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The ecological scale mediates whether trees experience drought legacies in radial growth

Forest Ecosystems 2023年第3期10卷 298-306页

作者： Héctor Hernández-Alonso Jaime Madrigal-González Fernando Silla Area of Ecology Faculty of BiologyUniversidad de SalamancaE-37007SalamancaSpain iuFOR-EiFAB Campus de SoriaUniversidad de ValladolidE-42004SoriaSpain

The impact of lag effects produced by disturbances on primary production has been a major concern among ecologists during the last *** and extreme climatic events are imposing drastic reductions in radial growth of trees as evidenced in tree-rings series Dendrochronological samples are obtained at tree level but analyzed at an aggregated scale(i.e.,mean chronologies),although aggregating tree-ring chronology on a regional scale may reduce the possibility of studying the variability of individual tree response to drought,by amplifying the average population ***,we conducted experimental research in which 370 trees of 5 species were analyzed to assess the potential statistical and scaling issues that may occur when using regressionbased methods to analyze ecosystem responses to *** legacy effects were quantified using individual and aggregated ***,lag effects were validated using confidence and prediction intervals to identify values falling outside the certainty of the climate-growth model Individual scale legacy effects contrasted with confidence intervals were commonly distributed across species but were scarce when compared with prediction *** analysis of aggregated scale legacies detected significant growth reductions when validated using prediction intervals;however,individual scale legacy lag effects were not *** finding directly contrasts the results obtained when using an aggregated *** results provide empirical evidence on how aggregating ecological data to infer processes that emerge from an individual scale can lead to distorted *** therefore encourage the use of individual based statistical and ecological procedures to analyze tree rings as a means of further understanding the ecosystem responses to disturbances.

关键词： Legacy effects Drought disturbances Tree growth Tree-ring width Dendrochronology Individual scale Mountainous forests

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Metabolic Cycles: Effect of a Simultaneous Input and Output of Two Substrates

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Journal of Biomedical Science and Engineering 2016年第13期9卷 624-637页

作者： Antonio Sillero víctor García-Herrero Departamento de Bioquí mica Facultad de Medicina Instituto de Investigaciones Biomédicas Alberto Sols (UAM/CSIC) Arzobispo Morcillo Madrid Spain

The metabolic cycle firstly considered here is composed of a unique initial substrate, six enzymes, and five empty boxes to accommodate the substrates derived from the transformation of the initial substrate. This cycle was considered as a pre-Closed Metabolic Cycle (CMC). Using this model, the influence of changing the kinetic constant values of any enzyme on the substrate concentration was explored. This model was transformed into an open metabolic cycle (OMC) by the input and output of two metabolites catalyzed by two external enzymes. In this case, the relative rates of input and output of metabolites were also examined;it can be concluded that the OMC cycles form delicate and fragile structures which can be theoretically disrupted, making them metabolically unfeasible.

关键词： Metabolic Cycles Metabolic Regulation Kinetic Constants Differential Equations Metabolites: Input and Output

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Closed and Open Metabolic Cycles: Transition Time

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Journal of Biomedical Science and Engineering 2016年第2期9卷 127-140页

作者： Antonio Sillero víctor García-Herrero Departamento de Bioquímica Facultad de Medicina Instituto de Investigaciones Biomédicas Alberto Sols UAM/CSIC Madrid Spain

A metabolic cycle can be viewed as a central core and its branches. The central core is here firstly considered as a pre-closed metabolic cycle (CMC), with a unique first substrate, but with no input or output of other components. By contrast, the metabolic cycles in nature are open metabolic cycles (OMC) with output and input of external substrates (through “metabolic branches”), modulating continuously the enzyme activities and the total concentration of their substrates thorough complex regulatory phenomena. In this work, the transition from a Closed to an Open metabolic cycle has been simulated by a consecutive entry and exit of two components through the catalytic action of two enzymes. It is known that after any alteration of the initial conditions, the cycles need a time to reach new equilibrium. We have measured the changes of transition time (T.T.) values in 81 models of CMC differing in Km or vmax values. In general, the T.T. tends to be shorter in cycles with preponderant lower Km and higher vmax values. Further, Mathematica refinement for the estimation of transition time from the data previously calculated can be obtained with the use of the command Interpolating Function.

