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Synthesis of coral-like structures of Pr-Yb co-doped YIG: Structural,optical, magnetic and antimicrobial properties

Journal of Rare Earths 2024年第3期42卷 543-554,I0004页

作者： A.Fernandez Francisca P.Araujo Y.Guerra S.Castro-Lopes J.Matilla-Arias Idglan S.de Lima Edson C.Silva-Filho Josy A.Osajima F.Guerrero R.Pena-garcia Federal University of Piau Graduate Program in Materials Science and EngineeringTeresinaPIBrazil Federal Rural University of Pernambuco Academic Unit of Cabo de Santo AgostinhoCabo de Santo AgostinhoPEBrazil Federal University of Piaui Department of PhysicTeresinaPBrazil Federal University of Pernambuco Graduate Program in Materials ScienceRecifePEBrazil University of Granma Departmentof Basic Sciences and Applied InformaticsFaculty of Technical SciencesBayamoCuba Federal University of Amazonas Department of PhysicManausAMBrazil Federal University of Pernambuco Department of PhysicRecifePEBrazil

Coral-like structures of the Y_(3-x)Pr_(x)Fe_(5-y)Yb_(y)O_(12),(0.00 ≤ x ≤ 0.04, 0.00 ≤ y ≤ 0.02) compound were synthesized using the sol-gel method. Structural investigation certified the YIG cubic crystal structure formation, without any secondary phase. It is shown that, the relatively large ionic radius of the dopant cations results in an expansion of the lattice parameter, variations in the Iona-O-Iondangle, Iona-O,Iond-O and Ionc-O bond distances and decrease in the average crystallite size. Fourier transform infrared(FTIR) and Raman measurements are essential to testify the single-phase formation of YIG crystal structure and are observed changes in the stretching and vibrational modes, respectively. The morphological study, energy dispersive spectroscopy(EDS) spectra and textural properties show corallike structures, peaks associated with Pr^(3+) and Yb^(3+) atoms and the effect of dopants on surface area,diameter, and pore volume, respectively. The optical analysis from diffuse reflectance spectra witnessed an increase in the optical gap band, a decrease in Urbach energy and blue shift in the charge transfer,correlated with the expansion of the unit cell due to the dopant's insertion in the YIG structure. A typical ferrimagnetic behavior is exhibited by the Y_(3-x)Pr_(x)Fe_(5-y)Yb_(y)O_(12)compound. The saturation magnetization(M_(s)), cubic anisotropy constant(K_(1)) and coercive field(H_(c)) increase with the Pr^(3+)cations content, as consequence of their magnetic nature and distribution around of Fe^(3+)ions due to the coexistence with the Yb^(3+). Finally, for the first time, antibacterial tests by mean of the direct contact method were performed for YIG co-doped with Pr^(3+)and Yb^(3+)and it is shown that, relatively high dosages of Pr^(3+) cations favored the activity against S. aureus, therefore, a new biological property for YIG doped with rare earths is presented.

关键词： Yttrium iron garnet(YIG) Coral-like structures Rare earths Band gap energy Magnetic properties Antimicrobial properties

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Development of Extraction and Detection Method for a Chemotherapeutic Drug with Phenytoin in Biological Samples

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Advances in Biological Chemistry 2024年第4期14卷 103-110页

作者： Michael Arnot Nicolas Brice Adan garcia Victor Lomeli My Phuong Vu Karno Ng Department of Chemistry & Biochemistry California State University San Marcos San Marcos CA U.S.A.

Dexamethasone is classified as a corticosteroid and is commonly used among cancer patients to decrease the amount of swelling around the tumor. Among patients with cancer, in particular brain tumors, seizures can become a daily routine in their everyday lives. To counteract the seizures, an antiepileptic drug such as phenytoin is administered to act as an anticonvulsant. Phenytoin and dexamethasone are frequently administrated concurrently to brain cancer patients. A previous study has shown that phenytoin serum concentration decreases when administrated concurrently with dexamethasone. Thus, it is important to monitor the concentration of these two drugs in biological samples to ensure that the proper dosages are administrated to the patients. This study aims to develop an effective extraction and detection method for dexamethasone and phenytoin. A reverse-phase high-performance liquid chromatography (HPLC) method with UV/Vis detection has been developed to separate phenytoin and dexamethasone at 219 nm and 241 nm respectively from urine samples. The mobile phase consists of a mixture of 0.01 M KH2PO4, acetonitrile, and methanol adjusted to pH 5.6 (48:32:20) and is pumped at a flow rate of 1.0 mL/min. Calibration curves were prepared for phenytoin and dexamethasone (r2 > 0.99). An efficient solid-phase extraction (SPE) method for the extraction of dexamethasone and phenytoin from urine samples was developed with the use of C-18 cartridges. The percent recovery for phenytoin and dexamethasone is 95.4% (RSD = 1.15%) and 81.1% (RSD = 3.56%) respectively.

