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The Beijing Twin Study (BeTwiSt), which was established in 2006, is an ongoing study aiming to investigate the genetic and environmental etiology of adolescent psychopathology. Resting-state brain imaging datasets have been examined for same-sex twins, and other psychological traits and emotional and behavioral variables have been examined for all twins. Based on the registry, the main findings regarding the etiological mechanism underlying adolescent development, magnetic resonance imaging results, and genetic and environmental influences on other psychological traits have been published. This article summarizes the key findings in these three areas and discusses future plans for the BeTwiSt.
Asia Minor bluegrass (Polypogon fugax Nees ex Steud.) is a problem grass weed of winter crops in China, where a population has become resistant to aryloxyphenoxypropionate (APP) herbicides. The mechanism of resistance is due to an Ile-2041-Asn mutation of the ACCase gene. Screen house experiments were conducted to study the growth, fecundity characteristics, and competitive ability of this aryloxyphenoxypropionate-resistant (APP-R) biotype compared with a susceptible (APP-S) biotype. When grown under noncompetitive conditions, the APP-R P. fugax developed more rapidly than the APP-S plants, with earlier tiller and panicle emergence and seed shedding; the APP-R P. fugax set seeds nearly 12 d earlier than the APP-S biotype. APP-R and APP-S biotypes had similar aboveground dry weight before the flowering stage. Fecundity of the APP-R biotype was similar to the APP-S biotype (8.57 g seeds plant−1 and 0.17 g seeds panicle−1 versus 8.22 g seeds plant−1 and 0.13 g seeds panicle−1, respectively). Ultimately, the relatively slower-developing APP-S P. fugax had 50% more shoot dry weight than the APP-R plants. Relative competitiveness among the APP-R and APP-S P. fugax biotypes was investigated through replacement series experiments. No difference in competitive ability was measured between APP-R and APP-S biotypes on the basis of shoot dry weight before the tillering stage. These results indicate that there is no apparent fitness penalty for the APP-R P. fugax. The shorter growth cycle of APP-R with no apparent fitness penalty suggests that growers will need begin weed control earlier and possibly include vegetative crops with an even shorter growth cycle in their rotations.
Nano-sized TiN-reinforced Ti metal matrix composites were fabricated by powder metallurgical route, which includes high-energy ball milling pretreatment and subsequent hot-press sintering treatment. The phase composition and microstructure of the sintered samples were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. Results showed that N2 was absorbed and solubilized into TiH2 by milling pretreatment, and TiN was formed during sintering process and was fine to a grain size of 20–100 nm. The final phase composition of the composites was αTi, βTi, and TiN with solution N in matrix. Mechanical tests showed that with increasing milling time, the hardness of the composites increased by 31, 58, 93, and 101% compared with pure Ti. The compressive strength initially increased and later decreased to 2440 and 2120 MPa when milled for 1.5 and 2 h, respectively.
Higher fiber intake reduced all-cause and cardiovascular mortality among healthy population, but such data in dialysis patients are limited. We aimed to examine these associations in patients on peritoneal dialysis. This single-center prospective cohort study enrolled 881 incident PD patients between October 2002 and August 2014. All patients were followed until death, transfer to hemodialysis, renal transplantation or until being censored in June 2018. Demographic data were collected at baseline. Biochemical, dietary, and nutrition data were examined at baseline and thereafter at regular intervals to calculate the average values throughout the study. The outcomes were defined as all-cause and cardiovascular death. Cox proportional regression models were applied to explore the relationship between fiber intake and outcomes. Participants with higher fiber intake were more likely to be younger, male, and having better residual renal function and serum lipids at baseline. They were prone to maintain better nutrient status, higher blood pressure and lower inflammatory status at baseline and afterward. Neither baseline nor time-averaged fiber intake did show protective effects on all-cause mortality after multivariate adjustment in the whole cohort. Among non-diabetic PD patients, an independent association between fiber intake and all-cause mortality was found, in which each 1g/day of increase in time-averaged fiber intake correlated to 13% of reduction in all-cause mortality. We did not observe any benefits of fiber intake in the CVD mortality for both whole cohort and subgroups. This study revealed that higher dietary fiber intake appeared to have a protective effect on all-cause mortality in non-diabetic PD patients, which suggest that PD patients should be encouraged to eat a diet rich in fibers.
Because of its unique mechanical, chemical, and biological properties, 3D-printed polyether ether ketone (PEEK) has great potential as customized bone replacement and other metal alloy implant replacement. PEEK samples were printed using fused deposition modeling (FDM) and evaluated in terms of their dimensional accuracy, crystallinity, and mechanical properties. Crystallinity and mechanical properties increased with elevated chamber temperature and post-printing annealing. Variations of material properties from three printers are evident. Many factors affect the quality of 3D-printed PEEK. Future FDA regulations for 3D-printed products are needed for this highly customizable manufacturing process to ensure safety and effectiveness for biomedical applications.
