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A coarse-grained bonded particle model for large-scale rock simulation

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Rock Mechanics Bulletin

Rock Mechanics Bulletin 2024年第4期3卷 58-69页

作者： Chengshun Shang Liping Li Kaiwei Chu Zongqing Zhou Guillermo casas Wenfeng Tu Yuxue Chen Shangqu Sun School of Qilu Transportation Shandong University250061JinanChina International Center for Numerical Methods in Engineering(CIMNE) 08034BarcelonaSpain Universitat politecnica de Catalunya(UpC) 08034BarcelonaSpain Geotechnical and Structural Engineering Research Center Shandong University250061JinanChina College of Civil Engineering and Architecture Shandong University of Science And Technology266590QingdaoChina

For solving the computationally intensive problem encountered by the discrete element method(DEM)in simulating large-scale engineering problems,it is essential to establish a numerical model that can effectively simulate large-scale *** this study,the coarse-graining effect of a linear-Mindlin with bonding model was studied in the unconfined compression strength(UCS)and Brazilian tensile strength(BTS)*** found that the main reason for the coarse-graining effect of the BTS tests is that the type I fracture toughness is positively correlated with the size of the *** on the results analysis and fracture mechanics,the coarse-grained(CG)modeling theory was combined with a bonded particle model(BpM)for the first time and a coarse-grained bonded particle model(CG-BpM)was developed,which can be effectively used to model the tensile strength of large-scale rocks with different particle *** excavation damage zone(EDZ)in an underground research laboratory(URL)was selected as an application case,which shows that the coarse-grained bonding model presented in this paper is more accurate and reliable than the traditional one in large-scale rock simulation,at least in the scenario where tensile failure is dominant.

关键词： Numerical simulation Discrete element method(DEM) Coarse-grained bonded particle model(CGBpM) Large-scale rock

中低收入国家的慢性病:背景、决定因素与卫生政策

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中国卫生政策研究 2013年第10期6卷 12-20页

作者： Miranda j j Kinra S casas j.p.Davey Smith G Ebrahim S 伦敦卫生与热带病医学院布里斯托大学

近年来,中低收入国家慢性病不断上升的趋势及其产生的影响受到广泛关注,但有关这种上升趋势的解释和说明大多基于高收入国家的慢性病发展史,但其所经历的发展历程与中低收入国家并不完全相同。本文对这些差异进行评价,以更好地理解中低... 详细信息

近年来,中低收入国家慢性病不断上升的趋势及其产生的影响受到广泛关注,但有关这种上升趋势的解释和说明大多基于高收入国家的慢性病发展史,但其所经历的发展历程与中低收入国家并不完全相同。本文对这些差异进行评价,以更好地理解中低收入国家慢性病的流行趋势,并对慢性病决定因素的相关理论加以讨论,为慢性病的防控提供循证支持。此外,本文将慢性病防控政策看作是降低人口患病风险和个体易感性的重要干预手段,并讨论了中低收入国家需要开展的相关政策研究。在此基础上进一步强调了加强初级卫生保健改革的必要性,并将其作为降低慢性病流行趋势的一项重要政策。

关键词：发展中国家健康转变非传染性疾病公共卫生危险因素

Selective butyric acid production from CO_(2)and its upgrade to butanol in microbial electrosynthesis cells

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Environmental Science and Ecotechnology 2024年第1期17卷 119-127页

作者： Meritxell Romans-casas Laura Feliu-paradeda Michele Tedesco Hubertus V.M.Hamelers Lluis Bañeras M.Dolors Balaguer Sebastiàpuig paolo Dessì Institute of the Environment University of Girona.Campus MontiliviCarrer Maria Aurélia Capmany 69E-17003GironaSpain Molecular Microbial Ecology Group Institute of Aquatic EcologyUniversity of GironaMaria Aurelia Capmany 4017003GironaSpain Wetsus European Centre of Excellence for Sustainable Water TechnologyOostergoweg 98911MALeeuwardenthe Netherlands

