bluuebunny/crossref_metadata_2025 huggingface dataset:
When circuits are printed, labels can talk ‐ New nanomaterials enable low cost flexible electronics
Authors: Arning Volker , Leenen Mark A.M. , Steiger Jürgen , Anselmann Ralf
Published: April 2009

Electronics and printing are two very powerful technologies that we encounter many times on a daily basis. Both technologies are very efficient and optimized for their purpose but have distinctive limitations. Printed information is unbeatable when it comes to production efficiency and cost, but once the information has been printed it cannot be changed. Electronics on the other hand is very powerful in the handling of changing information, but the associated costs of the electronics make it often too expensive for the integration into simple day‐to‐day products. If the advantages of printing and electronics are successfully combined, a new technological field with a potential market size of several billion euros will be created. In this article, the basic principles of printing and electronics are explained and ways for the realization of electronics by printing are outlined. A short overview will be given on the material classes which are currently investigated for use in printed circuits.
Open fractures of the tibia in the pediatric population: A systematic review
Authors: Baldwin Keith D. , Babatunde Oladapo M. , Russell Huffman G. , Hosalkar Harish S.
Published: April 2009

Purpose

The management of open fractures of the tibia in a pediatric population represents a challenge to the clinician. Several case series over the course of many years have been performed describing the results of treating these injuries. It remains unclear, however, whether there is a preferred modality of treatment for these injuries, if a more severe injury confers a greater risk of infection, and if time to union is affected by Gustilo type, although trends seem to exist. The purpose of this study was to assemble the available data to determine (1) the risk of infection and time to union of various subtypes of open tibia fractures in children and (2) the changes in treatment pattern over the past three decades.

Methods

A systematic review of the available literature was performed. Frequency weighted mean union times were used to compare union times for different types of open fractures. Mantel Haentzel cumulative odds ratios were used to compare infection risk between different types of open fractures. Linear regression by year was used to determine treatment practices over time.

Results

No significant change in practice patterns was found for type I and III fractures, although type II fractures were more likely to be treated closed in the later years of the study compared to the earlier years. Type III fractures conferred a 3.5- and 2.3-fold greater odds of infection than type I and type II fractures, respectively. There was no significant difference in odds of infection between type I and II fractures. There was a significant delay in mean time to union between type I and type II fractures, and between type II and type III fractures.

Conclusions

With the exception of type II fractures, the philosophy of treatment of open fractures of the tibia has not significantly changed over the past three decades. Closed treatment or internal fixation are both viable options for type II fractures based on their relatively low incidence of infection. This study also demonstrates a strong relationship between Gustillo sub-types and odds of infection in this population. Not surprisingly, union rates are also delayed with increasing injury severity.
A novel family of hemicellulolytic α‐glucuronidase
Authors: Ryabova Olena , Vršanská Mária , Kaneko Satoshi , van Zyl Willem H. , Biely Peter
Published: April 2009

Investigation of the xylanolytic enzyme system of the xylose‐fermenting yeast Pichia stipitis resulted in the discovery of an extracellular α‐glucuronidase efficiently debranching hardwood glucuronoxylan. This activity is not exhibited by more extensively investigated α‐glucuronidases of glycoside hydrolase (GH) family 67, operating on substrates in which the uronic acid is linked to the non‐reducing xylopyranosyl residues of main chain fragments. The N‐terminus of the purified enzyme corresponded exactly to the P. stipitis gene ABN67901 coding for a protein of unknown function. BLAST search revealed the presence of similar genes in genomes of other microorganisms. These results lead to the emergence of a new family of α‐glucuronidases.
Fluorescence microscopy studies on islet amyloid polypeptide fibrillation at heterogeneous and cellular membrane interfaces and its inhibition by resveratrol
Authors: Radovan Diana , Opitz Norbert , Winter Roland
Published: April 2009

Type II diabetes mellitus (T2DM) is a disease characterized by progressive deposition of amyloid in the extracellular matrix of β‐cells. We investigated the interaction of the islet amyloid polypeptide (IAPP) with lipid model raft mixtures and INS‐1E cells using fluorescence microscopy techniques. Following preferential partitioning of IAPP into the fluid lipid phase, the membrane suffers irreversible damage and predominantly circularly‐shaped lipid‐containing IAPP amyloid is formed. Interaction studies with the pancreatic β‐cell line INS‐1E revealed that growing IAPP fibrils also incorporate substantial amounts of cellular membranes in vivo. Additionally, the inhibitory effect of the red wine compound resveratrol on IAPP fibril formation has been studied, alluding to its potential use in developing therapeutic strategies against T2DM.
Decreased activity of desaturase 5 in association with obesity and insulin resistance aggravates declining long-chainn-3 fatty acid status in Cree undergoing dietary transition
Authors: Zhou Yuan E. , Kubow Stan , Dewailly Eric , Julien Pierre , Egeland Grace M.
Published: April 2009

