Staff Publications

Staff Publications

  • external user (warningwarning)
  • Log in as
  • language uk
  • About

    '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.

    We have a manual that explains all the features 

Records 1 - 20 / 22

  • help
  • print

    Print search results

  • export

    Export search results

  • alert
    We will mail you new results for this query: q=Kahn
Check title to add to marked list
Nature and mental health: An ecosystem service perspective
Bratman, Gregory N. ; Anderson, Christopher B. ; Berman, Marc G. ; Cochran, Bobby ; Vries, Sjerp De; Flanders, Jon ; Folke, Carl ; Frumkin, Howard ; Gross, James J. ; Hartig, Terry ; Kahn, Peter H. ; Kuo, Ming ; Lawler, Joshua J. ; Levin, Phillip S. ; Lindahl, Therese ; Meyer-lindenberg, Andreas ; Mitchell, Richard ; Ouyang, Zhiyun ; Roe, Jenny ; Scarlett, Lynn ; Smith, Jeffrey R. ; Bosch, Matilda Van Den; Wheeler, Benedict W. ; White, Mathew P. ; Zheng, Hua ; Daily, Gretchen C. - \ 2019
Science Advances 5 (2019)7. - ISSN 2375-2548 - 15 p.
A growing body of empirical evidence is revealing the value of nature experience for mental health. With rapid urbanization and declines in human contact with nature globally, crucial decisions must be made about how to preserve and enhance opportunities for nature experience. Here, we first provide points of consensus across the natural, social, and health sciences on the impacts of nature experience on cognitive functioning, emotional well-being, and other dimensions of mental health. We then show how ecosystem service assessments can be expanded to include mental health, and provide a heuristic, conceptual model for doing so.
Acute effects of ∆9-tetrahydrocannabinol (THC) on resting state brain function and their modulation by COMT genotype
Bossong, Matthijs G. ; Hell, Hendrika H. van; Schubart, Chris D. ; Saane, Wesley van; Iseger, Tabitha A. ; Jager, Gerry ; Osch, Matthias J.P. van; Jansma, J.M. ; Kahn, René S. ; Boks, Marco P. ; Ramsey, Nick F. - \ 2019
European Neuropsychopharmacology 29 (2019)6. - ISSN 0924-977X - p. 766 - 776.
Arterial spin labelling - Cannabis - Catechol-methyl-transferase (COMT) - Delta9-tetrahydrocannabinol (THC) - Resting state connectivity - Salience

Cannabis produces a broad range of acute, dose-dependent psychotropic effects. Only a limited number of neuroimaging studies have mapped these effects by examining the impact of cannabis on resting state brain neurophysiology. Moreover, how genetic variation influences the acute effects of cannabis on resting state brain function is unknown. Here we investigated the acute effects of ∆9-tetrahydrocannabinol (THC), the main psychoactive constituent of cannabis, on resting state brain neurophysiology, and their modulation by catechol-methyl-transferase (COMT) Val158Met genotype. Thirty-nine healthy volunteers participated in a pharmacological MRI study, where we applied Arterial Spin Labelling (ASL) to measure perfusion and functional MRI to assess resting state connectivity. THC increased perfusion in bilateral insula, medial superior frontal cortex, and left middle orbital frontal gyrus. This latter brain area showed significantly decreased connectivity with the precuneus after THC administration. THC effects on perfusion in the left insula were significantly related to subjective changes in perception and relaxation. These findings indicate that THC enhances metabolism and thus neural activity in the salience network. Furthermore, results suggest that recruitment of brain areas within this network is involved in the acute effects of THC. Resting state perfusion was modulated by COMT genotype, indicated by a significant interaction effect between drug and genotype on perfusion in the executive network, with increased perfusion after THC in Val/Met heterozygotes only. This finding suggests that prefrontal dopamine levels are involved in the susceptibility to acute effects of cannabis.

