Effect of permafrost degradation on carbon sequestration of alpine ecosystems.

Permafrost degradation profoundly affects carbon storage in alpine ecosystems, and the response characteristics of carbon sequestration are likely to differ at the different stages of permafrost degradation. Furthermore, the sensitivity of different stages of permafrost degradation to climate change is likely to vary. However, related research is lacking so far on the Qinghai-Tibetan Plateau (QTP). To investigate these issues, the Shule River headwaters on the northeastern margin of the QTP was selected. We applied InVEST and Noah-MP land surface models in combination with remote sensing and field survey data to reveal the dynamics of different carbon (vegetation carbon, soil organic carbon (SOC), and ecosystem carbon) pools from 2001 to 2020. A space-for-time analysis was used to explore the response characteristics of carbon sequestration along a gradient of permafrost degradation, ranging from lightly degraded permafrost (H-SP) to severely degraded permafrost (U-EUP), and to analyze the sensitivity of the permafrost degradation gradient to climate change. Our results showed that: (1) the sensitivity of mean annual ground temperature (MAGT) to climatic variables in the U-EUP was stronger than that in the H-SP and S-TP, respectively; (2) rising MAGT led to permafrost degradation, but increasing annual precipitation promoted permafrost conservation; (3) vegetation carbon, SOC, and ecosystem carbon had similar spatial distribution patterns, with their storage decreasing from the mountain area to the valley; (4) alpine ecosystems acted as carbon sinks with the rate of 0.34 Mg‧ha-1‧a-1 during 2001-2020, of which vegetation carbon and SOC accumulations accounted for 10.65 % and 89.35 %, respectively; and (5) the effects of permafrost degradation from H-SP to U-EUP on carbon density changed from promotion to inhibition.

Priming effect stimulates carbon release from thawed permafrost.

Climate warming leads to widespread permafrost thaw with a fraction of the thawed permafrost carbon (C) being released as carbon dioxide (CO2 ), thus triggering a positive permafrost C-climate feedback. However, large uncertainty exists in the size of this model-projected feedback, partly owing to the limited understanding of permafrost CO2 release through the priming effect (i.e., the stimulation of soil organic matter decomposition by external C inputs) upon thaw. By combining permafrost sampling from 24 sites on the Tibetan Plateau and laboratory incubation, we detected an overall positive priming effect (an increase in soil C decomposition by up to 31%) upon permafrost thaw, which increased with permafrost C density (C storage per area). We then assessed the magnitude of thawed permafrost C under future climate scenarios by coupling increases in active layer thickness over half a century with spatial and vertical distributions of soil C density. The thawed C stocks in the top 3 m of soils from the present (2000-2015) to the future period (2061-2080) were estimated at 1.0 (95% confidence interval (CI): 0.8-1.2) and 1.3 (95% CI: 1.0-1.7) Pg (1 Pg = 1015 g) C under moderate and high Representative Concentration Pathway (RCP) scenarios 4.5 and 8.5, respectively. We further predicted permafrost priming effect potential (priming intensity under optimal conditions) based on the thawed C and the empirical relationship between the priming effect and permafrost C density. By the period 2061-2080, the regional priming potentials could be 8.8 (95% CI: 7.4-10.2) and 10.0 (95% CI: 8.3-11.6) Tg (1 Tg = 1012 g) C year-1 under the RCP 4.5 and RCP 8.5 scenarios, respectively. This large CO2 emission potential induced by the priming effect highlights the complex permafrost C dynamics upon thaw, potentially reinforcing permafrost C-climate feedback.

Spatiotemporal variations and driving factors for potential wind erosion on the Mongolian Plateau.

