Semi-automated measurement of true chord length distributions and moments by video microscopy and image analysis

The distribution of the lengths of airspace chords in pulmonary parenchyma characterizes many architectural features of the alveoli and alveolar ducts. Laborious to obtain manually, the distributions and density functions may be acquired semi-automatically by video microscopy, digitization and image processing. The accuracy of the estimation is influenced by the microscopical methods and also by the techniques used (i) to convert the digitized grey-scale picture to a two-valued image, (ii) to collect the chord lengths and (iii) to compensate for finite field widths. The last problem arises because some chords are completely visible within a field while others are only partially seen, since one of the two air-tissue boundaries lies outside the field of view. This error systematically biases the observed distribution. This paper contains solutions to hardware, software and analytic problems encountered while developing the capability to measure airspace chord length density functions semi-automatically. Formulas for estimating the true chord length density function from samples of observed chord lengths are presented. Also given are formulas for the estimation of the first and second moments of the true chord length distribution from the means of observed chord lengths. These techniques of image preparation and analysis should be suitable for characterizing particle, grain or cell size distributions, especially where many profiles fall partially outside the field of view.     

An acoustic tensile load cell able to operate under high water pressures

The principles of operation and the experimental equipment used during an investigation into the role of percolating water within concrete and rock, have been outlined. Attention has been drawn to a problem of measuring a friction force which, if not resolved, would have compromised the investigation. The design requirements of a simple acoustic tensile load cell, capable of resolving the problem, are listed with details of its design, construction and satisfactory performance.     

THE SHEAR FORCE OF VERY-RAPIDLY CHILLED LAMB 2: THE EFFECT OF MUSCLE EXCISION

The effect of chilling rate and muscle excision on the shear force of ovine muscle (M. longissimus thoracis et lumborum) was examined. Conventional chilling involved chilling at 4C for 24 h and very-rapid chilling involved chilling at −20C for 3.5 h followed by conventional chilling for 20.5 h. After 24 h all muscles were aged for a further four days. Approximately 30 min after slaughter, one M. longissimus thoracis et lumborum was excised from each carcass and placed in the same chill as the remainder of the carcass. This gave a total of four different treatments. Shear force was assessed at I and 5 days postmortem by Warner-Bratzler shear force measurement. Excision led to reduced shear force in the very-rapid chilling regime but increased shear force in the conventionally chilled muscles. Aging improved shear force for all chilling treatments. No significant difference was found in the rate of pH fall, between the chilling treatments.     

为进行能源管理并强化车体结构所采用的结构胶黏剂

结构胶黏剂是汽车制造过程中一种日趋重要的金属连接方式。介绍了汉高公司开发的一种汽车用结构胶黏剂的性能特点及应用工艺要求。通过实验证明结构胶黏剂对于提高车体结构性能、减轻车体质量、简化生产过程和优化生产成本来说,是一种十分有用的材料。     

A cell suspension agar diffusion test using Neutral Red release to assess the relative irritancy potential of cosmetic ingredients and formulations

An established cytotoxicity test for plastic materials in medical devices has been adapted and used to assess the relative potential irritancy of cosmetic ingredients and formulations during product development. Serum-free medium containing a novel protein supplement supported growth in suspension of LS mouse fibroblast cells. Release of the vital dye Neutral Red from pre-loaded cells suspended in agar was the endpoint. Test substances and reference standards were applied to a central well cut into the agar, a sensitive method which allowed accurate dose application and yielded consistent results. Relative irritancy potential was measured quantitatively by comparing the diameters of the clear zones of damaged cells which surround the central well. The test has been used with raw materials such as surfactants, preservatives and herbal extracts, as well as finished products ranging from shampoos and conditioners to creams, lotions and coloured cosmetics. The method is practical, versatile, reproducible and economic to use.     

Histological analysis of pollen-pistil interactions in sour passion fruit plants (Passiflora edulis Sims)

The success of sexual plant reproduction is directly influenced by specific interactions between the pollen and pistil. Light, fluorescence and scanning electron microscopy techniques were used to evaluate the steps of pollination in sour passion fruit plants (Passiflora edulis Sims). In the compatible interaction, pollen tubes grow through stigma projections towards the ovary. The pollen grain surface was found to be spheroidal and to consist of heteroreticulate exine with six colpi. Furthermore, analysis in vivo of pollenpistil interactions indicated that stigmas of flowers 24 hours before anthesis are unable to discriminate compatible (genetically unrelated) and incompatible (genetically related) pollen grains. Taken together, these results provide insight into the cellular mechanisms underlying pollination in passion fruit plants.