1. |
- Wang, Zhaoming, et al.
(författare)
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Imputation and subset-based association analysis across different cancer types identifies multiple independent risk loci in the TERT-CLPTM1L region on chromosome 5p15.33
- 2014
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 23:24, s. 6616-6633
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Tidskriftsartikel (refereegranskat)abstract
- Genome-wide association studies (GWAS) have mapped risk alleles for at least 10 distinct cancers to a small region of 63 000 bp on chromosome 5p15.33. This region harbors the TERT and CLPTM1L genes; the former encodes the catalytic subunit of telomerase reverse transcriptase and the latter may play a role in apoptosis. To investigate further the genetic architecture of common susceptibility alleles in this region, we conducted an agnostic subset-based meta-analysis (association analysis based on subsets) across six distinct cancers in 34 248 cases and 45 036 controls. Based on sequential conditional analysis, we identified as many as six independent risk loci marked by common single-nucleotide polymorphisms: five in the TERT gene (Region 1: rs7726159, P = 2.10 × 10(-39); Region 3: rs2853677, P = 3.30 × 10(-36) and PConditional = 2.36 × 10(-8); Region 4: rs2736098, P = 3.87 × 10(-12) and PConditional = 5.19 × 10(-6), Region 5: rs13172201, P = 0.041 and PConditional = 2.04 × 10(-6); and Region 6: rs10069690, P = 7.49 × 10(-15) and PConditional = 5.35 × 10(-7)) and one in the neighboring CLPTM1L gene (Region 2: rs451360; P = 1.90 × 10(-18) and PConditional = 7.06 × 10(-16)). Between three and five cancers mapped to each independent locus with both risk-enhancing and protective effects. Allele-specific effects on DNA methylation were seen for a subset of risk loci, indicating that methylation and subsequent effects on gene expression may contribute to the biology of risk variants on 5p15.33. Our results provide strong support for extensive pleiotropy across this region of 5p15.33, to an extent not previously observed in other cancer susceptibility loci.
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2. |
- Machiela, Mitchell J., et al.
(författare)
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Characterization of Large Structural Genetic Mosaicism in Human Autosomes
- 2015
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Ingår i: American Journal of Human Genetics. - : Elsevier BV. - 0002-9297 .- 1537-6605. ; 96:3, s. 487-497
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Tidskriftsartikel (refereegranskat)abstract
- Analyses of genome-wide association study (GWAS) data have revealed that detectable genetic mosaicism involving large (>2 Mb) structural autosomal alterations occurs in a fraction of individuals. We present results for a set of 24,849 genotyped individuals (total GWAS set II [TGSII]) in whom 341 large autosomal abnormalities were observed in 168 (0.68%) individuals. Merging data from the new TGSII set with data from two prior reports (the Gene-Environment Association Studies and the total GWAS set I) generated a large dataset of 127,179 individuals; we then conducted a meta-analysis to investigate the patterns of detectable autosomal mosaicism (n = 1,315 events in 925 [0.73%] individuals). Restricting to events >2 Mb in size, we observed an increase in event frequency as event size decreased. The combined results underscore that the rate of detectable mosaicism increases with age (p value = 5.5 x 3 10(-31)) and is higher in men (p value = 0.002) but lower in participants of African ancestry (p value = 0.003). In a subset of 47 individuals from whom serial samples were collected up to 6 years apart, complex changes were noted over time and showed an overall increase in the proportion of mosaic cells as age increased. Our large combined sample allowed for a unique ability to characterize detectable genetic mosaicism involving large structural events and strengthens the emerging evidence of non-random erosion of the genome in the aging population.
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3. |
- Machiela, Mitchell J, et al.
(författare)
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Female chromosome X mosaicism is age-related and preferentially affects the inactivated X chromosome
- 2016
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Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- To investigate large structural clonal mosaicism of chromosome X, we analysed the SNP microarray intensity data of 38,303 women from cancer genome-wide association studies (20,878 cases and 17,425 controls) and detected 124 mosaic X events >2 Mb in 97 (0.25%) women. Here we show rates for X-chromosome mosaicism are four times higher than mean autosomal rates; X mosaic events more often include the entire chromosome and participants with X events more likely harbour autosomal mosaic events. X mosaicism frequency increases with age (0.11% in 50-year olds; 0.45% in 75-year olds), as reported for Y and autosomes. Methylation array analyses of 33 women with X mosaicism indicate events preferentially involve the inactive X chromosome. Our results provide further evidence that the sex chromosomes undergo mosaic events more frequently than autosomes, which could have implications for understanding the underlying mechanisms of mosaic events and their possible contribution to risk for chronic diseases.
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4. |
- 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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5. |
- Chi, Xiaoming, et al.
(författare)
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Fractal superconducting nanowire single-photon detectors with reduced polarization sensitivity
- 2018
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Ingår i: Optics Letters. - : OPTICAL SOC AMER. - 0146-9592 .- 1539-4794. ; 43:20, s. 5017-5020
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate superconducting nanowire single-photon detectors (SNSPDs) based on a fractal design of the nanowires to reduce the polarization sensitivity of detection efficiency. We patterned niobium titanium nitride thin films into Peano curves with a linewidth of 100 nm and integrated the nanowires with optical microcavities to enhance their optical absorption. At a base temperature of 2.6 K, the fractal SNSPD exhibited a polarization-maximum device efficiency of 67% and a polarization-minimum device efficiency of 61% at a wavelength of 1550 nm. Therefore, the polarization sensitivity, defined as their ratio, was 1.1, lower than the polarization sensitivity of the SNSPDs in the meander design. The reduced polarization sensitivity of the detector could be maintained for higher-order spatial modes in multimode optical fibers and could tolerate misalignment between the optical mode and the detector. This fractal design is applicable to both amorphous and polycrystalline materials that are commonly used for making SNSPDs.
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6. |
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7. |
- Feng, Yifan, et al.
(författare)
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Fractal Superconducting Nanowire Single-Photon Detectors and Their Applications in Imaging
- 2022
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Ingår i: Proceedings of the 2022 Conference on Lasers and Electro-Optics Pacific Rim, CLEO/PR 2022. - : Optica Publishing Group.
-
Konferensbidrag (refereegranskat)abstract
- We present our research on fractal superconducting nanowire single-photon detectors and their applications in light detection and ranging (LiDAR), full-Stokes polarimetric imaging, and non-line-of-sight imaging.
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8. |
- Feng, Yifan, et al.
(författare)
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Fractal Superconducting Nanowire Single-Photon Detectors and Their Applications in Imaging
- 2022
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Ingår i: 2022 Conference on Lasers and Electro-Optics Pacific Rim, CLEO-PR 2022 - Proceedings. - : Institute of Electrical and Electronics Engineers Inc..
-
Konferensbidrag (refereegranskat)abstract
- We present our research on fractal superconducting nanowire single-photon detectors and their applications in light detection and ranging (LiDAR), full-Stokes polarimetric imaging, and non-line-of-sight imaging.
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9. |
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10. |
- Hu, Nan, et al.
