Effects of polymer additives in the bulk of turbulent thermal convection

We present experimental evidence that a minute amount of polymer additives can significantly enhance heat transport in the bulk region of turbulent thermal convection. The effects of polymer additives are found to be the \textit{suppression} of turbulent background fluctuations that give rise to incoherent heat fluxes that make no net contribution to heat transport, and at the same time to \textit{increase} the coherency of temperature and velocity fields. The suppression of small-scale turbulent fluctuations leads to more coherent thermal plumes that result in the heat transport enhancement. The fact that polymer additives can increase the coherency of thermal plumes is supported by the measurements of a number of local quantities, such as the extracted plume amplitude and width, the velocity autocorrelation functions and the velocity-temperature cross-correlation coefficient. The results from local measurements also suggest the existence of a threshold value for the polymer concentration, only above which can significant modification of the plume coherent properties and enhancement of the local heat flux be observed. Estimation of the plume emission rate suggests that the second effect of polymer additives is to stabilize the thermal boundary layers.Comment: 8 figures, 11 page

Expression of hypoxia inducible factor-1α and vascular endothelial growth factor-C in human chronic periodontitis

AbstractBackground/purposeEvidence shows that there is a relationship between hypoxia and inflammatory response in periodontitis. Hypoxia-inducible factor (HIF)-1α is a major regulator of energy homeostasis and cellular adaptation to low oxygen stress. Although experimental results demonstrate an association between HIF-1α and vascular endothelial growth factor (VEGF)-C in tumor angiogenesis, the role of HIF-1α and VEGF-C in the pathogenesis of periodontitis is still ambiguous. So far, limited attention has been given to the role of hypoxia and VEGF-C in periodontitis. The present study aimed to investigate the expression and distribution of HIF-1α and VEGF-C in gingival tissue samples from patients with different stages of chronic periodontitis and healthy individuals.Materials and methodsA total of 56 samples were involved in this study, including moderate chronic periodontitis (n = 20), advanced chronic periodontitis (n = 20), and healthy control tissues (n = 16). The gingival specimens were stained with hematoxylin and eosin for histopathology. The expression of HIF-1α and VEGF-C in gingival tissues was detected by immunohistochemical staining.ResultsHIF-1α and VEGF-C were found in gingival tissues from patients with different stages of chronic periodontitis as well as healthy control tissues. HIF-1α protein was expressed mainly in the epithelial layer of gingival tissues, and VEGF-C protein was mostly located in the connective tissue papilla of gingival tissues. Compared with healthy controls, the expression of HIF-1α and VEGF-C in chronic periodontitis groups was significantly higher (P < 0.01), and the density of HIF-1α and VEGF-C in advanced chronic periodontitis group was even significantly higher than that in the moderate chronic periodontitis group (P < 0.01).ConclusionOur results suggest that the expression of HIF-1α and VEGF-C increased with severity of periodontitis. So, we conclude that HIF-1α may play an important role in the pathophysiology of human periodontitis and may be related to the function of VEGF-C during periodontitis

Activity modulation and allosteric control of a scaffolded DNAzyme using a dynamic DNA nanostructure.

Recognition of the fundamental importance of allosteric regulation in biology dates back to not long after its discovery in the 1960s. Our ability to rationally engineer this potentially useful property into normally non-allosteric catalysts, however, remains limited. In response we report a DNA nanotechnology-enabled approach for introducing allostery into catalytic nucleic acids. Specifically, we have grafted one or two copies of a peroxidase-like DNAzyme, hemin-bound G-quadruplex (hemin-G), onto a DNA tetrahedral nanostructure in such a manner as to cause them to interact, modulating their catalytic activity. We achieve allosteric regulation of these catalysts by incorporating dynamically responsive oligonucleotides that respond to specific "effector" molecules (complementary oligonucleotides or small molecules), altering the spacing between the catalytic sites and thus regulating their activity. This designable approach thus enables subtle allosteric modulation in DNAzymes that is potentially of use for nanomedicine and nanomachines

GRB 120729A: External Shock Origin for Both the Prompt Gamma-Ray Emission and Afterglow

Gamma-ray burst (GRB) 120729A was detected by Swift/BAT and Fermi/GBM, and then rapidly observed by Swift/XRT, Swift/UVOT, and ground-based telescopes. It had a single long and smooth \gamma-ray emission pulse, which extends continuously to the X-rays. We report Lick/KAIT observations of the source, and make temporal and spectral joint fits of the multiwavelength light curves of GRB 120729A. It exhibits achromatic light-curve behavior, consistent with the predictions of the external shock model. The light curves are decomposed into four typical phases: onset bump (Phase I), normal decay (Phase II), shallow decay (Phase III), and post-jet break (Phase IV). The spectral energy distribution (SED) evolves from prompt \gamma-ray emission to the afterglow with photon index from Γγ=1.36 to Γ≈1.75. There is no obvious evolution of the SED during the afterglow. ...(Please see article full tet for complete abstract.

