| 1. |
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| 2. |
- Clark, Andrew G., et al.
(författare)
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Evolution of genes and genomes on the Drosophila phylogeny
- 2007
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 450:7167, s. 203-218
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Tidskriftsartikel (refereegranskat)abstract
- Comparative analysis of multiple genomes in a phylogenetic framework dramatically improves the precision and sensitivity of evolutionary inference, producing more robust results than single-genome analyses can provide. The genomes of 12 Drosophila species, ten of which are presented here for the first time (sechellia, simulans, yakuba, erecta, ananassae, persimilis, willistoni, mojavensis, virilis and grimshawi), illustrate how rates and patterns of sequence divergence across taxa can illuminate evolutionary processes on a genomic scale. These genome sequences augment the formidable genetic tools that have made Drosophila melanogaster a pre-eminent model for animal genetics, and will further catalyse fundamental research on mechanisms of development, cell biology, genetics, disease, neurobiology, behaviour, physiology and evolution. Despite remarkable similarities among these Drosophila species, we identified many putatively non-neutral changes in protein-coding genes, non-coding RNA genes, and cis-regulatory regions. These may prove to underlie differences in the ecology and behaviour of these diverse species.
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| 3. |
- Lindblad-Toh, Kerstin, et al.
(författare)
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Genome sequence, comparative analysis and haplotype structure of the domestic dog.
- 2005
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 1476-4687 .- 0028-0836. ; 438:7069, s. 803-19
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Tidskriftsartikel (refereegranskat)abstract
- Here we report a high-quality draft genome sequence of the domestic dog (Canis familiaris), together with a dense map of single nucleotide polymorphisms (SNPs) across breeds. The dog is of particular interest because it provides important evolutionary information and because existing breeds show great phenotypic diversity for morphological, physiological and behavioural traits. We use sequence comparison with the primate and rodent lineages to shed light on the structure and evolution of genomes and genes. Notably, the majority of the most highly conserved non-coding sequences in mammalian genomes are clustered near a small subset of genes with important roles in development. Analysis of SNPs reveals long-range haplotypes across the entire dog genome, and defines the nature of genetic diversity within and across breeds. The current SNP map now makes it possible for genome-wide association studies to identify genes responsible for diseases and traits, with important consequences for human and companion animal health.
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| 4. |
- Liu, Yuhuai, et al.
(författare)
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Effects of root exudate stoichiometry on CO2 emission from paddy soil
- 2020
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Ingår i: European Journal of Soil Biology. - : Elsevier BV. - 1164-5563 .- 1778-3615. ; 101
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Tidskriftsartikel (refereegranskat)abstract
- Root exudates are a labile source of carbon (C) for microorganisms that can lead to increased CO2 emission. Root exudates can vary in C:N stoichiometric ratio and their impact on microbially driven soil organic matter (SOM) turnover in paddy soils still remains unclear. The objective was to explore the underlying mechanisms involved in SOM decomposition due to root exudate (artificial) addition with three different C:N ratios (10, 20, and 40) during 45 days incubation. Different root exudates C:N ratios were obtained by adding mineral N and exudate components (glucose, oxalic acid, and glutamate) to paddy soil. N-only addition decreased dissolved organic C to limit CO2 emissions, which is an indicative of C sequestration. Conversely, simulated C:N stoichiometric ratios of root exudates significantly increased both microbial activity and metabolism without altering the microbial biomass C:N ratio. However, soil available dissolved organic C to NH4+ ratio decreased by exudates addition. The stoichiometric ratio of key C and N compound degrading enzymes activities increased only with C:N = 10 and remained unchanged with exudates C:N = 20 and 40. The qCO2 values increased with decreasing N-containing compounds in root exudates (i.e. highest CO2 emission was observed under C:N = 40 exudates addition). The results suggest that increasing exudates C:N ratio intensify CO2 emission due to high microbial N demand. Overall result show that root exudates C:N ratio and soil available N co-regulate on CO2 emission, which was controlled by microbial and potential extracellular enzyme activities.
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| 5. |
- Lozano, Rafael, et al.
(författare)
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Measuring progress from 1990 to 2017 and projecting attainment to 2030 of the health-related Sustainable Development Goals for 195 countries and territories: a systematic analysis for the Global Burden of Disease Study 2017
- 2018
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Ingår i: The Lancet. - : Elsevier. - 1474-547X .- 0140-6736. ; 392:10159, s. 2091-2138
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Tidskriftsartikel (refereegranskat)abstract
- Background: Efforts to establish the 2015 baseline and monitor early implementation of the UN Sustainable Development Goals (SDGs) highlight both great potential for and threats to improving health by 2030. To fully deliver on the SDG aim of “leaving no one behind”, it is increasingly important to examine the health-related SDGs beyond national-level estimates. As part of the Global Burden of Diseases, Injuries, and Risk Factors Study 2017 (GBD 2017), we measured progress on 41 of 52 health-related SDG indicators and estimated the health-related SDG index for 195 countries and territories for the period 1990–2017, projected indicators to 2030, and analysed global attainment. Methods: We measured progress on 41 health-related SDG indicators from 1990 to 2017, an increase of four indicators since GBD 2016 (new indicators were health worker density, sexual violence by non-intimate partners, population census status, and prevalence of physical and sexual violence [reported separately]). We also improved the measurement of several previously reported indicators. We constructed national-level estimates and, for a subset of health-related SDGs, examined indicator-level differences by sex and Socio-demographic Index (SDI) quintile. We also did subnational assessments of performance for selected countries. To construct the health-related SDG index, we transformed the value for each indicator on a scale of 0–100, with 0 as the 2·5th percentile and 100 as the 97·5th percentile of 1000 draws calculated from 1990 to 2030, and took the geometric mean of the scaled indicators by target. To generate projections through 2030, we used a forecasting framework that drew estimates from the broader GBD study and used weighted averages of indicator-specific and country-specific annualised rates of change from 1990 to 2017 to inform future estimates. We assessed attainment of indicators with defined targets in two ways: first, using mean values projected for 2030, and then using the probability of attainment in 2030 calculated from 1000 draws. We also did a global attainment analysis of the feasibility of attaining SDG targets on the basis of past trends. Using 2015 global averages of indicators with defined SDG targets, we calculated the global annualised rates of change required from 2015 to 2030 to meet these targets, and then identified in what percentiles the required global annualised rates of change fell in the distribution of country-level rates of change from 1990 to 2015. We took the mean of these global percentile values across indicators and applied the past rate of change at this mean global percentile to all health-related SDG indicators, irrespective of target definition, to estimate the equivalent 2030 global average value and percentage change from 2015 to 2030 for each indicator. Findings: The global median health-related SDG index in 2017 was 59·4 (IQR 35·4–67·3), ranging from a low of 11·6 (95% uncertainty interval 9·6–14·0) to a high of 84·9 (83·1–86·7). SDG index values in countries assessed at the subnational level varied substantially, particularly in China and India, although scores in Japan and the UK were more homogeneous. Indicators also varied by SDI quintile and sex, with males having worse outcomes than females for non-communicable disease (NCD) mortality, alcohol use, and smoking, among others. Most countries were projected to have a higher health-related SDG index in 2030 than in 2017, while country-level probabilities of attainment by 2030 varied widely by indicator. Under-5 mortality, neonatal mortality, maternal mortality ratio, and malaria indicators had the most countries with at least 95% probability of target attainment. Other indicators, including NCD mortality and suicide mortality, had no countries projected to meet corresponding SDG targets on the basis of projected mean values for 2030 but showed some probability of attainment by 2030. For some indicators, including child malnutrition, several infectious diseases, and most violence measures, the annualised rates of change required to meet SDG targets far exceeded the pace of progress achieved by any country in the recent past. We found that applying the mean global annualised rate of change to indicators without defined targets would equate to about 19% and 22% reductions in global smoking and alcohol consumption, respectively; a 47% decline in adolescent birth rates; and a more than 85% increase in health worker density per 1000 population by 2030. Interpretation: The GBD study offers a unique, robust platform for monitoring the health-related SDGs across demographic and geographic dimensions. Our findings underscore the importance of increased collection and analysis of disaggregated data and highlight where more deliberate design or targeting of interventions could accelerate progress in attaining the SDGs. Current projections show that many health-related SDG indicators, NCDs, NCD-related risks, and violence-related indicators will require a concerted shift away from what might have driven past gains—curative interventions in the case of NCDs—towards multisectoral, prevention-oriented policy action and investments to achieve SDG aims. Notably, several targets, if they are to be met by 2030, demand a pace of progress that no country has achieved in the recent past. The future is fundamentally uncertain, and no model can fully predict what breakthroughs or events might alter the course of the SDGs. What is clear is that our actions—or inaction—today will ultimately dictate how close the world, collectively, can get to leaving no one behind by 2030.
