Characterization of Carbon-Contaminated B4C-Coated Optics after Chemically Selective Cleaning with Low-Pressure RF Plasma

Boron carbide (B4C) is one of the few materials that is expected to be mostly resilient with respect to the extremely high brilliance of the photon beam generated by free electron lasers (FELs) and is thus of considerable interest for optical applications in this field. However, as in the case of many other optics operated at modern light source facilities, B4C-coated optics are subject to ubiquitous carbon contaminations. These contaminations represent a serious issue for the operation of high performance FEL beamlines due to severe reduction of photon flux, beam coherence, creation of destructive interference, and scattering losses. A variety of B4C cleaning technologies were developed at different laboratories with varying success. We present a study regarding the low-pressure RF plasma cleaning of carbon contaminated B4C test samples via inductively coupled O2/Ar, H2/Ar, and pure O2 RF plasma produced following previous studies using the same IBSS GV10x downstream plasma source. Results regarding the chemistry, morphology as well as other aspects of the B4C optical coating before and after the plasma cleaning are reported. We conclude from these comparative plasma processes that pure O2 feedstock plasma only exhibits the required chemical selectivity for maintaining the integrity of the B4C optical coating.Comment: 27 pages, 15 figure

Hybrid magnetic iron oxide nanoparticles with tunable field-directed self-assembly

We describe the synthesis of hybrid magnetic ellipsoidal nanoparticles that consist of a mixture of two different iron oxide phases, hematite (α-Fe2O3) and maghemite (γ- Fe2O3), and characterize their magnetic field-driven self-assembly. We demonstrate that the relative amount of the two phases can be adjusted in a continuous way by varying the reaction time during the synthesis, leading to strongly varying magnetic properties of the particles. Not only does the saturation magnetization increase dramatically as the composition of the spindles changes from hematite to maghemite, but also the direction of the induced magnetic moment changes from being parallel to the short axis of the spindle to being perpendicular to it. The magnetic dipolar interaction between the particles can be further tuned by adding a screening silica shell. Small-angle X-ray scattering (SAXS) experiments reveal that at high magnetic field, magnetic dipole–dipole interaction forces the silica coated particles to self- assemble into a distorted hexagonal crystal structure at high maghemite content. However, in the case of uncoated maghemite particles, the crystal structure is not very prominent. We interpret this as a consequence of the strong dipolar interaction between uncoated spindles that then become arrested during field-induced self- assembly into a structure riddled with defects

The Ultra-Potent and Selective TLR8 Agonist VTX-294 Activates Human Newborn and Adult Leukocytes

Background: Newborns display distinct immune responses that contribute to susceptibility to infection and reduced vaccine responses. Toll-like receptor (TLR) agonists may serve as vaccine adjuvants, when given individually or in combination, but responses of neonatal leukocytes to many TLR agonists are diminished. TLR8 agonists are more effective than other TLR agonists in activating human neonatal leukocytes in vitro, but little is known about whether different TLR8 agonists may distinctly activate neonatal leukocytes. We characterized the in vitro immuno-stimulatory activities of a novel benzazepine TLR8 agonist, VTX-294, in comparison to imidazoquinolines that activate TLR8 (R-848; (TLR7/8) CL075; (TLR8/7)), with respect to activation of human newborn and adult leukocytes. Effects of VTX-294 and R-848 in combination with monophosphoryl lipid A (MPLA; TLR4) were also assessed. Methods: TLR agonist specificity was assessed using TLR-transfected HEK293 cells expressing a NF-κB reporter gene. TLR agonist-induced cytokine production was measured in human newborn cord and adult peripheral blood using ELISA and multiplex assays. Newborn and adult monocytes were differentiated into monocyte-derived dendritic cells (MoDCs) and TLR agonist-induced activation assessed by cytokine production (ELISA) and co-stimulatory molecule expression (flow cytometry). Results: VTX-294 was ∼100x more active on TLR8- than TLR7-transfected HEK cells (EC50, ∼50 nM vs. ∼5700 nM). VTX-294-induced TNF and IL-1β production were comparable in newborn cord and adult peripheral blood, while VTX-294 was ∼ 1 log more potent in inducing TNF and IL-1β production than MPLA, R848 or CL075. Combination of VTX-294 and MPLA induced greater blood TNF and IL-1β responses than combination of R-848 and MPLA. VTX-294 also potently induced expression of cytokines and co-stimulatory molecules HLA-DR and CD86 in human newborn MoDCs. Conclusions: VTX-294 is a novel ultra-potent TLR8 agonist that activates newborn and adult leukocytes and is a candidate vaccine adjuvant in both early life and adulthood

