| 1. |
- Xie, Yuan, et al.
(author)
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Key molecular alterations in endothelial cells in human glioblastoma uncovered through single-cell RNA sequencing
- 2021
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In: JCI Insight. - : American Society For Clinical Investigation. - 2379-3708. ; 6:15
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Journal article (peer-reviewed)abstract
- Passage of systemically delivered pharmacological agents into the brain is largely blocked by the blood-brain-barrier (BBB), an organotypic specialization of brain endothelial cells (ECs). Tumor vessels in glioblastoma (GBM), the most common malignant brain tumor in humans, are abnormally permeable, but this phenotype is heterogeneous and may differ between the tumor's center and invasive front. Here, through single-cell RNA sequencing (scRNA-seq) of freshly isolated ECs from human glioblastoma and paired tumor peripheral tissues, we have constructed a molecular atlas of human brain ECs providing unprecedented molecular insight into the heterogeneity of the human BBB and its molecular alteration in glioblastoma. We identified 5 distinct EC phenotypes representing different states of EC activation and BBB impairment, and associated with different anatomical locations within and around the tumor. This unique data resource provides key information for designing rational therapeutic regimens and optimizing drug delivery.
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| 2. |
- Zhu, RJ, et al.
(author)
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Mesenchymal stem cell treatment improves outcome of COVID-19 patients via multiple immunomodulatory mechanisms
- 2021
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In: Cell research. - : Springer Science and Business Media LLC. - 1748-7838 .- 1001-0602. ; 31:12, s. 1244-1262
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Journal article (peer-reviewed)abstract
- The infusion of coronavirus disease 2019 (COVID-19) patients with mesenchymal stem cells (MSCs) potentially improves clinical symptoms, but the underlying mechanism remains unclear. We conducted a randomized, single-blind, placebo-controlled (29 patients/group) phase II clinical trial to validate previous findings and explore the potential mechanisms. Patients treated with umbilical cord-derived MSCs exhibited a shorter hospital stay (P = 0.0198) and less time required for symptoms remission (P = 0.0194) than those who received placebo. Based on chest images, both severe and critical patients treated with MSCs showed improvement by day 7 (P = 0.0099) and day 21 (P = 0.0084). MSC-treated patients had fewer adverse events. MSC infusion reduced the levels of C-reactive protein, proinflammatory cytokines, and neutrophil extracellular traps (NETs) and promoted the maintenance of SARS-CoV-2-specific antibodies. To explore how MSCs modulate the immune system, we employed single-cell RNA sequencing analysis on peripheral blood. Our analysis identified a novel subpopulation of VNN2+ hematopoietic stem/progenitor-like (HSPC-like) cells expressing CSF3R and PTPRE that were mobilized following MSC infusion. Genes encoding chemotaxis factors — CX3CR1 and L-selectin — were upregulated in various immune cells. MSC treatment also regulated B cell subsets and increased the expression of costimulatory CD28 in T cells in vivo and in vitro. In addition, an in vivo mouse study confirmed that MSCs suppressed NET release and reduced venous thrombosis by upregulating kindlin-3 signaling. Together, our results underscore the role of MSCs in improving COVID-19 patient outcomes via maintenance of immune homeostasis.
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| 3. |
- Abbafati, Cristiana, et al.
(author)
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- 2020
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Journal article (peer-reviewed)
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| 4. |
- Cao, Hong Min, et al.
(author)
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A long-lived compact jet in the black hole X-ray binary candidate AT2019wey
- 2022
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In: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 657
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Journal article (peer-reviewed)abstract
- AT2019wey is a transient discovered by the Asteroid Terrestrial-impact Last Alert System survey in December of 2019. Follow-up optical, radio, and X-ray observations led to classification of this source as a Galactic black hole X-ray binary candidate. We carried out one-epoch 6.7 GHz European Very Long Baseline Interferometry Network and two-epoch multi-frequency (1.6, 4.5, 6.7 GHz) Very Long Baseline Array observations within a year after its discovery. These observations reveal a fading and flat-spectrum radio source with no discernible motion. These features suggest the detection of a compact jet. The source appears resolved at milliarcsecond scales, and the source angular size versus frequency trend is consistent with scatter broadening. This allows us to constrain the lower limit of the source distance to 6 kpc if the scattering medium is in a Galactic spiral arm. For a source location at greater than 3 kpc, the estimated upper limit of the peculiar velocity suggests the asymmetric natal kick may have occurred during the black hole formation stage.
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| 5. |
- Davies, Stuart J., et al.
