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At least 1,387 records · Page 77Linked to original sources
PubMed1986

[Asbestosis of the bladder neck and prostate. Reflections on 2 cases].

Ingested asbestos is mainly excreted in the urine. Marked impregnation of bladder neck in a patient working in an asbestos factory was diagnosed initially as a tuberculosis lesion on the granulomatous histologic appearance. Asbestos fibers were counted by electron microscopy. This appears to be the first case of this type reported and possible causal relations and histopathologic findings are discussed. Also reported is a patient with prostatic cancer, and chronic pulmonary asbestosis, treated by adenomectomy using an upper approach 15 years previously. The cancer was of the prostate transitional cell type. A causal relation could not be proved but other such cases should be investigated, to determine a possible link between the lesion and industrial fibers.

Adult↗
PubMed1979

X-ray microanalytical studies on native myofibrils and mitochondria isolated by microdissection from honey-bee flight muscle.

The distribution of elements was studied by means of energy dispersive X ray microanalysis in the honey-bee flight muscle. Semi-quantitative analysis of bulk muscle specimen, isolated mitochondria and isolated myofibrils either in resting or stretched state was performed. High K peak was observed in the spectra of bulk muscle specimen resembling the spectra of myofibrils and high P peak resembling the spectra of mitochondria. In the myofibrils no substantial difference was found between the spectra of A bands and Z lines, but they contained much higher K peak than the spectra of I bands.

Animals↗
PubMed1980

Progress in electron energy loss analysis for biological specimens.

Recent work, both experimental and theoretical has clarified the range of applicability, optimum conditions of operation and limits of detection of the EELS technique. Its chief use is for microanalysis of light elements (Z < 10). For heavier elements, however, it also has an important advantage over X-ray methods in requiring lower electron exposure of the specimen for given signal strength.

Electron Probe Microanalysis↗
PubMed1981

[Cast fractures of dental Ni-Cr alloys (author's transl)].

Cast fractures of Ni-Cr alloys were investigated by means of scanning electron microscopy, energy dispersive X-ray spectrometry, electron-probe microanalysis, density measurements, setting and thermal expansion measurements and compressive tests. Three-Ni-Cr alloys for crowns and bridges were cast in spiral configurations by an argon-arc pressured type or an induction argon-pressured type-casting machine. The amount of cast fracture increase with an increase in cast temperature, but not with an increase of holding time at cast temperature. Ni-Cr alloys have more cast fractures in a phosphate-bonded investment than in a gypsum-bonded cristobalite investment. Fracture surfaces have an exposed dendrite structure, indicating the presence of cast porosity. The trigger of cast crack can be a cast porosity and the propagation of crack to fracture may be mainly due to the strength of investments.

Chromium Alloys↗
PubMed1981

Calcium oxalate crystal growth in human urinary stones.

Calcium oxalate stones are very common and increasing. Crystal growth is no less important than the crystal nucleation in the pathogenesis of stone formation. The crystal growth was studied in human calcium oxalate stones by a combined electron microscopy and x-ray diffraction. The main mode of weddellite growth was interpenetration twinning of tetrahedral bipyramids. Bipyramids may form as initial crystal seeds, develop from anhedral crystals (crystals which lack flat symmetric faces) of spherular or mulberry shape, develop on the surface of preformed bipyramids by spiral dislocation mechanisms, or develop on whewellite crystal by heterogeneous nucleation and epitaxy. Heterogeneous nucleations of whewellite on weddellite, and calcium apatite on whewellite were also observed. Whewellite grew mainly by parallel twinning. Interpenetration twinning was exceptional. Transformation of anhedral to euhedral (completely bounded by flat faces that are set ar fixed angles to one another) whewellite occurred by parallel fissurations followed by brick wall like stacking of the crystals, while euhedral transformation of weddellite occurred by protrusion of bipyramids frm anhedral crystal surface. Occasionally, an evidence of crystal dissolution was noted. Although an aggregation of crystals is believed to play a pivotal role in stone nidus formation, growth in size of the formed crystals, and twinning and epitactic crystal intergrowth apparently play a significant role in the obstructive urinary stone formation.

