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Pseudo-discontinuum model to simulate hard-rock mine pillars

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Underground Space 2023年第4期11卷 81-95页

作者： Erick Ro genes Alessandra dos santos Gomes Marcio Muniz de Farias leandro Lima Rasmussen Faculty of Technology University of BrasiliaDF 70910-900BrasiliaBrazil

In this study,the pseudo-discontinuum modeling technique,called continuum Voronoi block model(CVBM),was applied to repre-sent the behavior of hard-rock pillars from underground mines subjected to high field *** CVBM’s ability to produce numerical results consistent with the observed behavior of pillars is demonstrated through the numerical analysis of a hypothetical case and a back analysis of the Creighton mine *** results show that the model can capture convergence displacements and explicitly show the formation of macro-fractures parallel to excavation walls,intact rock slabs,and V-shaped *** components are characteristics of brittle failure induced by highly stressed ground *** studies presented in this work confirm the CVBM as a convenient tool for the numerical modeling of intact rock pillars excavated in deep underground mines.

关键词： Brittle failure Spalling Bulking Voronoi tessellation

Physical habitat condition as a key tool to maintain freshwater biodiversity in neotropical artificial ponds

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Water Biology and Security 2023年第3期2卷 30-35页

作者： Marden S.Linares Livia B.dos santos Marcos Callisto jean C.santos Universidade Federal de Minas Gerais Instituto de Ciencias BiologicasDepartamento de GeneticaEcologia e EvoluçaoLaboratorio de Ecologia de BentosAv.Antonio Carlos 6627CEP 31270-901PampulhaBelo HorizonteMGBrazil Laboratorio de Macroecologia e Conservaçao da Biodiversidade Departamento de Botanica e EcologiaUniversidade Federal do Mato GrossoAv.Fernando Correa da Costa2367Boa EsperançaCuiabaMato GrossoCEP 78060-900Brazil Programa de Pos-Graduaçao em Ciencias Ambientais Instituto de Ciencias NaturaisHumanas e SociaisUniversidade Federal do Mato GrossoAvenida Alexandre Ferronato1200SinopMTCEP 78550-728Brazil Universidade Federal de Sergipe Departamento de EcologiaCampus Sao Cristovao-Cidade Universitaria Prof.Jose Aloísio de CamposCEP 49100-000Sao CristovaoSergipeBrazil

In areas highly affected by anthropogenic disturbances,artificial(human-made)freshwater ecosystems can provide habitat for maintaining and conserving regional freshwater *** assessed how the physical habitat of artificial ponds affected the structure of benthic macroinvertebrate *** do so,we tested two hypotheses.(1)Physical habitat disturbances are not detrimental to the diversity of nearby artificial ponds,and(2)Physical habitat disturbances do not cause significant shifts in taxonomic *** results rejected both null hypotheses,i.e.,macroinvertebrate diversity metrics correlated significantly and positively with Physical Habitat Integrity index scores,and only sites with high habitat condition scores were significantly associated with sensitive indicator *** results highlight the importance of maintaining physical habitat conditions for sustaining the ecological health of artificial ponds.

关键词： Bioindicators Ecosystem management Lentic ecosystems

Can small-scale altitudinal gradients predict spatial and temporal patterns in tropical forests?

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Journal of Forestry Research 2021年第5期32卷 1854-1865页

作者： Mariana Caroline Moreira Morelli Cléber Rodrigo de Souza jean Daniel Morel Vinícius Andrade Maia Alisson Borges Miranda santos Kaline Fernandes Miranda Rubens Manoel dos santos Forest Sciences Department Federal University of LavrasCampus UniversitárioCx.P.3037LavrasMGCEP 37200-000Brazil Department of Biology Federal University of LavrasCampus UniversitárioLavrasMGCEP 37200-000Brazil

