bluuebunny/crossref_metadata_2025 huggingface dataset:
Taxonomy and origin of present-day morphometric variation inPicea glauca(×engelmannii) seed-cone scales in North America
Authors: Strong W.L , Hills L.V.
Published: September 2006

White spruce ( Picea glauca (Moench) Voss) and Engelmann spruce ( Picea engelmannii Parry ex Engelm.) seed-cones from 676 sites in Canada and the northern United States were analyzed to determine the degree and spatial extent of interspecific hybridization. Fifteen cone-scale variables were analyzed, with percent free-scale and scale shape considered best for differentiating these taxa. The results show that putative Engelmann spruce and their hybrids occur mostly in the vicinity of the Rocky Mountains. Putative white spruce occurs across Canada east of the Rocky Mountains, whereas white × Engelmann hybrids occur eastward to Manitoba and northward to 68° latitude in northwest Canada. To explain the occurrence of the latter taxon hundreds of kilometres from an Engelmann spruce pollen source, it is hypothesized that palaeohybridization occurred during the Wisconsinan glacial period, probably in the southern Montana – Wyoming – Black Hills (South Dakota) region, with the resulting hybrids spreading north and northeastward into interior Canada following the retreat of the Laurentide glacier. White and Engelmann spruce have morphologically distinct cone-scales, whereas their hybrids have intermediate characteristics. An emended species ( Picea albertiana ) and two subspecies (P. albertiana subsp. albertiana and P. albertiana subsp. ogilviei) are proposed to account for morphological intermediates between the parent species.
Length–biomass allometry in primary producers: predominantly bidimensional seaweeds differ from the “universal” interspecific trend defined by microalgae and vascular plants
Authors: Scrosati Ricardo
Published: September 2006

This study tests whether the value (0.25, or 1/4) of the interspecific allometric exponent currently thought to be universal for the length–biomass relationship for primary producers (based on data for vascular plants and unicellular microalgae) also applies to macroalgae. Length and dry biomass were measured for four phylogenetically distinct seaweed species, Chondrus crispus Stackhouse, Pterocladiella capillacea (Gmelin) Santelices & Hommersand, Fucus vesiculosus Linnaeus, and Laminaria saccharina (Linnaeus) J.V. Lamouroux, which are representatives of four different orders: Gigartinales and Gelidiales (Rhodophyta) and Fucales and Laminariales (Phaeophyceae). The interspecific exponent found for these seaweeds (0.47) differs significantly from the interspecific “universal” value stated above. The 95% confidence interval for the interspecific exponent for these seaweeds includes 0.5 (or 1/2), a value that is related to an idealized form of bidimensional growth. While vascular plants and unicellular microalgae can be viewed as clearly growing in three dimensions, the studied seaweeds are predominantly flat, which thus seems to explain their divergent allometry. The present study indicates that the comprehensive understanding of allometric trends for primary producers should be based on studies covering the morphological diversity that different groups of primary producers display.
Isolates of endophytic Chaetomium spp. inhibit the fungal pathogen Pyrenophora tritici-repentis in vitro
Authors: Istifadah Noor , Saleeba Jennifer A. , McGee Peter A.
Published: September 2006

Growth of a culturable pathogen, Pyrenophora tritici-repentis (Died.) Drechs., was inhibited by six isolates of endophytic Chaetomium spp. in vitro when grown in apposition. Metabolites of the endophytes, when grown either on agar or in liquid media, also inhibited the pathogen. The culture filtrate of Chaetomium was extracted in 70% ethanol, and the ethanol-soluble fraction that either passed through a molecular sieve of 3000 molecular mass cutoff or was held on 30 000 molecular mass cutoff inhibited the pathogen. The high molecular mass fraction was a protein with one major band at 29 kDa. The electroeluted band delayed the growth of the pathogen in vitro. Inhibition was retained in filtrate stored frozen, as dried residue, and when rehydrated after drying. Autoclaving reduced, whereas proteinase K treatment did not affect, the activity of the proteinaceous fraction. The data support the hypothesis that endophytic Chaetomium produce a range of metabolites that inhibit P. tritici-repentis in vitro and may affect the pathogen when the fungi co-occur in wheat.
Genetic variation in fall cold hardiness in coastal Douglas-fir in western Oregon and Washington
Authors: St. Clair J. Bradley
Published: September 2006

Genetic variation in fall cold damage in coastal Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco var. menziesii ) was measured by exposing excised branches of seedlings from 666 source locations grown in a common garden to freezing temperatures in a programmable freezer. Considerable variation was found among populations in fall cold hardiness of stems, needles, and buds compared with bud burst, bud set, and biomass growth after 2 years. Variation in fall cold hardiness was strongly correlated (r = 0.67) with cold-season temperatures of the source environment. Large population differences corresponding with environmental gradients are evidence that natural selection has been important in determining genetic variation in fall cold hardiness, much more so than in traits of bud burst (a surrogate for spring cold hardiness), bud set, and growth. Seed movement guidelines and breeding zones may be more restrictive when considering genetic variation in fall cold hardiness compared with growth, phenology, or spring cold hardiness. A regional stratification system based on ecoregions with latitudinal and elevational divisions, and roughly corresponding with breeding zones used in Oregon and Washington, appeared to be adequate for minimizing population differences within regions for growth and phenology, but perhaps not fall cold hardiness. Although cold hardiness varied among populations, within-population and within-region variation is sufficiently large that responses to natural or artificial selection may be readily achieved.
Arbuscular mycorrhizae on Axel Heiberg Island (80°N) and at Saskatoon (52°N) Canada
Authors: Allen Nathan , Nordlander Mattias , McGonigle Terence , Basinger James , Kaminskyj Susan
Published: September 2006

