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In this paper, we reported the preparation of ZnO/ZnS core/shell nanocomposites by sulfidation of ZnO nanostructures via a simple hydrothermal method. The precursors of bare ZnO nanoparticles and ZnO nanorods were synthesized by a surfactant-assisted hydrothermal growth. The structural, morphological, and element compositional analysis of bare ZnO nanostructures and ZnO/ZnS core/shell nanocomposites were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, and transmission electron microscopy techniques. The XRD results indicated that the phase of bare ZnO nanoparticles and ZnO nanorods was wurtzite structure, and the phase of coated ZnS nanoparticles on the surface of bare ZnO nanostructures was sphalerite structure with the size of about 8 nm. Photoluminescence measurement was carried out, and the PL spectra of ZnO/ZnS core/shell nanocomposites revealed an enhanced UV emission and a passivated orange emission compared to that of bare ZnO nanostructures. In addition, the growth mechanism of ZnO/ZnS core/shell nanostructures through hydrothermal method was preliminarily discussed. [ABSTRACT FROM AUTHOR]

Several semiconductor nanomaterial devices are increasingly being applied in a variety of fields, especially in the treating of environmental pollutants. We have fabricated (MnO@TNTAs):Mn2+ with sandwich-like nanostructures composed of TiO2 nanotube arrays (TNTAs), Mn-doped TNTAs and MnO. The experimental procedure was a two-step synthesis: first, using anodic oxidation methods and then hydrothermal methods. We carried out many characterizations of the “sandwiches“ in the nanoscale. From the field emission scanning electron microscopy images we found nanofibers lying on the highly-ordered nanotube arrays. The diameter of the nanotubes was about 50 nm but the size of the nanofibers varied. Energy dispersive spectroscopy demonstrated that the nanofibers contained a manganese element and x-ray diffraction patterns showed the peak of the manganosite phase. From ultraviolet-visible light spectra, it was found that the nanostructures had strong absorption activities under both ultraviolet and visible light radiation, while pure TNTAs had absorption only under ultraviolet light. The photodegradation experiments proved that the sandwich-like nanostructures had an excellent photocatalytic activity (92.5% after 240 min), which was a great improvement compared with pure TNTAs. In this way, the structures as a device at the nanoscale have a huge potential in controlling environmental pollution. [ABSTRACT FROM AUTHOR]

Nanochannels were attractive nanostructures due to their special small sizes and biomimetic functions. Here we reported a novel hybrid nanochannel, which combined with TiO2 nanostructures and anodic aluminum oxide (AAO) membrane. We used a facile solution-dipping method to make TiO2 nanostructures assemble in the nanochannnels of AAO membrane. The morphologies of nanochannels were monitored by field emission scanning electron microscopy and the micro-regional compositions were characterized by energy dispersive spectrometer. Optical information of the nanochannels were recorded by ultraviolet–Visible spectrophotometer, and the ionic current through nanochannels was recorded by an electrochemical workstation. From the results, the TiO2 nanostructures were well-anchored on the walls of nanochannels and the size of nanostructures was uniform. The optical properties and ionic current of hybrid nanochannels would change when the conditions of dipping method changed. For this, this nanochannel had huge potential in the field of photovoltaic conversion, ionic rectifier and biosensor. [ABSTRACT FROM AUTHOR]

Our efforts to introduce defects in futile by conventional mechanical grinding as used for TEM study did not produce any defects or twinning. Experimental SAED patterns of rutile with intercalated [alpha]-Pb[O.sub.2]-type Ti[O.sub.2] lamellae are consistent with those expected from calculated patterns. The values and precision of lattice parameters of [alpha]-Pb[O.sub.2]-type Ti[O.sub.2] derived from such SAED patterns are also consistent with crystal data from X-ray diffraction studies. Keywords: Ti[O.sub.2], high-resolution transmission electron microscope, Dabie mountains, UHP metamorphism

A series of SO/ x wt% Ce-Al-Fe-O solid acid catalysts were prepared by the sol-gel method. Their catalytic performances for the synthesis of n-butyl acetate from acetic acid and n-butanol were investigated. The catalytic properties and crystalline phases of SO/ x wt% Ce-Al-Fe-O solid acid catalysts were characterized by XRD, IR, TG/DSC and SEM techniques. Experimental results showed that SO/10 wt% Ce-Al-Fe-O solid acid catalyst exhibited the highest catalytic activity with 99.90 % esterification efficiency of acetic acid. Moreover, the SO/10 wt% Ce-Al-Fe-O solid acid catalyst showed excellent stability with no obvious change in catalytic activity even after being used repeatedly for eight times. [ABSTRACT FROM AUTHOR]

