| 1. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 2. |
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| 3. |
- Klionsky, Daniel J., et al.
(författare)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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Forskningsöversikt (refereegranskat)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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| 4. |
- Chu, Ming, et al.
(författare)
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Accurate capacitance-voltage characterization of organic thin films with current injection*
- 2021
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Ingår i: Chinese Physics B. - : IOP PUBLISHING LTD. - 1674-1056. ; 30:8
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Tidskriftsartikel (refereegranskat)abstract
- To deal with the invalidation of commonly employed series model and parallel model in capacitance-voltage (C-V) characterization of organic thin films when current injection is significant, a three-element equivalent circuit model is proposed. On this basis, the expression of real capacitance in consideration of current injection is theoretically derived by small-signal analysis method. The validity of the proposed equivalent circuit and theoretical expression are verified by a simulating circuit consisting of a capacitor, a diode, and a resistor. Moreover, the accurate C-V characteristic of an organic thin film device is obtained via theoretical correction of the experimental measuring result, and the real capacitance is 35.7% higher than the directly measured capacitance at 5-V bias in the parallel mode. This work strongly demonstrates the necessity to consider current injection in C-V measurement and provides a strategy for accurate C-V characterization experimentally.
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| 5. |
- Büntgen, Ulf, et al.
(författare)
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Global wood anatomical perspective on the onset of the Late Antique Little Ice Age (LALIA) in the mid-6th century CE
- 2022
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Ingår i: Science Bulletin. - : Elsevier BV. - 2095-9273. ; 67:22, s. 2336-2344
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Tidskriftsartikel (refereegranskat)abstract
- Linked to major volcanic eruptions around 536 and 540 CE, the onset of the Late Antique Little Ice Age has been described as the coldest period of the past two millennia. The exact timing and spatial extent of this exceptional cold phase are, however, still under debate because of the limited resolution and geographical distribution of the available proxy archives. Here, we use 106 wood anatomical thin sections from 23 forest sites and 20 tree species in both hemispheres to search for cell-level fingerprints of ephemeral summer cooling between 530 and 550 CE. After cross-dating and double-staining, we identified 89 Blue Rings (lack of cell wall lignification), nine Frost Rings (cell deformation and collapse), and 93 Light Rings (reduced cell wall thickening) in the Northern Hemisphere. Our network reveals evidence for the strongest temperature depression between mid-July and early-August 536 CE across North America and Eurasia, whereas more localised cold spells occurred in the summers of 532, 540–43, and 548 CE. The lack of anatomical signatures in the austral trees suggests limited incursion of stratospheric volcanic aerosol into the Southern Hemisphere extra-tropics, that any forcing was mitigated by atmosphere-ocean dynamical responses and/or concentrated outside the growing season, or a combination of factors. Our findings demonstrate the advantage of wood anatomical investigations over traditional dendrochronological measurements, provide a benchmark for Earth system models, support cross-disciplinary studies into the entanglements of climate and history, and question the relevance of global climate averages.
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| 6. |
- Chen, Shao-Chun, et al.
(författare)
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First nationwide study regarding ceftriaxone resistance and molecular epidemiology of Neisseria gonorrhoeae in China
- 2016
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Ingår i: Journal of Antimicrobial Chemotherapy. - : Oxford University Press. - 0305-7453 .- 1460-2091. ; 71:1, s. 92-99
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Antimicrobial resistance (AMR) in Neisseria gonorrhoeae is a major public health concern worldwide. This is the first nationwide study, performed within the China Gonococcal Antimicrobial Susceptibility Programme (China-GASP), regarding AMR, including ceftriaxone genetic resistance determinants, and molecular epidemiology of gonococci in China.Methods: Gonococcal isolates (naEuroS=aEuroS1257) from consecutive patients were collected at 11 sentinel sites distributed across China during 2012-13. Susceptibility to ceftriaxone, spectinomycin, ciprofloxacin and tetracycline was determined using the agar dilution method. Ceftriaxone resistance determinants penA and penB were examined using sequencing. N. gonorrhoeae multiantigen sequence typing (NG-MAST) was performed for molecular epidemiology.Results: Among isolates, 0.2% were resistant to spectinomycin, 4.4% to ceftriaxone, 42.9% to tetracyclines (high-level resistance) and 99.8% to ciprofloxacin. Among 890 sequenced isolates, 16 (1.8%) possessed a penA mosaic allele; 4 of these isolates belonged to the MDR internationally spread NG-MAST genogroup G1407 (first description in China). Non-mosaic penA alleles with an A501T mutation and an A102D alteration in porB1b were statistically associated with decreased susceptibility/resistance to ceftriaxone. NG-MAST G10339, G1424 and G1053 were associated with decreased susceptibility/resistance to ceftriaxone.Conclusions: In China, ceftriaxone and spectinomycin can continue to be recommended for gonorrhoea treatment, with the possible exception of Hainan and Sichuan provinces where ceftriaxone resistance exceeded 5% and AMR surveillance needs to be strengthened. Molecular approaches including genotyping and AMR determinant analysis can be valuable to supplement and enhance conventional surveillance of gonococcal AMR in China.
