Circadian rhythms have no effect on cycling performance

The aim of this research was to determine if circadian rhythms have an effect on time trial cycling performance of 15 min duration. Seven males (Mean+/-SD): age, 22.3+/-4.9 yr; height 179.0+/-7.9 cm, body mass 74.5+/-15.5 kg; VO2max 68.0+/-5.7 ml x kg(-1) x min(-1) who were all competitive cyclists or triathletes with previous experience in laboratory testing procedures volunteered to participate in this study. Each of the seven subjects underwent a series of four tests; one VO2 max test, and three 15 min maximal performance tests, at varying times during a 24 hr period. Testing times were at 08.00-10.00; 14.00-16.00 and 20.00-22.00 hours. Heart rate was recorded during the last 10-15 seconds of each minute and blood lactate levels were taken at 5 and 10 min during exercise and again immediately post-exercise. O2 consumption was measured continuously using open circuit spirometry. RPE was measured using the Borg scale at 5 and 10 min during, and again immediately following the completion of testing. Resting oral temperature was the only variable to show a significant time of day effect (p<0.05). Oral temperature during the afternoon was higher than both morning and evening results by 0.76 degrees C and 0.09 degrees C respectively. Total work (kJ) and average power output (W) were recorded at their highest during the morning session and reached a trough during the afternoon session, but these differences were not significant (p = 0.9997 and 0.9972 respectively). The results obtained in this study indicate that while certain biological rhythms are present, they appear to have no effect on this type of cycling performance. Although athletic performance may be enhanced by training programs that are compatible with an individuals body clock, the ability to perform and train at various times has an adaptive response which appears to over-ride these naturally inherent rhythms.     

Comparative immunoreactivity of CD-68 and HMB-45 in malignant melanoma, neural tumors and nevi

The monoclonal antibody CD 68 (KP 1) reacts with fibrohistiocytic and some epithelial neoplasms; its reactivity compared with that of HMB 45 in malignant melanoma (MM) and neural tumors needs further elucidation. Using a streptavidin-biotin-immunoperoxidase procedure, we examined the reactivity of 65 MM (46 conventional, 1 polypoid, 6 desmoplastic [DMM], and 12 metastatic), 21 neurofibromas, 1 neurofibrosarcoma, 10 schwannomas, 1 perineurioma, 2 neurothekeomas, and 14 blue and 26 other nevi for CD-68, HMB-45-defined antigen, S 100 and neurofilament protein. A positive staining for CD 68 was observed in 38 of 42 primary, 5 of 6 DMM, and 11 of 12 metastatic melanomas; 6 of 10 schwannomas; 5 of 10 nevi with junctional component and all 14 blue nevi. All 21 neurofibromas, 1 each neurofibrosarcoma and perineurioma, both neurothekeomas, and all 12 nevi with dermal component were CD 68-negative. HBM 45 was expressed by all 44 primary, none of 6 DMM, and 7 of 12 metastatic melanomas; by none of 10 schwannomas, 6 neurofibromas, 1 neurofibrosarcoma, 1 perineurioma and 2 neurothekeomas. Both junctional nevi, 8 of 10 nevi with junctional components, 1 of 10 dermal components of junctional nevi, and 11 of 13 blue nevi were also HMB 45 positive. Except for 1 perineurioma, S 100 decorated all tumors examined. NF was immunoreactive in 1 of 45 conventional melanomas, 2 of 21 neurofibromas, 2 of 10 schwannomas, and 3 of 10 blue nevi; it was non-reactive in all polypoid, desmoplastic and metastatic melanomas; neurofibrosarcoma, perineurioma, neurothekeoma and other nevi. We conclude that the CD-68-reactivity in primary melanomas, neurofibromas, neurofibrosarcomas, perineuriomas, and nevi was similar to that of HMB 45. The significantly higher CD 68-positivity than of HMB 45 in metastatic and desmoplastic melanomas and schwannomas may be of diagnostic value.     

Bladder pseudotumor in childhood

The application of frozen and radiation sterilized allogenic bone grafts for reconstructions in orthopaedic operations is described. Analysis of results of treatment of 1125 patients was performed. It was found that use of preserved bone allows to reduce the extend and duration of surgery. Nearly total substitution of grafts may be seen in 3 to 8 months after surgery.     