Reflection on multilayer mirrors beam profile and coherence properties

The main advantage of Bragg reflection from a multilayer mirror as a monochromator for hard X rays, is the higher photon flux density because of the larger spectral bandpass compared with crystal lattice reflection. The main disadvantage lies in the strong modulations of the reflected beam profile. This is a major issue for micro imaging applications, where multilayer based monochromators are frequently employed to deliver high photon flux density. A subject of particular interest is the origin of the beam profile modifications, namely the irregular stripe patterns, induced by the reflection on a multilayer. For multilayer coatings in general it is known that the substrate and its surface quality significantly influence the performance of mirrors, as the coating reproduces to a certain degree the roughness and shape of the substrate. This proceedings article reviews recent experiments that indicate potential options for producing wave front preserving multilayer mirrors, as well as new details on the particular mirrors our group has extensively studied in the pas

Conceptualizing values as part of a dynamic multilevel world

Includes bibliographical references.2015 Summer.Humans are engaged in complex relationships of adaptation and change with the environment, each affecting one another. These relationships (i.e., feedback loops) necessitate an increased understanding of the different components of social-ecological systems. However, these systems appear to operate differently depending on the levels and scales under investigation, making it difficult to fully conceptualize these interconnected phenomena as well as raising important questions. We narrow our focus on two specific areas of inquiry in the interest of explicating factors that influence social values, which in turn lead to the attitudes and behaviors that can either drive or alleviate the many environmental challenges we face. First, how might macro processes of social change at different levels affect individual-level thought, and what might this mean for biodiversity conservation and environmental protection? Second, can internal human cognitions transform into widespread societal beliefs about how the environment, including wildlife, should be treated? This dissertation presents two manuscripts designed to contribute to these areas of inquiry by considering how values are influenced by processes at different levels on a geopolitical scale, and how those values shape levels of cognition within individuals (an internal cognitive scale). The first chapter specifically focuses on understanding how socioeconomic advances at the county-level within the state of Washington are influencing new value priorities, and how these values lead to support for biodiversity conservation of species irrespective of human needs. For example, higher levels of income, education, and urbanization at both individual and county levels were associated with higher degrees of mutualism, a value orientation that prioritizes the needs of wildlife as similar to the needs of humans. Indeed, we found mutualism to be positively associated with support for wolves (Canis lupis) recolonizing the state despite the potential for livestock predation and concern for human safety. Results also indicate that these new value priorities can lead to social conflict among different segments of the public based on beliefs about how wildlife should be managed. This work demonstrates several key findings. First, broad changes in social systems lead to a fundamental shift in social values in such a way that clearly indicates social-ecological context matters. Second, these values lead to predictable patterns of response to actions that promote biodiversity conservation. However, those patterns of response vary across the landscape, providing further evidence of cross-level and cross-scale dynamics within systems. The second article casts social values as actors in a different, but equally important systems view complete with feedback loops. Specifically, social values are depicted as subject to the upward processes of emergence (micro-to-macro level) and the downward processes of immergence (macro-to-micro level). Our conceptualization acknowledges values as phenomena that emerge from individuals who are in turn shaped by pervasive social-ecological conditions (e.g., warfare, mass migrations, disease spread). Although processes of emergence are not directly studied in this manuscript, immergence is explored in two ways: (1) the effect of socioeconomic advances at a state level on individual expressions of postmaterialist values (values that tend to focus on the needs of others outside of self), and (2) the existence of widespread environmental attitudes associated with a prevalence of postmaterialist values. Only support for the second pathway of immergence was found, suggesting that individuals with postmaterialist values do indeed support protection of the environment, including wildlife, even at the expense of human interests such as economic development and recreation behaviors. In total, this dissertation is intended to provide a deeper look at the feedback loops between different levels of cognition and the world in which we live in the hopes of informing solutions to the grave environmental challenges we face

