bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermal-wave interferometry of gas-liquid applied to a thermal-wave resonator cavity technique
Authors: Azmi B. Z. , Liaw H. S. , Abbas Z.
Published: June 2005

We propose the potential use of thermal-wave interferometry in measuring thermal diffusivities of two media with a thermal-wave resonator cavity technique. In the derived expression for a two-layer configuration, during cavity length probing of the upper medium, the physical and thermal properties of the lower medium were reasonably assumed to be independent of cavity length; hence each of the two slopes of signal versus cavity length actually determines the thermal diffusivity of the corresponding medium. In order to check the validity of the proposed model, we measure the thermal diffusivity of air and glycerol. A good linear relation of the amplitude and the phase with respect to cavity length in the thermally thick region of both media was observed, and the thermal diffusivities of air and glycerol obtained were close to the literature values. We suggest the potential application of thermal-wave resonator cavity technique to measure the thermal properties of a single-layer fluid in a general thermal condition where the advantage is that the signal-to-noise ratio is normally high compared to the thermally thick case. This can be achieved possibly by coating the pyroelectric transducer with a thermally thick solid material prior to any measurements.
Shot noise in x-ray measurements with p-i-n diodes
Authors: Spear Jonathan D.
Published: June 2005

The importance of shot noise is considered for situations in which p-i-n diodes monitor x-ray radiation. An expression for shot noise is derived in terms of the photon energy, the pair creation energy of the diode material, and the photocurrent. Statistical analysis shows that the Fano factor can be neglected for noise calculations. A lock-in amplifier measured the low frequency photocurrent noise from an unbiased silicon p-i-n photodiode that monitored radiation in the range of 6–16keV at a synchrotron beamline. With ordinary electronic amplification and shielding, shot noise dominated other noise sources for photocurrents exceeding about 5pA.
Linear rectangular air bearing based on squeeze film generated by ultrasonic oscillation
Authors: Oiwa Takaaki , Suzuki Ryosuke
Published: June 2005

This article reports an actively controllable linear motion air bearing that utilizes air films generated by ultrasonic oscillation. The films on eight bearing surfaces of a horn, which serves as the stator, lifted and guided a carriage consisting of four flat plates. Moreover, the oscillation that modulated the amplitude via the positioning signal varied with the thickness of the air film. Thus, this bearing regulated the position of the carriage in a vertical direction using a proportional and integral (PI) controller with a displacement sensor so that its motion error became zero. Furthermore, no pneumatic plant was needed in this bearing system. The motion straightness errors were 0.41μm peak to peak (p-p) in the vertical direction and 1.52μm p-p in the horizontal direction without compensation. Nonrepetitive motion errors were 0.34μm 2σ (two standard deviations) in the vertical direction and 0.39μm 2σ in the horizontal direction. The PI feedback control, in which a fiber optic displacement sensor measures the movement of a gauge block mounted on the carriage, decreased the vertical straightness error to 0.18μm p-p. The settling time for 0.2μm step positioning in the vertical direction was less than 0.1s. The positioning resolution was less than 20nm. Infinite stiffness under a 5.1N static load was obtained in the experiments.
“Dielectric relaxor” behavior of electroactive fluorinated polymers
Authors: Ang Chen , Yu Zhi
Published: June 2005

The dielectric spectra of poly(vinylidene fluoride-trifluoroethylene) copolymers and poly(vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene) terpolymers are studied in a wide temperature and frequency range with electric field. It is found that the dominant relaxation process displays a peculiar characteristic—a “dielectric relaxor” behavior, rather than a “ferroelectric relaxor” behavior reported in the current literature; furthermore, we show the experimental observation that the existence of nanometer scale crystals embedded in an amorphous matrix is the base of the dielectric relaxor behavior and high electroactive performance in these polymers.
Effect of n+-GaN subcontact layer on 4H–SiC high-power photoconductive switch
Authors: Zhu K. , Doğan S. , Moon Y. T. , Leach J. , Yun F. , Johnstone D. , Morkoç H. , Li G. , Ganguly B.
Published: June 2005

High-power photoconductive semiconductor switching devices were fabricated on 4H–SiC. In order to prevent current crowding, reduce the contact resistance, and avoid contact degradation, a highly n-doped GaN subcontact layer was inserted between the contact metal and the high resistivity SiC bulk. This method led to a two orders of magnitude reduction in the on-state resistance and, similarly, the photocurrent efficiency was increased by two orders of magnitude with the GaN subcontact layer following the initial high current operation. Both dry etching and wet etching were used to remove the GaN subcontact layer in the channel area. Wet etching was found to be more suitable than dry etching.
Visible-ultraviolet spectroscopic ellipsometry of lead zirconate titanate thin films
Authors: Lee Hosun , Kang Youn Seon , Cho Sang-Jun , Xiao Bo , Morkoç Hadis , Kang Tae Dong
Published: June 2005

