[Titanium-alloy vs. CoCr-alloy in removable prosthodontics--a clinical study]

Different types of titanium-alloys instead of CoCr-alloys have been tested as material for the framework of removable partial dentures (RPD). Adequate casting and processing techniques have been developed which enable to fabricate frameworks of complex designs and the problem limits porosity. This opened new possibilities for the use of titanium-alloys with improved properties (E-module). The aim of this study was to summarise the use of titanium in removable prosthodontics and to evaluate prospectively the use of the Ti6A17Nb-alloy for RPDs in a small group of patients. Two identically designed RPDs from CoCr-alloy (remanium GM 800+) and Ti6A17Nb-alloy (girotan L) were produced for ten patients. They had to wear each RPD during six months, first the CoCr-RPD and then the Ti6A17Nb-RPD. A questionnaire (visual analogue scale = VAS) was completed by the patients after one, three and six months of function for each RPD. Prosthetic complications and service needed were recorded. After the end of the entire observation period of twelve months, the patients remained with the Ti6A17Nb-RPD and answered the questionnaire after another six months. All parameters regarding the design of the RPDs were positively estimated by the dentist. Minimal, not significant differences were noted by the patients concerning comfort, stability and retention (VAS). Clinically, no differences in technical aspects or regarding biological complications were observed after six-months periods. The Ti6A17Nb-alloy (girotan L) for the framework of RPDs was judged by patients and professionals to be equivalent to RPDs made from CoCr-alloy. No differences in material aspects could objectively be observed. The Ti6A17Nb-alloy can be beneficial for patients with allergies or incompatibility with one or several components of the CoCr-alloy.

Oxytocin release and lactation performance in Syrian Shami cattle milked with and without suckling

Oxytocin (OT) release and lactation performance in primiparous Syrian Shami cows were evaluated in response to two different machine milking regimes. Six cows were milked in the presence of the calves (PC) and subsequently suckled, whereas six cows were exclusively machine milked without the presence of their calves (WC) until day 91 post partum. Milk yield and milk constituents were determined weekly. The degree of udder evacuation was determined by the succeeding removal of residual milk. PC released OT during the milking process, whereas in WC no OT release was detected throughout the milking process. Consequently, the residual milk fraction was much lower in PC than in WC (11% v. 58%, P<0.05) and daily milk yield until day 91 post partum was higher in PC than in WC (12.6+/-0.3 v. 7.1+/-0.4 kg, P<0.05). In conclusion, Syrian Shami cattle are not suitable to be exclusively machine milked without the presence of their calves.

Cognitive response control in writer's cramp

Disturbances of the motor and sensory system as well as an alteration of the preparation of movements have been reported to play a role in the pathogenesis of dystonias. However, it is unclear whether higher aspects of cortical – like cognitive – functions are also involved. Recently, the NoGo-anteriorization (NGA) elicited with a visual continuous performance test (CPT) during recording of a 21-channel electroencephalogram has been proposed as an electrophysiological standard-index for cognitive response control. The NGA consists of a more anterior location of the positive area of the brain electrical field associated with the inhibition (NoGo-condition) compared with that of the execution (Go-condition) of a prepared motor response in the CPT. This response control paradigm was applied in 16 patients with writer’s cramp (WC) and 14 age matched healthy controls. Topographical analysis of the associated event-related potentials revealed a significant (P < 0.05) NGA effect for both patients and controls. Moreover, patients with WC showed a significantly higher global field power value (P < 0.05) in the Go-condition and a significantly higher difference-amplitude (P < 0.05) in the NoGo-condition. A source location analysis with the low resolution electromagnetic tomography (LORETA) method demonstrated a hypoactivity for the Go-condition in the parietal cortex of the right hemisphere and a hyperactivity in the NoGo-condition in the left parietal cortex in patients with WC compared with healthy controls. These results indicate an altered response control in patients with WC in widespread cortical brain areas and therefore support the hypothesis that the pathogenesis of WC is not restricted to a pure sensory-motor dysfunction.

