1. The function of mating plugs in the spider Neriene emphana: mating strategy or sperm protection?Shuang Tian, He Jiang, Yongjia Zhan, Qingqing Wu, Matjaž Kuntner, Lihong Tu, 2023, original scientific article Abstract: Introduction: It is generally thought that mating plugs, where present, impede or reduce the possibilities of female subsequent mating. Behavioral studies on numerous spiders, where mating plugs are common, have generally supported this function. However, mating plugs in spiders could plausibly serve other functions as well. Namely, the structure of entelegyne spermathecae—the morphology of most spiders—could require a mechanism that would prevent sperm from leakage, desiccation, and backflow. Although the form and function of mating plugs in several spider species imply their potential adaptation for sperm protection, this function has never been empirically tested. Methods: Here, we test whether mating plugs in the sheet-web spider Neriene emphana serve as a sperm protective device by investigating its genital morphology, its copulation process, and the precise formation of its amorphous mating plugs. Results: This species constructs secretion plugs through male-female cooperation. Additionally, we found sperm plugs to be formed as a side product of sperm transfer, as well as an intermediate type of secretion plugs. These plug materials are transferred in different mating stages as documented by variations in the rhythm of male palpal application during copulation. We showed that complete copulations always resulted in formation of secretion plugs at spermathecal entrances via laborious deposition of male materials. Discussion: While our findings do not reject that secretion plugs in N. emphana prevent females from subsequent mating, we suggest that they must have evolved to provide sperm protection. Keywords: entelegyne spermatheca, mating behavior, mating strategy, sperm protection mechanism, mating plug, secretion plug, sperm plug Published in DiRROS: 15.07.2024; Views: 47; Downloads: 14
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2. A spider mating plug functions to protect spermHe Jiang, Yongjia Zhan, Qingqing Wu, Huitao Zhang, Matjaž Kuntner, Lihong Tu, 2024, original scientific article Abstract: Mating plugs in animals are ubiquitous and are commonly interpreted to be products of mating strategies. In spiders, however, mating plugs may also take on functions beyond female remating prevention. Due to the vagaries of female genital (spermathecal) anatomy, most spiders face the problem of having to secure additional, non-anatomical, protection for transferred sperm. Here, we test the hypothesis that mating plugs, rather than (or in addition to) being adaptations for mating strategies, may serve as sperm protection mechanism. Based on a comparative study on 411 epigyna sampled from 36 families, 187 genera, 330 species of entelegyne spiders, our results confirm the necessity of a sperm protection mechanism. We divided the entelegyne spermathecae into four types: SEG, SED, SCG and SCD. We also studied detailed morphology of epigynal tracts in the spider Diphya wulingensis having the SEG type spermathecae, using 3D-reconstruction based on semi thin histological series section. In this species, we hypothesize that two distinct types of mating plug, the sperm plug and the secretion plug, serve different functions. Morphological details support this: sperm plugs are formed on a modified spermathecal wall by the spilled sperm, and function as a temporary protection mechanism to prevent sperm from leaking and desiccating, while secretion plugs function in postcopulation both as a permanent protection mechanism, and to prevent additional mating. Furthermore, with the modified spermathecal wall of S2 stalk, the problem of shunt of sperm input and output, and the possibility of female multiple mating have been resolved. Variation in spermathecal morphology also suggests that the problem of sperm protection might be resolved in different ways in spiders. Considering mating plugs of varying shapes and origins in the vast morphospace of spiders, we conclude that mating plugs might serve different purposes that relate both to mating strategies, as well as to sperm protection. Keywords: spiders, mating strategies, mating plugs, sperm protection mechanism Published in DiRROS: 19.06.2024; Views: 124; Downloads: 61
