1,114 research outputs found
The interaction of gibberellic acid and 2-(chloroethyl) trimethyl ammonium chloride on fruit cluster development in Vitis vinifera L.
The effects of applications of GA and CCC in factorial combinations and at different stages of development were measured on reproductive development of five cultivars of Vitis vinifera: Doradillo and Muscat (seeded), Sultana (stenospermocarpic), and Cape Currant and Zante Currant (parthenocarpic). The effect of GA on fruit set varied with concentration, stage of development when applied, and the cultivar, that is whether seeded, stenospermocarpic, or parthenocarpic. Set was decreased in the parthenocarpic cultivars by GA applied before anthesis; other timings were without effect. On Sultana, set was decreased by GA applied at anthesis but was increased by earlier or later applications. With the seeded cultivars, GA reduced the number of seeded berries but increased the number of seedless berries, the net effect being usually an increase. The application of CCC two weeks. before anthesis generally increased set. The amount of seed development also influenced the effect of GA on berry fresh weight; seeded berries were unaffected but seedless berries were usually enlarged. The enlargement was greatest in parthenocarpic berries especially when treated at anthesis. On stenospermocarpic berries, treatment two weeks after anthesis had the greatest effect. CCC reduced berry size whether applied before or after anthesis; the reductions ranged from 2 to 20 per cent.GA increased the length/width ratio of berries, particularly when applied at anthesis, but the amount of change depended on the cultivar. CCC reduced the length/width ratio of Sultana berries. The effects of GA and CCC on rachis elongation were also opposite: GA increased the length of the rachis and pedicel, particularly if applied before anthesis; CCC reduced their length.There were few instances where GA and CCC interacted significantly; their effects within the concentration ranges chosen were generally additive.Der EinfluĂ von GibberellinsĂ€ure und CCC auf die Traubenentwicklung bei Vitis vinifera L.Der EinfluĂ von GibberellinsĂ€ure (GS)- und CCC-Gaben in faktorieller Kombination und in verschiedenen Entwicklungsphasen auf die generative Entwicklung der fĂŒnf Vitis vinifera-Sorten Doradillo und Muskat (samenhaltig), Sultana (stenospermokarp), Cape Currant und Zante Currant (parthenokarp) wurde gemessen. Der EinfluĂ der GS auf den Fruchtansatz hing von der Konzentration, dem Entwicklungsstadium zur Zeit der Applikation und von der Sorte ab, d. h. ob samenhaltig, stenospermokarp oder parthenokarp. Vor der Anthesis angewendet, verminderte GS den Fruchtansatz; spĂ€tere Anwendungen waren ohne Wirkung. Bei Sultana verminderte GS den Fruchtansatz, wenn sie zur BlĂŒtezeit, und erhöhte ihn, wenn sie vorher oder nachher appliziert wurde. Bei den samenhaltigen Sorten verminderte GS die Zahl der samenhaltigen und erhöhte die der samenlosen Beeren; die Gesamtzahl der Beeren war gewöhnlich vergröĂert. Die Anwendung von CCC zwei Wochen vor dem BlĂŒhen erhöhte allgemein den Fruchtansatz.Ăber die Samenentwicklung beeinfluĂte GS auch das Frischgewicht der Beeren; samenhaltige Beeren lieĂen keine Wirkung erkennen, wĂ€hrend samenlose meistens vergröĂert waren, und zwar am stĂ€rksten bei parthenokarpen Beeren, besonders nach Behandlung wĂ€hrend der Anthesis. Bei stenospermokarpen Beeren hatte die zwei Wochen nach der BlĂŒtezeit applizierte GS die gröĂte Wirkung. CCC, vor oder nach dem AufblĂŒhen angewendet, verminderte die BeerengröĂe; der RĂŒckgang betrug 2-20%. Durch GS wurde - sortenabhĂ€ngig - das VerhĂ€ltnis LĂ€nge/Breite der Beeren vergröĂert, besonders bei Anwendung wĂ€hrend der Anthesis. CCC verminderte dieses VerhĂ€ltnis bei Sultana-Beeren. Auch das Wachstum des Traubenstieles wurde durch GS und CCC gegensĂ€tzlich beeinfluĂt; GS förderte das LĂ€ngenwachstum von Traubenund Beerenstielen, besonders bei Anwendung vor der BlĂŒte; CCC verminderte es. In einigen FĂ€llen beeinfluĂten sich GS und CCC gegenseitig signifikant; im allgemeinen wurden hierdurch bei den verwendeten Konzentrationen ihre Wirkungen gesteigert
Gibberellic acid, chlorocholine chloride and yield increases in Zante currant
GA and CCC additively increased yield of Zante currant fruit. GA induced an increase in berry size (weight and volume) which was unaffected by CCC, while CCC offset to an appreciable extent the reduction in berry number associated with low concentrations of GA
Hydrogen Cyanamide Causes Reversible G2/M Cell Cycle Arrest Accompanied by Oxidation of the Nucleus and Cytosol
Hydrogen cyanamide (HC) has been widely used in horticulture to trigger bud burst following dormancy. Its use has been banned in some countries due to human health concerns, however the search for effective safe alternatives is delayed by lack of knowledge of the mechanism of HC action. Earlier studies demonstrate that HC stimulates the production of reactive oxygen species (ROS) and alters the rate of cell division. However, the relationships between HC effects on ROS, redox (reduction/oxidation) homeostasis and cell division are unknown. This study used Arabidopsis thaliana ((L.) Heynh.) seedlings expressing the redox reporter roGFP2 to measure the oxidation states of the nuclei and cytosol in response to HC treatment. The Cytrap dual cell cycle phase marker system and flow cytometry were used to study associated changes in cell proliferation. HC (1.5 mM) reversibly inhibited root growth during a 24 h treatment. Higher concentrations were not reversible. HC did not synchronise the cell cycle, in contrast to hydroxyurea. Rather, HC caused a gradual accumulation of cells in the G2/M phase and decline of G1/S phase cells, 16 to 24 h post-treatment. This was accompanied by increased oxidation of both the nuclei and cytosol. Taken together, these findings show that HC impairs proliferation of embryonic root meristem cells in a reversible manner through restriction of G2/M transition accompanied by increased cellular oxidation
