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Ultrathin MnO2 hollow nanoballoons (UMHNBs) have a large ratio of interfacial to total atoms, corresponding to expected improved performance. However, their synthesis is a challenge due to difficulty in controlling the concentration of the unit cells. Herein, we describe a strategy to synthesize dry intact UMHNBs through a one-step synthesis by inflating MnO2 (reduced from KMnO4) with CO2 (oxidized from single-layer graphene oxide nanosheets) followed by instant freeze-drying. UMHNBs are 30-500 nm in diameter with a shell thickness of 3.7 nm, packing with laminar [MnO6] unit cells in the form of δ-MnO2. UMHNBs show efficient catalytic activity for decomposing the organic dye methylene blue (MB), 15 times the biggest reported value, and have long-term catalytic efficacy and durability. The described strategy in this paper makes use of graphene nanosheets to assemble durable ultrathin hollow nanoballoons.

A series of BiOBr nanosheets was hydrothermally synthesized through pH adjustment of precursor suspensions. X-ray diffraction, X-ray photoelectron spectroscopy, electronic microscopy and UV–vis diffuse reflectance spectroscopy analyses indicate that these nanosheets possess similar crystallinity, surficial composition, structures, band gaps and highly exposed (0 1 0) facets, but different lateral sizes and thicknesses. The visible-light photoactivity of these nanosheets in photodegradation of salicylic acid increases with reduced nanosheet thickness. An inversely linear relationship was obtained between the pseudo-first-order rate constant (k) and the nanosheet thickness. The photoactivity enhancement of the samples with reduced nanosheet thickness is ascribed to the decreasing recombination efficiency of photogenerated charge carriers. This study indicates that the photoactivity of the BiOBr nanosheets with dominant exposed (0 1 0) facets decisively depend on the nanosheet thickness, rather than the percentage of exposed active facets ((0 0 1) facets), which may be universal for other two-dimensional photocatalysts.

Tuning the porosity of NGAs by tailoring the size of GONSs results in the pore-richest NGA with the best mechanical stability and electrocatalytic biosensing activity by using the smallest sonicated GONSs with DA as precursors, where DA favours high N content and 3D crosslinking capability.

Bismuth tungstate (Bi2WO6) nanosheets with dominant exposed (010) facets and various thicknesses (H) and lateral sizes were hydrothermally synthesized via pH adjustment of precursor suspensions. As the pH increases from

A poison-resistant and highly catalytically active Pt(111) lattice on ultrathin Pt nanoplates (Pt(111)NPTs) with a large ratio (28%) of surface active to sum Pt atoms is obtained with a dense small pore N-atom doped aerogel (NGA) featuring a large specific surface area and high N content in the graphene skeleton.

High efficiency is one of the important goals of public procurement (PP); however, research on PP efficiency is still not sufficient, especially in the context of developing countries. With a focus on the purchasing phase, this study measures three aspects of procurement efficiency of public authorities: price, time and intellectual efficiency. The relevant factors of these three aspects are explored and examined. 838 PP contracts in Chengdu city, China were collected in the first half of 2018 using a web crawler programme. Regression method is used to analyse the data. This study finds that the price efficiency of PP is negatively associated with the implementation of green public procurement (GPP) but is positively associated with the evaluation method (the weight of bidding price during evaluation) and the number of bidders. Time efficiency is negatively associated with GPP implementation. Intellectual efficiency is negatively associated with the size of the procurement. This study accomplishes the following: I. extends research to a still relatively unexplored context: developing countries; II. adds to the studies on public procurement efficiency; and III. investigates the influence of GPP implementation on PP efficiency in a developing country.

Manganese oxide nanopyramids (MONPMs) with enriched oxygen vacancies (OVs) are vertically grown on nitrogen doped carbon (NC) microlaminate arrays with narrow spacing, yielding a high performance for the oxygen reduction reaction (ORR).

Microhydrangeas with a high ratio of low valence manganese oxide (HRLV-MOMs) with MnO, Mn2O3 and γ-MnO2 percentages of 49.2%, 32.3% and 18.5%, respectively, are synthesized in a one-step hydrothermal stirring method and allow extremely fast catalytic degradation of organic dyes due to the substantial number of directly produced hydroxyl (˙OH) and superoxide anion (O2˙-) radicals.

Recent advances in Cross-Technology Communication (CTC) enable the coexistence and collaboration among heterogeneous wireless devices operating in the same ISM band (e.g., Wi-Fi, ZigBee, and Bluetooth in 2.4 GHz). However, state-of-the-art CTC schemes are vulnerable to spoofing attacks since there is no practice authentication mechanism yet. This paper proposes a scheme to enable the spoofing attack detection for CTC in heterogeneous wireless networks by using physical layer information. First, we propose a model to detect ZigBee packets and measure the corresponding Received Signal Strength (RSS) on Wi-Fi devices. Then, we design a collaborative mechanism between Wi-Fi and ZigBee devices to detect the spoofing attack. Finally, we implement and evaluate our methods through experiments on commercial off-the- shelf (COTS) Wi-Fi and ZigBee devices. Our results show that it is possible to measure the RSS of ZigBee packets on Wi-Fi device and detect spoofing attack with both a high detection rate and a low false positive rate in heterogeneous wireless networks.

