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.
AlMgB14–TiB2 ceramic was successfully brazed to TC4 alloy with inactive AgCu filler alloy. X-ray diffractometer, SEM, and energy-dispersive spectrometer were used to study interfacial microstructure and shear strength of the joints under different brazing temperatures. The results indicated that the typical microstructure of the TC4/AlMgB14–TiB2 joint was TC4/Ti(s.s) + Ti2Cu/Ti2Cu/TiCu/TiCu2Al/Ag(s.s) + Cu(s.s)/TiB whiskers/TiB2 reaction layer/AMBT. By increasing the brazing temperature, the thickness of the TC4 diffusion layer was improved, whereas that of the brazing seam decreased remarkably. When the brazing temperature was increased to 880 °C, the brazing seam was composed of Ti–Cu intermetallic Ag(s.s) with a few Cu(s.s), TiCu2Al distributed. Meanwhile, the formation of a continuous TiB2 reaction layer at the interface of the AMBT and brazing filler facilitated the improvement of joint shear strength. The joint with the maximum shear strength of 46.7 MPa was obtained while brazing at 880 °C for 10 min.
Soil moisture is a key factor in the ecohydrological cycle in water-limited ecosystems, and it integrates the effects of climate, soil, and vegetation. The water balance and the hydrological cycle are significantly important for vegetation restoration in water-limited regions, and these dynamics are still poorly understood. In this study, the soil moisture and water balance were modelled with the stochastic soil water balance model in the Loess Plateau, China. This model was verified by monitoring soil moisture data of black locust plantations in the Yangjuangou catchment in the Loess Plateau. The influences of a rainfall regime change on soil moisture and water balance were also explored. Three meteorological stations were selected (Yulin, Yan'an, and Luochuan) along the precipitation gradient to detect the effects of rainfall spatial variability on the soil moisture and water balance. The results showed that soil moisture tended to be more frequent at low levels with decreasing precipitation, and the ratio of evapotranspiration under stress in response to rainfall also changed from 74.0% in Yulin to 52.3% in Luochuan. In addition, the effects of a temporal change in rainfall regime on soil moisture and water balance were explored at Yan'an. The soil moisture probability density function moved to high soil moisture in the wet period compared to the dry period of Yan'an, and the evapotranspiration under stress increased from 59.5% to 72% from the wet period to the dry period. The results of this study prove the applicability of the stochastic model in the Loess Plateau and reveal its potential for guiding the vegetation restoration in the next stage.
A novel luminogen-functionalized SBA-15, denoted as SNT, was developed by incorporating tris(4-bromophenyl)amine (TBPA) into SBA-15 via a “fixation-induced emission” strategy. The emission of TBPA on the matrix of SBA-15 was greatly enhanced, making the SNT possible as a fluorescence sensor. Cefalexin, a typical antibiotic, was chosen as the model analyte to be assayed and sensitive detection performance was achieved. This is the first time for cefalexin to be detected by a fluorescent method. Moreover, the SNT can be recycled by simply washing with proper solvents then used for next detection. This work provides a strategy to greatly improve the emission characteristics of fluorophores, even if a mediocre small fluorophore. It can be extended to design practical fluorescent sensors with high performance and recyclability by this strategy.
Sulphur isotopes can be used as a powerful tool to trace fluid evolution and explore the formation of chimneys. To clarify the in situ S isotopic variations of sulphides at the micro-scale, we analyzed a sulphide chimney collected from the hydrothermal field in the East Pacific Rise 1–2° S using a sensitive high-mass-resolution ion micro-probe for stable isotopes (SHRIMP SI). Three mineral zones can be identified in the chimney: an external outer wall of porous anhydrite and colloform pyrite, an internal middle zone of sub-euhedral pyrite and massive chalcopyrite, and an inner zone of massive pyrite. The δ34SV-CDT values of the sulphides fall within the range 1.83–7.51 ‰ (avg. 4.05 ‰, n = 16), and S isotopic values increase from the core (3.09 ‰, n = 3) to the middle (3.78 ‰, n = 11) to the edge (6.99 ‰, n = 2). These results illustrate mineral crystallization processes and the mixing between seawater-derived S and magmatic–hydrothermal fluids during the growth of the chimney. The zones from the edge to the core are characterized by crystal morphologies of colloform/anhedral pyrite to massive pyrite with decreasing δ34S values, revealing multi-stage mineral deposition and sulphur isotopic fractionation. In contrast to the increase in δ34S values from the core to the edge in one profile (profile A), anomalously low δ34S values in fine-grained pyrite relative to chalcopyrite in another profile (profile B) in the middle zone result from S isotopic exchange between seawater SO42− and fluid H2S due to different fluid–seawater mixing, possibly caused by variations in permeability and porosity across the chimney.