Combination GLP-1 and Insulin Treatment Fails to Alter Myocardial Fuel Selection Versus Insulin Alone in Type 2 Diabetes
Context
Glucagon-like peptide-1 (GLP-1) and the clinically available GLP-1 agonists have been shown to exert effects on the heart. It is unclear whether these effects occur at clinically used doses in vivo in humans, possibly contributing to CVD risk reduction.
Objective
To determine whether liraglutide at clinical dosing augments myocardial glucose uptake alone or in combination with insulin compared to insulin alone in metformin-treated Type 2 diabetes mellitus.
Design
Comparison of myocardial fuel utilization after 3 months of treatment with insulin detemir, liraglutide, or combination detemir+liraglutide.
Setting
Academic hospital
Participants
Type 2 diabetes treated with metformin plus oral agents or basal insulin.
Interventions
Insulin detemir, liraglutide, or combination added to background metformin
Main Outcome Measures
Myocardial blood flow, fuel selection and rates of fuel utilization evaluated using positron emission tomography, powered to demonstrate large effects.
Results
We observed greater myocardial blood flow in the insulin-treated groups (median[25th, 75th percentile]: detemir 0.64[0.50, 0.69], liraglutide 0.52[0.46, 0.58] and detemir+liraglutide 0.75[0.55, 0.77] mL/g/min, p=0.035 comparing 3 groups and p=0.01 comparing detemir groups to liraglutide alone). There were no evident differences between groups in myocardial glucose uptake (detemir 0.040[0.013, 0.049], liraglutide 0.055[0.019, 0.105], detemir+liraglutide 0.037[0.009, 0.046] ”mol/g/min, p=0.68 comparing 3 groups). Similarly there were no treatment group differences in measures of myocardial fatty acid uptake or handling, and no differences in total oxidation rate.
Conclusions
These observations argue against large effects of GLP-1 agonists on myocardial fuel metabolism as mediators of beneficial treatment effects on myocardial function and ischemia protection
Kinetics of catalysis with surface disorder
We study the effects of generalised surface disorder on the monomer-monomer
model of heterogeneous catalysis, where disorder is implemented by allowing
different adsorption rates for each lattice site. By mapping the system in the
reaction-controlled limit onto a kinetic Ising model, we derive the rate
equations for the one and two-spin correlation functions. There is good
agreement between these equations and numerical simulations. We then study the
inclusion of desorption of monomers from the substrate, first by both species
and then by just one, and find exact time-dependent solutions for the one-spin
correlation functions.Comment: LaTex, 19 pages, 1 figure included, requires epsf.st
Correlation between Ventromedial Prefrontal Cortex Activation to Food Aromas and Cue-driven Eating: An fMRI Study
Food aromas are signals associated with both food's availability and pleasure. Previous research from this laboratory has shown that food aromas under fasting conditions evoke robust activation of medial prefrontal brain regions thought to reflect reward value (Bragulat, et al. 2010). In the current study, eighteen women (eleven normal-weight and seven obese) underwent a two-day imaging study (one after being fed, one while fasting). All were imaged on a 3T Siemens Trio-Tim scanner while sniffing two food (F; pasta and beef) odors, one non-food (NF; Douglas fir) odor, and an odorless control (CO). Prior to imaging, participants rated hunger and perceived odor qualities, and completed the Dutch Eating Behavior Questionnaire (DEBQ) to assess âExternalityâ (the extent to which eating is driven by external food cues). Across all participants, both food and non-food odors (compared to CO) elicited large blood oxygenation level dependent (BOLD) responses in olfactory and reward-related areas, including the medial prefrontal and anterior cingulate cortex, bilateral orbitofrontal cortex, and bilateral piriform cortex, amygdala, and hippocampus. However, food odors produced greater activation of medial prefrontal cortex, left lateral orbitofrontal cortex and inferior insula than non-food odors. Moreover, there was a significant correlation between the [F > CO] BOLD response in ventromedial prefrontal cortex and âExternalityâ sub-scale scores of the DEBQ, but only under the fed condition; no such correlation was present with the [NF > CO] response. This suggests that in those with high Externality, ventromedial prefrontal cortex may inappropriately valuate external food cues in the absence of internal hunger
Adipocytes enhance murine pancreatic cancer growth via a hepatocyte growth factor (HGF)-mediated mechanism
INTRODUCTION:
Obesity accelerates the development and progression of pancreatic cancer, though the mechanisms underlying this association are unclear. Adipocytes are biologically active, producing factors such as hepatocyte growth factor (HGF) that may influence tumor progression. We therefore sought to test the hypothesis that adipocyte-secreted factors including HGF accelerate pancreatic cancer cell proliferation.
