bluuebunny/crossref_metadata_2025 huggingface dataset:
Low plasma concentrations of diet-derived antioxidants in association with microalbuminuria in Indigenous Australian populations
Authors: ROWLEY Kevin , O'DEA Kerin , SU Qing , JENKINS Alicia J. , BEST James D.
Published: October 2003

Microalbuminuria is a risk factor for renal and cardiovascular diseases. Oxidant stress may contribute to vascular disease risk by promoting damage to renal and vascular tissues. This study examined the associations of plasma levels of diet-derived antioxidants with albuminuria in Australian population groups at high risk of renal and cardiovascular disease. Data on microalbuminuria and diet-derived plasma antioxidants were drawn from results of cross-sectional community-based risk factor surveys of Aboriginal and Torres Strait Islander peoples (n=698, 15 years and older). Prevalence of microalbuminuria ranged from 17–21%. After adjustment for age, gender, body mass index, diabetes, smoking status, plasma lipids and blood pressure, microalbuminuria was associated with significantly lower plasma concentrations of lycopene (-29%; P<0.001), β-carotene (-22%; P<0.001), α-carotene (-22%; P<0.001) and cryptoxanthin (-17%; P<0.001) compared with normalbuminuric persons. Significant associations of microalbuminuria with plasma concentrations of α-tocopherol, retinol, lutein plus zeaxanthin and homocysteine were absent. The data are consistent with a protective effect of diets rich in carotenoids on vascular endothelium and/or renal tissues, and support the need for interventions to address affordable food supplies and dietary quality among Indigenous Australians.
Differences in mouse strain influence leukocyte and immunoglobulin phenotype response to Porphyromonas gingivalis
Authors: Gemmell E. , Winning T. A. , Carter C. L. , Ford P. J. , Bird P. S. , Ashman R. B. , Grieco D. A. , Seymour G. J.
Published: October 2003

This study examined the nature of the infiltrating cells in Porphyromonas gingivalis‐induced lesions and immunoglobulins in the serum samples of BALB/c (H‐2d), C57BL6 (H‐2b), DBA/2J (H‐2d) and CBA/CaH (H‐2k) mice. Mice were immunized intraperitoneally with P. gingivalis outer membrane antigens or sham‐immunized with phosphate‐buffered saline followed by subcutaneous challenge with live organisms 1 week after the final immunization. The resulting skin abscesses were excised 7 days later, cryostat sections cut and an immunoperoxidase method used to detect the presence of CD4+ and CD8+ T‐cell subsets, CD14+ macrophages and CD19+ B cells. Peroxidase positive neutrophils and IgG1‐ and IgG2a‐producing plasma cells were also identified. Anti P. gingivalis IgG1 and IgG2a subclass antibodies were determined in serum obtained by cardiac puncture. Very few CD8+ T cells and CD19+ B cells were found in any of the lesions. The percentages of CD4+ cells, CD14+ cells and neutrophils were similar in lesions of immunized BALB/c and C57BL6 mice, with a trend towards a higher percentage of CD14+ cells in sham‐immunized mice. The percentage of CD14+ cells was higher than that of CD4+ cells in immunized compared with sham‐immunized DBA/2J mice. The percentages of CD4+ and CD14+ cells predominated in immunized CBA/CaH mice and CD4+ cells in sham‐immunized CBA/CaH mice. The percentage of neutrophils in immunized CBA/CaH mice was significantly lower than that of CD14+ cells and CD4+ cells in sham‐immunized mice. IgG1+ plasma cells were more dominant than IgG2a+ cells in immunized BALB/c, C57BL6 and DBA/2J mice, whereas IgG2a+ plasma cells were more obvious in sham‐immunized mice. IgG2a+ plasma cells were predominant in immunized and sham‐immunized CBA/CaH mice. In the serum, specific anti‐P. gingivalis IgG2a antibody levels (Th1 response) were higher than IgG1 levels (Th2 response) in sham‐immunized CBA/CaH and DBA/2J mice. In immunized BALB/c mice, IgG2a levels were lower than IgG1 levels, while IgG2a levels were higher in immunized C57BL6 mice. In conclusion, this study has shown differences in the proportion of infiltrating leukocytes and in the subclasses of immunoglobulin produced locally and systemically in response to P. gingivalis in different strains of mice, suggesting a degree of genetic control over the response to P. gingivalis.
Construction of a pepO gene‐deficient mutant of Porphyromonas gingivalis: potential role of endopeptidase O in the invasion of host cells
Authors: Ansai T. , Yu W. , Urnowey S. , Barik S. , Takehara T.
Published: October 2003

Porphyromonas gingivalis has been isolated from lesions of advanced adult periodontitis, and implicated as a periodontal pathogen. We have previously cloned a novel endopeptidase, designated PepO, from P. gingivalis 381, which exhibited significant homology to human endothelin‐converting enzyme (ECE)‐1. In order to determine the nature and function of the PepO in the host, a pepO gene‐deficient mutant strain was constructed by allelic exchange mutagenesis using the ermF‐ermAM cassette. No endopeptidase activity was detected in the pepO‐deficient mutant. In addition, adherent HeLa (HEp‐2) cells were infected with the mutant and the two wild‐type strains for assessment of bacterial invasion by an antibiotic protection assay. The invasion efficiency of the mutant strain was about a quarter of the wild type strains. These results suggest that PepO is involved in the first step, i.e. invasion/lysis of mammalian cell membrane, which affects the kinetics of rate of invasion.
Induction of T‐cell apoptosis by Actinobacillus actinomycetemcomitans mutants with deletion of ltxA and cdtABC genes: possible activity of GroEL‐like molecule
Authors: Nalbant A. , Chen C. , Wang Y. , Zadeh H. H.
Published: October 2003

