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1.
Food Microbiol ; 95: 103674, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33397608

RESUMO

Recurring outbreaks linked to Escherichia coli O157:H7-contaminated lettuce and Salmonella enterica-contaminated sprouts highlight the need for improved food safety measures. The aim of this study was to determine the ability of a bio-based antimicrobial extract prepared from switchgrass, a dedicated energy crop, to reduce E. coli O157:H7 and S. Typhimurium populations on Formica coupons, a model food-contact surface. Overnight cultures of ~7 log CFU/mL E. coli O157:H7 and S. Typhimurium, air-dried on Formica coupons were treated with 0.625% NaClO, 70% ethanol, sterile water or different batches of switchgrass extractives (SE1, SE2, and SE3) for up to 30 min. E. coli O157:H7 was reduced by 4.43 log CFU/mL after 1 min by SE3, and to non-detectable levels after 1 min by all other treatments. Populations of S. Typhimurium LT2 (15-min drying) were reduced by 3.30 log CFU/mL with 70% ethanol, 5.38 log CFU/mL with SE1, and to non-detectable levels with 0.625% NaClO after 1 min, while S. Typhimurium ATCC 23564 (1-h drying) was non-detectable after 1 min by all treatments. Under soiled conditions, 10-min treatment with SE1 and 70% ethanol reduced both bacteria to non-detectable levels. Studies with concentrated switchgrass extractives combined with various other natural disinfectants or in hurdle approaches warrant further investigation.


Assuntos
Desinfetantes/farmacologia , Escherichia coli O157/efeitos dos fármacos , Panicum/química , Extratos Vegetais/farmacologia , Salmonella typhimurium/efeitos dos fármacos , Contagem de Colônia Microbiana , Escherichia coli O157/crescimento & desenvolvimento , Papel , Salmonella typhimurium/crescimento & desenvolvimento
2.
Phytother Res ; 32(6): 1064-1072, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29464849

RESUMO

The traditional practice of eating the flowers of Clitoria ternatea L. or drinking their infusion as herbal tea in some of the Asian countries is believed to promote a younger skin complexion and defend against skin aging. This study was conducted to investigate the protective effect of C. ternatea flower water extract (CTW) against hydrogen peroxide-induced cytotoxicity and ultraviolet (UV)-induced mitochondrial DNA (mtDNA) damage in human keratinocytes. The protective effect against hydrogen peroxide-induced cytotoxicity was determined by 3-(4, 5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay, and mtDNA damage induced by UV was determined by polymerase chain reaction. Preincubation of HaCaT with 100, 250, and 500 µg/ml CTW reduced cytotoxicity effects of H2 O2 compared with control (H2 O2 alone). CTW also significantly reduced mtDNA damage in UV-exposed HaCaT (p < .05). CTW was chemically-characterized using high resolution liquid chromatography-mass spectrometry. The main compounds detected were assigned as anthocyanins derived from delphinidin, including polyacylated ternatins, and flavonol glycosides derived from quercetin and kaempferol. These results demonstrated the protective effects of C. ternatea flower extracts that contain polyacylated anthocyanins and flavonol glycosides as major constituents, against H2 O2 and UV-induced oxidative stress on skin cells, and may provide some explanation for the putative traditional and cosmetic uses of C. ternatea flower against skin aging.


Assuntos
Antioxidantes/uso terapêutico , Clitoria/química , DNA Mitocondrial/efeitos adversos , Peróxido de Hidrogênio/metabolismo , Queratinócitos/efeitos dos fármacos , Extratos Vegetais/química , Antioxidantes/farmacologia , Humanos , Peróxido de Hidrogênio/análise
3.
Br J Dermatol ; 175 Suppl 2: 26-29, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27667312

