Flower-like molybdenum disulfide/cobalt ferrite composite for the extraction of benzotriazole UV stabilizers in environmental samples.

Benzotriazole UV stabilizers (BUVSs) are a class of emerging contaminants of concern; the development of rapid and convenient monitoring method for these trace-level pollutants in waters is of crucial significance in environmental science. Here, a novel magnetic flower-like molybdenum disulfide/cobalt ferrite nanocomposite (MoS2/CoFe2O4) was synthesized by hydrothermal reaction. Compared with the conventional Fe3O4-based magnetic composites, the proposed material just required a minimum consumption of Co/Fe towards the equivalent of MoS2 while providing superior magnetization performance. Taking advantages of high adsorption capacity, extraordinary stability, and repeatability in construction, MoS2/CoFe2O4 was applied to the extraction to BUVSs. The enrichment factors of three BUVSs were in the range 164-193 when 20 mL of environmental water sample was loaded on 40 mg of the adsorbent. MoS2/CoFe2O4 could be regenerated and recycled at least 10 cycles of adsorption/desorption with recoveries of 80.1-111%. The method of MoS2/CoFe2O4-based extraction coupled with high-performance liquid chromatography-variable wavelength detector was applied to the monitoring of BUVSs in seawater, lake water, and wastewater, which gave detection limits (S/N = 3) of 0.023-0.030 ng·mL-1 and recoveries of 80.1-110%. The intra-day and inter-day precisions (relative standard deviation, RSDs, n = 3) were in the range 1.6-7.5% and 3.2-11.5%, respectively. The approach is an alternative for efficient and sensitive extraction and determination of trace-level environmental pollutants in waters.

In-situ fabrication of zeolite imidazole framework@hydroxyapatite composite for dispersive solid-phase extraction of benzodiazepines and their determination with high-performance liquid chromatography-VWD detection.

A novel zeolite imidazole framework@hydroxyapatite composite (ZIF-8@HAP) was constructed via in-situ growth and developed for efficient dispersive solid-phase extraction (DSPE) of three benzodiazepines from urine samples. The prepared composite was characterized by scanning electron microscopy, energy-dispersive spectrometer, Fourier-transform infrared spectrometry, X-ray diffractometry, zeta potential analyzer, and nitrogen adsorption-desorption experiment. Characterization results showed typical dodecahedron ZIF-8 crystals that were uniformly located on the surface of rod-like HAP. The combination of ZIF-8 and HAP made the surface area significantly enhanced from 4.68 to 205.44 m2 g-1. Compared with a commercial C18 adsorbent, ZIF-8@HAP exhibited superior removal performance for interfering components from urine and offered better extraction properties for the analytes. The prepared ZIF-8@HAP was applied as an adsorbent in DSPE, and the main experimental parameters, including pH and ionic strength of solution, adsorbent amount, adsorption time, elution solvent, and volume, were investigated. Under optimal conditions, the adsorption for 250 ng mL-1 of each analyte in 4 mL of urine was accomplished within 2 min using 60 mg of adsorbent. The method of ZIF-8@HAP-based DSPE followed by high-performance liquid chromatography gave enhancement factors of 13.3-15.3, linear ranges of 2.5-500 ng mL-1, and limits of detection (S/N = 3) of 0.7-1.4 ng mL-1. The relative recoveries at three spiked levels ranged from 88.7 - 102% with intra-day and inter-day precisions from 3.0 - 10.3% and 2.3 - 12.3%, respectively. These results indicated that the proposed strategy had promising applicability for convenient, rapid, and efficient determination of benzodiazepines in urine samples.Graphical abstract In-situ fabrication of ZIF-8@HAP composite for dispersive solid-phase extraction of benzodiazepines in urine samples.

Resveratrol alleviate the injury of mice liver induced by cadmium sulfide nanoparticles.

Cadmium sulfide nanoparticle (Nano-CdS) is a kind of important semiconductor material with special photochemistry property. With the Nano-CdS being widely used, the security problems it caused have been catching more and more attention. This study aims to explore the possible mechanism of liver injury induced by Nano-CdS and whether resveratrol can reduce the damage. In this study, male BALB/C mice were treated with Nano-CdS with a diameter of 20 to 30 nm and a length of 80 to 100 nm. It turned out that the mice liver inflammatory cells infiltrated, the liver tissue and the ultrastructure changed; The activities of T-AOC and GSH were suppressed (n = 6, P < 0.05) and the content of lipid peroxide (MDA) increased (n = 6, P < 0.05). Besides, Nano-CdS decreased the mRNA expression level of Sirt1 and FoxO1 genes in liver tissue (n = 3, P < 0.05). All the changes in the index were reversed by resveratrol. The mRNA expression level of FoxO3a showed no significant difference between the control group and the Nano-CdS group. But under the protection of resveratrol, the mRNA expression level of FoxO3a was higher than that in the control and Nano-CdS groups (n = 3, P < 0.05). Results suggest that Nano-CdS can cause oxidative damages to liver tissues in mice, in which process that the Sirt1 and FoxO1 genes may participate, and the damage can be reversed by resveratrol which may be a potential cure for oxidative damage to nanomaterials.

