bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of piezoelectric poly(vinylidene fluoride) polymers for use in space environments. I. Temperature limitations
Authors: Dargaville Tim R. , Celina Mathew , Chaplya Pavel M. 
Published: April 2005

AbstractSmart materials, such as thin‐film piezoelectric polymers, are interesting for potential applications on Gossamer spacecraft. This investigation aims to predict the performance and long‐term stability of the piezoelectric properties of poly(vinylidene fluoride) (PVDF) and its copolymers under conditions simulating the low‐Earth‐orbit environment. To examine the effects of temperature on the piezoelectric properties of PVDF, poly(vinylidenefluoride‐co‐trifluoroethylene), and poly(vinylidenefluoride‐co‐hexafluoropropylene), the d33 piezoelectric coefficients were measured up to 160 °C, and the electric displacement/electric field (D–E) hysteresis loops were measured from −80 to +110 °C. The room‐temperature d33 coefficient of PVDF homopolymer films, annealed at 50, 80, and 125 °C, dropped rapidly within a few days of thermal exposure and then remained unchanged. In contrast, the TrFE copolymer exhibited greater thermal stability than the homopolymer, with d33 remaining almost unchanged up to 125 °C. The HFP copolymer exhibited poor retention of d33 at temperatures above 80 °C. In situ D–E loop measurements from −80 to +110 °C showed that the remanent polarization of the TrFE copolymer was more stable than that of the PVDF homopolymer. D–E hysteresis loop and d33 results were also compared with the deflection of the PVDF homopolymer and TrFE copolymer bimorphs tested over a wide temperature range. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1310‐1320, 2005
Effects of salmon carcasses on experimental stream ecosystems in Hokkaido, Japan
Authors: Yanai Seiji , Kochi Kaori 
Published: April 2005

AbstractThe effects of salmon carcasses on dissolved nutrients, epilithic production, leaf decomposition rates, and aquatic invertebrates were examined using 10‐m‐long artificial channels fed by an adjacent natural stream in Hokkaido, northern Japan. Bags containing maple leaf litter were placed in nine channels, each of which was assigned to one of three treatments with three replicates, for 6 weeks in fall 2002. The three treatments were: (1) salmon carcasses+invertebrates, (2) invertebrates only, and (3) control (no salmon carcasses or invertebrates added). Nutrient concentrations, biomass of epilithic algae (chlorophyll), leaf weight loss, abundance and biomass of invertebrates in the leaf packs were compared among the three treatments at 14, 27, and 40 days after the beginning of the experiment. The NH4+ in stream water and chlorophyll concentrations of epilithic algae were higher in the salmon treatment than the other treatments, and the maple leaves decomposed faster in the salmon treatment than in the other treatments. Moreover, the N content of the leaves was highest and the C/N ratio was lowest in the salmon treatment, although not significantly so. The abundance and biomass of the dominant leaf‐shredding invertebrate Goerodes satoi did not differ between the first two treatments. However, the stable N isotope ratio in G. satoi was nearly 3‰ higher in the salmon treatment, suggesting that around 20% of salmon‐derived N was taken up by this shredder. Our results indicate that salmon carcasses affect stream ecosystems directly by enhancing primary production, indirectly by accelerating woody leaf decomposition, and finally by incorporating into the food web primary consumers that utilize fertilized woody leaves.
Steady-state convection-diffusion problems
Authors: Stynes Martin 
Published: April 2005

In convection-diffusion problems, transport processes dominate while diffusion effects are confined to a relatively small part of the domain. This state of affairs means that one cannot rely on the formal ellipticity of the differential operator to ensure the convergence of standard numerical algorithms. Thus new ideas and approaches are required.The survey begins by examining the asymptotic nature of solutions to stationary convection-diffusion problems. This provides a suitable framework for the understanding of these solutions and the difficulties that numerical techniques will face. Various numerical methods expressly designed for convection-diffusion problems are then presented and extensively discussed. These include finite difference and finite element methods and the use of special meshes.
A comparison of conventional and alternative agroecosystems using alfalfa (Medicago sativa) and winter wheat (Triticum aestivum)
Authors: Skelton Laura E. , Barrett Gary W. 
Published: April 2005

