[en] A new and facile method was presented to graft molecularly imprinted polymers (MIPs) on carbon nanotubes (CNTs) for 2,4-dichlorophenoxyacetic acid (2,4-D) analysis. In brief, CNTs were firstly coated with a layer of vinyl group modified silica, followed by a common precipitation polymerization with 2,4-D as the template, ethylene glycol dimethacrylate (EGDMA) as the crosslinker and 2,2-azobisisobutyronitrile (AIBN) as the initiator. The imprinted effects obtained by using different monomers were investigated, and the results showed that acrylamide (AM) and styrene as mixed monomers was the best choice. This functionalized material was characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and thermogravimetry (TG), which demonstrated a successful polymerization reaction on CNTs with MIPs grafting ratio of about 80%. The results of static adsorption experiments indicated the imprinted material possessed fast kinetics and good selectivity for 2,4-D molecules. A corresponding analytical method was developed and demonstrated to be applicable for the determination of 2,4-D in environmental water. The recoveries were in the range from 74.6% to 81.2% with relative standard deviation below 7.0%. To be emphasized, the method for MIPs coating proposed herein also provides a significant reference for other radical polymerization reactions based on CNTs.

[en] Nitrogen-sulfur co-doped carbon quantum dots (N, S-CQDs) with good photoluminescence properties were prepared by hydrothermal method using citric acid (CA) and methionine (Met) as precursors. Co-doping with N and S facilitates the electron transfer rate and coordination interaction between N,S-CQDs and Fe(III) ions which acts as a quencher of fluorescence. Based on a simple redox principle, a highly sensitive and selective method for the detection of ascorbic acid (AA) and H₂O₂ was successfully developed. The calibration curves obtained are linear for the current versus AA and H₂O₂ concentration over the range 50–500 μM and 10–140 μM, respectively. And the detection limits for AA and H₂O₂ are 4.2 μM and 1.9 μM, respectively. The quantitative analysis of AA and H₂O₂ in various juices and H₂O₂ disinfectant with Fe³⁺/CQDs or Fe²⁺/CQDs gave the recoveries of 87.8%–117.5% and 99.2%–106.4% with relative standard deviations (RSD) of 1.6–5.1% and 1.7–3.1%, respectively, showing satisfactory results for the determination of AA and H₂O₂ in actual application. The proposed strategy may provide a new pathway to developing inexpensive and sensitive way for the detection of various redox reaction–involved system.

[en] Objective: The aims of the study were to find out the optimal ¹³¹I labeling method with 17-allylamino, 17-demethoxygeldanamycin (17-AAG) and also to study its biodistribution in animals. Methods: ¹³¹I-17-AAG was prepared by the reaction of 17-AAG with Na¹³¹I in the presence of hydrogen peroxide. The labeling efficiency and the stability of ¹³¹I-17-AAG were measured by paper chromatograph. The biodistribution in the ICR normal mice was observed by the blood samplings and major organs that were taken out from mice at 0.5, 1, 4, 8, 24 h after ¹³¹I-17-AAG injection through tail veins. VX2 tumor was also implanted in rabbit liver for in vivo imaging with SPECT. Results: The optimal labeling conditions of 17-AAG with mi were determined. The labeling efficiency was 85.65%. The radiochemical purity of ¹³¹I- 17-AAG in acetoacetate solution was (96.51 ± 0.80)% after purification and its radiochemical purity in normal saline solution was (95.57 ± 0.09)%. The radiochemical purity could keep to 90% in normal saline after 5 d at 4 degree C. The biodistribution study in normal mice showed that the uptake (percentage activity of injection dose per gram of tissue, % ID/g) in liver and kidney was less than that in cholecyst [(3.0963 ± 1.3394) %ID/g] at 0.5 h post-injection, and the uptake in stomach and intestine reached to the highest level at 4 h post-injection. The SPECT images showed that the ¹³¹I-17-AAG was obviously concentrated in the tumor after injection at 2 h and 4 d, 6 d, 14 d with the highest tumor to non-tumor (T/NT) radioactivity ratio of 10.36. Conclusions: The labeling method of 17-AAG with ¹³¹I was successfully established. The ¹³¹I-17-AAG in normal saline had a good stability. The main biodistribution in mice was in digestive system and was excreted through the intestinal tract. The SPECT images showed that ¹³¹I-17-AAG might be a potential target-directed agent to the tumor. (authors)

[en] A novel adsorbent, three-dimensional porous graphene/lignin/sodium alginate nanocomposite (denoted as 3D PG/L/SA) was fabricated by hydrothermal polymerization of lignin and sodium alginate in the presence of graphene oxide (GO) in an aqueous system. Fourier transform infrared spectra, thermo-gravimetric analysis, scanning electron microscopy, and X-ray photoelectron spectroscopy were employed to characterize the morphology and structure of this novel functional PG/L/SA nanocomposite. A series of adsorption experiments for cleanup of Cd(II) and Pb(II) were conducted to investigate the effects of lignin and sodium alginate on the graphene structure. It was found that PG/L/SA showed a significant increase in adsorption capacity contrast to porous graphene (PG). The as-prepared material achieved the adsorption capacity for Cd(II) and Pb(II) of 79.88 and 226.24 mg/g, respectively. Meanwhile, the adsorption process matched well with the Langmuir isotherm model and the pseudo-second-order kinetic model. Studies were also conducted to demonstrate the applicability of the sorbent to the removal of heavy metal ions from metal smelting wastewater.

