References of "Ziemons, Eric"
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See detailPoplar-root-knot nematode interaction: a model for perennial woody species
Baldacci-Cresp, Fabien; Sacre, Pierre-Yves ULg; Twyffels, Laure et al

in Molecular Plant-Microbe Interactions [=MPMI] (in press)

Plant root-knot nematode interaction studies are performed on several host plant models. However, even though root-knot nematodes interact with trees, no perennial woody model has been explored so far. We ... [more ▼]

Plant root-knot nematode interaction studies are performed on several host plant models. However, even though root-knot nematodes interact with trees, no perennial woody model has been explored so far. We show here that poplar (Populus tremula x Populus alba) grown in vitro is susceptible to Meloidogyne incognita as this nematode is able to penetrate, to induce feeding sites and to reproduce in poplar roots. As analyzed by Raman spectromicroscopy, the cell walls of the giant cells, with typical characteristics of transfer cell walls, were not lignified and were composed mainly of pectin and cellulose. To better depict the poplar-nematode interaction at the molecular level, a quantitative RT-PCR analysis was performed to study changes in poplar gene expression in galls compared to non-infected roots. Three marker genes, reported for other plant hosts, including expansin A, histone 3.1 and asparagine synthase, were conserved for poplar-nematode interaction. In addition, the down-regulation of four genes coding for enzymes of the lignin biosynthesis pathway was evidenced in galls, suggesting a modification in lignin composition within galls developed in poplar roots. Together, this study shows that poplar is a suitable model host for specific traits of tree-nematode interaction. [less ▲]

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See detailA simple calibration approach based on film-casting for confocal Raman microscopy to support the development of a Hot-Melt Extrusion process
Netchacovitch, Lauranne ULg; Thiry, Justine ULg; De Bleye, Charlotte ULg et al

in Talanta (2016), 154

When developing a new formulation, the development, calibration and validation steps of analytical methods based on vibrational spectroscopy are time-consuming. For each new formulation, real samples must ... [more ▼]

When developing a new formulation, the development, calibration and validation steps of analytical methods based on vibrational spectroscopy are time-consuming. For each new formulation, real samples must be produced and a “reference method” must be used in order to determine the Active Pharmaceutical Ingredient (API) content of each sample. To circumvent this issue, the paper presents a simple approach based on the film-casting technique used as a calibration tool in the framework of hot-melt extrusion process. Confocal Raman microscopic method was successfully validated for the determination of itraconazole content in film-casting samples. Then, hot-melt extrusion was carried out to produce real samples in order to confront the results obtained with confocal Raman microscopy and Ultra High Performance Liquid Chromatography (UHPLC). The agreement between both methods was demonstrated using a comparison study based on the Bland and Altman’s plot. [less ▲]

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See detailMOISTURE CONTENT DETERMINATION OF FREEZE-DRIED PRODUCTS BY NEAR-INFRARED SPECTROSCOPY: A CASE STUDY FOR UNIVERSAL REGRESSION MODEL
Clavaud, Matthieu ULg; Roggo, Yves; Degardin, Klara et al

Poster (2016, June 06)

Karl Fischer titration is the reference method for moisture content determination in the pharmaceutical industry. Near-infrared spectroscopy is considered the most suitable alternative technique. Indeed ... [more ▼]

Karl Fischer titration is the reference method for moisture content determination in the pharmaceutical industry. Near-infrared spectroscopy is considered the most suitable alternative technique. Indeed, NIRS is a safe and fast method which does not require sample preparation. Nevertheless, the development and validation phases are time-consuming. In addition, the NIRS methods presented so far were mostly product specific. The main objective of this study is to highlight that an universal calibration model can be validated for several freeze-dried products in order to speed up the validation time. This objective was led in two steps. A universal model was first evaluated. A calibration set and a validation set were built up with three freeze-dried products. An antibody drug conjugate, a large molecule and a small molecule all packed in sealed vials were used to introduce more variability. Regression methods were then compared in order to optimize the prediction values. [less ▲]