Calcium Oxalate↗
PubMed1995

Backscattered electron imaging and energy-dispersive X-ray microanalysis studies of evidence for calcium salt heterogeneity in fifteen gallstones from an elderly human.

We examined 15 variably-sized gallstones, taken from an elderly male, by backscattered electron imaging and energy-dispersive X-ray microanalysis to learn the structural and distribution patterns of gallstone calcium (Ca-) salts. Of the 13 cholesterol-rich stones, nine stones had peripheral concentric layers of Ca-carbonate, whereas 2 stones had peripheral layers of Ca-phosphate. No Ca-salts were detected from 2 cholesterol-rich stones. The 2 stones containing Ca-phosphate had no Ca-salt cores, whereas the stones containing Ca-carbonate were separated into 3 different types: two stones with a Ca-carbonate core, four stones with several Ca-bilirubinate cores of glass-like structure, and 3 stones lacking Ca-salt cores. A closer view of the Ca-salt layers, which may be occasionally coexistent with Ca-bilirubinate, mainly showed either laminate deposits or numerous globules with a few laminae. Of the 2 cholesterol-poor stones, one had dispersed particles mainly of Ca-phosphate, and the other had loosely dispersed particles with small amounts of Ca-phosphate, bilirubinate, and/or palmitate. Some relationship between the size and Ca-salt species of these gallstones was suggested. Gallstones collected from the same individual showed a considerable heterogeneity of Ca-salts.

Aged↗
PubMed1995

The use of grommets for flexible hinge toe implants. A case report.

The postmortem examination of bilateral first metatarsophalangeal flexible hinge toe implants in a 66-year-old woman with rheumatoid arthritis is reported. The prosthesis had been inserted with grommets in 1 joint and without grommets in the other 2.5 years before her death. The implants were removed, and the bone/implant interfaces were examined microscopically by hematoxylin eosin stains and an electron probe microanalyzer. Surfaces of the implants were examined by scanning electron microscopy. Silicone particles within the fibrous tissue at the bone/implant interface, and a tear and significant scuffing of the implant surface, were detected in the joint without grommets. Such changes were not detected in the joint with grommets. These findings suggest that grommets may improve implant durability and preventing silicone synovitis.

Aged↗
PubMed1994

Heterogeneous Mg-containing hydroxyapatites.

Two different Mg-containing hydroxyapatites, H-MgAp and Mg-HAp, were synthesized at 80 degrees C and pH 7.4. For H-MgAp, the calcium solution was supplied in the first half of the synthesis period and the calcium solution containing magnesium was supplied in the second half. For Mg-HAp, the order of supply was reversed. The X-ray diffraction patterns of H-MgAp and Mg-HAp differed slightly from each other. The (002) reflection of both patterns shifted towards a higher angle. The chemical compositions, especially the Mg contents, of the two apatites were almost the same as each other; and the Mg contents were half of that of homogeneous MgHAp synthesized with continuous supply of Mg at the same concentration. However, their crystal shapes were quite different, with H-MgAp appearing plate-like and Mg-HAp needlelike. In a solubility experiment, Mg-HAp was more soluble than H-MgAp. These results suggest that two different heterogeneous Mg-containing hydroxyapatites may be formed: hydroxyapatite covered with Mg-containing hydroxyapatite, and Mg-containing hydroxyapatite covered with hydroxyapatite.

Crystallography, X-Ray↗
PubMedDate not supplied

[Indoor pollution from airborne glass fibers in biomedical research laboratories].

It is known that the presence of fibers in indoor environment is able to lead to irritative symptoms of skin and mucous membranes. Such troubles have been repeatedly claimed by workers in biomedical research laboratories of our University. For this reason, an investigation for the evaluation of the risk and for propose preventional solutions has been performed (also for absolve fully to D.Lgs. 626/94). On account of the environmental investigations has been revealed the presence of rock wool fibers-included in a water lime matrix-sprayed in big quantity on the ceilings. Therefore, the phases and the methods followed for the analysis of the risks are showed together with evaluations in order to the preventional interventions, also on the basis of what has been established by the lawgiver.

