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Search Results: 1 - 10 of 134779 matches for " Sean V. Murphy "
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The Association of Hepatitis B Vaccine Supply Policy with Timing of Receipt of the First Dose of Hepatitis B Vaccination  [PDF]
Zhen Zhao, Trudy V. Murphy
Open Journal of Statistics (OJS) , 2012, DOI: 10.4236/ojs.2012.24053
Abstract: An estimated 800,000 - 1.4 million persons in the US have chronic hepatitis B virus (HBV) infection. The risk for chronic infection is greatest among young children; approximately 90% of infants will remain chronically infected with HBV. Approximately 25% of those who become chronically infected during childhood die prematurely from cirrhosis or liver cancer. Hepatitis B vaccination is the most effective measure to prevent HBV infection and its consequences. In 2006, 29 US states had Hepatitis B Vaccine Supply (HBVS) policy which either supplies hepatitis B vaccine at no cost to all providers for all children or provides hepatitis B vaccine to delivery hospitals-only free of charge for all infants; other 21 US states and the District of Columbia did not have. 17,636 infants born in 2006 obtained from 2007-2009 National Immunization Survey (NIS) were analyzed with survival analysis procedures of Kaplan-Meier estimate and Cox proportional hazards model for complex sample survey to evaluate the association between state HBVS policy and the timing of infant age in days to receipt of hepatitis B vaccination. State HBVS policy is associated with infant age in days from birth to receipt of the first dose of hepatitis B vaccine (P < 0.01), and to completion of the 3-dose hepatitis B vaccine series (P < 0.01). Receipt of the first dose of hepatitis B vaccine occurred 31% earlier among infants residing in states with HBVS policy than among infants residing in states without (adjusted hazards ratio 1.31, 95%CI (1.23, 1.39)). Completion of the 3-dose hepatitis B vaccine series were 12% sooner among infants living in states with HBVS policy than among infants living in states without (adjusted hazards ratio 1.12, 95%CI (1.06, 1.18)). State HBVS policy may help overcome barriers to timely delivery of hepatitis B vaccines to infants.
Competition between extinction and enhancement in surface enhanced Raman spectroscopy
Thomas van Dijk,Sean T. Sivapalan,Brent M. DeVetter,Timothy K. Yang,Matthew V. Schulmerich,Catherine J. Murphy,Rohit Bhargava,P. Scott Carney
Physics , 2013, DOI: 10.1021/jz4005043
Abstract: Conjugated metallic nanoparticles are a promising means to achieve ultrasensitive and multiplexed sensing in intact three-dimensional samples, especially for biological applications, via surface enhanced Raman scattering (SERS). We show that enhancement and extinction are linked and compete in a collection of metallic nanoparticles. Counterintuitively, the Raman signal vanishes when nanoparticles are excited at their plasmon resonance, while increasing nanoparticle concentrations at off-resonance excitation sometimes leads to decreased signal. We develop an effective medium theory that explains both phenomena. Optimal choices of excitation wavelength, individual particle enhancement factor and concentrations are indicated.
What Horses and Humans See: A Comparative Review
Jack Murphy,Carol Hall,Sean Arkins
International Journal of Zoology , 2009, DOI: 10.1155/2009/721798
Abstract: Adaptations of the mammalian eye have tailored each to its own particular ecological niche. On the one hand, it would appear that the horse is best served by a system that can keep “half an eye” on everything, while the human benefits from focussing on more specific aspects of the visual array. By adapting a range of techniques, originally used to assess human visual ability, it has been possible to compare the human visual experience with that of the horse. In general, the results of the majority of these comparative studies indicate that the visual capabilities of the horse are broadly inferior to the human equivalents in acuity, accommodation, and colour vision. However, both the horse and human abilities to judge distance and depth perception may be quite comparable while equine vision is certainly superior to that of human's under scotopic conditions. Individual variation in visual ability, which is routinely taken for granted in humans, is also likely to occur in the horse. Such variation would undoubtedly affect equine performance, particularly in terms of expectation of athletic competitive outcomes in modern equitation. In addition to such considerations as conformation and athletic ability, a detailed assessment of the visual ability might contribute to a more accurate prediction of future performance characteristics in the horse. Although further investigation is required in order to appreciate fully both the capabilities and limitations of the equine visual system, the information currently available should now be considered and applied more rigorously both in the design of the equine environment and in the implementation of contemporary equine training methods. This need is the greatest in areas of equestrian sport where the outcomes of either or both equine and human visual judgements can be critical, the cost of failure often high and occasionally results in fatal consequences for both parties of the horse-human dyad.
