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Application of a validated HPLC-PDA method for the determination of melatonin content and its release from poly(lactic acid)nanoparticles

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Journal of Pharmaceutical Analysis 2017年第6期7卷 388-393页

作者： Leiziani Gnatkowski Martins Najeh Maissar Khalil Rubiana mara Mainardes Department of Pharmacy Universidade Estadual do Centro-Oeste/UNICENTRORua Simeao Camargo Varela de Sd 0385040-080 GuarapuavaPRBrazil

Melatonin is a natural hormone and with the advancement of age its production declines and thereby may result in some neurological disorders. Exogenous administration of melatonin has been suggested as a neuroprotective agent. Due to its low oral bioavailability, the loading of melatonin in polymeric nanoparticles could be an important tool to effectively use exogenous melatonin. The quantification of the incorporated drug within polymeric nanoparticles is an important step in nanoparticles characterization. An analytical method using high performance liquid chromatography equipped with photodiode array detector （HPLC-PDA） was developed and validated for melatonin determination in poly （lactic acid） nanoparticles obtained by a single emulsion-solvent evaporation technique. The melatonin in vitro release profile also was determined by the HPLC method. Mobile phase consisted of acetonitrile： water （65：35, v/v） pumped at a flow rate of 0.9 mL/min, in the isocratic mode and PDA detector was set at 220 nm. The method was validated in terms of the selectivity, linearity, precision, accuracy, robustness, limits of detection and quantification. Analytical curve was linear over the concentration range of 10-100 ~tg/mL, and limits of detection and quantification were 25.9 ng/mL and 78.7 ng/mL, respectively. The mean recovery for melatonin was 100.47% （RSD = 1.25%, n = 9）. In the intra- and inter- assay, the coefficient of variation was less than 2%. Robustness was proved performing changes in mobile phase, column temperature and flow rate. The method was suitable for the determination of melatonin encapsulation efficiency in poly（lactic acid） nanopartieles and for the evaluation of melatonin in vitro release profile.

关键词： High-performance liquid chromatography Validation Melatonin Polymeric nanoparticles

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Maintaining nano-lamellar microstructure in friction stir welding (FSW) of accumulative roll bonded (ARB) Cu-Nb nano-lamellar composites (NLC)

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Journal of Materials Science & Technology 2018年第1期34卷 92-101页

作者： Judy Schneider Josef Cobb John S.Carpenter Nathan A.mara Department of Mechanical & Aerospace Engineering University of Alabama in Huntsville Department of Mechanical Engineering Mississippi State University Materials Science and Technologies Division Los Alamos National Laboratory Center for Integrated Nanotechnologies and the Institute for Materials ScienceLos Alamos National Laboratory

Accumulative roll bonded （ARB） Copper Niobium （Cu-Nb） nano-lamellar composite （NLC） panels were friction stir welded （FSWed） to evaluate the ability to join panels while retaining the nano-lamellar structure. During a single pass of the friction stir welding （FSW） process, the nano-lamellar structure of the parent material （PM） was retained but was observed to fragment into equiaxed grains during the second pass. FSW has been modeled as a severe deformation process in which the material is subjected to an instantaneous high shear strain rate followed by extreme shear strains. The loss of the nano-lamellar layers was attributed to the increased strain and longer time at temperature resulting from the second pass of the FSW process. Kinematic modeling was used to predict the global average shear strain and shear strain rates experienced by the ARB material during the FSW process. The results of this study indicate that through careful selection of FSW parameters, the nano-lamellar structure and its associated higher strength can be maintained using FSW to join ARB NLC panels.

关键词： Nano-lamellar materials Accumulative roll bonded Cu-Nb FSW Solid state joining

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Coconut oil:what do we really know about it so far?

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Food Quality and Safety 2019年第2期3卷 61-72页

作者： Renan da Silva Lima Jane mara Block Department of Food Science and Technology Federal University of Santa CatarinaFlorianópolisBrazil

In recent years,coconut oil has emerged as a potential‘miracle’*** media vehicles and health specialists assure that this fat is capable of promoting health benefits,such as weight reduction,cholesterol lowering,prevention of cardiovascular diseases,and anti-inflammatory effect,among *** claims are used to market the product and boost its sales by coconut oil ***,governmental regulatory agencies in many countries are still sceptical about the benefits obtained by the consumption of coconut oil due to its high-saturated fatty acid *** light of such controversy,this review focused on analysing the published literature on the alleged health claims,in order to investigate if there is enough scientific evidence to support *** was verified that the metabolism of lauric acid,the major fatty acid in coconut oil,remains *** studies reported that the product was not efficient in weight ***,it has been reported that the consumption of coconut oil increased low-density lipoprotein cholesterol,consequently increasing the risk of cardiovascular *** general,the studies present conflicting results and there is a lack of long-term human-based clinical ***,as a saturated fat,coconut oil should be consumed with moderation and the health allegations should not be used to market the product,once they are not scientifically proven so far.

