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Employing atomic-scale simulations, the response of a high-angle grain boundary (GB), the soft/hard GB, against external loading was systematically investigated. Under tensile loading close to the hard orientation, strain-induced dynamic recrystallization was observed to initiate through direct soft-to-hard grain reorientation, which was triggered by stress mismatch, inhibited by surface tension from the soft-hard GB, and proceeded by interface ledges. Such grain reorientation corresponds with expansion and contraction of the hard grain along and perpendicular to the loading direction, respectively, accompanied by local atomic shuffling, providing relatively large normal strain of 8.3% with activation energy of 0.04 eV per atom. Tensile strain and residual dislocations on the hard/soft GB facilitate the initiation of dynamic recrystallization by lowering the energy barrier and the critical stress for grain reorientation, respectively.
Brain structural connectome comprise of a minority of efficiently interconnected rich club nodes that are regarded as ‘high-order regions’. The remission of major depressive disorder (MDD) in response to selective serotonin reuptake inhibitor (SSRI) treatment could be investigated by the hierarchical structural connectomes’ alterations of subnetworks.
Fifty-five MDD patients who achieved remission underwent diffusion tensors imaging (DTI) scanning from 3 cohorts before and after 8-weeks antidepressant treatment. Five hierarchical subnetworks namely, rich, local, feeder, rich-feeder and feeder-local, were constructed according to the different combinations of connections and nodes as defined by rich club architecture. The critical treatment-related subnetwork pattern was explored by multivariate pattern analysis with support vector machine to differ the pre-/post-treatment patients. Then, relationships between graph metrics of discriminative subnetworks/ nodes and clinical variables were further explored.
The feeder-local subnetwork presented the most discriminative power in differing pre-/post- treatment patients, while the rich-feeder subnetwork had the highest discriminative power when comparing pre-treatment patients and controls. Furthermore, based on the feeder connection, which indicates the information transmission between the core and non-core architectures of brain networks, its topological measures were found to be significantly correlated with the reduction rate of 17-item Hamilton Rating Scale for Depression.
Although pathological lesion on MDD relied on abnormal core organization, disease remission was association with the compensation from non-core organization. These results suggested that the dysfunctions arising from hierarchical subnetworks are compensated by increased information interactions between core brain regions and functionally diverse regions.
Chickenpox is a common acute and highly contagious disease in childhood; moreover, there is currently no targeted treatment. Carrying out an early warning on chickenpox plays an important role in taking targeted measures in advance as well as preventing the outbreak of the disease. In recent years, the infectious disease dynamic model has been widely used in the research of various infectious diseases. The logistic differential equation model can well demonstrate the epidemic characteristics of epidemic outbreaks, gives the point at which the early epidemic rate changes from slow to fast. Therefore, our study aims to use the logistic differential equation model to explore the epidemic characteristics and early-warning time of varicella. Meanwhile, the data of varicella cases were collected from first week of 2008 to 52nd week of 2017 in Changsha. Finally, our study found that the logistic model can be well fitted with varicella data, besides the model illustrated that there are two peaks of varicella at each year in Changsha City. One is the peak in summer–autumn corresponding to the 8th–38th week; the other is in winter–spring corresponding to the time from the 38th to the seventh week next year. The ‘epidemic acceleration week’ average value of summer–autumn and winter–spring are about the 16th week (ranging from the 15th to 17th week) and 45th week (ranging from the 44th to 47th week), respectively. What is more, taking warning measures during the acceleration week, the preventive effect will be delayed; thus, we recommend intervene during recommended warning weeks which are the 15th and 44th weeks instead.
S-layer proteins of various lattice-forming types are the most abundant protein by mass on earth. They form the outermost cell crystalline component in a broad range of bacteria and archaea. They are porous monomolecular layer with unit cell size in tens of nanometers. These monomer proteins are capable of forming self-assembled mono- or double layers. Isolated from cell surfaces or through recombinant protein production, they are able to form ordered 2D crystal lattice on a variety of non-cellular surfaces. We study S-layer SbpA protein, which is found in mesophilic organism Lysinibacillus sphaericus with square lattice crystallinity. The recombinant SbpA (rSbpA) can be genetically modified and expressed in E. coli in different truncated forms. Using both the wtSpbA and truncated rSbpA, we reproduced the unique two-dimensional self-assembly pattern on several solid or flexible surfaces of interests towards electronic devices. By surface modification we can promote the self-assembly of SbpA on low affinity substrates. This enables a potential mean of creating complex functional bio-nanostructure. Delicate control of the self-assembly processes of S-layer on surfaces also serves the prerequisite of building the supramolecular structure as bio-electronic platform through protein fusing. Understanding of the electrical response from s-layer proteins provides a bridge between biological systems and electronic devices. Scale-up production and understanding the detailed interaction of the S-layer interface will likely be useful for nanobiotechnology and synthetic biology.