Microbial electrosynthesis(MES)is a promising carbon utilization technology,but the low-value products(i.e.,acetate or methane)and the high electric power demand hinder its industrial *** this study,electrically efficient MES cells with a low ohmic resistance of 15.7 mU m^(2)were operated galvanostatically in fed-batch mode,alternating periods of high CO_(2)and H2 *** promoted acetic acid and ethanol production,ultimately triggering selective(78%on a carbon basis)butyric acid production via chain *** average production rate of 14.5 g m^(-2)d^(-1)was obtained at an applied current of 1.0 or 1.5 mA cm^(-2),being Megasphaera *** key chain elongating *** a second cell with the catholyte containing the enriched community resulted in butyric acid production at the same rate as the previous cell,but the lag phase was reduced by 82%.Furthermore,interrupting the CO_(2)feeding and setting a constant pH2 of 1.7e1.8 atm in the cathode compartment triggered solventogenic butanol production at a pH below *** efficient cell design resulted in average cell voltages of 2.6e2.8 V and a remarkably low electric energy requirement of 34.6 kWhel kg1 of butyric acid produced,despite coulombic efficiencies being restricted to 45%due to the cross-over of O_(2)and H2 through the *** conclusion,this study revealed the optimal operating conditions to achieve energy-efficient butyric acid production from CO_(2)and suggested a strategy to further upgrade it to valuable butanol.

关键词： Biocathode Bioelectrochemical system Chain elongation Hydrogen partial pressure Megasphaera

Electrospun pLLA Membranes for Caffeine Delivery: Diffusional Approach

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journal of Biomedical Science and Engineering 2017年第12期10卷 563-574页

作者： Ana paula S. Immich josé Antonio Tornero Francesc Cano casas Manuel j. Lis Arias Institut d’Investigació Tèxtil i Cooperació Industrial de Terrassa Universitat Politècnica de Catalunya Terrassa Spain Chemical Engineering Department Universitat Politècnica de Catalunya Terrassa Spain

One of the great advantages of electrospun fibers is the large tridimensional area produced, capable of storing any type of material. The aim of our investigation is to study the electrospinning technique to produce polymer membranes for drug delivery applications, given their large surface area and ability to transport a bioactive compound. A mathematical modeling of the delivery system kinetics was also studied to find the mechanism that controls the releasing process. Results showed that electrospinning could provide regular and smooth membranes suitable for drug delivery processes. The mathematical modeling also proved that thicker pLLA membranes exhibited a Fickian diffusion behavior during the drug transport, presenting better control in drug delivery processes.

关键词： Diffusion polymer Nano Escale Kinetics

Degradable magnesium-hydroxyapatite interpenetrating phase composites processed by current assisted metal infiltration in additive-manufactured porous preforms

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journal of Magnesium and Alloys 2022年第12期10卷 3641-3656页

作者： Mariano casas-Luna Edgar B.Montufar Norbert Hort Sebastian Díaz-de-la-Torre joséClaudio Méndez-García Lucie Vištejnová Adam Brínek AlešDanhel Karel Dvorak jozef Kaiser Ladislav Celko Central European Institute of Technology Brno University of TechnologyPurkynova 123Brno 61200Czech Republic Institute of Metallic Biomaterials Helmholtz-Zentrum HereonMax-Planck-Straße 1Geesthacht 21502Germany Institute of product and process Innovation Leuphana University LüneburgUniversitätsallee 1Lüneburg 21335Germany Centro de Investigación e Innovación Tecnológica Instituto Politécnico NacionalCerrada de Cecati s/nMexico City 02250Mexico Biomedical Center Faculty of Medicine in PilsenCharles UniversityAlej Svobody 1655/76Plzen 32300Czech Republic Institute of Biophysics of the Czech Academy of Sciences Královopolská135Brno 61265Czech Republic Faculty of Civil Engineering Brno University of TechnologyPurkynova 139Brno 61200Czech Republic

