bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical study of soil heterogeneity effects on contaminant transport in unsaturated soil (model development and validation)
Authors: Mousavi Nezhad M. , Javadi A. A. , Al‐Tabbaa A. , Abbasi F.
Published: October 2011

The movement of chemicals through soil to groundwater is a major cause of degradation of water resources. In many cases, serious human and stock health implications are associated with this form of pollution. The study of the effects of different factors involved in transport phenomena can provide valuable information to find the best remediation approaches. Numerical models are increasingly being used for predicting or analyzing solute transport processes in soils and groundwater. This article presents the development of a stochastic finite element model for the simulation of contaminant transport through soils with the main focus being on the incorporation of the effects of soil heterogeneity in the model. The governing equations of contaminant transport are presented. The mathematical framework and the numerical implementation of the model are described. The comparison of the results obtained from the developed stochastic model with those obtained from a deterministic method and some experimental results shows that the stochastic model is capable of predicting the transport of solutes in unsaturated soil with higher accuracy than deterministic one. The importance of the consideration of the effects of soil heterogeneity on contaminant fate is highlighted through a sensitivity analysis regarding the variance of saturated hydraulic conductivity as an index of soil heterogeneity. Copyright © 2011 John Wiley & Sons, Ltd.
Multiscale method for long tunnels subjected to seismic loading
Authors: Yu Hai‐Tao , Yuan Yong , Bobet Antonio
Published: October 2011

A multiscale method for the dynamic analysis of underground structures is proposed, which involves the concurrent discretization of the entire domain with both coarse‐scale and fine‐scale finite element meshes. The coarse‐scale mesh is employed to capture seismic response characteristics of the integral system, whereas the fine‐scale mesh describes in detail the dynamic response in positions of potential damage or interest. For both the coarse‐scale and fine‐scale meshes to overlap, a bridging scale term is introduced so that compatibility of dynamic behavior between the coarse‐ and fine‐scale models is enforced. Both material and contact nonlinearities are considered in the multiscale model. As an application, the model is used for large‐scale seismic response of a newly built long‐distance shield tunnel. Results show that this multiscale method does not have spurious wave reflections at the fine/coarse interface and does not need filtering procedures, which is an advantage compared with the displacement coupling method. Stress and deformation response in lining segments and their connecting bolts are investigated and analyzed within the fine‐scale model, and the capacity of critical structural components, such as bolts and joints is evaluated. Copyright © 2011 John Wiley & Sons, Ltd.
Influence of Mo back contact porosity on co‐evaporated Cu(In,Ga)Se2 thin film properties and related solar cell
Authors: Bommersbach P. , Arzel L. , Tomassini M. , Gautron E. , Leyder C. , Urien M. , Dupuy D. , Barreau N.
Published: October 2011

The present study aims at investigating the influence of Ar sputtering gas pressure on the properties of molybdenum back contact (deposited on soda‐lime glass) and consequences on co‐evaporated Cu(In,Ga)Se2 (CIGSe) absorber layer and related solar cell. Films 300 nm thick have been grown with argon pressure between 0·75 and 11·25 mTorr; these films have been characterized by several techniques showing that the increase of the sputtering pressure yields wider amorphous areas, containing oxygen and sodium, between the molybdenum grains, thus higher sheet resistance. The volume ratio of these amorphous areas is referenced to as “porosity”. The structural and morphological properties of co‐evaporated CIGSe have not been reliably observed influenced by the molybdenum porosity; the only noticeable change is the sodium content of the absorber, which increases with the porosity of the back contact. The impact of the amount of sodium on the device performance has been observed to be very important. On the one hand, as already reported, sodium is beneficial for the open‐circuit voltage. On the other hand, a too high amount of sodium is detrimental for the fill factor (hindered shunt resistance), thus the cell efficiency; this latter observation is interpreted as a change in the grain boundary electrical properties. Copyright © 2011 John Wiley & Sons, Ltd.
Competitive interaction between halogen and hydrogen bonds in NH2Br‐HOX (X = F, Cl, and Br) complex
Authors: Li Qingzhong , Li Hui , Gong Jianhui , Li Wenzuo , Cheng Jianbo
Published: October 2011

The NH2Br‐HOX (X = F, Cl, and Br) complexes have been investigated with quantum chemical calculations at the MP2/aug‐cc‐pVTZ level. Five isomers are observed for the Cl and Br complexes, whereas only two isomers are found for the F complex. The geometrical, energetic, and spectroscopic parameters have been analyzed for these complexes. The hydrogen‐bonded complexes are more stable than the halogen‐bonded ones. In most complexes, the associated OH and OX bonds are elongated and show a red shift, whereas the distant bonds are contracted and exhibit a blue shift. The complexes have been analyzed with natural bond orbital and atoms in molecules. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012
Dynamic changing features of the molecular face for interaction of a rare gas atom with a hydrogen molecule
Authors: Ding Yan‐Li , Li En‐Bo , Gong Li‐Dong
Published: October 2011