Arbuscular mycorrhizae (AM) are seldom reported from high latitudes. We found that Asteraceae ( Arnica , Erigeron , and Taraxacum ) at a site on Axel Heiberg Island (approximately 80°N) have abundant AM and fine endophytes (FE). We used standard microscopic methods for examination and quantification, plus high-resolution confocal fluorescence imaging. AM in Arctic Asteraceae were compared with those in congeners from Saskatoon and with those in some other Arctic species. Arctic AM had 6 µm wide aseptate hyphae producing abundant arbuscules, vesicles, and inter- and intra-cellular hyphae. AM colonization exceeded 80% for Arctic Asteraceae, similar to 66%–90% for prairie Taraxacum and Erigeron, the first of this type of comparison. AM/FE abundance in Arctic Ranunculus was 68%. Within Taraxacum roots, hyphal coils predominated near the epidermis and arbuscules near the vascular cylinder. Arctic AM colonization did not vary with soil depth, although permafrost was approximately 15 cm below the surface. FE were abundant in our High Arctic samples, where they may have functional roles comparable with those of AM. Thus, low abundance of AM reported previously at the community level for high-latitude sites may reflect a combination of biotic and abiotic factors. The Axel Heiberg Island thermal oasis is ideal for functional fungal root endophyte studies in the High Arctic.
Possible roles for ethylene and gibberellin in the phenotypic plasticity of an alpine population of Stellaria longipes
Authors: Kurepin Leonid V. , Mancell Lisa , Reid David M. , Pharis Richard P. , Chinnappa C.C.
Published: September 2006

Four phenotypically different genotypes from an alpine population of Stellaria longipes Goldie s.l. (Caryophyllaceae) were collected from neighbouring sites at the top of the Plateau Mountain in southeastern Alberta, Canada, to examine a possible hormonal basis for their differences in stem length, leaf size, and flowering characteristics. All four genotypes had a dwarf shoot phenotype, compared with the low-elevation ecotype. Among the four genotypes, PMI-D was the tallest and had the largest leaves and flowers as well as more flowers per plant. PMI-D also maintained the flowering state, upon repropagation, without low temperature, short-day vernalization. Under controlled long-day warm conditions, the PMI-D genotype had a higher rate of ethylene evolution, but contained levels of endogenous gibberellin A1 that were similar to the other three (smaller) alpine genotypes. PMI-D was more sensitive to exogenously applied ethylene and growth-active gibberellins than other alpine genotypes. In contrast, the other three genotypes were smaller, had fewer (and smaller) flowers, and exhibited low ethylene evolution and a reduced sensitivity to applied ethylene and growth-active gibberellins. Speculatively, this behaviour may indicate an adaptation within this unique population of “dwarf” phenotypes that involves enhanced sensitivity to endogenous ethylene and gibberellins.
Remarques concernant l'étude des événements à quatre jets issus de la désintégration hadronique du Z0
Authors: Jeremie H , Leblanc P , Lefebvre E
Published: September 2006

The angular correlations of four-jet events from hadronic decays of the Z0 have been studied in the past mainly to extract from them the fundamental constants of quantum chromodynamics called colour factors. Previous studies have used all the available phase-space in order to maximize statistics. In this note we want to point out the possibility that significant differences between experiment and theory in restricted regions of phase space might have escaped detection. Such differences could be a harbinger of the existence of new particles. Some preliminary results are presented.
Mesure des propriétés diélectriques du béton par une large sonde coaxiale à terminaison ouverte
Authors: Filali Bilal , Rhazi Jamal-Eddine , Ballivy Gérard
Published: September 2006

We present nondestructive measurements of dielectric properties of concrete and mortar. The measures are made using a coaxial probe with a 32.5 mm open end, engineered specially for this work. The frequency domain goes from 100 to 900 MHz and includes frequently found frequencies in radars used for the auscultation of concrete structures. The probe was calibrated, and the measures were validated successfully on two solutions of different salinity, as well as on limestone and granite samples. Measures were also carried out on two mortars and six concretes of different recipes. We studied the effect of porosity and water content on the measures. The statistical analysis of the results indicates thatthe dispersion of measurements on these heterogeneous materials (granulometry from 5 to 20 nm) is comparable to that observed in limestone and granite. Our results confirm those from other authors who used more complicated techniques.[Traduit par la Rédaction]
Boundary-layer flow of a micropolar fluid on a continuous moving or fixed surface
Authors: Ishak Anuar , Nazar Roslinda , Pop Ioan
Published: September 2006

The present paper deals with the analysis of boundary-layer flow of a micropolar fluid on a fixed or continuous moving plane surface. Both parallel and reverse moving surfaces to the free stream are considered. The resulting system of nonlinear ordinary differential equations is solved numerically using the Keller-box method. Numerical results are obtained for skin friction coefficient, local Nusselt number, velocity, angular velocity, and temperature profiles. The results indicate that the effect of the material parameter on skin friction and heat transfer depends on the velocity ratio of the plate and the fluid.PACS No.: 47.15.Cb
Quantization on the circle
Authors: Merad M
Published: September 2006

We present, via the path-integral approach, the quantum study of a particle without spin constrained to move on a circle and subjected to the action of an external field (V, A). In the first stage, we follow the Faddeev–Senjanovic constraints technique that is essentially based on the Dirac algorithm; and in the second stage, we use the path-integral coherent state relative to the circle, compatible with the topological properties. In the two cases, the free particle and the problem of the magnetic field are shown as an illustrative calculation.PACS Nos.: 03.65–w, 03.65Ca, 03.65.Db
Root processes influencing phosphorus availability in volcanic soils under youngPinus radiataplantations
Authors: Liu Q , Loganathan P , Hedley M J , Skinner M F
Published: September 2006

