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This article presents the development of a process by which an impact experienced by a track-like structure can be reconstructed based on its vibration response. The process is essentially based on an inverse analysis technique, while a cepstral analysis technique is also used to improve waveform reconstructions. Firstly, a finite element (FE) model of a simple track structure was generated and calibrated to a real laboratory model to show that it was able to simulate impact events. The rail geometry was then replaced with a simple rectangular beam in order to allow simulation of a rolling wheel by means of a moving mean load. The simple beam geometry was necessary because the rail geometry carried an excessive computational cost when incorporating a moving mean load. This is a legitimate substitution because the inverse analysis technique is geometrically independent. It was found that the acceleration response of the track structure due to the dynamic impact was largely unaffected by the moving mean loading condition. It was also found that the inverse analysis technique shows potential for reconstructing input forces, but in some instances the reconstructed waveform has ambiguous peaks and excessive signal pollution around the force waveform. The cepstral analysis was then found to be useful in sufficiently ‘smoothing’ the transfer function spectrum such that an improved waveform reconstruction could be obtained. An error analysis showed that the regular transfer function as obtained by the inverse analysis technique when ‘smoothed’ by cepstral analysis gave a lower order of error. It was found that to provide sufficient coverage of a full crib of rail, three calibration points were required for the transfer function, with four accelerometers to pick up the track responses along the crib.

The ploidy distributions of rat liver nuclei isolated from normal and thyroidectomized rats were determined after conjugation with fluorochromes acridine orange and propidium iodide by rapid flow cytometry on the basis of their DNA content. Using this technique, we have confirmed the marked influence of thyroid status on the ploidy of rat liver nuclei as compared to euthyroid rats of the same age. No further development of tetraploid nuclei occurred from the time of thyroidectomy. However, administration of 1 mg T3/100 g BW to hypo-thyroid rats led within 6 days to ploidy patterns identical with those observed in euthyroid animals of the same age.

A simple and reliable method of determining the degree of dispersion of a cell suspension has been developed using the Perkin-Elmer Uni-Smear Spinner. Optimum conditions regarding rate and duration of spin, etc., were first ascertained using dispersed cell cultures including human cervical cancer cells as well as gynecologic samples. After spinning, single cells in suspension appeared as isolated cells on the slides. Cell aggregates, on the other hand, remained together. Therefore, the distribution of cells in various sized aggregates could be easily quantitated and the slides retained for future review. This method was used to evaluate the dispersing effects of trypsin, ethylenediaminetetraacetate and and syringing human on human gynecology samples obtained by routine cervical scrapes. None of the dispersion methods has, so far, produced an adequate monodispersed cell suspension without unacceptable cell loss.

The National Cancer Institute-supported Flow Cytometry Network for Bladder Cancer concluded that when properly used, DNA flow cytometry of bladder irrigation specimens can be a clinically useful laboratory procedure to monitor patients with bladder cancer. It recommended the use of this technique in managing patients with low-stage disease, particularly flat carcinoma in situ. The method has limited value in managing patients with high-stage (i.e., muscle-invasive) carcinoma; it is not recommended for screening subjects in the absence of a clinical suspicion of or a history of bladder tumors. DNA histograms alone are not sufficient for diagnosis or clinical action but require correlation with other clinical information. Bladder irrigation specimens collected during cystoscopy or by vigorous barbotage via a number 18 Foley catheter may be processed for flow cytometric analyses. Criteria for sampling adequacy have been established and are presented in this report. Optimal results are obtained with fresh specimens that are stained and examined promptly after collection. Preservation procedures are described for cases in which fresh specimens cannot be evaluated. Used with appropriate quality-control measures, commercially available flow cytometers can provide clinically useful information. Staining protocols using propidium iodide are recommended by the Network. Staining protocols are described for isolated nuclei and whole cells (see Appendix). The presence of bladder cancer is signaled by the identification of cell populations with clearly aneuploid DNA content. Quality-control measures and issues of inter- and intralaboratory differences in histogram configuration and analysis must be considered in the interpretation of results. Although the Network participants recognize the potential value of additional markers, these were not evaluated.

