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“Anti-Michael” and Michael Additions in the Reactions of 2-Arylmethyliden-1,3-Indandiones with 2-Aminothiophenol 被引量:1
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作者 Jessica J. Sá nchez Garcí +8 位作者 a Alberto D. Herná ndez-Suzan Elena Martí nez-Klimova Marcos Flores-Alamo Teresa Ramí rez Apan Elena I. Klimova 《International Journal of Organic Chemistry》 2017年第1期57-81,共25页
A novel 2-indano[2,3b]-2-ferrocenyl- and 2-indano[2,3b]-2-(p-methoxy-phenyl)[1,5]benzo-2,5-dihydrothiazepine 5a,b (addition Michael/cyclization) (~30.32%), indano[2,3b]-2-ferrocenyl- and 2-(p-methoxyphenyl)[1,4] benzo... A novel 2-indano[2,3b]-2-ferrocenyl- and 2-indano[2,3b]-2-(p-methoxy-phenyl)[1,5]benzo-2,5-dihydrothiazepine 5a,b (addition Michael/cyclization) (~30.32%), indano[2,3b]-2-ferrocenyl- and 2-(p-methoxyphenyl)[1,4] benzothiazine 4a,b (addition “anti-Michael”/cyclization) (~45.43%), respectively, were obtained by the condensation of 2-ferrocenyl-and 2-(p-methoxy-phenyl)methyliden-1,3-indandiones 1a,b with o-aminothiophenol 2 in the presence of AcOH and HCl. A new “anti-Michael” addition reaction of 1,4-bis-heteronucleophile 2 into 2-arylmethyliden-1,3-indandiones was reported. As a result of this reaction the product 1a,b was obtained. The structures of the resultant compounds were elucidated by IR, 1H and 13C NMR spectroscopy, mass spectrometry, elemental and X-ray diffraction analysis. The in vitro antitumor activity of the obtained products was researched using the following human cancer cell lines: glioblastoma (CNS U-251), prostatic adenocarcinoma (PC-3), chronic myelogenous leukemia (K562), colorectal adenocarcinoma (HCT-15), mammary adenocarcinoma (MCF-7), and small cell lung cancer (SKLU) and the sulforhodamine B (SRB) method. Among these new compounds some thiazine and thiazepine derivatives showed compelling in vitro antitumor effects on cell lines K-562, HCT-15, SKLU-1 and MCF-7. 展开更多
关键词 FERROCENE Addition “Anti-Michael” Reaction CYCLIZATION 1 5-Thiazepines 4-Thiazines Antitumor Cell Lines
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Skeletons of 3D Surfaces Based on the Laplace-Beltrami Operator Eigenfunctions 被引量:1
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作者 Adolfo Horacio Escalona-Buendia Lucila Ivonne Hernández-Martínez +2 位作者 Rarafel Martínez-Vega Julio Roberto Murillo-Torres Omar Nieto-Crisóstomo 《Applied Mathematics》 2015年第2期414-420,共7页
In this work we describe the algorithms to construct the skeletons, simplified 1D representations for a 3D surface depicted by a mesh of points, given the respective eigenfunctions of the Discrete Laplace-Beltrami Ope... In this work we describe the algorithms to construct the skeletons, simplified 1D representations for a 3D surface depicted by a mesh of points, given the respective eigenfunctions of the Discrete Laplace-Beltrami Operator (LBO). These functions are isometry invariant, so they are independent of the object’s representation including parameterization, spatial position and orientation. Several works have shown that these eigenfunctions provide topological and geometrical information of the surfaces of interest [1] [2]. We propose to make use of that information for the construction of a set of skeletons, associated to each eigenfunction, which can be used as a fingerprint for the surface of interest. The main goal is to develop a classification system based on these skeletons, instead of the surfaces, for the analysis of medical images, for instance. 展开更多
关键词 SKELETON CENTERLINE Discrete Laplace-Beltrami OPERATOR EIGENFUNCTIONS GRAPH Theory
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Food Safety and Antimicrobial Resistance an Approach to the Genus <i>Salmonella</i>spp. 被引量:1
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作者 Alejandro de Jesú s Corté +8 位作者 s-Sá nchez Raquel Garcia-Barrientos Hugo Minor-Pé rez Octavio Dublá n-Garcí a Alejandra L. San Martin-Azocar 《Journal of Biosciences and Medicines》 2017年第2期55-71,共17页