(författare)
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Full-Stokes polarimetric measurements and imaging using a fractal superconducting nanowire single-photon detector
- 2022
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Ingår i: Optica. - : Optica Publishing Group. - 2334-2536. ; 9:4, s. 346-351
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Tidskriftsartikel (refereegranskat)abstract
- Measuring the states of polarization (SoP) of light is fundamentally important for applications ranging from communication, sensing, spectroscopy, imaging, to navigation. Superconducting nanowire single-photon detectors (SNSPDs) are ideal detectors of choice for faint-light detection and measurements, but SNSPDs themselves cannot resolve the SoP of photons. Here, based on a fractal SNSPD, we demonstrate a full-Stokes polarimetric measurement system that can measure arbitrary SoP of faint light. The measured SoPs are in excellent agreement with those of a state-of-the-art commercial polarimeter, but the sensitivity of our system reaches -86.6 dBm, which is 26.6 dB better than that of the commercial counterpart. As a direct application, we further demonstrate remote polarimetric imaging (i.e., polarimetric LiDAR) with a complete set of polarimetric contrast.
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11. |
- Hu, Nan, et al.
(författare)
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Photon-Counting LIDAR Based on a Fractal SNSPD
- 2021
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Ingår i: 2021 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXPOSITION (OFC). - : IEEE.
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Konferensbidrag (refereegranskat)abstract
- We report on a photon-counting LIDAR system based on a polarization-insensitive fractal SNSPD with high detection efficiency and high timing resolution, and showcase depth imaging of an object at 1560 nm with millimeter depth resolution.
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12. |
- Hu, Xiaolong, et al.
(författare)
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Fractal superconducting nanowire single-photon detectors and their applications in polarimetric imaging
- 2024
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Ingår i: Advanced Photon Counting Techniques XVIII. - : SPIE-Intl Soc Optical Eng.
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Konferensbidrag (refereegranskat)abstract
- In this paper, we review the research and development of the fractal superconducting nanowire single-photon detectors (SNSPDs), including our demonstrations of high-performance devices and systems with over 80% system detection efficiency, negligibly low residual polarization sensitivity, and low timing jitter. Using the fractal SNSPDs, we demonstrate full-Stokes polarimetric imaging LiDAR.
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13. |
- Hu, Xiaolong, et al.
(författare)
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Superconducting nanowire single-photon detectors at the infrared spectrum range : detection efficiency and timing jitter
- 2019
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Ingår i: TERAHERTZ, RF, MILLIMETER, AND SUBMILLIMETER-WAVE TECHNOLOGY AND APPLICATIONS XII. - : SPIE. - 9781510624771
-
Konferensbidrag (refereegranskat)abstract
- This paper reviews some recent research progress in superconducting nanowire single-photon detectors (SNSPDs) at the infrared spectrum range, with particular emphasis on detection efficiency and timing jitter. For detection efficiency, we present fractal SNSPDs with reduced polarization sensitivity; for timing jitter, we present two mechanisms of device timing jitter - vortex-crossing-induced timing jitter and spatial-inhomogeneity-induced timing jitter.
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14. |
- Hu, Xiaolong, et al.
(författare)
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Timing properties of superconducting nanowire single-photon detectors
- 2019
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Ingår i: Quantum Optics and Photon Counting 2019. - : SPIE - International Society for Optical Engineering. - 9781510627215
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Konferensbidrag (refereegranskat)abstract
- In this paper, we review theoretical and experimental research progress on timing properties of superconducting nanowire single-photon detectors, including six possible mechanisms that induce timing jitter and experiments towards ultra-low timing jitter.
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15. |
- Jacobs, Kevin B, et al.
(författare)
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Detectable clonal mosaicism and its relationship to aging and cancer.
- 2012
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Ingår i: Nature Genetics. - New York : Nature Publishing Group. - 1061-4036 .- 1546-1718. ; 44:6, s. 651-658
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Tidskriftsartikel (refereegranskat)abstract
- In an analysis of 31,717 cancer cases and 26,136 cancer-free controls from 13 genome-wide association studies, we observed large chromosomal abnormalities in a subset of clones in DNA obtained from blood or buccal samples. We observed mosaic abnormalities, either aneuploidy or copy-neutral loss of heterozygosity, of >2 Mb in size in autosomes of 517 individuals (0.89%), with abnormal cell proportions of between 7% and 95%. In cancer-free individuals, frequency increased with age, from 0.23% under 50 years to 1.91% between 75 and 79 years (P = 4.8 × 10(-8)). Mosaic abnormalities were more frequent in individuals with solid tumors (0.97% versus 0.74% in cancer-free individuals; odds ratio (OR) = 1.25; P = 0.016), with stronger association with cases who had DNA collected before diagnosis or treatment (OR = 1.45; P = 0.0005). Detectable mosaicism was also more common in individuals for whom DNA was collected at least 1 year before diagnosis with leukemia compared to cancer-free individuals (OR = 35.4; P = 3.8 × 10(-11)). These findings underscore the time-dependent nature of somatic events in the etiology of cancer and potentially other late-onset diseases.
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16. |
- Meng, Yun, et al.
(författare)
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Fractal Superconducting Nanowires Detect Infrared Single Photonswith 84% System Detection Efficiency, 1.02 Polarization Sensitivity,and 20.8 ps Timing Resolution br
- 2022
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Ingår i: ACS Photonics. - : American Chemical Society (ACS). - 2330-4022. ; 9:5, s. 1547-1553
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Tidskriftsartikel (refereegranskat)abstract
- The near-unity system detection efficiency (SDE) and excellent timing resolution of superconducting nanowiresingle-photon detectors (SNSPDs), combined with their other merits, have enabled many classical and quantum photonicapplications. However, the prevalent design based on meandering nanowires makes SDE dependent on the polarization states of theincident photons; for unpolarized light, the major merit of high SDE would get compromised, which could be detrimental to photon-starved applications. Here, we create SNSPDs with an arced fractal geometry that almost completely eliminates this polarizationdependence of the SDE, and we experimentally demonstrate 84 +/- 3% SDE, 1.02-0.02+0.06polarization sensitivity at the wavelength of1575 nm, and 20.8 ps timing jitter in a 0.1 W closed-cycle Gifford-McMahon cryocooler, at the base temperature of 2.0 K. Thisdemonstration provides a novel, practical device structure of SNSPDs, allowing for operation in the visible, near-infrared, and mid-infrared spectral ranges, and paves the way for polarization-insensitive single-photon detection with high SDE and high timingresolution.
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17. |
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18. |
- Yang, Mei Jie, et al.