Effect of dark chocolate on renal tissue oxygenation as measured by BOLD-MRI in healthy volunteers

BACKGROUND Cocoa is rich in flavonoids, has anti-oxidative properties and increases the bioavailability of nitric oxide (NO). Adequate renal tissue oxygenation is crucial for the maintenance of renal function. The goal of this study was to investigate the effect of cocoa-rich dark chocolate (DC) on renal tissue oxygenation in humans, as compared to flavonoid-poor white chocolate (WC). METHODS Ten healthy volunteers with preserved kidney function (mean age ± SD 35 ± 12 years, 70% women, BMI 21 ± 3 kg/m2) underwent blood oxygenation level-dependent magnetic resonance imaging (BOLD-MRI) before and 2 hours after the ingestion of 1 g/kg of DC (70% cocoa). Renal tissue oxygenation was determined by the measurement of R2* maps on 4 coronal slices covering both kidneys. The mean R2* (= 1/T2*) values in the medulla and cortex were calculated, a low R2* indicating high tissue oxygenation. Eight participants also underwent BOLD-MRI at least 1 week later, before and 2 hours after the intake of 1 g/kg WC. RESULTS The mean medullary R2* was lower after DC intake compared to baseline (28.2 ± 1.3 s-1 vs. 29.6 ± 1.3 s-1, p = 0.04), whereas cortical and medullary R2* values did not change after WC intake. The change in medullary R2* correlated with the level of circulating (epi)catechines, metabolites of flavonoids (r = 0.74, p = 0.037), and was independent of plasma renin activity. CONCLUSION This study suggests for the first time an increase of renal medullary oxygenation after intake of dark chocolate. Whether this is linked to flavonoid-induced changes in renal perfusion or oxygen consumption, and whether cocoa has potentially renoprotective properties, merits further study.

A Passive Source Localization System for IEEE 802.15.4 Signal

In this work, we provide a passive location monitoring system for IEEE 802.15.4 signal emitters. The system adopts software defined radio techniques to passively overhear IEEE 802.15.4 packets and to extract power information from baseband signals. In our system, we provide a new model based on the nonlinear regression for ranging. After obtaining distance information, a Weighted Centroid (WC) algorithm is adopted to locate users. In WC, each weight is inversely proportional to the nth power of propagation distance, and the degree n is obtained from some initial measurements. We evaluate our system in a 16m-18m area with complex indoor propagation conditions. We are able to achieve a median error of 2:1m with only 4 anchor nodes.

A Passive WiFi Source Localization System based on Fine-grained Power-based Trilateration

Indoor localization systems become more interesting for researchers because of the attractiveness of business cases in various application fields. A WiFi-based passive localization system can provide user location information to third-party providers of positioning services. However, indoor localization techniques are prone to multipath and Non-Line Of Sight (NLOS) propagation, which lead to significant performance degradation. To overcome these problems, we provide a passive localization system for WiFi targets with several improved algorithms for localization. Through Software Defined Radio (SDR) techniques, we extract Channel Impulse Response (CIR) information at the physical layer. CIR is later adopted to mitigate the multipath fading problem. We propose to use a Nonlinear Regression (NLR) method to relate the filtered power information to propagation distances, which significantly improves the ranging accuracy compared to the commonly used log-distance path loss model. To mitigate the influence of ranging errors, a new trilateration algorithm is designed as well by combining Weighted Centroid and Constrained Weighted Least Square (WC-CWLS) algorithms. Experiment results show that our algorithm is robust against ranging errors and outperforms the linear least square algorithm and weighted centroid algorithm.

