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To achieve efficient immobilization of papain (PAP), this study constructed a hydrophilic three-dimensional matrix for easy magnetic separation of the immobilized enzyme. The immobilization conditions were optimized using single-factor and response methodology. A core-shell structured nano-magnetic bead Fe3O4@PMMA was prepared by coating the magnetic Fe3O4 with poly(methyl methacrylate) (PMMA), followed by grafting polyethyleneimine (PEI) of different molecular weights. PAP was physically adsorbed onto the PEI, and then cross-linked using glutaraldehyde (GA) to construct an easily magnetically separable hydrophilic three-dimensional immobilization matrix Fe3O4@PMMA-PEI. The cross-linked encapsulation of PAP and its microstructure and physicochemical properties were characterized. Using the immobilization capacity of the nano-magnetic beads as the evaluation criterion, the optimal cross-linking time, glutaraldehyde concentration, cross-linking temperature, and cross-linking speed for immobilizing PAP were investigated. The results indicated that the carboxyl group content formed after the ester hydrolysis of the PMMA on the surface of the magnetic beads was 0.95 mmol/g. Following the grafting of PEI with different molecular weights, the amino group content on the surface of the magnetic beads was 0.16~0.48 mmol/g. The loading capacity of PAP on the nano-magnetic beads could be modulated by the molecular weight of the grafted PEI. When the molecular weight of PEI was 1800, the loading capacity reached 120.71 mg/g. PEI 1800 was selected as the grafting spacer arms. The nanomagnetic spheres exhibited well-defined morphology, uniform particle size distribution in the range of approximately 150~200 nm. Through response surface experiments, the best conditions were optimized: Cross-linking time of 32 minutes, glutaraldehyde concentration of 0.02%, cross-linking temperature of 25 ℃, and cross-linking speed of 90 revolutions per minute. Under these conditions, Fe3O4@PMMA-PEI 1800 achieved a PAP loading capacity of 139.80 mg/g. Importantly, even after five cycles of reuse, Fe3O4@PMMA-PEI 1800-PAP retained 80.35% of its relative enzyme activity. This study presents the design and synthesis of a nanomagnetic sphere structure tailored for the efficient immobilization of PAP, providing experimental evidence for the research and application of immobilized PAP.

The influence of epigallocatechin gallate (EGCG) on the physicochemical–rheological properties of silver carp surimi gel was investigated. The gel strength, texture, water-holding capacity (WHC), dynamic distribution of water, and rheological properties of surimi gels added with different levels (0, 0.02, 0.04, 0.06, 0.08, and 0.1%) of EGCG were measured. The results showed that with the increase of EGCG content, the gel strength, hardness, WHC, and immobilized water contents of surimi gels showed a trend of first increasing and then decreasing, and EGCG 0.02% and EGCG 0.04% showed better gel performance as compared with the control. EGCG 0.02% had the highest gel strength (406.62 g·cm), hardness (356.67 g), WHC (64.37%), and immobilized water contents (98.958%). The gel performance decreased significantly when the amounts of EGCG were higher than 0.06%. The viscosity, G′, and G″ of the rheological properties also showed the same trends. The chemical interaction of surimi gels, secondary structure of myofibrillar protein (MP), and molecular docking results of EGCG and silver carp myosin showed that EGCG mainly affected the structure and aggregation behavior of silver carp myosin through non-covalent interactions such as those of hydrogen bonds, hydrophobic interactions, and electrostatic interactions. The microstructures of EGCG 0.02% and EGCG 0.04% were compact and homogeneous, and had better gel formation ability. The lower concentrations of EGCG formed a large number of chemical interactions such as those of disulfide bonds and hydrophobic interactions inside the surimi gels by proper cross-linking with MP, and also increased the ordered β-sheet structure of MP, which facilitated the formation of the compact three-dimensional network gel.