RESUMO

Oxidative stress is the resultant damage due to redox imbalances (increase in destructive free radicals [reactive oxygen species (ROS)] and reduction in antioxidant protection/pathways) and is linked to ageing in many tissues including skin. In ageing skin there are bioenergetic differences between keratinocytes and fibroblasts which provide a potential ageing biomarker. The differences in skin bioenergy are part of the mitochondrial theory of ageing which remains one of the most widely accepted ageing theories describing subsequent increasing free radical generation. Mitochondria are the major source of cellular oxidative stress and form part of the vicious cycle theory of ageing. External and internal sources of oxidative stress include UVR/IR, pollution (environment), lifestyle (exercise and diet), alcohol and smoking all of which may potentially impact on skin although many exogenous actives and endogenous antioxidant defence systems have been described to help abrogate the increased stress. This also links to differences in skin cell types in terms of the UVR action spectrum for nuclear and mitochondrial DNA damage (the latter a previously described UVR biomarker in skin). Recent work associates bioenergy production and oxidative stress with pigment production thereby providing another additional potential avenue for targeted anti-ageing intervention in skin. This new data supporting the detrimental effects of the numerous wavelengths of UVR may aid in the development of cosmetic/sunscreen design to reduce the effects of photoageing. Recently, complex II of the mitochondrial electron transport chain appears to be more important than previously thought in the generation of free radicals (suggested predominantly by non-human studies). We investigated the relationship between complex II and ageing using human skin as a model tissue. The rate of complex II activity per unit of mitochondria was determined in fibroblasts and keratinocytes cultured from skin covering a wide age range. Complex II activity significantly decreased with age in fibroblasts (P = 0·015), but not in keratinocytes. This was associated with a significant decline in transcript expression (P = 0·008 and P = 0·001) and protein levels (P = 0·0006 and P = 0·005) of the SDHA and SDHB catalytic subunits of complex II respectively. In addition there was a significant decrease in complex II activity with age (P = 0·029) that was specific to senescent skin cells, our study being the first to investigate these differences with senescence and skin age. There was no decrease in complex IV activity with increasing age, suggesting possible locality to complex II. Our study provides a future potential biomarker for monitoring the progression of skin ageing.

4.
Environmetrics ; 26(5): 327-338, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27563267

RESUMO

Scientists need appropriate spatial-statistical models to account for the unique features of stream network data. Recent advances provide a growing methodological toolbox for modelling these data, but general-purpose statistical software has only recently emerged, with little information about when to use different approaches. We implemented a simulation study to evaluate and validate geostatistical models that use continuous distances, and penalised spline models that use a finite discrete approximation for stream networks. Data were simulated from the geostatistical model, with performance measured by empirical prediction and fixed effects estimation. We found that both models were comparable in terms of squared error, with a slight advantage for the geostatistical models. Generally, both methods were unbiased and had valid confidence intervals. The most marked differences were found for confidence intervals on fixed-effect parameter estimates, where, for small sample sizes, the spline models underestimated variance. However, the penalised spline models were always more computationally efficient, which may be important for real-time prediction and estimation. Thus, decisions about which method to use must be influenced by the size and format of the data set, in addition to the characteristics of the environmental process and the modelling goals. ©2015 The Authors. Environmetrics published by John Wiley & Sons, Ltd.

5.
Environmetrics ; 26(6): 431-441, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26900339

RESUMO

Fitting statistical models to spatiotemporal data requires finding the right balance between imposing smoothness and following the data. In the context of P-splines, we propose a Bayesian framework for choosing the smoothing parameter, which allows the construction of fully automatic data-driven methods for fitting flexible models to spatiotemporal data. An implementation, which is highly computationally efficient and exploits the sparsity of the design and penalty matrices, is proposed. The findings are illustrated using a simulation study and two examples, all concerned with the modelling of contaminants in groundwater. This suggests that the proposed strategy is more stable that competing methods based on the use of criteria such as generalised cross-validation and Akaike's Information Criterion. © 2015 The Authors. Environmetrics Published by John Wiley Sons Ltd.

