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Critical assessment of structure prediction (CASP) conducts community experiments to determine the state of the art in computing protein structure from amino acid sequence. The process relies on the experimental community providing information about not yet public or about to be solved structures, for use as targets. For some targets, the experimental structure is not solved in time for use in CASP. Calculated structure accuracy improved dramatically in this round, implying that models should now be much more useful for resolving many sorts of experimental difficulties. To test this, selected models for seven unsolved targets were provided to the experimental groups. These models were from the AlphaFold2 group, who overall submitted the most accurate predictions in CASP14. Four targets were solved with the aid of the models, and, additionally, the structure of an already solved target was improved. An a posteriori analysis showed that, in some cases, models from other groups would also be effective. This paper provides accounts of the successful application of models to structure determination, including molecular replacement for X-ray crystallography, backbone tracing and sequence positioning in a cryo-electron microscopy structure, and correction of local features. The results suggest that, in future, there will be greatly increased synergy between computational and experimental approaches to structure determination.

CASP (Critical Assessment of Structure prediction) conducts communityexperiments to determine the state of the art in computing proteinstructure from amino acid sequence. The process relies on theexperimental community providing information about not yet public orabout to be solved structures, for use as targets. For some targets, theexperimental structure is not solved in time for use in CASP. Calculatedstructure accuracy improved dramatically in this round, implying thatmodels should now be much more useful for resolving many sorts ofexperimental difficulty. To test this, selected models for sevenunsolved targets were provided to the experimental groups. These modelswere from the AlphaFold2 group, who overall submitted the most accuratepredictions in CASP14. Four targets were solved with the aid of themodels, and, additionally, the structure of an already solved target wasimproved. An a-posteriori analysis showed that in some cases models fromother groups would also be effective. This paper provides accounts ofthe successful application of models to structure determination,including molecular replacement for X-ray crystallography, backbonetracing and sequence positioning in a Cryo-EM structure, and correctionof local features. The results suggest that in future there will begreatly increased synergy between computational and experimentalapproaches to structure determination.

Macromolecules of complex architecture find application as modifiers of commercial polymeric membrane materials. In this work, copolyimide molecular brushes (coPI) composed of polyimide backbone and poly(methacrylic acid) side chains were used to modify poly(m-phenylene iso-phthalamide) (PPA). Structure, physical, mechanical, and transport properties of dense nonporous PPA/coPI membranes containing up to 10 wt% coPI were studied. The effect of included coPI on the membrane structure was estimated using atomic force microscopy and mechanical tests. The coPI modifier contributes to the additional formation of free volume elements evenly distributed throughout the membrane. Transport properties of PPA/coPI membranes were investigated via sorption tests and pervaporation separation of methanol (MeOH) and methyl tert-butyl ether (MTBE) mixtures. The inclusion of coPI modifier in the PPA membrane leads to an increase in the total flux of the membrane. The highest separation factor was found for the PPA/coPI membrane containing 10 wt% coPI; transport properties of the best membrane were compared with the literature data on separation of the azeotropic MeOH-MTBE mixture. [ABSTRACT FROM AUTHOR]

In this paper, we report on novel polyimide (PI) nanocomposites filled with binary mixtures of metal oxide (either TiO2 or ZrO2) nanoparticles and nanocarbon (either carbon nanofibers (CNFs) or functionalized carbon nanotubes (CNTfs)). The structure and morphology of the materials obtained were comprehensively studied. An exhaustive investigation of their thermal and mechanical properties was performed. We revealed a synergistic effect of the nanoconstituents with regard to a number of functional characteristics of the PIs compared with single-filler nanocomposites, including thermal stability, stiffness (below and above glass transition temperature), yield point, and temperature of flowing. Moreover, the possibility of manipulating the properties of the materials by choosing a proper combination of the nanofillers was demonstrated. The results obtained can become a platform in the design of PI-based engineering materials with tailored characteristics capable of operating in extreme conditions. [ABSTRACT FROM AUTHOR]

