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.
Metabolically healthy obesity refers to a subset of obese people with a normal metabolic profile. We aimed to explore the association between metabolically healthy and obesity status and risk of hypertension among Chinese adults from The Rural Chinese Cohort Study. This prospective cohort study enrolled 9137 Chinese adults without hypertension, type 2 diabetes or treatment for lipid abnormality at baseline (2007–2008) and followed up during 2013–2014. Modified Poisson regression models were used to examine the risk of hypertension by different metabolically healthy and obesity status, estimating relative risks (RR) and 95 % CI. During 6 years of follow-up, we identified 1734 new hypertension cases (721 men). After adjusting for age, sex, smoking and other confounding factors, risk of hypertension was increased with metabolically healthy general obesity (MHGO) defined by BMI (RR 1·75, 95 % CI 1·02, 3·00) and metabolically healthy abdominal obesity (MHAO) defined by waist circumference (RR 1·51, 95 % CI 1·12, 2·04) as compared with metabolically healthy non-obesity. The associations between metabolically healthy and obesity status and hypertension outcome were consistent after stratifying by sex, age, smoking, alcohol drinking and physical activity. Both MHGO and MHAO were associated with increased risk of hypertension. Obesity control programmes should be implemented to prevent or delay the development of hypertension in rural China.
In the era of knowledge networking, the structure and production mode of knowledge are constantly changing. This article creatively introduces the knowledge mapping method in design research, and based on the perspective of the National Natural Science Foundation of China (NSFC) to compile literature, uses word frequency analysis, co-word analysis, and citation analysis to construct knowledge graphs of design science. This study graphically shows the distribution and flow law of knowledge within design discipline and probes into the research frontier and evolution trend of Chinese design science.
A kind of novel Ni–P gradient coating/stannate conversion film was deposited on AZ91D magnesium alloy (AZ91D alloy) by an integrative method involved stannate conversion and electroless plating. The results indicated that using sodium hypophosphite concentrations varied as 5, 10, 22, 46, and 60 g/L in the bath, the electroless Ni–P gradient coating with typical cell morphologies was successfully prepared, and the structures transited from crystalline → microcrystalline → amorphous were obtained as increasing P content from 3.31 to 12.58 wt%. Furthermore, the corrosion morphologies, polarization curves, and the electrochemical impedance spectroscopy result indicated that the corrosion resistance of AZ91D alloy substrate was significantly improved and the corrosion resistance of Ni–P gradient coating was superior than that of stannate conversion film, which might be attributed to the gradient structure and rising P content with unique function.
Mastery of strengthening strategies to achieve high-capacity anodes for lithium-ion batteries can shed light on understanding the nature of diffusion-induced stress and offer an approach to use submicro-sized materials with an ultrahigh capacity for large-scale batteries. Here, we report solute strengthening in a series of silicon (Si)–germanium (Ge) alloys. When the larger solute atom (Ge) is added to the solvent atoms (Si), a compressive stress is generated in the vicinity of Ge atoms. This local stress field interacts with resident dislocations and subsequently impedes their motion to increase the yield stress in the alloys. The addition of Ge into Si substantially improves the capacity retention, particularly in Si0.50Ge0.50, aligning with literature reports that the Si/Ge alloy showed a maximum yield stress in Si0.50Ge0.50. In situ X-ray diffraction studies on the Si0.50Ge0.50 electrode show that the phase change undergoes three subsequent steps during the lithiation process: removal of surface oxide layer, formation of cluster-size Lix(Si,Ge), and formation of crystalline Li15(Si,Ge)4. Furthermore, the lithiation process starts from higher index facets, i.e., (220) and (311), then through the low index facet (111), suggesting the orientation-dependence of the lithiation process in the Si0.50Ge0.50 electrode.
