Alternate passage divergence of wide chord transonic fan blades

Due to manufacturing tolerance and deterioration during operation, fan blades in the same engine exhibit geometric variability. The absence of symmetry will inevitably exacerbate and contribute to the complexities of running geometry prediction as the blade variability is bound to be amplified by aerodynamic and centrifugal loading. In this study, the fan blade untwist (which is the blade deformation between its static condition and running condition) related phenomenon known as Alternate Passage Divergence (APD) is addressed. As the name suggests, APD manifests as alternating passage geometry (and hence alternating tip stagger pattern) when the fan stage is operating close to/at peak efficiency condition. APD can introduce adverse influence on fan performance, aeroacoustics behaviour, and high cycle fatigue characteristics of the blade. In this study, the APD behaviours of two transonic fan blade designs are compared. The main objective of the study is to identify the parameters contributing to the APD phenomenon. After the formation of alternating tip stagger pattern, APD's unsteady effect can cause the blades from one group (segmented by tip stagger angle) to switch to the other, creating a travelling wave pattern around the circumference. It was found from numerical assessment on a randomly mis-staggered assembly that real engines can potentially experience such travelling disturbance and suffer fatigue damage. The phenomenon is termed APD-induced Non-Synchronous Vibration (NSV) and is abbreviated as NSV in this study. An idealised case is used to capture the bulk behaviour from the more complex cases in real engines and to decipher the underlying mechanism of this travelling disturbance. The results indicate that the driving force originates from the interaction between passage shock displacement and the passage geometry. Based on the findings on APD & NSV, vibration attenuation methods are explored. Using machine learning techniques, a passive attenuation method is found to minimise the chance of NSV manifestation for a given set of fan blades. Alternatively, active attenuation method is implemented through blade redesign which modifies the passage geometry.Open Acces

Deep Learning-Based Long Term Mortality Prediction in the National Lung Screening Trial

In this study, the long-term mortality in the National Lung Screening Trial (NLST) was investigated using a deep learning-based method. Binary classification of the non-lung-cancer mortality (i.e. cardiovascular and respiratory mortality) was performed using neural network models centered around a 3D-ResNet. The models were trained on a participant age, gender, and smoking history matched cohort. Utilising both the 3D CT scan and clinical information, the models can achieve an AUC of 0.73 which outperforms humans at cardiovascular mortality prediction. The corresponding F1 and Matthews Correlation Coefficient are 0.60 and 0.38 respectively. By interpreting the trained models with 3D saliency maps, we examined the features on the CT scans that correspond to the mortality signal. By extracting information from 3D CT volumes, we can highlight regions in the thorax region that contribute to mortality that might be overlooked by the clinicians. Therefore, this can help focus preventative interventions appropriately, particularly for under-recognised pathologies and thereby reducing patient morbidity

A hybrid CNN-RNN approach for survival analysis in a Lung Cancer Screening study

In this study, we present a hybrid CNN-RNN approach to investigate long-term survival of subjects in a lung cancer screening study. Subjects who died of cardiovascular and respiratory causes were identified whereby the CNN model was used to capture imaging features in the CT scans and the RNN model was used to investigate time series and thus global information. To account for heterogeneity in patients' follow-up times, two different variants of LSTM models were evaluated, each incorporating different strategies to address irregularities in follow-up time. The models were trained on subjects who underwent cardiovascular and respiratory deaths and a control cohort matched to participant age, gender, and smoking history. The combined model can achieve an AUC of 0.76 which outperforms humans at cardiovascular mortality prediction. The corresponding F1 and Matthews Correlation Coefficient are 0.63 and 0.42 respectively. The generalisability of the model is further validated on an 'external' cohort. The same models were applied to survival analysis with the Cox Proportional Hazard model. It was demonstrated that incorporating the follow-up history can lead to improvement in survival prediction. The Cox neural network can achieve an IPCW C-index of 0.75 on the internal dataset and 0.69 on an external dataset. Delineating subjects at increased risk of cardiorespiratory mortality can alert clinicians to request further more detailed functional or imaging studies to improve the assessment of cardiorespiratory disease burden. Such strategies may uncover unsuspected and under-recognised pathologies thereby potentially reducing patient morbidity

Improving Surface Soil Moisture Estimation Through Assimilating Satellite Land Surface Temperature With a Linear SM-LST Relationship

Soil moisture (SM) plays a vital role in linking the global terrestrial water, energy, and carbon cycles. Land data assimilation (DA) is typically applied for acquiring more accurate SM estimates by incorporating remote sensing (RS) retrievals to constraint model parameters and system states. In addition to RS SM retrievals that are frequently used in land DA, the land surface temperature (LST), which can be directly and independently retrieved from thermal infrared measurements, is closely linked with SM, and can also be used in the land DA to improve SM estimation. However, it is hampered by the lack of a general observation operator that links LST retrievals with SM in the land surface model (LSM). Therefore, a novel LST DA scheme is developed in this article, in which RS LST is linked to SM by a linear relationship between the simulated ensembles of SM and LST generated by the Ensemble Kalman filter. Subsequently, MODIS LST is assimilated into the LSM to estimate SM and calibrate the soil parameters (soil porosity, soil texture) with the dual-cycle assimilation algorithm. The DA SM results are validated using an in situ SM network deployed in the central Tibetan Plateau. The results demonstrate that our DA scheme improved the SM accuracy—leading to a decrease in the root-mean-square error from 0.11 m3m−3 to 0.026 m3m−3. This article provides a novel scheme of LST assimilation, which is beneficial for the assimilation of high-resolution RS data