SerpinA3N is a novel hypothalamic gene upregulated by a high-fat diet and leptin in mice
Sergi, Domenico ; Campbell, Fiona M. ; Grant, Christine ; Morris, Amanda C. ; Bachmair, Eva Maria ; Koch, Christiane ; McLean, Fiona H. ; Muller, Aifric ; Hoggard, Nigel ; Roos, Baukje de; Porteiro, Begona ; Boekschoten, Mark V. ; McGillicuddy, Fiona C. ; Kahn, Darcy ; Nicol, Phyllis ; Benzler, Jonas ; Mayer, Claus Dieter ; Drew, Janice E. ; Roche, Helen M. ; Muller, Michael ; Nogueiras, Ruben ; Dieguez, Carlos ; Tups, Alexander ; Williams, Lynda M. - \ 2018
Genes & Nutrition 13 (2018). - ISSN 1555-8932
High-fat diet - Hypothalamus - Leptin - SerpinA3N

Background: Energy homeostasis is regulated by the hypothalamus but fails when animals are fed a high-fat diet (HFD), and leptin insensitivity and obesity develops. To elucidate the possible mechanisms underlying these effects, a microarray-based transcriptomics approach was used to identify novel genes regulated by HFD and leptin in the mouse hypothalamus. Results: Mouse global array data identified serpinA3N as a novel gene highly upregulated by both a HFD and leptin challenge. In situ hybridisation showed serpinA3N expression upregulation by HFD and leptin in all major hypothalamic nuclei in agreement with transcriptomic gene expression data. Immunohistochemistry and studies in the hypothalamic clonal neuronal cell line, mHypoE-N42 (N42), confirmed that alpha 1-antichymotrypsin (α1AC), the protein encoded by serpinA3, is localised to neurons and revealed that it is secreted into the media. SerpinA3N expression in N42 neurons is upregulated by palmitic acid and by leptin, together with IL-6 and TNFα, and all three genes are downregulated by the anti-inflammatory monounsaturated fat, oleic acid. Additionally, palmitate upregulation of serpinA3 in N42 neurons is blocked by the NFκB inhibitor, BAY11, and the upregulation of serpinA3N expression in the hypothalamus by HFD is blunted in IL-1 receptor 1 knockout (IL-1R1 -/- ) mice. Conclusions: These data demonstrate that serpinA3 expression is implicated in nutritionally mediated hypothalamic inflammation.