An invariant measure is called a Bernoulli measure if the corresponding dynamics is isomorphic to a Bernoulli shift. We prove that for
diffeomorphisms any weak mixing hyperbolic measure could be approximated by Bernoulli measures. This also holds true for
diffeomorphisms preserving a weak mixing hyperbolic measure with respect to which the Oseledets decomposition is dominated.
The Safety Level Approach (SLA) is a structured application of risk-based methodologies for the International Maritime Organization's (IMO's) rule-making process. When the SLA is applied, safety goals have to be provided. In order to set appropriate levels for safety goals, it is necessary to measure the tolerance degree of the current safety level. Based on the consistency with individual risk criteria and the principle of continuous improvement, this paper proposes an approach to establish the societal risk criteria, which can be used for setting safety goals in the context of the IMO's SLA. Furthermore, by defining dynamic factors to express risk aversion, a method for tolerance measurement of the current societal risk is developed. Finally, a case study into the societal risk evaluation of cruise ships and Roll-On Roll-Off (RO-RO) passenger ships is conducted.
The shear-band propagation in bulk metallic glasses (BMGs) during deformation plays a key role in determining their macroscopic ductility. In this work, the shear band propagation during plastic deformation was investigated in the Cu46Zr46Al8 BMG and its in situ or ex situ prepared BMG composites. Compared with the brittle BMG, both types of ductile BMG composites show a more stable shear banding behavior as revealed by a larger power-law scaling exponent obtained from statistical analysis of serrations recorded in compressive curves. A higher cut-off elastic energy density (δc) linked with the multiplication of shear bands is observed for the in situ prepared BMG composites. However, the ex situ fabricated BMG composites show an almost equivalent or slightly larger δc since the dominant shear band but not multiple shear bands mainly governs their deformation. Such observations imply that the shear banding stability of BMGs during deformation is enhanced not only by inducing multiple shear bands but also by obstructing the movement of the dominant shear band at its driven path.
The Al–50Si alloy, as a kind of potential electronic packaging material, is manufactured by different methods, such as casting and spray deposition. The possible influences of the P refiner on the microstructure of the Al–50Si alloy are investigated at different cooling rates. The refinement mechanism of primary Si phase is discussed in view of the P refiner addition, and the variation of the cooling rates. The thermal conductivity (TC), as a key parameter for electronic materials, is measured. The coupled effects of the cooling rate and the addition of the P refiner during the solidification of the Al–50Si alloy on the TC are elucidated based on structural observations. Furthermore, the porosity in the Al–50Si alloy is treated as a second phase influencing the TC.
Correlative light and electron microscopy (CLEM) offers a means of guiding the search for the unique or rare events by fluorescence microscopy (FM) and allows electron microscopy (EM) to zoom in on them for subsequent EM examination in three-dimensions (3D) and with nanometer-scale resolution. FM visualizes the localization of specific antigens by using fluorescent tags or proteins in a large field-of-view to study their cellular function, whereas EM provides the high level of resolution for complex structures. And cryo CLEM combines the advantages of maintaining structural preservation in a near-native state throughout the entire imaging process and by avoiding potentially harmful pre-treatments, such as chemical fixation, dehydration and staining with heavy metals. Besides for frozen-hydrated biological samples, CLEM combines the advantages of a close-to-life preservation of biological materials by keeping them embedded in vitreous ice throughout the entire imaging process and the frozen-hydrated condition is very suitable to maintain fluorescent signals. In recent years, many new instruments and software which intended to optimize the workflow and to obtain better experimental results of CLEM have been presented or even commoditized. While, the specimen damage during transfer from FM to EM and the resolution of CLEM were still need to be improved.
Here we set up a High-vacuum Optical Platform to develop CLEM imaging technology (HOPE), which was designed to realize high-vacuum optical ( fluorescent) imaging for cryo-sample on EM cryo-holder (e.g. Gatan 626). A non-integrated high-vacuum cryo-optical stage, which adapted to the EM cryo holder, was fixed on epi-fluorescence microscope (or super-resolution microscope) to obtain fluorescent images. And then the EM cryo holder would be transferred to EM for collection of EM data. This protocol was aimed to minimize the specimen damage during transfer from FM to EM and it was versatile to expend to different types of light microscopy or electron microscopy. Our HOPE had already passed correlative imaging test, and the results showed that it was convenient and effective.