We measured pseudodielectric functions in the visible-ultraviolet spectral range of Pb(ZrxTi1−x)O3 (x=0.2, 0.56, 0.82) (PZT) grown on platinized silicon substrate using the sol-gel method and also on (0001) sapphire using radio frequency sputtering method. Using a parametric optical constant model, we estimated the dielectric functions of the PZT thin films. Taking the second derivative of the fitted layer dielectric functions and using the standard critical point model, we determined the parameters of the critical points. In the second derivative spectra, the lowest bandgap energy peak near 4eV is fitted as a double peak for annealed PZTs associated with the perovskite phase. As-grown PZTs have mainly pyrochlore phase and the lowest bandgap is fitted as a single peak. We compared the bandgap energies with literature values.
The bacterial chemotactic response reflects a compromise between transient and steady-state behavior
Authors: Clark Damon A. , Grant Lars C.
Published: June 2005

Swimming bacteria detect chemical gradients by performing temporal comparisons of recent measurements of chemical concentration. These comparisons are described quantitatively by the chemotactic response function, which we expect to optimize chemotactic behavioral performance. We identify two independent chemotactic performance criteria: In the short run, a favorable response function should move bacteria up chemoattractant gradients; in the long run, bacteria should aggregate at peaks of chemoattractant concentration. Surprisingly, these two criteria conflict, so that when one performance criterion is most favorable, the other is unfavorable. Because both types of behavior are biologically relevant, we include both behaviors in a composite optimization that yields a response function that closely resembles experimental measurements. Our work suggests that the bacterial chemotactic response function can be derived from simple behavioral considerations and sheds light on how the response function contributes to chemotactic performance.
Substantial DNA damage from submicromolar intracellular hydrogen peroxide detected in Hpx
-
mutants of
Escherichia coli
Authors: Park Sunny , You Xiaojun , Imlay James A.
Published: June 2005

Since the discovery of catalase, it has been postulated that aerobic organisms generate enough oxidants to threaten their own fitness and, in particular, their genetic stability. An alternative is that these enzymes exist to defend the cell against more-abundant oxidants imposed by external sources. These hypotheses were tested directly through study of Hpx
-
(
katG katE ahpCF
) mutants of
Escherichia coli
, which lack enzymes to scavenge hydrogen peroxide (H
2
O
2
). These strains grew well in anaerobic medium but poorly when they were aerated. The Hpx
-
bacteria formed filaments and exhibited high rates of mutagenesis, both indicators of DNA damage. An additional
recA
mutation caused Hpx
-
cells to die rapidly upon aeration, even though the intracellular H
2
O
2
was <1 μM. Spin-trap experiments detected substantial hydroxyl radicals, and cell-permeable iron chelators eliminated both the phenotypic defects and hydroxyl-radical formation, confirming that the Fenton reaction was responsible. An Hpx
-
oxyR
strain exhibited even more DNA lesions than did the Hpx
-
mutant, indicating that the OxyR stress response induced protein(s) that suppressed DNA damage. One critical protein was Dps, an iron-sequestration protein, because Hpx
-
dps
mutants exhibited sensitivity similar to that of the Hpx
-
oxyR
mutant. These results reveal that aerobic
E. coli
generates sufficient H
2
O
2
to create toxic levels of DNA damage. Scavenging enzymes and controls on free iron are required to avoid that fate. The rate constant of the Fenton reaction measured at physiological pH was much higher than under the acidic conditions that were used to determine the commonly cited value.
Human thiopurine
S
-methyltransferase pharmacogenetics: Variant allozyme misfolding and aggresome formation
Authors: Wang Liewei , Nguyen Tien V. , McLaughlin Richard W. , Sikkink Laura A. , Ramirez-Alvarado Marina , Weinshilboum Richard M.
Published: June 2005

Thiopurine
S
-methyltransferase (TPMT) catalyzes the S-methylation of thiopurine drugs. TPMT genetic polymorphisms represent a striking example of the potential clinical value of pharmacogenetics. Subjects homozygous for

TPMT
*
3A

, the most common variant allele for low activity, an allele that encodes a protein with two changes in amino acid sequence, are at greatly increased risk for life-threatening toxicity when treated with standard doses of thiopurines. These subjects have virtually undetectable levels of TPMT protein. In this study, we tested the hypothesis that

TPMT
*
3A

might result in protein misfolding and aggregation. We observed that TPMT
*
3A forms aggresomes in cultured cells and that it aggregates
in vitro
, functional mechanisms not previously described in pharmacogenetics. Furthermore, there was a correlation among TPMT half-life values in rabbit reticulocyte lysate, aggresome formation in COS-1 cells, and protein aggregation
in vitro
for the three variant allozymes encoded by alleles that include the two

TPMT
*
3A

single-nucleotide polymorphisms. These observations were compatible with a common structural explanation for all of these effects, a conclusion supported by size-exclusion chromatography and CD spectroscopy. The results of these experiments provide insight into a unique pharmacogenetic mechanism by which common polymorphisms affect TPMT protein function and, as a result, therapeutic response to thiopurine drugs.
Slaved diffusion in phospholipid bilayers
Authors: Zhang Liangfang , Granick Steve
Published: June 2005

The translational diffusion of phospholipids in supported fluid bilayers splits into two populations when polyelectrolytes adsorb at incomplete surface coverage. Spatially resolved measurements using fluorescence correlation spectroscopy show that a slow mode, whose magnitude scales inversely with the degree of polymerization of the adsorbate, coexists with a fast mode characteristic of naked lipid diffusion. Inner and outer leaflets of the bilayer are affected nearly equally. Mobility may vary from spot to spot on the membrane surface, despite the lipid composition being the same. This work offers a mechanism to explain how nanosized domains with reduced mobility arise in lipid membranes.
An alternative interpretation of the amyloid Aβ hypothesis with regard to the pathogenesis of Alzheimer's disease
Authors: Marchesi Vincent T.
Published: June 2005