(författare)
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Expression and activity of critical digestive enzymes during early larval development of the veined rapa whelk, Rapana venosa (Valenciennes, 1846)
- 2020
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Ingår i: Aquaculture. - : Elsevier BV. - 0044-8486. ; 519
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Tidskriftsartikel (refereegranskat)abstract
- Metamorphosis is a vital developmental event in the life cycle of molluscs and involves extensive morphological and physiological changes. Remodeling of the digestive system is suggested to occur anticipatorily to enable the larva to shift its diet (from filter feeding on microalgae to feeding on small bivalves) after metamorphosis. Changes in the profiles and activities of digestive enzymes, the main executors of digestion, can reflect substantial remodeling of the digestive system. Artificial aquaculture of Rapana venosa, an important commercial shellfish in China, has been hampered because the transition of its food habit during metamorphosis makes determining the timing and dose for bait regulation difficult. In the present study, full-length cDNA sequences encoding cellulase and trypsin were characterized, and cellulase and trypsin mRNA expression levels were analyzed. Additionally, patterns in the activities of six digestive enzymes, including trypsin and cellulase, were investigated throughout the early developmental stage of R. venosa. In the present study, the full-length cDNA of the cellulase gene, comprising 2,086 bp, was found to contain a 1,719-bp open reading frame encoding 572 amino acids, and the full-length cDNA of the trypsin gene was found to be 1,587 bp in length and contained an 855-bp open reading frame encoding 284 amino acids. Quantitative real-time PCR showed that the cellulase levels in R. venosa increased beginning at the early intramembrane veliger stage, whereas cellulase activity was significantly increased in the one-spiral whorl stage. The mRNA expression and activity of trypsin were greatly increased in the juvenile stage (postlarva), whereas those of cellulase were decreased during this stage, which indicated functional changes in the digestive system during larval food habit transition. Our results showed that remodeling of the digestive system occurs prior to metamorphosis and suggest that animal bait should be provided as early as possible to R. venosa in the four-spiral whorl stage to meet its nutritional requirements for the development of its digestive system and to ensure successful metamorphosis of competent larvae.
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19. |
- Yu, Zheng Lin, et al.
(författare)
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Environmental water flow can boost foraging success of the juvenile rapa whelk Rapana venosa (Muricidae) in aquaculture tanks with still or flowing water : Indication of chemosensory foraging
- 2019
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Ingår i: Aquaculture. - : Elsevier BV. - 0044-8486. ; 513
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Tidskriftsartikel (refereegranskat)abstract
- Artificial breeding of Rapana venosa has been attempted in China, but the high mortality rate of rapa whelk juveniles (10–40 mm) seriously restricts the breeding success of this species in artificial cultivation and the overall aquaculture industry, and thus the scale of industrialization is far from being realized. One main factor was found to contribute to this high mortality rate: the low predation efficiency of juveniles. We studied the foraging behavior of various sized R. venosa juveniles in still, flowing, and circulating water, with the juveniles being positioned either upstream or downstream from the prey in the flowing water experiments. Our findings demonstrated that the distance between juveniles and prey in still water significantly restricted the ability of juveniles to locate food, but water flow significantly enhanced this ability. In addition, the small-sized juveniles were found to be more active predators than the larger sized juveniles. Our findings demonstrated that circulating water flow is important to improve the survival and growth rate of juveniles in R. venosa cultures. Our results broaden the understanding of chemical orientation in gastropods and can be used to develop or improve commercial breeding strategies for R. venosa.
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20. |
- Zou, Kai, et al.
(författare)
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Fractal superconducting nanowire single-photon detectors working in dual bands and their applications in free-space and underwater hybrid LIDAR
- 2023
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Ingår i: Optics Letters. - : Optica Publishing Group. - 0146-9592 .- 1539-4794. ; 48:2, s. 415-418
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate a fiber-coupled fractal superconducting nanowire single-photon detector (SNSPD) system with minimum polarization dependence of detection efficiency. Its system detection efficiency (SDE) was maximized at the wavelength of 1540 nm, which was measured to be 91 +/- 4%; furthermore, we observed the second local maximum of SDE at the wavelength of 520 nm, which was measured to be 61 +/- 2%. This dual-band feature of SDE was due to the enhancement of the optical absorptance by two longitudinal resonance modes of the micro-cavity. By using high SDE with minimum polarization dependence in these two bands, we implemented a hybrid LIDAR for imaging the remote objects in free space and under water.
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21. |
- Zou, Kai, et al.
(författare)
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Superconducting Nanowire Single-Photon Detectors and Multi-Photon Detectors
- 2022
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Ingår i: Optics InfoBase Conference Papers. - : Optica Publishing Group (formerly OSA).
-
Konferensbidrag (refereegranskat)abstract
- We present our research progress in superconducting nanowire single-photon detectors (SNSPDs) and multi-photon detectors (SNMPDs), including fractal SNSPDs with reduced polarization sensitivity, two mechanisms of device timing jitter, and SNMPDs integrated with current reservoirs.
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22. |
- Björnerås, Caroline, et al.
(författare)
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Inland blue holes of The Bahamas - chemistry and biology in a unique aquatic environment
- 2020
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Ingår i: Fundamental and Applied Limnology. - : Schweizerbart science publishers. - 1863-9135. ; 194:2, s. 95-106
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Tidskriftsartikel (refereegranskat)abstract
- While lake systems in temperate regions have been extensively studied, tropical and subtropical systems have received less attention. Here, we describe the water chemistry and biota of ten inland blue holes on Andros Island, The Bahamas, representative of the morphological, abiotic, and biotic variation among Androsian inland blue holes. The majority of the studied blue holes were vertically stratified with oxic freshwater overlying anoxic saline groundwater of marine origin. Water chemistry (e.g. total phosphorus and nitrogen) in shallow waters was similar among blue holes, while turbidity and water color varied. Presence of hydrogen sulfide and reduced iron in and below the halocline indicate reducing conditions in all stratified blue holes. The biota above the halocline was also similar among blue holes with a few taxa dominating the phytoplankton community, and the zooplankton community consisting of copepods and rotifers. The Bahamas mosquitofish (Gambusia hubbsi) was present in all investigated blue holes, often accompanied by other small planktivorous fish, while the piscivorous bigmouth sleeper (Gobiomorus donnitor) was only present in some of the blue holes. Our field study reinforces that inland blue holes are highly interesting for biogeochemical research, and provide naturally replicated systems for evolutionary studies.
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23. |
- Chen, Gang, et al.
(författare)
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EDF-VD Scheduling of Flexible Mixed-Criticality System With Multiple-Shot Transitions
- 2018
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Ingår i: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems. - 0278-0070 .- 1937-4151. ; 37:11, s. 2393-2403
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Tidskriftsartikel (refereegranskat)abstract
- The existing mixed-criticality (MC) real-time task models assume that once any high-criticality task overruns, all high-criticality jobs execute up to their most pessimistic WCET estimations simultaneously in a one-shot manner. This is very pessimistic in the sense of unnecessary resource overbooking. In this paper, we propose a more generalized mixed-critical real-time task model, called flexible MC model with multiple-shot transitions (FMC-MST), to address this problem. In FMC-MST, high-criticality tasks can transit multiple intermediate levels to handle less pessimistic overruns independently and to nonuni-formly scale the deadline on each level. We develop a run-time schedulability analysis for FMC-MST under EDF-VD scheduling, in which a better tradeoff between the penalties of low-criticality tasks and the overruns of high-criticality tasks is achieved to improve the service quality of low-criticality tasks. We also develop a resource optimization technique to find resource-efficient level-insertion configurations for FMC-MST task systems under MC timing constraints. Experiments demonstrate the effectiveness of FMC-MST compared with the state-of-the-art techniques.
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24. |
- Deng, Min, et al.
