bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficient production of active chicken avidin using a bacterial signal peptide in Escherichia coli
Authors: HYTÖNEN Vesa P. , LAITINEN Olli H. , AIRENNE Tomi T. , KIDRON Heidi , MELTOLA Niko J. , PORKKA Eevaleena J. , HÖRHÄ Jarno , PALDANIUS Tiina , MÄÄTTÄ Juha A. E. , NORDLUND Henri R. , JOHNSON Mark S. , SALMINEN Tiina A. , AIRENNE Kari J. , YLÄ-HERTTUALA Seppo , KULOMAA Markku S.
Published: November 2004

Chicken avidin is a highly popular tool with countless applications in the life sciences. In the present study, an efficient method for producing avidin protein in the periplasmic space of Escherichia coli in the active form is described. Avidin was produced by replacing the native signal sequence of the protein with a bacterial OmpA secretion signal. The yield after a single 2-iminobiotin–agarose affinity purification step was approx. 10 mg/l of virtually pure avidin. Purified avidin had 3.7 free biotin-binding sites per tetramer and showed the same biotin-binding affinity and thermal stability as egg-white avidin. Avidin crystallized under various conditions, which will enable X-ray crystallographic studies. Avidin produced in E. coli lacks the carbohydrate chains of chicken avidin and the absence of glycosylation should decrease the non-specific binding that avidin exhibits towards many materials [Rosebrough and Hartley (1996) J. Nucl. Med. 37, 1380–1384]. The present method provides a feasible and inexpensive alternative for the production of recombinant avidin, avidin mutants and avidin fusion proteins for novel avidin–biotin technology applications.
A novel UBA and UBX domain protein that binds polyubiquitin and VCP and is a substrate for SAPKs
Authors: McNEILL Helen , KNEBEL Axel , ARTHUR J. Simon C. , CUENDA Ana , COHEN Philip
Published: November 2004

A widely expressed protein containing UBA (ubiquitin-associated) and UBX (ubiquitin-like) domains was identified as a substrate of SAPKs (stress-activated protein kinases). Termed SAKS1 (SAPK substrate-1), it was phosphorylated efficiently at Ser200in vitro by SAPK3/p38γ, SAPK4/p38δ and JNK (c-Jun N-terminal kinase), but weakly by SAPK2a/p38α, SAPK2b/p38β2 or ERK (extracellular-signal-regulated kinase) 2. Ser200, situated immediately N-terminal to the UBX domain, became phosphorylated in HEK-293 (human embryonic kidney) cells in response to stressors. Phosphorylation was not prevented by SB 203580 (an inhibitor of SAPK2a/p38α and SAPK2b/p38β2) and/or PD 184352 (which inhibits the activation of ERK1 and ERK2), and was similar in fibroblasts lacking both SAPK3/p38γ and SAPK4/p38δ or JNK1 and JNK2. SAKS1 bound ubiquitin tetramers and VCP (valosin-containing protein) in vitro via the UBA and UBX domains respectively. The amount of VCP in cell extracts that bound to immobilized GST (glutathione S-transferase)–SAKS1 was enhanced by elevating the level of polyubiquitinated proteins, while SAKS1 and VCP in extracts were coimmunoprecipitated with an antibody raised against S5a, a component of the 19 S proteasomal subunit that binds polyubiquitinated proteins. PNGase (peptide N-glycanase) formed a 1:1 complex with VCP and, for this reason, also bound to immobilized GST–SAKS1. We suggest that SAKS1 may be an adaptor that directs VCP to polyubiquitinated proteins, and PNGase to misfolded glycoproteins, facilitating their destruction by the proteasome.
Intestinal candyfloss
Authors: BROCKHAUSEN Inka
Published: November 2004

In this issue of the Biochemical Journal, Robbe et al. have employed a state-of-the-art MS technique to re-examine the sweet and sticky sugar covering of human intestinal mucosa. The availability of highly sensitive MS methods has been instrumental in determining the complex structures of mucin oligosaccharides, and in demonstrating that there are variations in structure along the sections of the gut. In contrast to previous studies, these results described by Robbe et al. show some correlation with the activities of enzymes synthesizing mucin oligosaccharides in the human colon. Many questions still remain to be answered: for example, regarding the regulation of the relative amounts of sugar chains in individual mucins, and their roles in the homoeostasis of the intestinal mucosa. Structural studies are a solid basis for understanding the functions of sugar chains, and the mechanisms and significance of changes during the development of intestinal disease.
Rofecoxib decreases renal injury in obese Zucker rats
Authors: DEY Aparajita , MARIC Christine , KAESEMEYER Wayne H. , ZAHARIS Constantine Z. , STEWART Janet , POLLOCK Jennifer S. , IMIG John D.
Published: November 2004