New types of SO/Al- x wt%Ce-Zn-O solid acid catalysts were prepared by the sol-gel method. Their catalytic performances for the synthesis of n-butyl acetate from acetic acid and n-butanol were investigated. The characterization of prepared catalysts was performed using XRD, IR, TG-DSC and SEM. The experimental results showed that the SO/Al-2.5 wt%Ce-Zn-O solid acid catalyst exhibited an optimal esterification performance with 98.71% esterification efficiency under the optimum synthesis conditions. Moreover, the SO/Al-2.5 wt%Ce-Zn-O solid acid catalyst retained its high activity with above 95% esterification efficiency after being used repeatedly for seven times, which indicated that the SO/Al-2.5 wt%Ce-Zn-O solid acid catalyst had excellent stability. [ABSTRACT FROM AUTHOR]

The crystal structures and polytypism of bastnaesite-(Ce) (CeCO3F, B layer) and synchysite-(Ce) (CeCO3F·CaCO3, S layer) mineral series are very complicated in Sichuan Province, Southwest China. Four new polytypes: 6R, 2H2, 4H and 12H of the mixed-layer member CaCe3(CO3)4F3 (B2S) of this series were discovered by X-ray diffraction analyses and high resolution transmission electron microscopy, structural symmetry, cell and subcell parameters, possible space group, and structural stacking mode (dededgfg/…). They reveal that the mixed-layer member B2S is formed by the ordered stacking of two structural unit layers of bastnaesite-(Ce) (B layer) and one unit layer of synchysite-(Ce) (S layer) along the c direction. The forming of the new polytypes may depend on distributions and the periodical variation of orientation of the [CO3] groups between the unit layers of B2S. We have observed the {000l} microtwin of the 6R polytype and the syntactic intergrowths among the different polytypes formed by stacking faults in B2S. [Copyright &y& Elsevier]

We present the results of high-resolution transmission electron microscope (HRTEM) studies on jadeite crystals of jadeite quartzite from the Dabie ultra-high-pressure (UHP) metamorphic terrane, China. Although jadeite is known to have only C2/c crystal structure, [100], [110], [112], [010] diffraction patterns and HRTEM images reveal C2/c and P21/n structures in 500 nm microdomains of single jadeite crystals, that we recognized in all the above four orientations. The cell parameters of C2/c crystal structure correspond to those of jadeite, whereas the cell parameters of P21/n structure are equivalent to those of omphacite. The presence of the P21/n structure shows that jadeite partially changed into omphacite on a nano-scale during retrograde metamorphism and that this reaction failed to reach equilibrium. It suggests uplift of the host rock during exhumation accompanied by complex non-equilibrium retrogressive process in the jadeite, with significant implications for the derivation of P–T paths and tectonic interpretation of the Dabie UHP metamorphic terrane. [Copyright &y& Elsevier]

Introduction: A combination of zidovudine (AZT), lamivudine (3TC) and lopinavir/ritonavir (LPV/r) is one of the most effective drugs for preventing mother‐to‐child transmission (PMTCT) of HIV. However, limited information is available regarding its systemic toxicity. This study aimed to investigate its potential toxicity. Method: An acute oral toxicity test was conducted to assess the potential acute toxicity of AZT + 3TC + LPV/r. Bacterial reverse mutation, mammalian erythrocyte micronucleus and mouse spermatogonia chromosomal aberration tests were conducted to assess its potential genotoxicity. A 28‐day feeding test was conducted to assess the potential subacute toxicity. Results: In mice, the LD50 of the AZT + 3TC + LPV/r mixture was greater than 2000 mg/kg body weight (BW). The rate of micronucleated polychromatic erythrocytes (PCEs) increased in a dose‐dependent manner in mice (P < 0.01). After treatment with AZT + 3TC + LPV/r for 28 days, the BW gain of male and female rats in the high‐dose group was lower than that in the control group (P < 0.05); the relative weights of the liver, kidney, spleen and brain increased (P < 0.05); and pathological abnormalities appeared in the thyroid and spleen of male and female rats in the high‐dose group. The haemoglobin (HGB) and red blood cells (RBCs) count in male and female rats decreased, but the white blood cells (WBCs) and lymphocyte apoptosis rates in male and female rats in the high‐dose group increased (P < 0.05). The total protein, albumin, cholesterol and blood glucose levels of male and female rats in the high‐dose group were significantly decreased (P < 0.05). The alanine aminotransferase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), creatinine (Cr) and blood urea nitrogen (BUN) levels of male and female rats in the medium‐ and high‐dose groups increased significantly (P < 0.05). Conclusion: The results suggest that AZT + 3TC + LPV/r may exhibit genotoxicity and subacute toxicity under experimental conditions. [ABSTRACT FROM AUTHOR]

