The x-ray microanalysis of the mucosa of the rat small intestine

A rat small intestine mucosa is shown to accumulate significant amount of potassium and chloride. There was found a correlation between the content of these chemical elements and glycoprotein compartmentalization in goblet cell secret, brush border of enterocytes and a mucus layer. In this connection a role of mucus glycoproteins in membrane digestion is discussed. For preparation of samples the cryotechniques of electron microscopy are used.     

An image processing system for digital chest X-ray images

This paper investigates the requirements for image processing of digital chest X-ray images. These images are conventionally recorded on film and are characterised by large size, wide dynamic range and high resolution. X-ray detection systems are now becoming available for capturing these images directly in photoelectronic-digital form. In this report, the hardware and software facilities required for handling these images are described. These facilities include high resolution digital image displays, programmable video look up tables, image stores for image capture and processing and a full range of software tools for image manipulation. Examples are given of the application of digital image processing techniques to this class of image.     

An image processing system for digital chest X-ray images

This paper investigates the requirements for image processing of digital chest X-ray images. These images are conventionally recorded on film and are characterised by large size, wide dynamic range and high resolution. X-ray detection systems are now becoming available for capturing these images directly in photoelectronic-digital form. In this report, the hardware and software facilities required for handling these images are described. These facilities include high resolution digital image displays, programmable video look up tables, image stores for image capture and processing and a full range of software tools for image manipulation. Examples are given of the application of digital image processing techniques to this class of image.     

Quantitative local x-ray spectral microanalysis of single erythrocytes

Quantitative x-ray microanalysis was used to study the content of sodium, potassium, phosphorus and chlorine in single peripheral red blood cells of man. The method for sample preparation described permits its successful use under clinical and field conditions.     

Light element analysis of individual bacteria by x-ray microanalysis

A method based on X-ray microanalysis (XRMA) with the transmission electron microscope for measurement of total amounts of elements in single microbial cells has been developed. All major elements in cells except hydrogen can be measured simultaneously. XRMA provided N/C ratios (means (plusmn) standard errors of the mean) for stationary-phase and growing Escherichia coli of 0.23 (plusmn) 0.01 and 0.30 (plusmn) 0.01, respectively, while CHN analysis gave values of 0.276 and 0.307, respectively, for samples from the same cultures. Analyses of free coccoliths from Emiliana huxleyi provided weight fractions close to those of CaCO(inf3): 0.35 (plusmn) 0.01, 0.15 (plusmn) 0.01, and 0.47 (plusmn) 0.01 for calcium, carbon, and oxygen, respectively. Calibration is based on monodisperse latex beads and on microdrops of defined compounds. Elements in particles in the size range from 5 fg to 500 pg are measured with a relative precision between 500 and 5,000 ppm, depending on size. As a single-cell method, XRMA avoids the shortcomings of commonly used fractionation techniques associated with bulk methods, which are based on centrifugation or filtration. On the basis of morphology and XRMA, particles may be classified more precisely into groups (e.g., biotic versus abiotic) than is possible by bulk methods. Single-cell elemental analysis may provide insight into topics like nutritional and energetic status, macromolecular composition, and (by multivariate statistics) community structure.     

Concentration of elements in mitotic chromatin as measured by x-ray microanalysis

Unfixed frozen-dried and uncoated tissue sections of the mouse duodenum were placed on carbon planchets and analyzed in a scanning electron microscope fitted with energy dispersive X-ray equipment. Computer analysis of the X-ray spectra allowed elemental microanalysis of the nucleus, cytoplasm, and mitotic chromatin regions in the cryptal and villus enterocytes. The peak to continuum ratio of S, Cl, K, and Ca were higher in mitotic chromatin than any of the other sites measured. The redistribution of Ca at mitosis is postulated to help explain both chromosome condensation and assembly of the mitotic spindle apparatus.     

Local x-ray spectral microanalysis in cell biology. The study of sections of hydrated biological tissues

Rules required for fixation of tissues are considered aimed for a further localization of chemical elements in these tissue by means of local X-ray microanalysis. In addition, difficulties involved in fixation of diffusible elements, such as potassium or sodium, are mentioned. Physical bases of preparation of hydrated tissues for X-ray analysis are discussed.     