Magnetic composites consisting of magnetite (Fe3O4), graphene oxide (GO), and Mg3Al-OH layered double hydroxide (LDH), denoted as MGL composites, with varying GO contents (RGO) were synthesized by a mechano-hydrothermal (MHT) route using Fe3O4, Mg(OH)2, and Al(OH)3 as the inorganic starting materials. The application of the synthesized MGLs for removing the heavy-metal Pb(II) and the hydrophobic organic pesticide 2,4-dichlorophenoxyacetic acid (2,4-D) from aqueous solutions was investigated. Chemical bonding among the GO, Fe3O4, and LDH components was observed in the MGLs. The MGL composites showed good water-dispersity, strong magnetic response, and high sorption capacities and removal efficiencies for both Pb(II) and 2,4-D pollutants. The sorption capacities of the MGL for the pollutants significantly increased with an increase in RGO. Increasing pH could increase the removal efficiency for Pb(II) but decrease that for 2,4-D. The MGLs showed more affinity for Pb(II) than for 2,4-D in the competitive sorption. In addition, the MGLs could remain almost constant removal efficiency for the pollutants after reuse over six cycles, indicating their potential use as sorbents in wastewater treatment. Furthermore, a Cs effect was observed in the sorption equilibriums, which could be described using the Langmuir-SCA and Freundlich-SCA isotherms. The removal mechanisms of the MGL for Pb(II) and 2,4-D were discussed. The MHT method provided a simple and environmentally friendly route for synthesizing GO-LDH composite materials.

As the interfacial structure and bonding strength play an important role in determining the mechanical performance of carbon nanotube reinforced metal matrix composite, investigating the interfacial mechanical properties of surface modified carbon nanotube reinforced metal matrix composite becomes one of the key factors for the improvement. The mechanical behaviors of nickel-coated single-walled carbon nanotube reinforced magnesium matrix composites were investigated using molecular dynamics simulation method. The results show that the Young's modulus of the nickel-coated single-walled carbon nanotube/Mg composite is obviously larger than that of the uncoated single-walled carbon nanotube/Mg composite. The results also show that the interfacial bonding of single-walled carbon nanotube/Mg composite can be drastically increased by addition of nickel coating to improve the wettability of the nanotube surface and Mg matrix. Furthermore, the influences of nickel coating number on the interfacial bonding characteristics of single-walled carbon nanotube/Mg composites also were studied. For three types of nickel coating number, i.e. without nickel coating, with one layer of nickel and two layers of nickel, the final pullout interfacial bonding strength of the nickel-coated single-walled carbon nanotube from Mg matrix about are 3.9 and 11.9 times larger, respectively, than that of the uncoated single-walled carbon nanotube. The simulation results have proved that such interfaces can effectively transfer load between the nanotube and magnesium matrix in the carbon nanotube/Mg composite, and this will provide the theoretical and experimental basis for the interface mechanics design of the carbon nanotube reinforced composites.

Inapparent avian exposure was suspected for the sporadic infection of avian influenza A(H7N9) occurring in China. This type of exposure is usually unnoticed and difficult to model and measure. Infected poultry with avian influenza H7N9 virus typically remains asymptomatic, which may facilitate infection through inapparent poultry/bird exposure, especially in a country with widespread practice of backyard poultry. The present study proposed a novel approach that integrated ecological and case-control methods to quantify the risk of inapparent avian exposure on human H7N9 infection. Significant associations of the infection with chicken and goose densities, but not with duck density, were identified after adjusting for spatial clustering effects of the H7N9 cases across multiple geographic scales of neighborhood, community, district and city levels. These exposure risks varied geographically in association with proximity to rivers and lakes that were also proxies for inapparent exposure to avian-related environment. Males, elderly people, and farmers were high-risk subgroups for the virus infection. These findings enable health officials to target educational programs and awareness training in specific locations to reduce the risks of inapparent exposure.

