bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of deviation from the mid‐sagittal plane on the measurement of fetal nuchal translucency
Authors: Abele H. , Wagner N. , Hoopmann M. , Grischke E.‐M. , Wallwiener D. , Kagan K. O.
Published: February 2010

Objective

Screening for trisomy 21 by fetal nuchal translucency (NT) thickness at 11 to 13 + 6 weeks' gestation requires an appropriate examination of the NT. Errors in the assessment of NT may lead to an under‐ or overestimation of the NT and to incorrect patient‐specific risks. In this study we aimed to examine the importance of the mid‐sagittal section and whether the acquired plane of the head and face influences the measurement of the fetal NT thickness.

Methods

Sixty three‐dimensional volumes of the fetal head and face in a mid‐sagittal plane were acquired. NT thickness was firstly measured in the mid‐sagittal plane according to the guidelines of The Fetal Medicine Foundation. The head was then rotated by steps of 5° up to 25° around the mid‐point of the biparietal diameter and occipitofrontal diameter and NT was measured again. All six NT measurements were taken by the same operator, Operator A, who on completion of the assessment of the 60 volumes repeated all the measurements. The whole process was then repeated by Operator B. Both operators were blinded to each others' measurements.

Results

In the true mid‐sagittal plane, the mean NT was 1.9 mm and it was above the expected median in 72.5% of the measurements. At a deviation of 15°, mean NT was 1.5 mm, and 36.3% of the measurements were above the expected median. At a deviation of 25°, mean NT was reduced to 1.3 mm and 17.9% of the measurements were above the expected median.

Conclusion

Fetal NT thickness is greatest in the mid‐sagittal plane. Increasing deviation away from the mid‐sagittal plane results in progressive underestimation of the fetal NT thickness and so to a corresponding underestimation of the patient‐specific risk. Copyright © 2010 ISUOG. Published by John Wiley & Sons, Ltd.
Fetal biometry by an inexperienced operator using two‐ and three‐dimensional ultrasound
Authors: Yang F. , Leung K. Y. , Lee Y. P. , Chan H. Y. , Tang M. H. Y.
Published: February 2010

Objective

To compare the reproducibility, accuracy and time required for fetal biometric measurements using two‐dimensional (2D) and three‐dimensional (3D) ultrasonography by an inexperienced operator.

Methods

Fifty consecutive fetuses were evaluated at a gestational age of 17–34 weeks. For every fetus measurements—including biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC) and femur length (FL)—were made by an inexperienced operator using 2D ultrasound and then saved 3D volumes. As a control, measurements were also made by an experienced operator using 2D ultrasonography alone. Each fetal biometric parameter was measured twice by each operator. All images were assessed by two experienced reviewers, blinded to the operator's identity, using a scoring system based on objective evaluation criteria.

Results

The interobserver, intraobserver and inter‐ method variability for 2D ultrasonography by the experienced operator (2D‐exp), and 2D and 3D ultrasonography by the inexperienced operator (2D‐inexp and 3D‐inexp) was small (all intraclass correlation coefficients ≥ 0.991). A non‐significantly higher proportion of fetal biometric measurements by 3D‐inexp than 2D‐inexp were within 1 mm of the measurements by 2D‐exp. There were no differences in the mean image quality scores of fetal biometry between 2D‐exp and 2D‐inexp, 2D‐exp and 3D‐inexp. However, the quality score of AC images obtained by 3D‐inexp was greater than that obtained by 2D‐inexp (5.5 vs. 5.3, P = 0.018). The mean time required to measure BPD, HC, AC and FL was less for 3D‐inexp than for 2D‐inexp (67.2 vs. 97.0 s, 64.6 vs. 97.0 s, 60.1 vs. 81.5 s and 65.5 vs. 95.1 s, respectively; all P < 0.001), but was significantly greater than for 2D‐exp, with corresponding figures of 24.3, 24.3, 27.9 and 27.2 s.

Conclusion

Fetal biometric measurements obtained by an inexperienced operator using both 2D and 3D ultrasound were reproducible and showed good agreement with those obtained by an experienced operator. The use of 3D ultrasound by an inexperienced operator allows faster measurements to be made than by 2D ultrasound and also seems to facilitate the acquisition of higher‐quality images for measurement of AC. Copyright © 2010 ISUOG. Published by John Wiley & Sons, Ltd.
Decision/action, philosophical issues about
Authors: Mele Alfred R.
Published: February 2010

Are conscious decisions or intentions ever among the causes of corresponding intentional actions? This article provides conceptual background for an examination of this question, including a discussion of the nature of decisions, intentions, and actions and a sketch of a model of conscious deciding. It also examines evidence that conscious decisions and intentions sometimes play a role in producing corresponding actions. Copyright © 2010 John Wiley & Sons, Ltd.

This article is categorized under:

Philosophy > Action
Infant memory
Authors: Bauer Patricia J. , San Souci Priscilla , Pathman Thanujeni
Published: February 2010

This article provides an overview of developments in long‐term memory during the first 2 years of life. Results from three of the most commonly used techniques to assess remembering in preverbal infants—visual paired comparison and visual habituation, conjugate reinforcement, and elicited and deferred imitation—are described. They illustrate infants' ability to encode and retain information as well as the rapid improvements in memory in infancy. A distinction between types or forms of memory is provided in the service of considering how infant memory abilities relate to memory development in early childhood. The review also features discussion of the likely sources of age‐related changes in memory in infancy, including the basic processes of memory trace formation and developments in the neural substrate that subserve them. Copyright © 2010 John Wiley & Sons, Ltd.