Force Amplitude Modulation of Tongue and Hand Movements

Rapid, precise movements of the hand and tongue are necessary to complete a wide range of tasks in everyday life. However, the understanding of normal neural control of force production is limited, particularly for the tongue. Functional neuroimaging studies of incremental hand pressure production in healthy adults revealed scaled activations in the basal ganglia, but no imaging studies of tongue force regulation have been reported. The purposes of this study were (1) to identify the neural substrates controlling tongue force for speech and nonspeech tasks, (2) to determine which activations scaled to the magnitude of force produced, and (3) to assess whether positional modifications influenced maximum pressures and accuracy of pressure target matching for hand and tongue movements. Healthy older adults compressed small plastic bulbs in the oral cavity (for speech and nonspeech tasks) and in the hand at specified fractions of maximum voluntary contraction while magnetic resonance images were acquired. Volume of interest analysis at individual and group levels outlined a network of neural substrates controlling tongue speech and nonspeech movements. Repeated measures analysis revealed differences in percentage signal change and activation volume across task and effort level in some brain regions. Actual pressures and the accuracy of pressure matching were influenced by effort level in all tasks and body position in the hand squeeze task. The current results can serve as a basis of comparison for tongue movement control in individuals with neurological disease. Group differences in motor control mechanisms may help explain differential response of limb and tongue movements to medical interventions (as occurs in Parkinson disease) and ultimately may lead to more focused intervention for dysarthria in several conditions such as PD

Neural Control of Tongue Movements Across Effort Levels

Background A hallmark of Parkinson’s disease (PD) is a mismatch between the perceived effort and actual forces exerted during functional activities such as speech. Current evidence supports therapy to help reset this perception of effort, but the neurological underpinnings of such treatments are unclear. This study examined brain activity during tongue movements performed at varying levels of effort to determine (1) which brain areas are involved in each task, and (2) which areas, if any, scale in activation according to effort level. These results, considered with the neurological changes associated with PD, can be used to develop and refine treatment techniques for PD. Methods The structural and functional magnetic resonance (MR) data were previously collected from 20 healthy 40-60 year-old adults. Participants performed phoneme (speech sound) repetition and isometric tongue-to-palate presses while MR images were obtained. Ten datasets underwent whole brain analysis via SPM software to create a mask of shared activation. This mask was applied to the remaining 10 datasets to extract scaling data. Results/Conclusion Multiple areas including sensory, motor, and insular cortices were active during study tasks. The only area exhibiting statistically significant scaling was the left secondary sensorimotor cortex during the isometric tongue press. This area has been linked to processing of light touch, tactile attention, and somatosensory integration for voluntary skeletal movements. Additional activations were noted in the right insula, which is associated with motor control of speech and swallowing movements, as well as self-awareness

Daily Phonatory Activity of Individuals with Parkinson’s Disease

Purpose This study evaluated the amount of phonatory activity of Persons with Parkinson disease (PwPD) compared to adults without Parkinson’s disease measured over 3 days. The relationship between the amount of phonatory activity and Voice Handicap Index (VHI) total score was assessed as were differences in voicing activity across 3 days of data collection. Methods Fifteen PwPD receiving dopaminergic medication and fifteen age and sex matched adults without Parkinson’s disease completed the VHI and then wore a VocaLog vocal monitor (VM) for 3 consecutive days. From the VM data, the number of 1-second windows with dB sound pressure level \u3e 0 were summed as a measure of phonatory activity (PA) and reported relative to the time the VM was worn (%PA). Results The percentage of time the VM was worn did not differ between groups or across days. The PwPD had statistically significantly fewer minutes of PA per day than controls (F = 21.782, P \u3c 0.001) by 54 minutes on average. The %PA also differed significantly (F = 31.825, P \u3c 0.001) with a mean of 11.1% for PwPD and 18.6% for controls. Neither PA nor %PA differed across the 3 days of vocal monitoring. VHI total score was significantly correlated with PA (r = -0.436, P = 0.016) and %PA (r = -0.534, P = 0.002) for all participants. Conclusions The results indicate that PwPD engaged in less verbal communication in their daily environment compared to adults without Parkinson’s disease. The findings support reports in the literature indicating that PwPD often have reduced communication participation. Measures such as %PA could serve as a quantifiable metric in future studies assessing communication changes in PwPD as a function of disease progression or therapeutic interventions