Foodborne Illnesses (FI) are considered an important problem in public health for their high levels of morbidity and, in some cases, of mortality in Mexico and around the world. Different agents that cause Foodborne I... Foodborne Illnesses (FI) are considered an important problem in public health for their high levels of morbidity and, in some cases, of mortality in Mexico and around the world. Different agents that cause Foodborne Illnesses, in which biological agents such as the genus Salmonella spp., are included, have been often associated with outbreaks. A continued effort has been observed in the food industry, in collaboration with sanitary authorities on a global scale, through the creation and continued improvement of different procedures to prevent the contamination by Salmonella, in which the elaboration of laboratory methodologies for the detection and isolation of this pathogen in foods and, in such manner, prevents the outbreak of illnesses. However, along with the aforementioned, it has been reported that a few years ago, the appearance of an ever-increasing number of strains of Salmonella spp., in foods with multi-drug resistance to antibiotics which are used in the treatment of its illness, results in a major emphasis on the health issue related to Foodborne Illnesses and, in particular, to those generated by factors of medical dependence such as the increase in recuperation time, costs, and reduction in the number of alternative pharmaceutical treatments. This work presents a general overview of FI, in which illnesses generated by bacteria of the genus Salmonella spp., their detection in a microbiological laboratory, as well as the phenomenon of resistance to antibiotics by these bacteria, and the current and difficult issue reported through different investigations all around the world, of the rise in this phenomenon and its importance in public health, are discussed. 展开更多
关键词 Health SALMONELLOSIS SALMONELLA Food Safety ANTIMICROBIAL Resistance
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Suitability of the Composite Made of Multi Wall Carbon Nanotubes-Polyvinylpyrrolidone for Culturing Invertebrate <i>Helix aspersa</i>Neurons 被引量:1
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作者 Juan Bernal-Martinez Rafael Godínez-Fernández Alfredo Aguilar-Elguezabal 《Journal of Materials Science and Chemical Engineering》 2017年第2期41-50,共10页
Carbon nanotubes have been used as scaffolds for tissue engineering. However, the identification of these nanomaterials disperses in biological solutions and their direct interaction with nerve cells is still controve... Carbon nanotubes have been used as scaffolds for tissue engineering. However, the identification of these nanomaterials disperses in biological solutions and their direct interaction with nerve cells is still controversial. The aim of this work is to characterize the topographic and ultra-structural distribution of the composite made of multi wall carbon nanotubes-polyvinylpyrrolidone (MWCNTs-PVP) deposited on the Helix aspersa neurons and over glass coverslip. Scanning Electron Microscopy (SEM) and Confocal Microscopy (CM) studies were done to analyze the properties of such MWCNTs-PVP composite. The cerebral ganglion of Helix aspersa was treated and incubated with MWCNTs-PVP, fixing it in paraformaldehyde at 4% and was observed with SEM and CM. Although the nanotubes were not labeled or stained with fluorescent compounds, the MWCNTs-PVP deposited on glass and on nerve cells, was observed by the confocal microscope in the reflection mode. In SEM studies, it was observed that MWCNTs-PVP was attached to the surface on neurons. Moreover, in CM studies, it was possible to observe that MWCNTs-PVP was attached to the neuronal membrane, crossing the cell membrane and getting into the cytoplasm. These results support the hypothesis that carbon nanotubes interact with the neuronal cell membrane and can be useful for neuronal tissue engineering. In addition, these results open new alternatives for toxicological studies, in order to elucidate the cytotoxicity of MWCNTs-PVP composite in neurons and other excitable cells. 展开更多
关键词 Multi Wall Carbon Nanotubes Functional Scaffolds NEURONS Helix aspersa Tissue Engineering Brain Repair
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Application of the Weibull Distribution to Estimate the Volume of Water Pumping by a Windmill 被引量:1
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作者 M. Toledo Velázquez J. Herná +4 位作者 ndez Rodrí guez M. Vega Del Carmen F. E. Flores Murrieta G. Tolentino Eslava 《Journal of Power and Energy Engineering》 2016年第9期36-51,共17页
