170,303 research outputs found
Impact of cadmium on young plants of Populus euphratica and P. × canescens, two poplar species that differ in stress tolerance
No full textPopulus euphratica is a salt tolerant species, and Populus × canescens is a salt sensitive species. Because stress tolerance is mediated by an array of overlapping defense mechanisms, we hypothesized that P. euphratica would confer co-tolerance to heavy metal stress. To test this hypothesis, both poplar species were exposed to 50 μM Cd for 24 h in hydroponic solutions. For the analyses of stress symptoms in roots and leaves, we used nutrient element concentrations and transcriptional responses of 28 stress- and defense-related genes. The roots showed strong Cd accumulation, but less in P. euphratica than in P. × canescens. In contrast, the leaves of P. euphratica accumulated 10-times more Cd than those of P. × canescens. Cd-stressed leaves of P. euphratica displayed water loss and wilting. Both species revealed contrasting transcriptional responses of defense genes to Cd stress. In P. euphratica, glutathione reductase, dehydroascorbate reductase and glutathione S-transferases of the theta and tau classes showed increases in transcript levels in response to Cd, pointing to oxidative stress and a strong activation of detoxification mechanisms. In contrast, in P. × canescens transcript levels of genes involved in signaling, activation of, and protection from drought stress were significantly increased including glutathione S-transferases of the phi class (early response to dehydration). Our data show that P. euphratica salt tolerance does not confer Cd tolerance and suggest that failure to activate early protection contributed to higher Cd sensitivity in P. euphratica than in P. × canescens
William and Marion Kettner: Brother Bill and the Lass From Tuolumne
No full textThe presence and financial impact of the United States Navy upon the city and county of San Diego cannot be disputed. The person responsible in large part for this impact was Congressman William Kettner, whose vision, foresight, and singleminded devotion to the city was legendary in his time. Little is known today of this outstanding citizen save a main thoroughfare, Kettner Boulevard, named in the Congressman\u27s honor in 1921. Yet this man, among other accomplishments, brought the Navy to San Diego, which today claims one out of every three county residents as either active duty, retired, a member of the reserve, a dependent, or civilian employee.
At his side, always giving gentle support, stood Kettner\u27s second wife, Marion. Unique because of her marriages to two prominent San Diegans during her lifetime, Marion Kettner\u27s story has merit in itself. This quiet, unassuming yet brilliant woman served often as the source of Kettner\u27s inspiration.
William and Marion Kettner moved to San Diego in 1907 from the small town of Visalia in central California. Kettner established an insurance agency and soon, by virtue of his magnetic personality, became everyone\u27s friend. San Diego of 1907 consisted of 38,000 people. The local scene was dominated by such figures as John D. Spreckels, D. C. Collier, Alonzo E. Horton, George White Marston, and Colonel Ed Fletcher.
Kettner became obsessed with the idea of promoting San Diego\u27s virtues. His election to Congress, in what could be called a fluke of politics, and after only five years\u27 residence in the city, triggered the career which was to absorb him to the end of his life in 1930. For the next eighteen years Kettner\u27s every waking thought was of the city he loved, of expanding its harbor, its economy, and putting San Diego on the map.
Kettner\u27s phenomenal record as a congressman, in a district composed of seven counties comprising 49,000 square miles, his unique method of approaching politics as a businessman, had great impact upon the growth of San Diego. Kettner\u27s popularity grew until some talked of the possibility of his becoming a senator, perhaps even president of the United States. His fame spread, and with it, San Diego\u27s as well.
William Kettner\u27s life was one of ambition, determination, and the fulfillment of the American dream. Marion\u27s role, although less well known, is equally important. Their story, as a team, deserves to be remembered in the history of San Diego
pH influence on root growth and nutrient uptake of Pinus pinaster seedlings
No full textTwo-week old Pinus pinaster seedlings were grown at four pH values ranging from 3.5 to 6.5. Root elongation rate progressively decreased with the duration of treatment at 3.5 and 6.5 pH. After 4 weeks 3.5 pH grown roots showed the lowest length and the highest biomass because of their marked thickening. The pH of the culture solution did not influence lateral root initiation, whereas it affected their length, that was highest at 3.5 pH and lowest at 6.5 pH. Mineral nutrition was affected by the pH of the culture solution. The P, Fe and Al concentration in roots was higher in the 3.5 and 4.5 pH solutions. On the contrary, a lower K, Ca, Mg and especially Mn content of roots was measured in the 3.5 pH grown seedlings. These results suggest that P. pinaster is able to grow on a wide range of acidic soils changing the morphology of the root system in relation to soil conditions
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Insulin potentiates FcepsilonRI-mediated signaling in mouse bone marrow-derived mast cells.
