Cluster randomized clinical trials in orthodontics: design, analysis and reporting issues

Cluster randomized trials (CRTs) use as the unit of randomization clusters, which are usually defined as a collection of individuals sharing some common characteristics. Common examples of clusters include entire dental practices, hospitals, schools, school classes, villages, and towns. Additionally, several measurements (repeated measurements) taken on the same individual at different time points are also considered to be clusters. In dentistry, CRTs are applicable as patients may be treated as clusters containing several individual teeth. CRTs require certain methodological procedures during sample calculation, randomization, data analysis, and reporting, which are often ignored in dental research publications. In general, due to similarity of the observations within clusters, each individual within a cluster provides less information compared with an individual in a non-clustered trial. Therefore, clustered designs require larger sample sizes compared with non-clustered randomized designs, and special statistical analyses that account for the fact that observations within clusters are correlated. It is the purpose of this article to highlight with relevant examples the important methodological characteristics of cluster randomized designs as they may be applied in orthodontics and to explain the problems that may arise if clustered observations are erroneously treated and analysed as independent (non-clustered).

From big smartphone data to worldwide research: The Mobile Data Challenge

This paper presents an overview of the Mobile Data Challenge (MDC), a large-scale research initiative aimed at generating innovations around smartphone-based research, as well as community-based evaluation of mobile data analysis methodologies. First, we review the Lausanne Data Collection Campaign (LDCC), an initiative to collect unique longitudinal smartphone dataset for the MDC. Then, we introduce the Open and Dedicated Tracks of the MDC, describe the specific datasets used in each of them, discuss the key design and implementation aspects introduced in order to generate privacy-preserving and scientifically relevant mobile data resources for wider use by the research community, and summarize the main research trends found among the 100+ challenge submissions. We finalize by discussing the main lessons learned from the participation of several hundred researchers worldwide in the MDC Tracks.

The timing of significant arch dimensional changes with fixed orthodontic appliances: data from a multicenter randomised controlled trial.

OBJECTIVES To identify the timing of significant arch dimensional increases during orthodontic alignment involving round and rectangular nickel-titanium (NiTi) wires and rectangular stainless steel (SS). A secondary aim was to compare the timing of changes occurring with conventional and self-ligating fixed appliance systems. METHODS In this non-primary publication, additional data from a multicenter randomised trial initially involving 96 patients, aged 16 years and above, were analysed. The main pre-specified outcome measures were the magnitude and timing of maxillary intercanine, interpremolar, and intermolar dimensions. Each participant underwent alignment with a standard Damon (Ormco, Orange, CA) wire sequence for a minimum of 34 weeks. Blinding of clinicians and patients was not possible; however, outcome assessors and data analysts were kept blind to the appliance type during data analysis. RESULTS Complete data were obtained from 71 subjects. Significant arch dimensional changes were observed relatively early in treatment. In particular, changes in maxillary inter-first and second premolar dimensions occurred after alignment with an 0.014in. NiTi wire (P<0.05). No statistical differences in transverse dimensions were found between rectangular NiTi and working SS wires for each transverse dimension (P>0.05). Bracket type had no significant effect on the timing of the transverse dimensional changes. CONCLUSIONS Arch dimensional changes were found to occur relatively early in treatment, irrespective of the appliance type. Nickel-titanium wires may have a more profound effect on transverse dimensions than previously believed. CLINICAL SIGNIFICANCE On the basis of this research orthodontic expansion may occur relatively early in treatment. Nickel-titanium wires may have a more profound effect on transverse dimensions than previously believed.

Management of patients during hunger strike and refeeding phase

OBJECTIVE Hunger strikers resuming nutritional intake may develop a life-threatening refeeding syndrome (RFS). Consequently, hunger strikers represent a core challenge for the medical staff. The objective of the study was to test the effectiveness and safety of evidence-based recommendations for prevention and management of RFS during the refeeding phase. METHODS This was a retrospective, observational data analysis of 37 consecutive, unselected cases of prisoners on a hunger strike during a 5-y period. The sample consisted of 37 cases representing 33 individual patients. RESULTS In seven cases (18.9%), the hunger strike was continued during the hospital stay, in 16 episodes (43.2%) cessation of the hunger strike occurred immediately after admission to the security ward, and in 14 episodes (37.9%) during hospital stay. In the refeed cases (n = 30), nutritional replenishment occurred orally, and in 25 (83.3%) micronutrients substitutions were made based on the recommendations. The gradual refeeding with fluid restriction occurred over 10 d. Uncomplicated dyselectrolytemia was documented in 12 cases (40%) within the refeeding phase. One case (3.3%) presented bilateral ankle edemas as a clinical manifestation of moderate RFS. Intensive medical treatment was not necessary and none of the patients died. Seven episodes of continued hunger strike were observed during the entire hospital stay without medical complications. CONCLUSIONS Our data suggested that seriousness and rate of medical complications during the refeeding phase can be kept at a minimum in a hunger strike population. This study supported use of recommendations to optimize risk management and to improve treatment quality and patient safety in this vulnerable population.

