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Transcutaneous vagus nerve stimulation (tVNS) is a promising therapeutic option for major depressive disorder (MDD) in adults. Alternative third-line treatments for MDD in adolescents are scarce. Here we aimed to assess the effects of acute tVNS on emotion recognition in adolescents with MDD.
Adolescents (14–17 years) with MDD (n = 33) and non-depressed controls (n = 30) received tVNS or sham-stimulation in a cross-sectional, case–control, within-subject cross-randomized controlled trial, while performing different tasks assessing emotion recognition. Correct responses, response times, and errors of omission and commission on three different computerized emotion recognition tasks were assessed as main outcomes. Simultaneous recordings of electrocardiography and electro dermal activity, as well as sampling of saliva for the determination of α-amylase, were used to quantify the effects on autonomic nervous system function.
tVNS had no effect on the recognition of gradually or static expressed emotions but altered response inhibition on the emotional Go/NoGo-task. Specifically, tVNS increased the likelihood of omitting a response toward sad target-stimuli in adolescents with MDD, while decreasing errors (independent of the target emotion) in controls. Effects of acute tVNS on autonomic nervous system function were found in non-depressed controls only.
Acute tVNS alters the recognition of briefly presented facial expressions of negative valence in adolescents with MDD while generally increasing emotion recognition in controls. tVNS seems to specifically alter early visual processing of stimuli of negative emotional valence in MDD. These findings suggest a potential therapeutic benefit of tVNS in adolescent MDD that requires further evaluation within clinical trials.
The synergetic effects of surface smoothing exhibited during the inductively coupled plasma reactive ion etching (ICP-RIE) of free-standing polycrystalline diamonds (PCDs) were investigated. Changing the assistive gas types generated variable surface oxidation states and chemical environments that resulted in different etching rates and surface morphologies. The main reaction bond mechanism (C–O) during ICP-RIE and the ratio of C–O–C/O–C=O associated with the existence of a uniform smooth surface with root mean square (RMS) roughness of 2.36 nm were observed. An optimal process for PCD smoothing at high etching rate (4.6 μm/min) was achieved as follows: 10% gas additions of CHF3 in O2 plasma at radio frequency power of 400 W. The further etched ultra-smooth surface with RMS roughness <0.5 nm at etching rate of 0.23 μm/min that being produced by transferring this optimum recipe on single crystal diamonds with surface patterns confirmed the effectiveness of the fast smoothing approach and its feasibility for diamond surface patterning.
Nanoparticles and nanopores of iron oxide were synthesized by electrochemical anodization, in an electrolytic medium of ammonium fluoride (NH4F), deionized water and ethylene glycol. After anodization, the Fe foils were annealed at 450 °C for 2 hours. Different anodization times and two concentrations of NH4F (0.1 M and 1.2 M) were evaluated, under static conditions at room temperature. Scanning Electron Microscopy showed nanopores (0.1 M) and nanoparticles (1.2 M). Eight vibration modes characteristic of α-Fe2O3 were found with Raman spectroscopy technique. Relationship between the modes Eu(LO) and 2Eu(LO) was found, therefore, their association with the disorder in the crystalline structure can be determined and it was also found that 2Eu(LO) intensity mode at a concentration of 1.2 M is larger than 0.1 M nanostructures, the FWHM of the A1g mode at 227 cm-1 corresponding to the Fe3+ ions and the Eg at 293 cm-1 mode caused by the O2- ions was also analyzed and founded that the crystalline structure of hematite can be determined by the A1g mode at 227 cm-1.
Graphene has been publicized as the game changing material of this millennium. As research continues to expand our knowledge of this 2D semimetal, the properties at the interface have become an increasingly important characteristic. Translating graphene’s strength at the nanoscale to the macroscale is suggested by functionalizing the graphene, creating a favourable interfacial morphology to adhere. An interfacial morphology that is able to form primary chemical bonds is ideal, providing the best mechanical property performance. We proposed a method of creating a graphene reinforced polymer matrix composite from flake mineral graphite in-situ, using high shear elongational flow to produces these conditions. In our process we were able to identify chemical bonding at graphene’s surface, which developed into newly created interfacial morphologies. These morphologies lead to an increase in mechanical properties while providing an improved stress transfer between graphene and its containing matrix. Our work sheds light on a solvent free route to scalable high strength graphene composites.