Emerging evidence shows that desaturase 5 (Δ5), the key regulator in the synthesis of highly unsaturated long-chain fatty acids (HUFA), is modulated by factors including adiposity, diet and insulin resistance. We explored the association of these factors in a cross-sectional study within a high-risk Cree population. Anthropometric measures and fasting blood glucose and insulin were analysed. Δ5 was estimated as the 20 : 4n-6:20 : 3n-6 ratio in erythrocyte membranes. The setting of the present study was the Mistissini community in the Cree Territory of Québec, Canada with ninety-eight female and sixty-eight male subjects aged 20–88 years. Obesity (BMI ≥ 30 kg/m2) was prevalent across age groups. Δ5 was inversely associated with BMI (Spearman's correlation coefficient (rs) − 0·175;P = 0·03) and positively associated with age (rs0·593;P < 0·0001), which was driven by age-related increases in dietary intake ofn-3 fatty acids and decreases in 20 : 3n-6. Homeostasis model assessment of insulin resistance (HOMA-IR) was significantly inversely associated with Δ5 in age-adjusted linear regression analyses in normoglycaemic individuals (β − 2·110 (se0·566);P < 0·001), whereas no association was observed among glucose-intolerant individuals (interaction termP = 0·03). In contrast, there were no significant interactions indicating differences in the slope for each of the adiposity measures in their associations with Δ5. The present study indicates that the dietary transition of reduced consumption of fish among younger Cree may compound the effects of obesity and emerging insulin resistance which, in turn, could reduce bioavailability of HUFAn-3 (through reduced Δ5 activity). Also, the study suggests that disease progression is an important consideration when evaluating correlates of Δ5 activity in observational studies.
Electoral College Winner's Advantage
Authors: Riggs Jack E. , Hobbs Gerald R. , Riggs Todd H.
Published: April 2009

Compared to the popular vote, the Electoral College magnifies the
perception of the winner's margin of victory. In this analysis, a
method of quantifying the magnitude of the advantage given to the
winner due to the Electoral College's two electoral vote add-on and
winner-take-all methodologies is presented. Using the electoral vote
distribution that was present in the 2000 U.S. presidential
election, we analyzed one million random two-candidate simulated
elections. The results show that the net effect of the Electoral
College is to give the winning candidate an average 29.45 electoral
vote advantage per election due to the winner-take-all methodology.
This winner's advantage includes an average 0.42 electoral vote
advantage given to the winner per election due to the two electoral
vote add-on.
Political Science as a Vocation
Authors: Keohane Robert O.
Published: April 2009

This lecture was presented at the University of Sheffield on October
22, 2008, inaugurating the Graduate School of Politics; and at
Oxford University on October 16, 2008. I have retained the lecture
style for this publication, only making minor changes and additions
in the text.
Entwicklung und psychometrische Kennwerte des Fragebogens zur Evaluation von Psychotherapieverläufen (FEP)
Authors: Lutz Wolfgang , Schürch Eva , Stulz Niklaus , Böhnke Jan R. , Schöttke Henning , Rogner Josef , Wiedl Karl Heinz
Published: April 2009

Zusammenfassung. Die kontinuierliche Messung des therapeutischen Fortschritts ist im Rahmen der Qualitätssicherung in Psychotherapie und Psychiatrie ein zentrales Element. In dieser Arbeit wird ein deutschsprachiges Messinstrument vorgestellt, welches sich zur Erhebung des Therapieverlaufs eignet. Das Instrument ist multidimensional, veränderungssensitiv und zusätzlich „public domain” verfügbar. Theoretisch wurden drei klinisch-therapeutische Konzeptualisierungen zentraler Veränderungsprozesse integriert: das Phasenmodell therapeutischer Veränderung, das Kreismodell interpersonaler Beziehungen sowie das Kongruenzkonzept. Anhand von lediglich 40 Items werden die Dimensionen Wohlbefinden, Beschwerden, interpersonale Beziehung und Kongruenz erhoben. Zur Validierung wurden eine ambulante Psychotherapiestichprobe (N = 184), eine nicht-klinische (N = 274) sowie eine studentische Stichprobe (N = 96) herangezogen. Die vier Dimensionen sowie ein daraus resultierender Gesamtwert psychischer Beeinträchtigung weisen gute Werte der Reliabilität auf. Das Instrument kann sowohl zur Verlaufs-, als auch zur Ergebnismessung eingesetzt werden.
„Do it again and again. And again?”
Authors: Albers Frank , Höft Stefan
Published: April 2009

Zusammenfassung. Die wiederholte Bearbeitung eines identisch oder parallel konstruierten kognitiven Fähigkeitstests führt in der Regel zu einer deutlich verbesserten Leistung. Zunächst wird ein Überblick zur bestehenden empirischen Befundlage zu Testwiederholungseffekten sowie zu möglichen Verursachungen gegeben. Als kognitionspsychologischer Anknüpfungspunkt dient hierbei Ackermans (1988) Theorie zum Fertigkeitserwerb. Danach wird in der vorgestellten Studie am Beispiel eines Tests zum räumlichen Vorstellungsvermögen (Relative Position, REP) die Auswirkung von Testwiederholungseffekten auf die Testleistung der Probanden sowie die Testreliabilität und -validität untersucht. 156 Bewerber in einem Auswahlprogramm für Nachwuchsflugzeugführer bearbeiteten insgesamt zehnmal hintereinander das jeweils fünfminütige Testverfahren. Nach der fünften Testdurchführung weisen die erzielten Zuwächse keine praktische Bedeutsamkeit mehr auf. Reliabilität und Validität des Tests werden durch die Übung nicht beeinträchtigt, sondern scheinen eher noch anzusteigen. Konsequenzen für die diagnostische Anwendung werden diskutiert.
Aerosol effects on liquid‐water path of thin stratocumulus clouds
Authors: Lee Seoung Soo , Penner Joyce E. , Saleeby Stephen M.
Published: April 2009

