Catalytic oxidation of lignin in solvent systems for production of renewable chemicals: A review

Lignin as the most abundant source of aromatic chemicals in nature has attracted a great deal of attention in both academia and industry. Solvolysis is one of the promising methods to convert lignin to a number of petroleum-based aromatic chemicals. The process involving the depolymerization of the lignin macromolecule and repolymerization of fragments is complicated influenced by heating methods, reaction conditions, presence of a catalyst and solvent systems. Recently, numerous investigations attempted unveiling the inherent mechanism of this process in order to promote the production of valuable aromatics. Oxidative solvolysis of lignin can produce a number of the functionalized monomeric or oligomeric chemicals. A number of research groups should be greatly appreciated with regard to their contributions on the following two concerns: (1) the cracking mechanism of inter-unit linkages during the oxidative solvolysis of lignin; and (2) the development of novel catalysts for oxidative solvolysis of lignin and their performance. Investigations on lignin oxidative solvolysis are extensively overviewed in this work, concerning the above issues and the way-forward for lignin refinery

Continental-scale niche differentiation of dominant topsoil archaea in drylands

15 págs.- 6 figuras.- 75 referenciasArchaea represent a diverse group of microorganisms often associated with extreme environments. However, an integrated understanding of biogeographical patterns of the specialist Haloarchaea and the potential generalist ammonia-oxidizing archaea (AOA) across large-scale environmental gradients remains limited. We hypothesize that niche differentiation determines their distinct distributions along environmental gradients. To test the hypothesis, we use a continental-scale research network including 173 dryland sites across northern China. Our results demonstrate that Haloarchaea and AOA dominate topsoil archaeal communities. As hypothesized, Haloarchaea and AOA show strong niche differentiation associated with two ecosystem types mainly found in China's drylands (i.e. deserts vs. grasslands), and they differ in the degree of habitat specialization. The relative abundance and richness of Haloarchaea are higher in deserts due to specialization to relatively high soil salinity and extreme climates, while those of AOA are greater in grassland soils. Our results further indicate a divergence in ecological processes underlying the segregated distributions of Haloarchaea and AOA. Haloarchaea are governed primarily by environmental-based processes while the more generalist AOA are assembled mostly via spatial-based processes. Our findings add to existing knowledge of large-scale biogeography of topsoil archaea, advancing our predictive understanding on changes in topsoil archaeal communities in a drier world.This research was supported by the National Natural Science Foundation of China (Nos. 31700463 and 31770430), National Scientific and Technological Program on Basic Resources Investigation (No. 2019FY102002), Biodiversity Survey and Assessment Project of the Ministry of Ecology and Environment, China (No. 2019HJ2096001006), the Top Leading Talents in Gansu Province to J.D. and the Innovation Base Project of Gansu Province (No. 20190323). J.C.S. was supported by the U.S. Department of Energy-BER program, as part of an Early Career Award to J.C.S. at the Pacific Northwest National Laboratory (PNNL), a multiprogram national laboratory operated by Battelle for the US Department of Energy under Contract DEAC05-76RL01830. M.D.-B. acknowledges support from the Spanish Ministry of Science and Innovation for the I +-D + i project PID2020-115813RA-I00 funded by MCIN/AEI/10.13039/501100011033. M.D.-B. is also supported by a project of the Fondo Europeo de Desarrollo Regional (FEDER) and the Consejería de Transformacion Economica, Industria, Conocimiento y Universidades of the Junta de Andalucía (FEDER Andalucía 2014–2020 Objetivo tematico ‘01 - Refuerzo de la investigacion, el desarrollo tecnologico y la innovacion’) associated with the research project P20_00879 (ANDABIOMA).Peer reviewe

Aridity-driven shift in biodiversity–soil multifunctionality relationships

From Springer Nature via Jisc Publications RouterHistory: received 2021-01-07, accepted 2021-08-12, registration 2021-08-25, pub-electronic 2021-09-09, online 2021-09-09, collection 2021-12Publication status: PublishedFunder: National Natural Science Foundation of China (National Science Foundation of China); doi: https://doi.org/10.13039/501100001809; Grant(s): 31770430Abstract: Relationships between biodiversity and multiple ecosystem functions (that is, ecosystem multifunctionality) are context-dependent. Both plant and soil microbial diversity have been reported to regulate ecosystem multifunctionality, but how their relative importance varies along environmental gradients remains poorly understood. Here, we relate plant and microbial diversity to soil multifunctionality across 130 dryland sites along a 4,000 km aridity gradient in northern China. Our results show a strong positive association between plant species richness and soil multifunctionality in less arid regions, whereas microbial diversity, in particular of fungi, is positively associated with multifunctionality in more arid regions. This shift in the relationships between plant or microbial diversity and soil multifunctionality occur at an aridity level of ∼0.8, the boundary between semiarid and arid climates, which is predicted to advance geographically ∼28% by the end of the current century. Our study highlights that biodiversity loss of plants and soil microorganisms may have especially strong consequences under low and high aridity conditions, respectively, which calls for climate-specific biodiversity conservation strategies to mitigate the effects of aridification