MATERIAL AND METHODS:
Murine pancreatic cancer cells (Pan02 and TGP-47) were grown in a) conditioned medium (CM) from murine F442A preadipocytes, b) HGF-knockdown preadipocyte CM, c) recombinant murine HGF at increasing doses, and d) CM plus HGF-receptor (c-met) inhibitor. Cell proliferation was measured using the MTT assay. ANOVA and t-test were applied; p < 0.05 considered significant.
RESULTS:
Wild-type preadipocyte CM accelerated Pan02 and TGP-47 cell proliferation relative to control (59 ± 12% and 34 ± 12%, p < 0.01, respectively). Knockdown of preadipocyte HGF resulted in attenuated proliferation vs. wild type CM in Pan02 cells (35 ± 5% vs. 68 ± 14% greater than control; p < 0.05), but proliferation in TGP-47 cells remained unchanged. Recombinant HGF dose-dependently increased Pan02, but not TGP-47, proliferation (p < 0.05). Inhibition of HGF receptor, c-met, resulted in attenuated proliferation versus control in Pan02 cells, but not TGP-47 cells.
CONCLUSIONS:
These experiments demonstrate that adipocyte-derived factors accelerate murine pancreatic cancer proliferation. In the case of Pan02 cells, HGF is responsible, in part, for this proliferation
Participatory GIS as a Tool for Stakeholder Engagement in Building Resilience to Sea Level Rise: A Demonstration Project
This article describes a participatory geographical information system (PGIS) demonstration project used as part of the stakeholder engagement efforts undertaken by the Citizen Engagement Working Group of the Hampton Roads Sea Level Rise Preparedness and Resilience Intergovernmental Planning Pilot Project. The PGIS demonstration project was conducted in the Little Creek/Pretty Lake case study area in the Hampton Roads region of southeastern coastal Virginia. PGIS served as a deliberative and participatory mechanism to obtain local knowledge from residents about the location of valued assets within the community and locations challenged by increased flooding and sea level rise. The PGIS application, using the weTable tool, was found to be useful for soliciting and documenting local knowledge, such as by highlighting community assets and identifying community challenges. It was also found to be useful for facilitating community-wide discussion, visualizing the problem, and understanding the severity of sea level rise and flooding. The PGIS demonstration project showed how participatory mapping can directly engage residents in creating sociospatial data, build knowledge, and foster learning and deliberation in a complex issue such as resilience to flooding and sea level rise
Corner Exponents in the Two-Dimensional Potts Model
The critical behavior at a corner in two-dimensional Ising and three-state
Potts models is studied numerically on the square lattice using transfer
operator techniques. The local critical exponents for the magnetization and the
energy density for various opening angles are deduced from finite-size scaling
results at the critical point for isotropic or anisotropic couplings. The
scaling dimensions compare quite well with the values expected from conformal
invariance, provided the opening angle is replaced by an effective one in
anisotropic systems.Comment: 11 pages, 2 eps-figures, uses LaTex and eps
ExCEEd teaching workshop: Tenth year anniversary
In response to the need for faculty training, the American Society of Civil Engineers developed and funded the ExCEEd (Excellence in Civil Engineering Education) Teaching Workshop that is today â the summer of 2008 â celebrating its tenth year of existence. For the past decade, nineteen ExCEEd Teaching Workshops (ETW) have been held at the United States Military Academy, the University of Arkansas, and Northern Arizona University, with two more workshops scheduled for this summer for a total of 21 offerings. ETW has realized 449 graduates from 203 different U.S. and international colleges and universities. This paper summarizes the content of ETW, assesses its effectiveness, highlights changes in the program as a result of the assessment, and outlines future directions. The assessment data were obtained from multiple survey instruments conducted during each workshop, surveys taken six months to a year after the workshop, and a ten year longitudinal survey
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