959 research outputs found
A polarized-light spectroscopy study of interactions of a hairpin polyamide with DNA
No full textWe here study the interactions of a polyamide with large DNA, and compare to those of minor groove binder distamycin (DST), including high ligand/DNA binding ratios. Specific as well as nonspecific binding is probed using polarized-light spectroscopy combined with singular value decomposition analysis. Circular and linear dichroism data confirm binding geometries consistent with minor groove binding for both of the ligands. Interestingly, at high and intermediate ligand/DNA ratios the polyamide exhibits no significant sequence discrimination between mixed-sequence (calf thymus) and AT DNA as compared to DST. Each ligand is concluded to exhibit two different binding modes depending upon ligand/DNA ratio and nucleo-base sequence. At high binding ratios, distinct differences between the ligands are observed: circular dichroism spectra exciton effects provide evidence of bimolecular interactions of the polyamide when bound to AT-DNA, whereas no effects are seen with DST or mixed-sequence DNA. Also linear dichroism indicates that a change in binding geometry occurs at high polyamide/AT ratios, and that the effect occurs only with polyamide in contrast to DST. Since the effect is insignificant with DST, or with calf thymus DNA, it is concluded that it relates to the sizes of the ligands and the minor grooves, becoming critical in the limit of crowding
ULF vlny/fluktuace ve forešoku: Statistický přístup
No full textTitle: ULF waves/fluctuations in the foreshock: Statistical approach Author: Anna Mita Department: Department of Surface and Plasma Science Supervisor: Prof. RNDr. Jana Šafránková, DrSc., Department of Surface and Plasma Science Abstract: The thesis deals with ultra-low frequency (ULF) wave activity in the terrestrial foreshock, a turbulent region upstream of the bow shock that plays a crucial role in the interaction of the solar wind with the magnetosphere. In the thesis, we analyze some aspects of the behavior of ULF waves/fluctuations of the magnetic field, using a statistical point of view. We focused (i) on the boundary between the pure solar wind and wave activity region represented by enhanced ULF fluctuations, and on the changes of the boundary position with solar wind conditions and interplanetary magnetic field orientation; and (ii) on growth rates of foreshock ULF fluctuations at different distances from the bow shock with a special highlight on a region close to the Moon. In both statistical studies, we use THEMIS/ARTEMIS data and describe the behavior of fluctuations by the standard deviations in the ULF range of 0.0017-0.17 Hz. We present a novel coordinate system, determine so-called "foreshock ULF boundary" and report its realistic shape that is consistent with the theory of the foreshock...Název práce: ULF vlny/fluktuace ve forešoku: Statistický přístup Autor: Anna Mita Katedra: Katedra fyziky povrchů a plazmatu Vedoucí disertační práce: Prof. RNDr. Jana Šafránková, DrSc., Katedra fyziky povrchů a plazmatu Abstrakt: Předložená práce se zabývá ULF (Ultra Low Frequency) fluktuacemi v turbulentní oblasti před rázovou vlnou (forešok), která hraje klíčovou roli v interakci slunečního větru s magnetosférou Země. V práci analyzujeme některé aspekty chování ULF vln/fluktuací magnetického pole s využitím statistického zpracování dat naměřených dvěma družicemi projektu THEMIS/ARTEMIS. Zaměřili jsme se (i) na hranici mezi neporušeným slunečním větrem a oblastí charakterizovanou vysokými ULF fluktuacemi a na změny polohy této hranice v závislosti na podmínkách ve slunečním větru a na orientaci meziplanetárního magnetického pole; a (ii) na rychlost růstu nebo tlumení ULF vln/fluktuací v různých vzdálenostech od rázové vlny se zvláštním zřetelem na oblast blízko Měsíce. Ve statistických studiích popisujeme chování fluktuací pomocí směrodatných odchylek v rozsahu 0,0017-0,17 Hz. V práci představujeme nový souřadnicový systém umožňující určit tzv. "foreshock ULF boundary", diskutujeme nalezený tvar a ukazujeme, že je v souladu s teorií formování forešoku. Ve druhé studii se soustřeďujeme na růst (případně...Katedra fyziky povrchů a plazmatuDepartment of Surface and Plasma ScienceFaculty of Mathematics and PhysicsMatematicko-fyzikální fakult
