The history of the South China Craton and the constituent Yangtze and Cathaysia blocks are directly linked to Earth's Phanerozoic and Precambrian record of supercontinent assembly and dispersal. ...Exposed Archean rocks are limited to isolated fragments in the Yangtze Block that preserve a record of Meso- to Neo-Archean magmatism, sedimentation and metamorphism associated with a period of global craton formation and stabilization that corresponds with the assembly of the Kenor supercontinent/supercraton. However, there are insufficient data to link its history with other similar aged cratons. The tectonostratigraphic record in South China in the Paleoproterozoic, corresponding with the assembly of Nuna, suggests that rock units in the Yangtze Block were spatially linked with northwestern Laurentia and possibly Siberia, whereas Cathaysia was joined to northern India. During the formation of Rodinia at the end of the Mesoproterozoic through to that of Pangea in the mid-Paleozoic, Cathaysia remained joined to northern India. Early Neoproterozoic supra-subduction zone magmatic arc-back arc assemblages ranging in age from ~1000Ma to 810Ma occur within Cathaysia, along its northwestern margin, and along the southeastern margin of the Yangtze Block. These rocks provide a record of convergent plate interaction, which continued along the western margin of the Yangtze Block until around 700Ma and correlates with similar along strike subduction zone magmatism in northwest India, Seychelles and Madagascar. During the final assembly of Gondwana in the early Paleozoic suturing of India-South China with the Western Australia-Mawson blocks along the Kuunga Orogen resulted in the accretion of the Sanya Block of Hainan Island with the rest of Cathaysia. The accretion of Laurussia to Gondwana in the mid-Paleozoic to form Pangea corresponds with the initiation of lithospheric extension along the northern margin of Gondwana and the separation of a number of continental blocks, including South China, which then drifted northward across the Paleo-Tethys to collide with the Asian segment of Pangea in the Permo-Triassic.
Poly(N‐vinylpyrrolidone) (PVP), an important water soluble synthetic polymer, has many desirable properties including low toxicity, chemical stability, and good biocompatibility. Since PVP is ...hemocompatible and physiologically inactive, it has been used as a blood plasma substitute. Surface modification with PVP has been investigated extensively over the past few years as a means of preventing nonspecific protein adsorption. PVP may therefore be seen as a promising antifouling surface modifier comparable to poly(ethylene glycol) (PEG). In this review, various approaches for the design and preparation of PVP‐modified surfaces are summarized and potential biomedical applications of these PVP‐modified materials are indicated. Finally, some perspectives on future research on PVP for surface modification are discussed.
In this review, a brief introduction to surface modification using poly(N‐vinylpyrrolidone) and its copolymers and their potential biomedical applications is presented. Some perspectives on future research in the areas are also discussed.
The first 1000 days of life are a critical window period for rapid growth and development during which individuals are more sensitive to the stimulation of environmental factors ....
The Cambrian–Ordovician boundary unconformity in the southern part of the South China Craton is spatially and temporally related to coeval orogenic activity along the Indian margin of east Gondwana. ...Detrital zircon age spectra from strata above and below the unconformity range in age from 3580–450Ma, with peaks in the late Mesoproterozoic and Neoproterozoic. The patterns are similar to time equivalent sequences elsewhere in South China and together with regional facies relationships and paleocurrent data indicate derivation from a Gondwana source. The disconformity at the base of the Ordovician succession forms part of a regional break that has also been documented in the Himalaya, Qiangtang, Lhasa, Sibumasu, and Western Australia. All these successions have similar detrital zircon age spectra suggesting derivation from common source(s). In South China the effects of this tectonic event are relatively mild and are represented by a local disconformity at the base of the Ordovician succession, but elsewhere in north Gondwana this event is marked by an angular unconformity with metamorphism of older units and relatively widespread magmatic activity. South China was likely located in a distal location to the northeast of the pulse of tectonic activity, which was focused in the Himalaya region, and was close to the continent–ocean boundary between northern Gondwana and the proto-Tethys.
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•South China was located along the northernmost margin of East Gondwana.•Early Paleozoic orogenic activity in north Gondwana affected South China.•Detritus from the Himalayan region accumulated in South China.•South China represents the distal portion of the northward facing synorogenic basin.
•A late Cryogenian and an Ediacaran climate cooling events recognized within siliciclastic strata overlying the Cathaysia Block, South China, and likely coincide with the global Marinoan and Gaskiers ...glaciations.•Cryogenian siliciclastic rocks overlying the Jiangnan Orogen were derived from local sources within South China.•Late Crogenian and Ediacaran siliciclastic rocks derived from sources external to the craton.•South China Craton linked to northern India since the Cryogenian.
