bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gone with the Wnts: β-Catenin, T-Cell Factor, Forkhead Box O, and Oxidative Stress in Age-Dependent Diseases of Bone, Lipid, and Glucose Metabolism
Authors: Manolagas Stavros C. , Almeida Maria 
Published: July 2007

Abstract
The Wnt/β-catenin signaling pathway affects several biological processes ranging from embryonic development, patterning, and postembryonic stem cell fate, to bone formation and insulin secretion in adulthood. β-Catenin mediates canonical Wnt signaling by binding to and activating members of the T-cell factor (TCF) transcription factor family. Similar to the Wnt/β-catenin pathway, oxidative stress influences fundamental cellular processes including stem cell fate and has been linked to aging and the development of age-related diseases. However, the molecular details of the pathogenetic effects of oxidative stress on the homeostasis of many different tissues remain unclear. β-Catenin has been recently implicated as a pivotal molecule in defense against oxidative stress by serving as a cofactor of the forkhead box O (FOXO) transcription factors. In addition, it has been shown that oxidative stress is a pivotal pathogenetic factor of age-related bone loss and strength in mice, leading to, among other changes, a decrease in osteoblast number and bone formation. These particular cellular changes evidently result from diversion of the limited pool of β-catenin from TCF- to FOXO-mediated transcription in osteoblastic cells. Fascinatingly, attenuation of Wnt-mediated transcription, resulting from an autosomal-dominant missense mutation in LRP6, a coreceptor for the Wnt-signaling pathway, has been linked recently genetically not only to premature osteoporosis, but also to coronary artery disease as well as several features of the metabolic syndrome including hyperlipidemia, hypertension, and diabetes, but not obesity. In this minireview, we highlight evidence linking the age-associated oxidative stress with FOXOs, Wnt/β-catenin signaling, osteoblastogenesis, adipogenesis, osteoporosis, and several features of the metabolic syndrome. We hypothesize that antagonism of Wnt signaling by oxidative stress with increasing age may be a common molecular mechanism contributing to the development not only of involutional osteoporosis, but several pathologies such as atherosclerosis, insulin resistance, and hyperlipidemia, all of which become more prevalent with advancing age.
Let’s Play with Valence Isomers: The Influence of Different Main Group Elements on Their Relative Stability
Authors: Soleilhavoup Michele , Bertrand Guy 
Published: July 2007

Abstract
Valence isomers are compounds featuring the same fragments connected in different ways. In this personal account, we describe how we first met by serendipity this kind of isomerism, and how later on we used the specific properties of phosphorus and boron to prepare two types of valence isomers that are not accessible with elements exclusively from the first long row. In the carbon series, benzene is calculated to be 608 kJ mol−1 lower in energy than its singlet diradical valence isomer, the anti-tricyclohexylene, but a tetraphosphorus analogue of the latter has been isolated. According to calculations, the parent amidinium salt is 541 kJ mol−1 more stable than its three-membered heterocyclic valence isomer, but in the phosphorus series, the difference in energy between the open and closed forms is only a few kJ mol−1; provided the right substituents are used, the cyclic form can be isolated. Lastly, among butadiene valence isomers, singlet cyclobutane-1,3-diyls were predicted only as transition states for the inversion of bicyclo[1.1.0]butane. In marked contrast, 1,3-dibora-2,4-diphosphacyclobutane-1,3-diyls can be prepared by valence isomerization of the corresponding butadiene derivatives and isolated under conventional experimental conditions.
Development of New Methods to Introduce Unnatural Functional Molecules into Native Proteins for Protein Engineering
Authors: Nakata Eiji , Tsukiji Shinya , Hamachi Itaru 
Published: July 2007

Abstract
Proteins are one of the most sophisticated biomolecules that play important roles in many biological processes and recently have attracted much attention as a key molecular player in new fields of nanobio-science and -technology. To use protein molecules, suitable molecular interfaces for maintaining, regulating, and/or expanding the structure and activity of natural proteins are highly desirable. In addition, development of flexible strategies and new concepts to manipulate protein structures at precise atomic levels is an important challenge from the viewpoint of organic chemistry. In this account, we highlight two unique chemistry-based strategies, developed by our group, for incorporating unnatural molecules into natural proteins, which include (i) reconstitution of chemically modified cofactors with apo-proteins or -enzymes, and (ii) post-(photo)affinity labeling modification of natural proteins. Using these methods, various unnatural molecules were incorporated into natural proteins without any genetic manipulation to produce semi-artificial proteins, of which the function can be regulated, modulated, and/or read-out with help of the incorporated unnatural functionalities.
Dual Fluorescence in a Schiff Base Derived from an Acridinedione Dye. Excited State Intramolecular Proton Transfer
Authors: Thiagarajan Viruthachalam , Ramamurthy Perumal 
Published: July 2007

