bluuebunny/crossref_metadata_2025_split huggingface dataset:
Plant growth forms: an ecological and evolutionary perspective
Authors: Rowe Nick , Speck Thomas 
Published: March 2005

SummaryTrees, shrubs, lianas and herbs have widely different mechanical architectures, which can also vary phenotypically with the environment. This review investigates how environmental effects, particularly mechanical perturbation, can influence biomechanical development in self‐supporting and climbing growth forms. The bifacial vascular cambium is discussed in terms of its significance to growth form variation, ecology and evolution among extant plants, and during its appearance and early evolution. A key aspect of this developmental innovation concerned its potential for architectural and mechanical variation in response to environmental effects as well as optimizing hydraulic supply before the appearance of laminate leaves. Growth form diversity and its importance to past and present ecosystems are discussed in relation to both evolutionary constraints and ecological factors such as climatic change and atmospheric CO2 concentrations. We discuss how widely ranging growth forms such as climbers show a large range of developmental and phenotypic variation that has much to offer in understanding how the environment can modify plant development, particularly in terms of the bifacial vascular cambium. The broad approach we propose would benefit a wide range of studies from research into wood development to long‐term ecological censuses of today's potentially changing ecosystems.
Maternal effects provide phenotypic adaptation to local environmental conditions
Authors: Galloway Laura F. 
Published: March 2005

SummaryIn outcrossing plants, seed dispersal distance is often less than pollen movement. If the scale of environmental heterogeneity within a population is greater than typical seed dispersal distances but less than pollen movement, an individual's environment will be similar to that of its mother but not necessarily its father. Under these conditions, environmental maternal effects may evolve as a source of adaptive plasticity between generations, enhancing offspring fitness in the environment that they are likely to experience. This idea is illustrated usingCampanula americana, an herb that grows in understory and light‐gap habitats. Estimates of seed dispersal suggest that offspring typically experience the same light environment as their mother. In a field experiment testing the effect of open vs understory maternal light environments, maternal light directly influenced offspring germination rate and season, and indirectly affected germination season by altering maternal flowering time. Results to date indicate that these maternal effects are adaptive; further experimental tests are ongoing. Evaluating maternal environmental effects in an ecological context demonstrates that they may provide phenotypic adaptation to local environmental conditions.
Plant eco‐devo: the potential of poplar as a model organism
Authors: Cronk Q. C. B. 
Published: March 2005

SummaryEcological developmental genetics is the study of how ecologically significant traits originate in the genome and how the allelic combinations responsible are maintained in populations and species. Plant development involves a continuous feedback between growth and environment and the success of individual genotype × environment interactions determines the passage of alleles to the next generation: the adaptive recursion. Outbreeding plants contain a large amount of genetic variation, mostly in the form of single nucleotide polymorphisms (SNPs). One of the challenges of eco‐devo is to distinguish neutral SNPs from those with ecological consequences. The complete genome sequence of Populus trichocarpa Torr. & A. Gray will be a significant aid in this endeavour. Occurring from California to Alaska, this is the first ecologically ‘keystone’ species to be sequenced. It has a rich natural history and is an obligate outbreeder. The individual sequenced, Nisqually‐1, appears to be heterozygous on average about every 100 bp over the c. 500 million bp of the genome. Overlaid on this within‐individual variation is some ecologically based between‐individual genotypic variation evident across the distribution of the species. The synthesis of information from genomics and ecology is now in prospect. This ‘ecomolecular synthesis’ is likely to provide a rich insight into the genomic basis of plant adaptation.
Does Continuity of Care Matter in a Universally Insured Population?
Authors: Menec Verena H. , Sirski Monica , Attawar Dhiwya 
Published: March 2005

