Bioactive species, including reactive oxygen species (ROS, including O
2
&z.rad;
−
, H
2
O
2
, HOCl,
1
O
2
, &z.rad;OH, HOBr,
etc.
), reactive nitrogen species (RNS, including ONOO
−
, NO, NO
2
, ...HNO,
etc.
), reactive sulfur species (RSS, including GSH, Hcy, Cys, H
2
S, H
2
S
n
, SO
2
derivatives,
etc.
), ATP, HCHO, CO and so on, are a highly important category of molecules in living cells. The dynamic fluctuations of these molecules in subcellular microenvironments determine cellular homeostasis, signal conduction, immunity and metabolism. However, their abnormal expressions can cause disorders which are associated with diverse major diseases. Monitoring bioactive molecules in subcellular structures is therefore critical for bioanalysis and related drug discovery. With the emergence of organelle-targeted fluorescent probes, significant progress has been made in subcellular imaging. Among the developed subcellular localization fluorescent tools, ROS, RNS and RSS (RONSS) probes are highly attractive, owing to their potential for revealing the physiological and pathological functions of these highly reactive, interactive and interconvertible molecules during diverse biological events, which are rather significant for advancing our understanding of different life phenomena and exploring new technologies for life regulation. This review mainly illustrates the design principles, detection mechanisms, current challenges, and potential future directions of organelle-targeted fluorescent probes toward RONSS.
The dynamic fluctuations of bioactive species in living cells are associated with numerous physiological and pathological phenomena. The emergence of organelle-targeted fluorescent probes has significantly facilitated our understanding on the biological functions of these species. This review describes the design, applications, challenges and potential directions of organelle-targeted bioactive species probes.
•We investigate impacts of climate variability and human activity on annual flow in the midstream of the Yellow River.•Annual streamflow shows significant decreases from 0.10mm/yr to 1.61mm/yr at ...most stations.•Decreasing precipitation and increasing temperature are detected for the whole study area.•Climate variability has a greater effect on the streamflow decrease in the Beiluo and Yan Rivers.•Human activities accounted for more of the streamflow reduction in the majority of tributaries.
The middle reaches of the Yellow River basin (MRYRB) contribute significantly to the total streamflow and sediment discharge of the Yellow River. Significant changes in streamflow have been detected; these changes result in part from large number of soil and water conservation measures implemented over the past six decades in this area. This study investigates streamflow variations and evaluates the impacts of climate variability and human activity on the mean annual flow in the MRYRB. The non-parametric Mann–Kendall test and Pettitt’s test are applied to characterize the trends and abrupt changes of hydro-climatic variables in the MRYRB. The analysis was performed on streamflow data taken over the period from the 1950s to 2010 at 18 hydrological stations and on precipitation, temperature and potential evapotranspiration (PET) data from 43 climate stations. We find that 16 of these stations recorded significant decreases in annual streamflow, with reduction rates ranging from 0.10mm/yr to 1.61mm/yr over the study period. Precipitation at all of the stations also had negative trends, with changes ranging from −4.7mm/yr to −0.19mm/yr. Temperature increased significantly at most stations, while PET showed a mixed of upward and downward trend. Abrupt changes in streamflow at mainstream stations occurred when large reservoirs were built, while breakpoints of streamflow at tributary stations were mainly driven by the implementation of soil and water conservation measures. We used both Budyko’s curve (a simple water balance model) and linear regression to evaluate the potential impacts of climate variability and human activities on mean annual streamflow. Climate variability has a greater effect on the streamflow reduction in the Beiluo River and Yan River, while human activities accounted for more of the streamflow changes in other tributaries, especially in the northern catchments. In general, human activities, including soil and water conservation projects, the operation of dams and reservoirs, and water consumption, are found to be the dominant factors responsible for the significant decline in the annual streamflow in the MRYRB over the last six decades.
Excessive use of agro-chemicals （such as mineral fertilizers） poses potential risks to soil quality. Application of organic amendments and reduction of inorganic fertilizer are economically feasible ...and environmentally sound approaches to de- velop sustainable agriculture. This study investigated and evaluated the effects of mineral fertilizer reduction and partial substitution of organic amendment on soil fertility and heavy metal content in a 10-season continually planted vegetable field during 2009-2012. The experiment included four treatments： 100% chemical fertilizer （CF100）, 80% chemical fertilizer （CF80）, 60% chemical fertilizer and 20% organic fertilizer （CF60＋OM20）, and 40% chemical fertilizer and 40% organic fertilizer （CF40＋OM40）. Soil nutrients, enzyme activity and heavy metal content were determined. The results showed that single chemical fertilizer reduction （CF80） had no significant effect on soil organic matter content, soil catalase activity and soil heavy metal content, but slightly reduced soil available N, P, K, and soil urease activity, and significantly reduced soil acid phosphatase activity. Compared with CF100, 40 or 60% reduction of chemical fertilizer supplemented with organic fertilizer （CF60＋OM20, CF40＋OM40） significantly increased soil organic matter, soil catalase activity and urease activity especially in last several seasons, but reduced soil available P, K, and soil acid phosphatase activity. In addition, continu- ous application of organic fertilizer resulted in higher accumulation of Zn, Cd, and Cr in soil in the late stage of experiment, which may induce adverse effects on soil health and food safety.