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| 6. |
- Xu, Changdan, et al.
(författare)
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CTCs Detection and Whole-exome Sequencing Might Be Used to Differentiate Benign and Malignant Pulmonary Nodules
- 2023
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Ingår i: Chinese Journal of Lung Cancer. - 1009-3419. ; 26:6, s. 449-460
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Tidskriftsartikel (refereegranskat)abstract
- Background and objective Low-density computed tomography (LDCT) improved early lung cancer diagnosis but introduces an excess of false-positive pulmonary nodules data. Hence, accurate diagnosis of early-stage lung cancer remains challenging. The purpose of the study was to assess the feasibility of using circulating tumour cells (CTCs) to differentiate malignant from benign pulmonary nodules. Materials and methods 122 patients with suspected malignant pulmonary nodules detected on chest CT in preparation for surgery were prospectively recruited. Peripheral blood samples were collected before surgery, and CTCs were identified upon isolation by size of epithelial tumour cells and morphological analysis. Laser capture microdissection, MALBAC amplification, and whole-exome sequencing were performed on 8 samples. The diagnostic efficacy of CTCs counting, and the genomic variation profile of benign and malignant CTCs samples were analysed. Results Using 2.5 cells/5 mL as the cut-off value, the area under the receiver operating characteristic curve was of 0.651 (95% confidence interval: 0.538-0.764), with a sensitivity and specificity of 0.526 and 0.800, respectively, and positive and negative predictive values of 91.1% and 30.3%, respectively. Distinct sequence variations differences in DNA damage repair-related and driver genes were observed in benign and malignant samples. TP53 mutations were identified in CTCs of four malignant cases; in particular, g.7578115T>C, g.7578645C>T, and g.7579472G>C were exclusively detected in all four malignant samples. Conclusion CTCs play an ancillary role in the diagnosis of pulmonary nodules. TP53 mutations in CTCs might be used to identify benign and malignant pulmonary nodules.
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| 7. |
- Xue, Ru, et al.
(författare)
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Variations of methane fluxes and methane microbial community composition with soil depth in the riparian buffer zone of a sponge city park
- 2023
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Ingår i: Journal of Environmental Management. - : Elsevier. - 0301-4797 .- 1095-8630. ; 339
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Tidskriftsartikel (refereegranskat)abstract
- Riparian buffers benefit both natural and man-made ecosystems by preventing soil erosion, retaining soil nu-trients, and filtering pollutants. Nevertheless, the relationship between vertical methane fluxes, soil carbon, and methane microbial communities in riparian buffers remains unclear. This study examined vertical methane fluxes, soil carbon, and methane microbial communities in three different soil depths (0-5 cm, 5-10 cm, and 10-15 cm) within a riparian buffer of a Sponge City Park for one year. Structural equation model (SEM) results demonstrated that vertical methane fluxes varied with soil depths (lambda =-0.37) and were primarily regulated by methanogenic community structure (lambda = 0.78). Notably, mathematical regression results proposed that mcrA/ pmoA ratio (R2 = 0.8) and methanogenic alpha diversity/methanotrophic alpha diversity ratio (R2 = 0.8) could serve as valid predictors of vertical variation in methane fluxes in the riparian buffer of urban river. These findings suggest that vertical variation of methane fluxes in riparian buffer soils is mainly influenced by carbon inputs and methane microbial abundance and community diversity. The study's results quantitatively the relationship between methane fluxes in riparian buffer soils and abiotic and biotic factors in the vertical di-rection, therefore contributing to the further development of mathematical models of soil methane emissions.
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| 8. |
- Zhang, Yinping, et al.
(författare)
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Ten cities cross-sectional questionnaire survey of children asthma and other allergies in China
- 2013
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Ingår i: Chinese Science Bulletin. - : Springer Science and Business Media LLC. - 1001-6538 .- 1861-9541. ; 58:34, s. 4182-4189
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Tidskriftsartikel (refereegranskat)abstract
- Asthma, rhinitis and eczema (allergic or non-allergic) have increased throughout the world during the last decades, especially among children. Changes in the indoor environment are suspected to be important causes. China has experienced a dramatic change in indoor environmental exposures during the past two decades. However, such changes and their associations with children's asthma and other health aspects have not been thoroughly studied. China, Children, Homes, Health (CCHH), Phase I, was a cross-sectional questionnaire survey of 48219 children 1-8 years old in 10 Chinese cities during 2010-2012. The questionnaire includes the International Study of Asthma and Allergies in Childhood (ISAAC) core health questions and additional questions regarding housing, life habits and outdoor environment. In health analyses, children aged 3-6 years old were included. The prevalences of doctor diagnosed asthma varied from 1.7% to 9.8% (mean 6.8%), a large increase from 0.91% in 1999 and 1.50% in 2000. The prevalence of wheeze, rhinitis and atopic eczema (last 12 months) varied from 13.9% to 23.7%, 24.0% to 50.8% and 4.8% to 15.8%, respectively. Taiyuan had the lowest prevalences of all illnesses and Shanghai the highest, except for wheezewhere the highest value was for Urumqi. We found (1) no obvious association between disease prevalences and ambient PM10 concentrations and (2) higher prevalences of disease in humid climates with hot summers and cold winters, but with no centrally heated buildings. Associations between the diseases and economic status as indexed by Gross Domestic Product (GDP) requires further study.
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| 9. |
- Bai, Xiaohong, et al.
(författare)
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Sensing applications of fiber Bragg gratings in single mode fibers with as-drawn 25 μm diameter cladding
- 2021
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Ingår i: Optics and Laser Technology. - : Elsevier Ltd. - 0030-3992 .- 1879-2545. ; 144
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Tidskriftsartikel (refereegranskat)abstract
- The sensing properties of fiber Bragg gratings (FBG) inscribed in single mode fiber with a 5 μm diameter core and 25 μm diameter cladding are studied experimentally for temperature, strain, bending, and surrounding refractive index. Compared to normal single mode fiber, the diameter of this fiber is 5 times smaller and it stretches 14.5 times more at the same applied load. Therefore, it is much more flexible and stretchable, while maintaining excellent optical quality at wavelengths near 1550 nm. In addition to a core mode back reflection resonance, strong FBGs inscribed in this fiber show a relatively small number of narrow bandwidth (0.7 nm) cladding mode resonances separated in wavelength by 2.5–6 nm. This relatively coarse spectral comb can then be used to sense many different kinds of perturbations involving core and cladding modes. In particular, unlike cladding-mode based sensors made from tilted FBGs, all resonances are of the same azimuthal order as the core mode (i.e. HE1m). This feature makes these gratings particularly sensitive to bending which causes the appearance of new resonances and reduced amplitudes of the original ones, each by up to 10 dB/mm−1 of curvature. On the other hand, the temperature sensitivities of all modes are similar to that of standard fiber (around 11 pm/oC) while strain sensitivities are somewhat higher (1.6–1.7 pm/μstrain). The surrounding refractive index sensitivity is also increased (by a factor of 3) over normal fiber, mostly due to the increased modal dispersion of the modes of the thinner cladding. Furthermore, it is possible to serially multiplex different gratings at different wavelengths by interleaving their resonance combs and preserving each grating identity in the combined spectrum.