Objective.To examine the relation between continuity of care and preventive health care and emergency department (ED) use in a universal health care system.Data Sources/Study Setting.Administrative data that capture health care use of the entire population of a midwestern Canadian city.Study Design.A population‐based, retrospective study of all individuals who had a least one physician contact in 1998 or 1999 (totalN=536,893).Methods.Logistic regressions were conducted to examine the relation between continuity of care, defined in terms of the proportion of total visits to family physicians (FPs) made to the same FP, and cervical cancer screening, breast cancer screening, influenza vaccination, pneumococcal vaccination, and ED visits, controlling for demographic variables, socioeconomic status (defined in terms of relative affluence of neighborhood of residence), and health status.Principal Findings.Continuity of care was related to better preventive health care and reduced ED use. A consistent socioeconomic gradient also emerged. For instance, the odds of having a mammogram was double for individuals living in the wealthiest neighborhoods, relative to those in the poorest neighborhoods (adjusted odds ratio=2.31, 99 percent CI 2.13–2.50).Conclusions.Having a long‐term relationship with a single physician makes a difference even in a universal health care system. Moreover, socioeconomic disparities remain, suggesting the need to target specifically individuals from lower socioeconomic strata for preventive health care.
Determination of P50 for feline hemoglobin
Authors: Herrmann Katja , Haskins Steve 
Published: March 2005

AbstractObjective: The objective of this study was to determine the PO2 at 50% hemoglobin oxygenation (P50) of feline hemoglobin (Hb).Design: Prospective in vitro laboratory study.Setting: Research laboratory.Animals: Blood from 10 healthy cats.Interventions: Individual blood samples were equilibrated with calibrated gases of 95, 21, 8, 5, 4, and 2.5% oxygen for tonometric analysis.Measurements: Partial pressure of oxygen (PO2), oxygen content, oxyhemoglobin saturation, methemoglobin (MetHb), carboxyhemoglobin (COHb), Hb, packed cell volume, hydrogen ion concentration (pH), and partial pressure of carbon dioxide (PCO2) were measured in duplicate for each blood sample by tonometry. The P50 was calculated from both PO2/oxyhemoglobin saturation and PO2/oxygen content (per gram of Hb) curves.Main results: The P50 from the PO2/oxyhemoglobin saturation curve was 35.6 mmHg and from the PO2/oxygen content (per gram of Hb) curve was 36.2 mmHg.Conclusions: The oxyhemoglobin dissociation curve for the cat is shifted to the right, and thus, feline Hb has lower oxygen affinity compared with human and canine Hb.
Characteristics of a Clinical Isolate of Urease‐Negative Helicobacter pylori and its Ability to Induce Gastric Ulcers in Mongolian Gerbils
Authors: Mine Tetsuya , Muraoka Hiroe , Saika Takeshi , Kobayashi Intetsu 
Published: March 2005

ABSTRACTBackground.  We clinically obtained urease‐negative mutant strains of Helicobacter pylori. The goal of this study was to investigate the ability of the urease‐negative strain to colonize and subsequently damage the gastric mucosa in Mongolian gerbils. In addition, the genes encoding the urease production in the test strain were analyzed, and other genes encoding the virulence factors, cytotoxin‐associated protein and vacuolating‐cytotoxin were evaluated.Materials and methods.  The character of urease‐negative isolates of H. pylori was defined. The identification of H. pylori was confirmed by polymerase chain reaction (PCR). The H. pylori isolate was transfected into Mongolian gerbils as previously described, which were followed up to 42 weeks, and the changes in their gastric mucosa were examined histologically.Results and conclusion.  Fifteen Mongolian gerbils orally infected with 107 colony forming units of urease‐negative H. pylori were killed at 4, 12, 24, 36 and 42 weeks (n = 3) after infection. Culture medium without urease‐negative H. pylori was given to the Mongolian gerbils as control. H. pylori continued to exist in the subject's stomach and gastric ulceration was observed and compared with the control. Clinically obtained urease‐negative H. pylori continued to exist for at least 42 weeks in the subject's stomach and it induced gastric ulcers. These data demonstrated that the urease in H. pylori was not a necessary factor in the formation of gastric ulcers in the Mongolian gerbil model.
Degradation of tyrosinase induced by phenylthiourea occurs following Golgi maturation
Authors: Hall Andrea M. , Orlow Seth J. 
Published: March 2005

