Cross-linking, also called tanning, improves mechanical properties of leather and also increases its enzymatic and thermal stability. As a final product, leather has an ultimate tensile strength (σ) of 8-25 MPa and an elongation at break (ε) of >30 %. Mycelium-based materials are a sustainable alternative to leather. Here, the effect of cross-linkers was assessed on mechanical properties of Schizophyllum commune mycelium sheets. To this end, glutaraldehyde and N-(3-dimethylaminopropyl)-N\'-ethylcarbodiimide (EDC) were used as well as extracts of Ligustrum vulgare leaves, and bark of Acacia mearnsii and Caesalpinia spinosa. Untanned sheets had a σ of 7.8 MPa and an ε of 15.2 %, while the best overall combination of strength and elasticity was obtained with 0.1 % glutaraldehyde with a σ of 11.1 MPa and an ε of 14.6 %. Cross-linking also increased enzymatic stability and reduced mycelial water absorption but did not result in increased thermal stability. Fourier transform infrared spectroscopy (FTIR), 1D nuclear magnetic resonance spectroscopy (NMR), and amino acid analysis showed that glutaraldehyde bound both protein amino groups and polysaccharide hydroxyl groups by forming Schiff bases and acetals, respectively. Together, synthetic and vegetable cross-linkers can be used to obtain mycelium materials with leather-like tensile strength.

Synthesis of novel agro-industrial wastes/sodium alginate/bovine gelatin-based polysaccharide hydrogel beads, micromeritic/morphometric characteristics of the prepared formulations, greenhouse trials using controlled-release microencapsulated fertilizers, and acute fish toxicity testing were conducted simultaneously for the first time within the scope of an integrated research. In the present analysis, for the first time, 16 different morphometric features, and 32 disinct plant growth traits of the prepared composite beads were explored in detail within the framework of a comprehensive digital image analysis. The hydrogel beads composed of 19 different agro-industrial wastes/materials were successfully synthesized using the ionotropic external gelation technique and CaCl2 as cross-linker. According to micromeritic characteristics, the ionotropically cross-linked beads exhibited 77.86 ± 3.55 % yield percentage and 2.679 ± 0.397 mm average particle size. The dried microbeads showed a good swelling ratio (270.02 ± 80.53 %) and had acceptable flow properties according to Hausner\'s ratio (1.136 ± 0.028), Carr\'s index (11.94 ± 2.17 %), and angle of repose (25.03° ± 5.33°) values. The settling process of the prepared microbeads was observed in the intermediate flow regime, as indicated by the average particle Reynolds numbers (169.17 ± 82.81). Experimental findings and non-parametric statistical tests reveal that dried fertilizer matrices demonstrated noteworthy performance on the cultivation of red hot chili pepper plant (Capsicum annuum var. fasciculatum) according to the results of greenhouse trials. Surface morphologies of the best-performing fertilizer matrices were also characterized by Scanning Electron Microscopy. Moreover, the static fish bioassay experiment confirmed that no abnormalities and acute toxic reactions occurred in shortfin molly fish (Poecilia sphenops) fed with dried leaves of red hot chili pepper plants grown with formulated fertilizers. This study showcased a pioneering investigation into the synthesis of microcapsules using synthesized hydrogel beads along with digital image processing for bio-waste management and sustainable agro-application.

A combination of maleic acid and sodium hypophosphite as a durable press finishing agent has been reported as a safer but equally effective alternative to conventional formaldehyde-based cross-linking agents for applications in cellulose-based fiber and textile finishing. However, the mechanistic details of this system have not yet been fully elucidated to allow optimization of the conditions. Effective cross-linking treatment requires high curing temperatures of ≥160 °C, which enhances oxidative and thermal degradation of cellulose. In this work, the sequential steps of the cross-linking mechanism were investigated both with model compounds and cellulosic substrates. Extensive NMR studies on model compounds revealed several side reactions alongside the synthesis of the targeted cross-linkable moiety. As an alternative, to circumvent side reactions, a two-step procedure was used by synthesizing the cross-linker sodium 2-[(1,2-dicarboxyethyl)phosphinate]succinic acid in a well-defined pre-condensation reaction before application onto the cellulosic substrate. Further, the effect of the cross-linking treatment on the molecular weight distribution of cellulose was studied by gel permeation chromatography, which showed degradation due to maleic acid/sodium hypophosphite treatment. By using sodium 2-[(1,2-dicarboxyethyl)phosphinate]succinic acid and sodium hypophosphite, this degradation could be significantly limited.

