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Dendritic spine degeneration:a primary mechanism in the aging process 被引量:1
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作者 Gonzalo Flores Leonardo Aguilar-Hernández +3 位作者 Fernado García-Dolores Humberto Nicolini Andrea Judith Vázquez-Hernández Hiram Tendilla-Beltrán 《Neural Regeneration Research》 SCIE CAS 2025年第6期1696-1698,共3页
Recent reports suggest that aging is not solely a physiological process in living beings;instead, it should be considered a pathological process or disease(Amorim et al., 2022). Consequently, this process involves a w... Recent reports suggest that aging is not solely a physiological process in living beings;instead, it should be considered a pathological process or disease(Amorim et al., 2022). Consequently, this process involves a wide range of factors, spanning from genetic to environmental factors, and even includes the gut microbiome(GM)(Mayer et al., 2022). All these processes coincide at some point in the inflammatory process, oxidative stress, and apoptosis, at different degrees in various organs and systems that constitute a living organism(Mayer et al., 2022;AguilarHernández et al., 2023). 展开更多
关键词 AGING PROCESS STRESS
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Frugalmodel predictive control and active disturbance rejection for laser beam steering systems
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作者 Rafael Isaac Vázquez-Cruz Ernesto Castellanos-Velasco José Fermi Guerrero-Castellanos 《Control Theory and Technology》 2025年第3期513-528,共16页
This paper aims to fuse two well-established and,at the same time,opposed control techniques,namely,model predictive control(MPC)and active disturbance rejection control(ADRC),to develop a dynamic motion controller fo... This paper aims to fuse two well-established and,at the same time,opposed control techniques,namely,model predictive control(MPC)and active disturbance rejection control(ADRC),to develop a dynamic motion controller for a laser beam steering system.The proposed technique uses the ADRC philosophy to lump disturbances and model uncertainties into a total disturbance.Then,the total disturbance is estimated via a discrete extended state disturbance observer(ESO),and it is used to(1)handle the system constraints in a quadratic optimization problem and(2)injected as a feedforward term to the plant to reject the total disturbance,together with the feedback term obtained by the MPC.The main advantage of the proposed approach is that the MPC is designed based on a straightforward integrator-chain model such that a simple convex optimization problem is performed.Several experiments show the real-time closed-loop performance regarding trajectory tracking and disturbance rejection.Owing to simplicity,the self-contained approach MPC+ESO becomes a Frugal MPC,which is computationally economical,adaptable,efficient,resilient,and suitable for applications where on-board computational resources are limited. 展开更多
关键词 Frugal model predictive control(FMPC) Active disturbance rejection control(ADRC) Laser beam steering system(LBS) Real-time application Constrained systems
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Update on vascular endothelial Ca^(2+) signalling:A tale of ion channels,pumps and transporters 被引量:2
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作者 Francesco Moccia Roberto Berra-Romani Franco Tanzi 《World Journal of Biological Chemistry》 CAS 2012年第7期127-158,共32页
A monolayer of endothelial cells (ECs) lines the lumen of blood vessels and forms a multifunctional transducing organ that mediates a plethora of cardiovascular processes. The activation of ECs from as state of quiesc... A monolayer of endothelial cells (ECs) lines the lumen of blood vessels and forms a multifunctional transducing organ that mediates a plethora of cardiovascular processes. The activation of ECs from as state of quiescence is, therefore, regarded among the early events leading to the onset and progression of potentially lethal diseases, such as hypertension, myocardial infarction, brain stroke, and tumor. Intracellular Ca2+ signals have long been know to play a central role in the complex network of signaling pathways regulating the endothelial functions. Notably, recent work has outlined how any change in the pattern of expression of endothelial channels, transporters and pumps involved in the modulation of intracellular Ca2+ levels may dramatically affect whole body homeostasis. Vascular ECs may react to both mechanical and chemical stimuli by generating a variety of intracellular Ca2+ signals, ranging from brief, localized Ca2+ pulses to prolonged Ca2+ oscillations engulfing the whole cytoplasm. The well-defined spatiotemporal profile of the subcellular Ca2+ signals elicited in ECs by specific extracellular inputs depends on the interaction between Ca2+ releasing channels, which arelocated both on the plasma membrane and in a number of intracellular organelles, and Ca2+ removing systems. The present article aims to summarize both the past and recent literature in the field to provide a clear-cut picture of our current knowledge on the molecular nature and the role played by the components of the Ca2+ machinery in vascular ECs under both physiological and pathological conditions. 展开更多
