硝苯啶的光解分析法及其在透皮吸收研究中的应用

A new method of analysis for low concentrations nifedipine was developed according to the principle of a photodegradation analytical method that has been reported by the authors previously, and was used to study percutaneous absorption. The absorbance of sample solution was measured before and after light irradiation at 237 nm for 2 h. In this method, calibration graph was linear in the range of 1～20μg/ml for △A₂₃₇. The average recovery for nifedipine was 98.80%. No interference from propylene glycol, azone, m-nifedipine, nitrendipine, verapamil and propranolol was observed. It is shown that azone can promote markedly percutaneous absorption of nifedipine.     

Images from Waves — photoelastic modelling of bones

Background This paper cites the development of the principles of photoelastic stress analysis, contemporary to the life of Samuel Haughton. Subsequent studies of bone and joint replacements are discussed, with reference to hypotheses regarding bone, including the coincidence of trabecular structure with principal stresses. Issues regarding assumptions of homogeneous and isotropic properties in photoelastic modelling are acknowledged. Aim Awareness of photoelastic methods is often through the visual appeal of the coloured fringe patterns. The aim of this paper is to complement this awareness by demonstration of the quantitative analyses that may be conducted through biomechanical examples. Methods Examples of new pseudo three-dimensional model analyses are presented together with a method for photoelastic study of cancellous bone, which entails novel procedures for preparation of replicate models and for optical evaluation of fringes. Conclusion Photoelastic analysis offers novel solutions to studies in biomechanics, which are facilitated by contemporary modelling materials.     

Epitope-function relationships of human leukemia inhibitory factor receptors using a novel set of anti-gp190 mAB

The binding and functional properties of a set of six mAb directed against the human gp190 [leukemia inhibitory factor (LIF) receptor] signal transducing molecule were determined. Each of the antibodies reacted with a distinct epitope on gp190 expressed either by gp190- transfected Chinese hamster ovary cells or by the LIF receptor-positive choriocarcinoma JAR cell line. Two of the antibodies (1B4 and 6E6) had binding stoichiometries that were approximately 2-fold lower than those of other mAb (10B2, 12D9 and 7G7), suggesting either that gp190 is present as a pre-associated homodimer in the cell membrane or that part of gp190 is pre-associated with another component. Two mAb (1C7 and 1B4) were found to inhibit LIF binding on the two cell types studied. On JAR cells, this inhibition was, however, restricted to the high- affinity LIF component, suggesting different modes of LIF engagement with the low- and high-affinity receptor species. mAb 1C7 and 1B4 were also found to synergize for inhibiting LIF high-affinity binding. This synergy also extended to the inhibition of LIF- or oncostatin M (OSM)- induced proliferation of a Ba/F3 cell line co-transfected with human gp130 and gp190. However, this mAb combination inhibited LIF- but not OSM-induced haptoglobin secretion by HepG2 cells, suggesting that whereas haptoglobin secretion induced by LIF involves gp130/gp190 common LIF/OSM type I receptors, that induced by OSM mainly involves type II OSM receptors.      

Length of the follicular phase, time of insemination, coital rate and the sex of offspring

The penetrability of cervical mucus improves over the follicular phase. When the length of the follicular phase varies due to variation in the timing of the luteinizing hormone surge, mucus penetrability will also improve as the phase lengthens. As selection for Y spermatozoa decreases with improvements in mucus penetrability, sex ratios at conception should decline in longer follicular phases. Sex ratios should also decline as the time of insemination approaches ovulation unless hormonally-induced improvements in penetrability are reduced by the debris left by earlier inseminations.