Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Estudos em animais experimentais evidenciaram associações significativas entre esquistossomose mansoni e hipercolesterolemia. Estudos in vitro e in vivo já demonstraram que o colesterol é essencial para Schistosoma mansoni, embora este não tenha capacidade de sintetizá-lo. A captação é realizada a partir do ambiente (cultivo ou hospedeiro) através do tegumento. O colesterol está envolvido nos mecanismos de evasão do helminto contra a resposta imunológica, além de poder participar na modulação da sinalização celular e reprodução, estimulando os órgãos reprodutores dos helmintos adultos como observado na fase aguda da infecção experimental. Este trabalho tem como objetivo avaliar se o mesmo fenômeno ocorre na fase crônica. Os helmintos foram recuperados de dez camundongos submetidos à dieta hiperlipídica ou padrão (controle) foram corados pelo carmin cloridrico e montados, individualmente, em lâmina histológica com bálsamo do Canadá. A preparação foi analisada por microscopia de campo claro nos seguintes caracteres: tegumento e o sistema reprodutor nos vermes machos (lobos testiculares, vesícula seminal, lobos testiculares supranumerários e canal ginecóforo) e, nas fêmeas (ovário, oótipo, útero, ovo, glândulas vitelínicas e espermateca). Posteriormente, algumas lâminas foram separadas para visualização pela microscopia confocal dos órgãos do sistema reprodutores acima descritos. Apesar de ter sido observado uma maior quantidade de espermatozoides, uma maior quantidade de oócitos sendo liberados no grupo da dieta, não houve diferença estatística significativa (p>0,05) entre os grupos analisados. Houve um aumento na oogênese como observado na fase aguda. Dessa forma, o colesterol pode estar relacionado com a estimulação na atividade dos órgãos reprodutores dos helmintos adultos na fase crônica da infecção. / Studies in experimental animals showed significant associations between with schistosomiasis and hypercholesterolemia. In vitro and in vivo studies have demonstrated that cholesterol is essential for Schistosoma mansoni, although this is not able to synthesize it. The capture is carried out from the environment (cultivation or host) through the tegument. The capture is carried out from the middle (cultivation or host) through the tegument. Cholesterol is involved in the helminth evasion mechanisms against the immune response, and can participate in the modulation of cell signaling and reproduction of worms by stimulating the reproductive organs of adult worms as observed in the acute phase of experimental infection. This study aims to evaluate whether the same phenomenon occurs in the chronic phase. Helminthes recovered from ten mice subjected to high fat diet or standard (control) were stained with hydrochloric carmine and mounted individually on histological slide with Canada balsam. The preparation was analyzed by bright field microscopy the following characteristics: oral sucker and ventral sucker, tubercles on tegument and the reproductive system in male worms (lobes testicular, seminal vesicles, supernumerary testicular lobes and gynaecophoric canal), and in females (ovary, ootype, uterus, egg, vitelline glands and spermatheca). Subsequently, some slides were separated for confocal microscopy for visualization of the organs of the reproductive system described above. Despite having been observed a higher amount of sperm, a larger number of oocytes are released in the diet group, there was no statistically significant difference (p> 0.05) between the groups. There was an increase in oogenesis as observed in the acute phase. Thus, cholesterol may be related to the stimulation of the activity of the reproductive organs of adult helminths in the chronic phase of infection.