关键词： Metabolic Cycles Equilibration Times Kinetic Constants Differential Equations Mathematica

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Copper and Cyanide Recovery in Cyanidation Effluents

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Advances in Chemical Engineering and Science 2011年第4期1卷 191-197页

作者： José R. parga Jesús L. valenzuela Héctor Moreno Jaime E. pérez 不详

Cyanidation is the main process for gold and silver recovery from its ores. In this study, a process is proposed to recover copper and cyanide from barren solutions from the Merrill-Crowe cementation process with zinc dust. This technology is based on inducing nucleated precipitation of copper and silver in a serpentine reactor, using sodium sulfide as the precipitator, and sulfuric acid for pH control. Results show that pH value has a significant effect on copper cyanide removal efficiency, and it was determined the optimal pH range to be 2.5 - 3. At this pH value, the copper cyanide removal efficiency achieved was up to 97 and 99%, when copper concentration in the influent was 636 and 900 ppm. respectively. In this process (sulphidization-acidification-thickening-HCN recycling), the cyanide associated with copper cyanide complexes, is released as HCN gas under weakly acidic conditions, allowing it to be recycled back to the cyanidation process as free cyanide. Cyanide recovery was 90%. Finally, this procedure was successfully run at Minera William in México.

关键词： precipitation Cyanide Removal Copper Recovery Cyanidation

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Effects of plant Extracts and Beauveria bassiana on the Activity of Defense-Related Enzymes in Solanum lycopersicum *** Interaction with Fusarium oxysporum ***

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phyton-International Journal of Experimental Botany 2023年第9期92卷 2503-2518页

作者： JoséAdrian perez-Robles Carlos Alberto Lecona-Guzmán víctor Manuel Ruíz-valdiviezo Joaquín Adolfo Montes-Molina Laboratorio de Biotecnología vegetal Tecnológico Nacional de MexicoCampus Tuxtla GutiérrezTuxtla Gutiérrez29050Mexico

The objective to this work was to evaluate the enzymatic activity in the culture of Solanum lycopersicum *** with Fusarium oxysporum after the combined application of Beauveria bassiana and plant *** lycopersicum plantlets were transplanted 15 days after the *** days after transplanting,Beauveria bassiana spores were applied at a concentration of 1×10^(7)spores mL^(−1)onto soil(along with ***(N)and ***(H)leaf extracts)where *** plants were *** days after transplanting,spores of *** strain were applied at a concentration of 1×10^(6)spores mL^(−1)to soil where *** plants were *** development of *** plants was monitored for 114 days,whereby a randomized complete block treatment design was used,the roots of the plants were crushed with liquid nitrogen,after which Uv/vIS spectrophotometry was used to determine protein concentration,as well as the activity ofβ-1,3-glucanases,peroxidases(pOX,EC1.***.1.7),catalase and *** treatments combining *** and *** and *** extracts,had a significant difference in enzymatic activity levels,thus contributing to better defense mechanisms and a greater protection to *** plants in the presence of *** application of *** and plant extracts to the ground mitigated damage caused by *** on *** plants.

关键词： Glucanases chitinases peroxidases catalase defense mechanisms

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Diversity of Saxicolous Lichens along an Aridity Gradient in Central México

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phyton-International Journal of Experimental Botany 2022年第4期91卷 827-840页

作者： JoséCarmen Soto-Correa Abraham Saldaña-vega víctor Hugo Cambrón-Sandoval Laura Concostrina-Zubiri Mariela Gómez-Romero Facultad de Ciencias Naturales Universidad Autónoma de QuerétaroQuerétaro73230México Departamento de Biología y Geología Física y Química Inorgánica Tulipán s/nUniversidad Rey Juan CarlosMóstolesMadrid28933España Cátedra CONACYT–Facultad de Biología Universidad Michoacana de San Nicolás de HidalgoMoreliaMichoacán58030México