We perform a systematical investigation on the dynamic changing feature of the molecular shape and size and electron density distribution in the process of a rare‐gas atom (He, Ne, Ar, and Kr) approaching a hydrogen molecule by an ab initio method. In terms of the molecular face (MF) theory, the polarization effect in the above processes is vividly demonstrated. There is a good linear correlation between our average variation rate (Saver) of molecular intrinsic characteristic radius at the contacting point and the experimental polarizability of the rare‐gas atoms. This indicates that the MF theory can well represent the intermolecular polarization effect. Interestingly, the pictures of shape changing, charge‐flow, and exchange repulsion processes especially on the reacting active areas have been clearly observed. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Stoichiometric vanadium oxides studied by XPS
Authors: Hryha E. , Rutqvist E. , Nyborg L.
Published: October 2011

Recovery of vanadium oxide from steelmaking slag is of great interest for Swedish steel producers and the technique for assessing the oxidation state of vanadium is crucial in the optimization of vanadium recovery. There is a large spread in the reported values of published V2p3/2 binding energy values for various oxidation states of vanadium. Therefore, an extensive analysis of vanadium oxide standards was performed aimed at obtaining reliable data and improved methods for the preparation of representative oxide standards. Powdered oxide standards of V2O5, VO2, V2O3, and VO, with purity better than 99%, were chosen. In their as‐received state, all of the standards are covered by a thin layer of vanadium pentoxide that does not allow accurate evaluation of X‐ray photoelectron spectroscopy spectra for vanadium oxides at lower oxidation states. Therefore, different methods for obtaining a representative surface for vanadium oxide standards were tested. The experimental results show high sensitivity of vanadium oxide standards to argon ion etching. Hence, a method to obtain a representative surface of standards by special heat treatment is proposed. Such approach was developed using a preparation chamber (furnace) attached to an X‐ray photoelectron spectroscopy instrument. The annealing was performed in a vacuum at defined temperatures from 400 to 900 °C for 4–24 h; the annealing parameters were selected based on thermodynamic equilibrium data for vanadium oxides. Experimental fitting parameters (peak position E and full width of half maximum of the peak) for vanadium V2p3/2 and oxygen O1s peaks are thus obtained for stoichiometric vanadium oxides. Copyright © 2011 John Wiley & Sons, Ltd.
Meteorological phenomena in Western classical orchestral music
Authors: Aplin Karen L. , Williams Paul D.
Published: October 2011

Depictions of the weather are common throughout the arts. Unlike in the visual arts, however, there has been little study of meteorological inspiration in music. This article catalogues and analyzes the frequencies with which weather is depicted in a sample of classical orchestral music. The depictions vary from explicit mimicry using traditional and specialized orchestral instruments, through to subtle suggestions. It is found that composers are generally influenced by their own environment in the type of weather they choose to represent. As befits the national stereotype, British composers seem disproportionately keen to depict the UK's variable weather patterns and stormy coastline. Copyright © 2011 Royal Meteorological Society
Bacteriological analysis of bile in acute cholecystitis according to the Tokyo guidelines
Authors: Asai Koji , Watanabe Manabu , Kusachi Shinya , Tanaka Hidenori , Matsukiyo Hiroshi , Osawa Akihiro , Saito Tomoaki , Kodama Hajime , Enomoto Toshiyuki , Nakamura Yoichi , Okamoto Yasushi , Saida Yoshihisa , Nagao Jiro
Published: October 2011

Background

We performed bacteriological analysis of bile in acute cholecystitis (AC) patients graded in severity according to the Tokyo guidelines.

Methods

We enrolled 163 AC patients in whom bacteriological analysis of bile was performed.

Results

Significant differences in age (60 vs. 67 years), body temperature (BT) (37.2 vs. 37.6°C), white blood cell count (13,033 vs. 15,177/mm3), and serum C‐reactive protein (CRP) (8.9 vs. 16.9 mg/dL) were found between the Mild and Moderate severity groups. The prevalence of bactibilia differed significantly between Mild and Moderate patients (45.3 vs. 67.0%, P = 0.0107); however, there were no significant differences in the bacterial strains, prevalence of antimicrobial resistance, or polymicrobial isolation frequency between the 2 groups. Our local antibiogram revealed that several microorganisms showed higher resistance rates; these were also isolated even in Mild cases. Advanced age, high BT, high serum CRP, and presence of marked local infection were identified as being significantly associated with high risk of bactibilia. Receiver operating characteristic curve analysis indicated the optimal cutoff value of age to be 65 years, of BT to be 37.5°C, and of serum CRP to be 13.4 mg/dL.

Conclusion

Adequate broad‐spectrum antimicrobial therapy should be administered perioperatively even for Mild patients classified according to the current Tokyo guidelines. These results suggest that more precise severity grades may need to be established, including age and CRP as additional parameters.
Mammography: EUSOBI recommendations for women’s information
Authors: Sardanelli Francesco , Helbich Thomas H. ,   for the European Society of Breast Imaging (EUSOBI)
Published: October 2011

This paper summarises the basic information to be offered to women who undergo mammography. After a delineation of the general aim of early diagnosis of breast cancer, the main difference between screening mammography and diagnostic mammography is explained. The best time for scheduling mammography in fertile women is defined. The need to bring images and reports from the previous mammogram (and from other recent breast imaging examinations) is highlighted. The technique and procedure of mammography are briefly described with particular attention to discomfort and pain experienced by a fraction of women who undergo the test. Information is given on the recall during a screening program and on the request for further work-up after a diagnostic mammography. The logic of the diagnostic mammography report and of classification systems such as BI-RADS and R1-R5 is illustrated, and brief but clear information is given about the diagnostic performance of the test, with particular reference to interval cancers. Moreover, the breast cancer risk due to radiation exposure from mammography is compared to the reduction in mortality obtained with the test, and the concept of overdiagnosis is presented. Finally, five frequently asked questions are answered.
Cardiac Rehabilitation After Heart Valve Surgery
Authors: Kiel Martin K.
Published: October 2011