O objetivo deste estudo in vitro foi avaliar o potencial erosivo de suco de fruta amazônica ácida sobre a superfície dentinaria associado ao efeito abrasivo de diversos cremes dentais contendo agentes dessensibilizantes. O trabalho foi dividido em 3 fases distintas: Na fase 1, o valor do pH inicial de diversas frutas amazônicas foi medido utilizando 50 ml de cada suco, obtido de polpa industrializada. Foi utilizado um eletrodo de pH calibrado e a água destilada foi utilizada como controle. Na fase 2, 120 espécimes de dentina bovina foram submetidos a ciclos alternados de desafio abrasivo e erosivo, com a fruta escolhida na fase 1. Os espécimes foram divididos aleatoriamente em Grupo A (Desafio Abrasivo) e Grupo B (Desafio Erosivo e Abrasivo). Cada um destes grupos foram subdivididos em 5 subgrupos: 1: Água Destilada (Controle Negativo), 2: Colgate Tripla Ação (Controle Positivo), e os demais de acordo com o creme dental utilizado 3: Sensodyne Rápido Alívio, 4: Colgate Pró-Alivio e 5: Sensodyne Repair&Protect, (n=9). Na fase 3 foi realizado microscopia eletrônica de varredura para avaliar qualitativamente os espécimes (n=3). - O suco da fruta taperebá (Spondias mombin) apresentou os menores valores de pH, diante disso, foi escolhido como agente erosivo; Os testes de Kruskall Wallis e Teste de Dunn, mostraram que para os grupos nos quais somente a abrasão foi realizada, todos os cremes dentais mostraram comportamentos semelhantes em relação a perfilometria, não havendo diferença estatisticamente significante entre os grupos. Porém, para os grupos nos quais o processo erosivo foi adicionado, observou-se a potencialização do processo abrasivo, sendo que os cremes dentais Sensodyne Rápido Alivio e Colgate Sensitive Pro-Alivio foram os que mostraram menores alterações superficiais no padrão de perfilometria, comparados com o grupo controle negativo. Já os cremes dentais, Colgate Tripla Ação (controle positivo) e Sensodyne Repair&Protect apresentaram-se semelhantes entre si e com uma perda de estrutura dentinaria. mais significante. Conclui-se que o efeito erosivo da fruta amazônica taperebá é fator de grande importância na potencialização do efeito abrasivo, mesmo quando do uso de cremes dentais com agentes dessensibilizantes.. Na análise qualitativa da superfície dentinária em MEV, com exceção do Colgate tripla ação, os demais grupos não apresentaram oclusão tubular após o desafio ácido / The aim of this in vitro study was to evaluate the erosive potential of amazonian fruit juice with or without the abrasive challenge with various toothpastes containing desensitizing agents. The work was divided into three phases: in phase 1, the pH of various Amazonian fruits was evaluated. In step 2 it was performed surface perfilometry of the specimens, and in phase 3 it was evaluated qualitatively the dentin surface. In step 1, the initial pH value of several amazonian fruits was measured using 50 mL of each juice, from industrialized pulp. It was used a calibrated pH electrode, and distilled water was used as control. In step 2, 120 bovine dentin specimens were subjected to alternate cycles of abrasive and erosive challenge, with the fruit chosen in step 1. The specimens were randomly divided into Group A (without erosion) and Group B (with erosion). Each of these groups were divided into 5 groups: 1: Distilled Water, 2: Colgate Tripla Ação, 3: Sensodyne Rápido Alívio, 4: Pro-Alivio, 5: Sensodyne Repair & Protect, (n = 9). In Phase 3 it was conducted scanning electron microscopy to evaluate qualitatively the specimens (n=3). As a result it can be stated that: 1. The juice of the taperebá fruit had the lowest pH values, so it was chosen as the erosive agent; 2. For the groups in which only the abrasion was performed, all toothpastes showed similar behaviors, no statistically significant difference was observed between groups, but for the groups in which the erosion process was added, there was a potentiation of the abrasive process, and the toothpastes showed different profiles. The toothpaste Sensodyne Rapido Alívio Pró-Alívio was the ones that showed lower mineral loss, compared with the negative control group. Colgate Tripla Ação and Sensodyne Repair&Protect were similar among themselves and with a more significant mineral loss. It can be conclude that erosive effect of diet is a factor of great importance in the potentiation of abrasive effect. Clinical studies are essential to determine the dentin hypersensitivity levels after use of toothpaste used.