Flow cytofluorometric analysis was used to determine the distribution of the DNA content in cells from selected areas of normal human brain and in benign and malignant brain tumors. Propidium iodide was employed as DNA fluorochrome and the analysis was carried out on a suspension of single cells. Normal, nonstimulated human lymphocytes were used as diploid controls. With nonneoplastic tissue an average of 91% of the cells were diploid (presumably in G0 or G1 stage of the cell cycle). The cells of most benign tumors were mainly diploid (77–98%), nine specimens of pituitary adenomas had large numbers of aneuploid cells. In glioblastoma multiforme the proportion of diploid cells was significantly diminished and polyploid cells were frequently seen. Similar results were obtained in other malignant tumors, with metastatic tumors showing the greatest ploidy variation, which included triploid, tetraploid, and hypertetraploid cells. The analytical method used provides valuable information of significant clinical importance on the DNA distribution in brain tumor cells.

Flow cytometric techniques were used to compare the DNA content, size and viability of meningioma cells obtained directly from surgical specimens with the same cells after a period of culture. Cells isolated from the original meningiomas and cells in primary culture were similar with regard to size and DNA content, regardless of the histologic subclassification of tumor. The cell populations were essentially diploid with a small proportion of tetraploid cells. Viable cells were smaller and more uniform in size than the nonviable cells. An increase in the number of cells having an elevated DNA content was seen with cultures repeatedly transferred. The latter results suggest that any transfer of information from long-term cultured meningioma cells to the in vivo situation must be done with caution.

Piezoelectric materials (piezo-materials) convert mechanical energy into electrical energy via the mechanism of piezoelectricity, and this electrical energy may be dissipated through a connected load resistance. The energy dissipation through this mechanism is termed piezo-damping. New models based on this energy conversion and dissipation have been proposed to characterize the damping behaviour of the piezo-materials. An equivalent electrical circuit model is put forward to determine the required load resistance, and a mechanical spring-dashpot model is used to describe the damping capacity of the piezo-materials. Equations were derived to predict optimal resistance load, maximum damping ratio and the shift of the resonance frequency. A two-degree-of-freedom (2-DOF) experimental set up was developed to test the validity of the models. The experimental results agree very well with the theoretical predictions. The piezo-damping mechanism exhibits potentially a high damping capacity.

We report a method of in situ hybridization (ISH) of 10-year-old archival cervical smears with a cocktail of nick-translated human papillomavirus (HPV) DNA types 6, 11, 16, 18, and 31. The method, which does not require destaining, results in excellent preservation of morphological detail with only 2% cell loss. Methods of smear treatment and detection of the biotinylated probe with a multistep avidin-biotin-immunoperoxidase method are described. Biotinylated PBR 322 plasmid and biotinylated human DNA were used as negative and positive controls in each run. Twenty-nine of 50 smears (58%) showing changes consistent with CIN I-II were positive for HPV. Fourteen corresponding cervical biopsies were also studied by ISH, seven corresponding to HPV-positive smears and seven to HPV-negative smears. HPV DNA was demonstrated in six of seven biopsies (87%) from the positive group but none could be demonstrated in the negative group. We conclude that retrospective study can be performed on routine alcohol-fixed, Papanicolaou-stained cervical smears with biotinylated HPV probes with excellent cell preservation, minimal cell loss, and high degrees of specificity.

In order to obviate some of the technical problems associated with preparation of monocellular cell suspensions required for flow fluorometry, isolation of nuclei from several types of benign and malignant human tissues was undertaken. Satisfactory preparations of nuclei were obtained from epithelia of the uterine cervix and colon and from lung tissue using the citric acid method. The sucrose method was effective with colonic epithelium only. Distribution of deoxyribonucleic acid content in these nuclei was measured based on green fluorescence of acridine orange and red fluorescence of propidium iodide in a Bio-Physics Cytofluorograph. Essentially diploid patterns of deoxyribonucleic acid distribution were observed for all benign samples regardless of tissue origin whereas the malignant samples gave histograms suggestive of abnormal deoxyribonucleic acid distribution. Preliminary observations on distribution of single-stranded nucleic acids using acridine orange red fluorescence showed marked differences between populations of benign and malignant nuclei. Isolated nuclei appear to be suitable for flow-through microfluorometric analysis and offer some significant advantages over intact cells.

