Reward Circuit Local Field Potential Modulations Precede Risk Taking.

Risk taking behavior is a symptom of multiple neuropsychiatric disorders and often lacks effective treatments. Reward circuitry regions including the amygdala, orbitofrontal cortex, insula, and anterior cingulate have been implicated in risk-taking by neuroimaging studies. Electrophysiological activity associated with risk taking in these regions is not well understood in humans. Further characterizing the neural signalling that underlies risk-taking may provide therapeutic insight into disorders associated with risk-taking. Eleven patients with pharmacoresistant epilepsy who underwent stereotactic electroencephalography with electrodes in the amygdala, orbitofrontal cortex, insula, and/or anterior cingulate participated. Patients participated in a gambling task where they wagered on a visible playing card being higher than a hidden card, betting $5 or $20 on this outcome, while local field potentials were recorded from implanted electrodes. We used cluster-based permutation testing to identify reward prediction error signals by comparing oscillatory power following unexpected and expected rewards. We also used cluster-based permutation testing to compare power preceding high and low bets in high-risk (<50% chance of winning) trials and two-way ANOVA with bet and risk level to identify signals associated with risky, risk averse, and optimized decisions. We used linear mixed effects models to evaluate the relationship between reward prediction error and risky decision signals across trials, and a linear regression model for associations between risky decision signal power and Barratt Impulsiveness Scale scores for each patient. Reward prediction error signals were identified in the amygdala (p=0.0066), anterior cingulate (p=0.0092), and orbitofrontal cortex (p=6.0E-4, p=4.0E-4). Risky decisions were predicted by increased oscillatory power in high-gamma frequency range during card presentation in the orbitofrontal cortex (p=0.0022), and by increased power following bet cue presentation across the theta-to-beta range in the orbitofrontal cortex ( p =0.0022), high-gamma in the anterior cingulate ( p =0.0004), and high-gamma in the insula ( p =0.0014). Risk averse decisions were predicted by decreased orbitofrontal cortex gamma power ( p =2.0E-4). Optimized decisions that maximized earnings were preceded by decreases within the theta to beta range in orbitofrontal cortex ( p =2.0E-4), broad frequencies in amygdala ( p =2.0E-4), and theta to low-gamma in insula ( p =4.0E-4). Insula risky decision power was associated with orbitofrontal cortex high-gamma reward prediction error signal ( p =0.0048) and with patient impulsivity ( p =0.00478). Our findings identify and help characterize reward circuitry activity predictive of risk-taking in humans. These findings may serve as potential biomarkers to inform the development of novel treatment strategies such as closed loop neuromodulation for disorders of risk taking.

Oxidation behavior and atomic structural transition of size-selected coalescence-resistant tantalum nanoclusters.

Herein a series of size-selected TaN(N = 147, 309, 561, 923, 1415, 2057, 6525, 10 000, 20 000) clusters are generated using a gas-phase condensation cluster beam source equipped with a lateral time-of-flight mass-selector. Aberration-corrected scanning transmission electron microscopy (AC-STEM) imaging reveals good thermal stability of TaNclusters in this study. The oxidation-induced amorphization is observed from AC-STEM imaging and further demonstrated through x-ray photoelectron spectroscopy and energy-dispersive spectroscopy. The oxidized Ta predominantly exists in the +5 oxidation state and the maximum spontaneous oxidation depth of the Ta cluster is observed to be 5 nm under prolonged atmosphere exposure. Furthermore, the size-dependent sintering and crystallization processes of oxidized TaNclusters are observed with anin situheating technique, and eventually, ordered structures are restored. As the temperature reaches 1300 °C, a fraction of oxidized Ta309clusters exhibit decahedral and icosahedral structures. However, the five-fold symmetry structures are absent in larger clusters, instead, these clusters exhibit ordered structures resembling those of the crystalline Ta2O5films. Notably, the sintering and crystallization process occurs at temperatures significantly lower than the melting point of Ta and Ta2O5, and the ordered structures resulting from annealing remain well-preserved after six months of exposure to ambient conditions.