Given the steady increase in use of alternative energy sources to supply part of the energy demand of the world, and considering that Mexico has enough wind resources to produce all the electricity required by the cou... Given the steady increase in use of alternative energy sources to supply part of the energy demand of the world, and considering that Mexico has enough wind resources to produce all the electricity required by the country, in this work, it is carried out the development of a system of wind resource assessment to determine the volume of water that a windmill pumping system can provide in a specific area. To this end, it has developed a computer program for wind resource assessment by measurements of wind speed, direction, temperature, barometric pressure and relative humidity. Measuring equipments were mounted in a wind measurement tower of 10 m high, within the premises of the University of Quintana Roo which is located along the coast. Until this day, there are records over a period of five months of the variables of wind speed, wind direction, temperature, relative humidity and atmospheric pressure. These variables were used for statistical calculations using the Weibull distributions. To give a better use of the calculated data, they were applied to the evaluation of a Pumping System. 展开更多
关键词 Pumping Systems Weibull Distribution Wind Energy WINDMILL
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Compressive Strength of Metakaolin-Based Geopolymers: Influence of KOH Concentration, Temperature, Time and Relative Humidity 被引量:1
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作者 Tania Ariadna Garcí a-Mejí +2 位作者 a Ma. de Lourdes Chávez-Garcí a 《Materials Sciences and Applications》 2016年第11期772-791,共21页
The influence of KOH concentration (8 and 12 M) and curing conditions as temperature (40℃ and 60℃), time (7 and 28 days) and relative humidity (85% and 95% RH), on compressive strength of metakaolin-based geopolymer... The influence of KOH concentration (8 and 12 M) and curing conditions as temperature (40℃ and 60℃), time (7 and 28 days) and relative humidity (85% and 95% RH), on compressive strength of metakaolin-based geopolymers (MK-based GP) was evaluated. Derived from the experimental design technique, and using a factorial design 2<sup>K</sup> with two replications in the center point, eighteen experiments were conducted. The results reveal that the best performance conditions of geopolymerization to develop a higher compressive strength of 20 MPa are 12 M KOH to 60℃ and 85% RH at 28 curing days. With these conditions, the value of relative humidity of 85%, promotes high strength compact samples, and a maximum of 42 MPa at 90 days. The results of significant, compressive design of GP showed that KOH concentration and curing relative humidity were the most important factors, followed by curing time and temperature. The GP were characterized by XRD, and their evolution on compression strength was followed by SEM. 展开更多
关键词 GEOPOLYMERS METAKAOLIN Relative Humidity Potassium Hydroxide Design of Experiments
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Absorbed Dose to Water Rate in a Cyberknife VSI System Reference Field Using Ionization Chambers and Gafchromic Films
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作者 Guerda Massillon-JL Nestor Aragó +4 位作者 n-Martí nez Arnulfo Gó mez-Muñ oz 《International Journal of Medical Physics, Clinical Engineering and Radiation Oncology》 2017年第1期80-92,共13页
This work investigated the absorbed dose to water rate under reference conditions in a Cyberknife VSI system using radiochromic films EBT3 and MD-V3 and three ionization chambers: an Exradin A12 and two FC65P Welh&... This work investigated the absorbed dose to water rate under reference conditions in a Cyberknife VSI system using radiochromic films EBT3 and MD-V3 and three ionization chambers: an Exradin A12 and two FC65P Welh&ouml;fer Scanditronix with different serial numbers. The correction factor,, was studied using a Varian iX linac and the Cyberknife system. The measurements in the Varian iX were performed in a 10 × 10 cm2 field, 10 cm depth in liquid water at 90 cm and 70 cm SSD and in a 5.4 × 5.4 cm2 field, 10 cm depth at 70 cm SSD to simulate the Cyberknife conditions. In the Cyberknife system, measurements were performed using ionization chambers and both film types at 70 cm SSD and 10 cm depth in its 6 cm diameter reference field. The results indicate that ?is independent of the dosimeters and the evaluation methods. Maximum differences of 0.22% - 0.55% (combined uncertainties of 1.22% - 1.98%, k = 1) are obtained on ?using Varian iX, whereas discrepancies of 2.08% - 2.09% (combined uncertainties of 1.87% - 2.13%, k = 1) are observed using the Cyberknife system. Given the agreement between detectors and the combined standard uncertainties, the data from Varian iX could be considered the most accurate and consequently a weighted average factor of 0.902 ± 0.006 could be used for the Cyberknife VSI system reference field. Within measurement uncertainties, the absorbed dose rate measured in the Cyberknife VSI system reference field was found to be independent of the dosimeters used. These results suggest that the absorbed dose measured at a point within a given field size should be the same, regardless the dosimeter used, if their dosimetric characteristics are well known. This highlighted the importance of performing dosimetry by controlling all parameters that could affect the dosimeter response. One can conclude that radiochromic film dosimetry can be considered as an appropriate alternative for measuring absorbed dose to water rate. 展开更多
