Recent advances in nanotechnologies have prompted the need for tools to accurately and non-invasively manipulate individual nano-objects. Among the possible strategies, optical forces have been ...predicted to provide researchers with nano-optical tweezers capable of trapping a specimen and moving it in three dimensions. In practice, however, the combination of weak optical forces and photothermal issues has thus far prevented their experimental realization. Here, we demonstrate the first three-dimensional optical manipulation of single 50 nm dielectric objects with near-field nanotweezers. The nano-optical trap is built by engineering a bowtie plasmonic aperture at the extremity of a tapered metal-coated optical fibre. Both the trapping operation and monitoring are performed through the optical fibre, making these nanotweezers totally autonomous and free of bulky optical elements. The achieved trapping performances allow for the trapped specimen to be moved over tens of micrometres over a period of several minutes with very low in-trap intensities. This non-invasive approach is foreseen to open new horizons in nanosciences by offering an unprecedented level of control of nanosized objects, including heat-sensitive biospecimens.
Question Transcranial random noise stimulation (tRNS) is an innovative technique of non-invasive electrical stimulation with a handful of publications most of them investigating processes of the ...motor system. With respect to the auditory system only. Limited evidence is available for modulation of auditory processing in healthy controls and patients with chronic tinnitus. Here, we aimed to investigate the effects of tRNS over the auditory cortex on resting state and evoked activity in healthy subjects. Methods We used EEG to measure tRNS induced changes in resting state activity and in auditory steady state responses (ASSRs). Stimuli were 1000 Hz carrier frequency tones, amplitude modulated at 20 Hz and 40 Hz and applied in randomized order. Nineteen healthy subjects participated in a placebo-controlled randomized design study. Each subject received 20 min of high-frequency, low-frequency, and sham tRNS applied over auditory cortices with 2 mA, with a one week interval between the stimulation sessions. Results Data analysis is done at the moment of abstract submission. Thus, we hypothesize that we will be able to replicate previous findings that high-frequency tRNS will modulate the 40 Hz ASSR amplitude and the mean and variability of theta band power during resting state. Further analyses will aim at testing differences in the effects of high- and low-frequency tRNS. Conclusions Our findings of tRNS effects for processes of the auditory system will be discussed with respect to previous findings of tRNS effects on motor cortex excitability and to current concepts of tRNS mechanisms such as increase of stochastic resonance.
Polysulfobetaines in aqueous solution show upper critical solution temperature (UCST) behavior. We investigate here the representative of this class of materials, poly (
,
-dimethyl-
...-(3-methacrylamidopropyl) ammonio propane sulfonate) (PSPP), with respect to: (i) the dynamics in aqueous solution above the cloud point as function of NaBr concentration; and (ii) the swelling behavior of thin films in water vapor as function of the initial film thickness. For PSPP solutions with a concentration of 5 wt.%, the temperature dependence of the intensity autocorrelation functions is measured with dynamic light scattering as function of molar mass and NaBr concentration (0⁻8 mM). We found a scaling of behavior for the scattered intensity and dynamic correlation length. The resulting spinodal temperatures showed a maximum at a certain (small) NaBr concentration, which is similar to the behavior of the cloud points measured previously by turbidimetry. The critical exponent of susceptibility depends on NaBr concentration, with a minimum value where the spinodal temperature is maximum and a trend towards the mean-field value of unity with increasing NaBr concentration. In contrast, the critical exponent of the correlation length does not depend on NaBr concentration and is lower than the value of 0.5 predicted by mean-field theory. For PSPP thin films, the swelling behavior was found to depend on film thickness. A film thickness of about 100 nm turns out to be the optimum thickness needed to obtain fast hydration with H₂O.