The pathogenic bacterium Actinobacillus actinomycetemcomitans expresses a leukotoxin (Ltx) and cytolethal distending toxin (CDT) with cytolytic properties. CDT also has cytostatic properties, inducing a G2 cell cycle block. The extent of the contribution of these, as well as other toxins, to the cytolytic and cytostatic activities of this microorganism have not been defined and the aim of this study was to determine their contribution. To that end, a naturally transformable A. actinomycetemcomitans clinical strain (D7S‐smooth) was used to construct a series of deletion mutants (ΔcdtA, ΔcdtB, ΔcdtC, ΔcdtABC, ΔltxA, ΔltxA/ΔcdtABC). Human peripheral blood mononuclear cells were incubated with cell‐associated and extracellular bacterial preparations. The ability of wild type and isogenic mutants to induce T‐cell apoptosis and cell cycle arrest was compared. The expression of ltxA and each of the cdt gene loci partially contributed to A. actinomycetemcomitans apoptosis, since each of the isogenic mutants exhibited reduced ability to induce T‐cell apoptosis. Conversely, the ability to induce cell cycle block was abolished in each of the cdt isogenic mutants. A mutant with simultaneous deletion of ltxA and cdtABC genes retained potent ability to induce apoptosis in its cell‐associated, but not extracellular, preparation. Neutralization with Escherichia coli anti‐GroEL monoclonal antibody, lead to significant diminution of apoptosis‐inducing activity of the ΔltxA/ΔcdtABC cell‐associated preparation. These data provide evidence for the expression of other A. actinomycetemcomitans cytolytic molecule(s) distinct from CDT and leukotoxin, with a possible role for GroEL‐like molecule in T‐cell apoptosis.
Isolation and characterization of genes differentially expressed during the interaction between apple fruit and Penicillium expansum
Authors: Sánchez‐Torres Paloma , González‐Candelas Luis
Published: October 2003

Differences in gene expression during the susceptible interaction between ‘Golden Delicious’ apple fruits and the fungus Penicillium expansum were investigated by differential display (DD) RT‐PCR. Partial cDNAs from 26 clones from both the fungus and the fruit were selected for nucleotide sequence determination and homology searches, and 20 were subsequently selected for further analyses. In a preliminary series of Northern blot analyses, 18 genes were confirmed as showing a higher expression level during the apple–fungus interaction than in control tissues. Southern analyses permitted an assignation of the fruit or fungal origin of each cDNA. Thirteen clones were derived from P. expansum and five from apple. A more detailed analysis of their expression patterns was conducted in an independent infection experiment confirming the differential expression for 12 of them. Among the differentially expressed genes were one fungal gene encoding an unknown protein and two apple genes, homologous to a β‐glucosidase and a phosphatase 2C, respectively, that were exclusively expressed during the infection process. Several up‐regulated P. expansum genes seem to mediate adaptive responses to the host environment.
Geomorphology and fish assemblages in a Piedmont river basin, U.S.A.
Authors: Walters D. M. , Leigh D. S. , Freeman M. C. , Freeman B. J. , Pringle C.M.
Published: October 2003

1. We investigated linkages between fishes and fluvial geomorphology in 31 wadeable streams in the Etowah River basin in northern Georgia, U.S.A. Streams were stratified into three catchment sizes of approximately 15, 50 and 100 km2, and fishes and geomorphology were sampled at the reach scale (i.e. 20–40 times stream width).

2. Non‐metric multidimensional scaling (NMDS) identified 85% of the among‐site variation in fish assemblage structure and identified strong patterns in species composition across sites. Assemblages shifted from domination by centrarchids, and other pool species that spawn in fine sediments and have generalised food preferences, to darter‐cyprinid‐redhorse sucker complexes that inhabit riffles and runs, feed primarily on invertebrates, and spawn on coarser stream beds.

3. Richness and density were correlated with basin area, a measure of stream size, but species composition was best predicted (i.e. |r| between 0.60–0.82) by reach‐level geomorphic variables (stream slope, bed texture, bed mobility and tractive force) that were unrelated to stream size. Stream slope was the dominant factor controlling stream habitat. Low slope streams had smaller bed particles, more fines in riffles, lower tractive force and greater bed mobility compared with high slope streams.

4. Our results contrast with the ‘River Continuum Concept’ which argues that stream assemblages vary predictably along stream size gradients. Our findings support the ‘Process Domains Concept’, which argues that local‐scale geomorphic processes determine the stream habitat and disturbance regimes that influence stream communities.
Invertebrate communities associated with a native (Vallisneria americana) and an alien (Trapa natans) macrophyte in a large river
Authors: Strayer David L. , Lutz Colleen , Malcom Heather M. , Munger Krista , Shaw William H.
Published: October 2003

1. We used a corer and a Downing box sampler to sample macroinvertebrates living on and beneath the introduced Trapa natans and the native Vallisneria americana in the freshwater tidal Hudson River, New York.

2. Densities of macroinvertebrates were higher in Trapa than in Vallisneria, and higher in the interior of plant beds than at their edges. These effects were largely a result of high plant biomass in Trapa beds and in bed interiors (the plants have similar surface area per unit mass).

3. The composition of both epiphytic and benthic macroinvertebrates differed distinctly between Trapa and Vallisneria, and also seasonally.

4. These compositional differences were not easily interpretable as rising from possible differences in oxygen concentrations, fish predation, or water circulation in the two macrophytes.

