ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb02467.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYA surveying optical diffractometer is described which provides an efficient means of obtaining high quality optical diffraction patterns of particularly suitable specimens from electron micrographs.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb02468.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYThe degree of accumulation of neuronal lipofuscin in the human brain can indicate the age of some neurones, may be correlated with certain disease processes and can be affected by drugs. The estimation of the volume of neuronal lipofuscin has usually employed relatively unreliable methods such as counting techniques or visual ratings, while the present paper describes and illustrates a method for measuring the intensity of the autofluorescence derived from neuronal lipofuscin. The relationship between autofluorescence intensity and amount of lipofuscin is discussed.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb02469.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYSolid standards with reliable reflectance references are of fundamental importance for exact measurements of specular reflectances of microscopical objects. The liquid surface is the utopia of surfaces sought as reference for the calibration of solid standards. However, there are difficulties in setting the measuring equipment and adjusting the liquid surface for the comparison with the solid body. In this paper, the ‘liquid’ method is described clearly for microscopists to consi

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb02470.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYTwo mandibular condyles of a growing monkey (Macaca fascicularis) were used for developing and testing a morphometrical model system suitable for generating quantitative data about the structure of and the growth activities in the articulating surface layers. The animal received3H‐proline (1 mCi/kg body weight) 24 h and3H‐thymidine (0.5 mCi/kg body weight) 3 h prior to killing. Using standardized conditions, 1–2 μm thick histological sections were processed for autoradiography. The morphometrical analysis was carried out using light microscopy at two levels of magnification. Sampling of tissue fields was performed at twenty‐four (level I) and twelve (level II) different sites, respectively. These sites were distributed systematically in the anteroposterior and lateromedial dimension of the cartilaginous condylar covering. Using a multivariate analysis of variance, a parameter comparison revealed significant differences between single sampling sites in the anteroposterior as well as in the lateromedial direction, suggesting that the articulating condylar surface is inhomogeneous with respect to both structures and growth activities. The sampling mode eventually arrived at in this study was shown to be sufficient for the recording of gradients within the condylar surface layers. The model system presented permits simultaneous quantitative characterization of structure and growth activities such as mitotic cell division and extracellular matrix production of the condylar cartilage including the zone of its replacement

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb02471.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYWe have developed a temperature controlled specimen stage on the existing jet‐freezing apparatus, in order to quench samples from elevated temperatures up to 330 K. We have shown that the phase transition both from the liquid‐crystalline to solid phase for pure phosphatidylcholines and from hexagonal II to lamellar phase for phosphatidylethanolamine/4% egg phosphatidic acid is prevented. Moreover, cooling rates exceeding 10,000 K s—1were recorded indicative of ultra‐rapid freezing capacity. Cryoprotectants can be omitted, since phase separation due to ice crystal growth does no

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb02472.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYIon beam thinning of aluminium–lithium alloys under conventional conditions required to produce electron microscope thin foils is shown to induce significant microstructural changes, equivalent to heating the specimen in excess of ∼40

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb02473.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYCombined scanning transmission electron microscopy (STEM) and X‐ray microanalysis have been used to detect the equilibrium segregation of bismuth to grain boundaries in copper. Quantification of the X‐ray data gives grain boundary bismuth concentrations close to those reported previously by Auger electron spectroscopy (AES). Samples tempered at low temperatures (773,873 K) had detectable bismuth concentrations at more boundaries than those samples tempered at high temperature (1073 K). There is evidence that the degree of segregation varies strongly from boundary to bound

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb02474.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYThe use of propane/isopentane mixtures as cooling media is proposed since they remain fluid at liquid nitrogen temperature. The attainable cooling rates are virtually identical to those obtained in liquid propane.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb02475.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYFactors liable to limit the validity of liquid sample analysis by electron microprobe are investigated. For lyophilized samples composed of large 2–6 μm crystals, linear calibration curves may still be obtained for Na, Mg, P, Cl, K and Ca by raising the accelerating voltage to 18 kV, provided the X‐ray take‐off angle of the electron microprobe is 40°. Routinely prepared lyophilized samples are composed of discrete crystals. Their size is reproducible, depending on the composition of the dried deposit, and ranges from 0.1 to 0.5 μm for deposits mainly composed of NaCl. Within this range, the proportionality of X‐ray intensity to concentration is not affected by particle size. The concentration range for which X‐ray intensities remain proportional to concentrations is experimentally determined for the six elements above as a function of sample mass thickness and accelerating voltage. For certain elements, the proportionality constant is shown to vary with the composition of the solution. As regards chlorine concentration determinations, analysis of plasma ultrafiltrate and recovery experiments suggest that the proportionality constant is definitely 10% higher for this ultrafiltrate than for standa

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb02476.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY