| 1. |
- Menkveld, Albert J., et al.
(författare)
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Nonstandard Errors
- 2024
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Ingår i: JOURNAL OF FINANCE. - : Wiley-Blackwell. - 0022-1082 .- 1540-6261. ; 79:3, s. 2339-2390
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Tidskriftsartikel (refereegranskat)abstract
- In statistics, samples are drawn from a population in a data-generating process (DGP). Standard errors measure the uncertainty in estimates of population parameters. In science, evidence is generated to test hypotheses in an evidence-generating process (EGP). We claim that EGP variation across researchers adds uncertainty-nonstandard errors (NSEs). We study NSEs by letting 164 teams test the same hypotheses on the same data. NSEs turn out to be sizable, but smaller for more reproducible or higher rated research. Adding peer-review stages reduces NSEs. We further find that this type of uncertainty is underestimated by participants.
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| 2. |
- Chen, Baoqing, et al.
(författare)
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The Long Noncoding RNA CCAT2 Induces Chromosomal Instability Through BOP1-AURKB Signaling
- 2020
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Ingår i: Gastroenterology. - : Elsevier BV. - 0016-5085 .- 1528-0012. ; 159:6, s. 2146-2162
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Tidskriftsartikel (refereegranskat)abstract
- Background & AimsChromosomal instability (CIN) is a carcinogenesis event that promotes metastasis and resistance to therapy by unclear mechanisms. Expression of the colon cancer–associated transcript 2 gene (CCAT2), which encodes a long noncoding RNA (lncRNA), associates with CIN, but little is known about how CCAT2 lncRNA regulates this cancer enabling characteristic.MethodsWe performed cytogenetic analysis of colorectal cancer (CRC) cell lines (HCT116, KM12C/SM, and HT29) overexpressing CCAT2 and colon organoids from C57BL/6N mice with the CCAT2 transgene and without (controls). CRC cells were also analyzed by immunofluorescence microscopy, γ-H2AX, and senescence assays. CCAT2 transgene and control mice were given azoxymethane and dextran sulfate sodium to induce colon tumors. We performed gene expression array and mass spectrometry to detect downstream targets of CCAT2 lncRNA. We characterized interactions between CCAT2 with downstream proteins using MS2 pull-down, RNA immunoprecipitation, and selective 2′-hydroxyl acylation analyzed by primer extension analyses. Downstream proteins were overexpressed in CRC cells and analyzed for CIN. Gene expression levels were measured in CRC and non-tumor tissues from 5 cohorts, comprising more than 900 patients.ResultsHigh expression of CCAT2 induced CIN in CRC cell lines and increased resistance to 5-fluorouracil and oxaliplatin. Mice that expressed the CCAT2 transgene developed chromosome abnormalities, and colon organoids derived from crypt cells of these mice had a higher percentage of chromosome abnormalities compared with organoids from control mice. The transgenic mice given azoxymethane and dextran sulfate sodium developed more and larger colon polyps than control mice given these agents. Microarray analysis and mass spectrometry indicated that expression of CCAT2 increased expression of genes involved in ribosome biogenesis and protein synthesis. CCAT2 lncRNA interacted directly with and stabilized BOP1 ribosomal biogenesis factor (BOP1). CCAT2 also increased expression of MYC, which activated expression of BOP1. Overexpression of BOP1 in CRC cell lines resulted in chromosomal missegregation errors, and increased colony formation, and invasiveness, whereas BOP1 knockdown reduced viability. BOP1 promoted CIN by increasing the active form of aurora kinase B, which regulates chromosomal segregation. BOP1 was overexpressed in polyp tissues from CCAT2 transgenic mice compared with healthy tissue. CCAT2 lncRNA and BOP1 mRNA or protein were all increased in microsatellite stable tumors (characterized by CIN), but not in tumors with microsatellite instability compared with nontumor tissues. Increased levels of CCAT2 lncRNA and BOP1 mRNA correlated with each other and with shorter survival times of patients.ConclusionsWe found that overexpression of CCAT2 in colon cells promotes CIN and carcinogenesis by stabilizing and inducing expression of BOP1 an activator of aurora kinase B. Strategies to target this pathway might be developed for treatment of patients with microsatellite stable colorectal tumors.