Ion distribution in roots of barley seedlings measured by electron probe x-ray microanalysis

The distribution of ions, particularly K and Na, was studied in roots of barley seedlings grown on various ionic solutions. Analyses were made by means of electron probe x-ray microanalysis using frozen, fractured bulk specimens. By this technique, it was demonstrated that there can be variability in the ratio K/Na measured in the vacuoles of cortical cells, with this ratio often being lower in epidermal cells of the root than in the inner cortex. A sharp difference in the K/Na ratio was also found between cells of the endodermis and those of the adjacent cortex, and generally higher ratios of K/Na occurred in the stele than in the cortex. Estimation of the concentrations in the cytoplasm was at the limit of resolution of this technique, but it can be shown that the K/Na ratio in the cytoplasm was higher than that in the vacuole. In low salt roots, the K concentration in the cytoplasm was higher than that in the vacuoles. The results with the x-ray microprobe confirm other measurements based on flux analysis or analysis of small samples of the root.     

Renal sodium-potassium adenosine triphosphatase. Optical localization and x-ray microanalysis.

The distribution of sodium-potassium adenosine triposphatase (Na-K-ATPase) activity in kidney sections has been studied by a method based on the hydrolysis of p-nitrophenyl phosphate in alkaline medium containing dimethyl sulfoxide. The products at each stage in the reaction sequence have been subjected to electron probe microanalysis. The initial product was identified as a mixture of KMgPO4 and Mg(PO4)2, and sequential analysis demonstrated the linearity of conversion of this product to a visible form. In human, rabbit and rat kidneys the distribution of activity was found to be essentially identical, with highest levels located in thick ascending limbs and distal convoluted tubules. The initial reaction was completely potassium dependent and was inhibited by ouabain in concentrations reflecting the relative sensitivity of microsomal Na-K-ATPase in each species. Measurement of initial product phosphorus by means of the electron probe is presented as a practical technique for direct quantitation of Na-K-ATPase activity in identified tubule segments.     

Higuchi dimension of digital images

There exist several methods for calculating the fractal dimension of objects represented as 2D digital images. For example, Box counting, Minkowski dilation or Fourier analysis can be employed. However, there appear to be some limitations. It is not possible to calculate only the fractal dimension of an irregular region of interest in an image or to perform the calculations in a particular direction along a line on an arbitrary angle through the image. The calculations must be made for the whole image. In this paper, a new method to overcome these limitations is proposed. 2D images are appropriately prepared in order to apply 1D signal analyses, originally developed to investigate nonlinear time series. The Higuchi dimension of these 1D signals is calculated using Higuchi's algorithm, and it is shown that both regions of interests and directional dependencies can be evaluated independently of the whole picture. A thorough validation of the proposed technique and a comparison of the new method to the Fourier dimension, a common two dimensional method for digital images, are given. The main result is that Higuchi's algorithm allows a direction dependent as well as direction independent analysis. Actual values for the fractal dimensions are reliable and an effective treatment of regions of interests is possible. Moreover, the proposed method is not restricted to Higuchi's algorithm, as any 1D method of analysis, can be applied.     

Intracellular and luminal ion concentrations in sea turtle salt glands determined by x-ray microanalysis

Summary The lachrymal salt glands of hatchlings of the green sea turtle (Chelonia mydas) secrete a hyperosmotic (up to 2000 mosmol·kg^–1) NaCl solution. X-ray microanalysis of frozen-hydrated glands showed that during secretion intracellular Na⁺ concentration in the principal cells increased from 13 to 34 mmol·l^–1 of cell water, whilst Cl^– and K⁺ concentrations remained unchanged at 81 mmol·l^–1 and 160–174 mmol·l^–1, respectively. The high Cl^– concentration and the change in Na⁺ concentration are consistent with the prevailing paradigm for secretion by the structurally and functionally similar elasmobranch rectal gland. Concentrations of Na⁺, Cl^– and K⁺ in the lumina of secretory tubules of secreting (Na⁺ 122, Cl^– 167, K⁺ 38 mmol·l^–1) and non-secreting (Na⁺ 114, Cl^–1 174, K⁺ 44 mmol·l^–1) glands were similar and the fluid was calculated to be approximately isosmotic with blood. In the central canals Na⁺ and Cl^– concentrations were similar but K⁺ concentration was lower (11–15 mmol·l^–1). It is concluded that either a high transepithelial NaCl gradient in secretory tubules and central canals is very rapidly dissipated during the short time between gland excision and freezing, or that ductal modification of an initial isosmotic secretion occurs.     

数字信号处理在生物医学工程中的应用

数字信号处理技术一诞生就显示了强大的生命力,展现了极为广阔的应用前景.主要讨论数字信号处理技术中小波分析、人工神经网络、维格纳分布在生物医学工程中的应用,并对数字信号处理技术在生物医学工程中的应用前景进行了展望.     

Identification of a phosphorus-containing storage granule in the cyanobacterium plectonema boryanum by electron microscope x-ray microanalysis.

Transmission electron microscopy of cyanobacteria couple with X-ray microanalysis has confirmed that dense deposits within these cells are composed of phosphorous.