. We used electron capture dissociation-based top-down tandem mass spectrometry analysis validated with quantitative reverse transcription real-time polymerase chain reaction to identify changes in the expression levels of H2B variants in inorganic arsenic-mediated epithelial-mesenchymal transition. We identified changes in the expression levels of specific histone H2B variants in two cell types, which are dependent on dose and length of exposure of inorganic arsenic. In particular, we found increases in H2B variants H2B1H/1K/1C/1J/1O and H2B2E/2F, and significant decreases in H2B1N/1D/1B as cells undergo inorganic arsenic-mediated epithelial-mesenchymal transition. The analysis of these histone variants provides a first step toward an understanding of the functional significance of the diversity of histone structures, especially in inorganic arsenic-mediated gene expression and carcinogenesis. PMID:27169413

Strongly Modulated Friction of a Film-Terminated Ridge-Channel Structure.

PubMed

He, Zhenping; Hui, Chung-Yuen; Levrard, Benjamin; Bai, Ying; Jagota, Anand

2016-05-26

Natural contacting surfaces have remarkable surface mechanical properties, which has led to the development of bioinspired surface structures using rubbery materials with strongly enhanced adhesion and static friction. However, sliding friction of structured rubbery surfaces is almost always significantly lower than that of a flat control, often due to significant loss of contact. Here we show that a film-terminated ridge-channel structure can strongly enhance sliding friction. We show that with properly chosen materials and geometrical parameters the near surface structure undergoes mechanical instabilities along with complex folding and sliding of internal interfaces, which is responsible for the enhancement of sliding friction. Because this structure shows no enhancement of adhesion under normal indentation by a sphere, it breaks the connection between energy loss during normal and shear loading. This makes it potentially interesting in many applications, for instance in tires, where one wishes to minimize rolling resistance (normal loading) while maximizing sliding friction (shear loading).

Tensions in Higher Education Leadership: Towards a Multi-Level Model of Leadership Practice

ERIC Educational Resources Information Center

Bolden, Richard; Petrov, Georgy; Gosling, Jonathan

2008-01-01

UK higher education is undergoing a period of significant change that generates a series of tensions and difficulties for universities and university leaders. This paper explores these tensions through analysis of findings from a study comprising 152 semi-structured face-to-face interviews in 12 UK universities. Building on from theories of…

Learning to Teach Primary Geography in the Context of School Placement: Lessons from an All-Ireland Study

ERIC Educational Resources Information Center

Dolan, Anne M.; Waldron, Fionnuala; Pike, Susan; Greenwood, Richard

2016-01-01

Teaching education is Ireland is currently undergoing significant structural and conceptual changes. School placement is at the centre of these reforms. This article reports the findings of an all-Ireland study which investigates student teachers' experiences of teaching geography during their school placements. Based on data collected from…

Analysis of the 918th Contracting Battalion and 410th Contracting Support Brigade Utilizing the Contract Management Maturity Model

DTIC Science & Technology

2015-12-01

organizational structure of Army contracting and the changes to that organization under the MICC 2025 plan. We then describe the organizations where we... organizational change . Portal: Libraries and the Academy, 4(3), 345–361. McFall, T. (2015). 918th CBN/MICC-FC organizational overview [PowerPoint slides...Installation Contracting Command (MICC) are undergoing a significant change in structure known as MICC 2025. In order to gauge the effectiveness of this

Mycobacterium tuberculosis acyl carrier protein synthase adopts two different pH-dependent structural conformations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gokulan, Kuppan; Aggarwal, Anup; Shipman, Lance

2011-09-20

The crystal structures of acyl carrier protein synthase (AcpS) from Mycobacterium tuberculosis (Mtb) and Corynebacterium ammoniagenes determined at pH 5.3 and pH 6.5, respectively, are reported. Comparison of the Mtb apo-AcpS structure with the recently reported structure of the Mtb AcpS-ADP complex revealed that AcpS adopts two different conformations: the orthorhombic and trigonal space-group structures show structural differences in the {alpha}2 helix and in the conformation of the {alpha}3-{alpha}4 connecting loop, which is in a closed conformation. The apo-AcpS structure shows electron density for the entire model and was obtained at lower pH values (4.4-6.0). In contrast, at a highermore » pH value (6.5) AcpS undergoes significant conformational changes, resulting in disordered regions that show no electron density in the AcpS model. The solved structures also reveal that C. ammoniagenes AcpS undergoes structural rearrangement in two regions, similar to the recently reported Mtb AcpS-ADP complex structure. In vitro reconstitution experiments show that AcpS has a higher post-translational modification activity between pH 4.4 and 6.0 than at pH values above 6.5, where the activity drops owing to the change in conformation. The results show that apo-AcpS and AcpS-ADP adopt different conformations depending upon the pH conditions of the crystallization solution.« less

Formation of an Anti-Core–Shell Structure in Layered Oxide Cathodes for Li-Ion Batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Hanlei; Omenya, Fredrick; Whittingham, M. Stanley

The layered → rock-salt phase transformation in the layered dioxide cathodes for Li-ion batteries is believed to result in a “core-shell” structure of the primary particles, in which the core region maintains as the layered phase while the surface region undergoes the phase transformation to the rock-salt phase. Using transmission electron microscopy, here we demonstrate the formation of an “anti-core-shell” structure in cycled primary particles with a formula of LiNi0.80Co0.15Al0.05O2, in which the surface and subsurface regions remain as the layered structure while the rock-salt phase forms as domains in the bulk with a thin layer of the spinel phasemore » between the rock-salt core and the skin of the layered phase. Formation of this anti-core-shell structure is attributed to the oxygen loss at the surface that drives the migration of oxygen from the bulk to the surface, thereby resulting in localized areas of significantly reduced oxygen levels in the bulk of the particle, which subsequently undergoes the phase transformation to the rock-salt domains. The formation of the anti-core-shell rock-salt domains is responsible for the reduced capacity, discharge voltage and ionic conductivity in cycled cathode.« less

LORS. Learning Oriented Reality Structure...Or How to Keep Your Sanity and Have Fun Besides in All Those Crazy Meetings!

ERIC Educational Resources Information Center

Hollis, Joseph W.; And Others

The LORS technique is a combination of several techniques such as role projection, simulation, psychodrama, feedback, value clarification, role reversal, dramatization, decision making, process analysis, and others. The significant difference is that, when the techniques are used together, each often undergoes changes to the point that the effect…

Mythorealistic Concept of "Beautiful Lady" in the Structure of the Author's Identity (Based on the Diaries of Alexander Blok)

ERIC Educational Resources Information Center

Minets, Diana

2016-01-01

The present paper deals with the diaries of Alexander Blok dated 1901-1921 reflecting the process of the writer's self-identification. During 20 years under the influence of various social and cultural situations Blok's "Self-Conception" is undergoing significant changes. The vector of these changes shows the complicated evolution of the…

46 CFR 176.600 - Drydock and internal structural examination intervals.

Code of Federal Regulations, 2010 CFR

2010-10-01

... States port, it must undergo the required examination before sailing. (c) If your vessel is not operated... exclusively by divers, the vessel must undergo two alternate hull exams and two internal structural exams within any five-year period. If a vessel completes a satisfactory alternate hull exam, with the...

KENNEDY SPACE CENTER, FLA. - Launch Pad 39A undergoes sandblasting of its metal structures and surfaces. Routine maintenance includes sandblasting and repainting as preventive means to minimize corrosion.

NASA Image and Video Library

2003-09-12

KENNEDY SPACE CENTER, FLA. - Launch Pad 39A undergoes sandblasting of its metal structures and surfaces. Routine maintenance includes sandblasting and repainting as preventive means to minimize corrosion.

Relation of pulmonary vessel size to transfer factor in subjects with airflow obstruction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Musk, A.W.

In a group of 61 consecutive patients undergoing assessment of airflow obstruction, a significant linear relation was demonstrated between measurements of the diameter of the midzonal pulmonary vessels on the plain chest radiographs and transfer factor (diffusing capacity for carbon monoxide) (r = 0.46, p < 0.001). Since reduction in transfer factor has been shown to relate to structural emphysema, reduction in midzone vessel caliber implies the same. However, in the individual patient neither the transfer factor nor structural emphysema can be reliably predicted from midzone vessel diameters alone.

Modifications of the Mesoscopic Structure of Cellulose in Paper Degradation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Missori, Mauro; Bicchieri, Marina; Mondelli, Claudia

2006-12-08

Paper is the main component of a huge quantity of cultural heritage. It is primarily composed of cellulose that undergoes significant degradation with the passage of time. By using small angle neutron scattering (SANS), we investigated cellulose's supramolecular structure, which allows access to degradation agents, in ancient and modern samples. For the first time, SANS data were interpreted in terms of water-filled pores, with their sizes increasing from 1.61 nm up to 1.97 nm in natural and artificially aged papers. The protective effect of gelatine sizing was also observed.

Modifications of the Mesoscopic Structure of Cellulose in Paper Degradation

NASA Astrophysics Data System (ADS)

Missori, Mauro; Mondelli, Claudia; de Spirito, Marco; Castellano, Carlo; Bicchieri, Marina; Schweins, Ralf; Arcovito, Giuseppe; Papi, Massimiliano; Castellano, Agostina Congiu

2006-12-01

Paper is the main component of a huge quantity of cultural heritage. It is primarily composed of cellulose that undergoes significant degradation with the passage of time. By using small angle neutron scattering (SANS), we investigated cellulose’s supramolecular structure, which allows access to degradation agents, in ancient and modern samples. For the first time, SANS data were interpreted in terms of water-filled pores, with their sizes increasing from 1.61 nm up to 1.97 nm in natural and artificially aged papers. The protective effect of gelatine sizing was also observed.

Investigation of the redox-dependent modulation of structure and dynamics in human cytochrome c.

PubMed

Imai, Mizue; Saio, Tomohide; Kumeta, Hiroyuki; Uchida, Takeshi; Inagaki, Fuyuhiko; Ishimori, Koichiro

2016-01-22

Redox-dependent changes in the structure and dynamics of human cytochrome c (Cyt c) were investigated by solution NMR. We found significant structural changes in several regions, including residues 23-28 (loop 3), which were further corroborated by chemical shift differences between the reduced and oxidized states of Cyt c. These differences are essential for discriminating redox states in Cyt c by cytochrome c oxidase (CcO) during electron transfer reactions. Carr-Purcell-Meiboom-Gill (CPMG) relaxation dispersion experiments identified that the region around His33 undergoes conformational exchanges on the μs-ms timescale, indicating significant redox-dependent structural changes. Because His33 is not part of the interaction site for CcO, our data suggest that the dynamic properties of the region, which is far from the interaction site for CcO, contribute to conformational changes during electron transfer to CcO. Copyright © 2015 Elsevier Inc. All rights reserved.

An unexpected twist in viral capsid maturation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gertsman, Ilya; Gan, Lu; Guttman, Miklos

2009-04-14

Lambda-like double-stranded (ds) DNA bacteriophage undergo massive conformational changes in their capsid shell during the packaging of their viral genomes. Capsid shells are complex organizations of hundreds of protein subunits that assemble into intricate quaternary complexes that ultimately are able to withstand over 50 atm of pressure during genome packaging. The extensive integration between subunits in capsids requires the formation of an intermediate complex, termed a procapsid, from which individual subunits can undergo the necessary refolding and structural rearrangements needed to transition to the more stable capsid. Although various mature capsids have been characterized at atomic resolution, no such procapsidmore » structure is available for a dsDNA virus or bacteriophage. Here we present a procapsid X-ray structure at 3.65 {angstrom} resolution, termed prohead II, of the lambda-like bacteriophage HK97, the mature capsid structure of which was previously solved to 3.44 {angstrom}. A comparison of the two largely different capsid forms has unveiled an unprecedented expansion mechanism that describes the transition. Crystallographic and hydrogen/deuterium exchange data presented here demonstrate that the subunit tertiary structures are significantly different between the two states, with twisting and bending motions occurring in both helical and -sheet regions. We also identified subunit interactions at each three-fold axis of the capsid that are maintained throughout maturation. The interactions sustain capsid integrity during subunit refolding and provide a fixed hinge from which subunits undergo rotational and translational motions during maturation. Previously published calorimetric data of a closely related bacteriophage, P22, showed that capsid maturation was an exothermic process that resulted in a release of 90 kJ mol{sup -1} of energy. We propose that the major tertiary changes presented in this study reveal a structural basis for an exothermic maturation process probably present in many dsDNA bacteriophage and possibly viruses such as herpesvirus, which share the HK97 subunit fold.« less

Isolated Human Pulmonary Artery Structure and Function Pre- and Post-Cardiopulmonary Bypass Surgery.

PubMed

Dora, Kim A; Stanley, Christopher P; Al Jaaly, Emad; Fiorentino, Francesca; Ascione, Raimondo; Reeves, Barnaby C; Angelini, Gianni D

2016-02-23

Pulmonary dysfunction is a known complication after cardiac surgery using cardiopulmonary bypass, ranging from subclinical functional changes to prolonged postoperative ventilation, acute lung injury, and acute respiratory distress syndrome. Whether human pulmonary arterial function is compromised is unknown. The aim of the present study was to compare the structure and function of isolated and cannulated human pulmonary arteries obtained from lung biopsies after the chest was opened (pre-cardiopulmonary bypass) to those obtained at the end of cardiopulmonary bypass (post-cardiopulmonary bypass) from patients undergoing coronary artery bypass graft surgery. Pre- and post-cardiopulmonary bypass lung biopsies were received from 12 patients undergoing elective surgery. Intralobular small arteries were dissected, cannulated, pressurized, and imaged using confocal microscopy. Functionally, the thromboxane mimetic U46619 produced concentration-dependent vasoconstriction in 100% and 75% of pre- and post-cardiopulmonary bypass arteries, respectively. The endothelium-dependent agonist bradykinin stimulated vasodilation in 45% and 33% of arteries pre- and post-cardiopulmonary bypass, respectively. Structurally, in most arteries smooth muscle cells aligned circumferentially; live cell viability revealed that although 100% of smooth muscle and 90% of endothelial cells from pre-cardiopulmonary bypass biopsies had intact membranes and were considered viable, only 60% and 58%, respectively, were viable from post-cardiopulmonary bypass biopsies. We successfully investigated isolated pulmonary artery structure and function in fresh lung biopsies from patients undergoing heart surgery. Pulmonary artery contractile tone and endothelium-dependent dilation were significantly reduced in post-cardiopulmonary bypass biopsies. The decreased functional responses were associated with reduced cell viability. URL: http://www.isrctn.com/ISRCTN34428459. Unique identifier: ISRCTN 34428459. © 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

AFLP genome scan in the black rat (Rattus rattus) from Madagascar: detecting genetic markers undergoing plague-mediated selection.

PubMed

Tollenaere, C; Duplantier, J-M; Rahalison, L; Ranjalahy, M; Brouat, C

2011-03-01

The black rat (Rattus rattus) is the main reservoir of plague (Yersinia pestis infection) in Madagascar's rural zones. Black rats are highly resistant to plague within the plague focus (central highland), whereas they are susceptible where the disease is absent (low altitude zone). To better understand plague wildlife circulation and host evolution in response to a highly virulent pathogen, we attempted to determine genetic markers associated with plague resistance in this species. To this purpose, we combined a population genomics approach and an association study, both performed on 249 AFLP markers, in Malagasy R. rattus. Simulated distributions of genetic differentiation were compared to observed data in four independent pairs, each consisting of one population from the plague focus and one from the plague-free zone. We found 22 loci (9% of 249) with higher differentiation in at least two independent population pairs or with combining P-values over the four pairs significant. Among the 22 outlier loci, 16 presented significant association with plague zone (plague focus vs. plague-free zone). Population genetic structure inferred from outlier loci was structured by plague zone, whereas the neutral loci dataset revealed structure by geography (eastern vs. western populations). A phenotype association study revealed that two of the 22 loci were significantly associated with differentiation between dying and surviving rats following experimental plague challenge. The 22 outlier loci identified in this study may undergo plague selective pressure either directly or more probably indirectly due to hitchhiking with selected loci. © 2010 Blackwell Publishing Ltd.

Structure of northern spotted owl nest stands and their historical conditions on the eastern slope of the Pacific Northwest Cascades, USA.

Treesearch

Richard Everett; D. Schellhaas; D. Spurbeck; [and others].

1997-01-01

The northern spotted (Strix occidentalis caurina) uses a wide array of nesting habitat throughout its current range and successfully reproduces in a variety of stand types on the eastern slope of the Pacific Northwest Cascades. The species has the ability to utilize dynamic forest stands that continue to undergo significant changes in tree density...

Changes in the Golgi Apparatus of Neocortical and Hippocampal Neurons in the Hibernating Hamster.

PubMed

Antón-Fernández, Alejandro; León-Espinosa, Gonzalo; DeFelipe, Javier; Muñoz, Alberto

2015-01-01

Hibernating animals have been used as models to study several aspects of the plastic changes that occur in the metabolism and physiology of neurons. These models are also of interest in the study of Alzheimer's disease because the microtubule-associated protein tau is hyperphosphorylated during the hibernation state known as torpor, similar to the pretangle stage of Alzheimer's disease. Hibernating animals undergo torpor periods with drops in body temperature and metabolic rate, and a virtual cessation of neural activity. These processes are accompanied by morphological and neurochemical changes in neurons, which reverse a few hours after coming out of the torpor state. Since tau has been implicated in the structural regulation of the neuronal Golgi apparatus (GA) we have used Western Blot and immunocytochemistry to analyze whether the GA is modified in cortical neurons of the Syrian hamster at different hibernation stages. The results show that, during the hibernation cycle, the GA undergo important structural changes along with differential modifications in expression levels and distribution patterns of Golgi structural proteins. These changes were accompanied by significant transitory reductions in the volume and surface area of the GA elements during torpor and arousal stages as compared with euthermic animals.

Changes in the Golgi Apparatus of Neocortical and Hippocampal Neurons in the Hibernating Hamster

PubMed Central

Antón-Fernández, Alejandro; León-Espinosa, Gonzalo; DeFelipe, Javier; Muñoz, Alberto

2015-01-01

Hibernating animals have been used as models to study several aspects of the plastic changes that occur in the metabolism and physiology of neurons. These models are also of interest in the study of Alzheimer's disease because the microtubule-associated protein tau is hyperphosphorylated during the hibernation state known as torpor, similar to the pretangle stage of Alzheimer's disease. Hibernating animals undergo torpor periods with drops in body temperature and metabolic rate, and a virtual cessation of neural activity. These processes are accompanied by morphological and neurochemical changes in neurons, which reverse a few hours after coming out of the torpor state. Since tau has been implicated in the structural regulation of the neuronal Golgi apparatus (GA) we have used Western Blot and immunocytochemistry to analyze whether the GA is modified in cortical neurons of the Syrian hamster at different hibernation stages. The results show that, during the hibernation cycle, the GA undergo important structural changes along with differential modifications in expression levels and distribution patterns of Golgi structural proteins. These changes were accompanied by significant transitory reductions in the volume and surface area of the GA elements during torpor and arousal stages as compared with euthermic animals. PMID:26696838

Enhancing Raman signals through electromagnetic hot zones induced by magnetic dipole resonance of metal-free nanoparticles

NASA Astrophysics Data System (ADS)

Tseng, Yi-Chuan; Lee, Yang-Chun; Chang, Sih-Wei; Lin, Tzu-Yao; Ma, Dai-Liang; Lin, Bo-Cheng; Chen, Hsuen-Li

2017-11-01

In this study, we found that the large area of electromagnetic field hot zone induced through magnetic dipole resonance of metal-free structures can greatly enhance Raman scattering signals. The magnetic resonant nanocavities, based on high-refractive-index silicon nanoparticles (SiNPs), were designed to resonate at the wavelength of the excitation laser of the Raman system. The well-dispersed SiNPs that were not closely packed displayed significant magnetic dipole resonance and gave a Raman enhancement per unit volume of 59 347. The hot zones of intense electric field were generated not only within the nonmetallic NPs but also around them, even within the underlying substrate. We observed experimentally that gallium nitride (GaN) and silicon carbide (SiC) surfaces presenting very few SiNPs (coverage: <0.3%) could display significantly enhanced (>50%) Raman signals. In contrast, the Raman signals of the underlying substrates were not enhanced by gold nanoparticles (AuNPs), even though these NPs displayed a localized surface plasmon resonance (LSPR) phenomenon. A comparison of the areas of the electric field hot zones (E 2 > 10) generated by SiNPs undergoing magnetic dipole resonance with the electric field hot spots (E 2 > 10) generated by AuNPs undergoing LSPR revealed that the former was approximately 70 times that of the latter. More noteworthily, the electromagnetic field hot zone generated from the SiNP is able to extend into the surrounding and underlying media. Relative to metallic NPs undergoing LSPR, these nonmetallic NPs displaying magnetic dipole resonance were more effective at enhancing the Raman scattering signals from analytes that were underlying, or even far away from, them. This application of magnetic dipole resonance in metal-free structures appears to have great potential for use in developing next-generation techniques for Raman enhancement.

Single-particle tracking: applications to membrane dynamics.

PubMed

Saxton, M J; Jacobson, K

1997-01-01

Measurements of trajectories of individual proteins or lipids in the plasma membrane of cells show a variety of types of motion. Brownian motion is observed, but many of the particles undergo non-Brownian motion, including directed motion, confined motion, and anomalous diffusion. The variety of motion leads to significant effects on the kinetics of reactions among membrane-bound species and requires a revision of existing views of membrane structure and dynamics.

Alteration of the Cortical Actin Cytoskeleton Deregulates Ca2+ Signaling, Monospermic Fertilization, and Sperm Entry

PubMed Central

Puppo, A.; Chun, Jong T.; Gragnaniello, Giovanni; Garante, Ezio; Santella, Luigia

2008-01-01

Background When preparing for fertilization, oocytes undergo meiotic maturation during which structural changes occur in the endoplasmic reticulum (ER) that lead to a more efficient calcium response. During meiotic maturation and subsequent fertilization, the actin cytoskeleton also undergoes dramatic restructuring. We have recently observed that rearrangements of the actin cytoskeleton induced by actin-depolymerizing agents, or by actin-binding proteins, strongly modulate intracellular calcium (Ca2+) signals during the maturation process. However, the significance of the dynamic changes in F-actin within the fertilized egg has been largely unclear. Methodology/Principal Findings We have measured changes in intracellular Ca2+ signals and F-actin structures during fertilization. We also report the unexpected observation that the conventional antagonist of the InsP3 receptor, heparin, hyperpolymerizes the cortical actin cytoskeleton in postmeiotic eggs. Using heparin and other pharmacological agents that either hypo- or hyperpolymerize the cortical actin, we demonstrate that nearly all aspects of the fertilization process are profoundly affected by the dynamic restructuring of the egg cortical actin cytoskeleton. Conclusions/Significance Our findings identify important roles for subplasmalemmal actin fibers in the process of sperm-egg interaction and in the subsequent events related to fertilization: the generation of Ca2+ signals, sperm penetration, cortical granule exocytosis, and the block to polyspermy. PMID:18974786

Brainstem dose is associated with patient-reported acute fatigue in head and neck cancer radiation therapy.

PubMed

Ferris, Matthew J; Zhong, Jim; Switchenko, Jeffrey M; Higgins, Kristin A; Cassidy, Richard J; McDonald, Mark W; Eaton, Bree R; Patel, Kirtesh R; Steuer, Conor E; Baddour, H Michael; Miller, Andrew H; Bruner, Deborah W; Xiao, Canhua; Beitler, Jonathan J

2018-01-01

Radiation (RT) dose to the central nervous system (CNS) has been implicated as a contributor to treatment-related fatigue in head and neck cancer (HNC) patients undergoing radiation therapy (RT). This study evaluates the association of RT dose to CNS structures with patient-reported (PRO) fatigue scores in a population of HNC patients. At pre-RT (baseline), 6th week of RT, and 1-month post-RT time points, Multidimensional Fatigue Inventory (MFI-20) scores were prospectively obtained from 124 patients undergoing definitive treatment for HNC. Medulla, pons, midbrain, total brainstem, cerebellum, posterior fossa, and pituitary dosimetry were evaluated using summary statistics and dose-volume histograms, and associations with MFI-20 scores were analyzed. Maximum dose (Dmax) to the brainstem and medulla was significantly associated with MFI-20 scores at 6th week of RT and 1-month post-RT time points, after controlling for baseline scores (p<0.05). Each 1Gy increase in medulla Dmax resulted in an increase in total MFI-20 score over baseline of 0.30 (p=0.026), and 0.25 (p=0.037), at the 6th week of RT and 1-month post-RT, respectively. Each 1Gy increase in brainstem Dmax resulted in an increase in total MFI-20 score over baseline of 0.30 (p=0.027), and 0.25 (p=0.037) at the 6th week of RT, 1-month post-RT, respectively. Statistically significant associations were not found between dosimetry for the other CNS structures and MFI-20 scores. In this analysis of PRO fatigue scores from a population of patients undergoing definitive RT for HNC, maximum dose to the brainstem and medulla was associated with a significantly increased risk of acute patient fatigue. Copyright © 2017 Elsevier B.V. All rights reserved.

Mycobacterium tuberculosis acyl carrier protein synthase adopts two different pH-dependent structural conformations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gokulan, Kuppan; Aggarwal, Anup; Shipman, Lance

2011-07-01

Bacterial acyl carrier protein synthase plays an essential role in the synthesis of fatty acids, nonribosomal peptides and polyketides. In Mycobacterium tuberculosis, AcpS or group I phosphopentatheine transferase exhibits two different structural conformations depending upon the pH. The crystal structures of acyl carrier protein synthase (AcpS) from Mycobacterium tuberculosis (Mtb) and Corynebacterium ammoniagenes determined at pH 5.3 and pH 6.5, respectively, are reported. Comparison of the Mtb apo-AcpS structure with the recently reported structure of the Mtb AcpS–ADP complex revealed that AcpS adopts two different conformations: the orthorhombic and trigonal space-group structures show structural differences in the α2 helix andmore » in the conformation of the α3–α4 connecting loop, which is in a closed conformation. The apo-AcpS structure shows electron density for the entire model and was obtained at lower pH values (4.4–6.0). In contrast, at a higher pH value (6.5) AcpS undergoes significant conformational changes, resulting in disordered regions that show no electron density in the AcpS model. The solved structures also reveal that C. ammoniagenes AcpS undergoes structural rearrangement in two regions, similar to the recently reported Mtb AcpS–ADP complex structure. In vitro reconstitution experiments show that AcpS has a higher post-translational modification activity between pH 4.4 and 6.0 than at pH values above 6.5, where the activity drops owing to the change in conformation. The results show that apo-AcpS and AcpS–ADP adopt different conformations depending upon the pH conditions of the crystallization solution.« less

pH-Induced Stability Switching of the Bacteriophage HK97 Maturation Pathway

PubMed Central

2015-01-01

Many viruses undergo large-scale conformational changes during their life cycles. Blocking the transition from one stage of the life cycle to the next is an attractive strategy for the development of antiviral compounds. In this work, we have constructed an icosahedrally symmetric, low-energy pathway for the maturation transition of bacteriophage HK97. By conducting constant-pH molecular dynamics simulations on this pathway, we identify which residues are contributing most significantly to shifting the stability between the states along the pathway under differing pH conditions. We further analyze these data to establish the connection between critical residues and important structural motifs which undergo reorganization during maturation. We go on to show how DNA packaging can induce spontaneous reorganization of the capsid during maturation. PMID:24495192

Electronic doping of transition metal oxide perovskites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cammarata, Antonio, E-mail: cammaant@fel.cvut.cz; Rondinelli, James M.

2016-05-23

CaFeO{sub 3} is a prototypical negative charge transfer oxide that undergoes electronic metal-insulator transition concomitant with a dilation and contraction of nearly rigid octahedra. Altering the charge neutrality of the bulk system destroys the electronic transition, while the structure is significantly modified at high charge content. Using density functional theory simulations, we predict an alternative avenue to modulate the structure and the electronic transition in CaFeO{sub 3}. Charge distribution can be modulated using strain-rotation coupling and thin film engineering strategies, proposing themselves as a promising avenue for fine tuning electronic features in transition metal-oxide perovskites.

DSSTOX (DISTRIBUTED STRUCTURE-SEARCHABLE ...

EPA Pesticide Factsheets

Distributed Structure-Searchable Toxicity Database Network Major trends affecting public toxicity information resources have the potential to significantly alter the future of predictive toxicology. Chemical toxicity screening is undergoing shifts towards greater use of more fundamental information on gene/protein expression patterns and bioactivity and bioassay profiles, the latter generated with highthroughput screening technologies. Curated, systematically organized, and webaccessible toxicity and biological activity data in association with chemical structures, enabling the integration of diverse data information domains, will fuel the next frontier of advancement for QSAR (quantitative structure-activity relationship) and data mining technologies. The DSSTox project is supporting progress towards these goals on many fronts, promoting the use of formalized and structure-annotated toxicity data models, helping to interface these efforts with QSAR modelers, linking data from diverse sources, and creating a large, quality reviewed, central chemical structure information resource linked to various toxicity data sources

The influence of puberty on subcortical brain development.

PubMed

Goddings, Anne-Lise; Mills, Kathryn L; Clasen, Liv S; Giedd, Jay N; Viner, Russell M; Blakemore, Sarah-Jayne

2014-03-01

Puberty is characterized by hormonal, physical and psychological transformation. The human brain undergoes significant changes between childhood and adulthood, but little is known about how puberty influences its structural development. Using a longitudinal sample of 711 magnetic resonance imaging scans from 275 individuals aged 7-20years, we examined how subcortical brain regions change in relation to puberty. Our regions of interest included the amygdala, hippocampus and corpus striatum including the nucleus accumbens (NA), caudate, putamen and globus pallidus (GP). Pubertal development was significantly related to structural volume in all six regions in both sexes. Pubertal development and age had both independent and interactive influences on volume for the amygdala, hippocampus and putamen in both sexes, and the caudate in females. There was an interactive puberty-by-age effect on volume for the NA and GP in both sexes, and the caudate in males. These findings suggest a significant role for puberty in structural brain development. © 2013. Published by Elsevier Inc. All rights reserved.

The influence of puberty on subcortical brain development

PubMed Central

Goddings, Anne-Lise; Mills, Kathryn L.; Clasen, Liv S.; Giedd, Jay N.; Viner, Russell M.; Blakemore, Sarah-Jayne

2014-01-01

Puberty is characterized by hormonal, physical and psychological transformation. The human brain undergoes significant changes between childhood and adulthood, but little is known about how puberty influences its structural development. Using a longitudinal sample of 711 magnetic resonance imaging scans from 275 individuals aged 7–20 years, we examined how subcortical brain regions change in relation to puberty. Our regions of interest included the amygdala, hippocampus and corpus striatum including the nucleus accumbens (NA), caudate, putamen and globus pallidus (GP). Pubertal development was significantly related to structural volume in all six regions in both sexes. Pubertal development and age had both independent and interactive influences on volume for the amygdala, hippocampus and putamen in both sexes, and the caudate in females. There was an interactive puberty-by-age effect on volume for the NA and GP in both sexes, and the caudate in males. These findings suggest a significant role for puberty in structural brain development. PMID:24121203

Right heart chamber geometry and tricuspid annulus morphology in patients undergoing mitral valve repair with and without tricuspid valve annuloplasty.

PubMed

Tamborini, Gloria; Fusini, Laura; Muratori, Manuela; Gripari, Paola; Ghulam Ali, Sarah; Fiorentini, Cesare; Pepi, Mauro

2016-06-01

According to current recommendations, patients could benefit from tricuspid valve (TV) annuloplasty at the time mitral valve (MV) surgery if tricuspid regurgitation is severe or if tricuspid annulus (TA) dilatation is present. Therefore, an accurate pre-operative echocardiographic study is mandatory for left but also for right cardiac structures. Aims of this study are to assess right atrial (RA), right ventricular (RV) and TA geometry and function in patients undergoing MV repair without or with TV annuloplasty. We studied 103 patients undergoing MV surgery without (G1: 54 cases) or with (G2: 49 cases) concomitant TV annuloplasty and 40 healthy subjects (NL) as controls. RA, RV and TA were evaluated by three-dimensional (3D) transthoracic echocardiography. Comparing the pathological to the NL group, TA parameters and 3D right chamber volumes were significantly larger. RA and RV ejection fraction and TA% reduction were lower in pathological versus NL, and in G2 versus G1. In pathological patients, TA area positively correlated to systolic pulmonary pressure and negatively with RV and RA ejection fraction. Patients undergoing MV surgery and TV annuloplasty had an increased TA dimensions and a more advanced remodeling of right heart chambers probably reflecting an advanced stage of the disease.

Molecular Dynamics Studies of Structure and Functions of Water-Membrane Interfaces

NASA Technical Reports Server (NTRS)

Pohorille, Andrew; Wilson, Michael A.; DeVincenzi, Donald L. (Technical Monitor)

2001-01-01

A large number of essential cellular processes occur at the interfaces between water and membranes. The selectivity and dynamics of these processes are largely determined by the structural and electrical properties of the water-membrane interface. We investigate these properties by the molecular dynamics method. Over the time scales of the simulations, the membrane undergoes fluctuations described by the capillary wave model. These fluctuations produce occasional thinning defects in the membrane which provide effective pathways for passive transport of ions and small molecules across the membrane. Ions moving through the membrane markedly disrupt its structure and allow for significant water penetration into the membrane interior. Selectivity of transport, with respect to ionic charge, is determined by the interfacial electrostatic potential. Many small molecules. of potential significance in catalysis, bioenergetics and pharmacology, are shown to bind to the interface. The energetics and dynamics of this process will be discussed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coddington, Michael; Sciano, Damian; Fuller, Jason

The New York City boroughs of Brooklyn and Queens are undergoing a period of gentrification, infrastructure rebuilding, new construction, and load growth not experienced in decades. Significant numbers of residents are moving in, and structures that had been abandoned or were in disrepair are being refurbished and modernized to accommodate the burgeoning population. Homes, businesses, and industries are reviving areas long in decline, and Brooklyn's growth has made it the nation's fourth most populous city, according to the U.S. Census Bureau.

Structure Formation in Solutions of Rigid Polymers Undergoing a Phase Transition

DTIC Science & Technology

1987-04-01

cyclohexene dioxide (ERL-4206) - 10 g. nonenyl succinic anhydride (NSA) - 26 g. dimethyl amino ethanol ( DMAE ) - 0.4 g. After infiltration, short segments...existence of a significant number of defects within the individual microfibril. The presence of defects in the lateral packing of PBT chains is also suggested...of the D- and L- enantiomers yields a nematic phase. The ordered phases exhi- bit complex textures due to defects (disclinations) which depend on

Giant magnetostriction effect near onset of spin reorientation in MnBi

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, Y.; Ryan, P. J.; McGuire, Michael A.

In materials undergoing spontaneous symmetry breaking transitions, the emergence of multiple competing order parameters is pervasive. Employing in-field x-ray diffraction, we investigate the temperature and magnetic field dependence of the crystallographic structure of MnBi, elucidating the microscopic interplay between lattices and spin. The hexagonal phase of MnBi undergoes a spin reorientation transition (TSR), whereby the easy axis direction changes from the c axis to the basal plane. Across TSR, an abrupt symmetry change is accompanied by a clear sign change in the magnetostrictive coefficient, revealing that this transition corresponds to the onset of the spin reorientation. In the vicinity ofmore » TSR, a significantly larger in-plane magnetostrictive effect is observed, presenting the emergence of an intermediate phase that is highly susceptible to an applied magnetic field. X-ray linear dichroism shows that asymmetric Bi and Mn p orbitals do not play a role in the spin reorientation. Furthermore, this work suggests that the spin reorientation is caused by structural modification rather than changes in the local electronic configuration, providing a strategy for manipulating the magnetic anisotropy by external strain.« less

Giant magnetostriction effect near onset of spin reorientation in MnBi

DOE PAGES

Choi, Y.; Ryan, P. J.; McGuire, Michael A.; ...

2018-05-11

In materials undergoing spontaneous symmetry breaking transitions, the emergence of multiple competing order parameters is pervasive. Employing in-field x-ray diffraction, we investigate the temperature and magnetic field dependence of the crystallographic structure of MnBi, elucidating the microscopic interplay between lattices and spin. The hexagonal phase of MnBi undergoes a spin reorientation transition (TSR), whereby the easy axis direction changes from the c axis to the basal plane. Across TSR, an abrupt symmetry change is accompanied by a clear sign change in the magnetostrictive coefficient, revealing that this transition corresponds to the onset of the spin reorientation. In the vicinity ofmore » TSR, a significantly larger in-plane magnetostrictive effect is observed, presenting the emergence of an intermediate phase that is highly susceptible to an applied magnetic field. X-ray linear dichroism shows that asymmetric Bi and Mn p orbitals do not play a role in the spin reorientation. Furthermore, this work suggests that the spin reorientation is caused by structural modification rather than changes in the local electronic configuration, providing a strategy for manipulating the magnetic anisotropy by external strain.« less

Structural insight into the rearrangement of the switch I region in GTP-bound G12A K-Ras.

PubMed

Xu, Shenyuan; Long, Brian N; Boris, Gabriel H; Chen, Anqi; Ni, Shuisong; Kennedy, Michael A

2017-12-01

K-Ras, a molecular switch that regulates cell growth, apoptosis and metabolism, is activated when it undergoes a conformation change upon binding GTP and is deactivated following the hydrolysis of GTP to GDP. Hydrolysis of GTP in water is accelerated by coordination to K-Ras, where GTP adopts a high-energy conformation approaching the transition state. The G12A mutation reduces intrinsic K-Ras GTP hydrolysis by an unexplained mechanism. Here, crystal structures of G12A K-Ras in complex with GDP, GTP, GTPγS and GppNHp, and of Q61A K-Ras in complex with GDP, are reported. In the G12A K-Ras-GTP complex, the switch I region undergoes a significant reorganization such that the Tyr32 side chain points towards the GTP-binding pocket and forms a hydrogen bond to the GTP γ-phosphate, effectively stabilizing GTP in its precatalytic state, increasing the activation energy required to reach the transition state and contributing to the reduced intrinsic GTPase activity of G12A K-Ras mutants.

Structural insight into the rearrangement of the switch I region in GTP-bound G12A K-Ras

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Shenyuan; Long, Brian N.; Boris, Gabriel H.

K-Ras, a molecular switch that regulates cell growth, apoptosis and metabolism, is activated when it undergoes a conformation change upon binding GTP and is deactivated following the hydrolysis of GTP to GDP. Hydrolysis of GTP in water is accelerated by coordination to K-Ras, where GTP adopts a high-energy conformation approaching the transition state. The G12A mutation reduces intrinsic K-Ras GTP hydrolysis by an unexplained mechanism. Here, crystal structures of G12A K-Ras in complex with GDP, GTP, GTPγS and GppNHp, and of Q61A K-Ras in complex with GDP, are reported. In the G12A K-Ras–GTP complex, the switch I region undergoes amore » significant reorganization such that the Tyr32 side chain points towards the GTP-binding pocket and forms a hydrogen bond to the GTP γ-phosphate, effectively stabilizing GTP in its precatalytic state, increasing the activation energy required to reach the transition state and contributing to the reduced intrinsic GTPase activity of G12A K-Ras mutants.« less

Giant magnetostriction effect near onset of spin reorientation in MnBi

NASA Astrophysics Data System (ADS)

Choi, Y.; Ryan, P. J.; McGuire, M. A.; Sales, B. C.; Kim, J.-W.

2018-05-01

In materials undergoing spontaneous symmetry breaking transitions, the emergence of multiple competing order parameters is pervasive. Employing in-field x-ray diffraction, we investigate the temperature and magnetic field dependence of the crystallographic structure of MnBi, elucidating the microscopic interplay between lattices and spin. The hexagonal phase of MnBi undergoes a spin reorientation transition (TSR), whereby the easy axis direction changes from the c axis to the basal plane. Across TSR, an abrupt symmetry change is accompanied by a clear sign change in the magnetostrictive coefficient, revealing that this transition corresponds to the onset of the spin reorientation. In the vicinity of TSR, a significantly larger in-plane magnetostrictive effect is observed, presenting the emergence of an intermediate phase that is highly susceptible to an applied magnetic field. X-ray linear dichroism shows that asymmetric Bi and Mn p orbitals do not play a role in the spin reorientation. This work suggests that the spin reorientation is caused by structural modification rather than changes in the local electronic configuration, providing a strategy for manipulating the magnetic anisotropy by external strain.

Hybrid Wing-Body (HWB) Pressurized Fuselage Modeling, Analysis, and Design for Weight Reduction

NASA Technical Reports Server (NTRS)

Mukhopadhyay, Vivek

2012-01-01

This paper describes the interim progress for an in-house study that is directed toward innovative structural analysis and design of next-generation advanced aircraft concepts, such as the Hybrid Wing-Body (HWB) and the Advanced Mobility Concept-X flight vehicles, for structural weight reduction and associated performance enhancement. Unlike the conventional, skin-stringer-frame construction for a cylindrical fuselage, the box-type pressurized fuselage panels in the HWB undergo significant deformation of the outer aerodynamic surfaces, which must be minimized without significant structural weight penalty. Simple beam and orthotropic plate theory is first considered for sizing, analytical verification, and possible equivalent-plate analysis with appropriate simplification. By designing advanced composite stiffened-shell configurations, significant weight reduction may be possible compared with the sandwich and ribbed-shell structural concepts that have been studied previously. The study involves independent analysis of the advanced composite structural concepts that are presently being developed by The Boeing Company for pressurized HWB flight vehicles. High-fidelity parametric finite-element models of test coupons, panels, and multibay fuselage sections, were developed for conducting design studies and identifying critical areas of potential failure. Interim results are discussed to assess the overall weight/strength advantages.

Structural and chemical evolution of the CdS:O window layer during individual CdTe solar cell processing steps

DOE PAGES

Abbas, A.; Meysing, D. M.; Reese, M. O.; ...

2017-12-01

Oxygenated cadmium sulfide (CdS:O) is often used as the n-type window layer in high-performance CdTe heterojunction solar cells. The as-deposited layer prepared by reactive sputtering is XRD amorphous, with a bulk composition of CdS0.8O1.2. Recently it was shown that this layer undergoes significant transformation during device fabrication, but the roles of the individual high temperature processing steps was unclear. In this work high resolution transmission electron microscopy coupled to elemental analysis was used to understand the evolution of the heterojunction region through the individual high temperature fabrication steps of CdTe deposition, CdCl2 activation, and back contact activation. It is foundmore » that during CdTe deposition by close spaced sublimation at 600 degrees C the CdS:O film undergoes recrystallization, accompanied by a significant (~30%) reduction in thickness. It is observed that oxygen segregates during this step, forming a bi-layer morphology consisting of nanocrystalline CdS adjacent to the tin oxide contact and an oxygen-rich layer adjacent to the CdTe absorber. This bilayer structure is then lost during the 400 degrees C CdCl2 treatment where the film transforms into a heterogeneous structure with cadmium sulfate clusters distributed randomly throughout the window layer. The thickness of window layer remains essentially unchanged after CdCl2 treatment, but a ~25 nm graded interfacial layer between CdTe and the window region is formed. Finally, the rapid thermal processing step used to activate the back contact was found to have a negligible impact on the structure or composition of the heterojunction region.« less

Structural and chemical evolution of the CdS:O window layer during individual CdTe solar cell processing steps

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abbas, A.; Meysing, D. M.; Reese, M. O.

Oxygenated cadmium sulfide (CdS:O) is often used as the n-type window layer in high-performance CdTe heterojunction solar cells. The as-deposited layer prepared by reactive sputtering is XRD amorphous, with a bulk composition of CdS0.8O1.2. Recently it was shown that this layer undergoes significant transformation during device fabrication, but the roles of the individual high temperature processing steps was unclear. In this work high resolution transmission electron microscopy coupled to elemental analysis was used to understand the evolution of the heterojunction region through the individual high temperature fabrication steps of CdTe deposition, CdCl2 activation, and back contact activation. It is foundmore » that during CdTe deposition by close spaced sublimation at 600 degrees C the CdS:O film undergoes recrystallization, accompanied by a significant (~30%) reduction in thickness. It is observed that oxygen segregates during this step, forming a bi-layer morphology consisting of nanocrystalline CdS adjacent to the tin oxide contact and an oxygen-rich layer adjacent to the CdTe absorber. This bilayer structure is then lost during the 400 degrees C CdCl2 treatment where the film transforms into a heterogeneous structure with cadmium sulfate clusters distributed randomly throughout the window layer. The thickness of window layer remains essentially unchanged after CdCl2 treatment, but a ~25 nm graded interfacial layer between CdTe and the window region is formed. Finally, the rapid thermal processing step used to activate the back contact was found to have a negligible impact on the structure or composition of the heterojunction region.« less

Reversible “triple-Q” elastic field structures in a chiral magnet

PubMed Central

Hu, Yangfan; Wang, Biao

2016-01-01

The analytical solution of the periodic elastic fields in chiral magnets caused by presence of periodically distributed eigenstrains is obtained. For the skyrmion phase, both the periodic displacement field and the stress field are composed of three “triple-Q” structures with different wave numbers. The periodic displacement field, obtained by combining the three “triple-Q” displacement structures, is found to have the same lattice vectors with the magnetic skyrmion lattice. We find that for increasing external magnetic field, one type of “triple-Q” displacement structure and stress structure undergo a “configurational reversal”, where the initial and the final field configuration share similar pattern but with opposite direction of all the field vectors. The solution obtained is of fundamental significance for understanding the emergent mechanical properties of skyrmions in chiral magnets. PMID:27457629

Effect of Structured Touch and Guided Imagery for Pain and Anxiety in Elective Joint Replacement Patients--A Randomized Controlled Trial: M-TIJRP.

PubMed

Forward, John Brent; Greuter, Nancy Elizabeth; Crisall, Santa J; Lester, Houston F

2015-01-01

Postoperative management of pain after total joint arthroplasty remains a challenge despite advancements in analgesics. Evidence shows that complementary modalities with mind-body and tactile-based approaches are valid and effective adjuncts to reduce pain and anxiety postoperatively. To investigate the effectiveness of the "M" Technique (M), a registered method of structured touch using a set sequence and number of strokes, and a consistent level of pressure on hands and feet, compared with guided imagery and usual care, for the reduction of pain and anxiety in patients undergoing elective total knee or hip replacement surgery. Randomized controlled trial: M-TIJRP (MiTechnique and guided Imagery in Joint Replacement Patients [Mighty Junior P]). At a community hospital, 225 male and female patients, aged 38 to 90 years, undergoing elective total hip or knee replacement were randomly assigned to 1 of 3 groups (75 patients in each): M, guided imagery, or usual care. They were blinded to their assignment until the intervention. Reduction of pain and anxiety postoperatively. Secondary outcomes measured use of pain medication and patient satisfaction. This study yielded positive findings for the management of pain and anxiety in patients undergoing elective joint replacement using M and guided imagery for 18 to 20 minutes compared with usual care. M showed the largest predicted decreases in both pain and anxiety between groups. There was no significant difference in narcotic pain medication use between groups. Patient satisfaction survey ratings were highest for M, followed by guided imagery. The benefit of M may be because of the specifically structured sequence of touch by competent caring, trained providers.

Effect of Structured Touch and Guided Imagery for Pain and Anxiety in Elective Joint Replacement Patients—A Randomized Controlled Trial: M-TIJRP

PubMed Central

Forward, John Brent; Greuter, Nancy Elizabeth; Crisall, Santa J; Lester, Houston F

2015-01-01

Context: Postoperative management of pain after total joint arthroplasty remains a challenge despite advancements in analgesics. Evidence shows that complementary modalities with mind-body and tactile-based approaches are valid and effective adjuncts to reduce pain and anxiety postoperatively. Objective: To investigate the effectiveness of the “M” Technique (M), a registered method of structured touch using a set sequence and number of strokes, and a consistent level of pressure on hands and feet, compared with guided imagery and usual care, for the reduction of pain and anxiety in patients undergoing elective total knee or hip replacement surgery. Methods: Randomized controlled trial: M-TIJRP (MiTechnique and guided Imagery in Joint Replacement Patients [Mighty Junior P]). At a community hospital, 225 male and female patients, aged 38 to 90 years, undergoing elective total hip or knee replacement were randomly assigned to 1 of 3 groups (75 patients in each): M, guided imagery, or usual care. They were blinded to their assignment until the intervention. Main Outcome Measures: Reduction of pain and anxiety postoperatively. Secondary outcomes measured use of pain medication and patient satisfaction. Results: This study yielded positive findings for the management of pain and anxiety in patients undergoing elective joint replacement using M and guided imagery for 18 to 20 minutes compared with usual care. M showed the largest predicted decreases in both pain and anxiety between groups. There was no significant difference in narcotic pain medication use between groups. Patient satisfaction survey ratings were highest for M, followed by guided imagery. Conclusion: The benefit of M may be because of the specifically structured sequence of touch by competent caring, trained providers. PMID:26222093

Haemodynamic results of replacement of mitral and aortic valves with autologous fascia lata prostheses

PubMed Central

Talavlikar, P. H.; Walbaum, P. R.; Kitchin, A. H.

1973-01-01

Twelve patients undergoing aortic and 28 undergoing mitral valve replacement with autologous fascia lata valves were studied before and six months after surgery. One aortic and 10 mitral valves were found to be significantly incompetent. Of the incompetent mitral valves, two appeared to have perivalvular leaks. Six of the remainder were associated with abnormal ventricular filling patterns. Valve failure was much less common when the design was modified to provide a loose cusp structure; out of 12 such valves none was incompetent. Transvalvular gradients persist with fascial valves though they are lower than with most mechanical prostheses. Ventricular function was greatly improved in successful aortic replacement but remained impaired in the case of mitral replacement. Valve failure appeared to be associated with, or accelerated by, haemodynamic stress rather than due to inevitable degenerative pathological processes. PMID:4731108

Quantifying the bending of bilayer temperature-sensitive hydrogels

NASA Astrophysics Data System (ADS)

Dong, Chenling; Chen, Bin

2017-04-01

Stimuli-responsive hydrogels can serve as manipulators, including grippers, sensors, etc., where structures can undergo significant bending. Here, a finite-deformation theory is developed to quantify the evolution of the curvature of bilayer temperature-sensitive hydrogels when subjected to a temperature change. Analysis of the theory indicates that there is an optimal thickness ratio to acquire the largest curvature in the bilayer and also suggests that the sign or the magnitude of the curvature can be significantly affected by pre-stretches or small pores in the bilayer. This study may provide important guidelines in fabricating temperature-responsive bilayers with desirable mechanical performance.

Granisetron plus dexamethasone for prevention of postoperative nausea and vomiting in patients undergoing laparoscopic surgery: A meta-analysis

PubMed Central

Zhu, Min; Zhou, Chengmao; Huang, Bing; Ruan, Lin; Liang, Rui

2017-01-01

Objective This study was designed to compare the effectiveness of granisetron plus dexamethasone for preventing postoperative nausea and vomiting (PONV) in patients undergoing laparoscopic surgery. Methods We searched the literature in the Cochrane Library, PubMed, EMBASE, and CNKI. Results In total, 11 randomized controlled trials were enrolled in this analysis. The meta-analysis showed that granisetron in combination with dexamethasone was significantly more effective than granisetron alone in preventing PONV in patients undergoing laparoscopy surgery. No significant differences in adverse reactions (dizziness and headache) were found in association with dexamethasone. Conclusion Granisetron in combination with dexamethasone was significantly more effective than granisetron alone in preventing PONV in patients undergoing laparoscopic surgery, with no difference in adverse reactions between the two groups. Granisetron alone or granisetron plus dexamethasone can be used to prevent PONV in patients undergoing laparoscopic surgery. PMID:28436248

Granisetron plus dexamethasone for prevention of postoperative nausea and vomiting in patients undergoing laparoscopic surgery: A meta-analysis.

PubMed

Zhu, Min; Zhou, Chengmao; Huang, Bing; Ruan, Lin; Liang, Rui

2017-06-01

Objective This study was designed to compare the effectiveness of granisetron plus dexamethasone for preventing postoperative nausea and vomiting (PONV) in patients undergoing laparoscopic surgery. Methods We searched the literature in the Cochrane Library, PubMed, EMBASE, and CNKI. Results In total, 11 randomized controlled trials were enrolled in this analysis. The meta-analysis showed that granisetron in combination with dexamethasone was significantly more effective than granisetron alone in preventing PONV in patients undergoing laparoscopy surgery. No significant differences in adverse reactions (dizziness and headache) were found in association with dexamethasone. Conclusion Granisetron in combination with dexamethasone was significantly more effective than granisetron alone in preventing PONV in patients undergoing laparoscopic surgery, with no difference in adverse reactions between the two groups. Granisetron alone or granisetron plus dexamethasone can be used to prevent PONV in patients undergoing laparoscopic surgery.

[Change in Perioperative Hemostatic Function in Patients Undergoing Hepatic Resection for Primary and Metastatic Liver Cancer].

PubMed

Komasawa, Nobuyasu; Ueki, Ryusuke; Atagi, Kazuaki; Nishi, Shinichi

2015-08-01

Patients undergoing primary hepatic resection often develop hemostatic dysfunction associated with cirrhosis. We retrospectively surveyed pre- and postoperative prothrombin time (PT) and the PT expressed as international normalized ratio (PT-INR) in 39 patients undergoing primary liver resection. We also compared PT changes between primary and metastatic cancer cases (8 cases). Postoperative PT-INR was 1.40 ± 0.38, which was significantly prolonged compared to preoperative PT-INR of 1.08 ± 0.07. Preoperative PT was over 70% in all 39 patients undergoing primary liver resection, whereas postoperative PT was less than 60% in 13 of 39 patients. No significant difference was found in preoperative PT-INR between primary and metastatic cancer cases, but postoperative PT-INR was significantly prolonged in primary cancer cases. Patients undergoing primary liver resection are susceptible to hemostatic dysfunction, even with preoperative PT levels within normal limits.

Structure of the Newcastle disease virus F protein in the post-fusion conformation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Swanson, Kurt; Wen, Xiaolin; Leser, George P.

2010-11-17

The paramyxovirus F protein is a class I viral membrane fusion protein which undergoes a significant refolding transition during virus entry. Previous studies of the Newcastle disease virus, human parainfluenza virus 3 and parainfluenza virus 5 F proteins revealed differences in the pre- and post-fusion structures. The NDV Queensland (Q) F structure lacked structural elements observed in the other two structures, which are key to the refolding and fusogenic activity of F. Here we present the NDV Australia-Victoria (AV) F protein post-fusion structure and provide EM evidence for its folding to a pre-fusion form. The NDV AV F structure containsmore » heptad repeat elements missing in the previous NDV Q F structure, forming a post-fusion six-helix bundle (6HB) similar to the post-fusion hPIV3 F structure. Electrostatic and temperature factor analysis of the F structures points to regions of these proteins that may be functionally important in their membrane fusion activity.« less

The Evaluation of Relationship between Sexual Self-concept and Sexual Dysfunction in Individuals Undergoing Methadone Maintenance Treatment

PubMed Central

Rajabizadeh, Ghodratolah; Yazdanpanah, Fatemeh; Ramezani, Mohammad Arash

2017-01-01

Background The present study was conducted with the aim of designing a causal model for the evaluation of sexual dysfunctions based on the variables of methadone dosage and sexual self-concept among individuals undergoing methadone maintenance treatment (MMT). Methods The study population of the present study consisted of married men of 20 to 45 years of age with sexual ýrelations and undergoing MMT for a minimum of 8 weeks referring to all MMT clinics of Kerman, Iran, in ýý2015-2016. ýThe subjects were selected through multi-stage cluster sampling (n = 250). Data were collected using the General Health Questionnaire (GHQ-28), Multi-Dimensional Sexual Self-concept Questionnaire (MSSQ), and Internal Index for Erectile Function (IIEF). Data were analyzed using path analysis method and Pearson correlation coefficient. The suggested model was evaluated using structural equation model (SEM), and indirect relationships were assessed using Bootstrap method. Findings The suggested model showed acceptable fitness with the data, and all routes, except methadone use route, to sexual function were significant. The result of the multiple ýindirect route showed that sexual function had a significant relationship with methadone use through ýsexual self-concept. In total, 60% of variance in sexual dysfunction was explained using the variables of the suggested model. Conclusion Further studies are suggested to be conducted regarding psychological factors effective on the sexual dysfunctions among individuals undergoing MMT, such as sexual self-concept. Moreover, more detailed evaluation of each subscale of positive and negative sexual self-concept is recommended to assess the psychological causes of sexual dysfunctions in these individuals and design psychological, behavioral, and cognitive-behavioral treatment interventions for them. PMID:29299211

The Evaluation of Relationship between Sexual Self-concept and Sexual Dysfunction in Individuals Undergoing Methadone Maintenance Treatment.

PubMed

Rajabizadeh, Ghodratolah; Yazdanpanah, Fatemeh; Ramezani, Mohammad Arash

2017-04-01

The present study was conducted with the aim of designing a causal model for the evaluation of sexual dysfunctions based on the variables of methadone dosage and sexual self-concept among individuals undergoing methadone maintenance treatment (MMT). The study population of the present study consisted of married men of 20 to 45 years of age with sexual ýrelations and undergoing MMT for a minimum of 8 weeks referring to all MMT clinics of Kerman, Iran, in ýý2015-2016. ýThe subjects were selected through multi-stage cluster sampling (n = 250). Data were collected using the General Health Questionnaire (GHQ-28), Multi-Dimensional Sexual Self-concept Questionnaire (MSSQ), and Internal Index for Erectile Function (IIEF). Data were analyzed using path analysis method and Pearson correlation coefficient. The suggested model was evaluated using structural equation model (SEM), and indirect relationships were assessed using Bootstrap method. The suggested model showed acceptable fitness with the data, and all routes, except methadone use route, to sexual function were significant. The result of the multiple ýindirect route showed that sexual function had a significant relationship with methadone use through ýsexual self-concept. In total, 60% of variance in sexual dysfunction was explained using the variables of the suggested model. Further studies are suggested to be conducted regarding psychological factors effective on the sexual dysfunctions among individuals undergoing MMT, such as sexual self-concept. Moreover, more detailed evaluation of each subscale of positive and negative sexual self-concept is recommended to assess the psychological causes of sexual dysfunctions in these individuals and design psychological, behavioral, and cognitive-behavioral treatment interventions for them.

Tough, Microcracking-Resistant, High-Temperature Polymer

NASA Technical Reports Server (NTRS)

Pater, Ruth H.; Razon, Pert; Smith, Ricky; Working, Dennis; Chang, Alice; Gerber, Margaret

1990-01-01

Simultaneous synthesis from thermosetting and thermoplastic components yields polyimide with outstanding properties. Involves process in which one polymer cross-linked in immediate presence of other, undergoing simultaneous linear chain extension. New material, LaRC-RP40 synthesized from high-temperature thermosetting imide prepolymer and from thermoplastic monomer. Three significantly improved properties: toughness, resistance to microcracking, and glass-transition temperature. Shows promise as high-temperature matrix resin for variety of components of aircraft engines and for use in other aerospace structures.

Phenotypic modulation of corpus cavernosum smooth muscle cells in a rat model of cavernous neurectomy.

PubMed

Yang, Fan; Zhao, Jian F; Shou, Qi Y; Huang, Xiao J; Chen, Gang; Yang, Ke B; Zhang, Shi G; Lv, Bo D; Fu, Hui Y

2014-01-01

Patients undergoing radical prostatectomy (RP) are at high risk for erectile dysfunction (ED) due to potential cavernous nerve (CN) damage during surgery. Penile hypoxia after RP is thought to significantly contribute to ED pathogenesis. We previously showed that corpora cavernosum smooth muscle cells (CCSMCs) undergo phenotypic modulation under hypoxic conditions in vitro. Here, we studied such changes in an in vivo post-RP ED model by investigating CCSMCs in bilateral cavernous neurectomy (BCN) rats. Sprague-Dawley rats underwent sham (n = 12) or BCN (n = 12) surgery. After 12 weeks, they were injected with apomorphine to determine erectile function. The penile tissues were harvested and assessed for fibrosis using Masson trichrome staining and for molecular markers of phenotypic modulation using immunohistochemistry and western blotting. CCSMC morphological structure was evaluated by hematoxylin-eosin (H&E) staining and transmission electron microscopy (TEM). Erectile function was significantly lower in BCN rats than in sham rats. BCN increased hypoxia-inducible factor-1α and collagen protein expression in corpora cavernous tissue. H&E staining and TEM showed that CCSMCs in BCN rats underwent hypertrophy and showed rough endoplasmic reticulum formation. The expression of CCSMC phenotypic markers, such as smooth muscle α-actin, smooth muscle myosin heavy chain, and desmin, was markedly lower, whereas vimentin protein expression was significantly higher in BCN rats than in control rats. CCSMCs undergo phenotype modulation in rats with cavernous neurectomy. The results have unveiled physiological transformations that occur at the cellular and molecular levels and have helped characterize CN injury-induced ED.

Active vibration control of structures undergoing bending vibrations

NASA Technical Reports Server (NTRS)

Pla, Frederic G. (Inventor); Rajiyah, Harindra (Inventor)

1995-01-01

An active vibration control subassembly for a structure (such as a jet engine duct or a washing machine panel) undergoing bending vibrations caused by a source (such as the clothes agitator of the washing machine) independent of the subassembly. A piezoceramic actuator plate is vibratable by an applied electric AC signal. The plate is connected to the structure such that vibrations in the plate induced by the AC signal cause canceling bending vibrations in the structure and such that the plate is compressively pre-stressed along the structure when the structure is free of any bending vibrations. The compressive prestressing increases the amplitude of the canceling bending vibrations before the critical tensile stress level of the plate is reached. Preferably, a positive electric DC bias is also applied to the plate in its poling direction.

[The Relationship Between Coping Behaviors and Symptom Distress in Elderly Patients With Cancer Undergoing Initial Chemotherapy].

PubMed

Wu, Shih-Ping; Hsu, Ya-Chuan

2016-12-01

Elderly cancer patients undergoing initial chemotherapy often suffer discomfort from medication-related symptom distress. This discomfort may affect treatment responses and outcomes negatively. This correlational, cross-sectional design study used a purposive sample of 100 patients who were both over 60 years of age and currently undergoing initial chemotherapy. The participants completed a structured questionnaire that was administered at a medical center in southern Taiwan. The questionnaire included a demographics datasheet, Coping Behavior Scale, and Symptom Distress Scale. Data was analyzed using descriptive statistics, Pearson's correlations, Mann-Whitney U, and Kruskal Wallis tests, which were run on SPSS 19.0 software. This correlational, cross-sectional design study used a purposive sample of 100 patients who were both over 60 years of age and currently undergoing initial chemotherapy. The participants completed a structured questionnaire that was administered at a medical center in southern Taiwan. The questionnaire included a demographics datasheet, Coping Behavior Scale, and Symptom Distress Scale. Data was analyzed using descriptive statistics, Pearson's correlations, Mann-Whitney U, and Kruskal Wallis tests, which were run on SPSS 19.0 software. Three-quarters (78%) of participants reported that they suffered from more than four distress symptoms. The top distress symptoms in terms of severity included: fatigue, poor appetite, insomnia, dry mouth, and altered bowel habits. The top distress symptoms in terms of frequency included: fatigue, dry mouth, poor appetite, insomnia, and altered bowel habits. "Problem-focused" coping was the most frequent type of coping behavior (mean = 3.19, SD = 0.24) that was used by participants. Furthermore, more frequent use of "emotions-focused" coping behaviors was associated with a greater risk of experiencing serious distress symptoms (r =.44, p < .001). Number of chronic diseases, cancer stage, and type of cancer treatment had no significant influence of symptom distress. Findings confirmed the relationship between coping behavior and symptom distress in elderly Taiwanese cancer patients undergoing initial chemotherapy. The results suggest that healthcare providers may use interventions that target patient coping behavior in order to alleviate the chemotherapy-induced symptoms of distress in elderly cancer patients.

Acute hypoxia stress induced abundant differential expression genes and alternative splicing events in heart of tilapia.

PubMed

Xia, Jun Hong; Li, Hong Lian; Li, Bi Jun; Gu, Xiao Hui; Lin, Hao Ran

2018-01-10

Hypoxia is one of the critical environmental stressors for fish in aquatic environments. Although accumulating evidences indicate that gene expression is regulated by hypoxia stress in fish, how genes undergoing differential gene expression and/or alternative splicing (AS) in response to hypoxia stress in heart are not well understood. Using RNA-seq, we surveyed and detected 289 differential expressed genes (DEG) and 103 genes that undergo differential usage of exons and splice junctions events (DUES) in heart of a hypoxia tolerant fish, Nile tilapia, Oreochromis niloticus following 12h hypoxic treatment. The spatio-temporal expression analysis validated the significant association of differential exon usages in two randomly selected DUES genes (fam162a and ndrg2) in 5 tissues (heart, liver, brain, gill and spleen) sampled at three time points (6h, 12h, and 24h) under acute hypoxia treatment. Functional analysis significantly associated the differential expressed genes with the categories related to energy conservation, protein synthesis and immune response. Different enrichment categories were found between the DEG and DUES dataset. The Isomerase activity, Oxidoreductase activity, Glycolysis and Oxidative stress process were significantly enriched for the DEG gene dataset, but the Structural constituent of ribosome and Structural molecule activity, Ribosomal protein and RNA binding protein were significantly enriched only for the DUES genes. Our comparative transcriptomic analysis reveals abundant stress responsive genes and their differential regulation function in the heart tissues of Nile tilapia under acute hypoxia stress. Our findings will facilitate future investigation on transcriptome complexity and AS regulation during hypoxia stress in fish. Copyright © 2017 Elsevier B.V. All rights reserved.

Structural and magnetic transitions in spinel FeM n 2 O 4 single crystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nepal, Roshan; Zhang, Qiang; Dai, Samuel

Materials that form the spinel structure are known to exhibit geometric frustration, which can lead to magnetic frustration as well. Through magnetization and neutron diffraction measurements, we find that FeMn 2O 4 undergoes one structural and two magnetic transitions. The structural transition occurs at T s ~595K from cubic at high temperatures to tetragonal at low temperatures. Here, two magnetic transitions are ferrimagnetic at T FI–1 ~373K and T FI–2 ~50K, respectively. Further investigation of the specific heat, thermal conductivity, and Seebeck coefficient confirms both magnetic transitions. Of particular interest is that there is a significant magnetic contribution to themore » low-temperature specific heat and thermal conductivity, providing a unique system to study heat transport by magnetic excitations.« less

Structural and magnetic transitions in spinel FeM n 2 O 4 single crystals

DOE PAGES

Nepal, Roshan; Zhang, Qiang; Dai, Samuel; ...

2018-01-11

Materials that form the spinel structure are known to exhibit geometric frustration, which can lead to magnetic frustration as well. Through magnetization and neutron diffraction measurements, we find that FeMn 2O 4 undergoes one structural and two magnetic transitions. The structural transition occurs at T s ~595K from cubic at high temperatures to tetragonal at low temperatures. Here, two magnetic transitions are ferrimagnetic at T FI–1 ~373K and T FI–2 ~50K, respectively. Further investigation of the specific heat, thermal conductivity, and Seebeck coefficient confirms both magnetic transitions. Of particular interest is that there is a significant magnetic contribution to themore » low-temperature specific heat and thermal conductivity, providing a unique system to study heat transport by magnetic excitations.« less

Giant star seismology

NASA Astrophysics Data System (ADS)

Hekker, S.; Christensen-Dalsgaard, J.

2017-06-01

The internal properties of stars in the red-giant phase undergo significant changes on relatively short timescales. Long near-uninterrupted high-precision photometric timeseries observations from dedicated space missions such as CoRoT and Kepler have provided seismic inferences of the global and internal properties of a large number of evolved stars, including red giants. These inferences are confronted with predictions from theoretical models to improve our understanding of stellar structure and evolution. Our knowledge and understanding of red giants have indeed increased tremendously using these seismic inferences, and we anticipate that more information is still hidden in the data. Unraveling this will further improve our understanding of stellar evolution. This will also have significant impact on our knowledge of the Milky Way Galaxy as well as on exo-planet host stars. The latter is important for our understanding of the formation and structure of planetary systems.

iATTRACT: simultaneous global and local interface optimization for protein-protein docking refinement.

PubMed

Schindler, Christina E M; de Vries, Sjoerd J; Zacharias, Martin

2015-02-01

Protein-protein interactions are abundant in the cell but to date structural data for a large number of complexes is lacking. Computational docking methods can complement experiments by providing structural models of complexes based on structures of the individual partners. A major caveat for docking success is accounting for protein flexibility. Especially, interface residues undergo significant conformational changes upon binding. This limits the performance of docking methods that keep partner structures rigid or allow limited flexibility. A new docking refinement approach, iATTRACT, has been developed which combines simultaneous full interface flexibility and rigid body optimizations during docking energy minimization. It employs an atomistic molecular mechanics force field for intermolecular interface interactions and a structure-based force field for intramolecular contributions. The approach was systematically evaluated on a large protein-protein docking benchmark, starting from an enriched decoy set of rigidly docked protein-protein complexes deviating by up to 15 Å from the native structure at the interface. Large improvements in sampling and slight but significant improvements in scoring/discrimination of near native docking solutions were observed. Complexes with initial deviations at the interface of up to 5.5 Å were refined to significantly better agreement with the native structure. Improvements in the fraction of native contacts were especially favorable, yielding increases of up to 70%. © 2014 Wiley Periodicals, Inc.

On the analytical modeling of the nonlinear vibrations of pretensioned space structures

NASA Technical Reports Server (NTRS)

Housner, J. M.; Belvin, W. K.

1983-01-01

Pretensioned structures are receiving considerable attention as candidate large space structures. A typical example is a hoop-column antenna. The large number of preloaded members requires efficient analytical methods for concept validation and design. Validation through analyses is especially important since ground testing may be limited due to gravity effects and structural size. The present investigation has the objective to present an examination of the analytical modeling of pretensioned members undergoing nonlinear vibrations. Two approximate nonlinear analysis are developed to model general structural arrangements which include beam-columns and pretensioned cables attached to a common nucleus, such as may occur at a joint of a pretensioned structure. Attention is given to structures undergoing nonlinear steady-state oscillations due to sinusoidal excitation forces. Three analyses, linear, quasi-linear, and nonlinear are conducted and applied to study the response of a relatively simple cable stiffened structure.

Gene Expression Profiling Identifies FKBP39 as an Inhibitor of Autophagy in Larval Drosophila Fat Body

PubMed Central

Juhász, Gábor; Puskás, László G.; Komonyi, Orbán; Érdi, Balázs; Maróy, Péter; Neufeld, Thomas P.; Sass, Miklós

2007-01-01

In Drosophila, the fat body undergoes a massive burst of autophagy at the end of larval development in preparation for the pupal transition. To identify genes involved in this process, we carried out a microarray analysis. We found that mRNA levels of the homologs of Atg8, the coat protein of early autophagic structures, and lysosomal hydrolases were upregulated, consistent with previous results. Genes encoding mitochondrial proteins and many chaperones were downregulated, including the inhibitor of eIF2alpha kinases and the peptidyl-prolyl cis-trans isomerase (PPiase) FKBP39. Genetic manipulation of FKBP39 expression had a significant effect on autophagy, potentially through modulation of the transcription factor Foxo. Accordingly, we found that Foxo mutants can not properly undergo autophagy in response to starvation, and that overexpression of Foxo induces autophagy. PMID:17363962

Effects of type of exercise on depression in recovering substance abusers.

PubMed

Palmer, J A; Palmer, L K; Michiels, K; Thigpen, B

1995-04-01

This experiment investigated the effects of three types of structured exercise (aerobics, bodybuilding, and circuit training) on depressive symptoms of 45 clients undergoing a 4-wk., inpatient rehabilitation program for substance abuse. Pre- and posttest measures included the Center of Epidemiological Studies--Depression, resting pulse rate, blood pressure, maximum strength on incline bench press, and estimates of aerobic fitness and body fat. The bodybuilding program produced a significant decrease in depressive symptoms. Physiological and psychological explanations are discussed.

Medical education: Changes and perspectives

PubMed Central

Zhang, Qin; Lee, Liming; Gruppen, Larry D.; Ba, Denian

2013-01-01

As medical education undergoes significant internationalization, it is important for the medical education community to understand how different countries structure and provide medical education. This article highlights the current landscape of medical education in China, particularly the changes that have taken place in recent years. It also examines policies and offers suggestions about future strategies for medical education in China. Although many of these changes reflect international trends, Chinese medical education has seen unique transformations that reflect its particular culture and history. PMID:23631405

Environmental effects on composite airframes: A study conducted for the ARM UAV Program (Atmospheric Radiation Measurement Unmanned Aerospace Vehicle)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Noguchi, R.A.

1994-06-01

Composite materials are affected by environments differently than conventional airframe structural materials are. This study identifies the environmental conditions which the composite-airframe ARM UAV may encounter, and discusses the potential degradation processes composite materials may undergo when subjected to those environments. This information is intended to be useful in a follow-on program to develop equipment and procedures to prevent, detect, or otherwise mitigate significant degradation with the ultimate goal of preventing catastrophic aircraft failure.

Unusual structural transition of antimicrobial VP1 peptide.

PubMed

Shanmugam, Ganesh; Phambu, Nsoki; Polavarapu, Prasad L

2011-05-01

VP1 peptide, an active domain of m-calpain enzyme with antimicrobial activity is found to undergo an unusual conformational transition in trifluoroethanol (TFE) solvent. The nature of, and time dependent variations in, circular dichroism associated with the amide I vibrations, suggest that VP1 undergoes self-aggregation forming anti-parallel β-sheet structure in TFE. Transmission electron micrograph (TEM) images revealed that β-sheet aggregates formed by VP1 possess fibril-like assemblies. Copyright © 2011 Elsevier B.V. All rights reserved.

Cardiac size of high-volume resistance trained female athletes: shaping the body but not the heart.

PubMed

Venckunas, T; Simonavicius, J; Marcinkeviciene, J E

2016-03-01

Introduction Exercise training, besides many health benefits, may result in cardiac remodelling which is dependent on the type and amount of exercise performed. It is not clear, however, whether significant adaptation in cardiac structure is possible in females undergoing resistance type of exercise training. Rigorous high volume training of most muscle groups emphasising resistance exercises are being undertaken by athletes of some aesthetic sports such as female fitness (light bodybuilding). The impact of this type of training on cardiac adaptation has not been investigated until now. The aim of the current study was to disclose the effect of high volume resistance training on cardiac structure and function. Methods 11 top-level female fitness athletes and 20 sedentary age-matched controls were recruited to undergo two-dimensional echocardiography. Results Cardiac structure did not differ between elite female fitness athletes and controls (p > 0.05), and fitness athletes had a tendency for a smaller (p = 0.07) left ventricular (LV) mass indexed to lean body mass. Doppler diastolic function index (E/A ratio) and LV ejection fraction were similar between the groups (p > 0.05). Conclusions Elite female fitness athletes have normal cardiac size and function that do not differ from matched sedentary controls. Consequently, as high volume resistance training has no easily observable effect on adaptation of cardiac structure, when cardiac hypertrophy is present in young resistance-trained lean female, other reasons such as inherited cardiac disease are to be considered carefully.

Comparison between cerebrospinal fluid and serum lactate concentrations in neurologic dogs with and without structural intracranial disease.

PubMed

Benedicenti, Leontine; Gianotti, Giacomo; Galban, Evelyn M

2018-04-01

The objectives of this study were to investigate the relationship between cerebrospinal fluid lactate and serum concentrations in dogs with clinical signs of central nervous system disease and to establish if cerebrospinal fluid lactate (CSF) concentrations are higher in dogs with structural intracranial disease (Group Pos-MRI) compared to dogs that have clinical signs of intracranial disease but no structural brain disease (Group Neg-MRI) based on magnetic resonance imaging (MRI) findings. Using a prospective study canine blood and cerebrospinal fluid were collected in 24 dogs with neurological signs after undergoing brain MRI. Dogs were divided in 2 groups. No significant difference between serum lactate (1.57 ± 0.9 mmol/L) and CSF lactate concentration (1.34 ± 0.3 mmol/L) was detected. There was a direct correlation between CSF and serum lactate concentration ( R = 0.731; P = 0.01). No significant difference was found in CSF lactate concentration between the 2 groups of dogs ( P = 0.13).

Vortex shedding within laminar separation bubbles forming over an airfoil

NASA Astrophysics Data System (ADS)

Kirk, Thomas M.; Yarusevych, Serhiy

2017-05-01

Vortex shedding within laminar separation bubbles forming over the suction side of a NACA 0018 airfoil is studied through a combination of high-speed flow visualization and boundary layer measurements. Wind tunnel experiments are performed at a chord-based Reynolds number of 100,000 and four angles of attack. The high-speed flow visualization is complemented by quantitative velocity and surface pressure measurements. The structures are shown to originate from the natural amplification of small-amplitude disturbances, and the shear layer roll-up is found to occur coherently across the span. However, significant cycle-to-cycle variations are observed in vortex characteristics, including shedding period and roll-up location. The formation of the roll-up vortices precedes the later stages of transition, during which these structures undergo significant deformations and breakdown to smaller scales. During this stage of flow development, vortex merging is also observed. The results provide new insight into the development of coherent structures in separation bubbles and their relation to the overall bubble dynamics and mean bubble topology.

Acid-catalyzed conversion of mono- and poly-sugars into platform chemicals: effects of molecular structure of sugar substrate.

PubMed

Hu, Xun; Wu, Liping; Wang, Yi; Song, Yao; Mourant, Daniel; Gunawan, Richard; Gholizadeh, Mortaza; Li, Chun-Zhu

2013-04-01

Hydrolysis/pyrolysis of lignocellulosic biomass always produces a mixture of sugars with distinct structures as intermediates or products. This study tried to elucidate the effects of molecular structure of sugars on their acid-catalyzed conversions in ethanol/water. Location of carbonyl group in sugars (fructose versus glucose) and steric configuration of hydroxyl groups (glucose versus galactose) significantly affected yields of levulinic acid/ester (fructose>glucose>galactose). The dehydration of fructose to 5-(hydroxymethyl)furfural produces much less soluble polymer than that from glucose and galactose, which results in high yields of levulinic acid/ester from fructose. Anhydrate sugar such as levoglucosan tends to undergo the undesirable decomposition to form less levulinic acid/ester. Catalytic behaviors of the poly-sugars (sucrose, maltose, raffinose, β-cyclodextrins) were determined much by their basic units. However, their big molecular sizes create the steric hindrance that significantly affects their followed conversion over solid acid catalyst. Copyright © 2013 Elsevier Ltd. All rights reserved.

Amorphous Metal Polysulfides: Electrode Materials with Unique Insertion/Extraction Reactions.

PubMed

Sakuda, Atsushi; Ohara, Koji; Fukuda, Katsutoshi; Nakanishi, Koji; Kawaguchi, Tomoya; Arai, Hajime; Uchimoto, Yoshiharu; Ohta, Toshiaki; Matsubara, Eiichiro; Ogumi, Zempachi; Okumura, Toyoki; Kobayashi, Hironori; Kageyama, Hiroyuki; Shikano, Masahiro; Sakaebe, Hikari; Takeuchi, Tomonari

2017-07-05

A unique charge/discharge mechanism of amorphous TiS 4 is reported. Amorphous transition metal polysulfide electrodes exhibit anomalous charge/discharge performance and should have a unique charge/discharge mechanism: neither the typical intercalation/deintercalation mechanism nor the conversion-type one, but a mixture of the two. Analyzing the mechanism of such electrodes has been a challenge because fewer tools are available to examine the "amorphous" structure. It is revealed that the electrode undergoes two distinct structural changes: (i) the deformation and formation of S-S disulfide bonds and (ii) changes in the coordination number of titanium. These structural changes proceed continuously and concertedly for Li insertion/extraction. The results of this study provide a novel and unique model of amorphous electrode materials with significantly larger capacities.

Structural phase stability in nanocrystalline titanium to 161 GPa

DOE Office of Scientific and Technical Information (OSTI.GOV)

Velisavljevic, Nenad; Jacobsen, Matthew K.; Vohra, Yogesh K.

2014-09-16

Nanocrystalline titanium (nc-Ti) metal was investigated up to 161 GPa at room temperature using a diamond anvil cell. X-ray diffraction and electrical resistance techniques were used to investigate the compressibility and structural phase stability. nc-Ti is observed to undergo three structural phase transitions at high pressures, starting with α → ω at 10GPa and followed by ω → γ at 127GPa and γ → δ at 140GPa. The observed structural phase transitions, as well as compressibility, are consistent with previously reported values for coarse grained Ti (c-Ti). The high pressure experiments on nc-Ti samples do no show any significant variationmore » of the α → ω transition pressure under varying nonhydrostatic conditions. This is in sharp contrast to c-Ti, where a significant decrease in the α → ω transition pressure is observed under increasing nonhydrostatic conditions. As a result, this would indicate that the decrease in grain size in nano grained titanium makes the α → ω phase transition less sensitive to shear stresses as compared to bulk or c-Ti.« less

Gingival enlargement in orthodontic patients: Effect of treatment duration.

PubMed

Pinto, Alice Souza; Alves, Luana Severo; Zenkner, Júlio Eduardo do Amaral; Zanatta, Fabrício Batistin; Maltz, Marisa

2017-10-01

In this study, we aimed to assess the effect of the duration of fixed orthodontic treatment on gingival enlargement (GE) in adolescents and young adults. The sample consisted of 260 subjects (ages, 10-30 years) divided into 4 groups: patients with no fixed orthodontic appliances (G0) and patients undergoing orthodontic treatment for 1 year (G1), 2 years (G2), or 3 years (G3). Participants completed a structured questionnaire on sociodemographic characteristics and oral hygiene habits. Clinical examinations were conducted by a calibrated examiner and included the plaque index, the gingival index, and the Seymour index. Poisson regression models were used to assess the association between group and GE. We observed increasing means of plaque, gingivitis, and GE in G0, G1, and G2. No significant differences were observed between G2 and G3. Adjusted Poisson regression analysis showed that patients undergoing orthodontic treatment had a 20 to 28-fold increased risk for GE than did those without orthodontic appliances (G1, rate ratio [RR] = 20.2, 95% CI = 9.0-45.3; G2, RR = 27.0, 95% CI = 12.1-60.3; G3 = 28.1; 95% CI = 12.6-62.5). The duration of orthodontic treatment significantly influenced the occurrence of GE. Oral hygiene instructions and motivational activities should target adolescents and young adults undergoing orthodontic treatment. Copyright © 2017 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Prospective dynamic functional evaluation of gait and spinal balance following spinal fusion in adolescent idiopathic scoliosis.

PubMed

Lenke, L G; Engsberg, J R; Ross, S A; Reitenbach, A; Blanke, K; Bridwell, K H

2001-07-15

Prospective evaluation of gait and spinal-pelvic balance parameters in patients with adolescent idiopathic scoliosis undergoing a spinal fusion. To evaluate changes in gait and three-dimensional alignment and balance of the spine relative to the pelvis as a consequence of spinal fusion. Preoperative and postoperative spinal radiographs have been the major forms of outcome analysis of adolescent idiopathic scoliosis fusions. The use of optoelectronic analysis for posture and gait has gained acceptance recently. However, there is a paucity of data quantifying, comparing, and correlating structural and functional changes in patients undergoing scoliosis fusion surgery including upright posture and gait. Thirty patients with adolescent idiopathic scoliosis undergoing an instrumented spinal fusion were prospectively evaluated. Coronal and sagittal vertical alignment was evaluated on radiographs (CVA-R, SVA-R), during upright posture (CVA-P and SVA-P), and during gait (CVA-G, SVA-G). Transverse plane alignment was evaluated by the acromion-pelvis angle during gait. Gait speed was significantly decreased (P < 0.05) between preoperative (129 +/- 16 cm/sec) and 2-year postoperative (119 +/- 16 cm/sec) testing sessions. Decreasing gait speed was the result of significantly reduced cadence and decreased stride length. There were no significant differences for lower extremity kinematics over the entire gait cycle. Spinal-pelvic balance parameters showed significant improvement in mean CVA-R, CVA-G (P < 0.05), then unchanged CVA-P at 2 years postoperation. CVA-P was relatively unchanged while the mean CVA-G also showed significant improvement from preoperation (2.2 +/- 2.4 cm) to 2 years postoperation (1.3 +/- 1.3 cm)(P < 0.05). The mean SVA-R, SVA-P, and SVA-G were unchanged at 2 years postoperation (P > 0.05). The acromion-pelvis angle during gait at maximum shoulder rotation was statistically improved at 1 year (P = 0.002) and 2 years (P = 0.001) after surgery. Importantly, CVA-P correlated with CVA-G, and SVA-P correlated with SVA-G to the P < 0.05 level. Patients with adolescent idiopathic scoliosis undergoing spinal fusion show slightly decreased gait speed at 2 years postoperation without any change in lower extremity kinematics. Spinal-pelvic balance parameters are improved in the coronal plane and unchanged in the sagittal plane radiographically and during standing posture and gait. Transverse plane parameters also are improved at maximum shoulder rotation during gait.

Design and Manufacture of Conical Shell Structures Using Prepreg Laminates

NASA Astrophysics Data System (ADS)

Khakimova, Regina; Burau, Florian; Degenhardt, Richard; Siebert, Mark; Castro, Saullo G. P.

2016-06-01

The design and manufacture of unstiffened composite conical structures is very challenging, as the variation of the fiber orientations, lay-up and the geometry of the ply pieces have a significant influence on the thickness imperfections and ply angle deviations imprinted to the final part. This paper deals with the manufacture of laminated composite cones through the prepeg/autoclave process. The cones are designed to undergo repetitive buckling tests without accumulating permanent damage. The aim is to define a process that allows the control of fiber angle deviations and the removal of thickness imperfections generated from gaps and overlaps between ply pieces. Ultrasonic scan measurements are used to proof the effectiveness of the proposed method.

The role of electrostatics and temperature on morphological transitions of hydrogel nanostructures self-assembled by peptide amphiphiles via molecular dynamics simulations.

PubMed

Fu, Iris W; Markegard, Cade B; Chu, Brian K; Nguyen, Hung D

2013-10-01

Smart biomaterials that are self-assembled from peptide amphiphiles (PA) are known to undergo morphological transitions in response to specific physiological stimuli. The design of such customizable hydrogels is of significant interest due to their potential applications in tissue engineering, biomedical imaging, and drug delivery. Using a novel coarse-grained peptide/polymer model, which has been validated by comparison of equilibrium conformations from atomistic simulations, large-scale molecular dynamics simulations are performed to examine the spontaneous self-assembly process. Starting from initial random configurations, these simulations result in the formation of nanostructures of various sizes and shapes as a function of the electrostatics and temperature. At optimal conditions, the self-assembly mechanism for the formation of cylindrical nanofibers is deciphered involving a series of steps: (1) PA molecules quickly undergo micellization whose driving force is the hydrophobic interactions between alkyl tails; (2) neighboring peptide residues within a micelle engage in a slow ordering process that leads to the formation of β-sheets exposing the hydrophobic core; (3) spherical micelles merge together through an end-to-end mechanism to form cylindrical nanofibers that exhibit high structural fidelity to the proposed structure based on experimental data. As the temperature and electrostatics vary, PA molecules undergo alternative kinetic mechanisms, resulting in the formation of a wide spectrum of nanostructures. A phase diagram in the electrostatics-temperature plane is constructed delineating regions of morphological transitions in response to external stimuli. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Widespread signatures of local mRNA folding structure selection in four Dengue virus serotypes

PubMed Central

2015-01-01

Background It is known that mRNA folding can affect and regulate various gene expression steps both in living organisms and in viruses. Previous studies have recognized functional RNA structures in the genome of the Dengue virus. However, these studies usually focused either on the viral untranslated regions or on very specific and limited regions at the beginning of the coding sequences, in a limited number of strains, and without considering evolutionary selection. Results Here we performed the first large scale comprehensive genomics analysis of selection for local mRNA folding strength in the Dengue virus coding sequences, based on a total of 1,670 genomes and 4 serotypes. Our analysis identified clusters of positions along the coding regions that may undergo a conserved evolutionary selection for strong or weak local folding maintained across different viral variants. Specifically, 53-66 clusters for strong folding and 49-73 clusters for weak folding (depending on serotype) aggregated of positions with a significant conservation of folding energy signals (related to partially overlapping local genomic regions) were recognized. In addition, up to 7% of these positions were found to be conserved in more than 90% of the viral genomes. Although some of the identified positions undergo frequent synonymous / non-synonymous substitutions, the selection for folding strength therein is preserved, and thus cannot be trivially explained based on sequence conservation alone. Conclusions The fact that many of the positions with significant folding related signals are conserved among different Dengue variants suggests that a better understanding of the mRNA structures in the corresponding regions may promote the development of prospective anti- Dengue vaccination strategies. The comparative genomics approach described here can be employed in the future for detecting functional regions in other pathogens with very high mutations rates. PMID:26449467

Investigation of the redox-dependent modulation of structure and dynamics in human cytochrome c

DOE Office of Scientific and Technical Information (OSTI.GOV)

Imai, Mizue; Saio, Tomohide; Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810

2016-01-22

Redox-dependent changes in the structure and dynamics of human cytochrome c (Cyt c) were investigated by solution NMR. We found significant structural changes in several regions, including residues 23–28 (loop 3), which were further corroborated by chemical shift differences between the reduced and oxidized states of Cyt c. These differences are essential for discriminating redox states in Cyt c by cytochrome c oxidase (CcO) during electron transfer reactions. Carr-Purcell-Meiboom-Gill (CPMG) relaxation dispersion experiments identified that the region around His33 undergoes conformational exchanges on the μs-ms timescale, indicating significant redox-dependent structural changes. Because His33 is not part of the interaction sitemore » for CcO, our data suggest that the dynamic properties of the region, which is far from the interaction site for CcO, contribute to conformational changes during electron transfer to CcO. - Highlights: • Solution structure and dynamics analysis for human Cyt c by NMR. • Structural changes responsible for the discrimination of the redox state in Cyt c. • Conformational exchange in the region outside of the interaction site for CcO. • Less flexibility and rigid structure of the interaction site on Cyt c for CcO.« less

Effects of diabetes and hypertension on structure and distensibilty of human small coronary arteries.

PubMed

Lynch, Fiona M; Izzard, Ashley S; Austin, Clare; Prendergast, Brian; Keenan, Daniel; Malik, Rayaz A; Heagerty, Anthony M

2012-02-01

Previous studies have demonstrated that hypertension and diabetes induce significant structural remodelling of resistance arteries from various vascular beds. The hypothesis of this study is that structural alterations of small coronary arteries may occur during hypertension and diabetes. This study is the first to compare human coronary small resistance artery structure from normotensive and hypertensive patients, with and without diabetes undergoing coronary arterial bypass graft surgery. Small arteries were dissected from the atrial appendage removed from nondiabetic normotensive patients, nondiabetic hypertension and diabetic normotensive patients and hypertensive diabetic patients. Arteries were mounted in a pressure myograph and lumen diameter and wall thickness were measured across the pressure range of 3-100 mmHg to assess vessel structure and distensibility. There were no significant differences in the lumen diameter, wall thickness, wall-to-lumen ratio and cross-sectional area of arteries in all groups. Arteries from nondiabetic patients with hypertension demonstrated decreased distensibility compared with nondiabetic normotensive patients. There is no difference in distensibility between vessels from diabetic hypertensive patients and either diabetic or nondiabetic normotensive patients. Neither diabetes nor hypertension appears to have influenced arterial structure which may indicate that successful treatment of hypertension is associated with normal vascular structure in coronary small arteries.

Structural Dynamics and Activity of Nanocatalysts Inside Fuel Cells by in-operando Atomic Pair Distribution Studies

NASA Astrophysics Data System (ADS)

Prasai, Binay

We present the results from a study aimed at clarifying the relationship between the atomic structure and activity of nanocatalysts for chemical reactions driving fuel cells, such as the oxygen reduction reaction (ORR). Using in-operando high-energy X-ray diffraction we tracked the evolution of the atomic structure and activity of noble metal-transition metal(NM-TM) nanocatalysts for ORR as they function at the cathode of a fully operational proton exchange membrane fuel cell (PEMFC). Data were analyzed in terms of atomic pair distribution functions and compared to the current output of the PEMFC, which was also recorded during the experiments. The comparison revealed that under actual operating conditions, NM-TM nanocatalysts can undergo structural changes that differ significantly in both length-scale and dynamics and so can suffer losses in their ORR activity that differ significantly in both character and magnitude. Therefore, we argue that strategies for reducing ORR activity losses should implement steps for achieving control not only over the length but also over the time-scale of the structural changes of NM-TM NPs that indeed occur during PEMFC operation.

Hemin/G-quadruplex structure and activity alteration induced by magnesium cations.

PubMed

Kosman, J; Juskowiak, B

2016-04-01

The influence of metal cations on G-quadruplex structure and peroxidase-mimicking DNAzyme activity was investigated. Experiments revealed a significant role of magnesium ion, which in the presence of potassium cation influenced DNAzyme activity. This ability has been associated with alteration of G-quadruplex topology and consequently affinity to bind hemin molecule. It has been demonstrated that G-quadruplex based on PS2.M sequence under these conditions formed parallel topology, which exhibited lower activity than that observed in standard potassium-containing solution. On the other hand DNAzyme/magnesium ion system based on telomeric sequence, which did not undergo significant structural changes, exhibited higher peroxidase activity upon magnesium ion addition. In both cases, the stabilization effect of magnesium cations on G-quadruplex structure was observed. The mechanism of DNAzyme activity alteration by magnesium ion can be explained by its influence on the pKa value of DNAzyme. Magnesium ion decreased pKa for PS2.M based system but increased it for telomeric DNAzyme. Magnesium cation effect on G-quadruplex structure as well as DNAzyme activity is particularly important since this ion is one of the most common metal cations in biological samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Native State Volume Fluctuations in Proteins as a Mechanism for Dynamic Allostery.

PubMed

Law, Anthony B; Sapienza, Paul J; Zhang, Jun; Zuo, Xiaobing; Petit, Chad M

2017-03-15

Allostery enables tight regulation of protein function in the cellular environment. Although existing models of allostery are firmly rooted in the current structure-function paradigm, the mechanistic basis for allostery in the absence of structural change remains unclear. In this study, we show that a typical globular protein is able to undergo significant changes in volume under native conditions while exhibiting no additional changes in protein structure. These native state volume fluctuations were found to correlate with changes in internal motions that were previously recognized as a source of allosteric entropy. This finding offers a novel mechanistic basis for allostery in the absence of canonical structural change. The unexpected observation that function can be derived from expanded, low density protein states has broad implications for our understanding of allostery and suggests that the general concept of the native state be expanded to allow for more variable physical dimensions with looser packing.

Multidirectional Efficacy of Biologically Active Nitro Compounds Included in Medicines.

PubMed

Olender, Dorota; Żwawiak, Justyna; Zaprutko, Lucjusz

2018-05-29

The current concept in searching for new bioactive products, including mainly original active substances with potential application in pharmacy and medicine, is based on compounds with a previously determined structure, well-known properties, and biological activity profile. Nowadays, many commonly used drugs originated from natural sources. Moreover, some natural materials have become the source of leading structures for processing further chemical modifications. Many organic compounds with great therapeutic significance have the nitro group in their structure. Very often, nitro compounds are active substances in many well-known preparations belonging to different groups of medicines that are classified according to their pharmacological potencies. Moreover, the nitro group is part of the chemical structure of veterinary drugs. In this review, we describe many bioactive substances with the nitro group, divided into ten categories, including substances with exciting activity and that are currently undergoing clinical trials.

Structural basis for the facilitative diffusion mechanism by SemiSWEET transporter

NASA Astrophysics Data System (ADS)

Lee, Yongchan; Nishizawa, Tomohiro; Yamashita, Keitaro; Ishitani, Ryuichiro; Nureki, Osamu

2015-01-01

SWEET family proteins mediate sugar transport across biological membranes and play crucial roles in plants and animals. The SWEETs and their bacterial homologues, the SemiSWEETs, are related to the PQ-loop family, which is characterized by highly conserved proline and glutamine residues (PQ-loop motif). Although the structures of the bacterial SemiSWEETs were recently reported, the conformational transition and the significance of the conserved motif in the transport cycle have remained elusive. Here we report crystal structures of SemiSWEET from Escherichia coli, in the both inward-open and outward-open states. A structural comparison revealed that SemiSWEET undergoes an intramolecular conformational change in each protomer. The conserved PQ-loop motif serves as a molecular hinge that enables the ‘binder clip-like’ motion of SemiSWEET. The present work provides the framework for understanding the overall transport cycles of SWEET and PQ-loop family proteins.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Law, Anthony B.; Sapienza, Paul J.; Zhang, Jun

Allostery enables tight regulation of protein function in the cellular environment. While existing models of allostery are firmly rooted in the current structure-function paradigm, the mechanistic basis for allostery in the absence of structural change remains unclear. In this study, we show that a typical globular protein is able to undergo significant changes in volume under native conditions while exhibiting no additional changes in protein structure. These native state volume fluctuations were found to correlate with changes in internal motions that were previously recognized as a source of allosteric entropy. This finding offers a novel mechanistic basis for allostery inmore » the absence of canonical structural change. As a result, the unexpected observation that function can be derived from expanded, low density protein states has broad implications for our understanding of allostery and suggests that the general concept of the native state be expanded to allow for more variable physical dimensions with looser packing.« less

What makes the difference in perovskite titanates?

NASA Astrophysics Data System (ADS)

Bussmann-Holder, Annette; Roleder, Krystian; Ko, Jae-Hyeon

2018-06-01

We have investigated in detail the lattice dynamics of five different perovskite titanates ATiO3 (A = Ca, Sr, Ba, Pb, Eu) where the A sites are occupied by +2 ions. In spite of the largely ionic character of these ions, the properties of these compounds differ substantially. They range from order/disorder like, to displacive ferroelectric, quantum paraelectric, and antiferromagnetic. All compounds crystallize in the cubic structure at high temperature and undergo structural phase transitions to tetragonal symmetry, partly followed by further transitions to lower symmetries. Since the TiO6 moiety is the essential electronic and structural unit, the question arises, what makes the significant difference between them. It is shown that the lattice dynamics of these compounds are very different, and that mode-mode coupling effects give rise to many distinct properties. In addition, the oxygen ion nonlinear polarizability plays a key role since it dominates the anharmonicity of these perovskites and determines the structural instability.

Detailed fetal anatomy assessment in the first trimester at 11, 12 and 13 weeks of gestation.

PubMed

Luchi, Carlo; Schifano, Martina; Sacchini, Clara; Nanini, Chiara; Sceusa, Francesca; Capriello, Patrizio; Genazzani, Andrea R

2012-06-01

The aim of the present observational study was to evaluate the feasibility of a morphological scan and determine the detection rate of fetal organs, structures and systems in the first trimester of pregnancy. 977 single pregnant women attending our Fetal Medicine Section to undergo first trimester screening for aneuploidies were enrolled and divided into three groups depending on gestational age and crown-rump-length measurement. Scans targeted on a total of 26 fetal anatomical structures were performed by a single operator. The overall detection rate was 96% at 11 weeks and reached 100% at 12 and 13 weeks, with a significant statistical difference between 11 and 12/13 weeks for the majority of the investigated fetal anatomical structures. Evaluation of most part of the fetal anatomical structures is feasible with high accuracy in the first trimester. Visualization of the majority of the targeted fetal organs improves from 11 to 13 weeks.

How Conformational Dynamics of DNA Polymerase Select Correct Substrates: Experiments and Simulations

PubMed Central

Kirmizialtin, Serdal; Nguyen, Virginia; Johnson, Kenneth A.; Elber, Ron

2012-01-01

Summary Nearly every enzyme undergoes a significant change in structure after binding it’s substrate. New experimental and theoretical analyses of the role of changes in HIV reverse transcriptase structure in selecting a correct substrate are presented. Atomically detailed simulations using the Milestoning method predict a rate and free energy profile of the conformational change commensurate with experimental data. A large conformational change occurring on a ms timescale locks the correct nucleotide at the active site, but promotes release of a mismatched nucleotide. The positions along the reaction coordinate that decide the yield of the reaction are not determined by the chemical step. Rather, the initial steps of weak substrate binding and protein conformational transition significantly enrich the yield of a reaction with a correct substrate, while the same steps diminish the reaction probability of an incorrect substrate. PMID:22483109

Embedding memories in colloidal gels though oscillatory shear

NASA Astrophysics Data System (ADS)

Schwen, Eric; Ramaswamay, Meera; Jan, Linda; Cheng, Chieh-Min; Cohen, Itai

While gels are ubiquitous in applications from food products to filtration, their mechanical properties are usually determined by self-assembly. We use oscillatory shear to train colloidal gels, embedding memories of the training protocol in rheological responses such as the yield strain and the gel network structures. When our gels undergo shear, the particles are forced to rearrange until they organize into structures that can locally undergo reversible shear cycles. We utilize a high-speed confocal microscope and a shear cell to image a colloidal gel while simultaneously straining the gel and measuring its shear stresses. By comparing stroboscopic images of the gel, we quantify the decrease in particle rearrangement as the gel develops reversible structures. We analyze and construct a model for the rates at which different regions in the gel approach reversible configurations. Through characterizing the gel network, we determine the structural origins of these shear training memories in gels. These results may allow us to use shear training protocols to produce gels with controllable yield strains and to better understand changes in the microstructure and rheology of gels that undergo repeated shear through mixing or flowing. This research was supported in part by NSF CBET 1509308 and Xerox Corporation.

Study of improved modeling and solution procedures for nonlinear analysis. [aircraft-like structures

NASA Technical Reports Server (NTRS)

Kamat, M. P.

1979-01-01

An evaluation of the ACTION computer code on an aircraft like structure is presented. This computer program proved adequate in predicting gross response parameters in structures which undergo severe localized cross sectional deformations.

Assessing infertility-related stress: the factor structure of the Fertility Problem Inventory in Italian couples undergoing infertility treatment.

PubMed

Donarelli, Zaira; Gullo, Salvatore; Lo Coco, Gianluca; Marino, Angelo; Scaglione, Piero; Volpes, Aldo; Allegra, Adolfo

2015-01-01

The factor structure of the Fertility Problem Inventory (FPI) and its invariance across gender were examined in Italian couples undergoing infertility treatment. About 1000 subjects (both partners of 500 couples) completed two questionnaires prior to commencing infertility treatment at a private Clinic in Palermo, Italy. Confirmatory Factor Analysis demonstrated that the original factor structure of the FPI was partially confirmed. Two correlated factors (Infertility Life Domains and Importance of Parenthood) were obtained via a post hoc Exploratory Factor Analysis. Finally, the invariance of this factor structure across gender was confirmed. The study supported the relevance of two interrelated factors specific to infertility stress which could help clinicians to focus on the core infertility-related stress domains of infertile couples.

Studies of the spin Hamiltonian parameters and local structure for ZnO:Cu2+.

PubMed

Wu, Shao-Yi; Wei, Li-Hua; Zhang, Zhi-Hong; Wang, Xue-Feng; Hu, Yue-Xia

2008-12-15

The spin Hamiltonian parameters (the g factors and the hyperfine structure constants) and local structure for ZnO:Cu2+ are theoretically studied from the perturbation formulas of these parameters for a 3d9 ion under trigonally distorted tetrahedra. The ligand orbital and spin-orbit coupling contributions are taken into account from the cluster approach due to the significant covalency of the [CuO4](6-) cluster. According to the investigations, the impurity Cu2+ is suggested not to locate on the ideal Zn2+ site in ZnO but to undergo a slight outward displacement (approximately 0.01 angstroms) away from the ligand triangle along C3 axis. The calculated spin Hamiltonian parameters are in good agreement with the observed values. The validity of the above impurity displacement is also discussed.

[The spectrum studies of structure characteristics in magma contact metamorphic coal].

PubMed

Wu, Dun; Sun, Ruo-Yu; Liu, Gui-Jian; Yuan, Zi-Jiao

2013-10-01

The structural parameters evolution of coal due to the influence of intrusions of hot magma was investigated and analyzed. X-ray diffraction and laser confocal microscope Raman spectroscopy were used to test and analyze 4 coal samples undergoing varying contact-metamorphism by igneous magmas in borehole No. 13-4 of Zhuji coal mine, Huainan coalfield. The result showed that coal XRD spectrum showed higher background intensity, with the 26 degrees and 42 degrees nearby apparent graphite diffraction peak. Two significant vibration peaks of coal Raman spectra were observed in the 1 000-2 000 cm(-1) frequency range: broad "D" peak at 1 328-1 369 cm(-1) and sharp "G" peak at 1 564-1 599 cm(-1). With the influence of magma intrusion, the relationship between coal structural parameters and coal ranks was excellent.

[Protective effects of micro-encapsulated Bifidobacteria on gut barrier after hemorrhagic shock and resuscitation: experiment with rats].

PubMed

Ruan, Xiang-cai; Wang, Shen-ming; Shi, Han-ping; Li, Xiao-xi; Xia, Feng-geng; Ming, Fei-ping

2009-03-10

To investigate the effects of micro-encapsulated bifidobacteria on gut barrier and bacterial translocation after hemorrhagic shock and resuscitation. Sprague-Dawley rats were divided into 6 groups: PBS+sham shock group fed with PBS for 7 days and then undergoing sham shock, bifidobacteria+sham shock group fed with bifidobacteria (10(9) cfu/d) for 7 days and then undergoing sham shock, micro-encapsulated bifidobacteria+sham shock group, fed with micro-encapsulated bifidobacteria (10(9) cfu/d) for 7 days and then undergoing sham shock, PBS+hemorrhagic shock group fed with PBS for 7 days and then undergoing hemorrhagic shock, bifidobacteria+shock group fed with bifidobacteria for 7 days and then undergoing hemorrhagic shock, and micro-encapsulated bifidobacteria+shock group, fed with micro-encapsulated bifidobacteria for 7 days and then undergoing hemorrhagic shock. Three hours after resuscitation laparotomy was performed, distal cecum was resected to undergo bacteriological analysis of the cecal content, mesenteric lymph nodes (MLNs), a liver lobe, and the middle part of spleen were resected to undergo bacterial culture for bacterial translocation, and the terminal ileum was resected to observe the villous damage. There was no significant difference in the amount of blood loss among the 3 hemorrhagic shock groups. The amounts of aerobes in cecum of the bifidobacteria+shock and micro-encapsulated bifidobacteria+shock groups, especially that of the latter group, were significantly lower than that of the PBS+shock group. The amounts of anaerobes and the amounts of bifidobacteria in cecum of the bifidobacteria+shock group and micro-encapsulated bifidobacteria+shock group, especially those of the latter group, were significantly higher than those of the PBS+shock group. No bacterial translocation to liver was observed in all groups. The magnitudes of total aerobes translocation in spleen of the bifidobacteria+shock and encapsulated bifidobacteria+shock groups were significantly lower than that of the PBS+shock group, however, there were not significant differences in the translocation in the MLN of total aerobes ad bifidobacteria among different groups. The percentage of ileal villous damage of the bifidobacteria+shock and encapsulated bifidobacteria+shock groups were significantly lower than that of the PBS+shock group. Bifidobacteria effectively protects the gut barrier, reduces bacterial translocation from the gut after hemorrhagic shock and resuscitation. And micro-encapsulated Bifidobacteria can enhance those effects further.

Meta-Analysis of Postoperative Outcome Parameters Comparing Descemet Membrane Endothelial Keratoplasty Versus Descemet Stripping Automated Endothelial Keratoplasty.

PubMed

Pavlovic, Ivana; Shajari, Mehdi; Herrmann, Eva; Schmack, Ingo; Lencova, Anna; Kohnen, Thomas

2017-12-01

This meta-analysis compares Descemet membrane endothelial keratoplasty (DMEK) with Descemet stripping automated endothelial keratoplasty (DSAEK) to evaluate their strength and weakness profiles. Meta-analysis. We performed a meta-analysis and searched the peer-reviewed literature in PubMed, Cochrane Library, Web of Science, and Embase following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Prospective and retrospective trials performing and comparing DMEK and DSAEK were included. Effects were calculated as odds ratios or standardized mean differences. A total of 11 studies with a total of 723 eyes (350 DMEK and 373 DSAEK) were included. No significant difference was found regarding the total detachment rate, graft failure, and rejection. One of 340 eyes undergoing DMEK showed total detachment and 5 of 363 eyes undergoing DSAEK showed total detachment (P = 0.28). Six of 280 eyes undergoing DMEK showed graft failure; 1 of 313 eyes undergoing DSAEK developed this complication (P = 0.18). No rejection was observed in 158 eyes undergoing DMEK; 4 cases of rejection occurred in 196 eyes undergoing DSAEK (P = 0.37). No significant difference was found regarding endothelial cell loss (P = 0.48). There was a significantly higher partial detachment rate with DMEK: 88 of 340 eyes undergoing DMEK showed partial detachment; 16 of 363 eyes undergoing DSAEK showed this complication (P < 0.00001). DMEK was superior in best-corrected visual acuity after 6 months (P < 0.001), subjective evaluation of visual acuity (P = 0.001), patient satisfaction (P < 0.001), and was the method preferred by patients (P = 0.001). DMEK and DSAEK have a similar complication profile. However, the superiority in the visual outcome and patient satisfaction makes DMEK the preferred option for most patients.

Patterns of coordinated cortical remodeling during adolescence and their associations with functional specialization and evolutionary expansion.

PubMed

Sotiras, Aristeidis; Toledo, Jon B; Gur, Raquel E; Gur, Ruben C; Satterthwaite, Theodore D; Davatzikos, Christos

2017-03-28

During adolescence, the human cortex undergoes substantial remodeling to support a rapid expansion of behavioral repertoire. Accurately quantifying these changes is a prerequisite for understanding normal brain development, as well as the neuropsychiatric disorders that emerge in this vulnerable period. Past accounts have demonstrated substantial regional heterogeneity in patterns of brain development, but frequently have been limited by small samples and analytics that do not evaluate complex multivariate imaging patterns. Capitalizing on recent advances in multivariate analysis methods, we used nonnegative matrix factorization (NMF) to uncover coordinated patterns of cortical development in a sample of 934 youths ages 8-20, who completed structural neuroimaging as part of the Philadelphia Neurodevelopmental Cohort. Patterns of structural covariance (PSCs) derived by NMF were highly reproducible over a range of resolutions, and differed markedly from common gyral-based structural atlases. Moreover, PSCs were largely symmetric and showed correspondence to specific large-scale functional networks. The level of correspondence was ordered according to their functional role and position in the evolutionary hierarchy, being high in lower-order visual and somatomotor networks and diminishing in higher-order association cortex. Furthermore, PSCs showed divergent developmental associations, with PSCs in higher-order association cortex networks showing greater changes with age than primary somatomotor and visual networks. Critically, such developmental changes within PSCs were significantly associated with the degree of evolutionary cortical expansion. Together, our findings delineate a set of structural brain networks that undergo coordinated cortical thinning during adolescence, which is in part governed by evolutionary novelty and functional specialization.

Topology optimization of hyperelastic structures using a level set method

NASA Astrophysics Data System (ADS)

Chen, Feifei; Wang, Yiqiang; Wang, Michael Yu; Zhang, Y. F.

2017-12-01

Soft rubberlike materials, due to their inherent compliance, are finding widespread implementation in a variety of applications ranging from assistive wearable technologies to soft material robots. Structural design of such soft and rubbery materials necessitates the consideration of large nonlinear deformations and hyperelastic material models to accurately predict their mechanical behaviour. In this paper, we present an effective level set-based topology optimization method for the design of hyperelastic structures that undergo large deformations. The method incorporates both geometric and material nonlinearities where the strain and stress measures are defined within the total Lagrange framework and the hyperelasticity is characterized by the widely-adopted Mooney-Rivlin material model. A shape sensitivity analysis is carried out, in the strict sense of the material derivative, where the high-order terms involving the displacement gradient are retained to ensure the descent direction. As the design velocity enters into the shape derivative in terms of its gradient and divergence terms, we develop a discrete velocity selection strategy. The whole optimization implementation undergoes a two-step process, where the linear optimization is first performed and its optimized solution serves as the initial design for the subsequent nonlinear optimization. It turns out that this operation could efficiently alleviate the numerical instability and facilitate the optimization process. To demonstrate the validity and effectiveness of the proposed method, three compliance minimization problems are studied and their optimized solutions present significant mechanical benefits of incorporating the nonlinearities, in terms of remarkable enhancement in not only the structural stiffness but also the critical buckling load.

A finite-difference method for the variable coefficient Poisson equation on hierarchical Cartesian meshes

NASA Astrophysics Data System (ADS)

Raeli, Alice; Bergmann, Michel; Iollo, Angelo

2018-02-01

We consider problems governed by a linear elliptic equation with varying coefficients across internal interfaces. The solution and its normal derivative can undergo significant variations through these internal boundaries. We present a compact finite-difference scheme on a tree-based adaptive grid that can be efficiently solved using a natively parallel data structure. The main idea is to optimize the truncation error of the discretization scheme as a function of the local grid configuration to achieve second-order accuracy. Numerical illustrations are presented in two and three-dimensional configurations.

White dwarf evolution - Cradle-to-grave constraints via pulsation

NASA Technical Reports Server (NTRS)

Kawaler, Steven D.

1990-01-01

White dwarf evolution, particularly in the early phases, is not very strongly constrained by observation. Fortunately, white dwarfs undergo nonradial pulsation in three distinct regions of the H-R diagram. These pulsations provide accurate masses, surface compositional structure and rotation velocities, and help constrain other important physical properties. We demonstrate the application of the tools of stellar seismology to white dwarf evolution using the hot white dwarf star PG 1159-035 and the cool DAV (or ZZ Ceti) stars as examples. From pulsation studies, significant challenges to the theory of white dwarf evolution emerge.

Surfing the wave, cycle, life history, and genes/proteins expressed by testicular germ cells. Part 2: changes in spermatid organelles associated with development of spermatozoa.

PubMed

Hermo, Louis; Pelletier, R-Marc; Cyr, Daniel G; Smith, Charles E

2010-04-01

Spermiogenesis is a long process whereby haploid spermatids derived from the meiotic divisions of spermatocytes undergo metamorphosis into spermatozoa. It is subdivided into distinct steps with 19 being identified in rats, 16 in mouse and 8 in humans. Spermiogenesis extends over 22.7 days in rats and 21.6 days in humans. In this part, we review several key events that take place during the development of spermatids from a structural and functional point of view. During early spermiogenesis, the Golgi apparatus forms the acrosome, a lysosome-like membrane bound organelle involved in fertilization. The endoplasmic reticulum undergoes several topographical and structural modifications including the formation of the radial body and annulate lamellae. The chromatoid body is fully developed and undergoes structural and functional modifications at this time. It is suspected to be involved in RNA storing and processing. The shape of the spermatid head undergoes extensive structural changes that are species-specific, and the nuclear chromatin becomes compacted to accommodate the stream-lined appearance of the sperm head. Microtubules become organized to form a curtain or manchette that associates with spermatids at specific steps of their development. It is involved in maintenance of the sperm head shape and trafficking of proteins in the spermatid cytoplasm. During spermiogenesis, many genes/proteins have been implicated in the diverse dynamic events occurring at this time of development of germ cells and the absence of some of these have been shown to result in subfertility or infertility. Copyright 2009 Wiley-Liss, Inc.

Red blood cell storage duration and long-term mortality in patients undergoing cardiac intervention: a Danish register study.

PubMed

Dencker, D; Pedersen, F; Engstrøm, T; Schroeder, T V; Lönn, L; Johansson, P I; De Backer, O

2017-08-01

To study the effect of red blood cell (RBC) storage duration on long-term mortality in patients undergoing cardiac intervention. RBCs undergo numerous structural and functional changes during storage. Observational studies have assessed the association between RBC storage duration and patient outcomes with conflicting results. Between January 2006 and December 2014, 82 408 patients underwent coronary angiography. Of these, 1856 patients received one to four RBC units within 30 days after this procedure. Patients were allocated according to length of RBC storage duration: short-term (≤11 days), intermediate (IM)-term (12-23 days) and long-term (≥24 days). The study endpoints were 30-day and long-term all-cause mortality. A total of 4168 RBC units were given to 1856 patients. The mean RBC storage duration was 8.5 ± 2.1, 17.7 ± 3.4 and 29.9 ± 3.4 days in the short-term, IM-term and long-term storage groups, respectively. There was no difference in baseline characteristics between the groups. The long-term storage group received significantly more units (2.4 ± 1.0 units) as compared to the short-term (2.0 ± 1.0 units; P < 0.001) and IM-term storage group (2.2 ± 1.0 units; P < 0.01). In the survival analysis, there was no significant difference in all-cause mortality between the groups (log-rank: 0.509 for 30-days mortality; 0.493 for 5-year mortality). Additional stratified analysis demonstrated no association between RBC storage duration and long-term mortality. This study did not find an association between RBC storage duration and 30-days or long-term mortality in patients undergoing cardiac intervention. © 2017 British Blood Transfusion Society.

Tapered structure construction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Eric D.; Takata, Rosalind K.; Slocum, Alexander H.

Feeding stock used to form a tapered structure into a curving device such that each point on the stock undergoes rotational motion about a peak location of the tapered structure; and the stock meets a predecessor portion of stock along one or more adjacent edges.

Should patients with asymptomatic significant carotid stenosis undergo simultaneous carotid and cardiac surgery?

PubMed Central

Ogutu, Peter; Werner, Raphael; Oertel, Frank; Beyer, Michael

2014-01-01

A best evidence topic in cardiovascular surgery was written according to a structured protocol. The question addressed was whether patients with severe asymptomatic carotid and coronary artery diseases should undergo simultaneous carotid endarterectomy (CEA) and coronary artery bypass grafting (CABG). A total of 624 papers were found using the reported search, of which 20 represent the best evidence to answer the clinical question. The author, journal, date and country of publication, patient group studied, study type, relevant outcomes, results and study results of these papers are tabulated. Previous cohort studies showed mixed results, while advocating for the necessity of a randomized controlled trial (RCT). A recent RCT showed that patients undergoing prophylactic or simultaneous CEA + CABG had lower rates of stroke (0%) compared with delayed CEA 1–3 months after CABG (7.7%), without significant perioperative mortality difference. This study included patients with unilateral severe (>70%) asymptomatic carotid stenosis requiring CABG. An earlier partly randomized trial also showed better outcomes for patients undergoing simultaneous procedures (P = 0.045). Interestingly, systematic reviews previously failed to show compelling evidence supporting prophylactic CEA. This could be partly due to the fact that these reviews collectively analyse different cohort qualities. Neurological studies have, however, shown reduced cognitive and phonetic quality and function in patients with unilateral and bilateral asymptomatic carotid artery stenosis. Twenty-one RCTs comparing lone carotid artery stenting (CAS) and CEA informed the American Heart Association guidelines, which declared CAS comparable with CEA for symptomatic and asymptomatic carotid stenosis (CS). However, the risk of death/stroke for CAS alone is double that for CEA alone in the acute phase following onset of symptoms, while CEA alone is associated with a doubled risk of myocardial infarction. There is, however, no significant difference for combined 30-day risk of death/stroke/myocardial infarction. Outcomes of hybrid or simultaneous CAS/CABG procedures show comparable results, albeit from rather small cohorts. While current evidence leans towards simultaneous CEA/CABG, the emergence of hybrid operating theatres in various institutions may allow larger cohorts with subsequent significant data on simultaneous CAS/CABG. A randomized controlled trial comparing both approaches would be crucial in informing future updates of existing guidelines. PMID:24368551

Double-walled silicon nanotubes: an ab initio investigation

NASA Astrophysics Data System (ADS)

Lima, Matheus P.

2018-02-01

The synthesis of silicon nanotubes realized in the last decade demonstrates multi-walled tubular structures consisting of Si atoms in {{sp}}2 and the {{sp}}3 hybridizations. However, most of the theoretical models were elaborated taking as the starting point {{sp}}2 structures analogous to carbon nanotubes. These structures are unfavorable due to the natural tendency of the Si atoms to undergo {{sp}}3. In this work, through ab initio simulations based on density functional theory, we investigated double-walled silicon nanotubes proposing layered tubes possessing most of the Si atoms in an {{sp}}3 hybridization, and with few {{sp}}2 atoms localized at the outer wall. The lowest-energy structures have metallic behavior. Furthermore, the possibility to tune the band structure with the application of a strain was demonstrated, inducing a metal-semiconductor transition. Thus, the behavior of silicon nanotubes differs significantly from carbon nanotubes, and the main source of the differences is the distortions in the lattice associated with the tendency of Si to make four chemical bonds.

Structural Insights of Glucan Phosphatase Dynamics using Amide Hydrogen/Deuterium Exchange Mass Spectrometry

PubMed Central

Hsu, Simon; Kim, Youngjun; Li, Sheng; Durrant, Eric S.; Pace, Rachel M.; Woods, Virgil L.; Gentry, Matthew S.

2009-01-01

Laforin and Starch Excess 4 (SEX4) are founding members of a class of phosphatases that dephosphorylate phosphoglucans. Each protein contains a carbohydrate binding module (CBM) and a dual specificity phosphatase (DSP) domain. The gene encoding laforin is mutated in a fatal neurodegenerative disease called Lafora disease (LD). In the absence of laforin function, insoluble glucans accumulate that are hyperphosphorylated and exhibit sparse branching. It is hypothesized that these accumulations trigger the neurodegeneration and premature death of LD patients. We recently demonstrated that laforin removes phosphate from phosphoglucans and hypothesized that this function inhibits insoluble glucan accumulation. Loss of SEX4 function in plants yields a similar cellular phenotype; cells accumulate an excess amount of insoluble, hyperphosphorylated glucans. While multiple groups have shown that these phosphatases dephosphorylate phosphoglucans, there is no structure of a glucan phosphatase and little is known about the mechanism whereby they perform this action. We utilized hydrogen-deuterium exchange mass spectrometry (DXMS) and structural modeling to probe the conformational and structural dynamics of the glucan phosphatase SEX4. We found that the enzyme does not undergo a global conformational change upon glucan binding, but instead undergoes minimal rearrangement upon binding. The CBM undergoes increased protection from deuteration when bound to glucans, confirming its role in glucan binding. More interestingly, we identified structural components of the DSP that also undergo increased protection from deuteration upon glucan addition. To determine the position of these regions, we generated a homology model of the SEX4 DSP. The homology model shows that all of these regions are adjacent the DSP active site. Therefore, our results suggest that these regions of the DSP participate in presenting the phosphoglucan to the active site and provide the first structural analysis and mode of action of this unique class of phosphatases. PMID:19754155

UV-damaged DNA binding protein-1 and de-etiolated-1 regulate golden 2-like transcription factor by assembling a cullin 4-based ubiquitin ligase in tomato

USDA-ARS?s Scientific Manuscript database

Fleshy fruit undergo a novel developmental program that ends in the irreversible process of ripening and eventual tissue senescence. During these maturation processes, fruit undergo numerous physiological, biochemical and structural alterations, making them more attractive to seed dispersal organism...

The dissociation of liquid silica at high pressure and temperature

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hicks, D; Boehly, T; Eggert, J

2005-11-17

Liquid silica at high pressure and temperature is shown to undergo significant structural modifications and profound changes in its electronic properties. Temperature measurements on shock waves in silica at 70-1000 GPa indicate that the specific heat of liquid SiO{sub 2} rises well above the Dulong-Petit limit, exhibiting a broad peak with temperature that is attributable to the growing structural disorder caused by bond-breaking in the melt. The simultaneous sharp rise in optical reflectivity of liquid SiO{sub 2} indicates that dissociation causes the electrical and therefore thermal conductivities of silica to attain metallic-like values of 1-5 x 10{sup 5} S/m andmore » 24-600 W/m.K respectively.« less

An updated meta-analysis on the effectiveness of preoperative prophylactic antibiotics in patients undergoing breast surgical procedures.

PubMed

Sajid, Muhammad S; Hutson, Kristian; Akhter, Naved; Kalra, Lorain; Rapisarda, Ignacio F; Bonomi, Ricardo

2012-01-01

To systematically analyze published randomized trials on the effectiveness of preoperative prophylactic antibiotics in patients undergoing breast surgical procedures. Trials on the effectiveness of preoperative prophylactic antibiotics in patients undergoing breast surgery were selected and analyzed to generate summated data (expressed as risk ratio [RR]) by using RevMan 5.0. Nine randomized controlled trials encompassing 3720 patients undergoing breast surgery were retrieved from the electronic databases. The antibiotics group comprised a total of 1857 patients and non-antibiotics group, 1863 patients. There was no heterogeneity [χ(2) = 7.61, d.f. = 7, p < 0.37; I(2) = 8%] amongst trials. Therefore, in the fixed-effects model (RR, 0.64; 95% CI, 0.50-0.83; z = 3.48; p < 0.0005), the use of preoperative prophylactic antibiotics in patients undergoing breast surgical procedures was statistically significant in reducing the incidence of surgical site infection (SSI). Furthermore, in the fixed-effects model (RR, 1.30; 95% CI, 0.89-1.90; z = 1.37; p < 0.17), adverse reactions secondary to the use of prophylactic antibiotics was not statistically significant between the two groups. Preoperative prophylactic antibiotics significantly reduce the risk of SSI after breast surgical procedures. The risk of adverse reactions from prophylactic antibiotic administration is not significant in these patients. Therefore, preoperative prophylactic antibiotics in breast surgery patients may be routinely administered. Further research is required, however, on risk stratification for SSI, timing and duration of prophylaxis, and the need for prophylaxis in patients undergoing breast reconstruction versus no reconstruction. © 2012 Wiley Periodicals, Inc.

Calcium and zirconium as texture modifiers during rolling and annealing of magnesium–zinc alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bohlen, Jan, E-mail: jan.bohlen@hzg.de; Wendt, Joachim; Nienaber, Maria

2015-03-15

Rolling experiments were carried out on a ternary Mg–Zn–Ca alloy and its modification with zirconium. Short time annealing of as-rolled sheets is used to reveal the microstructure and texture development. The texture of the as-rolled sheets can be characterised by basal pole figures with split peak towards the rolling direction (RD) and a broad transverse angular spread of basal planes towards the transverse direction (TD). During annealing the RD split peaks as well as orientations in the sheet plane vanish whereas the distribution of orientations tilted towards the TD remains. It is shown in EBSD measurements that during rolling bandsmore » of twin containing structures form. During subsequent annealing basal orientations close to the sheet plane vanish based on a grain nucleation and growth mechanism of recrystallisation. Orientations with tilt towards the TD remain in grains that do not undergo such a mechanism. The addition of Zr delays texture weakening. - Highlights: • Ca in Mg–Zn-alloys contributes to a significant texture weakening during rolling and annealing. • Grain nucleation and growth in structures consisting of twins explain a texture randomisation during annealing. • Grains with transverse tilt of basal planes preferentially do not undergo a grain nucleation and growth mechanism. • Zr delays the microstructure and texture development.« less

Thermodynamic and electrical properties of laser-shocked liquid deuterium

NASA Astrophysics Data System (ADS)

He, Zhiyu; Jia, Guo; Zhang, Fan; Luo, Kui; Huang, Xiuguang; Shu, Hua; Fang, Zhiheng; Ye, Junjian; Xie, Zhiyong; Xia, Miao; Fu, Sizu

2018-01-01

Liquid deuterium at high pressure and temperature has been observed to undergo significant electronic structural changes. Reflectivity and temperature measurements of liquid deuterium up to around 70 GPa were obtained using a quartz standard. The observed specific heat of liquid deuterium approaches the Dulong-Petit limit above 1 eV. Discussions on specific heat indicate a molecular dissociation below 1 eV and fully dissociated above 1.5 eV. Also, the electrical conductivity of deuterium estimated from reflectivity reaches 1.3 × 105 (Ωṡm)-1, proving that deuterium in this condition is a conducting degenerate liquid metal and undergo an insulator-metal transition. The results from specific heat, carrier density and conductivity agreed well with each other, which might be a reinforcement of the insulator-metal transition and the molecular dissociation. In addition, a new correction method of reflectivity in temperature calculation was proposed to improve the accuracy of temperature results. A new "dynamic calibration" was introduced in this work to make the experiments simpler and more accurate.

Ultimate biodegradability and ecotoxicity of orally administered antidiabetic drugs.

PubMed

Markiewicz, Marta; Jungnickel, Christian; Stolte, Stefan; Białk-Bielińska, Anna; Kumirska, Jolanta; Mrozik, Wojciech

2017-07-05

Hypoglycaemic pharmaceuticals are recently more and more frequently detected in the environment. In our previous study, we have shown that even though many of them undergo significant primary degradation some are transformed to stable products or undergo such transformation that a large part of the structure is still preserved. One of the main routes of elimination from wastewaters or surface waters is biodegradation and a lack thereof leads to accumulation in the environment. Within this work we tested the ultimate biodegradability of six oral antidiabetics: metformin and its main metabolite guanylurea, acarbose, glibenclamide, gliclazide, glimepiride and repaglinide. We also compared the experimental results obtained in this and accompanying work with models designed to predict biodegradability and showed that these models are only moderately successful. Additionally, we examined these compounds in acute Daphnia magna test to check if they might pose an ecotoxicological threat. Combining the results of biodegradability and toxicity tests allows a preliminary assessment of their potential environmental impact. Copyright © 2017 Elsevier B.V. All rights reserved.

Electrochemistry-assisted top-down characterization of disulfide-containing proteins.

PubMed

Zhang, Yun; Cui, Weidong; Zhang, Hao; Dewald, Howard D; Chen, Hao

2012-04-17

Covalent disulfide bond linkage in a protein represents an important challenge for mass spectrometry (MS)-based top-down protein structure analysis as it reduces the backbone cleavage efficiency for MS/MS dissociation. This study presents a strategy for solving this critical issue via integrating electrochemistry (EC) online with a top-down MS approach. In this approach, proteins undergo electrolytic reduction in an electrochemical cell to break disulfide bonds and then undergo online ionization into gaseous ions for analysis by electron-capture dissociation (ECD) and collision-induced dissociation (CID). The electrochemical reduction of proteins allows one to remove disulfide bond constraints and also leads to increased charge numbers of the resulting protein ions. As a result, sequence coverage was significantly enhanced, as exemplified by β-lactoglobulin A (24 vs 75 backbone cleavages before and after electrolytic reduction, respectively) and lysozyme (5 vs 66 backbone cleavages before and after electrolytic reduction, respectively). This methodology is fast and does not need chemical reductants, which would have an important impact in high-throughput proteomics research.

Tradeoff between noise reduction and inartificial visualization in a model-based iterative reconstruction algorithm on coronary computed tomography angiography.

PubMed

Hirata, Kenichiro; Utsunomiya, Daisuke; Kidoh, Masafumi; Funama, Yoshinori; Oda, Seitaro; Yuki, Hideaki; Nagayama, Yasunori; Iyama, Yuji; Nakaura, Takeshi; Sakabe, Daisuke; Tsujita, Kenichi; Yamashita, Yasuyuki

2018-05-01

We aimed to evaluate the image quality performance of coronary CT angiography (CTA) under the different settings of forward-projected model-based iterative reconstruction solutions (FIRST).Thirty patients undergoing coronary CTA were included. Each image was reconstructed using filtered back projection (FBP), adaptive iterative dose reduction 3D (AIDR-3D), and 2 model-based iterative reconstructions including FIRST-body and FIRST-cardiac sharp (CS). CT number and noise were measured in the coronary vessels and plaque. Subjective image-quality scores were obtained for noise and structure visibility.In the objective image analysis, FIRST-body produced the significantly highest contrast-to-noise ratio. Regarding subjective image quality, FIRST-CS had the highest score for structure visibility, although the image noise score was inferior to that of FIRST-body.In conclusion, FIRST provides significant improvements in objective and subjective image quality compared with FBP and AIDR-3D. FIRST-body effectively reduces image noise, but the structure visibility with FIRST-CS was superior to FIRST-body.

Attitudes of Patients With Cancer About Personalized Medicine and Somatic Genetic Testing

PubMed Central

Gray, Stacy W.; Hicks-Courant, Katherine; Lathan, Christopher S.; Garraway, Levi; Park, Elyse R.; Weeks, Jane C.

2012-01-01

Purpose: Dramatic advances in genomic technology stand to revolutionize cancer care; however, little is known about patients' understanding and acceptance of personalized medicine and widespread genetic testing (GT). Patients and Methods: We conducted a formative, semi-structured interview study with a random sample of patients with lung, colorectal, and breast cancers to assess awareness of personalized medicine and GT and attitudes about somatic GT. Willingness to undergo GT was elicited through hypothetic scenarios. Results: Sixty-nine patients participated; 71% were women; 42% were black; median age was 59 years; and 42% had an education level ≥ college. We found that a majority of patients either were not aware of the term “personalized medicine” or defined it in unexpected ways. Although many patients identified relevant benefits of somatic testing (eg, informs treatment), many patients also expressed significant concerns (ie, psychological harm and discrimination). A majority of patients expressed a willingness to undergo somatic (predictive, 96%, prognostic, 93%) and germline (cancer risk without incidental information, 87%; cancer risk with incidental information, 81%; pharmacogenetic, 91%) testing; however, far fewer patients expressed a willingness to undergo full genome sequencing (62%). Reluctance was attributed to concerns over incidental findings, information overload, and the lack of a clear benefit. Conclusion: Many patients relayed misunderstandings about somatic testing and a reluctance to undergo full sequencing; oncologists must carefully consider how they present testing to patients so that concerns over discrimination and psychological harm do not hinder test uptake. More work is needed to identify effective ways to communicate complex genomic concepts to patients and research participants. PMID:23598841

Factors predictive of critical value of hypocalcemia after total parathyroidectomy without autotransplantation in patients with secondary hyperparathyroidism.

PubMed

Yang, Meng; Zhang, Ling; Huang, Linping; Sun, Xiaoliang; Ji, Haoyang; Lu, Yao

2016-09-01

Severe hypocalcemia is the most dangerous complication occurring after total parathyroidectomy without autotransplantation (TPTX) for secondary hyperparathyroidism (SHPT). We aim to identify the prevalence and potential risk factors of very severe hypocalcemia in patients with SHPT undergoing TPTX. From April 2012 to August 2015, 157 patients with SHPT undergoing TPTX were reviewed. The critical value of hypocalcemia (CVH) was postoperative serum Ca(2+) levels of ≤1.5 mmol/L. Univariate analysis showed that patients in the CVH group were significantly younger than those in the non-CVH group. Sex ratio was significantly different between the two groups. The CVH group had significantly higher levels of preoperative PTH and ALP. Male sex and preoperative levels of PTH and ALP were significant independent risk factors by logistic regression analysis. Male sex, preoperative PTH and ALP were significantly associated with CVH in patients with SHPT undergoing TPTX.

Measuring the dynamic structure factor of a quantum gas undergoing a structural phase transition

PubMed Central

Landig, Renate; Brennecke, Ferdinand; Mottl, Rafael; Donner, Tobias; Esslinger, Tilman

2015-01-01

The dynamic structure factor is a central quantity describing the physics of quantum many-body systems, capturing structure and collective excitations of a material. In condensed matter, it can be measured via inelastic neutron scattering, which is an energy-resolving probe for the density fluctuations. In ultracold atoms, a similar approach could so far not be applied because of the diluteness of the system. Here we report on a direct, real-time and nondestructive measurement of the dynamic structure factor of a quantum gas exhibiting cavity-mediated long-range interactions. The technique relies on inelastic scattering of photons, stimulated by the enhanced vacuum field inside a high finesse optical cavity. We extract the density fluctuations, their energy and lifetime while the system undergoes a structural phase transition. We observe an occupation of the relevant quasi-particle mode on the level of a few excitations, and provide a theoretical description of this dissipative quantum many-body system. PMID:25944151

From SHAPE Signatures to 3-D Structures | Center for Cancer Research

Cancer.gov

RNAs undergo extensive folding to form sophisticated based-paired secondary structures that are, in part, indicators of more complex three-dimensional structures.  These 3-D shapes are an integral part of the cellular gene-expression machinery. Deconstructing these structures is no small matter, yet it is critical to understanding their function.

Reusable fast opening switch

DOEpatents

Van Devender, J.P.; Emin, D.

1983-12-21

A reusable fast opening switch for transferring energy, in the form of a high power pulse, from an electromagnetic storage device such as an inductor into a load. The switch is efficient, compact, fast and reusable. The switch comprises a ferromagnetic semiconductor which undergoes a fast transition between conductive and metallic states at a critical temperature and which undergoes the transition without a phase change in its crystal structure. A semiconductor such as europium rich europhous oxide, which undergoes a conductor to insulator transition when it is joule heated from its conductor state, can be used to form the switch.

Reusable fast opening switch

DOEpatents

Van Devender, John P.; Emin, David

1986-01-01

A reusable fast opening switch for transferring energy, in the form of a high power pulse, from an electromagnetic storage device such as an inductor into a load. The switch is efficient, compact, fast and reusable. The switch comprises a ferromagnetic semiconductor which undergoes a fast transition between conductive and insulating states at a critical temperature and which undergoes the transition without a phase change in its crystal structure. A semiconductor such as europium rich europhous oxide, which undergoes a conductor to insulator transition when it is joule heated from its conductor state, can be used to form the switch.

A registry-based randomized trial comparing radial and femoral approaches in women undergoing percutaneous coronary intervention: the SAFE-PCI for Women (Study of Access Site for Enhancement of PCI for Women) trial.

PubMed

Rao, Sunil V; Hess, Connie N; Barham, Britt; Aberle, Laura H; Anstrom, Kevin J; Patel, Tejan B; Jorgensen, Jesse P; Mazzaferri, Ernest L; Jolly, Sanjit S; Jacobs, Alice; Newby, L Kristin; Gibson, C Michael; Kong, David F; Mehran, Roxana; Waksman, Ron; Gilchrist, Ian C; McCourt, Brian J; Messenger, John C; Peterson, Eric D; Harrington, Robert A; Krucoff, Mitchell W

2014-08-01

This study sought to determine the effect of radial access on outcomes in women undergoing percutaneous coronary intervention (PCI) using a registry-based randomized trial. Women are at increased risk of bleeding and vascular complications after PCI. The role of radial access in women is unclear. Women undergoing cardiac catheterization or PCI were randomized to radial or femoral arterial access. Data from the CathPCI Registry and trial-specific data were merged into a final study database. The primary efficacy endpoint was Bleeding Academic Research Consortium type 2, 3, or 5 bleeding or vascular complications requiring intervention. The primary feasibility endpoint was access site crossover. The primary analysis cohort was the subgroup undergoing PCI; sensitivity analyses were conducted in the total randomized population. The trial was stopped early for a lower than expected event rate. A total of 1,787 women (691 undergoing PCI) were randomized at 60 sites. There was no significant difference in the primary efficacy endpoint between radial or femoral access among women undergoing PCI (radial 1.2% vs. 2.9% femoral, odds ratio [OR]: 0.39; 95% confidence interval [CI]: 0.12 to 1.27); among women undergoing cardiac catheterization or PCI, radial access significantly reduced bleeding and vascular complications (0.6% vs. 1.7%; OR: 0.32; 95% CI: 0.12 to 0.90). Access site crossover was significantly higher among women assigned to radial access (PCI cohort: 6.1% vs. 1.7%; OR: 3.65; 95% CI: 1.45 to 9.17); total randomized cohort: (6.7% vs. 1.9%; OR: 3.70; 95% CI: 2.14 to 6.40). More women preferred radial access. In this pragmatic trial, which was terminated early, the radial approach did not significantly reduce bleeding or vascular complications in women undergoing PCI. Access site crossover occurred more often in women assigned to radial access. (SAFE-PCI for Women; NCT01406236). Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Does use of intraoperative cell-salvage delay recovery in patients undergoing elective abdominal aortic surgery?

PubMed

Tavare, Aniket N; Parvizi, Nassim

2011-06-01

A best evidence topic in vascular surgery was written according to a structured protocol. The question addressed was whether the use of intraoperative cell-salvage (ICS) leads to negative outcomes in patients undergoing elective abdominal aortic surgery? Altogether 305 papers were found using the reported search, of which 10 were judged to represent the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers were tabulated. None of the 10 papers included in the analysis demonstrated that ICS use led to significantly higher incidence of cardiac or septic postoperative complications. Similarly, length of intensive treatment unit (ITU) or hospital stay and mortality in elective abdominal aortic surgery were not adversely affected. Indeed two trials actually show a significantly shorter hospital stay after ICS use, one a shorter ITU stay and another suggests lower rates of chest sepsis. Based on these papers, we concluded that the use of ICS does not cause increased morbidity or mortality when compared to standard practise of transfusion of allogenic blood, and may actually improve some clinical outcomes. As abdominal aortic surgery inevitably causes significant intraoperative blood loss, in the range of 661-3755 ml as described in the papers detailed in this review, ICS is a useful and safe strategy to minimise use of allogenic blood.

The effects of aromatherapy on pruritus in patients undergoing hemodialysis.

PubMed

Ro, You-Ja; Ha, Hyae-Chung; Kim, Chun-Gill; Yeom, Hye-A

2002-08-01

This study was designed to investigate the effects of aromatherapy on pruritus in patients with chronic renal failure undergoing hemodialysis. The participants were 29 adult patients living in Seoul, Korea. Thirteen patients were assigned to the experimental group and received the aromatherapy massage on the arm 3 times a week for 4 weeks. Pruritus score, skin pH, stratum corneum hydration, and pruritus-related biochemical markers were measured before and after the treatment. The results showed that pruritus score was significantly decreased after aromatherapy. Skin pH showed no significant changes in either group while stratum corneum hydration increased significantly in the experimental group after aromatherapy. The results support the use aromatherapy as a useful and effective method of managing pruritus in patients undergoing hemodialysis.

Simulating the formation of cosmic structure.

PubMed

Frenk, C S

2002-06-15

A timely combination of new theoretical ideas and observational discoveries has brought about significant advances in our understanding of cosmic evolution. Computer simulations have played a key role in these developments by providing the means to interpret astronomical data in the context of physical and cosmological theory. In the current paradigm, our Universe has a flat geometry, is undergoing accelerated expansion and is gravitationally dominated by elementary particles that make up cold dark matter. Within this framework, it is possible to simulate in a computer the emergence of galaxies and other structures from small quantum fluctuations imprinted during an epoch of inflationary expansion shortly after the Big Bang. The simulations must take into account the evolution of the dark matter as well as the gaseous processes involved in the formation of stars and other visible components. Although many unresolved questions remain, a coherent picture for the formation of cosmic structure is now beginning to emerge.

Limits on the Emission of Gamma Rays from M31 (The Andromeda Galaxy) with HAWC

NASA Astrophysics Data System (ADS)

Rubenzahl, Ryan; BenZvi, Segev; Wood, Joshua; HAWC Collaboration

2018-01-01

The detection of the Fermi Bubbles suggests that spiral galaxies such as the Milky Way can undergo active periods. Using gamma-ray observations, we can investigate the possibility that such structures are present in other nearby galaxies. We have analyzed the region around the Andromeda Galaxy (Messier Catalog M31) for signs of bubble-like emission using TeV gamma-ray data recorded by the High-Altitude Water Cherenkov Observatory. We fit a model consisting of two 6 kpc bubbles symmetric about and perpendicular to the M31 galactic plane and assume a power-law distribution for the gamma-ray flux. We compare the emission from these bubble regions to that expected from structures similar to the Fermi Bubbles found in the Milky Way. No significant emission was observed. We report upper limits on the TeV flux from Fermi Bubble structures in M31.

Evaluation of Spin Hamiltonian Parameters and Local Structure of Cu2+-doped Ion in xK2SO4-(50 - x)Na2SO4-50ZnSO4 Glasses with Various K2SO4 Concentrations

NASA Astrophysics Data System (ADS)

Ding, Ch.-Ch.; Wu, Sh.-Y.; Xu, Y.-Q.; Zhang, L.-J.; He, J.-J.

2018-03-01

The spin Hamiltonian parameters (SHPs), i.e., g factors and hyperfine structure constants, and local structures are theoretically studied by analyzing tetragonally elongated 3d9 clusters for Cu2+ in xK2SO4-(50 - x)Na2SO4-50ZnSO4 glasses with various K2SO4 concentrations x. The concentration dependences of the SHPs are attributed to the parabolic decreases of the cubic field parameter Dq, orbital reduction factor k, relative tetragonal elongation ratio τ, and core polarization constant κ with x. The [CuO6]10- clusters are found to undergo significant elongations of about 17% due to the Jahn-Teller effect. The calculated cubic field splittings and the SHPs at various concentrations agree well with the experimental data.

The Changing Family Structure.

ERIC Educational Resources Information Center

Bernard van Leer Foundation Newsletter, 1993

1993-01-01

This newsletter issue contains feature articles and short reports on how and why family structures are undergoing substantial change in many parts of the world. These articles include: (1) "The Changing Family Structure," a review of how families are changing and why; (2) "Peru: Families in the Andes"; (3) "Thailand:…

Pressure tuning the lattice and optical response of silver sulfide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Zhao, E-mail: zhaozhao@stanford.edu; Wei, Hua; Mao, Wendy L.

2016-06-27

Binary transition metal chalcogenides have attracted increasing attention for their unique structural and electronic properties. High pressure is a powerful tool for tuning the lattice and electronic structure of transition metal chalcogenides away from their pristine states. In this work, we systematically studied the in situ structural and optical behavior of silver sulfide (Ag{sub 2}S) under pressure by synchrotron X-ray diffraction and infrared spectroscopy measurements in a diamond anvil cell. Upon compression, Ag{sub 2}S undergoes structural symmetrization accompanied by a series of structural transitions while the crystallographic inequivalence of the two Ag sites is maintained. Electronically, pressure effectively tunes themore » ambient semiconducting Ag{sub 2}S into a metal at ∼22 GPa. Drude model analysis shows that the optical conductivity evolves significantly, reaching the highest value of 100 Ω{sup −1} cm{sup −1} at ∼40 GPa. Our results highlight the structural and electronic tunability of silver chalcogenides as a function of pressure and suggest the potential of Ag{sub 2}S as a platform for developing optical and opto-electronic applications.« less

Response of rocky invertebrate diversity, structure and function to the vertical layering of vegetation

NASA Astrophysics Data System (ADS)

Bustamante, María; Tajadura, Javier; Gorostiaga, José María; Saiz-Salinas, José Ignacio

2014-06-01

Macroalgae comprise a prominent part of the rocky benthos where many invertebrates develop, and are believed to be undergoing severe declines worldwide. In order to investigate how the vegetation structure (crustose, basal and canopy layers) contributes to the diversity, structure and function of benthic invertebrates, a total of 31 subtidal transects were sampled along the northeast Atlantic coast of Spain. Significant positive relationships were found between the canopy layer and faunal abundance, taxonomic diversity and functional group diversity. Canopy forming algae were also related to epiphytic invertebrates, medium size forms, colonial strategy and suspensivores. By contrast, basal algae showed negative relationships with all variables tested except for detritivores. Multivariate multiple regression analyses (DISTLM) point to crustose as well as canopy layers as the best link between seaweeds and invertebrate assemblage structure. A close relationship was found between taxonomic and functional diversities. In general, low levels of taxonomic redundancy were detected for functional groups correlated with vegetation structure. A conceptual model based on the results is proposed, describing distinct stages of invertebrate assemblages in relation to the vertical structure of vegetation.

The impact of atosiban on pregnancy outcomes in women undergoing in vitro fertilization-embryo transfer: A meta-analysis

PubMed Central

Huang, Qian-Yi; Rong, Min-Hua; Lan, Ai-Hua; Lin, Xiao-Miao; Lin, Xing-Gu; He, Rong-Quan; Chen, Gang; Li, Mu-Jun

2017-01-01

Background Atosiban is administered to women undergoing in vitro fertilization-embryo transfer (IVF-ET) to improve pregnancy outcomes. However, the results of this treatment were controversial. We conducted this meta-analysis to investigate whether atosiban improves pregnancy outcomes in the women undergoing in vitro fertilization (IVF). Methods Databases of PubMed, EMBASE, Web of Science, China BioMedicine, and Google Scholar were systematically searched. Meta-analyses were performed to investigate whether atosiban improves pregnancy outcomes in the women undergoing IVF. Results Our results showed that atosiban was associated with higher implantation (OR = 1.63, 95% CI: 1.17–2.27; P = 0.004) and clinical pregnancy (OR = 1.84, 95% CI: 1.31–2.57; P < 0.001) rates. However, atosiban showed no significant association with the miscarriage, live birth, multiple pregnancy or ectopic pregnancy rates. When a further subgroup analysis was performed in the women undergoing repeated implantation failure (RIF), implantation (OR = 1.93, 95% CI: 1.45–2.57; P < 0.001), clinical pregnancy (OR = 2.48, 95% CI: 1.70–3.64; P <0.001) and the live birth (OR = 2.89, 95% CI: 1.78–4.67; P < 0.001) rates were significantly higher in the case group. Nevertheless, no significant difference was detected in the miscarriage and multiple pregnancy rates between the case and control groups. Conclusion Atosiban may be more appropriate for women undergoing RIF and play only a limited role in improving pregnancy outcomes in the general population of women undergoing IVF. These conclusions should be verified in large and well-designed studies. PMID:28422984

Impact of prior permanent pacemaker on long-term clinical outcomes of patients undergoing percutaneous coronary intervention.

PubMed

Li, Yan-Jie; Zhang, Wei-Wei; Yang, Xiao-Xiao; Li, Ning; Qiu, Xing-Biao; Qu, Xin-Kai; Fang, Wei-Yi; Yang, Yi-Qing; Li, Ruo-Gu

2017-04-01

The impact of permanent pacemaker (PPM) on long-term clinical outcomes of patients undergoing percutaneous coronary intervention (PCI) has not been studied. PPM may increase heart failure (HF) burden on patients undergoing PCI. We recruited consecutive patients undergoing PCI and carried out a nested case-control study. Patients with confirmed PPM undergoing first PCI were identified and matched by age and sex in 1:1 fashion to patients without PPM undergoing first PCI. Clinical data were collected and analyzed. The primary endpoint outcomes were all-cause mortality and hospitalization for HF. The final analysis included 156 patients. The mean follow-up period was 4.6 ± 2.9 years. The overall all-cause mortality was 21.15%, without significant difference between the 2 groups (21.79% vs 20.51%; P = 0.85). However, the rate of HF-related hospitalization was significantly higher in patients with PPM than in controls (26.92% vs 10.26%; P = 0.008). After adjustment for hypertension, type 2 diabetes mellitus, hyperlipidemia, chronic kidney disease, stroke, left ventricular ejection fraction, brain natriuretic peptide, and acute coronary syndrome (ACS), PCI patients with PPM were still associated with a greater hospitalization rate for HF (odds ratio: 4.31, 95% confidence interval: 0.94-19.80, P = 0.061). Further analysis in the ACS subgroup showed VVI-mode pacing enhanced the risk for HF-associated hospitalization (adjusted odds ratio: 8.27, 95% confidence interval: 1.37-49.75, P = 0.02). PPM has no effect on all-cause mortality in patients undergoing first PCI but significantly increases the HF-associated hospitalization rate, especially in ACS patients. © 2016 Wiley Periodicals, Inc.

A preliminary study of the relationship between the long arm of the Y chromosome (Yqh+) and reproductive outcomes in IVF/ICSI-ET.

PubMed

Xiao, Zhuoni; Zhou, Xin; Xu, Wangming; Yang, Jing

2012-11-01

To compare the reproductive outcomes of Yqh+-carrying and control couples undergoing IVF/ICSI treatments. Retrospective analysis of 72 Yqh+ carriers and 986 Yqh+ non-carriers undergoing their first cycle of ART in a single centre between August 2005 and May 2011. Yqh+ carrying couples had significantly worse reproductive outcomes compared with control couples undergoing IVF treatment. There were a significantly higher cancellation rate (20.69% vs 7.9%; P<0.05; OR, 3.03; CI, 1.18-7.79) and a significant lower fertilisation rate (50.05% vs 66.01%; P<0.05; OR, 0.61; CI, 0.49-0.57), implantation rate (8.33% vs 20.87%; P<0.05; OR, 0.35; CI, 0.14-0.87), good quality embryo ratio (44.70% vs 57.89%; P<0.05; OR, 0.59; CI, 0.43-0.80) and clinical pregnancy rate (17.39% vs 39.59%; P<0.05; OR, 0.32; CI, 0.11-0.96) in Yqh+ group compared with control group undergoing IVF treatment. Yqh+ carrying couples had similar reproductive outcomes compared with control couples undergoing ICSI treatment. The Y chromosome polymorphic variant Yqh+ most likely plays a role in infertility. Yqh+ couples with poor reproductive outcomes in IVF treatment can be advised to undergo ICSI to improve their reproductive results in the next cycle. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Morphological and chemical changes of aerosolized E. coli treated with a dielectric barrier discharge

DOE PAGES

Romero-Mangado, Jaione; Nordlund, Dennis; Soberon, Felipe; ...

2016-02-12

This paper presents the morphological and chemical modification of the cell structure of aerosolized Escherichia coli treated with a dielectric barrier discharge (DBD). Exposure to DBD results in severe oxidation of the bacteria, leading to the formation of hydroxyl groups and carbonyl groups and a significant reduction in amine functionalities and phosphate groups. Near edge x-ray absorption fine structure(NEXAFS) measurements confirm the presence of additional oxide bonds upon DBD treatment, suggesting oxidation of the outer layer of the cell wall. Electron microscopy images show that the bacteria undergo physical distortion to varying degrees, resulting in deformation of the bacterial structure.more » The electromagnetic field around the DBD coil causes severe damage to the cell structure, possibly resulting in leakage of vital cellular materials. The oxidation and chemical modification of the bacterial components are evident from the Fourier transform infrared spectroscopy and NEXAFS results. The bacterial reculture experiments confirm inactivation of airborne E. coli upon treating with DBD.« less

Antisite occupation induced single anionic redox chemistry and structural stabilization of layered sodium chromium sulfide

DOE PAGES

Shadike, Zulipiya; Zhou, Yong -Ning; Chen, Lan -Li; ...

2017-08-30

The intercalation compounds with various electrochemically active or inactive elements in the layered structure have been the subject of increasing interest due to their high capacities, good reversibility, simple structures and ease of synthesis. However, their reversible intercalation/deintercalation redox chemistries in all previous compounds involve a single cationic redox reaction or a cumulative cationic and anionic redox reaction. Here we report an anionic redox only chemistry and structural stabilization of layered sodium chromium sulfide. It is discovered that sulfur in sodium chromium sulfide is electrochemical active undergoing oxidation/reduction of sulfur rather than chromium. Significantly, sodium ions can successfully move outmore » and into without changing its lattice parameter c, which is explained in terms of the occurrence of chromium/sodium vacancy antisite during desodiation and sodiation processes. Here, our present work not only enriches the electrochemistry of layered intercalation compounds, but also extends the scope of investigation on high-capacity electrodes.« less

Native state volume fluctuations in proteins as a mechanism for dynamic allostery

DOE PAGES

Law, Anthony B.; Sapienza, Paul J.; Zhang, Jun; ...

2017-01-17

Allostery enables tight regulation of protein function in the cellular environment. While existing models of allostery are firmly rooted in the current structure-function paradigm, the mechanistic basis for allostery in the absence of structural change remains unclear. In this study, we show that a typical globular protein is able to undergo significant changes in volume under native conditions while exhibiting no additional changes in protein structure. These native state volume fluctuations were found to correlate with changes in internal motions that were previously recognized as a source of allosteric entropy. This finding offers a novel mechanistic basis for allostery inmore » the absence of canonical structural change. As a result, the unexpected observation that function can be derived from expanded, low density protein states has broad implications for our understanding of allostery and suggests that the general concept of the native state be expanded to allow for more variable physical dimensions with looser packing.« less

The Peierls stress of the moving [Formula: see text] screw dislocation in Ta.

PubMed

Liu, Ruiping; Wang, Shaofeng; Wu, Xiaozhi

2009-08-26

The Peierls stress of the moving [Formula: see text] screw dislocation with a planar and non-dissociated core structure in Ta has been calculated. The elastic strain energy which is associated with the discrete effect of the lattice and ignored in classical Peierls-Nabarro (P-N) theory has been taken into account in calculating the Peierls stress, and it can make the Peierls stress become smaller. The Peierls stress we obtain is very close to the experimental data. As shown in the numerical calculations and atomistic simulations, the core structure of the screw dislocation undergoes significant changes under the explicit stress before the screw dislocation moves. Moreover, the mechanism of the screw dislocation is revealed by our results and the experimental data that the screw dislocation retracts its extension in three {110} planes and transforms its dissociated core structure into a planar configuration. Therefore, the core structure of the moving [Formula: see text] screw dislocation in Ta is proposed to be planar.

Molecular and Supermolecular Structure of Commercial Pyrodextrins.

PubMed

Le Thanh-Blicharz, Joanna; Błaszczak, Wioletta; Szwengiel, Artur; Paukszta, Dominik; Lewandowicz, Grażyna

2016-09-01

Size exclusion chromatography with triple detection as well as infrared spectroscopy studies of commercially available pyrodextrins proved that these molecules are characterized not only by significantly lower molecular mass, in comparison to that of native starch, but also by increased branching. Therefore, pyrodextrins adopt a very compact structure in solution and show Newtonian behavior under shear in spite of their molecular masses of tens of thousands Daltons. The results also indicate that 50% reduction of digestibility of pyrodextrins is, to a minor extent, caused by formation of low-molecular color compounds containing carbonyl functional groups. The main reason is, as postulated in the literature, transglycosidation that leads to decreased occurrence of α-1,4-glycoside bonds in the molecular structure. In the process of dextrinization starch also undergoes changes in supermolecular structure, which, however, have no influence on digestibility. Likewise, the effect of formation of low-molecular colorful compounds containing carbonyl groups is not crucial. © 2016 Institute of Food Technologists®

Antisite occupation induced single anionic redox chemistry and structural stabilization of layered sodium chromium sulfide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shadike, Zulipiya; Zhou, Yong -Ning; Chen, Lan -Li

The intercalation compounds with various electrochemically active or inactive elements in the layered structure have been the subject of increasing interest due to their high capacities, good reversibility, simple structures and ease of synthesis. However, their reversible intercalation/deintercalation redox chemistries in all previous compounds involve a single cationic redox reaction or a cumulative cationic and anionic redox reaction. Here we report an anionic redox only chemistry and structural stabilization of layered sodium chromium sulfide. It is discovered that sulfur in sodium chromium sulfide is electrochemical active undergoing oxidation/reduction of sulfur rather than chromium. Significantly, sodium ions can successfully move outmore » and into without changing its lattice parameter c, which is explained in terms of the occurrence of chromium/sodium vacancy antisite during desodiation and sodiation processes. Here, our present work not only enriches the electrochemistry of layered intercalation compounds, but also extends the scope of investigation on high-capacity electrodes.« less

Structure of a Venezuelan equine encephalitis virus assembly intermediate isolated from infected cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lamb, Kristen; Lokesh, G.L.; Sherman, Michael

2010-10-25

Venezuelan equine encephalitis virus (VEEV) is a prototypical enveloped ssRNA virus of the family Togaviridae. To better understand alphavirus assembly, we analyzed newly formed nucleocapsid particles (termed pre-viral nucleocapsids) isolated from infected cells. These particles were intermediates along the virus assembly pathway, and ultimately bind membrane-associated viral glycoproteins to bud as mature infectious virus. Purified pre-viral nucleocapsids were spherical with a unimodal diameter distribution. The structure of one class of pre-viral nucleocapsids was determined with single particle reconstruction of cryo-electron microscopy images. These studies showed that pre-viral nucleocapsids assembled into an icosahedral structure with a capsid stoichiometry similar to themore » mature nucleocapsid. However, the individual capsomers were organized significantly differently within the pre-viral and mature nucleocapsids. The pre-viral nucleocapsid structure implies that nucleocapsids are highly plastic and undergo glycoprotein and/or lipid-driven rearrangements during virus self-assembly. This mechanism of self-assembly may be general for other enveloped viruses.« less

Effect of dissolved LiCl on the ionic liquid-Au(111) interface: an in situ STM study

NASA Astrophysics Data System (ADS)

Borisenko, Natalia; Atkin, Rob; Lahiri, Abhishek; Zein El Abedin, Sherif; Endres, Frank

2014-07-01

The structure of the electrolyte/electrode interface plays a significant role in electrochemical processes. To date, most studies are focusing on understanding the interfacial structure in pure ionic liquids. In this paper in situ scanning tunnelling microscopy (STM) has been employed to elucidate the structure of the charged Au(111)-ionic liquid (1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate, [Py1,4]FAP) interface in the presence of 0.1 M LiCl. The addition of the Li salt to the ionic liquid has a strong influence on the interfacial structure. In the first STM scan in situ measurements reveal that Au(111) undergoes the (22 \\times \\surd 3) ‘herringbone’ reconstruction in a certain potential regime, and there is strong evidence that the gold surface dissolves at negative electrode potentials in [Py1,4]FAP containing LiCl. Bulk deposition of Li is obtained at -2.9 V in the second STM scan.

Protein Interaction Profile Sequencing (PIP-seq).

PubMed

Foley, Shawn W; Gregory, Brian D

2016-10-10

Every eukaryotic RNA transcript undergoes extensive post-transcriptional processing from the moment of transcription up through degradation. This regulation is performed by a distinct cohort of RNA-binding proteins which recognize their target transcript by both its primary sequence and secondary structure. Here, we describe protein interaction profile sequencing (PIP-seq), a technique that uses ribonuclease-based footprinting followed by high-throughput sequencing to globally assess both protein-bound RNA sequences and RNA secondary structure. PIP-seq utilizes single- and double-stranded RNA-specific nucleases in the absence of proteins to infer RNA secondary structure. These libraries are also compared to samples that undergo nuclease digestion in the presence of proteins in order to find enriched protein-bound sequences. Combined, these four libraries provide a comprehensive, transcriptome-wide view of RNA secondary structure and RNA protein interaction sites from a single experimental technique. © 2016 by John Wiley & Sons, Inc. Copyright © 2016 John Wiley & Sons, Inc.

[Evaluation of psychological fear in children undergoing head-up tilt test].

PubMed

Chu, Wei-Hong; Wu, Li-Jia; Wang, Cheng; Lin, Ping; Li, Fang; Zhu, Li-Ping; Ran, Jing; Zou, Run-Mei; Liu, De-Yu

2014-03-01

To investigate the effects of different tilt angles of head-up tilt test (HUTT) and different responses to HUTT on the psychological fear in children undergoing the test. HUTT was performed on children with unexplained syncope or pre-syncope (107 cases: 52 males and 55 females), aged 5.5-17.8 years (mean 12.0±2.8 years). All subjects were randomly assigned to undergo HUTT at an angle of 60°, 70° or 80°; the negative cases underwent sublingual nitroglycerin-provocation HUTT at the same tilt angle. The Wong-Baker Faces Pain Rating Scale was used for self-assessment of psychological fear in subjects during HUTT at the end point of the test. The positive rate, hemodynamic changes and distribution of response types showed no significant differences between children at tilt angles of 60°, 70° and 80° (P>0.05). The greater the tilt angle, the higher the degree of psychological fear in children undergoing the test, but there were no significant differences between them (P>0.05). The degree of psychological fear in children who showed a positive response to HUTT (n=76) was significantly higher than that in children who showed a negative response (n=31) (P<0.01). HUTT can cause psychological fear in children undergoing the test, and the degree of psychological fear increases in children tested at tilt angles from 60° to 80°, but the differences have no statistical significance. A positive response to HUTT can significantly increase the psychological fear in children.

Design of Nanostructured Biological Materials Through Self-Assembly of Peptides and Proteins

DTIC Science & Technology

2002-01-01

of applications, including scaffolding for tissue repair in regenerative medicine, drug delivery and biological surface engineering. Tirrell and...colleagues [2] designed artificial proteins that undergo self-assembly to form hydrogels responsive to pH and other environmental changes. Ghadiri and...showed that other β-sheet peptide systems can also undergo self-assembly into regular nanofiber structures. Although they share no sequence

NASA Dryden's F-15B aircraft with the Gulfstream Quiet Spike sonic boom mitigator attached undergoes ground vibration testing in preparation for test flights

NASA Image and Video Library

2006-05-01

NASA Dryden's F-15B testbed aircraft with the Gulfstream Quiet Spike sonic boom mitigator attached undergoes ground vibration testing in preparation for test flights. The project seeks to verify the structural integrity of the multi-segmented, articulating spike attachment designed to reduce and control a sonic boom.

Photochemically Induced Transformations of Transition Complexes.

DTIC Science & Technology

1993-05-17

simple Iron dinuclear species, the DPPM and DPPE phosphine bridged compounds undergo photolysis in CHCI3 to yield products containing formyl substitued...possible reaction pathway for the synthesis of these two monomers as byproducts In the ruthenium phosphine dimer preparation Is suggested. Full structural...DPPM dimer is also described. In contrast to the behavior of the simple iron dinuclear species, the DPPM and DPPE phosphine bridged compounds undergo

Solvent-induced controllable synthesis, single-crystal to single-crystal transformation and encapsulation of Alq3 for modulated luminescence in (4,8)-connected metal-organic frameworks.

PubMed

Lan, Ya-Qian; Jiang, Hai-Long; Li, Shun-Li; Xu, Qiang

2012-07-16

In this work, for the first time, we have systematically demonstrated that solvent plays crucial roles in both controllable synthesis of metal-organic frameworks (MOFs) and their structural transformation process. With solvent as the only variable, five new MOFs with different structures have been constructed, in which one MOF undergoes solvent-induced single-crystal to single-crystal (SCSC) transformation that involves not only solvent exchange but also the cleavage and formation of coordination bonds. Particularly, a significant crystallographic change has been realized through an unprecedented three-step SCSC transformation process. Furthermore, we have demonstrated that the obtained MOF could be an excellent host for chromophores such as Alq3 for modulated luminescent properties.

On the Origin of Banded Structure in Dusty Protoplanetary Discs: HL Tau and TW Hya

NASA Astrophysics Data System (ADS)

Boley, Aaron C.

2017-10-01

We present simulations of planet-planetesimal interactions that can reproduce major and minor banded structure in the HL Tau and TW Hya discs provided that small grains trace the dynamically cold planetesimal population. The consequences of the model and its limitations will be discussed. In particular, the model requires that planetesimals form throughout the disc at early times, that planetesimal-planetesimal collisions are predominately among the cold population, and that pebble accretion leads to mass redistribution of the small grains onto planetesimals before the grains can undergo significant radial drift. The meteortic record may suggest that a similar process occurred in the Solar System. The model implies that grain size distributions inferred from submm/mm studies may reflect early debris processes rather than grain growth.

Confocal Raman imaging of optical waveguides in LiNbO3 fabricated by ultrafast high-repetition rate laser-writing.

PubMed

Ródenas, Airán; Nejadmalayeri, Amir H; Jaque, Daniel; Herman, Peter

2008-09-01

We report on the confocal Raman characterization of the micro-structural lattice changes induced during the high-repetition rate ultrafast laser writing of buried optical waveguides in lithium niobate (LiNbO(3)) crystals. While the laser beam focal volume is characterized by a significant lattice expansion together with a high defect concentration, the adjacent waveguide zone is largely free of defects, undergoing only slight rearrangement of the oxygen octahedron in the LiNbO(3) lattice. The close proximity of these two zones has been found responsible for the propagation losses of the guided light. Subjacent laser-induced periodic micro-structures have been also observed inside the laser focal volume, and identified with a strong periodic distribution of lattice defects.

Creating Reconfigurable Materials Using ``Colonies'' of Oscillating Polymer Gels

NASA Astrophysics Data System (ADS)

Deb, Debabrata; Dayal, Pratyush; Kuksenok, Olga; Balazs, Anna

2013-03-01

Species ranging from single-cell organisms to social insects can undergo auto-chemotaxis, where the entities move towards a chemo-attractant that they themselves emit. This mode of signaling allows the organisms to form large-scale structures. Using computational modeling, we show that millimeter-sized polymer gels can display similar auto-chemotaxis. In particular, we demonstrate that gels undergoing the self-oscillating Belousov-Zhabotinsky (BZ) reaction not only respond to a chemical signal from the surrounding solution, but also emit this signal and thus, multiple gel pieces can spontaneously self-aggregate. We focus on the collective behavior of ``colonies'' of BZ gels and show that communication between the individual pieces critically depends on all the neighboring gels. We isolate the conditions at which the BZ gels can undergo a type of self-recombining: if a larger gel is cut into distinct pieces that are moved relatively far apart, then their auto-chemotactic behavior drives them to move and autonomously recombine into a structure resembling the original, uncut sample. These findings reveal that the BZ gels can be used as autonomously moving building blocks to construct multiple structures and thus, provide a new route for creating dynamically reconfigurable materials.

Structural and functional brain changes in early- and mid-stage primary open-angle glaucoma using voxel-based morphometry and functional magnetic resonance imaging.

PubMed

Jiang, Ming-Ming; Zhou, Qing; Liu, Xiao-Yong; Shi, Chang-Zheng; Chen, Jian; Huang, Xiang-He

2017-03-01

To investigate structural and functional brain changes in patients with primary open-angle glaucoma (POAG) by using voxel-based morphometry based on diffeomorphic anatomical registration through exponentiated Lie algebra (VBM-DARTEL) and blood oxygenation level dependent functional magnetic resonance imaging (BOLD-fMRI), respectively.Thirteen patients diagnosed with POAG and 13 age- and sex-matched healthy controls were enrolled in the study. For each participant, high-resolution structural brain imaging and blood flow imaging were acquired on a 3.0-Tesla magnetic resonance imaging (MRI) scanner. Structural and functional changes between the POAG and control groups were analyzed. An analysis was carried out to identify correlations between structural and functional changes acquired in the previous analysis and the retinal nerve fiber layer (RNFL).Patients in the POAG group showed a significant (P < 0.001) volume increase in the midbrain, left brainstem, frontal gyrus, cerebellar vermis, left inferior parietal lobule, caudate nucleus, thalamus, precuneus, and Brodmann areas 7, 18, and 46. Moreover, significant (P < 0.001) BOLD signal changes were observed in the right supramarginal gyrus, frontal gyrus, superior frontal gyrus, left inferior parietal lobule, left cuneus, and left midcingulate area; many of these regions had high correlations with the RNFL.Patients with POAG undergo widespread and complex changes in cortical brain structure and blood flow. (ClinicalTrials.gov number: NCT02570867).

Structural alterations in tumor-draining lymph nodes before papillary thyroid carcinoma metastasis.

PubMed

Hinson, Andrew M; Massoll, Nicole A; Jolly, Lee Ann; Stack, Brendan C; Bodenner, Donald L; Franco, Aime T

2017-08-01

The purpose of this study was to define and characterize the thyroid tumor-draining lymph nodes in genetically engineered mice harboring thyroid-specific expression of oncogenic Braf V600E with and without Pten insufficiency. After intratumoral injection of methylene blue, the lymphatic drainage of the thyroid gland was visualized in real time. The thyroid gland/tumor was resected en bloc with the respiratory system for histological analysis. Although mice harboring Braf V600E mutations were smaller in body size compared with their wild-type (WT) littermates, the size of their thyroid glands and deep cervical lymph nodes were significantly larger. Additionally, the tumor-draining lymph nodes showed increased and enlarged lymphatic sinuses that were distributed throughout the cortex and medulla. Tumor-reactive lymphadenopathy and histiocytosis, but no frank metastases, were observed in all mice harboring Braf V600E mutations. The tumor-draining lymph nodes undergo significant structural alterations in immunocompetent mice, and this may represent a primer for papillary thyroid carcinoma (PTC) metastasis. © 2017 Wiley Periodicals, Inc.

Inhibition of development of peripheral neuropathy in streptozotocin-induced diabetic rats with N-acetylcysteine.

PubMed

Sagara, M; Satoh, J; Wada, R; Yagihashi, S; Takahashi, K; Fukuzawa, M; Muto, G; Muto, Y; Toyota, T

1996-03-01

N-acetylcysteine (NAC) is a precursor of glutathione (GSH) synthesis, a free radical scavenger and an inhibitor of tumour necrosis factor alpha (TNF). Because these functions might be beneficial in diabetic complications, in this study we examined whether NAC inhibits peripheral neuropathy. Motor nerve conduction velocity (MNCV) was significantly decreased in streptozotocin-induced-diabetic Wistar rats compared to control rats. Oral administration of NAC reduced the decline of MNCV in diabetic rats. Structural analysis of the sural nerve disclosed significant reduction of fibres undergoing myelin wrinkling and inhibition of myelinated fibre atrophy in NAC-treated diabetic rats. NAC treatment had no effect on blood glucose levels or on the nerve glucose, sorbitol and cAMP contents, whereas it corrected the decreased GSH levels in erythrocytes, the increased lipid peroxide levels in plasma and the increased lipopolysaccharide-induced TNF activity in sera of diabetic rats. Thus, NAC inhibited the development of functional and structural abnormalities of the peripheral nerve in streptozotocin-induced diabetic rats.

Activator Protein-1: redox switch controlling structure and DNA-binding

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yin, Zhou; Machius, Mischa; Nestler, Eric J.

The transcription factor, activator protein-1 (AP-1), binds to cognate DNA under redox control; yet, the underlying mechanism has remained enigmatic. A series of crystal structures of the AP-1 FosB/JunD bZIP domains reveal ordered DNA-binding regions in both FosB and JunD even in absence DNA. However, while JunD is competent to bind DNA, the FosB bZIP domain must undergo a large conformational rearrangement that is controlled by a ‘redox switch’ centered on an inter-molecular disulfide bond. Solution studies confirm that FosB/JunD cannot undergo structural transition and bind DNA when the redox-switch is in the ‘OFF’ state, and show that the mid-pointmore » redox potential of the redox switch affords it sensitivity to cellular redox homeostasis. The molecular and structural studies presented here thus reveal the mechanism underlying redox-regulation of AP-1 Fos/Jun transcription factors and provide structural insight for therapeutic interventions targeting AP-1 proteins.« less

[Influence of Uncertainty and Uncertainty Appraisal on Self-management in Hemodialysis Patients].

PubMed

Jang, Hyung Suk; Lee, Chang Suk; Yang, Young Hee

2015-04-01

This study was done to examine the relation of uncertainty, uncertainty appraisal, and self-management in patients undergoing hemodialysis, and to identify factors influencing self-management. A convenience sample of 92 patients receiving hemodialysis was selected. Data were collected using a structured questionnaire and medical records. The collected data were analyzed using descriptive statistics, t-test, ANOVA, Pearson correlations and multiple regression analysis with the SPSS/WIN 20.0 program. The participants showed a moderate level of uncertainty with the highest score being for ambiguity among the four uncertainty subdomains. Scores for uncertainty danger or opportunity appraisals were under the mid points. The participants were found to perform a high level of self-management such as diet control, management of arteriovenous fistula, exercise, medication, physical management, measurements of body weight and blood pressure, and social activity. The self-management of participants undergoing hemodialysis showed a significant relationship with uncertainty and uncertainty appraisal. The significant factors influencing self-management were uncertainty, uncertainty opportunity appraisal, hemodialysis duration, and having a spouse. These variables explained 32.8% of the variance in self-management. The results suggest that intervention programs to reduce the level of uncertainty and to increase the level of uncertainty opportunity appraisal among patients would improve the self-management of hemodialysis patients.

Topics and structure in preoperative nursing consultations with patients undergoing colorectal cancer surgery.

PubMed

Pettersson, Monica E; Öhlén, Joakim; Friberg, Febe; Hydén, Lars-Christer; Carlsson, Eva

2017-12-01

The preoperative education, which occurs in preoperative patient consultations, is an important part of the surgical nurse's profession. These consultations may be the building blocks of a partnership that facilitates communication between patient and nurse. The aim of the study was to describe topics and structure and documentation in preoperative nursing consultations with patients undergoing surgery for colorectal cancer. The study was based on analysis of consultations between seven patients and nurses at a Swedish university hospital. The preplanned preoperative consultations were audio-recorded and transcribed verbatim. The structure of the consultations was described in terms of phases and the text was analysed according to a manifest content analysis RESULTS: The consultations were structured on an agenda that was used variously and communicating different topics in an equally varied manner. Seven main topics were found: Health status, Preparation before surgery, Discovery, Tumour, Operation, Symptoms and Recovery after surgery. The topic structure disclosed a high number of subtopics. The main topics 'Discovery', 'Tumour' and 'Symptoms' were only raised by patients and occupied only 11% of the discursive space. Documentation was sparse and included mainly task-oriented procedures rather than patients' worries and concerns. There was no clear structure regarding preoperative consultation purpose and content. Using closed questions instead of open is a hindrance of developing a dialogue and thus patient participation. Preoperative consultation practice needs to be strengthened to include explicit communication of the consultations' purpose and agenda, with nurses actively discussing and responding to patients' concerns and sensitive issues. The results of the study facilitate the development of methods and structure to support person-centred communication where the patient is given space to get help with the difficult issues he/she may have when undergoing surgery. © 2016 Nordic College of Caring Science.

Regaining a sense of agency and shared self-reliance: the experience of advanced disease cancer patients participating in a multidimensional exercise intervention while undergoing chemotherapy--analysis of patient diaries.

PubMed

Midtgaard, Julie; Stelter, Reinhard; Rørth, Mikael; Adamsen, Lis

2007-04-01

Evidence is emerging that exercise can reduce psychological distress in cancer patients undergoing treatment. The present study aimed to (qualitatively) explore the experiences of advanced disease cancer patients participating in a 6-week, 9-hours weekly, structured, group-based multidimensional exercise intervention while undergoing chemotherapy. Unstructured diaries from a purposive sample of three females and two males (28-52 years old) who participated in the program served as the database. Data were analyzed using a phenomenological, narrative method. The analysis yielded three themes: shifting position, self-surveillance, and negotiated strength. The intervention highlighted situations making it possible for the participants to negate psychological and physical constraints. The concept of structured exercise contains viable psychotherapeutic potentials by allowing the development of alternative bodily and mental realities complying with cancer patients' demands and abilities to regain autonomy and commitment to discover and adopt a sense of agency and shared self-reliance.

Prevalence and predictors of renal artery stenosis in patients undergoing peripheral and coronary angiography.

PubMed

Shukla, Anand N; Madan, Tarun H; Jayaram, Ashwal A; Kute, Vivek B; Rawal, Jayesh R; Manjunath, A P; Udhreja, Satyam

2013-12-01

Renal artery stenosis is a potential cause of secondary hypertension, ischemic nephropathy and end-stage renal disease. Atherosclerosis is by far the most common etiology of renal artery stenosis in elderly. We investigated whether the presence of significant atherosclerotic renal artery stenosis (ARAS) with luminal diameter narrowing ≥50 % could be predicted in patients undergoing peripheral and coronary angiography. The records of 3,500 consecutive patients undergoing simultaneous renal angiography along with peripheral and coronary angiography were reviewed. The patients with known renal artery disease were excluded. Prevalence of ARAS was 5.7 %. Significant ARAS (luminal diameter narrowing ≥50 %) was present in 139 patients (3.9 %). Hypertension with altered serum creatinine and triple-vessel CAD were associated with significant renal artery stenosis in multivariate analysis. No significant relationship between the involved coronary arteries like left anterior descending, left circumflex, right coronary artery and ARAS was found. Only hypertension and altered serum creatinine were associated with bilateral ARAS. Extent of CAD or risk factors like diabetes, hyperlipidemia or smoking did not predict the unilateral or bilateral ARAS. Prevalence of ARAS among the patients in routine cardiac catheterization was 5.7 %. Hypertension is closely associated with significant ARAS. Significant CAD in the form of triple-vessel disease and altered renal function tests are closely associated with ARAS. They predict the presence of significant renal artery stenosis in patients undergoing routine peripheral and coronary angiography. Moreover, hypertension and altered renal functions predict bilateral ARAS.

Enhanced Recovery After Surgery Program Implementation in 2 Surgical Populations in an Integrated Health Care Delivery System.

PubMed

Liu, Vincent X; Rosas, Efren; Hwang, Judith; Cain, Eric; Foss-Durant, Anne; Clopp, Molly; Huang, Mengfei; Lee, Derrick C; Mustille, Alex; Kipnis, Patricia; Parodi, Stephen

2017-07-19

Novel approaches to perioperative surgical care focus on optimizing nutrition, mobility, and pain management to minimize adverse events after surgical procedures. To evaluate the outcomes of an enhanced recovery after surgery (ERAS) program among 2 target populations: patients undergoing elective colorectal resection and patients undergoing emergency hip fracture repair. A pre-post difference-in-differences study before and after ERAS implementation in the target populations compared with contemporaneous surgical comparator groups (patients undergoing elective gastrointestinal surgery and emergency orthopedic surgery). Implementation began in February and March 2014 and concluded by the end of 2014 at 20 medical centers within the Kaiser Permanente Northern California integrated health care delivery system. A multifaceted ERAS program designed with a particular focus on perioperative pain management, mobility, nutrition, and patient engagement. The primary outcome was hospital length of stay. Secondary outcomes included hospital mortality, home discharge, 30-day readmission rates, and complication rates. The study included a total of 3768 patients undergoing elective colorectal resection (mean [SD] age, 62.7 [14.1] years; 1812 [48.1%] male) and 5002 patients undergoing emergency hip fracture repair (mean [SD] age, 79.5 [11.8] years; 1586 [31.7%] male). Comparator surgical patients included 5556 patients undergoing elective gastrointestinal surgery and 1523 patients undergoing emergency orthopedic surgery. Most process metrics had significantly greater changes in the ERAS target populations after implementation compared with comparator surgical populations, including those for ambulation, nutrition, and opioid use. Hospital length of stay and postoperative complication rates were also significantly lower among ERAS target populations after implementation. The rate ratios for postoperative complications were 0.68 (95% CI, 0.46-0.99; P = .04) for patients undergoing colorectal resection and 0.67 (95% CI, 0.45-0.99, P = .05) for patients with hip fracture. Among patients undergoing colorectal resection, ERAS implementation was associated with decreased rates of hospital mortality (0.17; 95% CI, 0.03-0.86; P = .03), whereas among patients with hip fracture, implementation was associated with increased rates of home discharge (1.24; 95% CI, 1.06-1.44; P = .007). Multicenter implementation of an ERAS program among patients undergoing elective colorectal resection and patients undergoing emergency hip fracture repair successfully altered processes of care and was associated with significant absolute and relative decreases in hospital length of stay and postoperative complication rates. Rapid, large-scale implementation of a multidisciplinary ERAS program is feasible and effective in improving surgical outcomes.

Comparison of neurocognitive results after coronary artery bypass grafting and thoracic aortic surgery using retrograde cerebral perfusion.

PubMed

Miyairi, Takeshi; Takamoto, Shinichi; Kotsuka, Yutaka; Takeuchi, Atsuko; Yamanaka, Katsuo; Sato, Hajime

2005-07-01

Retrograde cerebral perfusion (RCP) is used as an adjunctive method to hypothermic circulatory arrest to enhance cerebral protection in patients undergoing thoracic aortic surgery. It remains unclear whether RCP provides improved neurological and neuropsychological outcome. Forty-six patients undergoing thoracic aortic surgery using RCP, and 28 undergoing coronary artery bypass grafting (CABG; n = 28) with CPB, were enrolled in the study. Patients receiving RCP were subdivided into two groups, those with less than 60 min of RCP (S-RCP; n = 27) and with 60 min or more (L-RCP; n = 19). The patients' neurocognitive state was assessed by the revised Wechsler Adult Intelligence Scale a few days before operation, at 2-3 weeks and 4-6 months after operation. There were no stroke, seizure, and hospital mortality in either group. Significant decline between baseline and early scores were seen in three subtests (digit span, arithmetic, and picture completion) for S-RCP and four (digit span, arithmetic, picture completion, and picture arrangement) for L-RCP. Significant decline between baseline and late scores were seen in one subtest (arithmetic) for S-RCP, four (digit span, arithmetic, picture completion, and picture arrangement) for L-RCP, and one (object assembly) for CABG. The mean change of scores for one late test (digit symbol) was significantly lower in S-RCP than in CABG. The mean change of scores for three early tests (digit span, vocabulary, and picture arrangement) and four late tests (information, digit span, picture completion, and picture arrangement) were significantly lower in L-RCP than in CABG. Stepwise logistic regression analysis disclosed that, after considering the other variables, significant difference in test score changes were observed between CABG and L-RCP for two early tests (picture completion and digit symbol) as well as for three late tests (digit span, similarities, and picture completion). None of test score changes showed significant difference between CABG and S-RCP. The neurocognitive outcome in patients undergoing RCP less than 60 min were comparable with patients undergoing CABG without circulatory arrest. Prolonged RCP of 60 min or more in patients undergoing surgery of the thoracic aorta was associated with postoperative neurocognitive impairment.

Probing the Structure of the Escherichia coli Periplasmic Proteins HdeA and YmgD by Molecular Dynamics Simulations.

PubMed

Socher, Eileen; Sticht, Heinrich

2016-11-23

HdeA and YmgD are structurally homologous proteins in the periplasm of Escherichia coli. HdeA has been shown to represent an acid-activated chaperone, whereas the function of YmgD has not yet been characterized. We performed pH-titrating molecular dynamics simulations (pHtMD) to investigate the structural changes of both proteins and to assess whether YmgD may also exhibit an unfolding behavior similar to that of HdeA. The unfolding pathway of HdeA includes partially unfolded dimer structures, which represent a prerequisite for subsequent dissociation. In contrast to the coupled unfolding and dissociation of HdeA, YmgD displays dissociation of the folded subunits, and the subunits do not undergo significant unfolding even at low pH values. The differences in subunit stability between HdeA and YmgD may be explained by the structural features of helix D, which represents the starting point of unfolding in HdeA. In summary, the present study suggests that YmgD either is not an acid-activated chaperone or, at least, does not require unfolding for activation.

Phosphorylation Interferes with Maturation of Amyloid-β Fibrillar Structure in the N Terminus.

PubMed

Rezaei-Ghaleh, Nasrollah; Kumar, Sathish; Walter, Jochen; Zweckstetter, Markus

2016-07-29

Neurodegeneration is characterized by the ubiquitous presence of modifications in protein deposits. Despite their potential significance in the initiation and progression of neurodegenerative diseases, the effects of posttranslational modifications on the molecular properties of protein aggregates are largely unknown. Here, we study the Alzheimer disease-related amyloid-β (Aβ) peptide and investigate how phosphorylation at serine 8 affects the structure of Aβ aggregates. Serine 8 is shown to be located in a region of high conformational flexibility in monomeric Aβ, which upon phosphorylation undergoes changes in local conformational dynamics. Using hydrogen-deuterium exchange NMR and fluorescence quenching techniques, we demonstrate that Aβ phosphorylation at serine 8 causes structural changes in the N-terminal region of Aβ aggregates in favor of less compact conformations. Structural changes induced by serine 8 phosphorylation can provide a mechanistic link between phosphorylation and other biological events that involve the N-terminal region of Aβ aggregates. Our data therefore support an important role of posttranslational modifications in the structural polymorphism of amyloid aggregates and their modulatory effect on neurodegeneration. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Outcomes of complete vs targeted approaches to endoscopic sinus surgery.

PubMed

DeConde, Adam S; Suh, Jeffrey D; Mace, Jess C; Alt, Jeremiah A; Smith, Timothy L

2015-08-01

Functional endoscopic sinus surgery (FESS) was historically predicated on targeted widening of narrow anatomic structures that caused postobstructive persistent sinus inflammation. It is now clear that chronic rhinosinusitis (CRS) is a multifactorial disease with subsets of patients which may require a more extensive surgical approach. This study compares quality-of-life (QOL) and disease severity outcomes after FESS based on the extent of surgical intervention. Participants with CRS were prospectively enrolled into an ongoing, multi-institutional, observational, cohort study. Surgical extent was determined by physician discretion. Participants undergoing bilateral frontal sinusotomy, ethmoidectomy, maxillary antrostomy, and sphenoidotomy were considered to have undergone "complete" surgery, whereas all other participants were categorized as receiving "targeted" surgery. Improvement was evaluated between surgical subgroups with at least 6-month follow-up using the 22-item Sino-Nasal Outcome Test (SNOT-22) and the Brief Smell Inventory Test (B-SIT). A total of 311 participants met inclusion criteria with 147 subjects undergoing complete surgery and 164 targeted surgery. A higher prevalence of asthma, acetylsalicylic acid (ASA) sensitivity, nasal polyposis, and a history of prior sinus surgery (p ≤ 0.002) was present in participants undergoing complete surgery. Mean improvement in SNOT-22 (28.1 ± 21.9 vs 21.9 ± 20.6; p = 0.011) and B-SIT (0.8 ± 3.1 vs 0.2 ± 2.4; p = 0.005) was greater in subjects undergoing complete surgery. Regression models demonstrated a 5.9 ± 2.5 greater relative mean improvement on SNOT-22 total scores with complete surgery over targeted approaches (p = 0.016). Complete surgery was an independent predictor of greater postoperative SNOT-22 score improvement, yet did not achieve clinical significance. Further study is needed to determine the optimal surgical extent. © 2015 ARS-AAOA, LLC.

Racing performance of Standardbred trotting horses undergoing surgery of the carpal flexor sheath and age- and sex-matched control horses.

PubMed

Carmalt, James L; Johansson, Bengt C; Zetterström, Sandra M; McOnie, Rebecca C

2017-07-01

OBJECTIVE To determine factors affecting race speed in Swedish Standardbred horses undergoing surgery of the carpal flexor sheath (CFS), to investigate whether preoperative racing speed was associated with specific intraoperative findings and whether horses returned to racing, and to compare the performance of horses undergoing surgery of the CFS with that of age- and sex-matched control horses. ANIMALS 149 Swedish Standardbred trotters undergoing surgery of the CFS and 274 age- and sex-matched control horses. PROCEDURES Medical records of CFS horses were examined. Racing data for CFS and control horses were retrieved from official online records. Generalizing estimating equations were used to examine overall and presurgery racing speeds and the association of preoperative clinical and intraoperative findings with preoperative and postoperative speeds. Multivariable regression analysis was used to examine career earnings and number of career races. Kaplan-Meier survival analysis was used to compare career longevity between CFS and control horses. RESULTS CFS horses were significantly faster than control horses. The CFS horses that raced before surgery were slower as they approached the surgery date, but race speed increased after surgery. There were 124 of 137 (90.5%) CFS horses that raced after surgery. No intrathecal pathological findings were significantly associated with preoperative racing speed. Career longevity did not differ between CFS and control horses. CONCLUSIONS AND CLINICAL RELEVANCE Horses undergoing surgery of the CFS had a good prognosis to return to racing after surgery. Racing careers of horses undergoing surgery of the CFS were not significantly different from racing careers of control horses.

46 CFR 71.50-3 - Drydock examination, internal structural examination, underwater survey, and alternate hull exam...

Code of Federal Regulations, 2010 CFR

2010-10-01

..., underwater survey, and alternate hull exam intervals. 71.50-3 Section 71.50-3 Shipping COAST GUARD...-3 Drydock examination, internal structural examination, underwater survey, and alternate hull exam... wooden hulls must undergo two drydock and two internal structural examinations within any five year...

Ba9V3Se15: a novel compound with spin chains

NASA Astrophysics Data System (ADS)

Zhang, Jun; Liu, Min; Wang, Xiancheng; Zhao, Kan; Duan, Lei; Li, Wenmin; Zhao, Jianfa; Cao, Lipeng; Dai, Guangyang; Deng, Zheng; Feng, Shaomin; Zhang, Sijia; Liu, Qingqing; Yang, Yi-feng; Jin, Changqing

2018-05-01

In this work, a novel compound Ba9V3Se15 with one-dimensional (1D) spin chains was synthesized under high-pressure and high-temperature conditions. It was systematically characterized via structural, magnetic, thermodynamic and transport measurements. Ba9V3Se15 crystallizes into a hexagonal structure with a space group of P-6c2 (188) and the lattice constants of a  =  b  =  9.5745(7) Å and c  =  18.7814(4) Å. The crystal structure consists of face-sharing octahedral VSe6 chains along c axis, which are trimeric and arranged in a triangular lattice in ab-plane. Ba9V3Se15 is a semiconductor and undergoes complex magnetic transitions. In the zero-field-cooled (ZFC) process with magnetic field of 10 Oe, Ba9V3Se15 sequentially undergoes ferrimagnetic and spin cluster glass transition at 2.5 K and 3.3 K, respectively. When the magnetic field exceeds 50 Oe, only the ferrimagnetic transition can be observed. Above the transition temperature, the specific heat contains a significant magnetic contribution that is proportional to T 1/2. The calculation suggests that the nearest neighbor (NN) intra-chain antiferromagnetic exchange J 1 is much larger than the next nearest neighbor (NNN) intra-chain ferromagnetic exchange J 2. Therefore, Ba9V3Se15 can be regarded as an effective ferromagnetic chains with effective spin-1/2 by the formation of the V(2)(↓) V(1)(↑) V(2)(↓) cluster.

Structural and Functional Role of Acetyltransferase hMOF K274 Autoacetylation

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCullough, Cheryl E.; Song, Shufei; Shin, Michael H.

Many histone acetyltransferases undergo autoacetylation, either through chemical or enzymatic means, to potentiate enzymatic cognate substrate lysine acetylation, although the mode and molecular role of such autoacetylation is poorly understood. The MYST family of histone acetyltransferases is autoacetylated at an active site lysine residue to facilitate cognate substrate lysine binding and acetylation. Here, we report on a detailed molecular investigation of Lys-274 autoacetylation of the human MYST protein Males Absent on the First (hMOF). A mutational scan of hMOF Lys-274 reveals that all amino acid substitutions of this residue are able to bind cofactor but are significantly destabilized, both inmore » vitro and in cells, and are catalytically inactive for cognate histone H4 peptide lysine acetylation. The x-ray crystal structure of a hMOF K274P mutant suggests that the reduced stability and catalytic activity stems from a disordering of the residue 274-harboring a α2-β7 loop. We also provide structural evidence that a C316S/E350Q mutant, which is defective for cognate substrate lysine acetylation; and biochemical evidence that a K268M mutant, which is defective for Lys-274 chemical acetylation in the context of a K274-peptide, can still undergo quantitative K274 autoacetylation. Together, these studies point to the critical and specific role of hMOF Lys-274 autoacetylation in hMOF stability and cognate substrate acetylation and argues that binding of Ac-CoA to hMOF likely drives Lys-274 autoacetylation for subsequent cognate substrate acetylation.« less

Structure of Gremlin-2 in Complex with GDF5 Gives Insight into DAN-Family-Mediated BMP Antagonism.

PubMed

Nolan, Kristof; Kattamuri, Chandramohan; Rankin, Scott A; Read, Randy J; Zorn, Aaron M; Thompson, Thomas B

2016-08-23

The DAN family, including Gremlin-1 and Gremlin-2 (Grem1 and Grem2), represents a large family of secreted BMP (bone morphogenetic protein) antagonists. However, how DAN proteins specifically inhibit BMP signaling has remained elusive. Here, we report the structure of Grem2 bound to GDF5 at 2.9-Å resolution. The structure reveals two Grem2 dimers binding perpendicularly to each GDF5 monomer, resembling an H-like structure. Comparison to the unbound Grem2 structure reveals a dynamic N terminus that undergoes significant transition upon complex formation, leading to simultaneous interaction with the type I and type II receptor motifs on GDF5. Binding studies show that DAN-family members can interact with BMP-type I receptor complexes, whereas Noggin outcompetes the type I receptor for ligand binding. Interestingly, Grem2-GDF5 forms a stable aggregate-like structure in vitro that is not clearly observed for other antagonists, including Noggin and Follistatin. These findings exemplify the structural and functional diversity across the various BMP antagonist families. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

Two divergent endo-beta-1,4-glucanase genes exhibit overlapping expression in ripening fruit and abscising flowers.

PubMed Central

Lashbrook, C C; Gonzalez-Bosch, C; Bennett, A B

1994-01-01

Two structurally divergent endo-beta-1,4-glucanase (EGase) cDNAs were cloned from tomato. Although both cDNAs (Cel1 and Cel2) encode potentially glycosylated, basic proteins of 51 to 53 kD and possess multiple amino acid domains conserved in both plant and microbial EGases, Cel1 and Cel2 exhibit only 50% amino acid identity at the overall sequence level. Amino acid sequence comparisons to other plant EGases indicate that tomato Cel1 is most similar to bean abscission zone EGase (68%), whereas Cel2 exhibits greatest sequence identity to avocado fruit EGase (57%). Sequence comparisons suggest the presence of at least two structurally divergent EGase families in plants. Unlike ripening avocado fruit and bean abscission zones in which a single EGase mRNA predominates, EGase expression in tomato reflects the overlapping accumulation of both Cel1 and Cel2 transcripts in ripening fruit and in plant organs undergoing cell separation. Cel1 mRNA contributes significantly to total EGase mRNA accumulation within plant organs undergoing cell separation (abscission zones and mature anthers), whereas Cel2 mRNA is most abundant in ripening fruit. The overlapping expression of divergent EGase genes within a single species may suggest that multiple activities are required for the cooperative disassembly of cell wall components during fruit ripening, floral abscission, and anther dehiscence. PMID:7994180

Mass spectrometric characterization of human serum albumin dimer: A new potential biomarker in chronic liver diseases.

PubMed

Naldi, Marina; Baldassarre, Maurizio; Nati, Marina; Laggetta, Maristella; Giannone, Ferdinando Antonino; Domenicali, Marco; Bernardi, Mauro; Caraceni, Paolo; Bertucci, Carlo

2015-08-10

Human serum albumin (HSA) undergoes several structural alterations affecting its properties in pro-oxidant and pro-inflammatory environments, as it occurs during liver cirrhosis. These modifications include the formation of albumin dimers. Although HSA dimers were reported to be an oxidative stress biomarker, to date nothing is known about their role in liver cirrhosis and related complications. Additionally, no high sensitive analytical method was available for HSA dimers assessment in clinical settings. Thus the HSA dimeric form in human plasma was characterized by mass spectrometry using liquid chromatography tandem mass spectrometry (LC-ESI-Q-TOF) and matrix assisted laser desorption time of flight (MALDI-TOF) techniques. N-terminal and C-terminal truncated HSA, as well as the native HSA, undergo dimerization by binding another HSA molecule. This study demonstrated the presence of both homo- and hetero-dimeric forms of HSA. The dimerization site was proved to be at Cys-34, forming a disulphide bridge between two albumin molecules, as determined by LC-MS analysis after tryptic digestion. Interestingly, when plasma samples from cirrhotic subjects were analysed, the dimer/monomer ratio resulted significantly increased when compared to that of healthy subjects. These isoforms could represent promising biomarkers for liver disease. Additionally, this analytical approach leads to the relative quantification of the residual native HSA, with fully preserved structural integrity. Copyright © 2014 Elsevier B.V. All rights reserved.

Thermal, spectroscopic and structural characterization of isostructural phase transition in 4-hydroxybenzaldehyde

NASA Astrophysics Data System (ADS)

Panicker, Lata

2018-05-01

Polycrystalline samples of 4-hydroxybenzaldehyde (4-HOBAL) were investigated using differential scanning calorimeter (DSC), Raman spectroscopy and X-ray powder diffraction. The DSC data indicated that 4-HOBAL on heating undergoes a polymorphic transformation from polymorph I to polymorph II. The polymorph II formed remains metastable at ambient condition and transforms to polymorph I when annealed at ambient temperature for more than seven days. The structural information of polymorphs I and II obtained using its X-ray powder diffraction patterns indicated that 4-HOBAL undergoes an isostructural phase transition from polymorph I (monoclinic, P21/c) to polymorph II (monoclinic, P21/c). Raman data suggest that this structural change is associated with some change in its molecular interactions. Thus, in 4-HOBAL the polymorphic phase transformation (II to I) even though energetically favoured is kinetically hindered.

Food web structure and the evolution of ecological communities

NASA Astrophysics Data System (ADS)

Quince, Christopher; Higgs, Paul G.; McKane, Alan J.

Simulations of the coevolution of many interacting species are performed using the Webworld model. The model has a realistic set of predator-prey equations that describe the population dynamics of the species for any structure of the food web. The equations account for competition between species for the same resources, and for the diet choice of predators between alternative prey according to an evolutionarily stable strategy. The set of species present undergoes long-term evolution d ue to speciation and extinction events. We summarize results obtained on the macro-evolutionary dynamics of speciations and extinctions, and on the statistical properties of the food webs that are generated by the model. Simulations begin from small numbers of species and build up to larger webs with relatively constant species number on average. The rate of origination and extinction of species are relatively high, but remain roughly balanced throughout the simulations. When a 'parent' species undergoes sp eciation, the 'child' species usually adds to the same trophic level as the parent. The chance of the child species surviving is significantly higher if the parent is on the second or third trophic level than if it is on the first level, most likely due to a wider choice of possible prey for species on higher levels. Addition of a new species sometimes causes extinction of existing species. The parent species has a high probability of extinction because it has strong competition with the new species. Non-pa rental competitors of the new species also have a significantly higher extinction probability than average, as do prey of the new species. Predators of the new species are less likely than average to become extinct.

An Algorithmic, Pie-Crusting Medial Soft Tissue Release Reduces the Need for Constrained Inserts Patients With Severe Varus Deformity Undergoing Total Knee Arthroplasty.

PubMed

Goudarz Mehdikhani, Kaveh; Morales Moreno, Beatriz; Reid, Jeremy J; de Paz Nieves, Ana; Lee, Yuo-Yu; González Della Valle, Alejandro

2016-07-01

We studied the need to use a constrained insert for residual intraoperative instability and the 1-year result of patients undergoing total knee arthroplasty (TKA) for a varus deformity. In a control group, a "classic" subperiosteal release of the medial soft tissue sleeve was performed as popularized by pioneers of TKA. In the study group, an algorithmic approach that selectively releases and pie-crusts posteromedial structures in extension and anteromedial structures in flexion was used. All surgeries were performed by a single surgeon using measured resection technique, and posterior-stabilized, cemented implants. There were 228 TKAs in the control group and 188 in the study group. Outcome variables included the use of a constrained insert, and the Knee Society Score at 6 weeks, 4 months, and 1 year postoperatively. The effect of the release technique on use of constrained inserts and clinical outcomes were analyzed in a multivariate model controlling for age, sex, body mass index, and severity of deformity. The use of constrained inserts was significantly lower in study than in control patients (8% vs 18%; P = .002). There was no difference in the Knee Society Score and range of motion between the groups at last follow-up. No patient developed postoperative medial instability. This algorithmic, pie-crusting release technique resulted in a significant reduction in the use of constrained inserts with no detrimental effects in clinical results, joint function, and stability. As constrained TKA implants are more costly than nonconstrained ones, if the adopted technique proves to be safe in the long term, it may cause a positive shift in value for hospitals and cost savings in the health care system. Copyright © 2016 Elsevier Inc. All rights reserved.

Outpatient versus Inpatient Primary Cleft Lip and Palate Surgery: Analysis of Early Complications.

PubMed

Kantar, Rami S; Cammarata, Michael J; Rifkin, William J; Plana, Natalie M; Diaz-Siso, J Rodrigo; Flores, Roberto L

2018-05-01

Fiscal constraints are driving shorter hospital lengths of stay. Outpatient primary cleft lip surgery has been shown to be safe, but outpatient primary cleft palate surgery remains controversial. This study evaluates outcomes following outpatient versus inpatient primary cleft lip and palate surgery. The American College of Surgeons National Surgical Quality Improvement Program Pediatric database was used to identify patients undergoing primary cleft lip and palate surgery between 2012 and 2015. Patient clinical factors and 30-day complications were compared for outpatient versus inpatient primary cleft lip and palate surgery. Univariate and multivariate analyses were performed. Three thousand one hundred forty-two patients were included in the primary cleft lip surgery group and 4191 in the primary cleft palate surgery group. Patients in the cleft lip surgery group with structural pulmonary abnormalities had a significantly longer hospital length of stay (β, 4.94; p = 0.001). Patients undergoing outpatient surgery had a significantly higher risk of superficial (OR, 1.99; p = 0.01) and deep wound dehiscence (OR, 2.22; p = 0.01), and were at a significantly lower risk of reoperation (OR, 0.36; p = 0.04) and readmission (OR, 0.52; p = 0.02). Outpatient primary cleft lip surgery is safe and has a complication profile similar to that of inpatient surgery. Outpatient primary cleft palate surgery is common practice in many U.S. hospitals and has a significantly higher rate of wound complications, and lower rates of reoperation and readmission. In properly selected patients, outpatient palatoplasty can be performed safely. Therapeutic, III.

Alpha-Helical Protein Networks Are Self-Protective and Flaw-Tolerant

PubMed Central

Ackbarow, Theodor; Sen, Dipanjan; Thaulow, Christian; Buehler, Markus J.

2009-01-01

Alpha-helix based protein networks as they appear in intermediate filaments in the cell’s cytoskeleton and the nuclear membrane robustly withstand large deformation of up to several hundred percent strain, despite the presence of structural imperfections or flaws. This performance is not achieved by most synthetic materials, which typically fail at much smaller deformation and show a great sensitivity to the existence of structural flaws. Here we report a series of molecular dynamics simulations with a simple coarse-grained multi-scale model of alpha-helical protein domains, explaining the structural and mechanistic basis for this observed behavior. We find that the characteristic properties of alpha-helix based protein networks are due to the particular nanomechanical properties of their protein constituents, enabling the formation of large dissipative yield regions around structural flaws, effectively protecting the protein network against catastrophic failure. We show that the key for these self protecting properties is a geometric transformation of the crack shape that significantly reduces the stress concentration at corners. Specifically, our analysis demonstrates that the failure strain of alpha-helix based protein networks is insensitive to the presence of structural flaws in the protein network, only marginally affecting their overall strength. Our findings may help to explain the ability of cells to undergo large deformation without catastrophic failure while providing significant mechanical resistance. PMID:19547709

A human transcription factor in search mode.

PubMed

Hauser, Kevin; Essuman, Bernard; He, Yiqing; Coutsias, Evangelos; Garcia-Diaz, Miguel; Simmerling, Carlos

2016-01-08

Transcription factors (TF) can change shape to bind and recognize DNA, shifting the energy landscape from a weak binding, rapid search mode to a higher affinity recognition mode. However, the mechanism(s) driving this conformational change remains unresolved and in most cases high-resolution structures of the non-specific complexes are unavailable. Here, we investigate the conformational switch of the human mitochondrial transcription termination factor MTERF1, which has a modular, superhelical topology complementary to DNA. Our goal was to characterize the details of the non-specific search mode to complement the crystal structure of the specific binding complex, providing a basis for understanding the recognition mechanism. In the specific complex, MTERF1 binds a significantly distorted and unwound DNA structure, exhibiting a protein conformation incompatible with binding to B-form DNA. In contrast, our simulations of apo MTERF1 revealed significant flexibility, sampling structures with superhelical pitch and radius complementary to the major groove of B-DNA. Docking these structures to B-DNA followed by unrestrained MD simulations led to a stable complex in which MTERF1 was observed to undergo spontaneous diffusion on the DNA. Overall, the data support an MTERF1-DNA binding and recognition mechanism driven by intrinsic dynamics of the MTERF1 superhelical topology. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

Factors That Influence the Decision to Undergo Labiaplasty: Media, Relationships, and Psychological Well-Being.

PubMed

Sharp, Gemma; Tiggemann, Marika; Mattiske, Julie

2016-04-01

An increasing number of women are undergoing labiaplasty procedures; however, very little is known about the psychological factors that motivate women to seek out this procedure. To investigate the factors that influence women's decisions to undergo labiaplasty. Women seeking to undergo labiaplasty (n = 35) were compared with women who were not (n = 30). Standardized measures were employed to assess the patients' media exposure (television, the Internet, advertising, pornography), relationship quality, and psychological well-being. Women's motivations for deciding to undergo a labiaplasty procedure were characterized as "appearance," "functional," "sexual," or "psychological" motivations, with concerns about the labia's appearance being the most commonly reported motivation. Correspondingly, women seeking labiaplasty were significantly less satisfied with the appearance of their genitals than the comparison group (P < .001). These women had also experienced greater exposure to images of female genitalia on the Internet (P = .004) and in advertisements (P = .021), and had internalized these images to a greater extent (P = .010). There were no differences between the two groups on the measures of relationship quality. However, significantly fewer of the women seeking to undergo a labiaplasty procedure were involved in a romantic relationship at the time of the study (P = .039). There were also no differences between the two groups on the measures of psychological well-being, except that women seeking to undergo labiaplasty were less satisfied with their lives overall (P = .027). The findings identified media exposure and relationship status as important factors that influence women's decisions to undergo labiaplasty. 3 Risk. © 2016 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com.

Structural transformations in high-capacity Li 2Cu 0.5Ni 0.5O 2 cathodes

DOE PAGES

Ruther, Rose E.; Pandian, Amaresh Samuthira; Yan, Pengfei; ...

2017-03-09

Cathode materials that can cycle >1 Li + per transition metal are of substantial interest for increasing the overall energy density of lithium-ion batteries. Li 2Cu 0.5Ni 0.5O 2 has a very high theoretical capacity of ~500 mAh/g assuming both Li+ ions are cycled reversibly. The Cu 2+/3+ and Ni 2+/3+/4+ redox couples are also at high voltage, which could further boost the energy density of this system. Despite such promise, Li 2Cu 0.5Ni 0.5O 2 undergoes irreversible phase changes during charge (delithiation) that result in large first-cycle irreversible loss and poor long-term cycling stability. Oxygen evolves before the Cumore » 2+/3+ or Ni 3+/4+ transitions are accessed. In this contribution, X-ray diffraction, transmission electron microscopy (TEM), and transmission X-ray microscopy combined with X-ray absorption near edge structure (TXM–XANES) are used to follow the chemical and structural changes that occur in Li 2Cu 0.5Ni 0.5O 2 during electrochemical cycling. Li 2Cu 0.5Ni 0.5O 2 is a solid solution of orthorhombic Li2CuO2 and Li2NiO2, but the structural changes more closely mimic the changes that the Li 2NiO 2 endmember undergoes. Li 2Cu 0.5Ni 0.5O 2 loses long-range order during charge, but TEM analysis provides clear evidence of particle exfoliation and the transformation from orthorhombic to a partially layered structure. Linear combination fitting and principal component analysis of TXM–XANES are used to map the different phases that emerge during cycling ex situ and in situ. Lastly, significant changes in the XANES at the Cu and Ni K-edges correlate with the onset of oxygen evolution.« less

Parent Expectations Mediate Outcomes for Young Adults with Autism Spectrum Disorder.

PubMed

Kirby, Anne V

2016-05-01

Understanding the complex relationships among factors that may predict the outcomes of young adults with autism spectrum disorder (ASD) is of utmost importance given the increasing population undergoing and anticipating the transition to adulthood. With a sample of youth with ASD (n = 1170) from the National Longitudinal Transition Study-2, structural equation modeling techniques were used to test parent expectations as a mediator of young adult outcomes (i.e., employment, residential independence, social participation) in a longitudinal analysis. The mediation hypothesis was confirmed; family background and functional performance variables significantly predicted parent expectations which significantly predicted outcomes. These findings add context to previous studies examining the role of parent expectations on young adult outcomes and inform directions for family-centered interventions and future research.

Flexible Animation Computer Program

NASA Technical Reports Server (NTRS)

Stallcup, Scott S.

1990-01-01

FLEXAN (Flexible Animation), computer program animating structural dynamics on Evans and Sutherland PS300-series graphics workstation with VAX/VMS host computer. Typical application is animation of spacecraft undergoing structural stresses caused by thermal and vibrational effects. Displays distortions in shape of spacecraft. Program displays single natural mode of vibration, mode history, or any general deformation of flexible structure. Written in FORTRAN 77.

Iliac artery stenting in patients with poor distal runoff: Influence of concomitant infrainguinal arterial reconstruction.

PubMed

Timaran, Carlos H; Ohki, Takao; Gargiulo, Nicholas J; Veith, Frank J; Stevens, Scott L; Freeman, Michael B; Goldman, Mitchell H

2003-09-01

Inadequate infrainguinal runoff is considered an important risk factor for iliac stent failure. However, the influence of concomitant infrainguinal arterial reconstruction (CIAR) on iliac stent patency is unknown. This study evaluated the influence of CIAR on outcome of iliac angioplasty and stenting (IAS) in patients with poor distal runoff. Over 5 years (1996 to 2001), 68 IAS procedures (78 stents) were performed in 62 patients with poor distal runoff (angiographic runoff score >or=5). The SVS/AAVS reporting standards were followed to define outcome variables and risk factors. Data were analyzed with both univariate analysis (Kaplan-Meier method [K-M]) and regression analysis (Cox proportional hazards model). Indications for iliac artery stenting were disabling claudication (59%) and limb salvage (41%). Of the 68 procedures, IAS with CIAR was performed in 31 patients (46%), and IAS alone was performed in 37 patients (54%). Patients undergoing IAS with CIAR were older (P =.03) and had more extensive and multifocal iliac artery occlusive disease, with more TASC (TransAtlantic Inter-Society Consensus) type C lesions (P =.03), compared with patients undergoing IAS alone. No other significant differences in risk factors were noted. Runoff scores between patients undergoing IAS with CIAR and those undergoing IAS alone were not significantly different (median runoff scores, 6 [range, 5-8] and 7 [range, 5-9], respectively; P =.77). Primary stent patency rate at 1, 3, and 5 years was 87%, 54%, and 42%, respectively, for patients undergoing IAS with CIAR, and was 76%, 66%, and 55%, respectively, for patients undergoing IAS. Univariate analysis revealed that primary stent patency rate was not significantly different between the 2 groups (K-M, log-rank test, P =.81). Primary graft patency rate for CIAR was 81%, 52%, and 46% at 1, 3, and 5 years, respectively. Performing CIAR did not affect primary iliac stent patency (relative risk, 1.1; 95% confidence interval, 0.49-2.47; P =.81). Overall, there was a trend toward improved limb salvage in patients undergoing IAS with CIAR, compared with those undergoing IAS alone (K-M, log rank test, P =.07). In patients undergoing IAS with poor distal runoff, CIAR does not improve iliac artery stent patency. Infrainguinal bypass procedures should therefore be reserved for patients who do not demonstrate clinical improvement and possibly for those with limb-threatening ischemia.

[Effect of Supportan on nutritional status and immune function of late-staged gastric cancer patients undergoing chemotherapy].

PubMed

Zhong, Hai-jun; Ying, Jie-er; Ma, Sheng-lin

2006-09-01

To evaluate the effect of Supportan, an enteral nutrition (EN) specific for tumor patients, on the nutritional status and immune function of late-staged gastric cancer patients undergoing chemotherapy. Sixty-six late-staged gastric cancer patients undergoing chemotherapy were randomly divided into EN group (n=33) and control group (n=33). During chemotherapy, the patients in EN group received Supportan and the patients in the control group received basic diet. On the 14th day before chemotherapy and after chemotherapy, nutritional status and cell immune indicators were evaluated. As for nutrition indicators, there were no significant differences in EN group before and after chemotherapy (P > 0.05). Total protein, hemoglobin, prealbumin and transferrin significantly decreased after chemotherapy compared with those before chemotherapy in the control group (P< 0.01). The levels of CD4(+), CD8(+) T cells and CD4/CD8 were significantly increased, and NK cells, serum levels of IL-1, IL-6 were significantly decreased after chemotherapy in EN group (P< 0.01). The levels of IL-6 and TNF-alpha were significantly higher after chemotherapy than those before chemotherapy in the control group(P< 0.01). Curative effects of immune nutrition in EN group were superior to that in the control group, however, the differences were not statistically significant. The incidences of nausea, vomiting and marrow inhibition in Supportan group was lower compared with those in the control group, but with no significant difference. Supportan can prevent malnutrition of the late-staged gastric cancer patients undergoing chemotherapy, and improve immune function and alleviate adverse effects of chemotherapy.

Role of Halides in the Ordered Structure Transitions of Heated Gold Nanocrystal Superlattices

PubMed Central

2015-01-01

Dodecanethiol-capped gold (Au) nanocrystal superlattices can undergo a surprisingly diverse series of ordered structure transitions when heated (Goodfellow, B. W.; Rasch, M. R.; Hessel, C. M.; Patel, R. N.; Smilgies, D.-M.; Korgel, B. A. Nano Lett.2013, 13, 5710–5714). These are the result of highly uniform changes in nanocrystal size, which subsequently force a spontaneous rearrangement of superlattice structure. Here, we show that halide-containing surfactants play an essential role in these transitions. In the absence of any halide-containing surfactant, superlattices of dodecanethiol-capped (1.9-nm-diameter) Au nanocrystals do not change size until reaching about 190–205 °C, at which point the gold cores coalesce. In the presence of halide-containing surfactant, such as tetraoctylphosphonium bromide (TOPB) or tetraoctylammounium bromide (TOAB), the nanocrystals ripen at much lower temperature and superlattices undergo various ordered structure transitions upon heating. Chloride- and iodide-containing surfactants induce similar behavior, destabilizing the Au–thiol bond and reducing the thermal stability of the nanocrystals. PMID:26013597

An origin of arc structures deeply embedded in dense molecular cloud cores

NASA Astrophysics Data System (ADS)

Matsumoto, Tomoaki; Onishi, Toshikazu; Tokuda, Kazuki; Inutsuka, Shu-ichiro

2015-04-01

We investigated the formation of arc-like structures in the infalling envelope around protostars, motivated by the recent Atacama Large Millimeter/Submillimeter Array (ALMA) observations of the high-density molecular cloud core, MC27/L1521F. We performed self-gravitational hydrodynamical numerical simulations with an adaptive mesh refinement code. A filamentary cloud with a 0.1 pc width fragments into cloud cores because of perturbations due to weak turbulence. The cloud core undergoes gravitational collapse to form multiple protostars, and gravitational torque from the orbiting protostars produces arc structures extending up to a 1000 au scale. As well as on a spatial extent, the velocity ranges of the arc structures, ˜0.5 km s-1, are in agreement with the ALMA observations. We also found that circumstellar discs are often misaligned in triple system. The misalignment is caused by the tidal interaction between the protostars when they undergo close encounters because of a highly eccentric orbit of the tight binary pair.

Crystal structure of a complex between the phosphorelay protein YPD1 and the response regulator domain of SLN1 bound to a phosphoryl analog

PubMed Central

Zhao, Xiaodong; Copeland, Daniel M.; Soares, Alexei S.; West, Ann H.

2008-01-01

Summary The crystal structure of the yeast SLN1 response regulator domain bound to both a phosphoryl analog (BeF3−) and Mg2+ ion in complex with its downstream phosphorelay signaling partner YPD1 has been determined at a resolution of 1.70 Å. Comparisons between the beryllium fluoride-activated complex and the unliganded (or apo) complex determined previously reveal modest but important differences. The SLN1-R1•Mg2+•BeF3− structure from the complex provides evidence for the first time that the mechanism of phosphorylation-induced activation is highly conserved between bacterial response regulator domains and this example from a eukaryotic organism. Residues in and around the active site undergo slight rearrangements in order to form bonds to the essential divalent cation and fluorine atoms of BeF3−. Two conserved switch-like residues (Thr 1173 and Phe 1192) occupy distinctly different positions in the apo- versus BeF3−-bound structures consistent with the “Y-T” coupling mechanism proposed for activation of CheY and other bacterial response regulators. Several loop regions and the α4-β5-α5 surface of the SLN1-R1 domain undergo subtle conformational changes (∼1-3 Å displacements relative to the apo-structure) that lead to significant changes in terms of contacts that are formed with YPD1. Detailed structural comparisons of protein-protein interactions in the apo- and BeF3−-bound complexes suggest at least a two-state equilibrium model for formation of a transient encounter complex, in which phosphorylation of the response regulator promotes the formation of a phosphotransfer-competent complex. In the BeF3−-activated complex, the position of His 64 from YPD1 is within ideal distance and near linear geometry with Asp 1144 from the SLN1-R1 domain for phosphotransfer to occur. The ground state structure presented here suggests that phosphoryl transfer will likely proceed through an associative mechanism involving formation of a pentacoordinate phosphorus intermediate. PMID:18076904

The Influence of Oral Carbohydrate Solution Intake on Stress Response before Total Hip Replacement Surgery during Epidural and General Anaesthesia.

PubMed

Çeliksular, M Cem; Saraçoğlu, Ayten; Yentür, Ercüment

2016-06-01

The effects of oral carbohydrate solutions, ingested 2 h prior to operation, on stress response were studied in patients undergoing general or epidural anaesthesia. The study was performed on 80 ASA I-II adult patients undergoing elective total hip replacement, which were randomized to four groups (n=20). Group G patients undergoing general anaesthesia fasted for 8 h preoperatively; Group GN patients undergoing general anaesthesia drank oral carbohydrate solutions preoperatively; Group E patients undergoing epidural anaesthesia fasted for 8 h and Group EN patients undergoing epidural anaesthesia drank oral carbohydrate solutions preoperatively. Groups GN and EN drank 800 mL of 12.5% oral carbohydrate solution at 24:00 preoperatively and 400 mL 2 h before the operation. Blood samples were taken for measurements of glucose, insulin, cortisol and IL-6 levels. The effect of preoperative oral carbohydrate ingestion on blood glucose levels was not significant. Insulin levels 24 h prior to surgery were similar; however, insulin levels measured just before surgery were 2-3 times higher in groups GN and EN than in groups G and E. Insulin levels at the 24(th) postoperative hour in epidural groups were increased compared to those at basal levels, although general anaesthesia groups showed a decrease. From these measurements, only the change in Group EN was statistically significant (p<0.05). Plasma cortisol levels at the 2(nd) peroperative hour were higher in epidural groups than in general anaesthesia groups. Both anaesthesia techniques did not have an effect on IL-6 levels. We concluded that epidural anaesthesia suppressed stress response, although preoperative oral carbohydrate nutrition did not reveal a significant effect on surgical stress response.

Fibrin network changes in neonates after cardiopulmonary bypass

PubMed Central

Brown, Ashley C.; Hannan, Riley; Timmins, Lucas H.; Fernandez, Janet D.; Barker, Thomas H.; Guzzetta, Nina A.

2016-01-01

Background Quantitative and qualitative differences exist between the hemostatic systems of neonates and adults, among them the presence of ‘fetal’ fibrinogen, a qualitatively dysfunctional form of fibrinogen that exists until one year of age. The consequences of ‘fetal’ fibrinogen on clot structure in neonates, particularly in the context of surgical associated bleeding, have not been well characterized. Here we examine the sequential changes in clotting components and resultant clot structure in a small sample of neonates undergoing cardiac surgery and cardiopulmonary bypass (CPB). Methods Blood samples were collected from neonates (n=10) before surgery, immediately after CPB and following the transfusion of cryoprecipitate (i.e. adult fibrinogen component). Clots were formed from patient samples or purified neonatal and adult fibrinogen. Clot structure was analyzed using confocal microscopy. Results Clots formed from plasma obtained after CPB and after transfusion were more porous than baseline clots. Analysis of clots formed from purified neonatal and adult fibrinogen, demonstrated that at equivalent fibrinogen concentrations, neonatal clots lack three-dimensional structure while adult clots were denser with significant three-dimensional structure. Clots formed from a combination of purified neonatal and adult fibrinogen were less homogenous than those formed from either purified adult or neonatal fibrinogen. Conclusions Our results confirm that significant differences exist in clot structure between neonates and adults, and that neonatal and adult fibrinogen may not integrate well. These findings suggest that differential treatment strategies for neonates should be pursued to reduce the demonstrated morbidity of blood product transfusion. PMID:26914227

Factors influencing behavioral intention to undergo Papanicolaou testing in early adulthood: Comparison of Japanese and Korean women.

PubMed

Kang, Kyung-Ah; Kim, Shin-Jeong; Kaneko, Noriyo

2017-12-01

In this study, we identified the factors influencing behavioral intention to undergo Papanicolaou testing among Japanese and Korean women in early adulthood. Their behavioral intentions were compared in this cross-sectional descriptive study. In total, 887 women (Japanese = 498, Korean = 389) aged 20-39 years participated in this study. Using a self-report questionnaire, knowledge, attitudes, subjective norm, perceived behavioral control, and behavioral intention were surveyed. There were significant differences between Japanese and Korean women's scores on all main variables. For Japanese women, all the variables moderately correlated with behavioral intention. In comparison, for Korean women, all independent variables, except for knowledge, moderately correlated with behavioral intention. Through a multiple regression analysis, age, undergoing Papanicolaou testing, attitudes, subjective norm, and perceived behavioral control were identified as significant predictors of behavioral intention among Japanese women. Among Korean women, job status, undergoing a Papanicolaou test, attitudes, subjective norm, and perceived behavioral control were demonstrated as significant predictors of behavioral intention. Health professionals should consider these factors to encourage Papanicolaou testing in women in early adulthood. © 2017 John Wiley & Sons Australia, Ltd.

Activator Protein-1: redox switch controlling structure and DNA-binding.

PubMed

Yin, Zhou; Machius, Mischa; Nestler, Eric J; Rudenko, Gabby

2017-11-02

The transcription factor, activator protein-1 (AP-1), binds to cognate DNA under redox control; yet, the underlying mechanism has remained enigmatic. A series of crystal structures of the AP-1 FosB/JunD bZIP domains reveal ordered DNA-binding regions in both FosB and JunD even in absence DNA. However, while JunD is competent to bind DNA, the FosB bZIP domain must undergo a large conformational rearrangement that is controlled by a 'redox switch' centered on an inter-molecular disulfide bond. Solution studies confirm that FosB/JunD cannot undergo structural transition and bind DNA when the redox-switch is in the 'OFF' state, and show that the mid-point redox potential of the redox switch affords it sensitivity to cellular redox homeostasis. The molecular and structural studies presented here thus reveal the mechanism underlying redox-regulation of AP-1 Fos/Jun transcription factors and provide structural insight for therapeutic interventions targeting AP-1 proteins. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Two-soliton interaction as an elementary act of soliton turbulence in integrable systems

NASA Astrophysics Data System (ADS)

Pelinovsky, E. N.; Shurgalina, E. G.; Sergeeva, A. V.; Talipova, T. G.; El, G. A.; Grimshaw, R. H. J.

2013-01-01

Two-soliton interactions play a definitive role in the formation of the structure of soliton turbulence in integrable systems. To quantify the contribution of these interactions to the dynamical and statistical characteristics of the nonlinear wave field of soliton turbulence we study properties of the spatial moments of the two-soliton solution of the Korteweg-de Vries (KdV) equation. While the first two moments are integrals of the KdV evolution, the 3rd and 4th moments undergo significant variations in the dominant interaction region, which could have strong effect on the values of the skewness and kurtosis in soliton turbulence.

The Correlation Entropy as a Measure of the Complexity of High-Lying Single-Particle Modes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stoyanov, Chavdar; Zelevinsky, Vladimir; Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824-1321

Highly-excited single-particle states in nuclei are coupled with the excitations of a more complex character, first of all with collective phonon-like modes of the core. In the framework of the quasiparticle-phonon model we consider the structure of resulting complex configurations using the 1k17/2 orbital in 209Pb as an example. The eigenstates of the model carry significant degree of complexity that can be quantified with the aid of correlational invariant entropy. With artificially enhanced particle-core coupling, the system undergoes the doubling phase transition with the quasiparticle strength concentrated in two repelling peaks.

Considering Cannabis: The Effects of Regular Cannabis Use on Neurocognition in Adolescents and Young Adults

PubMed Central

Lisdahl, Krista M.; Wright, Natasha E.; Kirchner-Medina, Christopher; Maple, Kristin E.; Shollenbarger, Skyler

2014-01-01

Thirty-six percent of high school seniors have used cannabis in the past year, and an alarming 6.5% smoked cannabis daily, up from 2.4% in 1993 (Johnston et al., 2013). Adolescents and emerging adults are undergoing significant neurodevelopment and animal studies suggest they may be particularly vulnerable to negative drug effects. In this review, we will provide a detailed overview of studies outlining the effects of regular (at least weekly) cannabis use on neurocognition, including studies outlining cognitive, structural and functional findings. We will also explore the public health impact of this research. PMID:25013751

Bone marrow amyloid spherulites in a case of AL amyloidosis.

PubMed

Bommannan B K, Karthik; Sonai, Mukinkumar; Sachdeva, Man Updesh Singh

2016-05-01

Parallel arrangement of β-pleated sheets by amyloidogenic proteins is a well known phenomenon. Rarely, amyloid fibrils undergo radial orientation to form globular structures called spherulites. These amyloid spherulites show Maltese cross pattern under polarized microscopy. The clinical significance of amyloid spherulites is undetermined. Amyloidogenic proteins like insulin and β-lactoglobulin form spherulites in vitro. The senile plaques of Alzheimer's disease rarely form in vivo spherulites. Amyloid spherulites have been described in the liver and small intestine. For the first time, we document amyloid spherulite formation in the bone marrow biopsy of an AL amyloidosis patient. Copyright © 2016 Elsevier Inc. All rights reserved.

Real-time monitoring system of composite aircraft wings utilizing Fibre Bragg Grating sensor

NASA Astrophysics Data System (ADS)

Vorathin, E.; Hafizi, Z. M.; Che Ghani, S. A.; Lim, K. S.

2016-10-01

Embedment of Fibre Bragg Grating (FBG) sensor in composite aircraft wings leads to the advancement of structural condition monitoring. The monitored aircraft wings have the capability to give real-time response under critical loading circumstances. The main objective of this paper is to develop a real-time FBG monitoring system for composite aircraft wings to view real-time changes when the structure undergoes some static loadings and dynamic impact. The implementation of matched edge filter FBG interrogation system to convert wavelength variations to strain readings shows that the structure is able to response instantly in real-time when undergoing few loadings and dynamic impact. This smart monitoring system is capable of updating the changes instantly in real-time and shows the weight induced on the composite aircraft wings instantly without any error. It also has a good agreement with acoustic emission (AE) sensor in the dynamic test.

Population structuring of multi-copy, antigen-encoding genes in Plasmodium falciparum

PubMed Central

Artzy-Randrup, Yael; Rorick, Mary M; Day, Karen; Chen, Donald; Dobson, Andrew P; Pascual, Mercedes

2012-01-01

The coexistence of multiple independently circulating strains in pathogen populations that undergo sexual recombination is a central question of epidemiology with profound implications for control. An agent-based model is developed that extends earlier ‘strain theory’ by addressing the var gene family of Plasmodium falciparum. The model explicitly considers the extensive diversity of multi-copy genes that undergo antigenic variation via sequential, mutually exclusive expression. It tracks the dynamics of all unique var repertoires in a population of hosts, and shows that even under high levels of sexual recombination, strain competition mediated through cross-immunity structures the parasite population into a subset of coexisting dominant repertoires of var genes whose degree of antigenic overlap depends on transmission intensity. Empirical comparison of patterns of genetic variation at antigenic and neutral sites supports this role for immune selection in structuring parasite diversity. DOI: http://dx.doi.org/10.7554/eLife.00093.001 PMID:23251784

Structural phases arising from reconstructive and isostructural transitions in high-melting-point oxides under hydrostatic pressure: A first-principles study

NASA Astrophysics Data System (ADS)

Tian, Hao; Kuang, Xiao-Yu; Mao, Ai-Jie; Yang, Yurong; Xu, Changsong; Sayedaghaee, S. Omid; Bellaiche, L.

2018-01-01

High-melting-point oxides of chemical formula A B O3 with A =Ca , Sr, Ba and B =Zr , Hf are investigated as a function of hydrostatic pressure up to 200 GPa by combining first-principles calculations with a particle swarm optimization method. Ca- and Sr-based systems: (1) first undergo a reconstructive phase transition from a perovskite state to a novel structure that belongs to the post-post-perovskite family and (2) then experience an isostructural transition to a second, also new post-post-perovskite state at higher pressures, via the sudden formation of a specific out-of-plane B -O bond. In contrast, the studied Ba compounds evolve from a perovskite phase to a third novel post-post-perovskite structure via another reconstructive phase transition. The original characteristics of these three different post-post-perovskite states are emphasized. Unusual electronic properties, including significant piezochromic effects and an insulator-metal transition, are also reported and explained.

Structural and optical characterization of ZnO/Mg(x)Zn(1-x)O multiple quantum wells based random laser diodes.

PubMed

Jiang, Qike; Zheng, He; Wang, Jianbo; Long, Hao; Fang, Guojia

2012-12-01

Two kinds of laser diodes (LDs) comprised of ZnO/Mg(x)Zn(1-x)O (ZnO/MZO) multiple quantum wells (MQWs) grown on GaN (MQWs/GaN) and Si (MQWs/Si) substrates, respectively, have been constructed. The LD with MQWs/GaN exhibits ultraviolet random lasing under electrical excitation, while that with MQWs/Si does not. In the MQWs/Si, ZnO/MZO MQWs consist of nanoscaled crystallites, and the MZO layers undergo a phase separation of cubic MgO and hexagonal ZnO. Moreover, the Mg atom predominantly locates in the MZO layers along with a significant aggregation at the ZnO/MZO interfaces; in sharp contrast, the ZnO/MZO MQWs in the MQWs/GaN show a well-crystallized structure with epitaxial relationships among GaN, MZO, and ZnO. Notably, Mg is observed to diffuse into the ZnO well layers. The structure-optical property relationship of these two LDs is further discussed.

Approaches to the structural modelling of insect wings.

