High Swelling Research Articles

The role of stacking fault tetrahedra on void swelling in irradiated copper

A long-standing and critical issue in the field of irradiated structural materials is that void swelling is significantly higher in face-centered cubic-structured (fcc) materials (1% dpa−1) as compared to that of body-centered cubic-structured (bcc) materials (0.2% dpa−1). Despite extensive research in this area, the underlying mechanism of the difference in swelling resistance between these two types of materials is not yet fully understood. Here, by combining atomistic simulations and STEM imaging, we find stacking fault tetrahedra (SFTs) are the primary cause of the high swelling rate in pure fcc copper. We reveal that SFTs in fcc copper are not neutral sinks, different from the conventional knowledge. On the contrary, they are highly biased compared to other types of sinks because of the SFT-point defect interaction mechanism. SFTs show strong absorption of mobile self-interstitial atoms (SIAs) from the faces and vertices, and weak absorption of mobile vacancies from the edges. We compare the predicted swelling rates with experimental findings under varying conditions, demonstrating the distinct contributions of each type of sink. These findings will contribute to understanding the swelling of irradiated structural materials, which may facilitate the design of materials with high swelling resistance.

Multihydrogen Bond Modulated Polyzwitterionic Removable Adhesive Hydrogel with Antibacterial and Hemostatic Function for Wound Healing.

Wound management is a major challenge worldwide, placing a huge financial burden on the government of every nation. Wound dressings that can protect wounds, accelerate healing, prevent infection, and avoid secondary damage continue to be a major focus of research in the health care and clinical communities. Herein, a novel zwitterionic polymer (LST) hydrogel incorporated with [2-(methacryloyloxy) ethyl] dimethyl-(3-sulfopropyl) ammonium hydroxide (SBMA), mussel-inspired N-[tris(hydroxymethyl)methyl] acrylamide (THMA), and lithium magnesium salt was prepared for functional wound dressings. The incorporation of the THMA monomer containing three hydroxyl groups gives the hydrogel suitable adhesion properties (∼6.0 KPa). This allows the LST zwitterionic hydrogels to bind well to the skin, which not only protects the wound and ensures its therapeutic efficacy but also allows for painless removal and reduced patient pain. Zwitterionic sulfobetaine units of SBMA provide antimicrobial and mechanical properties. The chemical structure and microscopic morphology of LST zwitterionic hydrogels were systematically studied, along with their swelling ratio, adhesion, and mechanical properties. The results showed that the LST zwitterionic hydrogels had a uniform and compact porous structure with the highest swelling and mechanical strain of 1607% and 1068.74%, respectively. The antibacterial rate of LST zwitterionic hydrogels was as high as 99.49%, and the hemostatic effect was about 1.5 times that of the commercial gelatin hemostatic sponges group. In further studies, a full-thickness mouse skin model was selected to evaluate the wound healing performance. Wounds covered by LST zwitterionic hydrogels had a complete epithelial reformation and new connective tissue, and its vascular regenerative capacity was increased to about 2.4 times that of the commercial group, and the wound could completely heal within 12-13 days. This study provides significant advances in the design and construction of multifunctional zwitterionic hydrogel adhesives and wound dressings.

Nitric oxide-releasing photocrosslinked chitosan cryogels

The highly porous morphology of chitosan cryogels, with submicrometric-sized pore cell walls, provides a large surface area which leads to fast water absorption and elevated swelling degrees. These characteristics are crucial for the applications of nitric oxide (NO) releasing biomaterials, in which the release of NO is triggered by the hydration of the material. In the present study, we report the development of chitosan cryogels (CS) with a porous structure of interconnected cells, with wall thicknesses in the range of 340–881 nm, capable of releasing NO triggered by the rapid hydration process. This property was obtained using an innovative strategy based on the functionalization of CS with two previously synthesized S-nitrosothiols: S-nitrosothioglycolic acid (TGA(SNO)) and S-nitrosomercaptosuccinic acid (MSA(SNO)). For this purpose, CS was previously methacrylated with glycidyl methacrylate and subsequently submitted to photocrosslinking and freeze-drying processes. The photocrosslinked hydrogels thus obtained were then functionalized with TGA(SNO) and MSA(SNO) in reactions mediated by carbodiimide. After functionalization, the hydrogels were frozen and freeze-dried to obtain porous S-nitrosated chitosan cryogels with high swelling capacities. Through chemiluminescence measurements, we demonstrated that CS-TGA(SNO) and CS-MSA(SNO) cryogels spontaneously release NO upon water absorption at rates of 3.34 × 10−2 nmol mg−1 min−1 and 1.27 × 10−1 nmol mg−1 min−1, respectively, opening new perspectives for the use of CS as a platform for localized NO delivery in biomedical applications.

