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51.
Let Ω be an exterior domain in
It is shown that Ornstein-Uhlenbeck operators L generate C0-semigroups on Lp(Ω) for p ∈ (1, ∞) provided ∂Ω is smooth. The method presented also allows to determine the domain D(L) of L and to prove Lp − Lq smoothing properties of etL. If ∂Ω is only Lipschitz, results of this type are shown to be true for p close to 2.
Received: 16 December 2004; revised: 4 February 2005 相似文献
52.
H. G. Börner H. R. Koch H. Seyfarth T. von Egidy W. Mampe J. A. Pinston K. Schreckenbach D. Heck 《Zeitschrift für Physik A Hadrons and Nuclei》1978,286(1):31-43
For the investigation of vibrational states in odd A nuclei we have studied the level structure of239U by the238U (n thermal,γ) reaction. Various complementary measurement techniques as curved-crystal-, anti-Compton-,γ-γ coincidence- and conversion electron spectroscopy have been applied. The resulting data have been used to establish the deexcitation scheme of239U up to ~1.3 MeV and to make spin assignments. Most of the levels are interpreted in terms of the Nilsson model. The data also indicate the presence of the Nilsson states ¦501?¦ and ¦750¦. Three members of theΒ-vibrational band built on the ¦631?¦ state and one member of theΒ-vibration built on the ¦622↑¦ ground state have been identified through transitions with strongE0 admixtures. The octupole vibrational state built on the ¦631?¦ band is proposed at 815 keV. 相似文献
53.
C.-D. Zhao G. Haase M. Heck M. Tufail P. Vater H. A. Khan 《Isotopes in environmental and health studies》2013,49(6):296-299
222Rn dissolved in drilling fluids of the KTB (Kontinentales Tiefbohrprogramm der Bundesrepublik Deutschland) pilot hole has been determined using solid state nuclear track detector (SSNTD) technique:The α-sensitive SSNTD CR-39 was used to measure the a-activity of 222Rn. Well-defined conditions for Rn-measurements could be established by employing a mica nuclear track microfilter to separate the detector containing air volume from the volume containing the water. This technique has been applied to determine quantitatively the 222 Rn-concentration as a function of depth of the borehole down to 4000 m. 相似文献
54.
Erwin A. J. M. Bente Yohan Barbarin Martijn J. R. Heck Meint K. Smit 《Optical and Quantum Electronics》2008,40(2-4):131-148
In this paper a model and simulation results of integrated semiconductor passively modelocked ring lasers are presented. The model includes nonlinear effects such as two-photon absorption and a non-linear refractive index, a logarithmic gain-carrier relation, and concentration dependent radiative and non-radiative carrier recombination rates. The optical bandwidth of the system is controlled by a digital filter. The model has been used to simulate two geometries of ring modelocked lasers. The first is a symmetric design, where the two counter propagating pulses in the cavity experience the same amplification and absorption. The second is an asymmetric design where the differences for the two directions of pulse propagation are maximised. Simulation results show that a symmetrical cavity shows a several times wider window for its operating parameters for stable modelocking. 相似文献
55.
Dr. Robert Lizatović Marvin Assent Arjan Barendregt Jonathan Dahlin Dr. Anna Bille Katharina Satzinger Dagnija Tupina Prof. Albert J. R. Heck Dr. Stefan Wennmalm Dr. Ingemar André 《Angewandte Chemie (International ed. in English)》2018,57(35):11334-11338
Protein‐based encapsulation systems have a wide spectrum of applications in targeted delivery of cargo molecules and for chemical transformations in confined spaces. By engineering affinity between cargo and container proteins it has been possible to enable the efficient and specific encapsulation of target molecules. Missing in current approaches is the ability to turn off the interaction after encapsulation to enable the cargo to freely diffuse in the lumen of the container. Separation between cargo and container is desirable in drug delivery applications and in the use of capsids as catalytic nanoparticles. We describe an encapsulation system based on the hepatitis B virus capsid in which an engineered high‐affinity interaction between cargo and capsid proteins can be modulated by Ca2+. Cargo proteins are loaded into capsids in the presence of Ca2+, while ligand removal triggers unbinding inside the container. We observe that confinement leads to hindered rotation of cargo inside the capsid. Application of the designed container for catalysis was also demonstrated by encapsulation of an enzyme with β‐glucosidase activity. 相似文献
56.