Abstract
Newly synthesized nonconjugated, but covalently linked, bichromophoric systems (ADDSA) contain a salicylideneaniline (SA) moiety linked to an acridinedione (ADD) fluorophore via a covalent bond. The absorption and fluorescence characteristics of the ADDSA systems in various solvents reveal that the dual fluorescence originates from two different chromophores in the same molecule. The solvent polarity independent, long wavelength anomalous emission originates from the keto form of SA moiety via excited state intramolecular proton transfer (ESIPT). The ESIPT pathway was further confirmed by the benzylideneaniline (BA) and ADD moieties coupled non-proton transfer model system (ADDBA). Absence of the longer wavelength anomalous emission in the steady state as well as the shorter lifetime component in the time-resolved study for ADDBA system supports ESIPT mechanism for long wavelength anomalous emission in ADDSA system.
Dichroic Measurements on Dicationic and Tetracationic Porphyrins on Clay Surfaces with Visible-Light-Attenuated Total Reflectance
Authors: Eguchi Miharu , Tachibana Hiroshi , Takagi Shinsuke , Tryk Donald A , Inoue Haruo 
Published: July 2007

Abstract
Complexes formed with synthetic clay minerals and dicationic and tetracationic porphyrins were prepared. The Soret bands of the multicationic porphyrins shifted to longer wavelength upon the formation of a complex with clay. The clay sheets themselves and the porphyrin molecules on the clay surface were examined by use of atomic force microscopy (AFM) and polarized visible-light-attenuated total reflectance (ATR) spectroscopy (PV-ATR) with a waveguide system. The flat adsorption of the clay sheets on the glass substrates was confirmed by AFM. A theoretical treatment of the analysis by ATR spectroscopy was derived. The orientations of the multicationic porphyrin molecules on the clay sheets in water turned out to be nearly parallel (&lt;5°) to the clay surface, based on the PV-ATR analysis.
Synthesis and Crystal Structures of Fluorinated Chromophores for Second-Order Nonlinear Optics
Authors: Umezawa Hirohito , Okada Shuji , Oikawa Hidetoshi , Matsuda Hiro , Nakanishi Hachiro 
Published: July 2007

Abstract
Partially fluorinated skeleton of 4-[2-(4-dimethylamino-2,3,5,6-tetrafluorophenyl)ethynyl]-2,3,5,6-tetrafluoro-N,N,N-trimethylanilinium (2) was synthesized as a second-order nonlinear optical (NLO) material to decrease the absorption around 1.3 and 1.5 μm, which deteriorates the device efficiency. Several salts of 2 were prepared, and we found that the trifluoromethanesulfonate salt of 2 (2b) had a shorter absorption-maximum wavelength compared to that of 4-nitroaniline (pNA). From hyper-Rayleigh scattering (HRS) measurement, the β value of 2b was found to be about 8 times greater than that of pNA. We also performed X-ray crystallographic analysis of 2b and estimated NLO coefficient (d) by the oriented gas model. We found that diagonal component of 2b (d11=610 pm V−1) was about 14 times greater than that of 2-methyl-4-nitroaniline and off-diagonal component of 2b (d12=155 pm V−1) was about 6.5 times greater than that of N-(4-nitrophenyl)-l-prolinol. Compound 2b should be an excellent candidate for NLO applications.
Preparation of Acid-Functionalized Poly(phenylene oxide)s and Poly(phenylene sulfone) and Their Proton Conductivity
Authors: Tago Takahiro , Kuwashiro Norikazu , Nishide Hiroyuki 
Published: July 2007

