bluuebunny/crossref_metadata_2025 huggingface dataset:
How various ‘cultures of fitness’ shape subjective experiences of growing older
Authors: PAULSON SUSAN
Published: February 2005

Is growing older a process of decline or of keeping active? Foucauldian theory suggests particular regimes of fitness will discipline ageing bodies in distinctively different ways. This paper reports a comparative ethnographic and qualitative interview study of a ‘fitness exercise’ and a ‘dance exercise’ group for the over-fifties. The findings demonstrate the ways in which contradictory cultural discourses in the fitness training curricula are associated with different subjective experiences of physical and psychological ageing. The ‘fitness exercise’ group focused on individual fitness levels for the ageing body in the terms of the cultural discourses of health and physiology. The ‘dance exercise’ group focused on the graceful ageing body in the terms of the cultural discourses of the psycho-social benefits of movement in relation to others. The study combined phenomenological and social constructionist dimensions, and exemplifies the ways in which the subjective experience of the ageing body may become embedded in particular cultures of fitness.
Analogue modeling of instabilities in crater lake hydrothermal systems
Authors: Vandemeulebrouck Jean , Stemmelen Didier , Hurst Tony , Grangeon Jacques
Published: February 2005

We carried out analogue experiments on two‐phase boiling systems, using a porous vertical cylinder, saturated with water. The base of the cylinder was heated, and the top was cooled, as in a natural hydrothermal system. Previous work had shown that once the two‐phase zone reached a certain level, thermal instabilities would develop. We made measurements of the acoustic energy related to boiling, and we found that high levels of acoustic noise were associated with the part of the cycle in which there was upward water movement. We repeated our experiments with a cooling water tank at the top of the system, representing a crater lake. This showed that periodic thermal instabilities still developed in this situation. We then compared our analogue measurements to two natural systems known to exhibit periodic behavior. There is good agreement between the thermal and acoustic cycling seen in our model and the observations made at Inferno Crater Lake in the Waimangu Geothermal area, New Zealand, whose level cycles by nearly 10 m, with a typical period of 38 days. Particularly notable is how in both systems high levels of acoustic noise are associated with rising water level. The much larger Ruapehu Crater Lake, also in New Zealand, cycled with a period of several months to a year for over a decade prior to the 1995 eruption. Strong acoustic and seismic energy usually occurred just before the lake temperature started to rise. This suggests a slightly different model, in which the increasing two‐phase flow zone triggers more general convection once it reaches the base of the lake.
Assessment of the importance of ice‐shelf buttressing to ice‐sheet flow
Authors: Dupont T. K. , Alley R. B.
Published: February 2005

Reduction or loss of a restraining ice shelf will cause speed‐up of flow from contiguous ice streams, contributing to sea‐level rise, with greater changes from ice streams that are wider, have stickier beds, or have higher driving stress. Loss of buttressing offsetting half of the tendency for ice‐stream/ice‐shelf spreading for an ice stream similar to Pine Island Glacier, West Antarctica is modeled to contribute at least 1 mm of sea‐level rise over a few decades. These results come from a new, simple model that includes relevant stresses in a boundary‐layer formulation, and allows rapid estimation of ice‐shelf impacts for a wide range of configurations.
Assessing thermal effects on magnetic fabrics of sedimentary rocks: Results from synthetic and natural samples
Authors: Li Yong‐Xiang , Kodama Kenneth P.
Published: February 2005

In order to examine thermal effects on magnetic fabrics, particularly remanence fabrics that test the accuracy of paleomagnetic records, the pre‐ and post‐heating magnetic fabrics of synthetic (magnetite+CaF2) and natural samples were compared. The natural samples were collected from a thermally remagnetized, baked zone of the Triassic Passaic Fm. in southeastern Pennsylvania, USA and their magnetic fabrics were compared with those from the unremagnetized Passaic country rocks. The unheated synthetic and natural samples display predominantly oblate magnetic susceptibility and remanence fabrics. The heated synthetic samples yield oblate AMS and AAR fabrics; whereas the remagnetized Passaic rocks show random AMS fabrics, but exhibit depositional remanence fabrics. Apparently, natural samples we studied lost their initial AMS fabrics but inherited their initial depositional remanence fabrics during thermal remagnetization. Thus, the presence of oblate fabrics may not uniquely indicate a primary remanence. The disagreement between AMS and AAR fabrics could indicate a possible remagnetization.
Elevated mercury measured in snow and frost flowers near Arctic sea ice leads
Authors: Douglas T. A. , Sturm M. , Simpson W. R. , Brooks S. , Lindberg S. E. , Perovich D. K.
Published: February 2005

Elevated mercury concentrations have been reported in arctic coastal snow far from emission sources. The mercury is deposited during mercury depletion events (MDEs), a set of photochemical atmospheric reactions involving reactive halogens. The highest mercury concentrations are clustered near the coast, leading to speculation that sea ice or sea ice leads play a role in MDEs. The nature of this connection is not fully understood. We report mercury concentrations up to 820 ng/L in snow and frost flowers along sea ice leads near Barrow, Alaska. These concentrations are nine times higher than values from nearby coastal snow and are almost half of the mercury maximum contaminant level in United States drinking water. The high values were found only near leads that had convective plumes above open water suggesting that the same processes that produce a supersaturated environment for water vapor near sea ice leads may be instrumental in mercury deposition.
Relations of polarized scattering signatures observed by the TRMM Microwave Instrument with electrical processes in cloud systems
Authors: Prigent Catherine , Defer Eric , Pardo Juan R. , Pearl Cindy , Rossow William B. , Pinty Jean‐Pierre
Published: February 2005

