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Hepatocellular carcinoma (HCC) is one of the most common malignancies with poor prognosis, and novel treatment strategies are urgently needed. Mitochondria are key regulators of cellular homeostasis and potential targets for tumor therapy. Here, the role of mitochondrial translocator protein (TSPO) in the regulation of ferroptosis and antitumor immunity is investigated and the potential therapeutic implications for HCC are assessed. TSPO is highly expressed in HCC and associated with poor prognosis. Gain‐ and loss‐of‐function experiments present that TSPO promotes HCC cell growth, migration, and invasion in vitro and in vivo. In addition, TSPO inhibits ferroptosis in HCC cells via enhancing the Nrf2‐dependent antioxidant defense system. Mechanistically, TSPO directly interacts with P62 and interferes with autophagy, leading to the accumulation of P62. The P62 accumulation competes with KEAP1, preventing it from targeting Nrf2 for proteasomal degradation. Furthermore, TSPO promotes HCC immune escape by upregulating PD‐L1 expression through Nrf2‐mediated transcription. Notably, TSPO inhibitor PK11195 combines with anti‐PD‐1 antibody showing a synergistic anti‐tumor effect in a mouse model. Overall, the results demonstrated that mitochondrial TSPO promotes HCC progression by inhibiting ferroptosis and antitumor immunity. Targeting TSPO can be a promising new strategy for HCC treatment. [ABSTRACT FROM AUTHOR]

Arid and semiarid regions are environmentally vulnerable to global warming. Thus, studying their environmental history during warm periods (e.g., the Last Interglacial, LIG) is crucial for understanding their future changes too. The West Gobi Desert is a transitional zone influenced by the westerlies and the East Asian monsoon system. Therefore, the variation in atmospheric circulation profoundly affects its water vapor transport and landscape evolution. Due to the scarcity of continuous records, the moisture transport process remains ambiguous, which limits further research on paleolake evolution and aeolian activity. Here, we combine paleoclimate simulations from the Coupled Model Intercomparison Project 6 (CMIP6)-Paleoclimate Modeling Intercomparison Project 4 (PMIP4) and geological records to clarify the water vapor transport pathways and aeolian activity in the West Gobi Desert during the LIG, compared to the reference period (the piControl). Our results show that increased rainfall and meltwater were possible supplies for surface water during the LIG and were associated with enhanced East Asian summer monsoon and higher surface air temperatures. Concomitantly, weakening aeolian activity and dormant dune fields occurred in the West Gobi Desert, resulting from higher surface moisture content and weaker surface wind regimes associated with the weakening westerlies and East Asian winter monsoon. Notably, the limited weakening of aeolian activity that occurred in the LIG winter and spring was caused by weaker surface wind and deteriorating surface moisture conditions, while the significant dormancy of dune fields in the LIG summer and autumn was initiated by the combined effects of ameliorative surface moisture conditions and lower surface wind speed. • West Gobi Desert water supply rose due to stronger East Asian summer monsoon and warm climate during the Last Interglacial (LIG). • Weaker winds and higher moisture led to dormant aeolian activity in West Gobi Desert during the LIG. • LIG warm season saw more significant weakening of aeolian activity than the cold season in West Gobi Desert. [ABSTRACT FROM AUTHOR]

