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81.
Friedemann K Turshatov A Landfester K Crespy D 《Langmuir : the ACS journal of surfaces and colloids》2011,27(11):7132-7139
A model system for multicompartment nanofibers was fabricated by colloid electrospinning. The obtained nanostructured material consisted of fluorescent polymer nanoparticles that were synthesized in a miniemulsion and then embedded in fluorescently labeled polymer nanofibers. Because of the absence of contrast between both polymers, the immobilized nanoparticles cannot be reliably identified in the nanofibers via electron microscopy or other techniques. Here, we describe investigations on the hybrid material with two-color STED microscopy to localize the nanoparticles and to quantify their distribution along nanofibers with particle and fiber radii down to 50 nm. 相似文献
82.
Sandstede JJ Pabst T Wacker C Wiesmann F Hoffmann V Beer M Kenn W Bauer W Hahn D 《Magnetic resonance imaging》2001,19(2):201-205
Demonstration of the initial results of breath-hold 3D MR coronary angiography with patients using a new intravascular contrast agent (feruglose). Contrast-enhanced 3D MR-coronary angiography was performed in 5 patients with coronary artery disease after administration of feruglose in three different doses (0.5 (n = 3), 2, 5 mg Fe/kg body weight for each patient). MR coronary angiography was performed with an ECG-triggered 3D-FLASH-sequence during breath-hold at 1.5 T (TR 6.8 ms, TE 2.5 ms, flip-angle 30 degrees ). To reduce data acquisition time, only the two anterior elements of the phased-array body coil were activated. The data acquisition window within the cardiac cycle ranged between 217-326 ms depending on the matrix. Signal-to-noise (SNR) and contrast-to-noise ratios (CNR) of the coronary arteries were analyzed, and the results for the detection of coronary artery stenoses were compared with those obtained by conventional coronary angiography. SNR and CNR revealed an improved image quality at a dose of 2 mg Fe/kg compared with the lower dose, but no further improvement was obtained by rising the dose to 5 mg Fe/kg. Except for the left circumflex artery of one patient, at minimum the proximal parts of all four main coronary arteries could be imaged for all patients. Within the visible parts of the coronary arteries, six of eight significant coronary stenoses were identified correctly. Imaging of the proximal parts of the coronary arteries including detection of stenoses is possible during breath-hold using an intravascular contrast agent. 相似文献
83.
Falk Pabst Jen-Hui Chang Kati Finzel Miroslav Kohout Peer Schmidt Michael Ruck 《无机化学与普通化学杂志》2020,646(3):149-155
Black and irregularly shaped crystals of the bismuth-rich bromide Bi5Br4 were obtained as a by-product of the reaction of CsBr, Bi, and BiBr3. X-ray diffraction on a single-crystal revealed its orthorhombic structure with the space group Pmmn (no. 59) and lattice parameters a = 1800.0(2) pm, b = 1476.1(1) pm, and c = 924.5(2) pm at 296 K. The structure is composed of Bi82+ and Bi95+ polycations and bromidobismuthate(III) anions according to the structured formula Bi5Br4 = Bi20Br16 = Bi82+Bi95+[BiBr5]2–[Bi2Br11]5–. Bi5Br4 is the bismuth-richest among the bismuth subhalides containing isolated polycations. Extensive differential scanning calorimetry studies indicate that Bi5Br4 decomposes at 262 °C, i.e. one degree below the bismuth-rich eutectic at 263 °C. All attempts towards a rational synthesis yielded predominantly the neighboring phases BiBr and Bi6Br7. 相似文献
84.
85.
