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.
The association between milk consumption and the metabolic syndrome remains inconclusive, and data from Chinese populations are scarce. We conducted a cross-sectional study to investigate the association between milk consumption and the metabolic syndrome and its components among the residents of Suzhou Industrial Park, Suzhou, China. A total of 5149 participants were included in the final analysis. A logistic regression model was applied to estimate the OR and 95 % CI for the prevalence of the metabolic syndrome and its components according to milk consumption. In addition, the results of our study were further meta-analysed with other published observational studies to quantify the association between the highest v. lowest categories of milk consumption and the metabolic syndrome and its components. There was no significant difference in the odds of having the metabolic syndrome between milk consumers and non-milk consumers (OR 0·86, 95 % CI 0·73, 1·01). However, milk consumers had lower odds of having elevated waist circumference (OR 0·78, 95 % CI 0·67, 0·92), elevated TAG (OR 0·83, 95 % CI 0·70, 0·99) and elevated blood pressure (OR 0·85, 95 % CI 0·73, 0·99). When the results were pooled together with other published studies, higher milk consumption was inversely associated with the risk of the metabolic syndrome (relative risk 0·80, 95 % CI 0·72, 0·88) and its components (except elevated fasting blood glucose); however, these results should be treated with caution as high heterogeneity was observed. In summary, the currently available evidence from observational studies suggests that higher milk consumption may be inversely associated with the metabolic syndrome.
Indentation and scratch models are proposed to numerically investigate effects of compressive prestress on film's mechanical responses. In indentation, normal stress distributions are strongly dependent on film thickness; the applied force and the maximum normal stresses with a prestress are much larger than without prestress. For various film thicknesses the change in the normal force in scratch between the non-prestressed and prestressed films is 4%–23%. The scratch friction coefficient is larger with prestress than without prestress. With biaxial or uniaxial prestress the material becomes more difficult to deform or to slide at the contact surface compared with cases without prestress.
Suicidal behaviours in adolescents are prevalent and multifactorial. This study was conducted to examine the associations between exposure to suicide attempt (ESA) or suicide death (ESD) and suicidal behaviours in a large sample of Chinese adolescents.
Participants included for the analysis were 11 831 adolescent students who participated in the baseline survey of the Shandong Adolescent Behavior and Health Cohort (SABHC). Participants were sampled from five middle and three high schools in three counties of Shandong province, China. A self-administered structured questionnaire was used to collect data on demographics, behavioural and emotional problems, family environment, suicidal behaviours (suicidal thought, plan and attempt), and history of ESA or death of a family member, relative, friend or close acquaintance. Based on the sources of exposure, the participants were divided into four groups: non-exposure, exposure from relatives only, exposure from friends/close acquaintances only (EFO) and exposure from both relatives and friends (ERF). Logistic regressions were used to examine the associations between ESA or ESD and suicidal behaviours.
Mean age of the participants was 14.97 ± 1.46 years and 50.9% were boys. Of the participants, 9.4% reported having ESA, and 6.6% reported having ESD. The prevalence rates of suicidal behaviours were significantly higher in adolescents who had been exposed to suicide attempt or death than those who had not. Multivariate logistic regressions showed that ESA and ESD were both significantly associated with increased risks of suicidal thought (ESA: OR = 1.96, 95% CI = 1.66–2.31; ESD: OR = 1.59, 95% CI = 1.31–1.94), plan (ESA: OR = 2.37, 95% CI = 1.84–3.05; ESD: OR = 1.62, 95% CI = 1.18–2.23) and attempt (ESA: OR = 2.73, 95% CI = 1.92–3.89; ESD: OR = 1.82, 95% CI = 1.18–2.82), respectively. When participants were exposed to suicide attempt, ERF and EFO groups had significantly higher risks of suicidal thought (ERF: OR = 2.61, 95% CI = 1.28–1.64; EFO: OR = 1.96, 95% CI = 1.64–2.36), plan (ERF: OR = 3.72, 95% CI = 2.04–6.78; EFO: OR = 2.31, 95% CI = 1.74–3.01) and attempt (ERF: OR = 4.83, 95% CI = 2.30–10.17; EFO: OR = 2.57, 95% CI = 1.73–3.81), respectively.
