bluuebunny/crossref_metadata_2025 huggingface dataset:
Image semantics in the description and categorization of journalistic photographs
Authors: Laine‐Hernandez Mari , Westman Stina
Published: October 2007

This paper reports a study on the description and categorization of images. The aim of the study was to evaluate existing indexing frameworks in the context of reportage photographs and to find out how the use of this particular image genre influences the results. The effect of different tasks on image description and categorization was also studied. Subjects performed keywording and free description tasks and the elicited terms were classified using the most extensive one of the reviewed frameworks. Differences were found in the terms used in constrained and unconstrained descriptions. Summarizing terms such as abstract concepts, themes, settings and emotions were used more frequently in keywording than in free description. Free descriptions included more terms referring to locations within the images, people and descriptive terms due to the narrative form the subjects used without prompting. The evaluated framework was found to lack some syntactic and semantic classes present in the data and modifications were suggested. According to the results of this study image categorization is based on high‐level interpretive concepts, including affective and abstract themes. The results indicate that image genre influences categorization and keywording modifies and truncates natural image description.
A conception‐based approach to automatic subject term assignment for scientific journal articles
Authors: Chung EunKyung , Hastings Samantha K.
Published: October 2007

This study proposes a conception‐based approach to automatic subject term assignment when using Text Classification (TC) techniques. From the perspective of conceptual and theoretical views of subject indexing, this study identifies three conception‐based approaches, Domain‐Oriented, Document‐Oriented, and Content‐Oriented, in conjunction with eight semantic sources in typical scientific journal articles. Based on the identification of semantic sources and conception‐based approaches, the experiment explores the significance of individual semantic sources and conception‐based approaches for the effectiveness of subject term assignment. The results of the experiment demonstrate that some semantic sources and conception‐based approaches are better performers than the full text‐based approach which has been dominant in TC fields. In fact, this study indicates that subject terms are better assigned by TC techniques when the indexing conceptions are considered in conjunction with semantic sources.
Semantic visual features in content‐based video retrieval
Authors: Mu Xiangming
Published: October 2007

A new semantic visual features (e.g., car, mountain, and fire) navigation technology is proposed to improve the effectiveness of video retrieval. Traditional temporal neighbor browsing technology allows users to navigate temporal neighbors of a selected sample frame to find additional matches, while semantic visual feature browsing enables users to navigate keyframes that have similar features to the selected sample frame. A pilot evaluation was conducted to compare the effectiveness of three video retrieval designs that support 1) temporal neighbor browsing; 2) semantic visual feature browsing; and 3) fused browsing which is a combination of both temporal neighbor and semantic visual feature browsing. Two types of searching tasks: visual centric and non‐visual centric tasks were applied. Initial results indicated that the semantic visual feature browsing system was more efficient for non‐visual centric tasks.
Authorship, incentives for creation, and copyright in the digital 21st century
Authors: Campbell James
Published: October 2007

Copyright in the United States is under enormous stress in the digital age. The cause of this stress is often described in technological terms, yet there are deeper systemic policy and legal factors at play. Specifically, there is an ever‐increasing, and increasingly obvious, disconnect between the constitutionally based justification for copyright, and copyright's lived out implementation. That is particularly true regarding two key justifications for the expansions of copyright protection that have occurred since 1790: the concept of the author, and the necessity of providing a high level of control and financial incentives to authors to encourage the production of socially valuable works.

This paper examines both of these justifications for expanded copyright protection and finds them unproven and, in fact, significantly lacking force under both philosophical and empirical analysis. We suggest that the U.S. abandon those justifications for copyright in today's digital world. We offer eight principles upon which a more integrated and relevant copyright system could be based, one in which policy, law, and practice could be brought into coherence so that today's stresses on copyright would be minimized, and the Constitutional charge to promote "the Progress of Science and useful Arts" would be maximized for society as a whole.
Trailblazing through a Knowledge Space of Science: Forward Citation Expansion in CiteSeer
Authors: Chen Chaomei , Lin Xia , Zhu Weizhong
Published: October 2007

Understanding emerging trends and patterns in science and technology is essential not only to scientists and engineers in their own fast‐advancing fields but also to a wide variety of individuals and organizations who are also interested in tracking the development of thematic topics. This is a challenging task because many existing tools are not particularly designed to deal with the dynamics of intellectual structures that transcend the boundaries of individual documents or isolated topics. In this article, we introduce a conceptual and operational platform that extends the traditional notion of traveling along individual citation pathways and defines operators for recursive and holistic theme expansion based on citation connectivity. We describe the implementation of a forward expansion operator and illustrate its potential with the CiteSeer metadata. In addition, we integrate the forward expansion operators with information visualization techniques.
Standards in electronic resource management
Authors: Kasprowski Rafal , Koppel Ted , Robertson Nathan D.M.
Published: October 2007

