Scanning electron microscopic analysis of pancreatic tissue in alcoholic and tropical chronic pancreatitis.

INTRODUCTION: Chronic Pancreatitis (CP) is a heterogenous disease with alcoholic chronic pancreatitis (ACP) dominating in the West, and idiopathic or tropical chronic pancreatitis (TCP) in the tropics. The aim of this study is to assess the feasibility of using a scanning electron microscope (SEM) to analyze the ultra-structural changes in alcoholic and tropical subtypes of CP. METHODS: Chronic pancreatitis tissue samples were taken from the biopsy samples of 16 patients (seven ACP and nine TCP) who underwent drainage procedures for CP. These samples were subjected to SEM analysis and findings of normal pancreas were compared with those of CP for appreciating differences in their architectural changes. RESULTS: Normal architecture of pancreas could be observed as lobules of parenchyma, ductal system and definite loci of Islets of Langerhans (IOL). CP samples showed loss of architecture in the form of severe fibrosis and calcifications. In ACP, the fibrosis was predominantly seen towards the periphery of the gland sparing the periductal areas. These fibres were strangulating and damaging the parenchyma. Crystals were seen over these fibres. In TCP, fibrosis was moderate and uniform throughout the parenchyma. Moreover the crystals were larger and intraluminal. Total fatty replacement of parenchyma was a striking feature in TCP, seen exclusively in diabetics with gross atrophy of IOL. CONCLUSION: SEM gives the real-life pictures of fibrosis, fatty change, ductal changes, calcifications and thus the actual extent of damage in CP better than the ordinary light microscopy.

Influence of cation substitution and activator site exchange on the photoluminescence properties of Eu3+-doped quaternary pyrochlore oxides.

Stannate-based pyrochlore-type red phosphors CaGd(1-x)SnNbO7:xEu(3+), Ca(1-y)Sr(y)Gd(1-x)SnNbO7:xEu(3+), and Ca(0.8-x)Sr0.2GdSnNbO(7+δ): xEu(3+) were prepared via conventional solid-state method. Influence of cation substitution and activator site control on the photoluminescence properties of these phosphors are elucidated using powder X-ray diffraction, Rietveld analysis, Raman spectrum analysis, and photoluminescence excitation and emission spectra. The Eu(3+) luminescence in quaternary pyrochlore lattice exemplifies as a very good structural probe for the detection of short-range disorder in the lattice, which otherwise is not detected by normal powder X-ray diffraction technique. The Eu(3+) emission due to magnetic dipole transition ((5)D0-(7)F1 MD) is modified with the increase in europium concentration in the quaternary pyrochlore red phosphors. (5)D0-(7)F1 MD transition splitting is not observable for low Eu(3+) doping because of the short-range disorder in the pyrochlore lattice. Appearance of narrow peaks in Raman spectra confirms that short-range disorder in the crystal lattice disappears with progressive europium doping. By using Sr as a network modifier ion in place of Ca we were able to increase the f-f transition intensities and europium quenching concentration. The influence of effective positive charge of the central Eu(3+) ions when it replaces a metal ion having lower oxidation state such as Ca(2+) was also investigated. The relative intensities of A1g (∼500 cm(-1)) and F2g (∼330 cm(-1)) Raman vibrational modes get inverted when Eu(3+) ions replaces Ca(2+) ions instead of Gd(3+) as trivalent europium ions can attract the electron cloud of oxygen ions strongly in comparison with divalent calcium ions. The influence of positive charge effect of Eu(3+) in Ca0.7Sr0.2GdSnNbO7+δ:0.1Eu(3+) phosphor is greatly strengthened the charge transfer band and (7)F0-(5)L6 transition intensities than that of the Ca0.8Sr0.2Gd0.9SnNbO7:0.1Eu(3+) phosphor. Our results suggest that the photoluminescence properties can be enhanced by simple compositional adjustments in the quaternary pyrochlore-type red phosphors.

Role of bond strength on the lattice thermal expansion and oxide ion conductivity in quaternary pyrochlore solid solutions.