PubMed Central

Wootton, R J; Herbert, R C; Young, P G; Evans, K E

2003-01-01

Insect wings lack internal muscles, and the orderly, necessary deformations which they undergo in flight and folding are in part remotely controlled, in part encoded in their structure. This factor is crucial in understanding their complex, extremely varied morphology. Models have proved particularly useful in clarifying the facilitation and control of wing deformation. Their development has followed a logical sequence from conceptual models through physical and simple analytical to numerical models. All have value provided their limitations are realized and constant comparisons made with the properties and mechanical behaviour of real wings. Numerical modelling by the finite element method is by far the most time-consuming approach, but has real potential in analysing the adaptive significance of structural details and interpreting evolutionary trends. Published examples are used to review the strengths and weaknesses of each category of model, and a summary is given of new work using finite element modelling to investigate the vibration properties and response to impact of hawkmoth wings. PMID:14561349

Structural differences between yeast and mammalian microtubules revealed by cryo-EM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Howes, Stuart C.; Geyer, Elisabeth A.; LaFrance, Benjamin

Microtubules are polymers of αβ-tubulin heterodimers essential for all eukaryotes. Despite sequence conservation, there are significant structural differences between microtubules assembled in vitro from mammalian or budding yeast tubulin. Yeast MTs were not observed to undergo compaction at the interdimer interface as seen for mammalian microtubules upon GTP hydrolysis. Lack of compaction might reflect slower GTP hydrolysis or a different degree of allosteric coupling in the lattice. The microtubule plus end–tracking protein Bim1 binds yeast microtubules both between αβ-tubulin heterodimers, as seen for other organisms, and within tubulin dimers, but binds mammalian tubulin only at interdimer contacts. At the concentrationsmore » used in cryo-electron microscopy, Bim1 causes the compaction of yeast microtubules and induces their rapid disassembly. In conclusion, our studies demonstrate structural differences between yeast and mammalian microtubules that likely underlie their differing polymerization dynamics. These differences may reflect adaptations to the demands of different cell size or range of physiological growth temperatures.« less

Crystal structure of a suicidal DNA repair protein: the Ada O6-methylguanine-DNA methyltransferase from E. coli.

PubMed

Moore, M H; Gulbis, J M; Dodson, E J; Demple, B; Moody, P C

1994-04-01

The mutagenic and carcinogenic effects of simple alkylating agents are mainly due to methylation at the O6 position of guanine in DNA. O6-methylguanine directs the incorporation of either thymine or cytosine without blocking DNA replication, resulting in GC to AT transition mutations. In prokaryotic and eukaryotic cells antimutagenic repair is effected by direct reversal of this DNA damage. A suicidal methyltransferase repair protein removes the methyl group from DNA to one of its own cysteine residues. The resulting self-methylation of the active site cysteine renders the protein inactive. Here we report the X-ray structure of the 19 kDa C-terminal domain of the Escherichia coli ada gene product, the prototype of these suicidal methyltransferases. In the crystal structure the active site cysteine is buried. We propose a model for the significant conformational change that the protein must undergo in order to bind DNA and effect methyl transfer.

Sperm chromatin structure assay results after swim-up are related only to embryo quality but not to fertilization and pregnancy rates following IVF.

PubMed

Niu, Zhi-Hong; Shi, Hui-Juan; Zhang, Hui-Qin; Zhang, Ai-Jun; Sun, Yi-Juan; Feng, Yun

2011-11-01

The aim of this study was to investigate whether the sperm chromatin structure assay (SCSA) results after swim-up are related to fertilization rates, embryo quality and pregnancy rates following in vitro fertilization (IVF). A total of 223 couples undergoing IVF in our hospital from October 2008 to September 2009 were included in this study. Data on the IVF process and sperm chromatin structure assay results were collected. Fertilization rate, embryo quality and IVF success rates of different DNA fragmentation index (DFI) subgroups and high DNA stainability (HDS) subgroups were compared. There were no significant differences in fertilization rate, clinical pregnancy or delivery rates between the DFI and HDS subgroups. However, the group with abnormal DFI had a lower good embryo rate. So, we concluded that the SCSA variables, either DFI or HDS after swim-up preparation, were not valuable in predicting fertilization failure or pregnancy rate, but an abnormal DFI meant a lower good embryo rate following IVF.

Ontology aided modeling of organic reaction mechanisms with flexible and fragment based XML markup procedures.

PubMed

Sankar, Punnaivanam; Aghila, Gnanasekaran

2007-01-01

The mechanism models for primary organic reactions encoding the structural fragments undergoing substitution, addition, elimination, and rearrangements are developed. In the proposed models, each and every structural component of mechanistic pathways is represented with flexible and fragment based markup technique in XML syntax. A significant feature of the system is the encoding of the electron movements along with the other components like charges, partial charges, half bonded species, lone pair electrons, free radicals, reaction arrows, etc. needed for a complete representation of reaction mechanism. The rendering of reaction schemes described with the proposed methodology is achieved with a concise XML extension language interoperating with the structure markup. The reaction scheme is visualized as 2D graphics in a browser by converting them into SVG documents enabling the desired layouts normally perceived by the chemists conventionally. An automatic representation of the complex patterns of the reaction mechanism is achieved by reusing the knowledge in chemical ontologies and developing artificial intelligence components in terms of axioms.

Gravitational Effects on Near Field Flow Structure of Low Density Gas Jets

NASA Technical Reports Server (NTRS)

Yep, Tze-Wing; Agrawal, Ajay K.; Griffin, DeVon; Salzman, Jack (Technical Monitor)

2001-01-01

Experiments were conducted in Earth gravity and microgravity to acquire quantitative data on near field flow structure of helium jets injected into air. Microgravity conditions were simulated in the 2.2-second drop tower at NASA Glenn Research Center. The jet flow was observed by quantitative rainbow schlieren deflectometry, a non-intrusive line of site measurement technique for the whole field. The flow structure was characterized by distributions of angular deflection and helium mole percentage obtained from color schlieren images taken at 60 Hz. Results show that the jet flow was significantly influenced by the gravity. The jet in microgravity was up to 70 percent wider than that in Earth gravity. The jet flow oscillations observed in Earth gravity were absent in microgravity, providing direct experimental evidence that the flow instability in the low density jet was buoyancy induced. The paper provides quantitative details of temporal flow evolution as the experiment undergoes a change in gravity in the drop tower.

Phase Coexistence and Kinetic Arrest in the Magnetostructural Transition of the Ordered Alloy FeRh

DOE PAGES

Keavney, David J.; Choi, Yongseong; Holt, Martin V.; ...

2018-01-29

In materials where two or more ordering degrees of freedom are closely matched in their free energies, coupling between them, or multiferroic behavior can occur. These phenomena can produce a very rich phase behavior, as well as emergent phases that offer useful properties and opportunities to reveal novel phenomena in phase transitions. The ordered alloy FeRh undergoes an antiferromagnetic to ferromagnetic phase transition at ~375 K, which illustrates the interplay between structural and magnetic order mediated by a delicate energy balance between two configurations. We have examined this transition using a combination of high-resolution x-ray structural and magnetic imaging andmore » comprehensive x-ray magnetic circular dichroism spectroscopy. We find that the transition proceeds via a defect-driven domain nucleation and growth mechanism, with significant return point memory in both the structural and magnetic domain configurations. In conclusion, the domains show evidence of inhibited growth after nucleation, resulting in a quasi- 2nd order temperature behavior.« less

Association of Patient Age at Gastric Bypass Surgery With Long-term All-Cause and Cause-Specific Mortality.

PubMed

Davidson, Lance E; Adams, Ted D; Kim, Jaewhan; Jones, Jessica L; Hashibe, Mia; Taylor, David; Mehta, Tapan; McKinlay, Rodrick; Simper, Steven C; Smith, Sherman C; Hunt, Steven C

2016-07-01

Bariatric surgery is effective in reducing all-cause and cause-specific long-term mortality. Whether the long-term mortality benefit of surgery applies to all ages at which surgery is performed is not known. To examine whether gastric bypass surgery is equally effective in reducing mortality in groups undergoing surgery at different ages. All-cause and cause-specific mortality rates and hazard ratios (HRs) were estimated from a retrospective cohort within 4 categories defined by age at surgery: younger than 35 years, 35 through 44 years, 45 through 54 years, and 55 through 74 years. Mean follow-up was 7.2 years. Patients undergoing gastric bypass surgery seen at a private surgical practice from January 1, 1984, through December 31, 2002, were studied. Data analysis was performed from June 12, 2013, to September 6, 2015. A cohort of 7925 patients undergoing gastric bypass surgery and 7925 group-matched, severely obese individuals who did not undergo surgery were identified through driver license records. Matching criteria included year of surgery to year of driver license application, sex, 5-year age groups, and 3 body mass index categories. Roux-en-Y gastric bypass surgery. All-cause and cause-specific mortality compared between those undergoing and not undergoing gastric bypass surgery using HRs. Among the 7925 patients who underwent gastric bypass surgery, the mean (SD) age at surgery was 39.5 (10.5) years, and the mean (SD) presurgical body mass index was 45.3 (7.4). Compared with 7925 matched individuals not undergoing surgery, adjusted all-cause mortality after gastric bypass surgery was significantly lower for patients 35 through 44 years old (HR, 0.54; 95% CI, 0.38-0.77), 45 through 54 years old (HR, 0.43; 95% CI, 0.30-0.62), and 55 through 74 years old (HR, 0.50; 95% CI, 0.31-0.79; P < .003 for all) but was not lower for those younger than 35 years (HR, 1.22; 95% CI, 0.82-1.81; P = .34). The lack of mortality benefit in those undergoing gastric bypass surgery at ages younger than 35 years primarily derived from a significantly higher number of externally caused deaths (HR, 2.53; 95% CI, 1.27-5.07; P = .009), particularly among women (HR, 3.08; 95% CI, 1.4-6.7; P = .005). Patients undergoing gastric bypass surgery had a significantly lower age-related increase in mortality than severely obese individuals not undergoing surgery (P = .001). Gastric bypass surgery was associated with improved long-term survival for all patients undergoing surgery at ages older than 35 years, with externally caused deaths only elevated in younger women. Gastric bypass surgery is protective against mortality even for older patients and also reduces the age-related increase in mortality observed in severely obese individuals not undergoing surgery.

LaRC-RP41: A Tough, High-Performance Composite Matrix

NASA Technical Reports Server (NTRS)

Pater, Ruth H.; Johnston, Norman J.; Smith, Ricky E.; Snoha, John J.; Gautreaux, Carol R.; Reddy, Rakasi M.

1991-01-01

New polymer exhibits increased toughness and resistance to microcracking. Cross-linking PMR-15 and linear LaRC-TPI combined to provide sequential semi-2-IPN designated as LaRC-RP41. Synthesized from PMR-15 imide prepolymer undergoing cross-linking in immediate presence of LaRC-TPI polyamic acid, also undergoing simultaneous imidization and linear chain extension. Potentially high-temperature matrix resin, adhesive, and molding resin. Applications include automobiles, electronics, aircraft, and aerospace structures.

Endurance with partnership: a preliminary conceptual framework for couples undergoing in vitro fertilisation treatment.

PubMed

Ying, Liying; Wu, Lai Har; Wu, Xiangli; Shu, Jing; Loke, Alice Yuen

2018-04-01

Infertility affects both women and men in the physical, emotional, existential, and interpersonal realms. When couples seek in vitro fertilisation (IVF) treatment, they further suffer from the difficulties of the treatment and the uncertainty of its outcome. The aim of this study was to develop a preliminary conceptual framework for couples undergoing IVF treatment to give health professionals a better understanding of the experiences of such couples, and to guide the development of an intervention. The process of identifying frameworks adopted in intervention studies confirmed that there is no established framework for infertile couples undergoing IVF treatment. A skeletal framework identified from previous studies provides an internal structure for the proposed framework for couples undergoing IVF treatment, filled out with concepts drawn from a concept analysis and a qualitative study, knitting the structure together. This preliminary framework is the Endurance with Partnership Conceptual Framework (P-EPCF). It consists of four domains: the impacts of infertility and stressors, dyadic mediators, dyadic moderators and dyadic outcomes. According to the P-EPCF, the impacts of infertility and IVF treatment can be mediated by the couples' partnership and dyadic coping. Improvements in the psychological well-being and marital functioning of IVF couples can then be expected. The P-EPCF would be potentially valuable in guiding the development of a complex, couple-based intervention, which could focus on enhancing the partnership of couples and their coping strategies.

77 FR 57197 - Proposed Collection; Comment Request for Form 1099-CAP

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-17

... 1099-CAP AGENCY: Internal Revenue Service (IRS), Treasury. ACTION: Notice and request for comments... Form 1099-CAP, Changes in Corporate Control and Capital Structure. DATES: Written comments should be... Structure. OMB Number: 1545-1814. Form Number: 1099-CAP. Abstract: Any corporation that undergoes...

Dermatological Manifestations in Patients Undergoing In Vitro Fertilisation: A Prospective Study.

PubMed

Sood, Aradhana; Sahu, Suvash; Karunakaran, Sandeep; Joshi, Rajneesh K; Raman, Deep Kumar

Changing sociodemographic patterns with an increase in the age of childbirth have affected fertility rates worldwide. With advancing reproductive medicine, assisted reproductive techniques (ARTs) are becoming common. While dermatological manifestations in normal pregnancies have been well documented, there is a paucity of data regarding cutaneous manifestations in patients undergoing ART. The objectives of our study were to estimate the incidence and types of dermatological manifestations in patients undergoing in vitro fertilisation (IVF) and to study their associations with age, type of infertility, and outcome of the procedure. A prospective cohort of 200 patients undergoing IVF in a tertiary care centre was observed for occurrence of any dermatological manifestations from initiation of the IVF protocol to the outcome of the procedure at 3 weeks after embryo transfer. Dermatological manifestations were seen in 27% of the study group, with urticaria being the most common cutaneous finding seen in 13.5%, followed by acneform eruptions (3%). Twenty-six (96.3%) of patients who manifested with urticaria were on progesterone. No statistically significant association was found between the occurrence of dermatological manifestations and the outcome of IVF, type of infertility, history of ART, and ovum donation in our study. Association between the age of the patient and the outcome of IVF cycle was statistically significant. Dermatological manifestations are seen in almost one-quarter of patients undergoing IVF, with progesterone-induced urticaria being the most common. Occurrence of cutaneous manifestations has no significant association with the outcome of IVF.

Structure of the protein phosphatase 2A holoenzyme.

PubMed

Xu, Yanhui; Xing, Yongna; Chen, Yu; Chao, Yang; Lin, Zheng; Fan, Eugene; Yu, Jong W; Strack, Stefan; Jeffrey, Philip D; Shi, Yigong

2006-12-15

Protein Phosphatase 2A (PP2A) plays an essential role in many aspects of cellular physiology. The PP2A holoenzyme consists of a heterodimeric core enzyme, which comprises a scaffolding subunit and a catalytic subunit, and a variable regulatory subunit. Here we report the crystal structure of the heterotrimeric PP2A holoenzyme involving the regulatory subunit B'/B56/PR61. Surprisingly, the B'/PR61 subunit has a HEAT-like (huntingtin-elongation-A subunit-TOR-like) repeat structure, similar to that of the scaffolding subunit. The regulatory B'/B56/PR61 subunit simultaneously interacts with the catalytic subunit as well as the conserved ridge of the scaffolding subunit. The carboxyterminus of the catalytic subunit recognizes a surface groove at the interface between the B'/B56/PR61 subunit and the scaffolding subunit. Compared to the scaffolding subunit in the PP2A core enzyme, formation of the holoenzyme forces the scaffolding subunit to undergo pronounced conformational rearrangements. This structure reveals significant ramifications for understanding the function and regulation of PP2A.

Development of Metallic Sensory Alloys

NASA Technical Reports Server (NTRS)

Wallace Terryl A.; Newman, John A.; Horne, Michael R.; Messick, Peter L.

2010-01-01

Existing nondestructive evaluation (NDE) technologies are inherently limited by the physical response of the structural material being inspected and are therefore not generally effective at the identification of small discontinuities, making the detection of incipient damage extremely difficult. One innovative solution to this problem is to enhance or complement the NDE signature of structural materials to dramatically improve the ability of existing NDE tools to detect damage. To address this need, a multifunctional metallic material has been developed that can be used in structural applications. The material is processed to contain second phase sensory particles that significantly improve the NDE response, enhancing the ability of conventional NDE techniques to detect incipient damage both during and after flight. Ferromagnetic shape-memory alloys (FSMAs) are an ideal material for these sensory particles as they undergo a uniform and repeatable change in both magnetic properties and crystallographic structure (martensitic transformation) when subjected to strain and/or temperature changes which can be detected using conventional NDE techniques. In this study, the use of a ferromagnetic shape memory alloy (FSMA) as the sensory particles was investigated.

Structural complexity of simple Fe 2O 3 at high pressures and temperatures

DOE PAGES

Bykova, Elena; Dubrovinsky, L.; Dubrovinskaia, N.; ...

2016-02-11

Although chemically very simple, Fe 2O 3 is known to undergo a series of enigmatic structural, electronic and magnetic transformations at high pressures and high temperatures. So far, these transformations have neither been correctly described nor understood because of the lack of structural data. Here we report a systematic investigation of the behaviour of Fe 2O 3 at pressures over 100 GPa and temperatures above 2,500 K employing single crystal X-ray diffraction and synchrotron Mössbauer source spectroscopy. Crystal chemical analysis of structures presented here and known Fe(II, III) oxides shows their fundamental relationships and that they can be described bymore » the homologous series nFeO·mFe 2O 3. Decomposition of Fe 2O 3 and Fe 3O 4 observed at pressures above 60 GPa and temperatures of 2,000 K leads to crystallization of unusual Fe 5O 7 and Fe 25O 32 phases with release of oxygen. Lastly, our findings suggest that mixed-valence iron oxides may play a significant role in oxygen cycling between earth reservoirs.« less

Drastic stabilization of parallel DNA hybridizations by a polylysine comb-type copolymer with hydrophilic graft chain.

PubMed

Miyoshi, Daisuke; Ueda, Yu-Mi; Shimada, Naohiko; Nakano, Shu-Ichi; Sugimoto, Naoki; Maruyama, Atsushi

2014-09-01

Electrostatic interactions play a major role in protein-DNA interactions. As a model system of a cationic protein, herein we focused on a comb-type copolymer of a polycation backbone and dextran side chains, poly(L-lysine)-graft-dextran (PLL-g-Dex), which has been reported to form soluble interpolyelectrolyte complexes with DNA strands. We investigated the effects of PLL-g-Dex on the conformation and thermodynamics of DNA oligonucleotides forming various secondary structures. Thermodynamic analysis of the DNA structures showed that the parallel conformations involved in both DNA duplexes and triplexes were significantly and specifically stabilized by PLL-g-Dex. On the basis of thermodynamic parameters, it was further possible to design DNA switches that undergo structural transition responding to PLL-g-Dex from an antiparallel duplex to a parallel triplex even with mismatches in the third strand hybridization. These results suggest that polycationic molecules are able to induce structural polymorphism of DNA oligonucleotides, because of the conformation-selective stabilization effects. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Solution Structure, Binding Properties, and Dynamics of the Bacterial Siderophore-binding Protein FepB*

PubMed Central

Chu, Byron C. H.; Otten, Renee; Krewulak, Karla D.; Mulder, Frans A. A.; Vogel, Hans J.

2014-01-01

The periplasmic binding protein (PBP) FepB plays a key role in transporting the catecholate siderophore ferric enterobactin from the outer to the inner membrane in Gram-negative bacteria. The solution structures of the 34-kDa apo- and holo-FepB from Escherichia coli, solved by NMR, represent the first solution structures determined for the type III class of PBPs. Unlike type I and II PBPs, which undergo large “Venus flytrap” conformational changes upon ligand binding, both forms of FepB maintain similar overall folds; however, binding of the ligand is accompanied by significant loop movements. Reverse methyl cross-saturation experiments corroborated chemical shift perturbation results and uniquely defined the binding pocket for gallium enterobactin (GaEnt). NMR relaxation experiments indicated that a flexible loop (residues 225–250) adopted a more rigid and extended conformation upon ligand binding, which positioned residues for optimal interactions with the ligand and the cytoplasmic membrane ABC transporter (FepCD), respectively. In conclusion, this work highlights the pivotal role that structural dynamics plays in ligand binding and transporter interactions in type III PBPs. PMID:25173704

Management patterns of medicare patients undergoing treatment for upper urinary tract calculi.

PubMed

Matlaga, Brian R; Meckley, Lisa M; Kim, Micheline; Byrne, Thomas W

2014-06-01

We conducted this study to identify differences in the re-treatment rates and ancillary procedures for the two most commonly utilized stone treatment procedures in the Medicare population: ureteroscopy (URS) and shock wave lithotripsy (SWL). A retrospective claims analysis of the Medicare standard analytical file 5% sample was conducted to identify patients with a new diagnosis of urolithiasis undergoing treatment with URS or SWL from 2009-2010. Outcomes evaluated: (1) repeat stone removal procedures within 120 days post index procedure, (2) stent placement procedures on the index date, 30 days prior to and 120 days post index date, and (3) use of general anesthesia. We identified 3885 eligible patients, of which 2165 (56%) underwent SWL and 1720 (44%) underwent URS. Overall, SWL patients were 1.73 times more likely to undergo at least one repeat procedure than URS patients, and twice as likely to require multiple re-treatments compared to URS. Among those with ureteral stones, SWL patients were 2.27 times more likely to undergo repeat procedures. The difference was not statistically significant in renal stone patients. Overall, SWL patients were 1.41 times more likely than URS patients to have a stent placed prior to index procedure, and 1.33 times more likely to have a stent placed subsequent to the index procedure. The majority of URS patients (77.8%) had a stent placed at the time of index procedure. There was no significant difference in anesthetic approaches between SWL and URS. Patients undergoing SWL are significantly more likely to require re-treatments than URS patients. SWL patients are also significantly more likely to require ureteral stent placement as a separate event. SWL and URS patients have similar rates of general anesthesia.

The economic implications of a multimodal analgesic regimen for patients undergoing major orthopedic surgery: a comparative study of direct costs.

PubMed

Duncan, Christopher M; Hall Long, Kirsten; Warner, David O; Hebl, James R

2009-01-01

Total knee and total hip arthoplasty (THA) are 2 of the most common surgical procedures performed in the United States and represent the greatest single Medicare procedural expenditure. This study was designed to evaluate the economic impact of implementing a multimodal analgesic regimen (Total Joint Regional Anesthesia [TJRA] Clinical Pathway) on the estimated direct medical costs of patients undergoing lower extremity joint replacement surgery. An economic cost comparison was performed on Mayo Clinic patients (n = 100) undergoing traditional total knee or total hip arthroplasty using the TJRA Clinical Pathway. Study patients were matched 1:1 with historical controls undergoing similar procedures using traditional anesthetic (non-TJRA) techniques. Matching criteria included age, sex, surgeon, type of procedure, and American Society of Anesthesiologists (ASA) physical status (PS) classification. Hospital-based direct costs were collected for each patient and analyzed in standardized inflation-adjusted constant dollars using cost-to-charge ratios, wage indexes, and physician services valued using Medicare reimbursement rates. The estimated mean direct hospital costs were compared between groups, and a subgroup analysis was performed based on ASA PS classification. The estimated mean direct hospital costs were significantly reduced among TJRA patients when compared with controls (cost difference, 1999 dollars; 95% confidence interval, 584-3231 dollars; P = 0.0004). A significant reduction in hospital-based (Medicare Part A) costs accounted for the majority of the total cost savings. Use of a comprehensive, multimodal analgesic regimen (TJRA Clinical Pathway) in patients undergoing lower extremity joint replacement surgery provides a significant reduction in the estimated total direct medical costs. The reduction in mean cost is primarily associated with lower hospital-based (Medicare Part A) costs, with the greatest overall cost difference appearing among patients with significant comorbidities (ASA PS III-IV patients).

Transection Speed and Impact on Perioperative Inflammatory Response - A Randomized Controlled Trial Comparing Stapler Hepatectomy and CUSA Resection.

PubMed

Schwarz, Christoph; Klaus, Daniel A; Tudor, Bianca; Fleischmann, Edith; Wekerle, Thomas; Roth, Georg; Bodingbauer, Martin; Kaczirek, Klaus

2015-01-01

Parenchymal transection represents a crucial step during liver surgery and many different techniques have been described so far. Stapler resection is supposed to be faster than CUSA resection. However, whether speed impacts on the inflammatory response in patients undergoing liver resection (LR) remains unclear. This is a randomized controlled trial including 40 patients undergoing anatomical LR. Primary endpoint was transection speed (cm2/min). Secondary endpoints included the perioperative change of pro- and anti-inflammatory cytokines, overall surgery duration, length of hospital stay, morbidity and mortality. Mean transection speed was significantly higher in patients undergoing stapler hepatectomy compared to CUSA resection (CUSA: 1 (0.4) cm2/min vs. Stapler: 10.8 (6.1) cm2/min; p<0.0001). Analyzing the impact of surgery duration on inflammatory response revealed a significant correlation between IL-6 levels measured at the end of surgery and the overall length of surgery (p<0.0001, r = 0.6188). Patients undergoing CUSA LR had significantly higher increase of interleukin-6 (IL-6) after parenchymal transection compared to patients with stapler hepatectomy in the portal and hepatic veins, respectively (p = 0.028; p = 0.044). C-reactive protein levels on the first post-operative day were significantly lower in the stapler cohort (p = 0.010). There was a trend towards a reduced overall surgery time in patients with stapler LR, especially in the subgroup of patients undergoing minor hepatectomies (p = 0.020). Liver resection using staplers is fast, safe and suggests a diminished inflammatory response probably due to a decreased parenchymal transection time. ClinicalTrials.gov NCT01785212.

Transection Speed and Impact on Perioperative Inflammatory Response – A Randomized Controlled Trial Comparing Stapler Hepatectomy and CUSA Resection

PubMed Central

Schwarz, Christoph; Klaus, Daniel A.; Tudor, Bianca; Fleischmann, Edith; Wekerle, Thomas; Roth, Georg; Bodingbauer, Martin; Kaczirek, Klaus

2015-01-01

Background Parenchymal transection represents a crucial step during liver surgery and many different techniques have been described so far. Stapler resection is supposed to be faster than CUSA resection. However, whether speed impacts on the inflammatory response in patients undergoing liver resection (LR) remains unclear. Materials and Methods This is a randomized controlled trial including 40 patients undergoing anatomical LR. Primary endpoint was transection speed (cm2/min). Secondary endpoints included the perioperative change of pro- and anti-inflammatory cytokines, overall surgery duration, length of hospital stay, morbidity and mortality. Results Mean transection speed was significantly higher in patients undergoing stapler hepatectomy compared to CUSA resection (CUSA: 1 (0.4) cm2/min vs. Stapler: 10.8 (6.1) cm2/min; p<0.0001). Analyzing the impact of surgery duration on inflammatory response revealed a significant correlation between IL-6 levels measured at the end of surgery and the overall length of surgery (p<0.0001, r = 0.6188). Patients undergoing CUSA LR had significantly higher increase of interleukin-6 (IL-6) after parenchymal transection compared to patients with stapler hepatectomy in the portal and hepatic veins, respectively (p = 0.028; p = 0.044). C-reactive protein levels on the first post-operative day were significantly lower in the stapler cohort (p = 0.010). There was a trend towards a reduced overall surgery time in patients with stapler LR, especially in the subgroup of patients undergoing minor hepatectomies (p = 0.020). Conclusions Liver resection using staplers is fast, safe and suggests a diminished inflammatory response probably due to a decreased parenchymal transection time. Trial Registration ClinicalTrials.gov NCT01785212 PMID:26452162

[Clinical outcomes and economic analysis of two ovulation induction protocols in patients undergoing repeated IVF/ICSI cycles].

PubMed

Chen, Xiao; Geng, Ling; Li, Hong

2014-04-01

To compare the clinical outcomes and cost-effectiveness of luteal phase down-regulation with gonadotrophin-releasing hormone (GnRH) agonist protocol and GnRH antagonist protocol in patients undergoing repeated in vitro fertilization and intracytoplasmic sperm injection (IVF-ICSI) cycles. A retrospective analysis of clinical outcomes and costs was conducted among 198 patients undergoing repeated IVF-ICSI cycles, including 109 receiving luteal phase down-regulation with GnRH agonist protocol (group A) and 89 receiving GnRH antagonist protocol (group B). The numbers of oocytes retrieved and good embryos, clinical pregnancy rate, abortion rate, the live birth rate, mean total cost, and the cost-effective ratio were compared between the two groups. In patients undergoing repeated IVF-ICSI cycles, the two protocols produced no significant differences in the number of good embryos, clinical pregnancy rate, abortion rate, or twin pregnancy rate. Compared with group B, group A had better clinical outcomes though this difference was not statistically significant. The number of retrieved oocytes was significantly greater and live birth rate significantly higher in group A than in group B (9.13=4.98 vs 7.11=4.74, and 20.2% vs 9.0%, respectively). Compared with group B, group A had higher mean total cost per cycle but lower costs for each oocyte retrieved (2729.11 vs 3038.60 RMB yuan), each good embryo (8867.19 vs 9644.85 RMB yuan), each clinical pregnancy (77598.06 vs 96139.85 RMB yuan). For patients undergoing repeated IVF/ICSI cycle, luteal phase down-regulation with GnRH agonist protocol produces good clinical outcomes with also good cost-effectiveness in spite an unsatisfactory ovarian reserve.

Patella Fractures Prior to Total Knee Arthroplasty: Worse Outcomes but Equivalent Survivorship.

PubMed

Houdek, Matthew T; Shannon, Steven F; Watts, Chad D; Wagner, Eric R; Sems, Stephen A; Sierra, Rafael J

2015-12-01

Distal femur and/or tibial plateau fractures adversely affect outcomes of TKA; however it is unknown if a previous patella fracture affects outcome. We reviewed 113 patients undergoing TKA with a previous patella fracture from 1990 to 2012. Component survival was compared to 19,641 patients undergoing TKA for osteoarthritis during the same period. The 15-year implant survivals following a previous patella fracture was 86%. There was no difference in implant survival compared to patients undergoing TKA for OA (P=0.31). Knee society scores significantly improved following TKA; however patients with a fracture had complications related to knee flexion. Patients undergoing primary TKA following a patella fracture have similar overall revision free survival compared to those undergoing TKA for OA at 15-years. Copyright © 2015 Elsevier Inc. All rights reserved.

An ultraviolet crosslink in the hammerhead ribozyme dependent on 2-thiocytidine or 4-thiouridine substitution.

PubMed Central

Wang, L; Ruffner, D E

1997-01-01

The hammerhead domain is one of the smallest known ribozymes. Like other ribozymes it catalyzes site-specific cleavage of a phosphodiester bond. The hammerhead ribozyme has been the subject of a vast number of biochemical and structural studies aimed at determining the structure and mechanism of cleavage. Recently crystallographic analysis has produced a structure for the hammerhead. As the hammerhead is capable of undergoing cleavage within the crystal, it would appear that the crystal structure is representative of the catalytically active solution structure. However, the crystal structure conflicts with much of the biochemical data and reveals a catalytic metal ion binding site expected to be of very low affinity. Clearly, additional studies are needed to reconcile the discrepancies and provide a clear understanding of the structure and mechanism of the hammerhead ribozyme. Here we demonstrate that a unique crosslink can be induced in the hammerhead with 2-thiocytidine or 4-thiouridine substitution at different locations within the conserved core. Generation of the same crosslink with different modifications at different positions suggests that the structure trapped by the crosslink may be relevant to the catalytically active solution structure of the hammerhead ribozyme. As this crosslink appears to be incompatible with the crystal structure, this provides yet another indication that the active solution and crystal structures may differ significantly. PMID:9336468

Investigation of the Enzymes Involved in Lantibiotic Biosynthesis: Lacticin 481 and Haloduracin

ERIC Educational Resources Information Center

Ihnken, Leigh Anne Furgerson

2009-01-01

Lantibiotics are cyclic peptides that exhibit a range of biological properties, including antimicrobial activity. They are ribosomally-synthesized as linear precursor peptides that consist of two regions, an N-terminal leader peptide and a C-terminal propeptide (or structural) region. The structural region undergoes extensive enzyme-catalyzed…

Long-term cardiovascular changes following creation of arteriovenous fistula in patients with end stage renal disease.

PubMed

Reddy, Yogesh N V; Obokata, Masaru; Dean, Patrick G; Melenovsky, Vojtech; Nath, Karl A; Borlaug, Barry A

2017-06-21

Short-term studies have reported left ventricular (LV) dilatation following surgical creation of arteriovenous fistulas (AVF) or arteriovenous grafts (AVGs), but chronic cardiac structural and functional changes have not been examined or related to clinical outcomes following AVF/AVG. We sought to characterize the long-term changes in cardiac structure and function in patients undergoing shunt creation for haemodialysis. A retrospective analysis was performed of patients undergoing echocardiography before and after surgical AVF/AVG creation for the initiation of haemodialysis. 137 patients underwent echocardiographic examinations prior to AVF and 2.6 years (median) after AVF creation. Following AVF and dialysis initiation, there were reductions in blood pressure, body weight and estimated plasma volume coupled with modest reverse LV remodelling. In contrast, AVF/AVG creation was associated with significant right ventricular (RV) dilatation and deterioration in RV function. Incident heart failure (HF) developed in 43% of patients in tandem with greater RV remodeling. The development of RV dilation following surgical AVF/AVG was independently associated with increased risk of death [HR 3.9, 95% CI (1.7-9.2), P = 0.001]. In long-term follow-up, RV remodelling and dysfunction develop following AVF/AVG creation and dialysis initiation, despite improved control of LV pressure load through dialysis. Deleterious effects on right heart structure and function are coupled with development of incident HF and increased risk of death. Further study is required to identify patients at greatest risk for detrimental AVF/AVG changes who may benefit from alternate forms of dialysis or potentially ligation of existing AVF. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions, please email: journals.permissions@oup.com.

Anatomic relationship between left coronary artery and left atrium in patients undergoing atrial fibrillation ablation.

PubMed

Anselmino, Matteo; Torri, Federica; Ferraris, Federico; Calò, Leonardo; Castagno, Davide; Gili, Sebastiano; Rovera, Chiara; Giustetto, Carla; Gaita, Fiorenzo

2017-07-01

Atrial fibrillation transcatheter ablation (TCA) is, within available atrial fibrillation rhythm control strategies, one of the most effective. To potentially improve ablation outcome in case of recurrent atrial fibrillation after a first procedure or in presence of structural myocardial disease, isolation of the pulmonary veins may be associated with extensive lesions within the left atrium. To avoid rare, but potentially life-threatening, complications, thorough knowledge and assessment of left atrium anatomy and its relation to structures in close proximity are, therefore, mandatory. Aim of the present study is to describe, by cardiac computed tomography, the anatomic relationship between aortic root, left coronary artery and left atrium in patients undergoing atrial fibrillation TCA. The cardiac computed tomography scan of 21 patients affected by atrial fibrillation was elaborated to segment left atrium, aortic root and left coronary artery from the surrounding structures and the following distances measured: left atrium and aortic root; left atrium roof and aortic root; left main coronary artery and left atrium; circumflex artery and left atrium appendage; and circumflex artery and mitral valve annulus. Above all, the median distance between left atrium and aortic root (1.9, 1.5-2.1 mm), and between circumflex artery and left atrium appendage ostium (3.0, 2.1-3.4 mm) were minimal (≤3 mm). None of measured distances significantly varied between patients presenting paroxysmal versus persistent atrial fibrillation. The anatomic relationship between left atrium and coronary arteries is extremely relevant when performing atrial fibrillation TCA by extensive lesions. Therefore, at least in the latter case, preablation imaging should be recommended to avoid rare, but potentially life-threatening, complications with the aim of an as well tolerated as possible procedure.

Finite element based contact analysis of radio frequency MEMs switch membrane surfaces

NASA Astrophysics Data System (ADS)

Liu, Jin-Ya; Chalivendra, Vijaya; Huang, Wenzhen

2017-10-01

Finite element simulations were performed to determine the contact behavior of radio frequency (RF) micro-electro-mechanical (MEM) switch contact surfaces under monotonic and cyclic loading conditions. Atomic force microscopy (AFM) was used to capture the topography of RF-MEM switch membranes and later they were analyzed for multi-scale regular as well as fractal structures. Frictionless, non-adhesive contact 3D finite element analysis was carried out at different length scales to investigate the contact behavior of the regular-fractal surface using an elasto-plastic material model. Dominant micro-scale regular patterns were found to significantly change the contact behavior. Contact areas mainly cluster around the regular pattern. The contribution from the fractal structure is not significant. Under cyclic loading conditions, plastic deformation in the 1st loading/unloading cycle smooth the surface. The subsequent repetitive loading/unloading cycles undergo elastic contact without changing the morphology of the contacting surfaces. The work is expected to shed light on the quality of the switch surface contact as well as the optimum design of RF MEM switch surfaces.

The Grasshopper Neuroblast Culture Technique and its Value in Radiobiological Studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carlson, J. Gordon

1961-11-01

A technique is described for the culture of grasshopper neuroblasts in which the neuroblast undergoes successive divisions at a relatively uniform rate through a total of 6 mitotic cycles over a period of 5 to 6 days at 26 deg C. Even after mitosis ceases, most of the embryonic cells live and undergo differentiation. Results are summarized from studies on the effects of different kinds of radiation on mitosis and on structure and behavior of various parts of the dividing cell. (C.H.)

Acoustic emission characterization of steel fibre reinforced concrete during bending

NASA Astrophysics Data System (ADS)

Aggelis, D. G.; Soulioti, D. V.; Sapouridis, N.; Barkoula, N. M.; Paipetis, A. S.; Matikas, T. E.

2010-04-01

The acoustic emission (AE) behaviour of steel fibre reinforced concrete is studied in this paper. The experiments were conducted in four-point bending with concurrent monitoring of AE signals. The sensors used, were of broadband response in order to capture a wide range of fracturing phenomena. The results indicate that AE parameters undergo significant changes much earlier than the final fracture of the specimens, even if the AE hit rate seems approximately constant. Specifically, the Ib-value which takes into account the amplitude distribution of the recent AE hits decreases when the load reaches about 60-70 % of its maximum value. Additionally, the average frequency of the signals decreases abruptly when a fracture incident occurs, indicating that matrix cracking events produce higher frequencies than fibre pull-out events. It is concluded that proper study of AE parameters enables the characterization of structural health of large structures in cases where remote monitoring is applied.

Molecular Characteristics and Biological Functions of Surface-Active and Surfactant Proteins.

PubMed

Sunde, Margaret; Pham, Chi L L; Kwan, Ann H

2017-06-20

Many critical biological processes take place at hydrophobic:hydrophilic interfaces, and a wide range of organisms produce surface-active proteins and peptides that reduce surface and interfacial tension and mediate growth and development at these boundaries. Microorganisms produce both small lipid-associated peptides and amphipathic proteins that allow growth across water:air boundaries, attachment to surfaces, predation, and improved bioavailability of hydrophobic substrates. Higher-order organisms produce surface-active proteins with a wide variety of functions, including the provision of protective foam environments for vulnerable reproductive stages, evaporative cooling, and gas exchange across airway membranes. In general, the biological functions supported by these diverse polypeptides require them to have an amphipathic nature, and this is achieved by a diverse range of molecular structures, with some proteins undergoing significant conformational change or intermolecular association to generate the structures that are surface active.

6th International Conference on Nanomaterials by Severe Plastic Deformation (NanoSPD6)

NASA Astrophysics Data System (ADS)

2014-08-01

''NanoSPD'' means Nano-material by Severe Plastic Deformation (SPD), which is an efficient way to obtain bulk nano-structured materials. During SPD, the microstructure of the material is transformed into a very fine structure consisting of ultra fine grains (UFG) approaching even the nano-scale. SPD is different from classical large strain forming processes in two aspects: 1. The sample undergoes extremely large strains without significant change in its dimensions, 2. In most SPD processes high hydrostatic stress is applied which makes it possible to deform difficult-to-form materials. This conference is part of a series of conferences taking place every third year; the history of NanoSPD conferences began in 1999 in Moscow (Russia), followed by Vienna in 2002 (Austria), Fukuoka in 2005 (Japan), Goslar in 2008 (Germany), Nanjing in 2011 (China), and Metz in 2014 (France). The preface continues in the pdf.

Tracking the Remodeling of SNOMED CT's Bacterial Infectious Diseases.

PubMed

Ochs, Christopher; Case, James T; Perl, Yehoshua

2016-01-01

SNOMED CT's content undergoes many changes from one release to the next. Over the last year SNOMED CT's Bacterial infectious disease subhierarchy has undergone significant editing to bring consistent modeling to its concepts. In this paper we analyze the stated and inferred structural modifications that affected the Bacterial infectious disease subhierarchy between the Jan 2015 and Jan 2016 SNOMED CT releases using a two-phased approach. First, we introduce a methodology for creating a human readable list of changes. Next, we utilize partial-area taxonomies, which are compact summaries of SNOMED CT's content and structure, to identify the "big picture" changes that occurred in the subhierarchy. We illustrate how partial-area taxonomies can be used to help identify groups of concepts that were affected by these editing operations and the nature of these changes. Modeling issues identified using our two-phase methodology are discussed.

Static analysis of C-shape SMA middle ear prosthesis

NASA Astrophysics Data System (ADS)

Latalski, Jarosław; Rusinek, Rafał

2017-08-01

Shape memory alloys are a family of metals with the ability to change specimen shape depending on their temperature. This unique property is useful in many areas of mechanical and biomechanical engineering. A new half-ring middle ear prosthesis design made of a shape memory alloy, that is undergoing initial clinical tests, is investigated in this research paper. The analytical model of the studied structure made of nonlinear constitutive material is solved to identify the temperature-dependent stiffness characteristics of the proposed design on the basis of the Crotti-Engesser theorem. The final integral expression for the element deflection is highly complex, thus the solution has to be computed numerically. The final results show the proposed shape memory C-shape element to behave linearly in the analysed range of loadings and temperatures. This is an important observation that significantly simplifies the analysis of the prototype structure and opens wide perspectives for further possible applications of shape memory alloys.

How to Make a Heart Valve: From Embryonic Development to Bioengineering of Living Valve Substitutes

PubMed Central

MacGrogan, Donal; Luxán, Guillermo; Driessen-Mol, Anita; Bouten, Carlijn; Baaijens, Frank; de la Pompa, José Luis

2014-01-01

Cardiac valve disease is a significant cause of ill health and death worldwide, and valve replacement remains one of the most common cardiac interventions in high-income economies. Despite major advances in surgical treatment, long-term therapy remains inadequate because none of the current valve substitutes have the potential for remodeling, regeneration, and growth of native structures. Valve development is coordinated by a complex interplay of signaling pathways and environmental cues that cause disease when perturbed. Cardiac valves develop from endocardial cushions that become populated by valve precursor mesenchyme formed by an epithelial–mesenchymal transition (EMT). The mesenchymal precursors, subsequently, undergo directed growth, characterized by cellular compartmentalization and layering of a structured extracellular matrix (ECM). Knowledge gained from research into the development of cardiac valves is driving exploration into valve biomechanics and tissue engineering directed at creating novel valve substitutes endowed with native form and function. PMID:25368013

Loop-driven conformational transition between the alternative and collapsed form of prethrombin-2: targeted molecular dynamics study.

PubMed

Wu, Sangwook

2017-01-01

Two distinct crystal structures of prethrombin-2, the alternative and collapsed forms, are elucidated by X-ray crystallogrphy. We analyzed the conformational transition from the alternative to the collapsed form employing targeted molecular dynamics (TMD) simulation. Despite small RMSD difference in the two X-ray crystal structures, some hydrophobic residues (W60d, W148, W215, and F227) show a significant difference between the two conformations. TMD simulation shows that the four hydrophobic residues undergo concerted movement from dimer to trimer transition via tetramer state in the conformational change from the alternative to the collapsed form. We reveal that the concerted movement of the four hydrophobic residues is controlled by movement of specific loop regions behind. In this paper, we propose a sequential scenario for the conformational transition from the alternative form to the collapsed form, which is partially supported by the mutant W148A simulation.

Cell-free DNA and telomere length among women undergoing in vitro fertilization treatment.

PubMed

Czamanski-Cohen, J; Sarid, O; Cwikel, J; Douvdevani, A; Levitas, E; Lunenfeld, E; Har-Vardi, I

2015-11-01

The current research is aimed at finding potential non-invasive bio-markers that will help us learn more about the mechanisms at play in failed assisted reproduction treatment. This exploratory pilot study examined the relationship between cell-free DNA (CFD) in plasma and telomere length in lymphocytes among women undergoing in vitro fertilization (IVF) and compared telomere length and CFD levels to a healthy control group. Blood of 20 women undergoing IVF was collected at three time points during the IVF cycle. We assessed the relationship between CFD and telomere length as well as controlling for morning cortisol levels. We also collected blood of 10 healthy controls at two time points (luteal and follicular phases of the menstrual cycle) and compared mean telomere length, CFD, and cortisol levels between the IVF patients and healthy controls. The results revealed an inverse relationship between CFD levels and telomere lengths at several time points that remained significant even after controlling for cortisol levels. Women undergoing IVF had statistically significant higher levels of CFD and shorter telomeres compared to healthy controls. The relationship between telomere length and CFD should be further explored in larger studies in order to uncover potential mechanisms that cause both shortened telomere length and elevated CFD in women undergoing IVF.

A prospective study of postoperative symptoms in sinonasal quality-of-life following endoscopic skull-base surgery: dissociations based on specific symptoms.

PubMed

Bedrosian, Jeffrey C; McCoul, Edward D; Raithatha, Roheen; Akselrod, Olga A; Anand, Vijay K; Schwartz, Theodore H

2013-08-01

Endoscopic skull-base surgery (ESBS) is a minimal access approach to cranial base pathology; however, it significantly disrupts the intranasal mucosa and intranasal structures, the long-term effects of which are still being studied. We prospectively assessed postoperative changes in sinonasal QOL symptoms following ESBS. Eighty-five patients were prospectively assessed with the Anterior Skull Base Questionnaire (ASBQ), a validated QOL instrument, preoperatively and up to 1 year postoperatively at each subsequent office visit. A subset of these data was analyzed to assess the effect of endoscopic pituitary surgery on postoperative taste, smell, appetite, nasal secretions, and vision. ESBS patients were divided into 2 cohorts: those undergoing pituitary adenoma surgery and those undergoing ESBS for all other pathologies. Preoperative smell (3.11 vs 3.76, p = 0.03) and taste (3.04 vs 3.69, p = 0.03) were significantly lower in the nonpituitary group. Within the pituitary group both taste (3.69 vs 2.95, p = 0.03) and smell (3.76 vs 2.61, p ≤ 0.001) were significantly decreased by 6 weeks postoperatively. However, by 12 months both taste and smell scores returned to baseline. Vision scores improved by 3 weeks postoperatively with durable results at 1 year (2.80 vs 3.33, p = 0.04 vs 3.59, p = 0.03, respectively). Within the nonpituitary group, smell was decreased at 3 weeks, but was not significantly changed at any other time points. Our study indicates a dissociation between the nasal and visual QOL after ESBS. While nasal QOL transiently decreases, visual QOL progressively improves. These data should not be lumped together for the purposes of statistical analysis. © 2013 ARS-AAOA, LLC.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chesny, D. L.; Oluseyi, H. M.; Orange, N. B.

We report on the identification of dynamic flaring non-potential structures on quiet Sun (QS) supergranular network scales. Data from the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory allow for the high spatial and temporal resolution of this diverse class of compact structures. The rapidly evolving non-potential events presented here, with lifetimes <10 minutes, are on the order of 10″ in length. Thus, they contrast significantly with well-known active region (AR) non-potential structures such as high-temperature X-ray and EUV sigmoids (>100″) and micro-sigmoids (>10″) with lifetimes on the order of hours to days. The photospheric magnetic field environment derivedmore » from the Helioseismic and Magnetic Imager shows a lack of evidence for these flaring non-potential fields being associated with significant concentrations of bipolar magnetic elements. Of much interest to our events is the possibility of establishing them as precursor signatures of eruptive dynamics, similar to notions for AR sigmoids and micro-sigmoids, but associated with uneventful magnetic network regions. We suggest that the mixed network flux of QS-like magnetic environments, though unresolved, can provide sufficient free magnetic energy for flaring non-potential plasma structuring. The appearance of non-potential magnetic fields could be a fundamental process leading to self-organized criticality in the QS-like supergranular network and contribute to coronal heating, as these events undergo rapid helicial and vortical relaxations.« less

Postaragonite phases of CaCO3 at lower mantle pressures

NASA Astrophysics Data System (ADS)

Smith, Dean; Lawler, Keith V.; Martinez-Canales, Miguel; Daykin, Austin W.; Fussell, Zachary; Smith, G. Alexander; Childs, Christian; Smith, Jesse S.; Pickard, Chris J.; Salamat, Ashkan

2018-01-01

The stability, structure, and properties of carbonate minerals at lower mantle conditions have significant impact on our understanding of the global carbon cycle and the composition of the interior of the Earth. In recent years there has been significant interest in the behavior of carbonates at lower mantle conditions, specifically in their carbon hybridization, which has relevance for the storage of carbon within the deep mantle. Using high-pressure synchrotron x-ray diffraction in a diamond anvil cell coupled with direct laser heating of CaCO3 using a CO2 laser, we identify a crystalline phase of the material above 40 GPa—corresponding to a lower mantle depth of around 1000 km—which has first been predicted by ab initio structure predictions. The observed s p2 carbon hybridized species at 40 GPa is monoclinic with P 21/c symmetry and is stable up to 50 GPa, above which it transforms into a structure which cannot be indexed by existing known phases. A combination of ab initio random structure search (AIRSS) and quasiharmonic approximation (QHA) calculations are used to re-explore the relative phase stabilities of the rich phase diagram of CaCO3. Nudged elastic band (NEB) calculations are used to investigate the reaction mechanisms between relevant crystal phases of CaCO3 and we postulate that the mineral is capable of undergoing s p2-s p3 hybridization change purely in the P 21/c structure—forgoing the accepted postaragonite P m m n structure.

Embryo yield after in vitro fertilization in women undergoing embryo banking for fertility preservation before chemotherapy.

PubMed

Robertson, Audra D; Missmer, Stacey A; Ginsburg, Elizabeth S

2011-02-01

To evaluate embryo yield after IVF in patients undergoing embryo banking before chemotherapy. A retrospective cohort study. Hospital-based academic medical center. Thirty-eight women diagnosed with cancer or autoimmune disease presenting for IVF cycles, with or without intracytoplasmic sperm injection (ICSI), for embryo cryopreservation before any therapy were compared with 921 presumably fertile women undergoing IVF for male factor infertility from January 2001 through October 2007. Standard IVF or ICSI protocol, embryo freezing, and ET. The number of 2 pronuclear (2PN) embryos created and suitable for cryopreservation or transfer. No statistically significant differences were observed between preservation and male factor groups for number of embryos, number of oocytes, or amount of gonadotropin needed to stimulate follicular development. Peak serum E(2) levels were significantly lower for women with disease-seeking fertility preservation. Women facing chemotherapy as treatment for cancer or systemic autoimmune disease infrequently undergo fertility preservation. If offered this potentially fertility-preserving option, these data suggest equivalent embryo yield compared with women with infertile male partners. Our data report no significant complications in subsequent births in those who sought fertility preservation, which is informative and encouraging for these women and their providers. Copyright © 2011 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Intense pumping and time- and frequency-resolved CARS for driving and tracking structural deformation and recovery of liquid nitromethane molecules

NASA Astrophysics Data System (ADS)

Wang, Chang; Wu, Hong-lin; Song, Yun-fei; He, Xing; Yang, Yan-qiang; Tan, Duo-wang

2015-11-01

A modified CARS technique with an intense nonresonant femtosecond laser is presented to drive the structural deformation of liquid nitromethane molecules and track their structural relaxation process. The CARS spectra reveal that the internal rotation of the molecule can couple with the CN symmetric stretching vibration and the molecules undergo ultrafast structural deformation of the CH3 groups from 'opened umbrella' to 'closed umbrella' shape, and then experience a structural recovery process within 720 fs.

More daytime sleeping predicts less functional recovery among older people undergoing inpatient post-acute rehabilitation.

PubMed

Alessi, Cathy A; Martin, Jennifer L; Webber, Adam P; Alam, Tarannum; Littner, Michael R; Harker, Judith O; Josephson, Karen R

2008-09-01

To study the association between sleep/wake patterns among older adults during inpatient post-acute rehabilitation and their immediate and long-term functional recovery Prospective, observational cohort study. Two inpatient post-acute rehabilitation sites (one community and one Veterans Administration). Older patients (aged > or = 65 years, N = 245) admitted for inpatient post-acute rehabilitation. None. Based on 7-day wrist actigraphy during the rehabilitation stay, mean nighttime percent sleep was only 52.2% and mean daytime percent sleep was 15.8% (16.3% based on structured behavioral observations). Using the Pittsburgh Sleep Quality Index (PSQI), participants reported their sleep was worse during rehabilitation compared to their premorbid sleep. Functional recovery between admission and discharge from rehabilitation (measured by the motor component of the Functional Independence Measure) was not significantly associated with reported sleep quality (PSQI scores) or actigraphically measured nighttime sleep. However, more daytime percent sleep (estimated by actigraphy and observations) during the rehabilitation stay was associated with less functional recovery from admission to discharge, even after adjusting for other significant predictors of functional recovery (mental status, hours of rehabilitation therapy received, rehospitalization, and reason for admission; adjusted R2= 0.267, P < 0.0001). More daytime sleeping during rehabilitation remained a significant predictor of less functional recovery in adjusted analyses at 3-month follow-up. Sleep disturbance is common among older people undergoing inpatient post-acute rehabilitation. These data suggest that more daytime sleeping during the rehabilitation stay is associated with less functional recovery for up to three months after admission for rehabilitation.

The centrosomin CM2 domain is a multi-functional binding domain with distinct cell cycle roles.

PubMed

Citron, Y Rose; Fagerstrom, Carey J; Keszthelyi, Bettina; Huang, Bo; Rusan, Nasser M; Kelly, Mark J S; Agard, David A

2018-01-01

The centrosome serves as the main microtubule-organizing center in metazoan cells, yet despite its functional importance, little is known mechanistically about the structure and organizational principles that dictate protein organization in the centrosome. In particular, the protein-protein interactions that allow for the massive structural transition between the tightly organized interphase centrosome and the highly expanded matrix-like arrangement of the mitotic centrosome have been largely uncharacterized. Among the proteins that undergo a major transition is the Drosophila melanogaster protein centrosomin that contains a conserved carboxyl terminus motif, CM2. Recent crystal structures have shown this motif to be dimeric and capable of forming an intramolecular interaction with a central region of centrosomin. Here we use a combination of in-cell microscopy and in vitro oligomer assessment to show that dimerization is not necessary for CM2 recruitment to the centrosome and that CM2 alone undergoes significant cell cycle dependent rearrangement. We use NMR binding assays to confirm this intramolecular interaction and show that residues involved in solution are consistent with the published crystal structure and identify L1137 as critical for binding. Additionally, we show for the first time an in vitro interaction of CM2 with the Drosophila pericentrin-like-protein that exploits the same set of residues as the intramolecular interaction. Furthermore, NMR experiments reveal a calcium sensitive interaction between CM2 and calmodulin. Although unexpected because of sequence divergence, this suggests that centrosomin-mediated assemblies, like the mammalian pericentrin, may be calcium regulated. From these results, we suggest an expanded model where during interphase CM2 interacts with pericentrin-like-protein to form a layer of centrosomin around the centriole wall and that at the onset of mitosis this population acts as a nucleation site of intramolecular centrosomin interactions that support the expansion into the metaphase matrix.

Dynamic structure of confined shocks undergoing sudden expansion

NASA Astrophysics Data System (ADS)

Abate, G.; Shyy, W.

2002-01-01

The gas dynamic phenomenon associated with a normal shock wave within a tube undergoing a sudden area expansion consists of highly transient flow and diffraction that give rise to turbulent, compressible, vortical flows. These interactions can occur at time scales typically ranging from micro- to milliseconds. In this article, we review recent experimental and numerical results to highlight the flow phenomena and main physical mechanisms associated with this geometry. The topics addressed include time-accurate shock and vortex locations, flowfield evolution and structure, wall-shock Mach number, two- vs. three-dimensional sudden expansions, and the effect of viscous dissipation on planar shock-front expansions. Between axisymmetric and planar geometries, the flow structure evolves very similarly early on in the sudden expansion process (i.e., within the first two shock tube diameters). Both numerical and experimental studies confirm that the trajectory of the vortex formed at the expansion corner is convected into the flowfield faster in the axisymmetric case than the planar case. The lateral propagation of the vortices correlates very well between axisymmetric and planar geometries. In regard to the rate of dissipation of turbulent kinetic energy (TKE) for a two-dimensional planar shock undergoing a sudden expansion within a confined chamber, calculations show that the solenoidal dissipation is confined to the region of high strain rates arising from the expansion corner. Furthermore, the dilatational dissipation is concentrated mainly at the curvature of the incident, reflected, and barrel shock fronts. The multiple physical mechanisms identified, including shock-strain rate interaction, baroclinic effect, vorticity generation, and different aspects of viscous dissipation, have produced individual and collective flow structures observed experimentally.

Importance of tissue perfusion in ST segment elevation myocardial infarction patients undergoing reperfusion strategies: role of adenosine.

PubMed

Forman, Mervyn B; Jackson, Edwin K

2007-11-01

High risk ST segment elevation myocardial infarction (STEMI) patients undergoing reperfusion therapy continue to exhibit significant morbidity and mortality due in part to myocardial reperfusion injury. Importantly, preclinical studies demonstrate that progressive microcirculatory failure (the "no-reflow" phenomenon) contributes significantly to myocardial reperfusion injury. Diagnostic techniques to measure tissue perfusion have validated this concept in humans, and it is now clear that abnormal tissue perfusion occurs frequently in STEMI patients undergoing reperfusion therapy. Moreover, because tissue perfusion correlates poorly with epicardial blood flow (TIMI flow grade), clinical studies show that tissue perfusion is an independent predictor of early and late mortality in STEMI patients and is associated with infarct size, ventricular function, CHF and ventricular arrhythmias. The mechanisms responsible for abnormal tissue perfusion are multifactorial and include both mechanical obstruction and vasoconstrictor humoral factors. Adenosine, an endogenous nucleoside, maintains microcirculatory flow following reperfusion by activating four well-characterized extracellular receptors. Because activation of adenosine receptors attenuates the mechanical and functional mechanisms leading to the "no reflow" phenomenon and activates other cardioprotective pathways as well, it is not surprising that both experimental and clinical studies show striking myocardial salvage with intravenous infusions of adenosine administered in the peri-reperfusion period. For example, a post hoc analysis of the AMISTAD II trial indicates a significant reduction in 1 and 6-month mortality in STEMI patients undergoing reperfusion therapy who are treated with adenosine within 3 hours of symptoms. In conclusion, adenosine's numerous cardioprotective effects, including attenuation of the "no-reflow" phenomenon, support its use in high risk STEMI undergoing reperfusion.

Factors associated with disposition of cryopreserved reproductive tissue.

PubMed

Styer, Aaron K; Cekleniak, Natalie A; Legedza, Anna; Mutter, George L; Hornstein, Mark D

2003-09-01

To study patient characteristics associated with the preferences for the disposition of cryopreserved semen and embryos in the event of death or divorce. Retrospective exploratory study. Tertiary care academic medical center. One hundred twelve men banking sperm, 54 female patients (partners of men banking sperm) undergoing in vitro fertilization (IVF), and 112 women undergoing IVF who were not partners of men banking sperm. Male patients banking sperm and couples undergoing IVF completed a standard consent form detailing their desired dispositions (disposal or release to a surviving party) of cryopreserved sperm and embryos in the event of death or divorce. Effect of marital status, age, reason for sperm banking, infertility diagnosis, partner status (single or significant-other partner) on sperm, and embryo disposition choice. In the event of death, married men were 5.5 times more likely to release banked sperm to a surviving party than were single men. The estimated odds of giving sperm to a survivor were 1.07 times greater with every 1-year increase in age. The choice of sperm disposal was significantly related to the banking reason for the case of banking prior to chemotherapy and/or radiation for malignancy. In the case of male death, the decisions of couples undergoing IVF for embryo disposition agreed with choices of male patients for sperm disposition approximately 33% of the time more often than by chance alone. Decisions surrounding disposition of cryopreserved sperm are significantly associated with marital status, age, and reason for banking sperm. Respective choices of sperm and embryo disposition in couples undergoing IVF were similar in the situation of male death.

Evaluation of a transient, simultaneous, arbitrary Lagrange-Euler based multi-physics method for simulating the mitral heart valve.

PubMed

Espino, Daniel M; Shepherd, Duncan E T; Hukins, David W L

2014-01-01

A transient multi-physics model of the mitral heart valve has been developed, which allows simultaneous calculation of fluid flow and structural deformation. A recently developed contact method has been applied to enable simulation of systole (the stage when blood pressure is elevated within the heart to pump blood to the body). The geometry was simplified to represent the mitral valve within the heart walls in two dimensions. Only the mitral valve undergoes deformation. A moving arbitrary Lagrange-Euler mesh is used to allow true fluid-structure interaction (FSI). The FSI model requires blood flow to induce valve closure by inducing strains in the region of 10-20%. Model predictions were found to be consistent with existing literature and will undergo further development.

Regional variations in the density and arrangement of elastic fibres in the anulus fibrosus of the human lumbar disc

PubMed Central

Smith, Lachlan J; Fazzalari, Nicola L

2006-01-01

Elastic fibres are critical components of the extracellular matrix in dynamic biological structures that undergo extension and recoil. Their presence has been demonstrated in the anulus fibrosus of the human lumbar intervertebral disc; however, a detailed regional analysis of their density and arrangement has not been undertaken, limiting our understanding of their structural and functional roles. In this investigation we have quantitatively described regional variations in elastic fibre density in the anulus fibrosus of the human L3–L4 intervertebral disc using histochemistry and light microscopy. Additionally, a multiplanar comparison of patterns of elastic fibre distribution in the intralamellar and interlamellar zones was undertaken. Novel imaging techniques were developed to facilitate the visualization of elastic fibres otherwise masked by dense surrounding matrix. Elastic fibre density was found to be significantly higher in the lamellae of the posterolateral region of the anulus than the anterolateral, and significantly higher in the outer regions than the inner, suggesting that elastic fibre density in each region of the anulus is commensurate with the magnitude of the tensile deformations experienced in bending and torsion. Elastic fibre arrangments in intralamellar and interlamellar zones were shown to be architecturally distinct, suggesting that they perform multiple functional roles within the anulus matrix structural hierarchy. PMID:16928204

Evaluation of three presets for four-dimensional cone beam CT in lung radiotherapy verification by visual grading analysis.

PubMed

Kember, Sally A; Hansen, Vibeke N; Fast, Martin F; Nill, Simeon; McDonald, Fiona; Ahmed, Merina; Thomas, Karen; McNair, Helen A

2016-07-01

To evaluate three image acquisition presets for four-dimensional cone beam CT (CBCT) to identify an optimal preset for lung tumour image quality while minimizing dose and acquisition time. Nine patients undergoing radical conventionally fractionated radiotherapy for lung cancer had verification CBCTs acquired using three presets: Preset 1 on Day 1 (11 mGy dose, 240 s acquisition time), Preset 2 on Day 2 (9 mGy dose, 133 s acquisition time) and Preset 3 on Day 3 (9 mGy dose, 67 s acquisition time). The clarity of the tumour and other thoracic structures, and the acceptability of the match, were retrospectively graded by visual grading analysis (VGA). Logistic regression was used to identify the most appropriate preset and any factors that might influence the result. Presets 1 and 2 met a clinical requirement of 75% of structures to be rated "Clear" or above and 75% of matches to be rated "Acceptable" or above. Clarity is significantly affected by preset, patient, observer and structure. Match acceptability is significantly affected by preset. The application of VGA in this initial study enabled a provisional selection of an optimal preset (Preset 2) to be made. This was the first application of VGA to the investigation of presets for CBCT.

46 CFR 115.600 - Drydock examination, internal structural examination, and underwater survey intervals.

Code of Federal Regulations, 2010 CFR

2010-10-01

... a United States port, it must undergo the required examination before sailing. (c) If your vessel is... hull exams and two internal structural exams within any five-year period. If a vessel completes a satisfactory alternate hull exam, with the underwater survey portion conducted predominantly by an approved...

Reforms in German Higher Education: Implementing and Adapting Anglo-American Organizational and Management Structures at German Universities

ERIC Educational Resources Information Center

Liefner, Ingo; Schatzl, Ludwig; Schroder, Thomas

2004-01-01

Currently, the German higher education system is undergoing drastic reform. Competitive structures and funding mechanisms are being introduced that are already successfully used in other countries. However, critics state that cultural differences prevent the effective application, in German universities, of funding mechanisms and incentives…

Rules and Construction Effects in Learning the Argument Structure of Verbs

ERIC Educational Resources Information Center

Demuth, Katherine; Machobane, 'Malillo; Moloi, Francina

2003-01-01

Theorists of language acquisition have long debated the means by which children learn the argument structure of verbs (e.g. Bowerman, 1974, 1990; Pinker, 1984, 1989; Tomasello, 1992). Central to this controversy has been the possible role of verb semantics, especially in learning which verbs undergo dative-shift alternation in languages like…

46 CFR 169.229 - Drydock examination, internal structural examination, and underwater survey intervals.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., and underwater survey intervals. 169.229 Section 169.229 Shipping COAST GUARD, DEPARTMENT OF HOMELAND... Hauling Out § 169.229 Drydock examination, internal structural examination, and underwater survey... period unless it has been approved to undergo an underwater survey (UWILD) under § 169.230 of this part...

Predictive factors for complications in children with esophageal atresia and tracheoesophageal fistula.

PubMed

Shah, R; Varjavandi, V; Krishnan, U

2015-04-01

The objective of this study was to describe the incidence of complications in children with esophageal atresia (EA) with or without tracheoesophageal fistula (TEF) at a tertiary pediatric hospital and to identify predictive factors for their occurrence. A retrospective chart review of 110 patients born in or transferred to Sydney Children's Hospital with EA/TEF between January 1999 and December 2010 was done. Univariate and multivariate regression analyses were performed to identify predictive factors for the occurrence of complications in these children. From univariate analysis, early esophageal stricture formation was more likely in children with 'long-gap' EA (odds ratio [OR] = 16.32). Patients with early strictures were more likely to develop chest infections (OR = 3.33). Patients with severe tracheomalacia were more likely to experience 'cyanotic/dying' (OR = 180) and undergo aortopexy (OR = 549). Patients who had gastroesophageal reflux disease were significantly more likely to require fundoplication (OR = 10.83) and undergo aortopexy (OR = 6.417). From multivariate analysis, 'long-gap' EA was a significant predictive factor for late esophageal stricture formation (P = 0.007) and for gastrostomy insertion (P = 0.001). Reflux was a significant predictive factor for requiring fundoplication (P = 0.007) and gastrostomy (P = 0.002). Gastrostomy insertion (P = 0.000) was a significant predictive factor for undergoing fundoplication. Having a prior fundoplication (P = 0.001) was a significant predictive factor for undergoing a subsequent aortopexy. Predictive factors for the occurrence of complications post EA/TEF repair were identified in this large single centre pediatric study. © 2014 International Society for Diseases of the Esophagus.

Evaluating the efficacy of lavender aromatherapy on peripheral venous cannulation pain and anxiety: A prospective, randomized study.

PubMed

Karaman, Tugba; Karaman, Serkan; Dogru, Serkan; Tapar, Hakan; Sahin, Aynur; Suren, Mustafa; Arici, Semih; Kaya, Ziya

2016-05-01

This study was designed to evaluate the effectiveness of lavender aromatherapy on pain, anxiety, and level of satisfaction associated with the peripheral venous cannulation (PVC) in patients undergoing surgery. One hundred and six patients undergoing surgery were randomized to receive aromatherapy with lavender essential oil (the lavender group) or a placebo (the control group) during PVC. The patients' pain, anxiety, and satisfaction scores were measured. There was no statistically significantly difference between the groups in terms of demographic data. After cannulation, the pain and anxiety scores (anxiety 2) of the patients in the lavender group were significantly lower than the control group (for p = 0.01 for pain scores; p < 0.001 for anxiety 2 scores). In addition, patient satisfaction was significantly higher in the lavender group than in the control group (p = 0.003). Lavender aromatherapy had beneficial effects on PVC pain, anxiety, and satisfaction level of patients undergoing surgery. Copyright © 2016 Elsevier Ltd. All rights reserved.

High-pressure protein crystallography of hen egg-white lysozyme

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamada, Hiroyuki; Nagae, Takayuki; Watanabe, Nobuhisa, E-mail: nobuhisa@nagoya-u.jp

The crystal structure of hen egg-white lysozyme (HEWL) was analyzed under pressures of up to 950 MPa. The high pressure modified the conformation of the molecule and induced a novel phase transition in the tetragonal crystal of HEWL. Crystal structures of hen egg-white lysozyme (HEWL) determined under pressures ranging from ambient pressure to 950 MPa are presented. From 0.1 to 710 MPa, the molecular and internal cavity volumes are monotonically compressed. However, from 710 to 890 MPa the internal cavity volume remains almost constant. Moreover, as the pressure increases to 950 MPa, the tetragonal crystal of HEWL undergoes a phasemore » transition from P4{sub 3}2{sub 1}2 to P4{sub 3}. Under high pressure, the crystal structure of the enzyme undergoes several local and global changes accompanied by changes in hydration structure. For example, water molecules penetrate into an internal cavity neighbouring the active site and induce an alternate conformation of one of the catalytic residues, Glu35. These phenomena have not been detected by conventional X-ray crystal structure analysis and might play an important role in the catalytic activity of HEWL.« less

Vibration energy harvesting based monitoring of an operational bridge undergoing forced vibration and train passage

NASA Astrophysics Data System (ADS)

Cahill, Paul; Hazra, Budhaditya; Karoumi, Raid; Mathewson, Alan; Pakrashi, Vikram

2018-06-01

The application of energy harvesting technology for monitoring civil infrastructure is a bourgeoning topic of interest. The ability of kinetic energy harvesters to scavenge ambient vibration energy can be useful for large civil infrastructure under operational conditions, particularly for bridge structures. The experimental integration of such harvesters with full scale structures and the subsequent use of the harvested energy directly for the purposes of structural health monitoring shows promise. This paper presents the first experimental deployment of piezoelectric vibration energy harvesting devices for monitoring a full-scale bridge undergoing forced dynamic vibrations under operational conditions using energy harvesting signatures against time. The calibration of the harvesters is presented, along with details of the host bridge structure and the dynamic assessment procedures. The measured responses of the harvesters from the tests are presented and the use the harvesters for the purposes of structural health monitoring (SHM) is investigated using empirical mode decomposition analysis, following a bespoke data cleaning approach. Finally, the use of sequential Karhunen Loeve transforms to detect train passages during the dynamic assessment is presented. This study is expected to further develop interest in energy-harvesting based monitoring of large infrastructure for both research and commercial purposes.

Pattern of episiotomy use & its immediate complications among vaginal deliveries in 18 tertiary care hospitals in India

PubMed Central

Singh, Shalini; Thakur, Tushita; Chandhiok, Nomita; Dhillon, Balwan Singh

2016-01-01

Background & objectives: In developed countries, efforts have been made to restrict episiotomy practice. However, in developing countries the episiotomy rates continue to be high. This study was conducted to evaluate the pattern of episiotomy use and its immediate complications among women delivering at tertiary level public hospitals in India. Methods: Prospective data of all women undergoing vaginal delivery including instrumental delivery were collected daily from the labour room registers of the 18 tertiary care hospitals on a structured proforma. Weekly data from all sites were sent to a central unit for compilation and analysis. Odds ratio was used to compare the proportion of genital trauma among women with and without episiotomy both in nulliparous and multiparous women. Results: Among 1,20,243 vaginal deliveries, episiotomy was performed in 63.4 per cent (n=76,305) cases. Nulliparaous women were 8.8 times more likely to undergo episiotomy than multiparous women. The various genital tract injuries reported were first degree perineal tear (n=4805, 3.9%), second degree perineal tear (n=1082, 0.9%), third and fourth degree perineal tear (n=186, 0.2%), anterior vaginal trauma requiring suturing (n=490, 0.4%), extension of episiotomy/vaginal laceration/excessive bleeding from episiotomy or tear (n=177, 0.15%), vulval/vaginal haematoma (n=70, 0.06%) and cervical tear (n=108, 0.08%). The combined rate of third and fourth degree perineal tears was observed to be significantly lower (P<0.001) among nullipara who received episiotomy (0.13%) compared to those who delivered without episiotomy (0.62%). Interpretations & conclusions: Significantly lower rates of third or fourth degree perineal tear were seen among nulliparous women undergoing episiotomy. The risk and benefit of episiotomy and its complications need to be evaluated through randomized clinical trials in the Indian context. PMID:27377504

Prevalence and Prognostic Significance of Right Ventricular Systolic Dysfunction in Patients Undergoing Transcatheter Aortic Valve Implantation.

PubMed

Lindsay, Alistair C; Harron, Katie; Jabbour, Richard J; Kanyal, Ritesh; Snow, Thomas M; Sawhney, Paramvir; Alpendurada, Francisco; Roughton, Michael; Pennell, Dudley J; Duncan, Alison; Di Mario, Carlo; Davies, Simon W; Mohiaddin, Raad H; Moat, Neil E

2016-07-01

Cardiovascular magnetic resonance (CMR) can provide important structural information in patients undergoing transcatheter aortic valve implantation. Although CMR is considered the standard of reference for measuring ventricular volumes and mass, the relationship between CMR findings of right ventricular (RV) function and outcomes after transcatheter aortic valve implantation has not previously been reported. A total of 190 patients underwent 1.5 Tesla CMR before transcatheter aortic valve implantation. Steady-state free precession sequences were used for aortic valve planimetry and to assess ventricular volumes and mass. Semiautomated image analysis was performed by 2 specialist reviewers blinded to patient treatment. Patient follow-up was obtained from the Office of National Statistics mortality database. The median age was 81.0 (interquartile range, 74.9-85.5) years; 50.0% were women. Impaired RV function (RV ejection fraction ≤50%) was present in 45 (23.7%) patients. Patients with RV dysfunction had poorer left ventricular ejection fractions (42% versus 69%), higher indexed left ventricular end-systolic volumes (96 versus 40 mL), and greater indexed left ventricular mass (101 versus 85 g/m(2); P<0.01 for all) than those with normal RV function. Median follow-up was 850 days; 21 of 45 (46.7%) patients with RV dysfunction died, compared with 43 of 145 (29.7%) patients with normal RV function (P=0.035). After adjustment for significant baseline variables, both RV ejection fraction ≤50% (hazard ratio, 2.12; P=0.017) and indexed aortic valve area (hazard ratio, 4.16; P=0.025) were independently associated with survival. RV function, measured on preprocedural CMR, is an independent predictor of mortality after transcatheter aortic valve implantation. CMR assessment of RV function may be important in the risk stratification of patients undergoing transcatheter aortic valve implantation. © 2016 American Heart Association, Inc.

Rheological changes of polyamide 12 under oscillatory shear

NASA Astrophysics Data System (ADS)

Mielicki, C.; Gronhoff, B.; Wortberg, J.

2014-05-01

Changes in material properties as well as process deviation prevent Laser Sintering (LS) technology from manufacturing of quality assured parts in a series production. In this context, the viscosity of Polyamide 12 (PA12) is assumed to possess the most significant influence, as it determines the sintering velocity, the resistance towards melt formation and the bonding strength of sintered layers. Moreover, the viscosity is directly related to the structure of the molten polymer. In particular, it has been recently reported that LS process conditions lead to structural changes of PA12 affecting viscosity and coalescence of adjacent polymer particles, i.e. melt formation significantly. Structural change of PA12 was understood as a post condensation. Its influence on viscosity was described by a time and temperature depending rheological model whereas time dependence was considered by a novel structural change shift factor which was derived from melt volume rate data. In combination with process data that was recorded using online thermal imaging, the model is suitable to control the viscosity (processability of the material) as result of material and process properties. However, as soon as laser energy is exposed to the powder bed PA12 undergoes a phase transition from solid to molten state. Above the melting point, structural change is expected to occur faster due to a higher kinetic energy and free volume of the molten polymer. Oscillatory shear results were used to study the influence of aging time and for validation of the novel structural change shift factor and its model parameters which were calibrated based on LS processing condition.