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| 7. |
- Chen, Shao-Chun, et al.
(författare)
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Prevalence and Molecular Epidemiological Typing of Penicillinase-Producing Neisseria gonorrhoeae and Their bla(TEM-135) Gene Variants in Nanjing, China
- 2013
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Ingår i: Sexually Transmitted Diseases. - 0148-5717 .- 1537-4521. ; 40:11, s. 872-876
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Tidskriftsartikel (refereegranskat)abstract
- Background: This study aimed to investigate the prevalence of penicillinase-producing Neisseria gonorrhoeae (PPNG) and their bla(TEM-135) gene variant in 2007 and 2012 in Nanjing, China. In addition, molecular epidemiological typing of all isolates was performed to elucidate the genetic relationships of the PPNG strains. Methods: A total of 199 and 77 N. gonorrhoeae isolates were collected at the National Center for STD Control in 2007 and 2012, respectively. Nitrocefin tests were performed to identify PPNG. Mismatch amplification mutation assay was used to identify bla(TEM-135). All isolates were genotyped using N. gonorrhoeae multiantigen sequence typing (NG-MAST), and additionally, porB-based phylogenetic analysis was performed for the PPNG isolates. Results: The total prevalence of PPNG isolates was 41% (114/276) and 58% (66/114) of these PPNG isolates possessed bla(TEM-135). In 2007, 45% (90/199) produced beta-lactamase, and of those PPNG, 58% (52/90) possessed bla(TEM-135). In 2012, 31% (24/77) were PPNG, and 58% (14/24) of those isolates contained bla(TEM-135). There were 162 NG-MAST STs among the 276 isolates, and 89 of those were novel STs. A strong association between specific NG-MAST STs and bla(TEM-135) was found, and the porB-based phylogenetic analysis showed a distant evolutionary relationship between isolates in 2007 and isolates in 2012. Conclusions: A high prevalence of PPNG and bla(TEM-135) was found in Nanjing, China. bla(TEM-135) might be a precursor in the evolution into an extended-spectrum beta-lactamase that can degrade ceftriaxone, which stresses the need to continuously monitor PPNG, bla(TEM-135), and additional evolving bla(TEM) gene variants.
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| 8. |
- He, Minhui, et al.
(författare)
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Recent advances in dendroclimatology in China
- 2019
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Ingår i: Earth-Science Reviews. - : Elsevier BV. - 0012-8252 .- 1872-6828. ; 194, s. 521-535
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Forskningsöversikt (refereegranskat)abstract
- Considerable progress has been made in dendroclimatological research in China during the period 2000-2017, including a significant increase in the spatial coverage of tree-ring chronologies developed for paleoclimatic research. New tree-ring sampling sites have been established across the Tibetan Plateau, as well as the north-eastern and sub-tropical eastern parts of China. Most of the studies use coniferous trees, although different plant functional types (e.g., broadleaf species and shrubs) have also been increasingly investigated. Tree-ring chronologies longer than 600 years, however, are mostly found on the Tibetan Plateau, with the longest one extending back to 2637 BCE (before Common Era). Most tree-ring records in the eastern parts of China are < 400 years long. Tree-ring width is the most commonly studied parameter, although stable isotope ratios and wood density data have also been obtained for specific sites. Stable oxygen isotope data frequently shares a common hydroclimate signal, whereas the climate or environmental signals remain inconsistent for the few available stable carbon isotope records. In general, tree-ring width-based temperature reconstructions originate from higher elevation sites (i.e., treeline) compared to hydroclimate reconstructions. Precipitation or drought reconstructions are mainly obtained from regions with an annual precipitation of < 800 mm. Most of the tree-ring reconstructions are based on individual site or local-scale chronologies, although a limited number of regional-scale and field reconstructions have been produced. The most prominent identified characteristics of the recent advances in dendroclimatological research for China have manifested in aspects such as an expanded network of sampling sites, improved climate reconstruction methodology, and improved uncertainty estimations in the latter. Furthermore, the traditional statistical-based tree growth climate relationships have been supplemented by monitoring and modeling approaches. Based on the progress from 2000 to 2017, and on the research potential of the country in this field, we expect additional widening of the dendroclimatological investigations in China during the coming years.
