bluuebunny/crossref_metadata_2025 huggingface dataset:
Trajectories and energy transfer of saltating particles onto rock surfaces: Application to abrasion and ventifact formation on Earth and Mars
Authors: Bridges Nathan T. , Phoreman James , White Bruce R. , Greeley Ronald , Eddlemon Eric E. , Wilson Gregory R. , Meyer Christine J.
Published: December 2005

The interaction between saltating sand grains and rock surfaces is assessed to gauge relative abrasion potential as a function of rock shape, wind speed, grain size, and planetary environment. Many kinetic energy height profiles for impacts exhibit a distinctive increase, or kink, a few centimeters above the surface, consistent with previous field, wind tunnel, and theoretical investigations. The height of the kink observed in natural and wind tunnel settings is greater than predictions by a factor of 2 or more, probably because of enhanced bouncing off hard ground surfaces. Rebounded grains increase the effective flux and relative kinetic energy for intermediate slope angles. Whether abrasion occurs, as opposed to simple grain impact with little or no mass lost from the rock, depends on whether the grain kinetic energy (EG) exceeds a critical value (EC), as well as the flux of grains with energies above EC. The magnitude of abrasion and the shape change of the rock over time depends on this flux and the value of EG > EC. Considering the potential range of particle sizes and wind speeds, the predicted kinetic energies of saltating sand hitting rocks overlap on Earth and Mars. However, when limited to the most likely grain sizes and threshold conditions, our results agree with previous work and show that kinetic energies are about an order of magnitude greater on Mars.
Total ozone variation between 50° and 60°N
Authors: Zou Han , Zhou Libo , Gao Yongqi , Chen Xiaowei , Li Peng , Ji Chongping , Ma Shupo , Gao Dengyi
Published: December 2005

The merged TOMS/SBUV ozone data for 1979–2002 are used to analyze, with a linear regression model and the other approaches, the zonal distribution of ozone variations between 50° and 60°N, the seasonal cycle and trends, and the responses to the solar cycle, quasi‐biennial oscillation (QBO), El Niño–Southern Oscillation (ENSO) and Arctic Oscillation (AO). The seasonal ozone cycle shows ozone high over the north Pacific and low over the north Atlantic in winter, with a variability of 180 DU between 50° and 60°N. The maximum ozone trend obtained is over −5.3 ± 0.8%/decade at around 95°E in March. The anti‐phase ozone response to the equatorial QBO is about 8 DU, with a 28‐month period, in zonal average. In addition, the ozone responses to ENSO and AO are detected as 5 and 8 DU, respectively, between 95° and 190°E. The zonal inhomogeneity of ozone variations between 50° and 60°N is also discussed in this study.
Influence of a stochastic parameterization on the frequency of occurrence of North Pacific weather regimes in the ECMWF model
Authors: Jung T. , Palmer T. N. , Shutts G. J.
Published: December 2005

One common problem of many atmospheric circulation models is the overestimation of the mean westerly winds in the mid‐latitude North Pacific. This westerly wind bias is also a prominent feature in a recent version of the ECMWF model. Here we use the ECMWF model to investigate whether the use of stochastic parameterizations help reduce this error, using the concept of weather regimes. The focus is on the winter season when the atmospheric regime structure is most pronounced. It is shown that the operational version of the ECMWF stochastic physics scheme has little impact on the frequency of occurrence of North Pacific weather regimes. A recently developed scheme, however, which is based on combining a cellular automaton with a stochastic backscatter component, leads to substantial improvements in the simulation of the frequency of occurrence of North Pacific weather regimes and therefore a reduction of the westerly wind bias.
Triosephosphate isomerase deficiency: consequences of an inherited mutation at mRNA, protein and metabolic levels
Authors: Oláh Judit , Orosz Ferenc , Puskás László G. , Hackler László , Horányi Margit , Polgár László , Hollán Susan , Ovádi Judit
Published: December 2005

Triosephosphate isomerase (TPI) deficiency is a unique glycolytic enzymopathy coupled with neurodegeneration. Two Hungarian compound heterozygote brothers inherited the same TPI mutations (F240L and E145Stop), but only the younger one suffers from neurodegeneration. In the present study, we determined the kinetic parameters of key glycolytic enzymes including the mutant TPI for rational modelling of erythrocyte glycolysis. We found that a low TPI activity in the mutant cells (lower than predicted from the protein level and specific activity of the purified recombinant enzyme) is coupled with an increase in the activities of glycolytic kinases. The modelling rendered it possible to establish the steady-state flux of the glycolysis and metabolite concentrations, which was not possible experimentally due to the inactivation of the mutant TPI and other enzymes during the pre-steady state. Our results showed that the flux was 2.5-fold higher and the concentration of DHAP (dihydroxyacetone phosphate) and fructose 1,6-bisphosphate increased 40- and 5-fold respectively in the erythrocytes of the patient compared with the control. Although the rapid equilibration of triosephosphates is not achieved, the energy state of the cells is not ‘sick’ due to the activation of key regulatory enzymes. In lymphocytes of the two brothers, the TPI activity was also lower (20%) than that of controls; however, the remaining activity was high enough to maintain the rapid equilibration of triosephosphates; consequently, no accumulation of DHAP occurs, as judged by our experimental and computational data. Interestingly, we found significant differences in the mRNA levels of the brothers for TPI and some other, apparently unrelated, proteins. One of them is the prolyl oligopeptidase, the activity decrease of which has been reported in well-characterized neurodegenerative diseases. We found that the peptidase activity of the affected brother was reduced by 30% compared with that of his neurologically intact brother.
Integrin-linked kinase is responsible for Ca2+-independent myosin diphosphorylation and contraction of vascular smooth muscle
Authors: Wilson David P. , Sutherland Cindy , Borman Meredith A. , Deng Jing Ti , MacDonald Justin A. , Walsh Michael P.
Published: December 2005

