bluuebunny/crossref_metadata_2025 huggingface dataset:
PVD – Eine Erfolgsgeschichte mit Zukunft
Authors: Bobzin K. , Bagcivan N. , Immich P. , Pinero C. , Goebbels N. , Krämer A.
Published: January 2008

PVD‐Schichten (PVD: Physical Vapour Deposition) in Schichtdickenbereichen von wenigen Nanometern bis einigen Mikrometern sind aus den Ingenieurwissenschaften nicht mehr wegzudenken. PVD‐Schichten begegnen uns überall im täglichen Leben, als Datenspeicher auf CDs/DVDs, als Wärmedämmung auf Auto‐ und Architekturglas, als Diffusionsbarriere bei Lebensmittelverpackungen oder als dekorative Schichten für Schmuck, Armaturen und Accessoires.

In den letzten 3 Jahrzehnten haben sich PVD‐Schichten in einer Vielzahl von technischen Anwendungen zum Verschleißschutz und zur Reibminderung etablieren können. Neben der eigentlichen Schichtentwicklung, zunächst für Werkzeuge später auch für Bauteile, wurden in der Vergangenheit zahlreiche Erfahrungen zur methodischen Produktentwicklung gesammelt. Die Oberfläche als modernes Konstruktionselement steht dabei noch ganz am Anfang des Möglichen. Die bisher erreichbare Leistungsfähigkeit beschichteter Bauteile kann noch erheblich gesteigert werden, wenn das tribologische System bestehend aus Schicht‐, Substratwerkstoff und Zwischenstoff, wie z. B. Schmiermittel, unter Berücksichtigung der Mikro‐ und Makrogeometrie für eine spezielle Anwendung optimal ausgelegt werden.

Exemplarisch wird an einem Anwendungsbeispiel aus dem Sonderforschungsbereich (SFB) 442 „umweltverträgliche Tribosysteme”︁ der RWTH Aachen die Umsetzung von Ergebnissen aus der Grundlagenforschung bis hin zur industriellen Anwendung vorgestellt und an der industriellen PVD‐Marktentwicklung gespiegelt. In diesem Beispiel wird die Entwicklungsmethodik der Oberflächentechnik in der Prozesskette von der Fertigung bis zum Einsatztest des neuen Produktes dargestellt.
High‐resolution peripheral vein bypass graft wall studies using high sampling efficiency inner volume 3D FSE
Authors: Mitsouras Dimitris , Mulkern Robert V. , Owens Christopher D. , Conte Michael S. , Ersoy Hale , Luu Tuan M. , Whitmore Amanda G. , Creager Mark A. , Rybicki Frank J.
Published: January 2008

A 3D inner‐volume fast spin echo (3D IV‐FSE) sequence was developed for ECG‐gated, black‐blood, T1‐ and T2‐weighted vessel wall imaging of peripheral vein bypass grafts (PVBG). The sequence utilizes nonselective refocusing excitations to minimize echo spacings and a highly selective IV excitation scheme to minimize the need for oversampling of z‐encode slice selections. The method was tested in eight PVBG patients who also underwent 2D FSE graft imaging. High‐quality 3D imaging was achieved in all subjects, with significant spatial resolution and volume coverage gains compared to the more conventional 2D FSE sequences normalized for signal‐to‐noise ratios (SNRs) and scan times. Compared to previously proposed 3D IV‐FSE methods, nonselective refocusing resulted in a more than 20% FSE echo train sampling efficiency increase while the use of highly selective IV excitation resulted in a 30% improvement in slice oversampling efficiency. Magn Reson Med, 2008. © 2008 Wiley‐Liss, Inc.
Metabolic changes in the thalamus after spinal cord injury followed by proton MR spectroscopy
Authors: Likavčanová Katarína , Urdzíková Lucia , Hájek Milan , Syková Eva
Published: January 2008

Our study followed the changes in thalamic nuclei metabolism, hindlimb sensitivity to thermal stimulation, and locomotor function after spinal cord injury (SCI). MR spectroscopy (MRS) was used to examine the thalamic nuclei of rats 1 day before and 1, 3, 6, and 15 days after SCI or sham surgery. All animals were tested before MRS measurements for motor performance and thermal sensitivity. SCI induced by balloon compression caused complete paraplegia from the first to third day, followed by partial functional recovery during the second week. MRS revealed an increase in N‐acetylaspartate (NAA) concentration in the thalamic nuclei on the first day after SCI, which decreased by the third day. The data also showed an increase in inositol (Ins), glutamate, and creatine (Cr) concentrations on the third day postinjury; the Ins concentration remained elevated on the sixth day. In sham‐operated animals an increase in NAA concentration was observed on the sixth and fifteenth days after surgery and an increase in Cr concentration on the third day. A positive correlation between Ins concentration and hindlimb sensitivity in both SCI and sham‐operated animals suggests changes in glial activity, while changes in NAA levels may indicate the response of thalamic neuronal cells to injury. Magn Reson Med, 2008. © 2008 Wiley‐Liss, Inc.
Structural materials underpinning functional materials: teaching old dogs new tricks
Authors: MacDonald William A
Published: January 2008

