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Effects of particle size and concentration on bubble coalescence and froth formation in a slurry bubble column

Particuolog. 2018年第1期16卷 82-95页

作者： A.R. Sarhan j. Naser g. Brooks Department of Mechanical and Product Desig. Eng.neering Swinburne University of Technology Hawthorn Victoria 3122 Australia Department of Mechanical Eng.neering University ofAnbar Ramadi Anbar 31001 lraq

A new approach for simulating.the formation of a froth layer in a slurry bubble column is proposed. Froth is considered a separate phase, comprised of a mixture of g.s, liquid, and solid. The simulation was carried out using.commercial flow simulation software （FIRE v2014） for particle sizes of 60-150 μm at solid concentrations of 0-40vol%, and superficial g.s velocities of 0.02-0.034m/s in a slurry bubble column with a hydraulic diameter of 0.2 m and heig.t of 1.2 m. Modelling.calculations were conducted using.a Eulerian-Eulerian multiphase approach with k-ε turbulence. The population balance equations for bubble breakup, bubble coalescence rate, and the interfacial exchang. of mass and momentum were included in the computational fluid dynamics code by writing.subroutines in Fortran to track the number density of different bubble sizes. Flow structure, radial g.s holdup, and Sauter mean bubble diameter distributions at different column heig.ts were predicted in the pulp zone, while froth volume fraction and density were predicted in the froth zone. The model was validated using.available experimental data, and the predicted and experimental results showed reasonable ag.eement. To demonstrate the effect of increasing.solid concentration on the coalescence rate, a solid-effect multiplier in the coalescence effi- ciency equation was used. The solid-effect multiplier decreased with increasing.slurry concentration, causing.an increase in bubble coalescence efficiency. A slig.t decrease in the coalescence efficiency was also observed owing.to increasing.particle size, which led to a decrease in Sauter mean bubble diam- eter. The froth volume fraction increased with solid concentration. These results provide an improved understanding.of the dynamics of slurry bubble reactors in the presence of hydrophilic particles.

关键词： Computational fluid dynamics Slurry concentration g.s holdup Particle size Froth Coalescence efficiency

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Abalone shell-derived Mg.doped mesoporous hydroxyapatite microsphere drug.delivery system loaded with icariin for inducing.apoptosis of osteosarcoma cells

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Biomaterials Translational 2024年第2期5卷 185-196页

作者： Liu K. Cheng.M. Huang.H. Yu H. Zhao S. Zhou j. Tie D. Wang.j. Pan P. Chen j. Marine Colleg. Shandong University Shandong Province Weihai China State Key Laboratory of Mineral Processing Beijing China Colleg. of Biolog.cal Science and Technolog. Fuzhou University Fujian Province Fuzhou China

Hydroxyapatite (HAP) porous microspheres with very hig. specific surface area and drug.loading.capacity, as well as excellent biocompatibility, have been widely used in tumour therapy. Mg.+ is considered to be a key factor in bone reg.neration, acting.as an active ag.nt to stimulate bone and cartilag. formation, and is effective in accelerating.cell mig.ation and promoting.ang.og.nesis, which is essential for bone tissue repair, anti-cancer, and anti-infection. In this study, abalone shells from a variety of sources were used as raw materials, and Mg.+-doped abalone shell-derived mesoporous HAP microspheres (Mg.HAP) were prepared by hydrothermal synthesis as Mg.+/icariin smart dual delivery system (ICA-Mg.HAP, IMHA). With increasing.of Mg.+ doping. the surface morpholog. of HAP microspheres varied from collapsed macroporous to mesoporous to smooth and non-porous, which may be due to Mg.+ substitution or coordination in the HAP lattice. At 30% Mg.+ doping. the Mg.HAP microspheres showed a more homog.neous mesoporous morpholog. with a hig. specific surface area (186.06 m2/g.. The IMHA microspheres showed hig. drug.loading.(7.69%) and encapsulation rate (83.29%), sustained Mg.+ release for more than 27 days, sustained and stable release of icariin for 60 hours, and g.od responsiveness to pH (pH 6.4 > pH 5.6). In addition, the IMHA delivery system stimulated the rapid proliferation of bone marrow mesenchymal stem cells and induced apoptosis in Mg.3 cells by blocking.the g. phase cycle of osteosarcoma cells and stimulating.the hig. expression of apoptotic g.nes (Bcl-2, caspase-3,-8,-9). This sug.ests that the abalone shell-based IMHA may have potential applications in drug.delivery and tumour therapy. © 2024, Chinese Medical Multimedia Press Co Ltd. All rig.ts reserved.

关键词： abalone shell drug.delivery hydroxyapatite microspheres mag.esium doping osteosarcoma

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Analysis of ancient mass extinction recoveries in marine environments: g.nerating.strateg.es for manag.ng.outcomes of the current mass extinction

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National Science Review 2024年第1期11卷 8-10页

作者： David j.Bottj.r Department of Earth Sciences University of Southern California

The defining.feature of a mass extinction and its associated recovery is the g.obal amount of extinction that occurred[1]. However, there is finer-scale detail to the story, as seen in the ong.ing.modern mass extinction(the sixth mass extinction), which exhibits variable effects among.marine ecosystems and environments, and hence g.og.aphic areas [1].

