bluuebunny/crossref_metadata_2025_split huggingface dataset:
A constrained variational approach to the designing of low transport band gap materials: A multiobjective random mutation hill climbing method
Authors: Sarkar Kanchan , Sharma Rahul , Bhattacharyya S. P. 
Published: July 2011

AbstractNeutral polythiophene (PT) and polyselenophene (PSe) are semiconductors with band gaps of about 2 eV. We have proposed and implemented a constrained variational method in which total energy of neutral PT or PSe oligomers is minimized under the constraint that the band gap measured by HOMO–LUMO energy difference is also a minimum in each case. The constrained (bimodal) minimization has been carried out by an adaptive random mutation hill climbing method within the basic framework of Su‐Schrieffer‐Heeger type of model. We show that the “band‐gap constrained minimization” automatically creates electron deficient quinoid regions (QR) in the PT or PSe chains, embedded in aromatic regions (ARs), on both sides. We have investigated how the number and distribution of such QRs can reduce the band gap. Band gap constrained electronic structure calculations thus provide designing clues for low transport band gap materials based on molecular chromophores. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012
Pyrrolidine‐based dye‐sensitized solar cells: A time‐dependent density functional theory investigation of the excited state electronic properties
Authors: Preat Julien , Michaux Catherine , André Jean‐Marie , Perpète Eric A. 
Published: July 2011

AbstractThis work reports a theoretical study of the excited state properties of a series of original conjugated metal‐free organic dyes containing the pyrrolidine (PYR) moiety. These compounds have recently been developed for dye‐sensitized solar cells (DSSCs). Our polarizable continuum model time‐dependent density functional theory‐based procedure made it possible to efficiently and accurately evaluate (i) the vertical excitation energies, (ii) the related redox potentials, and (iii) the free enthalpies of injection. It turns out that the Becke‐Half‐and‐Half‐Lee‐Yang‐Parr functional, combined to the 6‐311+G(2d,2p) basis set, gives reliable auxochromic shifts when the bulk solvation effects are included in the model. Indeed, the theoretical procedure provides excitation energies with a mean absolute deviation limited to ∼0.10 eV only. In addition, we give insights into the geometrical and electronic structures of the dyes, and we unravel the structural modifications that optimize the properties of PYR‐based DSSCs. This investigation aims at improving the electron injection process, as well as the light harvesting efficiency (LHE) of the dyes. For this purpose, we considered a set of 17 new dyes, and starting from the basic five‐block [PYR]‐[phenyl]‐[ethylene]‐[thiophene]‐[cyano acrylic acid] system (PYR‐m′ structure), several modifications leading to better electron injection and comparable LHE properties have been proposed. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012
Molecular conductance in relation to inverse transport theory and to chemical bond order
Authors: Klein D. J. , March N. H. 
Published: July 2011

AbstractMcCaskill and March (MM) have derived a resistivity theory in the form of a quotient, the numerator of which is a force–force correlation function. The denominator has the form 1 − b, where MM forge a link between the quantity b and bound states. Evidently, as b tends to unity, one approaches a metal‐insulator transition, which has potential relevance for molecular conductance. In addition, Klein was involved in early work in this area, in which contact is established with chemical bond order. Practical examples of this are discussed in this article. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012
Exact S‐wave solution of the trigonometric pöschl‐teller potential
Authors: Hamzavi M. , Rajabi A. A. 
Published: July 2011

AbstractThe trigonometric Pöschl‐Teller (PT) potential describes the diatomic molecular vibration. By using the Nikiforov‐Uvarov method, we have obtained the exact analytical s‐wave solutions of the radial Schrödinger equation (SE) for the trigonometric PT potential. The energy eigenvalues and corresponding eigenfunctions are calculated in closed forms. Some numerical results are presented too. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012
Gauge function optimization 2: An accurately solvable model
Authors: Kubo Atsushi 
Published: July 2011