Since 2010, Jankowski’s Bunting Emberiza jankowskii has been listed as ‘Endangered’ on the IUCN Red List of Threatened Species. However, because no comprehensive surveys had been conducted, it was not known whether undiscovered populations existed elsewhere, so the population status of the species could not be assessed accurately. The aim of this study was to assess the breeding distribution and population size of Jankowski’s Bunting in China. Fifty sites in Inner Mongolia, and Jilin, Heilongjiang, Liaoning and Hebei Provinces were surveyed to locate suitable habitat and breeding populations of Jankowski’s Bunting. The surveyed sites included historical breeding distribution areas, wintering sites, and regions adjacent to historical breeding distribution areas. We confirmed that Jankowski’s Bunting has disappeared from most of its former breeding distributions, with the exceptions of Dagang, Xiergen and Tumiji. Additionally, 13 new breeding sites were discovered in Inner Mongolia. All currently known populations breed in Mongolian steppe-vegetation zones, with shrubs dominated by the natural Siberian apricot Prunus sibirica, indicating that this type of habitat is crucial for the survival of the species. Based on remote sensing, the suitable breeding habitat for Jankowski’s Bunting is estimated to be approximately 280 km2. The population size of Jankowski’s Bunting could range between 9,800 and 12,500 individuals, which is much higher than the numbers estimated in previous reports that were based on partial surveys. The suitable habitat remaining in Inner Mongolia would highly benefit from the implementation of the National Key Public Forest Protection Project. The population size of Jankowski’s Bunting is larger than previously estimated, but it is still threatened by habitat degradation and fragmentation, and our survey results reinforce the need for more research. The status of Jankowski’s Bunting in China still meets the IUCN criteria B2ab for an ‘Endangered’ species.
First principles was carried out studying the properties of (Ti, Nb)C compounds based on density functional theory. The integration of mechanical behavior, electronic structures, and thermodynamic properties can be optimized by mediating the concentration of the titanium alloying element. The results revealed that these transition metal compounds were stable with the negative formation energy. Nb0.5Ti0.5C (29.15 GPa) demonstrated the largest hardness characterized by moduli (B, G) because of the stable shell configuration. NbC exhibited the strongest anisotropy from the universal anisotropic index (AU) and three-dimensional surface contours. TixNb1−xC compounds displayed relatively strong stress responses along the , , and  directions. Due to the weakening p–d bonding, the ideal tensile strength gradually decreased with the increasing titanium concentration. The electronic structures revealed that the bonding characteristics of the (Ti, Nb)C compounds were a mixture of metallic and covalent bonds. On the other hand, NbC and TiC exhibited a minimum (740.55 K) and maximum (919.29 K) Debye temperature, indicating the stronger metalic bonds of NbC and covalent bonds of TiC.
The neuropsychological origins of negative syndrome of schizophrenia remain elusive. Evidence from behavioural studies, which utilised emotion-inducing pictures to elicit motivated behaviour generally reported that that schizophrenia patients experienced similar affective experience as healthy individuals but failed to translate emotional salience to motivated behaviour, a phenomenon called emotion–behaviour decoupling. However, a few studies have examined emotion–behaviour decoupling in non-psychotic high-risk populations, who are relatively unaffected by medication effects.
In this study, we examined the nature and extent of emotion–behaviour decoupling in in three independent samples (65 schizophrenia patients v. 63 controls; 40 unaffected relatives v. 45 controls; and 32 individuals with social anhedonia v. 32 controls). We administered an experimental task to examine their affective experience and its coupling with behaviour, using emotion-inducing slides, and allowed participants to alter stimulus exposure using button-pressing to seek pleasure or avoid aversion.
Schizophrenia patients reported similar affective experiences as their controls, while their unaffected relatives and individuals with high levels of social anhedonia exhibited attenuated affective experiences, in particular in the arousal aspect. Compared with their respective control groups, all of the three groups showed emotion–behaviour decoupling.
Our findings support that both genetically and behaviourally high-risk groups exhibit emotion–behaviour decoupling. The familial association apparently supports its role as a putative trait marker for schizophrenia.
