| 1. |
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| 2. |
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- 2019
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Tidskriftsartikel (refereegranskat)
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| 3. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 4. |
- Klionsky, Daniel J., et al.
(författare)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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Forskningsöversikt (refereegranskat)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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| 5. |
- Schael, S, et al.
(författare)
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Precision electroweak measurements on the Z resonance
- 2006
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Ingår i: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 427:5-6, s. 257-454
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Forskningsöversikt (refereegranskat)abstract
- We report on the final electroweak measurements performed with data taken at the Z resonance by the experiments operating at the electron-positron colliders SLC and LEP. The data consist of 17 million Z decays accumulated by the ALEPH, DELPHI, L3 and OPAL experiments at LEP, and 600 thousand Z decays by the SLID experiment using a polarised beam at SLC. The measurements include cross-sections, forward-backward asymmetries and polarised asymmetries. The mass and width of the Z boson, m(Z) and Gamma(Z), and its couplings to fermions, for example the p parameter and the effective electroweak mixing angle for leptons, are precisely measured: m(Z) = 91.1875 +/- 0.0021 GeV, Gamma(Z) = 2.4952 +/- 0.0023 GeV, rho(l) = 1.0050 +/- 0.0010, sin(2)theta(eff)(lept) = 0.23153 +/- 0.00016. The number of light neutrino species is determined to be 2.9840 +/- 0.0082, in agreement with the three observed generations of fundamental fermions. The results are compared to the predictions of the Standard Model (SM). At the Z-pole, electroweak radiative corrections beyond the running of the QED and QCD coupling constants are observed with a significance of five standard deviations, and in agreement with the Standard Model. Of the many Z-pole measurements, the forward-backward asymmetry in b-quark production shows the largest difference with respect to its SM expectation, at the level of 2.8 standard deviations. Through radiative corrections evaluated in the framework of the Standard Model, the Z-pole data are also used to predict the mass of the top quark, m(t) = 173(+10)(+13) GeV, and the mass of the W boson, m(W) = 80.363 +/- 0.032 GeV. These indirect constraints are compared to the direct measurements, providing a stringent test of the SM. Using in addition the direct measurements of m(t) and m(W), the mass of the as yet unobserved SM Higgs boson is predicted with a relative uncertainty of about 50% and found to be less than 285 GeV at 95% confidence level. (c) 2006 Elsevier B.V. All rights reserved.
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| 6. |
- Schael, S., et al.
(författare)
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Electroweak measurements in electron positron collisions at W-boson-pair energies at LEP
- 2013
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Ingår i: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 532:4, s. 119-244
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Forskningsöversikt (refereegranskat)abstract
- Electroweak measurements performed with data taken at the electron positron collider LEP at CERN from 1995 to 2000 are reported. The combined data set considered in this report corresponds to a total luminosity of about 3 fb(-1) collected by the four LEP experiments ALEPH, DELPHI, 13 and OPAL, at centre-of-mass energies ranging from 130 GeV to 209 GeV. Combining the published results of the four LEP experiments, the measurements include total and differential cross-sections in photon-pair, fermion-pair and four-fermion production, the latter resulting from both double-resonant WW and ZZ production as well as singly resonant production. Total and differential cross-sections are measured precisely, providing a stringent test of the Standard Model at centre-of-mass energies never explored before in electron positron collisions. Final-state interaction effects in four-fermion production, such as those arising from colour reconnection and Bose Einstein correlations between the two W decay systems arising in WW production, are searched for and upper limits on the strength of possible effects are obtained. The data are used to determine fundamental properties of the W boson and the electroweak theory. Among others, the mass and width of the W boson, m(w) and Gamma(w), the branching fraction of W decays to hadrons, B(W -> had), and the trilinear gauge-boson self-couplings g(1)(Z), K-gamma and lambda(gamma), are determined to be: m(w) = 80.376 +/- 0.033 GeV Gamma(w) = 2.195 +/- 0.083 GeV B(W -> had) = 67.41 +/- 0.27% g(1)(Z) = 0.984(-0.020)(+0.018) K-gamma - 0.982 +/- 0.042 lambda(gamma) = 0.022 +/- 0.019. (C) 2013 Elsevier B.V. All rights reserved.
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| 7. |
- Kristanl, Matej, et al.
(författare)
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The Seventh Visual Object Tracking VOT2019 Challenge Results
- 2019
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Ingår i: 2019 IEEE/CVF INTERNATIONAL CONFERENCE ON COMPUTER VISION WORKSHOPS (ICCVW). - : IEEE COMPUTER SOC. - 9781728150239 ; , s. 2206-2241
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Konferensbidrag (refereegranskat)abstract
- The Visual Object Tracking challenge VOT2019 is the seventh annual tracker benchmarking activity organized by the VOT initiative. Results of 81 trackers are presented; many are state-of-the-art trackers published at major computer vision conferences or in journals in the recent years. The evaluation included the standard VOT and other popular methodologies for short-term tracking analysis as well as the standard VOT methodology for long-term tracking analysis. The VOT2019 challenge was composed of five challenges focusing on different tracking domains: (i) VOT-ST2019 challenge focused on short-term tracking in RGB, (ii) VOT-RT2019 challenge focused on "real-time" short-term tracking in RGB, (iii) VOT-LT2019 focused on long-term tracking namely coping with target disappearance and reappearance. Two new challenges have been introduced: (iv) VOT-RGBT2019 challenge focused on short-term tracking in RGB and thermal imagery and (v) VOT-RGBD2019 challenge focused on long-term tracking in RGB and depth imagery. The VOT-ST2019, VOT-RT2019 and VOT-LT2019 datasets were refreshed while new datasets were introduced for VOT-RGBT2019 and VOT-RGBD2019. The VOT toolkit has been updated to support both standard short-term, long-term tracking and tracking with multi-channel imagery. Performance of the tested trackers typically by far exceeds standard baselines. The source code for most of the trackers is publicly available from the VOT page. The dataset, the evaluation kit and the results are publicly available at the challenge website(1).
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| 8. |
- Sun, Hui-Min, et al.
(författare)
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SERPINA4 is a novel independent prognostic indicator and a potential therapeutic target for colorectal cancer
- 2016
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Ingår i: American Journal of Cancer Research. - Madison : E-CENTURY PUBLISHING CORP. - 2156-6976. ; 6:8, s. 1636-1649
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Tidskriftsartikel (refereegranskat)abstract
- Serpina family A member 4 (SERPINA4), also known as kallistatin, exerts important effects in inhibiting tumor growth and angiogenesis in many malignancies. However, the precise role of SERPINA4 in CRC has not been fully elucidated. The present study aimed to investigate the expression of SERPINA4 and its clinical significance in CRC. Quantitative real-time polymerase chain reaction (qRT-PCR) and western blot analyses showed that the mRNA and protein expression of SERPINA4 in colorectal cancer (CRC) specimens was significantly decreased than that in adjacent normal mucosa. Immunohistochemistry (IHC) was conducted to characterize the expression pattern of SERPINA4 by using a tissue microarray (TMA) containing 327 archived paraffin-embedded CRC specimens. Statistical analyses revealed that decreased SERPINA4 expression was significantly associated with invasion depth, nodal involvement, distant metastasis, American Joint Committee on Cancer (AJCC) stage, and tumor differentiation. SERPINA4 was also an independent prognostic indicator of disease-free survival and overall survival in patients with CRC. Furthermore, the impact of altered SERPINA4 expression on CRC cells was analyzed with a series of in vitro and in vivo assays. The results demonstrated that SERPINA4 significantly inhibits malignant tumor progression and serves as a novel prognostic indicator and a potential therapeutic target for CRC.
