Automatic phase control in solar power satellite systems

Various approaches to the problem of generating, maintaining and distributing a coherent, reference phase signal over a large area are suggested, mathematically modeled and analyzed with respect to their ability to minimize: phase build-up, beam diffusion and beam steering phase jitter, cable length, and maximize power transfer efficiency. In addition, phase control configurations are suggested which alleviate the need for layout symmetry

Analytical simulation of SPS system performance, volume 3, phase 3

The simulation model for the Solar Power Satellite spaceantenna and the associated system imperfections are described. Overall power transfer efficiency, the key performance issue, is discussed as a function of the system imperfections. Other system performance measures discussed include average power pattern, mean beam gain reduction, and pointing error

Solar Power Satellite antenna phase control system hardware simulation, phase 4: Volume 1: Executive summary

The phase control system is described. Potential sources of phase error are identified and the performance leading to selection of the allowable phase error for each source is summarized. The pilot transmitter, the effects of ionospheric, the master slave returnable timing system (MSRTS), the SPS receiver, and the high power amplifier for dc to microwave conversion are considered separately. Design parameters of the pilot transmitter and spacetenna transponder are presented

Solar Power Satellite antenna phase control system hardware simulation, phase 4. Volume 2: Analytical simulation of SPS system performance

The pilot signal parameter optimization and power transponder analyses are presented. The SPS antenna phase control system is modeled and the hardware simulation study described. Ionospheric and system phase error effects and the effects of high power amplifier phase and amplitude jitters are considered. Parameter optimization of the spread spectrum receiver, consisting of the carrier tracking loop and the code tracking loop, is described

Blockade of alpha 2-adrenergic receptors in prelimbic cortex: impact on cocaine self-administration in adult spontaneously hypertensive rats following adolescent atomoxetine treatment

RATIONALE: Research with the spontaneously hypertensive rat (SHR) model of attention deficit/hyperactivity disorder demonstrated that chronic methylphenidate treatment during adolescence increased cocaine self-administration established during adulthood under a progressive ratio (PR) schedule. Compared to vehicle, chronic atomoxetine treatment during adolescence failed to increase cocaine self-administration under a PR schedule in adult SHR. OBJECTIVES: We determined if enhanced noradrenergic transmission at α2-adrenergic receptors within prefrontal cortex contributes to this neutral effect of adolescent atomoxetine treatment in adult SHR. METHODS: Following treatment from postnatal days 28–55 with atomoxetine (0.3 mg/kg) or vehicle, adult male SHR and control rats from Wistar-Kyoto (WKY) and Wistar (WIS) strains were trained to self-administer 0.3 mg/kg cocaine. Self-administration performance was evaluated under a PR schedule of cocaine delivery following infusion of the α2-adrenergic receptor antagonist idazoxan (0 and 10–56 μg/side) directly into prelimbic cortex. RESULTS: Adult SHR attained higher PR break points and had greater numbers of active lever responses and infusions than WKY and WIS. Idazoxan dose-dependently increased PR break points and active lever responses in SHR following adolescent atomoxetine vs. vehicle treatment. Behavioral changes were negligible after idazoxan pretreatment in SHR following adolescent vehicle or in WKY and WIS following adolescent atomoxetine or vehicle. CONCLUSIONS: α2-Adrenergic receptor blockade in prelimbic cortex of SHR masked the expected neutral effect of adolescent atomoxetine on adult cocaine self-administration behavior. Moreover, greater efficacy of acute idazoxan challenge in adult SHR after adolescent atomoxetine relative to vehicle is consistent with the idea that chronic atomoxetine may downregulate presynaptic α2A-adrenergic autoreceptors in SHR.National Institutes of Health grant DA011716. (DA011716 - National Institutes of Health)https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5693724/Published versio

SPS phase control system performance via analytical simulation

A solar power satellite transmission system which incorporates automatic beam forming, steering, and phase control is discussed. The phase control concept centers around the notation of an active retrodirective phased array as a means of pointing the beam to the appropriate spot on Earth. The transmitting antenna (spacetenna) directs the high power beam so that it focuses on the ground-based receiving antenna (rectenna). A combination of analysis and computerized simulation was conducted to determine the far field performance of the reference distribution system, and the beam forming and microwave power generating systems

Metal-Free Intermolecular Oxidative C–N Bond Formation via Tandem C–H and N–H Bond Functionalization