Smooth muscle contraction is activated by phosphorylation at Ser-19 of LC20 (the 20 kDa light chains of myosin II) by Ca2+/calmodulin-dependent MLCK (myosin light-chain kinase). Diphosphorylation of LC20 at Ser-19 and Thr-18 is observed in smooth muscle tissues and cultured cells in response to various contractile stimuli, and in pathological circumstances associated with hypercontractility. MLCP (myosin light-chain phosphatase) inhibition can lead to LC20 diphosphorylation and Ca2+-independent contraction, which is not attributable to MLCK. Two kinases have emerged as candidates for Ca2+-independent LC20 diphosphorylation: ILK (integrin-linked kinase) and ZIPK (zipper-interacting protein kinase). Triton X-100-skinned rat caudal arterial smooth muscle was used to investigate the relative importance of ILK and ZIPK in Ca2+-independent, microcystin (phosphatase inhibitor)-induced LC20 diphosphorylation and contraction. Western blotting and in-gel kinase assays revealed that both kinases were retained in this preparation. Ca2+-independent contraction of calmodulin-depleted tissue in response to microcystin was resistant to MLCK inhibitors [AV25 (a 25-amino-acid peptide derived from the autoinhibitory domain of MLCK), ML-7, ML-9 and wortmannin], protein kinase C inhibitor (GF109203X) and Rho-associated kinase inhibitors (Y-27632 and H-1152), but blocked by the non-selective kinase inhibitor staurosporine. ZIPK was inhibited by AV25 (IC50 0.63±0.05 μM), whereas ILK was insensitive to AV25 (at concentrations as high as 100 μM). AV25 had no effect on Ca2+-independent, microcystin-induced LC20 mono- or di-phosphorylation, with a modest effect on force. We conclude that direct inhibition of MLCP in the absence of Ca2+ unmasks ILK activity, which phosphorylates LC20 at Ser-19 and Thr-18 to induce contraction. ILK is probably the kinase responsible for myosin diphosphorylation in vascular smooth muscle cells and tissues.
Dynamics of thin free films with reaction-driven density and viscosity variations
Authors: Matar O. K. , Spelt P. D. M.
Published: December 2005

We study the dynamics of thin free viscous films in the presence of exothermic chemical reactions, which alter the film density and viscosity. We use long-wave theory and the assumption of rapid vertical diffusion to derive a coupled system of evolution equations for the film thickness, axial velocity, temperature, and reactant and product concentrations; appropriate closure relations are chosen for the dependence of the density and viscosity (both dynamic and bulk) on the product concentration and temperature. Analytical and numerical solutions of the evolution equations allow a full parametric study to be conducted. The results indicate that the film dynamics is primarily governed by density variations, which depend on competing factors: the increase in product concentration and temperature (due to the heat of reaction), which act to increase and decrease the density, respectively. Thus the film can collapse and rupture (expand) if the former (latter) effects outweigh the latter (former); here, rupture is driven by van der Waals forces.
Free energy of solvation from molecular dynamics simulation applying Voronoi-Delaunay triangulation to the cavity creation
Authors: Goncalves Paulo F. B. , Stassen Hubert
Published: December 2005

The free energy of solvation for a large number of representative solutes in various solvents has been calculated from the polarizable continuum model coupled to molecular dynamics computer simulation. A new algorithm based on the Voronoi-Delaunay triangulation of atom-atom contact points between the solute and the solvent molecules is presented for the estimation of the solvent-accessible surface surrounding the solute. The volume of the inscribed cavity is used to rescale the cavitational contribution to the solvation free energy for each atom of the solute atom within scaled particle theory. The computation of the electrostatic free energy of solvation is performed using the Voronoi-Delaunay surface around the solute as the boundary for the polarizable continuum model. Additional short-range contributions to the solvation free energy are included directly from the solute-solvent force field for the van der Waals-type interactions. Calculated solvation free energies for neutral molecules dissolved in benzene, water, CCl4, and octanol are compared with experimental data. We found an excellent correlation between the experimental and computed free energies of solvation for all the solvents. In addition, the employed algorithm for the cavity creation by Voronoi-Delaunay triangulation is compared with the GEPOL algorithm and is shown to predict more accurate free energies of solvation, especially in solvents composed by molecules with nonspherical molecular shapes.
The ruby pressure standard to 150GPa
Authors: Chijioke Akobuije D. , Nellis W. J. , Soldatov A. , Silvera Isaac F.
Published: December 2005

A determination of the ruby high-pressure scale is presented using all available appropriate measurements including our own. Calibration data extend to 150GPa. A careful consideration of shock-wave-reduced isotherms is given, including corrections for material strength. The data are fitted to the calibration equation P=(A∕B)[(λ∕λ0)B−1] (GPa), with A=1876±6.7, B=10.71±0.14, and λ is the peak wavelength of the ruby R1 line.
A combined crossed-beam and theoretical investigation of radical-radical reaction dynamics of O(P3)+t-C4H9→OH+iso-C4H8
Authors: Nam Mi-Ja , Youn Sung-Eui , Li L. , Choi Jong-Ho
Published: December 2005

