Airfoil-gust interactions in transonic flow

Leading edge noise is a significant broadband noise source in aircraft engines, and is the primary broadband noise mechanism in outlet guide vane noise in turbofans, and broadband rotor wake interaction noise in contra-rotating open rotor engines. Previous authors have studied the effects of various aspects relating to this noise source, including airfoil geometry effects, cascade effects, and Mach number effects. However, previous literature has not addressed the effects on the noise due to locally supersonic regions that might be present inthe mean flow around the rotor blades. The current work uses computational aeroacoustic methods to investigate the effects of locally supersonic regions on the noise due to airfoil-gust interactions. An established computational aeroacoustics code has been extended to give stable predictions in supersonic regions with a localized artificial diffusivity method.Initial results of a NACA 0012 airfoil in M = 0.8 flow interacting with oncoming vortical waves are shown, alongside results for a NACA 0006 airfoil in M = 0.5 flow at a 6 ? angle of attack. The changes to the noise and the underlying mechanisms are discussed for both cases, including additional noise sources caused by the supersonic region

Flexible Robotic Scanning Device for Intraoperative Endomicroscopy in MIS

Optical biopsy methods such as probe-based confocal endomicroscopy can provide intraoperative real-time assessment of tumour margins, including during minimally invasive surgery with flexible endoscopes or robotic platforms. Mosaics can be produced by translating the probe across the target, but it remains difficult to scan over a large field-of-view with a flexible endomicroscope. In this paper, we have developed a novel flexible scanning device for intraoperative endomicroscopy in MIS. A Schott leached imaging bundle was integrated into the device and enables the approach, via a flexible path, to deep and narrow spaces in the human body that otherwise would not accessible. The proposed device uses a gear-based flexible concentric tube scanning mechanism to facilitate large field-of-view mosaicing. Experimental results show that the device is able to scan different surface trajectories (e.g. a spiral pattern over a hemi-spherical surface). Results from lens tissue paper and porcine liver tissue are demonstrated, illustrating a viable scanning approach for endomicroscopy in MIS

The role of circadian clock in astrocytes: From cellular functions to ischemic stroke therapeutic targets

Accumulating evidence suggests that astrocytes, the abundant cell type in the central nervous system (CNS), play a critical role in maintaining the immune response after cerebral infarction, regulating the blood-brain barrier (BBB), providing nutrients to the neurons, and reuptake of glutamate. The circadian clock is an endogenous timing system that controls and optimizes biological processes. The central circadian clock and the peripheral clock are consistent, controlled by various circadian components, and participate in the pathophysiological process of astrocytes. Existing evidence shows that circadian rhythm controls the regulation of inflammatory responses by astrocytes in ischemic stroke (IS), regulates the repair of the BBB, and plays an essential role in a series of pathological processes such as neurotoxicity and neuroprotection. In this review, we highlight the importance of astrocytes in IS and discuss the potential role of the circadian clock in influencing astrocyte pathophysiology. A comprehensive understanding of the ability of the circadian clock to regulate astrocytes after stroke will improve our ability to predict the targets and biological functions of the circadian clock and gain insight into the basis of its intervention mechanism

The complete reference genome for grapevine (Vitis vinifera L.) genetics and breeding