5. Sida crystallina (Cladocera) collected from Trapa contained more haemoglobin than those collected from Vallisneria.

6. The replacement of Vallisneria by Trapa in the Hudson probably increased system‐wide biodiversity and food for fish, although macroinvertebrates in Trapa beds may not be readily available to fish because of low oxygen concentration there.
Phosphorus cycling and partitioning in an oligotrophic Everglades wetland ecosystem: a radioisotope tracing study
Authors: Noe Gregory B. , Scinto Leonard J. , Taylor Jonathan , Childers Daniel L. , Jones Ronald D.
Published: October 2003

1. Our goal was to quantify short‐term phosphorus (P) partitioning and identify the ecosystem components important to P cycling in wetland ecosystems. To do this, we added P radiotracer to oligotrophic, P‐limited Everglades marshes. 32PO4 was added to the water column in six 1‐m2 enclosed mesocosms located in long‐hydroperiod marshes of Shark River Slough, Everglades National Park. Ecosystem components were then repeatedly sampled over 18 days.

2. Water column particulates (>0.45 μm) incorporated radiotracer within the first minute after dosing and stored 95–99% of total water column 32P activity throughout the study. Soluble (<0.45 μm) 32P in the water column, in contrast, was always <5% of the 32P in surface water. Periphyton, both floating and attached to emergent macrophytes, had the highest specific activity of 32P (Bq g−131P) among the different ecosystem components. Fish and aquatic macroinvertebrates also had high affinity for P, whereas emergent macrophytes, soil and flocculent detrital organic matter (floc) had the lowest specific activities of radiotracer.

3. Within the calcareous, floating periphyton mats, 81% of the initial 32P uptake was associated with Ca, but most of this 32P entered and remained within the organic pool (Ca‐associated = 14% of total) after 1 day. In the floc layer, 32P rapidly entered the microbial pool and the labile fraction was negligible for most of the study.

4. Budgeting of the radiotracer indicated that 32P moved from particulates in the water column to periphyton and floc and then to the floc and soil over the course of the 18 day incubations. Floc (35% of total) and soil (27%) dominated 32P storage after 18 days, with floating periphyton (12%) and surface water (10%) holding smaller proportions of total ecosystem 32P.

5. To summarise, oligotrophic Everglades marshes exhibited rapid uptake and retention of labile 32P. Components dominated by microbes appear to control short‐term P cycling in this oligotrophic ecosystem.
Review of competing hypotheses of phylogenetic relationships of Paussinae (Coleoptera: Carabidae) based on larval characters
Authors: Di Giulio Andrea , Fattorini Simone , Kaupp Andreas , Taglianti Augusto Vigna , Nagel Peter
Published: October 2003

Abstract. Larval structural characters are an important component in phylogenetic reconstruction of the subfamily Paussinae. Based on larval characters, two main cladistic hypotheses have been proposed concerning basal relationships within Paussinae: (1) Metriini as sister‐group of Ozaenini + Paussini, with Ozaenini as a paraphyletic group and the genusPhyseaas sister‐group of Paussini; and (2) Metriini as sister‐group only of the monophyletic Ozaenini, with the Paussini as sister‐group of Metriini + Ozaenini. We present here a review of these hypotheses and a new cladistic analysis based on larvae, emphasizing the phylogeny of Ozaenini. The analysis includes the following taxa:Metrius(Metriini),Itamus,Pachyteles,Sphaerostylus,Physea(Ozaenini),PlatyrhopalopsisandPaussus(Paussini). For bothPhyseaandPlatyropalopsislarvae we provide new detailed descriptions, because previous descriptions are inadequate to allow an advanced phylogenetic discussion. A total of fifty‐six characters are analysed. Most characters show alternative states organized into sequences of character states, each of which is logically derivable from its neighbour in the sequence, resulting in an almost completely pectinate cladogram.Metriusis the sister‐group of all other Paussinae, and Paussini are a highly derived offshoot within the ozaenine grade. According to the present analysis,Physea, regarded traditionally as a typical ozaenine, represents the ozeanine sister to Paussini, showing that Ozaenini are paraphyletic. As our analysis is based on the few paussine genera sufficiently known at the larval stage, which represent a low number of the extant paussine genera, the results are merely illustrative of the evolution of the major clades within the subfamily. More detailed information about the phylogeny of ozaenines could arise from a more comprehensive analysis, mainly including adult morphological characters.
Mutational analysis of arginine 177 in the nucleotide binding site of β‐actin
Authors: Schüler Herwig , Nyåkern Maria , Schutt Clarence E. , Lindberg Uno , Karlsson Roger
Published: October 2003

Actin ADP‐ribosylated at arginine 177 is unable to hydrolyze ATP, and the R177 side chain is in a position similar to that of the catalytically essential lysine 71 in heat shock cognate protein Hsc70, another member of the actin‐fold family of proteins. Therefore, actin residue R177 has been implicated in the mechanism of ATP hydrolysis. This paper compares wild‐type β‐actin with a mutant in which R177 has been replaced by aspartic acid. The mutant β‐actin was expressed in Saccharomyces cerevisiae and purified by DNase I‐affinity chromatography. The mutant protein exhibited a reduced thermal stability and an increased nucleotide exchange rate, suggesting a weakened interdomain connection. The ATPase activity of G‐actin and the ATPase activity expressed during polymerization were unaffected by the R177D replacement, showing that this residue is not involved in catalysis. In the presence of polymerizing salts, ATP hydrolysis by both wild‐type Mg‐β‐actin and the mutant protein preceded filament formation. With the mutant actin, the initial rate of ATP hydrolysis was as high as with wild‐type actin, but polymer formation was slower, reached lower steady‐state levels, and the polymers formed exhibited much lower viscosity. The critical concentration of polymerization (Acc) of the mutant actin was increased 10‐fold as compared to wild‐type actin. Filaments formed from the R177D mutant β‐actin bound phalloidin.
Overproduction of Thermus sp. YS 8‐13 manganese catalase in Escherichia coli
Authors: Mizobata Tomohiro , Kagawa Masayuki , Murakoshi Noriyuki , Kusaka Eiko , Kameo Kazunori , Kawata Yasushi , Nagai Jun
Published: October 2003