关键词 Endothelial cells CA2+ SIGNALLING Plasma membrane Endoplasmic reticulum Intracellular CA2+ release CA2+ entry CA2+ removal CA2+ oscillations
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Potential seed germination-enhancing plant growth-promoting rhizobacteria for restoration of Pinus chiapensis ecosystems 被引量:2
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作者 Cristina Domínguez-Castillo Julia María Alatorre-Cruz +5 位作者 Dolores Castañeda-Antonio Jose Antonio Munive Xianwu Guo Jesús Francisco López-Olguín Luis Ernesto Fuentes-Ramírez Ricardo Carreño-López 《Journal of Forestry Research》 SCIE CAS CSCD 2021年第5期2143-2153,共11页
Rhizosphere soil samples of three Pinus chiapensis sites were analyzed for their physicochemical properties,soil bacteria isolated and screened in vitro for growthpromoting abilities.Nine isolates that showed promise ... Rhizosphere soil samples of three Pinus chiapensis sites were analyzed for their physicochemical properties,soil bacteria isolated and screened in vitro for growthpromoting abilities.Nine isolates that showed promise were identified to five genera Dyella,Luteimonas,Euterobacter,Paraburkholderia and Bacillus based on the sequences of16 S rRNA gene.All the strains were isolated from nondisturbed stands.These bacteria significantly decreased germination time and increased sprout sizes.Indole acetic acid and gibberellin production and phosphate solubilisation were detected.Results indicate that these biochemicals could be essential for P.chiapensis distribution and suggest the possibility that PGPR inoculation on P.chiapensis seeds prior to planting could improve germination and possibly seedling development. 展开更多
关键词 Pinus chiapensis Plant growth-promoting rhizobacteria Dyella Luteimonas ENTEROBACTER
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The Tension between New Media and Narratology: The Case of Cinema 被引量:1
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作者 Alberto J. L. Carrillo, Marco Calder6n, Francisco J. Montes May Zindel 《Journal of Philosophy Study》 2012年第9期677-687,共11页
We will discuss here the tension between the reality of new media and narratological theory, and the case in point will be cinema. Our thesis is that new media have to do with illusion, basically with illusion, and on... We will discuss here the tension between the reality of new media and narratological theory, and the case in point will be cinema. Our thesis is that new media have to do with illusion, basically with illusion, and only derivatively with imagination; on the contrary, the field of literature has to do with imagination, strictly with imagination, not with illusion at all. If it is so, something must be wrong with the pretence of narratology, which has literature as its basic referent, to be the adequate theoretical frame in order to understand every cultural phenomenon, especially in the case of new media. We have to insist on the distinction between illusion and imagination. In fact, most literary theorists do not bear in mind such distinction; it tends to completely disappear under the general title "fiction." To be sure, it is usually said of cinema that it is fiction, like literature, but cinema is much more than fiction, it is illusion, even if it is the illusion of a story. 展开更多
关键词 IMAGINATION ILLUSION plastic imagination aesthetic belief sameness of the character
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Adhesion of <i>Gallibacterium anatis</i>to Chicken Oropharyngeal Epithelial Cells and the Identification of Putative Fimbriae 被引量:9
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作者 Mónica L. Salgado Lucio Sergio Vaca +4 位作者 Candelario Vázquez Edgar Zenteno Ismael Rea Víctor M. Pérez-Márquez Erasmo Negrete-Abascal 《Advances in Microbiology》 2012年第4期505-510,共6页