The development of a novel intermolecular oxidative amination reaction, a synthetic transformation that involves the simultaneous functionalization of both a N–H and C–H bond, is described. The process, which is mediated by an I(III) oxidant and contains no metal catalysts, provides a rapid and green method for synthesizing protected anilines from simple arenes and phthalimide. Mechanistic investigations indicate that the reaction proceeds via nucleophilic attack of the phthalimide on an aromatic radical cation, as opposed to the electrophilic aromatic amination that has been reported for other I(III) amination reactions. The application of this new reaction to the synthesis of a variety of substituted aniline derivatives is demonstrated

Thermal Damage Estimate Artifact Following Antecedent Biopsy: A Case Report

MR-guided laser interstitial therapy (MRgLITT) is becoming more commonly used for minimal access approaches to intracranial lesions of all etiologies. The short-term safety profile of MRgLITT is favorable compared with sweeping incisions and open craniotomies, especially for lesions located in deep, periventricular, and highly eloquent areas. The Visualase software (Medtronic Inc., Minneapolis, MN, USA) has multiple adaptations to assist with this safety margin, including the thermal damage estimate (TDE), which applies predictive mathematical modeling to a two-dimensional (2D) graphical representation. TDE has been shown to highly correlate with actual tissue destruction in a priori MRgLITT cases and to anecdotally be imprecise when MRgLITT is combined with biopsy. We present a case regarding a 17-year-old male patient with intractable focal epilepsy. He underwent stereotactic biopsy and then ablation where it was shown that TDE is ~35% larger in the coronal plane than in the actual ablation zone. Air may have caused this artifact in the biopsy cavity, which affected the proton resonance frequency (PRF) and caused TDE pigment deposition. We believe in the need for a more comprehensive understanding and investigation regarding this TDE artifact. Future prospective studies into MRgLITT should attend carefully in cases where it is combined with biopsy

Lateral Hypothalamic Area Glutamatergic Neurons and Their Projections to the Lateral Habenula Regulate Feeding and Reward

The overconsumption of calorically dense, highly palatable foods is thought to be a major contributor to the worldwide obesity epidemic; however, the precise neural circuits that directly regulate hedonic feeding remain elusive. Here, we show that lateral hypothalamic area (LHA) glutamatergic neurons, and their projections to the lateral habenula (LHb), negatively regulate the consumption of palatable food. Genetic ablation of LHA glutamatergic neurons increased daily caloric intake and produced weight gain in mice that had access to a high-fat diet, while not altering general locomotor activity. Anterior LHA glutamatergic neurons send a functional glutamatergic projection to the LHb, a brain region involved in processing aversive stimuli and negative reward prediction outcomes. Pathway-specific, optogenetic stimulation of glutamatergic LHA-LHb circuit resulted in detectable glutamate-mediated EPSCs as well as GABA-mediated IPSCs, although the net effect of neurotransmitter release was to increase the firing of most LHb neurons. In vivo optogenetic inhibition of LHA-LHb glutamatergic fibers produced a real-time place preference, whereas optogenetic stimulation of LHA-LHb glutamatergic fibers had the opposite effect. Furthermore, optogenetic inhibition of LHA-LHb glutamatergic fibers acutely increased the consumption of a palatable liquid caloric reward. Collectively, these results demonstrate that LHA glutamatergic neurons are well situated to bidirectionally regulate feeding and potentially other behavioral states via their functional circuit connectivity with the LHb and potentially other brain regions

Considerations When Using Cre-Driver Rodent Lines for Studying Ventral Tegmental Area Circuitry

The use of Cre-driver rodent lines for targeting ventral tegmental area (VTA) cell types has generated important and novel insights into how precise neurocircuits regulate physiology and behavior. While this approach generally results in enhanced cellular specificity, an important issue has recently emerged related to the selectivity and penetrance of viral targeting of VTA neurons using several Cre-driver transgenic mouse lines. Here, we highlight several considerations when utilizing these tools to study the function of genetically defined neurocircuits. While VTA dopaminergic neurons have previously been targeted and defined by the expression of single genes important for aspects of dopamine neurotransmission, many VTA and neighboring cells display dynamic gene expression phenotypes that are partially consistent with both classically described dopaminergic and non-dopaminergic neurons. Thus, in addition to varying degrees of selectivity and penetrance, distinct Cre lines likely permit targeting of partially overlapping, but not identical VTA cell populations