‘Structural’ polymers are finding new applications underpinning new technology developments based on functional polymers. This paper discusses the use of polyester films as base substrates for flexible electronic applications based on conjugated polymers and low‐temperature hydrogenated amorphous silica processing, and discusses the challenges involved in successfully developing substrates ‘fit for purpose’. Copyright © 2008 Society of Chemical Industry
Molecular weight dependence of phase behavior of PEO/P(EO‐b‐DMS) blends: Application of Sanchez‐Lacombe lattice fluid theory
Authors: Li Hongfei , Jiang Shichun , Sun Zhaoyan , An Lijia
Published: January 2008

Molecular weight dependence of phase separation behavior of the Poly (ethylene oxide) (PEO)/Poly(ethylene oxide‐block‐dimethylsiloxane) (P(EO‐b‐DMS)) blends was investigated by both experimental and theoretical methods. The cloud point curves of PEO/P(EO‐b‐DMS) blends were obtained by turbidity method. Based on Sanchez‐Lacombe lattice fluid theory (SLLFT), the adjustable parameter, $ {{\varepsilon _{12}^\ast } \mathord{\left/ {\vphantom {{\varepsilon _{12}^* } k}} \right. \kern-\nulldelimiterspace} k} $ (quantifying the interaction energy between different components), was evaluated by fitting the experimental data in phase diagrams. To calculate the spinodals, binodals, and the volume changes of mixing for these blends, three modified combining rules of the scaling parameters for the block copolymer were introduced. The calculated binodals with those modified combining rules show good agreement with the experimental data. Furthermore, the calculated volume changes during mixing decrease with increasing molecular weight of PEO, and the relationship between the volume changes and temperature is quite different for the mixtures with different molecular weight of PEO. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 452–459, 2008
Sitagliptin: first DPP‐4 inhibitor to treat type 2 diabetes
Authors: Chaplin Steve , Krentz Andrew
Published: January 2008

Sitagliptin (Januvia) is the first of a new class of drugs in the treatment of type 2 diabetes. Here, Steve Chaplin presents the clinical data relating to its efficacy and adverse effects, and Dr Krentz comments on its potential place in the treatment of type 2 diabetes. Copyright © 2008 Wiley Interface Ltd
Clinical Knowledge Summaries — supporting better prescribing
Authors: Smart Sharon
Published: January 2008

Clinical Knowledge Summaries is a new source of clinical knowledge enabling healthcare professionals to make evidencebased decisions about the management of over 500 clinical situations commonly encountered in general practice. Copyright © 2008 Wiley Interface Ltd
An exploratory comparative study of volatile compounds in exhaled breath and emitted by skin using selected ion flow tube mass spectrometry
Authors: Turner Claire , Parekh Bhavin , Walton Christopher , Španěl Patrik , Smith David , Evans Mark
Published: January 2008

Selected ion flow tube mass spectrometry (SIFT‐MS) has been used to carry out a pilot parallel study on five volunteers to determine changes occurring in several trace compounds present in exhaled breath and emitted from skin into a collection bag surrounding part of the arm, before and after ingesting 75 g of glucose in the fasting state. SIFT‐MS enabled real‐time quantification of ammonia, methanol, ethanol, propanol, formaldehyde, acetaldehyde, isoprene and acetone. Following glucose ingestion, blood glucose and trace compound levels were measured every 30 min for 2 h. All the above compounds, except formaldehyde, were detected at the expected levels in exhaled breath of all volunteers; all the above compounds, except isoprene, were detected in the collection bag. Ammonia, methanol and ethanol were present at lower levels in the bag than in the breath. The aldehydes were present at higher levels in the bag than in breath. The blood glucose increased to a peak about 1 h post‐ingestion, but this change was not obviously correlated with temporal changes in any of the compounds in breath or emitted by skin, except for acetone. The decrease in breath acetone was closely mirrored by skin‐emitted acetone in three volunteers. Breath and skin acetone also clearly change with blood glucose and further work may ultimately enable inferences to be drawn of the blood glucose concentration from skin or breath measurements in type 1 diabetes. Copyright © 2008 John Wiley & Sons, Ltd.
The influence of prior knowledge on viewing and interpreting graphics with macroscopic and molecular representations
Authors: Cook Michelle , Wiebe Eric N. , Carter Glenda
Published: January 2008

Previous research has indicated that the use of multiple representations with macroscopic and molecular features can improve conceptual understanding; however, the influence of prior knowledge of the domain cannot be overlooked. Using eye‐tracking technology and sequential analysis, this study investigated how high school students (n = 54) with different levels of prior knowledge transitioned among the macroscopic and molecular representations of the selected cell transport graphics. The results indicated that high prior knowledge students transitioned more frequently between the molecular representations, whereas low prior knowledge students transitioned more frequently between the macroscopic representations. These findings suggest that students with high prior knowledge distributed their visual attention on conceptually relevant features, whereas low prior knowledge students focused on surface features. In addition, low prior knowledge students transitioned more frequently between macroscopic and molecular representations, suggesting that these students were experiencing more difficulty as they were coordinating the representations. Because these students were using surface features to create linkages between the representations, they were unable to understand the underlying themes. More research on the differences in the distribution of visual attention among learners can provide further insight as to the difficulties low prior knowledge students face when interpreting multiple representations. © 2008 Wiley Periodicals, Inc. Sci Ed 92:848–867, 2008
Probabilistic Analysis of Process Economics
Authors: Deissenboeck Florian , Pizka Markus
Published: January 2008