Thin clouds with mean liquid water path (LWP) of ∼50 g m−2 cover 27.5% of the globe and thus play an important role in Earth's radiation budget. Radiative fluxes at Earth's surface and top of atmosphere are very sensitive to the LWP variation when the LWP becomes smaller than ∼50 g m−2. This indicates that aerosol effects on thin clouds can have a substantial impact on the variation of global radiative forcing if LWP changes. This study examines the aerosol indirect effect through changes in the LWP in three cases of thin warm stratocumulus clouds with LWP < 50 g m−2. We use a cloud‐system resolving model coupled with a double‐moment representation of cloud microphysics. Intensified interactions among the cloud droplet number concentration, condensation, and dynamics at high aerosol play a critical role in the LWP responses to aerosol increases. Increased aerosols lead to increased CDNC, providing the increased surface area of droplets where water vapor condenses. This increases condensation, and thus condensational heating, to produce stronger updrafts, leading to an increased LWP with increased aerosols in two of the cases where precipitation reaches the surface. In a case with no surface precipitation, LWP decreases with increases in aerosols. In this case, most of precipitation evaporates just below the cloud base. With decreases in aerosols, precipitation increases and leads to increasing evaporation of precipitation, thereby increasing instability around the cloud base. This leads to increased updrafts, and thus condensation, from which increased LWP results.
Predicting relative permeability from water retention: A direct approach based on fractal geometry
Authors: Cihan Abdullah , Tyner John S. , Perfect Edmund
Published: April 2009

Commonly, a soil's relative permeability curve is predicted from its measured water retention curve by fitting equations that share parameters between the two curves (e.g., Brooks/Corey‐Mualem and van Genuchten‐Mualem). We present a new approach to predict relative permeability by direct application of measured soil water retention data without any fitting procedures. The new relative permeability model, derived from a probabilistic fractal approach, appears in series form as a function of suction and the incremental change in water content. This discrete approach describes the drained pore space and permeability at different suctions incorporating the effects of both pore size distribution and connectivity among water‐filled pores. We compared the new model performance predicting relative permeability to that of the van Genuchten‐Mualem (VG‐M) model for 35 paired data sets from the Unsaturated Soil hydraulic Database (UNSODA) and five other previously published data sets. At the 5% level of significance, the new method predicts relative permeabilities from the UNSODA database significantly better (mean logarithmic root‐mean‐square error, LRMSE = 0.813) than the VG‐M model (LRMSE = 1.555). Each prediction of relative permeability from the five other previously published data sets was also significantly better.
Searching for other Earth‐like planets
Authors: Showstack Randy
Published: April 2009

NASA's Kepler mission, which launched into space on 6 March, will soon begin to search for extrasolar planets, after calibration of its wide‐field charge‐coupled device camera is completed. The first planets Kepler finds could be gas giants; finding Earth analogs, assuming there are any, could take 3 or more years to discover and confirm, according to scientists involved with the mission.
Tracking seasonal signs of climate change
Authors: Showstack Randy
Published: April 2009

On 2 March, the USA National Phenology Network (USA‐NPN), a consortium of government, academic, and citizen scientists, launched a national program for volunteers to help observe the seasonal cycles of plants, including flowering, fruiting, and other seasonal events. The program will begin monitoring animals in 2010. Scientists and resource managers will use these observations to track effects of climate change on Earth's life‐support systems.
Arctic observing system report available
Authors: Showstack Randy
Published: April 2009

The newly released 2008 report of the integrated Arctic Ocean Observing System (iAOOS) offers an overview of key iAOOS projects (cruises taken, instrumentation deployed, measurements made) and describes first results, including those demonstrating the validity of an iAOOS program for the International Polar Year (IPY).
Lee Receives 2008 Hisashi Kuno Award
Authors: Rudnick Robert L. , Lee Cin‐Ty
Published: April 2009

Cin‐Ty Lee received the 2008 Hisashi Kuno Award at the 2008 AGU Fall Meeting Honors Ceremony, held 17 December 2008 in San Francisco, Calif. The award is for outstanding contributions to the fields of volcanology, geochemistry, or petrology.
Strong Receives 2008 James R. Holton Junior Scientist Award
Authors: Magnusdottir Gudrun , Strong Courtenay
Published: April 2009

Courtenay Strong received the James R. Holton Junior Scientist Award at the 2008 AGU Fall Meeting Honors Ceremony, held 17 December in San Francisco, Calif. The award recognizes outstanding research contributions by a junior atmospheric scientist within 3 years of his or her Ph.D.
Appropriateness Criteria for Bariatric Surgery: Beyond the NIH Guidelines
Authors: Yermilov Irina , McGory Marcia L. , Shekelle Paul W. , Ko Clifford Y. , Maggard Melinda A.
Published: April 2009