Lichens are symbiotic organisms that comprise a fungus and a photosynthetic partner wich are recognized as a good indicator of climate ***,our understanding of how aridity affects the diversity of saxicolous lichens in drylands is still *** evaluate the relationship between saxicolous lichen diversity and aridity in a central México dryland,a geographical transect was established of 100 km to build an aridity gradient in the semiarid zone of the State of Querétaro,Mexico,comprising ten sampling sites with a 10 km *** richness,abundance and diversity of soil lichen species were recorded using two sampling methods:the quadrat-intercept and the line-intercept method,to compare their performance in assessing soil lichen diversity in *** number of species and Shannon diversity of saxicolous lichens were higher at intermediate values of the aridity index(AI=0.10-0.34).Quadrat intercept and point intercept methods gave quite similar results,which means that the selected method does not influence the results in a significant *** study confirms the role of saxicolous lichens as climate change indicators and reveals the importance of the sampling method selection in the evaluation of different parameters of soil lichen diversity in drylands.

关键词： Climate change drylands ecological indicators environmental stress precipitation temperature

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Getting started in mapping-by-sequencing

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Journal of Integrative plant Biology 2015年第7期57卷 606-612页

作者： Héctor Candela Rubén Casanova-Sáez José Luis Micol Instituto de Bioingeniería Universidad Miguel Hernández Department of Forest Genetics and plant physiology Umea Plant Science CenterSwedish University of Agricultural Sciences

Next-generation sequencing （NGS） technologies allow the cost-effective sequencing of whole genomes and have expanded the scope of genomics to novel applications, such as the genome-wide characterization of intraspecific polymorphisms and the rapid mapping and identification of point mutations. Next-generation sequencing platforms, such as the Illumina HiSeq2ooo platform, are now commercially available at affordable prices and routinely produce an enormous amount of sequence data, but their wide use is often hindered by a lack of knowledge on how to manipulateand process the information produced. In this review, we focus on the strategies that are available to geneticists who wish to incorporate these novel approaches into their research but who are not familiar with the necessary bioinformatic concepts and computational tools. In particular, we comprehensively summarize case studies where the use of NGS technologies has led to the identification of point mutations, a strategy that has been dubbed ＂mapping-by-sequencing＇, and review examples from plants and other model species such as Caenorhabditis elegans, Saccharomyces cerevisiae, and Drosophila mela- nogaster. As these technologies are becoming cheaper and more powerful, their use is also expanding to allow mutation identification in species with larger genomes, such as many crop plants.

关键词： Mapping-by-sequencing massively parallel sequencing mutation identification SHOREmapping whole-genome re-sequencing

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Decreased concentrating capacity in children with febrile urinary tract infection and normal 99mTc-dimercaptosuccinic acid scan:does medullonephritis exist?

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World Journal of pediatrics 2014年第2期10卷 133-137页

作者： víctor García-Nieto Silvia González-Cerrato María Isabel Luis-Yanes Margarita Monge-Zamorano Beatriz Reyes-Millán pediatric Nephrology Section "Nuestra Senra de la Candelaria"University HospitalSanta Cruz de TenerifeCanary IslandsSpain

Background:Although 99mTc-dimercaptosuccinic acid(DMSA)scan is considered the gold standard for the diagnosis of acute pyelonephritis(Ap),sometimes it produces false results in children with clinical features of *** are no studies on the comparison of the sensitivity of DMSA and concentrating capacity ***:Eighty-fi ve infants with Ap of less than one year old were studied to evaluate whether they had real Ap or *** were compared between infants with an abnormal(group A,n=64)and those with a normal DMSA scan(group B,n=21)respectively.A DDAvp test was performed for each ***:All the infants in both groups presented a high level of C-reactive protein and fever(≥38oC).There were no differences in clinical and analytical variables except C-reactive protein level in the two *** groups exhibited a low urinary osmolality(87.5%in the group A vs.85.7%in the group B).The patients with normal DMSA and decreased concentrating capacity have some renal parenchymal damage and not only a lower urinary *** the infants with an abnormal DMSA scan,33.9%showed renal scars after 6-12 *** infant with a normal DMSA scan showed *** biochemical variables in both groups of infants were not related to vesicoureteral refl ***:Infants with Ap,normal DMSA scan and low concentrating capacity may be characterized by a localized infection in the medulla(medullonephritis)or by a false negative DMSA scan.