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| 9. |
- Kyrpides, Nikos C, et al.
(författare)
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Genomic encyclopedia of bacteria and archaea: sequencing a myriad of type strains.
- 2014
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Ingår i: PLoS biology. - : Public Library of Science (PLoS). - 1545-7885. ; 12:8
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Tidskriftsartikel (refereegranskat)abstract
- Microbes hold the key to life. They hold the secrets to our past (as the descendants of the earliest forms of life) and the prospects for our future (as we mine their genes for solutions to some of the planet's most pressing problems, from global warming to antibiotic resistance). However, the piecemeal approach that has defined efforts to study microbial genetic diversity for over 20 years and in over 30,000 genome projects risks squandering that promise. These efforts have covered less than 20% of the diversity of the cultured archaeal and bacterial species, which represent just 15% of the overall known prokaryotic diversity. Here we call for the funding of a systematic effort to produce a comprehensive genomic catalog of all cultured Bacteria and Archaea by sequencing, where available, the type strain of each species with a validly published name (currently∼11,000). This effort will provide an unprecedented level of coverage of our planet's genetic diversity, allow for the large-scale discovery of novel genes and functions, and lead to an improved understanding of microbial evolution and function in the environment.
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| 10. |
- Li, Shenpan, et al.
(författare)
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Hepatic injury and ileitis associated with gut microbiota dysbiosis in mice upon F–53B exposure
- 2024
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Ingår i: Environmental Research. - : Elsevier. - 0013-9351 .- 1096-0953. ; 248
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Tidskriftsartikel (refereegranskat)abstract
- Chlorinated polyfluorinated ether sulfonate (F–53B), a substitute of perfluorooctane sulfonic acid (PFOS), has attracted significant attention for its link to hepatotoxicity and enterotoxicity. Nevertheless, the underlying mechanisms of F–53B-induced enterohepatic toxicity remain incompletely understood. This study aimed to explore the role of F–53B exposure on enterohepatic injury based on the gut microbiota, pathological and molecular analysis in mice. Here, we exposed C57BL/6 mice to F–53B (0, 4, 40, and 400 μg/L) for 28 days. Our findings revealed a significant accumulation of F–53B in the liver, followed by small intestines, and feces. In addition, F–53B induced pathological collagen fiber deposition and lipoid degeneration, up-regulated the expression of fatty acid β-oxidation-related genes (PPARα and PPARγ, etc), while simultaneously down-regulating pro-inflammatory genes (Nlrp3, IL-1β, and Mcp1) in the liver. Meanwhile, F–53B induced ileal mucosal barrier damage, and an up-regulation of pro-inflammatory genes and mucosal barrier-related genes (Muc1, Muc2, Claudin1, Occludin, Mct1, and ZO-1) in the ileum. Importantly, F–53B distinctly altered gut microbiota compositions by increasing the abundance of Akkermansia and decreasing the abundance of Prevotellaceae_NK3B31_group in the feces. F–53B-altered microbiota compositions were significantly associated with genes related to fatty acid β-oxidation, inflammation, and mucosal barrier. In summary, our results demonstrate that F–53B is capable of inducing hepatic injury, ileitis, and gut microbiota dysbiosis in mice, and the gut microbiota dysbiosis may play an important role in the F–53B-induced enterohepatic toxicity.
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| 11. |
- Nah, Wan Jun, et al.
