43 research outputs found

    LES of flow through and around a finite patch of thin plates

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    Large eddy simulations (LESs) are performed for turbulent flow through and around a porous patch of thin vertical plates at a plate Reynolds number of Rep=5,800. The plates are arranged in a staggered pattern, presenting an elliptical planform and mimicking streamwise‐oriented blades of emergent vegetation. The immersed boundary method is employed to explicitly resolve the interaction between flow and plates. Three flow cases, each with a different number of plates within the same planform area, that is, different patch density, are studied. The Reynolds number based on freestream velocity and plate length is the same in all cases. Inspection of the distribution of velocity and vorticity in the horizontal plane reveals that downstream plates are significantly impacted by the wakes from upstream plates. It is therefore proposed that the plates can be divided into two groups based on the local flow characteristics, which are a function of position within the patch: a free group and a wake group. This classification is subsequently used in the quantitative analysis of boundary layer development and drag force at plate scale. The thickness and character of the simulated boundary layers on the plates differ significantly from predictions based on analytical or empirical relationships, which is due to wake effects and the finite length of the plates. The simulations demonstrate the so‐called sheltering effect; that is, the drag forces acting on downstream plates (in the wake group) are significantly lower than those acting on upstream plates, a result of the lower approach flow speed. Although the front‐area‐to‐lateral‐area ratio of the plates is low (1/40), pressure drag is observed to be larger than friction drag for each plate. The ratio of pressure drag to the total drag at patch scale shows only very little dependence on the plate density of the patch

    Surface-enhanced Raman Spectroscopy Facilitates the Detection of Microplastics < 1 Îźm in the Environment

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    Micro- and nanoplastics are considered one of the top pollutants that threaten the environment, aquatic life and mammalian (including human) health. Unfortunately, the development of uncomplicated but reliable analytical methods that are sensitive to individual microplastic particles, with sizes smaller than 1 Îźm, remains incomplete. Here, we demonstrate the detection and identification of (single) micro- and nanoplastics, by using surface-enhanced Raman spectroscopy (SERS), with Klarite substrates. Klarite is an exceptional SERS substrate; it is shaped as a dense grid of inverted pyramidal cavities, made of gold. Numerical simulations demonstrate that these cavities (or pits) strongly focus incident light into intense hotspots. We show that Klarite has the potential to facilitate the detection and identification of synthesized and atmospheric/aquatic microplastic (single) particles, with sizes down to 360 nm. We find enhancement factors of up to two orders of magnitude for polystyrene analytes. In addition, we detect and identify microplastics with sizes down to 450 nm on Klarite, with samples extracted from ambient, airborne particles. Moreover, we demonstrate Raman mapping as a fast detection technique for sub-micron microplastic particles. The results show that SERS with Klarite is a facile technique that has the potential to detect and systematically measure nanoplastics in the environment. This research is an important step towards detecting nanoscale plastic particles that may cause toxic effects to mammalian and aquatic life when present in high concentrations

    Impact of the CYP2C19*17 Allele on Outcomes in Patients Receiving Genotype-Guided Antiplatelet Therapy After Percutaneous Coronary Intervention.