Numerous studies have explored paleoenvironmental conditions in China's dune fields around the mid-Holocene (MH), ∼6000 calendar years ago, often based on individual paleosol-aeolian sand depositional sequences and local-scale landscape dynamics. So far, continent-scale modeling studies have only indirectly assessed dune activation and stabilization processes via changes in simulated precipitation, net precipitation (precipitation minus evaporation), and effective moisture (precipitation divided by evaporation). Here we conducted a comprehensive study using gridded data on potential evapotranspiration, precipitation, and surface wind velocity from 13 climate models participating in the Paleoclimate Modeling Intercomparison Project phases 4 (PMIP4) and compared the model results with geological records. Our evaluation of spatial patterns of dune activity in northern China around the MH reveals that the intensity of annual MH dune activity exhibited significant differences between the eastern and western parts of Chinese deserts compared to those of the preindustrial period (PI). Dune activity was significantly weaker in the eastern region, while in the western part, it was considerably stronger. The key drivers of this disparity were the distinct spatial variations in near-surface wind speed and effective moisture between the two regions. Compared with the optically stimulated luminescence ages of the paleosol-aeolian sand sedimentary sequences derived from a compilation of geological records from 88 sites across northern China, the model results suggest that the weakening of dune activity and the process of dune stabilization in eastern China around the MH were mainly attributed to a significant increase in effective moisture and a concurrent decrease in near-surface wind speed due to the intensified East Asian summer monsoon. Additionally, the weakening of westerlies in western China resulted in reduced effective moisture, contributing to increased sand availability for dune development and subsequent desert expansion. • Mid-Holocene dune activity in Chinese deserts varied regionally, differing from preindustrial period. • Varied wind speed and moisture caused different mid-Holocene aeolian activities in northern China's western and eastern desert belt. • Numerical simulations aid in interpreting field-based geological findings comprehensively. [ABSTRACT FROM AUTHOR]

Irisin is a newly discovered exercise-induced cytokine, produced by the proteolytic hydrolysis of fibronectin type III domain-containing protein 5 (FNDC5). Irisin is widely distributed in the human body and is involved in the browning of white adipose tissue, improving insulin resistance, improving cognitive function, and regulating bone metabolism. Recent studies have shown that irisin concentration is elevated in a variety of tumor tissues as compared with that in normal tissues. However, irisin has different effects on the proliferation and apoptosis of tumor cells in breast cancer, lung cancer, and liver cancer through various mechanisms. Irisin plays an important role in the occurrence, development, and metastasis of different tumors, suggesting that irisin can be used as a potential target for tumor diagnosis and treatment. Therefore, studying the expression and function of irisin in tumors may be of great significance for the prevention and treatment of tumors. This article reviews the research progress on the role of irisin in tumors. [ABSTRACT FROM AUTHOR]

Introduction: Irisin is a newly identified cytokine that has gained increasing attention because of its potential therapeutic applications in metabolic diseases and human cancers. Recently, accumulating evidence indicates that irisin plays an important role in the development and metastasis of various tumors. The aim of this study was to evaluate the effects and underlying mechanisms of irisin on malignant growth of pancreatic cancer cells. Materials and methods: The anti-proliferative effect of irisin was examined using the CCK-8 assay. Irisin-induced apoptosis was determined by the annexin V-FITC/PI staining assay. The effects of irisin on cell migration and invasion were assessed using the scratch-induced wound healing assay and transwell invasion assay, respectively. The expression and phosphorylation of signaling proteins were detected by Western blot analysis. Results: Our results showed that irisin inhibited cell proliferation and induced apoptosis of pancreatic cancer cells in a dose-dependent manner. In addition, irisin decreased the migration and invasion of pancreatic cancer cells. Finally, Western blot analysis revealed that irisin downregulated the PI3K/AKT signaling pathway. Conclusion: Our findings suggest that irisin is a novel therapeutic agent for pancreatic cancer. [ABSTRACT FROM AUTHOR]

Hepatocellular carcinoma (HCC) is one of the most lethal tumor types worldwide. Glycosylation has shown promise in the study of tumor mechanisms and treatment. The glycosylation status of HCC and the underlying molecular mechanisms are still not fully elucidated. Using bioinformatic analysis we obtained a more comprehensive characterization of glycosylation of HCC. Our analysis presented that high glycosylation levels might correlate with tumor progression and poor prognosis. Subsequent Experiments identified key molecular mechanisms for ST6GALNAC4 promoting malignant progression by inducing abnormal glycosylation. We confirmed the contribution of ST6GALNAC4 to proliferation, migration, and invasion in vitro and in vivo. Mechanistic studies revealed that ST6GALNAC4 may be induced abnormal TGFBR2 glycosylation, resulting in the higher protein levels of TGFBR2 and TGF β pathway increased activation. Our study also provided a further understand of immunosuppressive function of ST6GALNAC4 through T antigen-galectin3+ TAMs axis. This study has provided one such possibility that galectin3 inhibitors might be an acceptable treatment choice for HCC patients with high T antigen expression. [ABSTRACT FROM AUTHOR]

