CFA-15 - a perfluorinated metal-organic framework with linear 1-D CuII-chains containing accessible unsaturated, reactive metal centres.

The synthesis and crystal structure of the perfluorinated metal-organic framework CFA-15 (Coordination Framework Augsburg University-15), CuII3(tfpc)2(OH)2·DMF, as well as the crystal structure of its ligand (H2-tfpc = 3,5-bis(trifluoromethyl)-1H-pyrazole-4-carboxylic acid) are described. The MOF crystallizes in the monoclinic crystal system within the chiral space group C2 (no. 5). It features a 3-D microporous framework with rhombic channels along the c-axis. The MOF is formed by 1-D chains of Cu(ii) ions expanding in the c-direction, bridged by OH- groups, DMF molecules and tfpc2- ligands. Two different Cu(ii) species are located within the structure, bridged in a {Cu1-Cu1-Cu2-Cu1-Cu1-Cu2} mode. By thermal treatment, it was possible to remove coordinated solvent molecules and generate free accessible, unsaturated and reactive metal centres. The structure of activated CFA-15 was refined via Rietveld method. DRIFT measurements, which were used to study adsorption of CO2 and NO in the MOF, showed a formation of a stable NO-CFA-15 complex. CFA-15 was further characterized by thermogravimetric analysis, variable temperature powder X-ray diffraction measurements, IR spectroscopy, as well as photoluminescence and gas sorption measurements. The isosteric heats of adsorption for CO, CO2, H2 and O2 were determined, and compared to DFT calculated sorption energies as well as to data reported in literature for similar materials.

CFA-14 - a perfluorinated metal-organic framework with linear 1-D CoII-chains showing temperature dependent spin-chain magnetic ordering.

The synthesis and crystal structure of the perfluorinated metal-organic framework (MOF) CFA-14 (Coordination Framework Augsburg University-14), CoII2(tfpb)(OH)2 (H2-tfpb = 1,4-bis(3,5-bis(trifluoromethyl)-1H-pyrazole-4-yl)benzene) are described. The cobalt-containing MOF crystallizes in the tetragonal crystal system within the space group I41/acd (no. 142) and the unit cell parameters are as follows: a = 20.3213(11) Å, c = 12.4045(8) Å, V = 5122.5(6) Å3. CFA-14 features a porous two-fold interpenetrated 3-D microporous structure constructed from 1-D chains of cobalt(ii) ions expanding in the c-direction, bridged by OH- groups and tfpb2- ligands. The structure exhibits quadratic channels running along the c-axis. CFA-14 is fully characterized by synchrotron single crystal X-ray diffraction, thermogravimetric analysis, variable temperature powder X-ray diffraction, IR- and UV-Vis spectroscopy, photoluminescence and gas sorption measurements. Moreover, the magnetic properties of CFA-14 are examined via SQUID measurements.

Hairpins in the conformations of a confined polymer.

If a semiflexible polymer confined to a narrow channel bends around by 180°, the polymer is said to exhibit a hairpin. The equilibrium extension statistics of the confined polymer are well understood when hairpins are vanishingly rare or when they are plentiful. Here, we analyze the extension statistics in the intermediate situation via experiments with DNA coated by the protein RecA, which enhances the stiffness of the DNA molecule by approximately one order of magnitude. We find that the extension distribution is highly non-Gaussian, in good agreement with Monte-Carlo simulations of confined discrete wormlike chains. We develop a simple model that qualitatively explains the form of the extension distribution. The model shows that the tail of the distribution at short extensions is determined by conformations with one hairpin.

CFA-13 - a bifunctional perfluorinated metal-organic framework featuring active Cu(i) and Cu(ii) sites.

