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Lima S.S.S.,Federal University of Minas Gerais | Nobre V.,Federal University of Minas Gerais | de Castro Romanelli R.M.,Federal University of Minas Gerais | Clemente W.T.,Federal University of Minas Gerais | And 4 more authors.
Annals of Hematology | Year: 2016

Febrile neutropenia (FN) requires immediate use of antibiotics (ATB), and procalcitonin (PCT) is proven to be useful in guiding antibiotic therapy in different settings. This study investigated the use of PCT as a guide for the duration of ATB in FN. A randomized controlled trial was carried out from January–December 2010. A total of 62 hematological adult patients with FN were randomized, in 1:1 ratio, into two groups: (1) PCT group: length of ATB guided by institutional protocol plus PCT dynamics, and (2) control group: duration of ATB in accordance with institutional protocol. There was no difference between groups regarding the use of ATB for the first episode of fever (HR 1.14, 95 % CI 0.66–1.95, p = 0.641), with equivalent median duration of ATB therapy (PCT group 9.0 days and control group 8.0 days, p = 0.67), and median number of days without ATB (0 days, IQR 0–2 days for both groups, p = 0.96). We observed no difference in clinical cure rate (p = 0.68), infection relapse (p = 1.0), superinfection (p = 0.85), length of hospitalization (p = 0.64), and mortality at 28 days (p = 0.39) and at 90 days (p = 0.72). Considering the cut-off of 0.5 ng/ml, PCT was correlated with bacteremia (sensitivity of 51.9 % and specificity of 76.5 %). In this randomized controlled trial, adding a PCT-guided protocol to the standard recommendations did not reduce the use of antibiotics in febrile neutropenia, although no apparent harm was caused. PCT proved to be a marker of bacteremia in this setting. © 2016, Springer-Verlag Berlin Heidelberg.


Crauwels S.,De Nayer Institute | Zhu B.,Catholic University of Leuven | Steensels J.,Catholic University of Leuven | Busschaert P.,De Nayer Institute | And 7 more authors.
Applied and Environmental Microbiology | Year: 2014

Brettanomyces yeasts, with the species Brettanomyces (Dekkera) bruxellensis being the most important one, are generally reported to be spoilage yeasts in the beer and wine industry due to the production of phenolic off flavors. However, B. bruxellensis is also known to be a beneficial contributor in certain fermentation processes, such as the production of certain specialty beers. Nevertheless, despite its economic importance, Brettanomyces yeasts remain poorly understood at the genetic and genomic levels. In this study, the genetic relationship between more than 50 Brettanomyces strains from all presently known species and from several sources was studied using a combination of DNA fingerprinting techniques. This revealed an intriguing correlation between the B. bruxellensis fingerprints and the respective isolation source. To further explore this relationship, we sequenced a (beneficial) beer isolate of B. bruxellensis (VIB X9085; ST05.12/22) and compared its genome sequence with the genome sequences of two wine spoilage strains (AWRI 1499 and CBS 2499). ST05.12/22 was found to be substantially different from both wine strains, especially at the level of single nucleotide polymorphisms (SNPs). In addition, there were major differences in the genome structures between the strains investigated, including the presence of large duplications and deletions. Gene content analysis revealed the presence of 20 genes which were present in both wine strains but absent in the beer strain, including many genes involved in carbon and nitrogen metabolism, and vice versa, no genes that were missing in both AWRI 1499 and CBS 2499 were found in ST05.12/22. Together, this study provides tools to discriminate Brettanomyces strains and provides a first glimpse at the genetic diversity and genome plasticity of B. bruxellensis. © 2014, American Society for Microbiology.


PubMed | Federal University of Minas Gerais and De Nayer Institute
Type: Journal Article | Journal: Annals of hematology | Year: 2016

Febrile neutropenia (FN) requires immediate use of antibiotics (ATB), and procalcitonin (PCT) is proven to be useful in guiding antibiotic therapy in different settings. This study investigated the use of PCT as a guide for the duration of ATB in FN. A randomized controlled trial was carried out from January-December 2010. A total of 62 hematological adult patients with FN were randomized, in 1:1 ratio, into two groups: (1) PCT group: length of ATB guided by institutional protocol plus PCT dynamics, and (2) control group: duration of ATB in accordance with institutional protocol. There was no difference between groups regarding the use of ATB for the first episode of fever (HR 1.14, 95% CI 0.66-1.95, p=0.641), with equivalent median duration of ATB therapy (PCT group 9.0days and control group 8.0days, p=0.67), and median number of days without ATB (0days, IQR 0-2days for both groups, p=0.96). We observed no difference in clinical cure rate (p=0.68), infection relapse (p=1.0), superinfection (p=0.85), length of hospitalization (p=0.64), and mortality at 28days (p=0.39) and at 90days (p=0.72). Considering the cut-off of 0.5ng/ml, PCT was correlated with bacteremia (sensitivity of 51.9% and specificity of 76.5%). In this randomized controlled trial, adding a PCT-guided protocol to the standard recommendations did not reduce the use of antibiotics in febrile neutropenia, although no apparent harm was caused. PCT proved to be a marker of bacteremia in this setting.


