Host density is a key regulatory factor in parasite transmission. The goldfish (Carassius auratus)-Gyrodactylus kobayashii model was used to investigate effects of host density on population growth of gyrodactylids. A donor fish infected by five gravid gyrodactylids was mixed with 11 parasite-free goldfish at five host densities. There was a significant positive correlation between host density and mean abundance of G. kobayashii throughout the 58-day experiment. During early infection (days 15–24), mean abundance in medium high (0.5 fish L−1) and high host density groups (1 and 2 fish L−1) was significantly higher than that in the low host density groups (0.125 and 0.25 fish L−1). At high host density, prevalence increased more rapidly, and the peak prevalence was higher. Fitting of an exponential growth model showed that the population growth rate of the parasite increased with host density. A hypothesis was proposed that higher host density contributed to increased reinfection of detached gyrodactylids. A reinfection experiment was designed to test this hypothesis. Both mean abundance and prevalence at a host density of 1 fish L−1 were significantly higher than those at 0.25 fish L−1 on days 1 and 3, which suggested that more reinfections of G. kobyashii occurred at the higher host density. Density-dependent transmission during the early infection was an important contributor of population growth of G. kobayashii, as well as density-dependent reinfection of the detached gyrodactylids.

Nitrogen is an important element for the growth of flue-cured tobacco and is closely related to its yield and quality. In order to pursue higher economic benefits, excessive fertilizer is generally applied in flue-cured tobacco production, which is unfavourable for the sustainable development of flue-cured tobacco production and for the environment. In 2016 and 2017, experiments using different nitrogen fertilizer application rates in flue-cure tobacco were conducted in Yunnan province, and the changes in agronomic, economic and chemical indices as well as in residual soil nitrogen were compared. Linear and quadratic models were used to compare the response of tobacco to nitrogen fertilizer. With increasing nitrogen fertilizer rate, the proportions of superior to medium tobacco and the average price of flue-cured tobacco leaves initially increased and then decreased, while fresh weight, dry weight and the proportion of inferior tobacco showed the opposite trend. Total sugar and reducing sugar contents decreased with increasing nitrogen fertilizer rates, while total nitrogen and nicotine contents increased. Sensory evaluation scores had the highest value when 90 kg N/ha and 120 kg N/ha were applied. Soil nitrate contents increased as nitrogen fertilizer rate increased. The quadratic model was suitable for the response of cultivar K326 to nitrogen and 90 kg N/ha could meet the needs of cultivar K326.

The prevalence of impaired fasting glucose (IFG) and diabetes mellitus (DM) has reportedly increased significantly among Chinese children and adolescents. We aimed to examine the prevalence of IFG and DM, the disparities in sex and region and related risk factors among Chinese children and adolescents. A total of 16 434 Chinese children aged 6–17 years were selected from a national cross-sectional survey, and fasting glucose was measured for all participants. Overall, mean fasting plasma glucose (FPG) concentration was (4·64 (sd 0·51)) mmol/l, and the prevalence of DM and IFG was 0·10 and 1·89 %, respectively. Compared with girls, boys had higher FPG concentration (4·69 v. 4·58 mmol/l, r 0·107, P<0·001) and IFG prevalence (2·67 v. 1·07 %, rφ 0·059, P<0·001). Compared with rural children and adolescents, urban children and adolescent had higher FPG concentration (4·65 v. 4·62 mmol/l, r 0·029, P<0·001) and DM prevalence (0·15 v. 0·05 %, rφ 0·016, P<0·01). In addition, self-reported fried foods intake and overweight/obesity were positively associated with IFG, and the proportion of consuming fried foods more than or equal to once per week and overweight/obesity prevalence in boys and urban children and adolescents were significantly higher than girls and rural children and adolescents, respectively (P<0·05). Although the prevalence of IFG and DM was relatively low in Chinese children and adolescents, sex and region disparities were observed, which may be associated with differences in overweight/obesity prevalence and dietary factors.

Gold–silver (Au–Ag) bimetal dispersed SiO2 composite films were fabricated via a chemical solution approach combining sol–gel with a spin-coating process, and they were investigated by transmission electron microscopy (TEM), x-ray photoelectron spectroscopy (XPS), and ultraviolet-visible absorption spectra. TEM image indicated that Ag and/or Au nanoparticles (NPs) had a spherical structure with large size distributions. The XPS results demonstrated that the presence of both Ag and Au NPs in the composite film is in each metal state. The optical absorption spectra of the composite film further confirmed the formation of nanosized Au and Ag particles, given by the two surface plasmon resonance (SPR) peaks. Unlike other Au–Ag composite films, these two SPR peaks had almost the same intensity, which is rarely obtained by a chemical approach. Compared to optical absorption spectra calculated by the modified Mie theory, the location and intensity of SPR peaks had a little difference, which could be attributed to large size distributions of Ag and Au bimetal NPs in the composite film along with the experimental process. In addition, the intensity of both SPR peaks was content-related.

