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.
A magnetic dipole quasi-Yagi antenna based on a dielectric resonator (DR) is proposed in this letter. The dominate TE1δ1 mode of the rectangular DR is used as a magnetic dipole which can be differentially fed by the coplanar strip line (CPS). Thanks to the DR employment, the proposed antenna has several advantages such as compact size and flexible design which means the 3-D dimensions of the DR can be easily adjusted to cater for various applications. Meanwhile, the gain of the proposed DR quasi-Yagi antenna is higher than that of traditional electric dipole counterparts. Furthermore, since the DR driver is horizontally polarized, both the metal strip and DR can be used as a director for enhancing the end-fire gain. To verify the design concept, a prototype operating at the X-band is fabricated and measured. Good agreement between the simulated and measured results can be observed.
The present study was carried out to evaluate the effect of dietary supplemental vitamin D3 (VD3) on P absorption and utilisation as well as its related mechanisms in the small intestine of broilers. A total of 384 1-d-old Arbor Acres male broilers were assigned randomly into four treatments following a completely randomised design with a 2 (dietary non-phytate P (NPP) contents: 0·43 and 0·22 %)×2 (dietary VD3 supplemental levels: 0 and 87·5 μg/kg) factorial arrangement. The experiment lasted for 22 d. The results showed that P contents in serum from the hepatic portal vein and tibia ash of broilers were higher (P<0·05) for 0·43 % NPP than for 0·22 % NPP. The type IIb Na-dependent phosphate cotransporter (NaP-IIb) protein expressions in the duodenum and ileum were higher (P<0·05) also for 0·43 % NPP than 0·22 % NPP. Supplementation of VD3 enhanced (P<0·05) tibia P retention rate and type III Na-dependent phosphate cotransporter (PiT)-1 protein expression in the duodenum of all broilers. Moreover, VD3 supplementation decreased (P<0·002) mortality and increased (P<0·02) serum P content from the hepatic portal vein after 4 h of feeding, tibia ash content, tibia ash P content and protein expressions of NaP-IIb and PiT-1 in the jejunum of broilers fed diet with 0·22 % NPP. Thus, dietary supplemental VD3 promoted intestinal P absorption and bone P utilisation, and this effect might be associated with enhanced PiT-1 levels in the duodenum and PiT-1 and NaP-IIb levels in the jejunum respectively when dietary NPP is limiting.
Palladium (Pd) and gold (Au) nanoparticles (NPs) hybridized on two types of carbon supports, graphene and granular activated carbon (GAC), were shown to be promising catalysts for the sustainable hydrodehalogenation of aqueous trichloroethylene (TCE). These catalysts are capable of degrading TCE more rapidly than commercial Pd-on-GAC catalysts. The catalysts were synthesized at room temperature without the use of any environmentally unfriendly chemicals. Pd was chosen for its catalytic potency to break down TCE, while Au acts as a strong promoter of the catalytic activity of Pd. The results indicate that both graphene and GAC are favorable supports for the NPs due to high surface-to-volume ratios, unique surface properties, and the prevention of NP aggregation. The properties of NP catalysts were characterized using electron microscopy and spectroscopy techniques. The TCE degradation results indicate that the GAC-supported catalysts have a higher rate of TCE removal than the commercial Pd-on-GAC catalyst, and the degradation rate is greatly increased when using graphene-supported samples.
Monosized spherical Cu–20% Sn (wt%) alloy particles with diameter ranging from 70.6 to 334.0 μm were prepared by the pulsated orifice ejection method (termed “POEM”). Fully dense without pores and bulk inclusions, the cross-sectional micrographs of the spherical alloy particles indicate an even distribution of Cu and Sn. These spherical Cu–Sn alloy particles exhibit a good spherical shape and a narrow size distribution, suggesting that the liquid Cu–Sn alloy can completely break the balance between the surface tension and the liquid static pressure in the crucible micropores and accurately control the volume of the droplets. Furthermore, the cooling rate of spherical Cu–20% Sn alloy particles is estimated by a Newton’s cooling model. The cooling rate of the Cu–20% Sn alloy particle decreases gradually with the particle diameter increasing. Smaller particles have higher cooling rates and when the particle diameter is less than 70 μm, the cooling rate of particles can reach more than 3.3 × 104 K/s. The secondary dendrite arm spacing has strong dependence on particle diameter which increases gradually with the increase of particle diameter. The results demonstrate that POEM is an effective route for fabrication of high-quality monosized Cu–20% Sn alloy particles.