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    Genotyping for CYP2C19 no function alleles to guide antiplatelet therapy after percutaneous coronary intervention (PCI) improves clinical outcomes. Although results for the increased function CYP2C19*17 allele are also reported, its clinical relevance in this setting remains unclear. A collaboration across nine sites examined antiplatelet therapy prescribing and clinical outcomes in 3,342 patients after implementation of CYP2C19-guided antiplatelet therapy. Risk of major atherothrombotic and bleeding events over 12 months after PCI were compared across cytochrome P450 2C19 isozyme (CYP2C19) metabolizer phenotype and antiplatelet therapy groups by proportional hazards regression. Clopidogrel was prescribed to a similar proportion of CYP2C19 normal (84.5%), rapid (82.9%), and ultrarapid metabolizers (80.6%) (P = 0.360). Clopidogrel-treated normal metabolizers (20.4 events/100 patient-years; adjusted hazard ratio (HR) 1.00, 95% confidence interval (CI), 0.75-1.33, P = 0.993) and clopidogrel-treated rapid or ultrarapid metabolizers (19.1 events/100 patient-years; adjusted HR 0.95, 95% CI, 0.69-1.30, P = 0.734) exhibited no difference in major atherothrombotic events compared with patients treated with prasugrel or ticagrelor (17.6 events/100 patient-years). In contrast, clopidogrel-treated intermediate and poor metabolizers exhibited significantly higher atherothrombotic event risk compared with prasugrel/ticagrelor-treated patients (adjusted HR 1.56, 95% CI, 1.12-2.16, P = 0.008). When comparing clopidogrel-treated rapid or ultrarapid metabolizers to normal metabolizers, no difference in atherothrombotic (adjusted HR 0.97, 95% CI, 0.73-1.29, P = 0.808) or bleeding events (adjusted HR 1.34, 95% CI, 0.83-2.17, P = 0.224) were observed. In a real-world setting of genotype-guided antiplatelet therapy, the CYP2C19*17 allele did not significantly impact post-PCI prescribing decisions or clinical outcomes. These results suggest the CYP2C19 *1/*17 and *17/*17 genotypes have limited clinical utility to guide antiplatelet therapy after PCI

    Pharmacogenomics of osteonecrosis of the jaw

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    Osteonecrosis of the jaw (ONJ) is a rare but serious drug induced adverse event, mainly associated with the use of antiresorptive medications, such as intravenous (IV) bisphosphonates (BPs) in cancer patients. In this review, we evaluated all the pharmacogenomic association studies for ONJ published up to December 2018. To date, two SNPs (CYP2C8 rs1934951 and RBMS3 rs17024608) were identified to be associated with ONJ by two genome-wide association studies (GWAS). However, all six subsequent candidate gene studies failed to replicate these results. In addition, six discovery candidate gene studies tried to identify the genetic markers in several genes associated with bone remodeling, bone mineral density, or osteoporosis. After evaluating the results of these 6 studies, none of the SNPs was significantly associated with ONJ. Recently, two whole-exome sequencing (WES) analysis (including one from our group) were performed to identify variants associated with ONJ. So far, only our study successfully replicated discovery result indicating SIRT1 SNP rs7896005 to be associated with ONJ. However, this SNP also did not reach genome-wide significance. The major limitations of these studies include lack of replication phases and limited sample sizes. Even though some studies had larger sample sizes, they recruited healthy individuals as controls, not subjects treated with BPs. We conclude that a GWAS with a larger sample size followed by replication phase will be needed to fully investigate the pharmacogenomic markers of ONJ

    Generation and characterization of expressed sequence tags (ESTs) from coralloid root cDNA library of Cycas debaoensis

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    A normalized full-length cDNA library was constructed from the coralloid roots of Cycas debaoensis by the DSN (duplex-specific nuclease) normalization method combined with the SMART (Switching Mechanism At 5′ end of the RNA Transcript) technique. The titer of the original cDNA library was about 1.5 × 106 cfu·mL−1 and the average insertion size was about 1 kb with a high recombination rate (97%). The 5011 high-quality expressed sequence tags (ESTs) were obtained from 5393 randomly picked cDNA clones. Clustering and assembly of ESTs resulted in 2984 unique sequences, consisting of 618 contigs and 2366 singlets. EST sequence annotation revealed that 2333 and 1901 unigenes were functionally annotated in the NCBI non-redundant database and Swiss-Prot protein database, respectively. Functional analysis demonstrated that 1495 (50.1%) unigenes were associated with 4082 Gene Ontology (GO) terms. A total of 847 unigenes were grouped into 22 Cluster of Orthologous Groups (COG) functional categories. Based on the EST dataset, 22 ESTs that encoded putative receptor-like protein kinase (RLK) genes were screened. Furthermore, a total of 94 simple sequence repeats (SSRs) were discovered, of which 20 loci were successfully amplified in C. debaoensis. This study is the first EST analysis for the coralloid roots of C. debaoensis and provides a valuable genomic resource for novel gene discovery, gene expression and comparative genomics, conservation and management studies as well as applications in C. debaoensis and related cycad species. Keywords: Cycas debaoensis, Coralloid root, cDNA library, Expressed sequence tags, Symbiosis and defense, SSR