This article is categorized under:

Psychology > Memory

Neuroscience > Development
Meta‐analysis of neuroimaging data
Authors: Kober Hedy , Wager Tor D.
Published: February 2010

As the number of neuroimaging studies that investigate psychological phenomena grows, it becomes increasingly difficult to integrate the knowledge that has accrued across studies. Meta‐analyses are designed to serve this purpose, as they allow the synthesis of findings not only across studies but also across laboratories and task variants. Meta‐analyses are uniquely suited to answer questions about whether brain regions or networks are consistently associated with particular psychological domains, including broad categories such as working memory or more specific categories such as conditioned fear. Meta‐analysis can also address questions of specificity, which pertains to whether activation of regions or networks is unique to a particular psychological domain, or is a feature of multiple types of tasks. This review discusses several techniques that have been used to test consistency and specificity in published neuroimaging data, including the kernel density analysis (KDA), activation likelihood estimate (ALE), and the recently developed multilevel kernel density analysis (MKDA). We discuss these techniques in light of current and future directions in the field. Copyright © 2010 John Wiley & Sons, Ltd.

This article is categorized under:

Neuroscience > Cognition
[3+2] Cycloadditions of Metallo Nitrile Ylides and Metallo Nitrile Imines with Metal Carbonyl, Thiocarbonyl, and Isocyanide Complexes: Heterodimetallic Systems with Bridging Heterocycles [1]
Authors: Schoder Friedrich , Plaia Ulrike , Metzner Robert , Sperber Wilfried , Beck Wolfgang , Fehlhammer Wolf Peter
Published: February 2010

The reactions of [Re(CO)6]+, [FeCp(CO)2CS]+ and [FeCp(CNPh)3]+ with the metallo nitrile ylides [M–{C+=N–C–(H)CO2Et}(CO)5]– (M = Cr, W) and the chromio nitrile imine [Cr–{C+=N–N–H}(CO)5]– (generated by mono‐α‐deprotonation of the parent isocyanide complexes) to give neutral 5‐metallated 1,3‐oxazolin‐ (1), 1,3‐thiazolin‐ (2), imidazolin‐ (3, 4), 1,3,4‐oxdiazolin‐ (5), 1,3,4‐thiadiazolin‐ (6) and 1,3,4‐triazolin‐2‐ylidene (8) chromium and tungsten complexes represent the first all‐organometallic versions of Huisgen’s 1,3‐dipolar cycloadditions. The formation of 6 and 8 is accompanied by partial decomposition to (OC)5Cr–C≡N–FeCpL2 {L = CO (7), CNPh (9)}. The structures of 4a and 5 have been characterized by X‐ray diffraction.
Reaktionen der Digalliumverbindung R2Ga–GaR2 [R = CH(SiMe3)2] mit Wasser und Carbonsäuren – Synthese von μ‐Hydroxo‐μ‐carboxylatodigallium‐Verbindungen unter Erhalt der Ga–Ga‐Bindungen
Authors: Uhl Werner , Bock Henrik R. , Hepp Alexander , Rogel Friedhelm , Voß Matthias
Published: February 2010

Treatment of the digallium compound R2Ga–GaR2 [1, R = CH(SiMe3)2] with a broad variety of functionalized carboxylic acids in the presence of water yielded μ‐hydroxo‐μ‐carboxylatodigallium compounds (2–10) containing intact Ga–Ga bonds in high to moderate yields. The compounds form dimeric formula units in which the unsupported Ga–Ga bonds are bridged by two hydroxo and two carboxylato ligands. Each gallium atom is terminally coordinated by a bulky alkyl group. NMR spectroscopy revealed mixtures of two isomeric compounds in solution in all cases. The second component may show a different bridging mode with each Ga–Ga bond bridged by a bidentate carboxylato ligand to form Ga2O2C five‐membered heterocycles.
Current State of Gastric Stump Carcinoma in Japan: Based on the Results of a Nationwide Survey
Authors: Tanigawa Nobuhiko , Nomura Eiji , Lee Sang‐Woong , Kaminishi Michio , Sugiyama Mitsugu , Aikou Takashi , Kitajima Masaki ,   The Society for the Study of Postoperative Morbidity after Gastrectomy
Published: February 2010

Background

Carcinoma of the gastric remnant after partial gastrectomy for benign disease or cancer is unusual but an important cancer model. The Japanese Society for the Study of Postoperative Morbidity after Gastrectomy (JSSPMG) performed a nationwide questionnaire survey to understand the current state of gastric stump carcinoma in Japan.

Methods

In the questionnaire survey of November 2008, gastric stump carcinoma was defined as an adenocarcinoma of the stomach occurring 10 years or more after Billroth I or Billroth II gastrectomy for benign condition or cancer disease. The survey was conducted at the request of reports on five or more patients with gastric stump carcinoma for each institution. Items for the survey included gender, age, methods of reconstruction in an original gastrectomy, original diseases, time interval between original gastrectomy and first detection of stump carcinomas, locations of stump carcinomas, tumor histology, tumor depth, and extent of lymph node metastasis. The questionnaire was sent to 163 surgical institutions in the JSSPMG.