Microbial infections are typically initiated by the colonization of tissues by a specific mechanism that promotes adherence to host cells or tissues. In this work, we characterized the ability of Gallibacterium anatis... Microbial infections are typically initiated by the colonization of tissues by a specific mechanism that promotes adherence to host cells or tissues. In this work, we characterized the ability of Gallibacterium anatis F149T to express fimbriae that may be involved in mucosal attachment. Using transmission electron microscopy, the fimbriae-like structures could be observed on the surface of negatively stained G. anatis F149T, and these structures were further visualized after being released by physical shaking. When the fimbriae-like structures were separated by SDS-PAGE, the proteins comprising them were isolated and sized at 13 and 25 kDa. G. anatis F149T was able to adhere to chicken oropharyngeal epithelial cells. Adhesion could be completely inhibited by pretreatment of the bacterial cells with trypsin, whereas 25% inhibition was attained after pretreatment with an antiserum against the 13 kDa protein. We demonstrated by immuno-gold electron microscopy that the antibodies from the antiserum were specifically associated with the fimbria-like structures on G. anatis. These results indicated that G. anatis F149T expresses fimbriae that contribute to its adhesion to chicken oropharyngeal epithelial cells and may be important for colonization of the upper respiratory tract. 展开更多
关键词 G. anatis ADHESION FIMBRIA PILI
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Resveratrol effects on neural connectivity during aging 被引量:3
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作者 Gonzalo Flores Rubén Antonio Vázquez-Roque Alfonso Diaz 《Neural Regeneration Research》 SCIE CAS CSCD 2016年第7期1067-1068,共2页
Aging has been considered a natural process of any living being.The rate of aging depends on many factors,including genetic and environmental factors.For this reason,many researchers in this field suggest that aging i... Aging has been considered a natural process of any living being.The rate of aging depends on many factors,including genetic and environmental factors.For this reason,many researchers in this field suggest that aging is an epigenetic process.Nowadays,the age groups have undergone a change. 展开更多
关键词 resveratrol connectivity older hippocampus neuronal metabolism cortical Aging cortex PPAR
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Detection of Mycoplasmas in Patients with Amyotrophic Lateral Sclerosis 被引量:1
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作者 Constantino Gil Alma Aurora Sánchez González +3 位作者 Isidro Lecona León Antonio Rivera Rayo Santellán Olea Lilia Cedillo 《Advances in Microbiology》 2014年第11期712-719,共8页
Amyotrophic Lateral Sclerosis (ALS) is a progressive degenerative disease of the motor neurons and the cause is unknown. Diverse factors such as genetic defects, nutritional deficiencies, head trauma, environmental to... Amyotrophic Lateral Sclerosis (ALS) is a progressive degenerative disease of the motor neurons and the cause is unknown. Diverse factors such as genetic defects, nutritional deficiencies, head trauma, environmental toxin, autoimmune responses and viral and bacterial infections are involved. Mycoplasmas have been implicated as causal agents of different illnesses in human. The purpose of this study was to investigate the presence of mycoplasmas in the bloodstream of patients with ALS. Patients with ALS and healthy individuals were included in the study. A blood sample was taken in tubes with or without anticoagulant. Mycoplasmas were detected by culture or direct PCR, and the presence of antibodies IgM and IgG against LAMPs of these microorganisms by Western blot. Cultures for aerobic facultative bacteria were also done. Blood samples from 13 patients and 44 healthy individuals were screened. All blood cultures for non-fermentative mycoplasmas and aerobic facultative bacteria were negative. Cultures for fermentative mycoplasmas were considered positive after identification of mycoplasmal DNA by PCR. Mycoplasma sp. was detected by culture or direct PCR in 6/13 (46%) patients and in 4/44 (9%) of healthy individuals. M. fermentans was detected by PCR using specific primers in six patients and in two healthy individuals. IgM against LAMPs of M. fermentans were detected in 6/13 (46%) blood samples from patients and in 13/44 (30%) from healthy individuals, while. IgG was detected in 4/13 (31%) patients and in 3/44 (7%) healthy individuals. The results of this study show that mycoplasmas cause a systemic infection and could play a role in the origin or progression of the ALS. 展开更多
关键词 Amyotrophic LATERAL SCLEROSIS MYCOPLASMAS IMMUNE RESPONSE
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Using remotely sensed and climate data to predict the current and potential future geographic distribution of a bird at multiple scales: the case of Agelastes meleagrides, a western African forest endemic 被引量:1