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| 10. |
- Blösch, Günter, et al.
(författare)
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Twenty-three unsolved problems in hydrology (UPH) - a community perspective
- 2019
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Ingår i: Hydrological Sciences Journal. - : Informa UK Limited. - 0262-6667 .- 2150-3435. ; 64:10, s. 1141-1158
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Tidskriftsartikel (refereegranskat)abstract
- This paper is the outcome of a community initiative to identify major unsolved scientific problems in hydrology motivated by a need for stronger harmonisation of research efforts. The procedure involved a public consultation through online media, followed by two workshops through which a large number of potential science questions were collated, prioritised, and synthesised. In spite of the diversity of the participants (230 scientists in total), the process revealed much about community priorities and the state of our science: a preference for continuity in research questions rather than radical departures or redirections from past and current work. Questions remain focused on the process-based understanding of hydrological variability and causality at all space and time scales. Increased attention to environmental change drives a new emphasis on understanding how change propagates across interfaces within the hydrological system and across disciplinary boundaries. In particular, the expansion of the human footprint raises a new set of questions related to human interactions with nature and water cycle feedbacks in the context of complex water management problems. We hope that this reflection and synthesis of the 23 unsolved problems in hydrology will help guide research efforts for some years to come.
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| 11. |
- Cai, Xiaoping, et al.
(författare)
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Fabrication of Highly Porous CuAl Intermetallic by Thermal Explosion Using NaCl Space Holder
- 2018
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Ingår i: JOM. - : The Minerals, Metals, and Materials Society. - 1047-4838 .- 1543-1851. ; 70:10, s. 2173-2178
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Tidskriftsartikel (refereegranskat)abstract
- A high-porosity CuAl-based intermetallic compound with composition Cu-50 at.% Al has been successfully prepared by thermal explosion (TE) using NaCl as space holder. The results showed that the NaCl particles were completely removed from the green compact by water leaching. The temperature of the specimen during the TE and the evolution of the porous microstructure were investigated. The TE was ignited at 560°C, and the specimen temperature increased to 775°C in 3 s, resulting in formation of intermetallic CuAl and CuAl2 phases in the final product. A porous CuAl-based intermetallic compound with up to 62 vol.% open porosity was produced when adding 60 vol.% NaCl. The compound exhibited a bimodal pore size structure, including large pores (200 μm to 300 μm) that replicated the NaCl particles and small pores (5 μm to 10 μm) interspersed in the pore walls. Moreover, the large pores were interconnected by channels and formed an open CuAl-based intermetallic cellular structure, having great potential for use in heat exchange and filtration applications.
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| 12. |
- Cai, Xiaoping, et al.
(författare)
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Oxidation Resistance of Highly Porous Fe-Al Foams Prepared by Thermal Explosion
- 2018
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Ingår i: Metallurgical and Materials Transactions. A. - : Springer. - 1073-5623 .- 1543-1940. ; 49A:8, s. 3683-3691
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Tidskriftsartikel (refereegranskat)abstract
- Open-cell Fe-Al intermetallic foams were successfully prepared by a simple and energy-saving thermal explosion (TE) process. The effects of the Fe/Al molar ratio (Fe-(40–50) at. pct Al) and thermal treatment temperature on the TE temperature profile, phase composition, pore characteristics, and oxidation resistance of the prepared foams were investigated. The results showed that the Al content significantly influenced the ignition (Tig) and combustion (Tc) temperatures of the TE process; in particular, as the Al content decreased, Tig increased gradually from 623 °C to 636 °C and Tc decreased from 1059 °C to 981 °C. FeAl was identified as the dominant phase in the thermally treated foams. The Fe-Al intermetallic foams displayed an open porosity of 60 vol pct, with pores connected with each other to form an open pore structure. The formation of the pores was attributed to the expansion of interparticle pores in the pressed body during the TE reaction. X-ray photoelectron spectroscopy analysis of the Fe-50Al foam showed that the Al 2p and O 1s binding energies were 74.5 eV and at 531.4 eV, respectively. The formation of a surface alumina layer in the early stages of the oxidation process resulted in the parabolic oxidation rate law, and the Fe-50Al foams exhibited an excellent resistance to oxidation at 650 °C in air. These results suggest that the synthesized Fe-Al foams represent promising materials for applications involving an oxidizing environment and high temperatures.
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| 13. |
- Couch, Fergus J., et al.
(författare)
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Identification of four novel susceptibility loci for oestrogen receptor negative breast cancer
- 2016
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Ingår i: Nature Communications. - : NATURE PUBLISHING GROUP. - 2041-1723. ; 7:11375, s. 1-13
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Tidskriftsartikel (refereegranskat)abstract
- Common variants in 94 loci have been associated with breast cancer including 15 loci with genome-wide significant associations (P<5 x 10(-8)) with oestrogen receptor (ER)-negative breast cancer and BRCA1-associated breast cancer risk. In this study, to identify new ER-negative susceptibility loci, we performed a meta-analysis of 11 genome-wide association studies (GWAS) consisting of 4,939 ER-negative cases and 14,352 controls, combined with 7,333 ER-negative cases and 42,468 controls and 15,252 BRCA1 mutation carriers genotyped on the iCOGS array. We identify four previously unidentified loci including two loci at 13q22 near KLF5, a 2p23.2 locus near WDR43 and a 2q33 locus near PPIL3 that display genome-wide significant associations with ER-negative breast cancer. In addition, 19 known breast cancer risk loci have genome-wide significant associations and 40 had moderate associations (P<0.05) with ER-negative disease. Using functional and eQTL studies we implicate TRMT61B and WDR43 at 2p23.2 and PPIL3 at 2q33 in ER-negative breast cancer aetiology. All ER-negative loci combined account for similar to 11% of familial relative risk for ER-negative disease and may contribute to improved ER-negative and BRCA1 breast cancer risk prediction.
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| 14. |
- Fan, Ping, et al.
(författare)
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The influence of environmental factors on clinical pathological changes of patients with immunoglobulin A nephropathy from different areas of China
- 2018
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Ingår i: Renal failure. - 0886-022X. ; 40:1, s. 597-602
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Tidskriftsartikel (refereegranskat)abstract
- RESULTS: It was shown that the frequency of the patients with no mucosal infection in the urinary tract was higher in the Guangzhou group, while the frequencies of upper respiratory tract and biliary infections were lower when compared with those in the Xi'an group. Serum uric acid, alexin C3, creatinine and serum cholesterol concentrations were increased in the Guangzhou group, while triglyceride, glomerular filtration rate, and urine red blood cell count level decreased. IgA + IgM + C3 and IgA + IgG + IgM + C3 were found in most patients of the Xi'an group, whereas IgA + C3, IgA + IgM + C3 and IgA were more frequent in the Guangzhou group.CONCLUSION: It was found that differential environment, life habits and patterns in the two investigated areas obviously may influence the variable characteristics of IgAN patients.METHODS: Patients who were identified to have primary IgAN by renal biopsy diagnosis were recruited both from Shaanxi province hospital of traditional Chinese medicine and Guangdong province hospital of traditional Chinese medicine. Besides renal histopathology data, a number of clinical and laboratory data were collected.OBJECTIVES: The effects of regional characteristics of IgAN patients in different areas of China were investigated.
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| 15. |
- Fanourgakis, George S., et al.