In tropical montane forests,compositional and structural changes are commonly driven by broad-scale altitudinal ***,given the lack of knowledge on small-scale vegetation changes and temporal dynamics,we address the effects of small-scale variations in soil and altitude on tree community structure,temporal dynamics and phylogenetic diversity in a semi-deciduous tropical forest of the Atlantic Forest Domain,southeastern *** 2010 and 2015 we sampled thirty plots of 400 m^(2),set up along an altitudinal gradient between 1000 and 1500 m a.s.I..In each plot,we collected soil samples for chemical and textural *** fitted linear models to test the effects of altitude and soil on community dynamics and phylogenetic *** and soil explained the spatial variation in number of individuals and phylogenetic diversity *** lower to higher altitudes,we found decreasing fertility,increasing tree density and decreasing phylogenetic *** significantly influenced the increases in total biomass(from 240.9 to 255.4 t ha^(-1))and individual biomass(from 0.15 to 0.17 t)recorded in the *** while community temporal dynamics had rates of 1.96%for mortality,1.02%for recruitment,1.61%for biomass loss and 2.81%for biomass gain,none of them were explained by altitude or *** species substitution averaged0.1 in the ***,these results suggest that the small-scale variations in altitude and soil likely determine the conditions and resources that drive community assembly and structure,which are expressed by spatial variations along the altitudinal *** the same time,temporal patterns were not influenced by altitude-related environmental variation,resulting in a similar dynamic behaviour across the gradient,suggesting that broad-scale factors may play a more important role than local ones.

关键词： Fine-scale Semideciduous forests Montane forests Dynamic patterns

Small-scale edaphic heterogeneity as a floristic-structural complexity driver in Seasonally Dry Tropical Forests tree communities

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Journal of Forestry Research 2020年第6期31卷 2347-2357页

作者： Cle´ber Rodrigo de Souza jean Daniel Morel Alisson Borges Miranda santos Wilder Bento da Silva Vinı´cius Andrade Maia Polyanne Aparecida Coelho Vanessa Leite Rezende Rubens Manoel dos santos Forest Sciences Departament Federal University of LavrasCx.P.3037Lavras 37200-000Brazil Biology Department Federal University of LavrasCx.P.3037Lavras 37200-000Brazil

Our work aimed to test the hypothesis that soil microscale heterogeneity act as a community ecological driver,increasing diversity and promoting structural shifts on the Seasonally Dry Tropical Forest(SDTF)tree *** evaluated the relationship between microscale edaphic variations and floristic–structural patterns of tree communities in a SDTF fragment located in the southern end of the Brazilian Caatinga *** and soil data were obtained through 27 sample units of 400 m2(20 m 920 m),within each one we measured and identified at species level all arboreal individuals with Circumference at the Breast Height greater or equal to 10 cm,and also collected the soil *** the data we evaluated soil variation influence on the tree community structural and floristic patterns trough generalized linear *** explained the small-scale structural and floristic variations,contributing significantly to biomass,sprouting and to floristic relationships between sample *** was also observed a possible relation of the result with the Caatinga domain biogeographic history,due the presence of Sedimentary Caatinga species,which are not expected for the study *** plays an important role in driving small-scale complexity and diversity of SDTF,but we also suggest that Caatinga biogeographic events have influence on the high heterogeneity patterns.

关键词： Caatinga domain Edaphic variables Sprouting Sedimentary Caatinga

Gut-microbiome-brain axis:the crosstalk between the vagus nerve,alpha-synuclein and the brain in Parkinson's disease

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Neural Regeneration Research 2023年第12期18卷 2611-2614页

作者： Júlio César Claudino dos santos leandro Freitas Oliveira Felipe Micelli Noleto Camilla Teixeira Pinheiro Gusmão Gerly Anne de Castro Brito Glauce Socorro de Barros Viana Christus University Center-UNICHRISTUS FortalezaCEBrazil Postgraduate Program in Morphofunctional Sciences Federal University of Ceará-UFCFortalezaCEBrazil Universidade Católica de Brasília-UCB BrasíliaDFBrasil Postgraduate Program in Physiology and Pharmacology Department of the Federal University of Ceará-UFC FortalezaCEBrazil Physiology and Pharmacology Department of the Federal University of Ceará-UFC FortalezaCEBrazil

This critical review of the literature shows that there is a close link between the microbiome,the gut,and the brain in Parkinson's *** vagus nerve,the main component of the parasympathetic nervous system,is involved in the regulation of immune response,digestion,heart rate,and control of *** can detect microbiota metabolites through its afferents,transferring this gut information to the central nervous *** and clinical studies have shown the important role played by the gut microbiome and gut-related factors in disease development and progression,as well as treatment *** findings suggest that the gut microbiome may be a valuable target for new therapeutic strategies for Parkinson's *** studies are needed to better understand the underlying biology and how this axis can be modulated for the patient's benefit.