The present study tested the hypothesis that altered vascular regulation of arachidonic acid enzymes in obese Zucker rats contributes to renal damage. Protein expression of CYP450 (cytochrome P450) and COX (cyclo-oxygenase) enzymes in renal microvessels was studied in obese and lean Zucker rats at 20–21 weeks of age. Body weight and blood glucose averaged 649±13 g and 142±10 mg/dl in obese Zucker rats compared with 437±10 g and 111±5 mg/dl in age-matched lean Zucker rats. Renal microvascular CYP4A and COX-2 protein levels were increased and CYP2C protein levels decreased in obese Zucker rats. TX (thromboxane) B2 excretion was 2-fold higher and PG (prostaglandin) E2 excretion significantly lower in obese Zucker rats. Additional studies investigated the ability of the COX-2 inhibitor, rofecoxib, to slow the progression of renal injury in obese Zucker rats. Rofecoxib treatment decreased urinary PGF2α and 8-isoprostane levels in obese Zucker rats. Renal microvessel mRNA expression of pro-inflammatory chemokines was decreased in COX-2-inhibitor-treated obese Zucker rats. Urinary albumin excretion, an index of kidney damage, averaged 95±11 mg/day in vehicle-treated and 9±1 mg/day in rofecoxib-treated obese Zucker rats. Glomerulosclerosis, characterized by mesangial expansion, tubulo-interstitial fibrosis and extracellular matrix accumulation, was prominent in obese Zucker rats compared with a lack of damage in age-matched lean Zucker rats and rofecoxib-treated obese Zucker rats. These results suggest that altered vascular arachidonic acid enzymes contribute to the renal damage, and that COX-2 inhibition decreases glomerular injury in obese Zucker rats.
Non-esterified fatty acids impair endothelium-dependent vasodilation in rat mesenteric resistance vessels
Authors: SAINSBURY Christopher A. R. , SATTAR Naveed , CONNELL John M. C. , HILLIER Chris , PETRIE John R.
Published: November 2004

Elevated circulating levels of NEFAs (non-esterified fatty acids) are associated with states of insulin resistance and increased risk of vascular disease. Previous animal and human studies have demonstrated NEFA-induced endothelial dysfunction of large conduit arteries, reversible by the antioxidant ascorbic acid. We therefore investigated the effect of NEFAs on carbachol-induced endothelium-dependent vasodilation of rat resistance arteries in vitro using the technique of wire myography. In addition, we investigated the effect of co-incubation of NEFAs and ascorbic acid. Cumulative concentration–response curves to carbachol (endothelium-dependent vasodilation) and SNAP (S-nitroso-N-acetyl-DL-penicillamine; endothelium-independent vasodilation) were constructed. Those to carbachol were repeated following a 30 min incubation with either oleic acid (10−4 M) or palmitic acid (10−4 M), demonstrating significant impairment of endothelium-dependent vasodilation with both [P<0.05, comparison of pD2 values (the negative log concentration of agonist required to effect a 50% response)]. A cumulative concentration–response curve to carbachol was repeated following co-incubation with palmitic acid (10−4 M) and the antioxidant ascorbic acid (10−5 M), demonstrating an abolition of the previously observed endothelial dysfunction induced by palmitic acid. There was no impairment of vasodilation to SNAP following NEFA incubation. We conclude that NEFAs directly impair endothelial function in rat resistance arteries via an increase in oxidative stress at the vascular endothelium.
Enhancement of luminescent properties of ZnS:Mn nanophosphors by controlled ZnO capping
Authors: Karar N. , Chander Harish , Shivaprasad S. M.
Published: November 2004

Results of a method is presented for synthesizing ZnS:Mn nanoparticles capped in situ by ZnO. Analysis of Raman spectra and x-ray photoelectron spectra results have reinforced claim of the formation of ZnO capping layer on the surface of ZnS:Mn nanoparticles. Raman spectra results also showed presence of stress at an optimum ZnO capping thickness. In brief, the only variation within samples is in their ZnO capping thickness. Phase formation was analyzed and confirmed from powder x-ray diffraction. ZnS:Mn particle size is about 4nm. The change in photoluminescent properties with ZnO capping thickness variation is presented. It is shown that the variation in ZnO thickness and the resultant stress leads to an enhanced photoluminescence intensity/efficiency of nano-ZnS:Mn.
Supercontinuum growth in a highly nonlinear fiber with a low-coherence semiconductor laser diode
Authors: Abeeluck A. K. , Headley C.
Published: November 2004

A low-coherence, amplified, cw semiconductor laser diode is used as a pump to demonstrate supercontinuum (SC) generation in a highly nonlinear, dispersion-shifted fiber (HNLF). At a launch power of 1.6W into the anomalous-dispersion regime of 5km of HNLF, a SC extending from 1230nm to greater than 1770nm is achieved. The SC grows through the seeding effect of modulation instability that also converts the cw beam into short pulses so that subsequent spectral broadening becomes similar to pumping with pulsed laser sources. The experimental data show the manifestation of soliton self-frequency shift associated with a Stokes band as the launch power is increased. Amplification of the continuum noise with respect to the cw pump is also reported.
Nanocavity in a silicon waveguide for ultrasensitive nanoparticle detection
Authors: Schmidt Bradley , Almeida Vilson , Manolatou Christina , Preble Stefan , Lipson Michal
Published: November 2004

We demonstrate the use of a micron-size planar silicon photonic device for the detection of ultralow concentrations of metal nanoparticles. The high detection sensitivity is achieved by using a strong light confining structure that enhances the effective extinction cross section of metal nanoparticles. We demonstrate the detection of 10nm diameter gold particles with a density of fewer than 1.25 particles per 0.04μm2. Using such a device one could detect the presence of single metal nanoparticles specifically bound to various analytes, enabling ultrasensitive detection of analytes including DNA, RNA, proteins, and antigens.
Effective masses and complex dielectric function of cubic HfO2
Authors: Garcia J. C. , Scolfaro L. M. R. , Leite J. R. , Lino A. T. , Freire V. N. , Farias G. A. , da Silva E. F.
Published: November 2004