The economic benefit of a certain development process or particular activity is usually unknown and indeed hard to predict. However, the cost‐effectiveness of process improvements is of paramount importance and the question how profitable certain activities are needs to be answered. Within a large‐scale commercial organization, we were challenged with the task to quantify the economic benefit of isolated test and development environments. To answer this question, we defined a generic process model based on absorbing Markov chains that allows the analyzation of the economic benefit of software process variations. This model exposes conflicts between process steps and reiterations of development activities and thereby provides a highly flexible tool for the investigation of the effects of changes to a development process on its overall performance. This model was used to predict the impact of isolated testing on the overall effort and duration of projects. The results obtained correspond well with the perception of experienced developers and gives a detailed explanation for the effects. Besides this, it can be used to analyze various other economic aspects of software development processes and yields an interesting alternative for cost estimation. Copyright © 2008 John Wiley & Sons, Ltd.
Continuous process improvement at a large software organization
Authors: Malheiros Viviane , Paim Fábio Rilston , Mendonça Manoel
Published: January 2008

Designing software processes for large enterprises is a hard task, but evolving this process can be even harder. As large companies increasingly invest in software process improvement, they have to face typical problems regarding software process evolution within such environments in order to guarantee their software process survival. This article describes experiences and lessons learned at Serpro, the largest government owned software company in Latin America, while defining its organizational standard software process and fostering its continuous evolution. Copyright © 2008 John Wiley & Sons, Ltd.
Quality assurance for TTCN‐3 test specifications
Authors: Neukirchen Helmut , Zeiss Benjamin , Grabowski Jens , Baker Paul , Evans Dominic
Published: January 2008

Comprehensive testing of modern communication systems often requires large and complex test suites, which have to be maintained throughout the system life cycle. Industrial experience, with those written using the standardized Testing and Test Control Notation (TTCN‐3), has shown that this maintenance is a non‐trivial task and its burden can be reduced by means of appropriate concepts and tool support. To this aim, Motorola has collaborated with the University of Göttingen to develop TRex, an open‐source TTCN‐3 development environment, which notably provides suitable metrics and refactorings to enable the assessment and automatic restructuring of test suites. This article presents concepts like metrics and refactoring for the quality assurance of TTCN‐3 test suites and their implementation provided by the TRex tool. These means make it far easier to construct and maintain TTCN‐3 tests that are concise and optimally balanced with respect to maintainability quality characteristics. Copyright © 2008 John Wiley & Sons, Ltd.
An urban Italian study on emergency room utilisation by immigrants suffering from mental disorders in Rome, 2000–2004
Authors: Gaddini A. , Franco F. , Biscaglia L. , Di Lallo D.
Published: January 2008

Purpose

To compare Emergency Room (ER) utilisation by subjects diagnosed as suffering from a mental disorder, who were born in Strong Migratory Pressure Countries (SMPC) or in Italy. To evaluate the predictors of admission to psychiatric and to non-psychiatric wards.

Method

Data collected from Information System of Emergency Rooms were analysed. ER contacts in the years 2000–2004 pertaining to subjects who received a psychiatric diagnosis (ICD9-CM codes), and who were born in SMPC or in Italy were examined. “Contacts” included a total of 68,867 assessments made in the ER of all general hospitals in Rome having an acute psychiatric ward. Gender, age and clinical information on SMPC-born and Italian-born patients were compared. A multinomial logistic regression analysis was performed in order to determine risk factors for admission to a psychiatric or to a non-psychiatric ward.

Results

At the end of follow-up, 11.7% of ER contacts concerned patients born in SMPC. Compared to the Italian-born group, these patients were younger and received more frequently a diagnosis of “Alcohol and substance abuse and dependencies”, while admissions to a psychiatric ward were significantly less common.

Conclusion

Monitoring health service utilisation may provide relevant information for the delivery of culturally sensitive mental health services.
Rett syndrome in adults with severe intellectual disability: Exploration of behavioral characteristics
Authors: Matson Johnny L. , Dempsey Timothy , Wilkins Jonathan
Published: January 2008

Rett syndrome is a genetically linked form of autism spectrum disorder (ASD) accompanied by intellectual disability (ID). The disorder is also characterized by cardiorespiratory dysregulation, disturbance in muscle tone, reduced brain growth and scoliosis. Over 300 studies have been published on the disorder, most of which has focused on identification of causative factors, which appears to be the result of mutations of gene MECP2. Rarely have adults with Rett syndrome been studied, and behavioral characteristics in these individuals are largely unknown. The present study aimed to extend what little is known about behavioral characteristics of Rett syndrome in adults, with particular emphasis on social, communicative, and adaptive behavior. Rett syndrome adults with severe ID were matched to autistic adults with ID and ID only controls. The implications of these data for more fully describing and diagnosing the condition in adults are discussed.
Effectiveness of cryotherapy treatment for cervical intraepithelial neoplasia
Authors: Luciani Silvana , Gonzales Miguel , Munoz Sergio , Jeronimo Jose , Robles Sylvia
Published: January 2008

Objective

To assess the effectiveness of cryotherapy treatment delivered by general practitioners in primary care settings, as part of a screen‐and‐treat approach for cervical cancer prevention.

