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971.
Jodi D. Weiss Shelby L. McVey Sarah E. Stinebaugh Caroline F. Sullivan R. Kelly Dawe Natalie J. Nannas 《International journal of molecular sciences》2022,23(8)
The success of an organism is contingent upon its ability to faithfully pass on its genetic material. In the meiosis of many species, the process of chromosome segregation requires that bipolar spindles be formed without the aid of dedicated microtubule organizing centers, such as centrosomes. Here, we describe detailed analyses of acentrosomal spindle assembly and disassembly in time-lapse images, from live meiotic cells of Zea mays. Microtubules organized on the nuclear envelope with a perinuclear ring structure until nuclear envelope breakdown, at which point microtubules began bundling into a bipolar form. However, the process and timing of spindle assembly was highly variable, with frequent assembly errors in both meiosis I and II. Approximately 61% of cells formed incorrect spindle morphologies, with the most prevalent being tripolar spindles. The erroneous spindles were actively rearranged to bipolar through a coalescence of poles before proceeding to anaphase. Spindle disassembly occurred as a two-state process with a slow depolymerization, followed by a quick collapse. The results demonstrate that maize meiosis I and II spindle assembly is remarkably fluid in the early assembly stages, but otherwise proceeds through a predictable series of events. 相似文献
972.
973.
Ezgi Ozen Rada G. Mihaylova Natalie J. Lord Julie A. Lovegrove Kim G. Jackson 《International journal of molecular sciences》2022,23(17)
Body mass index (BMI) has been suggested to play an important role in the relationship between the APOLIPOPROTEIN (APO)E genotype and cardiovascular disease (CVD) risk. Using data from the BODYCON cross-sectional study (n = 360 adults) we assessed the association between body composition and CVD risk markers according to APOE genotype, with examination of the role of BMI. In this study cohort, the APOE2/E3 group had lower fasting blood lipids than APOE4 carriers and APOE3/E3 group (p ≤ 0.01). After stratifying the group according to BMI, APOE4 carriers in the normal BMI subgroup had a higher lean mass compared with the APOE3/E3 group (p = 0.02) whereas in the overweight/obese subgroup, the android to gynoid percentage fat ratio was lower in APOE4 carriers than APOE3/E3 group (p = 0.04). Fasting lipid concentrations were only different between the APOE2/E3 and other genotype groups within the normal weight BMI subgroup (p ≤ 0.04). This finding was associated with a lower dietary fibre and a higher trans-fat intake compared with APOE4 carriers, and a lower carbohydrate intake relative to the APOE3/E3 group. Our results confirm previous reports that BMI modulates the effect of APOE on CVD risk markers and suggest novel interactions on body composition, with diet a potential modulator of this relationship. 相似文献
974.
975.
976.
Noah Strobel Nikolaos Droseros Wolfgang Köntges Mervin Seiberlich Manuel Pietsch Stefan Schlisske Felix Lindheimer Rasmus R. Schröder Uli Lemmer Martin Pfannmöller Natalie Banerji Gerardo Hernandez-Sosa 《Advanced materials (Deerfield Beach, Fla.)》2020,32(12):1908258
Future lightweight, flexible, and wearable electronics will employ visible-light-communication schemes to interact within indoor environments. Organic photodiodes are particularly well suited for such technologies as they enable chemically tailored optoelectronic performance and fabrication by printing techniques on thin and flexible substrates. However, previous methods have failed to address versatile functionality regarding wavelength selectivity without increasing fabrication complexity. This work introduces a general solution for printing wavelength-selective bulk-heterojunction photodetectors through engineering of the ink formulation. Nonfullerene acceptors are incorporated in a transparent polymer donor matrix to narrow and tune the response in the visible range without optical filters or light-management techniques. This approach effectively decouples the optical response from the viscoelastic ink properties, simplifying process development. A thorough morphological and spectroscopic investigation finds excellent charge-carrier dynamics enabling state-of-the-art responsivities >102 mA W−1 and cutoff frequencies >1.5 MHz. Finally, the color selectivity and high performance are demonstrated in a filterless visible-light-communication system capable of demultiplexing intermixed optical signals. 相似文献
977.
