Ueber die Eigenschaften und den Desinfectionswerth des Abietineentheeres und des Acetum pyrolignosum

Ohne Zusammenfassung     

Magnetic Relaxometry with an Atomic Magnetometer and SQUID Sensors on Targeted Cancer Cells

Magnetic relaxometry methods have been shown to be very sensitive in detecting cancer cells and other targeted diseases. Superconducting Quantum Interference Device (SQUID) sensors are one of the primary sensor systems used in this methodology because of their high sensitivity with demonstrated capabilities of detecting fewer than 100,000 magnetically-labeled cancer cells. The emerging technology of atomic magnetometers (AM) represents a new detection method for magnetic relaxometry with high sensitivity and without the requirement for cryogens. We report here on a study of magnetic relaxometry using both AM and SQUID sensors to detect cancer cells that are coated with superparamagnetic nanoparticles through antibody targeting. The AM studies conform closely to SQUID sensor results in the measurement of the magnetic decay characteristics following a magnetization pulse. The AM and SQUID sensor data are well described theoretically for superparamagnetic particles bound to cells and the results can be used to determine the number of cells in a cell culture or tumor. The observed fields and magnetic moments of cancer cells are linear with the number of cells over a very large range. The AM sensor demonstrates very high sensitivity for detecting magnetically labeled cells does not require cryogenic cooling and is relatively inexpensive.     

The kinetic of the oxidation of InSn48

The oxidation of InSn48 has been investigated at partial pressures between 10^-8 Pa and 10⁺⁴ Pa over a temperature range from 22^°C to 250^°C with different analytical methods. The oxide film contains a mixture of several oxides, although indium oxide forms preferentially. Below the melting point a logarithmic growth, and above this, a parabolic growth of the oxide film has been observed. The oxide film formed in air at 250^°C does not become thicker than 50 nm in the first 5 min of oxidation.     

Shape resonances in slow electron scattering by aromatic molecules. I. Anthraquinone derivatives

A series of anthraquinone (C(14)O(2)H(8)) derivatives has been studied by means of electron capture negative ion mass spectrometry (ECNI-MS), photoelectron spectroscopy (PES), and AM1 quantum chemical calculations. Mean lifetimes of molecular negative ions M(-.) (MNI) have been measured. The mechanism of long-lived MNI formation in the epithermal energy region of incident electrons has been investigated. A simple model of a molecule (a spherical potential well with the repulsive centrifugal term) has been applied for the analysis of the energy dependence of cross sections at the first stage of the electron capture process. It has been shown that a temporary resonance of MNI at the energy approximately 0.5 eV corresponds to a shape resonance with lifetime 1-2.10(-13) s in the f-partial wave (l = 3) of the incident electron. The next resonant state of MNI at the energy approximately 1.7 eV has been associated with the electron excited Feshbach resonance (whose parent state is a triplet npi* transition). In all cases the initial electron state of the MNI relaxes into the ground state by means of a radiationless transition, and the final state of the MNI is a nuclear excited resonance with a lifetime measurable on the mass spectrometry timescale. Copyright 1999 John Wiley & Sons, Ltd.     

LEED-AES-Untersuchungen der Oxydation von austenitischen Cr-Ni-Stählen an der (100)-Ebene

Oxidation of austenitic stainless steel has been studied on the (100)-face. Temperature region examinated reaches from room temperature to 1000°C. Oxidation begins with formation of chromium oxide (Cr₂O₃). After this iron oxide (Fe₃O₄) covering the chromium oxide arises gradually. At 500°C Fe₃O₄ is destroyed, and a layer of chromium oxide increases. At 700°C the LEED-pattern was observed to represante Cr₂O₃(111), and at 750°C you can prove FeO(111) on that. At 1000°C the oxide layer is destroyed. All the oxides grow in form of islands.     