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| 9. |
- Wang, Guo-Dong, et al.
(författare)
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Out of southern East Asia : the natural history of domestic dogs across the world
- 2016
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Ingår i: Cell Research. - : Nature Publishing Group. - 1001-0602 .- 1748-7838. ; 26:1, s. 21-33
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Tidskriftsartikel (refereegranskat)abstract
- The origin and evolution of the domestic dog remains a controversial question for the scientific community, with basic aspects such as the place and date of origin, and the number of times dogs were domesticated, open to dispute. Using whole genome sequences from a total of 58 canids (12 gray wolves, 27 primitive dogs from Asia and Africa, and a collection of 19 diverse breeds from across the world), we find that dogs from southern East Asia have significantly higher genetic diversity compared to other populations, and are the most basal group relating to gray wolves, indicating an ancient origin of domestic dogs in southern East Asia 33 000 years ago. Around 15 000 years ago, a subset of ancestral dogs started migrating to the Middle East, Africa and Europe, arriving in Europe at about 10 000 years ago. One of the out of Asia lineages also migrated back to the east, creating a series of admixed populations with the endemic Asian lineages in northern China before migrating to the New World. For the first time, our study unravels an extraordinary journey that the domestic dog has traveled on earth.
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| 10. |
- Zhang, Shao-jie, et al.
(författare)
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Genomic regions under selection in the feralization of the dingoes
- 2020
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Ingår i: Nature Communications. - : NATURE PUBLISHING GROUP. - 2041-1723. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Dingoes are wild canids living in Australia, originating from domestic dogs. They have lived isolated from both the wild and the domestic ancestor, making them a unique model for studying feralization. Here, we sequence the genomes of 10 dingoes and 2 New Guinea Singing Dogs. Phylogenetic and demographic analyses show that dingoes originate from dogs in southern East Asia, which migrated via Island Southeast Asia to reach Australia around 8300 years ago, and subsequently diverged into a genetically distinct population. Selection analysis identifies 50 positively selected genes enriched in digestion and metabolism, indicating a diet change during feralization of dingoes. Thirteen of these genes have shifted allele frequencies compared to dogs but not compared to wolves. Functional assays show that an A-to-G mutation in ARHGEF7 decreases the endogenous expression, suggesting behavioral adaptations related to the transitions in environment. Our results indicate that the feralization of the dingo induced positive selection on genomic regions correlated to neurodevelopment, metabolism and reproduction, in adaptation to a wild environment.
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| 11. |
- Zhang, Ting, et al.
(författare)
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Microstructure evolution and deformation mechanism of alpha plus beta dual-phase Ti-xNb-yTa-2Zr alloys with high performance
- 2022
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Ingår i: Journal of Materials Science & Technology. - : Elsevier BV. - 1005-0302. ; 131, s. 68-81
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Tidskriftsartikel (refereegranskat)abstract
- Biomedical beta-phase Ti-Nb-Ta-Zr alloys usually exhibit low elastic modulus with inadequate strength. In the present work, a series of newly developed dual-phase Ti-xNb-yTa-2Zr (wt.%) alloys with high performance were investigated in which the stability of beta-phase was reduced under the guidelines of ab initio calculations and d-electronic theory. The effects of Nb and Ta contents on the microstructure, compressive and tensile properties were investigated. Results demonstrate that the designed Ti-xNb-yTa-2Zr alloys exhibit typical characteristics of alpha+beta dual-phase microstructure. The microstructure of the alloys is more sensitive to Nb rather than Ta. The as-cast alloys exhibit needle-like alpha' martensite at a lower Nb content of 3 wt.% and lamellar alpha' martensite at an Nb content of 5 wt.%. Among the alloys, the Ti-3Nb-13Ta-2Zr alloy shows the highest compressive strength (2270 +/- 10 MPa) and compressive strain (74.3% +/- 0.4%). This superior performance is due to the combination of alpha+beta dual-phase microstructure and stress-induced alpha '' martensite. Besides, lattice distortion caused by Ta element also contributes to the compressive properties. Nb and Ta contents of the alloys strongly affect Young's modulus and tensile properties after rolling. The as-rolled Ti-3Nb-13Ta-2Zr alloy exhibits much lower modulus due to lower Nb content as well as more alpha '' martensite and beta phase with a good combination of low modulus and high strength among all the designed alloys. Atom probe tomography analysis reveals the element partitioning between the a and beta phases in which Ta concentration is higher than Nb in the alpha phase. Also, the concentration of Ta is lower than that of Nb in the beta phase, indicating that the beta-stability of Nb is higher than that of Ta. This work proposes modern alpha+beta dual-phase Ti-xNb-yTa-2Zr alloys as a new concept to design novel biomedical Ti alloys with high performance.
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| 12. |
- Niemi, MEK, et al.
(författare)
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- 2021
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swepub:Mat__t
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| 13. |
- Kanai, M, et al.
(författare)
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- 2023
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swepub:Mat__t
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| 14. |
- Chen, Jialin, et al.
(författare)
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Fos Promotes Early Stage Teno-Lineage Differentiation of Tendon Stem/Progenitor Cells in Tendon
- 2017
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Ingår i: Stem Cells Translational Medicine. - : John Wiley & Sons. - 2157-6564 .- 2157-6580. ; 6:11, s. 2009-2019
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Tidskriftsartikel (refereegranskat)abstract
- Stem cells have been widely used in tendon tissue engineering. The lack of refined and controlled differentiation strategy hampers the tendon repair and regeneration. This study aimed to find new effective differentiation factors for stepwise tenogenic differentiation. By microarray screening, the transcript factor Fos was found to be expressed in significantly higher amounts in postnatal Achilles tendon tissue derived from 1 day as compared with 7-days-old rats. It was further confirmed that expression of Fos decreased with time in postnatal rat Achilles tendon, which was accompanied with the decreased expression of multiply tendon markers. The expression of Fos also declined during regular in vitro cell culture, which corresponded to the loss of tendon phenotype. In a cell-sheet and a three-dimensional cell culture model, the expression of Fos was upregulated as compared with in regular cell culture, together with the recovery of tendon phenotype. In addition, significant higher expression of tendon markers was found in Fos-overexpressed tendon stem/progenitor cells (TSPCs), and Fos knock-down gave opposite results. In situ rat tendon repair experiments found more normal tendon-like tissue formed and higher tendon markers expression at 4 weeks postimplantation of Fos-overexpressed TSPCs derived nonscaffold engineering tendon (cell-sheet), as compared with the control group. This study identifies Fos as a new marker and functional driver in the early stage teno-lineage differentiation of tendon, which paves the way for effective stepwise tendon differentiation and future tendon regeneration.
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| 15. |
- Chen, Wei-Ting, et al.