To investigate the potential influence of dietary Se intake on mortality among Chinese populations.
We prospectively evaluated all-cause, CVD and cancer mortality risks associated with dietary Se intake in participants of the Shanghai Women’s Health Study (SWHS) and the Shanghai Men’s Health study (SMHS). Dietary Se intake was assessed by validated FFQ during in-person interviews. Cox proportional hazards models were used to calculate hazard ratios (HR) and 95 % CI.
Urban city in China.
Chinese adults (n 133 957).
During an average follow-up of 13·90 years in the SWHS and 8·37 years in the SMHS, 5749 women and 4217 men died. The mean estimated dietary Se intake was 45·48 μg/d for women and 51·34 μg/d for men, respectively. Dietary Se intake was inversely associated with all-cause mortality and CVD mortality in both women and men, with respective HR for the highest compared with the lowest quintile being 0·79 (95 % CI 0·71, 0·88; Ptrend<0·0001) and 0·80 (95 % CI 0·66, 0·98; Ptrend=0·0268) for women, and 0·79 (95 % CI 0·70, 0·89; Ptrend=0·0001) and 0·66 (95 % CI 0·54, 0·82; Ptrend=0·0002) for men. No significant associations were observed for cancer mortality in both women and men. Results were similar in subgroup and sensitivity analyses.
Dietary Se intake was inversely associated with all-cause and cardiovascular mortality in both sexes, but not cancer mortality.
Crack propagation behaviors in a precracked single crystal Ag under mode I loading at different temperatures are studied by molecular dynamics simulation. The simulation results show that the crack propagation behaviors are sensitive to external temperature. At 0 K, the crack propagates in a brittle manner. Crack tip blunting and void generation are first observed followed by void growth and linkage with the main crack, which lead to the propagation of the main crack and brittle failure immediately without any microstructure evolution. As the temperature gets higher, more void nucleations and dislocation emissions occur in the crack propagation process. The deformation of the single crystal Ag can be considered as plastic deformation due to dislocation emissions. The crack propagation dynamics characterizing the microstructure evolution of atoms around the crack tip is also shown. Finally, it is shown that the stress of the single crystal Ag changes with the crack length synchronously.
A defect in the intestinal barrier is one of the characteristics of Crohn's disease (CD). The tight junction (TJ) changes and death of epithelial cells caused by intestinal inflammation play an important role in the development of CD. DHA, a long-chain PUFA, has been shown to be helpful in treating inflammatory bowel disease in experimental models by inhibiting the NF-κB pathway. The present study aimed at investigating the specific effect of DHA on the intestinal barrier function in IL-10-deficient mice. IL-10-deficient mice (IL-10− / −) at 16 weeks of age with established colitis were treated with DHA (i.g. 35·5 mg/kg per d) for 2 weeks. The severity of their colitis, levels of pro-inflammatory cytokines, epithelial gene expression, the distributions of TJ proteins (occludin and zona occludens (ZO)-1), and epithelial apoptosis in the proximal colon were measured at the end of the experiment. DHA treatment attenuated the established colitis and was associated with reduced infiltration of inflammatory cells in the colonic mucosa, lower mean histological scores and decreased levels of pro-inflammatory cytokines (IL-17, TNF-α and interferon-γ). Moreover, enhanced barrier function was observed in the DHA-treated mice that resulted from attenuated colonic permeability, rescued expression and corrected distributions of occludin and ZO-1. The results of the present study indicate that DHA therapy may ameliorate experimental colitis in IL-10− / − mice by improving the intestinal epithelial barrier function.