View south of sail loft mid loft area. Note ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

View south of sail loft - mid- loft area. Note inflatable boats undergoing pressure testing. - Naval Base Philadelphia-Philadelphia Naval Shipyard, Structure Shop, League Island, Philadelphia, Philadelphia County, PA

Energy Delivery Systems for Treatment of Benign Prostatic Hyperplasia

PubMed Central

2006-01-01

Executive Summary Objective The Ontario Health Technology Advisory Committee asked the Medical Advisory Secretariat (MAS) to conduct a health technology assessment on energy delivery systems for the treatment of benign prostatic hyperplasia (BPH). Clinical Need: Target Population and Condition BPH is a noncancerous enlargement of the prostate gland and the most common benign tumour in aging men. (1) It is the most common cause of lower urinary tract symptoms (LUTS) and bladder outlet obstruction (BOO) and is an important cause of diminished quality of life among aging men. (2) The primary goal in the management of BPH for most patients is a subjective improvement in urinary symptoms and quality of life. Until the 1930s, open prostatectomy, though invasive, was the most effective form of surgical treatment for BPH. Today, the benchmark surgical treatment for BPH is transurethral resection of the prostate (TURP), which produces significant changes of all subjective and objective outcome parameters. Complications after TURP include hemorrhage during or after the procedure, which often necessitates blood transfusion; transurethral resection (TUR) syndrome; urinary incontinence; bladder neck stricture; and sexual dysfunction. A retrospective review of 4,031 TURP procedures performed by one surgeon between 1979 and 2003 showed that the incidence of complications was 2.4% for blood transfusion, 0.3% for TUR syndrome, 1.5% for hemostatic procedures, 2.8% for bladder neck contracture, and 1% for urinary stricture. However, the incidence of blood transfusion and TUR syndrome decreased as the surgeon’s skills improved. During the 1990s, a variety of endoscopic techniques using a range of energy sources have been developed as alternative treatments for BPH. These techniques include the use of light amplification by stimulated emission of radiation (laser), radiofrequency, microwave, and ultrasound, to heat prostate tissue and cause coagulation or vaporization. In addition, new electrosurgical techniques that use higher amounts of energy to cut, coagulate, and vaporize prostatic tissue have entered the market as competitors to TURP. The driving force behind these new treatment modalities is the potential of producing good hemostasis, thereby reducing catheterization time and length of hospital stay. Some have the potential to be used in an office environment and performed under local anesthesia. Therefore, these new procedures have the potential to rival TURP if their effectiveness is proven over the long term. The Technology Being Reviewed The following energy-based techniques were considered for assessment: transurethral electrovaporization of the prostate (TUVP) transurethral electrovapor resection of the prostate (TUVRP) transurethral electrovaporization of the prostate using bipolar energy (plasmakinetic vaporization of the prostate [PKVP]) visual laser ablation of the prostate (VLAP) transurethral ultrasound guided laser incision prostatectomy (TULIP) contact laser vaporization of the prostate (CLV) interstitial laser coagulation (ILC) holmium laser resection of the prostate (HoLRP) holmium laser enucleation of the prostate (HoLEP) holmium laser ablation of the prostate (HoLAP) potassium titanyl phosphate (KTP) laser transurethral microwave thermotherapy (TUMT) transurethral needle ablation (TUNA) Review Strategy A search of electronic databases (OVID MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations, EMBASE, The Cochrane Library, and the International Agency for Health Technology Assessment [INAHTA] database) was undertaken to identify evidence published from January 1, 2000 to June 21, 2006. The search was limited to English-language articles and human studies. The literature search identified 284 citations, of which 38 randomized controlled trials (RCTs) met the inclusion criteria. Since the application of high-power (80 W) KTP laser (photoselective vaporization of the prostate [PVP]) has been supported in the United States and has resulted in a rapid diffusion of this technology in the absence of any RCTs, the MAS decided that any comparative studies on PVP should be identified and evaluated. Hence, the literature was searched and one prospective cohort study (3) was identified but evaluated separately. Findings of Literature Review and Analysis Meta-analysis of the results of RCTs shows that monopolar electrovaporization is as clinically effective as TURP for the relief of urinary symptoms caused by BPH (based on 5-year follow-up data). Meta-analysis of the results of RCTs shows that bipolar electrovaporization (PKVP) is clinically as effective as TURP for the relief of urinary symptoms caused by BPH (based on 1-year follow-up data). Two of the three RCTs on VLAP have shown that patients undergoing VLAP had a significantly lesser improvement in urinary symptom scores compared with patients undergoing TURP. RCTs showed that the time to catheter removal was significantly longer in patients undergoing VLAP compared with patients undergoing TURP. Meta-analysis of the rate of reoperation showed that patients undergoing VLAP had a significantly higher rate of reoperation compared with patients undergoing TURP. Meta-analysis showed that patients undergoing CLV had a significantly lesser improvement in urinary symptom scores compared with TURP at 2 years and at 3 or more years of follow-up. Two RCTs with 6-month and 2-year follow-up showed similar improvement in symptom scores for ILC and TURP. Time to catheter removal was significantly longer in patients undergoing ILC compared with patients undergoing TURP. The results of RCTs on HoLEP with 1-year follow-up showed excellent clinical outcomes with regard to the urinary symptom score and peak urinary flow. Meta-analysis showed that at 1-year follow-up, patients undergoing HoLEP had a significantly greater improvement in urinary symptom scores and peak flow rate compared with patients undergoing TURP. Procedural time is significantly longer in HoLEP compared with TURP. The results of one RCT with 4-year follow-up showed that HoLRP and TURP provided equivalent improvement in urinary symptom scores. The results of one RCT with 1-year follow-up showed that patients undergoing KTP had a lesser improvement in urinary symptom scores than did patients undergoing TURP. However, the results were not significant at longer-term follow-up periods. Two RCTs that provided 3-year follow-up data reported that patients undergoing TUMT had a significantly lesser improvement in symptom score compared with patients undergoing TURP. RCTs reported a longer duration of catheterization for TUMT compared with TURP (P values are not reported). The results of a large RCT with 5-year follow-up showed a significantly lesser improvement in symptom scores in patients undergoing TUNA compared with patients undergoing TURP. Meta-analysis of the rate of reoperation showed that patients undergoing TUNA had a significantly higher rate of reoperation compared with patients undergoing TURP. Based on the results of RCTs, TURP is associated with a 0.5% risk of TUR syndrome, while no cases of TUR syndrome have been reported in patients undergoing monopolar or bipolar electrovaporization, laser-based procedures, TUMT, or TUNA. Based on the results of RCTs, the rate of blood transfusion ranges from 0% to 8.3% in patients undergoing TURP. The rate is about 1.7% in monopolar electrovaporization, 1.4% in bipolar electrovaporization, and 0.4% in the VLAP procedure. No patients undergoing CLV, ILC, HoLEP, HoLRP, KTP, TUMT, and TUNA required blood transfusion. The mean length of hospital stay is between 2 and 5 days for patients undergoing TURP, about 3 days for electrovaporization, about 2 to 4 days for Nd:YAG laser procedures, and about 1 to 2 days for holmium laser procedures. TUMT and TUNA can each be performed as a day procedure in an outpatient setting (0.5 and 1 day respectively). Based on a prospective cohort study, PVP is clinically as effective as TURP for the relief of urinary symptoms caused by BPH (based on 6-month follow-up data). Time to catheter removal was significantly shorter in patients undergoing PVP than in those undergoing TURP. Operating room time was significantly longer in PVP than in TURP. PVP has the potential to reduce health care expenses due to shorter hospital stays. Economic Analysis In the three most recent fiscal years (FY) reported, an average of approximately 5,000 TURP procedures per year were performed in Ontario. From FY 2002 to FY 2004, the total number of surgical interventions decreased by approximately 500 procedures. During this time, the increase in costs of drugs to the government was estimated at approximately $10 million (Cdn); however, there was a concurrent decrease in costs due to a decline in the total number of surgical procedures, estimated at approximately $1.9 million (Cdn). From FY 2002 to FY 2004, the increase in costs associated with the increase in utilization of drugs for the treatment of BPH translates into $353 (Cdn) per patient while the cost savings associated with a decrease in the total number of surgical procedures translates into a savings of $3,906 (Cdn) per patient. The following table summarizes the change in the current budget, depending on various estimates of the total percentage of the 5,000 TURP procedures that might be replaced by other energy-based interventions for the treatment of BPH in the future. Executive Summary Table 1: Budget Impact With Various Estimates of the Percentage of TURP Procedures Captured by Energy-based Interventions for the Treatment of BPH Technology Cost perprocedure, $ Budget Impact of 25% diffusion, $M Budget Impact of 50% diffusion, $M Budget Impact of 75% diffusion, $M Budget Impact of 100% diffusion, $M Incremental Budget Impact, $M TURP 3,887 19.4 Bipolar Electrovaporization 4,011 19.6 19.7 19.9 20.0 0.6 Monopolar Electrovaporization 4,130 19.7 20.0 20.3 20.6 1.2 TUMT 1,529 16.5 13.5 10.6 7.6 (11.8)  TUNA 4,804 20.6 21.7 22.9 24.0 4.6 PVP 1,184 16.0 12.7 9.3 5.9 (13.5)   Holmium Laser 3,892 19.4 19.4 19.4 19.4 0.02 VLAP Nd:YAG 4,663 20.4 21.4 22.3 23.3 3.9 CLAP Nd:YAG 4,615 20.3 21.2 22.4 23.0 3.6 * All costs are in Canadian currency. Parentheses indicative of cost reduction. PMID:23074487

Haemorrhagic cholecystitis in a newly anticoagulated patient.

PubMed

Kinnear, Ned; Hennessey, Derek Barry; Thomas, Rebecca

2017-04-12

A 74-year-old man undergoing rehabilitation after pneumonia developed right upper quadrant abdominal pain. Five days earlier he had been commenced on apixaban for a new diagnosis of atrial fibrillation. Ultrasound and CT scans revealed an acalculous grossly thickened gallbladder, with high attenuation non-echogenic material both within and surrounding the structure. Active contrast extravasation was seen at the neck. On laparotomy, a perforated internally bleeding gallbladder containing a single calculus was found, with significant free blood within the abdomen. After cholecystectomy, the patient recovered slowly in hospital before nursing home placement. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Modeling the Relationship Between Porosity and Permeability During Oxidation of Ablative Materials

NASA Technical Reports Server (NTRS)

Thornton, John M.; Panerai, Francesco; Ferguson, Joseph C.; Borner, Arnaud; Mansour, Nagi N.

2017-01-01

The ablative materials used in thermal protection systems (TPS) undergo oxidation during atmospheric entry which leads to an in-depth change in both permeability and porosity. These properties have a significant affect on heat transfer in a TPS during entry. X-ray micro-tomography has provided 3D images capturing the micro-structure of TPS materials. In this study, we use micro-tomography based simulations to create high-fidelity models relating permeability to porosity during oxidation of FiberForm, the carbon fiber preform of the Phenolic Impregnated Carbon Ablator (PICA) often used as a TPS material. The goal of this study is to inform full-scale models and reduce uncertainty in TPS modeling.

Effectiveness of group cognitive behavioral therapy with mindfulness in end-stage renal disease hemodialysis patients.

PubMed

Sohn, Bo Kyung; Oh, Yun Kyu; Choi, Jung-Seok; Song, Jiyoun; Lim, Ahyoung; Lee, Jung Pyo; An, Jung Nam; Choi, Hee-Jeong; Hwang, Jae Yeon; Jung, Hee-Yeon; Lee, Jun-Young; Lim, Chun Soo

2018-03-01

Many patients with end-stage renal disease (ESRD) undergoing hemodialysis (HD) experience depression. Depression influences patient quality of life (QOL), dialysis compliance, and medical comorbidity. We developed and applied a group cognitive behavioral therapy (CBT) program including mindfulness meditation for ESRD patients undergoing HD, and measured changes in QOL, mood, anxiety, perceived stress, and biochemical markers. We conducted group CBT over a 12-week period with seven ESRD patients undergoing HD and suffering from depression. QOL, mood, anxiety, and perceived stress were measured at baseline and at weeks 8 and 12 using the World Health Organization Quality of Life scale, abbreviated version (WHOQOL-BREF), the Beck Depression Inventory II (BDI-II), the Hamilton Rating Scale for Depression (HAM-D), the Beck Anxiety Inventory (BAI), and the Perceived Stress Scale (PSS). Biochemical markers were measured at baseline and after 12 weeks. The Temperament and Character Inventory was performed to assess patient characteristics before starting group CBT. The seven patients showed significant improvement in QOL, mood, anxiety, and perceived stress after 12 weeks of group CBT. WHOQOL-BREF and the self-rating scales, BDI-II and BAI, showed continuous improvement across the 12-week period. HAM-D scores showed significant improvement by week 8; PSS showed significant improvement after week 8. Serum creatinine levels also improved significantly following the 12 week period. In this pilot study, a CBT program which included mindfulness meditation enhanced overall mental health and biochemical marker levels in ESRD patients undergoing HD.

Effects of carprofen and meloxicam on C-reactive protein, ceruloplasmin, and fibrinogen concentrations in dogs undergoing ovariohysterectomy.

PubMed

Kum, Cavit; Voyvoda, Huseyin; Sekkin, Selim; Karademir, Umit; Tarimcilar, Tugrul

2013-10-01

To evaluate the effects of perioperative oral administration of carprofen and meloxicam on concentrations of 3 acute-phase proteins in dogs undergoing elective ovariohysterectomy (OVH). 18 healthy adult anestrous female dogs undergoing elective OVH. Dogs were allocated to 3 groups (6 dogs/group). A placebo treatment, carprofen (2.0 mg/kg), or meloxicam (0.2 mg/kg) was orally administered to the dogs of the respective groups. The initial doses were administered 30 minutes before premedication prior to OVH; additional doses were administered once daily for 4 days after surgery. Blood samples were collected 45 minutes before premedication and 4, 8, 12, 24, 36, 48, 72, 96, and 120 hours after the end of OVH; samples were used for measurement of total WBC and neutrophil counts and concentrations of C-reactive protein (CRP), ceruloplasmin, and fibrinogen. Values did not differ significantly among groups for WBC and neutrophil counts, serum concentrations of CRP and ceruloplasmin, and plasma concentrations of fibrinogen. Concentrations of all inflammatory markers, except serum ceruloplasmin, increased significantly following OVH, but in a similar manner for each group. No significant changes were detected in serum ceruloplasmin concentrations over time. Perioperative administration of both carprofen and meloxicam did not significantly affect the concentrations of CRP, ceruloplasmin, and fibrinogen in dogs undergoing OVH. Thus, use of carprofen or meloxicam should not affect clinical interpretation of results for these 3 acute-phase proteins.

Postoperative outcomes in patients with a do-not-resuscitate (DNR) order undergoing elective procedures.

PubMed

Brovman, Ethan Y; Walsh, Elisa C; Burton, Brittany N; Kuo, Christine E; Lindvall, Charlotta; Gabriel, Rodney A; Urman, Richard D

2018-05-18

Do-not-resuscitate (DNR) status has been shown to be an independent risk factor for mortality in the post-operative period. Patients with DNR orders often undergo elective surgeries to alleviate symptoms and improve quality of life, but there are limited data on outcomes for informed decision making. Retrospective cohort study. A multi-institutional setting including operating room, postoperative recovery area, inpatient wards, and the intensive care unit. A total of 566 patients with a DNR status and 316,431 patients without a DNR status undergoing elective procedures using the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) from 2012. Patients undergoing elective surgical procedures. We analyzed the risk-adjusted 30-day morbidity and mortality outcomes for the matched DNR and non-DNR cohorts undergoing elective surgeries. DNR patients had significantly increased odds of 30-day mortality (OR 2.51 [1.55-4.05], p < 0.001) compared with non-DNR patients. In the DNR versus non-DNR cohort there was no significant difference in the occurrence of a number of 30-day complications, the rate of resuscitative measures undertaken, including cardiac arrest requiring CPR, reintubation, or return to the OR. The most common complications in both DNR and non-DNR patients undergoing elective procedures were transfusion, urinary tract infection, reoperation, and sepsis. Finally, the DNR patients had a significantly increased total length of hospital stay (7.65 ± 9.55 vs. 6.87 ± 9.21 days, p = 0.002). DNR patients, as compared with non-DNR patients, have increased post-operative mortality but not morbidity, which may arise from unmeasured severity of illness or transition to comfort care in accordance with a patient's wishes. The informed consent process for elective surgeries in this patient population should include a discussion of acceptable operative risk. Copyright © 2018 Elsevier Inc. All rights reserved.

Better Object Recognition and Naming Outcome With MRI-Guided Stereotactic Laser Amygdalohippocampotomy for Temporal Lobe Epilepsy

PubMed Central

Drane, Daniel L.; Loring, David W.; Voets, Natalie L.; Price, Michele; Ojemann, Jeffrey G.; Willie, Jon T.; Saindane, Amit M.; Phatak, Vaishali; Ivanisevic, Mirjana; Millis, Scott; Helmers, Sandra L.; Miller, John W.; Meador, Kimford J.; Gross, Robert E.

2015-01-01

SUMMARY OBJECTIVES Temporal lobe epilepsy (TLE) patients experience significant deficits in category-related object recognition and naming following standard surgical approaches. These deficits may result from a decoupling of core processing modules (e.g., language, visual processing, semantic memory), due to “collateral damage” to temporal regions outside the hippocampus following open surgical approaches. We predicted stereotactic laser amygdalohippocampotomy (SLAH) would minimize such deficits because it preserves white matter pathways and neocortical regions critical for these cognitive processes. METHODS Tests of naming and recognition of common nouns (Boston Naming Test) and famous persons were compared with nonparametric analyses using exact tests between a group of nineteen patients with medically-intractable mesial TLE undergoing SLAH (10 dominant, 9 nondominant), and a comparable series of TLE patients undergoing standard surgical approaches (n=39) using a prospective, non-randomized, non-blinded, parallel group design. RESULTS Performance declines were significantly greater for the dominant TLE patients undergoing open resection versus SLAH for naming famous faces and common nouns (F=24.3, p<.0001, η2=.57, & F=11.2, p<.001, η2=.39, respectively), and for the nondominant TLE patients undergoing open resection versus SLAH for recognizing famous faces (F=3.9, p<.02, η2=.19). When examined on an individual subject basis, no SLAH patients experienced any performance declines on these measures. In contrast, 32 of the 39 undergoing standard surgical approaches declined on one or more measures for both object types (p<.001, Fisher’s exact test). Twenty-one of 22 left (dominant) TLE patients declined on one or both naming tasks after open resection, while 11 of 17 right (non-dominant) TLE patients declined on face recognition. SIGNIFICANCE Preliminary results suggest 1) naming and recognition functions can be spared in TLE patients undergoing SLAH, and 2) the hippocampus does not appear to be an essential component of neural networks underlying name retrieval or recognition of common objects or famous faces. PMID:25489630

Retrospective Review of the Anaesthetic Management of Maxillectomies and Mandibulectomies for Benign Tumours in Sub-Saharan Africa.

PubMed

White, Michelle C; Horner, Katherine C; Lai, Peggy S

2016-01-01

Safe anaesthesia is a crucial component of safe surgical care, yet anaesthetic complications are common in resource-limited settings. We describe differences in anaesthetic needs for Mandibulectomy vs. Maxillectomy in three sub-Saharan African countries. Retrospective review of patients undergoing minor Mandibulectomy, major Mandibulectomy, or Maxillectomy in Togo, Guinea and Republic of the Congo. Surgeries were performed on the Africa Mercy, an international non-governmental hospital ship. Primary outcomes were need for advanced airway management and intra-operative blood loss. Secondary outcomes were time under general anaesthesia and hospital length of stay. Multivariate regression determined the association between operation type and each outcome measure. 105 patients were included (25 minor Mandibulectomy, 58 major Mandibulectomy, 22 Maxillectomy procedures). In-hospital mortality was 0%. 44/105 (41.9%) required an advanced airway management technique to achieve intubation, although in all cases this was anticipated prior to the procedure; no differences were noted between surgical procedure (p = 0.72). Operative procedure was a significant risk factor for intra-operative blood loss. Patients undergoing Maxillectomy lost on average 851.5 (413.3, 1289.8, p = 0.0003) mL more blood than patients undergoing minor Mandibulectomy, and 507.3 (150.3, 864.3, p = 0.007) mL more blood than patients undergoing major Mandibulectomy. Patients undergoing Maxillectomy had a significantly higher time under general anaesthesia than those undergoing minor Mandibulectomy. There was no significant difference in hospital length of stay between operation type. Anaesthetic considerations for minor Mandibulectomy, major Mandibulectomy, and Maxillectomy differ with respect to intra-operative blood loss and time under general anaesthesia, but not need for advanced airway management or length of stay. Although advanced airway management was required in 41.9% of patients, there were no unanticipated difficult airways. With appropriate training and resources, safe anaesthesia can be delivered to patients from low-income countries requiring major head and neck surgery.

Retrospective Review of the Anaesthetic Management of Maxillectomies and Mandibulectomies for Benign Tumours in Sub-Saharan Africa

PubMed Central

White, Michelle C.; Horner, Katherine C.; Lai, Peggy S.

2016-01-01

Background Safe anaesthesia is a crucial component of safe surgical care, yet anaesthetic complications are common in resource-limited settings. We describe differences in anaesthetic needs for Mandibulectomy vs. Maxillectomy in three sub-Saharan African countries. Materials and Methods Retrospective review of patients undergoing minor Mandibulectomy, major Mandibulectomy, or Maxillectomy in Togo, Guinea and Republic of the Congo. Surgeries were performed on the Africa Mercy, an international non-governmental hospital ship. Primary outcomes were need for advanced airway management and intra-operative blood loss. Secondary outcomes were time under general anaesthesia and hospital length of stay. Multivariate regression determined the association between operation type and each outcome measure. Results 105 patients were included (25 minor Mandibulectomy, 58 major Mandibulectomy, 22 Maxillectomy procedures). In-hospital mortality was 0%. 44/105 (41.9%) required an advanced airway management technique to achieve intubation, although in all cases this was anticipated prior to the procedure; no differences were noted between surgical procedure (p = 0.72). Operative procedure was a significant risk factor for intra-operative blood loss. Patients undergoing Maxillectomy lost on average 851.5 (413.3, 1289.8, p = 0.0003) mL more blood than patients undergoing minor Mandibulectomy, and 507.3 (150.3, 864.3, p = 0.007) mL more blood than patients undergoing major Mandibulectomy. Patients undergoing Maxillectomy had a significantly higher time under general anaesthesia than those undergoing minor Mandibulectomy. There was no significant difference in hospital length of stay between operation type. Conclusion Anaesthetic considerations for minor Mandibulectomy, major Mandibulectomy, and Maxillectomy differ with respect to intra-operative blood loss and time under general anaesthesia, but not need for advanced airway management or length of stay. Although advanced airway management was required in 41.9% of patients, there were no unanticipated difficult airways. With appropriate training and resources, safe anaesthesia can be delivered to patients from low-income countries requiring major head and neck surgery. PMID:27788172

Detecting cell death with optical coherence tomography and envelope statistics

NASA Astrophysics Data System (ADS)

Farhat, Golnaz; Yang, Victor X. D.; Czarnota, Gregory J.; Kolios, Michael C.

2011-02-01

Currently no standard clinical or preclinical noninvasive method exists to monitor cell death based on morphological changes at the cellular level. In our past work we have demonstrated that quantitative high frequency ultrasound imaging can detect cell death in vitro and in vivo. In this study we apply quantitative methods previously used with high frequency ultrasound to optical coherence tomography (OCT) to detect cell death. The ultimate goal of this work is to use these methods for optically-based clinical and preclinical cancer treatment monitoring. Optical coherence tomography data were acquired from acute myeloid leukemia cells undergoing three modes of cell death. Significant increases in integrated backscatter were observed for cells undergoing apoptosis and mitotic arrest, while necrotic cells induced a decrease. These changes appear to be linked to structural changes observed in histology obtained from the cell samples. Signal envelope statistics were analyzed from fittings of the generalized gamma distribution to histograms of envelope intensities. The parameters from this distribution demonstrated sensitivities to morphological changes in the cell samples. These results indicate that OCT integrated backscatter and first order envelope statistics can be used to detect and potentially differentiate between modes of cell death in vitro.

TransCut: interactive rendering of translucent cutouts.

PubMed

Li, Dongping; Sun, Xin; Ren, Zhong; Lin, Stephen; Tong, Yiying; Guo, Baining; Zhou, Kun

2013-03-01

We present TransCut, a technique for interactive rendering of translucent objects undergoing fracturing and cutting operations. As the object is fractured or cut open, the user can directly examine and intuitively understand the complex translucent interior, as well as edit material properties through painting on cross sections and recombining the broken pieces—all with immediate and realistic visual feedback. This new mode of interaction with translucent volumes is made possible with two technical contributions. The first is a novel solver for the diffusion equation (DE) over a tetrahedral mesh that produces high-quality results comparable to the state-of-art finite element method (FEM) of Arbree et al. but at substantially higher speeds. This accuracy and efficiency is obtained by computing the discrete divergences of the diffusion equation and constructing the DE matrix using analytic formulas derived for linear finite elements. The second contribution is a multiresolution algorithm to significantly accelerate our DE solver while adapting to the frequent changes in topological structure of dynamic objects. The entire multiresolution DE solver is highly parallel and easily implemented on the GPU. We believe TransCut provides a novel visual effect for heterogeneous translucent objects undergoing fracturing and cutting operations.

Radiological features for the approach in trans-sphenoidal pituitary surgery.

PubMed

Twigg, Victoria; Carr, Simon D; Balakumar, Ramkishan; Sinha, Saurabh; Mirza, Showkat

2017-08-01

In order to perform trans-sphenoidal endoscopic pituitary surgery safely and efficiently it is important to identify anatomical and pituitary disease features on the pre-operative CT and MRI scans; thereby minimising the risk to surrounding structures and optimising outcomes. We aim to create a checklist to streamline pre-operative planning. We retrospectively reviewed pre-operative CT and MRI scans of 100 adults undergoing trans-sphenoidal endoscopic pituitary surgery. Radiological findings and their incidence included deviated nasal septum (62%), concha bullosa (32%), bony dehiscence of the carotid arteries (18%), sphenoid septation overlying the internal carotid artery (24% at the sella) and low lying CSF (32%). The mean distance of the sphenoid ostium to the skull base was 10 mm (range 2.7-17.6 mm). We also describe the 'teddy bear' sign which when present on an axial CT indicates the carotid arteries will be identifiable intra-operatively. There are significant variations in the anatomical and pituitary disease features between patients. We describe a number of features on pre-operative scans and have devised a checklist including a new 'teddy bear' sign to aid the surgeon in the anatomical assessment of patients undergoing trans-sphenoidal pituitary surgery.

Epilepsy surgery in patients with malformations of cortical development.

PubMed

Lüders, Hans; Schuele, Stephan U

2006-04-01

Patients with malformations of cortical development often suffer from intractable focal epilepsy. This review considers recent progress in the selection and seizure outcome of patients undergoing resective epilepsy surgery for this condition. Patients with malformations of cortical development restricted to part or even a whole hemisphere may be candidates for epilepsy surgery even when, due to microscopic malformations, magnetic resonance imaging shows no detectable lesion. Despite recent advances in structural and functional imaging, the majority of patients with this condition undergo invasive evaluation. Patients with focal cortical dysplasia, with and without a detectable lesion on magnetic resonance imaging, often have a favorable outcome with epilepsy surgery. The underlying pathological substrate seems to be a better predictor for surgical outcome in patients with focal cortical dysplasia than the presence of a lesion on magnetic resonance imaging. Epilepsy surgery can be offered in a highly selected subgroup of patients with unilateral nodular heterotopia. Seizures in hemimegalencephaly may respond favorably to hemispherectomy, although most children will continue to have seizures and significant functional impairments. Patients with focal epilepsy due to malformations of cortical development are often intractable to medical management. Resective epilepsy surgery can be beneficial, particularly for patients with focal cortical dysplasia and unilateral hemispheric malformations.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Satish, Rohit; Lim, Kipil; Bucher, Nicolas

Lithium rich layered materials are an interesting class of materials which exploit both anionic and cationic redox reactions to store energy upwards of 250 mA h g –1. This paper aims to understand the nature of the redox reactions taking place in these compounds. Li 2RuO 3 was used as the base compound, which is then compared with compounds generated by partially substituting Ru with Ti and Fe respectively. Electrochemical tests indicate that Fe substitution in the sample leads to an improvement in capacity, cycle life and reduction of potential decay. To elucidate the reason for this improvement in operandomore » diffraction experiments were carried out, highlighting the formation of a secondary de-lithiated phase. The distortion of the pristine structure eventually induces frontier orbital reorganization leading to the oxygen redox reaction resulting in extra capacity. Local changes at Fe and Ru ions are recorded using in operando X-ray absorption spectroscopy (XAS). It was noted that while Ru undergoes a reversible redox reaction, Fe undergoes a significant irreversible change in its coordination environment during cycling. In conclusion, the changes in the coordination environment of oxygen and formation of O 2 n– type species were probed in situ using soft X-rays.« less

Relationship of postprandial nonesterified fatty acids, adipokines, and insulin across gender in human immunodeficiency virus-positive patients undergoing highly active antiretroviral therapy.

PubMed

Lu, Guijing; Thomas-Geevarghese, Asha; Anuurad, Erdembileg; Raghavan, Subhashree; Minolfo, Robert; Ormsby, Bernard; Karmally, Wahida; El-Sadr, Wafaa M; Albu, Jeanine; Berglund, Lars

2009-06-01

Metabolic derangements are common in human immunodeficiency virus (HIV)-positive subjects undergoing antiretroviral therapy, but little is known about postprandial conditions. We investigated the relationship between leptin, adiponectin, nonesterified fatty acids (NEFA), and insulin in response to a day-long meal pattern and evaluated gender differences in HIV-positive men (n = 12) and women (n = 13) undergoing highly active antiretroviral therapy (HAART). For both men and women, a significant decrease in postprandial NEFA levels was observed following breakfast (0.53 vs. 0.22 mmol/L, P < 0.001, baseline and at 3 hours, respectively), whereas day-long postprandial leptin and adiponectin levels showed small nonsignificant oscillations. In contrast to NEFA and adiponectin, postprandial leptin levels were significantly higher among women compared to men (P < 0.05). Postprandial NEFA levels correlated positively with fasting insulin levels (r(2) = 0.25, P = 0.016), and the postbreakfast decrease in NEFA levels correlated significantly with the postbreakfast increase in insulin levels (r(2) = 0.17, P = 0.038). No significant association between postprandial adipokines and insulin was observed. In HAART-treated, HIV-infected men and women, levels of NEFA, but not adipokines, showed significant postprandial variation. Furthermore, food intake resulted in significant NEFA suppression in proportion to the food-stimulated insulin increase.

Ultratrace Detection of Nitroaromatics: Picric Acid Responsive Aggregation/Disaggregation of Self-Assembled p-Terphenylbenzimidazolium-Based Molecular Baskets.

PubMed

Sandhu, Sana; Kumar, Rahul; Singh, Prabhpreet; Mahajan, Aman; Kaur, Manmeet; Kumar, Subodh

2015-05-20

1-(p-Terphenyl)-benzimidazolium (TRIPOD-TP) molecules undergo self-assembly to form rodlike structures in aqueous medium, as shown by field-emission scanning electron microscopy, transmission electron microscopy, and dynamic light scattering studies. Upon gradual addition of picric acid (PA), these aggregates undergo an aggregation/disaggregation process to complex morphological structures (10(-12)-10(-10) M PA) and spherical aggregates (10(-9)-10(-8) M PA). These spherical aggregates undergo further dissolution to well-dispersed spheres between 10(-7)-10(-6) M PA. During fluorescence studies, these aggregates demonstrate superamplified fluorescence quenching (>97%) in the presence of 10(-5) to 0.2 equiv of the probe concentration, an unprecedented process with PA. The lowest detection limits by solution of TRIPOD-TP are 5 × 10(-13) PA, 50 × 10(-12) M 2,4-dinitrophenol, 200 × 10(-12) M 2,4,6-trinitrotoluene, and 1 nM 1-chloro-2,4-dinitrobenzene. Paper strips dipped in the solution of TRIPOD-TP demonstrate quantitative fluorescence quenching between 10(-17) and 10(-6) M PA using front-surface steady state studies and can measure as low as 2.29 × 10(-20) g/cm(2) PA.

Structure, phase transitions, and isotope effects in [(CH3)4N]2PuCl6

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilson, Richard E.

2015-11-02

The single crystal X-ray diffraction structure of [(CH3)4N]2PuCl6 is presented for the first time, resolving long standing confusion and speculation regarding the structure of this compound in the literature. A temperature dependent study of this compound shows that the structure of [(CH3)4N]2PuCl6 undergoes no fewer than two phase transitions between 100 and 360 K. The phase of [(CH3)4N]2PuCl6 at room temperature is Fd-3c a = 26.012(3) Å. At 360 K, the structure is in space group Fm-3m with a = 13.088(1) Å. The plutonium octahedra and tetramethylammonium cations undergo a rotative displacement and the degree of rotation varies with temperature,more » giving rise to the phase transition from Fm-3m to Fd-3c as the crystal is cooled. Synthesis and structural studies of the deuterated salt [(CD3)4N]2PuCl6 suggest that there is an isotopic effect associated with this phase transition as revealed by a changing transition temperature in the deuterated versus protonated compound indicating that the donor-acceptor interactions between the tetramethylammonium cations and the hexachloroplutonate anions are driving the phase transformation.« less

Real-time observation of fluctuations in a driven-dissipative quantum many-body system undergoing a phase transition

NASA Astrophysics Data System (ADS)

Donner, Tobias

2015-03-01

A Bose-Einstein condensate whose motional degrees of freedom are coupled to a high-finesse optical cavity via a transverse pump beam constitutes a dissipative quantum many-body system with long range interactions. These interactions can induce a structural phase transition from a flat to a density-modulated state. The transverse pump field simultaneously represents a probe of the atomic density via cavity- enhanced Bragg scattering. By spectrally analyzing the light field leaking out of the cavity, we measure non-destructively the dynamic structure factor of the fluctuating atomic density while the system undergoes the phase transition. An observed asymmetry in the dynamic structure factor is attributed to the coupling to dissipative baths. Critical exponents for both sides of the phase transition can be extracted from the data. We further discuss our progress in adding strong short-range interactions to this system, in order to explore Bose-Hubbard physics with cavity-mediated long-range interactions and self-organization in lower dimensions.

Microbial communities of the Lemon Creek Glacier show subtle structural variation yet stable phylogenetic composition over space and time

PubMed Central

Sheik, Cody S.; Stevenson, Emily I.; Den Uyl, Paul A.; Arendt, Carli A.; Aciego, Sarah M.; Dick, Gregory J.

2015-01-01

Glaciers are geologically important yet transient ecosystems that support diverse, biogeochemically significant microbial communities. During the melt season glaciers undergo dramatic physical, geochemical, and biological changes that exert great influence on downstream biogeochemical cycles. Thus, we sought to understand the temporal melt-season dynamics of microbial communities and associated geochemistry at the terminus of Lemon Creek Glacier (LCG) in coastal southern Alaska. Due to late season snowfall, sampling of LCG occurred in three interconnected areas: proglacial Lake Thomas, the lower glacial outflow stream, and the glacier’s terminus. LCG associated microbial communities were phylogenetically diverse and varied by sampling location. However, Betaproteobacteria, Alphaproteobacteria, and Bacteroidetes dominated communities at all sampling locations. Strict anaerobic groups such as methanogens, SR1, and OP11 were also recovered from glacier outflows, indicating anoxic conditions in at least some portions of the LCG subglacial environment. Microbial community structure was significantly correlated with sampling location and sodium concentrations. Microbial communities sampled from terminus outflow waters exhibited day-to-day fluctuation in taxonomy and phylogenetic similarity. However, these communities were not significantly different from randomly constructed communities from all three sites. These results indicate that glacial outflows share a large proportion of phylogenetic overlap with downstream environments and that the observed significant shifts in community structure are driven by changes in relative abundance of different taxa, and not complete restructuring of communities. We conclude that LCG glacial discharge hosts a diverse and relatively stable microbiome that shifts at fine taxonomic scales in response to geochemistry and likely water residence time. PMID:26042114

Dynamical transitions of a driven Ising interface

NASA Astrophysics Data System (ADS)

Sahai, Manish K.; Sengupta, Surajit

2008-03-01

We study the structure of an interface in a three-dimensional Ising system created by an external nonuniform field H(r,t) . H changes sign over a two-dimensional plane of arbitrary orientation. When the field is pulled with velocity ve , [i.e., H(r,t)=H(r-vet) ], the interface undergoes several dynamical transitions. For low velocities it is pinned by the field profile and moves along with it, the distribution of local slopes undergoing a series of commensurate-incommensurate transitions. For large ve the interface depins and grows with Kardar-Parisi-Zhang exponents.

A novel protocol for antibiotic prophylaxis based on preoperative kidney function in patients undergoing open heart surgery under cardiopulmonary bypass.

PubMed

Odaka, Mizuho; Minakata, Kenji; Toyokuni, Hideaki; Yamazaki, Kazuhiro; Yonezawa, Atsushi; Sakata, Ryuzo; Matsubara, Kazuo

2015-08-01

This study aimed to develop and assess the effectiveness of a protocol for antibiotic prophylaxis based on preoperative kidney function in patients undergoing open heart surgery. We established a protocol for antibiotic prophylaxis based on preoperative kidney function in patients undergoing open heart surgery. This novel protocol was assessed by comparing patients undergoing open heart surgery before (control group; n = 30) and after its implementation (protocol group; n = 31) at Kyoto University Hospital between July 2012 and January 2013. Surgical site infections (SSIs) were observed in 4 control group patients (13.3 %), whereas no SSIs were observed in the protocol group patients (P < 0.05). The total duration of antibiotic use decreased significantly from 80.7 ± 17.6 h (mean ± SD) in the control group to 55.5 ± 14.9 h in the protocol group (P < 0.05). Similarly, introduction of the protocol significantly decreased the total antibiotic dose used in the perioperative period (P < 0.05). Furthermore, antibiotic regimens were changed under suspicion of infection in 5 of 30 control group patients, whereas none of the protocol group patients required this additional change in the antibiotic regimen (P < 0.05). Our novel antibiotic prophylaxis protocol based on preoperative kidney function effectively prevents SSIs in patients undergoing open heart surgery.

Structural studies of Saccharomyces cerevesiae mitochondrial NADP-dependent isocitrate dehydrogenase in different enzymatic states reveal substantial conformational changes during the catalytic reaction.

PubMed

Peng, Yingjie; Zhong, Chen; Huang, Wei; Ding, Jianping

2008-09-01

Isocitrate dehydrogenases (IDHs) catalyze oxidative decarboxylation of isocitrate (ICT) into alpha-ketoglutarate (AKG). We report here the crystal structures of Saccharomyces cerevesiae mitochondrial NADP-IDH Idp1p in binary complexes with coenzyme NADP, or substrate ICT, or product AKG, and in a quaternary complex with NADPH, AKG, and Ca(2+), which represent different enzymatic states during the catalytic reaction. Analyses of these structures identify key residues involved in the binding of these ligands. Comparisons among these structures and with the previously reported structures of other NADP-IDHs reveal that eukaryotic NADP-IDHs undergo substantial conformational changes during the catalytic reaction. Binding or release of the ligands can cause significant conformational changes of the structural elements composing the active site, leading to rotation of the large domain relative to the small and clasp domains along two hinge regions (residues 118-124 and residues 284-287) while maintaining the integrity of its secondary structural elements, and thus, formation of at least three distinct overall conformations. Specifically, the enzyme adopts an open conformation when bound to NADP, a quasi-closed conformation when bound to ICT or AKG, and a fully closed conformation when bound to NADP, ICT, and Ca(2+) in the pseudo-Michaelis complex or with NADPH, AKG, and Ca(2+) in the product state. The conformational changes of eukaryotic NADP-IDHs are quite different from those of Escherichia coli NADP-IDH, for which significant conformational changes are observed only between two forms of the apo enzyme, suggesting that the catalytic mechanism of eukaryotic NADP-IDHs is more complex than that of EcIDH, and involves more fine-tuned conformational changes.

Verbal memory after temporal lobe epilepsy surgery in children: Do only mesial structures matter?

PubMed

Law, Nicole; Benifla, Mony; Rutka, James; Smith, Mary Lou

2017-02-01

Previous findings have been mixed regarding verbal memory outcome after left temporal lobectomy in children, and there are few studies comparing verbal memory change after lateral versus mesial temporal lobe resections. We compared verbal memory outcome associated with sparing or including the mesial structures in children who underwent left or right temporal lobe resection. We also investigated predictors of postsurgical verbal memory change. We retrospectively assessed verbal memory change approximately 1 year after unilateral temporal lobe epilepsy surgery using a list learning task. Participants included 23 children who underwent temporal lobe surgery with sparing of the mesial structures (13 left), and 40 children who had a temporal lobectomy that included resection of mesial structures (22 left). Children who underwent resection from the left lateral and mesial temporal lobe were the only group to show decline in verbal memory. Furthermore, when we considered language representation in the left temporal resection group, patients with left language representation and spared mesial structures showed essentially no change in verbal memory from preoperative to follow-up, whereas those with left language representation and excised mesial structures showed a decline. Postoperative seizure status had no effect on verbal memory change in children after left temporal lobe surgery. Finally, we found that patients with intact preoperative verbal memory experienced a significant decline compared to those with below average preoperative verbal memory. Our findings provide evidence of significant risk factors for verbal memory decline in children, specific to left mesial temporal lobe epilepsy. Children who undergo left temporal lobe surgery that includes mesial structures may be most vulnerable for verbal memory decline, especially when language representation is localized to the left hemisphere and when preoperative verbal memory is intact. Wiley Periodicals, Inc. © 2016 International League Against Epilepsy.

Analysis of Physicochemical and Structural Properties Determining HIV-1 Coreceptor Usage

PubMed Central

Bozek, Katarzyna; Lengauer, Thomas; Sierra, Saleta; Kaiser, Rolf; Domingues, Francisco S.

2013-01-01

The relationship of HIV tropism with disease progression and the recent development of CCR5-blocking drugs underscore the importance of monitoring virus coreceptor usage. As an alternative to costly phenotypic assays, computational methods aim at predicting virus tropism based on the sequence and structure of the V3 loop of the virus gp120 protein. Here we present a numerical descriptor of the V3 loop encoding its physicochemical and structural properties. The descriptor allows for structure-based prediction of HIV tropism and identification of properties of the V3 loop that are crucial for coreceptor usage. Use of the proposed descriptor for prediction results in a statistically significant improvement over the prediction based solely on V3 sequence with 3 percentage points improvement in AUC and 7 percentage points in sensitivity at the specificity of the 11/25 rule (95%). We additionally assessed the predictive power of the new method on clinically derived ‘bulk’ sequence data and obtained a statistically significant improvement in AUC of 3 percentage points over sequence-based prediction. Furthermore, we demonstrated the capacity of our method to predict therapy outcome by applying it to 53 samples from patients undergoing Maraviroc therapy. The analysis of structural features of the loop informative of tropism indicates the importance of two loop regions and their physicochemical properties. The regions are located on opposite strands of the loop stem and the respective features are predominantly charge-, hydrophobicity- and structure-related. These regions are in close proximity in the bound conformation of the loop potentially forming a site determinant for the coreceptor binding. The method is available via server under http://structure.bioinf.mpi-inf.mpg.de/. PMID:23555214

Structural studies of Saccharomyces cerevesiae mitochondrial NADP-dependent isocitrate dehydrogenase in different enzymatic states reveal substantial conformational changes during the catalytic reaction

PubMed Central

Peng, Yingjie; Zhong, Chen; Huang, Wei; Ding, Jianping

2008-01-01

Isocitrate dehydrogenases (IDHs) catalyze oxidative decarboxylation of isocitrate (ICT) into α-ketoglutarate (AKG). We report here the crystal structures of Saccharomyces cerevesiae mitochondrial NADP-IDH Idp1p in binary complexes with coenzyme NADP, or substrate ICT, or product AKG, and in a quaternary complex with NADPH, AKG, and Ca2+, which represent different enzymatic states during the catalytic reaction. Analyses of these structures identify key residues involved in the binding of these ligands. Comparisons among these structures and with the previously reported structures of other NADP-IDHs reveal that eukaryotic NADP-IDHs undergo substantial conformational changes during the catalytic reaction. Binding or release of the ligands can cause significant conformational changes of the structural elements composing the active site, leading to rotation of the large domain relative to the small and clasp domains along two hinge regions (residues 118–124 and residues 284–287) while maintaining the integrity of its secondary structural elements, and thus, formation of at least three distinct overall conformations. Specifically, the enzyme adopts an open conformation when bound to NADP, a quasi-closed conformation when bound to ICT or AKG, and a fully closed conformation when bound to NADP, ICT, and Ca2+ in the pseudo-Michaelis complex or with NADPH, AKG, and Ca2+ in the product state. The conformational changes of eukaryotic NADP-IDHs are quite different from those of Escherichia coli NADP-IDH, for which significant conformational changes are observed only between two forms of the apo enzyme, suggesting that the catalytic mechanism of eukaryotic NADP-IDHs is more complex than that of EcIDH, and involves more fine-tuned conformational changes. PMID:18552125

Atorvastatin can ameliorate left atrial stunning induced by radiofrequency ablation for atrial fibrillation.

PubMed

Xie, Ruiqin; Yang, Yingtao; Cui, Wei; Yin, Hongning; Zheng, Hongmei; Zhang, Jidong; You, Ling

2017-09-01

The objective of this study was to study the functional changes of the left atrium after radiofrequency ablation treatment for atrial fibrillation and the therapeutic effect of atorvastatin. Fifty-eight patients undergoing radiofrequency ablation for atrial fibrillation were randomly divided into non-atorvastatin group and atorvastatin group. Patients in the atorvastatin group were treated with atorvastatin 20 mg p.o. per night in addition to the conventional treatment of atrial fibrillation; patients in the non-atorvastatin group received conventional treatment of atrial fibrillation only. Echocardiography was performed before radiofrequency ablation operation and 1 week, 2 weeks, 3 weeks, and 4 weeks after operation. Two-dimensional ultrasound speckle tracking imaging system was used to measure the structural indexes of the left atrium. Results indicated that there was no significant change for indexes representing the structural status of the left atrium within a month after radiofrequency ablation (P > 0.05); however, there were significant changes for indexes representing the functional status of the left atrium. There were also significant changes in indexes reflecting left atrial strain status: the S and SRs of atorvastatin group were higher than those of non-atorvastatin group (P < 0.05). In summary, atorvastatin could improve left atrial function and shorten the duration of atrial stunning after radiofrequency ablation of atrial fibrillation.

Detection of Theileria parva in tissues of cattle undergoing severe East Coast fever disease show significant parasite DNA accumulation in the spleen.

PubMed

Olds, Cassandra L; Paul, Tasha; Scoles, Glen A

2016-12-15

Infiltration and proliferation of Theileria parva infected lymphocytes in bovine host lymphoid organs is one of the hallmarks of T. parva infection. The relative abundance of parasites within infected host tissues, both lymphoid and non-lymphoid is however unknown. Using quantitative PCR, we have shown that significantly higher concentrations of T. parva DNA are detected in the spleens of cattle undergoing severe disease compared to other organs. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Orion Crew Module Adapter-Structural Test Article and European S

NASA Image and Video Library

2017-05-09

Inside the Neil Armstrong Operations and Checkout Building high bay at NASA's Kennedy Space Center in Florida, operations are underway to lower the Orion crew module adapter structural test article onto the European Space Agency's service module structural test article. After the hardware is attached, the structure will be packed and shipped to Lockheed Martin's Denver facility to undergo testing. The Orion spacecraft will launch atop the agency's Space Launch System rocket on Exploration Mission-1 in 2019.

Liver enzymes in patients with chronic kidney disease undergoing peritoneal dialysis and hemodialysis.

PubMed

Liberato, Isabella Ramos de Oliveira; Lopes, Edmundo Pessoa de Almeida; Cavalcante, Maria Alina Gomes de Mattos; Pinto, Tiago Costa; Moura, Izolda Fernades; Loureiro Júnior, Luiz

2012-01-01

The present study was designed to analyze the serum levels of aspartate and alanine aminotransferases, gamma-glutamyl transferase, and the hematocrit in patients with chronic kidney disease who were undergoing peritoneal dialysis or hemodialysis. Twenty patients on peritoneal dialysis and 40 on hemodialysis were assessed, and the patients were matched according to the length of time that they had been on dialysis. Blood samples were collected (both before and after the session for those on hemodialysis) to measure the enzymes and the hematocrit. In the samples from the patients who were undergoing peritoneal dialysis, the aspartate and alanine aminotransferase levels were slightly higher compared with the samples collected from the patients before the hemodialysis session and slightly lower compared with the samples collected after the hemodialysis session. The levels of gamma-glutamyl transferase in the hemodialysis patients were slightly higher than the levels in the patients who were undergoing peritoneal dialysis. In addition, the levels of aminotransferases and gamma-glutamyl transferase that were collected before the hemodialysis session were significantly lower than the values collected after the session. The hematocrit levels were significantly lower in the patients who were on peritoneal dialysis compared with the patients on hemodialysis (both before and after the hemodialysis session), and the levels were also significantly lower before hemodialysis compared with after hemodialysis. The aminotransferase levels in the patients who were undergoing peritoneal dialysis were slightly higher compared with the samples collected before the hemodialysis session, whereas the aminotransferase levels were slightly lower compared with the samples collected after the session. The hematocrits and the aminotransferase and gamma-glutamyl transferase levels of the samples collected after the hemodialysis session were significantly higher than the samples collected before the session. Taken together, the present data suggest that hemodilution could alter the serum levels of liver enzymes.

Cooperative structural transitions in amyloid-like aggregation

NASA Astrophysics Data System (ADS)

Steckmann, Timothy; Bhandari, Yuba R.; Chapagain, Prem P.; Gerstman, Bernard S.

2017-04-01

Amyloid fibril aggregation is associated with several horrific diseases such as Alzheimer's, Creutzfeld-Jacob, diabetes, Parkinson's, and others. Although proteins that undergo aggregation vary widely in their primary structure, they all produce a cross-β motif with the proteins in β-strand conformations perpendicular to the fibril axis. The process of amyloid aggregation involves forming myriad different metastable intermediate aggregates. To better understand the molecular basis of the protein structural transitions and aggregation, we report on molecular dynamics (MD) computational studies on the formation of amyloid protofibrillar structures in the small model protein ccβ, which undergoes many of the structural transitions of the larger, naturally occurring amyloid forming proteins. Two different structural transition processes involving hydrogen bonds are observed for aggregation into fibrils: the breaking of intrachain hydrogen bonds to allow β-hairpin proteins to straighten, and the subsequent formation of interchain H-bonds during aggregation into amyloid fibrils. For our MD simulations, we found that the temperature dependence of these two different structural transition processes results in the existence of a temperature window that the ccβ protein experiences during the process of forming protofibrillar structures. This temperature dependence allows us to investigate the dynamics on a molecular level. We report on the thermodynamics and cooperativity of the transformations. The structural transitions that occurred in a specific temperature window for ccβ in our investigations may also occur in other amyloid forming proteins but with biochemical parameters controlling the dynamics rather than temperature.

Stability in a changing world - palm community dynamics in the hyperdiverse western Amazon over 17 years.

PubMed

Olivares, Ingrid; Svenning, Jens-Christian; van Bodegom, Peter M; Valencia, Renato; Balslev, Henrik

2017-03-01

Are the hyperdiverse local forests of the western Amazon undergoing changes linked to global and local drivers such as climate change, or successional dynamics? We analyzed local climatic records to assess potential climatic changes in Yasuní National Park, Ecuador, and compared two censuses (1995, 2012) of a palm community to assess changes in community structure and composition. Over 17 years, the structure and composition of this palm community remained remarkably stable. Soil humidity was significantly lower and canopy conditions were significantly more open in 2012 compared to 1995, but local climatic records showed that no significant changes in precipitation, temperature or river level have occurred during the last decade. Thus, we found no evidence of recent directional shifts in climate or the palm community in Yasuní. The absence of changes in local climate and plant community dynamics in Yasuní contrasts with recent findings from eastern Amazon, where environmental change is driving significant changes in ecosystem dynamics. Our findings suggest that until now, local forests in the northwest Amazon may have escaped pressure from climate change. The stability of this rich palm community embedded in the hyperdiverse Yasuní National Park underlines its uniqueness as a sanctuary for the protection of Amazonian diversity from global change impacts. © 2016 John Wiley & Sons Ltd.

Accumulation of epicardial fat rather than visceral fat is an independent risk factor for left ventricular diastolic dysfunction in patients undergoing peritoneal dialysis.

PubMed

Lin, Heng-Hsu; Lee, Jen-Kuang; Yang, Chung-Yi; Lien, Yu-Chung; Huang, Jenq-Wen; Wu, Cho-Kai

2013-08-30

Symptoms of heart failure with preserved left ventricular systolic function are common among patients undergoing peritoneal dialysis (PD). Epicardial fat (EpF) is an ectopic fat depot with possible paracrine or mechanical effects on myocardial function. The aim of our current study is to assess the association between EpF and Left ventricular diastolic dysfunction (LVDD) in patients undergoing PD and to clarify the relationships among EpF, inflammation, and LVDD in this population. This was a cross-sectional study of 149 patients with preserved left ventricular systolic function who were undergoing PD. LVDD was diagnosed (according to the European Society of Cardiology guidelines) and EpF thickness measured by echocardiography. The patients without LVDD were used as controls. The serum inflammatory biomarker high-sensitivity C-reactive protein (hsCRP) was measured. The location and amount of adipose tissue were assessed by computed tomography (CT) at the level of the fourth lumbar vertebra. Subjects with LVDD had higher levels of hsCRP, more visceral and peritoneal fat, and thicker EpF (all p < 0.001) than controls. Visceral adipose tissue, hsCRP, and EpF all correlated significantly (p < 0.05) with LVDD. Multivariate regression analysis rendered the relationship between visceral adipose tissue and LVDD insignificant, whereas EpF was the most powerful determinant of LVDD (odds ratio = 2.41, 95% confidence interval = 1.43-4.08, p < 0.01). EpF thickness also correlated significantly with the ratio of transmitral Doppler early filling velocity to tissue Doppler early diastolic mitral annular velocity (E/e'; r = 0.27, p < 0.01). EpF thickness is significantly independently associated with LVDD in patients undergoing PD and may be involved in its pathogenesis.

Accumulation of epicardial fat rather than visceral fat is an independent risk factor for left ventricular diastolic dysfunction in patients undergoing peritoneal dialysis

PubMed Central

2013-01-01

Background Symptoms of heart failure with preserved left ventricular systolic function are common among patients undergoing peritoneal dialysis (PD). Epicardial fat (EpF) is an ectopic fat depot with possible paracrine or mechanical effects on myocardial function. The aim of our current study is to assess the association between EpF and Left ventricular diastolic dysfunction (LVDD) in patients undergoing PD and to clarify the relationships among EpF, inflammation, and LVDD in this population. Methods This was a cross-sectional study of 149 patients with preserved left ventricular systolic function who were undergoing PD. LVDD was diagnosed (according to the European Society of Cardiology guidelines) and EpF thickness measured by echocardiography. The patients without LVDD were used as controls. The serum inflammatory biomarker high-sensitivity C-reactive protein (hsCRP) was measured. The location and amount of adipose tissue were assessed by computed tomography (CT) at the level of the fourth lumbar vertebra. Results Subjects with LVDD had higher levels of hsCRP, more visceral and peritoneal fat, and thicker EpF (all p < 0.001) than controls. Visceral adipose tissue, hsCRP, and EpF all correlated significantly (p < 0.05) with LVDD. Multivariate regression analysis rendered the relationship between visceral adipose tissue and LVDD insignificant, whereas EpF was the most powerful determinant of LVDD (odds ratio = 2.41, 95% confidence interval = 1.43–4.08, p < 0.01). EpF thickness also correlated significantly with the ratio of transmitral Doppler early filling velocity to tissue Doppler early diastolic mitral annular velocity (E/e’; r = 0.27, p < 0.01). Conclusion EpF thickness is significantly independently associated with LVDD in patients undergoing PD and may be involved in its pathogenesis. PMID:24001037

Outcomes of Highly Sensitized Patients Undergoing Simultaneous Liver and Kidney Transplantation: A Single-Center Experience With Desensitization.

PubMed

Steggerda, J A; Kang, A; Pan, S-H; Sundaram, V; Nissen, N N; Klein, A S; Todo, T; Annamalai, A; Vo, A; Jordan, S C; Kim, I K

Preformed donor-specific human leukocyte antigen antibodies (DSAs) in patients undergoing simultaneous liver and kidney transplantation (SLKT) are an independent risk factor for poorer patient and renal allograft survival. The outcomes of patients highly sensitized (HS) against HLA antigens undergoing SLKT and select HS SLKT recipients undergoing desensitization at a high-volume desensitization center were investigated. Seventy-five patients undergoing SLKT at a high-volume desensitization center between January 1, 2001, and December 31, 2015, were retrospectively reviewed. HS patients were defined by panel-reactive antibody (PRA) >30% (n = 17 patients), 11 of whom received pre- or perioperative desensitization with high-dose intravenous immunoglobulin (IVIG) ± rituximab. HS patients had significantly higher class I and class II PRA (class I = 41.3% ± 40.0% vs 2.5% ± 6.3%; class II = 45.7% ± 36.4% vs 1.0% ± 2.9%; P < .001), were more likely to be female (P = .05), and more likely to have had a prior transplant (P = .03). HS patients demonstrated greater susceptibility to renal cell-mediated rejection (CMR) (23.5% vs 5.2%, P = .02) compared to nonsensitized patients. Higher renal antibody-mediated rejection (ABMR) was also observed in HS patients, 11.8% vs 3.4%, but did not reach significance (P = .18). Desensitization in select HS SLKT patients was well tolerated but did not improve patient and allograft survival or significantly curtail rejection. HS SLKT recipients demonstrated increased allograft rejection, particularly CMR, but patient and graft survival were not impacted in the first year post-transplant. Select HS SLKT patients tolerated desensitization with high-dose IVIG ± rituximab and may have received additional immunoprotection against ABMR but survival was not affected. Copyright © 2017 Elsevier Inc. All rights reserved.

A pilot randomized trial of pentoxifylline for the reduction of periprocedural myocardial injury in patients undergoing elective percutaneous coronary intervention.

PubMed

Aslanabadi, Naser; Shirzadi, Hamid Reza; Asghari-Soufi, Hossein; Dousti, Samaneh; Ghaffari, Samad; Sohrabi, Bahram; Mashayekhi, Simin Ozar; Hamishehkar, Hadi; Entezari-Maleki, Taher

2015-02-01

Periprocedural myocardial injury (PMI) following percutaneous coronary intervention (PCI) has received great attention due to its significant association with mortality and morbidity. Accordingly, cardioprotection during PCI is one of the important therapeutic concerns. Regarding the potential cardiovascular benefits of pentoxifylline this study was performed to evaluate whether the pretreatment pentoxifylline could reduce PMI in patients who are undergoing elective PCI. A randomized clinical trial on 85 patients undergoing elective PCI was performed. The intervention group (n = 41) received 1200 mg pentoxifylline in divided doses plus the standard treatment before PCI, while the control group (n = 44) received the standard treatment. For assessing myocardial damage during PCI, the levels of CK-MB and troponin-I were measured at baseline, 8, and 24 h after the procedure. Then, patients were followed up for a 1-month period regarding the major adverse cardiac effect. Comparing with the control group, no significant change of CK-MB at 8 (p = 0.315) and 24 h (p = 0.896) after PCI was documented in pentoxifylline group. Similarly, no significant change was found in troponin-I at 8 (p = 0.141) and 24 h (p = 0.256) after PCI. This study could not support the pretreatment with pentoxifylline in the prevention of PMI in patients undergoing elective PCI. However, the trend was toward the potential benefit of pentoxifylline.

[The preparation of a new hydroxyapatite and the study on its cytocompatibility].

PubMed

Tao, Kai; Mao, Tianqiu; Chen, Fulin; Liu, Xiaoyan

2006-08-01

The cuttlebones, harvested from cuttles, undergo the chemical reaction in high temperature and high pressure for a certain time. The products are qualitatively analysed, and spacial structure observation and cytocompatibility are tested. The results show that the chemical component of the cuttlebone is CaCO3 and the crystal type is aragonite. Cuttlebones undergo a hydro-thermal reaction, and thus transform into hydroxyapatite-that is, the cuttlebone-transformed hydroxyapatite(CBHA). The CBHA materials have the interconnected microporous network structures. Under the high magnification, CBHAs appear to have many micro-spheres, thus construct a new self-assembled nano-material system. The marrow stromal osteoblasts can adhere to and proliferate well on the surface of the CBHAs. These results show that CBHAs have good biocompatibility. Therefore, it can be a potential candidate scaffold for bone tissue engineering.

A structural, functional, and computational analysis suggests pore flexibility as the base for the poor selectivity of CNG channels

PubMed Central

Napolitano, Luisa Maria Rosaria; Bisha, Ina; De March, Matteo; Marchesi, Arin; Arcangeletti, Manuel; Demitri, Nicola; Mazzolini, Monica; Rodriguez, Alex; Magistrato, Alessandra; Onesti, Silvia; Laio, Alessandro; Torre, Vincent

2015-01-01

Cyclic nucleotide-gated (CNG) ion channels, despite a significant homology with the highly selective K+ channels, do not discriminate among monovalent alkali cations and are permeable also to several organic cations. We combined electrophysiology, molecular dynamics (MD) simulations, and X-ray crystallography to demonstrate that the pore of CNG channels is highly flexible. When a CNG mimic is crystallized in the presence of a variety of monovalent cations, including Na+, Cs+, and dimethylammonium (DMA+), the side chain of Glu66 in the selectivity filter shows multiple conformations and the diameter of the pore changes significantly. MD simulations indicate that Glu66 and the prolines in the outer vestibule undergo large fluctuations, which are modulated by the ionic species and the voltage. This flexibility underlies the coupling between gating and permeation and the poor ionic selectivity of CNG channels. PMID:26100907

The national hydrologic bench-mark network

USGS Publications Warehouse

Cobb, Ernest D.; Biesecker, J.E.

1971-01-01

The United States is undergoing a dramatic growth of population and demands on its natural resources. The effects are widespread and often produce significant alterations of the environment. The hydrologic bench-mark network was established to provide data on stream basins which are little affected by these changes. The network is made up of selected stream basins which are not expected to be significantly altered by man. Data obtained from these basins can be used to document natural changes in hydrologic characteristics with time, to provide a better understanding of the hydrologic structure of natural basins, and to provide a comparative base for studying the effects of man on the hydrologic environment. There are 57 bench-mark basins in 37 States. These basins are in areas having a wide variety of climate and topography. The bench-mark basins and the types of data collected in the basins are described.

A structural, functional, and computational analysis suggests pore flexibility as the base for the poor selectivity of CNG channels.

PubMed

Napolitano, Luisa Maria Rosaria; Bisha, Ina; De March, Matteo; Marchesi, Arin; Arcangeletti, Manuel; Demitri, Nicola; Mazzolini, Monica; Rodriguez, Alex; Magistrato, Alessandra; Onesti, Silvia; Laio, Alessandro; Torre, Vincent

2015-07-07

Cyclic nucleotide-gated (CNG) ion channels, despite a significant homology with the highly selective K(+) channels, do not discriminate among monovalent alkali cations and are permeable also to several organic cations. We combined electrophysiology, molecular dynamics (MD) simulations, and X-ray crystallography to demonstrate that the pore of CNG channels is highly flexible. When a CNG mimic is crystallized in the presence of a variety of monovalent cations, including Na(+), Cs(+), and dimethylammonium (DMA(+)), the side chain of Glu66 in the selectivity filter shows multiple conformations and the diameter of the pore changes significantly. MD simulations indicate that Glu66 and the prolines in the outer vestibule undergo large fluctuations, which are modulated by the ionic species and the voltage. This flexibility underlies the coupling between gating and permeation and the poor ionic selectivity of CNG channels.

3D printing technology used in severe hip deformity.

PubMed

Wang, Shanshan; Wang, Li; Liu, Yan; Ren, Yongfang; Jiang, Li; Li, Yan; Zhou, Hao; Chen, Jie; Jia, Wenxiao; Li, Hui

2017-09-01

This study was designed to assess the use of a 3D printing technique in total hip arthroplasty (THA) for severe hip deformities, where new and improved approaches are needed. THAs were performed from January 2015 to December 2016. Bioprosthesis artificial hip joints were used in both conventional and 3D printing hip arthroplasties. A total of 74 patients (57 cases undergoing conventional hip replacements and 17 undergoing 3D printing hip replacements) were followed-up for an average of 24 months. The average age of the patients was 62.7 years. Clinical data between the patients treated with different approaches were compared. Results showed that the time to postoperative weight bearing and the Harris scores of the patients in the 3D printing group were better than those for patients in the conventional hip replacement group. Unfortunately, the postoperative infection and loosening rates were higher in the 3D printing group. However, there were no significant differences in femoral neck anteversion, neck shaft, acetabular or sharp angles between ipsilateral and contralateral sides in the 3D printing group (P>0.05). The femoral neck anteversion angle was significantly different between the two sides in the conventional hip replacement group (P<0.05). Based on these results, we suggest that the 3D printing approach provides a better short-term curative effect that is more consistent with the physiological structure and anatomical characteristics of the patient, and we anticipate that its use will help improve the lives of many patients.

Assessment of Physical Therapy Strategies for Recovery of Urinary Continence after Prostatectomy

PubMed Central

Santos, Nivea Adriano de Santana e; Saintrain, Maria Vieira de Lima; Regadas, Rommel Prata; da Silveira, Romulo Augusto; de Menezes, Francisco Julimar Correia

2017-01-01

Introduction: Urinary incontinence is a complication of radical prostatectomy. Pelvic floor exercises can facilitate recovery of continence after surgery; however, there is not sufficient evidence that physical therapy with biofeedback training is effective, particularly with respect to providing a faster recovery. Objective: To analyze the application of physical therapy techniques in the recovery of urinary incontinence after prostatectomy. Methodology: A randomized clinical trial was conducted from April to October 2015 with patients undergoing radical prostatectomy up to three months after surgery at the Santa Casa de Misericordia in Northeastern Brazil. The physical therapy intervention consisted of up to eight individual sessions. Patients were randomized into the intervention group, which performed exercises and received biofeedback training, and the control group, which performed exercises alone. Participants were assessed before, during and after treatment. The initial assessment included a structured instrument addressing sociodemographic and urological data. Frequencies were calculated for all variables and comparisons were checked by the Mann-Whitney test and for correlation significance. Results: The study included 13 patients aged 54-74 years, the majority undergoing retropubic surgery with mild urinary incontinence [11 (84.6%)]. There was a significant difference in the outcome of the pad test before (p=0.070) and after (p=0.015) treatment between the groups, but the reduction of urinary loss and the time to recovery of continence were equivalent for both groups. Conclusion: Both interventions provided improvement in the degree of incontinence within two months of treatment. PMID:28240013

Resilience of networks formed of interdependent modular networks

NASA Astrophysics Data System (ADS)

Shekhtman, Louis M.; Shai, Saray; Havlin, Shlomo

2015-12-01

Many infrastructure networks have a modular structure and are also interdependent with other infrastructures. While significant research has explored the resilience of interdependent networks, there has been no analysis of the effects of modularity. Here we develop a theoretical framework for attacks on interdependent modular networks and support our results through simulations. We focus, for simplicity, on the case where each network has the same number of communities and the dependency links are restricted to be between pairs of communities of different networks. This is particularly realistic for modeling infrastructure across cities. Each city has its own infrastructures and different infrastructures are dependent only within the city. However, each infrastructure is connected within and between cities. For example, a power grid will connect many cities as will a communication network, yet a power station and communication tower that are interdependent will likely be in the same city. It has previously been shown that single networks are very susceptible to the failure of the interconnected nodes (between communities) (Shai et al 2014 arXiv:1404.4748) and that attacks on these nodes are even more crippling than attacks based on betweenness (da Cunha et al 2015 arXiv:1502.00353). In our example of cities these nodes have long range links which are more likely to fail. For both treelike and looplike interdependent modular networks we find distinct regimes depending on the number of modules, m. (i) In the case where there are fewer modules with strong intraconnections, the system first separates into modules in an abrupt first-order transition and then each module undergoes a second percolation transition. (ii) When there are more modules with many interconnections between them, the system undergoes a single transition. Overall, we find that modular structure can significantly influence the type of transitions observed in interdependent networks and should be considered in attempts to make interdependent networks more resilient.

Differential Structural Plasticity of Corticostriatal and Thalamostriatal Axo-Spinous Synapses in MPTP-Treated Parkinsonian Monkeys

PubMed Central

Villalba, Rosa M.; Smith, Yoland

2011-01-01

Striatal spine loss is a key pathological feature of Parkinson's disease (PD). Knowing that striatal glutamatergic afferents target dendritic spines, these data appear difficult to reconcile with evidence for an increased expression of the vesicular glutamate transporter 1 (vGluT1) in the striatum of PD patients and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated monkeys, as well as in some electrophysiological studies showing overactivity of the corticostriatal glutamatergic system in models of parkinsonism. To address the possibility that structural changes in glutamatergic afferents may underlie these discrepancies, we undertook an ultrastructural analysis of vGluT1-positive (i.e., corticostriatal) and vGluT2-positive (i.e., mostly thalamostriatal) axo-spinous glutamatergic synapses using a 3D electron microscopic approach in normal and MPTP-treated monkeys. Three main conclusions can be drawn: 1) spines contacted by vGluT1-containing terminals have larger volume and harbor significantly larger postsynaptic densities (PSDs) than those contacted by vGluT2-immunoreactive boutons; 2) a subset of vGluT2-, but not vGluT1-immunoreactive, terminals display a pattern of multisynaptic connectivity in normal and MPTP-treated monkeys; and 3) VGluT1- and vGluT2-positive axo-spinous synapses undergo ultrastructural changes (larger spine volume, larger PSDs, increased PSD perforations, larger presynaptic terminal) indicative of increased synaptic activity in parkinsonian animals. Furthermore, spines contacted by cortical terminals display an increased volume of their spine apparatus in MPTP-treated monkeys, suggesting an increased protein synthesis at corticostriatal synapses. These findings demonstrate that corticostriatal and thalamostriatal glutamatergic axo-spinous synapses display significantly different ultrastructural features, and that both systems undergo complex morphological changes that could underlie the pathophysiology of corticostriatal and thalamostriatal systems in PD. PMID:21280048

Dehydration-induced amorphous phases of calcium carbonate.

PubMed

Saharay, Moumita; Yazaydin, A Ozgur; Kirkpatrick, R James

2013-03-28

Amorphous calcium carbonate (ACC) is a critical transient phase in the inorganic precipitation of CaCO3 and in biomineralization. The calcium carbonate crystallization pathway is thought to involve dehydration of more hydrated ACC to less hydrated ACC followed by the formation of anhydrous ACC. We present here computational studies of the transition of a hydrated ACC with a H2O/CaCO3 ratio of 1.0 to anhydrous ACC. During dehydration, ACC undergoes reorganization to a more ordered structure with a significant increase in density. The computed density of anhydrous ACC is similar to that of calcite, the stable crystalline phase. Compared to the crystalline CaCO3 phases, calcite, vaterite, and aragonite, the computed local structure of anhydrous ACC is most-similar to those of calcite and vaterite, but the overall structure is not well described by either. The strong hydrogen bond interaction between the carbonate ions and water molecules plays a crucial role in stabilizing the less hydrated ACC compositions compared to the more hydrated ones, leading to a progressively increasing hydration energy with decreasing water content.

Identification of phosphates involved in catalysis by the ribozyme RNase P RNA.

PubMed Central

Harris, M E; Pace, N R

1995-01-01

The RNA subunit of ribonuclease P (RNase P RNA) is a catalytic RNA that cleaves precursor tRNAs to generate mature tRNA 5' ends. Little is known concerning the identity and arrangement of functional groups that constitute the active site of this ribozyme. We have used an RNase P RNA-substrate conjugate that undergoes rapid, accurate, and efficient self-cleavage in vitro to probe, by phosphorothioate modification-interference, functional groups required for catalysis. We identify four phosphate oxygens where substitution by sulfur significantly reduces the catalytic rate (50-200-fold). Interference at one site was partially rescued in the presence of manganese, suggesting a direct involvement in binding divalent metal ion cofactors required for catalysis. All sites are located in conserved sequence and secondary structure, and positioned adjacent to the substrate phosphate in a tertiary structure model of the ribozyme-substrate complex. The spatial arrangement of phosphorothioate-sensitive sites in RNase P RNA was found to resemble the distribution of analogous positions in the secondary and potential tertiary structures of other large catalytic RNAs. PMID:7585250

Calmodulin fishing with a structurally disordered bait triggers CyaA catalysis

PubMed Central

O’Brien, Darragh P.; Durand, Dominique; Voegele, Alexis; Hourdel, Véronique; Davi, Marilyne; Chamot-Rooke, Julia; Vachette, Patrice; Brier, Sébastien; Ladant, Daniel

2017-01-01

Once translocated into the cytosol of target cells, the catalytic domain (AC) of the adenylate cyclase toxin (CyaA), a major virulence factor of Bordetella pertussis, is potently activated by binding calmodulin (CaM) to produce supraphysiological levels of cAMP, inducing cell death. Using a combination of small-angle X-ray scattering (SAXS), hydrogen/deuterium exchange mass spectrometry (HDX-MS), and synchrotron radiation circular dichroism (SR-CD), we show that, in the absence of CaM, AC exhibits significant structural disorder, and a 75-residue-long stretch within AC undergoes a disorder-to-order transition upon CaM binding. Beyond this local folding, CaM binding induces long-range allosteric effects that stabilize the distant catalytic site, whilst preserving catalytic loop flexibility. We propose that the high enzymatic activity of AC is due to a tight balance between the CaM-induced decrease of structural flexibility around the catalytic site and the preservation of catalytic loop flexibility, allowing for fast substrate binding and product release. The CaM-induced dampening of AC conformational disorder is likely relevant to other CaM-activated enzymes. PMID:29287065

Electronic Structure Control of Sub-nanometer 1D SnTe via Nanostructuring within Single-Walled Carbon Nanotubes.

PubMed

Vasylenko, Andrij; Marks, Samuel; Wynn, Jamie M; Medeiros, Paulo V C; Ramasse, Quentin M; Morris, Andrew J; Sloan, Jeremy; Quigley, David

2018-05-25

Nanostructuring, e. g., reduction of dimensionality in materials, offers a viable route toward regulation of materials electronic and hence functional properties. Here, we present the extreme case of nanostructuring, exploiting the capillarity of single-walled carbon nanotubes (SWCNTs) for the synthesis of the smallest possible SnTe nanowires with cross sections as thin as a single atom column. We demonstrate that by choosing the appropriate diameter of a template SWCNT, we can manipulate the structure of the quasi-one-dimensional (1D) SnTe to design electronic behavior. From first principles, we predict the structural re-formations that SnTe undergoes in varying encapsulations and confront the prediction with TEM imagery. To further illustrate the control of physical properties by nanostructuring, we study the evolution of transport properties in a homologous series of models of synthesized and isolated SnTe nanowires varying only in morphology and atomic layer thickness. This extreme scaling is predicted to significantly enhance thermoelectric performance of SnTe, offering a prospect for further experimental studies and future applications.

Topology Synthesis of Structures Using Parameter Relaxation and Geometric Refinement

NASA Technical Reports Server (NTRS)

Hull, P. V.; Tinker, M. L.

2007-01-01

Typically, structural topology optimization problems undergo relaxation of certain design parameters to allow the existence of intermediate variable optimum topologies. Relaxation permits the use of a variety of gradient-based search techniques and has been shown to guarantee the existence of optimal solutions and eliminate mesh dependencies. This Technical Publication (TP) will demonstrate the application of relaxation to a control point discretization of the design workspace for the structural topology optimization process. The control point parameterization with subdivision has been offered as an alternative to the traditional method of discretized finite element design domain. The principle of relaxation demonstrates the increased utility of the control point parameterization. One of the significant results of the relaxation process offered in this TP is that direct manufacturability of the optimized design will be maintained without the need for designer intervention or translation. In addition, it will be shown that relaxation of certain parameters may extend the range of problems that can be addressed; e.g., in permitting limited out-of-plane motion to be included in a path generation problem.

Structural changes of deposited casein micelles induced by membrane filtration.

PubMed

Gebhardt, R; Steinhauer, T; Meyer, P; Sterr, J; Perlich, J; Kulozik, U

2012-01-01

Casein micelles undergo shape changes when subjected to frontal filtration forces. Grazing incidence small angle X-ray scattering (GISAXS) and atomic force microscopy (AFM) allow a quantification of such structural changes on filtration cakes deposited on smooth silicon micro-sieves. A trans-membrane pressure of deltap = 400 mbar across the micro-sieve leads to an immediate film formation after deposition of casein solution. We observe significant changes in the GISAXS pattern depending on how many layers are stacked on top of each other. Compared to a deposit formed by one layer, GISAXS on a deposit formed by three layers of casein micelles leads to less scattering in the vertical and more scattering in the horizontal direction. Simulations show that the experimental results can be interpreted by a structural transformation from an originally spherical micelle shape to an ellipsoidal-deformed shape. The results are supported by AFM measurements showing a reduced lateral size of casein micelles deposited on top of a membrane pore. The observed shape changes could be due to filtration forces acting on densely packed deposits confining the micelles into ellipsoidal shapes.

Associations between ASA Physical Status and postoperative mortality at 48 h: a contemporary dataset analysis compared to a historical cohort.

PubMed

Hopkins, Thomas J; Raghunathan, Karthik; Barbeito, Atilio; Cooter, Mary; Stafford-Smith, Mark; Schroeder, Rebecca; Grichnik, Katherine; Gilbert, Richard; Aronson, Solomon

2016-01-01

In this study, we examined the association between American Society of Anesthesiologists Physical Status (ASA PS) designation and 48-h mortality for both elective and emergent procedures in a large contemporary dataset (patient encounters between 2009 and 2014) and compared this association with data from a landmark study published by Vacanti et al. in 1970. Patient history, hospital characteristics, anesthetic approach, surgical procedure, efficiency and quality indicators, and patient outcomes were prospectively collected for 732,704 consecutive patient encounters between January 1, 2009, and December 31, 2014, at 233 anesthetizing locations across 19 facilities in two US states and stored in the Quantum™ Clinical Navigation System (QCNS) database. The outcome (death within 48 h of procedure) was tabulated against ASA PS designations separately for patients with and without "E" status labels. To maintain consistency with the historical cohort from the landmark study performed by Vacanti et al. on adult men at US naval hospitals in 1970, we then created a comparison cohort in the contemporary dataset that consisted of 242,103 adult male patients (with/without E designations) undergoing elective and emergent procedures. Differences in the relationship between ASA PS and 48-h mortality in the historical and contemporary cohorts were assessed for patients undergoing elective and emergent procedures. As reported nearly five decades ago, we found a significant trend toward increased mortality with increasing ASA PS for patients undergoing both elective and emergent procedures in a large contemporary cohort ( p  < 0.0001). Additionally, the overall mortality rate at 48 h was significantly higher among patients undergoing emergent compared to elective procedures in the large contemporary cohort (1.27 versus 0.03 %, p  < 0.0001). In the comparative analysis with the historical cohort that focused on adult males, we found the overall 48-h mortality rate was significantly lower among patients undergoing elective procedures in the contemporary cohort (0.05 % now versus 0.24 % in 1970, p  < 0.0001) but not significantly lower among those undergoing emergent procedures (1.88 % now versus 1.22 % in 1970, p  < 0.0001). The association between increasing ASA PS designation (1-5) and mortality within 48 h of surgery is significant for patients undergoing both elective and emergent procedures in a contemporary dataset consisting of over 700,000 patient encounters. Emergency surgery was associated with a higher risk of patient death within 48 h of surgery in this contemporary dataset. These data trends are similar to those observed nearly five decades ago in a landmark study evaluating the association between ASA PS and 48-h surgical mortality on adult men at US naval hospitals. When a comparison cohort was created from the contemporary dataset and compared to this landmark historical cohort, the absolute 48-h mortality rate was significantly lower in the contemporary cohort for elective procedures but not significantly lower for emergency procedures. The underlying implications of these findings remain to be determined.

Micronuclei and other nuclear anomalies in normal human buccal mucosa cells of oral cancer patients undergoing radiotherapy: a field effect.

