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Lead (Pb) pollution emission from China is becoming a potential worldwide threat. Pb isotopic composition analysis is a useful tool to accurately trace the Pb sources of aerosols in atmosphere. In this study, a comprehensive data set of Pb isotopes for coals, Pb/Zn ores, and fuels from China was presented. The ratios of Pb/Pb and Pb/Pb in the coals were in the range of 1.114-1.383 and 1.791-2.317, similar to those from Europe, Oceania, and South Asia, but different from those from America (p < 0.01). The Pb/Zn ores had Pb/Pb and Pb/Pb in 1.020-1.183 and 2.088-2.309, less radiogenic than the coals. Leaded gasolines showed similar Pb isotopic compositions to Pb/Zn ores, with unleaded gasolines and diesels being mixed sources. The average Pb isotopic ratios of gasolines and diesels were significantly different (p < 0.01) from those of coals in China, leading to the possibility to discriminate Pb in fuels from in coals. Urban aerosols demonstrated similar Pb isotopic compositions to coals, Pb/Zn ores, and fuels in China. After removing the leaded gasoline, the Pb in aerosols is more radiogenic, supporting the heavy contribution of coal combustion to the atmospheric Pb pollution.

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U-Pb dating was made by the LA-ICP-MS method for detrital zircons from the Wudangshan volcanic-sedimentary succession in the South Qinling. Samples comprise quartz sandstones of the Wudangshan Group collected from the base of the Yangping Formation and an upper layer of the Shuangtai Formation overlain its volcanic sequence, and two river-sand collections from the drainage systems cutting across the two formations, respectively. The results show that the Yangping detrital zircons are dominated by 830-780 Ma grains with a minor population of ~1.0-0.84 Ga and sporadic grains of ~2.6, ~2.4 and 2.0 Ga, whereas the Shuangtai zircons yield an upper intercept age of 763±33 Ma, identical to the timing of the Wudangshan volcanism within error, with few concordant grains of 1.9 and 0.86 Ga. Age spectra for the two river-sand samples are similar to those of the Yangping and Shuangtai Formations, respectively. It thus suggests that the Wudangshan strata are less than 780 Ma, whereas their major detrital zircon populations of 1.0-0.85 Ga and 830-780 Ma are consistent with timing of the Hannan magmatic activities along the northwestern margin of the South China Block. This suggests a Hannan or adjacent area provenance for the Wudangshan strata. The Wudang area is characterized by rift-related igneous events at ~755 and ~680 Ma, respectively, pointing to a tectonomagmatic history different from the Hannan area. It is inferred that the ~755 Ma magmatism is likely to indicate a separation of the South China Block from the supercontinent Rodinia, while the ~680 Ma event suggests a further split between the South Qinling and some unknown continent. Detrital zircon, U-Pb geochronology, South Qinling, South China Block, Neoproterozoic evolution Citation:Ling W L, Duan R C, Liu X M, et al. U-Pb dating of detrital zircons from the Wudangshan Group in the South Qinling and its geological significance.

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Background The clinical efficacy of electroacupuncture in treating diabetic peripheral neuropathy (DPN) is significant, but the underlying mechanism of action is not clear. Considering that glucose‐regulated protein 78 (GRP78) and caspase‐12 are major proteins participating in cell apoptosis, we investigated the effects of “adjusting internal organs and dredging channel” electroacupuncture therapy on GRP78 and caspase‐12 levels in streptozotocin (STZ)‐diabetic rats to elucidate the mechanism of action. Methods Rats were first divided into two groups: one group was rendered diabetic with a single injection of 50 mg/kg STZ, whereas the other normal control group was injected with an equivalent volume of citrate buffer. The STZ‐diabetic rats were randomly divided into three groups: model control and electroacupuncture‐ and mecobalamin‐treated groups. After 12 weeks treatment, the therapeutic efficacy of electroacupuncture was assessed using sciatic nerves isolated from rats. In the electroacupuncture group, rats were treated by electroacupuncture for 20 minutes once daily for 6 days each week, with 1 day off, for 12 consecutive weeks. The selected acupressure points include bilateral acupressure points of BL13 (Fehu), BL20 (Pishu), BL23 (Shenshu), LI4 (Hegu), LR3 (faichong), ST36 (Zusanli), and SP6 (Sanyiniiao). Acupressure points were stimulated using a HuaTuo SDZ‐V Electric Acupuncture Therapy Apparatus. The acupressure points of BL13 and BL23, as well as SP6 and LR3, were connected on the same side with a dilatational wave of 3 Hz (frequency ratio of 1 : 5) to stimulate the parts of the body to the extent that could be tolerated by the rat. As for the mecobalamin‐treated groups, mecobalamin was administrated to rats intragastrically at a dose of 20 mg/kg once daily for 12 consecutive weeks. Immunofluorescence and western blot analysis were used to determine GRP78 and caspase‐12 levels in sciatic nerves. In addition, cell apoptosis in sciatic nerves was determined using the terminal deoxyribonucleotidyl transferase‐mediated dUTP‐digoxigenin nick end‐labeling (TUNEL) assay. Results Electroacupuncture markedly reduced the pathological injury to sciatic nerves in STZ‐diabetic rats. Moreover, electroacupuncture significantly downregulated GRP78 and caspase‐12 and reduced cell apoptosis of sciatic nerves in DPN rats. Conclusions Electroacupuncture improved DPN by downregulating GRP78 and caspase‐12 and reducing cell apoptosis of sciatic nerves in STZ‐diabetic rats, and further inhibited the occurrence of endoplasmic reticulum stress, thus preventing sciatic nerve injuries.

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