(författare)
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Genome-wide association analyses in Han Chinese identify two new susceptibility loci for amyotrophic lateral sclerosis
- 2013
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Ingår i: Nature Genetics. - : Nature Publishing Group. - 1061-4036 .- 1546-1718. ; 45:6, s. 697-
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Tidskriftsartikel (refereegranskat)abstract
- To identify susceptibility genes for amyotrophic lateral sclerosis (ALS), we conducted a genome-wide association study (GWAS) in 506 individuals with sporadic ALS and 1,859 controls of Han Chinese ancestry. Ninety top SNPs suggested by the current GWAS and 6 SNPs identified by previous GWAS were analyzed in an independent cohort of 706 individuals with ALS and 1,777 controls of Han Chinese ancestry. We discovered two new susceptibility loci for ALS at 1q32 (CAMK1G, rs6703183, P-combined = 2.92 x 10(-8), odds ratio (OR) = 1.31) and 22p11 (CABIN1 and SUSD2, rs8141797, P-combined = 2.35 x 10(-9), OR = 1.52). These two loci explain 12.48% of the overall variance in disease risk in the Han Chinese population. We found no association evidence for the previously reported loci in the Han Chinese population, suggesting genetic heterogeneity of disease susceptibility for ALS between ancestry groups. Our study identifies two new susceptibility loci and suggests new pathogenic mechanisms of ALS.
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25. |
- Ding, Shaozhen, et al.
(författare)
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novoPathFinder: a webserver of designing novel-pathway with integrating GEM-model
- 2020
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Ingår i: Nucleic Acids Research. - : Oxford University Press (OUP). - 0305-1048 .- 1362-4962. ; 48:W1, s. W477-W487
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Tidskriftsartikel (refereegranskat)abstract
- To increase the number of value-added chemicals that can be produced by metabolic engineering and synthetic biology, constructing metabolic space with novel reactions/pathways is crucial. However, with the large number of reactions that existed in the metabolic space and complicated metabolisms within hosts, identifying novel pathways linking two molecules or heterologous pathways when engineering a host to produce a target molecule is an arduous task. Hence, we built a user-friendly web server, novoPathFinder, which has several features: (i) enumerate novel pathways between two specified molecules without considering hosts; (ii) construct heterologous pathways with known or putative reactions for producing target molecule within Escherichia coli or yeast without giving precursor; (iii) estimate novel pathways with considering several categories, including enzyme promiscuity, Synthetic Complex Score (SCScore) and LD50 of intermediates, overall stoichiometric conversions, pathway length, theoretical yields and thermodynamic feasibility. According to the results, novoPathFinder is more capable to recover experimentally validated pathways when comparing other rule-based web server tools. Besides, more efficient pathways with novel reactions could also be retrieved for further experimental exploration. novoPathFinder is available at http://design.rxnfinder.org/novopathfinder/.
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26. |
- Gao, Yun, et al.
(författare)
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Region separation type bio-photoelectrode based all-solid-state self-powered aptasensor for ochratoxin A and aflatoxin B1 detection
- 2022
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Ingår i: Sensors and actuators. B, Chemical. - : Elsevier. - 0925-4005 .- 1873-3077. ; 364
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Tidskriftsartikel (refereegranskat)abstract
- Ochratoxin A (OTA) and Aflatoxin B1 (AFB1) are two highly toxic and naturally coexistence mycotoxins, which have posed a serious threat to food safety. The coexistence of these two mycotoxins can produce significant synergistic effects, so it is necessary to establish an effective analytical method. In this work, a dual biophotoelectrode based all-solid-state multiplexed self-powered aptasensor was realized for high-throughput analysis of OTA and AFB1. There was a large Fermi level difference between photoanode and photocathode, which ensured the light assisted self-driving of the system. Due to the regional immobilization of aptamers, it could save the dosage of recognition elements, reduce the preparation cost and simplify the operation procedure. Meanwhile, construction strategy of spatial separation could effectively eliminate the overlapping signals and cross interference between targets, achieving the results more accurate and the calculation more convenient. The constructed aptasensor realized OTA and AFB1 detection in corn samples with practicality, good stability, antiinterference ability and repeatability. Therefore, this work not only achieved the high-throughput analysis of mycotoxins, but also provided a new perspective for the construction of all-solid-state multiplexed self-powered sensor.
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27. |
- Ge, Yue, et al.
(författare)
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Environmental OMICS: Current Status and Future Directions
- 2013
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Ingår i: JOURNAL OF INTEGRATED OMICS. - : Proteomass Scientific Society. - 2182-0287. ; 3:2, s. 75-87
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Tidskriftsartikel (refereegranskat)abstract
- Applications of OMICS to high throughput studies of changes of genes, RNAs, proteins, metabolites, and their associated functionsin cells or organisms exposed to environmental chemicals has led to the emergence of a very active research field: environmental OMICS.This developing field holds an important key for improving the scientific basis for understanding the potential impacts of environmentalchemicals on both health and the environment. Here we describe the state of environmental OMICS with an emphasis on its recent accomplishmentsand its problems and potential solutions to facilitate the incorporation of OMICS into mainstream environmental and healthresearch.Data sources: We reviewed relevant and recently published studies on the applicability and usefulness of OMICS technologies to the identificationof toxicity pathways, mechanisms, and biomarkers of environmental chemicals for environmental and health risk monitoring andassessment, including recent presentations and discussions on these issues at The First International Conference on Environmental OMICS(ICEO), held in Guangzhou, China during November 8-12, 2011. This paper summarizes our review.Synthesis: Environmental OMICS aims to take advantage of powerful genomics, transcriptomics, proteomics, and metabolomics tools toidentify novel toxicity pathways/signatures/biomarkers so as to better understand toxicity mechanisms/modes of action, to identify/categorize/prioritize/screen environmental chemicals, and to monitor and predict the risks associated with exposure to environmental chemicalson human health and the environment. To improve the field, some lessons learned from previous studies need to be summarized, aresearch agenda and guidelines for future studies need to be established, and a focus for the field needs to be developed.Conclusions: OMICS technologies for identification of RNA, protein, and metabolic profiles and endpoints have already significantly improvedour understanding of how environmental chemicals affect our ecosystem and human health. OMICS breakthroughs are empoweringthe fields of environmental toxicology, chemical toxicity characterization, and health risk assessment. However, environmental OMICS is stillin the data generation and collection stage. Important data gaps in linking and/or integrating toxicity data with OMICS endpoints/profilesneed to be filled to enable understanding of the potential impacts of chemicals on human health and the environment. It is expected thatfuture environmental OMICS will focus more on real environmental issues and challenges such as the characterization of chemical mixturetoxicity, the identification of environmental and health biomarkers, and the development of innovative environmental OMICS approachesand assays. These innovative approaches and assays will inform chemical toxicity testing and prediction, ecological and health risk monitoringand assessment, and natural resource utilization in ways that maintain human health and protects the environment in a sustainable manner.
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28. |
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29. |
- Han, Mengying, et al.
(författare)
-
ChemHub: a knowledgebase of functional chemicals for synthetic biology studies
- 2021
-
Ingår i: Bioinformatics. - : Oxford University Press (OUP). - 1367-4803 .- 1367-4811 .- 1460-2059. ; 37:22, s. 4275-4276
-
Tidskriftsartikel (refereegranskat)abstract
- The field of synthetic biology lacks a comprehensive knowledgebase for selecting synthetic target molecules according to their functions, economic applications and known biosynthetic pathways. We implemented ChemHub, a knowledgebase containing >90 000 chemicals and their functions, along with related biosynthesis information for these chemicals that was manually extracted from >600 000 published studies by more than 100 people over the past 10 years.
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30. |
- He, Nan, et al.
