Search

The Silurian–Devonian transition experienced dramatic changes of climates, global carbon cycles and faunas, but detailed documentation of the environments and biotas during this transitional interval in the South China Block is needed. The upper Silurian–Lower Devonian sequence of Qujing, Yunnan, southwestern China, represents one of the rare stratigraphic records of this transition in the South China Block. In this study, the Xiaxishancun Formation of Qujing, a unit generally considered earliest Devonian in age, is studied in terms of sedimentology and ichnology. The results show that the Xiaxishancun Formation typically records the deposition of hyperpycnal flow systems, which have been rarely reported in the Paleozoic. Three facies associations, including mudstone-dominated association, heterolithic association, and sandstone-dominated association, represent different parts of the channels and lobes of hyperpycnal subaqueous deltas on the shelf. Nineteen ichnogenera and 32 ichnospecies were distinguished in the Xiaxishancun Formation, and grouped into two ichnoassemblages, the Lockeia - Ptychoplasma - Oravaichnium ichnoassemblage in hummocky/swaley cross-stratified sandstones, and the Cruziana - Diplichnites - Monomorphichnus ichnoassemblage in thin rippled sandstone beds. The hyperpycnal depositional processes of the Xiaxishancun Formation created nutrient-rich, oxygen-rich, siliciclastic environments that supported diverse benthic ecosystems. Our study provides new insights into the understanding of marginal-marine environments and biotas of South China, immediately following the Silurian–Devonian transition event. • 32 ichnospecies reported from the Lower Devonian Xiaxishancun Formation. • Ichnoassemblages are helpful to analyze the sedimentary process of hyperpycnites. • Hyperpycnites developed in South China during the earliest Devonian. • Inceased terrestrial inputs improved Early Devonian marine community. [ABSTRACT FROM AUTHOR]

The trace fossil Rhizocorallium is abundant in the shallow‐marine settings of the Upper Devonian Wangguangou Formation in Xichuan, Henan Province, northern margin of the South China block. Based on its morphological characteristics, the studied Rhizocorallium is attributed to Rhizocorallium commune var. auriforme. There is a significant compositional difference between the fillings of the marginal tube and the spreite. The fillings in the marginal tube are similar to the surrounding rock, with abundant bioclasts. The fillings in the spreite are relatively fine‐grained and obviously affected by biological activities. Four types of pyrite framboids (pyritohedral, octahedron, cube and spherical) have been found within the Rhizocorallium. Moreover, the ratio of pyrite framboids diameter (D) to submicron crystal diameter (d) is <10, suggesting that they were formed by microbial activities. Relatively large pyrite framboids with smooth surface mainly occur in the marginal tube, while small pyrite framboids with sheath are abundant in the spreite. Energy spectrometer (EDS) analysis showed that the S/Fe ratio in the pyrite increased with decreasing crystal diameter, indicating different redox conditions in the marginal tube and the spreite. These features indicate that Rhizocorallium from the Xichuan section is not simply a foraging trace, but is probably a multi‐functional, complex burrow system utilized for living, caching and farming microorganisms. [ABSTRACT FROM AUTHOR]

New ichnological data from the Lower Triassic (Induan) Dongchuan Formation (Longmendong, South China) record the recovery interval of marginal-marine communities following the end-Permian mass extinction. Here, we document six ichnogenera from the upper part of the Dongchuan Formation of Dienerian (Early Triassic) age in the Longmendong area, Sichuan Province, South China. These are Cylindrichnus , Diplocraterion , Palaeophycus , Planolites , Siphonichnus , and Teichichnus , illustrating a depauperate Cruziana Ichnofacies. Facies analysis suggests that the depauperate Cruziana Ichnofacies is present in deposits recording the transition from fluvial to tide-dominated estuarine settings. Compilation of worldwide brackish-water ichnofaunas from Permian (average alpha ichnodiversity = 6.2) to Triassic (average alpha ichnodiversity = 5.5) suggests that no significant ichnodiversity decrease took place in these settings as a result of the mass extinction and further implies that the impact of the mass extinction may have been less severe in marginal-marine settings. Ichnofaunas in pre- and post-extinction marginal-marine environments are remarkably similar and tend to be dominated by facies-crossing ichnotaxa (e.g., Diplocraterion , Palaeophycus , Planolites ) produced by opportunistic faunas. [ABSTRACT FROM AUTHOR]