The polarized scattering signatures observed in convective cloud systems with the Tropical Rainfall Measuring Mission (TRMM) Microwave Instrument are analyzed. In particular, and in contrast to the positive polarization difference (TbV‐TbH > 0) observed when scattering by large ice particles is important, we also find a negative polarization difference. Radiative transfer simulations show that such a polarization difference can be explained by relatively large, mostly vertically oriented, non‐spherical particles but not by horizontally or randomly oriented non‐spherical particles. We establish a relationship between the occurrence of the negative polarization difference signature and electrical activity in the cloud using coincident observations by the Lightning Imaging Sensor also on board TRMM. The negative polarization difference is thus related to non‐spherical particles that are mostly vertically oriented as revealed by the lightning activity. This result confirms that a careful analysis of passive microwave observations over clouds provides valuable information about the cloud ice phase.
An assessment of the ability of three‐dimensional air quality models with current thermodynamic equilibrium models to predict aerosol NO3−
Authors: Yu Shaocai , Dennis Robin , Roselle Shawn , Nenes Athanasios , Walker John , Eder Brian , Schere Kenneth , Swall Jenise , Robarge Wayne
Published: February 2005

The partitioning of total nitrate (TNO3) and total ammonium (TNH4) between gas and aerosol phases is studied with two thermodynamic equilibrium models, ISORROPIA and the aerosol inorganics model (AIM), and three data sets: high time resolution measurement data from the 1999 Atlanta Supersite Experiment (summer case) and the 2002 Pittsburgh Air Quality Study (PAQS) Supersite Experiment (winter case), and 12‐hour measurement data from the Clinton site, North Carolina, in 1999. At the Atlanta site, both models reproduced a large percentage of the observed aerosol NH4+ and HNO3 (NH4+: >94% and HNO3: >86%) within a factor of 1.5, whereas neither model reproduced a majority of observed aerosol NO3− and NH3 (NO3−: <48% and NH3: <51%) within a factor of 2. At the Pittsburgh site, both models reproduced more than 76% of observed NO3− within a factor of 2. At the Clinton site, both models performed a little better on aerosol NO3− (47–58% within a factor of 1.5) than at the Atlanta site but worse than at the Pittsburgh site. Sensitivity test of thermodynamic models with Gaussian random errors indicates that in many cases, measurement errors in SO42− and TNH4 can explain a major fraction of the discrepancies between the equilibrium model predictions and observations in partitioning of TNO3. Comparison of predictions of the three‐dimensional (3‐D) Community Multiscale Air Quality (CMAQ) model with the observations over the continental United States indicates that the performance of the 3‐D model for NO3−, HNO3, NH4+, and NH3 strongly depends on its performance for TNO3, TNH4, and SO42−. Tests show that errors associated with SO42− and TNH4 predictions of the 3‐D model can result in the thermodynamic model calculation replicating only 47% and 60% of base case NO3− within a factor of 2 for summer and winter cases, respectively. It was found that errors in TNH4 are more critical than errors in SO42− to prediction of NO3−.
Initial Oligemia with Capillary Flow Stop Followed by Hyperemia during K+-Induced Cortical Spreading Depression in Rats
Authors: Tomita Minoru , Schiszler Istvan , Tomita Yutaka , Tanahashi Norio , Takeda Hidetaka , Osada Takashi , Suzuki Norihiro
Published: February 2005

Local cerebral blood volume (CBV) and capillary flow changes in regions of depolarizing neurons during K+-induced cortical spreading depression (CSD) in the cerebral cortex of α-chloralose-urethane-anesthetized rats were examined employing a transillumination (550 nm) video system. Capillary flow was calculated as the reciprocal of mean transit times of blood in pixels of 40 μm × 40 μm, each of which contains a few capillaries. Potassium microinjection into the cortex evoked repetitive wave-ring spreads of oligemia at a speed of ca. 2.33±0.48 mm/min. During the spread of CSD, tracer (either saline or carbon black) was injected into the internal carotid artery. Colocated with the oligemic wave, we detected capillary flow stop as evidenced by disappearance of the hemodilution curves. At any location in the region of interest within the cerebral cortex, we observed cyclic changes of capillary flow stop/hyperperfusion in synchrony with oligemia/hyperemia fluctuations. The initial flow stop and oligemia were ascribed to capillary compression by astroglial cell swelling, presumably at the pericapillary endfeet, since the oligemia occurred before larger vessel changes. We conclude that local depolarizing neurons can decrease adjacent capillary flow directly and immediately, most likely via astroglial cell swelling, and that the flow stop triggers upstream arteriolar dilatation for capillary hyperperfusion.
PET Studies of Net Blood—Brain Clearance of FDOPA to Human Brain: Age-Dependent Decline of [18F]Fluorodopamine Storage Capacity
Authors: Kumakura Yoshitaka , Vernaleken Ingo , Gründer Gerhard , Bartenstein Peter , Gjedde Albert , Cumming Paul
Published: February 2005

