Harry Beckers

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Foods and food ingredients with low water activity (a(w)) have been implicated with increased frequency in recent years as vehicles for pathogens that have caused outbreaks of illnesses. Some of these foodborne pathogens can survive for several months, even years, in low-a(w) foods and in dry food processing and preparation environments. Foodborne(More)
Trigeminal nerve terminals in the rat pterygopalatine ganglion (PPG) were ultrastructurally identified using anterograde tracing with Phaseolus vulgaris-leucoagglutinin (PHA-L). Electron microscopic immunohistochemistry was used to demonstrate the presence of substance P (SP) and calcitonin gene-related peptide (CGRP) in nerve terminals of the PPG. Adjacent(More)
The peripheral and central efferent projections of the rostral part of the Edinger-Westphal nucleus in the rat were investigated at the light and electron microscopic level by means of iontophoretic injections of the anterograde tracer Phaseolus vulgaris-leucoagglutinin and retrograde tracer injections of Fast blue and Nuclear yellow into the facial nucleus(More)
Food-borne diseases affect the health and welfare of hundred thousands of people and result in considerable economic loss. Salmonella and Campylobacter are by far the most important causes of food-borne illness. Raw foods of animal origin are the major sources of these pathogens. Mishandling of foods in kitchens contributes to food-borne disease outbreaks.(More)
The sympathetic innervation of the choroid was investigated by means of the anterograde tracer 3H-leucine, injected into the rostral part of the superior cervical ganglion. The tracer was autoradiographically visualized at the light- and electron-microscopic levels. Labelled unmyelinated fibres were found in the choroid and labelled terminals were observed(More)
The peripheral nervous system is classically separated into a somatic division containing both afferent and efferent pathways and an autonomic division composed of efferents only. The somatic afferent division is divided in A- and B-neurons. The B-neurons are supposed to be autonomic afferents as part of a reflex system involved in homeostasis. Recent data(More)
The influence of xylitol on glucose metabolism of Streptococcus mutans C67-1S was studied in vitro and in rats in vivo. In vitro there was an inhibition by xylitol of the growth rate and acid production of S. mutans C67-1S, but in vivo no effect on the initial growth rate could be demonstrated. In vivo there was a delay in the start of growth of S. mutans(More)
Performance tests are logistically complex and time consuming. To reach adequate reliability long tests are imperative. Additionally, they are very difficult to adapt to the individual learning paths of students, which is necessary in problem-based learning. This study investigates a written alternative to performance-based tests. A Knowledge Test of Skills(More)
Germfree Osborne-Mendel rats were monoassociated with Actinomyces viscosus or Streptococcus mutans. The adherence and subsequent growth of these organisms on the tooth surface was studied by means of total viable cell counts. Both A. viscosus and S. mutans showed a lag phase and an exponential growth phase, similar to logarithmic growth in batch cultures.(More)