The electronic band structure of cubic HfO2 is calculated using an ab initio all-electron self-consistent linear augmented plane-wave method, within the framework of the local-density approximation and taking into account full-relativistic contributions. From the band structure, the carrier effective masses and the complex dielectric function are obtained. The Γ-isotropic heavy and light electron effective masses are shown to be several times heavier than the electron tunneling effective mass measured recently. The imaginary part of the complex dielectric function ϵ2(ω) is in good agreement with experimental data from ultraviolet spectroscopic ellipsometry measurements in bulk yttria-stabilized HfO2 as well as with those performed in films deposited with the tetrakis diethylamido hafnium precursor for energies smaller than 9.5eV.
First-principles calculations of the mean inner Coulomb potential for sphalerite type II–VI semiconductors
Authors: Schowalter M. , Lamoen D. , Rosenauer A. , Kruse P. , Gerthsen D.
Published: November 2004

The mean inner Coulomb potential (MIP) of ZnS, CdS, ZnSe, CdSe, ZnTe, and CdTe has been calculated for a (110) slab geometry by the full potential linearized augmented plane-wave (FLAPW) method using both the local density approximation (LDA) and a generalized gradient approximation (GGA) for the exchange and correlation part of the potential. Typical differences between values calculated within the LDA and the GGA are smaller than typical experimental error bars in literature. We use experimental and self-consistently calculated lattice parameters for the calculation of the MIP. Values calculated for ZnS are compared with experimental values.
Localized surface plasmon singularities in amplifying media
Authors: Lawandy N. M.
Published: November 2004

The localized surface plasmon resonance of nanostructures is shown to exhibit a singularity when the surrounding medium exhibits amplification with a critical value of gain. This singularity can lead to large enhancements even when the gain is saturated. This composite medium should exhibit strong scattering within the plasmon band leading to low threshold random laser action and light localization effects. This effect could also greatly increase surface enhanced Raman scattering signals for rapid single, molecule detection, identification and sequencing.
Infrared photocurrent spectral response from plastic solar cell with low-band-gap polyfluorene and fullerene derivative
Authors: Wang Xiangjun , Perzon Erik , Delgado Juan Luis , de la Cruz Pilar , Zhang Fengling , Langa Fernando , Andersson Mats , Inganäs Olle
Published: November 2004

Plastic solar cells were fabricated using a low-band-gap alternating copolymer of fluorene and a donor–acceptor–donor moiety (APFO-Green1), blended with [6,6]-phenyl-C61-butyric acid methylester or 3′-(3,5-Bis-trifluoromethylphenyl)-1′-(4-nitrophenyl)pyrazolino[60]fullerene as electron acceptors. The polymer shows optical absorption in two wavelength ranges from 300<λ<500nm and 650<λ<1000nm. Devices based on APFO-Green1 blended with the later fullerene exhibit an outstanding photovoltaic behavior at the infrared range, where the external quantum efficiency is as high as 8.4% at 840nm and 7% at 900nm, while the onset of photogeneration is found at 1μm. A photocurrent density of 1.76mA∕cm2, open-circuit voltage of 0.54V, and power conversion efficiency of 0.3% are achieved under the illumination of AM1.5 (1000W∕m2) from a solar simulator.
Dual role of fluorine at the Si–SiO2 interface
Authors: Tsetseris L. , Zhou X. J. , Fleetwood D. M. , Schrimpf R. D. , Pantelides S. T.
Published: November 2004

Fluorine is known to have both a beneficial and adverse role on the characteristics of Si–SiO2-based devices. Here we report the results of first-principles calculations in terms of which we elucidate this dual behavior. On one hand, we find that Si–F interfacial bonds are resistant to depassivation by hydrogen species, with the process being shut down in the presence of holes. However, we also show that any excess of fluorine has a negative effect since it either creates stretched bonds, which can act as carrier traps, or disrupts an abrupt interface by cleavage of Si–Si bonds.
Electrical tunable Fabry–Perot interferometer using a poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) terpolymer
Authors: Jeong Dae-Yong , Ye Yong-Hong , Zhang Q. M.
Published: November 2004

Electrical tunable Fabry-Perot interferometers (FPIs) using a poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) terpolymer were fabricated and characterized. Using pure strain tuning, which for the terpolymer films under mechanically clamped condition is 1.3% under 100 V/μm field, we show that a tunable range of 22.5 nm can be obtained at wavelengths near 1.5 μm. Due to the opposite sign of the field-induced strain and the refractive index change from the electro-optic effect, the FPI using a terpolymer film directly as the cavity of the etalon shows a smaller tunability (0.78% under 100 V/μm).
Fabrication of metal–oxide–semiconductor field-effect transistors using crystalline γ-Al2O3 films as the gate dielectrics
Authors: Okada Takayuki , Sawada Kazuaki , Ishida Makoto , Shahjahan Mohammad
Published: November 2004

Crystalline γ-Al2O3 films were employed as high-κ gate dielectrics in metal–oxide–semiconductor field-effect transistors (MOSFETs) and characterization of these devices was performed. The crystalline dielectric was deposited with thicknesses of 4.0–4.5nm by mixed source molecular beam epitaxy and the capacitance equivalent thicknesses obtained were 2.7–2.9nm. The MOSFETs had exceptionally steep subthreshold slopes (63–67mV∕decade), relatively low negative fixed charge densities (5–7×1012cm−2) and interface state densities (2–3×1011eV−1cm−2). The maximum values of the effective carrier mobilities were 145cm2∕Vs for electrons and 85cm2∕Vs for holes.
Anomalous energetics and defect-assisted diffusion of Ga in silicon
Authors: Melis Claudio , Lopez Giorgia M. , Fiorentini Vincenzo
Published: November 2004