6.
Int J Cosmet Sci ; 37 Suppl 2: 1-8, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26574299

RESUMO

Oxidative stress is the resultant damage that arises due to redox imbalances, more specifically an increase in destructive free radicals and reduction in protection from antioxidants and the antioxidant defence pathways. Oxidation of lipids by reactive oxygen species (ROS) can damage cellular structures and result in premature cell death. At low levels, ROS-induced oxidative stress can be prevented through the action of antioxidants, however, when ROS are present in excess, inflammation and cytotoxicity eventually results leading to cellular oxidative stress damage. Increasing evidence for the role of oxidative stress in various diseases including neurological, dermatological, and cardiovascular diseases is now emerging. Mitochondria are the principal source (90%) of ROS in the cell, with superoxide radicals being generated when molecular oxygen is combined with free electrons. Given the key role of mitochondria in the generation of cellular oxidative stress it is worth considering this organelle and the process in more detail and to provide methods of intervention.


Assuntos
Envelhecimento/metabolismo , Estética , Nível de Saúde , Estilo de Vida , Estresse Oxidativo , Humanos , Mitocôndrias/metabolismo , Espécies Reativas de Oxigênio/metabolismo
7.
Parasitology ; 140(2): 237-46, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23036286

RESUMO

Lyme borreliosis (LB) is the most common arthropod-borne disease of humans in the Northern hemisphere. In Europe, the causative agent, Borrelia burgdorferi sensu lato complex, is principally vectored by Ixodes ricinus ticks. The aim of this study was to identify environmental factors influencing questing I. ricinus nymph abundance and B. burgdorferi s.l. infection in questing nymphs using a large-scale survey across Scotland. Ticks, host dung and vegetation were surveyed at 25 woodland sites, and climatic variables from a Geographical Information System (GIS) were extracted for each site. A total of 2397 10 m2 transect surveys were conducted and 13 250 I. ricinus nymphs counted. Questing nymphs were assayed for B. burgdorferi s.l. and the average infection prevalence was 5·6% (range 0·8-13·9%). More questing nymphs and higher incidence of B. burgdorferi s.l. infection were found in areas with higher deer abundance and in mixed/deciduous compared to coniferous forests, as well as weaker correlations with season, altitude, rainfall and ground vegetation. No correlation was found between nymph abundance and infection prevalence within the ranges encountered. An understanding of the environmental conditions associated with tick abundance and pathogen prevalence may be used to reduce risk of exposure and to predict future pathogen prevalence and distributions under environmental changes.


Assuntos
Borrelia burgdorferi/fisiologia , Meio Ambiente , Ixodes/microbiologia , Ixodes/fisiologia , Altitude , Animais , Cervos/parasitologia , Cervos/fisiologia , Incidência , Doença de Lyme/epidemiologia , Doença de Lyme/parasitologia , Ninfa/microbiologia , Densidade Demográfica , Prevalência , Chuva , Fatores de Risco , Escócia , Estações do Ano , Árvores/fisiologia
8.
Parasitology ; 139(4): 419-23, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22216951

RESUMO

Although widely used, the term repellency needs to be employed with care when applied to ticks and other periodic or permanent ectoparasites. Repellency has classically been used to describe the effects of a substance that causes a flying arthropod to make oriented movements away from its source. However, for crawling arthropods such as ticks, the term commonly subsumes a range of effects that include arthropod irritation and consequent avoiding or leaving the host, failing to attach, to bite, or to feed. The objective of the present article is to highlight the need for clarity, to propose consensus descriptions and methods for the evaluation of various effects on ticks caused by chemical substances.


Assuntos
Repelentes de Insetos/farmacologia , Repelentes de Insetos/normas , Infestações por Carrapato/prevenção & controle , Carrapatos/efeitos dos fármacos , Medicina Veterinária/normas , Animais , Infestações por Carrapato/tratamento farmacológico
9.
Radiography (Lond) ; 28(4): 889-896, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35780628