No full textFactors contained in physiological microenvironments in tissues where mast cells differentiate and reside may influence mast cell responsiveness and modify antigen-dependent activation. A possible direct or indirect role of mast cell responses in diabetes mellitus prompted us to study the impact of insulin treatment on antigen triggered signaling pathways downstream of FcepsilonRI in bone marrow-derived mouse mast cells (BMMCs). We found that insulin alone stimulates tyrosine phosphorylation of tyrosine kinases Lyn, Syk, Fyn, the adapter protein Gab2 (Grb2-associated binding protein 2), Akt and activates ERK, JNK and p38 kinase. Effect of insulin on FcepsilonRI signaling pathways was marked by enhanced phosphorylation of Lyn, Fyn, Gab2 and Akt. Furthermore, BMMC stimulated with antigen in the presence of insulin responded with enhanced protein kinase theta (PKCtheta) activity and increased JNK phosphorylation when compared to BMMC triggered with antigen alone. Functional studies reveal enhanced degranulation and altered cytoskeletal rearrangement when BMMCs were treated simultaneously with insulin and antigen. Our results suggest that insulin tunes antigen-mediated responses of mast cells. (c) 2009 Elsevier Ltd. All rights reserved
JWS online: a web-based tool for curation, review, sotrage and analysis of kinetic models.
No full textMitomycin C in highly myopic eyes - Author reply
No full textOphthalmology. 2005 Feb;112(2):208-18; discussion 219.
Mitomycin C modulation of corneal wound healing after photorefractive keratectomy in highly myopic eyes.
Gambato C, Ghirlando A, Moretto E, Busato F, Midena E.
SourceRefractive Surgery Service and Antimetabolite Therapy Research Unit, Department of Ophthalmology, University of Padova, Padova, Italy.
Abstract
PURPOSE: To evaluate the role of topical mitomycin C in corneal wound healing (CWH) after photorefractive keratectomy (PRK) in highly myopic eyes.
DESIGN: Prospective, double-masked, randomized clinical trial.
PARTICIPANTS: Seventy-two eyes of 36 patients affected by high (>7 diopters) myopia.
METHODS: In each patient, one eye was randomly assigned to PRK with intraoperative topical 0.02% mitomycin C application, and the fellow eye was treated with a placebo. Postoperatively, mitomycin C-treated eyes received artificial tears (3 times daily, tapered in 3 months), whereas the fellow eye was treated with fluorometholone sodium 2% and artificial tears (3 times daily, tapered in 3 months).
MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA), contrast sensitivity, manifest refraction, and biomicroscopy. Contrast sensitivity was determined using the Pelli-Robson chart. Corneal confocal microscopy documented CWH.
RESULTS: Mean follow-up was 18 months (range, 12-36). No side effects or toxic effects were documented. At 12-month follow-up examination, UCVAs (logarithm of the minimum angle of resolution) were 0.4+/-0.48 and 0.5+/-0.53 (P = .03) in mitomycin C-treated eyes and corticosteroid-treated eyes, respectively. At 1 year, corneal haze developed in 20% of corticosteroid-treated eyes, versus 0% of mitomycin C-treated eyes. At 12, 24, and 36 months, corneal confocal microscopy showed activated keratocytes and extracellular matrix significantly more evident in untreated eyes (Ps = 0.004, 0.024, and 0.046, respectively).
CONCLUSION: Topical intraoperative application of 0.02% mitomycin C can reduce haze formation in highly myopic eyes undergoing PRK.
Comment in
Ophthalmology. 2006 Feb;113(2):357; author reply 357-8
AMČR - dokument C-TX-200600276
No full textStav: 3Označení: TP200600276Popis: Objevy pozůstatků člověka.Poznámka: Článek pro chystanou publikaci (red. Kettner)
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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