(författare)
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Spatial Transcriptomics and In Situ Sequencing to Study Alzheimer's Disease
- 2020
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Ingår i: Cell. - : Elsevier BV. - 0092-8674 .- 1097-4172. ; 182:4, s. 976-
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Tidskriftsartikel (refereegranskat)abstract
- Although complex inflammatory-like alterations are observed around the amyloid plaques of Alzheimer's disease (AD), little is known about the molecular changes and cellular interactions that characterize this response, We investigate here, in an AD mouse model, the transcriptional changes occurring in tissue domains in a 100-mu m diameter around amyloid plaques using spatial transcriptomics. We demonstrate early alterations in a gene co-expression network enriched for myelin and oligodendrocyte genes (OLIGs), whereas a multicellular gene co-expression network of plaque-induced genes (PIGs) involving the complement system, oxidative stress, lysosomes, and inflammation is prominent in the later phase of the disease. We confirm the majority of the observed alterations at the cellular level using in situ sequencing on mouse and human brain sections. Genome-wide spatial transcriptomics analysis provides an unprecedented approach to untangle the dysregulated cellular network in the vicinity of pathogenic hallmarks of AD and other brain diseases.
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| 16. |
- Chen, Yao, et al.
(författare)
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Thyroid hormone enhances nitric oxide mediated bacterial clearance and promotes survival after meningococcal infection
- 2012
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:7
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Tidskriftsartikel (refereegranskat)abstract
- Euthyroid sick syndrome characterized by reduced levels of thyroid hormones (THs) is observed in patients with meningococcal shock. It has been found that the level of THs reflects disease severity and is predictive for mortality. The present study was conducted to investigate the impact of THs on host defense during meningococcal infection. We found that supplementation of thyroxine to mice infected with Neisseria meningitidis enhanced bacterial clearance, attenuated the inflammatory responses and promoted survival. In vitro studies with macrophages revealed that THs enhanced bacteria-cell interaction and intracellular killing of meningococci by stimulating inducible nitric oxide synthase (iNos)-mediated NO production. TH treatment did not activate expression of TH receptors in macrophages. Instead, the observed TH-directed actions were mediated through nongenomic pathways involving the protein kinases PI3K and ERK1/2 and initiated at the membrane receptor integrin alpha v beta 3. Inhibition of nongenomic TH signaling prevented iNos induction, NO production and subsequent intracellular bacterial killing by macrophages. These data demonstrate a beneficial role of THs in macrophage-mediated N. meningitidis clearance. TH replacement might be a novel option to control meningococcal septicemia.
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| 17. |
- Chen, Yujie, et al.
(författare)
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Unraveling dual phase transformations in a CrCoNi medium-entropy alloy
- 2021
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Ingår i: Acta Materialia. - : Elsevier BV. - 1359-6454 .- 1873-2453. ; 215
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Tidskriftsartikel (refereegranskat)abstract
- The emergence of multi-principal element alloys (MPEAs) holds great promise for the development of high performance metallic materials. However, it remains unclear whether MPEAs can provide previously unknown deformation mechanisms to drastically enhance their mechanical performance. Here we report a new deformation mechanism of mechanically-induced dual phase transformations from the face-centered cubic (FCC) to hexagonal close- packed (HCP) phase and then back to the FCC phase with nanotwins in a CrCoNi medium-entropy alloy (MEA). During the two sequential steps of phase transformation, continued shear occurs in the same < 110 >(FCC) parallel to < 11 (2) over bar0 >(HCP) direction along different {111}(FCC) parallel to (0001)(HCP) planes, producing a total shear transformation strain up to 70%. The dual phase transformations stem from a unique capability of facile slip in between the close-packed {111}(FCC) parallel to (0001)(HCP) atomic layers in both FCC and HCP phases, leading to flexible stacking sequences of those close-packed layers with low stacking fault energies. Our work demonstrates that MPEAs can offer unconventional deformation mechanisms such as dual phase transformations in the CrCoNi MEA, thereby opening opportunities for enhancing the mechanical properties of advanced alloys.
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| 18. |
- Cheng, Yu Ting, et al.
(författare)
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Tuning atom-field interaction via phase shaping
- 2024
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Ingår i: Physical Review A. - 2469-9934 .- 2469-9926. ; 109:2
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Tidskriftsartikel (refereegranskat)abstract
- A coherent electromagnetic field can be described by its amplitude, frequency, and phase. All these properties can influence the interaction between the field and an atom. Here we demonstrate the phase shaping of microwaves that are scattered by a superconducting artificial atom coupled to the end of a semi-infinite one-dimensional transmission line. In particular, we input a weak exponentially rising pulse with phase modulation to a transmon qubit. We observe that atom-field interaction can be tuned from a nearly full interaction (interaction efficiency, i.e., amount of the field energy interacting with the atom, of 94.5 %) to effectively no interaction (interaction efficiency of 3.5 %).
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| 19. |
- Cho, Yoon Shin, et al.
(författare)
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Meta-analysis of genome-wide association studies identifies eight new loci for type 2 diabetes in east Asians.
- 2012
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 44:1
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Tidskriftsartikel (refereegranskat)abstract
- We conducted a three-stage genetic study to identify susceptibility loci for type 2 diabetes (T2D) in east Asian populations. We followed our stage 1 meta-analysis of eight T2D genome-wide association studies (6,952 cases with T2D and 11,865 controls) with a stage 2 in silico replication analysis (5,843 cases and 4,574 controls) and a stage 3 de novo replication analysis (12,284 cases and 13,172 controls). The combined analysis identified eight new T2D loci reaching genome-wide significance, which mapped in or near GLIS3, PEPD, FITM2-R3HDML-HNF4A, KCNK16, MAEA, GCC1-PAX4, PSMD6 and ZFAND3. GLIS3, which is involved in pancreatic beta cell development and insulin gene expression, is known for its association with fasting glucose levels. The evidence of an association with T2D for PEPD and HNF4A has been shown in previous studies. KCNK16 may regulate glucose-dependent insulin secretion in the pancreas. These findings, derived from an east Asian population, provide new perspectives on the etiology of T2D.
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| 20. |
- Davis, S., et al.
(författare)
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SN 2013ai : A Link between Hydrogen-rich and Hydrogen-poor Core-collapse Supernovae
- 2021
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 909:2
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Tidskriftsartikel (refereegranskat)abstract
- We present a study of the optical and near-infrared (NIR) spectra of SN 2013ai along with its light curves. These data range from discovery until 380 days after explosion. SN 2013ai is a fast declining Type II supernova (SN II) with an unusually long rise time, 18.9 2.7 days in the V-band, and a bright V-band peak absolute magnitude of -18.7 0.06 mag. The spectra are dominated by hydrogen features in the optical and NIR. The spectral features of SN 2013ai are unique in their expansion velocities, which, when compared to large samples of SNe II, are more than 1,000 km s(-1) faster at 50 days past explosion. In addition, the long rise time of the light curve more closely resembles SNe IIb rather than SNe II. If SN 2013ai is coeval with a nearby compact cluster, we infer a progenitor zero-age main-sequence mass of similar to 17 M. After performing light-curve modeling, we find that SN 2013ai could be the result of the explosion of a star with little hydrogen mass, a large amount of synthesized Ni-56, 0.3-0.4 M, and an explosion energy of 2.5-3.0 x 10(51) erg. The density structure and expansion velocities of SN 2013ai are similar to those of the prototypical SN IIb, SN 1993J. However, SN 2013ai shows no strong helium features in the optical, likely due to the presence of a dense core that prevents the majority of gamma-rays from escaping to excite helium. Our analysis suggests that SN 2013ai could be a link between SNe II and stripped-envelope SNe.
