A Microporous Hydrogen Bonded Organic Framework for Highly Selective Separation of Carbon Dioxide over Acetylene.

The separation of acetylene (C2 H2 ) from carbon dioxide (CO2 ) is a very important but challenging task due to their similar molecular dimensions and physical properties. In terms of porous adsorbents for this separation, the CO2 -selective porous materials are superior to the C2 H2 -selective ones because of the cost- and energy-efficiency but have been rarely achieved. Herein we report our unexpected discovery of the first hydrogen bonded organic framework (HOF) constructed from a simple organic linker 2,4,6-tri(1H-pyrazol-4-yl)pyridine (PYTPZ) (termed as HOF-FJU-88) as the highly CO2 -selective porous material. HOF-FJU-88 is a two-dimensional HOFs with a pore pocket of about 7.6 Å. The activated HOF-FJU-88 takes up a high amount of CO2 (59.6 cm3 g-1 ) at ambient conditions with the record IAST selectivity of 1894. Its high performance for the CO2 /C2 H2 separation has been further confirmed through breakthrough experiments, in situ diffuse reflectance infrared spectroscopy and molecular simulations.

Electrical bistability based on metal-organic frameworks.

Electrical bistability existing in biochemical networks is critical for the proper functionalization of living systems. The development of artificial materials with electrical bistability begun to attract much interest due to their broad application prospects, especially in the field of memristors. Metal-organic frameworks (MOFs) have advantages in regular pores, crystallinity, structural designability and easy functionalization, which can promote the construction of novel MOF-based memristors and facilitate a better understanding of switching mechanisms. Here, we highlight recent advances in electrically bistable MOFs as memristors, and discuss their switching mechanisms, including interfacial reaction, proton-transfer mechanism, metal ion migration, charge trapping/detrapping and other mechanisms. Challenges and future perspectives are also presented.

Light actuated stable radicals of the 9-anthracene carboxylic acid for designing new photochromic complexes.

The photogeneration of stable radicals is important but still challenging in the field of optical switching, displays, and other devices. Herein, crystalline 9-anthracene carboxylic acid (9-AC) and a mononuclear complex constructed from this ligand were for the first time discovered to show radical-induced photochromism and photomagnetism after Xe lamp light irradiation. This study finds a simple radical-actuated photochromic molecule for constructing a novel system of photochromic materials.

Two Photochromic Complexes Assembled by a Nonphotochromic Ligand: Photogenerated Radical Enhanced Room-Temperature Phosphorescence.

Stimulating tunable room-temperature phosphorescence (RTP) is still a challenge in photochromic systems, which is vital for multifunctional coordination materials. Herein, we synthesized two new photochromic chain complexes through self-assembly of the nonphotochromic 1,3,5-tris(4-pyridyl)benzene ligand, diphosphonate, and Ln(III) ions (1 for Ln(III) = Dy and 2 for Ln(III) = Gd). Both compounds showed fast photoresponses with the color turning from yellow to dark gray with a reversible decoloration by heating or storage in the dark. The electron transfer photochromic behavior with the generated stable radicals was further confirmed by the room-temperature UV-vis and electron paramagnetic resonance spectra. Furthermore, via tuning the generation and disappearance of stable radicals, reversible room-temperature fluorescence and phosphorescence for both compounds were switched by light irradiation and a thermal treatment, with an enhanced intensity for RTP and a decrease in fluorescence during the duration of Xe-lamp light irradiation. This work provides a new strategy that photogenerated radicals could promote and enhance RTP properties in functional materials.

Preparation of PP-g-(AA-MAH) Fibers Using Suspension Grafting and Melt-Blown Spinning and its Adsorption for Aniline.

This paper uses polypropylene (PP) as the matrix and acrylic acid (AA) and maleic anhydride (MAH) as functional monomers to prepare PP-g-(AA-MAH) fibers by suspension grafting and melt-blown spinning technology that are easy to industrially scale-up. The fibers can be used to adsorb aniline. Results showed that the grafting ratio reached the maximum of 12.47%. The corresponding optimal conditions were grafting time of 3 h, AA: MAH = 0.75, total monomer content of 55%, benzoyl peroxide 1.4%, xylene concentration of 6 mL/g PP, and deionized water content of 8 mL/g PP. Owing to its good fluidity and thermal stability, the product of suspension grafting can be used for melt-blown spinning. Infrared spectroscopic and nuclear magnetic resonance spectroscopic analyses indicated that AA and MAH were successfully grafted onto PP fibers. After grafting, the hydrophilicity of PP-g-(AA-MAH) fiber increased. Therefore, it had higher absorptivity for aniline and the adsorption capacity could reach 42.2 mg/g at 45 min and pH = 7. Moreover, the PP-g-(AA-MAH) fibers showed good regeneration performance.