Conventional methods for the graphical analysis of 6-[18F]fluorodopa (FDOPA)/positron emission tomography (PET) recordings ( Kappin) may be prone to negative bias because of oversubtraction of the precursor pool in the region of interest, and because of diffusion of decarboxylated FDOPA metabolites from the brain. These effects may reduce the sensitivity of FDOPA/PET for the detection of age-related changes in dopamine innervations. To test for these biasing effects, we have used a constrained compartmental analysis to calculate the brain concentrations of the plasma metabolite 3- O-methyl-FDOPA (OMFD) during 120 mins of FDOPA circulation in healthy young, healthy elderly, and Parkinson's disease subjects. Calculated brain OMFD concentrations were subtracted frame-by-frame from the dynamic PET recordings, and maps of the FDOPA net influx to brain were calculated assuming irreversible trapping ( Kapp). Comparison of Kappin and Kapp maps revealed a global negative bias in the conventional estimates of FDOPA clearance. The present OMFD subtraction method revealed curvature in plots of Kapp at early times, making possible the calculation of the corrected net influx ( K) and also the rate constant for diffusion of decarboxylated metabolites from the brain ( kloss). The effective distribution volume (EDV2; K/ kloss) for FDOPA, an index of dopamine storage capacity in brain, was reduced by 85% in putamen of patients with Parkinson's disease, and by 58% in the healthy elderly relative to the healthy young control subjects. Results of the present study support claims that storage capacity for dopamine in both caudate and putamen is more profoundly impaired in patients with Parkinson's disease than is the capacity for DOPA utilization, calculated by conventional FDOPA net influx plots. The present results furthermore constitute the first demonstration of an abnormality in the cerebral utilization of FDOPA in caudate and putamen as a function of normal aging, which we attribute to loss of vesicular storage capacity.
The structure, energetics, and nature of the chemical bonding of phenylthiol adsorbed on the Au(111) surface: Implications for density-functional calculations of molecular-electronic conduction
Authors: Bilić Ante , Reimers Jeffrey R. , Hush Noel S.
Published: February 2005

The adsorption of phenylthiol on the Au(111) surface is modeled using Perdew and Wang density-functional calculations. Both direct molecular physisorption and dissociative chemisorption via S–H bond cleavage are considered as well as dimerization to form disulfides. For the major observed product, the chemisorbed thiol, an extensive potential-energy surface is produced as a function of both the azimuthal orientation of the adsorbate and the linear translation of the adsorbate through the key fcc, hcp, bridge, and top binding sites. Key structures are characterized, the lowest-energy one being a broad minimum of tilted orientation ranging from the bridge structure halfway towards the fcc one. The vertically oriented threefold binding sites, often assumed to dominate molecular electronics measurements, are identified as transition states at low coverage but become favored in dense monolayers. A similar surface is also produced for chemisorption of phenylthiol on Ag(111); this displays significant qualitative differences, consistent with the qualitatively different observed structures for thiol chemisorption on Ag and Au. Full contours of the minimum potential energy as a function of sulfur translation over the crystal face are described, from which the barrier to diffusion is deduced to be 5.8kcalmol−1, indicating that the potential-energy surface has low corrugation. The calculated bond lengths, adsorbate charge and spin density, and the density of electronic states all indicate that, at all sulfur locations, the adsorbate can be regarded as a thiyl species that forms a net single covalent bond to the surface of strength 31kcalmol−1. No detectable thiolate character is predicted, however, contrary to experimental results for alkyl thiols that indicate up to 20%–30% thiolate involvement. This effect is attributed to the asymptotic-potential error of all modern density functionals that becomes manifest through a 3–4eV error in the lineup of the adsorbate and substrate bands. Significant implications are described for density-functional calculations of through-molecule electron transport in molecular electronics.
Synthesis and Properties of d-π Conjugated Poly(phenylene silane)s
Authors: Duan Xiaobang , Xu Xuanyan , Wang Hongbo , Lu Ping
Published: February 2005

Poly(phenylene silane)s were constructed by step-growth copolymerization between difunctional Grignard reagents and dichlorodimethylsilane in moderate yields. 1H NMR spectroscopy confirmed the structure of the desired copolymers. Gel permeation chromatography showed narrow molecular dispersibility and conceivable molecular weights. Based on thermogravimetric analysis and luminescence studies, the synthesized copolymers were found to act as potential emitters in organic light-emitting diode displays.
Development without germ cells: The role of the germ line in zebrafish sex differentiation
Authors: Slanchev Krasimir , Stebler Jürg , de la Cueva-Méndez Guillermo , Raz Erez
Published: February 2005

The progenitors of the gametes, the primordial germ cells (PGCs) are typically specified early in the development in positions, which are distinct from the gonad. These cells then migrate toward the gonad where they differentiate into sperms and eggs. Here, we study the role of the germ cells in somatic development and particularly the role of the germ line in the sex differentiation in zebrafish. To this end, we ablated the germ cells using two independent methods and followed the development of the experimental fish. First, PGCs were ablated by knocking down the function of
dead end
, a gene important for the survival of this lineage. Second, a method to eliminate the PGCs using the toxin–antitoxin components of the
parD
bacterial genetic system was used. Specifically, we expressed a bacterial toxin Kid preferentially in the PGCs and at the same time protected somatic cells by uniformly expressing the specific antidote Kis. Our results demonstrate an unexpected role for the germ line in promoting female development because PGC-ablated fish invariably developed as males.
Regulation of osteoblastogenesis and bone mass by Wnt10b
Authors: Bennett Christina N. , Longo Kenneth A. , Wright Wendy S. , Suva Larry J. , Lane Timothy F. , Hankenson Kurt D. , MacDougald Ormond A.
Published: February 2005