Heterojunctions of graphitic carbon nitride (g-C3N4) and Bi2MoO6 were solvothermally synthesized and characterized by X-ray diffraction, Fourier transform-infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy (TEM) and high resolution TEM. The photocatalytic degradation activity of the g-C3N4/Bi2MoO6 composites for Rhodamine B was examined under visible light irradiation. The heterojunction composites exhibited higher photocatalytic activity than pure g-C3N4 or Bi2MoO6. The photocatalytic activity of the composites increased then decreased with increasing Bi2MoO6 content. The g-C3N4/Bi2MoO6 heterojunction with a Bi2MoO6 content of 16.1 wt.% exhibited the highest photocatalytic activity, and its photocatalytic efficiency was more than three times those of pure g-C3N4 or Bi2MoO6. The enhanced photocatalytic activity of the g-C3N4/Bi2MoO6 heterostructure photocatalyst was attributed predominantly to the efficient separation of photoinduced electrons and holes. The g-C3N4/Bi2MoO6 heterojunction photocatalyst exhibited excellent stability and reusability. A detailed mechanism for the enhanced photocatalytic activity is discussed. Superoxide radicals were the major active species. This study provides a visible light responsive photocatalyst with potential in environmental remediation applications.

A strategy of employing graphene oxide (GO) nanosheets to prepare large-area GO films is proposed in this work. The films are prepared by injecting GO suspension in a mixture of water and ethanol (H2O + EtOH) at the liquid/liquid (hexane/water, C6H14/H2O) interface and forming the GO films at the interface. After evaporation of C6H14, GO films at the air/(H2O + EtOH) interface are transferred onto solid substrates by the horizontal lifting deposition, and large area (2.5 cm × 2.5 cm) of homogeneous GO films with the thickness of 5.4 nm and the roughness of 3.6 nm is obtained. The formation scheme of the GO films at the C6H14/(H2O + EtOH) interface is discussed considering the density difference between the C6H14, (H2O + EtOH), and H2O, as well as the interaction between the GO nanosheets. This facile strategy paves a new path for preparation of large ultrathin GO films from GO nanosheets, which is of great importance for the preparation of GO-based materials to be used in supercapacitor electrodes, transp...

A strategy for inhibiting aggregation of graphene oxide (GO) nanosheets is proposed in this work, which is important to understand the physical chemistry of the stability of GO and related factors. First, GO nanosheets (1.5–2.5 μm wide and 1.0 nm thick) were prepared by a modified Hummers' method. Then layer-by-layer (LbL) self-assembly of polyelectrolytes on GO nanosheets was carried out to obtain nanocapsules, whose premise is aggregation inhibition of GO based on the Debye–Huckel theory by considering the polyelectrolyte chain length and salt concentration. Low molecular weight polyelectrolytes and 0.5 mol L−1 NaCl solution proved to be essential to inhibit the aggregation of GO nanosheets. On the basis of the aggregation inhibition, GO loaded with a hydrophobic drug, paclitaxel (PTX), were encapsulated by polyelectrolytes, showing a high loading capability of 0.4 mg mg−1 and good dispersion stability. By assembling gold nanoparticles (AuNPs) in the shell, PTX was released rapidly from these nanocapsules under near infrared (NIR) irradiation. The strategy for successful aggregation inhibition of GO nanosheets in a polyelectrolyte matrix, as well as the stable loading and controlled rapid release of hydrophobic drugs, paves new paths for GO-based advanced nanomaterials and pharmaceutics.

Novel vesicles formed spontaneously from the micelle solution of DTAB, a single-tailed surfactant (STS), mediated by a rough glass surface (RGS) without any additives. The obtained STS vesicles displayed good stability upon long-term storage, exposure to high temperatures, and freeze-thawing after the removal of RGS.

Bi2MoO6/Zn–Al layered double hydroxide (LDH) hierarchical heterostructures assembled from Bi2MoO6 hierarchical hollow spheres and Zn–Al LDH nanosheets were synthesized by a low-temperature hydrothermal method. X-ray diffraction, Fourier transform-infrared spectroscopy, thermogravimetric analysis and X-ray photoelectron spectroscopy (XPS) confirmed the formation of the Bi2MoO6/Zn–Al LDH composites. Morphologies were characterized by scanning electron microscopy and transmission electron microscopy (TEM). XPS and high resolution TEM indicated the formation of a Bi2MoO6/Zn–Al LDH heterojunction. Increasing the LDH content from 0 to 27.0 wt.% caused the Brunauer–Emmett–Teller (BET) specific surface area of the composites to gradually increase. The photocatalytic degradation activity for Rhodamine B (RhB) under visible light irradiation exhibited a large enhancement, followed by a decrease, with increasing LDH content. The Bi2MoO6/Zn–Al LDH heterostructure composite with LDH content of 5.5 wt.% showed the highest photocatalytic activity and degraded 99% of RhB in 80 min, while Bi2MoO6 degraded less than 50%. The average photocatalytic efficiency is enhanced by more than 100%. The enhanced photocatalytic activity of the Bi2MoO6/Zn–Al LDH heterostructure photocatalyst was mainly attributed to the efficient separation of photoinduced electrons and holes. Superoxide radicals and holes were the major active species. The Bi2MoO6/Zn–Al LDH heterostructure photocatalyst exhibited excellent stability and reusability. A detailed mechanism for its enhanced photocatalytic activity was discussed in this study. This work provides an effective way to fabricate a series of Bi-based and LDH-containing heterostructure photocatalysts.