RESUMO

INTRODUCTION: In Australia, sonographer's professional identity is traditionally 'caught' from clinical role models. A four-year undergraduate-postgraduate course introduced professional identity education, with simulated practice, to prepare novice sonographer students prior to clinical practice. Preclinical students learnt sonographer professional behaviour, and humanistic attributes, during simulation designed with volunteer peers as standardised patients, educator role-models, immediate feedback, self-reflection, and longitudinal multi-observer assessment. This paper reports on the transfer of learnt professional behaviour and humanistic attributes to clinical practice. METHODS: Professional behaviour evaluations completed by 94 clinical assessors described 174 students' professional behaviour and attributes one month into their initial clinical practice (2015-6). Student performance of each behaviour, and behavioural category, was quantitatively analysed by modelling binomial proportions with logistic regression. RESULTS: Students demonstrated substantial learning transfer to clinical practice, achieving an overall mean score of 'consistent' sonographer professional behaviour and humanistic attributes (mean score of equal to or >3/4), one month into clinical practice. Professional behaviours varied in transferability, with 'response to patient's questions' showing least efficacy (P < 0.05). Increased deliberate practice with educator role-models improved transfer efficacy significantly (P < 0.001). CONCLUSION: Preclinical application of theory to simulated practice, using standardised patients, educator role-models, immediate feedback, and multi-observer assessment, facilitated substantial transfer of sonographer professional behaviour and attributes to clinical practice. The efficacy of transfer varied but improved with increased deliberate practice and feedback. IMPLICATIONS FOR PRACTICE: The incorporation of preclinical professional behaviour education with simulated practice into the core curriculum of sonographer courses is recommended for the formation of sonographer professional identity, improved clinical outcomes and increased patient safety during the early stages of ultrasound education.


Assuntos
Aprendizagem , Local de Trabalho , Currículo , Retroalimentação , Humanos , Estudantes
10.
Radiography (Lond) ; 28(1): 8-16, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34332858

RESUMO

INTRODUCTION: Little is known about the factors influencing clinical supervisor-assessors' ratings of sonographer students' performance. This study identifies these influential factors and relates them to professional competency standards, with the aim of raising awareness and improving assessment practice. METHODS: This study used archived written comments from 94 clinical assessors describing 174 sonographer students' performance one month into their initial clinical practice (2015-6). Qualitative mixed method analysis revealed factors influencing assessor ratings of student performance and provided an estimate of the valency, association, and frequency of these factors. RESULTS: Assessors provided written comments for 93 % (n = 162/174) of students. Comments totaled 7190 words (mean of 44 words/student). One-third of comment paragraphs were wholly positive, two-thirds were equivocal. None were wholly negative. Thematic analysis revealed eleven factors, and eight sub-factors, influencing assessor impressions of five dimensions of performance. Of the factors mentioned, 84.6 % (n = 853/1008) related to professional competencies. While 15.4 % (n = 155/1008) were unrelated to competencies, instead reflecting humanistic factors such as student motivation, disposition, approach to learning, prospects and impact on supervisor and staff. Factors were prioritised and combined independently, although some associated. CONCLUSION: Clinical assessors formed impressions based on student performance, humanistic behaviours and personal qualities not necessarily outlined in educational outcomes or professional competency standards. Their presence, and interrelations, impact success in clinical practice, through their contribution to, and indication of, competence. IMPLICATIONS FOR PRACTICE: Sonographer student curricula and assessor training should raise awareness of the factors influencing performance ratings and judgement of clinical competence, particularly the importance of humanistic factors. Inclusion of narrative comments, multiple assessors, and broad performance dimensions would enhance clinical assessment of sonographer student performance.


Assuntos
Competência Clínica , Currículo , Humanos , Narração , Competência Profissional , Estudantes
11.
Rev Sci Instrum ; 92(5): 053510, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-34243268

RESUMO

Results of numerical modeling of the interaction of an electron beam propagating across relativistic plasma waves indicate that electron beam filamentation and focusing may occur under certain conditions. The model is based on solving the relativistic equation of motion in three dimensions for the individual electrons in a tenuous Gaussian beam, as they pass through a relativistic plasma wave. Several electron beam and plasma wave parameters were varied, and the results are summarized. One of the results is that the spacing of the electron beam filaments correlates with the wavelength of the plasma wave. The electron beam filaments appear as vertical slabs after the beam exits the plasma waves. The electron beam also compresses to a focus after it exits the plasma, and the focal distance depends on several parameters including the electron beam energy and phase velocity of the relativistic plasma wave. It is suggested that these focusing and filamentation phenomena may be the basis for diagnostics schemes for laser plasma interactions. The parameters used in the model were electron beam energies in the 5-50 keV range and plasma wave properties typical for the beat-wave produced by CO2 lasers, which correspond to the facilities available in our laboratory. The limitations of these results to lower energy density beam and plasma regimes and to higher energy density regimes will be discussed.