ULF waves/fluctuations in the foreshock: Statistical approach
No full textTitle: ULF waves/fluctuations in the foreshock: Statistical approach Author: Anna Mita Department: Department of Surface and Plasma Science Supervisor: Prof. RNDr. Jana Šafránková, DrSc., Department of Surface and Plasma Science Abstract: The thesis deals with ultra-low frequency (ULF) wave activity in the terrestrial foreshock, a turbulent region upstream of the bow shock that plays a crucial role in the interaction of the solar wind with the magnetosphere. In the thesis, we analyze some aspects of the behavior of ULF waves/fluctuations of the magnetic field, using a statistical point of view. We focused (i) on the boundary between the pure solar wind and wave activity region represented by enhanced ULF fluctuations, and on the changes of the boundary position with solar wind conditions and interplanetary magnetic field orientation; and (ii) on growth rates of foreshock ULF fluctuations at different distances from the bow shock with a special highlight on a region close to the Moon. In both statistical studies, we use THEMIS/ARTEMIS data and describe the behavior of fluctuations by the standard deviations in the ULF range of 0.0017-0.17 Hz. We present a novel coordinate system, determine so-called "foreshock ULF boundary" and report its realistic shape that is consistent with the theory of the foreshock..
Dream on, but with your eyes open: An obituary for Ulf Kadritzke (1943-2020)
No full textUlf Kadritzke war der PROKLA als Autor und Mitglied des Redaktionsbeirats viele Jahre eng verbunden. Mit seinen Ideen und seinem Engagement hat er nicht nur die PROKLA bereichert und geprägt. Am 14. November 2020 verstarb Ulf Kadritzke überraschend.Ulf Kadritzke was closely associated with PROKLA for many years as an author and a member of the editorial advisory board. With his ideas and commitment, he enriched and shaped not only PROKLA. Ulf Kadritzke passed away unexpectedly on November 14, 2020
Ulf eta Cornelia: Berlingo maitasun istorio bat
No full text“Ulf and Cornelia: A Berlin love story” is part of the PhD thesis Berlin fin de millenium: An Experiment in Corporeal Ethnography, carried out between 1998 and 2003. In this article, the author puts into practice his investigative endeavor as a discovery process, narrating his encounters with Ulf and Cornelia, two bodies in transit in a Berlin characterized by its dramatic urban transformation. The focus of the ethnography is Ulf’s enamored experience. Using wonder as a knowledge technique, we will dive in the realm previous to the formation of stable identities, meaning the domain of corporeal stimulus and unconscious impulses. The subjects that appear in the scenes of this article, the author himself and the city where they live are in construction.“Ulf y Cornelia: una historia de amor berlinesa” es un apartado que pertenece a la tesis Berlín fin de milenio: un experimento en la etnografía corporal, realizada entre 1998 y 2003. En este artículo, el autor lleva a cabo una labor de investigación puesta en práctica como un proceso de descubrimientos, relatando sus encuentros con Ulf y Cornelia, dos cuerpos en tránsito en un Berlín sumido en una dramática transformación urbana. La etnografía está enfocada particularmente en la experiencia de enamoramiento de Ulf. Utilizando la capacidad de asombro como técnica para el conocimiento, nos sumergiremos en el ámbito anterior a la formación de identidades estables, es decir, en el dominio de estímulos corporales e impulsos inconscientes. Se trata, pues, de un artículo donde tanto los sujetos en escena como el propio autor y la ciudad en la que viven están en proceso de construcción.“Ulf eta Cornelia: maitasun istorio bat Berlinen”, 1999-2003 urteen artean garatutako Berlin fin de millenium: gorputz etnografíaren gaineko esperimentu bat tesiaren ataletako bat da. Artikulu honetan, autoreak, Ulfekin eta Corneliarekin, Berlin behin behineko bizilekutzat duten bi gorputzekin, bizitako uneak kontatzen dizkigu. Zehazki, Ulfen maitemintzea izango da etengabeko aurkikuntza prozesuan oinarritutako etnografía honen ardatza. Lilurarako gaitasuna ezagutzarako teknika bezala erabiliaz, nortasun egonkorrak eratu aurretiko eremura eramango gaitu, hau da, gorputz-estimulu eta bulkada inkontzienteen mundura. Azpimarratu behar da, artikulu honetan protagonista diren pertsonak, autorea bera eta bizi diren hiria eraikuntza prozesuan daudela
