bluuebunny/crossref_metadata_2025 huggingface dataset:
Antimaterie – Spiegelbild oder Zerrbild. Antiwasserstoff im Labor
Authors: Kellerbauer Alban
Published: June 2007

Obwohl im Urknall gleiche Mengen von Antimaterie und Materie entstanden sind, überwiegt letztere heute im beobachtbaren Universum. Die Ursache für diese Asymmetrie gehört zu den ungelösten Rätseln der Physik. Der Grund könnte darin liegen, dass Antimaterie kein absolut perfektes Spiegelbild der Materie ist. Um Antimaterie daraufhin zu untersuchen, muss sie im Labor zur Verfügung stehen. Die Erzeugung von Antiwasserstoff‐Atomen im Labor gelingt seit 1995 erfolgreich am CERN. Doch bislang waren sie zu heiß, um sie zwischenspeichern und mit ihnen weiter experimentieren zu können. Dieses Ziel verfolgen derzeit mehrere Gruppen am CERN.
Präzisionsmessung der Feinstrukturkonstante
Authors: Müller Holger , Chiow Sheng‐wey , Long Quan , Herrmann Sven , Chu Steven
Published: June 2007

Interferometrie mit Materiewellen hat sich in jüngerer Vergangenheit zu einem Werkzeug für Präzisionsmessungen unterschiedlicher Art entwickelt. Unsere Gruppe an der Stanford University arbeitet an einer Messung der Feinstrukturkonstante α. Wir nutzen dabei den Rückstoß, den ein Cäsiumatom erfährt, wenn es mit vielen Photonen gleichzeitig wechselwirkt. Durch diese Multiphotonenprozesse lässt sich das Signal um einen Faktor hundert gegenüber früheren Experimenten erhöhen.
Physik und Philosophie im Schatten der Atombombe
Authors: Schaaf Michael
Published: June 2007

Am 28. April starb der Physiker, Philosoph und Friedensforscher Carl Friedrich von Weizsäcker im Alter von 94 Jahren in Starnberg. Wir würdigen den wohl letzten deutschen Universalgelehrten mit einem kurzen Nachruf sowie mit zwei Auszügen aus einem längeren Interview, das der Physikhistoriker Michael Schaaf 1996 mit von Weizsäcker geführt hat. Im ersten Teil geht es um von Weizsäckers Forschungen am Kohlenstoffzyklus im Innern von Sternen sowie um die Entdeckung der Kernspaltung. Im zweiten Teil, das im nächsten Heft folgt, äußert sich von Weizsäcker zu der Arbeit der deutschen Physiker während der Zeit des Nationalsozialismus an einer “Uranmaschine.”
Peeling of polydimethylsiloxane adhesives: The case of adhesive failure
Authors: Verdier Claude , Ravilly Guillaume
Published: June 2007

The adhesion properties of high molecular weight polydimethylsiloxane adhesives are measured using 90°‐peel adhesion tests, in the high velocity range. Such adhesives undergo mainly adhesive failure in this regime. The influence of viscosity (non‐Newtonian), adhesive thickness, peeling velocity, and backing properties are studied, and new unexpected behaviors are shown. The role of rheology and peeling velocity can be explained by an extension of a model already presented for cohesive failure, by using a power‐law fluid for the adhesive. On the other hand, the influence of the backing rigidity reveals to be coupled with the adhesive elastic properties, this effect being correlated to the introduction of a new parameter in the model, the Weissenberg number for viscoelasticity. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2113–2122, 2007
Early life events in asthma—diet
Authors: Devereux Graham
Published: June 2007

It has been hypothesized that the recent increase in the prevalence of asthma may, in part, be a consequence of changing diet. There is now increasing interest in the possibility that childhood asthma may be influenced by maternal diet during pregnancy and/or diet during early childhood. A number of observational studies and a childhood fish oil supplementation study provide little support for the notion that early childhood intake of polyunsaturated fatty acids (PUFAs) influence the development of childhood asthma. Recent work however, suggests that supplementation of maternal diet with fish oil is associated with altered neonatal immune responses to allergens. Further work is required to establish whether this immunological observation is translated into clinical outcomes. Two birth cohorts have now reported reduced maternal intake of vitamin E, zinc and vitamin D during pregnancy to be associated with increased asthma and wheezing outcomes in children up to the age of 5 years. Early life diet could modulate the likelihood of childhood asthma by affecting fetal airway development and/or influencing the initial early life interactions between allergens and the immune system. In animal models, vitamin E, zinc and vitamin D have been shown to modify fetal lung development and vitamin E, zinc, vitamin D and PUFA can modulate T‐cell responses. Further research, particularly, early life intervention studies need to be carried out to establish whether early life dietary intervention can be used as a public health measure to reduce the prevalence of childhood asthma. Pediatr Pulmonol. 2007; 42:663–673. © 2007 Wiley‐Liss, Inc.
Factors that correlate with sleep oxygenation in children with cystic fibrosis
Authors: Uyan Z.S. , Özdemir N. , Ersu R. , Akpınar İ. , Keskin S. , Çakır E. , Karadağ B. , Karakoç F. , Dağlı E.
Published: June 2007

Objective

Cystic fibrosis (CF) patients may develop hypoxemia during sleep. Limited information is available on nocturnal oxygen saturation in CF children with less severe lung disease. The aim of this study was to investigate the degree of nocturnal oxygen desaturation and factors that correlate with nocturnal oxygenation in CF children with normal pulmonary function tests (PFTs) or mild to moderate lung disease.

