229 research outputs found

    Changes in the milk metabolome of the Giant Panda (Ailuropoda melanoleuca) with time after birth: three phases in early lactation and progressive individual differences

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    Ursids (bears) in general, and giant pandas in particular, are highly altricial at birth. The components of bear milks and their changes with time may be uniquely adapted to nourish relatively immature neonates, protect them from pathogens, and support the maturation of neonatal digestive physiology. Serial milk samples collected from three giant pandas in early lactation were subjected to untargeted metabolite profiling and multivariate analysis. Changes in milk metabolites with time after birth were analysed by Principal Component Analysis, Hierarchical Cluster Analysis and further supported by Orthogonal Partial Least Square-Discriminant Analysis, revealing three phases of milk maturation: days 1–6 (Phase 1), days 7–20 (Phase 2), and beyond day 20 (Phase 3). While the compositions of Phase 1 milks were essentially indistinguishable among individuals, divergences emerged during the second week of lactation. OPLS regression analysis positioned against the growth rate of one cub tentatively inferred a correlation with changes in the abundance of a trisaccharide, isoglobotriose, previously observed to be a major oligosaccharide in ursid milks. Three artificial milk formulae used to feed giant panda cubs were also analysed, and were found to differ markedly in component content from natural panda milk. These findings have implications for the dependence of the ontogeny of all species of bears, and potentially other members of the Carnivora and beyond, on the complexity and sequential changes in maternal provision of micrometabolites in the immediate period after birth

    Prolonged transition time between colostrum and mature milk in a bear, the giant panda, Ailuropoda melanoleuca

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    Bears produce the most altricial neonates of any placental mammal. We hypothesized that the transition from colostrum to mature milk in bears reflects a temporal and biochemical adaptation for altricial development and immune protection. Comparison of bear milks with milks of other eutherians yielded distinctive protein profiles. Proteomic and metabolomic analysis of serial milk samples collected from six giant pandas showed a prolonged transition from colostrum to main-phase lactation over approximately 30 days. Particularly striking are the persistence or sequential appearance of adaptive and innate immune factors. The endurance of immunoglobulin G suggests an unusual duration of trans-intestinal absorption of maternal antibodies, and is potentially relevant to the underdeveloped lymphoid system of giant panda neonates. Levels of certain milk oligosaccharides known to exert anti-microbial activities and/or that are conducive to the development of neonatal gut microbiomes underwent an almost complete changeover around days 20–30 postpartum, coincident with the maturation of the protein profile. A potential metabolic marker of starvation was detected, the prominence of which may reflect the natural postpartum period of anorexia in giant panda mothers. Early lactation in giant pandas, and possibly in other ursids, appears to be adapted for the unique requirements of unusually altricial eutherian neonates

    Design of an Aircraft Rolling Bearings Platform and its Thermal Performance Evaluation

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    The thermal instability is one crucial factor leading to low bearing operation performance. This paper presents a novel experiment device for thermal performance investigation of an aircraft rolling bearings. A bidirectional fixing structure was designed to balance the spindle thermal deformation. The hydraulic loading was used and the oil injection manner was adopted in the new device. Experimental test was conducted using the new device and experimental results were compared with the calculation based on the temperature and thermal nodes theory. The comparison demonstrates that the temperature distribution trends between the theoretical and experimental results remained the same; specifically, the error between the theoretical and experimental results was 1.0 % under the condition of 200 kg load and 2250 rpm driving speed. Consequently, the analysis result shows that the new device is feasible and reliable to provide precise thermal characteristics for the aircraft rolling bearings

