摘要:

SYNOPSISThe behaviour of microscopic collagen fibres under pressures applied radially to the bundles has shown that distinct morphological differences exist between them. Four types have been observed and defined by their structural differences and their related optical, chemical, and mechanical properties. Resistance to acid swelling, birefringence, and the elastic and plastic deformation under pressure all vary with the structure, and it is suggested that in these variant types the molecular chains may be in a state of “closer packing.”The variant types have been observed in a wide range of tissues from many species but there are marked variations between the proportions present in specimens from the same species. There is some evidence that the proportion of variant types is associated with the age of the specimen.In addition two other fibrous types have been observed, which may be of a keratinous nature but which are always closely associated with normal collagen bundles. These possess jointed or segmented structures which under extreme pressures exhibit complex fibrillar structures which appear to run from one joint to another. The presence of these in otherwise normal tissue suggests that their origin may involve several orders of control over the fibrogenesis to produce the alternating parallel and swollen secti

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1957.tb02013.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

SYNOPSISA description is given of investigations on size distribution of normal human spermatozoa. The size distribution curves found are not Gaussian but logarithmic, and can accurately be described by the equation:whereN= number of sperm heads with lengthL, Nmax= number of sperm heads having the most frequently occurring lengthLme= base of Napierian logarithmsk= a constant.A similar distribution was found for the length and the breadth of the nucleus.In addition, empirical formulae for calculating the area of the optical longitudinal section of the sperm head and its volume were derived from model experiments. The area of the section can be calculated with fair accuracy for practical purposes from the equation:whereL= length andBmaxis the breadth at the broadest part. The empirical equation for the volumeVis:whered= thickness. Using this equation, the volume of a sperm head of the most probable dimensionsL= 4.4 μ,Bmax= 3.2 μ andd= 2.0 μ is found to be 6.4 μ3± 0.4.Methods for calculating the volume of the middle‐piece, the tail, and the tail‐end are also discussed.Some estimates of weight, based on measurements with the Baker interference microscope, a

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1957.tb02014.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

SYNOPSISMuds collected by immersing bakelite panels in four West African harbours were examined for diatoms. The flora was found to consist of 194 species, 13 being new to science.

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1957.tb02015.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1957.tb02016.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1957.tb02017.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

Book reviewed in this article:Fundamentals of the Beating Process.—H. W. Emerton.“Brushmaking Materials”.—F. A. Kidd. British Brush Manufacturers' Research Association, LondonFibre Microscopy.—J. L. Stoves.X‐ray Crystal Structure.—D. Machlan Jun.Microscopium.—Maria Rooseboom. (Rijksmuseum voor de Geschiedenis der Natuurweten‐schappen, 1A, Steenstraat, Leyden.)Electron Microscopy.—Proceedings of the Stockholm Conference, September, 1956.Mikroskopische Instrumente und Hilfsgerä

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1957.tb02018.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY