Fabrication of chitosan-based fluorescent hydrogel membranes cross-linked with bisbenzaldehyde for efficient selective detection and adsorption of Fe2.

Chitosan, as a natural biomass material, is green, recyclable, sustainable and well biocompatible. The molecular chain is rich in active groups such as amino and hydroxyl groups, and its preparation of fluorescent probes has the advantages of biocompatibility and efficient detection performance. In this study, a bis(benzaldehyde) (BHD) fluorescent functional molecule was designed. Then a series of fluorescent chitosan-based hydrogel films (CSBHD) were prepared using chitosan as raw material and BHD as cross-linking agent. As a fluorescent probe for metal ions, CSBHD was able to efficiently detect Fe2+ with a linear correlation of fluorescence intensity in the range of 0-160 µM, and the limit of detection (LOD) was 0.55 µM. Moreover, it has excellent adsorption performance for Fe2+ ions, with a maximum adsorption capacity of 223.5 g/mg at 500 mg/L Fe2+ concentration. Finally, we characterised the structure and microscopic morphology of CSBHD films and found that CSBHD as a hydrogel film has a high cross-linking density, good water resistance, excellent thermal stability, strong resistance to swelling, and excellent stability in cycling tests. Hence, it has great potential for application in adsorption and detection of Fe2+ ions. It also provides a good strategy for the application of chitosan based fluorescent probe materials in environmental monitoring and heavy metal ion adsorption.

MXene/Cellulose Hydrogel Composites: Preparation and Adsorption Properties of Pb2.

In this work, acrylic cellulose hydrogel, a typical natural polymer adsorbent, was modified using MXene through in situ polymerization to create a synthetic inorganic-polymer composite known as MXene/cellulose hydrogel. FTIR, XRD, SEM, and thermogravimetric analyses were applied to characterize the chemical structure and micromorphology. The MXene/cellulose hydrogel was utilized for the removal of Pb2+ from wastewater. Under optimal experimental conditions (initial Pb2+ concentration of 0.04 mol/L, adsorption time of 150 min, pH = 5.5, and MXene doping content of 50% at 30 °C), a maximum adsorption capacity of 410.57 mg/g was achieved. The MXene/cellulose hydrogel corresponded with the pseudo-second-order kinetic equation model and exhibited a better fit with the Freundlich isotherm model.

Preparation and performance study of rhodamine B naphthylamide, a fluorescent probe, for the detection of Fe3.

Fe3+ is essential for humans, and its deficiency or excess can be harmful to human health; thus, it is crucial to detect Fe3+. Herein, a novel 1,8-naphthylimide rhodamine-based fluorescent probe (NA-RhBEA) was prepared from rhodamine B, anhydrous ethylenediamine, and 1,8-naphthoic anhydride. This fluorescent probe complexes Fe3+ with N and O on the carboxyl groups of its spironolactam structure and part of the 1,8-naphthalenedicarboxylic anhydride structure, which results in spironolactam ring-opening and fluorescence. NA-RhBEA has high selectivity for Fe3+ in ethanol/buffer solution (4 : 1, v/v), and fluorescence is detected at an excitation wavelength λEX = 500 nm, an absorption peak appears at 585 nm, and a significant color change appears. The effect of the fluorescence intensity of Fe3+ under a series of different concentration conditions was investigated, and it was concluded that the fluorescence intensity increased with increasing Fe3+ concentration in the range of 0-500 µmol, and its detection limit was 0.84 µmol L-1. In addition, we explored the detection ability of NA-RhBEA in solutions with different pH values, mixed metal ions, and different solvents, and the results showed that the fluorescent sensor also has good anti-interference properties and some practical applicability.

Fabrication of 1,8-naphthalimide modified cellulose derivative composite fluorescent hydrogel probes and their application in the detection of Cr(VI).