[Display omitted] • "Yardang-controlled dune" is systematically illustrated with morphology and dynamics. • In three patterns, dunes form before, beside and behind the yardangs. • CFD simulations reveal that the yardang-induced low-velocity winds shape the dunes. • Remote sensing measurements support the CFD, which agrees with three patterns. • The aspect ratios of the streamlined yardangs control the linear dune formation. The yardang-dune coexistence and the control of yardangs on dune formation reveal the joint action of wind erosion and deposition. Yardangs exhibit distinctive characteristics of streamlining and clustering, which apply unique and complicated impacts on the wind field and sand transport. However, previous studies lack systematic investigation on how yardangs exert control over dune morphology, and the intricate wind dynamics and mechanisms involved remain unclear. In this study, the "yardang-controlled dune" is systematically illustrated, supported by thorough studies of the yardang-controlled dune morphology and dynamics. Through the monitoring of the 6722 km2 dunes in the Qaidam Basin (QB), three typical yardang-dune coexistence patterns are identified and summarized: Pattern I-windward dune, crescentic dunes form on the upwind sides of the sparsely arranged yardangs; Pattern II-corridor dune, crescentic dunes form beside the narrowly arranged yardangs in the corridors and migrate; Pattern III-leeward dune, linear dune forms on the downwind side from isolated yardang tail. Computational fluid dynamics (CFD) modeling is used to analyze the dynamics and mechanisms of the three patterns and the corresponding real yardang topographies. CFD simulations show that with the control of yardangs, the winds in the locations corresponding to the dunes have significantly low velocities, leading to the wind entrainment decrease, sand accumulation and subsequent dune formation. CFD also reveals that the aspect ratios of yardangs control the formations of wind shadows and linear dunes on the yardang tails. The simulation results agree well with the actual landforms observed in the QB of the three patterns. Additionally, the dune leeward slope width and migration velocity statistics based on remote sensing provide further support for the observations and simulations. This study sheds light on the intricate influences of yardangs on wind deposition, underscoring their role in shaping the landform of dunes. [ABSTRACT FROM AUTHOR]

SUMMARY: Rosa roxburghii and Rosa sterilis, two species belonging to the Rosaceae family, are widespread in the southwest of China. These species have gained recognition for their remarkable abundance of ascorbate in their fresh fruits, making them an ideal vitamin C resource. In this study, we generated two high‐quality chromosome‐scale genome assemblies for R. roxburghii and R. sterilis, with genome sizes of 504 and 981.2 Mb, respectively. Notably, we present a haplotype‐resolved, chromosome‐scale assembly for diploid R. sterilis. Our results indicated that R. sterilis originated from the hybridization of R. roxburghii and R. longicuspis. Genome analysis revealed the absence of recent whole‐genome duplications in both species and identified a series of duplicated genes that possibly contributing to the accumulation of flavonoids. We identified two genes in the ascorbate synthesis pathway, GGP and GalLDH, that show signs of positive selection, along with high expression levels of GDP‐d‐mannose 3′, 5′‐epimerase (GME) and GDP‐l‐galactose phosphorylase (GGP) during fruit development. Furthermore, through co‐expression network analysis, we identified key hub genes (MYB5 and bZIP) that likely regulate genes in the ascorbate synthesis pathway, promoting ascorbate biosynthesis. Additionally, we observed the expansion of terpene synthase genes in these two species and tissue expression patterns, suggesting their involvement in terpenoid biosynthesis. Our research provides valuable insights into genome evolution and the molecular basis of the high concentration of ascorbate in these two Rosa species. [ABSTRACT FROM AUTHOR]