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3. Mechanism of action, potency and efficacy : considerations for cell therapiesCarl G. Simon Jr., Erich H. Bozenhardt, Christina M. Celluzzi, David Dobnik, Melanie L. Grant, Uma Lakshmipathy, Thiana Nebel, 2024, original scientific article Abstract: One of the most challenging aspects of developing advanced cell therapy products (CTPs) is defining the mechanism of action (MOA), potency and efficacy of the product. This perspective examines these concepts and presents helpful ways to think about them through the lens of metrology. A logical framework for thinking about MOA, potency and efficacy is presented that is consistent with the existing regulatory guidelines, but also accommodates what has been learned from the 27 US FDA-approved CTPs. Available information regarding MOA, potency and efficacy for the 27 FDA-approved CTPs is reviewed to provide background and perspective. Potency process and efficacy process charts are introduced to clarify and illustrate the relationships between six key concepts: MOA, potency, potency test, efficacy, efficacy endpoint and efficacy endpoint test. Careful consideration of the meaning of these terms makes it easier to discuss the challenges of correlating potency test results with clinical outcomes and to understand how the relationships between the concepts can be misunderstood during development and clinical trials. Examples of how a product can be “potent but not efficacious” or “not potent but efficacious” are presented. Two example applications of the framework compare how MOA is assessed in cell cultures, animal models and human clinical trials and reveals the challenge of establishing MOA in humans. Lastly, important considerations for the development of potency tests for a CTP are discussed. These perspectives can help product developers set appropriate expectations for understanding a product’s MOA and potency, avoid unrealistic assumptions and improve communication among team members during the development of CTPs. Keywords: cell therapy product, efficacy endpoint test, mechanism of action, potency test, metrology Published in DiRROS: 27.05.2024; Views: 183; Downloads: 152
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4. The role of relative humidity on crystallization of calcium carbonate from calcium acetoacetate precursorAndreja Pondelak, Francesca Rosi, Celeste Maurich, Costanza Miliani, Srečo D. Škapin, Andrijana Sever Škapin, 2019, original scientific article Abstract: Calcium acetoacetate, Ca(OAcAc)2, was exposed 7, 30 and 365 days to different values of relative humidity (33%, 48%, 75% and 96%) at 40 °C in order to study its transformation to CaCO3. The resulting Ca(OAcAc)2 decomposition and the time dependence of the phase transformations were monitored and critically evaluated by Fourier transform infrared spectroscopy, field emission scanning electron microscopy and X-ray powder diffraction. The impact of relative humidity on CaCO3 polymorph formation was thoroughly assessed. In all of the conditions used and for all ageing periods, the formed crystal structure is found to be vaterite. At the lowest relative humidity (33%), the amorphous CaCO3 remains more or less almost untransformed even after one year of exposure. It is proposed that the reason for the stability of amorphous CaCO3 is due to the limited amount of physisorbed water on the surfaces of the particles, which is considered the driving force for its transformation. However, the carbonation process is faster in the case of the highest humidity (96%). The findings are not only important for better solutions in the field of cultural heritage, but also shed new light on the fundamental mechanism of CaCO3 crystallization. Keywords: calcium acetoacetate, relative humidity, carbonation, amorphous carbonate, vaterite, mechanism Published in DiRROS: 22.11.2023; Views: 513; Downloads: 214
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5. Catalytic lignin valorisation by depolymerisation, hydrogenation, demethylation and hydrodeoxygenation : mechanism, chemical reaction kinetics and transport phenomenaTina Ročnik, Blaž Likozar, Edita Jasiukaityte, Miha Grilc, 2022, review article Keywords: lignin, valorisation, depolymerisation, mechanism, kinetic modelling, transport phenomena Published in DiRROS: 01.07.2022; Views: 681; Downloads: 459
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8. Photocatalytic, electrocatalytic and photoelectrocatalytic degradation of pharmaceuticals in aqueous media : analytical methods, mechanisms, simulations, catalysts and reactorsBelisa Alcantara Marinho, Luka Suhadolnik, Blaž Likozar, Matej Huš, Živa Marinko, Miran Čeh, 2022, review article Keywords: advanced oxidation process, persistent organic compounds, pharmaceutical by- products, degradation mechanism, reactor design, analytical methods Published in DiRROS: 10.03.2022; Views: 779; Downloads: 584
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9. Catalytic hydrocracking reactions of tetralin biomass tar model compound to benzene, toluene and xylenes (BTX) over metal-modified ZSM-5 in ambient pressure reactorAndrii Kostyniuk, David Bajec, Blaž Likozar, 2022, original scientific article Keywords: catalytic hydrocracking reactions, ring opening mechanism, model biomass tar, benzene/toluene/xylenes (BTX), metal-doped HZSM-5 zeolite material, deposited coke deactivation Published in DiRROS: 10.03.2022; Views: 815; Downloads: 597
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10. Mechanisms of copper-based catalyst deactivation during CO [sub] 2 reduction to methanolAnže Prašnikar, Andraž Pavlišič, Francisco Ruiz-Zepeda, Janez Kovač, Blaž Likozar, 2019, original scientific article Keywords: catalyst deactivation, methanol synthesis, deactivation mechanism, modelling Published in DiRROS: 24.11.2020; Views: 1444; Downloads: 1040
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