Following last year's panel on developments in electronic resource management (ERM), the 2006 panel will discuss ERM standards. The deliverables published by the Digital Library Federation's Electronic Resource Management Initiative (DLF ERMI) had a decisive impact on the development of ERM systems and created a demand by the library, vendor, and publisher communities for further standardization in the area. In the second phase of the group's work (ERMI 2), a major objective is to develop standards for the collection of license information and usage statistics, which would reduce the administrative costs of both data sets. The need for ERM standardization has led the stakeholders to collaborate. ERMI 2 and EDItEUR are attempting to incorporate the data elements proposed by ERMI into the ONIX family of publisher data standards. The DLF/NISO/EDItEUR/PLS License Expression Working Group (LEWG) is participating in the development of license standards in part based on the work of ERMI and EDItEUR. The Standardized Usage Statistics Harvesting Initiative (SUSHI) is developing a standard model for retrieving usage data. As a result, license data available in a single data container could be downloaded directly into ERM systems, as would usage statistics thanks to a platform‐independent protocol for retrieving COUNTER‐compliant data.
Anarchists, pirates, ideologists, and disasters: New digital trends and their impacts
Authors: Shachaf Pnina , Hara, Noriko , Eschenfelder Kristin , Goodrum Abby , Scott Lori Cooke , Shankar Kalpana , Ozakca Muzaffer , Robbin, Alice
Published: October 2007

This panel will address both online disasters created by anarchists and pirates and disaster relief efforts aided by information and communication technologies (ICTs). An increasing number of people use (ICTs) to mobilize their resources and enhance their activities. This mobilization has unpredictable consequences for society: On one hand, use of ICT has allowed for the mobilization of millions of people for disaster relief efforts and peace movements. On the other hand, it has also helped hackers, pirates to carryout destructive activities. In many cases it is hard to judge the moral consequences of the use of ICT by marginalized groups.

The panel will present five studies of which three will focus on online disobedience and two will focus on ICT use for disaster. Together these presentations illustrate both positive and negative consequences of the new digital trends. Goodrum deliberates on an ethic of hacktivism in the context of online activism. Eschenfelder discusses user modification of or resistance to technological protection measures. Shachaf and Hara present a study of anarchists who attack information posted on Wikipedia and modify the content by deleting, renaming, reinterpreting, and recreating information according to their ideologies. Scott examines consumer media behaviors after hurricane Katrina and Rita disasters. Shankar and Ozakca discuss volunteer efforts in the aftermath of hurricane Katrina.
The current status of Open Access in biomedical field: the comparison of countries relating to the impact of national policies
Authors: Matsubayashi Mamiko , Kurata Keiko , Sakai Yukiko , Morioka Tomoko , Kato Shinya , Mine Shinji , Ueda Shuichi
Published: October 2007

The purpose of the article is to show the current status of Open Access (OA) in biomedical field, and compare some countries such as the U.S., the U.K. and Japan in terms of the OA situation. There are controversies about the definition of OA. After examining the requirements about OA, we recognized OA as the situation in which researchers could read the full text of articles in unrestricted way. In order to investigate the current situation of OA, 4,756 articles were sampled randomly from articles published between January and September in 2005 and indexed in PubMed. The main results are as follows: 1) The rate of OA articles was 25%, and 75% of all the articles were available online including electronic subscription journal articles. 2) The means of OA was classified into five types. Among them, the rate of OA articles by “OA and Hybrid OA journals” was overwhelming (more than 70%), and that of PMC was 26.2%. The rates of OA articles by “institutional repositories” and “authors' personal sites” were considerably low (6.0% and 4.9% respectively). 3) When comparing the rates of OA articles by countries, Belgium ranked the first with 41.7%. The five countries indicated more than 30% in OA articles: Canada and India (38.7%), Brazil (36.4%), Australia (30.8%), and the U.S. (30.7%). Each country was different in the means of OA. 4) We explored the rates of OA for two groups; one group consists of articles published in journals with IF, and the other consists of articles published in journals without IF. The rate of OA for the group of articles in journals with IF is 20.6%, and that of articles in journals without IF is 30.8%.
Secondary scrotal lymphedema: A novel microsurgical approach
Authors: Mukenge Sylvain , Pulitanò Carlo , Colombo Renzo , Negrini Daniela , Ferla Gianfranco
Published: October 2007

Secondary scrotal lymphedema is an infrequent complication of radical cystectomy assiociated with pelvic lymphadenectomy. We report a case of secondary lymphedema of male genitalia presenting more than 4 years after a radical cystectomy with extended pelvic lymphadenectomy for adenocarcinoma of the bladder. Microsurgical lymphovenous anastomoses are usually performed using only the scrotal lymphatics excluding the testicular lymphatics drainage. We have experimented a new microsurgical technique based on lymphovenous anastomosis between the collectors of the spermatic funiculus and the veins of the pampiniform plexus, allowing the testicular lymphatic drainage. © 2007 Wiley‐Liss, Inc. Microsurgery, 2007.
An easy and safe model of kidney transplantation in rats
Authors: Karatzas Theodore , Santiago Sergio , Xanthos Theodoros , De Faria Wervinston , Gandia Carlos , Kostakis Alkiviades
Published: October 2007