Alzheimer's disease is a complex neurodegenerative process that is believed to be due to the accumulation of short, hydrophobic peptides derived from amyloid precursor proteins by proteolytic cleavage. It is widely believed that these Aβ peptides are secreted into the extracellular spaces of the CNS, where they assemble into toxic oligomers that kill neurons and eventually form deposits of senile plaques. This essay explores the possibility that a fraction of these Aβ peptides never leave the membrane lipid bilayer after they are generated, but instead exert their toxic effects by competing with and compromising the functions of intramembranous segments of membrane-bound proteins that serve many critical functions. Based on the presence of shared amino acid sequences containing GxxG motifs, I speculate that accumulations of intramembranous Aβ peptides might affect the functions of amyloid precursor protein itself and the assembly of the PS1, Aph1, Pen 2, Nicastrin complex.
Mammalian electrophysiology on a microfluidic platform
Authors: Ionescu-Zanetti Cristian , Shaw Robin M. , Seo Jeonggi , Jan Yuh-Nung , Jan Lily Y. , Lee Luke P.
Published: June 2005

The recent development of automated patch clamp technology has increased the throughput of electrophysiology but at the expense of visual access to the cells being studied. To improve visualization and the control of cell position, we have developed a simple alternative patch clamp technique based on microfluidic junctions between a main chamber and lateral recording capillaries, all fabricated by micromolding of polydimethylsiloxane (PDMS). PDMS substrates eliminate the need for vibration isolation and allow direct cell visualization and manipulation using standard microscopy. Microfluidic integration allows recording capillaries to be arrayed 20 μm apart, for a total chamber volume of <0.5 nl. The geometry of the recording capillaries permits high-quality, stable, whole-cell seals despite the hydrophobicity of the PDMS surface. Using this device, we are able to demonstrate reliable whole-cell recording of mammalian cells on an inexpensive microfluidic platform. Recordings of activation of the voltage-sensitive potassium channel Kv2.1 in mammalian cells compare well with traditional pipette recordings. The results make possible the integration of whole-cell electrophysiology with easily manufactured microfluidic lab-on-a-chip devices.
Depletion of BRCA1 impairs differentiation but enhances proliferation of mammary epithelial cells
Authors: Furuta Saori , Jiang Xianzhi , Gu Bingnan , Cheng Eric , Chen Phang-Lang , Lee Wen-Hwa
Published: June 2005

Cumulative evidence indicates that breast cancer-associated gene 1 (
BRCA1
) participates in DNA damage repair and cell-cycle checkpoint control, serving as a tumor susceptibility gene to maintain the global genomic stability. However, whether BRCA1 has a direct role in cell proliferation and differentiation, two key biological functions in tumorigenesis, remains unclear. Here we demonstrate BRCA1 mediates differentiation of mammary epithelial cell (MEC) for acinus formation by using the
in vitro
3D culture system. Reduction of
BRCA1
in MEC by RNA interference impairs the acinus formation but enhances proliferation. Such aberrations can be rescued by expression of wild-type BRCA1 as well as a mutant at the RAD50-binding domain but not at the C-terminal BRCT domain, suggesting that the C-terminal BRCT domain has a critical role in these processes. Consistently, depletion of BRCA1 up-regulates the gene expression for proliferation but down-regulates that for differentiation. Moreover, application of the medium conditioned by differentiating normal MEC can reverse the phenotypes of differentiation-defective breast cancer cells bearing reduced BRCA1 functions. Our observation implies BRCA1 is involved in secretion of certain paracrine/autocrine factors that induce MEC differentiation in response to extracellular matrix signals, providing, in part, an explanation for the etiological basis of either sporadic or familial breast cancer due to the loss or reduction of BRCA1.
Directed evolution of
d
-sialic acid aldolase to
l
-3-deoxy-
manno
-2-octulosonic acid (
l
-KDO) aldolase
Authors: Hsu Che-Chang , Hong Zhangyong , Wada Masaru , Franke Dirk , Wong Chi-Huey
Published: June 2005

An efficient
l
-3-deoxy-
manno
-2-octulosonic acid (
l
-KDO) aldolase was created by directed evolution from the
Escherichia coli
d
-Neu5Ac (
N
-acetylneuraminic acid,
d
-sialic acid) aldolase. Five rounds of error-prone PCR and iterative screening were performed with sampling of 10
3
colonies per round. The specificity constant (
k
cat
/
K
m
) of the unnatural sugar
l
-KDO is improved to a level equivalent to the wild-type
d
-sialic acid aldolase for its natural substrate,
d
-Neu5Ac. The final evolved enzyme exhibits a >1,000-fold improved ratio of the specificity constant [
k
cat
/
K
m
(
l
-KDO)]/[
k
cat
/
K
m
(
d
-sialic acid)]. The protein sequence of the evolved aldolase showed eight amino acid changes from the native enzyme, with all of the observed changes occurring outside of the active site. Our effort demonstrates that an enzyme can be rapidly altered to accept enantiomeric substrates with screening of a small population of colonies iteratively toward the target substrate with improved catalytic efficiency. This work provides a method for the synthesis of enantiomeric sugars and for the study of enantiomeric catalysis affected by remote mutations.
The elasticity of an individual fibrin fiber in a clot
Authors: Collet Jean-Philippe , Shuman Henry , Ledger Robert E. , Lee Seungtaek , Weisel John W.
Published: June 2005