The acquisition and tracking strategies of the BeiDou navigation satellite signals are affected by the modulation of Neumann-Hoffman code (NH code), which increases the complexity of receiver baseband signal processing. Based on the analysis of probability statistics of the NH code, a special sequence of incoming signals is proposed to evade the bit transitions caused by the NH code, and an NH Code Evasion and Stripping method (NCES) based on the NH-pre-modulated code is proposed. The NCES can be applied in both 20-bit NH code and 10-bit NH code. The fine acquisition eliminates the impact of NH code on the traditional tracking loop. These methods were verified with a BeiDou PC-based software-defined receiver using the actual sampled signals. Compared with other acquisition schemes which try to determine or ignore the NH code phase, the NCES needs fewer incoming signals and the actual runtime is greatly reduced without sacrificing much time to search in the secondary code dimension, and the success rate of acquisition is effectively improved. An extension of Fast Fourier Transform (FFT)-based parallel code-phase search acquisition gives the NCES an advantage in engineering applications.
The Lorentz factor (Γ) is an important parameter related to the relativistic jet physics. We study the evolution patterns of Γ within gamma-ray burst (GRB) and active galactic nuclear jets for individual GRB 090168, GRB 140508A, and 3C 454.3. By estimating the Γ values for well-separated pulses in GRBs 090618 and 140508A with an empirical relation derived from typical GRBs, we find that the Γ evolution pattern in the two GRBs are different. The increasing-to-coasting evolution pattern of Γ in GRB 090618 likely indicates that the GRB fireball is still being accelerated in the prompt phase. The clear decrease evolution pattern of Γ in GRB 140508A suggests the deceleration of the fireball components. By deriving the Γ value through fitting their spectral energy distribution in different flares of 3C 454.3, a pattern of Γ-tracking-γ-ray flux is clearly found, likely indicating that the observed gamma-ray flares are being due to the Doppler boosting effect to the jet emission.
We present experimental evidence that a minute amount of polymer additives can significantly enhance heat transport in the bulk region of turbulent thermal convection. The effects of polymer additives are found to be the enhancement of coherent heat fluxes and suppression of incoherent heat fluxes. The enhanced heat transport is associated with the increased coherency of thermal plumes, as a result of the suppression of small-scale turbulent fluctuations by polymers. The incoherent heat flux, arising from turbulent background fluctuations, makes no net contribution to heat transport. The fact that polymer additives can increase the coherency of thermal plumes is supported by the measurements of a number of local quantities, such as the extracted plume amplitude and width, the velocity autocorrelation functions and the velocity–temperature cross-correlation coefficient. The results from local measurements also suggest the existence of a threshold value for the polymer concentration, only above which significant modification of the plume coherent properties and enhancement of the local heat flux can be observed. Estimation of the plume emission rate suggests a stabilization of the thermal boundary layer by polymer additives.
We report an experimental study of the large-scale circulation (LSC) reversal in quasi-2D turbulent thermal convection, in which the aspect ratio
of a rectangular box) is used as a parameter to perturb the stability of the LSC. It is found that the mean time interval
between two successive reversals increases strongly with increasing
. A stochastic model is proposed to incorporate the effect of the corner rolls. In the model, the aspect ratio serves as a tuning parameter for the relative weight of the corner rolls that damp the LSC. The model predictions for the shape of the bistable states of the system and
agree excellently with the experimental results, with
having an unexpected stretched exponential Rayleigh number dependence,
. We further show quantitatively that the main damping force of the LSC in a quasi-2D system is from the corner rolls rather than the viscous drag from the sidewalls, which bridges the difference found in quasi-2D and 3D systems.
Few studies have explored the relationship between dietary patterns and the risk of gestational diabetes mellitus (GDM). Evidence from non-Western areas is particularly lacking. In the present study, we aimed to examine the associations between dietary patterns and the risk of GDM in a Chinese population. A total of 3063 pregnant Chinese women from an ongoing prospective cohort study were included. Data on dietary intake were collected using a FFQ at 24–27 weeks of gestation. GDM was diagnosed using a 75 g, 2 h oral glucose tolerance test. Dietary patterns were determined by principal components factor analysis. A log-binomial regression model was used to examine the associations between dietary pattern and the risk of GDM. The analysis identified four dietary patterns: vegetable pattern; protein-rich pattern; prudent pattern; sweets and seafood pattern. Multivariate analysis showed that the highest tertile of the vegetable pattern was associated with a decreased risk of GDM (relative risk (RR) 0·79, 95 % CI 0·64, 0·97), compared with the lowest tertile, whereas the highest tertile of the sweets and seafood pattern was associated with an increased risk of GDM (RR 1·23, 95 % CI 1·02, 1·49). No significant association was found for either the protein-rich or the prudent pattern. The protective effect of a high vegetable pattern score was more evident among women who had a family history of diabetes (P for interaction = 0·022). These findings suggest that the vegetable pattern was associated with a decreased risk of GDM, while the sweets and seafood pattern was associated with an increased risk of GDM. These findings may be useful in dietary counselling during pregnancy.