Risk factors for high-altitude headache upon acute high-altitude exposure at 3700 m in young Chinese men: a cohort study.

BackgroundThis prospective and observational study aimed to identify demographic, physiological and psychological risk factors associated with high-altitude headache (HAH) upon acute high-altitude exposure.MethodsEight hundred fifty subjects ascended by plane to 3700 m above Chengdu (500 m) over a period of two hours. Structured Case Report Form (CRF) questionnaires were used to record demographic information, physiological examinations, psychological scale, and symptoms including headache and insomnia a week before ascending and within 24 hours after arrival at 3700 m. Binary logistic regression models were used to analyze the risk factors for HAH.ResultsThe incidence of HAH was 73.3%. Age (p =0.011), physical labor intensity (PLI) (p =0.044), primary headache history (p &lt;0.001), insomnia (p &lt;0.001), arterial oxygen saturation (SaO2) (p =0.001), heart rate (HR) (p =0.002), the Self-Rating Anxiety Scale (SAS) (p &lt;0.001), and the Epworth Sleepiness Scale (ESS) (p &lt;0.001) were significantly different between HAH and non-HAH groups. Logistic regression models identified primary headache history, insomnia, low SaO2, high HR and SAS as independent risk factors for HAH.ConclusionsInsomnia, primary headache history, low SaO2, high HR, and high SAS score are the risk factors for HAH. Our findings will provide novel avenues for the study, prevention and treatment of HAH

PRIOR: Personalized Prior for Reactivating the Information Overlooked in Federated Learning

Classical federated learning (FL) enables training machine learning models without sharing data for privacy preservation, but heterogeneous data characteristic degrades the performance of the localized model. Personalized FL (PFL) addresses this by synthesizing personalized models from a global model via training on local data. Such a global model may overlook the specific information that the clients have been sampled. In this paper, we propose a novel scheme to inject personalized prior knowledge into the global model in each client, which attempts to mitigate the introduced incomplete information problem in PFL. At the heart of our proposed approach is a framework, the PFL with Bregman Divergence (pFedBreD), decoupling the personalized prior from the local objective function regularized by Bregman divergence for greater adaptability in personalized scenarios. We also relax the mirror descent (RMD) to extract the prior explicitly to provide optional strategies. Additionally, our pFedBreD is backed up by a convergence analysis. Sufficient experiments demonstrate that our method reaches the state-of-the-art performances on 5 datasets and outperforms other methods by up to 3.5% across 8 benchmarks. Extensive analyses verify the robustness and necessity of proposed designs.Comment: Accepted by NeurIPS 202

Sequence Characterization of the MC1R Gene in Yak (Poephagus grunniens) Breeds with Different Coat Colors

Melanocortin 1 receptor (MC1R) gene plays a key role in determining coat color in several species, including the cattle. However, up to now there is no report regarding the MC1R gene and the potential association of its mutations with coat colors in yak (Poephagus grunniens). In this study, we sequenced the encoding region of the MC1R gene in three yak breeds with completely white (Tianzhu breed) or black coat color (Jiulong and Maiwa breeds). The predicted coding region of the yak MC1R gene resulted of 954 bp, the same to that of the wild-type cattle sequence, with >99% identity. None of the mutation events reported in cattle was found. Comparing the yak obtained sequences, five nucleotide substitutions were detected, which defined three haplotypes (EY1, EY2, and EY3). Of the five mutations, two, characterizing the EY1 haplotype, were nonsynonymous substitutions (c.340C>A and c.871G>A) causing amino acid changes located in the first extracellular loop (p.Q114K) and in the seventh transmembrane region (p.A291T). In silico prediction might indicate a functional effect of the latter substitution. However, all three haplotypes were present in the three yak breeds with relatively consistent frequency distribution, despite of their distinguished coat colors, which suggested that there was no across-breed association between haplotypes or genotypes and black/white phenotypes, at least in the investigated breeds. Other genes may be involved in affecting coat color in the analyzed yaks