bluuebunny/crossref_metadata_2025_split huggingface dataset:
Testing AdS/CFT at string loops
Authors: Grignani G. , Orselli M. , Ramadanovic B. , Semenoff G.W. , Young D. 
Published: May 2007

AbstractThis article is based on the result obtained in hep‐th/0508126 and hep‐th/0605080 where we use the IIB light‐cone string field theory proposed by Dobashi and Yoneya to compute the one string‐loop correction to the energies of two impurity BMN states. We found that the result agrees with the gauge theory prediction at leading order – one‐loop in Yang‐Mills theory – and that is quite close also at second order in Yang‐Mills loops. We furthermore find that the half integer powers in the t'Hooft coupling are absent up to the 7/2 power.
Progress in D‐brane model building
Authors: Marchesano F. 
Published: May 2007

AbstractThe state of the art in D‐brane model building is briefly reviewed, focusing on recent achievements in the construction of D = 4 𝒩 = 1 type II string vacua with semi‐realistic gauge sectors. Such progress relies on a better understanding of the spectrum of BPS D‐branes, the effective field theory obtained from them and the explicit construction of vacua. We first consider D‐branes in standard Calabi‐Yau compactifications, and then the more involved case of compactifications with fluxes. We discuss how the non‐trivial interplay between D‐branes and fluxes modifies the previous model‐building rules, as well as provides new possibilities to connect string theory to particle physics.
Application of extended Hazop and event‐tree analysis for investigating operational failures and safety optimization of distillation column unit
Authors: Ramzan Naveed , Compart Fred , Witt Werner 
Published: May 2007

AbstractProcess safety has a high priority in the chemical industry. And the distillation is the most widely used unit operation in the chemical‐processing industries. The use of dynamic simulation for safety‐related studies for a distillation column has great significance for the study of operational failures. In this article, a systematic framework based on Extended Hazop and Event‐tree analysis is applied to a distillation column unit of a chemical plant. Over pressuring of column is studied and different safety system alternatives are generated and evaluated using Event‐tree analysis. This article describes the details of an effective method used for a distillation column but it can also be used for other hazardous unit operations. © 2007 American Institute of Chemical Engineers Process Saf Prog 2007
Time‐resolved nanosecond sub‐micron resolution thermal analysis of high‐power AlGaN/GaN HFETs
Authors: Kuball M. , Riedel G. J. , Pomeroy J. W. , Sarua A. , Uren M. J. , Martin T. , Hilton K. P. , Wallis D. J. 
Published: May 2007

AbstractA novel time‐resolved micro‐Raman thermography technique has been developed to measure the active region temperature in AlGaN/GaN electronic devices, achieving a temporal and spatial resolution of 200 ns and 0.5–0.7 μm, respectively. AlGaN/GaN heterostructure field effect transistors (HFETs) grown on SiC and sapphire substrates are compared. Rapid temperature changes within 200 ns of current changes are followed by a slower change in device temperature. For a device on a SiC substrate an approximate temperature plateau is reached within 1–2 μs after switching the device on or off, illustrating its fast thermal response. This is in contrast to the slower time constant of devices on sapphire substrates where μs‐separated electrical pulses do not allow the devices to cool to room temperature between the electrical pulses. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High‐sensitivity UV phototransistor with GaN/AlGaN/GaN gate epi‐structure
Authors: Okada Masaya , Matsuura Kazuaki , Ao Jin‐Ping , Ohno Yasuo , Kawai Hiroji 
Published: May 2007

AbstractA highly sensitive UV phototransistor was developed using AlGaN/GaN heterojunction field effect transistor (HFET) technology. The phototransistor consisted of a thin undoped GaN layer added on top of a conventional AlGaN/GaN HFET structure. In such a structure, holes generated in the surface i‐GaN layer are accumulated at the GaN/AlGaN interface, and they modulate the electrons in the FET channel. Due to this charge modulation effect, high photocurrent can be obtained. In the structure under study, hole life time was so long that a hole‐evacuating refresh operation was required for fast response and linear sensitivity. When irradiated with UV light of 360 nm, a device with 6 × 10–4 mm2 active area produced two hundred times higher photocurrent than a commercial Si UV diode with a much larger area. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nitride intersubband devices: prospects and recent developments
Authors: Julien F. H. , Tchernycheva M. , Nevou L. , Doyennette L. , Colombelli R. , Warde E. , Guillot F. , Monroy E. 
Published: May 2007