Widespread oceanic anoxia has been implicated as a killing mechanism during the end-Permian mass extinction (EPME). A high-resolution investigation of pyrite framboids and bioturbation structures in the Shangsi section of South China has revealed repeated and frequent fluctuations of coupled anoxic/euxinic to dysoxic/oxic episodes in the latest Permian, immediately preceding the EPME. Anoxic bottom waters and interstitial water conditions are documented by the smallest pyrite framboids (3–5 μm) and the absence of bioturbation, and dysoxic bottom waters and anoxic interstitial waters are inferred from larger pyrite framboids (6–10 μm) and the occurrence of Zoophycos. In comparison, oxic conditions for both bottom waters and interstitial waters are revealed by a high bioturbation index (BI = 4) and the occurrence of mid-tier Thalassinoides. Fluctuating pyrite framboid sizes and bioturbation structures suggest that bottom and interstitial oxygen levels were neither fully, nor persistently, anoxic/euxinic before the EPME, and instead recorded frequent periodic fluctuations between anoxic/euxinic and dysoxic/oxic conditions. The paleoceanic redox variation appears to correlate with the 405-ka eccentricity cycles in the anhysteretic remanent magnetization (ARM) series, suggesting that fluctuations might have been controlled by Milankovitch cycles. The role of fluctuations between anoxic/euxinic and dysoxic/oxic episodes in the latest Permian to the EPME is unclear, but it seems plausible that they represent a prelude to the highly stressed conditions that are characteristic of the EPME. • High-resolution of pyrite framboids and Bioturbation index was studied in the latest Permian. • Fluctuation of anoxic/euxinic–dysoxic/aerobic episodes during the latest Permian. • Upwelling controlled by Milankovitch cycles correlated with the paleoceanic redox change. [ABSTRACT FROM AUTHOR]

Dictyodora has been generally considered an ichnogenus with a restricted temporal range from the Cambrian to the Mississippian. Until now, there have been no reports of Dictyodora after the Mississippian. Here we report on well-preserved and abundant Dictyodora from deep-sea sediments of the Lopingian Maomaolong Formation in West Qinling, central China, which is hitherto the youngest occurrence of Dictyodora and extends the stratigraphic range of Dictyodora to the Late Permian. Two ichnospecies of Dictyodora are distinguished: D. zimmermanni and D. cf. scotica. Unlike the small-sized Dictyodora in the pre-Pennsylvanian, the three-dimensional morphology of Dictyodora studied here shows larger amplitudes and longer limbs with clearly inclined walls and basal burrows, which are interpreted to have been made by a soft-bodied worm-like organism with a snorkel-like organ as similarly documented in previous studies. Detailed systematic ichnological features and SEM and EDS results indicate that Dictyodora here is not simply a respiration structure made during the locomotion of the trace maker, but resulted from active filling by the trace maker. Dictyodora is probably not a good indicator of the deep-marine environment in the Paleozoic. From our dataset, Dictyodora originated from the shallow-marine environment in the early Cambrian, then migrated into the deep sea in the Ordovician and the marginal-marine setting in the Wenlock, and was finally restricted to the deep-marine environment in the Carboniferous and Permian. Both Psammichnites and Dictyodora are structures made by organisms with snorkel-like organs, and both were eliminated during the end-Permian mass extinction. • The youngest known Dictyodora was reported in the Late Permian. • The three radiation trends of Dictyodora were proposed in the Paleozoic. • Both Dictyodora and Psammichnites were extinct in the EPME. [ABSTRACT FROM AUTHOR]