A technical innovation of a novel ureter implantation technique on rat kidney allograft transplantation is described. The left kidney graft is transplanted heterotopically into the left infrarenal position, using vascular conduits from donor abdominal aorta and inferior vena cava in continuity to renal vessels, to perform arterial and venous end‐to‐side anastomoses to the recipient vessels. A new ureter implantation technique was employed by placing a purse‐string suture around the uretero‐vesical anastomosis and ligated at the end of the anastomosis to invaginate the ureter and relieve tension at its junction to the bladder. This functions as an anti‐reflux procedure, also preventing urine leakage. Bilateral native kidneys nephrectomy of the recipient was performed a week post‐transplant. This model of rat kidney transplantation was associated with high survival rate (87%) 2 weeks post‐transplant with no evidence of vascular anastomoses complications or other technical failures. The technique is easy, reliable, and can be routinely applied to other microvascular transplantation procedures. © 2007 Wiley‐Liss, Inc. Microsurgery, 2007.
Role of nitric oxide/cyclic GMP pathway in regulating spontaneous excitations in detrusor smooth muscle of the guinea‐pig bladder
Authors: Yanai Yoshimasa , Hashitani Hikaru , Hayase Masa , Sasaki Shoichi , Suzuki Hikaru , Kohri Kenjiro
Published: October 2007

Aims

The role of nitric oxide (NO)/cyclic GMP (cGMP) pathway in regulating detrusor smooth muscle (DSM) function is still to be elucidated. We have investigated the effects of NO donors and phosphodiesterase‐5 (PDE5) inhibition on spontaneous excitations in DSM.

Methods

Multibundle DSM of the guinea‐pig bladder generated spontaneous phasic contractions. The effects of sodium nitroprusside (SNP) and 3‐morpholinosydnonimine (SIN‐1), NO donors, 8‐bromo‐cyclicGMP (8‐Br‐cGMP), a cell‐permeable cGMP analog and sildenafil, a PDE5 inhibitor on these contractions were examined. The effects of these agents on spontaneous action potentials were also studied using intracellular recording technique in single‐bundle DSM.

Results

SNP and SIN‐1 enhanced spontaneous contractions in multibundle DSM and increased the frequency of spontaneous action potentials in single‐bundle DSM. These excitatory effects were not antagonized by 1H‐[1,2,4]oxadiazolo[4,3‐a]quinoxalin‐1‐one (ODQ), an inhibitor for guanylate cyclase, but were attenuated by cyclopiazonic acid (CPA), an inhibitor of sarco‐ and endoplasmic Ca ATPase (SERCA). 8‐Br‐cGMP invariably suppressed spontaneous contractility. Sildenafil inhibited spontaneous contractions in about 65% of multibundle DSM but had no effects on the remainder. In single‐bundle DSM, sildenafil had no effect on spontaneous action potentials.

Conclusions

These results suggested that NO caused an enhancement of spontaneous contractions in DSM by accelerating spontaneous action potentials through cGMP‐independent mechanisms, which may involve the Ca release from intracellular stores, whilst cGMP itself has inhibitory effects on DSM contractility. Sildenafil may indirectly suppress DSM contractility by diminishing synchronicity between functional units of DSM bundles without inhibiting excitability of DSM themselves. Neurourol. Urodynam. 27:446–453, 2008. © 2007 Wiley‐Liss, Inc.
Amide proton transfer imaging of 9L gliosarcoma and human glioblastoma xenografts
Authors: Salhotra Amandeep , Lal Bachchu , Laterra John , Sun Phillip Zhe , van Zijl Peter C. M. , Zhou Jinyuan
Published: October 2007

Amide proton transfer (APT) imaging is a variant of magnetization transfer (MT) imaging, in which the contrast is determined by a change in water intensity due to chemical exchange with saturated amide protons of endogenous mobile proteins and peptides. In this study, eight Fisher 344 rats implanted with 9L gliosarcoma cells and six nude rats implanted with human glioblastoma cells were imaged at 4.7 T. There were increased signal intensities in tumors in the APT‐weighted images. The contrast of APT imaging between the tumor and contralateral brain tissue was about 3.9% in water intensity (1.49 ± 0.66% vs −2.36 ± 0.19%) for the more uniformly hypercellular 9L brain tumors, and it was reduced to 1.6% (−1.18 ± 0.60% vs −2.77 ± 0.42%) for the human glioblastoma xenografts that contained hypocellular zones of necrosis. The preliminary results show that the APT technique at the protein level may provide a unique MRI contrast for the characterization of brain tumors. Copyright © 2007 John Wiley & Sons, Ltd.
Plumbagin recovery from field specimens of Drosophyllum lusitanicum (L.) link
Authors: Grevenstuk Tomás , Gonçalves Sandra , Nogueira José M. F. , Romano Anabela
Published: October 2007

The naphthoquinone plumbagin has a broad spectrum of biological activities. The aim of this study was to investigate the efficiency of two extraction methods (Soxhlet and ultrasound‐assisted extraction) and three solvents (methanol, chloroform and hexane) to recover plumbagin from fresh and dried tissues of field specimens of Drosophyllum lusitanicum (L.) Link. The highest extraction yields were obtained with methanol as solvent and using fresh plant material. The obtained extracts were analysed by gas chromatography with mass spectrometric detection and plumbagin was the major compound present. Plumbagin was quantified in the extracts using the external standard methodology. The results obtained showed that the best recoveries of plumbagin were attained using fresh plant material and there were no significant differences between Soxhlet and ultrasound‐assisted extraction. Moreover, hexane proved to be the more appropriate solvent for the extraction of plumbagin, providing high recoveries and the most concentrated extracts, yielding 2.42 mg of plumbagin per gram of plant material with the highest degree of purity. This method is a simple and efficient one to extract large amounts of plumbagin from D. lusitanicum field specimens. Copyright © 2007 John Wiley & Sons, Ltd.
Separation and free radical‐scavenging activity of major curcuminoids of Curcuma longa using HPTLC‐DPPH method
Authors: Pozharitskaya Olga N. , Ivanova Svetlana A. , Shikov Alexander N. , Makarov Valery G.
Published: October 2007