A blood clot needs to have the right degree of stiffness and plasticity to stem the flow of blood and yet be digestable by lytic enzymes so as not to form a thrombus, causing heart attacks, strokes, or pulmonary emboli, but the origin of these mechanical properties is unknown. Clots are made up of a three-dimensional network of fibrin fibers stabilized through ligation with a transglutaminase, factor XIIIa. We developed methods to measure the elastic moduli of individual fibrin fibers in fibrin clots with or without ligation, using optical tweezers for trapping beads attached to the fibers that functioned as handles to flex or stretch a fiber. Here, we report direct measurements of the microscopic mechanical properties of such a polymer. Fibers were much stiffer for stretching than for flexion, as expected from their diameter and length. Elastic moduli for individual fibers in plasma clots were 1.7 ± 1.3 and 14.5 ± 3.5 MPa for unligated and ligated fibers, respectively. Similar values were obtained by other independent methods, including analysis of measurements of fluctuations in bead force as a result of Brownian motion. These results provide a basis for understanding the origin of clot elasticity.
Collapse of single stable states via a fractal attraction basin: analysis of a representative metabolic network
Authors: Liu Junli , Crawford John W , Leontiou Konstantinos I
Published: June 2005

The impact of external forcing on an enzymatic reaction system with a single finite stable state is investigated. External forcing impacts on the system in two distinct ways: firstly, the reaction system undergoes a series of discontinuous changes in dynamical state. Secondly, a critical level of forcing exists, beyond which all finite states become unstable. It is shown that the results stem from the conditions for global stability of the system. Competition between the attractor for stable states and the unbounded states leads to a loss of integrity and the fractal fragmentation of the attraction basin for the finite state. The consequences of a fractal basin in this context are profound. Initial states which are infinitesimally close diverge to a finite and an unbounded state where only the finite state is consistent with biological functionality. Furthermore, above a critical forcing amplitude, the system does not converge to a finite state from any initial state, implying that there is no configuration of metabolite concentrations that is consistent with sustained evolution of the system. These results point to opportunities for constraining uncertainty in cell networks where nonlinear saturating kinetics form an important component.
Repeated evolution of net venation and fleshy fruits among monocots in shaded habitats confirms
a priori
predictions: evidence from an
ndhF
phylogeny
Authors: Givnish Thomas J , Pires J. Chris , Graham Sean W , McPherson Marc A , Prince Linda M , Patterson Thomas B , Rai Hardeep S , Roalson Eric H , Evans Timothy M , Hahn William J , Millam Kendra C , Meerow Alan W , Molvray Mia , Kores Paul J , O'Brien Heath E , Hall Jocelyn C , Kress W. John , Sytsma Kenneth J
Published: June 2005

We present a well-resolved, highly inclusive phylogeny for monocots, based on
ndhF
sequence variation, and use it to test
a priori
hypotheses that net venation and vertebrate-dispersed fleshy fruits should undergo concerted convergence, representing independent but often concurrent adaptations to shaded conditions. Our data demonstrate that net venation arose at least 26 times and was lost eight times over the past 90 million years; fleshy fruits arose at least 21 times and disappeared 11 times. Both traits show a highly significant pattern of concerted convergence (
p
<10
−9
), arising 16 times and disappearing four times in tandem. This phenomenon appears driven by even stronger tendencies for both traits to evolve in shade and be lost in open habitats (
p
<10
−13
–10
−29
). These patterns are among the strongest ever demonstrated for evolutionary convergence in individual traits and the predictability of evolution, and the strongest evidence yet uncovered for concerted convergence. The rate of adaptive shifts per taxon has declined exponentially over the past 90 million years, as expected when large-scale radiations fill adaptive zones.
Changes in maternal investment in eggs can affect population dynamics
Authors: Benton T.G , Plaistow S.J , Beckerman A.P , Lapsley C.T , Littlejohns S
Published: June 2005

The way that mothers provision their offspring can have important consequences for their offspring's performance throughout life. Models suggest that maternally induced variation in life histories may have large population dynamical effects, even perhaps driving cycles such as those seen in forest Lepidoptera. The evidence for large maternal influences on population dynamics is unconvincing, principally because of the difficulty of conducting experiments at both the individual and population level. In the soil mite,Sancassania berlesei, we show that there is a trade-off between a female's fecundity and the per-egg provisioning of protein. The mother's position on this trade-off depends on her current food availability and her age. Populations initiated with 250 eggs of different mean sizes showed significant differences in the population dynamics, converging only after three generations. Differences in the growth, maturation and fecundity of the initial cohort caused differences in the competitive environment for the next generation, which, in turn, created differences in their growth and reproduction. Maternal effects in one generation can therefore lead to population dynamical consequences over many generations. Where animals live in environments that are temporally variable, we conjecture that maternal effects could result in long-term dynamical effects.
Disease contact tracing in random and clustered networks
Authors: Kiss Istvan Z , Green Darren M , Kao Rowland R
Published: June 2005

