References of "Nguyen, Bach Kim"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailHoney polyphenols extraction: method development and evidence of cis isomerization
Istasse, Thibaut ULg; Jacquet, Nicolas ULg; Berchem, Thomas ULg et al

in Analytical Chemistry Insights (2016), 11

Honey polyphenols have been studied with the objective of relating honeys to their floral sources. Initially synthesized by plant, these polyphenols can be found in the plant’s nectar, where they are ... [more ▼]

Honey polyphenols have been studied with the objective of relating honeys to their floral sources. Initially synthesized by plant, these polyphenols can be found in the plant’s nectar, where they are collected by bees which convert the nectar into honey. Consequently, polyphenols constitute minor honey components. The development of a solid phase extraction method for honey polyphenols is presented herein. The technique employs Amberlite XAD-2 adsorbent and was tested on monofloral honeys from six different plants: acacia, chestnut, eucalyptus, thyme, sunflower and wild carrot. Analyses were performed using high performance liquid chromatography coupled with UV detection and mass spectrometry. Several phenolic acids and flavonoids were identified: caffeic and p-coumaric acids, quercetin, kaempferol, naringenin, chrysin and pinocembrin. Generally, the quantity of a given polyphenol in the honey was around 0.2 mg/100g of honey, except for chestnut honey which contained around 3.0 mg of p-coumaric acid/100g of honey. Analyses highlighted significant formation of cis isomers for phenolic acids during the extraction despite protection from light. [less ▲]

Detailed reference viewed: 30 (7 ULg)
Full Text
See detailCaractérisation et étude du potentiel de valorisation des composés phénoliques de miels monofloraux
Istasse, Thibaut ULg; Nguyen, Bach Kim ULg; Richel, Aurore ULg

Conference (2016, January 20)

Présentation des recherches effectuées dans le cadre du travail de fin d'étude sur les composés phénoliques présents dans les miels monofloraux. Ces composés ont été extraits par extraction en phase ... [more ▼]

Présentation des recherches effectuées dans le cadre du travail de fin d'étude sur les composés phénoliques présents dans les miels monofloraux. Ces composés ont été extraits par extraction en phase solide et analysés par chromatographie liquide avec détection UV et spectrométrie de masse. [less ▲]

Detailed reference viewed: 11 (3 ULg)
Full Text
See detailAssessment of the species richness of highly eusocial bees according with habitat in Gabon
Fabre Anguilet, Edgard ULg; Bengone Ndong, Toussaint; Nguyen, Bach Kim ULg et al

Poster (2015, May 18)

Bees are among the most e ective pollinators. These insects include honeybee and stin- gless bee. In Africa, habitat loss is the main threat to these insects. This loss of habitat is largely due to ... [more ▼]

Bees are among the most e ective pollinators. These insects include honeybee and stin- gless bee. In Africa, habitat loss is the main threat to these insects. This loss of habitat is largely due to various human activities. An evaluation of the richness of social bees in three locaties in Gabon (Central Africa) was conducted from October 2013 to March 2014: Kougouleu who underwent deforestation and implantation of food crops, forest area Mas- sengalini in bu er zone of protected area of Lope and Lekokodiba in logging concession of Preccious Woods Gabon. For this, a collection was conducted using yellow traps lled with a mixture of water and honey and using a hand vacuum in 20 sites in each area. The number of species was compared to that estimated there are about thirty years. Eleven species of social bees (Apis mellifera adansonii and ten stingless bee species) were collected, of which 5 to Kougouleu, 8 to Massengalini and 11 to L ekokodiba. Honeybee has been collected in all localities. Forest localities are distinguished from Kougouleu by higher species diversity. This di erence is highly signi cant (Kruskal-Wallis 2 = 45.362, df = 2 and p-value<0.001). A decrease of approximately 50% of the number of stingless bee species in 30 years was found to Kougouleu, while the number of social bee species varies little in forest localities. Our study shows that the loss of forest habitat causes a decline in the species richness of social bees and stingless bees are more sensitive to this loss as the honeybee. [less ▲]

Detailed reference viewed: 63 (12 ULg)
Peer Reviewed
See detailMeliponini and Apini in Africa (Apidae: Apinae): a review on the challenges and stakes bound to their diversity and their distribution
Fabre Anguilet, Edgard ULg; Nguyen, Bach Kim ULg; Bengone Ndong, Toussaint et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2015), 19(4),

Introduction. Meliponini and Apini contribute to the pollination of flowering plants and to improving agricultural yields. These bees’ diversity, distribution and abundance depend on the ecosystem in ... [more ▼]