(författare)
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Evaluation of global simulations of aerosol particle and cloud condensation nuclei number, with implications for cloud droplet formation
- 2019
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Ingår i: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 19:13, s. 8591-8617
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Tidskriftsartikel (refereegranskat)abstract
- A total of 16 global chemistry transport models and general circulation models have participated in this study; 14 models have been evaluated with regard to their ability to reproduce the near-surface observed number concentration of aerosol particles and cloud condensation nuclei (CCN), as well as derived cloud droplet number concentration (CDNC). Model results for the period 2011-2015 are compared with aerosol measurements (aerosol particle number, CCN and aerosol particle composition in the submicron fraction) from nine surface stations located in Europe and Japan. The evaluation focuses on the ability of models to simulate the average across time state in diverse environments and on the seasonal and short-term variability in the aerosol properties. There is no single model that systematically performs best across all environments represented by the observations. Models tend to underestimate the observed aerosol particle and CCN number concentrations, with average normalized mean bias (NMB) of all models and for all stations, where data are available, of -24% and -35% for particles with dry diameters >50 and >120nm, as well as -36% and -34% for CCN at supersaturations of 0.2% and 1.0%, respectively. However, they seem to behave differently for particles activating at very low supersaturations (<0.1%) than at higher ones. A total of 15 models have been used to produce ensemble annual median distributions of relevant parameters. The model diversity (defined as the ratio of standard deviation to mean) is up to about 3 for simulated N3 (number concentration of particles with dry diameters larger than 3nm) and up to about 1 for simulated CCN in the extra-polar regions. A global mean reduction of a factor of about 2 is found in the model diversity for CCN at a supersaturation of 0.2% (CCN0.2) compared to that for N3, maximizing over regions where new particle formation is important. An additional model has been used to investigate potential causes of model diversity in CCN and bias compared to the observations by performing a perturbed parameter ensemble (PPE) accounting for uncertainties in 26 aerosol-related model input parameters. This PPE suggests that biogenic secondary organic aerosol formation and the hygroscopic properties of the organic material are likely to be the major sources of CCN uncertainty in summer, with dry deposition and cloud processing being dominant in winter. Models capture the relative amplitude of the seasonal variability of the aerosol particle number concentration for all studied particle sizes with available observations (dry diameters larger than 50, 80 and 120nm). The short-term persistence time (on the order of a few days) of CCN concentrations, which is a measure of aerosol dynamic behavior in the models, is underestimated on average by the models by 40% during winter and 20% in summer. In contrast to the large spread in simulated aerosol particle and CCN number concentrations, the CDNC derived from simulated CCN spectra is less diverse and in better agreement with CDNC estimates consistently derived from the observations (average NMB -13% and -22% for updraft velocities 0.3 and 0.6ms-1, respectively). In addition, simulated CDNC is in slightly better agreement with observationally derived values at lower than at higher updraft velocities (index of agreement 0.64 vs. 0.65). The reduced spread of CDNC compared to that of CCN is attributed to the sublinear response of CDNC to aerosol particle number variations and the negative correlation between the sensitivities of CDNC to aerosol particle number concentration (Nd=Na) and to updraft velocity (Nd=w). Overall, we find that while CCN is controlled by both aerosol particle number and composition, CDNC is sensitive to CCN at low and moderate CCN concentrations and to the updraft velocity when CCN levels are high. Discrepancies are found in sensitivities Nd=Na and Nd=w; models may be predisposed to be too "aerosol sensitive" or "aerosol insensitive" in aerosol-cloud-climate interaction studies, even if they may capture average droplet numbers well. This is a subtle but profound finding that only the sensitivities can clearly reveal and may explain intermodel biases on the aerosol indirect effect.
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| 16. |
- Feng, Peizhong, et al.
(författare)
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Combustion synthesis of (Mo1-xCrx)Si-2 (x=0.00-0.30) alloys in SHS mode
- 2012
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Ingår i: Advanced Powder Technology. - : Elsevier BV. - 0921-8831 .- 1568-5527. ; 23:2, s. 133-138
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Tidskriftsartikel (refereegranskat)abstract
- Combustion synthesis was adopted to successfully synthesize molybdenum-silicon-chromium (Mo-Si-Cr) alloys by the mode of self-propagating high-temperature synthesis (SHS). The experimental study of combustion synthesis of Mo-Si-Cr alloys was conducted on elemental powder compacts. Powder compacts with nominal compositions including MoSi2, (Mo0.95Cr0.05)Si-2, (Mo0.90Cr0.10)Si-2, (Mo0.85Cr0.15)Si-2, (Mo0.80Cr0.20)Si-2, (Mo0.75Cr0.25)Si-2 and (Mo0.20Cr0.30)Si-2 were employed in combustion synthesis experiments. The combustion mode, combustion temperature, flame-front propagation velocity and product structure were investigated. The results showed that Mo-Si-Cr alloys were synthesized by an unsteady state combustion mode with a spiral-trajectory reaction front. The peak combustion temperature reduced with the addition of Cr to Mo-Si system. The flame-front propagation velocity decreased with an increase in Cr content of the powder compact. The X-ray diffraction (XRD) results showed that the crystal structure of the combustion product changed from CIIb-type structure (Mo0.90Cr0.10)Si-2 to C40-type structure (Mo0.80Cr0.15)Si-2 with increase in Cr content of Mo-Cr-Si alloys. The intensities of diffraction peaks of the C40-type phase gradually increased with increase in Cr content.
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| 17. |
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| 18. |
- Gao, Chaobing, et al.
(författare)
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Up-regulated expression of Dicer reveals poor prognosis in laryngeal squamous cell carcinoma
- 2014
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Ingår i: Acta Oto-Laryngologica. - : Informa UK Limited. - 0001-6489 .- 1651-2251. ; 134:9, s. 959-963
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Tidskriftsartikel (refereegranskat)abstract
- Conclusions: Increased expression of Dicer may be a prognostic biomarker for patients with laryngeal squamous cell carcinoma (LSCC). Objectives: Recent studies have shown that many microRNAs (miRNAs) play an important role in the development and progression of human cancers. Dicer, one of the most important enzymes of the miRNA machinery, performs the final step of biogenesis of miRNAs. This study aimed to investigate the impact of Dicer expression on patient survival in human LSCC. Methods: We detected the expression of Dicer in larynx tissue specimens from 76 LSCC samples and 26 polyps by immunohistochemistry. The clinicopathological and prognostic significance of Dicer expression was investigated in LSCC. Results: Our data showed that the expression of Dicer was significantly higher in the LSCC than in the polyp tissue specimens. Moreover, the expression level of Dicer was significantly associated with the pTNM stage and tumor lymph node metastasis. Kaplan-Meier survival analyses revealed a strong association between tumor Dicer expression and the survival of the patients with LSCC.
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| 19. |
- Jiang, Zhiwu, et al.
(författare)
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Combustion synthesis and mechanical properties of MoSi2-ZrB2-SiC ceramics
- 2018
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Ingår i: Journal of the Ceramic Society of Japan. - : Ceramic Society of Japan. - 1882-0743 .- 1348-6535. ; 126:7, s. 504-509
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Tidskriftsartikel (refereegranskat)abstract
- MoSi2ZrB2SiC ceramics were synthesized using Mo, Zr, Si and B4C powders by self-propagating high-temperature synthesis and densifying by spark plasma sintering. The effects of MoSi2 content on the combustion synthesis process, microstructure, and mechanical properties of the ceramics were investigated. The results showed that combustion synthesis is an unstable mode, spiral combustion. The Gibbs calculations and combustion temperature curves indicate there are two reactions occurring at the same time. The volume fraction of the four different phases and their relative densities were also measured and calculated. Compared to pure MoSi2, the 1.0MoSi20.2ZrB20.1SiC (M10) ceramic exhibits excellent mechanical properties with its maximum Vickers hardness and fracture toughness being 14.0 GPa and of 5.5 MPa m1/2, respectively. The hardness is in agreement with the rule of mixture. The morphology of indentation cracks reveals that the fracture toughness improves as a result of toughening mechanisms such as crack bridge, crack deflection, and microcracks.
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| 20. |
- Jiao, Xinyang, et al.