Subcutaneous soft tissue tumours at the site of implanted microchips in mice

An experiment using 4279 CBA/J mice of two generations was carried out to investigate the influence of parental preconceptual exposure to X-ray radiation or to chemical carcinogens. Microchips were implanted subcutaneously in the dorsolateral back for unique identification of each animal. The animals were kept for lifespan under standard laboratory conditions. In 36 mice a circumscribed neoplasm occurred in the area of the implanted microchip. Females were significantly more frequently affected than male mice. An influence of age or different treatment on the s.c. tumour incidence in two mice generations could not be observed. Macroscopically, firm, pale white nodules up to 25 mm in diameter with the microchip in its center were found. Microscopically, soft tissue tumours such as fibrosarcoma and malignant fibrous histiocytoma were detected.     

Intelligent control of the feeding of aluminum electrolytic cells using neural networks

To be efficient, the control of alumina feeding of the electrolytic cell must be based on cell resistance, alumina concentration, and cell state. Most control schemes now in use are based on cell resistance only, and, thus, constitute an open-loop control that lacks robustness because their decision criteria are not explicitly tied to concentration nor to cell state. This results in the cell operating at nonoptimal concentrations, and cell efficiency is diminished. An optimal operation requires a knowledge of concentration and an adjustment of the decision criteria as a function of concentration. A learning vector quantization (LVQ) type of neural network was built and trained to recognize the cell state. Knowing the state of the cell and its resistance, concentration can be estimated using predetermined regression functions. The decision criteria for the control logic are then consequently adapted. A closed-loop control scheme is thus obtained. Results show that, with its control so structured, the cell can operate at or near optimal concentrations independently of its state. This flexible and intelligent character of the neural control can provide a considerable advantage as compared to the standard control.     

Major internal nuclear matrix proteins are common to different human cell types

Cancer invasion and metastasis are associated with matrix degradation. We describe a novel in vivo model of invasion by squamous epithelial neoplastic cells derived from transgenic mice grown on acellular human dermis. Human dermis was subjected to multiple freeze-thaw cycles to render it acellular, maintaining the basement membrane of the former dermal-epidermal junction. Cells representing discrete stages of a multistep transgenic mouse model of epidermal carcinogenesis (neonatal transgenic keratinocytes, moderately/poorly differentiated squamous cell carcinoma, and lymph node metastasis) were seeded onto the basement membrane surface, grown in culture for 4 days, grafted in a subpannicular pocket of athymic mice, and harvested after 3 weeks. Histological analysis demonstrated that neonatal transgenic keratinocytes did not degrade the basement membrane or invade the underlying dermis. In contrast, malignant cells derived from both a moderately differentiated squamous carcinoma and a lymph node metastasis were highly invasive. Immunohistochemical analysis revealed collagenase only in nests of invading malignant cells in contact with the dermal matrix, but not in the tumor mass remaining above the basement membrane, suggesting that this proteinase may be required for stromal invasion. This novel model recapitulates the events seen in malignant invasion: transgenic keratinocytes are unable to penetrate the dermis while cells from a moderately differentiated carcinoma and from lymph node metastasis consistently invade.     

Bone mineral density and survival of elements and element portions in the bones of the Crow Creek massacre victims

The interpretation of archaeologically-derived skeletal series is dependent on the elements and portions of elements preserved for examination. Bone and bone portion survival is affected by factors, both intrinsic and extrinsic to the elements themselves, that influence deterioration and preservation. Among the intrinsic variables, the density of the element and element portion are particularly important with respect to the degree of preservation. Recently reported bone mineral density values from a contemporary human sample are compared to the survival of prehistoric limb bones of the Crow Creek specimens, a fourteenth-century massacre skeletal series. The contemporary density values are positively correlated with Crow Creek element and element portion survival. Two calculations of bone mineral density, however, are more closely related to preservation than a third. Such density information has implications for assessing minimum number of elements and individuals and documenting taphonomic processes.     

A tutorial on wavelets from an electrical engineering perspective.I. Discrete wavelet techniques

The objective of this paper is to present the subject of wavelets from a filter-theory perspective, which is quite familiar to electrical engineers. Such a presentation provides both physical and mathematical insights into the problem. It is shown that taking the discrete wavelet transform of a function is equivalent to filtering it by a bank of constant-Q filters, the non-overlapping bandwidths of which differ by an octave. The discrete wavelets are presented, and a recipe is provided for generating such entities. One of the goals of this tutorial is to illustrate how the wavelet decomposition is carried out, starting from the fundamentals, and how the scaling functions and wavelets are generated from the filter-theory perspective. Examples (including image compression) are presented to illustrate the class of problems for which the discrete wavelet techniques are ideally suited. It is interesting to note that it is not necessary to generate the wavelets or the scaling functions in order to implement the discrete wavelet transform. Finally, it is shown how wavelet techniques can be used to solve operator/matrix equations. It is shown that the “orthogonal-transform property” of the discrete wavelet techniques does not hold in numerical computations