Dans le cadre de ce travail de doctorat, nous avons mis au point un nouveau microscope à balayage à transistor à électron unique (SET) qui fonctionne à très basse température (T = 50 mK) et à champs magnétiques intenses (18 T). Un SET se compose d'un petit îlot métallique relié aux électrodes de source et de drain par deux jonctions tunnel. En régime de blocage de Coulomb à basse température (T < 5 K), un champ électrique externe règle le courant circulant dans le SET. De plus, de petites variations du champ électrique entraînent de grandes variations du courant SET, ce qui fait de l'appareil un détecteur de charge très sensible, capable de détecter des charges inférieures à 0,01e. Ainsi, lorsque le SET scanne au-dessus d'une surface, il cartographie les propriétés électrostatiques de l'échantillon. Cependant, la mise en œuvre d'un microscope à balayage SET est extrêmement difficile car il combine la microscopie à sonde à balayage, les basses températures et les dispositifs nanoscopiques très sensibles. Pour cette raison, seuls quelques groupes ont réussi sa réalisation. Nos choix technologiques pour construire le microscope améliorent certains aspects par rapport aux instruments déjà existants.La percée est que nous fabriquons la sonde SET en utilisant des techniques lithographiques standard sur des plaquettes commerciales de silicium. C'est pourquoi il est possible de fabriquer des sondes SET par lots. De plus, grâce à une combinaison de techniques de découpage et de gravure, le SET est conçu très près du bord du substrat de Si (< 1 micromètre ). De cette façon, le SET peut être approché à quelques nanomètres de la surface de l'échantillon au moyen d'un contrôle de distance de force atomique. De plus, une électrode de grille fabriquée sur la sonde à proximité de l'îlot peut être utilisée pour régler le point de fonctionnement du SET. Une nouveauté de notre instrument est qu'avec cet électrode de grille et une boucle de rétroaction, nous avons cartographié directement le champ électrique local. Nous démontrons cette nouvelle méthode de balayage par rétroaction en imaginant un réseau interdigité d'électrodes à l'échelle nanométrique. De plus, le SET est un outil idéal pour l'étude de la localisation d'états électroniques. À l'avenir, notre microscope sera utilisé pour l'étude des systèmes d'électrons bidimensionnels en régime de l'effet Hall quantique, des isolants topologiques et de la transition métal-isolant. / In this doctoral work, we have developed a new scanning single electron transistor (SET) microscope that works at very low temperatures (T = 50 mK) and high magnetic fields (B = 18 T). A SET consists of a small metallic island connected to source and drain electrodes through two tunnel junctions. In the Coulomb blockade regime at low temperature regime (T 5 K), an external electric field tunes the current circulating through the SET. In addition,small electric field variations lead to large SET current changes that makes the device a highly sensitive charge detector, able to detect charges smaller than 0.01 e. Thus, when the SET scans above a surface, it maps the electrostatic properties of the sample. However, the implementation of a scanning SET microscope is extremely challenging since it combines scanning probe microscopy, low temperatures and sensitive nanoscopic devices. For thisreason, only a few groups have succeeded its realization. Our technological choices to build the microscope improve certain aspects with respect to the already existing instruments. The breakthrough is that we fabricate the SET probe using standard lithographic techniques on commercial silicon wafers.For that reason, batch fabrication of SET probes is possible. Furthermore, by a combination of dicing and etching techniques, the SET is engineered extremely close to the edge of the Si chip (< 1 micrometer). In this way, the SET can be approached to a few nanometer from the sample surface by means of a atomic force distance control. Additionally, an on-probe gate electrode fabricated close to the island can be used to tune the operating point of the SET. Anovelty of our instrument is that with this on-probe gate and a feedback loop we have been able to map directly the local electric field. We demonstrate this new feedback scanning method by imaging an interdigitated array of nanometer scale electrodes. Moreover, the SET is an ideal tool for the study of the localization of electronic states. In the future, our scanning SET will be used for the study of two-dimensional electron systems in the quantum Hall regime, topological insulators and the metal insulator transition.

Physical and functional properties of advanced nano-composite materials and biological structures are determined by self-organized atoms and molecules into nanostructures and in turn by microscopic organization of the nanostructures into assemblies of higher structural complexity. Therefore, microscopes are indispensable tools for structural investigations at various levels of organization. In this work, novel nonlinear optical microscopy methods were developed to non-invasively study structural organization at the nanoscopic and microscopic levels. Atomic organization of semiconductor nanowires, molecular organization of amylose biocrystallites in starch granules, and microscopic organization of several photosynthetic organisms was elucidated. The structure of ZnSe nanowires, key components in many modern nanodevices, was investigated using polarization harmonic generation microscopy. Based on nonlinear optical properties of the different crystal lattices, zinc blende and wurtzite nanowires were differentiated, and the three-dimensional orientation of the zinc blende nanowires could be found. The structure of starch granules, a model biocrystal, important in food as well as health sciences, was also investigated using polarization harmonic microscopy. The study was combined with ab initio calculations using the crystal structures of amylose A and B, revealing that second harmonic signals originate from the hydroxide and hydrogen bonds in the starch granules. Visualization of several photosynthetic organisms including the green algae, Chlamydomonas reinhardtii, two species of cyanobacteria, Leptolyngbya sp. and Anabaena sp., aggregates of light-harvesting pigment-protein complexes as well as chloroplasts from green plants were also explored, revealing that future nonlinear microscopy applications could include structural studies of cell walls, the Chlamydomonas eyespot, and photosynthetic membranes. In this study, several nonlinear optical microscopy modalities were developed for quantitative structural investigations of nano and micro-sized architectures. Non-invasive extraction of crystallographic information in microscopic samples will have a number of potential benefits, for example, in clinical applications, allowing observations of disease states inside tissues without the need for biopsy. Industrial nanotechnology will benefit from fast determination of nanostructures with nonlinear microscopy that will improve quality of nanodevices.

