bluuebunny/crossref_metadata_2025 huggingface dataset:
Automatic phase correction of 2D NMR spectra by a whitening method
Authors: Balacco Giuseppe , Cobas Carlos
Published: February 2009

A new method for the automatic phase correction of multidimensional NMR spectra is described. It is based on the whitening concept formulated as the ‘maximization of the number of white pixels into a bitmap that corresponds to the spectrum’. This process of maximization can be factorized along the individual axes of the spectrum and this property makes the method robust and fast. It employs a statistic measure based on a large number of spectral data points and, for this reason, is very tolerant to low signal‐to‐noise ratio (SNR) and local artifacts. The algorithm can efficiently phase either homonuclear or heteronuclear experiments and, unlike other previous methods, it can also process automatically spectra containing positive or negative peaks so that it is not necessary to deal with individual or special cases Copyright © 2009 John Wiley & Sons, Ltd.
Compatible dual‐echo arteriovenography (CODEA) using an echo‐specific K‐space reordering scheme
Authors: Park Sung‐Hong , Moon Chan‐Hong , Bae Kyongtae Ty
Published: February 2009

An improved dual‐echo sequence magentic resonance (MR) imaging technique was developed to simultaneously acquire a time‐of‐flight MR angiogram (MRA) and a blood oxygenation level‐dependent MR venogram (MRV) in a single MR acquisition at 3 T. MRA and MRV require conflicting scan conditions (e.g., excitation RF profile, flip angle, and spatial presaturation pulse) for their optimal image quality. This conflict was not well counterbalanced or reconciled in previous methods reported for simultaneous acquisition of MRA and MRV. In our dual‐echo sequence method, an echo‐specific K‐space reordering scheme was used to uncouple the scan parameter requirements for MRA and MRV. The MRA and MRV vascular contrast was enhanced by maximally separating the K‐space center regions acquired for the MRA and MRV, and by adjusting and applying scan parameters compatible between the MRA and MRV. As a preliminary result, we were able to acquire a simultaneous dual‐echo MRA and MRV with image quality comparable to that of the conventional single‐echo MRA and MRV that were acquired separately at two different sessions. Furthermore, integrated with tilted optimized nonsaturating excitation and multiple overlapping thin‐slab acquisition techniques, our dual‐echo MRA and MRV provided seamless vascular continuity over a large coverage volume of the brain anatomy. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Prevalence of urinary incontinence and associated risk factors in nursing home residents: A systematic review
Authors: Offermans May P.W. , Du Moulin Monique F.M.T. , Hamers Jan P.H. , Dassen Theo , Halfens Ruud J.G.
Published: February 2009

Aims

To determine not only prevalence rates of urinary incontinence (UI) in nursing home residents but also factors influencing these prevalence rates, and to provide an overview of risk factors associated with UI in this group.

Methods

A systematic review was performed using multiple databases including MEDLINE, EMBASE, CINAHL, PsycINFO and the Cochrane Library from January 1997 to April 2008. In addition, the bibliographies of all relevant articles were searched. Two authors independently assessed the eligibility of all studies and extracted data on study design, population characteristics, definition of incontinence, measurement instrument, risk factors and prevalence rates.

Results

Twelve articles containing 16 studies met the eligibility criteria. Prevalence rates of UI in nursing home residents ranged from 43% to 77% (median 58%). When comparing studies, the influencing factors on UI prevalence of age and sex were identified. In total 45 risk factors were described. Within individual study populations, sex, age, cognitive function, dementia, bedfast and locomotion were associated with UI.

Conclusions

UI prevalence rates in nursing homes are high and the influencing factors poorly understood. Although important risk factors similar to those in the general population have been identified, risk factors related to the care process should be further investigated. Neurourol. Urodynam. 28:288–294, 2009. © 2009 Wiley‐Liss, Inc.
Patients with painful bladder syndrome have altered response to thermal stimuli and catastrophic reaction to painful experiences
Authors: Lowenstein Lior , Kenton Kimberly , Mueller Elizabeth R , Brubaker Linda , Heneghan Mary , Senka Judith , FitzGerald Mary Pat
Published: February 2009

Aims

To compare cutaneous sensory thresholds, habituation to somatic stimuli, and tendency towards catastrophic reaction to painful stimuli in patients with Painful Bladder Syndrome (PBS) to controls without PBS.

Method

Thermal and vibratory sensory thresholds were established in 11 PBS patients and 10 controls at C5, T1, T12, and S3 dermatomes. Supra‐threshold thermal stimuli were then applied at T12 and S3 for 60 sec while patients periodically rated the intensity of stimuli using a visual analog scale. A Pain Catastrophizing Scale (PCS) questionnaire was also completed by all participants before testing.

Results

PBS patients were less sensitive to warm stimuli in the T12 dermatome than asymptomatic controls (thresholds 36.6 ± 1.10°C vs. 35.3 ± 1.0°C, P < 0.02) but otherwise had similar thermal and vibratory thresholds. Habituation to supra‐threshold stimuli at T12 and S3 dermatomes was more common in controls than PBS subjects (7 (70%) vs. 2 (18%), P < 0.03 and 9 (90%) vs. 3 (27%), P < 0.008, respectively). The PCS score correlated with the duration of PBS symptoms and with thresholds to warm stimuli at T12 dermatome (ρ = 0.65, P < 0.03 and ρ = 0.5, P < 0.021, respectively).