The use of antibodies permits the study of oncogene product expression in cells and tissues. However, quantitation of the levels of expression in immunohistochemical preparations is beset by difficulties, and the available scoring system provide semiquantitative data at best. Here we describe the use of computer-assisted image analysis for determination of oncoprotein levels in a model system and compare the results with those generated by flow cytometric analysis. The oncogene products measured are located in the nucleus (c-myc p62 and c-fos p55), the inner surface of the membrane (c-ras p21), and both sides of the membrane (c-erbB-2 p185). In each instance, both analytic modalities yielded concordant results. Our data indicate that computer-assisted image analysis is a useful tool for quantitating cell components in immunohistochemical preparations.

This paper develops concepts and equations for the characterisation of a frequency shifting force shaker which can be employed to excite low frequency structures into resonance. Force which is developed at a high frequency can be employed for excitation at a very low frequency. Frequency shifting is accomplished by moving a shaker to and fro in a reciprocating manner parallel to the structure which it is exciting while the shaker force acts perpendicular to the structure. Simple equations which relate the generalised force ratio to a length ratio are developed along with the positions on a structure where a frequency shifting shaker should be placed. This information allows the engineer some simple choices for the design and operation of a frequency shifting shaker. Also, this investigation develops criteria for which the frequency shifting shaker outperforms an ordinary shaker operating at the natural frequency of a structure.

A procedure has been developed to measure dynamic strain in a beam by the use of two accelerometers placed on the beam and frequency response functions between them which relate measured accelerations at different positions to the fixed reference acceleration position. The reference acceleration is then employed to give the acceleration at the other positions. The experimental data along with the complete bending wave solution for an Euler beam enables one to calculate all the terms of the bending wave solution by the use of a matrix inverse. The solution is then used to calculate the dynamic strain in the beam for a random force input. Predictions of strain by using the procedure are compared with experimental measurements of strain obtained by using strain gauges. These comparisons show that the procedure predicts measured strain well for most frequencies, and for the near field and far field regions of the clamped boundaries and the point of force application.

Computer-assisted image analysis was used to demonstrate in exponentially proliferating human tumor cells the uneven postmitotic apportionment of several oncogene-encoded proteins (ras p21; erbB-2 p185; fos p55; myc p62). This observation may provide the explanation for the high degree of heterogeneity of postmitotic cells and the asynchrony in cell cycle traverse of cultured cells.

A model has been devised to study the in vitro formation of desmonsomes. The model is based on the differential labeling of two subpopulations of a desmosome-forming human cancer line (C4I). The labeled subpopulations are dispersed, preincubated separately on a shaking water bath for 24 h to allow the internalization of desmosome fragments and the repair of the cell surface, and then mixed, and allowed to aggregate. Aliquots of the mixed suspension are fixed at various intervals. The time between mixing and fixation represents the maximum age of any junction between dissimilarly labeled cells. The beginnings of desmosome formation were observed within a few minutes after the beginning of aggregation. Close apposition of cell membranes was seen immediately after mixing, followed within 15 min by the appearance of a submembrane density in one or both of the interacting cells. Intracytoplasmic filament formation takes place at between 15 and 30 min. Desmosome formation is complete by 90 min. The process is accompanied by a progressive widening of the extracellular space and the desification and organization of the extracellular material and the submembrane plaques.

Abstract: The piezoelectric ceramic (piezoceramic) component of a polymer-piezoelectric ceramic composite converts mechanical energy into electrical energy and this electrical energy is dissipated as heat in a load resistance, R x, simulated by a shunted resistance, but provided in practice by a conductive polymer composite matrix. The composite therefore dissipates the input mechanical energy via the damping mechanism provided by piezoelectric ceramic-conductive matrix material, as well as the conventional viscoelastic damping provided by the polymer. Mathematical models have been developed to characterize the damping behaviour of the composites, and the maximum damping ratio of composites can be as high as 23%. A two degrees-of-freedom (2DOF) experimental setup was developed to test the validity of the models. The experimental results are in good agreement with the theoretical predictions.

Presents a humorous story about a truck driver.