A facile and green route to fabricate fiber-reinforced membrane for removing oil from water and extracting water under slick oil.

Except the good separation performance, the membranes used for oil-water mixture separation should be fabricated with as little wastewater produced as possible. Thus, we proposed a green tactic--water vapor induced phase inversion to prepare the high-strength and superhydrophilic/underwater superoleophobic nonwoven fabric-based cotton/PA6/PAN membranes which is based on the polymer/solvent/nonsolvent ternary system analysis. Differing from adding additives in polymer solution or coagulation bath, above proposed strategy has an "subtractive effect" with the advantages of constructing three-dimensional porous structure and greatly reducing the organic wastewater produced during preparation process. Moreover, the obtained cotton/PA6/PAN membranes exhibited unexpected performances for separating oil-in-water emulsions. An ultrahigh permeation flux of up to 478,000 L m-2 h-1 bar-1 with a separation efficiency of > 99.9% was obtained under the driving pressure of 1.6 KPa, which was one order of magnitude higher than the conventional separation membranes with similar properties. In addition, it is surprising that the cotton/PA6/PAN membranes can also extract water from the slick oil/water immiscible mixture. Therefore, it is expected that the cotton/PA6/PAN membranes can be used in practical oily wastewater purification.

One-Pot Synthesis of Pd@PtnL Core-Shell Icosahedral Nanocrystals in High Throughput through a Quantitative Analysis of the Reduction Kinetics.

The rational design and implementation of a one-pot method is reported for the facile synthesis of Pd@PtnL (nL denotes the number of Pt atomic layers) core-shell icosahedral nanocrystals in a single step. The success of this method relies on the use of Na2 PdCl4 and Pt(acac)2 as the precursors to Pd and Pt atoms, respectively. Our quantitative analysis of the reduction kinetics indicates that the PdII and PtII precursors are sequentially reduced with a major gap between the two events. Specifically, the PdII precursor is reduced first, leading to the formation of Pd-based icosahedral seeds with a multiply-twinned structure. In contrast, the PtII precursor prefers to take a surface reduction pathway on the just-formed icosahedral seeds. As such, the otherwise extremely slow reduction of the PtII precursor can be dramatically accelerated through an autocatalytic process for the deposition of Pt atoms as a conformal shell on each Pd icosahedral core. Compared to the conventional approach of seed-mediated growth, the throughput for the one-pot synthesis of Pd@PtnL core-shell nanocrystals can be increased by more than 30-fold. When used as catalysts, the Pd@Pt4.5L core-shell icosahedral nanocrystals show specific and mass activities of 0.83 mA cm-2 and 0.39 A mgPt -1 , respectively, at 0.9 V toward oxygen reduction. The Pt-based nanocages derived from the core-shell nanocrystals also show enhanced specific (1.45 mA cm-2 ) and mass activities (0.75 A mgPt -1 ) at 0.9 V, which are 3.8 and 3.3 times greater than those of the commercial Pt/C, respectively.

Platinum Cubic Nanoframes with Enhanced Catalytic Activity and Durability Toward Oxygen Reduction.

We report the synthesis and electrocatalytic properties of Pt cubic nanoframes with ultrathin ridges less than 2 nm in thickness. The nanoframes were synthesized through site-selected deposition of Pt onto the corner and edge sites of Pd nanocubes, followed by selective removal of the Pd cores via chemical etching. The Br- ions chemisorbed on the side faces of a Pd nanocube played a critical role in enabling the siteselected deposition. In addition, the kinetics of deposition and the diffusion of Pt adatoms was optimized by carefully controlling the injection rate of the Pt precursor and the reaction temperature, respectively, to obtain the frame-like structure. When benchmarked against a commercial Pt/C comprised of Pt particles 2-3 nm in size, the Pt frame/C catalyst exhibited not only enhanced mass activity toward oxygen reduction, but also substantially improved catalytic durability. In an accelerated durability test, the Pt frame/C catalyst showed a mass activity more than 6× greater than for the Pt/C reference after 20 000 cycles of repeated potential sweeping. This improvement can be largely attributed to the frame-like structure, which is unique in suppressing both the detachment and aggregation of catalytic particles owing to the significantly enhanced interaction with carbon support.