Neural repair and rehabilitation: Prolonged neural stem cell maturation restores motor function in spinal cord-lesioned rats

In Brief comment on original article Lu, P. et al. Prolonged human neural stem cell maturation supports recovery in injured rodent CNS. J. Clin. Invest. https://dx.doi.org/10.1172/JCI92955 (2017

Decoction regulating phytochemicals’ micromorphology changes and anti-inflammation activity enhancements originated from herb medicine supermolecules

Abstract Background Mahuang Fuzi decoction (MGF) is composed of three herb medicines that has been clinically used to treat inflammatory diseases for a long history. At present, more and more active phytochemicals’ aggregations have been found during the thermodynamic process of herb medicine decoction, and revealing the clinical efficacy of herb medicine through supramolecular strategies is the focus of current research. However, it is not clear whether decoction induced supermolecules’ morphological changes to modify activity. Methods Dynamic light scattering (DLS) and field emission scanning electron microscopy (FESEM) were used to analyze the micromorphology of MGF, MGF SA (MGF supermolecules), and MIX (physical mixture of MGF single decoction). The interaction and thermodynamic parameters of single herbs in a decoction were investigated by Isothermal titration calorimetry (ITC). The phytochemicals were systematically analyzed by ultra high performance liquid chromatography-Q Exactive hybrid quadrupole-orbitrap high-resolution accurate mass spectrometry (UHPLC-Q-Orbitrap HRMS). Under the safe dose on RAW264.7 cells, NO, IL-6 and TNF-α were determined by Enzyme-Linked ImmunoSorbent Assay (ELISA) method. NF-κB p65 translocation from the cytoplasm into the nucleus was examined using the immunofluorescence assay and the western blot, respectively. Furthermore, Metabolomics was used to discover potential biomarkers and the associated metabolic pathways of MGF SA treatment. Results There were nanoscale aggregations in MGF, and the micromorphology of the extracted MGF SA consisted of uniform particles; while the MIX micromorphology had no uniformity. ITC showed that the interaction MH-GC and FZ-GC were a spontaneous exothermic reaction, indicating that their phytochemicals had the property of self-assembly. Though the micromorphology between MGF, MGF SA, and MIX was obviously different, UHPLC-Q-Orbitrap HRMS results displayed that the main phytochemicals of MGF and MIX had nearly the same components. Interestingly, MGF and MGF SA could significantly inhibit the production of NO, and had better inhibition effect on the expression of nuclear protein NF-κB p65 than MIX, among which MGF SA had the best effect. Further investigation indicated that the perturbance of metabolic profiling in RAW264.7 inflammatory cells was obviously reversed by MGF SA. Conclusions The decoction enriched the key active phytochemicals and regulated the formation of homogeneous nanoparticles in MGF SA. The supermolecules in MGF SA significantly enhanced its anti-inflammatory activity, primarily affecting the NF-κB signaling pathway and the biosynthesis and metabolism of arginine in RAW264.7 inflammatory cells. Current study displayed that co-decocting herbal medicine were beneficial to the treatment of diseases than the mixture of the single herbs’ extraction. Graphical Abstrac

Long-Distance Axonal Growth from Human Induced Pluripotent Stem Cells after Spinal Cord Injury

Human induced pluripotent stem cells (iPSCs) from a healthy 86-year-old male were differentiated into neural stem cells and grafted into adult immunodeficient rats after spinal cord injury. Three months after C5 lateral hemisections, iPSCs survived and differentiated into neurons and glia and extended tens of thousands of axons from the lesion site over virtually the entire length of the rat CNS. These iPSC-derived axons extended through adult white matter of the injured spinal cord, frequently penetrating gray matter and forming synapses with rat neurons. In turn, host supraspinal motor axons penetrated human iPSC grafts and formed synapses. These findings indicate that intrinsic neuronal mechanisms readily overcome the inhibitory milieu of the adult injured spinal cord to extend many axons over very long distances; these capabilities persist even in neurons reprogrammed from very aged human cells.Video abstrac

Nanoparticles Self-Assembled from Berberine and Chrysin for Generating Antimicrobial Films

Methicillin-resistant Staphylococcus aureus (MRSA) and Candida albicans (CA) are common pathogenic organisms in humans and pose a severe threat to public health. Coinfection of MRSA and CA often forms durable biofilms on abiotic surfaces or in the host, which is the main strategy for these pathogens to resist antibiotics and escape from host immune surveillance. However, the limited options of available antibiotics and the emergence of drug-resistant strains further increase the difficulty in treating microbial infections. Inspired by the clinical application of traditional herbal medicines, we prepare natural small molecule carrier-free binary nanoparticles (NPs), which are self-assembled from berberine and chrysin through a one-pot method. Interestingly, the pharmacologic mechanisms of the NPs against MRSA and CA are different. We show here that NPs plays an anti-MRSA effect by inducing cell death, while NPs inhibit CA by causing prolonged M phase progression, abnormal cytokinesis, diminished hyphal growth, and disturbed cell wall. Furthermore, NPs exhibit inhibition and eradication of mono- and dual-species biofilms of MRSA and CA. Given the excellent antimicrobial activities of NPs, the NPs show no obvious hemolytic and cytotoxicity, suggesting that they have desired clinical application value in the treatment coinfection of MRSA and CA