关键词： Dexamethasone Phenytoin Cancer Drug Interaction Solid Phase Extraction

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寻文化之根,叹汉语之美

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初中生 2024年第11期 4-17页

作者： Juan-Diego garcia 不详

主题语境:人与社会——人文历史,文化传承仓颉观天地万物而造字。一片甲骨,一些符号,让我们触摸到汉字的源头。正因为有了文字,我们才能从中窥见古人的智慧,感受中华民族几千年来的灿烂文化。联合国新闻部将中国二十四节气之“谷雨”(4... 详细信息

主题语境:人与社会——人文历史,文化传承仓颉观天地万物而造字。一片甲骨,一些符号,让我们触摸到汉字的源头。正因为有了文字,我们才能从中窥见古人的智慧,感受中华民族几千年来的灿烂文化。联合国新闻部将中国二十四节气之“谷雨”(4月20日)这一天定为联合国中文日。如今,越来越多来自世界各地的人们,为一部《论语》传递的“谦恭礼让”而折服,被汉语蕴藏的文化魅力所吸引。

关键词：文化传承二十四节气文化魅力天地万物汉语之美人文历史文化之根联合国

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Early anticoagulation in patients with stroke and atrial fibrillation is associated with fewer ischaemic lesions at 1 month: the ATTUNE study

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Stroke & Vascular Neurology 2024年第1期9卷 30-37,I0034页

作者： Angelos Sharobeam Longting Lin Christina Lam Carlos garcia-Esperon Yash Gawarikar Ronak Patel Matthew Lee-Archer Andrew Wong Michael Roizman Amanda Gilligan Andrew Lee Kee Meng Tan Susan Day Christopher Levi Stephen M Davis Mark Parsons Bernard Yan Melbourne Brain Centre at Royal Melbourne Hospital ParkvilleVictoriaAustralia University of New South Wales South Western Sydney Clinical School LiverpoolNew South WalesAustralia Department of Neurology John Hunter HospitalNewcastleNew South WalesAustralia Department of Neurology Calvary Public HospitalCanberraAustralian Capital TerritoryAustralia Department of Neurology Northern Hospital EppingEppingVictoriaAustralia Department of Neurology Royal Brisbane and Women's HospitalHerstonQueenslandAustralia The University of Queensland School of Medicine HerstonQueenslandAustralia Neurosciences Clinical Institute Epworth HealthcareRichmondVirginiaAustralia Department of Neurology Austin HealthUniversity of MelbourneHeidelbergVictoriaAustralia Flinders University College of Medicine and Public Health AdelaideSouth AustraliaAustralia Department of Neurology Gold Coast University HospitalSouthportQueenslandAustralia The University of Sydney Northern Clinical School St LeonardsNew South WalesAustralia Department of Neurology and Neurophysiology Liverpool HospitalLiverpoolNew South WalesAustralia

Background The optimal time to commence anticoagulation in patients with atrial fibrillation(AF)after ischaemic stroke or transient ischaemic attack(TIA)is unclear,with guidelines differing in recommendations.A limitation of previous studies is the focus on clinically overt stroke,rather than radiologically obvious diffusion-weighted imaging ischaemic *** aimed to quantify silent ischaemic lesions and haemorrhages on MRI at 1month in patients commenced on early(5mL,regardless of anticoagulation *** Commencing anticoagulation<4days after stroke or TIA is associated with fewer ischaemic lesions at 1month in AF *** is no increased rate of haemorrhage with early *** results suggest that early anticoagulation after mild-to-moderate acute ischaemic stroke associated w

关键词： patients lesions ischaemic

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美食传说,有味还有道

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初中生 2024年第18期 4-13页

作者： Paul Yee Wenxi garcia 不详

主题语境:人与社会——民间传说,饮食文化。一位加拿大华商儿童文学作家创作的《中国神话盛宴》(Chinese Fairy Tale Feasts)一书中,讲述了20多个跟中国美食有关的民间传说。拉面、虾仁鲜饺、米饭,这些我们习以为常的食物背后,原来还有... 详细信息

