Influence of Taper on the Flexibility of Nickel-Titanium Rotary Files

Introduction: Modern nickel-titanium instruments have various tapers and have been marketed to have superior flexibility from previous generations. Current ISO standards require force measurements at a static point along the file. Unfortunately, root canal anatomy varies and produces multiple forces along the length of the file. The purpose of this study was to determine the influence of taper on the flexibility of various nickel-titanium files. Materials and Methods: The flexibility of stainless steel hand files and nickel-titanium rotary files of various tapers was measured. The sample size was 10 for each type, taper and size. The files were measured at 3, 5 and 7 mm from the tip using a digital caliper and marked with a rubber stopper and a distance of 20mm from the tip was used as the deflection point. Each file was securely fastened on a load-sensing cell and bending was accomplished using a universal testing machine to a maximum deflection of 4.5 mm at a rate of 2 mm/minute under room temperature conditions (22OC ±1OC). Data was collected electronically via Merlin Software and transferred to Microsoft Excel. Statistical analysis was completed with IBM SPSS Statistics software and a two-way analysis of variance (ANOVA) was used as well as a Post-hoc Tukey test. Results: The force and bending moments of EndoSequence .06 taper files was significantly greater (p\u3c0.05) than EndoSequence .04 and stainless steel hand files at all lengths. No significant difference was noted between EndoSequence .04 and stainless steel hand files from 0.25 mm to 3.0 mm. From 3.5 mm to 4.5 mm, the force and bending moments for stainless steel hand files was significantly greater (p\u3c 0.05) than EndoSequence .04 files. Within each file group, the force and bending moments were significantly greater (p\u3c0.05) as the grasp length increased (7 mm\u3e5 mm\u3e3 mm). Conclusions: With a vast array of root canal instruments currently available clinicians should consider the properties of instruments before cleaning and shaping. Nickel-titanium files with tapers greater than 0.04 should not be used for apical enlargement of curved canals because these files are significantly stiffer resulting in an increased chance of canal transportation

A Deep Recurrent Collaborative Filtering Framework for Venue Recommendation

Venue recommendation is an important application for Location-Based Social Networks (LBSNs), such as Yelp, and has been extensively studied in recent years. Matrix Factorisation (MF) is a popular Collaborative Filtering (CF) technique that can suggest relevant venues to users based on an assumption that similar users are likely to visit similar venues. In recent years, deep neural networks have been successfully applied to tasks such as speech recognition, computer vision and natural language processing. Building upon this momentum, various approaches for recommendation have been proposed in the literature to enhance the effectiveness of MF-based approaches by exploiting neural network models such as: word embeddings to incorporate auxiliary information (e.g. textual content of comments); and Recurrent Neural Networks (RNN) to capture sequential properties of observed user-venue interactions. However, such approaches rely on the traditional inner product of the latent factors of users and venues to capture the concept of collaborative filtering, which may not be sufficient to capture the complex structure of user-venue interactions. In this paper, we propose a Deep Recurrent Collaborative Filtering framework (DRCF) with a pairwise ranking function that aims to capture user-venue interactions in a CF manner from sequences of observed feedback by leveraging Multi-Layer Perception and Recurrent Neural Network architectures. Our proposed framework consists of two components: namely Generalised Recurrent Matrix Factorisation (GRMF) and Multi-Level Recurrent Perceptron (MLRP) models. In particular, GRMF and MLRP learn to model complex structures of user-venue interactions using element-wise and dot products as well as the concatenation of latent factors. In addition, we propose a novel sequence-based negative sampling approach that accounts for the sequential properties of observed feedback and geographical location of venues to enhance the quality of venue suggestions, as well as alleviate the cold-start users problem. Experiments on three large checkin and rating datasets show the effectiveness of our proposed framework by outperforming various state-of-the-art approaches

Electrophysiological measurements of peripheral vestibular function—A review of electrovestibulography

Electrocochleography (EcochG), incorporating the Cochlear Microphonic (CM), the Summating Potential (SP), and the cochlear Compound Action Potential (CAP), has been used to study cochlear function in humans and experimental animals since the 1930s, providing a simple objective tool to assess both hair cell (HC) and nerve sensitivity. The vestibular equivalent of ECochG, termed here Electrovestibulography (EVestG), incorporates responses of the vestibular HCs and nerve. Few research groups have utilized EVestG to study vestibular function. Arguably, this is because stimulating the cochlea in isolation with sound is a trivial matter, whereas stimulating the vestibular system in isolation requires significantly more technical effort. That is, the vestibular system is sensitive to both high-level sound and bone-conducted vibrations, but so is the cochlea, and gross electrical responses of the inner ear to such stimuli can be difficult to interpret. Fortunately, several simple techniques can be employed to isolate vestibular electrical responses. Here, we review the literature underpinning gross vestibular nerve and HC responses, and we discuss the nomenclature used in this field. We also discuss techniques for recording EVestG in experimental animals and humans and highlight how EVestG is furthering our understanding of the vestibular system