To investigate the P absorption and gene expression levels of related co-transporters, type IIb sodium-dependent phosphate co-transporter (NaPi-IIb), inorganic phosphate transporter 1 (PiT-1) and inorganic phosphate transporter 2 (PiT-2) in the small intestine of broilers, 450 1-d-old Arbor Acres male broilers were randomly allocated to one of three treatments with ten replicate cages of fifteen birds per cage for each treatment in a completely randomised design. Chickens were fed a diet with no added inorganic P (containing 0·06 % non-phytate P (NPP)) or with either 0·21 or 0·44 % NPP for 21 d. Plasma P concentration in the hepatic portal vein, mRNA and protein expression levels of NaPi-IIb, PiT-1 and PiT-2 were determined at 7, 14 and 21 d of age. The results showed that the concentration of P in plasma in the hepatic portal vein increased as dietary NPP increased (P<0·0001). At 14 and 21 d of age, the increase in dietary NPP inhibited (P<0·003) NaPi-IIb mRNA expression level in the duodenum, as well as PiT-1 mRNA and protein expression levels in the ileum, but promoted NaPi-IIb protein expression level (P<0·002) and PiT-2 mRNA and protein expression levels (P<0·04) in the duodenum. These results suggest that NaPi-IIb, PiT-1 and PiT-2 might be important P transporters in the small intestine of broilers. Higher intestinal P absorption may be achieved by up-regulating the protein expression levels of NaPi-IIb and PiT-2 and down-regulating the protein expression of PiT-1.
The Chinese government has recently expanded the scope of urban social insurance programmes. However, social protection for the labour force of the urban informal sector, which reaches about half the number of urban workers, lags significantly behind. This under-coverage may be due to institutional constraints, particularly the household registration system hukou, and self-selection behaviour related to the limited benefits of social insurance. Drawing on a recent nationwide individual-level survey and city-level statistics, this study examines these two explanations for the under-enrolment on the social insurance programme. First, results suggest that hukou and the intergovernmental fiscal system are major institutional constraints. Second, self-selection behaviour in programme enrolment is verified. Employers in the informal sector are likely to opt out of social insurance. More importantly, employers in the informal sector, with rural or non-local hukou, are likely to opt out of social insurance, which suggests that self-selection behaviour is constrained by institutions. Such findings have important implications for broad theoretical and policy debates on universal social protection.
From continental to regional scales, the zoonosis alveolar echinococcosis (AE) (caused by Echinococcus multilocularis) forms discrete patches of endemicity within which transmission hotspots of much larger prevalence may occur. Since the late 80s, a number of hotspots have been identified in continental Asia, mostly in China, wherein the ecology of intermediate host communities has been described. This is the case in south Gansu, at the eastern border of the Tibetan plateau, in south Ningxia, in the western Tian Shan of Xinjiang, and in the Alay valley of south Kyrgyzstan. Here we present a comparative natural history and characteristics of transmission ecosystems or ecoscapes. On this basis, regional types of transmission and their ecological characteristics have been proposed in a general framework. Combining climatic, land cover and intermediate host species distribution data, we identified and mapped 4 spatially distinct types of transmission ecosystems typified by the presence of one of the following small mammal ‘flagship’ species: Ellobius tancrei, Ochotona curzoniae, Lasiopodomys brandtii or Eospalax fontanierii. Each transmission ecosystem had its own characteristics which can serve as a reference for further in-depth research in the transmission ecology of E. multilocularis. This approach may be used at fine spatial scales to characterize other poorly known transmission systems of the large Eurasian endemic zone, and help in consideration of surveillance systems and interventions.
Most CuIn(SexS1−x)2 (CISS) thin films are deposited via conventional two-stage process. However, a significant problem related to the conventional two-stage process is the separation of CuInSe2 and CuInS2 phases. In this article, single-phase CISS thin films have been successfully prepared by selenizing sulfides of copper and indium. The mixed sulfides of Cu–In precursors were synthesized by coprecipitation method and then partly reduced. The inks containing partly reduced powders and organic binders were deposited onto glass substrate using a spin-coating technique. After coating, the precursor films were selenized to get CISS. X-ray diffraction and energy dispersive x-ray spectroscopy data show that the single (112) peak position changed with the variation of Se/S ratio. The absorption energy Egchanges linearly with Se/(Se + S) calculated by ultraviolet–vis absorption spectra. Those results confirm the formation of single-phase CISS with homogenous composition.
