Recognition and classification of structure by means of stereological methods in neurobiology

The problem of measuring fine structure of individual particles without losing information on largescale characteristics of particle arrangement is discussed. With the help of stereological and pattern recognition methods a possible solution of this important problem is introduced. The domain specimen for which the brain serves as an example is characterized by two main properties. One of them being the position dependent ‘aggregate characteristics’ (distribution of neurons within the specimen), the other position invariant ‘single cell characteristics’ (structural properties of single neurons). It is shown that by simultaneous observation both properties together cannot be detected with sufficient accuracy by conventional methods. This is the decisive problem of ‘correlation microscopy’. The method described in this paper is based on selection of the most informative variables and selection of subdomains (e.g. sections and reference planes). This results in a very general probabilistic concept in modern stereology, offering solutions to complex structure classification problems in biology.     

Exploring possible connections between tribology and osteoarthritis

This paper is part of a continuing study aimed at exploring possible connections between tribology and mechanisms of synovial joint lubrication and degeneration. In a separate paper, the focus was on the tribological behaviour of natural and ‘normal’ synovial joints. The central thrust or purpose of the present paper is to stimulate discussion of ‘abnormal’ joint behaviour, in particular, degenerative joint disease or osteoarthritis, from the point of view of a tribologist, and in the light of our findings on cartilage wear. Some provocative questions are raised. For example, can a lack of ‘proper’ synovial joint lubrication or a specific biochemical ‘anti-wear’ agent lead to degeneration of the joint or more rapid removal of articular cartilage? Does osteoarthritic articular cartilage have poorer resistance to wear than ‘normal’ cartilage? It is not argued that arthritis is a tribological problem. However, it would seem that tribological connections with degenerative joint disease — and possibly other forms of arthritis — are indeed possible, but complex.     

Intensity gradient techniques for orientation analysis of electron micrographs

The variation in intensity between neighbouring picture points on an electron micrograph may be used to define an intensity gradient vector. This vector is related to the orientation of the feature at that point, and may be compared with similar vectors at all other points within the micrograph to obtain a quantitative measure of anisotropy. Alternatively, the results may be displayed graphically as a rosette diagram. This paper compares the results from using a simple ‘5-point’, i.e. the nearest neighbours with those from alternative formulations for the intensity gradient vector. Generally, the increased number of points improves the shape of the rosette diagram by minimizing the likelihood of pronounced ‘spikes’ at certain critical angles which is a feature of the ‘5-point’ method. The improved analysis requires an extra 60% computing time, which may be of significance if direct on-line work is contemplated. Some examples of micrographs of soil microfabric are presented to illustrate the different methods.     

Demonstrating the importance of using total time balance instead of route balance on a multi-objective vehicle routing problem with time windows

‘Route balance’ is the difference between the longest and the shortest among all the route lengths. The route balance is frequently considered in a vehicle routing problem (VRP) for balancing the distance travelled among delivery vehicles. This is a common practice since in VRPs there are no time elements. However, in recent years, some research works have considered route balance in a vehicle routing problem with time windows (VRPTW). As there are more time elements in VRPTW, this paper refutes that route balance is sufficient for VRPTW by simultaneously optimising makespan and workload imbalance using ‘total time balance’ instead of route balance. On the other hand, ‘total time balance’ is the difference between the longest total time taken and the shortest total time taken among delivery vehicles. As such, makespan is the longest total time taken among vehicles. Total time taken for a vehicle is the sum of vehicle run time, waiting time and service time. In order to demonstrate the importance of using total time balance instead of route balance on VRPTW, three different multi-objective VRPTW models, namely, (1) only with general VRPTW objectives (i.e. ‘total distance travelled’ by all vehicles and ‘total number of vehicles’ used), (2) general VRPTW objectives with route balance and (3) general VRPTW objectives with total time balance are developed and solved by fitness aggregated genetic algorithm (FAGA) for 36 Solomon’s benchmark instances. By comparison of the makespan produced by the FAGA between the three cases, the importance of using total time balance instead of route balance on multi-objective VRPTW is demonstrated. Also, the makespan produced by the FAGA for the third case, i.e. general VRPTW objectives with total time balance is compared with the makespan produced by fitness aggregated differential evolution (FADE). By comparing makespan with statistical testing between FAGA and FADE, the outperformance of FAGA over FADE is verified. To check the practicality of the total time balance on multi-objective VRPTW, an instance with real time windows is also solved for the three cases by the FAGA and its makespan are compared and reported.     