Antibacterial Komagataeibacter hansenii nanocellulose membranes with avocado seed bioactive compounds

AbstractBiocompatible, mechanically stable, highly hydrophilic/swellable and safe antibacterial biomaterials are crucial for wound dressing and other applications in the health sector. Therefore, this study was conducted for the development of bacterial nanocellulose membranes, which were, for the first time, enriched with bacteriostatic and bactericidal effective avocado seed extracts prepared by different extraction techniques (ultrasonic, Soxhlet, high pressure with supercritical carbon dioxide). First, the production process of bacterial nanocellulose membranes from Komagataeibacter hansenii bacteria was optimized related to the fermentation media composition and culture conditions, resulting in bacterial nanocellulose membranes with up to 83% crystallinity and 54.5 g/L yield. The morphological structure of the membranes was varied further by using air- and freeze-drying processes. The Soxhlet and high pressure with supercritical carbon dioxide avocado seed extracts with the most charge negative surface (-33 mV) and smallest hydrodynamic size (0.1 µm) thus resulted in 100% reduction of both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus with up to log reduction of 2.56 and up to 100% bactericidal efficacy after 24 h of exposure, and at 14 mg/g of avocado seed extracts integrated in the bacterial nanocellulose membranes homogeneously. The high swelling (up to 600%) and water retention ability of avocado seed extracts enriched bacterial nanocellulose membranes, with a biocidal release up to 2.71 mg/mL, shows potential for antibacterial applications in the biomedicine, cosmetics, and pharmaceutical industries.

Magnetic and PEG-crosslinked poly(methyl acrylate) functionalized with triethylenetetramine for removal of lead ions from contaminated water

A new magnetic polymer adsorbent with high swellability was prepared based on a PEG-crosslinked poly(methyl acrylate) via ATRP technique. FT-IR, TGA, CHN, FE-SEM, EDX, XRD, VSM, BET, and DLS measurements were used for the characterization of the prepared adsorbent. After replacing terminal bromines with triethylenetetramine chelating agent, the adsorption process of lead ions led to the removal of these ions from aqueous solutions. The removal of lead ions was investigated using ICP-OES technique. At pH = 7, the equilibrium adsorption capacity increased significantly and reached 37 mg/g at a contact time of 60 min. The adsorption capacity increased with increasing adsorption temperature (up to 40 °C) and initial concentration of lead ions (up to 70 mg/L), while it decreased with increasing adsorbent dose. The Freundlich isotherm better described the process of adsorption of lead ions by the prepared adsorbent. The adsorption kinetic was in greater agreement with pseudo-second-order model. The prepared adsorbent performed much better in adsorbing lead ions compared to cobalt and mercury ions. By performing the adsorption–desorption process three times, it was found that the adsorbent has high reusability. Overall, high swelling behavior and ease of magnetizability are two prominent features of the newly prepared adsorbent.