Defining asset poverty as insufficiency of assets to satisfy household basic needs for a limited period of time, the study examines asset-poverty rates in urban China using the 2002 survey data from the Chinese Household Income Project (CHIP). We find that asset-poverty rates in urban China are lower than those of developed countries, in part due to Chinese households’ strong commitment to precautionary savings and the low poverty standards. However, the liquid asset-poverty rate is five times that of the income-poverty rate in urban China. Notably, the asset-poverty-gap ratio shows that most households in asset poverty have zero liquid assets or negative net worth. Asset building could be an integral part of the anti-poverty agenda to protect the poor from economic hardship and provide them with opportunities for economic growth.

Nanoindentation was performed on amorphous silicon nitride films of different thicknesses deposited on gallium arsenide (GaAs) (001) substrates using a conical indenter. Both “pop-in” and ‘pop-out’ were observed from the load-displacement curves when the indentation load exceeded a critical value. Pop-in occurring during loading is associated with plane-slip in the GaAs substrate, and pop-out during unloading is attributed to the interfacial delamination between the film and the substrate. Finite element modeling (FEM) was used to analyze the stress evolution during unloading. The FEM results showed that the stress at the interface evolved from compressive to tensile status during the withdrawal of indentation load, and the interfacial debonding was induced at a critical tensile stress, which is consistent with the pop-out observed. A deformation model for interpreting the pop-in and pop-out events is thereby proposed.

The ordered structures in different doping levels (x = 0.1, 0.15, 0.2, 0.25, 0.3) of yttrium doped ceria (YDC, Ce(1−x)YxO2−δ) electrolytes were investigated by electron diffraction, high-resolution transmission electron microscopy (TEM), scanning TEM, and electron energy loss spectroscopy. Oxygen vacancy ordering was experimentally confirmed within the ordered structures. With increasing the doping level, the concentration of trivalent Ce cations was increased in YDC samples and such trivalent Ce cations were supposed to mainly exist in the ordered structures. Based on our electron microscopic observation and microanalysis, a crystal model for the ordered structures is proposed.

In this study, Pd thin film is used as catalyst to grow epitaxial InAs nanowires on GaAs(111)B substrate in a metal-organic chemical vapor deposition reactor to explore the growth mechanism and the effects of non-gold catalysts in the growth of III-V epitaxial nanowires. Through detailed morphological, structural and chemical characterization using scanning and transmission electron microscopy, it is found that defect-free zinc-blende structured epitaxial InAs nanowires are grown along the <110> directions with four {111} sidewall facets forming a diamond shaped cross-section. Furthermore, the interface between the nanowire/catalyst is found to be the uncommon {113} planes. It is anticipated that these zinc-blende structured InAs nanowires are grown via the vapor-liquid-solid mechanism. The defect-free nature of these nanowires arises from the non-<111> growth direction and non-{111} nanowire/catalyst interface.

Nanosized incubational domain was observed in 10 at.% gadolinium-doped ceria (GDC) using high-resolution transmission electron microscopy. Dislocations were extensively observed in 10 at.% GDC instead of heavily doped 25 at.% GDC. By Fast Fourier Transform and Inverse Fast Fourier Transform analysis, it was noticed that the incubational domain existing in 10 at.% GDC has different lattice spacing and orientation from the neighboring ceria matrix. Furthermore, dislocations were usually observed in the interface region between the incubational domain and the ceria matrix. Based on experimental results, the formation mechanism of dislocation associated incubational domain in lightly gadolinium-doped ceria is rationalized.

Aimed at designing an efficient visible light active photocatalyst and suppressing the self-corrosion tendency of CdS nanoparticles, a novel composite consisting of CdS nanoparticles and exfoliated two-dimensional (2D) TiO2 nanosheets was successfully fabricated using a simple self-assembly process. The prepared samples were characterized using various techniques including x-ray diffraction, ultraviolet–visible absorption spectroscopy, x-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. It was found that the exfoliated 2D nanosheets played an important role as an ultrathin coating to suppress the photocorrosion of CdS nanoparticles, evidenced by inductively coupled plasma-atomic emission spectrometer analysis. The resultant CdS/TiO2 composites exhibited enhanced photocatalytic activity in the oxidation of Rhodamine B in water under visible light irradiation (λ > 420 nm).