Equations based on simple anthropometric measurements to predict body fat percentage (BF%) are lacking in Chinese population with increasing prevalence of obesity and related abnormalities. We aimed to develop and validate BF% equations in two independent population-based samples of Chinese men and women. The equations were developed among 960 Chinese Hans living in Shanghai (age 46·2 (sd 5·3) years; 36·7 % male) using a stepwise linear regression and were subsequently validated in 1150 Shanghai residents (58·7 (sd 6·0) years; 41·7 % male; 99 % Chinese Hans, 1 % Chinese minorities). The associations of equation-derived BF% with changes of 6-year cardiometabolic outcomes and incident type 2 diabetes (T2D) were evaluated in a sub-cohort of 780 Chinese, compared with BF% measured by dual-energy X-ray absorptiometry (DXA; BF%-DXA). Sex-specific equations were established with age, BMI and waist circumference as independent variables. The BF% calculated using new sex-specific equations (BF%-CSS) were in reasonable agreement with BF%-DXA (mean difference: 0·08 (2 sd 6·64) %, P= 0·606 in men; 0·45 (2 sd 6·88) %, P< 0·001 in women). In multivariate-adjusted models, the BF%-CSS and BF%-DXA showed comparable associations with 6-year changes in TAG, HDL-cholesterol, diastolic blood pressure, C-reactive protein and uric acid (P for comparisons ≥ 0·05). Meanwhile, the BF%-CSS and BF%-DXA had comparable areas under the receiver operating characteristic curves for associations with incident T2D (men P= 0·327; women P= 0·159). The BF% equations might be used as surrogates for DXA to estimate BF% among adult Chinese. More studies are needed to evaluate the application of our equations in different populations.
The aim of the present study was to investigate the prevalence of hyperhomocysteinaemia (HHCY; total plasma homocysteine (tHcy) concentration >15 μmol/l) and its major determinants in healthy Chinese northerners. A descriptive and cross-sectional study was conducted in Shaanxi Province, China. The study sample included 2645 participants (1042 men and 1603 women) aged >20 years. Demographic characteristics and lifestyle factors were assessed via questionnaire interviews and physical examination. Plasma levels of homocysteine and folate and methylenetetrahydrofolate reductase (MTHFR) gene polymorphism were determined according to standard methods. The prevalence of HHCY was 67·7 % (81·4 % in men and 58·8 % in women). The geometric mean of tHcy concentration was 19·1 μmol/l. The OR of HHCY were 0·44 (95 % CI 0·34, 0·57) for women v. men; 1·95 (95 % CI 1·41, 2·70), 1·41 (95 % CI 1·05, 1·88) and 0·76 (95 % CI 0·64, 0·89) for participants with smoking and alcohol drinking cessation and improved physical activity levels, respectively; 0·25 (95 % CI 0·17, 0·38), 0·33 (95 % CI 0·22, 0·49) and 0·56 (95 % CI 0·36, 0·88) for participants with an education level of elementary school, secondary school and university v. illiterate, respectively; 1·41 (95 % CI 1·13, 1·75) and 3·05 (95 % CI 2·35, 3·97) for participants with CT and TT v. CC genotype at MTHFR 677C → T polymorphism, respectively. These results demonstrate that the prevalence of HHCY is considerably high in Chinese northerners, especially in TT subjects, suggesting that implementation of tHcy-lowering strategies, such as lifestyle changes, is necessary.
The depositional history of the lower Yangtze River and sea-level changes during Marine Oxygen Isotope Stage (MIS) 3 was established using three long drill cores from the northern Yangtze deltaic plain and southern Yellow Sea by using sedimentary analysis and AMS 14C dates. Voluminous channel deposits of the lower Yangtze River in MIS 3 were found from the northern deltaic plain and offshore area, with a thickness of over 30 m. The thick channel deposits are characterized by massive medium-to-fine sand deposits with sporadic tidal influence. During MIS 3, the Yangtze River appears to have mainly migrated between the modern river mouth and middle Jiangsu coastal plain, and likely built a delta complex in the field of Yangtze Sand Shoal in northern East China Sea. A large sediment supply and rapid sea-level variations promoted rapid progradation of the delta onto the flat shelf. The highest sea levels during MIS 3 are estimated to have reached 25 ± 5 m below the present sea level.
