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1.
J Acoust Soc Am ; 155(2): 1162-1181, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38341747

RESUMO

Shooting sound in practical situations with propagation distances up to 300 m is investigated by means of model calculations and measurements. The results illustrate uncertainties in the model calculations for practical situations. The measurements were performed with various small-caliber weapons. Microphones were placed at positions screened by a noise barrier, and also at unscreened positions. The measured signals contain muzzle sound and bullet sound. The model calculations for muzzle sound and bullet sound take into account emission spectra and various propagation attenuation terms, including ground attenuation and barrier attenuation. The bullet sound model is based on a nonlinear theory of N waves generated by supersonic projectiles. For the unscreened situation, model and measurement results show that the sound levels are considerably reduced by ground attenuation. Ground-level variations and ground roughness in the measurement area play an important role. At a 300 m distance, the A-weighted bullet sound level is higher than the A-weighted muzzle sound level, which underlines the importance of bullet sound. For the screened situation, model and measurement results are used to analyze diffraction of bullet sound by the horizontal and vertical edges of the barrier. The diffraction is explained by considering Fresnel zones on the bullet trajectory.

2.
Neuropsychologia ; 170: 108214, 2022 06 06.
Artigo em Inglês | MEDLINE | ID: mdl-35318029

RESUMO

Various studies claim that early-learned, culture-typical (canonical) finger configurations used to communicate or represent numerosity, have stronger connections to numerical concepts stored in long-term memory than cultural-unfamiliar finger configurations, thereby allowing for faster access to their numerical meaning. The current study investigated whether presentation of canonical finger configurations gesturing numerosities 1-4 or 6-9 would facilitate young adults' behavioral and neural processing of Arabic numerals. Thirty-one adults performed a number comparison task in which they had to decide whether simultaneously presented Arabic numerals and canonical or non-canonical finger configurations showed the same or a different numerosity, while measuring their performance and Event-Related Potentials (ERPs). The results showed faster responses when comparisons involved canonical (versus non-canonical) finger configurations, but only on numerosity-congruent trials where finger configuration and Arabic numeral matched in number identity. Canonical, and small-number finger configurations 1-4 in general (irrespective of their canonicity), also elicited enhanced amplitude of the early right-parietal P2p, and the later centro-parietal P3 on numerosity-congruent trials. We suggest these P2p and P3 findings respectively reflect facilitated numerical access and easier categorization of canonical finger-numeral configurations. The current results provide behavioral and neurophysiological evidence for the embodiment of culture-specific, canonical, finger-numeral configurations, and their link with other number representations in the adult brain, likely emerging from their more frequent use in daily life communication and/or in early childhood during number symbol acquisition.


Assuntos
Potenciais Evocados , Dedos , Encéfalo , Pré-Escolar , Potenciais Evocados/fisiologia , Dedos/fisiologia , Humanos , Aprendizagem , Extremidade Superior , Adulto Jovem
3.
BJS Open ; 5(5)2021 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-34518874

RESUMO

BACKGROUND: Infectious complications following experimental pancreatitis involve major disruptions in the gut microbiota. The aim of this study was to characterize this disruption by examining the spatioregional distribution in microbial community structure and function following experimental pancreatitis associated with pancreatic infection. METHODS: Mice were subjected to infusion of the pancreatic duct with either taurocholate to induce necrotizing pancreatitis or normal saline (control group). The spatial (lumen versus mucosa) and regional composition and function of the microbiota from the duodenum, ileum, caecum, colon, pancreas and blood were evaluated using 16S rRNA gene amplicon sequencing. RESULTS: Mice that developed necrotizing pancreatitis demonstrated a decrease in microbial richness and significantly altered microbiota in distal parts of the gastrointestinal tract, compared with controls. Among the most differentially increased taxa were the mucus-degrading Akkermansia muciniphila, and there was a decrease of butyrate-producing bacteria following pancreatitis. Application of the SourceTracker tool to the generated metadata indicated that the duodenum was the most probable source of bacteria that subsequently infected pancreatic tissue in this model. The functional prediction annotation using pathway analyses indicated a diminished capacity of the caecal microbiota to metabolize carbohydrate, and fatty and amino acids. DISCUSSION: The distal gut microbiota was significantly impacted in this model of experimental necrotizing pancreatitis. Data suggest that the duodenal microbiota might also play a role in bacterial translation and secondary infections.