Transcriptome analysis in whole blood reveals increased microbial diversity in schizophrenia
Olde Loohuis, Loes M. ; Mangul, Serghei ; Ori, Anil P.S. ; Jospin, Guillaume ; Koslicki, David ; Yang, Harry Taegyun ; Wu, Timothy ; Boks, Marco P. ; Lomen-Hoerth, Catherine ; Wiedau-Pazos, Martina ; Cantor, Rita M. ; Vos, Willem M. De; Kahn, René S. ; Eskin, Eleazar ; Ophoff, Roel A. - \ 2018
Translational Psychiatry 8 (2018). - ISSN 2158-3188
The role of the human microbiome in health and disease is increasingly appreciated. We studied the composition of microbial communities present in blood across 192 individuals, including healthy controls and patients with three disorders affecting the brain: schizophrenia, amyotrophic lateral sclerosis, and bipolar disorder. By using high-quality unmapped RNA sequencing reads as candidate microbial reads, we performed profiling of microbial transcripts detected in whole blood. We were able to detect a wide range of bacterial and archaeal phyla in blood. Interestingly, we observed an increased microbial diversity in schizophrenia patients compared to the three other groups. We replicated this finding in an independent schizophrenia case-control cohort. This increased diversity is inversely correlated with estimated cell abundance of a subpopulation of CD8+ memory T cells in healthy controls, supporting a link between microbial products found in blood, immunity and schizophrenia.
The endocannabinoid system and emotional processing: A pharmacological fMRI study with Delta 9-tetrahydrocannabinol
Bossong, M.G. ; Hell, H.H. van; Jager, G. ; Kahn, R.S. ; Ramsey, N.F. ; Jansma, J.M. - \ 2013
European Neuropsychopharmacology 23 (2013)12. - ISSN 0924-977X - p. 1687 - 1697.
cb1 cannabinoid receptors - happy facial expressions - healthy-volunteers - antagonist rimonabant - major depression - memory function - functional mri - amygdala - brain - involvement
Various psychiatric disorders such as major depression are associated with abnormalities in emotional processing. Evidence indicating involvement of the endocannabinoid system in emotional processing, and thus potentially in related abnormalities, is increasing. In the present study, we examined the role of the endocannabinoid system in processing of stimuli with a positive and negative emotional content in healthy volunteers. A pharmacological functional magnetic resonance imaging (fMRI) study was conducted with a placebo-controlled, cross-over design, investigating effects of the endocannabinoid agonist Delta 9-tetrahydrocannabinol (THC) on brain function related to emotional processing in 11 healthy subjects. Performance and brain activity during matching of stimuli with a negative ('fearful faces') or a positive content ('happy faces') were assessed after placebo and THC administration. After THC administration, performance accuracy was decreased for stimuli with a negative but not for stimuli with a positive emotional content. Our task activated a network of brain regions including amygdala, orbital frontal gyrus, hippocampus, parietal gyrus, prefrontal cortex, and regions in the occipital cortex. THC interacted with emotional content, as activity in this network was reduced for negative content, while activity for positive content was increased. These results indicate that THC administration reduces the negative bias in emotional processing. This adds human evidence to support the hypothesis that the endocannabinoid system is involved in modulation of emotional processing. Our findings also suggest a possible role for the endocannabinoid system in abnormal emotional processing, and may thus be relevant for psychiatric disorders such as major depression. (C) 2013 Elsevier B.V. and ECNP. All rights reserved.
Effect of Doping Density on the Charge Rearrangement and Interface Dipole at the Molecule-Silicon Interface
Yaffe, O. ; Pujari, S.P. ; Sinai, O. ; Vilan, A. ; Zuilhof, H. ; Kahn, A. ; Kronik, L. ; Cohen, H. ; Cahen, D. - \ 2013
The Journal of Physical Chemistry Part C: Nanomaterials and Interfaces 117 (2013)43. - ISSN 1932-7447 - p. 22422 - 22427.
self-assembled monolayers - flat h-si(111) surfaces - energy-level alignment - organic monolayers - si(111) surfaces - electronic-properties - 40-percent nh4f - work-function - devices - oxide