With the development of pervasive sensing and machine learning technologies, automated epileptic seizure detection based on electroencephalogram (EEG) signals has provided tremendous support for the lives of epileptic patients. Discrete wavelet transform (DWT) is an effective method for time-frequency analysis of EEG and has been used for seizure detection in daily healthcare monitoring systems. However, the shift variance, the lack of directionality and the substantial aliasing, limit the effects of DWT in some applications. Dual-tree discrete wavelet transform (DTDWT) can overcome those drawbacks but may increase information redundancy. For classification tasks with small dataset sizes, such redundancy can greatly reduce learning efficiency and model performance. In this work, we proposed a novel redundancy removed DTDWT (RR-DTDWT) framework for automated seizure detection. Energy and modified multi-scale entropy (MMSE) features in a dual tree wavelet domain were extracted to construct a complete picture of mental states. To the best of our knowledge, this is the first study to employ MMSE as an indicator of epileptic seizures. Moreover, a compact EEG representation can be obtained after removing useless information redundancy (redundancy between wavelet trees, adjacent channels and entropy scales) by a general auto-weighted feature selection framework via global redundancy minimization (AGRM). Through validation on Bonn and CHB-MIT databases, the proposed RR-DTDWT method can achieve better performance than previous studies.

Reading aviation wire text is an important step for aircraft wire assembly and also a challenging problem. Aviation wire text reading means to detect and recognize the serial number printed on the surface of aviation wires or aircraft cables. The main challenges of this task lie on small sizes, low contrast and background noise in images. In this paper, we propose a new method for aviation wire text detection and recognition via deep neural networks. The detection network utilizes text border features to roughly locate text regions in images. Then the coordinates of bounding boxes of texts are regressed by pixel-level predicted offsets in adjacent regions. The recognition network is capable to recognize the text regions with diverse lengths after padding strategies. In addition, a dataset of aviation wires captured by machine vision camera in the assembly workshop is developed. A flexible method to generate synthetic images of text whose characters are arranged in styles of both head-to-tail and left-to-right is presented. On aviation wire datasets, the proposed method for text detection and recognition achieves comparable performance and significantly outperforms previous approaches.

A method has been developed for the synthesis of intercalated layered double hydroxide (LDH) nanohybrids of the charge-neutral and poorly water-soluble anticancer drug camptothecin (CPT) using a coassembly route. For this route, CPT molecules were initially incorporated into the micelles of a biocompatible surfactant, such as sodium cholate (SCh) or sodium deoxycholate (SDC). The resulting negatively charged CPT-loaded micelles and the positively charged LDH nanosheets were then coassembled together into the CPT intercalated LDH nanohybrids. The resulting nanohybrids were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) and elemental analyses. The results revealed that the loading of CPT in the nanohybrids could reach as high as 13%, indicating that this route could be used to achieve the effective intercalation of charge-neutral and poorly water-soluble drugs into the LDH gallery. The in vitro release of CPT from the nanohybrids was examined, and the results showed that the release was a diffusion-controlled process and that the diffusion process through the LDH particles was the rate-limiting step. The parabolic diffusion equation effectively described the kinetic process associated with the release of CPT from the nanohybrids.

On the basis of new paleontological data, the sequence and distributions of the Middle Devonian-Tournaisian rocks on Hainan Island have been sorted out for the first time. The Devonian rocks include the Middle Devonian Jinbo Formation and the Upper Devonian Changjiang Formation, which are distributed in northwestern Hainan Island. The Jinbo Formation is represented by 631 m of littoral facies deposits, and was intruded by the Yanshanian granite in the base. The presence of chitinozoans Eisenackitina caster, Funsochitina pilosa, and Lagenochitina amottensis indicates the Givetian in age. The Changjiang Formation is made up of 140 m of neritic facies rocks, and contains the Famennian conodonts Palmatolepis gracilis sigmoidalis, Polygnathus germanus, and corals Cystophrentis kalaohoensis. The Devonian-Tournaisian transition beds, the lower part of the Jishi Formation, are composed of 61–129 m sandstone and siltstone, with gastropods Euomphalus spp. and brachiopods, and marked by conglomerate with the underlying Devonian rocks. The middle-upper part of the Tournaisian Jishi Formation consists of 100–251 m clastic and carbonate rocks, containing abundant corals Pseudoularinia irregularis, conodonts Siphonodella isosticha, trilobites Weberiphillipsia linguiformis, and brachiopods. On the basis of the occurrence of Xinanosprifer flabellum and Homotoma sp., the Nanhao Formation in southern Hainan Island is now regarded as the Lower Silurian, instead of the previously designated Lower Carboniferous. It is confirmed that no Carboniferous rocks occurred in the area south to the Gancheng-Wanning Fault.