Careful selection of bariatric patients is critical for successful outcomes. In 1991, the NIH first established patient selection guidelines; however, some surgeons operate on individuals outside of these criteria, i.e., extreme age groups. We developed appropriateness criteria for the spectrum of patient characteristics including age, BMI, and severity of eight obesity‐related comorbidities. Candidate criteria were developed using combinations of patient characteristics including BMI: ≥40 kg/m2, 35–39, 32–34, 30–31, <30; age: 12–18, 19–55, 56–64, 65+ years old; and comorbidities: prediabetes, diabetes, hypertension, dyslipidemia, sleep apnea, venous stasis disease, chronic joint pain, and gastroesophageal reflux (plus severity level). Criteria were formally validated on their appropriateness of whether the benefits of surgery clearly outweighed the risks, by an expert panel using the RAND/UCLA modified Delphi method. Nearly all comorbidity severity criteria for patients with BMI ≥40 kg/m2 or BMI = 35–39 kg/m2 in intermediate age groups were found to be appropriate for surgery. In contrast, patients in the extreme age categories were considered appropriate surgical candidates under fewer conditions, primarily the more severe comorbidities, such as diabetes and hypertension. For patients with a BMI of 32–34, only the most severe category of diabetes (Hgb A1c >9, on maximal medical therapy), is an appropriate criterion for those aged 19–64, whereas many mild to moderate severity comorbidity categories are “inappropriate.” There is overwhelming agreement among the panelists that the current evidence does not support performing bariatric surgery in lower BMI individuals (BMI <32). This is the first development of appropriateness criteria for bariatric surgery that includes severity categories of comorbidities. Only for the most severe degrees of comorbidities were adolescent and elderly patients deemed appropriate for surgery. Patient selection for bariatric procedures should include consideration of both patient age and comorbidity severity.
DXA‐derived Abdominal Fat Mass, Waist Circumference, and Blood Lipids in Postmenopausal Women
Authors: Vatanparast Hassanali , Chilibeck Philip D. , Cornish Stephen M. , Little Jonathan P. , Paus‐Jenssen Lisa S. , Case Allison M. , Biem H. Jay
Published: April 2009

The purpose of this study was to determine the utility of dual‐energy X‐ray absorptiometry (DXA)‐derived fat mass indices for predicting blood lipid profile in postmenopausal women. A secondary purpose was to determine whether waist circumference is comparable with DXA‐derived measurements in predicting blood lipid profile. Subjects were 423 postmenopausal women (age 58.1 ± 6.3 years). Fat mass was assessed at abdomen, trunk, and total body using DXA. Anthropometric measurements included BMI and waist circumference. Blood samples were analyzed for total cholesterol (TC), triglyceride (TAG), high‐density lipoprotein (HDL), low‐density lipoprotein (LDL), and cholesterol/HDL ratio. Of the DXA‐derived measures, abdominal‐fat mass was the best predictor of blood lipid profiles. DXA‐derived abdominal fat mass and waist girth explained 20 and 16.5% of variation in TC/HDL ratio, respectively, in univariate analysis, with no difference between the slopes of the regression coefficients. Eighty‐four percent of subjects were common to the top quartiles of waist circumference and abdominal fat mass, and blood lipid profiles generally worsened across increasing quartiles. DXA‐derived abdominal fat mass and waist circumference are of equivalent utility for predicting alterations in blood lipids. Waist circumference is, therefore, ideal as an inexpensive means in primary health‐care services for predicting risk of cardiovascular diseases in postmenopausal women.
Spin glass behavior and magnetocaloric effect in amorphous alloys Ce2Fe23−xMnxB3
Authors: Wang Fang , Shen Jun , Zhang Jian , Sun Ji-rong , Shen Bao-gen
Published: April 2009

The magnetic properties and magnetocaloric effect of amorphous alloys Ce2Fe23−xMnxB3 (1≤x≤6) were investigated. The magnetic properties are sensitive to the composition. For samples with x≤3, the low fraction and isolated Fe–Mn antiferromagnetic (AFM) coupling simply align antiparallel to the majority ferromagnetic (FM) order and reduce the total magnetization but cause no noncollinearity; thus they are typical FM materials with TC decreasing drastically from 336 to 226 K and the magnetization has a sharp drop around respective TC without thermal hysteresis suggesting a second order phase transition resulting from their amorphous nature. For x=4 and 5, amorphous alloys Ce2Fe23−xMnxB3 experience two transitions: first a paramagnetic (PM)-FM second transition at 143 and 81 K, respectively, and then a FM–spin glass (SG) transition. A PM-SG transition occurs at the freezing temperature (Tf) about 28.2 K for x=6. The SG behavior in amorphous alloy Ce2Fe23−xMnxB3 can be attributed to the disordered structure resulting from their amorphous nature and the competition between the Fe–Fe FM coupling and Fe–Mn AFM negative coupling. The magnetic entropy change for alloys Ce2Fe23−xMnxB3 with x≤3 is calculated using the Maxwell relation.
Small angle x-ray and neutron scattering study of disordered and three dimensional–ordered magnetic protein arrays
Authors: Kasyutich O. , Tatchev D. , Hoell A. , Ogrin F. , Dewhurst C. , Schwarzacher W.
Published: April 2009

The magnetic nanoparticles of Fe3O4-γ–Fe2O3 grown inside the cavity of globular proteins (apoferritin)-magnetoferritin proved to be a useful model system for studying the fundamental effects of magnetostatic interactions in nanoparticle assemblies. In this work the main focus is on structural characterization of such new nanocomposites by small angle x-ray scattering (SAXS) and small angle neutron scattering to evaluate interparticle separation (center to center) in two types of assemblies: three dimensional periodic arrays and disordered (amorphous) assemblies. Straightforward analysis of the face-centered cubic pattern of periodic arrays revealed that the interparticle spacing is 9.9 nm, whereas the SAXS pattern of disordered assembly reveals three correlation lengths, one of which is 10.5 nm and corresponds to the interparticle (center-to-center) nearest neighbor distance. The magnetic behaviors of the two systems are distinctly different. Given that the interparticle separation differs by only ∼0.6 nm, the main structural factor contributing to the observed differences in magnetic properties is likely to be the array order.
Formation, trapping, and ejection of radiolytic O2 from ion-irradiated water ice studied by sputter depth profiling
Authors: Teolis B. D. , Shi J. , Baragiola R. A.
Published: April 2009