Phosphorus (P) availability was investigated in rhizosphere soils under 4- to 5-year-old, second-rotation Pinus radiata D. Don and understorey grass (browntop, Agrostis capillaris L.) in two P-deficient Andosols (a Pumice Soil and an Allophanic Soil). Pinus radiata rhizosphere had more soil organic matter, greater mycorrhizal hyphal length density, higher acid phosphatase activity, and more concentrated dissolved organic carbon than bulk soil or the rhizosphere of grass species in one or both soils. Concentrations of resin P and organic P in the P. radiata rhizosphere were higher than those in the grass rhizosphere and bulk soils, suggesting that P. radiata rhizosphere processes have a greater potential to accumulate organic P and mobilize soil P than understorey grass rhizosphere processes. This effect was less marked in the Allophanic Soil than in the Pumice Soil, probably because of the higher P-fixing capacity and lower plant-available P concentrations in the Allophanic Soil.
Midrotation effects of biosolids application on tree growth and wood properties in aPinus radiataplantation
Authors: Wang Hailong , Kimberley Mark O , Magesan Guna N , McKinley Russell B , Lee John R , Lavery John M , Hodgkiss Pat DF , Payn Tim W , Wilks Peter J , Fisher Craig R , McConchie Don L
Published: September 2006

Biosolids have been applied to a 1000 ha Pinus radiata D. Don plantation in Nelson, New Zealand, since 1996. A research trial was established in a 6-year-old stand in 1997 with three stocking rates (300, 450, and 600 stems·ha–1), and biosolids were applied at ages 6, 9, and 12 years at three application rates based on total nitrogen loading at each application of 0 (control), 300 (standard), and 600 kg N·ha–1(high). The aim of this study was to evaluate the responses of tree growth rate and wood properties to biosolids application at midrotation. Since the trial was established, tree diameter and volume increment in the biosolids-treated plots have increased markedly. This increase in growth is being maintained at midrotation, with the year 13–14 volume increment being 40% greater in the standard treatment than the control, and 46% greater in the high treatment than the control. The response in growth has occurred across all stockings in the trial, although there has been a tendency for the difference in growth between the standard and high rates to be greater at higher stockings. A small but significant reduction of basic wood density and standing-tree sonic velocity in P. radiata was found in the biosolids treatments. Although the reductions in wood density and stiffness may slightly decrease the average log value in biosolids treated trees, this will be greatly outweighed by the large increase in wood volume.
Declines in soil-water nitrate in nitrogen-saturated watersheds
Authors: Edwards Pamela J , Williard Karl WJ
Published: September 2006

Two forested watersheds (WS3 and WS9) in the central Appalachians were artificially acidified with ammonium sulfate fertilizer. WS9 was treated for 8 years, whereas WS3 has been treated for approximately 15 years. Soil leachate was collected from a depth of 46 cm (B horizon) in WS9 and below the A, B, and C horizons in WS3. Nitrate concentrations from WS3 increased for approximately 10–12 years (depending upon horizon) and then did not increase from 2000 through 2003 despite continued fertilizer treatments. Nitrate concentrations in WS9 soil water increased for the first 3 years of fertilization, and then declined for another 2 years. After that time, the concentrations remained relatively constant at approximately 15 µequiv.·L–1; this period of low nitrate concentrations included 2.3 years of fertilization followed by 8.2 years of no fertilization. Stream-water nitrate concentrations from both watersheds indicate they were in stage 2 of nitrogen saturation; however, the soil-water nitrate behavior observed within the setting of continued elevated nitrogen inputs is at odds with responses predicted in current nitrogen saturation theory. We believe that the cessation of nitrate increases in at least the B and C horizons were due primarily to abiotic retention, with recalcitrant forms of dissolved organic carbon providing the carbon needed to induce retention. These results show that nitrogen cycling in forest soil ecosystems is more complex than current nitrogen saturation theory suggests.
Assessing the cumulative effects of postfire management on forest landscape dynamics in northeastern China
Authors: Wang Xugao , He Hong S , Li Xiuzhen , Hu Yuanman
Published: September 2006

We used the LANDIS model to study the long-term cumulative effects of postfire 10-year management (harvest and reforestation) on species abundance, age structure, and spatial pattern in the Tuqiang Forest Bureau on the northern slopes of the Great Hing'an Mountains after a catastrophic fire in 1987. Two simulation scenarios were constructed: the actual postfire management scenario and the natural regeneration scenario that assumed no postfire management activities occurred after the 1987 fire. Both scenarios were run with 10 replicated simulations per scenario over a 300-year period. Our results indicated that postfire management had a significant influence on species abundance, age structure, and spatial pattern. Postfire management effectively increased the abundance of coniferous trees (larch (Larix gmelinii) and Mongolian Scotch pine (Pinus sylvestris var. mongolica)), increased the abundance of white birch in the short-term simulation stage, and decreased the abundance of white birch (Betula platyphylla) in the long run. The aggregation level of white birch responded similarly to postfire management — increasing initially, and then decreasing over time. However, compared with the natural regeneration scenario, postfire management resulted in more fragmented larch and Mongolian Scotch pine, which could last for about 100–150 years because of timber harvesting in the first 10 years postfire. In addition, the age structure of larch forests under the postfire management scenario changed dramatically during the 300 simulation years: the abundance of mature and old-growth age classes of larch forests decreased dramatically in the first 10 years, but then increased and exceeded that under the natural regeneration scenario after about 100 simulation years. Therefore, although postfire management had a positive cumulative effect (less fragmented and more larch abundance) on forest recovery at the long-term successional stage, postfire management, especially timber harvesting within the first 10 years after the 1987 fire, posed negative effects (more fragmented and less mature forests) at short- and mid-term successional stages (about 100 years).
Modeling tree regeneration height growth after an experimental hurricane
Authors: Fajvan Mary Ann , Plotkin Audrey Barker , Foster David R
Published: September 2006

Annual height growth rates for six species of tree seedlings were modeled during the first 10 years of cohort initiation following an experimental hurricane in central Massachusetts. Selected canopy trees in a second-growth, transition oak – northern hardwoods forest were pulled over with a winch in a 50 m × 160 m area. Regeneration height growth did not follow the species-specific patterns anticipated if the disturbance had been stand replacing. Instead, the temporal increase in shade from crown expansion and sprouting of residual trees slowed cohort development and resulted in a variety of annual height growth patterns among species. Height development was followed separately for advance regeneration and new seedlings of red maple white ash, black cherry, black and yellow birch, paper birch, and red oak. All species had increasing height growth rates for 3 years followed by either decreasing or unchanged (flat) rates except red maple and ash advance regeneration, which had increasing rates throughout the measurement period. After 10 years, black and yellow birch, and red maple are the most numerous species and compose the majority of the tallest regeneration. Red oaks, which dominated the original stand, are few and unlikely to emerge to the canopy of the new cohort.
Unusual effect of controlling aboveground competition by Ledum groenlandicum on black spruce (Picea mariana) in boreal forested peatland
Authors: Lavoie Martin , Paré David , Bergeron Yves
Published: September 2006

Poor growth of black spruce (Picea mariana (Mill.) BSP) has been associated with the presence of Ledum groenlandicum L. (Ledum) on some sites in the eastern boreal forest in Canada. To increase black spruce productivity on lowland sites, a study was carried out to test the effect of mechanical control of Ledum (by clipping) on black spruce growth on forested peatland in northwestern Quebec. We compared the growth and foliar nutrient concentrations of advance-regeneration black spruce seedlings with and without Ledum control. Contrary to our expectations, our results showed that 3-year control of aboveground competition by Ledum decreased rather than increased black spruce growth and had no effect on foliar nutrient concentrations. Ledum grows on a variety of site types; therefore, the mere presence of this species does not necessarily indicate that there will be a problem with conifer regeneration (growth and germination).
Effects of release from suppression on wood functional characteristics in young Douglas-fir and western hemlock
Authors: Renninger Heidi J , Gartner Barbara L , Meinzer Frederick C
Published: September 2006

Little is known of wood properties in trees that were initially suppressed and subsequently released from suppression. The purpose of this study was to assess differences in growth ring width, specific conductivity (Ks), tracheid dimensions, moisture content, and wood density in suppressed Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and western hemlock (Tsuga heterophylla (Raf.) Sarg.) trees and trees released from suppression averaging 12–18 years of age. Growth ring width was 370% higher for Douglas-fir and 300% higher for western hemlock trees released from suppression, and Ks was 182% higher for Douglas-fir and 42% higher for western hemlock trees released from suppression. Earlywood width was approximately four times greater after release in both species, whereas the relative increase in latewood width was much greater in Douglas-fir. Tracheids were 25% wider and 11% longer in released Douglas-fir trees. In western hemlock, released trees had 19% wider tracheids that were approximately the same length as those in suppressed trees. Moisture content was 66% greater in released Douglas-fir and 41% greater in released western hemlock. Wood density decreased by 21% in Douglas-fir trees and by 11% in western hemlock trees released from suppression. However, wood density of released trees did not differ from average reported values, implying that wood from released trees may be suitable for many of its traditional applications.
ERROR ANALYSIS OF LATTICE BOLTZMANN BGK MODEL BASED ON EXTRAPOLATION TECHNIQUE
Authors: HAN SHAN-LING , LIN ZHONG-QIN , ZHU PING , LAI XIN-MIN
Published: September 2006

The lattice Boltzmann method, which can simulate the macroscopic behavior of fluid flow, is a relatively new approach. The error analysis of the lattice Boltzmann BGK model is proposed based on extrapolation technique. According to the Filippova procedure, the error estimation formula is derived. The theory analysis shows that the error of lattice Boltzmann method is proportional to the lattice size and the relaxation parameter. The non-equilibrium part of the distribution function leads to the main error. Finally, the proposed error analysis method is validated by numerical simulation of the lid-driven flows in a square cavity. The numerical results agree well with the theory analysis results.
THE POSSIBILITY OF MAGNETIC FIELD INDUCED SUPERCONDUCTIVITY IN COLOSSAL MAGNETORESISTIVE MANGANITES
Authors: KOO JE HUAN , CHO GUANGSUP
Published: September 2006

We investigate theoretically manganese oxides where the colossal magnetoresistance (CMR) is observed. It is found that CMR is dominated by the internal local field, Hi. In ferromagnetic states, field-induced superconductivity is possible in the case of large magnetic field to reduce Hi near zero.
TELEPORTATION WITHOUT JOINT MEASUREMENT IN CAVITY QED
Authors: XUE ZHENG-YUAN , YI YOU-MIN , CAO ZHUO-LIANG
Published: September 2006