In this paper, we describe a synthesis strategy of deoxycholate (DC) intercalated layered double hydroxide (LDH) nanohybrids via a coassembly method at room temperature. For this strategy, LDH particles were delaminated to well-dispersed 2D nanosheets in formamide, and the resulting LDH nanosheets were then coassembled with DC anions into the DC intercalated LDH (DC-LDH) nanohybrids. The so-synthesized nanohybrids were characterized by XRD, TEM, FT-IR, elemental analyses and TG-DSC. It was found that the loading amount of DC in the nanohybrids could be easily controlled by changing the ratio of DC to LDH. In addition, the nanohybrids have similar characteristics with the DC-LDH nanohybrids synthesized by the hydrothermal method, including their DC loading, crystal structure, morphology and thermal gravimetric behavior. However, this strategy exhibited the advantages of short reaction time and mild experimental conditions compared with the hydrothermal method.

In this paper, a delamination/reassembling method for the facile fabrication of ibuprofen (IBU), a non-steroidal anti-inflammatory drug, intercalated layered double hydroxide (LDH) nanohybrid was presented. In this method, LDH particles were first delaminated to well dispersed 2D nanosheets in formamide, and then the LDH nanosheets and IBU molecules coassembled into the IBU–LDH nanohybrid. The characteristics of the so-synthesized nanohybrid were the same as that of the IBU–LDH nanohybrids synthesized by the conventional methods including ion exchange, co-precipitation, reconstruction and hydrothermal methods. However, the delamination/reassembling method displayed various remarkable advantages, such as simple procedure, short reaction time, mild condition and high drug loading, compared with the conventional methods.

To evaluate the cognition and emotional response of the public in Zhejiang province during the epidemic of human H7N9 avian influenza and provide scientific support for group psychological intervention under public health emergency.57 communities in 19 counties from Hangzhou, Jiaxing and Lishui district of Zhejiang province were selected as survey sites using stratified clustered sampling method from March, 2013 to April, 2014. 2 319 ordinary civilians were chosen using convenience sampling method and 390 individuals who had close contact history with H7N9 avian influenza patients, 109 family members of patients and 281 medical workers, were selected using census method. The inclusion criteria for subjects were: subjects aged over 10 years; could complete the questionnaire independently or with the help of the investigators. A total of 2 709 subjects were surveyed by avian influenza risk perception and response questionnaire, negative emotion questionnaire was also used to see their cognition and negative emotion related to the disease. Spearman correlation analysis was used to analyze the interrelationship between public risk perception, response and negative emotions.95.10% (2 576)of the subjects have sensed the risk of epidemic and 91.00% (2 465) of the subjects have taken preventive measures in 2 709 subjects. The positive rate for depression, neurasthenia, fear, anxiety and hypochondriasis were 36.40% (986) , 37.21% (1 008) , 79.70% (2 159) , 33.41% (905) , 27.69% (750) respectively (χ(2)=1 935.89, P0.001) ;the P(50)(P(25)-P(75)) of the depression scores of patients' family members, medical workers and the general public were 0.50 (0.00-0.83), 0.17 (0.00-0.67), 0.17 (0.00-0.50) (H= 7.27, P=0.03) ; the neurasthenia scores were 0.20 (0.00-0.60), 0.2 (0.00-0.40), 0.00 (0.00-0.20) (H= 64.74, P0.001) ; fear scores were 0.83 (0.33-1.17), 0.33 (0.17-0.67), 0.33 (0.17-0.83) (H=30.03, P0.001) ; anxiety scores were 0.17(0.00-0.50), 0.00(0.00-0.33), 0.00(0.00-0.17) (H=51.82, P0.001). The neurasthenia, fear, anxiety scores (P(50)(P(25)-P(75))) for females among the public were 0.00(0.00-0.20), 0.50(0.17-0.83), 0.00(0.00-0.17), which were higher than those of male's (0.00(0.00-0.20), 0.33(0.00-0.67), 0.00(0.00-0.17)) (χ(2) values were 5.26, 27.52, 8.29, P0.05); Among medical staff, the depression, neurasthenia, fear, anxiety and hypochondriasis scores for females were 0.33(0.00-0.67), 0.20(0.00-0.40), 0.50(0.17-0.83), 0.00(0.00-0.33), 0.00(0.00-0.50) respectively, which were higher than those of males'(0.00(0.00-0.50), 0.00(0.00-0.40), 0.33(0.17-0.50), 0.00(0.00-0.17), 0.00(0.00-0.00))(χ(2) values were 7.22, 7.97, 14.46, 4.93, 5.22, P0.05); for the family members of the patients who were in poor mental conditions when doing self-assessment, their depression and neurasthenia scores were 0.50(0.08-0.96), 0.30(0.00-0.55), which were higher than those of people in good mental conditions (0.17(0.00-0.83), 0.20(0.00-0.60)) (χ(2) values were 12.95, 11.20, P0.05). Spearman correlation analysis showed that the subjects' risk perception level was positively correlated with depression, neurasthenia, fear, and hypochondriasis, with the correlation coefficients 0.07, 0.07, 0.08, 0.04, respectively (P0.05) ; the subjects' risk response level was also positively related with depression, neurasthenia, fear, anxiety and hypochondriasis, and the correlation coefficients were 0.09, 0.09, 0.12, 0.05, 0.04, respectively (P0.05).The general public was highly concerned about the epidemic of H7N9 avian influenza and developed certain levels of negative emotions. The female, equal or over 60 years old, those with poor educational level, agricultural related occupation and poor physical and psychology health were risk factors of disease related negative emotions. The subject's risk perception and response level was positively related with depression, neurasthenia, fear and hypochondriasis.