Air Pollution, Indoor↗
PubMed1998

Stereo-4-D reconstruction and animation from living fluorescent specimens.

We present a novel approach to the viewing and analysis of 4-dimensional (4-D) data sets recorded from live fluorescent samples. With stereo-4-D reconstructions, the observer manipulates a rotatable projection of the full 3-dimensional (3-D) specimen while simultaneously controlling animation of the recording forward or backward in time. The result is a unique lifelike perspective on the development of an entire living subject. Here, we apply this technique to the observation of the cell membranes of developing Caenorhabditis elegans. Embryos labeled with the vital plasma membrane probe FM 4-64 were imaged by multiphoton laser scanning fluorescence microscopy, yielding 4-D data sets of entire embryos over several hours of development. Stereo 4-D and standard focal-plane 4-D viewing of these novel time-lapse recordings provide the observer with detail at both the subcellular and whole-animal level from a single data set and produce a unique record of the lineage, cell shape changes, cell contacts and morphogenetic dynamics that make up embryogenesis. The procedures by which stereo-4-D reconstructions are created and viewed rely on public domain software running on a personal computer and should therefore be accessible by a general audience. Data output utilizes the versatile and well-supported QuickTime animation format. Additional features allow for stereo-4-D reconstruction of isolated 3-D volumes of interest from within the larger specimen.

Animals↗
PubMed2001

Non-optical tip-sample distance control method for scanning near-field optical microscopy using a piezoresistive micro cantilever.

A piezoresistive micro cantilever is applied to monitor the displacement of an optical fibre probe and to control tip-sample distance. The piezoresistive cantilever was originally made for a self-sensitive atomic force microscopy (AFM) probe and has dimensions of 400 microm length, 50 microm width and 5 microm thickness with a resistive strain sensor at the bottom of the cantilever. We attach the piezoresistive cantilever tip to the upper side of a vibrating bent optical fibre probe and monitor the resistance change amplitude of the strain sensor caused by the optical fibre displacement. By using this resistance change to control the tip-sample distance, the two-cantilever system successfully provides topographic and near-field optical images of standard samples in a scanning near-field optical microscopy (SNOM)/AFM system. A resonant characteristic of the two-cantilever system is also simulated using a mechanical model, and the results of simulation correspond to the experimental results of resonance characteristics.

Journal Article↗
PubMed2005

Physical and mechanical characterization and the influence of cyclic loading on the behaviour of nickel-titanium wires employed in the manufacture of rotary endodontic instruments.

AIM: To analyse the influence of cyclic loading on the mechanical behaviour of nickel-titanium (NiTi) wires employed in the manufacture of ProFile rotary endodontic instruments. METHODOLOGY: Nickel-titanium wires, 1.2 mm in diameter, taken from the production line of ProFile rotary endodontic instruments before the final machining step, were tensile-tested to rupture in the as-received condition and after 100 load-unload cycles in the superelastic plateau (4% elongation). The wires were characterized by X-ray energy-dispersive spectroscopy, X-ray diffraction and by differential scanning calorimetry and compared with new size 30, .06 taper ProFile instruments. The fracture surfaces of the wires were observed by scanning electron microscopy. RESULTS: The mechanical properties of the as-received wires, their chemical composition, the phases present and their transformation temperatures were consistent with their final application. Only small changes, which decreased after the first few cycles, took place in the mechanical properties of the cycled wires. The stress at maximum load and the plastic strain at breakage remained the same, while the critical stress for inducing the superelastic behaviour, which is related to the restoring force of the endodontic instruments, decreased by approximately 27%. CONCLUSIONS: The mechanical behaviour of the NiTi wires was modified slightly by cyclic tensile loading in the superelastic plateau. As the changes tended towards stabilization, the clinical use of rotary NiTi ProFile instruments does not compromise their superelastic properties until they fracture by fatigue or torsional overload, or are otherwise discarded.

Calorimetry, Differential Scanning↗