Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Improved forensic hair evidence for drugs of abuse by mass spectrometry
    Duvivier, W.F. - \ 2016
    Wageningen University. Promotor(en): Michel Nielen, co-promotor(en): Teris van Beek. - Wageningen : Wageningen University - ISBN 9789462578159 - 194
    forensic science - hair - analytical methods - spectrometry - forensische wetenschap - haar - analytische methoden - spectrometrie

    Forensic hair analysis can be used as alternative evidence next to body fluids, and to obtain retrospective timeline information of an individual’s drug exposure. Chapter 1 describes the general concepts of drug incorporation into hair, external contamination, and the current status and limitations of hair analysis methods are introduced. Furthermore, an overview of ambient ionization techniques is given, with emphasis on direct analysis in real time (DART).
    The instrumentation, ionization mechanisms, and application range of DART are presented. Scientific challenges and objectives to improve forensic hair evidence are formulated, which formed the basis of the research presented in this thesis.

    A major issue in forensic hair analysis is the possibility of false-positive results due to external contamination. In Chapter 2, an evidence-based evaluation of decontamination protocols for the removal of cannabinoid contamination is presented, mainly focused on
    Δ9-tetrahydrocannabinol (THC). Different solvents were extensively tested for their ability to remove cannabinoid contamination originating from cannabis smoke or indirect contact with cannabis plant material. After selection of the most efficient solvents, different sequential wash steps were tested on externally contaminated blank hair samples. Finally, application of the three best performing protocols on cannabis users’ hair, both as such and after deliberate contamination, resulted in removal of all contamination without removing incorporated THC. From the detailed scientific evidence reported in this chapter, a protocol using a single methanol wash followed by a single aqueous SDS solution is recommended to remove external cannabis contamination.

    A novel approach for the analysis of intact locks of hair consisting of DART combined with high resolution mass spectrometry (HRMS) is developed in Chapter 3. DART–HRMS settings were optimized for the analysis of THC and the accuracy of the probed hair zone was investigated using spiked blank hair samples. Intact locks of hair could be longitudinally scanned without the need of extensive sample preparation, resulting in analysis times of only minutes. Detection of THC was achieved in several hair samples from cannabis users. A quantitative liquid chromatography (LC)–MS/MS method was developed, in-house validated, and used to confirm the presence of THC in drug user hair samples. With a retrospective timeline accuracy of ±2 weeks, a significant improvement over conventional segmented hair analysis was achieved. Moreover, differentiation between zones of different THC content within a DART hair scan could be made, indicating possibilities for retrospective assessment of time of drug use.

    The DART hair scan method has been improved and expanded in Chapter 4. Targeted detection of four commonly used drugs of abuse (amphetamine, cocaine, MDMA and THC) with structural confirmation was achieved by data-dependent product ion scans. Simultaneously,
    full-scan high-resolution data was obtained and retrospectively interrogated versus a list of more than a hundred, less common, drugs of abuse and occasionally abused pharmaceutical drugs. The hair scan method was validated for the analysis of cocaine against an accredited LC–MS/MS method and the detection limit for cocaine was found to comply with the cut-off value of 0.5 ng/mg. Hair samples of 10 different drug users were analyzed. Next to detection of the four targeted drugs of abuse, retrospective data interrogation revealed several additional hits. The detected substances correlated well with reported drug use and by the detection of several metabolites, drug use could be unambiguously proven. The retrospective timeline accuracy was further improved by use of a high spatial resolution DART exit cone, which yielded a DART spot size corresponding to approximately 10 days of hair growth.

    When direct and/or ambient ionization techniques are used to analyze intact hair samples, endogenous isobaric ions can overlap with compounds of interest and yield
    false-positive results. The selectivity of four MS instruments with different mass analyzers (orbitrap, quadrupole orbitrap, triple quadrupole, time-of-flight) was evaluated in Chapter 5 by DART analysis of THC from hair samples. To avoid overlap of THC with isobaric ions originating from the hair matrix, a mass resolution of at least 30,000 FWHM was necessary. The use of travelling wave ion mobility spectrometry (TWIMS) resulted in increased selectivity by separation of isobaric ions based on their drift times. A triple quadrupole instrument in multiple reaction monitoring (MRM) mode was found to have the best sensitivity, however, the used transitions were not specific enough for use on drug user hair samples. Thus the selectivity needed to indisputably differentiate THC from endogenous isobaric ions in drug user hair samples could only be achieved by the high resolution of the tested orbitrap MS instruments.

    Chapter 6 demonstrates the application of forensic hair analysis techniques to veterinary control. Timeline information could be obtained from veterinary hair samples. For this purpose, a UPLC–MS/MS hair analysis method was adapted and optimized for smaller sample sizes.
    After validation of the method, segmented hair samples obtained from clenbuterol-treated calves using the forensic hair sampling protocol were analyzed and clenbuterol concentration profiles along the hair samples could be obtained. Assessment of the average growth rate of calf tail hair enabled retrospective determination of time of clenbuterol administration.
    The estimated time of administration was reproducible when analyzing sub-samples taken from the same lock of hair and duplicate locks of hair, and in good correlation with the actual treatment.