Many well-preserved silicified megalodontids found from the Jiapila Formation of the Upper Triassic in western China show great variations in the amorphous teeth and the massive hinge plate, making the internal molds vary greatly in size and shape. Thus, the internal molds of megalodontids do not always provide reliable taxonomic characters. As a result, about 3/4 of the 132 species and 6 of 9 genera of Triassic Megalodontidae erected on the basis of internal molds have to be revised. The revised definitions of genera Neomegalodon, Triadomegalodon, and Conchodon are given in this paper.

A magnetic composite of a meixnerite (Mg-Al-OH) type layered double hydroxide (LDH) and magnetite (Fe 3 O 4 ), abbreviated as Fe 3 O 4 @(Mg-Al-OH LDH), was successfully synthesized by a mechanochemical route with a two-step milling operation. In the first step, the mixture of Mg(OH) 2 , Al(OH) 3 and Fe 3 O 4 as the starting materials was milled without water for 1 h, and then with addition water for another 5 h in the second step. The so-synthesized composite has the structure of Fe 3 O 4 cores homogeneously dispersed in the LDH matrix and demonstrates super-paramagnetic behavior. This mechanochemical process provides a facile and environmentally safe method for synthesizing magnetic composites based on LDHs.

Microstructures bridge the molecular and the macroscopic scales. Disk-patterned microstructures obtained from microcapsules in this work are assembled through layer-by-layer which allowed depositing the natural polysaccharides chitosan (CS) and sodium alginate (SA) on porous CaCO3 microparticles. Besides CS and SA assembled outside CaCO3 microparticles, some CS and SA were also encapsulated by permeation in the pores of CaCO3. During the dissolution of CaCO3, the Ca2 + cations from decomposed CaCO3 were found to interact with alginate (AL) anions and to form Ca2 +–AL scaffolds. The adhesion arising from the OH groups in polysaccharides to solid surfaces was attributed to the disk-patterned microstructures. The calcium content (2.290 × 10− 10 mg) in each (CS/SA)4 microstructure amounts to about 1% of the total mass of the CaCO3 core. This work thus demonstrates the interaction between the decomposed core elements and the polysaccharides existing both inside and outside the porous cores. Such microstructures containing both Ca2 + and natural polysaccharides have potential applications in biological and medical systems.

Level set method can be effectively used to solve topology problems during the evolution of curves while the previous algorithms cannot deal with them. In recent years, there are many image segmentation algorithms based on level set method. For different applications of image processing, people have put forward the corresponding solutions, and a large number of researchers also continue to improve and enhance the efficiency and effectiveness of these algorithms. In this article, according to the development of the image segmentation methods based on level set, an overview is given for readers of different backgrounds in this field to use, and their characteristics are discussed.

Jurassic rocks are abundantly developed in the source area of the Yangtze River, South Qinghai, with the greatest thickness of 6311 m, including five stratigraphic units: Qoimaco Formation, Buqu Formation, Xiali Formation, Suowa Formation, and Xueshan Formation. Based on sufficient fossils of bivalves, ammonites, and brachiopods, the major part of these formations is ascribed to the Middle Jurassic Bathonian to Callovian. No diagnostic fossils have been found from the Lower Qoimaco Formation or Upper Xueshan Formation, which could possibly contain in part Bajocian and Oxfordian taxa respectively.