Physical and functional properties of advanced nano-composite materials and biological structures are determined by self-organized atoms and molecules into nanostructures and in turn by microscopic organization of the nanostructures into assemblies of higher structural complexity. Therefore, microscopes are indispensable tools for structural investigations at various levels of organization. In this work, novel nonlinear optical microscopy methods were developed to non-invasively study structural organization at the nanoscopic and microscopic levels. Atomic organization of semiconductor nanowires, molecular organization of amylose biocrystallites in starch granules, and microscopic organization of several photosynthetic organisms was elucidated. The structure of ZnSe nanowires, key components in many modern nanodevices, was investigated using polarization harmonic generation microscopy. Based on nonlinear optical properties of the different crystal lattices, zinc blende and wurtzite nanowires were differentiated, and the three-dimensional orientation of the zinc blende nanowires could be found. The structure of starch granules, a model biocrystal, important in food as well as health sciences, was also investigated using polarization harmonic microscopy. The study was combined with ab initio calculations using the crystal structures of amylose A and B, revealing that second harmonic signals originate from the hydroxide and hydrogen bonds in the starch granules. Visualization of several photosynthetic organisms including the green algae, Chlamydomonas reinhardtii, two species of cyanobacteria, Leptolyngbya sp. and Anabaena sp., aggregates of light-harvesting pigment-protein complexes as well as chloroplasts from green plants were also explored, revealing that future nonlinear microscopy applications could include structural studies of cell walls, the Chlamydomonas eyespot, and photosynthetic membranes. In this study, several nonlinear optical microscopy modalities were developed for quantitative structural investigations of nano and micro-sized architectures. Non-invasive extraction of crystallographic information in microscopic samples will have a number of potential benefits, for example, in clinical applications, allowing observations of disease states inside tissues without the need for biopsy. Industrial nanotechnology will benefit from fast determination of nanostructures with nonlinear microscopy that will improve quality of nanodevices.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Estudos em animais experimentais evidenciaram associações significativas entre esquistossomose mansoni e hipercolesterolemia. Estudos in vitro e in vivo já demonstraram que o colesterol é essencial para Schistosoma mansoni, embora este não tenha capacidade de sintetizá-lo. A captação é realizada a partir do ambiente (cultivo ou hospedeiro) através do tegumento. O colesterol está envolvido nos mecanismos de evasão do helminto contra a resposta imunológica, além de poder participar na modulação da sinalização celular e reprodução, estimulando os órgãos reprodutores dos helmintos adultos como observado na fase aguda da infecção experimental. Este trabalho tem como objetivo avaliar se o mesmo fenômeno ocorre na fase crônica. Os helmintos foram recuperados de dez camundongos submetidos à dieta hiperlipídica ou padrão (controle) foram corados pelo carmin cloridrico e montados, individualmente, em lâmina histológica com bálsamo do Canadá. A preparação foi analisada por microscopia de campo claro nos seguintes caracteres: tegumento e o sistema reprodutor nos vermes machos (lobos testiculares, vesícula seminal, lobos testiculares supranumerários e canal ginecóforo) e, nas fêmeas (ovário, oótipo, útero, ovo, glândulas vitelínicas e espermateca). Posteriormente, algumas lâminas foram separadas para visualização pela microscopia confocal dos órgãos do sistema reprodutores acima descritos. Apesar de ter sido observado uma maior quantidade de espermatozoides, uma maior quantidade de oócitos sendo liberados no grupo da dieta, não houve diferença estatística significativa (p>0,05) entre os grupos analisados. Houve um aumento na oogênese como observado na fase aguda. Dessa forma, o colesterol pode estar relacionado com a estimulação na atividade dos órgãos reprodutores dos helmintos adultos na fase crônica da infecção. / Studies in experimental animals showed significant associations between with schistosomiasis and hypercholesterolemia. In vitro and in vivo studies have demonstrated that cholesterol is essential for Schistosoma mansoni, although this is not able to synthesize it. The capture is carried out from the environment (cultivation