AbstractThis paper reports on GaN/AlN light‐emitting devices relying on intersubband transitions. All samples have been grown by molecular beam epitaxy. We first present a systematic investigation of single or coupled GaN/AlN quantum wells grown by MBE. We then present the recent observation of strong ISB resonant enhancement of the second‐harmonic generation of 1μm radiation. We finally report on the first observation of ISB luminescence in GaN QWs, which opens new prospects for the realization of nitride unipolar lasers based on current injection or optical pumping. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optimization of the luminescence emission in nanocrystalline SiGe/SiO2 multilayers
Authors: Rodríguez A. , Ortiz M. I. , Sangrador J. , Rodríguez T. , Avella M. , Prieto A. C. , Jiménez J. , Kling A. , Ballesteros C. 
Published: May 2007

AbstractLuminescent multilayers of SiGe nanocrystals embedded in an oxide matrix have been fabricated by Low Pressure Chemical Vapour Deposition of SiGe and SiO2 in a single run followed by a Rapid Thermal Annealing treatment to crystallize the SiGe nanoparticles. Structural parameters like the diameter of the nanoparticles and the oxide interlayer thickness, as well as the annealing conditions have been investigated in order to get the maximum intensity of the luminescence emission. Structures with small nanoparticles (3–4.5 nm) separated by thick oxide barriers (≈35 nm) annealed at 900 °C for 60 s yield the maximum intensity as a result of a compromise between the appropriate crystallization of the small nanoparticles and a reduced degradation of their composition by Ge diffusion. An additional treatment at 450 °C in forming gas for dangling‐bond passivation increases the intensity of the luminescence by 25%. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Application of the MTD‐PLS method to heterocyclic dye–cellulose interactions
Authors: Kurunczi Ludovic , Funar‐Timofei Simona , Bora Alina , Seclaman Edward 
Published: May 2007

AbstractThe minimal topologic difference method in a projection in latent structures variant procedure was applied to a series of heterocyclic monoazo dyes of the type: RC6H4N = NY (R = benzothiazole, benzimidazole, N‐containing aromatic pentacycles; Y = γ acid, H acid, chromotropic acid, R acid). A statistically excellent model was obtained: RX2 = 0.625, RY2 = 0.940, Q2 = 0.822. The analysis of this model reveals the nature of dye–fiber interactions, which determine the dye affinity. Hydrophobic character in the R group and H‐bond donor groups in a specific Y substitution position augment the dye affinity for cellulose. An increase of the polar nature of atoms in R depletes the affinity. Also some lateral substituents belonging to the Y coupling components suffer steric hindrance, and their presence is detrimental for the affinity. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
A quantum‐chemical study of n‐butane and of butane cation radical
Authors: Garifzianova Guzel G. , Tsyshevskii Roman V. , Shamov Alexander G. , Khrapkovskii Grigorii M. 
Published: May 2007

AbstractA comparative computational study of the n‐butane and the butane cation radical is made by using the B3LYP density functional method with standard basis set 6‐31G(d). The conventional transition state theory was used to calculate the enthalpies of butane and its cation radical and the dissociation energies of the CC bond. Basis tendencies in parameter changes of the geometric and electronic structures of molecules and transition states, the enthalpies of formation, and the dissociation energies are analyzed. Computational results are compared with experimental data where possible. On the whole, the B3LYP method exhibits good agreement with experiment. Distinct values of barriers of the similar reactions of molecules and cation radicals are essential. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Investigation of the nanoscale self‐assembly of donor‐σ‐acceptor molecules
Authors: Sumpter Bobby G. , Meunier Vincent , Vázquez‐Mayagoitia Álvaro , Castellano Ronald K. 
Published: May 2007

