In this research, 12CrNi2 low alloy steel was successfully prepared by laser melting deposition (LMD). The mechanisms driving high cycle fatigue fracture of the as-built LMD 12CrNi2 low alloy steel ...were investigated and a concurrent process-microstructure-property relationship was established through microstructural analysis. The results showed that the crystal structures of the as-built LMD 12CrNi2 steel mainly consisted of the ferrite and a small amount of Cr23C6 carbides. No preferred texture was observed as a result of the complicated heat flux direction during fabrication. Based on the examination of the fracture surface, fatigue cracks of the as-built LMD 12CrNi2 steel initiated from subsurface defects for all the cases. Crack propagation zones showed a mixed mode of transgranular and intergranular fracture in a brittle manner, whereas the final fracture zones displayed dimples typical of ductile fracture. The kernel average misorientation (KAM) map indicated that the strain localization predominantly occurred at the grain boundaries and slightly appeared at the interior of the ferrite grains. Schmid factor distribution results implied that fatigue cracks originated from grains with {123} slip system due to the prior activation of {123} slip system.
Introduction
Depression (MDD) is a serious mental illness, which greatly affects the quality of life of patients. Nowadays, the clinical diagnosis of MDD lacks sufficient objective basis, and the ...effect of drug treatment is unsatisfactory. Therefore, biomarkers are very important for the risk prediction, classification, diagnosis and prognosis of MDD.
Objectives
Research progress of metabonomics of blood endogenous small molecules in depression
Methods
Metabonomics is a newly developed discipline after genomics and proteomics, and is an important part of system biology. Metabonomics provides a new approach to explore the etiology, mechanism, prognosis and screening potential biomarkers of MDD. Blood contains almost all the small molecule metabolites in the body. The changes of metabolites in blood can represent the changes of metabolites in other body fluids. Moreover, this sample is easy to obtain and has less trauma, so it is the most common biological sample in clinical detection.
Results
At present, there are many studies on the metabonomics of endogenous small molecules in MDD blood, which provides the possibility for further screening of MDD related biomarkers.
Conclusions
In this paper, the research progress of related biomarkers in MDD blood is reviewed.
Disclosure
No significant relationships.
Abstract Introduction Pathogenesis of early-onset preeclampsia (PE) is generally recognized by impaired trophoblast invasion of the myometrial arteries, which results in placental insufficiency. ...Recently, we reported that CDX1 is hypermethylated in the human preeclampsia placenta. However, whether CDX1 participates in trophoblast invasion has not been clearly elucidated. Methods We investigated the function of CDX1 in the extravillous trophoblast cell line HTR-8/SVneo using stable transfection of CDX1. Using a CDX1 stable transfected cell line, we determined the cell invasion using a QCM ECMatrix 24-well kit. The cell viability was detected using an MTT (3-4, 5-dimethylthiazol-2-yl-2, 5-diphenyltetrazolium bromide) assay. Quantitative RT-PCR and western blotting analyses were performed to examine the changes in the expression of downstream target genes and proteins. To disrupt PI3K/AKT signaling, we used the PI3K inhibitor perifosine. Results Cell invasion assays demonstrated that CDX1 restricts trophoblast cell invasiveness. In contrast, quantification of cumulative cell numbers revealed that CDX1 did not affect cell proliferation. Western blotting analysis and quantitative real time PCR demonstrated that MMP-9 expression was reduced, whereas TIMP-1 expression was increased in CDX1-overexpressed cells. However, overexpression of CDX1 did not affect PI3K/AKT signaling in HTR-8/SVneo trophoblast cells. In contrast, CDX1 was regulated by the PI3K/AKT signaling pathway. Conclusions Altogether, we found that in trophoblast cells, CDX1 reduced invasion independently of the PI3K/AKT signaling pathway. Furthermore, CDX1 functions in concert with PI3K/AKT signaling to regulate trophoblast invasion. We concluded that CDX1 restricts the invasion of HTR-8/SVneo trophoblast cells by inhibiting MMP-9 expression independently of the PI3K/AKT pathway.
This study aimed to develop a diagnostic model for predicting early surgical site infection (SSI) based on postoperative inflammatory markers after spinal fusion surgery.
In this retrospective study, ...we analysed the trends of inflammatory markers between SSI and non-SSI groups. The data were randomly divided into training cohort and validation cohort (ratio 7:3). The variables for SSI were analysed using stepwise logistic regression to develop the prediction model. To evaluate the model, we analysed its sensitivity, specificity, positive predictive value, negative predictive value, as well as the area under the curve in the validation cohort. Calibration plots and decision curve analysis were employed to assess the calibration and clinical usefulness of the model.
We observed significant changes in inflammatory markers on the seventh day after surgery. The prediction model included four variables on the seventh day after surgery: body temperature, C-reactive protein, erythrocyte sedimentation rate and neutrophil counts. After binary processing of these data, the simplified model achieved an area under the curve of 0.86 (95% confidence interval (CI): 0.81–0.92) in the training cohort and 0.9 (95% CI: 0.82–0.98) in the validation cohort. Calibration plots and decision curve analysis demonstrated that the proposed model was effective for the diagnosis of SSI.