Ion-Imprinted Polypropylene Fibers Fabricated by the Plasma-Mediated Grafting Strategy for Efficient and Selective Adsorption of Cr(VI).

To improve the adsorption selectivity towards hexavalent chromium anion (Cr(VI)), surface Cr(VI)-imprinted polypropylene (PP) fibers were fabricated by the plasma-mediated grafting strategy. Hence, a non-thermal Rradio frequency discharge plasma irradiation followed by a gaseous phase grafting was used to load acrylic acid (AA) onto PP fibers, which was afterwards amidated with triethylenetetramine and subjected to imprinting with a Cr(VI) template. The plasma irradiation conditions, i.e., gas species, output power, pressure, and time, were optimized and then the influence of grafting time, pressure, and temperature on the grafting degree of AA was investigated. Scanning electron microscopy and Fourier transform infrared spectroscopy were used for the characterization of pristine and modified fibers and to confirm the synthesis success. The hydrophilicity of modified fibers was greatly improved compared with pristine PP fibers. The adsorption thermodynamics and kinetics of Cr(VI) were investigated, as well as the elution efficiency and reusability. The prepared imprinted fibers showed superior adsorption selectivity to Cr(VI) compared with non-imprinted fibers. Finally, the stability of the imprinted fibers against the oxidation ability of Cr(VI) is discussed.

Ultrasonic-Assisted Dispersion of ZnO Nanoparticles and Its Inhibition Activity to Trichoderma viride.

The activity inhibition of fungi by ZnO nanoparticles (NPs) has shown huge potential applications in the area of hygienic coatings. However, the inhibition efficiency was limited due to the agglomeration of NPs. To obtain well-dispersed and highly stabilized ZnO nanofluids, ZnO NPs were capped with four kinds of surfactants under ultrasonication. The capping procedure was optimized by varying the dosage of surfactants, the ultrasonic duration, ultrasonic power and temperature. Capped ZnO nanofluids were then used for the inhibition of Trichoderma viride. The influence on the activity of the capping conditions, illumination, ZnO NPs content, humidity and temperature were investigated in details. Results suggest that well-dispersed ZnO NPs were obtained through ultrasonic-assisted functionalization using sodium polyacrylate as a dispersant. Moreover, capped ZnO nanofluids revealed long-term stability at pH above 6. The optimal capping procedure was obtained for a sonication power of 250 W, treatment duration of 40 min, dosage of 0.4% and temperature of 60 °C. Antifungal tests indicated that capped ZnO NPs showed an inhibition ability versus T. viride even in the dark. The antifungal ability of ZnO NPs increased with the increasing ZnO content, and humidity and temperature only affected the growth of fungi. Capped ZnO NPs showed an excellent antifungal performance even in the circumstance that was beneficial for the fungi growth (temperature of 30 °C, humidity of 95%), demonstrating the antimicrobial capability in practical applications.

Bisphenol F Disrupts Thyroid Hormone Signaling and Postembryonic Development in Xenopus laevis.

The safety of bisphenol A (BPA) alternatives has attracted much attention due to their wide use. In this study, we investigated the effects of bisphenol F (BPF), an alternative to BPA, on thyroid hormone (TH) signaling and postembryonic development in vertebrates using T3-induced and spontaneous Xenopus metamorphosis as models. We found that in the T3-induced metamorphosis assay, higher concentrations of BPF (100-10000 nM) antagonized T3-induced TH-response gene transcription and morphological changes including intestinal remodeling in a concentration-dependent manner, whereas 10 nM BPF exerted stimulatory effects on T3-induced integral metamorphosis when inhibited T3-induced TH-response gene transcription, demonstrating TH signaling disrupting effects of BPF. In the spontaneous metamorphosis assay, correspondingly, BPF inhibited development at metamorphic climax (with high endogenous TH levels), but promoted pre- and pro-metamorphic development (with low endogenous TH levels), displaying a developmental stage-dependent manner. Importantly, we observed agonistic actions of BPF on Notch signaling in intestines, showing that BPF disrupts vertebrate development possibly via multi pathways besides TH signaling. Thus, we infer the biphasic concentration-response relationship between BPF exposure and T3-induced metamorphosis could result from the interactions of TH signaling with other signaling pathways such as Notch signaling. Our study highlights the adverse influences of BPF on vertebrate development.