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| 21. |
- Gunnarsdottir, Sunna Lu Xi, et al.
(författare)
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The use of Intra Aortic Balloon Pump in Coronary Artery Bypass Graft Surgery
- 2020
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Ingår i: Laeknabladid. - : LAEKNAFELAG ISLANDS-ICELANDIC MEDICAL ASSOC. - 0023-7213 .- 1670-4959. ; 106:2, s. 63-70
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Intra-aortic balloon pump (IABP) is a mechanical device that increases cardiac output by increasing diastolic blood flow to the coronary arteries and lowers the afterload of the left ventricle in systole. IABP is primarily used in acute heart failure, that includes patients that have to undergo coronary artery bypass grafting (CABG). Its usage, however, in cardiac surgery has been declining with ongoing controversy regarding its benefits. The aim of this study was to assess the use and indications and outcome of IABP related to CABG surgery. Material and Methods: The study was retrospective and included 2177 patients that underwent CABG at Landspitali during 2001-2018. We compared those who received an IABP with controls, using uni- and multivariate analysis. Long term survival and complications (major adverse cardiovascular and cerebral events, MACCE) was estimated with Kaplan-Meier method. Results: A total of 99 (4.5%) patients received an IABP. The incidence was highest in 2006 (8.9%) and lowest in 2001 (1.7%), but the incidence did not change during the study period (p=0.90). Most patients received the pump before (58.6%) or during (34.3%) CABG, but only 6.1% after surgery. Complication rate was 14.1%, with bleeding from the insertion site in the groin being the most common complication. Thirty day mortality was higher in the IABP group compared with controls (22.2% vs 1.3%, p<0.001) and both 5-year survival (56.4% vs 91.5%, 95% CI: 0.47-0.67) and 5-year MACCE-free survival (46.9% vs 83.0%, 95% CI: 0.38-0.58) were inferior. Conclusions: Less than 5% of patients received IABP in relation to CABG in Iceland and the rate hasn't changed much for the last 18 years. Both the complication rate and 30-day mortality was higher in patients in IABP group and both the long term and MACCE-free survival was much worse, probably mostly related to worse overall clinical condition of the patient that received IABP.
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| 22. |
- Han, Mengyao, et al.
(författare)
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High Spectral Efficiency Long-wave Infrared Free-Space Optical Transmission with Multilevel Signals
- 2023
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Ingår i: Journal of Lightwave Technology. - : Institute of Electrical and Electronics Engineers (IEEE). - 0733-8724 .- 1558-2213. ; 41:20, s. 6514-
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Tidskriftsartikel (refereegranskat)abstract
- This study explores the potential of long-wave infrared free-space optical (FSO) transmission that leverages multilevel signals to attain high spectral efficiency. The FSO transmission system consists of a directly modulated-quantum cascade laser (DM-QCL) operating at 9.15 μm and a mercury cadmium telluride (MCT) detector. To fully understand the system, we conduct measurements on the DM-QCL chip and MCT detector and assess the overall amplitude response of the DM-QCL, MCT detector, and all electrical components. We apply various signals, including on-off keying (OOK), 4-level pulse amplitude modulation (PAM4), 6-level PAM (PAM6), and 8-level PAM (PAM8) to maximize the bit rate and spectral efficiency of the FSO transmission. Through a two-dimensional sweeping of the laser bias current and MCT detector photovoltage, we optimize the transmission performance. At the optimal operation point, the FSO system achieved impressive results which are up to 6 Gbaud OOK, 3.5 Gbaud PAM4, 3 Gbaud PAM6, and 2.7 Gbaud PAM8 signal transmissions, with a bit error rate performance below 6.25% overhead hard decision-forward error correction limit when the DM-QCL operates at 10 °C. We also evaluate the eye diagrams and stability of the system to showcase its remarkable transmission performance. Our findings suggest that the DMQCL and MCT detector-based FSO transceivers offer a highly competitive solution for the next generation of optical wireless communication systems
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| 23. |
- Han, Mengyao, et al.
(författare)
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High Spectral Efficiency Long-Wave Infrared Free-Space Optical Transmission With Multilevel Signals
- 2023
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Ingår i: Journal of Lightwave Technology. - : Institute of Electrical and Electronics Engineers (IEEE). - 0733-8724 .- 1558-2213. ; 41:20, s. 6514-6520
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Tidskriftsartikel (refereegranskat)abstract
- This study explores the potential of long-wave infrared free-space optical (FSO) transmission that leverages multilevel signals to attain high spectral efficiency. The FSO transmission system consists of a directly modulated-quantum cascade laser (DM-QCL) operating at 9.15 mu m and a mercury cadmium telluride (MCT) detector. To fully understand the system, we conduct measurements on the DM-QCL chip and MCT detector and assess the overall amplitude response of the DM-QCL, MCT detector, and all electrical components. We apply various signals, including on-off keying (OOK), 4-level pulse amplitude modulation (PAM4), 6-level PAM (PAM6), and 8-level PAM (PAM8) to maximize the bit rate and spectral efficiency of the FSO transmission. Through a two-dimensional sweeping of the laser bias current and MCT detector photovoltage, we optimize the transmission performance. At the optimal operation point, the FSO system achieved impressive results which are up to 6 Gbaud OOK, 3.5 Gbaud PAM4, 3 Gbaud PAM6, and 2.7 Gbaud PAM8 signal transmissions, with a bit error rate performance below 6.25% overhead hard decision-forward error correction limit when the DM-QCL operates at 10 degrees C. We also evaluate the eye diagrams and stability of the system to showcase its remarkable transmission performance. Our findings suggest that the DM-QCL and MCT detector-based FSO transceivers offer a highly competitive solution for the next generation of optical wireless communication systems.
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| 24. |
- Han, Mengyao, et al.
(författare)
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Long-Wave Infrared Discrete Multitone Free-Space Transmission Using a 9.15-μm Quantum Cascade Laser
- 2023
-
Ingår i: IEEE Photonics Technology Letters. - : Institute of Electrical and Electronics Engineers Inc.. - 1041-1135 .- 1941-0174. ; 35:9, s. 489-492
-
Tidskriftsartikel (refereegranskat)abstract
- A free-space optical (FSO) transmission system is experimentally demonstrated in the long-wave infrared (LWIR, 9.15μ m ) using a directly modulated quantum cascade laser (DM-QCL) and a commercial mercury-cadmium-telluride infrared photovoltaic detector. At room temperature, the DM-QCL is current-modulated by discrete multitone signals pre-processed with bit-/power-loading. Up to 5.1 Gbit/s data rate is achieved with bit error rate performance below the 6.25% overhead hard-decision forward error correction limit of 4.5× 10-3 , enabled by a frequency domain equalizer. The stability study of the FSO system is also performed at multiple temperature values. This study can provide a valuable reference for future terrestrial and space communications.
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| 25. |
- Hu, Kejia, et al.