    Robust energy-efficient precoding optimization for dual-polarized multiuser MIMO downlink

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    In this paper, we propose the robust fairness-based energy efficiency (EE) optimization of the dual-polarized multiuser multiple-input multiple-output (MIMO) downlink. Exploiting the special dual-polarized antenna structure, the polarizationbased subgrouping technique is adopted which enjoys low implementation complexity, low feedback overhead, and good performance. Based on this, the proposed robust fairness-based EE precoding design aims at maximizing the minimum EE, i.e., the worst-case EE, achieved among all users with the norm bounded channel errors. Further, the formulated nonconvex EE optimization problem is transformed into a series of standard semidefinite programming (SDP) problems, which can be effectively solved by the convex optimization technique. Simulation results demonstrate the robust EE performance advantages of the proposed polarizatio

    Robust energy-efficient precoding optimization for dual-polarized multiuser MIMO downlink

    No full text
    In this paper, we investigate the robust fairness-based energy efficiency (EE) optimization of the dual-polarized multiuser multiple-input multiple-output (MIMO) downlink. Exploiting the special dual-polarized antenna structure, the polarization-based subgrouping technique is adopted which enjoys low implementation complexity, low feedback overhead and good performance. Based on this, the proposed robust fairness-based EE precoding design aims at maximizing the minimum EE, i.e., the worst-case EE, achieved among all users with the norm bounded channel errors. Further, the formulated nonconvex EE optimization problem is transformed into a series of standard semidefinite programming (SDP) problems, which can be effectively solved by the convex optimization techinique. Simulation results demonstrate the robust EE performance advantages of the proposed polarization-based subgrouping precoding scheme.This work was supported by the National Natural Science Foundation of China under Grant 61671058

    The Influence of Bleeding Direction on Starting Performance of Three-Dimensional Inward Turning Inlet

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    Bleeding is an effective method to improve the starting performance of the inlet, and the conventional method often adopts the bleeding to longitudinal direction. This article proposes the use of transversal bleeding method to explore the influence on starting capacity by changing the bleeding direction. The paper designs 6 bleeding inlets. By calculating the starting performance, it is found that the projected bleeding rate of the inlet, which is the direct factor influencing the starting performance, would change due to the direction change of bleeding, although designed with the same entrance. For the inlet designed with longitudinal slots and bleeding, it could reach the starting state at Mach 3.6, but it showed the unstart state when they are transversal direction. The same entrance, when inlet is designed by transversal bleeding with longitudinal slots, the starting Mach number would decrease to 3.8. For the changes of aerodynamic capabilities, there would be the “point jump” tendency when reaching starting state, but the same inlets would keep the similar performance when they get the starting state

    Genome-Wide Identification and Characterization of the CsFHY3/FAR1 Gene Family and Expression Analysis under Biotic and Abiotic Stresses in Tea Plants (Camellia sinensis)

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    The FHY3/FAR1 transcription factor family, derived from transposases, plays important roles in light signal transduction, and in the growth and development of plants. However, the homologous genes in tea plants have not been studied. In this study, 25 CsFHY3/FAR1 genes were identified in the tea plant genome through a genome-wide study, and were classified into five subgroups based on their phylogenic relationships. Their potential regulatory roles in light signal transduction and photomorphogenesis, plant growth and development, and hormone responses were verified by the existence of the corresponding cis-acting elements. The transcriptome data showed that these genes could respond to salt stress and shading treatment. An expression analysis revealed that, in different tissues, especially in leaves, CsFHY3/FAR1s were strongly expressed, and most of these genes were positively expressed under salt stress (NaCl), and negatively expressed under low temperature (4 °C) stress. In addition, a potential interaction network demonstrated that PHYA, PHYC, PHYE, LHY, FHL, HY5, and other FRSs were directly or indirectly associated with CsFHY3/FAR1 members. These results will provide the foundation for functional studies of the CsFHY3/FAR1 family, and will contribute to the breeding of tea varieties with high light efficiency and strong stress resistance
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