ESA or ESD was associated with increased risks of suicidal behaviours in adolescents. Exposure to suicidal behaviours of relatives and friends/close acquaintances appeared to have different influence on adolescent suicidal behaviours. Further research is warranted to examine the biological and psychosocial mechanisms between suicidal exposure and subsequent suicidal behaviours in adolescents.
The semilocal convergence of a third-order Newton-like method for solving nonlinear equations is considered. Under a weak condition (the so-called γ-condition) on the derivative of the nonlinear operator, we establish a new semilocal convergence theorem for the Newton-like method and also provide an error estimate. Some numerical examples show the applicability and efficiency of our result, in comparison to other semilocal convergence theorems.
We studied the evolution, genotypes, and the molecular clock of dengue virus serotype 1 (DENV-1), between 2001 and 2014 in Guangzhou, China. The analysis of the envelope (E) gene sequences of 67 DENV-1 strains isolated in Guangzhou, together with 58 representative sequences downloaded from NCBI, have shown shifts in viral genotypes. The genotype changed several times, from genotype I to IV in 2002, from IV to I in 2005, and from I to V in 2014. These genotype shifts may be the cause of DENV outbreaks. The diversity of genotypes and clades demonstrates a high risk of future outbreaks in Guangzhou. The mean rate of virus nucleotide substitution in Guangzhou was determined to be 7·77 × 10−4 per site per year, which represents a medium substitution rate compared to two other countries. Our research can point to different ancestors of the isolated strains, which may further reveal the different origins and transmission of DENV-1 strains in Guangzhou.
As a unique tubular nanoclay, halloysite nanotubes (HNTs) have recently attracted significant research attention. The HNTs have outer diameters of ∼50 nm, inner lumens of ∼20 nm and are 200–1000 nm long. They are biocompatible nanomaterials and widely available in nature, which makes them good candidates for application in biomedicine. Compared with other types of nanoparticles such as polymer nanoparticles and carbon nanotubes, the drawbacks associated with HNTs include brittleness, difficulty with fabrication, low fracture strength, high density and inadequate biocompatibility. Preparation of polysaccharide-HNT composites offer a means to overcome these shortcomings. Halloysite nanotubes can be incorporated easily into polysaccharides via solution mixing, such as with chitosan (CS), sodium alginate, cellulose, pectin and amylose, for forming composite films, porous scaffolds or hydrogels. The interfacial interactions, such as electrostatic attraction and hydrogen bonding, between HNTs and the polysaccharides are critical for improvement of the properties. Morphology results show that HNTs are dispersed uniformly in the composites. The mechanical strength and Young's modulus of the composites in both the dry and wet states are enhanced by HNTs and the HNTs can also increase the storage modulus, glass-transition temperature and thermal stability of the composites. Cytocompatibility results demonstrate that the polysaccharide-HNT composites have low cytotoxicity even for HNT loading >80%. Therefore, the polysaccharide-HNT composites show great potential for biomedical applications, e.g. as tissue engineering scaffold materials, wound-dressing materials, drug-delivery carriers, and cell-isolation surfaces.
A series of zeolite–zeolite composites were prepared by a two-step hydrothermal crystallization procedure in which the mixture of presynthesized ZSM-5 zeolite acts as nutrients for the growth of postsynthesized Y zeolite, and the as-synthesized products are denoted as MFI–FAU. The structural, crystalline, and textural properties of the as-synthesized materials, as well as the references Y, ZSM-5, and a corresponding physical mixture composed of Y and ZSM-5 zeolite, were characterized by x-ray powder diffraction (XRD), Fourier transform infrared spectrum (FTIR), temperature-programmed desorption of ammonia, N2 adsorption–desorption, scanning electron microscopy, energy-dispersive spectrometry, and Thermogravimetry. The results show that the ratio of Y to ZSM-5 in the composite can be adjusted by controlling the hydrothermal treatment time of the second-step synthesis. Steric hindrance provoked by the concurrently growing crystals offers the postsynthesized Y zeolite phase, a relatively smaller size. A hierarchical pores system, which results from the extraction of silicon species from ZSM-5 and the polycrystalline accumulation of Y zeolite, has been created in the zeolite–zeolite composite. Catalytic performances of the zeolite–zeolite composite catalysts as well as the references catalysts were investigated during the catalytic cracking of isopropylbenzene. As compared with the corresponding physical mixture, the composite catalysts display the excellent catalytic performances with a higher conversion of isopropylbenzene as well as a longer catalytic life because of the introduced hierarchical pores system and the formation of special composite structure.