Wind erosion can cause desertification and sandstorms in arid and semiarid areas. However, quantitative studies of the dynamic changes in wind erosion over long time periods are relatively rare, and this knowledge gap hinders our understanding of desertification under the conditions of a changing climate. Here, we selected the Mongolian Plateau as the study area. Using the revised wind erosion equation (RWEQ) model, we assessed the spatial and temporal dynamics of wind erosion on the Mongolian Plateau from 1982 to 2018. Our results showed that the wind erosion intensity on the Mongolian Plateau increased from northeast to southwest. The annual mean wind erosion modulus was 46.5 t·ha-1 in 1982-2008, with a significant decline at a rate of -5.1 t·ha-1·10 yr-1. The intensity of wind erosion was the strongest in spring, followed by autumn and summer, and was weakest in winter. During 1982-2018, wind erosion showed a significant decreasing trend in all seasons except winter. The wind erosion contribution of spring to the total annual wind erosion significantly increased, while that of summer significantly decreased. These results can help decision-makers identify high-risk areas of soil erosion on the Mongolian Plateau and take effective measures to adapt to climate change.

Permafrost degradation is accelerating beneath the bottom of Yanhu Lake in the Hoh Xil, Qinghai-Tibet Plateau.

Lakes on the Qinghai-Tibet Plateau (QTP) have notably expanded over the past 20 years. Due to lake water level rise and lake area expansion, the permafrost surrounding these lakes is increasingly becoming submerged by lake water. However, the change process of submerged permafrost remains unclear, which is not conducive to further analyzing the environmental effects of permafrost change. Yanhu Lake, a tectonic lake on the QTP, has experienced significant expansion and water level rise. Field measurement results indicate that the water level of Yanhu Lake increased by 2.87 m per year on average from 2016 to 2019. Cold permafrost, developed in the lake basin, was partially submerged by lake water at the end of 2017. Based on the water level change and permafrost thermal regime, a numerical heat conduction permafrost model was employed to predict future changes in permafrost beneath the lake bottom. The simulated results indicate that the submerged permafrost would continuously degrade because of the significant thermal impact of lake water. By 2100, the maximum talik thicknesses could reach approximately 7, 12, 16, and 19 m under lake-bottom temperatures of +2.0, +4.0, +6.0, and +8.0 °C, respectively. Approximately 291 years would be required to completely melt 47 m of submerged permafrost under the lake-bottom temperature of +4 °C. Note that the permafrost table begins to melt earlier than does the permafrost base, and the decline in the permafrost table occurs relatively fast at first, but then the process is attenuated, after which the permafrost table again rapidly declines. Compared to climate warming, the degradation of the submerged permafrost beneath the lake bottom occurred more rapidly and notably.

Storage, patterns, and environmental controls of soil organic carbon stocks in the permafrost regions of the Northern Hemisphere.

Large stocks of soil organic carbon (SOC) accumulated in the Northern Hemisphere permafrost regions may be vulnerable to climatic warming, but global estimates of SOC distribution and magnitude in permafrost regions still have large uncertainties. Based on multiple high-resolution environmental variables and a compiled soil sample dataset (>3000 soil profiles), we used machine-learning methods to estimate the size and spatial distribution of SOC for the top 3 m soils in the Northern Hemisphere permafrost regions. We also identified key environmental predictors of SOC. The results showed that the SOC storage for the top 3 m soil was 1079 ± 174 Pg C across the Northern Hemisphere permafrost regions (20.8 × 106 km2), including 1057 ± 167 Pg C in the northern permafrost regions and 22 ± 7 Pg C in the Third Pole permafrost regions. The mean annual air temperature and NDVI are the main controlling factors for the spatial distribution of SOC stocks in the northern and the Third Pole permafrost regions. Our estimations were more accurate than the existing global SOC stock maps. The results improve our understanding of the regional and global permafrost carbon cycle and their feedback to the climate system.

Dynamic characteristics and synergistic effects of ecosystem services under climate change scenarios on the Qinghai-Tibet Plateau.

The Qinghai-Tibet Plateau (QTP) supplies many ecosystem services (ESs) that maintain local and global pan-Asian populations and ecosystems. The effects of climate change on ES provision in the QTP will have far-reaching impacts on the region and the many downstream ecosystems and countries that depend on ESs from the "Third Pole". This study undertook a systematic assessment of ES provision, trade-offs and synergies between four ESs (raw material provision, water yield, soil retention, and carbon storage) under future climate scenarios (representative concentration pathway). The results show that: (1) the total amount of the four ESs on the QTP is predicted to increase from 1980 to 2100 for three climate change scenarios. (2) The spatial pattern of ESs on the QTP will not change significantly in the future, and the grassland and forest ESs in the central and southern regions are predicted to increase significantly. (3) The synergistic interactions among ESs were generally consistent at three spatial scales (10 km (pixel), county and watershed scales), but with more significant synergistic effects at the watershed scale. This demonstrates the necessity for the examination of scale-dependent ES dynamics and interactions. This study will supply a reference for further research on long-term ES assessments, especially the dynamic ES changes and the spatial scale dependency of the ES interactions, and provide evidence-based strategies for formulating ecosystem management on the QTP under climate change.

