7,659 research outputs found

    Calculation of losses in 2-D photonic crystal membrane waveguides using the 3-D FDTD method

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    Exploratory Study of the Association between the Severity of Idiopathic Intracranial Hypertension and Electroretinogram Photopic Negative Response Amplitude Obtained Using a Handheld Device

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    The photopic negative response (PhNR) is a negative component of the photopic flash electroretinogram that follows the b-wave and is thought to arise from the retinal ganglion cells. Reduction in its amplitude in idiopathic intracranial hypertension (IIH) has been previously documented using formal electroretinography. This study explored the use of a handheld device (RETeval, LKC technologies, Gaithersburg, MD, USA) in 72 IIH patients of varying stages and severity (and seven controls) and investigated associations between PhNR parameters and disease severity. PhNR amplitudes at 72 ms (P72) and p-ratio (ratio to b-wave peak value) differed significantly across groups, with a trend towards smaller amplitudes in those with severe IIH, defined as papilloedema with Modified Frisén Scale (MFS) ≥ 3, retinal nerve fibre layer (RNFL) ≥ 150 μm or atrophic papilloedema (p = 0.0048 and p = 0.018 for P72 and p-ratio, respectively). PhNR parameters did not correlate with MFS, RNFL thickness, standard automated perimetry mean deviation or macular ganglion cell layer volume. This study suggests that PhNR measurement using a handheld device is feasible and could potentially augment the assessment of disease severity in IIH. The clinical utility of PhNR monitoring in IIH patients requires further investigation

    Prevalence, Concordance, and Heritability of Vitreomacular Interface Abnormalities in a Twin Study

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    PURPOSE: The relative importance of genetic factors in common vitreomacular interface (VMI) abnormalities is unknown. The aim of this classical twin study is to determine the prevalence case wise concordance between monozygotic and dizygotic twin pairs, and heritability of common VMI abnormalities, including epiretinal membrane (ERM), posterior vitreous detachment (PVD), vitreomacular adhesion (VMA), vitreomacular traction (VMT), lamellar macular holes (LMHs), and full-thickness macular holes (FTMHs). METHODS: This is a single-center, cross-sectional classical twin study of 3406 TwinsUK participants over the age of 40 years who underwent spectral domain macular optical coherence tomography (SD-OCT) scans which were graded for signs of VMI abnormalities. Case wise concordance was calculated and the heritability of each VMI abnormality was estimated using OpenMx structural equation modeling. RESULTS: In this population (mean age = 62.0 years [SD = 10.4 years], range = 40–89 years) the overall prevalence of ERM was 15.6% (95% confidence interval [CI] = 14.4–16.9) and increased with age, posterior vitreous detachment affected 21.3% (20.0–22.7), and VMA was diagnosed in 11.8% (10.8–13.0). Monozygotic twins were more concordant for all traits than dizygotic twins, and age, spherical equivalent refraction (SER), and lens status-adjusted heritability was estimated at 38.9% (95% CI = 33.6–52.8) for ERM, 53.2% (95% CI = 41.8–63.2) for PVD, and 48.1% (95% CI = 33.6–58) for VMA. CONCLUSIONS: Common VMI abnormalities are heritable and therefore have an underlying genetic component. Given the sight-threatening potential of VMI abnormalities, further genetic studies, such as genomewide association studies, would be useful to identify genes and pathways implicated in their pathogenesis

    Evolution of strigolactone receptors by gradual neofunctionalization of KAI2 paralogues

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    Background: Strigolactones (SLs) are a class of plant hormones that control many aspects of plant growth. The SL signalling mechanism is homologous to that of karrikins (KARs), smoke-derived compounds that stimulate seed germination. In angiosperms, the SL receptor is an a/p hydrolase known as DWARF14 (D14); its close homologue, KARRIKIN INSENSITIVE2 (KAI2), functions as a KAR receptor, and likely recognizes an uncharacterized, endogenous signal (‘KL’). Previous phylogenetic analyses have suggested that the KAI2 lineage is ancestral in land plants, and that canonical D14-type SL receptors only arose in seed plants; this is paradoxical, however, as nonvascular plants synthesize and respond to SLs. Results: We have used a combination of phylogenetic and structural approaches to re-assess the evolution of the D14/KAI2 family in land plants. We analyzed 339 members of the D14/KAI2 family from land plants and charophyte algae. Our phylogenetic analyses show that the divergence between the eu-KAI2 lineage and the DDK (D14/DLK2/KAI2) lineage that includes D14 occurred very early in land plant evolution. We show that eu-KAI2 proteins are highly conserved, and have unique features not found in DDK proteins. Conversely, we show that DDK proteins show considerable sequence and structural variation to each other, and lack clearly definable characteristics. We use homology modelling to show that the earliest members of the DDK lineage structurally resemble KAI2, and that SL receptors in non-seed plants likely do not have D14-like structure. We also show that certain groups of DDK proteins lack the otherwise conserved MAX2-interface, and may thus function independently of MAX2, which we show is highly conserved throughout land plant evolution. Conclusions: Our results suggest D14-like structure is not required for SL perception, and that SL perception has relatively relaxed structural requirements compared to KAI2-mediated signalling. We suggest that SL perception gradually evolved by neo-functionalization within the DDK lineage, and that the transition from KAI2-like to D14-like protein may have been driven by interactions with protein partners, rather than being required for SL perception per se