Shape-memory epoxy is receiving considerable attention because of its superior mechanical and thermal properties and excellent shape-memory performance. In this study, a novel series of shape-memory epoxy resins are prepared using hydro-epoxy, hexahydrophthalic anhydride, and diglycidyl 4,5-epoxy tetrahydro phthalate (TDE-85) to further improve the recovery force of shape-memory epoxy resins. The thermal, mechanical, and shape-memory properties of the shape-memory epoxy resin system are investigated by differential scanning calorimetry, dynamic mechanical analysis, bend test, and shape recovery test. Results indicate that the glass transition temperature (Tg), rubber modulus, and room-temperature bend strength increase as TDE-85 content increases. Investigation of the shape-memory behavior of the resin reveals that full recovery can be achieved after only several minutes when the temperature is equal to or above Tg. The shape recovery time decreases with the increase in TDE-85 content at Tg, Tg + 10 °C, and Tg + 20 °C. These results are attributed to the increase in TDE-85 content.
This study aimed to explore whether the presence of a Y chromosome azoospermia factor (AZF) microdeletion confers any adverse effect on embryonic development and clinical outcomes after intracytoplasmic sperm injection (ICSI) treatment. Fifty-seven patients with AZF microdeletion were included in the present study and 114 oligozoospermia and azoospermia patients without AZF microdeletion were recruited as controls. Both AZF and control groups were further divided into subgroups based upon the methods of semen collection: the AZF-testicular sperm extraction subgroup (AZF-TESE, n = 14), the AZF-ejaculation subgroup (AZF-EJA, n = 43), the control-TESE subgroup (n = 28) and the control-EJA subgroup (n = 86). Clinical data were analyzed in the two groups and four subgroups respectively. A retrospective case–control study was performed. A significantly lower fertilization rate (69.27 versus 75.70%, P = 0.000) and cleavage rate (89.55 versus 94.39%, P = 0.000) was found in AZF group compared with the control group. Furthermore, in AZF-TESE subgroup, the fertilization rate (67.54 versus 74.25%, P = 0.037) and cleavage rate (88.96 versus 94.79%, P = 0.022) were significantly lower than in the control-TESE subgroup; similarly, the fertilization rate (69.85 versus 75.85%, P = 0.004) and cleavage rate (89.36 versus 94.26%, P = 0.002) in AZF-EJA subgroup were significantly lower than in the control-EJA subgroup; however, the fertilization rate and cleavage rate in AZF-TESE (control-TESE) subgroup was similar to that in the AZF-EJA (control-EJA) subgroup. The other clinical outcomes were comparable between four subgroups (P > 0.05). Therefore, sperm from patients with AZF microdeletion, obtained either by ejaculation or TESE, may have lower fertilization and cleavage rates, but seem to have comparable clinical outcomes to those from patients without AZF microdeletion.
Discovery of ultra-compact dwarfs (UCDs) in the past 15 years blurs the once thought clear division between classic globular clusters (GCs) and early-type galaxies. The intermediate nature of UCDs, which are larger and more massive than typical GCs but more compact than typical dwarf galaxies, has triggered hot debate on whether UCDs should be considered galactic in origin or merely the most extreme GCs. Previous studies of various scaling relations, stellar populations and internal dynamics did not give an unambiguous answer to the primary origin of UCDs. In this contribution, we present the first ever detailed study of global dynamics of 97 UCDs (rh ≳ 10 pc) associated with the central cD galaxy of the Virgo cluster, M87. We found that UCDs follow a different radial number density profile and different rotational properties from GCs. The orbital anisotropies of UCDs are tangentially-biased within ~ 40 kpc of M87 and become radially-biased with radius further out. In contrast, the blue GCs, which have similar median colors to our sample of UCDs, become more tangentially-biased at larger radii beyond ~ 40 kpc. Our analysis suggests that most UCDs in M87 are not consistent with being merely the most luminous and extended examples of otherwise normal GCs. The radially-biased orbital structure of UCDs at large radii is in general agreement with the scenario that most UCDs originated from the tidally threshed dwarf galaxies.