Dr. Syed Masood Husain Dr. Andreas Präg Dr. Anton Linnenbrink Prof. Dr. Andreas Bechthold Prof. Dr. Michael Müller 《Chembiochem : a European journal of chemical biology》2020,21(6):780-784
Partially reduced aromatic polyketides are bioactive secondary metabolites or intermediates in the biosynthesis of deoxygenated aromatics. For the antibiotic GTRI-02 (mensalone) in different Streptomyces spp., biosynthesis involving the reduction of a fully aromatized acetyltrihydroxynaphthalene by a naphthol reductase has been proposed and shown in vitro with a fungal enzyme. However, more recently, GTRI-02 has been identified as a product of the ActIII biosynthetic gene cluster from Streptomyces coelicolor A3(2), for which the reduction of a linear polyketide precursor by ActIII ketoreductase, prior to cyclization and aromatization, has been suggested. We have examined three different ketoreductases from bacterial producer strains of GTRI-02 for their ability to reduce mono-, bi-, and tricyclic aromatic substrates. The enzymes reduced 1- and 2-tetralone but not other aromatic substrates. This strongly suggests a reduction of a cyclized but not yet aromatic polyketide intermediate in the biosynthesis of GTRI-02. Implications of the results for the biosynthesis of other secondary polyketidic metabolites are discussed. 相似文献
978.
Marília Caroline C. de Sá Teresa Córdova Príamo A. Melo Ramón Díaz de León José Carlos Pinto 《加拿大化工杂志》2023,101(9):5256-5269
trans-β-Farnesene is a bio-derived terpene monomer that can polymerize, generating polymers with properties that can be similar to the properties of conventional petroleum-derived polymers. For this reason, in the present study, several coordination polymerizations of trans-β-farnesene are carried out using the Ziegler–Natta catalyst system composed by neodymium versatate (), diisobutylaluminum hidride (DIBAH), and dimethyldichlorosilane (DMDCS) in order to evaluate the influence of key operation variables on the control of average molar masses and monomer conversion. A phenomenological model is proposed to describe the coordination polymerization of trans-β-farnesene, and the kinetic parameters required to simulate the reactions are estimated. The initial concentration of DIBAH used as a chain transfer agent (CTA) is calculated by a data reconciliation procedure since this very active compound can participate in undesired side reactions. It is shown that the initial monomer, DIBAH, and concentrations exert strong influences on the monomer conversion and average molar masses of (poly)farnese while the temperature effect is not so pronounced. The proposed kinetic mechanism was able to predict well the experimental data collected during the reactions, with the successful reconciliation of CTA concentrations and estimation of model parameters. 相似文献
979.
Univ.-Prof. Dr.-Ing. habil. Natalie Stranghöner Lukas Makevičius Anas Korbaj Carsten Kunde Dipl.-Ing. 《Stahlbau》2023,92(1):27-38
The application of duroplastic gap filling material DIAMANT MM1018 in preloaded bolted connections In steel construction, bolted connections are preloaded either for load-bearing capacity reasons or for serviceability reasons. Single and multi-section connections of wind turbines, offshore plants, bridges etc. are typical application examples. Gap formation, caused by imperfections due to fabrication and assembly, poses a risk e. g. for the controlled application of the required preload level as well as for the prevention of cavity corrosion. This can significantly impair the load-bearing capacity and the durability of the connection and even lead to a premature failure. Therefore, the formation of gaps must be kept to a minimum, whereby DIN EN 1090-2 provides possible measures such as the use of packing plates for this purpose. Two-component reaction resin systems based on epoxy resins, which are filled with special metallic materials to improve the mechanical properties, are a possible alternative for gap filling. Within the framework of the ZIM cooperation project “Bri-San-T – DuroFüllSta”, systematic investigations were carried out into the use of the gap-filling material MM1018 of the company Diamant Polymer GmbH for use in preloaded bolted connections. In this contribution, experimentally determined slip factors as well as the expected preload losses over the service life are presented and discussed. 相似文献
980.
Ruben Jimenez-Redal Javier Soriano Natalie Holowko Jabier Almandoz Francisco Arregui 《国际水资源开发杂志》2018,34(6):1022-1035
ABSTRACTTo assess the sustainability of rural gravity-fed water schemes on Idjwi Island, the association between four hypothesized drivers of sustainability – perceived sense of ownership, willingness to pay for maintenance, trust in the water committee, and household involvement in the project – and service reliability, the main outcome variable, was analyzed. Primary data were gathered through in-person surveys of 1253 user households. The results provide two significant insights. First, during the 5–10 years after implementation, in the presence of an external intervention, a lower perceived sense of ownership for the water system was associated with higher service reliability. This stands in contrast with much of the existing literature, which outlines a consistent positive association between sense of ownership and sustainability of rural water systems. Second, despite 77% of beneficiaries stating that they were willing to pay for maintenance service, such contributions were not forthcoming, due to lack of trust in the water committee. In this scenario, almost 42% of the water points are reported as non-functional, 5–10 years after completion. 相似文献