Cardiac rehabilitation (CR) is approved by the Centers for Medicare and Medicaid Services for patients who have had heart valve surgery. Analysis of data shows that CR increases exercise capacity and quality of life, and facilitates return to work, with minimal risk of significant adverse effects. In spite of this, CR is vastly underused. Recommendations to improve this include an automatic referral system, liaison assistance to speak with inpatients about CR, and establishment of CR programs in areas that have poor access to the large hospital‐based facilities. Components of CR for patients who have had heart valve surgery also are discussed in this review.
Emerging Concepts in the Treatment of Myofascial Pain: A Review of Medications, Modalities, and Needle‐based Interventions
Authors: Annaswamy Thiru Mandyam , De Luigi Arthur J. , O'Neill Bryan J. , Keole Nandita , Berbrayer David
Published: October 2011

Significant developments and changes in the use of interventions and treatments for the management of myofascial pain syndrome have occurred in the past 10 years. These emerging concepts have changed the approach for clinicians who manage these pain disorders. However, wide variations in practice patterns prevail, and no clear consensus exists regarding when and how to use these interventions; in addition, awareness of the evidence basis behind their use is limited. This review examines the most recent advances in the treatment of myofascial pain syndromes. Specifically, the evidence basis of various emerging interventions is reviewed and recommendations for routine clinical practice and their rationale are provided. The purpose of this review is to provide the clinician with a better understanding of emerging concepts in the interventions used for myofascial pain syndromes.
The First Modern Economy
Authors: de Vries Jan , van der Woude Ad
Published: October 2011

The First Modern Economy provides a comprehensive economic history of the Netherlands during its rise to European economic leadership, the 'Golden Age', and subsequent decline (1500–1815). The authors argue that it was the first modern economy, and defend their position with detailed analyses of its major economic sectors, as well as investigations of social structure and macro-economic performance. Dutch economic history is placed in its European and world context, and inter-continental and colonial trade are discussed fully. Special emphasis is placed on the environmental context of economic growth and later decline, as well as on demographic developments. The authors also argue that the Dutch model of development and stagnation is applicable to currently maturing economies.
Cost-effectiveness of targeted screening for hepatitis C in The Netherlands
Authors: HELSPER C. W. , BORKENT-RAVEN B. A. , DE WIT N. J. , VAN ESSEN G. A. , BONTEN M. J. M. , HOEPELMAN A. I. M. , JANSSEN M. P. , DE WIT G. A.
Published: October 2011

On account of the serious complications of hepatitis C virus (HCV) infection and the improved treatment possibilities, the need to improve HCV awareness and case-finding is increasingly recognized. To optimize a future national campaign with this objective, three pilot campaigns were executed in three regions in The Netherlands. One campaign was aimed at the general population, a second (similar) campaign was extended with a support programme for primary care and a third campaign was specifically aimed at hard-drug users. Data from the pilot campaigns were used to build a mathematical model to estimate the incremental cost-effectiveness ratio of the different campaigns. The campaign aimed at the general public without support for primary care did not improve case-finding and was therefore not cost-effective. The similar campaign accompanied by additional support for primary care and the campaign aimed at hard-drug users emerged as cost-effective interventions for identification of HCV carriers.
On the computational complexity of dynamic slicing problems for program schemas
Authors: DANICIC SEBASTIAN , HIERONS ROBERT. M. , LAURENCE MICHAEL R.
Published: October 2011

Given a program, a quotient can be obtained from it by deleting zero or more statements. The field of program slicing is concerned with computing a quotient of a program that preserves part of the behaviour of the original program. All program slicing algorithms take account of the structural properties of a program, such as control dependence and data dependence, rather than the semantics of its functions and predicates, and thus work, in effect, with program schemas. The dynamic slicing criterion of Korel and Laski requires only that program behaviour is preserved in cases where the original program follows a particular path, and that the slice/quotient follows this path. In this paper we formalise Korel and Laski's definition of a dynamic slice as applied to linear schemas, and also formulate a less restrictive definition in which the path through the original program need not be preserved by the slice. The less restrictive definition has the benefit of leading to smaller slices. For both definitions, we compute complexity bounds for the problems of establishing whether a given slice of a linear schema is a dynamic slice and whether a linear schema has a non-trivial dynamic slice, and prove that the latter problem is NP-hard in both cases. We also give an example to prove that minimal dynamic slices (whether or not they preserve the original path) need not be unique.
Story of the Delhi Iron Pillar
Authors: Balasubramaniam R.
Published: October 2011