TENOFOVIR DISOPROXIL FUMARATE RELEASE FROM GLUTARALDEHYDE CROSS-LINKED CHITOSAN/Β-CYCLODEXTRIN HYDROGEL

In this study, chitosan was produced from crayfish Astacus leptodactylus, and then it was used to synthesize chitosan-graft-β-cyclodextrin (CS-g-β-CD) hydrogel. The produced chitosan (CS) and the sythesized CS-g-β-CD hydrogel were characterized using a Fourier Transform Infrared Spectroscopy (FTIR), Proton Nuclear Magnetic Resonance Spectroscopy (1H-NMR), X-ray Diffraction (XRD), and Scanning Electron Microscopy (SEM). Tenofovir disoproxil fumarate (TDF) was used as a model to investigate the antiviral drug release properties of the CS-g-β-CD hydrogel. The synthesized hydrogel had an almost homogeneous pore structure and a high swelling capacity which increases depending on the amount of β-Cyclodextrin (β-CD). The drug-loaded CS-g-β-CD hydrogels was examined by XRD and 1H-NMR, and SEM analyses. Seventy-three percent of the TDF loaded on the synthesized hydrogels was released into phosphate-buffered saline (PBS) solution at 37 ºC. The drug release behavior of all prepared CS-g-β-CD hydrogels fitted the Korsmeyer-Peppas model. The addition of β-CD into the gel improved the swelling ability and TDF release of the CS-g-β-CD hydrogel system.

Mobility of water and ions in partially water-saturated compacted MX-80 bentonite in relation with swelling pressure

Many countries are planning to host long-lived high- and intermediate-level radioactive waste in disposal facilities sited in deep argillaceous formations. Bentonite, as a swelling material, is often chosen as engineered buffers due to its low permeability and high swelling capacity. However, its properties can be influenced by the hydraulic/gas conditions prevailing in-situ that are expected to change throughout the duration of the repository. The objective of this work is to estimate the effect of partially water-saturated conditions on the mobility of water and ions in compacted MX-80 bentonite in relation to the evolution of its swelling pressure. For that purpose, (i) diffusion of water and ions (I− and Na+) and (ii) the swelling pressure of compacted bentonite samples partially water-saturated were studied by means of the osmotic technique that allows controlling the suction from 9 to 0 MPa.Results showed that (i) water diffusivity remained unchanged independently of the degrees of saturation (70, 84 and 100%) and (ii) iodide diffusivity decreased by a factor of 12 (from 100 to 70%), while (iii) Na+ diffusion was reduced by a factor of more than 70 (from 100 to 70%), associated to a drop of the distribution factor by a factor of 16. Comparison of these results with diffusion data already acquired in clayey materials whose porous structure evolves little with suction (i.e. compacted kaolinite and intact Collovo-oxfordian clay-rocks) underlined how the bentonite porous structure whose organization evolved with the degree of saturation is a key parameter. This statement is supported by mechanical tests, which indicated a distinct evolution of the swelling pressure curves depending on the degree of saturation. At 70% saturation, mechanical tests indicate (i) a preservation of the large inter-aggregate porosity where water can diffuse in both vapor and liquid phases, and (ii) a final swelling pressure 1.5 to 2 times lower than at full water saturation, meaning that a part of swelling clay particles was not accessible to water ingress and so to 22Na+. Conversely, at 84 % and 100 % saturation, change in swelling pressure curves was explained by a collapse of bentonite inter-aggregate porosity, in favor of expanding the inter-particle and interlayer porosities where 22Na + diffusion is enhanced by surface diffusion phenomenon.

Bioavailability enhancement of sildenafil citrate via hydrogel-forming microneedle strategy in combination with cyclodextrin complexation

Sildenafil citrate (SIL) as a first-line treatment for erectile dysfunction is currently reported to have poor solubility and bioavailability. Moreover, SIL undergoes first-pass metabolism when taken orally and its injection can lead to discomfort. In this study, we introduce a novel transdermal delivery system that integrates hydrogel-forming microneedles with the inclusion complex tablet reservoir. The hydrogel-forming microneedle was prepared from a mixture of polymers and crosslinkers through a crosslinking process. Importantly, the formulations showed high swelling capacity (>400 %) and exhibited adequate mechanical and penetration properties (needle height reduction < 10 %), penetrating up to five layers of Parafilm® M (assessed to reach the dermis layer). Furthermore, to improve the solubility of SIL in the reservoir, the SIL was pre-complexed with β-cyclodextrin. Molecular docking analysis showed that SIL was successfully encapsulated into the β-cyclodextrin cavity and was the most suitable conformation compared to other CD derivatives. Moreover, to maximize SIL delivery, sodium starch glycolate was also added to the reservoir formulation. As a proof of concept, in vivo studies demonstrated the effectiveness of this concept, resulting in a significant increase in AUC (area under the curve) compared to that obtained after administration of pure SIL oral suspension, inclusion complex, and Viagra® with relative bioavailability > 100 %. Therefore, the approach developed in this study could potentially increase the efficacy of SIL in treating erectile dysfunction by being non-invasive, safe, avoiding first-pass metabolism, and increasing drug bioavailability.

