Exploiting the misalignment of the serrated trailing edges for improved aerofoil broadband noise reduction

This paper presents the experimental results of adding variable flap angles to the serrated trailing edges and their effects on the self-noise radiation of an aerofoil. The investigation included aeroacoustics and wake flow measurements on an NACA 65-(12)10 aerofoil. This paper explores further combinations of positive and negative serration flap angles, U and L respectively, across the spanwise extent of the trailing edge. A new parameter, the serration oscillation wavelength (λ), was also included. The study investigates five individual cases, Baseline (B), Straight-Serration (SS), sIngle-Flapped-Serration (IFS), Multi-FlappedSerration (MFS), Split-Flapped-Serration (SFS) and Spanwise-Wavy-Serration (SWS). The serration amplitude and wavelength remained consistent as 30 mm and 3.3 mm respectively. It is clear that all the “misaligned” trailing edges produce different noise characteristics compared to the conventional SS trailing edge. At low-to-mid frequency range, the conventional SS trailing edge still outperforms both the MFS and SFS trailing edges. However, from mid-to-high frequency, both the MFS and SFS trailing edges can achieve higher noise reduction than the SS trailing edge considerably. At very high frequency, where the SS trailing edge would otherwise experience noise increase, there is no noise increase for both the MFS and SFS trailing edges because the periodic misalignment reduces the crossflow component in the space between adjacent members of the serration. The SWS trailing edge produces the same level of noise reduction as the SS trailing edge across the low-to-mid frequency range. From mid-to-high frequency range, the SWS trailing edge outperforms the SS trailing edge, but the level of further noise reduction it can achieve is less than those of MFS and SFS trailing edges. At very high frequency, the SWS begins to experience slightly noise increase over the baseline, B, trailing edge. However, the increase in noise level by the SWS trailing edge at this high frequency range is still less than that by the SS trailing edge. The near-wake flow measurement results provide some explanations for the mechanisms underpinning the broadband noise reduction and high frequency noise suppression by these trailing edge devices

A case-control study and meta-analysis of the association of eNOS rs1799983 SNP with stroke risk

The endothelial nitric oxide synthase (eNOS) rs1799983 polymorphism is known to increase the risk towards stroke, but data is under-reported in Malaysian population. Therefore, this study sought to investigate this association in a Malaysian population and in a comprehensive meta-analysis. Genotyping of the eNOS rs1799983 polymorphism was performed for 241 Malaysians using a hydrolysis probe. Odd ratio with 95% confidence interval was calculated. Meta-analysis was conducted using the Comprehensive Meta-Analysis software ver. 2.2.064. A p-value less than 0.05 was considered statistically significant. Overall, our results showed that the presence of eNOS rs1799983-T allele increases the risk towards stroke, particularly in males, fast-food goers and Malaysian Chinese. The meta-analysis showed that the rs1799983 polymorphism is significantly associated with an increase ischemic stroke risk in the recessive and allelic models. After stratified with population, these associations remain significant in the Asian population but not in the Caucasian population. In summary, this study establishes a significant relationship between the eNOS rs1799983 polymorphism with gender, lifestyle and ethnicity differences towards stroke risk in the Malaysian population. In addition, our meta-analysis suggests that the eNOS rs1799983 polymorphism is associated with an increase risk of ischemic stroke

Structured Porous Coated Cylinder Modifications Based on Internal Flow Field Data

Session: Acoustic / Fluid Dynamics Interactions IIView Video Presentation: https://doi.org/10.2514/6.2023-3926.vidPorous coated cylinders have been proven to reduce vortex shedding tones relative to a bare cylinder. However, many porous treatments are based on the use of very complex, open-cell structures to manipulate turbulent flow. Due to complex geometries the physical mechanisms which can be drawn are problematic to investigate due to a typically randomised porous structure. The novel 3D printed Structured Porous Coated Cylinder (SPCC), which mimics the acoustics of open-cell foam's noise closely, absolves this issue thereby allowing improved observability and modifications. This study aims to draw from previous works and to investigate modified SPCCs to further understand the internal flows which attenuate fundamental vortex shedding tones. The initial study highlighted presented a preliminary analysis on the acoustic far-field of cylindrical structures and the validation against prior works. Following on from this, this paper highlights the modifications to the existing SPCC structure to affect the regions of stagnated flow within the porous layers, to investigate how these internal flows have impacted the vortex shedding attenuating capacity of the SPCC. Conducted at Brunel University London, the acoustic data shown confirms the ability of the SPCC to significantly reduce turbulent shedding noise over its bare cylinder counterparts and the three modified SPCCs proved the importance of the streamwise communication in the internal structure of the SPCC and that the stagnation regions as stipulated by earlier studies can be filled which retains the acoustic performance and most likely reduces the drag. Lastly, the removal of the ability for the flow to travel in the spanwise direction within the SPCC has been shown to improve the acoustic far field radiation over the original SPCC.The authors would like to thank the EPSRC for the financial support from the Doctoral Training Partnership (DTP); Engineering & Physical Sciences Research Council (EP/V006886/1) QUiet Aerofoil with ADaptive PORous Surfaces (QUADPORS)

