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  • 1
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    Preparation of chitosan/MCM-41-PAA nanocomposites and the adsorption behaviour of Hg(II) ions (2018)
    Royal Society
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    Publication Date: 2018-03-29
    Description: A novel functional hybrid mesoporous composite material (CMP) based on chitosan and MCM-41-PAA was reported and its application as an excellent adsorbent for Hg(II) ions was also investigated. Innovatively, MCM-41-PAA was prepared by using diatomite and polyacrylic acid (PAA) with integrated polymer–silica hybrid frameworks, and then CMP was fabricated by introducing MCM-41-PAA to chitosan using glutaraldehyde as a cross-linking agent. The structure and morphology of CMP were characterized by X-ray diffraction, Fourier transform infrared spectra, thermogravimetric analysis, scanning electron microscopy and Brunauer–Emmett–Teller measurements. The results showed that the CMP possessed multifunctional groups such as –OH, –COOH and –NH 2 with large specific surface area. Adsorption behaviour of Hg(II) ions onto CMP was fitted better by the pseudo-second-order kinetic model and the Langmuir model when the initial Hg(II) concentration, pH, adsorption temperature and time were 200 mg l –1 , 4, 298 K and 120 min, respectively, as the optimum conditions. The corresponding maximum adsorption capacity could reach 164 mg g –1 . According to the thermodynamic parameters determined such as free energy, enthalpy and entropy, the adsorption process of Hg(II) ions was spontaneous endothermic adsorption.
    Keywords: chemical physics, environmental chemistry, environmental science
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
    Published by Royal Society
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  • 2
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    Synthesis of cyclic ethers by cyclodehydration of 1,n-diols using heteropoly acids as catalysts (2018)
    Royal Society
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    Publication Date: 2018-09-27
    Description: Heteropoly acids were used as catalysts for cyclodehydration of various 1, n -diols. Cyclodehydration of butane-1,4-diol, pentane-1,5-diol and hexane-1,6-diol catalysed by H 3 PW 12 O 40 gave tetrahydrofuran, tetrahydropyran and oxepane, respectively. Cyclodehydration of diethylene glycol, triethylene glycol, diethylene glycol monomethyl ether and polyethylene glycol 200 catalysed by H 3 PW 12 O 40 gave 1,4-dioxane. In particular, cyclodehydration of hexane-1,6-diol gave an excellent yield of oxepane (80%). The selectivity exhibited by the H 3 PW 12 O 40 catalyst was even better than that exhibited by other reported catalyst systems for similar cyclodehydration reactions.
    Keywords: organic chemistry, synthetic chemistry, green chemistry
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
    Published by Royal Society
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  • 3
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    Sexual phenotype drives variation in endocrine responses to social challenge in a quasi-clonal animal (2018)
    Royal Society
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    Publication Date: 2018-04-05
    Description: In many species, males tend to behave more aggressively than females and female aggression often occurs during particular life stages such as maternal defence of offspring. Though many studies have revealed differences in aggression between the sexes, few studies have compared the sexes in terms of their neuroendocrine responses to contest experience. We investigated sex differences in the endocrine response to social challenge using mangrove rivulus fish, Kryptolebias marmoratus . In this species, sex is determined environmentally, allowing us to produce males and hermaphrodites with identical genotypes. We hypothesized that males would show elevated androgen levels (testosterone and 11-ketotestosterone) following social challenge but that hermaphrodite responses might be constrained by having to maintain both testicular and ovarian tissue. To test this hypothesis, we staged fights between males and between hermaphrodites, and then compared contest behaviour and hormone responses between the sexes. Hermaphrodites had significantly higher oestradiol but lower 11-ketotestosterone than males before contests. Males took longer to initiate contests but tended to fight more aggressively and sustain longer fights than hermaphrodites. Males showed a dramatic post-fight increase in 11-ketotestosterone but hermaphrodites did not. Thus, despite being genetically identical, males and hermaphrodites exhibit dramatically different fighting strategies and endocrine responses to contests.