关键词： alpha-synuclein enteric microbiota gastrointestinal tract Parkinson's disease vagus nerve

Fruiting increases total content of flavonoids and antiproliferative effects of Cereus jamacaru D.C. cladodes in sarcoma 180 cells in vitro

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Asian Pacific Journal of Tropical Biomedicine 2019年第2期9卷 66-72页

作者： jean Carlos Vencioneck Dutra Juda Ben-Hur de Oliveira Vanessa Silva dos santos Paula Roberta Costalonga Pereira jean Moises Ferreira Maria do Carmo Pimentel Batitucci Laboratorio de Genetica Vegetal e Toxicologica Departamento de Ciencias BiologicasUniversidade Federal do Espirito Santo Laboratorio de Biologia Molecular e Expressao Genica Departamento de Ciências BiologicasUniversidade Federal de Alagoas

Objective: To evaluate the influence of fruiting phenological stage on total flavonoid content, antioxidant activity, and antiproliferative effects of Cereus jamacaru(C. jamacaru)(mandacaru) cladodes and fruit. Methods: Fruit and cladodes at vegetative and fruiting stage of C. jamacaru were collected. The fruit was dissected and bark, pulp, and seeds were separated. Vegetative and fruiting cladodes, together with bark, pulp, and seeds were used to obtain five hydroalcoholic extracts. The extracts were investigated for total flavonoid content, using AlCl3 colorimetric method, antioxidant activity by 2,2-diphenyl-1-picrylhydrazyl and 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) radical scavenging capacity and Fe^(2+) ion chelating activity, and in vitro antiproliferative effects(sarcoma 180 cells) by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2 H-tetrazolium bromide assay. Results: The extract of C. jamacaru cladodes at the fruiting stage showed higher flavonoid content compared to the other extracts. Seed extracts showed the highest antioxidant activity in 2,2-diphenyl-1-picrylhydrazyl and 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) assays, and the extract of cladodes at vegetative stage showed better antioxidant activity in Fe^(2+) ion chelating activity. The extract of fruiting cladodes promoted higher antiproliferative effects compared to the other extracts. Conclusions: These findings suggest that fruiting increases the content of flavonoids and antiproliferative effects of C. jamacaru cladodes. Data reinforce the potential use of C. jamacaru cladodes and fruits as natural antioxidants and potent anticancer agent.

关键词： Mandacaru Flavonoid content DPPH ABTS Fe^(2+) ion chelating activity MTT assay Sarcoma 180 cells

Application of novel constrained friction processing method to produce fine grained biomedical Mg-Zn-Ca alloy

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Journal of Magnesium and Alloys 2024年第2期12卷 516-529页

作者： Ting Chen Banglong Fu Junjun Shen Uceu F.H.R.Suhuddin Björn Wiese Yuanding Huang Min Wang Jorge F.dos santos jean Pierre Bergmann Benjamin Klusemann Solid State Materials Processing Institute of Material MechanicsHelmholtz-Zentrum HereonMax-Planck-Str.1Geesthacht 21502Germany Functional Magnesium Materials Institute of Metallic BiomaterialsHelmholtz-Zentrum HereonMax-Planck-Str.1Geesthacht 21502Germany Shanghai Key Laboratory of Materials Laser Processing and Modification Shanghai Jiao Tong UniversityDongchuan Road 800Shanghai 200240China Applied Materials and Manufacturing Energy and Environment DivisionPacific Northwest National LaboratoryPO Box 999RichlandWA 99352USA Production Technology Group Technisiche Universität IlmenauGustav-Kirchhoff-Platz 2Ilmenau 98693Germany Institute for Production Technology and Systems Leuphana University of LüneburgUniversitätsallee 1Lüneburg 21335Germany

In order to obtain Mg alloys with fine microstructures and high mechanical performances,a novel friction-based processing method,name as“constrained friction processing(CFP)”,was *** CFP,defect-free Mg-Zn-Ca rods with greatly refined grains and high mechanical properties were *** to the previous as-cast microstructure,the grain size was reduced from more than 1 mm to around 4μm within 3 s by a single process *** compressive yield strength was increased by 350%while the ultimate compressive strength by 53%.According to the established material flow behaviors by“tracer material”,the plastic material was transported by shear *** the base material to the rod,the material experienced three stages,*** by the tool,upward flow with additional tilt,followed by upward *** microstructural evolution was revealed by“stop-action”*** microstructural development at regions adjacent to the rod is mainly controlled by twinning,dynamic recrystallization(DRX)as well as particle stimulated nucleation,while that within the rod is related to DRX combined with grain growth.