关键词： lauric acid saturated fatty acids medium-chain triglycerides LDL cholesterol cardiovascular diseases

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Hepatocellular carcinoma and food contamination: Ochratoxin A as a great prompter

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World Journal of Gastroenterology 2013年第24期19卷 3723-3725页

作者： Raphael JF Felizardo Niels OS Cmara Division of Nephrology Department of Medicine Federal University of Sao PauloSao Paulo CEP 05508-900 Brazil Department of Immunology Institute of Biomedical Sciences University of S o PauloSao Paulo CEP 05508-900 Brazil

Ochratoxin A (OTA) is a secondary metabolite of Asper-gillus and Penicillium, microorganisms that can be haz-ardous to health when present as food contaminants. OTA is a potent member of a group of mycotoxins. Prolonged exposure to mycotoxins in the diet is related to cancer, among other diseases. Hepatocellular car-cinoma (HCC) accounts for 70%-90% of primary liver cancers and is the third leading cause of cancer-related deaths worldwide. In a recent study, Ibrahim et al proposed a correlation between the incidence of HCC and contamination with OTA. Analysis of OTA in serum samples showed that HCC patients had the highest incidence of OTA of the subjects examined (5-fold higher than that of the control group). OTA levels were significantly increased in HCC patients. This study demonstrates that chronic exposure to high levels of OTA may be associated with a high risk of liver cancer development. Future epidemiologic studies of HCC should focus on good practices in food preparation, food storage and the consumption of OTA-containing foods.

关键词： Ochratoxin A Mycotoxin Food contamination Hepatocellular carcinoma Liver cancer Egypt

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Enhanced consolidation efficacy and durability of highly porous calcareous building stones enabled by nanosilica-based treatments

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Science China(Technological Sciences) 2023年第8期66卷 2197-2212页

作者： CAO YiJian CAMAITI mara ENDRIZZI Monica FORTI Giorgio VERGANI Ernesta FORTI Ilaria Institute of Culture and Heritage Northwestern Polytechnical UniversityXi’an 710072China CNR-Institute of Geosciences and Earth Resources Florence 50121Italy Monica Endrizzi Conservative Art Restoration Casale sul Sile-Treviso 31032Italy Forti Architecture Studio Verona 37121Italy Ernesta Vergani Restoration of Works of Art Volpago del Montello-Treviso 31040Italy Ernesta Vergani Restoration of Works of Art Cannaregio 4056Venezia 30121Italy UniversitàIUAV di Venezia Venezia 30135Italy

Outdoor building stones are suffering from serious *** restore internal cohesion and to alleviate the disintegration of decayed stones,consolidation treatment is necessary and *** to date,no fully satisfactory consolidation agent and its application methodology are available,mainly due to the limited penetration depth of consolidants,low compatibility,or poor durability in environmental ***,in this study,aiming to design an effective and enduring method for the consolidation of highly porous calcareous stones,nanosilica-based consolidation treatments were tested and compared with traditional compounds(tetraethoxysilane,alkylalkoxysilane,barium hydroxide).In order to evaluate their performance and compatibility,a series of standard tests,including the Drilling Resistance Measurement System(DRMS)test,surface color measurement,vapor diffusivity measurement,and peeling test,were carried ***,the penetration depth and distribution profiles of consolidants were estimated by exploiting elemental raster scanning of SEM-EDS analysis performed throughout the thickness of *** importantly,by employing a climatic chamber,the artificial ageing test was also conducted by simulating harsh atmospheric *** accelerated ageing,the performance of all consolidants was assessed *** demonstrated that the application of nanosilica(<10 nm in dimension)by cellulose poultice,followed by adding tetraethoxysilane with the classical method“wet on wet”,is the best consolidation approach,in terms of in-depth consolidation efficacy,compatibility with the stone substrate,surface cohesion strength and performance durability in environmental ***,the treated surface is not hydrophobic,which allows further grouting and adhesion operations usually required for the restoration of historic buildings.