or host) through the tegument. The capture is carried out from the middle (cultivation or host) through the tegument. Cholesterol is involved in the helminth evasion mechanisms against the immune response, and can participate in the modulation of cell signaling and reproduction of worms by stimulating the reproductive organs of adult worms as observed in the acute phase of experimental infection. This study aims to evaluate whether the same phenomenon occurs in the chronic phase. Helminthes recovered from ten mice subjected to high fat diet or standard (control) were stained with hydrochloric carmine and mounted individually on histological slide with Canada balsam. The preparation was analyzed by bright field microscopy the following characteristics: oral sucker and ventral sucker, tubercles on tegument and the reproductive system in male worms (lobes testicular, seminal vesicles, supernumerary testicular lobes and gynaecophoric canal), and in females (ovary, ootype, uterus, egg, vitelline glands and spermatheca). Subsequently, some slides were separated for confocal microscopy for visualization of the organs of the reproductive system described above. Despite having been observed a higher amount of sperm, a larger number of oocytes are released in the diet group, there was no statistically significant difference (p> 0.05) between the groups. There was an increase in oogenesis as observed in the acute phase. Thus, cholesterol may be related to the stimulation of the activity of the reproductive organs of adult helminths in the chronic phase of infection.

Étude des mécanismes de la plasticité dans les verres métalliques massifs. Ce travail a porté sur une approche des mécanismes de la plasticité à la transition vitreuse dans les verres métalliques massifs base zirconium. Une étude bibliographique des verres métalliques, ses caractéristiques essentielles a été tout d'abord introduite, particulièrement orientée vers leurs propriétés de stabilité structurale, ainsi que vers leurs propriétés mécaniques à haute température. Le modèle de volume libre (selon l'approche de Spaepen) a été utilisé dans une modélisation par éléments finis de la plasticité du verre. Le verre métallique de composition Zr_{52,5}Cu_{22}Al_{10}Ni_{13}Ti_{2,5}, étudié dans cette thèse, est élaboré par différentes méthodes d'hypertrempe sous forme de barreaux et de rubans. Les caractérisations physico-chimiques ont été menées par DSC, DRX et MEB. Les résultats de DSC ont montré que les verres élaborés possèdent un large intervalle de transition vitreuse et une bonne stabilité thermique. L'étude couplant DSC et DRX à haute température a permis d'établir la nature des phases et leur ordre d'apparition en cours de cristallisation. La transition vitreuse et la cristallisation ont été étudiées en détail par DSC modulée (MDSC) par la suite. La cinétique de cristallisation du verre a été généralement analysée par DSC isotherme.La caractérisation de la relaxation du verre métallique à partir de traitements thermiques successifs, par DSC et DRX à température proche de la température de transition vitreuse T_g pendant des temps différents, est rapportée dans le quatrième chapitre. Ce phénomène de relaxation peut être observé directement par les études structurales en utilisant la DSC et la diffraction des rayons X. Ensuite, l'évolution de la relaxation du verre est étudiée par mesure de dureté et de densité. La variation de la dureté H_v par rapport à la profondeur de pénétrateur h, après les traitements thermiques, a été menée par micro-dureté. La mesure de volumique du verre Zr_{52,5}Cu_{22}Al_{10}Ni_{13}Ti_{2,5} a été menée après les différents temps de relaxation thermique, nous donnent une densité d'environ de 6,769g/cm^3. Les traitements thermiques isothermes sur ce verre ont montré une augmentation de sa densité au cours du temps. Afin d'observer l'apparition puis l'évolution des mécanismes de déformation dans le verre métallique à l'échelle locale, une nouvelle technique - lithographie électronique - avec un dispositif d'essai mécanique in situ, permettant de déposer des microgrilles à la surface d'une éprouvette et de réaliser un essai de compression dans un MEB, est présentée dans le cinquième chapitre. Puis, les résultats sont analysés par corrélation d'images. La démarche expérimentale des essais MEB in situ est détaillée dans ce chapitre.Des essais à vitesse de déformation constante sont présentées dans le chapitre suivant. Ils ont été conduits dans l'intervalle de transition vitreuse (entre 673K et 713K). Enfin, les études de champs de déformation par corrélation d'image ont montré une limite de détection de la localisation supérieure à 2 