Optical detection of single non-absorbing molecules using the surface plasmon of a gold nanorod

Current optical detection schemes for single molecules require light absorption, either to produce fluorescence or direct absorption signals. This severely limits the range of molecules that can be detected, because most molecules are purely refractive. Metal nanoparticles or dielectric resonators detect non-absorbing molecules by a resonance shift in response to a local perturbation of the refractive index, but neither has reached single-protein sensitivity. The most sensitive plasmon sensors to date detect single molecules only when the plasmon shift is amplified by a highly polarizable label or by a localized precipitation reaction on the particle's surface. Without amplification, the sensitivity only allows for the statistical detection of single molecules. Here we demonstrate plasmonic detection of single molecules in realtime, without the need for labeling or amplification. We monitor the plasmon resonance of a single gold nanorod with a sensitive photothermal assay and achieve a ~ 700-fold increase in sensitivity compared to state-of-the-art plasmon sensors. We find that the sensitivity of the sensor is intrinsically limited due to spectral diffusion of the SPR. We believe this is the first optical technique that detects single molecules purely by their refractive index, without any need for photon absorption by the molecule. The small size, bio-compatibility and straightforward surface chemistry of gold nanorods may open the way to the selective and local detection of purely refractive proteins in live cells

BPS black holes in N=2 D=4 gauged supergravities

We construct and analyze BPS black hole solutions in gauged N=2, D=4 supergravity with charged hypermultiplets. A class of solutions can be found through spontaneous symmetry breaking in vacua that preserve maximal supersymmetry. The resulting black holes do not carry any hair for the scalars. We demonstrate this with explicit examples of both asymptotically flat and anti-de Sitter black holes. Next, we analyze the BPS conditions for asymptotically flat black holes with scalar hair and spherical or axial symmetry. We find solutions only in cases when the metric contains ripples and the vector multiplet scalars become ghost-like. We give explicit examples that can be analyzed numerically. Finally, we comment on a way to circumvent the ghost-problem by introducing also fermionic hair.Comment: 40 pages, 2 figures; v2 references added; v3 minor changes, published versio

Effect of remote ischemic preConditioning on liver injury in patients undergoing liver resection: the ERIC-LIVER trial

OBJECTIVE: Novel hepatoprotective strategies are needed to improve clinical outcomes during liver surgery. There is mixed data on the role of remote ischemic preconditioning (RIPC). We investigated RIPC in partial hepatectomy for primary hepatocellular carcinoma (HCC). METHODS: This was a Phase II, single-center, sham-controlled, randomized controlled trial (RCT). The primary hypothesis was that RIPC would reduce acute liver injury following surgery indicated by serum alanine transferase (ALT) 24 h following hepatectomy in patients with primary HCC, compared to sham. Patients were randomized to receive either four cycles of 5 min/5 min arm cuff inflation/deflation immediately prior to surgery, or sham. Secondary endpoints included clinical, biochemical and pathological outcomes. Liver function measured by Indocyanine Green pulse densitometry was performed in a subset of patients. RESULTS: 24 and 26 patients were randomized to RIPC and control groups respectively. The groups were balanced for baseline characteristics, except the duration of operation was longer in the RIPC group. Median ALT at 24 h was similar between groups (196 IU/L IQR 113.5-419.5 versus 172.5 IU/L IQR 115-298 respectively, p = 0.61). Groups were similar in secondary endpoints. CONCLUSION: This RCT did not demonstrate beneficial effects with RIPC on serum ALT levels 24 h after partial hepatectomy