Neuroimaging visualizes and quantifies age-related changes in brain structure, function, cerebral blood flow, and cerebral metabolic health. MRI studies show reductions in both overall and regional brain volumes, but to a lesser extent than in Alzheimer’s disease. Those aging non-pathologically tend to have relative preservation of mesial temporal and enthorhinal brain areas. White matter changes are also common as shown by hyperintensities on fluid attenuated inversion recovery and other T2 MRI images, presumably as a result of co-morbities that increasingly occur with age. Diffusion tensor imaging shows reductions in white matter integrity, including white matter fiber counts and overall white matter volume, beginning in mid- to late life. The neural response during both rest and task performance also shows reduced activation of core task-related networks but expansion to include other region activation. Reduced cerebral blood volume and flow also occur, likely reflecting alterations in hemodynamic function due to cerebrovascular and cardiovascular changes. Cerebral metabolic changes on MR spectroscopy occur with reduced concentrations of GABA and other neurotransmitters, as well as markers of neuronal integrity. Myoinositol, a marker of glial activation, may be elevated, indicating neuroinflammation, though this effect is likely not ubiquitous in successful aging.
This chapter, reviews the basics of monitoring in children. The author provides a discussion on the utility of a host of invasive and non-invasive monitoring techniques from non-invasive blood pressure measurements to placement of umbilical lines. Most importantly, the chapter highlight the limitations of these monitoring devices in small children.
In this work, the anodization of grade 2 titanium was performed using a HCl-based electrolyte in order to obtain Titania nanostructures. Different glycerol concentrations were added to the HCl electrolyte to study the effect it has on the shape and density of the nanostructures, additionally, anodization time and voltage was also varied. The anodized samples were observed by SEM microscopy and studied by Raman spectroscopy and X-ray diffraction. Raman spectroscopy and XRD showed the formation of the anatase phase of the TiO2. By SEM it was possible to observe several changes in the shape of the structures, by adding glycerol ball-like structures were visible, anodization time did not change the shape of the nanostructures. However, the voltage variation showed a clear control on the shape of the structures, forming nanotubes at higher voltages. It was concluded that a better control of the shape and density of the nanostructures is achieved by adding glycerol, however, in order to overcome the resistance that the electrolyte brings, higher voltages are required.
Multi- and hyperspectral sensors in the visible to short-wave infrared (0.4–2.5 μm) are sensitive to spectral features caused by electronic charge transfer and transition metal crystal field band as well as molecular overtone absorptions. This chapter reviews several processing techniques used to map materials on planetary surfaces based on their reflectance spectra in this spectral region. Techniques that are reviewed include spectral matching in the form of spectral angle and spectral information divergence, linear and nonlinear spectral unmixing, partial unmixing/matched filters, and machine learning approaches in the form of self-organizing maps, neural network classification, and support vector machines.
Advanced spectroscopic sensors recently flown to the Moon have revealed unexpected discoveries about Earth’s nearest neighbor as well as provided detailed insights and constraints about how early crust evolves on an airless planetary body. Discussed here are (a) global assessment of the variety and distribution of major lunar mineral components and lithologies; (b) some of the remarkable new findings, such as the pervasive presence of OH across the surface and new rock types identified (Mg-spinel anorthosite) that are not identified in current lunar samples; and (c) expectations for the future as additional modern sensors provide a stronger foundation for remote compositional analysis of the Moon. Spectroscopic data continue to provide the cornerstone for identifying and understanding the regional and global character of lunar compositional variations and document key products and processes of crustal evolution.
This chapter reviews key findings from analyses of spectral reflectance measurements of Mercury taken by the MESSENGER mission. Mercury’s crust lacks the 1-µm crystal field absorption due to ferrous iron that is common on other silicate bodies, yet is unusually low in reflectance. The most likely darkening phase is carbon as graphite. Variations in reflectance and color reveal that volcanic plains averaging >5 km in thickness overlie graphite-rich low-reflectance material, which may have originated as a graphite flotation crust from a magma ocean. The one unambiguous absorption due to an oxidized transition metal, an ultraviolet oxygen–metal charge transfer band in bright, pyroclastic deposits, may originate by oxidation of carbon and sulfides, reducing 0.3–1 wt.% ferrous iron in silicates to a metallic state, unsaturating the very strong oxygen–metal charge transfer band.