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作者 Benedictus Freeman Daniel Jiménez-García +1 位作者 Benjamin Barca Matthew Grainger 《Avian Research》 CSCD 2019年第3期262-270,共9页
Background:Understanding geographic distributions of species is a crucial step in spatial planning for biodiversity conservation, particularly as regards changes in response to global climate change.This information i... Background:Understanding geographic distributions of species is a crucial step in spatial planning for biodiversity conservation, particularly as regards changes in response to global climate change.This information is especially important for species of global conservation concern that are susceptible to the effects of habitat loss and climate change. In this study, we used ecological niche modeling to assess the current and future geographic distributional potential of White.breasted Guineafowl (Agelastes meleagrides)(Vulnerable) across West Africa. Methods:We used primary occurrence data obtained from the Global Biodiversity Information Facility and national parks in Liberia and Sierra Leone, and two independent environmental datasets (Moderate Resolution Imaging Spectroradiometer normalized difference vegetation index at 250 m spatial resolution, and Worldclim climate data at 2.5' spatial resolution for two representative concentration pathway emissions scenarios and 27 general circulation models for 2050) to build ecological niche models in Maxent. Results: From the projections, White.breasted Guineafowl showed a broader potential distribution across the region compared to the current IUCN range estimate for the species. Suitable areas were concentrated in the Gola rainforests in northwestern Liberia and southeastern Sierra Leone, the Tai.Sapo corridor in southeastern Liberia and southwestern Cote d'lvoire, and the Nimba Mountains in northern Liberia, southeastern Guinea, and northwestern Cote d'lvoire.Future climate.driven projections anticipated minimal range shifts in response to climate change. Conclusions: By combining remotely sensed data and climatic data, our results suggest that forest cover, rather than climate is the major driver of the species' current distribution. Thus, conservation efforts should prioritize forest protection and mitigation of other anthropogenic threats (e.g.hunting pressure) affecting the species. 展开更多
关键词 Climate change Conservation Conservation planning Ecological niche modeling Species distribution Upper Guinea Forest White-breasted Guineafowl
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Modified combustion synthesis of g-LiAlO_2 using metal oxides 被引量:1
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作者 Daniel CRUZ H.B.ORTIZ-OLIVEROS +2 位作者 L.M.PéREZ-DíAZ R.M.FLORES-ESPINOSA G.ROSANO-ORTEGA 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2018年第9期1793-1800,共8页
An alternative solution for the direct formation of?-LiAlO2 was presented by a modified combustion method,to apply it to rather simple systems,utilizing non-oxidizer compounds such as Al2O3 and LiOH,and urea as fuel.L... An alternative solution for the direct formation of?-LiAlO2 was presented by a modified combustion method,to apply it to rather simple systems,utilizing non-oxidizer compounds such as Al2O3 and LiOH,and urea as fuel.LiAlO2 was prepared via non-stoichiometric 1:1,1.5:1 and 2:1 of Li/Al molar ratios at 900 and 1000°C for 5 min.Textural and structural characterization ofγ-LiAlO2 was performed.Also,the effect of different Li/Al molar ratios on material morphology and its stability before high gamma radiation gradients was evaluated.The results showed that the crystal structures of the obtained powders wereγ-LiAlO2 and?-LiAlO2,depending on the Li/Al molar ratio.The results obtained demonstrate that?-LiAlO2 microbricks,polyhedral and laminar shapes can be successfully synthesized with the proposed method and without any subsequent process.Additionally,gamma irradiation showed that the?-LiAlO2 obtained does not decompose,forming only small amounts of Li2CO3.It can be established that the irradiation produces consolidation,which is not favourable for an efficient extraction of tritium.Finally,it could be demonstrated that nitrate precursors are not necessary in the combustion method to produceγ-LiAlO2 with high purity. 展开更多
关键词 UREA OXIDE COMBUSTION lithium aluminate CERAMIC
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Chemical Characterisation of the Industrial Residues of the Pineapple (Ananas comosus) 被引量:1
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作者 María Elena Sánchez Pardo María Elena Ramos Cassellis +1 位作者 Rosalva Mora Escobedo Epifanio Jiménez García 《Journal of Agricultural Chemistry and Environment》 2014年第2期53-56,共4页
