检索结果-南通市图书馆

Journal of Modern Physics 2015年第4期6卷 483-489页

作者： eduardo Correa Regina Medeiros Maria da Penha Potiens Vitor Vivolo nathalia Costa Camila Murata Cristina Kikuti Instituto de Pesquisas energéticas e Nucleares (IPeN-CNeN) Universityof Sao Paulo (USP) Sao Paulo Brazil Federal University of Sao Paulo (UNIFeSP) Sao Paulo Brazil

This study presents the results of the preliminary tests performed using a kerma-area product (KAP) meter in order to verify its usefulness as a monitor chamber in a clinical X ray system, which will be used in ionization chambers’ quality control program. The tests performed were repeatability, surface measurement uniformity, linearity with tube current, measurement variation changing the distance and field size, KAP chamber radiation attenuation, and energy dependence. The KAP meter has presented a good repeatability (a maximum variation of 0.4%);its surface has a homogeneous response (a maximum variation of 1.0% among the different irradiated regions);the response is linear with the tube current and the variation of the PKA along the distance is less than 3.43%. On the other hand, the results obtained for chamber attenuation and energy dependence show that some corrections must be applied when the measurements are made. The results have shown a good performance of the KAP meter, confirming that it is possible to use this instrument as a monitor chamber. However, it is important to highlight that some correction factors for energy dependence and chamber radiation attenuation must be considered.

关键词： KAP Meter Quality Control Diagnostic Radiology Monitor Chamber

Only Attract Ants?The Versatility of Petiolar extrafloral Nectaries in Passiflora

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

American Journal of Plant Sciences 2013年第2期4卷 460-469页

作者： Poliana Cardoso-Gustavson nathalia L.Andreazza Alexandra C.H.F.Sawaya Marilia de Moraes Castro Pós-Graduacao em Biologia Vegetal Instituto de BiologiaUniversidade Estadual de CampinasCampinasBrazil Núcleo de Pesquisa em Anatomia Vegetal Instituto de BotanicaSao PauloBrazil Departamento de Biologia Vegetal Instituto de BiologiaUniversidade Estadual de CampinasCampinasBrazil

Passiflora species presents a coevolutive relationship with Heliconiini butterflies, their primary herbivores. The Heliconiini caterpillars are able to detoxify toxic compounds produced by Passiflora, thus morphological defense strategies stand out over chemical innovations. In this framework, we highlight the presence of mimetic structures and extrafloral nectaries (eFN) as morphological strategies. Heliconian butterflies oviposit only on leaves that do not possess previous eggs, so the presence of egg mimics could prevent the oviposition. eFN are glands that offer nectar to territorial and aggressive ants, establishing mutualistic relationships. Here, we present a structural and chemical analysis of petiolar eFN and nectar from Passiflora alata and P. edulis in order to have insights about the implications of these features in deterring heliconian caterpillars. P. alata have one to four stipitate-crateriform eFN while P. edulis possess a pair of convex glands. Butterflies lay their eggs isolatedly or in up to three on leaves of both species. Our morphological results suggest that eFN from P. alata may act as egg mimics. Ontogenetic data suggest that the variation in the number of glands observed in this species is a serial homology, wherein the selection pressure for this variation is possibly the oviposition pattern. P. alata retain alkaloids, flavonoids and terpenoids inside nectariferous cells;sugars and flavonoids are found in the nectar of both species, while alkaloids are also detected in P. edulis. There is a selective retention/release of secondary metabolites from the eFN tissues to nectar. Knowing that these compounds can be dissuasive to some herbivores and inoffensive to others, we plotted this relationship in a consumer growth versus secondary metabolite concentration diagram. Our results suggest a more active role in the modulation of the gland defense from plants besides the establishment of a mutualistic relationship with ants, an important respons

关键词： Passiflora alata Curtis Passiflora edulis Sims egg Mimics Anatomy Secondary Metabolites

Laser-Treated Surfaces for VADs:From Inert Titanium to Potential Biofunctional Materials

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Biomedical engineering Frontiers 2022年第1期3卷 399-406页