12.
Radiography (Lond) ; 27(2): 404-413, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33876732

RESUMO

INTRODUCTION: Traditionally in Australia, sonographer skills are learnt on patients in clinical practice. A four-year undergraduate-postgraduate course introduced ultrasound simulation to prepare novice sonographer students for interaction with patients. Second-year students learnt psychomotor and patient-sonographer communication skills during simulation using commercial ultrasound machines and volunteer year-group peers as standardised patients. This paper reports on the transfer of the ultrasound skills learnt in simulation to clinical practice. METHODS: Clinical performance evaluations were completed by 94 supervisors involved in the initial clinical practice of 174 post-simulation second-year students over a two-year period (2015-2016). Student performance of each component skill, and skill category, was analysed by modelling binomial proportions with logistic regression. RESULTS: Students demonstrated substantial transfer of learnt ultrasound skills to achieve a mean of advanced beginner competence (mean score of equal to or >3/5) in complex psychomotor and patient-sonographer communication skills, as measured one month into clinical practice. Knowledge and skill components, or sub-tasks, varied significantly (P < 0.001) in transferability. Scanning tasks in general, particularly the skill of 'extending the examination', transferred with significantly (P < 0.001) less efficacy than pre-exam, instrumentation, post-exam, and additional tasks. Skill transfer improved significantly (P < 0.001) following increased deliberate practice with tutor feedback. CONCLUSION: Preclinical simulation, using standardised patients, clearly stated objectives to manage cognitive load and immediate tutor feedback, facilitated substantial transfer of ultrasound skills to clinical practice. The efficacy of skill transfer varied but improved with increased deliberate practice and feedback quality. IMPLICATIONS FOR PRACTICE: The incorporation of preclinical simulation into the core curriculum of sonographer courses is recommended to improve student performance, reduce the burden on clinical staff and increase patient safety during the early stages of ultrasound education.


Assuntos
Educação de Graduação em Medicina , Treinamento por Simulação , Competência Clínica , Humanos , Estudantes , Ultrassonografia
13.
Insect Mol Biol ; 19(3): 273-82, 2010 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-20002796

RESUMO

Tick control strategies rely heavily on chemicals (acaricides), most of which target the central nervous system. With increasing resistance, new acaricides are urgently needed but knowledge of tick neurobiology is surprisingly limited, notably the number of neural-specific gene sequences. One thousand and eight expressed sequence tags (ESTs) were obtained from a normalized cDNA library from Rhipicephalus sanguineus synganglia. Putative functional identities were assigned to 44% whereas 34% were unknown/novel sequences. Of particular interest were ESTs encoding a chitinase-like enzyme, an acetylcholinesterase and four transmembrane receptors including two glutamate-gated chloride channel receptors, a leucokinin-like receptor and a nicotinic acetylcholine receptor alpha-subunit. This study highlights the benefits of using both neural tissues and normalized libraries in an EST-approach for identifying potential acaricide targets expressed as rare transcripts.


