57 research outputs found

    Characterization of CMOS Spiral Inductors

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    In this work "full-wave" simulations of integrated inductors are presented and compared with measurements of fabricated CMOS chips. The good agreement between measurements and simulations demonstrates the accuracy of the tool, which is, hence, a cheaper alternative to experimental characterization. Furthermore, the proposed approach may give precious hints for performance improvements, by making internal device fields and currents available for the VLSI designer and providing compact, most effective, equivalent models

    Pregabalin reduces cocaine self-administration and relapse to cocaine seeking in the rat

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    Pregabalin (Lyricaâ„¢) is a structural analog of g-aminobutyric acid (GABA) and is approved by the FDA for partial epilepsy, neuropathic pain and generalized anxiety disorders. Pregabalin also reduces excitatory neurotransmitter release and post-synaptic excitability. Recently, we demonstrated that pregabalin reduced alcohol intake and prevented relapse to the alcohol seeking elicited by stress or environmental stimuli associated with alcohol availability. Here, we sought to extend these findings by examining the effect of pregabalin on cocaine self-administration (0.25 mg/infusion) and on cocaine seeking elicited by both conditioned stimuli and stress, as generated by administration of yohimbine (1.25 mg/kg). The results showed that oral administration of pregabalin (0, 10 or 30 mg/kg) reduced self-administration of cocaine over an extended period (6 hours), whereas it did not modify self-administration of food. In cocaine reinstatement studies, pregabalin (10 and 30 mg/kg) abolished the cocaine seeking elicited by both the pharmacological stressor yohimbine and the cues predictive of cocaine availability. Overall, these results demonstrate that pregabalin may have potential in the treatment of some aspects of cocaine addiction

    Stress-Induced Reinstatement of Drug Seeking: 20 Years of Progress

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    In human addicts, drug relapse and craving are often provoked by stress. Since 1995, this clinical scenario has been studied using a rat model of stress-induced reinstatement of drug seeking. Here, we first discuss the generality of stress-induced reinstatement to different drugs of abuse, different stressors, and different behavioral procedures. We also discuss neuropharmacological mechanisms, and brain areas and circuits controlling stress-induced reinstatement of drug seeking. We conclude by discussing results from translational human laboratory studies and clinical trials that were inspired by results from rat studies on stress-induced reinstatement. Our main conclusions are (1) The phenomenon of stress-induced reinstatement, first shown with an intermittent footshock stressor in rats trained to self-administer heroin, generalizes to other abused drugs, including cocaine, methamphetamine, nicotine, and alcohol, and is also observed in the conditioned place preference model in rats and mice. This phenomenon, however, is stressor specific and not all stressors induce reinstatement of drug seeking. (2) Neuropharmacological studies indicate the involvement of corticotropin-releasing factor (CRF), noradrenaline, dopamine, glutamate, kappa/dynorphin, and several other peptide and neurotransmitter systems in stress-induced reinstatement. Neuropharmacology and circuitry studies indicate the involvement of CRF and noradrenaline transmission in bed nucleus of stria terminalis and central amygdala, and dopamine, CRF, kappa/dynorphin, and glutamate transmission in other components of the mesocorticolimbic dopamine system (ventral tegmental area, medial prefrontal cortex, orbitofrontal cortex, and nucleus accumbens). (3) Translational human laboratory studies and a recent clinical trial study show the efficacy of alpha-2 adrenoceptor agonists in decreasing stress-induced drug craving and stress-induced initial heroin lapse

    Endocannabinoid Regulation of Acute and Protracted Nicotine Withdrawal: Effect of FAAH Inhibition