Quantitative Analysis of the Reduction Kinetics Responsible for the One-Pot Synthesis of Pd-Pt Bimetallic Nanocrystals with Different Structures.

We report a quantitative understanding of the reduction kinetics responsible for the formation of Pd-Pt bimetallic nanocrystals with two distinctive structures. The syntheses involve the use of KBr to manipulate the reaction kinetics by influencing the redox potentials of metal precursor ions via ligand exchange. In the absence of KBr, the ratio between the initial reduction rates of PdCl4(2-) and PtCl4(2-) was about 10.0, leading to the formation of Pd@Pt octahedra with a core-shell structure. In the presence of 63 mM KBr, the products became Pd-Pt alloy nanocrystals. In this case, the ratio between the initial reduction rates of the two precursors dropped to 2.4 because of ligand exchange and, thus, the formation of PdBr4(2-) and PtBr4(2-). The alloy nanocrystals took a cubic shape owing to the selective capping effect of Br(-) ions toward the {100} facets. Relative to the alloy nanocubes, the Pd@Pt core-shell octahedra showed substantial enhancement in both catalytic activity and durability toward the oxygen reduction reaction (ORR). Specifically, the specific (1.51 mA cm(-2)) and mass (1.05 A mg(-1) Pt) activities of the core-shell octahedra were enhanced by about four- and three-fold relative to the alloy nanocubes (0.39 mA cm(-2) and 0.34 A mg(-1) Pt, respectively). Even after 20000 cycles of accelerated durability test, the core-shell octahedra still exhibited a mass activity of 0.68 A mg(-1) Pt, twice that of a pristine commercial Pt/C catalyst.

Therapeutic application of injectable thermosensitive hydrogel in preventing local breast cancer recurrence and improving incision wound healing in a mouse model.

Many drug delivery systems (DDSs) have been investigated for local targeting of malignant disease with the intention of increasing anti-tumor activity and minimizing systemic toxicity. An injectable thermosensitive hydrogel was applied to prevent locoregional recurrence of 4T1 breast cancer in a mouse model. The presented hydrogel, which is based on poly(ethyleneglycol)-poly(ε-caprolactone)-poly(ethylene glycol) (PEG-PCL-PEG, PECE), flows freely at normal temperature, forms a gel within seconds in situ at body temperature, and eventually releases the drug in a consistent and sustained fashion as it gradually biodegrades. Locoregional recurrence after primary tumor removal was significantly inhibited in mice treated with the paclitaxel (PTX)-loaded PECE hydrogel subcutaneously (9.1%) administered, compared with the blank hydrogel (80.0%), systemic (77.8%) and locally (75.0%) administered PTX, and the control group (100%) (P < 0.01). In addition, tensile strength measurements of the surgical incisions showed that the PECE hydrogel accelerates wound healing at postoperative day 7 (P < 0.05), and days 4 and 14 (P > 0.05), in agreement with histopathological examinations. This novel DDSs represents a promising approach for local adjuvant therapy in malignant disease.

Low-dose endostatin normalizes the structure and function of tumor vasculature and improves the delivery and anti-tumor efficacy of cytotoxic drugs in a lung cancer xenograft murine model.

INTRODUCTION: To some extent endostatin normalizes tumor vasculature. However, the optimum time window and optimum drug dose for tumor vascular normalization need to be explored. Here we investigate the effect of low-dose endostatin on the structure and function of tumor vasculature and the delivery and anti-tumor efficacy of cytotoxic drugs. METHODS: A lung cancer xenograft murine model was treated with low-dose endostatin for 10 days. The structure and function of the tumor vasculature were evaluated using various techniques. Paclitaxel was added in different schedules. RESULTS: Endostatin caused a significant reduction in microvessel density. Tumor vascular walls after endostatin treatment were better structured. Tumor blood perfusion was increased on day six after endostatin administration. On days three, six, and 10, Evans blue extravasation into the parenchyma of tumors was decreased. On days three and six, endostatin-treated mice had greater paclitaxel delivery. The time window of vascular normalization was approximately three to six days. On days one to three, and days four to six, combined therapy with paclitaxel significantly inhibited tumor growth. CONCLUSIONS: Low-dose endostatin aids normalization of tumor vasculature. This resulted in improved delivery of cytotoxic drugs to the tumor, which closely correlates with synergistic efficacy when combined with paclitaxel during the normalization window.