(författare)
-
Neuroendocrine pathways and breast cancer progression : a pooled analysis of somatic mutations and gene expression from two large breast cancer cohorts
- 2022
-
Ingår i: BMC Cancer. - : BioMed Central. - 1471-2407. ; 22:1
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Experimental studies indicate that neuroendocrine pathways might play a role in progression of breast cancer. We aim to test the hypothesis that somatic mutations in the genes of neuroendocrine pathways influence breast cancer prognosis, through dysregulated gene expression in tumor tissue.METHODS: We conducted an extreme case-control study including 208 breast cancer patients with poor invasive disease-free survival (iDFS) and 208 patients with favorable iDFS who were individually matched on molecular subtype from the Breast Cancer Cohort at West China Hospital (WCH; N = 192) and The Cancer Genome Atlas (TCGA; N = 224). Whole exome sequencing and RNA sequencing of tumor and paired normal breast tissues were performed. Adrenergic, glucocorticoid, dopaminergic, serotonergic, and cholinergic pathways were assessed for differences in mutation burden and gene expression in relation to breast cancer iDFS using the logistic regression and global test, respectively.RESULTS: In the pooled analysis, presence of any somatic mutation (odds ratio = 1.66, 95% CI: 1.07-2.58) of the glucocorticoid pathway was associated with poor iDFS and a two-fold increase of tumor mutation burden was associated with 17% elevated odds (95% CI: 2-35%), after adjustment for cohort membership, age, menopausal status, molecular subtype, and tumor stage. Differential expression of genes in the glucocorticoid pathway in tumor tissue (P = 0.028), but not normal tissue (P = 0.701), was associated with poor iDFS. Somatic mutation of the adrenergic and cholinergic pathways was significantly associated with iDFS in WCH, but not in TCGA.CONCLUSION: Glucocorticoid pathway may play a role in breast cancer prognosis through differential mutations and expression. Further characterization of its functional role may open new avenues for the development of novel therapeutic targets for breast cancer.
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| 26. |
- Hua, Kuo-Tai, et al.
(författare)
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N-α-acetyltransferase 10 protein suppresses cancer cell metastasis by binding PIX proteins and inhibiting Cdc42/Rac1 activity
- 2011
-
Ingår i: Cancer Cell. - : Cell Press. - 1535-6108 .- 1878-3686. ; 19:2, s. 218-231
-
Tidskriftsartikel (refereegranskat)abstract
- N-α-acetyltransferase 10 protein, Naa10p, is an N-acetyltransferase known to be involved in cell cycle control. We found that Naa10p was expressed lower in varieties of malignancies with lymph node metastasis compared with non-lymph node metastasis. Higher Naa10p expression correlates the survival of lung cancer patients. Naa10p significantly suppressed migration, tumor growth, and metastasis independent of its enzymatic activity. Instead, Naa10p binds to the GIT-binding domain of PIX, thereby preventing the formation of the GIT-PIX-Paxillin complex, resulting in reduced intrinsic Cdc42/Rac1 activity and decreased cell migration. Forced expression of PIX in Naa10-transfected tumor cells restored the migration and metastasis ability. We suggest that Naa10p functions as a tumor metastasis suppressor by disrupting the migratory complex, PIX-GIT- Paxillin, in cancer cells.
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| 27. |
- Jia, Ting, et al.
(författare)
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Malaria parasites and related haemosporidians cause mortality in cranes : A study on the parasites diversity, prevalence and distribution in Beijing Zoo
- 2018
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Ingår i: Malaria Journal. - : Springer Science and Business Media LLC. - 1475-2875. ; 17:1
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Malaria parasites and related haemosporidian parasites are widespread and may cause severe diseases in birds. These pathogens should be considered in projects aiming breeding of birds for purposes of sustained ex situ conservation. Cranes are the 'flagship species' for health assessment of wetland ecosystems, and the majority of species are endangered. Malaria parasites and other haemosporidians have been reported in cranes, but the host-parasite relationships remain insufficiently understood. Morbidity of cranes due to malaria has been reported in Beijing Zoo. This study report prevalence, diversity and distribution of malaria parasites and related haemosporidians in cranes in Beijing Zoo and suggest simple measures to protect vulnerable individuals. Methods: In all, 123 cranes (62 adults and 61 juveniles) belonging to 10 species were examined using PCR-based testing and microscopic examination of blood samples collected in 2007-2014. All birds were maintained in open-air aviaries, except for 19 chicks that were raised in a greenhouse with the aim to protect them from bites of blood-sucking insects. Bayesian phylogenetic analysis was used to identify the closely related avian haemosporidian parasites. Results: Species of Plasmodium (5 lineages), Haemoproteus (1) and Leucocytozoon (2) were reported. Malaria parasites predominated (83% of all reported infections). The overall prevalence of haemosporidians in juveniles was approximately seven-fold higher than in adults, indicating high susceptibility of chicks and local transmission. Juvenile and adult birds hosted different lineages of Plasmodium, indicating that chicks got infection from non-parent birds. Plasmodium relictum (pSGS1) was the most prevalent malaria parasite. Mortality was not reported in adults, but 53% of infected chicks died, with reports of co-infection with Plasmodium and Leucocytozoon species. All chicks maintained in the greenhouse were non-infected and survived. Species of Leucocytozoon were undetectable by commonly used PCR protocol, but readily visible in blood films. Conclusion: Crane chicks often die due to malaria and Leucocytozoon infections, which they likely gain from wild free-living birds in Beijing Zoo. Molecular diagnostics of crane Leucocytozoon parasites needs improvement. Because the reported infections are mainly chick diseases, the authors recommend maintaining of juvenile birds in vector-free facilities until the age of approximately 6 months before they are placed in open-air aviaries.
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| 28. |
- Jiang, Kang, et al.
(författare)
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Single platinum atoms embedded in nanoporous cobalt selenide as electrocatalyst for accelerating hydrogen evolution reaction
- 2019
-
Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10
-
Tidskriftsartikel (refereegranskat)abstract
- Designing efficient electrocatalysts for hydrogen evolution reaction is significant for renewable and sustainable energy conversion. Here, we report single-atom platinum decorated nanoporous Co0.85Se (Pt/np-Co0.85Se) as efficient electrocatalysts for hydrogen evolution. The achieved Pt/np-Co0.85Se shows high catalytic performance with a near-zero onset overpotential, a low Tafel slope of 35 mV dec(-1), and a high turnover frequency of 3.93 s(-1) at -100 mV in neutral media, outperforming commercial Pt/C catalyst and other reported transition-metal-based compounds. Operando X-ray absorption spectroscopy studies combined with density functional theory calculations indicate that single-atom platinum in Pt/np-Co0.85Se not only can optimize surface states of Co0.85Se active centers under realistic working conditions, but also can significantly reduce energy barriers of water dissociation and improve adsorption/desorption behavior of hydrogen, which synergistically promote thermodynamics and kinetics. This work opens up further opportunities for local electronic structures tuning of electrocatalysts to effectively manipulate its catalytic properties by an atomic-level engineering strategy.
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| 29. |
- Joharifar, Mahdieh, et al.
(författare)
-
16.9 Gb/s Single-Channel LWIR FSO Data Transmission with Directly Modulated QCL and MCT Detector
- 2024
-
Ingår i: <em>2024 Optical Fiber Communications Conference and Exhibition, OFC 2024 - Proceedings</em>. - : Institute of Electrical and Electronics Engineers Inc.. - 9781957171326
-
Konferensbidrag (refereegranskat)abstract
- We experimentally demonstrate a room-temperature LWIR FSO link with a 9.1-μm directly modulated QCL and an MCT detector. Net bitrate of up to 16.9 Gb/s is achieved at both 15°C and 20°C over a 1-meter distance.