Bi-allelic mutations in MOS cause female infertility characterized by preimplantation embryonic arrest.

STUDY QUESTION: Are mutations in MOS (MOS proto-oncogene, serine/threonine kinase) involved in early embryonic arrest in infertile women? SUMMARY ANSWER: We identified mutations in MOS that may cause human female infertility characterized by preimplantation embryonic arrest (PREMBA), and the effects of the mutations in human embryonic kidney 293T (HEK293T cells) and mouse oocytes provided evidence for a causal relation between MOS and female infertility. WHAT IS KNOWN ALREADY: MOS, an activator of mitogen-activated protein kinase, mediates germinal vesicle breakdown and metaphase II arrest. Female MOS knockout mice are viable but sterile. Thus, MOS seems to be an important part of the mammalian cell cycle mechanism that regulates female meiosis. STUDY DESIGN, SIZE, DURATION: Whole-exome sequencing, bioinformatics filtering analysis and genetic analysis were performed to identify two different biallelic mutations in MOS in two independent families. The infertile patients presenting with early embryonic arrest were recruited from October 2018 to June 2020. PARTICIPANTS/MATERIALS, SETTING, METHODS: The female patients diagnosed with primary infertility were recruited from the reproduction centres of local hospitals. Genomic DNA from the affected individuals, their family members and healthy controls was extracted from peripheral blood. We performed whole-exome sequencing in patients diagnosed with PREMBA. Functional effects of the mutations were investigated in HEK293T cells by western blotting and in mouse oocytes by microinjection and immunofluorescence. MAIN RESULTS AND THE ROLE OF CHANCE: We identified the homozygous missense mutation c.285C>A (p.(Asn95Lys)) and the compound heterozygous mutations c.467delG (p.(Gly156Alafs*18)) and c.956G>A (p.(Arg319His)) in MOS in two independent patients. The mutations c.285C>A (p.(Asn95Lys)) and c.467delG (p.(Gly156Alafs*18)) reduced the protein level of MOS, and all mutations reduced the ability of MOS to phosphorylate its downstream target, extracellular signal-regulated kinase1/2. In addition, the identified mutations reduced the capacity of exogenous human MOS to rescue the metaphase II exit phenotype, and the F-actin cytoskeleton of mouse oocytes was affected by the patient-derived mutations. LIMITATIONS, REASONS FOR CAUTION: Owing to the lack of in vivo data from patient oocytes, the exact molecular mechanism affected by MOS mutations and leading to PREMBA is still unknown and should be further investigated using knock-out or knock-in mice. WIDER IMPLICATIONS OF THE FINDINGS: We identified recessive mutations in MOS in two independent patients with the PREMBA phenotype. Our findings reveal the important role of MOS during human oocyte meiosis and embryonic development and suggest that mutations in MOS may be precise diagnostic markers for clinical genetic counselling. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by the National Natural Science Foundation of China (81725006, 81822019, 81771581, 81971450, 81971382,82001538 and 82071642), the project supported by the Shanghai Municipal Science and Technology Major Project (2017SHZDZX01), the Project of the Shanghai Municipal Science and Technology Commission (19JC1411001), the Natural Science Foundation of Shanghai (19ZR1444500 and 21ZR1404800), the Shuguang Program of the Shanghai Education Development Foundation and the Shanghai Municipal Education Commission (18SG03), the Foundation of the Shanghai Health and Family Planning Commission (20154Y0162), the Capacity Building Planning Program for Shanghai Women and Children's Health Service and the collaborative innovation centre project construction for Shanghai Women and Children's Health. The authors have no conflicts of interest to declare. TRIAL REGISTRATION NUMBER: N/A.