CACNN: Capsule Attention Convolutional Neural Networks for 3D Object Recognition.

Recently, view-based approaches, which recognize a 3D object through its projected 2-D images, have been extensively studied and have achieved considerable success in 3D object recognition. Nevertheless, most of them use a pooling operation to aggregate viewwise features, which usually leads to the visual information loss. To tackle this problem, we propose a novel layer called capsule attention layer (CAL) by using attention mechanism to fuse the features expressed by capsules. In detail, instead of dynamic routing algorithm, we use an attention module to transmit information from the lower level capsules to higher level capsules, which obviously improves the speed of capsule networks. In particular, the view pooling layer of multiview convolutional neural network (MVCNN) becomes a special case of our CAL when the trainable weights are chosen on some certain values. Furthermore, based on CAL, we propose a capsule attention convolutional neural network (CACNN) for 3D object recognition. Extensive experimental results on three benchmark datasets demonstrate the efficiency of our CACNN and show that it outperforms many state-of-the-art methods.

Long-term spatiotemporal variations in surface NO2 for Beijing reconstructed from surface data and satellite retrievals.

Remote sensing data from the Ozone Monitoring Instrument (OMI) and the TROPOspheric Monitoring Instrument (TROPOMI) play important roles in estimating surface nitrogen dioxide (NO2), but few studies have compared their differences for application in surface NO2 reconstruction. This study aims to explore the effectiveness of incorporating the tropospheric NO2 vertical column density (VCD) from OMI and TROPOMI (hereafter referred to as OMI and TROPOMI, respectively, for conciseness) for deriving surface NO2 and to apply the resulting data to revisit the spatiotemporal variations in surface NO2 for Beijing over the 2005-2020 period during which there were significant reductions in nitrogen oxide emissions. In the OMI versus TROPOMI performance comparison, the cross-validation R2 values were 0.73 and 0.72, respectively, at 1 km resolution and 0.69 for both at 100 m resolution. The comparisons between satellite data sources indicate that even though TROPOMI has a finer resolution it does not improve upon OMI for deriving surface NO2 at 1 km resolution, especially for analyzing long-term trends. In light of the comparison results, we used a hybrid approach based on machine learning to derive the spatiotemporal distribution of surface NO2 during 2005-2020 based on OMI. We had novel, independent passive sampling data collected weekly from July to September of 2008 for hindcasting validation and found a spatiotemporal R2 of 0.46 (RMSE = 7.0 ppb). Regarding the long-term trend of surface NO2, the level in 2008 was obviously lower than that in 2007 and 2009, as expected, which was attributed to pollution restrictions during the Olympic Games. The NO2 level started to steadily decline from 2015 and fell below 2008's level after 2017. Based on OMI, a long-term and fine-resolution surface NO2 dataset was developed for Beijing to support future environmental management questions and epidemiological research.

Influence of ligands on the optical properties of rod-shaped Au25 nanoclusters.