关键词： concentrating capacity infants pyelonephritis urinary tract infection

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Chitosan conduits enriched with fibrin-collagen hydrogel with or without adipose-derived mesenchymal stem cells for the repair of 15-mm-long sciatic nerve defect

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Neural Regeneration Research 2023年第6期18卷 1378-1385页

作者： Marwa El Soury óscar Darío García-García Isabella Tarulli Jesús Chato-Astrain Isabelle perroteau Stefano Geuna Stefania Raimondo Giovanna Gambarotia víctor Carriel Department of Clinical and Biological Sciences University of TorinoTorinoItaly Neuroscience Institute Cavalieri Ottolenghi University of TorinoTorinoItaly Department of Histology Tissue Engineering GroupUniversity of GranadaGranadaSpain Instituto de Investigacion Biosanitaria Ibs.GRANADAGranadaSpain

Hollow conduits of natural or synthetic origins have shown acceptable regeneration results in short nerve gap repair;however,results are still not comparable with the current gold standard technique“autografts”.Hollow conduits do not provide a successful regeneration outcome when it comes to critical nerve gap *** the lumen of conduits with different extracellular materials and cells could provide a better biomimicry of the natural nerve regenerating environment and is expected to ameliorate the conduit *** this study,we evaluated nerve regeneration in vivo using hollow chitosan conduits or conduits enriched with fibrin-collagen hydrogels alone or with the further addition of adipose-derived mesenchymal stem cells in a 15 mm rat sciatic nerve transection *** changes in the hydrogel consistency and structural stability in vivo led to a failure of nerve regeneration after 15 ***,the molecular assessment in the early regeneration phase(7,14,and 28 days)has shown an upregulation of useful regenerative genes in hydrogel enriched conduits compared with the hollow *** composed of fibrin-collagen were able to upregulate the expression of soluble NRG1,a growth factor that plays an important role in Schwann cell *** further enrichment with adipose-derived mesenchymal stem cells has led to the upregulation of other important genes such as ErbB2,vEGF-A,BDNF,c-Jun,and ATF3.

关键词： adipose-derived stem cells chitosan conduit fibrin and collagen hydrogel nerve regeneration nerve repair neuregulin 1 peripheral nerve sciatic nerve

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Kinetic Rates of the Fischer Tropsch Synthesis on a Co/Nb_2O_5 Catalyst

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Journal of Natural Gas Chemistry 2006年第4期15卷 307-312页

作者： víctor R.Ahón paulo L.C.Lage Carlos D.D.de Souza Fabiana M.Mendes Martin Schmal Federal University of Rio de Janeiro programa de Engenharia Química COPPE/UFRJ C.P.6850221941-972Rio de JaneiroRJBrazil

The kinetics of the Fischer-Tropsch reaction over a Co/Nb2O5 catalyst in a fixed bed reactor was investigated experimentally. Experiments were carried out under isothermal and isobaric conditions （T=543 K, p=2.1 Mpa） and under different conditions of several H2/CO feed molar ratio （0.49-4.79）, space velocities （0.2-3.8 h^-1）, mass of catalyst （0.3-1.5 g）, and CO conversion （10%-29%）. Synthesis gas conversion was measured and data were reduced to estimate the kinetic parameters for different Langmuir-Hinshelwood rate expressions. Differential and integral reactor models were used for the nonlinear regression of kinetics parameters. One of the rate equations could well explain the data. The hydrocarbon product distributions that were experimentally determined exhibited an unusual behavior, and a possible explanation was discussed.

关键词： Fischer-Tropsch natural gas kinetics selectivity

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