The interface level alignment of alkyl and alkenyl monolayers, covalently bound to oxide-free Si substrates of various doping levels, is studied using X-ray photoelectron spectroscopy. Using shifts in the C 1s and Si 2p photoelectron peaks as a sensitive probe, we find that charge distribution around the covalent Si–C bond dipole changes according to the initial position of the Fermi level within the Si substrate. This shows that the interface dipole is not fixed but rather changes with the doping level. These results set limits to the applicability of simple models to describe level alignment at interfaces and show that the interface bond and dipole may change according to the electrostatic potential at the interface.
Effect of Different Levels of Organic Acids Supplementation on Feed Intake, Milk Yield and Milk composition of Dairy Cows during Thermal Stress
Kahn, S. ; Ali, A. ; Mobashar, M. ; Inam, M. ; Ahmed, I. ; Khan, N.A. ; Ali, Mubarak ; Khan, H. - \ 2013
Greener Journal of Agricultural Sciences 3 (2013). - ISSN 2276-7770 - p. 762 - 768.
In many developing countries in the tropics, thermal stress results in lower feed intake, changes in energy metabolism, alterations in endocrine profiles of dairy cows which lead to animal health problems and production losses. Supplementation of organic acids can reduce the toxic metabolites and endocrine changes in the cow’s body during thermal stress. The present study was conducted at University Dairy Farm, The University of Agriculture, Peshawar to determine the effect of supplementing different levels of organic acids solution in drinking water on the milk yield, milk composition, milk somatic cell count (SCC), blood haemoglobin (Hb) and packed cell volume (PCV) of dairy cows during thermal stress. The solution of organic acids was prepared by dissolving 80g citric acid, 90g phosphoric acid, 50g lactic acid and 10g copper sulphate in one litre of distilled water. Twelve Holstein Friesian dairy cows (mid-lactation, 3 to 4 years old) having average body weight of 400kg were blocked into four groups on the basis of parity and milk yield. The cows were offered water without (group A) or with organic acids solution at the rate of 0.5, 1 or 1.5ml per litre of drinking water. The experiment was continued for 30 days along with two weeks adaptation period during the summer months of July and August, 2012. The addition of organic acids to the drinking water increased (P
Default Mode Network in the Effects of ¿9-Tetrahydrocannabinol (THC) on Human Executive Function
Bossong, M.G. ; Jansma, J.M. ; Hell, H.H. van; Jager, G. ; Kahn, R.S. ; Ramsey, N.F. - \ 2013
PLoS ONE 8 (2013)7. - ISSN 1932-6203 - 10 p.
deficit hyperactivity disorder - working-memory - endocannabinoid system - healthy-volunteers - prefrontal cortex - synaptic plasticity - error awareness - brain-function - neural basis - fmri
Evidence is increasing for involvement of the endocannabinoid system in cognitive functions including attention and executive function, as well as in psychiatric disorders characterized by cognitive deficits, such as schizophrenia. Executive function appears to be associated with both modulation of active networks and inhibition of activity in the default mode network. In the present study, we examined the role of the endocannabinoid system in executive function, focusing on both the associated brain network and the default mode network. A pharmacological functional magnetic resonance imaging (fMRI) study was conducted with a placebo-controlled, cross-over design, investigating effects of the endocannabinoid agonist ¿9-tetrahydrocannabinol (THC) on executive function in 20 healthy volunteers, using a continuous performance task with identical pairs. Task performance was impaired after THC administration, reflected in both an increase in false alarms and a reduction in detected targets. This was associated with reduced deactivation in a set of brain regions linked to the default mode network, including posterior cingulate cortex and angular gyrus. Less deactivation was significantly correlated with lower performance after THC. Regions that were activated by the continuous performance task, notably bilateral prefrontal and parietal cortex, did not show effects of THC. These findings suggest an important role for the endocannabinoid system in both default mode modulation and executive function. This may be relevant for psychiatric disorders associated with executive function deficits, such as schizophrenia and ADHD