The design and development of a rapid and quantitative method for the detection of heavy metal ions is of great importance for environmental protection. We have prepared a 1,8-Naphthalimide modified cellulose composite fluorescent hydrogel (CENAEA/PAA) with a stereo double network structure. Characterized by excellent hydrogel functional structure and fluorescence detection performance, it can efficiently and selectively identify and detect Cr(VI) with linear quenching in the range of 0-400 µmol/L and detection limit of 0.58 µmol/L for Cr(VI). The results show that the CENAEA/PAA can effectively adsorb Cr(VI) with a maximum adsorption capacity of 189.04 mg/g. Finally, the morphological characteristics, chemical structure, fluorescence properties and adsorption behavior of CENAEA/PAA were analyzed and fitted well with the pseudo-second-order model and Freundlich model. Thus, the present work provides a green and sustainable approach for the synthesis of a functional material that can be used for the detection and adsorption of heavy metal ions.

Photothermal Conversion of Hydrogel-Based Biomaterial.

Traditional energy from fossil fuels like petroleum and coal is limited and contributes to global environmental pollution and climate change. Developing sustainable and eco-friendly energy is crucial for addressing significant challenges such as climate change, energy dilemma and achieving the long-term development of human society. Biomass hydrogels, which are easily synthesized and modified, have diverse sources and can be designed for different applications. They are being extensively researched for their applications in artificial intelligence, flexible sensing, biomedicine, and food packaging. The article summarizes recent advances in the preparation and applications of biomass-based photothermal conversion hydrogels, discussing the light source, photothermal agents, matrix, and preparation methods in detail. It also explores the use of these hydrogels in seawater desalination, photothermal therapy, antibacterial agents, and light-activated materials, offering new ideas for developing sustainable, efficient, and advanced photothermal conversion biomass hydrogel materials. The article concludes with suggestions for future research, highlighting the challenges and prospects in this field and paving the way for developing of long-lasting, efficient energy materials.

Progress in preparation and properties of chitosan-based hydrogels.

Chitosan is a kind of natural polysaccharide biomass with the second highest content in nature after cellulose, which has good biological properties such as biocompatibility, biodegradability, hemostasis, mucosal adsorption, non-toxicity, and antibacterial properties. Therefore, hydrogels prepared from chitosan have the advantages of good hydrophilicity, unique three-dimensional network structure, and good biocompatibility, so they have received extensive attention and research in environmental testing, adsorption, medical materials, and catalytic supports. Compared with traditional polymer hydrogels, biomass chitosan-based hydrogels have advantages such as low toxicity, excellent biocompatibility, outstanding processability, and low cost. This paper reviews the preparation of various chitosan-based hydrogels using chitosan as raw material and their applications in the fields of medical materials, environmental detection, catalytic carriers, and adsorption. Some views and prospects are put forward for the future research and development of chitosan-based hydrogels, and it is believed that chitosan-based hydrogels will be able to obtain more valuable applications.

Preparation and Application of pH-Sensitive Film Containing Anthocyanins Extracted from Lycium ruthenicum Murr.

A new pH-sensitive film was developed using Artemisia sphaerocephala Krasch. gum (ASKG), soybean protein isolate (SPI), and natural anthocyanin extracted from Lycium ruthenicum Murr. The film was prepared by adsorbing anthocyanins dissolved in an acidified alcohol solution on a solid matrix. ASKG and SPI were used as the solid matrix for the immobilization of the Lycium ruthenicum Murr. anthocyanin extract, which was absorbed into the film as a natural dye using the facile-dip method. Regarding the mechanical properties of the pH-sensitive film, the tensile strength (TS) values increased approximately 2-5-fold, but the elongation at break (EB) values decreased significantly by about 60% to 95%. With the increase in anthocyanin concentration, the oxygen permeability (OP) values first decreased by about 85%, and then increased by about 364%. The water vapor permeability (WVP) values increased by about 63%, and then decreased by about 20%. Colorimetric analysis of the films revealed variations in color at different pH values (pH 2.0-10.0). Fourier-transform infrared (FT-IR) spectra and XRD patterns indicated compatibility among ASKG, SPI, and anthocyanin extracts. In addition, an application test was conducted to establish a correlation between film color change and carp meat spoilage. At storage temperatures of 25 °C and 4 °C, when the meat was totally spoiled, the TVB-N values reached 99.80 ± 2.53 mg/100 g and 58.75 ± 1.49 mg/100 g, and the film's color changed from red to light brown and from red to yellowish green, respectively. Therefore, this pH-sensitive film could be used as an indicator to monitor the freshness of meat during storage.