Assuntos
Gânglios/metabolismo , Perfilação da Expressão Gênica , Rhipicephalus sanguineus/genética , Acaricidas/farmacologia , Acetilcolinesterase/genética , Animais , Quitinases/genética , Canais de Cloreto/genética , Canais de Cloreto/metabolismo , Cães , Descoberta de Drogas , Etiquetas de Sequências Expressas , Regulação da Expressão Gênica/efeitos dos fármacos , Biblioteca Gênica , Genes de Insetos/genética , Proteínas de Insetos/química , Proteínas de Insetos/genética , Filogenia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores de Neuropeptídeos/genética , Receptores de Neuropeptídeos/metabolismo , Rhipicephalus sanguineus/efeitos dos fármacos , Rhipicephalus sanguineus/enzimologia , Alinhamento de Sequência
14.
J Cell Biol ; 146(1): 165-80, 1999 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-10402468

RESUMO

Eukaryotic organisms utilize microtubule-dependent motors of the kinesin and dynein superfamilies to generate intracellular movement. To identify new genes involved in the regulation of axonal transport in Drosophila melanogaster, we undertook a screen based upon the sluggish larval phenotype of known motor mutants. One of the mutants identified in this screen, roadblock (robl), exhibits diverse defects in intracellular transport including axonal transport and mitosis. These defects include intra-axonal accumulations of cargoes, severe axonal degeneration, and aberrant chromosome segregation. The gene identified by robl encodes a 97-amino acid polypeptide that is 57% identical (70% similar) to the 105-amino acid Chlamydomonas outer arm dynein-associated protein LC7, also reported here. Both robl and LC7 have homology to several other genes from fruit fly, nematode, and mammals, but not Saccharomyces cerevisiae. Furthermore, we demonstrate that members of this family of proteins are associated with both flagellar outer arm dynein and Drosophila and rat brain cytoplasmic dynein. We propose that roadblock/LC7 family members may modulate specific dynein functions.


Assuntos
Transporte Axonal , Proteínas de Transporte/fisiologia , Proteínas de Drosophila , Dineínas/metabolismo , Flagelos/fisiologia , Mitose , Proteínas de Protozoários , Sequência de Aminoácidos , Animais , Proteínas de Transporte/química , Proteínas de Transporte/genética , Chlamydomonas , Clonagem Molecular , Sequência Conservada , Drosophila melanogaster , Dineínas/química , Feminino , Genes de Insetos/genética , Genes de Insetos/fisiologia , Microscopia Eletrônica , Mitose/genética , Dados de Sequência Molecular , Mutação , Filogenia , Proteínas de Plantas , Reprodução/genética , Alinhamento de Sequência
15.
Parasitology ; 136(8): 867-74, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19493370

RESUMO

Harnessing the full utility of extensive gene sequences recently available for the economically important sea louse, Lepeophtheirus salmonis, requires the adaptation of modern molecular biology approaches to this non-model organism. Using a putative microsomal prostaglandin E synthase type-2 (PGES2) as a candidate gene, we investigated gene-knockdown by double-stranded RNA interference (dsRNAi) in the small free-living and the larger parasitic stages of L. salmonis. dsRNA was administered to nauplius and copepodid stages by immersion for 7 h. Pre-adult and adults received dsRNA by intra-haemocoelic injection. The extent, speed and persistence of the knockdown effects were determined by RT-PCR. LsPGES2 was abundantly expressed in all life stages, including the non-parasitic stages. Administration of dsRNA to nauplius and copepodids by immersion had no effect on mortality rates and moulting through to copepodids was observed. Dramatic knockdown of LsPGES2 was observed within 7 h and persisted for at least 48 h. Injection of dsRNA had no effect on mortality in pre-adults and adults, but knockdown of LsPGES2 was apparent within 24 h, reaching 95% over the 72 h and was persistent for at least 120 h. The methods developed resulted in rapid and persistent knockdown in L. salmonis suitable for studies in the different stadia.