AbstractThe gauge function is optimized by using the Kennedy–Kobe (KK) theory [Kennedy and Kobe, Phys Rev A, (1984) 30, 51] for the anisotropic harmonic oscillator model in a magnetic field. We extend the KK model to describe various electron density distributions, which resemble to those for the ground and excited states of a Hion. The almost divergence‐free current densities can be obtained by this method. The convergence is the fastest for the h2 model without the node of the wavefunction. When the wavefunction has nodal points, the first‐ and the second‐order derivatives of the gauge function diverge at the nodes. We examine these singularities of the gauge function near the nodes both numerically and analytically. We also investigate the computed divergence‐free current density in detail. Many new stagnation vortices appear after the gauge function optimization. The positions of the vortices are compared with those of the electron density maxima. When the maxima are separated from each other, some correlations are found between them. We also investigate the nuclear cusp condition of current density by inspecting the solutions of the KK equation when the electron density has a cusp. We find that the local mean velocity becomes aC0continuous function at the nucleus. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012
Cell‐penetrating peptide induces various deformations of lipid bilayer membrane: Inverted micelle, double bilayer, and transmembrane
Authors: Kawamoto Shuhei , Miyakawa Takeshi , Takasu Masako , Morikawa Ryota , Oda Tatsuki , Saito Hiroaki , Futaki Shiroh , Nagao Hidemi 
Published: July 2011

AbstractWe investigated the deformation of lipid bilayer membrane by cell‐penetrating peptide using coarse‐grained molecular dynamics simulation. The simulations have been performed with different values of two parameters, strength of angle potential of lipid and strength of attractive interaction between peptide and lipid heads. We obtained the phase diagram of deformation of membrane and found that there are four kinds of structures such as surface dent, inverted micelle, double bilayer, and transmembrane. The results suggest that one peptide can make various structures on lipid bilayer membrane. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012
Tunable coulomb blockade and giant coulomb blockade magnetoresistance in a double quantum dot system
Authors: Zhang X.‐G. , Xiang T. 
Published: July 2011

AbstractWe propose a Hubbard model to describe the tunneling effect of electrons in a double quantum dot system connected in the parallel circuit configuration to electrodes. The change in the interdot coupling is shown to dramatically influence the Coulomb blockade (CB) properties. For magnetic double dots, the interdot coupling can be tuned by the external magnetic field, leading to a giant CB magnetoresistance. Possible detection of this effect in organic magnetic molecular systems is discussed. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012
Methods to elicit experts’ beliefs over uncertain quantities: application to a cost effectiveness transition model of negative pressure wound therapy for severe pressure ulceration
Authors: Soares Marta O. , Bojke Laura , Dumville Jo , Iglesias Cynthia , Cullum Nicky , Claxton Karl 
Published: July 2011

We can use decision models to estimate cost effectiveness, quantify uncertainty regarding the adoption decision and provide estimates of the value of further research. In many cases, the existence of only limited data with which to populate a decision model can mean that a cost‐effectiveness analysis either does not proceed or may misrepresent the degree of uncertainty associated with model inputs. An example is the case of negative pressure wound therapy (NPWT) used to treat severe pressure ulceration, for which the evidence base is limited and sparse. There is, however, substantial practical experience of using this treatment and its comparators. We can capture this knowledge quantitatively to inform a cost‐effectiveness model by eliciting beliefs from experts.This paper describes the design and conduct of an elicitation exercise to generate estimates of multiple uncertain model inputs and validate analytical assumptions for a decision model on the use of NPWT. In designing the exercise, the primary focus was the use of elicitation to inform decision models (multistate models), where representations of uncertain beliefs need to be probabilistically coherent. This paper demonstrates that it is feasible to collect formally elicited evidence to inform decision models. Copyright © 2011 John Wiley & Sons, Ltd.
Long‐Range Nanoparticle Surface‐Energy‐Transfer Ruler for Monitoring Photothermal Therapy Response
Authors: Singh Anant K. , Lu Wentong , Senapati Dulal , Khan Sadia Afrin , Fan Zhen , Senapati Tapas , Demeritte Teresa , Beqa Lule , Ray Paresh Chandra 
Published: July 2011