micromètre sur les cartes de déformation. S'il y a des bandes de cisaillement, soit leurs déformation en inférieure à celles due à l'oxydation, soit elles sont plus fines que 2 micromètre (échelle de mesure). Le dernier chapitre présente une modélisation pour décrire le comportement élastique et plastique des verres métalliques. Dans le cadre de cette thèse, une approche de la modélisation des essais mécanique en se basant sur le modèle du volume libre a été conduite à l'aide du logiciel ZéBulon. Des travaux préliminaires pour étudier la localisation dans le cadre du volume libre ont été conduits et vont nécessiter une étude plus poussée.Mots clef : verre métallique, transition vitreuse, relaxation structurale, volume libre, caractérisation, micro-dureté, lithographie, compression, MEB in situ, modélisation / Study of the mechanisms of the plasticity in the massive metallic glasses. This work concerned an approach of the mechanisms of the plasticity in the glassy transition in the massive metallic glasses base zirconium. A bibliographical study of the metallic glasses, its essential characteristics was introduced first of all, particularly directed to their properties of structural stability, as well as to their high-temperature mechanical properties. The model of free volume (according to the approach of Spaepen) was used in a modelling by elements finished by the plasticity of the glass. The metallic glass of composition Zr _ (52,5) Cu _ (22) Al _ {10} Nor _ (13) Ti _ {2,5}, studied in this thesis(theory), is developed by various methods of hypertempering in the form of bars and of ribbons.

No description available.

This master’s thesis deals with the design of methodology for measurement of refractive index and thickness of living cells by coherence-controlled holographic microscope. The theoretical part summarises the holographic microscopy and its development at IPE FME BUT in Brno. The thesis focuses on the multimodal holographic microscope, its description, the principle, the procedure of work and data processing. Confocal microscopy is also described, which serves to compare the acquired values with the proposed methodology. The last part of the theoretical part deals with the testing of statistical hypotheses, which is needed for the processing of measured data. Experiments were designed for the verification of methodology for determination of the refractive index and cell thickness. The experimental part of the thesis deals with the sample preparation and measurement. The procedure and results of the proposed experiments and their evaluation follows.

Background: Syllids are a species rich annelid family possessing remarkable regenerative ability, which is not only the response after traumatic injury, but also a key step during the life cycle of several syllid taxa. In these animals the posterior part of the body becomes an epitoke and is later detached as a distinct unit named stolon. Such a sexual reproductive mode is named schizogamy or stolonization. The prostomium and the proventricle, a modified foregut structure, have been proposed to have a control function during this process, though the concrete mechanisms behind it have never been elucidated. Results: By using different experimental set-ups, histology and immunohistochemistry combined with subsequent cLSM analyzes, we investigate and document the regeneration and stolonization in specimens of Typosyllis antoni that were amputated at different levels throughout the antero-posterior body axis. The removal of the anterior end including the proventricle implies an incomplete anterior regeneration as well as severe deviations from the usual reproductive pattern, i.e. accelerated stolonization, masculinization and the occurrence of aberrant stolons. The detailed anatomy of aberrant stolons is described. A histological study of the proventricle revealed no signs of glandular or secretory structures. The ventricle and the caeca are composed of glandular tissue but they are not involved in the reproductive and regenerative processes. Conclusions: As in other investigated syllids, the proventricle region has a significant role during stolonization and reproduction processes in Typosyllis antoni. When the proventricle region is absent, anterior and posterior regeneration are considerably deviated from the general patterns. However, proventricle ultrastructure does not show any glandular component, thereby questioning a direct involvement of this organ itself in the control of reproduction and regeneration. Our findings offer a comprehensive starting point for further studies of regeneration and reproductive control in syllids as well as annelids in general.