(author)
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ForestGEO: Understanding forest diversity and dynamics through a global observatory network
- 2021
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In: Biological Conservation. - : Elsevier BV. - 0006-3207. ; 253
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Journal article (peer-reviewed)abstract
- ForestGEO is a network of scientists and long-term forest dynamics plots (FDPs) spanning the Earth's major forest types. ForestGEO's mission is to advance understanding of the diversity and dynamics of forests and to strengthen global capacity for forest science research. ForestGEO is unique among forest plot networks in its large-scale plot dimensions, censusing of all stems ≥1 cm in diameter, inclusion of tropical, temperate and boreal forests, and investigation of additional biotic (e.g., arthropods) and abiotic (e.g., soils) drivers, which together provide a holistic view of forest functioning. The 71 FDPs in 27 countries include approximately 7.33 million living trees and about 12,000 species, representing 20% of the world's known tree diversity. With >1300 published papers, ForestGEO researchers have made significant contributions in two fundamental areas: species coexistence and diversity, and ecosystem functioning. Specifically, defining the major biotic and abiotic controls on the distribution and coexistence of species and functional types and on variation in species' demography has led to improved understanding of how the multiple dimensions of forest diversity are structured across space and time and how this diversity relates to the processes controlling the role of forests in the Earth system. Nevertheless, knowledge gaps remain that impede our ability to predict how forest diversity and function will respond to climate change and other stressors. Meeting these global research challenges requires major advances in standardizing taxonomy of tropical species, resolving the main drivers of forest dynamics, and integrating plot-based ground and remote sensing observations to scale up estimates of forest diversity and function, coupled with improved predictive models. However, they cannot be met without greater financial commitment to sustain the long-term research of ForestGEO and other forest plot networks, greatly expanded scientific capacity across the world's forested nations, and increased collaboration and integration among research networks and disciplines addressing forest science.
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| 6. |
- GUAN, WEN, et al.
(author)
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Frequency tuning behaviour of terahertz quantum cascade lasers revealed by a laser beating scheme
- 2021
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In: Optics Express. - 1094-4087 .- 1094-4087. ; 29:14, s. 21269-21279
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Journal article (peer-reviewed)abstract
- In the terahertz frequency range, the commercialized spectrometers, such as the Fourier transform infrared and time domain spectroscopies, show spectral resolutions between a hundred megahertz and a few gigahertz. Therefore, the high precision frequency tuning ability of terahertz lasers cannot be revealed by these traditional spectroscopic techniques. In this work, we demonstrate a laser beating experiment to investigate the frequency tuning characteristics of terahertz quantum cascade lasers (QCLs) induced by temperature or drive current. Two terahertz QCLs emitting around 4.2 THz with identical active regions and laser dimensions (150 μm wide and 6 mm long) are employed in the beating experiment. One laser is operated as a frequency comb and the other one is driven at a lower current to emit a single frequency. To measure the beating signal, the single mode laser is used as a fast detector (laser self-detection). The laser beating scheme allows the high precision measurement of the frequency tuning of the single mode terahertz QCL. The experimental results show that in the investigated temperature and current ranges, the frequency tuning coefficients of the terahertz QCL are 6.1 MHz/0.1 K (temperature tuning) and 2.7 MHz/mA (current tuning) that cannot be revealed by a traditional terahertz spectrometer. The laser beating technique shows potential abilities in high precision linewidth measurements of narrow absorption lines and multi-channel terahertz communications.
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| 7. |
- Jiang, Pengfei, et al.
(author)
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VLBI detection of the AE Aqr twin, LAMOST J024048.51+195226.9
- 2024
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In: Monthly Notices of the Royal Astronomical Society: Letters. - 1745-3925 .- 1745-3933. ; 528:1, s. L112-L116
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Journal article (peer-reviewed)abstract
- LAMOST J024048.51+195226.9 (J0240+1952) was recently identified as the second AE Aquarii (AE Aqr)-type cataclysmic variable, possessing the fastest known rotating white dwarf. We performed a Very Long Baseline Interferometry (VLBI) observation of J0240+1952 utilizing the European VLBI Network at 1.7 GHz, to obtain the first view of the radio morphology on mas scale. Our high-resolution VLBI image clearly shows that the radio emission is compact on mas scale (≲2 AU), with no evidence for a radio jet or extended emission. The compact radio source has an average flux density of ∼0.37 mJy, and its brightness temperature is given at ∼2.3 × 107 K, confirming a non-thermal origin. The emission exhibits irregular variations on a time-scale of tens of minutes, similar to the radio flares seen in AE Aqr. The measured VLBI position of J0240+1952 is consistent with that derived from Gaia. Our results favour the model in which the radio emission is attributed to a superposition of synchrotron radiation from expanding magnetized blobs of this system.
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| 8. |
- Luo, Qingyong, et al.