This work explores ceramic additive manufacturing in combination with liquid metal infiltration for the production of degradable interpenetrating phase magnesium/hydroxyapatite(Mg/HA) composites. Material extrusion additive manufacturing was used to produce stoichiometric,and calcium deficient HA preforms with a well-controlled open pore network, allowing the customization of the topological relationship of the composite. pure Mg and two different Mg alloys were used to infiltrate the preforms by means of an advanced liquid infiltration method inspired by spark plasma sintering, using a novel die design to avoid the structural collapse of the preform. Complete infiltration was achieved in 8 min, including the time for the Mg melting. The short processing time enabled to restrict the decomposition of HA due to the reducing capacity of liquid Mg. The pure Mg-base composites showed compressive yield strength above pure Mg in cast state. Mg alloy-based composites did not show higher strength than the bare alloys due to grain coarsening, but showed similar mechanical properties than other Mg/HA composites that have significantly higher fraction of metallic phase. The composites showed faster degradation rate under simulated body conditions than the bare metallic component due to the formation of galvanic pairs at microstructural level. Mg dissolved preferentially over HA leaving behind a scaffold after a prolonged degradation period. In turn, the fast production of soluble degradation products caused cell metabolic changes after 24 h of culture with not-diluted material extracts. The topological optimization and reduction of the degradation rate are the topics for future research.

关键词： Interpenetrating phase composite Biodegradable metal Topological relationship Direct ink writing Metal infiltration Computed aided design

Non-antibiotic feed additives in diets for pigs:A review

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Animal Nutrition 2018年第2期4卷 113-125页

作者： Yanhong Liu Charmaine D.Espinosa jerubella j.Abelilla Gloria A.casas L.Vanessa Lagos Su A.Lee Woong B.Kwon john K.Mathai Diego M.D.L.Navarro Neil W.jaworski Hans H.Stein Department of Animal Science University of California Department of Animal Sciences University of Illinois Department of Animal production College of Animal and Veterinary SciencesUniversity of Colombia Trouw Nutrition

A number of feed additives are marketed to assist in boosting the pigs' immune system, regulate gut microbiota, and reduce negative impacts of weaning and other environmental *** most commonly used feed additives include acidifiers, zinc and copper, prebiotics, direct-fed microbials, yeast products, nucleotides, and plant *** of pharmacological levels of zinc and copper, certain acidifiers, and several plant extracts have been reported to result in improved pig performance or improved immune function of *** is also possible that use of prebiotics, direct-fed microbials, yeast,and nucleotides may have positive impacts on pig performance, but results have been less consistent and there is a need for more research in this area.

关键词： Acidifiers Direct-fed microbials Minerals plant extracts prebiotics pigs

Naringenin prevents experimental liver fibrosis by blocking TGFβ-Smad3 and jNK-Smad3 pathways

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World journal of Gastroenterology 2017年第24期23卷 4354-4368页

作者： Erika Hernández-Aquino Natanael Zarco Sael casas-Grajales Erika Ramos-Tovar Rosa E Flores-Beltrán jonathan Arauz Mineko Shibayama Liliana Favari Víctor Tsutsumi josé Segovia pablo Muriel Laboratory of Experimental Hepatology Department of PharmacologyCinvestav-IPNApartado Postal 14-740Mexico City Department of physiology Biophysics and NeurosciencesCinvestav-IPNApartado Postal 14-740Mexico City Department of pharmacology School of MedicineAutonomous University of Baja CaliforniaMexicaliApartado Postal 21100 Department of Infectomics and Molecular pathogenesis Cinvestav-IPNApartado Postal 14-740Mexico City

To study the molecular mechanisms involved in the hepatoprotective effects of naringenin (NAR) on carbon tetrachloride (CCl4)-induced liver fibrosis. METHODSThirty-two male Wistar rats (120-150 g) were randomly divided into four groups: (1) a control group (n = 8) that received 0.7% carboxy methyl-cellulose (NAR vehicle) 1 mL/daily p.o.; (2) a CCl4 group (n = 8) that received 400 mg of CCl4/kg body weight i.p. 3 times a week for 8 wk; (3) a CCl4 + NAR (n = 8) group that received 400 mg of CCl4/kg body weight i.p. 3 times a week for 8 wk and 100 mg of NAR/kg body weight daily for 8 wk p.o.; and (4) an NAR group (n = 8) that received 100 mg of NAR/kg body weight daily for 8 wk p.o. After the experimental period, animals were sacrificed under ketamine and xylazine anesthesia. Liver damage markers such as alanine aminotransferase (ALT), alkaline phosphatase (Ap), γ-glutamyl transpeptidase (γ-GTp), reduced glutathione (GSH), glycogen content, lipid peroxidation (LpO) and collagen content were measured. The enzymatic activity of glutathione peroxidase (Gpx) was assessed. Liver histopathology was performed utilizing Masson’s trichrome and hematoxylin-eosin stains. Zymography assays for MMp-9 and MMp-2 were carried out. Hepatic TGF-β, α-SMA, CTGF, Col-I, MMp-13, NF-κB, IL-1, IL-10, Smad7, Smad3, pSmad3 and pjNK proteins were detected via western blot. RESULTSNAR administration prevented increases in ALT, Ap, γ-GTp, and Gpx enzymatic activity; depletion of GSH and glycogen; and increases in LpO and collagen produced by chronic CCl4 intoxication (p pathology showed a decrease in collagen deposition when rats received NAR in addition to CCl4. Although zymography assays showed that CCl4 produced an increase in MMp-9 and MMp-2 gelatinase activity; interestingly, NAR administration was associated with normal MMp-9 and MMp-2 activity (p < 0.05). The anti-inflammatory, antine