THC reduces the anticipatory nucleus accumbens response to reward in subjects with a nicotine addiction
Jansma, J.M. ; Hell, H.H. van; Vanderschuren, L.J.M.J. ; Bossong, M.G. ; Jager, G. ; Kahn, R.S. ; Ramsey, N.F. - \ 2013
Translational Psychiatry 3 (2013). - ISSN 2158-3188 - 10 p.
endogenous cannabinoid anandamide - increasing monetary reward - endocannabinoid system - drug-addiction - cb1 receptors - brain - dependence - rats - inhibition - humans
Recent evidence has implicated the endocannabinoid (eCB) system in nicotine addiction. The eCB system also has an important role in reward mechanisms, and nicotine addiction has been associated with aberrant reward processing. Motivated by this evidence, we tested the hypothesis that eCB modulation of reward processing is altered in subjects with a nicotine addiction (NAD). For this purpose, we compared reward-related activity in NAD with healthy controls (HC) in a pharmacological magnetic resonance imaging (MRI) study using ¿9-tetrahydrocannabinol (THC) administration to challenge the eCB system. Eleven HC and 10 NAD participated in a 3-T functional MRI (fMRI) study with a double-blind, cross-over, placebo-controlled design, using a Monetary Incentive Delay (MID) paradigm with three reward levels. Reward activity in the nucleus accumbens (NAcc) and caudate putamen during anticipation and feedback of reward was compared after THC and placebo. fMRI results indicated a significant reduction of reward anticipation activity in the NAcc in NAD after THC administration, which was not present in HC. This is indicated by a significant group by drug by reward interaction. Our data show that THC significantly reduces the NAcc response to monetary reward anticipation in NAD. These results suggest that nicotine addiction is associated with altered eCB modulation of reward processing in the NAcc. This study adds important human data to existing evidence implicating the eCB system in nicotine addiction.
Charge transport across metal/molecular (alkyl) monolayer-Si junctions is dominated by the LUMO level
Yaffe, O. ; Qi, Y. ; Scheres, L.M.W. ; Puniredd, S.R. ; Segev, L. ; Ely, T. ; Haick, H. ; Zuilhof, H. ; Vilan, A. ; Kronik, L. ; Kahn, A. ; Cahen, D. - \ 2012
Physical Review. B : Condensed Matter and Materials Physics 85 (2012)4. - ISSN 1098-0121
self-assembled monolayers - electronic transport - molecular electronics - organic-molecules - chain monolayers - spectroscopy - polyethylene - conductance - films - photoemission
We compare the charge transport characteristics of heavy-doped p(++)- and n(++)-Si-alkyl chain/Hg junctions. Based on negative differential resistance in an analogous semiconductor-inorganic insulator/metal junction we suggest that for both p(++)- and n(++)-type junctions, the energy difference between the Fermi level and lowest unoccupied molecular orbital (LUMO), i.e., electron tunneling, controls charge transport. This conclusion is supported by results from photoelectron spectroscopy (ultraviolet photoemission spectroscopy, inverse photoelectron spectroscopy, and x-ray photoemission spectroscopy) for the molecule-Si band alignment at equilibrium, which clearly indicate that the energy difference between the Fermi level and the LUMO is much smaller than that between the Fermi level and the highest occupied molecular orbital (HOMO). Furthermore, the experimentally determined Fermi level - LUMO energy difference, agrees with the non-resonant tunneling barrier height, deduced from the exponential length attenuation of the current.
Effects of ¿9-Tetrahydrocannabinol Administration on human encoding and recall memory function: a pharmacological fMRI study
Bossong, M.G. ; Jager, G. ; Hell, H.H. van; Zuurman, L. ; Jansma, J.M. ; Mehta, M.A. ; Gerven, J. van; Kahn, R.S. ; Ramsey, N.F. - \ 2012
Journal of Cognitive Neuroscience 24 (2012)3. - ISSN 0898-929X - p. 588 - 599.
long-term-memory - impairs spatial memory - medial temporal-lobe - recognition memory - episodic retrieval - prefrontal cortex - smoked marijuana - semantic memory - oral delta(9)-tetrahydrocannabinol - healthy-volunteers