Remote ischemic conditioning: from experimental observation to clinical application: report from the 8th Biennial Hatter Cardiovascular Institute Workshop

In 1993, Przyklenk and colleagues made the intriguing experimental observation that 'brief ischemia in one vascular bed also protects remote, virgin myocardium from subsequent sustained coronary artery occlusion' and that this effect '.... may be mediated by factor(s) activated, produced, or transported throughout the heart during brief ischemia/reperfusion'. This seminal study laid the foundation for the discovery of 'remote ischemic conditioning' (RIC), a phenomenon in which the heart is protected from the detrimental effects of acute ischemia/reperfusion injury (IRI), by applying cycles of brief ischemia and reperfusion to an organ or tissue remote from the heart. The concept of RIC quickly evolved to extend beyond the heart, encompassing inter-organ protection against acute IRI. The crucial discovery that the protective RIC stimulus could be applied non-invasively, by simply inflating and deflating a blood pressure cuff placed on the upper arm to induce cycles of brief ischemia and reperfusion, has facilitated the translation of RIC into the clinical setting. Despite intensive investigation over the last 20 years, the underlying mechanisms continue to elude researchers. In the 8th Biennial Hatter Cardiovascular Institute Workshop, recent developments in the field of RIC were discussed with a focus on new insights into the underlying mechanisms, the diversity of non-cardiac protection, new clinical applications, and large outcome studies. The scientific advances made in this field of research highlight the journey that RIC has made from being an intriguing experimental observation to a clinical application with patient benefit

A Phonology-based Approach for Isolated Sign Production Assessment in Sign Language

Interactive learning platforms are in the top choices to acquire new languages. Such applications or platforms are more easily available for spoken languages, but rarely for sign languages. Assessment of the production of signs is a challenging problem because of the multichannel aspect (e.g., hand shape, hand movement, mouthing, facial expression) inherent in sign languages. In this paper, we propose an automatic sign language production assessment approach which allows assessment of two linguistic aspects: (i) the produced lexeme and (ii) the produced forms. On a linguistically annotated Swiss German Sign Language dataset, SMILE DSGS corpus, we demonstrate that the proposed approach can effectively assess the two linguistic aspects in an integrated manner

Electrophysiologic profile and efficacy of intravenous dofetilide (UK-68,798), a new class III antiarrhythmic drug, in patients with sustained monomorphic ventricular tachycardia

There is increasing evidence that class III antiarrhythmic agents may be superior to class I agents for the long-term treatment of life-threatening ventricular tachyarrhythmias. This open study evaluated he acute electrophysiologic effects, antiarrhythmic efficacy, and safety of different doses of intravenous dofetilide, a new dass III drug, in 50 patients with sustained monomorphic ventricular tachycardia inducible by programmed electrical stimulation who had previously been unsuccessfully treated with 0 to 7 (median 3) other drugs. Intravenous dofetilide was administered over 60 minutes at he following dose levels: 1.5, 3.0, 6.0, 9.0, and 15.0 mu g/kg. Significant class III activity was apparent at doses of 3.0 to 15.0 mu g/kg, as evidenced by dose-related prolongation of the QTc interval by 13.4% to 14.2%, ventricular effective refractory period by 7.9% to 20.6%, and ventricular functional refractory period by 7.3% to 25.0%. The corresponding mean +/- SD plasma dofetilide concentrations ranged from 1.45 +/- 0.52 to 6.48 +/- 1.31 ng/ml, There was no evidence of reverse use-dependence. At these electrophysiologically active dose levels, intravenous dofetilide suppressed (complete response) or slowed (partial response) inducible ventricular tachycardia in 17 of 41 patients (41%) compared with 0 of 9 patients receiving only 1.5 mu g/kg. The response rate was fairly uniform among the groups receiving 3.0, 6.0, 9.0, and 15.0 mu g/kg. Intravenous dofetilide was hemodynamically well tolerated, Torsades de pointes (which was self-limiting) developed in only 1 patient, who was allocated to receive 15.0 mu g/kg. There were no other proarrhythmic episodes or serious adverse effects. Further evaluation of the therapeutic potential of dofetilide in the management of life-threatening ventricular arrhythmias is justified