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| 3. |
- Chen, Zhang, et al.
(författare)
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Making monolayer graphene photoluminescent by electron-beam-activated fluorination approach
- 2023
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Ingår i: Applied Surface Science. - : Elsevier. - 0169-4332 .- 1873-5584. ; 608
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Tidskriftsartikel (refereegranskat)abstract
- The past one and half decades have witnessed a tremendous development of graphene electronics, and the key to the success of graphene is its exceptional properties. The lacking of an inherent bandgap endows graphene with excellent electrical properties but considerably limits its applications in light-emitting and high-performance graphene-based devices. Herein, an approach for the direct writing of semiconducting and photoluminescent fluorinated graphene (C4F) patterns on monolayer graphene by an optimized electron-beam-activated fluorination technique is reported. A series of characterization approaches, such as atomic force microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy were used to demonstrate the successful preparation of C4F for maskless lithography. Specially, a sharp and strong photoluminescence located at the purple light range of ∼380 nm was observed in C4F, demonstrating a desirable semiconducting nature, and the bandgap was further confirmed by follow-up electrical measurements, where the C4F filed-effect transistor exhibited a p-type semiconductor behavior and significantly enhanced on/off ratio. Therefore, this work provides a novel technique for the fabrication of graphene devices for promising electronic and optoelectronic applications, but also opens a route towards the tailoring and engineering of electronic properties of graphene.
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| 4. |
- Liu, Baoqing, et al.
(författare)
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Effect of gas distributor on gas–liquid dispersion and mass transfer characteristics in stirred tank
- 2019
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Ingår i: Chemical Engineering Research and Design. - : Elsevier BV. - 0263-8762. ; 145, s. 314-322
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Tidskriftsartikel (refereegranskat)abstract
- Aiming at the fact that the function of gas distributor is often neglected in the case of high viscosity conditions, a novel spherical micro-orifice gas distributor was proposed and investigated experimentally in water system and non-Newtonian viscous system, respectively. The comparisons of gas–liquid dispersion and mass transfer performance between novel spherical micro-orifice gas distributor and traditional ring distributor were also done. Furthermore, the effects of gas distributors on the gas–liquid dispersion and mass transfer characteristics of three wide-viscosity-range impellers including LDB impeller, FZ impeller and MB impeller were also researched, and an impeller-distributor configuration with good gas–liquid dispersion and mass transfer performance was achieved. The results show that, compared with ring gas distributor, the bubbles dispersed by novel spherical micro-orifice gas distributor are smaller, and the gas holdup and volumetric mass transfer coefficient are relatively higher under the same power consumption per unit volume. Meanwhile, the significant effect of gas distributor geometry on gas dispersion was found for high-viscosity liquid, but not relevant for low-viscosity batches. In addition, compared with other impeller-distributor configurations, the configuration consisting of FZ impeller and novel spherical micro-orifice gas distributor can achieve greater global gas holdup and higher oxygen mass transfer rate, which is recommended especially in viscous system with high gas flow rate. The research is beneficial to promote the application of novel spherical micro-orifice gas distributor in stirred tanks.
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| 5. |
- Liu, Baoqing, et al.
(författare)
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Experimental Investigation on Drawdown of Floating Particles in Viscous Systems Driven by Coaxial Mixers
- 2019
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Ingår i: Industrial and Engineering Chemistry Research. - : American Chemical Society (ACS). - 0888-5885 .- 1520-5045. ; 58, s. 11060-11071
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Tidskriftsartikel (refereegranskat)abstract
- In view of the current situation of single form and low efficiency, a coaxial mixer with wide adaptability was combined with the drawdown of floating particles in viscous systems, and the effects of operation mode, impeller type, impeller diameter, impeller submergence, system viscosity, solid concentration and particle size were investigated experimentally. It is found that the coaxial mixer under corotation mode can achieve the critical drawdown of floating particles with lower speed and power than the corresponding single-shaft mixer, and the advantage becomes more obvious with increasing system viscosity and solid volume fraction. Under the same conditions, compared with the axial and radial flow impellers, the mixed flow impeller with down-pumping mode can effectively draw the floating particles down with the lowest critical speed and power. Moreover, a larger impeller diameter and smaller impeller submergence are recommended for the drawdown of floating particles, but the impeller diameter should not exceed half of the vessel diameter.