In Mexico pineapple processing produces industrial residues with a high concentration of dietary fibre. The aim of this study was to quantify the constituents of the fibrous residues from the industrial processing of ... In Mexico pineapple processing produces industrial residues with a high concentration of dietary fibre. The aim of this study was to quantify the constituents of the fibrous residues from the industrial processing of pineapples which exhibited low concentrations of lignin. 展开更多
关键词 PINEAPPLE Total DIETARY FIBRE Hemicelluloses CELLULOSE LIGNIN PECTIN
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Presence of Mycoplasma Spp.in Patients with Asthma or Allergic Rhinitis 被引量:1
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作者 Munoz-Zurita Guillermo Paz Martínez David +2 位作者 Yánez Santos Jorge Antonio Gil Juárez Constantino Cedillo Ramírez María Lilia 《Advances in Microbiology》 2014年第11期720-725,共6页
Objective: To compare the presence of Mycoplasma spp. in pharyngeal swabs of patients with asthma, allergic rhinitis and controls, also to compare the reactivity to allergens in the three groups. Material and Methods:... Objective: To compare the presence of Mycoplasma spp. in pharyngeal swabs of patients with asthma, allergic rhinitis and controls, also to compare the reactivity to allergens in the three groups. Material and Methods: Throat swabs of 120 patients with asthma, 211 allergic rhinitis patients and 171 healthy persons were cultured in E media. Positive cultures were identified by PCR. Susceptibility of patients positive for isolation of Mycoplasma spp. to indoor, forest and undergrowth allergens were determined. Results: Mycoplasma spp. was isolated in 26.6% of samples from asthmatic patients, 36% in patients with allergic rhinitis and 2.9% in the group of healthy persons. Positive patients for Mycoplasma with asthma and allergic rhinitis showed susceptibility tomite, grass and thunder mainly. Conclusion: There is a higher incidence of Mycoplasma spp. in asthmatic and allergic rhinitis patients than healthy persons. Only patients with asthma or allergic rhinitis showed reactivity to environmental allergens. 展开更多
关键词 ASTHMA Allergic Rhinitis Allergens Mycoplasma Spp.
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Potential role of noise to improve intracortical microstimulation in tactile neuroprostheses
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作者 Pedro Mabil Nayeli Huidobro +1 位作者 Amira Flores Elias Manjarrez 《Neural Regeneration Research》 SCIE CAS CSCD 2021年第8期1533-1534,共2页
The intracortical microstimulation(ICMS) from 40 to 100 μA is useful to elicit tactile sensations,which could be employed in neuroprostheses to control the robotic arms' movement.However,this electrical current a... The intracortical microstimulation(ICMS) from 40 to 100 μA is useful to elicit tactile sensations,which could be employed in neuroprostheses to control the robotic arms' movement.However,this electrical current applied for prolonged periods of time could damage the neuronal tissue.Therefore,there is a necessity to create new strategies for the practical use of ICMS in a safe intensity range for potential clinical applications in tetraplegic patients.Here we describe crucial studies supporting the use of electrical and optical noise to guarantee a safe ICMS delivered through brain-machine interface technologies. 展开更多
关键词 GUARANTEE SUPPORTING SENSATION
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Conditions Where the Chaotic Set Has a Non-Empty Residual Julia Set for Two Classes of Meromorphic Functions
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作者 Patricia Domínguez Iván Hernández 《Applied Mathematics》 2013年第11期18-21,共4页
We define the Fatou and Julia sets for two classes of meromorphic functions. The Julia set is the chaotic set where the fractals appear. The chaotic set can have points and components which are buried. The set of thes... We define the Fatou and Julia sets for two classes of meromorphic functions. The Julia set is the chaotic set where the fractals appear. The chaotic set can have points and components which are buried. The set of these points and components is called the residual Julia set, denoted by , and is defined to be the subset of those points of the Julia set, chaotic set, which do not belong to the boundary of any component of the Fatou set (stable set). The points of are called buried points and the components of are called buried components. In this paper we extend some results related with the residual Julia set of transcendental meromorphic functions to functions which are meromorphic outside a compact countable set of essential singularities. We give some conditions where . 展开更多