Injury severity and mortality of adult zebra crosswalk and non-zebra crosswalk road crossing accidents: a cross-sectional analysis

PRINCIPALS Over a million people worldwide die each year from road traffic injuries and more than 10 million sustain permanent disabilities. Many of these victims are pedestrians. The present retrospective study analyzes the severity and mortality of injuries suffered by adult pedestrians, depending on whether they used a zebra crosswalk. METHODS Our retrospective data analysis covered adult patients admitted to our emergency department (ED) between 1 January 2000 and 31 December 2012 after being hit by a vehicle while crossing the road as a pedestrian. Patients were identified by using a string term. Medical, police and ambulance records were reviewed for data extraction. RESULTS A total of 347 patients were eligible for study inclusion. Two hundred and three (203; 58.5%) patients were on a zebra crosswalk and 144 (41.5%) were not. The mean ISS (injury Severity Score) was 12.1 (SD 14.7, range 1-75). The vehicles were faster in non-zebra crosswalk accidents (47.7 km/n, versus 41.4 km/h, p<0.027). The mean ISS score was higher in patients with non-zebra crosswalk accidents; 14.4 (SD 16.5, range 1-75) versus 10.5 (SD13.14, range 1-75) (p<0.019). Zebra crosswalk accidents were associated with less risk of severe injury (OR 0.61, 95% CI 0.38-0.98, p<0.042). Accidents involving a truck were associated with increased risk of severe injury (OR 3.53, 95%CI 1.21-10.26, p<0.02). CONCLUSION Accidents on zebra crosswalks are more common than those not on zebra crosswalks. The injury severity of non-zebra crosswalk accidents is significantly higher than in patients with zebra crosswalk accidents. Accidents involving large vehicles are associated with increased risk of severe injury. Further prospective studies are needed, with detailed assessment of motor vehicle types and speed.

A new Time-Of-Flight Mass Spectrometer (TOF-MS) for noble gas analysis

Noble gas analysis in early solar system materials, which can provide valuable information about early solar system processes and timescales, are very challenging because of extremely low noble gas concentrations (ppt). We therefore developed a new compact sized (33 cm length, 7.2cm diameter, 1.3 L internal volume) Time-of-Flight (TOF) noble gas mass spectrometer for high sensitivity. We call it as Edel Gas Time-of-flight (EGT) mass spectrometer. The instrument uses electron impact ionization coupled to an ion trap, which allows us to ionize and measure all noble gas isotopes. Using a reflectron set-up improves the mass resolution. In addition, the reflectron set-up also enables some extra focusing. The detection is via MCPs and the signals are processed either via ADC or TDC systems. The objective of this work is to understand the newly developed Time-Of-Flight (TOF) mass spectrometer for noble gas analysis in presolar grains of the meteorites. Chapter 1 briefly introduces the basic idea and importance of the instrument. The physics relevant to time-of-flight mass spectrometry technique is discussed in the Chapter 2 and Chapter 3 will present the oxidation technique of nanodiamonds of the presolar grains by using copper oxide. Chapter 4 will present the details about EGT data analysis software. Chapter 5 and Chapter 6 will explain the details about EGT design and operation. Finally, the performance results will be presented and discussed in the Chapter 7, and whole work is summarized in Chapter 8 and also outlook of the future work is given.