We study via first-principles calculations the energetics and diffusion of Ga in c-Si. In contrast to B and In, the favored Ga/self-interstitial complex is the tetrahedral interstitial GaT. Thus in the presence of self-interstitials Ga becomes interstitial, and is electrically deactivated as an acceptor. Studying the native-defect assisted diffusion, we find a self-interstitial-assisted mechanism to be favored; vacancy-assisted diffusion has a sizably larger activation energy, in agreement with the observed transient enhanced diffusion behavior.
Phase locking in a fiber laser array with varying path lengths
Authors: Liu Liping , Zhou Yi , Kong Fanting , Chen Y. C. , Lee Kotik K.
Published: November 2004

Phase locking has been demonstrated in fiber lasers coupled to a common resonator containing a spatial filter. The phase-locked mode is highly stable despite the phase variations in the individual elements caused by thermal and mechanical effects. The ability to maintain phase locking is attributed to a self-adjusting process, which can be found only in systems with a combination of high gain, long length, low Q, and broad gain bandwidth, all of which can be met in fiber laser arrays.
Delay effect of switch-on in a supertwisted nematic cell
Authors: Yang Fuzi , Dong Youmei , Ruan L. Z. , Sambles J. R.
Published: November 2004

By using a convergent beam system and the fully leaky guided mode technique the switch-on dynamics of an 180° supertwisted nematic have been studied. Using the Ericksen–Leslie theory and analyzing the guided mode data taken from the cell, the director structure in the cell at different times during switch-on is obtained. For three different applied voltages it is found that the switch-on time is strongly dependent on the applied field—the higher voltage corresponds to faster switching, with no evidence of backflow. A delay at the beginning of the switch-on process has been found and explored for different applied fields. This leads to a suggestion for increasing the switch-on speed of such devices by 25%.
Evidence of Si∕SiGe heterojunction roughness scattering
Authors: Liu C. W. , Lee M. H. , Lee Y. C. , Chen P. S. , Yu C.-Y. , Wei J.-Y. , Maikap S.
Published: November 2004

The separation distance between the electron channel at oxide∕Si interface and the strained-Si∕relaxed-SiGe heterojunction can significantly affect the effective electron mobility of metal–oxide–silicon field-effect transistors due to the roughness scattering of the underneath Si∕SiGe heterojunction. The mobility degradation due to the Si∕SiGe heterojunction with the roughness of 7 nm becomes insignificant when the strained-Si thickness is larger than ∼20nm. A clear hole confinement shoulder is observed in the accumulation region of the capacitance–voltage curves, indicating that the abrupt transition from the SiGe buffer to strained Si is maintained at the rough heterojunction. The heterojunction roughness scattering not only degrades the electron mobility, but also degrades the device characteristics such as the transconductance and cut-off frequency.
Tunable magnetization damping in transition metal ternary alloys
Authors: Ingvarsson S. , Xiao Gang , Parkin S. S. P. , Koch R. H.
Published: November 2004

We show that magnetization damping in Permalloy, Ni80Fe20, can be enhanced sufficiently to reduce postswitching magnetization precession to an acceptable level by alloying with the transition metal Os (osmium). The damping increases monotonically upon raising the Os concentration in Permalloy, at least up to 9% of Os. Other effects of alloying with Os are suppression of magnetization and enhancement of in-plane anisotropy. Magnetization damping also increases significantly upon alloying with the five other transition metals included in this study (4d elements: Nb, Ru, Rh; 5d elements: Ta, Pt) but never as strongly as with Os.
A descriptive study of stress fractures in competitive event horses in the UK
Authors: Hayton Emma , Sneddon Jennifer C
Published: November 2004

The impact of stress fractures on competitive event horses in the UK is completely unknown. Ninety-one replies to 450 questionnaires sent to competitive event riders across the UK indicated that 11 horses, representing 12% of the responders, had a confirmed stress fracture. As data on the total number of horses owned or ridden by the riders were not available, the true prevalence of stress fractures in this sample of horses could not be directly assessed. Within the bounds of this study, competitive level of the rider had a significant effect on stress fracture prevalence (X2(0.05, df. 2) = 24.74, P<0.05), as did years of eventing experience (X2(0.05, df. 1) = 27.80, P<0.01). Training regime was also influential (X2(0.05,df. 1) = 26.30, PX20.01). There was a predominance of fractures in geldings (X2(0.05, df. 1) = 24.45, P<0.03); however, geldings constituted 82% of reported cases. Thoroughbred cross horses had a significantly lower incidence of stress fractures than Thoroughbreds (X2(0.05, df. 1) = 20.82, P<0.01) but constituted only 18% of the sample. Horses in the oldest age category (9–12 years) had 6% of all stress fractures (X2(0.05, df. 2) = 24.54, P<0.1). All fractures occurred on the foreleg at the knee or below, with no significant effect of anatomical location. Seventy-three per cent of horses were not competing when diagnosed (X2(0.05, df. 1) = 22.27, P<0.1). These data indicate that useful preliminary data were yielded by the questionnaire and that further research with a larger sample size is justified.
Genetic influence on East African running success
Authors: Scott Robert A , Moran Colin , Wilson Richard H , Goodwin Will H , Pitsiladis Yannis P
Published: November 2004