The oxidation reaction dynamics of a saturated hydrocarbon radical t-butyl leading to the isobutene +OH (XΠ2:v″=0, 1, 2) products in the gas phase were first investigated by applying a combination of high-resolution spectroscopy in a crossed-beam configuration and ab initio calculations. By comparing the nascent OH populations with the statistical theory, the reaction mechanism at the molecular level can be described in terms of two competing dynamic pathways: the major direct abstraction process leading to the inversion of vibrational populations, and the minor short-lived addition-complex process for hot rotational distributions.
Origin of pseudoelastic behavior in Ti–Mo-based alloys
Authors: Zhang L. C. , Zhou T. , Alpay S. P. , Aindow M. , Wu M. H.
Published: December 2005

High-resolution transmission electron microscopy and in situ x-ray diffraction analyses have been used to elucidate the compositional sensitivity of the deformation behavior in two β-Ti–Mo-based alloys. The alloy with 8% Mo exhibited conventional elastic∕plastic behavior in tension which corresponds to the irreversible formation of stress-induced orthorhombic α″ martensite. The alloy with 10% Mo exhibited a pronounced pseudoelastic response with recovery of ≈80% of the imposed tensile strain. This phenomenon is associated with the formation of another orthorhombic martensitic phase, which has not been reported previously, and this nucleates from pre-existing domains in the β matrix.
Compact electrically pumped nitrogen-doped 4H-SiC terahertz emitters operating up to 150 K
Authors: Lv P.-C. , Zhang X. , Kolodzey J. , Powell A.
Published: December 2005

We report a new type of electrically pumped THz source that emits at 9 THz with a maximum operating temperature of 150 K. The mechanism is based on dopant transitions in the 4H-SiC. The two nonequivalent donor sites of nitrogen in SiC were used to give the device a relatively high operating temperature and emission power. At a pumping current of 4.7 A at 4 K, the integrated spectral output power was 0.18 mWatt from the top surface with an area of 4mm2. These results suggest that high-temperature operating THz devices can be fabricated from doped SiC.
Tautomeric selectivity of the excited-state lifetime of guanine/cytosine base pairs: The role of electron-driven proton-transfer processes
Authors: Sobolewski Andrzej L. , Domcke Wolfgang , Hättig C.
Published: December 2005

The UV spectra of three different conformers of the guanine/cytosine base pair were recorded recently with UV-IR double-resonance techniques in a supersonic jet [Abo-Riziq, A., Grace, L., Nir, E., Kabelac, M., Hobza, P. & de Vries, M. S. (2005)
Proc
.
Natl
.
Acad
.
Sci
.
USA
102, 20–23]. The spectra provide evidence for a very efficient excited-state deactivation mechanism that is specific for the Watson–Crick structure and may be essential for the photostability of DNA. Here we report results of
ab initio
electronic-structure calculations for the excited electronic states of the three lowest-energy conformers of the guanine/cytosine base pair. The calculations reveal that electron-driven interbase proton-transfer processes play an important role in the photochemistry of these systems. The exceptionally short lifetime of the UV-absorbing states of the Watson–Crick conformer is tentatively explained by the existence of a barrierless reaction path that connects the spectroscopic
1
π π * excited state with the electronic ground state via two electronic curve crossings. For the non-Watson–Crick structures, the photochemically reactive state is located at higher energies, resulting in a barrier for proton transfer and, thus, a longer lifetime of the UV-absorbing
1
π π * state. The computational results support the conjecture that the photochemistry of hydrogen bonds plays a decisive role for the photostability of the molecular encoding of the genetic information in isolated DNA base pairs.
Reduced Paneth cell α-defensins in ileal Crohn's disease
Authors: Wehkamp Jan , Salzman Nita H. , Porter Edith , Nuding Sabine , Weichenthal Michael , Petras Robert E. , Shen Bo , Schaeffeler Elke , Schwab Matthias , Linzmeier Rose , Feathers Ryan W. , Chu Hiutung , Lima Heriberto , Fellermann Klaus , Ganz Tomas , Stange Eduard F. , Bevins Charles L.
Published: December 2005

The pathogenesis of Crohn′s disease (CD), an idiopathic inflammatory bowel disease, is attributed, in part, to intestinal bacteria that may initiate and perpetuate mucosal inflammation in genetically susceptible individuals. Paneth cells (PC) are the major source of antimicrobial peptides in the small intestine, including human α-defensins HD5 and HD6. We tested the hypothesis that reduced expression of PC α-defensins compromises mucosal host defenses and predisposes patients to CD of the ileum. We report that patients with CD of the ileum have reduced antibacterial activity in their intestinal mucosal extracts. These specimens also showed decreased expression of PC α-defensins, whereas the expression of eight other PC products either remained unchanged or increased when compared with controls. The specific decrease of α-defensins was independent of the degree of inflammation in the specimens and was not observed in either CD of the colon, ulcerative colitis, or pouchitis. The functional consequence of α-defensin expression levels was examined by using a transgenic mouse model, where we found changes in HD5 expression levels, comparable to those observed in CD, had a pronounced impact on the luminal microbiota. Thus, the specific deficiency of PC defensins that characterizes ileal CD may compromise innate immune defenses of the ileal mucosa and initiate and/or perpetuate this disease.
ATP hydrolysis is required to reset the ATP-binding cassette dimer into the resting-state conformation
Authors: Lu Gang , Westbrooks James M. , Davidson Amy L. , Chen Jue
Published: December 2005