AbstractElectronic structure calculations are used to explore the nature of the interactions that lead to the self‐assembly of a new class of functionalized donor‐σ‐acceptor molecules, 1‐aza‐adamantanetriones (AATs), and the consequences of molecular structure on the resulting supramolecular systems. The results show how the self‐assembly process originates from the saturated core of the molecules that underlies their shape, conformational preferences, and dipole‐directed one‐dimensional assembly. The solvation properties of the monomers are explored and 1H NMR chemical shift values are determined and compared to experimental trends. A theoretical understanding of this class of supramolecular structures coupled with their molecular‐level tunability introduces the possibility to design novel functional materials for specific electronic and optoelectronic applications. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Douglas P. Taylor
Authors: Taylor Douglas P. 
Published: May 2007

AbstractThis article profiles my life and career highlights. I am an engineer who specializes in the mitigation of shock and vibration for structures of all types—from buildings and bridges to aircraft, naval vessels, and spacecraft. It is the story of how I entered the profession during the Cold War period and went on from there to invent many damping concepts. In some cases, names and project highlights have been omitted for security reasons. This is the nature of some of my work. Copyright © 2007 John Wiley & Sons, Ltd.
Ronald L. Mayes
Authors: Mayes Ronald L. 
Published: May 2007

AbstractThis paper presents a summary of the career of the author associated with his selection as the 2006 Structural Engineer of the Year. It spans his days as a student at the University of Auckland, New Zealand, as a research engineer at the University of California, Berkeley, and his consulting experience with Computech Engineering Services and SGH Inc. It includes his 6‐year tenure as the Technical and Executive Director of the Applied Technology Council and his 17 years with Dynamic Isolation Systems. Copyright © 2007 John Wiley & Sons, Ltd.
Responses of Daphnia magna to pulsed exposures of arsenic
Authors: Hoang Tham C. , Gallagher Jeffrey S. , Klaine Stephen J. 
Published: May 2007

AbstractResearch on the toxicity of arsenic has focused on sublethal effects that do not provide sufficient information for risk estimation. While most studies have focused on organism response to constant arsenic exposures, organisms in nature are exposed to fluctuating As concentrations. Consequently, results obtained from standardized bioassays with constant exposures may not adequately characterize risk to indigenous biota. This research was designed to characterize the response of Daphnia magna to fluctuating arsenic exposures during 21‐day experiments. At concentrations ≥3000 μg/L As, 21‐day pulsed exposure mortality increased as a function of exposure concentration and duration. In addition, 21‐day pulsed exposure mortality increased with increasing recovery time. Pulsed As exposure did not affect the growth of D. magna over 21 days. Twenty‐one day accumulative reproduction of D. magna was only affected by pulsed exposures of high As concentration and long durations. © 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 308–317, 2007.
Removal of estrogenic activity of 4‐tert‐octylphenol by ligninolytic enzymes from white rot fungi
Authors: Tamagawa Yuuki , Hirai Hirofumi , Kawai Shingo , Nishida Tomoaki 
Published: May 2007

Abstract4‐tert‐Octylphenol (4‐t‐OP) was treated with the white rot fungus Phanerochaete sordida YK‐624 under ligninolytic condition with low‐nitrogen and high‐carbon culture medium. 4‐t‐OP completely disappeared after 5 days of treatment and the activities of ligninolytic enzymes, laccase and manganese peroxidase (MnP), were detected during this period, thus suggesting that the disappearance of 4‐t‐OP is related to these extracellular enzymes. Therefore, 4‐t‐OP was treated with laccase and MnP prepared from white rot fungi cultures. HPLC analysis demonstrated that 4‐t‐OP completely disappeared in the reaction mixture after 1 h of treatment with either laccase or MnP. Using the yeast two‐hybrid assay system, it was also confirmed that laccase and MnP substantially removed the estrogenic activity of 4‐t‐OP after 1 and 2 h of treatment, respectively. These results strongly demonstrate that ligninolytic enzymes are effective in removing the estrogenic activity of 4‐t‐OP. © 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 281–286, 2007.
Benchmark dose approach for renal dysfunction in workers exposed to lead
Authors: Lin Tian , Tai‐yi Jin 
Published: May 2007

