232 resultados para Wendell
Resumo:
Microchip electrophoresis has become a powerful tool for DNA separation, offering all of the advantages typically associated with miniaturized techniques: high speed, high resolution, ease of automation, and great versatility for both routine and research applications. Various substrate materials have been used to produce microchips for DNA separations, including conventional (glass, silicon, and quartz) and alternative (polymers) platforms. In this study, we perform DNA separation in a simple and low-cost polyester-toner (PeT)-based electrophoresis microchip. PeT devices were fabricated by a direct-printing process using a 600 dpi-resolution laser printer. DNA separations were performed on PeT chip with channels filled with polymer solutions (0.5% m/v hydroxyethylcellulose or hydroxypropylcellulose) at electric fields ranging from 100 to 300Vcm(-1). Separation of DNA fragments between 100 and 1000 bp, with good correlation of the size of DNA fragments and mobility, was achieved in this system. Although the mobility increased with increasing electric field, separations showed the same profile regardless of the electric field. The system provided good separation efficiency (215 000 plates per m for the 500 bp fragment) and the separation was completed in 4 min for 1000 bp fragment ladder. The cost of a given chip is approximately $0.15 and it takes less than 10 minutes to prepare a single device.
Resumo:
The T2K collaboration reports a precision measurement of muon neutrino disappearance with an off-axis neutrino beam with a peak energy of 0.6 GeV. Near detector measurements are used to constrain the neutrino flux and cross section parameters. The Super-Kamiokande far detector, which is 295 km downstream of the neutrino production target, collected data corresponding to 3.01×1020 protons on target. In the absence of neutrino oscillations, 205±17 (syst.) events are expected to be detected and only 58 muon neutrino event candidates are observed. A fit to the neutrino rate and energy spectrum assuming three neutrino flavors, normal mass hierarchy and θ23≤π/4 yields a best-fit mixing angle sin2(2θ23)=1.000 and mass splitting |Δm232|=2.44×10−3 eV2/c4. If θ23≥π/4 is assumed, the best-fit mixing angle changes to sin2(2θ23)=0.999 and the mass splitting remains unchanged.
Resumo:
The T2K experiment has observed electron neutrino appearance in a muon neutrino beam produced 295 km from the Super-Kamiokande detector with a peak energy of 0.6 GeV. A total of 28 electron neutrino events were detected with an energy distribution consistent with an appearance signal, corresponding to a significance of 7.3σ when compared to 4.92 ± 0.55 expected background events. In the PMNS mixing model, the electron neutrino appearance signal depends on several parameters including three mixing angles θ12, θ23, θ13, a mass difference Δm232 and a CP violating phase δCP. In this neutrino oscillation scenario, assuming |Δm232|=2.4×10−3 eV2, sin2θ23=0.5, δCP=0, and Δm232>0 (Δm232<0), a best-fit value of sin22θ13 = 0.140+0.038−0.032 (0.170+0.045−0.037) is obtained.
Resumo:
124 Briefe zwischen Leo Löwenthal und Max Horkheimer; 1 Brief von Leo Löwenthal an Theodor W. Adorno, 29.12.1954; 2 Briefe zwischen Max Horkheimer und Marjorie Fiske, 1954/1955; 2 Briefe zwischen Leo Löwenthal und Frederick Ungar, Oktober 1954; 2 Briefe zwischen Daniel Lerner und Leo Löwenthal, Oktober 1954; 3 Briefe zwischen Leo Löwenthal und Herbert Blumer, Oktober 1954; 1 Brief von Alice H. Maier an H. P. Edelman, 10.06.1954; 2 Briefe von Leo Löwenthal an The Trustes of Hermann Weil Memorial Foundation (New York), 27.04.1955; 1 Brief von Max Horkheimer an The Trustes of Hermann Weil Memorial Foundation (New York), Juni 1954; 4 Briefe zwischen Leo Löwenthal und Chauncy D. Harris, 1954/1955; 2 Briefe zwischen John I. Kirkpatrick und Leo Löwenthal, 1954; 3 Briefe zwischen Leo Löwenthal und R. Wendell Harrison, Mai 1954; 2 Briefe von Leo Löwenthal an Gustave E. von Grunebaum, 1954; 1 Brief von Leo Löwenthal an Morton Grodzins, 12.05.1954; 2 Briefe von Max Horkheimer an Charles Y. Glock, 1954; 1 Brief von Jeremiah Kaplan an Leo Löwenthal, 15.03.1954; 2 Briefe zwischen Leo Löwenthal und Max Rheinstein, März 1954; 1 Brief von Frederick Pollock an Max Rheinstein, [1954];
Resumo:
Average vesicularity of basalt drilled at three sites on the west flank of the Reykjanes Ridge increases with decreasing age. This change apparently records concomitant decrease in water depth at the ridge crest where the basalt was erupted and suggests substantial upward growth of the crest during the past 35 Myr.