Method

Women aged between 25 and 49 years residing in San Martin, Peru, who were positive on visual inspection screening were treated, if eligible, with cryotherapy following biopsy. At 12 months post cryotherapy treatment the participants were evaluated for treatment effectiveness and examined by visual inspection and Papanicolaou test and, if positive, referred to a gynecologist for colposcopy and biopsy.

Results

Cryotherapy treatment was performed for 1398 women; of these, 531 (38%) had a histology result of cervical intraepithelial neoplasia (CIN). Cryotherapy effectively cured CIN in 418 (88%) women, including 49 (70%) women with a baseline diagnosis of CIN 3.

Conclusion

Cryotherapy is an effective treatment for cervical precancerous lesions; it can easily be administered by general practitioners in primary care settings following visual inspection screening.
Arctic shipping guidelines: towards a legal regime for navigation safety and environmental protection?
Authors: Jensen Øystein
Published: January 2008

With the International Polar Year (IPY) having commenced in March 2007, key issues relating to the polar regions are again in focus. This article reviews one central legal issue re-emerging in the Arctic: global regulation of safety standards for international shipping. The ‘Guidelines for ships operating in Arctic ice-covered waters’ are examined, with a view to the probable expansion of shipping in the Arctic in near future. Following an introduction to navigational issues within the Arctic context, the article describes how the guidelines came into being, and then analyses key elements and structure of the regulations and shortfalls of today's arrangements. The possible relevance of the guidelines to the Antarctic is also discussed briefly. Finally, the article inquires into the key repercussions of introducing binding regulations.
The United States 2002 Unified Command Plan: Antarctica and the areas of responsibility of military commanders
Authors: Dodds Klaus , Hemmings Alan D.
Published: January 2008

In October 2002, following the 11 September 2001 attacks on the United States, the Unified Command Plan (UCP), that sets out the geographical responsibilities of combatant commanders, was revised with regard to their areas of responsibility. Accompanying these changes was a map, which detailed the geographical boundaries of the US Northern, Pacific, Southern, European and Central Commands. The map indicated that two of these Commands, Southern and European Command stretched as far south as the Antarctic coastline while a third (Pacific) not only did that but also included the entire Antarctic continent. In 2007, a new Africa Command comprising the southern part of European Command, was instituted and this, too, stretched to the Antarctic coastline. This note briefly considers some of the implications that might follow from these changes to the UCP and highlights logistical patterns, search and rescue matters and the question of the demilitarisation of Antarctica.
Methodology for calculating a country's need for positron emission tomography scanners
Authors: Cleemput Irina , Camberlin Cécile , Van den Bruel Ann , Ramaekers Dirk
Published: January 2008

Objectives:The aim of this study was to develop a methodology for calculating the need for positron emission tomography (PET) scanners in a country and illustrate this methodology for Belgium.

Methods:First, levels of evidence were assigned to PET in different indications according to a standard hierarchical classification system. The level reached depends on whether there is evidence on diagnostic accuracy, impact on diagnostic thinking, therapeutic impact, impact on patient outcomes, or cost-effectiveness. Second, the number of patients eligible for PET for each indication was derived from a registry of PET. Third, the number of PET scanners needed in Belgium was estimated for different baseline hypotheses about maximum annual capacity of a scanner and the minimally required level of evidence.

Results:The number of PET scanners needed crucially depends on the level of evidence considered acceptable for the implementation of PET: the higher the level of evidence required, the lower the number of PET scanners needed. Belgium needs at least three and at most ten PET scanners. This contrasts with the thirteen currently approved.

Conclusions:Scientific evidence and information on the eligible population for a specific procedure are crucial elements for policy makers who wish to make evidence-based decisions about programming and planning of heavy medical equipment.
Systematic review of the impact of endoscopic ultrasound on the management of patients with esophageal cancer
Authors: Dyer Suzanne M. , Levison Dane B. , Chen Robert Y. , Lord Sarah J. , Blamey Stephen
Published: January 2008

Objectives:Although endoscopic ultrasound (EUS) staging of esophageal cancer is established in clinical practice, high-quality evidence about its impact on patient outcomes is not available. This study aims to determine the impact of EUS for esophageal cancer staging on patient management and survival.

Methods:A systematic review was conducted using Medline, PreMedline, Embase, and The Cochrane Library. Included studies were (i) comparative studies reporting survival following EUS esophageal cancer staging, (ii) therapeutic impact studies reporting change in patient management following EUS. The quality of included studies was critically appraised.

Results:One systematic review, five studies reporting therapeutic impact, and two studies reporting patient survival were identified. The design and quality of the therapeutic impact studies varied widely. Management changed in 24–29 percent of patients following EUS staging of esophageal cancer (two studies). No studies provided data on the avoidance of surgery for this indication. One retrospective cohort study with historical control found EUS staging of esophageal cancer improved patient survival; a second study with similar design limitations did not find a survival benefit for EUS staging in patients undergoing resection. These studies had a high potential for bias, limiting the value of these findings.

Conclusions:Two studies provided evidence of a change in patient management following EUS for staging esophageal cancer, a higher level of evidence for a clinical benefit than can be obtained from accuracy studies alone. This evidence contributed to a recommendation for public funding of EUS in staging esophageal cancer in Australia.
Cost-effectiveness analysis of Helicobacter pylori screening in prevention of gastric cancer in Chinese
Authors: Xie Feng , Luo Nan , Blackhouse Gord , Goeree Ron , Lee Hin-Peng
Published: January 2008

Objectives:The aim of this study was to evaluate the costs and effectiveness associated with no screening,Helicobacter pyloriserology screening, and the13C-urea breath test (UBT) for gastric cancer in the Chinese population.

