Optimal secondary coil design for inductive powering of the Artificial Accommodation System

Age-related ailments like presbyopia and cataract are increasing concerns in the aging society. Both go along with a loss of ability to accommodate. A new approach to restore the patients' ability to accommodate is the Artificial Accommodation System. This micro mechatronic system will be implanted into the capsular bag to replace the human crystalline lens. Depending on the patients' actual need for accommodation, the Artificial Accommodation System autonomously adapts the refractive power of its integrated optical element in a way that the projection on the patients' retina results in a sharp image. As the Artificial Accommodation System is an active implant, its subsystems have to be supplied with electrical energy. Evolving technologies, like energy harvesting, which can potentially be used to power an implant like the Artificial Accommodation System are at the current state of art not sufficient to power the Artificial Accommodation System autonomously [1]. In the near future, therefore an inductive power supply system will be developed which includes an energy storage to power the Artificial Accommodation System autonomously over a period of 24 h and can be recharged wirelessly. This Paper describes a new possibility to optimize the secondary coil design in a solely analytical way, based on a new figure of merit. Within this paper the developed figure of merit is applied to optimize the secondary coil design for the Artificial Accommodation System.

[Energy and memory efficient calculation of the accommodation demand in the artificial accommodation system]

Presbyopia and cataract are gaining more and more importance in the ageing society. Both age-related complaints are accompanied with a loss of the eye's ability to accommodate. A new approach to restore accommodation is the Artificial Accommodation System, an autonomous micro system, which will be implanted into the capsular bag instead of a rigid intraocular lens. The Artificial Accommodation System will, depending on the actual demand for accommodation, autonomously adapt the refractive power of its integrated optical element. One possibility to measure the demand for accommodation non-intrusively is to analyse eye movements. We present an efficient algorithm, based on the CORDIC technique, to calculate the demand for accommodation from magnetic field sensor data. It can be shown that specialised algorithms significantly shorten calculation time without violating precision requirements. Additionally, a communication strategy for the wireless exchange of sensor data between the implants of the left and right eye is introduced. The strategy allows for a one-sided calculation of the demand for accommodation, resulting in an overall reduction of calculation time by 50 %. The presented methods enable autonomous microsystems, such as the Artificial Accommodation System, to save significant amounts of energy, leading to extended autonomous run-times.

Development of a stable isotope dilution assay for the quantification of 5-methyl-(E)-2-hepten-4-one: application to hazelnut oils and hazelnuts

A stable isotope dilution assay was developed for the quantitation of the hazelnut odorant 5-methyl-(E)-2-hepten-4-one by mass chromatography using synthesized [(2)H](2)-5-methyl-(E)-2-hepten-4-one as the internal standard. Application of the method on two batches of commercial hazelnut oils, processed from either roasted or unroasted nuts, revealed 6.4 microg 5-methyl-(E)-2-hepten-4-one per kg of unroasted oil whereas 315.8 microg per kg was determined in the roasted nut oil. The about 50-fold higher amount of 5-methyl-(E)-2-hepten-4-one in roasted hazelnut oil suggested the necessity of a thermal treatment to generate the flavor compound. Pan frying of raw hazelnuts (9 to 15 min) or boiling of the crushed nut material for 1 h in water led to an increase of 5-methyl-(E)-2-hepten-4-one by factors of 600 and 800, respectively, thereby corroborating that the major part of the nut flavorant is formed during heat treatment from a yet unknown precursor in hazelnuts.

Dependence of the 12-methyltridecanal concentration in beef on the age of the animal

The content of 12-methyltridecanal (12-MT), which contributes greatly to the characteristic aroma of stewed beef, was determined by a stable isotope dilution assay in meat samples from nine bovine animals of different ages. The results, which were related to the amount of phospholipids (PL), indicate that 12-MT content increases with the age of beef, e.g., from 36 micrograms.g(-1) PL in a 4-month-old calf to 810 micrograms.g(-1) PL in an 8-year-old cow. The increase of 12-MT content in PL per month varied between 8.4 and 10.9 micrograms.g(-1) PL (mean: 9.3 +/- 0.78 micrograms.g(-1) PL). Possibly 12-MT content is suitable as an indicator for the estimation of the age of a beef sample.

Quantitative analysis of caffeic and ferulic acids in oatmeal. Comparison of a conventional method with a stable isotope dilution assay

[13C]Caffeic acid and [13C]ferulic acid were synthesized and then used as internal standards for the determination of these acids (free and esterified) in oatmeal. A comparative study indicated that 84% of the ferulic acid, but only 32% of the caffeic acid, which is more susceptible to oxidation than the former, could be found by a conventional analytical approach.

Chronic recurrent appendicitis. A clinicopathologic study of 47 cases

As part of a retrospective study 47 appendices from patients with a clinical and morphologic diagnosis of chronic recurrent appendicitis were studied by morphologic and immunohistochemical methods. Appendices with chronic recurrent appendicitis histologically show chronic active inflammation with increased numbers of immunocompetent cells, mostly T lymphocytes and subsequent scarring. In addition, there is an increase in the number of neural cells. Apparently the secretion of neurotropic inflammatory mediators, especially by activated and degranulating eosinophils, leads to a stimulation of nociceptive receptors and thus to the clinical symptoms. The diagnosis of recurrent chronic appendicitis is thus warranted in these cases not only clinically but also on the basis of histologic and immunohistochemical findings.

[Value of bone scintigraphy in secondary (intestinal) hyperparathyroidism]

We report on 4 patients with secondary hyperparathyroidism of intestinal origin presenting a characteristical pattern of distribution, namely focal accumulations of 99mTc-methylene diphosphonate on locations typical of Looser's zones. In accordance with other authors we demonstrate the higher sensitivity of skeletal scintigraphy as compared to radiography which is well known from other disorders of bone. We also refer to the problems of differential diagnosis arising when multiple foci are visible on bone scan.