[en] An electrochemical sensor is described for simultaneous determination of hydroquinone (HQ) and catechol (CT) via differential pulse voltammetry (DPV). It is making use of a ternary composite material prepared from oxidized multiwalled carbon nanotubes, manganese dioxide (MnO₂) and manganese ferrite (MnFe₂O₄). The material was obtained by a one-step hydrothermal reaction and used to modify a glassy carbon electrode (GCE). The composite was characterized by Fourier transform infrared spectroscopy, X-ray powder diffraction, thermogravimetric analysis, X-ray photoelectron spectroscopy and scanning electron microscopy. The peak currents for HQ and CT are highest at 172 and 276 mV (vs. Ag/AgCl) at a pH value of 6.0. Response increases linearly in the 1–400 μM HQ and CT concentration ranges, and the detection limits are 0.64 and 0.48 μM, respectively. The modified GCE is highly selective, repeatable and reproducible. A single sensor was used to make 23 subsequent measurements, and the relative standard deviations were 1.8% and 2.3% for HQ and CT, respectively.

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[en] Objective: 17-allylamino-17-demethoxygeldanamycin (17-AAG) has been developed as a novel heat shock protein 90 (HSP90) inhibitor being used in clinical trials. HSP90 is known as a molecular target for tumor therapy. The goal of this study was to investigate the inhibitive effects of ¹³¹I labeled 17-AAG on human non-small cell lung cancer in xenograft-bearing nude mice. Methods: 17-AAG was labeled with ¹³¹I. Twenty-eight BALB/c nude mice bearing H460 human non-small cell lung carcinoma tumor xenograft were randomly divided into seven groups, one control group and six treatment groups according to the route of administration (via tail vein injection or intratumoral injection) and the doses of injected radio-activity (5.5 MBq x 2 with 8 d interval, 11.0 MBq and 5.5 MBq). Two additional mice were treated with intratumoral injection of Na¹³¹I solution that was served as seintigraphic imaging controls. In each group two mice underwent scintigraphy at 2 h, 6 h, 24 h, 2 d, 3 d, 7 d, 10 d and 16 d. After 16 d the tumor inhibition rate was calculated. Then all of the mice were sacrificed and the tumor tissues were obtained for histological examination and immunohistochemical assay. Results: Persistent accumulation of ¹³¹I-17-AAG in the tumors was seen on seintigraphic images. Tumor inhibiting effect was demonstrated in all treatment groups with varying degrees. The highest tumor inhibition rate (86.77 ± 4.57)% was shown in the group with interval intratumoral injection (5.5 MBq x 2). There was no significant difference of tumor inhibition rates between 5.5 MBq x 2 group (via tail vein injection) and 11.0 MBq group( via tail vein injection, q=1.67, P>0.05). While among the other treatment groups, there was significant difference in tumor inhibition rates( q=3.16-24.34, all P<0.05). The morphologic changes paralleled with the tumor inhibition rates. Tumor cell HSP90α antigen expression rate was significantly lower in the intratumoral injection groups (26.01 ± 3.71)% and in tail vein injection groups (61.51 ± 5.98)% than that of control group (84.13 ± 5.71, t=20.91 and 6.68, all P<0.05). Conclusions: ¹³¹I-17-AAG may effectively inhibit the tumor growth and expression of HSP90α antigen expression in non-small cell lung cancer bearing nude mice. The more prominent anti-tumor effect may be obtained by the administration of interval intratumoral injection. (authors)

[en] Our previous research found that the crude extract of Neo-T. siphonanthun exhibited an effective DPPH (1,1-diphenyl-2-picryhydrazyl) radical scavenging activity. In this study an online rapid screening method, high-performance liquid chromatography-radical scavenging detection-diode array detector-electrospray ionization mass spectrometry (HPLC-RSD- DAD-ESI/MS) system, was developed for screening individual antioxidants from the most active fraction. Accordingly, three isomeric derivatives were detected. The target active compounds were isolated by highspeed counter-current chromatography (HSCCC) with the purity over 99%, and were identified as luteolin-3'-O-β-D-glucopyranoside (1), luteolin-7-O-β-D-glucopyranoside (2) and luteolin-4'- O-β-D-glucopyranoside (3) by analysis of its off-line nuclear magnetic resonance (NMR) spectra. Antioxidant activity of three compounds was assessed by off-line DPPH assay, and all of them showed potent activity. (author)