Conclusion

Our data suggests that habituation to stimuli may be impaired and that a catastrophic reaction to perceived stimuli may be involved in the sensory experience of PBS patients and facilitate chronic pain. Neurourol. Urodyn. 28:400–404, 2009. © 2009 Wiley‐Liss, Inc.
Voiding dysfunction in patients with Parkinson's disease: Impact of neurological impairment and clinical parameters
Authors: Sammour Zein M. , Gomes Cristiano M. , Barbosa Egberto R. , Lopes Roberto I. , Sallem Flávio S. , Trigo‐Rocha Flavio E. , Bruschini Homero , Srougi Miguel
Published: February 2009

Aims

We assessed the lower urinary tract symptoms (LUTS) of patients with Parkinson's disease (PD) and their association with different clinical parameters.

Methods

We prospectively evaluated 110 patients (84 men), with a mean age of 61.8 ± 9.6 years. Mean duration of the disease was 12.3 ± 7.2 years. Neurological impairment was assessed by the Hoehn–Yahr and the Unified Parkinson Disease Rating scales. LUTS were assessed by the International Continence Society questionnaire. We evaluated the impact of age, PD duration, neurological impairment, gender, and use of anti‐Parkinsonian drugs on the voiding function.

Results

On multivariate analysis, voiding dysfunction increased with the neurological impairment, but not with patient's age or disease duration. Quality of life (QOL) was affected by the severity of LUTS, and the symptoms with the worst impact were frequency and nocturia. Sixty‐three (57.2%) patients were symptomatic. They did not differ with the asymptomatic as to age and disease duration, but had more severe neurological impairment. No impact on LUTS was associated with the use of levodopa, anticholinergics, and dopamine receptor agonists. Men and women were similarly affected by urinary symptoms.

Conclusions

The severity of the neurological disease is the only predictive factor for the occurrence of voiding dysfunction, which affects men and women alike. Neurourol. Urodyn. 28:510–515, 2009. © 2009 Wiley‐Liss, Inc.
Evidence for benefit of transversus abdominis training alone or in combination with pelvic floor muscle training to treat female urinary incontinence: A systematic review
Authors: Bø Kari , Mørkved Siv , Frawley Helena , Sherburn Margaret
Published: February 2009

Aims

Pelvic floor muscle training (PFMT) has Level A evidence to treat female urinary incontinence (UI). Recently, indirect training of the pelvic floor muscles (PFM) via the transversus abdominis muscle (TrA) has been suggested as a new method to treat UI. The aim of this article is to discuss whether there is evidence for a synergistic co‐contraction between TrA and PFM in women with UI, whether TrA contraction is as effective, or more effective than PFMT in treating UI and whether there is evidence to recommend TrA training as an intervention strategy.

Methods

A computerized search on PubMed, and hand searching in proceedings from the meetings of the World Confederation of Physical Therapy (1993–2007), International Continence Society and International Urogynecology Association (1990–2007) were performed.

Results

While a co‐contraction of the TrA normally occurs with PFM contraction, there is evidence that a co‐contraction of the PFM with TrA contraction can be lost or altered in women with UI. No randomized controlled trials (RCTs) were found comparing TrA training with untreated controls or sham. Two RCTs have shown no additional effect of adding TrA training to PFMT in the treatment of UI.

Conclusions

To date there is insufficient evidence for the use of TrA training instead of or in addition to PFMT for women with UI. Neurourol. Urodyn. 28:368–373, 2009. © 2009 Wiley‐Liss, Inc.
Predicting behavioral problems in craniopharyngioma survivors after conformal radiation therapy
Authors: Dolson Eugenia P. , Conklin Heather M. , Li Chenghong , Xiong Xiaoping , Merchant Thomas E.
Published: February 2009

Background

Although radiation therapy is a primary treatment for craniopharyngioma, it can exacerbate existing problems related to the tumor and pre‐irradiation management. Survival is often marked by neurologic deficits, panhypopituitarism, diabetes insipidus, cognitive deficiencies, and behavioral and social problems.

Procedure

The Achenbach Child Behavior Checklist (CBCL) was used to evaluate behavioral and social problems during the first 5 years of follow‐up in 27 patients with craniopharyngioma treated with conformal radiation therapy.

Results

All group averages for the CBCL scales were within the age‐typical range at pre‐irradiation baseline. Extent of surgical resection was implicated in baseline differences for the internalizing, externalizing, behavior problem and social scores. Significant longitudinal changes were found in internalizing, externalizing, behavior problem and school scores that correlated with tumor and treatment‐related factors.

Conclusions

The most common variables implicated in post‐irradiation behavioral and social problems were CSF shunting, presence of an Ommaya reservoir, diabetes insipidus, and low pre‐irradiation growth hormone levels. Pediatr Blood Cancer 2009;52:860–864. © 2009 Wiley‐Liss, Inc.
Studies on the development of biodegradable poly(HEMA)/Cloisite nanocomposites
Authors: Singhal Rahul , Datta Monika
Published: February 2009