The development and transformation of barchan-parabolic dune can be led by vegetationestablishment, which may be induced by climate change (precipitation, temperature, andwind strength) and/or human intervention. The impact of wind strength change-inducedvegetation restoration on dunes morphology and theirs surface sedimentary features isneglected in the Maowusu Sandy Land. In this study, we combined datasets of NormalizedDifference Vegetation Index (NDVI) and climatic factors to analyze temporal changes invegetation growth and their response to changes in temperature, precipitation and windstrength in the northern margin of Maowusu Sandy Land from 1982 to 2015. Growing seasonNDVI is related to the significant decrease in drift potential (DP) during the entire studyperiod. Further temporal analyses indicate that the growing season NDVI trends are largelycontributed by wind strength and temperature changes during the earlier study period1982-2006. And then, the increasing NDVI is consistent with the slightly increasing trend ofprecipitation during the recent study period 2006-2015. Thus, the transformation ofthe transitional dune cannot be explained by the increasing trend of wind strengthchange-induced vegetation alone. During the recent period, once dunes are covered byvegetation, the change in wind strength cannot mobilize the stable dunes becausethe vegetation provides an effective buffer preventing sand erosion. To reveal theresponse of sedimentological reorganization during the dune transformation processes,grain-size characteristics along the longitudinal profile of three different types of duneswere examined. From barchan dune through transition dune to parabolic dune, withthe increase of the fine sands (125-250μm) proportions, the mean grain size MZgradually decreases; in addition, as the very fine sands (<125μm) class increases, thesorting σ1 of sand dunes gradually became worse. The decreasing wind strengthlead to partly transport of fine sands on the upper part of dune windward slope,resulting in the progress coarsening and the reduction of dune height at the crestarea. No distinct trend in sorting and mean grain size on the windward slope oftransition dune, indicating that sand in transport had little influence on the particle sizedistributions. Conversely, the progressive of sorting and coarsening of sands towards thecrest of parabolic dune, implying that vegetation limited the sands from upwind ofdune, changed the effective source of dune into the underlying source deposits orreworking pre-existing aeolian deposits and trapped the sands on the crest area. [ABSTRACT FROM AUTHOR]

This paper presents the environmental history and its responses to palaeoclimatic changes since the start of the Holocene in the eastern portion of the desert belt (sand seas and sandy lands) in northern China by comparing the aeolian sandpalaeosol sequences and their palaeoclimatic proxies. The optically stimulated luminescence (OSL) ages of the aeolian sandpalaeosol sedimentary sequences and a series of palaeoenvironmental proxies show that: (1) The large-scale dune landscape currently in the Kubuqi Sand Sea was formed during the Holocene in general; and the palaeosol was generally developed during the period of 4–2 ka, indicating conditions favorable for vegetation growth, soil development, and organic carbon accumulation due to increased precipitation or effective moisture and weakened aeolian activities; the large-scale expansion of dunes in the recent 2 ka is closely linked to human activities. The variable discharge of the Yellow River with diversions for irrigation may have resulted in a more consistent supply of aeolian particles for dune field expansion. (2) The dune landscape of the Hunshandake Sandy Land was likely formed around 12 ka, and before this, the western part of the Hunshandake Sandy Land would have been covered by a single large lake; it was obviously wetter than today in the sandy land during the period of 9.6–3 ka and the palaeosols were developed at the same time. But the aeolian activities have not been completely dormant in this long-lasting wetter epoch; because the Holocene wetter period was likely time-transgressive across the region. (3) The palaeosol of the Hulunbuir Sandy Land began to develop as early as 14.5 ka, probably continuing until the last 2 ka. The palaeosol development of various dune fields in the eastern portion of the desert belt (sand seas and sandy lands) in northern China is spatially heterogeneous, and even the palaeosol development time in different locations within each sandy land is inconsistent. During the middle Holocene (especially the 7.5–3.5 ka), all the sandy lands were stabilized in general and the intensity of aeolian activities was significantly weakened. The number of palaeoenvironmental records in the eastern portion of the desert belt (sand seas and sandy lands) in northern China has increased rapidly in the past decade, but the amount of published data still does not match the vast extent of the dune fields. It does require much more in-depth palaeoenvironmental studies for a full understanding of the relationship between aeolian activities and climate change in northern China. [ABSTRACT FROM AUTHOR]