    Through the research presented in this thesis, novel approaches in hair analysis have been developed and the value of forensic hair evidence improved considerably. In Chapter 7, the main achievements of this thesis are discussed in detail and an insight in the future perspectives of hair analysis and ambient ionization is given. Potential further applications of the DART hair scan method, and ambient ionization in general, are presented, including some preliminary results of new decontamination strategies, hair analysis possibilities, and other forensic uses of DART ionization.

    Plants4Cosmetics : perspectives for plant ingredients in cosmetics
    Boeriu, C.G. - \ 2015
    Wageningen : Wageningen UR - Food & Biobased Research (Report / Wageningen UR Food & Biobased Research 1603) - 38
    cosmetics - plants - flavonoids - phenols - pigments - plant pigments - polysaccharides - geranium - hyacinthus - chrysanthemum - orchidaceae - skin - hair - oil plants - medicinal plants - natural products - biobased chemicals - biobased economy - cosmetica - planten - flavonoïden - fenolen - pigmenten - plantenpigmenten - polysacchariden - geranium - hyacinthus - chrysanthemum - orchidaceae - huid - haar - olieleverende planten - medicinale planten - natuurlijke producten - chemicaliën uit biologische grondstoffen - biobased economy
    In opdracht van Bio Base Westland en de TKI Tuinbouw Koepel PPS Plantenstoffen, heeft Wageningen UR – Food & Biobased Research een exploratieve desktop studie uitgevoerd gericht op de identificatie van veelbelovende routes voor de valorisatie van plantinhoudstoffen - waaronder ook reststromen uit de tuinbouw - voor de cosmetische industrie. Een uitgebreide analyse van de beschikbare informatie werd uitgevoerd om de mogelijkheden voor de Nederlandse tuinbouwsector te bepalen. Er is gekeken naar marktkansen in de cosmetische industrie met inbegrip van natuurlijke en biologische ingrediënten.
    Hamsterharen: bron van informatie
    Teeffelen, A.J.A. van; Apeldoorn, R.C. van; Verkem, S. - \ 2001
    Zoogdier 12 (2001)1. - ISSN 0925-1006 - p. 11 - 14.
    cricetus cricetus - monitoring - detectie - vallen - kleefvallen - haar - animal burrows - hamsters - cricetus cricetus - monitoring - detection - traps - sticky traps - hair - animal burrows - hamsters
    Beschrijving van een nieuwe techniek voor hamsterburchtinventarisaties: met een haarval kan onderzocht worden of de burcht door hamsters bewoond wordt of niet
    Hair coat characteristics in Friesian heifers in the Netherlands and Kenya : experimental data and a review of literature
    Udo, H.M.J. - \ 1978
    Landbouwhogeschool Wageningen. Promotor(en): P. Hoekstra. - Wageningen : Veenman - 136
    lichaamstemperatuur - regulatie van de lichaamstemperatuur - rundvee - haar - kenya - nederland - ruggengraat - thermoregulatie - body temperature - body temperature regulation - cattle - hair - kenya - netherlands - spine - thermoregulation

    The export of about 2600 Friesian heifers to Kenya between 1971-1973 provided an opportunity of studying the adaptation problems experienced by these heifers. Within the framework of the NUFFIC (Netherlands Universities Foundation for International Cooperation) a research project entitled 'Adaptation of Dutch Friesian heifers in the Tropics, with special reference to Kenya' was initiated. This project studied aspects such as health parameters, reproduction and growth in the imported Friesians. Under the aegis of the project we studied the changes in cattle hair coat characteristics. This topic was chosen for 3 main reasons:
    - The characteristics and the cyclic changes of the hair coat are important in the ecology of cattle.
    - Various authors have drawn attention to the importance of hair coat type as an indicator of the ability of beef cattle to adapt to tropical climates.
    - There were no data on adaptation problems, with regard to hair coats, of dairy cattle.

    To complement the Kenyan data, I studied hair coat characteristics in Friesian heifers in the Netherlands. By thoroughly reviewing existing literature on hair follicles, sweat glands and hair coat characteristics in cattle, I obtained data that could be compared with the data I collected in Kenya and the Netherlands.

    The literature review (Chapter 2.) comprises a résumé of the anatomy and physiology of the hair follicle and sweat gland (section 2.1.4.); a summary of hair follicle and sweat gland characteristics (section 2.2.12.), and hair coat characteristics of cattle (section 2.3.13.); a summary of coat shedding, the effects of photoperiod, temperature and nutrition (section 2.4.4.); and the major conclusions on how hair follicle, sweat gland and hair coat characteristics relate to heat exchange, performance and adaptation (section 2.5.5.).

    Chapter 3 describes the experiments. The methods of measuring hair coat characteristics are given in paragraph 3.1. The hair samples were measured for medullation, hair diameter, hair length, melanin content, hair density and percentage of anagen hair roots. Our methods were generally the same as those reported in the literature, except for those we used to measure medullation and hair diameter.