AbstractNatural systems agriculture is based on an understanding that natural systems are self-sustaining due to regulatory mechanisms and processes that help to ensure the long-term maintenance of the ecosystem. An agroecosystem modeled after nature should encompass greater stability and biodiversity at all levels of organization than an agroecosystem based on conventional agricultural practices. The main objective of this study was to determine whether agroecosystems modeled after nature exhibit advantages over conventional agroecosystems. Five treatments were examined: winter wheat (Triticum aestivumL.) monoculture, alfalfa (Medicago sativaL.) monoculture, strip-cropped alfalfa and wheat, and two alfalfa–wheat intercrops (one no-till and one conservation-till). Indicators of ecosystem function studied included primary productivity, soil fertility, plant nitrogen (N) concentration, and abundances of arthropod pests and predators. No fertilizers or pesticides were used prior to or during this investigation. Monoculture, strip-crop and conservation-till treatments produced significantly higher yields than no-till intercropped alfalfa and wheat. Although yields from the no-till intercrop were low, wheat protein values were comparable to other treatments. Soil N concentrations tended to be high in treatments containing alfalfa. Insect pests preferred alfalfa and were, therefore, often more abundant in treatments containing high percentages of alfalfa, as were predators such as spiders. Researching alternatives to monoculture agroecosystems, such as the intercrop systems in this study, may provide us insight into a true natural systems agriculture.
Meeting the challenge of disease management in perennial grain cropping systems
Authors: Cox C.M. , Garrett K.A. , Bockus W.W. 
Published: April 2005

AbstractPerennial grain production will likely present unique challenges for managing diseases that affect the productivity and longevity of crops being considered. Typical cultural practices effective at reducing soil- and residue-borne pathogens, such as annual crop rotations, delayed fall planting, and tillage, are not feasible in perennial systems. Consequently, soil- and residue-borne pathogens, and pathogens such as root colonizers and viruses that survive in live tissue, may increase in importance in a perennial grain crop. Resistance genes will undeniably be important defenses against disease. However, it is seldom, if ever, possible to incorporate within a single cultivar resistance to all existing and future important diseases. Furthermore, genes vulnerable to ‘boom and bust’ cycles are generally short-lived when deployed in monocultures. For these reasons, the use of mixtures of crop cultivars or species that vary in resistance functions will likely be an important strategy for managing diseases and pests of perennial grains. Burning of plant residue, a natural phenomenon in native perennial grass systems, may also be an effective disease management strategy. The successful implementation of these management tools may reduce or eliminate the risk that perennial grain crops will become pathogen refugia that affect neighboring annual plantings and the productivity of perennial plants.
Perennial grain crops: A synthesis of ecology and plant breeding
Authors: DeHaan L.R. , Van Tassel D.L. , Cox T.S. 
Published: April 2005

AbstractPerennial grain crops would address many agricultural problems, including soil erosion, nutrient loss and pesticide contamination. Doubts about the possibility of perennial grain crops rest upon two assumptions: (1) that the relationship between yield and longevity is a fixed function that cannot be influenced by selection, mutation or environmental changes; and (2) that yield and longevity trade off in a bivariate manner to the exclusion of all other traits. These assumptions are consistent with the phenotypic trade-off model, but recent research suggests that a quantitative genetic model is a more appropriate approach to trade-offs. In the quantitative genetic model, environmental and genetic changes can result in increases in two traits simultaneously even when a trade-off, or negative correlation, exists between the two traits. Empirical evidence that the trade-off between perenniality and reproductive allocation is not fixed comes from wild, herbaceous perennials that can produce more than 2000 kg seed ha−1 in the temperate zone, and herbaceous perennial crops that produce on average 8900 kg fruit ha−1 in the tropics. Ecological literature suggests that most perennials produce small amounts of seed relative to their vegetative growth not as a physiological absolute, but rather as a result of natural selection in a stable, competitive environment favoring longevity. By selecting strongly for seed yield in a population of perennial plants, the plant breeder can likely achieve that which is rare in nature—a high seed-yielding perennial plant. The same general methodologies that have allowed annual grain breeders to increase grain yield and push many combinations of negatively correlated traits to levels of expression not seen in nature are available to the perennial grain breeder. Perennial grain breeders are integrating ecological principles and traditional plant breeding methods in their efforts to develop perennial grain wheat (Triticum spp.), sorghum (Sorghum spp.), sunflower (Helianthus spp.), Illinois bundleflower (Desmanthus illinoensis) and rice (Oryza spp.).
Structural similarity to bridge sequence space: Finding new families on the bridges
Authors: Shah Parantu K. , Aloy Patrick , Bork Peer , Russell Robert B. 
Published: April 2005

