To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
We develop a model of the skin-friction coefficient based on scalar images in the compressible, spatially evolving boundary-layer transition. The images are extracted from a passive scalar field by a sliding window filter on the streamwise and wall-normal plane. The multi-scale and multi-directional geometric analysis is applied to characterize the averaged inclination angle of spatially evolving filtered component fields at different scales ranging from a boundary-layer thickness to several viscous length scales. In general, the averaged inclination angles increase along the streamwise direction, and the variation of the angles for large-scale structures is smaller than that for small-scale structures. Inspired by the coincidence of the increasing averaged inclination angle and the rise of the skin-friction coefficient, we propose a simple image-based model of the skin-friction coefficient. The model blends empirical formulae of the skin-friction coefficient in laminar and fully developed turbulent regions using the normalized averaged inclination angle of scalar structures at intermediate and small scales. The model prediction calculated from scalar images is validated by the results from the direct numerical simulation at two Mach numbers, 2.25 and 6, and the relative error can be less than 15 %.
This study aimed to evaluate the effectiveness of hypertension management and analyse the factors associated with blood pressure reduction within China’s primary healthcare system.
Hypertension is one of the leading risk factors for global disease burden and is strongly associated with cardiovascular diseases. In China, hypertension is a serious public health problem, but few studies have evaluated the effectiveness of hypertension management in China’s primary healthcare system.
The study sites were 24 primary healthcare institutions, selected using multistage stratified random sampling method. In each institution, hypertension patients aged at least 35 years who agreed to participate and had no disabilities or mental health problems were enrolled for hypertension management. Participants received comprehensive interventions in the primary healthcare system via a team. After a one-year intervention, data from 6575 hypertension patients were analysed to check the effectiveness of hypertension management and examined factors associated with hypertension control.
There was an overall mean reduction of 4.5 mmHg in systolic blood pressure (SBP) and 1.9 mmHg in diastolic blood pressure (DBP). The blood pressure reduction after one year was greater in rural patients than in urban patients, 6.6 mmHg versus 3.4 mmHg for SBP and 2.6 mmHg versus 1.6 mmHg for DBP, respectively. The hypertension control rate also increased more in rural areas (22.1%) than in urban areas (10.6%) after the one-year intervention. Age, body mass index, region and being in an urban area had a significant negative association with the reduction of SBP (P < 0.05). Education level and baseline SBP showed a significant positive association (P < 0.05).
Community-based hypertension management by general practitioners was feasible and effective. The effectiveness of hypertension management in rural areas was greater than in urban areas. Intervention strategies should pay more attention to patients in rural areas and western China.
Laser interaction with an ultra-thin pre-structured target is investigated with the help of both two-dimensional and three-dimensional particle-in-cell simulations. With the existence of a periodic structure on the target surface, the laser seems to penetrate through the target at its fundamental frequency even if the plasma density of the target is much higher than the laser’s relativistically critical density. The particle-in-cell simulations show that the transmitted laser energy behind the pre-structured target is increased by about two orders of magnitude compared to that behind the flat target. Theoretical analyses show that the transmitted energy behind the pre-structured target is actually re-emitted by electron ‘islands’ formed by the surface plasma waves on the target surfaces. In other words, the radiation with the fundamental frequency is actually ‘surface emission’ on the target rear surface. Besides the intensity of the component with the fundamental frequency, the intensity of the high-order harmonics behind the pre-structured target is also much enhanced compared to that behind the flat target. The enhancement of the high-order harmonics is also related to the surface plasma waves generated on the target surfaces.
Annexin A2 (ANXA2) is reported to be associated with cancer development. To investigate the roles ANXA2 plays during the development of cancer, the RNAi method was used to inhibit the ANXA2 expression in caco2 (human colorectal cancer cell line) and SMMC7721 (human hepatocarcinoma cell line) cells. The results showed that when the expression of ANXA2 was efficiently inhibited, the growth and motility of both cell lines were significantly decreased, and the development of the motility relevant microstructures, such as pseudopodia, filopodia, and the polymerization of microfilaments and microtubules were obviously inhibited. The cancer cell apoptosis was enhanced without obvious significance. The possible regulating pathway in the process was also predicted and discussed. Our results suggested that ANXA2 plays important roles in maintaining the malignancy of colorectal and hepatic cancer by enhancing the cell proliferation, motility, and development of the motility associated microstructures of cancer cells based on a possible complicated signal pathway.