(författare)
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Microstructure Evolution and Pore Formation Mechanism of Porous TiAl3 Intermetallics via Reactive Sintering
- 2018
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Ingår i: Acta Metallurgica Sinica (English Letters). - : Springer. - 1006-7191 .- 2194-1289. ; 31:4, s. 440-448
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Tidskriftsartikel (refereegranskat)abstract
- Porous TiAl3 intermetallics were fabricated through vacuum reactive sintering from Ti–75Al at.% elemental powder mixture. The phase compositions, expansion behaviors, pore characteristics and microstructure evolution of TiAl3 intermetallics were investigated, and the pore formation mechanism was also proposed. It was found that the actual temperature of compacts showed an acute climb from 668 to 1244 °C in 166s, while the furnace temperature maintained the linear growth of 5 °C/min, which indicated that an obvious thermal explosion (TE) reaction occurred during sintering, and only single-phase TiAl3 intermetallic was synthesized in TE products. The open porosity increased from 22.2 (green compact) to 32.8% after reactive diffusion sintering at 600 °C and rised to 58.7% after TE, then decreased to 51.2% after high-temperature homogenization at 1100 °C. Therefore, TE reaction is the dominated pore formation mechanism of porous TiAl3 intermetallics. The pore evolution in porous TiAl3 intermetallics occurred by the following mechanisms: certain intergranular pores remained among powder particles of green compact, then low-temperature sintering resulted in a further increase in porosity due to the Kirkendall effect. Moreover, TE reaction gave rise to a dramatic volume expansion because of the rapid increase in temperature, and high-temperature sintering caused densification and a slight shrinkage.
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| 21. |
- Kirkevag, Alf, et al.
(författare)
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A production-tagged aerosol module for Earth system models, OsloAero5.3-extensions and updates for CAM5.3-Oslo
- 2018
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Ingår i: Geoscientific Model Development. - : Copernicus GmbH. - 1991-959X .- 1991-9603. ; 11:10, s. 3945-3982
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Tidskriftsartikel (refereegranskat)abstract
- We document model updates and present and discuss modeling and validation results from a further developed production-tagged aerosol module, OsloAero5.3, for use in Earth system models. The aerosol module has in this study been implemented and applied in CAM5.3-Oslo. This model is based on CAM5.3-CESM1.2 and its own predecessor model version CAM4-Oslo. OsloAero5.3 has improved treatment of emissions, aerosol chemistry, particle life cycle, and aerosol-cloud interactions compared to its predecessor OsloAero4.0 in CAM4-Oslo. The main new features consist of improved aerosol sources; the module now explicitly accounts for aerosol particle nucleation and secondary organic aerosol production, with new emissions schemes also for sea salt, dimethyl sulfide (DMS), and marine primary organics. Mineral dust emissions are updated as well, adopting the formulation of CESM1.2. The improved model representation of aerosol-cloud interactions now resolves heterogeneous ice nucleation based on black carbon (BC) and mineral dust calculated by the model and treats the activation of cloud condensation nuclei (CCN) as in CAM5.3. Compared to OsloAero4.0 in CAM4-Oslo, the black carbon (BC) mass concentrations are less excessive aloft, with a better fit to observations. Near-surface mass concentrations of BC and sea salt aerosols are also less biased, while sulfate and mineral dust are slightly more biased. Although appearing quite similar for CAM5.3-Oslo and CAM4-Oslo, the validation results for organic matter (OM) are inconclusive, since both of the respective versions of OsloAero are equipped with a limited number of OM tracers for the sake of computational efficiency. Any information about the assumed mass ratios of OM to organic carbon (OC) for different types of OM sources is lost in the transport module. Assuming that observed OC concentrations scaled by 1.4 are representative for the modeled OM concentrations, CAM5.3-Oslo with OsloAero5.3 is slightly inferior for the very sparsely available observation data. Comparing clear-sky column-integrated optical properties with data from ground-based remote sensing, we find a negative bias in optical depth globally; however, it is not as strong as in CAM4-Oslo, but has positive biases in some areas typically dominated by mineral dust emissions. Aerosol absorption has a larger negative bias than the optical depth globally. This is reflected in a lower positive bias in areas where mineral dust is the main contributor to absorption. Globally, the low bias in absorption is smaller than in CAM4-Oslo. The Angstrom parameter exhibits small biases both globally and regionally, suggesting that the aerosol particle sizes are reasonably well represented. Cloud-top droplet number concentrations over oceans are generally underestimated compared to satellite retrievals, but seem to be overestimated downwind of major emissions of dust and biomass burning sources. Finally, we find small changes in direct radiative forcing at the top of the atmosphere, while the cloud radiative forcing due to anthropogenic aerosols is now more negative than in CAM4-Oslo, being on the strong side compared to the multi-model estimate in IPCC AR5. Although not all validation results in this study show improvement for the present CAM5.3-Oslo version, the extended and updated aerosol module OsloAero5.3 is more advanced and applicable than its predecessor OsloAero4.0, as it includes new parameterizations that more readily facilitate sensitivity and process studies and use in climate and Earth system model studies in general.
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| 22. |
- Liu, Zhiyong, et al.
(författare)
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Compensating Effects Between Climate and Underlying Characteristics on Watershed Water Loss
- 2023
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Ingår i: Journal of Geophysical Research - Atmospheres. - 2169-897X .- 2169-8996. ; 128:6
-
Tidskriftsartikel (refereegranskat)abstract
- Identifying climate impacts on watershed water loss (evapotranspiration) generally involves the interactions with land surface change (e.g., vegetation dynamics and anthropogenic disturbances). Here, we seek to understand the compensating effects of climate and underlying characteristics on watershed evapotranspiration. In this regard, an analytical solution was derived by using a simple water-energy partitioning framework for separating the individual contributions of climate and underlying characteristics to changes in watershed actual evapotranspiration between 1930-1970 and 1971-2008 over global 87 basins. We found that for the basins with larger increases in the total evapotranspiration, a positive underlying characteristic-related contribution is dominant, rather than the climate-related contribution. Tradeoffs (i.e., the compensating effects) between the contributions of climate and underlying characteristics to evaporative water loss were also identified in a few basins where there were relatively large changes in the underlying characteristic-related evapotranspiration but only a slight change in the total evapotranspiration. This suggests that the climate contribution in evapotranspiration may offset the effect of underlying characteristic-related changes over these basins, associated with stronger hydrological resilience under the double impacts of both climate and underlying factors. The results also indicate that the underlying characteristics exert greater contributions to the changes in the total evapotranspiration rather than the climate variation, and the underlying characteristic-related evapotranspiration variations are closely related to the changes in reservoirs and land-use types of the basins. The presented findings may provide an insightful understanding of interactions among climate, water, and underlying characteristics over global basins.
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| 23. |
- Murray, Christopher J. L., et al.
