Up to now, conjugated organic polymers as organic semiconductors have received more and more attention on the direct conversion of water to hydrogen energy. Herein, we designed and synthesized a series of porphyrin-based conjugated polymers (Zn-ZnDETPP, Co-CoDETPP, and Zn-CoDETPP) with intrinsic semiconducting feature and broad spectral response ability. The Zn-CoDETPP polymer exhibits a photocatalytic H 2 generation activity (43 μmol h −1 ) illuminated by λ ≥ 400 nm light and a record apparent quantum yield (7.36%) at λ = 400 nm monochromatic light among those porphyrin-based polymers reported previously, while the Zn-ZnDETPP and Co-CoDETPP only deliver a H 2 generation activity of 8.0 and 33 μmol h −1 respectively. The characteristic results demonstrate that the CoDETPP porphyrin units as bridges in the Zn-CoDETPP polymer can act as an electron acceptor and promote the metal-to-metal charge transfer (MMCT) from zinc porphyrin to cobalt porphyrin units, which could lead to more effective and faster charge separation in the Zn-CoDETPP polymer for the H 2 generation reaction. The present results open up a promising strategy applying porphyrin-based conjugated polymers as intrinsic semiconductors for efficient H 2 generation and instruct us to efficiently convert solar energy into chemical energy by molecular designing.

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The ultrasonic communication in Concave-eared torrent frogs Odorrana tormota is believed to be an adaptation to avoid masking by the intense low-frequency noise of the rushing stream in their habitat. The acoustic adaptation hypothesis for ultrasonic origin predicts that some organisms subjecting to persistent acoustic interference from broadband, low-frequency environmental noise, might shift their signal frequency upward into frequency bands with lower noise energy. In other words, low-frequency environmental noise might cause upward shifts of species’ vocalization frequencies making their signals more conspicuous. Presently, it is unclear whether male O. tormota adjust their signal features in response to a change in the ambient noise level. We tested the prediction of the acoustic adaptation hypothesis by recording the vocalizations of male O. tormota inhabiting two streams with different background noise levels in Huangshan in central China and comparing their call features including the fundamental frequency (F0). Results showed that the spectrotemporal characteristics of the vocal signals of males in the two habitats were indifferent, except the duration of the call harmonic segments and three parameters related to the call fundamental frequency (F0). In terms of the F0, the pooled and individual frog data showed that frogs inhabiting the noisier habitat tended to emit calls having higher F0. The higher F0 increases the signal-to-noise ratio, thus benefiting the detection of vocalization. Thus, similar to several anuran species, concave-eared torrent frogs also display noise-dependent adjustment of vocal pitch in their vocalizations for making them more audible.

BackgroundHyperinflammation and coagulopathy are hallmarks of COVID-19 and synergistically contribute to illness progression. Antiplatelet agents have been proposed as candidate drugs for COVID-19 treatment on the basis of their antithrombotic and anti-inflammatory properties. A systematic review and meta-analysis that included early observational studies and recent randomized controlled trials (RCTs) was performed to summarize and compare evidence on this issue.MethodsPubMed, Embase, and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched to identify studies published up to Nov 7, 2021, and the results of registered clinical trials were followed up to Mar 30, 2022. We included RCTs and observational studies assessing the effect of antiplatelet therapy in adult patients with COVID-19. Data on baseline patient characteristics, interventions, controls, and outcomes were extracted by two independent reviewers. The primary outcome was mortality. Data were pooled using a random-effects model.ResultsTwenty-seven studies were included, of which 23 observational studies were pooled in a meta-analysis, and the remaining four RCTs (ACTIV-4B, RECOVERY, ACTIV-4a, and REMAP-CAP) were narratively synthesized. Based on 23 observational studies of 87,824 COVID-19 patients, antiplatelet treatment favors a lower risk of mortality [odds ratio (OR) 0.72, 95% confidence interval (CI) 0.61–0.85; I2 = 87.0%, P < 0.01]. The narrative synthesis of RCTs showed conflicting evidence, which did not support adding antiplatelet therapy to the standard care, regardless of the baseline illness severity and concomitant anticoagulation intensity.ConclusionWhile the rationale for using antiplatelet treatment in COVID-19 patients is compelling and was supported by the combined result of early observational studies, evidence from RCTs did not confirm this approach. Several factors that could explain this inconsistency were highlighted alongside perspectives on future research directions.