New permafrost is forming on the exposed bottom of Zonag Lake on the Qinghai-Tibet Plateau.

Most lakes on the Qinghai-Tibet Plateau have expanded in recent years. Zonag Lake, a critical habitat for Tibetan antelopes in the continuous permafrost zone, burst and overflowed after several years of expansion, resulting in a reduction of approximately 100 km2 in the lake area. Observations have revealed new permafrost is forming on the exposed bottom, accompanied by various periglacial landscapes. The permafrost aggradation on the exposed bottom is rapid, and the permafrost base reached 4.9 m, 5.4 m, and 5.7 m in the first three years, respectively. In this study, the future changes and influencing factors of recently formed permafrost are simulated using a one-dimensional finite element model of heat flow. The simulated results indicate that the permafrost on the exposed bottom is likely to continue to develop, appearing first quick back slow trend. Besides the surface temperature, the annual amplitude is also an important factor in affecting the aggradation of permafrost. The unidirectional permafrost aggradation in the study area is different from the bidirectional permafrost aggradation on the closed taliks around the Arctic. Additionally, snow cover and vegetation are two important factors influencing the future development of permafrost on the exposed lake bottom.

A bibliometric analysis of mountain ecosystem services, 2000-2019.

Research on mountain ecosystem services (MES) under the influence of climate change and human activities has gradually become the focus of academic attention in recent years. Here, this study analyzes the research hotspots and frontiers of this field based on metrics including main research forces, core journals and papers, research hotspots and topics by using the methods of bibliometrics and text mining. The results revealed the following: (1) the number of papers is increasing rapidly in recent years. From 2015 to 2019, 929 papers were published, with an average of 185 papers per year. But the average cited times of those papers is declining, dropped from 6.01 in 2016 to 4.2 in 2019. The USA, UK, and China rank the top three of the number of papers. Univ Maryland, Univ Oxford and Univ Wisconsin have the greatest influence, with an average of more than 77 citations per paper; (2) The most cited journals are PNAS, WETLANDS, ECOLOGY, AND SOCIETY, which are cited 191.54, 53.91, and 40.00 respectively. Most papers were published in OA journals including SUSTAINABILITY, WATER, Forests since 2017. Ten core papers undertaking knowledge transfer in this field have been identified; (3) analysis of the keywords found a new trend of integration of natural science and humanities. In two development stages of 2000-2014 and 2015-2019, the research hotspots mainly focused on mountain water resources, forest resources, land resources and the impact of climate change and human activities, and there are obvious differences and characteristics in different stages. The hotspot worthy of attention in the near future is the assessment of mountain ecosystem services capacity and value. This is the first comprehensive visualization and analysis of the research hotspots and trends of mountain ecosystem services.

A History of Endometriosis Is Associated With Decreased Peripheral NK Cytotoxicity and Increased Infiltration of Uterine CD68+ Macrophages.

Women with endometriosis may have a defective immune system. However, evidence of the immune responses of endometriosis patients with a history of endometriosis surgery is lacking, and the association between the location of endometriosis lesions and immune responses is unclear. This retrospective study included 117 females with reproductive failure and a history of endometriosis and 200 females with reproductive failure but without endometriosis to analyze their endometrial and peripheral immune responses. The results show that endometriosis was associated with decreased peripheral natural killer (NK) cytotoxicity and increased uterine macrophages. Peripheral NK cytotoxicity at effector-to-target ratios of 25:1 and 50:1 was significantly reduced in women with a history of endometriosis from that of the control group (26.6% versus 33.3% and 36.1% versus 43.3%, respectively, both P < 0.001). Furthermore, after further division of patients into three subgroups according to the location of endometriosis lesions, we observed that NK cytotoxicity in the endometriosis subgroups, especially the mixed endometriosis group, was strongly decreased from that of the controls (P = 0.001). The endometrial CD68+ macrophage proportion in the mixed endometriosis subgroup was higher than that in the control group (2.8% versus 2.1%, P = 0.043). In addition, the baseline estradiol (E2) level was weakly correlated with the percentage of endometrial macrophages (r = 0.251, P = 0.009), indicating a potential association among the endocrine system, endometrial immune environment, and endometriosis. This study indicated that peripheral NK cytotoxicity and endometrial immune cell profiles could be useful for diagnosing and treating endometriosis and endometriosis-related reproductive diseases.