Farkas L.,Lms International | Moens D.,De Nayer Institute | Donders S.,Lms International | Vandepitte D.,Catholic University of Leuven
Mechanical Systems and Signal Processing | Year: 2012

This paper deals with the design and optimisation for crashworthiness of a vehicle bumper subsystem, which is a key scenario for vehicle component design. The automotive manufacturers and suppliers have to find optimal design solutions for such subsystems that comply with the conflicting requirements of the regulatory bodies regarding functional performance (safety and repairability) and regarding the environmental impact (mass). For the bumper design challenge, an integrated methodology for multi-attribute design engineering of mechanical structures is set up. The integrated process captures the various tasks that are usually performed manually, this way facilitating the automated design iterations for optimisation. Subsequently, an optimisation process is applied that takes the effect of parametric uncertainties into account, such that the system level of failure possibility is acceptable. This optimisation process is referred to as possibility-based design optimisation and integrates the fuzzy FE analysis applied for the uncertainty treatment in crash simulations. This process is the counterpart of the reliability-based design optimisation used in a probabilistic context with statistically defined parameters (variabilities). © 2011 Elsevier Ltd.


Moens D.,De Nayer Institute | Hanss M.,University of Stuttgart
Finite Elements in Analysis and Design | Year: 2011

The objective of this paper is to give a general overview of recent research activities on non-probabilistic finite element analysis and its application for the representation of parametric uncertainty in applied mechanics. The overview focuses on interval as well as fuzzy uncertainty treatment in finite element analysis. Since the interval finite element problem forms the core of a fuzzy analysis, the paper first discusses the problem of finding output ranges of classical deterministic finite element problems where uncertain physical parameters are described by interval quantities. Different finite element analysis types will be considered. The paper gives an overview of the current state-of-the-art of interval techniques available from literature, focussing on methodological as well as practical aspects of the presented methods when their application in an industrial context is envisaged. Their possible value in the framework of applied mechanics is discussed as well. The paper then gives an overview of recent developments in the extension of the interval methods towards fuzzy finite element analysis. Recent developments in the framework of the transformation method as well as optimisation-based procedures are discussed. Finally, the paper concentrates specifically on implementation strategies for the application of the interval and fuzzy finite element method to large FE problems. © 2010 Elsevier B.V. All rights reserved.


Van Hooreweder B.,Catholic University of Leuven | Moens D.,De Nayer Institute | Boonen R.,Catholic University of Leuven | Kruth J.-P.,Catholic University of Leuven | Sas P.,Catholic University of Leuven
Advanced Engineering Materials | Year: 2012

This paper describes and analyzes fracture toughness and crack propagation of selective laser molten (SLM) components made from Ti6Al4V powder particles. The main goal of this research is to gain more insight in the fracture mechanisms of this relatively new material and to improve the static and dynamic behavior of cracked SLM-Ti components. At first, the SLM process parameters are optimized until the relative material density equals 99.7%. This is close to the relative density of vacuum arc remelted mill annealed standard oxygen titanium which is used as a reference for all experiments. A distinctive difference in phase morphology and texture of the microstructure is noticed between the SLM and the reference titanium. The fine acicular martensite phase of the SLM-Ti results in more brittle behavior and inferior fracture toughness. On the other hand, the fine grained microstructure leads to a large number of grain boundaries acting as obstacle points for crack propagation. Consequently, crack growth properties do not significantly differ between both. Microstructural analysis of the crack growth and final failure areas on the fractured surfaces is performed to study the failure mechanisms in more detail. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Jacobs W.,Catholic University of Leuven | Boonen R.,Catholic University of Leuven | Sas P.,Catholic University of Leuven | Moens D.,De Nayer Institute
Mechanical Systems and Signal Processing | Year: 2014