Results

Ninety‐five institutions (58.3%) responded to the survey, and the data of 887 patients satisfied the required conditions for the survey. A total of 887 patients were composed of 368 patients who received Billroth I distal gastrectomy and 519 who received Billroth II. The Billroth II group has a significantly higher number of original benign lesions than the Billroth I group (P < 0.001). This study confirmed the following issues: (1) The remnant stomach after gastrectomy for cancer disease had a higher prevalence to develop stump carcinomas occurring in a shorter time interval since original gastrectomy; (2) Patients with Billroth II gastrectomy had stump carcinomas most frequently in the anastomotic area, but not in the non‐stump area as in Billroth I gastrectomy; (3) Tumor histology of 72.4% of 304 stump carcinomas at an early stage was intestinal type adenocarcinoma, i.e., well or moderately differentiated adenocarcinoma, whereas it decreased to 42.2% at the locally advanced stage of 521 stump carcinomas (P = 0.0015), suggesting that stump carcinoma mostly may develop from intestinal type and change to diffuse type during the evolution to advanced stage cancers.

Conclusions

This large series of surveys suggest that there are two distinct biological plausibilities in the development of gastric stump carcinoma: (1) it develops in a shorter time interval of 10 years or less since the original gastrectomy, may come from a higher risk of gastric mucosa after gastrectomy for cancer diseases that highly predisposes to cancer, and (2) it develops during a longer time interval of 20 years or more, may come from gastrectomy‐relating mechanisms after gastrectomy for original benign diseases.
R&D challenges and solutions for mobile cyber-physical applications and supporting Internet services
Authors: White Jules , Clarke Siobhan , Groba Christin , Dougherty Brian , Thompson Chris , Schmidt Douglas C.
Published: February 2010

The powerful processors and variety of sensors in new and planned mobile Internet devices, such as Apple’s iPhone and Android-based smartphones, can be leveraged to build cyber-physical applications that collect sensor data from the real world and communicate it back to Internet services for processing and aggregation. This article presents key R&D challenges facing developers of mobile cyber-physical applications that integrate with Internet services and summarizes emerging solutions to address these challenges. For example, application software should be architected to conserve power, which motivates R&D on tools that can predict the power consumption characteristics of mobile software architectures. Other R&D challenges involve the relative paucity of work on software and sensor data collection architectures that cater to the powerful capabilities and cyber-physical aspects of mobile Internet devices, which motivates R&D on architectures tailored to the latest mobile Internet devices.
Beneficial effects of dietary restriction in type 2 diabetic rats: the role of adipokines on inflammation and insulin resistance
Authors: Crisóstomo Joana , Rodrigues Lisa , Matafome Paulo , Amaral Carmen , Nunes Elsa , Louro Teresa , Monteiro Pedro , Seiça Raquel
Published: February 2010

Inflammation plays an important role in diabetes mellitus and its complications. In this context, the negative cross-talk between adipose tissue and skeletal muscle leads to disturbances in muscle cell insulin signalling and induces insulin resistance. Because several studies have shown that energy restriction brings some benefits to diabetes, the aim of the present study was to evaluate the effects of dietary restriction on systemic and skeletal muscle inflammatory biomarkers, such C-reactive protein, adipokines and cytokines, and in insulin resistance in Goto-Kakizaki rats. This is an animal model of spontaneous non-obese type 2 diabetes with strongly insulin resistance and without dyslipidaemia. Animals were maintained during 2 months of dietary restriction (50 %) and were killed at 6 months of age. Some biochemical determinations were done using ELISA and Western blot. Data from the present study demonstrate that in Goto-Kakizaki rats the dietary restriction improved insulin resistance, NEFA levels and adipokine profile and ameliorated inflammatory cytokines in skeletal muscle. These results indicate that dietary restriction in type 2 diabetes enhances adipose tissue metabolism leading to an improved skeletal muscle insulin sensitivity.
Fruit and vegetable intake and risk of acute coronary syndrome
Authors: Hansen Louise , Dragsted Lars O. , Olsen Anja , Christensen Jane , Tjønneland Anne , Schmidt Erik B. , Overvad Kim
Published: February 2010

Prospective epidemiological studies have reported that a higher fruit and vegetable intake is associated with a lower risk of CHD. The aim of the present study was to examine associations between fruit and vegetable consumption, in particular the subgroupings citrus fruits, apples and cruciferous vegetables, and the risk of acute coronary syndrome (ACS). During a median follow-up of 7·7 years, 1075 incident ACS cases were identified among 53 383 men and women, aged 50–64 years at recruitment into the Diet, Cancer and Health cohort study in 1993–7. Fruit and vegetable intake was estimated from a validated FFQ, and ACS incidence rate ratios (IRR) were estimated using Cox proportional hazards models. Overall, a tendency towards a lower risk of ACS was observed for both men and women with higher fruit and vegetable consumption. For men, we found an inverse association for apple intake (IRR per 25 g/d: 0·97; 95 % CI 0·94, 0·99). This association was also seen among women, albeit borderline significant. However, a higher risk was seen among women with higher fruit juice intake (IRR per 25 g/d: 1·04; 95 % CI 1·00, 1·08). The present results provide some support for previously observed inverse associations between fresh fruit intake, particularly apples, and ACS risk.
The diel oviposition periodicity of Aedes aegypti (L.) (Diptera: Culicidae) in Trinidad, West Indies: effects of forced egg retention
Authors: Chadee D.D.
Published: February 2010

