This study aims to optimize the process for preparing chitosan-based ultrasound-coupled hydrogel pads and investigate their application potential in ultrasonography. Chitosan, 2-acrylamido-2-methylpropanesulfonic acid, and N-isopropylacrylamide were used as the main materials to prepare chitosan-based ultrasound-coupled hydrogel pads. The free-radical polymerization conditions were optimized by a three-factor, three-level orthogonal test with the tensile strength and ultrasound image quality of the hydrogel pads as evaluation indicators. The optimal prescription was selected by optimizing three factors of raw material ratio, polymerization temperature, and freeze-drying time. The structure and performance of the hydrogel pads were characterized by a scanning electron microscope, a universal testing machine, and an ultrasonic diagnostic instrument. The results showed that the optimal prescription was as follows: the chitosan: 2-acrylamide-2-methylpropanesulfonic acid: N-isopropylacrylamide ratio of 2:0.55:17.27, the polymerization temperature of 25 ℃, and the freeze-drying time of 48 h. The ultrasonically-coupled hydrogel pads prepared under these conditions were transparent, with a porous structure, good adhesion, and high tensile strength. The hydrogel pads had good swelling properties and the swelling degree decreased slowly on day 10. The quality of the ultrasound images obtained via chitosan-based hydrogel pads was not significantly different from that obtained via medical ultrasound coupling agent. In this study, we analyzed the effects of different preparation processes on the gel formation of chitosan-based ultrasound-coupled hydrogel pads. The hydrogel pads were transparent and mild and non-irritating to the human body, serving as an ultrasound transmission material for ultrasonography.
Chitosan/chemistry* ; Hydrogels/chemistry* ; Acrylamides/chemistry* ; Ultrasonography ; Polymerization ; Sulfonic Acids/chemistry* ; Alkanesulfonates/chemistry* ; Tensile Strength ; Freeze Drying ; Temperature

This review briefly describes the origin, chemistry, molecular mechanism of action, pharmacology, toxicology, and ecotoxicology of palytoxin and its analogues. Palytoxin and its analogues are produced by marine dinoflagellates. Palytoxin is also produced by Zoanthids (i.e. Palythoa), and Cyanobacteria (Trichodesmium). Palytoxin is a very large, non-proteinaceous molecule with a complex chemical structure having both lipophilic and hydrophilic moieties. Palytoxin is one of the most potent marine toxins with an LD50 of 150 ng/kg body weight in mice exposed intravenously. Pharmacological and electrophysiological studies have demonstrated that palytoxin acts as a hemolysin and alters the function of excitable cells through multiple mechanisms of action. Palytoxin selectively binds to Na(+)/K(+)-ATPase with a Kd of 20 pM and transforms the pump into a channel permeable to monovalent cations with a single-channel conductance of 10 pS. This mechanism of action could have multiple effects on cells. Evaluation of palytoxin toxicity using various animal models revealed that palytoxin is an extremely potent neurotoxin following an intravenous, intraperitoneal, intramuscular, subcutaneous or intratracheal route of exposure. Palytoxin also causes non-lethal, yet serious toxic effects following dermal or ocular exposure. Most incidents of palytoxin poisoning have manifested after oral intake of contaminated seafood. Poisonings in humans have also been noted after inhalation, cutaneous/systemic exposures with direct contact of aerosolized seawater during Ostreopsis blooms and/or through maintaining aquaria containing Cnidarian zoanthids. Palytoxin has a strong potential for toxicity in humans and animals, and currently this toxin is of great concern worldwide.
Acrylamides ; chemistry ; isolation & purification ; toxicity ; Animals ; Anthozoa ; pathogenicity ; physiology ; Dinoflagellida ; pathogenicity ; physiology ; Dogs ; Guinea Pigs ; Haplorhini ; Humans ; Lethal Dose 50 ; Marine Toxins ; chemistry ; isolation & purification ; toxicity ; Mice ; Rabbits ; Rats ; Seaweed ; pathogenicity ; physiology ; Shellfish Poisoning ; physiopathology ; Sodium-Potassium-Exchanging ATPase ; metabolism

Poly-N-isopropylacrylamide (PNIPAAm) is a new kind of intelligent material. It shows favorable thermo sensitivity because of the structure of hydrophilic acrylamino and hydrophobic isopropyl. PNIPAAm also shows good biocompatibility and non-toxicity. All the characters as above make it an ideal extra cellular matrix material for tissue engineering. This paper reviews its application in tissue engineering.
Acrylamides ; chemistry ; Acrylic Resins ; Animals ; Biocompatible Materials ; Hot Temperature ; Humans ; Polymers ; chemistry ; Tissue Engineering ; Tissue Scaffolds

To study the chemical constituents of the Entada phaseoloides (L.) Merr., seeds of Entada phaseoloides were extracted with 70% ethanol at room temperature. Isolation and purification were performed by silica gel, reversed-phase silica gel column chromatography and semi-preparative HPLC. Structures of the pure compounds were established on the basis of spectral analysis. Four sulfur-containing amide compounds were isolated from the n-BuOH-soluble fraction and identified as entadamide A-beta-D-glucopyranosyl-(1-->3)-beta-D-glucopyranoside (1), entadamide A (2), entadamide A-beta-D-glucopyranoside (3) and clinacoside C (4). Compound 1 is a new compound. Compound 4 is isolated from the genus Entada for the first time.
Acrylamides ; chemistry ; isolation & purification ; Fabaceae ; chemistry ; Molecular Structure ; Plants, Medicinal ; chemistry ; Seeds ; chemistry ; Thioglucosides ; chemistry ; isolation & purification

AIMTo establish 3D QSAR model of propenamides with anti-malarial activities.

METHODSChemical synthesis combined with comparative molecular field analysis (CoMFA).

RESULTSGenerated QSAR models for activities of inhibiting chloroquine resistive malaria (W2) and chloroquine sensitive malaria (D6).

CONCLUSIONThe activity of anti-W2 depends mostly on steric interaction and the activity of anti-D6 depends on both steric and electrostatic interaction.

Acrylamides ; chemical synthesis ; chemistry ; pharmacology ; Animals ; Antimalarials ; chemical synthesis ; chemistry ; pharmacology ; Chloroquine ; pharmacology ; Drug Resistance ; Molecular Conformation ; Molecular Structure ; Plasmodium ; drug effects ; Quantitative Structure-Activity Relationship