ATP-binding cassette (ABC) transporters couple ATP binding and hydrolysis to the movement of substances across the membrane; conformational changes clearly play an important role in the transporter mechanism. Previously, we have shown that a dimer of MalK, the ATPase subunit of the maltose transporter from
Escherichia coli
, undergoes a tweezers-like motion in a transport cycle. The MalK monomer consists of an N-terminal nucleotide binding domain and a C-terminal regulatory domain. The two nucleotide-binding domains in a dimer are either open or closed, depending on whether ATP is present, while the regulatory domains maintain contacts to hold the dimer together. In this work, the structure of MalK in a posthydrolysis state is presented, obtained by cocrystallizing MalK with ATP-Mg
2+
. ATP was hydrolyzed in the crystallization drop, and ADP-Mg
2+
was found in the resulting crystal structure. In contrast to the ATP-bound form where two ATP molecules are buried in a closed interface between the nucleotide-binding domains, the two nucleotide-binding domains of the ADP-bound form are open, indicating that ADP, unlike ATP, cannot stabilize the closed form. This conclusion is further supported by oligomerization studies of MalK in solution. At low protein concentrations, ATP promotes dimerization of MalK, whereas ADP does not. The structures of dimeric MalK in the nucleotide-free, ATP-bound, and ADP-bound forms provide a framework for understanding the nature of the conformational changes that occur in an ATP-binding cassette transporter hydrolysis cycle, as well as how conformational changes in MalK are coupled to solute transport.
Dynamic patterns of adaptive radiation
Authors: Gavrilets Sergey , Vose Aaron
Published: December 2005

Adaptive radiation is defined as the evolution of ecological and phenotypic diversity within a rapidly multiplying lineage. When it occurs, adaptive radiation typically follows the colonization of a new environment or the establishment of a “key innovation,” which opens new ecological niches and/or new paths for evolution. Here, we take advantage of recent developments in speciation theory and modern computing power to build and explore a large-scale, stochastic, spatially explicit, individual-based model of adaptive radiation driven by adaptation to multidimensional ecological niches. We are able to model evolutionary dynamics of populations with hundreds of thousands of sexual diploid individuals over a time span of 100,000 generations assuming realistic mutation rates and allowing for genetic variation in a large number of both selected and neutral loci. Our results provide theoretical support and explanation for a number of empirical patterns including “area effect,” “overshooting effect,” and “least action effect,” as well as for the idea of a “porous genome.” Our findings suggest that the genetic architecture of traits involved in the most spectacular radiations might be rather simple. We show that a great majority of speciation events are concentrated early in the phylogeny. Our results emphasize the importance of ecological opportunity and genetic constraints in controlling the dynamics of adaptive radiation.
Locating high-affinity fatty acid-binding sites on albumin by x-ray crystallography and NMR spectroscopy
Authors: Simard J. R. , Zunszain P. A. , Ha C.-E. , Yang J. S. , Bhagavan N. V. , Petitpas I. , Curry S. , Hamilton J. A.
Published: December 2005

Human serum albumin (HSA) is a versatile transport protein for endogenous compounds and drugs. To evaluate physiologically relevant interactions between ligands for the protein, it is necessary to determine the locations and relative affinities of different ligands for their binding site(s). We present a site-specific investigation of the relative affinities of binding sites on HSA for fatty acids (FA), the primary physiological ligand for the protein. Titration of HSA with [
13
C]carboxyl-labeled FA was used initially to identify three NMR chemical shifts that are associated with high-affinity binding pockets on the protein. To correlate these peaks with FA-binding sites identified from the crystal structures of FA–HSA complexes, HSA mutants were engineered with substitutions of amino acids involved in coordination of the bound FA carboxyl. Titration of [
13
C]palmitate into solutions of HSA mutants for either FA site four (R410A/Y411A) or site five (K525A) within domain III of HSA each revealed loss of a specific NMR peak that was present in spectra of wild-type protein. Because these peaks are among the first three to be observed on titration of HSA with palmitate, sites four and five represent two of the three high-affinity long-chain FA-binding sites on HSA. These assignments were confirmed by titration of [
13
C]palmitate into recombinant domain III of HSA, which contains only sites four and five. These results establish a protocol for direct probing of the relative affinities of FA-binding sites, one that may be extended to examine competition between FA and other ligands for specific binding sites.
Unbiased selection of localization elements reveals cis-acting determinants of mRNA bud localization in Saccharomyces cerevisiae
Authors: Jambhekar Ashwini , McDermott Kimberly , Sorber Katherine , Shepard Kelly A. , Vale Ronald D. , Takizawa Peter A. , DeRisi Joseph L.
Published: December 2005

Cytoplasmic mRNA localization is a mechanism used by many organisms to generate asymmetry and sequester protein activity. In the yeast
Saccharomyces cerevisiae
, mRNA transport to bud tips of dividing cells is mediated by the binding of She2p, She3p, and Myo4p to coding regions of the RNA. To date, 24 bud-localized mRNAs have been identified, yet the RNA determinants that mediate localization remain poorly understood. Here, we used nonhomologous random recombination to generate libraries of sequences that could be selected for their ability to bind She-complex proteins, thereby providing an unbiased approach for minimizing and mapping localization elements in several transported RNAs. Analysis of the derived sequences and predicted secondary structures revealed short sequence motifs that mediate binding to the She complex and RNA localization to the bud tip
in vivo
. A predicted single-stranded core CG dinucleotide appears to be an important component of the RNA–protein interface, although other nucleotides contribute in a context-dependent manner. Our findings further our understanding of RNA recognition by the She complex, and the methods used here should be applicable for elucidating minimal RNA motifs involved in many other types of interactions.
The nematode-trapping efficacy of two chlamydospore-forming fungi against Haemonchus contortus in sheep
Authors: Chauhan J.B. , Sanyal P.K. , Subramanian R.B.
Published: December 2005