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| 6. |
- Liu, Baoqing, et al.
(författare)
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Experimental investigation on micromixing characteristics of coaxial mixers in viscous system
- 2020
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Ingår i: Canadian Journal of Chemical Engineering. - : Wiley. - 0008-4034 .- 1939-019X. ; 98:8, s. 1815-1824
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Tidskriftsartikel (refereegranskat)abstract
- An experimental investigation into the micromixing performance of coaxial mixers in a viscous system is reported, in which the iodide-iodate reaction system is chosen to quantitatively characterize the product distributions. The effects of feeding time, feeding position, impeller speed, inner impeller configuration, and operation mode on the segregation index, Xs, are examined. It is revealed that the feeding near the inner impeller benefits micromixing and should be regarded as the preferred position. The presence of the rotating outer impeller causes the micromixing performance of the coaxial mixer to be significantly better than the single-shaft mixer. While an increase in the outer impeller speed has a limited influence on micromixing, the inner impeller speed is the dominant influencing factor, that is, the Xs decreases obviously when the inner impeller speed is increased. On the other hand, the coaxial mixers with multiple and axial inner impellers have a better micromixing performance at the same specific power consumption, PV, than that with single and radial inner impellers. Among the configurations consisting of a Rushton impeller (RT), six-straight-blade turbine impeller (SBT), and six-pitched (45°)-blade turbine impeller (PBT), the Xs of the coaxial mixer is always the smallest at the same PV when the PBT + RT configuration is used as the inner impeller. In addition, it is found that the difference in Xs that results from various operation modes is small in terms of power consumption; however, the co-rotation mode is still recommended for the micromixing of the coaxial mixer due to its excellent performance in general.
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| 7. |
- Liu, Baoqing, et al.
(författare)
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Investigation of gas–liquid dispersion and mass transfer performance of wide-viscosity-range impellers in water solutions of xanthan gum
- 2020
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Ingår i: Chemical Engineering Research and Design. - : Elsevier BV. - 0263-8762. ; 154, s. 60-69
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Tidskriftsartikel (refereegranskat)abstract
- Wide-viscosity-range impellers have extensive demands and applications in process industry. The gas–liquid dispersion and mass transfer characteristics of wide-viscosity-range impellers including Large-double-blade (LDB) impeller, Fullzone (FZ) impeller and Maxblend (MB) impeller in water solutions of xanthan gum were investigated experimentally and compared. The influences of gas flow rate, impeller speed and polymer concentration of liquid on the power consumption, overall gas holdup εg and mass transfer coefficient KLa were also analyzed. On this basis, the appropriate operating parameters and impeller type were determined. The results indicate that with rising flow rate, the higher εg and KLa can be achieved with a drop in power consumption, and a relatively high flow rate is recommended on the premise of guaranteeing the complete dispersal condition in aerated vessel. Higher impeller speed provides better gas–liquid dispersion and mass transfer performance, but results in more power consumption simultaneously. The appropriate impeller speed should be just enough to meet the requirements of εg and KLa. It also is found that the increasing concentration of water solution of xanthan gum adds to the complexity of gas dispersion and mass transfer in aerated vessel. Under the same specific power consumption PV, the εg and KLa are positive and negative correlation with the polymer concentration of liquid, respectively. Specially, when the concentration of water solution of xanthan gum is relatively low, the FZ impeller exhibits the best gas dispersion and mass transfer performance under the same specific power consumption. Nevertheless, the mass transfer performance of FZ impeller deteriorates significant when the concentration of water solution of xanthan gum increases to 1.00 wt%, and the MB impeller becomes the most appropriate impeller type in this condition.