(författare)
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Population and fertility by age and sex for 195 countries and territories, 1950–2017: a systematic analysis for the Global Burden of Disease Study 2017
- 2018
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Ingår i: The Lancet. - 1474-547X .- 0140-6736. ; 392:10159, s. 1995-2051
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Tidskriftsartikel (refereegranskat)abstract
- Background: Population estimates underpin demographic and epidemiological research and are used to track progress on numerous international indicators of health and development. To date, internationally available estimates of population and fertility, although useful, have not been produced with transparent and replicable methods and do not use standardised estimates of mortality. We present single-calendar year and single-year of age estimates of fertility and population by sex with standardised and replicable methods. Methods: We estimated population in 195 locations by single year of age and single calendar year from 1950 to 2017 with standardised and replicable methods. We based the estimates on the demographic balancing equation, with inputs of fertility, mortality, population, and migration data. Fertility data came from 7817 location-years of vital registration data, 429 surveys reporting complete birth histories, and 977 surveys and censuses reporting summary birth histories. We estimated age-specific fertility rates (ASFRs; the annual number of livebirths to women of a specified age group per 1000 women in that age group) by use of spatiotemporal Gaussian process regression and used the ASFRs to estimate total fertility rates (TFRs; the average number of children a woman would bear if she survived through the end of the reproductive age span [age 10–54 years] and experienced at each age a particular set of ASFRs observed in the year of interest). Because of sparse data, fertility at ages 10–14 years and 50–54 years was estimated from data on fertility in women aged 15–19 years and 45–49 years, through use of linear regression. Age-specific mortality data came from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 estimates. Data on population came from 1257 censuses and 761 population registry location-years and were adjusted for underenumeration and age misreporting with standard demographic methods. Migration was estimated with the GBD Bayesian demographic balancing model, after incorporating information about refugee migration into the model prior. Final population estimates used the cohort-component method of population projection, with inputs of fertility, mortality, and migration data. Population uncertainty was estimated by use of out-of-sample predictive validity testing. With these data, we estimated the trends in population by age and sex and in fertility by age between 1950 and 2017 in 195 countries and territories. Findings: From 1950 to 2017, TFRs decreased by 49·4% (95% uncertainty interval [UI] 46·4–52·0). The TFR decreased from 4·7 livebirths (4·5–4·9) to 2·4 livebirths (2·2–2·5), and the ASFR of mothers aged 10–19 years decreased from 37 livebirths (34–40) to 22 livebirths (19–24) per 1000 women. Despite reductions in the TFR, the global population has been increasing by an average of 83·8 million people per year since 1985. The global population increased by 197·2% (193·3–200·8) since 1950, from 2·6 billion (2·5–2·6) to 7·6 billion (7·4–7·9) people in 2017; much of this increase was in the proportion of the global population in south Asia and sub-Saharan Africa. The global annual rate of population growth increased between 1950 and 1964, when it peaked at 2·0%; this rate then remained nearly constant until 1970 and then decreased to 1·1% in 2017. Population growth rates in the southeast Asia, east Asia, and Oceania GBD super-region decreased from 2·5% in 1963 to 0·7% in 2017, whereas in sub-Saharan Africa, population growth rates were almost at the highest reported levels ever in 2017, when they were at 2·7%. The global average age increased from 26·6 years in 1950 to 32·1 years in 2017, and the proportion of the population that is of working age (age 15–64 years) increased from 59·9% to 65·3%. At the national level, the TFR decreased in all countries and territories between 1950 and 2017; in 2017, TFRs ranged from a low of 1·0 livebirths (95% UI 0·9–1·2) in Cyprus to a high of 7·1 livebirths (6·8–7·4) in Niger. The TFR under age 25 years (TFU25; number of livebirths expected by age 25 years for a hypothetical woman who survived the age group and was exposed to current ASFRs) in 2017 ranged from 0·08 livebirths (0·07–0·09) in South Korea to 2·4 livebirths (2·2–2·6) in Niger, and the TFR over age 30 years (TFO30; number of livebirths expected for a hypothetical woman ageing from 30 to 54 years who survived the age group and was exposed to current ASFRs) ranged from a low of 0·3 livebirths (0·3–0·4) in Puerto Rico to a high of 3·1 livebirths (3·0–3·2) in Niger. TFO30 was higher than TFU25 in 145 countries and territories in 2017. 33 countries had a negative population growth rate from 2010 to 2017, most of which were located in central, eastern, and western Europe, whereas population growth rates of more than 2·0% were seen in 33 of 46 countries in sub-Saharan Africa. In 2017, less than 65% of the national population was of working age in 12 of 34 high-income countries, and less than 50% of the national population was of working age in Mali, Chad, and Niger. Interpretation: Population trends create demographic dividends and headwinds (ie, economic benefits and detriments) that affect national economies and determine national planning needs. Although TFRs are decreasing, the global population continues to grow as mortality declines, with diverse patterns at the national level and across age groups. To our knowledge, this is the first study to provide transparent and replicable estimates of population and fertility, which can be used to inform decision making and to monitor progress. Funding: Bill & Melinda Gates Foundation.
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| 24. |
- Tang, Hu, et al.
(författare)
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Boron-Rich Molybdenum Boride with Unusual Short-Range Vacancy Ordering, Anisotropic Hardness, and Superconductivity
- 2020
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Ingår i: Chemistry of Materials. - : AMER CHEMICAL SOC. - 0897-4756 .- 1520-5002. ; 32:1, s. 459-467
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Tidskriftsartikel (refereegranskat)abstract
- Determination of the structures of materials involving more light elements such as boron-rich compounds is challenging and technically important in understanding their varied compositions and superior functionalities. Here we resolve the long-standing uncertainties in structure and composition about the highest boride (termed MoB4, Mo1-xB3, or MoB3) through the rapid formation of large sized boron-rich molybdenum boride under pressure. Using high-quality single-crystal X-ray diffraction analysis and aberration-corrected scanning transmission electron microscopy, we reveal that boron-rich molybdenum boride with a composition of Mo0.757B3 exhibits P6(3)/mmc symmetry with a partial occupancy of 0.514 in 211 Mo sites (Mol), and direct observations reveal the short-range ordering of cation vacancies in (010) crystal planes. Large anisotropic Young's moduli and Vickers hardness are seen for Mo0.757B3, which may be attributed by its two-dimensional boron distributions. Mo0.757B3 is also found to be superconducting with a transition temperature (T-c) of 2.4 K, which was confirmed by measurements of resistivity and magnetic susceptibility. Theoretical calculations suggest that the partial occupancy of Mo atoms plays a crucial role in the emergence of superconductivity.
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| 25. |
- Wang, Xiaohong, et al.
(författare)
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Effects of tungsten and aluminum additions on the formation of molybdenum disilicide by mechanically-induced self-propagating reaction
- 2010
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Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 490:1, s. 388-392
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Tidskriftsartikel (refereegranskat)abstract
- The effects of tungsten and aluminum additions to Mo–Si system on the formation of MoSi2 by mechanically-induced self-propagating reaction in a high-energy ball mill were investigated by X-ray diffraction. The incubation time for mechanically-induced self-propagating reaction to form MoSi2 was 90 min in Mo–Si system. With the addition of tungsten to Mo–Si system, the incubation time of mechanically-induced self-propagating reaction of (Wx,Mo1−x)Si2 system was prolonged. It was due to the decrease of adiabatic temperature with increase in x, and the mechanically-induced self-propagating reaction was not observed until 150 min of high-energy milling in (Wx,Mo1−x)Si2 powder sample with x equals to 0.4. Conversely, the minor aluminum (y < 0.2 in Mo(Si1−y,Aly)2 system) substituting for silicon had shorten the incubation period and accelerated the reaction. When tungsten and aluminium were added simultaneously to Mo–Si system, the mechanically-induced self-propagating reaction was observed in (W0.1,Mo0.9)(Si0.9,Al0.1)2 sample, but it was not observed in (W0.2,Mo0.8)(Si0.8,Al0.2)2 and (W0.3,Mo0.7)(Si0.7,Al0.3)2 samples.
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| 26. |
- Wang, Zhang, et al.
(författare)
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Highly porous open cellular TiAl-based intermetallics fabricated by thermal explosion with space holder process
- 2016
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Ingår i: Intermetallics (Barking). - : Elsevier BV. - 0966-9795 .- 1879-0216. ; 68, s. 95-100
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Tidskriftsartikel (refereegranskat)abstract
- High porosity TiAl-based intermetallics were prepared through thermal explosion (TE) from Ti–50Al at.% powders with NaCl as soluble template. The results showed that the space holder particles of NaCl were removed completely in green compacts, and porous Ti–Al materials were synthesized via a low-energy consumption method of TE at a temperature of 600 °C. TiAl was evolved as dominant phase in sintered materials at 1100 °C. With adding 80 vol.% NaCl to Ti–50Al at.% powders, the open porosity was significantly elevated up to 84%. Moreover, the porous materials exhibited a bimodal pore size distribution: large pores (200–500 μm) replicating NaCl particles and small pores (<50 μm) embedded in pore walls. The interconnected small and large pores make open cellular porous TiAl materials, which prescribe them promising for a wide range of applications in separation, heat insulation and catalysis.
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| 27. |
- Xu, Guobao, et al.