Quaternary pyrochlore-type solid solutions, CaGdZrNb(1-x)Ta(x)O(7) (x = 0, 0.2, 0.4, 0.6, 0.8, 1), were prepared by a high-temperature ceramic route. The pyrochlore phases of the compounds were confirmed by powder X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscopy. The crystallographic parameters of the pyrochlore compounds were accurately determined by Rietveld analysis of the powder XRD data. The isovalent substitution of Ta in place of Nb at the B site can reveal the effect of chemical bonding on lattice thermal expansion and oxide ion conductivity because both Nb and Ta have the same ionic radius (0.64 Å). Lattice thermal expansion coefficients of the samples were calculated from high-temperature XRD measurements, and it was found that the thermal expansion coefficient decreases with substitution of Ta. Oxide ion conductivity measured by a two-probe method also shows the same trend with substitution of Ta, and this can be attributed to the high bond strength of the Ta-O bond compared to that of the Nb-O bond. Microstructural characterization using scanning electron microscopy proves that the size of the grains has a small effect on the oxide ion conductivity. Our studies established the role of chemical bonding in deciding the conductivity of pyrochlore oxides and confirmed that the 48f-48f mechanism of oxide ion conduction is dominant in pyrochlore oxides.

Indium doped ZnO films prepared by RF magnetron sputtering: effect of substrate temperature on the strain-induced band gap.

Indium doped zinc oxide (InZnO) thin films were deposited onto corning glass substrates by RF magnetron sputtering. The dependence of crystal structure, surface morphology, optical properties and electrical conductivity on substrate temperature was investigated using XRD, AFM, UV-vis Spectrophotometer, Fluorescence Spectrophotometer and four-point probe. The films were prepared at different substrate temperatures viz, room temperature (RT), 473 K and 673 K at RF power 200 W. All the films showed preferred orientation along (002) direction. Crystallite size increased from 14 to 19 nm as the substrate temperature was increased to 473 K. With increase in substrate temperature the crystallites did not show any further growth. AFM analysis showed that the rms roughness value decreased from 60 nm to 23 nm when the substrate temperature was increased to 673 K. Optical measurements revealed maximum band gap and minimum refractive index for the film prepared at 473 K. A strong correlation between the band gap variation and the strain developed at different substrate temperatures is established.

Role of scanning electron microscopy in identifying drugs used in medical practice.

Several plant preparations are administered for treatment of stone disease without scientific basis. This paper presents the results of in vitro and animal experimental studies using scanning electron microscopy (SEM) in the identification of the therapeutic properties of trial drugs in medicine. In the first set of the study, urinary crystals namely calcium oxalate monohydrate and calcium oxalate dehydrate were grown in six sets of Hane's tubes in silica gel medium. Trial drugs namely scoparia dulcis Lynn, musa sapiens and dolicos biflorus were incorporated in the gel medium to identify the dopant effect of the trial drugs on the size and extent of crystal column growth. The changes in morphology of crystals were studied using SEM. In the second set, six male Wistar rats each were calculogenised by administering sodium oxalate and ethylene glycol and diabetised using streptozotocin. The SEM changes of calculogenisation were studied. The rats were administered trial drugs before calculogenisation or after. The kidneys of the rats studied under the scanning electron microscope showed changes in tissue morphology and crystal deposition produced by calculogenisation and alterations produced by addition of trial drugs. The trial drugs produced changes in the pattern of crystal growth and in the crystal morphology of both calcium oxalate monohydrate and calcium oxalate dihydrate grown in vitro. Elemental distribution analysis showed that the crystal purity was not altered by the trial drugs. Scoparia dulcis Lynn was found to be the most effective anticalculogenic agent. Musa sapiens and dolicos biflorus were found to have no significant effect in inhibiting crystal growth. The kidneys of rats on calculogenisation showed different grades of crystals in the glomerulus and interstitial tissues, extrusion of the crystals into the tubular lumen, collodisation and tissue inflammatory cell infiltration. Scoparia dulcis Lynn exhibited maximum protector effect against the changes of calculogenisation. Musa sapiens and dolicos biflorus had only minimal effect in preventing crystal deposition, inflammatory cell infiltration and other changes of calculogenisation. SEM was found to be effective in assessing the effect of drugs on crystal growth morphology and tissue histology.

Ultrastructural study of laminated urinary stone.

Several modalities of stone analysis are utilised in different laboratories. However, the treating clinician finds it hard to assess the initiation and progression of stone formation. The pathogenesis of calculogenesis still remains a mystery. The purpose of this paper is to assess the pathological mechanisms of stone nucleation and growth by observing the ultra microscopic morphology of the different layers of laminated stones; 130 fragments from 28 randomly selected laminated stones of more than 10-mm diameter were analysed. Wet chemical analysis of the stones was performed. Surface and cross-sectional morphology of the entire stones and the individual fragments was assessed using optical microscopy and images were recorded using ordinary camera. They were further analysed using FTIR for confirmation. By morphological analysis, whewellite, weddellite, uric acid, and phosphate were the main minerals identified. Mixtures of these minerals were also found. Concentric lamination, radial striation, frond formation, and amorphous pattern were the main cross-sectional morphologies obtained. The calculi analysed had differences in their outer and inner portions. This was more pronounced in stones containing predominantly whewellite and uric acid. Whewellite was the outer component in most mixed stones. Uric acid was more in the inner layers of mixed stones than the surface.

