The histochemical properties of some periodate-reactive mucosubstances of the pregnant Syrian hamster before and after methylation with methanolic thionyl chloride

The mucosubstances secreted in various tissues of pregnant Syrian hamsters exhibit a wide range of histochemical characteristics. When sections of fixed tissues containing these mucosubstances are treated with a methanolic solution of thionyl chloride for four hours at room temperature, nucleic acid phosphate groups, protein and sialomucin carboxyl groups, and the sulphate groups of many sulphomucins are apparently esterified. In sulphomucins believed to contain carboxyl and sulphate groups, only the sulphate is esterified; the carboxyls (uronic acid groups ?) are left free. If such methylated mucins are saponified (to remove their ester methyl groups) some, but not all, of their histochemical reactions for “free” sulphate are restored. Some desulphation, however, usually occurs during the methylation process. A few sulphated mucins, such as those in the goblet cells of the small intestine, are desulphated completely. The ability to esterify many sulphated mucins without either desulphating them completely or extracting them from the tissue distinguishes methanolic thionyl chloride from the hot methanolic solutions of hydrochloric acid usually used for methylating tissue sections. Moreover, methanolic thionyl chloride solutions are much easier to use. The little chemistry that is at present known about the reactions between methanol and thionyl chloride is insufficient to explain how methanolic thionyl chloride solutions actually methylate polyanionic substances in tissue sections.     

The reflectance factors of a rough ocean with foam—comment on ‘Remote sensing of the sea state using the 0·8-1·1 μm spectral band’ by L. Wald and J. M. Monget

Reflectance factors of a rough ocean surface with and without foam are presented. They are calculated from the Cox-Munk model for an ocean without foam. The isotropic reflectance of oceanic foam is added as function of the wind speed. The effective reflectance of foam patches is taken into account     

IS DETROIT DEAD?

An effective way to understand the slow death of the city of Detroit is through the prism of the course of a terminal disease, tracing the stages of symptom assessment, diagnosis, and curative intervention. This essay explores that notion by taking off from several recent books about Detroit's catastrophic decline that employ the language of urban morbidity and mortality to describe the city's condition. Urban death is a function of the withering or failure of crucial vital urban functions involving, principally, governance and economic opportunity. By that standard the essay concludes that it is becoming hard to call Detroit a living city anymore.     

State estimation of dynamical systems with nonlinearities by using proportional-integral observer

In this paper the application of a PI observer technique to dynamical systems with nonlinearities is proposed. The PI observer has two feedback loops, a proportional loop and an integral loop of the estimation error. In this way the PI observer combines the structures of the practical orientated nonlinearity observer developed by the third author and the classical Luenberger observer. The structure and the estimation performance of the PI observer are discussed and analysed. The results show that the PI observer can estimate the states not only of linear systems, but also, more significantly, of systems with any arbitrary external input which appear as unknown input, nonlinearity or unmodelled dynamics. It is shown that the PI observer works with weak assumptions, which can be fulfilled by many classes of systems to be observed. Owing to the weak assumptions it can improve many observer-based technical solutions as diagnosis or control based on observers. In the paper the conditions are given and proved. The design method is declared and carried out with illustrative examples of a linear system and of a nonlinear system of a link manipulator with flexible joints. The results are good and they show the efficiency of the PI observer. In the case of nonlinear systems the advantages of ‘robustness’ and the model independency of the proposed observer scheme can be shown clearly.     

Comparison of three‐dimensional analysis and stereological techniques for quantifying lithium‐ion battery electrode microstructures

Lithium‐ion battery performance is intrinsically linked to electrode microstructure. Quantitative measurement of key structural parameters of lithium‐ion battery electrode microstructures will enable optimization as well as motivate systematic numerical studies for the improvement of battery performance. With the rapid development of 3‐D imaging techniques, quantitative assessment of 3‐D microstructures from 2‐D image sections by stereological methods appears outmoded; however, in spite of the proliferation of tomographic imaging techniques, it remains significantly easier to obtain two‐dimensional (2‐D) data sets. In this study, stereological prediction and three‐dimensional (3‐D) analysis techniques for quantitative assessment of key geometric parameters for characterizing battery electrode microstructures are examined and compared. Lithium‐ion battery electrodes were imaged using synchrotron‐based X‐ray tomographic microscopy. For each electrode sample investigated, stereological analysis was performed on reconstructed 2‐D image sections generated from tomographic imaging, whereas direct 3‐D analysis was performed on reconstructed image volumes. The analysis showed that geometric parameter estimation using 2‐D image sections is bound to be associated with ambiguity and that volume‐based 3‐D characterization of nonconvex, irregular and interconnected particles can be used to more accurately quantify spatially‐dependent parameters, such as tortuosity and pore‐phase connectivity.     

Private Enterprise in Eclipse? A Reassessment of British Housing Policy in the 1940s

Conventional analyses of housing policy in most European countries treat the 1940s as a decade when private enterprise was eclipsed by social housing programmes. As a result, private enterprise is also eclipsed in most accounts of housing and housing policy in the early post-war period. This paper draws on the British experience to show that if the policy narrative is traced from wartime plans rather than from post-war action, and if the question of who actually built post-war social housing is raised, then a different picture emerges. From the middle of 1942 British civil servants and ministers were engaged in detailed planning for post-war housing, in both the short and long term. Private enterprise was assumed to have a major role to play in the long term, and a supporting role in the transitional period. In practice the post-war Labour Government relied on local authorities as housing developers, who themselves relied on private contractors to build the houses. The eclipse of private enterprise was, therefore, more apparent than real.     

MEASUREMENT OF PEA TENDERNESS IV. Development and Evaluation of the Test Cell*

A wire extrusion cell was developed to measure pea tenderness. The area of the cell and the wire grid dimensions affected the readings. The maximum force was linearly related to the total length of the shearing wires and the open area of the grid. Cells could be made interchangeable in testing unsieved peas within 1% or better using economic manufacturing tolerances. Sample temperature, time after harvest and damage to the wires of the test cell had negligible effects on the readings. The effect of variation in compression speed was small and erratic. Sample weight, however, had a marked effect on the results.