Self-Assembled Hydrogel Membranes with Structurally Tunable Mechanical and Biological Properties.

Using supramolecular self-assembled nanocomposite materials made from protein and polysaccharide components is becoming more popular because of their unique properties, such as biodegradability, hierarchical structures, and tunable multifunctionality. However, the fabrication of these materials in a reproducible way remains a challenge. This study presents a new evaporation-induced self-assembly method producing layered hydrogel membranes (LHMs) using tropocollagen grafted by partially deacetylated chitin nanocrystals (CO--ChNCs).

An eco-friendly, highly efficient, and transparent coating derived from guar gum and citric acid for flame retardant treatment of cotton fabrics.

A highly efficient, bio-ecofriendly, and transparent flame retardant (FR) for cotton fabric was developed and deposited onto the cellulose skeletal structure of cotton fabric through a one-pot sol-gel process. The flame retardant functional coating is composed of ammonium polyphosphate (APP), guar gum (GG), citric acid (CA), and a negligible amount of catalyst. Cotton fabrics were impregnated with different concentrations of ammonium polyphosphate and guar gum, with citric acid as a crosslinking agent.

Carboxymethyl starch as a reducing and capping agent in the hydrothermal synthesis of selenium nanostructures for use with three-dimensional-printed hydrogel carriers.

The hydrothermal method is a cost-effective and eco-friendly route for preparing various nanomaterials. It can use a capping agent, such as a polysaccharide, to govern and define the nanoparticle morphology. Elemental selenium nanostructures (spheres and rods) were synthesized and stabilized using a tailor-made carboxymethyl starch (CMS, degree of substitution = 0.

Marine Biomaterials: Hyaluronan.

The marine-derived hyaluronic acid and other natural biopolymers offer exciting possibilities in the field of biomaterials, providing sustainable and biocompatible alternatives to synthetic materials. Their unique properties and abundance in marine sources make them valuable resources for various biomedical and industrial applications. Due to high biocompatible features and participation in biological processes related to tissue healing, hyaluronic acid has become widely used in tissue engineering applications, especially in the wound healing process.

The Effects of the Deacetylation of Chitin Nanowhiskers on the Performance of PCL/PLA Bio-Nanocomposites.

The multiple roles of organic nanofillers in biodegradable nanocomposites (NC) with a blend-based matrix is not yet fully understood. This work highlights combination of reinforcing and structure-directing effects of chitin nanowhiskers (CNW) with different degrees of deacetylation (DA), i.e.

2-Methyl-6-(4-aminophenyl)-4,5-dihydro-3(2)-pyridazinone Synthon for Some New Annelated 1,2,3-Selena/Thiadiazoles and 2-Diazaphospholes with Anticipated Biological Activity and Quantum Chemical Calculations.

A convenient and efficient synthetic protocol for the new selenadiazole. Thiadiazole and diazaphosphole derivatives incorporating a pyridazine moiety originating from 4-(4-aminophenyl)-4-oxobutanoic acid () were described. All newly synthesized compounds were evaluated for their antimicrobial activity using the disk diffusion method, and their cytotoxicity was evaluated against brine shrimp lethality bioassay.

Effect of Polydopamine Coating of Cellulose Nanocrystals on Performance of PCL/PLA Bio-Nanocomposites.

In bio-nanocomposites with a poly(lactic acid) (PLA)/poly(ε-caprolactone) (PCL) matrix with neat and polydopamine (PDA)-coated cellulose nanocrystals (CNCd), the use of different mixing protocols with masterbatches prepared by solution casting led to marked variation of localization, as well as reinforcing and structure-directing effects, of cellulose nanocrystals (CNC). The most balanced mechanical properties were found with an 80/20 PLA/PCL ratio, and complex PCL/CNC structures were formed. In the nanocomposites with a bicontinuous structure (60/40 and 40/60 PLA/PCL ratios), pre-blending the CNC and CNCd/PLA caused a marked increase in the continuity of mechanically stronger PLA and an improvement in related parameters of the system.

Synthesis of Some Mono- and Disaccharide-Grafting Phthalazine Derivatives and Some New -Nucleoside Analogues: Antibacterial Properties, Quantum Chemical Calculations, and Cytotoxicity.

A highly efficient and versatile synthetic approach for the synthesis of 4-(pyren-1-ylmethyl)-1-(d-glycosyloxy) phthalazine nucleosides ,, , -nucleosides , , , and acyclo nucleosides ,, , and - was described and fully characterized. Furthermore, a series of desired new nucleoside analogues containing Se of 4-(pyren-1-ylmethyl) phthalazine-1(2)-selenone - were synthesized. The structures of all reported compounds were confirmed by IR, H-NMR, C-NMR, MS and elemental analysis.