    The results of the research on hair coat characteristics of Friesian heifers in the Netherlands are described in 3.2. In this investigation 30 heifers were sampled at regular intervals. Supplementary observations on shedding of the coat were made on 6 heifers. We found that:

    - In the same animal white hair samples were more medullated than black hair samples.

    - The changes in various hair coat characteristics did not run parallel in all body regions. In summer the coats were uniform over the body. In autumn and winter, however, various hair coat characteristics varied significantly between body regions.

    - All the characteristics considered changed with time. Large seasonal changes were found in percentage of medullated hairs, hair length and melanin content. The seasonal cycle in percentage of medullated hairs - from 50% in winter to 90% in summer -, which represents the seasonal variation in coat composition, was closely related to change in daylength.

    - Large changes in coat composition occurred in spring and in autumn. In the heifers used in the shedding experiment in autumn about 50% of the hairs were shed and the increase in hair length resulted from the growth of the 'summer' hairs.

    - The melanin content was found to be related to body weight gain.

    The hair coat characteristics of Friesian heifers after introduction into Kenya are described in paragraph 3.3. In a preliminary study we made measurements on 25 heifers brought to Kitale in October 1972. The main study was made on 27 heifers brought to Kitale in October 1973. The most important results were:

    - The percentage of medullated hairs remained at the same low level (40-50%) during the first 12 months; only after this period it increased gradually.

    A few months after arrival in Kenya the percentage of fragmentary medullated hairs rose rapidly.

    - It was striking that most animals grew very dense coats in the first six months in Kenya.

    - Both hair diameter and hair length decreased in the first 6 months in Kenya.

    - Only in those periods when the heifers experienced a rather low plane of nutrition did some hair coat characteristics correlate with body weight gain. Chapter 4 discusses some results from the experimental heifers in the Netherlands and from the heifers examined in Kenya, and presents our conclusions.

    The main outcomes were:

    - Contrary to the practice, in comparative studies black and white hairs should be studied separately. Moreover the body region chosen for sampling may significantly affect the results.

    - The experimental heifers in the Netherlands adapted to the summer conditions by developing a short, medullated, and less dense hair coat. The seasonal rhythm in coat composition is probably due to changes in photoperiod acting through the endocrine system.

    - Our results on coat shedding do not agree with those from Australia mentioned in the literature. The sequence of events in temperate zones is probably:

    a. in spring most of the hairs are replaced: the non-medullated hairs disappear almost entirely from the coat and almost all the new hairs are medullated;

    b. in autumn about 50% of the hairs are replaced: non-medullated hairs appear in the coat again, the hair density increases, and the 'summer' hairs increase markedly in length;

    c. some replacement occurs continuously throughout the year.

    - In Kenya the equatorial photoperiod probably upsets this cycle in the imported heifers. The low level of medullated hairs during the first 12 months, the marked increase in fragmentary medullated hairs, and the high hair densities in the first 6 months (mainly due to the fact that the non-medullated hairs were shed only very gradually) show that these animals had difficulties in acclimatizing. It took about 18 months before the coat composition of the heifers transferred to Kenya was about the same as that of the heifers in the Netherlands in summer. These results endorse YEATES'S (1958) view that the equatorial light environment must be regarded as an extra setback to the successful adaptation of European cattle to hot equatorial regions.

    - Contrary to the assumptions in the literature that both hair follicle and hair density decrease as the animal grows and that hair density is not subject to seasonal changes, our findings suggest that a number of follicles producing non- medullated hairs remain empty in the summer months and that the number of empty follicles per unit area is inversely proportional to the number of non- medullated hairs per unit area. This would partly explain the surprizing high hair densities in the first 6 months in Kenya, because in the heifers in Kenya dense hair coats tended to be composed of more non-medullated hairs. We have indications that in animals with extremely high hair densities a number of follicles contain two hairs. So hair follicle population figures are not equivalent to hair population figures.

    - Ambient temperature is related to hair length. The influence of temperature may be mediated by the thyroid.

    - Plane of nutrition is probably (like in sheep and men) directly related to hair diameter.

    - There was no evidence for a strong link between body weight gain and hair coat characteristics. In the Netherlands body weight gain was related to melanin content only; the significance of this relationship is not fully clear. The results in Kenya confirm the assumption of various workers that a medullated coat indicates capacity to react favourably under stressful conditions.

    - In the mild climatic conditions of Kitale the hair coat is probably not very important in relation to the thermal balance of the animal. In hot-dry and hot-wet climates heat problems may arise (at least in the first year after exportation) in animals that are transferred from the temperate to equatorial regions . This has to be investigated further.

    - Further research is also necessary to reveal the role of various hair coat characteristics on heat transfer. And it will be interesting to investigate the physiological mechanisms underlying the relationships between coat type and thrift in a tropical environment. This should be determined with animals kept under controlled conditions.

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