Re-evaluation of thyroid hormone signaling antagonism of tetrabromobisphenol A for validating the T3-induced Xenopus metamorphosis assay.

We developed the T3-induced Xenopus metamorphosis assay, which is supposed to be able to sensitively detect thyroid hormone (TH) signaling disruption of chemicals. The present study aimed to validate the T3-induced Xenopus metamorphosis assay by re-evaluating the TH signaling antagonism of tetrabromobisphenol A (TBBPA), a known TH signaling disruptor. According to the assay we developed, Xenopus tadpoles at stage 52 were exposed to 10-500nmol/L TBBPA in the presence of 1nmol/L T3. After 96hr of exposure, TBBPA in the range of 10-500nmol/L was found to significantly inhibit T3-induced morphological changes of Xenopus tadpoles in a concentration-dependent manner in term of body weight and four morphological endpoints including head area (HA), mouth width (MW), unilateral brain width/brain length (ULBW/BL), and hind-limb length/snout-vent length (HLL/SVL). The results show that these endpoints we developed are sensitive for characterizing the antagonistic effects of TBBPA on T3-induced metamorphosis. Following a 24-hr exposure, we found that TBBPA antagonized expression of T3-induced TH-response genes in the tail, which is consistent with previous findings in the intestine. We propose that the tail can be used as an alternative tissue to the intestine for examining molecular endpoints for evaluating TH signaling disruption. In conclusion, our results demonstrate that the T3-induced Xenopus metamorphosis assay we developed is an ideal in vivo assay for detecting TH signaling disruption.

Reductions of bacterial antibiotic resistance through five biological treatment processes treated municipal wastewater.

Wastewater treatment plants are hot spots for antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs). However, limited studies have been conducted to compare the reductions of ARB and ARGs by various biological treatment processes. The study explored the reductions of heterotrophic bacteria resistant to six groups of antibiotics (vancomycin, gentamicin, erythromycin, cephalexin, tetracycline, and sulfadiazine) and corresponding resistance genes (vanA, aacC1, ereA, ampC, tetA, and sulI) by five bench-scale biological reactors. Results demonstrated that membrane bioreactor (MBR) and sequencing batch reactor (SBR) significantly reduced ARB abundances in the ranges of 2.80∼3.54 log and 2.70∼3.13 log, respectively, followed by activated sludge (AS). Biological filter (BF) and anaerobic (upflow anaerobic sludge blanket, UASB) techniques led to relatively low reductions. In contrast, ARGs were not equally reduced as ARB. AS and SBR also showed significant potentials on ARGs reduction, whilst MBR and UASB could not reduce ARGs effectively. Redundancy analysis implied that the purification of wastewater quality parameters (COD, NH4 (+)-N, and turbidity) performed a positive correlation to ARB and ARGs reductions.

Low concentrations of 17ß-trenbolone induce female-to-male reversal and mortality in the frog Pelophylax nigromaculatus.

Trenbolone, as a growth promoter in animal agriculture, has become an environmental androgen in surface water. Here, we aimed to reveal the effects of 17ß-trenbolone on survival, growth, and gonadal differentiation in the frog Pelophylax nigromaculatus, which is widespread in East Asia and undergoing population decline. P. nigromaculatus tadpoles were exposed to 17ß-trenbolone (0.1, 1, 10 µg/L) from Gosner stage 24/25 to complete metamorphosis. We found that 17ß-trenbolone resulted in significantly high mortality in a concentration-dependent manner, with a decrease in body weight in the high concentration group compared with the solvent control. Based on gross gonadal morphology, no females were observed, instead of about 15% ambiguous sexes and 85% males, in all 17ß-trenbolone treatment groups. Like normal testes, the gonads with sex-ambiguous morphology exhibited testicular histology, showing that the sex-ambiguous gonads were incomplete ovary-to-testis reversals (IOTTRs) with certain ovarian morphological features. In the IOTTRs, the transcriptional levels of ovary-biased genes decreased drastically relative to normal ovaries, and even declined to the levels in normal testes. These observations confirmed that all test concentrations of 17ß-trenbolone resulted in 100% sex reversal, although some sex-reversed testes retained some ovarian characteristics at the morphological level. To our knowledge, this is the first report strongly demonstrating that trenbolone can cause female-to-male reversal in amphibians. Given that the lowest concentration tested is environmentally relevant, our study highlights the risks of trenbolone and other environmental androgens for P. nigromaculatus and other amphibians, in particular the species with high sensitivity of gonadal differentiation to androgenic chemicals.