We examined the in vitro developmental competence of parthenogenetic activation (PA) oocytes activated by an electric pulse (EP) and treated with various concentrations of AZD5438 for 4 h. Treatment with 10 µM AZD5438 for 4 h significantly improved the blastocyst formation rate of PA oocytes in comparison with 0, 20, or 50 µM AZD5438 treatment (46.4% vs. 34.5%, 32.3%, and 24.0%, respectively; P < 0.05). The blastocyst formation rate was higher in the group treated with AZD5438 for 4 h than in the groups treated with AZD5438 for 2 or 6 h (42.8% vs. 38.6% and 37.2%, respectively; P > 0.05). Furthermore, 66.67% of blastocysts derived from these AZD5438-treated PA oocytes had a diploid karyotype. The blastocyst formation rate of PA and somatic cell nuclear transfer (SCNT) embryos was similar between oocytes activated by an EP and treated with 2 mM 6-dimethylaminopurine for 4 h and those activated by an EP and treated with 10 µM AZD5438 for 4 h (11.11% vs. 13.40%, P > 0.05). In addition, the level of maturation-promoting factor (MPF) was significantly decreased in oocytes activated by an EP and treated with 10 µM AZD5438 for 4 h. Finally, the mRNA expression levels of apoptosis-related genes (Bax and Bcl-2) and pluripotency-related genes (Oct4, Nanog, and Sox2) were checked by RT-PCR; however, there were no differences between the AZD5438-treated and non-treated control groups. Our results demonstrate that porcine oocyte activation via an EP in combination with AZD5438 treatment can lead to a high blastocyst formation rate in PA and SCNT experiments.
In this paper we consider new perturbation bounds analysis of a kind of generalized saddle point systems. We provide perturbation upper bounds for the solutions of generalized saddle point systems, which extend the corresponding results in [W.-W. Xu, W. Li, New perturbation analysis for generalized saddle point systems, Calcolo., 46(2009), pp. 25-36] to more general cases.
The microstructure, room temperature compressive property, and elevated temperature tensile property of directionally solidified NiAl–Cr(Mo)–(Hf,Dy) hypereutectic alloy were investigated. The directional solidifications of liquid metal cooling technique (LMC) and zone melted liquid metal cooling technique (ZMLMC) were adopted. In the LMC alloy, the well-aligned and fully eutectic lamellar structure parallel to the growth direction is obtained. The interlamellar spacing gradually decreases with increasing the withdrawal rate, and the compressive yield strength gradually increases. In the ZMLMC alloy, the eutectic lamellar structure is disordered and not parallel to the growth direction, and the quantities of Cr(Mo) primary phases are observed. Compared to the ZMLMC alloy, the LMC alloy has a better combination property because of the well-aligned lamellar structure. The observations of crack propagation and fracture surface are performed to better understand the fracture behavior.
The aim of this study was to explore whether the morphology of polar bodies (PBs) estimated at 16–18 h after insemination can be used as an additional marker for predicting human embryo quality or pregnancy outcome. The data from 355 patients who received standard in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) treatment after controlled ovarian hyperstimulation were recruited. Normal fertilized 3048 zygotes from 382 cycles were divided into two groups, PBs intact or fragmented, according to the morphology of PBs assessed at 16–18 h after insemination. Embryo quality and pregnancy outcome were compared between the two groups. It was shown that the day 3 (D3) good embryo rate, good quality blastocyst rate and available embryo rate of the PBs intact group were all significantly higher than that of the corresponding fragmented groups. However, no significant differences in pregnancy rate (PR) or implantation rate (IR) were observed between the intact and fragmented groups. Although PBs morphology estimated at 16–18 h after insemination had little effect on PR or IR in fresh embryo transfer cycles, a better embryo quality can be achieved in the PB-intact group, which is valuable for embryo selection.
This study investigated the influences of neighborhood factors (residential stability and neighborhood disadvantage) and variants of the serotonin transporter linked polymorphic region (5-HTTLPR) genotype on the development of substance use among African American children aged 10–24 years. To accomplish this, a harmonized data set of five longitudinal studies was created via pooling overlapping age cohorts to establish a database with 2,689 children and 12,474 data points to span ages 10–24 years. A description of steps used in the development of the harmonized data set is provided, including how issues such as the measurement equivalence of constructs were addressed. A sequence of multilevel models was specified to evaluate Gene × Environment effects on growth of substance use across time. Findings indicated that residential instability was associated with higher levels and a steeper gradient of growth in substance use across time. The inclusion of the 5-HTTLPR genotype provided greater precision to the relationships in that higher residential instability, in conjunction with the risk variant of 5-HTTLPR (i.e., the short allele), was associated with the highest level and steepest gradient of growth in substance use across ages 10–24 years. The findings demonstrated how the creation of a harmonized data set increased statistical power to test Gene × Environment interactions for an under studied sample.