Methods:A Markov model simulation was carried out in Singaporean Chinese at 40 years of age (n= 478,500) from the perspective of public healthcare providers. The main outcome measures were costs, number of gastric cancer cases prevented, life-years saved, quality-adjusted life-years (QALYs) gained from the screening age to death, and incremental cost-effectiveness ratios (ICERs), which were compared among the three strategies. The uncertainty surrounding ICERs was addressed by scenario analyses and probabilistic sensitivity analysis using Monte Carlo simulation.

Results: The ICER of serology screening versus no screening was $25,881 per QALY gained (95 percent confidence interval (95 percent CI), $5,700 to $120,000). The ICER of UBT versus no screening was $53,602 per QALY gained (95 percent CI, $16,000 to $230,000). ICER of UBT versus serology screening was $470,000 per QALY gained, for which almost all random samples of the ICERs distributed above $50,000 per QALY.

Conclusions: It cannot be confidently concluded that eitherH pyloriscreening was a cost-effective strategy compared with no screening in all Chinese at the age of 40 years. Nevertheless, serology screening has demonstrated much more potential to be a cost-effective strategy, especially in the population with higher gastric cancer prevalence.
Using the literature to quantify the learning curve: A case study
Authors: Cook Jonathan A. , Ramsay Craig R. , Fayers Peter
Published: January 2008

In the first paragraph in the “Description of Studies” subsection and the sole paragraph of the “Procedure Time” subsection of the “RESULTS” section on page 257 of Volume 23 Number 2 ofInternational Journal of Technology Assessment in Health Care, two tables are listed as “published on the Web site.” However, no link was provided.
CREDIT AND GROWTH UNDER LIMITED COMMITMENT
Authors: AZARIADIS COSTAS , KAAS LEO
Published: January 2008

We consider a linear growth model with idiosyncratic productivity shocks in which producers cannot commit to repay their loans. Borrowing constraints are determined endogenously by the borrowers' incentives to repay, assuming that defaulters lose a share of output and are excluded from future trade in the credit market. We characterize necessary and sufficient conditions for the enforceability of a first-best equilibrium growth path. Weak property rights, impatient producers, and small productivity differentials can make the efficient growth path nonenforceable and lead to an inefficient equilibrium with binding borrowing constraints. For some economies, multiple balanced growth paths coexist.
Pasteurella multocidaand bovine respiratory disease
Authors: Dabo S. M. , Taylor J. D. , Confer A. W.
Published: January 2008

Pasteurella multocidais a pathogenic Gram-negative bacterium that has been classified into three subspecies, five capsular serogroups and 16 serotypes.P. multocidaserogroup A isolates are bovine nasopharyngeal commensals, bovine pathogens and common isolates from bovine respiratory disease (BRD), both enzootic calf pneumonia of young dairy calves and shipping fever of weaned, stressed beef cattle.P. multocidaA:3 is the most common serotype isolated from BRD, and these isolates have limited heterogeneity based on outer membrane protein (OMP) profiles and ribotyping. Development ofP. multocida-induced pneumonia is associated with environmental and stress factors such as shipping, co-mingling, and overcrowding as well as concurrent or predisposing viral or bacterial infections. Lung lesions consist of an acute to subacute bronchopneumonia that may or may not have an associated pleuritis. Numerous virulence or potential virulence factors have been described for bovine respiratory isolates including adherence and colonization factors, iron-regulated and acquisition proteins, extracellular enzymes such as neuraminidase, lipopolysaccharide, polysaccharide capsule and a variety of OMPs. Immunity of cattle against respiratory pasteurellosis is poorly understood; however, high serum antibodies to OMPs appear to be important for enhancing resistance to the bacterium. Currently availableP. multocidavaccines for use in cattle are predominately traditional bacterins and a live streptomycin-dependent mutant. The field efficacy of these vaccines is not well documented in the literature.
Comparison of Metabolic Flux Distributions for MDCK Cell Growth in Glutamine‐ and Pyruvate‐Containing Media
Authors: Sidorenko Yury , Wahl Aljoscha , Dauner Michael , Genzel Yvonne , Reichl Udo
Published: January 2008