(författare)
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High-Speed Duplex Free Space Optical Communication System Assisted by a Wide-Field-of-View Metalens
- 2023
-
Ingår i: ACS Photonics. - : American Chemical Society (ACS). - 2330-4022. ; 10:9, s. 3052-3059
-
Tidskriftsartikel (refereegranskat)abstract
- Free space optical communication (FSO) has gained significant attention due to the growing demand for a high information capacity. For FSO between multiple or moving targets, a receiver with a wide angle of acquisition capability is necessary. Traditionally, gimbals and fast steering mirrors have been used, but they are often difficult to make both compact and wide-angle. Here, a novel duplex FSO system is demonstrated, which utilizes a highly compact fiber coupling metalens to receive and transmit signals in a large field of view up to 80°. High coupling efficiency up to 48.8% at a wavelength of 1550 nm is experimentally achieved. The small coupling loss enables the user to modulate and direct the downstream power from the base station back along the same path, saving energy and leaving only one source in the FSO system. The low bit error rate and the open and clear eye diagram results validate the excellent downlink/uplink communication performance of a 10 Gbps FSO system empowered by the metalens. The system exhibits a large field of view, high data rate, compact size, and low power consumption, which meets the size, weight, and power requirement of smart devices.
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31. |
- Hu, Nan
(författare)
-
Climate change effects on marine species across trophic levels
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Climate change and anthropogenic activities are producing a range of new selection pressures, both abiotic and biotic, on marine organisms. While there are numerous studies that have investigated the response of individual marine organisms to climate change, few studies have focused on differences in organismal responses across trophic levels. Such trophic differences in response to climate change may disrupt ecological interactions and thereby threaten marine ecosystem function. In addition, predation is known as a strong driver that impacts individuals and populations. Despite this, we still do not have a comprehensive understanding of how different trophic levels respond to climate change stressors, predation and their combined effects in marine ecosystems.The main focus of this thesis is to identify whether marine trophic levels respond differently to climatic stressors and predation. To explore these questions, I have used a combination of traditional mesocosm experiments, together with a statistical method called meta-analysis. I initiated the research by study the responses of marine gastropods at two trophic levels to ocean acidification and predation using long-term mesocosm experiments together with a gastropod-specific meta-analyses. I focused on the amount of phenotypic plasticity in morphological traits of snails when exposed to the two stressors. In order to generalise and test these assumptions among a greater number of marine taxa, I used the meta-analysis approach to investigate the effects of ocean acidification and warming, as well as their combined effects on four marine trophic levels. Finally, to study the individual and combined effects of ocean acidification and predation with respect to inducible defences, I again applied a mesocosm experiment and used blue mussels as a model species. By using long-term mesocosm experiments and the gastropod-specific meta-analysis on marine gastropods from two trophic levels, I showed that these trophic levels varied in their responses to both ocean acidification and predation. Gastropods at lower trophic levels exhibited greater phenotypic plasticity against predation, while those from higher trophic levels showed stronger tolerance to ocean acidification. Next, by using a meta-analysis, including a large number of species and taxa, examining the effects of ocean acidification and warming, I revealed that top-predators and primary producers were most tolerant to ocean acidification compared to other trophic levels. Herbivores on the other hand, were the most vulnerable trophic level against abiotic stress. Again, using the meta-analysis approach, but this time incorporating only factorial experimental data that included the interactive effects of ocean acidification and ocean warming, I showed that higher trophic levels again were the most tolerant trophic level, and herbivores being most sensitive, with respect to the combined effect of the two stressors. Contrary to previous discussions in the literature concerning multiple climate-related stressors, antagonistic and additive effects occurred most frequently, while synergistic effects were less common and which decreased with increasing trophic rank. Finally, by conducting a fully-factorial experiment using blue mussels, I found that mussels with previous experience contact with predator has developed greater inducible defences than ones without previous experience. However, levels of ocean acidification may mask predator cues, or obstruct shell material, and consequently disrupt blue mussels inducible defence from crab predation. In summary, marine trophic levels respond differently to both biotic and climatic stressors. Higher trophic levels, together with primary producers, were often more robust against abiotic stress and may therefore be better prepared for future oceans compare species from lower trophic levels. These results may provide vital information for: implementing effective climate change mitigation, to understand which stressors to act on, and when and where to intervene for prioritizing conservation actions.
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32. |
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33. |
- Hu, Nan, et al.
(författare)
-
Elevated temperatures increase growth and enhance foraging performances of a marine gastropod
- 2021
-
Ingår i: Aquaculture Environment Interactions. - 1869-215X. ; 13, s. 177-188
-
Tidskriftsartikel (refereegranskat)abstract
- The oceans continue to warm due to rising atmospheric greenhouse gas concentrations. Most climate-change studies of aquaculture species use temperature changes based on coarse-resolution climate models and without considering thermal ranges of an animal. Coarse-resolution climate models are generated by global-scale data, which is insufficient to capture the conditions of coastal areas where most aquaculture activity occurs. Therefore, ocean warming research on coastal organisms requires a more comprehensive design to include broad temperature gradients. By using the ecologically and commercially important coastal whelk Rapana venosa, we combined long-term and short-term experiments and selected 4 temperature treatments (19, 23, 27, and 30°C) to simulate different scenarios to test ocean warming effects on growth rates and foraging performances of whelks. We found that elevated temperature within the whelk’s thermal range (23 and 27°C) significantly increased growth rates and enhanced foraging performances of marine whelks when compared to the current temperature (19°C). Conversely, the whelk’s performance collapsed at 30°C in terms of both growth and foraging behavior. Our research clearly shows that local conditions and the tolerance range of a species must be considered to develop meaningful information for testing the effects of a changing climate. Our study suggests that rapa whelks may increase their feeding and reach larger sizes during warmer periods. Moreover, our study may provide a foundation for future climate research on aquaculture species.
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34. |
- Hu, Nan, et al.
(författare)
-
Handling- or digestion-limited predators : the role of body mass and habitat complexity in predator functional response
- 2023
-
Ingår i: Marine Ecology Progress Series. - 0171-8630. ; 725, s. 1-14
-
Tidskriftsartikel (refereegranskat)abstract
- The predator functional response quantifies the per capita feeding rate of predators as a function of prey density and is a key element of feeding interactions. Variations in its parameters are strongly associated with interaction strength and population dynamics. We examined 18 functional responses within marine whelk−bivalve systems, varying predator body size, prey species, and habitat structure. Our findings suggest that the marine whelk Rapana venosa is handling-limited, a predator type that has received less attention in previous research. We propose further categorizing handling-limited predators into 2 types: pursuit-limited (where maximum feeding rate could be influenced by habitat complexity) and ingestion-limited (where maximum feeding rate is impacted not by habitat complexity, but by predator−prey body mass ratios and prey defense strategy). We found that handling time scales negatively with predator−prey body mass ratios, but this trend exhibits layers of complexity. We propose that the transition from handling to digestion limitation with increasing predator−prey body mass ratios underlies this trend. Our study also confirms the importance of prey types, in addition to known effects of body mass ratios and habitat structure. In summary, our study reveals that simple assumptions about body masses and prey defense strategy may usefully refine estimates of feeding interactions in complex food webs.
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35. |
- Hu, Nan, et al.