Biogenic methane in coastal unconsolidated sediment systems: A review.

Marine sediments are the world's largest known reservoir of methane. In many coastal regions, methane is trapped in sediments buried at depths ranging from centimeters to hundreds of meters below the seafloor, in the forms of gas pockets, dispersed gas bubbles and dissolved gas, also known as shallow gas (methane-dominated gas mixture). The existence of shallow gas affects the engineering geological environment and threatens the safety of artificial facilities. The escape of shallow gas from sediments into the atmosphere can even threaten ecosystem security and affect global climate change. However, until now, shallow gas has remained a mystery to the scientific community. For example, how it is generated, how it distributes and migrates in sediments, and what are the factors that influence these processes that are still unclear. In the context of increasingly intense offshore development and global warming, there is a huge gap between existing scientific understanding of shallow gas and the need to develop scientific solutions for related problems. Based on this, this paper systematically collects the information on all aspects of shallow gas mentioned above, comprehensively summarizes the current scientific understanding, and analyzes the existing shortcomings, which will provide systematic references for the research on environmental disaster prevention, engineering technology, climate change, and other fields.

Thermal and mechanical properties of coal gasification slag based foam concrete.

Foam concrete possesses low density and excellent thermal insulation properties and has been widely used in construction industry. Considering the recycling and reusing of coal gasification slag (CGS), a solid waste product in the coal chemical industry, CGS was used as the supplementary cementations material to prepare foam concrete (CGS-FC) in this work. The influence of the CGS content and water-binder ratio on the pore structure, mechanical and thermal properties was investigated. The results show that the CGS content and water-binder ratio directly impact the fluidity of the slurry, which affects the internal pore structure of the specimens after molding. And a CGS-FC with a compressive strength of 6.89 MPa, thermal conductivity of 0.24 W/m K, and a bulk density of 867 kg/m3 was successfully produced when the CGS content was 30% and water-binder ratio was 0.5. In particular, the utilization of CGS to prepare foam concrete product has recycling efficiency and environmental benefit.

Preparation and application of chitosan-based fluorescent probes.

Biomass materials have abundant natural resources, renewability and good biochemical compatibility, so biomass-based fluorescent materials prepared from biomass materials have gradually become a research hotspot. In particular, the low cost and environmentally friendly properties of chitosan have been widely used in the field of functional materials. Chitosan-based functional materials have attracted extensive attention in the detection and removal of organic and inorganic pollutants. They have been widely used in biological imaging, environmental detection, drug carriers and other fields. This paper reviews the preparation and application of chitosan-based fluorescent probes, including chitosan-derived fluorescent probe materials and chitosan-based carbon quantum dots. At the same time, it focuses on the application research of chitosan-based carbon quantum dots in the fields of environmental detection, cell imaging, drug carriers, photocatalysis, etc. In addition, it provides new ideas and application prospects for the development and application of chitosan-based fluorescent materials in the future.

Virtual navigation bronchoscopy-guided intraoperative indocyanine green localization in simultaneous surgery for multiple pulmonary nodules.