Wnts comprise a family of secreted signaling proteins that regulate diverse developmental processes. Activation of Wnt signaling by Wnt10b inhibits differentiation of preadipocytes and blocks adipose tissue development; however, the effect of Wnt10b on other mesenchymal lineages has not been defined. To explore the physiological role of Wnt signaling in bone development, we analyzed FABP4-Wnt10b mice, which express the Wnt10b transgene in marrow. Femurs from FABP4-Wnt10b mice have almost four times as much bone in the distal metaphyses and are mechanically stronger. These mice maintain elevated bone mass at least through 23 months of age. In addition, FABP4-Wnt10b mice are protected from the bone loss characteristic of estrogen deficiency. We used pharmacological and genetic approaches to demonstrate that canonical Wnt signaling stimulates osteoblastogenesis and inhibits adipogenesis of bipotential mesenchymal precursors. Wnt10b shifts cell fate toward the osteoblast lineage by induction of the osteoblastogenic transcription factors Runx2, Dlx5, and osterix and suppression of the adipogenic transcription factors C/EBPα and PPARγ. One mechanism whereby Wnt10b promotes osteoblastogenesis is suppression of PPARγ expression. Finally, Wnt10b-/- mice have decreased trabecular bone and serum osteocalcin, confirming that Wnt10b is an endogenous regulator of bone formation.
Molecular cloning of TRPC3a, an N-terminally extended, store-operated variant of the human C3 transient receptor potential channel
Authors: Yildirim Eda , Kawasaki Brian T. , Birnbaumer Lutz
Published: February 2005

AK032317 is the GenBank accession no. of a full-length RIKEN mouse cDNA. It encodes a putative variant of the C3-type TRPC (transient receptor potential channel) that differs from the previously cloned murine TRPC3 cDNA in that it has a 5′ extension stemming from inclusion of an additional exon (exon 0). The extended cDNA adds 62 aa to the sequence of the murine TRPC3. Here, we report the cloning of a cDNA encoding the human homologue of this extended TRPC3 having a highly homologous 73-aa N-terminal extension, referred to as hTRPC3a. A query of the GenBank genomic database predicts the existence of a similar gene product also in rats. Transient expression of the longer TRPC3a in human embryonic kidney (HEK) cells showed that it mediates Ca
2+
entry in response to stimulation of the Gq–phospholipase C β pathway, which is similar to that mediated by the shorter hTRPC3. However, after isolation of HEK cells expressing hTRPC3 in stable form, TRPC3a gave rise to Ca
2+
-entry channels that are not only activated by the Gq–phospholipase C β pathway (receptor-activated Ca entry) but also by thapsigargin triggered store depletion. In conjunction with findings from our and other laboratories that TRPC1, TRPC2, TRPC4, TRPC5, and TRPC7, can each mediate store-depletion-activated Ca
2+
entry in mammalian cells, our findings with hTRC3a support our previous proposal that TRPCs form capacitative Ca-entry channels.
Single-neuron responses and neuronal decisions in a vernier task
Authors: Zhang Ying , Reid R. Clay
Published: February 2005

Vernier acuity is a measure of the smallest horizontal offset between two vertical lines that can be behaviorally discriminated. To examine the link between the neuronal responses in a retinotopic mosaic and vernier acuity, we recorded the responses of single cells in cat lateral geniculate nucleus to a vertical bar stimulus that was stepped in small increments through the receptive fields of cells. Based on the single-trial responses evoked by stimuli at different positions, we calculated the spatial resolution that could be achieved. If the stimulus could fall anywhere in their receptive fields, single neurons had spatial resolutions two times worse than previously reported vernier thresholds. Given the known coverage factor in a cat retina, we developed a two-stage decision model to examine how the responses of neurons in a retinotopic mosaic could be processed to achieve vernier acuity. In order for psychophysical thresholds to be accounted for by the responses of a single cell, the stimulus must fall in the quarter of the receptive field that provides the most information about stimulus position. Alternatively, both the absolute psychophysical threshold for vernier acuity and its dependence on stimulus length can be realized by pooling the responses of a few neurons, all located on one side of the bar stimulus.
Demonstration of toxicity to fish and to mammalian cells by
Pfiesteria
species: Comparison of assay methods and strains
Authors: Burkholder JoAnn M. , Gordon Andrew S. , Moeller Peter D. , Law J. Mac , Coyne Kathryn J. , Lewitus Alan J. , Ramsdell John S. , Marshall Harold G. , Deamer Nora J. , Cary S. Craig , Kempton Jason W. , Morton Steven L. , Rublee Parke A.
Published: February 2005

Toxicity and its detection in the dinoflagellate fish predators
Pfiesteria piscicida
and
Pfiesteria shumwayae
depend on the strain and the use of reliable assays. Two assays, standardized fish bioassays (SFBs) with juvenile fish and fish microassays (FMAs) with larval fish, were compared for their utility to detect toxic
Pfiesteria
. The comparison included strains with confirmed toxicity, negative controls (noninducible
Pfiesteria
strains and a related nontoxic cryptoperidiniopsoid dinoflagellate), and
P. shumwayae
strain CCMP2089, which previously had been reported as nontoxic. SFBs, standardized by using toxic
Pfiesteria
(coupled with tests confirming
Pfiesteria
toxin) and conditions conducive to toxicity expression, reliably detected actively toxic
Pfiesteria
, but FMAs did not.
Pfiesteria
toxin was found in fish- and algae-fed clonal
Pfiesteria
cultures, including CCMP2089, but not in controls. In contrast, noninducible
Pfiesteria
and cryptoperidiniopsoids caused no juvenile fish mortality in SFBs even at high densities, and low larval fish mortality by physical attack in FMAs. Filtrate from toxic strains of
Pfiesteria
spp. in bacteria-free media was cytotoxic. Toxicity was enhanced by bacteria and other prey, especially live fish. Purified
Pfiesteria
toxin extract adversely affected mammalian cells as well as fish, and it caused fish death at environmentally relevant cell densities. These data show the importance of testing multiple strains when assessing the potential for toxicity at the genus or species level, using appropriate culturing techniques and assays.
Fast, long-range, reversible conformational fluctuations in nucleosomes revealed by single-pair fluorescence resonance energy transfer
Authors: Tomschik Miroslav , Zheng Haocheng , van Holde Ken , Zlatanova Jordanka , Leuba Sanford H.
Published: February 2005