The diel oviposition periodicity of two groups of Aedes aegypti females (Trinidad strain), (i) thoses allowed access to oviposition sites and (ii) females forced to retain-eggs for four days, were studied under laboratory conditions using one female per cage and monitoring by changing substrates every two hours. The individual females which were allowed access to oviposition sites showed peak oviposition between 16.00–18.00 h (50% of eggs), whereas individuals forced to retain eggs for four days showed a similar pattern but with a significantly (P<0.001) larger peak oviposition between 16.00–18.00 h (94% of eggs). However, females forced to retain eggs laid most or all of their eggs in one container (84%), while females given access to oviposition sites distributed their eggs among 2–4 containers. The results of this study are discussed in the context of the strength of the circadian rhythms, oviposition strategies and its impact on vector control activities.
DISCRIMINATION-RELATED STRESS, BLOOD PRESSURE AND EPSTEIN-BARR VIRUS ANTIBODIES AMONG LATIN AMERICAN IMMIGRANTS IN OREGON, US
Authors: McCLURE HEATHER H. , MARTINEZ CHARLES R. , SNODGRASS J. JOSH , EDDY J. MARK , JIMÉNEZ ROBERTO A. , ISIORDIA LAURA E. , McDADE THOMAS W.
Published: February 2010

Perceived discrimination has been linked to poor health outcomes among ethnic and racial minorities in the United States, though the relationship of discrimination-related stress to immigrant health is not well understood. This article reports findings from a preliminary study that examined blood pressure and Epstein-Barr virus antibody levels in relation to self-reported indicators of stress, acculturation and social support among 79 adult immigrant Latino farm workers in Oregon, US. Findings show that increases in discrimination-related stress predicted elevated systolic blood pressure (SBP) and Epstein-Barr virus antibody levels among male participants. Though female participants reported similar levels of discrimination stress, this perceived stress was not reflected in biological measures. Among women, greater English language engagement was linked to higher SBP, and more years in the US was associated with higher diastolic blood pressure. Study results suggest that male and female immigrants' physiological responses to stress may be influenced in distinctive ways by processes of adjustment to life in the US. If replicated, the finding that discrimination stress predicts elevated SBP may have clinical and public health implications given that elevated SBP is an established risk factor for cardiovascular disease.
Clinical and functional characterisation of rheumatic mitral regurgitation in children and adolescents including the brain natriuretic peptide
Authors: Ribeiro Maria C. V. , Markman Filho Brivaldo , Santos Cleusa C. L. , Mello Cristina P. Q.
Published: February 2010

Rheumatic fever is a public health problem of universal distribution, predominantly affecting individuals in developing countries. In individuals less than 20 years of age, pure mitral regurgitation is the most commonly found condition in chronic rheumatic valve disease. In the present study, rheumatic mitral regurgitation was assessed in children and adolescents, addressing its clinical (duration of the disease, symptoms, use of benzathine penicillin, and number of outbreaks of the acute phase of rheumatic fever), electrocardiographic (left atrium abnormality and/or left ventricle hypertrophy) and echocardiographic characteristics (left atrium and ventricle measurements, ejection fraction and pulmonary artery pressure), as well as plasma dose of N-terminal portion of the brain natriuretic peptide through electrochemiluminescence immunoassay. Fifty-three patients were studied. The patients had moderate (41.5%) or severe (58.5%) rheumatic mitral regurgitation; had not undergone surgery; were not in the acute phase of the disease; and were being treated at a paediatric cardiology reference hospital in Northeastern Brazil. Mean patient age was 10.6 years (minimum of 3 and maximum of 19 years). With the exception of the ejection fraction, the echocardiographic variables had a significant correlation to the natriuretic peptide, demonstrating that this hormone reflects the haemodynamic consequences of mitral regurgitation. It was concluded that cardiac remodelling that occurs in rheumatic mitral regurgitation in children and adolescents leads to the production of the brain natriuretic peptide, which could be used as a complementary diagnostic tool in the follow-up of such patients.
Ebstein’s malformation presenting with tricuspid stenosis: 1-year follow-up after surgical repair
Authors: Khouzam Rami N. , Dearani Joseph A. , Julsrud Paul R.
Published: February 2010

This is a case of a young woman previously completely healthy, with two uneventful pregnancies and deliveries, who presented with bloating, shortness of breath, and signs of right heart failure. A thorough clinical evaluation, along with a work-up including an echocardiogram and a magnetic resonance imaging revealed the diagnosis of Ebstein’s anomaly malformation with tricuspid stenosis. A right ventricular outflow tract obstruction due to thrombus formation was thought to exacerbate her symptoms and lead to the diagnosis. Surgery in the form of right ventricular thrombectomy, right atrial reduction, porcine tricuspid valve replacement and bidirectional cavopulmonary anastomosis “bidirectional Glenn”, was successfully performed. The patient has been stable clinically more than one year after surgery. Discussion about this rare condition and operative details are provided.
An evaluation of the impact of a large group psycho-education programme (Stress Control) on patient outcome: does empathy make a difference?
Authors: Joice Anne , Mercer Stewart W.
Published: February 2010