In mammalian cell cultures, ammonia that is released into the medium as a result of glutamine metabolism and lactate that is excreted due to incomplete glucose oxidation are both known to essentially inhibit the growth of cells. For some cell lines, for example, hybridoma cells, excreted ammonia also has an effect on product formation. Although glutamine has been generally considered as the major energy source for mammalian cells, it was recently found that various adherent cell lines (MDCK, CHO‐K1, and BHK21) can grow as well in glutamine‐free medium, provided glutamine is substituted with pyruvate. In such a medium the level of both ammonia and lactate released was significantly reduced. In this study, metabolic flux analysis (MFA) was applied to Madin Darby Canine Kidney (MDCK) cells cultivated in glutamine‐containing and glutamine‐free medium. The results of the MFA allowed further investigation of the influence of glutamine substitution with pyruvate on the metabolism of MDCK cells during different growth stages of adherent cells, e.g., early exponential and late contact‐inhibited phase. Pyruvate seemed to directly enter the TCA cycle, whereas most of the glucose consumed was excreted as lactate. Although the exact mechanisms are not clear so far, this resulted in a reduction of the glucose uptake necessary for cellular metabolism in glutamine‐free medium. Furthermore, consumption of ATP by futile cycles seemed to be significantly reduced when substituting glutamine with pyruvate. These findings imply that glutamine‐free medium favors a more efficient use of nutrients by cells. However, a number of metabolic fluxes were similar in the two cultivations considered, e.g., most of the amino acid uptake and degradation rates or fluxes through the branch of the TCA cycle converting α‐ketoglutarate to malate, which is responsible for the mitochondrial ATP synthesis. Besides, the specific rate of cell growth was approximately the same in both cultivations. Thus, the switch from glutamine‐containing to glutamine‐free medium with pyruvate provided a series of benefits without dramatic changes of cellular metabolism.
Antarctic Peninsula mesoscale cyclone variability and climatic impacts influenced by the SAM
Authors: Lubin Dan , Wittenmyer Robert A. , Bromwich David H. , Marshall Gareth J.
Published: January 2008

The frequency of mesoscale cyclones in the Western Antarctic Peninsula (WAP) region during 1991–94 is correlated with the Southern Hemisphere Annular Mode (SAM) index, most strongly during winter and spring. Also, during periods of positive SAM index polarity there is a shift in the storm tracks to favor more east‐bound trajectories, consistent with strengthening of circumpolar westerlies. The presence of mesoscale cyclones is associated with positive near‐surface‐air temperature anomalies in the WAP region year‐round, largest during winter.
Interplanetary shock induced ring current auroras
Authors: Zhang Yongliang , Paxton Larry J. , Zheng Yihua
Published: January 2008

On 21 January 2005, a fast interplanetary (IP) shock compressed the magnetosphere and caused detached auroras (DA) on the dayside, duskside and nightside ionosphere. The DA were detected by three independent FUV instruments: IMAGE/SI‐12, TIMED/GUVI and DMSP/SSUSI. The SI‐12 observations show that the dayside detached aurora (DDA) was located between 60° and 68° Mlat and between 06:00 and 15:00 MLT. It lasted for only ∼2 min. Coincident in situ Polar measurements show that sudden bursts of proton EMIC waves (∼2 min) were associated with the DDA. This provides direct evidence of the link between the EMIC waves and the DDA. The DA in the duskside and nightside appeared once the DDA disappeared. GUVI and SSUSI also observed the DA in the duskside and dayside with more details. Ring current simulations show that ∼10 keV protons with sausage‐shaped spatial distribution of high anisotropy in flux and temperature were the particle source for the duskside and nightside DA. Compression of the magnetosphere appears to be the driver for both of the DDA and dusk/night DA. The nightside DA was observed for the first time during a sudden commencement. To unify the different terminologies, the detached auroras due to precipitating energetic protons from the ring current are called the ring current auroras.
Structured Sun glitter recorded in an ASTER along‐track stereo image of Nam Co Lake (Tibet): An interpretation based on supercritical flow over a lake floor depression
Authors: Matthews J. P. , Yang X.‐D. , Shen J. , Awaji T.
Published: January 2008

Sun glitter and synthetic aperture radar (SAR) remote sensing techniques that respond to the small‐scale textural roughness of water surfaces often reveal a plethora of signatures indicative of the presence of bed formations submerged in shallow water (of depth <30 m), even though the electromagnetic signals employed in such methods are reflected at or near to the water surface. In homogeneous (nonstratified) regimes, these signatures are interpreted on the basis of a causal sequence involving an initial topography‐induced perturbation to a strong background current (of speed nominally >0.4 m s−1), the subsequent formation of surface current gradients (the “straining”) of order 10−3 s−1, and an ensuing local modulation of the centimeter‐scale surface roughness controlling the scattering of both light and radar. Here we consider how the presence of stratification might influence this generative sequence in an analysis of high‐sensitivity Sun glitter observations gathered when the background flow speed and surface current gradients are at least one order of magnitude lower. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) acquired these observations on 22 July 2001 while imaging in along‐track stereo mode from slanted fields of view that encompassed Sun glitter reflected from the surface of Nam Co, a large Tibetan lake that is free from anthropogenic surface‐slick contamination. We interpret a structured Sun glitter feature appearing within a shallow embayment in the northwest of the lake as the surface roughness manifestation of a wake formed by supercritical stratified flow over a localized depression in the lake floor topography.
Ion sources with arc-discharge plasma box driven by directly heated LaB6 electron emitter or cold cathode (invited)
Authors: Ivanov Alexander A. , Davydenko Vladimir I. , Deichuli Petr P. , Shulzhenko Grigori I. , Stupishin Nikolay V.
Published: January 2008