Spatial and temporal change patterns of near-surface CO2 and CH4 concentrations in different permafrost regions on the Mongolian Plateau from 2010 to 2017.

Greenhouse gases (GHGs) released from permafrost regions may have a positive feedback to climate change, but there is much uncertainty about additional warming from the permafrost carbon cycle. One of the main reasons for this uncertainty is that the observation data of large-scale GHG concentrations are sparse, especially for areas with rapid permafrost degradation. We selected the Mongolian Plateau as the study area. We first analyzed the active layer thickness and ground temperature changes using borehole observations. Based on ground observation data, we assessed the applicability of Greenhouse Gases Observing Satellite (GOSAT) carbon dioxide (CO2) and methane (CH4) datasets. Finally, we analyzed the temporal and spatial changes in near-surface CO2 and CH4 concentrations from 2010 to 2017 and their patterns in different permafrost regions. The results showed that the Mongolian permafrost has been experiencing rapid degradation. The annual average near-surface CO2 concentration increased gradually between 2.19 ppmv/yr and 2.38 ppmv/yr, whereas the near-surface CH4 concentration increased significantly from 7.76 ppbv/yr to 8.49 ppbv/yr. There were significant seasonal variations in near-surface CO2 and CH4 concentrations for continuous, discontinuous, sporadic, and isolated permafrost zones. The continuous and discontinuous permafrost zones had lower near-surface CO2 and CH4 concentrations in summer and autumn, whereas sporadic and isolated permafrost zones had higher near-surface CO2 and CH4 concentrations in winter and spring. Our results indicated that climate warming led to rapid permafrost degradation, and carbon-based GHG concentrations also increased rapidly in Mongolia. Although, GHG concentrations increased at rates similar to the global average and many factors can account for their changes, GHG concentration in the permafrost regions merits more attention in the future because the spatiotemporal distribution has indicated a different driving force for regional warming.

Spatiotemporal variations and regional differences in air temperature in the permafrost regions in the Northern Hemisphere during 1980-2018.

Surface air temperature is an important factor for the permafrost thermal state in the Northern Hemisphere. It is therefore necessary to understand the variations and regional differences in air temperature to determine the interactions between permafrost degradation and climate change. In this study, we used observational data from the National Centers for Environmental Information, the China Meteorological Administration, and the World Data Centre for Meteorology to quantitatively analyze the variations and regional differences in air temperature from 1980 to 2018. The results demonstrated that the annual mean air temperatures were low in continuous permafrost regions and high in sporadic and isolated permafrost regions, with a significant warming rate of 0.371 ± 0.086 °C/decade. Air temperatures warmed the slowest during the winter and fastest during the spring, and no "warming hiatus" was observed in the permafrost regions of the Northern Hemisphere. The spatial patterns of freezing degree-days (FDDs) and thawing degree-days (TDDs) had different spatial characteristics. The decreasing rate of FDDs was -6.97 °C·days/year, while the increasing rate of TDDs was 6.4 °C·days/year. The air temperatures and warming trends had largely regional differences with respect to high latitude, transitional, and high altitude permafrost regions. Air temperature and its warming trend was the highest in high altitude regions. In addition, air temperature warming trends gradually decreased from the continuous permafrost zone to the island permafrost zone. The FDDs had a significant decreasing trend from the continuous permafrost zone to the island permafrost zone, whereas TDDs exhibited the opposite trend. The results indicate that the air temperature warming rate in the permafrost regions was approximately 2.0 times that of the global warming rate, and 1.3 times the global land warming rate from 1980 to 2018. These findings offer a perspective on the differences in permafrost and its thermal state across different regions under climate change.

Multi-omics reveals a relationship between endometrial amino acid metabolism and autophagy in women with recurrent miscarriage†.