In this study, we successfully synthesized rod-shaped [Au25(PPh3)10(S-Adm)5Cl2]2+ nanoclusters using kinetic controls. The complete molecular structure was determined by single-crystal X-ray crystallography and electrospray ionization mass spectrometry. In comparison with the previously reported [Au25(PPh3)10(PET)5Cl2]2+ clusters, both nanoclusters have an icosahedral composition of Au13 linked by Au atoms that share a vertex, but [Au25(PPh3)10(S-Adm)5Cl2]2+ clusters appear elongated due to the rigidity of adamantane. We conducted ultraviolet-visible spectrophotometry (UV-vis) measurements of [Au25(PPh3)10(PET)5Cl2]2+ and [Au25(PPh3)10(S-Adm)5Cl2]2+ in dichloromethane solvent to elucidate the modulation of the cluster properties of different ligands. The lowest energy absorption peak of [Au25(PPh3)10(S-Adm)5Cl2]2+ shifted to lower energies compared to the [Au25(PPh3)10(PET)5Cl2]2+ clusters in UV-vis measurements. Temperature-dependent absorption measurements revealed that [Au25(PPh3)10(S-Adm)5Cl2]2+ clusters were less affected by temperature compared to [Au25(PPh3)10(PET)5Cl2]2+. This result is attributed to the exciton phonon coupling of [Au25(PPh3)10(S-Adm)5Cl2]2+ clusters being weaker than [Au25(PPh3)10(PET)5Cl2]2+ clusters. Furthermore, the absorption spectra of [Au25(PPh3)10(PET)5Cl2]2+ and [Au25(PPh3)10(S-Adm)5Cl2]2+ clusters were measured using different types of solutions, and it was found that the lowest energy absorption peaks of [Au25(PPh3)10(S-Adm)5Cl2]2+ were shifted and affected by the solution at room temperature, which suggested that the [Au25(PPh3)10(S-Adm)5Cl2]2+ clusters with solution hydrogen bonds also interacted strongly at room temperature. Theoretical calculations show that changes in ligands affect the differences in the molecular orbitals and structures of the clusters, which cause changes in the optical properties.

Corticostriatal beta oscillation changes associated with cognitive function in Parkinson's disease.

Cognitive impairment is the most frequent non-motor symptom in Parkinson's disease and is associated with deficits in a number of cognitive functions including working memory. However, the pathophysiology of Parkinson's disease cognitive impairment is poorly understood. Beta oscillations have previously been shown to play an important role in cognitive functions including working memory encoding. Decreased dopamine in motor cortico-striato-thalamo-cortical (CSTC) circuits increases the spectral power of beta oscillations and results in Parkinson's disease motor symptoms. Analogous changes in parallel cognitive CSTC circuits involving the caudate and dorsolateral prefrontal cortex (DLPFC) may contribute to Parkinson's disease cognitive impairment. The objective of our study is to evaluate whether changes in beta oscillations in the caudate and DLPFC contribute to cognitive impairment in Parkinson's disease patients. To investigate this, we used local field potential recordings during deep brain stimulation surgery in 15 patients with Parkinson's disease. Local field potentials were recorded from DLPFC and caudate at rest and during a working memory task. We examined changes in beta oscillatory power during the working memory task as well as the relationship of beta oscillatory activity to preoperative cognitive status, as determined from neuropsychological testing results. We additionally conducted exploratory analyses on the relationship between cognitive impairment and task-based changes in spectral power in additional frequency bands. Spectral power of beta oscillations decreased in both DLPFC and caudate during working memory encoding and increased in these structures during feedback. Subjects with cognitive impairment had smaller decreases in caudate and DLPFC beta oscillatory power during encoding. In our exploratory analysis, we found that similar differences occurred in alpha frequencies in caudate and theta and alpha in DLPFC. Our findings suggest that oscillatory power changes in cognitive CSTC circuits may contribute to cognitive symptoms in patients with Parkinson's disease. These findings may inform the future development of novel neuromodulatory treatments for cognitive impairment in Parkinson's disease.

A Low-Cost Liquid-Phase Method of Synthesizing High-Performance Li6PS5Cl Solid-Electrolyte.

Li6PS5Cl is an extensively studied sulfide-solid-electrolyte for developing all-solid-state lithium batteries. However, its practical application is hindered by the high cost of its raw material lithium sulfide (Li2S), the difficulty in its massive production, and its substandard performance. Herein we report an economically viable and scalable method, denoted as "de novo liquid phase method", which enables in synthesizing high-performance Li6PS5Cl without using commercial Li2S but instead in situ making Li2S from cheap materials of lithium chloride (LiCl) and sodium sulfide. LiCl, a raw material needed for making both Li2S and Li6PS5Cl, can be added at a full-scale in the beginning and unrequired to separate when making the intermediate Li3PS4. Such a consecutive feature makes this method time-efficient; and the excess amount of LiCl in the step of making Li2S also facilitates removing the byproduct of sodium chloride via the common ion effect. The materials cost of this method for Li6PS5Cl is ∼ $55/kg, comparable with the practical need of $50/kg. Moreover, the obtained Li6PS5Cl shows high ionic conductivity and outstanding cyclability in full battery tests, that is, ∼2 mS/cm and >99.8% retention for 400+ cycles at 1 C, respectively. Thus, this innovative method is expected to pave the way to develop practical sulfide-solid-electrolytes for all-solid-state lithium batteries.

