1. A spider mating plug functions to protect spermHe Jiang, Yongjia Zhan, Qingqing Wu, Huitao Zhang, Matjaž Kuntner, Lihong Tu, 2024, izvirni znanstveni članek Povzetek: 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.
Ključne besede: spiders, mating strategies, mating plugs, sperm protection mechanism
Objavljeno v DiRROS: 19.06.2024; Ogledov: 111; Prenosov: 56
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2. 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, izvirni znanstveni članek Povzetek: 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.
Ključne besede: cell therapy product, efficacy endpoint test, mechanism of action, potency test, metrology
Objavljeno v DiRROS: 27.05.2024; Ogledov: 182; Prenosov: 152
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3. 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, izvirni znanstveni članek Povzetek: 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.
Ključne besede: calcium acetoacetate, relative humidity, carbonation, amorphous carbonate, vaterite, mechanism
Objavljeno v DiRROS: 22.11.2023; Ogledov: 510; Prenosov: 212
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4. Catalytic lignin valorisation by depolymerisation, hydrogenation, demethylation and hydrodeoxygenation : mechanism, chemical reaction kinetics and transport phenomenaTina Ročnik, Blaž Likozar, Edita Jasiukaityte, Miha Grilc, 2022, pregledni znanstveni članek Ključne besede: lignin, valorisation, depolymerisation, mechanism, kinetic modelling, transport phenomena
Objavljeno v DiRROS: 01.07.2022; Ogledov: 677; Prenosov: 459
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7. 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, pregledni znanstveni članek Ključne besede: advanced oxidation process, persistent organic compounds, pharmaceutical by- products, degradation mechanism, reactor design, analytical methods
Objavljeno v DiRROS: 10.03.2022; Ogledov: 777; Prenosov: 584
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8. 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, izvirni znanstveni članek Ključne besede: catalytic hydrocracking reactions, ring opening mechanism, model biomass tar, benzene/toluene/xylenes (BTX), metal-doped HZSM-5 zeolite material, deposited coke deactivation
Objavljeno v DiRROS: 10.03.2022; Ogledov: 813; Prenosov: 594
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9. Mechanisms of copper-based catalyst deactivation during CO [sub] 2 reduction to methanolAnže Prašnikar, Andraž Pavlišič, Francisco Ruiz-Zepeda, Janez Kovač, Blaž Likozar, 2019, izvirni znanstveni članek Ključne besede: catalyst deactivation, methanol synthesis, deactivation mechanism, modelling
Objavljeno v DiRROS: 24.11.2020; Ogledov: 1423; Prenosov: 1036
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10. A review of methane activation reactions by halogenation : catalysis, mechanism, kinetics, modeling, and reactorsDavid Bajec, Matic Grom, Damjan Lašič Jurković, Andrii Kostyniuk, Matej Huš, Miha Grilc, Blaž Likozar, Andrej Pohar, 2020, pregledni znanstveni članek Ključne besede: methane, halogenation, catalysis, density functional theory, kinetics, mechanism
Objavljeno v DiRROS: 16.04.2020; Ogledov: 2240; Prenosov: 1410
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