Overproduction of Thermus sp. YS 8‐13 manganese catalase in Escherichia coli BL21(DE3) was accomplished by introducing a derivative of pET‐23a(+) containing a copy of the coding gene into the multicloning site. E. coli BL21(DE3)/pETMNCAT produced abundant quantities of manganese catalase as insoluble inclusion bodies. Regeneration of active catalase was achieved by denaturation in guanidine hydrochloride and subsequent dialysis in the presence of manganese ion. When the E. coli chaperone genes GroEL, GroES, DnaK, DnaJ and GrpE were coexpressed with manganese catalase, a significant fraction of the overproduced protein was partitioned into the soluble fraction. However, almost all of the soluble enzyme was isolated in a manganese‐deficient apo form which could subsequently be converted into active holoenzyme by incubation with manganese ion at high temperatures. Further experiments on this apo catalase suggested that the structure of this protein was virtually identical to the active holoenzyme.
Interaction of fMet‐tRNAfMetand fMet‐AMP with the C‐terminal domain ofThermus thermophilustranslation initiation factor 2
Authors: Szkaradkiewicz Karol , Zuleeg Tilman , Limmer Stefan , Sprinzl Mathias
Published: October 2003

Two polypeptides resistant against proteolytic digestion were identified inThermus thermophilustranslation initiation factor 2 (IF2): the central part of the protein (domains II/III), and the C‐terminal domain (domain IV). The interaction of intact IF2 and the isolated proteolytic fragments with fMet‐tRNAfMetwas subsequently characterized. The isolated C‐terminal domain was as effective in binding of the 3′ end of fMet‐tRNAf Metas intact IF2. N‐Formylation of Met‐tRNAfMetwas required for its efficient binding to the C‐terminal domain. This suggests that the interaction between the C‐terminal domain and the 3′ end of fMet‐tRNAfMetis responsible for the recognition of fMet‐tRNAfMetby IF2 during translation initiation. Moreover, it was demonstrated that fMet‐AMP is a minimal ligand of IF2. fMet‐AMP inhibits fMet‐tRNAfMetbinding to IF2 as well as the activity of IF2 in the stimulation of ApUpG‐dependent ribosomal binding of fMet‐tRNAf Met. Specific interaction of fMet‐AMP with IF2 was demonstrated by1H‐NMR spectroscopy.

These findings indicate that fMet‐AMP and the 3′ terminal fMet‐adenosine of fMet‐tRNAfMetuse the same binding site on the C‐terminal domain of IF2 and imply that the interaction between the C‐terminal domain and the 3′ end of fMet‐tRNAfMetis primarily responsible for the fMet‐tRNAfMetbinding and recognition by IF2.
Large‐scale expression and thermodynamic characterization of a glutamate receptor agonist‐binding domain
Authors: Madden Dean R. , Abele Rupert , Andersson Arnold , Keinänen Kari
Published: October 2003

The ionotropic glutamate receptors (GluR) are the primary mediators of excitatory synaptic transmission in the brain. GluR agonist binding has been localized to an extracellular domain whose core is homologous to the bacterial periplasmic binding proteins (PBP). We have established routine, baculovirus‐mediated expression of a complete ligand‐binding domain construct at the 10‐L scale, yielding 10–40 milligrams of purified protein. This construct contains peptides that lie outside the PBP‐homologous core and that connect the domain core to the transmembrane domains of the channel and to the N‐terminal ‘X’‐domain. These linker peptides have been implicated in modulating channel physiology. Such extended constructs have proven difficult to express in bacteria, but the protein described here is stable and monomeric. Isothermal titration calorimetry reveals that glutamate binding to the domain involves a substantial heat capacity change and that at physiological temperatures, the reaction is both entropically and enthalpically favorable.
Effect of growth temperature on cellular fatty acids in sulphate‐reducing bacteria
Authors: Könneke Martin , Widdel Friedrich
Published: October 2003

The effect of growth temperature on the cellular fatty acid composition of sulphate‐reducing bacteria (SRB) was studied in 12 species belonging to eight genera including psychrophiles and mesophiles. Most of these species were of marine origin. The investigated SRB with the exception of four Desulfobacter species exhibited only a minor increase in the proportion of cis‐unsaturated fatty acids (by ≤5% per 10°C) when the growth temperature was decreased; psychrophiles maintained their typically high content of cis‐unsaturated fatty acids (around 75% of total fatty acids) nearly constant. The four Desulfobacter species, however, increased the proportion of cis‐unsaturated among total fatty acids significantly (by ≥14% per 10°C; measured in late growth phase) with decreasing growth temperature. The ratio between unsaturated and saturated fatty acids in Desulfobacter species changed not only with the growth temperature, but also with the growth state in batch cultures at constant temperature. Changes of cellular fatty acids were studied in detail with D. hydrogenophilus, the most psychrotolerant (growth range 0–35°C) among the mesophilic SRB examined. Desulfobacter hydrogenophilus also formed cis‐9,10‐methylenehexadecanoic acid (a cyclopropane fatty acid) and 10‐methylhexadecanoic acid. At low growth temperature (12°C), the relative amount of these fatty acids was at least threefold lower; this questions the usefulness of 10‐methylhexadecanoic acid as a reliable biomarker of Desulfobacter in cold sediments.
Indigenous and contaminant microbes in ultradeep mines
Authors: Onstott T. C. , Moser D. P. , Pfiffner S. M. , Fredrickson J. K. , Brockman F. J. , Phelps T. J. , White D. C. , Peacock A. , Balkwill D. , Hoover R. , Krumholz L. R. , Borscik M. , Kieft T. L. , Wilson R.
Published: October 2003