Abstract
A series of highly acid-functionalized poly(phenylene oxide)s and poly(phenylene sulfone) were prepared and proton conductivity in their membranes is discussed. Phosphorylated poly(phenylene oxide)s were prepared via the oxidative polymerization of phosphonoxyphenols in alkaline water, along with a facile monomer preparation. A poly(phenylene oxide) bearing a sulfamide acid group was prepared by reacting amidosulfate with the corresponding carboxylated poly(phenylene oxide). A sulfonated poly(phenylene sulfone) was prepared by hydrogen peroxide oxidation of the sulfonated poly(phenylene sulfide). All these acid-functionalized polymers showed appropriate thermal stability based on the aromatic backbone. The polymers had a high ion-exchange capacity, were water-soluble, but gave transparent and flexible membranes after compositing with the poly(ethylene oxide). Some of the membranes displayed a high proton conductivity of 10−4 S cm−1 at 120 °C under dry conditions.
Trends in abnormal cancer screening results in the United States of America
Authors: Yabroff K Robin , Freedman Andrew , Brown Martin L , Ballard-Barbash Rachel , McNeel Timothy , Taplin Stephen 
Published: July 2007

Background: Although recent trends in the use of recommended breast and cervical cancer screening have been well documented in the USA, little is known about trends in the prevalence of abnormal screening results. Methods: Trends in abnormal screening results for mammography and Papanicolaou (Pap) smear were assessed descriptively using data from the 1987 and 2000 National Health Interview Surveys. Estimates were stratified by sociodemographic characteristics of the populations who reported ever receiving screening. All comparisons were evaluated with two-sided tests of statistical significance. Results: The age-standardized prevalence of abnormal Pap smears increased from 12.9% (95% confidence interval [CI] 12.1–13.8%) of women ever screened in 1987 to 20.3% (95% CI 19.5–21.0%) in 2000, and the age-standardized prevalence of abnormal mammogram results increased from 18.8% (95% CI 17.0–20.7%) to 21.6% (95% CI 20.5–22.7%) of women ever screened over the same period. Among women aged 40 years and older who reported ever receiving both a Pap smear and a mammogram, 29.6% (95% CI: 27.3–32.2%) in 1987 and 35% (95% CI: 33.8–36.2%) in 2000 reported either an abnormal Pap smear or an abnormal mammogram. In 2000, abnormal screening results were positively associated with reported frequency of recent screening ( P<0.001). Conclusions: A substantial portion of women in the USA reporting cancer screening also report having had abnormal results, although the magnitude of trends between 1987 and 2000 vary by screening test. Additional research is needed to assess the relative contributions of changes in classification of test results, test characteristics and changes in underlying screening histories to increases in abnormal screening results.
Prevalence of neural tube defect pregnancies in England and Wales from 1964 to 2004
Authors: Morris J K , Wald N J 
Published: July 2007

Objectives: To determine the prevalence of pregnancies with a neural tube defect (NTD) in England and Wales between 1964 and 2004 and to estimate the relative impact of antenatal screening and a change in the incidence of these defects on the prevalence of births with NTDs. Settings: Use of data published by the Office for National Statistics (ONS) on terminations of pregnancies with an NTD and births with an NTD from 1964 to 2004. Methods: Estimates were made of the total number of terminations of pregnancies and births with an NTD by taking account of the under-reporting of these terminations and births using a previously described method. In 1995 ONS started to report the number of terminations with an NTD rather than the total numbers of terminations with a central nervous system (CNS) malformation that had previously been used to estimate the number of NTD terminations. Adjustment was made for this and new estimates of the total number of NTD pregnancies were produced to 2004. Results: There were an estimated 969 pregnancies with NTDs (168 (17%) births and 801(83%) terminations) in England and Wales in 2004. An estimated 44% of NTD terminations and 32% of births were not reported as such. The birth prevalence per 1000 decreased fallen 93% from 3.6 in 1964 to 0.3 in 2004, 59% due to an underlying decrease in the prevalence of NTDs and 34% due to screening diagnosis and subsequent termination of affected pregnancies. Conclusion: The prevalence of NTD pregnancies decreased by around two per 1000 from 1964 to 1990 and thereafter remained fairly constant. The prevalence of NTD pregnancies is substantially underestimated if it is based only on reported NTD births (by 88%) and also if it is based on reported NTD births and terminations (by 52%), because most NTD pregnancies in England and Wales are terminated following antenatal screening and most of these terminations are not reported.
Vertical distribution of spores of blade-forming Sarcothalia crispata (Gigartinaceae) and crustose corallines (Corallinaceae) in the water column
Authors: Opazo L. Felipe , Otaíza Ricardo D. 
Published: July 2007