Method

Awake resting and post‐exercise SpO2 were measured by pulse oximetry. Each patient had overnight oximetry monitorization at home. Six minutes walk test (6MWT), Shwachman–Kulczycki (S–K), Brasfield and computed tomography (CT) scores, blood gas analysis and nutritional status of patients were evaluated.

Results

Twenty‐four patients with a median age of 9.5 years were included. Nocturnal mean SpO2 did not differ according to the severity of lung disease based on PFT. However, lowest SpO2 obtained was lower in children with both mild and moderate lung disease compared to normals (87.4% vs. 91.7%, respectively, p = 0.009). 95.8% of CF children with normal PFT or mild to moderate lung disease had desaturation events during sleep. Nocturnal mean SpO2 correlated with S–K (Spearman's rho = 0.64, p < 0.0001), Brasfield (Spearman's rho = 0.31, p = 0.007) and CT scores (Spearman's rho = −0.67, p < 0.0001) as well as PaO2 (Spearman's rho = 0.28, p = 0.021), SaO2 (Spearman's rho=0.28, p = 0.023), z‐score of weight (Spearman's rho = 0.23, p = 0.20) and height (Spearman's rho = 0.20, p = 0.30), there was no correlation with 6MWT.

Conclusions

In CF children with normal PFT or mild‐to‐moderate lung disease, nocturnal oxygenation may correlate with S–K, Brasfield and CT scores as well as PaO2, SaO2, z‐score of weight and height. Pediatr Pulmonol. 2007; 42:716–722. © 2007 Wiley‐Liss, Inc.
On the consistency between positron annihilation lifetime and Doppler broadening results in polypropylene
Authors: Djourelov N. , Dauwe C. , Palacio C. A. , Laforest N. , Bas C.
Published: June 2007

Polypropylene samples were measured as a function of the source exposure time at 20 K and as a function of the temperature (20‐400 K) simultaneously by Positron Annihilation Lifetime (PAL) and Doppler Broadening (DB) spectroscopy. The peak shape parameter (S) measured by DB can be calculated as a sum of contributions of specific parameters corresponding to each positron state. The contributions are obtained by analysis of the PAL spectra. The confinement of positronium (Ps) in a free volume hole (FVH) determines the self annihilation shape parameter Ssa of the para‐Ps, the pick‐off annihilation lifetime τpo, and supposes FVH size‐dependence of the pick‐off shape parameter Spo. The ortho‐Ps lifetime and shape parameters are used to compute Ssa. In this way, the temperature and time dependences of the S parameter are modelled. The fit of this model to the experimental S parameter shows a stronger dependence of the Spo on the FVH size (R) than the one as expected by taking into account only the Ps momentum. This result suggests that the penetration of Ps into the walls of the FVH must be properly considered and that the penetration depth depends on R itself. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Role of vacancies during creep and secondary precipitation in an underaged Al‐Cu‐Mg‐Ag alloy
Authors: Somoza A. , Macchi C. E. , Lumley R. N. , Polmear I. J. , Dupasquier A. , Ferragut R.
Published: June 2007

Aluminium alloys that are deliberately underaged show both enhanced creep resistance at elevated temperatures and high responses to secondary ageing at lower temperatures (e.g. 20‐65 °C). These phenomena appear to be strongly influenced by the presence of vacant lattice sites and positron annihilation spectroscopy has been used to study the roles of solute/vacancy interaction during precipitation in an aged Al‐Cu‐Mg‐Ag alloy. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Experimental studies of beta positron implantation profiles in condensed matter
Authors: Dryzek J.
Published: June 2007

The results of the new measurements of the linear absorption coefficient for positrons emitted from 22Na and 68Ge\68Ga sources are presented. As a result, improvements were made to the well‐known Gleason et al. (G. I. Gleason et al., Nucleonics 8, 12 (1951) [1]) formula giving the value of the mass absorption coefficient. It was shown that this coefficient depended not only on the maximum energy of emitted positrons but also on the atomic number the implanted absorber and exhibited an oscillatory dependence on atomic number for heavy absorbers. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Positron annihilation spectroscopy as a tool to develop self healing in aluminium alloys
Authors: Hautakangas S. , Schut H. , van der Zwaag S. , Rivera Diaz del Castillo P. E. J. , van Dijk N. H.
Published: June 2007

Positron lifetime and Doppler broadening spectroscopy have been applied to probe the free volume generation (vacancies, dislocations and nano‐cracks) during plastic deformation of a commercial aluminium AA2024 (T3) alloy. Aim of the total program is to study how solute atoms can be driven to the areas where initial cracking may occur in order to prevent the failure of the specimen. The phenomenon of closing the nano‐crack is called Self Healing, and can provide extra strength and ductility to the alloy under some loading conditions. Plastic deformation of over‐aged aluminum alloy at room temperature increases the average positron lifetime from initial value of 190 ps to 203 ps. The low momentum parameter S increases in agreement with the increase of open volume defects. The elastic deformation of the sample does not have a recordable effect on the positron annihilation data. It is also shown that the induced damage does not recover after loading the sample, i.e. the AA2024 in the T3 state is non self healing material, as expected, providing important first state result in the research of self healing Al alloys. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Simulated positron lifetime (SimPL): a Monte Carlo simulator for positron diffusion, trapping, and lifetime spectra
Authors: Lawther Derek W. , Gaudin André , Stewart Allan
Published: June 2007

