The impact of polypropylene‐graft‐maleic anhydride on the crystallization and dynamic mechanical properties of isotactic polypropylene

Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) were used to identify the mechanisms that lead to differences in the mechanical behavior of formulations of polypropylene blended with maleated polypropylene (MAPP) copolymers. MAPP lowered the melting temperature of PP indicating that less stable crystals were formed possibly because of cocrystallization of PP and MAPP. Crystallization kinetics revealed that copolymers do not change the rate of crystal growth, but may retard nucleation leading to a more spherulitic morphology. The dynamic storage modulus slightly increased in the glassy region with the small addition amounts of MAPP, while mechanical dampening systematically decreased with MAPP addition. An analysis of the viscoelastic behavior did not reveal any real differences in molecular coupling around the β‐transition of PP with the addition of the MAPP copolymer. At low addition levels, MAPP does not appear to have a significant impact on the viscoelastic properties of the polymer blend. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Hydrolysis of biliary phospholipids in the upper small intestine of the chick

Chick endogenous phospholipids were doubly labeled by an intravenous injection of [³²P] phosphate and [1-¹⁴C] oleic acid, and the free fatty acid and phospholipid fraction of gall bladder bile and in contents of upper small intestine were analyzed 4 days later. There was evidence of hydrolysis of biliary phosphatidylcholine to lysophosphatidylcholine in the duodenum and jejunum, but this did not account for the pronounced increase in the¹⁴C radioactivity of the free fatty acids relative to the³²P phospholipid radioactivity between bile and upper intestinal segments. It is suggested that phosphatidylcholine is largely absorbed in the duodenum of the chick while the remainder is progressively hydrolyzed and absorbed.     

COVID-19 Pandemic: Escape of Pathogenic Variants and MHC Evolution

We propose a new hypothesis that explains the maintenance and evolution of MHC polymorphism. It is based on two phenomena: the constitution of the repertoire of naive T lymphocytes and the evolution of the pathogen and its impact on the immune memory of T lymphocytes. Concerning the latter, pathogen evolution will have a different impact on reinfection depending on the MHC allomorph. If a mutation occurs in a given region, in the case of MHC allotypes, which do not recognize the peptide in this region, the mutation will have no impact on the memory repertoire. In the case where the MHC allomorph binds to the ancestral peptides and not to the mutated peptide, that individual will have a higher chance of being reinfected. This difference in fitness will lead to a variation of the allele frequency in the next generation. Data from the SARS-CoV-2 pandemic already support a significant part of this hypothesis and following up on these data may enable it to be confirmed. This hypothesis could explain why some individuals after vaccination respond less well than others to variants and leads to predict the probability of reinfection after a first infection depending upon the variant and the HLA allomorph.     

智能蓝光捕捉技术简述

为了防止有害光线对眼部的伤害,依视路集团研发出了智能蓝光捕捉技术,该技术可实现紫外线防护,符合新国标要求的蓝光防护,并维持色彩真实性。     

Megaprojects as complex adaptive systems: The Hinkley point C case

Megaprojects are complex projects which impact millions of people, involve public and private stakeholders, and present challenges related to decision making and performance shortfalls. They are relevant cases for studying faulty management thinking as well as performance evolutions and self-organizing dynamics. Our paper builds on the theory of Complex Adaptive Systems (CAS) to understand and model processes of evolution in the Hinkley Point C nuclear power plant megaproject. The results show that CAS properties apply to megaproject changes and provide a theoretical and practical framework for examining and modeling megaproject management dynamics. We designed a research methodology combining content analysis and historical research for its relevance in conducting organizational research in conditions of complexity and non-linearity. This original research design makes it possible to conduct causal analyses of relations between key megaproject events and thus build models of evolution dynamics in stakeholder success expectations, change mechanisms in the implementation of project outputs, and self-organizing patterns.     

The evolution of the exhaust diesel soot adsorptive properties after NO2 exposure and according to their SOF content

Several samples of exhaust diesel soot are investigated by inverse gas chromatography and linear solvation energy relationship (LSER) modelling according to their soluble organic fraction content and their time of exposure in oxidative conditions. The results demonstrate the evolution of the adsorptive properties of the studied materials towards volatile compounds during the oxidation under NO₂.     

Designs of 3-Dimensional Networks and MOFs Using Mono- and Polymetallic Copper(I) Secondary Building Units and Mono- and Polythioethers: Materials Based on the Cu–S Coordination Bond

This mini-review surveys 23 structures of 3D coordination polymers built upon mono-, di- as well as cyclic and acylic polythioethers. An emphasis is put on the Secondary Building Units (SBU) and the physical properties. Importantly, the key feature is that the dominant SBU is not the rhomboid (Cu₂X₂S₄), but an inorganic polymer containing at least the chain of the type (CuX) _n . In the latter type of SBU, these chain formations are observed for X = I, but predominantly for X = CN. In addition, a large portion of the surveyed materials exhibit rich photophysical properties, but on several occasions, these materials exhibit properties often attributed to MOFs, mainly solvent exchange.     

Weighted‐average isostrain and isostress model to describe the kinetic evolution of the mechanical properties of a composite gel: Application to the system gelatin:Maltodextrin

Application of a weighted‐average model (WAM) to the kinetic evolution of the elasticity during 16 h was successfully performed for a composite gel in which a maltodextrin phase is dispersed within a continuous gelatin phase. The results obtained using the model for different starting compositions along an initial higher‐temperature binodal are in good agreement with the phase diagram measured at high temperature and help to confirm the position of the binodal. A novel application of confocal Raman microscopy was used to measure the local concentration of the included phase of the composite gel and confirms the results given by the WAM. This model allows calculation of tie lines appropriate to the gel state and could be used for other biopolymer blends if the assumption is made that the gelation process involves a complete phase separation of both polymers before any gelation occurs. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1465–1477, 2000