SummaryTyrosinase, the rate‐limiting enzyme of melanin synthesis, is a di‐copper metalloprotein that catalyzes the conversion of l‐tyrosine to l‐DOPAquinone. Phenylthiourea (PTU) is a well‐known inhibitor of tyrosinase and melanin synthesis and is known to interact with sweet potato catechol oxidase, an enzyme possessing copper binding domain homology to tyrosinase. While PTU is frequently used to induce hypopigmentation in biological systems, little is known about its effects on tyrosinase and other melanogenic proteins. We have found that PTU induces degradation of tyrosinase but not of other melanogenic proteins including the tyrosinase‐related metalloproteins tyrosinase‐related protein (Tyrp)1 and Tyrp2. Using pulse‐chase analysis coupled with glycosidase digestion, we observed that tyrosinase degradation occurs following complete maturation of the protein and that degradation was reversed by cysteine protease inhibitor E64 but not proteasome inhibitor N‐acetyl‐l‐leucinyl‐l‐leucinyl‐l‐norleucinal. We conclude that PTU specifically induces tyrosinse degradation following Golgi maturation. Our data suggest that in addition to well‐known ER‐directed quality control, tyrosinase is also subject to post‐Golgi quality control.
Human placental lipid induces melanogenesis through p38 MAPK in B16F10 mouse melanoma
Authors: Singh Suman Kumar , Sarkar Chinmoy , Mallick Shampa , Saha Bidisha , Bera Rabindranath , Bhadra Ranjan 
Published: March 2005

SummaryMelanogenesis is one of the characteristic functional activities of melanocyte/melanoma and is regulated via mitogen‐activated protein kinase (MAPK) and Akt/protein kinase B (PKB) pathways. Placental total lipid fraction (PTLF), prepared from a hydroalcoholic extract of fresh term human placenta contains sphingolipids and was recently shown to stimulate melanogenesis via up‐regulation of the key enzyme tyrosinase in B16F10 mouse melanoma cells. How such lipids mediate their effects on pigmentation and tyrosinase expression is a particularly important aspect of melanogenesis. To study the signaling that leads to tyrosinase expression, we have investigated the roles of the MAPK and Akt/PKB pathways in B16F10 melanoma cells in melanogenesis in response to PTLF. Treatment of cells with PTLF led to the time dependent phosphorylation of p38 MAPK. SB203580, a p38 MAPK inhibitor, completely blocked the PTLF‐induced melanogenesis by inhibiting promoter activity and subsequent expression of tyrosinase. Phosphatidylinositol 3‐kinase (PI3K) inhibitor, LY294002 a blocker of the Akt signaling pathway, or an inhibitor of MEK (MAPK/ERK Kinase), PD98059 when included along with PTLF was found to potentiate PTLF‐induced phosphorylation of p38 MAPK together with tyrosinase expression and melanogenesis. The results suggest that the activation of p38 MAPK plays a crucial role in PTLF‐induced B16F10 melanogenesis by up‐regulating tyrosinase expression.
Experimental Genital Mycoplasmosis Causes Increased Levels of mRNA for IL‐6 and TNF‐α in the Placenta
Authors: Peltier Morgan R. , Brown Mary B. 
Published: March 2005

Problem:  Previous studies with animal models have shown that injection of lipopolysaccharide (LPS) results in fetal loss and increases production of proinflammatory cytokines at the maternal–fetal interface. Most intrauterine infections, however, are associated with Ureaplasma urealyticum, a microorganism that lacks a cell wall and therefore does not contain LPS. Previous work in our laboratory with an animal model for genital infection with a similar organism, Mycoplasma pulmonis, revealed that widespread infection in maternal and fetal tissues can be experimentally induced with minimal manipulation of the animal. For this project, we tested the hypothesis that administration of the organism by a hematogenous route at gestational day (gd) 14 would result in increased tumor necrosis factor (TNF)‐α and interleukin (IL)‐6 production by the placenta.Study design:  Timed‐pregnant, Sprague–Dawley rats were anesthetized on gd 14 and 107 CFU of M. pulmonis strain X1048 or an equivalent volume of sterile medium was injected into the heart. Rats were necropsied on gd 18 or 21, and ex vivo production of TNF‐α and IL‐6 was evaluated from six randomly selected placentas from each litter. The remaining placentas were harvested and either snap‐frozen or placed in formalin. Frozen placentas were processed for real‐time reverse transcriptase‐polymerase chain reaction (RT‐PCR) analysis of TNF‐α and IL‐6 mRNA. Formalin‐fixed placentas were sectioned and stained with hematoxylin and eosin for lesion analysis.Results:  Concentrations of TNF‐α but not IL‐6 were significantly higher in conditioned medium from placentas harvested from infected dams at gd 21. Levels of mRNA for IL‐6 and TNF‐α, however, were increased by M. pulmonis at gd 18 and 21. Analysis of gd 21 placentas by light microscopy revealed that significant histological chorioamnionitis was present in infected animals with accumulations of neutrophils in the capsular decidua.Conclusion:  These data indicate that experimental infection with M. pulmonis causes histological chorioamnionitis, elevated mRNA levels of TNF‐α and IL‐6 in placental tissues, and the secretion of TNF‐α by the placenta during late gestation.
Volcanic and Solar Forcing of the Tropical Pacific over the Past 1000 Years
Authors: Mann Michael E. , Cane Mark A. , Zebiak Stephen E. , Clement Amy 
Published: March 2005