(författare)
-
Marine gastropods at higher trophic level show stronger tolerance to ocean acidification
- 2022
-
Ingår i: Oikos. - : Wiley. - 0030-1299 .- 1600-0706.
-
Tidskriftsartikel (refereegranskat)abstract
- Climate change and anthropogenic activities are producing a range of new selection pressures, both abiotic and biotic, on marine organisms. Although it is known that climate change can differentially affect fitness-related traits at different trophic levels of the food web, it is not clear if different trophic levels will respond via phenotypic plasticity in the form of maintenance of phenotypes in the face of abiotic and biotic environmental stress similarly. To answer this question, we combined a mesocosm experiment (120 days) using a food web comprising three gastropod species from two trophic levels (grazers and meso-predators) and a meta-analysis including 38 studies to address whether different trophic levels exhibit similar phenotypic responses to abiotic and biotic variables. Abiotic (ocean acidification) and biotic (predation) stress significantly influenced body mass, shell mass, shell thickness and shell strength in both grazers and meso-predators in the mesocosm experiment, with the magnitude of OA effects greater on the meso-predator than the grazers; a result supported by the meta-analysis. In contrast, both mesocosm experiment and meta-analysis found that predation risk induced stronger responses in shell morphology for grazers compared to meso-predators. Together, our findings indicate that higher trophic level species are better able to maintain aspects of their phenotype under OA, suggesting that they may show greater tolerance to climate change effects in general, while lower trophic levels express higher levels of plastic inducible defences to maintain function when under threat of predation. By using marine snails as a model, our study provides new knowledge for understanding how changing environmental conditions may alter biological interactions, and increases our understanding of how climate change may affect ecological communities in which gastropods play a key role.
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36. |
- Hu, Nan, et al.
(författare)
-
Meta-analysis reveals variance in tolerance to climate change across marine trophic levels
- 2022
-
Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697. ; 827
-
Forskningsöversikt (refereegranskat)abstract
- Marine ecosystems are currently facing a variety of anthropogenic perturbations, including climate change. Trophic differences in response to climate change may disrupt ecological interactions and thereby threaten marine ecosystem function. Yet, we still do not have a comprehensive understanding of how different trophic levels respond to climate change stressors in marine ecosystems. By including 1278 experiments, comprising 236 different marine species from 18 different phyla in a meta-analysis of studies measuring the direct effect of ocean acidification and ocean warming on marine organisms, we found that higher trophic level species display greater tolerance to ocean acidification but greater sensitivity to warming. In contrast, marine herbivores were the most vulnerable trophic level to both acidification and warming. Such imbalances in the community and a general reduction of biodiversity and biomass in lower trophic levels can significantly disrupt the system and could drive negative bottom-up effects. In conclusion, with ocean acidification and elevated temperatures, there is an alarming risk that trophic disparity may disrupt species interactions, and thereby drive community destabilization under ocean climate change.
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37. |
- Hu, Nan, et al.
(författare)
-
Responses of marine trophic levels to the combined effects of ocean acidification and warming
- 2024
-
Ingår i: Nature Communications. - 2041-1723. ; 15
-
Tidskriftsartikel (refereegranskat)abstract
- Marine organisms are simultaneously exposed to anthropogenic stressors associated with ocean acidification and ocean warming, with expected interactive effects. Species from different trophic levels with dissimilar characteristics and evolutionary histories are likely to respond differently. Here, we perform a meta-analysis of controlled experiments including both ocean acidification and ocean warming factors to investigate single and interactive effects of these stressors on marine species. Contrary to expectations, we find that synergistic interactions are less common (16%) than additive (40%) and antagonistic (44%) interactions overall and their proportion decreases with increasing trophic level. Predators are the most tolerant trophic level to both individual and combined effects. For interactive effects, calcifying and non-calcifying species show similar patterns. We also identify climate region-specific patterns, with interactive effects ranging from synergistic in temperate regions to compensatory in subtropical regions, to positive in tropical regions. Our findings improve understanding of how ocean warming, and acidification affect marine trophic levels and highlight the need for deeper consideration of multiple stressors in conservation efforts.
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38. |
- Hu, Nan, et al.
(författare)
-
Review of experimental measurements on particle size distribution and airflow behaviors during human respiration
- 2024
-
Ingår i: Building and Environment. - : Elsevier. - 0360-1323 .- 1873-684X. ; 247
-
Tidskriftsartikel (refereegranskat)abstract
- In recent years, pandemic outbreaks have raised concerns about the spread of respiratory infections and their impact on public health. Since the pathogen emission during human respiration is recognized as the primary source, characterizing the physical properties of exhaled particles and airflow has become a crucial focus of attention. This article critically reviews experimental studies in exhaled particles and airflow, examines the uncertainty introduced by different measurement methods, analyzes how it is reflected in measurement outcomes, and provides an in-depth understanding of particle size distribution and airflow behaviors of human respiration. The measurement techniques assessment highlights the variability among particle sizing techniques in detection size range, collection efficiency, hydration status of captured particles, and experimental protocols. A combination of sampling-based instruments and laser imaging systems is recommended for particle sizing to cover a wider detection range, with refined setups in thermal conditions, sampling distance, volume, and duration. Meanwhile, it identifies the complementary nature of qualitative and quantitative measurements of airflow characterization techniques. Image recording systems plus data reconstruction programs are suggested to capture dynamic airflow features while accuracy validation by other techniques is required at the same time. Subsequent analysis of the measurement data showed that the various experimental measurements provided substantial information, but they also revealed disagreements and challenges in quantification. The dominance of submicron aerosols in exhaled particles and jet-like transport in exhaled airflow is obvious. More efforts should be made to measure particles larger than 20 μm, capture airflow dynamics in a high temporal and spatial resolution, and quantify the impact of face coverings to improve the understanding of human respiratory emissions.
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39. |
- Hu, Nan, et al.
(författare)
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Ventilation performance evaluation of an operating room with temperature-controlled airflow system in contaminant control : A numerical study
- 2024
-
Ingår i: Building and Environment. - : Elsevier Ltd. - 0360-1323 .- 1873-684X. ; 259
-
Tidskriftsartikel (refereegranskat)abstract
- This article investigates the efficacy of temperature-controlled airflow systems in modern operating rooms for contaminant control, a critical factor in preventing surgical site infections. We have conducted experimental measurements in an operating room equipped with temperature-controlled ventilation to map the airflow field and contaminant dispersion (airborne particles with diameters ranging from 0.5 to 1 μm). The results were used to validate the computational fluid dynamics code, which was then employed to simulate and examine different conditions, including contaminant release locations and air supply rates. Realizable k-epsilon and passive scalar models were utilized to simulate airflow and airborne particle phases. We assessed the airflow distribution and contaminant dispersion, utilizing indices such as ventilation and air change efficiency scales. The analysis provided quantitative insights into the distribution and removal of contaminants, as well as the speed at which the room air was replaced. Contamination was found to be effectively reduced when contaminants were released near exhaust outlets or under central unidirectional inlets. The presence of the operating table caused a big distortion of the central downward airflow, forming a horizontal air barrier at the periphery. Under this unique interior configuration, an appropriate air supply ratio between central and periphery zones was required to achieve optimal overall ventilation performance.
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40. |
- Hu, Zhang Nan, et al.
