Modelling selective activation of small myelinated nerve fibres using a monopolar point electrode

The aim of this study is to investigate theoretically the possibility for activation of small myelinated nerve fibres without activating larger ones when stimulating a nerve fibre bundle using a monopolar point electrode. Therefore, the sensitivity of excitation and blocking threshold currents of nerve fibres to fibre diameter, electrode-fibre distance and pulse duration has been simulated by a computer model. A simple infinite, homogeneous volume conductor and a cathodal point source were used in combination with a model representing the electrical properties of a myelinated nerve fibre. The results show that selective activation of small myelinated fibres may be possible in a region at some distance from the electrode

Mood, definiteness and specificity: a linguistic and a philosophical account of their similarities and differences

In diesem Beitrag beschreiben wir aus linguistischer Perspektive das Verhältnis von einigen grammatischen Kategorien des Satzes (Realis) und der Nominalphrase (Definitheit, Spezifizität) im Hinblick auf den Status ihrer Referenten in der Diskurswelt, und überlegen anschliessend die ontologische Signifikanz der linguistischen Fakten. Unser Zugang unterscheidet sich in drei wichtigen Hinsichten von vorliegenden Arbeiten. Wir bieten erstens eine Erklärung für die symmetrischen und anti-symmetrischen (invers symmetrischen) Beziehungen, die zwischen Realis (bzw. Irrealis) und Definitheit (bzw. Indefinitheit) bestehen. Zweitens zeigen wir, dass keine Erklärung dieser Beziehungen ohne den Einbezug der grammatischen Kategorie der Spezifizität auskommen kann. Schliesslich untersuchen wir, in welchem Mass die inferentiellen Aspekte der linguistischen Symmetrien und Anti-Symmetrien ontologisch relevant sind, welche Schwierigkeiten sie für das ontologische Standardverständnis von Possibilia aufwerfen, und zeigen, dass eine Ontologie, die mit dynamischen und unbestimmt lokalisierten Individuen verfährt, den linguistischen Daten offenbar besser gerecht wird

On the universal structure of human lexical semantics

How universal is human conceptual structure? The way concepts are organized in the human brain may reflect distinct features of cultural, historical, and environmental background in addition to properties universal to human cognition. Semantics, or meaning expressed through language, provides direct access to the underlying conceptual structure, but meaning is notoriously difficult to measure, let alone parameterize. Here we provide an empirical measure of semantic proximity between concepts using cross-linguistic dictionaries. Across languages carefully selected from a phylogenetically and geographically stratified sample of genera, translations of words reveal cases where a particular language uses a single polysemous word to express concepts represented by distinct words in another. We use the frequency of polysemies linking two concepts as a measure of their semantic proximity, and represent the pattern of such linkages by a weighted network. This network is highly uneven and fragmented: certain concepts are far more prone to polysemy than others, and there emerge naturally interpretable clusters loosely connected to each other. Statistical analysis shows such structural properties are consistent across different language groups, largely independent of geography, environment, and literacy. It is therefore possible to conclude the conceptual structure connecting basic vocabulary studied is primarily due to universal features of human cognition and language use.Comment: Press embargo in place until publicatio

Subject-controlled, on demand, dorsal genital nerve stimulation to treat urgency urinary incontinence:a pilot

Contains fulltext : 171558.pdf (publisher's version ) (Open Access)OBJECTIVES: To evaluate the effect of subject-controlled, on-demand, dorsal genital nerve (DGN) stimulation on non-neurogenic urgency urinary incontinence (UUI) in a domestic setting. MATERIALS AND METHODS: Non-neurogenic patients >18 years with overactive bladder symptoms and UUI were included. Exclusion criteria were mainly stress urinary incontinence. Patients underwent 1 week of subject-controlled, on-demand, DGN stimulation, delivered by a percutaneously placed electrode near the DGN connected to an external stimulator (pulse-rate 20 Hz, pulse-width 300 mus). Patients activated the stimulator when feeling the urge to void and stimulated for 30 s. The amplitude was set at the highest tolerable level. A bladder diary including a severity score of the UUI episodes/void (scores: 0 = none, 1 = drops, 2 = dashes, 3 = soaks) and a padtest was kept 3 days prior to, during, and 3 days after the test period. The subjective improvement was also scored. RESULTS: Seven patients (4 males/3 females) were enrolled, the mean age was 55 years (range 23-73). Six completed the test week. In the remaining patient the electrode migrated and was removed. 5/6 finalized the complete bladder diary, 1/6 recorded only the heavy incontinence episodes (score = 3). 4/6 completed the padtest. In all patients who finalized the bladder diary the number of UUI episodes decreased, in 3/5 with >/=60%. The heavy incontinence episodes (score = 3) were resolved in 2/6 patients, and improved >/=80% in the other 4. The severity score of the UUI episodes/void was improved with >/= 60% in 3/5 patients. The mean subjective improvement was 73%. CONCLUSION: This feasibility study indicates that subject-controlled, on-demand DGN stimulation using a percutaneously placed electrode is possible over a longer time period, in a home setting, with a positive effect on non-neurogenic overactive bladder symptoms with UUI. Although the placement is an easy procedure, it is difficult to fixate the electrode to keep it in the correct position. Improvements in hardware, like a better fixated electrode and an easy to control stimulator, are necessary to make SODGNS a treatment possibility in the future

Novel Designs for Application Specific MEMS Pressure Sensors

In the framework of developing innovative microfabricated pressure sensors, we present here three designs based on different readout principles, each one tailored for a specific application. A touch mode capacitive pressure sensor with high sensitivity (14 pF/bar), low temperature dependence and high capacitive output signal (more than 100 pF) is depicted. An optical pressure sensor intrinsically immune to electromagnetic interference, with large pressure range (0–350 bar) and a sensitivity of 1 pm/bar is presented. Finally, a resonating wireless pressure sensor power source free with a sensitivity of 650 KHz/mmHg is described. These sensors will be related with their applications in  harsh environment, distributed systems and medical environment, respectively. For many aspects, commercially available sensors, which in vast majority are piezoresistive, are not suited for the applications proposed