Abstract
The response of El Niño to natural radiative forcing changes over the past 1000 yr is investigated based on numerical experiments employing the Zebiak–Cane model of the tropical Pacific coupled ocean–atmosphere system. Previously published empirical results demonstrating a statistically significant tendency toward El Niño conditions in response to past volcanic radiative forcing are reproduced in the model experiments. A combination of responses to past changes in volcanic and solar radiative forcing closely reproduces changes in the mean state and interannual variability in El Niño in past centuries recorded from fossil corals. The dynamics of El Niño thus appear to have played an important role in the response of the global climate to past changes in radiative forcing.
Complementary role of CD4+CD25+ regulatory T cells and TGF-β in oral tolerance
Authors: Chung Yeonseok , Lee Seung-Ho , Kim Dong-Hyeon , Kang Chang-Yuil 
Published: March 2005

AbstractCD4+CD25+ regulatory T cells are thought to be generated in the periphery as well as in the thymus. We sought to determine the roles played by CD4+CD25+ T cells and transforming growth factor-β (TGF-β) in the induction and maintenance of tolerance generated by oral antigens in BALB/c mice. We found that oral administration of a high dose of ovalbumin (OVA) suppressed OVA-specific proliferation and antibody production in BALB/c mice depleted of CD25+ cells. In contrast, the unresponsiveness induced by lower doses of OVA was only partially blocked by CD25 depletion prior to feeding. Depletion of CD4+CD25+ cells after mice were orally tolerized did not reverse the tolerant status, indicating that these cells were not required to maintain the established tolerance. Furthermore, the induction of oral tolerance was not hampered by the administration of TGF-β-neutralizing antibodies. However, in mice depleted of CD25+ cells, anti-TGF-β-neutralizing antibodies blocked the induction of tolerance, regardless of whether the mice followed the high- or low-dose regimens of oral OVA. CD25 depletion together with TGF-β neutralization led the expansion of OVA-specific CD4 T cells against the subsequent antigen challenge, and each treatment alone did not. Our findings indicate that CD4+CD25+ T cells and TGF-β play a complementary role in the induction of oral tolerance, at least in part, by regulating the expansion of antigen-specific CD4 T cells.
Aminopeptidase N (CD13) functionally interacts with FcγRs in human monocytes
Authors: Mina-Osorio Paola , Ortega Enrique 
Published: March 2005

AbstractAminopeptidase N (E.C. 3.4.11.2) is a membrane-bound metalloproteinase expressed in many tissues. Although its cytoplasmic portion has only eight amino acids, cross-linking of CD13 by monoclonal antibodies (mAb) has been shown to trigger intracellular signaling. A functional association between CD13 and receptors for immunoglobulin G (FcγRs) has been proposed. In this work, we evaluated possible functional interactions between CD13 and FcγRs in human peripheral blood monocytes and in U-937 promonocytic cells. Our results show that during FcγR-mediated phagocytosis, CD13 redistributes to the phagocytic cup and is internalized into the phagosomes. Moreover, modified erythrocytes that interact with the monocytic cell membrane through FcγRI and CD13 are ingested simultaneously, more efficiently than those that interact through the FcγRI only. Also, co-cross-linking of CD13 with FcγRI by specific mAbs increases the level and duration of Syk phosphorylation induced by FcγRI cross-linking. Finally, FcγRI and CD13 colocalize in zones of cellular polarization and coredistribute after aggregation of either of them. These results demonstrate that CD13 and FcγRI can functionally interact on the monocytic cell membrane and suggest that CD13 may act as a signal regulator of FcγR function.
Laboratory Calibration of Earth Pressure Cells
Authors: Labuz JF , Theroux B 
Published: March 2005