AbstractStructures for protein domains have increased rapidly in recent years owing to advances in structural biology and structural genomics projects. New structures are often similar to those solved previously, and such similarities can give insights into function by linking poorly understood families to those that are better characterized. They also allow the possibility of combing information to find still more proteins adopting a similar structure and sometimes a similar function, and to reprioritize families in structural genomics pipelines. We explore this possibility here by preparing merged profiles for pairs of structurally similar, but not necessarily sequence‐similar, domains within the SMART and Pfam database by way of the Structural Classification of Proteins (SCOP). We show that such profiles are often able to successfully identify further members of the same superfamily and thus can be used to increase the sensitivity of database searching methods like HMMer and PSI‐BLAST. We perform detailed benchmarks using the SMART and Pfam databases with four complete genomes frequently used as annotation benchmarks. We quantify the associated increase in structural information in Swissprot and discuss examples illustrating the applicability of this approach to understand functional and evolutionary relationships between protein families.
Sensitivity of the folding/unfolding transition state ensemble of chymotrypsin inhibitor 2 to changes in temperature and solvent
Authors: Day Ryan , Daggett Valerie 
Published: April 2005

AbstractTo better characterize the transition state for folding/unfolding and its sensitivity to environmental changes, we have run multiple molecular dynamics simulations of chymotrypsin inhibitor 2 (CI2) under varying solvent conditions and temperature. The transition state structures agree well with experiment, and are similar under all of the conditions investigated here. Increasing the temperature leads to some movement in the position of the transition state along several reaction coordinates, as measured by changes in properties of the transition state structures. These structural changes are in the direction of a more native‐like transition state as denaturation conditions become more severe, as expected for a Hammond effect. These structural changes are not, however, reflected in the global structure as measured by the total number of contacts or the average S‐values. These results suggest that the small changes in average Φ‐values with temperature seen by experiment may be due to an increase in the sensitivity of the transition state to mutation rather than a change in the average structure of the transition state. A simple analysis of the rates of unfolding indicates that the free energy barrier to unfolding decreases with increasing temperature, but even in our very high temperature simulations there is a small free energy barrier.
Ocular side‐effects of tolterodine and oxybutynin, a single‐blind prospective randomized trial
Authors: Altan‐Yaycioglu R. , Yaycioglu O. , Aydin Akova Y. , Guvel S. , Ozkardes H. 
Published: April 2005