    Class III obesity is a risk factor for the development of acute on chronic liver failure in patients with decompensated cirrhosis

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    BACKGROUND AND AIMS: Acute on chronic liver failure (ACLF) is a syndrome of systemic inflammation and organ failures. Obesity, also characterized by chronic inflammation, is a risk factor among patients with cirrhosis for decompensation, infection, and mortality. Our aim was to test the hypothesis that obesity predisposes to ACLF development in patients with decompensated cirrhosis. METHODS: We examined the United Network for Organ Sharing (UNOS) database, from 2005-2016, characterizing patients at wait-listing as non-obese (BMI < 30), obese class I-II (BMI 30-39.9) and obese class III (BMI≥40). ACLF was determined based on the CANONIC study definition. We used Cox proportional hazards regression to assess the association between obesity and ACLF development at liver transplantation (LT). We confirmed our findings using the Nationwide Inpatient Sample (NIS), years 2009-2013, using validated diagnostic coding algorithms to identify obesity, hepatic decompensation and ACLF. Logistic regression evaluated the association between obesity and ACLF occurrence. RESULTS: Among 387,884 with decompensated cirrhosis, 116,704 patients (30.1%) were identified as having ACLF in both databases. Multivariable modeling from the UNOS database revealed class III obesity to be an independent risk factor for ACLF at LT (HR=1.24, 95% CI 1.09-1.41, p<0.001). This finding was confirmed using the NIS (OR=1.30, 95% CI 1.25-1.35, p<0.001). Regarding specific organ failures, analysis of both registries demonstrated patients with class I-II and class III obesity had greater prevalence of renal failure. CONCLUSION: Class III obesity is a newly identified risk factor for ACLF development in patients with decompensated cirrhosis. Obese patients have a particularly higher prevalence of renal failure as a component of ACLF. These findings have important implications regarding stratifying risk and preventing the occurrence of ACLF. LAY SUMMARY: In this study, we identify that among patients with decompensated cirrhosis, class III obesity is a modifiable risk factor for the development of acute on chronic liver failure (ACLF). We further demonstrate that regarding the specific organ failures associated with ACLF, renal failure is significantly more prevalent among obese patients, particularly class III obesity. These findings underscore the importance of weight management in cirrhosis, to reduce the risk of ACLF. Patients with class III obesity should be monitored closely for the development of renal failure

    Nanoparticle-encapsulated chlorhexidine against oral bacterial biofilms

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    Background: Chlorhexidine (CHX) is a widely used antimicrobial agent in dentistry. Herein, we report the synthesis of a novel mesoporous silica nanoparticle-encapsulated pure CHX (Nano-CHX), and its mechanical profile and antimicrobial properties against oral biofilms. Methodology/Principal Findings: The release of CHX from the Nano-CHX was characterized by UV/visible absorption spectroscopy. The antimicrobial properties of Nano-CHX were evaluated in both planktonic and biofilm modes of representative oral pathogenic bacteria. The Nano-CHX demonstrated potent antibacterial effects on planktonic bacteria and mono-species biofilms at the concentrations of 50-200 mu g/mL against Streptococcus mutans, Streptococcus sobrinus, Fusobacterium nucleatum, Aggregatibacter actinomycetemcomitans and Enterococccus faecalis. Moreover, Nano-CHX effectively suppressed multi-species biofilms such as S. mutans, F. nucleatum, A. actinomycetemcomitans and Porphyromonas gingivalis up to 72 h. Conclusions/Significance: This pioneering study demonstrates the potent antibacterial effects of the Nano-CHX on oral biofilms, and it may be developed as a novel and promising anti-biofilm agent for clinical use.published_or_final_versio

    Modelling of Coupled Mass and Thermal Balances in Hall-Heroult Cells during Anode Change