Story of the Delhi Iron Pillar traces the history of the pillar located in the Qutub Complex and describes its structure in detail. It unravels the mystery behind the resistance of the pillar to corrosion for more than sixteen centuries. It also discusses the amazing process by which the pillar was manufactured using the technical know-how available at the time. The book is primarily aimed at general readers and tourists, with a view to igniting their interest in this metallurgical wonder of ancient India. Written in simple language and a lucid style, it carries numerous photographs and elaborate figures to enhance the discussion.
Sustainable Development at Risk
Authors: Hulse Joseph H.
Published: October 2011

Over the past half century, the idea of sustainable development has evolved and rooted itself in the lexicon on international development. But what is it, really? Are development agencies truly committed to long-term sustainable solutions to development issues? Are we learning from our past successes and failures? This book takes an historical perspective on these questions. The analysis begins with the Atlantic Charter, the creation of the United Nations, its family of agencies, and the international development banks. It reviews recommendations from international commissions and conferences, from World bank and UNDP development reports. It comments on governmental policies, human and industrial actions detrimental to the planet's environment and natural resources. It studies the patterns by which biotechnologies essential to human survival and health have progressed over the past 8,000 years, and the consequences of uncontrolled urban growth on food and health security.
English in Deprived Circumstances
Authors: Amritavalli R.
Published: October 2011

Can learners of English choose their own materials to learn from? Should they do so? English in Deprived Circumstances: Maximising Learner Autonomy is a narrative of how learners learn when they take charge of what they read, listen to or write. The author makes a case for learner autonomy from her experiences with fifteen first generation learners, working children attending a non-formal afternoon school, and a group of adult learners from outside India. Key issues discussed:- Autonomy and authenticity in language learning- What is authentic for deprived learners?- Emergent features of learner-chosen texts- Assessment of acquisition- A new approach to the choice of materials
Serine biosynthesis with one carbon catabolism represents a novel pathway for ATP generation in cells using alternative glycolysis with zero net ATP production
Authors: Vazquez Alexei , Markert Elke , Oltvai Zoltan
Published: October 2011

Recent experimental evidence indicates that some cancer cells have an alternative glycolysis pathway with net zero ATP production, implying that upregulation of glycolysis in these cells may not be related to the generation of ATP. Here we use a genome-scale model of human cell metabolism to investigate the potential metabolic alterations in cells using net zero ATP glycolysis. We uncover a novel pathway for ATP generation that involves reactions from the serine biosynthesis and one-carbon metabolism pathways. This pathway has a predicted two-fold higher flux rate in cells using net zero ATP glycolysis than those using standard glycolysis and generates twice as much ATP with significantly lower rate of lactate- but higher rate of alanine secretion. Thus, in cells using the standard- or the net zero ATP glycolysis pathways a significant portion of the glycolysis flux is always associated with ATP generation, and the ratio between the flux rates of the two pathways determines the rate of ATP generation and lactate and alanine secretion during glycolysis.
Homo- and hetero-dimeric architecture of the human liver Na+-dependent taurocholate co-transporting protein
Authors: Bijsmans Ingrid T. G. W. , Bouwmeester Rianne A. M. , Geyer Joachim , Faber Klaas Nico , van de Graaf Stan F. J.
Published: October 2011

The NTCP (Na+–taurocholate co-transporting protein)/SLC10A [solute carrier family 10 (Na+/bile acid co-transporter family)] 1 is tightly controlled to ensure hepatic bile salt uptake while preventing toxic bile salt accumulation. Many transport proteins require oligomerization for their activity and regulation. This is not yet established for bile salt transporters. The present study was conducted to elucidate the oligomeric state of NTCP. Chemical cross-linking revealed the presence of NTCP dimers in rat liver membranes and U2OS cells stably expressing NTCP. Co-immunoprecipitation of tagged NTCP proteins revealed a physical interaction between subunits. The C-terminus of NTCP was not required for subunit interaction, but was essential for exit from the ER (endoplasmic reticulum). NTCP without its C-terminus (NTCP Y307X) retained full-length wtNTCP (wild-type NTCP) in the ER in a dominant fashion, suggesting that dimerization occurs early in the secretory pathway. FRET (fluorescence resonance energy transfer) using fluorescently labelled subunits further demonstrated that dimerization persists at the plasma membrane. NTCP belongs to the SLC10A protein family which consists of seven members. NTCP co-localized in U2OS cells with SLC10A4 and SLC10A6, but not with SLC10A3, SLC10A5 or SLC10A7. SLC10A4 and SLC10A6 co-immunoprecipitated with NTCP, demonstrating that heteromeric complexes can be formed between SLC10A family members in vitro. Expression of SLC10A4 and NTCP Y307X resulted in a reduction of NTCP abundance at the plasma membrane and NTCP-mediated taurocholate uptake, whereas expression of SLC10A6 or NTCP E257N, an inactive mutant, did not affect NTCP function. In conclusion, NTCP adopts a dimeric structure in which individual subunits are functional. Bile salt uptake is influenced by heterodimerization when this impairs NTCP plasma membrane trafficking.
Room temperature magnetometry of an individual iron filled carbon nanotube acting as nanocantilever
Authors: Philippi S. , Weißker U. , Mühl T. , Leonhardt A. , Büchner B.
Published: October 2011