Assuntos
Copépodes/genética , Técnicas de Silenciamento de Genes/métodos , Oxirredutases Intramoleculares/genética , Interferência de RNA , Animais , Feminino , Genes Mitocondriais/genética , Injeções , Prostaglandina-E Sintases , RNA de Cadeia Dupla/genética , Salmo salar/parasitologia
16.
Parasitology ; 136(10): 1221-34, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19631009

RESUMO

Many vector-borne pathogens whose primary vectors are generalists, such as Ixodid ticks, can infect a wide range of host species and are often zoonotic. Understanding their transmission dynamics is important for the development of disease management programmes. Models exist to describe the transmission dynamics of such diseases, but are necessarily simplistic and generally limited by knowledge of vector population dynamics. They are typically deterministic SIR-type models, which predict disease dynamics in a single, non-spatial, closed patch. Here we explore the limitations of such a model of louping-ill virus dynamics by challenging it with novel field data. The model was only partially successful in predicting Ixodes ricinus density and louping-ill virus prevalence at 6 Scottish sites. We extend the existing multi-host model by forming a two-patch model, incorporating the impact of roaming hosts. This demonstrates that host movement may account for some of the discrepancies between the original model and empirical data. We conclude that insights into the dynamics of multi-host vector-borne pathogens can be gained by using a simple two-patch model. Potential improvements to the model, incorporating aspects of spatial and temporal heterogeneity, are outlined.


Assuntos
Vetores Aracnídeos/virologia , Cervos/fisiologia , Vírus da Encefalite Transmitidos por Carrapatos/fisiologia , Encefalite Transmitida por Carrapatos/transmissão , Galliformes/virologia , Interações Hospedeiro-Patógeno , Ixodes/virologia , Animais , Doenças das Aves/virologia , Cervos/parasitologia , Cervos/virologia , Vírus da Encefalite Transmitidos por Carrapatos/isolamento & purificação , Encefalite Transmitida por Carrapatos/virologia , Modelos Biológicos , Movimento , Dinâmica Populacional , Prevalência , Escócia/epidemiologia , Infestações por Carrapato/parasitologia
17.
Eur J Gynaecol Oncol ; 30(6): 609-15, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-20099488

RESUMO

PURPOSE OF INVESTIGATION: To evaluate the prognostic significance for overall survival rate for the marker combination TPS and CA125 in ovarian cancer patients after three chemotherapy courses during long-term clinical follow-up. METHODS: The overall survival of 212 (out of 213) ovarian cancer patients (FIGO Stages I-IV) was analyzed in a prospective multicenter study during a 10-year clinical follow-up by univariate and multivariate analysis. RESULTS: In patients with ovarian cancer FIGO Stage I (34 patients) or FIGO Stage II (30 patients) disease, the univariate and multivariate analysis of the 10-year overall survival data showed that CA125 and TPS serum levels were not independent prognostic factors. In the FIGO Stage III group (112 patients), the 10-year overall survival was 15.2%; while in the FIGO Stage IV group (36 patients) a 10-year overall survival of 5.6% was seen. Here, the tumor markers CA125 and TPS levels were significant prognostic factors in both univariate and multivariate analysis (p < 0.0001). In a combined FIGO Stage III + FIGO Stage IV group (60 patients with optimal debulking surgery), multivariate analysis demonstrated that CA125 and TPS levels were independent prognostic factors. For patients in this combined FIGO Stage III + IV group having both markers below respective discrimination level, 35.3% survived for more than ten years, as opposed to patients having one marker above the discrimination level where the 10-year survival was reduced to 10% of the patients. For patients showing both markers above the respective discrimination level, none of the patients survived for the 10-year follow-up time. CONCLUSION: In FIGO III and IV ovarian cancer patients, only patients with CA 125 and TPS markers below the discrimination level after three chemotherapy courses indicated a favorable prognosis. Patients with an elevated level of CA 125 or TPS or both markers after three chemotherapy courses showed unfavorable prognosis.