A direct HPTLC assay was developed for the determination of total curcuminoids and three individual curcuminoids, curcumin, demethoxycurcumin and bisdemethoxycurcumin. In addition, a new procedure was developed to separate and quantitative the free radical‐scavenging activity of individual compounds from the rhizome of Curcuma longa L. (Zingiberaceae) based on the combination of HPTLC with a diode array detector (DAD) and post chromatographic DPPH• radical derivatisation. It was established that both individual curcuminoids and the extract of C. longa were capable of scavenging DPPH• radicals. From the estimated ID50 values, it can be seen that the order of activity was curcumin > demethoxycurcumin > bisdemethoxycurcumin >> ascorbic acid. However, the ID50 values of curcuminoids were not significantly different. The data indicates the presence of a synergistic mechanism of antiradical activity of curcuminoids. Copyright © 2007 John Wiley & Sons, Ltd.
Loss of Nkx3.1 expression in the transgenic adenocarcinoma of mouse prostate model
Authors: Bethel Carlise R. , Bieberich Charles J.
Published: October 2007

BACKGROUND

The transgenic adenocarcinoma of mouse prostate (TRAMP) model has been extensively characterized at the histological and molecular levels, and has been shown to mimic significant features of human prostate cancer. However, the status of Nkx3.1 expression in the TRAMP model has not been elucidated.

METHODS

Immunohistochemical analyses were performed using dorsal, lateral, and ventral prostate (VP) lobes from ages 6 to 30 weeks. Quantitative RT‐PCR analyses were performed to determine relative mRNA expression.

RESULTS

Heterogeneous loss of Nkx3.1 was observed in hyperplastic lesions of the ventral, dorsal, and lateral lobes. At 6 weeks of age, the ventral lobe displayed profound loss of Nkx3.1. Diminished Nkx3.1 protein was observed in well‐ to moderately‐differentiated cancer lesions of all lobes. Poorly differentiated (PD) tumors stained negatively for Nkx3.1. Quantitative RT‐PCR analyses revealed the presence of Nkx3.1 mRNA in each lobe at all ages, albeit reduced to variable levels.

CONCLUSIONS

These data suggest that disease progression in the TRAMP model may be driven by loss of function of Nkx3.1, in addition to p53 and Rb. Lobe‐specific disease progression in the TRAMP model correlates with the reduction of Nkx3.1 protein. Regulation of Nkx3.1 expression during tumorigenesis appears to occur by post‐transcriptional and post‐translational mechanisms. Prostate 67: 1740–1750, 2007. © 2007 Wiley‐Liss, Inc.
Downregulation of several fibulin genes in prostate cancer
Authors: Wlazlinski Agnes , Engers Rainer , Hoffmann Michèle J. , Hader Christiane , Jung Volker , Müller Mirko , Schulz Wolfgang A.
Published: October 2007

BACKGROUND

Fibulins, encoded by FBLN genes, are extracellular matrix proteins influencing cell adhesion and migration. Altered expression of fibulins is associated with progression of several cancer types, but has not been studied in prostate cancer.

METHODS

Expression of FBLN1 (major splice forms C and D), FBLN4, FBLN5, SPOCK1, and TENC was compared between 47 prostate cancer samples and 13 benign prostatic tissues by quantitative RT‐PCR. Fibulin‐1 and fibulin‐5 expression was studied by immunohistochemistry. Effects of androgens and the DNA methylation inhibitor 5‐aza‐2′‐deoxycytidine on fibulin expression were investigated in different prostate cancer cell lines.

RESULTS

Our recent microarray analysis suggested downregulation of three fibulins, FBLN1, FBLN4, and FBLN5, in prostate cancer, while two further ECM genes, SPOCK1 (testican) and TENC (tenascin C), appeared upregulated or unchanged. These observations were corroborated by quantitative RT‐PCR. Accordingly, FBLN1 and FBLN4 were weakly expressed in carcinoma lines compared to normal prostate epithelial cells (PrECs). Only FBLN4 was induced by 5‐aza‐2′‐deoxycytidine, but its promoter was unmethylated. Androgen did not affect expression of FBLN genes. The FBLN1C and FBLN1D splice forms were coordinately expressed. Fibulin‐1 protein was weakly detectable in benign PrECs, but tended to accumulate in cancer cells. Fibulin‐5 was predominantly located in the stroma with a strong gradient from the periurethral to the peripheral zone, and lost in cancers.

