2,391 research outputs found

    Prediction of far-field acoustic emissions from cavitation clouds during shock wave lithotripsy for development of a clinical device

    No full text
    This study presents the key simulation and decision stage of a multi-disciplinary project to develop a hospital device for monitoring the effectiveness of kidney stone fragmentation by shock wave lithotripsy (SWL). The device analyses, in real time, the pressure fields detected by sensors placed on the patient's torso, fields generated by the interaction of the incident shock wave, cavitation, kidney stone and soft tissue. Earlier free-Lagrange simulations of those interactions were restricted (by limited computational resources) to computational domains within a few centimetres of the stone. Later studies estimated the far-field pressures generated when those interactions involved only single bubbles. This study extends the free-Lagrange method to quantify the bubble–bubble interaction as a function of their separation. This, in turn, allowed identification of the validity of using a model of non-interacting bubbles to obtain estimations of the far-field pressures from 1000 bubbles distributed within the focus of the SWL field. Up to this point in the multi-disciplinary project, the design of the clinical device had been led by the simulations. This study records the decision point when the project's direction had to be led by far more costly clinical trials instead of the relatively inexpensive simulations. <br/

    Longer-term Baerveldt to Trabectome glaucoma surgery comparison using propensity score matching

    Get PDF
    Purpose: To apply propensity score matching to compare Baerveldt glaucoma drainage implant (BGI) to Trabectome-mediated ab interno trabeculectomy (AIT). Recent data suggests that AIT can produce results similar to BGI which is traditionally reserved for more severe glaucoma. Methods: BGI and AIT patients with at least 1 year of follow-up were included. The primary outcome measures were intraocular pressure (IOP), number of glaucoma medications, and a Glaucoma Index (GI) score. GI reflected glaucoma severity based on visual field, the number of preoperative medications, and preoperative IOP. Score matching used a genetic algorithm consisting of age, gender, type of glaucoma, concurrent phacoemulsification, baseline number of medications, and baseline IOP. Patients with neovascular glaucoma, with prior glaucoma surgery, or without a close match were excluded. Results: Of 353 patients, 30 AIT patients were matched to 29 BGI patients. Baseline characteristics including, IOP, the number of glaucoma medications, type of glaucoma, the degree of VF loss and GI were not significantly different between AIT and BGI. BGI had a preoperative IOP of 21.6 ± 6.3 mmHg compared to 21.5 ± 7.4 for AIT on 2.8 ± 1.1 medications and 2.5 ± 2.3 respectively. At 30 months, the mean IOP was 15.0 ± 3.9 mmHg for AIT versus 15.0 ± 5.7 mmHg for BGI (p > 0.05), while the number of drops was 1.5 ± 1.3 for AIT (change: p = 0.001) versus 2.4 ± 1.2 for BGI (change: p = 0.17; AIT vs BGI: 0.007). Success, defined as IOP  0.05) and 50% versus 52% at 2.5 years. Conclusions: A propensity score matched comparison of AIT and BGI demonstrated a similar IOP reduction through 1 year. AIT required fewer medications

    Exact modelling of generalised defect modes in photonic crystal structures

    Full text link
    An exact theory for modelling modes of generalised defects in 2D photonic crystals (PCs) with a genuinely infinite cladding is presented. The approach builds on our fictitious source superposition method for simple defects and permits an elegant extension allowing the modelling of arbitrary defects. Numerical results that demonstrate the accuracy and efficiency of the extended method are presented. We also use the method to study the evolution of the mode generated by varying the refractive index of a single defect cylinder and find significant differences between the behaviour of defects in rod-type and hole-type PCs. © 2007 Elsevier B.V. All rights reserved

    Pneumothorax, pneumomediastinum and subcutaneous emphysema following closed percutaneous pleural biopsy: a case report

    Get PDF
    Minimally invasive investigations, such as pleural fluid cytological assessment and closed percutaneous pleural biopsy, are often performed first in the investigation of suspected malignant pleural effusions. Malignant pleural effusions can be diagnosed with pleural fluid cytology alone in most cases; however, closed pleural biopsy is performed to increase the diagnostic yield when pleural fluid cytology is negative. This additional yield is at the expense of increased complication rates. We report a 64-year old man with a negative pleural fluid cytology but suspected malignant pleural effusion who underwent a closed pleural biopsy, which was complicated by pneumothorax, pneumomediastinum and severe subcutaneous emphysema. Pulmonary laceration by the pleural biopsy needle is the most likely aetiology of these complications. Our case report highlights an infrequent but significant complication of closed percutaneous pleural biopsy

    NLRP3 inflammasome activation by mycobacterial ESAT-6 and dsRNA in intraocular tuberculosis

    Get PDF
    The molecular basis of intraocular tuberculosis (TB) is not well understood. In this study, we investigated the role of two constituents of viable Mycobacterium tuberculosis - Early Secreted Antigenic Target-6 (ESAT-6), and mycobacterial RNA- in inflammasome activation in the retinal pigment epithelium (RPE) - a key site of inflammation in intraocular TB. We found that ESAT-6 induced caspase-1 activation and inflammasome priming in mouse RPE cells, significantly more in wild-type than in Tlr2/3/4/7/9-/-, Myd88-/- and Nlrp3-/- RPE cells. Sub-retinal ESAT-6 injection resulted in greater RPE degeneration in wild-type than Nlrp3-/- mice. In human ocular TB tissue sections, NLRP3 staining was noted in retina as well as RPE. Mycobacterial RNA, specifically its double stranded component, also induced caspase-1 activation, and the double stranded RNA was immunolocalized to human ocular TB sections. Our observations suggest that inflammasome activation in RPE by viable M. tuberculosis could potentially contribute to human intraocular TB