A JAVA‐based Monte Carlo simulation program (SimPL) has been created which generates realistic positron lifetime (PL) spectra. The program achieves this by simulating the diffusion, trapping, and annihilation, of positrons in solids. Users can define: defect structures (type, size, concentration, and spatial distribution); behaviour of the positrons in each trap state (trapping rate, lifetime, and effective range of interaction); and spectrometer performance (time resolution, background). SimPL is shown to be very useful for assessing the accuracy of fitted parameter (lifetimes, intensities) values extracted from PL spectra using, e.g. PATFIT. It is also shown to be useful for quantifying the effect that defect spatial distributions have on the positron trapping fraction. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Design of a liquidless superconducting accelerator for positron annihilation lifetime spectroscopy
Authors: Oshima N. , Kuroda R. , He C. , Kinomura A. , Ohdaira T. , Toyokawa H. , Suzuki R. , Hayashizaki N. , Hattori T.
Published: June 2007

A design of a superconducting accelerator for a pulsed positron beam of ∼1 MeV for positron annihilation lifetime spectroscopy is proposed. The total system can be extremely small with an application of superconducting technology. Both a miniaturization and easy maintenance of the accelerator can be achieved by usage of a small liquidless refrigerator for cooling of a superconducting RF cavity. Moreover, the operation duty cycle of the superconducting cavity is ∼100% which is much larger than that of a normal conducting one. The required RF power to drive the system is ∼10 W, therefore a large‐size klystron is not necessary. The designed system including a slow positron source is small (∼2 m3) enough to be used in a general laboratory. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Vacancy‐solute association in coherent nanostructures formed in a commercial Al‐Zn‐Mg‐Cu alloy
Authors: Dupasquier A. , Ferragut R. , Iglesias M. M. , Quasso F.
Published: June 2007

The role of vacancy‐solute association in the formation of coherent precipitates at room temperature (RT) and at 70 °C was studied by means of coincidence Doppler broadening (CDB) spectroscopy. The formation of clusters and GP zones was monitored by differential scanning calorimetry (DSC). Two conditions were explored at low temperature: a) one‐step aging after solution treatment and quenching and b) secondary aging (after solution treatment and quenching + 5 days at RT + 8 min at 150°C). The assessment of the average fractional concentration of solute in contact with the vacancies was obtained by analyzing the CDB data. The results show considerable aggregation of Cu to vacancies at the very early stage of decomposition of the supersaturated solid solution; the contribution of Zn and Mg increases progressively with the formation of coherent precipitates. The preliminary exposure at 150 °C does not alter this sequence, although a reduction in the dissolution enthalpy observed during DSC scans shows retarded formation of coherent precipitates. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Identification of lattice defects in Cu thin films by positron annihilation spectroscopy
Authors: Mizuno Masataka , Kihara Teruo , Araki Hideki , Shirai Yasuharu , Onishi Takashi
Published: June 2007

Positron lifetime measurements have been performed for Cu thin films in order to identify lattice defects. Theoretical positron lifetimes of vacancy clusters of Cu are also calculated for identification of the experimental values. Cu thin films were prepared by electro chemical deposition (ECD) and physical vapour deposition (PVD). All of the Cu thin films have longer positron lifetimes than bulk Cu does. This indicates that lattice defects are introduced during deposition. However composition analysis of positron lifetimes shows that whereas vacancy clusters exist in the ECD‐Cu thin film, the positron lifetime of defect component in the PVD‐Cu thin films is shorter than that of mono‐vacancy. On the other hand, the positron lifetime of mono‐vacancy was detected in PVD‐Cu‐0.5 at%Sb thin film prepared by PVD. In order to elucidate the effect of Sb, first‐principles calculations have been performed for Cu including Sb and mono‐vacancy. The result suggests that mono‐vacancies are introduced because of the binding energy between a Sb atom and mono‐vacancy. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Microstructure investigations of ultra‐fine grained Mg‐Gd alloys prepared by high pressure torsion
Authors: Čížek J. , Procházka I. , Smola B. , Stulíková I. , Kužel R. , Matěj Z. , Cherkaska V. , Islamgaliev R. K. , Kulyasova O.
Published: June 2007

Mg‐Gd represents a promising light hardenable alloy with a high creep resistance even at elevated temperatures. A disadvantage of this alloy consists in a low ductility. Recently it has been demonstrated that ultra fine grained (UFG) metals with grain size around 100 nm can be produced by high pressure torsion (HPT). A number of UFG metals exhibit favourable mechanical properties consisting in a combination of a very high strength and a significant ductility. The HPT processing creates a high density of defects, especially dislocations, in UFG material. These defects play key role in the specific physical properties of UFG materials. Defects studies of UFG materials are, therefore, very important for understanding of their unusual properties. Positron lifetime (PL) spectroscopy is one of the most powerful techniques for investigations of open‐volume defects. In the present work we employed PL spectroscopy for defect studies of UFG Mg‐Gd alloys prepared by HPT. The PL investigations were combined with transmission electron microscopy, X‐ray diffraction, and microhardness measurements. At first, the microstructure of the as‐deformed specimens was characterized. Subsequently, the specimens were isochronally annealed and the development of microstructure with increasing temperature was investigated. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High‐resolution reconstruction of a tracer dispersion event: application to ETEX
Authors: Bocquet Marc
Published: June 2007

In a previous two‐part paper, new methods for reconstructing the source of an atmospheric tracer at regional scale were developed. Specifically, the ‘maximum entropy on the mean’ (MEM) method was extended to large (though linear) data assimilation problems. Tests using twin experiments and a limited subset of the data from the European Tracer Experiment (ETEX) were performed. Although temporal reconstruction knowing the location of the source was satisfying, a full three‐dimensional reconstruction with real data was still out of reach.