Ore deposits are diverse with much of their diversity attributable to the complex interplay of ore-forming processes with a variety of geological environments, over a range of scales and both in ...space and time. This diversity makes it difficult for geoscientists to accurately predict the location of undiscovered ore deposits. Improving our understanding of the processes that are critical to ore deposit formation would help us to hone our predictive capabilities. However, this task is difficult to achieve as we cannot observe these genetic processes first-hand and different parameters and ingredients are important at different scales. Modelling offers a means of simulating and analysing ore-forming processes and their mappable expressions. This knowledge can then be used to build a predictive model by translating key process components into spatial proxies that can be mapped or recognized in mineral exploration data. Modelling and analysis of ore-forming processes are therefore critical for the future success of mineral exploration. Currently underutilized in exploration targeting, the application of statistical and mathematical concepts can help steer geoscientists towards a better understanding of the complex geological processes critical in the formation of mineral deposits and, ultimately, improved exploration success rates. This editorial article presents a brief introduction to the main concepts that support a collection of articles published in a virtual special issue (VSI) of Ore Geology Reviews entitled “Spatial modelling and analysis of ore-forming processes in mineral exploration targeting”. The articles examine three critical themes: (1) Translating the expressions of ore-forming processes and critical parameters of mineral systems into mappable spatial proxies; (2) identifying mineral deposit footprints through geochemical and geophysical data analysis; and (3) targeting and improving the discovery chance of mineral deposits by way of spatial data analysis.
The FlexiProb project is a joint effort of three soft matter groups at the Universities of Bielefeld, Darmstadt, and Munich with scientific support from the European Spallation Source (ESS), the ...small-K advanced diffractometer (SKADI) beamline development group of the Jülich Centre for Neutron Science (JCNS), and the Heinz Maier-Leibnitz Zentrum (MLZ). Within this framework, a flexible and quickly interchangeable sample carrier system for small-angle neutron scattering (SANS) at the ESS was developed. In the present contribution, the development of a sample environment for the investigation of soft matter thin films with grazing-incidence small-angle neutron scattering (GISANS) is introduced. Therefore, components were assembled on an optical breadboard for the measurement of thin film samples under controlled ambient conditions, with adjustable temperature and humidity, as well as the optional in situ recording of the film thickness via spectral reflectance. Samples were placed in a 3D-printed spherical humidity metal chamber, which enabled the accurate control of experimental conditions via water-heated channels within its walls. A separately heated gas flow stream supplied an adjustable flow of dry or saturated solvent vapor. First test experiments proved the concept of the setup and respective component functionality.
Here, we propose a new concept, ‘new generation artificial intelligence (AI) algorithms for mineral prospectivity mapping (MPM)’, which places greater emphasis on interpretability and domain ...cognitive consistency than the established machine learning (ML) algorithms pertaining to MPM. More specifically, the newly proposed algorithms are designed to (1) allow for the integration of prior geological and expert knowledge into AI models at various stages of the modeling process; (2) offer a degree of transparency about the information transfer process while also improving analysis and evaluation of input features; (3) extract new prospecting information, thereby further enhancing mineral exploration targeting and promoting the advancement of mineral deposit knowledge. We also propose several essential strategies to improve the MPM workflow, including: (1) building a robust conceptual model of the target commodity and deposit type, (2) translating the conceptual model into a practical exploration targeting model, (3) constructing a comprehensive and high-quality geodatabase, and (4) identifying relevant targeting parameters and further integrating them using the newly proposed algorithms. The key motivation behind the development of the new generation AI algorithms for MPM is to improve mineral exploration success rates, a prerequisite to addressing anticipated shortages across a range of critical metallic elements. Drawing from the insights gained in this study, we believe that prioritizing the development of a graph-based AI approach in conjunction with geological expert knowledge would be a valuable direction for future research for MPM.
Background Prefrontal and temporoparietal repetitive transcranial magnetic stimulation (rTMS) in chronic tinnitus showed significant but only moderate effectiveness with high inter-individual ...variability in treatment response. This study was designed to proof the feasibility of an individualized fronto-temporal rTMS paradigm. Methods During the first session of our standard two-week rTMS setting we applied different protocols to the left and right temporoparietal and dorsolateral prefrontal cortex (DLPFC) in 25 tinnitus patients. In each protocol 200 pulses (except for 1 Hz frequency containing 50 pulses) were applied at frequencies of 1 Hz, 5 Hz, 10 Hz, 20 Hz, cTBS, sham (continuous theta burst stimulation). Patients reporting immediate tinnitus reduction were treated in an individualized manner applying a combined protocol consisting of the most effective frontal and the most effective temporoparietal stimulation protocol. Those patients who did not improve after the test session were treated with a standard fronto-temporoparietal protocol. Results Almost half of the patients (12 out of 25) reported immediate tinnitus reduction in the test session. In this group the mean pre-to-post-treatment amelioration in the tinnitus questionnaire was 8.6 ± 8.9 whereas the improvement was only 1.5 ± 8.5 in those patients who did not respond to the test session. Treatment outcome remained stable over a follow-up period of ten weeks. Discussion Individualized rTMS was shown to be feasible and effective in chronic tinnitus and might provide a basis for a “tailored” application of rTMS in tinnitus and other neuropsychiatric disorders.