Problem in analyzing cystine stones using FTIR spectroscopy.

Cystine stones are produced by an inherited disorder of the transport of amino acid cystine that results in excess of cystine in the urine (cystinuria). Cystine calculi in urinary tract present a significant problem in patients. We have recorded that cystine calculi are very uncommon in our region. Cystine crystals are unusually identified in the urinary deposits. The problem of recognizing cystine by FTIR as a component in mixture of stones is significant. The problem is compounded by the similarity of wavelengths of cystine with that of whewellite and uric acid. The objective of this paper is to elucidate the problems of identifying cystine in stone analysis and identifying a solution to get over this deficiency. Out of 1,300 urinary stones analysed by ordinary wet chemical methods and infrared spectroscopy, 30 stone samples, which were reported to have cystine peaks in significant numbers, were selected. These samples were powdered, mixed with potassium bromide, pelletized and taken up for FTIR analysis. The wavelength patterns were scrutinized by comparing with the peaks obtained by the reference standards of cystine. Spectra were also obtained from pure cystine. Comparison of spectra with those of whewellite and uric acid was performed. Then the samples were taken for Scanning electron microscopy with elemental distribution analysis X-ray (SEM-EDAX). The samples were made conductive by gold sputtering and were fed into JEOL JSM 35 C SEM machine. Morphology was recorded by taking photographs. Further elemental distribution analysis (EDAX) was carried out to identify the elemental composition. Of the 30 samples taken up for FTIR analysis, all showed spectra identifiable with the reference peaks for cystine. However, when these peaks were compared with those of whewellite and uric acid, all the stone samples showed duplication of peaks for whewellite and uric acid and whewellite. The pure cystine spectra showed identifiable peaks are in the range of 3026, 1618.28, 1485, 846.75 cm(-1), etc. (from the standard spectrum of pure cystine). All the analysis findings were correlated with EDAX findings. On doing EDAX, we could separately find out the components present in a mixture. Three stones contained elemental pattern to fit with those of cystine. Even though it is difficult to find out the presence of cystine molecule in FTIR, it is possible to recognize it through EDAX and will be possible to confirm the presence of cystine in mixed urinary stones.

Optical microscopy versus scanning electron microscopy in urolithiasis.

Stone analysis is incompletely done in many clinical centers. Identification of the stone component is essential for deciding future prophylaxis. X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy (SEM) still remains a distant dream for routine hospital work. It is in this context that optical microscopy is suggested as an alternate procedure. The objective of this article was to assess the utility of an optical microscope which gives magnification of up to 40x and gives clear picture of the surface of the stones. In order to authenticate the morphological analysis of urinary stones, SEM and elemental distribution analysis were performed. A total of 250 urinary stones of different compositions were collected from stone clinic, photographed, observed under an optical microscope, and optical photographs were taken at different angles. Twenty-five representative samples among these were gold sputtered to make them conductive and were fed into the SEM machine. Photographs of the samples were taken at different angles at magnifications up to 4,000. Elemental distribution analysis (EDAX) was done to confirm the composition. The observations of the two studies were compared. The different appearances of the stones under optical illuminated microscopy were mostly standardized appearances, namely bosselations of pure whewellite, spiculations of weddellite, bright yellow colored appearance of uric acid, and dirty white amorphous appearance of phosphates. SEM and EDAX gave clearer pictures and gave added confirmation of the stone composition. From the references thus obtained, it was possible to confirm the composition by studying the optical microscopic pictures. Higher magnification capacity of the SEM and the EDAX patterns are useful to give reference support for performing optical microscopy work. After standardization, routine analysis can be performed with optical microscopy. The advantage of the optical microscope is that, it is easy to use and samples can be analyzed in natural color.

Elemental distribution analysis of urinary crystals.