AimTo evaluate the effects of tolterodine and oxybutynin on visual accommodation, pupillary diameter, intraocular pressure and tear secretion in women with overactive bladder.MethodsOne hundred and four eyes from 52 consecutive female patients (age range: 22–60 years) with a urodynamic diagnosis of overactive bladder were prospectively investigated. Patients with a history of ocular disease or surgery were excluded. The subjects were randomly assigned to one of two groups: Group I received 2 mg tolterodine bid and Group II received 5 mg oxybutynin tid. All patients were evaluated at baseline (day 0) and after 1 month of treatment (day 28) by an ophthalmologist who was blinded to the medication. At each time point, a complete ophthalmic examination was performed and accommodation amplitude (AA), and pupillary diameter (PD) in dim and bright light were recorded. As well, tear secretion was assessed based on tear film break‐up time and Schirmer I‐test results. Statistical comparisons were made using the chi‐square test, Student's t‐test and Mann–Whitney U‐test, as appropriate.ResultsTwenty‐eight patients (56 eyes) received tolterodine and 24 patients (48 eyes) received oxybutynin. The mean ages of the two groups were similar (P = 0.523). After 4 weeks of treatment, AA was significantly lower in the oxybutynin treated group (P = 0.003, 95% CI 0.15, 0.62) whereas there was no significant change in AA in the tolterodine treated group (P = 0.155, 95% CI −0.042, 0.86). At day 28, PD in dim light was significantly larger in the tolterodine treated group (P = 0.031, 95% CI −0.82, −0.06), whereas no significant change in PD in dim light was noted in the oxybutynin treated group (P = 0.330, 95% CI −0.38, 0.18)). Neither group showed a significant change in PD in bright light values on day 28 (P > 0.05 for both). In each group, the differences from day 0 to day 28 for intraocular pressure, and Schirmer‐I results were insignificant (P > 0.05 for all). Both groups had significantly shorter tear film break‐up time after 1 month of therapy (P = 0.014 (95% CI 0.47, 3.81) and P = 0.02 (95% CI 1.14, 4.61) for the tolterodine and oxybutynin treated groups, respectively).ConclusionFour weeks of standard‐dose oxybutynin treatment in women with overactive bladder decreases AA significantly, whereas the same duration of standard‐dose tolterodine does not have this effect. However, tolterodine seemed to affect PD in dim light. One month of treatment with either of these anticholinergic drugs shortens tear film break‐up time significantly. Concerning ocular side‐effects, tolterodine seems to offer an advantage over oxybutynin because it does not affect AA, however, the shorter tear film break‐up time with both agents suggests potential problems for patients who already have dry eye.
Determination of the bioavailability of gentamicin to the lungs following inhalation from two jet nebulizers
Authors: Al‐Amoud A. I. , Clark B. J. , Assi K. A. , Chrystyn H. 
Published: April 2005

AimsTo determine the bioavailability of gentamicin to the lung following inhalation from two jet nebulizers.MethodsSerial urine samples were obtained from 10 volunteers after a 80 mg dose given orally, nebulized from a Pari LC + (PARI) and MicroNeb III (MN) devices, or after a 40 mg intravenous dose. In vitro aerodynamic characteristics of the nebulized doses were also determined.ResultsThe mean (SD) absolute gentamicin lung bioavailalibility following delivery by PARI and MN devices was 1.4 (0.4) and 1.7 (0.5) %. The mass median aerodynamic diameter (MMAD) of the drug particles from the PARI and MN systems was 8.6 (0.6) and 6.7 (0.5) µm and the corresponding fine particle doses (FPD) were 10.2 (2.8) and 11.7 (1.5) mg.ConclusionsThe MMAD and FPD data reflect the poor lung deposition of gentamicin identified by urinary excretion.
Chlorpropamide 2‐hydroxylation is catalysed by CYP2C9 and CYP2C19 in vitro: chlorpropamide disposition is influenced by CYP2C9, but not by CYP2C19 genetic polymorphism
Authors: Shon Ji‐Hong , Yoon Young‐Ran , Kim Min‐Jung , Kim Kyoung‐Ah , Lim Young‐Chae , Liu Kwang‐Hyeon , Shin Dong‐Hoon , Lee Chung Han , Cha In‐June , Shin Jae‐Gook 
Published: April 2005