The efficacy of contact tracing, be it between individuals (e.g. sexually transmitted diseases or severe acute respiratory syndrome) or between groups of individuals (e.g. foot-and-mouth disease; FMD), is difficult to evaluate without precise knowledge of the underlying contact structure; i.e. who is connected to whom? Motivated by the 2001 FMD epidemic in the UK, we determine, using stochastic simulations and deterministic ‘moment closure’ models of disease transmission on networks of premises (nodes), network and disease properties that are important for contact tracing efficiency. For random networks with a high average number of connections per node, little clustering of connections and short latency periods, contact tracing is typically ineffective. In this case, isolation of infected nodes is the dominant factor in determining disease epidemic size and duration. If the latency period is longer and the average number of connections per node small, or if the network is spatially clustered, then the contact tracing performs better and an overall reduction in the proportion of nodes that are removed during an epidemic is observed.
What happened in 1953? The Big Flood in the Netherlands in retrospect
Authors: Gerritsen Herman
Published: June 2005

During the weekend of Saturday 31 January to Sunday 1 February 1953, a storm tide raged across the northwest European shelf and flooded the low-lying coastal areas of the countries around the North Sea. The peak high waters occurred during the night and the storm surprised many people in their sleep. The resulting disaster in terms of loss of life and damage to infrastructure was enormous. In the Netherlands, 1836 people fell victim to the flood; in the UK and Belgium, the casualities were 307 and 22, respectively. The large number of fatalities in the Netherlands was related to the fact that much of the affected area is below sea-level.

This paper focuses on the case of the Netherlands. It discusses the history of land reclamation, and the fact that living in low-lying areas protected by dykes, often below sea-level, is an accepted fact of life in the Netherlands. The historical approach to dyke maintenance is then outlined, and the state of the dykes in the early twentieth century and after the war is discussed. The characteristics of the storm and the flood are discussed, along with people's experiences of the first hours and days following the flood. The impact of this human stress has often been lasting—many survivors continue to live with daily memories of the flood. Attention is given to the large-scale rescue and relief efforts, the closure of the dykes during the following nine months and the concept of the Delta Plan, designed to prevent such a large-scale disaster ever happening again. Although the 1953 storm was indeed a low probability event leading to very high storm-induced water-levels, and occurred in combination with spring tide, several arguments are presented that explain why this flood turned into a disaster of such a large scale. Equally, the question is raised whether the disaster could have been prevented. The paper concludes by noting the importance of awareness and preparedness in order to prevent a future storm threat of this scale turning into a disaster of the scope of the Big Flood of 1953.
The east coast Big Flood, 31 January–1 February 1953: a summary of the human disaster
Authors: Baxter Peter J
Published: June 2005

The Big Flood was the worst natural disaster to befall Britain during the twentieth century, and the scale of its human impact was due to the lack of adequate disaster preparedness. The 307 deaths on land were caused by drowning or from the effects of exposure. Two-thirds occurred in four clusters along the shoreline and mainly comprised inhabitants of post-war prefabricated buildings, bungalows and chalets, with the highest mortality among the elderly. The emergency response was spontaneous and community led, with the main search and rescue completed before central government became involved. No individuals or agencies were blamed for the neglected state of the flood defences or the absence of warnings, along with the post-war shortage of adequate housing, which were the main causes of vulnerability. The media played a limited role, and television was in its infancy. Mental health impacts were either self-limiting or failed to be articulated in a society recovering from the Second World War. The major mitigating factors included the empathetic response of people, locally and nationally, as well as the availability of armed forces personnel based in East Anglia, whose actions played a decisive part in the battle against the sea. The major legacies of the Big Flood were a coastal flood forecasting system, a more scientific approach to sea defences and the building of the Thames barrier.
Windstorm and storm surges in Europe: loss trends and possible counter-actions from the viewpoint of an international reinsurer
Authors: Berz Gerhard
Published: June 2005

Windstorm disasters (including storm surges) account for about one-third of all natural disasters throughout the world (by number, fatalities and economic losses), but for more than two-thirds of the corresponding insured losses. Trend analyses reveal that major windstorm disasters and the losses generated by them have increased drastically in recent decades. Risk partnership between the state, the affected population and the insurance industry assumes a key role with regard to the windstorm hazard. Scientists, engineers and insurers must work together in formulating their requirements and shaping them in such a way that politicians can derive clearly recognizable policy options (e.g. land-use, restrictions, design-code adjustments) from them. Another important aspect is stepping up the efforts being made towards curbing climate change, which will, otherwise, exacerbate the risk in the future.
Management planning and control
Authors: Herremans Irene M. , Isaac Robert G.
Published: June 2005

Purpose

The purpose of this paper is to develop propositions for empirical validation regarding appropriate management planning and control systems (MPACS) in knowledge‐intensive organizations.

Design/methodology/approach

The propositions were developed from interviews with members of a knowledge‐intensive virtual organization that is known for its innovative practices regarding intellectual capital (IC) development and surveys from low to middle range managers, using a semi‐structured questionnaire, from a variety of companies. Trends in responses permitted us to identify issues of importance in developing innovative MPACS for knowledge‐intensive companies.