    Cosmic Radio Background from Primordial Black Holes at Cosmic Dawn

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    The presence of an extra radio background besides the cosmic microwave background has important implications for the observation of the 21-cm signal during the cosmic Dark Ages, Cosmic Dawn, and epoch of Reionization. The strong absorption trough found in the 21-cm global spectrum measured by the EDGES experiment, which has a much greater depth than the standard model prediction, has drawn great interest to this scenario, but more generally it is still of great interest to consider such a cosmic radio background (CRB) in the early Universe. To be effective in affecting the 21-cm signal at early time, such a radio background must be produced by sources which can emit strong radio signals but modest amount of X-rays, so that the gas is not heated up too early. We investigate the scenario that such a radio background is produced by the primordial black holes (PBHs). For PBH with a single mass, we find that if the PBHs' abundance log(fPBH)\log(f_{\rm PBH}) (ratio of total PBH mass density to total matter density) and mass satisfy the relation log(fPBH)1.8log(M/M)3.5\log(f_{\rm PBH}) \sim -1.8\log(M_\bullet/{\rm M}_{\odot})-3.5 for 1MM300M1\,{\rm M}_\odot \lesssim M_\bullet \lesssim 300 {\rm M}_\odot, and have jet emission, they can generate a CRB required for reproducing the 21-cm absorption signal seen by the EDGES. The accretion rate can be boosted if the PBHs are surrounded by dark matter halos, which permits lower fPBHf_{\rm PBH} value to satisfy the EDGES observation. In the latter scenario, since the accretion rate can evolve rapidly during the Cosmic Dawn, the frequency (redshift) and depth of the absorption trough can determine the mass and abundance of the PBHs simultaneously. For absorption trough redshift \sim 17 and depth 500\sim -500 mK, it corresponds to M1.05MM_\bullet \sim 1.05\,{\rm M}_{\odot} and fPBH1.5×104f_{\rm PBH}\sim 1.5\times10^{-4}.Comment: 16 pages, 13 figures, accepted for publication in PR

    Application of photo-crosslinkable gelatin methacryloyl in wound healing

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    Wound healing is a complex and coordinated biological process easily influenced by various internal and external factors. Hydrogels have immense practical importance in wound nursing because of their environmental moisturising, pain-relieving, and cooling effects. As photo-crosslinkable biomaterials, gelatine methacryloyl (GelMA) hydrogels exhibit substantial potential for tissue repair and reconstruction because of their tunable and beneficial properties. GelMA hydrogels have been extensively investigated as scaffolds for cell growth and drug release in various biomedical applications. They also hold great significance in wound healing because of their similarity to the components of the extracellular matrix of the skin and their favourable physicochemical properties. These hydrogels can promote wound healing and tissue remodelling by reducing inflammation, facilitating vascularisation, and supporting cell growth. In this study, we reviewed the applications of GelMA hydrogels in wound healing, including skin tissue engineering, wound dressing, and transdermal drug delivery. We aim to inspire further exploration of their potential for wound healing

    Discovering genetic linkage between periodontitis and type 1 diabetes: A bioinformatics study

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    Background: Relationship between periodontitis (PD) and type 1 diabetes (T1D) has been reported, but the detailed pathogenesis requires further elucidation. This study aimed to reveal the genetic linkage between PD and T1D through bioinformatics analysis, thereby providing novel insights into scientific research and clinical treatment of the two diseases.Methods: PD-related datasets (GSE10334, GSE16134, GSE23586) and T1D-related datasets(GSE162689)were downloaded from NCBI Gene Expression Omnibus (GEO). Following batch correction and merging of PD-related datasets as one cohort, differential expression analysis was performed (adjusted p-value <0.05 and ∣log2  fold change| > 0.5), and common differentially expressed genes (DEGs) between PD and T1D were extracted. Functional enrichment analysis was conducted via Metascape website. The protein-protein interaction (PPI) network of common DEGs was generated in The Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) database. Hub genes were selected by Cytoscape software and validated by receiver operating characteristic (ROC) curve analysis.Results: 59 common DEGs of PD and T1D were identified. Among these DEGs, 23 genes were commonly upregulated, and 36 genes were commonly downregulated in both PD- and T1D-related cohorts. Functional enrichment analysis indicated that common DEGs were mainly enriched in tube morphogenesis, supramolecular fiber organization, 9 + 0 non-motile cilium, plasma membrane bounded cell projection assembly, glomerulus development, enzyme-linked receptor protein signaling pathway, endochondral bone morphogenesis, positive regulation of kinase activity, cell projection membrane and regulation of lipid metabolic process. After PPI construction and modules selection, 6 hub genes (CD34, EGR1, BBS7, FMOD, IGF2, TXN) were screened out and expected to be critical in linking PD and T1D. ROC analysis showed that the AUC values of hub genes were all greater than 70% in PD-related cohort and greater than 60% in T1D-related datasets.Conclusion: Shared molecular mechanisms between PD and T1D were revealed in this study, and 6 hub genes were identified as potential targets in treating PD and T1D