(författare)
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Rethinking Long-Tailed Visual Recognition with Dynamic Probability Smoothing and Frequency Weighted Focusing
- 2023
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Ingår i: Proceedings - International Conference on Image Processing, ICIP. - 1522-4880. ; , s. 435-439
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Konferensbidrag (refereegranskat)abstract
- Deep learning models trained on long-tailed (LT) datasets often exhibit bias towards head classes with high frequency. This paper highlights the limitations of existing solutions that combine class- and instance-level re-weighting loss in a naive manner. Specifically, we demonstrate that such solutions result in overfitting the training set, significantly impacting the rare classes. To address this issue, we propose a novel loss function that dynamically reduces the influence of outliers and assigns class-dependent focusing parameters. We also introduce a new long-tailed dataset, ICText-LT, featuring various image qualities and greater realism than artificially sampled datasets. Our method has proven effective, outperforming existing methods through superior quantitative results on CIFAR-LT, Tiny ImageNet-LT, and our new ICText-LT datasets. The source code and new dataset are available at \url{https://github.com/nwjun/FFDS-Loss}
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| 12. |
- Ng, Chun Chet, et al.
(författare)
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When IC meets text: Towards a rich annotated integrated circuit text dataset
- 2024
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Ingår i: Pattern Recognition. - 0031-3203. ; 147
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Tidskriftsartikel (refereegranskat)abstract
- Automated Optical Inspection (AOI) is a process that uses cameras to autonomously scan printed circuit boards for quality control. Text is often printed on chip components, and it is crucial that this text is correctly recognized during AOI, as it contains valuable information. In this paper, we introduce \textit{ICText}, the largest dataset for text detection and recognition on integrated circuits. Uniquely, it includes labels for character quality attributes such as low contrast, blurry, and broken. While loss-reweighting and Curriculum Learning (CL) have been proposed to improve object detector performance by balancing positive and negative samples and gradually training the model from easy to hard samples, these methods have had limited success with one-stage object detectors commonly used in industry. To address this, we propose Attribute-Guided Curriculum Learning (AGCL), which leverages the labeled character quality attributes in \textit{ICText}. Our extensive experiments demonstrate that AGCL can be applied to different detectors in a plug-and-play fashion to achieve higher Average Precision (AP), significantly outperforming existing methods on \textit{ICText} without any additional computational overhead during inference. Furthermore, we show that AGCL is also effective on the generic object detection dataset Pascal VOC. Our code and dataset will be publicly available at \href{https://github.com/chunchet-ng/ICText-AGCL}{https://github.com/chunchet-ng/ICText-AGCL}.
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| 13. |
- Qin, Ruiping, et al.
(författare)
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A Planar Copolymer for High Efficiency Polymer Solar Cells
- 2009
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Ingår i: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 131:41, s. 14612-
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Tidskriftsartikel (refereegranskat)abstract
- An alternating copolymer, poly(2-(5-(5,6-bis(octyloxy)-4-(thiophen-2-yl)benzo[c][1,2,5]thiadiazol-7-yl)thiophen-2-yl)-9-octyt-9H-carbazole) (HXS-1), was designed, synthesized, and used as the donor material for high efficiency polymer solar cells. The close packing of the polymer chains in the solid state was confirmed by XRD. A J(sc) of 9.6 mA/cm(2), a V-proportional to of 0.81 V, an FF of 0.69, and a PCE of 5.4% were achieved with HXS-1 and [6,6]-phenyl C-71-butyric acid methyl ester (PC71BM) as a bulk heterojunction active layer spin-coated from a solvent mixture of 1,2-dichlorobenzene and 1,8-diodooctane (97.5:2.5) under air mass 1.5 global (AM 1.5 G) irradiation of 100 mW/cm(2).
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| 14. |
- Quintana, Crisanto, et al.
(författare)
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A high speed retroreflective free space optics links with UAV
- 2021
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Ingår i: Journal of Lightwave Technology. - 0733-8724 .- 1558-2213. ; 39:18, s. 5699-5705
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Tidskriftsartikel (refereegranskat)abstract
- In this work we report the design and implementation of a very high speed retroreflective free space communication system between a ground station and a commercial unmanned aerial vehicle (UAV). The system uses a pixelated electro-absorption modulator (EAM) modulating retroreflector (MRR) to establish a data link operating at 500 Mbps at a range of 560 m and a bit error rate (BER) of 7.610-4. The MRR provides an effective aperture of 11mm and full field of view (FFOV) of 6.4. To the best of our knowledge, this is the fastest demonstration of an outdoor link of this type. In this paper the design and implementation of the system is described, as well as results from experimental trials.
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| 15. |
- Song, Miao, et al.