Schemes for the teleporting of the cavity mode state and the unknown atomic state are proposed in cavity quantum electrodynamics (QED) without joint Bell-state measurement (BSM). The presented schemes are implemented with separate atomic measurements instead of any type of joint measurement. The discussion of the scheme indicates that it can be realized by current technologies.
INTERGRANULAR PROPERTIES OF Zr-SUBSTITUTED Y123 COMPOUNDS
Authors: SBÂRCIOG C. , REDAC R. T. , GR. DEAC I. , POP I.
Published: September 2006

AC susceptibility measurements have been done to determine the intergranular properties for some 123-superconducting ceramics. From the imaginary part of the complex susceptibility, χ″(T), the temperature dependence of the critical current density was determined by using Bean's model. The intergranular current density was experimentally determined from AC susceptibility data by varying the field amplitude. All intragrain critical parameters are gradually degraded with increasing the concentration of the dopant substituting on the rare-earth side and with decreasing the sintering temperature during the sample preparation.
SCALING PROPERTIES OF THE SPREAD HARMONIC MEASURES
Authors: GREBENKOV DENIS S.
Published: October 2006

A family of the spread harmonic measures is naturally generated by partially reflected Brownian motion. Their relation to the mixed boundary value problem makes them important to characterize the transfer capacity of irregular interfaces in Laplacian transport processes. This family presents a continuous transition between the harmonic measure (Dirichlet condition) and the Hausdorff measure (Neumann condition). It is found that the scaling properties of the spread harmonic measures on prefractal boundaries are characterized by a set of multifractal exponent functions depending on the only scaling parameter. A conjectural extension of the spread harmonic measures to fractal boundaries is proposed. The developed concepts are applied to give a new explanation of the anomalous constant phase angle frequency behavior in electrochemistry.
Molecular Mechanisms of Renal Ammonia Transport
Authors: Weiner I. David , Hamm L. Lee
Published: September 2006

Acid-base homeostasis to a great extent relies on renal ammonia metabolism. In the past several years, seminal studies have generated important new insights into the mechanisms of renal ammonia transport. In particular, the theory that ammonia transport occurs almost exclusively through nonionic NH3 diffusion and NH4+ trapping has given way to a model postulating that a variety of proteins specifically transport NH3 and NH4+ and that this transport is critical for normal ammonia metabolism. Many of these proteins transport primarily H+ or K+ but also transport NH4+. Nonerythroid Rh glycoproteins transport ammonia and may represent critical facilitators of ammonia transport in the kidney. This review discusses the underlying aspects of renal ammonia transport as well as specific proteins with important roles in renal ammonia transport.
Epithelial lining fluid free IGF-I-to-PAPP-A ratio is associated with bronchopulmonary dysplasia in preterm infants
Authors: Capoluongo Ettore , Ameglio Franco , Lulli Paola , Minucci Angelo , Santonocito Concetta , Concolino Paola , Di Stasio Enrico , Boccacci Simona , Vendettuoli Valentina , Giuratrabocchetta Giuseppe , De Cunto Angela , Tana Milena , Romagnoli Costantino , Zuppi Cecilia , Vento Giovanni
Published: September 2006

Preterm newborns developing retinopathy of prematurity (ROP) and bronchopulmonary dysplasia (BPD) show persistently low levels of insulin-like growth factor-I (IGF-I) in sera. They also present higher free IGF-I concentrations in epithelial lining fluids (ELFs) and lung tissues. Pregnancy-associated plasma protein-A (PAPP-A) is a metalloproteinase that dissociates three binding proteins from the active form of IGF-I, namely free IGF-I. The present study analyzes the ELF concentrations of free IGF-I, PAPP-A, and their ratios in preterm newborns developing or not BPD, defined as O2 dependence at 36 wk postmenstrual age. Bronchoalveolar lavage fluids of 41 infants (34 without and 7 with BPD) were analyzed on the 2nd and 4th day after birth. Infants developing BPD showed increased ELF free IGF-I and decreased PAPP-A concentrations on both days 2 and 4 compared with newborns without BPD. A nonsignificant trend between these 2 days was observed for free IGF-I (increasing) and PAPP-A (decreasing). On the same days, the free IGF-I-to-PAPP-A ratio was always significantly higher in patients developing BPD. These differences were more significant than those of IGF-I or PAPP-A when individually evaluated. A multivariate analysis confirmed the significance for free IGF-I on day 4, whereas the ratio was confirmed on both days 2 and 4. The same ratio was significantly correlated with some indexes of disease severity, such as hours of oxygen administration, days of hospitalization, and ROP severity scores. Finally, the ratio between ELF free IGF-I and PAPP-A appears to be a useful marker for lung injury of premature newborns.
Population approaches to estimate minimal model indexes of insulin sensitivity and glucose effectiveness using full and reduced sampling schedules
Authors: Krudys Kevin M. , Kahn Steven E. , Vicini Paolo
Published: September 2006

The intravenous glucose tolerance test (IVGTT) interpreted with the minimal model provides individual indexes of insulin sensitivity (SI) and glucose effectiveness (SG). In population studies, the traditional approach, the standard two-stage (STS) method, fails to account for uncertainty in individual estimates, resulting in an overestimation of between-subject variability. Furthermore, in the presence of reduced sampling and/or insulin resistance, individual estimates may be unobtainable, biasing population information. Therefore, we investigated the use of two population approaches, the iterative two-stage (ITS) method and nonlinear mixed-effects modeling (NM), in a population ( n = 235) of insulin-sensitive and insulin-resistant subjects under full (FSS, 33 samples) and reduced [RSS(240-min), 13 samples and RSS(180-min), 12 samples] IVGTT sampling schedules. All three population methods gave similar results with the FSS. Using RSS(240), the three methods gave similar results for SI, but SG population means were overestimated. With RSS(180), SI and SG population means were higher for all three methods compared with their FSS counterparts. NM estimated similar between-subject variability (19% SG, 53% SI) with RSS(180), whereas ITS showed regression to the mean for SG (0.01% SG, 56% SI) and STS provided larger population variability in SI (29% SG, 91% SI). NM provided individual estimates for all subjects, whereas the two-stage methods failed in 16–18% of the subjects using RSS(180) and 6–14% using RSS(240). We conclude that population approaches, specifically NM, are useful in studies with a sparsely sampled IVGTT (∼12 samples) of short duration (∼3 h) and when individual parameter estimates in all subjects are desired.
Model of albumin reabsorption in the proximal tubule
Authors: Lazzara Matthew J. , Deen William M.
Published: September 2006