A series of carbon-graphite films was prepared via gradient heating based on polyimide (PI) and polyacrylonitrile (PAN) films under N2 atmosphere. It was observed that the segment fracture and thermal cross-linking reaction occur first during the low temperature pyrolysis process of PI and PAN films, meanwhile, the thermal cross-linking reaction changes the structure of PI and PAN. When it reaches a certain temperature, the crystal structure is further improved, and the films can be transformed into polycrystalline graphite structure. With the increase of temperature, the carbon content of films gradually increases and the thermal conductivity gets better. But these two kinds of films have different carbonization processes. The carbon graphite layer prepared by PI as precursor has a relatively smaller interplanar spacing and less flaws. The thermal conductivity of the films prepared by PI is 3.9 times of the films prepared by PAN.

Self-organized pattern of stearic acid (SA) and Eu(TTA) 3 Phen in a core/ring microstructure and the dewetting were observed by atomic force microscopy (AFM). Here TTA and Phen denote the β-diketone ligand thenoyltrifluoroacetylacetone and the synergistic ligand 1,10-phenanthroline. The core/ring microstructure obtained at low compression speed could be well kept after transfer to solid substrates and kept in humid surrounding. Otherwise dewetting of the microstructure resulting from the shrinkage of the SA core occurred after 1 h, leading to a gap about 200 nm between the core and ring. This work is helpful for further understanding the stability of self-organized microstructure in Langmuir–Blodgett (LB) films with double components.

Fluorescent microcapsules doped with europium β-diketone complex were previously fabricated by stepwise adsorption of polyelectrolytes and europium complex using the layer-by-layer (LbL) technique [Chem. Commun. (2007) 1547–1549]. In this work, the influence of thermal treatment on the morphology of rare earth-doped microcapsules was studied by atomic force microscopy (AFM). Remarkable shrinking, increase of wall thickness and decrease of surface roughness were observed after heating the rare earth-doped microcapsules until 70 °C for 30 min. Intense red light emission at 612.0 nm of the microcapsules could be clearly observed by bare eyes after thermal treatment. Diameter variation of the luminescent microcapsules induced by annealing is attributed to the molecular rearrangement of polyelectrolytes. Study on the fluorescent microcapsules with various sizes provides guidance in potential application as biological assay reagents or display elements.

A bivalve faunule of six species is described from the Upper Triassic Jiapila Formation at the headwaters of the Yangtze River, southern Qinghai, China. The new species, Neomegalodon cornutus and Quemocuomegalodon circularis, are described. The type species of Quemocuomegalodon, Q. orientus, is revised. Quemocuomegalodon orientus Yao, Sha, and Zhang (2003) is now known from abundant, well-preserved specimens that show great variation in shape, size, thickness of shell, and dentition, and the species Q. longitatus, Yao, Sha, and Zhang (2003) is now placed in synonymy with Q. orientus. There are significant morphologic differences between the external appearance of shelled specimens and the internal molds of species of Quemocuomegalodon. This suggests the need for the re-evaluation of many megalodontid species from elsewhere that are known only from internal molds.

A novel configuration of fiber laser with frequency modulation is presented. Frequency modulation, stable polarization state and narrow linewidth are realized by using the waveguide phase modulator, polarization maintaining devices and saturable absorber. It is shown that the laser output reaches 23 mW, linewidth is less than 1 kHz, polarization extinction ratio is higher than 20 dB and maximum value of frequency deviation can reach 7.5 MHz.

The structure and stability of self-assembled monolayers (SAMs) on substrates under certain forces are of great importance to thin films for their applications such as lubrication and adhesion in micromachines, corrosion inhibition, biological sensors, etc. In this paper, we investigate the degradation of arachidic acid (AA) monolayers on the mica surface via in situ tapping mode atomic force microscopy (TM-AFM) by continuously scanning at different humidities. Our results indicate that the degradation of AA monolayers varied along with the changing environmental humidity. The curves on the number of pinholes as a function of scan times and the dependence of the surface coverage on the scan times at varied humidity are also presented in this report. It was also found that the average apparent height of AA monolayers decreased with the increasing relative humidity.

We report a novel model system of precursor cellular membranes, self-assembled from micellar solution of a common anionic single-tailed amphiphile (STA), including sodium dodecyl sulfate (SDS) and sodium dodecylbenzenesulfonate (SDBS). The self-assembly process was mediated with solid surfaces of Mg2Al-CO3 hydrotalcite-like compound (HTlc), an anionic clay, in the absence of cosurfactants or any additives. The resultant STA vesicles were characterized using negative-staining and cryogenic transmission electron microscopies, as well as dynamic light scattering and steady state fluorescence techniques. Interestingly, the obtained STA vesicles displayed good stability even after the removal of the anionic clay surface (ACS), and a self-reproduction phenomenon was observed for the "preformed" STA vesicles when mixing with corresponding STA micellar solutions. More importantly, the micelle-to-vesicle transition for SDS could be still arisen in high-salinity artificial seawater under the ACS mediation. Instead of conventional fatty acid scenario, our finding provides another novel possible model for protocell-like vesicles, which are easily formed under the plausible prebiotic conditions.

