| 1. |
- Li, Junjie, et al.
(författare)
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A Novel Dry Selective Isotropic Atomic Layer Etching of SiGe for Manufacturing Vertical Nanowire Array with Diameter Less than 20 nm
- 2020
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Ingår i: Materials. - : MDPI AG. - 1996-1944. ; 13:3
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Tidskriftsartikel (refereegranskat)abstract
- Semiconductor nanowires have great application prospects in field effect transistors and sensors. In this study, the process and challenges of manufacturing vertical SiGe/Si nanowire array by using the conventional lithography and novel dry atomic layer etching technology. The final results demonstrate that vertical nanowires with a diameter less than 20 nm can be obtained. The diameter of nanowires is adjustable with an accuracy error less than 0.3 nm. This technology provides a new way for advanced 3D transistors and sensors.
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| 2. |
- Sampson, Joshua N., et al.
(författare)
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Analysis of Heritability and Shared Heritability Based on Genome-Wide Association Studies for 13 Cancer Types
- 2015
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Ingår i: Journal of the National Cancer Institute. - : Oxford University Press (OUP). - 0027-8874 .- 1460-2105. ; 107:12
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Tidskriftsartikel (refereegranskat)abstract
- Background: Studies of related individuals have consistently demonstrated notable familial aggregation of cancer. We aim to estimate the heritability and genetic correlation attributable to the additive effects of common single-nucleotide polymorphisms (SNPs) for cancer at 13 anatomical sites. Methods: Between 2007 and 2014, the US National Cancer Institute has generated data from genome-wide association studies (GWAS) for 49 492 cancer case patients and 34 131 control patients. We apply novel mixed model methodology (GCTA) to this GWAS data to estimate the heritability of individual cancers, as well as the proportion of heritability attributable to cigarette smoking in smoking-related cancers, and the genetic correlation between pairs of cancers. Results: GWAS heritability was statistically significant at nearly all sites, with the estimates of array-based heritability, h(l)(2), on the liability threshold (LT) scale ranging from 0.05 to 0.38. Estimating the combined heritability of multiple smoking characteristics, we calculate that at least 24% (95% confidence interval [CI] = 14% to 37%) and 7% (95% CI = 4% to 11%) of the heritability for lung and bladder cancer, respectively, can be attributed to genetic determinants of smoking. Most pairs of cancers studied did not show evidence of strong genetic correlation. We found only four pairs of cancers with marginally statistically significant correlations, specifically kidney and testes (rho = 0.73, SE = 0.28), diffuse large B-cell lymphoma (DLBCL) and pediatric osteosarcoma (rho = 0.53, SE = 0.21), DLBCL and chronic lymphocytic leukemia (CLL) (rho = 0.51, SE = 0.18), and bladder and lung (rho = 0.35, SE = 0.14). Correlation analysis also indicates that the genetic architecture of lung cancer differs between a smoking population of European ancestry and a nonsmoking Asian population, allowing for the possibility that the genetic etiology for the same disease can vary by population and environmental exposures. Conclusion: Our results provide important insights into the genetic architecture of cancers and suggest new avenues for investigation.
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| 3. |
- Chen, Peilin, et al.
(författare)
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Fabrication of a silver nanoparticle-coated collagen membrane with anti-bacterial and anti-inflammatory activities for guided bone regeneration
- 2018
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Ingår i: Biomedical materials. - 1748-6041. ; 13:6
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Tidskriftsartikel (refereegranskat)abstract
- Alveolar bone loss is a common problem that affects dental implant placement. A barrier between the bone substitute and gingiva that can prevent fibro-tissue ingrowth, bacterial infection and induce bone formation is a key factor in improving the success of alveolar ridge reconstruction. This study aims to develop a bioactive collagen barrier material for guided bone regeneration, that is coupled with anti-bacterial and anti-inflammatory properties. We have evaluated two silver coating methods and found controllable and precise coating achieved by sonication compared with sputtering. The optimized AgNP-coated collagen membrane exhibited excellent anti-bacterial effects against Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) with limited cellular toxicity. It also displayed effective anti-inflammatory effects by reducing the expression and release of inflammatory cytokines including IL-6 and TNF-alpha. Additionally, AgNP-coated collagen membranes were able to induce osteogenic differentiation of mesenchymal stem cells that guide bone regeneration. These findings demonstrate the potential application of AgNP-coated collagen membranes to prevent infection after bone graft introduction in alveolar ridge reconstruction.
