RSC Advances

Chen, Bingjie; Zhang, Shuhua; Zhang, Qingsong; Mu, Qifeng; Deng, Lingli; Chen, Li; Wei, Yen; Tao, Lei; Zhang, Xiaoyong; Wang, Ke

doi: 10.1039/c5ra16811bpmid: N/A

Learning from the idea of food fermentation, a facile and environmentally benign method has been developed for the preparation of 3D microorganism inspired hydrogels (MIH). To clarify the effect of temperature on the fermentation capacity of yeast, bubble coalescence, gelation time, pore shape and swelling behavior of MIH, a series of temperatures from 25 °C to 50 °C were set to synthesise super-/macro-porous polyacrylamide (PAM) hydrogels with fast response and hierarchical pore structure via an environmental friendly fermentation method. It is found that the gelation process of acrylamide and CO2 gas foaming process of yeast fermentation play decisive roles in controlling the pore structure and swelling behavior of PAM hydrogels. A mutual benefit on the fermentation and unique porous structure make HSYT hydrogels potentially applicable for drug delivery systems, food industries and chemical separation.

Kumar, Vinod; Rana, Hemlata

doi: 10.1039/c5ra18641bpmid: N/A

We present a highly selective and sensitive detection protocol for the chemical warfare agent sulfur mustard (SM). The chromogenic and fluorogenic system uses a squaraine dye (SQ) that not only detects SM but also discriminates it from other chemical warfare agents (CWAs) and potent electrophilic interferents. A water soluble dithiol, 2-(3,5-bis(mercaptomethyl)phenoxy)acetic acid 1, in the presence and absence of SM, behaves differently towards the squaraine dye (SQ) to give different chromogenic and fluorogenic responses. With an aim to mimic real-life scenarios for the onsite and offsite detection, the sensing protocol was further implemented in spiked water and soil samples, on surfaces, and in the gas phase. The lower detection limit (much lower than the lethal dose) of both visual inspection and the fluorescence technique will be highly useful to mankind in order to sensitively detect SM.

Zhao, Yang; Zhong, Zhaoxiang; Low, Ze-Xian; Yao, Zhong

doi: 10.1039/c5ra18200jpmid: N/A

Carbon nanotubes (CNTs) are very small diameter fibers that have the potential to be integrated into filters to further increase particle capture efficiency. In this work, we used a chemical vapor deposition (CVD) method to create the carbon nanotubes/ceramic composite filter by growing multi-walled carbon nanotubes (MWCNTs) on a porous alumina ceramic membrane. Compared with the pristine alumina ceramic membrane, although the mean pore size and porosity of composite filter decreased 9.2% and 11.0% respectively, the resulting composite filter showed significant improvements in air filtration performance, owing to the dramatical increase of specific area by two order of magnitude and enhancement of wall slip flow effect over CNTs. The pressure drop across the composite filters decreased about 62.9% with respect to that of the pristine filters, while the filtration efficiency of the composite filters at the most penetrating particle size (MPPS) has been increased to 99.9999% (reached the standard of ULPA filters), leading to an obvious higher quality factor (Qf). The presence of CNTs strongly inhibits the propagation of bacteria on the filters with an antibacterial rate of 97.86% and show high water repellency (water contact angle of 148.2°). These results make the composite filter very promising for multifunctional air filtration applications.

Pattnaik, Satyanarayan; Swain, Kalpana; Rao, Jupally Venkateswar; Varun, Talla; Prusty, K. Baikuntha; Subudhi, Sanjeev Kumar

doi: 10.1039/c5ra20411apmid: N/A

With the increasingly lipophilic nature of candidate drugs, solubility and dissolution rates have become the limiting factors that affect bioavailability of oral and parenteral formulations. The purpose of the study is to improve the dissolution rate of aceclofenac through a nanonization technique. In the present work, particle engineering was carried out to obtain pure drug nanocrystals of aceclofenac using a standard, simple and scalable bottom up technique to overcome its poor dissolution behavior employing different classes of polymeric stabilizers. The physicochemical properties were evaluated including particle size distribution, powder X-ray diffractometry, scanning electron microscopy and in vitro dissolution studies. Intestinal absorption studies were also carried out to assess the effectiveness of the fabricated nanocrystals. The concentration and type of polymer influenced the particle size and dissolution velocity of aceclofenac. Among the stabilizers studied, methyl cellulose (0.3% w/v) was found most efficient which lead to highest dissolution (88.27 ± 2.053%) with significant reduction in particle size. The intestinal permeation studies indicated significantly (p < 0.05) higher permeation of drug from the nanocrystals. Semi synthetic non ionic polymers were found very effective in reducing the particle size (preventing growth of crystals), improving the dissolution and intestinal permeation of aceclofenac from the engineered nanocrystals.