Synergistic performance of collagen-g-chitosan-glucan fiber biohybrid scaffold with tunable properties.

Hybrid biocomposite scaffolds (HBS) that serve as a carrier for cell proliferation and differentiation are increasingly used for tissue regeneration. 3D hybrid scaffold based on collagen-grafted-chitosan-glucan fiber (CO-g-CGF-HBS) was prepared by freeze-drying technique. The swelling percentage, hydrolytic stability, and modulus of elasticity of HBS were enhanced after the chemical modification of CO with CGF.

Humoral Immune Memory to Hepatitis B Vaccine after Primary Vaccination of Children and Adolescents in Assiut, Egypt.

Objectives: We sought to assess the prevalence of hepatitis B virus (HBV) seroprotection among vaccinated children in the Assiut governorate, Egypt, and assess a booster dose immune memory response among non-seroprotected children.

Methods: Using a multistage cluster sample, 566 children were recruited from three clusters: one urban and two rural. Children were aged from nine months to 16 years old.

Chitosan-glucan complex hollow fibers reinforced collagen wound dressing embedded with aloe vera. II. Multifunctional properties to promote cutaneous wound healing.

This study presents an innovative multifunctional system in fabricating new functional wound dressing (FWD) products that could be used for skin regeneration, especially in cases of infected chronic wounds and ulcers. The innovation is based on the extraction, characterization, and application of collagen (CO)/chitosan-glucan complex hollow fibers (CSGC)/aloe vera (AV) as a novel FWS. For the first time, specific hollow fibers were extracted with controlled inner (500-900 nm)/outer (2-3 µm) diameters from mycelium of Schizophyllum commune.

Hyaluronan biofilms reinforced with partially deacetylated chitin nanowhiskers: Extraction, fabrication, in-vitro and antibacterial properties of advanced nanocomposites.

Fabrication of nanocomposite biofilms with enhanced mechanical and antibacterial properties was successfully achieved from hyaluronan (HA) and partially deacetylated chitin nanowhiskers (ChNWs) by a casting-evaporation method. The hydrolysis process of chitin showed an important role in the dimensions, stability, and the crystallinity of extracted ChNWs in a time-dependent manner. The volume fraction of ChNWs nanofiller varying from (0.

Comparative study of chitosan and silk fibroin staple microfibers on removal of chromium (VI): Fabrication, kinetics and thermodynamic studies.

Short staple microfibers (SSM) based on chitosan (CS) or silk fibroin (SF) were fabricated via the wet-rotate-spinning technique and employed to adsorb hexavalent chromium from aqueous solution. Adsorption efficiencies, physicochemical and morphological properties of CS and SF-SSM were systematically investigated and evaluated before and after adsorption of Cr(VI) using different techniques like ATR-FTIR, TGA, XRD, XPS, and SEM. CS and SF-SSM showed removal efficiency (>90 %) toward Cr(VI) ions.

Chitosan-glucan complex hollow fibers reinforced collagen wound dressing embedded with aloe vera. Part I: Preparation and characterization.

Collagen (CO)/chitosan-glucan complex (CSGC) hollow fibers encapsulated aloe vera (AV) dressing scaffold (CO/CSGC@AV) were fabricated for the first time by the freeze-dried process. Extraction process, morphology, mechanical properties, pore size, porosity, swelling ability, and degradation behavior of composites scaffold were investigated. CSGC hollow fibers were extracted from mycelium of Schizophyllum commune CSGC hollow fiber exhibited inner diameter of (600 ± 250 nm) and outer fiber diameter of (2.

Electrospinning of hyaluronan/polyvinyl alcohol in presence of in-situ silver nanoparticles: Preparation and characterization.

Novel nanofibers mats were fabricated by electrospinning of polyvinyl alcohol/hyaluronan (PVA/HA) solutions in the presence of silver nanoparticles (AgNPs). The AgNPs were synthesized by in-situ chemical reduction of silver ions (Ag) using HA as a reducing and stabilizing agent. Narrow size distribution and spherical shape of AgNPs were achieved by optimizing the initial silver nitrate concentration (0.

Relationship between Serum Level of Endocan and Severity of Childhood Asthma.

Endocan is an endothelial cell-associated proteoglycan that is preferentially expressed by renal and pulmonary endothe¬lium. It reflects endothelial activation and dysfunction, this study aimed to investigate the role of Endocan in bronchial asthma and correlate their levels with the severity of asthma. Sixty children with mild and moderate asthma and 20 healthy controls were included in the study and subjected to full clinical examination, Anthropometric measurements, pulmonary function test, CBC and assay of serum level of Endocan using ELISA.

