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It is challenging to achieve high selectivity over Pt-metal-oxide catalysts widely used in many selective oxidation reactions because Pt is prone to over-oxidize substrates. Herein, our sound strategy for enhancing the selectivity is to saturate the under-coordinated single Pt atoms with Cl- ligands. In this system, the weak electronic metal-support interactions between Pt atoms and reduced TiO2 cause electron extraction from Pt to Cl- ligands, resulting in strong Pt-Cl bonds. Therefore, the two-coordinate single Pt atoms adopt a four-coordinate configuration and thus inactivated, thereby inhibiting the over-oxidation of toluene over Pt sites. The selectivity for the primary C-H bond oxidation products of toluene was increased from 50.1 to 100%. Meanwhile, the abundant active Ti3+ sites were stabilized in reduced TiO2 by Pt atoms, leading to a rising yield of the primary C-H oxidation products of 249.8 mmol gcat-1. The reported strategy holds great promise for selective oxidation with enhanced selectivity.
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Purpose: Depression disorder is the most commonly diagnosed type of mental illness among youths. Although a plethora of evidence suggests a positive relationship between exercise and lower levels of depression in youths, the findings regarding the variation in magnitude of this relationship are inconclusive with respect to the preventive and therapeutic effects of different types of exercise. This network meta-analysis aimed to determine the best type of exercise for the treatment and prevention of depression in youths. Methods: A comprehensive search of databases, including PubMed, EMBASE, The Cochrane Library, Web of Science, PsychINFO, ProQuest, Wanfang, and CNKI, was conducted to identify relevant research on exercise interventions for depression in youth populations. The risk of bias in the included studies was evaluated using Cochrane Review Manager 5.4 according to the Cochrane Handbook 5.1.0 Methodological Quality Evaluation Criteria. The network meta-analysis was performed using STATA 15.1 to calculate the standardized mean difference (SMD) of all concerned outcomes. The node-splitting method was used to test the local inconsistency of the network meta-analysis. Funnel plots were used to evaluate the potential impact of bias in this study. Result: Utilizing data extracted from 58 studies (10 countries, 4,887 participants), we found that for depressed youths, exercise is significantly better than usual care in reducing anxiety (SMD = -0.98, 95% CI [-1.50, -0.45]). For non-depressed youths, exercise is significantly better than usual care in reducing anxiety (SMD = -0.47, 95% CI [ -0.66, -0.29]). In the treatment of depression, resistance exercise (SMD = -1.30, 95% CI [ -1.96, -0.64]), aerobic exercise (SMD = -0.83, 95% CI [-1.10 -0.72]), mixed exercise (SMD = -0.67, 95% CI [-0.99, -0.35]), and mind-body exercise (SMD = -0.61, 95% CI [-0.84, -0.38]) all showed significant efficacy over usual care. For the prevention of depression, resistance exercise (SMD = -1.18, 95% CI [-1.65, -0.71]), aerobic exercise (SMD = -0.72, 95% CI [-0.98, -0.47]), mind-body exercise (SMD = -0.59, 95% CI [-0.93, -0.26]), and mixed exercise (SMD = -1.06, 95% CI [-1.37 to -0.75]) were all significantly effective compared to usual care. According to the test of the surface under the cumulative ranking score (SUCRA), the ranking of exercises for the treatment of depression in depressed youths is as follows: resistance exercise (94.9%) > aerobic exercise (75.1%) > mixed exercise (43.8%) > mind-body exercise (36.2%) > usual care (0%). For the prevention of depression in non-depressed youths, resistance exercise (90.3%) > mixed exercise (81.6%) > aerobic exercise (45.5%) > mind-body exercise (32.6%) > usual care (0%). Resistance exercise thus had the best comprehensive effect on both the treatment and prevention of depression in youths (clusterank value = 1914.04). Subgroup analyses show that a frequency of 3-4 times per week, a duration of 30-60 min, and a length of more than 6 weeks were found to be the most effective interventions for depression (P > 0.001). Conclusion: This study provides compelling evidence that exercise is a viable intervention for improving depression and anxiety in young individuals. In addition, the study emphasizes the importance of selecting the appropriate type of exercise to optimize treatment and prevention. Specifically, the results suggest that resistance exercise, performed 3-4 times per week, with sessions lasting 30-60 min and a length of more than 6 weeks, yields optimal results for the treatment and prevention of depression in young individuals. These findings have significant implications for clinical practice, particularly given the challenges associated with implementing effective interventions and the economic burden of treating and preventing depression in young people. However, it is worth noting that additional head-to-head studies are necessary to confirm these findings and strengthen the evidence base. Nevertheless, this study provides valuable insights into the role of exercise as a potential treatment and preventative measure for depression in young people. Systematic review registration: https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=374154, identifier: 374154.
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We report a broadband electron paramagnetic resonance (EPR) spectrometer that operates continuously in the frequency range from 1 to 15 GHz. A broadband metallic coplanar waveguide is utilized as the probe. The system is capable of performing EPR measurements in both continuous wave and pulsed modes. Its performance has been tested with a sample, named 2,2-diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl powder, at room temperature. In the continuous wave mode, the sensitivity of the spectrometer is estimated to be 3.3×1012 spins/gaussHz at 13 GHz. In the pulsed mode, inversion recovery experiments were carried out to obtain the spin-lattice relaxation time of the sample.
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We report an X-band pulsed electron paramagnetic resonance (EPR) spectrometer using a Field-Programmable-Gate-Array (FPGA) based pulse generator. The microwave (MW) pulse length and pulse-pulse interval can be adjusted with 50 ps time resolution. A FPGA based pulse generator is utilized to achieve such time resolution. There are eight pulse channels integrated in the pulse generator. Each channel outputs rectangular pulses with 50 ps time resolution. The spectrometer includes a pulse forming unit, where four high-speed PIN diode switches are controlled by the pulse generator to generate MW pulses. A commercial digital storage oscilloscope is used to record the EPR signal. A customized software is developed to control the components of the spectrometer and to perform data processing task. The usefulness of high time resolution is demonstrated by the results of Rabi oscillation.
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We report on coplanar waveguides (CPWs) designed for optically detected magnetic resonance of nitrogen-vacancy (NV) centers in diamonds. A broad band up to 15.8 GHz has been realized, which ensures that the electron spins can be manipulated under external magnetic fields up to 5000 G. The conversion factor of CPW has been measured by Rabi nutation experiments, which ranges from 6.64 G W-1/2 to 10.60 G W-1/2 in the frequency band from 0.76 GHz to 17.3 GHz. Broadband CPWs also provide high quality control pulses due to the minimization of the distortion. These characteristics will find potential applications in NV-based quantum information processing and single spin magnetometry.