East African athletes now dominate international distance running events from the 800 m to the marathon. Explanations for their phenomenal success have included optimal environmental conditions for developing distance running performance, psychological advantage and advantageous physiological characteristics. It is well established that genetics plays a role in determining inter-individual differences in exercise performance and adaptation to training stimuli. It is not known, however, to what extent inter-population differences (i.e. between ‘races’ and/or ethnic groups) in exercise performance can be attributed to genetics. There have been considerations that ‘black’ athletes are genetically adapted towards performance, given the concurrent success of athletes of West African ancestry in sprint events. However, the current notion of ‘race’ is not universally accepted, and genetic differences within and between populations are not clearly delineated by geographical or ethnic categorizations. Recent findings from mitochondrial DNA show that the populations from which Ethiopian athletes are drawn have not been isolated populations and are not genetically distinct from other Ethiopians. Y-chromosome analysis of the same population shows concurrent results, although some differences are present between athletes and the general Ethiopian population, suggesting an influence of the Y chromosome on athlete status in Ethiopia. It is concluded that there may be a role for genetics in the success of East African athletes; however, any genetic component to their success is unlikely to be limited to East Africans and is more likely to be found in other populations. At present it is unjustified to implicate a role for genetics in the success of East African runners when no genes have been identified as being important to their performance.
Eight conjectures about exchange rates
Authors: Horne Jocelyn
Published: November 2004

This paper examines and dissects eight popular conjectures about exchange rates. The conjectures are: there exists a systematic linkage between economic fundamentals and exchange rates; flexible exchange rates are unstable due to destabilising speculation; flexible exchange rates are excessively volatile; the foreign exchange market is efficient; purchasing power parity holds; volatile exchange rates are harmful to trade; depreciating exchange rates trigger a “vicious” inflationary circle; and countries with current account deficits have depreciating exchange rates. The main message is that there is weak theoretical and empirical support for the majority of the conjectures. Only one proposition, relative PPP has strong empirical support but its policy relevance is weakened by the difficulty of interpreting departures from PPP. The remaining group for which there is inconclusive support presents the greatest challenge to research and policy as it includes the first conjecture.
VEGETATIVE AND REPRODUCTIVE MORPHOLOGY OF EUCHEUMA ISIFORME (SOLIERIACEAE, GIGARTINALES, RHODOPHYTA)1
Authors: Gabrielson Paul W.
Published: November 2004

Eucheuma isiforme (C. Agardh) J. Agardh exhibits a combination of vegetative and reproductive features that distinguish it from other critically studied genera in the Solieriaceae. The development of the multiaxial thallus, emphasizing the arrangement of periaxial cells around each axial file; presence of reproductive nemathecia that contain carpogonial branches and auxiliary cells; and post‐diploidization stages, including gonimoblast and pericarp initiation, stages of fusion cell formation, and carposporophyte development are described and illustrated for the first time in this species. The vegetative and reproductive features observed in E. isiforme are not diagnostic of any of the recently erected tribes in the Solieriaceae. Eucheuma appears most closely related to the Indian Ocean genus, Sarconema.
MORPHOLOGICAL VARIABILITY IN POPULATIONS OF CHRYSOPHYCEAN RESTING CYSTS. I. GENETIC (INTERCLONAL) AND ENCYSTMENT TEMPERATURE EFFECTS ON MORPHOLOGY1
Authors: Sandgren Craig D.
Published: November 2004

Many chrysophycean species produce resting cysts (statospores) with purportedly species‐specific morphology. I investigated variation in the cyst morphology of a single species that may result from genetic differences among the vegetative clones involved and from variation in the temperature of the environment during cyst development. Populations ofDinobryon cylindricumImhof cysts were produced under defined conditions in vitro and then sampled for morphological analysis based on SEM micrographs. Morphological data is presented and then used in a multivariate discriminant analysis to determine the utility of each morphological character in distinguishing the six populations studied. Results suggest that some features of cyst morphology (i.e. cyst diameter) are invariant among the populations, while other features show distinctive variation. The density of spines covering the cyst body as well as the morphology of those spines appear correlated to the specific clones involved, and thus may represent useful phenotypic genetic markers. The length and definition of both the spines and the cyst collar, on the other hand, are markedly influenced by encystment temperature. The implications of these findings for paleoecological studies is discussed.
KARYOTYPES AND REPRODUCTIVE SEASONALITY OF THE GENUS BANGIA (RHODOPHYTA) IN BRITISH COLUMBIA, CANADA1
Authors: Cole Kathleen M. , Hymes Beverly J. , Sheath Robert G.
Published: November 2004

Chromosome number and morphology as well as reproductive seasonally were examined in Bangia populations collected from 88 sites along the British Columbia coasts. Sexual filaments were recorded at 35 sites and asexual filaments at 58. Four different types of Bangia were determined. These were characterized by reproductive state and chromosome number, as well as by their seasonally and range of distribution. A summer‐fall three‐chromosome sexual type occurred from approximately 50° N northward and a winter‐spring four‐chromosome sexual type had a northerly limit of approximately 54° N, extending to the southernmost areas of British Columbia. Two asexual types occurred, exhibiting little seasonally, six‐chromosome populations throughout the coast and three‐chromosome populations at three southerly sites only. Karyograms were prepared for the four chromosomal types, assigning tentative centromere locations. Somatic chromosome pairing was reported for the first time in the Rhodophyta.
EVOLUTIONARY STRATEGIES IN A TROPICAL BARRIER REEF SYSTEM: FUNCTIONAL‐FORM GROUPS OF MARINE MACROALGAE1
Authors: Littler Mark M. , Littler Diane S. , Taylor Phillip R.
Published: November 2004

