A study of the properties of hydrophobically associating water-soluble polymers used in drilling fluids

Hydrophobically associating water-soluble polymers (HPAP) have been synthesized from acrylamide(AM), acrylate (AA), 2-acrylamido-2-methyl propane sulfonic acid (AMPS) and hydrophobic monomer (AP) in aqueous solution by radical polymerization. New polymer drilling fluids are made up of HPAP, which is used as viscosifiers and encapsulation agents. Properties of this system are reported in this paper. Results indicate that this system has a high value of yield point to plastic viscosity (YP/PV≥0.7), high viscosity at a low-shear rate (LSRV≥30000mPa·s), excellent shear thinning behavior, good solid-carrying behavior, resistance to shear, good thermal stability (as high as 140℃) and salt resistance. The system has excellent behavior in high-density solution of NaCl and in calcium and magnesium rich saline solutions. Hence, HPAP also can be used in saltwater polymer drilling fluids.

Structure, properties and application to water-soluble coatings of complex antimicrobial agent Ag-carboxymethyl chitosan-thiabendazole

The structure, properties and application to water-soluble coatings of a new complex antimicrobial agent Ag-carboxylmethyl citosan-thiabendazole （Ag-CMCTS-TBZ） prepared from different materiel ratios were reported. The silver ions were preferably coordinated with the free-NH2 groups and the -OH groups of secondary alcohol and carboxyl in CMCTS. TBZ preferably bonded to carboxyl group in CMCTS by electrostatic force and hydrogen bonding. Increase in silver ions content in the complex agent improved to some limited extent the antibacterial activity, but enhanced coloring and cost of the complex agent. Increase in TBZ content resulted in increase of antifungal activity, but decrease of water solubility of the complex agent. The antimicrobial MICs of the complex agent to Esherichia coil, Staphylococcus aureus, Candida albicans, Aspergillus niger, Mucor sp. were 20 -80, 15 -60, 20 - 55, 40 - 250, and 400 - 1700 mg/kg, respectively. Addition of 0.1% of this complex agent to acrylic emulsion paint made the paint without substantial change in color, luster, viscosity, odor or pH value, but with an excellent and chronically persisting broad-spectra antimicrobial activity.

Electrostatic spraying for fine-tuning particle dimensions to enhance oral bioavailability of poorly water-soluble drugs

While spray-drying has been widely utilized to improve the bioavailability of poorly water-soluble drugs,the outcomes often exhibit suboptimal particle size distribution and large particle sizes,limiting their effectiveness.In this study,we introduce electrostatic spraying as an advanced technology tailored for poorly water-soluble drugs,enabling the fabrication of nanoparticles with fine and uniform particle size distribution.Regorafenib(1 g),as a model drug,copovidone(5 g),and sodium dodecyl sulfate(0.1 g)were dissolved in 200 ml ethanol and subjected to conventional-spray-dryer and electrostatic spray dryer.The electrostatic spray-dried nanoparticles(ESDN)showed smaller particle sizes with better uniformity compared to conventional spray-dried nanoparticles(CSDN).ESDN demonstrated significantly enhanced solubility and rapid release in water.In vitro studies revealed that ESDN induced apoptosis in HCT-116 cells to a greater extent,exhibiting superior cytotoxicity compared to CSDN.Furthermore,ESDN substantially improved oral bioavailability and antitumor efficacy compared to CSDN.These findings suggest that ESD shows potential in developing enhanced drug delivery systems for poorly water-soluble drugs,effectively addressing the limitations associated with CSD methods.

Inhalation properties of water-soluble drug loaded liposomes atomized by nebulizer

The pulmonary route presents several advantages in designing drug delivery systems in both systemic and topical administration.The use of particulate carriers is an attractive method for designing pulmonary drug delivery systems,because such carriers could control drug release and selective drug targeting when the carriers reach the target site in the lung.The prevention of local irritation,reduced drug toxicity,and improved drug stability are also preferable results of utilizing such carrier systems.Among a number of particulate carriers,liposomes have an advantage in safety,because they consist of phospholipids,which are bio-components.

Aggregation-dependence of Optical Properties and Fluorescence Quenching of a Water-soluble Poly(phenylene ethynylene)

The solvent and surfactant-dependent aggregation behaviors of the anionic poly（phenylene ethynylene） were studied and used to tune optical properties and fluorescence quenching efficiency.