We report experimental studies of 100keV Ar+ ion irradiation of ice leading to the formation of molecular oxygen and its trapping and ejection from the surface, at temperatures between 80 and 150K. The use of a mass spectrometer and a quartz-crystal microbalance and sputter depth profiling at 20K with low energy Ar ions allowed us to obtain a consistent picture of the complex radiolytic mechanism. We show that the dependence of O2 sputtering on ion fluence is mainly due to the buildup of trapped O2 near the surface. A small proportion of the O2 is ejected above 130K immediately upon creation from a precursor such as OH or H2O2. The distribution of trapped oxygen peaks at or near the surface and is shallower than the ion range. Measurements of sputtering of H2 help to elucidate the role of this molecule in the process of O2 formation: out-diffusion leading to oxygen enrichment near the surface. The competing phenomena of OH diffusion away from the ion track and hydrogen escape from the ice and their temperature dependence are used to explain the finding of opposite temperature dependencies of O2 and H2O2 synthesis. Based on the new data and understanding, we discuss the application of our findings to ices in the outer solar system and interstellar space.
Nonstationary effects of the space charge in semiconductor structures
Authors: Garcia-Barrientos Abel , Grimalsky Volodymyr , Gutierrez-Dominguez Edmundo A. , Palankovski Vassil
Published: April 2009

A study of nonstationary effects of space charge in semiconductor structures, such as nonlinear wave interactions in active media operating in the microwave and millimeter wave range, is presented in this paper. Also, an exhaustive analysis of different models describing the propagation of space charge waves is carried out. Furthermore, we have concluded that the most appropriate nonlocal model to describe the space charge wave propagation in thin films possessing negative differential conductivity is the detailed balance model.
Small iron doped carbon clusters: A comparison with early and late first-row transition metal doped clusters
Authors: Largo Laura , Barrientos Carmen , Redondo Pilar
Published: April 2009

A systematic study of the three lowest-lying structures, namely, linear, fan, and cyclic, of neutral FeCn (n=1–8) clusters on the singlet, triplet, quintet, and septet potential energy surfaces has been carried out. Predictions for their electronic energies, rotational constants, dipole moments, and vibrational frequencies have been made using the B3LYP method in conjunction with the 6-311+G(d) basis set. Triplet or quintet states are found as the lowest-lying ones for FeCn clusters, and the septet states are found more stable than the singlet ones. The incremental binding energies show an even-odd parity effect, with n-even clusters being more stable than the n-odd ones in the linear and fan clusters, whereas a decrease with n is found for cyclic ones. The most stable isomers for FeCn clusters correspond to a fan-type structure for n⩽4, whereas for n⩾6 cyclic structures are the most stable. Only in the case of n=5 the most stable isomer is the linear structure. Comparing the results of FeCn clusters with the previously studied TMCn (TM=Sc, Ti, V, Co, and Zn) systems, we can see that, as it should be expected, iron doped carbon clusters present an intermediate behavior between early and late first-row transition metal doped clusters.
The effect of a magnetic field on a cylindrical object in a plasma
Authors: Zimmermann T. M. G. , Coppins M. , Allen J. E.
Published: April 2009

A two fluid model is applied to the presheath of a cylindrical object immersed in plasma under the influence of an axial magnetic field. The impact of the magnetic field on presheath behavior is studied and quantified by calculating the sheath edge potential and floating potential of the object. The latter is of great interest since it determines the cylinder’s charge. It is found that the density distribution in the presheath deviates significantly from the Boltzmann relation for electrons due to the presence of the magnetic field. This occurs because B opposes the radial flow of charge. However, the field not only inhibits transport of charge to the cylinder, but also deflects both fluids, setting up currents in the system, which increase the externally applied field. This effect can alter the field topology around the object significantly and makes it necessary to solve for the magnetic field self-consistently in some situations. The relevant parameter range is identified and a sample calculation with nonuniform B is shown. Interestingly, the magnetic field contribution due to the cylinder adds to the applied field, such that the object behaves as if it were ferromagnetic.
Current conduction mechanisms in Pr2O3/oxynitride laminated gate dielectrics
Authors: Chiu Fu-Chien , Lee Chun-Yen , Pan Tung-Ming
Published: April 2009

Metal-oxide-semiconductor capacitors with Pr2O3/oxynitride laminated gate dielectrics were fabricated. The current transportation of Al/Pr2O3/SiON/n-Si devices was studied at temperatures ranging from 300 to 400 K. The dominant conduction mechanism at low electric field (<0.6 MV/cm) is the hopping conduction in the laminated gate dielectrics. The determined hopping distance and activation energy is about 1.5 nm and 50±1 meV, respectively. However, the dominant conduction mechanism at high electric field (>2 MV/cm) is the Poole–Frenkel emission in which the trap energy level determined from Arrhenius plot is about 0.56±0.01 eV.
Characterizing nanometer-sized V-defects in InGaN single quantum well films by high-spatial-resolution cathodoluminescence spectroscopy
Authors: Yoshikawa M. , Murakami M. , Ishida H. , Harima H.
Published: April 2009