关键词 Fatou SET Julia SET RESIDUAL Julia SET BURIED Points BURIED Components
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Experiment Design for the Location-Allocation Problem
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作者 María Beatríz Bernábe Loranca Rogelio González Velázquez +3 位作者 Martín Estrada Analco Mario Bustillo Díaz Gerardo Martínez Guzman Abraham Sánchez López 《Applied Mathematics》 2014年第14期2168-2183,共16页
The allocation of facilities and customers is a key problem in the design of supply chains of companies. In this paper, this issue is approached by partitioning the territory in areas where the distribution points are... The allocation of facilities and customers is a key problem in the design of supply chains of companies. In this paper, this issue is approached by partitioning the territory in areas where the distribution points are allocated. The demand is modelled through a set of continuous functions based on the population density of the geographic units of the territory. Because the partitioning problem is NP hard, it is necessary to use heuristic methods to obtain reliable solutions in terms of quality and response time. The Neighborhood Variable Search and Simulated Annealing heuristics have been selected for the study because of their proven efficiency in difficult combinatorial optimization problems. The execution time is the variable chosen for a factorial experimental design to determine the best-performing heuristics in the problem. In order to compare the quality of the solutions in the territorial partition, we have chosen the execution time as the common parameter to compare the two heuristics. At this point, we have developed a factorial statistical experimental design to select the best heuristic approaches to this problem. Thus, we generate a territorial partition with the best performing heuristics for this problem and proceed to the application of the location-allocation model, where the demand is modelled by a set of continuous functions based on the population density of the geographical units of the territory. 展开更多
关键词 DEMAND EXPERIMENTAL DESIGN HEURISTICS Location-Allocation Partitioning.
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Molecular Docking Studies of Estrone-Coumarin Derivatives as Aromatase and 17β-HSD1 Inhibitors Related to Hormone Receptor Positive (HR+) Breast Cancer
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作者 Silvia Alejandra Meza-Ireta Blanca Colin-Lozano +2 位作者 Penélope Merino-Montiel José Luis Vega-Báez Sara Montiel-Smith 《Advances in Enzyme Research》 CAS 2022年第4期83-100,共18页
Hormone Receptor positive (HR+) breast cancer is the most common malignancy in women. New strategies in the treatments have targeted the estrogen biosynthesis pathways including the inhibition of the aromatase and 17... Hormone Receptor positive (HR+) breast cancer is the most common malignancy in women. New strategies in the treatments have targeted the estrogen biosynthesis pathways including the inhibition of the aromatase and 17β-HSD1 enzymes. The present work, describes the study of a new family of 9 hybrid compounds derived from estrone attached to a coumarin fragment, linked through different lengths of hydrocarbon chains. The activity of these compounds was evaluated by molecular docking with two relevant enzymes in breast cancer (HR+). It has been proposed nine compounds as 17β-HSD1 inhibitors and six as aromatase inhibitors. We found important interactions with key amino acids at the orthosteric site of each enzyme and their score values compared to the crystallographic ligand. The in silico analysis showed good score values in the proposed compounds, where the steroidal portion presented important interactions with Met374 and Tyr155 in aromatase and in 17β-HSD1 respectively. Highlighting Compounds 2, 5 and 8 with an aromatic ring at the C4 position of the coumarin moiety, which favored arene-H type interactions essential for protein-ligand recognition. In addition, the results related to the 17β-HSD1 enzyme demonstrated how the length of the linker influences the interaction;the best score was found for derivative 8 with a chain of 8 methylenes. 展开更多
关键词 ESTRONE COUMARINS Aromatase Inhibitors 17β-HSD1 Inhibitors Molecular Docking
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Study of the Reactivity of (100) Felodipine Surface Model Based on DFT Concepts
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作者 Carlos Tepech-Carrillo Roxana Licona-Ibarra +1 位作者 J. Francisco Rivas-Silva Antonio Flores-Riveros 《Open Journal of Physical Chemistry》 2019年第1期1-12,共12页