Introduction. Meliponini and Apini contribute to the pollination of flowering plants and to improving agricultural yields. These bees’ diversity, distribution and abundance depend on the ecosystem in which they evolve. The present work aims to summarize the diversity, distribution, abundance, potential threats, challenges and issues faced with respect to these social bees in Africa. Literature. In Africa, there were 21 species of Meliponini and 2 species of Apini (Apis). Aspects related to the species diversity, distribution, biology, ecology and abundance of nests are poorly documented, especially for Meliponini. This deficit could be related to a lack of interest of the authors or the various difficulties in performing these studies in Africa. With regard to the difficulties, there is a need to clarify the taxonomy of Meliponini, and the observation of nests in certain forest environments is difficult. Nest predation and habitat loss are the main threats that could cause the depopulation of certain social bee species in Africa. If there is currently new evidence that diseases and pests did not endanger these bees, then there is a need for further studies for better assessment of the risks that are associated with these potential threats. Conclusions. Work on the diversity, distribution and abundance of the social bees must be strengthened to address the challenges that are related to these insects in Africa. Indeed, this approach will contribute to answering the challenges of sustainable management of the biodiversity and economic and agricultural issues. [less ▲]

Detailed reference viewed: 119 (18 ULg)
Full Text
See detailEvaluation of two capture methods in the assessment of species richness of eusocial bees in Gabon
Fabre Anguilet, Edgard ULg; Bengone Ndong, Toussaint; Francis, Frédéric ULg et al

Poster (2014, December 13)

Detailed reference viewed: 23 (6 ULg)
Full Text
See detailHoney bee colony strength - Assessing accuracy of the Liebefeld estimation method
Leclercq, Gil ULg; Gengler, Nicolas ULg; Francis, Frédéric ULg et al

Poster (2014, December 12)

Honey bee colony strength (number of adult bees in a colony) is a crucial character used for both breeding and research. In breeding programs a rough estimate is usually sufficient to select strong ... [more ▼]

Honey bee colony strength (number of adult bees in a colony) is a crucial character used for both breeding and research. In breeding programs a rough estimate is usually sufficient to select strong colonies. On the other hand, the accuracy of this character can deeply affect the quality of several studies in both fundamental and applied research. For example these studies are related to the assessment of low demographic variations following a stress, or the estimate of a host-parasite ratio (e.g. involving the mite Varroa destructor Anderson & Trueman). The “Liebefeld estimation method” is extensively used in these studies while its accuracy remains weakly documented. Our goal is to provide more information on the accuracy of this method. [less ▲]

Detailed reference viewed: 134 (5 ULg)
Full Text
Peer Reviewed
See detailPhysico-chemical properties and aroma profile of Acacia Honey produced in Romania
Madas, Mariana-Niculina ULg; Francis, Frédéric ULg; Marghitas, L.A. et al

in Communications in Agricultural and Applied Biological Sciences (2014, February 07), 79(1), 133-135

Detailed reference viewed: 178 (17 ULg)
Full Text
See detailLa mortalité de l'abeille domestique : entre communication médiatique et scientifique
Leclercq, Gil ULg; Francis, Frédéric ULg; Haubruge, Eric ULg et al

Conference given outside the academic context (2013)

A l’heure actuelle, plus personne n’ignore que nos populations d’abeilles domestiques subissent de lourdes pertes, chez nous comme dans de nombreux autres pays. Les médias ont axés leur communication sur ... [more ▼]

A l’heure actuelle, plus personne n’ignore que nos populations d’abeilles domestiques subissent de lourdes pertes, chez nous comme dans de nombreux autres pays. Les médias ont axés leur communication sur des messages très simples. On en retient surtout que les pesticides tuent nos abeilles. La conclusion au problème est dès lors évidente : il faut interdire les pesticides. Mais cette problématique est-elle si simple ? Ce message est-il le même que celui communiqué par les scientifiques ? Cette conférence permettra de faire le point sur les pertes en colonies d’abeilles domestiques. On s’intéressera plus particulièrement aux pertes de ces dernières années en Belgique, cartes et chiffres à l’appui. On y verra aussi comment chacun, qu’il soit citoyen, apiculteur, agriculteur,… peut aider à enrayer cette mortalité effrayante. [less ▲]

Detailed reference viewed: 142 (17 ULg)
Full Text
Peer Reviewed
See detailStandard epidemiological methods to understand and improve Apis mellifera health
vanEngelsdorp, D; Lengerich, E; Spleen, A et al

in Journal of Apicultural Research (2013), 52(1),

Detailed reference viewed: 34 (2 ULg)
Full Text
Peer Reviewed
See detailHydroxymethylfurfural: a possible emergent cause of honey bee mortality?
Zirbes, Lara ULg; Nguyen, Bach Kim ULg; de Graaf, DC et al

in Journal of Agricultural and Food Chemistry (2013), 61(49), 11865-11870

Detailed reference viewed: 28 (6 ULg)
Full Text
See detailDiversité de l’abeille & sélection de souches tolérantes à Varroa destructor
Leclercq, Gil ULg; Francis, Frédéric ULg; Haubruge, Eric ULg et al

Conference given outside the academic context (2012)