Assuntos
Antineoplásicos/administração & dosagem , Antígeno Ca-125/sangue , Neoplasias Ovarianas/sangue , Neoplasias Ovarianas/tratamento farmacológico , Peptídeos/sangue , Idoso , Esquema de Medicação , Feminino , Seguimentos , Humanos , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Neoplasias Ovarianas/cirurgia , Prognóstico , Análise de Sobrevida
18.
Sci Total Environ ; 652: 1339-1346, 2019 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-30586819

RESUMO

Field monitoring of groundwater contamination plumes is an important component of managing risks for downgradient receptors and remedial strategies that rely on monitored natural attenuation. Collection of groundwater quality data can however take a considerable effort and be associated with high cost. Here, we investigated the relative merits of analyzing groundwater quality data using spatial compared to spatiotemporal statistical modelling and assessed the accuracy of both methods and implications for data collection requirements. The aim of this was to determine whether the quantity of data collected can be reduced, while retaining the same level of estimation accuracy, by analyzing groundwater contamination data using a spatiotemporal model which "borrows strength" across time, rather than a spatial model for individual sampling events. To capture the variability encountered under field conditions, we used three hypothetical groundwater contamination plumes with increasing complexity, and site data for a large groundwater gasoline additive plume. The results show that spatiotemporal methods can increase efficiency markedly so that, in comparison with repeated spatial analysis, spatiotemporal methods can achieve the same level of performance but with smaller sample sizes.

19.
Science ; 364(6441)2019 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-31097641

RESUMO

The Kuiper Belt is a distant region of the outer Solar System. On 1 January 2019, the New Horizons spacecraft flew close to (486958) 2014 MU69, a cold classical Kuiper Belt object approximately 30 kilometers in diameter. Such objects have never been substantially heated by the Sun and are therefore well preserved since their formation. We describe initial results from these encounter observations. MU69 is a bilobed contact binary with a flattened shape, discrete geological units, and noticeable albedo heterogeneity. However, there is little surface color or compositional heterogeneity. No evidence for satellites, rings or other dust structures, a gas coma, or solar wind interactions was detected. MU69's origin appears consistent with pebble cloud collapse followed by a low-velocity merger of its two lobes.

20.
Br J Cancer ; 99(4): 597-603, 2008 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-18665163

RESUMO

tAnGo is a large randomised trial assessing the addition of gemcitabine(G) to paclitaxel(T), following epirubicin(E) and cyclophosphamide(C) in women with invasive higher risk early breast cancer. To assess the safety and tolerability of adding G, a detailed safety substudy was undertaken. A total of 135 patients had cardiac, pulmonary and hepatic function assessed at (i) randomisation, (ii) mid-chemotherapy, (iii) immediately post-chemotherapy and (iv) 6 months post-chemotherapy. Skin toxicity was assessed during radiotherapy. No differences were detected in FEV(1) or FVC levels between treatment arms or time points. Diffusion capacity (TL(CO)) reduced during treatment (P<0.0001), with a significantly lower drop in EC-GT patients (P=0.02). Most of the reduction occurred during EC and recovered by 6-months post treatment. There was no difference in cardiac function between treatment arms. Only 11 patients had echocardiography/MUGA results change from normal to abnormal during treatment, with only five having LVEF<50%. Transient transaminitis occurred in both treatment arms with significantly more in EC-GT patients post-chemotherapy (AST P=0.03, ALT P=0.003), although the majority was low grade. There was no correlation between transaminitis and other toxicities. Both treatment regimens reported temporary reductions in pulmonary functions and transient transaminitis levels. Despite these being greater with EC-GT, both regimens appear well tolerated.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Coração/efeitos dos fármacos , Fígado/efeitos dos fármacos , Pulmão/efeitos dos fármacos , Adenocarcinoma/tratamento farmacológico , Adenocarcinoma/secundário , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Neoplasias da Mama/patologia , Carcinoma Ductal de Mama/tratamento farmacológico , Carcinoma Ductal de Mama/secundário , Carcinoma Lobular/tratamento farmacológico , Carcinoma Lobular/secundário , Quimioterapia Adjuvante , Ciclofosfamida/administração & dosagem , Desoxicitidina/administração & dosagem , Desoxicitidina/análogos & derivados , Intervalo Livre de Doença , Epirubicina/administração & dosagem , Feminino , Testes de Função Cardíaca , Humanos , Testes de Função Hepática , Paclitaxel/administração & dosagem , Estudos Prospectivos , Testes de Função Respiratória , Taxa de Sobrevida , Gencitabina
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