The structural arrangement of molecules, ions, and other molecular species in the confined spaces of nanoscale pores and mineral interlayer are a key factor in understanding transport and reactivity in many technological and biological systems. In this respect, considerable research efforts have been focused on the design of nanoscale oral sustained‐ and controlled‐release drug delivery systems. Biodegradable polymers have long been of interest in controlled release technology because of the ability of these polymers to be reabsorbed by the body. There are not very many polymers which intercalate Cloisite, forming a good nanocomposite. The present study highlights some preliminary investigations on the synthesis of Cloisite and biodegradeable poly hydyroxyethyl methacrylate (PHEMA) nanocomposites. The nanocomposite were prepared by in situ intercalative polymerization of PHEMA within the Cloisite galleries and were characterized by spectral as well as morphological studies. POLYM. COMPOS., 2009. © 2009 Society of Plastics Engineers
Monitoring local fiber volume fraction in preform lap joints using Hall‐effect sensors
Authors: Samadi Reza , Robitaille Francois
Published: February 2009

This article describes the use of Hall‐effect sensors for monitoring local values of the fiber volume fraction in vacuum‐assisted resin transfer molding. Nonintrusive sensors mounted on the vacuum bag enable monitoring at a large number of points, under molding inserts and around geometrical features. Magnets can be mounted on the outer face of nonmetallic moulds. Low‐cost sensors can be discarded if damaged and the signal is unaffected by ambient conditions. The technique is demonstrated for lap‐jointed preforms made from two different reinforcements. All results presented in the article are validated using linear variable differential transducers. Although preform thickness is higher at superimposed lap joints, the fiber volume fraction is significantly larger in the joints. Interlaid continuous plies lead to a more reproducible behavior. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers
Effects of thermal cycling on static bearing strength of pin‐connected carbon/PPS composites
Authors: Yılmaz T. , Sınmazçelik T.
Published: February 2009

In this study, the effects of thermal cycling and water absorption on interlaminar shear strength (ILSS) and static bearing capacity of pin‐connected carbon fiber‐reinforced polyphenilenesulphide (PPS) matrix composites are investigated. Composite samples having [0o/90o]3s stacking sequence were used in the experiments and were exposed to 100 thermal cycles (one thermal cycle is composed of immersing and keeping samples in cold water and then immersing and keeping samples in hot water). ILSS and static bearing strength of pin connections were performed by using Instron 4411. According to the results, there are differences in ILSS values and pin‐connected static bearing capacities between the original samples and samples that are exposed to thermal cycling. Also the geometric parameters of end distance from the hole center (E), width of the plate (W), and pin diameter (D) remarkably affect the load bearing performance of the materials. In addition, according to the fractographic investigations using scanning electron microscope, it is observed that the fracture morphology of the samples is strongly affected by thermal cycling. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers
Organic functionalization of carbon nanofibers for composite applications
Authors: Paiva Maria C. , Novais Rui M. , Araújo Rui F. , Pederson Kristian K. , Proença Maria F. , Silva Carlos J.R. , Costa Carlos M. , Lanceros‐Méndez Senentxu
Published: February 2009

The present work reports the study of the effect of different chemical functionalization methods on the interfacial characteristics of the polymer composites formed. The chemically modified carbon nanofibers were blended with polypropylene (PP) and PP modified with maleic anhydride on a mini twin‐screw extruder. The functionalization methods were designed for minimum fiber damage and enhanced fiber/matrix interactions by chemical reaction of the functional groups introduced at the nanofibers surface with the maleic anhydride grafted at the PP. The degree of nanofiber functionalization was studied using thermogravimetric analysis. The composites were analyzed for nanofiber dispersion, mechanical properties, and electrical resistivity. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers
Interfacial strength in short glass fiber reinforced acrylonitrile‐butadiene‐styrene/polyamide 6 blends
Authors: Isitman Nihat Ali , Aykol Muratahan , Ozkoc Guralp , Bayram Goknur , Kaynak Cevdet
Published: February 2009

The purpose of this study is to derive the apparent interfacial shear strength of short glass fiber reinforced acrylonitrile‐butadiene‐styrene/polyamide 6 (PA6) blends with different PA6 contents. Tensile stress‐strain curves and fiber length distributions are utilized within a continuum micromechanics approach which involves a unified parameter for fiber length distribution efficiency represented as a function of strain. The unique combination of predicted micromechanical parameters is capable of accurately reproducing the mechanical response of the composite to applied strain. In this way, the influence of PA6 on interfacial zone is revealed by outcomes of the predictive method and validated by scanning electron microscopy observations. Favored intermolecular interactions in presence of PA6 chains result in the formation of a PA6 sheathing layer on glass fiber surfaces which in turn causes a drop in the apparent interfacial shear strength. The reason behind is shown to be the shift of the fracture zone from fiber/matrix interface to sheathing layer/matrixinterphase. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers
Characterization of nanocomposite laminates fabricated from aqueous dispersion of nanoclay
Authors: Aktas Levent , Altan M. Cengiz
Published: February 2009