(författare)
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Century-scale temperature variability and onset of industrial-era warming in the Eastern Tibetan Plateau
- 2019
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Ingår i: Climate Dynamics. - : Springer Science and Business Media LLC. - 0930-7575 .- 1432-0894. ; 53:7-8, s. 4569-4590
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Tidskriftsartikel (refereegranskat)abstract
- To improve our understanding of climate variability in the Tibetan Plateau (TP) and its sensitivity to external forcings, recent temperature changes need to be placed in a long-term historical context. Here, we present two tree-ring based temperature reconstructions: a 1003-year (1000-2002 CE) annual temperature reconstruction for the northeastern TP (NETP) based on seven series and a 522-year (1489-2010 CE) summer (June-July-August) temperature reconstruction for the southeastern TP (SETP) based on 11 series. Our reconstructions show six centuries of generally warm NETP temperatures (1000-1586 CE), followed by a transition to cooler temperatures (1587-1887 CE for NETP and 1588-1930 CE for SETP). The transition from the Medieval Climate Anomaly to the Little Ice Age thus happened in the 1580s in NETP and SETP, which is about 150 years later than in larger-scale (e.g. Asia and the Northern Hemisphere) temperature reconstructions. We found that TP temperature variability, especially in SETP, was influenced by the Atlantic multi-decadal oscillation and that the twentieth century was the warmest on record in NETP and SETP. Our reconstructions and climate model simulations both show industrial-era warming trends, the onset of which happened earlier in NETP (1812 CE) compared to SETP (1887 CE) and other temperature reconstructions for Western China, East Asia, Asia, and the Northern Hemisphere. The early NETP onset of industrial-era warming can likely be explained by NETP's faster warming rate and by local feedback factors (i.e., ice-snow cover-albedo). Comparisons between climate model simulations and our reconstructions reveal that cooler TP temperatures from 1600 to 1800 CE might be related to land-use and land-cover change.
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| 28. |
- Xu, Guobao, et al.
(författare)
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Tree ring O-18's indication of a shift to a wetter climate since the 1880s in the western Tianshan Mountains of northwestern China
- 2015
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Ingår i: Journal of Geophysical Research - Atmospheres. - 2169-897X .- 2169-8996. ; 120:13, s. 6409-6425
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Tidskriftsartikel (refereegranskat)abstract
- Central Asian droughts have drastically and significantly affected agriculture and water resource management in these arid and semiarid areas. Based on tree ring O-18 from native, dominant Schrenk spruce (Picea schrenkiana Fisch. et Mey.), we developed a 300year (1710-2010) standard precipitation-evaporation index (SPEI) reconstruction from January to August for China's western Tianshan Mountains. The regression model explained 37.6% of the variation in the SPEI reconstruction during the calibration period from 1950 to 2010. Comparison with previous drought reconstructions confirmed the robustness of our reconstruction. The 20th century has been a relatively wet period during the past 300years. The SPEI showed quasi 2, 5, and 10year cycles. Several pluvials and droughts with covariability over large areas were revealed clearly in the reconstruction. The two longest pluvials (lasting for 12years), separated by 50years, appeared in the 1900s and the 1960s. The most severe drought occurred from 1739 to 1761 and from 1886 to 1911 was the wettest period since 1710. Compared to previous investigations of hydroclimatic changes in the western Tianshan Mountains, our reconstruction revealed more low-frequency variability and indicated that climate in the western Tianshan Mountains shifted from dry to wet in 1886. This regime shift was generally consistent with other moisture reconstructions for the northeastern Tibetan Plateau and northern Pakistan and may have resulted from a strengthened westerly circulation. The opposite hydrological trends in the western Tianshan Mountains and southeastern Tibetan Plateau reveal a substantial influence of strengthened westerlies and weakening of the Indian summer monsoon.
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| 29. |
- Yang, Liu, et al.
(författare)
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Prenatal and postnatal early life exposure to greenness and particulate matter of different size fractions in relation to childhood rhinitis : A multi-center study in China
- 2024
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Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 938
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Tidskriftsartikel (refereegranskat)abstract
- The impact of early life exposure to residential greenness on childhood rhinitis and its interaction with particulate matter (PM) of different size fractions remain inconsistent. Herein, we recruited 40,486 preschool children from randomly selected daycare centers in 7 cities in China from 2019 to 2020, and estimated exposure to residential greenness by the normalized difference vegetation index (NDVI) with a 500 m buffer. Exposure to ambient PM (PM1, PM2.5, and PM10) was evaluated using a satellite-based prediction model (daily, at a resolution of 1 km × 1 km). By mixed-effect logistic regression, NDVI values during pregnancy, in the first (0–1 year old) and the second (1–2 years old) year of life were negatively associated with lifetime rhinitis (LR) and current rhinitis (CR) (P < 0.001). PM in the same time windows was associated with increased risks of LR and CR in children, with smaller size fraction of PM showing greater associations. The negative associations between prenatal and postnatal NDVI and LR and CR in preschool children remained robust after adjusting for concomitant exposure to PM, whereas the associations of postnatal NDVI and rhinitis showed significant interactions with PM. At lower levels of PM, postnatal NDVI remained negatively associated with rhinitis and was partly mediated by PM (10.0–40.9 %), while at higher levels of PM, the negative associations disappeared or even turned positive. The cut-off levels of PM were identified for each size fraction of PM. In conclusion, prenatal exposure to greenness had robust impacts in lowering the risk of childhood rhinitis, while postnatal exposure to greenness depended on the co-exposure levels to PM. This study revealed the complex interplay of greenness and PM on rhinitis in children. The exposure time window in prenatal or postnatal period and postnatal concomitant PM levels played important roles in influencing the associations between greenness, PM and rhinitis.
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| 30. |
- Zhang, Chao, et al.
(författare)
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An Experimental Novel Study : Angelica sinensis Prevents Epidural Fibrosis in Laminectomy Rats via Downregulation of Hydroxyproline, IL-6, and TGF-beta 1
- 2013
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Ingår i: Evidence-based Complementary and Alternative Medicine. - : Hindawi Limited. - 1741-427X .- 1741-4288. ; , s. 291814-
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Tidskriftsartikel (refereegranskat)abstract
- With laminectomy being widely accepted as the treatment for lumbar disorders, epidural fibrosis (EF) is a common complication for both the patients and the surgeons alike. Currently, EF is thought to cause recurrent postoperative pain after laminectomy or after discectomy. Angelica sinensis is a traditional Chinese medicine which has shown anti-inflammatory, antifibrotic, and antiproliferative properties. The object of this study was to investigate the effects of Angelica sinensis on the prevention of postlaminectomy EF formation in a rat model. A controlled double-blinded study was conducted in sixty healthy adult Wistar rats that underwent laminectomy at the L1-L2 levels. They were divided randomly into 3 groups according to the treatment method, with 20 in each group: (1) Angelica sinensis treatment group, (2) saline treatment group, and (3) sham group (laminectomy without treatment). All rats were euthanized humanely 4 weeks after laminectomy. The hydroxyproline content, Rydell score, vimentin cells density, fibroblasts density, inflammatory cells density, and inflammatory factors expressions all suggested better results in Angelica sinensis group than the other two groups. Topical application of Angelica sinensis could inhibit fibroblasts proliferation and TGF-beta 1 and IL-6 expressions and prevent epidural scar adhesion in postlaminectomy rat model.
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| 31. |
- Zhang, Zhenzong, et al.
(författare)
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Unveiling the role of Ag-Sb bimetallic S-scheme heterojunction for vis-NIR-light driven selective photoreduction CO2 to CH4
- 2022
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Ingår i: Applied Catalysis B: Environmental. - : Elsevier BV. - 0926-3373. ; 319
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Tidskriftsartikel (refereegranskat)abstract
- The construction of interfacial engineered heterojunctions is an effective strategy to broaden the optical response and facilitate charge separation. Herein, a novel 0D/1D Ag2S/Sb2S3 heterojunction is prepared by in-situ growth of Ag2S quantum dots on Sb2S3 nanorods using a simple hydrothermal approach. The 10% Ag2S/Sb2S3 (10AS) heterojunction exhibited efficient CO2 photoreduction activity with a CH4 yield of 6.75 µmol g−1 h−1, which is six times higher than that of pure Sb2S3 NTs. The CH4 selectivity of the 10AS heterojunction reach 96.1%, owing to the construction of dual-metal sites. Intriguingly, the composite photocatalyst could be extended to infrared light, leading to the full utilization of the incident light. In the 10AS heterojunction, the formation of Ag-S-Sb type covalent bonds is demonstrated by Raman and XAFS tests. The pathways of CO2 conversion to CH4 are discussed in detail. Therefore, the work provides a promising strategy for highly selective and efficient CO2 photoreduction.