Abstract
Changes in spore abundance of the blade-forming Sarcothalia crispata and crustose coralline seaweeds were determined to relate height above the substratum at which propagules are liberated with their dispersal potential. Recruit density was quantified on artificial substrata at the surface of the water column, mid-water, and seafloor. Spore abundance was determined in water samples obtained at the same levels during periods of calm and rough seas. Spore density was also determined along a transect running perpendicularly to the shore. Density of recruits S. crispata increased with depth, whereas coralline recruits were abundant at the seafloor level. During calm seas, spore density of S. crispata and crustose corallines increased with depth, but the latter were more variable. During rough seas, spore density was very high; spores of S. crispata increased toward the surface, or were homogenous in the water column, whereas distribution of crustose coralline spores was more variable. Finally, density of crustose coralline spores decreased more abruptly with distance from the shore than that of the bladed species. These results strongly suggest that the height at which spores are released (a correlate of algal morphology) influences spore distribution in the water column and the dispersal potential.
Nitrate reductase in the marine macroalga Kappaphycus alvarezii (Rhodophyta): oscillation due to the protein level
Authors: Granbom Malena , Lopes Patrícia F. , Pedersén Marianne , Colepicolo Pio 
Published: July 2007

Abstract
Nitrate reductase (NR; EC 1.6.6.1) of the marine red macroalga Kappaphycus alvarezii was examined in algae maintained under L:D and constant light conditions. Undenaturated protein had a molecular mass of about 210 kD (±23 kD); based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting techniques, the enzyme appears to be composed of two possibly identical subunits of 100 kD. The NR of K. alvarezii was recognized by 10 out of 17 monoclonal antibodies raised against the NR from the red alga Porphyra yezoensis. Basal parts of the algal thallus had higher NR protein content, although the highest activity of NR has been located previously in the apical thallus parts, suggesting a post-translational regulation. The cellular expression of NR exhibits a daily rhythm. In extracts of algae grown under either constant light or a light:dark cycle, staining with antibodies NR 6 and NR 10 showed that the amount of protein varied by a factor of about 2, with the maximum occurring in the early day phase.
The impact of process stress on suspended anchorage‐dependent mammalian cells as an indicator of likely challenges for regenerative medicines
Authors: Zoro B.J.H. , Owen S. , Drake R.A.L. , Hoare M. 
Published: July 2007

AbstractTo quantify the engineering shear constraint on processing, the effect of capillary shear stress (pipe flow) on suspended anchorage‐dependent mammalian cells has been investigated. Exposure of cultured rat aortic smooth muscle cells to repeated capillary shear stress (2–120 N m−2) causes a decrease in total number of cells, number of intact cells and number of cells able to grow. The optimum wall shear stress for cell survival was found to be 10–50 N m−2 (flowrate 4–20 mL/min, I.D. 0.45 mm). Cell populations which are able to grow after exposure to shear stress do not exhibit reduced growth rate or altered metabolism. Biotechnol. Bioeng. 2008;99: 468–474. © 2007 Wiley Periodicals, Inc.
Ground state energy scaling laws during the onset and destruction of the intermediate state in a type I superconductor
Authors: Choksi Rustum , Conti Sergio , Kohn Robert V. , Otto Felix 
Published: July 2007

AbstractThe intermediate state of a type I superconductor is a classical example of energy‐driven pattern formation, first studied by Landau in 1937. Three of us recently derived five different rigorous upper bounds for the ground‐state energy, corresponding to different microstructural patterns, but only one of them was complemented by a lower bound with the same scaling [Choksi, Kohn, and Otto, J. Nonlinear Sci. 14 (2004), 119–171]. This paper completes the picture by providing matching lower bounds for the remaining four regimes, thereby proving that exactly those five different regimes are traversed with an increasing magnetic field. © 2007 Wiley Periodicals, Inc.
A Note on Second Harmonics Generated by a Surface Wave on a Warm Plasma Half‐Space
Authors: Ghosh B. , Das K. P. 
Published: July 2007

AbstractA part of the second harmonics generated through the self‐interaction of a surface wave on a warm plasma half‐space is shown not to have a surface wave character but represents a wave propagating obliquely away from the plasma‐vacuum interface into the bulk of the plasma.
Increased Power Concentration and its Effect on the Discharge Parameters of the Low Pressure Hg‐rare Gas Positive Column I. Variation of Current
Authors: Kreher J. , Stern W. 
Published: July 2007