We developed and validated a prediction model for diagnosing early infection after spinal fusion.
Seismic ground motions at multiple sites are nonstationary and non‐Gaussian with potentially time‐ and frequency‐dependent coherence, although the nonstationarity or non‐Gaussian or time‐dependent ...coherence aspects are often neglected because of lack of algorithm or method to take all these aspects into account to simulate synthetic ground motion records at multiple sites. In the present study, an iterative power and amplitude correction algorithm is proposed to simulate the nonstationary and non‐Gaussian vector process and takes into account time‐ and frequency‐dependent coherence. The algorithm usually converges within 10 iterations. It can be viewed as the extension of the well‐known iterative amplitude adjust Fourier transform algorithm for generating a vector of surrogates. The proposed algorithm uses the S‐transform and discrete orthonormal S‐transform rather than the ordinary Fourier transform. The adequacy of the proposed algorithm is validated numerically by using simulated ground motions.
Purpose
To determine R2 and R2′$$ {R}_2^{\prime } $$ transverse relaxation rates in healthy lung parenchyma at 0.55 T. This is important in that it informs the design and optimization of new imaging ...methods for 0.55T lung MRI.
Methods
Experiments were performed in 3 healthy adult volunteers on a prototype whole‐body 0.55T MRI, using a custom free‐breathing electrocardiogram‐triggered, single‐slice echo‐shifted multi‐echo spin echo (ES‐MCSE) pulse sequence with respiratory navigation. Transverse relaxation rates R2 and R2′$$ {R}_2^{\prime } $$ and off‐resonance ∆f were jointly estimated using nonlinear least‐squares estimation. These measurements were compared against R2 estimates from T2‐prepared balanced SSFP (T2‐Prep bSSFP) and R2*$$ {R}_2^{\ast } $$ estimates from multi‐echo gradient echo, which are used widely but prone to error due to different subvoxel weighting.
Results
The mean R2 and R2′$$ {R}_2^{\prime } $$ values of lung parenchyma obtained from ES‐MCSE were 17.3 ± 0.7 Hz and 127.5 ± 16.4 Hz (T2 = 61.6 ± 1.7 ms; T2′$$ {\mathrm{T}}_2^{\prime } $$ = 9.5 ms ± 1.6 ms), respectively. The off‐resonance estimates ranged from −60 to 30 Hz. The R2 from T2‐Prep bSSFP was 15.7 ± 1.7 Hz (T2 = 68.6 ± 8.6 ms) and R2*$$ {R}_2^{\ast } $$ from multi‐echo gradient echo was 131.2 ± 30.4 Hz (T2*$$ {\mathrm{T}}_2^{\ast } $$ = 8.0 ± 2.5 ms). Paired t‐test indicated that there is a significant difference between the proposed and reference methods (p < 0.05). The mean R2 estimate from T2‐Prep bSSFP was slightly smaller than that from ES‐MCSE, whereas the mean R2′$$ {R}_2^{\prime } $$ and R2*$$ {R}_2^{\ast } $$ estimates from ES‐MCSE and multi‐echo gradient echo were similar to each other across all subjects.
Conclusions
Joint estimation of transverse relaxation rates and off‐resonance is feasible at 0.55 T with a free‐breathing electrocardiogram‐gated and navigator‐gated ES‐MCSE sequence. At 0.55 T, the mean R2 of 17.3 Hz is similar to the reported mean R2 of 16.7 Hz at 1.5 T, but the mean R2′$$ {R}_2^{\prime } $$ of 127.5 Hz is about 5–10 times smaller than that reported at 1.5 T.
Neural electrodes hold tremendous potential for improving understanding of brain function and restoring lost neurological functions. Multi-walled carbon nanotube (MWCNT) and dexamethasone (Dex)-doped ...poly(3,4-ethylenedioxythiophene) (PEDOT) coatings have shown promise to improve chronic neural electrode performance. Here, we employ electrochemical techniques to characterize the coating in vivo. Coated and uncoated electrode arrays were implanted into rat visual cortex and subjected to daily cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) for 11 days. Coated electrodes experienced a significant decrease in 1 kHz impedance within the first two days of implantation followed by an increase between days 4 and 7. Equivalent circuit analysis showed that the impedance increase is the result of surface capacitance reduction, likely due to protein and cellular processes encapsulating the porous coating. Coating's charge storage capacity remained consistently higher than uncoated electrodes, demonstrating its in vivo electrochemical stability. To decouple the PEDOT/MWCNT material property changes from the tissue response, in vitro characterization was conducted by soaking the coated electrodes in PBS for 11 days. Some coated electrodes exhibited steady impedance while others exhibiting large increases associated with large decreases in charge storage capacity suggesting delamination in PBS. This was not observed in vivo, as scanning electron microscopy of explants verified the integrity of the coating with no sign of delamination or cracking. Despite the impedance increase, coated electrodes successfully recorded neural activity throughout the implantation period.
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