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See detailFrom Near-Infrared and Raman to Surface-Enhanced Raman Spectroscopy: Progress, Limitations, Perspectives in Bioanalysis
Dumont, Elodie ULg; De Bleye, Charlotte ULg; Sacre, Pierre-Yves ULg et al

in Bioanalysis (2016), 8(10), 1077-1103

Over recent decades, spreading environmental concern entailed the expansion of green chemistry analytical tools. Vibrational spectroscopy, belonging to this class of analytical tool, is particularly ... [more ▼]

Over recent decades, spreading environmental concern entailed the expansion of green chemistry analytical tools. Vibrational spectroscopy, belonging to this class of analytical tool, is particularly interesting taking into account its numerous advantages such as fast data acquisition and no sample preparation. In this context, Near-Infrared, Raman and mainly Surface-Enhanced Raman Spectroscopy (SERS) have thus gained interest in many fields including bioanalysis. The two former techniques only ensure the analysis of concentrated compounds in simple matrices, whereas the emergence of SERS improved the performances of vibrational spectroscopy to very sensitive and selective analyses. Complex SERS substrates were also developed enabling biomarker measurements, paving the way for SERS immunoassays. Therefore, in this paper, the strengths and weaknesses of these techniques will be highlighted with a focus on recent progress. [less ▲]

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See detailAnalytical Tools and Strategic Approach to Detect Poor Quality Medicines, Identify Unknown Components, and Timely Alerts for Appropriate Measures: Case Study of Antimalarial Medicines
Habyalimana, Védaste ULg; Mbinze Kindenge, Jérémie; Kalenda Tshilombo, Nicodème ULg et al

in American Journal of Analytical Chemistry (2015), 6

Nowadays, the circulation of poor quality medicines is becoming an alarming worldwide phenomenon with serious public health and socio-economic concerns. The situation is particularly critical in ... [more ▼]

Nowadays, the circulation of poor quality medicines is becoming an alarming worldwide phenomenon with serious public health and socio-economic concerns. The situation is particularly critical in developing countries where drug quality assurance and regulatory systems for drug manufacturing, importation, distribution and sales are weak. A sustained vigilance on poor quality medicines that regroup counterfeit/falsified, substandard and degraded medicines is therefore required to ensure patient safety and genuine medicines integrity. A case situation is illustrated including a strategic approach and analytical tools that were found useful to detect poor quality medicines, identify unknown components, and timely alerts for appropriate measures against the spread of those harmful products. Several suspected medicines randomly sampled in several strategic Rwandan areas were firstly check-controlled by means of visual inspection and then applying several analytical techniques from simple to more complex ones. The following medicines were studied: quinine sulfate tablets, artemisinin-based combination tablets, and artesunate powders for injection. Taking into account the pharmaceutical forms and the chemical characteristics, the following tests were applied: uniformity of mass, friability, disintegration, fluorescence, identification and assay. They were followed by more complex analytical techniques that allowed more comprehension of abnormal findings among which the presence of a wrong active pharmaceutical ingredient in quinine sulfate tablets which is mainly discussed in this paper to illustrate a strategic approach and various analytical tools that can be used in detecting and identifying unknown component in poor quality medicines. [less ▲]

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See detailPour analyser la qualité des médicaments
Ziemons, Eric ULg

E-print/Working paper (2015)

Technique permettant de décortiquer les caractéristiques chimiques et physiques des molécules, la spectroscopie vibrationnelle est précieuse dans le domaine pharmaceutique. Les chercheurs du laboratoire ... [more ▼]

Technique permettant de décortiquer les caractéristiques chimiques et physiques des molécules, la spectroscopie vibrationnelle est précieuse dans le domaine pharmaceutique. Les chercheurs du laboratoire de Chimie Analytique de l’Université de Liège, spécialistes dans ce domaine de recherche, collaborent régulièrement avec des entreprises pharmaceutiques pour contrôler leurs matières premières, produits finis et procédés. [less ▲]