Effect of endostatin on preventing postoperative progression of distant metastasis in a murine lung cancer model.

AIMS AND BACKGROUND: The relapse and metastasis of cancer remain a predominant cause of death after surgical removal of the primary tumor. There is a positive linkage between the postoperative upregulation of systemic angiogenic activity and distant tumor metastasis. In the present study, we established a spontaneous metastasis model and investigated whether antiangiogenic therapy using endostatin could prevent the progression of distant metastasis after removal of the primary tumor. METHODS: Female C57BL/6 mice were implanted subcutaneously with 1 × 106 Lewis lung cancer cells. Twenty days after implantation of the cancer cells, the primary tumor was removed and the mice were randomly divided into three groups. The NS group received normal saline, the L-ES group received 3 mg/kg endostatin, and the H-ES group received 20 mg/kg endostatin intravenously daily for 10 days. The effect of endostatin on lung metastases and the survival time of the mice were observed. Flow cytometry and immunohistochemistry were carried out to assess the angiogenic activity. The serum endostatin levels in peripheral blood were measured using an enzyme-linked immunosorbent assay. RESULTS: The mean number of metastatic pulmonary nodules and the mean net lung weight in the NS, L-ES and H-ES groups was 10.2, 2.8 and 4.0, and 0.55 g, 0.31 g and 0.36 g, respectively. The difference between the NS group and the endostatin-treated groups was statistically significant (P <0.05). The endostatin-treated mice showed prolonged overall survival (P <0.05). Compared with the NS group, the endostatin-treated groups had lower levels of circulating endothelial cells in peripheral blood and showed a decrease in microvessel density in the metastatic tumors, with a more marked reduction in the L-ES group (P <0.05). The systemic presence of endostatin was gradually increased with the continued administration of endostatin to the mice. CONCLUSIONS: Antiangiogenic therapy with endostatin is effective in inhibiting the postoperative progression of distant metastasis.

[Detection of anisakid nematodes by an SYBR green I real-time PCR].

OBJECTIVE: To establish an SYBR Green I real-time quantitative PCR method for the detection of anisakid nematodes with zoonotic potential from Taiwan Strait. METHODS: Anisakid larvae of six species (Anisakis simplex, A. physeteris, Raphidascaris trichiura, Contracaecum aduncum, C. muraenesoxi, and Contracaecum sp., a predominant species in fishes in the strait) were obtained from the guts of marine fishes and identified chiefly based on the morphological features. The ITS-2 rDNA sequences from the larvae were amplified by PCR using universal primers, then cloned and bidirectionally sequenced. According to these sequences, six specific forward primers were designed and synthesized. Specificity was determined by a series of conventional PCR respectively, the ITS-2 sequences amplified above were cloned into T vector which was subsequently transformed into E. coli DH5alpha. Following extraction and identification, the positive recombinant plasmid was used as quantitative template to generate standard curve and melt curve. Sensitivity and reproducibility were determined. RESULTS: All the 6 standard curves established by the recombinant plasmids showed adequate linear relationship between threshold cycle (Ct) and template concentration. Melt curves were specific and all the 6 correlation coefficients were above 0.998. In the reproducibility test, the coefficients of variation (cv) of Ct values for detection of the 6 nematodes ranged between 0.18% and 2.80%, and the cv of the inter-assay ranged between 0.55% and 1.94%. The sensitivity of the real-time PCR was 1 x 10(2) copies/microl, about 100 times higher than the conventional PCR assays. The real-time quantitative PCR detection needed only 3.5 hours from the sample treatment to result report. CONCLUSION: An SYBR Green I fluorescent quantitative PCR has been developed for detecting anisakid nematodes with adequate sensitivity and specificity.