BACKGROUND: Accurate localization of pulmonary nodules is the main difficulty experienced in wedge resection. Commonly used localization methods have their own advantages and disadvantages. However, clinical work has demonstrated that intraoperative indocyanine green localization under electromagnetic navigation bronchoscopy/virtual navigation bronchoscopy (VNB) is more advantageous than conventional methods for patients with multiple pulmonary nodules undergoing simultaneous surgery, especially for those undergoing bilateral lung surgery. METHODS: Data of patients undergoing simultaneous surgery for multiple pulmonary nodules with preoperative methylene blue localization by computed tomography (CT)-guided percutaneous lung puncture (methylene blue group) or intraoperative indocyanine green localization under VNB (virtual navigation group) were retrospectively analyzed. Patient characteristics, pulmonary nodule features, localization time, preoperative location time, location success rate, operation time, complication incidence, visceral pleural staining rate after localization, and pulmonary nodule primary resection success rate were compared between the two groups. RESULTS: The methylene blue and virtual navigation groups comprised 39 and 20 patients with 119 and 67 pulmonary nodules resected, respectively. Sex, age, number of pulmonary nodules resected simultaneously, unilateral/bilateral lung surgery, pulmonary nodule size, distance between pulmonary nodules and the visceral pleura, pulmonary nodule consolidation-to-tumor ratio, location of pulmonary nodules in the pulmonary lobe, postoperative pathology, visceral pleura staining rate, primary pulmonary nodule resection success rate, and surgical duration did not differ significantly between the groups (p > 0.05). The localization time of the virtual navigation group was significantly shorter than that of the methylene blue group (p < 0.05), regardless of unilateral or bilateral multiple nodules. In the methylene blue group, 25.64% (10/39) of patients presented complications, all of which were pneumothorax, whereas no complications were found in the virtual navigation group. CONCLUSIONS: For patients with multiple pulmonary nodules undergoing simultaneous surgery, indocyanine green injection under VNB can achieve a similar effect on pulmonary nodule localization as classical methylene blue injection under CT-guided percutaneous lung puncture, with shorter localization time and fewer complications.

Resourceful Utilization of Cow Hair in the Preparation of Iron Tailing-Based Foam Concrete.

Cow hair, a by-product of tannery waste, is usually stockpiled on a large scale as waste, which leads to serious environmental impacts. In this paper, cow hair was used as a reinforcement fiber to improve the mechanical strength of iron tailing-based foam concrete. The effects of the amount of cow hair fiber on the apparent density, compressive strength, and flexural strength of foam concrete were investigated by a series of characterization methods. Meanwhile, Image-Pro Plus software was used to analyze the porosity, average pore size, roundness, and other parameters of the specimens with different amounts of cow hair fiber. Results revealed that a proper amount of cow hair fiber can form a stable three-dimensional network structure inside the foam concrete and promote a uniform distribution and size of the pore structure inside the test piece. This could effectively improve the compressive strength, flexural strength, and crack resistance of the foam concrete, and when the fiber content was 0.2 wt%, the foam concrete exhibited the best mechanical properties, with a compressive strength of 11.19 MPa and a flexural strength of 3.58 MPa. The present work was in agreement with the strategic objective of resource recycling and solid waste utilization, which was conducive to the development of the circular and green economy.

Effect of paeonol against bacterial growth, biofilm formation and dispersal of Staphylococcus aureus and Listeria monocytogenes in vitro.

Previous studies have demonstrated the antibacterial activity of paeonol against bacterial pathogens, but its anti-biofilm activities against Staphylococcus aureus and Listeria monocytogenes remain largely unexplored. Here, the antibacterial and anti-biofilm activities of paeonol against S. aureus and L. monocytogenes were examined using the crystal violet staining assay (CVSA), field emission scanning electron microscopy (FESEM), and confocal laser scanning microscopy (CLSM) analysis. Paeonol effectively inhibited the growth of S. aureus and L. monocytogenes with a minimum inhibitory concentration (MIC) of 500 and 125 µg ml-1, respectively, and disrupted the integrity of cell membranes. Moreover, sub-MIC paeonol exhibited an inhibitory effect on the attachment of S. aureus and L. monocytogenes to the abiotic surface and biofilm formation. Further, paeonol effectively destroyed cell membranes within biofilms, and dispersed mature biofilms of both strains. The results indicate that paeonol might be a promising antibacterial and anti-biofilm agent for combating infections caused by S. aureus and L. monocytogenes.

Safety and feasibility study of uniportal video-assisted thoracoscopic pulmonary wedge resection without postoperative chest tube drainage: a retrospective propensity score-matched study.