作者： eduardo Bock Wilhelm Pfleging Dayane Tada erenilda Macedo nathalia Premazzi Rosa Sá Juliana Solheid Heino Besser Aron Andrade Laboratory of Bioengineering and Biomaterials Federal Institute of Technology in Sao Paulo(IFSP)Sao PauloBrazil Center of engineering in Circulatory Assistance Institute Dante Pazzanese of Cardiology(IDPC)Sao PauloBrazil Institute for Applied Materials-Applied Materials Physics Karlsruhe Institute of Technology(KIT)KarlsruheGermany Federal University of Sao Paulo(UNIFeSP) Sao Jose dos CamposBrazil National Institute for Space Research(INPe) Sao Jose dos CamposBrazil

***-treated surfaces for ventricular assist *** *** work has scientific impact since it proposes a biofunctional surface created with laser processing in bioinert *** diseases are the world’s leading cause of *** especially debilitating heart disease is congestive heart *** the possible therapies,heart transplantation and mechanical circulatory assistance are the main treatments for its severe form at a more advanced *** development of biomaterials for ventricular assist devices is still being carried *** polished titanium is currently employed in several devices,its performance could be improved by enhancing the bioactivity of its *** to improve the titanium without using coatings that can be detached,this work presents the formation of laser-induced periodic surface structures with a topology suitable for cell adhesion and neointimal tissue *** surface was modified by femtosecond laser ablation and cell adhesion was evaluated in vitro by using fibroblast *** results indicate the formation of the desired topology,since the cells showed the appropriate adhesion compared to the control *** electron microscopy showed several positive characteristics in the cells shape and their surface *** in vitro results obtained with different topologies point that the proposed LIPSS would provide enhanced cell adhesion and *** laser processes studied can create new interactions in biomaterials already known and improve the performance of biomaterials for use in ventricular assist devices.

关键词： titanium biomaterials Titanium

Determination of Paraquat in Several Commercially Available Types of Rice

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Food and Nutrition Sciences 2018年第12期9卷 1368-1375页

作者： Thais Lopes Lima Maria Aparecida Nicoletti Camila Munhoz Gabriel Ramos De Abreu Julia Zaccarelli Magalhaes esther Lopes Ricci Ricci Paula A.Faria Waziry Júlia nathalia Alves da Costa Ana Carolina Nascimento Antonio AndréRinaldi Fukushima Universidade Sao Judas Tadeu-R.Taquari Sao Paulo/SPBrazil Departamento de Farmacia.Faculdade de Ciencias Farmaceuticas.Universidade de Sao Paulo Sao Paulo/SPBrazil Instituto de Ciencias da Saude Universidade Presbiteriana MackenzieRua da ConsolacaoSao Paulo/SPBrazil Departamento de Patologia Faculdade de Medicina Veterinaria e ZootecniaUniversidade de Sao PauloSao Paulo/SPBrazil New Southeastern University Fort LauderdaleFloridaUnited States of America Veterans Affairs Medical CenterMiamiFloridaUSA Faculdade Sao Bento-Largo de Sao Bento s/no-CentroSao Paulo-SPSao Paulo/SPBrazil

Introduction: Paraquat (1,1’-dimethyl-4,4’-bipyridine-dichloride) is a herbicide used to combat weeds and improve crop productivity. Its acute toxicity can cause fatal poisoning in humans and animals and several studies have shown a strong correlation between paraquat and Parkinson’s disease. Objective: To determine the concentration of paraquat in different types of rice in Brazil. Method: Paraquat quantification is based on a complexation reaction with sodium dithionite, which generates a blueish color compound, whose absorbance was read in a spectrophotometer at the 600 nm wavelength. Results: Five samples were found to be above the maximum allowed limit, while one sample had a concentration in the upper allowed limit. The method employed did not allow quantification of black rice. Conclusion: There is a need for identification of the type of pesticide used in each examined crop as well as their respective dates of remission in order to improve the safety of agricultural practices.

关键词： Paraquat Herbicide Rice