Rock, air and service water samples were collected for microbial analyses from 3.2 kilometres depth in a working Au mine in the Witwatersrand basin, South Africa. The ∼ metre‐wide mined zone was comprised of a carbonaceous, quartz, sulphide, uraninite and Au bearing layer, called the Carbon Leader, sandwiched by quartzite and conglomerate. The microbial community in the service water was dominated by mesophilic aerobic and anaerobic, α‐, β‐ and γ‐Proteobacteria with a total biomass concentration ∼104 cells ml−1, whereas, that of the mine air was dominated by members of the Chlorobi and Bacteroidetes groups and a fungal component. The microorganisms in the Carbon Leader were predominantly mesophilic, aerobic heterotrophic, nitrate reducing and methylotrophic, β‐ and γ‐Proteobacteria that were more closely related to service water microorganisms than to air microbes. Rhodamine WT dye and fluorescent microspheres employed as contaminant tracers, however, indicated that service water contamination of most of the rock samples was < 0.01% during acquisition. The microbial contaminants most likely originated from the service water, infiltrated the low permeability rock through and accumulated within mining‐induced fractures where they survived for several days before being mined. Combined PLFA and terminal restriction fragment length profile (T‐RFLP) analyses suggest that the maximum concentration of indigenous microorganisms in the Carbon Leader was < 102 cells g−1. PLFA, 35S autoradiography and enrichments suggest that the adjacent quartzite was less contaminated and contained ∼103 cells gram−1 of thermophilic, sulphate reducing bacteria, SRB, some of which are δ‐Proteobacteria. Pore water and rock geochemical analyses suggest that these SRB′s may have been sustained by sulphate diffusing from the adjacent U‐rich, Carbon Leader where it was formed by radiolysis of sulphide.
Distribution of chloropigments in suspended particulate matter and benthic microbial mat of a meromictic lake, Lake Kaiike, Japan
Authors: Nakajima Yoji , Okada Hisatake , Oguri Kazumasa , Suga Hisami , Kitazato Hiroshi , Koizumi Yoshikazu , Fukui Manabu , Ohkouchi Naohiko
Published: October 2003

We investigated the distribution of chloropigments in a small meromictic lake, Lake Kaiike, south‐west Japan. In the water‐column, concentrations of Chl a related to cyanobacteria, BChl a related to purple sulphur bacteria, and three types of BChl e homologues (BChls e1, e2 and e3) related to brown‐coloured green sulphur bacteria, were maximal at the redox boundary. Below the redox boundary, absolute concentrations of Chl a and BChl a gradually decreased with depth, whereas BChls e remained rather constant. Suspended particulate matter (SPM) at the deeper region of the anoxic water‐column was enriched in highly alkylated BChl e homologues compared with SPM at the redox boundary. The shift in the relative content of highly alkylated BChl e homologues beneath the boundary was associated with community related adaptation of brown‐coloured green sulphur bacteria to changes in light quality/quantity, resulting from the optical absorption and reflectance of SPMs in the overlying water‐column. Benthic microbial mats were characterized by high abundances of BChls e, in which highly alkylated homologues were substantially abundant. This suggests that the BChls e in the microbial mat may be derived from the low‐light adapted brown‐coloured green sulphur bacteria forming the bacterial mat.
Vulval lymphangiomata mimicking genital warts
Authors: Al Aboud K , Al Hawsawi K , Ramesh V , Al Aboud D , Al Githami A
Published: October 2003

Genital warts can mimic a variety of conditions. We report a middle‐aged pregnant woman with lymphangiectatic lesions on the vulva resembling warts.
Serum Vitamin D and Falls in Older Women in Residential Care in Australia
Authors: Flicker Leon , Mead Kate , MacInnis Robert J. , Nowson Caryl , Scherer Sam , Stein Mark S. , Thomasx Jennifer , Hopper John L. , Wark John D.
Published: October 2003

Objectives: To determine the prevalence of vitamin D deficiency in older people in residential care and the influence that the level of vitamin D may have on their incidence of falls.

Design: Prospective cohort.

Setting: Residential care facilities for older people in several states of Australia.

Participants: Six hundred sixty‐seven women in low‐level care and 952 women in high‐level care, mean age 83.7 years.

Measurements: Serum 25‐hydroxyvitamin D (25D) levels and recognized risk factors for falls including current medication use, a history of previous fractures, weight, tibial length (as a surrogate for height), cognitive function, walking ability, and frequency of going outdoors were determined. The women in low‐level care and high‐level care were followed for an average of 145 and 168 days, respectively. Falls were recorded prospectively in diaries completed monthly by residential care staff.

Results: Vitamin D deficiency (defined as a serum 25D level below 25 nmol/L) was present in 144 (22%) women in low‐level care and 428 (45%) in high‐level care. After excluding 358 bed‐bound residents and adjusting for weight, cognitive status, psychotropic drug use, previous Colles fracture, and the presence of wandering behavior, log serum 25D level remained independently associated with time to first fall. The adjusted hazards ratio was 0.74 (95% confidence interval=0.59–0.94; P=.01), implying a 20% reduction in the risk of falling with a doubling of the vitamin D level.