Deficits in memory function are an incapacitating aspect of various psychiatric and neurological disorders. Animal studies have recently provided strong evidence for involvement of the endocannabinoid (eCB) system in memory function. Neuropsychological studies in humans have shown less convincing evidence but suggest that administration of cannabinoid substances affects encoding rather than recall of information. In this study, we examined the effects of perturbation of the eCB system on memory function during both encoding and recall. We performed a pharmacological MRI study with a placebo-controlled, crossover design, investigating the effects of ¿9-tetrahydrocannabinol (THC) inhalation on associative memory-related brain function in 13 healthy volunteers. Performance and brain activation during associative memory were assessed using a pictorial memory task, consisting of separate encoding and recall conditions. Administration of THC caused reductions in activity during encoding in the right insula, the right inferior frontal gyrus, and the left middle occipital gyrus and a network-wide increase in activity during recall, which was most prominent in bilateral cuneus and precuneus. THC administration did not affect task performance, but while during placebo recall activity significantly explained variance in performance, this effect disappeared after THC. These findings suggest eCB involvement in encoding of pictorial information. Increased precuneus activity could reflect impaired recall function, but the absence of THC effects on task performance suggests a compensatory mechanism. These results further emphasize the eCB system as a potential novel target for treatment of memory disorders and a promising target for development of new therapies to reduce memory deficits in humans
Effects of ¿9-Tetrahydrocannabinol on human working memory function
Bossong, M.G. ; Jansma, J.M. ; Hell, H.H. van; Jager, G. ; Oudman, E. ; Saliasi, E. ; Kahn, R.S. ; Ramsey, N.F. - \ 2012
Biological Psychiatry 71 (2012)8. - ISSN 0006-3223 - p. 693 - 699.
dorsolateral prefrontal cortex - catechol-o-methyltransferase - endogenous cannabinoids - genetic-variation - brain-function - schizophrenia - dysfunction - fmri - mri - cognition
Background Evidence indicates involvement of the endocannabinoid (eCB) system in both the pathophysiology of schizophrenia and working memory (WM) function. Additionally, schizophrenia patients exhibit relatively strong WM deficits. These findings suggest the possibility that the eCB system is also involved in WM deficits in schizophrenia. In the present study, we examined if perturbation of the eCB system can induce abnormal WM activity in healthy subjects. Methods A pharmacological functional magnetic resonance imaging study was conducted with a placebo-controlled, cross-over design, investigating effects of the eCB agonist ¿9-tetrahydrocannabinol on WM function in 17 healthy volunteers, by means of a parametric Sternberg item-recognition paradigm with five difficulty levels. Results Performance accuracy was significantly reduced after ¿9-tetrahydrocannabinol. In the placebo condition, brain activity increased linearly with rising WM load. ¿9-Tetrahydrocannabinol administration enhanced activity for low WM loads and reduced the linear relationship between WM load and activity in the WM system as a whole and in left dorsolateral prefrontal cortex, inferior temporal gyrus, inferior parietal gyrus, and cerebellum in particular. Conclusions ¿9-Tetrahydrocannabinol enhanced WM activity network-wide for low loads, while reducing the load-dependent response for increasing WM loads. These results indicate that a challenged eCB system can induce both abnormal WM activity and WM performance deficits and provide an argument for the possibility of eCB involvement in WM deficits in schizophrenia
Involvement of the endocannabinoid system in reward processing in the human brain
Hell, H.H. van; Jager, G. ; Bossong, M.G. ; Brouwer, A. ; Jansma, J.M. ; Zuurman, L. ; Gerven, J. van; Kahn, R.S. ; Ramsey, N.F. - \ 2012
Psychopharmacology 219 (2012)4. - ISSN 0033-3158 - p. 981 - 990.
acute oral delta(9)-tetrahydrocannabinol - cannabinoid cb1 receptors - healthy-volunteers - clinical-research - dopamine release - decision-making - human striatum - neural-basis - thc - delta-9-tetrahydrocannabinol