Enantioselective Ir-Catalyzed Allylic Alkylation of Racemic Allylic Alcohols with Malonates.

Ir-catalyzed enantioselective allylic alkylation of branched racemic allylic alcohols with malonates is described. Enabled by Carreira's chiral Ir/(P, olefin) complex, the method described allows allylic substitution with various aromatic alcohols and malonates with excellent enantioselectivity. The malonates could be used directly as efficient nucleophiles without the need of preactivation.

Total Synthesis of (-)-Actinophyllic Acid Enabled by a Key Dual Ir/Amine-Catalyzed Allylation.

A synthetic strategy for the catalytic asymmetric total synthesis of (-)-actinophyllic acid is described. This highly efficient and enantioselective approach allows the rapid installation of the four contiguous chiral centers (C16, C15, C20, and C19) by way of a dual Ir/amine catalytic allylation of 2-indolyl vinyl carbinol 6 and an aldol reaction of resultant chiral aldehyde 4a with 2-pyrrolidinone 5. The key indol-3-ylmethanamine moiety and 1-azabicyclo[4.2.1]nonane ring system were readily generated through a selective Mannich-like cyclization and an intramolecular N-alkylation, respectively.

[Laparoscopy-assisted radical gastrectomy with D2 lymph node dissection for gastric cancer in the elderly].

OBJECTIVE: To evaluate the feasibility and efficacy of laparoscopy-assisted radical gastrectomy with D2 lymph node (LN) dissection for elderly patients with gastric cancer. METHODS: From January 2007 to December 2009, 255 gastric cancer patients aged over 65 years underwent D2 LN dissection. Of these, 116 patients underwent laparoscopy-assisted radical gastrectomy (LAG group), while 139 patients underwent conventional open gastrectomy (OG group). The recovery and complication rate were compared between the two groups. Risk factors associated with postoperative complications were investigated by univariate and multivariate analyses. RESULTS: Compared to the OG group, the mean blood loss and number of patients who required blood transfusion were less, and the time to first flatus, the time to resume soft diet, and postoperative hospital stay were shorter in the LAG group (all P<0.01). However, the operation time and the mean number of LN retrieval were not significantly different between the two groups (both P>0.05). The postoperative morbidity in the LAG group was 15.5% (18/116), lower than that in OG group [28.1% (39/139), P<0.05]. Logistic regression analysis revealed that there were three significant factors associated with postoperative complications such as laparoscopy-assisted gastrectomy (P<0.05), operation time (P<0.01), and preoperative comorbidity (P<0.01). Operation time (P<0.05) and preoperative comorbidity (P<0.01) were independent risk factors for complication in laparoscopy-assisted radical gastrectomy of elderly patients. The mean survival time of LAG and OG were 23.0 months and 22.5 months, respectively, and the difference was not statistically significant (P>0.05). CONCLUSIONS: Laparoscopy-assisted radical gastrectomy with D2 LN dissection is oncologically compatible with open gastrectomy in elderly patients with gastric cancer less invasive. Operation time and preoperative comorbidity are independent risk factors for complication in laparoscopy-assisted radical gastrectomy of elderly patients.

[Growth inhibitory effects of lipofectamine-mediated DCC gene on ovarian epithelial carcinoma].

OBJECTIVE: To study the inhibitory effects of lipofectamine-mediated deleted colorectal carcinoma gene on ovarian epithelial carcinoma (ovarian cancer) cell line SKOV3. METHODS: We constructed a recombinant eukaryotic expression vector pcDNA3.1 (+)-DCC containing exogenous human DCC cDNA and vector with neomycin resistance gene, which were introduced by lipofectamine-mediated gene transfection into SKOV3 cell line that does not express DCC endogenously, thus forming SKOV3/DCC. Therefore, the experimental cells were classified into SKOV3/DCC, SKOV3/Neo and SKOV3. By using reverse transcriptase-polymerase chain reaction and immunocytochemistry, the expression of DCC mRNA and its protein were examined. RESULTS: Exogenous DCC had successfully been transferred into SKOV3 cells and obtained permanent expression. The growth speed of SKOV3/DCC was slower than the other two groups, there was significant difference between them (P < 0.01). SKOV3/DCC clones number was 38 +/- 8, while SKOV3 and SKOV3/Neo were 192 +/- 8 and 186 +/- 10, respectively, there was significant difference between them (P < 0.01). The percentage of G(1) phase cells increased to 78.0%, which that of S phase decreased to 5.3% by analyzing cell cycle, there was significant difference between them (20.0% and 3.2%, P < 0.01). The ultrastructural changes of the cells were observed under electron microscope, revealing growth retardation. CONCLUSION: DCC gene played an important role in generation and development of ovarian carcinomas.