A microwave rectifier at 5.8 GHz without any capacitors is presented, which owns a measured MW-to-DC conversion efficiency of 68.1%. A harmonic rejection filter and a DC pass filter, which replace lumped capacitors in conventional microwave rectifiers, are applied to suppressing the harmonics produced by an HSMS-286 Schottky diode during rectifying. At the fundamental frequency, a microstrip impedance transformer which contains a shunt λg/8 short-ended microstrip transmission line and two short series microstrip transmission lines are applied to compensating the imaginary impedance of the diode and matching the input impedance of the rectifier. The measured MW-to-DC conversion efficiency agrees well to the simulated results. The novel rectifier without any lumped passive elements may be applied for power transmission system at higher microwave frequencies.
Multilayer thin films have been widely used for their enhanced mechanical and tribological properties relative to the monolayers of equivalent thickness. However, the mechanical properties of the each constituent layer are rarely investigated due to the difficulty in separating the effects of the constituent layers. An inverse analysis method to identify the elastic moduli of the constituent layers of multilayer films is developed by fitting the finite element calculations with indentation measurements within the framework of numerical optimization. The method is verified against typical monolayer, bilayer, and trilayer film structures both numerically and experimentally. Uniqueness and substrate-independence of the extracted moduli are ensured by the multiple loading–unloading cycles of the indentation tests. The method provides a feasible way to characterize the intrinsic mechanical properties of the constituent layers of multilayered thin films and further to explore the dominant mechanism for the enhancement of their mechanical properties.
In this work, the relationship between the substrate crystallinity and the on-state resistances of silicon carbide (SiC) photoconductive semiconductor switches (PCSSs) was investigated. PCSSs with different channel lengths were fabricated on semi insulating 6H–SiC having different crystal qualities. A method was introduced for determining the photoconductive capacity of the SiC PCSSs. The experimental data suggest that the photoconductive capacity decreases sharply with the degradation of the full width at half maximum of the rocking curve of the 6H–SiC substrates. It is found that increasing the carrier mobility is a key factor for reducing the on-state resistance of the 6H–SiC PCSSs. Moreover, the results in this work present reference for the selection of 6H–SiC substrates for the fabrication of PCSSs and some other photoelectric devices.
Ultrathin SiC buffer layers have been grown on Si (100) substrates by atmospheric pressure chemical vapor deposition. The evolution of buffer layer morphological properties as a function of carbonization parameters is investigated by atomic force microscopy. Based on the quantitative analysis of the dependences of void density, void depth, void width, and surface roughness on carbonization parameters, a buffer layer growth model is proposed, and the effects of carbonization parameters on buffer layer morphology are clarified. The void density is related to the carbonization temperature, temperature ramp-up rate, and C3H8 concentration by affecting the initial SiC nuclei density. The void size is evolved with processing time and mainly dependent on the carbonization temperature but slightly affected by C3H8 and H2. The buffer layer morphology is deteriorated with increasing H2 flow rate when the C3H8 concentration is fixed.
The hexagonal mesoporous silica MCM-41 nanospheres with Au nanorods (AuNRs) as core have been synthesized via a modified Stöber method by a process of hydration and condensation of tetraethoxysilane in a water–ethanol mixture. The AuNR@MCM-41 nanocomposites combine the photothermal characteristic with the mesopore of MCM-41 in one body. We utilized these core–shell materials for ibuprofen encapsulation and release in the simulated body fluid (pH 7.4) for the first time. The results certificated AuNR@MCM-41 nanocomposites as novel dual-functional materials could realize the light-driven release of drug due to the photothermal effect of the AuNRs. Such novel nanomaterials offer a new way for cancer treatment which combine hyperthermia with the chemotherapeutic drugs by synergistic effect.
Intense non-thermal radiation spikes were observed prior to energy quench in HT-7 tokamak. The dynamic properties of non-thermal electrons have been analyzed. Observation manifests that some non-thermal electrons are confined in the vicinity of q = 1 magnetic surface which results in hot spot phenomenon just before disruption.
We consider nonparametric estimation of spectral densities of stationary processes, a fundamental problem in spectral analysis of time series. Under natural and easily verifiable conditions, we obtain consistency and asymptotic normality of spectral density estimates. Asymptotic distribution of maximum deviations of the spectral density estimates is also derived. The latter result sheds new light on the classical problem of tests of white noises.
