1,306 research outputs found

    Microsurgery for intracranial aneurysms: A qualitative survey on technical challenges and technological solutions

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    INTRODUCTION: Microsurgery for the clipping of intracranial aneurysms remains a technically challenging and high-risk area of neurosurgery. We aimed to describe the technical challenges of aneurysm surgery, and the scope for technological innovations to overcome these barriers from the perspective of practising neurovascular surgeons. MATERIALS AND METHODS: Consultant neurovascular surgeons and members of the British Neurovascular Group (BNVG) were electronically invited to participate in an online survey regarding surgery for both ruptured and unruptured aneurysms. The free text survey asked three questions: what do they consider to be the principal technical barriers to aneurysm clipping? What technological advances have previously contributed to improving the safety and efficacy of aneurysm clipping? What technological advances do they anticipate improving the safety and efficacy of aneurysm clipping in the future? A qualitative synthesis of responses was performed using multi-rater emergent thematic analysis. RESULTS: The most significant reported historical advances in aneurysm surgery fell into five themes: (1) optimising clip placement, (2) minimising brain retraction, (3) tissue handling, (4) visualisation and orientation, and (5) management of intraoperative rupture. The most frequently reported innovation by far was indocyanine green angiography (84% of respondents). The three most commonly cited future advances were hybrid surgical and endovascular techniques, advances in intraoperative imaging, and patient-specific simulation and planning. CONCLUSIONS: While some surgeons perceive that the rate of innovation in aneurysm clipping has been dwarfed in recent years by endovascular techniques, surgeons surveyed highlighted a broad range of future technologies that have the potential to continue to improve the safety of aneurysm surgery in the future

    Employing local cellulose fibre to reinforce the wearing course of asphalt pavement

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    The current state of road technology is incapable of alleviating the exponentially increasing traffic volume, that resulting in premature fatigue, cracks, accelerated ageing, permanent deformation, hydroplaning, as well as skidding. As a matter of fact, the wearing course on asphalt pavement is implied to use cellulose fibre as reinforcement. Cellulose fibre is derived from natural oil palm waste. This invention comprises formulation to maximise stability by using gap graded gradation and matrix of locally available sandstone aggregate. This study evaluates the optimum binder content of the mixture. Several asphalt specimens were produced by using 60/70 grade bitumen at bitumen content ranging from 5% to 7% with an increment of 0.5% by aggregate weight and with fibre at 0%, and 0.4% of aggregate weight added by dry process. Parameters evaluated were Voids in Mix, Voids Mineral Aggregate, Voids Filled with Bitumen, Specific Gravity, Resilient Modulus and Binder Drain Down Test. From the results, it suggests that optimum bitumen content with fibre inclusion is 6.5% of aggregate weight were comparatively has superlative result complying the standard. It was discovered that there was a substantial shift in the characteristics of the asphalt, resulting an improved pavement strength

    Dendritic Spine Shape Analysis: A Clustering Perspective

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    Functional properties of neurons are strongly coupled with their morphology. Changes in neuronal activity alter morphological characteristics of dendritic spines. First step towards understanding the structure-function relationship is to group spines into main spine classes reported in the literature. Shape analysis of dendritic spines can help neuroscientists understand the underlying relationships. Due to unavailability of reliable automated tools, this analysis is currently performed manually which is a time-intensive and subjective task. Several studies on spine shape classification have been reported in the literature, however, there is an on-going debate on whether distinct spine shape classes exist or whether spines should be modeled through a continuum of shape variations. Another challenge is the subjectivity and bias that is introduced due to the supervised nature of classification approaches. In this paper, we aim to address these issues by presenting a clustering perspective. In this context, clustering may serve both confirmation of known patterns and discovery of new ones. We perform cluster analysis on two-photon microscopic images of spines using morphological, shape, and appearance based features and gain insights into the spine shape analysis problem. We use histogram of oriented gradients (HOG), disjunctive normal shape models (DNSM), morphological features, and intensity profile based features for cluster analysis. We use x-means to perform cluster analysis that selects the number of clusters automatically using the Bayesian information criterion (BIC). For all features, this analysis produces 4 clusters and we observe the formation of at least one cluster consisting of spines which are difficult to be assigned to a known class. This observation supports the argument of intermediate shape types.Comment: Accepted for BioImageComputing workshop at ECCV 201

    Supportive care of patients diagnosed with high grade glioma and their carers in Australia.