(författare)
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Hausdorff dimension of recurrence sets
- 2024
-
Ingår i: Nonlinearity. - 0951-7715. ; 37:5
-
Tidskriftsartikel (refereegranskat)abstract
- We consider linear mappings on the 2-dimensional torus, defined by T ( x ) = A x ( mod 1 ) , where A is an invertible 2 × 2 integer matrix, with no eigenvalues on the unit circle. In the case det A = ± 1 , we give a formula for the Hausdorff dimension of the set { x ∈ T 2 : d ( T n ( x ) , x ) < e − α n for infinitely many n } .
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41. |
- Hu, Zhipeng, et al.
(författare)
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Wideband High-Reflection Chiral Dielectric Metasurface
- 2021
-
Ingår i: Progress In Electromagnetics Research. - : EMW PUBLISHING. - 1070-4698 .- 1559-8985. ; 172, s. 51-60
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Tidskriftsartikel (refereegranskat)abstract
- Compared to natural materials, artificial subwavelength structures can enhance chiroptical effects in a stronger way, and the requirement of low material loss and wideband operation is desired in many situations. Here, we propose an all-dielectric chiral metasurface as a periodic array of centrosymmetric staggered silicon cuboid pairs to achieve strong circular dichroism in a wide band. As a demonstration, the designed chiral metasurface may strongly reflect the chosen circularly polarized light with the spin preserved in the operating wavelength range of 1.51 ti 1.60 mu m while highly transmit (with an efficiency greater than 95%) the opposite circularly polarized light with the spin flipped. Then, two application cases are given for the designed chiral metasurface. A flat chiral meta-lens is constructed to produce wideband focusing in the transmission/reflection side while the disturbing from the opposite circular polarization is well blocked by high reflection/transmission. A chiral Fabry-Perot cavity is also constructed, which has an extremely high quality factor (2.1E4). The proposed method provides an efficient way to produce strong chiroptical effects and has a promising potential for various applications such as signal processing, sensing, radiation and detection.
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42. |
- Huang, Yajun, et al.
(författare)
-
Experimental study of flame spread over thermally-thin inclined fuel surface and controlling heat transfer mechanism under concurrent wind
- 2021
-
Ingår i: International Journal of Thermal Sciences. - : Elsevier BV. - 1290-0729. ; 165
-
Tidskriftsartikel (refereegranskat)abstract
- The fuel inclination and wind velocity play a significant role on the forward flame spread behavior. It deserves further study since the heat transfer mechanism and flame spread characteristics coupled these two factors are not clear yet. In this paper, a thermally thin slab of PMMA that could be inclined from a horizontal (0°) to a vertical (90°) angle is used to investigate flame spread behavior under the condition of the concurrent ambient airflow. A wind tunnel is utilized to provide a uniform concurrent airflow, ranging from 0 (quiescent) to 3 m/s with an interval of 0.5 m/s. Essential flame characteristic parameters are collected to quantify the flame spread process, including flame spread rate (FSR), burning rate, heat release rate as well as heat flux feedback both in the pyrolysis and preheating zones. A mechanism, including the competition between the acceleration of buoyancy brought by inclination and the cooling effect of ambient airflow for relatively high wind velocity, is developed. The relationship between flame length and pyrolysis length is investigated. Moreover, the evolution of both heat release rate per unit width and standoff distance as a function of pyrolysis length are analyzed. A dimensionless heat release rate for upward flame at different wind velocities is used to scale the dimensionless flame length with a power-law exponent of 0.77 and −1.92. In addition, the dimensionless heat flux in preheated zone decay with distance as a function of power law. A predictive formulation of FSR coupled with inclination angle and wind velocity is proposed. This study facilitates the understanding of the interaction of fuel inclination angle and horizontal ambient airflow from aspect of heat and mass transfer.
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43. |
- Lee, Marcus, et al.
(författare)
-
Low-latitude zooplankton pigmentation plasticity in response to multiple threats
- 2019
-
Ingår i: Royal Society Open Science. - : Royal Society Open Science. - 2054-5703. ; 6:7, s. 1-10
-
Tidskriftsartikel (refereegranskat)abstract
- Crustacean copepods in high-latitude lakes frequently alter their pigmentation facultatively to defend themselves against prevailing threats, such as solar ultraviolet radiation ( UVR) and visually oriented predators. Strong seasonality in those environments promotes phenotypic plasticity. To date, no one has investigated whether low-latitude copepods, experiencing continuous stress from UVR and predation threats, exhibit similar inducible defences. We here investigated the pigmentation levels of Bahamian 'blue hole' copepods, addressing this deficit. Examining several populations varying in predation risk, we found the lowest levels of pigmentation in the population experiencing the highest predation pressure. In a laboratory experiment, we found that, in contrast with our predictions, copepods from these relatively constant environments did show some changes in pigmentation subsequent to the removal of UVR; however, exposure to water from different predation regimes induced minor and idiosyncratic pigmentation change. Our findings suggest that low-latitude zooplankton in inland environments may exhibit reduced, but non-zero, levels of phenotypic plasticity compared with their high-latitude counterparts.
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44. |
- Li, Junhao, et al.
(författare)
-
Full-color enhanced second harmonic generation using rainbow trapping in ultrathin hyperbolic metamaterials
- 2021
-
Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 12:1
-
Tidskriftsartikel (refereegranskat)abstract
- Though metamaterials enhance nonlinear light-matter interactions due to their resonant features, these materials typically show a narrow spectral bandwidth. Here, the authors report broadband enhanced second-harmonic generation in patterned multilayer hyperbolic metamaterial arrays. Metasurfaces have provided a promising approach to enhance the nonlinearity at subwavelength scale, but usually suffer from a narrow bandwidth as imposed by sharp resonant features. Here, we counterintuitively report a broadband, enhanced second-harmonic generation, in nanopatterned hyperbolic metamaterials. The nanopatterning allows the direct access of the mode with large momentum, rendering the rainbow light trapping, i.e. slow light in a broad frequency, and thus enhancing the local field intensity for boosted nonlinear light-matter interactions. For a proof-of-concept demonstration, we fabricated a nanostructured Au/ZnO multilayer, and enhanced second harmonic generation can be observed within the visible wavelength range (400-650 nm). The enhancement factor is over 50 within the wavelength range of 470-650 nm, and a maximum conversion efficiency of 1.13x10(-6) is obtained with a pump power of only 8.80 mW. Our results herein offer an effective and robust approach towards the broadband metasurface-based nonlinear devices for various important technologies.
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45. |
- Li, Nan, et al.
(författare)
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On Resource Allocation of Cooperative Multiple Access Strategy in Energy-Efficient Industrial Internet of Things
- 2021
-
Ingår i: IEEE Transactions on Industrial Informatics. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 1551-3203 .- 1941-0050. ; 17:2, s. 1069-1078
-
Tidskriftsartikel (refereegranskat)abstract
- An event-triggered attitude control algorithm is developed for quadrotor unmanned aerial vehicles (UAVs) subject to external disturbances. In this article, first an event-triggered supertwisting stabilizing control strategy for a class of second-order nonlinear systems is proposed. Then, a Lyapunov-based stability analysis is provided for the closed-loop system, and the Zeno-free execution of triggering sequence is guaranteed via rigorous analysis. Furthermore, the proposed control strategy is applied on attitude control of UAVs to reduce the computing cost without degrading the performance of the system. Finally, the efficiency of the developed method is validated by numerical simulation.