关键词 Small FIELD DOSIMETRY Reference FIELD CYBERKNIFE Gafchromic Films Ionization CHAMBERS Dose RATE EBT3 MD-V3 6 MV X-Rays
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Relevance of Family in Academic Success on Children
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作者 Patricia Martínez Lanz Ana Cristina Losada Fernández +1 位作者 Fabiola Pecchioni Fernández Martha Patricia Hernández Valdez 《Health》 2017年第2期279-288,共10页
The purpose of this study was to analyze the relationship between academic success and functional and dysfunctional families. A non-experimental, cross-sectional, descriptive correlational design was used. A convenien... The purpose of this study was to analyze the relationship between academic success and functional and dysfunctional families. A non-experimental, cross-sectional, descriptive correlational design was used. A convenience sample of 200 children between 6 and 13 years old, primary and junior high school students was conducted (32.3% were female and 67.7% were male). To assess the relationship, a study case of 21 reagents was designed to empty the obtained information from medical review records from a psychopedagogic clinic. Academic success was measured as from the revision of informal tests and standardized tests. Results showed that the population levels of academic success were average. However, a significant relationship between the age of the parents and the level of academic success was found, indicating that these variables are associated with this problem. Besides that, it was found that there is a tendency in children with cognitive, emotional and sensory problems reflected in low academic success. The findings provide information that could be considered for the development of programs of psychopedagogic intervention to treat children with learning disabilities and low academic success. 展开更多
关键词 ACADEMIC SUCCESS Low ACADEMIC SUCCESS Functional FAMILY DYSFUNCTIONAL FAMILY CHILDREN
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Physico-Chemical and Microbiological Analysis of Water of the “Presa De Los Patos” in the Desierto De Los Leones National Park, Mexico
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作者 Luis Raúl Gutiérrez-Lucas Luz María Chávez-Ramírez Leticia Arregui 《Advances in Biological Chemistry》 2017年第2期122-138,共17页
The Desierto de los Leones National Park is a place that features recreational activities for residents and visitors to Mexico City. The Presa de los Patos (Ducks Dam) is one of the many bodies of water that are prese... The Desierto de los Leones National Park is a place that features recreational activities for residents and visitors to Mexico City. The Presa de los Patos (Ducks Dam) is one of the many bodies of water that are present in the park. By means of physico-chemical and microbiological analysis, it was determined that the water of the Presa de los Patos cannot be considered potable. The pH range was between 5.5 - 5.9. The turbidity exceeded the values established in the standards (10.7 - 32.3 Nephelometric Turbidity Units (NTU’s)). Chemical Oxygen Demand (COD) showed that large amounts of oxygen are needed to oxidize organic matter (106 - 450 mg/L). The amount of coliforms and fecal coliforms exceeds the values established by the standards used (total coliforms 98 - 956 Colony Forming Units (CFU’s), fecal coliforms 78 - 807 CFU’s). Five bacterial genera (Escherichia coli, Pseudomona, Klebsiella, Shigella and Salmonella) were isolated and identified. Most of the bacteria isolated were resistant to ampicillin (90%), while 25% were resistant to ciprofloxacin. The water consumption of the Presa de los Patos is a great risk for the habitants and visitors of the park. 展开更多
关键词 WATER PHYSICO-CHEMICAL MICROBIOLOGICAL Antimicrobial Resistance ANTIBIOTICS
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Algorithm for Fast Calculation of Hirzebruch-Jung Continued Fraction Expansions to Coding of Graph Manifolds
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作者 Fernando I. Becerra López Vladimir N. Efremov Alfonso M. Hernández Magdaleno 《Applied Mathematics》 2015年第10期1676-1684,共9页