Shaabani, Ahmad; Hezarkhani, Zeinab; Badali, Elham

doi: 10.1039/c5ra16608jpmid: N/A

A novel domino oxidative Ugi-type three-component reaction of aromatic hydrocarbons (OU-3CR) has been investigated with aromatic hydrocarbons of petroleum naphtha using two biopolymer supported MnO2 nanostructured catalysts, MnO2@cellulose–SO3H and MnO2@wool–SO3H, for the synthesis of α-amino amides, 3,4-dihydroquinoxalin-2-amine, 4H-benzo[b][1,4]thiazin-2-amine, and cyanophenylamino-acetamide derivatives. Nano-MnO2@cellulose–SO3H and nano-MnO2@wool–SO3H were used as biodegradable oxidation and solid acid catalysts. The best results for oxidation and condensation processes are obtained with MnO2@cellulose–SO3H and MnO2@wool–SO3H, respectively. To the best of our knowledge this approach can be considered as the first example of OU-3CR of alkyl arenes with a nano-MnO2 catalyst which would be very useful from a practical point of view.

Ding, Guangqian; Li, Jie; Gao, Guoying

doi: 10.1039/c5ra18369cpmid: N/A

The thermoelectric (TE) conversion efficiency is always limited by a low TE figure of merit (ZT). Improving ZT requires both a high power factor (PF) and a low thermal conductivity. So far, however, most efforts to improve ZT have been made by reducing the thermal conductivity rather than maximizing the PF. Recently, band engineering which can effectively solve the paradox between the density-of-states effective mass and carrier mobility, has been treated as an efficient approach to improve ZT by maximizing the PF. In this paper, based on first-principles and the Boltzmann transport theory, we calculate the electronic structure and thermoelectric properties of classical IV–VI semiconductors MTe and MSe (M = Pb, Sn, Ge). We find that band engineering of multiple band degeneracy induced by engineering the conduction bands near the Fermi level can increase the room temperature n-type PF around 3 to 8 times. The present work is useful in thermoelectrics and will attract more research interest in optimizing the TE performance by band engineering.

Tang, Chunni; Liu, Enzhou; Fan, Jun; Hu, Xiaoyun; Ma, Yongning; Wan, Jun

doi: 10.1039/c5ra18096apmid: N/A

A graphitic-C3N4-hybridized Ag3PO4 tetrahedron with reactive {111} facets was prepared though a facile solvent evaporation method and applied for the photocatalytic degradation of methyl blue (MB) in aqueous solution and removal of NO at the indoor air level under visible light irradiation (>400 nm). In addition to the superior photocatalytic performance of the highly reactive {111} facets of tetrahedral Ag3PO4, the hybridization with g-C3N4 was confirmed to further improve the photocatalytic activity, and the content of g-C3N4 had a great influence on the photocatalytic activity. The photocatalytic activity enhancement of g-C3N4/Ag3PO4 {111} hybrid photocatalysts could be ascribed to the efficient separation of electron–hole pairs through a Z-scheme system composed of Ag3PO4, Ag and g-C3N4, in which Ag particles acted as the charge separation center. Furthermore, h+ and O2˙− played the major roles in the photocatalysis process. This work suggested that the synthesized g-C3N4/Ag3PO4 {111} hybrid would be a promising visible light driven photocatalytic material for environmental remediation.

Okochi, M.; Sugita, T.; Tanaka, M.; Honda, H.

doi: 10.1039/c5ra15174kpmid: N/A

A molecular peptide beacon was designed for fluorescence detection of IgG in a homogeneous assay. pH-triggered detection of IgG was demonstrated using a fluorophore-labeled peptide that incorporated a binding site in the Fc region of IgG with a complementary quenching site.

Kolchina, L. M.; Lyskov, N. V.; Kazakov, S. M.; Mazo, G. N.; Antipov, E. V.

doi: 10.1039/c5ra17763dpmid: N/A

How to affect the transport properties of complex oxides was considered using the uncommon example of Pr2−xLaxCuO4. It was established that appropriate La doping in Pr2CuO4 leads to a noticeable increase in high-temperature electrical conductivity. The reason for such changes are discussed from the viewpoint of possible charge redistribution in Pr2−xLaxCuO4.

Wen, Qiuxiang; Zhuang, Jia; He, Quangui; Deng, Yang; Li, Haimin; Guo, Jiang

doi: 10.1039/c5ra15054jpmid: N/A

ZnO, SnO2, simple mixed ZnO/SnO2 (S-ZnO/SnO2) and complex composite ZnO/SnO2 (C-ZnO/SnO2) photoanode films were prepared and applied in DSSCs using a Two-step Solid State Reaction (TSSR) method. The photoanode films were characterized using SEM, XRD and a surface area analyzer, and their optical properties were measured with a UV-vis spectrophotometer. The voltage–current density curve (J–V) and incident photon-to-current conversion efficiency (IPCE) were tested to characterize the performance of the different cells. The results demonstrate that the C-ZnO/SnO2 photoanode shows a better uniform film structure, larger surface area and dye loading, which causes the device to have a higher power conversion efficiency (PCE) of 5.36% compared to the other three. A lower electron recombination rate and longer electron lifetime are confirmed for the device based on the C-ZnO/SnO2 photoanode film by analysis with electrochemical impedance spectroscopy (EIS).