An in vitro study was carried out to determine efficacy of Indian isolates of the nematode-trapping fungi Arthrobotrys musiformis and Duddingtonia flagrans to capture infective larvae of Haemonchus contortus. These fungi have previously been screened and selected for their survival in the gastrointestinal tract of sheep without losing growth and nematode capturing potential. Following the feeding of chlamydospores of these two fungi alone or in combination in sheep experimentally infected with Haemonchus contortus, coprocultures were set up to enumerate the infective third stage larvae. The number of larvae captured from faeces of fungus-fed sheep was significantly higher compared with fungus-unfed controls irrespective of the fungus used. The fungal combination produced no antagonistic effect and thus can be used as efficiently as the fungi alone in the biological control of animal parasitic nematodes.
Soil-transmitted helminths and haemoglobin status among Afghan children in World Food Programme assisted schools
Authors: Gabrielli A.F. , Ramsan M. , Naumann C. , Tsogzolmaa D. , Bojang B. , Khoshal M.H. , Connolly M. , Stothard J.R. , Montresor A. , Savioli L.
Published: December 2005

In recent years there have been major socio-economic changes within Afghanistan such that the present public health burden of soil-transmitted helminths (STH), especially that within school-aged children, remains to be determined. A baseline parasitological survey was therefore carried out in four defined areas of Afghanistan to better assess the distribution, prevalence and intensity of STH infections prior to a nationwide de-worming campaign beginning within World Food Programme assisted schools. A cross-sectional examination of 1001 children aged between 8 and 15 years old revealed that approximately half (47.2%) were infected with at least one STH. Infections with Ascaris lumbricoides were most widespread (40.9%) and elevated prevalences were detected in urban environments; for example, schoolchildren in Kabul were more likely to be infected (OR=2.2, 95% CI 1.6–3.0) than elsewhere and these infections were often of higher intensity (OR=7.6, 95% CI 4.9–11.8). Trichuris trichiura (9.9%) and hookworms (0.7%), previously unknown from Afghanistan, were encountered. The blood haemoglobin concentration of surveyed children was also assessed: 4% resulted to be anaemic (Hb<11 g dl−1), and 0.4% to be severely anaemic (Hb<7 g dl−1).
Toxicity of cadmium and zinc mixtures to the decaudized cercarial life span of Diplostomum spathaceum
Authors: Morley N.J. , Crane M. , Lewis J.W.
Published: December 2005

The effects of cadmium and zinc mixtures at concentrations ranging from 0.1 to 10,000 μg l−1 on the life-span of decaudized cercarial bodies (cercariae that have shed their tails) of Diplostomum spathaceum (Trematoda: Diplostomatidae) was investigated. Cercariae were exposed to metal mixtures of equal and unequal concentrations, and a low-dose pre-treatment followed by a high-dose exposure mixtures. Metal mixtures demonstrated variable effects on decaudized cercariae either by increasing or reducing their life-span compared to single metal exposures dependent on concentration and the type of mixed metal treatment. Prolonged exposure to equal metal mixtures at low concentrations (0.1–100 μg l−1) resulted in a reduction in the life-span of decaudized cercariae at 0.1 and 100 μg l−1 in those individuals decaudized during the initial 24 h exposure period compared with those decaudized during the final 24 h period of cercarial survival, whilst in controls there was no significant life-span change between the two time periods. Decaudized cercariae which were exposed to low concentrations (0.1–100 μg l−1) of equal metal mixtures were also evaluated for their role as an indicator of larval ‘fitness’ for migrating through the tissues of their target fish host for those individuals decaudized during the initial 24 h exposure period, and demonstrated only a limited change in their life-span compared to control and single metal exposures. The importance of metal mixtures in parasite establishment in the fish host is discussed.
Process-oriented training in breastfeeding alters attitudes to breastfeeding in health professionals
Authors: Ekström Anette , Widström Ann-Marie , Nissen Eva
Published: December 2005

Aim: The purpose of the study was to measure the attitudes of antenatal midwives and postnatal nurses to breastfeeding before and after common, process-oriented breastfeeding training. Method: Antenatal centres and child-health centres in 10 municipalities were randomized to either an intervention or a control group. The antenatal midwives and postnatal nurses in the intervention group were together given process-oriented breastfeeding training and were, in addition, asked to develop a common breastfeeding policy. A previously developed instrument was used to measure the effects of a training programme on breastfeeding attitudes among midwives and postnatal nurses. It consisted of four scales measuring a person's attitudes toward breastfeeding in four dimensions: regulating, facilitating, disempowering, and breastfeeding-antipathy attitudes. A mean score was calculated for each individual on these four dimensional scales. The higher the score, the stronger the attitude. Results: After one year, the intervention group reduced their scores on the regulating scale when compared with the control group (p<0.001). The intervention group decreased their scores on the regulating scale and increased their scores on the facilitating scale over the first year after training. The control group also significantly increased their scores on the facilitating scale. When the results were analysed profession-wise, the postnatal nurses in the intervention group decreased their scores on the regulating and disempowering scales and increased their scores on the facilitating scale. In contrast, the midwives in the intervention group decreased their scores only on the breastfeeding antipathy scale. The control group midwives decreased their scores on the disempowering scale. No differences were found among the postnatal nurses in the control group. Conclusion: Process-oriented breastfeeding training made both antenatal midwives and postnatal nurses better disposed to breastfeeding; postnatal nurses in particular improved their attitudes. Attitudes to breastfeeding tended to be stable over time, but process-oriented training lowered the scores a little on the regulating scale, suggesting that after this kind of training counsellors would find it less necessary to schedule and control the mothers' breastfeeding behaviour.
Dual source support and control at work in relation to poor health
Authors: Oxenstierna Gabriel , Ferrie Jane , Hyde Martin , Westerlund Hugo , Theorell Töres
Published: December 2005