We present a new algorithm for the fast expansion of rational numbers into continued fractions. This algorithm permits to compute the complete set of integer Euler numbers of the sophisticate tree graph manifolds, whi... We present a new algorithm for the fast expansion of rational numbers into continued fractions. This algorithm permits to compute the complete set of integer Euler numbers of the sophisticate tree graph manifolds, which we used to simulate the coupling constant hierarchy for the universe with five fundamental interactions. Moreover, we can explicitly compute the integer Laplacian block matrix associated with any tree plumbing graph. This matrix coincides up to sign with the integer linking matrix (the main topological invariant) of the graph manifold corresponding to the plumbing graph. The need for a special algorithm appeared during computations of these topological invariants of complicated graph manifolds since there emerged a set of special rational numbers (fractions) with huge numerators and denominators;for these rational numbers, the ordinary methods of expansion in continued fraction became unusable. 展开更多
关键词 Hirzebruch-Jung Continued Fraction Fast Expansion ALGORITHM GRAPH MANIFOLDS
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The Global Warming and the Possible Solution
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作者 José F. Á brego 《Journal of Geoscience and Environment Protection》 2018年第5期118-120,共3页
On this research, I proposed some solutions to diminish the global warming because we are going to precipice and it is necessary to learn some catastrophic experiences on the world. I have proposed: Recycling the exha... On this research, I proposed some solutions to diminish the global warming because we are going to precipice and it is necessary to learn some catastrophic experiences on the world. I have proposed: Recycling the exhaust gases of the cars to the machine in order to produce clean gases, in the industrial factories, to capture the CO2 gas to produce carbon and oxygen, using electromagnetic irradiation from Ultrasonic excitation. It is an economical process because we have a consume of 0.0113 kJ for 500 ml of CO2 gas, and to dissociate the methane gas using a crossed electron molecular beam;and to generate electric energy research more on nuclear fusion using water as fuel and in the depletion of ozone layer, it is necessary to research more for renovating the damages on it. 展开更多
关键词 Depletion of OZONE Layer Recycling of EXHAUST GASES of CARS GREENHOUSE GASES and Ultrasonic Excitation
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Composition of Triacylglycerols in Fats of Cow and Goat Milk Produced in Four Zones of Mexico
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作者 Rey Gutié rrez Tolentino +14 位作者 Salvador Vega y Leó n Mario Noa Pé rez Marta Coronado Herrera Acacia Ramí rez Ayala José Jesús Pé rez González Beatriz Schettino Bermúdez Rutilio Ortiz Salinas Marcela Vazquez Francisca Juan Gabriel Rivera Martí nez 《Food and Nutrition Sciences》 2015年第6期555-561,共7页
The study of the triacylglycerols (TAG) by gas chromatography (GC) using capillary columns is an efficient technique for the determination of some characteristics of quality of fats and oils. The objective of the pres... The study of the triacylglycerols (TAG) by gas chromatography (GC) using capillary columns is an efficient technique for the determination of some characteristics of quality of fats and oils. The objective of the present study was to determine by GC the content of TAG present in fat of cow and goat milk produced in four zones of Mexico. According to criteria established in Mexican Standardization, 25 samples were obtained of 1 L of ultra-pasteurized cow milk (UHT) and 27 and 48 of raw cow and goat milk, respectively. The fat was extracted from all of the milk samples by detergent solution, and was stored at –20℃ until its analysis. The chromatographic conditions made it possible to identify and quantify TAG of 28 to 54 numbers of carbons, which were analyzed under descriptive and inferential statistical techniques. For the cow milk fat, the statistical analyses indicated significant difference (p < 0.05) in the TAG C34, C50 and C52, and for the goat milk fat in the TAG of C36 to C52. No equality of means was found among the TAG of the cow and goat milk fat. This study offers an advance in the characterization of the TAG present in the cow and goat milk fat produced in Mexico. 展开更多
关键词 COW MILK GOAT MILK Mexico Triacylglycerols