In the Budker Institute, Novosibirsk, an ion source with arc-discharge plasma box has been developed in the recent years for application in thermonuclear devices for plasma diagnostics. Several modifications of the ion source were provided with extracted current ranging from 1to7A and pulse duration of up to 4s. Initially, the arc-discharge plasma box with cold cathode was used, with which pulse duration is limited to 2s by the cathode overheating and sputtering in local arc spots. Recently, a directly heated LaB6 electron emitter was employed instead, which has extended lifetime compared to the cold cathode. In the paper, characteristics of the beam produced with both arrangements of the plasma box are presented.
A new ab initio ground-state dipole moment surface for the water molecule
Authors: Lodi Lorenzo , Tolchenov Roman N. , Tennyson Jonathan , Lynas-Gray A. E. , Shirin Sergei V. , Zobov Nikolai F. , Polyansky Oleg L. , Császár Attila G. , van Stralen Joost N. P. , Visscher Lucas
Published: January 2008

A valence-only (V) dipole moment surface (DMS) has been computed for water at the internally contracted multireference configuration interaction level using the extended atom-centered correlation-consistent Gaussian basis set aug-cc-pV6Z. Small corrections to these dipole values, resulting from core correlation (C) and relativistic (R) effects, have also been computed and added to the V surface. The resulting DMS surface is hence called CVR. Interestingly, the C and R corrections cancel out each other almost completely over the whole grid of points investigated. The ground-state CVR dipole of H2O16 is 1.8676D. This value compares well with the best ab initio one determined in this study, 1.8539±0.0013D, which in turn agrees well with the measured ground-state dipole moment of water, 1.8546(6)D. Line intensities computed with the help of the CVR DMS shows that the present DMS is highly similar to though slightly more accurate than the best previous DMS of water determined by Schwenke and Partridge [J. Chem. Phys. 113, 16 (2000)]. The influence of the precision of the rovibrational wave functions computed using different potential energy surfaces (PESs) has been investigated and proved to be small, due mostly to the small discrepancies between the best ab initio and empirical PESs of water. Several different measures to test the DMS of water are advanced. The seemingly most sensitive measure is the comparison between the ab initio line intensities and those measured by ultralong pathlength methods which are sensitive to very weak transitions.
Entangled electron and nuclear spin states in N15@C60: Density matrix tomography
Authors: Scherer Werner , Mehring Michael
Published: January 2008

Procedures of the preparation and detection of entangled electron-nuclear spin states in N15@C60 by combining electron spin resonance and electron nuclear double resonance pulse techniques are presented. A quantitative evaluation of the complete density matrix is obtained by a special density matrix tomography. All four Bell states of a two qubit subsystem were analyzed and experimental decoherence times are presented. In addition, we estimate a quantum critical temperature of Tq=7.76K for this system at an electron spin resonance frequency of 95GHz.
Rugby-like hohlraum experimental designs for demonstrating x-ray drive enhancement
Authors: Amendt Peter , Cerjan C. , Hinkel D. E. , Milovich J. L. , Park H.-S. , Robey H. F.
Published: January 2008

A suite of experimental designs for the Omega laser facility [Boehly et al., Opt. Commun. 133, 495 (1997)] using rugby and cylindrical hohlraums is proposed to confirm the energetics benefits of rugby-shaped hohlraums over cylinders under optimal implosion symmetry conditions. Postprocessed Dante x-ray drive measurements predict a 12–17eV (23%–36%) peak hohlraum temperature (x-ray flux) enhancement for a 1ns flattop laser drive history. Simulated core self-emission x-ray histories also show earlier implosion times by 200–400ps, depending on the hohlraum case-to-capsule ratio and laser-entrance-hole size. Capsules filled with 10 or 50atm of deuterium (DD) are predicted to give in excess of 1010 neutrons in two-dimensional hohlraum simulations in the absence of mix, enabling DD burn history measurements for the first time in indirect-drive on Omega. Capsule designs with 50atm of DHe3 are also proposed to make use of proton slowing for independently verifying the drive benefits of rugby hohlraums. Scale-5/4 hohlraum designs are also introduced to provide further margin to potential laser-plasma-induced backscatter and hot-electron production.
Auxiliary basis sets for density fitting–MP2 calculations: Nonrelativistic triple-ζ all-electron correlation consistent basis sets for the 3d elements Sc–Zn
Authors: Hill J. Grant , Platts James A.
Published: January 2008

Auxiliary basis sets for density fitting second-order Møller-Plesset perturbation theory (DF-MP2) have been optimized for use with the triple-ζ nonrelativistic all-electron correlation consistent orbital basis sets, cc-pVTZ-NR and aug-cc-pVTZ-NR, for the 3d elements Sc–Zn. The relative error in using these auxiliary basis sets is found to be around four orders of magnitude smaller than that from utilizing triple-ζ orbital basis sets rather than corresponding quadruple-ζ basis sets, in calculation of the correlation energy for a test set of 54 small to medium sized transition metal complexes.
Fully relativistic calculations on the potential energy surfaces of the lowest 23 states of molecular chlorine
Authors: de Macedo Luiz Guilherme M. , de Jong Wibe A.
Published: January 2008

The electronic structure and spectroscopic properties (Re, ωe, ωexe, βe, and Te) of the ground state and the 22 lowest excited states of chlorine molecule were studied within a four-component relativistic framework using the MOLFDIR program package. The potential energy curves of all possible 23 covalent states were calculated using relativistic complete open shell configuration interaction approach. In addition, four component multireference configuration interaction with single and double excitation calculations were performed in order to infer the effects due to dynamical correlation in vertical excitations. The calculated properties are in good agreement with the available experimental data.
Universal phase and force diagrams for a microbubble or pendant drop in static fluid on a surface
Authors: Wei P. S. , Hsiao C. C. , Chen K. Y.
Published: January 2008