AbstractBenchmark dose (BMD) and the lower confidence limit on the benchmark dose (BMDL) of blood lead were estimated to explore the biologic exposure limits for renal dysfunction caused by lead. One hundred thirty‐five workers from one storage battery plant were selected as lead exposure group while 143 mechanics as the control. The relationship between the blood lead concentration and the urinary excretion of total protein (TP), β2‐microglobulin (β2‐MG), and N‐acetyl‐β‐D‐glucosaminidase (NAG) was studied. The quantal linear logistic regression model (BMDS Version 1.3.1) was used to calculate BMD and BMDL of blood lead. The results showed that the levels of NAG, β2‐MG, and TP in lead‐exposed workers were higher than those of control group and elevated along with rising length of employment. The levels of three indices for renal dysfunction increased with the elevated blood lead. The BMD and BMDL of blood lead for renal dysfunction were from 299.4 to 588.7 μg/L and from 253.4 to 402.3 μg/L, respectively. The BMDL of blood lead was ranged from high to low as TP, β2‐MG, and NAG. It is suggested that the urinary NAG activity could be a sensitive and early biomarker of renal tubular dysfunction induced by lead. When assessing renal function in workers occupationally exposed to lead, a blood lead level of 250 μg/L could serve as a warning signal. © 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 229–233, 2007.
Subacute toxicity evaluation in rats exposed to concrete and hwangto building environments
Authors: Lee Seung‐Won , Yang Young‐Su , Ahn Tai‐Hwan , Bae Chun‐Sik , Moon Chang‐Jong , Kim Sung‐Ho , Song Seung‐Yeong , Hwang Hey‐Zoo , Kim Jong‐Choon 
Published: May 2007

AbstractThis study examined the potential adverse effects of the subacute exposure of rats to concrete and hwangto building environments. Polycarbonate was used as a comparison. Groups of 10 male rats were exposed to polycarbonate, concrete, or hwangto cages for a 4‐week period in summer or winter. During the study period, the clinical signs, mortality, skin temperature, body weight, food consumption, ophthalmoscopy, urinalysis, hematology, serum biochemistry, gross findings, organ weights, and histopathology were examined. The concentration of total volatile organic compounds (VOCs), temperature, and relative humidity in the each cages were also measured. There were no exposure‐related effects in any group of the study examined in the summer. The temperature, relative humidity, and the concentration of VOCs in the cages were similar in all groups. However, in the winter study, significant differences in several parameters were detected among the groups. In the concrete group, there was an increase in the clinical signs, a reduction in the body weight gain, food intake, and liver weight, an increase in the lung weight, and an increase in the histopathological alterations in the lung and thymus. Infrared thermal analysis showed that the skin temperature of the rats in the concrete group was lower than that in the polycarbonate group. However, in the hwangto group, there was a decrease in the clinical signs and an increase in the body weight, food intake, and the weights of the heart, lung, spleen, and epididymides. Overall, the 4‐week exposure of the rats to the concrete building environment had adverse effects on the clinical signs, skin temperature, body weight, and some organs in the winter but not in the summer. On the other hand, the exposure of hwangto building environment did not have any exposure‐related adverse effects on the general health parameters and skin temperature in rats. © 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 264–274, 2007.
Copper and zinc tolerance of two tropical microalgae after copper acclimation
Authors: Johnson Hilary L. , Stauber Jenny L. , Adams Merrin S. , Jolley Dianne F. 
Published: May 2007