The recovery of gold (Au) from electronic waste (e-waste) has gained significant attention due to its high Au content and economic feasibility compared to natural ores. This study presents a facile, single-step approach to prepare the chitosan-thioglycolic acid composite crosslinked with glutaraldehyde (CS-TGA-GA) and demonstrates its unique capability for precious metal management, which is a less investigated application area for thiolated chitosan materials. The novel cost-effective biosorbent CS-TGA-GA demonstrated a very high adsorption capacity of 1351.9 ± 96 mg/g and selectivity for Au(III) from an acidic e-waste solution at pH 1 and 298 K. The high adsorption capacity and selectivity of the sorbent can be attributed to the abundance of -NH2, -OH, and -SH groups present on its surface. Various characterizations, such as scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffractometry, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy, as well as sorption experiments, including pH, kinetic, and isotherm studies, were performed. The kinetic data align with a pseudo-second-order model and the isotherm data can be well expressed by the Freundlich model. The CS-TGA-GA composite effectively facilitated the conversion of Au(III) to Au(0), leading to the formation of Au nanoparticles that aggregated in the reaction vessel over time. Subsequently, the Au-loaded CS-TGA-GA underwent an incineration procedure, yielding recovered Au with a purity of 99.6%, as measured by X-ray fluorescence. In addition to its large uptake capacity, acid stability, and recyclability, the prepared sorbent showed a highly selective uptake of Au(III) ions in a solution containing various metal ions leached from waste printed circuit boards. These results highlight the potential of CS-TGA-GA as an adsorbent for the recovery of Au from e-waste leachate, thereby contributing to sustainable resource management.

Effective enzyme stabilization through immobilization is essential for the functional usage of enzymatic reactions. We propose a new method for synthesizing elastic hydroxyapatite microgel (E-HAp-M) materials and immobilizing lipase using this mesoporous mineral via the ship-in-a-bottle-neck strategy. The physicochemical parameters of E-HAp-M were thoroughly studied, revealing that E-HAp-M provides efficient space for enzyme immobilization. As a model enzyme, lipase (LP) was entrapped and then cross-linked enzyme structure, preventing leaching from mesopores, resulting in highly active and stable LP/E-HAp-M composites. By comparing LP activity under different temperature and pH conditions, it was observed that the cross-linked LP exhibited improved thermal stability and pH resistance compared to the free enzyme. In addition, they demonstrated a 156% increase in catalytic activity compared with free LP in hydrolysis reactions at room temperature. The immobilized LP maintained 45% of its initial activity after 10 cycles of recycling and remained stable for over 160 days. This report presents the first demonstration of a stabilized cross-linked LP in E-HAp-M, suggesting its potential application in enzyme-catalyzed processes within biocatalysis technology.

UNASSIGNED: Equipped with a photosynthetic apparatus that uses the energy of solar radiation to fuel biosynthesis of organic compounds, chloroplasts are the metabolic factories of mature leaf cells. The first steps of energy conversion are catalyzed by a collection of protein complexes, which can dynamically interact with each other for optimizing metabolic efficiency under changing environmental conditions.
UNASSIGNED: For a deeper insight into the organization of protein assemblies and their roles in chloroplast adaption to changing environmental conditions, an improved complexome profiling protocol employing a MS-cleavable cross-linker is used to stabilize labile protein assemblies during the organelle isolation procedure.
UNASSIGNED: Changes in protein:protein interaction patterns of chloroplast proteins in response to four different light intensities are reported. High molecular mass assemblies of central chloroplast electron transfer chain components as well as the PSII repair machinery react to different light intensities. In addition, the chloroplast encoded RNA-polymerase complex was found to migrate at a molecular mass of ~8 MDa, well above its previously reported molecular mass. Complexome profiling data produced during the course of this study can be interrogated by interested readers via a web-based online resource (https://complexomemap.de/projectsinteraction-chloroplasts).

OBJECTIVE: Corneal crosslinking (CXL) procedures are the treatment of choice in halting progressive corneal ectasia and preserving visual acuity due to keratoconus. Pulsed crosslinking (P-CXL) was developed using intermittent pulsing ultraviolet (UV) light to mitigate the depletion of oxygen levels that occurs with continuous UV exposure in standard crosslinking protocols (C-CXL). This study aimed to explore the use of P-CXL in the treatment of keratoconus and determine whether the availability of oxygen in P-CXL carries superior efficacy outcomes as an alternative to C-CXL modalities.
METHODS: This review was undertaken in accordance with PRISMA guidelines. A search of several databases conducted with two separate reviewers resulted in 29 papers meeting inclusion criteria for the review, 14 selected for meta-analysis. Primary outcomes assessed by the included papers included maximum keratometry (Kmax), corrected and uncorrected distance visual acuity (CDVA, UDVA), and secondary outcomes included central corneal thickness (CCT), endothelial cell count and demarcation line. Statistical analyses were carried out on Review Manager 5.4 and the meta-analysis employed a random-effects model, which estimated the weighted effect size of raw means using inverse variance weights.
RESULTS: At 12 months P-CXL showed statistically significant reductions in Kmax (-0.75 D; p < 0.001) and improvement in CDVA (-0.10 logMAR; p < 0.001) compared to baseline. The meta-analysis of comparative studies determined that mean differences in Kmax, CDVA, UDVA, Kmean and CCT after 12 months were not statistically significant between pulsed and continuous crosslinking groups.
CONCLUSIONS: Overall, P-CXL is effective in improving visual acuity and keratometry outcomes in keratoconus. The meta-analysis did not show a statistically significant difference in Kmax and CDVA between P-CXL and C-CXL, indicating a non-inferiority of P-CXL. However, findings of the meta-analysis are limited by the fact that different energy levels and exposure times were used for P-CXL in comparison to C-CXL in some studies, making it unsuitable to determine whether the efficacy of CXL is improved by the use of pulsed light.
CONCLUSIONS: What is Known • Pulsed crosslinking (P-CXL) uses intermittent UV light to prevent oxygen depletion when using higher energy protocols, unlike continuous UV exposure in standard continuous crosslinking (C-CXL). • This should theoretically enhance the efficacy of the treatment by maintaining higher oxygen levels that are crucial to the cross-linking process. • There are no systematic reviews or meta-analyses directly comparing the efficacy or safety of P-CXL to C-CXL. What is New • Meta-analysis revealed differences in keratometry between P-CXL and C-CXL groups with equivalent fluence (7.2 J/cm2) at 12 months were not statistically significant (Kmax -0.04 dioptres; p = 0.84). • Meta-analysis revealed differences in visual acuity between P-CXL and C-CXL groups with equivalent fluence (7.2 J/cm2) at 12 months were not statistically significant (CDVA -0.01 logMAR letters; p = 0.57). • The use of intermittent pulsing in higher energy CXL protocols renders statistically similar outcomes as continuous light exposure at equivalent fluence (7.2 J/cm2).