Human Amnion Epithelial Cells Induced to Express Functional Cystic Fibrosis Transmembrane Conductance Regulator
Sean V. Murphy, Rebecca Lim, Philip Heraud, Marian Cholewa, Mark Le Gros, Martin D. de Jonge, Daryl L. Howard, David Paterson, Courtney McDonald, Anthony Atala, Graham Jenkin, Euan M. Wallace
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0046533
Abstract: Cystic fibrosis, an autosomal recessive disorder caused by a mutation in a gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR), remains a leading cause of childhood respiratory morbidity and mortality. The respiratory consequences of cystic fibrosis include the generation of thick, tenacious mucus that impairs lung clearance, predisposing the individual to repeated and persistent infections, progressive lung damage and shortened lifespan. Currently there is no cure for cystic fibrosis. With this in mind, we investigated the ability of human amnion epithelial cells (hAECs) to express functional CFTR. We found that hAECs formed 3-dimensional structures and expressed the CFTR gene and protein after culture in Small Airway Growth Medium (SAGM). We also observed a polarized CFTR distribution on the membrane of hAECs cultured in SAGM, similar to that observed in polarized airway cells in vivo. Further, hAECs induced to express CFTR possessed functional iodide/chloride (I?/Cl?) ion channels that were inhibited by the CFTR-inhibitor CFTR-172, indicating the presence of functional CFTR ion channels. These data suggest that hAECs may be a promising source for the development of a cellular therapy for cystic fibrosis.
A longitudinal qualitative study examining the factors impacting on the ability of persons with T1DM to assimilate the Dose Adjustment for Normal Eating (DAFNE) principles into daily living and how these factors change over time
Dympna Casey, Kathy Murphy, Julia Lawton, Florence White, Sean Dineen
BMC Public Health , 2011, DOI: 10.1186/1471-2458-11-672
Abstract: This is a longitudinal descriptive qualitative study. Interviews were undertaken with 40 participants who had attended DAFNE in one of 5 study sites across the Island of Ireland, at 6 weeks, 6 and 12 months after completion of the programme. The interviews lasted from 30 to 60 minutes and were transcribed verbatim. Data were analysed in three ways, a within time analysis, a cross sectional analysis for each participant and a thematic analysis which focused on examining changes over timeFour themes that influenced participants' ability to assimilate DAFNE into their daily lives over time were identified. These were: embedded knowledge, continued responsive support, enduring motivation and being empowered. Support at the 6 month period was found to be crucial to continued motivation.Understanding the factors that influence people's ability to assimilate DAFNE principles over time into their daily lives can help health professionals give focused responsive support that helps people with diabetes become more empowered. Understanding that continued support matters, particularly around 6 months, is important as health professionals can influence good management by providing appropriate support and enhancing motivation.ISRCTN79759174In the island of Ireland there is an estimated prevalence of diabetes of between 5-5.8% [1]. In the context of the Republic of Ireland the Diabetes Federation of Ireland estimates that approximately 12,000 people have Type 1 Diabetes Mellitus (T1DM). Self management skills are essential if persons with type 1 diabetes are to manage their condition effectively [2,3]. One way of developing these skills is through participation in a structured education programme (SEP) [4]. Currently in Ireland the Dose Adjustment for Normal Eating (DAFNE) SEP is being delivered to clients with T1DM, as part of a large 5 year multi-centred randomised controlled trial [5] examining the implementation and evaluation of the SEP and to develop a new model of ongoing c
Automatic classification of time-variable X-ray sources
Kitty K. Lo,Sean Farrell,Tara Murphy,B. M. Gaensler
Physics , 2014, DOI: 10.1088/0004-637X/786/1/20
Abstract: To maximize the discovery potential of future synoptic surveys, especially in the field of transient science, it will be necessary to use automatic classification to identify some of the astronomical sources. The data mining technique of supervised classification is suitable for this problem. Here, we present a supervised learning method to automatically classify variable X-ray sources in the second \textit{XMM-Newton} serendipitous source catalog (2XMMi-DR2). Random Forest is our classifier of choice since it is one of the most accurate learning algorithms available. Our training set consists of 873 variable sources and their features are derived from time series, spectra, and other multi-wavelength contextual information. The 10-fold cross validation accuracy of the training data is ${\sim}$97% on a seven-class data set. We applied the trained classification model to 411 unknown variable 2XMM sources to produce a probabilistically classified catalog. Using the classification margin and the Random Forest derived outlier measure, we identified 12 anomalous sources, of which, 2XMM J180658.7$-$500250 appears to be the most unusual source in the sample. Its X-ray spectra is suggestive of a ULX but its variability makes it highly unusual. Machine-learned classification and anomaly detection will facilitate scientific discoveries in the era of all-sky surveys.
Autoclassification of the Variable 3XMM Sources Using the Random Forest Machine Learning Algorithm
Sean A. Farrell,Tara Murphy,Kitty K. Lo
Physics , 2015,
Abstract: In the current era of large surveys and massive data sets, autoclassification of astrophysical sources using intelligent algorithms is becoming increasingly important. In this paper we present the catalog of variable sources in the Third XMM-Newton Serendipitous Source catalog (3XMM) autoclassified using the Random Forest machine learning algorithm. We used a sample of manually classified variable sources from the second data release of the XMM-Newton catalogs (2XMMi-DR2) to train the classifier, obtaining an accuracy of ~92%. We also evaluated the effectiveness of identifying spurious detections using a sample of spurious sources, achieving an accuracy of ~95%. Manual investigation of a random sample of classified sources confirmed these accuracy levels and showed that the Random Forest machine learning algorithm is highly effective at automatically classifying 3XMM sources. Here we present the catalog of classified 3XMM variable sources. We also present three previously unidentified unusual sources that were flagged as outlier sources by the algorithm: a new candidate supergiant fast X-ray transient, a 400 s X-ray pulsar, and an eclipsing 5 hr binary system coincident with a known Cepheid.