Neoproterozoic paleogeography of the South China is dominated by the formation of Rodinia, its break-up, and the subsequent amalgamation of Gondwana. Two negative excursions of the chemical index of alteration (CIA) and the chemical index of weathering (CIW) recorded in the Cryogenian to Ediacaran sedimentary rocks of the Cathaysia Block, South China, indicate two cooling events. In combination with available age constraints, this data suggests correlation with the global Marinoan (ca. 650–635 Ma) and Gaskiers (ca. 579 Ma) glaciations. U-Pb ages of detrital zircons from the Cryogenian to lower Ediacaran strata define two distinctive age peaks at 1056 Ma and 998 Ma, whereas the upper Ediacaran strata show only one age peak at 957 Ma. These data demonstrate Neoproterozoic sedimentary rocks in the Cathaysia Block were derived from a source external to the craton. The predominant late Mesoproterozoic to early Neoproterozoic (1140–870 Ma) detrital zircons were most likely derived from a source dominated by North India and East Antarctica with limited input from Western Australia. Furthermore, εHf(t) values of detrital zircons are similar to the coeval detrital zircons from Rayner-Eastern Ghats. The detrital record of the late Cryogenian and Ediacaran strata in the Cathaysia Block suggests that the South China Block was connected to the northern margin of India during the dispersal of Rodinia and the assembly of East Gondwana. Detrital zircons from Cryogenian strata overlying the Jiangnan Orogen are largely in the range 900–700 Ma with scattered Archean and Paleoproterozoic grains. These ages are consistent with derivation from local sources within South China. The timing of accumulation of these units, after collisional assembly of South China, likely accounts for their more restricted provenance with collision generated relief providing both a local source and restricting input from further south within India and/or the rest of Gondwana.
Cambrian sedimentary rocks in the southern part of the South China Craton were derived from a source that lay to the south or southeast, beyond the current limits of the craton and which is no longer ...preserved nearby. U‐Pb ages and Hf isotope data on detrital zircons from the Cambrian sequence define two distinctive age peaks at 1120 Ma and 960 Ma, with εHf(t) values for each group identical to the coeval detrital zircons from Western Australia and the Tethyan Himalaya zone, respectively. The circa 1120 Ma detrital zircons were most likely derived from the Wilkes‐Albany‐Fraser belt between southwest Australia and Antarctica, whereas the circa 960 Ma detrital zircons could have been sourced from the Rayner‐Eastern Ghats belt between India and Antarctica. Derivation of detritus from these sources suggests that south China was located at the nexus between India, Antarctica, and Australia, along the northern margin of East Gondwana during the Cambrian.
Key Points
Cambrian sandstones in south China were derived from an exotic source
Source is the Wilkes‐Albany‐Fraser and Rayner‐E Ghats belts in East Gondwana
South China was located at the nexus between India, Antarctica, and Australia
Epidemiological studies show that maternal exposure to PM2.5 affects the neurodevelopment of the offspring, especially the neurocognitive function. However, no relevant experimental researches have ...been published on toxic mechanism and diet intervention. We evaluated the effects of exposure to different doses of PM2.5 on the behavioral development of offspring via a PM2.5 exposure model established by intratracheal instillation, explored its mechanism and the protective effects of quercetin and VC intervention, and focused on the protein expression of CREB/BDNF signaling pathway. Specifically, Exposure to PM2.5 during gestation and lactation period caused maternal oxidative stress. Maternal exposure to PM2.5 changed postnatal open-field behaviors in both gender, impaired spatial learning and memory in the female offspring, increased the level of IL-1β, IL-6, down-regulated p-CREB/CREB, BDNF, TrkB, p-CaMKII/CaMKII, p-CaMKIV/CaMKIV, up-regulated p-Akt/Akt and p-ERK1/2/ERK1/2 in the offspring. In addition, maternal supplementation with quercetin ameliorate the maternal oxidative stress, improved progeny inflammatory response, regulated BDNF, TrkB, p-Akt/Akt, p-ERK1/2/ERK1/2 in female offspring, regulated TrkB, p-CREB/CREB and p-Akt/Akt in male offspring. Maternal supplementation with VC increased the levels of CAT in maternal mice, up-regulated BDNF in female offspring, regulated p-CREB/CREB and p-ERK1/2/ERK1/2 in male offspring. Our findings indicate that PM2.5 exposure during pregnancy and lactation could impair behavioral development of offspring. Quercetin shows more protective effects than VC. The mechanism of neurodevelopmental toxicity induced by PM2.5 may be related to oxidative stress, inflammatory response and modulation of the CREB/BDNF signaling pathway.
•PM2.5 exposure caused maternal oxidative stress.•PM2.5 changed postnatal open-field behaviors in both gender and impaired spatial learning and memory in the female.•PM2.5 increased the level of IL-1β, IL-6, down-regulated p-CREB/CREB, BDNF, TrkB, p-CaMKII/CaMKII, p-CaMKIV/CaMKIV, upregulated p-Akt/Akt and p-ERK1/2/ERK1/2 in the offspring.•Quercetin and VC showed some protective effects.
Counterfactual thinking is presumed to play a preparatory function in promoting people’s behavioural intentions. This study specifically addresses the impacts of COVID-19 severity, tourists’ ...counterfactual thinking about the pandemic, and tourists’ perceived duty-free consumption value on the effect of a duty-free policy on travel intentions. Four hundred and ten participants took part in this study, which involved a 2 (duty-free policy: absent vs. present) × 2 (COVID-19 severity: high vs. low) design. Results reveal the following patterns: (a) compared to the absence of a duty-free policy in tourist destinations, enactment of a duty-free policy leads to stronger visit intentions through greater perceived value and (b) the effect of a duty-free policy on travel intention is moderated by tourists’ counterfactual thinking and COVID-19 severity.
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