The structural gene encoding ApxII toxin (apxIIA) was amplified from the genomic DNA of Actinobacillus pleuropneumoniae (APP) strain HB08 (serotype 2) and cloned into the prokaryotic expression vector pET-28a. SDS-PAGE and Western blot analysis showed that the apxIIA gene was expressed in Escherichia coli BL21 (DE3) and the expressed products could react with ApxII antibodies. The recombinant ApxIIA was purified from the inclusion bodies. Kunming mice were intraperitoneally vaccinated twice, with an interval of 2 weeks, using unfolded/refolded recombinant proteins, the native ApxII toxin extracted from the cultural supernatant of a strain of APP serotype 7 (APP-7) or phosphate-buffered saline (PBS). Serum antibody was examined by ApxIIA-specific enzyme-linked immunosorbent assay (ELISA) 2 weeks after every vaccination. Two weeks after the second vaccination, mice were challenged intraperitoneally with a lethal dose of APP-7 (1.08 × 108 cfu per mouse). The protection rate reached 91.7% in the native ApxII group, 83.3% in the refolded recombinant protein group and 58.3% in the unfolded recombinant protein group, while all mice in the PBS group died within 36 h after challenge. Our data revealed that the refolded recombinant ApxIIA had excellent immunogenicity and could elicit protection against a lethal challenge of APP.
The Gushan diorite pluton, located at the northern margin of the North China block, was emplaced during Middle Devonian times (SHRIMP U–Pb zircon age of 390 ± 5 Ma). Rocks from the pluton are characterized by low SiO2 and high alkali contents, and they show monzodiorite compositions in a total alkali v. silica (TAS) plot. They exhibit light REE-enrichment, no to slightly positive Eu anomalies, strong depletion in Rb, Th, U, Nb, Ta, P, Zr, Hf and Ti, enrichment in Ba, K and Sr, low contents of Y and Yb, and high Sr/Y ratios. They have a relatively narrow range of isotopic compositions with initial 87Sr/86Sr ratios of ∼ 0.7050, εNd(T) values of −9.5 to −7.5 and zircon εHf(T) values from −11.8 to −5.8. These features are remarkably similar to another Middle Devonian intrusion, the Shuiquangou syenitic complex at the northern margin of the North China block. These similarities suggest that the two intrusions probably have a common origin. They were considered to be derived from a type I enriched mantle, ultimately with some involvement of ancient lower crustal components, and were likely emplaced in a back-arc extension environment related to southward subduction of the Palaeo-Asian oceanic plate or during the cessation of the subduction. Aluminium-in-hornblende barometry studies of the Middle Devonian Gushan pluton yielded emplacement depths of about 18 km. Combined with previous geobarometry results on the Carboniferous plutons within the Inner Mongolia Palaeo-uplift on the northern margin of the North China block, it is inferred that the uplift and exhumation of the plutons within the Inner Mongolia Palaeo-uplift during Middle Devonian to Late Carboniferous times were not as distinct as those during Late Carboniferous to Early Jurassic times, and the strong uplift and exhumation of the Inner Mongolia Palaeo-uplift were achieved during Late Carboniferous to Early Jurassic times.
The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is a major worldwide pest of cruciferous vegetables (Talekar and Shelton 1993). Male and female adults of this species can be accurately identified by visible differences in their external genitalia. According to Robertson (1939), the sex of pupae can also be identified, but, in our experience, this approach is more difficult. For some types of research, determination of larval sex would be useful. For example, one could determine sex-specific responses of larvae to a treatment by observing mortality, development rate, or behavior of male and female larvae separately. In studies requiring hybrid mating between different strains of diamondback moth (Tabashnik et al. 1992), one could isolate groups of male larvae separately from female larvae to avoid mating within a strain. Some lepidopteran larvae can be sexed by the gonads being visible through the cuticle of the fifth abdominal segment or by the position of external pits marking the location of the genital discs in the eighth and ninth abdominal segments (Stehr 1987). But, because of their small size, it is not practical to sex diamondback moth larvae by external pits and we have found no studies in which male and female larvae were identified by gonadal form. Herein we report that third- and fourth-instar larvae of diamondback moth can be sexed efficiently and reliably.