Rescue robot swing arm driving system and its balance control method

For limitation of the maximum permitted size and weight, a mine rescue robot(MRR) swing arm driving system was designed by taking a form of single-inverter driving dual-motor. The system model was built by use of weighted sum method, and current relationship of the dual-motor of the model was deduced and analyzed. For inconsistent MRR swing arm loads caused by complicated working conditions in coal mine underground, a balance control method for the system was proposed based on active damping mechanism. The method was tested by use of a 15 kW MRR prototype, and the result shows that the method can realize dynamic matching of torque under condition of inconsistent MRR swing arm loads

Influx-Operated Ca2+ Entry via PKD2-L1 and PKD1-L3 Channels Facilitates Sensory Responses to Polymodal Transient Stimuli

The polycystic TRP subfamily member PKD2-L1, in complex with PKD1-L3, is involved in physiological responses to diverse stimuli. A major challenge to understanding whether and how PKD2-L1/PKD1-L3 acts as a bona fide molecular transducer is that recombinant channels usually respond with small or undetectable currents. Here, we discover a type of Ca2+ influx-operated Ca2+ entry (ICE) that generates pronounced Ca2+ spikes. Triggered by rapid onset/offset of Ca2+, voltage, or acid stimuli, Ca2+-dependent activation amplifies a small Ca2+ influx via the channel. Ca2+ concurrently drives a self-limiting negative feedback (Ca2+-dependent inactivation) that is regulated by the Ca2+-binding EF hands of PKD2-L1. Our results suggest a biphasic ICE with opposite Ca2+ feedback regulation that facilitates sensory responses to multimodal transient stimuli. We suggest that such a mechanism may also occur for other sensory modalities and other Ca2+ channels

Possible intrauterine SARS-CoV-2 infection: Positive nucleic acid testing results and consecutive positive SARS-CoV-2-specific antibody levels within 50 days after birth

Whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) affects the fetus in utero is important to the well-being of the mother and neonate. We report the case of a full-term neonate born to a mother who developed symptoms of coronavirus disease 2019 (COVID-19) at 32 weeks of gestation. The placental pathology showed slight local inflammation. Serial quantitative antibody measurements in the neonate showed elevated levels of IgM on the day of birth and a gradual decline to negative levels within 28 days of life; the levels of IgG declined gradually, but IgG was still positive on day 50 of life. The sequential dynamic changes in antibody levels in the neonate were consistent with those in his mother. One-step reverse transcriptase droplet digital PCR testing for SARS-CoV-2 nucleic acid in throat and anal swabs showed positive results (750 and 892 copies/ml) on day 7 of life and negative results on day 14 of life. The neonate had no symptoms of COVID-19. This report enables us to re-evaluate the significance of IgM detection in intrauterine SARS-CoV-2 infection and presents a favorable prognosis for the neonate with long-term exposure to maternal COVID-19, despite a high possibility of intrauterine infection

NrtNet: An Unsupervised Method for 3D Non-Rigid Point Cloud Registration Based on Transformer

Self-attention networks have revolutionized the field of natural language processing and have also made impressive progress in image analysis tasks. Corrnet3D proposes the idea of first obtaining the point cloud correspondence in point cloud registration. Inspired by these successes, we propose an unsupervised network for non-rigid point cloud registration, namely NrtNet, which is the first network using a transformer for unsupervised large deformation non-rigid point cloud registration. Specifically, NrtNet consists of a feature extraction module, a correspondence matrix generation module, and a reconstruction module. Feeding a pair of point clouds, our model first learns the point-by-point features and feeds them to the transformer-based correspondence matrix generation module, which utilizes the transformer to learn the correspondence probability between pairs of point sets, and then the correspondence probability matrix conducts normalization to obtain the correct point set corresponding matrix. We then permute the point clouds and learn the relative drift of the point pairs to reconstruct the point clouds for registration. Extensive experiments on synthetic and real datasets of non-rigid 3D shapes show that NrtNet outperforms state-of-the-art methods, including methods that use grids as input and methods that directly compute point drift

A Complexity Analysis Approach for Model-based System Engineering

With the increasing complexity of the highly engineered products, Model-based Systems Engineering (MBSE) is proposed to support the complexity management of the product development. As the basic of complexity management, complexity analysis is used to measure the system complexity for system solution trade-offs. Using traditional MBSE approaches, system architectures of product are formalized as MBSE models whose complexity measurement provides cues to quantitative trade-offs. In this paper, an MBSE approach is proposed to support complex analysis using qualitative and quantitative approaches. A GOPPRR approach is first proposed to support MBSE formalisms. Then a complexity measurement formula is used to calculate the structure complexity of the MBSE models. Finally, through a tool-chain developed based on Open Services for Lifecycle Collaboration (OSLC), a visualization tool is used to analyze the system complexity by measuring and visualizing the model complexity. A case study is proposed to evaluate the potentials of this approach for supporting product trade-offs. From the results, the approach enables to calculate complexity of MBSE models and virtualizes the model topologies