In this study, Density Functional Theory including a dispersion correction is employed to model and analyze the structural, electronic and local reactivity of the (100) surface of felodipine. The surface energy calcul... In this study, Density Functional Theory including a dispersion correction is employed to model and analyze the structural, electronic and local reactivity of the (100) surface of felodipine. The surface energy calculated at the Generalized Gradient Approximation (GGA) level, along with plane waves as basis set and ultrasoft pseudopotentials, shows that the (100) surface is the most stable as compared to the (010) and (110) ones. In particular, we have focused on performing a quantitative study of the reactivity of the surface by means of the Fukui function and through the HOMO and LUMO populations. Our results can be related to some applications in the pharmaceutical chemistry of this compound. 展开更多
关键词 1 4-Dihydropyridine FELODIPINE Density FUNCTIONAL Theory Fukui FUNCTIONS
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Logistic Methods in Calculating Mortality Index in Hidalgo México
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作者 Gerardo Martínez-Guzmán Mario Mauricio Bustillo-Díaz +5 位作者 Alejandro Rangel-Huerta Gabriel Juárez-Díaz Apolonio Ata-Pérez Nicolás Quiroz-Hernández Rogelio González-Velázquez María Beatríz Bernabe-Loranca 《Applied Mathematics》 2015年第8期1193-1199,共7页
Mortality projections in a population are based on the prior analysis of mortality in a region, hoever, there are populations where data are not available or not reflect its real mortality level, that is, the projecti... Mortality projections in a population are based on the prior analysis of mortality in a region, hoever, there are populations where data are not available or not reflect its real mortality level, that is, the projections depend on hypothesis strength of previous data. Based on these assumptions, the mathematical method Genova I Maleras 1997 used the most recent data and the model tables from the United Nations (UN). This method was applied to a mortality survey of the population of Hidalgo State, Mexico, projecting to year 2030. This method has not been applied in Mexico. 展开更多
关键词 MORTALITY PROJECTION Genova I Maleras Method
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Redshift of Excitation Wavelength Caused by the Concentration of L-Tryptophan in Water: A Theoretical and Experimental Study
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作者 Diana Milena Uriza-Prias Antonio Méndez-Blas Juan Francisco Rivas-Silva 《Open Journal of Physical Chemistry》 2021年第2期87-105,共19页
A redshift in the wavelength of excitation spectra is experimentally measured as a function of the concentration parameter for tryptophan solutions in water. To understand the microscopic causes of this behavior, theo... A redshift in the wavelength of excitation spectra is experimentally measured as a function of the concentration parameter for tryptophan solutions in water. To understand the microscopic causes of this behavior, theoretical calculations obtained from four model clusters are carried out: (</span><span style="font-family:Verdana;"><i></span><i><span style="font-family:Verdana;">Trp</span></i><i><span style="font-family:Verdana;"></i></span></i><span style="font-family:""><span style="font-family:Verdana;">)</span><sub><span style="font-family:Verdana;">1</span></sub> </span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;"> (</span><span style="font-family:Verdana;"><i></span><i><span style="font-family:Verdana;">H</span></i><sub><span style="font-family:Verdana;">2</span></sub><i><span style="font-family:Verdana;">O</span></i><i><span style="font-family:Verdana;"></i></span></i><span style="font-family:""><span style="font-family:Verdana;">)</span><sub><span style="font-family:Verdana;">9</span></sub><span style="font-family:Verdana;">, (</span></span><span style="font-family:Verdana;"><i></span><i><span style="font-family:Verdana;">Trp</span></i><i><span style="font-family:Verdana;"></i></span></i><span style="font-family:""><span style="font-family:Verdana;">)</span><sub><span style="font-family:Verdana;">2</span></sub> </span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;"> (</span><span style="font-family:Verdana;"><i></span><i><span style="font-family:Verdana;">H</span></i><sub><span style="font-family:Verdana;">2</span></sub><i><span style="font-family:Verdana;">O</span></i><i><span style="font-family:Verdana;"></i></span></i><span style="font-family:""><span style="font-family:Verdana;">)</span><sub><span style="font-family:Verdana;">18</span></sub><span style="font-family:Verdana;">, (</span></span><span style="font-family:Verdana;"><i></span><i><span style="font-family:Verdana;">Trp</span></i><i><span