We studied cathodoluminescence (CL) spectral variations in the vicinity of the V-defects in InGaN single quantum well (SQW) films by using our newly developed SE-SEM-CL. The peak intensity and peak wavelength of the CL peaks around 448 and 400 nm were found to change significantly near the apex of a V-defect. These variations were mainly attributed to a change in the In content of the InGaN SQW layer in the sidewalls and apex of the V-defect. Furthermore, an abnormal change was observed in the CL peak at 365 nm near the apex of the V-defect; this change was mainly caused by the stress induced by a force at the film edge that results from the thermal expansion differences between the film and the GaN layer. On the basis of the obtained results, we proposed a model of the formation of V-defects by selective termination of the threading defects on the (0001) surface of pseudomorphic InGaN SQW and GaN buffer layers by In.
Electric field control of room temperature ferromagnetism in III-N dilute magnetic semiconductor films
Authors: Nepal N. , Luen M. Oliver , Zavada J. M. , Bedair S. M. , Frajtag P. , El-Masry N. A.
Published: April 2009

We report on the electrical field control of ferromagnetism (FM) at room temperature in III-N dilute magnetic semiconductor (DMS) films. A GaMnN layer was grown on top of an n-GaN substrate and found to be almost always paramagnetic. However, when grown on a p-type GaN layer, a strong saturation magnetization (Ms) was observed. This FM in GaMnN can be controlled by depletion of the holes in the GaMnN/p-GaN/n-GaN multilayer structures. We have demonstrated the dependence of the FM on the thickness of the p-GaN in this heterostructure and on the applied bias to the GaN p-n junction. The Ms was measured by an alternating gradient magnetometer (AGM) and a strong correlation between the hole concentration near the GaMnN/p-GaN interface and the magnetic properties of the DMS was observed. At room temperature an anomalous Hall effect was measured for zero bias and an ordinary Hall effect for reverse bias in a fully depleted p-GaN layer. This is in close agreement with the AGM measurement results.
Quenching of acoustic bandgaps by flow noise
Authors: Elnady T. , Elsabbagh A. , Akl W. , Mohamady O. , Garcia-Chocano V. M. , Torrent D. , Cervera F. , Sánchez-Dehesa J.
Published: April 2009

We report an experimental study of acoustic effects produced by wind impinging on noise barriers based on two-dimensional sonic crystals with square symmetry. We found that the attenuation strength of sonic-crystal bandgaps decreases for increasing values of flow speed. A quenching of the acoustic bandgap appears at a certain speed value that depends of the barrier filling ratio. For increasing values of flow speed, the data indicate that the barrier becomes a sound source because of its interaction with the wind. We conclude that flow noise should be taken into account in designing acoustic barriers based on sonic crystals.
Circularly polarized lasing in a (110)-oriented quantum well vertical-cavity surface-emitting laser under optical spin injection
Authors: Fujino Hiroshi , Koh Shinji , Iba Satoshi , Fujimoto Toshiyasu , Kawaguchi Hitoshi
Published: April 2009

We fabricated and characterized a vertical-cavity surface-emitting laser (VCSEL) based on (110) InGaAs/GaAs multiple quantum wells (MQWs). Circularly polarized lasing in the (110) VCSEL by optical injection of spin-polarized electrons has been demonstrated at 77 K and room temperature. A high degree of circular polarization, 0.94, was observed at 77 K, reflecting the long electron spin relaxation time in the (110) MQWs.
First-principles calculation of nitrogen-tungsten codoping effects on the band structure of anatase-titania
Authors: Long Run , English Niall J.
Published: April 2009

The electronic properties and photocatalytic activity of nitrogen (N) and/or tungsten (W)-doped anatase are calculated using density functional theory. For N-doping, isolated N 2p states above the top of the valence band are responsible for experimentally observed redshifts in the optical absorption edge. For W-doping, W 5d states below the conduction band lead to band gap narrowing; the transition energy is reduced by 0.2 eV. Addition of W to the N-doped system yields significant band gap narrowing gap by 0.5 eV. This rationalizes recent experimental data which showed that N/W-doped titania exhibits higher visible-light photocatalytic efficiency than either N- or W-doping alone.
The effect of the internal capacitance of InGaN-light emitting diode on the electrostatic discharge properties
Authors: Jeon Soo-Kun , Lee Jae-Gab , Park Eun-Hyun , Jang Jin , Lim Jae-Gu , Kim Seo-Kun , Park Joong-Seo
Published: April 2009

The electrostatic discharge (ESD) properties of the InGaN-light emitting diode (LED) were investigated in terms of the internal capacitance of the InGaN-LED. The LEDs with higher internal capacitance were found to be more resistant to external ESD impulses. The internal capacitance of the InGaN-LED was controlled by the silicon doping level of the n-GaN layer bordering the active layer. The human body model ESD yield at −500 V was increased from 27% to 94% by increasing the internal capacitance. Moreover, the high ESD pass yield was maintained up to −7000 V.
Reconstructing Fossil Sub-structures of the Galactic Disk: Clues from Abundance Patterns of Old Open Clusters and Moving Groups
Authors: De Silva G. M. , Freeman K. C. , Bland-Hawthorn J.
Published: April 2009