Large psycho-education groups are being increasingly used in mental-health promotion and the treatment of common mental-health problems. In individual therapy there is a well-established link between therapist empathy, therapeutic relationship and patient outcome but the role of empathy within large psycho-educational groups is unknown. This service evaluation investigated the impact of a 6-week large psycho-education group on patient outcome and the role of perceived therapist empathy on outcome. Within a before–after experimental design, 66 participants completed baseline and endpoint measures; Clinical Outcome Routine Evaluation (CORE), Patient Enablement Instrument (PEI), and the modified Consultation and Relational Empathy (CARE) measure. The results showed that the intervention had a positive impact on patient outcome; the CORE score reduced significantly over the 6 weeks by 0.63 (95% CI 0.82–1.14) (t= 9.18, d.f. = 55,p= <0.001) and attendees felt highly enabled. Attendees perceived the course leader as highly empathetic. However, the relationship between perceived empathy and attendee outcome was less clear; no significant relationship was found with the main outcome measure (the change in CORE score). Factors that influenced the main outcome included age, symptom severity at baseline, having a long-term illness or disability, and whether attendees tried the techniques at home (homework). These findings suggest that large group psycho-education is an effective treatment for mild to moderate mental-health problems, at least in the short term. The role of therapist empathy remains ambiguous but may be important for some patient outcomes.
What drives short‐ and long‐term crustal deformation in the southwestern United States?
Authors: Yang Youqing , Liu Mian
Published: February 2010

The driving forces for crustal deformation are often inferred from the crustal kinematics. In the Southwestern United States, however, crustal kinematics delineated by the Global Positioning System (GPS) measurements differs significantly from that reconstructed from the geological records. This discrepancy is likely due to the different timescales reflected in these datasets. Here we explore the geodynamic links between the short‐ and long‐term crustal deformation in the Southwestern US using regional‐scale three‐dimensional elastic and viscous finite element models. We show that the GPS‐measured short‐term crustal deformation results mainly from interseismic traction along the San Andreas Fault (SAF). Much of the short‐term strain is transient that does not contribute to permanent deformation. The long‐term traction on the SAF is ∼10 MPa lower than that constrained by the GPS data, which, together with gravitational spreading, can reproduce the geologically reconstructed long‐term crustal deformation.
Can we estimate local Love wave dispersion properties from collocated amplitude measurements of translations and rotations?
Authors: Kurrle Dieter , Igel Heiner , Ferreira Ana M. G. , Wassermann Joachim , Schreiber Ulrich
Published: February 2010

We investigate the possibility of determining local dispersion characteristics of Love waves using seismograms of transverse acceleration and rotation rate around a vertical axis recorded at the same site. Assuming plane‐wave propagation, phase velocity information is contained in the frequency‐dependent amplitude ratio of the two different types of ground motion. We perform tests of this method using real measurements from a ring laser system and a broadband seismometer at the geodetic observatory Wettzell in southeast Germany as well as synthetic seismograms computed by normal mode summation. While general dispersion characteristics can be recovered, we show that the contribution of overtones impedes the use of this method for structural inversion. To extract the structural information contained in collocated measurements of rotations and translations, a full waveform inversion is necessary.
Brain Glucose Overexposure and Lack of Acute Metabolic Flexibility in Obesity and Type 2 Diabetes: A PET-[18F]FDG Study in Zucker and ZDF Rats
Authors: Liistro Tiziana , Guiducci Letizia , Burchielli Silvia , Panetta Daniele , Belcari Nicola , Pardini Silvia , Del Guerra Alberto , Salvadori Piero A , Iozzo Patricia
Published: February 2010

Brain glucose exposure may complicate diabetes and obesity. We used positron emission tomography with 18F-fluorodeoxyglucose in Zucker obese, diabetic, and control rats to determine the contributions of blood glucose mass action versus local mechanisms in regulating central glucose disposal in fasted and acutely glucose-stimulated states, and their adaptations in obesity and diabetes. Our study data indicate that brain glucose uptake is dependent on both local and mass action components, and is stimulated by acute glucose intake in healthy rats. In diseased animals, the organ was chronically overexposed to glucose, due to high fasting glucose uptake, almost abolishing the physiologic response to glucose loading.
SBML Level 3 Package Proposal: Flux
Authors: Bergmann Frank , Olivier Brett
Published: February 2010

This document describes an easy to implement package for storing information related to flux balance analysis of SBML Level 3 models (the FBA package). In addition,we provide an example of how this package may be implemented and used as a SBML Level 2 annotation.
Rho GTPases: regulation of cell polarity and growth in yeasts
Authors: Perez Pilar , Rincón Sergio A.
Published: February 2010

Eukaryotic cells display a wide range of morphologies important for cellular function and development. A particular cell shape is made via the generation of asymmetry in the organization of cytoskeletal elements, usually leading to actin localization at sites of growth. The Rho family of GTPases is present in all eukaryotic cells, from yeast to mammals, and their role as key regulators in the signalling pathways that control actin organization and morphogenetic processes is well known. In the present review we will discuss the role of Rho GTPases as regulators of yeasts' polarized growth, their mechanism of activation and signalling pathways in Saccharomyces cerevisiae and Schizosaccharomyces pombe. These two model yeasts have been very useful in the study of the molecular mechanisms responsible for cell polarity. As in other organisms with cell walls, yeast's polarized growth is closely related to cell-wall biosynthesis, and Rho GTPases are critical modulators of this process. They provide the co-ordinated regulation of cell-wall biosynthetic enzymes and actin organization required to maintain cell integrity during vegetative growth.
Status report of the Dresden EBIS/EBIT developments
Authors: Zschornack G. , Grossmann F. , Kentsch U. , Ovsyannikov V. P. , Ritter E. , Schmidt M. , Thorn A. , Ullmann F.
Published: February 2010