Normally, the small amount of albumin which passes through the glomerular capillary wall is almost completely reabsorbed in the proximal tubule, via an endocytic mechanism, but the reabsorptive process can be overwhelmed if the filtered load of albumin is too large. To examine the factors that control the fractional reabsorption of albumin ( f), we developed a mathematical model which assumes saturable endocytosis kinetics with a maximum reabsorptive capacity, V max, and which includes the effects of flow and diffusion in the lumen. Limitations in albumin transport from the bulk tubule fluid to the endocytic sites at the bases of the microvilli had only a modest (8%) effect on the value of V max needed to fit micropuncture data on tubule albumin concentrations in rats. For moderate changes in filtered load, there was much greater sensitivity of f to SNGFR than to the albumin concentration of the filtrate ( C0). A 50% increase in SNGFR was predicted to cause four- to fivefold increases in albumin excretion in rats or humans. For large increases in C0, as might result from defects in glomerular sieving, there was a threshold at which the reabsorptive process became saturated and f fell sharply. That threshold corresponded to sieving coefficients of 10−3 to 10−2, the higher values occurring at reduced SNGFR. The predictions of the present model contrast with those of one proposed recently by Smithies ( 32 ), which does not include the effects of tubule flow rate.
Renal prostaglandin E2 receptor (EP) expression profile is altered in streptozotocin and B6-Ins2Akita type I diabetic mice
Authors: Nasrallah Rania , Xiong Huaqi , Hébert Richard L.
Published: September 2006

The homeostatic function of prostaglandin E2 (PGE2) is dependent on a balance of EP receptor-mediated events. A disruption in this balance may contribute to the progression of renal injury. Although PGE2 excretion is elevated in diabetes, the expression of specific EP receptor subtypes has not been studied in the diabetic kidney. Therefore, the purpose of this study was to characterize the expression profile of four EP receptor subtypes (EP1-4) in 16-wk streptozotocin (STZ) and B6-Ins2Akita type I diabetic mice. In diabetic mice, the ratio of kidney weight to body weight was increased twofold compared with controls, blood glucose was elevated, but urine albumin was only increased in B6-Ins2Akita mice. The excretion of PGE2 and its metabolite was augmented two- to fourfold as determined by enzyme immunoassay. Accordingly, renal cyclooxygenases were also increased in diabetic mice, with isoform-specific and regional differences in each model. Finally, there was altered EP1-4 receptor expression in diabetic kidneys, with significant differences between STZ and B6-Ins2Akita mice (fold-control). In STZ mice, cortical EP1 increased by 1.6, EP3 increased by 2.3, and EP4 decreased by 0.63; yet in B6-Ins2Akita mice, cortical EP1 increased by 2.4, but there was a general decrease in the remaining subtypes. Similarly, in the STZ medulla EP3 increased by 3.6, but both EP1 and EP3 increased by 5.5 and 1.95, respectively, in B6-Ins2Akita mice. Therefore, knowing the pattern of change in relative EP receptor expression in the kidney could be useful in identifying specific EP targets for the prevention of various components of diabetic kidney disease.
Powder diffraction data for N,N'-diphenylguanidinium nitrate at room and low temperatures
Authors: Silva Pedro Pereira , Silva Manuela Ramos , Paixão José António , Beja Ana Matos
Published: September 2006

X-ray powder diffraction data for N,N'-diphenylguanidinium nitrate, within the temperature range of 103–293 K, are reported. The pattern at 293 K was confirmed by a fitting of the overall parameters performed with FULLPROF using the atomic parameters obtained from single-crystal studies. The compound is orthorhombic, space group Pna21 (33), with unit-cell parameters a=1.7058(4) nm, b=1.3933(3) nm, c=0.5821(1) nm, and V=1.3834(6) nm3. The unit-cell parameters for the other six temperatures measured were determined by performing pattern matching with FULLPROF. The unit-cell volume contracted on cooling from 1.3834(6) nm3 to 1.3403(4) nm3. The thermal expansion tensor was calculated from the changes of the unit-cell parameters with temperature. The elements of the thermal expansion tensor at 293 K are α11=125(4),α22=57(9), and α33=82(3)×10−6 K−1.
Synthesis and X-ray characterization of Li0.5M0.25TiOAsO4 (M=Mg,Co,Ni,Zn) oxyarsenates
Authors: Chakir M. , El Jazouli A. , Chaminade J. P.
Published: September 2006

Li0.5M0.25TiOAsO4 (M=Mg,Co,Ni,Zn) oxyarsenates powders were prepared by coprecipitation method from dilute solution of Li2CO3,M(NO3)2×H2O (M=Mg,Co,Ni,Zn), (NH4)H2AsO4 and TiCl4 in ethanol. The resulting powders, obtained after drying at about 60 °C, were heated progressively with intermittent grindings at 200 °C–750 °C in air. These new compounds crystallize in the monoclinic system with space group P21∕c. Their parameters are functions of M2+ ion size.
Synthesis and crystal structure of Na3.5Cr1.5Co0.5(PO4)3 phosphate
Authors: Chakir Mohamed , El Jazouli Abdelaziz , Chaminade Jean-Pierre
Published: September 2006