High‐precision positioning and measurement systems for microtribotesting

A key problem in microtribology is measurement equipment in the micronewton force regime. This work reports on a new generation of test devices for materials research that closes the gap existing between the so‐called ‘macrotribometers’ and ‘nanotribometers’. The systems incorporate novel mechatronic systems for force measurements based on a combination of photostructured glass and high‐resolution fiber‐optic sensors. In addition, precision drives operating at high speed enable rapid sample positioning and sample motion in different modes. The flexibility of the concept allows tribological examinations of a wide variety of materials and material pairings to be performed with various geometrical configurations. An important feature of the system is modularity, which gives the researcher tremendous flexibility in designing experiments. Furthermore, such systems can easily be added in multi‐analysis environments. Modularity is realized at the hardware level by the possibility of rapidly exchanging drive modules and/or force transducer(s) depending on the user‐defined measurement requirements. Also, the test equipment presented can operate in a wide normal and tangential force regime (exchange of measurement head, force transducer) as well as in different motion configurations. It thus bridges the gap between ‘macro’ and ‘nano’ measurement systems. Copyright © 2006 John Wiley & Sons, Ltd.     

Silicone fluids: Synthesis,properties and applications

This paper describes the structure and derivation of ‘classical’ silicone fluids, giving the reactions for the production of dimethyl fluids by Miiller-Rochow synthesis, polymerisation, direct synthesis, hydrosilylation, and transesterification. The properties of siloxanes are described, and the applications of silicone fluids and compounds are discussed in relation to their properties, particularly insolubility in water, viscosity-temperature characteristics, and dielectric properties.     

A simple method to estimate the true diameter of synaptic vesicles

The problem of estimating the full diameter of synaptic vesicles from the diameter of their profiles in section is approached by calculating the respective difference in simulated size distributions. This difference increases linearly to the quotient Da/T (the ‘apparent’ mean diameter and the thickness of section). Knowing Da/T the observer can add the corresponding percentage proportion given in this paper to the measured mean diameter (Da) in order to get the ‘true’ diameter in a vesicle population.     

Liquid nitrogen-based quick freezing: Experiences with bounce-free delivery of cholinergic nerve terminals to a metal surface

The limitations of chemical fixation in permitting the 1:1 quantitative correlations required for convincing ultrastructural explanations of cell biological processes are noted. We describe techniques for obtaining highly reproducible direct quick freezing on the polished surface of pure copper bars dipping into a static dewar of liquid N₂. The importance and the ease of testing and obtaining bounce suppression with commerically available equipment is emphasized. Artefacts caused by tissue damage and bad freezing are illustrated, and a hitherto unrecognized population of presynaptic membrane attached vesicles is described in Torpedine electric organ. Between 15 and 20% of the synaptic vesicles are attached to ca. 30% of the cytoplasmic face of the presynaptic terminal membrane. There is a close correlation between the occurrence of such attachments and the application of electrocyte basal lamina to the external face. We suggest that these vesicles are the ‘membrane operators,’ ‘vesigates,’ and ‘highly active subpopulation’ of vesicles whose existence has been invoked to explain biochemical data in other laboratories. We further speculate that relatively selective Ca pumping by this immediately submembranous population leads to displacement of acetylcholine (ACh) and reloading with newly synthesized ACh. The preferential release of the latter would then be expected.     

面向性能需求的系统问题分析及确定方法研究

问题分析和问题确定是问题解决的前提基础,而性能需求是产品设计的起点和终点,是设计产品不断升级的驱动力,因此将性能需求应用于系统问题分析过程中,以功能作为桥梁建立性能需求与产品结构的对应关系,确定系统未满足的功能需求,并通过构建系统的局部功能关系模型,结合根原因分析确定系统的问题结构;构建了产品创新的系统问题分析及确定过程模型,并应用该模型进行大蒜去皮设备的创新设计,验证了该方法的有效性和实用性。     