External Quality Assurance of Malaria Nucleic Acid Testing for Clinical Trials and Eradication Surveillance
Sean C. Murphy, Cornelus C. Hermsen, Alexander D. Douglas, Nick J. Edwards, Ines Petersen, Gary A. Fahle, Matthew Adams, Andrea A. Berry, Zachary P. Billman, Sarah C. Gilbert, Matthew B. Laurens, Odile Leroy, Kristen E. Lyke, Christopher V. Plowe, Annette M. Seilie, Kathleen A. Strauss, Karina Teelen, Adrian V. S. Hill, Robert W. Sauerwein
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0097398
Abstract: Nucleic acid testing (NAT) for malaria parasites is an increasingly recommended diagnostic endpoint in clinical trials of vaccine and drug candidates and is also important in surveillance of malaria control and elimination efforts. A variety of reported NAT assays have been described, yet no formal external quality assurance (EQA) program provides validation for the assays in use. Here, we report results of an EQA exercise for malaria NAT assays. Among five centers conducting controlled human malaria infection trials, all centers achieved 100% specificity and demonstrated limits of detection consistent with each laboratory's pre-stated expectations. Quantitative bias of reported results compared to expected results was generally <0.5 log10 parasites/mL except for one laboratory where the EQA effort identified likely reasons for a general quantitative shift. The within-laboratory variation for all assays was low at <10% coefficient of variation across a range of parasite densities. Based on this study, we propose to create a Molecular Malaria Quality Assessment program that fulfills the need for EQA of malaria NAT assays worldwide.
Targeting 3-Phosphoinoside-Dependent Kinase-1 to Inhibit Insulin-Like Growth Factor-I Induced AKT and p70 S6 Kinase Activation in Breast Cancer Cells
Sangita M. Baxi, Wei Tan, Sean T. Murphy, Tod Smeal, Min-Jean Yin
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0048402
Abstract: Binding of IGF to IGF-IR activates PI3K to generate PIP3 which in turn recruits and activates proteins that contain a pleckstrin homology (PH) domain, including AKT and PDK1. PDK1 is highly expressed in breast tumor samples and breast cancer cell lines. Here we demonstrate that targeting PDK1 with the potent and selective PDK1 inhibitor PF-5177624 in the IGF-PI3K pathway blocks breast cancer cell proliferation and transformation. Breast cancer cell lines MCF7 and T47D, representing the luminal ER positive subtype and harboring PIK3CA mutations, were most responsive to IGF-I induction resulting in upregulated AKT and p70S6K phosphorylation via PDK1 activation. PF-5177624 downregulated AKT and p70S6K phosphorylation, blocked cell cycle progression, and decreased cell proliferation and transformation to block IGFR-I induced activation in breast cancer cells. These results may provide insight into clinical strategies for developing an IGFR-I inhibitor and/or a PDK1 inhibitor in luminal breast cancer patients.
Erythrocyte G Protein as a Novel Target for Malarial Chemotherapy
Sean C Murphy,Travis Harrison,Heidi E Hamm,Jon W Lomasney,Narla Mohandas,Kasturi Haldar
PLOS Medicine , 2006, DOI: 10.1371/journal.pmed.0030528
Abstract: Background Malaria remains a serious health problem because resistance develops to all currently used drugs when their parasite targets mutate. Novel antimalarial drug targets are urgently needed to reduce global morbidity and mortality. Our prior results suggested that inhibiting erythrocyte Gs signaling blocked invasion by the human malaria parasite Plasmodium falciparum. Methods and Findings We investigated the erythrocyte guanine nucleotide regulatory protein Gs as a novel antimalarial target. Erythrocyte “ghosts” loaded with a Gs peptide designed to block Gs interaction with its receptors, were blocked in β-adrenergic agonist-induced signaling. This finding directly demonstrates that erythrocyte Gs is functional and that propranolol, an antagonist of G protein–coupled β-adrenergic receptors, dampens Gs activity in erythrocytes. We subsequently used the ghost system to directly link inhibition of host Gs to parasite entry. In addition, we discovered that ghosts loaded with the peptide were inhibited in intracellular parasite maturation. Propranolol also inhibited blood-stage parasite growth, as did other β2-antagonists. β-blocker growth inhibition appeared to be due to delay in the terminal schizont stage. When used in combination with existing antimalarials in cell culture, propranolol reduced the 50% and 90% inhibitory concentrations for existing drugs against P. falciparum by 5- to 10-fold and was also effective in reducing drug dose in animal models of infection. Conclusions Together these data establish that, in addition to invasion, erythrocyte G protein signaling is needed for intracellular parasite proliferation and thus may present a novel antimalarial target. The results provide proof of the concept that erythrocyte Gs antagonism offers a novel strategy to fight infection and that it has potential to be used to develop combination therapies with existing antimalarials.
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