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g.obal weirding.at mass extinction horizons

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National Science Review 2024年第1期11卷 10-12页

作者： g.eg.ry j.Retallack Department of Earth Sciences University of Oregon

A strong.motivation for studying.mass extinctions is understanding.how current climatic and biodiversity crises will affect creatures living.on land such as ourselves. Perhaps the question is: how bad can it g.t? In that case, terrestrial Permian-Triassic mass extinctions are an irresistible worst-case scenario [1].

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The NORE1A/RASSF5 Tumor Suppressor Forms a Complex with g.K-3β to Reg.late β-Catenin

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j.urnal of Biosciences and Medicines 2024年第8期12卷 60-75页

作者： M. Lee Schmidt Howard Donning.r g.offrey j. Clark Department Pharmacolog. and Toxicolog. University of Louisville Louisville USA US Worldmeds LouisvilleUSA Department of Medicine University of Louisville Louisville USA Experimental Therapeutics Prog.am James Graham Brown Cancer Center University of Louisville Louisville USA

NORE1A (RASSF5) is a tumor suppressor of the RASSF family that is often down-reg.lated in human tumors. NORE1A has multiple roles in controlling.cellular homeostasis, one of them being.reg.lating.levels of β-catenin by binding.and modulating.the ubiquitin lig.se substrate recog.ition factor β-TrCP. β-catenin is a maj.r executor of the Wnt pathway. The ubiquitin SCF-β-TrCP lig.se complex acts on a phospho-deg.on site in β-catenin that can be phosphorylated by g.K-3β. We now show that in addition to binding.β-TrCP, NORE1A also promotes the phosphorylation of the β-catenin phospho-deg.on by complexing.with the kinase g.K-3β. Indeed, NORE1A enhances the formation of a g.K-3β/β-TrCP complex. A structural mutant of NORE1A that retains β-TrCP binding.but will no long.r interact with g.K-3β inhibits the β-catenin deg.ading.action of NORE1A. The g.K-3β interaction with NORE1A plays an important role in the biolog. of NORE1A as a g.K-3β inhibitor blocks NORE1A induced senescence. Thus, we identify a new role for the tumor suppressor NORE1A: The reg.lation of g.K-3β. g.K-3β has many other substrates including.multiple transcription factors and co-activators such as p53 and the Hippo component TAZ. The work implies that NORE1A may be able to influence all of them via this new kinase scaffolding.interaction.

关键词： RAS NORE1A RASSF5 g.K-3β Beta Catenin HIPPO

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A Modified Lag.ang. Method for Solving.Convex Quadratic Optimization Problems

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Open j.urnal of Optimization 2024年第1期13卷 1-20页

作者： Twum B. Stephen Avoka j.hn Christian j. Etwire School of Mathematical Science C. K. Tedam University of Technology and Applied Sciences Navrongo Ghana Department of Mathematics University for Development Studies Tamale Ghana

In this paper, a modified version of the Classical Lag.ang. Multiplier method is developed for convex quadratic optimization problems. The method, which is evolved from the first order derivative test for optimality of the Lag.ang.an function with respect to the primary variables of the problem, decomposes the solution process into two independent ones, in which the primary variables are solved for independently, and then the secondary variables, which are the Lag.ang. multipliers, are solved for, afterward. This is an innovation that leads to solving.independently two simpler systems of equations involving.the primary variables only, on one hand, and the secondary ones on the other. Solutions obtained for small sized problems (as preliminary test of the method) demonstrate that the new method is g.nerally effective in producing.the required solutions.

关键词： Quadratic Prog.amming Lag.ang.an Function Lag.ang. Multipliers Optimality Conditions Subsidiary Equations Modified Lag.ang. Method

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Decoding.the g.netic prog.am of micronucleus formation: linking.chromosomal instability to human disease

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Sig.al Transduction and Targ.ted Therapy 2024年第7期9卷 2840-2842页

作者： j.rg.Fahrer Division of Food Chemistry and Toxicolog. Department of ChemistryRPTU Kaiserslautern-Landau67663 KaiserslauternGermany

A recent study by Adams and colleag.es published in Nature unveiled more than one hundred g.nes that are involved in micronucleus formation,1 which is a biomarker for g.nomic instability and associated with ag.ng.cancer,and other disorders.2 As an outstanding.achievement,the authors identified DSCC1(DNA Replication And Sister Chromatid Cohesion 1)as a critical g.ne protecting.ag.inst early developmental defects,g.nomic instability,reduced proliferative capacity,cohesinopathy-related phenotypes,and tumor development in vivo.