PubMed

Tak, A; Metgud, R; Astekar, M; Tak, M

2014-08-01

We evaluated micronuclei and other nuclear anomalies in exfoliated epithelial cells of the oral cavity on the side opposite the lesion targeted by radiotherapy and correlated them with radiation doses. Buccal smears were obtained from oral cancer patients undergoing radiotherapy with a cumulative dose of at least 1000 rad for 3 weeks and from controls matched for age, gender and habits. The exfoliated cells from the mucosa were collected using a cytobrush; smears were prepared, fixed in 80% methanol and stained using the Feulgen plus fast green method. The mean number of micronuclei and other nuclear anomalies/1000 cells was significantly greater in patients undergoing radiotherapy treatment, but the differences were not significant compared to radiation doses. It appears that radiotherapy has a potent clastogenic effect on buccal mucosal cells of oral cancer patients.

Correlative analysis of social support with anxiety and depression in men undergoing in vitro fertilization embryo transfer for the first time.

PubMed

Dong, Yue-Zhi; Yang, Xiao-Xia; Sun, Ying-Pu

2013-08-01

To explore the correlation between the level of social support and the extent of anxiety and depression in Chinese men undergoing in vitro fertilization embryo transfer (IVF-ET) for the first time, in order to provide a basis for male mental health counselling. Self-administered questionnaires covering general health status, anxiety (self-rating anxiety scale), depression (self-rating depression scale) and social support (social support rating scale) were completed by men undergoing their first round of IVF-ET. A total of 502 completed questionnaires were considered valid and were analysed. The anxiety, depression and social support scores for men undergoing their first round of IVF-ET were significantly higher than those for Chinese normative data. Social support was inversely correlated with anxiety and depression. These findings suggest that health care professionals should provide specific psychological counselling to Chinese men undergoing their first round of IVF-ET, in order to improve their psychological health and to facilitate increased levels of social support.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Efthimiopoulos, I.; Tsurkan, V.; Loidl, A.

We have conducted high-pressure measurements on the CuCr2O4 and CuCr2Se4 spinels to unravel the structural systematics of these materials under compression. Our studies have revealed diverse structural behavior in these two compounds. In particular, CuCr2O4 retains its ambient-pressure I41/amd structure up to 50 GPa. Close inspection of the lattice and interatomic parameters reveals a compressibility change near 23 GPa, which is accompanied by an expansion of the apical Cr–O bond distances. We speculate that an outer Cr3+ 3d orbital reorientation might be at play in this system, manifesting as the change in compressibility at that pressure point. On the othermore » hand, CuCr2Se4 undergoes a structural transformation from the starting Fd3¯m phase toward a monoclinic structure initiated at ~8 GPa and completed at ~20 GPa. This high-pressure behavior resembles that of ZnCr2Se4, and it appears that, unlike similar chalcogenide Cr spinels, steric effects take a leading role in this pressure-induced Fd3¯m → monoclinic transition. Close comparison of our results with the reported literature yields significant insights behind the pressure-induced structural systematics of this important family of materials, thus both allowing for the careful manipulation of the structural/physical properties of these systems by strain and promoting our understanding of similar pressure-induced effects in relevant systems.« less

What Predicts Patients’ Willingness to Undergo Online Treatment and Pay for Online Treatment? Results from a Web-Based Survey to Investigate the Changing Patient-Physician Relationship

PubMed Central

Bidmon, Sonja; Terlutter, Ralf

2016-01-01

Background Substantial research has focused on patients’ health information–seeking behavior on the Internet, but little is known about the variables that may predict patients’ willingness to undergo online treatment and willingness to pay additionally for online treatment. Objective This study analyzed sociodemographic variables, psychosocial variables, and variables of Internet usage to predict willingness to undergo online treatment and willingness to pay additionally for online treatment offered by the general practitioner (GP). Methods An online survey of 1006 randomly selected German patients was conducted. The sample was drawn from an e-panel maintained by GfK HealthCare. Missing values were imputed; 958 usable questionnaires were analyzed. Variables with multi-item measurement were factor analyzed. Willingness to undergo online treatment and willingness to pay additionally for online treatment offered by the GP were predicted using 2 multiple regression models. Results Exploratory factor analyses revealed that the disposition of patients’ personality to engage in information-searching behavior on the Internet was unidimensional. Exploratory factor analysis with the variables measuring the motives for Internet usage led to 2 separate factors: perceived usefulness (PU) of the Internet for health-related information searching and social motives for information searching on the Internet. Sociodemographic variables did not serve as significant predictors for willingness to undergo online treatment offered by the GP, whereas PU (B=.092, P=.08), willingness to communicate with the GP more often in the future (B=.495, P<.001), health-related information–seeking personality (B=.369, P<.001), actual use of online communication with the GP (B=.198, P<.001), and social motive (B=.178, P=.002) were significant predictors. Age, gender, satisfaction with the GP, social motive, and trust in the GP had no significant impact on the willingness to pay additionally for online treatment, but it was predicted by health-related information–seeking personality (B=.127, P=.07), PU (B=–.098, P=.09), willingness to undergo online treatment (B=.391, P<.001), actual use of online communication with the GP (B=.192, P=.001), highest education level (B=.178, P<.001), monthly household net income (B=.115, P=.01), and willingness to communicate with the GP online more often in the future (B=.076, P=.03). Conclusions Age, gender, and trust in the GP were not significant predictors for either willingness to undergo online treatment or to pay additionally for online treatment. Willingness to undergo online treatment was partly determined by the actual use of online communication with the GP, willingness to communicate online with the GP, health information–seeking personality, and social motivation for such behavior. Willingness to pay extra for online treatment was influenced by the monthly household net income category and education level. The results of this study are useful for online health care providers and physicians who are considering offering online treatments as a viable number of patients would appreciate the possibility of undergoing an online treatment offered by their GP. PMID:26846162

What Predicts Patients' Willingness to Undergo Online Treatment and Pay for Online Treatment? Results from a Web-Based Survey to Investigate the Changing Patient-Physician Relationship.

PubMed

Roettl, Johanna; Bidmon, Sonja; Terlutter, Ralf

2016-02-04

Substantial research has focused on patients' health information-seeking behavior on the Internet, but little is known about the variables that may predict patients' willingness to undergo online treatment and willingness to pay additionally for online treatment. This study analyzed sociodemographic variables, psychosocial variables, and variables of Internet usage to predict willingness to undergo online treatment and willingness to pay additionally for online treatment offered by the general practitioner (GP). An online survey of 1006 randomly selected German patients was conducted. The sample was drawn from an e-panel maintained by GfK HealthCare. Missing values were imputed; 958 usable questionnaires were analyzed. Variables with multi-item measurement were factor analyzed. Willingness to undergo online treatment and willingness to pay additionally for online treatment offered by the GP were predicted using 2 multiple regression models. Exploratory factor analyses revealed that the disposition of patients' personality to engage in information-searching behavior on the Internet was unidimensional. Exploratory factor analysis with the variables measuring the motives for Internet usage led to 2 separate factors: perceived usefulness (PU) of the Internet for health-related information searching and social motives for information searching on the Internet. Sociodemographic variables did not serve as significant predictors for willingness to undergo online treatment offered by the GP, whereas PU (B=.092, P=.08), willingness to communicate with the GP more often in the future (B=.495, P<.001), health-related information-seeking personality (B=.369, P<.001), actual use of online communication with the GP (B=.198, P<.001), and social motive (B=.178, P=.002) were significant predictors. Age, gender, satisfaction with the GP, social motive, and trust in the GP had no significant impact on the willingness to pay additionally for online treatment, but it was predicted by health-related information-seeking personality (B=.127, P=.07), PU (B=-.098, P=.09), willingness to undergo online treatment (B=.391, P<.001), actual use of online communication with the GP (B=.192, P=.001), highest education level (B=.178, P<.001), monthly household net income (B=.115, P=.01), and willingness to communicate with the GP online more often in the future (B=.076, P=.03). Age, gender, and trust in the GP were not significant predictors for either willingness to undergo online treatment or to pay additionally for online treatment. Willingness to undergo online treatment was partly determined by the actual use of online communication with the GP, willingness to communicate online with the GP, health information-seeking personality, and social motivation for such behavior. Willingness to pay extra for online treatment was influenced by the monthly household net income category and education level. The results of this study are useful for online health care providers and physicians who are considering offering online treatments as a viable number of patients would appreciate the possibility of undergoing an online treatment offered by their GP.

Trends in gestational age at time of surgical abortion for fetal aneuploidy and structural abnormalities.

PubMed

Davis, Anne R; Horvath, Sarah K; Castaño, Paula M

2017-03-01

Screening for fetal aneuploidy has evolved over the past 2 decades. Whether these advances impact gestational age at abortion has received little study. We sought to describe trends in the gestational age at the time of abortion by fetal diagnosis over an 11-year study period. We hypothesized that gestational age at time of abortion would decrease for fetal aneuploidy but remain unchanged for structural abnormalities. We conducted a retrospective case series of all women undergoing surgical abortion for fetal aneuploidy or structural abnormalities up to 24 weeks' gestation from 2004 through 2014 in a hospital operating room setting at a single, urban medical center. We excluded labor induction abortions (<1% of abortions at our medical center) and suction aspirations performed in the office practice. We performed suction aspiration up to 14 weeks and dilation and evacuation after that gestational age. We describe the median gestational age at abortion by fetal indication and year. For women undergoing abortion for fetal aneuploidy (n = 392), the median gestational age at time of abortion decreased from 19.0 weeks (interquartile range 18.0-21.0) in 2004 to 14.0 weeks (interquartile range 13.0-17.0) in 2014 (Kruskal-Wallis P < .0001). For women undergoing abortion for fetal structural abnormalities (n = 586), the median gestational age was ≥20 weeks for each year during the study interval (P = .1). As gestational age decreased in the fetal aneuploidy group, fewer women underwent dilation and evacuation and more became eligible for suction aspiration (<14 weeks). In 2004, >90% of women underwent dilation and evacuation for either indication. By 2014, 31% of women with fetal aneuploidy were eligible for suction aspiration compared to 11% of those with structural anomalies. Gestational age at the time of abortion for fetal aneuploidy decreased substantially from 2004 through 2014; earlier abortion is safer for women. In contrast, women seeking abortion for fetal structural abnormalities did not experience a change in timing. Legislation restricting gestational age at the time of abortion could disproportionately affect women with fetal structural abnormalities. Copyright © 2016 Elsevier Inc. All rights reserved.

Risk factors and outcomes of in-hospital cardiac arrest following pediatric heart operations of varying complexity.

PubMed

Gupta, Punkaj; Rettiganti, Mallikarjuna; Jeffries, Howard E; Scanlon, Matthew C; Ghanayem, Nancy S; Daufeldt, Jennifer; Rice, Tom B; Wetzel, Randall C

2016-08-01

Multi center data regarding cardiac arrest in children undergoing heart operations of varying complexity are limited. Children <18 years undergoing heart surgery (with or without cardiopulmonary bypass) in the Virtual Pediatric Systems (VPS, LLC) Database (2009-2014) were included. Multivariable mixed logistic regression models were adjusted for patient's characteristics, surgical risk category (STS-EACTS Categories 1, 2, and 3 classified as "low" complexity and Categories 4 and 5 classified as "high" complexity), and hospital characteristics. Overall, 26,909 patients (62 centers) were included. Of these, 2.7% had cardiac arrest after cardiac surgery with an associated mortality of 31%. The prevalence of cardiac arrest was lower among patients undergoing low complexity operations (low complexity vs. high complexity: 1.7% vs. 5.9%). Unadjusted outcomes after cardiac arrest were significantly better among patients undergoing low complexity operations (mortality: 21.6% vs. 39.1%, good neurological outcomes: 78.7% vs. 71.6%). In adjusted models, odds of cardiac arrest were significantly lower among patients undergoing low complexity operations (OR: 0.55, 95% CI: 0.46-0.66). Adjusted models, however, showed no difference in mortality or neurological outcomes after cardiac arrest regardless of surgical complexity. Further, our results suggest that incidence of cardiac arrest and mortality after cardiac arrest are a function of patient characteristics, surgical risk category, and hospital characteristics. Presence of around the clock in-house attending level pediatric intensivist coverage was associated with lower incidence of post-operative cardiac arrest, and presence of a dedicated cardiac ICU was associated with lower mortality after cardiac arrest. This study suggests that the patients undergoing high complexity operations are a higher risk group with increased prevalence of post-operative cardiac arrest. These data further suggest that patients undergoing high complexity operations can be rescued after cardiac arrest with a high survival rate. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Concurrent risk-reduction surgery in patients with increased lifetime risk for breast and ovarian cancer: an analysis of the National Surgical Quality Improvement Program (NSQIP) database.

PubMed

Elmi, Maryam; Azin, Arash; Elnahas, Ahmad; McCready, David R; Cil, Tulin D

2018-05-14

Patients with genetic susceptibility to breast and ovarian cancer are eligible for risk-reduction surgery. Surgical morbidity of risk-reduction mastectomy (RRM) with concurrent bilateral salpingo-oophorectomy (BSO) is unknown. Outcomes in these patients were compared to patients undergoing RRM without BSO using a large multi-institutional database. A retrospective cohort analysis was conducted using the American College of Surgeon's National Surgical Quality Improvement Program (NSQIP) 2007-2016 datasets, comparing postoperative morbidity between patients undergoing RRM with patients undergoing RRM with concurrent BSO. Patients with genetic susceptibility to breast/ovarian cancer undergoing risk-reduction surgery were identified. The primary outcome was 30-day postoperative major morbidity. Secondary outcomes included surgical site infections, reoperations, readmissions, length of stay, and venous thromboembolic events. A multivariate analysis was performed to determine predictors of postoperative morbidity and the adjusted effect of concurrent BSO on morbidity. Of the 5470 patients undergoing RRM, 149 (2.7%) underwent concurrent BSO. The overall rate of major morbidity and postoperative infections was 4.5% and 4.6%, respectively. There was no significant difference in the rate of postoperative major morbidity (4.5% vs 4.7%, p = 0.91) or any of the secondary outcomes between patients undergoing RRM without BSO vs. those undergoing RRM with concurrent BSO. Multivariable analysis showed Body Mass Index (OR 1.05; p < 0.001) and smoking (OR 1.78; p = 0.003) to be the only predictors associated with major morbidity. Neither immediate breast reconstruction (OR 1.02; p = 0.93) nor concurrent BSO (OR 0.94; p = 0.89) were associated with increased postoperative major morbidity. This study demonstrated that RRM with concurrent BSO was not associated with significant additional morbidity when compared to RRM without BSO. Therefore, this joint approach may be considered for select patients at risk for both breast and ovarian cancer.

Clinical and radiographic outcomes of bilateral decompression via a unilateral approach with transforaminal lumbar interbody fusion for degenerative lumbar spondylolisthesis with stenosis.

PubMed

Cheng, Xiaofei; Zhang, Kai; Sun, Xiaojiang; Zhao, Changqing; Li, Hua; Ni, Bin; Zhao, Jie

2017-08-01

Laminectomy with posterior lumbar interbody fusion (PLIF) has been shown to achieve satisfactory clinical outcomes, but it leads to potential adverse consequences associated with extensive disruption of posterior bony and soft tissue structures. This study aimed to compare the clinical and radiographic outcomes of bilateral decompression via a unilateral approach (BDUA) with transforaminal lumbar interbody fusion (TLIF) and laminectomy with PLIF in the treatment of degenerative lumbar spondylolisthesis (DLS) with stenosis. This is a prospective cohort study. This study compared 43 patients undergoing BDUA+TLIF and 40 patients undergoing laminectomy+PLIF. Visual analog scale (VAS) for low back pain and leg pain, Oswestry Disability Index (ODI), and Zurich Claudication Questionnaire (ZCQ) score. The clinical outcomes were assessed, and intraoperative data and complications were collected. Radiographic outcomes included slippage of the vertebra, disc space height, segmental lordosis, and final fusion rate. This study was supported by a grant from The National Natural Science Foundation of China (81572168). There were significant improvements in clinical and radiographic outcomes from before surgery to 3 months and 2 years after surgery within each group. Analysis of leg pain VAS and ZCQ scores showed no significant differences in improvement between groups at either follow-up. The mean improvements in low back pain VAS and ODI scores were significantly greater in the BDUA+TLIF group than in the laminectomy+PLIF group. No significant difference was found in the final fusion rate at 2-year follow-up. The BDUA+TLIF group had significantly less blood loss, shorter length of postoperative hospital stay, and lower complication rate compared with the laminectomy+PLIF group. When compared with the conventional laminectomy+PLIF procedure, the BDUA+TLIF procedure achieves similar and satisfactory effects of decompression and fusion for DLS with stenosis. The BDUA+TLIF procedure appears to be associated with less postoperative low back discomfort and quicker recovery. Copyright © 2017 Elsevier Inc. All rights reserved.

Experiences of the Breast Cancer Patients Undergoing Radiotherapy at a Public Hospital Peshawar Pakistan

PubMed Central

Habibullah, Gulzar; Gul, Raisa; Cassum, Shanaz; Elahi, Rehana

2018-01-01

Objective: This study aimed to explore the experiences of female breast cancer patients undergoing radiotherapy (RT) in a public hospital in Peshawar, Pakistan. Methods: This study employed a descriptive exploratory method. A purposive sample of 14 breast cancer women undergoing RT was selected for this study. Data were collected over the period of 5 months, using a semi-structured interview guide and conducting in-depth face-to-face interviews. These interviews were audio taped and transcribed by a bilingual transcriber. The translated version of the interview was coded, and the analysis was done manually. Results: Four main categories emerged from data analysis, which were: feelings and perceptions of the patients, their challenges, coping strategies, and teaching and informational needs. Conclusions: Women undergoing RT in this culture experience more intense psychological effects, as compared to the physical effects. Keeping in mind, the magnitude of the emotional stress experienced by the participants, recommendations for policy reforms, and training for female RT staff are suggested based on findings of this research. PMID:29607379

Evidence for ongoing extensional deformation in the western Swiss Alps and thrust-faulting in the southwestern Alpine foreland

NASA Astrophysics Data System (ADS)

Eva, Elena; Pastore, Stefania; Deichmann, Nicholas

1998-09-01

To verify the discordant orientations of P- and T-axes found by earlier studies in the Penninic domain of the southern Valais, Switzerland, and in the surrounding regions of France and Italy, we have evaluated the focal mechanisms of 11 of the best-recorded earthquakes that occurred in this area between 1985 and 1990. By employing two-dimensional ray-tracing techniques, we have made use of what is known about the lateral variations of the crustal structure to obtain constraints on the possible focal-depth range of the hypocenters and on the take-off angles at the source. In addition, we have been able to identify one of the two nodal planes as the actual fault plane of one of the events, based on high-resolution relative locations of its aftershocks. The resulting normal faulting and oblique-slip focal mechanisms show that, down to depths of about 10 km, the compressional structures of the Penninic nappes, which were formed during the Alpine orogeny, are presently undergoing extensional deformation and that a significant component of this extension is perpendicular to the Alpine arc. Thrust faulting focal mechanisms from events at the northwestern margin of the Po plain, however, indicate that the southern Alpine foreland is still subject to compressional deformation consistent with the large-scale stress field expected from the convergence of the African and European plates. Thus, our results lend support to geodynamic models that predict extensional deformation across the crest of a mountain range, while the flanks and lowlands continue to undergo crustal shortening.

Frequency of Dehiscence in Hand-Sutured and Stapled Intestinal Anastomoses in Dogs.

PubMed

Duell, Jason R; Thieman Mankin, Kelley M; Rochat, Mark C; Regier, Penny J; Singh, Ameet; Luther, Jill K; Mison, Michael B; Leeman, Jessica J; Budke, Christine M

2016-01-01

To determine the frequency of dehiscence of hand-sutured and stapled intestinal anastomoses in the dog and compare the surgery duration for the methods of anastomosis. Historical cohort study. Two hundred fourteen client-owned dogs undergoing hand-sutured (n = 142) or stapled (n = 72) intestinal anastomoses. Medical records from 5 referral institutions were searched for dogs undergoing intestinal resection and anastomosis between March 2006 and February 2014. Demographic data, presence of septic peritonitis before surgery, surgical technique (hand-sutured or stapled), surgery duration, surgeon (resident versus faculty member), indication for surgical intervention, anatomic location of resection and anastomosis, and if dehiscence was noted postoperatively were retrieved. Estimated frequencies were summarized and presented as proportions and 95% confidence intervals (CI) and continuous outcomes as mean (95% CI). Comparisons were made across methods of anastomosis. Overall, 29/205 dogs (0.14, 95% CI 0.10-00.19) had dehiscence, including 21/134 dogs (0.16, 0.11-0.23) undergoing hand-sutured anastomosis and 8/71 dogs (0.11, 0.06-0.21) undergoing stapled anastomosis. There was no significant difference in the frequency of dehiscence across anastomosis methods (χ(2), P = .389). The mean (95% CI) surgery duration of 140 minutes (132-147) for hand- sutured anastomoses and 108 minutes (99-119) for stapled anastomoses was significantly different (t-test, P < .001). No significant difference in frequency of dehiscence was noted between hand- sutured and stapled anastomoses in dogs but surgery duration is significantly reduced by the use of staples for intestinal closure. © Copyright 2015 by The American College of Veterinary Surgeons.

Cellular Profile and Expression of Immunologic Markers in Chronic Apical Periodontitis from HIV-infected Patients Undergoing Highly Active Antiretroviral Therapy.

PubMed

Gama, Túlio Gustavo Veiga; Pires, Fabio Ramoa; Armada, Luciana; Gonçalves, Lucio Souza

2016-06-01

This study tested the hypothesis that the inflammatory cell profile (CD3-, CD4-, CD8-, CD20-, and CD68-positive cells) and the expression of immunologic markers (tumor necrosis factor α, interferon-γ, interleukin-6, and interleukin-18) in chronic apical periodontitis are the same between non-HIV-infected patients and HIV-infected patients undergoing highly active antiretroviral therapy (HAART). Thirty-four surgically excised chronic apical periodontitis lesions were sampled from 34 patients (17 HIV-infected and 17 non-HIV-infected). The lesions were extracted from teeth with no previous endodontic treatment. All HIV-infected patients were undergoing HAART. The specimens were submitted to histopathologic and immunohistochemical analyses by using an optical microscope. Immunoexpression was graded into 2 levels, focal to weak and moderate to strong. The χ(2), Fisher exact, and Mann-Whitney tests were used to analyze all significant differences between groups. Periapical cysts represented 70.6% and 52.9% of the lesions in the HIV-infected and non-HIV-infected groups, respectively; however, no statistically significant difference was observed (P = .481). There were no statistically significant differences between groups for the inflammatory cell profile and for any of the immunologic markers (P > .05). There are no statistically significant differences of the cellular profile and expression of immunologic markers in chronic apical periodontitis between non-HIV-infected patients and HIV-infected patients undergoing HAART. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Perioperative depression or anxiety and postoperative mortality in cardiac surgery: a systematic review and meta-analysis.

PubMed

Takagi, Hisato; Ando, Tomo; Umemoto, Takuya

2017-12-01

We performed a systematic review and meta-analysis to determine whether perioperative depression and anxiety are associated with increased postoperative mortality in patients undergoing cardiac surgery. MEDLINE and EMBASE were searched through January 2017 using PubMed and OVID, to identify observational studies enrolling patients undergoing cardiac surgery and reporting relative risk estimates (RREs) (including odds, hazard, or mortality ratios) of short term (30 days or in-hospital) and/or late all-cause mortality for patients with versus without perioperative depression or anxiety. Study-specific estimates were combined using inverse variance-weighted averages of logarithmic RREs in the random-effects models. Our search identified 16 eligible studies. In total, the present meta-analysis included data on 236,595 patients undergoing cardiac surgery. Pooled analysis demonstrated that perioperative depression was significantly associated with increased both postoperative early (RRE, 1.44; 95% confidence interval [CI] 1.01-2.05; p = 0.05) and late mortality (RRE, 1.44; 95% CI 1.24-1.67; p < 0.0001), and that perioperative anxiety significantly correlated with increased postoperative late mortality (RRE, 1.81; 95% CI 1.20-2.72; p = 0.004). The relation between anxiety and early mortality was reported in only one study and not statistically significant. In the association of depression with late mortality, there was no evidence of significant publication bias and meta-regression indicated that the effects of depression are not modulated by the duration of follow-up. In conclusion, perioperative depression and anxiety may be associated with increased postoperative mortality in patients undergoing cardiac surgery.

Effects of Reiki on Pain, Anxiety, and Blood Pressure in Patients Undergoing Knee Replacement: A Pilot Study.

PubMed

Baldwin, Ann Linda; Vitale, Anne; Brownell, Elise; Kryak, Elizabeth; Rand, William

This blinded, controlled pilot study investigated the effects of Reiki on 46 patients undergoing knee replacement surgery. Of the 3 groups, Reiki, Sham Reiki, and Standard of Care, only the Reiki group showed significant reductions in pain, blood pressure, respiration rate, and state anxiety, which provides evidence for a full-scale clinical study.

Risk of iron overload is decreased in beating heart coronary artery surgery compared to conventional bypass.

PubMed

Mumby, S; Koh, T W; Pepper, J R; Gutteridge, J M

2001-11-29

Conventional cardiopulmonary bypass surgery (CCPB) increases the iron loading of plasma transferrin often to a state of plasma iron overload, with the presence of low molecular mass iron. Such iron is a potential risk factor for oxidative stress and microbial virulence. Here we assess 'off-pump' coronary artery surgery on the beating heart for changes in plasma iron chemistry. Seventeen patients undergoing cardiac surgery using the 'Octopus' myocardial wall stabilisation device were monitored at five time points for changes in plasma iron chemistry. This group was further divided into those (n=9) who had one- or two- (n=8) vessel grafts, and compared with eight patients undergoing conventional coronary artery surgery. Patients undergoing beating heart surgery had significantly lower levels of total plasma non-haem iron, and a decreased percentage saturation of their transferrin at all time points compared to conventional bypass patients. Plasma iron overload occurred in only one patient undergoing CCPB. Beating heart surgery appears to decrease red blood cell haemolysis, and tissue damage during the operative procedures and thereby significantly decreases the risk of plasma iron overload associated with conventional bypass.

The Regulatory Subunit of PKA-I Remains Partially Structured and Undergoes β-Aggregation upon Thermal Denaturation

PubMed Central

Dao, Khanh K.; Pey, Angel L.; Gjerde, Anja Underhaug; Teigen, Knut; Byeon, In-Ja L.; Døskeland, Stein O.; Gronenborn, Angela M.; Martinez, Aurora

2011-01-01

Background The regulatory subunit (R) of cAMP-dependent protein kinase (PKA) is a modular flexible protein that responds with large conformational changes to the binding of the effector cAMP. Considering its highly dynamic nature, the protein is rather stable. We studied the thermal denaturation of full-length RIα and a truncated RIα(92-381) that contains the tandem cyclic nucleotide binding (CNB) domains A and B. Methodology/Principal Findings As revealed by circular dichroism (CD) and differential scanning calorimetry, both RIα proteins contain significant residual structure in the heat-denatured state. As evidenced by CD, the predominantly α-helical spectrum at 25°C with double negative peaks at 209 and 222 nm changes to a spectrum with a single negative peak at 212–216 nm, characteristic of β-structure. A similar α→β transition occurs at higher temperature in the presence of cAMP. Thioflavin T fluorescence and atomic force microscopy studies support the notion that the structural transition is associated with cross-β-intermolecular aggregation and formation of non-fibrillar oligomers. Conclusions/Significance Thermal denaturation of RIα leads to partial loss of native packing with exposure of aggregation-prone motifs, such as the B' helices in the phosphate-binding cassettes of both CNB domains. The topology of the β-sandwiches in these domains favors inter-molecular β-aggregation, which is suppressed in the ligand-bound states of RIα under physiological conditions. Moreover, our results reveal that the CNB domains persist as structural cores through heat-denaturation. PMID:21394209

Basal ganglia, thalamus and neocortical atrophy predicting slowed cognitive processing in multiple sclerosis.

PubMed

Batista, Sonia; Zivadinov, Robert; Hoogs, Marietta; Bergsland, Niels; Heininen-Brown, Mari; Dwyer, Michael G; Weinstock-Guttman, Bianca; Benedict, Ralph H B

2012-01-01

Information-processing speed (IPS) slowing is a primary cognitive deficit in multiple sclerosis (MS). Basal ganglia, thalamus and neocortex are thought to have a key role for efficient information-processing, yet the specific relative contribution of these structures for MS-related IPS impairment is poorly understood. To determine if basal ganglia and thalamus atrophy independently contribute to visual and auditory IPS impairment in MS, after controlling for the influence of neocortical volume, we enrolled 86 consecutive MS patients and 25 normal controls undergoing 3T brain MRI and neuropsychological testing. Using Sienax and FIRST software, neocortical and deep gray matter (DGM) volumes were calculated. Neuropsychological testing contributed measures of auditory and visual IPS using the Paced Auditory Serial Addition Test (PASAT) and the Symbol Digit Modalities Test (SDMT), respectively. MS patients exhibited significantly slower IPS relative to controls and showed reduction in neocortex, caudate, putamen, globus pallidus, thalamus and nucleus accumbens volume. SDMT and PASAT were significantly correlated with all DGM regions. These effects were mitigated by controlling for the effects of neocortical volume, but all DGM volumes remained significantly correlated with SDMT, putamen (r = 0.409, p < 0.001) and thalamus (r = 0.362, p < 0.001) having the strongest effects, whereas for PASAT, the correlation was significant for putamen (r = 0.313, p < 0.01) but not for thalamus. We confirm the significant role of thalamus atrophy in MS-related IPS slowing and find that putamen atrophy is also a significant contributor to this disorder. These DGM structures have independent, significant roles, after controlling for the influence of neocortex atrophy.

Anesthetic complications in dogs undergoing hepatic surgery: cholecystectomy versus non-cholecystectomy.

PubMed

Burns, Brigid R; Hofmeister, Erik H; Brainard, Benjamin M

2014-03-01

To determine if dogs that undergo laparotomy for cholecystectomy suffer from a greater number or magnitude of perianesthetic complications, including hypotension, hypothermia, longer recovery time, and lower survival rate, than dogs that undergo laparotomy for hepatic surgery without cholecystectomy. Retrospective cohort study. One hundred and three dogs, anesthetised between January 2007 and October 2011. The variables collected from the medical record included age, weight, gender, surgical procedure, pre-operative bloodwork, American Society of Anesthesiologists (ASA) status, emergency status, total bilirubin concentration, anesthetic agents administered, body temperature nadir, final body temperature, hypotension, duration of hypotension, blood pressure nadir, intraoperative drugs, anesthesia duration, surgery duration, time to extubation, final diagnosis, days spent in the intensive care unit (ICU), total bill, survival to discharge, and survival to follow-up. No significant difference in body temperature nadir, final temperature, presence of hypotension, duration of hypotension, blood pressure nadir, the use of inotropes, or final outcome was found between dogs undergoing cholecystectomy and dogs undergoing exploratory laparotomy for other hepatic disease. Dogs that had cholecystectomy had longer anesthesia durations and longer surgery durations than dogs that did not have cholecystectomy. No significant differences existed for temperature nadir (34.8 versus 35.3°C; non-cholecystectomy versus cholecystectomy), final temperature (35.6 versus 35.9°C), time to extubation (30 versus 49 minutes), duration of hypotension (27 versus 21 minutes), or MAP nadir (56 versus 55 mmHg). Hypotension occurred in 66% and 74% and inotropes were used in 64% and 53%, for non-cholecystectomy and cholecystectomy patients, respectively. Dogs that underwent cholecystectomies did not suffer a greater number of anesthesia complications than did dogs undergoing hepatic surgery without cholecystectomies. © 2013 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesia and Analgesia.

Effect of Single vs Bilateral Lung Transplantation on Plasma Surfactant Protein D Levels in Idiopathic Pulmonary Fibrosis

PubMed Central

Beers, Michael F.; Ahya, Vivek N.; Kawut, Steven M.; Sims, Karen D.; Lederer, David J.; Palmer, Scott M.; Wille, Keith; Lama, Vibha N.; Shah, Pali D.; Orens, Jonathan B.; Bhorade, Sangeeta; Crespo, Maria; Weinacker, Ann; Demissie, Ejigayehu; Bellamy, Scarlett; Christie, Jason D.; Ware, Lorraine B.

2011-01-01

Background: Serum levels of surfactant protein D (SP-D) have been suggested as reflecting epithelial damage in acute lung injury, COPD, and idiopathic pulmonary fibrosis (IPF). However, little is known about SP-D levels in the setting of lung transplantation. Methods: We examined plasma SP-D levels in 104 subjects from a prospective, multicenter cohort study of lung allograft recipients. Plasma SP-D was measured by enzyme-linked immunosorbent assay prior to transplant and daily for 3 days after transplant. Results: Subjects undergoing transplant for IPF had higher baseline SP-D levels (median, 325 ng/mL) compared with subjects with cystic fibrosis, COPD, and pulmonary hypertension (median, 100, 80, and 82 ng/mL, respectively; P = .0001). Among subjects with IPF undergoing bilateral transplant, SP-D levels declined rapidly postoperatively. In contrast, SP-D levels in subjects undergoing single lung transplant for IPF remained significantly higher than those of bilateral allograft recipients. Among subjects undergoing single lung transplant for IPF, the development of primary graft dysfunction (PGD) was associated with a subsequent rise in SP-D levels, whereas SP-D levels in IPF subjects undergoing bilateral transplant declined, even in the presence of grade 3 PGD. Importantly, single lung allograft recipients without PGD had higher postoperative SP-D levels than bilateral allograft recipients with PGD. Conclusions: Subjects undergoing lung transplant for IPF have significantly higher baseline plasma SP-D levels compared with those with other diagnoses. Plasma SP-D is likely a biomarker of the air-blood barrier integrity in the native IPF lung, but may be less useful as a biomarker of PGD after transplant. PMID:21349925

A Critical Analysis of the Utility of Intraoperative Angiography.

PubMed

Ares, William J; Kenmuir, Cynthia L; Panczykowski, David M; Weiner, Gregory M; Jadhav, Ashu P; Jovin, Tudor G; Gross, Bradley A; Jankowitz, Brian T

2018-02-01

Intraoperative digital subtraction angiography (ioDSA) is touted as the gold standard imaging evaluation for aneurysm clip constructs. Candid evaluations of its limitations are sparse. A prospectively collected hospital billing database was queried to identify craniotomies for aneurysm clipping from January 2010 to December 2013. We evaluated the rate of occult residual and parent vessel stenosis determined on follow-up angiography for patients undergoing ioDSA and those not undergoing ioDSA. Comparisons were performed via Fisher exact test, with P < 0.05 considered statistically significant. From our database search, we found 187 patients who underwent ioDSA after aneurysm clipping and an additional 91 patients who did not. Results from ioDSA influenced operative management in 17% of cases. Sixty-four patients with 70 treated aneurysms undergoing ioDSA had postoperative angiography; 7 occult residuals were discovered, yielding a 10% false-negative rate, with 10% of aneurysms showing residual. Occult residuals at the middle cerebral artery bifurcation represented most discovered residuals (6/7). Thirty-two patients with 37 treated aneurysms did not undergo ioDSA and had angiographic follow-up; 24% of patients were found to have residual aneurysms (P = 0.08 compared with patients undergoing ioDSA). Residuals at the anterior communicating artery (ACoA) represented 56% of all residuals, whereas the ACoA represented only 18% of aneurysms clipped. The rate of residuals was significantly higher than that for patients with clipped ACoA aneurysms undergoing ioDSA (P = 0.008). ioDSA influenced management in nearly one fifth of cases. It can be particularly beneficial in detecting residuals for ACoA aneurysms; its benefit was less apparent for middle cerebral artery aneurysms. Copyright © 2017 Elsevier Inc. All rights reserved.

NASA WISE Cryostat

NASA Image and Video Library

2009-10-13

Initial assembly of NASA Wide-field Infrared Survey Explorer cryostat. The cryostat is a 2-stage solid hydrogen dewar that is used to cool the WISE optics and detectors. Here the cryostat internal structures are undergoing their initial vacuum pumpdown.

Crystal structure transformation in potassium acrylate

NASA Astrophysics Data System (ADS)

Pai Verneker, V. R.; Vasanthakumari, R.

1983-10-01

Potassium acrylate undergoes a reversible phase transformation around 335°K with an activation energy of 133 kcal/mole. Differential scanning calorimetry and high temperature X-ray powder diffraction techniques have been used to probe this phenomenon.

KSC-03pd0262

NASA Image and Video Library

2003-02-04

KENNEDY SPACE CENTER, FLA. -- United Space Alliance (USA) technicians install thermal protection system tiles on Space Shuttle Discovery. Discovery is undergoing its Orbiter Major Modification Period, a regularly scheduled structural inspection and modification downtime, which began in September 2002. .

Structural transitions in Cowpea chlorotic mottle virus (CCMV)

NASA Astrophysics Data System (ADS)

Liepold, Lars O.; Revis, Jennifer; Allen, Mark; Oltrogge, Luke; Young, Mark; Douglas, Trevor

2005-12-01

Viral capsids act as molecular containers for the encapsulation of genomic nucleic acid. These protein cages can also be used as constrained reaction vessels for packaging and entrapment of synthetic cargos. The icosahedral Cowpea chlorotic mottle virus (CCMV) is an excellent model for understanding the encapsulation and packaging of both genomic and synthetic materials. High-resolution structural information of the CCMV capsid has been invaluable for evaluating structure-function relationships in the assembled capsid but does not allow insight into the capsid dynamics. The dynamic nature of the CCMV capsid might play an important role in the biological function of the virus. The CCMV capsid undergoes a pH and metal ion dependent reversible structural transition where 60 separate pores in the capsid open or close, exposing the interior of the protein cage to the bulk medium. In addition, the highly basic N-terminal domain of the capsid, which is disordered in the crystal structure, plays a significant role in packaging the viral cargo. Interestingly, in limited proteolysis and mass spectrometry experiments the N-terminal domain is the first part of the subunit to be cleaved, confirming its dynamic nature. Based on our fundamental understanding of the capsid dynamics in CCMV, we have utilized these aspects to direct packaging of a range of synthetic materials including drugs and inorganic nanoparticles.

Atomic resolution structure of the cytoplasmic domain of Yersinia pestis YscU, a regulatory switch involved in type III secretion

PubMed Central

Lountos, George T; Austin, Brian P; Nallamsetty, Sreedevi; Waugh, David S

2009-01-01

Crystal structures of cleaved and uncleaved forms of the YscU cytoplasmic domain, an essential component of the type III secretion system (T3SS) in Yersinia pestis, have been solved by single-wavelength anomolous dispersion and refined with X-ray diffraction data extending up to atomic resolution (1.13 Å). These crystallographic studies provide structural insights into the conformational changes induced upon auto-cleavage of the cytoplasmic domain of YscU. The structures indicate that the cleaved fragments remain bound to each other. The conserved NPTH sequence that contains the site of the N263-P264 peptide bond cleavage is found on a β-turn which, upon cleavage, undergoes a major reorientation of the loop away from the catalytic N263, resulting in altered electrostatic surface features at the site of cleavage. Additionally, a significant conformational change was observed in the N-terminal linker regions of the cleaved and noncleaved forms of YscU which may correspond to the molecular switch that influences substrate specificity. The YscU structures determined here also are in good agreement with the auto-cleavage mechanism described for the flagellar homolog FlhB and E. coli EscU. PMID:19165725

Phase-space perspective on the wavelength-dependent electron correlation of strong-field double ionization of Xe

NASA Astrophysics Data System (ADS)

Shao, Yun; Yuan, Zongqiang; Ye, Difa; Fu, Libin; Liu, Ming-Ming; Sun, Xufei; Wu, Chengyin; Liu, Jie; Gong, Qihuang; Liu, Yunquan

2017-12-01

We measure the wavelength-dependent correlated-electron momentum (CEM) spectra of strong-field double ionization of Xe atoms, and observe a significant change from a roughly nonstructured (uncorrelated) pattern at 795 nm to an elongated distribution with V-shaped structure (correlated) at higher wavelengths of 1320 and 1810 nm, pointing to the transition of the ionization dynamics imprinted in the momentum distributions. These observations are well reproduced by a semiclassical model using Green-Sellin-Zachor potential to take into account the screening effect. We show that the momentum distribution of Xe2+ undergoes a bifurcation structure emerging from single-hump to double-hump structure as the laser wavelength increases, which is dramatically different from that of He2+, indicating the complex multi-electron effect. By back analyzing the double ionization trajectories in the phase space (the initial transverse momentum and the laser phase at the tunneling exit) of the first tunneled electrons, we provide deep insight into the physical origin for electron correlation dynamics. We find that a random distribution in phase-space is responsible for a less distinct structured CEM spectrum at shorter wavelength. While increasing the laser wavelength, a topology-invariant pattern in phase-space appears, leading to the clearly visible V-shaped structures.

Polyimine and its potential significance for prebiotic chemistry on Titan

NASA Astrophysics Data System (ADS)

Rahm, Martin; Lunine, Jonathan I.; Usher, David; Shalloway, David

2016-10-01

Hydrogen cyanide (HCN), a key reagent in prebiotic chemistry, is being generated in large amounts in the atmosphere of Titan. Contradictions between Cassini-Huygens measurements of the atmosphere and the surface of Titan, suggest that HCN is undergoing reaction chemistry, despite the frigid temperatures of 90-94 K. We will discuss computational results [1] investigating polyimine as one potential explanation for this observation. Polyimine is a polymer identified as the major component of polymerized HCN in laboratory experiments. It is flexible, which aids low temperature mobility, and it is able to form intermolecular and intramolecular =N-H...N hydrogen bonds, allowing for different polymorphs. Polymorphs have been predicted and explored by density functional theory coupled with a structure-searching algorithm. We have calculated the thermodynamics of polymerization, and show that polyimine is capable of absorbing light in a window of relative transparency in Titan's atmosphere. Light absorption and the possible catalytic functions of polyimine are suggestive of it driving photochemistry on the surface, with potential prebiotic implications.References:[1] M. Rahm, J. I. Lunine, D. Usher, D. Shalloway, "Polymorphism and electronic structure of polyimine and its potential significance for prebiotic chemistry on Titan", PNAS, early view. doi: 10.1073/pnas.1606634113

Refinement of the crystal structure of the high-temperature phase G0 in (NH4)2WO2F4 (powder, x-ray, and neutron scattering)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Novak, D. M.; Smirnov, Lev S; Kolesnikov, Alexander I

2013-01-01

The (NH4)2WO2F4 compound undergoes a series of phase transitions: G0 -> 201 K -> G1 -> 160 K -> G2, with a significant change in entropy ( S1 ~ Rln10 at the G0 -> G1 transition), which indicates significant orientational disordering in the G0 phase and the order disorder type of the phase transition. X-ray diffraction is used to identify the crystal structure of the G0 phase as rhombohedral (sp. gr. Cmcm, Z = 4), determine the lattice parameters and the positions of all atoms (except hydrogen), and show that [WO2F4]2 ions can form a superposition of dynamic and staticmore » orientational disorders in the anionic sublattice. A determination of the orientational position of [NH4]+ ions calls for the combined method of elastic and inelastic neutron scattering. Inelastic neutron scattering is used to determine the state of hindered rotation for ammonium ions in the G0 phase. Powder neutron diffraction shows that the orientational disorder of NH4 ions can adequately be described within the free rotation approximation.« less

Impact of the severity of end-stage liver disease in cardiac structure and function.

PubMed

Silvestre, Odilson Marcos; Bacal, Fernando; de Souza Ramos, Danusa; Andrade, Jose L; Furtado, Meive; Pugliese, Vincenzo; Belleti, Elisangela; Andraus, Wellington; Carrilho, Flair José; Carneiro D'Albuquerque, Luiz Augusto; Queiroz Farias, Alberto

2013-01-01

The impact of end-stage liver disease (ESLD) in cardiac remodeling of patients with cirrhosis is unknown. Our aim was to correlate the severity of ESLD with morphologic and functional heart changes. 184 patients underwent a protocol providing data on the severity of ESLD and undergoing echocardiography to assess the diameters of the left atrium and right ventricle; the systolic and diastolic diameters of the left ventricle, interventricular septum, and posterior wall of the left ventricle; systolic pulmonary artery pressure; ejection fraction; and diastolic function. Severity of ESLD was assessed by the Model for End-Stage Liver Disease (MELD) score. Left-atrial diameter (r = 0.323; IC 95% 0.190-0.455; p < 0.001), left-ventricular diastolic diameter (r = 0.177; IC 95% 0.033-0.320; p = 0.01) and systolic pulmonary artery pressure (r = 0.185; IC 95% 0.036-0.335; p = 0.02) significantly correlated with MELD score. Patients with MELD ≥ 16 had significantly higher left-atrial diameter and systolic pulmonary artery pressure, compared with patients with MELD scores < 16 points. Changes in cardiac structure and function correlate with the severity of ESLD.

A finite element model of a MEMS-based surface acoustic wave hydrogen sensor.

PubMed

El Gowini, Mohamed M; Moussa, Walied A

2010-01-01

Hydrogen plays a significant role in various industrial applications, but careful handling and continuous monitoring are crucial since it is explosive when mixed with air. Surface Acoustic Wave (SAW) sensors provide desirable characteristics for hydrogen detection due to their small size, low fabrication cost, ease of integration and high sensitivity. In this paper a finite element model of a Surface Acoustic Wave sensor is developed using ANSYS12© and tested for hydrogen detection. The sensor consists of a YZ-lithium niobate substrate with interdigital electrodes (IDT) patterned on the surface. A thin palladium (Pd) film is added on the surface of the sensor due to its high affinity for hydrogen. With increased hydrogen absorption the palladium hydride structure undergoes a phase change due to the formation of the β-phase, which deteriorates the crystal structure. Therefore with increasing hydrogen concentration the stiffness and the density are significantly reduced. The values of the modulus of elasticity and the density at different hydrogen concentrations in palladium are utilized in the finite element model to determine the corresponding SAW sensor response. Results indicate that with increasing the hydrogen concentration the wave velocity decreases and the attenuation of the wave is reduced.

Awareness and Attitude of the General Public Toward HIV/AIDS in Coastal Karnataka

PubMed Central

Unnikrishnan, B; Mithra, Prasanna P; T, Rekha; B, Reshmi

2010-01-01

Objective: To assess the awareness and attitude of the general public toward people living with HIV/AIDS (PLWHA) in Mangalore, a city in Coastal Karnataka. Design: Community-based cross-sectional study. Materials and Methods: The study population included 630 individuals aged 18 years and above. The information was collected using a semi structured pre-tested questionnaire. The questionnaire consisted of 24 questions regarding awareness of the modes of transmission of HIV/AIDS (nine questions) and questions to assess the attitude toward People Living With HIV/AIDS (PLWHA) (15 questions). Statistical package SPSS version 11.5 was used, Chi-square test was conducted and P < 0.05 was considered as statistically significant. Results: About one-third of the study population thought that one could get infected by merely touching an HIV positive individual. Approximately 45% stated that they would dismiss their maid on finding out her HIV positive status. About 54% were willing to undergo the HIV test. The respondents with less than secondary school education had a discriminatory attitude toward HIV positive people, with regard to them deserving to suffer, dismissing a HIV positive maid, hesitating to sit next to a HIV positive person in the bus, divorcing the infected spouse, and willingness to get tested for HIV, which was found to be statistically significant. Conclusion: Stigma among the general public was mostly due to fear of contracting the illness. Stigma does exist to significant degrees among the educated people, which was suggested by about 45% of the participants being willing to undergo the HIV test. There is a need for greater attempts toward making information regarding HIV/AIDS available to every individual of the society. PMID:20606940

Compensatory Renal Hypertrophy and the Uptake of Cysteine S-Conjugates of Hg2+ in Isolated S2 Proximal Tubular Segments.

PubMed

Bridges, Christy C; Barfuss, Delon W; Joshee, Lucy; Zalups, Rudolfs K

2016-12-01

Chronic kidney disease is characterized by a progressive and permanent loss of functioning nephrons. In order to compensate for this loss, the remaining functional nephrons undergo significant structural and functional changes. We hypothesize that luminal uptake of inorganic mercury (Hg 2+ ), as a conjugate of cysteine (Cys; Cys-S-Hg-S-Cys), is enhanced in S2 segments of proximal tubules from the remnant kidney of uninephrectomized (NPX) rabbits. To test this hypothesis, we measured uptake and accumulation of Cys-S-Hg-S-Cys in isolated perfused S2 segments of proximal tubules from normal (control) and NPX rabbits. The remnant kidney in NPX rabbits undergoes significant hypertrophy during the initial 3 weeks following surgery. Tubules isolated from NPX rabbits were significantly larger in diameter and volume than those from control rabbits. Moreover, real-time PCR analyses of proximal tubules indicated that the expression of selected membrane transporters was greater in kidneys of NPX animals than in kidneys of control animals. When S2 segments from control and NPX rabbits were perfused with cystine or Cys-S-Hg-S-Cys, we found that the rates of luminal disappearance and tubular accumulation of Hg 2+  were greater in tubules from NPX animals. These increases were inhibited by the addition of various amino acids to the perfusate. Taken together, our data suggest that hypertrophic changes in proximal tubules lead to an enhanced ability of these tubules to take up and accumulate Hg 2 . © The Author 2016. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Driving performance of stable outpatients with depression undergoing real-world treatment.

PubMed

Miyata, Akemi; Iwamoto, Kunihiro; Kawano, Naoko; Aleksic, Branko; Ando, Masahiko; Ebe, Kazutoshi; Fujita, Kiyoshi; Yokoyama, Motonori; Akiyama, Tsuyoshi; Igarashi, Yoshio; Ozaki, Norio

2018-06-01

Although the effects of psychotropics on driving ability have received much attention, little research is available on driving performance of stable outpatients with depression undergoing real-world treatment. This observational study investigated driving performance, cognitive functions, and depressive symptomatology of partly remitted outpatients with depression under daily-practice psychopharmacologic treatment. Seventy stable outpatients with depression and 67 healthy volunteers were enrolled. Patients' prescriptions were not controlled in order to capture the real-world treatment environment. Participants underwent three driving tasks - road-tracking, car-following, and harsh-braking - using a driving simulator, and three cognitive tasks - Continuous Performance Test, Wisconsin Card Sorting Test, and Trail-Making Test. The Symptom Assessment Scale - Structured Interview Guide for the Hamilton Depression Rating Scale, Beck Depression Inventory-II, Social Adaptation Self-Evaluation Scale, and Stanford Sleepiness Scale were also completed. Although many patients received various pharmacologic treatments, there were no significant differences in the three driving tasks between outpatients with depression and healthy controls. Difficulty of maintaining set in the Wisconsin Card Sorting Test was significantly increased in patients with depression. Results on the Social Adaptation Self-Evaluation Scale were significantly associated with road-tracking and car-following performance, in contrast to results on the Hamilton Depression Rating Scale and the Beck Depression Inventory-II. We conclude that partly remitted depressive patients under steady-state pharmacologic treatment do not differ from healthy controls with respect to driving performance, which seems to be more affected by psychosocial functioning than by pharmacologic agents. This, however, should be investigated systematically in an off/on study. © 2018 The Authors. Psychiatry and Clinical Neurosciences © 2018 Japanese Society of Psychiatry and Neurology.

Clinical predictors of elective total joint replacement in persons with end-stage knee osteoarthritis.

PubMed

Zeni, Joseph A; Axe, Michael J; Snyder-Mackler, Lynn

2010-05-06

Arthritis is a leading cause of disability in the United States. Total knee arthroplasty (TKA) has become the gold standard to manage the pain and disability associated with knee osteoarthritis (OA). Although more than 400,000 primary TKA surgeries are performed each year in the United States, not all individuals with knee OA elect to undergo the procedure. No clear consensus exists on criteria to determine who should undergo TKA. The purpose of this study was to determine which clinical factors will predict the decision to undergo TKA in individuals with end-stage knee OA. Knowledge of these factors will aid in clinical decision making for the timing of TKA. Functional data from one hundred twenty persons with end-stage knee OA were obtained through a database. All of the individuals complained of knee pain during daily activities and had radiographic evidence of OA. Functional and clinical tests, collectively referred to as the Delaware Osteoarthritis Profile, were completed by a physical therapist. This profile consisted of measuring height, weight, quadriceps strength and active knee range of motion, while functional mobility was assessed using the Timed Up and Go (TUG) test and the Stair Climbing Task (SCT). Self-perceived functional ability was measured using the activities of daily living subscale of the Knee Outcome Survey (KOS-ADLS). A logistic regression model was used to identify variables predictive of TKA use. Forty subjects (33%) underwent TKA within two years of evaluation. These subjects were significantly older and had significantly slower TUG and SCT times (p < 0.05). Persons that underwent TKA were also significantly weaker, had lower self-reported function and had less knee extension than persons who did not undergo TKA. No differences between groups were seen for BMI, gender, knee flexion ROM and unilateral versus bilateral joint disease. Using backward regression, age, knee extension ROM and KOS-ADLS together significantly predicted whether or not a person would undergo TKA (p

Hepatocellular integrity in patients requiring parenteral nutrition: comparison of structured MCT/LCT vs. a standard MCT/LCT emulsion and a LCT emulsion.

PubMed

Piper, S N; Röhm, K D; Boldt, J; Odermatt, B; Maleck, W H; Suttner, S W

2008-07-01

The aetiology of parenteral nutrition-associated hepatic injury remains unresolved. The aim of the study was to evaluate the effects of structured triglycerides in parenteral nutrition compared either to a physical medium-chain triglycerides (MCT)/long-chain triglcerides (LCT) mixture or to a LCT emulsion on hepatic integrity. In a randomized, double-blinded trial, we studied 45 patients undergoing abdominal surgery, who were expected to receive parenteral nutrition for 5 days. Patients were allocated to one of three nutrition regimens: Group A (n = 15) received structured triglycerides, Group B (n = 15) a MCT/LCT and Group C (n = 15) a LCT lipid emulsion. Before the start of parenteral nutrition (T0), 24 h (T1), 48 h (T2), 72 h (T3) and 120 h (T4) after start of infusion the following parameters were measured: Alpha-glutathione S-transferase (alpha-GST), alanine aminotransferase (ALT), aspartate aminotransferase (AST), glucose and serum triglycerides. At T3 and T4, alpha-GST levels were significantly higher in Group B (T3: 9.4 +/- 9.9; T4: 14.6 +/- 19.5 microg L-1) and Group C (T3: 14.2 +/- 20.8; T4: 22.4 +/- 39.3 microg L-1) compared with the patients receiving structured triglycerides (T3: 1.9 +/- 1.8; T4: 3.2 +/- 2.7 microg L-1). Whereas the mean alpha-GST-levels in structured triglycerides group always remained in the normal range, this was not the case in both other groups at T3 and T4. There were no significant differences concerning ALT, AST and glucose levels. At T3 and T4, triglyceride levels were significantly lower in Group A than in Groups B and C. Hepatic integrity was well retained with the administration of structured triglycerides, whereas both MCT/LCT emulsion and LCT emulsion caused subclinical hepatic injury.

Effects of parenteral structured lipid emulsion on modulating the inflammatory response in rats undergoing a total gastrectomy.

PubMed

Lin, Ming-Tsan; Yeh, Sung-Ling; Tsou, Shung-Sheng; Wang, Ming-Yang; Chen, Wei-Jao

2009-01-01

Structured lipid emulsion improves the nitrogen balance and is rapidly cleared from the blood of moderately catabolic patients. However, the effects of structured lipids on inflammatory reactions during major surgery are not clear. This study investigated the effect of a parenteral structured triacylglycerol emulsion on leukocyte adhesion molecule expression and inflammatory mediator production in rats undergoing a total gastrectomy. Normal rats with internal jugular catheters were assigned to three experimental groups and received total parenteral nutrition. At the same time, a total gastrectomy was performed on the experimental groups. The total parenteral nutrition solutions were isonitrogenous and identical in nutrient compositions except for differences in the composition of the fat emulsion. Group 1 received a conventional fat emulsion with long-chain triacylglycerols (LCTs), group 2 received a physical mixture of medium-chain triacylglycerols (MCTs) and LCTs (MCT/LCT), and group 3 received structured lipids composed of MCTs and LCTs (STG). Half of the rats in each respective group were sacrificed 1 d and the other half 3 d after surgery to examine the analytical parameters. Plasma cholesterol and free fatty acid levels in the STG group were lower than those in the other groups after surgery. The STG group had lower leukocyte CD11a/CD18 expressions than the MCT/LCT group 3 d after surgery, and CD11b/CD18 expressions in the STG group were lower than those in the LCT group on postoperative days. The STG group had higher monocyte chemotactic protein-1 and macrophage inflammatory protein-2 levels in peritoneal lavage fluid than did the other two groups. These results suggest that, compared with the LCT and MCT/LCT groups, rats administered STG had lower plasma lipid concentrations and leukocyte integrin expressions. In addition, STG administration may cause increased recruiting of neutrophils and monocytes at the site of injury and enhance antipathogenicity in rats undergoing a total gastrectomy.

Video Material as an Effective Educational Tool to Address Informational and Educational Needs of Cancer Patients Undergoing Radiation Therapy.

PubMed

Nathoo, Dilshad

2017-06-01

With increasing rates of cancer patients undergoing radiation therapy, the treatment itself can cause patients significant amounts of anxiety and distress. This can be attributed to the diagnosis of the disease, lack of knowledge of what radiation therapy is, expectations and management of side effects, and the lack of knowledge of supportive care for patients and their families. Providing patients with effective educational tools to meet the informational needs of cancer patients undergoing radiation therapy can empower patients and allow them to participate in treatment decision-making and their own healthcare. This discussion paper will evaluate several studies on the psychological impact of cancer patients undergoing radiation therapy and how video material can effectively meet the informational and educational needs of this patient population group.

Mitochondrial motility and vascular smooth muscle proliferation.

PubMed

Chalmers, Susan; Saunter, Christopher; Wilson, Calum; Coats, Paul; Girkin, John M; McCarron, John G

2012-12-01

Mitochondria are widely described as being highly dynamic and adaptable organelles, and their movement is thought to be vital for cell function. Yet, in various native cells, including those of heart and smooth muscle, mitochondria are stationary and rigidly structured. The significance of the differences in mitochondrial behavior to the physiological function of cells is unclear and was studied in single myocytes and intact resistance-sized cerebral arteries. We hypothesized that mitochondrial dynamics is controlled by the proliferative status of the cells. High-speed fluorescence imaging of mitochondria in live vascular smooth muscle cells shows that the organelle undergoes significant reorganization as cells become proliferative. In nonproliferative cells, mitochondria are individual (≈ 2 μm by 0.5 μm), stationary, randomly dispersed, fixed structures. However, on entering the proliferative state, mitochondria take on a more diverse architecture and become small spheres, short rod-shaped structures, long filamentous entities, and networks. When cells proliferate, mitochondria also continuously move and change shape. In the intact pressurized resistance artery, mitochondria are largely immobile structures, except in a small number of cells in which motility occurred. When proliferation of smooth muscle was encouraged in the intact resistance artery, in organ culture, the majority of mitochondria became motile and the majority of smooth muscle cells contained moving mitochondria. Significantly, restriction of mitochondrial motility using the fission blocker mitochondrial division inhibitor prevented vascular smooth muscle proliferation in both single cells and the intact resistance artery. These results show that mitochondria are adaptable and exist in intact tissue as both stationary and highly dynamic entities. This mitochondrial plasticity is an essential mechanism for the development of smooth muscle proliferation and therefore presents a novel therapeutic target against vascular disease.

Dimeric Architecture of the Hendra Virus Attachment Glycoprotein: Evidence for a Conserved Mode of Assembly▿ †

PubMed Central

Bowden, Thomas A.; Crispin, Max; Harvey, David J.; Jones, E. Yvonne; Stuart, David I.

2010-01-01

Hendra virus is a negative-sense single-stranded RNA virus within the Paramyxoviridae family which, together with Nipah virus, forms the Henipavirus genus. Infection with bat-borne Hendra virus leads to a disease with high mortality rates in humans. We determined the crystal structure of the unliganded six-bladed β-propeller domain and compared it to the previously reported structure of Hendra virus attachment glycoprotein (HeV-G) in complex with its cellular receptor, ephrin-B2. As observed for the related unliganded Nipah virus structure, there is plasticity in the Glu579-Pro590 and Lys236-Ala245 ephrin-binding loops prior to receptor engagement. These data reveal that henipaviral attachment glycoproteins undergo common structural transitions upon receptor binding and further define the structural template for antihenipaviral drug design. Our analysis also provides experimental evidence for a dimeric arrangement of HeV-G that exhibits striking similarity to those observed in crystal structures of related paramyxovirus receptor-binding glycoproteins. The biological relevance of this dimer is further supported by the positional analysis of glycosylation sites from across the paramyxoviruses. In HeV-G, the sites lie away from the putative dimer interface and remain accessible to α-mannosidase processing on oligomerization. We therefore propose that the overall mode of dimer assembly is conserved for all paramyxoviruses; however, while the geometry of dimerization is rather closely similar for those viruses that bind flexible glycan receptors, significant (up to 60°) and different reconfigurations of the subunit packing (associated with a significant decrease in the size of the dimer interface) have accompanied the independent switching to high-affinity protein receptor binding in Hendra and measles viruses. PMID:20375167

Effect of hydro mechanical coupling on natural fracture network formation in sedimentary basins

NASA Astrophysics Data System (ADS)

Ouraga, Zady; Guy, Nicolas; Pouya, Amade

2018-05-01

In sedimentary basin context, numerous phenomena, depending on the geological time span, can result in natural fracture network formation. In this paper, fracture network and dynamic fracture spacing triggered by significant sedimentation rate are studied considering mode I fracture propagation using a coupled hydro-mechanical numerical methods. The focus is put on synthetic geological structure under a constant sedimentation rate on its top. This model contains vertical fracture network initially closed and homogeneously distributed. The fractures are modelled with cohesive zone model undergoing damage and the flow is described by Poiseuille's law. The effect of the behaviour of the rock is studied and the analysis leads to a pattern of fracture network and fracture spacing in the geological layer.

The development of test methodology for testing glassy materials

NASA Technical Reports Server (NTRS)

Tucker, Dennis S.

1987-01-01

The inherent brittleness of glass invariably leads to a large variability in strength data and a time dependence in strength (i.e., static fatigue). Loading rate plays a large role in strength values. Glass is found to be weaker when supporting loads over long periods as compared to glass which undergoes rapid loading. In this instance the purpose of rapid loading is to fail the glass before any significant crack growth occurs. However, a decrease in strength occurs with a decrease in loading rate, pursuant to substantial crack extension. These properties complicate the structural design allowable for the utilization of glass components in applications such as mirrors for the Space Telescope and AXAF for Spacelab and the space station.

WIPP Intermediate Scale Borehole Test. A pretest analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Argueello, J.G.

A three-dimensional finite element structural analysis of the Intermediate Scale Borehole Test at the WIPP has been performed. The analysis provides insight into how a relatively new excavation in a creeping medium responds when introduced into an existing pillar which has been undergoing stress redistribution for 5.7 years. The stress field of the volume of material in the immediate vicinity of the borehole changes significantly when the hole is drilled. Closure of the hole is predicted to be larger in the vertical direction than in the horizontal direction, leading to an ovaling of the hole. The relatively high stresses nearmore » the hole persist even at the end of the simulation, 2 years after the hole is drilled.« less

On melt solutions for the growth of CaTiO3 crystals

NASA Astrophysics Data System (ADS)

Klimm, Detlef; Schmidt, Max; Wolff, Nora; Guguschev, Christo; Ganschow, Steffen

2018-03-01

When calcium titanate crystals are grown from stoichiometric melts, they crystallize in the cubic perovskite structure. Upon cooling to room temperature they undergo subsequent phase transitions to tetragonal and orthorhombic modifications. These phase transitions are disruptive and result in severely damaged crystals. This paper presents differential thermal analysis data for several prospective solvents, with the aim to identify a system offering the possibility to perform crystal growth of undistorted CaTiO3 crystals by crystallizing them significantly below the melting point directly in the low temperature modification. From mixtures CaF2:TiO2:CaTiO3 = 3:1:1 (molar ratio) the growth of undistorted, at least millimeter-sized CaTiO3 crystals is possible.

Effect of marital status on the outcome of patients undergoing elective or urgent coronary revascularization.

PubMed

Barbash, Israel M; Gaglia, Michael A; Torguson, Rebecca; Minha, Sa'ar; Satler, Lowell F; Pichard, Augusto D; Waksman, Ron

2013-10-01

Marriage confers various health advantages in the general population. However, the added value of marriage among patients who undergo percutaneous coronary intervention (PCI) beyond the standard cardiovascular risk factors is not clear. This study aimed to assess the effects of marital status on outcomes of patients undergoing elective or urgent PCI. Clinical observational analysis of consecutive patients undergoing elective or urgent PCI from 1993 to 2011 was performed. Patients were stratified by marital status, comparing married to unmarried patients. Clinical outcome up to 12 months was obtained by telephone contact or office visit. A total of 11,216 patients were included in the present analysis; 55% were married and 45% unmarried. Significant differences in baseline characteristics were noted, including a lower prevalence of hypertension (86% vs 88%), diabetes (34% vs 38%), and smoking (19% vs 25%) among married vs unmarried patients, respectively (P < .001). However, married patients had a higher prevalence of hypercholesterolemia and family history of coronary artery disease. Early and late major adverse cardiac event rates were significantly lower for married vs unmarried patients up to 1 year (13.3% vs 8.2%, P < .001). Married status was independently associated with improved outcome in multivariable analysis (hazard ratio 0.7, 95% CI 0.6-0.9). Married patients who undergo urgent or elective PCI have superior short- and long-term outcomes up to 1 year when compared with unmarried patients. These benefits persist after adjustment for multiple traditional cardiovascular risk factors. © 2013.

The treatment of female pattern hair loss and other applications of surgical hair restoration in women.

PubMed

Epstein, Jeffrey S

2004-05-01

In the specialty of surgical hair restoration, men comprise more than 90% of the patients treated; however, in the last few years the number of women undergoing the procedure has increased significantly. The reasons for this growth are many and include the increase in public awareness of the efficacy of hair transplantation from such sources as the media,the Internet, advertising and word of mouth. More importantly, advances in technique have significantly improved results, increasing the confidence level in women to undergo the procedure and in hair transplant specialists to offer it.

Two-dimensional correlation and codistribution spectroscopy (2DCOS and 2DCDS) analyses of time-dependent ATR IR spectra of D-glucose anomers undergoing mutarotation process in water

NASA Astrophysics Data System (ADS)

Noda, Isao

2018-05-01

Two cyclic diastereoisomeric structures, known as α- and β-anomers of D-glucose with different configurations around C1 with OH groups in axial or equitroial positions, undergo the mutarotation conversion to each other in water. Two-dimensional correlation and codistribution spectroscopy (2DCOS and 2DCDS) analyses were applied to the time-dependent ATR IR spectra of aqueous solutions of α- and β-D-glucose undergoing such mutarotation conversion. 2DCOS analysis reveals that the increase and decrease in the IR intensities after the dissolution of α- or β-D-glucose are not fully synchronized, suggesting the mutarotation of D-glucose in water is not a simple binary conversion process but a multi-step reaction involving an intermediate species with a finite and observable concentration level and lifetime. 2DCDS analysis of the time-dependent ATR IR spectra clearly demonstrated the presence of intermediate species contributing to the band positions overlapped close to bands for α- and β-D-glucose. The fact that band positions identified for the intermediate species for α- to β-D-glucose conversion are the same for the reverse reaction suggests that they arise from the same species, most likely the open-ring structure produced by the hydrolysis.

An examination of loads and responses of a wind turbine undergoing variable-speed operation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wright, A.D.; Buhl, M.L. Jr.; Bir, G.S.

1996-11-01

The National Renewable Energy Laboratory has recently developed the ability to predict turbine loads and responses for machines undergoing variable-speed operation. The wind industry has debated the potential benefits of operating wind turbine sat variable speeds for some time. Turbine system dynamic responses (structural response, resonance, and component interactions) are an important consideration for variable-speed operation of wind turbines. The authors have implemented simple, variable-speed control algorithms for both the FAST and ADAMS dynamics codes. The control algorithm is a simple one, allowing the turbine to track the optimum power coefficient (C{sub p}). The objective of this paper is tomore » show turbine loads and responses for a particular two-bladed, teetering-hub, downwind turbine undergoing variable-speed operation. The authors examined the response of the machine to various turbulent wind inflow conditions. In addition, they compare the structural responses under fixed-speed and variable-speed operation. For this paper, they restrict their comparisons to those wind-speed ranges for which limiting power by some additional control strategy (blade pitch or aileron control, for example) is not necessary. The objective here is to develop a basic understanding of the differences in loads and responses between the fixed-speed and variable-speed operation of this wind turbine configuration.« less

Encompassing receptor flexibility in virtual screening using ensemble docking-based hybrid QSAR: discovery of novel phytochemicals for BACE1 inhibition.

PubMed

Chakraborty, Sandipan; Ramachandran, Balaji; Basu, Soumalee

2014-10-01

Mimicking receptor flexibility during receptor-ligand binding is a challenging task in computational drug design since it is associated with a large increase in the conformational search space. In the present study, we have devised an in silico design strategy incorporating receptor flexibility in virtual screening to identify potential lead compounds as inhibitors for flexible proteins. We have considered BACE1 (β-secretase), a key target protease from a therapeutic perspective for Alzheimer's disease, as the highly flexible receptor. The protein undergoes significant conformational transitions from open to closed form upon ligand binding, which makes it a difficult target for inhibitor design. We have designed a hybrid structure-activity model containing both ligand based descriptors and energetic descriptors obtained from molecular docking based on a dataset of structurally diverse BACE1 inhibitors. An ensemble of receptor conformations have been used in the docking study, further improving the prediction ability of the model. The designed model that shows significant prediction ability judged by several statistical parameters has been used to screen an in house developed 3-D structural library of 731 phytochemicals. 24 highly potent, novel BACE1 inhibitors with predicted activity (Ki) ≤ 50 nM have been identified. Detailed analysis reveals pharmacophoric features of these novel inhibitors required to inhibit BACE1.

The effects of the covalent attachment of 3-(4-hydroxy-3,5-di-tert-butylphenyl) propyl amine to glutaraldehyde pretreated bovine pericardium on structural degeneration, oxidative modification, and calcification of rat subdermal implants.

PubMed

Christian, Abigail J; Alferiev, Ivan S; Connolly, Jeanne M; Ischiropoulos, Harry; Levy, Robert J

2015-07-01

Bioprosthetic heart valves (BHV) fabricated from glutaraldehyde pretreated heterograft materials, porcine aortic valves or bovine pericardium (BP), are widely used in cardiac surgery. BHV progressively fail in clinical use due to structural degeneration. Previously we reported that dityrosine, an oxidized amino acid, was present in failed clinical BP-BHV explants; unimplanted BP had no detectable dityrosine. In the same studies BP were demonstrated in vitro to be susceptible to oxidative damage, that could be mitigated with BP covalently modified with the antioxidant, 3-(4-hydroxy-3,5-di-tert-butylphenyl)propyl amine (DBP). The present studies compared in rat subdermal implants glutaraldehyde pretreated BP to BP modified with either DBP or the chemical reactions used to link DBP. All BP explants regardless of DBP demonstrated reduced hydroxyproline and increased digestibility by collagenase. However, the DBP-BP explants showed significant inhibition of reduced explant shrink temperatures (an index of crosslinking) as compared with control BP. Significant mitigation of calcification was observed in both the BP-DBP and chemically modified explants as compared with BP. Dityrosine was not detectable in the 90 day explants. It is concluded that rat subdermal BP implants undergo both calcific and noncalcific structural degeneration, but without the formation of dityrosine, unlike clinical BP explants. © 2014 Wiley Periodicals, Inc.

The effects of the covalent attachment of 3-(4-hydroxy-3,5-di-tert-butylphenyl)propyl amine to glutaraldehyde pre-treated bovine pericardium on structural degeneration, oxidative modification and calcification of rat subdermal implants

PubMed Central

Christian, Abigail J.; Alferiev, Ivan S.; Connolly, Jeanne M.; Ischiropoulos, Harry; Levy, Robert J.

2014-01-01

Bioprosthetic heart valves (BHV) fabricated from glutaraldehyde pretreated heterograft materials, porcine aortic valves or bovine pericardium (BP), are widely used in cardiac surgery. BHV progressively fail in clinical use due to structural degeneration. Previously we reported that dityrosine, an oxidized amino acid, was present in failed clinical BP-BHV explants; unimplanted BP had no detectable dityrosine. In the same studies BP were demonstrated in vitro to be susceptible to oxidative damage, that could be mitigated with BP covalently modified with the antioxidant, 3-(4-hydroxy-3,5-di-tert-butylphenyl)propyl amine (DBP). The present studies compared in rat subdermal implants glutaraldehyde pretreated BP to BP modified with either DBP or the chemical reactions used to link DBP. All BP explants regardless of DBP demonstrated reduced hydroxyproline and increased digestibility by collagenase. However, the DBP-BP explants showed significant inhibition of reduced explant shrink temperatures (an index of crosslinking) compared to control BP. Significant mitigation of calcification was observed in both the BP-DBP and chemically modified explants compared to BP. Dityrosine was not detectable in the 90 day explants. It is concluded that rat subdermal BP implants undergo both calcific and non-calcific structural degeneration, but without the formation of dityrosine, unlike clinical BP explants. PMID:25546235

Planetesimal formation in self-gravitating discs - dust trapping by vortices

NASA Astrophysics Data System (ADS)

Gibbons, P. G.; Mamatsashvili, G. R.; Rice, W. K. M.

2015-11-01

The mechanism through which metre-sized boulders grow to km-sized planetesimals in protoplanetary discs is a subject of active research, since it is critical for planet formation. To avoid spiralling into the protostar due to aerodynamic drag, objects must rapidly grow from cm-sized pebbles, which are tightly coupled to the gas, to large boulders of 1-100 m in diameter. It is already well known that overdensities in the gaseous component of the disc provide potential sites for the collection of solids, and that significant density structures in the gaseous component of the disc (e.g. spiral density waves) can trap solids efficiently enough for the solid component of the disc to undergo further gravitational collapse due to their own self-gravity. In this work, we employ the PENCIL CODE to conduct local shearing sheet simulations of massive self-gravitating protoplanetary discs, to study the effect of anticyclonic transient vortices, or eddies, on the evolution of solids in these discs. We find that these types of structures are extremely efficient at concentrating small and intermediate-sized dust particles with friction times comparable to, or less than, the local orbital period of the disc. This can lead to significant over-densities in the solid component of the disc, with density enhancements comparable to, and even higher, than those within spiral density waves; increasing the rate of gravitational collapse of solids into bound structures.

Severity of chronic obstructive pulmonary disease is associated with adverse outcomes in patients undergoing elective abdominal aortic aneurysm repair.

PubMed

Stone, David H; Goodney, Philip P; Kalish, Jeffrey; Schanzer, Andres; Indes, Jeffrey; Walsh, Daniel B; Cronenwett, Jack L; Nolan, Brian W

2013-06-01

Although chronic obstructive pulmonary disease (COPD) has been implicated as a risk factor for abdominal aortic aneurysm (AAA) rupture, its effect on surgical repair is less defined. Consequently, variation in practice persists regarding patient selection and surgical management. The purpose of this study was to analyze the effect of COPD on patients undergoing AAA repair. We reviewed a prospective regional registry of 3455 patients undergoing elective open AAA repair (OAR) and endovascular AAA repair (EVAR) from 23 centers in the Vascular Study Group of New England from 2003 to 2011. COPD was categorized as none, medical (medically treated but not oxygen [O2]-dependent), and O2-dependent. End points included in-hospital death, pulmonary complications, major postoperative adverse events (MAEs), extubation in the operating room, and 5-year survival. Survival was determined using life-table analysis based on the Social Security Death Index. Predictors of in-hospital and long-term mortality were determined by multivariate logistic regression and Cox proportional hazards analysis. During the study interval, 2043 patients underwent EVAR and 1412 patients underwent OAR with a nearly equal prevalence of COPD (35% EVAR vs 36% OAR). O2-dependent COPD (4%) was associated with significantly increased in-hospital mortality, pulmonary complications, and MAE and was also associated with significantly decreased extubation in the operating room among patients undergoing both EVAR and OAR. Five-year survival was significantly diminished among all patients undergoing AAA repair with COPD (none, 78%; medical, 72%; O2-dependent, 42%; P < .001). By multivariate analysis, O2-dependent COPD was independently associated with in-hospital mortality (odds ratio 2.02, 95% confidence interval, 1.0-4.0; P = .04) and diminished 5-year survival (hazard ratio, 3.02; 95% confidence interval, 2.2-4.1; P < .001). Patients with O2-dependent COPD undergoing AAA repair suffer increased pulmonary complications, overall MAE, and diminished long-term survival. This must be carefully factored into the risk-benefit analysis before recommending elective AAA repair in these patients. Copyright © 2013 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

Outcomes after elective abdominal aortic aneurysm repair in obese versus nonobese patients.