Preparation of E‐glass/waterborne epoxy prepregs containing natural nanoclay and properties of their composites are presented. Prepregs were prepared by wetting randomly oriented, chopped glass fiber preforms with aqueous dispersion of EpiRez 3522‐W‐60 resin, dicyandiamide, 2‐methylimidazole and natural nanoclay (Cloisite® Na+). The nanoclay content of the aqueous dispersion was adjusted to yield final nanoclay contents of 0, 1, 2, and 4 wt%, whereas the glass fiber content is kept constant at 47 wt%. These prepregs were then used to fabricate disk‐shaped composite samples by APA2000 rheometer. Composite samples were tested for interlaminar shear strength, flexural stiffness, and glass transition temperature. The flexural stiffness was observed to increase by more than 26% over the range of nanoclay loading, despite a 13% decrease in interlaminar shear strength. Similarly, glass transition temperature increased from 89°C to above 94°C for the samples comprising 4 wt% nanoclay. X‐ray diffraction analyses indicated 48% increase in the gallery spacing suggesting strong intercalation of the nanoclay platelets by the epoxy matrix. Microstructural observations of the fracture surfaces and polished surfaces show significant differences in the matrix topology and fiber to matrix adhesion. The composites with higher nanoclay content depict uniform and submicron surface features implying homogenous dispersion of nanoclay. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers
Mass production of nanofibre assemblies by electrostatic spinning
Authors: Zhou Feng‐Lei , Gong Rong‐Hua , Porat Isaac
Published: February 2009

Electrospinning is a well‐established and intensively investigated methodology, and is currently the only known technique that can fabricate continuous nanofibres. The major challenge associated with electrospinning is its production rate, compared with that of conventional fibre spinning. However, the understanding of the scale‐up possibility of the electrospinning process is still in its infancy. Substantial up‐scaling of electrospinning may pave the way for applications of nanofibre assemblies (i.e.yarns) not accessible otherwise in conventional textile processes, such as weaving, knitting and braiding. Here we summarize recent advances regarding the enhancement of electrospinning throughput with special emphasis on multiple jets from multi‐needles and the free surface of polymer solutions. Copyright © 2009 Society of Chemical Industry
Analysis of pressure relief valve proof test data
Authors: Bukowski Julia V. , Goble William M.
Published: February 2009

This article reports on our statistical analysis of pressure relief valve (PRV) proof test data for the failure mode, fail‐to‐open, i.e., the PRV remains closed when actual pressure reaches or exceeds 150% of set pressure. Three data sets, from two Fortune 500 operating companies, which met the intent of the quality assurance of proof test data as documented by the Center for Chemical Process Safety Process Equipment Reliability Database (CCPS PERD)1 initiative, were analyzed. Although the original intent of our analysis focused solely on estimating the failure rate during the “useful life”2 of the equipment, it became apparent that the probability of failure on initial installation or reinstallation after proof test, and the need to address what constituted end of useful life were very significant. This article provides three important findings that are summarized as follows:

The statistical analysis of each data set predicted a 1–1.6% probability of initial failure where initial failure is understood to be at the time of initial installation or reinstallation after a proof test. This implies that most of the failures found during the useful life via proof test are pre‐existing failures from the time of installation or reinstallation rather than failures that occurred randomly after installation or reinstallation of the PRV.

Our calculations, based on the three independent data sets, led to consistent estimates of PRV useful‐life failure rates between 10−8 and 10−7 failures/h. Additionally, we compared our estimates from data analysis to the prediction of useful‐life failure rate for a particular PRV model using the Failure Modes Effects and Diagnostics Analysis (FMEDA) method. The prediction was consistent with the data estimates.

The data further indicated that the low useful‐life failure rate was not supported beyond a 4–5 year proof test interval as the threshold of wear‐out seemed to be approached.

The importance of these finding cannot be overestimated. When taking credit for a PRV in a risk assessment and in calculating the probability of failure on demand, both the initial probability of failing to open, as well as the probability of PRV failure due to the useful‐life failure rate, must be taken into account (the article discusses how to do this). Even then, the results are only defensible when it can be demonstrated that the proof test occurs before wear‐out (i.e., end of useful life) begins. © 2009 American Institute of Chemical Engineers Process Saf Prog, 2009
Synthesis of 5‐(4′‐carboxyphenyl)‐10,15,20‐tris‐(4 pyridyl)‐porphyrin and its peptidyl phosphonate derivatives
Authors: Habdas Jan , Boduszek Bogdan
Published: February 2009

The synthesis and characterization of three new 4‐pyridyl porphyrin‐peptidyl‐phosphonate compounds, containing a diphenyl 3‐pyridylmethyl‐phosphonate moiety, is described in this article. Nitrogen atoms in the pyridine rings of the obtained compounds were alkylated using methyl iodide, to give additional three, water soluble derivatives of these peptidyl‐porphyrin conjugates. All the synthesized compounds could serve as potential photosensitizers for the photodynamic therapy (PDT) method of tumor therapy and displayed activity as inhibitors of aminopeptidase N. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd.
Wavelength stabilized quantum dot lasers for high power applications
Authors: Pavelescu E. M. , Reithmaier J. P. , Kaiser W. , Weinmann P. , Kamp M. , Forchel A.
Published: February 2009

GaInAs/GaAs quantum dot lasers were developed with emission wavelengths of about 920 nm for high power high brightness applications. The laser structure and active dot layer was engineered in a way which allow a record‐low value of the temperature dependence of the emission wavelength with a temperature coefficient of 0.08 nm/K, i.e., about 4 times lower than quantum well lasers. Tapered lasers were fabricated with single lobe output in cw of more than 3 W. By additional distributed Bragg gratings, single mode output powers with >45 dB sidemode suppression and more than 1 W in cw could be obtained, which allow a stable single mode operation between 15–80 °C. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Formation of stacked linear InAs quantum dot arrays on InGaAsP/InP(100) by self‐organized anisotropic strain engineering
Authors: Sritirawisarn Nut , van Otten Frank W. M. , Eijkemans Tom J. , Nötzel Richard
Published: February 2009

