Characteristics of multicellular spheroids formed by primary cultures of human thyroid tumor cells

Features of multicellular tumor spheroids (MCTS) differed depending on their types of cells. MCTS formed by 4000 human thyroid primary culture epithelial tumor cells displayed diameters between 0.31 and 0.33 mm within 2 days regardless of the stage of malignancy of the originating tumors. Their cellular composition reflected that of the originating tumor in regard to DNA content and the expression of cytokeratin, vimentin, as well as thyroglobulin. During the following 3 weeks, their sizes increased up to diameters of 0.42 mm when their cells had been derived from carcinomas, and MCTS originating from adenomas stopped growing within the next 2 days. After 8 days of incubation, proliferating cells were only found in carcinoma MCTS. The cells were randomly distributed over the total volume of the spheroids, which displayed irregular cell arrangements but not concentric cell layers and did not form necrotic centers.     

A laser displacement sensor using the self-mixing effect for modalanalysis and defect detection

A low-cost, simple, noncontact displacement sensor using the self-mixing effect inside a cw single-mode laser diode has been developed for modal analysis and defect detection. The resonance frequencies of thin clamped metallic plates have been determined with a resolution of 0.2 Hz. With such targets, classic spectrum analyzers generate a measurement error up to 10% because of the weight of the accelerometer. The frequency-shift of the fundamental resonance frequency between a standard plate and the same one with a known defect can also be measured, the modal vector associated to this frequency being distorted at the place of the defect     

Normal regional anatomy of the shoulder

Transitional cell carcinoma of the bladder is associated with a high relapse rate, locally and systemically, particularly in patients with nodal or soft-tissue involvement, despite radical cystectomy. The responsiveness of the disease to chemotherapy in the metastatic setting has stimulated the use of systemic therapy in earlier stage disease, either before (neoadjuvant) or after (adjuvant) definitive local therapy. Interpretation of the data is hampered by low patient accrual to randomized trials, lack of standardization of local treatment modalities, and the use of a variety of chemotherapy agents and regimens pointing to the difficulty in reaching a consensus as to what constitutes standard therapy. In this article, we review the use of adjuvant and neoadjuvant chemotherapy, the advantages and disadvantages of both approaches, and the recommendations that can be made based on available data. New approaches to improving survival, potentially with organ preservation, include the development of more effective chemotherapy, and the identification of prognostic features-clinical or biologic-that might be a better guide to patient selection.     

A hierarchical approach to dynamic optimization of power systems

The power production system in The Netherlands is characterized by a relatively large number of thermal power-generating units, the presence of autonomous power stations, a strong national grid and a fluctuating daily load. The calculation of the most economic production policy for one or two days ahead, given all cost functions and the predicted demand for electricity, leads to a nonlinear mixed-integer optimization problem. A real solution can only be found at the expense of rather unrealistic values for computing time and memory. To cope with this problem, a hierarchical approach is described that is able to solve problems with up to 100 units and 24 periods.     

High-performance liquid chromatographic determination of L-aspartyl-L-phenylalanine methyl ester in various food products and formulations

A simple, rapid, and specific high-performance liquid chromatographic (HPLC) procedure is described for the analysis of the chemical sweetener L-aspartyl-L-phenylalanine methyl ester (aspartame). Using a strong cation exchange column and pressures less than 1000 psig, an analysis can be performed in less than 15 min. The technique has been applied to a wide range of food products and formulations. No interferences were found in the samples studied. Recoveries are quantitative, and the coefficients of variation for replicate analyses are less than or equal to 2.5%.