Delayed build-up of Arctic ice sheets during 400,000-year minima in insolation variability.

Knowledge of the past variability of climate at high northern latitudes during astronomical analogues of the present interglacial may help to inform our understanding of future climate change. Unfortunately, long-term continuous records of ice-sheet variability in the Northern Hemisphere only are scarce because records of benthic (18)O content represent an integrated signal of changes in ice volume in both polar regions. However, variations in Northern Hemisphere ice sheets influence the Siberian High (an atmospheric pressure system), so variations in the East Asian winter monsoon (EAWM)--as recorded in the aeolian dust deposits on the Chinese Loess Plateau--can serve as a useful proxy of Arctic climate variability before the ice-core record begins. Here we present an EAWM proxy record using grain-size variations in two parallel loess sections representative of sequences across the whole of the Chinese Loess Plateau over the past 900,000 years. The results show that during periods of low eccentricity and precessional variability at approximately 400,000-year intervals, the grain-size-inferred intensity of the EAWM remains weak for up to 20,000 years after the end of the interglacial episode of high summer monsoon activity and strong pedogenesis. In contrast, there is a rapid increase in the EAWM after the end of most other interglacials. We conclude that, for both the 400,000-year interglacials, the weak EAWM winds maintain a mild, non-glacial climate at high northern latitudes for much longer than expected from the conventional loess and marine oxygen isotope records. During these times, the less-severe summer insolation minima at 65° N (ref. 4) would have suppressed ice and snow accumulation, leading to a weak Siberian High and, consequently, weak EAWM winds.

Efficacy and safety of hepatic arterial infusion chemotherapy combined with lenvatinib and sequential ablation in the treatment of advanced hepatocellular carcinoma.

PURPOSE: Evaluate the efficacy and safety of triple therapeutic method (Hepatic Aarterial Infusion Chemotherapy-HAIC, lenvatinib and sequential ablation) in the treatment for Advanced Hepatocellular carcinoma (Ad-HCC). MATERIALS AND METHODS: From November 2018 to June 2021, data from 150 consecutive Ad-HCC patients were collected. All patients received HAIC combined with lenvatinib (H-L group, n = 97) or HAIC combined with lenvatinib and sequential ablation (H-L-A group, n = 53). Complications, overall survival (OS), progression-free survival (PFS) and intrahepatic progression-free survival (IPFS) were compared between both groups. RESULTS: No significant differences of baseline characteristics were found between groups. The time of median follow-up was 17.8 months (range, 6.8, 37.6 months). In comparison to the H-L group, the H-L-A group patients showed significantly longer median OS (>30 months vs 13.6 months, respectively; p = 0.010), PFS (12.8 vs. 5.6 months, respectively; p < 0.001), and IPFS (14.6 vs. 6.8 months, respectively; p = 0.002). According to the results from uni- and multivariable analyses, we considered α-fetoprotein and treatment modality as two survival independent prognostic factors. No significant change of the complication incidences was observed between H-L group and H-L-A group (12.4% vs. 11.3%, p = 0.890). CONCLUSION: Compared to HAIC combined with lenvatinib only, HAIC combined with lenvatinib and sequential ablation was safer and more effective, improving survival outcomes of Ad-HCC patients. A prospective study will be designed validate the retrospective results.

Atmospheric mercury accumulation rate in northeastern China during the past 800 years as recorded by the sediments of Tianchi Crater Lake.

An evaluation of the history of anthropogenic mercury (Hg) emissions is needed to quantify total atmospheric Hg emissions since the Industrial Revolution. Thus more long-term records of Hg accumulation rate from natural archives are needed. In the present study, a sediment core from Tianchi Lake, a crater lake in northeastern China, was used to reconstruct atmospheric Hg accumulation rates during the past 800 years. The results show that both Hg concentration and Hg accumulation rate began to increase from 29.5 to 40.2 ng g-1 and from 1.44 to 2.26 µg m-2 yr-1, respectively, at ~ 1750 AD, synchronous with the initiation of the Industrial Revolution. The Hg accumulation rate and Hg concentration increased significantly at ~ 1850 AD, and subsequently, there were two prominent peaks, at ~ 1940 AD and ~ 1980 AD, which are temporally consistent with the Second World War and the peak in commercial usage of Hg, respectively. The Hg accumulation rate and Hg concentration decreased after ~ 1980 AD, possibly because of the decrease in the global Hg background at that time. Differences in regional Hg emissions and atmospheric circulation may be responsible for the different trends in Hg accumulation rate after ~ 1980 AD in the Tibetan Plateau and northeastern China. Our results provide new data for evaluating natural and anthropogenic Hg emissions to the atmosphere in China.