style="font-family:Verdana;"></i></span></i><span style="font-family:""><span style="font-family:Verdana;">)</span><sub><span style="font-family:Verdana;">3</span></sub> </span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;"> (</span><span style="font-family:Verdana;"><i></span><i><span style="font-family:Verdana;">H</span></i><sub><span style="font-family:Verdana;">2</span></sub><i><span style="font-family:Verdana;">O</span></i><i><span style="font-family:Verdana;"></i></span></i><span style="font-family:""><span style="font-family:Verdana;">)</span><sub><span style="font-family:Verdana;">27</span></sub><span style="font-family:Verdana;"> and (</span></span><span style="font-family:Verdana;"><i></span><i><span style="font-family:Verdana;">Trp</span></i><i><span style="font-family:Verdana;"></i></span></i><span style="font-family:""><span style="font-family:Verdana;">)</span><sub><span style="font-family:Verdana;">4</span></sub> </span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;"> (</span><span style="font-family:Verdana;"><i></span><i><span style="font-family:Verdana;">H</span></i><sub><span style="font-family:Verdana;">2</span></sub><i><span style="font-family:Verdana;">O</span></i><i><span style="font-family:Verdana;"></i></span></i><span style="font-family:""><span style="font-family:Verdana;">)</span><sub><span style="font-family:Verdana;">36</span></sub><span style="font-family:Verdana;">, where there are interactions among 1, 2, 3 and 4 molecules of tryptophan. According to the literature, each interaction occurred with nine molecules of water to stabilize its expected zwitterionic form. In these models, the molecules of tryptophan appear at an adjacent distance among them to generate an analogous behavior when there is an experimental increase in the concentration. It is evident that </span><span style="font-family:Verdana;">the distance between adjacent molecules of tryptophan decreases as their concentration</span><span style="font-family:Verdana;"> increases. The optical properties of these clusters are obtained by studying the corresponding excited states and the molecular orbitals involved, showing charge transfers by using time-dependent density functional theory (TD-DFT) methods. The experimental spectroscopic data are obtained by using the clusters proposed, and good agreement is found by drawing a comparison with the theoretical data</span></span><span style="font-family:Verdana;">. 展开更多
关键词 Excitation Spectra Tryptophan Concentration Polar Solvent Molecular Clusters Time-Dependent Density Functional Theory (TD-DFT) Methods Electronic Transitions Fluorescence
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Synthesis of activated carbons from black sapote seeds,characterization and application in the elimination of heavy metals and textile dyes
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作者 Alejandra Alicia Peláez-Cid Vincent Romero-Hernández +2 位作者 Ana María Herrera-González Alejandro Bautista-Hernández Oscar Coreno-Alonso 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2020年第2期613-623,共11页
Many different techniques may be used to remove industrial pollutants from wastewater. Adsorption using activated carbon has been reported to be an effective method. This work proposes the use of a vegetable residue(b... Many different techniques may be used to remove industrial pollutants from wastewater. Adsorption using activated carbon has been reported to be an effective method. This work proposes the use of a vegetable residue(black sapote seeds) as a raw material for its synthesis. These carbons were chemically activated using phosphoric acid and carbonized at 673 and 873 K. Adsorption isotherms were constructed for the textile dyes on the carbons, and this data was treated using Langmuir’s equation to quantitatively describe the adsorption process. The synthesized carbons were characterized using FTIR, EA, SEM, Nitrogen adsorption(specific surface areas of 879 and 652 m2·g-1), and their points of zero charge(2.1 and 2.3). It was possible to adsorb both heavy metals and textile dyes present in aqueous solutions and wastewaters using these activated carbons. Heavy metals were adsorbed almost completely by both carbons. Cationic dyes where adsorbed(58–59.8 mg·g-1) in greater amounts compared to anionic dyes(10–58.8 mg·g-1). The amount of anionic dyes adsorbed increased almost 30% by changing the pH of the solutions. One of the carbons was thermally regenerated on three occasions without losing its adsorption capacity and it was proved in a flow system. 展开更多
关键词 Activated carbons Black sapote seeds Heavy metal adsorption Textile dye adsorption Wastewater treatment
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