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    Evidence shows that the endocannabinoid system modulates the addictive properties of nicotine. In the present study, we hypothesized that spontaneous withdrawal resulting from removal of chronically implanted transdermal nicotine patches is regulated by the endocannabinoid system. A 7-day nicotine dependence procedure (5.2 mg/rat/day) elicited occurrence of reliable nicotine abstinence symptoms in Wistar rats. Somatic and affective withdrawal signs were observed at 16 and 34 hours following removal of nicotine patches, respectively. Further behavioral manifestations including decrease in locomotor activity and increased weight gain also occurred during withdrawal. Expression of spontaneous nicotine withdrawal was accompanied by fluctuation in levels of the endocannabinoid anandamide (AEA) in several brain structures including the amygdala, the hippocampus, the hypothalamus and the prefrontal cortex. Conversely, levels of 2-arachidonoyl-sn-glycerol were not significantly altered. Pharmacological inhibition of fatty acid amide hydrolase (FAAH), the enzyme responsible for the intracellular degradation of AEA, by URB597 (0.1 and 0.3 mg/kg, i.p.), reduced withdrawal-induced anxiety as assessed by the elevated plus maze test and the shock-probe defensive burying paradigm, but did not prevent the occurrence of somatic signs. Together, the results indicate that pharmacological strategies aimed at enhancing endocannabinoid signaling may offer therapeutic advantages to treat the negative affective state produced by nicotine withdrawal, which is critical for the maintenance of tobacco use

    Process evaluation of a web-based intervention aimed at empowerment of disability benefit claimants

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    <p>Abstract</p> <p>Background</p> <p>The objective of this process evaluation study was to gain insight into the reach, compliance, appreciation, usage barriers, and users' perceived effectiveness of a web-based intervention <url>http://www.wiagesprek.nl</url>. This intervention was aimed at empowerment of disability claimants, prior to the assessment of disability by an insurance physician.</p> <p>Methods</p> <p>Reach was determined by registering claimants exposed to the study's invitation brochures, and by comparing trial participant characteristics with non-participants and nationwide claimant data. Compliance was registered by analyzing weblogs, which were automatically collected during the period of the trial. This made it possible to analyze individual use of the intervention. Appreciation, usage barriers, and users' perceived effectiveness were assessed using an online questionnaire that was sent to participants from the intervention group, 6 weeks after enrolment.</p> <p>Results</p> <p>Only 9% of the target population enrolled in the internet program. Because of selective enrolment, more females, higher educated claimants, and less ethnical minorities were reached. Compliance was ambiguous: out of the 123 participants randomized into the intervention group, a significant proportion (33%) did not use the intervention at all, while, at the same time, many participants (32%) used the intervention for more than two hours (i.e. in approximately two weeks). Overall satisfaction with the intervention was good. Claimants perceived the intervention most effective in increasing knowledge, while also a fair amount of users perceived the intervention effective in gaining right expectations or being able to communicate better with their physician.</p> <p>Conclusions</p> <p>The uptake of the intervention <url>http://www.wiagesprek.nl</url> was disappointing. Specifically, the poor reach and compliance of the intervention resulted in a small proportion of the target population using the intervention as intended. Improvements in the implementation process are desirable to increase the reach and compliance and, thereby possibly, the impact of the intervention.</p> <p>Trial registration</p> <p><a href="http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=1414">NTR-1414</a></p

    Application of LE-FDTD analysis to non-linear circuits, including GaAs devices

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    We discuss the application of the Lumped-Eleinrrn., Finite-Difference TiitK-DumaJii (LE-FDTD) al­gorithm l.o the analysis of a planar active antenna. Through this approach, the full-wave si^na! propagation along the passive network is taken into account, at. the same time accounting for nun linear devices to be comprehensively considered. GaAs, as well as silicon, devices can he self-consist-enilv taken into account, and described either by a compact, analytical equations set, or by a distributed, numerical solution of the semiconductor transport equations. Both approaches arc illustrated in the paper: a OaAS Gunn diode is used to excite a slot, antenna, and is modeled at tbe distributed level; the same structure is then used as a frequency multiplier: in this case, non linearity is introduced by a Schot-tky diode, which is described hy a, compact equivalent circuit. In both cases, influence of the diode placement across the sloi is briefly discussed
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