In this paper, using the MEM method and some of its refinements, a reconstruction using all ETEX‐I measurements at a resolution of 1.125 × 1.125 × 1 h is shown to be possible. This allows for a reconstruction of the full dispersion event. The MEM retrieval of the tracer plume using what is believed to be a good prior is then compared to retrievals using other priors, including Gaussian priors. Eventually, a reconstruction using all data sequentially in time (rather than all together) is obtained. This helps define what a maximum‐entropy filter applied to sequential data assimilation of a linear tracer should be able to do, with a view to an efficient emergency response in case of an accidental release of pollutant. Copyright © 2007 Royal Meteorological Society
Gap flows: Results from the Mesoscale Alpine Programme
Authors: Mayr Georg J. , Armi Laurence , Gohm Alexander , Zängl Günther , Durran Dale R. , Flamant Cyrille , Gaberšek Saša , Mobbs Stephen , Ross Andrew , Weissmann Martin
Published: June 2007

An overview of advances in the observation, modelling, forecasting, and understanding of flows through gaps achieved in the Mesoscale Alpine Programme is given. Gaps are lateral constrictions of topography (level gaps) often combined with vertical terrain changes (passes). Of the possible flow configurations, only an asymmetric one (relatively deep and slow upstream, accelerating and thinning downstream), which connects two different ‘reservoirs’ on each side of the gap, is examined. The flow is strongly nonlinear, making hydraulics (reduced‐gravity shallow‐water theory) rather than linear theory the simplest conceptual model to describe gap flow. Results from idealized topographical and flow conditions are presented, together with gap flows through a pass in the central Alpine Wipp Valley. For a given depth of the upstream reservoir, the gap controls the mass flux through it and marks the transition from a subcritical flow state upstream to a supercritical one downstream, which eventually adjusts to the downstream ‘reservoir’ in a hydraulic jump. Three gap flow prototypes were found: a classical layer one with neutral stratification and a capping inversion and two with a continuous stratification, for which a special analytical self‐similar hydraulic solution exists. In all three cases, a deepening wedge of nearly mixed and stagnant air forms on top of the gap flow plunging down from the pass. The descent causes a warming and (relative) drying of the air, making gap flows a special case of föhn. Topographical variations smaller than the gap scale cause additional hydraulic jumps, flow separation, vorticity banners, gravity waves, and interactions with cold pools. Turbulent friction cannot be neglected. The climatological frequency of gap flows depends on the establishment of two different reservoirs and reaches 20% for the Wipp Valley. Copyright © 2007 Royal Meteorological Society
Lessons on orographic precipitation from the Mesoscale Alpine Programme
Authors: Rotunno Richard , Houze Robert A.
Published: June 2007

Although moisture‐laden airflow towards a mountain is a necessary ingredient, the results from the Mesoscale Alpine Programme (MAP) demonstrate that detailed knowledge of the orographically modified flow is crucial for predicting the intensity, location and duration of orographic precipitation. Understanding the orographically modified flow as it occurs in the Alps is difficult since it depends on the static stability of the flow at low levels, which is heavily influenced by synoptic conditions, the complex effects of latent heating, and the mountain shape, which has important and complicated variations on scales ranging from a few to hundreds of kilometres. Central themes in all of the precipitation‐related MAP studies are the ways in which the complex Alpine orography influences the moist, stratified airflow to produce the observed precipitation patterns, by determining the location and rate of upward air motion and triggering fine‐scale motions and microphysical processes that locally enhance the growth and fallout of precipitation. In this paper we review the major findings from the MAP observations and describe some new research directions that have been stimulated by MAP results. Copyright © 2007 Royal Meteorological Society
Upper‐tropospheric flow features and the Alps: An overview
Authors: Hoinka Klaus P. , Davies Huw C.
Published: June 2007

One focus of the Mesoscale Alpine Programme (MAP) was the study of upper‐tropospheric potential vorticity (PV) anomalies that take the form of narrow meridionally elongated troughs termed ‘PV streamers’. A systematic effort was undertaken within the MAP framework to: establish a streamer climatology, develop appropriate instrumentation and undertake a measurement programme to better ascertain their structure, study both their intrinsic dynamics and their modification by the Alps, and perform model experiments to examine their significance for numerical weather prediction.

Here an overview is given of the progress made toward achieving these objectives. In particular it is shown that PV streamers translating toward the Alpine region are dynamically distinctive and constitute an identifiable precursor of and contribute seminally to heavy precipitation events on the south side of the Alps and possess rich mesoscale sub‐structures that can be examined with novel water vapour absorption lidar instrumentation. It is also shown that the accurate representation of a streamer might well be a critical prerequisite for accurate quantitative prediction of mesoscale precipitation. Copyright © 2007 Royal Meteorological Society
Turbulent flows on forested hilly terrain: the recirculation region
Authors: Poggi D. , Katul G. G.
Published: June 2007