Background and aim: Social support and decision authority in relation to health has been examined in extensive research. However, research on the role of different constellations of support sources is conspicuously lacking. The aim of the present study is to describe the health of employees in eight contrasting situations that differ with regard to support from superiors and from workmates and with regard to decision authority. Men and women were studied separately. Study sample and methods: A large sample of Swedish employees (n=53,371, after exclusion of supervisors) who participated in a national work environment survey was utilized. In addition prospective long-term sick leave data (60 days or more during the 12 months after questionnaire completion) were collected from the national insurance register. Results: Employees who reported below median decision authority had higher prevalence of pains after work and general physical symptoms as well as a higher incidence of long-term sick leave than those with higher decision authority in all subgroups. Those with good support from both workmates and superiors had lower symptom prevalence and long-term sick leave incidence than those with poor support. The groups with either poor support from superiors or from workmates were in an intermediate category with regard to symptom prevalence. The group with good support from superiors but weak support from workmates, however, had as high long-term sick leave incidence as the group with poor support from both superiors and workmates. The patterns were similar for men and women. Conclusion: Long-term sick leave was related mainly to poor support from workmates. Prevalence of symptoms, on the other hand, was related to both sources of support and absence of both sources was associated with particularly high prevalence of physical symptoms. This illustrates that it is meaningful to separate the social support sources.
Haustorially Expressed Secreted Proteins from Flax Rust Are Highly Enriched for Avirulence Elicitors
Authors: Catanzariti Ann-Maree , Dodds Peter N. , Lawrence Gregory J. , Ayliffe Michael A. , Ellis Jeffrey G.
Published: December 2005

Rust fungi, obligate biotrophs that cause disease and yield losses in crops such as cereals and soybean (Glycine max), obtain nutrients from the host through haustoria, which are specialized structures that develop within host cells. Resistance of flax (Linum usitatissimum) to flax rust (Melampsora lini) involves the induction of a hypersensitive cell death response at haustoria formation sites, governed by gene-for-gene recognition between host resistance and pathogen avirulence genes. We identified genes encoding haustorially expressed secreted proteins (HESPs) by screening a flax rust haustorium-specific cDNA library. Among 429 unigenes, 21 HESPs were identified, one corresponding to the AvrL567 gene. Three other HESPs cosegregated with the independent AvrM, AvrP4, and AvrP123 loci. Expression of these genes in flax induced resistance gene–mediated cell death with the appropriate specificity, confirming their avirulence activity. AvrP4 and AvrP123 are Cys-rich proteins, and AvrP123 contains a Kazal Ser protease inhibitor signature, whereas AvrM contains no Cys residues. AvrP4 and AvrM induce cell death when expressed intracellularly, suggesting their translocation into plant cells during infection. However, secreted AvrM and AvrP4 also induce necrotic responses, with secreted AvrP4 more active than intracellular AvrP4, possibly as a result of enhanced formation of endoplasmic reticulum–dependent disulfide bonds. Addition of an endoplasmic reticulum retention signal inhibited AvrM-induced necrosis, suggesting that both AvrM and AvrP4 can reenter the plant cell after secretion in the absence of the pathogen.
Abundance and distribution of the tsetse flies, Glossina austeni and G. brevipalpis, in different habitats in South Africa
Authors: Esterhuizen J. , Kappmeier Green K. , Marcotty T. , Van Den Bossche P.
Published: December 2005

Abstract.  The distribution and abundance of Glossina austeni Newstead and Glossina brevipalpis Newstead (Diptera: Glossinidae) were studied in the three main vegetation types in Zululand, KwaZulu‐Natal, South Africa. During a period of 12 months, a trap transect consisting of 38 H‐traps traversing the three vegetation types was monitored. The Index of Apparent Abundance (IAA) for G. brevipalpis was high in indigenous forest and open grassland but lower in exotic plantations. Glossina austeni, on the other hand, was captured mainly in or adjacent to indigenous forest. The seasonal trend in the IAA did not differ between vegetation types. The findings on the distribution of G. brevipalpis are in contrast with the historic records. Historically, this species was considered to be restricted to areas with a dense overhead canopy and high relative humidity. The repercussions of these findings for the epidemiology of livestock trypanosomiasis and the control of tsetse in Zululand are discussed.
Field and laboratory studies on water conditions affecting the potency of VectoBac® (Bacillus thuringiensis serotype H‐14) against larvae of the blackfly, Simulium damnosum
Authors: Wilson M. D. , Akpabey F. J. , Osei‐Atweneboana M. Y. , Boakye D. A. , Ocran M. , Kurtak D. C. , Cheke R. A. , Mensah G. E. , Birkhold D. , Cibulsky R.
Published: December 2005