    Keywords: behaviour, physiology, ecology
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
    Published by Royal Society
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  • 4
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    Large-scale fabrication of porous YBO3 hollow microspheres with tunable photoluminescence (2018)
    Royal Society
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    Publication Date: 2018-04-12
    Description: Hollow lanthanide-doped compounds are some of the most popular materials for high-performance luminescent devices. However, it is challenging to find an approach that can fabricate large-scale and well-crystallized lanthanide-doped hollow structures and that is facile, efficient and of low cost. In this study, YBO 3 : Eu 3+ /Tb 3+ hollow microspheres were fabricated by using a novel multi-step transformation synthetic route for the first time with polystyrene spheres as the template, followed by the combination of a facile homogeneous precipitation method, an ion-exchange process and a calcination process. The results show that the as-obtained YBO 3 : Eu 3+ /Tb 3+ hollow spheres have a uniform morphology with an average diameter of 1.65 µm and shell thickness of about 160 nm. When used as luminescent materials, the emission colours of YBO 3 : Eu 3+ /Tb 3+ samples can be tuned from red, through orange, yellow and green-yellow, to green by simply adjusting the relative doping concentrations of the activator ions under the excitation of ultraviolet light, which might have potential applications in fields such as light display systems and optoelectronic devices.
    Keywords: inorganic chemistry, materials science, nanotechnology
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
    Published by Royal Society
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  • 5
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    Environmentally friendly and breathable wet-laid hydroentangled nonwovens for personal hygiene care with excellent water absorbency and flushability (2018)
    Royal Society
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    Publication Date: 2018-04-19
    Description: Developing wet-laid papers with a good wet strength remains a longstanding challenge in the papermaking industry. In this study, hydroentanglement, a mechanical bonding technique is developed to consolidate the wet-laid fibre web. The results indicate that wet tensile strength, ductile stretching property, softness, air permeability and water absorbency of the wet-laid fibre web are significantly improved by hydroentanglement. In addition, the abrasion test shows that the dusting off rate of wet-laid fibre web can be effectively reduced through hydroentanglement. Moreover, the disintegration experiment proves that wet-laid hydroentangled nonwovens could be easily dispersed when compared with conventional carded hydroentangled nonwovens. Therefore, the new wet-laid hydroentangled nonwovens can maintain excellent performance in a wet state, showing a great potential for personal hygiene applications.
    Keywords: materials science
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
    Published by Royal Society
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  • 6
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    Effective harvesting of microalgae by coagulation-flotation (2017)
    Royal Society
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    Publication Date: 2017-11-16
    Description: This study developed a coagulation–flotation process for microalgae Chlorella sp. XJ-445 harvesting, which was composed of algal surface modification by combined use of Al 3+ and cetyltrimethylammonium bromide (CTAB) and followed dispersed bubble flotation. Dissolved organic matter (DOM) in the medium was firstly characterized and mainly consisted of hydrophilic low molecular weight molecules. The dosage of collector (CTAB) and coagulant (Al 3+ ) were optimized, and with the pretreatment of 40 mg Al 3+ and 60 mg CTAB per 1 g dry biomass without pH adjustment, a maximum flotation recovery efficiency of 98.73% can be achieved with the presence of DOM. Algal cells characterization results showed that the combined use of CTAB and Al 3+ largely enhanced the algal floc size, and exhibited higher degree of hydrophobicity, which favoured the flotation, and can be interpreted by DLVO (Derjaguin, Landau, Verwey and Overbeek) modelling. A benefit in fatty acid conversion was further found with the optimized coagulation–flotation process. It was suggested that this coagulation based flotation is a promising strategy for high-efficiency harvesting of microalgae.
    Keywords: biotechnology
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
    Published by Royal Society
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  • 7
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    The adsorption features between insecticidal crystal protein and nano-Mg(OH)2 (2017)
    Royal Society
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    Publication Date: 2017-12-07
    Description: Nano-Mg(OH) 2 , with low biological toxicity, is an ideal nano-carrier for insecticidal protein to improve the bioactivity. In this work, the adsorption features of insecticidal protein by nano-Mg(OH) 2 have been studied. The adsorption capacity could reach as high as 136 mg g –1 , and the adsorption isotherm had been fitted with Langmuir and Freundlich models. Moreover, the adsorption kinetics followed a pseudo-first or -second order rate model, and the adsorption was spontaneous and an exothermic process. However, high temperatures are not suitable for adsorption, which implies that the temperature would be a critical factor during the adsorption process. In addition, FT-IR confirmed that the protein was adsorbed on the nano-Mg(OH) 2 , zeta potential analysis suggested that insecticidal protein was loaded onto the nano-Mg(OH) 2 not by electrostatic adsorption but maybe by intermolecular forces, and circular dichroism spectroscopy of Cry11Aa protein before and after loading with nano-Mg(OH) 2 was changed. The study applied the adsorption information between Cry11Aa and nano-Mg(OH) 2 , which would be useful in the practical application of nano-Mg(OH) 2 as a nano-carrier.