Assuntos
Microbioma Gastrointestinal , Pancreatite , Animais , Colo , Microbioma Gastrointestinal/genética , Humanos , Camundongos , RNA Ribossômico 16S/genética , Ácido Taurocólico
4.
J Intern Med ; 288(2): 207-218, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32372544

RESUMO

BACKGROUND: There is increasing recognition that heart failure (HF) and cancer are conditions with a number of shared characteristics. OBJECTIVES: To explore the association between tumour biomarkers and HF outcomes. METHODS: In 2,079 patients of BIOSTAT-CHF cohort, we measured six established tumour biomarkers: CA125, CA15-3, CA19-9, CEA, CYFRA 21-1 and AFP. RESULTS: During a median follow-up of 21 months, 555 (27%) patients reached the primary end-point of all-cause mortality. CA125, CYFRA 21-1, CEA and CA19-9 levels were positively correlated with NT-proBNP quartiles (all P < 0.001, P for trend < 0.001) and were, respectively, associated with a hazard ratio of 1.17 (95% CI 1.12-1.23; P < 0.0001), 1.45 (95% CI 1.30-1.61; P < 0.0001), 1.19 (95% CI 1.09-1.30; P = 0.006) and 1.10 (95% CI 1.05-1.16; P < 0.001) for all-cause mortality after correction for BIOSTAT risk model (age, BUN, NT-proBNP, haemoglobin and beta blocker). All tumour biomarkers (except AFP) had significant associations with secondary end-points (composite of all-cause mortality and HF hospitalization, HF hospitalization, cardiovascular (CV) mortality and non-CV mortality). ROC curves showed the AUC of CYFRA 21-1 (0.64) had a noninferior AUC compared with NT-proBNP (0.68) for all-cause mortality (P = 0.08). A combination of CYFRA 21-1 and NT-proBNP (AUC = 0.71) improved the predictive value of the model for all-cause mortality (P = 0.0002 compared with NT-proBNP). CONCLUSIONS: Several established tumour biomarkers showed independent associations with indices of severity of HF and independent prognostic value for HF outcomes. This demonstrates that pathophysiological pathways sensed by these tumour biomarkers are also dysregulated in HF.


Assuntos
Biomarcadores Tumorais/sangue , Insuficiência Cardíaca/sangue , Insuficiência Cardíaca/mortalidade , Idoso , Antígenos de Neoplasias/sangue , Antígenos Glicosídicos Associados a Tumores/sangue , Antígeno Ca-125/sangue , Antígeno Carcinoembrionário/sangue , Feminino , Seguimentos , Hospitalização , Humanos , Queratina-19/sangue , Masculino , Proteínas de Membrana/sangue , Peptídeo Natriurético Encefálico/sangue , Fragmentos de Peptídeos/sangue , alfa-Fetoproteínas/análise
5.
BJS Open ; 4(1): 3-15, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32011822

RESUMO

BACKGROUND: Genetic risk factors can provide insight into susceptibility for acute pancreatitis (AP) and disease progression towards (infected) necrotizing pancreatitis and persistent organ failure. The aim of the study was to undertake a systematic review of the genetic evidence for AP. METHODS: Online databases (MEDLINE, Embase, BIOSIS, Web of Science, Cochrane Library) were searched to 8 February 2018. Studies that reported on genetic associations with AP susceptibility, severity and/or complications were eligible for inclusion. Meta-analyses were performed of variants that were reported by at least two data sources. Venice criteria and Bayesian false-discovery probability were applied to assess credibility. RESULTS: Ninety-six studies reporting on 181 variants in 79 genes were identified. In agreement with previous meta-analyses, credible associations were established for SPINK1 (odds ratio (OR) 2·87, 95 per cent c.i. 1·89 to 4·34), IL1B (OR 1·23, 1·06 to 1·42) and IL6 (OR 1·64, 1·15 to 2·32) and disease risk. In addition, two novel credible single-nucleotide polymorphisms were identified in Asian populations: ALDH2 (OR 0·48, 0·36 to 0·64) and IL18 (OR 1·47, 1·18 to 1·82). Associations of variants in TNF, GSTP1 and CXCL8 genes with disease severity were identified, but were of low credibility. CONCLUSION: Genetic risk factors in genes related to trypsin activation and innate immunity appear to be associated with susceptibility to and severity of AP.


