The failure of fibre composites and adhesively bonded fibre composites under high rates of test

The failure of fibre composites and adhesively bonded fibre composites under high rates of test, up to rates of about 15 m s^–1 were studied in detail. The present paper. Part I of the series, considers the experimental aspects of the mode I fracture of the fibre composite materials and joints. Part II will analyse the dynamic effects which are invariably associated with high-rate tests, and will show how these effects influence the observed behaviour of the test specimens. Part III will report the results from mode II and mixed-mode I/II tests on the fibre composite materials.     

High-resolution XANES studies on vanadium-containing haloperoxidase: pH-dependence and substrate binding

High-resolution X-ray absorption vanadium K-edge spectra were recorded for samples of vanadium-containing bromoperoxidase from the brown alga, Ascophyllum nodosum, at pH 9, 7, 5 and 4, as well as for enzyme samples containing the substrates, hydrogen peroxide and bromide. The well-resolved features of the XANES spectra are discussed. The pH-dependence of the structure of the active site has been studied revealing no significant change of the absorption features. We were able to detect an interaction of H2O2 with the vanadium site of the bromoperoxidase using XAS spectroscopy, whereas addition of bromide causes no energy shift of the XANES spectrum. The possible role of vanadium during the enzymatic reaction is discussed on the basis of our results.     

Expression and developmental profile of antioxidant enzymes in human lung and liver

Effect of recombinant human basic fibroblast growth factor (bFGF) on fracture healing was investigated using a tibial fracture in beagle dogs. Transverse fractures in the middle of the diaphyses were created in the right tibiae and bFGF was injected into the fracture sites at a single dose of 200 micrograms. The time course of changes in callus volume and morphology of the fracture sites were evaluated at weeks 2, 4, 8, 16, and 32 after treatment, and the fracture strength was analyzed at weeks 16 and 32. At week 2, a radiogram of the fracture site showed obvious membranous ossification in the group injected with bFGF. Basic FGF extended the callus area at week 4 and increased the bone mineral content (BMC) in the callus at week 8. bFGF also increased the osteoclast number in the periosteal callus at weeks 2 and 4. In the bFGF group, a maximal increase in the osteoclast index was found at week 4, and an identical increase was recognized in the control group at weeks 8 and 16. These findings strongly suggested that bFGF stimulated not only callus formation but osteoclastic callus resorption. BMC in the bFGF group was followed by a rapid decrease from week 8, while that in the control group was identical from week 4. Fracture strength of the bFGF group showed significant recovery by week 16, and recovery was still evident by week 32. We conclude that bFGF promotes the fracture healing in dogs by the stimulation of bone remodeling.     

Designs as a searchable intellectual property right

This article reviews the nature and value of design protection, some current developments, how design protection relates to and complements other forms of intellectual property (IP), and how searches can be made.     

Monkey cutaneous SAI and RA responses to raised and depressed scanned patterns: effects of width, height, orientation, and a raised surround

Monkey cutaneous SAI and RA responses to raised and depressed scanned patterns: effects of width, height, orientation, and a raised surround. J. Neurophysiol. 78: 2503-2517, 1997. The aim of this study was to examine the slowly adapting type I (SAI) and rapidly adapting (RA) primary afferent representation of raised and depressed surface features. Isolated, raised, and depressed squares and small raised squares with a circular surround were scanned across the receptive fields of SAI and RA mechanoreceptive afferents innervating the distal fingerpads of the rhesus monkey. Pattern height ranged from -620 to +620 micron and width ranged from 0.2 to 7.0 mm. The surround radii ranged from 3.0 to 7.0 mm. Previous combined psychophysical and neurophysiological studies have provided evidence that SAI afferent responses are responsible for the perception of spatial form and texture and that RA afferents are responsible for the detection of stimuli that produce minute skin motion (flutter, slip, microgeometric surface features). Our results strengthen these hypotheses. Response properties shared by both SAI and RA afferent types were that both responded only to the edges of the larger raised and depressed patterns, both responded to falling edges half as vigorously as to rising edges, both responded to rising and falling edges with impulse rates that were proportional to the sine of the angle between the edge and the scanning direction, and both had suppressed responses to a small raised surface feature when a raised surround was closer than 6 mm. Response differences consistent with the hypothesis that SAI afferents are specialized for the representation of form were that SAI responses were confined to areas around the features that evoked them in areas that were 40-50% smaller than the comparable RA response areas, SAI responses were more than four times more sensitive to stimulus height than were RA afferents over the range from 280 to 620 micron, and SAI (but not RA) afferents responded 20-50% more vigorously to corners than to edges. Response differences consistent with the hypothesis that RA afferents are specialized for the detection of minute surfaces features were that only RA afferents responded to very small surface depressions, depressed squares 0.8 mm wide, that were detectable by palpation. Mechanisms underlying the many differences in SAI and RA response properties are discussed.     