The influence of external magnetic fields on the bending vibration of a one-side clamped iron filled carbon nanotube (CNT) has been analyzed theoretically and experimentally, with particular consideration given to the changes in the resonance frequency. The model involves the application of a modified Euler-Bernoulli-beam to analyze the zero field oscillatory behavior, as well as a magnetostatic approach used to determine the influence of any external field distributions. The experiments were conducted in situ in a scanning electron microscope. The measured magnetic moment of the nanowire at room temperature was μ = 2.1 × 10−14 Am2. Due to the favorable geometry of the CNT oscillator, the raw signal obtained using this approach is significantly more favorable than that with state of the art cantilever magnetometry. The obtained good agreement between model and experiment provides a valuable basis for the development of nanoelectromechanical systems in which magnetic interactions are relevant.
Ferroelectric domains in epitaxial PbTiO3 films on LaAlO3 substrate investigated by piezoresponse force microscopy and far-infrared reflectance
Authors: Simon E. , Borodavka F. , Gregora I. , Nuzhnyy D. , Kamba S. , Hlinka J. , Bartasyte A. , Margueron S.
Published: October 2011

Domain structures of 100–300 nm thin epitaxial films of ferroelectric PbTiO3 grown by metalorganic chemical vapor deposition technique on LaAlO3 perovskite substrate have been investigated by piezoresponse force microscopy and infrared reflectance spectroscopy techniques. Normal-incidence reflectance spectra reveal both E- and A1-symmetry modes of PbTiO3. The latter ones demonstrate the presence of a minor fraction of a-domains (with in-plane orientation of the spontaneous polarization) in the film. The piezoresponse force microscopy images allow to get local insight in the complex nanodomain architecture composed by few hundred nm large areas of primarily c/a/c/a but also a1/a2/a1/a2 domain pattern types, with participation of all six tetragonal ferroelectric domain states and both 180 ° and 90 ° ferroelectric walls.
Charged particle motion in electromagnetic fields varying moderately rapidly in space
Authors: Jagannath Aukosh , Weitzner Harold
Published: October 2011

Electromagnetic fields are considered which vary on the space scale of the geometric mean of the Larmor radius and the much larger scale length of variation of the magnetic field lines. It is first shown that the magnetic moment is an adiabatic invariant, even though the usual arguments for its existence fail. The motion of the guiding center is then examined. For perpendicular drifts in magnitude comparable with the particle speed, the subsequent motion is dominated by electrostatic effects. The motion of particles along the field lines occurs on a much slower time scale than the perpendicular drift time scale. When the guiding center motion is approximately periodic in time, a second adiabatic invariant exists, the magnetic flux enclosed by the almost periodic orbit. When the perpendicular drift is small compared with the particle speed, the parallel motion and the perpendicular drift occur on the same, slow timescale.
Non-linear dielectric properties of BiFeO3 ceramics
Authors: Curecheriu Lavinia , Gheorghiu Felicia , Ianculescu Adelina , Mitoseriu Liliana
Published: October 2011

The nonlinear dielectric properties of BiFeO3 ceramics as a function of temperature were investigated. The present results demonstrate a high dielectric tunability in quite low range of the bias electric fields over a broad temperature interval around the room temperature. The non-linear permittivity-field response results from multiple contributions, whose weights are different at various temperatures and in different field ranges.
Ab initioquantum dynamical study of photoinduced ring opening in furan
Authors: Gromov E. V. , Lévêque C. , Gatti F. , Burghardt I. , Köppel H.
Published: October 2011

The nonadiabatic photoinduced ring opening occurring in the two lowest excited singlet states of furan is investigated theoretically, using wave-packet propagation techniques. The underlying multidimensional potential energy surfaces (PESs) are obtained from ab initio computations, using the equation-of-motion coupled cluster method restricted to single and double excitations (EOM-CCSD), reported in earlier recent work [E. V. Gromov, A. B. Trofimov, F. Gatti, and H. Köppel, J. Chem. Phys. 133, 164309 (2010)10.1063/1.3493451]. Up to five nuclear degrees of freedom are considered in the quantum dynamical treatment. Four of them represent in-plane motion for which the electronic states in question (correlating with the valence 1B2(V) and Rydberg 1A2(3s) states at the C2v ground-state molecular configuration) have different symmetries, A′ and A′′, respectively. The fifth mode, representing out-of-plane bending of the oxygen atom against the carbon-atom plane, leads to an interaction of these states, as is crucial for the photoreaction. The nonadiabatic coupling and conical intersection cause an electronic population transfer on the order of ∼10 fs. Its main features, and that of the wave-packet motion, are interpreted in terms of properties of the PES. The lifetime due to the ring-opening process has been estimated to be around 2 ps. The dependence of this estimate on the nuclear degrees of freedom retained in the computations is discussed.
Theoretical investigation of the photophysics of methyl salicylate isomers
Authors: Massaro Richard D. , Blaisten-Barojas Estela
Published: October 2011