ANTECEDENTES: Los factores de riesgo genético pueden contribuir a determinar la susceptibilidad para desarrollar una pancreatitis aguda (acute pancreatitis, AP) y de su progresión a pancreatitis necrotizante (infectada) e insuficiencia orgánica crónica. Nuestro objetivo fue revisar de forma sistemática la evidencia genética de la pancreatitis aguda. MÉTODOS: Se revisaron las bases de datos electrónicas (MEDLINE, Embase, BIOSIS, Web of Science, Cochrane Library) hasta febrero de 2018. Se incluyeron estudios que presentaban información de las asociaciones genéticas y la susceptibilidad de AP, gravedad y/o complicaciones. Se realizó un metaanálisis de las variantes genéticas descritas en al menos dos fuentes. Se aplicaron los criterios de Venecia y la probabilidad bayesiana de falsa alarma para la valoración de la credibilidad. RESULTADOS: Se identificaron 96 estudios que analizaron 181 variantes en 79 genes. De acuerdo con un metaanálisis previo, se establecieron asociaciones creibles con el riesgo de enfermedad para SPINK1 (razón de oportunidades, odds ratio, OR 2,87, i.c. del 95% 1,89-4,34), IL1B (OR 1,23, i.c. del 95% 1,06-1,42) e IL6 (OR 1,64, i.c. del 95% 1,15-2,32). Además, en poblaciones asiáticas, se identificaron dos nuevos polimorfismos de nucleótico único (SNP) creibles en ALDH2 (OR 0,48, i.c. del 95% 0,36-0,64) e IL18 (OR 1,47, i.c. del 95% 1,18-1,82). En cuanto a la gravedad de la enfermedad se identificaron variantes en los genes TNF, GSTP1 y CXCL8, pero de baja credibilidad en función de nuestra evaluación. CONCLUSIÓN: Los factores de riesgo genéticos en genes relacionados con la activación de la tripsina y la inmunidad innata parecen ser estar asociados con la susceptibilidad y gravedad de la pancreatitis aguda.


Assuntos
Pancreatite/genética , Polimorfismo de Nucleotídeo Único , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Humanos , Interleucina-1beta/genética , Interleucina-6/genética , Fatores de Risco , Inibidor da Tripsina Pancreática de Kazal/genética
6.
FEMS Microbiol Lett ; 365(21)2018 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-30247563

RESUMO

There is a growing interest in understanding the fate and behaviour of probiotic microorganisms and bioactive compounds during passage of the human gastrointestinal tract (GIT). Here, we report the development of a small volume in vitro model called The smallest Intestine (TSI) with increased throughput focusing on simulating passage through the stomach and small intestine (SI). The basic TSI module consists of five reactors, with a working volume of 12 ml each. During the simulated passage through the SI, bile is absorbed and pH is adjusted to physiologically relevant values for duodenum, jejunum and ileum. A consortium of seven representative bacterial members of the ileum microbiota is included in the ileal stage of the model. The behaviour of three putative probiotic Lactobacillus strains during in vitro simulated upper GIT passage was tested in the model and results were compared to previous studies describing probiotic survival. It was found, that probiotic persistence is strongly related to whether food was ingested, but also to presence of the ileal microbiota, which significantly impacted probiotic survival. In conclusion, TSI allows testing a substantial number of samples, at low cost and short time, and is thus suitable as an in vitro screening platform.


Assuntos
Reatores Biológicos , Trato Gastrointestinal/fisiologia , Intestino Delgado/fisiologia , Lactobacillus/metabolismo , Probióticos , Duodeno/microbiologia , Duodeno/fisiologia , Trato Gastrointestinal/microbiologia , Ensaios de Triagem em Larga Escala , Humanos , Concentração de Íons de Hidrogênio , Intestino Delgado/microbiologia , Viabilidade Microbiana , Modelos Biológicos
7.
Phytopathology ; 107(12): 1468-1478, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-28730873