Objectives The objective of this study was to determine the rate of acquired immune deficiency syndrome (AIDS) in Zhejiang province and to identify specific factors associated with progression of this disease. Methods This study utilized a retrospective cohort to identify the specific factors involved in the progression of human immunodeficiency virus (HIV) to AIDS. We collected data of patients existing in care between 2008 and 2012 from the national surveillance system databases. We performed our analyses using a multivariate Cox proportional hazards model. Results This study included 9216 HIV-positive patients (75.6 % male), which yielded 12,452 person-years (py) of follow-up-data. The AIDS progression rates were 33.9 % (2008), 33.6 % (2009), 38.1 % (2010), 30.6 % (2011) and 25.9 % (2012). We observed a significant reduction in the rate of progression Of HIV to AIDS post-2010 (Pearson χ2 = 4341.9, P 500 cells/mm3) at baseline were independently associated with lower rates of HIV progression to AIDS [HR = 0.382, 0.380, 0.187, P

This work describes a strategy of assembling horizontally oriented Ag nanoplates (AgNPTs) with PSS-Ag as the precursor of silver by the layer-by-layer (LbL) technique on planar substrates. These AgNPTs have a lateral dimension of 20–80 nm and a thickness of 9–12 nm. A corresponding formation mechanism of these AgNPTs is discussed considering the orientation of the polyelectrolytes molecules, as well as their confinement effect on the diffusion of Ag nanoparticles. The exposed horizontal surfaces of the AgNPTs correspond to low free energy; they show an active antimicrobial activity. No Staphylococcus aureus colonies appear on the nutrient agar medium inoculated and incubated with S. aureus solutions treated by LbL films containing AgNPTs. The horizontally oriented AgNPTs by the described strategy in this work not only provides a novel method for controlled assembly of AgNPTs, but also provides insight in the antimicrobial behavior of nanoplate surfaces with low free energy. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42070.

Ordered molecular monolayers of dipalmitoyl phosphatidylcholine (DPPC) were used as templates to induce the nucleation and growth of glycine crystals. It was found that α-glycine crystals were formed under the DPPC monolayers regardless of pH values of the aqueous supersaturated glycine solutions. The morphologies and orientations of the glycine crystals varied with pH of the solutions and surface pressures of the monolayers. When acidic and neutral aqueous supersaturated glycine solutions were used as subphases, the glycine crystals are plate-like habit with an elongated (0 1 0) crystal face preferentially oriented parallel to the plane of the monolayers; when basic solutions were used, the crystals are pyramidal habit. At surface pressures below 25 mN/m at the beginning of crystallization, plate-like α-glycine crystals were formed from the neutral solution; while at higher surface pressures, such as 35 and 40 mN/m, prismatic crystals were formed. The morphology of the glycine crystals can be tuned by changing the experimental conditions.

The Langmuir–Blodgett (LB) films of zinc(II)5,10,15,20-tetra[4-oxy(2-stearic acid) porphyrin] (ZnTSPP) was used as ordered molecular template to induce the growth of calcium phosphate crystals. This process at the surface of LB films was monitored in situ by Inverted Phase Contrast Microscopy (IPCM). It was found that the crystal morphologies changed from amorphous to regular crystal with the prolonging of the time. The transformation from unstable octacalcium phosphate (OCP) to the most stable hydroxyapatite (HAp) was confirmed. This process is step by step, which is different from the traditional epitaxial process.

Thin solid films containing luminescent europium complex were fabricated on glass and sol–gel formed TiO 2 surfaces modified by phosphate groups and characterized by electron probe microscopy (EPM), fluorescence microscopy (FM) and UV–vis and photoluminescent (PL) spectroscopy. It was found that the two kinds of luminescent films show different morphologies, the film fabricated on TiO 2 layer is more homogeneous, and the energy absorbed by TiO 2 can be transferred to Eu(III) ions. The thermal and mechanical stability of this inorganic–organic composite material is improved greatly and has important application in electrical and optical devices.

Three kinds of Langmuir monolayers formed by dipalmitoylphosphatidylcholine (DPPC), arachidic acid (AA), and octadecylamine (ODA) were used as templates to study the initial stage of nucleation and crystallization of calcium phosphates. It was demonstrated that the combination of calcium ions (or phosphates) to the monolayer/subphase interface is a prerequisite for subsequent nucleation. It was found that calcium phosphate dihydrate (DPCD) formed at 25.0 degrees C for 12 h has a biphasic structure containing both amorphous and crystalline phases. These results showed that calcium phosphates were formed through a multistage assembly process, during which an initial amorphous phase DPCD was followed by a phase transformation into a crystalline phase and then the most stable hydroxyapatite (HAp). This provided new insights into the template-biomineral interaction and a mechanism for biomineralization.