Présentation des 2 volets de recherche du projet "Selapis" (D31-1280) : la diversité de l'abeille et la sélection de souches tolérantes au Varroa

Detailed reference viewed: 106 (18 ULg)
Full Text
See detailEvaluation of the genetic diversity of honey bees, Apis mellifera L. in the Walloon Region and selection of strains tolerant to the mite Varroa destructor Anderson and Trueman
Leclercq, Gil ULg; Nguyen, Bach Kim ULg; Gengler, Nicolas ULg et al

Poster (2012, February 10)

For more than a decade, high losses of honey bee colonies have been noticed in several countries, including Belgium. Currently often the mite Varroa destructor is considered a main threat for beekeeping ... [more ▼]

For more than a decade, high losses of honey bee colonies have been noticed in several countries, including Belgium. Currently often the mite Varroa destructor is considered a main threat for beekeeping. In view of the inefficiency of the current chemical treatments, one of the solutions is to select honey bees tolerant to this parasite using genomic selection. To reach this objective the genetic diversity of honey bees needs first to be studied using mainly ‘Single Nucleotide Polymorphisms’ (SNP). Records and samples will be collected all over the Walloon Region in order to create an informative phenotypic and genomic data base that will be used for ‘Genome Wide Association Studies’ (GWAS) to detect associations between SNPs and tolerance, and to select bees tolerant to Varroa destructor. [less ▲]

Detailed reference viewed: 311 (28 ULg)
Full Text
Peer Reviewed
See detailCalculating and Reporting Managed Honey Bee Colony Losses
vanEngelsdorp, Dennis; Brodschneider, Robert; Brostaux, Yves ULg et al

in Yoder, Jay (Ed.) Honey Bee Colony Health (2011)

Detailed reference viewed: 95 (5 ULg)
Full Text
Peer Reviewed
See detailHoney bee colony losses in Belgium during the 2008-9 winter
Nguyen, Bach Kim ULg; Mignon, Jacques ULg; Laget, Dries et al

in Journal of Apicultural Research (2010), 49(4), 337-339

Detailed reference viewed: 107 (11 ULg)
See detailAssociation des approches morphologique et moléculaire pour l’identification des vers à soies endémiques de Madagascar (Lasiocampidae, Borocera cajani)
Rakotondramanana, Alihasina; Nguyen, Bach Kim ULg; Verheggen, François ULg et al

Poster (2010, July)

La soie est une matière utilisée par les Malgaches depuis bien avant la colonisation. Cette soie est fabriquée à partir de la collecte de cocons des papillons du genre Borocera spp., ver à soie sauvage ... [more ▼]

La soie est une matière utilisée par les Malgaches depuis bien avant la colonisation. Cette soie est fabriquée à partir de la collecte de cocons des papillons du genre Borocera spp., ver à soie sauvage. On connaît une dizaine d’espèces de vers à soie sauvages endémiques à Madagascar. Ces lépidoptères polyphages se nourrissent surtout des feuilles de Uapaca bojeri et d’autres plantes telles que Dodonea madagascariensis et Psidium guyava. Les critères morphologiques se révèlent insuffisant pour identifier cette diversité d’espèces de vers à soie, surtout au niveau des stades immatures. Afin de pallier à cette incapacité d’identifier les espèces, des méthodes de marqueurs moléculaires, en particulier la RAPD (Random Amplified Polymorphic DNA) et iSSR (inter Simple Sequence Repeat), ont été appliquées. En plus de l’identification des espèces, une étude de la diversité et de la distribution des vers à soie suite à la collecte dans plusieurs forêts éloignées de plusieurs de kilomètres les unes des autres (Arivonimamo, Ambatofinandrahana, Antananarivo). Cette étude a été menée dans le cadre de la conservation de ces espèces de vers à soie endémiques en milieu. Afin d’augmenter durablement les populations de vers à soie endémiques dans les forêts de Uapaca, il est important de déterminer les espèces en présence et les capacités de dispersion de ces dernières. Les techniques d’identification moléculaires développées permettront d’orienter les stratégies de gestion des populations de Borocera et des méthodes de gestion de l’écosystème, appropriables par les gestionnaires et les communautés locales des la forêt à Uapaca bojeri. [less ▲]

Detailed reference viewed: 106 (22 ULg)
See detailLe point sur les causes des pertes d'abeilles domestiques en Région Wallonne
Nguyen, Bach Kim ULg; Mignon, Jacques ULg; Widart, Joëlle ULg et al

Conference given outside the academic context (2010)

Detailed reference viewed: 135 (33 ULg)
See detailRéponses aux questions que l'on se pose sur la mortalité des abeilles domestiques en Belgique
Nguyen, Bach Kim ULg; Mignon, Jacques ULg; Saegerman, Claude ULg et al

Conference given outside the academic context (2010)

Detailed reference viewed: 74 (21 ULg)