In this paper, a new path-loss model for electromagnetic wave in an indoor multipath environment is proposed based on matching coefficient, polarization matching factor, and normalized field intensity direction function. This model is called the Friis-extension (Friis-EXT) model, because it operates as the Friis model under certain conditions. In addition, in the modeling process of the path-loss in an indoor environment, the reflective surfaces in the environment and form of the antenna are considered. Afterwards, the path-loss data in an indoor corridor environment are measured, and the maximum error between the theoretical value and the measured data is <7.5 dB. Finally, the Friis-EXT model is compared with some other traditional models, and the results show that the Friis-EXT model is the best one that matches the measurement data.
The present study was undertaken to investigate the antiparasitic activity of extracellular products of Streptomyces albus. Bioactivity-guided isolation of chloroform extracts affording a compound showing potent activity. The structure of the compound was elucidated as salinomycin (SAL) by EI-MS, 1H NMR and 13C NMR. In vitro test showed that SAL has potent anti-parasitic efficacy against theronts of Ichthyophthirius multifiliis with 10 min, 1, 2, 3 and 4 h (effective concentration) EC50 (95% confidence intervals) of 2.12 (2.22–2.02), 1.93 (1.98–1.88), 1.42 (1.47–1.37), 1.35 (1.41–1.31) and 1.11 (1.21–1.01) mg L−1. In vitro antiparasitic assays revealed that SAL could be 100% effective against I. multifiliis encysted tomonts at a concentration of 8.0 mg L−1. In vivo test demonstrated that the number of I. multifiliis trophonts on Erythroculter ilishaeformis treated with SAL was markedly lower than that of control group at 10 days after exposed to theronts (P < 0.05). In the control group, 80% mortality was observed owing to heavy I. multifiliis infection at 10 days. On the other hand, only 30.0% mortality was recorded in the group treated with 8.0 mg L−1 SAL. The median lethal dose (LD50) of SAL for E. ilishaeformis was 32.9 mg L−1.
Magnesium is a biodegradable material that has potential application in cardiovascular stent development: its excellent mechanical properties and blood compatibility make it highly useful in interventional therapy. Nevertheless, the following shortcomings restrict its further application: antihyperplasia function and promoting surface endothelialization. In this study, we immobilized a specific link peptide of endothelial cells, Arg-Glu-Asp-Val (REDV), onto polydopamine (PDA)-deposited Mg–Zn–Y–Nd alloy surface via covalent reaction to improve the growth of the endothelial cells. The PDA/REDV coating with optimized parameters maintained the good blood compatibility of the Mg–Zn–Y–Nd alloy at the biomimetic speed of the blood flow and significantly inhibited the growth of the vascular smooth muscle cells and macrophage attachment/activation, which indicated its better functions in antihyperplasia and anti-inflammation. In particular, the PDA/REDV coating not only showed consistent results in promoting the attachment of endothelial cells as reported elsewhere, but also displayed the ability of enhancing the viability of endothelial cells (or inhibiting apoptosis), suggesting its pro-endothelialized function through different pathways. In summary, this PDA/REDV coating addressed the above-mentioned shortcomings of the magnesium alloy, which may promise its wider application.
Given the global water challenges, solar-driven steam generation has become a renewed topic recently as an energy-efficient way for clean water production. Here, a hybrid plasmonic structure consisting of a top layer of TiN nanoparticles (NPs) and a bottom layer of mesoporous anodized alumina membrane (AAM) was rationally designed and fabricated. The top TiN NPs with broadband light absorption acted as a plasmonic heating layer, which converted the absorbed light to heat efficiently for interfacial water heating. The AAM acted as the mechanical support layer, guaranteeing the heat isolation and continuous water replenishment. With optimized thickness of the TiN top layer, a solar steam generation efficiency of 87.7% was achieved in this study. This efficiency is comparable or even higher than prior studies. The current work proves the capability of the TiN NPs as an alternative photothermal material.