CONCLUSIONS

Three FBLN genes are significantly downregulated in prostate cancer, whereas SPOCK1 is often upregulated. FBLN5 downregulation fits its postulated anticancerous function, whereas FBLN1 and FBLN4 behave different than in certain other cancers. Prostate 67: 1770–1780, 2007. © 2007 Wiley‐Liss, Inc.
Electronic and optical properties of SiC polytypes using a transferable semi‐empirical tight‐binding model
Authors: Laref A. , Laref S.
Published: October 2007

The semi‐empirical tight‐binding (TB) method within the sp3s* basis has been used to investigate the electronic structure and optical properties of silicon carbide (SiC) polytypes. A TB model for the electronic structure calculations of the (4H, 6H and 8H) SiC polytypes is presented. The procedure involves the construction of the TB Hamiltonian of the (4H, 6H and 8H) SiC polytypes from the wurtzite one. The set of TB parameters is transferable to all hexagonal structures, which overcomes the need for extensive experimental data. The band structures for different SiC polytypes are used to determine the electron effective masses. The results are shown to be consistent with available experimental data and other theoretical calculations. Furthermore, the joint densities of states are calculated. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
New general solutions of plane elasticity of one‐dimensional quasicrystals
Authors: Gao Yang , Xu Bai‐Xiang , Zhao Bao‐Sheng , Chang Tian‐Chun
Published: October 2007

A theory of general solutions of plane problems is developed for the coupled equations of plane elasticity of one‐dimensional quasicrystals. By introducing a displacement function, very large numbers of complicated equations of the in‐plane problem are simplified to a sixth‐order partial differential governing equation, and then three general solutions are presented through an operator method. Since the displacement function is required to satisfy the sixth‐order governing equation, it is still difficult to obtain rigorous analytic solutions from the higher‐order equation directly and is not applicable in most cases. Therefore, a decomposition and superposition procedure is employed to replace the higher‐order displacement function with three second‐order displacement functions, and accordingly the general solutions are simplified in terms of these functions. In consideration of different cases of three characteristic roots, the general solutions involve three cases, but all are in simple forms that are conveniently applied. Furthermore, it is worth noting that the general solutions obtained here are complete in x3‐convex domains. To illustrate the application of the general solutions obtained, the closed form solutions are obtained for wedge problems subjected to point phonon force and phason force at the apex. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Low‐temperature electrical resistivity of cupric telluride (CuTe) thin films
Authors: Neyvasagam K. , Soundararajan N. , Ajaysoni  , Okram G. S. , Ganesan V.
Published: October 2007

Thin films of cupric telluride (CuTe) of thickness from 50 to 200 nm have been prepared using a thermal evaporation technique onto well‐cleaned glass substrates kept at 300 K under a vacuum better than 2 × 10–5 mbar. After annealing the deposited films at 375 K for an hour, the resistivity of these films and that of bulk CuTe were measured using the four‐probe technique as a function of temperature from 80 to 310 K. It is found that the bulk sample of CuTe exhibits metallic behaviour and the thin films show semiconducting be‐ haviour. Activation energies of the films have been evaluated and are in the range 0.05 and 0.15 eV. The metallic behaviour of bulk CuTe down to 4 K indicates that the variable range hopping mechanism is absent in CuTe at least down to liquid helium temperature. X‐ray diffraction analysis confirmed the composition and polycrystalline nature of the CuTe films. The grain size of CuTe thin films, estimated from atomic force microscopy measurements, is around 40 nm. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A method for applying biaxial stress to solids
Authors: Trzeciakowski Witold , Strzeszewski Jan , Gębicki Wojciech , Thebaud Jean‐Marc
Published: October 2007

Large deformations of materials are achieved by applying gas pressure to thin circular plates. The deflections of the plates are measured using a laser profilometer and the strain in the centre of the plates is determined from the radius of curvature and verified by Raman scattering. The results for Si(100), Si(111) and GaAs(111) are compared with the classical theory for thin plates. The relationship between the applied pressure and the strain in the centre of the plates is simple in the case when the deflection is less than the thickness. For deflections comparable to or exceeding the thickness it is best to perform the measurements on both sides of the plate and look at the differences between them. The method should be useful for determining electron or phonon deformation potentials or for studying biaxial strain effects in one sample. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical properties of one‐dimensional graphene polymers: the case of polyphenanthrene
Authors: Prezzi D. , Varsano D. , Ruini A. , Marini A. , Molinari E.
Published: October 2007

We investigate from first principles the effect of many‐body corrections on the optoelectronic properties of polyphenanthrene (PPh), a prototype system for carbon‐based ladder polymers and 1D nanographenes with cis ‐polyene edges. We show that the inclusion of many‐body effects is essential to correctly describe both quasiparticle bandstructure and optical response. Consistently with the reduced dimensionality of the system, the inclusion of electron–hole interaction leads to strongly bound excitons which dominate the spectra. A complete characterization of the low‐energy excitonic states is carried out, together with their optical activity. In particular, we find a dark exciton below the first optically active one, which is expected to crucially affect the luminescence efficiency. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Minireview of Available Skin Sensitization (Q)SARs/Expert Systems
Authors: Patlewicz Grace , Aptula Aynur O. , Roberts David W. , Uriarte Eugenio
Published: October 2007