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    PURPOSE: This study aimed to: determine the supportive care available for Australian patients with High Grade Glioma (HGG) and their carers; identify service gaps; and inform changes needed to implement guidelines and Optimal Care Pathways. METHODS: This cross-sectional online survey recruited multidisciplinary health professionals (HPs) who were members of the Cooperative Trials Group for Neuro-Oncology involved in management of patients diagnosed with HGG in Australian hospitals. Descriptive statistics were calculated. Fisher's exact test was used to explore differences between groups. RESULTS: 42 complete responses were received. A majority of MDT meetings were attended by a: neurosurgeon, radiation oncologist, medical oncologist, radiologist, and care coordinator. Less than 10% reported attendance by a palliative care nurse; physiotherapist; neuropsychologist; or speech therapist. Most could access referral pathways to a cancer care coordinator (76%), neuropsychologist (78%), radiation oncology nurse (77%), or psycho-oncologist (73%), palliative care (93-100%) and mental health professionals (60-85%). However, few routinely referred to an exercise physiologist (10%), rehabilitation physician (22%), dietitian (22%) or speech therapist (28%). Similarly, routine referrals to specialist mental health services were not standard practice. Nearly all HPs (94%) reported HGG patients were advised to present to their GP for pre-existing conditions/comorbidities; however, most HPs took responsibility (≤ 36% referred to GP) for social issues, mental health, symptoms, cancer complications, and treatment side-effects. CONCLUSIONS: While certain services are accessible to HGG patients nationally, improvements are needed. Psychosocial support, specialist allied health, and primary care providers are not yet routinely integrated into the care of HGG patients and their carers despite these services being considered essential in clinical practice guidelines and optimal care pathways

    A newly developed kelulut honey drink enriched with seaweed by using design of experiment approach

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    A novel functional drink, Kelulut honey enriched with seaweed (designated as KhS), was successfully developed by using design of experiment (DOE) approach in this study. A two-level-factor Full Factorial Design (FFD), 22, was employed to screen the interactions among the two major composition (Kelulut honey and seaweed) as well as to analyse the effect of these ingredients towards the sensory and proximate properties of the newly developed product. The design of experiment (DOE) and data analysis were executed by using Design- Expert Software. Two main approaches of hedonic tests, i.e., the measurement of preference and the measurement of acceptance were applied during sensory evaluation. Results indicated that amount of seaweed and honey used during the preparation of KhS did affect the moisture content and pH of the end product significantly. Sensory evaluation revealed that the overall acceptability score of the newly developed Kelulut honey enriched with seaweed drink was prefered moderately by most of the panelists and thus it could be a favourable product to be commercialised in the market

    Application of Graphene within Optoelectronic Devices and Transistors

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    Scientists are always yearning for new and exciting ways to unlock graphene's true potential. However, recent reports suggest this two-dimensional material may harbor some unique properties, making it a viable candidate for use in optoelectronic and semiconducting devices. Whereas on one hand, graphene is highly transparent due to its atomic thickness, the material does exhibit a strong interaction with photons. This has clear advantages over existing materials used in photonic devices such as Indium-based compounds. Moreover, the material can be used to 'trap' light and alter the incident wavelength, forming the basis of the plasmonic devices. We also highlight upon graphene's nonlinear optical response to an applied electric field, and the phenomenon of saturable absorption. Within the context of logical devices, graphene has no discernible band-gap. Therefore, generating one will be of utmost importance. Amongst many others, some existing methods to open this band-gap include chemical doping, deformation of the honeycomb structure, or the use of carbon nanotubes (CNTs). We shall also discuss various designs of transistors, including those which incorporate CNTs, and others which exploit the idea of quantum tunneling. A key advantage of the CNT transistor is that ballistic transport occurs throughout the CNT channel, with short channel effects being minimized. We shall also discuss recent developments of the graphene tunneling transistor, with emphasis being placed upon its operational mechanism. Finally, we provide perspective for incorporating graphene within high frequency devices, which do not require a pre-defined band-gap.Comment: Due to be published in "Current Topics in Applied Spectroscopy and the Science of Nanomaterials" - Springer (Fall 2014). (17 pages, 19 figures