Three undescribed sesquiterpenes, designed as pichinenoid A-C (1 – 3), along with nine known ones (4 – 12) were isolated from the stems and leaves of Picrasma chinensis. The new isolates including their absolute configurations were elucidated based on extensive spectroscopic methods, single crystal X-ray diffraction, and electronic circular dichroism (ECD) experiments, as well as comparison with literature data. Structurally, compounds 1 and 2 are descending sesquiterpenes, while pichinenoid C (3) is a rare sesquiterpene bearing a 2-methylenebut-3-enoic acid moiety at the C-6 side chain. All the isolated compounds were tested for their neuroprotective effects against the H 2 O 2 -induced damage on human neuroblastoma SH-SY5Y cells, and most of them showed moderate neuroprotective activity. Especially, compounds 1 , 3 – 5 , and 7 showed a potent neuroprotective effect at 25 or 50 μM. Moreover, the neuroprotective effects of compounds 1 and 4 were tested on a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinson's disease (PD) mouse model. Results of western blot and immunofluorescence indicated that compound 4 significantly counteract the toxicity of MPTP, and reversed the expression of tyrosine hydroxylase (TH) in substantia nigra (SN) and striatum (ST) of the mouse brain. Interestingly, western blot data suggested compound 4 also enhanced B-cell lymphoma-2 (Bcl-2) and heme oxygenase 1 (HO-1) expressions in the brain tissues from MPTP damaged mouse. [Display omitted] [ABSTRACT FROM AUTHOR]

Large numbers of densely distributed Rhizocorallium provide a window to understanding the behavioural and functional changes of the trace maker after extreme environmental events. This study focuses on the analysis of Rhizocorallium from the Middle Triassic (Anisian) limestones in the Boyun section, Yunnan Province, Southwest China to investigate the ecological strategies and ethological signatures of its producers before and after storm events. Based on its morphological features, the studied Rhizocorallium is attributed to two ichnospecies Rhizocorallium jenense and R. commune , the latter showing two varieties R. commune var. auriforme and R. commune var. irregulare. In addition to Rhizocorallium , the trace fossil assemblage consists of Arenicolites , Palaeophycus , Planolites and Thalassinoides , which allows assignation to the Cruziana ichnofacies associated with the shallow marine environment. The studied ichnofossil-bearing intervals in the Boyun section are usually high bioturbated, with BPBI (bedding plane bioturbation index) around 5. The ichnoassemblage has a relatively low ichnodiversity and shows high density of Rhizocorallium , which is interpreted as the result of the opportunist strategy when the Rhizocorallium trace makers exploited the quiet, nutrient-rich substrates after storm events. Crosscutting relationships between multiple levels of Rhizocorallium indicate that earlier burrows were reworked by later ones due to successive storm events and erosion of the shallow-tier burrows. Orientation of the marginal tubes of Rhizocorallium jenense shows a bidirectional pattern at 295°NW and 160°SE, which may record the changes of the main flow direction. Diameter measurements support the total recovery of the macrobenthic trace makers during the Middle Triassic (Anisian). • Abundant Rhizocorallium in Anisian carbonates was studied quantitatively. • Distribution and density of Rhizocorallium suggests a r-selected strategy. • This Rhizocorallium record is associated to storm events. • The behavioural pattern of Rhizocorallium trace makers is reconstructed. • The total recovery of the ecosystem occurred during the Middle Triassic. [ABSTRACT FROM AUTHOR]

We aimed to systematically evaluate the accuracy of nCD64 in diagnosing infection in patients with autoimmune diseases. Studies were searched in PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure, Wanfang, and Chongqing VIP databases up to October 2018. There was no restriction for language and age. Prospective studies examining the accuracy of nCD64 in diagnosing infection in patients with autoimmune diseases were included. The Quality Assessment of Diagnostic Accuracy Studies-2 tool was used to assess the quality of eligible studies. Stata 15.1 and Meta-DiSc 1.4 software were used for data analysis. Eleven studies fulfilled the inclusion criteria (677 patients, 229 patients with bacterial infection, and 448 without infection). The pooled sensitivity and specificity of nCD64 were 89% (95% confidence interval (CI) 82–93) and 94% (95% CI 91–96), respectively. The pooled positive likelihood ratio and negative likelihood ratio were 14.9 (95% CI 9.3–23.8) and 0.12 (95% CI 0.07–0.20), respectively. The diagnostic odds ratio and area under the summary receiver operating characteristic curve were 123 (95% CI 53–283) and 0.97 (95% CI 0.95–0.98), respectively. The univariate meta-regression analysis showed that region, type of disease, antibiotic therapy, and presentation of nCD64 measurement results were responsible for the heterogeneity. The Deeks' funnel plot asymmetry test showed that there was no publication bias (p = 0.15). nCD64 has a good overall diagnostic performance for differentiating infection from disease flare in patients with autoimmune diseases. Further studies are needed to confirm the optimized cutoff value. [ABSTRACT FROM AUTHOR]