The long term goal of large-scale chemical tagging is to use stellar elemental abundances as a tracer of dispersed substructures of the Galactic disk. The identification of such lost stellar aggregates and the exploration of their chemical properties will be key in understanding the formation and evolution of the disk. Present day stellar structures such as open clusters and moving groups are the ideal testing grounds for the viability of chemical tagging, as they are believed to be the remnants of the original larger star-forming aggregates. Until recently, high accuracy elemental abundance studies of open clusters and moving groups having been lacking in the literature. In this paper we examine recent high resolution abundance studies of open clusters to explore the various abundance trends and reasses the prospects of large-scale chemical tagging.
Potential role of phenotypic mutations in the evolution of protein expression and stability
Authors: Goldsmith Moshe , Tawfik Dan S.
Published: April 2009

Phenotypic mutations (errors occurring during protein synthesis) are orders of magnitude more frequent than genetic mutations. Consequently, the sequences of individual protein molecules transcribed and translated from the same gene can differ. To test the effects of such mutations, we established a bacterial system in which an antibiotic resistance gene (TEM-1 β-lactamase) was transcribed by either a high-fidelity RNA polymerase or its error-prone mutant. This setup enabled the analysis of individual mRNA transcripts that were synthesized under normal or error-prone conditions. We found that an increase of ≈20-fold in the frequency of transcription errors promoted the evolution of higher TEM-1 expression levels and of more stable enzyme variants. The stabilized variants exhibited a distinct advantage under error-prone transcription, although under normal transcription they conferred resistance similar to wild-type TEM-1. They did so, primarily, by increasing TEM-1's tolerance to destabilizing deleterious mutations that arise from transcriptional errors. The stabilized TEM-1 variants also showed increased tolerance to genetic mutations. Thus, although phenotypic mutations are not individually subjected to inheritance and natural selection, as are genetic mutations, they collectively exert a direct and immediate effect on protein fitness. They may therefore play a role in shaping protein traits such as expression levels, stability, and tolerance to genetic mutations.
Persian Linguistics in the Twentieth Century
Authors: Taleghani Azita H.
Published: April 2009

This article focuses on Persian linguistics with the emphasis on grammar and word formation in the twentieth century. After presenting a brief overview of the history of the study of grammar in Iran, I discuss the recent trends in linguistics from diachronic to synchronic aspects. In Persian diachronic linguistics, we will see that most works focus on the reading, and deciphering of the old texts. In synchronic studies, there are three main stages: 1) traditional linguistics, 2) structural linguistics, and 3) generative or formal linguistics. I show how each one of these stages affects Persian linguistics in the twentieth century. Finally, I conclude the article by looking at the current state of Persian linguistics and the future prospects for the field.
Theoretical Extremes of the Study of Mystic Man in Modern Iran: Review Article
Authors: Lewisohn Leonard
Published: April 2009

Highlighting certain fallacies in a recent anthropological study of three branches of the Ni‘matu’llāhī Sufi Order in modern Iran, this review article tries to cast light on the little-understood relationship between legalistic Islam and Persian Sufism. It also attempts to clarify the connection (or rather, lack thereof) between Sufism and the Pahlavi state and the current Islamist regime, while discussing the subtle distinction betweenand‘irfānin the mystical philosophies of Shi‘ite Islam. Some of the vicissitudes of three decades (1978–2008) of suppression and persecution of Sufis by the fundamentalist Shi‘ite state in Iran are also chronicled.
On the asymptotics of Whittaker functions
Authors: Lapid Erez , Mao Zhengyu
Published: April 2009

We study the asymptotics of Whittaker functions on split groups and relate them to the cuspidal exponents of the representation.
Mitochondrial whims: metabolic rate, longevity and the rate of molecular evolution
Authors: Galtier Nicolas , Jobson Richard W. , Nabholz Benoît , Glémin Sylvain , Blier Pierre U.
Published: April 2009

The evolutionary rate of mitochondrial DNA (mtDNA) is highly variable across lineages in animals, and particularly in mammals. This variation has been interpreted as reflecting variations in metabolic rate: mitochondrial respiratory activity would tend to generate mutagenic agents, thus increasing the mutation rate. Here we review recent evidence suggesting that a direct, mechanical effect of species metabolic rate on mtDNA evolutionary rate is unlikely. We suggest that natural selection could act to reduce the (somatic) mtDNA mutation rate in long-lived species, in agreement with the mitochondrial theory of ageing.
Reduced heterozygosity impairs sperm quality in endangered mammals
Authors: Fitzpatrick John L. , Evans Jonathan P.
Published: April 2009

Inbreeding causes increases in homozygosity and is commonly associated with reductions in fertility and embryogenesis. Although the mechanisms underlying such effects are unknown, recent work has suggested that inbred males may suffer impaired ejaculate quality, thus providing a functional explanation for reductions in reproductive function in inbred populations. However, the relationship between inbreeding and sperm quality remains controversial, particularly in wild populations where the level of inbreeding is typically estimated using neutral molecular markers. Such markers are thought to reflect genome-wide levels of heterozygosity only under restricted conditions, and rarely in outbred populations. Here we employ a comparative approach that takes account of these criticisms and evaluates the evidence linking inbreeding to reductions in sperm quality in 20 mammal species. We focus on sperm abnormalities and sperm motility, which are key determinants of male fertility in many species. We show that species with reduced mean heterozygosity have impaired ejaculated quality, although subsequent analyses revealed that these effects were confined to endangered populations. Our findings therefore support the notion that inbreeding can severely impair sperm quality while concomitantly addressing criticisms surrounding the use of heterozygosity estimates to estimate the level of inbreeding.
Behavioural phase polyphenism in the Australian plague locust (
Chortoicetes terminifera
)
Authors: Gray Lindsey J. , Sword Gregory A. , Anstey Michael L. , Clissold Fiona J. , Simpson Stephen J.
Published: April 2009