We give an overview about latest developments and measurements with the Dresden electron beam ion source family as compact and economically working table-top sources of highly charged ions. The ion sources are potential tools for various applications such as for use in combination with accelerators in medical particle therapy, as charge breeder or ion trap injector, as ion sources for a new generation of focused ion beam devices and for applications together with time-of-flight secondary mass spectrometers.
Formation of steep, low Schottky-barrier contacts by dopant segregation during nickel silicidation
Authors: Feste S. F. , Knoch J. , Buca D. , Zhao Q. T. , Breuer U. , Mantl S.
Published: February 2010

We present a systematic analysis of arsenic dopant segregation during nickel silicide formation. The slopes and concentrations of the arsenic dopant profiles at the NiSi∕Si interface have been studied as a function of implantation energy, implantation dose, and NiSi thickness. Silicidation induced dopant segregation conserves the dopant slope at the silicide/silicon interface up to NiSi thicknesses of three times the as-implanted peak depth before degrading. Best slopes and highest dopant concentrations are obtained for low implantation energies and thin NiSi layers. We also demonstrate that the steepness of the dopant profile at the NiSi∕Si interface can be significantly improved through a two-step annealing process for NiSi formation. For As, 1keV, 1×1015cm−2, and a 17nm NiSi layer, a NiSi∕Si junction with a dopant slope of 3.2nm/decade has been obtained. An effective Schottky barrier of ΦSB=0.12eV was determined by low temperature measurements of Schottky diodes with 20nm NiSi formed by an optimized annealing process.
Interaction of a high-power laser beam with metal sheets
Authors: Boley C. D. , Cutter K. P. , Fochs S. N. , Pax P. H. , Rotter M. D. , Rubenchik A. M. , Yamamoto R. M.
Published: February 2010

Experiments with a high-power laser beam directed onto thin aluminum sheets, with a large spot size, demonstrate that airflow produces a strong enhancement of the interaction. The enhancement is explained in terms of aerodynamic effects. As laser heating softens the material, the airflow-induced pressure difference between front and rear faces causes the metal to bulge into the beam. The resulting shear stresses rupture the material and remove it at temperatures well below the melting point. The material heating is shown to conform to an elementary model. We present an analytic model of elastic bulging. Scaling with respect to spot size, wind speed, and material parameters is determined.
Spectral modeling of rotating turbulent flows
Authors: Baerenzung J. , Mininni P. D. , Pouquet A. , Politano H. , Ponty Y.
Published: February 2010

A subgrid-scale spectral model of rotating turbulent flows is tested against direct numerical simulations (DNSs). The case of Taylor–Green forcing is considered, a configuration that mimics the flow between two counter-rotating disks as often used in the laboratory. Computations are performed for moderate rotation down to Rossby numbers of 0.03, as can be encountered in the Earth’s atmosphere. We provide several measures of the degree of anisotropy of the small scales and conclude that an isotropic model may suffice at moderate Rossby number. The model, developed previously [J. Baerenzung, H. Politano, Y. Ponty, and A. Pouquet, “Spectral modeling of turbulent flows and the role of helicity,” Phys. Rev. E 77, 046303 (2008)], incorporates eddy viscosity and eddy noise that depend dynamically on the index of the energy spectrum. We show that the model reproduces satisfactorily all large-scale properties of the DNS up to Reynolds numbers of ∼104 and for long times after the onset of the inverse cascade of energy; it is also shown to behave better than either the Chollet–Lesieur eddy viscosity model [J. P. Chollet and M. Lesieur, “Parametrization of small scales of three-dimensional isotropic turbulence utilizing spectral closures,” J. Atmos. Sci. 38, 2747 (1981)] or an under-resolved DNS.
Dynamic behavior of tungsten carbide and alumina filled epoxy composites
Authors: Vogler T. J. , Alexander C. S. , Wise J. L. , Montgomery S. T.
Published: February 2010

The dynamic behavior of a tungsten carbide filled epoxy composite is studied under planar loading conditions. Planar impact experiments were conducted to determine the shock and wave propagation characteristics of the material. Its stress-strain response is very close to a similar alumina filled epoxy studied previously, suggesting that the response of the composite is dominated by the compliant matrix material. Wave propagation characteristics are also similar for the two materials. Magnetically driven ramp loading experiments were conducted to obtain a continuous loading response which is similar to that obtained under shock loading. Spatially resolved interferometry was fielded on one experiment to provide a quantitative measure of the variability inherent in the response of this heterogeneous material. Complementing the experiments, a two-dimensional mesoscale model in which the individual constituents of the composite are resolved was used to simulate its behavior. Agreement of the predicted shock and release wave velocities with experiments is excellent, and the model is qualitatively correct on most other aspects of behavior.
Lateral ordering, strain, and morphology evolution of InGaAs/GaAs(001) quantum dots due to high temperature postgrowth annealing
Authors: Riotte M. , Fohtung E. , Grigoriev D. , Minkevich A. A. , Slobodskyy T. , Schmidbauer M. , Metzger T. H. , Hu D. Z. , Schaadt D. M. , Baumbach T.
Published: February 2010