We have previously demonstrated the formation of linear InAs quantum dot (QD) arrays based on self‐organized anisotropic strain engineering of InAs/InGaAsP superlattice (SL) templates on InP(100) by chemical beam epitaxy (CBE). The important step forward is the vertical stacking of the QD arrays with identical emission wavelength, realizing a three‐dimensionally self‐ordered QD crystal. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A relationship between all Atlantic hurricanes and those that make landfall in the USA
Authors: Coughlin K. , Bellone E. , Laepple T. , Jewson S. , Nzerem K.
Published: February 2009

The interannual prediction of the number of hurricanes to strike the US coastline is of vital interest to those who live on the coast, those who insure property along the coast and policy makers who make decisions about infrastructure and mitigation measures. Here it is shown that these predictions can be made more accurate when information about the total number of Atlantic Basin hurricanes is considered. The proportion of Atlantic hurricanes that make landfall in the USA is a measure of the relationship between landfalling and basin hurricane numbers. In order to use basin numbers to help make predictions of landfalling numbers, we must first investigate the nature of this relationship. Here we run a number of statistical tests and find that there is a significant change in the relative proportion of Atlantic hurricanes that hit the US coastline between the first and second halves of the 20th century. This difference is ostensibly due to the lack of basin observations in the earlier period. However, after 1948, the proportion of Atlantic hurricanes that hit the US coast shows no evidence of change. By assuming that the proportion is constant, we are able to then use information about the total number of hurricanes in the Atlantic Basin and make more accurate estimates of landfalling hurricane activity. Copyright © 2009 Royal Meteorological Society
Simultaneous estimation of covariance inflation and observation errors within an ensemble Kalman filter
Authors: Li Hong , Kalnay Eugenia , Miyoshi Takemasa
Published: February 2009

Covariance inflation plays an important role within the ensemble Kalman filter (EnKF) in preventing filter divergence and handling model errors. However the inflation factor needs to be tuned and tuning a parameter in the EnKF is expensive. Previous studies have adaptively estimated the inflation factor from the innovation statistics. Although the results were satisfactory, this inflation factor estimation method relies on the accuracy of the specification of observation error statistics, which in practice is not perfectly known. In this study we propose to estimate the inflation factor and observational errors simultaneously within the EnKF. Our method is first investigated with a low‐order model, the Lorenz‐96 model. The results show that the simultaneous approach works very well in the perfect model scenario and in the presence of random model errors or a small systematic model bias. For an imperfect model with large model bias, our algorithm may require the application of an additional method to remove the bias. We then apply our approach to a more realistic high‐dimension model, assimilating observations that have errors of different size and units. The SPEEDY model experiments show that the estimation of multiple observation error parameters is successful in retrieving the true error variance for different types of instruments separately. Copyright © 2009 Royal Meteorological Society
Sequential detection of change points for maintained systems using segmented point process models
Authors: Syamsundar A. , Naikan V. N. A.
Published: February 2009

Traditionally a change point model has been used for detection of change points and estimation of parameters, as an off line change detection procedure. A segmented point process model has been used to identify the changes off‐line in the failure process of a maintained system, with the process domain divided into segments at the points of change in the failure process, the individual segments being modelled by any of the usual point process models with unknown parameters. This paper proposes the use of the segmented point process model for sequentially identifying a change in the failure process of a maintained system due to a change in it's operating/maintenance environment. This method is demonstrated with field data from an industrial setting and its implications for the maintenance of the systems is brought out. Copyright © 2009 John Wiley & Sons, Ltd.
Simultaneous determination of inositol and inositol phosphates in complex biological matrices: quantitative ion‐exchange chromatography/tandem mass spectrometry
Authors: Liu Xiaodan , Villalta Peter W. , Sturla Shana J.
Published: February 2009

myo‐Inositol (Ins) and myo‐inositol phosphates (InsPs) are widely distributed in plants and animals. The evaluation of the distribution of Ins and InsPs in cells and plant sources can impact the understanding of their role in nutrition, cellular processes and diseases, and how they may be modulated by diet. We developed an anion‐exchange chromatography/tandem mass spectrometry (HPLC/ESI‐MS/MS) method for the separation and simultaneous quantitation of Ins and different naturally occurring phosphorylated inositol compounds. Chromatographic separation was achieved in 30 min on a commercial anion‐exchange column (0.5 × 150 mm) using a gradient of 200 mM ammonium carbonate buffer (pH 9.0) and 5% methanol in H2O. Analytes were identified by selective reaction monitoring using a triple quadrupole mass spectrometer in negative ion electrospray ionization mode. Adenosine 5′‐monophosphate was used as a general internal standard for quantitation. Detection is linear in the range of 0.25–400 pmol for Ins, InsP1, InsP4, and InsP5, 40–400 pmol for InsP2 and InsP3, and 60–400 pmol for InsP6, with a minimum r2 > 0.994. The limit of detection is 0.25 pmol with a signal‐to‐noise ratio of 10:1 for all analytes. The intra‐day and inter‐day variations were within 17% at three concentration levels. Recovery values for the seven analytes spiked into extraction solution or different matrices were between 63 and 121%. Using this approach, Ins and InsPs were measured in three different plant samples and in cultured cells, illustrating significant differences in the distribution of inositol compounds in food samples compared to cells and between cell types. Copyright © 2009 John Wiley & Sons, Ltd.
User Interface Migration of Microsoft Windows Applications
Authors: Gerdes John
Published: February 2009