Characterization of the adsorption of <Emphasis Type="Italic">ω</Emphasis>-(thiophene-3-yl alkyl) phosphonic acid on metal oxides with AR-XPS

The aim of the work discussed in this paper was to characterize adsorbed self-assembled monolayers on different metal oxide substrates with angle-resolved XPS measurements. The substrates used were silicon wafers (100) coated with 300 nm Al, Ta, or Ti. They were coated with acids by immersing them in an ethanol solution. The orientation of long-chain organic acids adsorbed on metal oxides has been successfully identified by angle-resolved XPS. On Al, Ta, and Ti substrates, C₁₁ chains are orientated in the right manner, i.e. with the phosphonic group at the bottom and the thiophene group on top. The orientations of the C₂ and C₆ chains are not clear. The thickness of the layers could be obtained by using Tougaard nanostructure analysis, and it shows monolayers. A model of the chemical bonds between the phosphonic group and the metal could be developed from the chemical shift. For titanium, all three P–O bonds bind to the metal substrate, whereas only the P–O(H) bond binds to the metal on aluminium and tantalum.     

Magnetic Properties of Nanoparticles Useful for SQUID Relaxometry in Biomedical Applications

We use dynamic susceptometry measurements to extract semiempirical temperature-dependent, 255-400 K, magnetic parameters that determine the behavior of single-core nanoparticles useful for SQUID relaxometry in biomedical applications. Volume susceptibility measurements were made in 5 K degree steps at nine frequencies in the 0.1-1000 Hz range, with a 0.2 mT amplitude probe field. The saturation magnetization (M_s) and anisotropy energy density (K) derived from the fitting of theoretical susceptibility to the measurements both increase with decreasing temperature; good agreement between the parameter values derived separately from the real and imaginary components is obtained. Characterization of the Néel relaxation time indicates that the conventional prefactor, 0.1 ns, is an upper limit, strongly correlated with the anisotropy energy density. This prefactor decreases substantially for lower temperatures as K increases. We find, using the values of the parameters determined from the real part of the susceptibility measurements at 300 K, that SQUID relaxometry measurements of relaxation and excitation curves on the same sample are well described.     

Characterization of magnetite nanoparticles for SQUID-relaxometry and magnetic needle biopsy

Magnetite nanoparticles (Chemicell SiMAG-TCL) were characterized by SQUID-relaxometry, susceptometry, and TEM. The magnetization detected by SQUID-relaxometry was 0.33% of that detected by susceptometry, indicating that the sensitivity of SQUID-relaxometry could be significantly increased through improved control of nanoparticle size. The relaxometry data were analyzed by the moment superposition model (MSM) to determine the distribution of nanoparticle moments. Analysis of the binding of CD34-conjugated nanoparticles to U937 leukemia cells revealed 60,000 nanoparticles per cell, which were collected from whole blood using a prototype magnetic biopsy needle, with a capture efficiency of >65% from a 750 μl sample volume in 1 min.     

The Route to Functional Graphene Oxide

We report on an easy‐to‐use, successful, and reproducible route to synthesize functionalized graphite oxide (GO) and its conversion to graphene‐like materials through chemical or thermal reduction of GO. Graphite oxide containing hydroxyl, epoxy, carbonyl, and carboxyl groups loses mainly hydroxyl and epoxy groups during reduction, whereas carboxyl species remain untouched. The interaction of functionalized graphene with fluorescent methylene blue (MB) is investigated and compared to graphite, fully oxidized GO, as well as thermally and chemically reduced GO. Optical absorption and emission spectra of the composites indicate a clear preference for MB interaction with the GO derivatives containing a large number of functional groups (GO and chemically reduced GO), whereas graphite and thermally reduced GO only incorporate a few MB molecules. These findings are consistent with thermogravimetric, X‐ray photoelectron spectroscopic, and Raman data recorded at every stage of preparation. The optical data also indicate concentration‐dependent aggregation of MB on the GO surface leading to stable MB dimers and trimers. The MB dimers are responsible for fluorescence quenching, which can be controlled by varying the pH value.