Deterioration of the endometrial environment is an essential cause of recurrent miscarriage (RM). However, current studies in terms of endometrial amino acid metabolic characterization and autophagy are still inadequate. We tried to (1) identify the alternation in metabolite profiles in the RM endometrium; (2) investigate the expression of autophagy-related proteins in RM; and (3) elucidate the association between amino acid metabolism and autophagy in RM. Our results showed that glutamine metabolites were up-regulated in the endometrium of RM women. The levels of autophagy-associated proteins, LC3B, ATG12, and Beclin-1, were significantly higher in RM. Hemostasis, autophagy and IFNα signaling were the top three differentially activated signaling pathways between women with RM and normal pregnancy. Interestingly the expression of AMPK and GCN2 was significantly up-regulated in the endometrium of women with RM, and the same expression trend was also observed in the human endometrial stromal cells cultured in glutamine deprivation medium. Furthermore, inhibition of AMPK decreased the level of GCN2, indicating a positive correlation between GCN2 and AMPK. The expression of GCN2 was consistent with the expression of ATG12 and beclin-1; however, it was opposite to that of p62. Exposure to glutamine deprivation increased the level of LC3B, GCN2, ATG12, and beclin-1. Altogether, these findings suggested significant crosstalk between amino acid metabolism and autophagy. In summary, our data suggested that aberrant crosstalk between amino acid metabolism and autophagy may contribute to the impaired endometrial microenvironment of RM. Our study may provide new insight into the diagnosis of RM due to endometrial factors.

Risk assessment of potential thaw settlement hazard in the permafrost regions of Qinghai-Tibet Plateau.

Climate warming could exacerbate the occurrence of thaw settlement hazard in the permafrost regions of the Qinghai-Tibet Plateau (QTP), which would threaten the stability of engineering infrastructure in cold regions. The risk associated with permafrost settlement, valuable for the regional sustainable development, remains poorly assessed or understood on the QTP. In this study, three common Geo-hazard indices were used to assess the settlement risks in the permafrost regions of the QTP, including the settlement index, the risk zonation index, and the allowable bearing capacity index. However, large spatial differences existed in simulating the risk maps by using the abovementioned Geo-hazard indices. Hence, we developed a combined index (Ic) by integrating the three indices to reduce the uncertainty of the simulations. The results indicated that the ground ice is a critical factor for assessing the settlement risk in permafrost regions. We also applied the Ic to assess the settlement risk along the Qinghai-Tibet Railway (QTR). The proportion of low-risk area along the QTR would be the highest (45.38%) for the future periods 2061-2080 under Representative Concentration Pathway 4.5. The medium-risk area combined with the high-risk area would be accounted for more than 40%, which were located at the boundary of the present permafrost regions. Therefore, the corresponding adaptation measures should be taken to reduce the potential economic losses caused by the high-risk regions to the infrastructure. Overall, the results would present valuable references for engineering design, construction and maintenance, and provide insights for early warning and prevention of permafrost thaw settlement hazard on the QTP.

Reducing human activity promotes environmental restoration in arid and semi-arid regions: A case study in Northwest China.

Human activities have adversely impacted grassland net primary productivity (NPP) across the world, and quantitative estimations of the anthropogenic impacts on NPP (HNPP) can be helpful to improve environmental protection and climate adaptation measures. However, disentangling the effects of climate variability and human activities on NPP is problematic and requires the calculation of potential net primary productivity (PNPP). In this study, we assessed the anthropogenic impacts on NPP in the Shiyang River basin-a typical arid and semi-arid region. We used the seasonal changes in NPP to identify the grids that were not affected by human activity and then proposed a method to calculate PNPP based on the leaf area index (LAI). We estimated the actual net primary productivity (ANPP) using the Carnegie-Ames-Stanford Approach (CASA) model, and the HNPP was then calculated as the difference between ANPP and PNPP. Our results showed that this method for PNPP calculation was reliable. From 2001 to 2016, the positive (90.85 gC·m-2·a-1) and negative effects (-130.21 gC·m-2·a-1) of human activities on NPP accounted for 32.68% and 46.84% of the ANPP, respectively, and the overall average HNPP was -39.36 g C·m2·a-1. The implementation of ecological and environmental protection projects gradually mitigated the negative effects of human activity on NPP at a rate of 4.55 gC·m-2·a-1; however, negative HNPP values still occupied 55.39% of the entire region in 2016. In contrast with the prevailing views that climate change is the main factor accounting for vegetation recovery in arid and semi-arid regions, our results suggest that reducing human activities can significantly promote environmental restoration. The findings of this study suggest that policy makers and stakeholders can restore grassland ecosystems and promote environmental protection by reducing anthropogenic activities in arid and semi-arid regions.