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| 4. |
- Chen, Zhipeng, et al.
(författare)
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Design, Synthesis, and Structure-Activity Relationship of N-Aryl-N'-(thiophen-2-yl) thiourea Derivatives as Novel and Specific Human TLR1/2 Agonists for Potential Cancer Immunotherapy
- 2021
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Ingår i: Journal of Medicinal Chemistry. - Washington, DC : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 64:11, s. 7371-7389
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Tidskriftsartikel (refereegranskat)abstract
- The previous virtual screening of ten million compounds yielded two novel nonlipopeptide-like chemotypes as TLR2 agonists. Herein, we present the chemical optimization of our initial hit, 1-phenyl-3-(thiophen-2-yl) urea, which resulted in the identification of SMU-C80 (EC50 = 31.02 ± 1.01 nM) as a TLR2-specific agonist with a 370-fold improvement in bioactivity. Mechanistic studies revealed that SMU-C80, through TLR1/2, recruits the adaptor protein MyD88 and triggers the NF-κB pathway to release cytokines such as TNF-α and IL-1β from human, but not murine, cells. To the best of our knowledge, it is the first species-specific TLR1/2 agonist reported until now. Moreover, SMU-C80 increased the percentage of T, B, and NK cells ex vivo and activated the immune cells, which suppressed cancer cell growth in vitro. In summary, we obtained a highly efficient and specific human TLR1/2 agonist that acts through the MyD88 and NF-κB pathway, facilitating cytokine release and the simultaneous activation of immune cells that in turn affects the apoptosis of cancer cells. © 2021 American Chemical Society
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| 5. |
- He, Wei, et al.
(författare)
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China's Terrestrial Carbon Sink Over 2010–2015 Constrained by Satellite Observations of Atmospheric CO2 and Land Surface Variables
- 2022
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Ingår i: Journal of Geophysical Research: Biogeosciences. - 2169-8953. ; 127:2
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Tidskriftsartikel (refereegranskat)abstract
- The magnitude and distribution of China's terrestrial carbon sink remain uncertain due to insufficient constraints at large scales, whereby satellite data offer great potential for reducing the uncertainty. Here, we present two carbon sink estimates for China constrained either by satellite CO2 column concentrations (XCO2) within the Global Carbon Assimilation System or by remotely sensed soil moisture and Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) in addition to in situ CO2 observations within the Carbon Cycle Data Assimilation System. They point to a moderate size of carbon sinks of 0.34 ± 0.14 (mean ± unc.) and 0.43 ± 0.09 PgC/yr during 2010–2015, which are supported by an inventory-based estimate for forest and soil carbon sink (0.26 PgC/yr) and fall in the range of contemporary ensemble atmospheric inversions (0.25–0.48 PgC/yr). They also agree reasonably well on interannual variations, which reflect the carbon sink anomalies induced by regional droughts in southwest China. Furthermore, their spatial distributions are broadly consistent that of the forest inventory-based estimate, indicating that the largest carbon sinks locate in central and eastern China. Their estimates for forest carbon sink coincide fairly well with the inventory-based estimate across different regions, especially when aggregated to the north and south of China. Although enhanced recently by afforestation, China's carbon sink was also significantly weakened by regional droughts, which were often not fully represented in previous in situ CO2-based inversions due to insufficient observations. Our results suggest that satellite-based atmospheric CO2 and land surface observations are vital in characterizing terrestrial net carbon fluxes at regional scales.
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| 6. |
- Hu, Junjie, et al.