Swarming and the expression of phase polyphenism are defining characteristics of locust species. Increases in local population density mediate morphological, physiological and behavioural changes within individuals, which correlate with mass marching of juveniles in migratory bands and flying swarms of adults. The Australian plague locust (
Chortoicetes terminifera
) regularly forms migratory bands and swarms, but is claimed not to express phase polyphenism and has accordingly been used to argue against a central role for phase change in locust swarming. We demonstrate that juvenile
C. terminifera
express extreme density-dependent behavioural phase polyphenism. Isolated-reared juveniles are sedentary and repelled by conspecifics, whereas crowd-reared individuals are highly active and are attracted to conspecifics. In contrast to other major locust species, however, behavioural phase change does not accumulate across generations, but shifts completely within an individual's lifetime in response to a change in population density.
Trade-off between age of first reproduction and survival in a female primate
Authors: Blomquist Gregory E.
Published: April 2009

Trade-offs are central to life-history theory but difficult to document. Patterns of phenotypic and genetic correlations in rhesus macaques,Macaca mulatta—a long-lived, slow-reproducing primate—are used to test for a trade-off between female age of first reproduction and adult survival. A strong positive genetic correlation indicates that female macaques suffer reduced adult survival when they mature relatively early and implies primate senescence can be explained, in part, by antagonistic pleiotropy. Contrasts with a similar human study implicate the extension of parental effects to later ages as a potential mechanism for circumventing female life-history trade-offs in human evolution.
Sex allocation and sexual conflict in simultaneously hermaphroditic animals
Authors: Schärer Lukas , Janicke Tim
Published: April 2009

Links between sex allocation (SA) and sexual conflict in simultaneous hermaphrodites have been evident since Charnov's landmark paper published 30 years ago. We discuss two links, namely the potential for sexual conflict over SA between sperm donor and recipient, and the importance of post-copulatory sexual selection and the resulting sexual conflict for the evolution of SA. We cover the little empirical and theoretical work exploring these links, and present an experimental test of one theoretical prediction. The link between SA and sexual conflict is an interesting field for future empirical and theoretical research.
Bioinspired interface for nanobiodevices based on phospholipid polymer chemistry
Authors: Ishihara Kazuhiko , Takai Madoka
Published: April 2009

This review paper describes novel biointerfaces for nanobiodevices. Biocompatible and non-biofouling surfaces are designed largely based on cell membrane structure, and the preparation and functioning of the bioinspired interface are evaluated and compared between living and artificial systems. A molecular assembly of polymers with a phospholipid polar group has been developed as the platform of the interface. At the surface, protein adsorption is effectively reduced and the subsequent bioreactions are suppressed. Through this platform, biomolecules with a high affinity to the specific molecules are introduced under mild conditions. The activity of the biomolecules is retained even after immobilization. This bioinspired interface is adapted to construct bionanodevices, that is, microfluidic chips and nanoparticles for capturing target molecules and cells. The interface functions well and has a very high efficiency for biorecognition. This bioinspired interface is a promising universal platform that integrates various fields of science and has useful applications.
Biomaterial technology for tissue engineering applications
Authors: Tabata Yasuhiko
Published: April 2009

Tissue engineering is a newly emerging biomedical technology and methodology to assist and accelerate the regeneration and repairing of defective and damaged tissues based on the natural healing potentials of patients themselves. For the new therapeutic strategy, it is indispensable to provide cells with a local environment that enhances and regulates their proliferation and differentiation for cell-based tissue regeneration. Biomaterial technology plays an important role in the creation of this cell environment. For example, the biomaterial scaffolds and the drug delivery system (DDS) of biosignalling molecules have been investigated to enhance the proliferation and differentiation of cell potential for tissue regeneration. In addition, the scaffold and DDS technologies contribute to develop the basic research of stem cell biology and medicine as well as obtain a large number of cells with a high quality for cell transplantation therapy. A technology to genetically engineer cells for their functional manipulation is also useful for cell research and therapy. Several examples of tissue engineering applications with the cell scaffold and DDS of growth factors and genes are introduced to emphasize the significance of biomaterial technology in new therapeutic and research fields.
Designing and encoding models for synthetic biology
Authors: Endler Lukas , Rodriguez Nicolas , Juty Nick , Chelliah Vijayalakshmi , Laibe Camille , Li Chen , Le Novère Nicolas
Published: April 2009

A key component of any synthetic biology effort is the use of quantitative models. These models and their corresponding simulations allow optimization of a system design, as well as guiding their subsequent analysis. Once a domain mostly reserved for experts, dynamical modelling of gene regulatory and reaction networks has been an area of growth over the last decade. There has been a concomitant increase in the number of software tools and standards, thereby facilitating model exchange and reuse. We give here an overview of the model creation and analysis processes as well as some software tools in common use. Using markup language to encode the model and associated annotation, we describe the mining of components, their integration in relational models, formularization and parametrization. Evaluation of simulation results and validation of the model close the systems biology ‘loop’.