    Prevalence of invasive fungal disease in hematological patients at a tertiary university hospital in Singapore

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    <p>Abstract</p> <p>Background</p> <p>The use of newer azoles as prophylaxis in hematological patients undergoing stem cell transplantation or immunosuppressive chemotherapy has been shown to decrease the risk of developing invasive fungal disease (IFD). However, the cost-effectiveness of such a strategy is dependent on the local epidemiology of IFD. We conducted an audit of hematological patients with IFD in our institution in order to derive the prevalence and types of IFD that occur locally.</p> <p>Findings</p> <p>We conducted a retrospective chart review of all hematological patients who developed possible, probable or definite IFD according to EORTC/MSG criteria in the period from Oct 2007 to Apr 2010. The prevalence of IFD was determined via correlation with institutional database records of all hematological patients treated at our institution over the same time period.</p> <p>There were 39 cases of IFD diagnosed during the study period, with 8 (20.5%) possible, 19 (48.7%) probable and 12 (30.8%) definite cases of IFD. <it>Aspergillus </it>spp. accounted for 83.9% of all probable and definite infections. There was 1 case each of <it>Rhinocladelia </it>spp., <it>Coprinopsis cinerea</it>, <it>Exserohilum </it>spp. sinusitis and <it>Rhizopus </it>spp. sinusitis. IFD occurred in 12 of 124 (9.7%) AML and 4 of 103 (3.9%) ALL patients treated at our institution respectively. There were 10 (16.1%) infections among 62 allogeneic HSCT recipients, six of whom were having concurrent graft-versus-host disease (GVHD). Five other cases occurred after allogeneic HSCT failure, following salvage chemotherapy for disease relapse. The prevalence of IFD during induction chemotherapy was 8.9% (11 of 124 cases) for AML and 1.0% (1 of 103 cases) for ALL. Fluconazole prophylaxis had been provided for 28 out of the 39 (71.8%) cases, while 4 (10.3%) were on itraconazole prophylaxis. The in-hospital mortality was 28.2% (11 of 39 cases), of which 5 (12.8%) deaths were attributed to IFD.</p> <p>Conclusions</p> <p>The burden of IFD is high in our institution, especially in allogeneic HSCT recipients and patients on induction chemotherapy for AML. A prophylactic strategy directed against invasive mould infections for local high-risk patients may be considered as the comparative costs of treatment, prolonged hospitalisation and subsequent delayed chemotherapy favours such an approach.</p

    Thermal Properties of Graphene, Carbon Nanotubes and Nanostructured Carbon Materials

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    Recent years witnessed a rapid growth of interest of scientific and engineering communities to thermal properties of materials. Carbon allotropes and derivatives occupy a unique place in terms of their ability to conduct heat. The room-temperature thermal conductivity of carbon materials span an extraordinary large range - of over five orders of magnitude - from the lowest in amorphous carbons to the highest in graphene and carbon nanotubes. I review thermal and thermoelectric properties of carbon materials focusing on recent results for graphene, carbon nanotubes and nanostructured carbon materials with different degrees of disorder. A special attention is given to the unusual size dependence of heat conduction in two-dimensional crystals and, specifically, in graphene. I also describe prospects of applications of graphene and carbon materials for thermal management of electronics.Comment: Review Paper; 37 manuscript pages; 4 figures and 2 boxe
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