The antennal sensilla of female Quadrastichus mendeli Kim & La Salle (Hymenoptera: Eulophidae: Tetrastichinae) were observed with scanning and transmission electron microscopy in this study. The antenna of Q. mendeli was geniculate, and the flagellum was composed of seven subsegments. Six distinct types of sensory receptors were observed, including sensilla basiconic capitate peg, sensilla böhm, sensilla chaetica, sensilla campaniformia, sensilla placodea and sensilla trichodea. Sensilla basiconic capitate pegs were found on the flagellomeres, and Böhm sensilla were found on the basal part of scape and the pedicel. Two morphological subtypes of sensilla chaetica were found on the antennae, and sensilla campaniformia were only found on the pedicel. Sensilla placodea were divided into two morphological subtypes that were found on the flagellomeres. Sensilla trichodea were found on the 2nd–6th flagellomere. By comparison to existing antennal sensilla, it was found that sensilla basiconic capitate peg, sensilla chaetica, sensilla placodea and sensilla trichodea were the most common sensilla of the parasitoids of Eulophidae. The external and internal morphology, types, number, distribution, length, and width of these sensilla were described, and their possible functions are discussed in conjunction with the host-detection behavior. Future studies on the host location mechanisms in Q. mendeli will be facilitated by these observations.
Northeastern China is a region of high tick abundance, multiple tick-borne pathogens and likely human infections. The spectrum of diseases caused by tick-borne pathogens has not been objectively evaluated in this region for clinical management and for comparison with other regions globally where tick-transmitted diseases are common. Based on clinical symptoms, PCR, indirect immunofluorescent assay and (or) blood smear, we identified and described tick-borne diseases from patients with recent tick bite seen at Mudanjiang Forestry Central Hospital. From May 2010 to September 2011, 42% (75/180) of patients were diagnosed with a specific tick-borne disease, including Lyme borreliosis, tick-borne encephalitis, human granulocytic anaplasmosis, human babesiosis and spotted fever group rickettsiosis. When we compared clinical and laboratory features to identify factors that might discriminate tick-transmitted infections from those lacking that evidence, we revealed that erythema migrans and neurological manifestations were statistically significantly differently presented between those with and without documented aetiologies (P < 0.001, P = 0.003). Twelve patients (6.7%, 12/180) were co-infected with two tick-borne pathogens. We demonstrated the poor ability of clinicians to identify the specific tick-borne disease. In addition, it is necessary to develop specific laboratory assays for optimal diagnosis of tick-borne diseases.
Environmental characteristics (for example, temperature, photoperiod) as seasonal cues can affect the offspring sex ratio and reproductive tactics of many hymenopteran insects. Leptocybe invasa Fisher & La Salle is the most critical invasive insect pest of Eucalyptus spp. in the world and displays thelytokous reproduction. In the current study, we studied the effects of temperature and photoperiod on offspring sex ratio and reproductive tactics in L. invasa. Results show that sex ratio (female: male) of L. invasa was under 15, 25 and 35 °C with both L 12: D 12 and L 16: D 8, and cold and thermal acclimation were 74.5:1, 71.0:1, 59.0:0, 17.3:1, 53.0:0, 64.0:0, 47.0:1 and 56.0:0, respectively, which was highly significantly female biased and with no significant difference due to temperature or photoperiod. Offspring virgin females oviposited and induced the bump-shaped galls on plants under the same conditions as described above. Constant temperature, photoperiod and their interaction, and cold and thermal acclimation had no significant effect on the infestation rates of Eucalyptus branches induced by offspring virgin females. Thus, temperature, photoperiod and cold and thermal acclimation did not influence female-biased sex ratio and tactics with thelytokous reproduction of offspring females in L. invasa.