Findings

The paper proposes that two variables, the level of IC intensity and the uncertainty of knowledge, are important for determining the degree of adaptive versus generative characteristics that an organization's MPACS should contain. Regarding IC, the paper further proposes that organizations must give careful thought to ensure that both adaptive and generative characteristics are aligned with four MPACS elements of focus, commitment, capability, and learning.

Originality/value

As organizations develop programs to realize the potential from their intellectual capital, many fail to develop MPACS that are appropriate for knowledge‐intensive environments. MPACS should support knowledge creation, as well as knowledge sharing, and contain elements of both adaptive and generative systems.
Phylogeny of the Pantomorus–Naupactus complex based on morphological and molecular data (Coleoptera: Curculionidae)
Authors: Scataglini María A. , Lanteri Analía A. , Confalonieri Viviana A.
Published: June 2005

The Pantomorus–Naupactus complex is a Neotropical group of broad‐nosed weevils (Coleoptera: Curculionidae) including several parthenogenetic species usually assigned to the genera Naupactus Dejean, Pantomorus Schoenherr, Asynonychus Crotch, Aramigus Horn, Eurymetopus Schoenherr and Graphognathus Buchanan. Sixteen species were studied to test hypotheses on the monophyly of these genera, and on the origin of the parthenogenetic lineages. A matrix of 30 morphological characters and 999 positions of the Cytochrome Oxidase I gene, was analyzed with separate partitions and simultaneously, under equal and implied weights, and with different transversion/transitions costs. The ILD test indicates that the incongruence between the molecular and morphological data is not significant. Under equal weights, the molecular data resulted in a single tree and morphology in 34 trees; under implied weights morphology gave a different tree, and under TV:TS ≥ 4:1 molecular and combined analyses resulted in the same optimal tree. According to the latter, Naupactus includes Graphognathus, and is thus paraphyletic and basal regarding remaining genera, Pantomorus is polyphyletic and includes Aramigus and Asynonychus, and Eurymetopus is monophyletic. The species in which apomictic parthenogenesis has been verified (Aramigus tessellatus, Asynonychus cervinus and Graphognathus lecuoloma), belong to different clades of the Pantomorus‐Naupactus complex, with basal sexual relatives.

© The Willi Hennig Society 2005.
A review of long‐branch attraction
Authors: Bergsten Johannes
Published: June 2005

The history of long‐branch attraction, and in particular methods suggested to detect and avoid the artifact to date, is reviewed. Methods suggested to avoid LBA‐artifacts include excluding long‐branch taxa, excluding faster evolving third codon positions, using inference methods less sensitive to LBA such as likelihood, the Aguinaldo et al. approach, sampling more taxa to break up long branches and sampling more characters especially of another kind, and the pros and cons of these are discussed. Methods suggested to detect LBA are numerous and include methodological disconcordance, RASA, separate partition analyses, parametric simulation, random outgroup sequences, long‐branch extraction, split decomposition and spectral analysis. Less than 10 years ago it was doubted if LBA occurred in real datasets. Today, examples are numerous in the literature and it is argued that the development of methods to deal with the problem is warranted. A 16 kbp dataset of placental mammals and a morphological and molecular combined dataset of gall waSPS are used to illustrate the particularly common problem of LBA of problematic ingroup taxa to outgroups. The preferred methods of separate partition analysis, methodological disconcordance, and long branch extraction are used to demonstrate detection methods. It is argued that since outgroup taxa almost always represent long branches and are as such a hazard towards misplacing long branched ingroup taxa, phylogenetic analyses should always be run with and without the outgroups included. This will detect whether only the outgroup roots the ingroup or if it simultaneously alters the ingroup topology, in which case previous studies have shown that the latter is most often the worse. Apart from that LBA to outgroups is the major and most common problem; scanning the literature also detected the ill advised comfort of high support values from thousands of characters, but very few taxa, in the age of genomics. Taxon sampling is crucial for an accurate phylogenetic estimate and trust cannot be put on whole mitochondrial or chloroplast genome studies with only a few taxa, despite their high support values. The placental mammal example demonstrates that parsimony analysis will be prone to LBA by the attraction of the tenrec to the distant marsupial outgroups. In addition, the murid rodents, creating the classic “the guinea‐pig is not a rodent” hypothesis in 1996, are also shown to be attracted to the outgroup by nuclear genes, although including the morphological evidence for rodents and Glires overcomes the artifact. The gall wasp example illustrates that Bayesian analyses with a partition‐specific GTR + Γ + I model give a conflicting resolution of clades, with a posterior probability of 1.0 when comparing ingroup alone versus outgroup rooted topologies, and this is due to long‐branch attraction to the outgroup.

© The Willi Hennig Society 2005.
Interleukin‐4 production by human alveolar macrophages
Authors: Pouliot P. , Turmel V. , Gélinas É. , Laviolette M. , Bissonnette É. Y.
Published: June 2005

Background
IL‐4 is a key factor for T helper type 2 (Th2) differentiation and Ig class switching to IgE and IgG4 during the development of immune responses. IL‐4 is produced by T cells, mast cells, basophils, and eosinophils. However, there is also evidence suggesting that rat alveolar macrophages (AMs) produce IL‐4.