Molecular characterization and mRNA expression of ribosomal protein L8 in Rana nigromaculata during development and under exposure to hormones.

Like Xenopus laevis, some species of the Rana genus are also used to study endocrine disrupting chemicals (EDCs). Although ribosomal protein L8 (rpl8) is the most-used reference gene for analyzing gene expression by quantitative reverse transcription polymerase chain reaction in Rana, its suitability as the reference gene has never been validated in any species of the Rana genus. We characterized rpl8 cDNA in Rana nigromaculata, a promising native species in East Asia for assaying endocrine disrupting effects. We found that the rpl8 cDNA consisted of 919bp and encoded 257 amino acids, exhibiting high identities of amino acid sequence with known rpl8 in other Rana species. Then, we examined the stability of mRNA expression during development. Compared with elongation factor 1 alpha 1, another common housekeeping gene, neither stage-specific nor tissue-specific expression of the rpl8 gene was found in all tissues examined (brain, liver, intestine, tail, testis and ovary) during R. nigromaculata development. Finally, we investigated rpl8 expression under exposure to hormones. No change in rpl8 mRNA expression was found under exposure to thyroid hormone (T4) and estrogen (estradiol), whereas expression of the corresponding biomarker genes was induced. Our results show that rpl8 is an appropriate reference gene for analyzing gene expression by quantitative reverse transcription polymerase chain reaction for assaying EDCs using R. nigromaculata, and might also provide support for using rpl8 as a reference gene in other Rana species due to the high conservation of rpl8 among the Rana genus.

Molecular characterization and developmental expression patterns of thyroid hormone receptors (TRs) and their responsiveness to TR agonist and antagonist in Rana nigromaculata.

Considering some advantages of Rana nigromaculata as an experimental species, we propose that this species, like Xenopus laevis, could be used to assay thyroid hormone (TH) signaling disrupting actions. To validate the utilizability of R. nigromaculata, we investigated the responsiveness of R. nigromaculata to a TH receptor (TR) agonist (T3) and antagonist (amiodarone) by analyzing expression, based on characterizing TR cDNA and developmental expression patterns. With high levels of identity with the corresponding genes in X. laevis, both TRα and TRß in R. nigromaculata exhibited roughly similar developmental expression patterns to those of X. laevis, in spite of some species-specific differences. Both TRα and TRß expression had greater changes in the liver and intestine than in the tail and brain during metamorphosis. T3 exposure for 2days induced more dramatic increases of TRß expression in stage 27 than in stage 34 tadpoles but not in stage 42 tadpoles, showing that the responsiveness of R. nigromaculata to TH decreased with development and disappeared at the onset of metamorphic climax. Corresponding to greater changes of TRß expression in the liver and intestine than in the tail and brain during metamorphosis, the liver and intestine had higher responsiveness to exogenous T3 than the tail and brain. Amiodarone inhibited T3-induced TRß expression. Our results show that R. nigromaculata can be used as a model species for assaying TH signaling disrupting actions by analyzing TRß expression, and intestine tissues at stage 27 are ideal test materials due to high responsiveness and easy accessibility.

Tetrabromobisphenol A disrupts vertebrate development via thyroid hormone signaling pathway in a developmental stage-dependent manner.

Data concerning effects of tetrabromobisphenol A (TBBPA) on thyroid hormone (TH)-dependent vertebrate development have been limited, although TBBPA has been demonstrated in vitro to disrupt the TH signaling pathway at the transcriptional level. In this study, we investigated the effects of TBBPA on T3-induced and spontaneous Xenopus laevis metamorphosis, which share many similarities with TH-dependent development in higher vertebrates. In a 6-day T3-induced metamorphosis assay using premetamorphic tadpoles, 10-1000 nM TBBPA exhibited inhibitory effects on T3-induced expression of TH-response genes and morphological changes in a concentration-dependent manner, with a weak stimulatory action on tadpole development and TH-response gene expression in the absence of T3 induction. In a spontaneous metamorphosis assay, we further found that TBBPA promoted tadpole development from stage 51 to 56 (pre- and prometamorphic stages) but inhibited metamorphic development from stage 57 to 66 (metamorphic climax). These results strongly show that TBBPA, even at low concentrations, disrupts TH-dependent development in a developmental stage-dependent manner, i.e., TBBPA exhibits an antagonistic activity at the developmental stages when animals have high endogenous TH levels, whereas it acts as an agonist at the developmental stages when animals have low endogenous TH levels. Our study highlights the adverse influences of TBBPA on TH-dependent development in vertebrates.