The nucleosome core particle, the basic repeated structure in chromatin fibers, consists of an octamer of eight core histone molecules, organized as dimers (H2A/H2B) and tetramers [(H3/H4)
2
] around which DNA wraps tightly in almost two left-handed turns. The nucleosome has to undergo certain conformational changes to allow processes that need access to the DNA template to occur. By single-pair fluorescence resonance energy transfer, we demonstrate fast, long-range, reversible conformational fluctuations in nucleosomes between two states: fully folded (closed), with the DNA wrapped around the histone core, or open, with the DNA significantly unraveled from the histone octamer. The brief excursions into an extended open state may create windows of opportunity for protein factors involved in DNA transactions to bind to or translocate along the DNA.
Expression of an additional cathelicidin antimicrobial peptide protects against bacterial skin infection
Authors: Lee Phillip H. A. , Ohtake Takaaki , Zaiou Mohamed , Murakami Masamoto , Rudisill Jennifer A. , Lin Kenneth H. , Gallo Richard L.
Published: February 2005

Cathelicidin antimicrobial peptides are effectors of innate immune defense in mammals. Humans and mice have only one cathelicidin gene, whereas domesticated mammals such as the pig, cow, and horse have multiple cathelicidin genes. We hypothesized that the evolution of multiple cathelicidin genes provides these animals with enhanced resistance to infection. To test this, we investigated the effects of the addition of cathelicidins by combining synthetic cathelicidin peptides
in vitro
, by producing human keratinocytes that overexpress cathelicidins in culture, or by producing transgenic mice that constitutively overexpress cathelicidins
in vivo
. The porcine cathelicidin peptide PR-39 acted additively with human cathelicidin LL-37 to kill group A
Streptococcus
(GAS). Lentiviral delivery of PR-39 enhanced killing of GAS by human keratinocytes. Finally, transgenic mice expressing PR-39 under the influence of a K14 promoter showed increased resistance to GAS skin infection (50% smaller necrotic ulcers and 60% fewer surviving bacteria). Similarly constructed transgenic mice designed to overexpress their native cathelicidin did not show increased resistance. These findings demonstrate that targeted gene transfer of a xenobiotic cathelicidin confers resistance against infection and suggests the benefit of duplication and divergence in the evolution of antimicrobial peptides.
Synthetic analogues of migrastatin that inhibit mammary tumor metastasis in mice
Authors: Shan Dandan , Chen Lin , Njardarson Jon T. , Gaul Christoph , Ma Xiaojing , Danishefsky Samuel J. , Huang Xin-Yun
Published: February 2005

Tumor metastasis is the most common cause of death in cancer patients. Here, we show that two, fully synthetic migrastatin analogues, core macroketone and core macrolactam, are potent inhibitors of metastasis in a murine breast tumor model. Administration of these readily accessible compounds nearly completely inhibits lung metastasis of highly metastatic mammary carcinoma cells. Treatment of tumor cells with core macroketone and core macrolactam blocks Rac activation, lamellipodia formation, and cell migration, suggesting that these chemical compounds interfere with the invasion step of the metastatic process. These compounds also inhibit the migration of human metastatic breast cancer cells, prostate cancer cells, and colon cancer cells but not normal mammary-gland epithelial cells, fibroblasts, and leukocytes. These data demonstrate that the macroketone and macrolactam core structures are specific small-molecule inhibitors of tumor metastasis. These compounds or their analogues could potentially be used in cancer-therapy strategies.
Identification of Functionally Interacting SNAREs by Using Complementary Substitutions in the Conserved `0' Layer
Authors: Graf Carmen T. , Riedel Dietmar , Schmitt Hans Dieter , Jahn Reinhard
Published: February 2005

Soluble N-ethylmaleimide–sensitive factor attachment protein receptor (SNARE) complexes form bundles of four parallel α-helices. The central `0' layer of interacting amino acid side chains is highly conserved and contains one arginine and three glutamines, leading to the classification of SNAREs into R, Qa, Qb, and Qc-SNAREs. Replacing one of the glutamines with arginine in the yeast exocytotic SNARE complex is either lethal or causes a conditional growth defect that is compensated by replacing the R-SNARE arginine with glutamine. Using the yeast SNARE complex mediating traffic from the endoplasmic reticulum to the Golgi apparatus, we now show that functionally interacting SNAREs can be mapped by systematically exchanging glutamines and arginines in the `0' layer. The Q→ R replacement in the Qb-SNARE Bos1p has the strongest effect and can be alleviated by an Q→ R replacement in the R-SNARE Sec22p. Four Q residues in the central layer caused growth defects above 30°C that were rescued by Q→ R substitutions in the Qa and Qc SNAREs Sed5p and Bet1p, respectively. The sec22(Q)/sed5(R) mutant is temperature sensitive and is rescued by a compensating R→ Q replacement in the R-SNARE Ykt6p. This rescue is attributed to the involvement of Sed5p and Ykt6p in a different SNARE complex that functions in intra-Golgi trafficking.
ADictyosteliumHomologue of WASP Is Required for Polarized F-Actin Assembly during Chemotaxis
Authors: Myers Scott A. , Han Ji W. , Lee Yoonsung , Firtel Richard A. , Chung Chang Y.
Published: February 2005