When migrating a legacy application to a new platform, it is often necessary to recreate the application due to the unavailability of the source code. While there is extensive research addressing the migration of the program logic and modeling of user interface (UI) dynamics, there is limited research dealing with the recreation of the physical graphical user interface. This work investigates to what extent low‐level application programming interface calls and graphical comparison techniques can detect and identify objects in the executable version of the legacy application, and then recreate that UI in a new application. Results are reported from an empirical test of 20 applications from multiple software vendors. Findings indicate that the ability to identify objects is dependent on the development platform originally used to create the legacy application. Copyright © 2009 John Wiley & Sons, Ltd.
Invariant-based reasoning about parameterized security protocols
Authors: Mooij Arjan J.
Published: February 2009

We explore the applicability of the programming method of Feijen and van Gasteren to the domain of security protocols. This method addresses the derivation of concurrent programs from a formal specification, and it is based on common notions like invariants and pre- and post-conditions. We show that fundamental security concepts like secrecy and authentication can nicely be specified in this way. Using some small extensions, the style of formal reasoning from this method can be applied to the security domain. To demonstrate our approach, we discuss an authentication protocol and a public-key distribution protocol, and we deal with their composition. By focussing on a general setting where agents run the protocols multiple times, the nonce concept turns out to pop-up naturally. Although this work does not contain any new protocols, it does offer a new view on reasoning about security protocols.
Courvoisier’s Gallbladder: Law or Sign?
Authors: Fitzgerald J. Edward F. , White Matthew J. , Lobo Dileep N.
Published: February 2009

Background

Variously described as Courvoisier’s law, sign, or even gallbladder, this eponymous “law” has been taught to medical students since the publication of Courvoisier’s treatise in 1890.

Methods

We reviewed Courvoisier’s original “law,” the modern misconceptions surrounding it, and the contemporary evidence supporting and explaining his observations.

Results

Courvoisier never stated a “law” in the context of a jaundiced patient with a palpable gallbladder. He described 187 cases of common bile duct obstruction, observing that gallbladder dilatation seldom occurred with stone obstruction of the bile duct. The classic explanation for Courvoisier’s finding is based on the underlying pathologic process. With the presence of gallstones come repeated episodes of infection and subsequent fibrosis of the gallbladder. In the event that a gallstone causes the obstruction, the gallbladder is shrunken owing to fibrosis and is unlikely to be distensible and, hence, palpable. With other causes of obstruction, the gallbladder distends as a result of the back‐pressure from obstructed bile flow. However, recent experiments show that gallbladders are equally distensible in vitro, irrespective of the pathology, suggesting that chronicity of the obstruction is the key. Chronically elevated intraductal pressures are more likely to develop with malignant obstruction owing to the progressive nature of the disease. Gallstones cause obstruction in an intermittent fashion, which is generally not consistent enough to produce such a chronic rise in pressure.

Conclusion

We hope that reminding clinicians of Courvoisier’s actual observations will reestablish the usefulness of this clinical sign in the way he intended.
Bloodspot acylcarnitine and amino acid analysis in cord blood samples: efficacy and reference data from a large cohort study
Authors: Walter J. H. , Patterson A. , Till J. , Besley G. T. N. , Fleming G. , Henderson M. J.
Published: February 2009

Background:

In order to test the feasibility of cord blood screening for inherited metabolic disease, a two‐year cohort study of births in six obstetric units from five towns in the north of England was undertaken. These towns have a high prevalence of consanguineous marriages, largely among the immigrant Asian community. The purpose of the study was to determine whether early detection of metabolic disease was possible and whether early intervention would improve prognosis.

Methods:

Following parental consent, cord blood samples were collected at birth and analysed for acylcarnitine and amino acid profiles by tandem mass spectrometry in one of two laboratories. One laboratory used butylated derivatives, the other used underivatized samples. The same laboratories performed routine blood spot neonatal screening at 5–7 days of age on these babies. Patients with positive results were investigated and treated by a metabolic paediatrician as soon as possible.

Results:

24 983 births were examined. 12 952 samples were analysed as butyl derivatives, 12 031 samples were analysed underivatized. The following disorders were detected: medium‐chain acyl‐CoA dehydrogenase (MCAD) deficiency (1 case), 3‐methylcrotonyl‐CoA carboxylase (MCC) deficiency (2 cases), maternal carnitine transporter defect (2 cases), maternal MCC (1 case). The following disorders were diagnosed subsequently but were not detected by the cord blood screening: phenylketonuria (PKU) (1 case), maple syrup urine disease (MSUD) (2 cases), argininosuccinic aciduria (1 case), methylmalonic acidaemia (MMA) (1 case), glutaric aciduria type 2 (1 case), MCAD deficiency (2 cases), 3‐hydroxy‐3‐methylglutaryl‐CoA lyase deficiency (1 case). Comprehensive reference data for all analytes by both methods were obtained.

