Synthesis, characterization, DFT studies, and adsorption properties of sulfonated starch synthesized in deep eutectic solvent.

In this study, sulfonated starch (SS) was successfully synthesized using sulfamic acid as a sulfonating agent in a deep eutectic solvent (DES). Four-factor and three-level orthogonal experiments were conducted to determine the optimal preparation conditions, which were found to be a molar ratio of starch to urea of 1:20, a reaction temperature of 90 °C, a reaction time of 5 h, and a stirring speed of 200 rpm. The sulfonation reaction mechanism was extensively studied using various techniques, including Fourier transform infrared spectroscopy, elemental analysis, X-ray diffraction, molecular weight, particle distribution, X-ray photoelectron spectroscopy, scanning electron microscopy, and DFT calculations. The results showed that the sulfonation reaction slightly damaged starch granules, occurred on the surface of starch granules, and on the O6 atoms of the glucose unit. SS exhibited a wide pH range of application (5-10), a fast adsorption rate (400 s to reach adsorption equilibrium), and a high adsorption capacity (118.3 mg/g) under optimal conditions. The adsorption process of SS for methylene blue followed the pseudo-first-order kinetic model and was consistent with the Langmuir model, which was endothermic and spontaneous. The adsorption process was attributed to hydrogen bonding and electrostatic interactions.

Effects of Individualized Nursing Based on Zero-Defect Theory on Perioperative Patients Undergoing Laparoscopic Cholecystectomy.

Objective: This study is aimed at analyzing the effects of individualized nursing based on the zero-defect theory on perioperative patients undergoing laparoscopic cholecystectomy. Methods: 174 patients who underwent laparoscopic cholecystectomy from 1st November 2019 to 30th November 2020 were enrolled as the research subjects and randomly divided into control and observation groups. The patients in the control group received conventional perioperative nursing care, and the patients in the observation group were treated with individualized nursing based on the zero-defect theory. Results: The heart rate, diastolic blood pressure, and systolic blood pressure level of patients in two groups after nursing decreased significantly, and the reduction in the observation group was more significant than that in the control group. The depression and anxiety scores of the two groups after nursing were decreased, and the decrease in the observation group was significantly greater than that in the control group. The time to first postoperative exhaust, return to normal intake, out-of-bed activity, and hospital stay in the observation group was less than that in the control group. The incidence of postoperative complications in the observation group was substantially lower than that in the control group. The satisfaction degree of nursing care in the observation group was significantly higher than that in the control group. Conclusion: Individualized nursing care based on zero-defect theory can effectively reduce the perioperative psychological stress response of patients with laparoscopic cholecystectomy. It helps to improve the negative emotions of depression and anxiety, promotes the recovery of disease, reduces postoperative complications, and improves nursing satisfaction, which is worthy of clinical promotion.

Adsorption of copper (II) and cadmium (II) ions by in situ doped nano-calcium carbonate high-intensity chitin hydrogels.

Most natural polymers exhibit limited functional groups, which is not favourable for the adsorption of various ions and their utilisation. To overcome this drawback, a novel in-situ-doped nano-calcium carbonate (CaCO3) chitin hydrogel was synthesised as an efficient adsorbent for Cu (II) and Cd (II) ions. Scanning electron microscopy and Brunauer-Emmett-Teller results revealed that the synthesised CaCO3/chitin hydrogel exhibited loose macropores and mesopores. Subsequently, Fourier transform infrared, Raman, and X-ray diffraction characterisation characterisation proved that chitin was successfully doped with nano-CaCO3. The mechanical properties of CaCO3/chitin hydrogel were superior to those of the unmodified chitin hydrogel and could efficiently adsorb Cu (II) and Cd (II) ions in water. The effect of pH, initial concentration, adsorbent dosage, and temperature was assessed to determine the adsorption properties of the hydrogel. Under suitable experimental conditions, the maximum adsorption rate of the CaCO3/chitin hydrogel was approximately 96%. The time-dependent adsorption kinetics followed a quasi-second order model, and the adsorption process followed the Langmuir model. The maximum adsorption capacities of Cu (II) and Cd (II) according to the Langmuir curve were 194.61 and 191.58 mg/g, respectively. Compared with the binary competitive system, the material exhibited a specific selectivity to the adsorption of Cu (II). X-ray photoelectron spectroscopy (XPS) revealed that nitrogen and oxygen atoms were involved in chelation with the metal ions. The successful compounding of calcium carbonate nanoparticles provided more active adsorption sites for the gel. The novel material exhibited excellent adsorption effects on Cu (II) and Cd (II) ions when applied to a water sample. Thus, the novel material exhibits excellent potential for application. The Cu (II) and Cd (II)ion removal efficiencies after five successive adsorption cycles were higher than 90%, which indicated that the composite material exhibited excellent stability and reproducibility.