The synthesis and crystal structure of the mixed-valent perfluorinated metal-organic framework (Me2NH2)[CFA-13] (Coordination Framework Augsburg University-13), (Me2NH2)[CuCu(tfpc)4] (H2-tfpc = 3,5-bis(trifluoromethyl)-1H-pyrazole-4-carboxylic acid) is described. The copper-containing MOF crystallizes in the monoclinic crystal system within the space group P21/n (no. 14) and the unit cell parameters are as follows: a = 22.3887(19), b = 13.6888(8), c = 21.1804(13) Å, ß = 90.495(3)°, V = 6491.0(8) Å3. (Me2NH2)[CFA-13] features a porous 3-D structure constructed from two types of secondary building units (SBUs). Besides novel trinuclear [Cu(pz)4]- coordination units, the network also exhibits Cu(ii) paddle-wheel SBUs. (Me2NH2)[CFA-13] is fully characterized by single crystal X-ray diffraction, thermogravimetric analysis, variable temperature powder X-ray diffraction, IR spectroscopy, photoluminescence, gas sorption measurements and pulse chemisorption experiments. M[CFA-13] (M = K+, Cs+) frameworks were prepared by postsynthetic exchange of interchannel dimethylammonium cations. Moreover, it was shown that CO molecules can be selectively bound at Cu(i) sites of [Cu(pz)4]- units, whereas Cu(ii) paddle-wheel units bind selectively NH3 molecules.

CFA-4 - a fluorinated metal-organic framework with exchangeable interchannel cations.

The syntheses and crystal structures of the fluorinated linker 1,4-bis(3,5-bis(trifluoromethyl)-1H-pyrazole-4-yl)benzene (H2-tfpb; 1) and the novel metal-organic framework family M[CFA-4] (Coordination Framework Augsburg University-4), M[Cu5(tfpb)3] (M = Cu(i), K, Cs, Ca(0.5)), are described. The ligand 1 is fully characterized by single crystal X-ray diffraction, photoluminescence-, NMR-, IR spectroscopy, and mass spectrometry. The copper(i)-containing MOF crystallizes in the hexagonal crystal system within the chiral space group P6322 (no. 182) and the unit cell parameters are as follows: a = 23.630(5) Å, c = 41.390(5) Å, V = 20 015(6) Å3. M[CFA-4] features a porous 3-D structure constructed from pentanuclear copper(i) secondary building units {Cu(pz)6}- (pz = pyrazolate). Cu(I)[CFA-4] is fully characterized by synchrotron single crystal X-ray diffraction, thermogravimetric analysis, variable temperature powder X-ray diffraction, IR spectroscopy, photoluminescence and gas sorption measurements. Moreover, thermal stability and gas sorption properties of K[CFA-4] and Cu(I)[CFA-4] are compared.

Visualizing the entire DNA from a chromosome in a single frame.

The contiguity and phase of sequence information are intrinsic to obtain complete understanding of the genome and its relationship to phenotype. We report the fabrication and application of a novel nanochannel design that folds megabase lengths of genomic DNA into a systematic back-and-forth meandering path. Such meandering nanochannels enabled us to visualize the complete 5.7 Mbp (1 mm) stained DNA length of a Schizosaccharomyces pombe chromosome in a single frame of a CCD. We were able to hold the DNA in situ while implementing partial denaturation to obtain a barcode pattern that we could match to a reference map using the Poland-Scheraga model for DNA melting. The facility to compose such long linear lengths of genomic DNA in one field of view enabled us to directly visualize a repeat motif, count the repeat unit number, and chart its location in the genome by reference to unique barcode motifs found at measurable distances from the repeat. Meandering nanochannel dimensions can easily be tailored to human chromosome scales, which would enable the whole genome to be visualized in seconds.

Fast size-determination of intact bacterial plasmids using nanofluidic channels.

We demonstrate how nanofluidic channels can be used as a tool to rapidly determine the number and sizes of plasmids in bacterial isolates. Each step can be automated at low cost, opening up opportunities for general use in microbiology labs.

Extension of nanoconfined DNA: Quantitative comparison between experiment and theory.

The extension of DNA confined to nanochannels has been studied intensively and in detail. However, quantitative comparisons between experiments and model calculations are difficult because most theoretical predictions involve undetermined prefactors, and because the model parameters (contour length, Kuhn length, effective width) are difficult to compute reliably, leading to substantial uncertainties. Here we use a recent asymptotically exact theory for the DNA extension in the "extended de Gennes regime" that allows us to compare experimental results with theory. For this purpose, we performed experiments measuring the mean DNA extension and its standard deviation while varying the channel geometry, dye intercalation ratio, and ionic strength of the buffer. The experimental results agree very well with theory at high ionic strengths, indicating that the model parameters are reliable. At low ionic strengths, the agreement is less good. We discuss possible reasons. In principle, our approach allows us to measure the Kuhn length and the effective width of a single DNA molecule and more generally of semiflexible polymers in solution.