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Doping Graphene by Chemical Treatments Using Acid and Basic Substances
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作者 Claudia Bautista-Flores Roberto Ysacc Sato-Berrú D. Mendoza 《Journal of Materials Science and Chemical Engineering》 2015年第10期17-21,共5页
We prepared single-layer graphene films through mechanical exfoliation of Kish graphite and chemical vapor deposition techniques. These samples were treated in nitric acid, sulfuric acid, sodium hydroxide and ammonium... We prepared single-layer graphene films through mechanical exfoliation of Kish graphite and chemical vapor deposition techniques. These samples were treated in nitric acid, sulfuric acid, sodium hydroxide and ammonium hydroxide solutions to induce doping. We used Micro Raman Spectroscopy before and after the chemical functionalization to monitor differences in the Raman spectrum. We found shifting for both G and 2D peaks of graphene and a significant upshifting in samples treated with sulfuric acid, similar to those reported for nitric acid. 展开更多
关键词 GRAPHENE DOPING Ferric NITRATE RAMAN SPECTROSCOPY
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Relationship between Change of Diet and Poverty in Mexico: A Stochastic Analysis
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作者 Fatima Ezzahra Housni Humberto Bracamontes del Toro +3 位作者 Alejandro Macías Virginia Gabriela Aguilera Cervantes Abdessamad Najine Isaí Guízar Mateos 《Food and Nutrition Sciences》 2016年第2期83-89,共7页
Background: In this article, we seek to break the paradigm of traditional estimates (deterministically) to estimate the probability of transition from poverty and diet change in Mexico through a stochastic model while... Background: In this article, we seek to break the paradigm of traditional estimates (deterministically) to estimate the probability of transition from poverty and diet change in Mexico through a stochastic model while providing a comparative study in the time between the diet change and poverty. Methods: A model based on the theory of Markov applied to the different dimensions of poverty and diet type from aggregate data from government agencies was used. Also likely future state changes were estimated and Monte Carlo simulation was used to find a balance between the transition probabilities of the different states. Results: It was shown that there was a high probability of consuming more fat than protein and carbohydrates in Mexico. In the case of poverty, it was found that poverty of patrimony presented the highest probability of change. Estimates for 2030 show as well that the Mexican population will have equal probabilities of state transition to the type of diet and poverty, as long as you consider changing some current values of both consumption and poverty. Conclusions: It was shown that there was indeed a close relationship between poverty of patrimony and an unbalanced diet where the probability of fat intake was high. The stochastic approach had enabled us, in addition to linking poverty and changing diet, to prevent the Mexican population of future scenarios that could be dramatic and, to avoid this situation, alternatives of change of state consumption and poverty had been proposed. 展开更多
关键词 STOCHASTIC Poverty in Mexico Diet Change Probability of Transition
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Scholz’s First Conjecture: A Brief Demonstration
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作者 José M. Sautto +3 位作者 Agustín Santiago Carlos N. Bouza Veró nica Campos 《Applied Mathematics》 2016年第1期70-76,共7页
This paper presents a brief demonstration of Schulz’s first conjecture, which sets the upper and lower limits on the length of the shortest chain of addition. Two methods of the upper limit are demonstrated;the secon... This paper presents a brief demonstration of Schulz’s first conjecture, which sets the upper and lower limits on the length of the shortest chain of addition. Two methods of the upper limit are demonstrated;the second one is based on the algorithm of one of the most popular methods for obtaining addition chains of a number, known as the binary method. 展开更多
关键词 Addition Chain EXPONENTIATION Short Chain Scholz’s Conjecture Binary Method
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Synthesis and Characterization of Bimetallic Gold-Silver Core-Shell Nanoparticles: A Green Approach
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作者 A. Calagua H. Alarcon +1 位作者 F. Paraguay Juan Rodriguez 《Advances in Nanoparticles》 2015年第4期116-121,共6页