A novel in situ silver/hyaluronan bio-nanocomposite fabrics for wound and chronic ulcer dressing: In vitro and in vivo evaluations.

In-situ formed hyaluronan/silver (HA/Ag) nanoparticles (NPs) were used to prepare composite fibers/fabrics for the first time. Different concentrations of silver nitrate (1, 2mg/100ml) were added at ambient temperature to sodium hyaluronate solution (40mg/ml), then the pH was increased to 8 by adding sodium hydroxide. The in-situ formed HA/Ag-NPs were used to prepare fibers/nonwoven fabrics by wet-dry-spinning technique (WDST).

Preparation and characterization of alginate/silver/nicotinamide nanocomposites for treating diabetic wounds.

Silver/Alginate/Nicotinamide nanoparticles composite (Ag/ALG/Nic) was prepared and used for the first time to fabricate wound dressing material. Sodium alginate (ALG) was used as reducing and stabilizing agents for preparation of silver nanoparticles (Ag-NPs). Effect of concentrations of alginate (ALG) on the particle size of silver were studied and confirmed by different techniques like UV/vis spectroscopy, transmission electron microscope (TEM) and dynamic light scattering (DLS).

Evaluation of aldosterone excretion in very low birth weight infants.

Data about aldosterone production and excretion in the neonatal period are still few and controversial. Our objectives are to assess urinary aldosterone excretion (UAE) in very low birth weight (VLBW) infants and to identify clinical and biochemical variables that may influence this excretion. Thirty VLBW infants (14 males and 16 females), their gestational age <32 weeks and body weight <1500 g, were included in the study.

Novel chitin/chitosan-glucan wound dressing: Isolation, characterization, antibacterial activity and wound healing properties.

Chitin/chitosan-glucan complex (ChCsGC) was isolated from Schizophyllum commune (S. commune) and dissolved for the first time in precooled (-15°C) 8wt.% urea/6wt.

Wound healing of different molecular weight of hyaluronan; in-vivo study.

Recruitment of cells and mediators is altered during impaired wound healing, thereby delaying this process. To overcome this problem, the correlation of wound healing in older rats, and the impact of different molecular weight of hyaluronan without silver nanoparticles; (low-HA1), (High-HA2), (Medium- HA3) and with silver nanoparticles (High-HA4) is investigated. The superior HA were selected to be further investigated onto diabetic wounds.

Accurate micro-computed tomography imaging of pore spaces in collagen-based scaffold.

In this work we have used X-ray micro-computed tomography (μCT) as a method to observe the morphology of 3D porous pure collagen and collagen-composite scaffolds useful in tissue engineering. Two aspects of visualizations were taken into consideration: improvement of the scan and investigation of its sensitivity to the scan parameters. Due to the low material density some parts of collagen scaffolds are invisible in a μCT scan.

Wound dressing based on chitosan/hyaluronan/nonwoven fabrics: Preparation, characterization and medical applications.

Thin layers of chitosan (positively charged)/sodium hyaluronate (negatively charged)/nonwoven fabrics were constructed by polyelectrolyte multilayer pad-dry-cure technique. Pure chitosan (CS) was isolated from shrimp shell and immobilized onto nonwoven fabrics (NWFs) using citric acid (CTA) as cross linker and solvent agents through a pad-dry-cure method. The prepared thin layer of chitosan citrate/nonwoven fabrics (CSCTA/NWFs) were consequently impregnated with hyaluronan (CSCTA/HA/NWFs) in the second path through a pad-dry-cure method.

Effectiveness of hepatitis B virus vaccination program in Egypt: Multicenter national project.

Aim: To assess the effectiveness of hepatitis B virus (HBV) vaccination program among fully vaccinated children.

Methods: A national community based cross-sectional study was carried out in 6 governorates representing Egypt. A total of 3600 children aged from 9 mo to 16 years who were fully vaccinated with HBV vaccine during infancy were recruited.

Chitin and chitosan from Brazilian Atlantic Coast: Isolation, characterization and antibacterial activity.

Chitin and chitosan were obtained by chemical treatments of shrimp shells. Different particle sizes (50-1000 μm) of the raw material were used to study their effect on size distribution, demineralization, deproteinization and deacetylation of chitin and chitosan isolation process. The particle size in the range of 800-1000 μm was selected to isolate chitin, which was achieved by measuring nitrogen, protein, ash, and yield %.