Effects of Water-Soluble Co-Solvent on Properties of W/O Pickering Emulsions

Effects of water-soluble co-solvents （WSCs）on the properties of water/oil Picketing emulsions were investigated. Picketing emulsions were prepared in the system of 1,2,4-trimethylbenzene （TMB）/hydrophobic sil- ica/water with varied concentrations of WSCs （ethanol, acetic acid and glycerin）. Mean droplet diameter distribu- tions of the obtained emulsions were studied to investigate the effects of WSCs types and concentrations. The results demonstrated that mean droplet diameter distributions decreased at first and then increased with the increase of WSC concentration. Moreover, the effect of WSC concentration on the phase inversion locus was further investi- gated. At the same time, infrared radiation （IR）spectrometer was used to investigate the mechanism. The results showed that the WSC attaching on hydrophobic silica changed the wettability of the particles, which facilitated the formation and phase inversion of the emulsion. The hydrogen bonds between the co-solvent groups attaching on the solid particles made a great effect on the droplet size of the emulsion and strengthened the interaction among emulsifiers. Overall, proper WSC was in favor of the stability of Picketing emulsion.

Molecular simulation study of the microstructures and properties of pyridinium ionic liquid[HPy][BF_(4)]mixed with acetonitrile

The microstructures and thermodynamic properties of mixed systems comprising pyridinium ionic liquid[HPy][BF_(4)]and acetonitrile at different mole fractions were studied using molecular dynamics simulation in this work.The following properties were determined:density,self-diffusion coefficient,excess molar volume,and radial distribution function.The results show that with an increase in the mole fraction of[HPy][BF_(4)],the self-diffusion coefficient decreases.Additionally,the excess molar volume initially decreases,reaches a minimum,and then increases.The rules of radial distribution functions(RDFs)of characteristic atoms are different.With increasing the mole fraction of[HPy][BF_(4)],the first peak of the RDFs of HA1-F decreases,while that of CT6-CT6 rises at first and then decreases.This indicates that the solvent molecules affect the polar and non-polar regions of[HPy][BF_(4)]differently.

Research on the Construction of Intellectual Property System and Optimization of Business Environment in China

With the rapid development of globalization and information technology,intellectual property has been one of the key drivers of economic growth,and the construction of intellectual property system has become an important criterion for measuring the quality of business environment.This article is intended to explore the current status of intellectual property system construction in China,the challenges,and its relationship with the business environment,to propose the corresponding countermeasures and suggestions.The study finds that the legal system of intellectual property in China is gradually improving,and judicial and administrative protection are continuously strengthened.However,the challenges still remain such as frequent infringements,rights hard to protect and insufficient international cooperation.These issues not only affect the legitimate rights and interests of innovation entities,but also for the market fairness and the level of the business environment.Therefore,this article proposes that strengthening the perfection of the intellectual property legal system,enhancing intellectual property services and support capabilities,strengthening international cooperation and exchanges,and accelerating the cultivation of composite talents.It aims to provide theoretical references for the construction of intellectual property system and the optimization of the business environment,promote the high-quality development of economy and enhance the global competitiveness of the country.

Luminescent properties dependence of water-soluble CdTe quantum dots on stabilizing agents and reaction time

The influence of stabilizing agents and reaction time on the luminescent properties of water-soluble CdTe quantum dots(QDs) was discussed.The thioglycolic acid(TGA)-CdTe ODs were characterized by TEM,XRD and FTIR.It is found that larger-size QDs can be synthesized more easily when L-cysteine(Cys) or golutathione(GSH) is chosen as stabilizing agent and TGA is proper to prepare highly luminescent QDs because of the effect between Cd2+ and sulfhydryl group.Furthermore,the absorption wavelength,full width at half maximum(FWHM),stokes shift,photoluminescence(PL) quantum yield and PL stability of TGA-CdTe are strongly dependent on reaction time,in which the absorption wavelength changes against reaction time with an exponential function.The TGA-CdTe QDs prepared at 2 h possess more excellent luminescent properties.

Release Model of Water-soluble Chitosan Nanoparticles for Protein Delivery

[Objective] The experiment aimed to explore release rule of water-soluble chitosan (WSC) in vitro. [Method]The bovine serum albumin(BSA) was taken as a model protein drug and some existing release models such as Kinetics model, Gompertz model, Weibull model, Higuchi model and Logistic model were used to fit the BSA release profile from WSC carriers. [Result] Except Higuchi model and Logistic model, other models could fit BSA release profile better. [Conclusion] Gompertz two-order kinetics model could fit the release of WSC nano-particles better and model parameters had practical physical meaning.