AbstractBy measuring the radiant flux of the resonance lines of mercury, the field strength and the electron energy distribution function the influence of the current on the parameters, especially on the energy balance of the Hg—Ar positive column is investigated, compared with a kinetic model, and interpreted. The decrease in yield of the 254 nm radiation with increasing current is linked to a corresponding increase of the losses due to elastic collisions with the rare gas atoms and is caused by the changes in the electron energy distribution function. Moreover, the influence of gas temperature, Hg‐densities and effective life times is investigated.
Plasma Properties and Neutral Gas Densities in Hg‐Rare Gas Discharges
Authors: Kreher J. , Stern W. 
Published: July 2007

AbstractThe density of the neutral gases in Hg‐rare gas discharges and their spatial distribution is controlled by the discharge parameters as well as by the externally adjustable partial pressures. Essential quantities in this context are the gas temperature produced by elastic collisions, the ion transport by the discharge current, the processes governing the wall temperature, and ambipolar diffusion. Despite equal partial pressures different densities may occur, which, in turn, will influence the parameters of the discharge. This has effects on the assessment of the methods of Hgvapour pressure adjustment and on the evaluation of the measured values. These effects are demonstrated, especially by field strength measurements, for a wide parameter range.
Ignition Processes in ac Plasma Displays
Authors: Röpcke J. , Zahn R.‐J. 
Published: July 2007

AbstractThe ignition behaviour of discharge cells in ac plasma displays, their ignition statistics and interaction processes occurring between several ignited cells are described and interpreted with a view to basic problems of gas discharge and solid state physics. Ac plasma displays of three different sizes were investigated: PAF 58, 90 and PAF 128.
2 D Tokamak Edge Simulation Including Impurities
Authors: Krech M. , Neuhauser J. , Schneider W. 
Published: July 2007

AbstractIn the first part of this paper we present multifluid model calculations of marfe instabilities in a simple geometry. Assuming carbon as the dominant impurity, the time evolution of the 2D Marfe is followed and typical e‐folding times and their variation with the poloidal and radial heat conductivities are determined. In part two of this paper we present a scrape‐off layer simulation in a typical x‐point geometry using a simplyfied hydrogen recycling model and again carbon as impurities. Other impurity species can be treated as well.
ASDEX Edge and Divertor Simulation and the Problem of Incomplete and Inaccurate Experimental Data
Authors: Schneider W. , Neuhauser J. , Haas G. , McCormick K. , Tsois N. , Wunderlich R. 
Published: July 2007

AbstractThe one‐dimensional hydrodynamic code SOLID coupled with the two‐dimensional Monte Carlo neutral gas code DEGAS are used to simulate the scrape‐off layer and divertor recycling region of the ASDEX tokamak. A numerical data base is created for the relevant parameter regime and compared to the limited amount of experimental data. A reasonable fit with ohmic data is obtained, assuming classical heat flow along field lines and allowing for varying divertor saturation. The problem of experimental errors on one side and deficiencies in the theoretical model on the other side are discussed.
Modelling of the 2‐Dimensional Structure and Impurity Transport for a Scrape‐Off Layer with a Solid Limiter
Authors: Kawamura T. , Ono T. , Masuda Y. , Reiter D. 
Published: July 2007

AbstractFirst the 2‐dimensional modelling of a scrape‐off layer with a solid limiter is performed. After the plasma in a scrape‐off layer is calculated by a plasma code SLIM based on the 2‐dimensional fluid equations with source terms due to neutral particles, the neutral transport is calculated by a Monte Carlo code EIRENE with the use of the results by SLIM and these two calculations are iteratively performed until a nearly self‐consistent result is obtained. Next, in the scrape‐off plasma thus obtained, ionization of neutral impurity particles ejected from the first wall and random diffusion of the charged impurities across the magnetic field lines are simulated by a Monte Carlo method. From the statistical analysis on the numerical results the screening efficiency of a scrape‐off layer, impurity redeposition rate and behaviour of impurities in a scrape‐off layer are analyzed.
Temperature Determination from the Continuous Emission of a Dense Argon Plasma
Authors: Szymanski Z. 
Published: July 2007

AbstractThe temperature of the laser sustained plasma has been determined from the continuum emission coefficient at different wavelengths. The experiments were performed in an argon plasma at the pressure of 10 atm. The spurious continuum resulting from merging of spectral lines was investigated numerically. Its influence on the measured emission coefficient in the red region has been found to be considerable.