Ti-substituted O3-type layered oxide cathode material with high-voltage stability for sodium-ion batteries.

O3-type layered transition metal oxides (NaxTMO2) have attracted extensive attention as a promising cathode material for sodium-ion batteries because of their high capacity. However, the irreversible phase transition especially cycled under high voltage remains a concerning challenge for NaxTMO2. Herein, a Ti-substituted NaNi0.5Co0.2Mn0.3O2 cathode with strongly suppressed phase transition and enhanced storage stability is investigated. The Ti substitution effectively inhibits the irreversible phase transition and alleviates the structural change even charged to 4.3 V during the repeated Na+ deintercalation process. After storing in air or water, the original O3 phase structure of the material is integrally maintained without the generation of impurity phase. As a result, the as-prepared material shows excellent long-term cycle stability and rate performance when charged to a high voltage of 4.3 V.

Green synthesis of the battery material lithium sulfide via metathetic reactions.

We report a synthesis of lithium sulfide, the cost-determining material for making sulphide solid electrolytes (SSEs), via spontaneous metathesis reactions between lithium salts (halides and nitrate) and sodium sulfide. This innovative method is economical, scalable and green. It will pave the way to developing practical SSE-based solid-state lithium batteries.

Role of Residual Li and Oxygen Vacancies in Ni-rich Cathode Materials.

Residual Li and oxygen vacancies in Ni-rich cathode materials have a great influence on electrochemical performance, yet their role is still poorly understood. Herein, by simply adjusting the oxygen flow during the high-temperature sintering process, some Li2O can be carried into the exhaust gas and the contents of residual Li and oxygen vacancies in LiNi0.825Co0.115Mn0.06O2 cathodes can be accurately controlled. Residual Li reduces the surficial Li+ diffusion coefficient, thereby limiting the rate property of the cathode. Oxygen vacancies affect the oxygen release energy in the crystal, and the lowest oxygen release energy is found at an oxygen vacancy concentration of 8.35%, resulting in an unstable structure and thereby poor cycle performance. The Ni-rich cathode with low residual Li and oxygen vacancy contents exhibits superior capacity retention (89.55 and 77.66%) at 2C after 300 cycles between 2.7-4.3 and 2.7-4.5 V. These findings clarify the role of residual Li and oxygen vacancies in Ni-rich cathode materials and provide a simple way to obtain high-performance Ni-rich cathodes for high-energy-density Li-ion batteries.

Preparation and Thermoelectric Characteristics of ITO/PtRh:PtRh Thin Film Thermocouple.

Thin film thermocouples (TFTCs) can provide more precise in situ temperature measurement for aerospace propulsion systems without disturbance of gas flow and surface temperature distribution of the hot components. ITO/PtRh:PtRh TFTC with multilayer structure was deposited on alumina ceramic substrate by magnetron sputtering. After annealing, the TFTC was statically calibrated for multiple cycles with temperature up to 1000 °C. The TFTC with excellent stability and repeatability was realized for the negligible variation of EMF in different calibration cycles. It is believed that owing to oxygen diffusion barriers by the oxidation of top PtRh layer and Schottky barriers formed at the grain boundaries of ITO, the variation of the carrier concentration of ITO film is minimized. Meanwhile, the life time of TFTC is more than 30 h in harsh environment. This makes ITO/PtRh:PtRh TFTC a promising candidate for precise surface temperature measurement of hot components of aeroengines.