Overexpression of lncRNA EPB41L4A-AS1 Induces Metabolic Reprogramming in Trophoblast Cells and Placenta Tissue of Miscarriage.

Long non-coding RNAs (lncRNAs) have been shown to be crucial regulators in numerous human diseases. However, little is known about their effects on early recurrent miscarriage (RM). Here we aimed to investigate the role of lncRNA EPB41L4A-AS1 on placental trophoblast cell metabolic reprogramming, which might be involved in the pathogenesis of RM. After microarray and GEO database analyses, we found that EPB41L4A-AS1 was significantly increased in early RM placental tissue, and this increase may relate to estradiol-mediated upregulation of PGC-1α. EPB41L4A-AS1 overexpression inhibits glycolysis but increases the dependence on fatty acid oxidation in mitochondrion metabolism and suppresses the Warburg effect, which is necessary for rapid growth of the placental villus, leading to miscarriage. Mechanistic analyses demonstrated that EPB41L4A-AS1 functions as a lncRNA in the regulation of VDAC1 and HIF-1α expression through enhancement of H3K4me3 levels in the promoters of VDAC1 and HIF1A-AS1, a natural antisense transcript (NAT) lncRNA of HIF-1α. Taken together, these findings demonstrate that aberrant expression of EPB41L4A-AS1 is involved in the etiology of early RM, and it may be a candidate diagnostic hallmark and a potential therapeutic target for early RM treatment.

Evaluation of two aneuploidy screening tests for chorionic villus samples: Multiplex ligation-dependent probe amplification and fluorescence in situ hybridization.

The vast majority of first-trimester pregnancy losses are the consequence of numerical aberrations in fetal chromosomes, which may involve nearly all chromosomes. Although commercial probes for all chromosomes are available for multiplex ligation-dependent probe amplification (MLPA) and fluorescence in situ hybridization (FISH) analyses, their use has rarely been reported for screening all 24 chromosomes for early fetal demise, especially by FISH. Here, we validated the ability of MLPA and FISH techniques as two low-cost aneuploidy screening methods for 24 chromosomes in 165 chorionic villus samples (CVSs). The results obtained by two methods were compared by the Chi-square test and the Kappa agreement test. Both methods gave conclusive results for all CVSs tested and showed highly consistent results (kappa = 0.890, p < 0.001). There was no statistically significant difference between the aneuploidy rate of the CVSs tested by the two methods (p = 0.180). Most of the samples showed fully concordant molecular karyotyping results (81.21%) between the two analytical methods, 10.91% had incompletely concordant results, and 7.88% had discordant results. The inconsistencies included segmental abnormalities, mosaicism, and polyploidy. Both assays used to screen 24 chromosomes were powerful techniques for detecting aneuploidy in CVSs. In terms of cost-effectiveness and diagnostic accuracy, the combination of subtelomeric (P036, P070) and centromeric (P181) MLPA assays is the better analytic strategy and follow-up analysis by FISH is recommended for MLPA-negative samples.

Spatial variations and controlling factors of ground ice isotopes in permafrost areas of the central Qinghai-Tibet Plateau.