(author)
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Graptolites as fossil geo-thermometers and source material of hydrocarbons: An overview of four decades of progress
- 2020
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In: Earth-Science Reviews. - : Elsevier BV. - 0012-8252 .- 1872-6828. ; 200
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Journal article (peer-reviewed)abstract
- The thermal maturity of lower Paleozoic graptolite-bearing marine sediments, which host many hydrocarbon deposits worldwide, has long been difficult to determine due to the absence of wood-derived vitrinite particles for conventional vitrinite reflectance. In 1976, graptolite reflectance was introduced as a new indicator for organic maturity of these deposits and has been used since in many regional studies. The majority of these studies, however, were done on a limited sample set and a limited range of thermal maturity, which resulted in a number of controversial views concerning the usefulness of graptolite reflectance as an alternative paleothermal indicator and its correlation with vitrinite reflectance through various proxies. In this paper, we review previous studies and combine those analyses with new data to assess the physical and chemical characteristics of graptolite periderm with increasing thermal maturity. We conclude that graptolite random reflectance (GRor) is a better parameter for the thermal maturity assessment than graptolite maximum reflectance (GRomax) due to the better quality of available data. Combining published data with results of our study of both natural and heat-treated graptolites and vitrinite, we present a new correlation between GRor and equivalent vitrinite reflectance (EqVRo), as EqVRo = 0.99GRor + 0.08. Chemical composition of graptolite periderm is similar to vitrinite; graptolites are mainly kerogen Type II-III, are gas prone and have a substantial hydrocarbon potential. Lower Paleozoic graptolite-bearing organic-rich sediments are important shale gas source rocks and reservoirs globally and make a significant contribution to worldwide petroleum reserves
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| 9. |
- Luo, Qingyong, et al.
(author)
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Thermal evolution behavior of the organic matter and a ray of light on the origin of vitrinite-like maceral in the Mesoproterozoic and Lower Cambrian black shales: Insights from artificial maturation
- 2021
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In: International Journal of Coal Geology. - : Elsevier BV. - 0166-5162 .- 1872-7840. ; 244, s. 103813-103813
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Journal article (peer-reviewed)abstract
- The overmature Precambrian to Lower Paleozoic marine shales from China contain relatively simple organic matter (OM) composition, which is dominated by in-source solid bitumen (i.e., solid bitumen in the hydrocarbon source rocks). The thermal evolution behavior of the original OM and the determination of thermal maturity in the Precambrian to Cambrian marine shales have been challenging for decades. The vitrinite-like maceral (VLM) is widely present in these marine shales, and its origin is still unknown. To address these issues, the immature Proterozoic Xiamaling shales from China and the immature Cambrian Alum shales from Sweden, and a Chinese immature Carboniferous coal were heat-treated at temperature range of 300 ◦C to 550 ◦C. The carbonized residue of the artificially matured samples was examined for their morphological and reflectance variation, and the results were compared with data on the other overmature natural shales from China and Sweden. OM components are similar in the Xiamaling and Alum immature oil shales, consisting of filamentous algae, matrix bituminite, bituminite, VLM and liptodetrinite, and rare thucholites are present in the Xiamaling shales. The algal-derived OM decomposed gradually due to hydrocarbon generation at 300–350 ◦C. OM is mainly composed of the in-source solid bitumen in the artificially heated shales after 350 ◦C, similar to the overmature Precambrian to Cambrian natural shales, and the in-source solid bitumen gradually loses its mass with increasing thermal maturity. The in-source solid bitumen is derived from the thermal cracking of the retained oil or the direct conversion of algal-derived liptinite macerals (e.g., the bituminite) or their mixture. VLM in the Xiamaling oil shales can not be observed after 350 ◦C, but VLM is still present in the Alum oil shales. It can be inferred that there is a different source of VLM in these shales, and VLM in the Xiamaling oil shales contains more volatile material. The VLM in the Xiamaling shales may be biodegradation products of liptinites under anoxic environments. The origin of VLM in the Cambrian Alum shales requires further study to be verified, although it is certain that graptolites are not its sources. The reflectance of in-source solid bitumen (SBRo) increases with heat-treated temperature in both the Xiamaling shales and the Alum shales, but at different rates, which may be due to the difference of the original kerogen composition in these shales. VLM reflectance (VLMRo) and SBRo in sections perpendicular to bedding can be used to determine the maturation level of the Precambrian-Cambrian sediments. Their relation to equivalent vitrinite reflectance (EqVRo) can be expressed by the following equations: EqVRo = 1.07 × VLMRo – 0.18, EqVRo = 0.87 × SBRo + 0.25 (in the Precambrian sediments) and EqVRo = 1.15 × SBRo + 0.01 (in the Cambrian sediments).
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| 10. |
- Needham, Jessica F., et al.
(author)
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Demographic composition, not demographic diversity, predicts biomass and turnover across temperate and tropical forests
- 2022
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In: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 28, s. 2895-2909
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Journal article (peer-reviewed)abstract
- The growth and survival of individual trees determine the physical structure of a forest with important consequences for forest function. However, given the diversity of tree species and forest biomes, quantifying the multitude of demographic strategies within and across forests and the way that they translate into forest structure and function remains a significant challenge. Here, we quantify the demographic rates of 1961 tree species from temperate and tropical forests and evaluate how demographic diversity (DD) and demographic composition (DC) differ across forests, and how these differences in demography relate to species richness, aboveground biomass (AGB), and carbon residence time. We find wide variation in DD and DC across forest plots, patterns that are not explained by species richness or climate variables alone. There is no evidence that DD has an effect on either AGB or carbon residence time. Rather, the DC of forests, specifically the relative abundance of large statured species, predicted both biomass and carbon residence time. Our results demonstrate the distinct DCs of globally distributed forests, reflecting biogeography, recent history, and current plot conditions. Linking the DC of forests to resilience or vulnerability to climate change, will improve the precision and accuracy of predictions of future forest composition, structure, and function.
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