(författare)
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Tree-ring-based winter temperature reconstruction for East Asia over the past 700 years
- 2021
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Ingår i: Science China. Earth Sciences. - : Springer Science and Business Media LLC. - 1674-7313 .- 1869-1897. ; 64:6, s. 872-889
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Tidskriftsartikel (refereegranskat)abstract
- Almost all proxy-based temperature reconstructions for East Asia have hitherto been designed to resolve summer or annual temperature variability. Reconstruction for the winter temperature is still lacking. Here, we report an annually resolved, winter-season (December-February, DJF) temperature field reconstruction for East Asia covering the period 1300-2000 CE, based on 260 temperature-sensitive tree-ring records. The most striking feature of our new reconstruction is a significant long-term warming trend since the 14th century, which is associated with winter solar insolation at mid-latitudes of the Northern Hemisphere and the global anthropogenic impact. The amplitude of reconstructed winter temperature change over the study period was similar to 4.7 times greater than that for summer temperature, and the rate of winter temperature increase was similar to 6 times as much as that of summer temperature. The results from climate model simulations were consistent with the reconstruction, showing that the amplitude and rate of temperature change in winter were greater than that in summer. The reconstruction also suggests the possible influence of volcanic eruptions, anthropogenic activities and winter solar insolation on the winter temperature variations. Our result also suggests a long-term decrease in summer-to-winter temperature difference occurred in 1625 (+/- 24 years) CE.
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| 16. |
- Wu, Qi-Zhen, et al.
(författare)
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Long-term exposure to major constituents of fine particulate matter and neurodegenerative diseases : a population-based survey in the Pearl River Delta Region, China
- 2024
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Ingår i: Journal of Hazardous Materials. - : Elsevier. - 0304-3894 .- 1873-3336. ; 470
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Tidskriftsartikel (refereegranskat)abstract
- Background: Exposure to PM2.5 has been linked to neurodegenerative diseases, with limited understanding of constituent-specific contributions.Objectives: To explore the associations between long-term exposure to PM2.5 constituents and neurodegenerative diseases.Methods: We recruited 148,274 individuals aged ≥ 60 from four cities in the Pearl River Delta region, China (2020 to 2021). We calculated twenty-year average air pollutant concentrations (PM2.5 mass, black carbon (BC), organic matter (OM), ammonium (NH4+), nitrate (NO3-) and sulfate (SO42-)) at the individuals' home addresses. Neurodegenerative diseases were determined by self-reported doctor-diagnosed Alzheimer's disease (AD) and Parkinson's disease (PD). Generalized linear mixed models were employed to explore associations between pollutants and neurodegenerative disease prevalence.Results: PM2.5 and all five constituents were significantly associated with a higher prevalence of AD and PD. The observed associations generally exhibited a non-linear pattern. For example, compared with the lowest quartile, higher quartiles of BC were associated with greater odds for AD prevalence (i.e., the adjusted odds ratios were 1.81; 95% CI, 1.45–2.27; 1.78; 95% CI, 1.37–2.32; and 1.99; 95% CI, 1.54–2.57 for the second, third, and fourth quartiles, respectively).Conclusions: Long-term exposure to PM2.5 and its constituents, particularly combustion-related BC, OM, and SO42-, was significantly associated with higher prevalence of AD and PD in Chinese individuals.Environmental implication: PM2.5 is a routinely regulated mixture of multiple hazardous constituents that can lead to diverse adverse health outcomes. However, current evidence on the specific contributions of PM2.5 constituents to health effects is scarce. This study firstly investigated the association between PM2.5 constituents and neurodegenerative diseases in the moderately to highly polluted Pearl River Delta region in China, and identified hazardous constituents within PM2.5 that have significant impacts. This study provides important implications for the development of targeted PM2.5 prevention and control policies to reduce specific hazardous PM2.5 constituents.
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| 17. |
- Yang, Bao, et al.