[Display omitted] • Two types of quartz with distinct trace element chemistry present in the Xiangzhong metallogenic province. • Relative acidic and stable ore-forming fluid from the Xikuangshan deposit experienced water–rock reaction. • Less acidic ore-forming fluids underwent fluid mixing in the Woxi, Banxi and Zhazixi deposits. • Magmatic-hydrothermal system possibly provided some ore-forming fluid for the Woxi, Banxi, and Zhazixi deposits. Despite the Xiangzhong metallogenic province being globally the most important ore-concentrated area of antimony (Sb) mineralization, the genesis of Sb-(Au-W) deposits in this region is still under debate. In this study, trace element compositions of hydrothermal quartz from four representative Sb-(Au-W) deposits (Xikuangshan, Woxi, Banxi, and Zhazixi) in the Xiangzhong metallogenic province have been investigated to constrain the origin of ore-forming fluids and physiochemical conditions of Sb mineralization. The fs LA-ICP-MS data indicate that Li, B, Na, Al, P, K, and Sb are relatively enriched in quartz, probably mainly incorporated into the quartz crystal lattice, and dominated by the coupled substitution of (Al3+, Sb3+, B3+) + (Li+, Na+, K+, H+) ↔ Si4+ and (Al3+, Sb3+, B3+) + P5+ ↔ 2Si4+. In the Xikuangshan Sb deposit, charge-neutrality conditions of cations reveal that (Al3+, Sb3+) + Li+ ↔ Si4+ is the most important substitution mechanism in quartz from early-stage Sb mineralization (quartz-stibnite veins), whereas (Al3+, Sb3+) + (Li+ + H+) ↔ Si4+ may control the trace element contents in quartz from late-stage Sb mineralization (calcite-quartz-stibnite veins). The relatively high Al content and the low variability in trace element content suggest that quartz from the Xikuangshan Sb deposit may have precipitated from a relatively acidic and stable ore-forming fluid. Combined with the high Sr and Rb contents of quartz, a plausible explanation is that acidic hydrothermal fluids promoted water–rock reaction that dissolved large amounts of Sr and Rb, resulting in the high Al, Rb, and Sr contents in crystallized quartz from the Xikuangshan Sb deposit. In contrast, the relatively low but inhomogeneous Al content indicates that quartz from the Woxi and Banxi Sb-(Au-W) deposits may have precipitated from a less acidic ore-forming fluid and supports the idea of fluid mixing. More importantly, the relatively high contents of Rb, Ge, and Ti in quartz from the Woxi and Banxi Sb-(Au-W) deposits, combined with the low Al and Sr contents, imply that magmatic-hydrothermal systems possibly contributed to the ore-forming fluids. Based on the trace element compositions of quartz, two major types of Sb deposits were identified in the Xiangzhong metallogenic province: the giant Xikuangshan epithermal deposit in which the ore-forming fluids are relatively acidic, stable and have experienced water–rock reaction, generally similar to the Qinglong Sb deposit in the Youjiang metallogenic province. The second type is the orogenic-type deposit represented by the Woxi Sb-Au-W deposit, including the Banxi Sb deposit, where the ore-forming fluids have undergone fluid mixing and relatively weak water–rock reaction, and may have been joined by a small amount of magmatic-hydrothermal fluids. Together with the recently published Sb mineralization ages (149–144 Ma) of the Woxi Sb-Au-W deposit, it supports the idea that this type of Sb deposit is related to the Mesozoic magmatism. The Zhazixi Sb-W deposit shows transitional features between these two types of Sb deposits. [ABSTRACT FROM AUTHOR]