Conclusion: Vitamin D deficiency is common in residential care in Australia. A low level of serum vitamin D is an independent predictor of incident falls.
RBC alloimmunization and autoimmunization among transfusion‐dependent Arab thalassemia patients
Authors: Ameen Reem , Al‐Shemmari Salem , Al‐Humood Salah , Chowdhury Rafiq I. , Al‐Eyaadi Ohood , Al‐Bashir Abdulaziz
Published: October 2003

BACKGROUND:  Thalassemia major is a common hemoglobinopathy in the Arabian Gulf region. However, limited data are available on the frequency of RBC alloimmunization and autoimmunization in transfusion‐dependent Arab thalassemia patients.

STUDY DESIGN AND METHODS:  A total of 190 thalassemia major patients were classified as Kuwaiti Arab and non‐Kuwaiti Arab. Pretransfusion investigation records were reviewed for the presence of RBC alloantibody and autoantibody, and the age at which RBC alloantibody was developed.

RESULTS:  Fifty‐seven (30%) patients developed RBC alloantibodies. The most common clinically significant alloantibodies were directed against antigens in the Kell and Rh systems. Anti‐K developed in 41 (72%) patients followed by anti‐E in 26 (45.6%). RBC autoantibodies developed in 21 (11%) patients with and without underlying RBC alloantibodies. Sixty‐six (49.6%) RBC alloantibodies developed between the ages of 2 and 10 years.

CONCLUSION:  Several factors might have contributed to the high alloimmunization and autoimmunization rate observed in this study, including the heterogeneity of the population living in Kuwait, lack of better‐matched donors for those patients, and the use of poststorage leukodepleted blood. It is recommended that thalassemia patients receive blood matched for Rh and Kell antigens and prestorage leukodepleted RBCs.
Weakening or loss of antibody reactivity after prewarm technique
Authors: Leger Regina M. , Garratty George
Published: October 2003

BACKGROUND:  The prewarm (PW) technique is a popular approach to determine whether cold antibodies are reacting at 37°C or to detect potentially clinically significant antibodies in the presence of cold autoantibodies. The PW technique has been criticized because of unexpected loss of antibody reactivity and inappropriate use of the method.

STUDY DESIGN AND METHODS:  Sera containing 94 antibodies were tested by routine and PW PBS‐, LISS‐, and PEG‐IAT. LISS‐IAT was also compared to PW PBS‐IAT. Sera were also tested to determine the role of low‐affinity antibodies in loss of reactivity by PW methods.

RESULTS:  PW PBS‐IAT and PW LISS‐IAT showed that 40 and 47 percent of antibodies were weakened, respectively, compared to LISS‐IAT; reactivity for 14 percent of antibodies was completely lost by each PW method. By PW PBS‐IAT, 34 percent of antibodies were weakened compared to PBS‐IAT. PW PEG‐IAT showed weakened reactivity by 56 percent of antibodies compared to PEG‐IAT; reactivity of seven out of seven PEG‐dependent antibodies was completely lost. Of 67 antibodies, 19 percent were defined as low affinity. Of 64 samples tested by the PW method and for low‐affinity antibodies, only 6 of 30 that showed decreased reactivity by the PW method appeared to be due to low‐affinity antibodies; only 6 of 12 samples that appeared to contain low‐affinity antibodies also showed decreased reactivity by the PW method.

CONCLUSION:  Antibody reactivity of potentially clinically significant antibodies can be decreased or missed by PW methods. Antibody enhancement media does not ensure antibody detection by PW methods.
The matrix protein pp65341‐350: a peptide that induces ex vivo stimulation and in vitro expansion of CMV‐specific CD8+ T cells in subjects bearing either HLA‐A*2402 or A*0101 allele
Authors: Provenzano Maurizio , Lim Jong‐Baeck , Mocellin Simone , Monsurro Vladia , Bettinotti Maria , Marincola Francesco M. , Stroncek David F.
Published: October 2003

BACKGROUND:  The stimulation of PBMNCs with HLA Class I restricted synthetic peptides derived from CMV phosphorylated matrix protein 65 (pp65) evokes CMV‐specific cytotoxic T lymphocyte (CTL) activity, a necessary condition for initiating adoptive immunotherapy against CMV‐related diseases in immune‐compromised patients. It was previously demonstrated that the CMV decamer (10‐mer) peptide pp65341‐350, QYDPVAALFF, was able to induce CMV‐specific CTLs in HLA‐A*2402 CMV‐seropositive individuals.

STUDY DESIGN AND METHOD:  We investigated the ability of the peptide pp65341‐350 to reactivate memory CD8+ T cells in CMV‐seropositive subjects bearing either the HLA‐A24 or A1 allele. CTL responses were measured by IFN‐γ mRNA expression and IFN‐γ protein production as well as cytotoxic activity.

RESULTS:  In this study it was found that peptide pp65341‐350 induced a specific reactivation of memory CD8+ T cells from CMV‐seropositive donors expressing either HLA‐A*2402 and/or HLA‐A*0101. Moreover, a pp65341‐350‐specific selection and expansion using PBMNCs of CMV‐seropositive donors bearing both HLA‐A*2402 and HLA‐A*0101 alleles produced cytotoxic CTLs to both HLA‐A24 and A1 peptide‐pulsed and autologous CMV‐infected target cells.