OBJECTIVES: The aim of this study was to assess the impact of postoperative chest tube drainage (CTD) on safety and postoperative recovery by comparing patients with pulmonary nodule undergoing uniportal video-assisted thoracoscopic pulmonary wedge resection with and without postoperative CTD. METHODS: We retrospectively analysed the data of patients who underwent video-assisted thoracoscopic pulmonary wedge resection for pulmonary nodule at our hospital between 2018 and 2022. In cases where a 12-Fr chest tube was used following the procedure, the tube was not usually removed until the day after surgery. Therefore, the eligible patients were categorized into the drainage tube or the no-drainage tube group according to the use of postoperative CTD. Propensity score matching at a ratio of 1:1 was performed using clinicopathologic and demographic variables. The highest postoperative pain score, postoperative complication rate, postoperative length of stay and hospitalization costs were compared between the 2 groups. RESULTS: A total of 275 eligible patients, including 150 and 125 patients in the drainage tube and no-drainage tube groups, respectively, were included in the study. After propensity score matching, there were 102 patients in each group. The postoperative complication rate during hospitalization and at 1 week and 1 month after discharge were not significantly different between the 2 groups (P > 0.05 for all). The highest postoperative pain score was significantly lower in the no-drainage tube group than in the drainage tube group [2.02 (standard deviation: 0.81) days vs 2.31 (standard deviation: 0.76) days, P = 0.008]. The postoperative length of stay was significantly shorter in the no-drainage tube group than in the drainage tube group {3.00 [interquartile ranges (IQRs): 2.00-4.00] days vs 2.00 (IQRs: 1.00-3.00) days, P < 0.001}. Similarly, the total hospitalization costs were significantly lower in the no-drainage tube group than in the drainage tube group [33283.74 (IQRs: 27098.61-46718.56) yuan vs 26598.67 (IQRs: 22965.14-29933.67) yuan, P < 0.001]. CONCLUSIONS: Omission of postoperative CTD was safe and feasible in patients with pulmonary nodule undergoing wedge resection. The no-postoperative-drainage policy can substantially shorten the length of hospital stay and reduce the postoperative pain and hospitalization costs without increasing the risk of postoperative complications.

Fabrication, Structure, Performance, and Application of Graphene-Based Composite Aerogel.

Graphene-based composite aerogel (GCA) refers to a solid porous substance formed by graphene or its derivatives, graphene oxide (GO) and reduced graphene oxide (rGO), with inorganic materials and polymers. Because GCA has super-high adsorption, separation, electrical properties, and sensitivity, it has great potential for application in super-strong adsorption and separation materials, long-life fast-charging batteries, and flexible sensing materials. GCA has become a research hotspot, and many research papers and achievements have emerged in recent years. Therefore, the fabrication, structure, performance, and application prospects of GCA are summarized and discussed in this review. Meanwhile, the existing problems and development trends of GCA are also introduced so that more will know about it and be interested in researching it.

Investigation of the Effects of Polymer Dispersants on Dispersion of GO Nanosheets in Cement Composites and Relative Microstructures/Performances.

This study focused on the uniform distribution of graphene oxide (GO) nanosheets in cement composites and their effect on microstructure and performance. For this, three polymer dispersants with different level of polar groups (weak, mild, and strong) poly(acrylamide-methacrylic acid) (PAM), poly(acrylonitrile-hydroxyethyl acrylate) (PAH), and poly(allylamine-acrylamide) (PAA) were used to form intercalation composites with GO nanosheets. The results indicated that GO nanosheets can exist as individual 1⁻2, 2⁻5, and 3⁻8 layers in GO/PAA, GO/PAH, and GO/PAM intercalation composites, respectively. The few-layered (1⁻2 layers) GO can be uniformly distributed in cement composites and promote the formation of regular-shaped crystals and a compact microstructure. The compressive strengths of the blank, control, GO/PAM, GO/PAH, and GO/PAA cement composites were 55.72, 78.31, 89.75, 116.82, and 128.32 MPa, respectively. Their increase ratios relative to the blank sample were 40.54%, 61.07%, 109.66%, and 130.29%, respectively. Their corresponding flexural strengths were 7.53, 10.85, 12.35, 15.97, and 17.68 MPa, respectively, which correspond to improvements of 44.09%, 64.01%, 112.09%, and 134.79%.

Fabrication of GO/Cement Composites by Incorporation of Few-Layered GO Nanosheets and Characterization of Their Crystal/Chemical Structure and Properties.