The photophysics of methyl salicylate (MS) isomers has been studied using time-dependent density functional theory and large basis sets. First electronic singlet and triplet excited states energies, structure, and vibrational analysis were calculated for the ketoB, enol, and ketoA isomers. It is demonstrated that the photochemical pathway involving excited state intramolecular proton transfer (ESIPT) from the ketoB to the enol tautomer agrees well with the dual fluorescence in near-UV (from ketoB) and blue (from enol) wavelengths obtained from experiments. Our calculation confirms the existence of a double minimum in the excited state pathway along the O–H–O coordinate corresponding to two preferred energy regions: (1) the hydrogen belongs to the OH moiety and the structure of methyl salicylate is ketoB; (2) the hydrogen flips to the closest carboxyl entailing electronic rearrangement and tautomerization to the enol structure. This double well in the excited state is highly asymmetric. The Franck-Condon vibrational overlap is calculated and accounts for the broadening of the two bands. It is suggested that forward and backward ESIPT through the barrier separating the two minima is temperature-dependent and affects the intensity of the fluorescence as seen in experiments. When the enol fluoresces and returns to its ground state, a barrier-less back proton transfer repopulates the ground state of methyl salicylate ketoB. It is also demonstrated that the rotamer ketoA is not stable in an excited state close to the desired emission wavelength. This observation eliminates the conjecture that the near-UV emission of the dual fluorescence originates from the ketoA rotamer. New experimental results for pure MS in the liquid state are reported and theoretical results compared to them.
Solitary wave evolution in a magnetized inhomogeneous plasma under the effect of ionization
Authors: Jyoti  , Malik Hitendra K.
Published: October 2011

A modified form of Korteweg-deVries (KdV) equation appropriate to nonlinear ion acoustic solitary waves in an inhomogeneous plasma is derived in the presence of an external magnetic field and constant ionization in the plasma. This equation differs from usual version of the KdV equation because of the inclusion of two terms arising due to ionization and density gradient present in the plasma. In this plasma, only the compressive solitary waves are found to propagate corresponding to the fast and slow modes. The amplitude of the solitary wave increases with an enhancement in the ionization for the fast mode as well as for the slow mode. The effect of magnetic field is to enhance the width of the solitary structure. The amplitude is found to increase (decrease) with an enhancement in charge number of the ions for the fast (slow) mode. The tailing structure becomes more (less) prominent with the rise in ion drift velocity for the case of fast (slow) mode.
On the gauge invariance of nonperturbative electronic dynamics using the time-dependent Hartree-Fock and time-dependent Kohn-Sham
Authors: Ding Feizhi , Liang Wenkel , Chapman Craig T. , Isborn Christine M. , Li Xiaosong
Published: October 2011

Nonperturbative electronic dynamics using the time-dependent Hartree-Fock (TDHF) and time-dependent Kohn-Sham (TDKS) theories with the adiabatic approximation is a powerful tool in obtaining insights into the interaction between a many-electron system and an external electromagnetic field. In practical applications of TDHF/TDKS using a truncated basis set, the electronic dynamics and molecular properties become gauge-dependent. Numerical simulations are carried out in the length gauge and velocity gauge to verify the extent of gauge-dependence using incomplete basis sets. Electronic dynamics of two many-electron systems, a helium atom and a carbon monoxide molecule in high-intensity linearly polarized radiation fields are performed using the TDHF and TDKS with two selected adiabatic exchange-correlation (xc) functionals. The time evolution of the expectation values of the dipole moment and harmonic spectra are calculated in the two gauges, and the basis set dependence on the gauge-invariance of these properties is investigated.
Enhanced carrier mobility and electrical stability of n-channel polymer thin film transistors by use of low-k dielectric buffer layer
Authors: Sunjoo Kim Felix , Hwang Do-Kyung , Kippelen Bernard , Jenekhe Samson A.
Published: October 2011

Insertion of a low-k polymer dielectric layer between the SiO2 gate dielectric and poly(benzobisimidazobenzophenanthroline) (BBL) semiconductor of n-channel transistors is found to increase the field-effect mobility of electrons from 3.6 × 10−4 cm2/Vs to as high as 0.028 cm2/Vs. The enhanced carrier mobility was accompanied by improved multicycling stability and durability in ambient air. Studies of a series of eight polymer dielectrics showed that the electron mobility increased exponentially with decreasing dielectric constant, which can be explained to result from the reduced energetic expense of charge-carrier/dipole interaction.
Growth of Ruddlesden-Popper type faults in Sr-excess SrTiO3 homoepitaxial thin films by pulsed laser deposition
Authors: Tokuda Y. , Kobayashi S. , Ohnishi T. , Mizoguchi T. , Shibata N. , Ikuhara Y. , Yamamoto T.
Published: October 2011

Ruddlesden-Popper (R.P.) type faults have been investigated for Sr-excess SrTiO3 (STO) homoepitaxial thin films by pulsed laser deposition (PLD) and tuning of the laser fluence. The R.P. type fault structures were found to depend on the amount of excess Sr. The growth direction of the planer faults changed from normal to normal and parallel to the substrate surface with an increase in excess Sr. Due to the directional change of the planer faults, the out-of-plane lattice shows lattice expansion. The results suggest that we can control the planer fault structures in STO thin films simply by changing the laser fluence in the PLD method.
N-type doping of poly(p-phenylene vinylene) with air-stable dopants
Authors: Lu Mingtao , Nicolai Herman T. , Wetzelaer Gert-Jan A. H. , Blom Paul W. M.
Published: October 2011