AbstractA recent gold nanotechnology‐driven approach opens up a new possibility for the destruction of cancer cells through photothermal therapy. Ultimately, photothermal therapy may enter into clinical therapy and, as a result, there is an urgent need for techniques to monitor the tumor response to therapy. Driven by this need, a nanoparticle surface‐energy‐transfer (NSET) approach to monitor the photothermal therapy process by measuring a simple fluorescence intensity change is reported. The fluorescence intensity change is due to the light‐controlled photothermal release of single‐stranded DNA/RNA via dehybridization during the therapy process. Time‐dependent results show that just by measuring the fluorescence intensity change, the photothermal therapy response during the therapy process can be monitored. The possible mechanism and operating principle of the NSET assay are discussed. Ultimately, this NSET assay could have enormous potential applications in rapid, on‐site monitoring of the photothermal therapy process, which is critical to providing effective treatment of cancer and multidrug‐resistant bacterial infections.
Elementary students' views of explanation, argumentation, and evidence, and their abilities to construct arguments over the school year
Authors: McNeill Katherine L. 
Published: July 2011

AbstractScience includes more than just concepts and facts, but also encompasses scientific ways of thinking and reasoning. Students' cultural and linguistic backgrounds influence the knowledge they bring to the classroom, which impacts their degree of comfort with scientific practices. Consequently, the goal of this study was to investigate 5th grade students' views of explanation, argument, and evidence across three contexts—what scientists do, what happens in science classrooms, and what happens in everyday life. The study also focused on how students' abilities to engage in one practice, argumentation, changed over the school year. Multiple data sources were analyzed: pre‐ and post‐student interviews, videotapes of classroom instruction, and student writing. The results from the beginning of the school year suggest that students' views of explanation, argument, and evidence, varied across the three contexts with students most likely to respond “I don't know” when talking about their science classroom. Students had resources to draw from both in their everyday knowledge and knowledge of scientists, but were unclear how to use those resources in their science classroom. Students' understandings of explanation, argument, and evidence for scientists and for science class changed over the course of the school year, while their everyday meanings remained more constant. This suggests that instruction can support students in developing stronger understanding of these scientific practices, while still maintaining distinct understandings for their everyday lives. Finally, the students wrote stronger scientific arguments by the end of the school year in terms of the structure of an argument, though the accuracy, appropriateness, and sufficiency of the arguments varied depending on the specific learning or assessment task. This indicates that elementary students are able to write scientific arguments, yet they need support to apply this practice to new and more complex contexts and content areas. © 2011 Wiley Periodicals, Inc. J Res Sci Teach 48: 793–823, 2011
Emotion and perception: the role of affective information
Authors: Zadra Jonathan R. , Clore Gerald L. 
Published: July 2011

AbstractVisual perception and emotion are traditionally considered separate domains of study. In this article, however, we review research showing them to be less separable than usually assumed. In fact, emotions routinely affect how and what we see. Fear, for example, can affect low‐level visual processes, sad moods can alter susceptibility to visual illusions, and goal‐directed desires can change the apparent size of goal‐relevant objects. In addition, the layout of the physical environment, including the apparent steepness of a hill and the distance to the ground from a balcony can both be affected by emotional states. We propose that emotions provide embodied information about the costs and benefits of anticipated action, information that can be used automatically and immediately, circumventing the need for cogitating on the possible consequences of potential actions. Emotions thus provide a strong motivating influence on how the environment is perceived. WIREs Cogni Sci 2011 2 676–685 DOI: 10.1002/wcs.147This article is categorized under:

Psychology > Emotion and Motivation
Transfer RNA travels from the cytoplasm to organelles
Authors: Rubio Mary Anne T. , Hopper Anita K. 
Published: July 2011