Abstract
The objective of this study was to design a simple apparatus for laboratory calibration of diaphragm type earth pressure cells (EPC). A new testing device was fabricated to permit the application of normal stress to the EPC using various types of soil and load configurations. With respect to fluid pressure, the response of the EPC can be different for the simplest earth pressure conditions because of an arching effect or nonuniform contact stress. For an EPC with a rigid outer rim, sensitivities computed from soil calibrations were lower than those determined from fluid calibrations by about 20 %.
P-Wave Reflection Imaging
Authors: Lee J-S , Carlos Santamarina J 
Published: March 2005

Abstract
The reflection of elastic waves from interfaces is a robust phenomenon extensively used by animals (bats and dolphins), nondestructive techniques, and medical diagnosis. This study addresses the design and implementation of P-wave reflection imaging to evaluate the internal variability in small-scale submerged, soil models. The performance of this technology depends on fundamental aspects of P-wave propagation in soils, the selection of optimal P-wave transducers, and the development of an adequate test methodology. Design issues include transducer directivity, noise, axial resolution, near field effects, and proper thickness of the coupling water layer. The operating frequency is determined by transducer selection and affects the axial and lateral resolution, skin depth, near field, and divergence; high damping transducers permit higher axial resolution. In addition, data gathering must take into consideration temporal and spatial aliasing. Results show that P-wave reflection is a valuable tool to detect subsurface anomalies and layers, to assess phenomena such as slurry sedimentation, and to monitor the evolution of subsurface structures such as soil layers during liquefaction. Gradual changes in impedance, such as in slurry sedimentation, may prevent reflections.
Characterization of Crack Length Measurement Methods for Flat Fracture with Tunneling
Authors: James MA , Newman JC 
Published: March 2005

AbstractThis paper compares area-average and unloading compliance crack-growth values with experimental crack-front shapes recorded at various stages of crack growth during fracture tests conducted on 2024-T351 aluminum alloy plate. Crack-front shapes were determined by fracturing the specimen up to a predetermined amount of crack growth and fatigue cycling the specimen for about 4000 cycles at a high stress ratio to mark the crack-front location. For each shape, the area-average and unloading compliance crack lengths were determined. Boundary collocation results provide an approximation to the δ5 unloading compliance crack length. The crack tunneling results show that the area-average technique produces crack-length measurements more representative of the straight-front finite element analyses than optical based surface measurements. The δ5 technique is significantly more sensitive to tunneling than the CMOD technique and is easier to apply than the area-average technique.
Identification of a Physical Model to Evaluate Rutting Performance of Asphalt Mixtures
Authors: Drakos CA , Roque R , Birgisson B , Novak M 
Published: March 2005

Abstract
The objective of this study is to identify a physical model that can provide reliable predictions about a mixture's ability to resist permanent deformation under realistic stress states. Key differences were identified between stress states under the existing Asphalt Pavement Analyzer (APA) loading device (hose) and stress states under radial truck tires, which may indicate potentially different rutting mechanisms. It was shown that the APA hose was not capturing the critical lateral stresses found to be detrimental to rutting and cracking of HMA pavements. A new loading device (rib) was designed and constructed for use in the APA that more closely represents stress states found under radial tires.
Contact-stress measurements under the two loading devices — hose and rib — showed that the rib was able to reproduce the lateral stresses found under individual ribs on a radial-tire tread. Subsequent finite element modeling also showed that the rib appeared to generate similar shear stress patterns to those found under the modeled radial-tire load.
A new method was developed to measure deformations on the surface of APA specimens, where a contour gauge was used to record and store the entire surface profile of the sample throughout the progress of the test. An area-change parameter, which reflects volume change, was introduced to calculate the volumetric changes in the specimen. The area-change parameter can be used to determine whether specimen rutting is primarily due to shear instability or consolidation.
Two mixtures of known field performance — poor and good — were tested to evaluate the test's ability to predict performance with the new loading device and the new measurement and interpretation system. Results showed that the new system (loading strip and profile measurement method) appears to have greater potential of evaluating a mixture's potential for instability rutting than the original (hose and single rut-depth measurement) configuration.