Needle Tip Force Estimation using an OCT Fiber and a Fused convGRU-CNN Architecture

Needle insertion is common during minimally invasive interventions such as biopsy or brachytherapy. During soft tissue needle insertion, forces acting at the needle tip cause tissue deformation and needle deflection. Accurate needle tip force measurement provides information on needle-tissue interaction and helps detecting and compensating potential misplacement. For this purpose we introduce an image-based needle tip force estimation method using an optical fiber imaging the deformation of an epoxy layer below the needle tip over time. For calibration and force estimation, we introduce a novel deep learning-based fused convolutional GRU-CNN model which effectively exploits the spatio-temporal data structure. The needle is easy to manufacture and our model achieves a mean absolute error of 1.76 +- 1.5 mN with a cross-correlation coefficient of 0.9996, clearly outperforming other methods. We test needles with different materials to demonstrate that the approach can be adapted for different sensitivities and force ranges. Furthermore, we validate our approach in an ex-vivo prostate needle insertion scenario.Comment: Accepted for Publication at MICCAI 201

Territorialising brand experience and consumption: negotiating a role for pop-up retailing

The evolving consumption landscape creates challenges for retailers in accommodating their modus operandi to negotiate changing consumer needs, arguably requiring a ‘new’ type of retailing to hopefully facilitate future success. We suggest that an important aspect of such negotiation will be the use of ‘pop-up’ activity, and we critically evaluate the potential of these ephemeral consumption spaces to constitute and shape consumers’ brand-oriented relations and experiences into the future. Informed by the work of Deleuze and Guattari, we take a territorological perspective. Drawing on data from eight UK-based pop-up cases, we analyse: (1) how these temporary ‘territories’ of brand experience are developed and implemented; (2) what differentiates them from other, traditionally conceived, territories of brand experience; and (3) critically evaluate pop-up’s neglected characterisation in terms of a more ‘fluid’ spatial-temporal retail territory, to better understand its role in contemporary consumer culture. We posit that the development of pop-up activities occurs through the coordination of actions of a variety of stakeholders, constituting a spatial-temporal confluence of both material and processual elements to create a ‘refrain’, through the compression and compaction of interior, intermediary, exterior and annexed milieus. In doing so, we offer a new lens through which to view the creation of retail consumption spaces

Heterozygous Loss-of-Function Mutations in DLL4 Cause Adams-Oliver Syndrome.

Adams-Oliver syndrome (AOS) is a rare developmental disorder characterized by the presence of aplasia cutis congenita (ACC) of the scalp vertex and terminal limb-reduction defects. Cardiovascular anomalies are also frequently observed. Mutations in five genes have been identified as a cause for AOS prior to this report. Mutations in EOGT and DOCK6 cause autosomal-recessive AOS, whereas mutations in ARHGAP31, RBPJ, and NOTCH1 lead to autosomal-dominant AOS. Because RBPJ, NOTCH1, and EOGT are involved in NOTCH signaling, we hypothesized that mutations in other genes involved in this pathway might also be implicated in AOS pathogenesis. Using a candidate-gene-based approach, we prioritized DLL4, a critical NOTCH ligand, due to its essential role in vascular development in the context of cardiovascular features in AOS-affected individuals. Targeted resequencing of the DLL4 gene with a custom enrichment panel in 89 independent families resulted in the identification of seven mutations. A defect in DLL4 was also detected in two families via whole-exome or genome sequencing. In total, nine heterozygous mutations in DLL4 were identified, including two nonsense and seven missense variants, the latter encompassing four mutations that replace or create cysteine residues, which are most likely critical for maintaining structural integrity of the protein. Affected individuals with DLL4 mutations present with variable clinical expression with no emerging genotype-phenotype correlations. Our findings demonstrate that DLL4 mutations are an additional cause of autosomal-dominant AOS or isolated ACC and provide further evidence for a key role of NOTCH signaling in the etiology of this disorder