A number of analytical and numerical studies employing first‐order closure principles have suggested that canopy flows on gentle sinusoidal hills feature a recirculation region, situated on the lee side, that can dramatically affect scalar transfer between the biosphere and the atmosphere. To date, the onset of this region, and its effects on bulk flow properties, have not been experimentally investigated. We study the applicability of first‐order closure schemes jointly with the properties of this recirculation region, using detailed laser Doppler anemometry (LDA) measurements. These experiments are conducted in a neutrally stratified boundary‐layer flow within a large flume over a train of gentle and narrow hills. The canopy is composed of an array of vertical cylinders with a frontal‐area index concentrated in the upper third, to resemble a tall hardwood forest at maximum leaf area. The LDA measurements are recorded for both sparse and dense canopies. We find that, while the onset of a recirculation region is ambiguous in the sparse‐canopy case, it is well delineated in the dense‐canopy case. This finding constitutes the first experimental evidence confirming the analytical and numerical model predictions concerning this region in dense canopies on gentle hills. Moreover, we show that the presence of the recirculation region can explain the anomalous pressure variation across the hill (first reported in numerical simulations) using an ‘effective hill shape’ function. Detailed momentum‐flux measurements show, surprisingly, that the effective mixing length leff within the canopy and in the inner layer is not significantly affected by the recirculation region. We expected leff to be comparable to the size of the vortex responsible for the recirculation zone, but the measurements show that leff maintains its canonical canopy turbulence shape. Using laser‐induced fluorescence (LIF) measurements, we find that the recirculation region is not characterized by a classical ‘rotor’, but by a highly intermittent zone with alternating positive and negative velocity values in the lower layers of the canopy. These LIF measurements may explain why leff maintains its canonical canopy turbulence shape in the recirculation region. The LIF measurements also show that the main mechanism for scalar transfer within the recirculation region is a sequence of accumulation–ejection episodes that are quasi‐periodic in nature. Copyright © 2007 Royal Meteorological Society
Restricted randomization and multiple responses in industrial experiments
Authors: Bjerke Frøydis , Langsrud Øyvind , Aastveit Are Halvor
Published: June 2007

Two issues regarding designed experiments are discussed; restrictions on randomization and multiple responses. The former is typically related to hard‐to‐vary factors and factors appearing in separate stages of a process experiment. Randomization restrictions should be taken into account in the construction of the design as well as in the statistical modelling. In the paper, a case study of sausage production is discussed, having a split‐plot model with correlated multiple responses. Multiple responses are handled in two ways, by principal component analysis (PCA) followed by ANOVA of the principal components, and by a newly developed alternative, the ‘50–50 MANOVA’. Multiple tests of correlated response variables are also described. Practical aspects of the planning, performing, response measurements, and statistical analysis are emphasized throughout. Hence, the paper aims to extend the utility of statistical methods in industry by linking design of experiments to multivariate analysis of the responses. Copyright © 2007 John Wiley & Sons, Ltd.
Simultaneous analysis of multiple bioactive constituents in Rheum tanguticum Maxim. ex Balf. by high‐performance liquid chromatography coupled to tandem mass spectrometry
Authors: Jin Wei , Wang Ying‐Feng , Ge Ri‐Li , Shi Hai‐Ming , Jia Cun‐Qin , Tu Peng‐Fei
Published: June 2007

A simple, rapid method was developed using on‐line high‐performance liquid chromatography (HPLC)–diode array detection (DAD)/electrospray ionization mass spectrometry (ESI‐MS) to simultaneously analyze multiple bioactive constituents in the extract of Rheum tanguticum Maxim. ex Balf. (Dahuang), a traditional Chinese medicine (TCM). Many bioactive constituents gave prominent [MH]− ions in the negative ion ESI mass spectra. Among them, 41 different constituents including 16 anthraquinone derivatives, 7 phenylbutanone glucopyranosides, 4 stilbenes and 14 tannins were unambiguously identified or tentatively characterized based on their retention times, UV spectra and mass spectra in comparison with the data from standards or references. Meanwhile, some principles of fragmentation behavior for different types of constituents were proposed, which could contribute to the elucidation of these constituents in Rheum tanguticum. Copyright © 2007 John Wiley & Sons, Ltd.
Membrane proteome in Escherichia coli probed by MS3 mass spectrometry: a preliminary report
Authors: Cirulli Claudia , Marino Gennaro , Amoresano Angela
Published: June 2007

Characterization of the membrane proteome is particularly intriguing since a better knowledge in this field might lead to new insights into the function of different membrane systems. Despite the biological relevance of surface proteins however, their characterization still remains a challenging task. Outer membrane proteins (OMPs) of Gram‐negative bacteria are key molecules that interface the cell with the environment. Hence, surface proteins of Gram‐negative bacteria contain proteins that might be good targets for drugs, antimicrobials or detection systems and they may become components of effective vaccines. In this respect, Escherichia coli has been chosen as a model organism for several structural and functional studies aimed at understanding the biophysical and biochemical organization of proteins in Gram‐negative cell walls. Here we present first results for the identification of bacterial surface exposed proteins in E. coli K12 based on the use of dansyl chloride labelling coupled with bidimensional tandem mass spectrometry exploiting the advantage of precursor ion/MS3 scan modes. This procedure resulted in a promising, simple, and rapid strategy for the identification of membrane proteins in E. coli as model organism, thus avoiding time‐consuming procedures based on two‐dimensional liquid chromatography and electrophoresis. The proteins identified could be grouped into five major families: outer membrane (29 proteins), lipoproteins (6 proteins), transmembrane (43 proteins) families. Copyright © 2007 John Wiley & Sons, Ltd.
Boundedness in Lurie system with stiffening nonlinearities
Authors: Ben Abdallah Abdallah , Hammami Mohamed Ali
Published: June 2007