Oxide perovskite materials have a long history of being investigated for thermoelectric applications. Compared to the state-of-the-art tin and lead chalcogenides, these perovskite compounds have ...advantages of low toxicity, eco-friendliness, and high elemental abundance. However, because of low electrical conductivity and high thermal conductivity, the total thermoelectric performance of oxide perovskites is relatively poor. Variety of methods were used to enhance the TE properties of oxide perovskite materials, such as doping, inducing oxygen vacancy, embedding crystal imperfection, and so on. Recently, hybrid perovskite materials started to draw attention for thermoelectric application. Due to the low thermal conductivity and high Seebeck coefficient feature of hybrid perovskites materials, they can be promising thermoelectric materials and hold the potential for the application of wearable energy generators and cooling devices. This mini-review will build a bridge between oxide perovskites and burgeoning hybrid halide perovskites in the research of thermoelectric properties with an aim to further enhance the relevant performance of perovskite-type materials.
Granite petrogenesis is associated with the formation and evolution of continental crust along convergent plate boundaries. While magmatic processes such as partial melting and fractional ...crystallization result in the compositional diversity of granites, the nature of magma sources is related to tectonic settings of granite generation. Although granites consist predominantly of magmatic minerals, they generally contain small amounts of peritectic and residual minerals. This results in the compositional difference between natural granites and experimental melts. In addition to the fractional crystallization of mantle-derived mafic magmas for the generation of granites during accretionary orogeny, a wide range of crustal rocks can be partially melted to form granites in both accretionary and collisional orogens. In the latter case, metasedimentary and metaigneous crustal sources lead to the dichotomy of S- and I-type granites. Geochemically, granites with negative εNd(t) and εHf(t) values are certainly derived from reworking of the ancient crust. On the other hand, granites with positive εNd(t) and εHf(t) values may be produced either by reworking of the juvenile crust or by fractional crystallization of asthenospheric mantle-derived magmas at actively convergent plate boundaries. In this case, major and trace elements may be of use in distinguishing between the crustal and mantle contributions. Granite, migmatite and granulite generally form lithological associations at previously converged plate boundaries, with migmatitic domes as the major component of metamorphic core complexes. Their formation is related to extensional heating subsequent to thinning of the thickened mantle lithosphere. As soon as the thickened lithospheric mantle was foundered into the asthenospheric mantle, it makes the space for asthenospheric upwelling to induce active rifting along the thinned lithosphere. This provides an external heat source for anatectic metamorphism at high thermal gradients, marking the tectonic transition in the property of orogenic systems into the rifting stage. Therefore, the active rifting is spatially and temporally dictated by thinning of the orogenic mantle lithosphere, and its operation is a geodynamic mechanism for crustal anatexis at convergent plate boundaries. Consequently, the lithospheric thickness has a profound effect on crustal anatexis for granitic magmatism, which is considerably later than plate convergence.
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•Partial melting of crustal rocks produces granitic magmas with varying compositions.•Both ancient and juvenile crust underwent partial melting to produce granitic magmas.•Active rifting is a geodynamic mechanism of crustal anatexis in fossil suture zone.•Rifting orogeny is realized by domical uplift of granites and metamorphic core complexes.•The lithospheric thickness has a profound effect on crustal anatexis for granitic magmatism.
Bacteria, as the key component of soil ecosystems, participate in nutrient cycling and organic matter decomposition. However, how fertilization regime affects the rhizospheric bacterial community of ...reddish paddy soil remains unclear. Here, a long-term fertilization experiment initiated in 1982 was employed to explore the impacts of different fertilization regimes on physicochemical properties and bacterial communities of reddish paddy rhizospheric soil in Central South China by sequencing the 16S rRNA gene. The results showed that long-term fertilization improved the soil nutrient status and shaped the distinct rhizospheric bacterial communities. Particularly, chemical NPK fertilizers application significantly declined the richness of the bacterial community by 7.32%, whereas the application of manure alone or combined with chemical NPK fertilizers significantly increased the biodiversity of the bacterial community by 1.45%, 1.87% compared with no fertilization, respectively. Moreover, LEfSe indicated that application of chemical NPK fertilizers significantly enhanced the abundances of Verrucomicrobia and Nitrospiraceae, while manure significantly increased the abundances of Deltaproteobacteria and Myxococcales, but the most abundant Actinobacteria and Planctomycetes were detected in the treatment that combined application of manure and chemical NPK fertilizers. Furthermore, canonical correspondence analysis (CCA) and the Mantel test clarified that exchangeable Mg
(E-Mg
), soil organic carbon (SOC) and alkali-hydrolyzable nitrogen (AN) are the key driving factors for shaping bacterial communities in the rhizosphere. Our results suggested that long-term balanced using of manure and chemical fertilizers not only increased organic material pools and nutrient availability but also enhanced the biodiversity of the rhizospheric bacterial community and the abundance of Actinobacteria, which contribute to the sustainable development of agro-ecosystems.