(författare)
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Drought variability at the northern fringe of the Asian summer monsoon region over the past millennia
- 2014
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Ingår i: Climate Dynamics. - : Springer Science and Business Media LLC. - 0930-7575 .- 1432-0894. ; 43, s. 845-859
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Tidskriftsartikel (refereegranskat)abstract
- The northern fringe of the Asian summer monsoon region (NASM) in China refers to the most northwestern extent of the Asian summer monsoon. Understanding the characteristics and underlying mechanisms of drought variability at long and short time-scales in the NASM region is of great importance, because present and future water shortages are of great concern. Here, we used newly developed and existing tree-ring, historical documentary and instrumental data available for the region to identify spatial and temporal patterns, and possible mechanisms of drought variability, over the past two millennia. We found that drought variations were roughly consistent in the western (the Qilian Mountains and Hexi Corridor) and eastern (the Great Bend of the Yellow River, referred to as GBYR) parts of the NASM on decadal to centennial timescales. We also identified the spatial extent of typical multi-decadal GBYR drought events based on historical dryness/wetness data and the Monsoon Asia Drought Atlas. It was found that the two periods of drought, in AD 1625–1644 and 1975–1999, exhibited similar patterns: specifically, a wet west and a dry east in the NASM. Spatial characteristics of wetness and dryness were also broadly similar over these two periods, such that when drought occurred in the Karakoram Mountains, western Tianshan Mountains, the Pamirs, Mongolia, most of East Asia, the eastern Himalayas and Southeast Asia, a wet climate dominated in most parts of the Indian subcontinent. We suggest that the warm temperature anomalies in the tropical Pacific might have been mainly responsible for the recent 1975–1999 drought. Possible causes of the drought of 1625–1644 were the combined effects of the weakened Asian summer monsoon and an associated southward shift of the Pacific Intertropical Convergence Zone. These changes occurred due to a combination of Tibetan Plateau cooling together with more general Northern Hemisphere cooling, rather than being solely due to changes in the sea surface temperature of the tropical Pacific. Our results provide a benchmark for comparing and validating paleo-simulations from general circulation model of the variability of the Asian summer monsoon at decadal to centennial timescales.
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| 18. |
- Yang, Bao, et al.
(författare)
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Long-term decrease in Asian monsoon rainfall and abrupt climate change events over the past 6,700 years
- 2021
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - Washington : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 118:30
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Tidskriftsartikel (refereegranskat)abstract
- Asian summer monsoon (ASM) variability and its long-term ecological and societal impacts extending back to Neolithic times are poorly understood due to a lack of high-resolution climate proxy data. Here, we present a precisely dated and well-calibrated treering stable isotope chronology from the Tibetan Plateau with 1- to 5-y resolution that reflects high- to low-frequency ASM variability from 4680 BCE to 2011 CE. Superimposed on a persistent drying trend since the mid-Holocene, a rapid decrease in moisture availability between similar to 2000 and similar to 1500 BCE caused a dry hydroclimatic regime from similar to 1675 to similar to 1185 BCE, with mean precipitation estimated at 42 +/- 4% and 5 +/- 2% lower than during themid-Holocene and the instrumental period, respectively. This second-millennium-BCE megadrought marks the mid-to late Holocene transition, during which regional forests declined and enhanced aeolian activity affected northern Chinese ecosystems. We argue that this abrupt aridification starting similar to 2000 BCE contributed to the shift of Neolithic cultures in northern China and likely triggered human migration and societal transformation.
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| 19. |
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| 20. |
- Yen, Ying-Tzu, et al.
(författare)
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Prominent Enhancement of Cisplatin Efficacy with Optimized Methoxy Poly(ethylene glycol)-Polycaprolactone Block Copolymeric Nanoparticles
- 2020
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Ingår i: Journal of Biomedical Nanotechnology. - : AMER SCIENTIFIC PUBLISHERS. - 1550-7033 .- 1550-7041. ; 16:3, s. 335-343
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Tidskriftsartikel (refereegranskat)abstract
- Chemotherapy has been one of the major standard treatments for a variety of cancers. cis-Dichlorodiamminoplatiunum(II) (cisplatin, CDDP), as one of the anticancer agents, demonstrated excellent efficacy against tumor and has been an indispensable component in chemotherapy, chemoradiation, chemo-molecular targeted therapy and chemo-immunotherapy. However, its therapeutic concentration was limited since its inevitable toxicity. Previously, we have constructed CDDP-loaded nanoparticles (NPs) with mixture of poly(ethyleneglycol)-polycaprolactone (PEG-PCL) and polycarprolactone (HO-PCL) by a facile method. The most optimal proportion of the two copolymers was selected through a series of physical, chemical, cytological and histological evaluations. In the present study, we explored the mechanisms of NPs and observed the in vivo antitumor effect after administrating CDDP-loaded PEG-PCL NPs. Positron emission tomography as well as computed tomography (PET/CT) were adopted for detecting tumoral metabolic activity. Images from fluorescence microscope revealed superior cellular uptake of CDDP-loaded NPs with rhodamine B aggregated intracellularly in cancer cells. Similar apoptotic rates between free CDDP group and CDDP-loaded NPs group was measured by flow cytometry. Tumor volumes and murine weights confirmed the superiority of CDDP-loaded NPs in therapeutic efficacy as compared with free CDDP. Blood tests showed milder side effects in CDDP-loaded nanoparticle group. PET/CT images illustrated less uptake intensity of FDG in mice received CDDP-loaded NPs than free CDDP. Our results suggest that PEG-PCL/PCL NPs could be a promising antitumor drug carrier for CDDP delivery with solid efficacy and minor side effects.