CONCLUSION:  The results demonstrate that pp65341‐350 induced a specific CTL activity at both molecular and protein levels and that the peptide is specifically processed, presented, and recognized by subjects bearing HLA‐A*2402 and/or A*0101. These findings suggest that it may be possible to use this single immune dominant peptide to induce and expand CMV‐reactive CTLs for the treatment of individuals with both HLA‐A24 and A1 types.
The fourth Painlevé equation and associated special polynomials
Authors: Clarkson Peter A.
Published: October 2003

In this article rational solutions and associated polynomials for the fourth Painlevé equation are studied. These rational solutions of the fourth Painlevé equation are expressible as the logarithmic derivative of special polynomials, the Okamoto polynomials. The structure of the roots of these Okamoto polynomials is studied and it is shown that these have a highly regular structure. The properties of the Okamoto polynomials are compared and contrasted with those of classical orthogonal polynomials. Further representations are given of the associated rational solutions in the form of determinants through Schur functions.
Ground-state potential energy curves of LiHg, NaHg, and KHg revisited
Authors: Thiel Linda , Hotop Hartmut , Meyer Wilfried
Published: October 2003

We present the results of large-scale CCSD(T) calculations on the potential energy curves for the ground states of LiHg, NaHg, and KHg. In these calculations, the Hg20+ core is simulated by a pseudopotential which has been adjusted to reproduce experimental excitation and ionization energies of the Hg atom at the coupled-cluster level. Moreover, we apply a weighted multiproperty fitting procedure to determine reliable potentials for LiHg, NaHg, and KHg which reproduce the available experimental results. In the case of LiHg, this best-fit potential is based solely on experimental data and its agreement with our calculated potential supports our computational procedure. For NaHg and KHg the experimental data had to be complemented by theoretical results in order to fix a best-fit potential. Our potentials and those proposed previously are evaluated by comparing calculated scattering cross sections and vibrational energy levels with the available experimental data.
Unusual luminescence lines in GaN
Authors: Reshchikov M. A. , Huang D. , Yun F. , Visconti P. , He L. , Morkoç H. , Jasinski J. , Liliental-Weber Z. , Molnar R. J. , Park S. S. , Lee K. Y.
Published: October 2003

A series of sharp intense peaks was observed in the low-temperature photoluminescence spectrum of unintentionally doped GaN in the photon energy range between 3.0 and 3.46 eV. We attributed the majority of these peaks to excitons bound to unidentified structural and surface defects. Most of the structural- and surface-related peaks (at 3.21, 3.32, 3.34, 3.35, 3.38, and 3.42 eV) were observed in Ga polar films. In N polar GaN, we often observed the 3.45 eV peak attributed to excitons bound to the inversion domain interfaces.
Symmetries of the energy–momentum tensor of spherically symmetric Lorentzian manifolds
Authors: Sharif M.
Published: October 2003

Matter collineations of spherically symmetric Lorentzian manifolds are considered. These are investigated when the energy–momentum tensor is nondegenerate and also when it is degenerate. We have classified space–times admitting higher symmetries and space–times admitting SO(3) as the maximal isometry group. For the nondegenerate case, we obtain either four, six, seven, or ten independent matter collineations in which four are isometries and the rest are proper. The results of the previous paper [Sharif and Sehar (Gen. Relativ. Gravit. 35, 1091 (2003)] are recovered as a special case. It is worth noting that we have also obtained two cases where the energy–momentum tensor is degenerate but the group of matter collineations is finite-dimensional, i.e., four or ten.
Dose dependence of formation of nanoscale cavities in helium-implanted 4H–SiC
Authors: Zhang C. H. , Donnelly S. E. , Vishnyakov V. M. , Evans J. H.
Published: October 2003

A cross-sectional transmission electron microscope investigation of dose dependence and annealing behavior of microstructures in helium-implanted silicon carbide is presented. Specimens of silicon carbide (4H–SiC) were mainly implanted with 30-keV-He ions at intermediate temperatures of 500 and 873 K to doses ranging from 5×1015 to 2×1017 cm−2, and subsequently annealed at temperatures up to 1173 K. For comparison other specimens were implanted at 293 K up to 5×1015 cm−2 and subsequently annealed. Three dose regimes of microstructural evolution were found, each of them exhibiting quite different annealing behavior. No cavities were found at the low dose range below 3.5×1016 cm−2. At intermediate doses of (3.5–5)×1016 cm−2, a low density of planar clusters of bubbles located in the basal plane was found in a well defined region around the damage peak on annealing above 973 K. After implantation to the high dose of 1017 cm−2, a high density of bubbles in alignment in the basal plane was formed, and remained stable during the subsequent annealing at temperatures up to 1173 K. The difference in annealing behavior suggests that helium is trapped with different energies for the three dose regimes. There appears to be a threshold dose for the formation of the bubble clusters of approximately 5×1015 cm−2 for implantation at room temperature. This increases to a value between 2×1016 and 5×1016 cm−2 for implantation at 500 and 873 K, respectively. Such a temperature dependence is consistent with that of effective damage production, indicating a certain level of damage is necessary for the formation of bubble clusters. The formation of planar clusters of bubbles at the intermediate doses is ascribed to an Ostwald ripening (OR) process through the dissociation of the simple He/vacancy clusters and metastable bubbles and the formation of planar cavities of helium on annealing above 973 K.
A Grassmann integral equation
Authors: Scharnhorst K.
Published: October 2003