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See detailA simple approach for ultrasensitive detection of bisphenols by multiplexed surface-enhanced Raman scattering
De Bleye, Charlotte ULg; Dumont, Elodie ULg; Hubert, Cédric ULg et al

in Analytica Chimica Acta (2015), 888

Bisphenol A (BPA) is well known for its use in plastic manufacture and thermal paper production despite its risk of health toxicity as an endocrine disruptor in humans. Since the publication of new ... [more ▼]

Bisphenol A (BPA) is well known for its use in plastic manufacture and thermal paper production despite its risk of health toxicity as an endocrine disruptor in humans. Since the publication of new legislation regarding the use of BPA, manufacturers have begun to replace BPA with other phenolic molecules such as bisphenol F (BPF) and bisphenol B (BPB), but there are no guarantees regarding the health safety of these compounds at this time. In this context, a very simple, cheap and fast surface-enhanced Raman scattering (SERS) method was developed for the sensitive detection of these molecules in spiked tap water solutions. Silver nanoparticles were used as SERS substrates. An original strategy was employed to circumvent the issue of the affinity of bisphenols for metallic surfaces and the silver nanoparticles surface was functionalized using pyridine in order to improve again the sensitivity of the detection. Semi-quantitative detections were performed in tap water solutions at a concentrations range from 0.25 to 20 µg L-1 for BPA and BPB and from 5 to 100 µg L-1 for BPF. Moreover, a feasibility study for performing a multiplex-SERS detection of these molecules was also performed before successfully implementing the developed SERS method on real samples. [less ▲]

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See detailDevelopment of a simple approach for ultrasensitive detection of bisphenols by multiplexed surface enhanced Raman scattering
De Bleye, Charlotte ULg; Dumont, Elodie ULg; Netchacovitch, Lauranne ULg et al

Poster (2015, July 13)

A very simple, cheap and fast SERS method using functionalized silver nanoparticles was developed to detect bisphenols. This method was applied for the semi-quantitative detection of bisphenol A (BPA ... [more ▼]

A very simple, cheap and fast SERS method using functionalized silver nanoparticles was developed to detect bisphenols. This method was applied for the semi-quantitative detection of bisphenol A (BPA), bisphenol B (BPB) and bisphenol F (BPF) separately. Afterwards, a feasibility study of performing a multiplex SERS detection of BPA, BPB and BPF was successfully carried out. Finally, this developed method was applied on real samples which were solutions comprising cash receipts collected from different stores. [less ▲]

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See detailDevelopment, validation and comparison of NIR and Raman methods for the identification and assay of poor-quality oral quinine drops.
Mbinze Kidenge, Jérémie; Sacre, Pierre-Yves ULg; Yemoa, Achille et al

in Journal of Pharmaceutical & Biomedical Analysis (2015), 111

Poor quality antimalarial drugs are one of the public’s major health problems in Africa. The depth of this problem may be explained in part by the lack of effective enforcement and the lack of efficient ... [more ▼]

Poor quality antimalarial drugs are one of the public’s major health problems in Africa. The depth of this problem may be explained in part by the lack of effective enforcement and the lack of efficient local drug analysis laboratories. To tackle part of this issue, two spectroscopic methods with the ability to detect and to quantify quinine dihydrochloride in children’s oral drops formulations were developed and validated. Raman and Near Infrared (NIR) spectroscopy were selected for the drug analysis due to their low cost, non-destructive and rapid characteristics. Both of the methods developed were successfully validated using the total error approach in the range of 50-150% of the target concentration (20% W/V) within the 10% acceptance limits. Samples collected on the Congolese pharmaceutical market were analyzed by both techniques to detect potentially substandard drugs. After a comparison of the analytical performance of both methods, it has been decided to implement the method based on NIR spectroscopy to perform the routine analysis of quinine oral drop samples in the Quality Control Laboratory of Drugs at the University of Kinshasa (DRC). [less ▲]

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