Structural dynamics and interfacial properties of filler-reinforced elastomers.

The combined effect of filler networking and reduced chain mobility close to the filler interface is analyzed based on investigations of the relaxation dynamics of a solution of styrene butadiene rubber filled with different loadings and types of nanostructured carbon blacks. Dynamic-mechanical and dielectric spectra are studied in a wide frequency and temperature range. By referring to a tunneling process of charge carriers over nanoscopic gaps between adjacent carbon black particles the gap distance is evaluated from the dielectric spectra. This distance corresponds to the length of glassy-like polymer bridges forming flexible bonds between adjacent filler particles of the filler network. It is found that the gap distance decreases with increasing filler loading and specific surface area which correlates with an increase of the apparent activation energy of the filler network evaluated from dynamic-mechanical data. Due to the thermal activation of glassy-like polymer bridges the time-temperature superposition principle is not fulfilled for filled elastomers and the introduction of vertical shift factors is necessary to obtain viscoelastic master curves. The change in the low frequency viscoelastic properties by the incorporation of fillers is shown to be related to the superimposed dynamics of the filler network governed by the viscoelastic response of the glassy-like polymer bridges. This effect is distinguished from the reduced chain mobility close to the filler surface which results in a broadening of the glass transition on the high temperature or low frequency side. The microstructure-based interpretation of viscoelastic data is supported by an analysis of the relaxation time spectra.

Local observation of reverse-domain superconductivity in a superconductor-ferromagnet hybrid.

Nanoscale magnetic and superconducting properties of the superconductor-ferromagnet Nb/PbFe12O19 hybrid were studied as a function of applied magnetic fields. Low-temperature scanning laser microscopy (LTSLM) together with transport measurements were carried out in order to reveal local variations of superconductivity induced by the magnetic field template produced by the ferromagnetic substrate. Room temperature magnetic force microscopy (MFM) was performed and magnetization curves were taken at room and low temperature to investigate the magnetic properties of the hybrid. Comparative analysis of the LTSLM and the MFM images has convincingly demonstrated the presence of the reverse-domain superconductivity.

Zirconium oxide restorations with the DCS precident system.

The DCS Precident system is suitable for the dental practice and enables the processing of different materials and dental structures. The surface is acquired precisely and without contact by means of a semiconductor laser. Easy-to-use software is employed for the three-dimensional design of the restorations. An almost fully automatic milling machine efficiently mills the framework. A clinical case is documented.

[The use of 60Co-gamma ray-sterilized calf serum in cell culture]. / Untersuchungen zum Einsatz 60Co-gamma-Strahlen-sterilisierter Kälberseren in der Zellzucht.

The use of 60Co-gamma-radiation-sterilised calf sera in cell culturing is reported in this paper. Evidence was produced to the effect that 60Co-gamma-irradiation, using a dosage of 3 kGy and a dose rate of 8 kGy/h, of fetal calf serum, neonatal calf serum, and calf serum did not substantially alter the growth-stimulating properties of those sera during 42-day tests. With almost all cell lines and sera used, for all practical purposes, they were identical with the properties of control sera. The following cell lines were used in the experimental programme: one human mammary tumor, MaTu, one human embryonic cell line--E VI, one bat lung cell line--Tb1-Lu, and one human rhabdomyosarcoma--A 204. Growth stimulation was twelve percent below the control value only with Tb1-Lu on Eagle-MEM culturing medium with 3-kGy-irradiation of neonatal calf serum. On the other hand, cell growth was stimulated by 28 percent in A 204 on RPMI 1640 culturing medium, again with 3-kGy-irradiation of neonatal calf serum. Loss of activity by up to 30 percent, depending on the serum used, must be expected from irradiation doses of 10 kGy and 20 kGy which are capable of causing drastic reduction or even complete elimination of serum-borne microorganisms (Bender et al., 1989). Sera irradiated that way would be only conditionally applicable, when it comes to highly vulnerable cell strains.

[The inactivation of mycoplasmas and bacteria in calf serum by 60Co gamma rays]. / Versuche zur Inaktivierung von Mykoplasmen und Bakterien in Kälberseren durch 60Co-gamma-Strahlen.