The pink and white aesthetics of a new zirconia implant

Zirconia implants can offer a good alternative to titanium implants. Due to their specific material properties, they have the potential for a more appealing aesthetic result, which can be particularly important in the anterior zone. In the present study, the pink and white aesthetics of immediately placed zirconia implants in the anterior maxillary zone in 20 patients were assessed on the basis of Pink and White Esthetic Scores (PES and WES). To this end, two clinical photographs were compared: one taken immediately after placement of the permanent crown (mean PES = 12.8; mean WES = 8.5) and the other one taken at a later time (mean PES = 12.8; mean WES = 8.6). No statistically significant difference was found between the two moments. Volunteers found it difficult to correctly identify the implant among the other front teeth. Patients completed a questionnaire regarding the aesthetics of the pink and white implant and they graded the final result with an 8.5 score on a point scale of 0 to 10. The aesthetic appearance of a zirconia implant is excellent and stable over time. Patients are generally satisfied with the result

Pink and White Esthetics of a New Zirconia Implant:A 6-Month to 8-Year Follow-Up

The aim of this study was to analyze changes in pink and white esthetics in the anterior zone through evaluation of an immediately placed zirconia implant using the Pink and White Esthetic Scores (PES and WES) in 20 patients. Two clinical photographs were compared: one taken directly after placement of the permanent crown (mean PES = 12.8; mean WES = 8.5) and the other taken at a later time (mean PES = 12.8; mean WES = 8.6; not significant). Volunteers found it difficult to correctly identify the implant. Patients completed a questionnaire regarding the pink and white implant esthetics. A mean outcome of 8.5 on a point scale of 0 to 10 was found. The esthetic appearance of a restored zirconia implant is excellent and stable over time. Patients are generally satisfied with the result

Optimization of the batch production of silicon fiber-top MEMS devices

We present a fabrication procedure for batch production of MEMS devices directly on top of an optical fiber. The procedure relies on the approach introduced earlier by our group (Gavan et al 2011 Opt. Lett. 36 2898-900), which has been optimized here to obtain higher yield and increased reliability. We describe in details the eight steps of the procedure and we show its application to the fabrication of several cantilever-based structures. Overall, we report a process yield of 80% functioning MEMS devices in our final batch

Minimally Invasive Micro-Indentation: mapping tissue mechanics at the tip of an 18G needle

Experiments regarding the mechanical properties of soft tissues mostly rely on data collected on specimens that are extracted from their native environment. During the extraction and in the time period between the extraction and the completion of the measurements, however, the specimen may undergo structural changes which could generate unwanted artifacts. To further investigate the role of mechanics in physiology and possibly use it in clinical practices, it is thus of paramount importance to develop instruments that could measure the viscoelastic response of a tissue without necessarily excising it. Tantalized by this opportunity, we have designed a minimally invasive micro-indenter that is able to probe the mechanical response of soft tissues, in situ, via an 18G needle. Here, we discuss its working principle and validate its usability by mapping the viscoelastic properties of a complex, confined sample, namely, the nucleus pulposus of the intervertebral disc. Our findings show that the mechanical properties of a biological tissue in its local environment may be indeed different than those that one would measure after excision, and thus confirm that, to better understand the role of mechanics in life sciences, one should always perform minimally invasive measurements like those that we have here introduced

Stiffening of the nucleus pulposus upon axial loading of the intervertebral disc: An experimental in situ study

Mechanical loading is inherently related to the function and degeneration of the intervertebral disc. We present a series of experiments aimed at measuring the effect of a loading/unloading cycle of the intervertebral disc on the mechanical properties of the nucleus pulposus. The study relies on our new minimally invasive microindenter, which allows us to quantify the storage and loss moduli of the nucleus pulposus by inserting an optomechanical probe in an intact (resected) intervertebral disk through the annulus fibrosis via a small needle. Our results indicate that, under the influence of compressive loading, the nucleus pulposus exhibits a more solid-like behavior

Erratum:Publisher Correction: Minimally Invasive Micro-Indentation: mapping tissue mechanics at the tip of an 18G needle (Scientific reports (2017) 7 1 (11364))

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