Ground ice is a distinctive feature of permafrost, and its thawing under climate change can alter the regional hydrological and biogeochemical cycles. Spatial variations and determinants of ground ice isotopes are critical to understand subsurface water cycling during freeze-thaw process in the context of climate change, while they are not well known in permafrost region due to lack of field investigation. We examined spatial distributions and controlling factors of ground ice isotopes using data of 8 soil profiles surveyed in permafrost areas of the Qinghai-Tibet Plateau (QTP). The stable isotope values (δ2H and δ18O) of subsurface water on the QTP were higher than those in Arctic tundra ecosystem and East Siberian permafrost region. Isotopic values of water components differed each other, and varied significantly among the sampling sites. The spatial distribution of isotopes was complex. Isotopes generally decreased with depth within the soil profile, implying a general isotope depth gradient across different permafrost-affected areas. Water source, evaporative and freeze-out fractionation, and cryoturbation affect soil water isotopes. Correlation analyses showed that δ2H and δ18O in soil water positively related to air temperature and soil temperature, while negatively related to soil moisture, depth, active layer thickness, vegetation coverage, elevation, and precipitation. Elevation and soil depth mainly controlled spatial distributions of ground ice isotopes. The results could provide a new insight into soil moisture movement and cycling during freeze-thaw process in the permafrost region of the QTP, which is helpful to understand subsurface water cycle mechanism in the context of permafrost degradation.

Exploring the contribution of precipitation to water within the active layer during the thawing period in the permafrost regions of central Qinghai-Tibet Plateau by stable isotopic tracing.

Stable isotopic tracing has proven to be a useful tool for assessing surface water source dynamics and hydrological connectivity in permafrost regions. This study has investigated the contribution of precipitation to water within the active layer at three long-term observation sites, including Fenghuoshan (FHS), Hoh Xil (KKXL) and Wudaoliang (WDL), by using isotopic tracer technique and two-component mixing model. The results showed that precipitation was the predominant source for water within the active layer, permafrost and ground ice near permafrost table at the three sites. Precipitation in August was the predominant source for water within the active layer at FHS, and precipitation in September was the main source at KKXL and WDL. The variation of isotopic values at different levels indicated that the water sources within the active layer could vary as the depth increases. The evaporation fractionation of water within the active layer at WDL was noticeable at depths of 0-50 cm, and the evaporation intensity decrease gradually from late June to late September. The relationship of isotopic tracing values between precipitation and water within the active layer at depths of 0-50 cm becomes more significant as the amount of the recently-occurring precipitation increases. Moreover, the relatively higher d-excess in precipitation indicates that local recycled moisture has greater contribution to precipitation. The differences of d-excess in most water within the active layer, permafrost and ground ice near permafrost table revealed that there were isotopic fractionation when precipitation supplying to above-mentioned three water bodies. The precipitation event amounted to 8.1 mm at KKXL can exert 49% ±â€¯7.1% and 30.8% ±â€¯3.6% contribution to water within the active layer at depths of 0-10 cm and 10-20 cm, respectively. While the long-period contribution cannot be identified because of the impact of evaporation. The results would provide new insights into the contribution of precipitation to water within the active layer on the QTP, which is also helpful to improve process-based hydrological models in the permafrost regions.

Spatial distribution and changes of permafrost on the Qinghai-Tibet Plateau revealed by statistical models during the period of 1980 to 2010.

The Qinghai-Tibet Plateau (QTP), where is underlain by the highest and most extensive mid-altitude permafrost, is undergoing more dramatic climatic warming than its surrounding regions. Mapping the distribution of permafrost is of great importance to assess the impacts of permafrost changes on the regional climate system. In this study, we applied logistic regression model (LRM) and multi-criteria analysis (MCA) methods to map the decadal permafrost distribution on the QTP and to assess permafrost dynamics from the 1980s to 2000s. The occurrence of permafrost and its impacting factors (i.e., climatic and topographic elements) were constructed from in-situ field investigation-derived permafrost distribution patterns in 4 selected study regions. The validation results indicate that both LRM and MCA could efficiently map the permafrost distribution on the QTP. The areas of permafrost simulated by LRM and MCA are 1.23 × 106 km2 and 1.20 × 106 km2, respectively, between 2008 and 2012. The LRM and MCA modeling results revealed that permafrost area has significantly decreased at a rate of 0.066 × 106 km2 decade-1 over the past 30 years, and the decrease of permafrost area is accelerating. The sensitivity test results indicated that LRM did well in identifying the spatial distribution of permafrost and seasonally frozen ground, and MCA did well in reflecting permafrost dynamics. More parameters such as vegetation, soil property, and soil moisture are suggested to be integrated into the models to enhance the performance of both models.