Objective
Given the importance of AMs and Th2‐related diseases in the lung, we investigated the production of IL‐4 by human AMs.

Methods
Human AMs were isolated from bronchoalveolar lavage, purified, and IL‐4 production was investigated at mRNA and protein levels using real‐time PCR, flow cytometry, immunocytochemistry, and ELISA. The presence of IL‐4 was investigated in subjects with asthma or asymptomatic airway hyper‐responsiveness, and in normal non‐smokers.

Results
IL‐4 and IL‐4δ2 (a splice variant found in other IL‐4 producing cells) mRNAs were found in all these subjects, but IL‐4 expression could not be correlated with a particular disease. Protein production was verified by immunocytochemistry and flow cytometry analysis demonstrating, respectively, up to 69% and 59% positive AMs, regardless of the subject condition. Furthermore, phorbol‐12‐myristate‐13‐acetate and calcium ionophore stimulated the release of IL‐4 after 48 h treatment in the presence of anti‐IL‐4 receptor antibody.

Conclusion
Our results show for the first time that IL‐4 and IL‐4δ2 mRNA are expressed and IL‐4 protein produced and released by human AMs, suggesting a contribution of these cells in the modulation of Th2 immune response.
Persistent airway hyper‐responsiveness and inflammation inToxocara canis‐infected BALB/c mice
Authors: Pinelli E. , Withagen C. , Fonville M. , Verlaan A. , Dormans J. , Van Loveren H. , Nicoll G. , Maizels R. M. , Van Der Giessen J.
Published: June 2005

BackgroundInfection withToxocara canis, the roundworm of dogs, has been associated with asthmatic manifestations. Clinical symptoms such as wheezing, coughing and episodic airflow obstruction have been described for patients infected with this helminth.

ObjectiveIn order to characterize the effect ofT. canisinfection on the lungs, we monitored immune responses, pulmonary pathology and lung function over a period of 60 days in BALB/c mice.

MethodsInfection was performed by a single oral administration of 1000T. canisembryonated eggs. Airway responsiveness was measured in conscious, unrestrained mice at 7, 14, 30 and 60 days post‐infection (p.i.).

ResultsInfection of mice resulted in airway hyper‐responsiveness (AHR) that persisted up to 30 days p.i. Pulmonary inflammation as well as increased levels of IgE and eosinophils in bronchoalveolar lavage (BAL) persisted up to 60 days p.i. Cytokine analysis in BAL indicated increased levels of IL‐5 at day 7 and 14 p.i., whereas the levels of IL‐2, IFN‐γ, IL‐4 and IL‐10 did not differ from those of uninfected controls.Toxocara‐specific stimulation of spleen cells using recombinant TES‐70 protein resulted in the induction of IL‐5 at day 7 and 14 p.i. and IL‐10 at day 14 p.i. Production of all other cytokines did not differ from that of uninfected controls. Evaluation of larval burden revealed thatT. caniswas still present in the lungs of infected mice at 60 days p.i.

ConclusionThe presence ofToxocaralarva in the lungs at 60 days p.i. following a single infection could explain the persistent pulmonary inflammation, airway hyper‐reactivity, eosinophilia and increased IgE production observed inT. canis‐infected BALB/c mice.
Fecal microbiota in sensitized wheezy and non‐sensitized non‐wheezy children: a nested case–control study
Authors: Murray C. S. , Tannock G. W. , Simon M. A. , Harmsen H. J. M. , Welling G. W. , Custovic A. , Woodcock A.
Published: June 2005

Background
It has been suggested that intestinal microbiota of allergic and non‐allergic children differs in composition, and that microbiota–immune system interactions may predispose children to develop sensitization. Previous studies have examined fecal microbiota of allergic children with atopic dermatitis, but little is known about that of atopic wheezy children.

Objective
To investigate the composition of the fecal microbiota of young sensitized wheezy and non‐sensitized non‐wheezy children, using molecular methods.

Methods
Within the context of a prospective birth cohort, we carried out a nested case–control study of sensitized wheezy children (cases) and non‐sensitized non‐wheezy controls. Cases and controls were matched for age, sex, parental atopy, allergen exposure, and pet ownership. We evaluated the composition of fecal microbiota by nucleic acid‐based methods (PCR combined with denaturing gradient gel electrophoresis and quantification of bifidobacteria by fluorescent in situ hybridization).

Results
Thirty‐three case–control pairs (mean age 4.4 years) provided stool samples. Comparison of total bacterial community profiles showed that each child had a unique fecal microbiota (mean Dice's similarity coefficient 22%, range 3.3–60.8%). There was no difference between the groups in prevalence of Lactic Acid bacteria (12/33 vs. 11/33, P=0.8) or bifidobacteria (30/33 vs. 31/33, P=1.00, cases vs. controls). The bifidobacterial species detected were similar in both groups. The percentage of bifidobacteria in total fecal microflora was no different between cases (median 1.7%, range 0–20.8%) and controls (1.9%, 0–18.2%, P=0.7). However, cases with eczema had significantly fewer bifidobacteria (median 1.6%, range 0–4.8%) than their controls (4.0%, 1.9–18.2%, P=0.05).