AbstractTransfer RNAs (tRNAs) encoded by the nuclear genome are surprisingly dynamic. Although tRNAs function in protein synthesis occurring on cytoplasmic ribosomes, tRNAs can transit from the cytoplasm to the nucleus and then again return to the cytoplasm by a process known as the tRNA retrograde process. Subsets of the cytoplasmic tRNAs are also imported into mitochondria and function in mitochondrial protein synthesis. The numbers of tRNA species that are imported into mitochondria differ among organisms, ranging from just a few to the entire set needed to decode mitochondrially encoded mRNAs. For some tRNAs, import is dependent on the mitochondrial protein import machinery, whereas the majority of tRNA mitochondrial import is independent of this machinery. Although cytoplasmic proteins and proteins located on the mitochondrial surface participating in the tRNA import process have been described for several organisms, the identity of these proteins differ among organisms. Likewise, the tRNA determinants required for mitochondrial import differ among tRNA species and organisms. Here, we present an overview and discuss the current state of knowledge regarding the mechanisms involved in the tRNA retrograde process and continue with an overview of tRNA import into mitochondria. Finally, we highlight areas of future research to understand the function and regulation of movement of tRNAs between the cytoplasm and organelles. WIREs RNA 2011 2 802–817 DOI: 10.1002/wrna.93This article is categorized under:

RNA Processing > tRNA Processing
RNA Export and Localization > Nuclear Export/Import
RNA Export and Localization > RNA Localization
Osteoprotegerin (OPG) and Related Proteins (RANK, RANKL and TRAIL) in Thyroid Disease
Authors: Sood Sumit K. , Balasubramanian Sabapathy , Higham Sue , Fernando Malee , Harrison Barney 
Published: July 2011

AbstractBackgroundOsteoprotegerin (OPG), receptor activator of nuclear factor kappaB (RANK), RANK ligand (RANKL), and TNF related apoptosis inducing ligand (TRAIL) are the key proteins in the development of bone metastases. Osteoprotegerin improves tumor cell survival and inhibits TRAIL induced apoptosis of cancer cell lines. It also binds to RANKL and inhibits its interaction with RANK (cell surface receptor), which influences osteoclast formation and function. The aim of the present study was to characterize the expression of OPG, RANK, RANKL, and TRAIL in benign and malignant thyroid tissue and thyroid cell lines.MethodsArchived thyroid tissue from 79 patients (60 differentiated thyroid cancers and 19 benign thyroids) was stained for OPG, RANK, RANKL, and TRAIL by immunohistochemistry. Staining was assessed semiquantitatively and correlated with pathology. Western blots were performed on three human thyroid cell lines: Nthy‐ori 3‐1 (thyroid follicular epithelium), FTC‐133 (follicular thyroid carcinoma), and K1E7 (subclone of papillary thyroid carcinoma).ResultsOsteoprotegerin and RANKL staining was cytoplasmic; RANK staining was nuclear; and TRAIL staining was predominantly cytoplasmic. All four proteins were expressed in benign and malignant tissue. There was significant difference in RANK expression between malignant and benign tissue (8 vs. 84%, respectively; Fisher’s exact test; P < 0.001). RANKL expression was significantly increased in malignant tissue (Fisher’s exact test; P = 0.04). Western blotting showed OPG expression in all cell lines and TRAIL in none. RANK and RANKL were not detected in papillary and follicular cell lines, respectively.ConclusionsNuclear expression of RANK protein in thyroid tissue is paradoxical; it could be due to nuclear migration after ligand binding. Suppression of RANK and increased expression of RANKL in malignant tissue warrant further investigation.
Determination of Underivatized Long Chain Fatty Acids Using HPLC with an Evaporative Light‐Scattering Detector
Authors: Guo Hui , Hu Chen , Qian Junqing , Wu De 
Published: July 2011