Adjunctive mood stabilizer treatment for hospitalized schizophrenia patients: Asia psychotropic prescripton study (2001-2008)

Recent studies indicate relatively high international rates of adjunctive psychotropic medication, including mood stabilizers, for patients with schizophrenia. Since such treatments are little studied in Asia, we examined the frequency of mood-stabilizer use and its clinical correlates among hospitalized Asian patients diagnosed with schizophrenia in 2001-2008. We evaluated usage rates of mood stabilizers with antipsychotic drugs, and associated factors, for in-patients diagnosed with DSM-IV schizophrenia in 2001, 2004 and 2008 in nine Asian regions: China, Hong Kong, India, Korea, Japan, Malaysia, Taiwan, Thailand, and Singapore. Overall, mood stabilizers were given to 20.4% (n=1377/6761) of hospitalized schizophrenia patients, with increased usage over time. Mood-stabilizer use was significantly and independently associated in multivariate logistic modeling with: aggressive behaviour, disorganized speech, year sampled (2008 vs. earlier), multiple hospitalizations, less negative symptoms, younger age, with regional variation (Japan, Hong Kong, Singapore>Taiwan or China). Co-prescription of adjunctive mood stabilizers with antipsychotics for hospitalized Asian schizophrenia patients increased over the past decade, and was associated with specific clinical characteristics. This practice parallels findings in other countries and illustrates ongoing tension between evidence-based practice vs. individualized, empirical treatment of psychotic disorders.published_or_final_versio

Influence of FADS Polymorphisms on Tracking of Serum Glycerophospholipid Fatty Acid Concentrations and Percentage Composition in Children

Tracking of fatty acid (FA) contribution to plasma or serum lipids over time was shown in children and adults. However, the potential role of FADS gene variants has not been investigated. Serum GP FA composition of 331 children aged 2 and 6 years, participating in an ongoing birth cohort study, was analyzed. Correlation coefficients were estimated to describe FA tracking over 4 years and to assess the influence of FADS variants on tracking. We found low to moderate tracking (r = 0.12-0.49) of FA compositions and concentration between 2 and 6 years. Concentration changes of total monounsaturated FA and total saturated FA over time correlated closely (r = 0.79) but percentage values were unrelated (r = -0.02). Tracking for n-6 long chain polyunsaturated fatty acid (LC-PUFA) concentrations was lower in subjects homozygous for the major allele of FADS variants and higher in carriers of at least one minor allele, whereas for total n-3 LC-PUFA concentrations and compositions this was vice versa. For individual n-3 PUFA inconsistent results were found. Serum GP FA composition shows low to moderate tracking over 4 years with a higher tracking for LC-PUFA metabolites than for their precursor FA. Serum PUFA levels and their tracking seem to be more influenced by lipid and lipoprotein metabolism than by FA specific pathways

Influence of FADS Polymorphisms on Tracking of Serum Glycerophospholipid Fatty Acid Concentrations and Percentage Composition in Children

BACKGROUND: Tracking of fatty acid (FA) contribution to plasma or serum lipids over time was shown in children and adults. However, the potential role of FADS gene variants has not been investigated. METHODS AND PRINCIPAL FINDINGS: Serum GP FA composition of 331 children aged 2 and 6 years, participating in an ongoing birth cohort study, was analyzed. Correlation coefficients were estimated to describe FA tracking over 4 years and to assess the influence of FADS variants on tracking. We found low to moderate tracking (r = 0.12-0.49) of FA compositions and concentration between 2 and 6 years. Concentration changes of total monounsaturated FA and total saturated FA over time correlated closely (r = 0.79) but percentage values were unrelated (r = -0.02). Tracking for n-6 long chain polyunsaturated fatty acid (LC-PUFA) concentrations was lower in subjects homozygous for the major allele of FADS variants and higher in carriers of at least one minor allele, whereas for total n-3 LC-PUFA concentrations and compositions this was vice versa. For individual n-3 PUFA inconsistent results were found. CONCLUSIONS AND SIGNIFICANCE: Serum GP FA composition shows low to moderate tracking over 4 years with a higher tracking for LC-PUFA metabolites than for their precursor FA. Serum PUFA levels and their tracking seem to be more influenced by lipid and lipoprotein metabolism than by FA specific pathways