AimsWe evaluated the involvement of cytochrome P450 (CYP) isoforms 2C9 and 2C19 in chlorpropamide 2‐hydroxylation in vitro and in chlorpropamide disposition in vivo.MethodsTo identify CYP isoforms(s) that catalyse 2‐hydroxylation of chlorpropamide, the incubation studies were conducted using human liver microsomes and recombinant CYP isoforms. To evaluate whether genetic polymorphisms of CYP2C9 and/or CYP2C19 influence the disposition of chlorpropamide, a single oral dose of 250 mg chlorpropamide was administered to 21 healthy subjects pregenotyped for CYP2C9 and CYP2C19.ResultsIn human liver microsomal incubation studies, the formation of 2‐hydroxychlorpropamide (2‐OH‐chlorpropamide), a major chlorpropamide metabolite in human, has been best described by a one‐enzyme model with estimated Km and Vmax of 121.7 ± 19.9 µm and 16.1 ± 5.0 pmol min−1 mg−1 protein, respectively. In incubation studies using human recombinant CYP isoforms, however, 2‐OH‐chlorpropamide was formed by both CYP2C9 and CYP2C19 with similar intrinsic clearances (CYP2C9 vs. CYP2C19: 0.26 vs. 0.22 µl min−1 nmol−1 protein). Formation of 2‐OH‐chlorpropamide in human liver microsomes was significantly inhibited by sulfaphenazole, but not by S‐mephenytoin, ketoconazole, quinidine, or furafylline. In in vivo clinical trials, eight subjects with the CYP2C9*1/*3 genotype exhibited significantly lower nonrenal clearance [*1/*3 vs.*1/*1: 1.8 ± 0.2 vs. 2.4 ± 0.1 ml h−1 kg−1, P < 0.05; 95% confidence interval (CI) on the difference 0.2, 1.0] and higher metabolic ratios (of chlorpropamide/2‐OH‐chlorpropamide in urine: *1/*3 vs.*1/*1: 1.01 ± 0.19 vs. 0.56 ± 0.08, P < 0.05; 95% CI on the difference − 0.9, − 0.1) than did 13 subjects with CYP2C9*1/*1 genotype. In contrast, no differences in chlorpropamide pharmacokinetics were observed for subjects with the CYP2C19 extensive metabolizer vs. poor metabolizer genotypes.ConclusionsThese results suggest that chlorpropamide disposition is principally determined by CYP2C9 activity in vivo, although both CYP2C9 and CYP2C19 have a catalysing activity of chlorpropamide 2‐hydroxylation pathway.
Characterization of macrophage subpopulations in colon cancer using tissue microarrays
Authors: Sickert D , Aust D E , Langer S , Haupt I , Baretton G B , Dieter P 
Published: April 2005

Aims : To determine the pattern of macrophage infiltration in colon cancers and its correlation with clinicopathological characteristics.Methods and results : Colon cancers from 100 patients were arrayed into a tissue microarray (TMA). Four cores per tumour were taken: three from the invasion front (IF) and one from the tumour surface (TS). Macrophages were quantified by immunohistochemistry with antibodies to the PG‐M1, KP‐1, MRP8, MRP14 and MRP8/14 antigens. The number of macrophages was significantly higher in the TS cores than in the IF cores and both tumour sites showed a higher number of macrophages than the normal mucosa. The number of macrophages decreased in higher stage tumours. The different tumour‐associated macrophage (TAM) subpopulations were positively correlated with each other.Conclusions : The increased number of macrophages in cancers compared with normal colon mucosa indicates that macrophages are attracted to the tumour site. However, decreasing macrophages in higher stage colon cancers suggest that this attraction decreases with tumour progression.
Use of carbon‐11 in Populus shows that exogenous jasmonic acid increases biosynthesis of isoprene from recently fixed carbon
Authors: FERRIERI RICHARD A. , GRAY DENNIS W. , BABST BENJAMIN A. , SCHUELLER MICHAEL J. , SCHLYER DAVID J. , THORPE MICHAEL R. , ORIANS COLIN M. , LERDAU MANUEL 
Published: April 2005

ABSTRACTA new approach for pulse labelling of plants using the short‐lived positron emitting radioisotope carbon‐11 (half‐life: 20.4 min) as 11CO2 is reported together with its application to measuring [11C]isoprene emissions from intact leaves capturing information associated with: (1) rate of emission; (2) the relative contribution of recently fixed carbon to isoprene biosynthesis; and (3) the transit time for tracer movement through the leaf and biochemical pathways associated with isoprene biosynthesis. This approach was applied to study the response of certain Populus species to exogenous treatments of jasmonic acid (JA), a plant hormone implicated in signal transduction linked to defence response against herbivory. Twelve hours after treatment of single intact leaves of aspen (Populus tremuloides) with a 1 m m JA spray, isoprene emissions from those leaves increased 1.5 times the controls from 35.4 ± 2.2 to 53.1 ± 4.8 nmol m−2 s−1. [11C]Isoprene emissions from the same leaves, reflecting the isoprene that was derived from recently fixed carbon, increased much more, to 2.2 times the controls. This increase coincided with a change in emitted [11C]isoprene from 0.31 to 0.68% of 11C fixed in the leaf tissue, while the tracer transit time remained constant at 12.5 min. These results suggest that JA had no effect on enzyme kinetics involved in isoprene biosynthesis, but did impact the source of recent carbon feeding that pathway. Studies with poplar (Populus nigra clone NC 5271) showed similar trends in systemic emissions (from an untreated leaf on the same plant).