The present study introduces and investigates a new type of equation which is called Grassmann integral equation in analogy to integral equations studied in real analysis. A Grassmann integral equation is an equation which involves Grassmann (Berezin) integrations and which is to be obeyed by an unknown function over a (finite-dimensional) Grassmann algebra Gm (i.e., a sought after element of the Grassmann algebra Gm). A particular type of Grassmann integral equations is explicitly studied for certain low-dimensional Grassmann algebras. The choice of the equation under investigation is motivated by the effective action formalism of (lattice) quantum field theory. In a very general setting, for the Grassmann algebras G2n, n=2,3,4, the finite-dimensional analogues of the generating functionals of the Green functions are worked out explicitly by solving a coupled system of nonlinear matrix equations. Finally, by imposing the condition G[{Ψ̄},{Ψ}]=G0[{λΨ̄},{λΨ}]+const, 0<λ∈R (Ψ̄k, Ψk, k=1,…,n, are the generators of the Grassmann algebra G2n), between the finite-dimensional analogues G0 and G of the (“classical”) action and effective action functionals, respectively, a special Grassmann integral equation is being established and solved which also is equivalent to a coupled system of nonlinear matrix equations. If λ≠1, solutions to this Grassmann integral equation exist for n=2 (and consequently, also for any even value of n, specifically, for n=4) but not for n=3. If λ=1, the considered Grassmann integral equation (of course) has always a solution which corresponds to a Gaussian integral, but remarkably in the case n=4 a further solution is found which corresponds to a non-Gaussian integral. The investigation sheds light on the structures to be met for Grassmann algebras G2n with arbitrarily chosen n.
On the calculation of vibrational energy relaxation rate constants from centroid molecular dynamics simulations
Authors: Shi Qiang , Geva Eitan
Published: October 2003

We explore the use of centroid molecular dynamics (CMD) for calculating vibrational energy relaxation (VER) rate constants of high-frequency molecular vibrations in the condensed phase. We employ our recently proposed linear-response-theory-based approach to VER [Q. Shi and E. Geva, J. Chem. Phys. 118, 7562 (2003)], to obtain a new expression for the VER rate constant in terms of a correlation function that can be directly obtained from CMD simulations. We show that the new expression reduces to a centroid Landau-Teller-type formula in the golden-rule regime. Unlike previously proposed CMD-based approaches to VER, the new formula does not involve additional assumptions beyond the inherent CMD approximation. The new formula has the same form as the classical Landau–Teller formula, and quantum effects enter it in two ways: (1) The initial sampling and subsequent dynamics are governed by the centroid potential, rather than the classical potential; (2) The classical force is replaced by the corresponding centroid symbol. The application of the new method is reported for three model systems: (1) A vibrational mode coupled to a harmonic bath, with the coupling exponential in the bath coordinates; (2) A diatomic molecule coupled to a short linear chain of Helium atoms; (3) A “breathing sphere” diatomic molecule in a two-dimensional monoatomic Lennard-Jones liquid. It is confirmed that CMD is able to capture the main features of the force–force correlation function rather well, in both time and frequency domains. However, we also find that CMD is unable to accurately predict the high-frequency tail of the quantum-mechanical power spectrum of this correlation function, which limits its usefulness for calculating VER rate constants of high-frequency molecular vibrations. The predictions of CMD are compared with those obtained via the linearized-semiclassical initial-value-representation (LSC-IVR) method, which does yield accurate predictions of high-frequency VER rate constants. The reasons underlying these observations are discussed in terms of the similarities and differences between these two approaches.
Degradation of radiatively driven inertial confinement fusion capsule implosions by multifluid interpenetration mixing
Authors: Wilson D. C. , Scannapieco A. J. , Cranfill C. W. , Clover M. R. , Hoffman N. M. , Collins J.
Published: October 2003

The observed degradation of radiatively driven single shell capsule yield with increasing convergence ratio can be quantitatively understood by mixing between the gaseous deuterium-tritium (DT) or deuterium (DD) and the pusher. Calculations using a multifluid interpenetration mix model can replicate the performance of experiments at the NOVA [C. Bibeau et al., Appl. Opt. 31, 5799 (1992)] and OMEGA [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] lasers, using a single fitting parameter, a mixing length ratio. When mix is similarly treated at the ablator–solid DT interface, cryogenic single shell ignition capsules for the National Ignition Facility [J. A. Paisner, E. M. Campbell, and W. J. Hogan, Fusion Technol. 26, 755 (1994)] and the Laser Mega Joule [ P. A. Holstein et al., Laser Part. Beams 17, 403 (1999)] calculate to ignite and burn with gains of several due to isolation of the ignition hot spot from the pusher material.
Limiting current in a relativistic diode under the condition of magnetic insulation
Authors: Lopez Mike , Lau Y. Y. , Luginsland John W. , Jordan David W. , Gilgenbach Ronald M.
Published: October 2003

The maximum emission current density is calculated for a time-independent, relativistic, cycloidal electron flow in a diode that is under the condition of magnetic insulation. Contrary to conventional thinking, this maximum current is not determined by the space charge limited condition on the cathode, even when the emission velocity of the electrons is assumed to be zero. The self electric and magnetic fields associated with the cycloidal flow are completely accounted for. This maximum current density is confirmed by a two-dimensional, fully electromagnetic and fully relativistic particle-in-cell code.
Changes in the dominant recombination mechanisms of polycrystalline Cu(In,Ga)Se2 occurring during growth
Authors: Keyes B. M. , Dippo P. , Metzger W. K. , AbuShama J. , Noufi R.
Published: October 2003

The changes in dominant recombination mechanisms of Cu(In,Ga)Se2 thin films grown from (In,Ga)2Se3 precursors are investigated using energy- and time-resolved photoluminescence. The results are analyzed with a rate-equation analysis and correlated with n/p diode measurements on processed devices. The experimental results quantify a change in the dominant radiative process and an improvement in the underlying material quality. These observations support a growth model incorporating changes in the dominant defect states and recombination mechanisms during this final stage of the growth process. Additionally, evidence is presented that supports the passivation of near-surface recombination sites by CdS.