Grapevine is one of the most economically important crops worldwide. However, the previous versions of the grapevine reference genome consisted of thousands of fragments with missing centromeres and telomeres, which limited the accessibility of the repetitive sequences, the centromeric and telomeric regions, and the inheritance of important agronomic traits in these regions. Here, we assembled a telomere-to-telomere (T2T) gap-free reference genome for the pinot noir cultivar (PN40024) using the PacBio HiFi long reads. The T2T reference genome (PN_T2T) was 69 Mb longer with 9026 more genes identified than the 12X.v2 version (Canaguier et al., 2017). We annotated 67% repetitive sequences, 19 centromeres and 36 telomeres, and incorporated gene annotations of previous versions into the PN_T2T. We detected a total of 377 gene clusters, which showed associations with complex traits, such as aroma and disease resistance. Even though the PN40024 sample had been selfed for nine generations, we still found nine genomic hotspots of heterozygous sites associated with biological processes, such as the oxidation-reduction process and protein phosphorylation. The fully annotated complete reference genome, therefore, provides important resources for grapevine genetics and breeding.This work was supported by the National Natural Science Fund for Excellent Young Scientists Fund Program (Overseas) to Yongfeng Zhou, the National Key Research and Development Program of China(grant2019YFA0906200), the Agricultural Science and Technology Innovation Program (CAAS-ZDRW202101), the Shenzhen Science and Technology Program (grant KQTD2016113010482651), the BMBF funded de.NBI Cloud within the German Network for Bioinformatics Infrastructure (de.NBI). We thank Bianca Frommer, Marie Lahaye, David Navarro-Payá, Marcela K. Tello-Ruiz and Kapeel Chougule for their help in analyzing the RNA-Seq data and in running the gene annotation pipeline. This study is also based upon work from COST Action CA17111 INTEGRAPE and form COST Innovators Grant IG17111 GRAPEDIA, supported by COST (European Cooperation in Science and Technology).ViticultureT2Tgap-fregene clustercentromeretelomerePublishe

A balloon endomicroscopy scanning device for diagnosing barrett's oesophagus

Confocal endomicroscopy can be used for identification of early mucosal dysplasia in various gastrointestinal conditions, and has particular potential in the monitoring of Barrett's oesophagus and the early stages of oesophageal cancer. However, it can be difficult to systematically scan a significant area of the oesophagus because of the small field-of-view and limited flexibility of the probe. Tissue deformation and inconsistent probe-tissue contact also make it difficult to form large mosaics. A mechanical scanning device is therefore desirable for controlled, large area surface scanning and mosaicing of the oesophagus. This paper proposes a robotic catheter encapsulated in an inflatable balloon, providing stable scanning over the oesophageal surface. It has an outer diameter of 3 mm, making it suitable for deployment through an endoscope working channel, and uses a custom endomicroscopy probe based on a leached flexible fibre bundle and an external confocal laser scanning system. Detailed mechanical performance and image quality evaluations were performed to assess the clinical potential of the device. In ex vivo studies using swine oesophagus, long helical scans were obtained, demonstrating that the device is able to scan the lumen stably and maintain good probe-tissue contact. The experimental results demonstrate the potential of the robotic catheter for systematic high-resolution imaging of the oesophageal mucosa, potentially reducing or even eliminating the need for physical biopsy

Supplementary material from A generalized sound extrapolation method for turbulent flows

Sound extrapolation methods are often used to compute acoustic far-field directivities using near-field flow data in aeroacoustics applications. The results may be erroneous if the volume integrals are neglected (to save computational cost), while non-acoustic fluctuations are collected on the integration surfaces. In this work, we develop a new sound extrapolation method based on an acoustic analogy using Taylor's hypothesis (Taylor 1938 <i>Proc. R. Soc. Lon. A</i> <b>164</b>, 476–490. (doi:10.1098/rspa.1938.0032)). Typically, a convection operator is used to filter out the acoustically inefficient components in the turbulent flows, and an acoustics dominant indirect variable _c<i>p</i>' is solved. The sound pressure <i>p</i>^′ at the far field is computed from _c<i>p</i>' based on the asymptotic properties of the Green's function. Validations results for benchmark problems with well-defined sources match well with the exact solutions. For aeroacoustics applications: the sound predictions by the aerofoil–gust interaction are close to those by an earlier method specially developed to remove the effect of vortical fluctuations (Zhong & Zhang 2017 <i>J. Fluid Mech.</i> <b>820</b>, 424–450. (doi:10.1017/jfm.2017.219)); for the case of vortex shedding noise from a cylinder, the off-body predictions by the proposed method match well with the on-body Ffowcs-Williams and Hawkings result; different integration surfaces yield close predictions (of both spectra and far-field directivities) for a co-flowing jet case using an established direct numerical simulation database. The results suggest that the method may be a potential candidate for sound projection in aeroacoustics applications