AbstractCurrent toxicity tests with microalgae are often criticized as being overly sensitive to metals because algae are cultured in metal‐deficient media. If such bioassays overestimate copper toxicity in surface waters, the relevance of water quality guidelines derived from these tests is questionable. In this study, the effect of acclimation to copper at environmentally relevant concentrations, on the sensitivity of the marine diatom Nitzschia closterium and the freshwater green alga Chlorella sp. to copper and zinc was examined. N. closterium was acclimated in culture medium containing 5 or 25 μg Cu L−1 for 200 days, while Chlorella sp. was acclimated in medium containing 2 μg Cu L−1 for 100 days. Changes in algal growth rates and copper and zinc tolerance were monitored using standard growth inhibition toxicity tests in minimal medium over 72 h. Neither of the two acclimated N. closterium cultures had increased zinc or copper tolerance compared with that of the nonacclimated algae, nor were there any changes in control growth rates. Similarly, no changes in copper tolerance or control growth rates were observed for the acclimated Chlorella sp. culture. This was supported by measurements of intracellular and extracellular copper which confirmed that there were no differences in copper accumulation in either acclimated or nonacclimated algae. These results suggest that these algae grown in standard culture media are generally no more sensitive than algae grown in a metal‐enriched medium. This supports the continued use of current laboratory bioassays with microalgae, as part of a suite of tests for assessing metal bioavailability, for use in ecological risk assessments and for providing data for the derivation of water quality guidelines. © 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 234–244, 2007.
8. Genital lumps and bumps: what is normal?
Authors: O'Mahony Colm 
Published: May 2007

AbstractWhen patients present with genital ‘lesions’, it is important to distinguish between normal anatomical variants, which usually require only reassurance, and other similar‐appearing conditions such as genital warts. Dr O'Mahony provides an illustrated account of some common normal genital lumps and bumps. Copyright © 2007 Wiley Interface Ltd
Prenatal three‐dimensional ultrasound: perception of sonographers, sonologists and undergraduate students
Authors: Lee S. , Pretorius D. H. , Asfoor S. , Hull A. D. , Newton R. P. , Hollenbach K. , Nelson T. R. 
Published: May 2007

AbstractObjectiveTo assess the perception of non‐pregnant sonographers, sonologists and undergraduate students on the use of three‐dimensional (3D) ultrasound technology in fetal medicine.MethodsThis was a study of two groups of non‐pregnant subjects. Group I included 520 (305 female, 215 male) medical professionals who completed a questionnaire after attending a lecture on 3D imaging. Factors such as gender, career and having children were analyzed with respect to the attendee's responses about use of 3D ultrasound for medical purposes and for reassurance. Group II included 137 (75 female, 60 male, two unknown) undergraduate students from bioengineering, psychology and physiology classes who completed a questionnaire after attending a brief presentation on two‐dimensional and 3D fetal imaging. Factors such as gender and area of educational interest were analyzed with respect to the students' responses about the use of 3D ultrasound for medical purposes and for parental–fetal attachment.ResultsIn Group I, 63% said that they would like to have a 3D ultrasound examination in the future, while 14% said that they would not. Common reasons given for wanting a 3D ultrasound exam in the future were for medical purposes (39%) or reassurance (18%). The main differences perceived between two‐dimensional (2D) and 3D ultrasound were medical advantages (65%) and parental reassurance (28%). 62.4% of Group I thought 3D technology should be in wide use in obstetric ultrasound and 73.6% thought that 3D ultrasound would reassure parents carrying normal fetuses. Gender, age and career did not have a significant influence on perception of 3D ultrasound. In Group II, the majority (91%) said they could see a remarkable difference between 2D and 3D ultrasound. 83% responded that they would like to have a 3D ultrasound examination of their own baby in the future for the following reasons: 34% for the detailed picture, 31% for increased abnormality detection, 13% for reassurance or curiosity; 8% thought it would be unnecessary or a negative experience. Concerning parental–fetal attachment, 72% thought 3D ultrasound would have a positive effect. The majority of Group II (93%) thought 3D ultrasound would be valuable and 56% thought 3D ultrasound would assist in diagnosing fetal abnormalities. There was no significant relationship between gender, age or area of interest and the perception of 3D ultrasound.ConclusionsResponses by sonographers and physicians suggest that 3D ultrasound will have a role in the future for medical indications and in reassuring patients carrying normal fetuses. Our results also suggest that undergraduate students believe that 3D ultrasound will be a valuable technique in obstetrics and that it will have a positive effect on parental–fetal attachment. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.