Abstract.  River water conditions that might influence the efficacy of VectoBac®, a formulation of the microbial insecticide Bacillus thuringiensis H‐14 Berliner against Simulium damnosum sensu lato Theobald (Diptera: Simuliidae) larvae were investigated. A standard formulation was assayed 130 times over 15 months using a mini‐gutter system at a field station beside the River Pra in Ghana. The lethal concentration (LC) values, river temperature, conductivity, turbidity and pH were analysed using univariate and multivariate statistics to identify which of these parameters influenced its performance. River temperature, conductivity and turbidity (in that order) were identified as having direct effects on the potency of VectoBac®. Water temperature and conductivity were negatively correlated, whereas turbidity and pH were positively correlated with LC values. Analyses of river water samples revealed that despite observed differences in total solids, sodium and potassium cations and chloride concentrations, all the parameters measured did not differ significantly between wet and dry seasons. A simple method for rearing S. damnosum s.l. in the laboratory was then adopted to study the effect of conductivity on potency of VectoBac® under controlled conditions. Increasing the conductivity of the water medium up to 3000 µS enhanced potency by about 42%, whereas increasing that of the insecticide alone raised it by 37%. The results obtained suggest that for effective use of VectoBac® for blackfly control in West Africa, river temperature, conductivity and turbidity should be taken into consideration, perhaps by only selecting rivers with optimal conditions for treatment. The laboratory‐based system developed for assaying the product overcomes the vagaries associated with field conditions and also the demand for huge logistic requirements of the mini‐gutter system, which has to be sited near rivers.
Immunohistochemical Localization of Distinct Angiotensin II AT1 Receptor Isoforms in the Kidneys of the Sprague‐Dawley Rat and the Desert Rodent Meriones Crassus
Authors: Al‐Qattan K. K. , Al‐Akhawand S. J. , Mansour M. H.
Published: December 2005

Employing a purified lgG fraction of a polyclonal anti‐AT1 receptor anti‐body, raised against a synthetic octapeptide encompassing residues 14–21 of the first extracellular domain of the AT1 polypeptide, selective AT1 receptor expression was immunohistochemically demonstrable within renal structures in Sprague‐Dawley (SD) rats and the desert rodent Meriones crassus. In both animal models, prominent AT1 receptor labelling was evident in renal vascular elements, particularly cortical inter‐lobular arteries (IA) as well as vasa recta bundles in the inner stripe of the outer medulla. Less intense labelling was observed among peritubular capillary endothelia within the deep cortex, and at both the outer stripe and the inter‐bundle regions of the inner stripe of the outer medulla. The binding of the anti‐peptide anti‐body was, however, lacking among glomeruli and, except for the intense labelling confined to basement membranes of Bowman's capsule of deep nephrons, was virtually absent in all renal tubular structures of both animal models. Structural assessment of the expressed AT1 receptors by two‐dimensional Western blotting revealed that a spectrum of structurally distinct AT1 receptor isoforms is expressed in the renal tissues of both animal models. This spectrum was constituted by isoforms of equal size (70 kDa) but distinct pls in SD rats, and of both different sizes (67–73 kDa) and isoelectric points in M. crassus. In either species, the charge and/or size heterogeneity of AT1 receptor isoforms may be attributed in part to differential post‐translational glycosylation mechanisms of the AT1 receptor polypeptide backbone. The potential for the differential glycosylation state of AT1 receptors to alter recognition properties may add another level of complexity to tissue‐specific and/or species‐specific mechanisms underlying angiotensin II interactions in the kidney.
EFFECT OF EXTRACORPOREAL SHOCKWAVE LITHOTRIPSY AND ENDOSCOPIC TREATMENT ON SYMPTOMS AND PANCREATIC FUNCTION IN PANCREATOLITHIASIS
Authors: Tada Tomoko , Ukita Takeo , Maetani Iruru , Sakai Yoshihiro , Igarashi Yoshinori
Published: December 2005

Aims:  To investigate the efficacy of extracorporeal shockwave lithotripsy (ESWL) combined with endoscopic treatment for pancreatolithiasis and assess the pancreatic functions after treatment.

Patients:  Forty‐eight cases with pancreatolithiasis in the main pancreatic duct (MPD) treated by ESWL combined with endoscopic treatments were investigated.

Methods:  The disappearance rate of abdominal symptoms, the frequency of admission for acute exacerbation of pancreatitis before and after treatment, the relationship of removal of pancreatic stones with recurrence and stricture of the MPD, and pancreatic functions before and after treatment were examined.

Results:  Treatment for pancreatolithiasis improved symptoms in 95.1% and significantly reduced the frequency of admission for 1 year from 1.4 to 0.2 on average. Pancreatic stones were excellently eliminated in 93.8%. Even in cases complicated with the stricture of MPD, combination with endoscopic techniques provided treatment efficacy comparable to that in cases without such complications. The Bentiromide test significantly improved within 3 months after treatment. It improved 1–2 and 2–3 years after treatment but there was no significant difference. Endocrine functions were maintained in 93.6%, 74.3%, 66.7%, and 64.3% within 3 months, 1–2 years, 2–3 years, and 3 or more years, respectively, after treatment.