[en] The highly effective alk-Ti₃C₂/bimetallic Co, Zn embedded N-doped carbon (Co-Zn-NC) composite was fabricated by a convenient self-assembled method strategy and applied to the reduction of 4-nitrophenol(4-NP). Co-Zn-NC nanocage was synthesized by using designed core–shell ZIF-8@ZIF-67 as sacrificial template. The Co-Zn-NC was prepared by pyrolysis of ZIF-8@ZIF-67 at 900 °C with high-specific surface area and hollow structure, which facilitates the dispersion of Co species and produces abundant Co-Nx active sites. In addition, the electrochemical property and specific surface area of Ti₃C₂ were improved by alkaline treatment. As a result, compared with alk-Ti₃C₂ and Co-Zn-NC, the alk-Ti₃C₂/Co-Zn-NC sensor showed higher activity and stability in detecting 4-NP. The alk-Ti₃C₂/Co-Zn-NC sensor has a wide determination range of 2–500 μM and a low detection limit of 0.23 μM for 4-NP. In addition, the newly developed alk-Ti₃C₂/Co-Zn-NC sensor displayed satisfactory reproducibility and good stability in detecting 4-NP in aqueous samples. Graphical abstract

[en] Objective: 17-allylamino-17-demethoxygeldanamycin(17-AAG) is a less toxic analogue of geldanamycin (GA) that retains the tumoricidal features of GA. Same as its parent compound, 17-AAG inhibits several signaling pathways through binding to heat shock protein (HSP) 90, which results in destabilization of signaling complexes and degradation of client proteins in a variety of tumor cell growth. Treatment with 17-AAG was effective to inhibit tumor growth and induce apoptosis in colon cancer, glioblastoma, and breast cancer cell lines. This study aimed at exploring the anti-proliferation effects and mechanism of ¹³¹I labeled 17-AAG on human breast cancer cell line MCF-7. Methods: ¹³¹I-17-AAG was prepared by the reaction of 17-AAG with Na¹³¹I in the presence of hydrogen peroxide. The MCF-7 cells were divided into 5 groups with different additional drugs: group A, dimethyl sulfoxide (DMSO); group B, 370 kBq Na¹³¹I; group C, 2.5 mg/L 17-AAG; group D, 370 kBq ¹³¹I-17-AAG; group E, 370 kBq ¹³¹I-17-AAG + 2.5 mg/L 17-AAG. 3- (4,5-dimethylthiazol-2-yl)-2,5, diphenylte-trazolium bromide (MTT) assay was used to evaluate the effect of growth inhibition of MCF-7 cells. Cell cycle and apoptosis were analyzed by flow cytometry. The change of the expression of Akt2 mRNA in MCF-7 cells was examined by RT-PCR. Results: The labeling yield of ¹³¹I-17-AAG was 83%. The radiochemical purity of ¹³¹I-17-AAG after purification was 96.6%. The specific activity was 1.48 x 10⁵ MBq/μmol. All drugs could significantly inhibit the growth of MCF-7 cells in vitro as the duration lasts longer, especially for group E. After 48 h, sub-G1 peaks detected by flow cytometry were(1.54±0.13)%, (5.72±1.05)%, (12.97±1.44)%, (20.65±1.36)%, (35.39±4.15)% for group A, B, C, D and E, respectively. The experimental groups (B-E) were all significantly higher than the control group (A, all P<0.05). The expression of Akt2 mRNA in treated MCF-7 cells (groups C-E) were all lower than that of the control group (A), especially for group E. Conclusions: ¹³¹I-17-AAG could suppress the growth of human breast cancer cell line MCF-7 and hasten the apoptosis. It could significantly suppress the expression of Akt2 mRNA. Combined with 17-AAG, ¹³¹I-17-AAG could improve the effect of radiotherapy. (authors)

[en] Advanced oxidation processes by the activation of peroxymonosulfate (PMS) have been widely concerned for the enhanced degradation of organic pollutants. In this work, CuCoFe calcined layered double hydroxides (CuCoFe-CLDH) were successfully prepared via a simple method, and its lamellar structure and spinel-like composites were proved by using XRD, SEM and FT-IR. The CuCoFe-CLDH was used to activate PMS to produce many active species for the degradation of p-nitrophenol (PNP) under ultraviolet irradiation (UV). At the optimal conditions of CuCoFe-CLDH dosage 0.3 g/L and PMS dosage 0.3 g/L, it was discovered that the degradation efficiency of 20 mg/L PNP was about 95.11% under UV light within 30 min. In addition, the degraded reaction accorded with the pseudo-first-order kinetic behaviors, and it was found that SO₄^·− and ·OH radicals were effective active species in the quenching experiments under the CuCoFe-CLDH/UV/PMS system. The CuCoFe-CLDH could still keep above 93% after five continuous recycles, and also showed remarkable reusability and stability in accord with the characterization analysis of fresh and used materials. Briefly, this work could be a promising method for the treatment of the phenol-bearing wastewater and support theoretical foundation for PMS activation.