RESUMEN

[This corrects the article DOI: 10.1529/biophysj.106.094698.].

RESUMEN

The past twenty years have witnessed a huge increase in research activity on the government health system in Israel. Consequently, a number of questions of enhanced importance arise: to whom the resultant IP (intellectual property) belongs?--to the researcher or the employer? and what compensation should the researcher receive for his inventive efforts? The government found many cases where the IP was registered in the name of the inventor/researcher, thus denying the government ownership of the IP. In 2009, the government sued Omryx over ownership of such an IP. Following these developments, the government issued new rules for management of IP in the government health system. They came into effect in November 2010. In many respects, the new rules are more stringent than the Israeli Patent Law in respect of the inventor. However, the stipulation of awards to the inventor in the new rules is generous. In order for the new rules to be enforceable, the following guidelines are recommended: The new rules should be more aligned with the Patent Law and with the meaning given to the Law by the judicial system, and There is need for the assent and awareness of health system workers to the conditions set out in the new rules, preferably in the form of new work contracts that clearly and concurrently delineate the worker's duties, particularly those pertaining to IP.

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RESUMEN

Mucus propelling cilia are excitable by many stimulants, and have been shown to increase their beating frequency up to threefold, by physiological extracellular stimulants, such as adenosine-triphosphate, acetylcholine, and others. This is thought to represent the evolutionary adaptation of mucociliary systems to the need of rapid and efficient cleansing the airways of foreign particles. However, the mucus transport velocity depends not only on the beat frequency of the cilia, but on their beat pattern as well, especially in the case of mucus bearing cilia that beat in a complex, three-dimensional fashion. In this study, we directly measured the force applied by live ciliary tissues with an atomic force microscope, and found that it increases linearly with the beating frequency. This implies that the arc swept by the cilia during their effective stroke remains unchanged during frequency increase, thus leading to a linear dependence of transport velocity on the beat frequency. Combining the atomic force microscope measurements with optical measurements, we have indications that the recovery stroke is performed on a less inclined plane, leading to an effective shortening of the overall path traveled by the cilia tip during this nontransporting phase of their beat pattern. This effect is observed to be independent of the type of stimulant (temperature or chemical), chemical (adenosine-triphosphate or acetylcholine), or concentration (1 microM-100 microM), indicating that this behavior may result from internal details of the cilium mechanical structure.

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RESUMEN

Forces applied by intact mucus-propelling cilia were measured for the first time that we know of using a combined atomic force microscopy (AFM) and electrooptic system. The AFM probe was dipped into a field of beating cilia and its time-dependent deflection was recorded as it was struck by the cilia while the electrooptic system simultaneously and colocally measured the frequency to ensure that no perturbation was induced by the AFM probe. Using cilia from frog esophagus, we measured forces of approximately 0.21 nN per cilium during the effective stroke. This value, together with the known internal structure of these cilia, leads to the conclusion that most dynein arms along the length of the axoneme contribute to the effective stroke of these cilia.

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