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| 21. |
- Zhang, Huai, et al.
(författare)
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A global survey on the use of the international classification of diseases codes for metabolic dysfunction-associated fatty liver disease.
- 2024
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Ingår i: Hepatology international. - 1936-0541.
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Tidskriftsartikel (refereegranskat)abstract
- With the implementation of the 11th edition of the International Classification of Diseases (ICD-11) and the publication of the metabolic dysfunction-associated fatty liver disease (MAFLD) nomenclature in 2020, it is important to establish consensus for the coding of MAFLD in ICD-11. This will inform subsequent revisions of ICD-11.Using the Qualtrics XM and WJX platforms, questionnaires were sent online to MAFLD-ICD-11 coding collaborators, authors of papers, and relevant association members.A total of 890 international experts in various fields from 61 countries responded to the survey. We also achieved full coverage of provincial-level administrative regions in China. 77.1% of respondents agreed that MAFLD should be represented in ICD-11 by updating NAFLD, with no significant regional differences (77.3% in Asia and 76.6% in non-Asia, p=0.819). Over 80% of respondents agreed or somewhat agreed with the need to assign specific codes for progressive stages of MAFLD (i.e. steatohepatitis) (92.2%), MAFLD combined with comorbidities (84.1%), or MAFLD subtypes (i.e., lean, overweight/obese, and diabetic) (86.1%).This global survey by a collaborative panel of clinical, coding, health management and policy experts, indicates agreement that MAFLD should be coded in ICD-11. The data serves as a foundation for corresponding adjustments in the ICD-11 revision.
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| 22. |
- Zheng, Nianye, et al.
(författare)
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Magnesium facilitates the healing of atypical femoral fractures : A single-cell transcriptomic study
- 2022
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Ingår i: Materials Today. - : Elsevier. - 1369-7021 .- 1873-4103. ; 52, s. 43-62
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Tidskriftsartikel (refereegranskat)abstract
- Bisphosphonates (BPs)-associated atypical femoral fractures (AFFs) present with impaired fracture healing, yet the underlying mechanism is unclear, which prevents the development of effective therapy. Peripheral sensory nerve has been shown to regulate fracture healing via releasing neuropeptides. Here we show that long-term BPs pre-treatment leads to fracture non-union in rats, characterized by reduced expression of calcitonin gene-related peptide (CGRP, a predominant type of neuropeptides) and abundant fibrous tissues in the non-bridged fracture gap, mimicking clinical AFFs. By using single-cell RNA-sequencing, long-term BPs treatment was identified to promote transition of progenitor cells into a specific cluster of fibroblasts that actively deposit dense extracellular matrix (ECM) to prevent fracture callus bridging. Administration of exogenous CGRP at early stages of fracture repair, in contrast, eliminates the ECM-secreting fibroblast cluster, attenuates fibrogenesis, and facilitates callus bridging, suggesting CGRP is a promising agent to facilitate AFF healing. Accordingly, we have developed an innovative magnesium (Mg) containing hybrid intramedullary nail fixation system (Mg-IMN) to effectively rescue BPs-impaired fracture healing via elevating CGRP synthesis and release. Such device optimizes the fracture healing in BPs-pretreated rats, comparable to direct administration of CGRP. These findings address the indispensable role of CGRP in advancing the healing of AFFs and develop translational strategies to accelerate AFF healing by taking advantage of the CGRP-stimulating effect of Mg-based biodegradable orthopedic implant. The study also indicates fibrosis could be targeted by augmenting CGRP expression to accelerate fracture healing even under challenging scenarios where fibroblasts are aberrantly activated.
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| 23. |
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- 2019
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Tidskriftsartikel (refereegranskat)
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