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| 30. |
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| 31. |
- Joharifar, Mahdieh, et al.
(författare)
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Advancing LWIR FSO communication through high-speed multilevel signals and directly modulated quantum cascade lasers
- 2024
-
Ingår i: Optics Express. - : Optica Publishing Group. - 1094-4087. ; 32:17, s. 29138-29148
-
Tidskriftsartikel (refereegranskat)abstract
- This study investigates the potential of long-wave infrared (LWIR) free-space optical (FSO) transmission using multilevel signals to achieve high spectral efficiency. The FSO transmission system includes a directly modulated-quantum cascade laser (DM-QCL) operating at 9.1 µm and a mercury cadmium telluride (MCT) detector. The laser operated at the temperature settings of 15°C and 20°C. The experiment was conducted over a distance of 1 m and in a lab as a controlled environment. We conduct small-signal characterization of the system, including the DM-QCL chip and MCT detector, evaluating the end-to-end response of both components and all associated electrical elements. For large-signal characterization, we employ a range of modulation formats, including non-return-to-zero on-off keying (NRZ-OOK), 4-level pulse amplitude modulation (PAM4), and 6-level PAM (PAM6), with the objective of optimizing both the bit rate and spectral efficiency of the FSO transmission by applying pre- and post-processing equalization. At 15°C, the studied LWIR FSO system achieves net bitrates of 15 Gbps with an NRZ-OOK signal and 16.9 Gbps with PAM4, both below the 6.25% overhead hard decision-forward error correction (6.25%-OH HD-FEC) limit, and 10 Gbps NRZ-OOK below the 2.7% overhead Reed-Solomon RS(528,514) pre-FEC (KR-FEC limit). At 20°C, we obtained net bitrates of 14.1 Gbps with NRZ-OOK, 16.9 Gbps with PAM4, and 16.4 Gbps with PAM6. Furthermore, we evaluate the BER performance as a function of the decision feedback equalization (DFE) tap number to explore the role of equalization in enhancing signal fidelity and reducing errors in FSO transmission. Our findings accentuate the competitive potential of DM-QCL and MCT detector-based FSO transceivers with digital equalization for the next generation of FSO communication systems.
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| 32. |
- Joharifar, Mahdieh, et al.
(författare)
-
Advancing LWIR FSO communication through high-speed multilevel signals and directly modulated quantum cascade lasers
- 2024
-
Ingår i: Optics Express. - : Optica Publishing Group (formerly OSA). - 1094-4087. ; 32:17, s. 29138-29148
-
Tidskriftsartikel (refereegranskat)abstract
- This study investigates the potential of long-wave infrared (LWIR) free-space optical (FSO) transmission using multilevel signals to achieve high spectral efficiency. The FSO transmission system includes a directly modulated-quantum cascade laser (DM-QCL) operating at 9.1 µm and a mercury cadmium telluride (MCT) detector. The laser operated at the temperature settings of 15°C and 20°C. The experiment was conducted over a distance of 1 m and in a lab as a controlled environment. We conduct small-signal characterization of the system, including the DM-QCL chip and MCT detector, evaluating the end-to-end response of both components and all associated electrical elements. For large-signal characterization, we employ a range of modulation formats, including non-return-to-zero on-off keying (NRZ-OOK), 4-level pulse amplitude modulation (PAM4), and 6-level PAM (PAM6), with the objective of optimizing both the bit rate and spectral efficiency of the FSO transmission by applying pre- and post-processing equalization. At 15°C, the studied LWIR FSO system achieves net bitrates of 15 Gbps with an NRZ-OOK signal and 16.9 Gbps with PAM4, both below the 6.25% overhead hard decision-forward error correction (6.25%-OH HD-FEC) limit, and 10 Gbps NRZ-OOK below the 2.7% overhead Reed-Solomon RS(528,514) pre-FEC (KR-FEC limit). At 20°C, we obtained net bitrates of 14.1 Gbps with NRZ-OOK, 16.9 Gbps with PAM4, and 16.4 Gbps with PAM6. Furthermore, we evaluate the BER performance as a function of the decision feedback equalization (DFE) tap number to explore the role of equalization in enhancing signal fidelity and reducing errors in FSO transmission. Our findings accentuate the competitive potential of DM-QCL and MCT detector-based FSO transceivers with digital equalization for the next generation of FSO communication systems.
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| 33. |
- Joharifar, Mahdieh, et al.
(författare)
-
High-Speed 9.6-μm Long-Wave Infrared Free- Space Transmission with a Directly-Modulated QCL and a Fully-Passive QCD
- 2023
-
Ingår i: Journal of Lightwave Technology. - : Institute of Electrical and Electronics Engineers Inc.. - 0733-8724 .- 1558-2213. ; 41:4, s. 1087-
-
Tidskriftsartikel (refereegranskat)abstract
- Free-space optics (FSO) in the mid-infrared (mid- IR) contains rich spectral resources for future ultrahigh-speed wireless communications yet is currently under-exploited. Two atmospheric transmission windows at the mid-IR, namely, the mid-wave IR (MWIR, 3-5 µm) and the long-wave IR (LWIR, 8-12 µm), show great potential in supporting free-space communications for both terrestrial and space application scenarios. Particularly, the LWIR signal with a longer wavelength has high intrinsic robustness against aerosols' scattering and turbulence-induced scintillation and beam broadening effects, which are the main concerns hindering the wide deployment of practical FSO systems. In this context, high-bandwidth semiconductor-based mid-IR FSO transceivers will be desirable to meet the requirements of low energy consumption and small footprints for large-volume development and deployment. Quantum cascade devices, including quantum cascade lasers (QCLs) and quantum cascade detectors (QCDs), appear promising candidates to fulfill this role. In this work, we report a high-speed LWIR FSO transmission demonstration with a 9.6-µm directly-modulated (DM)-QCL and a fully passive QCD without any active cooling or bias voltage. Up to 8 Gb/s, 10 Gb/s, and 11 Gb/s signal transmissions are achieved when operating the DM- QCL at 10°C, 5°C, and 0°C, respectively. These results indicate a significant step towards an envisioned fully-connected mid-IR FSO solution empowered by the quantum cascade semiconductor devices.
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| 34. |
- Junaid, Muhammad, et al.
(författare)
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Effects of N2 Partial Pressure on Growth, Structure, and Optical Properties of GaN Nanorods Deposited by Liquid-Target Reactive Magnetron Sputter Epitaxy
- 2018
-
Ingår i: Nanomaterials. - Basel, Switzerland : MDPI. - 2079-4991. ; 8:4
-
Tidskriftsartikel (refereegranskat)abstract
- GaN nanorods, essentially free from crystal defects and exhibiting very sharp band-edge luminescence, have been grown by reactive direct-current magnetron sputter epitaxy onto Si (111) substrates at a low working pressure of 5 mTorr. Upon diluting the reactive N2 working gas with a small amount of Ar (0.5 mTorr), we observed an increase in the nanorod aspect ratio from 8 to ~35, a decrease in the average diameter from 74 to 35 nm, and a two-fold increase in nanorod density. With further dilution (Ar = 2.5 mTorr), the aspect ratio decreased to 14, while the diameter increased to 60 nm and the nanorod density increased to a maximum of 2.4 × 109 cm−2. Yet, lower N2 partial pressures eventually led to the growth of continuous GaN films. The observed morphological dependence on N2 partial pressure is explained by a change from N-rich to Ga-rich growth conditions, combined with reduced GaN-poisoning of the Ga-target as the N2 gas pressure is reduced. Nanorods grown at 2.5 mTorr N2 partial pressure exhibited a high intensity 4 K photoluminescence neutral donor bound exciton transitions (D0XA) peak at ~3.479 eV with a full-width-at-half-maximum of 1.7 meV. High-resolution transmission electron microscopy corroborated the excellent crystalline quality of the nanorods.