Predictions of an evolutionary model were examined for 43 tropical macroalgae using a functional‐form group approach. The ranking from high to low primary producers (Sheet‐ and Filamentous‐Groups > Coarsely Branched‐ and Thick Leathery‐Groups > Jointed Calcareous‐ and Crustose‐Groups), and data from the literature, support the hypothesis that persistent forms which allocate resources for environmental resistance, interference competition or antiherbivory defenses do so at the cost of lower primary production rates. The results for percent thallus lost to fish grazing over a 24 h period support the hypothesis that members of the Thick Leathery‐, Jointed Calcareous‐ and Crustose‐Groups have evolved antipredator defenses, with a tendency for decreasing herbivore resistance toward the Sheet‐ and Filamentous‐Groups. The most heavily‐calcified species (e.g. crustose corallines) ranked among the most grazer resistant as did the thick rubbery or leathery species. The ranking of functional‐form group means for resistance to predation was as follows: Filamentous‐Group (62% lost‐24 h−1), Sheet‐Group (42%), Coarsely Branched‐Group (33%), Jointed Calcareous‐Group (10%), Thick Leathery‐Group (7%) and Crustose‐Group (0%), in accordance with the hypothesis. The algal groups generally showed an increase in mean penetration toughness from filaments (<200 g‐cm−2 to shear thallus) to sheets (216 g·cm2), coarsely branched forms (328 g·cm−2) and thick leathery species (1800 g·cm−2) in agreement with the predictions of the model. Contrary to earlier findings, there was no consistent gradation between the first four groups (i.e. fleshy algae) based on calorific values. However, in partial support of the functional‐form model, a seven‐fold difference was noted when the mean for these groups (1.7 kcal·g−1) was compared with that of the Jointed Calcareous‐ and Crustose‐Groups (0.2 kcal·g−1. The functional‐form group approach appears to have powerful capabilities in that it can indicate important morphological‐metabolic‐ecological interactions in a given community, where the macroalgae are known, without the need to examine each population in detail and without being constrained to a specific habitat or geographical region.
SEASONAL FLUCTUATIONS IN TISSUE NITROGEN FOR FIVE SPECIES OF PERENNIAL MACROALGAE IN RHODE ISLAND SOUND1
Authors: Asare Seth O. , Harlin Marilyn M.
Published: November 2004

Tissue nitrogen was assessed monthly for 16 months in five species of perennial macroalgae representing three phyla at one location in Rhode Island Sound. The species showed a remarkable similarity in their pattern of seasonal fluctuation in both nitrate and total nitrogen. The period of greatest accumulation (January through March) coincided with the period of highest concentration of inorganic nitrogen in the water, and for most of these algae it was also the time of‐least growth. Conversely, the period of lowest tissue nitrogen (50% of the winter value, May through July) coincided with the period of lowest inorganic nitrogen in the water and highest algal growth. The greatest accumulation of nitrate was found in Laminaria saccharina (L.) Lamour. (80 μmol·g dry wt.−1), four times as much as that measured simultaneously in the other species and 560 times the ambient concentration. By April the concentration of internal nitrate had dropped to nearly undetectable levels, but in August it began to accumulate again—a pattern that was repeated in Chondrus crispus Stackh. In Ascophyllum nodosum (L.) Le Jolis, Fucus vesiculosus L. and Codium fragile subsp. tomentosoides (Van Goor) Silva, the period of negligible internal nitrate level extended from March to December. The greatest concentration of total tissue nitrogen was measured in C. crispus (4.8% dry wt.), double the maximum in L. saccharina (2.3% dry wt.).
MORPHOGENESIS OF MONOSTROMA OXYSPERMUM (KÜTZ.) DOTY (CHLOROPHYCEAE) IN AXENIC CULTURE, ESPECIALLY IN BIALGAL CULTURE1
Authors: Tatewaki Masakazu , Provasoli Luigi , Pintner Irma J.
Published: November 2004

The typical morphology of Monostroma oxyspermum (Kütz.) Doty is lost in axenic culture. In synthetic media of the ASP type, it grows as a colony‐like mass composed of round cells with numerous rhizoids. Such a mass is a fragile structure which falls apart upon shaking, or slight touch, into small cell‐groups and single cells or cells with a long rhizoid. Only temporary saccate or monostromatic fronds appear and reach 1–2 mm in length when grown in enriched seawater media, but disintegrate and become a colony‐like mass. The typical morphology is easily restored by adding at specific intervals filtrates of bacterial cultures and supernatant medium from axenic brown and red algal cultures to the basal medium (ASP7), or by reinfecting the Monostroma with an appropriate bacterial flora. Furthermore, the typical morphology in also maintained by bialgal cultures between Monostroma and other axenic strains of various species of seaweeds except the species belonging to the Chlorophyceae. Monostroma thus appears to utilize some substances released by most species of brown and red algae for its typical growth. Active substances released by bacteria, brown and red algae have not yet been identified and purified. However, it is demonstrated that in axenic cultures many species of seaweeds produce active extracellular substances which play an important role in growth and Morphogenesis of other species of seaweeds.
CELL ENLARGEMENT IN SKELETONEMA COSTATUM (BACILLARIOPHYCEAE)1
Authors: Gallagher Jane C.
Published: November 2004