A new Nasicon phosphates series [Na3+xCr2−xCox(PO4)3(0⩽x⩽1)] was synthesized by a coprecipitation method and structurally characterized by powder X-ray diffraction. The selected compound Na3.5Cr1.5Co0.5(PO4)3 (x=0.5) crystallizes in the R3c space group with the following hexagonal unit-cell dimensions: ah=8.7285(3) Å, ch=21.580(2) Å, V=1423.8(1) Å3, and Z=6. This three-dimensional framework is built of PO4 tetrahedra and Cr∕CoO6 octahedra sharing corners. Na atoms occupy totally M(1) sites and partially M(2) sites.
X-ray powder diffraction analysis of tegafur
Authors: Needham F. , Faber J. , Fawcett T. G. , Olson D. H.
Published: September 2006

An experimental X-ray powder diffraction pattern was produced and analyzed for alpha-polymorphic tegafur, also called Ftorafur (an antineoplastic agent). The indexed data matched the powder patterns in the ICDD PDF-4/Organics database calculated from the reported single-crystal X-ray diffraction data in the Cambridge Structural Database. Alpha tegafur has a triclinic crystal system, with reduced cell parameters of a=16.720(6) Å, b=9.021(5) Å, c=5.995(3) Å, α=93.66(4)°, β=93.15(8)°, γ=100.14(4)°. There are four formula units contained in one unit cell. The cell volume and space group were determined to be 886.27 Å3 and P-1, respectively.
X-ray and neutron powder diffraction studies of (Ba1−xSrx)Y2CuO5
Authors: Yang Z. , Wong-Ng W. , Cook L. P. , Kaduk J. A. , Huang Q. Z.
Published: September 2006

This paper reports the results of crystallography and crystal chemistry investigation of the (Ba1−xSrx)Y2CuO5 (“green phase”) solid solution series by X-ray powder diffraction (XPD) and neutron powder diffraction techniques. The single phase regions for (Ba1−xSrx)Y2CuO5 were determined to be 0⩽x⩽0.3 for samples prepared at 810 °C in 100 Pa pO2, and 0⩽x⩽0.7 for samples prepared at 930 °C in air. All single phase (Ba1−xSrx)Y2CuO5 samples are isostructural to BaY2CuO5 and can be indexed using an orthorhombic cell with the space group Pnma. Lattice parameters, a,b,c and the cell volume, V, of the (Ba1−xSrx)Y2CuO5 members decrease linearly with increasing Sr substitution (x) on the Ba site. The general structure of (Ba1−xSrx)Y2CuO5 can be considered as having a three-dimensional interconnected network of [YO7],[(Ba,Sr)O11], and [CuO5] polyhedra. The copper ions are located inside distorted [CuO5] “square” pyramids. These pyramids are connected by the [Y2O11] groups that are formed from two monocapped [YO7] trigonal prisms sharing a triangular face. The Ba2+ ions are found to reside in distorted 11-fold coordinated cages. The oxygen sites are essentially fully occupied. XPD reference patterns of two members of the series, (Ba0.3Sr0.7)Y2CuO5 and (Ba0.7Sr0.3)Y2CuO5, were prepared for inclusion in the powder diffraction file.
X-ray powder diffraction analysis of K3Nb3WO9(AsO4)2
Authors: Belkhiri S. , Mezaoui D. , Rebbah H. , Ouhenia S. , Belkhir M. A.
Published: September 2006

K3Nb3WO9(AsO4)2 has been investigated by means of X-ray powder diffraction. Powder diffraction data were obtained by conventional diffractometer with Kα radiation. Unit-cell dimensions were determined by an indexing program based on variation of parameters by successive dichotomies. An orthorhombic cell (space group Pnma) was found with a=15.001 (1) Å, b=14.814(1) Å, c=7.2374 (8) Å, and V=1608.4 (4) A3. The figures of merit were calculated to be M(20)=35.9 and F(20)=70.8 (0.0055,51).
Crystal structure of calcium cobalt orthophosphate, CaCo[Ca0.1Co0.9](PO4)2
Authors: Fukuda Koichiro , Hasegawa Hajime , Iwata Tomoyuki , Hashimoto Shinobu
Published: September 2006

Crystal structure of Ca1.1Co1.9(PO4)2was successfully determined from laboratory X-ray powder diffraction data (CoKα) using direct methods and the Rietveld refinement. The crystal structure was found to be monoclinic (space groupP21∕n,Z=4) with lattice dimensions ofa=1.452 67(5) nm,b=0.494 34(1) nm,c=0.867 50(3) nm,β=92.316(1)°, andV=0.622 45(3) nm3. The final reliability indices calculated from the Rietveld refinement wereRwp=3.93%,Rp=3.02%,RB=4.10%, andS=1.48. Both Co and Ca atoms were distributed over the 2aand 2dsites with a preference of Ca at the 2dsite. The coexistence of Co and Ca on the 2aand 2dsites is indispensable for stabilizing Ca1.1Co1.9(PO4)2in the Ca3(PO4)2-Co3(PO4)2system.
New X-ray powder diffraction data for Mo2.85Al1.91Si4.81
Authors: Tayebifard S. A. , Ahmadi K. , Yazdani-Rad R. , Doroudian M.
Published: September 2006