关键词： stone consolidation nanosilica tetraethoxysilane penetration depth durability

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Erosive wear properties of ZA-27 alloy-based nanocomposites: Influence of type, amount, and size of nanoparticle reinforcements

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Friction 2019年第4期7卷 340-350页

作者： Aleksandar VENCL Ilija BOBIC Biljana BOBIC Kristina JAKIMOVSKA Petr SVOBODA mara KANDEVA Faculty of Mechanical Engineering University of BelgradeKraljice Marije 16Belgrade 11120Serbia Institute of Nuclear Sciences'Vinca' University of BelgradeMike Petrovica Alasa 12-14Belgrade 11001Serbia Institute of Chemistry Technology and MetallurgyUniversity of BelgradeNjegoseva 12Belgrade 11000Serbia Faculty of Mechanical Engineering in Skopje Ss.Cyril and Methodius UniversityKarposh II bbSkopje 1000Macedonia Faculty of Mechanical Engineering Brno University of TechnologyTechnicka2896/2Brno 61669Czech Republic Faculty of Industrial Technology Technical University of Sofia8 Kliment Ohridski BlvdSofia 1000Bulgaria

Metal matrix nanocomposites(MMnCs)comprise a metal matrix filled with nanosized reinforcements with physical and mechanical properties that are very different from those of the *** ZA-27 alloy-based nanocomposites,the metal matrix provides ductility and toughness,while usually used ceramic reinforcements give high strength and *** ZA-27 alloy-based nanocomposites,reinforced with different types(Si C and Al2O3),amounts(0.2 wt.%,0.3 wt.%,and 0.5 wt.%)and sizes(25 nm,50 nm,and 100 nm)of nanoparticles were produced through the compocasting process with mechanical alloying pre-processing(ball milling).It was previously shown that the presence of nanoparticles in ZA-27 alloy-based nanocomposites led to the formation of a finer structure in the nanocomposites matrix and an improvement in the basic mechanical properties(hardness and compressive yield strength)through the enhanced dislocation density strengthening *** particle erosive wear testing demonstrated that these improvements were followed with an increase in the erosive wear resistance of tested nanocomposites,as ***,by analyzing the influences of type,amount,and size of nanoparticles on the erosive wear resistance of nanocomposites,it was demonstrated that there is an optimal amount of nanoparticles,which in our case is 0.3 wt.%,and that the presence of SiC nanoparticles and smaller nanoparticles in nanocomposites had more beneficial influence on erosive wear resistance.

关键词： ZA-27 alloy nanocomposites nanoparticles compocasting fractography erosive wear

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中国特色农业农村现代化的历史方位与发展战略

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当代经济管理 2024年第4期46卷 54-62页

作者：农业农村部规划设计研究院课题组张辉农业农村部规划设计研究院北京100125

农业农村现代化是国家现代化的重要标志。站在新的历史方位上,文章厘清发展基础及面临形势,明晰战略重点,并提出政策建议。现阶段,我国农业农村现代化具备了向更高层级迈进的条件,但与发达国家相比,还普遍存在粮食丰而不够盈、农业大而... 详细信息

农业农村现代化是国家现代化的重要标志。站在新的历史方位上,文章厘清发展基础及面临形势,明晰战略重点,并提出政策建议。现阶段,我国农业农村现代化具备了向更高层级迈进的条件,但与发达国家相比,还普遍存在粮食丰而不够盈、农业大而不够强等问题挑战。加快中国特色的农业农村现代化建设,必须加强粮食安全强基战略、乡村产业强链战略、乡村生态低碳转型战略、和美乡村建设战略、农耕文明赓续战略、农民收入跃升战略、农业科技自立自强战略、农村改革赋能战略,并建立健全五级书记抓乡村振兴督导机制、打通各类资本进入农业农村渠道、健全城乡融合发展的体制机制、加强科技创新引领现代农业。

关键词：农业农村现代化历史方位发展战略

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New Clues that May Link Osteoporosis to the Circulating Lipid Profile

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Bone Research 2013年第3期1卷 260-266页

作者： Catalina Poiana Valentin Radoi mara Carsote John P. Bilezikian "C. I. Parhon" National Institute of Endocrinology Bucharest Bucharest Romania University of Medicine and Pharmacy"Carol Davila" Bucharest Bucharest Romania College of Physicians and Surgeons Columbia UniversityNew York NY USA