Skeletonema costatum (Grev.) Cl. exhibits an asexual means, of increasing cell size that is more common than auxosporulation. This phenomenon accounts for the genetic stability of S. costatum in culture and for the deficiency of heterozygotes in natural populations, and has important implications far the life history of this species.
Peeling Away the Populist Rhetoric: Toward a Taxonomy of Anti‐Tax Ballot Initiatives
Authors: Smith Daniel A.
Published: November 2004

Scholars have devoted considerable attention to both the fiscal and policy impact of tax and expenditure limitation ballot initiatives. This article instead examines how statewide anti‐tax measures come to be placed before the general public for popular votes. It critically assesses six anti‐tax measures on statewide ballots in 1996, questioning the wisdom that they were populist undertakings. While tax crusaders continue to draw on grassroots themes and use populist rhetoric, there are important differences across the groups sponsoring the six anti‐tax measures, including their organizational history, professionalization, membership, and sources of financial support.
Butterfly response to severe ENSO‐induced forest fires in Borneo
Authors: Cleary Daniel F. R. , Grill Andrea
Published: November 2004

Abstract.  1. Little is known about animal community response to severe El Niño Southern Oscillation (ENSO)‐induced fire events. Here the response of butterflies to the 1997/98 ENSO‐induced fire event in East Kalimantan (Indonesian Borneo) is assessed. In addition to the community‐wide study, a detailed assessment of the lycaenid Jamides celeno is made.

2. Species richness declined significantly from 211 species pre‐ENSO to 39 species post‐ENSO and community composition changed significantly. Along with the decline in species richness there was a marked increase in dominance. Jamides celeno, for example, increased from 3% of the pre‐ENSO assemblage to 58% of the post‐ENSO assemblage. Like J. celeno, most of the species in the post‐ENSO assemblage were generalists; most of the specialist species having disappeared from pre‐ to post‐ENSO.

3. The major host plant used by J. celeno was the abundant resprouting Fordia splendidissima. Furthermore, significantly more eggs were laid on plants with the crazy ant, Anoplolepis gracilipes, present than on plants with other ants or no ant attendance. Caterpillar presence was significantly higher on plants tended by ants than on untended plants.

4. The median distance moved by J. celeno was 30 m with a maximum recorded distance of 290 m.

5. The abundance of J. celeno and other generalists in the post‐ENSO assemblage at Wanariset was probably related to their ability to utilise the few available resources after the fire (e.g. F. splendidissima resprouts), their presence in degraded habitats surrounding the Wanariset forest, and their ability to disperse successfully by either being strong fliers (e.g. Euploea spp.) or being able to attain very high population sizes and thereby produce a surplus of dispersers (e.g. J. celeno).
Coexistence of natural enemies in a multitrophic host–parasitoid system
Authors: Bonsall Michael B. , Hassell Michael P. , Reader Patricia M. , Jones T. Hefin
Published: November 2004

Abstract. 1. This study explored the temporal and spatial aspects of coexistence over many generations in a multispecies host–parasitoid assemblage.

2. The long‐term interaction between the cabbage root fly,Delia radicum(Diptera: Anthomyiidae), and two of its natural enemies,Trybliographa rapae(Hymenoptera: Fitigidae) andAleochara bilineata(Coleoptera: Staphylinidae), in a cultivated field at Silwood Park over 19 years was explored.

3. Although time series showed that the populations were regulated, the impact of the natural enemies was highly variable. Within‐year determinants showed that the spatial response of the specialist parasitoid,T. rapae, was predominantly independent of host density whileA. bilineataacted simply as a randomly foraging generalist parasitoid.

4. These findings are compared and contrasted with an earlier investigation of the same system when only the first 9 years of the time series were available. This study demonstrated the potential of long‐term field studies for exploring hypotheses on population regulation, persistence, and coexistence.
Psychosocial, Behavioral, and Biological Aspects of Chronic Diseases
Authors: Schneiderman Neil
Published: November 2004

Behavioral, psychosocial, and societal risk factors have been associated with several chronic diseases. Biological processes closely linked to lifestyle, stress, and psychological status appear to mediate the associations. Lifestyle and psychosocial interventions have been developed to prevent and manage chronic diseases. Field and laboratory studies help to specify causal pathways connecting lifestyle and psychosocial variables to disease processes. However, large-scale randomized clinical trials are required to determine whether interventions lower rates of illness and death.
The changing scene of the regulation of medicines in the UK. Paper from The Use of Medicines: Regulation & Clinical Pharmacology in the 21st Century Symposium – December 2003
Authors: Breckenridge Alasdair
Published: November 2004

The Medicines and Healthcare products Regulatory Agency was established in April 2003 by the merger of the Medicines Control Agency (MCA) and the Medical Devices Agency (MDA). This paper describes the scientific and organizational basis for the merger and describes the various challenges facing this new Agency.
Risk : benefit assessment of old medicines
Authors: Garattini Silvio , Bertelé Vittorio
Published: November 2004

Any meaningful discussion about the present value of old drugs requires appropriate comparisons with new drugs. While there is noisy propaganda claiming the superiority of new drugs, the evidence supporting these claims is often scanty and poor. Therefore, the database utilizable to evaluate old and new drugs is incomplete and fragile. There are several reasons, including the poor dossiers presented for the approval of new drugs, the lack of comparisons aimed at showing superiority of new drugs, the bias frequently involved in clinical trials and the conflict of interests. This brief discussion reviews these questions and gives some examples by comparing diuretics and new antihypertensive agents, ticlopidine and clopidogrel, and atypical and classical antipsychotic agents.
Influence of ketoconazole on azimilide pharmacokinetics in healthy subjects
Authors: El Mouelhi Mohamed , Worley Dan J. , Kuzmak Barbara , Destefano Anthony J. , Thompson Gary A.
Published: November 2004

Aim  To assess the influence of ketoconazole on azimilide pharmacokinetics.