RESUMO

Tolerance is defined as the ability of one cultivar to yield more than another cultivar under similar disease severity. If both cultivars suffer an equal loss in healthy (green) leaf area duration (HAD) over the grain filling period due to disease presence, then the yield loss per unit HAD loss is smaller for a more tolerant cultivar. Little is understood of what physiological and developmental traits of cultivars determine disease tolerance. In this study, we use a mathematical model of wheat to investigate the effect of a wide range of wheat phenotypes on tolerance. During the phase from stem extension to anthesis, the model calculates the assimilate source and sink potential, allowing for dynamic changes to the source-sink balance by partitioning assimilates between ear development and storage of water-soluble carbon (WSC) reserves, according to assimilate availability. To quantify tolerance, rates of epidemic progress were varied on each phenotype, leading to different levels of HAD loss during the postanthesis, grain-filling period. Model outputs show that the main determinant of tolerance is the total amount of assimilate produced per grain during the rapid grain-fill period, leading to a strong positive correlation between HAD per grain and tolerance. Reductions in traits that affect carbon assimilation rate and increases in traits that determine the amount of structural biomass in the plant increase disease tolerance through their associated reduction in number of grains per ear. Some of the most influential traits are the canopy green area index, carbon use efficiency, and leaf specific weight. Increased WSC accumulation can either increase or decrease tolerance. Furthermore, a cultivar is shown to be maximally tolerant when a crop is able to just fill its total sink size in the presence of disease. The model has identified influential functional traits and established that their associations with tolerance have a mechanistic basis.


Assuntos
Modelos Biológicos , Doenças das Plantas/imunologia , Triticum/fisiologia , Biomassa , Cruzamento , Resistência à Doença , Grão Comestível/imunologia , Grão Comestível/fisiologia , Modelos Lineares , Fenótipo , Folhas de Planta/imunologia , Folhas de Planta/fisiologia , Caules de Planta/imunologia , Caules de Planta/fisiologia , Triticum/imunologia , Água/fisiologia
8.
Plant Pathol ; 65(8): 1380-1389, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27708459

RESUMO

Two key decisions that need to be taken about a fungicide treatment programme are (i) the number of applications that should be used per crop growing season, and (ii) the dosage that should be used in each application. There are two opposing considerations, with control efficacy improved by a higher number of applications and higher dose, and resistance management improved by a lower number of applications and lower dose. Resistance management aims to prolong the effective life of the fungicide, defined as the time between its introduction onto the market for use on the target pathogen, and the moment when effective control is lost due to a build-up of fungicide resistance. Thus, the question is whether there are optimal combinations of dose rate and number of applications that both provide effective control and lead to a longer effective life. In this paper, it is shown how a range of spray programmes can be compared and optimal programmes selected. This is explored with Zymoseptoria tritici on wheat and a quinone outside inhibitor (QoI) fungicide. For this pathogen-fungicide combination, a single treatment provided effective control under the simulated disease pressure, but only if the application timing was optimal and the dose was close to the maximum permitted. Programmes with three applications were generally not optimal as they exerted too much selection for resistance. Two-application fungicide programmes balanced effective control with reasonable flexibility of dose and application timing, and low resistance selection, leading to long effective lives of the fungicide.

9.
Sci Total Environ ; 573: 1010-1020, 2016 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-27607904

RESUMO

Agricultural use of plant protection products can result in exposure of bystanders, residents, operators and workers. Within the European Union (EU) FP7 project BROWSE, a tool based on a set of models and scenarios has been developed, aiming to assess the risk of exposure of humans to these products. In the present version of the tool only a first conservative tier is available for outdoor vapour exposure assessment. In the vapour exposure evaluation, the target concentrations in air at 10m distance from the edge of a treated field are calculated for specific scenarios for each EU regulatory zone. These scenarios have been selected to represent reasonable worst case volatilisation conditions. The exposure assessment is based on a series of weekly applications in a five year period to cover a wide range of meteorological conditions. The volatilisation from the crop is calculated using the PEARL model and this PEARL output provides the emission strength used as input for the short term version of the atmospheric transport model OPS. The combined PEARL-OPS model is tested against measurements from a field experiment. First results of this test show that the mean concentration level was predicted fairly well. However, sometimes the differences between observations and simulations were found to be substantial. Improvements are suggested for the vapour exposure scenarios as well as for further model development. In the current version of the BROWSE tool a simplified procedure is used to assess single and multiple applications. The actual period of application and the time of application during the day are fixed, and the growth stage of the crop cannot be taken into account. Moreover, competing processes such as penetration of the substance into the plant tissue are not considered. The effect of these factors on the target exposure concentrations is discussed.