This minireview describes the state‐of‐the‐art of available (Q)SARs/expert systems for skin sensitization and evaluates their utility for potential regulatory use. It is one of a series of minireviews in this journal and is based on an in‐depth review performed by the European Chemicals Bureau (ECB) of the European Commission's Joint Research Centre (JRC) in support of the development of technical guidance for the implementation of the Registration, Evaluation, and Authorization of CHemicals (REACH) legislation. Most existing models fall into one of two main categories: either they are local in nature, usually specific to a chemical class or reaction chemical mechanism or else they are global in form, derived empirically using statistical methods. Some global QSARs have been recently characterized in accordance with the OECD validation principles and shown to be of limited use for regulatory applications. These have been evaluated in more detail elsewhere. Expert systems capable of predicting skin sensitization are discussed briefly. The strong mechanistic understanding of skin sensitization has facilitated the development of relative alkylation index (RAI) models. The RAI approach, relying on reactivity and hydrophobicity as the key parameters, actually appears to be the most promising means of deriving robust and mechanistically interpretable models which can be applied in a regulatory context. These are now referred to as Quantitative Mechanistic Models (QMM). Whilst hydrophobicity is conveniently modelled using log P, reactivity is often not easily determined from chemical structure. Initiatives are in progress to generate the necessary reactivity data for reactions relevant to skin sensitization but more resources are still required. A strategy of how information from using the RAI approach can be used in the evaluation of skin sensitization potential is described. This is the subject of on‐going and future work.
DFT‐Based QSAR Study of Valproic Acid and its Derivatives
Authors: Hashemianzadeh Majid , Safarpour Mohammad Ali , Gholamjani‐Moghaddam Kiana , Mehdipour Ahmad Reza
Published: October 2007

The usefulness of the quantum chemical descriptors, calculated at the level of the DFT theory using 6‐31G (d) basis set for QSAR study of antiepileptic drugs was examined. A dataset containing 25 valproic acid derivatives with known activity was used. Three types of molecular descriptors including AIM, chemical and quantum chemical was used to derive a quantitative relationship between the antiepileptic activity and structural properties. Multiple linear regressions were employed to model the relationships between molecular descriptors and biological activity of molecules using stepwise method and genetic algorithm as variable selection tools. A multi‐parametric equation containing three descriptors with good statistical qualities was obtained by Multiple Linear Regression (MLR) using stepwise method. Also, GA‐MLR regression was used to model the structure–activity relationships more accurately. The results showed that the results obtained by GA‐MLR are similar to MLR.
Quantum adiabatic switching route to the impurity modulated states of 2‐D quantum dots with different switching functions
Authors: Hazra Ram Kuntal , Ghosh Manas , Bhattacharyya S. P.
Published: October 2007

A time‐dependent quantum adiabatic switching algorithm is exploited to determine the eigenstates of 2‐D quantum dots perturbed by a repulsive scatterer. Several forms of switching functions are explored and optimal forms are suggested. The switching paths are compared for a number of states, using overlap, information entropy and energy as descriptors for possible identification of the optimal switching function. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Ab initio interpretation of Hund's rule for the methylene molecule: Variational optimization of its molecular geometries and energy component analysis
Authors: Maruyama Youhei , Hongo Kenta , Tachikawa Masanori , Kawazoe Yoshiyuki , Yasuhara Hiroshi
Published: October 2007

Hund's spin‐multiplicity rule for the ground state of the methylene molecule CH2 is interpreted by Hartree‐Fock (HF) and multi‐reference configuration interaction (MRCI) methods. The stabilization of the triplet ground state ($\tilde{X}$3B1) relative to the second singlet excited state ($\tilde{b}$1B1) is ascribed to the greater electron‐nucleus attraction energy that is gained at the cost of increasing the electron‐electron repulsion energy and with the aid of a reduction in the nucleus‐nucleus repulsion energy. The highest spin‐multiplicity in the ground state of CH2 is accompanied by a set of three characteristic features, i.e., elongation of the internuclear distances, reduction in the bond angle, and contraction of the valence electron density distribution around the nuclei involving expansion of the core electron density distribution. The present calculations fulfill the virial theorem to an accuracy of −V/T = 2.000 for both HF and MRCI. Accordingly, the molecular geometries are optimized for each of the two states. The inclusion of correlation by MRCI method reduces the energy splitting between the two states by about 14%. The energy splitting is analyzed by the correlational virial theorem 2Tc + Vc = 0 to make a clear interpretation of the correlation effect.© 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
The mitral gap at 11 + 0 to 13 + 6 weeks: marker of trisomy 21 or artifact?
Authors: Maiz N. , Dagklis T. , Huggon I. , Allan L. , Nicolaides K. H.
Published: October 2007

Objectives

To investigate the possible association between a particular pulsed Doppler waveform pattern, mitral gap, and trisomy 21 at 11 + 0 to 13 + 6 weeks.

Methods

We performed two studies. The first was a retrospective analysis of pulsed Doppler velocity waveforms of the mitral valve inflow, recorded during specialist fetal echocardiography in 291 chromosomally normal and 144 trisomy 21 fetuses with a nuchal translucency (NT) thickness of 3.5 mm or more. We examined each waveform in each trace to determine whether there was a gap between the E‐wave (early diastolic filling) and A‐wave (atrial contraction) in the waveform across the mitral valve. We also examined each trace that contained at least one waveform with a mitral gap and, first, noted the order of waveforms with a mitral gap relative to those without and, second, measured the A‐wave peak velocity in a representative waveform with a mitral gap and in one without. The second study was a prospective investigation in which Doppler velocity waveforms of the mitral valve inflow were assessed in 227 singleton pregnancies immediately before chorionic villus sampling.