(författare)
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Flexibility Prediction of Aggregated Electric Vehicles and Domestic Hot Water Systems in Smart Grids
- 2021
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Ingår i: Engineering. - : Elsevier BV. - 2095-8099. ; 7:8, s. 1101-1114
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Tidskriftsartikel (refereegranskat)abstract
- With the growth of intermittent renewable energy generation in power grids, there is an increasing demand for controllable resources to be deployed to guarantee power quality and frequency stability. The flexibility of demand response (DR) resources has become a valuable solution to this problem. However, existing research indicates that problems on flexibility prediction of DR resources have not been investigated. This study applied the temporal convolution network (TCN)-combined transformer, a deep learning technique to predict the aggregated flexibility of two types of DR resources, that is, elec-tric vehicles (EVs) and domestic hot water system (DHWS). The prediction uses historical power con-sumption data of these DR resources and DR signals (DSs) to facilitate prediction. The prediction can generate the size and maintenance time of the aggregated flexibility. The accuracy of the flexibility pre-diction results was verified through simulations of case studies. The simulation results show that under different maintenance times, the size of the flexibility changed. The proposed DR resource flexibility pre-diction method demonstrates its application in unlocking the demand-side flexibility to provide a reserve to grids.
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| 7. |
- Li, Junjie, 1995, et al.
(författare)
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High frequency noise characterisation of graphene field-effect transistors at different temperatures
- 2019
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Graphene is a promising material for high frequency electronics applications thanks to its intrinsically high carrier mobility and velocity, and graphene transistors are continuously pushed toward higher operating frequencies [1]. For high frequency low noise amplifiers, it is important to evaluate the noise parameters of the graphene field-effect transistors (GFETs). In this work, we present the noise performance of the GFETs made of chemical vapour deposition (CVD) in the frequency and temperature ranges of 2-18 GHz and -60-25 C. The noise figure with 50 Ohm impedance termination (F50) was measured using the cold-source method and then the minimum noise figure (Fmin) was estimated using the Pospieszalski’s noise model [2, 3]. In Fig. 1 and Fig. 2, the Fmin of a GFET with a gate length of 0.5 μm as a function of the frequency (f) and drain voltage (Vd) at different temperatures are shown. This GFET revealed maximum frequency of oscillation (fmax) of 18 and 21 GHz at 25 and -60 °C, respectively. It can be seen from Fig. 1, that the Fmin at 8 GHz is approx. 2 dB lower than that of the previously published CVD GFETs and comparable with that of the best published SiC GFETs [4, 5]. The Fmin decreases significantly with temperature down to 0.3 dB at 8 GHz, competing with Si CMOS [6]. It can be seen from Fig. 2, that Fmin decreases with the Vd and saturates above approx. 1 V, where GFETs operate in the velocity saturation mode [1]. Analysis of the dependences allows for further development of the GFETs for advanced low noise amplifiers.
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| 8. |
- Li, Qing, et al.
(författare)
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Hierarchical Dehydrogenation Reactions on a Copper Surface
- 2018
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Ingår i: Journal of the American Chemical Society. - : AMER CHEMICAL SOC. - 0002-7863 .- 1520-5126. ; 140:19, s. 6076-6082
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Tidskriftsartikel (refereegranskat)abstract
- Hierarchical control of chemical reactions is being considered as one of the most ambitious and challenging topics in modern organic chemistry. In this study, we have realized the one-by-one scission of the X-H bonds (X = N and C) of aromatic amines in a controlled fashion on the Cu(lll) surface. Each dehydrogenation reaction leads to certain metal-organic supramolecular structures, which were monitored in single-bond resolution via scanning tunneling microscopy and noncontact atomic force microscopy. Moreover, the reaction pathways were elucidated from X-ray photoelectron spectroscopy measurements and density functional theory calculations. Our insights pave the way for connecting molecules into complex structures in a more reliable and predictable manner, utilizing carefully tuned stepwise on-surface synthesis protocols.
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| 9. |
- Liu, Huizeng, et al.