Original graphene oxide (GO) nanosheets were prepared using the Hummers method and found to easily aggregate in aqueous and cement composites. Using carboxymethyl chitosan (CCS) as a dispersant, few-layered GO nanosheets (1-2 layers) were obtained by forming CCS/GO intercalation composites. The testing results indicated that the few-layered GO nanosheets could uniformly spread, both in aqueous and cement composites. The cement composites were prepared with GO dosages of 0.03%, 0.05% and 0.07% and we found that they had a compact microstructure in the whole volume. A special feature was determined, namely that the microstructures consisted of regular-shaped crystals created by self-crosslinking. The X-ray diffraction (XRD) results indicated that there was a higher number of cement hydration crystals in GO/cement composites. Meanwhile, we also found that partially-amorphous Calcium-Silicate-Hydrate (C-S-H) gel turned into monoclinic crystals. At 28 days, the GO/cement composites reached the maximum compressive and flexural strengths at a 0.05% dosage. These strengths were 176.64 and 31.67 MPa and, compared with control samples, their increased ratios were 64.87% and 149.73%, respectively. Durability parameters, such as penetration, freeze-thaw, carbonation, drying-shrinkage value and pore structure, showed marked improvement. The results indicated that it is possible to obtain cement composites with a compact microstructure and with high performances by introducing CCS/GO intercalation composites.

The Adsorption Capacity of GONs/CMC/Fe3O4 Magnetic Composite Microspheres and Applications for Purifying Dye Wastewater.

Graphene oxide nanosheets (GONs)/carboxymethyl chitosan (CMC)/Fe3O4 magnetic composite microspheres (MCMs) were prepared by enclosing Fe3O4 particles with CMC and GONs in turn. The microstructures of GONs and GONs/CMC/Fe3O4 MCMs were characterized by FTIR, XRD, TEM, and SEM. The effects of GON content, pH value, and adsorption time on the adsorption capacity of the MCMs were investigated. The results show that the GONs/CMC/Fe3O4 MCMs have a greater specific surface area and a strong adsorption capacity for dye wastewater. Meanwhile, the adsorption mechanism was investigated, and the results accorded with the pseudo-second-order kinetic model and the Freundlich isotherm model. The search results indicate that GONs/CMC/Fe3O4 MCMs can be used to purify dye wastewater and has an important potential use in the practical purification of dye wastewater.

Preparation of Cement Composites with Ordered Microstructures via Doping with Graphene Oxide Nanosheets and an Investigation of Their Strength and Durability.

The main problem with cement composites is that they have structural defects, including cracks, holes, and a disordered morphology, which significantly affects their strength and durability. Therefore, the construction of cement composites with defect-free structures and high strength and long durability is an important research topic. Here, by controlling the size and chemical groups of graphene oxide nanosheets (GONs) used for doping, we were able to control the entire cement matrix to form an ordered microstructure consisting of polyhedron-like crystals and exhibit flower-like patterns. The cracks and holes in the cement matrix just about vanished. The compressive and flexural strengths as well as the parameters for the durability assessment of the corresponding cement composites obviously improved compared with the control samples. Thus, the formation mechanism of the cement matrix with the ordered microstructure is proposed, and a proper explanation is given to regulation action.

Synthesis of starch-g-p(DMDAAC) using HRP initiation and the correlation of its structure and sludge dewaterability.

A new cationic starch used as a sludge dewatering agent was prepared by grafting copolymerization of degradation starch and dimethyldiallylammonium chloride (DMDAAC) using horseradish peroxidase/H2O2 initiation. Its chemical structure was characterized by FTIR, (1)H NMR, (13)C NMR, gel permeation chromatography, graft percent, and graft efficiency. The results indicated that its structure was built by grafting the DMDAAC oligomer onto the starch backbone as branched chains, with stronger hydrophobic regions and higher cationic degree. The specific resistance of the filtration and capillary suction time of the sludge conditioned with the cationic starch decreased distinctly, and the sludge water content could be reduced to 50.6% from 97.85%. The dewatering mechanism is proposed based on the surface tension, zeta potential, and microstructure of sludge, which involves stronger hydrophobic regions and cationic groups producing a porous structure within the sludge. The research results may provide valuable ideas for developing high-performance sludge dewatering agents.