It is known that structure of the interface between inorganic nanoparticles and polymers significantly influences properties of a polymer-inorganic composite. At the same time, amount of experimental researches on the structure and properties of material near the inorganic-polymer interface is low. In this work, we report for the first time the investigation of nanomechanical properties and maps of adhesion of material near the inorganic-polymer interface for the polyheteroarylene nanocomposites based on semi-crystalline poly[4,40-bis (4"-aminophenoxy)diphenyl]imide 1,3-bis (30,4-dicarboxyphenoxy) benzene, modified by ZrO2 nanostars. Experiments were conducted using quantitative nanomechanical mapping (QNM) mode of atomic force microscopy (AFM) at the surface areas where holes were formed after falling out of inorganic particles. It was found that adhesion of AFM cantilever to the polymer surface is higher inside the hole than outside. This can be attributed to the presence of polar groups near ZrO2 nanoparticle. QNM measurements revealed that polymer matrix has increased rigidity in the vicinity of the nanoparticles. Influence of ZrO2 nanoparticles on the structure and thermal properties of semi-crystalline polyheteroarylene matrix was studied with wide-angle X-ray scattering, scanning electron microscopy, and differential scanning calorimetry. [ABSTRACT FROM AUTHOR]

Mixed-matrix membranes based on amorphous and semi-crystalline polyimides with zirconium dioxide (ZrO2) nanostars were synthesized. Amorphous poly(4,40-oxydiphenylenepyromellitimide) and semi-crystalline polyimide prepared from 1,4-bis(4-aminophenoxy)benzene and 4,4'-oxydiphthalic anhydride were used. The effect of ZrO2 nanostars on the structure and morphology of nanocomposite membranes was studied by wide-angle X-ray scattering, scanning electron microscopy, atomic force microscopy, and contact angle measurements. Thermal properties and stability were investigated by thermogravimetric analysis and differential scanning calorimetry. Transport properties of hybrid membranes containing 5 wt % ZrO2 were tested for pervaporation of a mixture of butanol-water with 10 wt % H2 O content. It was found that a significant amount of the ZrO2 added to the semi-crystalline polyimide is encapsulated inside spherulites. Therefore, the beneficial influence of inorganic filler on the selectivity of mixed-matrix membrane with respect to water was hampered. Mixed-matrix membranes based on amorphous polymer demonstrated the best performance, because water molecules had higher access to inorganic particles. [ABSTRACT FROM AUTHOR]

Through an industry-science collaboration, a modified SELTRA codend consisting of a grid with scaring floats (GSF) was successfully developed by the fishing industry, and tested in a scientific trial on board a twin-rig demersal trawler. The selectivity of the gears used in the fishery needs to be tailored to each vessel and season, as quota availability differs across vessels and seasons. The modified gear aims at avoiding catching unwanted fish when targeting Norway lobster. The use of the modified codend showed good potential for effectively reducing catches of unwanted fish without affecting the catch of the target species Norway lobster. With respect to a standard SELTRA codend, the GSF design led to a significantly lower retention of unwanted fish, with 71 (61–79) % less cod, 94 (73–100) % less saithe and 22 (14–37) % less plaice being retained. The results show that fishers have the knowlegde to develop more selective gears. The authors argue that fisheries management should support such industry driven innovation through more flexible management approaches. • A modified SELTRA codend (GSF) was successfully developed by fishers. • The modified design led to a lower retention of cod, saithe and plaice. • There was no difference in catch efficiency of the target species Norway lobster. • More flexibility in management would help support industry's innovation. [ABSTRACT FROM AUTHOR]

The route for the preparation of cellulose nanofiber dispersions from bacterial cellulose using ethylene glycol- or glycerol-based deep eutectic solvents (DES) is demonstrated. Choline chloride was used as a hydrogen bond acceptor and the effect of the combined influence of DES treatment and ultrasound on the thermal and mechanical properties of bacterial cellulose nanofibers (BC-NFs) is demonstrated. It was found that the maximal Young's modulus (9.2 GPa) is achieved for samples prepared using a combination of ethylene glycol-based DES and ultrasound treatment. Samples prepared with glycerol-based DES combined with ultrasound exhibit the maximal strength (132 MPa). Results on the mechanical properties are discussed based on the structural investigations that were performed using FTIR, Raman, WAXD, SEM and AFM measurements, as well as the determination of the degree of polymerization and the density of BC-NF packing during drying with the formation of paper. We propose that the disordering of the BC-NF surface structure along with the preservation of high crystallinity bulk are the key factors leading to the improved mechanical and thermal characteristics of prepared BC-NF-based papers. [ABSTRACT FROM AUTHOR]