Preparation and application of a polymer with pH/temperature-responsive targeting.

Targeted drug carrier systems not only prolong the long-term circulation of drugs, but also improve their bioavailability. To obtain a pH/temperature synergistically responsive polymer carrier, temperature and pH-sensitive groups were chemically grafted onto a cassava starch backbone. Secondly, the structure of the polymer micelle carrier was characterized, and finally the drug loading performance and capacity of the drug carrier were explored. It was observed that cumulative drug release was low when the temperature and pH values met one of two conditions. Only at a high temperature and low pH (T = 38 °C, pH = 5.5, as in tumor tissue) did cumulative drug release reach its maximum value. The design of the polymer carrier described in the present study represents a novel paradigm in precision release drug carriers.

Preparation, characterization, and performance analysis of starch-based nanomicelles.

A novel amphiphilic starch-based polymer carrier (R-St-PEG; R = hexadecyl, St = starch, PEG = polyethylene glycol) was prepared using tapioca starch. It was then applied as an effective carrier for encapsulated drug, and used for sustained drug release. First, tapioca starch was made to react with hexadecane bromide (R16) for hydrophobic modification, and then the hydrophobically-modified tapioca starch molecules were grafted onto hydrophilic carboxyl-terminated PEG (mPEG-COOH). The drug-loading capacity and drug release behavior of R-St-PEG were systematically evaluated using curcumin as drug. The results show that the polymer has good drug-loading capacity and sustained-release properties, and it can act as an effective drug carrier. Thus, this study provides a suitable platform for preparing stable amphiphilic polymer carriers and broadens the application range of tapioca starch.

Physical Modification of Cellulose Nanocrystals with a Synthesized Triblock Copolymer and Rheological Thickening in Silicone Oil/Grease.

This study investigates the rheological thickening effect of surface-modified cellulose nanocrystals (mCNCs) with a triblock copolymer on silicone oil. An amphipathic copolymer comprising hydrophilic methoxypolyethylene glycols and hydrophobic polydimethylsiloxane segments is synthesized and introduced in silicone oil by physical adsorption of rodlike cellulose nanocrystals (CNCs). The surface-modified copolymer acts as a "bridge" to enhance the compatibility between CNCs and base oil, which produces the hybrid oils/greases containing homogeneously dispersed mCNCs at varied loading levels of 5-20 wt %. The presence of this rigid additive remarkably increases the viscosity of silicone oil, accompanied with the transition from flowable to nonflowable behavior with a gradual increase of mCNC loading levels. Furthermore, the change of storage and loss modulus of the fabricated hybrid oils/greases indicates the formation of a three-dimensional network by the chain entanglement and interactions between the copolymer and silicone oil (at a critical loading level of 15 wt % mCNC), which promotes the rigid CNCs to act as the physical cross-linking point for the significant transition from liquid to quasi-solid state.

Michael acceptor in gambogic acid--Its role and application for potent antitumor agents.

Gambogic acid (GA), a natural product with unique structure, was reported to have broad antiproliferation activities against cancer cell lines. As a reactive Michael acceptor, the 10-position of GA is susceptible to nucleophiles, thus limiting its clinical application as an anticancer agent. Moreover, the 6-OH forms an intramolecular hydrogen bond with 8-CO, which can make the 9, 10 double bond more reactive to nucleophiles. In this essay, two strategies (A and B) were applied to solve the above-mentioned problems. Strategy A was to increase the steric hindrance of C-10 to reduce the activity of GA towards nucleophiles. Strategy B was to replace the hydroxyl of C-6 with other substituents based on the assumption that the intra-molecular hydrogen bond could increase the electrophilicity of C-10. Results showed the electrophilicity of C-10 disappeared as well as the antiproliferation activity against cancer cell lines by introducing a methyl group at C-10. Strategy B showed that the electrophilicity of C-10 was reduced dramatically while maintained the activity by replacement of the hydroxyl of C-6 with neutral or basic groups.