Background: Circular RNAs (circRNAs) play a significant role in the initiation and progression of various cancers, including hepatocellular carcinoma (HCC). Circular syntaxin 6 (circSTX6, also known as hsa_circ_0007905) has been identified as a microRNA (miRNA) sponge in pancreatic adenocarcinoma. However, its full range of functions in terms of protein scaffold and translation remain largely unexplored in the context of HCC. Methods: The expression of circSTX6 and its encoded protein was examined in HCC tumour tissues. N6‐methyladenosine (m6A) on circSTX6 was verified and quantified by methylated RNA immunoprecipitation (Me‐RIP), RIP and dual luciferase reporter assays. The biological functions of circSTX6 and its encoded protein in HCC were clarified by in vitro and in vivo experiments. Mechanistically, the interaction between circSTX6 and heterogeneous nuclear ribonucleoprotein D (HNRNPD) was investigated by RNA pull‐down, RIP and fluorescence in situ hybridization (FISH)/IF. The regulatory effects of circSTX6 and HNRNPD on activating transcription factor 3 (ATF3) mRNA were determined by mRNA stability and RIP assays. Furthermore, the presence of circSTX6‐encoded protein was verified by mass spectrometry. Results: CircSTX6 and its encoded 144 amino acid polypeptide, circSTX6‐144aa, were highly expressed in HCC tumour tissues and served as independent risk factors for overall survival in HCC patients. The expression of circSTX6 was regulated by METTL14 in an m6A‐dependent manner. Functionally, circSTX6 accelerated HCC proliferation and tumourigenicity and reinforced tumour metastasis in vitro and in vivo. Mechanistically, circSTX6 acted as a sponge for HNRNPD protein, facilitating its binding to ATF3 mRNA, consequently promoting ATF3 mRNA decay. Meanwhile, circSTX6‐144aa promoted HCC proliferation, migration and invasion independent of circSTX6 itself. Conclusion: Collectively, our study reveals that m6A‐modified circSTX6 drives malignancy in HCC through the HNRNPD/ATF3 axis, while its encoded circSTX6‐144aa contributes to HCC progression independent of circSTX6. CirSTX6 and its encoded protein hold promise as potential biomarkers and therapeutic targets in HCC. [ABSTRACT FROM AUTHOR]

[Display omitted] [ABSTRACT FROM AUTHOR]

The potential interactions between aeolian and fluvial systems are critical in understanding environmental change. Whether aeolian products originated from the river depends on the river characteristics and wind regimes. In southern Tibet, aeolian sand dunes are widespread along the Yarlung River, and thus provide an ideal example to explore the relationships between large fluvial systems and aeolian products. Although previous studies postulated that those aeolian products were originated from the Yarlung River, few empirical data actually exist to support this idea. We analysed the spatial pattern, sand transportation directions, and granulometric characteristics of the sand dunes to evaluate the potential influence of the Yarlung River on the aeolian processes. Comparison of the dune field distribution against channel width and longitudinal profile of the Yarlung River shows that sand dunes are clustered at the wide and flat segments of the river. Analyses of >4,600 sand dune orientations using Google Earth imagery show that the dunes located at the southern and northern sides of the Yarlung River demonstrate opposite sand transportation directions that generally point against the river. This suggests that the sand grains probably originated from the river. Grain size distributions from dune samples show unimodal or unimodal‐like patterns. This means that each sand dune field was dominantly fed by a simple transportation process rather than by compound processes from smaller‐level fluvial systems, which in turn implies that the Yarlung River was the most possible candidate for the provenance of these aeolian deposits. This study provides new constraints to demonstrate that the Yarlung River provides both accommodation space and sorted fluvial sand for the aeolian sand dunes along the river. [ABSTRACT FROM AUTHOR]