Assuntos
Agroquímicos/análise , Poluentes Atmosféricos/análise , Exposição por Inalação/análise , Modelos Teóricos , Exposição Ocupacional/análise , Produtos Agrícolas/crescimento & desenvolvimento , União Europeia , Humanos , Características de Residência , Volatilização , Tempo (Meteorologia)
10.
Orthop Traumatol Surg Res ; 101(6): 763-5, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26323185

RESUMO

Subperiosteal abscess formation is almost exclusively seen secondary to underlying hematogenous infected osteomyelitis or secondary as a result of a contagious focus. We present an unusual case of a 9-year-old girl with progressive ankle pain due to an isolated subperiosteal abscess of the distal fibula without concomitant osteomyelitis. The subperiosteal abscess was most likely caused by hematogenous spread to the periosteal region of the distal fibula located above the highly vascularized metaphysis. Remarkably, there were no signs of osteomyelitis on either MRI or during surgical inspection. She was successfully treated with debridement and antibiotic therapy. We hypothesize that subperiosteal abscess formation near the metaphysis originates in the periosteal region and not from outward extension from the sinusoidal veins in the intrametaphyseal area to the cortex and subperiosteal region.


Assuntos
Abscesso/cirurgia , Desbridamento/métodos , Fíbula/cirurgia , Osteomielite/cirurgia , Abscesso/diagnóstico , Abscesso/etiologia , Criança , Feminino , Fíbula/patologia , Humanos , Imageamento por Ressonância Magnética , Osteomielite/complicações , Osteomielite/diagnóstico
11.
Langmuir ; 30(29): 8687-96, 2014 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-25026245

RESUMO

Low-molecular-weight (LMW) emulsifiers are used to promote controlled destabilization in many dairy-type emulsions in order to obtain stable foams in whippable products. The relation between fat globule aggregation induced by three LMW emulsifiers, lactic acid ester of monoglyceride (LACTEM), saturated monoglyceride (GMS), and unsaturated monoglyceride (GMU) and their effect on interfacial protein displacement was investigated. It was found that protein displacement by LMW emulsifiers was not necessary for fat globule aggregation in emulsions, and conversely fat globule aggregation was not necessarily accompanied by protein displacement. The three LMW emulsifiers had very different effects on emulsions. LACTEM induced shear instability of emulsions, which was accompanied by protein displacement. High stability was characteristic for emulsions with GMS where protein was displaced from the interface. Emulsions containing GMU were semisolid, but only low concentrations of protein were detected in the separated serum phase. The effects of LACTEM, GMS, and GMU may be explained by three different mechanisms involving formation of interfacial α-gel, pickering stabilization and increased exposure of bound casein to the water phase. The latter may facilitate partial coalescence. Stabilizing hydrocolloids did not have any effect on the LMW emulsifiers' ability to induce protein displacement.


Assuntos
Caseínas/química , Quelantes/química , Emulsificantes/química , Ácido Láctico/química , Monoglicerídeos/química , Emulsões , Ésteres , Tecnologia de Alimentos , Géis , Reologia
12.
Neuroscience ; 250: 1-7, 2013 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-23831423

RESUMO

This study investigated the effects of a long-term transcutaneous electrical nerve stimulation (TENS) treatment on cortical motor representation in patients with multiple sclerosis (MS). In this double-blind crossover design, patients received either TENS or sham stimulation for 3 weeks (1h per day) on the median nerve region of the most impaired hand, followed by the other stimulation condition after a washout period of 6 months. Cortical motor representation was mapped using transcranial magnetic stimulation (TMS) at the baseline and after the 3-week stimulation protocol. Our results revealed that 3 weeks of daily stimulation with TENS significantly decreased the cortical motor representation of the stimulated muscle in MS patients. Although the mechanisms underlying this decrease remain unclear, our findings indicate that TENS has the ability to induce long-term reorganization in the motor cortex of MS patients.