As an emerging class of organic contaminants, polyhalogenated carbazoles (PHCZs) have been increasingly detected all over the world since 1980s. Due to the environmental persistence, bioaccumulation, and dioxin-like toxicity, PHCZs have aroused widespread concerns in recent years. However, efficient approach for the degradation of PHCZs is quite limited so far. Therefore, in this study, an advanced oxidation process (AOP), sulfidated zero-valent iron/peroxymonosulfate (S-ZVI/PMS) system was used to degrade 3-chlorocarbazole (3-CCZ), which is one of the mostly detected PHCZs congeners. The degradation of 3-CCZ was systematically studied under different conditions by varying the molar ratio of S/Fe, the dosage of S-ZVI or PMS, pH and temperature. The results indicated that S-ZVI/PMS was an effective strategy for PHCZs treatment. The 20-min degradation efficiency of 3-CZZ was up to 96.6% with the pseudo-first-order rate constant of 0.168 min−1 under the conditions of 5 mg/L 3-CZZ, 0.3 g/L S-ZVI (S/Fe = 0.2), 1.0 mM PMS, pH 5.8 and 25 °C. HCO 3 −, Cl− and humic acid (HA) showed inhibitory effects to different degrees. Results of the electron paramagnetic resonance (EPR) and scavenging experiments clarified the dominant role of •OH, followed by 1O 2 and SO 4 •─. The product analysis and DFT calculation revealed three degradation pathways of 3-CCZ, namely hydroxylation, dechlorination and C–N bond cleavage, which largely alleviated the toxicity of the parent compound. This study showed the effectiveness of S-ZVI/PMS system in PHCZs treatment and provided a comprehensive investigation on the degradation behaviors of PHCZs in AOPs. [Display omitted] • S-ZVI/PMS system could effectively degrade 3-CCZ. • OH was the dominant reactive species followed by 1O 2 and SO 4 •─. • Hydroxylation, dechlorination and C–N bond cleavage were initial degradation pathways. • The toxicities of the degradation products were greatly alleviated. [ABSTRACT FROM AUTHOR]

Background: The widespread use of antiretroviral therapy (ART) has resulted in the development of transmitted drug resistance (TDR), which reduces ART efficacy. We explored TDR prevalence and its associated risk factors in newly diagnosed individuals in Guangxi.Methods: We enrolled 1324 participants who were newly diagnosed with HIV-1 and had not received ART at voluntary counselling and testing centres (VCT) in Guangxi, China, who had not received ART. Phylogenetic relationship, transmission cluster, and genotypic drug resistance analyses were performed using HIV-1 pol sequences. We analysed the association of demographic and virological factors with TDR.Results: In total, 1151 sequences were sequenced successfully, of which 83 (7.21%) showed evidence of TDR. Multivariate logistic regression analysis revealed that there was significant difference between the prevalence of TDR and unmarried status (adjusted odds ratio (aOR) = 2.41, 95% CI: 1.23-4.71), and CRF08_BC subtype (aOR = 2.03, 95% CI: 1.13-3.64). Most cases of TDR were related to resistance to non-nucleoside reverse transcriptase inhibitors (4.87%) and V179E was the most common mutation detected. We identified a total of 119 HIV transmission clusters (n = 585, 50.8%), of which 18 (15.1%) clusters showed evidence of TDR (36, 41.86%). Three clusters were identified that included drug-resistant individuals having a transmission relationship with each other. The following parameters were associated with TDR transmission risk: Unmarried status, educational level of junior high school or below, and CRF08_BC subtype may be a risk of the transmission of TDR.Conclusions: Our findings indicated that moderate TDR prevalence and highlighted the importance of continuous TDR monitoring and designing of strategies for TDR mitigation. [ABSTRACT FROM AUTHOR]