PubMed

Locham, Satinderjit; Rizwan, Muhammad; Dakour-Aridi, Hanaa; Faateh, Muhammad; Nejim, Besma; Malas, Mahmoud

2018-06-07

Obesity is a worldwide epidemic, particularly in Western society. It predisposes surgical patients to an increased risk of adverse outcomes. The aim of our study was to use a nationally representative vascular database and to compare in-hospital outcomes in obese vs nonobese patients undergoing elective open aortic repair (OAR) and endovascular aneurysm repair (EVAR). All patients undergoing elective abdominal aortic aneurysm repair were identified in the Vascular Quality Initiative database (2003-2017). Obesity was defined as body mass index ≥30 kg/m 2 . Univariable (Student t-test and χ 2  test) and multivariable (logistic regression) analyses were implemented to compare in-hospital mortality and any major complications (wound infection, renal failure, and cardiopulmonary failure) in obese vs nonobese patients. We identified a total of 33,082 patients undergoing elective OAR (nonobese, n = 4605 [72.4%]; obese, n = 1754 [27.6%]) and EVAR (nonobese, n = 18,338 [68.6%]; obese, n = 8385 [31.4%]). Obese patients undergoing OAR and EVAR were relatively younger compared with nonobese patients (mean age [standard deviation], 67.55 [8.26] years vs 70.27 [8.30] years and 71.06 [8.22] years vs 74.55 [8.55] years), respectively; (both P < .001). Regardless of approach, obese patients had slightly longer operative time (OAR, 259.02 [109.97] minutes vs 239.37 [99.78] minutes; EVAR, 138.27 [70.64] minutes vs 134.34 [69.98] minutes) and higher blood loss (OAR, 2030 [1823] mL vs 1619 [1642] mL; EVAR, 228 [354] mL vs 207 [312] mL; both P < .001). There was no significant difference in mortality between the two groups undergoing OAR and EVAR (OAR, 2.9% vs 3.2% [P = .50]; EVAR, 0.5% vs 0.6% [P = .76]). On multivariable analysis, obese patients undergoing OAR had 33% higher odds of renal failure (adjusted odds ratio [OR], 1.33; 95% confidence interval [CI], 1.09-1.63; P = .006) and 75% higher odds of wound infections (adjusted OR, 1.75; 95% CI, 1.11-2.76; P = .02) compared with nonobese patients. However, in patients undergoing EVAR, no association was seen between obesity and any major complications. A significant interaction was found between obesity and surgical approach in the event of renal failure, in which obese patients undergoing OAR had significantly higher odds of renal failure compared with those in the EVAR group (OR interaction , 1.36; 95% CI, 1.05-1.75; P = .02). Using a large nationally representative database, we demonstrated an increased risk of renal failure and wound infections in obese patients undergoing OAR compared with nonobese patients. On the other hand, obesity did not seem to increase the odds of major adverse outcomes in patients undergoing EVAR. Further long-term prospective studies are needed to verify the effects of obesity after abdominal aortic aneurysm repair and the implications of these findings in clinical decision-making. Copyright © 2018 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Male factor infertility and lack of openness about infertility as risk factors for depressive symptoms in males undergoing assisted reproductive technology treatment in Italy.

PubMed

Babore, Alessandra; Stuppia, Liborio; Trumello, Carmen; Candelori, Carla; Antonucci, Ivana

2017-04-01

To investigate the association between male factor infertility and openness to discussing assisted reproductive technology (ART) treatment with levels of depression among men undergoing infertility treatment. Cross-sectional. Not applicable. Three hundred forty participants (170 men and their partners) undergoing ART treatments. Administration of a set of questionnaires. Depressive symptoms were detected by means of the Zung Depression Self-Rating Scale. Participants' willingness to share their infertility treatment experience with other people was assessed by means of self-report questionnaires. In this study, 51.8% of males chose not to discuss their ART treatments with people other than their partner. In addition, the decision to discuss or not discuss the ART treatments with others was significantly associated with men's depressive symptoms. Male factor infertility was significantly associated with depression when considered together with the decision not to discuss ART treatments with others. A general disposition characterized by a lack of openness with others seemed to be a significant predictor of depression. There is a need for routine fertility care to pay greater attention to men's emotional needs. Before commencing reproductive treatment, male patients may benefit from undergoing routine screening for variables (i.e., male factor infertility and openness to others about ART) that may affect their risk of depression. Copyright © 2017 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

The Effect of Music on Anxiety and Cardiovascular Indices in Patients Undergoing Coronary Artery Bypass Graft: A Randomized Controlled Trial.

PubMed

Heidari, Saeide; Babaii, Atye; Abbasinia, Mohammad; Shamali, Mahdi; Abbasi, Mohammad; Rezaei, Mahboobe

2015-12-01

The instability of cardiovascular indices and anxiety disorders are common among patients undergoing coronary artery bypass graft (CABG) and could interfere with their recovery. Therefore, improving the cardiovascular indices and anxiety is essential. This study aimed to investigate the effect of music therapy on anxiety and cardiovascular indices in patients undergoing CABG. In this randomized controlled trial, 60 patients hospitalized in the cardiovascular surgical intensive care unit of Shahid Beheshti Hospital in Qom city, Iran, in 2013 were selected using a consecutive sampling method and randomly allocated into the experimental and control groups. In the experimental group, patients received 30 minutes of light music, whereas in the control group, patients had 30 minutes of rest in bed. The cardiovascular indices and anxiety were measured immediately before, immediately after and half an hour after the study. Data were analyzed using the chi-square test and repeated measures analysis of variance. Compared to the immediately before intervention, the mean anxiety scores immediately after and 30 minutes after the intervention were significantly lower in the experimental group (P < 0.037) while it did not significantly change in the control group. However, there were no significant differences regarding the cardiovascular indices in the three consecutive measurements (P > 0.05). Music therapy is effective in decreasing anxiety among patients undergoing CABG. However, the intervention was not effective on cardiovascular indices. Music can effectively be used as a non-pharmacological method to manage anxiety after CABG.

Structured methods for identifying and correcting potential human errors in aviation operations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nelson, W.R.

1997-10-01

Human errors have been identified as the source of approximately 60% of the incidents and accidents that occur in commercial aviation. It can be assumed that a very large number of human errors occur in aviation operations, even though in most cases the redundancies and diversities built into the design of aircraft systems prevent the errors from leading to serious consequences. In addition, when it is acknowledged that many system failures have their roots in human errors that occur in the design phase, it becomes apparent that the identification and elimination of potential human errors could significantly decrease the risksmore » of aviation operations. This will become even more critical during the design of advanced automation-based aircraft systems as well as next-generation systems for air traffic management. Structured methods to identify and correct potential human errors in aviation operations have been developed and are currently undergoing testing at the Idaho National Engineering and Environmental Laboratory (INEEL).« less

Spontaneous scalarization with an extremely massive field and heavy neutron stars

NASA Astrophysics Data System (ADS)

Morisaki, Soichiro; Suyama, Teruaki

2017-10-01

We investigate the internal structure and the mass-radius relation of neutron stars in a recently proposed scalar-tensor theory dubbed asymmetron in which a massive scalar field undergoes spontaneous scalarization inside neutron stars. We focus on the case where the Compton wavelength is shorter than 10 km, which has not been investigated in the literature. By solving the modified Einstein equations, either purely numerically or by partially using a semianalytic method, we find that not only the weakening of gravity by spontaneous scalarization but also the scalar force affect the internal structure significantly in the massive case. We also find that the maximum mass of neutron stars is larger for certain parameter sets than that in general relativity and reaches 2 M⊙ even if the effect of strange hadrons is taken into account. There is even a range of parameters where the maximum mass of neutron stars largely exceeds the threshold that violates the causality bound in general relativity.

Longitudinal Changes in White Matter Fractional Anisotropy in Adult-Onset Niemann-Pick Disease Type C Patients Treated with Miglustat.

PubMed

Bowman, Elizabeth A; Velakoulis, Dennis; Desmond, Patricia; Walterfang, Mark

2018-01-01

Niemann-Pick disease type C (NPC) is a rare neurometabolic disorder resulting in impaired intracellular lipid trafficking. The only disease-modifying treatment currently available is miglustat, an iminosugar that inhibits the accumulation of lipid metabolites in neurons and other cells. This longitudinal diffusion tensor imaging (DTI) study examined how the rate of white matter change differed between treated and non-treated adult-onset NPC patient groups. Nine adult-onset NPC patients (seven undergoing treatment with miglustat, two not treated) underwent DTI neuroimaging. Rates of change in white matter structure as indexed by Tract-Based Spatial Statistics (TBSS) of fractional anisotropy were compared between treated and untreated patients. Treated patients were found to have a significantly slower rate of white matter change in the corticospinal tracts, the thalamic radiation and the inferior longitudinal fasciculus. This is further evidence that miglustat treatment may have a protective effect on white matter structure in the adult-onset form of the disease.

Carbon Nanotubes on Titanium Substrates for Stray Light Suppression

NASA Technical Reports Server (NTRS)

Hagopian, John; Getty, Stephanie; Quijada, Manuel

2011-01-01

A method has been developed for growing carbon nanotubes on a titanium substrate, which makes the nano tubes ten times blacker than the current state-of-the-art paints in the visible to near infrared. This will allow for significant improvement of stray light performance in scientific instruments, or any other optical system. Because baffles, stops, and tubes used in scientific observations often undergo loads such as vibration, it is critical to develop this surface treatment on structural materials. This innovation optimizes the carbon nano - tube growth for titanium, which is a strong, lightweight structural material suitable for spaceflight use. The steps required to grow the nanotubes require the preparation of the surface by lapping, and the deposition of an iron catalyst over an alumina stiction layer by e-beam evaporation. In operation, the stray light controls are fabricated, and nanotubes (multi-walled 100 microns in length) are grown on the surface. They are then installed in the instruments or other optical devices.

Counting Active Sites on Titanium Oxide-Silica Catalysts for Hydrogen Peroxide Activation through In Situ Poisoning with Phenylphosphonic Acid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eaton, Todd R.; Boston, Andrew M.; Thompson, Anthony B.

2015-06-04

Quantifying specific active sites in supported catalysts improves our understanding and assists in rational design. Supported oxides can undergo significant structural changes as surface densities increase from site-isolated cations to monolayers and crystallites, which changes the number of kinetically relevant sites. Herein, TiO x domains are titrated on TiO x–SiO 2 selectively with phenylphosphonic acid (PPA). An ex situ method quantifies all fluid-accessible TiO x, whereas an in situ titration during cis-cyclooctene epoxidation provides previously unavailable values for the number of tetrahedral Ti sites on which H 2O 2 activation occurs. We use this method to determine the active sitemore » densities of 22 different catalysts with different synthesis methods, loadings, and characteristic spectra and find a single intrinsic turnover frequency for cis-cyclooctene epoxidation of (40±7) h -1. This simple method gives molecular-level insight into catalyst structure that is otherwise hidden when bulk techniques are used.« less

Role of H1 Linker Histones in Mammalian Development and Stem Cell Differentiation

PubMed Central

Pan, Chenyi; Fan, Yuhong

2016-01-01

H1 linker histones are key chromatin architectural proteins facilitating the formation of higher order chromatin structures. The H1 family constitutes the most heterogeneous group of histone proteins, with eleven non-allelic H1 variants in mammals. H1 variants differ in their biochemical properties and exhibit significant sequence divergence from one another, yet most of them are highly conserved during evolution from mouse to human. H1 variants are differentially regulated during development and their cellular compositions undergo dramatic changes in embryogenesis, gametogenesis, tissue maturation and cellular differentiation. As a group, H1 histones are essential for mouse development and proper stem cell differentiation. Here we summarize our current knowledge on the expression and functions of H1 variants in mammalian development and stem cell differentiation. Their diversity, sequence conservation, complex expression and distinct functions suggest that H1s mediate chromatin reprogramming and contribute to the large variations and complexity of chromatin structure and gene expression in the mammalian genome. PMID:26689747

Basic science and surgical treatment options for articular cartilage injuries of the knee.

PubMed

Tetteh, Elizabeth S; Bajaj, Sarvottam; Ghodadra, Neil S

2012-03-01

The complex structure of articular cartilage allows for diverse knee function throughout range of motion and weight bearing. However, disruption to the structural integrity of the articular surface can cause significant morbidity. Due to an inherently poor regenerative capacity, articular cartilage defects present a treatment challenge for physicians and therapists. For many patients, a trial of nonsurgical treatment options is paramount prior to surgical intervention. In instances of failed conservative treatment, patients can undergo an array of palliative, restorative, or reparative surgical procedures to treat these lesions. Palliative methods include debridement and lavage, while restorative techniques include marrow stimulation. For larger lesions involving subchondral bone, reparative procedures such as osteochondral grafting or autologous chondrocyte implantation are considered. Clinical success not only depends on the surgical techniques but also requires strict adherence to rehabilitation guidelines. The purpose of this article is to review the basic science of articular cartilage and to provide an overview of the procedures currently performed at our institution for patients presenting with symptomatic cartilage lesions.

[Ultrastructure of the intima of human pial arteries in arterial hypertension].

PubMed

Chertok, V M; Kotsiuba, A E; Babich, E V

2009-01-01

Ultrastructure of the intima of human pial arteries obtained from 5 male cadavers of practically healthy individuals and from 8 cadavers of the patients with the intravitally diagnosed grade I arterial hypertension (AH) was studied by scanning and transmission electron microscopy. AH was found to be associated with the remodeling of the intimal structural elements in the pial arteries. In most arteries, the changes were detected in the microrelief of the luminal surface and in the permeability of the vascular endothelial lining and of the subendothelial layer. During this remodeling, some endothelial cells were found in the state of structural and functional adaptation to the elevated arterial pressure, while the others were undergoing the dystrophic changes. The latter include the cells containing lipid inclusions, as well as the endothelial cells presumably in the state of apoptosis. The destruction of the intercellular junctions, the disturbances in the endothelium permeability contributed to the development of subendothelial layer edema, resulting in its significant thickening. This layer became looser and contained abundant collagen fibrils.

Who Seeks Treatment When Medicine Opens the Door to Pathological Gambling Patients-Psychiatric Comorbidity and Heavy Predominance of Online Gambling.

PubMed

Håkansson, Anders; Mårdhed, Emma; Zaar, Mats

2017-01-01

Few studies have assessed treatment-seeking behavior and patient characteristics in pathological gambling focusing on psychiatric comorbidity, particularly in a setting of heavy exposure to online gambling. This study aimed to address patient characteristics in a novel health care-based treatment modality for pathological gambling, including potential associations between gambling types, psychiatric comorbidity, and gender. All patients undergoing structured assessment between January 2016 and April 2017 were included ( N  = 106), and patient records were reviewed for cooccurring psychiatric disorders and types of problem games. Eighty percent were men, and 58% received a psychiatric disorder apart from pathological gambling. Problematic gambling on online casino and online sports betting represented 84% of patients. Non-substance-related psychiatric comorbidity was significantly associated with female gender. Online gambling is more clearly predominating in this setting than in studies from other countries. High rates of comorbidity call for structured psychiatric assessment in problem gambling, with a particular focus on female patients with pathological gambling.

Effect of rolling on phase composition and microhardness of austenitic steels with different stacking-fault energies

NASA Astrophysics Data System (ADS)

Melnikov, Eugene; Astafurova, Elena; Maier, Galina; Moskvina, Valentina

2017-12-01

The influence of multi-pass cold rolling on the phase composition and microhardness of austenitic Fe-18Cr-9Ni-0.21C, Fe-18Cr-9Ni-0.5Ti-0.08C, Fe-17Cr-13Ni-3Mo-0.01C (in wt %) steels with different stacking fault energies was studied. The metastable Fe-18Cr-9Ni-0.5Ti-0.08C steel undergoes γ → α' phase transformations during rolling, the volume fraction of strain-induced α'-martensite in steel structure is increased with increasing strain. Metastable austenite Fe-18Cr-9Ni-0.21C steel does not undergo the formation of an appreciable amount of strain-induced α'-martensite under rolling, but the magnetophase analysis reveals a small amount of ferrite phase in the structure of steel after rolling. The structure of stable Fe-17Cr-13Ni-3Mo-0.01C steel remains austenitic independently under strain. Investigations of microhardness of the steels show that their values are increased with strain and are dependent on propensity of steels to strain-induced martensitic transformation.

Time-Resolved Small-Angle X-ray Scattering Reveals Millisecond Transitions of a DNA Origami Switch.

PubMed

Bruetzel, Linda K; Walker, Philipp U; Gerling, Thomas; Dietz, Hendrik; Lipfert, Jan

2018-04-11

Self-assembled DNA structures enable creation of specific shapes at the nanometer-micrometer scale with molecular resolution. The construction of functional DNA assemblies will likely require dynamic structures that can undergo controllable conformational changes. DNA devices based on shape complementary stacking interactions have been demonstrated to undergo reversible conformational changes triggered by changes in ionic environment or temperature. An experimentally unexplored aspect is how quickly conformational transitions of large synthetic DNA origami structures can actually occur. Here, we use time-resolved small-angle X-ray scattering to monitor large-scale conformational transitions of a two-state DNA origami switch in free solution. We show that the DNA device switches from its open to its closed conformation upon addition of MgCl 2 in milliseconds, which is close to the theoretical diffusive speed limit. In contrast, measurements of the dimerization of DNA origami bricks reveal much slower and concentration-dependent assembly kinetics. DNA brick dimerization occurs on a time scale of minutes to hours suggesting that the kinetics depend on local concentration and molecular alignment.

Simultaneous structure-activity studies and arming of natural products by C-H amination reveal cellular targets of eupalmerin acetate.

PubMed

Li, Jing; Cisar, Justin S; Zhou, Cong-Ying; Vera, Brunilda; Williams, Howard; Rodríguez, Abimael D; Cravatt, Benjamin F; Romo, Daniel

2013-06-01

Natural products have a venerable history of, and enduring potential for the discovery of useful biological activity. To fully exploit this, the development of chemical methodology that can functionalize unique sites within these complex structures is highly desirable. Here, we describe the use of rhodium(II)-catalysed C-H amination reactions developed by Du Bois to carry out simultaneous structure-activity relationship studies and arming (alkynylation) of natural products at 'unfunctionalized' positions. Allylic and benzylic C-H bonds in the natural products undergo amination while olefins undergo aziridination, and tertiary amine-containing natural products are converted to amidines by a C-H amination-oxidation sequence or to hydrazine sulfamate zwitterions by an unusual N-amination. The alkynylated derivatives are ready for conversion into cellular probes that can be used for mechanism-of-action studies. Chemo- and site-selectivity was studied with a diverse library of natural products. For one of these-the marine-derived anticancer diterpene, eupalmerin acetate-quantitative proteome profiling led to the identification of several protein targets in HL-60 cells, suggesting a polypharmacological mode of action.

Simultaneous structure-activity studies and arming of natural products by C-H amination reveal cellular targets of eupalmerin acetate

NASA Astrophysics Data System (ADS)

Li, Jing; Cisar, Justin S.; Zhou, Cong-Ying; Vera, Brunilda; Williams, Howard; Rodríguez, Abimael D.; Cravatt, Benjamin F.; Romo, Daniel

2013-06-01

Natural products have a venerable history of, and enduring potential for the discovery of useful biological activity. To fully exploit this, the development of chemical methodology that can functionalize unique sites within these complex structures is highly desirable. Here, we describe the use of rhodium(II)-catalysed C-H amination reactions developed by Du Bois to carry out simultaneous structure-activity relationship studies and arming (alkynylation) of natural products at ‘unfunctionalized’ positions. Allylic and benzylic C-H bonds in the natural products undergo amination while olefins undergo aziridination, and tertiary amine-containing natural products are converted to amidines by a C-H amination-oxidation sequence or to hydrazine sulfamate zwitterions by an unusual N-amination. The alkynylated derivatives are ready for conversion into cellular probes that can be used for mechanism-of-action studies. Chemo- and site-selectivity was studied with a diverse library of natural products. For one of these—the marine-derived anticancer diterpene, eupalmerin acetate—quantitative proteome profiling led to the identification of several protein targets in HL-60 cells, suggesting a polypharmacological mode of action.

Mcl-1–Bim complexes accommodate surprising point mutations via minor structural changes

PubMed Central

Fire, Emiko; Gullá, Stefano V; Grant, Robert A; Keating, Amy E

2010-01-01

Mcl-1 is an antiapoptotic Bcl-2-family protein that protects cells against death. Structures of Mcl-1, and of other anti-apoptotic Bcl-2 proteins, reveal a surface groove into which the α-helical BH3 regions of certain proapoptotic proteins can bind. Despite high overall structural conservation, differences in this groove afford binding specificity that is important for the mechanism of Bcl-2 family function. We report the crystal structure of human Mcl-1 bound to a BH3 peptide derived from human Bim and the structures for three complexes that accommodate large physicochemical changes at conserved Bim sites. The mutations had surprisingly modest effects on complex stability, and the structures show that Mcl-1 can undergo small changes to accommodate the mutant ligands. For example, a shift in a leucine side chain fills a hole left by an isoleucine-to-alanine mutation at the first hydrophobic buried position of Bim BH3. Larger changes are also observed, with shifting of helix α3 accommodating an isoleucine-to-tyrosine mutation at this same position. We surveyed the variation in available Mcl-1 and Bcl-xL structures and observed moderate flexibility that is likely critical for facilitating interactions of diverse BH3-only proteins with Mcl-1. With the antiapoptotic Bcl-2 family members attracting significant attention as therapeutic targets, these structures contribute to our growing understanding of how specificity is achieved and can help to guide the design of novel inhibitors that target Mcl-1. PMID:20066663

Exploring the relationships between International Classification of Functioning, Disability and Health (ICF) constructs of Impairment, Activity Limitation and Participation Restriction in people with osteoarthritis prior to joint replacement.

PubMed

Pollard, Beth; Johnston, Marie; Dieppe, Paul

2011-05-16

The International Classification of Functioning, Disability and Health (ICF) proposes three main constructs, impairment (I), activity limitation (A) and participation restriction (P). The ICF model allows for all paths between the constructs to be explored, with significant paths likely to vary for different conditions. The relationships between I, A and P have been explored in some conditions but not previously in people with osteoarthritis prior to joint replacement. The aim of this paper is to examine these relationships using separate measures of each construct and structural equation modelling. A geographical cohort of 413 patients with osteoarthritis about to undergo hip and knee joint replacement completed the Aberdeen measures of Impairment, Activity Limitation and Participation Restriction (Ab-IAP). Confirmatory factor analysis was used to test the three factor (I, A, P) measurement model. Structural equation modelling was used to explore the I, A and P pathways in the ICF model. There was support from confirmatory factor analysis for the three factor I, A, P measurement model. The structural equation model had good fit [S-B Chi-square = 439.45, df = 149, CFI robust = 0.91, RMSEA robust = 0.07] and indicated significant pathways between I and A (standardised coefficient = 0.76 p < 0.0001) and between A and P (standardised coefficient = 0.75 p < 0.0001). However, the path between I and P was not significant (standardised coefficient = 0.01). The significant pathways suggest that treatments and interventions aimed at reducing impairment, such as joint replacement, may only affect P indirectly, through A, however, longitudinal data would be needed to establish this.

Is low serum albumin associated with postoperative complications in patients undergoing cardiac surgery?

PubMed

Karas, Pamela L; Goh, Sean L; Dhital, Kumud

2015-12-01

A best evidence topic was written according to a structured protocol. The clinical question investigated was: is low serum albumin associated with postoperative complications in patients undergoing cardiac surgery? There were 62 papers retrieved using the reported search strategy. Of these, 12 publications embodied the best evidence to answer this clinical question. The authors, journal, date and country of the publication, patient group investigated, study design, relevant outcomes and results of these papers were tabulated. This paper includes a total of 12 589 patients, and of the papers reviewed, 4 were level 3 and 8 level 4. Each of the publications reviewed and compared either all or some of the following postoperative complications: mortality, postoperative bleeding requiring reoperation, prolonged hospital stay and ventilatory support, infection, liver dysfunction, delirium and acute kidney injury (AKI). Of the studies that examined postoperative mortality, all except for three established a significant multivariate association with low preoperative albumin level. Some scepticism is required in accepting other results that were only present in univariate analysis. While three studies examined multiple levels of serum albumin, most dichotomized the serum albumin levels into normal and abnormal groups. This led to differing classifications of hypoalbuminaemia, ranging from less than 2.5 to 4.0 g/dl. The available evidence, however, suggests that low preoperative serum albumin level in patients undergoing cardiac surgery is associated with the following: (i) increased risk of mortality after surgery and (ii) greater incidence of postoperative morbidity. While the evidence supports the use of preoperative albumin in assessing post-cardiac surgery complications, a specific level of albumin considered to be abnormal cannot be concluded from this review. © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Endemic infections are always possible on regular networks

NASA Astrophysics Data System (ADS)

Del Genio, Charo I.; House, Thomas

2013-10-01

We study the dependence of the largest component in regular networks on the clustering coefficient, showing that its size changes smoothly without undergoing a phase transition. We explain this behavior via an analytical approach based on the network structure, and provide an exact equation describing the numerical results. Our work indicates that intrinsic structural properties always allow the spread of epidemics on regular networks.

Syntheses, structural variants and characterization of AInM′S{sub 4} (A=alkali metals, Tl; M′ = Ge, Sn) compounds; facile ion-exchange reactions of layered NaInSnS{sub 4} and KInSnS{sub 4} compounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yohannan, Jinu P.; Vidyasagar, Kanamaluru, E-mail: kvsagar@iitm.ac.in

Ten AInM′S{sub 4} (A=alkali metals, Tl; M′= Ge, Sn) compounds with diverse structure types have been synthesized and characterized by single crystal and powder X-ray diffraction and a variety of spectroscopic methods. They are wide band gap semiconductors. KInGeS{sub 4}(1-β), RbInGeS{sub 4}(2), CsInGeS{sub 4}(3-β), TlInGeS{sub 4}(4-β), RbInSnS{sub 4}(8-β) and CsInSnS{sub 4}(9) compounds with three-dimensional BaGa{sub 2}S{sub 4} structure and CsInGeS{sub 4}(3-α) and TlInGeS{sub 4}(4-α) compounds with a layered TlInSiS{sub 4} structure have tetrahedral [InM′S{sub 4}]{sup −} frameworks. On the other hand, LiInSnS{sub 4}(5) with spinel structure and NaInSnS{sub 4}(6), KInSnS{sub 4}(7), RbInSnS{sub 4}(8-α) and TlInSnS{sub 4}(10) compounds with layered structuremore » have octahedral [InM′S{sub 4}]{sup −} frameworks. NaInSnS{sub 4}(6) and KInSnS{sub 4}(7) compounds undergo facile topotactic ion-exchange, at room temperature, with various mono-, di- and tri-valent cations in aqueous medium to give rise to metastable layered phases. - Graphical abstract: NaInSnS{sub 4} and KInSnS{sub 4} compounds undergo, in aqueous medium at room temperature, facile topotactic ion-exchange with mono, di and trivalent cations. Display Omitted - Highlights: • Ten AInM′S{sub 4} compounds with diverse structure types were synthesized. • They are wide band gap semiconductors. • NaInSnS{sub 4} and KInSnS{sub 4} compounds undergo facile topotactic ion-exchange at room temperature.« less

Practice variations in voice treatment selection following vocal fold mucosal resection.

PubMed

Moore, Jaime E; Rathouz, Paul J; Havlena, Jeffrey A; Zhao, Qianqian; Dailey, Seth H; Smith, Maureen A; Greenberg, Caprice C; Welham, Nathan V

2016-11-01

To characterize initial voice treatment selection following vocal fold mucosal resection in a Medicare population. Retrospective analysis of a large, nationally representative Medicare claims database. Patients with > 12 months of continuous Medicare coverage who underwent a leukoplakia- or cancer-related vocal fold mucosal resection (index) procedure during calendar years 2004 to 2009 were studied. The primary outcome of interest was receipt of initial voice treatment (thyroplasty, vocal fold injection, or speech therapy) following the index procedure. We evaluated the cumulative incidence of each postindex treatment type, treating the other treatment types as competing risks, and further evaluated postindex treatment utilization using the proportional hazards model for the subdistribution of a competing risk. Patient age, sex, and Medicaid eligibility were used as predictors. A total of 2,041 patients underwent 2,427 index procedures during the study period. In 14% of cases, an initial voice treatment event was identified. Women were significantly less likely to receive surgical or behavioral treatment compared to men. From age 65 to 75 years, the likelihood of undergoing surgical treatment increased significantly with each 5-year age increase; after age 75 years, the likelihood of undergoing either surgical or behavioral treatment decreased significantly every 5 years. Patients with low socioeconomic status were significantly less likely to undergo speech therapy. The majority of Medicare patients do not undergo voice treatment following vocal fold mucosal resection. Further, the treatments analyzed here appear disproportionally utilized based on patient sex, age, and socioeconomic status. Additional research is needed to determine whether these observations reflect clinically explainable differences or disparities in care. 2c. Laryngoscope, 126:2505-2512, 2016. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

Practice variations in voice treatment selection following vocal fold mucosal resection

PubMed Central

Moore, Jaime E.; Rathouz, Paul J.; Havlena, Jeffrey A.; Zhao, Qianqian; Dailey, Seth H.; Smith, Maureen A.; Greenberg, Caprice C.; Welham, Nathan V.

2016-01-01

Objective To characterize initial voice treatment selection following vocal fold mucosal resection in a Medicare population. Study Design Retrospective analysis of a large, nationally-representative Medicare claims database. Methods Patients with >12 months of continuous Medicare coverage who underwent a leukoplakia- or cancer-related vocal fold mucosal resection (index) procedure during calendar years 2004–2009 were studied. The primary outcome of interest was receipt of initial voice treatment (thyroplasty, vocal fold injection, or speech therapy) following the index procedure. We evaluated the cumulative incidence of each post-index treatment type treating the other treatment types as competing risks, and further evaluated post-index treatment utilization using the proportional hazards model for the subdistribution of a competing risk. Patient age, sex and Medicaid eligibility were used as predictors. Results 2041 patients underwent 2427 index procedures during the study period. An initial voice treatment event was identified in 14% of cases. Women were significantly less likely to receive surgical or behavioral treatment compared to men. From age 65–75 years, the likelihood of undergoing surgical treatment increased significantly with each 5-year age increase; after age 75 years, the likelihood of undergoing either surgical or behavioral treatment decreased significantly every 5 years. Patients with low socioeconomic status were significantly less likely to undergo speech therapy. Conclusions The majority of Medicare patients do not undergo voice treatment following vocal fold mucosal resection. Further, the treatments analyzed here appear disproportionally utilized based on patient sex, age and socioeconomic status. Additional research is needed to determine whether these observations reflect clinically explainable differences or disparities in care. Level of Evidence 2c PMID:26972900

Temporal changes in outcomes of women and men undergoing percutaneous coronary intervention for chronic total occlusion: 2005-2013.

PubMed

Toma, Aurel; Stähli, Barbara E; Gick, Michael; Ferenc, Miroslaw; Mashayekhi, Kambis; Buettner, Heinz Joachim; Neumann, Franz-Josef; Gebhard, Catherine

2018-06-01

Percutaneous coronary intervention (PCI) for chronic total occlusion (CTO) has undergone impressive progress during the last decade, both in strategies and equipment. It is unknown whether technical refinement has translated into improved outcomes in women undergoing CTO-PCI. A total of 2002 consecutive patients (17% females, mean age 65.2 ± 10.7 years) undergoing PCI of at least one CTO lesion at our center between 01/2005 and 12/2013 were evaluated. The incidence of adverse events was compared between two time series (2005-2009 and 2010-2013). A significant increase in adverse lesion characteristics over time was noted in both, women and men (p < 0.001), while technical success rates significantly increased in men but not in women (p trend  < 0.001 in men and p trend =0.9 in women). The incidence of procedural complications was significantly higher in women as compared to men and increased over the study period in women (p < 0.05) but not in men. Accordingly, multivariate logistic regression analysis identified female sex as a strong predictor of PCI-related complications in recent years, while this was not the case in earlier years (adjusted HR 2.03, 95% CI 0.62-6.6, p = 0.2 and adjusted HR 4.7, 95% CI 1.8-12.3, p = 0.002, respectively, p < 0.001 for log LH ratio). In addition, major adverse cardiovascular events (MACE) after a 3-year follow-up significantly declined in men (log rank = 0.046), while no changes were observed in women. While higher success rates and a reduced rate of MACE have been achieved in men, the incidence of procedural complications in women undergoing CTO-PCI has increased over time.

The impact of a 600-mg loading dose of clopidogrel in diabetic and non-diabetic patients undergoing elective PCI.

PubMed

Mohareb, Mina W; Abd Elghany, Mohamed; Sabry, Nirmeen A; Farid, Samar F

2016-08-01

High platelet reactivity (HPR) and suboptimal response to dual antiplatelet therapy (DAPT) may explain high recurrent rates of ischemic events in type 1 and 2 diabetes mellitus (DM) patients undergoing percutaneous coronary intervention (PCI). The aim of this study was to determine the effect of diabetes mellitus on clopidogrel activity in cardiac patients undergoing PCI. This is an observational study. Patients were categorized according to DM status into diabetic group (N.=30) and non-diabetic group (N.=33). All patients received clopidogrel in a loading dose of 600 mg before PCI. Platelet function was assessed using light transmittance aggregometry (LTA) technique at baseline (before clopidogrel administration), 24 hour after clopidogrel loading dose administration and 7-10 days after PCI. All patients were followed up for at least one year after PCI for recurrence of acute cardiac events. There was no statistically significant difference between the two groups with respect to 10 µm adenosine diphosphate (ADP)-induced platelet aggregation measured at baseline (P=0.64), 24 hours after PCI (P=0.874), and 7-10 days after PCI (0.643). Diabetics were not significantly different from non-diabetics in terms of post-PCI acute stent thrombosis (P=0.945), sub-acute stent thrombosis (P=0.945), unstable angina (P=0.29) and cardiac death (P=0.64). There was a statistically significant difference between patients with and without post-PCI acute events regarding ADP aggregation measured 24 hours and 7-10 days after PCI. The use of a high loading dose of clopidogrel (600 mg) in patients undergoing elective PCI can overcome the significant increase in post-PCI platelet aggregation and rate of acute cardiac events induced by diabetes mellitus as co-morbidity in those patients.

Variation of the radiative properties during black carbon aging: theoretical and experimental intercomparison

DOE PAGES

He, C.; Liou, K.-N.; Takano, Y.; ...

2015-10-28

A theoretical black carbon (BC) aging model is developed to account for three typical evolution stages, namely, freshly emitted aggregates, BC coated by soluble material, and BC particles undergoing further hygroscopic growth. The geometric-optics surface-wave (GOS) approach is employed to compute the BC single-scattering properties at each aging stage, which are subsequently compared with laboratory measurements. Theoretical calculations are consistent with measurements in extinction and absorption cross sections for fresh BC aggregates with different BC sizes (i.e., mobility diameters of 155, 245, and 320 nm), with differences of ≤ 25 %. The measured optical cross sections for BC coated bymore » sulfuric acid and for that undergoing further hygroscopic growth are generally captured (differences < 30 %) by theoretical calculations using a concentric core-shell structure, with an overestimate in extinction and absorption of the smallest BC size and an underestimate in scattering of the largest BC size. We find that the absorption and scattering cross sections of fresh BC aggregates vary by 20–40 and 50–65 %, respectively, due to the use of upper (1.95–0.79 i) and lower (1.75–0.63 i) bounds of BC refractive index, while the variations are < 20 % in absorption and < 50 % in scattering in the case of coated BC particles. Sensitivity analyses of the BC morphology show that the optical properties of fresh BC aggregates are more sensitive to fractal dimension than primary spherule size. The absorption and scattering cross sections of coated BC particles vary by more than a factor of 2 due to different coating structures. We find an increase of 20–250 % in absorption and a factor of 3–15 in scattering during aging, significantly depending on coating morphology and aging stages. This study suggests that an accurate estimate of BC radiative effects requires the incorporation of a dynamic BC aging process that accounts for realistic coating structures in climate models.« less

Synthesis, structure and reactivity of a terminal magnesium fluoride compound, [TpBut,Me]MgF: hydrogen bonding, halogen bonding and C-F bond formation.

PubMed

Rauch, Michael; Ruccolo, Serge; Mester, John Paul; Rong, Yi; Parkin, Gerard

2016-01-01

The bulky tris(3- tert -butyl-5-pyrazolyl)hydroborato ligand, [Tp Bu t ,Me ], has been employed to obtain the first structurally characterized example of a molecular magnesium compound that features a terminal fluoride ligand, namely [Tp Bu t ,Me ]MgF, via the reaction of [Tp Bu t ,Me ]MgMe with Me 3 SnF. The chloride, bromide and iodide complexes, [Tp Bu t ,Me ]MgX (X = Cl, Br, I), can also be obtained by an analogous method using Me 3 SnX. The molecular structures of the complete series of halide derivatives, [Tp Bu t ,Me ]MgX (X = F, Cl, Br, I) have been determined by X-ray diffraction. In each case, the Mg-X bond lengths are shorter than the sum of the covalent radii, thereby indicating that there is a significant ionic component to the bonding, in agreement with density functional theory calculations. The fluoride ligand of [Tp Bu t ,Me ]MgF undergoes halide exchange with Me 3 SiX (X = Cl, Br, I) to afford [Tp Bu t ,Me ]MgX and Me 3 SiF. The other halide derivatives [Tp Bu t ,Me ]MgX undergo similar exchange reactions, but the thermodynamic driving forces are much smaller than those involving fluoride transfer, a manifestation of the often discussed silaphilicity of fluorine. In accord with the highly polarized Mg-F bond, the fluoride ligand of [Tp Bu t ,Me ]MgF is capable of serving as a hydrogen bond and halogen bond acceptor, such that it forms adducts with indole and C 6 F 5 I. [Tp Bu t ,Me ]MgF also reacts with Ph 3 CCl to afford Ph 3 CF, thereby demonstrating that [Tp Bu t ,Me ]MgF may be used to form C-F bonds.

Variation of the radiative properties during black carbon aging: theoretical and experimental intercomparison

DOE Office of Scientific and Technical Information (OSTI.GOV)

He, C.; Liou, K.-N.; Takano, Y.

A theoretical black carbon (BC) aging model is developed to account for three typical evolution stages, namely, freshly emitted aggregates, BC coated by soluble material, and BC particles undergoing further hygroscopic growth. The geometric-optics surface-wave (GOS) approach is employed to compute the BC single-scattering properties at each aging stage, which are subsequently compared with laboratory measurements. Theoretical calculations are consistent with measurements in extinction and absorption cross sections for fresh BC aggregates with different BC sizes (i.e., mobility diameters of 155, 245, and 320 nm), with differences of ≤ 25 %. The measured optical cross sections for BC coated bymore » sulfuric acid and for that undergoing further hygroscopic growth are generally captured (differences < 30 %) by theoretical calculations using a concentric core-shell structure, with an overestimate in extinction and absorption of the smallest BC size and an underestimate in scattering of the largest BC size. We find that the absorption and scattering cross sections of fresh BC aggregates vary by 20–40 and 50–65 %, respectively, due to the use of upper (1.95–0.79 i) and lower (1.75–0.63 i) bounds of BC refractive index, while the variations are < 20 % in absorption and < 50 % in scattering in the case of coated BC particles. Sensitivity analyses of the BC morphology show that the optical properties of fresh BC aggregates are more sensitive to fractal dimension than primary spherule size. The absorption and scattering cross sections of coated BC particles vary by more than a factor of 2 due to different coating structures. We find an increase of 20–250 % in absorption and a factor of 3–15 in scattering during aging, significantly depending on coating morphology and aging stages. This study suggests that an accurate estimate of BC radiative effects requires the incorporation of a dynamic BC aging process that accounts for realistic coating structures in climate models.« less

Structural, Nursing, and Physician Characteristics and 30-Day Mortality for Patients Undergoing Cardiac Surgery in Pennsylvania.

PubMed

Lane-Fall, Meghan B; Ramaswamy, Tara S; Brown, Sydney E S; He, Xu; Gutsche, Jacob T; Fleisher, Lee A; Neuman, Mark D

2017-09-01

Cardiac surgery ICU characteristics and clinician staffing patterns have not been well characterized. We sought to describe Pennsylvania cardiac ICUs and to determine whether ICU characteristics are associated with mortality in the 30 days after cardiac surgery. From 2012 to 2013, we conducted a survey of cardiac surgery ICUs in Pennsylvania to assess ICU structure, care practices, and clinician staffing patterns. ICU data were linked to an administrative database of cardiac surgery patient discharges. We used logistic regression to measure the association between ICU variables and death in 30 days. Cardiac surgery ICUs in Pennsylvania. Patients having coronary artery bypass grafting and/or cardiac valve repair or replacement from 2009 to 2011. None. Of the 57 cardiac surgical ICUs in Pennsylvania, 43 (75.4%) responded to the facility survey. Rounds included respiratory therapists in 26 of 43 (60.5%) and pharmacists in 23 of 43 (53.5%). Eleven of 41 (26.8%) reported that at least 2/3 of their nurses had a bachelor's degree in nursing. Advanced practice providers were present in most of the ICUs (37/43; 86.0%) but residents (8/42; 18.6%) and fellows (7/43; 16.3%) were not. Daytime intensivists were present in 21 of 43 (48.8%) responding ICUs; eight of 43 (18.6%) had nighttime intensivists. Among 29,449 patients, there was no relationship between mortality and nurse ICU experience, presence of any intensivist, or absence of residents after risk adjustment. To exclude patients who may have undergone transcatheter aortic valve replacement, we conducted a subgroup analysis of patients undergoing only coronary artery bypass grafting, and results were similar. Pennsylvania cardiac surgery ICUs have variable structures, care practices, and clinician staffing, although none of these are statistically significantly associated with mortality in the 30 days following surgery after adjustment.

Scoping review of the literature on shoulder impairments and disability after neck dissection.

PubMed

Goldstein, David P; Ringash, Jolie; Bissada, Eric; Jaquet, Yves; Irish, Jonathan; Chepeha, Douglas; Davis, Aileen M

2014-02-01

The purpose of this article was to provide a review of the literature on shoulder disability after neck dissection. A literature review was performed using Ovid Medline and Embase databases. A total of 306 abstracts and 78 full-text articles were reviewed. Forty-two articles were eligible for inclusion. Patients undergoing nerve-sacrifice neck dissections have greater disability and lower quality of life scores than those undergoing neck dissections with the least manipulation (ie, selective neck dissections). Shoulder impairments can still occur in patients undergoing selective neck dissections. Disability typically improves over time in patients undergoing nerve-sparing neck dissections. There was significant variability in the literature in terms of the prevalence and recovery of shoulder morbidity after neck dissection. This variability may not just be related to surgical technique or rehabilitation, but also to study design, definitions, and the variability in disability questionnaires used. Copyright © 2013 Wiley Periodicals, Inc.

Cognitive function and adherence of older adults undergoing hemodialysis.

PubMed

Hain, Debra J

2008-01-01

As the number of older adults undergoing hemodialysis increases, it is important for nurses to consider cognitive impairment as a contributing factor to non-adherence. The purpose of this exploratory study was to identify cognitive markers that nurses can use to alert them to potential problems with adherence among older adults undergoing hemodialysis. Stories of the health challenge of making lifestyle change were analyzed with a linguistic analysis software program. A standardized instrument (3MS) that measures global cognitive function was administered. Determination of adherence level was the last activity of data collection. In this sample (n=63), 39.7% of the participants had evidence of cognitive impairment (3MS score less than 80); 58.2% of the 39.7% had evidence of non-adherence. There was a significant relationship between word use and cognitive function (p < .01). Cognitive impairment is prevalent among older adults undergoing hemodialysis and words might be a proxy for recognizing this.

Female Partner Acceptance as a Predictor of Men's Readiness to Undergo Voluntary Medical Male Circumcision in Zambia: The Spear and Shield Project.

PubMed

Cook, Ryan; Jones, Deborah; Redding, Colleen A; Zulu, Robert; Chitalu, Ndashi; Weiss, Stephen M

2016-11-01

The World Health Organization has recommended the scale-up of voluntary medical male circumcision (VMMC) for HIV prevention in sub-Saharan Africa; however, men are often uninterested in undergoing VMMC. The Spear & Shield project enrolled 668 men and female partners from ten Zambian community health centers into parallel interventions promoting VMMC for HIV prevention or time-matched control conditions. A mediation model was utilized to examine the relationships between changes in women's acceptance of VMMC and men's readiness to undergo the procedure. Results demonstrated that, at 12 months post-intervention, a 5.9 % increase in the likelihood of undergoing VMMC among men in the experimental condition could be attributed to increased women's acceptance. From a public health perspective, involving women in VMMC promotion interventions such as the Spear & Shield project could significantly impact the demand for VMMC in Zambia.

Structure of a randomly grown 2-d network.

PubMed

Ajazi, Fioralba; Napolitano, George M; Turova, Tatyana; Zaurbek, Izbassar

2015-10-01

We introduce a growing random network on a plane as a model of a growing neuronal network. The properties of the structure of the induced graph are derived. We compare our results with available data. In particular, it is shown that depending on the parameters of the model the system undergoes in time different phases of the structure. We conclude with a possible explanation of some empirical data on the connections between neurons. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Electromagnetic Characterization Of Metallic Sensory Alloy

NASA Technical Reports Server (NTRS)

Wincheski, Russell A.; Simpson, John; Wallace, Terryl A.; Newman, John A.; Leser, Paul; Lahue, Rob

2012-01-01

Ferromagnetic shape-memory alloy (FSMA) particles undergo changes in both electromagnetic properties and crystallographic structure when strained. When embedded in a structural material, these attributes can provide sensory output of the strain state of the structure. In this work, a detailed characterization of the electromagnetic properties of a FSMA under development for sensory applications is performed. In addition, a new eddy current probe is used to interrogate the electromagnetic properties of individual FSMA particles embedded in the sensory alloy during controlled fatigue tests on the multifunctional material.

Electromagnetic characterization of metallic sensory alloy

NASA Astrophysics Data System (ADS)

Wincheski, Buzz; Simpson, John; Wallace, Terryl; Newman, Andy; Leser, Paul; Lahue, Rob

2013-01-01

Ferromagnetic shape-memory alloy (FSMA) particles undergo changes in both electromagnetic properties and crystallographic structure when strained. When embedded in a structural material, these attributes can provide sensory output of the strain state of the structure. In this work, a detailed characterization of the electromagnetic properties of a FSMA under development for sensory applications is performed. In addition, a new eddy current probe is used to interrogate the electromagnetic properties of individual FSMA particles embedded in the sensory alloy during controlled fatigue tests on the multifunctional material.

A comparison study of immune-inflammatory response in electroacupuncture and transcutaneous electrical nerve stimulation for patients undergoing supratentorial craniotomy

PubMed Central

Li, Guoyan; Li, Shuqin; Sun, Lizhi; Lin, Fangcai; Wang, Baoguo

2015-01-01

Objective: The effect of transcutaneous electrical nerve stimulation (TENS) on immuno-inflammatory response was tested and the differences between electroacupuncture (EA) and TENS in immuno-inflammatory response in patients undergoing supratentorial craniotomy were explored. Methods: 51 patients received craniotomy were randomly divided into 3 groups: control (group C, n=18), EA (group A, n=19) and TENS (group T, n=14) groups. Blood samples were collected before anesthesia (T0) and 30 min (T1), 2 h (T2) and 4 h (T3) after induction of anesthesia to measure the levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-8, IL-10, IgM, IgA and IgG. Results: No significant difference existed between group A and group T during craniotomy. IgM and IgA decreased significantly in group C compared with groups A and T at T2 and T3 time points. Compared with group C, there were significant differences in TNF-α, IgM and IgA levels at T0 in groups A and T; no significant difference was found in the levels of IgG, IL-10 and IL-8. Conclusion: EA and TENS could reduce immunosuppression in patients undergoing supratentorial craniotomy and it has significance in choice of treatment in immunosuppressive therapy. PMID:25785107

A comparison study of immune-inflammatory response in electroacupuncture and transcutaneous electrical nerve stimulation for patients undergoing supratentorial craniotomy

PubMed Central

Li, Guoyan; Li, Shuqin; Sun, Lizhi; Lin, Fangcai; Wang, Baoguo

2015-01-01

Objective: The effect of transcutaneous electrical nerve stimulation (TENS) on immuno-inflammatory response was tested and the differences between electroacupuncture (EA) and TENS in immuno-inflammatory response in patients undergoing supratentorial craniotomy were explored. Methods: 51 patients received craniotomy were divided randomly into 3 groups: control (group C, n=18), EA (group A, n=19) and TENS (group T, n=14) groups. Blood samples were collected before anesthesia (T0) and 30 min (T1), 2 h (T2) and 4 h (T3) after induction of anesthesia to measure the levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-8, IL-10, IgM, IgA and IgG.. Results: No significant difference existed between groups A and group T during craniotomy. IgM and IgA decreased significantly in group C compared with groups A and T at T2 and T3 time points. Compared with group C, there were significant difference in TNF-α, IgM and IgA level at T0 in groups A and T; no significant difference was found in the levels of IgG, IL-10 and IL-8. Conclusion: EA and TENS could reduce immunosuppression in patients undergoing supratentorial craniotomy and it has significance in choice of treatment in immunosuppressive therapy. PMID:25932216

Recycling of cobalt from spent Li-ion batteries as β-Co(OH)2 and the application of Co3O4 as a pseudocapacitor

NASA Astrophysics Data System (ADS)

Barbieri, E. M. S.; Lima, E. P. C.; Lelis, M. F. F.; Freitas, M. B. J. G.

2014-12-01

This work has investigated recycling cobalt from the cathodes of spent Li-ion batteries as β-Co(OH)2, obtaining Co3O4. β-Co(OH)2 with a hexagonal structure by using chemical precipitation (CP) or electrochemical precipitation (EP). In addition, the study has investigated whether the charge density applied directly affects the β-Co(OH)2 morphology. Co3O4 is formed by heat-treating β-Co(OH)2 at 450 °C for 3 h (h) in an air atmosphere. After calcining, the Co3O4 shows a cubic structure and satisfactory purity grade, regardless of the route used for preparation via which it was obtained. Cyclic voltammetry (CV) is then used for electrochemical characterization of the Co3O4 composite electrodes. In the cathodic process, CoO2 undergoes reduction to CoOOH, which undergoes further reduction to Co3O4. In the anodic process, Co3O4 undergoes oxidation to CoOOH, which simultaneously undergoes further oxidation to CoO2. The composite electrodes containing Co3O4, carbon black, and epoxy resin show great reversibility, charge efficiency, and a specific capacitance of 13.0 F g-1 (1.0 mV s-1). The synthesis method of Co(OH)2 influences the charge efficiency of Co3O4 composite electrodes at a scan rate of 10.0 mV s-1. Therefore, in addition to presenting an alternative use for exhausted batteries, Co3O4 composites exhibit favorable characteristics for use as pseudocapacitors.

Mixed valence and metamagnetism in a metal flux grown compound Eu{sub 2}Pt{sub 3}Si{sub 5}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sarkar, Sumanta; Subbarao, Udumula; Joseph, Boby

A new compound Eu{sub 2}Pt{sub 3}Si{sub 5} with plate shaped morphology has been grown from excess In flux. The compound crystallizes in the orthorhombic U{sub 2}Co{sub 3}Si{sub 5} structure type, Ibam space group and the lattice parameters are a=10.007(2) Å, b=11.666(2) Å and c=6.0011(12) Å. The crystal structure of this compound can be conceived as inter-twinned chains of [Pt{sub 2}Si{sub 2}] and [PtSi{sub 3}] tetrahedra connected along [100] direction to give rise to a complex three dimensional [Pt{sub 3}Si{sub 5}] network. Temperature dependent magnetic susceptibility data suggests that Eu{sub 2}Pt{sub 3}Si{sub 5} undergoes a strong antiferromagnetic ordering (T{sub N}=19 K)more » followed by a weak ferromagnetic transition (T{sub C}=5.5 K). The effective magnetic moment/Eu obtained from susceptibility data is 6.78 μ{sub B} accounts mixed valent Eu with almost 85% divalent Eu, which is supported by X-ray absorption near edge spectroscopy. The compound undergoes a metamagnetic transition under applied magnetic field through a probable spin flop mechanism. - Graphical abstract: Eu{sub 2}Pt{sub 3}Si{sub 5}, a new member in the U{sub 2}Co{sub 3}Si{sub 5} (Ibam) family undergoes metamagnetic transition at high magnetic field and Eu is in mixed valence state. - Highlights: • A new compound Eu{sub 2}Pt{sub 3}Si{sub 5} has been synthesized using indium as an inactive metal flux. • The compound undergoes metamagnetic transition at higher field. • Eu in this compound resides in a mixed valence state.« less

Detection of BK virus and adenovirus in the urine from children after allogeneic stem cell transplantation.

PubMed

Hatakeyama, Naoki; Suzuki, Nobuhiro; Yamamoto, Masaki; Kuroiwa, Yuki; Hori, Tsukasa; Mizue, Nobuo; Tsutsumi, Hiroyuki

2006-01-01

The development of hemorrhagic cystitis (HC) and urinary excretion of polyoma BK virus (BKV) and adenovirus (ADV) was investigated by polymerase chain reaction in 20 children undergoing allogeneic stem cell transplantation. Five children developed HC, and all of them excreted BKV; however, only 1 excreted ADV, suggesting that BKV is more significant cause of HC than ADV in children undergoing stem cell transplantation.

The Role of Palliative Surgery in Gynecologic Cancer Cases

PubMed Central

Hope, Joanie Mayer

2013-01-01

The decision to undergo major palliative surgery in end-stage gynecologic cancer is made when severe disease symptoms significantly hinder quality of life. Malignant bowel obstruction, unremitting pelvic pain, fistula formation, tumor necrosis, pelvic sepsis, and chronic hemorrhage are among the reasons patients undergo palliative surgeries. This review discusses and summarizes the literature on surgical management of malignant bowel obstruction and palliative pelvic exenteration in gynecologic oncology. PMID:23299775

Acute normovolemic hemodilution is safe in neurosurgery.

PubMed

Oppitz, Paulo P; Stefani, Marco A

2013-01-01

To determine the safety of acute normovolemic hemodilution (ANH) for patients undergoing neurosurgical procedures. A group of 100 patients undergoing neurosurgical procedures was assigned prospectively to receive ANH. A group of 47 patients who underwent craniotomy for aneurysm clipping and standard anesthetic management was used as a control. Procedures conducted under ANH were performed without significant variations in physiologic parameters. Compared with controls, intraoperative blood loss, operative time, incidence and grade of complications, and length of hospital stay were similar between the two groups. Although the ANH group showed a difference in prothrombin levels before and after hemodilution procedures, the levels were still considered within physiologic parameters. Platelet counts and partial thromboplastin time (PTT) levels indicated no significant variations in either group. During the ANH procedure, a considerable reduction of brain oxygen extraction was observed in individuals with worse preoperative neurologic status (P < 0.05), indicating potential benefit. Among patients with cerebral aneurysm, patients with good initial clinical grades had better clinical results as indicated by Glasgow Outcome Scale scores (P < 0.02). ANH is a safe procedure for patients undergoing neurosurgical procedures. Further studies are necessary to confirm the improvement in brain oxygen extraction and the clinical impact. Nonetheless, patients undergoing aneurysm clipping with good clinical grades seem to profit from ANH. Copyright © 2013 Elsevier Inc. All rights reserved.

Feasible and promising modified trans-subxiphoid thoracoscopic extended thymectomy for patients with myasthenia gravis.

PubMed

Shiomi, Kazu; Kitamura, Eiji; Ono, Mototsugu; Kondo, Yasuto; Naito, Masahito; Mikubo, Masashi; Matsui, Yoshio; Nishiyama, Kazutoshi; Suda, Takashi; Satoh, Yukitoshi

2018-03-01

We have used a promising, minimally invasive thoracoscopic technique of extended thymectomy for patients with myasthenia gravis (MG). The aim of this study was to report our promising technique, a modified single-port trans-subxiphoid approach (MTXA) and to compare perioperative outcomes and effects on MG between our approach and sternotomy. We retrospectively reviewed records of all patients undergoing extended thymectomy for MG and/or thymoma between January 1, 2010 and December 31, 2016. The patients were divided into the MTXA group and Sternotomy group. Of the 50 consecutive patients undergoing extended thymectomy for MG, finally, 13 patients undergoing our MTXA extended thymectomy technique were compared with 20 patients undergoing extended thymectomy via sternotomy. Intraoperative blood loss, postoperative length of stay, and C-reactive protein value on postoperative day 1 were significantly more favorable in the MTXA group than the Sternotomy group (P<0.0001, P=0.0040 and P=0.0073, respectively). Furthermore, no significant differences in the frequency of patients with improvement of their Quantitative Myasthenia Gravis score and/or MG-Activities of Daily Living scale, decrease in the serum level of acetylcholine receptor antibody, and dose reduction of oral prednisone were seen between the two groups. Our approach to extended thymectomy might be more favorable than sternotomy in patients with MG.

Left atrial concomitant surgical ablation for treatment of atrial fibrillation in cardiac surgery: A meta-analysis of randomized controlled trials

PubMed Central

Wang, Chunguo; Ye, Minhua; Lin, Jiang; Jin, Jiang; Hu, Quanteng; Zhu, Chengchu; Chen, Baofu

2018-01-01

Introduction Surgical ablation is a generally established treatment for patients with atrial fibrillation undergoing concomitant cardiac surgery. Left atrial (LA) lesion set for ablation is a simplified procedure suggested to reduce the surgery time and morbidity after procedure. The present meta-analysis aims to explore the outcomes of left atrial lesion set versus no ablative treatment in patients with AF undergoing cardiac surgery. Methods A literature research was performed in six database from their inception to July 2017, identifying all relevant randomized controlled trials (RCTs) comparing left atrial lesion set versus no ablative treatment in AF patient undergoing cardiac surgery. Data were extracted and analyzed according to predefined clinical endpoints. Results Eleven relevant RCTs were included for analysis in the present study. The prevalence of sinus rhythm in ablation group was significantly higher at discharge, 6-month and 1-year follow-up period. The morbidity including 30 day mortality, late all-cause mortality, reoperation for bleeding, permanent pacemaker implantation and neurological events were of no significant difference between two groups. Conclusions The result of our meta-analysis demonstrates that left atrial lesion set is an effective and safe surgical ablation strategy for AF patients undergoing concomitant cardiac surgery. PMID:29360851

Return to Sport and Performance After Microfracture in the Knees of National Basketball Association Players

PubMed Central

Harris, Joshua D.; Walton, David M.; Erickson, Brandon J.; Verma, Nikhil N.; Abrams, Geoffrey D.; Bush-Joseph, Charles A.; Bach, Bernard R.; Cole, Brian J.

2013-01-01

Background: Use of microfracture in the knees of National Basketball Association (NBA) players is controversial. Hypotheses: (1) There would be a high rate of return to sport (RTS) in NBA players following microfracture, (2) players would RTS the season following surgery, (3) preoperative player performance would not be significantly different on RTS, and (4) there would be no significant difference in RTS rate or postoperative performance in players undergoing microfracture in comparison with an age-, position-, NBA experience–, and performance-matched control group. Study Design: Cohort study; Level of evidence, 3. Methods: NBA players undergoing microfracture were evaluated. Age-, body mass index–, position-, NBA experience–, and performance-matched controls were selected from the NBA during the same years as those undergoing microfracture. An index year was selected (controls) to match the number of seasons of NBA experience in microfracture cases. RTS and performance were analyzed and compared between cases and controls. Student t tests were performed for analysis of within- and between-group variables. Results: A total of 41 NBA players underwent microfracture and were compared with 41 demographic- and performance-matched controls. Rate of RTS after microfracture was 73% in the NBA and 83% in professional basketball (NBA, D-league, and International Basketball Federation [FIBA]). Time to RTS in NBA was 9.20 ± 4.88 months. Seventy-one percent (29/41) of players RTS the season following microfracture. Length of NBA career following microfracture (4.10 ± 3.91 years) was not significantly different from controls. After microfracture, case athletes played fewer games per season and with fewer points and steals per game (relative to premicrofracture; P < .05). Performance was better in control (after index year) versus case players (after microfracture) with regard to points per game, games played per season, and field goal and free throw percentage (P < .05). Conclusion: Eighty-three percent of NBA players undergoing microfracture returned to professional basketball. Career length was not significantly different between players undergoing microfracture and controls. However, following microfracture, players competed in fewer games per season with fewer points and steals. PMID:26535256

Return to Sport and Performance After Microfracture in the Knees of National Basketball Association Players.

PubMed

Harris, Joshua D; Walton, David M; Erickson, Brandon J; Verma, Nikhil N; Abrams, Geoffrey D; Bush-Joseph, Charles A; Bach, Bernard R; Cole, Brian J

2013-11-01

Use of microfracture in the knees of National Basketball Association (NBA) players is controversial. (1) There would be a high rate of return to sport (RTS) in NBA players following microfracture, (2) players would RTS the season following surgery, (3) preoperative player performance would not be significantly different on RTS, and (4) there would be no significant difference in RTS rate or postoperative performance in players undergoing microfracture in comparison with an age-, position-, NBA experience-, and performance-matched control group. Cohort study; Level of evidence, 3. NBA players undergoing microfracture were evaluated. Age-, body mass index-, position-, NBA experience-, and performance-matched controls were selected from the NBA during the same years as those undergoing microfracture. An index year was selected (controls) to match the number of seasons of NBA experience in microfracture cases. RTS and performance were analyzed and compared between cases and controls. Student t tests were performed for analysis of within- and between-group variables. A total of 41 NBA players underwent microfracture and were compared with 41 demographic- and performance-matched controls. Rate of RTS after microfracture was 73% in the NBA and 83% in professional basketball (NBA, D-league, and International Basketball Federation [FIBA]). Time to RTS in NBA was 9.20 ± 4.88 months. Seventy-one percent (29/41) of players RTS the season following microfracture. Length of NBA career following microfracture (4.10 ± 3.91 years) was not significantly different from controls. After microfracture, case athletes played fewer games per season and with fewer points and steals per game (relative to premicrofracture; P < .05). Performance was better in control (after index year) versus case players (after microfracture) with regard to points per game, games played per season, and field goal and free throw percentage (P < .05). Eighty-three percent of NBA players undergoing microfracture returned to professional basketball. Career length was not significantly different between players undergoing microfracture and controls. However, following microfracture, players competed in fewer games per season with fewer points and steals.

Relationship of Postprandial Nonesterified Fatty Acids, Adipokines, and Insulin Across Gender in Human Immunodeficiency Virus–Positive Patients Undergoing Highly Active Antiretroviral Therapy

PubMed Central

Lu, Guijing; Thomas-Geevarghese, Asha; Anuurad, Erdembileg; Raghavan, Subhashree; Minolfo, Robert; Ormsby, Bernard; Karmally, Wahida; El-Sadr, Wafaa M.; Albu, Jeanine

2009-01-01

Abstract Background Metabolic derangements are common in human immunodeficiency virus (HIV)-positive subjects undergoing antiretroviral therapy, but little is known about postprandial conditions. Methods We investigated the relationship between leptin, adiponectin, nonesterified fatty acids (NEFA), and insulin in response to a day-long meal pattern and evaluated gender differences in HIV-positive men (n = 12) and women (n = 13) undergoing highly active antiretroviral therapy (HAART). Results For both men and women, a significant decrease in postprandial NEFA levels was observed following breakfast (0.53 vs. 0.22 mmol/L, P < 0.001, baseline and at 3 hours, respectively), whereas day-long postprandial leptin and adiponectin levels showed small nonsignificant oscillations. In contrast to NEFA and adiponectin, postprandial leptin levels were significantly higher among women compared to men (P < 0.05). Postprandial NEFA levels correlated positively with fasting insulin levels (r2 = 0.25, P = 0.016), and the postbreakfast decrease in NEFA levels correlated significantly with the postbreakfast increase in insulin levels (r2 = 0.17, P = 0.038). No significant association between postprandial adipokines and insulin was observed. Conclusions In HAART-treated, HIV-infected men and women, levels of NEFA, but not adipokines, showed significant postprandial variation. Furthermore, food intake resulted in significant NEFA suppression in proportion to the food-stimulated insulin increase. PMID:19320559

Pre-exposure to drought increases the resistance of tropical forest soil bacterial communities to extended drought

PubMed Central

Bouskill, Nicholas J; Lim, Hsiao Chien; Borglin, Sharon; Salve, Rohit; Wood, Tana E; Silver, Whendee L; Brodie, Eoin L

2013-01-01

Global climate models project a decrease in the magnitude of precipitation in tropical regions. Changes in rainfall patterns have important implications for the moisture content and redox status of tropical soils, yet little is known about how these changes may affect microbial community structure. Specifically, does exposure to prior stress confer increased resistance to subsequent perturbation? Here we reduced the quantity of precipitation throughfall to tropical forest soils in the Luquillo Mountains, Puerto Rico. Treatments included newly established throughfall exclusion plots (de novo excluded), plots undergoing reduction for a second time (pre-excluded) and ambient control plots. Ten months of throughfall exclusion led to a small but statistically significant decline in soil water potential and bacterial populations clearly adapted to increased osmotic stress. Although the water potential decline was small and microbial biomass did not change, phylogenetic diversity in the de novo-excluded plots decreased by ∼40% compared with the control plots, yet pre-excluded plots showed no significant change. On the other hand, the relative abundances of bacterial taxa in both the de novo-excluded and pre-excluded plots changed significantly with throughfall exclusion compared with control plots. Changes in bacterial community structure could be explained by changes in soil pore water chemistry and suggested changes in soil redox. Soluble iron declined in treatment plots and was correlated with decreased soluble phosphorus concentrations, which may have significant implications for microbial productivity in these P-limited systems. PMID:23151641

Non-linear analysis and the design of Pumpkin Balloons: stress, stability and viscoelasticity

NASA Astrophysics Data System (ADS)

Rand, J. L.; Wakefield, D. S.

Tensys have a long-established background in the shape generation and load analysis of architectural stressed membrane structures Founded upon their inTENS finite element analysis suite these activities have broadened to encompass lighter than air structures such as aerostats hybrid air-vehicles and stratospheric balloons Winzen Engineering couple many years of practical balloon design and fabrication experience with both academic and practical knowledge of the characterisation of the non-linear viscoelastic response of the polymeric films typically used for high-altitude scientific balloons Both companies have provided consulting services to the NASA Ultra Long Duration Balloon ULDB Program Early implementations of pumpkin balloons have shown problems of geometric instability characterised by improper deployment and these difficulties have been reproduced numerically using inTENS The solution lies in both the shapes of the membrane lobes and also the need to generate a biaxial stress field in order to mobilise in-plane shear stiffness Balloons undergo significant temperature and pressure variations in flight The different thermal characteristics between tendons and film can lead to significant meridional stress Fabrication tolerances can lead to significant local hoop stress concentrations particularly adjacent to the base and apex end fittings The non-linear viscoelastic response of the envelope film acts positively to help dissipate stress concentrations However creep over time may produce lobe geometry variations that may

Efficacy of intravenous fluid warming during goal-directed fluid therapy in patients undergoing laparoscopic colorectal surgery: a randomized controlled trial.

PubMed

Choi, Ji-Won; Kim, Duk-Kyung; Lee, Seung-Won; Park, Jung-Bo; Lee, Gyu-Hong

2016-06-01

To evaluate the clinical efficacy of intravenous (IV) fluid warming in patients undergoing laparoscopic colorectal surgery. Adult patients undergoing laparoscopic colorectal surgery were randomly assigned to receive either IV fluids at room temperature (control group) or warmed IV fluids (warm fluids group). Each patient received a standardized goal-directed fluid regimen based on stroke volume variances. Oesophageal temperature was measured at 15 min intervals for 2 h after induction of anaesthesia. A total of 52 patients were enrolled in the study. The drop in core temperature in the warm fluids group was significantly less than in the control group 2 h after the induction of anaesthesia. This significant difference was seen from 30 min after induction. IV fluid warming was associated with a smaller drop in core temperature than room temperature IV fluids in laparoscopic colorectal surgery incorporating goal-directed fluid therapy. © The Author(s) 2016.

On the evolution of vortices in massive protoplanetary discs

NASA Astrophysics Data System (ADS)

Pierens, Arnaud; Lin, Min-Kai

2018-05-01

It is expected that a pressure bump can be formed at the inner edge of a dead-zone, and where vortices can develop through the Rossby Wave Instability (RWI). It has been suggested that self-gravity can significantly affect the evolution of such vortices. We present the results of 2D hydrodynamical simulations of the evolution of vortices forming at a pressure bump in self-gravitating discs with Toomre parameter in the range 4 - 30. We consider isothermal plus non-isothermal disc models that employ either the classical β prescription or a more realistic treatment for cooling. The main aim is to investigate whether the condensating effect of self-gravity can stabilize vortices in sufficiently massive discs. We confirm that in isothermal disc models with Q ≳ 15, vortex decay occurs due to the vortex self-gravitational torque. For discs with 3≲ Q ≲ 7, the vortex develops gravitational instabilities within its core and undergoes gravitational collapse, whereas more massive discs give rise to the formation of global eccentric modes. In non-isothermal discs with β cooling, the vortex maintains a turbulent core prior to undergoing gravitational collapse for β ≲ 0.1, whereas it decays if β ≥ 1. In models that incorpore both self-gravity and a better treatment for cooling, however, a stable vortex is formed with aspect ratio χ ˜ 3 - 4. Our results indicate that self-gravity significantly impacts the evolution of vortices forming in protoplanetary discs, although the thermodynamical structure of the vortex is equally important for determining its long-term dynamics.

Incidence of deep vein thrombosis in patients undergoing breast reconstruction with autologous tissue transfer.

PubMed

Konoeda, Hisato; Yamaki, Takashi; Hamahata, Atsumori; Ochi, Masakazu; Osada, Atsuyoshi; Hasegawa, Yuki; Kirita, Miho; Sakurai, Hiroyuki

2017-05-01

Background Breast reconstruction is associated with multiple risk factors for venous thromboembolism. However, the incidence of deep vein thrombosis in patients undergoing breast reconstruction is uncertain. Objective The aim of this study was to prospectively evaluate the incidence of deep vein thrombosis in patients undergoing breast reconstruction using autologous tissue transfer and to identify potential risk factors for deep vein thrombosis. Methods Thirty-five patients undergoing breast reconstruction were enrolled. We measured patients' preoperative characteristics including age, body mass index (kg/m 2 ), and risk factors for deep vein thrombosis. The preoperative diameter of each venous segment in the deep veins was measured using duplex ultrasound. All patients received intermittent pneumatic pump and elastic compression stockings for postoperative thromboprophylaxis. Results Among the 35 patients evaluated, 11 (31.4%) were found to have deep vein thrombosis postoperatively, and one patient was found to have pulmonary embolism postoperatively. All instances of deep vein thrombosis developed in the calf and were asymptomatic. Ten of 11 patients underwent free flap transfer, and the remaining one patient received a latissimus dorsi pedicled flap. Deep vein thrombosis incidence did not significantly differ between patients with a free flap or pedicled flap (P = 0.13). Documented risk factors for deep vein thrombosis demonstrated no significant differences between patients with and without deep vein thrombosis. The diameter of the common femoral vein was significantly larger in patients who developed postoperative deep vein thrombosis than in those who did not ( P < 0.05). Conclusions The morbidity of deep vein thrombosis in patients who underwent breast reconstruction using autologous tissue transfer was relatively high. Since only the diameter of the common femoral vein was predictive of developing postoperative deep vein thrombosis, postoperative pharmacological thromboprophylaxis should be considered for all patients undergoing breast reconstruction regardless of operative procedure.

Comparison of patients' reported pain following office hysteroscopy with and without endometrial biopsy: a prospective study.

PubMed

New, Erika P; Sarkar, Papri; Sappenfield, Elisabeth; Mikhail, Emad; Plosker, Shayne; Imudia, Anthony N

2018-05-31

When performing office based gynecologic procedures, one must provide patients with appropriate counseling on anticipated pain prior to the procedure. The goal of this study was to investigate whether there is any difference in patients' pain perception when office hysteroscopy (OH) is performed alone compared with when it is performed with endometrial biopsy (EMB) for various gynecologic indications. A prospective study was performed of patients undergoing office hysteroscopy alone or in combination with endometrial biopsy between October 2015 and February 2017. Procedures were performed using standard gynecologic techniques. Patients described their post procedural pain using the visual analogue scale from 0-10 and data was compared between groups using SPSS version 24. Group 1 had OH alone (n=243) and group 2 had OH combined with EMB (n=80). Patients who underwent both procedures had significantly higher reported median (range) pain scores than those undergoing OH alone [7 (0-10) vs 5 (0-10), p=.004]. The patients in-group 2 were significantly older than those in group 1 (42.6±7.6 vs 36.6±6.5, p<.0001). The patients in group 2 had higher gravidity (2 vs 1, p=.04), were more likely to have a tenaculum used during the procedure (36.3% vs 21.4%, p=.01) and were more likely to be diagnosed with uterine fibroids (73% vs 31%, p<.0001). After controlling for patients age, gravidity, tenaculum use and diagnosis of fibroids using a multivariable regression model, patients undergoing OH with EMB had a 0.51-unit pain score greater than those that had OH alone; however, this difference was not statistically significant [95% CI (-0.32,1.33 p=.23)]. Patients undergoing both OH and EMB appear to report similar pain scores as those undergoing OH alone after controlling for confounding variables. The presence of fibroids was found to contribute to higher reported pain in the patients having OH in combination with EMB.

Effect of Intraoperative Dexamethasone on Pain Scores and Narcotic Consumption in Patients Undergoing Total Knee Arthroplasty.

PubMed

Samona, Jason; Cook, Carrie; Krupa, Kyle; Swatsell, Krystle; Jackson, Andrew; Dukes, Chase; Martin, Sidney

2017-02-01

To examine whether the addition of intravenous dexamethasone during total knee arthroplasty (TKA) would be effective at reducing postoperative pain scores and postoperative opioid consumption. A total of 102 patients undergoing TKA were placed into two groups: 55 subjects received intraoperative dexamethasone 8 mg intravenously (treatment group) and 47 did not receive dexamethasone at any time during the perioperative period. Comparison was made using the 0-10 numeric pain rating scale and the amount of opioids used in each group. Patients who received dexamethasone required significantly less oral opioids compared to the control group. Pain scores at 24 h post-surgery were significantly less for the dexamethasone group compared to the control group. There was no difference between groups in regards to patient-controlled analgesic dose or pain scores in the post-anesthesia care unit, at 12 or 48 h post-surgery. A single dose of dexamethasone given intraoperatively significantly decreased oral narcotic consumption and decreased pain scores 24 h postoperatively. Dexamethasone appears to be a safe modality to use to control pain in patients undergoing TKA. © 2017 Chinese Orthopaedic Association and John Wiley & Sons Australia, Ltd.

Off-pump coronary artery bypass surgery in severe left ventricular dysfunction.

PubMed

Azarfarin, Rasoul; Pourafkari, Leili; Parvizi, Rezayat; Alizadehasl, Azin; Mahmoodian, Roghaiyeh

2010-02-01

Our aim was to examine hospital outcomes of coronary artery bypass surgery in patients with and without left ventricular dysfunction, with regard to the surgical technique (off- or on-pump). Between March 2007 and March 2008, 689 consecutive patients underwent isolated first-time coronary artery bypass; 127 had ejection fractions < or = 30% (group 1) and 562 had ejection fractions >30% (group 2). Data of preoperative risk profiles and hospital outcomes were collected prospectively. Off-pump operations were performed in 49 (38.6%) patients in group 1 and 196 (34.9%) in group 2. The incidences of infectious, neurologic, and cardiac complications postoperatively were significantly higher in group 1. In multivariate analysis, preoperative ejection fraction < or = 30% was found to be an independent risk factor for postoperative complications and hospital mortality. The subgroup of patients undergoing off-pump surgery in both groups had a significantly lower rate of total complications than those undergoing conventional on-pump operations, but no significant difference in mortality was observed between those undergoing off-pump or conventional surgery in either group. Off-pump surgery helped to limit the increased morbidity rate after coronary bypass in patients with ventricular dysfunction.

The Inequity of Bariatric Surgery: Publicly Insured Patients Undergo Lower Rates of Bariatric Surgery with Worse Outcomes.

PubMed

Hennings, Dietric L; Baimas-George, Maria; Al-Quarayshi, Zaid; Moore, Rachel; Kandil, Emad; DuCoin, Christopher G

2018-01-01

Bariatric surgery has been shown to be the most effective method of achieving weight loss and alleviating obesity-related comorbidities. Yet, it is not being used equitably. This study seeks to identify if there is a disparity in payer status of patients undergoing bariatric surgery and what factors are associated with this disparity. We performed a case-control analysis of National Inpatient Sample. We identified adults with body mass index (BMI) greater than or equal to 25 kg/m 2 who underwent bariatric surgery and matched them with overweight inpatient adult controls not undergoing surgery. The sample was analyzed using multivariate logistic regression. We identified 132,342 cases, in which the majority had private insurance (72.8%). Bariatric patients were significantly more likely to be privately insured than any other payer status; Medicare- and Medicaid-covered patients accounted for a low percentage of cases (Medicare 5.1%, OR 0.33, 95% CI 0.29-0.37, p < 0.001; Medicaid 8.7%, OR 0.21, 95% CI 0.18-0.25, p < 0.001). Medicare (OR 1.54, 95% CI 1.33-1.78, p < 0.001) and Medicaid (OR 1.31, 95% CI 1.08-1.60, p = 0.007) patients undergoing bariatric surgery had an increased risk of complications compared to privately insured patients. Publicly insured patients are significantly less likely to undergo bariatric surgery. As a group, these patients experience higher rates of obesity and related complications and thus are most in need of bariatric surgery.

Hip Fractures and the Bundle: A Cost Analysis of Patients Undergoing Hip Arthroplasty for Femoral Neck Fracture vs Degenerative Joint Disease.

PubMed

Grace, Trevor R; Patterson, Joseph T; Tangtiphaiboontana, Jennifer; Krogue, Justin D; Vail, Thomas P; Ward, Derek T

2018-06-01

The purpose of this study is to determine whether episode Target Prices in the Bundled Payment for Care Improvement (BPCI) initiative sufficiently match the complexities and expenses expected for patients undergoing hip arthroplasty for femoral neck fracture (FNF) as compared to hip degenerative joint disease (DJD). Claims data under BPCI Model 2 were collected for patients undergoing hip arthroplasty at a single institution over a 2-year period. Payments from the index hospitalization to 90 days postoperatively were aggregated by Medicare Severity Diagnosis-Related Group (469 or 470), indication (DJD vs FNF), and categorized as index procedure, postacute services, and related hospital readmissions. Actual episode costs and Target Prices were compared in both the FNF and DJD cohorts undergoing hip arthroplasty to gauge the cost discrepancy in each group. A total of 183 patients were analyzed (31 with FNFs, 152 with DJD). In total, the FNF cohort incurred a $415,950 loss under the current episode Target Prices, whereas the DJD cohort incurred a $172,448 gain. Episode Target Prices were significantly higher than actual episode prices for the DJD cohort ($32,573 vs $24,776, P < .001). However, Target Prices were significantly lower than actual episode prices for the FNF cohort ($32,672 vs $49,755, P = .021). Episode Target Prices in the current BPCI model fall dramatically short of the actual expenses incurred by FNF patients undergoing hip arthroplasty. Better risk-adjusting Target Prices for this fragile population should be considered to avoid disincentives and delays in care. Copyright © 2018 Elsevier Inc. All rights reserved.