Conclusions:  ESWL combined with endoscopic treatment provides comparable treatment efficacy in cases with and without stricture of the MPD. Treatment for pancreatolithiasis is useful for not only alleviating abdominal symptoms but also maintaining pancreatic exocrine function and management of the diabetes.
ENDOSCOPIC MANAGEMENT OF A DIEULAFOY‐LIKE LESION IN A DUODENAL DIVERTICULUM
Authors: Yoshino Shuro , Matsumoto Takayuki , Kurahara Koichi , Kobayashi Hiroyuki , Iida Mitsuo , Fuchigami Tadahiko
Published: December 2005

We present a 70‐year‐old man who had two episodes of melena during the preceding 8‐year period. He had a Dieulafoy‐like lesion in a diverticulum in the third portion of the duodenum. While emergency endoscopy revealed neither apparent blood nor clots around the diverticular orifice, there was a non‐bleeding vessel in the fundus of the diverticulum. The vessel ceased bleeding after argon plasma coagulation and, since then, the patient has not experienced bleeding. In cases of gastrointestinal bleeding of obscure origin, duodenal diverticulum should be considered as a possible source of bleeding, even when endoscopy discloses no apparent bleeding.
RELATION BETWEEN RESPIRATORY SUPPRESSION FROM SEDATION DURING ENDOSCOPY AND VITAL CAPACITY
Authors: Tomiki Yuichi , Shinmura Koji , Kasamaki Shinji , Terai Kiyoshi , Maeda Tsutomu , Takeda Ryohei , Takahashi Makoto , Yaginuma Yukihiro , Sakamoto Kazuhiro , Nakajima Takashi , Kamano Toshiki , Hayashida Yasuo
Published: December 2005

Background:  Respiratory suppression is observed during endoscopy under sedation. If respiratory suppression can be predicted before endoscopy, incidental complications can conceivably be prevented. In the present study, we focused on the relation between respiratory suppression from sedation and lung function.

Methods:  A total of 211 patients underwent respiratory function tests before the surgical operation and gave written informed consent individually to participate in this study. We investigated the relation between respiratory suppression from sedation and lung function. During the endoscopic procedure, when blood oxygen saturation (SpO2) fell to below 90%, the patient was evaluated as ‘respiratory suppression present’.

Results:  Sedation lowered SpO2 by an average of 6.0%, and was significantly lower than the prior to sedation blood oxygen saturation (PreSpO2). Compared to patients with SpO2 maintained up to 90%, patients with SpO2 fallen below 90% were significantly older, shorter in stature, lighter in bodyweight, and more commonly female. Furthermore, respiratory suppression from sedation was influenced by vital capacity (VC) and PreSpO2. Multivariate analysis was performed, and the receiver operating characteristic (ROC) curve constructed for the respiratory suppression prediction model based on age, height, VC and PreSpO2 yielded area under the curve (AUC) of 0.79. As VCpredict can be calculated from age and height, the three variables of age, height and VC in the above model were substituted with VCpredict resulting in a two‐factor model based on VCpredict and PreSpO2. The ROC curve of the two‐factor model had AUC of 0.77, which was slightly decreased but by no means inferior.

Conclusion:  Predicting respiratory suppression from VCpredict and PreSpO2 is clinically relevant with the additional benefit of simplicity.
Anaerobic redox cycling of iron by freshwater sediment microorganisms
Authors: Weber Karrie A. , Urrutia Matilde M. , Churchill Perry F. , Kukkadapu Ravi K. , Roden Eric E.
Published: December 2005

The potential for microbially mediated anaerobic redox cycling of iron (Fe) was examined in a first‐generation enrichment culture of freshwater wetland sediment microorganisms. Most probable number enumerations revealed the presence of significant populations of Fe(III)‐reducing (approximately 108 cells ml−1) and Fe(II)‐oxidizing, nitrate‐reducing organisms (approximately 105 cells ml−1) in the freshwater sediment used to inoculate the enrichment cultures. Nitrate reduction commenced immediately following inoculation of acetate‐containing (approximately 1 mM) medium with a small quantity (1% v/v) of wetland sediment, and resulted in the transient accumulation of NO2− and production of a mixture of gaseous end‐products (N2O and N2) and NH4+. Fe(III) oxide (high surface area goethite) reduction took place after NO3− was depleted and continued until all the acetate was utilized. Addition of NO3− after Fe(III) reduction ceased resulted in the immediate oxidation of Fe(II) coupled to reduction of NO3− to NH4+. No significant NO2− accumulation was observed during nitrate‐dependent Fe(II) oxidation. No Fe(II) oxidation occurred in pasteurized controls. Microbial community structure in the enrichment was monitored by denaturing gradient gel electrophoresis analysis of polymerase chain reaction‐amplified 16S rDNA and reverse transcription polymerase chain reaction‐amplified 16S rRNA, as well as by construction of 16S rDNA clone libraries for four different time points during the experiment. Strong similarities in dominant members of the microbial community were observed in the Fe(III) reduction and nitrate‐dependent Fe(II) oxidation phases of the experiment, specifically the common presence of organisms closely related (≥ 95% sequence similarity) to the genera Geobacter and Dechloromonas. These results indicate that the wetland sediments contained organisms such as Geobacter sp. which are capable of both dissimilatory Fe(III) reduction and oxidation of Fe(II) with reduction of NO3− to NH4+. Our findings suggest that microbially catalysed nitrate‐dependent Fe(II) oxidation has the potential to contribute to a dynamic anaerobic Fe redox cycle in freshwater sediments.