We present an experimental study of turbulent thermal convection with smooth and rough surface plates in various combinations. A total of five cells were used in the experiments. Both the global
for each plate (or the associated boundary layer) are measured. The results reveal that the smooth plates are insensitive to the surface (rough or smooth) and boundary conditions (i.e. nominally constant temperature or constant flux) of the other plate of the same cell. The heat transport properties of the rough plates, on the other hand, depend not only on the nature of the plate at the opposite side of the cell, but also on the boundary condition of that plate. It thus appears that, at the present level of experimental resolution, the smooth plate can influence the rough plate, but cannot be influenced by either the rough or the smooth plates. It is further found that the scaling of
for all of the smooth plates is consistent with the classical
exponent. But the scaling exponent for the global
for the cell with both plates being smooth is definitely less than
(this result itself is consistent with all previous studies at comparable parameter range). The discrepancy between the
behaviour at the whole-cell and individual-plate levels is not understood and deserves further investigation.
As one of the highly diversified radiolarian groups in the Mesozoic, Vallupinae occurred widely in the tuffaceous claystone from the Mariana Trench of the upper Tithonian–Berriasian where the specimens are extremely well-preserved. The occurrence of diversified Vallupinae presented here is further evidence that the range of Vallupinae extends to Berriasian. The stratigraphic range and proposed possible phylogenetic relationships within the Subfamily Vallupinae are provided and 17 radiolarian species of this subfamily are presented, including three new species: Vallupus gracilis, Mesovallupus brevispina, and Neovallupus mediforma.
The ability of silver (Ag)-containing borate bioactive glass (BG) coatings to improve the biocompatibility and antibacterial properties of titanium (Ti) implants was investigated in vitro and in vivo in a rabbit tibial fracture model. Dense coatings of borate BG (thickness ≈ 20 μm) containing 0, 0.75, and 1.0 wt% Ag2O were prepared by depositing a layer of particles on Ti plates, followed by sintering at 900 °C. The as-prepared coatings had an adhesive strength of 10 ± 1 MPa, and when immersed in an aqueous phosphate (K2HPO4) solution, the coatings converted to hydroxyapatite, releasing Ag+ ions continuously for over 4 wk. After implantation of BG-coated Ti constructs in a rabbit tibial fracture model and of methicillin-resistant Staphylococcus aureus-induced osteomyelitis, the BG coating doped with 1.0 wt% Ag2O was most effective for the simultaneous eradication of the infection and fracture fixation. Implants coated with Ag-containing BG coatings could provide an approach for reducing implant-related bone infection.
We report the first experimental study of Lagrangian acceleration in turbulent Rayleigh–Bénard convection, using particle tracking velocimetry. A method has been developed to quantitatively evaluate and eliminate the uncertainties induced by temperature and refraction index fluctuations caused by the thermal plumes. It is found that the acceleration p.d.f. exhibits a stretched exponential form and that the probability for large magnitude of acceleration in the lateral direction is higher than those in the vertical directions, which can be attributed to the vortical motion of the thermal plumes. The local acceleration variance was obtained for various values of the three control parameters: the Rayleigh number (), the Prandtl number ( and 6.1) and the system size . These were then compared with the theoretically predicted dependence on these parameters for buoyancy-dominated turbulent flows and for homogeneous and isotropic turbulence, respectively. It is found that in the central region is dominated by contributions from the turbulent background rather than from the buoyancy force, and the Heisenberg–Yaglom relation holds in this region. From this, we obtain the first experimental results of the constant of the acceleration variance in the micro-scale Reynolds number range , which fills a gap in this constant in the lower end from the experimental side, and provides possible constraints for its high behaviour if a certain fitting function is attempted. In addition, acceleration correlation functions were obtained for different . It is found that the zero crossing time of acceleration correlation functions is at ( is the Kolmogorov time scale) over the range of spanned in our experiments, which is the same as the simulation results in isotropic turbulence, and the exponential decay time , which is larger than found experimentally for other types of turbulent flows with larger .