Crystallization is an extremely important process with extensive industrial applications including, but not limited to, the manufacture of electronics, explosives, fine chemicals, and pharmaceuticals. As such, controlling both crystal shape and crystal structure is vital for the production of high-quality products with desirable properties. However, the processes that govern crystallization, crystal growth, and crystal nucleation are not well understood at present. This is due in part to the limitations of experimental techniques in studying such processes because of the small number of molecules, often tens or hundreds, involved. Furthermore, experimental strategies for identifying and analyzing crystal structures (which may have serious implications in terms of intellectual property rights) and controlling crystal shape are not always successful in yielding the optimal product and often can be costly and time consuming.
Concerns over food safety in China not only direct public attention to negative
incidents, but also trigger the government's scrutiny of implicated
firms, particularly MNCs. The question of how to repair legitimacy after media
coverage of negative incidents has become a critical issue for MNCs. Although
the factors for MNCs’ public crises have been identified, how local
contexts and mechanisms shape repair approaches remain unclear. To address this
research gap, we conducted a study of Walmart China's approaches
associated with two negative incidents across two regions. We found that the
negative incidents can be framed differently depending on the local
environment's unfavorability for MNCs. Specifically, the negative
framing gave rise to varying degrees of legitimacy loss and offered different
leeway for MNCs to repair their legitimacy. We also identified the varied
outcomes of different repair approaches. By revealing the linkages among local
context, framing, legitimacy repair, and its outcomes, our study contributes to
research on MNCs’ legitimacy management under institutional
complexity and underscores the China context for legitimacy maintenance. We also
offer insights that advance the institutional approach to legitimacy repair in
this context. Last, we reflect on the techniques for conducting qualitative
research in China.
Introduction: White matter hyperintensities (WMHs) were commonly seen in brain magnetic resonance imaging (MRI) of the elderly. Many studies found that WMHs were associated with cognitive decline and dementia. However, the association between WMHs in different brain regions and cognitive decline remains debated. Methods: We explored the association of the severity of WMHs and cognitive decline in 115 non-demented elderly (≥50 years old) sampled from the Wuliqiao Community located in urban area of Shanghai. MRI scans were done during 2009–2011 at the beginning of the study. Severity of WMHs in different brain regions was scored by Improved Scheltens Scale and Cholinergic Pathways Hyperintensities Scale (CHIPS). Cognitive function was evaluated by Mini-Mental State Examination (MMSE) every 2 to 4 years during 2009–2018. Results: After adjusting for confounding factors including age, gender, education level, smoking status, alcohol consumption, depression, hypertension, diabetes, hyperlipidemia, brain infarcts, brain atrophy, apoE4 status, and baseline MMSE score, periventricular and subcortical WMH lesions as well as WMHs in cholinergic pathways were significantly associated with annual MMSE decline ( p < 0.05), in which the severity of periventricular WMHs predicted a faster MMSE decline (–0.187 points/year, 95% confidence interval: –0.349, –0.026, p = 0.024). Conclusions: The severity of WMHs at baseline was associated with cognitive decline in the non-demented elderly over time. Interventions on WMH lesions may offer some benefits for cognitive deterioration.
Ceramics are strong but brittle. According to the classical theories, ceramics are brittle mainly because dislocations are suppressed by cracks. Here, the authors report the combined elastic and plastic deformation measurements of nanoceramics, in which dislocation-mediated stiff and ductile behaviors were detected at room temperature. In the synchrotron-based deformation experiments, a marked slope change is observed in the stress–strain relationship of MgAl2O4 nanoceramics at high pressures, indicating that a deformation mechanism shift occurs in the compression and that the nanoceramics sample is elastically stiffer than its bulk counterpart. The bulk-sized MgAl2O4 shows no texturing at pressures up to 37 GPa, which is compatible with the brittle behaviors of ceramics. Surprisingly, substantial texturing is seen in nanoceramic MgAl2O4 at pressures above 4 GPa. The observed stiffening and texturing indicate that dislocation-mediated mechanisms, usually suppressed in bulk-sized ceramics at low temperature, become operative in nanoceramics. This makes nanoceramics stiff and ductile.
Imaging studies have shown that the subcallosal region (SCR) volume was decreased in patients with major depressive disorder (MDD). However, whether the volumetric reductions in the SCR are due to thinning of the cortex or a loss of surface area (SA) remains unclear. In addition, the relationship between cortical measurements of the SCR and age through the adult life span in MDD remains unclear.