Results

A mitral gap was observed in 16 (5.5%) of the chromosomally normal and in 25 (17.4%) of the trisomy 21 fetuses. The incidence of mitral gap was significantly associated with the presence of cardiac defects but not with thickness of NT. The median number of waveforms per recorded image was 6 (range, 3–7) and in 32 (78%) of the 41 traces with a mitral gap only one or two of the waveforms was abnormal. The abnormal waveforms were in the middle or at the end of the trace in 95% of cases and had a lower mean A‐wave peak velocity than did the normal waveforms (mean difference 3.7 cm/s; 95% CI, 0.3–7.0 cm/s; P = 0.03). In a prospective study of 10 normal fetuses we could produce a mitral gap deliberately by moving the sample volume out of the center of flow in the atrioventricular valve. In the prospective study of 227 pregnancies undergoing chorionic villus sampling a mitral gap was observed in 26/197 (13.2%) in which the fetal karyotype was subsequently found to be normal, 4/20 (20%) with trisomy 21 and 1/10 with other chromosomal defects.

Conclusions

At 11 + 0 to 13 + 6 weeks, a mitral gap may be more common in fetuses with trisomy 21 than in fetuses with a normal karyotype. However, it is possible that a mitral gap does not reflect an underlying hemodynamic abnormality, but is rather the result of suboptimal positioning of the Doppler sample volume as the fetus moves during acquisition. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Assisted passive snake-like robots: conception and dynamic modeling using Gibbs–Appell method
Authors: Vossoughi Gholamreza , Pendar Hodjat , Heidari Zoya , Mohammadi Saman
Published: October 2007

In this paper, we present a novel structure of a snake-like robot. This structure enables passive locomotion in snake-like robots. Dynamic equations are obtained for motion in a horizontal plane, using Gibbs–Appell method. Kinematic model of the robot include numerous nonholonomic constraints, which can be omitted at the beginning by choosing proper coordinates to describe the model in Gibbs–Appell framework. In such a case, dynamic equations will be significantly simplified, resulting in considerable reduction of simulation time. Simulation results show that, by proper selection of initial conditions, joint angles operate in a limit cycle and robot can locomote steadily on a passive trajectory. It can be seen that the passive trajectory is approximately a Serpenoid curve.
Process Design and Optimization of Novel Wheat‐Based Continuous Bioethanol Production System
Authors: Arifeen Najmul , Wang Ruohang , Kookos Ioannis K. , Webb Colin , Koutinas Apostolis A.
Published: October 2007

A novel design of a wheat‐based biorefinery for bioethanol production, including wheat milling, gluten extraction as byproduct, fungal submerged fermentation for enzyme production, starch hydrolysis, fungal biomass autolysis for nutrient regeneration, yeast fermentation with recycling integrated with a pervaporation membrane for ethanol concentration, and fuel‐grade ethanol purification by pressure swing distillation (PSD), was optimized in continuous mode using the equation‐based software General Algebraic Modelling System (GAMS). The novel wheat biorefining strategy could result in a production cost within the range of $0.96–0.50 gal−1 ethanol ($0.25–0.13 L−1 ethanol) when the production capacity of the plant is within the range of 10–33.5 million gal y−1 (37.85–126.8 million L y−1). The production of value‐added byproducts (e.g., bran‐rich pearlings, gluten, pure yeast cells) was identified as a crucial factor for improving the economics of fuel ethanol production from wheat. Integration of yeast fermentation with pervaporation membrane could result in the concentration of ethanol in the fermentation outlet stream (up to 40 mol %). The application of a PSD system that consisted of a low‐pressure and a high‐pressure column and employing heat integration between the high‐ and low‐pressure columns resulted in reduced operating cost (up to 44%) for fuel‐grade ethanol production.
Observations of a noctilucent cloud above Logan, Utah (41.7°N, 111.8°W) in 1995
Authors: Herron Joshua P. , Wickwar Vincent B. , Espy Patrick J. , Meriwether John W.
Published: October 2007