Methods  A two‐period randomized crossover study was conducted in healthy male and female subjects (19–45 years). Placebo or 200 mg ketoconazole were administered orally every 24 h for 29 days. On day 8, a single oral dose of 125 mg azimilide dihydrochloride was coadministered following an overnight fast. Blood samples were obtained prior to and for 22 days following azimilide dihydrochloride administration. The plasma protein binding of azimilide was also assessed at 6 h after dosing.

Results  Following ketoconazole administration, a 16% increase in azimilide AUC (90% confidence interval (CI) 112%, 120%), a 12% increase in Cmax (95% CI 107%, 116%), a 13% increase in t1/2,z (95% CI 107%, 120%) and a 14% decrease in CLo (95% CI 82%, 90%) were observed.

Conclusions  The changes in azimilide pharmacokinetics following ketoconazole treatment are not clinically important since the 90% CI for the AUC fell within the prespecified range of 80–125%. Thus, no clinically important drug interactions are expected when azimilide dihydrochloride is coadministered with CYP3A4 inhibitors.
A semimechanistic and mechanistic population PK–PD model for biomarker response to ibandronate, a new bisphosphonate for the treatment of osteoporosis
Authors: Pillai Goonaseelan , Gieschke Ronald , Goggin Timothy , Jacqmin Philippe , Schimmer Ralph C. , Steimer Jean‐Louis
Published: November 2004

Aims

Ibandronate, a highly potent nitrogen‐containing bisphosphonate, is the subject of an ongoing clinical development programme that aims to maximize the potential of simplified, less frequent oral and intravenous (i.v.) administration in osteoporosis. A modelling and simulation project was undertaken to characterize further the clinical pharmacology of ibandronate and identify convenient intermittent oral and i.v. regimens for clinical evaluation.

Methods and results

Using selected data from clinical studies involving 174 women with postmenopausal osteoporosis (PMO), a classical multicompartmental pharmacokinetic‐pharmacodynamic (PK‐PD) model was developed that accurately described the PK of i.v. ibandronate in plasma and urine and urinary excretion of the C‐telopeptide of the α chain of type I collagen (uCTX), a sensitive biomarker of PD response to ibandronate. To reduce processing times, the classical PK‐PD model was simplified using a ’kinetics of drug action’ or kinetic (K)‐PD model (i.e. a dose‐response model as opposed to a dose‐concentration‐response model). The performance of the K‐PD model was evaluated by fitting data simulated with the PK‐PD model under various dosing regimens. The simplified model produced a virtually indistinguishable fit of the data from that of the PK‐PD model. The K‐PD model was extended to consider the influence of supplemental therapy (calcium with or without vitamin D) on the PD response and validated by retrospectively simulating the uCTX response in a prior Phase III and Phase II/III study of i.v. ibandronate, given once every 3 months, in 3380 women with PMO. The observed median uCTX responses at the scheduled assessment points in the completed studies were within the distribution of the simulated responses. The K‐PD model for i.v. ibandronate was extended further to allow simultaneous fitting of uCTX responses after i.v. and oral administration in 676 postmenopausal women with osteoporosis, and validated by retrospectively simulating the data observed in a Phase I study of oral daily ibandronate in 180 women with PMO. The K‐PD model adequately described the uCTX response after oral dosing.

Conclusions

This validated K‐PD model is currently being used to evaluate a range of novel intermittent oral and i.v. ibandronate regimens in an ongoing clinical development programme.
Soil organic carbon stocks in Flemish grasslands: how accurate are they?
Authors: Mestdagh I. , Lootens P. , Van Cleemput O. , Carlier L.
Published: November 2004

Articles 3·3 and 3·4 of the Kyoto protocol provide Annex I countries the possibility to reduce greenhouse gas emissions through the sequestration of carbon (C) in their terrestrial ecosystems. For such accounting, the 1990 flux is needed and, therefore, a correct knowledge of the baseline (1990) C stocks is necessary. In addition, a correct methodology should be used to investigate the capacity of ecosystems to sequester C through changes in land use or management by the end of the first commitment period (2008–2012). At national and regional scales, formulation of baseline C stocks in terrestrial ecosystems is difficult and uncertain. Differences in method of analysis, sampling depth of soil, lack of sufficient C data and the necessity to extrapolate C data to total soil organic C stocks, provide problems when comparing databases with each other. In this study, three extrapolation models were compared with the classical layer‐based method to determine the model with the best fit. The model with the best predictions, in relation to the classical layer‐based model, uses recent soil C profiles for estimating the parameter k, which represents the decrease in the proportion of soil organic C with depth, and for extrapolating the C data available for 1990 and 2000 to a depth of 1 m. The other two models gave large underestimates.