Assuntos
Córtex Motor/fisiopatologia , Esclerose Múltipla/fisiopatologia , Esclerose Múltipla/terapia , Estimulação Elétrica Nervosa Transcutânea/efeitos adversos , Adulto , Mapeamento Encefálico , Estudos Cross-Over , Interpretação Estatística de Dados , Método Duplo-Cego , Eletromiografia , Feminino , Lateralidade Funcional/fisiologia , Gravitação , Humanos , Assistência de Longa Duração , Pessoa de Meia-Idade , Músculo Esquelético/inervação , Músculo Esquelético/fisiologia , Plasticidade Neuronal/fisiologia , Estimulação Magnética Transcraniana
13.
Phytopathology ; 103(12): 1209-19, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23859011

RESUMO

Strategies to slow fungicide resistance evolution often advocate early "prophylactic" fungicide application and avoidance of "curative" treatments where possible. There is little evidence to support such guidance. Fungicide applications are usually timed to maximize the efficiency of disease control during the yield-forming period. This article reports mathematical modeling to explore whether earlier timings might be more beneficial for fungicide resistance management compared with the timings that are optimal for efficacy. There are two key timings for fungicide treatment of winter wheat in the United Kingdom: full emergence of leaf three (counting down the canopy) and full emergence of the flag leaf (leaf 1). These timings (referred to as T1 and T2, respectively) maximize disease control on the upper leaves of the crop canopy that are crucial to yield. A differential equation model was developed to track the dynamics of leaf emergence and senescence, epidemic growth, fungicide efficacy, and selection for a resistant strain. The model represented Zymoseptoria tritici on wheat treated twice at varying spray timings. At all fungicide doses tested, moving one or both of the two sprays earlier than the normal T1 and T2 timings reduced selection but also reduced efficacy. Despite these opposing effects, at a fungicide dose just sufficient to obtain effective control, the T1 and T2 timings optimized fungicide effective life (the number of years that effective control can be maintained). At a higher dose, earlier spray timings maximized effective life but caused some reduction in efficacy, whereas the T1 and T2 timings maximized efficacy but resulted in an effective life 1 year shorter than the maximum achievable.


Assuntos
Ascomicetos/efeitos dos fármacos , Farmacorresistência Fúngica , Fungicidas Industriais/administração & dosagem , Doenças das Plantas/prevenção & controle , Triticum/microbiologia , Ascomicetos/fisiologia , Modelos Teóricos , Doenças das Plantas/microbiologia , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/microbiologia , Fatores de Tempo , Triticum/crescimento & desenvolvimento , Reino Unido
14.
J Environ Qual ; 41(1): 253-61, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22218193

RESUMO

In the new Dutch decision tree for the evaluation of pesticide leaching to groundwater, spatially distributed soil data are used by the GeoPEARL model to calculate the 90th percentile of the spatial cumulative distribution function of the leaching concentration in the area of potential usage (SP90). Until now it was not known to what extent uncertainties in soil and pesticide properties propagate to spatially aggregated parameters like the SP90. A study was performed to quantify the uncertainties in soil and pesticide properties and to analyze their contribution to the uncertainty in SP90. First, uncertainties in the soil and pesticide properties were quantified. Next, a regular grid sample of points covering the whole of the agricultural area in the Netherlands was randomly selected. At the grid nodes, realizations from the probability distributions of the uncertain inputs were generated and used as input to a Monte Carlo uncertainty propagation analysis. The analysis showed that the uncertainty concerning the SP90 is 10 times smaller than the uncertainty about the leaching concentration at individual point locations. The parameters that contribute most to the uncertainty about the SP90 are, however, the same as the parameters that contribute most to uncertainty about the leaching concentration at individual point locations (e.g., the transformation half-life in soil and the coefficient of sorption on organic matter). Taking uncertainties in soil and pesticide properties into account further leads to a systematic increase of the predicted SP90. The important implication for pesticide regulation is that the leaching concentration is systematically underestimated when these uncertainties are ignored.