Effect of Different Environmental Conditions on Algicidal Effect of Water-soluble Extracts of Chinese Chive

[Objective] The paper was to study the algicidal effect of water-soluble extracts of Chinese chive under different environmental conditions, so as to provide reference for further study and development of new algicidal substances. [Method] The effects of water-soluble extracts of Chinese chive on the growth of Microcystis aeruginosa under different pH, light and aeration conditions were compared and studied. [Result] The growth inhibition rate of water-soluble extracts of Chinese chive on M. aeruginosa was greater than 90% under different pH conditions. With the growth of M. aeruginosa, the culture liquid with different initial pH was finally tended to 9-9.5. The growth inhibition rate of water-soluble extracts of Chinese chive on algae cell increased with the prolongation of culture time within the light intensity range of 1 000-4 000 lx. The inhibition effect of water-soluble extracts of Chinese chive on M. aeruginosa under low light intensity（1 000 lx）was better than that under high light intensity, the best light intensity for growth was not conducive to the exertion of allelopathic effect. Meanwhile, aeration condition was more conducive to the inhibition effect of water-soluble extracts of Chinese chive on the growth of M. aeruginosa. [Conclusion] pH, light and aeration conditions all affected the inhibition effect of water-soluble extracts of Chinese chive treated by high temperature on M. aeruginosa. Understanding the effect of these environmental factors on algicidal effect of allelochemicals could provide reference for further study and development of new algicidal substances.

Effect of thatch on water-soluble phosphorus of pasture soil fertilized with broiler litter

The presence of a thatch layer in established pastures could reduce the contact between broiler litter and soil, thus increasing the potential for surface runoff contamination with litter P. We conducted a laboratory study to evaluate the effect of a thatch layer on the dynamics of water-soluble P in undisturbed cores taken from a pasture. Cores with and without a thatch layer received a surface application of broiler litter (5 thm-2) and were incubated at 25 oC for 56 d. The result showed that on the soil surface the contents of water soluble-P (39 kghm-2) of the cores with the thatch layer was higher than that (20 kghm-2) of the cores without the thatch layer. Therefore on well-established pastures fertilized with broiler litter, the presence of a thatch layer might lead to high concentrations of water-soluble P on the soil surface.

Nanocrystals for enhancement of oral bioavailability of poorly water-soluble drugs

Nanocrystals,a carrier-free colloidal delivery system in nano-sized range,is an interesting approach for poorly soluble drugs.Nanocrystals provide special features including enhancement of saturation solubility,dissolution velocity and adhesiveness to surface/cell membranes.Several strategies are applied for nanocrystals production including precipitation,milling,high pressure homogenization and combination methods such as Nano-Edge^(TM),SmartCrystal and Precipitation-lyophilization-homogenization(PLH)technology.For oral administration,many publications reported useful advantages of nanocrystals to improve in vivo performances i.e.pharmacokinetics,pharmacodynamics,safety and targeted delivery which were discussed in this review.Additionally,transformation of nanocrystals to final formulations and future trends of nanocrystals were also described.

Application of ion chromatography to the determination of water-soluble inorganic and organic ions in atmospheric aerosols

A simple, sensitive and convenient ion chromatography(IC) method was established for the simultaneous determination of twelve water-soluble inorganic anions(F -, Cl -, NO - 2, NO - 3, SO 2- 3, SO 2- 4, PO 3- 4), and fifteen water-soluble organic ions(formate, acetate, MSA, oxalate, malonate, succinate, phthalates, etc.) in atmospheric aerosols. The linear concentrations ranged from 0.005 μg/m 3 to 500 μg/m 3(r = 0.999—0.9999). The relative standard deviation(RSD) were 0.43%—2.00% and the detection limits were from 2.7 ng/m 3 to 88 ng/m 3. The proposed method was successfully applied to the simultaneous determination of those inorganic ions and organic ions in PM 2.5 of Beijing.

On-line Measurement of Water-Soluble Ions in Ambient Particles

Combining the system of rapid collection of ambient particles and ion chromatography, the system of rapid collection of fine particles and ion chromatography （RCFP-IC） was established to automatically analyze on-line the concentrations of water-soluble ions in ambient particles. Here, the general scheme of RCFP-IC is described and its basic performance is tested. The detection limit of RCFP-IC for SO4^2-, NO3^-, NO2^-, Cl^- and F- is below 0.3μg m^-3. The collection efficiency of RCFP-IC increases rapidly with increasing sized particles. For particles larger than 300 nm, the collection efficiency approaches 100%. The precision of RCFP-IC is more than 90% over 28 repetitions. The response of RCFP-IC is very sensitive and no obvious cross-pollution is found during measurement. A comparison of RCFP-IC with an integrated filter measurement indicates that the measurement of RCFP-IC is comparable in both laboratory experiments and field observations. The results of the field experiment prove that RCFP-IC is an effective on-line monitoring system and is helpful in source apportionment and pollution episode monitoring.

