Chitosan-polyvinyl alcohol-diatomite hydrogel removes methylene blue from water.

Dye pollution in the aquatic environment can harm ecosystems and human health. Here, we developed a new green adsorbent by applying an improved drying process. Diatomite was embedded in a network structure formed between chitosan and polyvinyl alcohol without using any crosslinking agent to prepare chitosan-polyvinyl alcohol-diatomite hydrogel beads through alkali solidification. The beads were tested for removing a cationic dye (methylene blue (MB)) from water. The structure of the adsorbent beads was analysed using scanning electron microscopy, energy-dispersive spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy. The adsorption capacity was investigated, and the results indicated excellent MB adsorption properties. The adsorbents had a rough surface and high swelling capacity of 66.9 g/g. The maximum MB adsorption capacity was 414.70 mg/g, and the adsorption followed the Freundlich isothermal and quasi-second-order kinetic models. The adsorption was an endothermic spontaneous process governed by both intra-particle and external diffusion processes. The proposed adsorption mechanisms involved hydrogen bonding and electrostatic interactions. These adsorbent beads have considerable application potentials owing to their high adsorption capacity, green composition, and non-polluting nature.

Constructing a Hierarchical Hydrophilic Crosslink Network on the Surface of a Polyvinylidene Fluoride Membrane for Efficient Oil/Water Emulsion Separation.

Oil/water mixtures from industrial and domestic wastewater adversely affect the environment and human beings. In this context, the development of a facile and improved separation method is crucial. Herein, dopamine was used as a bioadhesive to bind tea polyphenol (TP) onto the surface of a polyvinylidene fluoride (PVDF) membrane to form the first hydrophilic polymer network. Sodium periodate (NaIO4) is considered an oxidising agent for triggering self-polymerisation and can be used to introduce hydrophilic groups via surface manipulation to form the second hydrophilic network. In contrast to the individual polydopamine (PDA) and TP/NaIO4 composite coatings for a hydrophobic PVDF microfiltration membrane, a combination of PDA, TP, and NaIO4 has achieved the most facile treatment process for transforming the hydrophobic membrane into the hydrophilic state. The hierarchical superhydrophilic network structure with a simultaneous underwater superoleophobic membrane exhibited excellent performance in separating various oil-in-water emulsions, with a high water flux (1530 L.m-2 h-1.bar) and improved rejection (98%). The water contact angle of the modified membrane was 0° in 1 s. Moreover, the steady polyphenol coating was applied onto the surface, which endowed the membrane with an adequate antifouling and recovery capability and a robust durability against immersion in an acid, alkali, or salt solution. This facile scale-up method depends on in situ plant-inspired chemistry and has remarkable potential for practical applications.

Development of poly(vinyl alcohol)/starch/ethyl lauroyl arginate blend films with enhanced antimicrobial and physical properties for active packaging.

Active packaging films have emerged as alternatives to replace petroleum-based packaging materials. In this work, poly(vinyl alcohol) (PVA)/starch/ethyl lauroyl arginate (LAE) films possessing enhanced properties were prepared. Scanning electron microscopy (SEM) showed that PVA and starch were compatible, the concentrations of LAE greatly affected the structural integrity. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction showed that the inclusion of LAE did not significantly affect the intermolecular interactions and crystal structures of the polymer matrix. With an increase of the LAE content, the tensile strength (TS) was slightly decreased due to the altered microstructures, the elongation at break (EB) significantly increased ascribed to the synergistic effect of acetic acid, glycerol and LAE. The values of TS and EB were 17.25 MPa and 586.08%, respectively when LAE was 10%. Active films showed good barrier properties from UV while retaining the transmittance in the visible light region. The films containing 1% of LAE exhibited antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), the inhibition zone of bacterial growth gradually expanded with increasing LAE content. This study demonstrates the potential of using LAE as the antibacterial agent for synthesizing natural-based polymeric films for active packaging applications.

Dickkopf 2 promotes proliferation and invasion via Wnt signaling in prostate cancer.

Wnt/ß-catenin signaling dysregulation is involved in tumorigenesis. Furthermore, epigenetic modification of the Dickkopf (DKK) family (DKK1­4) has been shown to be important in the regulation of Wnt signaling. However, the functions and mechanism of DKK2 in the development and progression of prostate cancer remain unclear. Therefore, the present study investigated the role of DKK2 in prostate cancer. The mRNA and protein expression levels of DKK2 in prostate cancer tissues and cells were assessed by reverse transcription­quantitative polymerase chain reaction and western blotting, respectively. The biological function of DKK2 in prostate cancer was investigated using 3­(4,5­dimethylthiazol­2­yl)-2,5­diphenyltetrazolium bromide and transwell invasion assays. DKK2 was demonstrated to be upregulated in prostate cancer tissues and cells, and knockdown of DKK2 suppressed cell proliferation and invasion. Furthermore, small interfering RNA targeting DKK2 inhibited the expression of ß­catenin, cyclin D1 and c­Myc in prostate cancer cells. The present report suggested that DKK2 downregulation suppressed the proliferation and invasion of prostate cancer cells by inhibiting the Wnt/ß­catenin signaling pathway.