Rationale Disturbed reward processing in humans has been associated with a number of disorders, such as depression, addiction, and attention-deficit hyperactivity disorder. The endocannabinoid (eCB) system has been implicated in reward processing in animals, but in humans, the relation between eCB functioning and reward is less clear. Objectives The current study uses functional magnetic resonance imaging (fMRI) to investigate the role of the eCB system in reward processing in humans by examining the effect of the eCB agonist ¿9-tetrahydrocannabinol (THC) on reward-related brain activity. Methods Eleven healthy males participated in a randomized placebo-controlled pharmacological fMRI study with administration of THC to challenge the eCB system. We compared anticipatory and feedback-related brain activity after placebo and THC, using a monetary incentive delay task. In this task, subjects are notified before each trial whether a correct response is rewarded (“reward trial”) or not (“neutral trial”). Results Subjects showed faster reaction times during reward trials compared to neutral trials, and this effect was not altered by THC. THC induced a widespread attenuation of the brain response to feedback in reward trials but not in neutral trials. Anticipatory brain activity was not affected. Conclusions These results suggest a role for the eCB system in the appreciation of rewards. The involvement of the eCB system in feedback processing may be relevant for disorders in which appreciation of natural rewards may be affected such as addiction
Somatostatin in the Periventricular Nucleus of the Female Rat: Age Specific Effects of Estrogen and Onset of Reproductive Aging
Beek, E.M. van der; Vugt, H.H. van; Franke, A.N. ; Heijning, B.J.M. van de - \ 2011
In: Sex Steroids / Kahn, S.M., Rijeka : InTech - ISBN 9789533078571
Evidence for involvement of the insula in the psychotropic effects of THC in humans: a double-blind, randomized pharmacological MRI study
Hell, H.H. van; Bossong, M.G. ; Jager, G. ; Kristo, G. ; Osch, M.J.P. ; Zelaya, F. ; Kahn, R.S. ; Ramsey, N.F. - \ 2011
International Journal of Neuropsychopharmacology 14 (2011)10. - ISSN 1461-1457 - p. 1377 - 1388.
cerebral-blood-flow - low-frequency fluctuation - central-nervous-system - resting-state fmri - neural-basis - anterior insula - healthy-volunteers - marijuana smoking - functional mri - cannabis use
The main reason for recreational use of cannabis is the ‘high’, the primary psychotropic effect of ¿9-tetrahydrocannabinol (THC). This psychoactive compound of cannabis induces a range of subjective, physical and mental reactions. The effect on heart rate is pronounced and complicates bloodflow-based neuroimaging of psychotropic effects of THC. In this study we investigated the effects of THC on baseline brain perfusion and activity in association with the induction of ‘feeling high’. Twenty-three subjects participated in a pharmacological MRI study, where we applied arterial spin labelling (ASL) to measure perfusion, and resting-state functional MRI to assess blood oxygen level-dependent signal fluctuation as a measure of baseline brain activity. Feeling high was assessed with a visual analogue scale and was compared to the imaging measures. THC increased perfusion in the anterior cingulate cortex, superior frontal cortex, and insula, and reduced perfusion in the post-central and occipital gyrus. Baseline brain activity was altered, indicated by increased amplitude of fluctuations in resting-state functional MRI signal after THC administration in the insula, substantia nigra and cerebellum. Perfusion changes in frontal cortex were negatively correlated with ratings of feeling high, suggesting an interaction between cognitive control and subjective effects of THC. In conclusion, an acute THC challenge altered baseline brain perfusion and activity, especially in frontal brain areas involved in cognitive and emotional processes, and the insula, associated with interoceptive awareness. These changes may represent the THC-induced neurophysiological correlates of feeling high. The alterations in baseline brain perfusion and activity also have relevance for studies on task-related effects of THC on brain function.
Hg/Molecular Monolayer-Si Junctions: Electrical Interplay between Monolayer Properties and Semiconductor Doping Density
Yaffe, O. ; Scheres, L.M.W. ; Segev, O. ; Biller, A. ; Ron, I. ; Salomon, E. ; Giesbers, M. ; Kahn, A. ; Kronik, L. ; Zuilhof, H. ; Vilan, A. ; Cahen, D. - \ 2010
The Journal of Physical Chemistry Part C: Nanomaterials and Interfaces 114 (2010)22. - ISSN 1932-7447 - p. 10270 - 10279.