Stand-off Raman spectroscopy is emerging as a critical new tool for planetary exploration. Mounted on a rover, a stand-off Raman system can be used to rapidly identify areas of interest for subsequent, synergistic investigations with other stand-off or close-up (arm-mounted) instruments; survey broad areas and perform reconnaissance tasks from a fixed location; and increase the efficiency of mission operations where targets of interest are in areas that are too hard to access for a rover. Not surprisingly, NASA’s next Mars mission will fly a stand-off Raman system as part of the SuperCam instrument package. This chapter reviews two stand-off Raman systems that paved the way for the development of new technologies and instrument architectures for robotic stand-off planetary exploration using Raman spectroscopy, including the SuperCam instrument suite.
A variety of features in the visible and near-infrared regions that are observed in remote sensing applications are the result of electronic transitions, typically involving cations of transition metals, most commonly Fe and Ti, or the molecular species S. The position and intensity of these features are sensitive not only to the particular cation, but also to its oxidation state, the particular phase in which it occurs, the geometric structure of the site that it occupies, and interactions between and among neighboring cations. Often these features are diagnostic for the host mineral.
The advent of multiple orbital and in situ missions to planetary bodies beyond Earth has enabled characterization of extraterrestrial shallow crustal processes. We describe examples of interpreting geochemical, isotopic, and radar properties from multiple remote datasets, supplemented with in situ observations from rovers and landers, meteorites, and lunar samples. Given the availability of distinct data types and the relevance to bulk-silicate bodies in the Solar System, we present five case studies for the Moon and Mars. The first involves lunar magmatic processes in relation to TiO2 and radargram-derived physical properties. Next, O and Fe isotope variations relative to the Mg number provide insight into the degree of fractional crystallization in lunar lava flows. Physical mixing of endmembers and chemical weathering processes in Gusev crater soil on Mars are discussed. Effective use of the Chemical Index of Alteration (CIA) is also considered by comparing mineralogic observations across Mars with terrestrial references. Lastly, the nature of bulk soil hydration on Mars is described by assessing chemical variations with Principal Component Analysis (PCA). This chapter describes in situ analyses and mapping across local and regional scales. Data synthesis also involves contrasting depth scales from tens of microns to multiple kilometers.
Thermal infrared data collected by the Thermal Emission Spectrometer (TES) and Thermal Emission Imaging System (THEMIS) instruments have significantly impacted the understanding of martian surface mineralogy. Spatial/temporal variations in igneous lithologies; the discovery of quartz, carbonates, and chlorides; and the widespread identification of amorphous, silica-enriched materials reveal a planet that has experienced a diversity of primary and secondary geo-logic processes including igneous crustal evolution, regional sedimentation, aqueous alteration, and glacial/periglacial activity.
Spectral modeling techniques have been developed for the analysis of planetary surfaces using large thermal infrared (TIR) spacecraft datasets. These techniques can be applied to three main spectral analysis problems: (1) correction for atmospheric effects for the recovery of surface emissivity; (2) isolation and separation of surface spectral endmembers for the characterization of surface mineralogy; and (3) determination of surface anisothermality for the retrieval of surface physical properties and correction for thermal emission in near-infrared spectral data. These modeling techniques have been extensively applied to martian and lunar spacecraft datasets, forming a basis for the retrieval of surface physical and compositional properties.
This chapter provides a brief review of missions using X-ray, gamma-ray, and neutron spectroscopy to determine the chemical composition of planetary surfaces. This chapter presents the history of planetary radiation measurements, including significant discoveries. Summary tables with links to the archived data provide a resource for readers interested in working in this field. Upcoming missions and possible future directions are described.
An ever-increasing number of laboratory facilities are enabling in situ spectral reflectance measurements of materials under conditions relevant to all the bodies in the Solar System, from Mercury to Pluto and beyond. Results derived from these facilities demonstrate that exposure of different materials to various planetary surface conditions can provide insights into the endogenic and exogenic processes that operate to modify their surface spectra, and their relative importance. Temperature, surface atmospheric pressure, atmospheric composition, radiation environment, and exposure to the space environment have all been shown to measurably affect reflectance and emittance spectra of a wide range of materials. Planetary surfaces are dynamic environments, and as our ability to reproduce a wider range of planetary surface conditions improves, so will our ability to better determine the surface composition of these bodies, and by extension, their geologic history.