Search

ObjectivePre-eclampsia (PE) is one of the malignant metabolic diseases that complicate pregnancy. Gut dysbiosis has been identified for causing metabolic diseases, but the role of gut microbiome in the pathogenesis of PE remains unknown.DesignWe performed a case–control study to compare the faecal microbiome of PE and normotensive pregnant women by 16S ribosomal RNA (rRNA) sequencing. To address the causative relationship between gut dysbiosis and PE, we used faecal microbiota transplantation (FMT) in an antibiotic-treated mouse model. Finally, we determined the microbiome translocation and immune responses in human and mouse placental samples by 16S rRNA sequencing, quantitative PCR and in situ hybridisation.ResultsPatients with PE showed reduced bacterial diversity with obvious dysbiosis. Opportunistic pathogens, particularly Fusobacteriumand Veillonella, were enriched, whereas beneficial bacteria, including Faecalibacteriumand Akkermansia, were markedly depleted in the PE group. The abundances of these discriminative bacteria were correlated with blood pressure (BP), proteinuria, aminotransferase and creatinine levels. On successful colonisation, the gut microbiome from patients with PE triggered a dramatic, increased pregestational BP of recipient mice, which further increased after gestation. In addition, the PE-transplanted group showed increased proteinuria, embryonic resorption and lower fetal and placental weights. Their T regulatory/helper-17 balance in the small intestine and spleen was disturbed with more severe intestinal leakage. In the placenta of both patients with PE and PE-FMT mice, the total bacteria, Fusobacterium, and inflammatory cytokine levels were significantly increased.ConclusionsThis study suggests that the gut microbiome of patients with PE is dysbiotic and contributes to disease pathogenesis.

Process simulations of conduction mode laser welding are performed using the meshless Lagrangian smoothed particle hydrodynamics (SPH) method. The solid phase is modeled based on the governing equations in thermoelasticity. For the liquid phase, surface tension effects are taken into account to simulate the melt flow in the weld pool, including the Marangoni force caused by a temperature-dependent surface tension gradient. A non-isothermal solid–liquid phase transition with the release or absorption of additional energy known as the latent heat of fusion is considered. The major heat transfer through conduction is modeled, whereas heat convection and radiation are neglected. The energy input from the laser beam is modeled as a Gaussian heat source acting on the initial material surface. The developed model is implemented in Pasimodo. Numerical results obtained with the model are presented for laser spot welding and seam welding of aluminum and iron. The change of process parameters like welding speed and laser power, and their effects on weld dimensions are investigated. Furthermore, simulations may be useful to obtain the threshold for deep penetration welding and to assess the overall welding quality. A scalability and performance analysis of the implemented SPH algorithm in Pasimodo is run in a shared memory environment. The analysis reveals the potential of large welding simulations on multi-core machines.

The influence of Fe in the buffer layer on the laser liftoff (LLO) of GaN high electron mobility transistors is presented herein. LLO is performed on Fe‐doped GaN films using a KrF excimer LLO system. The morphology, crystal characteristics, and 2D electron gas (2DEG) characteristics of the GaN films after LLO are characterized using a 3D optical microscope, X‐ray diffraction, and Hall methods. The present work is different from previous methods because of the large‐area buckling instead of cracks on the Fe‐doped GaN films. The results show that the crystal quality and 2DEG characteristics of the buckled parts are significantly affected. Furthermore, a modified simulation model of the temperature and thermal‐induced stress fields in the films is used to explain the buckling of the films, whose results are consistent with the characterization results. The additional absorption centers induced by the Fe impurity energy levels increase the gradient of temperature field, thereby increasing the compressive stresses in the films at the edges of the laser spots. Moreover, a higher temperature is observed at the interface between the film and the bonding glue, which results in the debonding. Therefore, Fe‐doped GaN films are more prone to buckling than unintentionally doped GaN films. Herein, it is reported that a large‐area buckling occurs when the Fe‐doped GaN high electron mobility transistor (HEMT) film is separated from the sapphire substrate by a laser liftoff process. A simulation model of the temperature and thermal‐induced stress fields in the films combined with the model of film buckling is used to explain the buckling mechanism.