SUMMARY A method for accurate three‐dimensional reconstruction of openly connected porous structures is described. The method is based on embedding of a specimen in a contrast coloured epoxy resin and serial sectioning in a standard hard tissue microtome. A PC‐based image processing system is used for direct digitization of the cut surface, and by thresholding two‐phase images are obtained. The process is fully automated, and about 170 sections can be produced, digitized, dichotomized, and stored per hour. As an example of its applications, the method is used on trabecular bone, which is an anisotropic porous structure.

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The importance of the medial and lateral compartment ligaments of the knee in relation to valgus-varus and axial rotation instability was investigated. Mobility patterns were drawn from 20 osteoligamentous knee preparations after successive transections of the structures. Cutting of the medial collateral ligament resulted only in slight valgus instability and modest anteromedial instability. When the medial posterior joint capsule was also cut, both types of instability increased, and moreover, the knee became posteromedially unstable. Cutting of the lateral collateral ligament produced only a little varus instability and anterolateral rotatory instability, but varus instability increased considerably when the posterior lateral capsule was also transected. In this latter situation, even marked posterolateral rotatory instability was found. Isolated transection of the medial or lateral collateral ligament did not cause any major valgus or varus instability, but when the posterior capsule was also transected, a considerable degree rotatory instability could be found even though the cruciate ligaments were intact.

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Published version Kirsebom, O. S.; Hukkanen, M.; Kankainen, A.; Trzaska, W. H.; Strömberg, D. F.; Martínez-Pinedo, G.; Andersen, K.; Bodewits, E.; Brown, B. A.; Canete, L.; Cederkäll, J.; Enqvist, T.; Eronen, T.; Fynbo, H. O. U.; Geldhof, S.; de Groote, R., Jenkins, D. G.; Jokinen, A.; Joshi, P.; Khanam, A.; Kostensalo, J.; Kuusiniemi, P.; Langanke, K.; Moore, I.; Munch, M.; Nesterenko, D. A.; Ovejas, J. D.; Penttilä, H.; Pohjalainen, I.; Reponen, M.; Rinta-Antila, S.; Riisager, K.; de Roubin, A.; Schotanus, P.; Srivastava, P. C.; Suhonen, J.; Swartz, J. A.; Tengblad, O.; Vilen, M.; Vínals, S.; Äystö, J. Kirsebom, O. S.; Hukkanen, M.; Kankainen, A.; Trzaska, W. H.; Strömberg, D. F.; Martínez-Pinedo, G.; Andersen, K.; Bodewits, E.; Brown, B. A.; Canete, L.; Cederkäll, J.; Enqvist, T.; Eronen, T. et al. (2019). Measurement of the 2+→0+ ground-state transition in the β decay of 20F.We report the first detection of the second-forbidden, nonunique, 2 + → 0 + , ground-state transition in the β decay of 20 F. A low-energy, mass-separated 20 F + beam produced at the IGISOL facility in Jyväskylä, Finland, was implanted in a thin carbon foil and the β spectrum measured using a magnetic transporter and a plasticscintillator detector. The β-decay branching ratio inferred from the measurement is b β = [0.41 ± 0.08(stat) ± 0.07(sys)] × 10 −5 corresponding to log f t = 10.89(11), making this one of the strongest second-forbidden, nonunique β transitions ever measured. The experimental result is supported by shell-model calculations and has significant implications for the final evolution of stars that develop degenerate oxygen-neon cores. Using the new experimental data, we argue that the astrophysical electron-capture rate on 20 Ne is now known to within better than 25% at the relevant temperatures and densities.

Experimental binding equilibrium data, resulting from measurement of ligand binding to macromolecular carriers, are usually described by fitting of binding constants. These constants are often highly variable, as illustrated in the present paper by two examples, binding of salicylate to human serum albumin and of oxygen to hemoglobin. In order to avoid over-interpretation of binding constants it is pointed out that the best-fit solution, obtained by least-squares fitting, may be supplemented by several, e. g. thirty, acceptable solutions. It is further shown how the 30 sets of acceptable binding constants, plotted as Klotz' affinity profiles, can serve for evaluation of cooperative effects.Multiple binding equilibria for a ligand to a macromolecular carrier are usually characterized by a set of binding constants, parameters in a binding equation. Such a set of binding constants may serve two purposes, comparison with results from other binding equilibrium studies, and considerations of interactions, i. e. whether binding is cooperative, homogeneous or anticooperative. It is essential for these purposes to have a knowledge of the variation of the binding constants, as originating from the random errors of the observed data.The present paper evaluates the variation of multiple binding constants. Two experimental materials are analysed: data for the binding of salicylate anion to human serum albumin, from equilibrium dialysis measurements, and oxygenhemoglobin data, as published by Winslow et al. [l]. It is shown that the data can be presented by a multitude of fitted isotherms with highly variable binding constants. The results are utilized for consideration of binding interactions. MATERIALS AND METHODSHuman serum albumin was obtained from AB Kabi (Stockholm, Sweden) and was defatted with charcoal in acid solution [2] and lyophilized. Binding equilibria with sodium salicylate were studied by equilibrium dialysis as previously described [3] in a 0.1 M Tris/HCl buffer with 0.1 M sodium chloride, pH 8.2, at 25°C. The time needed for establishing cquilihriiiin was about 8 h; 20 h dialysis time was allowed. absorbance in a 0.5-cm cell at the wavelength 296 nm. It was found that the absorbance was proportional to the concentration within the range of concentrations used. 0 -2 mM, showing the absence of ligand dimerisation. The molar absorption coefficient was 3530 M-' cm-'. Albumin concentration was 100 pM. Errors from binding of salicylate to the membrane and from compartment volume changes were found to be negligible as were a number of other sources of technical errors previously discussed [3]. Free and bound equilibrium concentrations of salicylate were calculated and plotted as r, the concentration of bound salicylate divided by that of albumin, versus the logarithm of the free salicylate concentration. Additional points obtained with varying albumin concentrations, from 100 pM to 1000 pM, were apparently located on the same curve, indicating the absence of albumin-albumin interaction.Equilibrium data for binding ...