The Hutubi Rural Social Security Loan programme is a policy innovation in a rural area of China, which loans savings in social security accounts back to peasants for them to buy assets for agricultural and other development. In contrast to the nationwide recession in rural social security, this programme has shown its success in proliferating rural social security funds and retaining social security participants. With a focus on the administrative data of the loan programme, this study aims to provide an in-depth understanding of the loan programme and examine how asset building is possible for the poor when institutional incentives are offered. The findings show that when proper policy incentives are provided, poor peasants can build assets. The Hutubi programme may be a good model for other rural areas in China and other developing countries.

In this study, we report the growth of metallic tungsten nanowires induced by alloy catalysts (Fe–Ni) at a temperature of 850 °C. The synthesized tungsten nanowires have bottom diameters of 100 to 400 nm and tip diameters of <80 nm, and show a well-defined single-crystalline structure. The formation of the (Fe,Ni)-catalyzed W nanowires should be controlled by the vapor–solid–solid mechanism, rather than the traditional vapor–liquid–solid mechanism, because the growth temperature is significantly below the lowest eutectic temperature (1455 °C) of the Fe–Ni–W ternary system. Our study demonstrates the feasibility of synthesizing metallic nanowires via metal-catalyzed methods, which may be extended to the synthesis of some other metallic nanowires.

To observe the axial growth behavior of InAs on GaAs nanowires, InAs was grown for different growth durations on GaAs nanowires using Au nanoparticles. Through transmission electron microscopy, we have observed the following evolution steps for the InAs growth. (1) In the initial stages of the InAs growth, InAs cluster into a wedge shape preferentially at an edge of the Au/GaAs interface by minimizing Au/InAs interfacial area; (2) with further growth of InAs, the Au particles move sidewards and then downwards by preserving an interface with GaAs nanowire sidewalls. The lower interfacial energy of Au/GaAs than that of Au/InAs is attributed to be the reason for such Au movement. This downward movement of Au nanoparticle later terminates when the nanoparticle encounters InAs growing radially on the GaAs nanowire sidewalls, and with further supply of In and As vapor reactants, the Au nanoparticles assist the formation of InAs branches. These observations give some insights of vapor-liquid-solid growth and the kinks formation in nanowire heterostructures.

This paper presents the results of a study to identify the effects of preheating for plasma oxidation (ashing) of patterned Polydimethylsiloxane (PDMS) for Bio-MEMS applications. PDMS creates an irreversible seal to itself as well as strong seals with glass, silicon, and silicon nitride. This process activates the surface by producing hydroxyl groups that last for several minutes to allow bonding. Several channels can be stacked to create 3D systems for microfluidic applications using PDMS alone or in combination with other materials to develop hybrid systems. For PDMS, bonding temperatures typically occur at room temperature. This research investigates the effect of preheating the materials prior to ashing. The investigators successfully demonstrate good bonding of PDMS to slides with a work adhesion on the order of 100 mJm-2. Preheating the samples at 65°C results in significant increase in work adhesion depending on mixture. The effects of processing temperature and chemical components on bond quality and work of adhesion are reported.

Temperature and power dependent photoluminescence measurements were carried out on the multi-layer structure of GeSi dots grown on Si(001) substrate by gas-source molecular beam epitaxy. The transfer of photon-induced carriers from wetting layers into the dots and the region near the dots was evidenced. Different power dependent behaviors of the photoluminescence peak position were observed for the dots and the wetting layer. Accordingly, type-II and type-I band alignments were proposed for the dots and the wetting layers, respectively. After annealing, the photoluminescence peaks from the dots and the wetting layers showed blueshift due to the atomic intermixing. For the samples annealed at temperature above 850°C for 5min, the band alignment of the dots changes from type-II to type-I.

In the present study, the new system used C3F8 and H2 as source gases. Filament-assisted chemical vapor deposition was utilized. Continuous diamond films were grown on the Si and Mo substrates without any surface pretreatment. The results of scanning electron microscopy, Raman spectroscopy, X-ray diffraction, and atomic force microscopy measurements indicate that the films deposited on the Mo substrates are of high quality. Homoepitaxial diamond films were grown on the high pressure synthetic single crystal diamond substrates. The results show that in our experimental conditions epitaxial films were easily grown on the (111) synthetic diamond substrates and sometimes epitaxial filmse also grown on the (100) synthetic diamond substrates.