关键词： Fibrosis Transforming growth factor-β Naringenin pSmad3 Smad3 jNK Nuclear factor kappa Carbon tetrachloride

西班牙比利牛斯山脉东部巴尔德里韦斯前卡拉道克统岩石中层控砷-金的矿化作用

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国外火山地质 1988年第2期 81-89页

作者： C.Avora j.M.casas 胡青

与火山岩伴生的前卡拉道克统的下部具有浸染状和透镜状的含金和 Bi—Ag—Cu—pb—Zn—W矿物的砷黄铁矿和黄铁矿。这些金属矿物与相同矿物成分的脉和次生团块伴生。浸染状矿化产出在几厘米厚含透镜体的砂屑泥质岩的韵律层和白云岩中。产... 详细信息

与火山岩伴生的前卡拉道克统的下部具有浸染状和透镜状的含金和 Bi—Ag—Cu—pb—Zn—W矿物的砷黄铁矿和黄铁矿。这些金属矿物与相同矿物成分的脉和次生团块伴生。浸染状矿化产出在几厘米厚含透镜体的砂屑泥质岩的韵律层和白云岩中。产在韵律层和白云岩中的次生矿体是由后成变形相引起先前的浸染状和透镜状矿化重新富集而形成的。

关键词：白云岩韵律层碳酸盐岩地层铁矿物黄铁矿矿脉群卡拉无机化矿化矿物成份矿物成分喷出岩火成岩火山岩岩石浸染状石英脉碳酸盐层砷黄铁矿硫化矿物毒砂法国中央地块韦斯矿化作用巴尔南欧西班牙

Extraction of Carotenoids and Fatty Acids from Microalgae Using Supercritical Technology

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American journal of Analytical Chemistry 2012年第12期3卷 877-883页

作者： Lourdes casas Cardoso Casimiro Mantell Serrano Miguel Rodríguez Rodríguez Enrique j. Martínez de la Ossa Luis M. Lubián Department of Chemical Engineering and Food Technology Faculty of Science University of Cadiz International Agri-Food Campus of Excellence Cadiz Spain Institute for Marine Science of Andalucia (CSIC) Cadiz Spain

The work described here is based on a comparative study of carotenoids and fatty acids extracted from Synechococcus sp. with (1) pure supercritical CO2, (2) CO2 with 5% (v/v) ethanol as cosolvent and (3) ultrasound-assisted extraction using N, N-dimethylformamide (DMF). The effects of extraction conditions on supercritical CO2 extraction with and within cosolvent were analyzed at different temperatures (40℃, 50℃ and 60℃) and pressures (200, 300 and 400 bars). SFE with CO2 proved to be the most selective method for the extraction of β-carotene, but under these conditions the contents of zeaxanthin and fatty acids were only comparable to or lower than those obtained with techniques that use SFE cosolvent. The SFE technique with CO2 and ethanol simultaneously extracted β-carotene and zeaxanthin and not only increased the concentrations of fatty acids obtained, but also helped to remove fatty acids (palmitoleic and linolenic acid) that were not obtained with pure CO2. Comparison of the supercritical technology with the ultrasound-assisted extraction (UAE) shows that the former technique is the most appropriate due to the fact that ethanol is generally regarded as a safe solvent in comparison to DMF.

关键词： Carotenoids Fatty Acids Synechococcus sp. Supercritical Technology Ultrasound-Assisted Extraction