Environmental (anti-)androgenic chemicals affect germinal vesicle breakdown (GVBD) of Xenopus laevis oocytes in vitro.

Progesterone-induced germinal vesicle breakdown (GVBD) of Xenopus oocytes in vitro was used to study endocrine disrupting activity of chemicals in previous studies. In this study, we investigated for the first time effects of environmental androgens on oocyte maturation and effects of anti-androgens on androgen-induced oocyte maturation, using Xenopus GVBD in vitro. Trenbolone and nandrolone, two environmental androgens, were found to induce Xenopus GVBD at low concentrations. The potential of trenbolone to induce GVBD was approximately 100-fold lower than that of testosterone, while nandrolone had a several-fold lower potential than testosterone. Our findings have aroused new concerns for effects of environmental androgens on amphibian oocyte maturation at environmentally relevant concentrations, and suggested that Xenopus GVBD can be used to test androgenic activity of suspicious environmental androgens. Androgen receptor (AR) antagonist flutamide at 10 µM only exhibited a weakly inhibitory effect on androgen-induced GVBD, while another known AR antagonist vinclozolin had no effect even at high concentrations. The results show that Xenopus GVBD is not sensitive to AR-mediated environmental anti-androgens. In contrast to flutamide and vinclozolin, methoxychlor (a weaker AR antagonist) inhibited dramatically androgen-induced GVBD, suggesting that androgen-induced Xenopus GVBD can be used to study non-AR-mediated effects of chemicals on oocyte maturation.

Effects of perfluorooctanesulfonate and perfluorobutanesulfonate on the growth and sexual development of Xenopus laevis.

Perfluorobutanesulfonate (PFBS), as a substitute for perfluorooctanesulfonate (PFOS), is widespread in the environment and biotic samples as well as PFOS. To investigate effects of PFOS and PFBS on the growth and sexual development of amphibians, we exposed Xenopus laevis tadpoles at a series of concentrations of PFOS and PFBS (0.1; 1; 100; 1,000 µg/l) as well as 17-beta-estradiol (E2, 100 ng/l) and 5 alpha-androstan-17-beta-ol-3-one (DHT, 100 ng/l) from stage 46/47 to 2 months postmetamorphosis. We found that neither PFOS nor PFBS had a significant effect on the survival and growth. However, they caused hepatohistological impairment at higher concentrations (100; 1,000 µg/l). Unlike E2, PFOS at all concentrations did not alter the sex ratio and induce intersex, but caused degeneration of spermatogonia in testes except for the lowest concentration. PFBS had no effect on the sex ratio and gonadal histology. PFOS and PFBS promoted expression of estrogen receptor (ER) and androgen receptor (AR), but not affected aromatase expression in the brain. The increase in expression of ER and AR suggests an increase in the responsiveness to the corresponding sex hormone and potential effects on sexual development. Our results show that PFBS as well as PFOS have adverse effects on hepato-histology and sexual development on X. laevis. Also, PFOS- and PFBS-induced increase in ER and AR expression highlights the need to further study effects of PFOS and PFBS on subsequently gonadal development, sexual dimorphism, and secondary sex characteristics in X. laevis. It is debatable that PFBS is widely used as a substitute of PFOS.

Polybrominated diphenyl ether (PBDE) in blood from children (age 9-12) in Taizhou, China.

Polybrominated diphenyl ethers (PBDEs) as ubiquitous persistent organic pollutants have attracted much attention in recent years. Exposure to PBDEs could induce a high health risk for children. The aim of this study was to investigate the PBDEs exposure of children (9-12 years) from Taizhou, China. Fifty-eight blood samples were collected in one school in a mountainous area in Taizhou. The concentrations of sigma9PBDEs (sum of BDE-28, -47, -99, -100, -153, -154, -183, -197 and -209) ranged from 2.66 to 33.9 ng/g lipid wet (lw) with a median of 7.22 ng/g lw. These concentrations were lower than those of children in USA, but close to European and Asian general population levels. The results showed that children in Taizhou countryside were at a low level of PBDEs exposure. The predominant congener was BDE-209, followed by BDE-28, -47, -197 and -153. High abundance of BDE-209 was consistent with the pollution background of PBDEs in China characterized by high brominated congeners as main pollutants.