AbstractA high‐performance liquid chromatographic method with an evaporative light‐scattering detector has been developed for the separation and quantitative analysis of four underivatized long chain fatty acids in four different oil matrices. An isocratic elution mode using methanol/water/acetic acid and an Agilent Eclipse XDB‐C18 analytical column was used. Calibration curves of the four fatty acids (FA) were well correlated (r2 > 0.999) within the range of 1–10 mg mL−1 for linoleic acid, 0.8–10 mg mL−1 for stearic acid and 0.5–10 mg mL−1 for the other FA. Four oil samples were examined; camellia oil, olive oil, Brucea javanica oil and sesame oil. Good agreement was found with the standard gas chromatographic (GC) method. The proposed method offers distinct advantages over the official GC method; better separation and precision, and the sample components do not need to be derivatized.
Cr-spinel compositions in serpentinites and their implications for the petrotectonic history of the Zagros Suture Zone, Kurdistan Region, Iraq
Authors: ASWAD KHALID J. A. , AZIZ NABAZ R. H. , KOYI HEMIN A. 
Published: July 2011

AbstractAccessory chrome spinels are scattered throughout the serpentinite masses in two allochthonous thrust sheets belonging to the Penjween–Walash sub-zone of the northwestern Zagros Suture Zone in Kurdistan. Based on field evidence, the serpentinites are divided into two groups: (1) highly sheared serpentinites (110–80 Ma), which occupy the lower contact of the ophiolitic massifs of the Upper Allochthonous sheet (Albian–Cenomanian age), and (2) ophiolitic mélange serpentinites of mixed ages (150 and 200 Ma) occurring along thrust faults on the base of the volcano-sedimentary segment (42–32 Ma) of the Lower Allochthonous sheet. The Cr-spinels of both groups show a wide range of YCr(Cr/(Cr + Al) atomic ratio) from 0.37 to 1.0, while the XMg(Mg/(Mg + Fe2+) atomic ratio) ranges from 0.0 to 0.75. Based on the Cr-spinel compositions of the entire dataset and in conjunction with back-scattered electron imaging, from core to rim, three spinel stages have been recognized: the residual mantle stage, a Cr-rich stage and a third stage showing a very narrow magnetite rim. These three stages are represented by primary Cr-spinel, pre-serpentinization metamorphosed spinel and syn- or post-serpentinization spinel, respectively. The chemical characteristics of primary (first-stage) Cr-spinels of both serpentinite groups indicate a tectonic affinity within a fore-arc setting of peridotite protoliths. The second stage indicates that Cr-spinels have undergone subsolidus re-equilibration as a result of solid–solid reaction during pre-serpentinization cooling of the host rock. Here the primary Cr-spinel compositions have been partly or completely obscured by metamorphism. During the third stage, the Cr-spinels have undergone solid–fluid re-equilibration during syn- or post-serpentinization processes. Both the second and third stages point to diachronous metamorphic paths resulting from continuous tectonic evolution influenced by either slow or fast uplift of mantle protoliths. In the fast metamorphic paths, the primary chrome spinels are flanked by a very narrow magnetite rim. The presence of two groups of distally separated serpentinites with different emplacement ages and fore-arc tectonic affinity could indicate that the closure of the Tethys Ocean culminated in two fortuitous subduction processes.
Interaction energy and closest approach of moving charged particles on a plasma and neutral gas background
Authors: ØIEN ALF H. 
Published: July 2011

AbstractElectric interaction between two negatively charged particles of different sizes on a mixed background of positive, negative, and neutral particles is complex and has relevance both to dusty plasmas and to transports in ionized fluids in general. We consider particularly effects during interaction that particle velocity and neutrals in the background may have on the well-known “dressing” and electric shielding that is due to the charged part of the background and how the interaction energy is modified because of this. Without such effects earlier works show the interaction becomes attractive when the distance between the two particles is a bit larger than the Debye length. We use a model where one of the two interacting particles has a radius much larger than the Debye length and the other a radius shorter than the Debye length. Then, the complex interaction may be more easily determined for particle separation up to a few Debye lengths. We consider the larger particle as stationary while the smaller may move. We find quite simple analytic expressions for the dressed particle interaction energy over the whole range of speed of the incoming smaller particle, assumed coming head on the larger particle, and the whole range of neutral particle densities. We also derive a distance of closest approach of small and large particles for all such parameter values. This distance is important for excluded volume estimations for moving small charged particles in media populated by large charged particles on a background as described above, and hence, important for determining the speed of flow of the smaller particles through such media.