Question Non-invasive brain stimulation can modify phantom sounds for longer periods by modulating neural activity and putatively inducing regional neuroplastic changes ( Elgoyhen, 2015 ). However, ...treatment response is limited and there are no good demographic or clinical predictors for treatment outcome ( Lehner, 2012 ). We used state-of-the-art voxel-based morphometry (VBM) to investigate whether transcranial magnetic stimulation-induced neuroplasticity determines therapeutic outcome. Methods Sixty subjects chronically experiencing phantom sounds (i.e., tinnitus) received repetitive transcranial magnetic stimulation (rTMS) of left dorsolateral prefrontal and temporal cortex according to a protocol that has been shown to yield a significantly higher number of treatment responders than sham stimulation and previous stimulation protocols ( Langguth, 2014 ). Structural magnetic resonance imaging was performed before and after rTMS. In VBM whole-brain analyses ( p < 0.05, FWE corrected), we assessed longitudinal gray matter changes as well as structural connectivity between the ensuing regions ( Gerber, 2014 ). Results We observed longitudinal mesoscopic gray matter changes of left dorsolateral prefontal (DLPFC), left operculo-insular, and right inferior temporal cortex (ITC) in responders ( N = 22) but not non-responders ( N = 38), as indicated by a group ×time interaction and post-hoc tests (Fig. 1 ). These results were not influenced by age, sex, hearing loss nor by tinnitus laterality, duration, and severity at baseline. Furthermore, we found robust DLPFC-insula and insula-ITC connectivity in responders, while only relatively weak DLPFC-insula connectivity and no insula-ITC connectivity could be demonstrated in non-responders (Fig. 2 ). Conclusions Our results reinforce the implication of non-auditory brain regions in phantom sounds and suggest the dependence of therapeutic response on their neuroplastic capabilities. The latter in turn may depend on (differences in) their individual structural connectivity.
Background Interference of ongoing neuronal activity and brain stimulation motivated this study to prove the concept of a combined treatment approach integrating repetitive transcranial magnetic ...stimulation (rTMS) and relaxation techniques in patients with chronic tinnitus. Methods Forty-two patients received rTMS consisting of ten sessions of high-frequency left dorsolateral prefrontal cortex followed by low-frequency left temporo-parietal cortex stimulation in this one-arm proof-of-concept study. During low-frequency stimulation patients listened to different kinds of relaxation audios selected according individual preferences (classical music; instructions to muscle or breath relaxation, imaginary journey or hypnosis). Variables of interest were tinnitus questionnaires, tinnitus numeric rating scales, depressivity, and quality of life. Results were compared to results of historical control groups having received the same rTMS protocol (active control) and sham treatment (placebo) without relaxation techniques. Results Drop-outs and adverse events were low. Responder rates (reduction in tinnitus questionnaire (TQ) score by at least 5 points ten weeks after treatment) were 44.7% in the study, 27.8% in the active control group, and 21.7% in the placebo group, differing between groups on a near-significant level. Combination of rTMS and relaxation showed higher amelioration in the tinnitus handicap inventory questionnaire (THI) in contrast to rTMS alone. Deepness of relaxation during rTMS and selection of active relaxation vs. passive listening to music predicted larger reductions in the TQ-score. All remaining secondary outcomes turned out non-significant. Discussion Combining rTMS and relaxation techniques has proven to be a safe, feasible and promising approach to enhance rTMS treatment effects in chronic tinnitus.
The European Spallation Source (ESS), which is under construction in Lund (Sweden), will be the leading and most brilliant neutron source and aims at starting user operation at the end of 2023. Among ...others, two small angle neutron scattering (SANS) machines will be operated. Due to the high brilliance of the source, it is important to minimize the downtime of the instruments. For this, a collaboration between three German universities and the ESS was initialized to develop and construct a unified sample environment (SE) system. The main focus was set on the use of a robust carrier system for the different SEs, which allows setting up experiments and first prealignment outside the SANS instruments. This article covers the development and construction of a SE for SANS experiments with foams, which allows measuring foams at different drainage states and the control of the rate of foam formation, temperature, and measurement position. The functionality under ESS conditions was tested and neutron test measurement were carried out.
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