This paper experimentally investigates the formation of a lubricant film in a deep groove ball bearing and its effect on the bearing dynamics. A novel test rig is introduced, which allows testing different types and sizes of bearings in real-life conditions. The test rig dynamics are optimised such that the dynamic properties of the bearing are measured in a frequency range below the resonances of the flexible modes. Two properties of the bearing, both its stiffness and damping value in the direction of the static bearing load, are identified. The behaviour of the lubricant film between the rolling elements and raceways is measured based on the electrical resistance through the bearing. For this purpose, the bearing housing is electrically isolated from the surrounding structure. The electrical resistance, stiffness and damping of the test bearing are identified during a speed run-up. The influence of the bearing temperature is analysed as well. During a run-up at constant bearing temperature, the measurement of the electrical resistance describes the formation of the lubricant film. Due to the formation of the lubricant film, the bearing stiffness increases by 3.2% while the damping increases by 24%. During a warm-up of the bearing, the viscosity of the lubricant film decreases strongly. A resulting decrease in electrical resistance, stiffness and damping is measured. Finally, the electrical resistance, stiffness and damping are identified at different speeds, after the bearing has reached a stable temperature at each speed. A combined effect of both rotation and temperature is observed and discussed. © 2013 Elsevier Ltd. All rights reserved.


Vandepitte D.,Catholic University of Leuven | Moens D.,De Nayer Institute
Applied Mechanics and Materials | Year: 2012

Development of a complicated technical problem encompasses different successive decisions that are based on techical analysis and engineering judgment. In each of these steps, some degree of non-determinism is inevitable. The paper discusses different types of non-deterministic parameters that may be relevant in different stages of engineering analysis. The entire cycle of development of a product is considered, and it is shown that the relevance of methods is different in different stages of the development cycle. A classification of different types of non-deterministic properties is presented. Based on the nature of these different classes of model properties, it is discussed to what degree each of these fits in the framework of either a probabilistic or a non-probabilistic concept. The availability of realistic data in an appropriate format is another issue that should be taken into account. A validated probabilistic representation is usually only possible after an extensive campaign of data acquisition has been conducted, or at least after sufficient data have been collected to allow for a reliable estimation of a statistical model. A study of scientific literature shows that validated information is not always available. A general conclusion is that probabilistic methods are applicable in later stages of development, when a sufficiently large database of product data has been gathered. Probabilistic approaches are perfectly suited for conditions when the product is already in service. Possibilistic analysis on the other hand is best suited for application in cases when the data set about the product at hand is still incomplete. © (2012) Trans Tech Publications, Switzerland.


Hooreweder B.V.,Catholic University of Leuven | Moens D.,De Nayer Institute | Boonen R.,Catholic University of Leuven | Sas P.,Catholic University of Leuven
Fatigue and Fracture of Engineering Materials and Structures | Year: 2012

This paper provides new insights in the use of the critical distance method for fatigue analysis of notched aluminium components subjected to constant amplitude bending loading. A straightforward test setup was developed to load test samples with different stress concentrations in repeated bending at high test frequency. The mean values of the local endurable stress amplitudes are determined with the staircase method and the Dixon and Mood theory using a minimum amount of test samples. The critical distance is determined using these fatigue limits and the corresponding stress gradients determined by means of finite element analysis. The results indicate a unique critical distance of 0.22 mm for fatigue crack initiation. Consequently, the critical distance theory can be successfully applied for fatigue analysis of notched specimens or engineering components of aluminium EN AW 7075 T7351 with geometrical features of various size and shape subjected to fluctuating loading in bending. © 2012 Blackwell Publishing Ltd.


Van Hooreweder B.,Catholic University of Leuven | Moens D.,De Nayer Institute | Boonen R.,Catholic University of Leuven | Sas P.,Catholic University of Leuven
International Conference on Noise and Vibration Engineering 2012, ISMA 2012, including USD 2012: International Conference on Uncertainty in Structure Dynamics | Year: 2012

This work describes the design, implementation and first results of a fatigue test rig capable of subjecting cylindrical specimens of different sizes and materials to complex real-life loading conditions. The resulting test rig can be used to combine a rotating bending load with a fluctuating torsional load. Due to a closed electromechanical loop, power consumption is limited and a maximum test frequency of 50Hz can be obtained for both the bending and the torsion. In addition, the optimal control strategy is determined using analytical techniques in order to simulate the test rig and to further reduce the power requirements for both electrical motors. Bending moments of 5-150 Nm can be combined with torsional moments of 5- 100 Nm at test frequencies between 2 and 50 Hz, leading to a significant advantage with respect to conventional fatigue testing techniques. In general, the presented test rig concept allows accelerated multi-axial fatigue tests on steel specimens, leading to a reduction of the time and cost needed for experimental validation of analytical and numerical fatigue calculations. Additionally, multi-axial fatigue criteria will be studied for different specimen sizes, geometries and materials. Furthermore, the test rig concept consists of conventional mechanical components making it relatively straightforward to implement and economically feasible. © (2012) by the Katholieke Universiteit Leuven Department of Mechanical Engineering All rights reserved.

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