Desertification is a key environmental concern in arid and semi-arid regions. The sedimentological and geochemical characteristics of sediments are closely related to desertification processes, but the relationship between them is still unclear. This study aimed to identify the sedimentological and geochemical characteristics of different sediments in the Taklamakan Desert and to monitor changes in sediment composition as the intensity of desertification varied in the last decades. We examined the grain size, major, trace and rare earth elements of surface sediments collected from loess, sandy loess, fluvial sands, vegetated dunes and mobile dunes along the Keriya River in the Taklamakan Desert. Major element analysis found that loess had the highest degree of chemical weathering, while weathering of surface sediments on dunes (both mobile and vegetated ones) was relatively weak. Trace and rare earth element analysis found sediments were mainly derived from the West Kunlun and West Tianshan Mountains. This study also analyzed vegetation and wind data from 2000 to 2018 and found that the intensity of desertification processes weakened. The near-surface mean wind speed also decreased from 2000 to 2018, resulting in an increase in both the grain size of aeolian sediments on the surface of mobile dunes and the degree of chemical weathering. Additionally, this study confirmed that clay-sized components can be carried by high-altitude westerlies or formed by pedogenesis. With the strengthening of westerlies and the increase of chemical weathering, it is likely that more clay components will be added to the loess located on the northern slope of the Kunlun Mountains. This study demonstrates that the landscape evolution of the Keriya River in the Taklamakan Desert is primarily driven by fluvial processes, vegetation and wind dynamics, and that these processes may be affected by the intensity of desertification. [ABSTRACT FROM AUTHOR]

Irisin is a newly identified myokine that may be cancer-associated, and its impact on liver cancer is unclear. To understand the roles of irisin in liver cancer, we investigated its effect in HepG2 and SMCC7721 hepatocellular carcinoma cells, and the underlying mechanisms. We determined irisin levels in liver tissues and serum samples obtained from patients by using real-time polymerase chain reaction and enzyme-linked immunosorbent assay. Irisin levels in cancerous livers were significantly upregulated compared with those in control livers, but serum irisin levels remained unchanged. Additionally, we evaluated the effects of different concentrations of human recombinant modified and active (glycosylated) irisin (IM) or human recombinant nonmodified irisin (INM) on cell migration, proliferation, viability, and invasiveness. CCK8, transwell, and scratching assays demonstrated that irisin significantly increased cell proliferation, invasion, and migration through activation of the PI3K/AKT pathway. Irisin-induced cell proliferation, migration, and invasion were blocked by a PI3K inhibitor (LY294002). Irisin also decreased the cytotoxicity of doxorubicin in HepG2 cells. These data indicate that increased irisin levels may have protective roles in liver cancer cells through partial activation of the PI3K/AKT pathway, which may facilitate liver cancer progression and decrease the sensitivity to chemotherapy. [ABSTRACT FROM AUTHOR]

The Kubuqi Desert is the only active sand sea in the semiarid regions of northern China and occurs along the southern margin of the Yellow River. Little is known about the age and origin of this large (17,000 km 2 ) sand sea with a present annual precipitation of 200‐480 mm. Sand drift potentials indicated net capable winds for aeolian transport are from the northwest, though winds are stronger to north beyond the dune field than within the sand sea. Geomorphic and stratigraphic observations indicate that Holocene aeolian sand often drapes over bedrock and river terraces as a palimpsest landscape. Field investigations identified four stratigraphic sections with multiple aeolian sand units and palaeosols, with age control by optically stimulated luminescence (OSL) dating of quartz grains. Palaeosols are weakly developed, mostly accumulative A horizon with organic carbon content < 1% and reflect sand sheet deposition possibly in a steppe environment. Although sediments near river channels or former lakes might give old ages, the initial formation and age of the Kubuqi sand sea should be judged from the occurrence of the sandy palimpsest of the landscape that is OSL dated to the Holocene in general. The latest period of aeolian reactivation may be related to human activity associated with grazing and farming from lost cities in the Kubuqi Desert during the Han (206 B.C. – A.D. 220) and the Tang (A.D. 608 – 907) Dynasties. Also, variable discharge of the Yellow River with local diversions for irrigation and throughout the catchment resulted in possibly an increased supply of aeolian particles for dune field expansion in the past 2 ka. [ABSTRACT FROM AUTHOR]