In this paper, we deal with the problem of boundedness of solutions in single‐input single‐output Lurie system. We prove the boundedness of solutions from the stability of zero dynamics under a restriction on the nonlinearity. The linear block is supposed to be of relative degree one or two, stabilizable by high‐gain output feedback and not necessary minimum phase. The nonlinearity is required to have the stiffening property. Copyright © 2007 John Wiley & Sons, Ltd.
Cluster without fluster: The effect of correlated outcomes on inference in randomized clinical trials
Authors: Proschan Michael , Follmann Dean
Published: June 2007

Inference for randomized clinical trials is generally based on the assumption that outcomes are independently and identically distributed under the null hypothesis. In some trials, particularly in infectious disease, outcomes may be correlated. This may be known in advance (e.g. allowing randomization of family members) or completely unplanned (e.g. sexual sharing among randomized participants). There is particular concern when the form of the correlation is essentially unknowable, in which case we cannot take advantage of the correlation to construct a more efficient test. Instead, we can only investigate the impact of potential correlation on the independent‐samples test statistic. Randomization tends to balance out treatment and control assignments within clusters, so it is logical that performance of tests averaged over all possible randomization assignments would be essentially unaffected by arbitrary correlation. We confirm this intuition by showing that a permutation test controls the type 1 error rate in a certain average
sense whenever the clustering is independent of treatment assignment. It is nonetheless possible to obtain a ‘bad’ randomization such that members of a cluster tend to be assigned to the same treatment. Conditioned on such a bad randomization, the type 1 error rate is increased. Published in 2007 by John Wiley & Sons, Ltd.
Field tests of wind turbines submitted to real voltage dips under the new Spanish grid code requirements
Authors: Gómez E. , Fuentes J. A. , Molina‐García A. , Ruz F. , Jiménez F.
Published: June 2007

This paper adds the new Spanish grid code to the previously published works about the comparison of international regulations for connection of wind turbines to the network. All the electrical magnitudes—currents and active and reactive power—regulated in the Spanish grid code are studied when the wind turbines are submitted to real voltage dips. Because grid codes and, specifically, the Spanish grid code do not fix the reactive power definition to be applied, four definitions commonly used have also been studied. Taking advantage of the voltage dips field tests carried out to the Gamesa G80 wind turbines, the results obtained for two representative voltage dip tests are presented: a three‐phase and a phase‐to‐phase voltage dip. Copyright © 2007 John Wiley & Sons, Ltd.
Overexpression of the rFCA RNA Recognition Motif Affects Morphologies Modifications in Rice (Oryza sativa L.)
Authors: Hong Fang , Attia Kotb , Wei Chun , Li Kegui , He Guangming , Su Wei , Zhang Qinghua , Qian Xiaoyin , Yang Jinshui
Published: June 2007

RNA recognition motifs as important regulators of gene expression are highly conserved in animals and plants. The FCA floral promotion gene in Arabidopsis encodes a protein, containing two RNA recognition motifs (RRM) and a WW protein interaction domain. Here we isolated FCA cDNA from rice. FCA in rice (rFCA) was homologous to FCA-gamma of Arabidopsis and contained conserved domains. To investigate the function of RRM domain, fragment RRM1 and RRM2 of rFCA were introduced into rice subspecies Oryza sativa L. subsp. Indica var. 9311 and another rice subspecies Oryza sativa L. subsp. Japonica var. zhonghua11 transformation. Two transgenic lines exhibited similar phenotypes, flowering time delay, seed size and cell volume of transgenic plants was increased. These results showed that constitutive expression of RRMs could regulate cellular size. The patterns of overexpression of two RRM domains and their similar morphologies indicate they may play a same role.
Type 1 Diabetic Serum Interferes with Pancreatic β-cell Ca2+ -Handling
Authors: Dekki N. , Nilsson R. , Norgren S. , Rössner S. M. , Appelskog I. , Marcus C. , Simell O. , Pugliese A. , Alejandro R. , Ricordi C. , Berggren P. O. , Juntti-Berggren L.
Published: June 2007

The aim of this study was to clarify the frequency of patients with type 1 diabetes that have serum that increases pancreatic β-cell cytoplasmic free Ca2+ concentration, [Ca2+]i, and if such an effect is also present in serum from first-degree relatives. We also studied a possible link between the serum effect and ethnic background as well as presence of autoantibodies. Sera obtained from three different countries were investigated as follows: 82 Swedish Caucasians with newly diagnosed type 1 diabetes, 56 Americans with different duration of type 1 diabetes, 117 American first-degree relatives of type 1 diabetic patients with a mixed ethnic background and 31 Caucasian Finnish children with newly diagnosed type 1 diabetes. Changes in [Ca2+]i, upon depolarization, were measured in β-cells incubated overnight with sera from type 1 diabetic patients, first-degree relatives or healthy controls. Our data show that there is a group constituting approximately 30% of type 1 diabetic patients of different gender, age, ethnic background and duration of the disease, as well as first-degree relatives of type 1 diabetic patients, that have sera that interfere with pancreatic β-cell Ca2+-handling. This effect on β-cell [Ca2+]i could not be correlated to the presence of autoantibodies. In a defined subgroup of patients with type 1 diabetes and first-degree relatives a defect Ca2+-handling may aggravate development of β-cell destruction.
Estimating seasonal density of blue sheep (Pseudois nayaur) in the Helan Mountain region using distance sampling methods
Authors: Liu Zhensheng , Wang Xiaoming , Teng Liwei , Cui Duoying , Li Xinqing
Published: June 2007