    Keywords: behaviour, biotechnology, chemical biology
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
    Published by Royal Society
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  • 8
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    Semisynthesis and insecticidal activity of some novel fraxinellone-based thioethers containing 1,3,4-oxadiazole moiety (2017)
    Royal Society
    Details
    Publication Date: 2017-12-14
    Description: Two series of novel fraxinellone-based thioethers containing 1,3,4-oxadiazole moiety were prepared as insecticidal agents against the oriental armyworm, Mythimna separata Walker. The structural assignment was based on the spectroscopic and X-ray analysis data. Among all the target compounds, compounds 4b , 4k , 5b , 5j and 5k exhibited more potent insecticidal activity with final mortality rates (FMRs) of more than 65%, especially 4k with the FMR of 75.9%, when compared with toosendanin. Some interesting results of structure–activity relationships are also discussed.
    Keywords: organic chemistry, synthetic chemistry
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
    Published by Royal Society
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  • 9
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    Facile synthesis of NiCo2S4/CNTs nanocomposites for high-performance supercapacitors (2018)
    Royal Society
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    Publication Date: 2018-09-13
    Description: Herein, porous NiCo 2 S 4 /CNTs nanocomposites were synthesized via a simple hydrothermal method followed by the sulphurization process using different sulfide sources. By comparing two different sulfur sources, the samples using thioacetamide as sulfide source delivered more remarkable electrochemical performance with a high specific capacitance of 1765 F g –1 at 1 A g –1 and an admirable cycling stability with capacitance retention of 71.7% at a high current density of 10 A g –1 after 5000 cycles in 2 M KOH aqueous electrolyte. Furthermore, an asymmetric supercapacitor (ASC) device was successfully fabricated with the NiCo 2 S 4 /CNTs electrode as the positive electrode and graphene as the negative electrode. The device provided a maximum energy density of 29.44 W h kg –1 at a power density of 812 W kg –1 . Even at a high power density of 8006 W kg –1 , the energy density still reaches 16.68 W h kg –1 . Moreover, the ASC presents 89.8% specific capacitance retention after 5000 cycles at 5 A g –1 . These results reveal its great potential for supercapacitors in electrochemical energy storage field.
    Keywords: nanotechnology
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
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  • 10
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    Identification and characterization of circular RNAs in Qinchuan cattle testis (2018)
    Royal Society
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    Publication Date: 2018-07-26
    Description: Circular RNA (circRNA) is a new class of non-coding RNA that has recently attracted researchers' interest. Studies have demonstrated that circRNA can function as microRNA sponges or competing endogenous RNAs. Although circRNA has been explored in some species and tissues, the genetic basis of testis development and spermatogenesis in cattle remains unknown. We performed ribo-depleted total RNA-Seq to detect circRNA expression profiles of neonatal (one week old) and adult (4 years old) Qinchuan cattle testes. We obtained 91 112 596 and 80 485 868 clean reads and detected 21 753 circRNAs. A total of 4248 circRNAs were significantly differentially expressed between neonatal and adult cattle testes. Among these circRNAs, 2225 were upregulated, and 2023 were downregulated in adult cattle testis. Genomic feature, length distribution and other characteristics of the circRNAs in cattle testis were studied. Moreover, Gene Ontology and KEGG pathway analyses were performed for source genes of circRNAs. These source genes were mainly involved in tight junction, adherens junction, TGFβ signalling pathway and reproduction, such as PIWIL1, DPY19L2, SLC26A8, IFT81, SMC1B, IQCG and TTLL5 . CircRNA expression patterns were validated by RT-qPCR. Our discoveries provide a solid foundation for the identification and characterization of key circRNAs involved in testis development or spermatogenesis.
    Keywords: genetics, genomics
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
    Published by Royal Society
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