Thermostatic tissue platform for intravital microscopy: 'the hanging drop' model

Intravital microscopy imposes the particular problem of the combined control of the body temperature of the animal and the local temperature of the observed organ or tissues. We constructed and tested, in the rat ileum microcirculation preparation, a new organ‐support platform. The platform consisted of an organ bath filled with physiological solution, and contained a suction tube, a superfusion tube, an intestine‐support hand that was attached to a micromanipulator and a thermometer probe. To cover the intestine we used a cover glass plate with a plastic ring glued on its upper surface. After a routine procedure (anaesthesia, monitoring and surgery), the intestine segment (2–3 cm long) was gently exteriorized and placed on the ‘hand’ of the organ support. A small part of the intestine formed a small ‘island’ in the bath that was filled with physiological salt solution. The cover glass was secured in place. The physiological salt solution from the superfusion tube, which was pointed to the lower surface of the cover glass, formed a ‘hanging drop’. The objective of the microscope was then immersed into distilled water that was formed by the cover glass plastic ring. The ‘hanging drop’ technique prevented any tissue quenching, ensured undisturbed microcirculation, provided for stable temperature and humidity, and permitted a clear visual field.     

Static and dynamic experiments in cryo-electron microscopy: comparative observations using high-vacuum, low-voltage and low-vacuum SEM

We carried out a unique comparative study between three modes of cryo‐scanning electron imaging: high‐vacuum, low‐voltage and low‐vacuum, using ice cream as a model system. Specimens were investigated both with and without a conductive coating (Au/Pd) and at temperatures for which ice either remains fully frozen (< ?110 °C) or undergoes sublimation (?110 to ?90 °C). At high magnification, high‐vacuum imaging of coated specimens gave the best results for ‘static’ specimens (i.e. containing fully frozen ice). Low voltages, such as 1 kV, could be used for imaging uncoated specimens at high vacuum, although slight ‘classical’ charging artefacts remained an issue, and the reduced electron beam penetration tended to decrease the definition between different microstructural features. However, this mode was useful for observing in situ sublimation from uncoated specimens. Low‐vacuum mode, involving small partial pressures of nitrogen gas, was particularly suited to in situ sublimation work: when sublimation was carried out in low vacuum in the absence of an anti‐contaminator plate, sublimation rates were significantly reduced. This is attributed to a small partial pressure of sublimated water vapour remaining near the specimen surface, enhancing thermodynamic stability.     

Development of a meta-stable semi-synthetic lubricant for cold rolling of steel

A semi-synthetic meta-stable oil system for cold rolling of steel was developed as a substitute for a mineral oil based ‘stable emulsion’-type soluble oil. The developed oil system, comprising a ‘coating oil’ for post-pickling application and a ‘rolling oil’ for the rolling operation, was tested in the laboratory and subsequently subjected to extensive field trials in an integrated steel plant. Use of the developed oil system resulted in 25–50 per cent lower roll loads and 30–50 per cent reduction of inter-stand tensions compared with the mineral oil-based ‘stable emulsion’. It was also possible to increase the ‘strip reduction ratio’ and input coil width with the use of the newly-developed oil. Overall performance of the new semi-synthetic oil was found to be far superior to that of the mineral oil based ‘stable emulsion’.     

两种甜樱桃果实挥发性成分的HS-SPME-GC/MS分析

采用顶空固相微萃取(HS-SPME)技术提取"红灯"和"巨红13-38"两种甜樱桃成熟期果实的挥发性成分,经气相色谱-质谱(GC/MS)联用仪测定,比较分析两种甜樱桃果实的香气成分变化。结果表明:两种甜樱桃中共检测出68种香气成分,其中,在"红灯"甜樱桃中检测出29种香气成分,主要为醛类、醇类和酯类,分别占鉴定物质总量的34.25%、32.00%和30.77%;在"巨红"甜樱桃中检测出50种香气成分,主要为萜类、醇类、脂类化合物,分别占鉴定物质总量的78.41%、10.47%和5.29%。"红灯"和"巨红"香气种类及含量存在很大差异,两种甜樱桃果实只有10种共有香气成分,"红灯"中相对含量较高的物质是苯甲醛、苯甲醇、乙酸乙酯和(E)-2-己烯醇,可作为其特征香气;巨红中相对含量较高的物质为石竹烯,达41.8%,其次为顺-氧化芳樟醇和葎草烯。     