The actin cytoskeleton controls the overall structure of cells and is highly polarized in chemotaxing cells, with F-actin assembled predominantly in the anterior leading edge and to a lesser degree in the cell's posterior. Wiskott-Aldrich syndrome protein (WASP) has emerged as a central player in controlling actin polymerization. We have investigated WASP function and its regulation in chemotaxing Dictyostelium cells and demonstrated the specific and essential role of WASP in organizing polarized F-actin assembly in chemotaxing cells. Cells expressing very low levels of WASP show reduced F-actin levels and significant defects in polarized F-actin assembly, resulting in an inability to establish axial polarity during chemotaxis. GFP-WASP preferentially localizes at the leading edge and uropod of chemotaxing cells and the B domain of WASP is required for the localization of WASP. We demonstrated that the B domain binds to PI(4,5)P2and PI(3,4,5)P3with similar affinities. The interaction between the B domain and PI(3,4,5)P3plays an important role for the localization of WASP to the leading edge in chemotaxing cells. Our results suggest that the spatial and temporal control of WASP localization and activation is essential for the regulation of directional motility.
A Comparison of Electrodiagnostic Tests in Ocular Myasthenia Gravis
Authors: Katzberg Hans D , Bril Vera
Published: February 2005

Objectives:

We aimed to determine whether the diagnostic yield of single-fiber electromyography (SFEMG) in different grades of ocular myasthenia gravis (OMG) is enhanced by repetitive nerve stimulation studies (RNS).

Methods:

One hundred twenty-one patients with a diagnosis of mild, moderate, or severe OMG based on clinical criteria had SFEMG of the frontalis muscle and RNS of the facial nerve. Tests results were compared by contingency table analysis.

Results:

In these patients, 19% had abnormal RNS and 95% had abnormal SFEMG. SFEMG was abnormal in 93%, 96%, and 100% with mild, moderate, and severe OMG, respectively. One patient with abnormal RNS had normal SFEMG, but the SFEMG study was incomplete.

Conclusion:

Like in generalized MG, SFEMG is more sensitive than RNS for all grades of OMG. Furthermore, if a complete SFEMG study is normal, addition of RNS does not improve the diagnostic yield.
Evidence for Increased Apoptosis of Duodenal Intraepithelial Lymphocytes in Cow's Milk Sensitive Enteropathy
Authors: Augustin Merja T , Kokkonen Jorma , Karttunen Tuomo J
Published: February 2005

Objectives:

Enterocyte apoptosis induced by activated intraepithelial lymphocytes (IELs) is increased in celiac disease (CD). A lesser increment in intraepithelial lymphocytes associated with normal villous structure is also characteristic of cow's milk sensitive enteropathy (CMSE), but no information is available about the apoptosis rate of this condition.

Methods:

Endoscopic biopsy samples of 21 children with untreated CMSE were compared with samples from 15 children with CD and 18 controls. Apoptosis was analyzed using the TUNEL technique and the M30 antibody from duodenal bulb and mid‐duodenum samples. Ki‐67 was used to detect the proliferation rate and CD3 to count the overall number of T lymphocytes.

Results:

In the mid‐duodenum, CMSE patients showed a significantly increased intraepithelial and lamina propria density of TUNEL+ cells, but no difference in the density of M30+ epithelial cells was seen compared with controls. In CD subjects, TUNEL+ counts in mid‐duodenal villous epithelium were increased. CD3+ intraepithelial lymphocytes were increased in both CMSE and CD and correlated with TUNEL+ and M30+ counts among all patients. No increase in proliferation rate was seen in CMSE, and no significant correlations between apoptosis and proliferation rates were detected.

Conclusions:

The observed increase in TUNEL+ counts and the absence of any increase in M30+ cells suggest that the apoptosis rate of intraepithelial lymphocytes, but not of enterocytes, is increased in the small IELs in CMSE. However, the number of intraepithelial lymphocytes is still elevated in CMSE, indicating that a disturbance of homeostasis of intraepithelial lymphocytes is important in its pathogenesis.
Growth Assessment in Infants and Toddlers Using Three Different Reference Charts
Authors: Nash Andrea , Corey Mary , Sherwood Kelly , Secker Donna , Saab Joanne , O'Connor Deborah L
Published: February 2005

Objective:

To determine if the proportion of children ≤24 months old in a tertiary care facility defined as at risk of undernutrition or overnutrition differs according to different references used for assessment: the Centers for Disease Control and Prevention (CDC), National Center for Health Statistics (NCHS) or Tanner‐Whitehouse (Tanner) growth charts for weight‐for‐age and length‐for‐age.

Methods:

Lengths and weights were measured on infants (207 female, 341 male) aged ≤24 months admitted from or attending clinics in the General Pediatric or Respiratory Medicine Programs at The Hospital for Sick Children, Toronto. Weight‐for‐age and length‐for‐age percentiles and percent ideal body weight were electronically computed.