Adverse effects of metal exposure on chemotaxis towards water-soluble attractants regulated mainly by ASE sensory neuron in nematode Caenorhabditis elegans

Chemotaxis to water-soluble attractants is mainly controlled by ASE sensory neuron whose specification is regulated by che-1 in Caenorhabditis elegans. Our data suggested that exposure to high concentrations of metals, such as Pb, Cu, Ag, and Cr, would result in severe defects of chemotaxis to water-soluble attractants of NaCl, cAMP, and biotin. Moreover, the morphology of ASE neuron structures as observed by relative fluorescent intensities and relative size of fluorescent puncta of cell bodies, relative lengths of sensory endings in ASE neurons, and the expression patterns of che-1 were obviously altered in metal exposed animals when they meanwhile exhibited obvious chemotaxis defects to water-soluble attractants. In addition, the dendrite morphology could be noticeably changed in animals exposed to 150 μmol/L of Pb, Cu, and Ag. Furthermore, we observed significant decreases of chemotaxis to water-soluble attractants in Pb exposed che-1 mutant at concentrations more than 2.5 μmol/L, and in Cu, Ag, and Cr exposed che-1 mutant at concentrations more than 50 μmol/L. Therefore, impairment of the ASE neuron structures and functions may largely contribute to the appearance of chemotaxis defects to water-soluble attractants in metal exposed nematodes.

Preparation of Ultrafine Water-soluble Polymers Nanofiber Mats via Electrospinning

A series of water-soluble polymers such as poly（ethylene oxide）（PEO）, polyacrylamide（PAM） and poly（vinyl pyrrilidone）（PVP） was successfully prepared via the electrospinning of their aqueous solutions without the use of a surfactant. The effects of solution properties on the electrospinning of PEO, PAM and PVP solutions were investigated. The viscosity of the solution, charge density carried by the jet, and the surface tension of the solution are the key factors that influence the morphology and diameter size of the fibers. The viscosity of the solution was measured on a modular compact rheometer. The morphology and the diameter size distribution of the fibers were observed under an environmental scanning electron microscope（ESEM）. The results show that the diameters of the nanofibers electro spun from the solutions of these water soluble polymers were uniform and less than 300 nm.

Effect of kaolin on tensile strength and humidity resistance of a water-soluble potassium carbonate sand core

Water soluble cores(WSCs) have been widely applied in manufacture of complex metal components with hollow configurations or internal channels. However, the WSCs without any additons have low tensile strength and low humidity resistance. The purpose of this study is to prepare a water-soluble potassium carbonate sand core with addition of kaolin by the hot-temping method. The effects of kaolin on tensile strength, humidity resistance, fracture mechanism, as well as the gas evolution and collapsibility of WSCs were investigated. Results show that both the crystal morphology and the fracture mechanism of the inorganic salt are changed under the participation of kaolin, contributing to the increase of the tensile strength and the humidity resistance of the core. With the addition of 3wt.% kaolin, the tensile strength could be increased by a factor of 2, reached 1.50 MPa and the hygroscopic rate could be decreased by 14%, achieved 0.559%(after stored for 8 h), respectively. As the addition amount of kaolin increases from 0wt.% to 3wt.%, the main fracture mechanism changes from a adhesive to a cohesive fracture mechanism. The water-soluble potassium carbonate core obtained has the low gas evolution and excellent collapsibility, which makes it suitable for casting low melting metal with complex cavities and crooked channels.

Study on Dyeing Performance of Cationic Water-soluble Sulphur Black on Silk

A novel polyquaternaryammonium cationic sulphur black dye was synthesized and its dyeing behavior on silk was studied. The dye exhibited excellent dyeing fixation of up to 98.2 %, as well as excellent dyeing fastness on silk.

Phosphoryl choline-grafted water-soluble carbon nanotube

Water-soluble property is the precondition of biomedical evaluation and application of carbon nanotube （CNT）. Novel water- soluble CNT was synthesized in this letter by grafting phosphoryl choline （PC） onto multi-wall CNTs. Utilizing FTIR, XPS, TGA and TEM, the title CNTs were characterized and it was found that the target products could facilely dissolve in water. 2007 Tao Zhang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.