The effect of postgrowth annealing on shape and ordering of a single layer of InGaAs/GaAs(001) quantum dots is investigated by three dimensional grazing incidence small angle x-ray scattering. A transition from disordered dots to two-dimensional lateral ordering is found. This transition is accompanying a quantum dot shape transformation. Grazing incidence diffraction measurements relate the observed ordering type to strain driven self organization. The role of different growth conditions leading to lateral correlation is discussed by comparing the results to recent experimental achievements in the field.
Electron beam ion source and electron beam ion trap (invited)
Authors: Becker Reinard , Kester Oliver
Published: February 2010

The electron beam ion source (EBIS) and its trap variant [electron beam ion trap (EBIT)] celebrated their 40th and 20th anniversary, respectively, at the EBIS/T Symposium 2007 in Heidelberg. These technologically challenging sources of highly charged ions have seen a broad development in many countries over the last decades. In contrast to most other ion sources the recipe of improvement was not “sorcery” but a clear understanding of the physical laws and obeying the technological constraints. This review will report important achievements of the past as well as promising developments in the future.
Local conductivity and electric field analysis of Ag-based conductive adhesive by transmission electron microscopy
Authors: Kawamoto N. , Murakami Y. , Shindo D.
Published: February 2010

The conduction mechanism in Ag-based conductive adhesive, which has attracted the attention of researchers, has been intensively studied by the in situ observations of transmission electron microscopy (TEM) and by using special methods that employ the use of microprobes; Ag-based conductive adhesive is considered as an alternative to Pb-free solders. A current versus voltage (I-V) curve measured by using a microscope exhibited peculiar fluctuations, which implied an irreversible change in the internal structure of a cured adhesive. TEM observations showed a local shape change in Ag agglomerations, such as the formation of small horns, in a sample that was subjected to a large electric current of 1 μA. Electron holography data, which revealed the inhomogeneous distribution of equipotential lines in the sample, also implied an essential role of morphological change in the conduction properties of Ag-based conductive adhesive.
Electronic and hole spectra of layered systems of cylindrical rod arrays: Solar cell application
Authors: Kłos J. W. , Krawczyk M.
Published: February 2010

We have computed the electronic and hole spectra of a three-dimensional superlattice consisting of layers of GaAs rods of finite height arranged in a hexagonal lattice and embedded in an AldGa1−dAs matrix, alternating with spacer layers of homogeneous AlAs. The spectra are calculated in the envelope function approximation, with both light-hole and heavy-hole subbands and hole spin degeneracy taken into account. The application of thick spacers allows to investigate the band structure of isolated layers of cylindrical rods. We estimate the ultimate efficiency of solar energy conversion in a solar cell based on an array of cylindrical quantum dots versus the dot height, and determine the optimal value of this parameter.
Large-scale graphitic thin films synthesized on Ni and transferred to insulators: Structural and electronic properties
Authors: Cao Helin , Yu Qingkai , Colby Robert , Pandey Deepak , Park C. S. , Lian Jie , Zemlyanov Dmitry , Childres Isaac , Drachev Vladimir , Stach Eric A. , Hussain Muhammad , Li Hao , Pei Steven S. , Chen Yong P.
Published: February 2010

We present a comprehensive study of the structural and electronic properties of ultrathin films containing graphene layers synthesized by chemical vapor deposition based surface segregation on polycrystalline Ni foils then transferred onto insulating SiO2/Si substrates. Films of size up to several mm’s have been synthesized. Structural characterizations by atomic force microscopy, scanning tunneling microscopy, cross-sectional transmission electron microscopy (XTEM), and Raman spectroscopy confirm that such large-scale graphitic thin films (GTF) contain both thick graphite regions and thin regions of few-layer graphene. The films also contain many wrinkles, with sharply-bent tips and dislocations revealed by XTEM, yielding insights on the growth and buckling processes of the GTF. Measurements on mm-scale back-gated transistor devices fabricated from the transferred GTF show ambipolar field effect with resistance modulation ∼50% and carrier mobilities reaching ∼2000 cm2/V s. We also demonstrate quantum transport of carriers with phase coherence length over 0.2 μm from the observation of two-dimensional weak localization in low temperature magnetotransport measurements. Our results show that despite the nonuniformity and surface roughness, such large-scale, flexible thin films can have electronic properties promising for device applications.
Tunable electrical superlattices in periodically gated bilayer graphene
Authors: Dragoman D. , Dragoman M. , Plana R.
Published: February 2010

The paper demonstrates that a single flake of bilayer graphene patterned with a periodic array of metallic gate electrodes behaves like a programmable superlattice formed by heterostructures of type I, II, or III, depending on the dc gate voltage values. The engineering of the width and position of the band gap in each region is performed only by tuning the dc voltages applied on the gate electrodes. Such a single programmable superlattice on bilayer graphene could replace the existing superlattices that require different semiconductor materials for each heterostructure type.
Charging effect on electroluminescence performance of nc-Si/a-SiO2 films
Authors: Zhang Wa Li , Zhang Sam , Yang Ming , Liu Zhen , Chen Tu Pei
Published: February 2010