crystalline silicon surfaces - voltaic energy-conversion - linked organic monolayers - self-assembled monolayers - flat h-si(111) surfaces - alkyl chain monolayers - metal work function - mis tunnel-diodes - current transport - si(111) surfaces
Metal-organic molecule-semiconductor junctions are controlled not only by the molecular properties, as in metal-organic molecule-metal junctions, but also by effects of the molecular dipole, the dipolar molecule-semiconductor link, and molecule-semiconductor charge transfer, and by the effects of all these on the semiconductor depletion layer (i.e., on the internal semiconductor barrier to charge transport). Here, we report on and compare the electrical properties (current-voltage, capacitance-voltage, and work function) of large area Hg/organic monolayer-Si junctions with alkyl and alkenyl monolayers on moderately and highly doped n-Si, and combine the experimental data with simulations of charge transport and electronic structure calculations. We show that, for moderately doped Si, the internal semiconductor barrier completely controls transport and the attached molecules influence the transport of such junctions only in that they drive the Si into inversion. The resulting minority carrier-controlled junction is not sensitive to molecular changes in the organic monolayer at reverse and low forward bias and is controlled by series resistance at higher forward bias. However, in the case of highly doped Si, the internal barrier is smaller, and as a result, the charge transport properties of the junction are affected by changing from an alkyl to an alkenyl monolayer. We propose that the double bond near the surface primarily increases the coupling between the organic monolayer and the Si, which increases the current density at a given bias by increasing the contact conductance.
Genes for seed quality: a physiological genetical genomics approach
Ligterink, W. ; Joosen, R.V.L. ; Kazmi, R.H. ; Kahn, N. ; Willems, L. ; Hilhorst, H.W.M. - \ 2009
Unraveling the complex trait of seed quality in tomato
Ligterink, W. ; Kazmi, R.H. ; Kahn, N. ; Willems, L. ; Hilhorst, H.W.M. - \ 2009
In: Proceedings of the 13th Quantitative Trait Locus and Marker Assisted Selection Workshop, Wageningen, The Netherlands, 20-21 April 2009. - - p. 9 - 9.
Summary for Policymakers
Barker, T. ; Bashmakov, I. ; Bernstein, L. ; Bogner, J. ; Bosch, P. ; Dave, R. ; Davidson, O. ; Fisher, B. ; Grubb, M. ; Gupta, S. ; Halsnaes, K. ; Heij, B.J. ; Kahn Ribeiro, S. ; Kobayashi, S. ; Levine, M. ; Martino, D. ; Masera Cerutti, O. ; Metz, B. ; Meyer, L. ; Nabuurs, G.J. ; Najam, A. ; Nakicenovic, N. ; Rogner, H.H. ; Roy, J. ; Sathaye, J. ; Schock, R. ; Shukla, P. ; Sims, R. ; Smith, P. ; Swart, R. ; Tirpak, D. ; Urge-Vorsatz, D. ; Dadi, Z. - \ 2007
In: Climate Change 2007: Mitigation. Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change / Metz, B., Davidson, O.R., Bosch, P.R., Dave, R., Meyer, L.A., Cambridge (UK) and New York (USA) : Cambridge University Press (Climate Change 2007 ) - ISBN 9780521880114 - p. 1 - 24.
Dual Earners, Urban Labor Markets and Housing Demand
Rouwendal, J. ; Straaten, J.W. van der - \ 2003
Amsterdam : Tinbergen Institute (Tinbergen Institute Discussion Paper 2003-084/3) - 28 p.
This paper replicates Costa and Kahn's analysis of locational choices of couples of highly educated persons for the Netherlands. We find increasing concentration of such power couples in the urbanized western part of the country. This trend occurs in spite of the absence of an urban wage premium for university-educated workers and the concentration of congestion there. We find that power couples locate more often in medium sized and larger cities than otherwise comparable households and that they are relatively often owner-occupiers and live in more expensive housing. Their commutes are relatively short when it is taken into account that it is more difficult for these households to find suitable combinations of employment and residence locations than it is for single earner households. A probable explanation for these findings is that power couples use their relatively large purchasing power to outbid other households from locations that are especially attractive t! o them, as is predicted by household location theory.
Check title to add to marked list
<< previous | next >>

Show 20 50 100 records per page

Please log in to use this service. Login as Wageningen University & Research user or guest user in upper right hand corner of this page.