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| 32. |
- Zhao, Xi, et al.
(författare)
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Impacts of secondary ice production on Arctic mixed-phase clouds based on ARM observations and CAM6 single-column model simulations
- 2021
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Ingår i: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 21:7, s. 5685-5703
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Tidskriftsartikel (refereegranskat)abstract
- For decades, measured ice crystal number concentrations have been found to be orders of magnitude higher than measured ice-nucleating particle number concentrations in moderately cold clouds. This observed discrepancy reveals the existence of secondary ice production (SIP) in addition to the primary ice nucleation. However, the importance of SIP relative to primary ice nucleation remains highly unclear. Furthermore, most weather and climate models do not represent SIP processes well, leading to large biases in simulated cloud properties. This study demonstrates a first attempt to represent different SIP mechanisms (frozen raindrop shattering, ice ice collisional breakup, and rime splintering) in a global climate model (GCM). The model is run in the single column mode to facilitate comparisons with the Department of Energy (DOE) s Atmospheric Radiation Measurement (ARM) Mixed-Phase Arctic Cloud Experiment (MPACE) observations. We show the important role of SIP in four types of clouds during M-PACE (i.e., multilayer, single-layer stratus, transition, and frontal clouds), with the maximum enhancement in ice crystal number concentrations up to 4 orders of magnitude in moderately supercooled clouds. We reveal that SIP is the dominant source of ice crystals near the cloud base for the long-lived Arctic single-layer mixed-phase clouds. The model with SIP improves the occurrence and phase partitioning of the mixed-phase clouds, reverses the vertical distribution pattern of ice number concentrations, and provides a better agreement with observations. The findings of this study highlight the importance of considering SIP in GCMs.
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| 33. |
- Zhao, Xi, et al.
(författare)
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Important Ice Processes Are Missed by the Community Earth System Model in Southern Ocean Mixed-Phase Clouds : Bridging SOCRATES Observations to Model Developments
- 2023
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Ingår i: Journal of Geophysical Research: Atmospheres. - 2169-897X. ; 128:4
-
Tidskriftsartikel (refereegranskat)abstract
- Global climate models (GCMs) are challenged by difficulties in simulating cloud phase and cloud radiative effect over the Southern Ocean (SO). Some of the new-generation GCMs predict too much liquid and too little ice in mixed-phase clouds. This misrepresentation of cloud phase in GCMs results in weaker negative cloud feedback over the SO and a higher climate sensitivity. Based on a model comparison with observational data obtained during the Southern Ocean Cloud Radiation and Aerosol Transport Experimental Study, this study addresses a key uncertainty in the Community Earth System Model version 2 (CESM2) related to cloud phase, namely ice formation in pristine remote SO clouds. It is found that sea spray organic aerosols (SSOAs) are the most important type of ice nucleating particles (INPs) over the SO with concentrations 1 order of magnitude higher than those of dust INPs based on measurements and CESM2 simulations. Secondary ice production (SIP) which includes riming splintering, rain droplet shattering, and ice-ice collisional fragmentation as implemented in CESM2 is the dominant ice production process in moderately cold clouds with cloud temperatures greater than −20°C. SIP enhances the in-cloud ice number concentrations (Ni) by 1–3 orders of magnitude and predicts more mixed-phase (with percentage occurrence increased from 15% to 21%), in better agreement with the observations. This study highlights the importance of accurately representing the cloud phase over the pristine remote SO by considering the ice nucleation of SSOA and SIP processes, which are currently missing in most GCM cloud microphysics parameterizations.
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| 34. |
- Zhu, Gaoming, et al.
(författare)
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Synthesis and Properties of MoSi2–MoB–SiC Ceramics
- 2016
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Ingår i: Journal of The American Ceramic Society. - : Wiley. - 0002-7820 .- 1551-2916. ; 99:4, s. 1147-1150
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Tidskriftsartikel (refereegranskat)abstract
- MoB and SiC particulate reinforced MoSi2 matrix composites were synthesized in situ from Mo, Si, and B4C powder mixtures by self-propagating high-temperature synthesis (SHS). The SHS MoSi2–MoB–SiC products were vacuum hot-pressed (HPed) at 1400°C for 90 min to fabricate high-density (> 97.5% relative density) bulk composites. Microstructure refinement and improvements in the Vickers hardness and fracture toughness of the HPed composites were observed with increasing B4C content in the reaction mixture. The HPed composite of composition MoSi2–0.4MoB–0.1SiC exhibited grain size of 1–5 μm, Vickers hardness of 12.5 GPa, bending strength of 537 MPa, and fracture toughness of 3.8 MPa.m1/2. These excellent mechanical properties indicate that MoB and SiC particulate reinforced MoSi2 composites could be promising candidates for structural applications.
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| 35. |
- Zhu, Gengzheng, et al.
(författare)
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Targeting pattern-recognition receptors to discover new small molecule immune modulators
- 2018
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Ingår i: European Journal of Medicinal Chemistry. - Issy-les-Moulineaux : Elsevier Masson. - 0223-5234 .- 1768-3254. ; 144, s. 82-92
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Tidskriftsartikel (refereegranskat)abstract
- Pattern recognition receptors (PRRs) are key immune receptors of the innate immune system, which recognize the conserved pathogen-associated molecular patterns (PAMPs) of the invading pathogens. Compared to the adaptive immune receptors, PRRs have three distinguishing features, viz., universal expression, fast response and recognizing many kinds of microbes. Toll-like receptors (TLRs), RIG-I-like receptors (RLRs), C-type lectin receptors (CLRs) and NOD-like receptors (NLRs) recognize viral nucleic acid/bacterial fragments and trigger anti-microbial innate immune responses. Upon recognition of their ligand species, PRRs recruit specific intracellular adaptor proteins to initiate signaling pathways culminating in the activation of nuclear factor-κB (NF-κB), mitogen-activated protein (MAP) kinases and interferon regulatory factors (IRFs) that control the transcription of genes encoding pro-inflammatory factors including type I interferon and other inflammatory cytokines, which are critical for eliminating the potential threat to the host. Here, we summarize the effects of small molecule regulators acting on signaling pathways initiated by TLR, RLR and NLR as well as their influence on innate and adaptive immune responses leading to therapy. © 2017 Elsevier Masson SAS
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| 36. |
- Zody, Michael, 1968-, et al.
(författare)
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DNA sequence of human chromosome 17 and analysis of rearrangement in the human lineage
- 2006
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 440:7087, s. 1045-1049
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Tidskriftsartikel (refereegranskat)abstract
- Chromosome 17 is unusual among the human chromosomes in many respects. It is the largest human autosome with orthology to only a single mouse chromosome, mapping entirely to the distal half of mouse chromosome 11. Chromosome 17 is rich in protein-coding genes, having the second highest gene density in the genome. It is also enriched in segmental duplications, ranking third in density among the autosomes. Here we report a finished sequence for human chromosome 17, as well as a structural comparison with the finished sequence for mouse chromosome 11, the first finished mouse chromosome. Comparison of the orthologous regions reveals striking differences. In contrast to the typical pattern seen in mammalian evolution, the human sequence has undergone extensive intrachromosomal rearrangement, whereas the mouse sequence has been remarkably stable. Moreover, although the human sequence has a high density of segmental duplication, the mouse sequence has a very low density. Notably, these segmental duplications correspond closely to the sites of structural rearrangement, demonstrating a link between duplication and rearrangement. Examination of the main classes of duplicated segments provides insight into the dynamics underlying expansion of chromosome-specific, low-copy repeats in the human genome.
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