Results:

The proportion of all children whose weight‐for‐age was <3rd percentile (at risk of undernutrition) was greatest using the CDC growth charts (22.5%) compared with the NCHS (15.9%) or Tanner (19.2%) growth charts. Likewise, the proportion of all infants/toddlers with percent ideal body weight <90 (at risk of undernutrition) was greatest using the CDC (32.3%) compared with the NCHS (22.1%) or Tanner (25.9%) growth charts. In contrast, the percentage of children whose percent ideal body weight was ≥110% (at risk of overnutrition) was least using the CDC (18.1%) compared with the NCHS (26.1%) or Tanner (22.4%) growth charts.

Conclusion:

More children aged ≤24 months will be defined as at risk of undernutrition and fewer at risk of overnutrition when using weight‐for‐age or percent ideal body weight and the CDC growth charts compared with the NCHS or Tanner growth charts. As a result, requests for a more detailed nutritional assessment for undernutrition will likely follow implementation of the CDC growth charts in a tertiary care setting. As the CDC, NCHS and Tanner growth charts are growth “references” rather than “standards,” other than for screening purposes, they should not be used in isolation when assessing growth and nutritional status.
Water Deficits Affect Caffeate O-Methyltransferase, Lignification, and Related Enzymes in Maize Leaves. A Proteomic Investigation
Authors: Vincent Delphine , Lapierre Catherine , Pollet Brigitte , Cornic Gabriel , Negroni Luc , Zivy Michel
Published: February 2005

Drought is a major abiotic stress affecting all levels of plant organization and, in particular, leaf elongation. Several experiments were designed to study the effect of water deficits on maize (Zea mays) leaves at the protein level by taking into account the reduction of leaf elongation. Proteomic analyses of growing maize leaves allowed us to show that two isoforms of caffeic acid/5-hydroxyferulic 3-O-methyltransferase (COMT) accumulated mostly at 10 to 20 cm from the leaf point of insertion and that drought resulted in a shift of this region of maximal accumulation toward basal regions. We showed that this shift was due to the combined effect of reductions in growth and in total amounts of COMT. Several other enzymes involved in lignin and/or flavonoid synthesis (caffeoyl-CoA 3-O-methyltransferase, phenylalanine ammonia lyase, methylenetetrahydrofolate reductase, and several isoforms of S-adenosyl-l-methionine synthase and methionine synthase) were highly correlated with COMT, reinforcing the hypothesis that the zone of maximal accumulation corresponds to a zone of lignification. According to the accumulation profiles of the enzymes, lignification increases in leaves of control plants when their growth decreases before reaching their final size. Lignin levels analyzed by thioacidolysis confirmed that lignin is synthesized in the region where we observed the maximal accumulation of these enzymes. Consistent with the levels of these enzymes, we found that the lignin level was lower in leaves of plants subjected to water deficit than in those of well-watered plants.
Monoterpene Metabolism. Cloning, Expression, and Characterization of Menthone Reductases from Peppermint
Authors: Davis Edward M. , Ringer Kerry L. , McConkey Marie E. , Croteau Rodney
Published: February 2005

(−)-Menthone is the predominant monoterpene produced in the essential oil of maturing peppermint (Mentha x piperita) leaves during the filling of epidermal oil glands. This early biosynthetic process is followed by a second, later oil maturation program (approximately coincident with flower initiation) in which the C3-carbonyl of menthone is reduced to yield (−)-(3R)-menthol and (+)-(3S)-neomenthol by two distinct NADPH-dependent ketoreductases. An activity-based in situ screen, by expression in Escherichia coli of 23 putative redox enzymes from an immature peppermint oil gland expressed sequence tag library, was used to isolate a cDNA encoding the latter menthone:(+)-(3S)-neomenthol reductase. Reverse transcription-PCR amplification and RACE were used to acquire the former menthone:(−)-(3R)-menthol reductase directly from mRNA isolated from the oil gland secretory cells of mature leaves. The deduced amino acid sequences of these two reductases share 73% identity, provide no apparent subcellular targeting information, and predict inclusion in the short-chain dehydrogenase/reductase family of enzymes. The menthone:(+)-(3S)-neomenthol reductase cDNA encodes a 35,722-D protein, and the recombinant enzyme yields 94% (+)-(3S)-neomenthol and 6% (−)-(3R)-menthol from (−)-menthone as substrate, and 86% (+)-(3S)-isomenthol and 14% (+)-(3R)-neoisomenthol from (+)-isomenthone as substrate, has a pH optimum of 9.3, and K  m values of 674 μ  m, > 1 mm, and 10 μ  m for menthone, isomenthone, and NADPH, respectively, with a k  cat of 0.06 s−1. The recombinant menthone:(−)-(3R)-menthol reductase has a deduced size of 34,070 D and converts (−)-menthone to 95% (−)-(3R)-menthol and 5% (+)-(3S)-neomenthol, and (+)-isomenthone to 87% (+)-(3R)-neoisomenthol and 13% (+)-(3S)-isomenthol, displays optimum activity at neutral pH, and has K  m values of 3.0 μ  m, 41 μ  m, and 0.12 μ  m for menthone, isomenthone, and NADPH, respectively, with a k  cat of 0.6 s−1. The respective activities of these menthone reductases account for all of the menthol isomers found in the essential oil of peppermint. Biotechnological exploitation of these genes could lead to improved production yields of (−)-menthol, the principal and characteristic flavor component of peppermint.
Ozone-Induced Programmed Cell Death in the Arabidopsis radical-induced cell death1 Mutant
Authors: Overmyer Kirk , Brosché Mikael , Pellinen Riikka , Kuittinen Tero , Tuominen Hannele , Ahlfors Reetta , Keinänen Markku , Saarma Mart , Scheel Dierk , Kangasjärvi Jaakko
Published: February 2005

