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Alkenyl succinic anhydride (ASA) is an oily paper sizing agent that is generally introduced into the paper manufacturing system as an ASA-in-water emulsion. In this paper, ASA-in-water emulsions are prepared by homogenizing the mixture of ASA and aqueous dispersion of Laponite modified with alanine. The modification of Laponite with alanine reduces the emulsion droplet size, and enhances the emulsion stability against coalescence due to lowering the interfacial tension between ASA and water containing Laponite and improving the affinity of Laponite particles toward ASA. Infrared spectrum analysis indicates that the adsorption of alanine on the Laponite particles retards the hydrolysis of ASA when the alanine-modified particles are employed to stabilize ASA emulsions. Meanwhile, the sizing efficiency of the as-prepared ASA emulsion is also improved by the modification of Laponite with alanine, and more dependent on emulsion droplet size than on the hydrolysis of ASA.

Cellulose-based photocatalytic paper was prepared with a papermaking technique, in which TiO 2 nanoparticle loaded carbon fibers were used together with cellulose fibers as raw materials. TiO 2 nanoparticles were loaded on carbon fibers with either Na 2 SiO 3 or Al 2 (SO 4 ) 3 as adhesive. They are distributed on carbon fibers in a form of small clusters. The photodegradation behaviors of the as-prepared papers were investigated using methyl orange (MO) solution as a target pollutant. It was found that the degradation effects of papers on MO using sodium silicate as the adhesive of TiO 2 nanoparticles are higher than those using aluminum sulfate as adhesive. When the ratio of carbon fiber to cellulose fiber is 1:1, the photocatalytic paper exhibits a high degradation performance. The introduction of poly(amideamine-epichlorohydrin) (PAE) as a paper wet strengthening agent had no significant influence on the photocatalytic activities of paper. In addition, the photocatalytic paper exhibits quite stable photocatalytic activity under UV-light irradiation and can be used repeatedly. The simple procedure is promising for the manufacture of paper with high photocatalytic activity.

As a paper sizing agent, alkenyl succinic anhydride (ASA) emulsion is generally stabilized by cationic starch or synthetic polymer. In this paper, Laponite and urea were employed as particle stabilizer and the modifier of Laponite particle, respectively, to stabilize the ASA emulsion. It is founded that the presence of urea enhances the stability of ASA emulsion, reduces the emulsion droplet size, resulting in improved sizing performance of the ASA emulsion. ASA emulsion with smallest droplet size and best sizing performance on BCTMP is obtained at the urea dosage of 50 wt% based on Laponite. The sizing test of ASA emulsion and the infrared spectrum analysis of ASA substances separated from ASA emulsions with different storage time indicate that the introduction of urea in emulsification process can restrain the hydrolytic action of ASA effectively and sustain the sizing performance of ASA emulsion even two hours after its preparation. This is a possible way to solve the problem that paper mills have always encountered: the too rapid hydrolysis of ASA emulsion.

ASA emulsions costabilized by Laponite and polyaluminum sulfate (PAS) were prepared by homogenizing the mixture of ASA and aqueous dispersion of Laponite and PAS. The properties, sizing performance and hydrolysis resistance of the prepared ASA emulsions, were investigated in this article. The results show that the introduction of PAS significantly improves the stability, hydrolysis resistance, and sizing performance of ASA emulsions. The ASA emulsion stabilized by 0.5% of Laponite (based on total mass of emulsion) and 2% of PAS (based on the mass of Laponite) shows high hydrolysis stability and high sizing efficiency on bleached chemi-thermomechanical pulp. At the addition level of 0.3% based on bleached chemi-thermomechanical pulp, the sizing degree of ASA-sized paper can be as high as 120 s. Even when the storage time of the ASA emulsion exceeds 3 h, its sizing performance is hardly changed. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

The effect of testosterone on the precursor mitochondrial aspartate aminotransferase (pmAAT) gene and on pmAAT-mRNA was studied in rat ventral prostate (VP) and pig prostate epithelial cells. Castration significantly decreased the level of nuclear pmAAT transcripts in VP; whereas testosterone treatment of castrated animals restored the level of pmAAT transcripts. Correspondingly, castration resulted in a marked decrease in the transcription rate of the pmAAT gene; whereas testosterone treatment markedly increased the transcription rate. In vitro studies with isolated pig prostate epithelial cells demonstrated that testosterone directly and rapidly induced a transient increase in the transcription rate of the pmAAT gene. The increase in transcription was associated with an increase in the steady-state level of pmAAT-mRNA. Similar in vitro effects were observed with isolated VP epithelial cells. In addition to its stimulatory effect on transcription of the pmAAT gene, testosterone also increased the half-life of pmAAT-mRNA from 2 h in the absence of hormone to 16 h in its presence. Consequently, testosterone appears to stabilize the pmAAT-mRNA. The combination of its immediate effect on stimulating the transcription of the pmAAT gene and its stabilizing effect on pmAAT-mRNA would account for the increase in the steady-state level of pmAAT-mRNA by testosterone. These studies support our proposal that, through these effects, testosterone increases the biosynthesis of mAAT thereby increasing the transamination of aspartate to oxaloacetate and ultimately increasing the synthesis of citrate. This appears to provide at least one of the mechanisms by which testosterone regulates prostate citrate production.