A new technique for making plant epidermal imprints using various domestic adhesives

A simple, quick and easy method for making leaf surface imprints for microscopic studies by using cheap and easily available non-toxic domestic adhesives is described. The most satisfactory results were obtained, in order of preference, by using ‘Quickfix’, ‘Stickfast’, ‘Fevicol’, ‘D.P.X. (mountant)’, ‘Camel paste’, ‘Cello-tape’ and ‘Araldite’. These were used on the epidermis of vegetative and floral organs of a number of plants (living and dried). A semi-transparent film was allowed to dry, which was then stripped off and mounted on a clean slide. This film records very fine structural details which are evident from the photomicrographs presented. With the help of this technique, the form, distribution and orientation of stomata, size of guard cells and their movement, size of stomatal pores, stomatal development, cell-wall nature, stomatal frequency and indices and venation pattern can easily be studied. Repeated imprints can be made from the same surface of an organ. This method should be of great use to plant morphologists and anatomists.     

A data model for an assembly planning software system

A simple data model for assembly planning as a foundation for the construction of an innovative task-based assembly planning software system has been designed. The model uses ‘assembly task’ as its central object to which associations with other assembly objects such as ‘part’, ‘assembly’, ‘assembly machine’ and ‘assembly tool’ are made. It was used to derive a data template-based database schema for all assembly planning functions of the software system. The schema was connected with the software system's front end user interface by pictorial data glyphs. The assembly planning model, the database schema, the user interfaces and the connectivity between the schema and the user interfaces are described.     

Negative staining of viruses

Several techniques and procedures of negative staining are described and compared from the point of view of both ‘drying’ and ‘specific staining’ artefacts. These are shown on examples from several virus species. The ‘drying artefacts’ can be prevented using the freeze-drying technique or reduced using ‘paper-filtration’, ‘pseudoreplication’ or the Kleinschmidt techniques. The ‘specific staining’ artefacts can be avoided by using another stain which does not affect the structure under study. Different ways are shown to stain the surface or the interior of virus particles.     

Investigation into the wear behaviour of Stellite 6 during rotation as an unlubricated bearing at 600 °C

The wear behaviour of Stellite 6 was studied during rotational sliding in a bespoke bearing rig at 600 °C for times between 2 min and 12 h. Six stages of wear were identified: (i) formation of a mixed oxide ‘glaze’, (ii) cobalt and chromium elemental diffusion to the ‘glaze’ surface forming chromium- and cobalt-dominated oxide layers, (iii) oxygen diffusion into the ‘glaze’ leading to a chromium-dominated oxide layer at the ‘glaze’/substrate interface, (iv) spallation of the ‘glaze’ through chemical failure, (v) re-formation of the ‘glaze’ and (vi) elemental diffusion within the ‘glaze’, again resulting in discrete oxide layer formation.     

租赁车辆运输外包模式下多次直接运输策略的集成库存运输计划

分销网络在车辆租赁运输外包模式下,如何协调同步库存和运输计划是需要确定的运作决策.为此,讨论了多产品、单分销商、多用户的分销网络中,分销中心在租赁车辆外包模式和多次直接运输策略下的配送计划问题,建立了该问题的混合整数规划模型MTDS-ⅡT.根据问题的特点,设计并开发了基于部分链的遗传算法,以求解该模型.     

Permanent preparations of stained whole-body sections using 'Trycolac'

Permanent preparations of whole-body sections cut by Ullberg's technique can be prepared using a ‘spray-on’ mountant (‘Trycolac’), which does away with the necessity for glass slides and coverslips. Routine staining methods can be used, providing the alcohol content of the stain is low. Glycerol is used for dehydration and clearing and a covering of ‘Trycolac’ is sprayed on.     

A numerical analysis method based on flow continuity for hydrodynamic journal bearings

A numerical method of hydrodynamic bearing analysis is presented which is simple in concept, yet capable of development to handle complex situations such as dynamic misalignment. It is similar to the finite difference solution of Reynolds equation, but incorporates a more realistic modelling of cavitation. The approach to a numerical solution is direct, and should facilitate a better ‘feel’ for the way in which the physical processes are modelled. Results produced with this analysis are compared with other published data for aligned crankshaft bearings and misaligned sterntube bearings.