Reported in this paper is the use of 60Co gamma radiation to inactivate mycoplasmas in calf serum, newborn calf serum, and fetal calf serum. A dose of 3 kGy, independent of dose rate, was found to be sufficient for inactivation in the above sera of several mycoplasmas, including Acholeplasma laidlawii, Mycoplasma (M.) orale, M. arginini, M. hyorhinis, and M. bovis. The critical dose proved to be at 2 kGy. No difference was found to exist between the above species in susceptibility to irradiation in diluted sera (50%) and 10% in Eagle MEM). Sensibility of wild mycoplasma strains was found to be identical with that of laboratory strains. Hence, 60Co gamma irradiation of sera appears to be a safe method by which to make sera mycoplasma-free. Bacillus subtilis in calf serum was inactivated by doses above 18 kGy, with the critical dose being 15 kGy.

[Clinical results following revision of covered goniotrepanation (Elliot-Fronimopoulos)]. / Klinische Ergebnisse nach Revision der gedeckten Goniotrepanation (Elliot-Fronimopoulos).

Among 128 patients with glaucoma, 19 underwent a revision of a goniotrepanation with scleral flap. Adequate regulation of IOP was achieved in this way, in some cases with additional medication. This revision of the filtering bleb can be recommended as the operation of choice for all forms of glaucoma in which goniotrepanation with scleral flap was performed and in which pressure could not be regulated with additional medication.

Early detection of aortic dilatation in ankylosing spondylitis using echocardiography.

Aortic root abnormalities including cusp thickening, subvalvular stenosis, and mild aortic root dilatation are the most common cardiac complications in patients with long standing ankylosing spondylitis (AS). Twenty-three patients with definite idiopathic AS (New York Criteria 1966) and twenty-two matched controls were studied with M-mode echocardiography. Only one of the AS patients had clinical aortic incompetence. Six of the AS patients had mildly dilated aortic roots (normal less than 3.7 cm) with a mean diameter of 3.9 cm (range 3.8 to 4.00 cm). None of the twenty-two controls matched for age, sex and blood pressure had dilated aortic roots, with a mean diameter of 3.3 cm (range 2.9 to 3.6 cm). No correlation existed between aortic dilatation and severity of disease estimated by acute phase proteins--caerulo plasmin, alpha 1-antitrypsin, alpha 1 acid glycoprotein, ferritin and C Reactive protein. Contrary to a previous report, mild aortic root dilatation occurs in long standing cases of AS. Although it is a non-specific finding, it does not appear to be related to age or blood pressure and may therefore be the forerunner of aortic incompetence.

Comparison of iopamidol, ioxaglate, and diatrizoate during coronary arteriography in dogs.

Iopamidol and ioxaglate are two new contrast media which have an osmolality approximately half that of diatrizoate for the same iodine concentration. These three contrast media were compared with each other and with Hartmann's solution during coronary arteriography in dogs using hemodynamic and electrocardiographic parameters in addition to coronary venous sinus sampling to measure changes in osmolality, electrolyte, and contrast media concentration. Iopamidol and ioxaglate had similar, but less toxic, effects in comparison with diatrizoate. These new contrast media may offer a reduction in the morbidity and mortality of coronary arteriography.

Effects of phospholipase A2 and albumin on the calcium-dependent ATPase and the lipid composition of sarcoplasmic membranes.

1. The calcium-dependent ATPase activity of phospholipase-A2-digested sarcoplasmic vesicles decreases concomitantly with the contents of residual lysophospholipids and fatty acids when increasing albumin concentrations are applied. 2. Delipidated albumin preferentially removes unsaturated fatty acids and lysophosphatidylcholine. A complete removal of the phospholipids by albumin does not occur. 3. The membrane-bound lysophospholipids were analysed with respect to type of phospholipid, plasmalogen content and fatty acid chains by means of thin-layer chromatography and gas chromatography. 4. While the fatty acid composition of the lysophospholipids is independent of the degree of delipidation, the composition of the residual free fatty acids is found to change with the albumin concentration. 5. Reactivation of the Ca2+-ATPase by oleate leads to reasonable activities at room temperature as long as a minimum of about 30 lysophospholipid molec-les per ATPase is left. The course of the residual Ca2+-ATPase activity with the degree of delipidation is related to the presence of unsaturated fatty acids. 6. No specific role of either sphingomyelin or the plasmalogens has been found.