A Rayleigh‐scatter lidar has been operated at the Atmospheric Lidar Observatory (ALO) on the Utah State University (USU) campus (41.7°N, 111.8°W) since August 1993. During the morning of 22 June 1995, lidar returns from a noctilucent cloud (NLC) were observed for approximately 1 hr, well away from the twilight periods when NLCs are visible. This detection of an NLC at this latitude shows that the first reported sighting, in 1999 (Wickwar et al., 2002), was not a unique occurrence. This 1995 observation differs from the 1999 one in that temperatures could be deduced. Near the 83‐km NLC altitude the temperatures were found to be up to ∼23 K cooler than the 11‐year June climatology for ALO. This analysis shows that these cool temperatures arose, not because the whole profile was cooler, but because of a major temperature oscillation or wave with a 22‐km vertical wavelength and a ∼0.9 km/hr downward phase speed. This large‐amplitude wave has many of the characteristics of the diurnal tide. However, the amplitude would have to be enhanced considerably. These lidar observations were supplemented by OH rotational temperature observations from approximately 87 km. These NLC observations equatorward of 50° have been suggested to be significant harbingers of global change. However, if that were the case, the mechanism is more complicated than a simple overall cooling or an increase in water vapor. Accordingly, we propose enhanced generation of gravity waves that would interact with the diurnal tide to produce a large‐amplitude wave, the cold phase of which would give rise to low enough temperatures to produce the NLC. The gravity wave source might be orographic in the Mountain West or convective far to the east or south.
Assessment of the performance of ECC‐ozonesondes under quasi‐flight conditions in the environmental simulation chamber: Insights from the Juelich Ozone Sonde Intercomparison Experiment (JOSIE)
Authors: Smit Herman G. J. , Straeter Wolfgang , Johnson Bryan J. , Oltmans Samuel J. , Davies Jonathan , Tarasick David W. , Hoegger Bruno , Stubi Rene , Schmidlin F. J. , Northam T. , Thompson Anne M. , Witte Jacquelyn C. , Boyd Ian , Posny Françoise
Published: October 2007

Since 1996, quality assurance experiments of electrochemical concentration cell (ECC) ozonesondes of two different model types (SPC‐6A and ENSCI‐Z) have been conducted in the environmental simulation facility at the Research Centre Juelich within the framework of the Juelich Ozone Sonde Intercomparison Experiment (JOSIE). The experiments have shown that the performance characteristics of the two ECC‐sonde types can be significantly different, even when operated under the same conditions. Particularly above 20 km the ENSCI‐Z sonde tends to measure 5–10% more ozone than the SPC‐6A sonde. Below 20 km the differences are 5% or less, but appear to show some differences with year of manufacture. There is a significant difference in the ozone readings when sondes of the same type are operated with different cathode sensing solutions. Testing the most commonly used sensing solutions showed that for each ECC‐manufacturer type the use of 1.0% KI and full buffer gives 5% larger ozone values compared with the use of 0.5% KI and half buffer, and as much as 10% larger values compared with 2.0% KI and no buffer. For ozone sounding stations performing long term measurements this means that changing the sensing solution type or ECC‐sonde type can easily introduce a change of ±5% or more in their records, affecting determination of ozone trends. Standardization of operating procedures for ECC‐sondes yields a precision better than ±(3–5)% and an accuracy of about ±(5–10)% up to 30 km altitude.
Geological consequences of super‐sized Earths
Authors: O'Neill C. , Lenardic A.
Published: October 2007

The discovery of terrestrial‐scale extrasolar planets, and their calculated abundance in the galaxy, has prompted speculation on their surface conditions and thermal structure. Both are dependent on the tectonic regime of a planet, which is itself a function of the balance between driving forces, and the resistive strength of the lithosphere. Here we use mantle convection simulations to show that simply increasing planetary radius acts to decrease the ratio of driving to resisting stresses, and thus super‐sized Earths are likely to be in an episodic or stagnant lid regime. This effect is robust when associated increases in gravity are included, as the more dominant effect is increased fault strength rather than greater buoyancy forces. The thermo‐tectonic evolution of large terrestrial planets is more complex than often assumed, and this has implications for the surface and conditions habitability of such worlds.
Orbital and CO2 forcing of late Paleozoic continental ice sheets
Authors: Horton Daniel E. , Poulsen Christopher J. , Pollard David
Published: October 2007

Contrasting views of the size, duration, and history of the Gondwanan continental ice sheets have been proposed from late Paleozoic glaciological and sedimentological evidence. To evaluate these differing views, a coupled ice sheet‐climate model is used to simulate continental ice sheets under a wide range of late Paleozoic orbital and pCO2 conditions. The model experiments indicate that orbital variations at pCO2 concentrations below 2X pre‐industrial atmospheric levels (PAL; 280 ppm) produce large changes in late Paleozoic ice volume (∼1.3 × 108 km3) and sea level (∼20 to 245 m). Between 2 and 8X PAL Gondwana continental ice is simulated only under the most extreme Southern Hemisphere cold summer orbit, but still produces significant ice volumes (∼8–12 × 107 km3). Our results highlight the important role of atmospheric CO2 in determining the distribution, volume, and stability of late Paleozoic ice sheets, factors that ultimately impacted sea level, cyclothem deposition, and global climate, and reconcile disparate views of the Late Paleozoic Ice Age.
Detecting tsunami genesis and scales directly from coastal GPS stations
Authors: Song Y. Tony
Published: October 2007

Different from the conventional approach to tsunami warnings that rely on earthquake magnitude estimates, we have found that coastal GPS stations are able to detect continental slope displacements of faulting due to big earthquakes, and that the detected seafloor displacements are able to determine tsunami source energy and scales instantaneously. This method has successfully replicated three historical tsunamis caused by the 2004 Sumatra earthquake, the 2005 Nias earthquake, and the 1964 Alaska earthquake, respectively, and has been compared favorably with the conventional seismic solutions that usually take hours or days to get through inverting seismographs. Because many coastal GPS stations are already in operation for measuring ground motions in real time as often as once every few seconds, this study suggests a practical way of identifying tsunamigenic earthquakes for early warnings and reducing false alarms.