Curcumin has been attributed with antioxidant, anti-inflammatory, antibacterial activities, and has shown highly protective effects against enteropathogenic bacteria and mycotoxins. Ochratoxin A (OTA) is one of the major intestinal pathogenic mycotoxins. The possible effect of curcumin on the alleviation of enterotoxicity induced by OTA is unknown. The effects of dietary curcumin supplementation on OTA-induced oxidative stress, intestinal barrier and mitochondrial dysfunctions were examined in young ducks. A total of 540 mixed-sex 1-day-old White Pekin ducklings with initial BW (43.4±0.1 g) were randomly assigned into controls (fed only the basal diet), a group fed an OTA-contaminated diet (2 mg/kg feed), and a group fed the same OTA-contaminated feed plus 400 mg/kg of curcumin. Each treatment consisted of six replicates, each containing 30 ducklings and treatment lasted for 21 days. There was a significant decrease in average daily gain (ADG) and increased feed : gain caused by OTA (P<0.05); curcumin co-treatment prevented the decrease in BW and ADG compared with the OTA group (P<0.05). Histopathological and ultrastructural examination showed clear signs of enterotoxicity caused by OTA, but these changes were largely prevented by curcumin supplementation. Curcumin decreased the concentrations of interleukin-1β, tumor necrosis factor-α and malondialdehyde, and increased the activity of glutathione peroxidase induced by OTA in the jejunal mucosa of ducks (P<0.05). Additionally, curcumin increased jejunal mucosa occludin and tight junction protein 1 mRNA and protein levels, and decreased those of ρ-associated protein kinase 1 (P<0.05). Notably, curcumin inhibited the increased expression of apoptosis-related genes, and downregulated mitochondrial transcription factors A, B1 and B2 caused by OTA without any effects on RNA polymerase mitochondrial (P<0.05). These results indicated that curcumin could protect ducks from OTA-induced impairment of intestinal barrier function and mitochondrial integrity.
The BeiDou navigation satellite system (BDS) has been providing a regional service in the Asia–Pacific area since 27 December 2012, and a new Inclined Geosynchronous Satellite Orbit (IGSO) satellite IGSO-6 joined the 14-satellite constellation in operation on 29 March 2016. In this paper, the signal and positioning performance of IGSO-6 are assessed. Compared with other IGSOs, the carrier-to-noise-density ratios of IGSO-6 show comparable performance for the B3 signal and a lower power level for the B2 signal, while the B1 signal is more powerful and has the lowest noise and multipath errors. The satellite-induced code bias of IGSO-6 was investigated and indicates that IGSO-6 has similar characteristics to other IGSOs. The different inter-frequency bias variations among IGSOs with daily periodicity are demonstrated. The BDS positioning performances with IGSO-6 were investigated in Single Point Positioning (SPP) and Precise Point Positioning (PPP) modes at the 95% confidence level. For SPP, there was an improvement of about 4·9% and 3·6% in the horizontal and vertical components, respectively. The convergence time was improved by about 18·3% and 17·8% in the horizontal and vertical components for positioning accuracy to be better than 50 cm, respectively.
The study investigated whether different dietary energy and protein sources affect laying performance, antioxidant status, fresh yolk fatty acid profile and quality of salted yolks in laying ducks. In all, 360 19-week-old Longyan ducks were randomly assigned to four diets in a factorial arrangement (2×2). The four diets consisted of two energy sources, corn (CO) or sorghum (SO) and two protein sources, soybean meal (SM) and rapeseed meal with corn distillers dried grains with solubles (RMD), and each treatment contained six replicates of 15 birds each. The experimental diets were isocaloric (metabolizable energy, 10.84 MJ/kg) and isonitrogenous (CP, 17%). The results showed that egg production, average egg weight, egg mass and feed conversion ratio were not affected by diets (P>0.05). Plasma contents of reduced glutathione (GSH), GSH/oxidized glutathione and total antioxidant capacity were lower (P<0.05) in ducks fed the RMD diets compared with those fed SM diets with a substantial increase (P=0.006) in plasma content of malondialdehyde (MDA). Egg yolks from ducks fed SO diets had higher proportions of polyunsaturated fatty acids (PUFA) and lower saturated and monounsaturated fatty acids compared with CO diets (P<0.001). Similarly, ducks fed RMD diets had a higher content of PUFA and n-6/n-3 ratio in fresh yolks (P<0.001), and increased salted yolk MDA, carbonylated proteins content and incidence of hard salted yolks (P<0.05) compared with SM diets. Scanning electron microscopy showed that salted yolks contained rougher polyhedral granules and fewer fat droplets, and were surrounded with a layer of bunchy fibers in ducks fed SO+RMD than those fed CO+SM diet. In conclusion, the current study showed that feeding laying ducks with diets containing SO or RMD reduced antioxidant capacity and increased egg yolk concentrations of PUFA. It appeared that egg yolks from ducks fed these diets were more sensitive to lipid peroxidation and protein oxidation during salting, and reduced the quality of salted yolks.