To determine the association between major dietary patterns characterized by factor analysis and risk of depression and anxiety symptoms among adolescents.
Diet and symptoms of depression and anxiety were assessed in a cross-sectional survey among students attending junior high school. Dietary patterns were derived from a self-reported FFQ, which consisted of thirty-eight items. Anthropometric measurements were also performed.
Four junior high schools in Bengbu city, China.
A random sample of 5003 adolescents, 11–16 years of age (mean 13·21 years).
Three major dietary patterns were identified in the study based on factor analysis: ‘snack’, ‘animal food’ and ‘traditional’. The prevalence of depression symptoms, anxiety disorders and the coexistence of both were 11·2 % (560/5003), 14·6 % (732/5003) and 12·6 % (629/5003), respectively. After adjustment for potential confounders, adolescents in the highest tertile of snack dietary pattern scores had a higher odds for ‘pure’ psychological symptoms (‘depression without anxiety’, OR = 1·64; 95 % CI 1·30, 2·06; and ‘anxiety without depression’, OR = 1·87; 95 % CI 1·51, 2·31) compared with coexisting depression and anxiety (OR = 1·93; 95 % CI 1·54, 2·43). Similar to snacks, high consumption of animal foods was associated with a higher risk of psychological symptoms. Compared with low consumption, adolescents in the highest tertile of traditional dietary pattern scores had lower odds for ‘pure’ depression (OR = 0·38; 95 % CI 0·30, 0·49), ‘pure’ anxiety (OR = 0·85; 95 % CI 0·69, 1·04) and coexisting anxiety and depression (OR = 0·50; 95 % CI 0·39, 0·63).
Data from Chinese secondary-school adolescents validated findings from adult populations. Dietary patterns should be considered as important predictors of depression and anxiety among adolescents in further studies.
Pyroelectric thin film detectors have advantages of wavelength independent sensitivity, room temperature operation and direct incorporation with integrated circuit amplifiers. Pyroelectric thin films with good quality have be prepared by many advanced thin film technologies [1-2]. The responsivity of pyroelectric thin film detectors is dependent on the thermal properties of the substrate, on which pyroelectric thin film detectors are prepared. The heat conduction in the detectors was investigated using the one-dimensional heat flow equation and the expressions describing the detectors performance were derived for pyroelectric thin films detectors with multilayer structure. The numerical simulation showed that the pyroelectric thin film detectors need effective heat isolation. If the air gap could be the heat isolation layer, which is between the bottom electrode and substrate, the iesponsivity of detectors would be higher than that of detectors which have no heat isolation in certain modulation frequency range.
A new method is developed to directly exhibit glass transition in Zr-Ti-Cu-Ni-Be bulk glass-forming alloy under high pressure in metallic glass. Via the method, we derive an increase of glass transition temperature, Tg with pressure of 5.6 K/GPa, and a formation volume (ΔVf) of 6.5 Å3 for diffusion and the migration volume (ΔVm) of 6.5 Å3. The glass transition under high pressure is simulated based on the free-volume theory, and the simulations are consistent with the experimental observations.
The rabbit defensin gene NP-1 was introduced into embryonic callus cultures of three maize (Zea mays L.) hybrid lines by particle bombardment, and transgenic plants were obtained. Genomic PCR and DNA dot blot analyses confirmed that the NP-1 gene was integrated into the genome of the regenerated T0 maize plants. Genomic PCR and Southern blotting results revealed that the NP-1 gene was transmitted stably from the T0 to the T1 generation. RNA dot blot analysis verified the transcription of the NP-1 gene in T1 plants. When challenged with northern corn leaf blight (Helminthosporium turcicum Pass), the T1 plants expressing the NP-1 gene showed greatly improved resistance to the fungal disease compared with the wild-type maize plants.
The quantitative relationships between the position of the mastoid segment of the facial nerve, mastoid pneumatization and the positions of neighbouring structures are undetermined. Using high resolution computed tomography (HRCT), the positions of these structureswere measured in 66 normal temporal bones. A new method for measuring the volume of pneumatization in the temporal bone based on the serial digital images of CT was designed. The method of partial correlation analysis was used to find the real relationship of the two variables. The results suggest that the factors that influence the position of the mastoid segment of the facialnerve are complicated and multiple. The development of the cranium including the temporal bone,the temporal bone pneumatization and the variable position of the jugular bulb are considered to be important factors.
Email your librarian or administrator to recommend adding this to your organisation's collection.