Separation of phenylthiohydantoin amino acids by capillary electrochromatography

Capillary electrochromatography (CEC) was employed as a rapid and high-efficiency method for the isocratic separation of all 20 important phenylthiohydantoin (PTH) amino acids, the end products of Edman degradation during N-terminal protein sequencing. For this purpose, 75 microm ID fused-silica capillaries were packed with standard 3 microm Hypersil octadecyl silica (ODS) particles using a two-step column fabrication process, which represents a fast, reliable and efficient means of producing long-term stable columns. The influence of solvent composition, pH, type of buffer cation, buffer concentration, and temperature on retention behavior of PTH amino acids was investigated. Same-day and day-to-day reproducibility of the retention times (over a period of two months) were found to be better than 3%. When comparing this new technique with traditional reversed phase-high performance liquid chromatography (RP-HPLC) methods applied in automated protein sequenators, CEC shows essentially shorter separation times and superior resolution.     

Genetic variability of pepper (Capsicum annuum L.) seed proteins studied by 2-D electrophoresis with immobilized pH gradients.

Ten pepper (Capsicum annuum L.) inbred lines were successfully differentiated by two-dimensional electrophoresis with immobilized pH gradients. Qualitative polymorphism of water-soluble and urea/detergent-soluble seed proteins, respectively, was investigated by computer analysis and used for establishing a dendrogram derived from maximum-parsimony analysis. The dendrogram calculated from urea/detergent-soluble proteins shows four types of distance indices, whereas water-soluble proteins show two sets of inbred lines with similar intraset distance indices. The validity of the dendrograms with respect to quantitative inherited traits, such as cold tolerance and earliness, will be tested by field trials.     

Collision-induced light scattering from fluids composed of tetrahedral molecules. I

The collision-induced polarized and depolarized light scattered from fluids composed of tetrahedral molecules is examined. The correlation functions for the first-order term of the collision-induced rotational Raman effect proposed by Buckingham and Tabisz [21] are derived in the limit of binary interactions. They involve rotational correlation functions of the dipole-quadrupole polarizability, which for tetrahedral molecules is an irreducible third-rank tensor, and third-rank tensor correlation functions for relative translational motion. From a comparison of the frequency-dependent depolarization ratio of liquid carbon tetrachloride with the theoretical prediction it is concluded that also in liquids the collision-induced rotational Raman effect may contribute significantly to the depolarized spectrum for large frequency shifts.     

Optical sensors

Summary A fibre optic biosensor for ethanol was developed, which is based on the enzymatic oxidation of ethanol. The sensor layer contains an oxygen-sensitive fluorescing indicator which reports the decrease in the local oxygen partial pressure as the result of the enzymatic oxidation. The sensor measures in the 50–500 mmol/l ethanol range, with an accuracy of ± 4 mmol/l at 100 mmol/l. The detection limit is 10 mmol/l ethanol.

---

Optische SensorenTeil 20. Ein faseroptischer Biosensor für Ethanol

---

Presented in part at the Biosensor International Workshop 1987 at GBF, Braunschweig, June 1987     

Thermal heat reservoirs via Gauss' principle of least constraint; Dissipation,chaos, and phase-space dimensionality loss in one-dimensional chains

We use Gauss' principle of least constraint to impose different kinetic temperatures on the two halves of a periodic one-dimensional chain. The thermodynamic result is heat flow, as predicted by the Second Law of Thermodynamics. The statistical-mechanical result can be either a phase-space limit cycle or a strange attractor, depending on the chain length and the size of the temperature difference. We document the sensitivity of the Lyapunov spectrum and the underlying phase-space topology by varying the chain length and the size of the kinetic-temperature difference.     

Interferometrische Bestimmung der Ultraschallgeschwindigkeit in binären flüssigen Mischungen von Nichtelektrolyten, 2. Mitt.:

Zusammenfassung Es werden die Schallgeschwindigkeiten in den Systemen Chlorex®-Cyclohexan, 1,2-Dibromäthan-Benzol und 1,1,2,2-Tetrachloräthan-Diäthylketon bei etwa 2 MHz bei 20° und 30°C mitgeteilt. Die Messungen erfolgten mit einem früher beschriebenen¹ registrierenden Ultraschallinterferometer. Der Schwingquarz wurde außerhalb des Meßraumes angebracht, indem er mit einer planparallelen Metallplatte optimaler Dicke verklebt wurde (Verbundschwinger), welche den Boden des Meßgefäßes abschließt.

---

The velocities of ultrasonic sound have been determined at about 2 Mc/sec of the binary systems chlorex®-cyclohexane, 1,2-dibromoethane-benzene, and 1,1,2,2-tetrachloroethane-diethylketone at 20° and 30°C, resp. The measurements have been made by means of a registrating interferometer, which has been described previously¹. Now the quartz has been arranged outside of the liquid under investigation, by glueing it onto a planparallel metal plate of optimal thickness, which tightens the bottom of the interferometer.

---

---

Mit 7 Abbildungen     

Fission neutron therapy at FRM II: Indications and first results

Based on 15 years of experience with neutron therapy at the former facility at Munich research reactor FRM, fast neutron therapy with fission neutrons of FRM II is performed at the new facility MedApp since June 2007. General indications are superficially located tumors with insufficient response to conventional radiotherapy. Until August 2009, 58 patients were treated, 25% of them with curative intention (adenoid cystic carcinoma of major salivary glands, malignant melanoma, sarcoma). The most frequent palliative indications were breast wall recurrences of breast cancer and skin or lymph node recurrences of squamous cell carcinomas, resulting in response rates of 84% and 42%, respectively. Short treatment times of fast neutron therapy (3–5 fractions in 2–3 weeks) are advantageous in palliative treatment strategies.     

Polyphosphazene Based Star‐Branched and Dendritic Molecular Brushes

A new synthetic procedure is described for the preparation of poly(organo)phosphazenes with star‐branched and star dendritic molecular brush type structures, thus describing the first time it has been possible to prepare controlled, highly branched architectures for this type of polymer. Furthermore, as a result of the extremely high‐arm density generated by the phosphazene repeat unit, the second‐generation structures represent quite unique architectures for any type of polymer. Using two relativity straight forward iterative syntheses it is possible to prepare globular highly branched polymers with up to 30 000 functional end groups, while keeping relatively narrow polydispersities (1.2–1.6). Phosphine mediated polymerization of chlorophosphoranimine is first used to prepare three‐arm star polymers. Subsequent substitution with diphenylphosphine moieties gives poly(organo)phosphazenes to function as multifunctional macroinitiators for the growth of a second generation of polyphosphazene arms. Macrosubstitution with Jeffamine oligomers gives a series of large, water soluble branched macromolecules with high‐arm density and hydrodynamic diameters between 10 and 70 nm.