Entwicklung und Implementierung von Modellen für ein Skills-Training-Parcours für internistische Assistenzärzte

„Entwicklung und Implementierung von Modellen für ein Skills-Training-Parcours für internistische Assistenzärzte “ V. Maier1 - K. Schnabel2 1 Universitätslinik für Allgemeine Innere Medizin, Inselspital, Bern 2 Berner interdisziplinäres Skills- und Schauspielpatientenzentrum (BiSS), Institut für Medizinische Lehre (IML), Abteilung für Unterricht und Medien (AUM) Einleitung: Im klinischen Alltag sind praktische Fertigkeiten gefordert, um Patienten sicher zu behandeln. Auch in der Schweizer Fachgesellschaft FMH kam es zu einer stärkeren Gewichtung der praktischen Fertigkeiten und müssen jetzt ein Logbuch über Art und Zeitpunkt der Intervention führen [1]. Am Inselspital Bern wurde dafür ein Skillsparcours etabliert, da in vielen Bereichen simulationsbasierte Ausbildungen traditionellen Methoden überlegen ist [2]. Der Skillsparcours besteht aus einem Nachmittag mit 4 nicht-invasiven Prozeduren und einem Nachmittag mit 5 invasiven Prozeduren. Eigens dafür wurden drei Modelle entwickelt und deren Tauglichkeit evaluiert. Fragestellung: Bilden die selbst gefertigten Modelle die Realität ausreichend ab? Material und Methoden: Innerhalb der 9 Posten (5 invasiv und 4 nichtinvasiv) wurden für die 5 invasiven Posten zwei Modelle aus dem Skillslab (BiSS) genutzt (Lumbalpunktion (LP) und Blasenkatheter (BK)) und drei Modelle neu entwickelt (Pleura-(PP), Aszites-(AP) und Knochenmarks-Punktion (KMP)). Die Modelle wurden mit Materialien aus dem Baumarkt entwickelt (Material ca. CHF 50/Stück). Der Aufbau der Modelle soll auf der Tagung demonstriert werden. Die Teilnehmer (N=12) und Dozenten (N=5) wurden zu der Qualität mittels Fragebogen befragt. Dabei wurde die individuelle Vorerfahrung und die Einschätzung der Teilnehmer erfragt. Die Frage zur Eignung des Modells war: „Das Modell war zum Üben geeignet“. Als Skala wurde eine Likert-Skala von 0 bis 5 (1=sehr ungeeignet, 5=sehr geeignet) benutzt. Ergebnisse: Die Assistenzärzte beurteilten die Modelleignung wie folgt (Median (Min;Max)): LP: 5 (4;5) KMP: 4.5 (3;5), PP: 4 (3;5), AP: 4.5 (2;5), BK-Einlage: 4.5 (4;6). Die Oberärzte, die jeweils nur das Modell bewerteten, an welchem sie den Kurs durchführten, beurteilten die Modelleignung wie folgt: LP 5.0, KMP: 5.0, PP 5.0, AP: 4.0, BK-Einlage: 3.0. Diskussion: Alle Modelle wurden sowohl von den Oberärzten als auch von den Assistenzärzten als zum Üben tauglich eingeschätzt. Zwischen den selbst hergestellten Low-Fidelity Modellen und den High-Fidelity Modellen gab es hierein keinen signifikanten Unterschied. Als am wenigsten tauglich wurde von den Oberärzten mit der Simulation der Blasenkatheter-Einlage ein High-Fidelity-Modell bewertet. Schlussfolgerungen: Alle Modelle für die Simulation der Punktionstechniken haben gut bis sehr gut funktioniert. Die selbst hergestellten Modelle bilden die Wirklich zum Üben der Techniken hinreichend gut und nicht schlechter als die High-Fidelity-Modelle ab. Selbst gebaute Modelle mit Materialien aus dem Baumarkt können das sonst sehr materialaufwändige Training mit Simulatoren genauso effektiv aber wesentlich effizienter durchführbar machen. Literatur bei den Autoren (1) Weiterbildungsordnung FMH 2014 (letzte Revision 4. September 2014). www.fmh.ch/files/pdf15/wbo_d.pdf (2) McGaghie WC, Issenberg SB, Cohen ER, Barsuk JH, Wayne DB (2011) Does simulation-based medical education with deliberate practice yield better results than traditional clinical education? A meta-analytic comparative review of the evidence. Acad Med. 2011 Jun;86(6):706-11