Silicon nanocrystals are synthesized by reactive magnetron sputtering to distribute throughout the gate oxide layer. Electroluminescence (EL) from amorphous silicon dioxide (a-SiO2) film embedded with Si nanocrystals (nc-Si) has been studied under various gate voltages. Both the integrated EL intensity and the gate current first increase and then decrease with increasing gate voltage. The decrease in EL intensity is ascribed to the charging up of the nc-Si associated trapping centers. The EL intensity can be partially recovered by application of positive electric stress to release part of the trapped charges.
An efficient in-plane energy level shift in InAs/InGaAsP/InP quantum dots by selective area growth
Authors: Nguyen D. H. , Park J. , Jang Y. D. , Lee D. , Pyun S. H. , Jeong W. G. , Jang J. W.
Published: February 2010

Selective area growth was adopted to grow high-quality quantum dots (QDs) of different energy levels on the same plane at 1.5 μm. At room temperature, the photoluminescence (PL) peak of InAs/InGaAsP QDs on InP substrate was shifted from 1445 to 1570 nm for sample 1 (from 1385 to 1485 nm for sample 2) in a plane, with a PL intensity comparable to those of regular samples grown without dielectric patterns. The dot shape was a round dome, with the density reduced by 28% and the height increased by 17%. Time-resolved PL indicated that the selectively grown QDs behaved similarly to regular QDs. These results open up a practical method for in-plane integration of QD devices.
Majority carrier type conversion in solution-processed organic transistors and flexible complementary logic circuits
Authors: Ribierre J. C. , Watanabe S. , Matsumoto M. , Muto T. , Aoyama T.
Published: February 2010

We report on the realization of high performance solution-processed ambipolar organic transistors based on a quinoidal oligothiophene derivative. The devices show hole and electron field-effect mobilities in air as high as 0.1 and 0.006 cm2 V−1 s−1, respectively, and can be converted from ambipolar p-type dominant to n-type transistors by thermal annealing. The conversion of the majority carrier type is assigned to strong variations in molecular packing. The demonstration of complementary flexible inverters suggests an effective strategy for patterning lateral pn-bipolar structures in solution-processed thin films made from a monolithic ambipolar organic semiconductor.
Effect of deposition temperature on surface morphology and magnetic properties in epitaxial CoFe2O4 thin films deposited by metal organic chemical vapor deposition
Authors: Pan M. , Bai G. , Liu Y. , Hong S. , Dravid V. P. , Petford-Long A. K.
Published: February 2010

We have successfully grown epitaxial CoFe2O4 (CFO) thin film on SrTiO3 by metal organic chemical vapor deposition. In order to understand the surface structure and its correlation with magnetic properties, CFO thin films were deposited at a range of deposition temperatures. As the deposition temperature is decreased, a huge effect on film morphology and surface roughness is observed, resulting from a change in the size and density of the crystal nuclei. These changes to grain structure and surface roughness modify the energy landscape of the films and are major contributors to the change in magnetic properties as a function of deposition temperature: the direction of the easy axis is aligned in-plane at lower deposition temperatures and lower anisotropy between different directions is observed in the rough films grown at high temperature.
Thickness of the rim of an expanding lamella near the splash threshold
Authors: de Ruiter Jolet , Pepper Rachel E. , Stone Howard A.
Published: February 2010

The evolution of the ejected liquid sheet, or lamella, created after impact of a liquid drop onto a solid surface is studied using high-speed video in order to observe the detailed time evolution of the thickness of the rim of the lamella. Since it has been suggested that splashing behavior is set at very early times after impact, we study early times up to D0/U0, where D0 and U0 are the diameter and speed of the impacting drop, respectively, for different liquid viscosities and impact speeds below the splashing threshold. Within the regime of our experiments, our results are not consistent with the idea that the lamella rim grows similar to the boundary layer thickness. Rather, we find that the rim thickness is always much larger than the boundary layer thickness, and that the rim thickness decreases with increasing impact speed. For lower impact speeds, the increase in the rim thickness is consistent with a t response over the limited time range available, but the dependence is not simply proportional to ν, where ν is the kinematic viscosity, and there is a strong dependence of the rim thickness on the impact speed U0. Scaling of the rim height using a balance of inertial and surface tension forces provides some collapse of the data at lower impact speeds. We also observe an unusual plateau behavior in thickness versus time at higher impact speeds as we approach the splash threshold.
Clustered frequency analysis of shear Alfvén modes in stellarators
Authors: Spong D. A. , D’Azevedo E. , Todo Y.
Published: February 2010

The shear Alfvén spectrum in three-dimensional configurations, such as stellarators and rippled tokamaks, is more densely populated due to the larger number of mode couplings caused by the variation in the magnetic field in the toroidal dimension. This implies more significant computational requirements that can rapidly become prohibitive as more resolution is requested. Alfvén eigenfrequencies and mode structures are a primary point of contact between theory and experiment. A new algorithm based on the Jacobi–Davidson method is developed here and applied for a reduced magnetohydrodynamics model to several stellarator configurations. This technique focuses on finding a subset of eigenmodes clustered about a specified input frequency. This approach can be especially useful in modeling experimental observations, where the mode frequency can generally be measured with good accuracy and several different simultaneous frequency lines may be of interest. For cases considered in this paper, it can be a factor of 102–103 times faster than more conventional methods.