The monitoring of animal populations is necessary to conserve and manage the rare or harvest species and to understand the population change over several years. We used distance sampling methods to estimate seasonal density of blue sheep in a 2,740 km2area of Helan Mountain region by walking along 32 transect lines from winter 2003 to autumn 2005. In all, 367–780 blue sheep were observed in 91–143 groups in the surveys during the seasons. Observed mean group size ranged from 3.42 to 8.35 individuals; encounter rate, the number of groups detected per kilometre, varied from 0.19 to 0.30 during the seasons. A hazard rate key function with cosine series expansion and a half‐normal key function with either cosine or simple polynomial series expansion were the best fitting models based on the lowest value of Akaike's information criterion (AIC). Density estimates varied between 3.627 sheep per square kilometre in spring 2004 and 4.635 per square kilometre in summer 2005. There were no detectable differences in estimated density among seasons (P= 0.887). The estimated density of blue sheep was negatively correlated with the total number of deaths (P< 0.05), number of sub‐adult males’ deaths (P< 0.05), number of sub‐adult females’ deaths (P< 0.05), and number of male lambs’ deaths (P< 0.05). We concluded that distance sampling surveys should be used to monitor long‐term population trends to provide the best quantitative estimates of blue sheep populations in the Helan Mountains region.
Bcl‐2 small hairpin RNAs enhance radiation‐induced apoptosis in A549 cells
Authors: He Dong‐Mei , Zhang Yuan , Liu Ge‐Xiu
Published: June 2007

Bcl‐2, a prominent member of the family of proteins, is responsible for dys‐regulation of apoptosis and resistance to chemotherapy and radiotherapy. This study investigated whether small hairpin RNA (shRNA) targeting Bcl‐2 could render A549 cells more susceptible to gamma radiation‐induced apoptosis. Recombinant Bcl‐2 shRNAs expression vector were transfected into A549 cells with Lipofectamine 2000. Transfected cells were screened in 800 mg/ml G418 screening medium, and after stable transfection, silencing was examined. Expression of the Bcl‐2 protein was assayed using Western blot in A549 cells. Inhibition of cell growth was assessed by a MTT assay. Apoptosis was determined by morphological observation and flow cytomertry. Expression levels of Bcl‐2 protein from A549 cells decreased after stable transfection with Bcl‐2 shRNAs. No differences in Bcl‐2 protein levels between control shRNA group and untreated cells were noted. After stable transfection with Bcl‐2 shRNAs the viability of cells was less than after stable transfection with those with control shRNAs and untransfected A549, respectively (P < 0.05). Control shRNA had no significant effect on growth of cells. Radiation significantly inhibited the growth of cells stably transfected with Bcl‐2 shRNA (P < 0.05). No difference in survival between the cells with control shRNA and untransfected cells was noted. Using Giemsa staining, cells stably transfected with Bcl‐2 shRNA combined with radiation at 48 h displayed changes of apoptosis. After treatment with radiation apoptotic rates of the A549 cells stably transfected with Bcl‐2 shRNA significantly increased (P < 0.05), compared with the cells with control shRNA and untransfected cells. shRNAs against the Bcl‐2 mRNA increases radiation‐induced apoptosis in A549 cells.
Antepartum percutaneous renal biopsy
Authors: Wide‐Swensson D. , Strevens H. , Willner J.
Published: June 2007

Objective: To assess the value and adverse effects of an ultrasound‐guided renal biopsy technique in women with normal and pathologic pregnancies. Method: Biopsy samples were taken from 36 women with hypertensive disease (28 with pre‐eclampsia) and 18 healthy pregnant women using a thin needle and an ultrasound‐guided biopsy device. Results: Glomerular endotheliosis, a structural change typical of pre‐eclampsia, was found in all hypertensive women, but it was more pronounced in the 28 pre‐eclamptic women than in the 8 women with nonproteinuric hypertension. A similar change, however, was seen in 11 of the 18 controls. One serious adverse event occurred, retroperitoneal hematoma, in the woman with the most severe pre‐eclampsia. Conclusion: Glomerular endotheliosis is not to be considered pathognomonic for pre‐eclampsia. Few complications followed renal biopsy in this study, but complications arose in the sickest patient. It is probably not advisable to perform antepartum renal biopsies in pregnant women with a rapidly deteriorating renal function and swollen kidneys. In these women, the biopsy does not facilitate diagnosis and is hazardous.
Gene Expression Analysis in Sinonasal Polyposis before and after Oral Corticosteroids: A Preliminary Investigation
Authors: Bolger William E. , Joshi Arjun S. , Spear Samuel , Nelson Michael , Govindaraj Krishnamurthy
Published: June 2007

OBJECTIVE

To characterize gene expression in sinonasal polyps and to gain insight into change in expression after oral corticosteroid treatment.

STUDY DESIGN AND METHODS

Nasal polyps were obtained before and after oral corticosteroid treatment and gene expression was analyzed with a focused gene array technique.

RESULTS

Pretreated sinonasal polyps demonstrated high gene expression for chemokine and leukotriene receptor genes (CCR2, CCR5, CX3CL1, and LTB4R) in all patients. After treatment, the global effects of corticosteroids were evident on gene expression.