The mineralized collagen fibril is the main building block of hard tissues and it directly affects the macroscopic mechanics of biological tissues such as bone. The mechanical behavior of the fibril itself is determined by its structure: the content of collagen molecules, minerals, and cross-links, and the mechanical interactions and properties of these components. Advanced glycation end products (AGEs) form cross-links between tropocollagen molecules within the collagen fibril and are one important factor that is believed to have a major influence on the tissue. For instance, it has been shown that brittleness in bone correlates with increased AGEs densities. However, the underlying nano-scale mechanisms within the mineralized collagen fibril remain unknown. Here, we study the effect of mineral and AGEs cross-linking on fibril deformation and fracture behavior by performing destructive tensile tests using coarse-grained molecular dynamics simulations. Our results demonstrate that after exceeding a critical content of mineral, it induces stiffening of the collagen fibril at high strain levels. We show that mineral morphology and location affect collagen fibril mechanics: The mineral content at which this stiffening occurs depends on the mineral\'s location and morphology. Further, both, increasing AGEs density and mineral content lead to stiffening and increased peak stresses. At low mineral contents, the mechanical response of the fibril is dominated by the AGEs, while at high mineral contents, the mineral itself determines fibril mechanics.

Corneal ulcers are one of the most common ocular disorders in veterinary ophthalmology and several factors can negatively influence the efficacy of the currently available therapeutic options, leading to a loss of corneal transparency and, thus, vision. Twenty-five dogs with clinical signs of corneal ulcers were randomised to receive either corneal phototherapy (16 dogs; study group) or topical standard medical therapy (9 dogs; control group). The riboflavin/UV-A corneal phototherapy (PACK-CXL) consisted in the application of a riboflavin ophthalmic solution (Visioflavin®; Vision Engineering Italy srl, Rome, Italy) onto the cornea for 20 min followed by 30 mW/cm2 UV-A irradiance for 3 min using a point-of-care UV-A device (Vetuvir®; Vision Engineering Italy srl, Rome, Italy). The complete healing of the ulcerative lesion was defined as the complete restoration of the corneal epithelial integrity with negative fluorescein staining. The corneal phototherapy achieved complete corneal healing in all the dogs by 20.5 ± 7.8 days. In the control group, only two dogs achieved complete healing by 21.5 ± 15.6 days. This intervention may represent a valid option to hasten corneal wound healing and a clinical resolution of ulcerative keratitis in dogs.

Carbon molecular sieve (CMS) membranes have emerged as attractive gas membranes due to their tunable pore structure and consequently high gas separation performances. In particular, polyimides (PIs) have been considered as promising CMS precursors because of their tunable structure, superior gas separation performance, and excellent thermal and mechanical strength. In the present work, polyphosphoric acid (PPA) was employed as both cross-linker and porogen, it created pores within the PI polymeric matrix, while it also effectively acting as a cross-linker to regulate the ultramicropores of the CMS membranes, thus simultaneously improving both permeability and selectivity of the CMS membranes. By employing PI/PPA hybrid with PPA content of 5 wt % as a precursor, the obtained CMS membrane exhibited a CO2 and He permeability of 1378.3 Barrer and 1431.4 Barrer, respectively, which was an approximately 10-fold increase compared to the precursor membrane. Under optimized conditions, the CO2/CH4 and He/CH4 selectivity of the obtained CMS membrane reached 81.5 and 89.9, respectively, which was 278% and 307% higher than that of the pristine PI membrane. In addition, the membrane exhibited good long-term stability during a one-week continuous test. This study clearly denoted PPA can be used for precisely tailoring the ultramicroporosity of CMS membranes.