Assuntos
Modelos Estatísticos , Praguicidas/química , Poluentes do Solo/química , Solo/química , Incerteza , Simulação por Computador , Método de Monte Carlo , Países Baixos , Sensibilidade e Especificidade , Movimentos da Água , Poluentes Químicos da Água/química
15.
Anal Chim Acta ; 706(1): 1-7, 2011 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-21995908

RESUMO

The aim of this paper is to show how it is possible to extract analytical information from images acquired with a flatbed scanner and make use of this information for real time control of a nickel plating process. Digital images of plated steel sheets in a nickel bath are used to follow the process under degradation of specific additives. Dedicated software has been developed for making the obtained results accessible to process operators. This includes obtaining the RGB image, to select the red channel data exclusively, to calculate the histogram of the red channel data and to calculate the mean colour value (MCV) and the standard deviation of the red channel data. MCV is then used by the software to determine the concentration of the additives Supreme Plus Brightner (SPB) and SA-1 (for confidentiality reasons, the chemical contents cannot be further detailed) present in the bath (these two additives degrade and their concentration changes during the process). Finally, the software informs the operator when the bath is generating unsuitable quality plating and suggests the amount of SPB and SA-1 to be added in order to recover the original plating quality.


Assuntos
Galvanoplastia , Níquel/química , Calibragem , Galvanoplastia/normas , Níquel/normas , Controle de Qualidade , Software , Espectrofotometria Ultravioleta
16.
Phytopathology ; 100(11): 1169-75, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20932165

RESUMO

Periodicity in host availability is common in agricultural systems. Although it is known to have profound effects on plant pathogen abundance, the evolutionary consequences of periodicity for the pathogen population have not previously been analyzed. An epidemiological model incorporating periodic absence of the host crop is combined with the theory of adaptive dynamics to determine whether or not seasonality in host presence plays a role in the occurrence of evolutionary branching, leading to coexisting yet genetically distinct pathogen phenotypes. The study is motivated and illustrated by the specific example of take-all disease of wheat, caused by the pathogen Gaeumannomyces graminis var. tritici, for which two coexisting but genetically distinct types and a trade-off related to seasonality in host presence have been identified. Numerical simulations are used to show that a trade-off between the pathogen transmission rate and the survival of the pathogen between cropping seasons cannot account for the evolutionary branching observed in many pathogens. Model elaborations show that this conclusion holds for a broad range of putative mechanisms. Although the analysis is motivated and illustrated by the specific example of take-all of wheat, the results apply to a broad range of pathogens.


Assuntos
Ascomicetos/genética , Evolução Biológica , Periodicidade , Simulação por Computador , Modelos Biológicos , Estações do Ano , Fatores de Tempo
17.
Proc Biol Sci ; 277(1688): 1735-42, 2010 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-20129975

RESUMO

Many pathogens transmit to new hosts by both infection (horizontal transmission) and transfer to the infected host's offspring (vertical transmission). These two transmission modes require specific adaptations of the pathogen that can be mutually exclusive, resulting in a trade-off between horizontal and vertical transmission. We show that in mathematical models such trade-offs can lead to the simultaneous existence of two evolutionary stable states (evolutionary bi-stability) of allocation of resources to the two modes of transmission. We also show that jumping between evolutionary stable states can be induced by gradual environmental changes. Using quantitative PCR-based estimates of abundance in seed and vegetative parts, we show that the pathogen of wheat, Phaeosphaeria nodorum, has jumped between two distinct states of transmission mode twice in the past 160 years, which, based on published evidence, we interpret as adaptation to environmental change. The finding of evolutionary bi-stability has implications for human, animal and other plant diseases. An ill-judged change in a disease control programme could cause the pathogen to evolve a new, and possibly more damaging, combination of transmission modes. Similarly, environmental changes can shift the balance between transmission modes, with adverse effects on human, animal and plant health.


Assuntos
Ascomicetos/fisiologia , Ascomicetos/patogenicidade , Evolução Biológica , Interações Hospedeiro-Patógeno/genética , Doenças das Plantas/microbiologia , Triticum/microbiologia , Adaptação Fisiológica , Animais , Ascomicetos/genética , Humanos , Modelos Genéticos , Folhas de Planta/microbiologia , Reação em Cadeia da Polimerase/métodos , Sementes/microbiologia , Triticum/genética
18.
Eur J Cancer ; 45(14): 2519-27, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19556122