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| 8. |
- Liu, Baoqing, et al.
(författare)
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Numerical Investigation and Estimating Correlation of Micromixing Performance of Coaxial Mixers
- 2019
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Ingår i: Industrial and Engineering Chemistry Research. - : American Chemical Society (ACS). - 0888-5885 .- 1520-5045. ; 58:49, s. 22376-22388
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Tidskriftsartikel (refereegranskat)abstract
- In view of the significance, complexity, and difficulty of micromixing in viscous system, coaxial mixers with wide adaptability to viscosity are first combined with micromixing. The effects of feeding position, rotation mode, and impeller type on the micromixing performance of coaxial mixers are investigated numerically with the standard engulfment model and eddy dissipation concept model, and a dimensionless estimating correlation of segregation index Xs is established based on the Buckingham πtheorem. The results show that feeding near the discharge zone of the impeller favors the micromixing and Rushton turbine impeller (RT) is better qualified as the impeller near feeding point compared to six-straight-blade turbine impeller (SBT) and six-pitched (45°)-blade turbine impeller (PBT). At the same specific power consumption, the coaxial mixer has better micromixing performance with PBT + RT as inner impeller than with SBT + RT, and the difference of segregation index resulting from the rotation mode is small. Moreover, the proposed correlation is validated to be suitable for qualitative evaluation of micromixing performance of coaxial mixer consisting of inner impeller combining PBT and RT and outer anchor.
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| 9. |
- Xu, Zilong, et al.
(författare)
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Experimental investigation on solid suspension performance of coaxial mixer in viscous and high solid loading systems
- 2019
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Ingår i: Chemical Engineering Science. - : Elsevier BV. - 0009-2509. ; 208
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Tidskriftsartikel (refereegranskat)abstract
- The coaxial mixers consisting of an inner Rushton turbine or propeller and an outer anchor were combined first with the just off-bottom suspension in viscous and high solid loading systems. In this study, a new method based on RGB brightness analysis was proposed to determine the cloud height, and the measures to promote cloud height were also discussed. In addition, the effects of rotation modes, pumping modes and solid loading on the just-suspension power were investigated. The results showed that the co-rotation coaxial mixers with an up-pumping inner impeller could achieve the just suspension at lower power consumption and were recommended. The combination of anchor and up-pumping propeller was the most energy efficient among the investigated mixers, whereas its cloud height was relatively low. The high off-bottom clearance and the combined inner impeller could promote the cloud height with little power variation, but the enlargement of inner impeller had no obvious effect.
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| 10. |
- Zheng, Xiaoxiao, et al.
(författare)
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Graphene-Oxide-Based Fluoro- and Chromo-Genic Materials and Their Applications
- 2022
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Ingår i: Molecules. - : MDPI AG. - 1431-5157 .- 1420-3049. ; 27:6
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Tidskriftsartikel (refereegranskat)abstract
- Composite materials and their applications constitute a hot field of research nowadays due to the fact that they comprise a combination of the unique properties of each component of which they consist. Very often, they exhibit better performance and properties compared to their combined building blocks. Graphene oxide (GO), as the most widely used derivative of graphene, has attracted widespread attention because of its excellent properties. Abundant oxygen-containing functional groups on GO can provide various reactive sites for chemical modification or functionalization of GO, which in turn can be used to develop novel GO-based composites. This review outlines the most recent advances in the field of novel dyes and pigments encompassing GO as a key ingredient or as an important cofactor. The interactions of graphene with other materials/compounds are highlighted. The special structure and unique properties of GO have a great effect on the performance of fabricated hybrid dyes and pigments by enhancing the color performance of dyes, the anticorrosion properties of pigments, the viscosity and rheology of inks, etc., which further expands the applications of dyes and pigments in dyeing, optical elements, solar-thermal energy storage, sensing, coatings, and microelectronics devices. Finally, challenges in the current development as well as the future prospects of GO-based dyes and pigments are also discussed. This review provides a reference for the further exploration of novel dyes and pigments.
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