X-ray powder diffraction data for Mo2.85Al1.91Si4.81 are reported. The new Mo2.85Al1.91Si4.81 compound was successfully prepared using the self-propagating high-temperature synthesis (SHS) technique. The starting atomic mixture of reactant powders was Mo+2(1−x)Si+2xAl with x=0.3. The final powder compound obtained by the SHS technique was determined to be Mo2.85Al1.91Si4.81 by ICP-AES. X-ray powder diffraction pattern of Mo2.85Al1.91Si4.81 was recorded using an X-ray powder diffractometer, Cu Kα radiation, and analyzed by automatic indexing programs. Mo2.85Al1.91Si4.81 was found to be hexagonal with a=4.6929(2) Å and c=6.5515(4) Å. The XRD results are in good agreement with those of Mo2.85Ga2Si4.15.
Structural characterization of two K2SnX(PO4)3 (X=Fe,Yb) with langbeinite structure
Authors: Aatiq Abderrahim , Haggouch Btissame , Bakri Rachid , Lakhdar Youssef , Saadoune Ismael
Published: September 2006

Structures of two K2SnX(PO4)3(X=Fe,Yb) phosphates, obtained by conventional solid state reaction techniques at 950 °C, were determined at room temperature by X-ray powder diffraction using Rietveld analysis. The two materials exhibit the langbeinite-type structure (P213 space group, Z=4). Cubic unit cell parameter values are: a=9.9217(4) Å and a=10.1583(4) Å for K2SnFe(PO4)3 and K2SnYb(PO4)3, respectively. Structural refinements show that the two crystallographically independent octahedral sites (of symmetry 3) have a mixed Sn∕X (X=Fe,Yb) population although ordering is stronger in the Yb phase than in the Fe phase.
X-ray powder diffraction study of cesium ammonium hexachlorotellurate [Cs0.86(NH4)0.14]2TeCl6
Authors: Karray R. , Kabadou A. , Ben Salah A. , van der Lee A.
Published: September 2006

The crystal structure of cesium ammonium hexachlorotellurate [Cs0.86(NH4)0.14]2TeCl6, has been determined using X-ray powder diffraction techniques. At room temperature, the title compound crystallizes in the cubic space groupFm3m, with a lattice parametera=10.470(17) Å. The Rietveld refinement of the structure led to final confidence factorsRp=0.0338 andRwp=0.0487. The structure of [Cs0.86(NH4)0.14]2TeCl6belongs to the large family of K2PtCl6-related structures. The H atoms of the ammonium group are orientated with its apex toward Te atoms as seen in the related compound (NH4)2SiF6. An IR spectroscopic study was performed to confirm the results of the diffraction method, notably concerning the presence of the ammonium group.
Ophthalmologic Manifestations of Cutaneous Conditions
Authors: Freiman Anatoli , Ting Patricia T. , Barankin Benjamin , Stanciu Monica , Rudnisky Chris
Published: September 2006

Many cutaneous conditions have associated ophthalmologic findings, which are important to recognize for both dermatologists and ophthalmologists. This review highlights some important ophthalmologic manifestations associated with neurocutaneous syndromes and inherited connective tissue diseases.
Further Support for the Common Variants in Complement Factor H (Y402H) and LOC387715 (A69S) Genes as Major Risk Factors for the Exudative Age-Related Macular Degeneration
Authors: Shastry Barkur S.
Published: September 2006

In developed countries, age-related macular degeneration (ARMD) is a common cause of blindness in the elderly. It is a clinically complex and genetically heterogeneous disorder. The etiology of the disorder may involve interactions between genetic and environmental factors. Recently it has been reported that a polymorphism in the complement factor H (CFH) and LOC387715 gene may determine the susceptibility of individuals to ARMD. In order to replicate and to determine the frequency of this polymorphism in ARMD patients, we have analyzed two unrelated families having exudative ARMD. Our analysis has identified the same common polymorphism (Y402H) in the CFH gene in one family and the A69S polymorphism in the LOC387715 gene in the second family. These results further support the notion that CFH and LOC387715 genes are the major risk factors for ARMD.
Is There Still a Clinical Use for Scanning Laser Polarimetry with Fixed Corneal Compensator?
Authors: Vetrugno Michele , Sista Dario , Trabucco Tiziana , Sborgia Giancarlo , Ferreri Paolo
Published: September 2006

Purpose: To compare the scanning laser polarimetry device with a fixed corneal compensator (GDx FCC) with the new version with a variable corneal compensator (GDx VCC) in healthy subjects. Methods: A prospective, nonrandomized, comparative trial was carried out with both the FCC and the VCC systems on 130 healthy volunteers. The FCC measurements were divided into 2 subgroups, in accordance with the appearance of the macula. Subjects with a uniform aspect of the macula were included in the macula-‘negative’ group (macula–), whereas subjects with an irregular macular appearance with FCC were included in the macula-‘positive’ group (macula+). Data relative to all the GDx parameters were examined. For each parameter, we compared the data obtained by the FCC to the VCC models. Subsequently we compared each FCC subgroup (macula+ and macula–) to VCC. Results: A total of 67 subjects entered the macula– group and 63 the macula+ group. FCC significantly overestimated the average parameters and underestimated the number, the modulation and also the ratio parameters. The only parameter showing no difference was symmetry. Similar trends were also evident when the subjects were divided into the macula+ and – subgroups. Conclusion: Individual variations of corneal birefringence, which are not completely corrected by FCC, result in over- or underestimation of retinal nerve fiber layer parameters. This measurement error cannot be eliminated, not even by only selecting patients with a uniform aspect of macular scan. For this reason GDx FCC does not seem to be an acceptable tool in the early diagnosis of glaucoma, and modern versions of this device should be preferred.