Abstract: High-throughput screening enzyme-linked immunosorbent assay (HTS-ELISA) method was used for screening of hybridoma cells that secret high-affinity anti-zearalenone (ZON) monoclonal antibody (mAb). Recovery rate of ZON from spiked corn samples was between 80% and 128%. The cross-reactivities of the anti-ZON mAb against ZON, β-zearalenol, α-zearalanol, β-zearalanol, deoxynivalenol and aflatoxin B1 were 100%, 24.1%, 189.1%, 43.9%, <1.0%, <1.0%, respectively. The limit of detection for ZON was 0.1 ng/g. The linear range for the developed indirect competitive ELISA was 0.5–10 ng/g. The half maximal (50%) inhibitory concentration (IC50) of the anti-ZON mAb was 1.79 ng/g. In total, 137 samples of corn, powdered corn, and processed corn products were collected from farms and supermarkets in northeastern China. Of 42 corn samples tested, 4 (9.5%) samples contained ZON 5–60 ng/g, 4 (9.5%) samples contained 60–500 ng/g, In 34 (81%) samples ZON was not detected. Of 15 powered corn samples, only 1 (6.7%) sample contained 5–60 ng/g, and no ZON was detected in 80 processed corn products. [Copyright &y& Elsevier]

Abstract: The peroxisome proliferator-activated receptors (PPARs)-α,-β/δ and -γ are the ligand-activated transcription factors that function as the master regulators of glucose, fatty acid and lipoprotein metabolism, energy balance, cell proliferation and differentiation, inflammation and atherosclerosis. This study examined the main effects of both single-locus and multilocus interactions among genetic variants in Chinese Han individuals to test the hypothesis that PPAR-α/δ/γ polymorphisms may contribute to the etiology of hypertriglyceridemia independently and/or through such complex interactions. We genotyped 9 single nucleotide polymorphisms for PPAR-α/δ/γ. Participants were recruited from the Prevention of MetS and Multi-metabolic Disorders in Jiangsu Province of China Study. 820 subjects (474 non-hypertriglyceridemia subjects, 346 hypertriglyceridemia subjects) were randomly selected. Single-locus analyses showed that after adjusted for age, sex, smoking, alcohol consumption, body mass index, waist circumference and fasting glucose, rs1800206, rs9794, rs3856806 and rs1805192 were significantly associated with hypertriglyceridemia, the OR (95% CI) were 4.43(3.08–6.37), 1.49(1.10–2.02), 1.56(1.16–2.08), 2.43(1.80–3.29), respectively. Further, generalized multifactor dimensionality reduction method analysis showed that two-to-six-locus and eight-locus models were significant (p<0.05), which indicated a potential gene–gene interaction among PPAR-α/δ/γ polymorphisms. The results suggest that PPAR-α/δ/γ polymorphisms may contribute to the risk of hypertriglyceridemia independently and/or in an interactive manner. [Copyright &y& Elsevier]

The carbonate rocks of the Ordovician Majiagou Formation from the northwestern part of Henan Province and their diverse trace fossils provide an outcrop analogue for bioturbated, low porosity and low permeability carbonate reservoirs. Three ichnofabrics can be defined based on the ichnotaxonomy, ichnodiversities, individual abundances and overall bioturbation indices. The Balanoglossites ichnofabric represented medium to relatively high-energy sedimentary environments such as intertidal zone and subtidal shoals in the carbonate platform. The Planolites ichnofabric suggested relatively low-energy, protected sedimentary environments such as lagoons in a restricted carbonate platform, but also occurs in the deeper-water depressions in the open carbonate platform. The Chondrites ichnofabric characterized low-energy and reduced oxygen conditions, with burrows penetrating below a shallow redox interface in deeper-water settings that include the distal slope as well as local depressions in the open carbonate platform. Our analysis suggests that the modifications of petrophysical parameters are controlled or influenced by the ichnofabric characteristics (burrow architecture, burrow cross-cutting relationship, degree of bioturbation and burrow connectivity), the permeability contrast between burrow-fills and matrix, and the dolomitization of burrow-fills. The micritic host sediments have negligible porosity and permeability. The bioturbated sediments have significant differences in fabric, texture, porosity and permeability. The burrow-fills are very commonly dolomitised. Each of the burrow-types can enhance reservoir properties, but the greatest differences are associated with the Balanoglossites ichnofabric, in which porosity and permeability can reach over 2% and 70 mD. Preliminary stratigraphic studies indicate that reservoir potential in the subsurface will be linked to an understanding of the distribution of shoal and intertidal facies as well as their associated Balanoglossites ichnofabrics. [ABSTRACT FROM AUTHOR]