主题语境:人与社会——民间传说,饮食文化。一位加拿大华商儿童文学作家创作的《中国神话盛宴》(Chinese Fairy Tale Feasts)一书中,讲述了20多个跟中国美食有关的民间传说。拉面、虾仁鲜饺、米饭,这些我们习以为常的食物背后,原来还有一些听起来不可思议的故事。事实上,神奇的事情往往发生在最虔诚、最善良的人身上。

关键词：饮食文化儿童文学作家民间传说美食拉面虾仁米饭

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Changes in calcium accumulation and utilization efficiency and their impact on recycling,immobilization,and export across the oil palm cycle

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Oil Crop Science 2024年第3期9卷 143-150页

作者： Ismael de Jesus Matos Viégas Luma Castro de Souza Eric Victor de Oliveira Ferreira Milton garcia Costa Glauco André dos Santos Nogueira Vitor Resende do Nascimento Candido Ferreira de Oliveira Neto Capanema Campus Federal Rural University of the Amazon(UFRA)Av.Barao de CapanemaCaixa D'agua5514-6434ParaBrazil Center of Agricultural and Environmental Sciences Federal University of Maranhao(UFMA)ChapadinhaBR-222km 04SNBoa Vista65500000MaranhaoBrazilc Capitao Poço Campus Federal Rural University of the Amazon(UFRA)Tv.Pau AmareloS/n-Vila Nova68650-000Capitao PoçoParaBrazil Department of Soil Science Sao Paulo State University(Unesp)School of Agricultural and Veterinarian SciencesJaboticabalVia de Acesso Prof.Paulo Donato CastelaneCastellane-S/N-Vila Industrial14884-900Sao PauloBrazil Institute of Agricultural Sciences(ICA) Federal Rural University of the Amazon(UFRA)Estr.Principal da Ufra2150Curio-Utinga66077-580BelemParaBrazil

Effective calcium(Ca)management is crucial for optimizing oil palm cultivation and enhancing crop *** study aimed to gain insights into the dynamics of Ca concentration,accumulation,exportation,immobilization,and recycling in various oil palm organs relative to plant *** experiment was conducted at the Agropalma enterprise site in the northeastern region of Para State,Brazil,evaluating seven plant age treatments:2,3,4,5,6,7,and 8 years *** a completely randomized design with four *** results demonstrated an age-related increase in Ca concentration in petioles,rachis,arrows,male inflorescences,peduncles,and ***,Ca accumulation exhibited an upward trend in all organs with progressing plant ***,the study revealed an enhanced Ca use efficiency across all plant organs in correlation with the age of oil palm *** findings underscore the dynamic nutritional demands of oil palm,influencing Ca immobilization,cycling,and export throughout its developmental stages.

关键词： Elaeis guineensis Jacq Ca cycling Ca export Ca immobilization Ca use efficiency Plant nutrition Amazon

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Distribution and Relation of Primes with Tesla Numbers 3, 6, and 9

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Journal of Applied Mathematics and Physics 2024年第4期12卷 1021-1027页

作者： Javier Mendoza-Navarrete Huetzin Perez Ismael Ojeda Victor Verdugo Gabriel Luna Sandoval Ricardo Jimenez garcia Jaime Alvarez Departametno de Matemá ticas CBTis 256 DGETI Cabo San Lucas M&#233xico DCI Departamento de Fisica Mé dica Universidad de Guanajuato Leon M&#233xico Divisió n de Ingenieria en Sistemas Computacionales Tecnol&#243gico Nacional de M&#233xico ITES Los Cabos Cabo San Lucas M&#233xico Departamento de Ingenieria Industrial en Manufactura Universidad Estatal de Sonora Navojoa M&#233xico Departamento de Elé ctrica-Electr&#243nica Tecnol&#243gico Nacional de M&#233xico Campus Mexicali Mexicali M&#233xico Guanajuato M&#233xico

This work presents a different approach to twin primes, an approach from the perspective of the Tesla numbers and gives a refresh and new observation of twin primes that could lead us to an answer to the Twin Prime Conjecture problem. We expose a peculiar relation between twin primes and the generation of prime numbers with Tesla numbers. Tesla numbers seem to be present in so many domains like time, vibration and frequency [1], and the space between twin primes is not the exception. Let us say that twin primes are more than just prime numbers plus 2 or minus 2, and Tesla numbers are more involved with twin primes than we think, and hopefully, this approach give us a better understanding of the distribution of the twin pairs.