    <i>Lrig1</i> expression identifies airway basal cells with high proliferative capacity and restricts lung squamous cell carcinoma growth

    Get PDF
    Lung squamous cell carcinoma (LUSC) accounts for a significant proportion of cancer deaths worldwide, and is preceded by the appearance of progressively disorganised pre-invasive lesions in the airway epithelium. Yet the biological mechanisms underlying progression of pre-invasive lesions into invasive LUSC are not fully understood. LRIG1 is downregulated in pre-invasive airway lesions and invasive LUSC tumours and this correlates with decreased lung cancer patient survival.Using an Lrig1 knock-in reporter mouse and human airway epithelial cells collected at bronchoscopy, we show that during homeostasis LRIG1 is heterogeneously expressed in the airway epithelium. In basal airway epithelial cells, the suspected cell of origin of LUSC, LRIG1 identifies a subpopulation of progenitor cells with higher in vitro proliferative and self-renewal potential in both the mouse and human. Using the N-nitroso-tris-chloroethylurea (NTCU)-induced murine model of LUSC, we find that Lrig1 loss-of-function leads to abnormally high cell proliferation during the earliest stages of pre-invasive disease and to the formation of significantly larger invasive tumours, suggesting accelerated disease progression.Together, our findings identify LRIG1 as a marker of basal airway progenitor cells with high proliferative potential and as a regulator of pre-invasive lung cancer progression. This work highlights the clinical relevance of LRIG1 and the potential of the NTCU-induced LUSC model for functional assessment of candidate tumour suppressors and oncogenes

    Liquid-infiltrated photonic crystals - enhanced light-matter interactions for lab-on-a-chip applications

    Full text link
    Optical techniques are finding widespread use in analytical chemistry for chemical and bio-chemical analysis. During the past decade, there has been an increasing emphasis on miniaturization of chemical analysis systems and naturally this has stimulated a large effort in integrating microfluidics and optics in lab-on-a-chip microsystems. This development is partly defining the emerging field of optofluidics. Scaling analysis and experiments have demonstrated the advantage of micro-scale devices over their macroscopic counterparts for a number of chemical applications. However, from an optical point of view, miniaturized devices suffer dramatically from the reduced optical path compared to macroscale experiments, e.g. in a cuvette. Obviously, the reduced optical path complicates the application of optical techniques in lab-on-a-chip systems. In this paper we theoretically discuss how a strongly dispersive photonic crystal environment may be used to enhance the light-matter interactions, thus potentially compensating for the reduced optical path in lab-on-a-chip systems. Combining electromagnetic perturbation theory with full-wave electromagnetic simulations we address the prospects for achieving slow-light enhancement of Beer-Lambert-Bouguer absorption, photonic band-gap based refractometry, and high-Q cavity sensing.Comment: Invited paper accepted for the "Optofluidics" special issue to appear in Microfluidics and Nanofluidics (ed. Prof. David Erickson). 11 pages including 8 figure

    The Parasitoid, Verticia fasciventris Causes Morphological and Behavioral Changes in Infected Soldiers of the Fungus-Growing Termite, Macrotermes carbonarius

    Get PDF
    The larval parasitoid Verticia fasciventris Malloch (Diptera: Calliphoridae) develops in the head of soldiers of the fungus-growing termite Macrotermes carbonarius (Hagen) (Isoptera: Termitidae). Morphological and behavioral changes in the host were evaluated and the termite castes and stages that were parasitized were identified. The larval emergence process is also described and possible mechanisms for the parasitoid fly's entry into the host body are discussed based on qualitative observations. Only a single larva per host was found. The mature larva pupated outside the host's body by exiting between the abdominal cerci. Parasitized soldiers possess a short and square-shaped head capsule, a pair of notably short mandibles, and a pair of 18-segmented antennae. Although parasitized soldiers were statistically less aggressive than healthy soldiers (P < 0.05), they expressed varying levels of aggression. Both minor and major soldiers can be parasitized and based on evidence from presoldiers, parasitization may begin during the precursor stages of soldiers. However, the stage at which parasitism first occurs has not been determined

    Incidence of rotavirus gastroenteritis by age in African, Asian and European children: Relevance for timing of rotavirus vaccination

    Get PDF
    © 2016 The Author(s). Published with license by Taylor & Francis. © GSK Biologicals SA.Variability in rotavirus gastroenteritis (RVGE) epidemiology can influence the optimal vaccination schedule. We evaluated regional trends in the age of RVGE episodes in low- to middle- versus high-income countries in three continents. We undertook a post-hoc analysis based on efficacy trials of a human rotavirus vaccine (HRV; Rotarix™, GSK Vaccines), in which 1348, 1641, and 5250 healthy infants received a placebo in Europe (NCT00140686), Africa (NCT00241644), and Asia (NCT00197210, NCT00329745). Incidence of any/severe RVGE by age at onset was evaluated by active surveillance over the first two years of life. Severity of RVGE episodes was assessed using the Vesikari-scale. The incidence of any RVGE in Africa was higher than in Europe during the first year of life (≤2.78% vs. ≤2.03% per month), but much lower during the second one (≤0.86% versus ≤2.00% per month). The incidence of severe RVGE in Africa was slightly lower than in Europe during the first year of life. Nevertheless, temporal profiles for the incidence of severe RVGE in Africa and Europe during the first (≤1.00% and ≤1.23% per month) and second (≤0.53% and ≤1.13% per month) years of life were similar to those of any RVGE. Any/severe RVGE incidences peaked at younger ages in Africa vs. Europe. In high-income Asian regions, severe RVGE incidence (≤0.31% per month) remained low during the study. The burden of any RVGE was higher earlier in life in children from low- to middle- compared with high-income countries. Differing rotavirus vaccine schedules are likely warranted to maximize protection in different settings
    corecore