3D Bioprinting-Based Dopamine-Coupled Flexible Material for Nasal Cartilage Repair.

Since 3D printing can be used to design implants according to the specific conditions of patients, it has become an emerging technology in tissue engineering and regenerative medicine. How to improve the mechanical, elastic and adhesion properties of 3D-printed photocrosslinked hydrogels is the focus of cartilage tissue repair and reconstruction research. We established a strategy for toughening hydrogels by mixing GelMA-DOPA (GD), which is prepared by coupling dopamine (DA) with GelMA, with HAMA, bacterial cellulose (BC) to produce composite hydrogels (HB-GD). HB-GD hydrogel scaffolds were characterized in vitro by scanning electron microscopy (SEM), Young's modulus, swelling property and rheological property tests. And biocompatibility and chondrogenic ability were tested by live/dead staining, DNA quantitative analysis and immunofluorescence staining. Combined with 3D bioprinting technology, mouse chondrocytes (ADTC5) were added to form a biological chain to construct an in vitro model, and the feasibility of the model for nasal cartilage regeneration was verified by cytology evaluation. With the increase of GD concentration, the toughness of the composite hydrogel increased (47.0 ± 2.7 kPa (HB-5GD)-158 ± 3.2 kPa (HB-20GD)), and it had excellent swelling properties, rheological properties and printing properties. The HB-GD composite hydrogel promoted the proliferation and differentiation of ATDC5. Cells in 3D printed scaffolds had higher survival rates (> 95%) and better protein expression than the encapsulated cultures. The HB-10GD hydrogel can be made into a porous scaffold with precise shape, good internal pore structure, high mechanical strength and good swelling rate through extrusion 3D printing. This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

High performance all lignin derived supercapacitors for energy storage applications

The development of next-generation sustainable energy storage devices is attracting a lot of attention. This study explores the potential use of lignin, a biopolymer typically considered a byproduct of the paper and pulp industry, as a starting material for producing hydrogels through chemical crosslinking. The resulting hydrogels are then evaluated for their efficacy as precursors for electrolyte and electrode preparation in the development of a supercapacitor. Several concentrations of lignin and crosslinker were evaluated to determine the optimal conditions for producing hydrogel electrolytes. The optimised hydrogels exhibited excellent properties, including high swelling capacity, an interconnected macroporous morphology, and structural integrity. The carbonisation of lyophilised lignin hydrogels produced lignin-derived carbon materials with tailored nanoporous honeycomb-like structures. The integration of chemically crosslinked lignin hydrogel electrolytes with lignin-derived carbon electrodes resulted in a sustainable supercapacitor with superior electrochemical properties. The resulting all-lignin-based supercapacitors demonstrated a capacitance of 40.7 F/g at 0.5 A/g current density, with a capacity retention of 60% at higher current densities. The results of this study highlight the promise of lignin-based materials as both electrodes and electrolytes for the creation of environmentally sustainable, high-performance supercapacitors.