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    As the most routine work practice in an aluminum reduction cell, anode change introduces substantial perturbations that adversely affect the mass and heat balance of the cell which may lead to loss of process efficiency and increased energy consumption. The literature lacks a dynamic mathematical model that describes the interactions among cell variables (e.g., electrolyte temperature and flow, anode current distribution, and cell heat loss) during and following this operation, which could otherwise be used to understand the process in greater depth and to develop changes that improve process operations and control. This paper presents a spatially-discretised dynamic model for anode replacement that integrates mass balance, thermal balance and cell voltage to describe and predict local cell variables. It was experimentally validated with an industrial cell undergoing an anode change procedure. This generic model can be applied to different cell design or process conditions by using appropriate parameters (e.g., heat transfer coefficients, conductivities, and flow patterns). The model can be used to improve existing process operations or control strategies for higher process efficiency, lower energy consumption, and lower emissions

    Determinants of adults' intention to vaccinate against pandemic swine flu

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    This article has been made available through the Brunel Open Access Publishing Fund.This article has been made available through the Brunel Open Access Publishing Fund.Background: Vaccination is one of the cornerstones of controlling an influenza pandemic. To optimise vaccination rates in the general population, ways of identifying determinants that influence decisions to have or not to have a vaccination need to be understood. Therefore, this study aimed to predict intention to have a swine influenza vaccination in an adult population in the UK. An extension of the Theory of Planned Behaviour provided the theoretical framework for the study. Methods: Three hundred and sixty two adults from the UK, who were not in vaccination priority groups, completed either an online (n = 306) or pen and paper (n = 56) questionnaire. Data were collected from 30th October 2009, just after swine flu vaccination became available in the UK, and concluded on 31st December 2009. The main outcome of interest was future swine flu vaccination intentions. Results: The extended Theory of Planned Behaviour predicted 60% of adults’ intention to have a swine flu vaccination with attitude, subjective norm, perceived control, anticipating feelings of regret (the impact of missing a vaccination opportunity), intention to have a seasonal vaccine this year, one perceived barrier: “I cannot be bothered to get a swine flu vaccination” and two perceived benefits: “vaccination decreases my chance of getting swine flu or its complications” and “if I get vaccinated for swine flu, I will decrease the frequency of having to consult my doctor,” being significant predictors of intention. Black British were less likely to intend to have a vaccination compared to Asian or White respondents. Conclusions: Theoretical frameworks which identify determinants that influence decisions to have a pandemic influenza vaccination are useful. The implications of this research are discussed with a view to maximising any future pandemic influenza vaccination uptake using theoretically-driven applications.This article is available through the Brunel Open Access Publishing Fund

    Patients with severe acute‐on‐chronic liver failure are disadvantaged by model for end‐stage liver disease‐based organ allocation policy

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    Background: Mortality for patients with acute‐on‐chronic liver failure (ACLF) may be underestimated by the model for end‐stage liver disease‐sodium (MELD‐Na) score. / Aim: To assess waitlist outcomes across varying grades of ACLF among a cohort of patients listed with a MELD‐Na score ≥35, and therefore having similar priority for liver transplantation. / Methods: We analysed the United Network for Organ Sharing (UNOS) database, years 2010‐2017. Waitlist outcomes were evaluated using Fine and Gray's competing risks regression. / Results: We identified 6342 candidates at listing with a MELD‐Na score ≥35, of whom 3122 had ACLF‐3. Extra‐hepatic organ failures were present primarily in patients with four to six organ failures. Competing risks regression revealed that candidates listed with ACLF‐3 had a significantly higher risk for 90‐day waitlist mortality (Sub‐hazard ratio (SHR) = 1.41; 95% confidence interval [CI] 1.12‐1.78) relative to patients with lower ACLF grades. Subgroup analysis of ACLF‐3 revealed that both the presence of three organ failures (SHR = 1.40, 95% CI 1.20‐1.63) or four to six organ failures at listing (SHR = 3.01; 95% CI 2.54‐3.58) was associated with increased waitlist death. Candidates with four to six organ failures also had the lowest likelihood of receiving liver transplantation (SHR = 0.61, 95% CI 0.54‐0.68). The Share 35 rule was associated with reduced 90‐day waitlist mortality among the full cohort of patients listed with ACLF‐3 and MELD‐Na score ≥35 (SHR = 0.59; 95% CI 0.49‐0.70). However, Share 35 rule implementation was not associated with reduced waitlist mortality among patients with four to six organ failures (SHR = 0.76; 95% CI 0.58‐1.02). / Conclusion: The MELD‐Na score disadvantages patients with ACLF‐3, both with and without extra‐hepatic organ failures. Incorporation of organ failures into allocation policy warrants further exploration
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