Conclusions:

Cord blood testing is of limited value in detecting inherited metabolic disease. The metabolites associated with most disorders examined were not elevated in cord blood. Some maternal disorders, carnitine transporter defect and 3‐methlycrotonyl‐CoA carboxylase deficiency, are detected. These remain of uncertain clinical significance. Comprehensive reference data have been obtained that will facilitate future interpretation of studies in cord blood.
Different requirements for physical dormancy release in two populations of Sophora alopecuroides relation to burial depth
Authors: Hu Xiao Wen , Wu Yan Pei , Wang Yan Rong
Published: February 2009

Most species of Fabaceae produce seeds with physical dormancy which was broken by some environmental factors in the field, yet for the mechanism of physical dormancy release in the natural condition is still poorly understood. In present study, seeds of Sophora alopecuroides from two populations were placed on the soil surface or buried at depths of 2 and 7 cm in the field and were exhumed at time intervals to assess the changes of dormancy. Also, microenvironments were simulated in the laboratory to determine the possible components (temperature, temperature fluctuation, and moisture) involved in physical dormancy release. The laboratory work indicated that wet heat is an important dormancy release mechanism for both populations; and dry heat for one of them, but showed no effects on the other one. Consistent with that, burial experiment showed seeds of two populations had two contrasting‐dormancy release patterns in the field. Most seeds of the dry heat sensitive population released dormancy but the other one remained dormant when seeds placed on the soil surface for 11 months (where seeds were exposed to dry heat but not wet heat). The difference of physical dormancy release pattern response to burial depth and simulated condition may attribute to seed coat color and hilum thickness which showed significantly different between two populations. This conclusion may improve understanding of physical dormancy release mechanism among populations and have a practical use for grassland management and weed control.
Protective Effects of EPA and Deleterious Effects of DHA on eNOS Activity in Ea hy 926 Cultured with Lysophosphatidylcholine
Authors: Tardivel Sylviane , Gousset‐Dupont Aurélie , Robert Véronique , Pourci Marie‐Luce , Grynberg Alain , Lacour Bernard
Published: February 2009

Oxidized low density lipoprotein (Ox‐LDL) is a well‐established risk factor in atherosclerosis and lysophosphatidylcholine (LysoPtdCho) is considered to be one of the major atherogenic component of Ox‐LDL. The purpose of this work was to investigate the effects of two membrane n‐3 long chain polyunsaturated fatty acids (n‐3 PUFAs), EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) compared to n‐6 PUFA, ARA (arachidonic acid), on the activation of endothelial NO synthase (eNOS) by histamine in Ea hy 926 endothelial cells incubated during 24 h in the presence or the absence of LysoPtdCho. DHA (50 μM) produced a ROS induction in cells and aggravated the LysoPtdCho‐induced oxidative stress. It did not modify the basal eNOS activity but impaired the stimulation of eNOS induced by histamine and was unable to correct the deleterious effect of LysoPtdCho on histamine‐stimulated eNOS activity or phosphorylation of Ser 1177. In contrast, EPA (90 μM) did not modify the ROS level produced in the presence or absence of LysoPtdCho or basal eNOS activity and the stimulating effect of histamine on eNOS. However, it diminished the deleterious effect of LysoPtdCho as well as on the histamine‐stimulated eNOS activity on the phosphorylation on Ser 1177 of eNOS. The beneficial effect of EPA but not DHA on endothelial eNOS activity in Ea hy 926 could be also partially due to a slight decrease in membrane DHA content in EPA‐treated cells. Consequently, the equilibrium between NO generated by eNOS and ROS due to oxidative stress could explain, in part, the beneficial effect of EPA on the development of cardiovascular diseases. By contrast ARA an n‐6 PUFA was devoid of any effect on ROS generation or eNOS activity in the basal state or after histamine‐induced stimulation. In vivo experiments should be undertaken to confirm these results.
Human Cdc25A phosphatase has a non‐redundant function in G2 phase by activating Cyclin A‐dependent kinases
Authors: Timofeev Oleg , Cizmecioglu Onur , Hu Entan , Orlik Thomas , Hoffmann Ingrid
Published: February 2009

Cdc25 phosphatases activate Cdk/Cyclin complexes by dephosphorylation and thus promote cell cycle progression. We observed that the peak activity of Cdc25A precedes the one of Cdc25B in prophase and the maximum of Cyclin/Cdk kinase activity. Furthermore, Cdc25A activates both Cdk1–2/Cyclin A and Cdk1/Cyclin B complexes while Cdc25B seems to be involved only in activation of Cdk1/Cyclin B. Concomitantly, repression of Cdc25A led to a decrease in Cyclin A‐associated kinase activity and attenuated Cdk1 activation. Our results indicate that Cdc25A acts before Cdc25B – at least in cancer cells, and has non‐redundant functions in late G2/early M‐phase as a major regulator of Cyclin A/kinase complexes.
A spectral sequence for theK-theory of tiling spaces
Authors: SAVINIEN JEAN , BELLISSARD JEAN
Published: February 2009

Let 𝒯 be an aperiodic and repetitive tiling of ℝdwith finite local complexity. We present a spectral sequence that converges to theK-theory of 𝒯 with page-2 given by a new cohomology that will be called PV in reference to the Pimsner–Voiculescu exact sequence. It is a generalization of the Serre spectral sequence. The PV cohomology of 𝒯 generalizes the cohomology of the base space of a fibration with local coefficients in theK-theory of its fiber. We prove that it is isomorphic to the Čech cohomology of the hull of 𝒯 (a compactification of the family of its translates).
Global attractors of analytic plane flows
Authors: LÓPEZ VÍCTOR JIMÉNEZ , PERALTA-SALAS DANIEL
Published: February 2009