关键词： Constrained friction processing Magnesium alloys Microstructure Mechanical properties Grain refinement Plastic deformation

Hydrological variability and long-term floristic-structural modifications in different habitats of a tropical semi-deciduous forest

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Journal of Forestry Research 2022年第3期33卷 801-811页

作者： Alisson Borges Miranda santos Vinicius Andrade Maia Cléber Rodrigo de Souza Natália de Aguiar-Campos Aurélio de Jesus Rodrigues Pais Wilder Bento da Silva Nathalle Cristine Alencar Fagundes jean Daniel Morel Rubens Manoel dos santos Department of Forestry Sciences Federal University of LavrasCampus UniversitárioC.P.3037LavrasBrazil Faculty of Environmental Engineering and Natural Resources Zambeze UniversityChimoioC.P.2400Mozambique Biological Sciences Universidade do Estado de Minas GeraisUnidade ItuiutabaAv.Antônio Carlos 6627Ituiutaba31270-901Brazil Department of Biology Federal University of LavrasUniversity campusC.P.3037Lavras37200-000Brazil

Shifts in hydrological regimes alter river flow rates and flood pulses, decrease environmental heterogeneity and the floristic-structural complexity of associated plant communities. We tested the hypothesis that drought events affect plant community composition and structure at a small-scale within a riparian fragment towards a reduction in floristic-structural complexity. The tree community was sampled in three habitats (wet, transitional and dry) and monitored in seven inventories carried out between 1991 and 2018. Hydrological variations were evaluated through annual rainfalls, river flow rates and water level data. The species richness and the detrended correspondence analysis axes were used to characterise the temporal modifications in floristic composition. Community structure was described in terms of biomass: accumulated, growth of survivors, mortality and recruitment. Generalised linear mixed models were fitted to evaluate the effects of time and environment in community. It was concluded that the climate has become drier in recent years due to declining precipitation that has affected flow rates and water levels. The floristic-structural complexity of the study fragment was maintained during the monitoring period. However, prolonged and extreme drought events displayed the potential to impact floristic-structural patterns.

关键词： Forest dynamics Climate changes Semi-deciduous seasonal forest Temporal change Functioning communities

Synthesis and structure of a praseodymium (Ⅲ) complex with carboxylate ligand：A thermal and spectroscopic study

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Journal of Rare Earths 2018年第10期36卷 1090-1097页

作者： Kátia Veronica Tenório José Augusto Teixeira leandro Moreira de Campos Pinto Flávio Júnior Caires Oswaldo Treu-Filho Fáhio Alencar dos santos Tiago André Denck Colman Alexandre Cuin Cláudio Teodoro de Carvalho Federal University of Grande Dourados CP 364 79804-970 Dourados MS Brazil Institute of Chemistry State University of Sao Paulo 14.801-970 Araraquara SP Brazil Chemistry Institute Federal University of Mato Grosso do Sul 79074-460 Campo Grande MS Brazil Chemistry Department State University of Sao Paulo 17033-360 Bauru SR Brazil Federal University of Juiz de Fore 36036-330 Juiz de Fora MG Brazil

One Pr（Ⅲ） lanthanide ion complex was initially synthesized and characterized by TGA-DSC in air atmosphere, as well as characterized by CHN elemental analysis, defining the stoichiometric ratio as Pr（DMBz）3. The gaseous products evolved during the thermal decomposition were also monitored in N2 atmosphere employing TGA/FT-IR system. A crystal structure is obtained by state-of-the-art powder X-rays diffraction methods measured in conventional laboratory equipment and refined by the Rietveld method, which defined it as a monoclinic system of the space group P21/C with a polymeric crystal structure, [Pr（DMBZ）3]n. FT-IR theoretical spectrum and time-dependent density functional theory（TD-DFT） were calculated from TGA-DSC and crystalline system data. The experimental and theoretical FT-IR spectra present a high correlation degree when the main stretching bands are compared, while the energy transfer（HOMO - LUMO） in their neighborhoods suggests the main contributions of the light-emitting states.

关键词： Complex Thermal analysis Powder diffraction state-of-art Polymeric structure Theoretical calculation Rare earths