Swelling behavior of calcium ion-crosslinked sodium alginate in an in vitro hemostatic tamponade model

Various types of hemostatic agents are used to manage bleeding in surgery. Many such agents are animal products, which carry the risk of secondary infection. The aim of this study is to develop a novel hemostatic agent from a non-animal source that quickly stops bleeding, is easy to use, and has no risk of infection.In this study, we synthesized calcium ion-crosslinked sodium alginate (Alg-Na/Ca) by partial substitution of Ca ions for Na ions in sodium alginate. We prepared 12 kinds of Alg-Na/Ca powders with different Ca mass ratios, molecular weights, M/G ratios and particle size distributions and measured their swelling ratio and the burst pressure generated. We found that Alg-Na/Ca began to swell immediately after contact with saline, especially Alg-Na/Ca at Ca mass ratios of 74.1–77.0 % showed a high swelling ratio after 2 min and a high burst pressure, over 200 % and 500 mmHg respectively. Also, there is a correlation between the swelling ratio after 2 min and the burst pressure. Our results suggest that, by optimizing the composition conditions, Alg-Na/Ca may be an effective hemostatic agent that could act as a tamponade by absorbing and swelling at a bleeding site to quickly achieve primary hemostasis.

Polysaccharide hydrogel containing silver nanoparticle@catechol microspheres with photothermal, antibacterial and anti-inflammatory activities for infected-wounds repair

Anti-infection hydrogels have recently aroused enormous attraction, particularly in the treatment of chronic wounds. Herein, silver nanoparticle@catechol formaldehyde resin microspheres (Ag@CFRs) were fabricated by one-step hydrothermal method and subsequently encapsulated in hydrogels which were developed by Schiff base reaction between aldehyde groups in oxidized hyaluronic acid and amino groups in carboxymethyl chitosan. The developed polysaccharide hydrogel exhibited microporous structure, high swelling capacity, favorable mechanical strength, enhanced tissue adhesion and photothermal activities. Additionally, the hydrogel not only ensured long-term and high-efficiency antibacterial performance (99.9 %) toward E. coli and S. aureus, but also realized superior cytocompatibility in vitro. Moreover, based on the triple antibacterial strategies endowed by chitosan, silver nanoparticles and the photothermal properties of catechol microspheres, the composite hydrogel exhibited excellent anti-infection function, significantly downregulated inflammatory factors (TNF-α and IL-1β) and promoted in vivo infected-wound healing. These results demonstrated that the polysaccharide hydrogel containing Ag@CFRs has great potential for infected-wounds repair.

Robust and Elastic Thermoresponsive Hydrogels with High Swelling Properties for Efficient Solar Water Purification

Robust and Elastic Thermoresponsive Hydrogels with High Swelling Properties for Efficient Solar Water Purification

A Comprehensive Review on Novel Polymer Biomaterials for Hydrogel-Based Drug Delivery System

Abstract: Hydrogel biomaterials, which are formed from polymers generated from either natural or synthetic sources, are characterized by their mechanical stability as well as their biological acceptability. Hydrogels are characterized by properties such as a high swelling index, biocompatibility, the ability to be easily manipulated, flexibility, and rapid degradation. Hydrogels are commonly used as drug carriers due to the fact that they are simple to produce and may be applied by themselves. Using hydrogels in drug delivery applications, where gel-based nanocarriers carry drug molecules to the area of interest in living tissues. The research community is interested in doing this because of the unique physical and chemical properties that hydrogels possess. It has been discussed that several new hydrogel-based solutions are being employed for the administration of drugs that are not taken orally. Hydrogel systems can be developed for use in either passive or active drug administration, making them suitable for a broad variety of settings and applications. In addition to possessing essential biocompatible properties, hydrogels are able to move freely within the human body without having any visible impact on the surrounding environment. The present review has been developed to examine novel concepts linked to hydrogels and their delivery mechanism. This is due to the fact that hydrogels possess qualities that are both unique and novel. In this article, the mechanics of drug delivery systems that are based on hydrogels are detailed. These processes include loading, releasing, and targeting. For these components, the development and investigation of cutting-edge hydrogel- based delivery systems is necessary.