We used a cross-sectional design from 114 individuals with MDD and 112 matched healthy control (HC) individuals across the adult life span (range: 18–74 years). The mean cortical volume (CV), SA and cortical thickness (CT) of the SCR were computed using cortical parcellation based on FreeSurfer software. Multivariate analyses of covariance models were performed to compare differences between the MDD and HC groups on cortical measurements of the SCR. Multiple linear regression models were used to test age-by-group interaction effects on these cortical measurements of the SCR.
The MDD had significant reductions in the CV and SA of the left SCR compared with HC individuals after controlling of other variables. The left SCR CV and SA reductions compared with matched controls were observed only in early adulthood patients. We also found a significant age-related CT reduction in the SCR both in the MDD and HC participants.
The SCR volume reduction was mainly driven by SA in MDD. The different trajectories between the CT and SA of the SCR with age may provide valuable information to distinguish pathological processes and normal ageing in MDD.
Muscle fibre types can transform from slow-twitch (slow myosin heavy chain (MyHC)) to fast-twitch (fast MyHC) or vice versa. Leucine plays a vital effect in the development of skeletal muscle. However, the role of leucine in porcine myofibre type transformation and its mechanism are still unclear. In this study, effects of leucine and microRNA-27a (miR-27a) on the transformation of porcine myofibre type were investigated in vitro. We found that leucine increased slow MyHC protein level and decreased fast MyHC protein level, increased the levels of phospho-protein kinase B (Akt)/Akt and phospho-forkhead box 1 (FoxO1)/FoxO1 and decreased the FoxO1 protein level. However, blocking the Akt/FoxO1 signalling pathway by wortmannin attenuated the role of leucine in porcine myofibre type transformation. Over-expression of miR-27a decreased slow MyHC protein level and increased fast MyHC protein level, whereas inhibition of miR-27a had an opposite effect. We also found that expression of miR-27a was down-regulated following leucine treatment. Moreover, over-expression of miR-27a repressed transformation from fast MyHC to slow MyHC caused by leucine, suggesting that miR-27a is interdicted by leucine and then contributes to porcine muscle fibre type transformation. Our finding provided the first evidence that leucine promotes porcine myofibre type transformation from fast MyHC to slow MyHC via the Akt/FoxO1 signalling pathway and miR-27a.
Astrophysical collisionless shocks are amazing phenomena in space and astrophysical plasmas, where supersonic flows generate electromagnetic fields through instabilities and particles can be accelerated to high energy cosmic rays. Until now, understanding these micro-processes is still a challenge despite rich astrophysical observation data have been obtained. Laboratory astrophysics, a new route to study the astrophysics, allows us to investigate them at similar extreme physical conditions in laboratory. Here we will review the recent progress of the collisionless shock experiments performed at SG-II laser facility in China. The evolution of the electrostatic shocks and Weibel-type/filamentation instabilities are observed. Inspired by the configurations of the counter-streaming plasma flows, we also carry out a novel plasma collider to generate energetic neutrons relevant to the astrophysical nuclear reactions.
Dilated Cardiomyopathy is a serious heart disorder that may induce sudden cardiac death and heart failure. Significant progress has been made in understanding the molecular basis of dilated cardiomyopathy. In previous studies, mutations in more than fifty genes have been identified in dilated cardiomyopathy patients. The purpose of this study was to detect the genetic lesion in a family from the central south of China affected by severe dilated cardiomyopathy.
Whole-exome sequencing combined with cardiomyopathy-related genes list were used to analyse the mutations of the proband. Co-segregation analysis was performed by Sanger sequencing.
Results and conclusions
Two novel heterozygous mutations – Myosin Binding Protein C: p.L1014RfsX6 and Titin: p.R9793X – were identified in the proband. The deletion mutation c.3041delT/p.L1014RfsX6 caused a premature stop codon at position 1020 in exon 28 of the Myosin Binding Protein C. The nonsense mutation, c.29377 C>T/ p. R9793X, of Titin was located in the highly evolutionarily conserved domain, resulting in truncation of the Titin protein as well. Co-segregation analysis further revealed that the Myosin Binding Protein C mutation came from his mother and the Titin mutation came from his father. Both mutations are reported in dilated cardiomyopathy patients for the first time. Our study not only provides a unique example of the genes and molecular mechanisms involved in dilated cardiomyopathy but also expands the spectrum of Myosin Binding Protein C and Titin mutations and contributes to the genetic diagnosis and counselling of dilated cardiomyopathy patients.