The electron transport in poly(p-phenylene vinylene) (PPV) derivatives blended with the air-stable n-type dopant (4-(1,3-dimethyl-2,3-dihydro-1H-benzoimidazol-2-yl)phenyl)dimethylamine (N-DMBI) is investigated. This dopant is activated after thin film deposition by annealing and strongly enhances the electron transport due to filling of electron traps as well as donation of free electrons to the lowest unoccupied molecular orbital (LUMO) of PPV. As a result, the electron current in a doped device exceeds the trap-free hole current. The total generated free electron density in the LUMO by the dopant typically amounts to 1023 m−3.
Effect of graded-temperature arsenic prelayer on quality of GaAs on Ge/Si substrates by metalorganic vapor phase epitaxy
Authors: Yu H. W. , Chang E. Y. , Yamamoto Y. , Tillack B. , Wang W. C. , Kuo C. I. , Wong Y. Y. , Nguyen H. Q.
Published: October 2011

The growth of GaAs epitaxy on Ge/Si substrates with an arsenic prelayer grown with graded temperature ramped from 300 to 420 °C is investigated. It is demonstrated that the graded-temperature arsenic prelayer grown on a Ge/Si substrate annealed at 650 °C not only improves the surface morphology (roughness: 1.1 nm) but also reduces the anti-phase domains’ (APDs) density in GaAs epitaxy (dislocation density: ∼2 × 107 cm−2). Moreover, the unwanted interdiffusion between Ge and GaAs epitaxy is suppressed by using the graded-temperature arsenic prelayer due to the low energy of the Ge-As bond and the use of a low V/III ratio of 20.
Resistance of Akt kinases to dephosphorylation through ATP-dependent conformational plasticity
Authors: Chan Tung O. , Zhang Jin , Rodeck Ulrich , Pascal John M. , Armen Roger S. , Spring Maureen , Dumitru Calin D. , Myers Valerie , Li Xue , Cheung Joseph Y. , Feldman Arthur M.
Published: October 2011

Phosphorylation of a threonine residue (T308 in Akt1) in the activation loop of Akt kinases is a prerequisite for deregulated Akt activity frequently observed in neoplasia. Akt phosphorylation in vivo is balanced by the opposite activities of kinases and phosphatases. Here we describe that targeting Akt kinase to the cell membrane markedly reduced sensitivity of phosphorylated Akt to dephosphorylation by protein phosphatase 2A. This effect was amplified by occupancy of the ATP binding pocket by either ATP or ATP-competitive inhibitors. Mutational analysis revealed that R273 in Akt1 and the corresponding R274 in Akt2 are essential for shielding T308 in the activation loop against dephosphorylation. Thus, occupancy of the nucleotide binding pocket of Akt kinases enables intramolecular interactions that restrict phosphatase access and sustain Akt phosphorylation. This mechanism provides an explanation for the “paradoxical” Akt hyperphosphorylation induced by ATP-competitive inhibitor, A-443654. The lack of phosphatase resistance further contributes insight into the mechanism by which the human Akt2 R274H missense mutation may cause autosomal-dominant diabetes mellitus.
Three-dimensional superresolution colocalization of intracellular protein superstructures and the cell surface in live
Caulobacter crescentus
Authors: Lew Matthew D. , Lee Steven F. , Ptacin Jerod L. , Lee Marissa K. , Twieg Robert J. , Shapiro Lucy , Moerner W. E.
Published: October 2011

Recently, single-molecule imaging and photocontrol have enabled superresolution optical microscopy of cellular structures beyond Abbe’s diffraction limit, extending the frontier of noninvasive imaging of structures within living cells. However, live-cell superresolution imaging has been challenged by the need to image three-dimensional (3D) structures relative to their biological context, such as the cellular membrane. We have developed a technique, termed superresolution by power-dependent active intermittency and points accumulation for imaging in nanoscale topography (SPRAIPAINT) that combines imaging of intracellular enhanced YFP (eYFP) fusions (SPRAI) with stochastic localization of the cell surface (PAINT) to image two different fluorophores sequentially with only one laser. Simple light-induced blinking of eYFP and collisional flux onto the cell surface by Nile red are used to achieve single-molecule localizations, without any antibody labeling, cell membrane permeabilization, or thiol-oxygen scavenger systems required. Here we demonstrate live-cell 3D superresolution imaging of Crescentin-eYFP, a cytoskeletal fluorescent protein fusion, colocalized with the surface of the bacterium
Caulobacter crescentus
using a double-helix point spread function microscope. Three-dimensional colocalization of intracellular protein structures and the cell surface with superresolution optical microscopy opens the door for the analysis of protein interactions in living cells with excellent precision (20–40 nm in 3D) over a large field of view (12 × 12 μm).
Recruitment of cellular prion protein to mitochondrial raft-like microdomains contributes to apoptosis execution
Authors: Mattei Vincenzo , Matarrese Paola , Garofalo Tina , Tinari Antonella , Gambardella Lucrezia , Ciarlo Laura , Manganelli Valeria , Tasciotti Vincenzo , Misasi Roberta , Malorni Walter , Sorice Maurizio
Published: October 2011