Scalable phosphorylated cellulose production with improved environmental sustainability, crosslinkability and processability using 3D bioprinting for dye remediation

In the present work, phosphorylated cellulose (PC) gel has been produced following an environmentally benign approach using agro-based chemicals with improved yield. The PC gels produced were transparent, negatively charged with high consistency, charge content (1133.33 mmol/kg), degree of substitution (DS) of 0.183 and increased yield (>87 %). The XPS and EDS analysis confirms the covalently bonded phosphate groups at weight percent of 9.42 % and 11.01 %, respectively. The life cycle assessment (LCA) shows that PC gel production via the phosphorylation route is an ecologically favourable strategy compared with traditional TEMPO oxidation, resulting in 1.67 times lower CO2 emission. The rheological studies of PC gels show shear-thinning behaviour with improved 3D printability followed by heat-induced crosslinking of phosphate groups. The mechanistic insights for the condensation of phosphate to form a phosphoric ester group during cross-linking were evaluated through 31P solid-state NMR and XPS studies. Interestingly, the 3D-printed structures showed high structural stability under both compression and tensile load in both dry and wet conditions, with high water absorption (5408.33 %) and swelling capacity of 700 %. The structures show improved methylene blue (MB) remediation capabilities with a maximum removal efficiency of 99 % for 10–200 mg/L and more than seven times reusability. This work provides a green, facile and energy-efficient strategy for fabricating PCs with easy processability through additive manufacturing techniques for producing value-added products, opening up new avenues for high-performance applications.

Turmeric-Derived Nanoparticles Functionalized Aerogel Regulates Multicellular Networks to Promote Diabetic Wound Healing.

Regulation of excessive inflammation and impaired cell proliferation is crucial for healing diabetic wounds. Although plant-to-mammalian regulation offers effective approaches for chronic wound management, the development of a potent plant-based therapeutic presents challenges. This study aims to validate the efficacy of turmeric-derived nanoparticles (TDNPs) loaded with natural bioactive compounds. TDNPs can alleviate oxidative stress, promote fibroblast proliferation and migration, and reprogram macrophage polarization. Restoration of the fibroblast-macrophage communication network by TDNPs stimulates cellular regeneration, in turn enhancing diabetic wound healing. To address diabetic wound management, TDNPs are loaded in an ultralight-weight, high swelling ratio, breathable aerogel (AG) constructed with cellulose nanofibers and sodium alginate backbones to obtain TDNPs@AG (TAG). TAG features wound shape-customized accessibility, water-adaptable tissue adhesiveness, and capacity for sustained release of TDNPs, exhibiting outstanding performance in facilitating in vivo diabetic wound healing. This study highlights the potential of TDNPs in regenerative medicine and their applicability as a promising solution for wound healing in clinical settings.

RAFT agent effect on graft poly(acrylic acid) to polypropylene glycol fumarate phthalate

Understanding the physical and chemical properties of new-generation polymeric materials during the synthesis is very important in obtaining the desired product in design and production. Chemical, thermal, and physical parameters as well as degradation kinetics of the resins developed especially in recent years are the main stages that determine the polymer composition process that affects material selection. In this study, the potential to use RAFT agent (2-cyano-2-propyldodecyltrithiocarbonate, CPDT) in the synthesis of new polymers based on polypropylene fumarate phthalate has revealed important properties. To exemplify, the concentration of the RAFT agent affects the polymer-based mesh density associated with the yield of the product. Changes in swelling behavior and thermodynamic parameters of polymers synthesized in the presence of RAFT agent were observed. Chemical composition and stability characterizations of the synthesized grafted polymers were performed by FT-IR, 13C, 1H-NMR spectroscopy and TGA. The grafted polymers analyzed by SEM morphology were found to have hydrogel sorption potential showed signs of a loose surface and the formation of a layered and porous structure in comparison with the grafted polymers. The resulting compounds have a high swelling capacity and increased yield. At the same time, this study will shed light on the thermodynamic calculations of the graft polymers in order to determine or predicting the polymer composition.Graphical abstract

Hydrogels based on lignin extracted from cashew apple bagasse and its application in antimicrobial wound dressings