Dimensionless three-dimensional universal phase and lift force diagrams of a microbubble (or pendant drop) in static liquid on a solid surface (or orifice) are presented in this work. Microbubble dynamics has been found to play a vital role in mass, momentum, energy, and concentration transfer rates in contemporary micro- and nanosciences and technologies. In this study, dimensionless phase and force diagrams are introduced by utilizing the analytical solutions of the microbubble shape reported in the literature. It shows that phase and force diagrams can be universally specified by two dimensionless independent parameters, Bond number, and contact angle (or base radius). Based on the presence of an inflection point or neck on the microbubble surface, each diagram exhibits three regions. Growth, detachment, and entrapment of a microbubble can be described by path lines in three regions. The corresponding universal total lift forces include hydrostatic buoyancy, difference in gas, and hydrostatic pressures at the base, capillary pressure, as well as surface tension induced by the variation of circumference, which has not been treated in the literature so far. In the absence of viscous stress and Marangoni force, the total lift force equals surface tension induced by the variation of circumference. The latter can be an attaching or lifting force, depending on whether the state in the distinct regions and contact angle is less than or greater than a critical angle. The critical angle, which is slightly less than the inclination angle at the inflection point, is decreased with increasing Bond number.
Effect of pulsed laser irradiation on the structural and the magnetic properties of NiMn∕Co exchange bias system
Authors: Mohanan Senthilnathan , Diebolder Rolf , Hibst Raimund , Herr Ulrich
Published: January 2008

We report about the influence of pulsed laser irradiation on the structural and magnetic properties of NiMn∕Co thin films. Rocking curve measurements showed a significant improvement of the (111) texture of NiMn after laser irradiation which was accompanied by grain growth. We have studied the ordering transition in as-prepared and irradiated (laser fluence of 0.15J∕cm2) samples during subsequent annealing. The onset of the fcc to fct phase transformation occurs at 325°C irrespective of laser irradiation. Exchange bias fields for the laser irradiated samples are higher than those of the as-prepared samples. The observed increase in the exchange bias field for laser irradiated samples has been attributed to the increased grain size and the improved (111) texture of the NiMn layer after laser irradiation.
Phase behavior of a fluid confined in slitlike pores with walls modified by preadsorbed chain molecules
Authors: Pizio O. , Borówko M. , Rżysko W. , Staszewski T. , Sokołowski S.
Published: January 2008

We have studied the microscopic structure, thermodynamics of adsorption, and phase behavior of Lennard-Jones fluid in slitlike pores with walls modified due to preadsorption of chain molecules. The chain species are grafted at the walls by terminating segments. Our theoretical considerations are based on a density functional approach in the semigrand canonical ensemble. The applied constraint refers to the constant number of grafted chain molecules in the pore without restriction of the number of chains at each of the walls. We have observed capillary condensation of Lennard-Jones fluid combined with the change of the distribution of chains from nonsymmetric to symmetric with respect to the pore walls. The phase diagrams of the model are analyzed in detail, dependent on the pore width, length of chains, and grafted density.
Microstructure and magnetic variations induced by plastic deformation in Ni72Cr16Fe8
Authors: Yao Yeong Der , Wang Shing Hoa , Chan Feng Shiu , Chen Chih Yuan
Published: January 2008

The microstructure and magnetic property of a cold rolled Ni72Cr16Fe8 alloy have been studied as a function of its plastic deformation from 0 to 75%. The saturation magnetization decreases as the strain increases. The Curie temperature is also decreased from 183to178K for samples with the deformed strain from 0 to 75%. The decrease of the magnetic properties could be related to the effects of the variation of its microstructure and the deformation induced crystal defects, such as vacancies and dislocations. The acicular (needlelike) twins, which is associated with the nonlinear λ-type electrical resistivity, were found in the specimen of 75% deformed strain.
Neutron scattering studies of spin-1∕2 twofold-period (alternating) and threefold-period quantum antiferromagnetic chains
Authors: Hase Masashi , Ozawa Kiyoshi , Kitazawa Hideaki , Tsujii Naohito , Dönni Andreas , Kohno Masanori , Hu Xiao , Matsuda Masaaki , Kakurai Kazuhisa , Kuroe Haruhiko
Published: January 2008

We studied magnetism of two cuprates using inelastic neutron scattering and magnetization measurements on powder samples. A spin gap of 6.2meV (72K) was observed in β-AgCuPO4. The spin system was determined as a spin-1∕2 twofold-period (alternating) antiferromagnetic (AF) chain with two exchange interaction values of 80 and 14K. Contrary to common knowledge, the strongest exchange interaction exists in a Cu–Cu bond with the distance of 5.20Å in spite of the existence of short Cu–Cu bonds. Cu3(P2O6OD)2 is known to have a spin-1∕2 threefold-period chain with J1-J2-J2 interactions, where J1 and J2 denote two AF exchange interaction parameters, showing a 1∕3 magnetization plateau. A spin gap of 9.8meV (114K) was found, which generated the magnetization plateau. The gap corresponds to a singlet-triplet-like excitation of an AF dimer formed by the dominant J1 interaction. We determined that J1=111K and J2=30K.