Abstract: Identification of aeolian sand sources occurring in oases of desert environments is of great importance for understanding desertification processes and for developing strategies for sustainable development in arid regions. Combined with wind data and hierarchical cluster analysis, we analyzed the spatial characteristics of major and trace elements of sands sampled at the margins of the Minqin Oasis, northwestern China and its adjacent deserts (the Badain Jaran Desert and the Tengger Desert), with the purpose to identify the aeolian sand sources and their transport pathways in the region. The spatial distribution revealed by bivariate plots of Cr, Ni, Cr/V, Y/Ni, Al, V, Zr, Hf, Zr/Hf and ternary plots of major and trace elements showed that sands between the west (B – Badain Jaran Desert, BM – the dune belt between Badain Jaran and the Minqin Oasis and TNE – dune field located in the northeast margin of the Minqin Oasis) and southeast (TSW – dune field located in the southeast margin of the Minqin Oasis) sides of the oasis have different provenances, while the composition of sands in the Minqin Oasis (M) and in the dune field located in the south margin (TM) is associated with both. The variations in abundance of K, Rb, Ba and Sr were used as indicators of aeolian transport processes. Our results show that while aeolian sands from the Badain Jaran Desert can be transported over mountains and over long distances by northwest winds to the west sides of the Minqin Oasis, they cannot directly reach neither bypass the oasis to the east side. Our interpretation is that the oasis can act as an effective barrier to stop the migration of dune fields both in the Badain Jaran Desert and the Tengger Desert. However, the extensive occurrence of aeolian sands in the Minqin Oasis indicates that its role in preventing desert encroachment should not be overestimated. [Copyright &y& Elsevier]

Abstract: Sedimentary sequences occurring in desert dunes reflect changes in desert systems, and as such may contain signals useful for recognizing spatial and temporal changes of deserts and their response to regional or even global climate fluctuations. Geomorphological and palaeoenvironmental studies within the dune fields of the Asian middle-latitudes have provided some solid evidence for interpreting the history of these sand seas. Using the Hunshandake (Otindag) Sandy Land, a sandy area covered primarily by stabilized dunes and located in the semi-arid zone of eastern Inner Mongolia, China (Fig. 1), as an example, we studied the initiation and variation in the dune landscape in the eastern portion of the desert belt in northern China. On the basis of physical and biochemical indicators in the sediments and OSL chronology, we herein argue that this dune system in the middle latitudes of eastern Asia is much younger than previously assumed and that it has responded sensitively to climate change during the late Quaternary. Geological evidence from the Sandy Land suggests that most of the current dunes are of late Pleistocene or even Holocene age. Palaeosols intercalated in the aeolian sequences and their OSL chronology show that the climate of the Hunshandake was much wetter than today between 9.6 ka and 3 ka. This resulted in stabilization of the dunes in the eastern and central portions of the Sandy Land. Epochs of reworking or stabilization of the dunes are broadly consistent with the fluctuations in northern hemisphere solar radiation although with an obvious time lag. Because the increase rate of annual precipitation was not sufficient to fully stabilize the dunes in more arid part of the region, some active dunes persisted even during this long-lasting wetter epoch. We conclude that periods of Holocene dune stabilization due to palaeosol formation varied along the climate gradients across the various sandy lands of northern China, and in general it began earlier and lasted longer in the east than in the west. The general nature of the sandy lands and their counterparts in the western portion of the desert belt during the LGM and mid-Holocene climate optimum is discussed in comparison with their current states. [Copyright &y& Elsevier]