In order to improve the hydrophobicity of tapioca starch, and used it as a granular emulsifier to improve the emulsification properties of myofibrillar protein (MP). In this study, a hydrophobic modification of native tapioca starch (NTS) by octenyl succinate anhydride (OSA), which produced ocentyl succinic tapioca starch (OSTS) with different modification levels and degrees of substitution (DS), and the compound emulsions were prepared using OSTS and MP. The structural changes of the OSTS were analyzed by XRD, FT-IR, SEM, and PLM, and the emulsion index (EI), emulsifying activity index (EAI), emulsion stability index (ESI), Zeta-potential, particle size distribution, sulfhydryl content, and interface protein content of the emulsions were determined. The results showed that the hydrophobic groups were successfully introduced in the tapioca starch molecules, and the hydrophobic modification treatment had basically no effect on the crystal structure type of the tapioca starch particles. The EAI and ESI of the OSTS-MP compound emulsions improved significantly (P

Abstract Objectives To investigate the short- and long-term effects of myopia control spectacle lenses with highly aspherical lenslets (HAL) and slightly aspherical lenslets (SAL) on visual function and visual quality using data obtained from a randomized controlled clinical trial. Methods This was a prospective, randomized, controlled, and double-blinded study; 170 myopic children aged 8–13 years were randomly assigned to the HAL, SAL, or single-vision spectacle lenses (SVL) groups. Distance and near visual acuity (VA) at high (100%) and low (10%) contrast in photopic and scotopic conditions, near phoria, stereoacuity, and accommodative lag, microfluctuations (AMFs), amplitude (AA) were measured after wearing lenses for 10 min, 6 months, and 12 months. Results In total, 161 subjects completed all follow-up in 12 months and were included in the analysis. After 10 min of wearing, the HAL and SAL groups had lower scotopic and low-contrast VA than the SVL group (decreased 0.03–0.08 logMAR and 0.01–0.04 logMAR in different VAs in the HAL and SAL groups, respectively, all P 0.05). The HAL and SAL groups had significantly larger AMFs than the SVL group (HAL vs. SAL vs. SVL: 0.21 ± 0.08 D vs. 0.16 ± 0.05 D vs. 0.15 ± 0.06 D at baseline, 0.19 ± 0.07 D vs. 0.17 ± 0.05 D vs. 0.13 ± 0.07 D at 12 months, all P 0.05). The HAL and SAL groups had reduced stereoacuity compared to the SVL group at baseline (70’ vs. 60’ vs. 50’, P = 0.005), but no difference was observed at 12 months (70’ vs. 70’ vs. 70’, P = 0.11). Conclusions HAL and SAL have no significant influence on accommodation and phoria except had larger AMF than SVL. Scotopic VA and low-contrast VA are reduced with short-term HAL and SAL use but recovered to be at same level with the SVL after 1 year of use. Trial registration Chinese Clinical Trial Registry: ChiCTR1800017683. Registered on 9 August 2018. http://www.chictr.org.cn/showproj.aspx?proj=29789

PurposeTo assess the precision and reliability of a novel computerized heterophoria test (CHT).MethodsOne hundred and three subjects aged 20 to 48 (27.37 ± 5.15) were recruited from Wenzhou Medical University. All subjects with corrected spectacles were examined with CHT and a prism-neutralized objective cover test (POCT) in a randomized order. They were then re-examined with CHT within 1 week. Their heterophoria was measured at three different distances (3 m, 0.77 m and 0.4 m); the average was recorded after three consecutive measurements. Inter-examiner repeatability, intra-examiner repeatability of CHT and agreement between CHT and POCT were evaluated.ResultsThere was no significant difference among repeated measurements using CHT (all p > 0.05). The difference between POCT and CHT was statistically significant at three distances (all p

Strawberry (Fragaria x ananassa) is an economically and important fruit species that is grown extensively around the entire world. In this study, we obtained the complete chloroplast genome of F. x ananassa. The chloroplast genome of F. x ananassa is 155,529 bp in size, containing a large single-copy region (85,523 bp), a small single-copy region (18,136 bp) and a pair of IR regions (each one of 25,935 bp). The overall GC contents of the chloroplast genome is 37.2%. The chloroplast genome of F. x ananassa contains 135 genes, including 90 protein-coding genes, 37 tRNA genes, and eight rRNA genes. The phylogenetic maximum-likelihood (ML) tree was constructed and based on 18 species plants and F. x ananassa chloroplast genomes, which F. x ananassa is closest related to Fragaria vesca subsp. vesca in phylogenetic relationship. This complete chloroplast genome can be further used for genomic studies, phylogenetic analyses, and genetic engineering studies of the genus Fragaria.