Various crystals are seen in human urine. Some of them, particularly calcium oxalate dihydrate, are seen normally. Pathological crystals indicate crystal formation initiating urinary stones. Unfortunately, many of the relevant crystals are not recognized in light microscopic analysis of the urinary deposit performed in most of the clinical laboratories. Many crystals are not clearly identifiable under the ordinary light microscopy. The objective of the present study was to perform scanning electron microscopic (SEM) assessment of various urinary deposits and confirm the identity by elemental distribution analysis (EDAX). 50 samples of urinary deposits were collected from urinary stone clinic. Deposits containing significant crystalluria (more than 10 per HPF) were collected under liquid paraffin in special containers and taken up for SEM studies. The deposited crystals were retrieved with appropriate Pasteur pipettes, and placed on micropore filter paper discs. The fluid was absorbed by thicker layers of filter paper underneath and discs were fixed to brass studs. They were then gold sputtered to 100 A and examined under SEM (Jeol JSM 35C microscope). When crystals were seen, their morphology was recorded by taking photographs at different angles. At appropriate magnification, EDAX probe was pointed to the crystals under study and the wave patterns analyzed. Components of the crystals were recognized by utilizing the data. All the samples analyzed contained significant number of crystals. All samples contained more than one type of crystal. The commonest crystals encountered included calcium oxalate monohydrate (whewellite 22%), calcium oxalate dihydrate (weddellite 32%), uric acid (10%), calcium phosphates, namely, apatite (4%), brushite (6%), struvite (6%) and octocalcium phosphate (2%). The morphological appearances of urinary crystals described were correlated with the wavelengths obtained through elemental distribution analysis. Various urinary crystals that are not reported under light microscopy could be recognized by SEM-EDAX combination. EDAX is a significant tool for recognizing unknown crystals not identified by ordinary light microscopy or SEM alone.

EDAX versus FTIR in mixed stones.

Mixed stones form a significant number of all urinary stones. Accurate analysis of individual areas of stones is fraught with uncertainties. Scanning electron microscopy with elemental distribution analysis (SEM-EDAX) is a very important tool in assessing stone composition. The objective of this paper is to project the role of the combination of Fourier transform infrared (FTIR) spectroscopy and SEM-EDAX combination in achieving a total understanding of mixed stone morphology. Ten mixed urinary stones were washed and dried and the composition recognized by analysis of FTIR spectra by comparing with the spectra of pure components. Spectra for different layers were obtained. Then the stone samples were further studied by SEM-EDAX analysis. The findings of FTIR were correlated with SEM-EDAX and detailed data generated. Using SEM-EDAX, the spatial distribution of major and trace elements were studied to understand their initiation and formation. As much as 80% of the stones studied were mixtures of calcium oxalate monohydrate (whewellite) and calcium phosphate (hydroxyapatite) in various proportions. Quantitative evaluation of components was achieved through FTIR and SEM-EDAX analysis. It was possible to get an idea about the spatial distribution of molecules using SEM analysis. The composition of different areas was identified using EDAX. Analyzing with EDAX, it was possible to obtain the percentage of different elements present in a single sample. The study concludes that the most common mixed stone encountered in the study is a mixture of calcium oxalate monohydrate and calcium phosphate in a definite proportion. The combination identified not only the molecular species present in the calculus, but also the crystalline forms within chemical constituents. Using EDAX, the amount of calcium, phosphorus, oxygen and carbon present in the stone sample could be well understood.

Influence of disorder-to-order transition on lattice thermal expansion and oxide ion conductivity in (Ca(x)Gd(1-x))(2)(Zr(1-x)M(x))2O7 pyrochlore solid solutions.

The effect of simultaneous substitutions of Ca at A site and Nb or Ta at B site in pyrochlore-type solid solutions: (Ca(x)Gd(1-x))(2)(Zr(1-x)M(x))(2)O(7) (x = 0.1, 0.2, 0.3, 0.4, 0.5 and M = Nb or Ta) were studied by powder X-ray diffraction (XRD), FT NIR Raman spectroscopic techniques and transmission electron microscopy. The solid solutions were prepared by the conventional high-temperature ceramic route. The XRD results and Rietveld analysis revealed that the defect fluorite structure of Gd(2)Zr(2)O(7) progressively changed to a more ordered pyrochlore phase by simultaneous substitutions at A and B sites. Raman spectroscopy reveals the progressive ordering in the anion sublattice with simultaneous doping. High-resolution images and selected-area electron diffraction patterns obtained from TEM confirms the XRD and Raman spectroscopic results. High-temperature XRD studies show that the lattice expansion coefficient in these pyrochlore oxides is of the order of 10(-6) K(-1). Lattice thermal expansion coefficient increases with increase of disorder in pyrochlore oxides, and hence the variation of thermal expansion coefficient with composition is also a good indicator of disordering in pyrochlore-type oxides. The ionic conducting properties of the samples were characterised by impedance spectroscopy, and it was found that Nb-doped compositions show a considerable change in conductivity near the phase boundary of disordered pyrochlore and defect fluorite phases.