The study investigated whether dietary methionine (Met) affects egg weight and antioxidant status through regulating gene expression of ovalbumin (OVAL), nuclear factor erythroid 2 like 2 (Nrf2) and haem oxygenase 1 (HO-1) in laying duck breeders. Longyan duck breeders (n 540, 19 weeks) were randomly assigned to six treatments with six replicates of fifteen birds each. Breeders were fed diets with six Met levels (2·00, 2·75, 3·50, 4·25, 5·00 and 5·75 g/kg) for 24 weeks. The egg weight (g), egg mass (g/d), feed conversion ratio, hatchability, 1-d duckling weight, albumen weight, albumen proportion and OVAL mRNA level improved with dietary Met levels, whereas yolk proportion decreased (P<0·05). The weight of total large yellow follicles increased linearly (P<0·001) and quadratically (P<0·05) with dietary Met concentration, and their weight relative to ovarian weight showed a linear (P<0·05) effect. Dietary Met level had a linear (P<0·05) and quadratic (P<0·001) effect on the gene expression of glutathione peroxidase (GPX1), HO-1 and Nrf2, and quadratically (P<0·05) increased contents of GPX and total antioxidant capacity (T-AOC) in liver of duck breeders. In addition, maternal dietary Met enhanced gene expression of GPX1, HO-1 and Nrf2, increased contents of GPX and T-AOC and reduced carbonylated protein in the brains of hatchlings. Overall, dietary Met concentration affected egg weight and albumen weight in laying duck breeders, which was partly due to gene expression of OVAL in oviduct magnum. A diet containing 4·0 g Met/kg would achieve optimal hepatic GPX1 and Nrf2 expression, maximise the activity of GPX and minimise lipid peroxidation.
Multistage magmatic thermal events occurred in the Yardoi Dome and contain important information on the tectonomagmatic processes. The dome has played a crucial role in understanding the collisional evolution of the Tethyan Himalayan. We present new geochronological and geochemical data for muscovite-granite exposed in the Liemai area, Eastern Tethyan Himalayan Belt. Liemai muscovite-granite is strongly peraluminous, with A/CNK values characterized by evolved geochemical composition with high contents of SiO2-enriched large-ion lithophile elements, and is depleted of high-field-strength elements. These geochemical features indicate that granites possibly derived from partial melting of metasedimentary rocks and plagioclase fractional crystallization probably played a critical role in production of peraluminous granitic melts. Zircon U–Pb dating from muscovite-granite yielded ages of approximately 48.5 ± 1.1 Ma, representing its crystallization ages. This age is the oldest age of Tethyan Himalayan leucogranite from the Yardoi Dome and adjacent areas. However, the inherited zircon cores have ages of 135.7–3339.2 Ma. The εHf(t) values of all zircons vary from –6.4 to –2.3 and have varying Hf-isotope crustal model ages of 731–839 Ma. The geochemical and isotopic compositions indicate that magma of the Liemai granite can most likely be interpreted as products of the break-off related to thermal perturbation along the break-off window associated with the subduction of Neo-Tethyan slab. These magmas were derived mainly from the anatexis of ancient crustal materials under contraction and thickening conditions due to subduction of the Indian continent beneath southeastern Tibet.