Bimetallic gold-silver core-shell nanoparticles were prepared by chemical reduction in aqueous solution, following a method that was friendly to the environment, allowing us to use this for medicinal purposes. Gold na... Bimetallic gold-silver core-shell nanoparticles were prepared by chemical reduction in aqueous solution, following a method that was friendly to the environment, allowing us to use this for medicinal purposes. Gold nanoparticles were synthesized, and silver cations were then reduced on the nanoparticles. Using the optical properties of metallic nanoparticles, surface plasmon resonance was determined by UV-Vis spectroscopy, and the values obtained for gold and silver were approximately 520 nm and 400 nm in wavelength, respectively. The absorption peaks of the surface plasmon band show a clear red-shift due to size effect in the case of the silver surface, and a plasmon coupling effect, in the case of gold. To obtain a better understanding of the coating conditions, high resolution transmission electron microscopy was used. The average hydrodynamic size and the size distribution of the synthesized nanoparticles were obtained by dynamic light scattering. The development of this process, which is benign for the environment, opens the possibility for many applications in the areas of renewable energy, medicine and biology. 展开更多
关键词 Nanoparticles BIMETALLIC CORE-SHELL GOLD SILVER Au/Ag
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Fighting Poor Quality Medicines: Development, Transfer and Validation of Generic HPLC Methods for Analyzing Two WHO Recommended Antimalarial Tablets
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作者 Jérémie Kindenge Mbinze Achille Yemoa +7 位作者 Pierre Lebrun Pierre-Yves Sacré Védaste Habyalimana Nicodème Kalenda André Bigot Eugène Atindehou Philippe Hubert Roland Djang’eing’a Marini 《American Journal of Analytical Chemistry》 2015年第2期127-144,共18页
As serious but neglected public health problems, poor quality medicines, i.e. for antimalarial medicines, urged to be fought. One of the approaches is to consider the analytical chemistry and separative techniques. In... As serious but neglected public health problems, poor quality medicines, i.e. for antimalarial medicines, urged to be fought. One of the approaches is to consider the analytical chemistry and separative techniques. In this study, a generic liquid chromatographic method was firstly developed for the purpose of screening 8 antimalarial active ingredients, namely amodiaquine (AQ), piperaquine (PPQ), sulfalene (SL), pyrimethamine (PM), lumefantrine (LF), artesunate (AS), artemether (AM) and dihydroartemisinine (DHA) by applying DoE/DS optimization strategy. Since the method was not totally satisfying in terms of peak separation, further experiments were undergone applying the same development strategy while splitting the 8 ingredients into five groups. Excellent prediction was observed prior to correlation between retention times of predicted and observed separation conditions. Then, a successful geometric transfer was realized to reduce the analysis time focusing on the simultaneous quantification of two WHO’s recommended ACTs in anti-malarial fixed-dose combination (AM-LF and AS-AQ) in tablets. The optimal separation was achieved using an isocratic elution of methanol-ammonium formate buffer (pH 2.8;10 mM) (82.5:17.5, v/v) at 0.6 ml/min through a C18 column (100 mm × 3.5 mm, 3.5 μm) thermostated at 25℃. After a successful validation stage based on the total error approach, the method was applied to determine the content of AM/LF or AS/AQ in seven brands of antimalarial tablets currently marketed in West, Central and East Africa. Satisfying results were obtained compared to the claimed contents. 展开更多
关键词 ANTIMALARIAL ACT Simultaneous Determination POOR QUALITY Substances DESIGN of Experiments DESIGN Space Method TRANSFER Accuracy Profile
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Characterization of Two Different Stumps of <i>Spirulina platensis</i>Drying: Assessment of Water Transport Coefficient
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作者 Eloi Salmwendé Tiendrebeogo +6 位作者 Alfa Oumar Dissa Fabien Cherblanc Issakha Youm Jean-Claude Bé net Aboubacar Compaoré Jean Koulidiati 《Food and Nutrition Sciences》 2015年第15期1437-1449,共13页