The prevalence of HIV-1 in Guangxi is very high, and the rate of HIV-1 infection among men who have sex with men (MSM) has been increasing. Therefore, it is necessary to explore the patterns and risk factors of HIV transmission in Guangxi. For this purpose, individuals diagnosed with HIV-1 during 2013–2018 in Guangxi were recruited. Phylogenetic relationship, transmission clusters, and genotypic drug resistance analyses were performed based on HIV-1 pol sequences. Related factors were analysed to assess for their association with HIV-1 transmission. CRF07_BC (50.4%) and CRF01_AE (33.4%) were found to be the predominant subtypes. The analysed 1633 sequences (50.15%, Guangxi; 49.85%, other provinces) were segregated into 80 clusters (size per cluster, 2–704). We found that 75.3% of the individuals were in three clusters (size ˃ 100), and 73.8% were high-risk spreaders (links ≥ 4). Infection time, marital status, and subtype were significantly associated with HIV-1 transmission. Additionally, 80.2% of recent infections were linked to long-term infections, and 46.2% were linked to other provinces. A low level of transmitted drug resistance was detected (4.8%). Our findings indicated superclusters and high-risk HIV-1 spreaders among the MSM in Guangxi. Effective strategies blocking the route of transmission should be developed. [ABSTRACT FROM AUTHOR]

Abstract: Sheet-like ZnO with regular hexagon shape and uniform diameter has been successfully synthesized through a two-step method without any metal catalyst. First, the sheet-like ZnO precursor was synthesized in a weak alkaline carbamide environment with stirring in a constant temperature water-bath by the homogeneous precipitation method, then sheet-like ZnO was obtained by calcining at 600°C for 2h. The structures and optical properties of sheet-like ZnO have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), photoluminescence (PL) and UV–vis-NIR spectrophotometer. The results reveal that the product is highly crystalline with hexagonal wurtzite phase and has appearance of hexagon at (0001) plane. The HRTEM images confirm that the individual sheet-like ZnO is single crystal. The PL spectrum exhibits a narrow ultraviolet emission at 397nm and a broad visible emission centering at 502nm. The band gap of sheet-like ZnO is about 3.15eV. [Copyright &y& Elsevier]

Graphical abstract An eco-friendly raw kaolinite was used as a novel support to synthesize a highly efficient S/ZA-Kao macroporous solid acid catalyst for typical esterification reactions of oleic acid with methanol and acetic acid with n -butanol in the synthesis of green biofuels. Highlights • A raw kaolinite-supported SO 4 2−/ZnAl 2 O 4 macroporous solid acid was synthesized. • The dispersion, textural and properties of catalysts can be adjusted to optimum. • Biodiesel produced via oleic acid esterification with the conversion of 70.1%. • Bio-oils upgraded via acetic acid esterification with the conversion of 98.2%. • Improved reusability was showed in acetic acid and oleic acid esterification. Abstract A series of raw kaolinite-supported SO 4 2−/ZnAl 2 O 4 (S/ZA-Kao) macroporous solid acid catalysts were synthesized and applied in esterification of both oleic acid with methanol and acetic acid with n -butanol for the biofuels synthesis. The structures and acidic properties of S/ZA-Kao catalysts were characterized by means of XRD, FE-SEM, EDS, BET, FT-IR (direct and NH 3 adsorbed), NH 3 -TPD, TG and XPS. The results indicated the mass ratio of ZnAl 2 O 4 /kaolinite played a significant role in adjusting the active components dispersion, textural and acidic properties. The optimal S/ZA-Kao(6:4) catalysts performed the macroporous structure and the high dispersion of active components, which might be the essential reason for its improved acid sites and reduced limitation of mass transfer. As a result, the macroporous solid acid exhibited superior conversion of 98.2% in acetic acid esterification and 70.1% in oleic acid esterification. The kinetic study demonstrated that the relatively lower values of activation energy over the S/ZA-Kao(6:4) macroporous solid acid, further confirming that the macroporous solid acid was highly efficient for the biofuel synthesis via esterification. Moreover, the further investigation indicated the catalytic activities were closely related to the ratio of Brönsted acid sites on catalysts. Besides, S/ZA-Kao(6:4) macroporous solid acid particularly displayed excellent reusability, which was due to its structural stability and high dispersion of active components. [ABSTRACT FROM AUTHOR]