We present a concept of robust optimisation design for the spring actuator in a 10 kV/12.5 kA vacuum circuit breaker. We assume the breaking and closing velocity characteristics, which are derived form the technical data of the interrupter, as the specifications for the problem, and take the lengths of the connecting rods of the actuator and the stiffness coefficients of the breaking and closing springs as the optimisation variables. The variance between the specifications and the velocities calculated at each breaking and closing point and the maximal variation allowed by the design variables within acceptable tolerances make up the multiple objective function. The optimal parameters for the spring actuator are given by solving a non-linear programming problem with multiple targets and two-level optimisation.
This paper proposes a novel parallel manipulator with 1 translational and 3 rotational degrees of freedom, which may be designed as the docking equipment for large-scale component assemblage in the aircraft industry. First, the mobility and kinematic analysis of the novel manipulator is performed using the screw theory and the closed-loop vector method. To evaluate the kinematic performance of the manipulator, its workspace is calculated, and the dimensional homogeneous Jacobian matrix of this manipulator is deduced. Mainly based on a nonlinear programming approach, the kinematic dimensional synthesis is performed to optimise the dimensional parameters of this novel parallel manipulator in a prescribed workspace. The results of this paper may lay a solid foundation for the prototype design and manufacture of the novel parallel manipulator.
This study mainly focused on the key technologies, the photon dose calculation based on the Monte Carlo Finite-Size Pencil Beam (MCFSPB) model in the Accurate Radiotherapy System (ARTS). In the MCFSPB model, the acquisition of pencil beam kernel is one of the most important technologies. In this study, by analyzing the demerits of the clinical pencil beam dose calculation methods, a new pencil beam kernel model was developed based on the Monte Carlo (MC) simulation and the technology of medical accelerator energy spectrum reconstruction. which greatly improved the accuracy of calculated result. According to the axial symmetry principle, only part of simulation results was used for the data of pencil beam kernel, which greatly reduced the data quantity of the pencil beam and reduced calculated time. Based on the above studies, the MCFSPB method was designed and implemented by the Visual C++ development tool. With several tests including the comparisons among the American Association of Physicists in Medicine (AAPM) No. 55 Report sample and the ion chamber measurement of lung-simulating inhomogeneous phantom in clinical treatment plan, the results showed that the maximum error of most calculated point was less than 0.5% in the homogeneous phantom and less than 3% in the heterogeneous phantom. This method met the clinical criteria, and would be expected to be used as a fast and accurate dose engine for clinic TPS.
In this study, C57BL/6 adult male mouse ear fibroblast cells and Kunming mouse M2 oocytes were used as donors and recipients, respectively, to investigate the effect of passage number on donor cells and electrofusion times on the in vitro development of nuclear transfer (NT) embryos. The results demonstrated firstly that when the ear fibroblast cells from either 2–4, 5–7 or 8–10 passages were used as donors, respectively, to produce NT embryos, the number of passages undergone by the donor cells had no significant effect on the in vitro development of NT embryos. The developmental rates for morula/blastocyst were 15.2, 13.3 and 14.0%, respectively, which were not significantly difference (p > 0.05). Secondly, when the NT embryos were electrofused, there was no significant difference between the fusion ratio for the first electrofusion and the second electrofusion (p > 0.05). The developmental rates of the 2-cell and 4-cell stages that had undergone only one electrofusion, however, were significantly higher than those that had had two electrofusions (65.7% compared with 18.4% and 36.4% compared with 6.1%; p < 0.01), furthermore the NT embryos with two electrofusions could not develop beyond the 4-cell stage. This study suggests that this protocol might be an alternative method for mouse somatic cloning, even though electrofusion can exert negative effects on the development of NT embryos.