Short, high-concentration peaks of the atmospheric pollutant ozone (O3) cause the formation of cell death lesions on the leaves of sensitive plants. Numerous similarities between the plant responses to O3 and pathogens suggest that O3 triggers hypersensitive response-like programmed cell death (PCD). We examined O3 and superoxide-induced cell death in the O3-sensitive radical-induced cell death1 (rcd1) mutant. Dying cells in O3-exposed rcd1 exhibited several of the typical morphological characteristics of the hypersensitive response and PCD. Double-mutant analyses indicated a requirement for salicylic acid and the function of the cyclic nucleotide-gated ion channel AtCNGC2 in cell death. Furthermore, a requirement for ATPases, kinases, transcription, Ca2+ flux, caspase-like proteolytic activity, and also one or more phenylmethylsulfonyl fluoride-sensitive protease activities was shown for the development of cell death lesions in rcd1. Furthermore, mitogen-activated protein kinases showed differential activation patterns in rcd1 and Columbia. Taken together, these results directly demonstrate the induction of PCD by O3.
Enterprise skills for the economy
Authors: Galloway Laura , Anderson Maggie , Brown Wendy , Wilson Laura
Published: February 2005

Purpose

In response to the emergence of an enterprise economy, government claims that building an enterprise culture is vital. Correspondingly, provision of entrepreneurship education in higher education has expanded. The paper aims to assess the potential of entrepreneurship education to develop skills, and of whether students perceive them as having value within the modern economy.

Design/methodology/approach

The paper draws from a longitudinal, collaborative study of students of entrepreneurship in four universities. Using a questionnaire‐based methodology, the paper is based on responses from a sample of 519 students.

Findings

Results include that any increase in graduate entrepreneurship is most likely to be a long‐term. Results also suggest that many students expect to work in new and small firms, and that skills developed by entrepreneurship education are applicable to both waged employment and entrepreneurship. Accordingly, entrepreneurship education seems to have much potential to develop skills appropriate for the enterprise economy.

Research limitations/implications

The research is limited by its quantitative nature. As the primary purpose is to evaluate attitudes to entrepreneurship and perceptions of the economic environment, further research should involve qualitative follow‐up, in the form of focus groups and/or longitudinal case studies.

Originality/value

The value of the paper lies in the suggestion that investment in entrepreneurship education is likely to have a positive impact within the economy. The long‐term impact of an increase in awareness of entrepreneurship; of the ability to start firms; and an increase in skills transferable to waged employment within an enterprise‐based economy, can not be underestimated.
Review of luminescent based fibre optic temperature sensors
Authors: McSherry M. , Fitzpatrick C. , Lewis E.
Published: February 2005

Purpose

There are various temperature measuring systems presented in the literature and on the market today. Over the past number of years a range of luminescent‐based optical fibre sensors have been reported and developed which include fluorescence and optical scattering. These temperature sensors incorporate materials that emit wavelength shifted light when excited by an optical source. The majority of commercially available systems are based on fluorescent properties.Design/methodology/approach– Many published journal articles and conference papers were investigated and existing temperature sensors in the market were examined.Findings– In optical thermometry, the light is used to carry temperature information. In many cases optical fibres are used to transmit and receive this light. Optical fibres are immune to electromagnetic interference and are small in size, which allows them to make very localized measurements. A temperature sensitive material forms a sensor and the subsequent optical data are transmitted via optical fibres to electronic detection systems. Two keys areas were investigated namely fluorescence based temperature sensors and temperature sensors involving optical scattering.Originality/value– An overview of optical fibre temperature sensors based on luminescence is presented. This review provides a summary of optical temperature sensors, old and new which exist in today's world of sensing.
Economics and religion
Authors: Alvey James E.
Published: February 2005

Purpose

In the Western world the voices calling for a secular society have grown ever louder over the last three centuries. This paper seeks to return to one of the founders of modernity for guidance. Adam Smith advocated globalization on economic and moral grounds.Design/methodology/approach– A discussion focusing on those calling for a secular society and, in addition to these normative advocates, various social scientists have propounded the “secularization thesis”; after analysing history from a purportedly positive view, they have argued that “modernization” leads to a secular society. Recently globalization has been seen as another cause of secularization. At the same time, the revival of various religions has cast doubt on these claims.Findings– Smith did not see secularization as an inevitable consequence of globalization. Further, despite his awareness of the arguments of the advocates of secular society (and contrary to some commentators like Minowitz), he rejected their advice. For him, a secular community was neither a necessary nor a desirable consequence of globalization.Originality/value– Provides a viewpoint on some of Adam Smith's thoughts and ideas.
Possibilities of affecting the chemical resistances of the coatings formed by reaction of amino resins with alkyd resins
Authors: Kalenda P. , Kalendová A.
Published: February 2005

The paper deals with the mode of film formation from urea–formaldehyde and melamine–formaldehyde resins combined with alkyd resin based on castor oil‐modified alkyd. The properties of hardened coatings (such as hardness, chemical stability, and adhesion to substrate) were followed in dependence on the ratios of reaction components. An apparatus was built for measuring the formaldehyde emissions escaping from the solid coating films. The determination was performed by the pararosaniline method. The addition of imidazolidine in a concentration up to 10 per cent can reduce the emissions of formaldehyde escaping from the solid films to a considerable amount.