(författare)
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Estimating ultraviolet reflectance from visible bands in ocean colour remote sensing
- 2021
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Ingår i: Remote Sensing of Environment. - : Elsevier BV. - 0034-4257 .- 1879-0704. ; 258
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, ultraviolet (UV) bands have received increasing attention from the ocean colour remote sensing community, as they may contribute to improving atmospheric correction and inherent optical properties (IOPs) retrieval. However, most ocean colour satellite sensors do not have UV bands, and the accurate retrieval of UV remote sensing reflectance (Rrs) from UV satellite data is still a challenge. In order to address this problem, this study proposes a hybrid approach for estimating UV Rrs from the visible bands. The approach was implemented with two popular ocean colour satellite sensors, i.e. GCOM-C SGLI and Sentinel-3 OLCI. In situ Rrs collected globally and simulated Rrs spectra were used to develop UV Rrs retrieval models, and UV Rrs values at 360, 380 and 400 nm were estimated from visible Rrs spectra. The performances of the established models were evaluated using in situ Rrs and satellite data, and applied to a semi-analytical algorithm for IOPs retrieval. The results showed that: (i) UV Rrs retrieval models had low uncertainties with mean absolute percentage differences (MAPD) less than 5%; (ii) the model assessment with in situ Rrs showed high accuracy (r = 0.92–1.00 and MAPD = 1.11%–10.95%) in both clear open ocean and optically complex waters; (iii) the model assessment with satellite data indicated that model-estimated UV Rrs were more consistent with in situ values than satellite-derived UV Rrs; and (iv) model-estimated UV Rrs may improve the decomposition accuracy of absorption coefficients in semi-analytical IOPs algorithm. Thus, the proposed method has great potentials for reconstructing UV Rrs data and improving IOPs retrieval for historical satellite sensors, and might also be useful for UV-based atmospheric correction algorithms.
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| 10. |
- Niu, Guoxiang, et al.
(författare)
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Nitrogen addition and mowing had only weak interactive effects on macronutrients in plant-soil systems of a typical steppe in Inner Mongolia
- 2023
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Ingår i: Journal of Environmental Management. - 0301-4797. ; 347
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Tidskriftsartikel (refereegranskat)abstract
- Effective management of macronutrients is pivotal in the optimization and provisioning of ecosystem services in grassland areas, particularly in degraded grasslands. In such instances where mowing and nitrogen (N) fertilization have emerged as predominant management strategies, nutrient management is especially important. However, the precise effects of these concurrent practices on the distribution of macronutrients in plant-soil systems remain unclear. Here we evaluated the effects of 12 years of N addition (2, 10, and 50 g N m−2 year−1) and mowing on the concentrations and pools of six macronutrients (i.e., N; phosphorus P; sulfur S, calcium Ca, magnesium Mg, and potassium K) in three plant components (aboveground plants, litter, and belowground roots) at the community level and in the soil in a typical steppe in Inner Mongolia. Our results revealed that N addition generally raised the N concentration in the entire plant-soil system, regardless of whether plots were mowed. Higher N addition (10 and 50 g N m−2 year−1) also led to higher concentrations of P (+22%, averaging two N addition rates), S (+16%), K (+22%), Ca (+22%), and Mg (+24%) in plants but lower concentrations of these nutrients in the litter. Similar decreases in K (−9%), Ca (−46%), and Mg (−8%) were observed in the roots. In light of the observed increases in vegetation biomass and the lack of pronounced changes in soil bulk density, we found that the ecosystem N enrichment resulted in increased pools of all measured macronutrients in plants, litter, and roots (with the exception of Ca in the roots) while concurrently decreased the pools of P (−20%, averaging two higher N addition rates), S (−12%), K (−10%), Ca (−37%), and Mg (−19%) in the soil, with no obvious effect of the mowing practice. Overall, mowing exhibited a very limited capacity to alleviate the effects of long-term N addition on macronutrients in the plant-soil system. These findings highlight the importance of considering the distribution of macronutrients across distinct plant organs and the dynamic nutrient interplay between plants and soil, particularly in the context of long-term fertilization and mowing practices, when formulating effective grassland management strategies.
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