Capability of E-Bike Tourism in Switzerland

AIM OF PAPER AND RESEARCH QUESTIONS The primary aim of this investigation was to examine, if tourism in Switzerland can be stimulated by focusing on e-bike offers. Switzerland is an attractive and manifold country for bike tourism. However, there are plenty of hilly and steep areas, where the topography is quite demanding and cycling is predestined to ambitious sportsperson. Less performance-oriented bike tourists are possibly discouraged by the challenges of the landscape. E-bikes seem to be a reasonable alterna-tive to enable less trained person to attend bike tours in steeper regions as well as to keep heterogeneous groups together. E-bikes are already popular in Switzerland for daily routes as the journey to work, but they are not very common in the tour-istic context. The presented investigation evaluates the current standing of supply and demand for e-bike tourism and asks for opportunities and threats in the future development. LITERTURE REVIEW The existing frameworks to analyse capability in the field of sport tourism are limited, because of the broad variation of sports and tourism types. Still several conceptions are valuable to evaluate the opportunities of e-bike tourism in Switzer-land. According to Higham and Hinch (2009) the potential of touristic products and destinations always depends on the interaction among the factors place, people and activity. Standeven and de Knop (1999) support this position by identify-ing the experience of place as a key component of the sport tourism experience. Bull (2005) assumes that place not only affects experience. In his opinion, the specific spatially located resources are even crucial for the existence of nature sports. He identifies four factors determining the attraction of touristic products or destination, as physical characteristics, accessibility and infrastructural arrangements, political and economic resources as well as cultural and perceptual aspects. Concerning the demand side (people) the contemporary research is guided by an individual psychological focus delivering mainly results about motives and the decision making process (e.g. Görtz & Hürten, 2011). RESEARCH DESIGN AND DATA ANALYSIS The presented study is based on a between method triangulation, consisting of qualitative interviews with important stake-holders on the supply side and a cross sectional survey on the demand side. Qualitative interviews were conducted with the first provider of touristic e-bike routes and with the manager of the leading e-bike rental company in Switzerland. The interviews were evaluated by qualitative content analysis according to Mayring (2008). The survey covered a randomized sample of 748 adult persons and focused on interests and needs of potential consumers. The concluding potentials analy-sis combined the results of the interviews and the survey with the findings of literature research. As central outcome the strengths, weaknesses, opportunities and threats were evaluated and presented by SWOT-analysis. RESULTS Results showed that the development of e-bike tourism in Switzerland was not initiated by tourism promoter, but by an innovative e-bike producer. However, also for the manufacturer the fit between landscape (place), product (activity) and visitors (people) was the crucial criterion. The first e-bike tours were offered in a demanding and rural region, in order that the experience of place was able to promote a positive overall experience. Due to the success of the first touristic e-bike products, several tourism regions started to extend their portfolio with e-bike offers. To date a nationwide network for signalised e-bike tours, rental stations and changing stations for rechargeable batteries is established. Despite the attractive offer, the demand is only moderate. The obtained results of the consumer survey pointed at a certain barrier to use e-bikes for tourism activities. The most substantial barrier is the missing affinity for bike tourism in general. Another notable group considering themselves as “fit enough for normal bike tourism”. Nevertheless 55% of the respondent are interested in tour-istic e-bike products. Looking only at people with e-bike tourism experience, even 92% are interested in further activities. DISCUSSION AN CONCLUSION The current study findings are encouraging because they suggest a superior suitability and an attractive level of e-bike tourism products in Switzerland. The results of the consumer survey indicate an increasing demand for e-bike tourism. The investigation also points at some risks, as the rivalry for bike tourism or the raised safety hazard because of the increased driving speed. Summing up, the results support the conclusion, that e-bike tourism will become more important in the com-ing years. However, to reach the goal relevant trends as the requirement for customised offers must be considered and marketing activities are supposed to be extended. REFERENCES Bull, C. (2005). Sport tourism resource analysis. In J. Higham (Ed.), Sport tourism destination: Issues, opportunities and analysis (pp. 25-38). Amsterdam: Elsevier Butterworth-Heinemann. Görtz, M., & D. Hürten (2011). Motive der Radurlauber, psychografische Merkmale und Reiseverhalten. In A. Dreyer, E. Miglbauer & R. Mühlnickel (Hrsg.), Radtourismus. Entwicklungen, Potenziale, Perspektiven (S. 36-43). München: Olden-bourg. Higham, J., & Hinch, T. (2009). Sport and Tourism. Globalization, Mobility and Identity. Amsterdam: Butterworth-Heinemann. Mayring, P. (2008). Qualitative Inhaltsanalyse. Grundlagen und Techniken (10. Aufl.). Weinheim: Beltz Verlag. Standeven, J., & De Knop, P. (1999). Sport Tourism. Campaign: Human Kinetics.

Patientensicherheit in der Shuntchirurgie

Zusammenfassung Hintergrund. Hämodialysepatienten, die operativ mit einem Gefäßzugang versorgt werden müssen, sind eine vulnerable Patientengruppe, die aufgrund von Multimorbidität, der intensiven und oft fragmentierten Behandlung und vieler Schnittstellen ein erhöhtes Risiko für vermeidbare unerwünschte Ereignisse tragen. Fragestellung. Aktuelle Entwicklungen und Maßnahmen zur Förderung der Patientensicherheit mit Fokus auf die Shuntchirurgie. Material und Methoden. Auswertung und Aufarbeitung aktueller Daten zur Patientensicherheit und Instrumenten zu ihrer Förderung. Ergebnisse. Fehler im nicht operativen Management verursachen einen wesentlichen Anteil der unerwünschten Ereignisse. Checklisten, präoperative Seitenmarkierung, Zählkontrollen und interprofessionelle Teamtrainings sind wichtige Instrumente der Patientensicherheit im OP. Standardisierungen von postoperativen Übergaben durch einfache Protokolle können erheblich zur Reduktion von Fehlern und Schädigungen beitragen. Die Sicherheitskultur einer Abteilung ist ein Umgebungsfaktor, der für die Effektivität dieser Sicherheitsbarrieren wesentlich ist. Schlussfolgerungen. Es existieren wirksame Instrumente, die die Patientensicherheit in der Shuntchirurgie fördern. Gerade an den Schnittstellen zur weiteren Versorgung können durch die konsequente Implementierung und Nutzung dieser Maßnahmen und ein aktives Sicherheitsmanagement unerwünschte Ereignisse vermieden werden. Die interprofessionelle und interdisziplinäre Zusammenarbeit und der Einbezug der Patienten sind wichtige Ressource für die Behandlungssicherheit, die stärker genutzt werden sollten.