Jürgen Simon Werner Schulze Lutz -Werner Friedemann 《Analytical and bioanalytical chemistry》1974,268(3):185-189
The co-precipitation of Mn2+ ions with gelatinous Al(OH)3 was investigated as a function of pH and concentration of Mn2+ in the supernatant solution. For each pH of an acceptable constant value isothermes of co-precipitation were found, obeying formally Langmuir's equation. The maximum quantity of Mn2+, being sorbable, increases in accordance with pH. The functional relationship between Langmuir's constants and the concentration of OH? in the suspension can be expressed by two linear equations. These facts permit co-precipitation of Mn2+ ions to be considered as a counterion-exchange, the reason of which being a specific adsorption of OH? ions. The equations mentioned above allow the Mn2+ sorption to be described quantitatively in presence of a definitive amount of K+ being a competing cation. 相似文献
86.
Phonon dispersion curves in wurtzite-structure GaN determined by inelastic x-ray scattering 总被引:1,自引:0,他引:1
Ruf T Serrano J Cardona M Pavone P Pabst M Krisch M D'Astuto M Suski T Grzegory I Leszczynski M 《Physical review letters》2001,86(5):906-909
We have investigated the lattice dynamics of a wurtzite GaN single crystal by inelastic x-ray scattering. Several dispersion branches and phonons at high-symmetry points have been measured, including the two zone-center Raman- and infrared-inactive silent modes. The experiments have been complemented by ab initio calculations. They are in very good agreement with our measurements, not only for phonon energies, but also for scattering intensities, thus validating the correctness of the eigenvectors. Other phenomenological and ab initio theories exhibit significant differences. 相似文献
87.
88.
89.
Lukas Naumann Patrick Schlossbauer Florian Klingler Friedemann Hesse Kerstin Otte Christian Neusüß 《Journal of separation science》2022,45(12):2034-2044
The analysis of monoclonal antibodies glycosylation is a crucial quality control attribute of biopharmaceutical drugs. High throughput screening approaches for antibody glycoform analysis are required in various stages of process optimization. Here, we present high throughput screening suitable mass spectrometry-based workflows for the analysis of intact antibody glycosylation out of cell supernatants. Capillary electrophoresis and liquid chromatography were coupled with quadrupole time-of-flight mass spectrometry or Orbitrap mass spectrometry. Both separation methods offer fast separation (10–15 min) and the capability to prevent the separated cell supernatant matrix to enter the mass spectrometry by post-separation valving. Both mass spectrometry instruments provide comparable results and both are sufficient to determine the glycosylation pattern of the five major glycoforms of the measured antibodies. However, the Orbitrap yields higher sensitivity of 25 μg/mL (CE-nanoCEasy-Orbitrap mass spectrometry) and 5 μg/mL (liquid chromatography-Orbitrap mass spectrometry). Data processing was optimized for a faster processing and easier detection of low abundant glycoforms based on averaged charge-deconvoluted mass spectra. This approach combines a non-target glycoform analysis while yielding the same glycosylation pattern as the traditional approach based on extracted ion traces. The presented methods enable the high throughput screening of the glycosylation pattern of antibodies down to low μg/mL-range out of cell supernatant without any sample preparation. 相似文献
90.
Bastian Bernhardt Friedemann Dressler Dr. André K. Eckhardt Dr. Jonathan Becker Prof. Dr. Peter R. Schreiner 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(22):6732-6739
As sulfur-containing organic molecules thioamides and their isomers are conceivable intermediates in prebiotic chemistry, for example, in the formation of amino acids and thiazoles and resemble viable candidates for detection in interstellar media. Here, we report the characterization of parent thioformamide in the solid state via single-crystal X-ray diffraction and its photochemical interconversion to its hitherto unreported higher energy tautomer thiolimine in inert argon and dinitrogen matrices. Upon photogeneration, four conformers of thiolimine form, whose ratio depends on the employed wavelength. One of these conformers interconverts due to quantum mechanical tunneling with a half-life of 30–45 min in both matrix materials at 3 and 20 K. A spontaneous reverse reaction from thiolimine to thioformamide is not observed. To support our experimental findings, we explored the potential energy surface of the system at the AE-CCSD(T)/aug-cc-pCVTZ level of theory and computed tunneling half-lives with the CVT/SCT approach applying DFT methods. 相似文献