Simulation of Bounce Resonance ULF Wave-Particle Interactions
No full textPoloidal mode ultra-low-frequency (ULF) waves with high azimuthal mode number (high-m) are common throughout Earth's magnetosphere. The electric fields in these waves are on the order of tens of millivolts per meter, and are large enough to energize ions and electrons via drift- and drift-bounce wave-particle resonance. In this article, we present full orbit test-particle simulations of drift-bounce resonance using a numerical model of ULF waves. The model uses a dipole magnetic field and can accommodate a realistic ionosphere with height-resolved Pedersen and Hall conductivity. It is demonstrated that second-harmonic poloidal mode waves can energize ions to tens of keV depending on the wave amplitude. The test-particle simulations also predict ion flux oscillations that have energy dispersion similar to many satellite observations. It will be shown that features in the energy dispersion are in agreement with theoretical considerations.CPCI-S(ISTP)[email protected]; [email protected]
Energi, Mat, Träning – nutrition i ett helhetsperspektiv
No full textVad och när skall jag äta för att göra min träning effektivast? Varför är det så svårt att gå ner i vikt? Vad händer när man lagar mat? Vad är egentligen energi? Kommer maten att räcka till alla på jorden? Dessa och en rad andra frågor vill denna bok ge dig den vetenskapliga bakgrunden till att själv kunna börja besvara. Inga förkunskaper krävs utan begreppen förklaras allt eftersom. Boken är lämplig som introduktion till näringslära samt som kursbok i grundläggande kurser i nutrition och idrottsnutrition. Den vänder sig även allmänt till dig som är intresserad av mat och hälsa. © StudentlitteraturFormler: Ulf Ellervik</p
Synthetic analogs of sialyl Lewis x
No full textThe sialyl Lewis x (SLex) tetrasaccharide is the smallest recognizable ligand for selectins. The selectins constitute a vital part of the inflammatory cascade for recruitment of leukocytes to a site of tissue damage or microbial infection. If too many leukocytes are recruited, normal, not injured, cells can be damaged; a process known from chronic inflammatory diseases such as reumatoid arthritis, psoriasis, and from septic shock and reperfusion damage. Sialyl Lewis x saccharides were originally identified as human tumor-associated antigens and are found on all highly malignant types of cancer cells. The identification of the SLex tetrasaccharide and later synthetic efforts have elucidated the biologically important features of the molecule. A large number of analogs and mimics have been designed in order to get simpler and more stable compounds for use as anti-inflammatory drugs. Sialic acid-containing oligosaccharides, such as sialyl Lewis x, can form lactones under slightly acidic conditions. These lactones are generally more immunogenic due to their increased rigidity and it has been proposed that the lactones are the actual immunogens. The lactones are however not hydrolytically stable and are therefore difficult to investigate and to raise antibodies against. Lactams were introduced as analogs to lactones and were found to be structurally similar and more stable against hydrolysis. Lactam analogs of a number of monosialylated gangliosides (GM2, GM3, GM4) were synthesized and used with success. This thesis describes the synthesis of the sialyl Lewis x tetrasaccharide, the Lewis x trisaccharide, the 1’’’-2’-, 1’’’-4’-lactam- and 2-acetamido analogs of the sialyl Lewis x tetrasaccharide, the 2- and 4-acetamido- and 2- and 4-lactam analogs of the Lewis x trisaccharide. The key-steps in the syntheses were regio- and stereoselective galactosylations of one common monosaccharide diol acceptor, stereoselective fucosylation and regio- and stereoselective sialylations to yield the oligosaccharidic products in 10-62% over-all yield from monosaccharidic starting materials
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