While the studies on the material interaction with mesenchymal stem cells (MSCs) have been mainly focused on the ability of materials to provide environment to regulate cell viability, proliferation ...or differentiation, the therapeutic effects of MSC-material constructs may result from the secretion of immunomodulatory and angiogenic cytokines from MSCs. Here, electrospun scaffolds composed of fibers in random, aligned and mesh-like patterns were fabricated, and the paracrine behavior of adipose-derived MSCs (Ad-MSCs) on the scaffolds were investigated in comparison to the cell culture via conventional microplates. It was found that the Ad-MSCs on the electrospun fibers produced significantly higher levels of anti-inflammatory and pro-angiogenic cytokines compared to those cultured on microplates. The enhanced modulatory effects of the secreted products of Ad-MSCs on fibrous electrospun scaffolds were also proven in the cultures of endothelial cells and the LPS-stimulated macrophages, with three types of scaffolds showing distinct influences on the paracrine function of Ad-MSCs. In a skin excisional wound-healing model in rat, the conditioned medium collected from the MSC-scaffold system accelerated the wound closure, promoted the macrophage recruitment and enhanced the polarization of macrophages toward the pro-healing phenotype in the wound bed. Our study demonstrates that the fibrous topography of scaffolds is a key material property that modulates the paracrine function of cells. The discovery elucidates a new aspect of material functions, laying the foundation for developing scaffold materials to promote tissue regeneration/repair through guiding the paracrine signaling network.
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In this study, a novel Co3O4/Co(OH)2 heterostructure is obtained via electrodeposition on nickel (Ni) foam, forming sandwich‐like structure and freestanding electrode. The outer Co(OH)2 with layered ...structure can provide sufficient absorption sites and enable facile ion intercalation, meanwhile the presence of a conductive and robust interfacial Co3O4 layer between Ni foam and Co(OH)2 is found effectively minimizes the charge transfer resistance and stabilizes the interface, thus improving the electrode's rate and cycling performance with high capacity preserved synergistically. Furthermore, the structural evolution of Co(OH)2 and Co3O4 upon cycling are elucidated systematically using a series of in situ and ex situ techniques. The Co(OH)2 is found irreversibly changed to CoOOH upon first charge, which is then reversibly converted to CoO2 during the subsequent charge–discharge cycles. The Co3O4 exhibits negligible phase changes of the bulk upon cycling, indicating its good structural integrity that contributes to the significantly improved cyclability. In general, this work not only offers an ease and effective approach to optimize the charge storage properties of Co3O4/Co(OH)2 heterostructure via interfacial layer control, but also provides valuable insights in understanding their charge storage mechanisms, which may inspire the development of more heterostructures or extend to other applications.
Interfacial layer control of freestanding sandwich‐like Co3O4/Co(OH)2 heterostructure is reported as a generalized and effective approach to optimize the electrode's charge storage properties, leading to improved rate and cycle performance. This work also provides valuable insights in understanding the charge storage mechanisms of Co3O4 and Co(OH)2, which will promote the rational design of more heterostructures with excellent electrochemical performance.
In this work, a microwave welding method has been used for the construction of chemical Ni–C bonding at the interface between carbon nanotubes (CNTs) and metal Ni to provide a different surface ...electron distribution, which determined the electromagnetic (EM) wave absorption properties based on a surface plasmon resonance mechanism. Through a serial of detailed examinations, such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and Raman spectrum, the as-expected chemical Ni–C bonding between CNTs and metal Ni has been confirmed. And the Brunauer–Emmett–Teller and surface zeta potential measurements uncovered the great evolution of structure and electronic density compared with CNTs, metal Ni, and Ni–CNT composite without Ni–C bonding. Correspondingly, except the EM absorption due to CNTs and metal Ni in the composite, another wide and strong EM absorption band ranging from 10 to 18 GHz was found, which was induced by the Ni–C bonded interface. With a thinner thickness and more exposed Ni–C interfaces, the Ni–CNT composite displayed less reflection loss.
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