Software Architecture Evolution

ERIC Educational Resources Information Center

Barnes, Jeffrey M.

2013-01-01

Many software systems eventually undergo changes to their basic architectural structure. Such changes may be prompted by new feature requests, new quality attribute requirements, changing technology, or other reasons. Whatever the causes, architecture evolution is commonplace in real-world software projects. Today's software architects, however,…

University Transformation: New Demands and Coping Strategies

ERIC Educational Resources Information Center

Chidindi, Joseph

2012-01-01

University education system is undergoing transformation requirements particularly in the developing world. The demands require adaptation to the prevailing circumstances hence the need for relevant strategies for universities. Issues such as institutional profiles, organizational structure and work integration, research activities, and funding…

Adsorption-Induced Changes in Ribonuclease A Structure and Enzymatic Activity on Solid Surfaces

PubMed Central

2015-01-01

Ribonuclease A (RNase A) is a small globular enzyme that lyses RNA. The remarkable solution stability of its structure and enzymatic activity has led to its investigation to develop a new class of drugs for cancer chemotherapeutics. However, the successful clinical application of RNase A has been reported to be limited by insufficient stability and loss of enzymatic activity when it was coupled with a biomaterial carrier for drug delivery. The objective of this study was to characterize the structural stability and enzymatic activity of RNase A when it was adsorbed on different surface chemistries (represented by fused silica glass, high-density polyethylene, and poly(methyl-methacrylate)). Changes in protein structure were measured by circular dichroism, amino acid labeling with mass spectrometry, and in vitro assays of its enzymatic activity. Our results indicated that the process of adsorption caused RNase A to undergo a substantial degree of unfolding with significant differences in its adsorbed structure on each material surface. Adsorption caused RNase A to lose about 60% of its native-state enzymatic activity independent of the material on which it was adsorbed. These results indicate that the native-state structure of RNase A is greatly altered when it is adsorbed on a wide range of surface chemistries, especially at the catalytic site. Therefore, drug delivery systems must focus on retaining the native structure of RNase A in order to maintain a high level of enzymatic activity for applications such as antitumor chemotherapy. PMID:25420087

Simulations of the flocculent spiral M33: what drives the spiral structure?

NASA Astrophysics Data System (ADS)

Dobbs, C. L.; Pettitt, A. R.; Corbelli, E.; Pringle, J. E.

2018-05-01

We perform simulations of isolated galaxies in order to investigate the likely origin of the spiral structure in M33. In our models, we find that gravitational instabilities in the stars and gas are able to reproduce the observed spiral pattern and velocity field of M33, as seen in HI, and no interaction is required. We also find that the optimum models have high levels of stellar feedback which create large holes similar to those observed in M33, whilst lower levels of feedback tend to produce a large amount of small scale structure, and undisturbed long filaments of high surface density gas, hardly detected in the M33 disc. The gas component appears to have a significant role in producing the structure, so if there is little feedback, both the gas and stars organise into clear spiral arms, likely due to a lower combined Q (using gas and stars), and the ready ability of cold gas to undergo spiral shocks. By contrast models with higher feedback have weaker spiral structure, especially in the stellar component, compared to grand design galaxies. We did not see a large difference in the behaviour of Qstars with most of these models, however, because Qstars stayed relatively constant unless the disc was more strongly unstable. Our models suggest that although the stars produce some underlying spiral structure, this is relatively weak, and the gas physics has a considerable role in producing the large scale structure of the ISM in flocculent spirals.

Beach erosion and nest site selection by the leatherback sea turtle Dermochelys coriacea (Testudines: Dermochelyidae) and implications for management practices at Playa Gandoca, Costa Rica.

PubMed

Spanier, Matthew J

2010-12-01

Leatherback sea turtles (Dermochelys coriacea) nest on dynamic, erosion-prone beaches. Erosive processes and resulting nest loss have long been presumed to be a hindrance to clutch survival. In order to better understand how leatherbacks cope with unstable nesting beaches, I investigated the role of beach erosion in leatherback nest site selection at Playa Gandoca, Costa Rica. I also examined the potential effect of nest relocation, a conservation strategy in place at Playa Gandoca to prevent nest loss to erosion, on the temperature of incubating clutches. I monitored changes in beach structure as a result of erosion at natural nest sites during the time the nest was laid, as well as in subsequent weeks. To investigate slope as a cue for nest site selection, I measured the slope of the beach where turtles ascended from the sea to nest, as well as the slopes at other random locations on the beach for comparison. I examined temperature differences between natural and relocated nest sites with thermocouples placed in the sand at depths typical of leatherback nests. Nests were distributed non-randomly in a clumped distribution along the length of the beach and laid at locations that were not undergoing erosion. The slope at nest sites was significantly different than at randomly chosen locations on the beach. The sand temperature at nest depths was significantly warmer at natural nest sites than at locations of relocated nests. The findings of this study suggest leatherbacks actively select nest sites that are not undergoing erosive processes, with slope potentially being used as a cue for site selection. The relocation of nests appears to be inadvertently cooling the nest environment. Due to the fact that leatherback clutches undergo temperature-dependent sex determination, the relocation of nests may be producing an unnatural male biasing of hatchlings. The results of this study suggest that the necessity of relocation practices, largely in place to protect nests from erosion, should be reevaluated to ensure the proper conservation of this critically endangered species.

Anticholinergic premedication to prevent bradycardia in combined spinal anesthesia and dexmedetomidine sedation: a randomized, double-blind, placebo-controlled study.

PubMed

Ahn, Eun Jin; Park, Jun Ha; Kim, Hyo Jin; Kim, Kyung Woo; Choi, Hey Ran; Bang, Si Ra

2016-12-01

When dexmedetomidine is used in patients undergoing spinal anesthesia, high incidence of bradycardia in response to parasympathetic activation is reported. Therefore, we aimed to evaluate the effectiveness of atropine premedication for preventing the incidence of bradycardia and the hemodynamic effect on patients undergoing spinal anesthesia with sedation by dexmedetomidine. Randomized, double-blind, placebo-controlled study. Operating room. One hundred fourteen patients (age range, 2-65 years; American Society of Anesthesiology class I-II) participated in this study, willing to be sedated and to undergo spinal anesthesia. The patients were divided into 2 groups: group A and group C. After performing spinal anesthesia, dexmedetomidine was infused at a loading dose of 0.6 μg/kg for 10 minutes, followed by an infusion at 0.25 μg/(kg h). Simultaneously with the loading dose of dexmedetomidine, patients in group A received an intravenous bolus of 0.5 mg atropine, whereas patients in group C received an intravenous normal saline bolus. Data on administration of atropine and ephedrine were collected. Hemodynamic data including heart rate, systolic blood pressure, diastolic blood pressure (DBP), and mean blood pressure (MBP) were also recorded. The incidence of bradycardia requiring atropine treatment was significantly higher in group C than group A (P=.035). However, the incidence of hypotension needing ephedrine treatment showed no significant difference between the 2 groups (P=.7). Systolic blood pressure and heart rate showed no significant differences between the 2 groups (P=.138 and .464, respectively). However, group A showed significant increases in DBP and MBP, and group C did not (P=.014 and .008, respectively). Prophylactic atropine reduces the incidence of bradycardia in patients undergoing spinal anesthesia with dexmedetomidine sedation. However, DBP and MBP showed significant increases in patients when prophylactic atropine was administrated. Therefore, atropine premedication should be administered cautiously. Copyright © 2016 Elsevier Inc. All rights reserved.

Prevalence of Clostridium Difficile Infection in Patients After Radical Cystectomy and Neoadjuvant Chemotherapy.

PubMed

Cotter, Katherine J; Fan, Yunhua; Sieger, Gretchen K; Weight, Christopher J; Konety, Badrinath R

2017-10-27

Clostridium Difficile is the most common cause of nosocomial infectious diarrhea. This study evaluates the prevalence and predictors of Clostridium Difficile infections in patients undergoing radical cystectomy with or without neoadjuvant chemotherapy. Retrospective chart review was performed of all patients undergoing cystectomy and urinary diversion at a single institution from 2011-2017. Infection was documented in all cases with testing for Clostridium Difficile polymerase chain reaction toxin B. Patient and disease related factors were compared for those who received neoadjuvant chemotherapy vs. those who did not in order to identify potential risk factors associated with C. Difficile infections. Chi squared test and logistic regression analysis were used to determine statistical significance. Of 350 patients who underwent cystectomy, 41 (11.7%) developed Clostridium Difficile in the 30 day post-operative period. The prevalence of C. Difficile infection was higher amongst the patients undergoing cystectomy compared to the non-cystectomy admissions at our hospital (11.7 vs. 2.9%). Incidence was not significantly different among those who underwent cystectomy for bladder cancer versus those who underwent the procedure for other reasons. Median time to diagnosis was 6 days (range 3-28 days). The prevalence of C. Diff infections was not significantly different among those who received neoadjuvant chemotherapy vs. those who did not (11% vs. 10.4% p  = 0.72). A significant association between C. Difficile infection was not seen with proton pump inhibitor use ( p  = 0.48), patient BMI ( p  = 0.67), chemotherapeutic regimen ( p  = 0.94), individual surgeon ( p  = 0.54), type of urinary diversion (0.41), or peri-operative antibiotic redosing ( p  = 0.26). Clostridium Difficile infection has a higher prevalence in patients undergoing cystectomy. No significant association between prevalence and exposure to neoadjuvant chemotherapy was seen.

Adiponectin and resistin in acute and chronic graft-vs-host disease patients undergoing allogeneic hematopoietic stem cell transplantation.

PubMed

Robak, Oliver; Kuzmina, Zoya; Winkler, Andreas; Kalhs, Peter; Rabitsch, Werner; Greinix, Hildegard

2016-06-30

To investigate the association of adiponectin and resistin levels in patients undergoing hematopoietic stem cell transplantation (HSCT) with the clinical outcome, including the occurrence of acute and chronic graft-vs-host disease (GVHD), non-relapse mortality, and overall survival. We prospectively collected serum samples from 40 patients undergoing either autologous (n=12; 10 male) or allogeneic (n=28; 11 male) HSCT for up to 12 months post HSCT and determined adiponectin and resistin serum concentrations using enzyme-linked immunosorbent assay. There were no significant differences in adiponectin levels (18.5 vs 9.3 μg/mL, P=0.071) and adiponectin/BMI ratio (0.82 vs 0.39, P=0.068) between patients with acute GVHD grades 2-4 and autologous controls. However, resistin values were significantly lower in patients with acute GVHD grades 2-4 than in autologous controls (4.6 vs 7.3 ng/mL, P=0.030). Adiponectin levels were higher in patients with chronic GVHD (n=17) than in autologous controls (13.5 vs 7.6 μg/mL, P=0.051), but the difference was not significant. Adiponectin/BMI ratio was significantly higher in patients with chronic GVHD than in autologous controls (0.59 vs 0.25, P=0.006). Patients dying from relapse also had significantly lower adiponectin levels (8.2 μg/mL) and adiponectin/BMI ratio (0.3) on admission than surviving allogeneic (15.8 µg/mL, P=0.030 and 0.7, P=0.004) and surviving autologous patients (19.2 μg/mL, P=0.031 and 0.7, P=0.021). Adiponectin and resistin levels were altered in patients with acute and chronic GVHD compared to autologous controls and were associated with overall survival and relapse mortality in patients undergoing allogeneic HSCT.

Adiponectin and resistin in acute and chronic graft-vs-host disease patients undergoing allogeneic hematopoietic stem cell transplantation

PubMed Central

Robak, Oliver; Kuzmina, Zoya; Winkler, Andreas; Kalhs, Peter; Rabitsch, Werner; Greinix, Hildegard

2016-01-01

Aim To investigate the association of adiponectin and resistin levels in patients undergoing hematopoietic stem cell transplantation (HSCT) with the clinical outcome, including the occurrence of acute and chronic graft-vs-host disease (GVHD), non-relapse mortality, and overall survival. Methods We prospectively collected serum samples from 40 patients undergoing either autologous (n = 12; 10 male) or allogeneic (n = 28; 11 male) HSCT for up to 12 months post HSCT and determined adiponectin and resistin serum concentrations using enzyme-linked immunosorbent assay. Results There were no significant differences in adiponectin levels (18.5 vs 9.3 µg/mL, P = 0.071) and adiponectin/BMI ratio (0.82 vs 0.39, P = 0.068) between patients with acute GVHD grades 2-4 and autologous controls. However, resistin values were significantly lower in patients with acute GVHD grades 2-4 than in autologous controls (4.6 vs 7.3 ng/mL, P = 0.030). Adiponectin levels were higher in patients with chronic GVHD (n = 17) than in autologous controls (13.5 vs 7.6 µg/mL, P = 0.051), but the difference was not significant. Adiponectin/BMI ratio was significantly higher in patients with chronic GVHD than in autologous controls (0.59 vs 0.25, P = 0.006). Patients dying from relapse also had significantly lower adiponectin levels (8.2 µg/mL) and adiponectin/BMI ratio (0.3) on admission than surviving allogeneic (15.8 µg/mL, P = 0.030 and 0.7, P = 0.004) and surviving autologous patients (19.2 µg/mL, P = 0.031 and 0.7, P = 0.021). Conclusion Adiponectin and resistin levels were altered in patients with acute and chronic GVHD compared to autologous controls and were associated with overall survival and relapse mortality in patients undergoing allogeneic HSCT. PMID:27374827

Short-term effects of overnight orthokeratology on corneal cell morphology and corneal thickness.

PubMed

Nieto-Bona, Amelia; González-Mesa, Ana; Nieto-Bona, Ma Paz; Villa-Collar, César; Lorente-Velázquez, Amalia

2011-06-01

To examine the morphological and biometric corneal changes produced over periods of 15 days and 1 month after overnight orthokeratology (OK). Prospective, single-center, longitudinal trial. Twenty-seven right eyes of 27 subjects (group 1) with low to moderate myopia wore OK lenses for 1 month. Ten right eyes of 10 subjects (group 2) with emmetropia to low myopia who did not wear any type of contact lens served as controls. Corneal morphometric measurements were obtained in vivo using a confocal microscope to examine the central and midperipheral cornea. Thickness measurements in the peripheral cornea were obtained by optical coherence tomography. Changes in visual acuity, refractive error, and corneal topography were also analyzed. No significant changes in either endothelial cell or stromal cell density were observed after 1 month of OK. Basal epithelial cells were, however, significantly reduced (P < 0.01), and epithelial wing and superficial cells showed enhanced visibility (P < 0.05). Superficial cells increased in height and width, the width increase after 1 month being significant (P < 0.01). Epithelial thickness was significantly reduced in the central cornea and 2 mm around the center. Corneal pachymetry increased significantly in the band from 5 to 10 mm from the corneal apex (P < 0.01). OK lenses for myopia induce significant structural and optical changes particularly in the central epithelium after 15 days or 1 month of wear. The central corneal epithelium responds to OK wear by undergoing significant epithelial cell shape and size alterations with no effects, however, on the cells of the corneal endothelium or the corneal stroma. Peripheral corneal thickness increased with respect to baseline values. These findings suggest that the corneal epithelium is the principal structure affected by the mechanical forces exerted by the OK lenses.

Analysis/test correlation using VAWT-SDS on a step-relaxation test for the rotating Sandia 34 m test bed

DOE Office of Scientific and Technical Information (OSTI.GOV)

Argueello, J.G.; Dohrmann, C.R.; Carne, T.G.

The combined analysis/test effort described in this paper compares predictions with measured data from a step-relaxation test in the absence of significant wind-driven aerodynamic loading. The process described here is intended to illustrate a method for validation of time domain codes for structural analysis of wind turbine structures. Preliminary analyses were performed to investigate the transient dynamic response that the rotating Sandia 34 m Vertical Axis Wind Turbine (VAWT) would undergo when one of the two blades was excited by step-relaxation. The calculations served two purposes. The first was for pretest planning to evaluate the relative importance of the variousmore » forces that would be acting on the structure during the test and to determine if the applied force in the step-relaxation would be sufficient to produce an excitation that was distinguishable from that produced by the aerodynamic loads. The second was to provide predictions that could subsequently be compared to the data from the test. The test was carried out specifically to help in the validation of the time-domain structural dynamics code, VAWT-SDS, which predicts the dynamic response of VAWTs subject to transient events. Post-test comparisons with the data were performed and showed a qualitative agreement between pretest predictions and measured response. However, they also showed that there was significantly more damping in the measurements than included in the predictions. Efforts to resolve this difference, including post-test analyses, were undertaken and are reported herein. The overall effort described in this paper represents a major step in the process of arriving at a validated structural dynamics code.« less

Structural dynamics and activity of nanocatalysts inside fuel cells by in operando atomic pair distribution studies.

PubMed

Petkov, Valeri; Prasai, Binay; Shan, Shiyao; Ren, Yang; Wu, Jinfang; Cronk, Hannah; Luo, Jin; Zhong, Chuan-Jian

2016-05-19

Here we present the results from a study aimed at clarifying the relationship between the atomic structure and activity of nanocatalysts for chemical reactions driving fuel cells, such as the oxygen reduction reaction (ORR). In particular, using in operando high-energy X-ray diffraction (HE-XRD) we tracked the evolution of the atomic structure and activity of noble metal-transition metal (NM-TM) nanocatalysts for ORR as they function at the cathode of a fully operational proton exchange membrane fuel cell (PEMFC). Experimental HE-XRD data were analysed in terms of atomic pair distribution functions (PDFs) and compared to the current output of the PEMFC, which was also recorded during the experiments. The comparison revealed that under actual operating conditions, NM-TM nanocatalysts can undergo structural changes that differ significantly in both length-scale and dynamics and so can suffer losses in their ORR activity that differ significantly in both character and magnitude. Therefore we argue that strategies for reducing ORR activity losses should implement steps for achieving control not only over the length but also over the time-scale of the structural changes of NM-TM NPs that indeed occur during PEMFC operation. Moreover, we demonstrate how such a control can be achieved and thereby the performance of PEMFCs improved considerably. Last but not least, we argue that the unique capabilities of in operando HE-XRD coupled to atomic PDF analysis to characterize active nanocatalysts inside operating fuel cells both in a time-resolved manner and with atomic level resolution, i.e. in 4D, can serve well the ongoing search for nanocatalysts that deliver more with less platinum.

Biological Redox Cycling Of Iron In Nontronite And Its Potential Application In Nitrate Removal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Linduo; Dong, Hailiang; Kukkadapu, Ravi K.

2015-05-05

Redox cycling of structural Fe in phyllosilicates provides a potential method to remediate nitrate contamination in natural environment. Past research has only studied chemical redox cycles or a single biologically mediated redox cycle of Fe in phyllosilicates. The objective of this research was to study three microbially driven redox cycles of Fe in one phyllosilicate, nontronite (NAu-2). During the reduction phase structural Fe(III) in NAu-2 served as electron acceptor, lactate as electron donor, AQDS as electron shuttle, and dissimilatory Fe(III)-reducing bacteria Shewanella putrefaciens CN32 as mediator in bicarbonate-buffered and PIPES-buffered media. During the oxidation phase, biogenic Fe(II) served an electronmore » donor, nitrate as electron acceptor, and nitrate-dependent Fe(II)-oxidizing bacteria Pseudogulbenkiania sp. strain 2002 as mediator in the same media. For all three cycles, structural Fe in NAu-2 was able to reversibly undergo 3 redox cycles without significant reductive or oxidative dissolution. X-ray diffraction and scanning and transmission electron microscopy revealed that NAu-2 was the dominant residual mineral throughout the 3 redox cycles with some dissolution textures but no significant secondary mineralization. Mössbauer spectroscopy revealed that Fe(II) in bio-reduced samples likely occurred in two distinct environments, at edges and the interior of the NAu-2 structure. Nitrate was completely reduced to nitrogen gas under both buffer conditions and this extent and rate did not change with Fe redox cycles. Mössbauer spectroscopy further revealed that nitrate reduction was coupled to predominant/preferred oxidation of edge Fe(II). These results suggest that structural Fe in phyllosilicates may represent a renewable source to continuously remove nitrate in natural environments.« less

Sequence dependent aggregation of peptides and fibril formation

NASA Astrophysics Data System (ADS)

Hung, Nguyen Ba; Le, Duy-Manh; Hoang, Trinh X.

2017-09-01

Deciphering the links between amino acid sequence and amyloid fibril formation is key for understanding protein misfolding diseases. Here we use Monte Carlo simulations to study the aggregation of short peptides in a coarse-grained model with hydrophobic-polar (HP) amino acid sequences and correlated side chain orientations for hydrophobic contacts. A significant heterogeneity is observed in the aggregate structures and in the thermodynamics of aggregation for systems of different HP sequences and different numbers of peptides. Fibril-like ordered aggregates are found for several sequences that contain the common HPH pattern, while other sequences may form helix bundles or disordered aggregates. A wide variation of the aggregation transition temperatures among sequences, even among those of the same hydrophobic fraction, indicates that not all sequences undergo aggregation at a presumable physiological temperature. The transition is found to be the most cooperative for sequences forming fibril-like structures. For a fibril-prone sequence, it is shown that fibril formation follows the nucleation and growth mechanism. Interestingly, a binary mixture of peptides of an aggregation-prone and a non-aggregation-prone sequence shows the association and conversion of the latter to the fibrillar structure. Our study highlights the role of a sequence in selecting fibril-like aggregates and also the impact of a structural template on fibril formation by peptides of unrelated sequences.

Structural, kinetic and computational investigation of Vitis vinifera DHDPS reveals new insight into the mechanism of lysine-mediated allosteric inhibition.

PubMed

Atkinson, Sarah C; Dogovski, Con; Downton, Matthew T; Czabotar, Peter E; Dobson, Renwick C J; Gerrard, Juliet A; Wagner, John; Perugini, Matthew A

2013-03-01

Lysine is one of the most limiting amino acids in plants and its biosynthesis is carefully regulated through inhibition of the first committed step in the pathway catalyzed by dihydrodipicolinate synthase (DHDPS). This is mediated via a feedback mechanism involving the binding of lysine to the allosteric cleft of DHDPS. However, the precise allosteric mechanism is yet to be defined. We present a thorough enzyme kinetic and thermodynamic analysis of lysine inhibition of DHDPS from the common grapevine, Vitis vinifera (Vv). Our studies demonstrate that lysine binding is both tight (relative to bacterial DHDPS orthologs) and cooperative. The crystal structure of the enzyme bound to lysine (2.4 Å) identifies the allosteric binding site and clearly shows a conformational change of several residues within the allosteric and active sites. Molecular dynamics simulations comparing the lysine-bound (PDB ID 4HNN) and lysine free (PDB ID 3TUU) structures show that Tyr132, a key catalytic site residue, undergoes significant rotational motion upon lysine binding. This suggests proton relay through the catalytic triad is attenuated in the presence of lysine. Our study reveals for the first time the structural mechanism for allosteric inhibition of DHDPS from the common grapevine.

Energy landscapes of the monomer and dimer of the Alzheimer's peptide A β (1 -28 )

NASA Astrophysics Data System (ADS)

Dong, Xiao; Chen, Wei; Mousseau, Normand; Derreumaux, Philippe

2008-03-01

The cytoxicity of Alzheimer's disease has been linked to the self-assembly of the 40 /42 amino acid of the amyloid-β (A β ) peptide into oligomers. To understand the assembly process, it is important to characterize the very first steps of aggregation at an atomic level of detail. Here, we focus on the N-terminal fragment 1-28, known to form fibrils in vitro. Circular dichroism and NMR experiments indicate that the monomer of A β (1 -28 ) is α -helical in a membranelike environment and random coil in aqueous solution. Using the activation-relaxation technique coupled with the OPEP coarse grained force field, we determine the structures of the monomer and of the dimer of A β (1 -28 ) . In agreement with experiments, we find that the monomer is predominantly random coil in character, but displays a non-negligible β -strand probability in the N-terminal region. Dimerization impacts the structure of each chain and leads to an ensemble of intertwined conformations with little β -strand content in the region Leu17-Ala21. All these structural characteristics are inconsistent with the amyloid fibril structure and indicate that the dimer has to undergo significant rearrangement en route to fibril formation.

Deciphering RNA-Recognition Patterns of Intrinsically Disordered Proteins.

PubMed

Srivastava, Ambuj; Ahmad, Shandar; Gromiha, M Michael

2018-05-29

Intrinsically disordered regions (IDRs) and protein (IDPs) are highly flexible owing to their lack of well-defined structures. A subset of such proteins interacts with various substrates; including RNA; frequently adopting regular structures in the final complex. In this work; we have analysed a dataset of protein⁻RNA complexes undergoing disorder-to-order transition (DOT) upon binding. We found that DOT regions are generally small in size (less than 3 residues) for RNA binding proteins. Like structured proteins; positively charged residues are found to interact with RNA molecules; indicating the dominance of electrostatic and cation-π interactions. However, a comparison of binding frequency shows that interface hydrophobic and aromatic residues have more interactions in only DOT regions than in a protein. Further; DOT regions have significantly higher exposure to water than their structured counterparts. Interactions of DOT regions with RNA increase the sheet formation with minor changes in helix forming residues. We have computed the interaction energy for amino acids⁻nucleotide pairs; which showed the preference of His⁻G; Asn⁻U and Ser⁻U at for the interface of DOT regions. This study provides insights to understand protein⁻RNA interactions and the results could also be used for developing a tool for identifying DOT regions in RNA binding proteins.

Predicting crystal structures and properties of matter under extreme conditions via quantum mechanics: The pressure is on

DOE PAGES

Zurek, Eva; Grochala, Wojciech

2014-11-27

Experimental studies of compressed matter are now routinely conducted at pressures exceeding 1 mln atm (100 GPa) and occasionally they even surpass 10 mln atm (1 TPa). The structure and properties of solids that have been so significantly squeezed differ considerably from those know at ambient pressures (1 atm), often times leading to new and unexpected physics. Chemical reactivity is also substantially altered in the extreme pressure regime. In this feature paper we describe how synergy between theory and experiment can pave the road towards new experimental discoveries. Because chemical rules-of-thumb established at 1 atm often fail to predict themore » structures of solids under high pressure, automated crystal structure prediction (CSP) methods have been increasingly employed. After outlining the most important CSP techniques, we showcase a few examples from the recent literature that exemplify just how useful theory can be as an aid in the interpretation of experimental data, describe exciting theoretical predictions that are guiding experiment, and discuss when the computational methods that are currently routinely employed fail. Lastly, we forecast important problems that will be targeted by theory as theoretical methods undergo rapid development, along with the simultaneous increase of computational power.« less

Thermal and magnetic hysteresis associated with martensitic and magnetic phase transformations in Ni52Mn25In16Co7 Heusler alloy

NASA Astrophysics Data System (ADS)

Madiligama, A. S. B.; Ari-Gur, P.; Ren, Y.; Koledov, V. V.; Dilmieva, E. T.; Kamantsev, A. P.; Mashirov, A. V.; Shavrov, V. G.; Gonzalez-Legarreta, L.; Grande, B. H.

2017-11-01

Ni-Mn-In-Co Heusler alloys demonstrate promising magnetocaloric performance for use as refrigerants in magnetic cooling systems with the goal of replacing the lower efficiency, eco-adverse fluid-compression technology. The largest change in entropy occurs when the applied magnetic field causes a merged structural and magnetic transformation and the associated entropy changes of the two transformations works constructively. In this study, magnetic and crystalline phase transformations were each treated separately and the effects of the application of magnetic field on thermal hystereses associated with both structural and magnetic transformations of the Ni52Mn25In16Co7 were studied. From the analysis of synchrotron diffraction data and thermomagnetic measurements, it was revealed that the alloy undergoes both structural (from cubic austenite to a mixture of 7M &5M modulated martensite) and magnetic (ferromagnetic to a low-magnetization phase) phase transformations. Thermal hysteresis is associated with both transformations, and the variation of the thermal hystereses of the magnetic and structural transformations with applied magnetic field is significantly different. Because of the differences between the hystereses loops of the two transformations, they merge only upon heating under a certain magnetic field.

Is it worth packing the head with ice in patients undergoing deep hypothermic circulatory arrest?

PubMed

O'Neill, Bridie; Bilal, Haris; Mahmood, Sarah; Waterworth, Paul

2012-10-01

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was: Is it worth packing the head with ice in patients undergoing deep hypothermic circulatory arrest (DHCA)? Altogether more than 34 papers were found using the reported search, of which 7 represented the best evidence to answer the clinical question, 5 of which were animal studies, 1 was a theoretical laboratory study and 1 study looked at the ability to cool using circulating water 'jackets' in humans. There were no available human studies looking at the neurological outcome with or without topical head cooling with ice without further adjunct methods of cerebral protection. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. Four papers studied animals undergoing DHCA for 45 min-2 h depending on the study design, with or without packing the head with ice. The studies all demonstrated improved cerebral cooling when the head was packed with ice during DHCA. They also illustrated an improved neurological outcome, with better behavioural scores (P < 0.05), and in some, survival, when compared with animals whose heads were not packed in ice. One study examined selective head cooling with the use of packing the head with ice during rewarming after DHCA. However, they demonstrated worse neurological outcomes in these animals, possibly due to the loss of cerebral vasoregulation and cerebral oedema. One study involved a laboratory experiment showing improved cooling using circulating cool water in cryotherapy braces than by using packed ice. They extrapolated that newer devices to cool the head may improve cerebral cooling during DHCA. The final study discussed here demonstrated the use of circulating water to the head in humans undergoing pulmonary endarterectomy. They found that tympanic membrane temperatures could be maintained significantly lower than bladder or rectal temperatures when using circulating water to cool the head. We conclude that topical head cooling with ice is of use during DHCA but not during rewarming following DHCA and that it may be possible to advance topical head cooling techniques using circulating water rather than packed ice.

The impact of training and working conditions on junior doctors’ intention to leave clinical practice

PubMed Central

2014-01-01

Background The shortage of physicians is an evolving problem throughout the world. In this study we aimed to identify to what extent junior doctors’ training and working conditions determine their intention to leave clinical practice after residency training. Methods A prospective cohort study was conducted in 557 junior doctors undergoing residency training in German hospitals. Self-reported specialty training conditions, working conditions and intention to leave clinical practice were measured over three time points. Scales covering training conditions were assessed by structured residency training, professional support, and dealing with lack of knowledge; working conditions were evaluated by work overload, job autonomy and social support, based on the Demand–Control–Support model. Multivariate ordinal logistic regression analyses with random intercept for longitudinal data were applied to determine the odds ratio of having a higher level of intention to leave clinical practice. Results In the models that considered training and working conditions separately to predict intention to leave clinical practice we found significant baseline effects and change effects. After modelling training and working conditions simultaneously, we found evidence that the change effect of job autonomy (OR 0.77, p = .005) was associated with intention to leave clinical practice, whereas for the training conditions, only the baseline effects of structured residency training (OR 0.74, p = .017) and dealing with lack of knowledge (OR 0.74, p = .026) predicted intention to leave clinical practice. Conclusions Junior doctors undergoing specialty training experience high workload in hospital practice and intense requirements in terms of specialty training. Our study indicates that simultaneously improving working conditions over time and establishing a high standard of specialty training conditions may prevent junior doctors from considering leaving clinical practice after residency training. PMID:24942360

Systemic Inflammatory and Th17 Immune Activation among Patients Treated for Lumbar Radiculopathy Exceeds that of Patients Treated for Persistent Postoperative Neuropathic Pain.

PubMed

Shamji, Mohammed F; Guha, Daipayan; Paul, Darcia; Shcharinsky, Alina

2017-09-01

The pathophysiology of lumbar radiculopathy includes both mechanical compression and biochemical irritation of apposed neural elements. Inflammatory and immune cytokines have been implicated, induced by systemic exposure of immune-privileged intervertebral disc tissue. Surgical intervention provides improved symptoms and quality of life, but persistent postoperative neuropathic pain (PPNP) afflicts a significant fraction of patients. To compare the inflammatory and immune phenotypes among patients undergoing structural surgery for lumbar radiculopathy and spinal cord stimulation for neuropathic pain. Consecutive patients undergoing surgical intervention for lumbar radiculopathy or neuropathic pain were studied. Demographic data included age, gender, and VAS and neuropathic pain scores. Serum was evaluated for cytokine levels (IL-6, Il-17, TNF-α) and cellular content [white blood cell (WBC)/differential, lymphocyte subtypes]. The primary analysis differentiated molecular and cellular profiles between radiculopathy and neuropathic pain patients. Subgroup analysis within the surgical radiculopathy population compared those patients achieving relief of symptoms and those with PPNP. Heightened IL-6, Il-17, and TNF-α levels were observed for the lumbar radiculopathy group compared with the neuropathic pain group. This was complemented by higher WBC count and a greater fraction of Th17 lymphocytes among radiculopathy patients. In the lumbar discectomy subgroup, pain relief was seen among patients with preoperatively elevated IL-17 levels. Those patients with PPNP refractory to surgical discectomy exhibited normal cytokine levels. Differences in Th17 immune activation are seen among radiculopathy and neuropathic pain patients. These cellular and molecular profiles may be translated into biomarkers to improve patient selection for structural spine surgery. Copyright © 2017 by the Congress of Neurological Surgeons

Plasmonic Structures for CMOS Photonics and Control of Spontaneous Emission

DTIC Science & Technology

2013-04-01

structures; v) developed CMOS Si photonic switching device based on the vanadium dioxide ( VO2 ) phase transition. vi) also engaged in a partnership with...CMOS Si photonic switching device based on the vanadium dioxide ( VO2 ) phase transition. vii. exploring approaches to enhance spontaneous emission in...size and bandwidth, we are exploring phase-change materials and, in particular, vanadium dioxide. VO2 undergoes an insulator-to-metal phase transition

Combining the Finite Element Method with Structural Connectome-based Analysis for Modeling Neurotrauma: Connectome Neurotrauma Mechanics

PubMed Central

Kraft, Reuben H.; Mckee, Phillip Justin; Dagro, Amy M.; Grafton, Scott T.

2012-01-01

This article presents the integration of brain injury biomechanics and graph theoretical analysis of neuronal connections, or connectomics, to form a neurocomputational model that captures spatiotemporal characteristics of trauma. We relate localized mechanical brain damage predicted from biofidelic finite element simulations of the human head subjected to impact with degradation in the structural connectome for a single individual. The finite element model incorporates various length scales into the full head simulations by including anisotropic constitutive laws informed by diffusion tensor imaging. Coupling between the finite element analysis and network-based tools is established through experimentally-based cellular injury thresholds for white matter regions. Once edges are degraded, graph theoretical measures are computed on the “damaged” network. For a frontal impact, the simulations predict that the temporal and occipital regions undergo the most axonal strain and strain rate at short times (less than 24 hrs), which leads to cellular death initiation, which results in damage that shows dependence on angle of impact and underlying microstructure of brain tissue. The monotonic cellular death relationships predict a spatiotemporal change of structural damage. Interestingly, at 96 hrs post-impact, computations predict no network nodes were completely disconnected from the network, despite significant damage to network edges. At early times () network measures of global and local efficiency were degraded little; however, as time increased to 96 hrs the network properties were significantly reduced. In the future, this computational framework could help inform functional networks from physics-based structural brain biomechanics to obtain not only a biomechanics-based understanding of injury, but also neurophysiological insight. PMID:22915997

Redox-linked Conformational Dynamics in Apoptosis Inducing Factor

PubMed Central

Sevrioukova, Irina F.

2009-01-01

Apoptosis inducing factor (AIF) is a bifunctional mitochondrial flavoprotein critical for energy metabolism and induction of caspase-independent apoptosis, whose exact role in normal mitochondria remains unknown. Upon reduction with NADH, AIF undergoes dimerization and forms tight, long-lived FADH2-NAD charge-transfer complexes (CTC) proposed to be functionally important. To get a deeper insight into structure/function relations and redox mechanism of this vitally important protein, we determined the x-ray structures of oxidized and NADH-reduced forms of naturally folded recombinant murine AIF. Our structures reveal that CTC with the pyridine nucleotide is stabilized by (i) π-stacking interactions between coplanar nicotinamide, isoalloxazine and Phe309 rings, (ii) rearrangement of multiple aromatic residues in the C-terminal domain, likely serving as an electron delocalization site, and (iii) an extensive hydrogen-bonding network involving His453, a key residue undergoing a conformational switch to directly interact and orient the nicotinamide in position optimal for charge transfer. Via the His453-containing peptide, redox changes in the active site are transmitted to the surface, promoting AIF dimerization and restricting access to a primary nuclear localization signal through which the apoptogenic form is transported to the nucleus. Structural findings agree with the biochemical data and support the hypothesis that both normal and apoptogenic functions of AIF are controlled by NADH. PMID:19447115

Preliminary findings on biomarker levels from extracerebral sources in patients undergoing trauma surgery: Potential implications for TBI outcome studies.

PubMed

Wolf, H; Krall, C; Pajenda, G; Hajdu, S; Widhalm, H; Leitgeb, J; Sarahrudi, K

2016-01-01

Despite several experimental studies on the role of S100B and NSE in fractures, no studies on the influence of surgery on the biomarker serum levels have been performed yet. The serum levels of S100B and NSE were analysed in patients with fractures that were located in the spine (group 1, n = 35) or in the lower extremity (group 2, n = 32) pre- and post-operatively. The mean S100B serum level showed a significant increase (p = 0.04) post-surgery in the patients of group 1. In patients undergoing acute surgery (< 24 hours) the mean S100B serum level was 0.23 ± 0.22 μg L(-1) pre-operatively and 1.24 ± 1.38 μg L(-1) post-operatively. Likewise, the mean S100B serum level significantly increased in group 2 after surgery (p < 0.0001). In this group patients undergoing acute surgery showed a mean S100B serum level of 0.23 ± 0.14 μg L(-1) and 1.11 ± 0.73 μg L(-1) pre- and post-operatively. This study demonstrates significant alterations of the biomarker S100B serum levels in patients undergoing surgery. Higher S100B serum levels were found within 24 hours and might be related to the acute fracture. The NSE serum levels were unchanged and this biomarker may offer the probability to serve as a future outcome predictor in studies with patients with traumatic brain injury and additional extracerebral injuries.

Effects of Peer-Facilitated, Video-Based and Combined Peer-and-Video Education on Anxiety Among Patients Undergoing Coronary Angiography: Randomised controlled trial.

PubMed

Habibzadeh, Hosein; Milan, Zahra D; Radfar, Moloud; Alilu, Leyla; Cund, Audrey

2018-02-01

Coronary angiography can be stressful for patients and anxiety-caused physiological responses during the procedure increase the risk of dysrhythmia, coronary artery spasms and rupture. This study therefore aimed to investigate the effects of peer, video and combined peer-and-video training on anxiety among patients undergoing coronary angiography. This single-blinded randomised controlled clinical trial was conducted at two large educational hospitals in Iran between April and July 2016. A total of 120 adult patients undergoing coronary angiography were recruited. Using a block randomisation method, participants were assigned to one of four groups, with those in the control group receiving no training and those in the three intervention groups receiving either peer-facilitated training, video-based training or a combination of both. A Persian-language validated version of the State-Trait Anxiety Inventory was used to measure pre- and post-intervention anxiety. There were no statistically significant differences in mean pre-intervention anxiety scores between the four groups (F = 0.31; P = 0.81). In contrast, there was a significant reduction in post-intervention anxiety among all three intervention groups compared to the control group (F = 27.71; P <0.01); however, there was no significant difference in anxiety level in terms of the type of intervention used. Peer, video and combined peer-and-video education were equally effective in reducing angiography-related patient anxiety. Such techniques are recommended to reduce anxiety amongst patients undergoing coronary angiography in hospitals in Iran.

Effect of virtual reality distraction on pain among patients with hand injury undergoing dressing change.

PubMed

Guo, Chunlan; Deng, Hongyan; Yang, Jian

2015-01-01

To assess the effect of virtual reality distraction on pain among patients with a hand injury undergoing a dressing change. Virtual reality distraction can effectively alleviate pain among patients undergoing a dressing change. Clinical research has not addressed pain control during a dressing change. A randomised controlled trial was performed. In the first dressing change sequence, 98 patients were randomly divided into an experimental group and a control group, with 49 cases in each group. Pain levels were compared between the two groups before and after the dressing change using a visual analog scale. The sense of involvement in virtual environments was measured using the Pearson correlation coefficient analysis, which determined the relationship between the sense of involvement and pain level. The difference in visual analog scale scores between the two groups before the dressing change was not statistically significant (t = 0·196, p > 0·05), but the scores became statistically significant after the dressing change (t = -30·792, p < 0·01). The correlation between the sense of involvement in a virtual environment and pain level during the dressing was statistically significant (R(2) = 0·5538, p < 0·05). Virtual reality distraction can effectively alleviate pain among patients with a hand injury undergoing a dressing change. Better results can be obtained by increasing the sense of involvement in a virtual environment. Virtual reality distraction can effectively relieve pain without side effects and is not reliant on a doctor's prescription. This tool is convenient for nurses to use, especially when analgesics are unavailable. © 2014 John Wiley & Sons Ltd.

The Effect of Music on Anxiety and Cardiovascular Indices in Patients Undergoing Coronary Artery Bypass Graft: A Randomized Controlled Trial

PubMed Central

Heidari, Saeide; Babaii, Atye; Abbasinia, Mohammad; Shamali, Mahdi; Abbasi, Mohammad; Rezaei, Mahboobe

2015-01-01

Background: The instability of cardiovascular indices and anxiety disorders are common among patients undergoing coronary artery bypass graft (CABG) and could interfere with their recovery. Therefore, improving the cardiovascular indices and anxiety is essential. Objectives: This study aimed to investigate the effect of music therapy on anxiety and cardiovascular indices in patients undergoing CABG. Patients and Methods: In this randomized controlled trial, 60 patients hospitalized in the cardiovascular surgical intensive care unit of Shahid Beheshti Hospital in Qom city, Iran, in 2013 were selected using a consecutive sampling method and randomly allocated into the experimental and control groups. In the experimental group, patients received 30 minutes of light music, whereas in the control group, patients had 30 minutes of rest in bed. The cardiovascular indices and anxiety were measured immediately before, immediately after and half an hour after the study. Data were analyzed using the chi-square test and repeated measures analysis of variance. Results: Compared to the immediately before intervention, the mean anxiety scores immediately after and 30 minutes after the intervention were significantly lower in the experimental group (P < 0.037) while it did not significantly change in the control group. However, there were no significant differences regarding the cardiovascular indices in the three consecutive measurements (P > 0.05). Conclusions: Music therapy is effective in decreasing anxiety among patients undergoing CABG. However, the intervention was not effective on cardiovascular indices. Music can effectively be used as a non-pharmacological method to manage anxiety after CABG. PMID:26835471

Barriers to surgical care in Nepal.

PubMed

van Loenhout, Joris Adriaan Frank; Delbiso, Tefera Darge; Gupta, Shailvi; Amatya, Kapendra; Kushner, Adam L; Gil Cuesta, Julita; Guha-Sapir, Debarati

2017-01-23

Various barriers exist that preclude individuals from undergoing surgical care in low-income countries. Our study assessed the main barriers in Nepal, and identified individuals most at risk for not receiving required surgical care. A countrywide survey, using the Surgeons OverSeas Assessment of Surgical Need (SOSAS) survey tool, was carried out in 2014, surveying 2,695 individuals with a response rate of 97%. Our study used data from a subset, namely individuals who required surgical care in the last twelve months. Data were collected on individual characteristics, transport characteristics, and reasons why individuals did not undergo surgical care. Of the 2,695 individuals surveyed, 207 individuals needed surgical care at least once in the previous 12 months. The main reasons for not undergoing surgery were affordability (n = 42), accessibility (n = 42) and fear/no trust (n = 34). A factor significantly associated with affordability was having a low education (OR = 5.77 of having no education vs. having secondary education). Living in a rural area (OR = 2.59) and a long travel time to a secondary and tertiary health facility (OR = 1.17 and 1.09, respectively) were some of the factors significantly associated with accessibility. Being a woman was significantly associated with fear/no trust (OR = 3.54). More than half of the individuals who needed surgical care did not undergo surgery due to affordability, accessibility, or fear/no trust. Providing subsidised transport, introducing mobile surgical clinics or organising awareness raising campaigns are measures that could be implemented to overcome these barriers to surgical care.

Computer tablet distraction reduces pain and anxiety in pediatric burn patients undergoing hydrotherapy: A randomized trial.

PubMed

Burns-Nader, Sherwood; Joe, Lindsay; Pinion, Kelly

2017-09-01

Distraction is often used in conjunction with analgesics to minimize pain in pediatric burn patients during treatment procedures. Computer tablets provide many options for distraction items in one tool and are often used during medical procedures. Few studies have examined the effectiveness of tablet distraction in improving the care of pediatric burn patients. This study examines the effectiveness of tablet distraction provided by a child life specialist to minimize pain and anxiety in pediatric burn patients undergoing hydrotherapy. Thirty pediatric patients (4-12) undergoing hydrotherapy for the treatment of burns participated in this randomized clinical trial. The tablet distraction group received tablet distraction provided by a child life specialist while those in the control group received standard care. Pain was assessed through self-reports and observation reports. Anxiety was assessed through behavioral observations. Length of procedure was also recorded. Nurses reported significantly less pain for the tablet distraction group compared to the control group. There was no significant difference between groups on self-reported pain. The tablet distraction group displayed significantly less anxiety during the procedure compared to the control group. Also, the tablet distraction group returned to baseline after the procedure while those in the control group displayed higher anxiety post-procedure. There was no difference in the length of the procedure between groups. These findings suggest tablet distraction provided by a child life specialist may be an effective method for improving pain and anxiety in children undergoing hydrotherapy treatment for burns. Copyright © 2017 Elsevier Ltd and ISBI. All rights reserved.

Study of the micro-structural properties of RISUG--a newly developed male contraceptive.

PubMed

Kumar, Sunil; Roy, Sohini; Chaudhury, Koel; Sen, Prasenjit; Guha, Sujoy K

2008-07-01

A new male contraceptive given the name RISUG (an acronym for reversible inhibition of sperm under guidance) and presently undergoing advanced clinical trials has been developed. When injected into the lumen of the vas deferens, its polyelectrolytic nature induces a surface charge imbalance on sperm membrane system leading to the leakage of enzymes essential for fertilization. Contact mode atomic force microscopy (AFM) has been used to analyze quantitatively the micro-structural properties of RISUG and its precipitate in various systems. Hydrolysis of the contraceptive gel resulted in the formation of pores of varying dimensions. RISUG being a highly charged molecule, as evident from zeta potential measurements, has a tendency to form a complex with ionic biomolecules present in the seminal plasma. This is supported by the experimental observations using AFM. This RISUG-biomolecule complex possibly acts as an ionic trap for spermatozoa passing through the vas deferens. Micro-structural properties of RISUG including amplitude (root mean square, peak-to-valley distance, skewness and kurtosis) and spatial roughness have been studied to understand its response to various physiological conditions. Significant alterations in the surface charge distribution of the sperm cell is observed on exposure to RISUG. 2007 Wiley Periodicals, Inc.

Food emulsions as delivery systems for flavor compounds: A review.

PubMed

Mao, Like; Roos, Yrjö H; Biliaderis, Costas G; Miao, Song

2017-10-13

Food flavor is an important attribute of quality food, and it largely determines consumer food preference. Many food products exist as emulsions or experience emulsification during processing, and therefore, a good understanding of flavor release from emulsions is essential to design food with desirable flavor characteristics. Emulsions are biphasic systems, where flavor compounds are partitioning into different phases, and the releases can be modulated through different ways. Emulsion ingredients, such as oils, emulsifiers, thickening agents, can interact with flavor compounds, thus modifying the thermodynamic behavior of flavor compounds. Emulsion structures, including droplet size and size distribution, viscosity, interface thickness, etc., can influence flavor component partition and their diffusion in the emulsions, resulting in different release kinetics. When emulsions are consumed in the mouth, both emulsion ingredients and structures undergo significant changes, resulting in different flavor perception. Special design of emulsion structures in the water phase, oil phase, and interface provides emulsions with great potential as delivery systems to control flavor release in wider applications. This review provides an overview of the current understanding of flavor release from emulsions, and how emulsions can behave as delivery systems for flavor compounds to better design novel food products with enhanced sensorial and nutritional attributes.

Magnetic and optical properties of carbon and silicon decorated free standing buckled germanene: A DFT approach

NASA Astrophysics Data System (ADS)

Dhar, Namrata; Jana, Debnarayan

2018-04-01

Ab initio magnetic and optical properties of group IV elements (carbon (C) and silicon (Si)) decorated free standing (FS) buckled germanene systems have been employed theoretically. Our study elucidates that, decoration of these elements in proper sites with suitable concentrations form dynamically stable configurations. Band structure is modified due to decoration of these atoms in Ge-nanosheet and pristine semi-metallic germanene undergoes to semiconductors with a finite amount of bandgap. Interestingly, this bandgap value meets closely the requirement of gap for field effect transistor (FET) applications. Moreover, significant magnetic moment is induced in non-magnetic germanene for C decorated structure and ground state in anti-ferromagnetic in nature for this structure. Along with magnetic property, optical properties like dielectric functions, optical absorption, electron energy loss spectra (EELS), refractive index and reflectivity of these systems have also been investigated. Maximum number of plasma frequencies appear for Si decorated configuration considering both parallel and perpendicular polarizations. In addition, birefringence characteristics of these configurations have also been studied as it is an important parameter in various applications of optical devices, liquid crystal displays, light modulators etc.

Ab Initio Study of Electronic Excitation Effects on SrTiO 3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Shijun; Zhang, Yanwen; Weber, William J.

Interaction of energetic ions or lasers with solids often induces electronic excitations that may modify material properties significantly. In this study, effects of electronic excitations on strontium titanate SrTiO 3 (STO) are investigated based on first-principles calculations. The lattice structure, electronic properties, lattice vibrational frequencies, and dynamical stabilities are studied in detail. The results suggest that electronic excitation induces charge redistribution that is mainly observed in Ti–O bonds. The electronic band gap increases with increasing electronic excitation, as excitation mainly induces depopulation of Ti 3d states. Phonon analysis indicates that there is a large phonon band gap induced by electronicmore » excitation because of the changes in the vibrational properties of Ti and O atoms. In addition, a new peak appears in the phonon density of states with imaginary frequencies, an indication of lattice instability. Further dynamics simulations confirm that STO undergoes transition to an amorphous structure under strong electronic excitations. In conclusion, the optical properties of STO under electronic excitation are consistent with the evolution of atomic and electronic structures, which suggests a possibility to probe the properties of STO in nonequilibrium state using optical measurement.« less

Electroplating of aluminium microparticles with nickel to synthesise reactive core-shell structures for thermal joining applications

NASA Astrophysics Data System (ADS)

Schreiber, S.; Zaeh, M. F.

2018-06-01

Reactive particles represent a promising alternative for effectively joining components with freeform surfaces and different material properties. While the primary application of reactive systems is combustion synthesis for the production of high-performance alloys, the highly exothermic reaction can also be used to firmly bond thermosensitive joining partners. Core-shell structures are of special interest, since they function as separate microreactors. In this paper, a method to synthesise reactive nickel-aluminium core-shell structures via a two-step plating process is described. Based on an electroless process, the natural oxide layer of the aluminium particles is removed and substituted with a thin layer of nickel. Subsequently, the pre-treated particles are electroplated with nickel. The high reactivity of aluminium and the oxide layer play a significant role in adjusting the process parameters of the Watts bath. Additionally, the developed experimental set-up is introduced and the importance of process control is shown. In order to achieve reproducible results, the electroplating process was automated. Ignition tests with electromagnetic waves demonstrated that the particles undergo an exothermic reaction. Therefore, they can be used as a heat source in thermal joining applications.

Ab Initio Study of Electronic Excitation Effects on SrTiO 3

DOE PAGES

Zhao, Shijun; Zhang, Yanwen; Weber, William J.

2017-11-14

Interaction of energetic ions or lasers with solids often induces electronic excitations that may modify material properties significantly. In this study, effects of electronic excitations on strontium titanate SrTiO 3 (STO) are investigated based on first-principles calculations. The lattice structure, electronic properties, lattice vibrational frequencies, and dynamical stabilities are studied in detail. The results suggest that electronic excitation induces charge redistribution that is mainly observed in Ti–O bonds. The electronic band gap increases with increasing electronic excitation, as excitation mainly induces depopulation of Ti 3d states. Phonon analysis indicates that there is a large phonon band gap induced by electronicmore » excitation because of the changes in the vibrational properties of Ti and O atoms. In addition, a new peak appears in the phonon density of states with imaginary frequencies, an indication of lattice instability. Further dynamics simulations confirm that STO undergoes transition to an amorphous structure under strong electronic excitations. In conclusion, the optical properties of STO under electronic excitation are consistent with the evolution of atomic and electronic structures, which suggests a possibility to probe the properties of STO in nonequilibrium state using optical measurement.« less

Loop conformation and dynamics of the Escherichia coli HPPK apo-enzyme and its binary complex with MgATP.

PubMed

Yang, Rong; Lee, Matthew C; Yan, Honggao; Duan, Yong

2005-07-01

Comparison of the crystallographic and NMR structures of 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK) suggests that the enzyme may undergo significant conformational change upon binding to its first substrate, ATP. Two of the three surface loops (loop 2 and loop 3) accounting for most of the conformational differences appear to be confined by crystal contacts, raising questions about the putative large-scale induced-fit conformational change of HPPK and the functional roles of the conserved side-chain residues on the loops. To investigate the loop dynamics in crystal-free environment, we carried out molecular dynamics and locally enhanced sampling simulations of the apo-enzyme and the HPPK.MgATP complex. Our simulations showed that the crystallographic B-factors underestimated the loop dynamics considerably. We found that the open-conformation of loop 3 in the binary complex is accessible to the apo-enzyme and is the favored conformation in solution phase. These results revise our previous view of HPPK-substrate interactions and the associated functional mechanism of conformational change. The lessons learned here offer valuable structural insights into the workings of HPPK and should be useful for structure-based drug design.

Multivariate Analysis of Conformational Changes Induced by Macromolecular Interactions

NASA Astrophysics Data System (ADS)

Mitra, Indranil; Alexov, Emil

2009-11-01

Understanding protein-protein binding and associated conformational changes is critical for both understanding thermodynamics of protein interactions and successful drug discovery. Our study focuses on computational analysis of plausible correlations between induced conformational changes and set of biophysical characteristics of interacting monomers. It was done by comparing 3D structures of unbound and bound monomers to calculate the RMSD which is used as measure of the structural changed induced by the binding. We correlate RMSD with volumetric and interfacial charge of the monomers, the amino acid composition, the energy of binding, and type of amino acids at the interface. as predictors. The data set was analyzed with SVM in R & SPSS which is trained on a combination of a new robust evolutionary conservation signal with the monomeric properties to predict the induced RMSD. The goal of this study is to undergo parametric tests and heirchiacal cluster and discriminant multivariate analysis to find key predictors which will be used to develop algorithm to predict the magnitude of conformational changes provided by the structure of interacting monomers. Results indicate that the most promising predictor is the net charge of the monomers, however, other parameters as the type of amino acids at the interface have significant contribution as well.

A new structural framework for integrating replication protein A into DNA processing machinery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brosey, Chris A; Yan, Chunli; Tsutakawa, Susan E

2013-01-01

By coupling the protection and organization of ssDNA with the recruitment and alignment of DNA processing factors, Replication Protein A (RPA) lies at the heart of dynamic multi-protein DNA processing machinery. Nevertheless, how RPA manages to coordinate the biochemical functions of its eight domains remains unknown. We examined the structural biochemistry of RPA s DNA binding activity, combining small-angle x-ray and neutron scattering with all-atom molecular dynamics simulations to investigate the architecture of RPA s DNA-binding core. It has been long held that RPA engages ssDNA in three stages, but our data reveal that RPA undergoes two rather than threemore » transitions as it binds ssDNA. In contrast to previous models, RPA is more compact when fully engaged on 20-30 nucleotides of ssDNA than when DNA-free, and there is no evidence for significant population of a highly compacted structure in the initial 8-10 nucleotide binding mode. These results provide a new framework for understanding the integration of ssDNA into DNA processing machinery and how binding partners may manipulate RPA architecture to gain access to the substrate.« less

Structural basis of viral invasion: lessons from paramyxovirus F

PubMed Central

Lamb, Robert A.; Jardetzky, Theodore S.

2007-01-01

Summary The structures of glycoproteins that mediate enveloped virus entry into cells have revealed dramatic structural changes that accompany membrane fusion and provided mechanistic insights into this process. The group of class I viral fusion proteins includes the influenza hemagglutinin, paramyxovirus F, HIV env and other mechanistically related fusogens, but these proteins are unrelated in sequence and exhibit clearly distinct structural features. Recently determined crystal structures of the paramyxovirus F protein in two conformations, representing prefusion and postfusion states, reveal a novel protein architecture that undergoes large-scale, irreversible refolding during membrane fusion, extending our understanding of this diverse group of membrane fusion machines. PMID:17870467

Cytogenetic analysis of children under long-term antibacterial therapy with nitroheterocyclic compound furagin.

PubMed

Slapsyte, G; Jankauskiene, A; Mierauskiene, J; Lazutka, J R

2001-04-05

Cytogenetic analysis of chromosome aberrations (CAs) and sister chromatid exchanges (SCEs) was performed in 109 blood samples from 95 pediatric patients with urinary tract infections (UTIs). Children were exposed to diagnostic levels of X-rays during voiding cystourethrography and subsequently treated for one to 12 months with low doses of furagin - N-(5-nitro-2-furyl)-allylidene-1-aminohydantoin. Furagin is 2-substituted 5-nitrofuran, chemically and structurally similar to well-known antibacterial compound nitrofurantoin. Increased frequencies of CAs were found in children undergoing voiding cystourethrography as compared with the unexposed, acentric fragments being the most frequent alteration (2.03 versus 0.88 per 100 cells, P=0.006). However, a significant decrease in the frequency of acentric fragments was determined with the time elapsed since X-ray examination was performed. A time-independent increase in SCE frequency was found in lymphocytes of children treated with furagin. Total CA frequency did not differ significantly between groups of children with various duration of furagin treatment. However, frequency of chromatid exchanges (triradials and quadriradials) increased significantly with duration of treatment.

Safety and efficacy of hysteroscopic sterilization compared with laparoscopic sterilization: an observational cohort study.

PubMed

Mao, Jialin; Pfeifer, Samantha; Schlegel, Peter; Sedrakyan, Art

2015-10-13

To compare the safety and efficacy of hysteroscopic sterilization with the "Essure" device with laparoscopic sterilization in a large, all-inclusive, state cohort. Population based cohort study. Outpatient interventional setting in New York State. Women undergoing interval sterilization procedure, including hysteroscopic sterilization with Essure device and laparoscopic surgery, between 2005 and 2013. Safety events within 30 days of procedures; unintended pregnancies and reoperations within one year of procedures. Mixed model accounting for hospital clustering was used to compare 30 day and 1 year outcomes, adjusting for patient characteristics and other confounders. Time to reoperation was evaluated using frailty model for time to event analysis. We identified 8048 patients undergoing hysteroscopic sterilization and 44,278 undergoing laparoscopic sterilization between 2005 and 2013 in New York State. There was a significant increase in the use of hysteroscopic procedures during this period, while use of laparoscopic sterilization decreased. Patients undergoing hysteroscopic sterilization were older than those undergoing laparoscopic sterilization and were more likely to have a history of pelvic inflammatory disease (10.3% v 7.2%, P<0.01), major abdominal surgery (9.4% v 7.9%, P<0.01), and cesarean section (23.2% v 15.4%, P<0.01). At one year after surgery, hysteroscopic sterilization was not associated with a higher risk of unintended pregnancy (odds ratio 0.84 (95% CI 0.63 to 1.12)) but was associated with a substantially increased risk of reoperation (odds ratio 10.16 (7.47 to 13.81)) compared with laparoscopic sterilization. Patients undergoing hysteroscopic sterilization have a similar risk of unintended pregnancy but a more than 10-fold higher risk of undergoing reoperation compared with patients undergoing laparoscopic sterilization. Benefits and risks of both procedures should be discussed with patients for informed decisions making. © Mao et al 2015.

[Changes in the distance between carina and orotracheal tube during open or videolaparoscopic bariatric surgery].

PubMed

de Figueiredo Locks, Giovani; Simões de Almeida, Maria Cristina; Sperotto Ceccon, Maurício; Campos Pastório, Karen Adriana

2015-01-01

To examine whether there are changes in the distance between the orotracheal tubeand carina induced by orthostatic retractor placement or by pneumoperitoneum insufflation in obese patients undergoing gastroplasty. 60 patients undergoing bariatric surgery by two techniques: open (G1) or videola-paroscopic (G2) gastroplasty were studied. After tracheal intubation, adequate ventilation of both hemitoraxes was confirmed by lung auscultation. The distance orotracheal tube-carina was estimated with the use of a fiber bronchoscope before and after installation of orthostatic retractors in G1 or before and after insufflation of pneumoperitoneum in patients in G2. G1 was composed of 22 and G2 of 38 patients. No cases of endobronchial intubationwere detected in either group. The mean orotracheal tube-carina distance variation was estimated in -0.03 cm (95% CI 0.06 to -0.13) in the group of patients undergoing open gastroplastyand in -0.42 cm (95% CI -0.56 to -1.4) in the group of patients undergoing videolaparoscopic gastroplasty. The extremes of variation in each group were: 0.5 cm to -1.6 cm in patients under-going open surgery and 0.1 cm to -2.2 cm in patients undergoing videolaparoscopic surgery. There was no significant change in orotracheal tube-CA distance after placementof orthostatic retractors in patients undergoing open gastroplasty. There was a reduction inorotracheal tube-CA distance after insufflation of pneumoperitoneum in patients undergoing videolaparoscopic gastroplasty. We recommend attention to lung auscultation and to signals of ventilation monitoring and reevaluation of orotracheal tube placement after peritoneal insufflation. Copyright © 2014 Sociedade Brasileira de Anestesiologia. Publicado por Elsevier Editora Ltda. All rights reserved.

Changes in the distance between carina and orotracheal tube during open or videolaparoscopic bariatric surgery.

PubMed

de Figueiredo Locks, Giovani; Simões de Almeida, Maria Cristina; Sperotto Ceccon, Maurício; Campos Pastório, Karen Adriana

2015-01-01

To examine whether there are changes in the distance between the orotracheal tube and carina induced by orthostatic retractor placement or by pneumoperitoneum insufflation in obese patients undergoing gastroplasty. 60 patients undergoing bariatric surgery by two techniques: open (G1) or videolaparoscopic (G2) gastroplasty were studied. After tracheal intubation, adequate ventilation of both hemitoraxes was confirmed by lung auscultation. The distance orotracheal tube-carina was estimated with the use of a fiber bronchoscope before and after installation of orthostatic retractors in G1 or before and after insufflation of pneumoperitoneum in patients in G2. G1 was composed of 22 and G2 of 38 patients. No cases of endobronchial intubation were detected in either group. The mean orotracheal tube-carina distance variation was estimated in -0.03cm (95% CI 0.06 to -0.13) in the group of patients undergoing open gastroplasty and in -0.42cm (95% CI -0.56 to -1.4) in the group of patients undergoing videolaparoscopic gastroplasty. The extremes of variation in each group were: 0.5cm to -1.6cm in patients undergoing open surgery and 0.1cm to -2.2cm in patients undergoing videolaparoscopic surgery. There was no significant change in orotracheal tube-CA distance after placement of orthostatic retractors in patients undergoing open gastroplasty. There was a reduction in orotracheal tube-CA distance after insufflation of pneumoperitoneum in patients undergoing videolaparoscopic gastroplasty. We recommend attention to lung auscultation and to signals of ventilation monitoring and reevaluation of orotracheal tube placement after peritoneal insufflation. Copyright © 2014 Sociedade Brasileira de Anestesiologia. Published by Elsevier Editora Ltda. All rights reserved.

Effects of recombinant human activated protein C on the fibrinolytic system of patients undergoing conventional or tight glycemic control.

PubMed

Polli, F; Savioli, M; Cugno, M; Taccone, P; Bellani, G; Spanu, P; Pesenti, A; Iapichino, G; Gattinoni, L

2009-01-01

Recombinant human activated protein C (rh-APC) and tight glycemic control (TGC) have been shown to reduce mortality in septic patients. Both interventions can reduce the plasma concentration and/or activity of the most powerful suppressor of fibrinolysis, plasminogen activator inhibitor-1 (PAI-1). Our aim was to evaluate the effects on the fibrinolytic system after the administration of rh-APC in septic patients undergoing conventional or TGC. Posthoc analysis of data was collected from 90 patients with severe sepsis/septic shock, randomized to either conventional or TGC groups. Independent of these treatments, patients with at least two organ dysfunctions simultaneously received rh-APC. Plasma levels of multiple biochemical markers for fibrinolysis, coagulation, and inflammation were determined every day for the 1st week and then on study days 9, 11, 13, 18, 23, and 28. Clinical data and sepsis-related organ failure assessment (SOFA) scores were also recorded. Patients who had received rh-APC exhibited significantly more impairments in fibrinolysis at baseline (PAI-1 activity 49.76 [24.61-71.82] vs 21.92 [6.47-55-83] IU/mL, P=0.03). The reductions in plasma PAI-1 activity over time associated with rh-APC treatment were different according to whether the treatment was administered to patients undergoing conventional or TGC (P=0.01). However, the most prominent reductions were in patients undergoing conventional glycemic control. Significant interactions between the two study interventions were also found for PAI-1 concentration (P<0.001), C-reactive protein (P=0.02), and interleukin-6 levels (P<0.001). Both rh-APC and TGC appear to improve fibrinolysis in septic patients. The reduction in the impairment of fibrinolysis associated with rh-APC treatment seems greater in patients undergoing conventional glycemic control than in those undergoing TGC.

Ferromagnetic ordering in superatomic solids.

PubMed

Lee, Chul-Ho; Liu, Lian; Bejger, Christopher; Turkiewicz, Ari; Goko, Tatsuo; Arguello, Carlos J; Frandsen, Benjamin A; Cheung, Sky C; Medina, Teresa; Munsie, Timothy J S; D'Ortenzio, Robert; Luke, Graeme M; Besara, Tiglet; Lalancette, Roger A; Siegrist, Theo; Stephens, Peter W; Crowther, Andrew C; Brus, Louis E; Matsuo, Yutaka; Nakamura, Eiichi; Uemura, Yasutomo J; Kim, Philip; Nuckolls, Colin; Steigerwald, Michael L; Roy, Xavier

2014-12-03

In order to realize significant benefits from the assembly of solid-state materials from molecular cluster superatomic building blocks, several criteria must be met. Reproducible syntheses must reliably produce macroscopic amounts of pure material; the cluster-assembled solids must show properties that are more than simply averages of those of the constituent subunits; and rational changes to the chemical structures of the subunits must result in predictable changes in the collective properties of the solid. In this report we show that we can meet these requirements. Using a combination of magnetometry and muon spin relaxation measurements, we demonstrate that crystallographically defined superatomic solids assembled from molecular nickel telluride clusters and fullerenes undergo a ferromagnetic phase transition at low temperatures. Moreover, we show that when we modify the constituent superatoms, the cooperative magnetic properties change in predictable ways.

REFORMATION OF NUCLEOLI AFTER ETHIONE-INDUCED FRAGMENTATION IN THE ABSENCE OF SIGNIFICANT PROTEIN SYNTHESIS

PubMed Central

Shinozuka, Hisashi; Farber, Emmanuel

1969-01-01

The rat liver nucleolus, after fragmentation induced by ethionine treatment, has been found to undergo complete reformation by adenine in the presence of a dose of cycloheximide sufficient to cause inhibition of protein synthesis by 90–95%. In contrast, actinomycin D given along with adenine was followed by the appearance of a small compact mass containing only the fibrillar component with no evident granules. This structure resembled pseudonucleoli seen in the anucleolate mutant of Xenopus laevis or in certain early stages of amphibian oocytes. Actinomycin D administered 2 hr after adenine induced a segregation of the fibrillar and granular components of nucleoli similar to that induced in the normal nucleolus. The implications of these findings in relation to nucleolar organization are briefly discussed. PMID:5775789

SELECTIVE ADVANTAGE OF RECOMBINATION IN EVOLVING PROTEIN POPULATIONS: A LATTICE MODEL STUDY

PubMed Central

WILLIAMS, PAUL D.; POLLOCK, DAVID D.

2010-01-01

Recent research has attempted to clarify the contributions of several mutational processes, such as substitutions or homologous recombination. Simplistic, tractable protein models, which determine the compact native structure phenotype from the sequence genotype, are well-suited to such studies. In this paper, we use a lattice-protein model to examine the effects of point mutation and homologous recombination on evolving populations of proteins. We find that while the majority of mutation and recombination events are neutral or deleterious, recombination is far more likely to be beneficial. This results in a faster increase in fitness during evolution, although the final fitness level is not significantly changed. This transient advantage provides an evolutionary advantage to subpopulations that undergo recombination, allowing fixation of recombination to occur in the population. PMID:25473139

Financing biotechnology projects: lender due diligence requirements and the role of independent technical consultants.

PubMed

Keller, J B; Plath, P B

1999-01-01

An increasing number of biotechnology projects are being brought to commercialization using conventional structured finance sources, which have traditionally only been available to proven technologies and primary industries. Attracting and securing competitive cost financing from mainstream lenders, however, will require the sponsor of a new technology or process to undergo a greater level of due diligence. The specific areas and intensity of investigation, which are typically required by lenders in order to secure long-term financing for biotechnology-based manufacturing systems, is reviewed. The processes for evaluating the adequacy of prior laboratory testing and pilot plant demonstrations is discussed. Particular emphasis is given to scale-up considerations and the ability of the proposed facility design to accommodate significant modifications, in the event that scale-up problems are encountered.

Selective Advantage of Recombination in Evolving Protein Populations:. a Lattice Model Study

NASA Astrophysics Data System (ADS)

Williams, Paul D.; Pollock, David D.; Goldstein, Richard A.

Recent research has attempted to clarify the contributions of several mutational processes, such as substitutions or homologous recombination. Simplistic, tractable protein models, which determine the compact native structure phenotype from the sequence genotype, are well-suited to such studies. In this paper, we use a lattice-protein model to examine the effects of point mutation and homologous recombination on evolving populations of proteins. We find that while the majority of mutation and recombination events are neutral or deleterious, recombination is far more likely to be beneficial. This results in a faster increase in fitness during evolution, although the final fitness level is not significantly changed. This transient advantage provides an evolutionary advantage to subpopulations that undergo recombination, allowing fixation of recombination to occur in the population.

Order-disorder phase transition in the peroxidovanadium complex NH4[VO(O2)2(NH3)].

PubMed

Schwendt, Peter; Gyepes, Róbert; Chrappová, Jana; Němec, Ivan; Vaněk, Přemysl

2018-07-05

Complex NH 4 [VO(O 2 ) 2 (NH 3 )] (1) undergoes an order-disorder phase transition at T c ~258K. This transition is accompanied by change in the space group of the orthorhombic lattice and also by significant structural rearrangements of the constituent molecules, which are pertinent mostly to their NH 4 + ions and their ammonia ligands. The low-temperature solid state IR and Raman spectra of 1 were corroborated by solid-state computations that employed Gaussian functions as the basis set. Results of these computations yielded excellent agreement with experimental data. On the curves of temperature dependence of vibrational modes, the phase transition is expressed by an abrupt change of the slope above T c . Copyright © 2018 Elsevier B.V. All rights reserved.

Giant planet migration during FU Orionis outbursts: 1D disc models

NASA Astrophysics Data System (ADS)

Dunhill, A. C.

2018-05-01

I present the results of semi-analytic calculations of migrating planets in young, outbursting circumstellar discs. Formed far out in the disc via gravitational fragmentation early on in its lifetime, these planets typically migrate at very slow rates and are therefore mostly expected to remain at large radii (such as is the case in HR 8799). I show that changes in the disc structure during FUor outbursts affect the planet's ability to maintain a gap and can allow a massive giant planet's semimajor axis to reduce by almost 5 per cent in a single outburst under the most optimistic conditions. Given that a single disc will likely undergo ˜10 such outbursts this process can significantly alter the expected radial distribution for GI-formed planets.

Electron irradiation effects on partially fluorinated polymer films: Structure-property relationships

NASA Astrophysics Data System (ADS)

Nasef, Mohamed Mahmoud; Dahlan, Khairul Zaman M.

2003-04-01

The effects of electron beam irradiation on two partially fluorinated polymer films i.e. poly(vinylidene fluoride) (PVDF) and poly(ethylene-tetrafluoroethylene) copolymer (ETFE) are studied at doses ranging from 100 to 1200 kGy in air at room temperature. Chemical structure, thermal and mechanical properties of irradiated films are investigated. FTIR show that both PVDF and ETFE films undergo similar changes in their chemical structures including the formation of carbonyl groups and double bonding. The changes in melting and crystallisation temperatures ( Tm and Tc) in both irradiated films are functions of irradiation dose and reflect the disorder in the chemical structure caused by the competition between crosslinking and chain scission. The heat of melting (Δ Hm) and the degree of crystallinity ( Xc) of PVDF films show no significant changes with the dose increase, whereas those of ETFE films are reduced rapidly after the first 100 kGy. The tensile strength of PVDF films is improved by irradiation compared to its rapid deterioration in ETFE films, which stemmed from the degradation prompted by the presence of radiation sensitive tetrafluoroethylene (TFE) comonomer units. The elongation at break of both films drops gradually with the dose increase indicating the formation of predominant crosslinked structures at high doses. However, the response of each polymer to crosslinking and main chain scission at various irradiation doses varies from PVDF to ETFE films.

Mechanism of endonuclease cleavage by the HigB toxin

PubMed Central

Schureck, Marc A.; Repack, Adrienne; Miles, Stacey J.; Marquez, Jhomar; Dunham, Christine M.

2016-01-01

Bacteria encode multiple type II toxin–antitoxin modules that cleave ribosome-bound mRNAs in response to stress. All ribosome-dependent toxin family members structurally characterized to date adopt similar microbial RNase architectures despite possessing low sequence identities. Therefore, determining which residues are catalytically important in this specialized RNase family has been a challenge in the field. Structural studies of RelE and YoeB toxins bound to the ribosome provided significant insights but biochemical experiments with RelE were required to clearly demonstrate which residues are critical for acid-base catalysis of mRNA cleavage. Here, we solved an X-ray crystal structure of the wild-type, ribosome-dependent toxin HigB bound to the ribosome revealing potential catalytic residues proximal to the mRNA substrate. Using cell-based and biochemical assays, we further determined that HigB residues His54, Asp90, Tyr91 and His92 are critical for activity in vivo, while HigB H54A and Y91A variants have the largest effect on mRNA cleavage in vitro. Comparison of X-ray crystal structures of two catalytically inactive HigB variants with 70S-HigB bound structures reveal that HigB active site residues undergo conformational rearrangements likely required for recognition of its mRNA substrate. These data support the emerging concept that ribosome-dependent toxins have diverse modes of mRNA recognition. PMID:27378776

Solution Structure of a Phytocystatin from Ananas comosus and Its Molecular Interaction with Papain

PubMed Central

Irene, Deli; Chung, Tse-Yu; Chen, Bo-Jiun; Liu, Ting-Hang; Li, Feng-Yin; Tzen, Jason T. C.; Wang, Cheng-I; Chyan, Chia-Lin

2012-01-01

The structure of a recombinant pineapple cystatin (AcCYS) was determined by NMR with the RMSD of backbone and heavy atoms of twenty lowest energy structures of 0.56 and 1.11 Å, respectively. It reveals an unstructured N-terminal extension and a compact inhibitory domain comprising a four-stranded antiparallel β-sheet wrapped around a central α-helix. The three structural motifs (G45, Q89XVXG, and W120) putatively responsible for the interaction with papain-like proteases are located in one side of AcCYS. Significant chemical shift perturbations in two loop regions, residues 45 to 48 (GIYD) and residues 89 to 91 (QVV), of AcCYS strongly suggest their involvement in the binding to papain, consistent with studies on other members of the cystatin family. However, the highly conserved W120 appears not to be involved in the binding with papain as no chemical shift perturbation was observed. Chemical shift index analysis further indicates that the length of the α-helix is shortened upon association with papain. Collectively, our data suggest that AcCYS undergoes local secondary structural rearrangements when papain is brought into close contact. A molecular model of AcCYS/papain complex is proposed to illustrate the interaction between AcCYS and papain, indicating a complete blockade of the catalytic triad by AcCYS. PMID:23139757

The development and plasticity of alveolar type 1 cells

PubMed Central

Yang, Jun; Hernandez, Belinda J.; Martinez Alanis, Denise; Narvaez del Pilar, Odemaris; Vila-Ellis, Lisandra; Akiyama, Haruhiko; Evans, Scott E.; Ostrin, Edwin J.; Chen, Jichao

2016-01-01

Alveolar type 1 (AT1) cells cover >95% of the gas exchange surface and are extremely thin to facilitate passive gas diffusion. The development of these highly specialized cells and its coordination with the formation of the honeycomb-like alveolar structure are poorly understood. Using new marker-based stereology and single-cell imaging methods, we show that AT1 cells in the mouse lung form expansive thin cellular extensions via a non-proliferative two-step process while retaining cellular plasticity. In the flattening step, AT1 cells undergo molecular specification and remodel cell junctions while remaining connected to their epithelial neighbors. In the folding step, AT1 cells increase in size by more than 10-fold and undergo cellular morphogenesis that matches capillary and secondary septa formation, resulting in a single AT1 cell spanning multiple alveoli. Furthermore, AT1 cells are an unexpected source of VEGFA and their normal development is required for alveolar angiogenesis. Notably, a majority of AT1 cells proliferate upon ectopic SOX2 expression and undergo stage-dependent cell fate reprogramming. These results provide evidence that AT1 cells have both structural and signaling roles in alveolar maturation and can exit their terminally differentiated non-proliferative state. Our findings suggest that AT1 cells might be a new target in the pathogenesis and treatment of lung diseases associated with premature birth. PMID:26586225