In this paper the global attractors of analytic and polynomial plane flows are characterized up to homeomorphisms. Following on from previous results for continuous and differentiable dynamical systems, our theorem completes the characterization of the global attractors of plane flows.
On the critical dimensions of product odometers
Authors: DOOLEY ANTHONY H. , MORTISS GENEVIEVE
Published: February 2009

Mortiss introduced the notion of critical dimension of a non-singular action, a measure of the order of growth of sums of Radon derivatives. The critical dimension was shown to be an invariant of metric isomorphism; this invariant was calculated for two-point product odometers and shown to coincide, in certain cases, with the average coordinate entropy. In this paper we extend the theory to apply to all product odometers, introduce upper and lower critical dimensions, and prove a Katok-type covering lemma.
Multifractal analysis for disintegrations of Gibbs measures and conditional Birkhoff averages
Authors: FENG DE-JUN , SHU LIN
Published: February 2009

The paper is devoted to the study of the multifractal structure of disintegrations of Gibbs measures and conditional (random) Birkhoff averages. Our approach is based on the relativized thermodynamic formalism, convex analysis and, especially, the delicate constructions of Moran-like subsets of level sets.
Subdiffusive behavior generated by irrational rotations
Authors: HUVENEERS F.
Published: February 2009

We study asymptotic distributions of the sums yn(x)=∑ k=0n−1ψ(x+kα) with respect to the Lebesgue measure, where α∈ℝ−ℚ and where ψ is the 1-periodic function of bounded variation such that ψ(x)=1 if x∈[0,1/2[ and ψ(x)=−1 if x∈[1/2,1[. For every α∈ℝ−ℚ, we find a sequence (nj)j⊂ℕ such that $y_{n_j}/\sqrt j$ is asymptotically normally distributed. For n≥1, let zn∈(ym)m≤n be such that ‖zn‖L2=max m≤n‖ym‖L2. If α is of constant type, we show that zn/‖zn‖L2 is also asymptotically normally distributed. We give a heuristic link with the theory of expanding maps of the interval.
Embedding diffeomorphisms in flows in Banach spaces
Authors: ZHANG XIANG
Published: February 2009

This paper concerns the problem of embedding, in the flow of an autonomous vector field, a local diffeomorphism near a hyperbolic fixed point in a Banach space. To solve the problem, we first extend Floquet theory to Banach spaces, and then prove that two C∞ hyperbolic diffeomorphisms are formally equivalent if and only if they are C∞-equivalent. The latter result is a version, in the Banach space context, of a classical theorem by Chen.
Preimage pressure for random transformations
Authors: ZHU YUJUN , LI ZHIMING , LI XIAOHONG
Published: February 2009

In this paper, preimage pressure, which is based on the preimage structure of the system, is defined and studied for random transformations. We obtain analogs of many known results of preimage entropy and preimage pressure for deterministic cases in Cheng and Newhouse [Pre-image entropy. Ergod. Th. & Dynam. Sys.25 (2005), 1091–1113] and Zeng et al [Pre-image pressure and invariant measures. Ergod. Th. & Dynam. Sys.27 (2007), 1037–1052]. In particular, a variational principle is given and some applications of preimage pressure, such as the investigation of the invariant measures and the equilibrium states, are obtained.
Deformation of Brody curves and mean dimension
Authors: TSUKAMOTO MASAKI
Published: February 2009

The main purpose of this paper is to show that ideas of deformation theory can be applied to ‘infinite-dimensional geometry’. We develop the deformation theory of Brody curves. A Brody curve is a kind of holomorphic map from the complex plane to the projective space. Since the complex plane is not compact, the parameter space of the deformation can be infinite-dimensional. As an application we prove a lower bound on the mean dimension of the space of Brody curves.
On numbers having finite beta-expansions
Authors: ZAÏMI TOUFIK
Published: February 2009

Let β be a real number greater than one, and let ℤβ be the set of real numbers which have a zero fractional part when expanded in base β. We prove that β is a Pisot number when the set ℕβ−ℕβ−ℕβ is discrete, where ℕβ=ℤβ∩[0,∞[. We also give partial answers to some related open problems, and in particular, we show that β is a Pisot number when a sum ℤβ+⋯+ℤβ is a Meyer set.
Transitivity of surface dynamics lifted to Abelian covers
Authors: BOYLAND PHILIP
Published: February 2009

A homeomorphismfof a manifoldMis calledH1-transitive if there is a transitive lift of an iterate offto the universal Abelian cover$\tilde {M}$. Roughly speaking, this means thatfhas orbits which repeatedly and densely explore all elements ofH1(M). For a rel pseudo-Anosov map ϕ of a compact surfaceMwe show that the following are equivalent: (a) ϕ isH1-transitive, (b) the action of ϕ onH1(M) has spectral radius one and (c) the lifts of the invariant foliations of ϕ to$\tilde {M}$have dense leaves. The proof relies on a characterization of transitivity for twisted ℤd-extensions of a transitive subshift of finite type.
Non-hyperbolic ergodic measures for non-hyperbolic homoclinic classes
Authors: DÍAZ LORENZO J. , GORODETSKI ANTON
Published: February 2009

We prove that there is a residual subset 𝒮 in Diff1(M) such that, for everyf∈𝒮, any homoclinic class offcontaining saddles of different indices (dimension of the unstable bundle) contains also an uncountable support of an invariant ergodic non-hyperbolic (one of the Lyapunov exponents is equal to zero) measure off.