Hydrogels are versatile materials with a three-dimensional network structure that can retain water and release bioactive compounds. They have found applications in various fields, including agriculture, biomaterial synthesis, and pharmaceuticals. Incorporating natural antimicrobial compounds into hydrogels is a promising approach to developing non-toxic biomedical materials, particularly for wound healing dressings. It was evaluated the extraction and use of cashew apple bagasse lignin (CAB-Lig) due to its healing, anti-inflammatory, and antimicrobial properties for producing a hydrogel-based bandage. The extraction process involved acid and alkali treatments followed by precipitation. The antimicrobial potential of CAB-Lig was evaluated at different concentrations for formulating hydrogels. Hydrogels containing 0.1 % and 3 % lignin showed high swelling and liquid retention abilities. The 3 % lignin hydrogel exhibited effectiveness against Escherichia coli and Staphylococcus aureus. Incorporating CAB-Lig into the hydrogel structure improved its mechanical properties, making it more suitable for application as a bandage. Moreover, the extracted lignin showed low toxicity, indicating its safe use. A bandage was formulated by combining the CAB-Lig-based hydrogel with polyester, which possessed antimicrobial properties and demonstrated biocompatibility (L929 and HaCat cells). The results confirmed the potential of CAB-Lig for synthesizing hydrogels and dressings with antimicrobial properties, offering a sustainable solution for utilizing lignocellulosic biomass.

Construction of a Soft Antifouling PAA/PSBMA Hydrogel Coating with High Toughness and Low Swelling through the Dynamic Coordination Bonding Provided by Al(OH)3 Nanoparticles.

Marine biofouling, resulting from the adhesion of marine organisms to ship surfaces, has long been a significant issue in the maritime industry. In this paper, we focused on utilizing soft and hydrophilic hydrogels as a potential approach for antifouling (AF) coatings. Acrylic acid (AA) with a polyelectrolyte effect and N-(3-sulfopropyl)-N-(methacryloxyethyl)-N,N-dimethylammonium betaine (SBMA) with an antipolyelectrolyte effect were selected as monomers. By adjusting the monomer ratio, we were able to create hydrogel coatings that exhibited low swelling ratio in both fresh water and seawater. The Al(OH)3 nanoparticle, as a physical cross-linker, provided better mechanical properties (higher tensile strength and larger elongation at break) than the chemical cross-linker through the dynamic coordination bonds and plentiful hydrogen bonds. Additionally, we incorporated trehalose into the hydrogel, enabling the repair of the hydrogel network through covalent-like hydrogen bonding. The zwitterion compound SBMA endowed the hydrogel with excellent AF performance. It was found that the highest SBMA content did not lead to the best antibacterial performance, as bacterial adhesion quantity was also influenced by the charge of the hydrogel. The hydrogel with appropriate SBMA content being close to electrical neutrality exhibits the strongest zwitterionic property of PSBMA chains, resulting in the best antibacterial adhesion performance. Furthermore, the pronounced hydrophilicity of SBMA enhanced the lubrication of the hydrogel surface, thereby reducing the friction resistance when applied to the hull surface during ship navigation.

Parapharyngeal Abscess: A Model of Continuity and Contiguity Deep-Neck Space Infections: A Diagnostic Dilemma!

The aims of the present case report were to review, computed tomography (CT) scans, clinical signs, treatment, and outcome of parapharyngeal space infections. These infections remain an important health problem with significant risks of morbidity and mortality. The term parapharyngeal abscess or infection is composed of two different disorders: infection located in the posterior part of the PPS with no invasion into the parapharyngeal fat and the second disorder is when the infection involving the parapharyngeal fat may be termed parapharyngeal abscess or deep neck abscess. Diffusion into the mediastinum and other severe complications are frequent. A 59 year old male, presented with three days history of intermittent high grade fever and left neck swelling which was rapidly increasing in size and associated with stridor, odynophagia and neck pain. The infection and accumulation of purulent discharge extend into the pharyngomaxillary space and inferiorly is located at the greater cornu of the hyoid bone. Temporary tracheostomy for respiratory assistance was performed. The frequent co-existence of parapharyngeal abscess and peritonsillar abscess favours careful consideration of addition of tracheotomy to lateral cervicotomy. Parapharyngeal abscess are deep neck abscesses that are common and thorough knowledge of their complex anatomy and aetiologies is essential in their treatment. Urgent surgical drainage is therefore mandatory.