A tuffaceous claystone sample collected from a seamount flank of the Mariana Trench's ocean-ward slope by the Japanese submersible “Shinkai 6500” yielded very well-preserved earliest Cretaceous radiolarians. Initial spicule-bearing spherical radiolarians assignable to the families Centrocubidae and probably Entactiniidae have been identified in this radiolarian fauna. Based on the initial spicule and the connecting arches, we describe one new genus, Marianasphaera, belonging to the family Centrocubidae and another new genus called Shinkaiera, which is questionably assigned to the family Entactiniidae. Three new species, Marianasphaera ogawai, M. multispinosa, and Shinkaiera fragilis, are also described. These radiolarians provide important data, filling the gap between Triassic and Cenozoic initial spicule-bearing spherical radiolarians.
An optimal protocol for cryopreservation of boar semen was established. First, the boar semen was pre-diluted with ZORLESCO (ZO) solution and pre-equilibrated at room temperature for 1 h. After adding extender I, spermatozoa were equilibrated at 5°C for 1.5 h; then an equal volume of extender II was added and the spermatozoa equilibrated for 2 h. The resulting spermatozoa were loaded into 0.25 ml straws, equilibrated for 10 min at 3 cm above the surface of liquid nitrogen (LN), then promptly submerged into LN. When thawing, straws were incubated in a water bath at 37°C for 30 s. This procedure yielded the highest post-thaw motility of 0.58±0.03 and plasma integrity of 63.2±1.2%, together with a normal acrosome in 51.4±2.6% of spermatozoa. Abnormal spermatozoa after freezing represented only 14.0±3.0%.
First-principles calculations by the use of a plane-wave pseudopotential method are performed to investigate intrinsic point defect behavior in TiNi. The results show that TiNi is an antisite type intermetallic compound. The calculated interaction energies between the point defects demonstrate that Ti antisites are attractive to each other whereas Ni antisites are mutually repulsive. The attraction between Ti antisites indicates that excess Ti in TiNi may agglomerate so that a Ti-rich phase can easily precipitate. The repulsion between Ni antisites implies that the excess Ni is of certain solubility in TiNi. This result explains well the asymmetric feature of TiNi field on the binary phase diagram. In order to understand the correlation between the composition dependent elastic modulus and martensitic transformation (MT) temperature, the elastic moduli critical to MT, i.e., c′ and c44, are calculated as a function of the composition of the off-stoichiometric TiNi and a series of ternary TiNi-X alloys, by the use of exact muffin-tin orbital method in combination with coherent potential approximation. It turns out that, generally speaking, the early transition metal (TM) alloying elements in the periodic table increase c′ but decrease c44; the middle ones increase both c′ and c44, whereas the late ones decrease c′ but increase c44. An examination of the theoretical composition dependent elastic modulus and the experimental MT temperature shows that the MT temperature is more sensitive to the variation of c44 than to that of c′.
The effects of different concentrations of tumour necrosis factor-α (TNF-α) on rat adipocyte apoptosis were detected by optical microscopy, agarose gel electrophoresis and flow cytometry methods. The morphological changes of rat adipocyte apoptosis induced by TNF-α correlated linearly with the concentration of TNF-α, ranging from 5 to 20 ng/ml. High concentrations of TNF-α induced more obvious apoptosis. Significant morphological changes of rat adipocytes treated with 5 ng/ml TNF-α were noticed, but DNA ladders did not appear in the DNA electrophoresis analysis, i.e. morphological changes occurred earlier than the biochemical changes. TNF-α induced apoptosis in the rat adipocyte in a dose-dependent manner. The induced apoptotic effect of 5, 10, 15 and 20 ng/ml TNF-α was significantly different (P0.01), but the effect among 10, 15 and 20 ng/ml TNF-α treatments was not significantly different (P0.05). Thus the optimum concentration of TNF-α for inducing apoptosis was 10 ng/ml.
Secular variations in the carbon isotopic composition of organic and carbonate carbon characterize the Lower to Middle Cambrian transition that is exposed on the Yangtze Platform at Taijiang, Guizhou Province, southern China. δ13C values for organic matter range between −33.4 and −26.5‰. The carbon isotopic composition for carbonate carbon fluctuates between −2.7 and +3.1‰. A progressive decrease in the isotopic difference (Δδ) between these two isotope records reflects a decrease in the proportional contribution of bacterial biomass to the total sedimentary organic matter. In general, the observed changes are interpreted to reflect primary depositional values, notably variations in the burial rates of organic matter. These, in turn, are linked to biological changes across the Lower to Middle Cambrian transition. No distinct shift in the carbon isotopic composition marks the proposed Lower–Middle Cambrian boundary.