Drag control using a newly developed spanwise opposed wall-jet forcing (SOJF) method is studied via direct numerical simulation of the incompressible Navier–Stokes equations in a turbulent channel flow (at the friction Reynolds numbers
and 550). SOJF is characterized by three control parameters: the forcing amplitude
, the spanwise spacing
and the wall-jet height
indicates viscous scaling). At
, notable drag reduction is achieved for wide ranges of
, with an optimal drag reduction of approximately 19 % found for
. The drag reduction results from mergers of numerous low-speed typical individual streaks together by the wall jets, so that the slope of the merged streak envelope and hence the streak strength are reduced below the critical values required for streak instability as well as for transient growth; consequently, the generation of drag inducing near-wall streamwise vortices is suppressed. Through analysis using the FIK identity (Fukagata et al.Phys. Fluids, vol. 14 (11), 2002, pp. L73–L76) in combination with the triple decomposition and the spanwise wavenumber spectrum of the Reynolds shear stress, we find that the control significantly decreases skin friction due to the small scale random turbulent structures (from 75 to 23 % for the optimal case), but injects a dominant contribution at the forcing scale (approximately 34 %). As
increases, the drag reduction degrades due to the downwash near the initiation of the forcing wall jet. The energy input required for the excitation is found to be small, yielding a 17 % net power saving for the optimal control case. To determine the
dependence of the drag reduction, the control strategy is further validated at a higher
. If the control parameters are kept the same as at
), the drag reduction decreases to 10 %; however, interestingly, with modestly changed parameters (
), drag reduction increases to about 15 %. This additional drag reduction results from the further suppression of turbulent structures in the buffer and log regions. This result, therefore, suggests prospects for drag reduction at even higher
via a proper choice of the SOJF parameters.
As a promising new way to generate a controllable strong magnetic field, laser-driven magnetic coils have attracted interest in many research fields. In 2013, a kilotesla level magnetic field was achieved at the Gekko XII laser facility with a capacitor–coil target. A similar approach has been adopted in a number of laboratories, with a variety of targets of different shapes. The peak strength of the magnetic field varies from a few tesla to kilotesla, with different spatio-temporal ranges. The differences are determined by the target geometry and the parameters of the incident laser. Here we present a review of the results of recent experimental studies of laser-driven magnetic field generation, as well as a discussion of the diagnostic techniques required for such rapidly changing magnetic fields. As an extension of the magnetic field generation, some applications are discussed.
A systematic investigation of influence of the laser hatch style on densification behavior, microstructure, and tribological performance of aluminum parts’ preparation by selective laser melting (SLM) was implemented in this study. The scans with checker board (CB) style left better processing quality of surface morphology and few metallurgical defects to SLM parts in comparison with single fill and cross fill styles, hence leading to a relatively high densification level (99.42%). The CB style of shorter scan length left higher undercooling degree in small checker areas compared with other longer scan lengths, leading to finer equiaxed grains to the solidification microstructure. Accordingly, an enhanced mean microhardness of 129.7 HV0.1 was obtained in this hatch style, due to the grain refinement strengthening effect. The lowest coefficient of friction of 0.49 and wear rate of 2.43 × 10−4 mm3/(N m) were obtained. The improved densification level and formation of refined equiaxed grain and evenly distributed ring-shaped Si particles formed in CB parts changed the mechanism of material removal during sliding from the abrasion to adhesion of the tribolayer, significantly improving the wear resistance of SLM aluminum parts.
We present laboratory measurement and theoretical analysis of silicon K-shell lines in plasmas produced by Shenguang II laser facility, and discuss the application of line ratios to diagnose the electron density and temperature of laser plasmas. Two types of shots were carried out to interpret silicon plasma spectra under two conditions, and the spectra from 6.6 Å to 6.85 Å were measured. The radiative-collisional code based on the flexible atomic code (RCF) is used to identify the lines, and it also well simulates the experimental spectra. Satellite lines, which are populated by dielectron capture and large radiative decay rate, influence the spectrum profile significantly. Because of the blending of lines, the traditional
value are not applicable in diagnosing electron temperature and density of plasma. We take the contribution of satellite lines into the calculation of line ratios of He-
lines, and discuss their relations with the electron temperature and density.
An intelligent decision-making method was proposed for airport bird-repelling based on a Support Vector Machine (SVM) and bird-strike risk assessment. The bird-strike risk assessment model is established with two exponential functions to separate the risk levels, while the SVM method includes two steps of training and testing. After the risk assessment, the Bird-Repelling Strategy Classification Model (BRSCM) was trained based on the expert knowledge and large amount of historical bird information collected by the airport linkage system for bird detection, surveillance and repelling. Then, in the testing step, the BRSCM was continuously optimised according to the real-time intelligent bird-repelling strategy results. Through several bird-repelling examples of a certain airport, it is demonstrated that the decision accuracy of BRSCM is relatively high, and it could solve new problems by self-correction. The proposed method achieved the optimised operation of multiple bird-repelling devices against real-time bird information with great improvement of bird-repelling effects, overcoming the tolerance of birds to the bird-repelling devices due to their long-term repeated operation.