Conclusion
We found no differences in fecal microbiota composition between sensitized wheezy and non‐sensitized, non‐wheezy children aged 3–5 years using nucleic acid‐based methods. Differences appear to be isolated to those allergic children with eczema.
Epicutaneous exposure to peanut protein prevents oral tolerance and enhances allergic sensitization
Authors: Strid J. , Hourihane J. , Kimber I. , Callard R. , Strobel S.
Published: June 2005

Background
Food allergies are an important cause of life‐threatening hypersensitivity reactions. Oral tolerance can be considered the default immune response to dietary antigens, with immune deviation resulting in allergic sensitization. However, primary sensitization to food allergens may not solely be through the gastrointestinal mucosa, as strong T‐helper type 2 (Th2)‐biased immunity can result from exposure to protein allergens on barrier‐disrupted skin.

Objective
The purpose of this study was to examine whether exposure to allergens through the skin may interfere with the normal development of oral tolerance and promote allergic sensitization to food proteins.

Methods
Female BALB/c mice were exposed epicutaneously to peanut protein and induction of systemic oral tolerance through high dose feeds of peanut protein was subsequently assessed. Other mice were rendered tolerant prior to epicutaneous peanut exposure. Sensitivity to peanut was determined by assessing delayed‐type hypersensitivity, proliferative, cytokine and antibody responses.

Results
Epicutaneous exposure to peanut protein induced potent Th2‐type immunity with high levels of IL‐4 and serum IgE. Primary skin exposure prevented the subsequent induction of oral tolerance to peanut in an antigen‐specific manner. Upon oral challenge, mice became further sensitized and developed strong peanut‐specific IL‐4 and IgE responses. Furthermore, animals with existing tolerance to peanut were partly sensitized following epicutaneous exposure.

Conclusion
Epicutaneous exposure to peanut protein can prevent induction of oral tolerance, and may even modify existing tolerance to peanut. Epidermal exposure to protein allergens selectively drives Th2‐type responses, and as such may promote sensitization to food proteins upon gastrointestinal exposure.
Oral aspirin challenges in patients with a history of intolerance to single non‐steroidal anti‐inflammatory drugs
Authors: Asero R.
Published: June 2005

Background
In the clinical practice patients with a history of acute urticaria induced by a single non‐steroidal anti‐inflammatory drug (NSAID) and seeking for safe alternative drugs generally undergo tolerance tests with alternative NSAIDs that have little or no cyclooxygenase‐1 (COX‐1) enzyme inhibitory activity. This practice does not allow for the detection of single NSAID reactors and may lead to unnecessary avoidance of many potentially useful NSAIDs.

Objective
Evaluate aspirin challenge as a means to distinguish single from multiple NSAID intolerance in patients with a clinical history of acute urticaria induced by a single NSAID.

Methods
One hundred and seventeen otherwise normal subjects with a history of acute urticaria following the ingestion of a single NSAID (pyrazolones (n=58), nimesulide (n=17), propionic acid derivatives (n=13), aryl acetic acid derivatives (n=14), acetaminophen (n=9), piroxicam (n=5), and indometacin (n=1)) underwent single‐blind placebo‐controlled oral challenges with aspirin. Aspirin‐intolerant subjects underwent further tolerance tests drugs exerting little or no inhibitory activity on COX‐1 enzyme (including paracetamol, nimesulide, rofecoxib, tramadol, and floctafenine).

Results
Aspirin induced urticaria in 28/117 (24%) patients. Five out of 28 (18%) aspirin reactors did not tolerate alternative NSAID on subsequent oral challenges.

Conclusion
In subjects with a history of urticaria induced by a single NSAID (other than aspirin) the diagnostic workup should start with an aspirin challenge in order to detect single/multiple NSAID reactors.
Nutrient concentrations in a Littorella uniflora community at higher CO2 concentrations and reduced light intensities
Authors: ANDERSEN TROELS , PEDERSEN OLE , ANDERSEN FREDE Ø.
Published: June 2005

1. Oligotrophic softwater lakes represent a special type of aquatic ecosystem with unique plant communities where generalisations from other aquatic plant communities to rising CO2 in the water column may not apply.

2. In the present study, we set up large in situ mesocosms and supporting laboratory experiments with isoetid vegetation (Littorella uniflora) where water column CO2 and light could be manipulated in order to test whether (i) light and CO2 availability affect nutrient concentrations in isoetid vegetation, and (ii) if changes in light and CO2 climate affect fluxes of inorganic nitrogen (N) and phosphorus (P) from sediment to water column, which potentially could result in increased growth of epiphytic algae.

3. The results showed that the standing stocks of phosphorus and nitrogen in the L. uniflora vegetation were significantly influenced by CO2 concentration and light intensity. Both standing stocks of P and N were significantly higher in the mesocosm treatments with high CO2 concentration than in those at low CO2 concentration. Similarly, standing stocks of P and N enhanced with increasing light intensity.

4. Measurements of nutrient fluxes both in the field and the laboratory did not show any significant release of nutrients to the water column from plants or sediments at any of the light or CO2 treatments. However, mats of epiphytic algae developed from the beginning of June to late September and caused a light reduction for the isoetid vegetation.

5. Increasing CO2 concentrations in the water column may over time potentially result in a change in soft water plant communities.