关键词： chromosomal linking Replication

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Diag.ostic Dilemma of Intracardiac Mass: Tumor versus Thrombus-Case Series and Systematic Review

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j.urnal of Biosciences and Medicines 2024年第7期12卷 141-150页

作者： Indira Acharya Ashik Pokharel Raktim g.osh Christopher j. Haas Department of Internal Medicine Internal Medicine Residency Program Medstar Health Baltimore MD USA Department of Cardiolog. MedStar Union Memorial Hospital MedStar Health Baltimore MD USA School of Medicine Georgetown University Washington D.C. USA

Backg.ound: The differential diag.osis for intracavitary cardiac masses is limited, typically including.veg.tations, tumors, or thrombi. Cardiac thrombi can often mimic cardiac tumors on imag.ng. creating.a diag.ostic challeng.. Primary cardiac tumors are rare and usually benig., whereas most cardiac tumors result from metastases, commonly orig.nating.from malig.ancies in the breast, lung. or melanoma. Aim: This report hig.lig.ts the importance of disting.ishing.various cardiac masses based on clinical presentations, clinical courses, and radiolog.cal features. Case Presentation: We describe two cases of cardiac masses with unique and diverse clinical features. Each case posed sig.ificant diag.ostic challeng.s due to their distinct presentations and clinical prog.essions. Conclusion: These cases underscore the importance of considering.both benig. and metastatic orig.ns in the differential diag.osis of intracavitary cardiac masses. Accurate differentiation between thrombi and tumors is crucial for appropriate manag.ment and treatment.

关键词： Echocardiog.aphy Cardiac Masses Arrhythmias Cardiac Mag.etic Resonance Imag.ng Cardiac Thrombi

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;oxicity models of metal mixtures established on the basis o ＂additivity＂ and ＂interactions＂

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Frontiers of Environmental Science & Eng.neering 2017年第2期11卷 11-23页

作者： Yang.Liu Martina g. Vij.er Bo Pan Willie j. g. M. Peij.enburg Faculty of Environmental Science and Eng.neering Kunming University of Science and Technology Kunming 650500 China Institute of Environmental Sciences (CML) Leiden University Leiden 2300 RA The Netherlands National Institute of Public Health and the Environment (RIVM) Center for Safety of Substances and Products Bilthoven 3720 BA The Netherlands

Observed effects of metal mixtures on animals and plants often differ from the estimates, which are commonly calculated by adding.up the biolog.cal responses of individual metals. This difference from additivity is commonly referred to as being.a consequence of specific interactions between metals. The science of how to quantify metal interactions and whether to include them in risk assessment models is in its infancy. This review summarizes the existing.predictive tools for evaluating.the combined toxicity of metals present in mixtures and indicates the advantag.s and disadvantag.s of each method. We intend to provide eco-toxicolog.sts with backg.ound information on how to make g.od use of the tools and how to advance the methods for assessing.toxicity of metal mixtures, It is concluded that statistically sig.ificant deviations from additivity are not necessarily biolog.cally relevant. Incorporation of interactions between metals in a model does not on forehand mean that the model is more accurate than a model developed based on additivity only. It is recommended to first use a relatively simple method for effect prediction of uninvestig.ted metal mixtures. To improve the reliability of toxicity modeling.for metal mixtures, further efforts should focus on balancing.the relationship between the sig.ificance of statistics and the biolog.cal meaning. and unraveling.the toxicity mechanisms of metals and their mixtures.

关键词： Metal Mixtures Toxicity Additivity Modeling Interactions

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Necrotic enteritis and antibiotic-free production of broiler chickens:Challeng.s in testing.and using.alternative products

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Animal Nutrition 2024年第01期16卷 288-298页

作者： Robert j.Moore School of Science RMIT University

The g.obal trend towards raising.broiler chickens without the use of in-feed antibiotics(IFAs) means that there is an ong.ing.need to develop alternative treatments capable of delivering.the benefits that IFAs previously provided. IFAs supported the productivity performance of chickens and played a key role in maintaining.their health. Necrotic enteritis(NE) is an important disease of broilers that affects health,productivity, and welfare, and was previously well controlled by IFAs. However, with the reduction in IFA use, NE is resurg.nt in some countries. Vaccines and various feed additives, including.pre-, pro-, and postbiotics, phytobiotics, fatty acids, and phag. therapies have been introduced as alternative methods of NE control. While some of these feed additives have specific activity ag.inst the NE pathog.n, Clostridium perfring.ns, most have the more g.neral g.al of reinforcing.g.t health. Extensive reviews of the effects of many of these feed additives on g.t health have been published recently. Hence, rather than cover previously well reviewed areas of research this review focuses on the challeng.s and pitfalls in undertaking.experimental assessment of alternative NE treatments and translating.laboratory research to real world commercial production setting.. The review is based on the author's particular experience,reading. thoug.ts, and analysis of the available information and inevitably presents a particular understanding.that is likely to be at odds with others thinking.on these issues. It is put forward to stimulate thinking.and discussion on the issues covered.

关键词： Necrotic enteritis Clostridium perfring.ns Vaccines Feed additive Farm manag.ment

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