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| 35. |
- Lin, Chang, et al.
(författare)
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Characteristics of air-water interface of air pockets in a conduit
- 2014
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Konferensbidrag (refereegranskat)abstract
- The presence of air pockets in a pipeline system often causes reduction in its efficiency and shortens its service life. Potential safety hazards arise in some cases from air blowout or blowback. It is thus of interest to examine the water flow field at air pockets and the feature of water-air interface. This study applied flow visualization technique and high-speed particle image velocimetry (HSPIV) to investigate characteristics of flow fields at stationary solitary air pockets in a fully-developed horizontal pipe flow. Experiments were performed in a Plexiglas pipe having an inner diameter of 9.6 cm, with Titanium dioxide powder as tracer for measurements. The results show that a horseshoe vortex and reverse flow pattern existed both up- and downstream of the air pockets. A deformable air pocket in the turbulent flow caused streamwisely a random movement of both stagnation and separation points around their mean positions. An intermittent flow re-attachment occurred also downstream of the mean separation point. The air-water interface was not stationary but moved with the adjacent water flow.
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| 36. |
- Lin, C., et al.
(författare)
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Study on water flow field around a stationary air bubble attached at the top wall of a Circular Pipe
- 2013
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Ingår i: Computational methods in multiphase flow VII. - : WIT Press. - 9781845647346 ; , s. 323-338
-
Konferensbidrag (refereegranskat)abstract
- The presence of bubbles in a pipeline is thought to be one of the reasons to cause the hydraulic-electrical and hydraulic-mechanical facility systems to lose their efficiency. From previous research, the bubble also reduces the effective pipe cross section, which results in a reduction in pipe capacity. The efficiency and service life of pumps and turbines are reduced and shortened consequently. It may even create the interruption of the flow field within blowout phenomenon. As a result, the presence of a bubble in the pipeline is anticipated to create potential hazards. Therefore, it is very interesting to make clear the corresponding variation of a water flow field around a stationary air bubble attached at the top inner-wall of pipe due to the surface problems in contact mechanism of these three phases among the solid wall of pipe, stationary air bubble, and ambient water flow. This study applied flow visualization techniques and high time-resolved PIV to investigate the characteristics of a flow field around a stationary bubble in a fully-developed horizontal pipe flow. Experiments were carried out in a pipe having a constant inner diameter of 9.60 cm and a length of 260.0 cm, yet varied with different bubble volumes (or lengths). Two settling water chambers with different still water levels were connected to both ends of the circular pipe. Titanium dioxide powder being uniformly dispersed in the pipe flow was used as a tracer both for flow visualization tests and for PIV measurements. The results show that a horseshoe vortex and reverse flow at the upstream and downstream of the bubble respectively are commonly seen in all test cases. The experimental results also show that the shape and volume of a bubble highly affect the flow field in the surroundings of the stationary air bubble. Since the bubble surface is slippery, flow velocity exists on the surface of a bubble. As a result, the reverse flow at the end of a long-flat bubble would not affect the velocity on the bubble surface.
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| 37. |
- Lin, Chang, et al.
(författare)
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Visualizing Conduit Flows around Solitary Air Pockets
- 2014
-
Ingår i: Journal of engineering mechanics. - : American Society of Civil Engineers (ASCE). - 0733-9399 .- 1943-7889. ; 141:5
-
Tidskriftsartikel (refereegranskat)abstract
- Understanding flow characteristics around air pockets is fundamental in the study of air entrainment and transport in pipelines. This study deals with the use of flow visualization technique (FVT) and high-speed particle image velocimetry (HSPIV) in exploration of the characteristics around stationary air pockets in horizontal-pipe flow. The air-pocket volume varies from 0 to 10.0 mL, and the air pocket is injected into a fully developed turbulent flow with Reynolds numbers between 17,000 and 18,400. In the plane of symmetry, the main flow features include (1) a horseshoe vortex upstream, (2) a stagnation point on the frontal interface, (3) a separation point and a separated shear layer beneath, (4) a reattached shear layer downstream of the reattachment point (for air-pocket volumes greater than 2.0 mL), and (5) a reverse-flow region downstream. The deformable air pocket in the turbulent flow causes streamwise random movements of both the stagnation and separation points around their mean positions. The flow pattern is categorized based on the occurrence of either separated flow or flow reattachment. Fully separated flow (Mode I) occurs at air-pocket volumes less than 2.0 mL. Intermittently reattached flow (Mode II) occurs if the volume is within 2.0–5.0 mL. Fully reattached flow (Mode III) is evident at volumes greater than 5.0 mL. Water particles on the air-pocket surface move with the adjacent flow, thus forming a slip boundary. The evolution of mean streamwise velocity beneath the air pocket demonstrates the formation of either a separated or a reattached shear layer. Using nonlinear regression analysis, appropriate characteristic velocity and length scales are determined to obtain similarity profiles in the separated shear layer beneath.
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| 38. |
- Lin, Wei Cheng, et al.
(författare)
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Effect of energy bandgap and sacrificial agents of cyclopentadithiophene-based polymers for enhanced photocatalytic hydrogen evolution
- 2021
-
Ingår i: Applied Catalysis B: Environmental. - : Elsevier BV. - 0926-3373. ; 298
-
Tidskriftsartikel (refereegranskat)abstract
- A library of donor-acceptor system consisting of cyclopentadithiophene-based polymer photocatalysts have been designed and synthesized. Among all photocatalysts, the active PCPDTBSO achieved hydrogen evolution rates of 24.6 mmol h–1 g–1 with apparent quantum yields of 8.7 % at 500 nm. More importantly, combined the results of photocatalytic efficiency, apparent quantum yield, the time-resolved fluorescence decay spectra, the steady-state photoluminescence spectra, and the transient absorption spectroscopy, and the oxidation potentials of sacrificial donors and protons reduction potentials in different pH values, we confirmed the concept that ascorbic acid is a suitable sacrificial donor for narrow bandgap polymers and triethylamine is a suitable sacrificial donor for wide bandgap polymers owing to the existence of the optimal thermodynamic driving force. We believed this study would be advantageous for the selection of photocatalysts and sacrificial donors for hydrogen production.
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| 39. |
- Lin, Wei Ju, et al.
(författare)
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Deterministic Loading of Microwaves onto an Artificial Atom Using a Time-Reversed Waveform
- 2022
-
Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 22:20, s. 8137-8142
-
Tidskriftsartikel (refereegranskat)abstract
- Loading quantum information deterministically onto a quantum node is an important step toward a quantum network. Here, we demonstrate that coherent-state microwave photons with an optimal temporal waveform can be efficiently loaded onto a single superconducting artificial atom in a semi-infinite one-dimensional (1D) transmission-line waveguide. Using a weak coherent state (the number of photons (N) contained in the pulse ≪1) with an exponentially rising waveform, whose time constant matches the decoherence time of the artificial atom, we demonstrate a loading efficiency of 94.2% ± 0.7% from 1D semifree space to the artificial atom. The high loading efficiency is due to time-reversal symmetry: the overlap between the incoming wave and the time-reversed emitted wave is up to 97.1% ± 0.4%. Our results open up promising applications in realizing quantum networks based on waveguide quantum electrodynamics.