    Composition and Role of Lignin in Biochemicals

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    The term lignin is derived from lignum, which means plant wood. Plant wood are mainly composed of extractives, hemicellulose, cellulose, and lignin. The lignin is a cross-linked polymer, made of three phenylpropanoid precursors, p-coumaryl, synapyl, and conniferyl alcohols. It is the most abundant polymer in plant world and act mechanically as a natural glue to bind hemicellulose and cellulose. Lignin is amorphous, soluble in alkali, condenses with phenol and has high melting temperature. The function of lignin is to protect the carbohydrates of the biomass from degradation, thus provide stability. The chapter includes information on types of lignin, structure, isolation, degradation, and transformation in to market value chemicals. The application of lignin and lignin base monomers for synthesis of plastic, hydrogels, adhesives, chemicals, fuels and other value added materials at industrial scale

    Accounting of public preferences and valuation of terrestrial and aquatic ecosystem services restoration: Evidence from Northwestern China

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    The emphasis of current study is on the assessment of households’ willingness to pay (WTP) and preference heterogeneity for the upgradation of degraded terrestrial and aquatic ecosystem services across sub-basins of Heihe River. A sum of 1679 households were interviewed through choice experiment, and random parameter logit model is applied for welfare estimation. The estimated results signified the importance of selected terrestrial and aquatic ecological attributes. Sampled respondents of upper and middle basins placed highest WTP for reducing the emission of greenhouse gases among all other attributes and the WTP amount was 99.27 and 66.49 Yuan/Year respectively. Whereas in lower basin, improvement in landscape of farmland was highly valued, i.e., 107 Yuan/Year. In terrestrial ecosystem services the lowest WTP was recorded for Ejinaqi oasis size in all sub basins. In aquatic ecosystem services, improving water quality was the most valued attribute in all sub basins, and the corresponding WTP values are 122.81, 99.87 and 177.43 Yuan/Year in upper, middle and lower basins respectively, which ensure the significance of water quality in the entire basin. In aquatic ecosystem services the lowest WTP amount was recorded for leisure and entertainment conditions in each sub basin.publishedVersio

    Experimental investigation of the uncertainty principle for radial degrees of freedom

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    While the uncertainty principle for linear position and linear momentum, and more recently for angular position and angular momentum, is well established, its radial equivalent has so far eluded researchers. Here we exploit the logarithmic radial position, ln r , and hyperbolic momentum, P H , to formulate a rigorous uncertainty principle for the radial degree of freedom of transverse light modes. We show that the product of their uncertainties is bounded by Planck’s constant, Δ ln r · Δ P H ≥ ℏ / 2 , and identify a set of radial intelligent states that satisfy the equality. We illustrate the radial uncertainty principle for a variety of intelligent states, by preparing transverse light modes with suitable radial profiles. We use eigenmode projection to measure the corresponding hyperbolic momenta, confirming the minimum uncertainty bound. Optical systems are most naturally described in terms of cylindrical coordinates, and our radial uncertainty relation provides the missing piece in characterizing optical quantum measurements, providing a new platform for the fundamental tests and applications of quantum optics
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