Resumo:
Desaturation of coenzyme-A esters of saturated fatty acids is a common feature of sex pheromone biosynthetic pathways in the Lepidoptera. The enzymes that catalyze this step share several biochemical properties with the ubiquitous acyl-CoA Δ9-desaturases of animals and fungi, suggesting a common ancestral origin. Unlike metabolic acyl-CoA Δ9-desaturases, pheromone desaturases have evolved unusual regio- and stereoselective activities that contribute to the remarkable diversity of chemical structures used as pheromones in this large taxonomic group. In this report, we describe the isolation of a cDNA encoding a pheromone gland desaturase from the cabbage looper moth, Trichoplusia ni, a species in which all unsaturated pheromone products are produced via a Δ11Z-desaturation mechanism. The largest ORF of the ≈1,250-bp cDNA encodes a 349-aa apoprotein (PDesat-Tn Δ11Z) with a predicted molecular mass of 40,240 Da. Its hydrophobicity profile is similar overall to those of rat and yeast Δ9-desaturases, suggesting conserved transmembrane topology. A 182-aa core domain delimited by conserved histidine-rich motifs implicated in iron-binding and catalysis has 72 and 58% similarity (including conservative substitutions) to acyl-CoA Δ9Z-desaturases of rat and yeast, respectively. Northern blot analysis revealed an ≈1,250-nt PDesat-Tn Δ11Z mRNA that is consistent with the spatial and temporal distribution of Δ11-desaturase enzyme activity. Genetic transformation of a desaturase-deficient strain of the yeast Saccharomyces cerevisiae with an expression plasmid encoding PDesat-Tn Δ11Z resulted in complementation of the strain’s fatty acid auxotrophy and the production of Δ11Z-unsaturated fatty acids.
Resumo:
Durum wheat (Triticum turgidum L. var durum) cultivars exhibit lower Zn efficiency than comparable bread wheat (Triticum aestivum L.) cultivars. To understand the physiological mechanism(s) that confers Zn efficiency, this study used 65Zn to investigate ionic Zn2+ root uptake, binding, and translocation to shoots in seedlings of bread and durum wheat cultivars. Time-dependent Zn2+ accumulation during 90 min was greater in roots of the bread wheat cultivar. Zn2+ cell wall binding was not different in the two cultivars. In each cultivar, concentration-dependent Zn2+ influx was characterized by a smooth, saturating curve, suggesting a carrier-mediated uptake system. At very low solution Zn2+ activities, Zn2+ uptake rates were higher in the bread wheat cultivar. As a result, the Michaelis constant for Zn2+ uptake was lower in the bread wheat cultivar (2.3 μm) than in the durum wheat cultivar (3.9 μm). Low temperature decreased the rate of Zn2+ influx, suggesting that metabolism plays a role in Zn2+ uptake. Ca inhibited Zn2+ uptake equally in both cultivars. Translocation of Zn to shoots was greater in the bread wheat cultivar, reflecting the higher root uptake rates. The study suggests that lower root Zn2+ uptake rates may contribute to reduced Zn efficiency in durum wheat varieties under Zn-limiting conditions.
Resumo:
High Cd content in durum wheat (Triticum turgidum L. var durum) grain grown in the United States and Canada presents potential health and economic problems for consumers and growers. In an effort to understand the biological processes that result in excess Cd accumulation, root Cd uptake and xylem translocation to shoots in seedlings of bread wheat (Triticum aestivum L.) and durum wheat cultivars were studied. Whole-plant Cd accumulation was somewhat greater in the bread wheat cultivar, but this was probably because of increased apoplastic Cd binding. Concentration-dependent 109Cd2+-influx kinetics in both cultivars were characterized by smooth, nonsaturating curves that could be dissected into linear and saturable components. The saturable component likely represented carrier-mediated Cd influx across root-cell plasma membranes (Michaelis constant, 20–40 nm; maximum initial velocity, 26–29 nmol g−1 fresh weight h−1), whereas linear Cd uptake represented cell wall binding of 109Cd. Cd translocation to shoots was greater in the bread wheat cultivar than in the durum cultivar because a larger proportion of root-absorbed Cd moved to shoots. Our results indicate that excess Cd accumulation in durum wheat grain is not correlated with seedling-root influx rates or root-to-shoot translocation, but may be related to phloem-mediated Cd transport to the grain.