It is well known that extracellular signal-regulated kinase 8 (ERK8) plays pivotal roles in various mitotic events. But its physiological roles in oocyte meiotic maturation remain unclear. In this study, we found that although no specific ERK8 signal was detected in oocyte at the germinal vesicle stage, ERK8 began to migrate to the periphery of chromosomes shortly after germinal vesicle breakdown. At prometaphase I, metaphase I (MI), anaphase I, telophase I, and metaphase II (MII) stages, ERK8 was stably detected at the spindles. By taxol treatment, we clarified that the ERK8 signal was stained on the spindle fibers as well as microtubule asters in MI and MII oocytes. In fertilized eggs, the ERK8 signal was not observed in the two pronuclei stages. At prometaphase, metaphase, and anaphase of the first mitosis, ERK8 was detected on the mitotic spindle. ERK8 knock down by antibody microinjection and specific siRNA caused abnormal spindles, failed chromosome congression, and decreased first polar body extrusion. Taken together, our results suggest that ERK8 plays an important role in spindle organization during mouse oocyte meiotic maturation and early embryo cleavage.
The thermoelectric properties of Mg2Si coatings prepared by Atmospheric Plasma Spray (APS), and Vacuum Plasma Spray (VPS) are presented. Seebeck coefficient results of both APS and VPS have been reported. XRD and SEM analysis of the samples are also presented to understand how microstructure influences the coating thermoelectric properties. The results suggest significant improvements can be made on the reduction of impurity including oxidation and pure silicon by using proper spray method and parameters. Thermal spray has been demonstrated before to be effective way to reduce thermal conductivity which may due to the coating microstructure. VPS result shows higher Seebeck coefficient than APS which may due to lower level of oxidization.
In this study, crystal orientation and polymorphism formation in electrospun poly(vinylidene fluoride) (PVDF)/polyacrylonitrile (PAN) blend fibers after melt-recrystallization were studied. To achieve uniform alignment of electrospun fibers, mechanical stretching was applied to the as-spun nonwoven fibers at 110 °C. Pure ferroelectric β-PVDF crystals in the PAN matrix were achieved, and both polar β-PVDF and polar PAN crystals oriented with their chain axes parallel to the fiber axes. After melt-recrystallization of PVDF, a significant amount of ferroelectric β crystals was retained in addition to the formation of nonpolar α crystals. A polarized Fourier transform infrared study showed that the degree of orientation of ferroelectric β-PVDF crystals was higher than that of nonpolar α crystals, suggesting that the β-PVDF crystals should form at the PVDF/PAN interfaces because of strong dipolar and hydrogen bonding interactions between vinylidene fluoride and acrylonitrile units. The nonpolar α-PVDF crystals should form in the center of PVDF domains.
Rare materials recently released by the Zigong City Archives shed light on the accounting system that was created by saltmining businesses in Zigong. The materials include forty-seven accounting books prepared by eight firms in the industry from 1908 to 1930. In this study, the materials are used to reveal how the Zigong salt-mining firms used the double-entry system. The study draws on the archival documents to reveal how the firms' innovative reporting methods enabled them to calculate profit and loss, and it explores the ways in which improved accounting information guided the decisions of Chinese proprietors who were operating in a business environment characterized by inadequate financing, considerable risk, and long intervals between investment and return.
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.
In Northeast China, large volumes of Mesozoic–Cenozoic igneous rocks have developed as a result of long-lasting subduction of the palaeo-Pacific and Pacific plates beneath the eastern Eurasian continent. Previous studies have convincingly confirmed the presence of depleted mantle (DM), FOcal ZOne (FOZO) mantle and enriched mantle 1 (EM1) end-members; the enriched mantle 2 (EM2) end-member is probably present but it has been poorly constrained. The Late Cretaceous Shuangyashan suite, comprising a monzogabbro and diorite–porphyrite stocks and their cumulate hornblendite enclaves, from the Shuangyashan coal basin, Northeast China, is characterized by high initial 87Sr/86Sr (0.70922–0.71095) and low initial 143Nd/144Nd ratios (0.51221–0.51238) at 98 Ma. Their occurrence demonstrates that EM2 is present in the lithospheric mantle of Northeast China and its formation may be related to recycled continental material in a subduction setting.