We examined the possibility that cellular prion protein (PrPC) plays a role in the receptor-mediated apoptotic pathway. We first found that CD95/Fas triggering induced a redistribution of PrPC to the mitochondria of T lymphoblastoid CEM cells via a mechanism that brings into play microtubular network integrity and function. In particular, we demonstrated that PrPC was redistributed to raft-like microdomains at the mitochondrial membrane, as well as at endoplasmic reticulum-mitochondria–associated membranes. Our in vitro experiments also demonstrated that, although PrPC had such an effect on mitochondria, it induced the loss of mitochondrial membrane potential and cytochrome c release only after a contained rise of calcium concentration. Finally, the involvement of PrPC in apoptosis execution was also analyzed in PrPC-small interfering RNA–transfected cells, which were found to be significantly less susceptible to CD95/Fas–induced apoptosis. Taken together, these results suggest that PrPC might play a role in the complex multimolecular signaling associated with CD95/Fas receptor–mediated apoptosis.
DHHC-7 and -21 are palmitoylacyltransferases for sex steroid receptors
Authors: Pedram Ali , Razandi Mahnaz , Deschenes Robert J. , Levin Ellis R
Published: October 2011

Classical estrogen, progesterone, and androgen receptors (ERs, PRs, and ARs) localize outside the nucleus at the plasma membrane of target cells. From the membrane, the receptors signal to activate kinase cascades that are essential for the modulation of transcription and nongenomic functions in many target cells. ER, PR, and AR trafficking to the membrane requires receptor palmitoylation by palmitoylacyltransferase (PAT) protein(s). However, the identity of the steroid receptor PAT(s) is unknown. We identified the DHHC-7 and -21 proteins as conserved PATs for the sex steroid receptors. From DHHC-7 and -21 knockdown studies, the PATs are required for endogenous ER, PR, and AR palmitoylation, membrane trafficking, and rapid signal transduction in cancer cells. Thus the DHHC-7 and -21 proteins are novel targets to selectively inhibit membrane sex steroid receptor localization and function.
Associations between serum total bilirubin levels and functional dependence in the elderly
Authors: Kao T. W. , Chou C. H. , Wang C. C. , Chou C. C. , Hu J. , Chen W. L.
Published: October 2011

Background

Many studies support the role of bilirubin as a cytoprotector in chronic inflammatory diseases, such as stroke and atherosclerosis.

Aim

To investigate the relationship between serum total bilirubin levels and functional dependence in older adults.

Methods

Data from the National Health and Nutrition Examination Survey (1999–2002) pertaining to 2235 old adults were analysed. All participants had given a household interview, providing information of five major domains on self‐reported functional status (activities of daily living, instrumental activities of daily living, leisure and social activities, lower extremity mobility and general physical activities), had completed serum total bilirubin measurement, and a questionnaire regarding personal health. Poor performance was defined as experiencing difficulty with one or more items in a given domain. Functional dependence was defined as having three or more poor performances in the five major domains. Multiple logistic regression was performed together with quartile‐based stratified odds ratio (OR) comparison and trend tests.

Results

The OR of functional dependence for each standard deviation increment in the serum total bilirubin level was 0.56 (P = 0.002). After additional adjustment, the inverse association remained essentially unchanged. In quartile‐based analysis, participants with higher quartiles of serum total bilirubin tended to have lower ORs of functional dependence. The trends of lower likelihood of functional dependence across increasing quartiles of the serum total bilirubin level were statistically significant (P < 0.05 for all trends).

Conclusions

Higher serum total bilirubin levels were associated with lower likelihood of functional dependence in older adults.
Effect of oxygen versus adaptive pressure support servo‐ventilation in patients with central sleep apnoea–Cheyne Stokes respiration and congestive heart failure
Authors: Campbell A. J. , Ferrier K. , Neill A. M.
Published: October 2011

Background and Aims

Central sleep apnoea with Cheyne‐Stokes respiration (CSA‐CSR) is a common, serious consequence of congestive heart failure. Optimal treatment is yet to be established. We compared two common treatments for CSA‐CSR.

Methods

Subjects with CSA‐CSR and stable congestive heart failure were randomised to 8 weeks treatment: oxygen 2 L/min through nasal prongs and concentrator or 8 weeks adaptive servo‐ventilation (ASV) using a crossover design separated by a 3‐week washout. Polysomnography, indices of sleep and breathing, shuttle walk distance, symptoms, urinary catecholamines, plasma brain natriuretic peptide (NT‐BNP) and echocardiography were collected at baseline and completion of each arm.

Results

Ten subjects (age 64 ± 10 years, left ventricular ejection fraction (LVEF) 28 ± 10.5%, apnoea‐hypopnoea index (AHI) 63 ± 30/h) were recruited. Seven completed the protocol (one died, one refused ASV, one was withdrawn after hospital admission). On therapy, an AHI of < 10/h was achieved in two out of seven using oxygen (29%), six of seven using ASV (86%) and six of seven with either (86%). Compliance with ASV: 5.2 ± 2 h/night (range 1.45–7.1 h/night). Median AHI on oxygen therapy: 13.4 /h (range 2.6–42.9/h), ASV, 1.4 /h (range 0.6–17.8/h, P = 0.03). LVEF was not changed by either therapy (oxygen 30.9% vs 30.9% P = 0.97, ASV 32.5% vs 35.0% P = 0.24). NT‐BNP, urinary catecholamines, shuttle walk distance and symptoms were not significantly changed by either therapy.

Conclusion

CSA‐CSR is reduced to a greater extent by ASV than oxygen therapy over 8 weeks but was not accepted long term. Neither treatment improved prognostic indices of heart failure or symptoms in the short term.