关键词： Tesla Numbers Prime Number Twin Prime Numbers Twin Pair

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Analysis of Modeling the Influence of Electromagnetic Fields Radiated by Industrial Static Converters and Impacts on Operators Using Maxwell’s Equations

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Open Journal of Applied Sciences 2024年第8期14卷 2320-2350页

作者： Anthony Bassesuka Sandoka Nzao Tuka Biaba Samuel garcia Obed Bitala Arsène Kasereka Kibwana Emmanuel Ndaye Kibuayi ISTA Kinshasa Electrical Engineering Kinshasa Democratic Republic of Congo Doctoral School of ISTA Kinshasa Complementary Master in Science and Technology/Electrical Engineering Electrotechnical Option Kinshasa Democratic Republic of Congo ISTA Kinshasa Doctoral School in Science and Technology Electronics Option Kinshasa Democratic Republic of Congo

The study of Electromagnetic Compatibility is essential to ensure the harmonious operation of electronic equipment in a shared environment. The basic principles of Electromagnetic Compatibility focus on the ability of devices to withstand electromagnetic disturbances and not produce disturbances that could affect other systems. Imperceptible in most work situations, electromagnetic fields can, beyond certain thresholds, have effects on human health. The objective of the present article is focused on the modeling analysis of the influence of geometric parameters of industrial static converters radiated electromagnetic fields using Maxwell’s equations. To do this we used the analytical formalism for calculating the electromagnetic field emitted by a filiform conductor, to model the electromagnetic radiation of this device in the spatio-temporal domain. The interactions of electromagnetic waves with human bodies are complex and depend on several factors linked to the characteristics of the incident wave. To model these interactions, we implemented the physical laws of electromagnetic wave propagation based on Maxwell’s and bio-heat equations to obtain consistent results. These obtained models allowed us to evaluate the spatial profile of induced current and temperature of biological tissue during exposure to electromagnetic waves generated by this system. The simulation 2D results obtained from computer tools show that the temperature variation and current induced by the electromagnetic field can have a very significant influence on the life of biological tissue. The paper provides a comprehensive analysis using advanced mathematical models to evaluate the influence of electromagnetic fields. The findings have direct implications for workplace safety, potentially influencing standards and regulations concerning electromagnetic exposure in industrial settings.

关键词： Modeling Electromagnetic Field Power Converters Geometric Parameters Biological Tissue Maxwell Equation Bio-Heat Equation Thermal Model

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Determinants of Satisfaction at Work and Its Reflections on Performance

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Chinese Business Review 2024年第1期23卷 24-36页

作者： Giovani Luiz garcia Costantini Everton Anger Cavalheiro Larissa Medianeira Bolzan Alejandro Martins Rodrigues Luíza Roloff Falck Federal University of Pelotas PelotasBrazil

This study examines the relationship between job satisfaction and performance,investigating personality traits and satisfaction aspects among employees of a Federal Higher Education Institution.A questionnaire was administered to 658 participants,using structural equation modeling for *** highlighted that challenging work,neuroticism,and self-esteem significantly influenced overall workplace satisfaction,while general satisfaction,self-efficacy,and lack of attention were key determinants of work *** emphasizes the importance for managers to prioritize factors enhancing employee satisfaction,as it positively correlates with job performance.

关键词： satisfaction at work work performance personality traits facets of job satisfaction Federal Higher Education Institution

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The Nikola Tesla Constant and Its Relation to the Circumference Inscribed in a Square

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Journal of Applied Mathematics and Physics 2024年第1期12卷 277-283页

作者： Javier Mendoza Navarrete José Ismael Ojeda Campaña Huetzin Perez Gabriel Luna-Sandoval Victor Verdugo Ricardo Jiménez garcia Departamento de Matemáticas CBTis 256 DGETI Cabo San Lucas México División de Ingeniería en Sistemas Computacionales Tecnológico Nacional de México/ITES de Los Cabos Cabo San Lucas México DCI Departamento de Física Médica Universidad de Guanajuato León México Departamento de Ingeniería Industrial en Manufactura Universidad Estatal de Sonora Navojoa México Departamento de Eléctrica-Electrónica Tecnológico Nacional de México Campus Mexicali Mexicali México

This research work relates the surface of a square and the area circumscribed by a circle, resulting in a value called Nikola Tesla constant. This constant starts with the calculation of the areas of the square and the inscribed circle, giving a ratio of 9/40 and from which a residual area of the area proportions of the geometric figures described is obtained. Plotting smooth curves, particularly those in round shapes, can be represented efficiently with the use of Nikola Tesla constant, reducing complex mathematical calculus.

关键词： Tesla Numbers Prime Number Circle Binary Area

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