CONCLUSIONS

Gene array techniques hold promise as a research method in sinonasal polyposis. The potential benefits, as well as the potential challenges, in using these research methods will be discussed.
The Role of FDG‐PET/CT Imaging in Head and Neck Malignant Conditions: Impact on Diagnostic Accuracy and Patient Care
Authors: Gordin Arie , Golz Avishay , Keidar Zohar , Daitzchman Marcello , Bar‐Shalom Rachel , Israel Ora
Published: June 2007

BACKGROUND

To assess the value of positron emission tomography/computed tomography (PET/CT) with 18F‐Fluorodeoxyglucose (FDG) in patients with head and neck carcinoma as compared with PET and conventional imaging alone, and to assess the impact of PET/CT on further clinical management.

STUDY DESIGN

Prospective nonrandomized study.

SETTING

Ninety patients with head and neck tumors had 107 PET/CT examinations.

RESULTS

The study analysis showed that PET/CT had a sensitivity of 89%, specificity 95%, PPV 94%, NPV 90%, and accuracy of 92%. PET/CT altered management in 51 patients (56%). PET/CT eliminated the need for previously planned diagnostic procedures in 24 patients, induced a change in the planned therapeutic approach in 21 patients and guided biopsy in 6 patients.

CONCLUSIONS

PET/CT is an imaging modality with high diagnostic performance in the assessment of head and neck cancer, and induced a change in further clinical management in more than half of the study population.
Detection of Gastric Pepsin in Middle Ear Fluid of Children with Otitis Media
Authors: He Zhaoping , O'Reilly Robert C. , Bolling Laura , Soundar Sam , Shah Mansi , Cook Steven , Schmidt Richard J. , Bloedon Esa , Mehta Devendra I.
Published: June 2007

OBJECTIVE

We sought to confirm the finding of pepsin/pepsinogen in the middle ear fluid of children with otitis media in a larger sample size using a sensitive and specific pepsin assay.

STUDY DESIGN AND SETTING

We evaluated 152 children (225 ear samples) in a prospective study at a tertiary care children's hospital. The presence of pepsin in middle ear aspirates was determined using enzymatic assay.

RESULTS

Of the patients, 14.4 percent (22 of 152) had detectable pepsin activity in one or both of the ear samples with no pepsin activity detected in control serum. Average pepsin concentration in the samples was 96.6 ± 170.8 ng/ml, ranging from 13 to 687 ng/ml. Pepsin concentration in the middle ear of children younger than 1.0 year was significantly higher than in older age groups.

CONCLUSION AND SIGNIFICANCE

Results indicate that pepsin/pepsinogen is present in the middle ears of children with otitis media, although not at the high rate previously reported. Gastric reflux may be one causative factor in the pathogenesis of otitis media.
Safety and Outcomes of Balloon Catheter Sinusotomy: A Multicenter 24‐Week Analysis in 115 Patients
Authors: Bolger William E. , Brown Christopher L. , Church Christopher A. , Goldberg Andrew N. , Karanfilov Boris , Kuhn Frederick A. , Levine Howard L. , Sillers Michael J. , Vaughan Winston C. , Weiss Raymond L.
Published: June 2007

OBJECTIVE

The aim of this study was to further evaluate the safety and effectiveness of balloon catheter devices to dilate obstructed sinus ostia/perform sinusotomy.

METHODS

Through a prospective, multicenter evaluation, safety was assessed by rate of adverse events, patency was determined by endoscopic examination, and sinus symptoms were determined by the Sino‐Nasal Outcome Test (SNOT 20).

RESULTS

At the conclusion of the 24‐week analysis, endoscopy determined that the sinusotomy was patent in 80.5% (247 of 307) sinuses and nonpatent in 1.6% (5 of 307), and could not determine ostial patency status in 17.9% (55 of 307). Of the ostia visualized on endoscopy, 98% were patent (247 of 252), while 2% (5 of 252) were considered nonpatent. SNOT 20 scores showed consistent symptomatic improvement over baseline. Revision treatment was required in 3 sinuses (3 of 307 sinuses, 0.98%) in 3 patients (3 of 109 patients, 2.75%).

CONCLUSION

Balloon catheter technology appears safe and effective in relieving ostial obstruction. Patients were pleased and indicated that they experienced symptomatic improvement.
Swallowing before and after Tonsillectomy as Evaluated by Surface Electromyography
Authors: Vaiman Michael , Krakovski Daniel , Gavriel Haim
Published: June 2007

OBJECTIVES

Surface electromyography (sEMG) was performed on adult patients (n = 40) following tonsillectomy to evaluate recovery by objective means.

METHODS

Evaluated parameters included timing of swallowing and continuous drinking, electric amplitude and graphic patterns of masseter (MS), and measurement of infrahyoid (INF) and submental (SUB) muscles after tonsillectomy and comparison with normative database.

RESULTS

The duration of drinking periods showed significant increase among patients; single‐swallow durations remained normal. The electric activity of MS and INF muscles was significantly higher among the patients compared with normative database. It took one month until all the EMG data returned to normal.

CONCLUSION

Tonsillectomy affects muscle activity during swallowing by involving additional muscles in deglutition. EMG is a simple reliable method for postoperative evaluation and might contribute to comparative analysis of different tonsillectomy techniques. EMG can be used during pre‐ and postoperative stages to monitor recovery and functional improvement of throat muscles and deglutition.

SIGNIFICANCE

The reported sEMG method and obtained data might be further used: 1) As an additional tool for comparison of different methods of tonsillectomy (eg, cold vs hot dissection, laser surgery, etc); 2) For further development of objective postsurgical pain assessment; 3) As an additional tool for assessment and development of less traumatic surgical technique; and 4) For monitoring of recovery in difficult cases