57.
Capillary polystyrene-divinylbenzene (PS-DVB) monolithic columns were used to separate differentially acetylated intact IM9 protein isoforms. Compared to the unmodified form, the hydrophobic shift for intact acetylated isoforms was significant under standard reversed-phase conditions (32.5-45% acetonitrile in 10 min). The high chromatographic resolution of the PS-DVB monolithic columns resulted in peak widths at half height of 4-5s. This allowed us to nearly completely resolve a number of peaks greater than the number of possible acetylation sites. This observation suggested that not only the number, but also the location of the acetylations on the protein had a significant effect on the retention. Matrix-assisted laser desorption ionization time-of-flight MS and MS/MS were used to confirm the chromatographic separation of isoforms. It was found that the acetylations site, especially on the N-terminus, has an effect on the retention on the PS-DVB column. 相似文献
58.
Competition between lipases and monoglycerides at interfaces 总被引:3,自引:0,他引:3
Reis P Holmberg K Miller R Krägel J Grigoriev DO Leser ME Watzke HJ 《Langmuir : the ACS journal of surfaces and colloids》2008,24(14):7400-7407
Tensiometry (the pendant drop technique), interfacial shear rheology, and ellipsometry have been used to study the effect of polar lipids that are generated during fat digestion on the behavior of lipases at the oil-water interface. Both Sn-1,3 regiospecific and nonregiospecific lipases have been used, and a noncatalytically active protein, beta-lacloglobulin, has been used as reference in the interfacial shear rheology experiments. The results from the pendant drop measurements and the interfacial rheology studies were in agreement with each other and demonstrated that the Sn-2 monoglyceride, which is one of the lipolysis products generated when a Sn-1,3 regiospecific lipase catalyzes triglyceride hydrolysis, is very interfacially active and efficiently expels the enzyme from the interface. Ellipsometry conducted at the liquid-liquid interface showed that the lipase forms a sublayer in the aqueous phase, just beneath the monoglyceride-covered interface. Sn-1/3 monoglycerides do not behave this way because they are rapidly degraded to fatty acid and glycerol and the fatty acid (or the fatty acid salt) does not have enough interfacial activity to expel the lipase from the interface. Since the lipases present in the gastrointestinal tract are highly Sn-1,3 regiospecific, we believe that the results obtained can be transferred to the in vivo situation. The formation of stable and amphiphilic Sn-2 monoglycerides can be seen as a self-regulatory process for fat digestion. 相似文献
59.
Krejci Pavel; Rocca Elisabetta; Sprekels Jurgen 《Journal London Mathematical Society》2007,76(1):197-210
We propose a model for non-isothermal phase transitions withnon-con-served order parameter driven by a spatially non-localfree energy with respect to both the temperature and the orderparameter. The resulting system of equations is shown to bethermodynamically consistent and to admit a strong solution. 相似文献
60.
CM Silva MF Duarte ML Mira MH Florêncio K Versluis AJ Heck 《Rapid communications in mass spectrometry : RCM》1999,13(12):1098-1103
Fast atom bombardment, combined with high-energy collision-induced tandem mass spectrometry, has been used to investigate gas-phase metal-ion interactions with captopril, enalaprilat and lisinopril, all angiotensin-converting enzyme inhibitors.Suggestions for the location of metal-binding sites are presented. For captopril, metal binding occurs most likely at both the sulphur and the nitrogen atom. For enalaprilat and lisinopril, binding preferably occurs at the amine nitrogen. Copyright 1999 John Wiley & Sons, Ltd. 相似文献