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46. |
- Lubong Sabado, Rachel, et al.
(författare)
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Evidence of dysregulation of dendritic cells in primary HIV infection
- 2010
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Ingår i: BLOOD. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 116:19, s. 3839-3852
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Tidskriftsartikel (refereegranskat)abstract
- Myeloid and plasmacytoid dendritic cells (DCs) are important mediators of both innate and adaptive immunity against pathogens such as HIV. During the course of HIV infection, blood DC numbers fall substantially. In the present study, we sought to determine how early in HIV infection the reduction occurs and whether the remaining DC subsets maintain functional capacity. We find that both myeloid DC and plasmacytoid DC levels decline very early during acute HIV infection. Despite the initial reduction in numbers, those DCs that remain in circulation retain their function and are able to stimulate allogeneic T-cell responses, and up-regulate maturation markers plus produce cytokines/chemokines in response to stimulation with TLR7/8 agonists. Notably, DCs from HIV-infected subjects produced significantly higher levels of cytokines/chemokines in response to stimulation with TLR7/8 agonists than DCs from uninfected controls. Further examination of gene expression profiles indicated in vivo activation, either directly or indirectly, of DCs during HIV infection. Taken together, our data demonstrate that despite the reduction in circulating DC numbers, those that remain in the blood display hyperfunctionality and implicates a possible role for DCs in promoting chronic immune activation.
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47. |
- Luo, Yifei, et al.
(författare)
-
Technology Roadmap for Flexible Sensors
- 2023
-
Ingår i: ACS Nano. - : American Chemical Society. - 1936-0851 .- 1936-086X. ; 17:6, s. 5211-5295
-
Forskningsöversikt (refereegranskat)abstract
- Humans rely increasingly on sensors to address grand challenges and to improve quality of life in the era of digitalization and big data. For ubiquitous sensing, flexible sensors are developed to overcome the limitations of conventional rigid counterparts. Despite rapid advancement in bench-side research over the last decade, the market adoption of flexible sensors remains limited. To ease and to expedite their deployment, here, we identify bottlenecks hindering the maturation of flexible sensors and propose promising solutions. We first analyze challenges in achieving satisfactory sensing performance for real-world applications and then summarize issues in compatible sensor-biology interfaces, followed by brief discussions on powering and connecting sensor networks. Issues en route to commercialization and for sustainable growth of the sector are also analyzed, highlighting environmental concerns and emphasizing nontechnical issues such as business, regulatory, and ethical considerations. Additionally, we look at future intelligent flexible sensors. In proposing a comprehensive roadmap, we hope to steer research efforts towards common goals and to guide coordinated development strategies from disparate communities. Through such collaborative efforts, scientific breakthroughs can be made sooner and capitalized for the betterment of humanity.
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48. |
- Meng, Fandong, et al.
(författare)
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Consistent time allocation fraction to vegetation green-up versus senescence across northern ecosystems despite recent climate change
- 2024
-
Ingår i: Science Advances. - 2375-2548. ; 10:23
-
Tidskriftsartikel (refereegranskat)abstract
- Extended growing season lengths under climatic warming suggest increased time for plant growth. However, research has focused on climatic impacts to the timing or duration of distinct phenological events. Comparatively little is known about impacts to the relative time allocation to distinct phenological events, for example, the proportion of time dedicated to leaf growth versus senescence. We use multiple satellite and ground-based observations to show that, despite recent climate change during 2001 to 2020, the ratio of time allocated to vegetation green-up over senescence has remained stable [1.27 (± 0.92)] across more than 83% of northern ecosystems. This stability is independent of changes in growing season lengths and is caused by widespread positive relationships among vegetation phenological events; longer vegetation green-up results in longer vegetation senescence. These empirical observations were also partly reproduced by 13 dynamic global vegetation models. Our work demonstrates an intrinsic biotic control to vegetation phenology that could explain the timing of vegetation senescence under climate change.
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49. |
- Nan, Jun-hu, et al.
(författare)
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Air-core characteristics in a swirling tunnel flow
- 2022
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Ingår i: Journal of Hydrodynamics. - : Springer Nature. - 1001-6058 .- 1000-4874 .- 1878-0342. ; 34:4, s. 634-646
-
Tidskriftsartikel (refereegranskat)abstract
- A cost-effective technique to dissipate the energy in hydropower systems is the formation of a swirling flow within a tunnel. In such flows, an air core with a significant cross section usually occurs. To reveal the air-core features in the horizontal tunnel of a high-head shaft spillway, laboratory tests, numerical modeling, and prototype observations are performed, to examine issues such as the formation of the air core, the interjacent air motion, the air-carrying capacity, and the scale effects. It is shown that the shape of the air core varies greatly in the axial and radial directions along the tunnel and that the center of the core deviates from the axis of the tunnel. The motion of the air within the core is caused by the combined action of the water entrainment on the inner surface of the swirling flow and the axial pressure difference in the air core. The aeration process can be divided into five processes with respect to the changes of the gate openings. A theoretical expression is established for the air-carrying capacity of the swirling flow. The vacuum degree is the similarity condition of the air-carrying capacity of the swirling flow between the model and prototype tests based on the Froude law of the similitude, and this similarity condition is verified by both the model and prototype results. This work provides a reference for the application of the swirling flows in horizontal hydropower tunnels.
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50. |
- Pärssinen, Varpu, et al.
(författare)
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Variation in predation regime drives sex-specific differences in mosquitofish foraging behaviour
- 2021
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Ingår i: Oikos. - : Wiley-Blackwell. - 0030-1299 .- 1600-0706. ; 130:5, s. 790-797
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Tidskriftsartikel (refereegranskat)abstract
- Predation is a well-studied driver of ecological selection on prey traits, which frequently drives divergence in anti-predator performance across environments that vary in predation risk. However, predation also alters prey mortality regimes, where low predation risk often results in higher prey densities and consequently higher intensities of intraspecific resource competition. In addition, predation risk alters the foraging context, as acquiring food can be risky in the presence of predators. Thus, different predation regimes can drive divergent selection on traits associated with resource competition, such as foraging behaviours. Moreover, because sexes often differ in susceptibility to predation and limitations to their reproductive output, the intensity of the tradeoff between predator avoidance and resource competition may depend on sex. We used a laboratory experiment to assess key aspects of foraging performance in a predator-free context in Bahamas mosquitofish Gambusia hubbsi wild-caught from multiple populations that experience either high or low levels of predation risk. When competing for limited food resources at a common density, females from low-predation regimes showed higher foraging and food consumption rates than females from high-predation regimes. Males showed fewer differences between predation regimes, and an opposite pattern from females. We suggest these sex-specific effects result from females facing a greater tradeoff between predation risk and resource competition, combined with males from high-predation environments elevating foraging behaviours in the absence of nearby predators and females. Females of this species are larger than males, bear live young and show higher foraging rates in the wild than males. On the other hand, males spend more time pursuing females in the wild, and may exhibit greater flexibility in foraging behaviours based on the immediate context. Our results show that varying levels of predation risk can lead to differences in behaviours associated with resource competition, but these effects can strongly differ between sexes.
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