The sorption behaviour and water transport mechanisms inside Spirulina platensis samples were experimentally analysed during isothermal drying at 25℃ and 50℃. Two different products grown in semi-industrial farms fr... The sorption behaviour and water transport mechanisms inside Spirulina platensis samples were experimentally analysed during isothermal drying at 25℃ and 50℃. Two different products grown in semi-industrial farms from Burkina Faso and France with initial water contents respectively of the range from 2.73 kg w /kg dm to 3.12 kg w /kg dm were characterized. A novel procedure has been developed to determine the water content profiles inside samples during isothermal drying. At both temperatures, experimental results underlined that the physical properties of Spirulina are not sensitive to the geographical origin, Burkina-Faso or France. To keep Spirulina at an water activity below 0.6 in order to preserve it from micro-organisms development, sorption isotherm curves show that a sufficient requirement is to lower the water content until an upper limit of w = 0.075 db. The evolution of water transport coefficient as a function of water content highlights a monotonous exponential dependence with a transport coefficient ranging from 1.70 × 10–10 to 94 × 10–10 m2/s. The contribution of solid phase shrinkage to the transport of water is negligible for the last drying steps. 展开更多
关键词 i>Spirulina PLATENSIS Isotherm Desorption Stump WATER Content WATER Transport COEFFICIENT
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Mapping and Characterization of Agricultural Systems from Time Series of Normalized Difference Vegetation Index (NDVI) in the Northeast Area of Tadla, Morocco
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作者 Didi Salahddine Fatima Ezzahra Housni +4 位作者 Abdessamad Najine Amina Wafik Mohamed Aadraoui Fatima Zahra Hafiane Humberto Bracamontes del Toro 《Natural Resources》 2017年第1期24-30,共7页
Introduction: Agriculture is the focus of sustainable development and food security in Morocco, contributing 14% to the national economy and its socio-economic impact depends on agro-climatic conditions and the availa... Introduction: Agriculture is the focus of sustainable development and food security in Morocco, contributing 14% to the national economy and its socio-economic impact depends on agro-climatic conditions and the availability of water resources. The objective of this work is to demonstrate that agriculture in Morocco, and especially in the Tadla region, is distributed according to the availability of underground water. Method: This work was carried out in the transition zone between the phosphate plateau and the plain of Tadla, a site of more than 124,000 ha. To achieve the objectives set, we used Landsat-8 OLI (Operational Land Imager) data sharpened to 15 m. The Support Vector Machine (SVM) classifications were applied to the 10-period Normalized Difference Vegetation Index (NDVI) series. Results: It is shown that agriculture in Morocco is highly dependent on irrigation. In the classified map, it can be observed that the southern region, a zone with a semi-arid climate, which generally relies on irrigation, is very developed in agriculture, whereas in the north most of the soil is bared with cereals that mainly depend on rainfall. Conclusion: The possible water shortage in the region puts food availability in Morocco at risk of inadequacy. Food security depends on the availability of water, a natural resource at risk of extinction. Therefore, strategies to reduce the risk of agricultural drought must be at the forefront of Moroccan policies. 展开更多
关键词 Water AVAILABILITY Landsat-8 OLI CROP MAPPING PLAIN de Tadla Morocco
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Mexican Sign Language Recognition Using Jacobi-Fourier Moments
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作者 Francisco Solís Carina Toxqui David Martínez 《Engineering(科研)》 2015年第10期700-705,共6页
The present work introduces a system for recognizing static signs in Mexican Sign Language (MSL) using Jacobi-Fourier Moments (JFMs) and Artificial Neural Networks (ANN). The original color images of static signs are ... The present work introduces a system for recognizing static signs in Mexican Sign Language (MSL) using Jacobi-Fourier Moments (JFMs) and Artificial Neural Networks (ANN). The original color images of static signs are cropped, segmented and converted to grayscale. Then to reduce computational costs 64 JFMs were calculated to represent each image. The JFMs are sorted to select a subset that improves recognition according to a metric proposed by us based on a ratio between dispersion measures. Using WEKA software to test a Multilayer-Perceptron with this subset of JFMs reached 95% of recognition rate. 展开更多
关键词 MEXICAN SIGN LANGUAGE Jacobi-Fourier MOMENTS Digital Image Processing
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