Resumo:
Chronic administration of estrogen to the Fischer 344 (F344) rat induces growth of large, hemorrhagic pituitary tumors. Ten weeks of diethylstilbestrol (DES) treatment caused female F344 rat pituitaries to grow to an average of 109.2 +/- 6.3 mg (mean +/- SE) versus 11.3 +/- 1.4 mg for untreated rats, and to become highly hemorrhagic. The same DES treatment produced no significant growth (8.9 +/- 0.5 mg for treated females versus 8.7 +/- 1.1 for untreated females) or morphological changes in Brown Norway (BN) rat pituitaries. An F1 hybrid of F344 and BN exhibited significant pituitary growth after 10 weeks of DES treatment with an average mass of 26.3 +/- 0.7 mg compared with 8.6 +/- 0.9 mg for untreated rats. Surprisingly, the F1 hybrid tumors were not hemorrhagic and had hemoglobin content and outward appearance identical to that of BN. Expression of both growth and morphological changes is due to multiple genes. However, while DES-induced pituitary growth exhibited quantitative, additive inheritance, the hemorrhagic phenotype exhibited recessive, epistatic inheritance. Only 5 of the 160 F2 pituitaries exhibited the hemorrhagic phenotype; 36 of the 160 F2 pituitaries were in the F344 range of mass, but 31 of these were not hemorrhagic, indicating that the hemorrhagic phenotype is not merely a consequence of extensive growth. The hemorrhagic F2 pituitaries were all among the most massive, indicating that some of the genes regulate both phenotypes.
Resumo:
Two octavo-sized leaves containing a handwritten copy of the vote of the Harvard Corporation during the June 10, 1799 meeting authorizing Judge John Lowell and Judge Oliver Wendell to be a committee to attend to business with the state legislature related to the pending bill before the General Court regarding the College's real estate tax exemptions. The vote also authorized Professor Pearson to work with the Committee as needed. The document is addressed to Professor Pearson and signed by President Willard.
Resumo:
Lists books borrowed by many individuals, including Governor William Shirley, Colonel Brinley, General Brattle, Secretary Willard, Judge Danforth, Colonel Wendell, Thomas Oliver, Christ Bridge Marsh, and Francis Foxcroft. Entries include the author and title of the borrowed volumes.
Resumo:
This small soft-cover notebook contains a manuscript copy of the valedictory address given at the July 6, 1718 Harvard Commencement by graduate John Eyre. The fly leaf lists six names of individuals who died in 1720. The text includes edits and struck-through words.
Resumo:
Handwritten diploma with the Harvard University seal conferring a bachelor's degree on Cornelius Coolidge and signed by the members of the Harvard Corporation: President Joseph Willard; Fellows Oliver Wendell, John Lowell, James Bowdoin, Simeon Howard, and John Lathrop; and Treasurer Ebenezer Storer.
Resumo:
Black and white composition book sent to the Harvard College Library containing a typed "copy of notes made in the spring of 1886" by John H. Buck. Includes historical information, and physical descriptions and valuations of the Great Salt, the Stoughton Cup, the Browne Cup, and the christening basin acquired with the donation of Oliver Wendell, as well as notes on other gifts of silver.
Resumo:
The volume contains acknowledgements of the disbursements of Harvard Tutor Henry Flynt's estate written in the hands of the respective beneficiaries. The entries begin on February 27, 1760 following Flynt's death on February 13, 1760, and continue through May 9, 1767. Each receipt includes the date, name of the executors, description of the property, beneficiary's name, and signature. The beneficiaries include the wife of Sol. Davy, Dorothy Jackson, Edmund Quincy, J. Henry Quincy, Esther and Stephen Richard (received by attorney Nicholas Boylston), Dorothy Skinner (also received for her by her husband Richard Skinner), John Wendell, Edmund Wendell, Katherine Wendell, and Oliver Wendell, as well as Harvard College (received by Harvard Treasurer Thomas Hubbard), and the Deacons of the First Church of Cambridge. The volume also includes a loose document titled "Account from Messrs Edmund & Josiah Quincy Settled & Ballanced March 31, 1749."