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| 40. |
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| 41. |
- Lu, Meng, et al.
(författare)
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Zoonotic risk assessment among farmed mammals
- 2023
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Ingår i: Cell. - : Elsevier. - 0092-8674 .- 1097-4172. ; 186:9, s. 2040-2040.e1
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Farmed mammals may act as hosts for zoonotic viruses that can cause disease outbreaks in humans. This SnapShot shows which farmed mammals, and to what extent, are of particular risk of harboring and spreading viruses from viral families that are commonly associated with zoonotic disease. It also discusses genome surveillance methods and biosafety measures.
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| 42. |
- Lu, Ting, et al.
(författare)
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Post-crosslinking towards stimuli-responsive sodium alginate beads for the removal of dye and heavy metals
- 2015
-
Ingår i: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 133, s. 587-595
-
Tidskriftsartikel (refereegranskat)abstract
- Post-crosslinking as a new strategy to prepare sodium alginate (SA) beads with controllable swelling behavior, pH sensitivity and adsorption capacity was developed by using the solution of glutaraldehyde (GA), acetic acid and hydrochloric acid as the coagulating agent, for which could be used to fabricate polysaccharide beads in a large scale. Fourier transform infrared spectroscopy and thermogravimetric analysis convinced the successful cross-linking of SA by GA. The macro-porous structures of the beads were observed by scanning electron microscopy. Both acetic acid and hydrochloric acid had great effects on the swelling behavior and pH sensitivity of the SA beads. The SA beads could adsorb cationic dye (methylene blue) as high as 572 mg/g and other metal ions (Cu2+, Ag+ and Fe3+). The adsorption processes fitted well with the pseudo-second-order kinetic model and the Freundlich isotherm. The large-scale production of SA beads with tunable properties opens a new route to industrially utilize polysaccharide beads in wastewater treatments, intelligent separation and so on.
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| 43. |
- Lu, Yichen, et al.
(författare)
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Analytical Method of Traffic Conflict at Urban Road Intersections Based on Risk Region
- 2021
-
Ingår i: Tongji Daxue Xuebao/Journal of Tongji University. - 0253-374X. ; 49:7, s. 941-948
-
Tidskriftsartikel (refereegranskat)abstract
- A two-stage method of traffic conflict analysis was proposed based on risk region. By using the inD dataset, traffic conflicts were recognized with the calculation of time to risk region(tTTR), and then the degree of traffic conflict risk was judged by risk region duration. Compared with the method based on time-to-collision(tTTC), the proposed method can not only identify rear-end conflicts and crossing conflicts more effectively, but also characterize the degree of traffic conflict risk at different times.
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| 44. |
- Lu, Yao, et al.
(författare)
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Directly Modulated VCSELs with Frequency Comb Injection for Parallel Communications
- 2020
-
Ingår i: Journal of Lightwave Technology. - : Institute of Electrical and Electronics Engineers (IEEE). - 0733-8724 .- 1558-2213. ; , s. 1-1
-
Tidskriftsartikel (refereegranskat)abstract
- We propose a comb-locked multi-channel transmitter with high-speed VCSELs injection-locked by an optical frequency comb. VCSEL dynamics are analyzed with various injection parameters including number of comb tones, frequency detuning and injection ratio. We evaluate the performance of filtering and amplification effect when multiple comb tones injection into single VCSEL, and estimate the transmission performance considering the reflection from VCSEL. Compared to intrinsic parameters of VCSEL, a 2-fold increase in frequency response and a 2.6 10 4-fold reduction in linewidth have been verified experimentally when the bandwidth-limited VCSEL locked to an incident comb line. 14-Gb/s single-lane transmission is demonstrated through 20 km single-mode fiber based on a 3.4-GHz VCSEL without any dispersion compensation. The similar performance can be achieved for all generated 25 comb tones, verifying a potential high-capacity transmitter with distinct feature of two-dimensional VCSELs
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| 45. |
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| 46. |
- Luo, Shijian, et al.
(författare)
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RoamFab : A Design Tool for Reconfiguring Parameterized Mechanisms to 3D Models With Structural Optimization
- 2023
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Ingår i: International Journal of Human-Computer Interaction. - : Informa UK Limited. - 1044-7318 .- 1532-7590. ; 39:19, s. 3702-3716
-
Tidskriftsartikel (refereegranskat)abstract
- Creating personalized 3D printing objects has become increasingly popular with the advance in end-user modeling tools and fabrication techniques. However, it remains challenging for novice makers to design and fabricate functional objects with mechanical motion such as linear or rotational. To empower users to add mechanical movements to their models for particular needs, we first investigate the commonly used 3D printable mechanisms and parameterize four mechanical primitives. We then provide a computational approach to reconfigure the mechanical primitives to user-provided 3D models, with an underlying structural optimization procedure according to a specified bending force. We further showcase a set of design examples and conduct a user study to demonstrate the potential of our approach in creating personalized functional artifacts.
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| 47. |
- Luo, Yifei, et al.
(författare)
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Technology Roadmap for Flexible Sensors
- 2023
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Ingår i: ACS Nano. - : American Chemical Society. - 1936-0851 .- 1936-086X. ; 17:6, s. 5211-5295
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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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- Pang, Xiaodan, Dr., et al.
(författare)
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Bridging the Terahertz Gap: Photonics-assisted Free-Space Communications from the Submillimeter-Wave to the Mid-Infrared
- 2022
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Ingår i: Journal of Lightwave Technology. - : Institute of Electrical and Electronics Engineers (IEEE). - 0733-8724 .- 1558-2213. ; , s. 1-1
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Tidskriftsartikel (refereegranskat)abstract
- Since about one and half centuries ago, at the dawn of modern communications, the radio and the optics have been two separate electromagnetic spectrum regions to carry data. Differentiated by their generation/detection methods and propagation properties, the two paths have evolved almost independently until today. The optical technologies dominate the long-distance and high-speed terrestrial wireline communications through fiber-optic telecom systems, whereas the radio technologies have mainly dominated the short- to medium-range wireless scenarios. Now, these two separate counterparts are both facing a sign of saturation in their respective roadmap horizons, particularly in the segment of free-space communications. The optical technologies are extending into the mid-wave and long-wave infrared (MWIR and LWIR) regimes to achieve better propagation performance through the dynamic atmospheric channels. Radio technologies strive for higher frequencies like the millimeter-wave (MMW) and sub-terahertz (sub-THz) to gain broader bandwidth. The boundary between the two is becoming blurred and intercrossed. During the past few years, we witnessed technological breakthroughs in free-space transmission supporting very high data rates, many achieved with the assistance of photonics. This paper focuses on such photonics-assisted free-space communication technologies in both the lower and upper sides of the THz gap and provides a detailed review of recent research and development activities on some of the key enabling technologies. Our recent experimental demonstrations of high-speed free-space transmissions in both frequency regions are also presented as examples to show the system requirements for device characteristics and digital signal processing (DSP) performance.
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