Epileptic seizures, arthrogryposis, and migrational brain disorders: a syndrome?

INTRODUCTION: Arthrogryposis multiplex congenita (AMC) may be associated with multiple developmental defects. In some severely affected newborns with AMC, autopsy studies have suggested a common mechanism of malmigration at the spinal and cerebral levels. To our knowledge, a constellation of arthrogryposis, epileptic seizures, and brain migrational anomalies in adult patients has not previously been described in a clinical material. MATERIAL AND METHODS: Six consecutive adult patients with arthrogryposis multiplex congenita and epileptic seizures form the basis of the present study. Five patients had joint contractures and reduced muscle volume restricted to the lower extremities, whereas one patient had predominantly upper extremity affection. They were studied with magnetic resonance imaging (MRI), EEG, EMG, a neuropsychological test battery, and chromosome analysis. RESULTS: Four of them had clear evidence of migrational brain disorders, demonstrated by MRI, in three of them roughly corresponding to the focal epileptiform EEG activity. Five of the patients had partial seizures, whereas one only had generalized tonic-clonic seizures. The MRI findings included polymicrogyria, pachygyria, and fused schizencephaly. Four had neurogenic EMG changes, one had myopathic EMG features, and one had an unremarkable EMG pattern in affected muscles. All patients with demonstrable migrational disorders showed abnormal neuropsychological features. Three patients were mentally retarded. A chromosome abnormality in the form of a ring chromosome 18 was present in one patient. CONCLUSION: We suggest that AMC, epileptic seizures, and migrational brain disorders may form the integral parts of a hitherto undescribed syndrome in adults. A wide-spread defect in neuronal migration along the entire neural axis may be the underlying mechanism of the cerebral and the peripheral symptoms.     

Oscillatory insulin secretion after pancreas transplant

In vivo studies of beta-cell secretory function have demonstrated the existence of rapid insulin oscillations of small amplitude recurring every 8-15 min in normal subjects. This study evaluated the effects of pancreas transplant on rapid insulin oscillations. Samples for glucose, insulin, and C-peptide were drawn during constant glucose infusion at 2-min intervals for 90 min from six successful Px patients with type I diabetes mellitus, from six normal nondiabetic control subjects, and from three Kx subjects. A computerized algorithm (ULTRA) was used for pulse detection. In the Px group, the average insulin pulse period was significantly shorter than in both the control and Kx groups (Px 8.1 +/- 0.5, control 12.5 +/- 0.7, Kx 12.4 +/- 0.5 min, P < 0.0005). By contrast, the C-peptide pulse periods (Px 16.8 +/- 2.3, control 14.7 +/- 1.2, Kx 15.3 +/- 1.5 min) were similar in the three groups. Spectral analysis confirmed that the frequency of the insulin pulses was increased in the Px group. The absolute amplitude of the insulin pulses was greater in the Px group (P < 0.001) while the amplitude of the C-peptide pulses did not differ between the groups. Cross-correlation analysis demonstrated maximal correlation coefficients at a lag of 0 min between insulin and C-peptide (control r = 0.33, P < 0.0001; Kx r = 0.17, P = 0.06) and between insulin and glucose (control r = 0.21, P < 0.001; Kx r = 0.20, P < 0.02) in the control and Kx groups, respectively, whereas no significant correlations were observed at any lag in the Px group.(ABSTRACT TRUNCATED AT 250 WORDS)