RESUMO

PURPOSE: This study was performed to assess the toxicities, the maximum-tolerated dose (MTD), the pharmacokinetics and the anti-tumour activity of gemcitabine given by 24-h hepatic arterial infusion (HAI). PATIENTS AND METHODS: Patients with liver malignancies received gemcitabine by 24-h HAI, weekly x 3, every 4 weeks. On day 1 or day 8 of the first cycle, patients received one administration by 24-h intravenous infusion for pharmacokinetic comparison and to determine hepatic extraction. RESULTS: Thirteen patients received gemcitabine at the dose levels of 75, 135 and 180 mg/m(2). The MTD was 180 mg/m(2) with thrombocytopaenia as the dose-limiting toxicity. Pharmacokinetic analysis showed a significantly lower maximum gemcitabine plasma concentration (C(max): HAI, 26, 80 and 128 nM, respectively; IV, 229, 264 and 293 nM, respectively) and area under the plasma-concentration-versus-time curve (AUC(0-24h): HAI, 386, 1247 and 2033 nmol x h/L, respectively; IV, 3526, 4818 and 5363 nmol x h/L, respectively) during HAI, compared with intravenous infusion (both P<0.001). Additionally, the mean hepatic extraction ratios of gemcitabine at the 75, 135 and 180 mg/m(2) dose level were 0.89, 0.75 and 0.55, respectively. Hepatic extraction decreased linearly with increasing dose. The C(max) and AUC(0-24h) of 2',2'-difluoro-2'-deoxyuridine, the deaminated product of gemcitabine, were similar for HAI and intravenous infusion. Seven patients had stable disease for a median duration of 9 months (range: 2-11 months). CONCLUSIONS: Gemcitabine given by 24-h HAI was well tolerated and resulted in significantly lower systemic gemcitabine plasma concentrations than intravenous infusion due to a relatively high hepatic extraction.


Assuntos
Antimetabólitos Antineoplásicos , Desoxicitidina/análogos & derivados , Neoplasias Hepáticas , Adulto , Idoso , Antimetabólitos Antineoplásicos/administração & dosagem , Antimetabólitos Antineoplásicos/efeitos adversos , Antimetabólitos Antineoplásicos/farmacocinética , Desoxicitidina/administração & dosagem , Desoxicitidina/efeitos adversos , Desoxicitidina/farmacocinética , Feminino , Artéria Hepática , Humanos , Infusões Intra-Arteriais , Infusões Intravenosas , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/secundário , Masculino , Dose Máxima Tolerável , Pessoa de Meia-Idade , Trombocitopenia/etiologia , Resultado do Tratamento , Gencitabina
19.
Br J Radiol ; 82(973): e11-4, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19095808

RESUMO

We present a case of splenic artery embolisation (SAE) after traumatic splenic injury that was complicated by acute necrotizing pancreatitis, caused by inadvertently extensive embolisation of the splenic artery. Although SAE is increasingly used for splenic preservation in trauma, there is insufficient knowledge on its efficacy and pitfalls. This report aims to draw attention to a rare but potentially serious complication of SAE.


Assuntos
Embolização Terapêutica/efeitos adversos , Pancreatite Necrosante Aguda/etiologia , Baço/lesões , Artéria Esplênica/diagnóstico por imagem , Acidentes de Trânsito , Humanos , Masculino , Pessoa de Meia-Idade , Pancreatite Necrosante Aguda/diagnóstico por imagem , Baço/diagnóstico por imagem , Tomografia Computadorizada por Raios X
20.
Phytopathology ; 98(2): 239-49, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18943201

RESUMO

The basic reproduction number, R0, is defined as the total number of infections arising from one newly infected individual introduced into a healthy (disease-free) host population. R0 is widely used in ecology and animal and human epidemiology, but has received far less attention in the plant pathology literature. Although the calculation of R0 in simple systems is straightforward, the calculation in complex situations is challenging. A very generic framework exists in the mathematical and biomathematical literature, which is difficult to interpret and apply in specific cases. In this paper we describe a special case of this general framework involving the use of matrix population models. Leading by example, we explain the existing mathematical literature on this subject in such a way that plant pathologists can apply the method for a wide range of pathosystems.


Assuntos
Modelos Teóricos , Doenças das Plantas/virologia , Vírus de Plantas/fisiologia , Plantas/virologia , Interações Hospedeiro-Parasita , Dinâmica Populacional
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