Bone Mineral Density （BMD） is a gold standard for the diagnosis of osteoporosis and is also important in the assessment of fracture risk. Other risk factors have been identified that together make up fracture risk assessment tools such as FRAX. Another potential factor, circulating lipids, has been suggested because of reports linking statins to fracture risk reduction. We analyzed the lipid profile in a cohort of women diagnosed with postmenopausal osteoporosis based on bone density determination： 610 women with osteo- porosis （mean lumbar spine T-score -3.16±0.81, mean yrs. since menopause 15.79±8.9） were grouped according to age at evaluation （〈 50 years, 51-60 years, 61-70 years, 〉 70 years）, the presence/absence of a history of a fragility fracture, statin and/or antiresorptive drug use. There was no correlation between BMD and Body Mass Index （BMI： P〉0.05, r2〈0.02）. However, when BMD was correlated with both BMI and the lipid profile （Triglycerides, Cholesterol, LDLc, HDLc）, significant correlations were found in 5 cohorts： 51-60 years with fractures （n=61, r2=0.14, P〈0.01）, 61-70 years （n=201, r2=0.09, P〈0.01） with fractures （n=88, r2=0.14, P〈0.01） or without fractures （n=113, r2=0.24, P=0.02） and over 70 years （n=247, r2=0.11, P〈0.01）.

关键词： osteoporosis bone mineral density lipid cholesterol triglycerides HDL-cholesterol

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Food quality,food-borne diseases,and food safety in the Brazilian food industry

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Food Quality and Safety 2017年第1期1卷 13-27页

作者： Maria Manuela Camino Feltes Adriana Pavesi Arisseto-Bragotto Jane mara Block Department of Food Science and Technology Federal University of Santa CatarinaRod.Admar GonzagaItacorubiFlorianópolisBrazil Department of Food Science State University of CampinasRua Monteiro LobatoSão PauloBrazil

INTRODUCTION:In the recent decades,a global effort from food suppliers,industries,and governments has ensured that food production would meet the high quality required by the sanitary authorities,minimizing public health implications and economic losses caused by food-borne ***:Several programmes and initiatives have been developed worldwide both by government agencies and the private sector to achieve this ***-borne diseases,caused by pathogens,natural toxins,and chemical contaminants,remain a global public health challenge,since new threats are continuously emerging while others are being ***,in many countries,the consumption of food prepared outside the home increases the exposure to the risks posed by poor hygiene in food *** this context,a reliable sanitary surveillance system is urgently needed to identify potential hazards,conduct risk analysis,and control food-borne diseases outbreaks *** SAFETY POLICIES AND REGULATORY FRAMEWORKS:Brazil national agencies are tasked with controlling the hazards in the food chain by means of federal regulations based on a set of global sanitary authorities’***:The occurrence of food-borne diseases,control measures,policies,and regulatory frameworks in Brazil drawn to ensure the quality and safety of food are presented in this paper.

关键词： Brazilian food regulation Food policies Public health Food safety

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Food quality and safety progress in the Brazilian food and beverage industry:chemical hazards

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Food Quality and Safety 2017年第2期1卷 117-129页

作者： Adriana Pavesi Arisseto-Bragotto Maria Manuela Camino Feltes Jane mara Block Department of Food Science State University of Campinas-UNICAMPRua Monteiro LobatoCampinas-SPBrazil Department of Food Science and Technology Federal University of Santa Catarina-UFSCRod.Admar GonzagaFlorianópolis-SCBrazil

INTRODUCTION:Ensuring food safety is a challenge for developed and developing countries and depends on the combined efforts of government,regulators,academia,consumers,food producers,and ***:In this work,an overview of the main regulatory aspects related to chemical hazards in the Brazilian food and beverage industry is *** presence of contaminants,food additives,and residues of pesticides and veterinary drugs,including current regulations and their impacts on the safety and quality of locally produced foods,are ***:In Brazil,the assessment,management,and communication of human health risks in food and beverage are the joint responsibility of the Ministry of Health and the Ministry of Agriculture,Livestock and Food Supply,which enforce the international regulations established mainly by the Codex Alimentarius Commission,the European Commission,and the US Food and Drug ***:Constant updates of the national legislation following internationally recognized standards,the intensification of the existing monitoring plans and efficient actions of sanitary surveillance,major investments in scientific research,and a greater awareness among the food producers may contribute to the safety and quality of the food produced in Brazil.

关键词： Food safety Regulation Food and beverage Industry Health risks Chemical contamination.

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